Index: configure.in
===================================================================
RCS file: /home/pqcvs/pgsql/configure.in,v
retrieving revision 1.409
diff -u -u -r1.409 configure.in
--- configure.in	5 May 2005 19:15:54 -0000	1.409
+++ configure.in	6 May 2005 12:03:26 -0000
@@ -1240,20 +1240,26 @@
 if test x"$USE_NAMED_POSIX_SEMAPHORES" = x"1" ; then
   AC_DEFINE(USE_NAMED_POSIX_SEMAPHORES, 1, [Define to select named POSIX semaphores.])
   SEMA_IMPLEMENTATION="src/backend/port/posix_sema.c"
+elif test x"$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"
+elif test x"$USE_PIPE_SEMAPHORES" = x"1" ; then
+  AC_DEFINE(USE_PIPE_SEMAPHORES, 1, [Define to select pipe()-based semaphores.])
+  SEMA_IMPLEMENTATION="src/backend/port/pipe_sema.c"
 else
-  if test x"$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
+  AC_DEFINE(USE_SYSV_SEMAPHORES, 1, [Define to select SysV-style semaphores.])
+  SEMA_IMPLEMENTATION="src/backend/port/sysv_sema.c"
 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 x"$USE_MMAP_SHARED_MEMORY" = x"1" ; then
+  AC_DEFINE(USE_MMAP_SHARED_MEMORY, 1, [Define to select mmap()-based shared memory.])
+  SHMEM_IMPLEMENTATION="src/backend/port/mmap_shmem.c"
+else
+  AC_DEFINE(USE_SYSV_SHARED_MEMORY, 1, [Define to select SysV-style shared memory.])
+  SHMEM_IMPLEMENTATION="src/backend/port/sysv_shmem.c"
+fi
 
 
 if test "$enable_nls" = yes ; then
Index: src/backend/port/mmap_shmem.c
===================================================================
RCS file: src/backend/port/mmap_shmem.c
diff -N src/backend/port/mmap_shmem.c
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/backend/port/mmap_shmem.c	6 May 2005 12:09:45 -0000
@@ -0,0 +1,138 @@
+/*-------------------------------------------------------------------------
+ *
+ * mmap_shmem.c
+ *	  Implement shared memory using mmap()
+ *
+ * Portions Copyright (c) 2005 Dag-Erling Coïdan Smørgrav
+ * Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * IDENTIFICATION
+ *	  $PostgreSQL$
+ *
+ *-------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include <sys/mman.h>
+
+#include <errno.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+#include "miscadmin.h"
+#include "storage/ipc.h"
+#include "storage/pg_shmem.h"
+
+#ifdef EXEC_BACKEND
+/* there is no way to reattach to a segment after exec */
+#error mmap()-based shared memory can not be combined with EXEC_BACKEND
+#endif /* EXEC_BACKEND */
+
+#if !defined(MAP_ANON)
+#if defined(MAP_ANONYMOUS)
+#define MAP_ANON MAP_ANONYMOUS
+#else
+static const char  *DevZero = "/dev/zero";
+#endif
+#endif
+
+static int			ShmemFileDescriptor = -1;
+static void		   *ShmemSegmentAddress = NULL;
+static size_t		ShmemSegmentSize = 0;
+
+bool
+PGSharedMemoryIsInUse(unsigned long id1, unsigned long id2)
+{
+    /*
+     * This is never the case when using mmap(), since the segments will
+     * vanish into thin air when postmaster exits or crashes.
