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.

configure

@@ -15664,6 +15664,42 @@ HAVE_POSIX_SIGNALS=$pgac_cv_func_posix_signals
 
 
 
+# Select semaphore implementation type.
+if test x"$USE_NAMED_POSIX_SEMAPHORES" = x"1" ; then
+
+cat >>confdefs.h <<\_ACEOF
+#define USE_NAMED_POSIX_SEMAPHORES 1
+_ACEOF
+
+  SEMA_IMPLEMENTATION="src/backend/port/posix_sema.c"
+else
+  if test x"$USE_UNNAMED_POSIX_SEMAPHORES" = x"1" ; then
+
+cat >>confdefs.h <<\_ACEOF
+#define USE_UNNAMED_POSIX_SEMAPHORES 1
+_ACEOF
+
+    SEMA_IMPLEMENTATION="src/backend/port/posix_sema.c"
+  else
+
+cat >>confdefs.h <<\_ACEOF
+#define USE_SYSV_SEMAPHORES 1
+_ACEOF
+
+    SEMA_IMPLEMENTATION="src/backend/port/sysv_sema.c"
+  fi
+fi
+
+
+# Select shared-memory implementation type.
+
+cat >>confdefs.h <<\_ACEOF
+#define USE_SYSV_SHARED_MEMORY 1
+_ACEOF
+
+SHMEM_IMPLEMENTATION="src/backend/port/sysv_shmem.c"
+
+
 if test "$enable_nls" = yes ; then
 
   echo "$as_me:$LINENO: checking for library containing gettext" >&5
@@ -16724,7 +16760,7 @@ fi
 ac_config_files="$ac_config_files GNUmakefile src/Makefile.global"
 
 
-ac_config_links="$ac_config_links src/backend/port/dynloader.c:src/backend/port/dynloader/${template}.c src/include/dynloader.h:src/backend/port/dynloader/${template}.h src/include/pg_config_os.h:src/include/port/${template}.h src/Makefile.port:src/makefiles/Makefile.${template}"
+ac_config_links="$ac_config_links src/backend/port/dynloader.c:src/backend/port/dynloader/${template}.c src/backend/port/pg_sema.c:${SEMA_IMPLEMENTATION} src/backend/port/pg_shmem.c:${SHMEM_IMPLEMENTATION} src/include/dynloader.h:src/backend/port/dynloader/${template}.h src/include/pg_config_os.h:src/include/port/${template}.h src/Makefile.port:src/makefiles/Makefile.${template}"
 
 
 ac_config_headers="$ac_config_headers src/include/pg_config.h"
@@ -17207,6 +17243,8 @@ do
   "src/Makefile.global" ) CONFIG_FILES="$CONFIG_FILES src/Makefile.global" ;;
   "src/backend/port/tas.s" ) CONFIG_LINKS="$CONFIG_LINKS src/backend/port/tas.s:src/backend/port/tas/${tas_file}" ;;
   "src/backend/port/dynloader.c" ) CONFIG_LINKS="$CONFIG_LINKS src/backend/port/dynloader.c:src/backend/port/dynloader/${template}.c" ;;
+  "src/backend/port/pg_sema.c" ) CONFIG_LINKS="$CONFIG_LINKS src/backend/port/pg_sema.c:${SEMA_IMPLEMENTATION}" ;;
+  "src/backend/port/pg_shmem.c" ) CONFIG_LINKS="$CONFIG_LINKS src/backend/port/pg_shmem.c:${SHMEM_IMPLEMENTATION}" ;;
   "src/include/dynloader.h" ) CONFIG_LINKS="$CONFIG_LINKS src/include/dynloader.h:src/backend/port/dynloader/${template}.h" ;;
   "src/include/pg_config_os.h" ) CONFIG_LINKS="$CONFIG_LINKS src/include/pg_config_os.h:src/include/port/${template}.h" ;;
   "src/Makefile.port" ) CONFIG_LINKS="$CONFIG_LINKS src/Makefile.port:src/makefiles/Makefile.${template}" ;;

configure.in

 dnl Process this file with autoconf to produce a configure script.
-dnl $Header: /cvsroot/pgsql/configure.in,v 1.183 2002/04/26 19:47:35 tgl Exp $
+dnl $Header: /cvsroot/pgsql/configure.in,v 1.184 2002/05/05 00:03:28 tgl Exp $
 
 dnl Developers, please strive to achieve this order:
 dnl
@@ -1168,6 +1168,26 @@ AC_CHECK_TYPES([sig_atomic_t], [], [], [#include <signal.h>])
 PGAC_FUNC_POSIX_SIGNALS
 
 
+# Select semaphore implementation type.
+if test x"$USE_NAMED_POSIX_SEMAPHORES" = x"1" ; then
+  AC_DEFINE(USE_NAMED_POSIX_SEMAPHORES, 1, [Define to select named POSIX semaphores])
+  SEMA_IMPLEMENTATION="src/backend/port/posix_sema.c"
+else
+  if test x"$USE_UNNAMED_POSIX_SEMAPHORES" = x"1" ; then
+    AC_DEFINE(USE_UNNAMED_POSIX_SEMAPHORES, 1, [Define to select unnamed POSIX semaphores])
+    SEMA_IMPLEMENTATION="src/backend/port/posix_sema.c"
+  else
+    AC_DEFINE(USE_SYSV_SEMAPHORES, 1, [Define to select SysV-style semaphores])
+    SEMA_IMPLEMENTATION="src/backend/port/sysv_sema.c"
+  fi
+fi
+
+
+# Select shared-memory implementation type.
+AC_DEFINE(USE_SYSV_SHARED_MEMORY, 1, [Define to select SysV-style shared memory])
+SHMEM_IMPLEMENTATION="src/backend/port/sysv_shmem.c"
+
+
 if test "$enable_nls" = yes ; then
   PGAC_CHECK_GETTEXT
 fi
@@ -1222,6 +1242,8 @@ AC_CONFIG_FILES([GNUmakefile src/Makefile.global])
 
 AC_CONFIG_LINKS([
   src/backend/port/dynloader.c:src/backend/port/dynloader/${template}.c
+  src/backend/port/pg_sema.c:${SEMA_IMPLEMENTATION}
+  src/backend/port/pg_shmem.c:${SHMEM_IMPLEMENTATION}
   src/include/dynloader.h:src/backend/port/dynloader/${template}.h
   src/include/pg_config_os.h:src/include/port/${template}.h
   src/Makefile.port:src/makefiles/Makefile.${template}

src/backend/Makefile

@@ -4,7 +4,7 @@
 #
 # Copyright (c) 1994, Regents of the University of California
 #
-# $Header: /cvsroot/pgsql/src/backend/Makefile,v 1.77 2002/03/13 00:05:05 petere Exp $
+# $Header: /cvsroot/pgsql/src/backend/Makefile,v 1.78 2002/05/05 00:03:28 tgl Exp $
 #
 #-------------------------------------------------------------------------
 
