diff options
Diffstat (limited to 'src/backend/port/sysv_shmem.c')
| -rw-r--r-- | src/backend/port/sysv_shmem.c | 400 |
1 files changed, 0 insertions, 400 deletions
diff --git a/src/backend/port/sysv_shmem.c b/src/backend/port/sysv_shmem.c deleted file mode 100644 index 968b77af6ea..00000000000 --- a/src/backend/port/sysv_shmem.c +++ /dev/null @@ -1,400 +0,0 @@ -/*------------------------------------------------------------------------- - * - * sysv_shmem.c - * Implement shared memory using SysV facilities - * - * These routines represent a fairly thin layer on top of SysV shared - * memory functionality. - * - * Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group - * Portions Copyright (c) 1994, Regents of the University of California - * - * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/port/sysv_shmem.c,v 1.2 2002/06/20 20:29:33 momjian Exp $ - * - *------------------------------------------------------------------------- - */ -#include "postgres.h" - -#include <errno.h> -#include <signal.h> -#include <unistd.h> -#include <sys/file.h> -#include <sys/types.h> -#ifdef HAVE_SYS_IPC_H -#include <sys/ipc.h> -#endif -#ifdef HAVE_SYS_SHM_H -#include <sys/shm.h> -#endif -#ifdef HAVE_KERNEL_OS_H -#include <kernel/OS.h> -#endif - -#include "miscadmin.h" -#include "storage/ipc.h" -#include "storage/pg_shmem.h" - - -typedef uint32 IpcMemoryKey; /* shared memory key passed to shmget(2) */ -typedef int IpcMemoryId; /* shared memory ID returned by shmget(2) */ - -#define IPCProtection (0600) /* access/modify by user only */ - - -static void *InternalIpcMemoryCreate(IpcMemoryKey memKey, uint32 size); -static void IpcMemoryDetach(int status, Datum shmaddr); -static void IpcMemoryDelete(int status, Datum shmId); -static void *PrivateMemoryCreate(uint32 size); -static void PrivateMemoryDelete(int status, Datum memaddr); - - -/* - * InternalIpcMemoryCreate(memKey, size) - * - * Attempt to create a new shared memory segment with the specified key. - * Will fail (return NULL) if such a segment already exists. If successful, - * attach the segment to the current process and return its attached address. - * On success, callbacks are registered with on_shmem_exit to detach and - * delete the segment when on_shmem_exit is called. - * - * If we fail with a failure code other than collision-with-existing-segment, - * print out an error and abort. Other types of errors are not recoverable. - */ -static void * -InternalIpcMemoryCreate(IpcMemoryKey memKey, uint32 size) -{ - IpcMemoryId shmid; - void *memAddress; - - shmid = shmget(memKey, size, IPC_CREAT | IPC_EXCL | IPCProtection); - - 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. - */ - if (errno == EEXIST || errno == EACCES -#ifdef EIDRM - || errno == EIDRM -#endif - ) - return NULL; - - /* - * Else complain and abort - */ - fprintf(stderr, "IpcMemoryCreate: shmget(key=%d, size=%u, 0%o) failed: %s\n", - (int) memKey, size, (IPC_CREAT | IPC_EXCL | IPCProtection), - strerror(errno)); - - if (errno == EINVAL) - fprintf(stderr, - "\nThis error usually means that PostgreSQL's request for a shared memory\n" - "segment exceeded your kernel's SHMMAX parameter. You can either\n" - "reduce the request size or reconfigure the kernel with larger SHMMAX.\n" - "To reduce the request size (currently %u bytes), reduce\n" - "PostgreSQL's shared_buffers parameter (currently %d) and/or\n" - "its max_connections parameter (currently %d).\n" - "\n" - "If the request size is already small, it's possible that it is less than\n" - "your kernel's SHMMIN parameter, in which case raising the request size or\n" - "reconfiguring SHMMIN is called for.\n" - "\n" - "The PostgreSQL Administrator's Guide contains more information about\n" - "shared memory configuration.\n\n", - size, NBuffers, MaxBackends); - - else if (errno == ENOMEM) - fprintf(stderr, - "\nThis error usually means that PostgreSQL's request for a shared\n" - "memory segment exceeded available memory or swap space.\n" - "To reduce the request size (currently %u bytes), reduce\n" - "PostgreSQL's shared_buffers parameter (currently %d) and/or\n" - "its max_connections parameter (currently %d).\n" - "\n" - "The PostgreSQL Administrator's Guide contains more information about\n" - "shared memory configuration.\n\n", - size, NBuffers, MaxBackends); - - else if (errno == ENOSPC) - fprintf(stderr, - "\nThis error does *not* mean that you have run out of disk space.\n" - "\n" - "It occurs either if all available shared memory IDs have been taken,\n" - "in which case you need to raise the SHMMNI parameter in your kernel,\n" - "or because the system's overall limit for shared memory has been\n" - "reached. If you cannot increase the shared memory limit,\n" - "reduce PostgreSQL's shared memory request (currently %u bytes),\n" - "by reducing its shared_buffers parameter (currently %d) and/or\n" - "its max_connections parameter (currently %d).\n" - "\n" - "The PostgreSQL Administrator's Guide contains more information about\n" - "shared memory configuration.