+++ /dev/null
- /*
- 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 <http://www.gnu.org/licenses/>.
-*/
-
-#include "tdb_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 tdb_oob(struct tdb_context *tdb, tdb_off_t len, int probe)
-{
- struct stat st;
- if (len <= tdb->map_size)
- return 0;
- if (tdb->flags & TDB_INTERNAL) {
- if (!probe) {
- /* Ensure ecode is set for log fn. */
- tdb->ecode = TDB_ERR_IO;
- TDB_LOG((tdb, TDB_DEBUG_FATAL,"tdb_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 = TDB_ERR_IO;
- return -1;
- }
-
- if (st.st_size < (size_t)len) {
- if (!probe) {
- /* Ensure ecode is set for log fn. */
- tdb->ecode = TDB_ERR_IO;
- TDB_LOG((tdb, TDB_DEBUG_FATAL,"tdb_oob len %d beyond eof at %d\n",
- (int)len, (int)st.st_size));
- }
- return -1;
- }
-
- /* Unmap, update size, remap */
- if (tdb_munmap(tdb) == -1) {
- tdb->ecode = TDB_ERR_IO;
- return -1;
- }
- tdb->map_size = st.st_size;
- tdb_mmap(tdb);
- return 0;
-}
-
-/* write a lump of data at a specified offset */
-static int tdb_write(struct tdb_context *tdb, tdb_off_t off,
- const void *buf, tdb_len_t len)
-{
- if (len == 0) {
- return 0;
- }
-
- if (tdb->read_only || tdb->traverse_read) {
- tdb->ecode = TDB_ERR_RDONLY;
- return -1;
- }
-
- if (tdb->methods->tdb_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 = TDB_ERR_IO;
- TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_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 = TDB_ERR_IO;
- TDB_LOG((tdb, TDB_DEBUG_FATAL,"tdb_write failed at %d "
- "len=%d (%s)\n", off, len, strerror(errno)));
- return -1;
- } else if (written != (ssize_t)len) {
- tdb->ecode = TDB_ERR_IO;
- TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_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 *tdb_convert(void *buf, uint32_t size)
-{
- uint32_t i;
- unsigned char *p = buf, tmp;
-
- for (i = 0; i < size; i += 4) {
- tmp = p[i];
- p[i] = p[i+3];
- p[i+3] = tmp;
- tmp = p[i+1];
- p[i+1] = p[i+2];
- p[i+2] = tmp;
- }
- return buf;
-}
-
-
-/* read a lump of data at a specified offset, maybe convert */
-static int tdb_read(struct tdb_context *tdb, tdb_off_t off, void *buf,
- tdb_len_t len, int cv)
-{
- if (tdb->methods->tdb_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 = TDB_ERR_IO;
- TDB_LOG((tdb, TDB_DEBUG_FATAL,"tdb_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) {
- tdb_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 tdb_next_hash_chain(struct tdb_context *tdb, uint32_t *chain)
-{
- uint32_t h = *chain;
- if (tdb->map_ptr) {
- for (;h < tdb->header.hash_size;h++) {
- if (0 != *(uint32_t *)(TDB_HASH_TOP(h) + (unsigned char *)tdb->map_ptr)) {
- break;
- }
- }
- } else {
- uint32_t off=0;
- for (;h < tdb->header.hash_size;h++) {
- if (tdb_ofs_read(tdb, TDB_HASH_TOP(h), &off) != 0 || off != 0) {
- break;
- }
- }
- }
- (*chain) = h;
-}
-
-
-int tdb_munmap(struct tdb_context *tdb)
-{
- if (tdb->flags & TDB_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 tdb_mmap(struct tdb_context *tdb)
-{
- if (tdb->flags & TDB_INTERNAL)
- return;
-
-#if HAVE_MMAP
- if (!(tdb->flags & TDB_NOMMAP)) {
- tdb->map_ptr = mmap(NULL, tdb->map_size,
- PROT_READ|(tdb->read_only? 0:PROT_WRITE),
- MAP_SHARED, tdb->fd, 0);
-
- /*
- * NB. When mmap fails it returns MAP_FAILED *NOT* NULL !!!!
