X-Git-Url: https://git.ozlabs.org/?p=ccan;a=blobdiff_plain;f=ccan%2Ftdb2%2Ftdb2.h;fp=ccan%2Ftdb2%2Ftdb2.h;h=0000000000000000000000000000000000000000;hp=3fa99b15dbb6cab3d09162b3789efd5b8501e875;hb=b91dafc6ab5075355d508f051977a15dd7794b0e;hpb=0b93bd102aad6b61f1e569fb12aabc6352a1d7cd diff --git a/ccan/tdb2/tdb2.h b/ccan/tdb2/tdb2.h deleted file mode 100644 index 3fa99b15..00000000 --- a/ccan/tdb2/tdb2.h +++ /dev/null @@ -1,924 +0,0 @@ -#ifndef CCAN_TDB2_H -#define CCAN_TDB2_H - -/* - TDB version 2: trivial database library - - Copyright (C) Andrew Tridgell 1999-2004 - Copyright (C) Rusty Russell 2010-2011 - - ** 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 . -*/ - -#ifdef __cplusplus -extern "C" { -#endif - -#ifndef _SAMBA_BUILD_ -#include "config.h" -#if HAVE_FILE_OFFSET_BITS -#define _FILE_OFFSET_BITS 64 -#endif -/* For mode_t */ -#include -/* For O_* flags. */ -#include -/* For sig_atomic_t. */ -#include -/* For uint64_t */ -#include -/* For bool */ -#include -/* For memcmp */ -#include -#endif -#include -#include -#include - -union tdb_attribute; -struct tdb_context; - -/** - * tdb_open - open a database file - * @name: the file name (can be NULL if flags contains TDB_INTERNAL) - * @tdb_flags: options for this database - * @open_flags: flags argument for tdb's open() call. - * @mode: mode argument for tdb's open() call. - * @attributes: linked list of extra attributes for this tdb. - * - * This call opens (and potentially creates) a database file. - * Multiple processes can have the TDB file open at once. - * - * On failure it will return NULL, and set errno: it may also call - * any log attribute found in @attributes. - * - * See also: - * union tdb_attribute - */ -struct tdb_context *tdb_open(const char *name, int tdb_flags, - int open_flags, mode_t mode, - union tdb_attribute *attributes); - - -/* flags for tdb_open() */ -#define TDB_DEFAULT 0 /* just a readability place holder */ -#define TDB_INTERNAL 2 /* don't store on disk */ -#define TDB_NOLOCK 4 /* don't do any locking */ -#define TDB_NOMMAP 8 /* don't use mmap */ -#define TDB_CONVERT 16 /* convert endian */ -#define TDB_NOSYNC 64 /* don't use synchronous transactions */ -#define TDB_SEQNUM 128 /* maintain a sequence number */ -#define TDB_ALLOW_NESTING 256 /* fake nested transactions */ -#define TDB_RDONLY 512 /* implied by O_RDONLY */ -#define TDB_VERSION1 1024 /* create/open an old style TDB */ -#define TDB_CANT_CHECK 2048 /* has a feature which we don't understand */ - -/** - * tdb1_incompatible_hash - better (Jenkins) hash for tdb1 - * - * This is better than the default hash for tdb1; but older versions of the - * tdb library (prior to version 1.2.6) won't be able to open them. - * - * It only makes sense to specify this (using tdb_attribute_hash) when - * creating (with O_CREAT) an old tdb version using TDB_VERSION1. It's - * equivalent to the TDB_INCOMPATIBLE_HASH flag for tdb1. - */ -uint64_t tdb1_incompatible_hash(const void *, size_t, uint64_t, void *); - -/** - * tdb_close - close and free a tdb. - * @tdb: the tdb context returned from tdb_open() - * - * This always succeeds, in that @tdb is unusable after this call. But if - * some unexpected error occurred while closing, it will return non-zero - * (the only clue as to cause will be via the log attribute). - */ -int tdb_close(struct tdb_context *tdb); - -/** - * struct tdb_data - representation of keys or values. - * @dptr: the data pointer - * @dsize: the size of the data pointed to by dptr. - * - * This is the "blob" representation of keys and data used by TDB. - */ -typedef struct tdb_data { - unsigned char *dptr; - size_t dsize; -} TDB_DATA; - -/** - * enum TDB_ERROR - error returns for TDB - * - * See Also: - * tdb_errorstr() - */ -enum TDB_ERROR { - TDB_SUCCESS = 0, /* No error. */ - TDB_ERR_CORRUPT = -1, /* We read the db, and it was bogus. */ - TDB_ERR_IO = -2, /* We couldn't read/write the db. */ - TDB_ERR_LOCK = -3, /* Locking failed. */ - TDB_ERR_OOM = -4, /* Out of Memory. */ - TDB_ERR_EXISTS = -5, /* The key already exists. */ - TDB_ERR_NOEXIST = -6, /* The key does not exist. */ - TDB_ERR_EINVAL = -7, /* You're using it wrong. */ - TDB_ERR_RDONLY = -8, /* The database is read-only. */ - TDB_ERR_LAST = TDB_ERR_RDONLY -}; - -/** - * tdb_store - store a key/value pair in a tdb. - * @tdb: the tdb context returned from tdb_open() - * @key: the key - * @dbuf: the data to associate with the key. - * @flag: TDB_REPLACE, TDB_INSERT or TDB_MODIFY. - * - * This inserts (or overwrites) a key/value pair in the TDB. If flag - * is TDB_REPLACE, it doesn't matter whether the key exists or not; - * TDB_INSERT means it must not exist (returns TDB_ERR_EXISTS otherwise), - * and TDB_MODIFY means it must exist (returns TDB_ERR_NOEXIST otherwise). - * - * On success, this returns TDB_SUCCESS. - * - * See also: - * tdb_fetch, tdb_transaction_start, tdb_append, tdb_delete. - */ -enum TDB_ERROR tdb_store(struct tdb_context *tdb, - struct tdb_data key, - struct tdb_data dbuf, - int flag); - -/* flags to tdb_store() */ -#define TDB_REPLACE 1 /* A readability place holder */ -#define TDB_INSERT 2 /* Don't overwrite an existing entry */ -#define TDB_MODIFY 3 /* Don't create an existing entry */ - -/** - * tdb_fetch - fetch a value from a tdb. - * @tdb: the tdb context returned from tdb_open() - * @key: the key - * @data: pointer to data. - * - * This looks up a key in the database and sets it in @data. - * - * If it returns TDB_SUCCESS, the key was found: it is your - * responsibility to call free() on @data->dptr. - * - * Otherwise, it returns an error (usually, TDB_ERR_NOEXIST) and @data is - * undefined. - */ -enum TDB_ERROR tdb_fetch(struct tdb_context *tdb, struct tdb_data key, - struct tdb_data *data); - -/** - * tdb_errorstr - map the tdb error onto a constant readable string - * @ecode: the enum TDB_ERROR to map. - * - * This is useful for displaying errors to users. - */ -const char *tdb_errorstr(enum TDB_ERROR ecode); - -/** - * tdb_append - append a value to a key/value pair in a tdb. - * @tdb: the tdb context returned from tdb_open() - * @key: the key - * @dbuf: the data to append. - * - * This is equivalent to fetching a record, reallocating .dptr to add the - * data, and writing it back, only it's much more efficient. If the key - * doesn't exist, it's equivalent to tdb_store (with an additional hint that - * you expect to expand the record in future). - * - * See Also: - * tdb_fetch(), tdb_store() - */ -enum TDB_ERROR tdb_append(struct tdb_context *tdb, - struct tdb_data key, struct tdb_data dbuf); - -/** - * tdb_delete - delete a key from a tdb. - * @tdb: the tdb context returned from tdb_open() - * @key: the key to delete. - * - * Returns TDB_SUCCESS on success, or an error (usually TDB_ERR_NOEXIST). - * - * See Also: - * tdb_fetch(), tdb_store() - */ -enum TDB_ERROR tdb_delete(struct tdb_context *tdb, struct tdb_data key); - -/** - * tdb_exists - does a key exist in the database? - * @tdb: the tdb context returned from tdb_open() - * @key: the key to search for. - * - * Returns true if it exists, or false if it doesn't or any other error. - */ -bool tdb_exists(struct tdb_context *tdb, TDB_DATA key); - -/** - * tdb_deq - are struct tdb_data equal? - * @a: one struct tdb_data - * @b: another struct tdb_data - */ -static inline bool tdb_deq(struct tdb_data a, struct tdb_data b) -{ - return a.dsize == b.dsize && memcmp(a.dptr, b.dptr, a.dsize) == 0; -} - -/** - * tdb_mkdata - make a struct tdb_data from const data - * @p: the constant pointer - * @len: the length - * - * As the dptr member of struct tdb_data is not constant, you need to - * cast it. This function keeps thost casts in one place, as well as - * suppressing the warning some compilers give when casting away a - * qualifier (eg. gcc with -Wcast-qual) - */ -static inline struct tdb_data tdb_mkdata(const void *p, size_t len) -{ - struct tdb_data d; - d.dptr = cast_const(void *, p); - d.dsize = len; - return d; -} - -/** - * tdb_transaction_start - start a transaction - * @tdb: the tdb context returned from tdb_open() - * - * This begins a series of atomic operations. Other processes will be able - * to read the tdb, but not alter it (they will block), nor will they see - * any changes until tdb_transaction_commit() is called. - * - * Note that if the TDB_ALLOW_NESTING flag is set, a tdb_transaction_start() - * within a transaction will succeed, but it's not a real transaction: - * (1) An inner transaction which is committed is not actually committed until - * the outer transaction is; if the outer transaction is cancelled, the - * inner ones are discarded. - * (2) tdb_transaction_cancel() marks the outer transaction as having an error, - * so the final tdb_transaction_commit() will fail. - * (3) the outer transaction will see the results of the inner transaction. - * - * See Also: - * tdb_transaction_cancel, tdb_transaction_commit. - */ -enum TDB_ERROR tdb_transaction_start(struct tdb_context *tdb); - -/** - * tdb_transaction_cancel - abandon a transaction - * @tdb: the tdb context returned from tdb_open() - * - * This aborts a transaction, discarding any changes which were made. - * tdb_close() does this implicitly. - */ -void tdb_transaction_cancel(struct tdb_context *tdb); - -/** - * tdb_transaction_commit - commit a transaction - * @tdb: the tdb context returned from tdb_open() - * - * This completes a transaction, writing any changes which were made. - * - * fsync() is used to commit the transaction (unless TDB_NOSYNC is set), - * making it robust against machine crashes, but very slow compared to - * other TDB operations. - * - * A failure can only be caused by unexpected errors (eg. I/O or - * memory); this is no point looping on transaction failure. - * - * See Also: - * tdb_transaction_prepare_commit() - */ -enum TDB_ERROR tdb_transaction_commit(struct tdb_context *tdb); - -/** - * tdb_transaction_prepare_commit - prepare to commit a transaction - * @tdb: the tdb context returned from tdb_open() - * - * This ensures we have the resources to commit a transaction (using - * tdb_transaction_commit): if this succeeds then a transaction will only - * fail if the write() or fsync() calls fail. - * - * If this fails you must still call tdb_transaction_cancel() to cancel - * the transaction. - * - * See Also: - * tdb_transaction_commit() - */ -enum TDB_ERROR tdb_transaction_prepare_commit(struct tdb_context *tdb); - -/** - * tdb_traverse - traverse a TDB - * @tdb: the tdb context returned from tdb_open() - * @fn: the function to call for every key/value pair (or NULL) - * @p: the pointer to hand to @f - * - * This walks the TDB until all they keys have been traversed, or @fn - * returns non-zero. If the traverse function or other processes are - * changing data or adding or deleting keys, the traverse may be - * unreliable: keys may be skipped or (rarely) visited twice. - * - * There is one specific exception: the special case of deleting the - * current key does not undermine the reliability of the traversal. - * - * On success, returns the number of keys iterated. On error returns - * a negative enum TDB_ERROR value. - */ -#define tdb_traverse(tdb, fn, p) \ - tdb_traverse_(tdb, typesafe_cb_preargs(int, void *, (fn), (p), \ - struct tdb_context *, \ - TDB_DATA, TDB_DATA), (p)) - -int64_t tdb_traverse_(struct tdb_context *tdb, - int (*fn)(struct tdb_context *, - TDB_DATA, TDB_DATA, void *), void *p); - -/** - * tdb_parse_record - operate directly on data in the database. - * @tdb: the tdb context returned from tdb_open() - * @key: the key whose record we should hand to @parse - * @parse: the function to call for the data - * @data: the private pointer to hand to @parse (types must match). - * - * This avoids a copy for many cases, by handing you a pointer into - * the memory-mapped database. It also locks the record to prevent - * other accesses at the same time. - * - * Do not alter the data handed to parse()! - */ -#define tdb_parse_record(tdb, key, parse, data) \ - tdb_parse_record_((tdb), (key), \ - typesafe_cb_preargs(enum TDB_ERROR, void *, \ - (parse), (data), \ - TDB_DATA, TDB_DATA), (data)) - -enum TDB_ERROR tdb_parse_record_(struct tdb_context *tdb, - TDB_DATA key, - enum TDB_ERROR (*parse)(TDB_DATA k, - TDB_DATA d, - void *data), - void *data); - -/** - * tdb_get_seqnum - get a database sequence number - * @tdb: the tdb context returned from tdb_open() - * - * This returns a sequence number: any change to the database from a - * tdb context opened with the TDB_SEQNUM flag will cause that number - * to increment. Note that the incrementing is unreliable (it is done - * without locking), so this is only useful as an optimization. - * - * For example, you may have a regular database backup routine which - * does not operate if the sequence number is unchanged. In the - * unlikely event of a failed increment, it will be backed up next - * time any way. - * - * Returns an enum TDB_ERROR (ie. negative) on error. - */ -int64_t tdb_get_seqnum(struct tdb_context *tdb); - -/** - * tdb_firstkey - get the "first" key in a TDB - * @tdb: the tdb context returned from tdb_open() - * @key: pointer to key. - * - * This returns an arbitrary key in the database; with tdb_nextkey() it allows - * open-coded traversal of the database, though it is slightly less efficient - * than tdb_traverse. - * - * It is your responsibility to free @key->dptr on success. - * - * Returns TDB_ERR_NOEXIST if the database is empty. - */ -enum TDB_ERROR tdb_firstkey(struct tdb_context *tdb, struct tdb_data *key); - -/** - * tdb_nextkey - get the "next" key in a TDB - * @tdb: the tdb context returned from tdb_open() - * @key: a key returned by tdb_firstkey() or tdb_nextkey(). - * - * This returns another key in the database; it will free @key.dptr for - * your convenience. - * - * Returns TDB_ERR_NOEXIST if there are no more keys. - */ -enum TDB_ERROR tdb_nextkey(struct tdb_context *tdb, struct tdb_data *key); - -/** - * tdb_chainlock - lock a record in the TDB - * @tdb: the tdb context returned from tdb_open() - * @key: the key to lock. - * - * This prevents any access occurring to a group of keys including @key, - * even if @key does not exist. This allows primitive atomic updates of - * records without using transactions. - * - * You cannot begin a transaction while holding a tdb_chainlock(), nor can - * you do any operations on any other keys in the database. This also means - * that you cannot hold more than one tdb_chainlock() at a time. - * - * See Also: - * tdb_chainunlock() - */ -enum TDB_ERROR tdb_chainlock(struct tdb_context *tdb, TDB_DATA key); - -/** - * tdb_chainunlock - unlock a record in the TDB - * @tdb: the tdb context returned from tdb_open() - * @key: the key to unlock. - * - * The key must have previously been locked by tdb_chainlock(). - */ -void tdb_chainunlock(struct tdb_context *tdb, TDB_DATA key); - -/** - * tdb_chainlock_read - lock a record in the TDB, for reading - * @tdb: the tdb context returned from tdb_open() - * @key: the key to lock. - * - * This prevents any changes from occurring to a group of keys including @key, - * even if @key does not exist. This allows primitive atomic updates of - * records without using transactions. - * - * You cannot