1 #include <tdb_compat.h>
3 /* Note: for the moment, we only need this file for TDB2, so we can
6 TDB_DATA tdb_null = { NULL, 0 };
8 /* Proxy which sets waitflag to false so we never block. */
9 static int lock_nonblock(int fd, int rw, off_t off, off_t len, bool waitflag,
12 struct tdb_attribute_flock *orig = _orig;
14 return orig->lock(fd, rw, off, len, false, orig->data);
17 enum TDB_ERROR tdb_transaction_start_nonblock(struct tdb_context *tdb)
19 union tdb_attribute locking, orig;
22 orig.base.attr = TDB_ATTRIBUTE_FLOCK;
23 ecode = tdb_get_attribute(tdb, &orig);
24 if (ecode != TDB_SUCCESS)
27 /* Replace locking function with our own. */
29 locking.flock.data = &orig;
30 locking.flock.lock = lock_nonblock;
32 ecode = tdb_set_attribute(tdb, &locking);
33 if (ecode != TDB_SUCCESS)
36 ecode = tdb_transaction_start(tdb);
37 tdb_unset_attribute(tdb, TDB_ATTRIBUTE_FLOCK);
41 /* For TDB1 tdbs, read traverse vs normal matters: write traverse
42 locks the entire thing! */
43 int64_t tdb_traverse_read_(struct tdb_context *tdb,
44 int (*fn)(struct tdb_context *,
51 if (tdb_get_flags(tdb) & TDB_RDONLY) {
52 return tdb_traverse(tdb, fn, p);
55 tdb_add_flag(tdb, TDB_RDONLY);
56 ret = tdb_traverse(tdb, fn, p);
57 tdb_remove_flag(tdb, TDB_RDONLY);
62 * This handles TDB_CLEAR_IF_FIRST.
64 static enum TDB_ERROR clear_if_first(int fd, void *unused)
66 /* We hold a lock offset 4 always, so we can tell if anyone else is. */
70 fl.l_whence = SEEK_SET;
71 fl.l_start = 4; /* ACTIVE_LOCK */
74 if (fcntl(fd, F_SETLK, &fl) == 0) {
75 /* We must be first ones to open it w/ TDB_CLEAR_IF_FIRST! */
76 if (ftruncate(fd, 0) != 0) {
81 if (fcntl(fd, F_SETLKW, &fl) != 0) {
88 tdb_open_compat_(const char *name, int hash_size_unused,
89 int tdb_flags, int open_flags, mode_t mode,
90 void (*log_fn)(struct tdb_context *,
97 union tdb_attribute cif, log, hash, max_dead, *attr = NULL;
100 log.log.base.attr = TDB_ATTRIBUTE_LOG;
101 log.log.base.next = NULL;
103 log.log.data = log_data;
107 if (tdb_flags & TDB_CLEAR_IF_FIRST) {
108 cif.openhook.base.attr = TDB_ATTRIBUTE_OPENHOOK;
109 cif.openhook.base.next = attr;
110 cif.openhook.fn = clear_if_first;
112 tdb_flags &= ~TDB_CLEAR_IF_FIRST;
115 if (tdb_flags & TDB_INCOMPATIBLE_HASH) {
116 if (tdb_flags & TDB_VERSION1) {
117 hash.hash.base.attr = TDB_ATTRIBUTE_HASH;
118 hash.hash.base.next = attr;
119 hash.hash.fn = tdb1_incompatible_hash;
122 tdb_flags &= ~TDB_INCOMPATIBLE_HASH;
125 if (tdb_flags & TDB_VOLATILE) {
126 if (tdb_flags & TDB_VERSION1) {
127 max_dead.base.attr = TDB_ATTRIBUTE_TDB1_MAX_DEAD;
128 max_dead.base.next = attr;
129 max_dead.tdb1_max_dead.max_dead = 5;
132 tdb_flags &= ~TDB_VOLATILE;
135 /* Testsuite uses this to speed things up. */
136 if (getenv("TDB_NO_FSYNC")) {
137 tdb_flags |= TDB_NOSYNC;
140 return tdb_open(name, tdb_flags|TDB_ALLOW_NESTING, open_flags, mode,
144 /* We only need these for the CLEAR_IF_FIRST lock. */
145 static int reacquire_cif_lock(struct tdb_context *tdb, bool *fail)
148 union tdb_attribute cif;
150 cif.openhook.base.attr = TDB_ATTRIBUTE_OPENHOOK;
151 cif.openhook.base.next = NULL;
153 if (tdb_get_attribute(tdb, &cif) != TDB_SUCCESS
154 || cif.openhook.fn != clear_if_first) {
158 /* We hold a lock offset 4 always, so we can tell if anyone else is. */
160 fl.l_whence = SEEK_SET;
161 fl.l_start = 4; /* ACTIVE_LOCK */
163 if (fcntl(tdb_fd(tdb), F_SETLKW, &fl) != 0) {
170 int tdb_reopen(struct tdb_context *tdb)
173 return reacquire_cif_lock(tdb, &unused);
176 int tdb_reopen_all(int parent_longlived)
180 if (parent_longlived) {
184 tdb_foreach(reacquire_cif_lock, &fail);