Index: src/backend/port/sysv_shmem.c
===================================================================
RCS file: /cvsroot/pgsql-server/src/backend/port/sysv_shmem.c,v
retrieving revision 1.9
diff -c -c -r1.9 sysv_shmem.c
*** src/backend/port/sysv_shmem.c	8 May 2003 14:49:03 -0000	1.9
--- src/backend/port/sysv_shmem.c	8 May 2003 19:00:12 -0000
***************
*** 47,52 ****
--- 47,54 ----
  static void IpcMemoryDelete(int status, Datum shmId);
  static void *PrivateMemoryCreate(uint32 size);
  static void PrivateMemoryDelete(int status, Datum memaddr);
+ static PGShmemHeader *PGSharedMemoryAttach(IpcMemoryKey key,
+ 										IpcMemoryId *shmid, void *addr);
  
  
  /*
***************
*** 297,368 ****
  	IpcMemoryKey NextShmemSegID;
  	void	   *memAddress;
  	PGShmemHeader *hdr;
  
  	/* Room for a header? */
  	Assert(size > MAXALIGN(sizeof(PGShmemHeader)));
  
! 	if (ExecBackend && UsedShmemSegID != 0)
! 		NextShmemSegID = UsedShmemSegID;
! 	else
! 		NextShmemSegID = port * 1000 + 1;
! 
! 	for (;;NextShmemSegID++)
  	{
! 		IpcMemoryId shmid;
! 
! 		/* Special case if creating a private segment --- just malloc() it */
! 		if (makePrivate)
  		{
! 			memAddress = PrivateMemoryCreate(size);
! 			break;
! 		}
! 
! 		/* If attach to fixed address, only try once */
! 		if (ExecBackend && UsedShmemSegAddr != NULL && NextShmemSegID != UsedShmemSegID)
! 		{
! 			fprintf(stderr, "Unable to attach to memory at fixed address: shmget(key=%d, addr=%p) failed: %s\n",
  				(int) UsedShmemSegID, UsedShmemSegAddr, strerror(errno));
  			proc_exit(1);
  		}
  
! 		if (!ExecBackend || UsedShmemSegAddr == NULL)
! 		{
! 			/* 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 */
! 
! 		/* use intimate shared memory on SPARC Solaris */
! 		memAddress = shmat(shmid, UsedShmemSegAddr,
! #if defined(solaris) && defined(__sparc__)
! 				SHM_SHARE_MMU
! #else
! 				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 */
  		}
  
! 		/* Successfully attached to shared memory, which is all we wanted */
! 		if (ExecBackend && UsedShmemSegAddr != NULL)
! 			break;
  
  		/* Check shared memory and possibly remove and recreate */
  			
  		/*
  		 * If I am not the creator and it belongs to an extant process,
  		 * continue.
--- 299,346 ----
  	IpcMemoryKey NextShmemSegID;
  	void	   *memAddress;
  	PGShmemHeader *hdr;
+ 	IpcMemoryId shmid;
  
  	/* Room for a header? */
  	Assert(size > MAXALIGN(sizeof(PGShmemHeader)));
  
! 	/* Just attach and return the pointer */
! 	if (ExecBackend && UsedShmemSegAddr != NULL && !makePrivate)
  	{
! 		if ((hdr = (PGShmemHeader *) memAddress = PGSharedMemoryAttach(
! 						UsedShmemSegID, &shmid, UsedShmemSegAddr)) == NULL)
  		{
! 			fprintf(stderr, "Unable to attach to proper memory at fixed address: shmget(key=%d, addr=%p) failed: %s\n",
  				(int) UsedShmemSegID, UsedShmemSegAddr, strerror(errno));
  			proc_exit(1);
  		}
+ 		return hdr;
+ 	}
  
! 	/* Create shared memory */
! 	
! 	NextShmemSegID = port * 1000 + 1;
  
! 	for (;;NextShmemSegID++)
! 	{
! 		/* 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 */
  
  		/* Check shared memory and possibly remove and recreate */
  			
+ 		if ((hdr = (PGShmemHeader *) memAddress = PGSharedMemoryAttach(
+ 						NextShmemSegID, &shmid, UsedShmemSegAddr)) == NULL)
+ 			continue;			/* can't attach, not one of mine */
+ 
  		/*
  		 * If I am not the creator and it belongs to an extant process,
  		 * continue.
***************
*** 401,431 ****
  		 */
  	}
  
  	hdr = (PGShmemHeader *) memAddress;
  
! 	if (!ExecBackend || makePrivate || UsedShmemSegAddr == NULL)
! 	{
! 		/*
! 		 * 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->creatorPID = getpid();
! 		hdr->magic = PGShmemMagic;
! 	
! 		/*
! 		 * Initialize space allocation status for segment.
! 		 */
! 		hdr->totalsize = size;
! 		hdr->freeoffset = MAXALIGN(sizeof(PGShmemHeader));
! 	}
  
! 	if (ExecBackend && !makePrivate && UsedShmemSegAddr == NULL)
  	{
  		UsedShmemSegAddr = memAddress;
  		UsedShmemSegID = NextShmemSegID;
  	}
  
  	return hdr;
  }
--- 379,438 ----
  		 */
  	}
  
+ 	/*
+ 	 * 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));
  
! 	
! 	if (ExecBackend && UsedShmemSegAddr == NULL && !makePrivate)
  	{
  		UsedShmemSegAddr = memAddress;
  		UsedShmemSegID = NextShmemSegID;
  	}
+ 	
+ 	return hdr;
+ }
+ 
+ 
+ /*
+  *	Attach to shared memory and make sure it has a Postgres header
+  */
+ static PGShmemHeader *
+ PGSharedMemoryAttach(IpcMemoryKey key, IpcMemoryId *shmid, void *addr)
+ {
+ 	PGShmemHeader *hdr;
+ 
+ 	if ((*shmid = shmget(key, sizeof(PGShmemHeader), 0)) < 0)
+ 		return NULL;
  
+ 	hdr = (PGShmemHeader *) shmat(*shmid, UsedShmemSegAddr,
+ #if defined(solaris) && defined(__sparc__)
+ 			/* use intimate shared memory on SPARC Solaris */
+ 			SHM_SHARE_MMU
+ #else
+ 			0
+ #endif
+ 		);
+ 
+ 	if (hdr == (PGShmemHeader *) -1)
+ 		return NULL;			/* failed: must be some other app's */
+ 
+ 	if (hdr->magic != PGShmemMagic)
+ 	{
+ 		shmdt(hdr);
+ 		return NULL;			/* segment belongs to a non-Postgres app */
+ 	}
  	return hdr;
  }