/*
- * $Id: ad_lock.c,v 1.16 2009-10-21 10:49:36 didg Exp $
+ * $Id: ad_lock.c,v 1.20 2010-03-30 12:55:26 franklahm Exp $
*
* Copyright (c) 1998,1999 Adrian Sun (asun@zoology.washington.edu)
* All Rights Reserved. See COPYRIGHT for more information.
#define fcntl(a, b, c ) (0)
#endif
+/* ----------------------- */
+static int set_lock(int fd, int cmd, struct flock *lock)
+{
+ if (fd == -2) {
+ /* We assign fd = -2 for symlinks -> do nothing */
+ if (cmd == F_GETLK)
+ lock->l_type = F_UNLCK;
+ return 0;
+ }
+ return fcntl(fd, cmd, lock);
+}
+
/* ----------------------- */
static int XLATE_FCNTL_LOCK(int type)
{
free(lock->refcount);
if (!ad->adf_excl) {
lock->lock.l_type = F_UNLCK;
- fcntl(ad->adf_fd, F_SETLK, &lock->lock); /* unlock */
+ set_lock(ad->adf_fd, F_SETLK, &lock->lock); /* unlock */
}
}
int i;
for (i = 0; i < ad->adf_lockcount; i++) {
+
if (lock[i].user == fork) {
/* we're really going to delete this lock. note: read locks
are the only ones that allow refcounts > 1 */
adf_freelock(ad, i);
i--; /* we shifted things down, so we need to backtrack */
- }
+ /* unlikely but realloc may have change adf_lock */
+ lock = ad->adf_lock;
+ }
}
}
if (!ad->adf_excl) for (i = 0; i < ad->adf_lockcount; i++) {
if (OVERLAP(off, len, lock[i].lock.l_start, lock[i].lock.l_len))
- fcntl(fd, F_SETLK, &lock[i].lock);
+ set_lock(fd, F_SETLK, &lock[i].lock);
}
}
* 2) if the header file doesn't exist, we stick the locks
* in the locations specified by AD_FILELOCK_RD/WR.
*/
-#define LOCK_RSRC_RD (0)
-#define LOCK_RSRC_WR (1)
-#define LOCK_DATA_RD (2)
-#define LOCK_DATA_WR (3)
+#define LOCK_DATA_WR (0)
+#define LOCK_DATA_RD (1)
+#define LOCK_RSRC_WR (2)
+#define LOCK_RSRC_RD (3)
#define LOCK_RSRC_DRD (4)
#define LOCK_RSRC_DWR (5)
}
/* attempt to lock the file. */
- if (!adf->adf_excl && fcntl(adf->adf_fd, F_SETLK, &lock) < 0)
+ if (!adf->adf_excl && set_lock(adf->adf_fd, F_SETLK, &lock) < 0)
return -1;
/* we upgraded this lock. */
fcntl_lock_err:
lock.l_type = F_UNLCK;
- if (!adf->adf_excl) fcntl(adf->adf_fd, F_SETLK, &lock);
+ if (!adf->adf_excl) set_lock(adf->adf_fd, F_SETLK, &lock);
return -1;
}
error ==> -1
*/
-int ad_testlock(struct adouble *ad, int eid, const off_t off)
+static int testlock(struct ad_fd *adf, off_t off, off_t len)
{
struct flock lock;
- struct ad_fd *adf;
adf_lock_t *plock;
int i;
lock.l_start = off;
- if (eid == ADEID_DFORK) {
- adf = &ad->ad_data_fork;
- if ((ad_meta_fileno(ad) != -1)) {
- adf = ad->ad_md;
- lock.l_start = df2off(off);
- }
- }
- else { /* rfork */
- if ((ad_meta_fileno(ad) == -1)) {
- /* there's no resource fork. return no lock */
- return 0;
- }
- adf = ad->ad_md;
- lock.l_start = hf2off(off);
- }
plock = adf->adf_lock;
- /* Do we have a lock? */
lock.l_whence = SEEK_SET;
- lock.l_len = 1;
+ lock.l_len = len;
+
+ /* Do we have a lock? */
for (i = 0; i < adf->adf_lockcount; i++) {
if (OVERLAP(lock.l_start, 1, plock[i].lock.l_start, plock[i].lock.l_len))
return 1; /* */
}
/* Does another process have a lock?