begin a transaction while holding a tdb_chainlock_read(), nor can - * you do any operations on any other keys in the database. This also means - * that you cannot hold more than one tdb_chainlock()/read() at a time. - * - * See Also: - * tdb_chainlock() - */ -enum TDB_ERROR tdb_chainlock_read(struct tdb_context *tdb, TDB_DATA key); - -/** - * tdb_chainunlock_read - unlock a record in the TDB for reading - * @tdb: the tdb context returned from tdb_open() - * @key: the key to unlock. - * - * The key must have previously been locked by tdb_chainlock_read(). - */ -void tdb_chainunlock_read(struct tdb_context *tdb, TDB_DATA key); - -/** - * tdb_lockall - lock the entire TDB - * @tdb: the tdb context returned from tdb_open() - * - * You cannot hold a tdb_chainlock while calling this. It nests, so you - * must call tdb_unlockall as many times as you call tdb_lockall. - */ -enum TDB_ERROR tdb_lockall(struct tdb_context *tdb); - -/** - * tdb_unlockall - unlock the entire TDB - * @tdb: the tdb context returned from tdb_open() - */ -void tdb_unlockall(struct tdb_context *tdb); - -/** - * tdb_lockall_read - lock the entire TDB for reading - * @tdb: the tdb context returned from tdb_open() - * - * This prevents others writing to the database, eg. tdb_delete, tdb_store, - * tdb_append, but not tdb_fetch. - * - * You cannot hold a tdb_chainlock while calling this. It nests, so you - * must call tdb_unlockall_read as many times as you call tdb_lockall_read. - */ -enum TDB_ERROR tdb_lockall_read(struct tdb_context *tdb); - -/** - * tdb_unlockall_read - unlock the entire TDB for reading - * @tdb: the tdb context returned from tdb_open() - */ -void tdb_unlockall_read(struct tdb_context *tdb); - -/** - * tdb_wipe_all - wipe the database clean - * @tdb: the tdb context returned from tdb_open() - * - * Completely erase the database. This is faster than iterating through - * each key and doing tdb_delete. - */ -enum TDB_ERROR tdb_wipe_all(struct tdb_context *tdb); - -/** - * tdb_repack - repack the database - * @tdb: the tdb context returned from tdb_open() - * - * This repacks the database; if it is suffering from a great deal of - * fragmentation this might help. However, it can take twice the - * memory of the existing TDB. - */ -enum TDB_ERROR tdb_repack(struct tdb_context *tdb); - -/** - * tdb_check - check a TDB for consistency - * @tdb: the tdb context returned from tdb_open() - * @check: function to check each key/data pair (or NULL) - * @data: argument for @check, must match type. - * - * This performs a consistency check of the open database, optionally calling - * a check() function on each record so you can do your own data consistency - * checks as well. If check() returns an error, that is returned from - * tdb_check(). - * - * Note that the TDB uses a feature which we don't understand which - * indicates we can't run tdb_check(), this will log a warning to that - * effect and return TDB_SUCCESS. You can detect this condition by - * looking for TDB_CANT_CHECK in tdb_get_flags(). - * - * Returns TDB_SUCCESS or an error. - */ -#define tdb_check(tdb, check, data) \ - tdb_check_((tdb), typesafe_cb_preargs(enum TDB_ERROR, void *, \ - (check), (data), \ - struct tdb_data, \ - struct tdb_data), \ - (data)) - -enum TDB_ERROR tdb_check_(struct tdb_context *tdb, - enum TDB_ERROR (*check)(struct tdb_data k, - struct tdb_data d, - void *data), - void *data); - -/** - * tdb_error - get the last error (not threadsafe) - * @tdb: the tdb context returned from tdb_open() - * - * Returns the last error returned by a TDB function. - * - * This makes porting from TDB1 easier, but note that the last error is not - * reliable in threaded programs. - */ -enum TDB_ERROR tdb_error(struct tdb_context *tdb); - -/** - * enum tdb_summary_flags - flags for tdb_summary. - */ -enum tdb_summary_flags { - TDB_SUMMARY_HISTOGRAMS = 1 /* Draw graphs in the summary. */ -}; - -/** - * tdb_summary - return a string describing the TDB state - * @tdb: the tdb context returned from tdb_open() - * @flags: flags to control the summary output. - * @summary: pointer to string to allocate. - * - * This returns a developer-readable string describing the overall - * state of the tdb, such as the percentage used and sizes of records. - * It is designed to provide information about the tdb at a glance - * without displaying any keys or data in the database. - * - * On success, sets @summary to point to a malloc()'ed nul-terminated - * multi-line string. It is your responsibility to free() it. - */ -enum TDB_ERROR tdb_summary(struct tdb_context *tdb, - enum tdb_summary_flags flags, - char **summary); - - -/** - * tdb_get_flags - return the flags for a tdb - * @tdb: the tdb context returned from tdb_open() - * - * This returns the flags on the current tdb. Some of these are caused by - * the flags argument to tdb_open(), others (such as TDB_CONVERT) are - * intuited. - */ -unsigned int tdb_get_flags(struct tdb_context *tdb); - -/** - * tdb_add_flag - set a flag for a tdb - * @tdb: the tdb context returned from tdb_open() - * @flag: one of TDB_NOLOCK, TDB_NOMMAP, TDB_NOSYNC or TDB_ALLOW_NESTING. - * - * You can use this to set a flag on the TDB. You cannot set these flags - * on a TDB_INTERNAL tdb. - */ -void tdb_add_flag(struct tdb_context *tdb, unsigned flag); - -/** - * tdb_remove_flag - unset a flag for a tdb - * @tdb: the tdb context returned from tdb_open() - * @flag: one of TDB_NOLOCK, TDB_NOMMAP, TDB_NOSYNC or TDB_ALLOW_NESTING. - * - * You can use this to clear a flag on the TDB. You cannot clear flags - * on a TDB_INTERNAL tdb. - */ -void tdb_remove_flag(struct tdb_context *tdb, unsigned flag); - -/** - * enum tdb_attribute_type - descriminator for union tdb_attribute. - */ -enum tdb_attribute_type { - TDB_ATTRIBUTE_LOG = 0, - TDB_ATTRIBUTE_HASH = 1, - TDB_ATTRIBUTE_SEED = 2, - TDB_ATTRIBUTE_STATS = 3, - TDB_ATTRIBUTE_OPENHOOK = 4, - TDB_ATTRIBUTE_FLOCK = 5, - TDB_ATTRIBUTE_TDB1_HASHSIZE = 128, - TDB_ATTRIBUTE_TDB1_MAX_DEAD = 129, -}; - -/** - * tdb_get_attribute - get an attribute for an existing tdb - * @tdb: the tdb context returned from tdb_open() - * @attr: the union tdb_attribute to set. - * - * This gets an attribute from a TDB which has previously been set (or - * may return the default values). Set @attr.base.attr to the - * attribute type you want get. - */ -enum TDB_ERROR tdb_get_attribute(struct tdb_context *tdb, - union tdb_attribute *attr); - -/** - * tdb_set_attribute - set an attribute for an existing tdb - * @tdb: the tdb context returned from tdb_open() - * @attr: the union tdb_attribute to set. - * - * This sets an attribute on a TDB, overriding any previous attribute - * of the same type. It returns TDB_ERR_EINVAL if the attribute is - * unknown or invalid. - * - * Note that TDB_ATTRIBUTE_HASH, TDB_ATTRIBUTE_SEED, - * TDB_ATTRIBUTE_OPENHOOK and TDB_ATTRIBUTE_TDB1_HASHSIZE cannot - * currently be set after tdb_open. - */ -enum TDB_ERROR tdb_set_attribute(struct tdb_context *tdb, - const union tdb_attribute *attr); - -/** - * tdb_unset_attribute - reset an attribute for an existing tdb - * @tdb: the tdb context returned from tdb_open() - * @type: the attribute type to unset. - * - * This unsets an attribute on a TDB, returning it to the defaults - * (where applicable). - * - * Note that it only makes sense for TDB_ATTRIBUTE_LOG and TDB_ATTRIBUTE_FLOCK - * to be unset. - */ -void tdb_unset_attribute(struct tdb_context *tdb, - enum tdb_attribute_type type); - -/** - * tdb_name - get the name of a tdb - * @tdb: the tdb context returned from tdb_open() - * - * This returns a copy of the name string, made at