diff options
Diffstat (limited to 'common/tdb.c')
| -rw-r--r-- | common/tdb.c | 1348 |
1 files changed, 1348 insertions, 0 deletions
diff --git a/common/tdb.c b/common/tdb.c new file mode 100644 index 0000000..de829bb --- /dev/null +++ b/common/tdb.c @@ -0,0 +1,1348 @@ + /* + 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" + +_PUBLIC_ TDB_DATA tdb_null; + +/* + non-blocking increment of the tdb sequence number if the tdb has been opened using + the TDB_SEQNUM flag +*/ +_PUBLIC_ void tdb_increment_seqnum_nonblock(struct tdb_context *tdb) +{ + tdb_off_t seqnum=0; + + if (!(tdb->flags & TDB_SEQNUM)) { + return; + } + + /* we ignore errors from this, as we have no sane way of + dealing with them. + */ + tdb_ofs_read(tdb, TDB_SEQNUM_OFS, &seqnum); + seqnum++; + tdb_ofs_write(tdb, TDB_SEQNUM_OFS, &seqnum); +} + +/* + increment the tdb sequence number if the tdb has been opened using + the TDB_SEQNUM flag +*/ +static void tdb_increment_seqnum(struct tdb_context *tdb) +{ + if (!(tdb->flags & TDB_SEQNUM)) { + return; + } + + if (tdb->transaction != NULL) { + tdb_increment_seqnum_nonblock(tdb); + return; + } + +#if defined(HAVE___ATOMIC_ADD_FETCH) && defined(HAVE___ATOMIC_ADD_LOAD) + if (tdb->map_ptr != NULL) { + uint32_t *pseqnum = (uint32_t *)( + TDB_SEQNUM_OFS + (char *)tdb->map_ptr); + __atomic_add_fetch(pseqnum, 1, __ATOMIC_SEQ_CST); + return; + } +#endif + + if (tdb_nest_lock(tdb, TDB_SEQNUM_OFS, F_WRLCK, + TDB_LOCK_WAIT|TDB_LOCK_PROBE) != 0) { + return; + } + + tdb_increment_seqnum_nonblock(tdb); + + tdb_nest_unlock(tdb, TDB_SEQNUM_OFS, F_WRLCK, false); +} + +static int tdb_key_compare(TDB_DATA key, TDB_DATA data, void *private_data) +{ + return memcmp(data.dptr, key.dptr, data.dsize); +} + +void tdb_chainwalk_init(struct tdb_chainwalk_ctx *ctx, tdb_off_t ptr) +{ + *ctx = (struct tdb_chainwalk_ctx) { .slow_ptr = ptr }; +} + +bool tdb_chainwalk_check(struct tdb_context *tdb, + struct tdb_chainwalk_ctx *ctx, + tdb_off_t next_ptr) +{ + int ret; + + if (ctx->slow_chase) { + ret = tdb_ofs_read(tdb, ctx->slow_ptr, &ctx->slow_ptr); + if (ret == -1) { + return false; + } + } + ctx->slow_chase = !ctx->slow_chase; + + if (next_ptr == ctx->slow_ptr) { + tdb->ecode = TDB_ERR_CORRUPT; + TDB_LOG((tdb, TDB_DEBUG_ERROR, + "tdb_chainwalk_check: circular chain\n")); + return false; + } + + return true; +} + +/* Returns 0 on fail. On success, return offset of record, and fills + in rec */ +static tdb_off_t tdb_find(struct tdb_context *tdb, TDB_DATA key, uint32_t hash, + struct tdb_record *r) +{ + tdb_off_t rec_ptr; + struct tdb_chainwalk_ctx chainwalk; + + /* read in the hash top */ + if (tdb_ofs_read(tdb, TDB_HASH_TOP(hash), &rec_ptr) == -1) + return 0; + + tdb_chainwalk_init(&chainwalk, rec_ptr); + + /* keep looking until we find the right record */ + while (rec_ptr) { + bool ok; + + if (tdb_rec_read(tdb, rec_ptr, r) == -1) + return 0; + + if (!TDB_DEAD(r) && hash==r->full_hash + && key.dsize==r->key_len + && tdb_parse_data(tdb, key, rec_ptr + sizeof(*r), + r->key_len, tdb_key_compare, + NULL) == 0) { + return rec_ptr; + } + rec_ptr = r->next; + + ok = tdb_chainwalk_check(tdb, &chainwalk, rec_ptr); + if (!ok) { + return 0; + } + } + tdb->ecode = TDB_ERR_NOEXIST; + return 0; +} + +/* As tdb_find, but if you succeed, keep the lock */ +tdb_off_t tdb_find_lock_hash(struct tdb_context *tdb, TDB_DATA key, uint32_t hash, int locktype, + struct tdb_record *rec) +{ + uint32_t rec_ptr; + + if (tdb_lock(tdb, BUCKET(hash), locktype) == -1) + return 0; + if (!