From: Rusty Russell Date: Wed, 31 Aug 2011 05:39:16 +0000 (+0930) Subject: tdb2: import TDB1 code. X-Git-Url: https://git.ozlabs.org/?p=ccan;a=commitdiff_plain;h=19e6c1a250ade1e7204ada17163294855585e825;hp=476567430be6962625bf399192e20938985232c7 tdb2: import TDB1 code. We import the entire codebase, putting a "tdb1_" prefix on the files and changing the "tdb_" prefix to "tdb1_" everywhere. The next patches will gradually merge it with the TDB2 code where necessary. --- diff --git a/ccan/tdb2/tdb1.h b/ccan/tdb2/tdb1.h new file mode 100644 index 00000000..12c13efe --- /dev/null +++ b/ccan/tdb2/tdb1.h @@ -0,0 +1,226 @@ +#ifndef TDB1_H +#define TDB1_H + +/* + Unix SMB/CIFS implementation. + + trivial database library (version 1 compat functions) + + Copyright (C) Andrew Tridgell 1999-2004 + Copyright (C) Rusty Russell 2011 + + ** NOTE! The following LGPL license applies to the tdb + ** library. This does NOT imply that all of Samba is released + ** under the LGPL + + This library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 3 of the License, or (at your option) any later version. + + This library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with this library; if not, see . +*/ + +#ifndef _SAMBA_BUILD_ +/* For mode_t */ +#include +/* For O_* flags. */ +#include +/* For sig_atomic_t. */ +#include +#endif + +/** Flags to tdb1_store() */ +#define TDB1_REPLACE 1 /** Unused */ +#define TDB1_INSERT 2 /** Don't overwrite an existing entry */ +#define TDB1_MODIFY 3 /** Don't create an existing entry */ + +/** Flags for tdb1_open() */ +#define TDB1_DEFAULT 0 /** just a readability place holder */ +#define TDB1_CLEAR_IF_FIRST 1 /** If this is the first open, wipe the db */ +#define TDB1_INTERNAL 2 /** Don't store on disk */ +#define TDB1_NOLOCK 4 /** Don't do any locking */ +#define TDB1_NOMMAP 8 /** Don't use mmap */ +#define TDB1_CONVERT 16 /** Convert endian (internal use) */ +#define TDB1_BIGENDIAN 32 /** Header is big-endian (internal use) */ +#define TDB1_NOSYNC 64 /** Don't use synchronous transactions */ +#define TDB1_SEQNUM 128 /** Maintain a sequence number */ +#define TDB1_VOLATILE 256 /** Activate the per-hashchain freelist, default 5 */ +#define TDB1_ALLOW_NESTING 512 /** Allow transactions to nest */ +#define TDB1_DISALLOW_NESTING 1024 /** Disallow transactions to nest */ +#define TDB1_INCOMPATIBLE_HASH 2048 /** Better hashing: can't be opened by tdb < 1.2.6. */ + +/** The tdb error codes */ +enum TDB1_ERROR {TDB1_SUCCESS=0, TDB1_ERR_CORRUPT, TDB1_ERR_IO, TDB1_ERR_LOCK, + TDB1_ERR_OOM, TDB1_ERR_EXISTS, TDB1_ERR_NOLOCK, TDB1_ERR_LOCK_TIMEOUT, + TDB1_ERR_NOEXIST, TDB1_ERR_EINVAL, TDB1_ERR_RDONLY, + TDB1_ERR_NESTING}; + +/** Debugging uses one of the following levels */ +enum tdb1_debug_level {TDB1_DEBUG_FATAL = 0, TDB1_DEBUG_ERROR, + TDB1_DEBUG_WARNING, TDB1_DEBUG_TRACE}; + +/** The tdb data structure */ +typedef struct TDB1_DATA { + unsigned char *dptr; + size_t dsize; +} TDB1_DATA; + +#ifndef PRINTF_ATTRIBUTE +#if (__GNUC__ >= 3) +/** Use gcc attribute to check printf fns. a1 is the 1-based index of + * the parameter containing the format, and a2 the index of the first + * argument. Note that some gcc 2.x versions don't handle this + * properly **/ +#define PRINTF_ATTRIBUTE(a1, a2) __attribute__ ((format (__printf__, a1, a2))) +#else +#define PRINTF_ATTRIBUTE(a1, a2) +#endif +#endif + +/** This is the context structure that is returned from a db open. */ +typedef struct tdb1_context TDB1_CONTEXT; + +typedef int (*tdb1_traverse_func)(struct tdb1_context *, TDB1_DATA, TDB1_DATA, void *); +typedef void (*tdb1_log_func)(struct tdb1_context *, enum tdb1_debug_level, const char *, ...) PRINTF_ATTRIBUTE(3, 4); +typedef unsigned int (*tdb1_hash_func)(TDB1_DATA *key); + +struct tdb1_logging_context { + tdb1_log_func log_fn; + void *log_private; +}; + +struct tdb1_context *tdb1_open(const char *name, int hash_size, int tdb1_flags, + int open_flags, mode_t mode); + +struct tdb1_context *tdb1_open_ex(const char *name, int hash_size, int tdb1_flags, + int open_flags, mode_t mode, + const struct tdb1_logging_context *log_ctx, + tdb1_hash_func hash_fn); + +void tdb1_set_max_dead(struct tdb1_context *tdb, int max_dead); + +int tdb1_reopen(struct tdb1_context *tdb); + +int tdb1_reopen_all(int parent_longlived); + +void tdb1_set_logging_function(struct tdb1_context *tdb, const struct tdb1_logging_context *log_ctx); + +enum TDB1_ERROR tdb1_error(struct tdb1_context *tdb); + +const char *tdb1_errorstr(struct tdb1_context *tdb); + +TDB1_DATA tdb1_fetch(struct tdb1_context *tdb, TDB1_DATA key); + +int tdb1_parse_record(struct tdb1_context *tdb, TDB1_DATA key, + int (*parser)(TDB1_DATA key, TDB1_DATA data, + void *private_data), + void *private_data); + +int tdb1_delete(struct tdb1_context *tdb, TDB1_DATA key); + +int tdb1_store(struct tdb1_context *tdb, TDB1_DATA key, TDB1_DATA dbuf, int flag); + +int tdb1_append(struct tdb1_context *tdb, TDB1_DATA key, TDB1_DATA new_dbuf); + +int tdb1_close(struct tdb1_context *tdb); + +TDB1_DATA tdb1_firstkey(struct tdb1_context *tdb); + +TDB1_DATA tdb1_nextkey(struct tdb1_context *tdb, TDB1_DATA key); + +int tdb1_traverse(struct tdb1_context *tdb, tdb1_traverse_func fn, void *private_data); + +int tdb1_traverse_read(struct tdb1_context *tdb, tdb1_traverse_func fn, void *private_data); + +int tdb1_exists(struct tdb1_context *tdb, TDB1_DATA key); + +int tdb1_lockall(struct tdb1_context *tdb); + +int tdb1_lockall_nonblock(struct tdb1_context *tdb); + +int tdb1_unlockall(struct tdb1_context *tdb); + +int tdb1_lockall_read(struct tdb1_context *tdb); + +int tdb1_lockall_read_nonblock(struct tdb1_context *tdb); + +int tdb1_unlockall_read(struct tdb1_context *tdb); + +int tdb1_lockall_mark(struct tdb1_context *tdb); + +int tdb1_lockall_unmark(struct tdb1_context *tdb); + +const char *tdb1_name(struct tdb1_context *tdb); + +int tdb1_fd(struct tdb1_context *tdb); + +tdb1_log_func tdb1_log_fn(struct tdb1_context *tdb); + +void *tdb1_get_logging_private(struct tdb1_context *tdb); + +int tdb1_transaction_start(struct tdb1_context *tdb); + +int tdb1_transaction_start_nonblock(struct tdb1_context *tdb); + +int tdb1_transaction_prepare_commit(struct tdb1_context *tdb); + +int tdb1_transaction_commit(struct tdb1_context *tdb); + +int tdb1_transaction_cancel(struct tdb1_context *tdb); + +int tdb1_get_seqnum(struct tdb1_context *tdb); + +int tdb1_hash_size(struct tdb1_context *tdb); + +size_t tdb1_map_size(struct tdb1_context *tdb); + +int tdb1_get_flags(struct tdb1_context *tdb); + +void tdb1_add_flags(struct tdb1_context *tdb, unsigned flag); + +void tdb1_remove_flags(struct tdb1_context *tdb, unsigned flag); + +void tdb1_enable_seqnum(struct tdb1_context *tdb); + +void tdb1_increment_seqnum_nonblock(struct tdb1_context *tdb); + +unsigned int tdb1_jenkins_hash(TDB1_DATA *key); + +int tdb1_check(struct tdb1_context *tdb, + int (*check) (TDB1_DATA key, TDB1_DATA data, void *private_data), + void *private_data); + +/* @} ******************************************************************/ + +/* Low level locking functions: use with care */ +int tdb1_chainlock(struct tdb1_context *tdb, TDB1_DATA key); +int tdb1_chainlock_nonblock(struct tdb1_context *tdb, TDB1_DATA key); +int tdb1_chainunlock(struct tdb1_context *tdb, TDB1_DATA key); +int tdb1_chainlock_read(struct tdb1_context *tdb, TDB1_DATA key); +int tdb1_chainunlock_read(struct tdb1_context *tdb, TDB1_DATA key); +int tdb1_chainlock_mark(struct tdb1_context *tdb, TDB1_DATA key); +int tdb1_chainlock_unmark(struct tdb1_context *tdb, TDB1_DATA key); + +void tdb1_setalarm_sigptr(struct tdb1_context *tdb, volatile sig_atomic_t *sigptr); + +/* wipe and repack */ +int tdb1_wipe_all(struct tdb1_context *tdb); +int tdb1_repack(struct tdb1_context *tdb); + +/* Debug functions. Not used in production. */ +void tdb1_dump_all(struct tdb1_context *tdb); +int tdb1_printfreelist(struct tdb1_context *tdb); +int tdb1_validate_freelist(struct tdb1_context *tdb, int *pnum_entries); +int tdb1_freelist_size(struct tdb1_context *tdb); +char *tdb1_summary(struct tdb1_context *tdb); + +extern TDB1_DATA tdb1_null; + +#endif /* tdb1.h */ diff --git a/ccan/tdb2/tdb1_check.c b/ccan/tdb2/tdb1_check.c new file mode 100644 index 00000000..d62a4b92 --- /dev/null +++ b/ccan/tdb2/tdb1_check.c @@ -0,0 +1,472 @@ + /* + Unix SMB/CIFS implementation. + + trivial database library + + Copyright (C) Rusty Russell 2009 + + ** NOTE! The following LGPL license applies to the tdb + ** library. This does NOT imply that all of Samba is released + ** under the LGPL + + This library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 3 of the License, or (at your option) any later version. + + This library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with this library; if not, see . +*/ +#include "tdb1_private.h" + +/* Since we opened it, these shouldn't fail unless it's recent corruption. */ +static bool tdb1_check_header(struct tdb1_context *tdb, tdb1_off_t *recovery) +{ + struct tdb1_header hdr; + uint32_t h1, h2; + + if (tdb->methods->tdb1_read(tdb, 0, &hdr, sizeof(hdr), 0) == -1) + return false; + if (strcmp(hdr.magic_food, TDB1_MAGIC_FOOD) != 0) + goto corrupt; + + TDB1_CONV(hdr); + if (hdr.version != TDB1_VERSION) + goto corrupt; + + if (hdr.rwlocks != 0 && hdr.rwlocks != TDB1_HASH_RWLOCK_MAGIC) + goto corrupt; + + tdb1_header_hash(tdb, &h1, &h2); + if (hdr.magic1_hash && hdr.magic2_hash && + (hdr.magic1_hash != h1 || hdr.magic2_hash != h2)) + goto corrupt; + + if (hdr.hash_size == 0) + goto corrupt; + + if (hdr.hash_size != tdb->header.hash_size) + goto corrupt; + + if (hdr.recovery_start != 0 && + hdr.recovery_start < TDB1_DATA_START(tdb->header.hash_size)) + goto corrupt; + + *recovery = hdr.recovery_start; + return true; + +corrupt: + tdb->ecode = TDB1_ERR_CORRUPT; + TDB1_LOG((tdb, TDB1_DEBUG_ERROR, "Header is corrupt\n")); + return false; +} + +/* Generic record header check. */ +static bool tdb1_check_record(struct tdb1_context *tdb, + tdb1_off_t off, + const struct tdb1_record *rec) +{ + tdb1_off_t tailer; + + /* Check rec->next: 0 or points to record offset, aligned. */ + if (rec->next > 0 && rec->next < TDB1_DATA_START(tdb->header.hash_size)){ + TDB1_LOG((tdb, TDB1_DEBUG_ERROR, + "Record offset %d too small next %d\n", + off, rec->next)); + goto corrupt; + } + if (rec->next + sizeof(*rec) < rec->next) { + TDB1_LOG((tdb, TDB1_DEBUG_ERROR, + "Record offset %d too large next %d\n", + off, rec->next)); + goto corrupt; + } + if ((rec->next % TDB1_ALIGNMENT) != 0) { + TDB1_LOG((tdb, TDB1_DEBUG_ERROR, + "Record offset %d misaligned next %d\n", + off, rec->next)); + goto corrupt; + } + if (tdb->methods->tdb1_oob(tdb, rec->next+sizeof(*rec), 0)) + goto corrupt; + + /* Check rec_len: similar to rec->next, implies next record. */ + if ((rec->rec_len % TDB1_ALIGNMENT) != 0) { + TDB1_LOG((tdb, TDB1_DEBUG_ERROR, + "Record offset %d misaligned length %d\n", + off, rec->rec_len)); + goto corrupt; + } + /* Must fit tailer. */ + if (rec->rec_len < sizeof(tailer)) { + TDB1_LOG((tdb, TDB1_DEBUG_ERROR, + "Record offset %d too short length %d\n", + off, rec->rec_len)); + goto corrupt; + } + /* OOB allows "right at the end" access, so this works for last rec. */ + if (tdb->methods->tdb1_oob(tdb, off+sizeof(*rec)+rec->rec_len, 0)) + goto corrupt; + + /* Check tailer. */ + if (tdb1_ofs_read(tdb, off+sizeof(*rec)+rec->rec_len-sizeof(tailer), + &tailer) == -1) + goto corrupt; + if (tailer != sizeof(*rec) + rec->rec_len) { + TDB1_LOG((tdb, TDB1_DEBUG_ERROR, + "Record offset %d invalid tailer\n", off)); + goto corrupt; + } + + return true; + +corrupt: + tdb->ecode = TDB1_ERR_CORRUPT; + return false; +} + +/* Grab some bytes: may copy if can't use mmap. + Caller has already done bounds check. */ +static TDB1_DATA get_bytes(struct tdb1_context *tdb, + tdb1_off_t off, tdb1_len_t len) +{ + TDB1_DATA d; + + d.dsize = len; + + if (tdb->transaction == NULL && tdb->map_ptr != NULL) + d.dptr = (unsigned char *)tdb->map_ptr + off; + else + d.dptr = tdb1_alloc_read(tdb, off, d.dsize); + return d; +} + +/* Frees data if we're not able to simply use mmap. */ +static void put_bytes(struct tdb1_context *tdb, TDB1_DATA d) +{ + if (tdb->transaction == NULL && tdb->map_ptr != NULL) + return; + free(d.dptr); +} + +/* We use the excellent Jenkins lookup3 hash; this is based on hash_word2. + * See: http://burtleburtle.net/bob/c/lookup3.c + */ +#define rot(x,k) (((x)<<(k)) | ((x)>>(32-(k)))) +static void jhash(uint32_t key, uint32_t *pc, uint32_t *pb) +{ + uint32_t a,b,c; + + /* Set up the internal state */ + a = b = c = 0xdeadbeef + *pc; + c += *pb; + a += key; + c ^= b; c -= rot(b,14); + a ^= c; a -= rot(c,11); + b ^= a; b -= rot(a,25); + c ^= b; c -= rot(b,16); + a ^= c; a -= rot(c,4); + b ^= a; b -= rot(a,14); + c ^= b; c -= rot(b,24); + *pc=c; *pb=b; +} + +/* + We want to check that all free records are in the free list + (only once), and all free list entries are free records. Similarly + for each hash chain of used records. + + Doing that naively (without walking hash chains, since we want to be + linear) means keeping a list of records which have been seen in each + hash chain, and another of records pointed to (ie. next pointers + from records and the initial hash chain heads). These two lists + should be equal. This will take 8 bytes per record, and require + sorting at the end. + + So instead, we record each offset in a bitmap such a way that + recording it twice will cancel out. Since each offset should appear + exactly twice, the bitmap should be zero at the end. + + The approach was inspired by Bloom Filters (see Wikipedia). For + each value, we flip K bits in a bitmap of size N. The number of + distinct arrangements is: + + N! / (K! * (N-K)!) + + Of course, not all arrangements are actually distinct, but testing + shows this formula to be close enough. + + So, if K == 8 and N == 256, the probability of two things flipping the same + bits is 1 in 409,663,695,276,000. + + Given that ldb uses a hash size of 10000, using 32 bytes per hash chain + (320k) seems reasonable. +*/ +#define NUM_HASHES 8 +#define BITMAP_BITS 256 + +static void bit_flip(unsigned char bits[], unsigned int idx) +{ + bits[idx / CHAR_BIT] ^= (1 << (idx % CHAR_BIT)); +} + +/* We record offsets in a bitmap for the particular chain it should be in. */ +static void record_offset(unsigned char bits[], tdb1_off_t off) +{ + uint32_t h1 = off, h2 = 0; + unsigned int i; + + /* We get two good hash values out of jhash2, so we use both. Then + * we keep going to produce further hash values. */ + for (i = 0; i < NUM_HASHES / 2; i++) { + jhash(off, &h1, &h2); + bit_flip(bits, h1 % BITMAP_BITS); + bit_flip(bits, h2 % BITMAP_BITS); + h2++; + } +} + +/* Check that an in-use record is valid. */ +static bool tdb1_check_used_record(struct tdb1_context *tdb, + tdb1_off_t off, + const struct tdb1_record *rec, + unsigned char **hashes, + int (*check)(TDB1_DATA, TDB1_DATA, void *), + void *private_data) +{ + TDB1_DATA key, data; + + if (!tdb1_check_record(tdb, off, rec)) + return false; + + /* key + data + tailer must fit in record */ + if (rec->key_len + rec->data_len + sizeof(tdb1_off_t) > rec->rec_len) { + TDB1_LOG((tdb, TDB1_DEBUG_ERROR, + "Record offset %d too short for contents\n", off)); + return false; + } + + key = get_bytes(tdb, off + sizeof(*rec), rec->key_len); + if (!key.dptr) + return false; + + if (tdb->hash_fn(&key) != rec->full_hash) { + TDB1_LOG((tdb, TDB1_DEBUG_ERROR, + "Record offset %d has incorrect hash\n", off)); + goto fail_put_key; + } + + /* Mark this offset as a known value for this hash bucket. */ + record_offset(hashes[TDB1_BUCKET(rec->full_hash)+1], off); + /* And similarly if the next pointer is valid. */ + if (rec->next) + record_offset(hashes[TDB1_BUCKET(rec->full_hash)+1], rec->next); + + /* If they supply a check function and this record isn't dead, + get data and feed it. */ + if (check && rec->magic != TDB1_DEAD_MAGIC) { + data = get_bytes(tdb, off + sizeof(*rec) + rec->key_len, + rec->data_len); + if (!data.dptr) + goto fail_put_key; + + if (check(key, data, private_data) == -1) + goto fail_put_data; + put_bytes(tdb, data); + } + + put_bytes(tdb, key); + return true; + +fail_put_data: + put_bytes(tdb, data); +fail_put_key: + put_bytes(tdb, key); + return false; +} + +/* Check that an unused record is valid. */ +static bool tdb1_check_free_record(struct tdb1_context *tdb, + tdb1_off_t off, + const struct tdb1_record *rec, + unsigned char **hashes) +{ + if (!tdb1_check_record(tdb, off, rec)) + return false; + + /* Mark this offset as a known value for the free list. */ + record_offset(hashes[0], off); + /* And similarly if the next pointer is valid. */ + if (rec->next) + record_offset(hashes[0], rec->next); + return true; +} + +/* Slow, but should be very rare. */ +size_t tdb1_dead_space(struct tdb1_context *tdb, tdb1_off_t off) +{ + size_t len; + + for (len = 0; off + len < tdb->map_size; len++) { + char c; + if (tdb->methods->tdb1_read(tdb, off, &c, 1, 0)) + return 0; + if (c != 0 && c != 0x42) + break; + } + return len; +} + +_PUBLIC_ int tdb1_check(struct tdb1_context *tdb, + int (*check)(TDB1_DATA key, TDB1_DATA data, void *private_data), + void *private_data) +{ + unsigned int h; + unsigned char **hashes; + tdb1_off_t off, recovery_start; + struct tdb1_record rec; + bool found_recovery = false; + tdb1_len_t dead; + bool locked; + + /* Read-only databases use no locking at all: it's best-effort. + * We may have a write lock already, so skip that case too. */ + if (tdb->read_only || tdb->allrecord_lock.count != 0) { + locked = false; + } else { + if (tdb1_lockall_read(tdb) == -1) + return -1; + locked = true; + } + + /* Make sure we know true size of the underlying file. */ + tdb->methods->tdb1_oob(tdb, tdb->map_size + 1, 1); + + /* Header must be OK: also gets us the recovery ptr, if any. */ + if (!tdb1_check_header(tdb, &recovery_start)) + goto unlock; + + /* We should have the whole header, too. */ + if (tdb->map_size < TDB1_DATA_START(tdb->header.hash_size)) { + tdb->ecode = TDB1_ERR_CORRUPT; + TDB1_LOG((tdb, TDB1_DEBUG_ERROR, "File too short for hashes\n")); + goto unlock; + } + + /* One big malloc: pointers then bit arrays. */ + hashes = (unsigned char **)calloc( + 1, sizeof(hashes[0]) * (1+tdb->header.hash_size) + + BITMAP_BITS / CHAR_BIT * (1+tdb->header.hash_size)); + if (!hashes) { + tdb->ecode = TDB1_ERR_OOM; + goto unlock; + } + + /* Initialize pointers */ + hashes[0] = (unsigned char *)(&hashes[1+tdb->header.hash_size]); + for (h = 1; h < 1+tdb->header.hash_size; h++) + hashes[h] = hashes[h-1] + BITMAP_BITS / CHAR_BIT; + + /* Freelist and hash headers are all in a row: read them. */ + for (h = 0; h < 1+tdb->header.hash_size; h++) { + if (tdb1_ofs_read(tdb, TDB1_FREELIST_TOP + h*sizeof(tdb1_off_t), + &off) == -1) + goto free; + if (off) + record_offset(hashes[h], off); + } + + /* For each record, read it in and check it's ok. */ + for (off = TDB1_DATA_START(tdb->header.hash_size); + off < tdb->map_size; + off += sizeof(rec) + rec.rec_len) { + if (tdb->methods->tdb1_read(tdb, off, &rec, sizeof(rec), + TDB1_DOCONV()) == -1) + goto free; + switch (rec.magic) { + case TDB1_MAGIC: + case TDB1_DEAD_MAGIC: + if (!tdb1_check_used_record(tdb, off, &rec, hashes, + check, private_data)) + goto free; + break; + case TDB1_FREE_MAGIC: + if (!tdb1_check_free_record(tdb, off, &rec, hashes)) + goto free; + break; + /* If we crash after ftruncate, we can get zeroes or fill. */ + case TDB1_RECOVERY_INVALID_MAGIC: + case 0x42424242: + if (recovery_start == off) { + found_recovery = true; + break; + } + dead = tdb1_dead_space(tdb, off); + if (dead < sizeof(rec)) + goto corrupt; + + TDB1_LOG((tdb, TDB1_DEBUG_ERROR, + "Dead space at %d-%d (of %u)\n", + off, off + dead, tdb->map_size)); + rec.rec_len = dead - sizeof(rec); + break; + case TDB1_RECOVERY_MAGIC: + if (recovery_start != off) { + TDB1_LOG((tdb, TDB1_DEBUG_ERROR, + "Unexpected recovery record at offset %d\n", + off)); + goto free; + } + found_recovery = true; + break; + default: ; + corrupt: + tdb->ecode = TDB1_ERR_CORRUPT; + TDB1_LOG((tdb, TDB1_DEBUG_ERROR, + "Bad magic 0x%x at offset %d\n", + rec.magic, off)); + goto free; + } + } + + /* Now, hashes should all be empty: each record exists and is referred + * to by one other. */ + for (h = 0; h < 1+tdb->header.hash_size; h++) { + unsigned int i; + for (i = 0; i < BITMAP_BITS / CHAR_BIT; i++) { + if (hashes[h][i] != 0) { + tdb->ecode = TDB1_ERR_CORRUPT; + TDB1_LOG((tdb, TDB1_DEBUG_ERROR, + "Hashes do not match records\n")); + goto free; + } + } + } + + /* We must have found recovery area if there was one. */ + if (recovery_start != 0 && !found_recovery) { + TDB1_LOG((tdb, TDB1_DEBUG_ERROR, + "Expected a recovery area at %u\n", + recovery_start)); + goto free; + } + + free(hashes); + if (locked) { + tdb1_unlockall_read(tdb); + } + return 0; + +free: + free(hashes); +unlock: + if (locked) { + tdb1_unlockall_read(tdb); + } + return -1; +} diff --git a/ccan/tdb2/tdb1_dump.c b/ccan/tdb2/tdb1_dump.c new file mode 100644 index 00000000..435a7063 --- /dev/null +++ b/ccan/tdb2/tdb1_dump.c @@ -0,0 +1,136 @@ + /* + Unix SMB/CIFS implementation. + + trivial database library + + Copyright (C) Andrew Tridgell 1999-2005 + Copyright (C) Paul `Rusty' Russell 2000 + Copyright (C) Jeremy Allison 2000-2003 + + ** NOTE! The following LGPL license applies to the tdb + ** library. This does NOT imply that all of Samba is released + ** under the LGPL + + This library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 3 of the License, or (at your option) any later version. + + This library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with this library; if not, see . +*/ + +#include "tdb1_private.h" + +static tdb1_off_t tdb1_dump_record(struct tdb1_context *tdb, int hash, + tdb1_off_t offset) +{ + struct tdb1_record rec; + tdb1_off_t tailer_ofs, tailer; + + if (tdb->methods->tdb1_read(tdb, offset, (char *)&rec, + sizeof(rec), TDB1_DOCONV()) == -1) { + printf("ERROR: failed to read record at %u\n", offset); + return 0; + } + + printf(" rec: hash=%d offset=0x%08x next=0x%08x rec_len=%d " + "key_len=%d data_len=%d full_hash=0x%x magic=0x%x\n", + hash, offset, rec.next, rec.rec_len, rec.key_len, rec.data_len, + rec.full_hash, rec.magic); + + tailer_ofs = offset + sizeof(rec) + rec.rec_len - sizeof(tdb1_off_t); + + if (tdb1_ofs_read(tdb, tailer_ofs, &tailer) == -1) { + printf("ERROR: failed to read tailer at %u\n", tailer_ofs); + return rec.next; + } + + if (tailer != rec.rec_len + sizeof(rec)) { + printf("ERROR: tailer does not match record! tailer=%u totalsize=%u\n", + (unsigned int)tailer, (unsigned int)(rec.rec_len + sizeof(rec))); + } + return rec.next; +} + +static int tdb1_dump_chain(struct tdb1_context *tdb, int i) +{ + tdb1_off_t rec_ptr, top; + + top = TDB1_HASH_TOP(i); + + if (tdb1_lock(tdb, i, F_WRLCK) != 0) + return -1; + + if (tdb1_ofs_read(tdb, top, &rec_ptr) == -1) + return tdb1_unlock(tdb, i, F_WRLCK); + + if (rec_ptr) + printf("hash=%d\n", i); + + while (rec_ptr) { + rec_ptr = tdb1_dump_record(tdb, i, rec_ptr); + } + + return tdb1_unlock(tdb, i, F_WRLCK); +} + +_PUBLIC_ void tdb1_dump_all(struct tdb1_context *tdb) +{ + int i; + for (i=0;iheader.hash_size;i++) { + tdb1_dump_chain(tdb, i); + } + printf("freelist:\n"); + tdb1_dump_chain(tdb, -1); +} + +_PUBLIC_ int tdb1_printfreelist(struct tdb1_context *tdb) +{ + int ret; + long total_free = 0; + tdb1_off_t offset, rec_ptr; + struct tdb1_record rec; + + if ((ret = tdb1_lock(tdb, -1, F_WRLCK)) != 0) + return ret; + + offset = TDB1_FREELIST_TOP; + + /* read in the freelist top */ + if (tdb1_ofs_read(tdb, offset, &rec_ptr) == -1) { + tdb1_unlock(tdb, -1, F_WRLCK); + return 0; + } + + printf("freelist top=[0x%08x]\n", rec_ptr ); + while (rec_ptr) { + if (tdb->methods->tdb1_read(tdb, rec_ptr, (char *)&rec, + sizeof(rec), TDB1_DOCONV()) == -1) { + tdb1_unlock(tdb, -1, F_WRLCK); + return -1; + } + + if (rec.magic != TDB1_FREE_MAGIC) { + printf("bad magic 0x%08x in free