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Posted to commits@apr.apache.org by ji...@apache.org on 2003/02/23 17:40:31 UTC
cvs commit: apr/locks/unix proc_mutex.c
jim 2003/02/23 08:40:31
Modified: . CHANGES
locks/unix proc_mutex.c
Log:
When we generate our own semaphore name (internally) when using
Posix semaphores, initially try a name more unique (which unfortunately
may also be larger than the least-common-denominator in names).
If that fails, however, we gracefully use the old naming mechanism.
Revision Changes Path
1.380 +3 -0 apr/CHANGES
Index: CHANGES
===================================================================
RCS file: /home/cvs/apr/CHANGES,v
retrieving revision 1.379
retrieving revision 1.380
diff -u -r1.379 -r1.380
--- CHANGES 17 Feb 2003 03:47:10 -0000 1.379
+++ CHANGES 23 Feb 2003 16:40:31 -0000 1.380
@@ -1,5 +1,8 @@
Changes with APR 0.9.2
+ *) When generating a semaphore name for posixsem locking, try to
+ be a little more robust (and unique). [Jim Jagielski]
+
*) Add functions apr_env_get, apr_env_set and apr_env_delete for
manipulating the environment. [Branko Cibej]
1.28 +23 -7 apr/locks/unix/proc_mutex.c
Index: proc_mutex.c
===================================================================
RCS file: /home/cvs/apr/locks/unix/proc_mutex.c,v
retrieving revision 1.27
retrieving revision 1.28
diff -u -r1.27 -r1.28
--- proc_mutex.c 7 Jan 2003 00:52:55 -0000 1.27
+++ proc_mutex.c 23 Feb 2003 16:40:31 -0000 1.28
@@ -91,9 +91,10 @@
{
sem_t *psem;
apr_status_t stat;
- char semname[14];
+ char semname[31];
apr_time_t now;
- unsigned long epoch;
+ unsigned long sec;
+ unsigned long usec;
new_mutex->interproc = apr_palloc(new_mutex->pool,
sizeof(*new_mutex->interproc));
@@ -104,20 +105,34 @@
* - be at most 14 chars
* - be unique and not match anything on the filesystem
*
- * Because of this, we ignore fname and craft our own.
+ * Because of this, we ignore fname, and try our
+ * own naming system. We tuck the name away, since it might
+ * be useful for debugging. to make this as robust as possible,
+ * we initially try something larger (and hopefully more unique)
+ * and gracefully fail down to the LCD above.
+ *
+ * NOTE: Darwin (Mac OS X) seems to be the most restrictive
+ * implementation. Versions previous to Darwin 6.2 had the 14
+ * char limit, but later rev's allow up to 31 characters.
*
* FIXME: There is a small window of opportunity where
* instead of getting a new semaphore descriptor, we get
* a previously obtained one. This can happen if the requests
- * are made at the "same time" (within a second, due to the
- * apr_time_now() call) and in the small span of time between
+ * are made at the "same time" and in the small span of time between
* the sem_open and the sem_unlink. Use of O_EXCL does not
* help here however...
+ *
*/
now = apr_time_now();
- epoch = apr_time_sec(now);
- apr_snprintf(semname, sizeof(semname), "/ApR.%lx", epoch);
+ sec = apr_time_sec(now);
+ usec = apr_time_usec(now);
+ apr_snprintf(semname, sizeof(semname), "/ApR.%lxZ%lx", sec, usec);
psem = sem_open((const char *) semname, O_CREAT, 0644, 1);
+ if ((psem == (sem_t *)SEM_FAILED) && (errno == ENAMETOOLONG)) {
+ /* Oh well, good try */
+ semname[13] = '\0';
+ psem = sem_open((const char *) semname, O_CREAT, 0644, 1);
+ }
if (psem == (sem_t *)SEM_FAILED) {
stat = errno;
@@ -127,6 +142,7 @@
/* Ahhh. The joys of Posix sems. Predelete it... */
sem_unlink((const char *) semname);
new_mutex->interproc->filedes = (int)psem; /* Ugg */
+ new_mutex->fname = apr_pstrdup(new_mutex->pool, semname);
apr_pool_cleanup_register(new_mutex->pool, (void *)new_mutex,
apr_proc_mutex_cleanup,
apr_pool_cleanup_null);