+     */
+	return false;
+}
+
+static void
+PGSharedMemoryDestroy(int code, Datum arg)
+{
+	PGSharedMemoryDetach();
+}
+
+PGShmemHeader *
+PGSharedMemoryCreate(uint32 size, bool makePrivate, int port)
+{
+	PGShmemHeader *hdr;
+	void	   *memAddress;
+	int			fd, flags, prot;
+
+	/* Room for a header? */
+	Assert(size > MAXALIGN(sizeof(PGShmemHeader)));
+
+	/* flags: shared, keep out of core dump, don't sync gratuitously */
+	flags = MAP_SHARED;
+#ifdef MAP_NOCORE
+	flags |= MAP_NOCORE;
+#endif
+#ifdef MAP_NOSYNC
+	flags |= MAP_NOSYNC;
+#endif
+
+	/* file descriptor */
+#if defined(MAP_ANON)
+	/* no file needed, just set MAP_ANON */
+	fd = -1;
+	flags |= MAP_ANON;
+#else
+	/* use /dev/zero; need a new file descriptor for every segment */
+	if ((fd = open(DevZero, O_RDWR)) == -1)
+		ereport(FATAL,
+				(errmsg("could not create shared memory segment: %m"),
+		errdetail("Failed system call was open(path='%s', flags=0%o).",
+				  DevZero, O_RDWR)));
+#endif
+
+	/* protection: read-write */
+	prot = PROT_READ | PROT_WRITE;
+
+	/* map it */
+	memAddress = mmap(NULL, (size_t) size, prot, flags, fd, 0);
+	if (memAddress == NULL)
+		ereport(FATAL,
+				(errmsg("could not create shared memory segment: %m"),
+		errdetail("Failed system call was mmap(size=%lu, prot=0%o, flags=0%o, fd=%d).",
+				  (unsigned long) size, prot, flags, fd)));
+
+	/*
+	 * Most header fields are irrelevant since no-one will ever see this
+	 * segment except us and our children.  We only need to fill in those
+	 * required for memory management.
+	 */
+	hdr = (PGShmemHeader *) memAddress;
+	hdr->totalsize = size;
+	hdr->freeoffset = MAXALIGN(sizeof(PGShmemHeader));
+
+	/* save these for detach */
+	ShmemFileDescriptor = fd;
+	ShmemSegmentAddress = memAddress;
+	ShmemSegmentSize = (size_t) size;
+
+	on_shmem_exit(PGSharedMemoryDestroy, 0);
+
+	return hdr;
+}
+
+void
+PGSharedMemoryDetach(void)
+{
+	if (ShmemSegmentAddress != NULL) {
+		if (munmap(ShmemSegmentAddress, ShmemSegmentSize) == -1)
+			ereport(WARNING,
+					(errmsg("could not detach from shared memory segment: %m"),
+			errdetail("Failed system call was munmap(addr=%p, len=%lu).",
+					  ShmemSegmentAddress, (unsigned long) ShmemSegmentSize)));
+		if (ShmemFileDescriptor != -1)
+			close(ShmemFileDescriptor); /* XXX may fail, not important */
+		ShmemSegmentAddress = NULL;
+		ShmemSegmentSize = 0;
+		ShmemFileDescriptor = -1;
+	}
+}
Index: src/backend/port/pipe_sema.c
===================================================================
RCS file: src/backend/port/pipe_sema.c
diff -N src/backend/port/pipe_sema.c
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/backend/port/pipe_sema.c	4 May 2005 13:07:11 -0000
@@ -0,0 +1,303 @@
+/*-------------------------------------------------------------------------
+ *
+ * pipe_sema.c
+ *	  Implement PGSemaphores using pipes
+ *
+ *
+ * Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * IDENTIFICATION
+ *	  $PostgreSQL$
+ *
+ *-------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include <errno.h>
+#include <fcntl.h>
+#include <signal.h>
+#include <unistd.h>
+
+#include "miscadmin.h"
+#include "storage/ipc.h"
+#include "storage/pg_sema.h"
+
+static const char SemaphoreData = 'U';
+static PGSemaphore SemaphoreListHead;
+
+static void
+PGSemaphoreDestroy(int code, Datum arg)
+{
+	while (SemaphoreListHead != NULL) {
+		close(SemaphoreListHead->semPipe[0]);
+		close(SemaphoreListHead->semPipe[1]);
+		SemaphoreListHead->semPipe[0] = SemaphoreListHead->semPipe[1] = -1;
+		SemaphoreListHead = SemaphoreListHead->next;
+	}
+}
+
+/*
+ * Module initialization (called during postmaster start or shmem reinit)
+ */
+void
+PGReserveSemaphores(int maxSemas, int port)
+{
+	ereport(DEBUG4,
+			(errmsg("initializing semaphores")));
+	on_shmem_exit(PGSemaphoreDestroy, 0);
+}
+
+/*
+ * Initialize a PGSemaphore structure to represent a sema with count 1
+ */
+void
+PGSemaphoreCreate(PGSemaphore sema)
+{
+	/* open the pipe */
+	if (pipe(sema->semPipe) != 0)
+		ereport(FATAL,
+				(errmsg("could not create semaphore: %m"),
+		errdetail("Failed system call was pipe().")));
+	/* set the read side non-blocking so we can implement TryLock */
+	/*
+	 * We could leave this out and set O_NONBLOCK only when we need it,
+	 * i.e. in PGSemaphoreTryLock(), but I'm unsure about the consequences
+	 * if two processes share a semaphore and one sets it non-blocking; is
+	 * the flag set for both processes?  For now, assume the read side is
+	 * always non-blocking, until I have time to check SUSv3.