list\n", rec.magic); + tdb1_unlock(tdb, -1, F_WRLCK); + return -1; + } + + printf("entry offset=[0x%08x], rec.rec_len = [0x%08x (%d)] (end = 0x%08x)\n", + rec_ptr, rec.rec_len, rec.rec_len, rec_ptr + rec.rec_len); + total_free += rec.rec_len; + + /* move to the next record */ + rec_ptr = rec.next; + } + printf("total rec_len = [0x%08x (%d)]\n", (int)total_free, + (int)total_free); + + return tdb1_unlock(tdb, -1, F_WRLCK); +} diff --git a/ccan/tdb2/tdb1_error.c b/ccan/tdb2/tdb1_error.c new file mode 100644 index 00000000..e5558059 --- /dev/null +++ b/ccan/tdb2/tdb1_error.c @@ -0,0 +1,56 @@ + /* + Unix SMB/CIFS implementation. + + trivial database library + + Copyright (C) Andrew Tridgell 1999-2005 + Copyright (C) Paul `Rusty' Russell 2000 + Copyright (C) Jeremy Allison 2000-2003 + + ** NOTE! The following LGPL license applies to the tdb + ** library. This does NOT imply that all of Samba is released + ** under the LGPL + + This library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 3 of the License, or (at your option) any later version. + + This library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with this library; if not, see . +*/ + +#include "tdb1_private.h" + +_PUBLIC_ enum TDB1_ERROR tdb1_error(struct tdb1_context *tdb) +{ + return tdb->ecode; +} + +static struct tdb1_errname { + enum TDB1_ERROR ecode; const char *estring; +} emap[] = { {TDB1_SUCCESS, "Success"}, + {TDB1_ERR_CORRUPT, "Corrupt database"}, + {TDB1_ERR_IO, "IO Error"}, + {TDB1_ERR_LOCK, "Locking error"}, + {TDB1_ERR_OOM, "Out of memory"}, + {TDB1_ERR_EXISTS, "Record exists"}, + {TDB1_ERR_NOLOCK, "Lock exists on other keys"}, + {TDB1_ERR_EINVAL, "Invalid parameter"}, + {TDB1_ERR_NOEXIST, "Record does not exist"}, + {TDB1_ERR_RDONLY, "write not permitted"} }; + +/* Error string for the last tdb error */ +_PUBLIC_ const char *tdb1_errorstr(struct tdb1_context *tdb) +{ + uint32_t i; + for (i = 0; i < sizeof(emap) / sizeof(struct tdb1_errname); i++) + if (tdb->ecode == emap[i].ecode) + return emap[i].estring; + return "Invalid error code"; +} diff --git a/ccan/tdb2/tdb1_freelist.c b/ccan/tdb2/tdb1_freelist.c new file mode 100644 index 00000000..9c40bc9e --- /dev/null +++ b/ccan/tdb2/tdb1_freelist.c @@ -0,0 +1,386 @@ + /* + Unix SMB/CIFS implementation. + + trivial database library + + Copyright (C) Andrew Tridgell 1999-2005 + Copyright (C) Paul `Rusty' Russell 2000 + Copyright (C) Jeremy Allison 2000-2003 + + ** NOTE! The following LGPL license applies to the tdb + ** library. This does NOT imply that all of Samba is released + ** under the LGPL + + This library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 3 of the License, or (at your option) any later version. + + This library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with this library; if not, see . +*/ + +#include "tdb1_private.h" + +/* 'right' merges can involve O(n^2) cost when combined with a + traverse, so they are disabled until we find a way to do them in + O(1) time +*/ +#define USE_RIGHT_MERGES 0 + +/* read a freelist record and check for simple errors */ +int tdb1_rec_free_read(struct tdb1_context *tdb, tdb1_off_t off, struct tdb1_record *rec) +{ + if (tdb->methods->tdb1_read(tdb, off, rec, sizeof(*rec),TDB1_DOCONV()) == -1) + return -1; + + if (rec->magic == TDB1_MAGIC) { + /* this happens when a app is showdown while deleting a record - we should + not completely fail when this happens */ + TDB1_LOG((tdb, TDB1_DEBUG_WARNING, "tdb1_rec_free_read non-free magic 0x%x at offset=%d - fixing\n", + rec->magic, off)); + rec->magic = TDB1_FREE_MAGIC; + if (tdb->methods->tdb1_write(tdb, off, rec, sizeof(*rec)) == -1) + return -1; + } + + if (rec->magic != TDB1_FREE_MAGIC) { + /* Ensure ecode is set for log fn. */ + tdb->ecode = TDB1_ERR_CORRUPT; + TDB1_LOG((tdb, TDB1_DEBUG_WARNING, "tdb1_rec_free_read bad magic 0x%x at offset=%d\n", + rec->magic, off)); + return -1; + } + if (tdb->methods->tdb1_oob(tdb, rec->next+sizeof(*rec), 0) != 0) + return -1; + return 0; +} + + +#if USE_RIGHT_MERGES +/* Remove an element from the freelist. Must have alloc lock. */ +static int remove_from_freelist(struct tdb1_context *tdb, tdb1_off_t off, tdb1_off_t next) +{ + tdb1_off_t last_ptr, i; + + /* read in the freelist top */ + last_ptr = TDB1_FREELIST_TOP; + while (tdb1_ofs_read(tdb, last_ptr, &i) != -1 && i != 0) { + if (i == off) { + /* We've found it! */ + return tdb1_ofs_write(tdb, last_ptr, &next); + } + /* Follow chain (next offset is at start of record) */ + last_ptr = i; + } + tdb->ecode = TDB1_ERR_CORRUPT; + TDB1_LOG((tdb, TDB1_DEBUG_FATAL,"remove_from_freelist: not on list at off=%d\n", off)); + return -1; +} +#endif + + +/* update a record tailer (must hold allocation lock) */ +static int update_tailer(struct tdb1_context *tdb, tdb1_off_t offset, + const struct tdb1_record *rec) +{ + tdb1_off_t totalsize; + + /* Offset of tailer from record header */ + totalsize = sizeof(*rec) + rec->rec_len; + return tdb1_ofs_write(tdb, offset + totalsize - sizeof(tdb1_off_t), + &totalsize); +} + +/* Add an element into the freelist. Merge adjacent records if + necessary. */ +int tdb1_free(struct tdb1_context *tdb, tdb1_off_t offset, struct tdb1_record *rec) +{ + /* Allocation and tailer lock */ + if (tdb1_lock(tdb, -1, F_WRLCK) != 0) + return -1; + + /* set an initial tailer, so if we fail we don't leave a bogus record */ + if (update_tailer(tdb, offset, rec) != 0) { + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "tdb1_free: update_tailer failed!\n")); + goto fail; + } + +#if USE_RIGHT_MERGES + /* Look right first (I'm an Australian, dammit) */ + if (offset + sizeof(*rec) + rec->rec_len + sizeof(*rec) <= tdb->map_size) { + tdb1_off_t right = offset + sizeof(*rec) + rec->rec_len; + struct tdb1_record r; + + if (tdb->methods->tdb1_read(tdb, right, &r, sizeof(r), TDB1_DOCONV()) == -1) { + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "tdb1_free: right read failed at %u\n", right)); + goto left; + } + + /* If it's free, expand to include it. */ + if (r.magic == TDB1_FREE_MAGIC) { + if (remove_from_freelist(tdb, right, r.next) == -1) { + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "tdb1_free: right free failed at %u\n", right)); + goto left; + } + rec->rec_len += sizeof(r) + r.rec_len; + if (update_tailer(tdb, offset, rec) == -1) { + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "tdb1_free: update_tailer failed at %u\n", offset)); + goto fail; + } + } + } +left: +#endif + + /* Look left */ + if (offset - sizeof(tdb1_off_t) > TDB1_DATA_START(tdb->header.hash_size)) { + tdb1_off_t left = offset - sizeof(tdb1_off_t); + struct tdb1_record l; + tdb1_off_t leftsize; + + /* Read in tailer and jump back to header */ + if (tdb1_ofs_read(tdb, left, &leftsize) == -1) { + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "tdb1_free: left offset read failed at %u\n", left)); + goto update; + } + + /* it could be uninitialised data */ + if (leftsize == 0 || leftsize == TDB1_PAD_U32) { + goto update; + } + + left = offset - leftsize; + + if (leftsize > offset || + left < TDB1_DATA_START(tdb->header.hash_size)) { + goto update; + } + + /* Now read in the left record */ + if (tdb->methods->tdb1_read(tdb, left, &l, sizeof(l), TDB1_DOCONV()) == -1) { + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "tdb1_free: left read failed at %u (%u)\n", left, leftsize)); + goto update; + } + + /* If it's free, expand to include it. */ + if (l.magic == TDB1_FREE_MAGIC) { + /* we now merge the new record into the left record, rather than the other + way around. This makes the operation O(1) instead of O(n). This change + prevents traverse from being O(n^2) after a lot of deletes */ + l.rec_len += sizeof(*rec) + rec->rec_len; + if (tdb1_rec_write(tdb, left, &l) == -1) { + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "tdb1_free: update_left failed at %u\n", left)); + goto fail; + } + if (update_tailer(tdb, left, &l) == -1) { + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "tdb1_free: update_tailer failed at %u\n", offset)); + goto fail; + } + tdb1_unlock(tdb, -1, F_WRLCK); + return 0; + } + } + +update: + + /* Now, prepend to free list */ + rec->magic = TDB1_FREE_MAGIC; + + if (tdb1_ofs_read(tdb, TDB1_FREELIST_TOP, &rec->next) == -1 || + tdb1_rec_write(tdb, offset, rec) == -1 || + tdb1_ofs_write(tdb, TDB1_FREELIST_TOP, &offset) == -1) { + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "tdb1_free record write failed at offset=%d\n", offset)); + goto fail; + } + + /* And we're done. */ + tdb1_unlock(tdb, -1, F_WRLCK); + return 0; + + fail: + tdb1_unlock(tdb, -1, F_WRLCK); + return -1; +} + + + +/* + the core of tdb1_allocate - called when we have decided which + free list entry to use + + Note that we try to allocate by grabbing data from the end of an existing record, + not the beginning. This is so the left merge in a free is more likely to be + able to free up the record without fragmentation + */ +static tdb1_off_t tdb1_allocate_ofs(struct tdb1_context *tdb, + tdb1_len_t length, tdb1_off_t rec_ptr, + struct tdb1_record *rec, tdb1_off_t last_ptr) +{ +#define MIN_REC_SIZE (sizeof(struct tdb1_record) + sizeof(tdb1_off_t) + 8) + + if (rec->rec_len < length + MIN_REC_SIZE) { + /* we have to grab the whole record */ + + /* unlink it from the previous record */ + if (tdb1_ofs_write(tdb, last_ptr, &rec->next) == -1) { + return 0; + } + + /* mark it not free */ + rec->magic = TDB1_MAGIC; + if (tdb1_rec_write(tdb, rec_ptr, rec) == -1) { + return 0; + } + return rec_ptr; + } + + /* we're going to just shorten the existing record */ + rec->rec_len -= (length + sizeof(*rec)); + if (tdb1_rec_write(tdb, rec_ptr, rec) == -1) { + return 0; + } + if (update_tailer(tdb, rec_ptr, rec) == -1) { + return 0; + } + + /* and setup the new record */ + rec_ptr += sizeof(*rec) + rec->rec_len; + + memset(rec, '\0', sizeof(*rec)); + rec->rec_len = length; + rec->magic = TDB1_MAGIC; + + if (tdb1_rec_write(tdb, rec_ptr, rec) == -1) { + return 0; + } + + if (update_tailer(tdb, rec_ptr, rec) == -1) { + return 0; + } + + return rec_ptr; +} + +/* allocate some space from the free list. The offset returned points + to a unconnected tdb1_record within the database with room for at + least length bytes of total data + + 0 is returned if the space could not be allocated + */ +tdb1_off_t tdb1_allocate(struct tdb1_context *tdb, tdb1_len_t length, struct tdb1_record *rec) +{ + tdb1_off_t rec_ptr, last_ptr, newrec_ptr; + struct { + tdb1_off_t rec_ptr, last_ptr; + tdb1_len_t rec_len; + } bestfit; + float multiplier = 1.0; + + if (tdb1_lock(tdb, -1, F_WRLCK) == -1) + return 0; + + /* over-allocate to reduce fragmentation */ + length *= 1.25; + + /* Extra bytes required for tailer */ + length += sizeof(tdb1_off_t); + length = TDB1_ALIGN(length, TDB1_ALIGNMENT); + + again: + last_ptr = TDB1_FREELIST_TOP; + + /* read in the freelist top */ + if (tdb1_ofs_read(tdb, TDB1_FREELIST_TOP, &rec_ptr) == -1) + goto fail; + + bestfit.rec_ptr = 0; + bestfit.last_ptr = 0; + bestfit.rec_len = 0; + + /* + this is a best fit allocation strategy. Originally we used + a first fit strategy, but it suffered from massive fragmentation + issues when faced with a slowly increasing record size. + */ + while (rec_ptr) { + if (tdb1_rec_free_read(tdb, rec_ptr, rec) == -1) { + goto fail; + } + + if (rec->rec_len >= length) { + if (bestfit.rec_ptr == 0 || + rec->rec_len < bestfit.rec_len) { + bestfit.rec_len = rec->rec_len; + bestfit.rec_ptr = rec_ptr; + bestfit.last_ptr = last_ptr; + } + } + + /* move to the next record */ + last_ptr = rec_ptr; + rec_ptr = rec->next; + + /* if we've found a record that is big enough, then + stop searching if its also not too big. The + definition of 'too big' changes as we scan + through */ + if (bestfit.rec_len > 0 && + bestfit.rec_len < length * multiplier) { + break; + } + + /* this multiplier means we only extremely rarely + search more than 50 or so records. At 50 records we + accept records up to 11 times larger than what we + want */ + multiplier *= 1.05; + } + + if (bestfit.rec_ptr != 0) { + if (tdb1_rec_free_read(tdb, bestfit.rec_ptr, rec) == -1) { + goto fail; + } + + newrec_ptr = tdb1_allocate_ofs(tdb, length, bestfit.rec_ptr, + rec, bestfit.last_ptr); + tdb1_unlock(tdb, -1, F_WRLCK); + return newrec_ptr; + } + + /* we didn't find enough space. See if we can expand the + database and if we can then try again */ + if (tdb1_expand(tdb, length + sizeof(*rec)) == 0) + goto again; + fail: + tdb1_unlock(tdb, -1, F_WRLCK); + return 0; +} + + + +/* + return the size of the freelist - used to decide if we should repack +*/ +_PUBLIC_ int tdb1_freelist_size(struct tdb1_context *tdb) +{ + tdb1_off_t ptr; + int count=0; + + if (tdb1_lock(tdb, -1, F_RDLCK) == -1) { + return -1; + } + + ptr = TDB1_FREELIST_TOP; + while (tdb1_ofs_read(tdb, ptr, &ptr) == 0 && ptr != 0) { + count++; + } + + tdb1_unlock(tdb, -1, F_RDLCK); + return count; +} diff --git a/ccan/tdb2/tdb1_freelistcheck.c b/ccan/tdb2/tdb1_freelistcheck.c new file mode 100644 index 00000000..c095ea57 --- /dev/null +++ b/ccan/tdb2/tdb1_freelistcheck.c @@ -0,0 +1,109 @@ +/* + Unix SMB/CIFS implementation. + + trivial database library + + Copyright (C) Jeremy Allison 2006 + + ** NOTE! The following LGPL license applies to the tdb + ** library. This does NOT imply that all of Samba is released + ** under the LGPL + + This library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 3 of the License, or (at your option) any later version. + + This library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with this library; if not, see . +*/ + +#include "tdb1_private.h" + +/* Check the freelist is good and contains no loops. + Very memory intensive - only do this as a consistency + checker. Heh heh - uses an in memory tdb as the storage + for the "seen" record list. For some reason this strikes + me as extremely clever as I don't have to write another tree + data structure implementation :-). + */ + +static int seen_insert(struct tdb1_context *mem_tdb, tdb1_off_t rec_ptr) +{ + TDB1_DATA key, data; + + memset(&data, '\0', sizeof(data)); + key.dptr = (unsigned char *)&rec_ptr; + key.dsize = sizeof(rec_ptr); + return tdb1_store(mem_tdb, key, data, TDB1_INSERT); +} + +_PUBLIC_ int tdb1_validate_freelist(struct tdb1_context *tdb, int *pnum_entries) +{ + struct tdb1_context *mem_tdb = NULL; + struct tdb1_record rec; + tdb1_off_t rec_ptr, last_ptr; + int ret = -1; + + *pnum_entries = 0; + + mem_tdb = tdb1_open("flval", tdb->header.hash_size, + TDB1_INTERNAL, O_RDWR, 0600); + if (!mem_tdb) { + return -1; + } + + if (tdb1_lock(tdb, -1, F_WRLCK) == -1) { + tdb1_close(mem_tdb); + return 0; + } + + last_ptr = TDB1_FREELIST_TOP; + + /* Store the TDB1_FREELIST_TOP record. */ + if (seen_insert(mem_tdb, last_ptr) == -1) { + tdb->ecode = TDB1_ERR_CORRUPT; + ret = -1; + goto fail; + } + + /* read in the freelist top */ + if (tdb1_ofs_read(tdb, TDB1_FREELIST_TOP, &rec_ptr) == -1) { + goto fail; + } + + while (rec_ptr) { + + /* If we can't store this record (we've seen it + before) then the free list has a loop and must + be corrupt. */ + + if (seen_insert(mem_tdb, rec_ptr)) { + tdb->ecode = TDB1_ERR_CORRUPT; + ret = -1; + goto fail; + } + + if (tdb1_rec_free_read(tdb, rec_ptr, &rec) == -1) { + goto fail; + } + + /* move to the next record */ + last_ptr = rec_ptr; + rec_ptr = rec.next; + *pnum_entries += 1; + } + + ret = 0; + + fail: + + tdb1_close(mem_tdb); + tdb1_unlock(tdb, -1, F_WRLCK); + return ret; +} diff --git a/ccan/tdb2/tdb1_hash.c b/ccan/tdb2/tdb1_hash.c new file mode 100644 index 00000000..8a33e8a8 --- /dev/null +++ b/ccan/tdb2/tdb1_hash.c @@ -0,0 +1,345 @@ + /* + Unix SMB/CIFS implementation. + + trivial database library + + Copyright (C) Rusty Russell 2010 + + ** NOTE! The following LGPL license applies to the tdb + ** library. This does NOT imply that all of Samba is released + ** under the LGPL + + This library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 3 of the License, or (at your option) any later version. + + This library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with this library; if not, see . +*/ +#include "tdb1_private.h" + +/* This is based on the hash algorithm from gdbm */ +unsigned int tdb1_old_hash(TDB1_DATA *key) +{ + uint32_t value; /* Used to compute the hash value. */ + uint32_t i; /* Used to cycle through random values. */ + + /* Set the initial value from the key size. */ + for (value = 0x238F13AF * key->dsize, i=0; i < key->dsize; i++) + value = (value + (key->dptr[i] << (i*5 % 24))); + + return (1103515243 * value + 12345); +} + +#ifndef WORDS_BIGENDIAN +# define HASH_LITTLE_ENDIAN 1 +# define HASH_BIG_ENDIAN 0 +#else +# define HASH_LITTLE_ENDIAN 0 +# define HASH_BIG_ENDIAN 1 +#endif + +/* +------------------------------------------------------------------------------- +lookup3.c, by Bob Jenkins, May 2006, Public Domain. + +These are functions for producing 32-bit hashes for hash table lookup. +hash_word(), hashlittle(), hashlittle2(), hashbig(), mix(), and final() +are externally useful functions. Routines to test the hash are included +if SELF_TEST is defined. You can use this free for any purpose. It's in +the public domain. It has no warranty. + +You probably want to use hashlittle(). hashlittle() and hashbig() +hash byte arrays. hashlittle() is is faster than hashbig() on +little-endian machines. Intel and AMD are little-endian machines. +On second thought, you probably want hashlittle2(), which is identical to +hashlittle() except it returns two 32-bit hashes for the price of one. +You could implement hashbig2() if you wanted but I haven't bothered here. + +If you want to find a hash of, say, exactly 7 integers, do + a = i1; b = i2; c = i3; + mix(a,b,c); + a += i4; b += i5; c += i6; + mix(a,b,c); + a += i7; + final(a,b,c); +then use c as the hash value. If you have a variable length array of +4-byte integers to hash, use hash_word(). If you have a byte array (like +a character string), use hashlittle(). If you have several byte arrays, or +a mix of things, see the comments above hashlittle(). + +Why is this so big? I read 12 bytes at a time into 3 4-byte integers, +then mix those integers. This is fast (you can do a lot more thorough +mixing with 12*3 instructions on 3 integers than you can with 3 instructions +on 1 byte), but shoehorning those bytes into integers efficiently is messy. +*/ + +#define hashsize(n) ((uint32_t)1<<(n)) +#define hashmask(n) (hashsize(n)-1) +#define rot(x,k) (((x)<<(k)) | ((x)>>(32-(k)))) + +/* +------------------------------------------------------------------------------- +mix -- mix 3 32-bit values reversibly. + +This is reversible, so any information in (a,b,c) before mix() is +still in (a,b,c) after mix(). + +If four pairs of (a,b,c) inputs are run through mix(), or through +mix() in reverse, there are at least 32 bits of the output that +are sometimes the same for one pair and different for another pair. +This was tested for: +* pairs that differed by one bit, by two bits, in any combination + of top bits of (a,b,c), or in any combination of bottom bits of + (a,b,c). +* "differ" is defined as +, -, ^, or ~^. For + and -, I transformed + the output delta to a Gray code (a^(a>>1)) so a string of 1's (as + is commonly produced by subtraction) look like a single 1-bit + difference. +* the base values were pseudorandom, all zero but one bit set, or + all zero plus a counter that starts at zero. + +Some k values for my "a-=c; a^=rot(c,k); c+=b;" arrangement that +satisfy this are + 4 6 8 16 19 4 + 9 15 3 18 27 15 + 14 9 3 7 17 3 +Well, "9 15 3 18 27 15" didn't quite get 32 bits diffing +for "differ" defined as + with a one-bit base and a two-bit delta. I +used http://burtleburtle.net/bob/hash/avalanche.html to choose +the operations, constants, and arrangements of the variables. + +This does not achieve avalanche. There are input bits of (a,b,c) +that fail to affect some output bits of (a,b,c), especially of a. The +most thoroughly mixed value is c, but it doesn't really even achieve +avalanche in c. + +This allows some parallelism. Read-after-writes are good at doubling +the number of bits affected, so the goal of mixing pulls in the opposite +direction as the goal of parallelism. I did what I could. Rotates +seem to cost as much as shifts on every machine I could lay my hands +on, and rotates are much kinder to the top and bottom bits, so I used +rotates. +------------------------------------------------------------------------------- +*/ +#define mix(a,b,c) \ +{ \ + a -= c; a ^= rot(c, 4); c += b; \ + b -= a; b ^= rot(a, 6); a += c; \ + c -= b; c ^= rot(b, 8); b += a; \ + a -= c; a ^= rot(c,16); c += b; \ + b -= a; b ^= rot(a,19); a += c; \ + c -= b; c ^= rot(b, 4); b += a; \ +} + +/* +------------------------------------------------------------------------------- +final -- final mixing of 3 32-bit values (a,b,c) into c + +Pairs of (a,b,c) values differing in only a few bits will usually +produce values of c that look totally different. This was tested for +* pairs that differed by one bit, by two bits, in any combination + of top bits of (a,b,c), or in any combination of bottom bits of + (a,b,c). +* "differ" is defined as +, -, ^, or ~^. For + and -, I transformed + the output delta to a Gray code (a^(a>>1)) so a string of 1's (as + is commonly produced by subtraction) look like a single 1-bit + difference. +* the base values were pseudorandom, all zero but one bit set, or + all zero plus a counter that starts at zero. + +These constants passed: + 14 11 25 16 4 14 24 + 12 14 25 16 4 14 24 +and these came close: + 4 8 15 26 3 22 24 + 10 8 15 26 3 22 24 + 11 8 15 26 3 22 24 +------------------------------------------------------------------------------- +*/ +#define final(a,b,c) \ +{ \ + c ^= b; c -= rot(b,14); \ + a ^= c; a -= rot(c,11); \ + b ^= a; b -= rot(a,25); \ + c ^= b; c -= rot(b,16); \ + a ^= c; a -= rot(c,4); \ + b ^= a; b -= rot(a,14); \ + c ^= b; c -= rot(b,24); \ +} + + +/* +------------------------------------------------------------------------------- +hashlittle() -- hash a variable-length key into a 32-bit value + k : the key (the unaligned variable-length array of bytes) + length : the length of the key, counting by bytes + val2 : IN: can be any 4-byte value OUT: second 32 bit hash. +Returns a 32-bit value. Every bit of the key affects every bit of +the return value. Two keys differing by one or two bits will have +totally different hash values. Note that the return value is better +mixed than val2, so use that first. + +The best hash table sizes are powers of 2. There is no need to do +mod a prime (mod is sooo slow!). If you need less than 32 bits, +use a bitmask. For example, if you need only 10 bits, do + h = (h & hashmask(10)); +In which case, the hash table should have hashsize(10) elements. + +If you are hashing n strings (uint8_t **)k, do it like this: + for (i=0, h=0; i 12) + { + a += k[0]; + b += k[1]; + c += k[2]; + mix(a,b,c); + length -= 12; + k += 3; + } + + /*----------------------------- handle the last (probably partial) block */ + k8 = (const uint8_t *)k; + switch(length) + { + case 12: c+=k[2]; b+=k[1]; a+=k[0]; break; + case 11: c+=((uint32_t)k8[10])<<16; /* fall through */ + case 10: c+=((uint32_t)k8[9])<<8; /* fall through */ + case 9 : c+=k8[8]; /* fall through */ + case 8 : b+=k[1]; a+=k[0]; break; + case 7 : b+=((uint32_t)k8[6])<<16; /* fall through */ + case 6 : b+=((uint32_t)k8[5])<<8; /* fall through */ + case 5 : b+=k8[4]; /* fall through */ + case 4 : a+=k[0]; break; + case 3 : a+=((uint32_t)k8[2])<<16; /* fall through */ + case 2 : a+=((uint32_t)k8[1])<<8; /* fall through */ + case 1 : a+=k8[0]; break; + case 0 : return c; + } + } else if (HASH_LITTLE_ENDIAN && ((u.i & 0x1) == 0)) { + const uint16_t *k = (const uint16_t *)key; /* read 16-bit chunks */ + const uint8_t *k8; + + /*--------------- all but last block: aligned reads and different mixing */ + while (length > 12) + { + a += k[0] + (((uint32_t)k[1])<<16); + b += k[2] + (((uint32_t)k[3])<<16); + c += k[4] + (((uint32_t)k[5])<<16); + mix(a,b,c); + length -= 12; + k += 6; + } + + /*----------------------------- handle the last (probably partial) block */ + k8 = (const uint8_t *)k; + switch(length) + { + case 12: c+=k[4]+(((uint32_t)k[5])<<16); + b+=k[2]+(((uint32_t)k[3])<<16); + a+=k[0]+(((uint32_t)k[1])<<16); + break; + case 11: c+=((uint32_t)k8[10])<<16; /* fall through */ + case 10: c+=k[4]; + b+=k[2]+(((uint32_t)k[3])<<16); + a+=k[0]+(((uint32_t)k[1])<<16); + break; + case 9 : c+=k8[8]; /* fall through */ + case 8 : b+=k[2]+(((uint32_t)k[3])<<16); + a+=k[0]+(((uint32_t)k[1])<<16); + break; + case 7 : b+=((uint32_t)k8[6])<<16; /* fall through */ + case 6 : b+=k[2]; + a+=k[0]+(((uint32_t)k[1])<<16); + break; + case 5 : b+=k8[4]; /* fall through */ + case 4 : a+=k[0]+(((uint32_t)k[1])<<16); + break; + case 3 : a+=((uint32_t)k8[2])<<16; /* fall through */ + case 2 : a+=k[0]; + break; + case 1 : a+=k8[0]; + break; + case 0 : return c; /* zero length requires no mixing */ + } + + } else { /* need to read the key one byte at a time */ + const uint8_t *k = (const uint8_t *)key; + + /*--------------- all but the last block: affect some 32 bits of (a,b,c) */ + while (length > 12) + { + a += k[0]; + a += ((uint32_t)k[1])<<8; + a += ((uint32_t)k[2])<<16; + a += ((uint32_t)k[3])<<24; + b += k[4]; + b += ((uint32_t)k[5])<<8; + b += ((uint32_t)k[6])<<16; + b += ((uint32_t)k[7])<<24; + c += k[8]; + c += ((uint32_t)k[9])<<8; + c += ((uint32_t)k[10])<<16; + c += ((uint32_t)k[11])<<24; + mix(a,b,c); + length -= 12; + k += 12; + } + + /*-------------------------------- last block: affect all 32 bits of (c) */ + switch(length) /* all the case statements fall through */ + { + case 12: c+=((uint32_t)k[11])<<24; + case 11: c+=((uint32_t)k[10])<<16; + case 10: c+=((uint32_t)k[9])<<8; + case 9 : c+=k[8]; + case 8 : b+=((uint32_t)k[7])<<24; + case 7 : b+=((uint32_t)k[6])<<16; + case 6 : b+=((uint32_t)k[5])<<8; + case 5 : b+=k[4]; + case 4 : a+=((uint32_t)k[3])<<24; + case 3 : a+=((uint32_t)k[2])<<16; + case 2 : a+=((uint32_t)k[1])<<8; + case 1 : a+=k[0]; + break; + case 0 : return c; + } + } + + final(a,b,c); + return c; +} + +_PUBLIC_ unsigned int tdb1_jenkins_hash(TDB1_DATA *key) +{ + return hashlittle(key->dptr, key->dsize); +} diff --git a/ccan/tdb2/tdb1_io.c b/ccan/tdb2/tdb1_io.c new file mode 100644 index 00000000..212e94ae --- /dev/null +++ b/ccan/tdb2/tdb1_io.c @@ -0,0 +1,490 @@ + /* + Unix SMB/CIFS implementation. + + trivial database library + + Copyright (C) Andrew Tridgell 1999-2005 + Copyright (C) Paul `Rusty' Russell 2000 + Copyright (C) Jeremy Allison 2000-2003 + + ** NOTE! The following LGPL license applies to the tdb + ** library. This does NOT imply that all of Samba is released + ** under the LGPL + + This library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 3 of the License, or (at your option) any later version. + + This library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with this library; if not, see . +*/ + + +#include "tdb1_private.h" +#ifndef MAX +#define MAX(a,b) ((a) > (b) ? (a) : (b)) +#endif + +/* check for an out of bounds access - if it is out of bounds then + see if the database has been expanded by someone else and expand + if necessary + note that "len" is the minimum length needed for the db +*/ +static int tdb1_oob(struct tdb1_context *tdb, tdb1_off_t len, int probe) +{ + struct stat st; + if (len <= tdb->map_size) + return 0; + if (tdb->flags & TDB1_INTERNAL) { + if (!probe) { + /* Ensure ecode is set for log fn. */ + tdb->ecode = TDB1_ERR_IO; + TDB1_LOG((tdb, TDB1_DEBUG_FATAL,"tdb1_oob len %d beyond internal malloc size %d\n", + (int)len, (int)tdb->map_size)); + } + return -1; + } + + if (fstat(tdb->fd, &st) == -1) { + tdb->ecode = TDB1_ERR_IO; + return -1; + } + + if (st.st_size < (size_t)len) { + if (!probe) { + /* Ensure ecode is set for log fn. */ + tdb->ecode = TDB1_ERR_IO; + TDB1_LOG((tdb, TDB1_DEBUG_FATAL,"tdb1_oob len %d beyond eof at %d\n", + (int)len, (int)st.st_size)); + } + return -1; + } + + /* Unmap, update size, remap */ + if (tdb1_munmap(tdb) == -1) { + tdb->ecode = TDB1_ERR_IO; + return -1; + } + tdb->map_size = st.st_size; + tdb1_mmap(tdb); + return 0; +} + +/* write a lump of data at a specified offset */ +static int tdb1_write(struct tdb1_context *tdb, tdb1_off_t off, + const void *buf, tdb1_len_t len) +{ + if (len == 0) { + return 0; + } + + if (tdb->read_only || tdb->traverse_read) { + tdb->ecode = TDB1_ERR_RDONLY; + return -1; + } + + if (tdb->methods->tdb1_oob(tdb, off + len, 0) != 0) + return -1; + + if (tdb->map_ptr) { + memcpy(off + (char *)tdb->map_ptr, buf, len); + } else { + ssize_t written = pwrite(tdb->fd, buf, len, off); + if ((written != (ssize_t)len) && (written != -1)) { + /* try once more */ + tdb->ecode = TDB1_ERR_IO; + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "tdb1_write: wrote only " + "%d of %d bytes at %d, trying once more\n", + (int)written, len, off)); + written = pwrite(tdb->fd, (const char *)buf+written, + len-written, + off+written); + } + if (written == -1) { + /* Ensure ecode is set for log fn. */ + tdb->ecode = TDB1_ERR_IO; + TDB1_LOG((tdb, TDB1_DEBUG_FATAL,"tdb1_write failed at %d " + "len=%d (%s)\n", off, len, strerror(errno))); + return -1; + } else if (written != (ssize_t)len) { + tdb->ecode = TDB1_ERR_IO; + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "tdb1_write: failed to " + "write %d bytes at %d in two attempts\n", + len, off)); + return -1; + } + } + return 0; +} + +/* Endian conversion: we only ever deal with 4 byte quantities */ +void *tdb1_convert(void *buf, uint32_t size) +{ + uint32_t i, *p = (uint32_t *)buf; + for (i = 0; i < size / 4; i++) + p[i] = TDB1_BYTEREV(p[i]); + return buf; +} + + +/* read a lump of data at a specified offset, maybe convert */ +static int tdb1_read(struct tdb1_context *tdb, tdb1_off_t off, void *buf, + tdb1_len_t len, int cv) +{ + if (tdb->methods->tdb1_oob(tdb, off + len, 0) != 0) { + return -1; + } + + if (tdb->map_ptr) { + memcpy(buf, off + (char *)tdb->map_ptr, len); + } else { + ssize_t ret = pread(tdb->fd, buf, len, off); + if (ret != (ssize_t)len) { + /* Ensure ecode is set for log fn. */ + tdb->ecode = TDB1_ERR_IO; + TDB1_LOG((tdb, TDB1_DEBUG_FATAL,"tdb1_read failed at %d " + "len=%d ret=%d (%s) map_size=%d\n", + (int)off, (int)len, (int)ret, strerror(errno), + (int)tdb->map_size)); + return -1; + } + } + if (cv) { + tdb1_convert(buf, len); + } + return 0; +} + + + +/* + do an unlocked scan of the hash table heads to find the next non-zero head. The value + will then be confirmed with the lock held +*/ +static void tdb1_next_hash_chain(struct tdb1_context *tdb, uint32_t *chain) +{ + uint32_t h = *chain; + if (tdb->map_ptr) { + for (;h < tdb->header.hash_size;h++) { + if (0 != *(uint32_t *)(TDB1_HASH_TOP(h) + (unsigned char *)tdb->map_ptr)) { + break; + } + } + } else { + uint32_t off=0; + for (;h < tdb->header.hash_size;h++) { + if (tdb1_ofs_read(tdb, TDB1_HASH_TOP(h), &off) != 0 || off != 0) { + break; + } + } + } + (*chain) = h; +} + + +int tdb1_munmap(struct tdb1_context *tdb) +{ + if (tdb->flags & TDB1_INTERNAL) + return 0; + +#if HAVE_MMAP + if (tdb->map_ptr) { + int ret; + + ret = munmap(tdb->map_ptr, tdb->map_size); + if (ret != 0) + return ret; + } +#endif + tdb->map_ptr = NULL; + return 0; +} + +void tdb1_mmap(struct tdb1_context *tdb) +{ + if (tdb->flags & TDB1_INTERNAL) + return; + +#if HAVE_MMAP + if (!(tdb->flags & TDB1_NOMMAP)) { + tdb->map_ptr = mmap(NULL, tdb->map_size, + PROT_READ|(tdb->read_only? 0:PROT_WRITE), + MAP_SHARED|MAP_FILE, tdb->fd, 0); + + /* + * NB. When mmap fails it returns MAP_FAILED *NOT* NULL !!!! + */ + + if (tdb->map_ptr == MAP_FAILED) { + tdb->map_ptr = NULL; + TDB1_LOG((tdb, TDB1_DEBUG_WARNING, "tdb1_mmap failed for size %d (%s)\n", + tdb->map_size, strerror(errno))); + } + } else { + tdb->map_ptr = NULL; + } +#else + tdb->map_ptr = NULL; +#endif +} + +/* expand a file. we prefer to use ftruncate, as that is what posix + says to use for mmap expansion */ +static int tdb1_expand_file(struct tdb1_context *tdb, tdb1_off_t size, tdb1_off_t addition) +{ + char buf[8192]; + + if (tdb->read_only || tdb->traverse_read) { + tdb->ecode = TDB1_ERR_RDONLY; + return -1; + } + + if (ftruncate(tdb->fd, size+addition) == -1) { + char b = 0; + ssize_t written = pwrite(tdb->fd, &b, 1, (size+addition) - 1); + if (written == 0) { + /* try once more, potentially revealing errno */ + written = pwrite(tdb->fd, &b, 1, (size+addition) - 1); + } + if (written == 0) { + /* again - give up, guessing errno */ + errno = ENOSPC; + } + if (written != 1) { + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "expand_file to %d failed (%s)\n", + size+addition, strerror(errno))); + return -1; + } + } + + /* now fill the file with something. This ensures that the + file isn't sparse, which would be very bad if we ran out of + disk. This must be done with write, not via mmap */ + memset(buf, TDB1_PAD_BYTE, sizeof(buf)); + while (addition) { + size_t n = addition>sizeof(buf)?sizeof(buf):addition; + ssize_t written = pwrite(tdb->fd, buf, n, size); + if (written == 0) { + /* prevent infinite loops: try _once_ more */ + written = pwrite(tdb->fd, buf, n, size); + } + if (written == 0) { + /* give up, trying to provide a useful errno */ + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "expand_file write " + "returned 0 twice: giving up!\n")); + errno = ENOSPC; + return -1; + } else if (written == -1) { + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "expand_file write of " + "%d bytes failed (%s)\n", (int)n, + strerror(errno))); + return -1; + } else if (written != n) { + TDB1_LOG((tdb, TDB1_DEBUG_WARNING, "expand_file: wrote " + "only %d of %d bytes - retrying\n", (int)written, + (int)n)); + } + addition -= written; + size += written; + } + return 0; +} + + +/* expand the database at least size bytes by expanding the underlying + file and doing the mmap again if necessary */ +int tdb1_expand(struct tdb1_context *tdb, tdb1_off_t size) +{ + struct tdb1_record rec; + tdb1_off_t offset, new_size, top_size, map_size; + + if (tdb1_lock(tdb, -1, F_WRLCK) == -1) { + TDB1_LOG((tdb, TDB1_DEBUG_ERROR, "lock failed in tdb1_expand\n")); + return -1; + } + + /* must know about any previous expansions by another process */ + tdb->methods->tdb1_oob(tdb, tdb->map_size + 1, 1); + + /* limit size in order to avoid using up huge amounts of memory for + * in memory tdbs if an oddball huge record creeps in */ + if (size > 100 * 1024) { + top_size = tdb->map_size + size * 2; + } else { + top_size = tdb->map_size + size * 100; + } + + /* always make room for at least top_size more records, and at + least 25% more space. if the DB is smaller than 100MiB, + otherwise grow it by 10% only. */ + if (tdb->map_size > 100 * 1024 * 1024) { + map_size = tdb->map_size * 1.10; + } else { + map_size = tdb->map_size * 1.25; + } + + /* Round the database up to a multiple of the page size */ + new_size = MAX(top_size, map_size); + size = TDB1_ALIGN(new_size, tdb->page_size) - tdb->map_size; + + if (!(tdb->flags & TDB1_INTERNAL)) + tdb1_munmap(tdb); + + /* + * We must ensure the file is unmapped before doing this + * to ensure consistency with systems like OpenBSD where + * writes and mmaps are not consistent. + */ + + /* expand the file itself */ + if (!(tdb->flags & TDB1_INTERNAL)) { + if (tdb->methods->tdb1_expand_file(tdb, tdb->map_size, size) != 0) + goto fail; + } + + tdb->map_size += size; + + if (tdb->flags & TDB1_INTERNAL) { + char *new_map_ptr = (char *)realloc(tdb->map_ptr, + tdb->map_size); + if (!new_map_ptr) { + tdb->map_size -= size; + goto fail; + } + tdb->map_ptr = new_map_ptr; + } else { + /* + * We must ensure the file is remapped before adding the space + * to ensure consistency with systems like OpenBSD where + * writes and mmaps are not consistent. + */ + + /* We're ok if the mmap fails as we'll fallback to read/write */ + tdb1_mmap(tdb); + } + + /* form a new freelist record */ + memset(&rec,'\0',sizeof(rec)); + rec.rec_len = size - sizeof(rec); + + /* link it into the free list */ + offset = tdb->map_size - size; + if (tdb1_free(tdb, offset, &rec) == -1) + goto fail; + + tdb1_unlock(tdb, -1, F_WRLCK); + return 0; + fail: + tdb1_unlock(tdb, -1, F_WRLCK); + return -1; +} + +/* read/write a tdb1_off_t */ +int tdb1_ofs_read(struct tdb1_context *tdb, tdb1_off_t offset, tdb1_off_t *d) +{ + return tdb->methods->tdb1_read(tdb, offset, (char*)d, sizeof(*d), TDB1_DOCONV()); +} + +int tdb1_ofs_write(struct tdb1_context *tdb, tdb1_off_t offset, tdb1_off_t *d) +{ + tdb1_off_t off = *d; + return tdb->methods->tdb1_write(tdb, offset, TDB1_CONV(off), sizeof(*d)); +} + + +/* read a lump of data, allocating the space for it */ +unsigned char *tdb1_alloc_read(struct tdb1_context *tdb, tdb1_off_t offset, tdb1_len_t len) +{ + unsigned char *buf; + + /* some systems don't like zero length malloc */ + + if (!(buf = (unsigned char *)malloc(len ? len : 1))) { + /* Ensure ecode is set for log fn. */ + tdb->ecode = TDB1_ERR_OOM; + TDB1_LOG((tdb, TDB1_DEBUG_ERROR,"tdb1_alloc_read malloc failed len=%d (%s)\n", + len, strerror(errno))); + return NULL; + } + if (tdb->methods->tdb1_read(tdb, offset, buf, len, 0) == -1) { + SAFE_FREE(buf); + return NULL; + } + return buf; +} + +/* Give a piece of tdb data to a parser */ + +int tdb1_parse_data(struct tdb1_context *tdb, TDB1_DATA key, + tdb1_off_t offset, tdb1_len_t len, + int (*parser)(TDB1_DATA key, TDB1_DATA data, + void *private_data), + void *private_data) +{ + TDB1_DATA data; + int result; + + data.dsize = len; + + if ((tdb->transaction == NULL) && (tdb->map_ptr != NULL)) { + /* + * Optimize by avoiding the malloc/memcpy/free, point the + * parser directly at the mmap area. + */ + if (tdb->methods->tdb1_oob(tdb, offset+len, 0) != 0) { + return -1; + } + data.dptr = offset + (unsigned char *)tdb->map_ptr; + return parser(key, data, private_data); + } + + if (!(data.dptr = tdb1_alloc_read(tdb, offset, len))) { + return -1; + } + + result = parser(key, data, private_data); + free(data.dptr); + return result; +} + +/* read/write a record */ +int tdb1_rec_read(struct tdb1_context *tdb, tdb1_off_t offset, struct tdb1_record *rec) +{ + if (tdb->methods->tdb1_read(tdb, offset, rec, sizeof(*rec),TDB1_DOCONV()) == -1) + return -1; + if (TDB1_BAD_MAGIC(rec)) { + /* Ensure ecode is set for log fn. */ + tdb->ecode = TDB1_ERR_CORRUPT; + TDB1_LOG((tdb, TDB1_DEBUG_FATAL,"tdb1_rec_read bad magic 0x%x at offset=%d\n", rec->magic, offset)); + return -1; + } + return tdb->methods->tdb1_oob(tdb, rec->next+sizeof(*rec), 0); +} + +int tdb1_rec_write(struct tdb1_context *tdb, tdb1_off_t offset, struct tdb1_record *rec) +{ + struct tdb1_record r = *rec; + return tdb->methods->tdb1_write(tdb, offset, TDB1_CONV(r), sizeof(r)); +} + +static const struct tdb1_methods io1_methods = { + tdb1_read, + tdb1_write, + tdb1_next_hash_chain, + tdb1_oob, + tdb1_expand_file, +}; + +/* + initialise the default methods table +*/ +void tdb1_io_init(struct tdb1_context *tdb) +{ + tdb->methods = &io1_methods; +} diff --git a/ccan/tdb2/tdb1_lock.c b/ccan/tdb2/tdb1_lock.c new file mode 100644 index 00000000..bed70ba2 --- /dev/null +++ b/ccan/tdb2/tdb1_lock.c @@ -0,0 +1,847 @@ + /* + Unix SMB/CIFS implementation. + + trivial database library + + Copyright (C) Andrew Tridgell 1999-2005 + Copyright (C) Paul `Rusty' Russell 2000 + Copyright (C) Jeremy Allison 2000-2003 + + ** NOTE! The following LGPL license applies to the tdb + ** library. This does NOT imply that all of Samba is released + ** under the LGPL + + This library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 3 of the License, or (at your option) any later version. + + This library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with this library; if not, see . +*/ + +#include "tdb1_private.h" + +_PUBLIC_ void tdb1_setalarm_sigptr(struct tdb1_context *tdb, volatile sig_atomic_t *ptr) +{ + tdb->interrupt_sig_ptr = ptr; +} + +static int fcntl_lock(struct tdb1_context *tdb, + int rw, off_t off, off_t len, bool waitflag) +{ + struct flock fl; + + fl.l_type = rw; + fl.l_whence = SEEK_SET; + fl.l_start = off; + fl.l_len = len; + fl.l_pid = 0; + + if (waitflag) + return fcntl(tdb->fd, F_SETLKW, &fl); + else + return fcntl(tdb->fd, F_SETLK, &fl); +} + +static int fcntl_unlock(struct tdb1_context *tdb, int rw, off_t off, off_t len) +{ + struct flock fl; +#if 0 /* Check they matched up locks and unlocks correctly. */ + char line[80]; + FILE *locks; + bool found = false; + + locks = fopen("/proc/locks", "r"); + + while (fgets(line, 80, locks)) { + char *p; + int type, start, l; + + /* eg. 1: FLOCK ADVISORY WRITE 2440 08:01:2180826 0 EOF */ + p = strchr(line, ':') + 1; + if (strncmp(p, " POSIX ADVISORY ", strlen(" POSIX ADVISORY "))) + continue; + p += strlen(" FLOCK ADVISORY "); + if (strncmp(p, "READ ", strlen("READ ")) == 0) + type = F_RDLCK; + else if (strncmp(p, "WRITE ", strlen("WRITE ")) == 0) + type = F_WRLCK; + else + abort(); + p += 6; + if (atoi(p) != getpid()) + continue; + p = strchr(strchr(p, ' ') + 1, ' ') + 1; + start = atoi(p); + p = strchr(p, ' ') + 1; + if (strncmp(p, "EOF", 3) == 0) + l = 0; + else + l = atoi(p) - start + 1; + + if (off == start) { + if (len != l) { + fprintf(stderr, "Len %u should be %u: %s", + (int)len, l, line); + abort(); + } + if (type != rw) { + fprintf(stderr, "Type %s wrong: %s", + rw == F_RDLCK ? "READ" : "WRITE", line); + abort(); + } + found = true; + break; + } + } + + if (!found) { + fprintf(stderr, "Unlock on %u@%u not found!\n", + (int)off, (int)len); + abort(); + } + + fclose(locks); +#endif + + fl.l_type = F_UNLCK; + fl.l_whence = SEEK_SET; + fl.l_start = off; + fl.l_len = len; + fl.l_pid = 0; + + return fcntl(tdb->fd, F_SETLKW, &fl); +} + +/* list -1 is the alloc list, otherwise a hash chain. */ +static tdb1_off_t lock_offset(int list) +{ + return TDB1_FREELIST_TOP + 4*list; +} + +/* a byte range locking function - return 0 on success + this functions locks/unlocks 1 byte at the specified offset. + + On error, errno is also set so that errors are passed back properly + through tdb1_open(). + + note that a len of zero means lock to end of file +*/ +int tdb1_brlock(struct tdb1_context *tdb, + int rw_type, tdb1_off_t offset, size_t len, + enum tdb1_lock_flags flags) +{ + int ret; + + if (tdb->flags & TDB1_NOLOCK) { + return 0; + } + + if (flags & TDB1_LOCK_MARK_ONLY) { + return 0; + } + + if ((rw_type == F_WRLCK) && (tdb->read_only || tdb->traverse_read)) { + tdb->ecode = TDB1_ERR_RDONLY; + return -1; + } + + do { + ret = fcntl_lock(tdb, rw_type, offset, len, + flags & TDB1_LOCK_WAIT); + /* Check for a sigalarm break. */ + if (ret == -1 && errno == EINTR && + tdb->interrupt_sig_ptr && + *tdb->interrupt_sig_ptr) { + break; + } + } while (ret == -1 && errno == EINTR); + + if (ret == -1) { + tdb->ecode = TDB1_ERR_LOCK; + /* Generic lock error. errno set by fcntl. + * EAGAIN is an expected return from non-blocking + * locks. */ + if (!(flags & TDB1_LOCK_PROBE) && errno != EAGAIN) { + TDB1_LOG((tdb, TDB1_DEBUG_TRACE,"tdb1_brlock failed (fd=%d) at offset %d rw_type=%d flags=%d len=%d\n", + tdb->fd, offset, rw_type, flags, (int)len)); + } + return -1; + } + return 0; +} + +int tdb1_brunlock(struct tdb1_context *tdb, + int rw_type, tdb1_off_t offset, size_t len) +{ + int ret; + + if (tdb->flags & TDB1_NOLOCK) { + return 0; + } + + do { + ret = fcntl_unlock(tdb, rw_type, offset, len); + } while (ret == -1 && errno == EINTR); + + if (ret == -1) { + TDB1_LOG((tdb, TDB1_DEBUG_TRACE,"tdb1_brunlock failed (fd=%d) at offset %d rw_type=%d len=%d\n", + tdb->fd, offset, rw_type, (int)len)); + } + return ret; +} + +/* + upgrade a read lock to a write lock. This needs to be handled in a + special way as some OSes (such as solaris) have too conservative + deadlock detection and claim a deadlock when progress can be + made. For those OSes we may loop for a while. +*/ +int tdb1_allrecord_upgrade(struct tdb1_context *tdb) +{ + int count = 1000; + + if (tdb->allrecord_lock.count != 1) { + TDB1_LOG((tdb, TDB1_DEBUG_ERROR, + "tdb1_allrecord_upgrade failed: count %u too high\n", + tdb->allrecord_lock.count)); + return -1; + } + + if (tdb->allrecord_lock.off != 1) { + TDB1_LOG((tdb, TDB1_DEBUG_ERROR, + "tdb1_allrecord_upgrade failed: already upgraded?\n")); + return -1; + } + + while (count--) { + struct timeval tv; + if (tdb1_brlock(tdb, F_WRLCK, TDB1_FREELIST_TOP, 0, + TDB1_LOCK_WAIT|TDB1_LOCK_PROBE) == 0) { + tdb->allrecord_lock.ltype = F_WRLCK; + tdb->allrecord_lock.off = 0; + return 0; + } + if (errno != EDEADLK) { + break; + } + /* sleep for as short a time as we can - more portable than usleep() */ + tv.tv_sec = 0; + tv.tv_usec = 1; + select(0, NULL, NULL, NULL, &tv); + } + TDB1_LOG((tdb, TDB1_DEBUG_TRACE,"tdb1_allrecord_upgrade failed\n")); + return -1; +} + +static struct tdb1_lock_type *tdb1_find_nestlock(struct tdb1_context *tdb, + tdb1_off_t offset) +{ + unsigned int i; + + for (i=0; inum_lockrecs; i++) { + if (tdb->lockrecs[i].off == offset) { + return &tdb->lockrecs[i]; + } + } + return NULL; +} + +/* lock an offset in the database. */ +int tdb1_nest_lock(struct tdb1_context *tdb, uint32_t offset, int ltype, + enum tdb1_lock_flags flags) +{ + struct tdb1_lock_type *new_lck; + + if (offset >= lock_offset(tdb->header.hash_size)) { + tdb->ecode = TDB1_ERR_LOCK; + TDB1_LOG((tdb, TDB1_DEBUG_ERROR,"tdb1_lock: invalid offset %u for ltype=%d\n", + offset, ltype)); + return -1; + } + if (tdb->flags & TDB1_NOLOCK) + return 0; + + new_lck = tdb1_find_nestlock(tdb, offset); + if (new_lck) { + /* + * Just increment the in-memory struct, posix locks + * don't stack. + */ + new_lck->count++; + return 0; + } + + new_lck = (struct tdb1_lock_type *)realloc( + tdb->lockrecs, + sizeof(*tdb->lockrecs) * (tdb->num_lockrecs+1)); + if (new_lck == NULL) { + errno = ENOMEM; + return -1; + } + tdb->lockrecs = new_lck; + + /* Since fcntl locks don't nest, we do a lock for the first one, + and simply bump the count for future ones */ + if (tdb1_brlock(tdb, ltype, offset, 1, flags)) { + return -1; + } + + tdb->lockrecs[tdb->num_lockrecs].off = offset; + tdb->lockrecs[tdb->num_lockrecs].count = 1; + tdb->lockrecs[tdb->num_lockrecs].ltype = ltype; + tdb->num_lockrecs++; + + return 0; +} + +static int tdb1_lock_and_recover(struct tdb1_context *tdb) +{ + int ret; + + /* We need to match locking order in transaction commit. */ + if (tdb1_brlock(tdb, F_WRLCK, TDB1_FREELIST_TOP, 0, TDB1_LOCK_WAIT)) { + return -1; + } + + if (tdb1_brlock(tdb, F_WRLCK, TDB1_OPEN_LOCK, 1, TDB1_LOCK_WAIT)) { + tdb1_brunlock(tdb, F_WRLCK, TDB1_FREELIST_TOP, 0); + return -1; + } + + ret = tdb1_transaction_recover(tdb); + + tdb1_brunlock(tdb, F_WRLCK, TDB1_OPEN_LOCK, 1); + tdb1_brunlock(tdb, F_WRLCK, TDB1_FREELIST_TOP, 0); + + return ret; +} + +static bool have_data_locks(const struct tdb1_context *tdb) +{ + unsigned int i; + + for (i = 0; i < tdb->num_lockrecs; i++) { + if (tdb->lockrecs[i].off >= lock_offset(-1)) + return true; + } + return false; +} + +static int tdb1_lock_list(struct tdb1_context *tdb, int list, int ltype, + enum tdb1_lock_flags waitflag) +{ + int ret; + bool check = false; + + /* a allrecord lock allows us to avoid per chain locks */ + if (tdb->allrecord_lock.count && + (ltype == tdb->allrecord_lock.ltype || ltype == F_RDLCK)) { + return 0; + } + + if (tdb->allrecord_lock.count) { + tdb->ecode = TDB1_ERR_LOCK; + ret = -1; + } else { + /* Only check when we grab first data lock. */ + check = !have_data_locks(tdb); + ret = tdb1_nest_lock(tdb, lock_offset(list), ltype, waitflag); + + if (ret == 0 && check && tdb1_needs_recovery(tdb)) { + tdb1_nest_unlock(tdb, lock_offset(list), ltype, false); + + if (tdb1_lock_and_recover(tdb) == -1) { + return -1; + } + return tdb1_lock_list(tdb, list, ltype, waitflag); + } + } + return ret; +} + +/* lock a list in the database. list -1 is the alloc list */ +int tdb1_lock(struct tdb1_context *tdb, int list, int ltype) +{ + int ret; + + ret = tdb1_lock_list(tdb, list, ltype, TDB1_LOCK_WAIT); + if (ret) { + TDB1_LOG((tdb, TDB1_DEBUG_ERROR, "tdb1_lock failed on list %d " + "ltype=%d (%s)\n", list, ltype, strerror(errno))); + } + return ret; +} + +/* lock a list in the database. list -1 is the alloc list. non-blocking lock */ +int tdb1_lock_nonblock(struct tdb1_context *tdb, int list, int ltype) +{ + return tdb1_lock_list(tdb, list, ltype, TDB1_LOCK_NOWAIT); +} + + +int tdb1_nest_unlock(struct tdb1_context *tdb, uint32_t offset, int ltype, + bool mark_lock) +{ + int ret = -1; + struct tdb1_lock_type *lck; + + if (tdb->flags & TDB1_NOLOCK) + return 0; + + /* Sanity checks */ + if (offset >= lock_offset(tdb->header.hash_size)) { + TDB1_LOG((tdb, TDB1_DEBUG_ERROR, "tdb1_unlock: offset %u invalid (%d)\n", offset, tdb->header.hash_size)); + return ret; + } + + lck = tdb1_find_nestlock(tdb, offset); + if ((lck == NULL) || (lck->count == 0)) { + TDB1_LOG((tdb, TDB1_DEBUG_ERROR, "tdb1_unlock: count is 0\n")); + return -1; + } + + if (lck->count > 1) { + lck->count--; + return 0; + } + + /* + * This lock has count==1 left, so we need to unlock it in the + * kernel. We don't bother with decrementing the in-memory array + * element, we're about to overwrite it with the last array element + * anyway. + */ + + if (mark_lock) { + ret = 0; + } else { + ret = tdb1_brunlock(tdb, ltype, offset, 1); + } + + /* + * Shrink the array by overwriting the element just unlocked with the + * last array element. + */ + *lck = tdb->lockrecs[--tdb->num_lockrecs]; + + /* + * We don't bother with realloc when the array shrinks, but if we have + * a completely idle tdb we should get rid of the locked array. + */ + + if (tdb->num_lockrecs == 0) { + SAFE_FREE(tdb->lockrecs); + } + + if (ret) + TDB1_LOG((tdb, TDB1_DEBUG_ERROR, "tdb1_unlock: An error occurred unlocking!