@@ -194,7 +194,7 @@ ifeq ($(enable_nls), yes)
 endif
 
 distclean: clean
-	rm -f port/tas.s port/dynloader.c
+	rm -f port/tas.s port/dynloader.c port/pg_sema.c port/pg_shmem.c
 
 maintainer-clean: distclean
 	rm -f $(srcdir)/bootstrap/bootparse.c \

src/backend/bootstrap/bootstrap.c

@@ -8,7 +8,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/bootstrap/bootstrap.c,v 1.127 2002/04/27 21:24:33 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/bootstrap/bootstrap.c,v 1.128 2002/05/05 00:03:28 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -33,6 +33,7 @@
 #include "catalog/pg_type.h"
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
+#include "storage/ipc.h"
 #include "storage/proc.h"
 #include "tcop/tcopprot.h"
 #include "utils/builtins.h"

src/backend/catalog/namespace.c

@@ -13,7 +13,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/catalog/namespace.c,v 1.17 2002/05/01 23:06:41 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/catalog/namespace.c,v 1.18 2002/05/05 00:03:28 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -36,6 +36,7 @@
 #include "miscadmin.h"
 #include "nodes/makefuncs.h"
 #include "storage/backendid.h"
+#include "storage/ipc.h"
 #include "utils/acl.h"
 #include "utils/builtins.h"
 #include "utils/catcache.h"

src/backend/commands/async.c

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/commands/async.c,v 1.83 2002/03/06 06:09:29 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/commands/async.c,v 1.84 2002/05/05 00:03:28 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -85,6 +85,7 @@
 #include "libpq/libpq.h"
 #include "libpq/pqformat.h"
 #include "miscadmin.h"
+#include "storage/ipc.h"
 #include "tcop/tcopprot.h"
 #include "utils/fmgroids.h"
 #include "utils/ps_status.h"

src/backend/libpq/auth.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/libpq/auth.c,v 1.80 2002/04/04 04:25:47 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/libpq/auth.c,v 1.81 2002/05/05 00:03:28 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -25,6 +25,7 @@
 #endif
 #include <netinet/in.h>
 #include <arpa/inet.h>
+
 #include "libpq/auth.h"
 #include "libpq/crypt.h"
 #include "libpq/hba.h"
@@ -32,6 +33,8 @@
 #include "libpq/password.h"
 #include "libpq/pqformat.h"
 #include "miscadmin.h"
+#include "storage/ipc.h"
+
 
 static void sendAuthRequest(Port *port, AuthRequest areq);
 static int	old_be_recvauth(Port *port);

src/backend/libpq/pqcomm.c

@@ -29,7 +29,7 @@
  * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- *	$Id: pqcomm.c,v 1.132 2002/04/21 01:03:33 tgl Exp $
+ *	$Id: pqcomm.c,v 1.133 2002/05/05 00:03:28 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -79,6 +79,7 @@
 
 #include "libpq/libpq.h"
 #include "miscadmin.h"
+#include "storage/ipc.h"
 
 
 static void pq_close(void);

src/backend/port/Makefile

@@ -13,7 +13,7 @@
 # be converted to Method 2.  
 #
 # IDENTIFICATION
-#    $Header: /cvsroot/pgsql/src/backend/port/Makefile,v 1.11 2002/03/13 00:05:06 petere Exp $
+#    $Header: /cvsroot/pgsql/src/backend/port/Makefile,v 1.12 2002/05/05 00:03:28 tgl Exp $
 #
 #-------------------------------------------------------------------------
 
@@ -21,7 +21,7 @@ subdir = src/backend/port
 top_builddir = ../../..
 include $(top_builddir)/src/Makefile.global
 
-OBJS = dynloader.o
+OBJS = dynloader.o pg_sema.o pg_shmem.o
 
 OBJS += $(GETHOSTNAME) $(GETRUSAGE) $(INET_ATON) $(ISINF) $(MEMCMP) \
         $(MISSING_RANDOM) $(SNPRINTF) $(SRANDOM) $(STRCASECMP) $(STRERROR) \