\n\n", - size, NBuffers, MaxBackends); - - proc_exit(1); - } - - /* Register on-exit routine to delete the new segment */ - on_shmem_exit(IpcMemoryDelete, Int32GetDatum(shmid)); - - /* OK, should be able to attach to the segment */ -#if defined(solaris) && defined(__sparc__) - /* use intimate shared memory on SPARC Solaris */ - memAddress = shmat(shmid, 0, SHM_SHARE_MMU); -#else - memAddress = shmat(shmid, 0, 0); -#endif - - if (memAddress == (void *) -1) - { - fprintf(stderr, "IpcMemoryCreate: shmat(id=%d) failed: %s\n", - shmid, strerror(errno)); - proc_exit(1); - } - - /* 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((unsigned long) memKey, - (unsigned long) shmid); - - return memAddress; -} - -/****************************************************************************/ -/* IpcMemoryDetach(status, shmaddr) removes a shared memory segment */ -/* from process' address spaceq */ -/* (called as an on_shmem_exit callback, hence funny argument list) */ -/****************************************************************************/ -static void -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(WARNING), but that's pretty - * pointless considering any client has long since disconnected ... - */ -} - -/****************************************************************************/ -/* IpcMemoryDelete(status, shmId) deletes a shared memory segment */ -/* (called as an on_shmem_exit callback, hence funny argument list) */ -/****************************************************************************/ -static void -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(WARNING), but that's pretty - * pointless considering any client has long since disconnected ... - */ -} - -/* - * PGSharedMemoryIsInUse - * - * Is a previously-existing shmem segment still existing and in use? - */ -bool -PGSharedMemoryIsInUse(unsigned long id1, unsigned long id2) -{ - IpcMemoryId shmId = (IpcMemoryId) id2; - 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 - * - * Rather than allocating shmem segments with IPC_PRIVATE key, we - * just malloc() the requested amount of space. This code emulates - * the needed shmem functions. - * ---------------------------------------------------------------- - */ - -static void * -PrivateMemoryCreate(uint32 size) -{ - void *memAddress; - - memAddress = malloc(size); - if (!memAddress) - { - fprintf(stderr, "PrivateMemoryCreate: malloc(%u) failed\n", size); - proc_exit(1); - } - MemSet(memAddress, 0, size); /* keep Purify quiet */ - - /* Register on-exit routine to release storage */ - on_shmem_exit(PrivateMemoryDelete, PointerGetDatum(memAddress)); - - return memAddress; -} - -static void -PrivateMemoryDelete(int status, Datum memaddr) -{ - free(DatumGetPointer(memaddr)); -} - - -/* - * PGSharedMemoryCreate - * - * 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. - * - * 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 - * re-use keys that may have been assigned by a crashed postmaster or backend. - * - * The port number is passed for possible use as a key (for SysV, we use - * it to generate the starting shmem key). In a standalone backend, - * zero will be passed. - */ -PGShmemHeader * -PGSharedMemoryCreate(uint32 size, bool makePrivate, int port) -{ - IpcMemoryKey NextShmemSegID; - void *memAddress; - PGShmemHeader *hdr; - - /* Room for a header? */ - Assert(size > MAXALIGN(sizeof(PGShmemHeader))); - - /* Loop till we find a free IPC key */ - NextShmemSegID = port * 1000; - - for (NextShmemSegID++;; NextShmemSegID++) - { - IpcMemoryId shmid; - - /* Special case if creating a private segment --- just malloc() it */ - if (makePrivate) - { - memAddress = PrivateMemoryCreate(size); - break; - } - - /* Try to create new segment */ - memAddress = InternalIpcMemoryCreate(NextShmemSegID, size); - if (memAddress) - break; /* successful create and attach */ - - /* See if it looks to be leftover from a dead Postgres process */ - shmid = shmget(NextShmemSegID, sizeof(PGShmemHeader), 0); - if (shmid < 0) - continue; /* failed: must be some other app's */ - -#if defined(solaris) && defined(__sparc__) - /* use intimate shared memory on SPARC Solaris */ - memAddress = shmat(shmid, 0, SHM_SHARE_MMU); -#else - memAddress = shmat(shmid, 0, 0); -#endif - - if (memAddress == (void *) -1) - continue; /* failed: must be some other app's */ - hdr = (PGShmemHeader *) memAddress; - if (hdr->magic != PGShmemMagic) - { - 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. - */ - if (hdr->creatorPID != getpid()) - { - if (kill(hdr->creatorPID, 0) == 0 || - errno != ESRCH) - { - shmdt(memAddress); - 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. - */ - shmdt(memAddress); - if (shmctl(shmid, IPC_RMID, (struct shmid_ds *) NULL) < 0) - continue; - - /* - * Now try again to create the segment. - */ - memAddress = InternalIpcMemoryCreate(NextShmemSegID, size); - 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. - */ - } - - /* - * OK, we created a new segment. Mark it as created by this process. - * The order of assignments here is critical so that another Postgres - * process can't see the header as valid but belonging to an invalid - * PID! - */ - hdr = (PGShmemHeader *) memAddress; - hdr->creatorPID = getpid(); - hdr->magic = PGShmemMagic; - - /* - * Initialize space allocation status for segment. - */ - hdr->totalsize = size; - hdr->freeoffset = MAXALIGN(sizeof(PGShmemHeader)); - - return hdr; -} |