\n")); + return ret; +} + +int tdb1_unlock(struct tdb1_context *tdb, int list, int ltype) +{ + /* a global lock allows us to avoid per chain locks */ + if (tdb->allrecord_lock.count && + (ltype == tdb->allrecord_lock.ltype || ltype == F_RDLCK)) { + return 0; + } + + if (tdb->allrecord_lock.count) { + tdb->ecode = TDB1_ERR_LOCK; + return -1; + } + + return tdb1_nest_unlock(tdb, lock_offset(list), ltype, false); +} + +/* + get the transaction lock + */ +int tdb1_transaction_lock(struct tdb1_context *tdb, int ltype, + enum tdb1_lock_flags lockflags) +{ + return tdb1_nest_lock(tdb, TDB1_TRANSACTION_LOCK, ltype, lockflags); +} + +/* + release the transaction lock + */ +int tdb1_transaction_unlock(struct tdb1_context *tdb, int ltype) +{ + return tdb1_nest_unlock(tdb, TDB1_TRANSACTION_LOCK, ltype, false); +} + +/* Returns 0 if all done, -1 if error, 1 if ok. */ +static int tdb1_allrecord_check(struct tdb1_context *tdb, int ltype, + enum tdb1_lock_flags flags, bool upgradable) +{ + /* There are no locks on read-only dbs */ + if (tdb->read_only || tdb->traverse_read) { + tdb->ecode = TDB1_ERR_LOCK; + return -1; + } + + if (tdb->allrecord_lock.count && tdb->allrecord_lock.ltype == ltype) { + tdb->allrecord_lock.count++; + return 0; + } + + if (tdb->allrecord_lock.count) { + /* a global lock of a different type exists */ + tdb->ecode = TDB1_ERR_LOCK; + return -1; + } + + if (tdb1_have_extra_locks(tdb)) { + /* can't combine global and chain locks */ + tdb->ecode = TDB1_ERR_LOCK; + return -1; + } + + if (upgradable && ltype != F_RDLCK) { + /* tdb error: you can't upgrade a write lock! */ + tdb->ecode = TDB1_ERR_LOCK; + return -1; + } + return 1; +} + +/* We only need to lock individual bytes, but Linux merges consecutive locks + * so we lock in contiguous ranges. */ +static int tdb1_chainlock_gradual(struct tdb1_context *tdb, + int ltype, enum tdb1_lock_flags flags, + size_t off, size_t len) +{ + int ret; + enum tdb1_lock_flags nb_flags = (flags & ~TDB1_LOCK_WAIT); + + if (len <= 4) { + /* Single record. Just do blocking lock. */ + return tdb1_brlock(tdb, ltype, off, len, flags); + } + + /* First we try non-blocking. */ + ret = tdb1_brlock(tdb, ltype, off, len, nb_flags); + if (ret == 0) { + return 0; + } + + /* Try locking first half, then second. */ + ret = tdb1_chainlock_gradual(tdb, ltype, flags, off, len / 2); + if (ret == -1) + return -1; + + ret = tdb1_chainlock_gradual(tdb, ltype, flags, + off + len / 2, len - len / 2); + if (ret == -1) { + tdb1_brunlock(tdb, ltype, off, len / 2); + return -1; + } + return 0; +} + +/* lock/unlock entire database. It can only be upgradable if you have some + * other way of guaranteeing exclusivity (ie. transaction write lock). + * We do the locking gradually to avoid being starved by smaller locks. */ +int tdb1_allrecord_lock(struct tdb1_context *tdb, int ltype, + enum tdb1_lock_flags flags, bool upgradable) +{ + switch (tdb1_allrecord_check(tdb, ltype, flags, upgradable)) { + case -1: + return -1; + case 0: + return 0; + } + + /* We cover two kinds of locks: + * 1) Normal chain locks. Taken for almost all operations. + * 3) Individual records locks. Taken after normal or free + * chain locks. + * + * It is (1) which cause the starvation problem, so we're only + * gradual for that. */ + if (tdb1_chainlock_gradual(tdb, ltype, flags, TDB1_FREELIST_TOP, + tdb->header.hash_size * 4) == -1) { + return -1; + } + + /* Grab individual record locks. */ + if (tdb1_brlock(tdb, ltype, lock_offset(tdb->header.hash_size), 0, + flags) == -1) { + tdb1_brunlock(tdb, ltype, TDB1_FREELIST_TOP, + tdb->header.hash_size * 4); + return -1; + } + + tdb->allrecord_lock.count = 1; + /* If it's upgradable, it's actually exclusive so we can treat + * it as a write lock. */ + tdb->allrecord_lock.ltype = upgradable ? F_WRLCK : ltype; + tdb->allrecord_lock.off = upgradable; + + if (tdb1_needs_recovery(tdb)) { + bool mark = flags & TDB1_LOCK_MARK_ONLY; + tdb1_allrecord_unlock(tdb, ltype, mark); + if (mark) { + tdb->ecode = TDB1_ERR_LOCK; + TDB1_LOG((tdb, TDB1_DEBUG_ERROR, + "tdb1_lockall_mark cannot do recovery\n")); + return -1; + } + if (tdb1_lock_and_recover(tdb) == -1) { + return -1; + } + return tdb1_allrecord_lock(tdb, ltype, flags, upgradable); + } + + return 0; +} + + + +/* unlock entire db */ +int tdb1_allrecord_unlock(struct tdb1_context *tdb, int ltype, bool mark_lock) +{ + /* There are no locks on read-only dbs */ + if (tdb->read_only || tdb->traverse_read) { + tdb->ecode = TDB1_ERR_LOCK; + return -1; + } + + if (tdb->allrecord_lock.count == 0) { + tdb->ecode = TDB1_ERR_LOCK; + return -1; + } + + /* Upgradable locks are marked as write locks. */ + if (tdb->allrecord_lock.ltype != ltype + && (!tdb->allrecord_lock.off || ltype != F_RDLCK)) { + tdb->ecode = TDB1_ERR_LOCK; + return -1; + } + + if (tdb->allrecord_lock.count > 1) { + tdb->allrecord_lock.count--; + return 0; + } + + if (!mark_lock && tdb1_brunlock(tdb, ltype, TDB1_FREELIST_TOP, 0)) { + TDB1_LOG((tdb, TDB1_DEBUG_ERROR, "tdb1_unlockall failed (%s)\n", strerror(errno))); + return -1; + } + + tdb->allrecord_lock.count = 0; + tdb->allrecord_lock.ltype = 0; + + return 0; +} + +/* lock entire database with write lock */ +_PUBLIC_ int tdb1_lockall(struct tdb1_context *tdb) +{ + return tdb1_allrecord_lock(tdb, F_WRLCK, TDB1_LOCK_WAIT, false); +} + +/* lock entire database with write lock - mark only */ +_PUBLIC_ int tdb1_lockall_mark(struct tdb1_context *tdb) +{ + return tdb1_allrecord_lock(tdb, F_WRLCK, TDB1_LOCK_MARK_ONLY, false); +} + +/* unlock entire database with write lock - unmark only */ +_PUBLIC_ int tdb1_lockall_unmark(struct tdb1_context *tdb) +{ + return tdb1_allrecord_unlock(tdb, F_WRLCK, true); +} + +/* lock entire database with write lock - nonblocking varient */ +_PUBLIC_ int tdb1_lockall_nonblock(struct tdb1_context *tdb) +{ + int ret = tdb1_allrecord_lock(tdb, F_WRLCK, TDB1_LOCK_NOWAIT, false); + return ret; +} + +/* unlock entire database with write lock */ +_PUBLIC_ int tdb1_unlockall(struct tdb1_context *tdb) +{ + return tdb1_allrecord_unlock(tdb, F_WRLCK, false); +} + +/* lock entire database with read lock */ +_PUBLIC_ int tdb1_lockall_read(struct tdb1_context *tdb) +{ + return tdb1_allrecord_lock(tdb, F_RDLCK, TDB1_LOCK_WAIT, false); +} + +/* lock entire database with read lock - nonblock varient */ +_PUBLIC_ int tdb1_lockall_read_nonblock(struct tdb1_context *tdb) +{ + int ret = tdb1_allrecord_lock(tdb, F_RDLCK, TDB1_LOCK_NOWAIT, false); + return ret; +} + +/* unlock entire database with read lock */ +_PUBLIC_ int tdb1_unlockall_read(struct tdb1_context *tdb) +{ + return tdb1_allrecord_unlock(tdb, F_RDLCK, false); +} + +/* lock/unlock one hash chain. This is meant to be used to reduce + contention - it cannot guarantee how many records will be locked */ +_PUBLIC_ int tdb1_chainlock(struct tdb1_context *tdb, TDB1_DATA key) +{ + int ret = tdb1_lock(tdb, TDB1_BUCKET(tdb->hash_fn(&key)), F_WRLCK); + return ret; +} + +/* lock/unlock one hash chain, non-blocking. This is meant to be used + to reduce contention - it cannot guarantee how many records will be + locked */ +_PUBLIC_ int tdb1_chainlock_nonblock(struct tdb1_context *tdb, TDB1_DATA key) +{ + int ret = tdb1_lock_nonblock(tdb, TDB1_BUCKET(tdb->hash_fn(&key)), F_WRLCK); + return ret; +} + +/* mark a chain as locked without actually locking it. Warning! use with great caution! */ +_PUBLIC_ int tdb1_chainlock_mark(struct tdb1_context *tdb, TDB1_DATA key) +{ + int ret = tdb1_nest_lock(tdb, lock_offset(TDB1_BUCKET(tdb->hash_fn(&key))), + F_WRLCK, TDB1_LOCK_MARK_ONLY); + return ret; +} + +/* unmark a chain as locked without actually locking it. Warning! use with great caution! */ +_PUBLIC_ int tdb1_chainlock_unmark(struct tdb1_context *tdb, TDB1_DATA key) +{ + return tdb1_nest_unlock(tdb, lock_offset(TDB1_BUCKET(tdb->hash_fn(&key))), + F_WRLCK, true); +} + +_PUBLIC_ int tdb1_chainunlock(struct tdb1_context *tdb, TDB1_DATA key) +{ + return tdb1_unlock(tdb, TDB1_BUCKET(tdb->hash_fn(&key)), F_WRLCK); +} + +_PUBLIC_ int tdb1_chainlock_read(struct tdb1_context *tdb, TDB1_DATA key) +{ + int ret; + ret = tdb1_lock(tdb, TDB1_BUCKET(tdb->hash_fn(&key)), F_RDLCK); + return ret; +} + +_PUBLIC_ int tdb1_chainunlock_read(struct tdb1_context *tdb, TDB1_DATA key) +{ + return tdb1_unlock(tdb, TDB1_BUCKET(tdb->hash_fn(&key)), F_RDLCK); +} + +/* record lock stops delete underneath */ +int tdb1_lock_record(struct tdb1_context *tdb, tdb1_off_t off) +{ + if (tdb->allrecord_lock.count) { + return 0; + } + return off ? tdb1_brlock(tdb, F_RDLCK, off, 1, TDB1_LOCK_WAIT) : 0; +} + +/* + Write locks override our own fcntl readlocks, so check it here. + Note this is meant to be F_SETLK, *not* F_SETLKW, as it's not + an error to fail to get the lock here. +*/ +int tdb1_write_lock_record(struct tdb1_context *tdb, tdb1_off_t off) +{ + struct tdb1_traverse_lock *i; + for (i = &tdb->travlocks; i; i = i->next) + if (i->off == off) + return -1; + if (tdb->allrecord_lock.count) { + if (tdb->allrecord_lock.ltype == F_WRLCK) { + return 0; + } + return -1; + } + return tdb1_brlock(tdb, F_WRLCK, off, 1, TDB1_LOCK_NOWAIT|TDB1_LOCK_PROBE); +} + +int tdb1_write_unlock_record(struct tdb1_context *tdb, tdb1_off_t off) +{ + if (tdb->allrecord_lock.count) { + return 0; + } + return tdb1_brunlock(tdb, F_WRLCK, off, 1); +} + +/* fcntl locks don't stack: avoid unlocking someone else's */ +int tdb1_unlock_record(struct tdb1_context *tdb, tdb1_off_t off) +{ + struct tdb1_traverse_lock *i; + uint32_t count = 0; + + if (tdb->allrecord_lock.count) { + return 0; + } + + if (off == 0) + return 0; + for (i = &tdb->travlocks; i; i = i->next) + if (i->off == off) + count++; + return (count == 1 ? tdb1_brunlock(tdb, F_RDLCK, off, 1) : 0); +} + +bool tdb1_have_extra_locks(struct tdb1_context *tdb) +{ + unsigned int extra = tdb->num_lockrecs; + + /* A transaction holds the lock for all records. */ + if (!tdb->transaction && tdb->allrecord_lock.count) { + return true; + } + + /* We always hold the active lock if CLEAR_IF_FIRST. */ + if (tdb1_find_nestlock(tdb, TDB1_ACTIVE_LOCK)) { + extra--; + } + + /* In a transaction, we expect to hold the transaction lock */ + if (tdb->transaction + && tdb1_find_nestlock(tdb, TDB1_TRANSACTION_LOCK)) { + extra--; + } + + return extra; +} + +/* The transaction code uses this to remove all locks. */ +void tdb1_release_transaction_locks(struct tdb1_context *tdb) +{ + unsigned int i, active = 0; + + if (tdb->allrecord_lock.count != 0) { + tdb1_brunlock(tdb, tdb->allrecord_lock.ltype, TDB1_FREELIST_TOP, 0); + tdb->allrecord_lock.count = 0; + } + + for (i=0;inum_lockrecs;i++) { + struct tdb1_lock_type *lck = &tdb->lockrecs[i]; + + /* Don't release the active lock! Copy it to first entry. */ + if (lck->off == TDB1_ACTIVE_LOCK) { + tdb->lockrecs[active++] = *lck; + } else { + tdb1_brunlock(tdb, lck->ltype, lck->off, 1); + } + } + tdb->num_lockrecs = active; + if (tdb->num_lockrecs == 0) { + SAFE_FREE(tdb->lockrecs); + } +} diff --git a/ccan/tdb2/tdb1_open.c b/ccan/tdb2/tdb1_open.c new file mode 100644 index 00000000..e7dbddd9 --- /dev/null +++ b/ccan/tdb2/tdb1_open.c @@ -0,0 +1,609 @@ + /* + Unix SMB/CIFS implementation. + + trivial database library + + Copyright (C) Andrew Tridgell 1999-2005 + Copyright (C) Paul `Rusty' Russell 2000 + Copyright (C) Jeremy Allison 2000-2003 + + ** NOTE! The following LGPL license applies to the tdb + ** library. This does NOT imply that all of Samba is released + ** under the LGPL + + This library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 3 of the License, or (at your option) any later version. + + This library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with this library; if not, see . +*/ + +#include "tdb1_private.h" + +/* all contexts, to ensure no double-opens (fcntl locks don't nest!) */ +static struct tdb1_context *tdb1s = NULL; + +/* We use two hashes to double-check they're using the right hash function. */ +void tdb1_header_hash(struct tdb1_context *tdb, + uint32_t *magic1_hash, uint32_t *magic2_hash) +{ + TDB1_DATA hash_key; + uint32_t tdb1_magic = TDB1_MAGIC; + + hash_key.dptr = (unsigned char *)TDB1_MAGIC_FOOD; + hash_key.dsize = sizeof(TDB1_MAGIC_FOOD); + *magic1_hash = tdb->hash_fn(&hash_key); + + hash_key.dptr = (unsigned char *)TDB1_CONV(tdb1_magic); + hash_key.dsize = sizeof(tdb1_magic); + *magic2_hash = tdb->hash_fn(&hash_key); + + /* Make sure at least one hash is non-zero! */ + if (*magic1_hash == 0 && *magic2_hash == 0) + *magic1_hash = 1; +} + +/* initialise a new database with a specified hash size */ +static int tdb1_new_database(struct tdb1_context *tdb, int hash_size) +{ + struct tdb1_header *newdb; + size_t size; + int ret = -1; + + /* We make it up in memory, then write it out if not internal */ + size = sizeof(struct tdb1_header) + (hash_size+1)*sizeof(tdb1_off_t); + if (!(newdb = (struct tdb1_header *)calloc(size, 1))) { + tdb->ecode = TDB1_ERR_OOM; + return -1; + } + + /* Fill in the header */ + newdb->version = TDB1_VERSION; + newdb->hash_size = hash_size; + + tdb1_header_hash(tdb, &newdb->magic1_hash, &newdb->magic2_hash); + + /* Make sure older tdbs (which don't check the magic hash fields) + * will refuse to open this TDB. */ + if (tdb->flags & TDB1_INCOMPATIBLE_HASH) + newdb->rwlocks = TDB1_HASH_RWLOCK_MAGIC; + + if (tdb->flags & TDB1_INTERNAL) { + tdb->map_size = size; + tdb->map_ptr = (char *)newdb; + memcpy(&tdb->header, newdb, sizeof(tdb->header)); + /* Convert the `ondisk' version if asked. */ + TDB1_CONV(*newdb); + return 0; + } + if (lseek(tdb->fd, 0, SEEK_SET) == -1) + goto fail; + + if (ftruncate(tdb->fd, 0) == -1) + goto fail; + + /* This creates an endian-converted header, as if read from disk */ + TDB1_CONV(*newdb); + memcpy(&tdb->header, newdb, sizeof(tdb->header)); + /* Don't endian-convert the magic food! */ + memcpy(newdb->magic_food, TDB1_MAGIC_FOOD, strlen(TDB1_MAGIC_FOOD)+1); + /* we still have "ret == -1" here */ + if (tdb1_write_all(tdb->fd, newdb, size)) + ret = 0; + + fail: + SAFE_FREE(newdb); + return ret; +} + + + +static int tdb1_already_open(dev_t device, + ino_t ino) +{ + struct tdb1_context *i; + + for (i = tdb1s; i; i = i->next) { + if (i->device == device && i->inode == ino) { + return 1; + } + } + + return 0; +} + +/* open the database, creating it if necessary + + The open_flags and mode are passed straight to the open call on the + database file. A flags value of O_WRONLY is invalid. The hash size + is advisory, use zero for a default value. + + Return is NULL on error, in which case errno is also set. Don't + try to call tdb1_error or tdb1_errname, just do strerror(errno). + + @param name may be NULL for internal databases. */ +_PUBLIC_ struct tdb1_context *tdb1_open(const char *name, int hash_size, int tdb1_flags, + int open_flags, mode_t mode) +{ + return tdb1_open_ex(name, hash_size, tdb1_flags, open_flags, mode, NULL, NULL); +} + +/* a default logging function */ +static void null_log_fn(struct tdb1_context *tdb, enum tdb1_debug_level level, const char *fmt, ...) PRINTF_ATTRIBUTE(3, 4); +static void null_log_fn(struct tdb1_context *tdb, enum tdb1_debug_level level, const char *fmt, ...) +{ +} + +static bool check_header_hash(struct tdb1_context *tdb, + bool default_hash, uint32_t *m1, uint32_t *m2) +{ + tdb1_header_hash(tdb, m1, m2); + if (tdb->header.magic1_hash == *m1 && + tdb->header.magic2_hash == *m2) { + return true; + } + + /* If they explicitly set a hash, always respect it. */ + if (!default_hash) + return false; + + /* Otherwise, try the other inbuilt hash. */ + if (tdb->hash_fn == tdb1_old_hash) + tdb->hash_fn = tdb1_jenkins_hash; + else + tdb->hash_fn = tdb1_old_hash; + return check_header_hash(tdb, false, m1, m2); +} + +_PUBLIC_ struct tdb1_context *tdb1_open_ex(const char *name, int hash_size, int tdb1_flags, + int open_flags, mode_t mode, + const struct tdb1_logging_context *log_ctx, + tdb1_hash_func hash_fn) +{ + struct tdb1_context *tdb; + struct stat st; + int rev = 0, locked = 0; + unsigned char *vp; + uint32_t vertest; + unsigned v; + const char *hash_alg; + uint32_t magic1, magic2; + + if (!(tdb = (struct tdb1_context *)calloc(1, sizeof *tdb))) { + /* Can't log this */ + errno = ENOMEM; + goto fail; + } + tdb1_io_init(tdb); + tdb->fd = -1; + tdb->name = NULL; + tdb->map_ptr = NULL; + tdb->flags = tdb1_flags; + tdb->open_flags = open_flags; + if (log_ctx) { + tdb->log = *log_ctx; + } else { + tdb->log.log_fn = null_log_fn; + tdb->log.log_private = NULL; + } + + if (name == NULL && (tdb1_flags & TDB1_INTERNAL)) { + name = "__TDB1_INTERNAL__"; + } + + if (name == NULL) { + tdb->name = (char *)"__NULL__"; + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "tdb1_open_ex: called with name == NULL\n")); + tdb->name = NULL; + errno = EINVAL; + goto fail; + } + + /* now make a copy of the name, as the caller memory might went away */ + if (!(tdb->name = (char *)strdup(name))) { + /* + * set the name as the given string, so that tdb1_name() will + * work in case of an error. + */ + tdb->name = (char *)name; + TDB1_LOG((tdb, TDB1_DEBUG_ERROR, "tdb1_open_ex: can't strdup(%s)\n", + name)); + tdb->name = NULL; + errno = ENOMEM; + goto fail; + } + + if (hash_fn) { + tdb->hash_fn = hash_fn; + hash_alg = "the user defined"; + } else { + /* This controls what we use when creating a tdb. */ + if (tdb->flags & TDB1_INCOMPATIBLE_HASH) { + tdb->hash_fn = tdb1_jenkins_hash; + } else { + tdb->hash_fn = tdb1_old_hash; + } + hash_alg = "either default"; + } + + /* cache the page size */ + tdb->page_size = getpagesize(); + if (tdb->page_size <= 0) { + tdb->page_size = 0x2000; + } + + tdb->max_dead_records = (tdb1_flags & TDB1_VOLATILE) ? 5 : 0; + + if ((open_flags & O_ACCMODE) == O_WRONLY) { + TDB1_LOG((tdb, TDB1_DEBUG_ERROR, "tdb1_open_ex: can't open tdb %s write-only\n", + name)); + errno = EINVAL; + goto fail; + } + + if (hash_size == 0) + hash_size = TDB1_DEFAULT_HASH_SIZE; + if ((open_flags & O_ACCMODE) == O_RDONLY) { + tdb->read_only = 1; + /* read only databases don't do locking or clear if first */ + tdb->flags |= TDB1_NOLOCK; + tdb->flags &= ~TDB1_CLEAR_IF_FIRST; + } + + if ((tdb->flags & TDB1_ALLOW_NESTING) && + (tdb->flags & TDB1_DISALLOW_NESTING)) { + tdb->ecode = TDB1_ERR_NESTING; + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "tdb1_open_ex: " + "allow_nesting and disallow_nesting are not allowed together!")); + errno = EINVAL; + goto fail; + } + + if (getenv("TDB_NO_FSYNC")) { + tdb->flags |= TDB1_NOSYNC; + } + + /* + * TDB1_ALLOW_NESTING is the default behavior. + * Note: this may change in future versions! + */ + if (!(tdb->flags & TDB1_DISALLOW_NESTING)) { + tdb->flags |= TDB1_ALLOW_NESTING; + } + + /* internal databases don't mmap or lock, and start off cleared */ + if (tdb->flags & TDB1_INTERNAL) { + tdb->flags |= (TDB1_NOLOCK | TDB1_NOMMAP); + tdb->flags &= ~TDB1_CLEAR_IF_FIRST; + if (tdb1_new_database(tdb, hash_size) != 0) { + TDB1_LOG((tdb, TDB1_DEBUG_ERROR, "tdb1_open_ex: tdb1_new_database failed!")); + goto fail; + } + goto internal; + } + + if ((tdb->fd = open(name, open_flags, mode)) == -1) { + TDB1_LOG((tdb, TDB1_DEBUG_WARNING, "tdb1_open_ex: could not open file %s: %s\n", + name, strerror(errno))); + goto fail; /* errno set by open(2) */ + } + + /* on exec, don't inherit the fd */ + v = fcntl(tdb->fd, F_GETFD, 0); + fcntl(tdb->fd, F_SETFD, v | FD_CLOEXEC); + + /* ensure there is only one process initialising at once */ + if (tdb1_nest_lock(tdb, TDB1_OPEN_LOCK, F_WRLCK, TDB1_LOCK_WAIT) == -1) { + TDB1_LOG((tdb, TDB1_DEBUG_ERROR, "tdb1_open_ex: failed to get open lock on %s: %s\n", + name, strerror(errno))); + goto fail; /* errno set by tdb1_brlock */ + } + + /* we need to zero database if we are the only one with it open */ + if ((tdb1_flags & TDB1_CLEAR_IF_FIRST) && + (!tdb->read_only) && + (locked = (tdb1_nest_lock(tdb, TDB1_ACTIVE_LOCK, F_WRLCK, TDB1_LOCK_NOWAIT|TDB1_LOCK_PROBE) == 0))) { + open_flags |= O_CREAT; + if (ftruncate(tdb->fd, 0) == -1) { + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "tdb1_open_ex: " + "failed to truncate %s: %s\n", + name, strerror(errno))); + goto fail; /* errno set by ftruncate */ + } + } + + errno = 0; + if (read(tdb->fd, &tdb->header, sizeof(tdb->header)) != sizeof(tdb->header) + || strcmp(tdb->header.magic_food, TDB1_MAGIC_FOOD) != 0) { + if (!(open_flags & O_CREAT) || tdb1_new_database(tdb, hash_size) == -1) { + if (errno == 0) { + errno = EIO; /* ie bad format or something */ + } + goto fail; + } + rev = (tdb->flags & TDB1_CONVERT); + } else if (tdb->header.version != TDB1_VERSION + && !(rev = (tdb->header.version==TDB1_BYTEREV(TDB1_VERSION)))) { + /* wrong version */ + errno = EIO; + goto fail; + } + vp = (unsigned char *)&tdb->header.version; + vertest = (((uint32_t)vp[0]) << 24) | (((uint32_t)vp[1]) << 16) | + (((uint32_t)vp[2]) << 8) | (uint32_t)vp[3]; + tdb->flags |= (vertest==TDB1_VERSION) ? TDB1_BIGENDIAN : 0; + if (!rev) + tdb->flags &= ~TDB1_CONVERT; + else { + tdb->flags |= TDB1_CONVERT; + tdb1_convert(&tdb->header, sizeof(tdb->header)); + } + if (fstat(tdb->fd, &st) == -1) + goto fail; + + if (tdb->header.rwlocks != 0 && + tdb->header.rwlocks != TDB1_HASH_RWLOCK_MAGIC) { + TDB1_LOG((tdb, TDB1_DEBUG_ERROR, "tdb1_open_ex: spinlocks no longer supported\n")); + goto fail; + } + + if ((tdb->header.magic1_hash == 0) && (tdb->header.magic2_hash == 0)) { + /* older TDB without magic hash references */ + tdb->hash_fn = tdb1_old_hash; + } else if (!check_header_hash(tdb, !hash_fn, &magic1, &magic2)) { + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "tdb1_open_ex: " + "%s was not created with %s hash function we are using\n" + "magic1_hash[0x%08X %s 0x%08X] " + "magic2_hash[0x%08X %s 0x%08X]\n", + name, hash_alg, + tdb->header.magic1_hash, + (tdb->header.magic1_hash == magic1) ? "==" : "!=", + magic1, + tdb->header.magic2_hash, + (tdb->header.magic2_hash == magic2) ? "==" : "!