src/backend/port/posix_sema.c

+/*-------------------------------------------------------------------------
+ *
+ * posix_sema.c
+ *	  Implement PGSemaphores using POSIX semaphore facilities
+ *
+ * We prefer the unnamed style of POSIX semaphore (the kind made with
+ * sem_init).  We can cope with the kind made with sem_open, however.
+ *
+ *
+ * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * IDENTIFICATION
+ *	  $Header: /cvsroot/pgsql/src/backend/port/posix_sema.c,v 1.1 2002/05/05 00:03:28 tgl Exp $
+ *
+ *-------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include <errno.h>
+#include <signal.h>
+#include <unistd.h>
+
+#include "storage/pg_sema.h"
+
+
+#ifdef USE_NAMED_POSIX_SEMAPHORES
+/* PGSemaphore is pointer to pointer to sem_t */
+#define PG_SEM_REF(x)	(*(x))
+#else
+/* PGSemaphore is pointer to sem_t */
+#define PG_SEM_REF(x)	(x)
+#endif
+
+
+#define IPCProtection	(0600)	/* access/modify by user only */
+
+static sem_t **mySemPointers;	/* keep track of created semaphores */
+static int	numSems;			/* number of semas acquired so far */
+static int	maxSems;			/* allocated size of mySemaPointers array */
+static int	nextSemKey;			/* next name to try */
+
+
+static void ReleaseSemaphores(int status, Datum arg);
+
+
+#ifdef USE_NAMED_POSIX_SEMAPHORES
+
+/*
+ * PosixSemaphoreCreate
+ *
+ * Attempt to create a new named semaphore.
+ *
+ * If we fail with a failure code other than collision-with-existing-sema,
+ * print out an error and abort.  Other types of errors suggest nonrecoverable
+ * problems.
+ */
+static sem_t *
+PosixSemaphoreCreate(void)
+{
+	int			semKey;
+	char		semname[64];
+	sem_t	   *mySem;
+
+	for (;;)
+	{
+		semKey = nextSemKey++;
+
+		snprintf(semname, sizeof(semname), "/pgsql-%d", semKey);
+
+		mySem = sem_open(semname, O_CREAT | O_EXCL,
+						 (mode_t) IPCProtection, (unsigned) 1);
+		if (mySem != SEM_FAILED)
+			break;
+
+		/* Loop if error indicates a collision */
+		if (errno == EEXIST || errno == EACCES || errno == EINTR)
+			continue;
+
+		/*
+		 * Else complain and abort
+		 */
+		fprintf(stderr, "PosixSemaphoreCreate: sem_open(%s) failed: %s\n",
+				semname, strerror(errno));
+		proc_exit(1);
+	}
+
+	/*
+	 * Unlink the semaphore immediately, so it can't be accessed externally.
+	 * This also ensures that it will go away if we crash.
+	 */
+	sem_unlink(semname);
+
+	return mySem;
+}
+
+#else /* !USE_NAMED_POSIX_SEMAPHORES */
+
+/*
+ * PosixSemaphoreCreate
+ *
+ * Attempt to create a new unnamed semaphore.
+ */
+static void
+PosixSemaphoreCreate(sem_t *sem)
+{
+	if (sem_init(sem, 1, 1) < 0)
+	{
+		fprintf(stderr, "PosixSemaphoreCreate: sem_init failed: %s\n",
+				strerror(errno));
+		proc_exit(1);
+	}
+}
+
+#endif /* USE_NAMED_POSIX_SEMAPHORES */
+
+
+/*
+ * PosixSemaphoreKill	- removes a semaphore
+ */
+static void
+PosixSemaphoreKill(sem_t *sem)
+{
+#ifdef USE_NAMED_POSIX_SEMAPHORES
+	/* Got to use sem_close for named semaphores */
+	if (sem_close(sem) < 0)
+		fprintf(stderr, "PosixSemaphoreKill: sem_close failed: %s\n",
+				strerror(errno));
+#else
+	/* Got to use sem_destroy for unnamed semaphores */
+	if (sem_destroy(sem) < 0)
+		fprintf(stderr, "PosixSemaphoreKill: sem_destroy failed: %s\n",
+				strerror(errno));
+#endif
+}
+
+
+/*
+ * PGReserveSemaphores --- initialize semaphore support
+ *
+ * This is called during postmaster start or shared memory reinitialization.
+ * It should do whatever is needed to be able to support up to maxSemas
+ * subsequent PGSemaphoreCreate calls.  Also, if any system resources
+ * are acquired here or in PGSemaphoreCreate, register an on_shmem_exit
+ * callback to release them.
+ *
+ * The port number is passed for possible use as a key (for Posix, we use
+ * it to generate the starting semaphore name).  In a standalone backend,
+ * zero will be passed.
+ *
+ * In the Posix implementation, we acquire semaphores on-demand; the
+ * maxSemas parameter is just used to size the array that keeps track of
+ * acquired semas for subsequent releasing.
+ */
+void
+PGReserveSemaphores(int maxSemas, int port)
+{
+	mySemPointers = (sem_t **) malloc(maxSemas * sizeof(sem_t *));
+	if (mySemPointers == NULL)
+		elog(PANIC, "Out of memory in PGReserveSemaphores");
+	numSems = 0;
+	maxSems = maxSemas;
+	nextSemKey = port * 1000;
+
+	on_shmem_exit(ReleaseSemaphores, 0);
+}
+
+/*
+ * Release semaphores at shutdown or shmem reinitialization
+ *
+ * (called as an on_shmem_exit callback, hence funny argument list)
+ */
+static void
+ReleaseSemaphores(int status, Datum arg)
+{
+	int			i;
+
+	for (i = 0; i < numSems; i++)
+		PosixSemaphoreKill(mySemPointers[i]);
+	free(mySemPointers);
+}
+
+/*
+ * PGSemaphoreCreate
+ *
+ * Initialize a PGSemaphore structure to represent a sema with count 1
+ */
+void
+PGSemaphoreCreate(PGSemaphore sema)
+{
+	sem_t  *newsem;
+
+	/* Can't do this in a backend, because static state is postmaster's */
+	Assert(!IsUnderPostmaster);
+
+	if (numSems >= maxSems)
+		elog(PANIC, "PGSemaphoreCreate: too many semaphores created");
+
+#ifdef USE_NAMED_POSIX_SEMAPHORES
+	*sema = newsem = PosixSemaphoreCreate();
+#else
+	PosixSemaphoreCreate(sema);
+	newsem = sema;
+#endif
+
+	/* Remember new sema for ReleaseSemaphores */
+	mySemPointers[numSems++] = newsem;
+}
+
+/*
+ * PGSemaphoreReset
+ *
+ * Reset a previously-initialized PGSemaphore to have count 0
+ */
+void
+PGSemaphoreReset(PGSemaphore sema)
+{
+	/*
+	 * There's no direct API for this in POSIX, so we have to ratchet the
+	 * semaphore down to 0 with repeated trywait's.
+	 */
+	for (;;)
+	{
+		if (sem_trywait(PG_SEM_REF(sema)) < 0)
+		{
+			if (errno == EAGAIN || errno == EDEADLK)
+				break;			/* got it down to 0 */
+			if (errno == EINTR)
+				continue;		/* can this happen? */
+			fprintf(stderr, "PGSemaphoreReset: sem_trywait failed: %s\n",
+					strerror(errno));
+			proc_exit(1);
+		}
+	}
+}
+
+/*
+ * PGSemaphoreLock
+ *
+ * Lock a semaphore (decrement count), blocking if count would be < 0
+ */
+void
+PGSemaphoreLock(PGSemaphore sema, bool interruptOK)
+{
+	int			errStatus;
+
+	/*
+	 * Note: if errStatus is -1 and errno == EINTR then it means we
+	 * returned from the operation prematurely because we were sent a
+	 * signal.	So we try and lock the semaphore again.
+	 *
+	 * Each time around the loop, we check for a cancel/die interrupt. We
+	 * assume that if such an interrupt comes in while we are waiting, it
+	 * will cause the sem_wait() call to exit with errno == EINTR, so that we
+	 * will be able to service the interrupt (if not in a critical 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 the
+	 * lock before any interrupt can be accepted.
+	 *
+	 * There is a window of a few instructions between CHECK_FOR_INTERRUPTS
+	 * and entering the sem_wait() 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 sem_wait()).  We can
+	 * avoid this problem by temporarily setting ImmediateInterruptOK to
+	 * true before we do CHECK_FOR_INTERRUPTS; then, a die() interrupt in
+	 * this interval will execute directly.  However, there is a huge
+	 * pitfall: there is another window of a few instructions after the
+	 * sem_wait() before we are able to reset ImmediateInterruptOK.  If an
+	 * interrupt occurs then, we'll lose control, which means that the
+	 * lock has been acquired but our caller did not get a chance to
+	 * record the fact. Therefore, we only set ImmediateInterruptOK if the
+	 * caller tells us it's OK to do so, ie, the caller does not need to
+	 * record acquiring the lock.  (This is currently true for lockmanager
+	 * locks, since the process that granted us the lock did all the
+	 * necessary state updates. It's not true for Posix semaphores used to
+	 * implement LW locks or emulate spinlocks --- but the wait time for
+	 * such locks should not be very long, anyway.)
+	 */
+	do
+	{
+		ImmediateInterruptOK = interruptOK;
+		CHECK_FOR_INTERRUPTS();
+		errStatus = sem_wait(PG_SEM_REF(sema));
+		ImmediateInterruptOK = false;
+	} while (errStatus < 0 && errno == EINTR);
+
+	if (errStatus < 0)
+	{
+		fprintf(stderr, "PGSemaphoreLock: sem_wait failed: %s\n",
+				strerror(errno));
+		proc_exit(255);
+	}
+}
+
+/*
+ * PGSemaphoreUnlock
+ *
+ * Unlock a semaphore (increment count)
+ */
+void
+PGSemaphoreUnlock(PGSemaphore sema)
+{
+	int			errStatus;
+
+	/*
+	 * Note: if errStatus is -1 and errno == EINTR then it means we
+	 * returned from the operation prematurely because we were sent a
+	 * signal.	So we try and unlock the semaphore again. Not clear this
+	 * can really happen, but might as well cope.
+	 */
+	do
+	{
+		errStatus = sem_post(PG_SEM_REF(sema));
+	} while (errStatus < 0 && errno == EINTR);
+
+	if (errStatus < 0)
+	{
+		fprintf(stderr, "PGSemaphoreUnlock: sem_post failed: %s\n",
+				strerror(errno));
+		proc_exit(255);
+	}
+}
+
+/*
+ * PGSemaphoreTryLock
+ *
+ * Lock a semaphore only if able to do so without blocking
+ */
+bool
+PGSemaphoreTryLock(PGSemaphore sema)
+{
+	int			errStatus;
+
+	/*
+	 * Note: if errStatus is -1 and errno == EINTR then it means we
+	 * returned from the operation prematurely because we were sent a
+	 * signal.	So we try and lock the semaphore again.
+	 */
+	do
+	{
+		errStatus = sem_trywait(PG_SEM_REF(sema));
+	} while (errStatus < 0 && errno == EINTR);
+
+	if (errStatus < 0)
+	{
+		if (errno == EAGAIN || errno == EDEADLK)
+			return false;		/* failed to lock it */
+		/* Otherwise we got trouble */
+		fprintf(stderr, "PGSemaphoreTryLock: sem_trywait failed: %s\n",
+				strerror(errno));
+		proc_exit(255);
+	}
+
+	return true;
+}

