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Create an internal semaphore API that is not tied to SysV semaphores.

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As proof of concept, provide an alternate implementation based on POSIX
semaphores.  Also push the SysV shared-memory implementation into a
separate file so that it can be replaced conveniently.
This commit is contained in:
Tom Lane
2002-05-05 00:03:29 +00:00
parent 91fc10fdac
commit 72a3902a66
37 changed files with 1659 additions and 1370 deletions
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26
src/backend/utils/init/miscinit.c
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@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/utils/init/miscinit.c,v 1.88 2002/05/03 20:43:30 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/utils/init/miscinit.c,v 1.89 2002/05/05 00:03:29 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -32,6 +32,8 @@
#include "catalog/pg_shadow.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "storage/ipc.h"
#include "storage/pg_shmem.h"
#include "utils/builtins.h"
#include "utils/guc.h"
#include "utils/lsyscache.h"
@ -819,25 +821,24 @@ CreateLockFile(const char *filename, bool amPostmaster,
if (isDDLock)
{
char *ptr;
unsigned long shmKey,
shmId;
unsigned long id1,
id2;
ptr = strchr(buffer, '\n');
if (ptr != NULL &&
(ptr = strchr(ptr + 1, '\n')) != NULL)
{
ptr++;
if (sscanf(ptr, "%lu %lu", &shmKey, &shmId) == 2)
if (sscanf(ptr, "%lu %lu", &id1, &id2) == 2)
{
if (SharedMemoryIsInUse((IpcMemoryKey) shmKey,
(IpcMemoryId) shmId))
if (PGSharedMemoryIsInUse(id1, id2))
{
fprintf(stderr,
"Found a pre-existing shared memory block (ID %d) still in use.\n"
"Found a pre-existing shared memory block (key %lu, id %lu) still in use.\n"
"If you're sure there are no old backends still running,\n"
"remove the shared memory block with ipcrm(1), or just\n"
"delete \"%s\".\n",
(int) shmId, filename);
id1, id2, filename);
return false;
}
}
@ -941,11 +942,11 @@ TouchSocketLockFile(void)
* This may be called multiple times in the life of a postmaster, if we
* delete and recreate shmem due to backend crash. Therefore, be prepared
* to overwrite existing information. (As of 7.1, a postmaster only creates
* one shm seg anyway; but for the purposes here, if we did have more than
* one shm seg at a time; but for the purposes here, if we did have more than
* one then any one of them would do anyway.)
*/
void
RecordSharedMemoryInLockFile(IpcMemoryKey shmKey, IpcMemoryId shmId)
RecordSharedMemoryInLockFile(unsigned long id1, unsigned long id2)
{
int fd;
int len;
@ -988,11 +989,10 @@ RecordSharedMemoryInLockFile(IpcMemoryKey shmKey, IpcMemoryId shmId)
ptr++;
/*
* Append shm key and ID. Format to try to keep it the same length
* Append key information. Format to try to keep it the same length
* always (trailing junk won't hurt, but might confuse humans).
*/
sprintf(ptr, "%9lu %9lu\n",
(unsigned long) shmKey, (unsigned long) shmId);
sprintf(ptr, "%9lu %9lu\n", id1, id2);
/*
* And rewrite the data. Since we write in a single kernel call, this