* doc/posix-functions/popen.texi (popen): Document cygwin bugs.
* modules/popen: New file.
* modules/popen-tests: Likewise.
* tests/test-popen.c: Likewise.
* m4/popen.m4: Likewise.
* lib/popen.c: Likewise.
* lib/stdio.in.h (popen): New declaration.
* m4/stdio_h.m4 (gl_STDIO_H_DEFAULTS): Add popen.
* modules/stdio (Makefile.am): Likewise.
* MODULES.html.sh (systems lacking POSIX:2008): Mention it.
Signed-off-by: Eric Blake <ebb9@byu.net>
+2009-08-19 Eric Blake <ebb9@byu.net>
+
+ popen: fix cygwin 1.5 bug when stdin closed
+ * doc/posix-functions/popen.texi (popen): Document cygwin bugs.
+ * modules/popen: New file.
+ * modules/popen-tests: Likewise.
+ * tests/test-popen.c: Likewise.
+ * m4/popen.m4: Likewise.
+ * lib/popen.c: Likewise.
+ * lib/stdio.in.h (popen): New declaration.
+ * m4/stdio_h.m4 (gl_STDIO_H_DEFAULTS): Add popen.
+ * modules/stdio (Makefile.am): Likewise.
+ * MODULES.html.sh (systems lacking POSIX:2008): Mention it.
+
2009-08-17 Joel E. Denny <jdenny@clemson.edu>
maint.mk: give full control over update-copyright exclusions
func_module open
func_module perror
func_module poll
+ func_module popen
func_module posix_spawn
func_module posix_spawnattr_destroy
func_module posix_spawnattr_getflags
POSIX specification: @url{http://www.opengroup.org/onlinepubs/9699919799/functions/popen.html}
-Gnulib module: ---
+Gnulib module: popen
Portability problems fixed by Gnulib:
@itemize
+@item
+Some platforms start the child with closed stdin or stdout if the
+standard descriptors were closed in the parent:
+Cygwin 1.5.x.
@end itemize
Portability problems not fixed by Gnulib:
@itemize
+@item
+Some platforms mistakenly set the close-on-exec bit, then if it is
+cleared by the application, the platform then leaks file descriptors
+from earlier @code{popen} calls into subsequent @code{popen} children:
+Cygwin 1.5.x.
@end itemize
--- /dev/null
+/* Open a stream to a sub-process.
+ Copyright (C) 2009 Free Software Foundation, Inc.
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
+
+/* Written by Eric Blake <ebb9@byu.net>, 2009. */
+
+#include <config.h>
+
+/* Get the original definition of popen. It might be defined as a macro. */
+#define __need_FILE
+# include <stdio.h>
+#undef __need_FILE
+
+static inline FILE *
+orig_popen (const char *filename, const char *mode)
+{
+ return popen (filename, mode);
+}
+
+/* Specification. */
+#include <stdio.h>
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+FILE *
+rpl_popen (const char *filename, const char *mode)
+{
+ /* The mingw popen works fine, and all other platforms have fcntl.
+ The bug of the child clobbering its own file descriptors if stdin
+ or stdout was closed in the parent can be worked around by
+ opening those two fds as close-on-exec to begin with. */
+ /* Cygwin 1.5.x also has a bug where the popen fd is improperly
+ marked close-on-exec, and if the application undoes this, then
+ the fd leaks into subsequent popen calls. We could work around
+ this by maintaining a list of all fd's opened by popen, and
+ temporarily marking them cloexec around the real popen call, but