+	 */
+	if (fcntl(sema->semPipe[0], F_SETFL, O_NONBLOCK) != 0)
+		ereport(FATAL,
+				(errmsg("could not create semaphore: %m"),
+		errdetail("Failed system call was fcntl(fildes=%d, cmd=0%o, arg=0%o).",
+				  sema->semPipe[0], F_SETFL, O_NONBLOCK)));
+	ereport(DEBUG4,
+			(errmsg("semaphore created: r%dw%d",
+					sema->semPipe[0], sema->semPipe[1])));
+
+	/* keep track */
+	sema->next = SemaphoreListHead;
+	SemaphoreListHead = sema;
+
+	/* bump */
+	PGSemaphoreUnlock(sema);
+}
+
+/*
+ * Reset a previously-initialized PGSemaphore to have count 0
+ */
+void
+PGSemaphoreReset(PGSemaphore sema)
+{
+	ssize_t rlen;
+	char data;
+
+	Assert(SemaphoreListHead != NULL &&
+		   sema->semPipe[0] >= 0 && sema->semPipe[1] >= 0 &&
+		   sema->semPipe[0] != sema->semPipe[1]);
+	ereport(DEBUG4,
+			(errmsg("resetting semaphore r%dw%d",
+					sema->semPipe[0], sema->semPipe[1])));
+	for (;;) {
+		rlen = read(sema->semPipe[0], &data, 1);
+		switch (rlen) {
+			case 1:
+				/* go on */
+				Assert(data == SemaphoreData);
+				break;
+			case 0:
+				/* done */
+				ereport(DEBUG4,
+						(errmsg("reset semaphore r%dw%d",
+								sema->semPipe[0], sema->semPipe[1])));
+				return;
+			case -1:
+				switch (errno) {
+#ifdef EAGAIN
+					case EAGAIN:
+#endif
+#if defined(EWOULDBLOCK) && (!defined(EAGAIN) || (EWOULDBLOCK != EAGAIN))
+					case EWOULDBLOCK:
+#endif
+						/* done */
+						ereport(DEBUG4,
+								(errmsg("reset semaphore r%dw%d",
+										sema->semPipe[0], sema->semPipe[1])));
+						return;
+					case EINTR:
+						/* try again */
+						break;
+					default:
+						/* oops! */
+						ereport(FATAL,
+								(errmsg("could not reset semaphore: %m"),
+						errdetail("Failed system call was read(fildes=%d, buf=%p, nbyte=%d).",
+								  sema->semPipe[0], &data, 1)));
+						break;
+				}
+				break;
+			default:
+				ereport(PANIC,
+						(errmsg("read on semaphore returned %ld", (long)rlen)));
+		}
+	}
+}
+
+/*
+ * Lock a semaphore (decrement count), blocking if count would be < 0
+ */
+void
+PGSemaphoreLock(PGSemaphore sema, bool interruptOK)
+{
+	fd_set fds, rfds;
+	ssize_t rlen;
+	char data;
+
+	Assert(SemaphoreListHead != NULL &&
+		   sema->semPipe[0] >= 0 && sema->semPipe[1] >= 0 &&
+		   sema->semPipe[0] != sema->semPipe[1]);
+	ereport(DEBUG4,
+			(errmsg("locking semaphore r%dw%d",
+					sema->semPipe[0], sema->semPipe[1])));
+	FD_ZERO(&fds);
+	FD_SET(sema->semPipe[0], &fds);
+	for (;;) {
+		/*
+		 * See the corresponding function in sysv_sema.c for a detailed
+		 * explanation of the interrupt handling.
