diff options
Diffstat (limited to 'src/backend/storage/ipc/ipc.c')
| -rw-r--r-- | src/backend/storage/ipc/ipc.c | 153 |
1 files changed, 90 insertions, 63 deletions
diff --git a/src/backend/storage/ipc/ipc.c b/src/backend/storage/ipc/ipc.c index eb8d488bdd3..375376abf83 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 1.63 2001/03/13 01:17:06 tgl Exp $ + * $Header: /cvsroot/pgsql/src/backend/storage/ipc/ipc.c,v 1.64 2001/03/22 03:59:45 momjian Exp $ * * NOTES * @@ -71,7 +71,7 @@ static IpcSemaphoreId InternalIpcSemaphoreCreate(IpcSemaphoreKey semKey, int semStartValue, bool removeOnExit); static void CallbackSemaphoreKill(int status, Datum semId); static void *InternalIpcMemoryCreate(IpcMemoryKey memKey, uint32 size, - int permission); + int permission); static void IpcMemoryDetach(int status, Datum shmaddr); static void IpcMemoryDelete(int status, Datum shmId); static void *PrivateMemoryCreate(uint32 size); @@ -101,6 +101,7 @@ static struct ONEXIT void (*function) (); Datum arg; } on_proc_exit_list[MAX_ON_EXITS], + on_shmem_exit_list[MAX_ON_EXITS]; static int on_proc_exit_index, @@ -127,9 +128,9 @@ proc_exit(int code) proc_exit_inprogress = true; /* - * Forget any pending cancel or die requests; we're doing our best - * to close up shop already. Note that the signal handlers will not - * set these flags again, now that proc_exit_inprogress is set. + * Forget any pending cancel or die requests; we're doing our best to + * close up shop already. Note that the signal handlers will not set + * these flags again, now that proc_exit_inprogress is set. */ InterruptPending = false; ProcDiePending = false; @@ -198,7 +199,7 @@ shmem_exit(int code) * ---------------------------------------------------------------- */ void -on_proc_exit(void (*function) (), Datum arg) + on_proc_exit(void (*function) (), Datum arg) { if (on_proc_exit_index >= MAX_ON_EXITS) elog(FATAL, "Out of on_proc_exit slots"); @@ -217,7 +218,7 @@ on_proc_exit(void (*function) (), Datum arg) * ---------------------------------------------------------------- */ void -on_shmem_exit(void (*function) (), Datum arg) + on_shmem_exit(void (*function) (), Datum arg) { if (on_shmem_exit_index >= MAX_ON_EXITS) elog(FATAL, "Out of on_shmem_exit slots"); @@ -282,11 +283,13 @@ InternalIpcSemaphoreCreate(IpcSemaphoreKey semKey, if (semId < 0) { + /* * Fail quietly if error indicates a collision with existing set. - * One would expect EEXIST, given that we said IPC_EXCL, but perhaps - * we could get a permission violation instead? Also, EIDRM might - * occur if an old set is slated for destruction but not gone yet. + * One would expect EEXIST, given that we said IPC_EXCL, but + * perhaps we could get a permission violation instead? Also, + * EIDRM might occur if an old set is slated for destruction but + * not gone yet. */ if (errno == EEXIST || errno == EACCES #ifdef EIDRM @@ -294,11 +297,12 @@ InternalIpcSemaphoreCreate(IpcSemaphoreKey semKey, #endif ) return -1; + /* * Else complain and abort */ fprintf(stderr, "IpcSemaphoreCreate: semget(key=%d, num=%d, 0%o) failed: %s\n", - (int) semKey, numSems, (IPC_CREAT|IPC_EXCL|permission), + (int) semKey, numSems, (IPC_CREAT | IPC_EXCL | permission), strerror(errno)); if (errno == ENOSPC) @@ -325,7 +329,7 @@ InternalIpcSemaphoreCreate(IpcSemaphoreKey semKey, if (errno == ERANGE) fprintf(stderr, "You possibly need to raise your kernel's SEMVMX value to be at least\n" - "%d. Look into the PostgreSQL documentation for details.\n", + "%d. Look into the PostgreSQL documentation for details.