=", + magic2)); + errno = EINVAL; + goto fail; + } + + /* Is it already in the open list? If so, fail. */ + if (tdb1_already_open(st.st_dev, st.st_ino)) { + TDB1_LOG((tdb, TDB1_DEBUG_ERROR, "tdb1_open_ex: " + "%s (%d,%d) is already open in this process\n", + name, (int)st.st_dev, (int)st.st_ino)); + errno = EBUSY; + goto fail; + } + + tdb->map_size = st.st_size; + tdb->device = st.st_dev; + tdb->inode = st.st_ino; + tdb1_mmap(tdb); + if (locked) { + if (tdb1_nest_unlock(tdb, TDB1_ACTIVE_LOCK, F_WRLCK, false) == -1) { + TDB1_LOG((tdb, TDB1_DEBUG_ERROR, "tdb1_open_ex: " + "failed to release ACTIVE_LOCK on %s: %s\n", + name, strerror(errno))); + goto fail; + } + + } + + /* We always need to do this if the CLEAR_IF_FIRST flag is set, even if + we didn't get the initial exclusive lock as we need to let all other + users know we're using it. */ + + if (tdb1_flags & TDB1_CLEAR_IF_FIRST) { + /* leave this lock in place to indicate it's in use */ + if (tdb1_nest_lock(tdb, TDB1_ACTIVE_LOCK, F_RDLCK, TDB1_LOCK_WAIT) == -1) { + goto fail; + } + } + + /* if needed, run recovery */ + if (tdb1_transaction_recover(tdb) == -1) { + goto fail; + } + + internal: + /* Internal (memory-only) databases skip all the code above to + * do with disk files, and resume here by releasing their + * open lock and hooking into the active list. */ + if (tdb1_nest_unlock(tdb, TDB1_OPEN_LOCK, F_WRLCK, false) == -1) { + goto fail; + } + tdb->next = tdb1s; + tdb1s = tdb; + return tdb; + + fail: + { int save_errno = errno; + + if (!tdb) + return NULL; + + if (tdb->map_ptr) { + if (tdb->flags & TDB1_INTERNAL) + SAFE_FREE(tdb->map_ptr); + else + tdb1_munmap(tdb); + } + if (tdb->fd != -1) + if (close(tdb->fd) != 0) + TDB1_LOG((tdb, TDB1_DEBUG_ERROR, "tdb1_open_ex: failed to close tdb->fd on error!\n")); + SAFE_FREE(tdb->lockrecs); + SAFE_FREE(tdb->name); + SAFE_FREE(tdb); + errno = save_errno; + return NULL; + } +} + +/* + * Set the maximum number of dead records per hash chain + */ + +_PUBLIC_ void tdb1_set_max_dead(struct tdb1_context *tdb, int max_dead) +{ + tdb->max_dead_records = max_dead; +} + +/** + * Close a database. + * + * @returns -1 for error; 0 for success. + **/ +_PUBLIC_ int tdb1_close(struct tdb1_context *tdb) +{ + struct tdb1_context **i; + int ret = 0; + + if (tdb->transaction) { + tdb1_transaction_cancel(tdb); + } + + if (tdb->map_ptr) { + if (tdb->flags & TDB1_INTERNAL) + SAFE_FREE(tdb->map_ptr); + else + tdb1_munmap(tdb); + } + SAFE_FREE(tdb->name); + if (tdb->fd != -1) { + ret = close(tdb->fd); + tdb->fd = -1; + } + SAFE_FREE(tdb->lockrecs); + + /* Remove from contexts list */ + for (i = &tdb1s; *i; i = &(*i)->next) { + if (*i == tdb) { + *i = tdb->next; + break; + } + } + + memset(tdb, 0, sizeof(*tdb)); + SAFE_FREE(tdb); + + return ret; +} + +/* register a loging function */ +_PUBLIC_ void tdb1_set_logging_function(struct tdb1_context *tdb, + const struct tdb1_logging_context *log_ctx) +{ + tdb->log = *log_ctx; +} + +_PUBLIC_ void *tdb1_get_logging_private(struct tdb1_context *tdb) +{ + return tdb->log.log_private; +} + +static int tdb1_reopen_internal(struct tdb1_context *tdb, bool active_lock) +{ +#if !defined(LIBREPLACE_PREAD_NOT_REPLACED) || \ + !defined(LIBREPLACE_PWRITE_NOT_REPLACED) + struct stat st; +#endif + + if (tdb->flags & TDB1_INTERNAL) { + return 0; /* Nothing to do. */ + } + + if (tdb1_have_extra_locks(tdb)) { + TDB1_LOG((tdb, TDB1_DEBUG_ERROR, "tdb1_reopen: reopen not allowed with locks held\n")); + goto fail; + } + + if (tdb->transaction != 0) { + TDB1_LOG((tdb, TDB1_DEBUG_ERROR, "tdb1_reopen: reopen not allowed inside a transaction\n")); + goto fail; + } + +/* If we have real pread & pwrite, we can skip reopen. */ +#if !defined(LIBREPLACE_PREAD_NOT_REPLACED) || \ + !defined(LIBREPLACE_PWRITE_NOT_REPLACED) + if (tdb1_munmap(tdb) != 0) { + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "tdb1_reopen: munmap failed (%s)\n", strerror(errno))); + goto fail; + } + if (close(tdb->fd) != 0) + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "tdb1_reopen: WARNING closing tdb->fd failed!\n")); + tdb->fd = open(tdb->name, tdb->open_flags & ~(O_CREAT|O_TRUNC), 0); + if (tdb->fd == -1) { + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "tdb1_reopen: open failed (%s)\n", strerror(errno))); + goto fail; + } + if (fstat(tdb->fd, &st) != 0) { + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "tdb1_reopen: fstat failed (%s)\n", strerror(errno))); + goto fail; + } + if (st.st_ino != tdb->inode || st.st_dev != tdb->device) { + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "tdb1_reopen: file dev/inode has changed!\n")); + goto fail; + } + tdb1_mmap(tdb); +#endif /* fake pread or pwrite */ + + /* We may still think we hold the active lock. */ + tdb->num_lockrecs = 0; + SAFE_FREE(tdb->lockrecs); + + if (active_lock && tdb1_nest_lock(tdb, TDB1_ACTIVE_LOCK, F_RDLCK, TDB1_LOCK_WAIT) == -1) { + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "tdb1_reopen: failed to obtain active lock\n")); + goto fail; + } + + return 0; + +fail: + tdb1_close(tdb); + return -1; +} + +/* reopen a tdb - this can be used after a fork to ensure that we have an independent + seek pointer from our parent and to re-establish locks */ +_PUBLIC_ int tdb1_reopen(struct tdb1_context *tdb) +{ + return tdb1_reopen_internal(tdb, tdb->flags & TDB1_CLEAR_IF_FIRST); +} + +/* reopen all tdb's */ +_PUBLIC_ int tdb1_reopen_all(int parent_longlived) +{ + struct tdb1_context *tdb; + + for (tdb=tdb1s; tdb; tdb = tdb->next) { + bool active_lock = (tdb->flags & TDB1_CLEAR_IF_FIRST); + + /* + * If the parent is longlived (ie. a + * parent daemon architecture), we know + * it will keep it's active lock on a + * tdb opened with CLEAR_IF_FIRST. Thus + * for child processes we don't have to + * add an active lock. This is essential + * to improve performance on systems that + * keep POSIX locks as a non-scalable data + * structure in the kernel. + */ + if (parent_longlived) { + /* Ensure no clear-if-first. */ + active_lock = false; + } + + if (tdb1_reopen_internal(tdb, active_lock) != 0) + return -1; + } + + return 0; +} diff --git a/ccan/tdb2/tdb1_private.h b/ccan/tdb2/tdb1_private.h new file mode 100644 index 00000000..569ec718 --- /dev/null +++ b/ccan/tdb2/tdb1_private.h @@ -0,0 +1,294 @@ +#ifndef CCAN_TDB2_TDB1_PRIVATE_H +#define CCAN_TDB2_TDB1_PRIVATE_H + /* + Unix SMB/CIFS implementation. + + trivial database library - private includes + + Copyright (C) Andrew Tridgell 2005 + + ** NOTE! The following LGPL license applies to the tdb + ** library. This does NOT imply that all of Samba is released + ** under the LGPL + + This library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 3 of the License, or (at your option) any later version. + + This library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with this library; if not, see . +*/ + +#ifndef _SAMBA_BUILD_ +#include "config.h" +/* This keeps us consistent with TDB2 code. */ +#if HAVE_FILE_OFFSET_BITS +#define _FILE_OFFSET_BITS 64 +#endif +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#ifndef _PUBLIC_ +#define _PUBLIC_ +#endif + +#else +#include "replace.h" +#include "system/filesys.h" +#include "system/time.h" +#include "system/shmem.h" +#include "system/select.h" +#include "system/wait.h" +#endif + +#include "tdb1.h" + +/* #define TDB_TRACE 1 */ +#ifndef HAVE_GETPAGESIZE +#define getpagesize() 0x2000 +#endif + +#ifndef __STRING +#define __STRING(x) #x +#endif + +#ifndef __STRINGSTRING +#define __STRINGSTRING(x) __STRING(x) +#endif + +#ifndef __location__ +#define __location__ __FILE__ ":" __STRINGSTRING(__LINE__) +#endif + +typedef uint32_t tdb1_len_t; +typedef uint32_t tdb1_off_t; + +#ifndef offsetof +#define offsetof(t,f) ((unsigned int)&((t *)0)->f) +#endif + +#define TDB1_MAGIC_FOOD "TDB file\n" +#define TDB1_VERSION (0x26011967 + 6) +#define TDB1_MAGIC (0x26011999U) +#define TDB1_FREE_MAGIC (~TDB1_MAGIC) +#define TDB1_DEAD_MAGIC (0xFEE1DEAD) +#define TDB1_RECOVERY_MAGIC (0xf53bc0e7U) +#define TDB1_RECOVERY_INVALID_MAGIC (0x0) +#define TDB1_HASH_RWLOCK_MAGIC (0xbad1a51U) +#define TDB1_ALIGNMENT 4 +#define TDB1_DEFAULT_HASH_SIZE 131 +#define TDB1_FREELIST_TOP (sizeof(struct tdb1_header)) +#define TDB1_ALIGN(x,a) (((x) + (a)-1) & ~((a)-1)) +#define TDB1_BYTEREV(x) (((((x)&0xff)<<24)|((x)&0xFF00)<<8)|(((x)>>8)&0xFF00)|((x)>>24)) +#define TDB1_DEAD(r) ((r)->magic == TDB1_DEAD_MAGIC) +#define TDB1_BAD_MAGIC(r) ((r)->magic != TDB1_MAGIC && !TDB1_DEAD(r)) +#define TDB1_HASH_TOP(hash) (TDB1_FREELIST_TOP + (TDB1_BUCKET(hash)+1)*sizeof(tdb1_off_t)) +#define TDB1_HASHTABLE_SIZE(tdb) ((tdb->header.hash_size+1)*sizeof(tdb1_off_t)) +#define TDB1_DATA_START(hash_size) (TDB1_HASH_TOP(hash_size-1) + sizeof(tdb1_off_t)) +#define TDB1_RECOVERY_HEAD offsetof(struct tdb1_header, recovery_start) +#define TDB1_SEQNUM_OFS offsetof(struct tdb1_header, sequence_number) +#define TDB1_PAD_BYTE 0x42 +#define TDB1_PAD_U32 0x42424242 + +/* NB assumes there is a local variable called "tdb" that is the + * current context, also takes doubly-parenthesized print-style + * argument. */ +#define TDB1_LOG(x) tdb->log.log_fn x + +/* lock offsets */ +#define TDB1_OPEN_LOCK 0 +#define TDB1_ACTIVE_LOCK 4 +#define TDB1_TRANSACTION_LOCK 8 + +/* free memory if the pointer is valid and zero the pointer */ +#ifndef SAFE_FREE +#define SAFE_FREE(x) do { if ((x) != NULL) {free(x); (x)=NULL;} } while(0) +#endif + +#define TDB1_BUCKET(hash) ((hash) % tdb->header.hash_size) + +#define TDB1_DOCONV() (tdb->flags & TDB1_CONVERT) +#define TDB1_CONV(x) (TDB1_DOCONV() ? tdb1_convert(&x, sizeof(x)) : &x) + +/* the body of the database is made of one tdb1_record for the free space + plus a separate data list for each hash value */ +struct tdb1_record { + tdb1_off_t next; /* offset of the next record in the list */ + tdb1_len_t rec_len; /* total byte length of record */ + tdb1_len_t key_len; /* byte length of key */ + tdb1_len_t data_len; /* byte length of data */ + uint32_t full_hash; /* the full 32 bit hash of the key */ + uint32_t magic; /* try to catch errors */ + /* the following union is implied: + union { + char record[rec_len]; + struct { + char key[key_len]; + char data[data_len]; + } + uint32_t totalsize; (tailer) + } + */ +}; + + +/* this is stored at the front of every database */ +struct tdb1_header { + char magic_food[32]; /* for /etc/magic */ + uint32_t version; /* version of the code */ + uint32_t hash_size; /* number of hash entries */ + tdb1_off_t rwlocks; /* obsolete - kept to detect old formats */ + tdb1_off_t recovery_start; /* offset of transaction recovery region */ + tdb1_off_t sequence_number; /* used when TDB1_SEQNUM is set */ + uint32_t magic1_hash; /* hash of TDB1_MAGIC_FOOD. */ + uint32_t magic2_hash; /* hash of TDB1_MAGIC. */ + tdb1_off_t reserved[27]; +}; + +struct tdb1_lock_type { + uint32_t off; + uint32_t count; + uint32_t ltype; +}; + +struct tdb1_traverse_lock { + struct tdb1_traverse_lock *next; + uint32_t off; + uint32_t hash; + int lock_rw; +}; + +enum tdb1_lock_flags { + /* WAIT == F_SETLKW, NOWAIT == F_SETLK */ + TDB1_LOCK_NOWAIT = 0, + TDB1_LOCK_WAIT = 1, + /* If set, don't log an error on failure. */ + TDB1_LOCK_PROBE = 2, + /* If set, don't actually lock at all. */ + TDB1_LOCK_MARK_ONLY = 4, +}; + +struct tdb1_context; + +struct tdb1_methods { + int (*tdb1_read)(struct tdb1_context *, tdb1_off_t , void *, tdb1_len_t , int ); + int (*tdb1_write)(struct tdb1_context *, tdb1_off_t, const void *, tdb1_len_t); + void (*next_hash_chain)(struct tdb1_context *, uint32_t *); + int (*tdb1_oob)(struct tdb1_context *, tdb1_off_t , int ); + int (*tdb1_expand_file)(struct tdb1_context *, tdb1_off_t , tdb1_off_t ); +}; + +struct tdb1_context { + char *name; /* the name of the database */ + void *map_ptr; /* where it is currently mapped */ + int fd; /* open file descriptor for the database */ + tdb1_len_t map_size; /* how much space has been mapped */ + int read_only; /* opened read-only */ + int traverse_read; /* read-only traversal */ + int traverse_write; /* read-write traversal */ + struct tdb1_lock_type allrecord_lock; /* .offset == upgradable */ + int num_lockrecs; + struct tdb1_lock_type *lockrecs; /* only real locks, all with count>0 */ + enum TDB1_ERROR ecode; /* error code for last tdb error */ + struct tdb1_header header; /* a cached copy of the header */ + uint32_t flags; /* the flags passed to tdb1_open */ + struct tdb1_traverse_lock travlocks; /* current traversal locks */ + struct tdb1_context *next; /* all tdbs to avoid multiple opens */ + dev_t device; /* uniquely identifies this tdb */ + ino_t inode; /* uniquely identifies this tdb */ + struct tdb1_logging_context log; + unsigned int (*hash_fn)(TDB1_DATA *key); + int open_flags; /* flags used in the open - needed by reopen */ + const struct tdb1_methods *methods; + struct tdb1_transaction *transaction; + int page_size; + int max_dead_records; +#ifdef TDB1_TRACE + int tracefd; +#endif + volatile sig_atomic_t *interrupt_sig_ptr; +}; + + +/* + internal prototypes +*/ +int tdb1_munmap(struct tdb1_context *tdb); +void tdb1_mmap(struct tdb1_context *tdb); +int tdb1_lock(struct tdb1_context *tdb, int list, int ltype); +int tdb1_lock_nonblock(struct tdb1_context *tdb, int list, int ltype); +int tdb1_nest_lock(struct tdb1_context *tdb, uint32_t offset, int ltype, + enum tdb1_lock_flags flags); +int tdb1_nest_unlock(struct tdb1_context *tdb, uint32_t offset, int ltype, + bool mark_lock); +int tdb1_unlock(struct tdb1_context *tdb, int list, int ltype); +int tdb1_brlock(struct tdb1_context *tdb, + int rw_type, tdb1_off_t offset, size_t len, + enum tdb1_lock_flags flags); +int tdb1_brunlock(struct tdb1_context *tdb, + int rw_type, tdb1_off_t offset, size_t len); +bool tdb1_have_extra_locks(struct tdb1_context *tdb); +void tdb1_release_transaction_locks(struct tdb1_context *tdb); +int tdb1_transaction_lock(struct tdb1_context *tdb, int ltype, + enum tdb1_lock_flags lockflags); +int tdb1_transaction_unlock(struct tdb1_context *tdb, int ltype); +int tdb1_recovery_area(struct tdb1_context *tdb, + const struct tdb1_methods *methods, + tdb1_off_t *recovery_offset, + struct tdb1_record *rec); +int tdb1_allrecord_lock(struct tdb1_context *tdb, int ltype, + enum tdb1_lock_flags flags, bool upgradable); +int tdb1_allrecord_unlock(struct tdb1_context *tdb, int ltype, bool mark_lock); +int tdb1_allrecord_upgrade(struct tdb1_context *tdb); +int tdb1_write_lock_record(struct tdb1_context *tdb, tdb1_off_t off); +int tdb1_write_unlock_record(struct tdb1_context *tdb, tdb1_off_t off); +int tdb1_ofs_read(struct tdb1_context *tdb, tdb1_off_t offset, tdb1_off_t *d); +int tdb1_ofs_write(struct tdb1_context *tdb, tdb1_off_t offset, tdb1_off_t *d); +void *tdb1_convert(void *buf, uint32_t size); +int tdb1_free(struct tdb1_context *tdb, tdb1_off_t offset, struct tdb1_record *rec); +tdb1_off_t tdb1_allocate(struct tdb1_context *tdb, tdb1_len_t length, struct tdb1_record *rec); +int tdb1_ofs_read(struct tdb1_context *tdb, tdb1_off_t offset, tdb1_off_t *d); +int tdb1_ofs_write(struct tdb1_context *tdb, tdb1_off_t offset, tdb1_off_t *d); +int tdb1_lock_record(struct tdb1_context *tdb, tdb1_off_t off); +int tdb1_unlock_record(struct tdb1_context *tdb, tdb1_off_t off); +bool tdb1_needs_recovery(struct tdb1_context *tdb); +int tdb1_rec_read(struct tdb1_context *tdb, tdb1_off_t offset, struct tdb1_record *rec); +int tdb1_rec_write(struct tdb1_context *tdb, tdb1_off_t offset, struct tdb1_record *rec); +int tdb1_do_delete(struct tdb1_context *tdb, tdb1_off_t rec_ptr, struct tdb1_record *rec); +unsigned char *tdb1_alloc_read(struct tdb1_context *tdb, tdb1_off_t offset, tdb1_len_t len); +int tdb1_parse_data(struct tdb1_context *tdb, TDB1_DATA key, + tdb1_off_t offset, tdb1_len_t len, + int (*parser)(TDB1_DATA key, TDB1_DATA data, + void *private_data), + void *private_data); +tdb1_off_t tdb1_find_lock_hash(struct tdb1_context *tdb, TDB1_DATA key, uint32_t hash, int locktype, + struct tdb1_record *rec); +void tdb1_io_init(struct tdb1_context *tdb); +int tdb1_expand(struct tdb1_context *tdb, tdb1_off_t size); +int tdb1_rec_free_read(struct tdb1_context *tdb, tdb1_off_t off, + struct tdb1_record *rec); +bool tdb1_write_all(int fd, const void *buf, size_t count); +int tdb1_transaction_recover(struct tdb1_context *tdb); +void tdb1_header_hash(struct tdb1_context *tdb, + uint32_t *magic1_hash, uint32_t *magic2_hash); +unsigned int tdb1_old_hash(TDB1_DATA *key); +size_t tdb1_dead_space(struct tdb1_context *tdb, tdb1_off_t off); +#endif /* CCAN_TDB2_TDB1_PRIVATE_H */ diff --git a/ccan/tdb2/tdb1_summary.c b/ccan/tdb2/tdb1_summary.c new file mode 100644 index 00000000..61e18535 --- /dev/null +++ b/ccan/tdb2/tdb1_summary.c @@ -0,0 +1,201 @@ + /* + Trivial Database: human-readable summary code + Copyright (C) Rusty Russell 2010 + + This library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 3 of the License, or (at your option) any later version. + + This library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with this library; if not, see . +*/ +#include "tdb1_private.h" + +#define SUMMARY_FORMAT1 \ + "Size of file/data: %u/%zu\n" \ + "Number of records: %zu\n" \ + "Smallest/average/largest keys: %zu/%zu/%zu\n" \ + "Smallest/average/largest data: %zu/%zu/%zu\n" \ + "Smallest/average/largest padding: %zu/%zu/%zu\n" \ + "Number of dead records: %zu\n" \ + "Smallest/average/largest dead records: %zu/%zu/%zu\n" \ + "Number of free records: %zu\n" \ + "Smallest/average/largest free records: %zu/%zu/%zu\n" \ + "Number of hash chains: %zu\n" \ + "Smallest/average/largest hash chains: %zu/%zu/%zu\n" \ + "Number of uncoalesced records: %zu\n" \ + "Smallest/average/largest uncoalesced runs: %zu/%zu/%zu\n" \ + "Percentage keys/data/padding/free/dead/rechdrs&tailers/hashes: %.0f/%.0f/%.0f/%.0f/%.0f/%.0f/%.0f\n" + +/* We don't use tally module, to keep upstream happy. */ +struct tally { + size_t min, max, total; + size_t num; +}; + +static void tally1_init(struct tally *tally) +{ + tally->total = 0; + tally->num = 0; + tally->min = tally->max = 0; +} + +static void tally1_add(struct tally *tally, size_t len) +{ + if (tally->num == 0) + tally->max = tally->min = len; + else if (len > tally->max) + tally->max = len; + else if (len < tally->min) + tally->min = len; + tally->num++; + tally->total += len; +} + +static size_t tally1_mean(const struct tally *tally) +{ + if (!tally->num) + return 0; + return tally->total / tally->num; +} + +static size_t get_hash_length(struct tdb1_context *tdb, unsigned int i) +{ + tdb1_off_t rec_ptr; + size_t count = 0; + + if (tdb1_ofs_read(tdb, TDB1_HASH_TOP(i), &rec_ptr) == -1) + return 0; + + /* keep looking until we find the right record */ + while (rec_ptr) { + struct tdb1_record r; + ++count; + if (tdb1_rec_read(tdb, rec_ptr, &r) == -1) + return 0; + rec_ptr = r.next; + } + return count; +} + +_PUBLIC_ char *tdb1_summary(struct tdb1_context *tdb) +{ + tdb1_off_t off, rec_off; + struct tally freet, keys, data, dead, extra, hash, uncoal; + struct tdb1_record rec; + char *ret = NULL; + bool locked; + size_t len, unc = 0; + struct tdb1_record recovery; + + /* Read-only databases use no locking at all: it's best-effort. + * We may have a write lock already, so skip that case too. */ + if (tdb->read_only || tdb->allrecord_lock.count != 0) { + locked = false; + } else { + if (tdb1_lockall_read(tdb) == -1) + return NULL; + locked = true; + } + + if (tdb1_recovery_area(tdb, tdb->methods, &rec_off, &recovery) != 0) { + goto unlock; + } + + tally1_init(&freet); + tally1_init(&keys); + tally1_init(&data); + tally1_init(&dead); + tally1_init(&extra); + tally1_init(&hash); + tally1_init(&uncoal); + + for (off = TDB1_DATA_START(tdb->header.hash_size); + off < tdb->map_size - 1; + off += sizeof(rec) + rec.rec_len) { + if (tdb->methods->tdb1_read(tdb, off, &rec, sizeof(rec), + TDB1_DOCONV()) == -1) + goto unlock; + switch (rec.magic) { + case TDB1_MAGIC: + tally1_add(&keys, rec.key_len); + tally1_add(&data, rec.data_len); + tally1_add(&extra, rec.rec_len - (rec.key_len + + rec.data_len)); + if (unc > 1) + tally1_add(&uncoal, unc - 1); + unc = 0; + break; + case TDB1_FREE_MAGIC: + tally1_add(&freet, rec.rec_len); + unc++; + break; + /* If we crash after ftruncate, we can get zeroes or fill. */ + case TDB1_RECOVERY_INVALID_MAGIC: + case 0x42424242: + unc++; + /* If it's a valid recovery, we can trust rec_len. */ + if (off != rec_off) { + rec.rec_len = tdb1_dead_space(tdb, off) + - sizeof(rec); + } + /* Fall through */ + case TDB1_DEAD_MAGIC: + tally1_add(&dead, rec.rec_len); + break; + default: + TDB1_LOG((tdb, TDB1_DEBUG_ERROR, + "Unexpected record magic 0x%x at offset %d\n", + rec.magic, off)); + goto unlock; + } + } + if (unc > 1) + tally1_add(&uncoal, unc - 1); + + for (off = 0; off < tdb->header.hash_size; off++) + tally1_add(&hash, get_hash_length(tdb, off)); + + /* 20 is max length of a %zu. */ + len = strlen(SUMMARY_FORMAT1) + 35*20 + 1; + ret = (char *)malloc(len); + if (!ret) + goto unlock; + + snprintf(ret, len, SUMMARY_FORMAT1, + tdb->map_size, keys.total+data.total, + keys.num, + keys.min, tally1_mean(&keys), keys.max, + data.min, tally1_mean(&data), data.max, + extra.min, tally1_mean(&extra), extra.max, + dead.num, + dead.min, tally1_mean(&dead), dead.max, + freet.num, + freet.min, tally1_mean(&freet), freet.max, + hash.num, + hash.min, tally1_mean(&hash), hash.max, + uncoal.total, + uncoal.min, tally1_mean(&uncoal), uncoal.max, + keys.total * 100.0 / tdb->map_size, + data.total * 100.0 / tdb->map_size, + extra.total * 100.0 / tdb->map_size, + freet.total * 100.0 / tdb->map_size, + dead.total * 100.0 / tdb->map_size, + (keys.num + freet.num + dead.num) + * (sizeof(struct tdb1_record) + sizeof(uint32_t)) + * 100.0 / tdb->map_size, + tdb->header.hash_size * sizeof(tdb1_off_t) + * 100.0 / tdb->map_size); + +unlock: + if (locked) { + tdb1_unlockall_read(tdb); + } + return ret; +} diff --git a/ccan/tdb2/tdb1_tdb.c b/ccan/tdb2/tdb1_tdb.c new file mode 100644 index 00000000..1ada443d --- /dev/null +++ b/ccan/tdb2/tdb1_tdb.c @@ -0,0 +1,993 @@ + /* + Unix SMB/CIFS implementation. + + trivial database library + + Copyright (C) Andrew Tridgell 1999-2005 + Copyright (C) Paul `Rusty' Russell 2000 + Copyright (C) Jeremy Allison 2000-2003 + + ** NOTE! The following LGPL license applies to the tdb + ** library. This does NOT imply that all of Samba is released + ** under the LGPL + + This library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 3 of the License, or (at your option) any later version. + + This library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with this library; if not, see . +*/ + +#include "tdb1_private.h" + +_PUBLIC_ TDB1_DATA tdb1_null; + +/* + non-blocking increment of the tdb sequence number if the tdb has been opened using + the TDB1_SEQNUM flag +*/ +_PUBLIC_ void tdb1_increment_seqnum_nonblock(struct tdb1_context *tdb) +{ + tdb1_off_t seqnum=0; + + if (!(tdb->flags & TDB1_SEQNUM)) { + return; + } + + /* we ignore errors from this, as we have no sane way of + dealing with them. + */ + tdb1_ofs_read(tdb, TDB1_SEQNUM_OFS, &seqnum); + seqnum++; + tdb1_ofs_write(tdb, TDB1_SEQNUM_OFS, &seqnum); +} + +/* + increment the tdb sequence number if the tdb has been opened using + the TDB1_SEQNUM flag +*/ +static void tdb1_increment_seqnum(struct tdb1_context *tdb) +{ + if (!(tdb->flags & TDB1_SEQNUM)) { + return; + } + + if (tdb1_nest_lock(tdb, TDB1_SEQNUM_OFS, F_WRLCK, + TDB1_LOCK_WAIT|TDB1_LOCK_PROBE) != 0) { + return; + } + + tdb1_increment_seqnum_nonblock(tdb); + + tdb1_nest_unlock(tdb, TDB1_SEQNUM_OFS, F_WRLCK, false); +} + +static int tdb1_key_compare(TDB1_DATA key, TDB1_DATA data, void *private_data) +{ + return memcmp(data.dptr, key.dptr, data.dsize); +} + +/* Returns 0 on fail. On success, return offset of record, and fills + in rec */ +static tdb1_off_t tdb1_find(struct tdb1_context *tdb, TDB1_DATA key, uint32_t hash, + struct tdb1_record *r) +{ + tdb1_off_t rec_ptr; + + /* read in the hash top */ + if (tdb1_ofs_read(tdb, TDB1_HASH_TOP(hash), &rec_ptr) == -1) + return 0; + + /* keep looking until we find the right record */ + while (rec_ptr) { + if (tdb1_rec_read(tdb, rec_ptr, r) == -1) + return 0; + + if (!TDB1_DEAD(r) && hash==r->full_hash + && key.dsize==r->key_len + && tdb1_parse_data(tdb, key, rec_ptr + sizeof(*r), + r->key_len, tdb1_key_compare, + NULL) == 0) { + return rec_ptr; + } + /* detect tight infinite loop */ + if (rec_ptr == r->next) { + tdb->ecode = TDB1_ERR_CORRUPT; + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "tdb1_find: loop detected.