+		 */
+		ImmediateInterruptOK = interruptOK;
+		CHECK_FOR_INTERRUPTS();
+		rlen = read(sema->semPipe[0], &data, 1);
+		ImmediateInterruptOK = false;
+		switch (rlen) {
+			case 1:
+				Assert(data == SemaphoreData);
+				ereport(DEBUG4,
+						(errmsg("locked semaphore r%dw%d",
+								sema->semPipe[0], sema->semPipe[1])));
+				return;
+			case -1:
+				switch (errno) {
+#ifdef EAGAIN
+					case EAGAIN:
+#endif
+#if defined(EWOULDBLOCK) && (!defined(EAGAIN) || (EWOULDBLOCK != EAGAIN))
+					case EWOULDBLOCK:
+#endif
+						/* wait, and try again */
+						rfds = fds;
+						select(sema->semPipe[0] + 1, &rfds, NULL, NULL, NULL);
+						break;
+					case EINTR:
+						/* try again */
+						break;
+					default:
+						/* oops! */
+						ereport(FATAL,
+								(errmsg("could not decrement semaphore: %m"),
+						errdetail("Failed system call was read(fildes=%d, buf=%p, nbyte=%d).",
+								  sema->semPipe[0], &data, 1)));
+						break;
+				}
+				break;
+			default:
+				ereport(PANIC,
+						(errmsg("short read on semaphore")));
+		}
+	}
+}
+
+/*
+ * Unlock a semaphore (increment count)
+ */
+void
+PGSemaphoreUnlock(PGSemaphore sema)
+{
+	void (*osig)(int);
+	ssize_t wlen;
+
+	Assert(SemaphoreListHead != NULL &&
+		   sema->semPipe[0] >= 0 && sema->semPipe[1] >= 0 &&
+		   sema->semPipe[0] != sema->semPipe[1]);
+	ereport(DEBUG4,
+			(errmsg("unlocking semaphore r%dw%d",
+					sema->semPipe[0], sema->semPipe[1])));
+	osig = signal(SIGPIPE, SIG_IGN);
+	wlen = write(sema->semPipe[1], &SemaphoreData, 1);
+	signal(SIGPIPE, osig);
+	switch (wlen) {
+		case 1:
+			/* done */
+			ereport(DEBUG4,
+					(errmsg("unlocked semaphore r%dw%d",
+							sema->semPipe[0], sema->semPipe[1])));
+			return;
+		case -1:
+			/* failed */
+			ereport(FATAL,
+					(errmsg("could not increment semaphore: %m"),
+			errdetail("Failed system call was write(fildes=%d, buf=%p, nbyte=%d).",
+					  sema->semPipe[1], &SemaphoreData, 1)));
+		default:
+			ereport(PANIC,
+					(errmsg("short write on semaphore")));
+	}
+}
+
+/*
+ * Lock a semaphore only if able to do so without blocking
+ */
+bool
+PGSemaphoreTryLock(PGSemaphore sema)
+{
+	ssize_t rlen;
+	char data;
+
+	Assert(SemaphoreListHead != NULL &&
+		   sema->semPipe[0] >= 0 && sema->semPipe[1] >= 0 &&
+		   sema->semPipe[0] != sema->semPipe[1]);
+	ereport(DEBUG4,
+			(errmsg("trying to lock semaphore r%dw%d",
+					sema->semPipe[0], sema->semPipe[1])));
+	for (;;) {
+		rlen = read(sema->semPipe[0], &data, 1);
+		switch (rlen) {
+			case 1:
+				Assert(data == SemaphoreData);
+				ereport(DEBUG4,
+						(errmsg("locked semaphore r%dw%d",
+								sema->semPipe[0], sema->semPipe[1])));
+				return true;
+			case -1:
+				switch (errno) {
+#ifdef EAGAIN
+					case EAGAIN:
+#endif
+#if defined(EWOULDBLOCK) && (!defined(EAGAIN) || (EWOULDBLOCK != EAGAIN))
+					case EWOULDBLOCK:
+#endif
+						/* failed */
+						ereport(DEBUG4,