\n", semStartValue); IpcSemaphoreKill(semId); @@ -348,12 +352,14 @@ IpcSemaphoreKill(IpcSemaphoreId semId) { union semun semun; - semun.val = 0; /* unused, but keep compiler quiet */ + semun.val = 0; /* unused, but keep compiler quiet */ if (semctl(semId, 0, IPC_RMID, semun) < 0) fprintf(stderr, "IpcSemaphoreKill: semctl(%d, 0, IPC_RMID, ...) failed: %s\n", semId, strerror(errno)); - /* We used to report a failure via elog(NOTICE), but that's pretty + + /* + * We used to report a failure via elog(NOTICE), but that's pretty * pointless considering any client has long since disconnected ... */ } @@ -393,13 +399,13 @@ IpcSemaphoreLock(IpcSemaphoreId semId, int sem, bool interruptOK) * section already). * * Once we acquire the lock, we do NOT check for an interrupt before - * returning. The caller needs to be able to record ownership of + * returning. The caller needs to be able to record ownership of * the lock before any interrupt can be accepted. * * There is a window of a few instructions between CHECK_FOR_INTERRUPTS - * and entering the semop() call. If a cancel/die interrupt occurs in + * and entering the semop() call. If a cancel/die interrupt occurs in * that window, we would fail to notice it until after we acquire the - * lock (or get another interrupt to escape the semop()). We can avoid + * lock (or get another interrupt to escape the semop()). We can avoid * this problem by temporarily setting ImmediateInterruptOK = true * before we do CHECK_FOR_INTERRUPTS; then, a die() interrupt in this * interval will execute directly. However, there is a huge pitfall: @@ -426,7 +432,7 @@ IpcSemaphoreLock(IpcSemaphoreId semId, int sem, bool interruptOK) if (errStatus == -1) { - fprintf(stderr, "IpcSemaphoreLock: semop(id=%d) failed: %s\n", + fprintf(stderr, "IpcSemaphoreLock: semop(id=%d) failed: %s\n", semId, strerror(errno)); proc_exit(255); } @@ -503,7 +509,7 @@ IpcSemaphoreTryLock(IpcSemaphoreId semId, int sem) return false; /* failed to lock it */ #endif /* Otherwise we got trouble */ - fprintf(stderr, "IpcSemaphoreTryLock: semop(id=%d) failed: %s\n", + fprintf(stderr, "IpcSemaphoreTryLock: semop(id=%d) failed: %s\n", semId, strerror(errno)); proc_exit(255); } @@ -516,7 +522,8 @@ int IpcSemaphoreGetValue(IpcSemaphoreId semId, int sem) { union semun dummy; /* for Solaris */ - dummy.val = 0; /* unused */ + + dummy.val = 0; /* unused */ return semctl(semId, sem, GETVAL, dummy); } @@ -526,7 +533,8 @@ static pid_t IpcSemaphoreGetLastPID(IpcSemaphoreId semId, int sem) { union semun dummy; /* for Solaris */ - dummy.val = 0; /* unused */ + + dummy.val = 0; /* unused */ return semctl(semId, sem, GETPID, dummy); } @@ -563,11 +571,13 @@ InternalIpcMemoryCreate(IpcMemoryKey memKey, uint32 size, int permission) if (shmid < 0) { + /* - * Fail quietly if error indicates a collision with existing segment. - * One would expect EEXIST, given that we said IPC_EXCL, but perhaps - * we could get a permission violation instead? Also, EIDRM might - * occur if an old seg is slated for destruction but not gone yet. + * Fail quietly if error indicates a collision with existing + * segment. One would expect EEXIST, given that we said IPC_EXCL, + * but perhaps we could get a permission violation instead? Also, + * EIDRM might occur if an old seg is slated for destruction but + * not gone yet. */ if (errno == EEXIST || errno == EACCES #ifdef EIDRM @@ -575,6 +585,7 @@ InternalIpcMemoryCreate(IpcMemoryKey memKey, uint32 size, int permission) #endif ) return NULL; + /* * Else complain and abort */ @@ -584,7 +595,7 @@ InternalIpcMemoryCreate(IpcMemoryKey memKey, uint32 size, int permission) if (errno == EINVAL) fprintf(stderr, - "\nThis error can be caused by one of three things:\n\n" + "\nThis error can be caused by one of three things:\n\n" "1. The maximum size for shared memory segments on your system was\n" " exceeded. You need to raise the SHMMAX parameter in your kernel\n" " to be at least %u bytes.