(rec_ptr = tdb_find(tdb, key, hash, rec))) + tdb_unlock(tdb, BUCKET(hash), locktype); + return rec_ptr; +} + +static TDB_DATA _tdb_fetch(struct tdb_context *tdb, TDB_DATA key); + +struct tdb_update_hash_state { + const TDB_DATA *dbufs; + int num_dbufs; + tdb_len_t dbufs_len; +}; + +static int tdb_update_hash_cmp(TDB_DATA key, TDB_DATA data, void *private_data) +{ + struct tdb_update_hash_state *state = private_data; + unsigned char *dptr = data.dptr; + int i; + + if (state->dbufs_len != data.dsize) { + return -1; + } + + for (i=0; i<state->num_dbufs; i++) { + TDB_DATA dbuf = state->dbufs[i]; + if( dbuf.dsize > 0) { + int ret; + ret = memcmp(dptr, dbuf.dptr, dbuf.dsize); + if (ret != 0) { + return -1; + } + dptr += dbuf.dsize; + } + } + + return 0; +} + +/* 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 tdb_update_hash(struct tdb_context *tdb, TDB_DATA key, + uint32_t hash, + const TDB_DATA *dbufs, int num_dbufs, + tdb_len_t dbufs_len) +{ + struct tdb_record rec; + tdb_off_t rec_ptr, ofs; + int i; + + /* find entry */ + if (!(rec_ptr = tdb_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.data_len == dbufs_len) { + struct tdb_update_hash_state state = { + .dbufs = dbufs, .num_dbufs = num_dbufs, + .dbufs_len = dbufs_len + }; + int ret; + + ret = tdb_parse_record(tdb, key, tdb_update_hash_cmp, &state); + if (ret == 0) { + return 0; + } + } + + /* must be long enough key, data and tailer */ + if (rec.rec_len < key.dsize + dbufs_len + sizeof(tdb_off_t)) { + tdb->ecode = TDB_SUCCESS; /* Not really an error */ + return -1; + } + + ofs = rec_ptr + sizeof(rec) + rec.key_len; + + for (i=0; i<num_dbufs; i++) { + TDB_DATA dbuf = dbufs[i]; + int ret; + + ret = tdb->methods->tdb_write(tdb, ofs, dbuf.dptr, dbuf.dsize); + if (ret == -1) { + return -1; + } + ofs += dbuf.dsize; + } + + if (dbufs_len != rec.data_len) { + /* update size */ + rec.data_len = dbufs_len; + return tdb_rec_write(tdb, rec_ptr, &rec); + } + + return 0; +} + +/* find an entry in the database given a key */ +/* If an entry doesn't exist tdb_err will be set to + * TDB_ERR_NOEXIST. If a key has no data attached + * then the TDB_DATA will have zero length but + * a non-zero pointer + */ +static TDB_DATA _tdb_fetch(struct tdb_context *tdb, TDB_DATA key) +{ + tdb_off_t rec_ptr; + struct tdb_record rec; + TDB_DATA ret; + uint32_t hash; + + /* find which hash bucket it is in */ + hash = tdb->hash_fn(&key); + if (!(rec_ptr = tdb_find_lock_hash(tdb,key,hash,F_RDLCK,&rec))) + return tdb_null; + + ret.dptr = tdb_alloc_read(tdb, rec_ptr + sizeof(rec) + rec.key_len, + rec.data_len); + ret.dsize = rec.data_len; + tdb_unlock(tdb, BUCKET(rec.full_hash), F_RDLCK); + return ret; +} + +_PUBLIC_ TDB_DATA tdb_fetch(struct tdb_context *tdb, TDB_DATA key) +{ + TDB_DATA ret = _tdb_fetch(tdb, key); + + tdb_trace_1rec_retrec(tdb, "tdb_fetch", key, ret); + 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 tdb_parse_record(struct tdb_context *tdb, TDB_DATA key, + int (*parser)(TDB_DATA key, TDB_DATA data, + void *private_data), + void *private_data) +{ + tdb_off_t rec_ptr; + struct tdb_record rec; + int ret; + uint32_t hash; + + /* find which hash bucket it is in */ + hash = tdb->hash_fn(&key); + + if (!(rec_ptr = tdb_find_lock_hash(tdb,key,hash,F_RDLCK,&rec))) { + /* record not found */ + tdb_trace_1rec_ret(tdb, "tdb_parse_record", key, -1); + tdb->ecode = TDB_ERR_NOEXIST; + return -1; + } + tdb_trace_1rec_ret(tdb, "tdb_parse_record", key, 0); + + ret = tdb_parse_data(tdb, key, rec_ptr + sizeof(rec) + rec.key_len, + rec.data_len, parser, private_data); + + tdb_unlock(tdb, 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 tdb_exists_hash(struct tdb_context *tdb, TDB_DATA key, uint32_t hash) +{ + struct tdb_record rec; + + if (tdb_find_lock_hash(tdb, key, hash, F_RDLCK, &rec) == 