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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;
}
enum TDB_ERROR tdb_chainlock_nonblock(struct tdb_context *tdb, TDB_DATA key)
{
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_chainlock(tdb, key);
tdb_unset_attribute(tdb, TDB_ATTRIBUTE_FLOCK);
return ecode;
}
/* For TDB1 tdbs, read traverse vs normal matters: write traverse
locks the entire thing! */
int64_t tdb_traverse_read_(struct tdb_context *tdb,
int (*fn)(struct tdb_context *,
TDB_DATA, TDB_DATA,
void *),
void *p)
{
int64_t ret;
if (tdb_get_flags(tdb) & TDB_RDONLY) {
return tdb_traverse(tdb, fn, p);
}
tdb_add_flag(tdb, TDB_RDONLY);
ret = tdb_traverse(tdb, fn, p);
tdb_remove_flag(tdb, TDB_RDONLY);
return ret;
}
/*
* This handles TDB_CLEAR_IF_FIRST.
*/
static enum TDB_ERROR clear_if_first(int fd, void *unused)
{
/* We hold a lock offset 4 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 = 4; /* ACTIVE_LOCK */
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,
int tdb_flags, int open_flags, mode_t mode,
void (*log_fn)(struct tdb_context *,
enum tdb_log_level,
enum TDB_ERROR,
const char *message,
void *data),
void *log_data)
{
union tdb_attribute cif, log, hash, max_dead, hsize, *attr = NULL;
if (!getenv("TDB_COMPAT_USE_TDB2")) {
tdb_flags |= TDB_VERSION1;
}
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;
}
if (tdb_flags & TDB_INCOMPATIBLE_HASH) {
if (tdb_flags & TDB_VERSION1) {
hash.hash.base.attr = TDB_ATTRIBUTE_HASH;
hash.hash.base.next = attr;
hash.hash.fn = tdb1_incompatible_hash;
attr = &hash;
}
tdb_flags &= ~TDB_INCOMPATIBLE_HASH;
}
if (tdb_flags & TDB_VOLATILE) {
if (tdb_flags & TDB_VERSION1) {
max_dead.base.attr = TDB_ATTRIBUTE_TDB1_MAX_DEAD;
max_dead.base.next = attr;
max_dead.tdb1_max_dead.max_dead = 5;
attr = &max_dead;
}
tdb_flags &= ~TDB_VOLATILE;
}
if (hash_size && (tdb_flags & TDB_VERSION1) && (open_flags & O_CREAT)) {
hsize.base.attr = TDB_ATTRIBUTE_TDB1_HASHSIZE;
hsize.base.next = attr;
hsize.tdb1_hashsize.hsize = hash_size;
attr = &hsize;
}
/* Testsuite uses this to speed things up. */
if (getenv("TDB_NO_FSYNC")) {
tdb_flags |= TDB_NOSYNC;
}
return tdb_open(name, tdb_flags|TDB_ALLOW_NESTING, open_flags, mode,
attr);
}
/* We only need these for the CLEAR_IF_FIRST lock. */
static int reacquire_cif_lock(struct tdb_context *tdb, bool *fail)
{
struct flock fl;
union tdb_attribute cif;
cif.openhook.base.attr = TDB_ATTRIBUTE_OPENHOOK;
cif.openhook.base.next = NULL;
if (tdb_get_attribute(tdb, &cif) != TDB_SUCCESS
|| cif.openhook.fn != clear_if_first) {
return 0;
}
/* We hold a lock offset 4 always, so we can tell if anyone else is. */
fl.l_type = F_RDLCK;
fl.l_whence = SEEK_SET;
fl.l_start = 4; /* ACTIVE_LOCK */
fl.l_len = 1;
if (fcntl(tdb_fd(tdb), F_SETLKW, &fl) != 0) {
*fail = true;
return -1;
}
return 0;
}
int tdb_reopen(struct tdb_context *tdb)
{
bool unused;
return reacquire_cif_lock(tdb, &unused);
}
int tdb_reopen_all(int parent_longlived)
{
bool fail = false;
if (parent_longlived) {
return 0;
}
tdb_foreach(reacquire_cif_lock, &fail);
if (fail)
return -1;
return 0;
}
#endif
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