\n\n" @@ -618,7 +629,7 @@ InternalIpcMemoryCreate(IpcMemoryKey memKey, uint32 size, int permission) if (memAddress == (void *) -1) { - fprintf(stderr, "IpcMemoryCreate: shmat(id=%d) failed: %s\n", + fprintf(stderr, "IpcMemoryCreate: shmat(id=%d) failed: %s\n", shmid, strerror(errno)); proc_exit(1); } @@ -643,7 +654,9 @@ IpcMemoryDetach(int status, Datum shmaddr) if (shmdt(DatumGetPointer(shmaddr)) < 0) fprintf(stderr, "IpcMemoryDetach: shmdt(%p) failed: %s\n", DatumGetPointer(shmaddr), strerror(errno)); - /* We used to report a failure via elog(NOTICE), but that's pretty + + /* + * We used to report a failure via elog(NOTICE), but that's pretty * pointless considering any client has long since disconnected ... */ } @@ -658,7 +671,9 @@ IpcMemoryDelete(int status, Datum shmId) if (shmctl(DatumGetInt32(shmId), IPC_RMID, (struct shmid_ds *) NULL) < 0) fprintf(stderr, "IpcMemoryDelete: shmctl(%d, %d, 0) failed: %s\n", DatumGetInt32(shmId), IPC_RMID, strerror(errno)); - /* We used to report a failure via elog(NOTICE), but that's pretty + + /* + * We used to report a failure via elog(NOTICE), but that's pretty * pointless considering any client has long since disconnected ... */ } @@ -669,22 +684,23 @@ IpcMemoryDelete(int status, Datum shmId) bool SharedMemoryIsInUse(IpcMemoryKey shmKey, IpcMemoryId shmId) { - struct shmid_ds shmStat; + 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. + * 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. + * 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. + * shmctl man page, but we assume it must mean the segment no + * longer exists. */ if (errno == EINVAL) return false; @@ -718,7 +734,7 @@ PrivateMemoryCreate(uint32 size) fprintf(stderr, "PrivateMemoryCreate: malloc(%u) failed\n", size); proc_exit(1); } - MemSet(memAddress, 0, size); /* keep Purify quiet */ + MemSet(memAddress, 0, size);/* keep Purify quiet */ /* Register on-exit routine to release storage */ on_shmem_exit(PrivateMemoryDelete, PointerGetDatum(memAddress)); @@ -763,14 +779,14 @@ IpcInitKeyAssignment(int port) PGShmemHeader * IpcMemoryCreate(uint32 size, bool makePrivate, int permission) { - void *memAddress; + void *memAddress; PGShmemHeader *hdr; /* Room for a header? */ Assert(size > MAXALIGN(sizeof(PGShmemHeader))); /* Loop till we find a free IPC key */ - for (NextShmemSegID++ ; ; NextShmemSegID++) + for (NextShmemSegID++;; NextShmemSegID++) { IpcMemoryId shmid; @@ -799,6 +815,7 @@ IpcMemoryCreate(uint32 size, bool makePrivate, int permission) shmdt(memAddress); continue; /* segment belongs to a non-Postgres app */ } + /* * If the creator PID is my own PID or does not belong to any * extant process, it's safe to zap it. @@ -812,28 +829,32 @@ IpcMemoryCreate(uint32 size, bool makePrivate, int permission) continue; /* segment belongs to a live process */ } } + /* - * The segment appears to be from a dead Postgres process, or - * from a previous cycle of life in this same process. Zap it, - * if possible. This probably shouldn't fail, but if it does, - * assume the segment belongs to someone else after all, - * and continue quietly. + * The segment appears to be from a dead Postgres process, or from + * a previous cycle of life in this same process. Zap it, if + * possible. This probably shouldn't fail, but if it does, assume + * the segment belongs to someone else after all, and continue + * quietly. */ shmdt(memAddress); if (shmctl(shmid, IPC_RMID, (struct shmid_ds *) NULL) < 0) continue; + /* * Now try again to create the segment. */ memAddress = InternalIpcMemoryCreate(NextShmemSegID, size, permission); if (memAddress) break; /* successful create and attach */ + /* * Can only get here if some other process managed to create the - * same shmem key before