src/backend/postmaster/pgstat.c

@@ -16,7 +16,7 @@
  *
  *	Copyright (c) 2001, PostgreSQL Global Development Group
  *
- *	$Header: /cvsroot/pgsql/src/backend/postmaster/pgstat.c,v 1.19 2002/04/03 00:27:25 tgl Exp $
+ *	$Header: /cvsroot/pgsql/src/backend/postmaster/pgstat.c,v 1.20 2002/05/05 00:03:28 tgl Exp $
  * ----------
  */
 #include "postgres.h"
@@ -44,6 +44,7 @@
 #include "miscadmin.h"
 #include "utils/memutils.h"
 #include "storage/backendid.h"
+#include "storage/ipc.h"
 #include "utils/rel.h"
 #include "utils/hsearch.h"
 #include "utils/ps_status.h"

src/backend/postmaster/postmaster.c

@@ -37,7 +37,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/postmaster/postmaster.c,v 1.272 2002/04/04 04:25:48 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/postmaster/postmaster.c,v 1.273 2002/05/05 00:03:28 tgl Exp $
  *
  * NOTES
  *
@@ -1361,18 +1361,15 @@ ClosePostmasterPorts(bool pgstat_too)
 static void
 reset_shared(unsigned short port)
 {
-	/*
-	 * Reset assignment of shared mem and semaphore IPC keys. Doing this
-	 * means that in normal cases we'll assign the same keys on each
-	 * "cycle of life", and thereby avoid leaving dead IPC objects
-	 * floating around if the postmaster crashes and is restarted.
-	 */
-	IpcInitKeyAssignment(port);
-
 	/*
 	 * Create or re-create shared memory and semaphores.
+	 *
+	 * Note: in each "cycle of life" we will normally assign the same IPC
+	 * keys (if using SysV shmem and/or semas), since the port number is
+	 * used to determine IPC keys.  This helps ensure that we will clean up
+	 * dead IPC objects if the postmaster crashes and is restarted.
 	 */
-	CreateSharedMemoryAndSemaphores(false, MaxBackends);
+	CreateSharedMemoryAndSemaphores(false, MaxBackends, port);
 }
 
 

src/backend/storage/file/fd.c

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/storage/file/fd.c,v 1.90 2002/03/06 06:10:03 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/storage/file/fd.c,v 1.91 2002/05/05 00:03:28 tgl Exp $
  *
  * NOTES:
  *
@@ -51,6 +51,7 @@
 
 #include "miscadmin.h"
 #include "storage/fd.h"
+#include "storage/ipc.h"
 
 
 /* Filename components for OpenTemporaryFile */

src/backend/storage/ipc/ipci.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/storage/ipc/ipci.c,v 1.46 2002/03/02 21:39:29 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/storage/ipc/ipci.c,v 1.47 2002/05/05 00:03:28 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -21,8 +21,11 @@
 #include "access/xlog.h"
 #include "storage/bufmgr.h"
 #include "storage/freespace.h"
+#include "storage/ipc.h"
 #include "storage/lmgr.h"
 #include "storage/lwlock.h"
+#include "storage/pg_sema.h"
+#include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
 #include "storage/proc.h"
 #include "storage/sinval.h"
@@ -41,9 +44,12 @@
  * memory.	This is true for a standalone backend, false for a postmaster.
  */
 void
-CreateSharedMemoryAndSemaphores(bool makePrivate, int maxBackends)
+CreateSharedMemoryAndSemaphores(bool makePrivate,
+								int maxBackends,
+								int port)
 {
 	int			size;
+	int			numSemas;
 	PGShmemHeader *seghdr;
 
 	/*
@@ -70,12 +76,14 @@ CreateSharedMemoryAndSemaphores(bool makePrivate, int maxBackends)
 	/*
 	 * Create the shmem segment
 	 */
-	seghdr = IpcMemoryCreate(size, makePrivate, IPCProtection);
+	seghdr = PGSharedMemoryCreate(size, makePrivate, port);
 
