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#include <tdb_compat.h>
/* Note: for the moment, we only need this file for TDB2, so we can
* assume waf. */
#if BUILD_TDB2
TDB_DATA tdb_null = { NULL, 0 };
/* Proxy which sets waitflag to false so we never block. */
static int lock_nonblock(int fd, int rw, off_t off, off_t len, bool waitflag,
void *_orig)
{
struct tdb_attribute_flock *orig = _orig;
return orig->lock(fd, rw, off, len, false, orig->data);
}
enum TDB_ERROR tdb_transaction_start_nonblock(struct tdb_context *tdb)
{
union tdb_attribute locking, orig;
enum TDB_ERROR ecode;
orig.base.attr = TDB_ATTRIBUTE_FLOCK;
ecode = tdb_get_attribute(tdb, &orig);
if (ecode != TDB_SUCCESS)
return ecode;
/* Replace locking function with our own. */
locking = orig;
locking.flock.data = &orig;
locking.flock.lock = lock_nonblock;
ecode = tdb_set_attribute(tdb, &locking);
if (ecode != TDB_SUCCESS)
return ecode;
ecode = tdb_transaction_start(tdb);
tdb_unset_attribute(tdb, TDB_ATTRIBUTE_FLOCK);
return ecode;
}
/*
* This handles TDB_CLEAR_IF_FIRST.
*/
static enum TDB_ERROR clear_if_first(int fd, void *unused)
{
/* We hold a lock offset 63 always, so we can tell if anyone else is. */
struct flock fl;
fl.l_type = F_WRLCK;
fl.l_whence = SEEK_SET;
fl.l_start = 63;
fl.l_len = 1;
if (fcntl(fd, F_SETLK, &fl) == 0) {
/* We must be first ones to open it w/ TDB_CLEAR_IF_FIRST! */
if (ftruncate(fd, 0) != 0) {
return TDB_ERR_IO;
}
}
fl.l_type = F_RDLCK;
if (fcntl(fd, F_SETLKW, &fl) != 0) {
return TDB_ERR_IO;
}
return TDB_SUCCESS;
}
struct tdb_context *
tdb_open_compat_(const char *name, int hash_size_unused,
int tdb_flags, int open_flags, mode_t mode,
void (*log_fn)(struct tdb_context *,
enum tdb_log_level,
const char *message,
void *data),
void *log_data)
{
union tdb_attribute cif, log, *attr = NULL;
if (log_fn) {
log.log.base.attr = TDB_ATTRIBUTE_LOG;
log.log.base.next = NULL;
log.log.fn = log_fn;
log.log.data = log_data;
attr = &log;
}
if (tdb_flags & TDB_CLEAR_IF_FIRST) {
cif.openhook.base.attr = TDB_ATTRIBUTE_OPENHOOK;
cif.openhook.base.next = attr;
cif.openhook.fn = clear_if_first;
attr = &cif;
tdb_flags &= ~TDB_CLEAR_IF_FIRST;
}
return tdb_open(name, tdb_flags|TDB_ALLOW_NESTING, open_flags, mode,
attr);
}
#endif
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