+								(errmsg("failed to lock semaphore r%dw%d",
+										sema->semPipe[0], sema->semPipe[1])));
+						return false;
+					case EINTR:
+						/* try again */
+						break;
+					default:
+						/* oops! */
+						ereport(FATAL,
+								(errmsg("could not decrement semaphore: %m"),
+						errdetail("Failed system call was read(fildes=%d, buf=%p, nbyte=%d).",
+								  sema->semPipe[0], &data, 1)));
+						break;
+				}
+				break;
+			default:
+				ereport(PANIC,
+						(errmsg("short read on semaphore")));
+		}
+	}
+}
Index: src/include/pg_config.h.in
===================================================================
RCS file: /home/pqcvs/pgsql/src/include/pg_config.h.in,v
retrieving revision 1.82
diff -u -u -r1.82 pg_config.h.in
--- src/include/pg_config.h.in	11 Mar 2005 17:20:34 -0000	1.82
+++ src/include/pg_config.h.in	4 May 2005 11:40:52 -0000
@@ -639,12 +639,18 @@
    (--enable-integer-datetimes) */
 #undef USE_INTEGER_DATETIMES
 
+/* Define to 1 to select mmap()-based shared memory */
+#undef USE_MMAP_SHARED_MEMORY
+
 /* Define to select named POSIX semaphores. */
 #undef USE_NAMED_POSIX_SEMAPHORES
 
 /* Define to 1 to build with PAM support. (--with-pam) */
 #undef USE_PAM
 
+/* Define to 1 to select pipe()-based semaphores */
+#undef USE_PIPE_SEMAPHORES
+
 /* Define to 1 to build with Rendezvous support. (--with-rendezvous) */
 #undef USE_RENDEZVOUS
 
Index: src/include/storage/pg_sema.h
===================================================================
RCS file: /home/pqcvs/pgsql/src/include/storage/pg_sema.h,v
retrieving revision 1.7
diff -u -u -r1.7 pg_sema.h
--- src/include/storage/pg_sema.h	31 Dec 2004 22:03:42 -0000	1.7
+++ src/include/storage/pg_sema.h	4 May 2005 12:48:19 -0000
@@ -54,6 +54,14 @@
 } PGSemaphoreData;
 #endif
 
+#ifdef USE_PIPE_SEMAPHORES
+typedef struct PGSemaphoreData
+{
+	int			semPipe[2];		/* pipe descriptor set */
+	struct PGSemaphoreData *next;
+} PGSemaphoreData;
+#endif
+
 typedef PGSemaphoreData *PGSemaphore;
 
 
Index: src/template/freebsd
===================================================================
RCS file: /home/pqcvs/pgsql/src/template/freebsd,v
retrieving revision 1.34
diff -u -u -r1.34 freebsd
--- src/template/freebsd	2 Dec 2004 18:11:40 -0000	1.34
+++ src/template/freebsd	4 May 2005 11:32:16 -0000
@@ -1,3 +1,6 @@
 case $host_cpu in
   alpha*)   CFLAGS="-O";;  # alpha has problems with -O2
 esac
+
+USE_PIPE_SEMAPHORES=1
+USE_MMAP_SHARED_MEMORY=1
Index: src/template/linux
===================================================================
RCS file: /home/pqcvs/pgsql/src/template/linux,v
retrieving revision 1.27
diff -u -u -r1.27 linux
--- src/template/linux	2 Dec 2004 18:11:40 -0000	1.27
+++ src/template/linux	4 May 2005 11:32:30 -0000
@@ -1,2 +1,5 @@
 # Force _GNU_SOURCE on; plperl is broken with Perl 5.8.0 otherwise
 CPPFLAGS="-D_GNU_SOURCE"
+
+USE_PIPE_SEMAPHORES=1
+USE_MMAP_SHARED_MEMORY=1