0) + return 0; + tdb_unlock(tdb, BUCKET(rec.full_hash), F_RDLCK); + return 1; +} + +_PUBLIC_ int tdb_exists(struct tdb_context *tdb, TDB_DATA key) +{ + uint32_t hash = tdb->hash_fn(&key); + int ret; + + ret = tdb_exists_hash(tdb, key, hash); + tdb_trace_1rec_ret(tdb, "tdb_exists", key, ret); + return ret; +} + +/* + * Move a dead record to the freelist. The hash chain and freelist + * must be locked. + */ +static int tdb_del_dead(struct tdb_context *tdb, + uint32_t last_ptr, + uint32_t rec_ptr, + struct tdb_record *rec, + bool *deleted) +{ + int ret; + + ret = tdb_write_lock_record(tdb, rec_ptr); + if (ret == -1) { + /* Someone traversing here: Just leave it dead */ + return 0; + } + ret = tdb_write_unlock_record(tdb, rec_ptr); + if (ret == -1) { + return -1; + } + ret = tdb_ofs_write(tdb, last_ptr, &rec->next); + if (ret == -1) { + return -1; + } + + *deleted = true; + + ret = tdb_free(tdb, rec_ptr, rec); + return ret; +} + +/* + * Walk the hash chain and leave tdb->max_dead_records around. Move + * the rest of dead records to the freelist. + */ +int tdb_trim_dead(struct tdb_context *tdb, uint32_t hash) +{ + struct tdb_chainwalk_ctx chainwalk; + struct tdb_record rec; + tdb_off_t last_ptr, rec_ptr; + bool locked_freelist = false; + int num_dead = 0; + int ret; + + last_ptr = TDB_HASH_TOP(hash); + + /* + * Init chainwalk with the pointer to the hash top. It might + * be that the very first record in the chain is a dead one + * that we have to delete. + */ + tdb_chainwalk_init(&chainwalk, last_ptr); + + ret = tdb_ofs_read(tdb, last_ptr, &rec_ptr); + if (ret == -1) { + return -1; + } + + while (rec_ptr != 0) { + bool deleted = false; + uint32_t next; + + ret = tdb_rec_read(tdb, rec_ptr, &rec); + if (ret == -1) { + goto fail; + } + + /* + * Make a copy of rec.next: Further down we might + * delete and put the record on the freelist. Make + * sure that modifications in that code path can't + * break the chainwalk here. + */ + next = rec.next; + + if (rec.magic == TDB_DEAD_MAGIC) { + num_dead += 1; + + if (num_dead > tdb->max_dead_records) { + + if (!locked_freelist) { + /* + * Lock the freelist only if + * it's really required. + */ + ret = tdb_lock(tdb, -1, F_WRLCK); + if (ret == -1) { + goto fail; + }; + locked_freelist = true; + } + + ret = tdb_del_dead( + tdb, + last_ptr, + rec_ptr, + &rec, + &deleted); + + if (ret == -1) { + goto fail; + } + } + } + + /* + * Don't do the chainwalk check if "rec_ptr" was + * deleted. We reduced the chain, and the chainwalk + * check might catch up early. Imagine a valid chain + * with just dead records: We never can bump the + * "slow" pointer in chainwalk_check, as there isn't + * anything left to jump to and compare. + */ + if (!deleted) { + bool ok; + + last_ptr = rec_ptr; + + ok = tdb_chainwalk_check(tdb, &chainwalk, next); + if (!ok) { + ret = -1; + goto fail; + } + } + rec_ptr = next; + } + ret = 0; +fail: + if (locked_freelist) { + tdb_unlock(tdb, -1, F_WRLCK); + } + return ret; +} + +/* delete an entry in the database given a key */ +static int tdb_delete_hash(struct tdb_context *tdb, TDB_DATA key, uint32_t hash) +{ + tdb_off_t rec_ptr; + struct tdb_record rec; + int ret; + + if (tdb->read_only || tdb->traverse_read) { + tdb->ecode = TDB_ERR_RDONLY; + return -1; + } + + rec_ptr = tdb_find_lock_hash(tdb, key, hash, F_WRLCK, &rec); + if (rec_ptr == 0) { + return -1; + } + + /* + * Mark the record dead + */ + rec.magic = TDB_DEAD_MAGIC; + ret = tdb_rec_write(tdb, rec_ptr, &rec); + if (ret == -1) { + goto done; + } + + tdb_increment_seqnum(tdb); + + ret = tdb_trim_dead(tdb, hash); +done: + if (tdb_unlock(tdb, BUCKET(hash), F_WRLCK) != 0) + TDB_LOG((tdb, TDB_DEBUG_WARNING, "tdb_delete: WARNING tdb_unlock failed!