tdb_open() time. If that - * argument was NULL (possible for a TDB_INTERNAL db) this will return NULL. - * - * This is mostly useful for logging. - */ -const char *tdb_name(const struct tdb_context *tdb); - -/** - * tdb_fd - get the file descriptor of a tdb - * @tdb: the tdb context returned from tdb_open() - * - * This returns the file descriptor for the underlying database file, or -1 - * for TDB_INTERNAL. - */ -int tdb_fd(const struct tdb_context *tdb); - -/** - * tdb_foreach - iterate through every open TDB. - * @fn: the function to call for every TDB - * @p: the pointer to hand to @fn - * - * TDB internally keeps track of all open TDBs; this function allows you to - * iterate through them. If @fn returns non-zero, traversal stops. - */ -#define tdb_foreach(fn, p) \ - tdb_foreach_(typesafe_cb_preargs(int, void *, (fn), (p), \ - struct tdb_context *), (p)) - -void tdb_foreach_(int (*fn)(struct tdb_context *, void *), void *p); - -/** - * struct tdb_attribute_base - common fields for all tdb attributes. - */ -struct tdb_attribute_base { - enum tdb_attribute_type attr; - union tdb_attribute *next; -}; - -/** - * enum tdb_log_level - log levels for tdb_attribute_log - * @TDB_LOG_ERROR: used to log unrecoverable errors such as I/O errors - * or internal consistency failures. - * @TDB_LOG_USE_ERROR: used to log usage errors such as invalid parameters - * or writing to a read-only database. - * @TDB_LOG_WARNING: used for informational messages on issues which - * are unusual but handled by TDB internally, such - * as a failure to mmap or failure to open /dev/urandom. - */ -enum tdb_log_level { - TDB_LOG_ERROR, - TDB_LOG_USE_ERROR, - TDB_LOG_WARNING -}; - -/** - * struct tdb_attribute_log - log function attribute - * - * This attribute provides a hook for you to log errors. - */ -struct tdb_attribute_log { - struct tdb_attribute_base base; /* .attr = TDB_ATTRIBUTE_LOG */ - void (*fn)(struct tdb_context *tdb, - enum tdb_log_level level, - enum TDB_ERROR ecode, - const char *message, - void *data); - void *data; -}; - -/** - * struct tdb_attribute_hash - hash function attribute - * - * This attribute allows you to provide an alternative hash function. - * This hash function will be handed keys from the database; it will also - * be handed the 8-byte TDB_HASH_MAGIC value for checking the header (the - * tdb_open() will fail if the hash value doesn't match the header). - * - * Note that if your hash function gives different results on - * different machine endians, your tdb will no longer work across - * different architectures! - */ -struct tdb_attribute_hash { - struct tdb_attribute_base base; /* .attr = TDB_ATTRIBUTE_HASH */ - uint64_t (*fn)(const void *key, size_t len, uint64_t seed, - void *data); - void *data; -}; - -/** - * struct tdb_attribute_seed - hash function seed attribute - * - * The hash function seed is normally taken from /dev/urandom (or equivalent) - * but can be set manually here. This is mainly for testing purposes. - */ -struct tdb_attribute_seed { - struct tdb_attribute_base base; /* .attr = TDB_ATTRIBUTE_SEED */ - uint64_t seed; -}; - -/** - * struct tdb_attribute_stats - tdb operational statistics - * - * This attribute records statistics of various low-level TDB operations. - * This can be used to assist performance evaluation. This is only - * useful for tdb_get_attribute(). - * - * New fields will be added at the end, hence the "size" argument which - * indicates how large your structure is: it must be filled in before - * calling tdb_get_attribute(), which will overwrite it with the size - * tdb knows about. - */ -struct tdb_attribute_stats { - struct tdb_attribute_base base; /* .attr = TDB_ATTRIBUTE_STATS */ - size_t size; /* = sizeof(struct tdb_attribute_stats) */ - uint64_t allocs; - uint64_t alloc_subhash; - uint64_t