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author | Tom Lane <tgl@sss.pgh.pa.us> | 2004-11-09 20:35:16 +0000 |
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committer | Tom Lane <tgl@sss.pgh.pa.us> | 2004-11-09 20:35:16 +0000 |
commit | 176bb0812fe46e117b8a185ff70abf95bb87a792 (patch) | |
tree | a6aba9eae1b379def336d0204e855a5d2a892a47 /src | |
parent | 3392959b6ee9574ff3928715ab204a3210eb4e67 (diff) | |
download | postgresql-176bb0812fe46e117b8a185ff70abf95bb87a792.tar.gz postgresql-176bb0812fe46e117b8a185ff70abf95bb87a792.zip |
In PGSharedMemoryIsInUse, assume that EACCES indicates a shmem segment
that is of no concern to us --- it must belong to a different userid,
which means it is not a Postgres shmem segment (or at least,
not one that is relevant to our data directory). I plan a more extensive
fix in HEAD, but this is a simple change that prevents failure-to-reboot
problems for single-postmaster installations.
Diffstat (limited to 'src')
-rw-r--r-- | src/backend/port/sysv_shmem.c | 19 |
1 files changed, 13 insertions, 6 deletions
diff --git a/src/backend/port/sysv_shmem.c b/src/backend/port/sysv_shmem.c index 9ec046071c9..b44f07c8ec5 100644 --- a/src/backend/port/sysv_shmem.c +++ b/src/backend/port/sysv_shmem.c @@ -10,7 +10,7 @@ * Portions Copyright (c) 1994, Regents of the University of California * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/port/sysv_shmem.c,v 1.24.2.1 2003/11/07 21:56:01 tgl Exp $ + * $Header: /cvsroot/pgsql/src/backend/port/sysv_shmem.c,v 1.24.2.2 2004/11/09 20:35:16 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -191,10 +191,6 @@ PGSharedMemoryIsInUse(unsigned long id1, unsigned long id2) /* * We detect whether a shared memory segment is in use by seeing * whether it (a) exists and (b) has any processes are attached to it. - * - * If we are unable to perform the stat operation for a reason other than - * nonexistence of the segment (most likely, because it doesn't belong - * to our userid), assume it is in use. */ if (shmctl(shmId, IPC_STAT, &shmStat) < 0) { @@ -205,7 +201,18 @@ PGSharedMemoryIsInUse(unsigned long id1, unsigned long id2) */ if (errno == EINVAL) return false; - /* Else assume segment is in use */ + /* + * EACCES implies that the segment belongs to some other userid, + * which means it is not a Postgres shmem segment (or at least, + * not one that is relevant to our data directory). + */ + if (errno == EACCES) + return false; + /* + * Otherwise, we had better assume that the segment is in use. + * The only likely case is EIDRM, which implies that the segment + * has been IPC_RMID'd but there are still processes attached to it. + */ return true; } /* If it has attached processes, it's in use */ |