\n")); + return ret; +} + +_PUBLIC_ int tdb_delete(struct tdb_context *tdb, TDB_DATA key) +{ + uint32_t hash = tdb->hash_fn(&key); + int ret; + + ret = tdb_delete_hash(tdb, key, hash); + tdb_trace_1rec_ret(tdb, "tdb_delete", key, ret); + return ret; +} + +/* + * See if we have a dead record around with enough space + */ +tdb_off_t tdb_find_dead(struct tdb_context *tdb, uint32_t hash, + struct tdb_record *r, tdb_len_t length, + tdb_off_t *p_last_ptr) +{ + tdb_off_t rec_ptr, last_ptr; + struct tdb_chainwalk_ctx chainwalk; + tdb_off_t best_rec_ptr = 0; + tdb_off_t best_last_ptr = 0; + struct tdb_record best = { .rec_len = UINT32_MAX }; + + length += sizeof(tdb_off_t); /* tailer */ + + last_ptr = TDB_HASH_TOP(hash); + + /* read in the hash top */ + if (tdb_ofs_read(tdb, last_ptr, &rec_ptr) == -1) + return 0; + + tdb_chainwalk_init(&chainwalk, rec_ptr); + + /* keep looking until we find the right record */ + while (rec_ptr) { + bool ok; + + if (tdb_rec_read(tdb, rec_ptr, r) == -1) + return 0; + + if (TDB_DEAD(r) && (r->rec_len >= length) && + (r->rec_len < best.rec_len)) { + best_rec_ptr = rec_ptr; + best_last_ptr = last_ptr; + best = *r; + } + last_ptr = rec_ptr; + rec_ptr = r->next; + + ok = tdb_chainwalk_check(tdb, &chainwalk, rec_ptr); + if (!ok) { + return 0; + } + } + + if (best.rec_len == UINT32_MAX) { + return 0; + } + + *r = best; + *p_last_ptr = best_last_ptr; + return best_rec_ptr; +} + +static int _tdb_storev(struct tdb_context *tdb, TDB_DATA key, + const TDB_DATA *dbufs, int num_dbufs, + int flag, uint32_t hash) +{ + struct tdb_record rec; + tdb_off_t rec_ptr, ofs; + tdb_len_t rec_len, dbufs_len; + int i; + int ret = -1; + + dbufs_len = 0; + + for (i=0; i<num_dbufs; i++) { + size_t dsize = dbufs[i].dsize; + + if ((dsize != 0) && (dbufs[i].dptr == NULL)) { + tdb->ecode = TDB_ERR_EINVAL; + goto fail; + } + + dbufs_len += dsize; + if (dbufs_len < dsize) { + tdb->ecode = TDB_ERR_OOM; + goto fail; + } + } + + rec_len = key.dsize + dbufs_len; + if ((rec_len < key.dsize) || (rec_len < dbufs_len)) { + tdb->ecode = TDB_ERR_OOM; + goto fail; + } + + /* check for it existing, on insert. */ + if (flag == TDB_INSERT) { + if (tdb_exists_hash(tdb, key, hash)) { + tdb->ecode = TDB_ERR_EXISTS; + goto fail; + } + } else { + /* first try in-place update, on modify or replace. */ + if (tdb_update_hash(tdb, key, hash, dbufs, num_dbufs, + dbufs_len) == 0) { + goto done; + } + if (tdb->ecode == TDB_ERR_NOEXIST && + flag == TDB_MODIFY) { + /* if the record doesn't exist and we are in TDB_MODIFY mode then + we should fail the store */ + goto fail; + } + } + /* reset the error code potentially set by the tdb_update_hash() */ + tdb->ecode = TDB_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 != TDB_INSERT) + tdb_delete_hash(tdb, key, hash); + + /* we have to allocate some space */ + rec_ptr = tdb_allocate(tdb, hash, rec_len, &rec); + + if (rec_ptr == 0) { + goto fail; + } + + /* Read hash top into next ptr */ + if (tdb_ofs_read(tdb, TDB_HASH_TOP(hash), &rec.next) == -1) + goto fail; + + rec.key_len = key.dsize; + rec.data_len = dbufs_len; + rec.full_hash = hash; + rec.magic = TDB_MAGIC; + + ofs = rec_ptr; + + /* write out and point the top of the hash chain at it */ + ret = tdb_rec_write(tdb, ofs, &rec); + if (ret == -1) { + goto fail; + } + ofs += sizeof(rec); + + ret = tdb->methods->tdb_write(tdb, ofs, key.dptr, key.dsize); + if (ret == -1) { + goto fail; + } + ofs += key.dsize; + + for (i=0; i<num_dbufs; i++) { + if (dbufs[i].dsize == 0) { + continue; + } + + ret = tdb->methods->tdb_write(tdb, ofs, dbufs[i].dptr, + dbufs[i].dsize); + if (ret == -1) { + goto fail; + } + ofs += dbufs[i].dsize; + } + + ret = tdb_ofs_write(tdb, TDB_HASH_TOP(hash), &rec_ptr); + if (ret == -1) { + /* Need to tdb_unallocate() here */ + goto fail; + } + + done: + ret = 0; + fail: + if (ret == 0) { + tdb_increment_seqnum(tdb); + } + return ret; +} + +static int _tdb_store(struct tdb_context *tdb, TDB_DATA key, + TDB_DATA dbuf, int flag, uint32_t hash) +{ + return _tdb_storev(tdb, key, &dbuf, 1, flag, hash); +} + +/* store an element in the database, replacing any existing element + with the same key + + return 0 on success, -1 on failure +*/ +_PUBLIC_ int tdb_store(struct tdb_context *tdb, TDB_DATA key, TDB_DATA dbuf, int flag) +{ + uint32_t hash; + int ret; + + if (tdb->read_only || tdb->traverse_read) { + tdb->ecode = TDB_ERR_RDONLY; + tdb_trace_2rec_flag_ret(tdb, "tdb_store", key, dbuf, flag, -1); + return -1; + } + + /* find which hash bucket it is in */ + hash = tdb->hash_fn(&key); + if (tdb_lock(tdb, BUCKET(hash), F_WRLCK) == -1) + return -1; + + ret = _tdb_store(tdb, key, dbuf, flag, hash); + tdb_trace_2rec_flag_ret(tdb, "tdb_store", key, dbuf, flag, ret); + tdb_unlock(tdb, BUCKET(hash), F_WRLCK); + return ret; +} + +_PUBLIC_ int tdb_storev(struct tdb_context *tdb, TDB_DATA key, + const TDB_DATA *dbufs, int num_dbufs, int flag) +{ + uint32_t hash; + int ret; + + if (tdb->read_only || tdb->traverse_read) { + tdb->ecode = TDB_ERR_RDONLY; + tdb_trace_1plusn_rec_flag_ret(tdb, "tdb_storev", key, + dbufs, num_dbufs, flag, -1); + return -1; + } + + /* find which hash bucket it is in */ + hash = tdb->hash_fn(&key); + if (tdb_lock(tdb, BUCKET(hash), F_WRLCK) == -1) + return -1; + + ret = _tdb_storev(tdb, key, dbufs, num_dbufs, flag, hash); + tdb_trace_1plusn_rec_flag_ret(tdb, "tdb_storev", key, + dbufs, num_dbufs, flag, -1); + tdb_unlock(tdb, BUCKET(hash), F_WRLCK); + return ret; +} + +/* Append to an entry. Create if not exist. */ +_PUBLIC_ int tdb_append(struct tdb_context *tdb, TDB_DATA key, TDB_DATA new_dbuf) +{ + uint32_t hash; + TDB_DATA dbufs[2]; + int ret = -1; + + /* find which hash bucket it is in */ + hash = tdb->hash_fn(&key); + if (tdb_lock(tdb, BUCKET(hash), F_WRLCK) == -1) + return -1; + + dbufs[0] = _tdb_fetch(tdb, key); + dbufs[1] = new_dbuf; + + ret = _tdb_storev(tdb, key, dbufs, 2, 0, hash); + tdb_trace_2rec_retrec(tdb, "tdb_append", key, dbufs[0], dbufs[1]); + + tdb_unlock(tdb, BUCKET(hash), F_WRLCK); + SAFE_FREE(dbufs[0].dptr); + return ret; +} + + +/* + return the name of the current tdb file + useful for external logging functions +*/ +_PUBLIC_ const char *tdb_name(struct tdb_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 tdb_fd(struct tdb_context *tdb) +{ + return tdb->fd; +} + +/* + return the current logging function + useful for external tdb routines that wish to log tdb errors +*/ +_PUBLIC_ tdb_log_func tdb_log_fn(struct tdb_context *tdb) +{ + return tdb->log.log_fn; +} + + +/* + get the tdb sequence number. Only makes sense if the writers opened + with TDB_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 tdb_get_seqnum(struct tdb_context *tdb) +{ + tdb_off_t seqnum=0; + + if (tdb->transaction != NULL) { + tdb_ofs_read(tdb, TDB_SEQNUM_OFS, &seqnum); + return seqnum; + } + +#if defined(HAVE___ATOMIC_ADD_FETCH) && defined(HAVE___ATOMIC_ADD_LOAD) + if (tdb->map_ptr != NULL) { + uint32_t *pseqnum = (uint32_t *)( + TDB_SEQNUM_OFS + (char *)tdb->map_ptr); + uint32_t ret; + __atomic_load(pseqnum, &ret,__ATOMIC_SEQ_CST); + return ret; + } +#endif + + tdb_ofs_read(tdb, TDB_SEQNUM_OFS, &seqnum); + return seqnum; +} + +_PUBLIC_ int tdb_hash_size(struct tdb_context *tdb) +{ + return tdb->hash_size; +} + +_PUBLIC_ size_t tdb_map_size(struct tdb_context *tdb) +{ + return tdb->map_size; +} + +_PUBLIC_ int tdb_get_flags(struct tdb_context *tdb) +{ + return tdb->flags; +} + +_PUBLIC_ void tdb_add_flags(struct tdb_context *tdb, unsigned flags) +{ + if ((flags & TDB_ALLOW_NESTING) && + (flags & TDB_DISALLOW_NESTING)) { + tdb->ecode = TDB_ERR_NESTING; + TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_add_flags: " + "allow_nesting and disallow_nesting are not allowed together!")); + return; + } + + if (flags & TDB_ALLOW_NESTING) { + tdb->flags &= ~TDB_DISALLOW_NESTING; + } + if (flags & TDB_DISALLOW_NESTING) { + tdb->flags &= ~TDB_ALLOW_NESTING; + } + + tdb->flags |= flags; +} + +_PUBLIC_ void tdb_remove_flags(struct tdb_context *tdb, unsigned flags) +{ + if ((flags & TDB_ALLOW_NESTING) && + (flags & TDB_DISALLOW_NESTING)) { + tdb->ecode = TDB_ERR_NESTING; + TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_remove_flags: " + "allow_nesting and disallow_nesting are not allowed together!")); + return; + } + + if ((flags & TDB_NOLOCK) && + (tdb->feature_flags & TDB_FEATURE_FLAG_MUTEX) && + (tdb->mutexes == NULL)) { + tdb->ecode = TDB_ERR_LOCK; + TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_remove_flags: " + "Can not remove NOLOCK flag on mutexed databases")); + return; + } + + if (flags & TDB_ALLOW_NESTING) { + tdb->flags |= TDB_DISALLOW_NESTING; + } + if (flags & TDB_DISALLOW_NESTING) { + tdb->flags |= TDB_ALLOW_NESTING; + } + + tdb->flags &= ~flags; +} + + +/* + enable sequence number handling on an open tdb +*/ +_PUBLIC_ void tdb_enable_seqnum(struct tdb_context *tdb) +{ + tdb->flags |= TDB_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 tdb_free_region(struct tdb_context *tdb, tdb_off_t offset, ssize_t length) +{ + struct tdb_record rec; + if (length <= sizeof(rec)) { + /* the region is not worth adding */ + return 0; + } + if (length + offset > tdb->map_size) { + TDB_LOG((tdb, TDB_DEBUG_FATAL,"tdb_free_region: adding region beyond end of file\n")); + return -1; + } + memset(&rec,'\0',sizeof(rec)); + rec.rec_len = length - sizeof(rec); + if (tdb_free(tdb, offset, &rec) == -1) { + TDB_LOG((tdb, TDB_DEBUG_FATAL,"tdb_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 tdb_wipe_all(struct tdb_context *tdb) +{ + uint32_t i; + tdb_off_t offset = 0; + ssize_t data_len; + tdb_off_t recovery_head; + tdb_len_t recovery_size = 0; + + if (tdb_lockall(tdb) != 0) { + return -1; + } + + tdb_trace(tdb, "tdb_wipe_all"); + + /* see if the tdb has a recovery area, and remember its size + if so. We don't want to lose this as otherwise each + tdb_wipe_all() in a transaction will increase the size of + the tdb by the size of the recovery area */ + if (tdb_ofs_read(tdb, TDB_RECOVERY_HEAD, &recovery_head) == -1) { + TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_wipe_all: failed to read recovery head\n")); + goto failed; + } + + if (recovery_head != 0) { + struct tdb_record rec; + if (tdb->methods->tdb_read(tdb, recovery_head, &rec, sizeof(rec), DOCONV()) == -1) { + TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_wipe_all: failed to read recovery record\n")); + return -1; + } + recovery_size = rec.rec_len + sizeof(rec); + } + + /* wipe the hashes */ + for (i=0;i<tdb->hash_size;i++) { + if (tdb_ofs_write(tdb, TDB_HASH_TOP(i), &offset) == -1) { + TDB_LOG((tdb, TDB_DEBUG_FATAL,"tdb_wipe_all: failed to write hash %d\n", i)); + goto failed; + } + } + + /* wipe the freelist */ + if (tdb_ofs_write(tdb, FREELIST_TOP, &offset) == -1) { + TDB_LOG((tdb, TDB_DEBUG_FATAL,"tdb_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 - TDB_DATA_START(tdb->hash_size)); + if (tdb_free_region(tdb, TDB_DATA_START(tdb->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 - TDB_DATA_START(tdb->hash_size)); + if (tdb_free_region(tdb, TDB_DATA_START(tdb->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 (tdb_free_region(tdb, recovery_head+recovery_size, data_len) != 0) { + goto failed; + } + } + + tdb_increment_seqnum_nonblock(tdb); + + if (tdb_unlockall(tdb) != 0) { + TDB_LOG((tdb, TDB_DEBUG_FATAL,"tdb_wipe_all: failed to unlock\n")); + goto failed; + } + + return 0; + +failed: + tdb_unlockall(tdb); + return -1; +} + +struct traverse_state { + bool error; + struct tdb_context *dest_db; +}; + +/* + traverse function for repacking + */ +static int repack_traverse(struct tdb_context *tdb, TDB_DATA key, TDB_DATA data, void *private_data) +{ + struct traverse_state *state = (struct traverse_state *)private_data; + if (tdb_store(state->dest_db, key, data, TDB_INSERT) != 0) { + state->error = true; + return -1; + } + return 0; +} + +/* + repack a tdb + */ +_PUBLIC_ int tdb_repack(struct tdb_context *tdb) +{ + struct tdb_context *tmp_db; + struct traverse_state state; + + tdb_trace(tdb, "tdb_repack"); + + if (tdb_transaction_start(tdb) != 0) { + TDB_LOG((tdb, TDB_DEBUG_FATAL, __location__ " Failed to start transaction\n")); + return -1; + } + + tmp_db = tdb_open("tmpdb", tdb_hash_size(tdb), TDB_INTERNAL, O_RDWR|O_CREAT, 0); + if (tmp_db == NULL) { + TDB_LOG((tdb, TDB_DEBUG_FATAL, __location__ " Failed to create tmp_db\n")); + tdb_transaction_cancel(tdb); + return -1; + } + + state.error = false; + state.dest_db = tmp_db; + + if (tdb_traverse_read(tdb, repack_traverse, &state) == -1) { + TDB_LOG((tdb, TDB_DEBUG_FATAL, __location__ " Failed to traverse copying out\n")); + tdb_transaction_cancel(tdb); + tdb_close(tmp_db); + return -1; + } + + if (state.error) { + TDB_LOG((tdb, TDB_DEBUG_FATAL, __location__ " Error during traversal\n")); + tdb_transaction_cancel(tdb); + tdb_close(tmp_db); + return -1; + } + + if (tdb_wipe_all(tdb) != 0) { + TDB_LOG((tdb, TDB_DEBUG_FATAL, __location__ " Failed to wipe database\n")); + tdb_transaction_cancel(tdb); + tdb_close(tmp_db); + return -1; + } + + state.error = false; + state.dest_db = tdb; + + if (tdb_traverse_read(tmp_db, repack_traverse, &state) == -1) { + TDB_LOG((tdb, TDB_DEBUG_FATAL, __location__ " Failed to traverse copying back\n")); + tdb_transaction_cancel(tdb); + tdb_close(tmp_db); + return -1; + } + + if (state.error) { + TDB_LOG((tdb, TDB_DEBUG_FATAL, __location__ " Error during second traversal\n")); + tdb_transaction_cancel(tdb); + tdb_close(tmp_db); + return -1; + } + + tdb_close(tmp_db); + + if (tdb_transaction_commit(tdb) != 0) { + TDB_LOG((tdb, TDB_DEBUG_FATAL, __location__ " Failed to commit\n")); + return -1; + } + + return 0; +} + +/* Even on files, we can get partial writes due to signals. */ +bool tdb_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; +} + +bool tdb_add_off_t(tdb_off_t a, tdb_off_t b, tdb_off_t *pret) +{ + tdb_off_t ret = a + b; + + if ((ret < a) || (ret < b)) { + return false; + } + *pret = ret; + return true; +} + +#ifdef TDB_TRACE +static void tdb_trace_write(struct tdb_context *tdb, const char *str) +{ + if (!tdb_write_all(tdb->tracefd, str, strlen(str))) { + close(tdb->tracefd); + tdb->tracefd = -1; + } +} + +static void tdb_trace_start(struct tdb_context *tdb) +{ + tdb_off_t seqnum=0; + char msg[sizeof(tdb_off_t) * 4 + 1]; + + tdb_ofs_read(tdb, TDB_SEQNUM_OFS, &seqnum); + snprintf(msg, sizeof(msg), "%u ", seqnum); + tdb_trace_write(tdb, msg); +} + +static void tdb_trace_end(struct tdb_context *tdb) +{ + tdb_trace_write(tdb, "\n"); +} + +static