 	/*
-	 * First initialize spinlocks --- needed by InitShmemAllocation()
+	 * Create semaphores
 	 */
-	CreateSpinlocks();
+	numSemas = ProcGlobalSemas(maxBackends);
+	numSemas += SpinlockSemas();
+	PGReserveSemaphores(numSemas, port);
 
 	/*
 	 * Set up shared memory allocation mechanism

src/backend/storage/ipc/shmem.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/storage/ipc/shmem.c,v 1.64 2002/03/06 06:10:05 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/storage/ipc/shmem.c,v 1.65 2002/05/05 00:03:28 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -61,6 +61,7 @@
 #include "postgres.h"
 
 #include "access/transam.h"
+#include "storage/pg_shmem.h"
 #include "storage/spin.h"
 #include "utils/tqual.h"
 

src/backend/storage/ipc/sinvaladt.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/storage/ipc/sinvaladt.c,v 1.45 2002/03/02 23:35:57 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/storage/ipc/sinvaladt.c,v 1.46 2002/05/05 00:03:28 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -16,6 +16,7 @@
 
 #include "miscadmin.h"
 #include "storage/backendid.h"
+#include "storage/ipc.h"
 #include "storage/pmsignal.h"
 #include "storage/proc.h"
 #include "storage/sinvaladt.h"

src/backend/storage/lmgr/lwlock.c

@@ -15,7 +15,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/storage/lmgr/lwlock.c,v 1.9 2002/03/02 21:39:29 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/storage/lmgr/lwlock.c,v 1.10 2002/05/05 00:03:28 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -302,7 +302,7 @@ LWLockAcquire(LWLockId lockid, LWLockMode mode)
 		for (;;)
 		{
 			/* "false" means cannot accept cancel/die interrupt here. */
-			IpcSemaphoreLock(proc->sem.semId, proc->sem.semNum, false);
+			PGSemaphoreLock(&proc->sem, false);
 			if (!proc->lwWaiting)
 				break;
 			extraWaits++;
@@ -325,7 +325,7 @@ LWLockAcquire(LWLockId lockid, LWLockMode mode)
 	 * Fix the process wait semaphore's count for any absorbed wakeups.
 	 */
 	while (extraWaits-- > 0)
-		IpcSemaphoreUnlock(proc->sem.semId, proc->sem.semNum);
+		PGSemaphoreUnlock(&proc->sem);
 }
 
 /*
@@ -485,7 +485,7 @@ LWLockRelease(LWLockId lockid)
 		head = proc->lwWaitLink;
 		proc->lwWaitLink = NULL;
 		proc->lwWaiting = false;
-		IpcSemaphoreUnlock(proc->sem.semId, proc->sem.semNum);
+		PGSemaphoreUnlock(&proc->sem);
 	}
 
 	/*

src/backend/storage/lmgr/spin.c

@@ -6,7 +6,8 @@
  *
  * For machines that have test-and-set (TAS) instructions, s_lock.h/.c
  * define the spinlock implementation.	This file contains only a stub
- * implementation for spinlocks using SysV semaphores.	The semaphore method
+ * implementation for spinlocks using PGSemaphores.  Unless semaphores
+ * are implemented in a way that doesn't involve a kernel call, this
  * is too slow to be very useful :-(
  *
  *
@@ -15,143 +16,49 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/storage/lmgr/spin.c,v 1.7 2001/11/05 17:46:28 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/storage/lmgr/spin.c,v 1.8 2002/05/05 00:03:28 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
 #include "postgres.h"
 
-#include <errno.h>
-
-#include "storage/ipc.h"
-/* In Ultrix, sem.h and shm.h must be included AFTER ipc.h */
-#ifdef HAVE_SYS_SEM_H
-#include <sys/sem.h>
-#endif
-
-#if defined(__darwin__)
-#include "port/darwin/sem.h"
-#endif
-
 #include "storage/lwlock.h"
-#include "storage/proc.h"
+#include "storage/pg_sema.h"
 #include "storage/spin.h"
 
 
 #ifdef HAS_TEST_AND_SET
 
 /*
- * CreateSpinlocks --- create and initialize spinlocks during startup
+ * Report number of semaphores needed to support spinlocks.
  */
-void
-CreateSpinlocks(void)
+int
+SpinlockSemas(void)
 {
-	/* no-op when we have TAS spinlocks */
+	return 0;
 }
 
 #else							/* !HAS_TEST_AND_SET */
 
 /*
- * No TAS, so spinlocks are implemented using SysV semaphores.
- *
- * Typedef slock_t stores the semId and sem number of the sema to use.
- * The semas needed are created by CreateSpinlocks and doled out by
- * s_init_lock_sema.
- *
- * Since many systems have a rather small SEMMSL limit on semas per set,
- * we allocate the semaphores required in sets of SPINLOCKS_PER_SET semas.
- * This value is deliberately made equal to PROC_NSEMS_PER_SET so that all
- * sema sets allocated by Postgres will be the same size; that eases the
- * semaphore-recycling logic in IpcSemaphoreCreate().
- *
- * Note that the SpinLockIds array is not in shared memory; it is filled
- * by the postmaster and then inherited through fork() by backends.  This
- * is OK because its contents do not change after shmem initialization.
+ * No TAS, so spinlocks are implemented as PGSemaphores.
  */
 
-#define SPINLOCKS_PER_SET  PROC_NSEMS_PER_SET
-
-static IpcSemaphoreId *SpinLockIds = NULL;
-
-static int	numSpinSets = 0;	/* number of sema sets used */
-static int	numSpinLocks = 0;	/* total number of semas allocated */
-static int	nextSpinLock = 0;	/* next free spinlock index */
-
-static void SpinFreeAllSemaphores(void);
-
 