- */
-
- if (tdb->map_ptr == MAP_FAILED) {
- tdb->map_ptr = NULL;
- TDB_LOG((tdb, TDB_DEBUG_WARNING, "tdb_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 tdb_expand_file(struct tdb_context *tdb, tdb_off_t size, tdb_off_t addition)
-{
- char buf[8192];
-
- if (tdb->read_only || tdb->traverse_read) {
- tdb->ecode = TDB_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) {
- TDB_LOG((tdb, TDB_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, TDB_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 */
- TDB_LOG((tdb, TDB_DEBUG_FATAL, "expand_file write "
- "returned 0 twice: giving up!\n"));
- errno = ENOSPC;
- return -1;
- } else if (written == -1) {
- TDB_LOG((tdb, TDB_DEBUG_FATAL, "expand_file write of "
- "%d bytes failed (%s)\n", (int)n,
- strerror(errno)));
- return -1;
- } else if (written != n) {
- TDB_LOG((tdb, TDB_DEBUG_WARNING, "expand_file: wrote "
- "only %d of %d bytes - retrying\n", (int)written,
- (int)n));
- }
- addition -= written;
- size += written;
- }
- return 0;
-}
-
-/* You need 'size', this tells you how much you should expand by. */
-tdb_off_t tdb_expand_adjust(tdb_off_t map_size, tdb_off_t size, int page_size)
-{
- tdb_off_t new_size, top_size;
-
- /* 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 = map_size + size * 2;
- } else {
- top_size = 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 (map_size > 100 * 1024 * 1024) {
- new_size = map_size * 1.10;
- } else {
- new_size = map_size * 1.25;
- }
-
- /* Round the database up to a multiple of the page size */
- new_size = MAX(top_size, new_size);
- return TDB_ALIGN(new_size, page_size) - map_size;
-}
-
-/* expand the database at least size bytes by expanding the underlying
- file and doing the mmap again if necessary */
-int tdb_expand(struct tdb_context *tdb, tdb_off_t size)
-{
- struct tdb_record rec;
- tdb_off_t offset;
-
- if (tdb_lock(tdb, -1, F_WRLCK) == -1) {
- TDB_LOG((tdb, TDB_DEBUG_ERROR, "lock failed in tdb_expand\n"));
- return -1;
- }
-
- /* must know about any previous expansions by another process */
- tdb->methods->tdb_oob(tdb, tdb->map_size + 1, 1);
-
- size = tdb_expand_adjust(tdb->map_size, size, tdb->page_size);
-
- if (!(tdb->flags & TDB_INTERNAL))
- tdb_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 & TDB_INTERNAL)) {
- if (tdb->methods->tdb_expand_file(tdb, tdb->map_size, size) != 0)
- goto fail;
- }
-
- tdb->map_size += size;
-
- if (tdb->flags & TDB_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 */
- tdb_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 (tdb_free(tdb, offset, &rec) == -1)
- goto fail;
-
- tdb_unlock(tdb, -1, F_WRLCK);
- return 0;
- fail:
- tdb_unlock(tdb, -1, F_WRLCK);
- return -1;
-}
-
-/* read/write a tdb_off_t */
-int tdb_ofs_read(struct tdb_context *tdb, tdb_off_t offset, tdb_off_t *d)
-{
- return tdb->methods->tdb_read(tdb, offset, (char*)d, sizeof(*d), DOCONV());
-}
-
-int tdb_ofs_write(struct tdb_context *tdb, tdb_off_t offset, tdb_off_t *d)
-{
- tdb_off_t off = *d;
- return tdb->methods->tdb_write(tdb, offset, CONVERT(off), sizeof(*d));
-}
-
-
-/* read a lump of data, allocating the space for it */
-unsigned char *tdb_alloc_read(struct tdb_context *tdb, tdb_off_t offset, tdb_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 = TDB_ERR_OOM;
- TDB_LOG((tdb, TDB_DEBUG_ERROR,"tdb_alloc_read malloc failed len=%d (%s)\n",
- len, strerror(errno)));
- return NULL;
- }
- if (tdb->methods->tdb_read(tdb, offset, buf, len, 0) == -1) {
- SAFE_FREE(buf);
- return NULL;
- }
- return buf;
-}
-
-/* Give a piece of tdb data to a parser */
-
-int tdb_parse_data(struct tdb_context *tdb, TDB_DATA key,
- tdb_off_t offset, tdb_len_t len,
- int (*parser)(TDB_DATA key, TDB_DATA data,
- void *private_data),
- void *private_data)
-{
- TDB_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->tdb_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 = tdb_alloc_read(tdb, offset, len))) {
- return -1;
- }
-
- result = parser(key, data, private_data);
- free(data.dptr);
- return result;
-}
-
-/* read/write a record */
-int tdb_rec_read(struct tdb_context *tdb, tdb_off_t offset, struct tdb_record *rec)
-{
- if (tdb->methods->tdb_read(tdb, offset, rec, sizeof(*rec),DOCONV()) == -1)
- return -1;
- if (TDB_BAD_MAGIC(rec)) {
- /* Ensure ecode is set for log fn. */
- tdb->ecode = TDB_ERR_CORRUPT;
- TDB_LOG((tdb, TDB_DEBUG_FATAL,"tdb_rec_read bad magic 0x%x at offset=%d\n", rec->magic, offset));
- return -1;
- }
- return tdb->methods->tdb_oob(tdb, rec->next+sizeof(*rec), 0);
-}
-
-int tdb_rec_write(struct tdb_context *tdb, tdb_off_t offset, struct tdb_record *rec)
-{
- struct tdb_record r = *rec;
- return tdb->methods->tdb_write(tdb, offset, CONVERT(r), sizeof(r));
-}
-
-static const struct tdb_methods io_methods = {
- tdb_read,
- tdb_write,
- tdb_next_hash_chain,
- tdb_oob,
- tdb_expand_file,
-};
-
-/*
- initialise the default methods table
-*/
-void tdb_io_init(struct tdb_context *tdb)
-{
- tdb->methods = &io_methods;
-}
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