PostgreSQL works again on Mac OS X 10.1. Hold your nose before

investigating the kluge that makes it so...

src/backend/port/darwin/Makefile

@@ -4,7 +4,7 @@
 #    Makefile for port/darwin
 #
 # IDENTIFICATION
-#    $Header: /cvsroot/pgsql/src/backend/port/darwin/Makefile,v 1.1 2000/12/11 00:49:54 tgl Exp $
+#    $Header: /cvsroot/pgsql/src/backend/port/darwin/Makefile,v 1.2 2001/11/08 04:24:03 tgl Exp $
 #
 #-------------------------------------------------------------------------
 
@@ -12,7 +12,7 @@ subdir = src/backend/port/darwin
 top_builddir = ../../../..
 include $(top_builddir)/src/Makefile.global
 
-OBJS = sem.o
+OBJS = sem.o system.o
 
 all: SUBSYS.o
 

src/backend/port/darwin/README

+The file system.c included herein is taken directly from Apple's Darwin
+open-source CVS archives, and is redistributed under the BSD copyright
+notice it bears.  (According to Apple's CVS logs, their version is
+identical to the FreeBSD original.)  It provides our own implementation of
+the system(3) function, which ought by all rights to be identical to the
+one provided in libc on Darwin machines.  Nonetheless, this version works,
+whereas the one that actually ships with Mac OS X 10.1 doesn't.  The
+shipped version appears to disconnect the calling process from any shared
+memory segments it is attached to.  (The symptom seen in PostgreSQL is
+that a backend attempting to execute CREATE DATABASE core-dumps.)  I would
+love to know why there is a discrepancy between the published source and
+the actual behavior --- tgl 7-Nov-2001.
+
+Appropriate bug reports have been filed with Apple --- see 
+Radar Bug#s 2767956, 2683531, 2805147.  One hopes we can retire this
+kluge in the not too distant future.
+
+
+As of PostgreSQL 7.2 and Mac OS X 10.1, one should expect warnings
+like these while linking the backend:
+
+/usr/bin/ld: warning unused multiple definitions of symbol _system
+port/SUBSYS.o definition of _system in section (__TEXT,__text)
+/usr/lib/libm.dylib(system.o) unused definition of _system
+/usr/bin/ld: warning unused multiple definitions of symbol _semctl
+port/SUBSYS.o definition of _semctl in section (__TEXT,__text)
+/usr/lib/libm.dylib(semctl.o) unused definition of _semctl
+/usr/bin/ld: warning unused multiple definitions of symbol _semget
+port/SUBSYS.o definition of _semget in section (__TEXT,__text)
+/usr/lib/libm.dylib(semget.o) unused definition of _semget
+/usr/bin/ld: warning unused multiple definitions of symbol _semop
+port/SUBSYS.o definition of _semop in section (__TEXT,__text)
+/usr/lib/libm.dylib(semop.o) unused definition of _semop
+
+The first of these shows us overriding system() per the above-described
+hack.  The rest show sem.c overriding the nonfunctional semaphore stubs
+in libc.  (Perhaps sem.c can also be retired someday, but semget support
+is reportedly not high on Apple's to-do list.)

src/backend/port/darwin/system.c

+/*
+ * Copyright (c) 1988, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD: src/lib/libc/stdlib/system.c,v 1.6 2000/03/16 02:14:41 jasone Exp $
+ */
+
+#if defined(LIBC_SCCS) && !defined(lint)
+static char sccsid[] = "@(#)system.c	8.1 (Berkeley) 6/4/93";
+#endif /* LIBC_SCCS and not lint */
+
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <signal.h>
+#include <stdlib.h>
+#include <stddef.h>
+#include <unistd.h>
+#include <paths.h>
+#include <errno.h>
+
+int system(const char *command);
+
+int
+system(const char *command)
+{
+	pid_t pid;
+	int pstat;
+	struct sigaction ign, intact, quitact;
+	sigset_t newsigblock, oldsigblock;
+
+	if (!command)		/* just checking... */
+		return(1);
+
+	/*
+	 * Ignore SIGINT and SIGQUIT, block SIGCHLD. Remember to save
+	 * existing signal dispositions.
+	 */
+	ign.sa_handler = SIG_IGN;
+	(void)sigemptyset(&ign.sa_mask);
+	ign.sa_flags = 0;
+	(void)sigaction(SIGINT, &ign, &intact);
+	(void)sigaction(SIGQUIT, &ign, &quitact);
+	(void)sigemptyset(&newsigblock);
+	(void)sigaddset(&newsigblock, SIGCHLD);
+	(void)sigprocmask(SIG_BLOCK, &newsigblock, &oldsigblock);
+	switch(pid = fork()) {
+	case -1:			/* error */
+		break;
+	case 0:				/* child */
+		/*
+		 * Restore original signal dispositions and exec the command.
+		 */
+		(void)sigaction(SIGINT, &intact, NULL);
+		(void)sigaction(SIGQUIT,  &quitact, NULL);
+		(void)sigprocmask(SIG_SETMASK, &oldsigblock, NULL);
+		execl(_PATH_BSHELL, "sh", "-c", command, (char *)NULL);
+		_exit(127);
+	default:			/* parent */
+		do {
+			pid = wait4(pid, &pstat, 0, (struct rusage *)0);
+		} while (pid == -1 && errno == EINTR);
+		break;
+	}
+	(void)sigaction(SIGINT, &intact, NULL);
+	(void)sigaction(SIGQUIT,  &quitact, NULL);
+	(void)sigprocmask(SIG_SETMASK, &oldsigblock, NULL);
+	return(pid == -1 ? -1 : pstat);
+}