 /*
- * CreateSpinlocks --- create and initialize spinlocks during startup
+ * Report number of semaphores needed to support spinlocks.
  */
-void
-CreateSpinlocks(void)
+int
+SpinlockSemas(void)
 {
-	int			i;
-
-	if (SpinLockIds == NULL)
-	{
-		/*
-		 * Compute number of spinlocks needed.	It would be cleaner to
-		 * distribute this logic into the affected modules, similar to the
-		 * way shmem space estimation is handled.
-		 *
-		 * For now, though, we just need a few spinlocks (10 should be
-		 * plenty) plus one for each LWLock.
-		 */
-		numSpinLocks = NumLWLocks() + 10;
-
-		/* might as well round up to a multiple of SPINLOCKS_PER_SET */
-		numSpinSets = (numSpinLocks - 1) / SPINLOCKS_PER_SET + 1;
-		numSpinLocks = numSpinSets * SPINLOCKS_PER_SET;
-
-		SpinLockIds = (IpcSemaphoreId *)
-			malloc(numSpinSets * sizeof(IpcSemaphoreId));
-		Assert(SpinLockIds != NULL);
-	}
-
-	for (i = 0; i < numSpinSets; i++)
-		SpinLockIds[i] = -1;
-
 	/*
-	 * Arrange to delete semas on exit --- set this up now so that we will
-	 * clean up if allocation fails.  We use our own freeproc, rather than
-	 * IpcSemaphoreCreate's removeOnExit option, because we don't want to
-	 * fill up the on_shmem_exit list with a separate entry for each
-	 * semaphore set.
+	 * It would be cleaner to distribute this logic into the affected modules,
+	 * similar to the way shmem space estimation is handled.
+	 *
+	 * For now, though, we just need a few spinlocks (10 should be
+	 * plenty) plus one for each LWLock.
 	 */
-	on_shmem_exit(SpinFreeAllSemaphores, 0);
-
-	/* Create sema sets and set all semas to count 1 */
-	for (i = 0; i < numSpinSets; i++)
-	{
-		SpinLockIds[i] = IpcSemaphoreCreate(SPINLOCKS_PER_SET,
-											IPCProtection,
-											1,
-											false);
-	}
-
-	/* Init counter for allocating dynamic spinlocks */
-	nextSpinLock = 0;
-}
-
-/*
- * SpinFreeAllSemaphores -
- *	  called at shmem_exit time, ie when exiting the postmaster or
- *	  destroying shared state for a failed set of backends.
- *	  Free up all the semaphores allocated for spinlocks.
- */
-static void
-SpinFreeAllSemaphores(void)
-{
-	int			i;
-
-	for (i = 0; i < numSpinSets; i++)
-	{
-		if (SpinLockIds[i] >= 0)
-			IpcSemaphoreKill(SpinLockIds[i]);
-	}
-	free(SpinLockIds);
-	SpinLockIds = NULL;
+	return NumLWLocks() + 10;
 }
 
 /*
@@ -161,30 +68,28 @@ SpinFreeAllSemaphores(void)
 void
 s_init_lock_sema(volatile slock_t *lock)
 {
-	if (nextSpinLock >= numSpinLocks)
-		elog(FATAL, "s_init_lock_sema: not enough semaphores");
-	lock->semId = SpinLockIds[nextSpinLock / SPINLOCKS_PER_SET];
-	lock->sem = nextSpinLock % SPINLOCKS_PER_SET;
-	nextSpinLock++;
+	PGSemaphoreCreate((PGSemaphore) lock);
 }
 
 void
 s_unlock_sema(volatile slock_t *lock)
 {
-	IpcSemaphoreUnlock(lock->semId, lock->sem);
+	PGSemaphoreUnlock((PGSemaphore) lock);
 }
 
 bool
 s_lock_free_sema(volatile slock_t *lock)
 {
-	return IpcSemaphoreGetValue(lock->semId, lock->sem) > 0;
+	/* We don't currently use S_LOCK_FREE anyway */
+	elog(ERROR, "spin.c does not support S_LOCK_FREE()");
+	return false;
 }
 
 int
 tas_sema(volatile slock_t *lock)
 {
 	/* Note that TAS macros return 0 if *success* */
-	return !IpcSemaphoreTryLock(lock->semId, lock->sem);
+	return !PGSemaphoreTryLock((PGSemaphore) lock);
 }
 
 #endif   /* !HAS_TEST_AND_SET */

src/backend/tcop/postgres.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/tcop/postgres.c,v 1.262 2002/04/20 21:56:15 petere Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/tcop/postgres.c,v 1.263 2002/05/05 00:03:28 tgl Exp $
  *
  * NOTES
  *	  this is the "main" module of the postgres backend and
@@ -49,11 +49,12 @@
 #include "parser/parse.h"
 #include "parser/parser.h"
 #include "rewrite/rewriteHandler.h"
+#include "storage/ipc.h"
+#include "storage/proc.h"
 #include "tcop/fastpath.h"
 #include "tcop/pquery.h"
 #include "tcop/tcopprot.h"
 #include "tcop/utility.h"
-#include "storage/proc.h"
 #include "utils/exc.h"
 #include "utils/guc.h"
 #include "utils/memutils.h"
@@ -1692,7 +1693,7 @@ PostgresMain(int argc, char *argv[], const char *username)
 	if (!IsUnderPostmaster)
 	{
 		puts("\nPOSTGRES backend interactive interface ");
-		puts("$Revision: 1.262 $ $Date: 2002/04/20 21:56:15 $\n");
+		puts("$Revision: 1.263 $ $Date: 2002/05/05 00:03:28 $\n");
 	}
 
 	/*

src/backend/utils/error/elog.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/utils/error/elog.c,v 1.96 2002/04/21 00:22:52 ishii Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/utils/error/elog.c,v 1.97 2002/05/05 00:03:29 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -30,6 +30,7 @@
 #include "libpq/libpq.h"
 #include "libpq/pqformat.h"
 #include "miscadmin.h"
+#include "storage/ipc.h"
 #include "storage/proc.h"
 #include "tcop/tcopprot.h"
 #include "utils/memutils.h"

src/backend/utils/init/miscinit.c

@@ -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

src/backend/utils/init/postinit.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/utils/init/postinit.c,v 1.103 2002/04/27 21:24:34 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/utils/init/postinit.c,v 1.104 2002/05/05 00:03:29 tgl Exp $
  *
  *
  *-------------------------------------------------------------------------
@@ -32,6 +32,7 @@
 #include "mb/pg_wchar.h"
 #include "miscadmin.h"
 #include "storage/backendid.h"
+#include "storage/ipc.h"
 #include "storage/proc.h"
 #include "storage/sinval.h"
 #include "storage/smgr.h"
@@ -181,7 +182,7 @@ InitCommunication(void)
 		 * postmaster.	Create private "shmem" and semaphores.	Setting
 		 * MaxBackends = 16 is arbitrary.
 		 */
-		CreateSharedMemoryAndSemaphores(true, 16);
+		CreateSharedMemoryAndSemaphores(true, 16, 0);
 	}
 }
 

src/include/miscadmin.h

@@ -12,7 +12,7 @@
  * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Id: miscadmin.h,v 1.102 2002/04/04 04:25:51 momjian Exp $
+ * $Id: miscadmin.h,v 1.103 2002/05/05 00:03:29 tgl Exp $
  *
  * NOTES
  *	  some of the information in this file should be moved to
@@ -23,7 +23,8 @@
 #ifndef MISCADMIN_H
 #define MISCADMIN_H
 
