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

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.

1 files changed, 7 insertions, 64 deletions

diff --git a/src/include/storage/ipc.h b/src/include/storage/ipc.h
index 6a96ea2d125..5ebee36b9f7 100644
--- a/src/include/storage/ipc.h
+++ b/src/include/storage/ipc.h
@@ -3,63 +3,21 @@
  * ipc.h
  *	  POSTGRES inter-process communication definitions.
  *
+ * This file is misnamed, as it no longer has much of anything directly
+ * to do with IPC.  The functionality here is concerned with managing
+ * exit-time cleanup for either a postmaster or a backend.
+ *
  *
  * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Id: ipc.h,v 1.54 2001/11/05 17:46:35 momjian Exp $
+ * $Id: ipc.h,v 1.55 2002/05/05 00:03:29 tgl Exp $
  *
- * Some files that would normally need to include only sys/ipc.h must
- * instead include this file because on Ultrix, sys/ipc.h is not designed
- * to be included multiple times.  This file (by virtue of the ifndef IPC_H)
- * is.
  *-------------------------------------------------------------------------
  */
 #ifndef IPC_H
 #define IPC_H
 
-#include <sys/types.h>
-#ifdef HAVE_SYS_IPC_H
-#include <sys/ipc.h>
-#endif   /* HAVE_SYS_IPC_H */
-
-#ifndef HAVE_UNION_SEMUN
-union semun
-{
-	int			val;
-	struct semid_ds *buf;
-	unsigned short *array;
-};
-#endif
-
-
-/* generic IPC definitions */
-
-#define IPCProtection	(0600)	/* access/modify by user only */
-
-/* semaphore definitions */
-
-typedef uint32 IpcSemaphoreKey; /* semaphore key passed to semget(2) */
-typedef int IpcSemaphoreId;		/* semaphore ID returned by semget(2) */
-
-#define IPC_NMAXSEM		32		/* maximum number of semaphores per semID */
-
-#define PGSemaMagic  537		/* must be less than SEMVMX */
-
-/* shared memory definitions */
-
-typedef uint32 IpcMemoryKey;	/* shared memory key passed to shmget(2) */
-typedef int IpcMemoryId;		/* shared memory ID returned by shmget(2) */
-
-typedef struct PGShmemHeader	/* standard header for all Postgres shmem */
-{
-	int32		magic;			/* magic # to identify Postgres segments */
-#define PGShmemMagic  679834892
-	pid_t		creatorPID;		/* PID of creating process */
-	uint32		totalsize;		/* total size of segment */
-	uint32		freeoffset;		/* offset to first free space */
-} PGShmemHeader;
-
 
 /* ipc.c */
 extern bool proc_exit_inprogress;
@@ -70,24 +28,9 @@ extern void on_proc_exit(void (*function) (), Datum arg);
 extern void on_shmem_exit(void (*function) (), Datum arg);
 extern void on_exit_reset(void);
 
-extern void IpcInitKeyAssignment(int port);
-
-extern IpcSemaphoreId IpcSemaphoreCreate(int numSems, int permission,
-				   int semStartValue,
-				   bool removeOnExit);
-extern void IpcSemaphoreKill(IpcSemaphoreId semId);
-extern void IpcSemaphoreLock(IpcSemaphoreId semId, int sem, bool interruptOK);
-extern void IpcSemaphoreUnlock(IpcSemaphoreId semId, int sem);
-extern bool IpcSemaphoreTryLock(IpcSemaphoreId semId, int sem);
-extern int	IpcSemaphoreGetValue(IpcSemaphoreId semId, int sem);
-
-extern PGShmemHeader *IpcMemoryCreate(uint32 size, bool makePrivate,
-				int permission);
-
-extern bool SharedMemoryIsInUse(IpcMemoryKey shmKey, IpcMemoryId shmId);
-
 /* ipci.c */
 extern void CreateSharedMemoryAndSemaphores(bool makePrivate,
-								int maxBackends);
+											int maxBackends,
+											int port);
 
 #endif   /* IPC_H */