\n")); + return 0; + } + rec_ptr = r->next; + } + tdb->ecode = TDB1_ERR_NOEXIST; + return 0; +} + +/* As tdb1_find, but if you succeed, keep the lock */ +tdb1_off_t tdb1_find_lock_hash(struct tdb1_context *tdb, TDB1_DATA key, uint32_t hash, int locktype, + struct tdb1_record *rec) +{ + uint32_t rec_ptr; + + if (tdb1_lock(tdb, TDB1_BUCKET(hash), locktype) == -1) + return 0; + if (!(rec_ptr = tdb1_find(tdb, key, hash, rec))) + tdb1_unlock(tdb, TDB1_BUCKET(hash), locktype); + return rec_ptr; +} + +static TDB1_DATA _tdb1_fetch(struct tdb1_context *tdb, TDB1_DATA key); + +/* update an entry in place - this only works if the new data size + is <= the old data size and the key exists. + on failure return -1. +*/ +static int tdb1_update_hash(struct tdb1_context *tdb, TDB1_DATA key, uint32_t hash, TDB1_DATA dbuf) +{ + struct tdb1_record rec; + tdb1_off_t rec_ptr; + + /* find entry */ + if (!(rec_ptr = tdb1_find(tdb, key, hash, &rec))) + return -1; + + /* it could be an exact duplicate of what is there - this is + * surprisingly common (eg. with a ldb re-index). */ + if (rec.key_len == key.dsize && + rec.data_len == dbuf.dsize && + rec.full_hash == hash) { + TDB1_DATA data = _tdb1_fetch(tdb, key); + if (data.dsize == dbuf.dsize && + memcmp(data.dptr, dbuf.dptr, data.dsize) == 0) { + if (data.dptr) { + free(data.dptr); + } + return 0; + } + if (data.dptr) { + free(data.dptr); + } + } + + /* must be long enough key, data and tailer */ + if (rec.rec_len < key.dsize + dbuf.dsize + sizeof(tdb1_off_t)) { + tdb->ecode = TDB1_SUCCESS; /* Not really an error */ + return -1; + } + + if (tdb->methods->tdb1_write(tdb, rec_ptr + sizeof(rec) + rec.key_len, + dbuf.dptr, dbuf.dsize) == -1) + return -1; + + if (dbuf.dsize != rec.data_len) { + /* update size */ + rec.data_len = dbuf.dsize; + return tdb1_rec_write(tdb, rec_ptr, &rec); + } + + return 0; +} + +/* find an entry in the database given a key */ +/* If an entry doesn't exist tdb1_err will be set to + * TDB1_ERR_NOEXIST. If a key has no data attached + * then the TDB1_DATA will have zero length but + * a non-zero pointer + */ +static TDB1_DATA _tdb1_fetch(struct tdb1_context *tdb, TDB1_DATA key) +{ + tdb1_off_t rec_ptr; + struct tdb1_record rec; + TDB1_DATA ret; + uint32_t hash; + + /* find which hash bucket it is in */ + hash = tdb->hash_fn(&key); + if (!(rec_ptr = tdb1_find_lock_hash(tdb,key,hash,F_RDLCK,&rec))) + return tdb1_null; + + ret.dptr = tdb1_alloc_read(tdb, rec_ptr + sizeof(rec) + rec.key_len, + rec.data_len); + ret.dsize = rec.data_len; + tdb1_unlock(tdb, TDB1_BUCKET(rec.full_hash), F_RDLCK); + return ret; +} + +_PUBLIC_ TDB1_DATA tdb1_fetch(struct tdb1_context *tdb, TDB1_DATA key) +{ + TDB1_DATA ret = _tdb1_fetch(tdb, key); + + return ret; +} + +/* + * Find an entry in the database and hand the record's data to a parsing + * function. The parsing function is executed under the chain read lock, so it + * should be fast and should not block on other syscalls. + * + * DON'T CALL OTHER TDB CALLS FROM THE PARSER, THIS MIGHT LEAD TO SEGFAULTS. + * + * For mmapped tdb's that do not have a transaction open it points the parsing + * function directly at the mmap area, it avoids the malloc/memcpy in this + * case. If a transaction is open or no mmap is available, it has to do + * malloc/read/parse/free. + * + * This is interesting for all readers of potentially large data structures in + * the tdb records, ldb indexes being one example. + * + * Return -1 if the record was not found. + */ + +_PUBLIC_ int tdb1_parse_record(struct tdb1_context *tdb, TDB1_DATA key, + int (*parser)(TDB1_DATA key, TDB1_DATA data, + void *private_data), + void *private_data) +{ + tdb1_off_t rec_ptr; + struct tdb1_record rec; + int ret; + uint32_t hash; + + /* find which hash bucket it is in */ + hash = tdb->hash_fn(&key); + + if (!(rec_ptr = tdb1_find_lock_hash(tdb,key,hash,F_RDLCK,&rec))) { + /* record not found */ + tdb->ecode = TDB1_ERR_NOEXIST; + return -1; + } + + ret = tdb1_parse_data(tdb, key, rec_ptr + sizeof(rec) + rec.key_len, + rec.data_len, parser, private_data); + + tdb1_unlock(tdb, TDB1_BUCKET(rec.full_hash), F_RDLCK); + + return ret; +} + +/* check if an entry in the database exists + + note that 1 is returned if the key is found and 0 is returned if not found + this doesn't match the conventions in the rest of this module, but is + compatible with gdbm +*/ +static int tdb1_exists_hash(struct tdb1_context *tdb, TDB1_DATA key, uint32_t hash) +{ + struct tdb1_record rec; + + if (tdb1_find_lock_hash(tdb, key, hash, F_RDLCK, &rec) == 0) + return 0; + tdb1_unlock(tdb, TDB1_BUCKET(rec.full_hash), F_RDLCK); + return 1; +} + +_PUBLIC_ int tdb1_exists(struct tdb1_context *tdb, TDB1_DATA key) +{ + uint32_t hash = tdb->hash_fn(&key); + int ret; + + ret = tdb1_exists_hash(tdb, key, hash); + return ret; +} + +/* actually delete an entry in the database given the offset */ +int tdb1_do_delete(struct tdb1_context *tdb, tdb1_off_t rec_ptr, struct tdb1_record *rec) +{ + tdb1_off_t last_ptr, i; + struct tdb1_record lastrec; + + if (tdb->read_only || tdb->traverse_read) return -1; + + if (((tdb->traverse_write != 0) && (!TDB1_DEAD(rec))) || + tdb1_write_lock_record(tdb, rec_ptr) == -1) { + /* Someone traversing here: mark it as dead */ + rec->magic = TDB1_DEAD_MAGIC; + return tdb1_rec_write(tdb, rec_ptr, rec); + } + if (tdb1_write_unlock_record(tdb, rec_ptr) != 0) + return -1; + + /* find previous record in hash chain */ + if (tdb1_ofs_read(tdb, TDB1_HASH_TOP(rec->full_hash), &i) == -1) + return -1; + for (last_ptr = 0; i != rec_ptr; last_ptr = i, i = lastrec.next) + if (tdb1_rec_read(tdb, i, &lastrec) == -1) + return -1; + + /* unlink it: next ptr is at start of record. */ + if (last_ptr == 0) + last_ptr = TDB1_HASH_TOP(rec->full_hash); + if (tdb1_ofs_write(tdb, last_ptr, &rec->next) == -1) + return -1; + + /* recover the space */ + if (tdb1_free(tdb, rec_ptr, rec) == -1) + return -1; + return 0; +} + +static int tdb1_count_dead(struct tdb1_context *tdb, uint32_t hash) +{ + int res = 0; + tdb1_off_t rec_ptr; + struct tdb1_record rec; + + /* read in the hash top */ + if (tdb1_ofs_read(tdb, TDB1_HASH_TOP(hash), &rec_ptr) == -1) + return 0; + + while (rec_ptr) { + if (tdb1_rec_read(tdb, rec_ptr, &rec) == -1) + return 0; + + if (rec.magic == TDB1_DEAD_MAGIC) { + res += 1; + } + rec_ptr = rec.next; + } + return res; +} + +/* + * Purge all DEAD records from a hash chain + */ +static int tdb1_purge_dead(struct tdb1_context *tdb, uint32_t hash) +{ + int res = -1; + struct tdb1_record rec; + tdb1_off_t rec_ptr; + + if (tdb1_lock(tdb, -1, F_WRLCK) == -1) { + return -1; + } + + /* read in the hash top */ + if (tdb1_ofs_read(tdb, TDB1_HASH_TOP(hash), &rec_ptr) == -1) + goto fail; + + while (rec_ptr) { + tdb1_off_t next; + + if (tdb1_rec_read(tdb, rec_ptr, &rec) == -1) { + goto fail; + } + + next = rec.next; + + if (rec.magic == TDB1_DEAD_MAGIC + && tdb1_do_delete(tdb, rec_ptr, &rec) == -1) { + goto fail; + } + rec_ptr = next; + } + res = 0; + fail: + tdb1_unlock(tdb, -1, F_WRLCK); + return res; +} + +/* delete an entry in the database given a key */ +static int tdb1_delete_hash(struct tdb1_context *tdb, TDB1_DATA key, uint32_t hash) +{ + tdb1_off_t rec_ptr; + struct tdb1_record rec; + int ret; + + if (tdb->max_dead_records != 0) { + + /* + * Allow for some dead records per hash chain, mainly for + * tdb's with a very high create/delete rate like locking.tdb. + */ + + if (tdb1_lock(tdb, TDB1_BUCKET(hash), F_WRLCK) == -1) + return -1; + + if (tdb1_count_dead(tdb, hash) >= tdb->max_dead_records) { + /* + * Don't let the per-chain freelist grow too large, + * delete all existing dead records + */ + tdb1_purge_dead(tdb, hash); + } + + if (!(rec_ptr = tdb1_find(tdb, key, hash, &rec))) { + tdb1_unlock(tdb, TDB1_BUCKET(hash), F_WRLCK); + return -1; + } + + /* + * Just mark the record as dead. + */ + rec.magic = TDB1_DEAD_MAGIC; + ret = tdb1_rec_write(tdb, rec_ptr, &rec); + } + else { + if (!(rec_ptr = tdb1_find_lock_hash(tdb, key, hash, F_WRLCK, + &rec))) + return -1; + + ret = tdb1_do_delete(tdb, rec_ptr, &rec); + } + + if (ret == 0) { + tdb1_increment_seqnum(tdb); + } + + if (tdb1_unlock(tdb, TDB1_BUCKET(rec.full_hash), F_WRLCK) != 0) + TDB1_LOG((tdb, TDB1_DEBUG_WARNING, "tdb1_delete: WARNING tdb1_unlock failed!\n")); + return ret; +} + +_PUBLIC_ int tdb1_delete(struct tdb1_context *tdb, TDB1_DATA key) +{ + uint32_t hash = tdb->hash_fn(&key); + int ret; + + ret = tdb1_delete_hash(tdb, key, hash); + return ret; +} + +/* + * See if we have a dead record around with enough space + */ +static tdb1_off_t tdb1_find_dead(struct tdb1_context *tdb, uint32_t hash, + struct tdb1_record *r, tdb1_len_t length) +{ + tdb1_off_t rec_ptr; + + /* read in the hash top */ + if (tdb1_ofs_read(tdb, TDB1_HASH_TOP(hash), &rec_ptr) == -1) + return 0; + + /* keep looking until we find the right record */ + while (rec_ptr) { + if (tdb1_rec_read(tdb, rec_ptr, r) == -1) + return 0; + + if (TDB1_DEAD(r) && r->rec_len >= length) { + /* + * First fit for simple coding, TODO: change to best + * fit + */ + return rec_ptr; + } + rec_ptr = r->next; + } + return 0; +} + +static int _tdb1_store(struct tdb1_context *tdb, TDB1_DATA key, + TDB1_DATA dbuf, int flag, uint32_t hash) +{ + struct tdb1_record rec; + tdb1_off_t rec_ptr; + char *p = NULL; + int ret = -1; + + /* check for it existing, on insert. */ + if (flag == TDB1_INSERT) { + if (tdb1_exists_hash(tdb, key, hash)) { + tdb->ecode = TDB1_ERR_EXISTS; + goto fail; + } + } else { + /* first try in-place update, on modify or replace. */ + if (tdb1_update_hash(tdb, key, hash, dbuf) == 0) { + goto done; + } + if (tdb->ecode == TDB1_ERR_NOEXIST && + flag == TDB1_MODIFY) { + /* if the record doesn't exist and we are in TDB1_MODIFY mode then + we should fail the store */ + goto fail; + } + } + /* reset the error code potentially set by the tdb1_update() */ + tdb->ecode = TDB1_SUCCESS; + + /* delete any existing record - if it doesn't exist we don't + care. Doing this first reduces fragmentation, and avoids + coalescing with `allocated' block before it's updated. */ + if (flag != TDB1_INSERT) + tdb1_delete_hash(tdb, key, hash); + + /* Copy key+value *before* allocating free space in case malloc + fails and we are left with a dead spot in the tdb. */ + + if (!(p = (char *)malloc(key.dsize + dbuf.dsize))) { + tdb->ecode = TDB1_ERR_OOM; + goto fail; + } + + memcpy(p, key.dptr, key.dsize); + if (dbuf.dsize) + memcpy(p+key.dsize, dbuf.dptr, dbuf.dsize); + + if (tdb->max_dead_records != 0) { + /* + * Allow for some dead records per hash chain, look if we can + * find one that can hold the new record. We need enough space + * for key, data and tailer. If we find one, we don't have to + * consult the central freelist. + */ + rec_ptr = tdb1_find_dead( + tdb, hash, &rec, + key.dsize + dbuf.dsize + sizeof(tdb1_off_t)); + + if (rec_ptr != 0) { + rec.key_len = key.dsize; + rec.data_len = dbuf.dsize; + rec.full_hash = hash; + rec.magic = TDB1_MAGIC; + if (tdb1_rec_write(tdb, rec_ptr, &rec) == -1 + || tdb->methods->tdb1_write( + tdb, rec_ptr + sizeof(rec), + p, key.dsize + dbuf.dsize) == -1) { + goto fail; + } + goto done; + } + } + + /* + * We have to allocate some space from the freelist, so this means we + * have to lock it. Use the chance to purge all the DEAD records from + * the hash chain under the freelist lock. + */ + + if (tdb1_lock(tdb, -1, F_WRLCK) == -1) { + goto fail; + } + + if ((tdb->max_dead_records != 0) + && (tdb1_purge_dead(tdb, hash) == -1)) { + tdb1_unlock(tdb, -1, F_WRLCK); + goto fail; + } + + /* we have to allocate some space */ + rec_ptr = tdb1_allocate(tdb, key.dsize + dbuf.dsize, &rec); + + tdb1_unlock(tdb, -1, F_WRLCK); + + if (rec_ptr == 0) { + goto fail; + } + + /* Read hash top into next ptr */ + if (tdb1_ofs_read(tdb, TDB1_HASH_TOP(hash), &rec.next) == -1) + goto fail; + + rec.key_len = key.dsize; + rec.data_len = dbuf.dsize; + rec.full_hash = hash; + rec.magic = TDB1_MAGIC; + + /* write out and point the top of the hash chain at it */ + if (tdb1_rec_write(tdb, rec_ptr, &rec) == -1 + || tdb->methods->tdb1_write(tdb, rec_ptr+sizeof(rec), p, key.dsize+dbuf.dsize)==-1 + || tdb1_ofs_write(tdb, TDB1_HASH_TOP(hash), &rec_ptr) == -1) { + /* Need to tdb1_unallocate() here */ + goto fail; + } + + done: + ret = 0; + fail: + if (ret == 0) { + tdb1_increment_seqnum(tdb); + } + + SAFE_FREE(p); + return ret; +} + +/* store an element in the database, replacing any existing element + with the same key + + return 0 on success, -1 on failure +*/ +_PUBLIC_ int tdb1_store(struct tdb1_context *tdb, TDB1_DATA key, TDB1_DATA dbuf, int flag) +{ + uint32_t hash; + int ret; + + if (tdb->read_only || tdb->traverse_read) { + tdb->ecode = TDB1_ERR_RDONLY; + return -1; + } + + /* find which hash bucket it is in */ + hash = tdb->hash_fn(&key); + if (tdb1_lock(tdb, TDB1_BUCKET(hash), F_WRLCK) == -1) + return -1; + + ret = _tdb1_store(tdb, key, dbuf, flag, hash); + tdb1_unlock(tdb, TDB1_BUCKET(hash), F_WRLCK); + return ret; +} + +/* Append to an entry. Create if not exist. */ +_PUBLIC_ int tdb1_append(struct tdb1_context *tdb, TDB1_DATA key, TDB1_DATA new_dbuf) +{ + uint32_t hash; + TDB1_DATA dbuf; + int ret = -1; + + /* find which hash bucket it is in */ + hash = tdb->hash_fn(&key); + if (tdb1_lock(tdb, TDB1_BUCKET(hash), F_WRLCK) == -1) + return -1; + + dbuf = _tdb1_fetch(tdb, key); + + if (dbuf.dptr == NULL) { + dbuf.dptr = (unsigned char *)malloc(new_dbuf.dsize); + } else { + unsigned int new_len = dbuf.dsize + new_dbuf.dsize; + unsigned char *new_dptr; + + /* realloc '0' is special: don't do that. */ + if (new_len == 0) + new_len = 1; + new_dptr = (unsigned char *)realloc(dbuf.dptr, new_len); + if (new_dptr == NULL) { + free(dbuf.dptr); + } + dbuf.dptr = new_dptr; + } + + if (dbuf.dptr == NULL) { + tdb->ecode = TDB1_ERR_OOM; + goto failed; + } + + memcpy(dbuf.dptr + dbuf.dsize, new_dbuf.dptr, new_dbuf.dsize); + dbuf.dsize += new_dbuf.dsize; + + ret = _tdb1_store(tdb, key, dbuf, 0, hash); + +failed: + tdb1_unlock(tdb, TDB1_BUCKET(hash), F_WRLCK); + SAFE_FREE(dbuf.dptr); + return ret; +} + + +/* + return the name of the current tdb file + useful for external logging functions +*/ +_PUBLIC_ const char *tdb1_name(struct tdb1_context *tdb) +{ + return tdb->name; +} + +/* + return the underlying file descriptor being used by tdb, or -1 + useful for external routines that want to check the device/inode + of the fd +*/ +_PUBLIC_ int tdb1_fd(struct tdb1_context *tdb) +{ + return tdb->fd; +} + +/* + return the current logging function + useful for external tdb routines that wish to log tdb errors +*/ +_PUBLIC_ tdb1_log_func tdb1_log_fn(struct tdb1_context *tdb) +{ + return tdb->log.log_fn; +} + + +/* + get the tdb sequence number. Only makes sense if the writers opened + with TDB1_SEQNUM set. Note that this sequence number will wrap quite + quickly, so it should only be used for a 'has something changed' + test, not for code that relies on the count of the number of changes + made. If you want a counter then use a tdb record. + + The aim of this sequence number is to allow for a very lightweight + test of a possible tdb change. +*/ +_PUBLIC_ int tdb1_get_seqnum(struct tdb1_context *tdb) +{ + tdb1_off_t seqnum=0; + + tdb1_ofs_read(tdb, TDB1_SEQNUM_OFS, &seqnum); + return seqnum; +} + +_PUBLIC_ int tdb1_hash_size(struct tdb1_context *tdb) +{ + return tdb->header.hash_size; +} + +_PUBLIC_ size_t tdb1_map_size(struct tdb1_context *tdb) +{ + return tdb->map_size; +} + +_PUBLIC_ int tdb1_get_flags(struct tdb1_context *tdb) +{ + return tdb->flags; +} + +_PUBLIC_ void tdb1_add_flags(struct tdb1_context *tdb, unsigned flags) +{ + if ((flags & TDB1_ALLOW_NESTING) && + (flags & TDB1_DISALLOW_NESTING)) { + tdb->ecode = TDB1_ERR_NESTING; + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "tdb1_add_flags: " + "allow_nesting and disallow_nesting are not allowed together!")); + return; + } + + if (flags & TDB1_ALLOW_NESTING) { + tdb->flags &= ~TDB1_DISALLOW_NESTING; + } + if (flags & TDB1_DISALLOW_NESTING) { + tdb->flags &= ~TDB1_ALLOW_NESTING; + } + + tdb->flags |= flags; +} + +_PUBLIC_ void tdb1_remove_flags(struct tdb1_context *tdb, unsigned flags) +{ + if ((flags & TDB1_ALLOW_NESTING) && + (flags & TDB1_DISALLOW_NESTING)) { + tdb->ecode = TDB1_ERR_NESTING; + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "tdb1_remove_flags: " + "allow_nesting and disallow_nesting are not allowed together!")); + return; + } + + if (flags & TDB1_ALLOW_NESTING) { + tdb->flags |= TDB1_DISALLOW_NESTING; + } + if (flags & TDB1_DISALLOW_NESTING) { + tdb->flags |= TDB1_ALLOW_NESTING; + } + + tdb->flags &= ~flags; +} + + +/* + enable sequence number handling on an open tdb +*/ +_PUBLIC_ void tdb1_enable_seqnum(struct tdb1_context *tdb) +{ + tdb->flags |= TDB1_SEQNUM; +} + + +/* + add a region of the file to the freelist. Length is the size of the region in bytes, + which includes the free list header that needs to be added + */ +static int tdb1_free_region(struct tdb1_context *tdb, tdb1_off_t offset, ssize_t length) +{ + struct tdb1_record rec; + if (length <= sizeof(rec)) { + /* the region is not worth adding */ + return 0; + } + if (length + offset > tdb->map_size) { + TDB1_LOG((tdb, TDB1_DEBUG_FATAL,"tdb1_free_region: adding region beyond end of file\n")); + return -1; + } + memset(&rec,'\0',sizeof(rec)); + rec.rec_len = length - sizeof(rec); + if (tdb1_free(tdb, offset, &rec) == -1) { + TDB1_LOG((tdb, TDB1_DEBUG_FATAL,"tdb1_free_region: failed to add free record\n")); + return -1; + } + return 0; +} + +/* + wipe the entire database, deleting all records. This can be done + very fast by using a allrecord lock. The entire data portion of the + file becomes a single entry in the freelist. + + This code carefully steps around the recovery area, leaving it alone + */ +_PUBLIC_ int tdb1_wipe_all(struct tdb1_context *tdb) +{ + int i; + tdb1_off_t offset = 0; + ssize_t data_len; + tdb1_off_t recovery_head; + tdb1_len_t recovery_size = 0; + + if (tdb1_lockall(tdb) != 0) { + return -1; + } + + + /* see if the tdb has a recovery area, and remember its size + if so. We don't want to lose this as otherwise each + tdb1_wipe_all() in a transaction will increase the size of + the tdb by the size of the recovery area */ + if (tdb1_ofs_read(tdb, TDB1_RECOVERY_HEAD, &recovery_head) == -1) { + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "tdb1_wipe_all: failed to read recovery head\n")); + goto failed; + } + + if (recovery_head != 0) { + struct tdb1_record rec; + if (tdb->methods->tdb1_read(tdb, recovery_head, &rec, sizeof(rec), TDB1_DOCONV()) == -1) { + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "tdb1_wipe_all: failed to read recovery record\n")); + return -1; + } + recovery_size = rec.rec_len + sizeof(rec); + } + + /* wipe the hashes */ + for (i=0;iheader.hash_size;i++) { + if (tdb1_ofs_write(tdb, TDB1_HASH_TOP(i), &offset) == -1) { + TDB1_LOG((tdb, TDB1_DEBUG_FATAL,"tdb1_wipe_all: failed to write hash %d\n", i)); + goto failed; + } + } + + /* wipe the freelist */ + if (tdb1_ofs_write(tdb, TDB1_FREELIST_TOP, &offset) == -1) { + TDB1_LOG((tdb, TDB1_DEBUG_FATAL,"tdb1_wipe_all: failed to write freelist\n")); + goto failed; + } + + /* add all the rest of the file to the freelist, possibly leaving a gap + for the recovery area */ + if (recovery_size == 0) { + /* the simple case - the whole file can be used as a freelist */ + data_len = (tdb->map_size - TDB1_DATA_START(tdb->header.hash_size)); + if (tdb1_free_region(tdb, TDB1_DATA_START(tdb->header.hash_size), data_len) != 0) { + goto failed; + } + } else { + /* we need to add two freelist entries - one on either + side of the recovery area + + Note that we cannot shift the recovery area during + this operation. Only the transaction.c code may + move the recovery area or we risk subtle data + corruption + */ + data_len = (recovery_head - TDB1_DATA_START(tdb->header.hash_size)); + if (tdb1_free_region(tdb, TDB1_DATA_START(tdb->header.hash_size), data_len) != 0) { + goto failed; + } + /* and the 2nd free list entry after the recovery area - if any */ + data_len = tdb->map_size - (recovery_head+recovery_size); + if (tdb1_free_region(tdb, recovery_head+recovery_size, data_len) != 0) { + goto failed; + } + } + + if (tdb1_unlockall(tdb) != 0) { + TDB1_LOG((tdb, TDB1_DEBUG_FATAL,"tdb1_wipe_all: failed to unlock\n")); + goto failed; + } + + return 0; + +failed: + tdb1_unlockall(tdb); + return -1; +} + +struct traverse_state { + bool error; + struct tdb1_context *dest_db; +}; + +/* + traverse function for repacking + */ +static int repack_traverse(struct tdb1_context *tdb, TDB1_DATA key, TDB1_DATA data, void *private_data) +{ + struct traverse_state *state = (struct traverse_state *)private_data; + if (tdb1_store(state->dest_db, key, data, TDB1_INSERT) != 0) { + state->error = true; + return -1; + } + return 0; +} + +/* + repack a tdb + */ +_PUBLIC_ int tdb1_repack(struct tdb1_context *tdb) +{ + struct tdb1_context *tmp_db; + struct traverse_state state; + + if (tdb1_transaction_start(tdb) != 0) { + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, __location__ " Failed to start transaction\n")); + return -1; + } + + tmp_db = tdb1_open("tmpdb", tdb1_hash_size(tdb), TDB1_INTERNAL, O_RDWR|O_CREAT, 0); + if (tmp_db == NULL) { + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, __location__ " Failed to create tmp_db\n")); + tdb1_transaction_cancel(tdb); + return -1; + } + + state.error = false; + state.dest_db = tmp_db; + + if (tdb1_traverse_read(tdb, repack_traverse, &state) == -1) { + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, __location__ " Failed to traverse copying out\n")); + tdb1_transaction_cancel(tdb); + tdb1_close(tmp_db); + return -1; + } + + if (state.error) { + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, __location__ " Error during traversal\n")); + tdb1_transaction_cancel(tdb); + tdb1_close(tmp_db); + return -1; + } + + if (tdb1_wipe_all(tdb) != 0) { + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, __location__ " Failed to wipe database\n")); + tdb1_transaction_cancel(tdb); + tdb1_close(tmp_db); + return -1; + } + + state.error = false; + state.dest_db = tdb; + + if (tdb1_traverse_read(tmp_db, repack_traverse, &state) == -1) { + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, __location__ " Failed to traverse copying back\n")); + tdb1_transaction_cancel(tdb); + tdb1_close(tmp_db); + return -1; + } + + if (state.error) { + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, __location__ " Error during second traversal\n")); + tdb1_transaction_cancel(tdb); + tdb1_close(tmp_db); + return -1; + } + + tdb1_close(tmp_db); + + if (tdb1_transaction_commit(tdb) != 0) { + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, __location__ " Failed to commit\n")); + return -1; + } + + return 0; +} + +/* Even on files, we can get partial writes due to signals. */ +bool tdb1_write_all(int fd, const void *buf, size_t count) +{ + while (count) { + ssize_t ret; + ret = write(fd, buf, count); + if (ret < 0) + return false; + buf = (const char *)buf + ret; + count -= ret; + } + return true; +} diff --git a/ccan/tdb2/tdb1_transaction.c b/ccan/tdb2/tdb1_transaction.c new file mode 100644 index 00000000..6c4c6f73 --- /dev/null +++ b/ccan/tdb2/tdb1_transaction.c @@ -0,0 +1,1271 @@ + /* + Unix SMB/CIFS implementation. + + trivial database library + + Copyright (C) Andrew Tridgell 2005 + + ** NOTE! The following LGPL license applies to the tdb + ** library. This does NOT imply that all of Samba is released + ** under the LGPL + + This library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 3 of the License, or (at your option) any later version. + + This library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with this library; if not, see . +*/ + +#include "tdb1_private.h" + +/* + transaction design: + + - only allow a single transaction at a time per database. This makes + using the transaction API