-#include "storage/ipc.h"
+#include <sys/types.h>
+
 
 /*****************************************************************************
  *	  System interrupt and critical section handling
@@ -291,8 +292,8 @@ extern void BaseInit(void);
 extern bool CreateDataDirLockFile(const char *datadir, bool amPostmaster);
 extern bool CreateSocketLockFile(const char *socketfile, bool amPostmaster);
 extern void TouchSocketLockFile(void);
-extern void RecordSharedMemoryInLockFile(IpcMemoryKey shmKey,
-							 IpcMemoryId shmId);
+extern void RecordSharedMemoryInLockFile(unsigned long id1,
+										 unsigned long id2);
 
 extern void ValidatePgVersion(const char *path);
 

src/include/pg_config.h.in

@@ -8,7 +8,7 @@
  * or in pg_config.h afterwards.  Of course, if you edit pg_config.h, then your
  * changes will be overwritten the next time you run configure.
  *
- * $Id: pg_config.h.in,v 1.23 2002/04/21 19:48:19 thomas Exp $
+ * $Id: pg_config.h.in,v 1.24 2002/05/05 00:03:29 tgl Exp $
  */
 
 #ifndef PG_CONFIG_H
@@ -711,6 +711,15 @@ extern int fdatasync(int fildes);
 /* Define if you have syslog() */
 #undef HAVE_SYSLOG
 
+/* Define exactly one of these symbols to select semaphore implementation */
+#undef USE_NAMED_POSIX_SEMAPHORES
+#undef USE_UNNAMED_POSIX_SEMAPHORES
+#undef USE_SYSV_SEMAPHORES
+
+/* Define exactly one of these symbols to select shared-mem implementation */
+#undef USE_SYSV_SHARED_MEMORY
+
+
 /*
  *------------------------------------------------------------------------
  * Part 4: pull in system-specific declarations.

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 */

src/include/storage/pg_sema.h

+/*-------------------------------------------------------------------------
+ *
+ * pg_sema.h
+ *	  Platform-independent API for semaphores.
+ *
+ * PostgreSQL requires counting semaphores (the kind that keep track of
+ * multiple unlock operations, and will allow an equal number of subsequent
+ * lock operations before blocking).  The underlying implementation is
+ * not the same on every platform.  This file defines the API that must
+ * be provided by each port.
+ *
+ *
+ * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * $Id: pg_sema.h,v 1.1 2002/05/05 00:03:29 tgl Exp $
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef PG_SEMA_H
+#define PG_SEMA_H
+
+/*
+ * PGSemaphoreData and pointer type PGSemaphore are the data structure
+ * representing an individual semaphore.  The contents of PGSemaphoreData
+ * vary across implementations and must never be touched by platform-
+ * independent code.  PGSemaphoreData structures are always allocated
+ * in shared memory (to support implementations where the data changes during
+ * lock/unlock).
+ *
+ * pg_config.h must define exactly one of the USE_xxx_SEMAPHORES symbols.
+ */
+
+#ifdef USE_NAMED_POSIX_SEMAPHORES
+
+#include <semaphore.h>
+
+typedef sem_t *PGSemaphoreData;
+
+#endif
+
+#ifdef USE_UNNAMED_POSIX_SEMAPHORES
+
+#include <semaphore.h>
+
+typedef sem_t PGSemaphoreData;
+
+#endif
+
+#ifdef USE_SYSV_SEMAPHORES
+
+typedef struct PGSemaphoreData
+{
+	int			semId;			/* semaphore set identifier */
+	int			semNum;			/* semaphore number within set */
+} PGSemaphoreData;
+
+#endif
+
+typedef PGSemaphoreData *PGSemaphore;
+
+
+/* Module initialization (called during postmaster start or shmem reinit) */
+extern void PGReserveSemaphores(int maxSemas, int port);
+/* Initialize a PGSemaphore structure to represent a sema with count 1 */
+extern void PGSemaphoreCreate(PGSemaphore sema);
+/* Reset a previously-initialized PGSemaphore to have count 0 */
+extern void PGSemaphoreReset(PGSemaphore sema);
+/* Lock a semaphore (decrement count), blocking if count would be < 0 */
+extern void PGSemaphoreLock(PGSemaphore sema, bool interruptOK);
+/* Unlock a semaphore (increment count) */
+extern void PGSemaphoreUnlock(PGSemaphore sema);
+/* Lock a semaphore only if able to do so without blocking */
+extern bool PGSemaphoreTryLock(PGSemaphore sema);
+
+#endif   /* PG_SEMA_H */

src/include/storage/pg_shmem.h

+/*-------------------------------------------------------------------------
+ *
+ * pg_shmem.h
+ *	  Platform-independent API for shared memory support.
+ *
+ * Every port is expected to support shared memory with approximately
+ * SysV-ish semantics; in particular, a memory block is not anonymous
+ * but has an ID, and we must be able to tell whether there are any
+ * remaining processes attached to a block of a specified ID.
+ *
+ * To simplify life for the SysV implementation, the ID is assumed to
+ * consist of two unsigned long values (these are key and ID in SysV
+ * terms).  Other platforms may ignore the second value if they need
+ * only one ID number.
+ *
+ *
+ * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * $Id: pg_shmem.h,v 1.1 2002/05/05 00:03:29 tgl Exp $
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef PG_SHMEM_H
+#define PG_SHMEM_H
+
+#include <sys/types.h>
+
+
+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;
+
+
+extern PGShmemHeader *PGSharedMemoryCreate(uint32 size, bool makePrivate,
+										   int port);
+extern bool PGSharedMemoryIsInUse(unsigned long id1, unsigned long id2);
+
+#endif   /* PG_SHMEM_H */

src/include/storage/proc.h

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Id: proc.h,v 1.54 2001/11/06 00:38:26 tgl Exp $
+ * $Id: proc.h,v 1.55 2002/05/05 00:03:29 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -16,16 +16,10 @@
 
 #include "access/xlog.h"
 #include "storage/backendid.h"
-#include "storage/ipc.h"
 #include "storage/lock.h"
+#include "storage/pg_sema.h"
 
 
-typedef struct
-{
-	IpcSemaphoreId semId;		/* SysV semaphore set ID */
-	int			semNum;			/* semaphore number within set */
-} SEMA;
-
 /*
  * Each backend has a PROC struct in shared memory.  There is also a list of
  * currently-unused PROC structs that will be reallocated to new backends.
@@ -39,7 +33,7 @@ struct PROC
 	/* proc->links MUST BE FIRST IN STRUCT (see ProcSleep,ProcWakeup,etc) */
 	SHM_QUEUE	links;			/* list link if process is in a list */
 
