diff options
Diffstat (limited to 'src/backend/port/sysv_shmem.c')
| -rw-r--r-- | src/backend/port/sysv_shmem.c | 75 |
1 files changed, 45 insertions, 30 deletions
diff --git a/src/backend/port/sysv_shmem.c b/src/backend/port/sysv_shmem.c index 3c3f928ca2d..63ff4ad57ef 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 - * $PostgreSQL: pgsql/src/backend/port/sysv_shmem.c,v 1.40 2004/11/09 21:30:13 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/port/sysv_shmem.c,v 1.41 2004/12/29 21:35:58 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -142,11 +142,7 @@ InternalIpcMemoryCreate(IpcMemoryKey memKey, uint32 size) on_shmem_exit(IpcMemoryDelete, Int32GetDatum(shmid)); /* OK, should be able to attach to the segment */ -#ifdef EXEC_BACKEND - memAddress = shmat(shmid, UsedShmemSegAddr, PG_SHMAT_FLAGS); -#else memAddress = shmat(shmid, NULL, PG_SHMAT_FLAGS); -#endif if (memAddress == (void *) -1) elog(FATAL, "shmat(id=%d) failed: %m", shmid); @@ -279,7 +275,7 @@ PGSharedMemoryIsInUse(unsigned long id1, unsigned long id2) * * Create a shared memory segment of the given size and initialize its * standard header. Also, register an on_shmem_exit callback to release - * the storage. For an exec'ed backend, it just attaches. + * the storage. * * Dead Postgres segments are recycled if found, but we do not fail upon * collision with non-Postgres shmem segments. The idea here is to detect and @@ -303,30 +299,6 @@ PGSharedMemoryCreate(uint32 size, bool makePrivate, int port) struct stat statbuf; #endif -#ifdef EXEC_BACKEND - /* If Exec case, just attach and return the pointer */ - if (UsedShmemSegAddr != NULL && !makePrivate && IsUnderPostmaster) - { - void *origUsedShmemSegAddr = UsedShmemSegAddr; - -#ifdef __CYGWIN__ - /* cygipc (currently) appears to not detach on exec. */ - PGSharedMemoryDetach(); - UsedShmemSegAddr = origUsedShmemSegAddr; -#endif - elog(DEBUG3, "Attaching to %p", UsedShmemSegAddr); - hdr = PGSharedMemoryAttach((IpcMemoryKey) UsedShmemSegID, &shmid); - if (hdr == NULL) - elog(FATAL, "could not attach to proper memory at fixed address: shmget(key=%d, addr=%p) failed: %m", - (int) UsedShmemSegID, UsedShmemSegAddr); - if (hdr != origUsedShmemSegAddr) - elog(FATAL, "attaching to shared mem returned unexpected address (got %p, expected %p)", - hdr, UsedShmemSegAddr); - UsedShmemSegAddr = hdr; - return hdr; - } -#endif - /* Room for a header? */ Assert(size > MAXALIGN(sizeof(PGShmemHeader))); @@ -424,6 +396,49 @@ PGSharedMemoryCreate(uint32 size, bool makePrivate, int port) return hdr; } +#ifdef EXEC_BACKEND + +/* + * PGSharedMemoryReAttach + * + * Re-attach to an already existing shared memory segment. In the non + * EXEC_BACKEND case this is not used, because postmaster children inherit + * the shared memory segment attachment via fork(). + * + * UsedShmemSegID and UsedShmemSegAddr are implicit parameters to this + * routine. The caller must have already restored them to the postmaster's + * values. + */ +void +PGSharedMemoryReAttach(void) +{ + IpcMemoryId shmid; + void *hdr; + void *origUsedShmemSegAddr = UsedShmemSegAddr; + + Assert(UsedShmemSegAddr != NULL); + Assert(IsUnderPostmaster); + +#ifdef __CYGWIN__ + /* cygipc (currently) appears to not detach on exec. */ + PGSharedMemoryDetach(); + UsedShmemSegAddr = origUsedShmemSegAddr; +#endif + + elog(DEBUG3, "Attaching to %p", UsedShmemSegAddr); + hdr = (void *) PGSharedMemoryAttach((IpcMemoryKey) UsedShmemSegID, &shmid); + if (hdr == NULL) + elog(FATAL, "could not reattach to shared memory (key=%d, addr=%p): %m", + (int) UsedShmemSegID, UsedShmemSegAddr); + if (hdr != origUsedShmemSegAddr) + elog(FATAL, "reattaching to shared memory returned unexpected address (got %p, expected %p)", + hdr, origUsedShmemSegAddr); + + UsedShmemSegAddr = hdr; /* probably redundant */ +} + +#endif /* EXEC_BACKEND */ + /* * PGSharedMemoryDetach * |