alloc_chain; - uint64_t alloc_bucket_exact; - uint64_t alloc_bucket_max; - uint64_t alloc_leftover; - uint64_t alloc_coalesce_tried; - uint64_t alloc_coalesce_iterate_clash; - uint64_t alloc_coalesce_lockfail; - uint64_t alloc_coalesce_race; - uint64_t alloc_coalesce_succeeded; - uint64_t alloc_coalesce_num_merged; - uint64_t compares; - uint64_t compare_wrong_bucket; - uint64_t compare_wrong_offsetbits; - uint64_t compare_wrong_keylen; - uint64_t compare_wrong_rechash; - uint64_t compare_wrong_keycmp; - uint64_t transactions; - uint64_t transaction_cancel; - uint64_t transaction_nest; - uint64_t transaction_expand_file; - uint64_t transaction_read_direct; - uint64_t transaction_read_direct_fail; - uint64_t transaction_write_direct; - uint64_t transaction_write_direct_fail; - uint64_t expands; - uint64_t frees; - uint64_t locks; - uint64_t lock_lowlevel; - uint64_t lock_nonblock; - uint64_t lock_nonblock_fail; -}; - -/** - * struct tdb_attribute_openhook - tdb special effects hook for open - * - * This attribute contains a function to call once we have the OPEN_LOCK - * for the tdb, but before we've examined its contents. If this succeeds, - * the tdb will be populated if it's then zero-length. - * - * This is a hack to allow support for TDB1-style TDB_CLEAR_IF_FIRST - * behaviour. - */ -struct tdb_attribute_openhook { - struct tdb_attribute_base base; /* .attr = TDB_ATTRIBUTE_OPENHOOK */ - enum TDB_ERROR (*fn)(int fd, void *data); - void *data; -}; - -/** - * struct tdb_attribute_flock - tdb special effects hook for file locking - * - * This attribute contains function to call to place locks on a file; it can - * be used to support non-blocking operations or lock proxying. - * - * They should return 0 on success, -1 on failure and set errno. - * - * An error will be logged on error if errno is neither EAGAIN nor EINTR - * (normally it would only return EAGAIN if waitflag is false, and - * loop internally on EINTR). - */ -struct tdb_attribute_flock { - struct tdb_attribute_base base; /* .attr = TDB_ATTRIBUTE_FLOCK */ - int (*lock)(int fd,int rw, off_t off, off_t len, bool waitflag, void *); - int (*unlock)(int fd, int rw, off_t off, off_t len, void *); - void *data; -}; - -/** - * struct tdb_attribute_tdb1_hashsize - tdb1 hashsize - * - * This attribute allows setting the TDB1 hashsize; it only makes sense with - * O_CREAT and TDB_VERSION1. - * - * Hashsize should generally be a prime, such as 10007. - */ -struct tdb_attribute_tdb1_hashsize { - struct tdb_attribute_base base; /* .attr = TDB_ATTRIBUTE_TDB1_HASHSIZE */ - unsigned int hsize; -}; - -/** - * struct tdb_attribute_tdb1_max_dead - tdb1 number of maximum dead records. - * - * TDB1 has a method to speed up its slow free list: it lets a certain - * number of "dead" records build up before freeing them. This is - * particularly useful for volatile TDBs; setting it to 5 is - * equivalent to tdb1's TDB_VOLATILE flag. - */ -struct tdb_attribute_tdb1_max_dead { - struct tdb_attribute_base base; /* .attr = TDB_ATTRIBUTE_TDB1_MAX_DEAD */ - unsigned int max_dead; -}; - -/** - * union tdb_attribute - tdb attributes. - * - * This represents all the known attributes. - * - * See also: - * struct tdb_attribute_log, struct tdb_attribute_hash, - * struct tdb_attribute_seed, struct tdb_attribute_stats, - * struct tdb_attribute_openhook, struct tdb_attribute_flock. - */ -union tdb_attribute { - struct tdb_attribute_base base; - struct tdb_attribute_log log; - struct tdb_attribute_hash hash; - struct tdb_attribute_seed seed; - struct tdb_attribute_stats stats; - struct tdb_attribute_openhook openhook; - struct tdb_attribute_flock flock; - struct tdb_attribute_tdb1_hashsize tdb1_hashsize; - struct tdb_attribute_tdb1_max_dead tdb1_max_dead; -}; - -#ifdef __cplusplus -} -#endif - -#endif /* tdb2.h */