diff options
Diffstat (limited to 'src/backend/storage/ipc/ipc.c')
| -rw-r--r-- | src/backend/storage/ipc/ipc.c | 40 |
1 files changed, 39 insertions, 1 deletions
diff --git a/src/backend/storage/ipc/ipc.c b/src/backend/storage/ipc/ipc.c index c529547fcfe..eb8d488bdd3 100644 --- a/src/backend/storage/ipc/ipc.c +++ b/src/backend/storage/ipc/ipc.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/storage/ipc/ipc.c,v 1.62 2001/01/24 19:43:07 momjian Exp $ + * $Header: /cvsroot/pgsql/src/backend/storage/ipc/ipc.c,v 1.63 2001/03/13 01:17:06 tgl Exp $ * * NOTES * @@ -626,6 +626,9 @@ InternalIpcMemoryCreate(IpcMemoryKey memKey, uint32 size, int permission) /* Register on-exit routine to detach new segment before deleting */ on_shmem_exit(IpcMemoryDetach, PointerGetDatum(memAddress)); + /* Record key and ID in lockfile for data directory. */ + RecordSharedMemoryInLockFile(memKey, shmid); + return memAddress; } @@ -660,6 +663,41 @@ IpcMemoryDelete(int status, Datum shmId) */ } +/****************************************************************************/ +/* SharedMemoryIsInUse(shmKey, shmId) Is a shared memory segment in use? */ +/****************************************************************************/ +bool +SharedMemoryIsInUse(IpcMemoryKey shmKey, IpcMemoryId shmId) +{ + struct shmid_ds shmStat; + + /* + * 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) + { + /* + * EINVAL actually has multiple possible causes documented in the + * shmctl man page, but we assume it must mean the segment no longer + * exists. + */ + if (errno == EINVAL) + return false; + /* Else assume segment is in use */ + return true; + } + /* If it has attached processes, it's in use */ + if (shmStat.shm_nattch != 0) + return true; + return false; +} + + /* ---------------------------------------------------------------- * private memory support * |