+ we would also have to override pclose, and the bookkeepping seems
+ extreme given that cygwin 1.7 no longer has the bug. */
+ FILE *result;
+ int cloexec0 = fcntl (STDIN_FILENO, F_GETFD);
+ int cloexec1 = fcntl (STDOUT_FILENO, F_GETFD);
+ int saved_errno;
+
+ if (cloexec0 < 0)
+ {
+ if (open ("/dev/null", O_RDONLY) != STDIN_FILENO
+ || fcntl (STDIN_FILENO, F_SETFD,
+ fcntl (STDIN_FILENO, F_GETFD) | FD_CLOEXEC) == -1)
+ abort ();
+ }
+ if (cloexec1 < 0)
+ {
+ if (open ("/dev/null", O_RDONLY) != STDOUT_FILENO
+ || fcntl (STDOUT_FILENO, F_SETFD,
+ fcntl (STDOUT_FILENO, F_GETFD) | FD_CLOEXEC) == -1)
+ abort ();
+ }
+ result = orig_popen (filename, mode);
+ saved_errno = errno;
+ if (cloexec0 < 0)
+ close (STDIN_FILENO);
+ if (cloexec1 < 0)
+ close (STDOUT_FILENO);
+ errno = saved_errno;
+ return result;
+}
extern size_t fwrite (const void *ptr, size_t s, size_t n, FILE *stream);
#endif
+#if @GNULIB_POPEN@
+# if @REPLACE_POPEN@
+# undef popen
+# define popen rpl_popen
+extern FILE *popen (const char *cmd, const char *mode);
+# endif
+#elif defined GNULIB_POSIXCHECK
+# undef popen
+# define popen(c,m) \
+ (GL_LINK_WARNING ("popen is buggy on some platforms - " \
+ "use gnulib module popen or pipe for more portability"), \
+ popen (c, m))
+#endif
+
#if @GNULIB_GETDELIM@
# if !@HAVE_DECL_GETDELIM@
/* Read input, up to (and including) the next occurrence of DELIMITER, from
--- /dev/null
+# popen.m4 serial 1
+dnl Copyright (C) 2009 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_POPEN],
+[
+ AC_REQUIRE([gl_STDIO_H_DEFAULTS])
+ AC_CACHE_CHECK([whether popen works with closed stdin],
+ [gl_cv_func_popen_works],
+ [
+ AC_RUN_IFELSE([AC_LANG_PROGRAM([[#include <stdio.h>
+]], [FILE *child;
+ fclose (stdin);
+ fclose (stdout);
+ child = popen ("echo a", "r");
+ return !(fgetc (child) == 'a' && pclose (child) == 0);
+])], [gl_cv_func_popen_works=yes], [gl_cv_func_popen_works=no],
+ dnl For now, only cygwin 1.5 or older is known to be broken.
+ [gl_cv_func_popen_works='guessing yes'])
+ ])
+ if test "$gl_cv_func_popen_works" = no; then
+ REPLACE_POPEN=1
+ AC_LIBOBJ([popen])
+ gl_PREREQ_POPEN
+ fi
+])
+
+# Prerequisites of lib/popen.c.
+AC_DEFUN([gl_PREREQ_POPEN],
+[
+ AC_REQUIRE([AC_C_INLINE])
+])
-# stdio_h.m4 serial 16
+# stdio_h.m4 serial 17
dnl Copyright (C) 2007-2009 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
GNULIB_FPUTS=0; AC_SUBST([GNULIB_FPUTS])
GNULIB_PUTS=0; AC_SUBST([GNULIB_PUTS])
GNULIB_FWRITE=0; AC_SUBST([GNULIB_FWRITE])
+ GNULIB_POPEN=0; AC_SUBST([GNULIB_POPEN])
GNULIB_GETDELIM=0; AC_SUBST([GNULIB_GETDELIM])
GNULIB_GETLINE=0; AC_SUBST([GNULIB_GETLINE])
GNULIB_PERROR=0; AC_SUBST([GNULIB_PERROR])
REPLACE_FPURGE=0; AC_SUBST([REPLACE_FPURGE])
HAVE_DECL_FPURGE=1; AC_SUBST([HAVE_DECL_FPURGE])
REPLACE_FCLOSE=0; AC_SUBST([REPLACE_FCLOSE])
+ REPLACE_POPEN=0; AC_SUBST([REPLACE_POPEN])
HAVE_DECL_GETDELIM=1; AC_SUBST([HAVE_DECL_GETDELIM])
HAVE_DECL_GETLINE=1; AC_SUBST([HAVE_DECL_GETLINE])
REPLACE_GETLINE=0; AC_SUBST([REPLACE_GETLINE])
--- /dev/null
+Description:
+popen() function: open a stream to a shell command.
