X-Spam-Check-By: sourceware.org Message-ID: <44EB57F0.7020706@byu.net> Date: Tue, 22 Aug 2006 13:16:00 -0600 From: Eric Blake User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.0.5) Gecko/20060719 Thunderbird/1.5.0.5 Mnenhy/0.7.4.666 MIME-Version: 1.0 To: newlib@sources.redhat.com, cygwin@cygwin.com Subject: Re: popen bug [patch] Content-Type: multipart/mixed; boundary="------------010600070205070502020601" X-IsSubscribed: yes Mailing-List: contact cygwin-help@cygwin.com; run by ezmlm List-Subscribe: List-Archive: List-Post: List-Help: , Sender: cygwin-owner@cygwin.com Mail-Followup-To: cygwin@cygwin.com Delivered-To: mailing list cygwin@cygwin.com --------------010600070205070502020601 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 > Cygwin popen does not match Linux popen when stdout is closed. ... > Oops - when stdout is closed, and the pipe is output on child, cygwin > popen mistakenly lost the pipe in both processes. > > > The real world case that found this: > cygwin$ echo 'errprint(esyscmd(echo hi))dnl' | m4 >&- > sh: line 0: echo: write error: Bad file descriptor > > linux$ echo 'errprint(esyscmd(echo hi))dnl' | m4 >&- > hi Fixed as follows, along with a fix to obey POSIX "The popen() function shall ensure that any streams from previous popen() calls that remain open in the parent process are closed in the new child process." 2006-08-22 Eric Blake * libc/posix/popen.c (popen): Don't close output end of pipe in child if stdout was closed on entry. [HAVE_FCNTL]: In parent, mark file as close-on-exec, per POSIX. - -- Life is short - so eat dessert first! Eric Blake ebb9@byu.net -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.2.1 (Cygwin) Comment: Public key at home.comcast.net/~ericblake/eblake.gpg Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFE61fw84KuGfSFAYARArN1AJ0ePKBbffbvvJaJOyW2XlsXUBFixwCffAvM xu28ESQ/Md1uD58Bh77N+V4= =oy2k -----END PGP SIGNATURE----- --------------010600070205070502020601 Content-Type: text/plain; name="newlib.patch3" Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="newlib.patch3" Index: libc/posix/popen.c =================================================================== RCS file: /cvs/src/src/newlib/libc/posix/popen.c,v retrieving revision 1.5 diff -u -p -r1.5 popen.c --- libc/posix/popen.c 6 Jun 2003 19:57:51 -0000 1.5 +++ libc/posix/popen.c 22 Aug 2006 19:13:23 -0000 @@ -1,7 +1,7 @@ /* $NetBSD: popen.c,v 1.11 1995/06/16 07:05:33 jtc Exp $ */ /* - * Copyright (c) 1988, 1993 + * Copyright (c) 1988, 1993, 2006 * The Regents of the University of California. All rights reserved. * * This code is derived from software written by Ken Arnold and @@ -55,6 +55,7 @@ static char rcsid[] = "$NetBSD: popen.c, #include #include #include +#include static struct pid { struct pid *next; @@ -102,7 +103,9 @@ _DEFUN(popen, (program, type), (void)dup2(pdes[1], STDOUT_FILENO); (void)close(pdes[1]); } - (void) close(pdes[0]); + if (pdes[0] != STDOUT_FILENO) { + (void) close(pdes[0]); + } } else { if (pdes[0] != STDIN_FILENO) { (void)dup2(pdes[0], STDIN_FILENO); @@ -129,6 +132,12 @@ _DEFUN(popen, (program, type), (void)close(pdes[0]); } +#ifdef HAVE_FCNTL + /* Hide pipe from future popens; assume fcntl can't fail. */ + fcntl (fileno (iop), F_SETFD, + fcntl (fileno (iop), F_GETFD, 0) | FD_CLOEXEC); +#endif /* HAVE_FCNTL */ + /* Link into list of file descriptors. */ cur->fp = iop; cur->pid = pid; --------------010600070205070502020601 Content-Type: text/plain; charset=us-ascii -- Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple Problem reports: http://cygwin.com/problems.html Documentation: http://cygwin.com/docs.html FAQ: http://cygwin.com/faq/ --------------010600070205070502020601--