#ifndef CCAN_TDB2_H
#define CCAN_TDB2_H
-/*
- Unix SMB/CIFS implementation.
-
- trivial database library
+/*
+ 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
#endif
#ifndef _SAMBA_BUILD_
+#include "config.h"
+#if HAVE_FILE_OFFSET_BITS
+#define _FILE_OFFSET_BITS 64
+#endif
/* For mode_t */
#include <sys/types.h>
/* For O_* flags. */
#include <signal.h>
/* For uint64_t */
#include <stdint.h>
+/* For bool */
+#include <stdbool.h>
+/* For memcmp */
+#include <string.h>
#endif
+#include <ccan/compiler/compiler.h>
+#include <ccan/typesafe_cb/typesafe_cb.h>
+#include <ccan/cast/cast.h>
+
+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 to tdb_store() */
-#define TDB_REPLACE 1 /* Unused */
-#define TDB_INSERT 2 /* Don't overwrite an existing entry */
-#define TDB_MODIFY 3 /* Don't create an existing entry */
/* flags for tdb_open() */
#define TDB_DEFAULT 0 /* just a readability place holder */
-#define TDB_CLEAR_IF_FIRST 1
#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_VOLATILE 256 /* Activate the per-hashchain freelist, default 5 */
-#define TDB_ALLOW_NESTING 512 /* Allow transactions to nest */
+#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 */
-/* error codes */
-enum TDB_ERROR {TDB_SUCCESS=0, TDB_ERR_CORRUPT, TDB_ERR_IO, TDB_ERR_LOCK,
- TDB_ERR_OOM, TDB_ERR_EXISTS, TDB_ERR_NOEXIST,
- TDB_ERR_EINVAL, TDB_ERR_RDONLY, TDB_ERR_NESTING };
+/**
+ * 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 *);
-/* debugging uses one of the following levels */
-enum tdb_debug_level {TDB_DEBUG_FATAL = 0, TDB_DEBUG_ERROR,
- TDB_DEBUG_WARNING, TDB_DEBUG_TRACE};
+/**
+ * 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;
-#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
+/**
+ * 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
+};
-struct tdb_context;
+/**
+ * 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);
-/* FIXME: Make typesafe */
-typedef int (*tdb_traverse_func)(struct tdb_context *, TDB_DATA, TDB_DATA, void *);
-typedef void (*tdb_logfn_t)(struct tdb_context *, enum tdb_debug_level, void *priv, const char *, ...) PRINTF_ATTRIBUTE(4, 5);
-typedef uint64_t (*tdb_hashfn_t)(const void *key, size_t len, uint64_t seed,
- void *priv);
+/**
+ * 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_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 */
- tdb_logfn_t log_fn;
- void *log_private;
+ 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 */
- tdb_hashfn_t hash_fn;
- void *hash_private;
+ 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;
};
-
-struct tdb_context *tdb_open(const char *name, int tdb_flags,
- int open_flags, mode_t mode,
- union tdb_attribute *attributes);
-
-struct tdb_data tdb_fetch(struct tdb_context *tdb, struct tdb_data key);
-int tdb_delete(struct tdb_context *tdb, struct tdb_data key);
-int tdb_store(struct tdb_context *tdb, struct tdb_data key, struct tdb_data dbuf, int flag);
-int tdb_append(struct tdb_context *tdb, struct tdb_data key, struct tdb_data dbuf);
-int tdb_chainlock(struct tdb_context *tdb, TDB_DATA key);
-int tdb_chainunlock(struct tdb_context *tdb, TDB_DATA key);
-int64_t tdb_traverse(struct tdb_context *tdb, tdb_traverse_func fn, void *p);
-int64_t tdb_traverse_read(struct tdb_context *tdb,
- tdb_traverse_func fn, void *p);
-TDB_DATA tdb_firstkey(struct tdb_context *tdb);
-TDB_DATA tdb_nextkey(struct tdb_context *tdb, TDB_DATA key);
-int tdb_close(struct tdb_context *tdb);
-int tdb_check(struct tdb_context *tdb,
- int (*check)(TDB_DATA key, TDB_DATA data, void *private_data),
- void *private_data);
-
-enum TDB_ERROR tdb_error(struct tdb_context *tdb);
-const char *tdb_errorstr(struct tdb_context *tdb);
-
-extern struct tdb_data tdb_null;
#ifdef __cplusplus
}
projects / ccan / blobdiff