From owner-svn-src-head@FreeBSD.ORG Tue Aug 13 20:38:56 2013 Return-Path: Delivered-To: svn-src-head@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTP id 9E4BF70A; Tue, 13 Aug 2013 20:38:56 +0000 (UTC) (envelope-from peter@FreeBSD.org) Received: from svn.freebsd.org (svn.freebsd.org [IPv6:2001:1900:2254:2068::e6a:0]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.freebsd.org (Postfix) with ESMTPS id 7285A23B4; Tue, 13 Aug 2013 20:38:56 +0000 (UTC) Received: from svn.freebsd.org ([127.0.1.70]) by svn.freebsd.org (8.14.7/8.14.7) with ESMTP id r7DKcutt082571; Tue, 13 Aug 2013 20:38:56 GMT (envelope-from peter@svn.freebsd.org) Received: (from peter@localhost) by svn.freebsd.org (8.14.7/8.14.5/Submit) id r7DKcuH7082570; Tue, 13 Aug 2013 20:38:56 GMT (envelope-from peter@svn.freebsd.org) Message-Id: <201308132038.r7DKcuH7082570@svn.freebsd.org> From: Peter Wemm Date: Tue, 13 Aug 2013 20:38:56 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r254297 - head/lib/libc/stdlib X-SVN-Group: head MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 13 Aug 2013 20:38:56 -0000 Author: peter Date: Tue Aug 13 20:38:55 2013 New Revision: 254297 URL: http://svnweb.freebsd.org/changeset/base/254297 Log: vfork(2) was listed as deprecated in 1994 (r1573) and was the false reports of its impending demise were removed in 2009 (r199257). However, in 1996 (r16117) system(3) was switched from vfork(2) to fork(2) based partly on this. Switch back to vfork(2). This has a dramatic effect in cases of extreme mmap use - such as excessive abuse (500+) of shared libraries. popen(3) has used vfork(2) for a while. vfork(2) isn't going anywhere. Modified: head/lib/libc/stdlib/system.c Modified: head/lib/libc/stdlib/system.c ============================================================================== --- head/lib/libc/stdlib/system.c Tue Aug 13 20:33:50 2013 (r254296) +++ head/lib/libc/stdlib/system.c Tue Aug 13 20:38:55 2013 (r254297) @@ -39,6 +39,7 @@ __FBSDID("$FreeBSD$"); #include #include #include +#include #include #include #include @@ -56,37 +57,36 @@ __system(const char *command) 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()) { + switch(pid = vfork()) { case -1: /* error */ - break; + (void)_sigprocmask(SIG_SETMASK, &oldsigblock, NULL); + return (-1); 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 */ - savedpid = pid; - do { - pid = _wait4(savedpid, &pstat, 0, (struct rusage *)0); - } while (pid == -1 && errno == EINTR); - break; } + /* + * If we are running means that the child has either completed + * its execve, or has failed. + * Block SIGINT/QUIT because sh -c handles it and wait for + * it to clean up. + */ + memset(&ign, 0, sizeof(ign)); + ign.sa_handler = SIG_IGN; + (void)sigemptyset(&ign.sa_mask); + (void)_sigaction(SIGINT, &ign, &intact); + (void)_sigaction(SIGQUIT, &ign, &quitact); + savedpid = pid; + do { + pid = _wait4(savedpid, &pstat, 0, (struct rusage *)0); + } while (pid == -1 && errno == EINTR); (void)_sigaction(SIGINT, &intact, NULL); (void)_sigaction(SIGQUIT, &quitact, NULL); (void)_sigprocmask(SIG_SETMASK, &oldsigblock, NULL);