-	SEMA		sem;			/* ONE semaphore to sleep on */
+	PGSemaphoreData sem;		/* ONE semaphore to sleep on */
 	int			errType;		/* STATUS_OK or STATUS_ERROR after wakeup */
 
 	TransactionId xid;			/* transaction currently being executed by
@@ -84,47 +78,11 @@ extern PROC *MyProc;
 
 /*
  * There is one ProcGlobal struct for the whole installation.
- *
- * PROC_NSEMS_PER_SET is the number of semaphores in each sys-V semaphore set
- * we allocate.  It must be no more than 32 (or however many bits in an int
- * on your machine), or our free-semaphores bitmap won't work.  It also must
- * be *less than* your kernel's SEMMSL (max semaphores per set) parameter,
- * which is often around 25.  (Less than, because we allocate one extra sema
- * in each set for identification purposes.)
- *
- * PROC_SEM_MAP_ENTRIES is the number of semaphore sets we need to allocate
- * to keep track of up to maxBackends backends.  Note that we need one extra
- * semaphore (see storage/lmgr/proc.c), so the computation may look wrong,
- * but it's right.
  */
-#define  PROC_NSEMS_PER_SET		16
-#define  PROC_SEM_MAP_ENTRIES(maxBackends)	((maxBackends)/PROC_NSEMS_PER_SET+1)
-
-typedef struct
-{
-	/* info about a single set of per-process semaphores */
-	IpcSemaphoreId procSemId;
-	int32		freeSemMap;
-
-	/*
-	 * In freeSemMap, bit i is set if the i'th semaphore of this sema set
-	 * is allocated to a process.  (i counts from 0 at the LSB)
-	 */
-} SEM_MAP_ENTRY;
-
 typedef struct PROC_HDR
 {
 	/* Head of list of free PROC structures */
 	SHMEM_OFFSET freeProcs;
-
-	/* Info about semaphore sets used for per-process semaphores */
-	int			semMapEntries;
-
-	/*
-	 * VARIABLE LENGTH ARRAY: actual length is semMapEntries. THIS MUST BE
-	 * LAST IN THE STRUCT DECLARATION.
-	 */
-	SEM_MAP_ENTRY procSemMap[1];
 } PROC_HDR;
 
 
@@ -135,6 +93,7 @@ extern int	DeadlockTimeout;
 /*
  * Function Prototypes
  */
+extern int	ProcGlobalSemas(int maxBackends);
 extern void InitProcGlobal(int maxBackends);
 extern void InitProcess(void);
 extern void InitDummyProcess(void);

src/include/storage/s_lock.h

@@ -63,14 +63,14 @@
  * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- *	  $Id: s_lock.h,v 1.97 2002/01/29 15:44:42 tgl Exp $
+ *	  $Id: s_lock.h,v 1.98 2002/05/05 00:03:29 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
 #ifndef S_LOCK_H
 #define S_LOCK_H
 
-#include "storage/ipc.h"
+#include "storage/pg_sema.h"
 
 
 #if defined(HAS_TEST_AND_SET)
@@ -438,7 +438,6 @@ extern slock_t wc_tas(volatile slock_t *lock);
  * AIX (POWER)
  *
  * Note that slock_t on POWER/POWER2/PowerPC is int instead of char
- * (see storage/ipc.h).
  */
 #define TAS(lock)	cs((int *) (lock), 0, 1)
 #endif	 /* _AIX */
@@ -462,17 +461,11 @@ extern slock_t wc_tas(volatile slock_t *lock);
 #else							/* !HAS_TEST_AND_SET */
 
 /*
- * Fake spinlock implementation using SysV semaphores --- slow and prone
+ * Fake spinlock implementation using semaphores --- slow and prone
  * to fall foul of kernel limits on number of semaphores, so don't use this
  * unless you must!  The subroutines appear in spin.c.
  */
-
-typedef struct
-{
-	/* reference to semaphore used to implement this spinlock */
-	IpcSemaphoreId semId;
-	int			sem;
-} slock_t;
+typedef PGSemaphoreData slock_t;
 
 extern bool s_lock_free_sema(volatile slock_t *lock);
 extern void s_unlock_sema(volatile slock_t *lock);

src/include/storage/spin.h

@@ -40,7 +40,7 @@
  * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Id: spin.h,v 1.19 2001/11/05 17:46:35 momjian Exp $
+ * $Id: spin.h,v 1.20 2002/05/05 00:03:29 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -72,6 +72,6 @@
 #define SpinLockFree(lock)	S_LOCK_FREE(lock)
 
 
-extern void CreateSpinlocks(void);
+extern int	SpinlockSemas(void);
 
 #endif   /* SPIN_H */

src/pl/plperl/SPI.xs

@@ -21,22 +21,6 @@
 #include "catalog/pg_type.h"
 
 /* perl stuff */
-/*
- * Evil Code Alert
- *
- * both posgreSQL and perl try to do 'the right thing'
- * and provide union semun if the platform doesn't define
- * it in a system header.
- * psql uses HAVE_UNION_SEMUN
- * perl uses HAS_UNION_SEMUN
- * together, they cause compile errors.
- * If we need it, the psql headers above will provide it.
- * So we tell perl that we have it.
- */
-#ifndef HAS_UNION_SEMUN
-#define HAS_UNION_SEMUN
-#endif
-
 #include "EXTERN.h"
 #include "perl.h"
 #include "XSUB.h"

src/pl/plperl/plperl.c

@@ -33,7 +33,7 @@
  *	  ENHANCEMENTS, OR MODIFICATIONS.
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/pl/plperl/plperl.c,v 1.29 2002/03/06 18:50:26 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/pl/plperl/plperl.c,v 1.30 2002/05/05 00:03:29 tgl Exp $
  *
  **********************************************************************/
 
@@ -62,22 +62,6 @@
 #include "catalog/pg_type.h"
 
 /* perl stuff */
-/*
- * Evil Code Alert
- *
- * both posgreSQL and perl try to do 'the right thing'
- * and provide union semun if the platform doesn't define
- * it in a system header.
- * psql uses HAVE_UNION_SEMUN
- * perl uses HAS_UNION_SEMUN
- * together, they cause compile errors.
- * If we need it, the psql headers above will provide it.
- * So we tell perl that we have it.
- */
-#ifndef HAS_UNION_SEMUN
-#define HAS_UNION_SEMUN
-#endif
-
 #include "EXTERN.h"
 #include "perl.h"
 #include "XSUB.h"

src/template/darwin

 # -traditional-cpp means "don't use apple's cpp-precomp" on darwin
 # this should change to -no-cpp-precomp when that flag is implemented
 CC="$CC -traditional-cpp"
+
+# Select appropriate semaphore support
+USE_NAMED_POSIX_SEMAPHORES=1