simpler, as otherwise the caller would + have to cope with temporary failures in transactions that conflict + with other current transactions + + - keep the transaction recovery information in the same file as the + database, using a special 'transaction recovery' record pointed at + by the header. This removes the need for extra journal files as + used by some other databases + + - dynamically allocated the transaction recover record, re-using it + for subsequent transactions. If a larger record is needed then + tdb1_free() the old record to place it on the normal tdb freelist + before allocating the new record + + - during transactions, keep a linked list of writes all that have + been performed by intercepting all tdb1_write() calls. The hooked + transaction versions of tdb1_read() and tdb1_write() check this + linked list and try to use the elements of the list in preference + to the real database. + + - don't allow any locks to be held when a transaction starts, + otherwise we can end up with deadlock (plus lack of lock nesting + in posix locks would mean the lock is lost) + + - if the caller gains a lock during the transaction but doesn't + release it then fail the commit + + - allow for nested calls to tdb1_transaction_start(), re-using the + existing transaction record. If the inner transaction is cancelled + then a subsequent commit will fail + + - keep a mirrored copy of the tdb hash chain heads to allow for the + fast hash heads scan on traverse, updating the mirrored copy in + the transaction version of tdb1_write + + - allow callers to mix transaction and non-transaction use of tdb, + although once a transaction is started then an exclusive lock is + gained until the transaction is committed or cancelled + + - the commit stategy involves first saving away all modified data + into a linearised buffer in the transaction recovery area, then + marking the transaction recovery area with a magic value to + indicate a valid recovery record. In total 4 fsync/msync calls are + needed per commit to prevent race conditions. It might be possible + to reduce this to 3 or even 2 with some more work. + + - check for a valid recovery record on open of the tdb, while the + open lock is held. Automatically recover from the transaction + recovery area if needed, then continue with the open as + usual. This allows for smooth crash recovery with no administrator + intervention. + + - if TDB1_NOSYNC is passed to flags in tdb1_open then transactions are + still available, but no transaction recovery area is used and no + fsync/msync calls are made. + + - if TDB1_ALLOW_NESTING is passed to flags in tdb open, or added using + tdb1_add_flags() transaction nesting is enabled. + It resets the TDB1_DISALLOW_NESTING flag, as both cannot be used together. + The default is that transaction nesting is allowed. + Note: this default may change in future versions of tdb. + + Beware. when transactions are nested a transaction successfully + completed with tdb1_transaction_commit() can be silently unrolled later. + + - if TDB1_DISALLOW_NESTING is passed to flags in tdb open, or added using + tdb1_add_flags() transaction nesting is disabled. + It resets the TDB1_ALLOW_NESTING flag, as both cannot be used together. + An attempt create a nested transaction will fail with TDB1_ERR_NESTING. + The default is that transaction nesting is allowed. + Note: this default may change in future versions of tdb. +*/ + + +/* + hold the context of any current transaction +*/ +struct tdb1_transaction { + /* we keep a mirrored copy of the tdb hash heads here so + tdb1_next_hash_chain() can operate efficiently */ + uint32_t *hash_heads; + + /* the original io methods - used to do IOs to the real db */ + const struct tdb1_methods *io_methods; + + /* the list of transaction blocks. When a block is first + written to, it gets created in this list */ + uint8_t **blocks; + uint32_t num_blocks; + uint32_t block_size; /* bytes in each block */ + uint32_t last_block_size; /* number of valid bytes in the last block */ + + /* non-zero when an internal transaction error has + occurred. All write operations will then fail until the + transaction is ended */ + int transaction_error; + + /* when inside a transaction we need to keep track of any + nested tdb1_transaction_start() calls, as these are allowed, + but don't create a new transaction */ + int nesting; + + /* set when a prepare has already occurred */ + bool prepared; + tdb1_off_t magic_offset; + + /* old file size before transaction */ + tdb1_len_t old_map_size; + + /* did we expand in this transaction */ + bool expanded; +}; + + +/* + read while in a transaction. We need to check first if the data is in our list + of transaction elements, then if not do a real read +*/ +static int transaction1_read(struct tdb1_context *tdb, tdb1_off_t off, void *buf, + tdb1_len_t len, int cv) +{ + uint32_t blk; + + /* break it down into block sized ops */ + while (len + (off % tdb->transaction->block_size) > tdb->transaction->block_size) { + tdb1_len_t len2 = tdb->transaction->block_size - (off % tdb->transaction->block_size); + if (transaction1_read(tdb, off, buf, len2, cv) != 0) { + return -1; + } + len -= len2; + off += len2; + buf = (void *)(len2 + (char *)buf); + } + + if (len == 0) { + return 0; + } + + blk = off / tdb->transaction->block_size; + + /* see if we have it in the block list */ + if (tdb->transaction->num_blocks <= blk || + tdb->transaction->blocks[blk] == NULL) { + /* nope, do a real read */ + if (tdb->transaction->io_methods->tdb1_read(tdb, off, buf, len, cv) != 0) { + goto fail; + } + return 0; + } + + /* it is in the block list. Now check for the last block */ + if (blk == tdb->transaction->num_blocks-1) { + if (len > tdb->transaction->last_block_size) { + goto fail; + } + } + + /* now copy it out of this block */ + memcpy(buf, tdb->transaction->blocks[blk] + (off % tdb->transaction->block_size), len); + if (cv) { + tdb1_convert(buf, len); + } + return 0; + +fail: + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "transaction_read: failed at off=%d len=%d\n", off, len)); + tdb->ecode = TDB1_ERR_IO; + tdb->transaction->transaction_error = 1; + return -1; +} + + +/* + write while in a transaction +*/ +static int transaction1_write(struct tdb1_context *tdb, tdb1_off_t off, + const void *buf, tdb1_len_t len) +{ + uint32_t blk; + + /* Only a commit is allowed on a prepared transaction */ + if (tdb->transaction->prepared) { + tdb->ecode = TDB1_ERR_EINVAL; + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "transaction_write: transaction already prepared, write not allowed\n")); + tdb->transaction->transaction_error = 1; + return -1; + } + + /* if the write is to a hash head, then update the transaction + hash heads */ + if (len == sizeof(tdb1_off_t) && off >= TDB1_FREELIST_TOP && + off < TDB1_FREELIST_TOP+TDB1_HASHTABLE_SIZE(tdb)) { + uint32_t chain = (off-TDB1_FREELIST_TOP) / sizeof(tdb1_off_t); + memcpy(&tdb->transaction->hash_heads[chain], buf, len); + } + + /* break it up into block sized chunks */ + while (len + (off % tdb->transaction->block_size) > tdb->transaction->block_size) { + tdb1_len_t len2 = tdb->transaction->block_size - (off % tdb->transaction->block_size); + if (transaction1_write(tdb, off, buf, len2) != 0) { + return -1; + } + len -= len2; + off += len2; + if (buf != NULL) { + buf = (const void *)(len2 + (const char *)buf); + } + } + + if (len == 0) { + return 0; + } + + blk = off / tdb->transaction->block_size; + off = off % tdb->transaction->block_size; + + if (tdb->transaction->num_blocks <= blk) { + uint8_t **new_blocks; + /* expand the blocks array */ + if (tdb->transaction->blocks == NULL) { + new_blocks = (uint8_t **)malloc( + (blk+1)*sizeof(uint8_t *)); + } else { + new_blocks = (uint8_t **)realloc( + tdb->transaction->blocks, + (blk+1)*sizeof(uint8_t *)); + } + if (new_blocks == NULL) { + tdb->ecode = TDB1_ERR_OOM; + goto fail; + } + memset(&new_blocks[tdb->transaction->num_blocks], 0, + (1+(blk - tdb->transaction->num_blocks))*sizeof(uint8_t *)); + tdb->transaction->blocks = new_blocks; + tdb->transaction->num_blocks = blk+1; + tdb->transaction->last_block_size = 0; + } + + /* allocate and fill a block? */ + if (tdb->transaction->blocks[blk] == NULL) { + tdb->transaction->blocks[blk] = (uint8_t *)calloc(tdb->transaction->block_size, 1); + if (tdb->transaction->blocks[blk] == NULL) { + tdb->ecode = TDB1_ERR_OOM; + tdb->transaction->transaction_error = 1; + return -1; + } + if (tdb->transaction->old_map_size > blk * tdb->transaction->block_size) { + tdb1_len_t len2 = tdb->transaction->block_size; + if (len2 + (blk * tdb->transaction->block_size) > tdb->transaction->old_map_size) { + len2 = tdb->transaction->old_map_size - (blk * tdb->transaction->block_size); + } + if (tdb->transaction->io_methods->tdb1_read(tdb, blk * tdb->transaction->block_size, + tdb->transaction->blocks[blk], + len2, 0) != 0) { + SAFE_FREE(tdb->transaction->blocks[blk]); + tdb->ecode = TDB1_ERR_IO; + goto fail; + } + if (blk == tdb->transaction->num_blocks-1) { + tdb->transaction->last_block_size = len2; + } + } + } + + /* overwrite part of an existing block */ + if (buf == NULL) { + memset(tdb->transaction->blocks[blk] + off, 0, len); + } else { + memcpy(tdb->transaction->blocks[blk] + off, buf, len); + } + if (blk == tdb->transaction->num_blocks-1) { + if (len + off > tdb->transaction->last_block_size) { + tdb->transaction->last_block_size = len + off; + } + } + + return 0; + +fail: + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "transaction_write: failed at off=%d len=%d\n", + (blk*tdb->transaction->block_size) + off, len)); + tdb->transaction->transaction_error = 1; + return -1; +} + + +/* + write while in a transaction - this varient never expands the transaction blocks, it only + updates existing blocks. This means it cannot change the recovery size +*/ +static int transaction1_write_existing(struct tdb1_context *tdb, tdb1_off_t off, + const void *buf, tdb1_len_t len) +{ + uint32_t blk; + + /* break it up into block sized chunks */ + while (len + (off % tdb->transaction->block_size) > tdb->transaction->block_size) { + tdb1_len_t len2 = tdb->transaction->block_size - (off % tdb->transaction->block_size); + if (transaction1_write_existing(tdb, off, buf, len2) != 0) { + return -1; + } + len -= len2; + off += len2; + if (buf != NULL) { + buf = (const void *)(len2 + (const char *)buf); + } + } + + if (len == 0) { + return 0; + } + + blk = off / tdb->transaction->block_size; + off = off % tdb->transaction->block_size; + + if (tdb->transaction->num_blocks <= blk || + tdb->transaction->blocks[blk] == NULL) { + return 0; + } + + if (blk == tdb->transaction->num_blocks-1 && + off + len > tdb->transaction->last_block_size) { + if (off >= tdb->transaction->last_block_size) { + return 0; + } + len = tdb->transaction->last_block_size - off; + } + + /* overwrite part of an existing block */ + memcpy(tdb->transaction->blocks[blk] + off, buf, len); + + return 0; +} + + +/* + accelerated hash chain head search, using the cached hash heads +*/ +static void transaction1_next_hash_chain(struct tdb1_context *tdb, uint32_t *chain) +{ + uint32_t h = *chain; + for (;h < tdb->header.hash_size;h++) { + /* the +1 takes account of the freelist */ + if (0 != tdb->transaction->hash_heads[h+1]) { + break; + } + } + (*chain) = h; +} + +/* + out of bounds check during a transaction +*/ +static int transaction1_oob(struct tdb1_context *tdb, tdb1_off_t len, int probe) +{ + if (len <= tdb->map_size) { + return 0; + } + tdb->ecode = TDB1_ERR_IO; + return -1; +} + +/* + transaction version of tdb1_expand(). +*/ +static int transaction1_expand_file(struct tdb1_context *tdb, tdb1_off_t size, + tdb1_off_t addition) +{ + /* add a write to the transaction elements, so subsequent + reads see the zero data */ + if (transaction1_write(tdb, size, NULL, addition) != 0) { + return -1; + } + + tdb->transaction->expanded = true; + + return 0; +} + +static const struct tdb1_methods transaction1_methods = { + transaction1_read, + transaction1_write, + transaction1_next_hash_chain, + transaction1_oob, + transaction1_expand_file, +}; + + +/* + start a tdb transaction. No token is returned, as only a single + transaction is allowed to be pending per tdb1_context +*/ +static int _tdb1_transaction_start(struct tdb1_context *tdb, + enum tdb1_lock_flags lockflags) +{ + /* some sanity checks */ + if (tdb->read_only || (tdb->flags & TDB1_INTERNAL) || tdb->traverse_read) { + TDB1_LOG((tdb, TDB1_DEBUG_ERROR, "tdb1_transaction_start: cannot start a transaction on a read-only or internal db\n")); + tdb->ecode = TDB1_ERR_EINVAL; + return -1; + } + + /* cope with nested tdb1_transaction_start() calls */ + if (tdb->transaction != NULL) { + if (!(tdb->flags & TDB1_ALLOW_NESTING)) { + tdb->ecode = TDB1_ERR_NESTING; + return -1; + } + tdb->transaction->nesting++; + TDB1_LOG((tdb, TDB1_DEBUG_TRACE, "tdb1_transaction_start: nesting %d\n", + tdb->transaction->nesting)); + return 0; + } + + if (tdb1_have_extra_locks(tdb)) { + /* the caller must not have any locks when starting a + transaction as otherwise we'll be screwed by lack + of nested locks in posix */ + TDB1_LOG((tdb, TDB1_DEBUG_ERROR, "tdb1_transaction_start: cannot start a transaction with locks held\n")); + tdb->ecode = TDB1_ERR_LOCK; + return -1; + } + + if (tdb->travlocks.next != NULL) { + /* you cannot use transactions inside a traverse (although you can use + traverse inside a transaction) as otherwise you can end up with + deadlock */ + TDB1_LOG((tdb, TDB1_DEBUG_ERROR, "tdb1_transaction_start: cannot start a transaction within a traverse\n")); + tdb->ecode = TDB1_ERR_LOCK; + return -1; + } + + tdb->transaction = (struct tdb1_transaction *) + calloc(sizeof(struct tdb1_transaction), 1); + if (tdb->transaction == NULL) { + tdb->ecode = TDB1_ERR_OOM; + return -1; + } + + /* a page at a time seems like a reasonable compromise between compactness and efficiency */ + tdb->transaction->block_size = tdb->page_size; + + /* get the transaction write lock. This is a blocking lock. As + discussed with Volker, there are a number of ways we could + make this async, which we will probably do in the future */ + if (tdb1_transaction_lock(tdb, F_WRLCK, lockflags) == -1) { + SAFE_FREE(tdb->transaction->blocks); + SAFE_FREE(tdb->transaction); + if ((lockflags & TDB1_LOCK_WAIT) == 0) { + tdb->ecode = TDB1_ERR_NOLOCK; + } + return -1; + } + + /* get a read lock from the freelist to the end of file. This + is upgraded to a write lock during the commit */ + if (tdb1_allrecord_lock(tdb, F_RDLCK, TDB1_LOCK_WAIT, true) == -1) { + TDB1_LOG((tdb, TDB1_DEBUG_ERROR, "tdb1_transaction_start: failed to get hash locks\n")); + goto fail_allrecord_lock; + } + + /* setup a copy of the hash table heads so the hash scan in + traverse can be fast */ + tdb->transaction->hash_heads = (uint32_t *) + calloc(tdb->header.hash_size+1, sizeof(uint32_t)); + if (tdb->transaction->hash_heads == NULL) { + tdb->ecode = TDB1_ERR_OOM; + goto fail; + } + if (tdb->methods->tdb1_read(tdb, TDB1_FREELIST_TOP, tdb->transaction->hash_heads, + TDB1_HASHTABLE_SIZE(tdb), 0) != 0) { + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "tdb1_transaction_start: failed to read hash heads\n")); + tdb->ecode = TDB1_ERR_IO; + goto fail; + } + + /* make sure we know about any file expansions already done by + anyone else */ + tdb->methods->tdb1_oob(tdb, tdb->map_size + 1, 1); + tdb->transaction->old_map_size = tdb->map_size; + + /* finally hook the io methods, replacing them with + transaction specific methods */ + tdb->transaction->io_methods = tdb->methods; + tdb->methods = &transaction1_methods; + + return 0; + +fail: + tdb1_allrecord_unlock(tdb, F_RDLCK, false); +fail_allrecord_lock: + tdb1_transaction_unlock(tdb, F_WRLCK); + SAFE_FREE(tdb->transaction->blocks); + SAFE_FREE(tdb->transaction->hash_heads); + SAFE_FREE(tdb->transaction); + return -1; +} + +_PUBLIC_ int tdb1_transaction_start(struct tdb1_context *tdb) +{ + return _tdb1_transaction_start(tdb, TDB1_LOCK_WAIT); +} + +_PUBLIC_ int tdb1_transaction_start_nonblock(struct tdb1_context *tdb) +{ + return _tdb1_transaction_start(tdb, TDB1_LOCK_NOWAIT|TDB1_LOCK_PROBE); +} + +/* + sync to disk +*/ +static int transaction1_sync(struct tdb1_context *tdb, tdb1_off_t offset, tdb1_len_t length) +{ + if (tdb->flags & TDB1_NOSYNC) { + return 0; + } + +#if HAVE_FDATASYNC + if (fdatasync(tdb->fd) != 0) { +#else + if (fsync(tdb->fd) != 0) { +#endif + tdb->ecode = TDB1_ERR_IO; + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "tdb1_transaction: fsync failed\n")); + return -1; + } +#if HAVE_MMAP + if (tdb->map_ptr) { + tdb1_off_t moffset = offset & ~(tdb->page_size-1); + if (msync(moffset + (char *)tdb->map_ptr, + length + (offset - moffset), MS_SYNC) != 0) { + tdb->ecode = TDB1_ERR_IO; + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "tdb1_transaction: msync failed - %s\n", + strerror(errno))); + return -1; + } + } +#endif + return 0; +} + + +static int _tdb1_transaction_cancel(struct tdb1_context *tdb) +{ + int i, ret = 0; + + if (tdb->transaction == NULL) { + TDB1_LOG((tdb, TDB1_DEBUG_ERROR, "tdb1_transaction_cancel: no transaction\n")); + return -1; + } + + if (tdb->transaction->nesting != 0) { + tdb->transaction->transaction_error = 1; + tdb->transaction->nesting--; + return 0; + } + + tdb->map_size = tdb->transaction->old_map_size; + + /* free all the transaction blocks */ + for (i=0;itransaction->num_blocks;i++) { + if (tdb->transaction->blocks[i] != NULL) { + free(tdb->transaction->blocks[i]); + } + } + SAFE_FREE(tdb->transaction->blocks); + + if (tdb->transaction->magic_offset) { + const struct tdb1_methods *methods = tdb->transaction->io_methods; + const uint32_t invalid = TDB1_RECOVERY_INVALID_MAGIC; + + /* remove the recovery marker */ + if (methods->tdb1_write(tdb, tdb->transaction->magic_offset, &invalid, 4) == -1 || + transaction1_sync(tdb, tdb->transaction->magic_offset, 4) == -1) { + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "tdb1_transaction_cancel: failed to remove recovery magic\n")); + ret = -1; + } + } + + /* This also removes the OPEN_LOCK, if we have it. */ + tdb1_release_transaction_locks(tdb); + + /* restore the normal io methods */ + tdb->methods = tdb->transaction->io_methods; + + SAFE_FREE(tdb->transaction->hash_heads); + SAFE_FREE(tdb->transaction); + + return ret; +} + +/* + cancel the current transaction +*/ +_PUBLIC_ int tdb1_transaction_cancel(struct tdb1_context *tdb) +{ + return _tdb1_transaction_cancel(tdb); +} + +/* + work out how much space the linearised recovery data will consume +*/ +static tdb1_len_t tdb1_recovery_size(struct tdb1_context *tdb) +{ + tdb1_len_t recovery_size = 0; + int i; + + recovery_size = sizeof(uint32_t); + for (i=0;itransaction->num_blocks;i++) { + if (i * tdb->transaction->block_size >= tdb->transaction->old_map_size) { + break; + } + if (tdb->transaction->blocks[i] == NULL) { + continue; + } + recovery_size += 2*sizeof(tdb1_off_t); + if (i == tdb->transaction->num_blocks-1) { + recovery_size += tdb->transaction->last_block_size; + } else { + recovery_size += tdb->transaction->block_size; + } + } + + return recovery_size; +} + +int tdb1_recovery_area(struct tdb1_context *tdb, + const struct tdb1_methods *methods, + tdb1_off_t *recovery_offset, + struct tdb1_record *rec) +{ + if (tdb1_ofs_read(tdb, TDB1_RECOVERY_HEAD, recovery_offset) == -1) { + return -1; + } + + if (*recovery_offset == 0) { + rec->rec_len = 0; + return 0; + } + + if (methods->tdb1_read(tdb, *recovery_offset, rec, sizeof(*rec), + TDB1_DOCONV()) == -1) { + return -1; + } + + /* ignore invalid recovery regions: can happen in crash */ + if (rec->magic != TDB1_RECOVERY_MAGIC && + rec->magic != TDB1_RECOVERY_INVALID_MAGIC) { + *recovery_offset = 0; + rec->rec_len = 0; + } + return 0; +} + +/* + allocate the recovery area, or use an existing recovery area if it is + large enough +*/ +static int tdb1_recovery_allocate(struct tdb1_context *tdb, + tdb1_len_t *recovery_size, + tdb1_off_t *recovery_offset, + tdb1_len_t *recovery_max_size) +{ + struct tdb1_record rec; + const struct tdb1_methods *methods = tdb->transaction->io_methods; + tdb1_off_t recovery_head; + + if (tdb1_recovery_area(tdb, methods, &recovery_head, &rec) == -1) { + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "tdb1_recovery_allocate: failed to read recovery head\n")); + return -1; + } + + *recovery_size = tdb1_recovery_size(tdb); + + if (recovery_head != 0 && *recovery_size <= rec.rec_len) { + /* it fits in the existing area */ + *recovery_max_size = rec.rec_len; + *recovery_offset = recovery_head; + return 0; + } + + /* we need to free up the old recovery area, then allocate a + new one at the end of the file. Note that we cannot use + tdb1_allocate() to allocate the new one as that might return + us an area that is being currently used (as of the start of + the transaction) */ + if (recovery_head != 0) { + if (tdb1_free(tdb, recovery_head, &rec) == -1) { + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "tdb1_recovery_allocate: failed to free previous recovery area\n")); + return -1; + } + } + + /* the tdb1_free() call might have increased the recovery size */ + *recovery_size = tdb1_recovery_size(tdb); + + /* round up to a multiple of page size */ + *recovery_max_size = TDB1_ALIGN(sizeof(rec) + *recovery_size, tdb->page_size) - sizeof(rec); + *recovery_offset = tdb->map_size; + recovery_head = *recovery_offset; + + if (methods->tdb1_expand_file(tdb, tdb->transaction->old_map_size, + (tdb->map_size - tdb->transaction->old_map_size) + + sizeof(rec) + *recovery_max_size) == -1) { + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "tdb1_recovery_allocate: failed to create recovery area\n")); + return -1; + } + + /* remap the file (if using mmap) */ + methods->tdb1_oob(tdb, tdb->map_size + 1, 1); + + /* we have to reset the old map size so that we don't try to expand the file + again in the transaction commit, which would destroy the recovery area */ + tdb->transaction->old_map_size = tdb->map_size; + + /* write the recovery header offset and sync - we can sync without a race here + as the magic ptr in the recovery record has not been set */ + TDB1_CONV(recovery_head); + if (methods->tdb1_write(tdb, TDB1_RECOVERY_HEAD, + &recovery_head, sizeof(tdb1_off_t)) == -1) { + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "tdb1_recovery_allocate: failed to write recovery head\n")); + return -1; + } + if (transaction1_write_existing(tdb, TDB1_RECOVERY_HEAD, &recovery_head, sizeof(tdb1_off_t)) == -1) { + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "tdb1_recovery_allocate: failed to write recovery head\n")); + return -1; + } + + return 0; +} + + +/* + setup the recovery data that will be used on a crash during commit +*/ +static int transaction1_setup_recovery(struct tdb1_context *tdb, + tdb1_off_t *magic_offset) +{ + tdb1_len_t recovery_size; + unsigned char *data, *p; + const struct tdb1_methods *methods = tdb->transaction->io_methods; + struct tdb1_record *rec; + tdb1_off_t recovery_offset, recovery_max_size; + tdb1_off_t old_map_size = tdb->transaction->old_map_size; + uint32_t magic, tailer; + int i; + + /* + check that the recovery area has enough space + */ + if (tdb1_recovery_allocate(tdb, &recovery_size, + &recovery_offset, &recovery_max_size) == -1) { + return -1; + } + + data = (unsigned char *)malloc(recovery_size + sizeof(*rec)); + if (data == NULL) { + tdb->ecode = TDB1_ERR_OOM; + return -1; + } + + rec = (struct tdb1_record *)data; + memset(rec, 0, sizeof(*rec)); + + rec->magic = TDB1_RECOVERY_INVALID_MAGIC; + rec->data_len = recovery_size; + rec->rec_len = recovery_max_size; + rec->key_len = old_map_size; + TDB1_CONV(*rec); + + /* build the recovery data into a single blob to allow us to do a single + large write, which should be more efficient */ + p = data + sizeof(*rec); + for (i=0;itransaction->num_blocks;i++) { + tdb1_off_t offset; + tdb1_len_t length; + + if (tdb->transaction->blocks[i] == NULL) { + continue; + } + + offset = i * tdb->transaction->block_size; + length = tdb->transaction->block_size; + if (i == tdb->transaction->num_blocks-1) { + length = tdb->transaction->last_block_size; + } + + if (offset >= old_map_size) { + continue; + } + if (offset + length > tdb->transaction->old_map_size) { + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "tdb1_transaction_setup_recovery: transaction data over new region boundary\n")); + free(data); + tdb->ecode = TDB1_ERR_CORRUPT; + return -1; + } + memcpy(p, &offset, 4); + memcpy(p+4, &length, 4); + if (TDB1_DOCONV()) { + tdb1_convert(p, 8); + } + /* the recovery area contains the old data, not the + new data, so we have to call the original tdb1_read + method to get it */ + if (methods->tdb1_read(tdb, offset, p + 8, length, 0) != 0) { + free(data); + tdb->ecode = TDB1_ERR_IO; + return -1; + } + p += 8 + length; + } + + /* and the tailer */ + tailer = sizeof(*rec) + recovery_max_size; + memcpy(p, &tailer, 4); + if (TDB1_DOCONV()) { + tdb1_convert(p, 4); + } + + /* write the recovery data to the recovery area */ + if (methods->tdb1_write(tdb, recovery_offset, data, sizeof(*rec) + recovery_size) == -1) { + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "tdb1_transaction_setup_recovery: failed to write recovery data\n")); + free(data); + tdb->ecode = TDB1_ERR_IO; + return -1; + } + if (transaction1_write_existing(tdb, recovery_offset, data, sizeof(*rec) + recovery_size) == -1) { + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "tdb1_transaction_setup_recovery: failed to write secondary recovery data\n")); + free(data); + tdb->ecode = TDB1_ERR_IO; + return -1; + } + + /* as we don't have ordered writes, we have to sync the recovery + data before we update the magic to indicate that the recovery + data is present */ + if (transaction1_sync(tdb, recovery_offset, sizeof(*rec) + recovery_size) == -1) { + free(data); + return -1; + } + + free(data); + + magic = TDB1_RECOVERY_MAGIC; + TDB1_CONV(magic); + + *magic_offset = recovery_offset + offsetof(struct tdb1_record, magic); + + if (methods->tdb1_write(tdb, *magic_offset, &magic, sizeof(magic)) == -1) { + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "tdb1_transaction_setup_recovery: failed to write recovery magic\n")); + tdb->ecode = TDB1_ERR_IO; + return -1; + } + if (transaction1_write_existing(tdb, *magic_offset, &magic, sizeof(magic)) == -1) { + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "tdb1_transaction_setup_recovery: failed to write secondary recovery magic\n")); + tdb->ecode = TDB1_ERR_IO; + return -1; + } + + /* ensure the recovery magic marker is on disk */ + if (transaction1_sync(tdb, *magic_offset, sizeof(magic)) == -1) { + return -1; + } + + return 0; +} + +static int _tdb1_transaction_prepare_commit(struct tdb1_context *tdb) +{ + const struct tdb1_methods *methods; + + if (tdb->transaction == NULL) { + TDB1_LOG((tdb, TDB1_DEBUG_ERROR, "tdb1_transaction_prepare_commit: no transaction\n")); + return -1; + } + + if (tdb->transaction->prepared) { + tdb->ecode = TDB1_ERR_EINVAL; + _tdb1_transaction_cancel(tdb); + TDB1_LOG((tdb, TDB1_DEBUG_ERROR, "tdb1_transaction_prepare_commit: transaction already prepared\n")); + return -1; + } + + if (tdb->transaction->transaction_error) { + tdb->ecode = TDB1_ERR_IO; + _tdb1_transaction_cancel(tdb); + TDB1_LOG((tdb, TDB1_DEBUG_ERROR, "tdb1_transaction_prepare_commit: transaction error pending\n")); + return -1; + } + + + if (tdb->transaction->nesting != 0) { + return 0; + } + + /* check for a null transaction */ + if (tdb->transaction->blocks == NULL) { + return 0; + } + + methods = tdb->transaction->io_methods; + + /* if there are any locks pending then the caller has not + nested their locks properly, so fail the transaction */ + if (tdb1_have_extra_locks(tdb)) { + tdb->ecode = TDB1_ERR_LOCK; + TDB1_LOG((tdb, TDB1_DEBUG_ERROR, "tdb1_transaction_prepare_commit: locks pending on commit\n")); + _tdb1_transaction_cancel(tdb); + return -1; + } + + /* upgrade the main transaction lock region to a write lock */ + if (tdb1_allrecord_upgrade(tdb) == -1) { + TDB1_LOG((tdb, TDB1_DEBUG_ERROR, "tdb1_transaction_prepare_commit: failed to upgrade hash locks\n")); + _tdb1_transaction_cancel(tdb); + return -1; + } + + /* get the open lock - this prevents new users attaching to the database + during the commit */ + if (tdb1_nest_lock(tdb, TDB1_OPEN_LOCK, F_WRLCK, TDB1_LOCK_WAIT) == -1) { + TDB1_LOG((tdb, TDB1_DEBUG_ERROR, "tdb1_transaction_prepare_commit: failed to get open lock\n")); + _tdb1_transaction_cancel(tdb); + return -1; + } + + if (!(tdb->flags & TDB1_NOSYNC)) { + /* write the recovery data to the end of the file */ + if (transaction1_setup_recovery(tdb, &tdb->transaction->magic_offset) == -1) { + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "tdb1_transaction_prepare_commit: failed to setup recovery data\n")); + _tdb1_transaction_cancel(tdb); + return -1; + } + } + + tdb->transaction->prepared = true; + + /* expand the file to the new size if needed */ + if (tdb->map_size != tdb->transaction->old_map_size) { + if (methods->tdb1_expand_file(tdb, tdb->transaction->old_map_size, + tdb->map_size - + tdb->transaction->old_map_size) == -1) { + tdb->ecode = TDB1_ERR_IO; + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "tdb1_transaction_prepare_commit: expansion failed\n")); + _tdb1_transaction_cancel(tdb); + return -1; + } + tdb->map_size = tdb->transaction->old_map_size; + methods->tdb1_oob(tdb, tdb->map_size + 1, 1); + } + + /* Keep the open lock until the actual commit */ + + return 0; +} + +/* + prepare to commit the current transaction +*/ +_PUBLIC_ int tdb1_transaction_prepare_commit(struct tdb1_context *tdb) +{ + return _tdb1_transaction_prepare_commit(tdb); +} + +/* A repack is worthwhile if the largest is less than half total free. */ +static bool repack_worthwhile(struct tdb1_context *tdb) +{ + tdb1_off_t ptr; + struct tdb1_record rec; + tdb1_len_t total = 0, largest = 0; + + if (tdb1_ofs_read(tdb, TDB1_FREELIST_TOP, &ptr) == -1) { + return false; + } + + while (ptr != 0 && tdb1_rec_free_read(tdb, ptr, &rec) == 0) { + total += rec.rec_len; + if (rec.rec_len > largest) { + largest = rec.rec_len; + } + ptr = rec.next; + } + + return total > largest * 2; +} + +/* + commit the current transaction +*/ +_PUBLIC_ int tdb1_transaction_commit(struct tdb1_context *tdb) +{ + const struct tdb1_methods *methods; + int i; + bool need_repack = false; + + if (tdb->transaction == NULL) { + TDB1_LOG((tdb, TDB1_DEBUG_ERROR, "tdb1_transaction_commit: no transaction\n")); + return -1; + } + + if (tdb->transaction->transaction_error) { + tdb->ecode = TDB1_ERR_IO; + _tdb1_transaction_cancel(tdb); + TDB1_LOG((tdb, TDB1_DEBUG_ERROR, "tdb1_transaction_commit: transaction error pending\n")); + return -1; + } + + + if (tdb->transaction->nesting != 0) { + tdb->transaction->nesting--; + return 0; + } + + /* check for a null transaction */ + if (tdb->transaction->blocks == NULL) { + _tdb1_transaction_cancel(tdb); + return 0; + } + + if (!tdb->transaction->prepared) { + int ret = _tdb1_transaction_prepare_commit(tdb); + if (ret) + return ret; + } + + methods = tdb->transaction->io_methods; + + /* perform all the writes */ + for (i=0;itransaction->num_blocks;i++) { + tdb1_off_t offset; + tdb1_len_t length; + + if (tdb->transaction->blocks[i] == NULL) { + continue; + } + + offset = i * tdb->transaction->block_size; + length = tdb->transaction->block_size; + if (i == tdb->transaction->num_blocks-1) { + length = tdb->transaction->last_block_size; + } + + if (methods->tdb1_write(tdb, offset, tdb->transaction->blocks[i], length) == -1) { + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "tdb1_transaction_commit: write failed during commit\n")); + + /* we've overwritten part of the data and + possibly expanded the file, so we need to + run the crash recovery code */ + tdb->methods = methods; + tdb1_transaction_recover(tdb); + + _tdb1_transaction_cancel(tdb); + + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "tdb1_transaction_commit: write failed\n")); + return -1; + } + SAFE_FREE(tdb->transaction->blocks[i]); + } + + /* Do this before we drop lock or blocks. */ + if (tdb->transaction->expanded) { + need_repack = repack_worthwhile(tdb); + } + + SAFE_FREE(tdb->transaction->blocks); + tdb->transaction->num_blocks = 0; + + /* ensure the new data is on disk */ + if (transaction1_sync(tdb, 0, tdb->map_size) == -1) { + return -1; + } + + /* + TODO: maybe write to some dummy hdr field, or write to magic + offset without mmap, before the last sync, instead of the + utime() call + */ + + /* on some systems (like Linux 2.6.x) changes via mmap/msync + don't change the mtime of the file, this means the file may + not be backed up (as tdb rounding to block sizes means that + file size changes are quite rare too). The following forces + mtime changes when a transaction completes */ +#if HAVE_UTIME + utime(tdb->name, NULL); +#endif + + /* use a transaction cancel to free memory and remove the + transaction locks */ + _tdb1_transaction_cancel(tdb); + + if (need_repack) { + return tdb1_repack(tdb); + } + + return 0; +} + + +/* + recover from an aborted transaction. Must be called with exclusive + database write access already established (including the open + lock to prevent new processes attaching) +*/ +int tdb1_transaction_recover(struct tdb1_context *tdb) +{ + tdb1_off_t recovery_head, recovery_eof; + unsigned char *data, *p; + uint32_t zero = 0; + struct tdb1_record rec; + + /* find the recovery area */ + if (tdb1_ofs_read(tdb, TDB1_RECOVERY_HEAD, &recovery_head) == -1) { + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "tdb1_transaction_recover: failed to read recovery head\n")); + tdb->ecode = TDB1_ERR_IO; + return -1; + } + + if (recovery_head == 0) { + /* we have never allocated a recovery record */ + return 0; + } + + /* read the recovery record */ + if (tdb->methods->tdb1_read(tdb, recovery_head, &rec, + sizeof(rec), TDB1_DOCONV()) == -1) { + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "tdb1_transaction_recover: failed to read recovery record\n")); + tdb->ecode = TDB1_ERR_IO; + return -1; + } + + if (rec.magic != TDB1_RECOVERY_MAGIC) { + /* there is no valid recovery data */ + return 0; + } + + if (tdb->read_only) { + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "tdb1_transaction_recover: attempt to recover read only database\n")); + tdb->ecode = TDB1_ERR_CORRUPT; + return -1; + } + + recovery_eof = rec.key_len; + + data = (unsigned char *)malloc(rec.data_len); + if (data == NULL) { + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "tdb1_transaction_recover: failed to allocate recovery data\n")); + tdb->ecode = TDB1_ERR_OOM; + return -1; + } + + /* read the full recovery data */ + if (tdb->methods->tdb1_read(tdb, recovery_head + sizeof(rec), data, + rec.data_len, 0) == -1) { + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "tdb1_transaction_recover: failed to read recovery data\n")); + tdb->ecode = TDB1_ERR_IO; + return -1; + } + + /* recover the file data */ + p = data; + while (p+8 < data + rec.data_len) { + uint32_t ofs, len; + if (TDB1_DOCONV()) { + tdb1_convert(p, 8); + } + memcpy(&ofs, p, 4); + memcpy(&len, p+4, 4); + + if (tdb->methods->tdb1_write(tdb, ofs, p+8, len) == -1) { + free(data); + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "tdb1_transaction_recover: failed to recover %d bytes at offset %d\n", len, ofs)); + tdb->ecode = TDB1_ERR_IO; + return -1; + } + p += 8 + len; + } + + free(data); + + if (transaction1_sync(tdb, 0, tdb->map_size) == -1) { + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "tdb1_transaction_recover: failed to sync recovery\n")); + tdb->ecode = TDB1_ERR_IO; + return -1; + } + + /* if the recovery area is after the recovered eof then remove it */ + if (recovery_eof <= recovery_head) { + if (tdb1_ofs_write(tdb, TDB1_RECOVERY_HEAD, &zero) == -1) { + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "tdb1_transaction_recover: failed to remove recovery head\n")); + tdb->ecode = TDB1_ERR_IO; + return -1; + } + } + + /* remove the recovery magic */ + if (tdb1_ofs_write(tdb, recovery_head + offsetof(struct tdb1_record, magic), + &zero) == -1) { + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "tdb1_transaction_recover: failed to remove recovery magic\n")); + tdb->ecode = TDB1_ERR_IO; + return -1; + } + + if (transaction1_sync(tdb, 0, recovery_eof) == -1) { + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "tdb1_transaction_recover: failed to sync2 recovery\n")); + tdb->ecode = TDB1_ERR_IO; + return -1; + } + + TDB1_LOG((tdb, TDB1_DEBUG_TRACE, "tdb1_transaction_recover: recovered %d byte database\n", + recovery_eof)); + + /* all done */ + return 0; +} + +/* Any I/O failures we say "needs recovery". */ +bool tdb1_needs_recovery(struct tdb1_context *tdb) +{ + tdb1_off_t recovery_head; + struct tdb1_record rec; + + /* find the recovery area */ + if (tdb1_ofs_read(tdb, TDB1_RECOVERY_HEAD, &recovery_head) == -1) { + return true; + } + + if (recovery_head == 0) { + /* we have never allocated a recovery record */ + return false; + } + + /* read the recovery record */ + if (tdb->methods->tdb1_read(tdb, recovery_head, &rec, + sizeof(rec), TDB1_DOCONV()) == -1) { + return true; + } + + return (rec.magic == TDB1_RECOVERY_MAGIC); +} diff --git a/ccan/tdb2/tdb1_traverse.c b/ccan/tdb2/tdb1_traverse.c new file mode 100644 index 00000000..515beb1f --- /dev/null +++ b/ccan/tdb2/tdb1_traverse.c @@ -0,0 +1,352 @@ + /* + Unix SMB/CIFS implementation. + + trivial database library + + Copyright (C) Andrew Tridgell 1999-2005 + Copyright (C) Paul `Rusty' Russell 2000 + Copyright (C) Jeremy Allison 2000-2003 + + ** NOTE! The following LGPL license applies to the tdb + ** library. This does NOT imply that all of Samba is released + ** under the LGPL + + This library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 3 of the License, or (at your option) any later version. + + This library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with this library; if not, see . +*/ + +#include "tdb1_private.h" + +#define TDB1_NEXT_LOCK_ERR ((tdb1_off_t)-1) + +/* Uses traverse lock: 0 = finish, TDB1_NEXT_LOCK_ERR = error, + other = record offset */ +static tdb1_off_t tdb1_next_lock(struct tdb1_context *tdb, struct tdb1_traverse_lock *tlock, + struct tdb1_record *rec) +{ + int want_next = (tlock->off != 0); + + /* Lock each chain from the start one. */ + for (; tlock->hash < tdb->header.hash_size; tlock->hash++) { + if (!tlock->off && tlock->hash != 0) { + /* this is an optimisation for the common case where + the hash chain is empty, which is particularly + common for the use of tdb with ldb, where large + hashes are used. In that case we spend most of our + time in tdb1_brlock(), locking empty hash chains. + + To avoid this, we do an unlocked pre-check to see + if the hash chain is empty before starting to look + inside it. If it is empty then we can avoid that + hash chain. If it isn't empty then we can't believe + the value we get back, as we read it without a + lock, so instead we get the lock and re-fetch the + value below. + + Notice that not doing this optimisation on the + first hash chain is critical. We must guarantee + that we have done at least one fcntl lock at the + start of a search to guarantee that memory is + coherent on SMP systems. If records are added by + others during the search then thats OK, and we + could possibly miss those with this trick, but we + could miss them anyway without this trick, so the + semantics don't change. + + With a non-indexed ldb search this trick gains us a + factor of around 80 in speed on a linux 2.6.x + system (testing using ldbtest). + */ + tdb->methods->next_hash_chain(tdb, &tlock->hash); + if (tlock->hash == tdb->header.hash_size) { + continue; + } + } + + if (tdb1_lock(tdb, tlock->hash, tlock->lock_rw) == -1) + return TDB1_NEXT_LOCK_ERR; + + /* No previous record? Start at top of chain. */ + if (!tlock->off) { + if (tdb1_ofs_read(tdb, TDB1_HASH_TOP(tlock->hash), + &tlock->off) == -1) + goto fail; + } else { + /* Otherwise unlock the previous record. */ + if (tdb1_unlock_record(tdb, tlock->off) != 0) + goto fail; + } + + if (want_next) { + /* We have offset of old record: grab next */ + if (tdb1_rec_read(tdb, tlock->off, rec) == -1) + goto fail; + tlock->off = rec->next; + } + + /* Iterate through chain */ + while( tlock->off) { + tdb1_off_t current; + if (tdb1_rec_read(tdb, tlock->off, rec) == -1) + goto fail; + + /* Detect infinite loops. From "Shlomi Yaakobovich" . */ + if (tlock->off == rec->next) { + tdb->ecode = TDB1_ERR_CORRUPT; + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "tdb1_next_lock: loop detected.\n")); + goto fail; + } + + if (!TDB1_DEAD(rec)) { + /* Woohoo: we found one! */ + if (tdb1_lock_record(tdb, tlock->off) != 0) + goto fail; + return tlock->off; + } + + /* Try to clean dead ones from old traverses */ + current = tlock->off; + tlock->off = rec->next; + if (!(tdb->read_only || tdb->traverse_read) && + tdb1_do_delete(tdb, current, rec) != 0) + goto fail; + } + tdb1_unlock(tdb, tlock->hash, tlock->lock_rw); + want_next = 0; + } + /* We finished iteration without finding anything */ + tdb->ecode = TDB1_SUCCESS; + return 0; + + fail: + tlock->off = 0; + if (tdb1_unlock(tdb, tlock->hash, tlock->lock_rw) != 0) + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "tdb1_next_lock: On error unlock failed!\n")); + return TDB1_NEXT_LOCK_ERR; +} + +/* traverse the entire database - calling fn(tdb, key, data) on each element. + return -1 on error or the record count traversed + if fn is NULL then it is not called + a non-zero return value from fn() indicates that the traversal should stop + */ +static int tdb1_traverse_internal(struct tdb1_context *tdb, + tdb1_traverse_func fn, void *private_data, + struct tdb1_traverse_lock *tl) +{ + TDB1_DATA key, dbuf; + struct tdb1_record rec; + int ret = 0, count = 0; + tdb1_off_t off; + + /* This was in the initializaton, above, but the IRIX compiler + * did not like it. crh + */ + tl->next = tdb->travlocks.next; + + /* fcntl locks don't stack: beware traverse inside traverse */ + tdb->travlocks.next = tl; + + /* tdb1_next_lock places locks on the record returned, and its chain */ + while ((off = tdb1_next_lock(tdb, tl, &rec)) != 0) { + if (off == TDB1_NEXT_LOCK_ERR) { + ret = -1; + goto out; + } + count++; + /* now read the full record */ + key.dptr = tdb1_alloc_read(tdb, tl->off + sizeof(rec), + rec.key_len + rec.data_len); + if (!key.dptr) { + ret = -1; + if (tdb1_unlock(tdb, tl->hash, tl->lock_rw) != 0) + goto out; + if (tdb1_unlock_record(tdb, tl->off) != 0) + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "tdb1_traverse: key.dptr == NULL and unlock_record failed!\n")); + goto out; + } + key.dsize = rec.key_len; + dbuf.dptr = key.dptr + rec.key_len; + dbuf.dsize = rec.data_len; + + /* Drop chain lock, call out */ + if (tdb1_unlock(tdb, tl->hash, tl->lock_rw) != 0) { + ret = -1; + SAFE_FREE(key.dptr); + goto out; + } + if (fn && fn(tdb, key, dbuf, private_data)) { + /* They want us to terminate traversal */ + if (tdb1_unlock_record(tdb, tl->off) != 0) { + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "tdb1_traverse: unlock_record failed!\n"));; + ret = -1; + } + SAFE_FREE(key.dptr); + goto out; + } + SAFE_FREE(key.dptr); + } +out: + tdb->travlocks.next = tl->next; + if (ret < 0) + return -1; + else + return count; +} + + +/* + a write style traverse - temporarily marks the db read only +*/ +_PUBLIC_ int tdb1_traverse_read(struct tdb1_context *tdb, + tdb1_traverse_func fn, void *private_data) +{ + struct tdb1_traverse_lock tl = { NULL, 0, 0, F_RDLCK }; + int ret; + + /* we need to get a read lock on the transaction lock here to + cope with the lock ordering semantics of solaris10 */ + if (tdb1_transaction_lock(tdb, F_RDLCK, TDB1_LOCK_WAIT)) { + return -1; + } + + tdb->traverse_read++; + ret = tdb1_traverse_internal(tdb, fn, private_data, &tl); + tdb->traverse_read--; + + tdb1_transaction_unlock(tdb, F_RDLCK); + + return ret; +} + +/* + a write style traverse - needs to get the transaction lock to + prevent deadlocks + + WARNING: The data buffer given to the callback fn does NOT meet the + alignment restrictions malloc gives you. +*/ +_PUBLIC_ int tdb1_traverse(struct tdb1_context *tdb, + tdb1_traverse_func fn, void *private_data) +{ + struct tdb1_traverse_lock tl = { NULL, 0, 0, F_WRLCK }; + int ret; + + if (tdb->read_only || tdb->traverse_read) { + return tdb1_traverse_read(tdb, fn, private_data); + } + + if (tdb1_transaction_lock(tdb, F_WRLCK, TDB1_LOCK_WAIT)) { + return -1; + } + + tdb->traverse_write++; + ret = tdb1_traverse_internal(tdb, fn, private_data, &tl); + tdb->traverse_write--; + + tdb1_transaction_unlock(tdb, F_WRLCK); + + return ret; +} + + +/* find the first entry in the database and return its key */ +_PUBLIC_ TDB1_DATA tdb1_firstkey(struct tdb1_context *tdb) +{ + TDB1_DATA key; + struct tdb1_record rec; + tdb1_off_t off; + + /* release any old lock */ + if (tdb1_unlock_record(tdb, tdb->travlocks.off) != 0) + return tdb1_null; + tdb->travlocks.off = tdb->travlocks.hash = 0; + tdb->travlocks.lock_rw = F_RDLCK; + + /* Grab first record: locks chain and returned record. */ + off = tdb1_next_lock(tdb, &tdb->travlocks, &rec); + if (off == 0 || off == TDB1_NEXT_LOCK_ERR) { + return tdb1_null; + } + /* now read the key */ + key.dsize = rec.key_len; + key.dptr =tdb1_alloc_read(tdb,tdb->travlocks.off+sizeof(rec),key.dsize); + + /* Unlock the hash chain of the record we just read. */ + if (tdb1_unlock(tdb, tdb->travlocks.hash, tdb->travlocks.lock_rw) != 0) + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "tdb1_firstkey: error occurred while tdb1_unlocking!\n")); + return key; +} + +/* find the next entry in the database, returning its key */ +_PUBLIC_ TDB1_DATA tdb1_nextkey(struct tdb1_context *tdb, TDB1_DATA oldkey) +{ + uint32_t oldhash; + TDB1_DATA key = tdb1_null; + struct tdb1_record rec; + unsigned char *k = NULL; + tdb1_off_t off; + + /* Is locked key the old key? If so, traverse will be reliable. */ + if (tdb->travlocks.off) { + if (tdb1_lock(tdb,tdb->travlocks.hash,tdb->travlocks.lock_rw)) + return tdb1_null; + if (tdb1_rec_read(tdb, tdb->travlocks.off, &rec) == -1 + || !(k = tdb1_alloc_read(tdb,tdb->travlocks.off+sizeof(rec), + rec.key_len)) + || memcmp(k, oldkey.dptr, oldkey.dsize) != 0) { + /* No, it wasn't: unlock it and start from scratch */ + if (tdb1_unlock_record(tdb, tdb->travlocks.off) != 0) { + SAFE_FREE(k); + return tdb1_null; + } + if (tdb1_unlock(tdb, tdb->travlocks.hash, tdb->travlocks.lock_rw) != 0) { + SAFE_FREE(k); + return tdb1_null; + } + tdb->travlocks.off = 0; + } + + SAFE_FREE(k); + } + + if (!tdb->travlocks.off) { + /* No previous element: do normal find, and lock record */ + tdb->travlocks.off = tdb1_find_lock_hash(tdb, oldkey, tdb->hash_fn(&oldkey), tdb->travlocks.lock_rw, &rec); + if (!tdb->travlocks.off) { + return tdb1_null; + } + tdb->travlocks.hash = TDB1_BUCKET(rec.full_hash); + if (tdb1_lock_record(tdb, tdb->travlocks.off) != 0) { + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "tdb1_nextkey: lock_record failed (%s)!\n", strerror(errno))); + return tdb1_null; + } + } + oldhash = tdb->travlocks.hash; + + /* Grab next record: locks chain and returned record, + unlocks old record */ + off = tdb1_next_lock(tdb, &tdb->travlocks, &rec); + if (off != TDB1_NEXT_LOCK_ERR && off != 0) { + key.dsize = rec.key_len; + key.dptr = tdb1_alloc_read(tdb, tdb->travlocks.off+sizeof(rec), + key.dsize); + /* Unlock the chain of this new record */ + if (tdb1_unlock(tdb, tdb->travlocks.hash, tdb->travlocks.lock_rw) != 0) + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "tdb1_nextkey: WARNING tdb1_unlock failed!\n")); + } + /* Unlock the chain of old record */ + if (tdb1_unlock(tdb, TDB1_BUCKET(oldhash), tdb->travlocks.lock_rw) != 0) + TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "tdb1_nextkey: WARNING tdb1_unlock failed!\n")); + return key; +}