*/
- lock.l_type = (adf->adf_flags & O_RDWR) ?F_WRLCK : F_RDLCK;
+ lock.l_type = (adf->adf_flags & O_RDWR) ?F_WRLCK : F_RDLCK;
- if (fcntl(adf->adf_fd, F_GETLK, &lock) < 0) {
+ if (set_lock(adf->adf_fd, F_GETLK, &lock) < 0) {
/* is that kind of error possible ?*/
return (errno == EACCES || errno == EAGAIN)?1:-1;
}
return 1;
}
+/* --------------- */
+int ad_testlock(struct adouble *ad, int eid, const off_t off)
+{
+ struct ad_fd *adf;
+ off_t lock_offset;
+
+ lock_offset = off;
+ if (eid == ADEID_DFORK) {
+ adf = &ad->ad_data_fork;
+ if (ad_meta_fileno(ad) != -1) {
+ adf = ad->ad_md;
+ lock_offset = df2off(off);
+ }
+ }
+ else { /* rfork */
+ if (ad_meta_fileno(ad) == -1) {
+ /* there's no resource fork. return no lock */
+ return 0;
+ }
+ adf = ad->ad_md;
+ lock_offset = hf2off(off);
+ }
+ return testlock(adf, lock_offset, 1);
+}
+
+/* -------------------------
+ return if a file is open by another process.
+ Optimized for the common case:
+ - there's no locks held by another process (clients)
+ - or we already know the answer and don't need to test.
+*/
+u_int16_t ad_openforks(struct adouble *ad, u_int16_t attrbits)
+{
+ u_int16_t ret = 0;
+ struct ad_fd *adf;
+ off_t off;
+
+ if (!(attrbits & (ATTRBIT_DOPEN | ATTRBIT_ROPEN))) {
+ off_t len;
+ /* XXX know the locks layout:
+ AD_FILELOCK_OPEN_WR is first
+ and use it for merging requests
+ */
+ if (ad_meta_fileno(ad) != -1) {
+ /* there's a resource fork test the four bytes for
+ * data RW/RD and fork RW/RD locks in one request
+ */
+ adf = ad->ad_md;
+ off = LOCK_DATA_WR;
+ len = 4;
+ }
+ else {
+ /* no resource fork, only data RD/RW may exist */
+ adf = &ad->ad_data_fork;
+ off = AD_FILELOCK_OPEN_WR;
+ len = 2;
+ }
+ if (!testlock(adf, off, len))
+ return ret;
+ }
+ /* either there's a lock or we already know one
+ fork is open
+ */
+ if (!(attrbits & ATTRBIT_DOPEN)) {
+ if (ad_meta_fileno(ad) != -1) {
+ adf = ad->ad_md;
+ off = LOCK_DATA_WR;
+ }
+ else {
+ adf = &ad->ad_data_fork;
+ off = AD_FILELOCK_OPEN_WR;
+ }
+ ret = testlock(adf, off, 2) > 0? ATTRBIT_DOPEN : 0;
+ }
+
+ if (!(attrbits & ATTRBIT_ROPEN)) {
+ if (ad_meta_fileno(ad) != -1) {
+ adf = ad->ad_md;
+ off = LOCK_RSRC_WR;
+ ret |= testlock(adf, off, 2) > 0? ATTRBIT_ROPEN : 0;
+ }
+ }
+
+ return ret;
+}
+
/* -------------------------
*/
int ad_fcntl_tmplock(struct adouble *ad, const u_int32_t eid, const int locktype,
* we just want to upgrade all the locks and then downgrade them
* here. */
if (!adf->adf_excl) {
- err = fcntl(adf->adf_fd, F_SETLK, &lock);
+ err = set_lock(adf->adf_fd, F_SETLK, &lock);
}
else {
err = 0;
lock.l_start = ad_getentryoff(ad, eid);
}
- err = fcntl(adf->adf_fd, F_SETLK, &lock);
+ err = set_lock(adf->adf_fd, F_SETLK, &lock);
if (!err)
adf->adf_excl = 1;
return err;
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