we did. Let him have that one, - * loop around to try next key. + * same shmem key before we did. Let him have that one, loop + * around to try next key. */ } + /* * OK, we created a new segment. Mark it as created by this process. * The order of assignments here is critical so that another Postgres @@ -843,6 +864,7 @@ IpcMemoryCreate(uint32 size, bool makePrivate, int permission) hdr = (PGShmemHeader *) memAddress; hdr->creatorPID = getpid(); hdr->magic = PGShmemMagic; + /* * Initialize space allocation status for segment. */ @@ -862,27 +884,28 @@ IpcSemaphoreId IpcSemaphoreCreate(int numSems, int permission, int semStartValue, bool removeOnExit) { - IpcSemaphoreId semId; + IpcSemaphoreId semId; union semun semun; /* Loop till we find a free IPC key */ - for (NextSemaID++ ; ; NextSemaID++) + for (NextSemaID++;; NextSemaID++) { - pid_t creatorPID; + pid_t creatorPID; /* Try to create new semaphore set */ - semId = InternalIpcSemaphoreCreate(NextSemaID, numSems+1, + semId = InternalIpcSemaphoreCreate(NextSemaID, numSems + 1, permission, semStartValue, removeOnExit); if (semId >= 0) break; /* successful create */ /* See if it looks to be leftover from a dead Postgres process */ - semId = semget(NextSemaID, numSems+1, 0); + semId = semget(NextSemaID, numSems + 1, 0); if (semId < 0) continue; /* failed: must be some other app's */ if (IpcSemaphoreGetValue(semId, numSems) != PGSemaMagic) continue; /* sema belongs to a non-Postgres app */ + /* * If the creator PID is my own PID or does not belong to any * extant process, it's safe to zap it. @@ -896,46 +919,50 @@ IpcSemaphoreCreate(int numSems, int permission, errno != ESRCH) continue; /* sema belongs to a live process */ } + /* * The sema set appears to be from a dead Postgres process, or - * from a previous cycle of life in this same process. Zap it, - * if possible. This probably shouldn't fail, but if it does, - * assume the sema set belongs to someone else after all, - * and continue quietly. + * from a previous cycle of life in this same process. Zap it, if + * possible. This probably shouldn't fail, but if it does, assume + * the sema set belongs to someone else after all, and continue + * quietly. */ semun.val = 0; /* unused, but keep compiler quiet */ if (semctl(semId, 0, IPC_RMID, semun) < 0) continue; + /* * Now try again to create the sema set. */ - semId = InternalIpcSemaphoreCreate(NextSemaID, numSems+1, + semId = InternalIpcSemaphoreCreate(NextSemaID, numSems + 1, permission, semStartValue, removeOnExit); if (semId >= 0) break; /* successful create */ + /* * Can only get here if some other process managed to create the - * same sema key before we did. Let him have that one, - * loop around to try next key. + * same sema key before we did. Let him have that one, loop + * around to try next key. */ } + /* * OK, we created a new sema set. Mark it as created by this process. * We do this by setting the spare semaphore to PGSemaMagic-1 and then - * incrementing it with semop(). That leaves it with value PGSemaMagic - * and sempid referencing this process. + * incrementing it with semop(). That leaves it with value + * PGSemaMagic and sempid referencing this process. */ - semun.val = PGSemaMagic-1; + semun.val = PGSemaMagic - 1; if (semctl(semId, numSems, SETVAL, semun) < 0) { fprintf(stderr, "IpcSemaphoreCreate: semctl(id=%d, %d, SETVAL, %d) failed: %s\n", - semId, numSems, PGSemaMagic-1, strerror(errno)); + semId, numSems, PGSemaMagic - 1, strerror(errno)); if (errno == ERANGE) fprintf(stderr, "You possibly need to raise your kernel's SEMVMX value to be at least\n" - "%d. Look into the PostgreSQL documentation for details.\n", + "%d. Look into the PostgreSQL documentation for details.\n", PGSemaMagic); proc_exit(1); |