void tdb_trace_end_ret(struct tdb_context *tdb, int ret) +{ + char msg[sizeof(ret) * 4 + 4]; + snprintf(msg, sizeof(msg), " = %i\n", ret); + tdb_trace_write(tdb, msg); +} + +static void tdb_trace_record(struct tdb_context *tdb, TDB_DATA rec) +{ + char msg[20 + rec.dsize*2], *p; + unsigned int i; + + /* We differentiate zero-length records from non-existent ones. */ + if (rec.dptr == NULL) { + tdb_trace_write(tdb, " NULL"); + return; + } + + /* snprintf here is purely cargo-cult programming. */ + p = msg; + p += snprintf(p, sizeof(msg), " %zu:", rec.dsize); + for (i = 0; i < rec.dsize; i++) + p += snprintf(p, 2, "%02x", rec.dptr[i]); + + tdb_trace_write(tdb, msg); +} + +void tdb_trace(struct tdb_context *tdb, const char *op) +{ + tdb_trace_start(tdb); + tdb_trace_write(tdb, op); + tdb_trace_end(tdb); +} + +void tdb_trace_seqnum(struct tdb_context *tdb, uint32_t seqnum, const char *op) +{ + char msg[sizeof(tdb_off_t) * 4 + 1]; + + snprintf(msg, sizeof(msg), "%u ", seqnum); + tdb_trace_write(tdb, msg); + tdb_trace_write(tdb, op); + tdb_trace_end(tdb); +} + +void tdb_trace_open(struct tdb_context *tdb, const char *op, + unsigned hash_size, unsigned tdb_flags, unsigned open_flags) +{ + char msg[128]; + + snprintf(msg, sizeof(msg), + "%s %u 0x%x 0x%x", op, hash_size, tdb_flags, open_flags); + tdb_trace_start(tdb); + tdb_trace_write(tdb, msg); + tdb_trace_end(tdb); +} + +void tdb_trace_ret(struct tdb_context *tdb, const char *op, int ret) +{ + tdb_trace_start(tdb); + tdb_trace_write(tdb, op); + tdb_trace_end_ret(tdb, ret); +} + +void tdb_trace_retrec(struct tdb_context *tdb, const char *op, TDB_DATA ret) +{ + tdb_trace_start(tdb); + tdb_trace_write(tdb, op); + tdb_trace_write(tdb, " ="); + tdb_trace_record(tdb, ret); + tdb_trace_end(tdb); +} + +void tdb_trace_1rec(struct tdb_context *tdb, const char *op, + TDB_DATA rec) +{ + tdb_trace_start(tdb); + tdb_trace_write(tdb, op); + tdb_trace_record(tdb, rec); + tdb_trace_end(tdb); +} + +void tdb_trace_1rec_ret(struct tdb_context *tdb, const char *op, + TDB_DATA rec, int ret) +{ + tdb_trace_start(tdb); + tdb_trace_write(tdb, op); + tdb_trace_record(tdb, rec); + tdb_trace_end_ret(tdb, ret); +} + +void tdb_trace_1rec_retrec(struct tdb_context *tdb, const char *op, + TDB_DATA rec, TDB_DATA ret) +{ + tdb_trace_start(tdb); + tdb_trace_write(tdb, op); + tdb_trace_record(tdb, rec); + tdb_trace_write(tdb, " ="); + tdb_trace_record(tdb, ret); + tdb_trace_end(tdb); +} + +void tdb_trace_2rec_flag_ret(struct tdb_context *tdb, const char *op, + TDB_DATA rec1, TDB_DATA rec2, unsigned flag, + int ret) +{ + char msg[1 + sizeof(ret) * 4]; + + snprintf(msg, sizeof(msg), " %#x", flag); + tdb_trace_start(tdb); + tdb_trace_write(tdb, op); + tdb_trace_record(tdb, rec1); + tdb_trace_record(tdb, rec2); + tdb_trace_write(tdb, msg); + tdb_trace_end_ret(tdb, ret); +} + +void tdb_trace_1plusn_rec_flag_ret(struct tdb_context *tdb, const char *op, + TDB_DATA rec, + const TDB_DATA *recs, int num_recs, + unsigned flag, int ret) +{ + char msg[1 + sizeof(ret) * 4]; + int i; + + snprintf(msg, sizeof(msg), " %#x", flag); + tdb_trace_start(tdb); + tdb_trace_write(tdb, op); + tdb_trace_record(tdb, rec); + for (i=0; i<num_recs; i++) { + tdb_trace_record(tdb, recs[i]); + } + tdb_trace_write(tdb, msg); + tdb_trace_end_ret(tdb, ret); +} + +void tdb_trace_2rec_retrec(struct tdb_context *tdb, const char *op, + TDB_DATA rec1, TDB_DATA rec2, TDB_DATA ret) +{ + tdb_trace_start(tdb); + tdb_trace_write(tdb, op); + tdb_trace_record(tdb, rec1); + tdb_trace_record(tdb, rec2); + tdb_trace_write(tdb, " ="); + tdb_trace_record(tdb, ret); + tdb_trace_end(tdb); +} +#endif |