+
+Files:
+lib/popen.c
+m4/popen.m4
+
+Depends-on:
+open
+stdio
+
+configure.ac:
+gl_FUNC_POPEN
+gl_STDIO_MODULE_INDICATOR([popen])
+
+Makefile.am:
+
+Include:
+<stdio.h>
+
+License:
+LGPL
+
+Maintainer:
+Eric Blake
--- /dev/null
+Files:
+tests/test-popen.c
+
+Depends-on:
+dup2
+sys_wait
+
+configure.ac:
+
+Makefile.am:
+TESTS += test-popen
+check_PROGRAMS += test-popen
-e 's|@''GNULIB_FPUTS''@|$(GNULIB_FPUTS)|g' \
-e 's|@''GNULIB_PUTS''@|$(GNULIB_PUTS)|g' \
-e 's|@''GNULIB_FWRITE''@|$(GNULIB_FWRITE)|g' \
+ -e 's|@''GNULIB_POPEN''@|$(GNULIB_POPEN)|g' \
-e 's|@''GNULIB_GETDELIM''@|$(GNULIB_GETDELIM)|g' \
-e 's|@''GNULIB_GETLINE''@|$(GNULIB_GETLINE)|g' \
-e 's|@''GNULIB_PERROR''@|$(GNULIB_PERROR)|g' \
-e 's|@''REPLACE_FPURGE''@|$(REPLACE_FPURGE)|g' \
-e 's|@''HAVE_DECL_FPURGE''@|$(HAVE_DECL_FPURGE)|g' \
-e 's|@''REPLACE_FCLOSE''@|$(REPLACE_FCLOSE)|g' \
+ -e 's|@''REPLACE_POPEN''@|$(REPLACE_POPEN)|g' \
-e 's|@''HAVE_DECL_GETDELIM''@|$(HAVE_DECL_GETDELIM)|g' \
-e 's|@''HAVE_DECL_GETLINE''@|$(HAVE_DECL_GETLINE)|g' \
-e 's|@''REPLACE_GETLINE''@|$(REPLACE_GETLINE)|g' \
--- /dev/null
+/* Test of opening a subcommand stream.
+ Copyright (C) 2009 Free Software Foundation, Inc.
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
+
+/* Written by Eric Blake <ebb9@byu.net>, 2009. */
+
+#include <config.h>
+
+/* Specification. */
+#include <stdio.h>
+
+/* Helpers. */
+#include <stdlib.h>
+#include <string.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+#define ASSERT(expr) \
+ do \
+ { \
+ if (!(expr)) \
+ { \
+ fprintf (stderr, "%s:%d: assertion failed\n", __FILE__, __LINE__); \
+ fflush (stderr); \
+ abort (); \
+ } \
+ } \
+ while (0)
+
+int
+main (int argc, char **argv)
+{
+ size_t len;
+ char *cmd;
+ int i;
+
+ /* Children - use the pipe. */
+ if (argc > 1)
+ {
+ if (*argv[1] == 'r') /* Parent is reading, so we write. */
+ ASSERT (putchar ('c') == 'c');
+ else /* Parent is writing, so we read. */
+ ASSERT (getchar () == 'p');
+ /* Test that parent can read non-zero status. */
+ return 42;
+ }
+
+ /* Parent - create read and write child, once under normal
+ circumstances and once with stdin and stdout closed. */
+ len = strlen (argv[0]);
+ cmd = malloc (len + 3); /* Adding " r" and NUL. */
+ ASSERT (cmd);
+ /* We count on argv[0] not containing any shell metacharacters. */
+ strcpy (cmd, argv[0]);
+ cmd[len] = ' ';
+ cmd[len + 2] = '\0';
+ for (i = 0; i < 2; i++)
+ {
+ FILE *child;
+ int status;
+
+ if (i)
+ {
+ ASSERT (fclose (stdin) == 0);
+ ASSERT (fclose (stdout) == 0);
+ }
+
+ cmd[len + 1] = 'r';
+ ASSERT (child = popen (cmd, "r"));
+ ASSERT (fgetc (child) == 'c');
+ status = pclose (child);
+ ASSERT (WIFEXITED (status));
+ ASSERT (WEXITSTATUS (status) == 42);
+ if (i)
+ {
+ ASSERT (dup2 (STDIN_FILENO, STDIN_FILENO) == -1);
+ ASSERT (dup2 (STDOUT_FILENO, STDOUT_FILENO) == -1);
+ }
+
+ cmd[len + 1] = 'w';
+ ASSERT (child = popen (cmd, "w"));
+ ASSERT (fputc ('p', child) == 'p');
+ status = pclose (child);
+ ASSERT (WIFEXITED (status));
+ ASSERT (WEXITSTATUS (status) == 42);
+ if (i)
+ {
+ ASSERT (dup2 (STDIN_FILENO, STDIN_FILENO) == -1);
+ ASSERT (dup2 (STDOUT_FILENO, STDOUT_FILENO) == -1);
+ }
+ }
+ free (cmd);
+ return 0;
+}
projects / gnulib.git / commitdiff