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-rw-r--r--source3/lib/util_tdb.c96
1 files changed, 96 insertions, 0 deletions
diff --git a/source3/lib/util_tdb.c b/source3/lib/util_tdb.c
index 4756fd84ef..ade46bf18e 100644
--- a/source3/lib/util_tdb.c
+++ b/source3/lib/util_tdb.c
@@ -28,6 +28,101 @@
#undef calloc
#undef strdup
+#ifdef BUILD_TDB2
+static struct flock flock_struct;
+
+/* Return a value which is none of v1, v2 or v3. */
+static inline short int invalid_value(short int v1, short int v2, short int v3)
+{
+ short int try = (v1+v2+v3)^((v1+v2+v3) << 16);
+ while (try == v1 || try == v2 || try == v3)
+ try++;
+ return try;
+}
+
+/* We invalidate in as many ways as we can, so the OS rejects it */
+static void invalidate_flock_struct(int signum)
+{
+ flock_struct.l_type = invalid_value(F_RDLCK, F_WRLCK, F_UNLCK);
+ flock_struct.l_whence = invalid_value(SEEK_SET, SEEK_CUR, SEEK_END);
+ flock_struct.l_start = -1;
+ /* A large negative. */
+ flock_struct.l_len = (((off_t)1 << (sizeof(off_t)*CHAR_BIT - 1)) + 1);
+}
+
+static int timeout_lock(int fd, int rw, off_t off, off_t len, bool waitflag,
+ void *_timeout)
+{
+ int ret, saved_errno;
+ unsigned int timeout = *(unsigned int *)_timeout;
+
+ flock_struct.l_type = rw;
+ flock_struct.l_whence = SEEK_SET;
+ flock_struct.l_start = off;
+ flock_struct.l_len = len;
+
+ CatchSignal(SIGALRM, invalidate_flock_struct);
+ alarm(timeout);
+
+ for (;;) {
+ if (waitflag)
+ ret = fcntl(fd, F_SETLKW, &flock_struct);
+ else
+ ret = fcntl(fd, F_SETLK, &flock_struct);
+
+ if (ret == 0)
+ break;
+
+ /* Not signalled? Something else went wrong. */
+ if (flock_struct.l_len == len) {
+ if (errno == EAGAIN || errno == EINTR)
+ continue;
+ saved_errno = errno;
+ break;
+ } else {
+ saved_errno = EINTR;
+ break;
+ }
+ }
+
+ alarm(0);
+ errno = saved_errno;
+ return ret;
+}
+
+static int tdb_chainlock_with_timeout_internal(struct tdb_context *tdb,
+ TDB_DATA key,
+ unsigned int timeout,
+ int rw_type)
+{
+ union tdb_attribute locking;
+ enum TDB_ERROR ecode;
+
+ if (timeout) {
+ locking.base.attr = TDB_ATTRIBUTE_FLOCK;
+ ecode = tdb_get_attribute(tdb, &locking);
+ if (ecode != TDB_SUCCESS)
+ return ecode;
+
+ /* Replace locking function with our own. */
+ locking.flock.data = &timeout;
+ locking.flock.lock = timeout_lock;
+
+ ecode = tdb_set_attribute(tdb, &locking);
+ if (ecode != TDB_SUCCESS)
+ return ecode;
+ }
+ if (rw_type == F_RDLCK)
+ ecode = tdb_chainlock_read(tdb, key);
+ else
+ ecode = tdb_chainlock(tdb, key);
+
+ if (timeout) {
+ tdb_unset_attribute(tdb, TDB_ATTRIBUTE_FLOCK);
+ }
+ return ecode == TDB_SUCCESS ? 0 : -1;
+}
+#else
/* these are little tdb utility functions that are meant to make
dealing with a tdb database a little less cumbersome in Samba */
@@ -80,6 +175,7 @@ static int tdb_chainlock_with_timeout_internal( TDB_CONTEXT *tdb, TDB_DATA key,
return ret == 0 ? 0 : -1;
}
+#endif /* TDB1 */
/****************************************************************************
Write lock a chain. Return non-zero if timeout or lock failed.