This is needed to enforce correct semantics of mkostemp_safer.
Meanwhile, it is one step closer to providing O_CLOEXEC support
to open, as well as implementing portions of fcntl for mingw.
* lib/cloexec.h (dup_cloexec): New prototype. Add copyright
header and comments.
* lib/cloexec.c (set_cloexec_flag): Add comments.
(dup_cloexec): New function, with mingw implementation borrowed
from...
* lib/w32spawn.h (dup_noinherit): ...here.
* modules/execute (Depends-on): Add cloexec.
* modules/pipe (Depends-on): Likewise.
* modules/cloexec (Depends-on): Add dup2.
* modules/cloexec-tests (Files): New file.
* tests/test-cloexec.c: Likewise.
Signed-off-by: Eric Blake <ebb9@byu.net>
2009-12-05 Eric Blake <ebb9@byu.net>
+ cloexec: add dup_cloexec
+ * lib/cloexec.h (dup_cloexec): New prototype. Add copyright
+ header and comments.
+ * lib/cloexec.c (set_cloexec_flag): Add comments.
+ (dup_cloexec): New function, with mingw implementation borrowed
+ from...
+ * lib/w32spawn.h (dup_noinherit): ...here.
+ * modules/execute (Depends-on): Add cloexec.
+ * modules/pipe (Depends-on): Likewise.
+ * modules/cloexec (Depends-on): Add dup2.
+ * modules/cloexec-tests (Files): New file.
+ * tests/test-cloexec.c: Likewise.
+
test-xalloc-die: fix test for mingw
* modules/xalloc-die-tests (Files): Add tests/init.sh.
* tests/test-xalloc-die.sh: Rewrite to use init.sh. Strip
/* closexec.c - set or clear the close-on-exec descriptor flag
- Copyright (C) 1991, 2004, 2005, 2006 Free Software Foundation, Inc.
+ Copyright (C) 1991, 2004, 2005, 2006, 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
#include "cloexec.h"
-#include <unistd.h>
+#include <errno.h>
#include <fcntl.h>
+#include <unistd.h>
+
+#if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
+/* Native Woe32 API. */
+# define WIN32_LEAN_AND_MEAN
+# include <windows.h>
+# include <io.h>
+#endif
+
/* Set the `FD_CLOEXEC' flag of DESC if VALUE is true,
or clear the flag if VALUE is false.
- Return 0 on success, or -1 on error with `errno' set. */
+ Return 0 on success, or -1 on error with `errno' set.
+
+ Note that on MingW, this function does NOT protect DESC from being
+ inherited into spawned children. Instead, either use dup_cloexec
+ followed by closing the original DESC, or use interfaces such as
+ open or pipe2 that accept flags like O_CLOEXEC to create DESC
+ non-inheritable in the first place. */
int
set_cloexec_flag (int desc, bool value)
int newflags = (value ? flags | FD_CLOEXEC : flags & ~FD_CLOEXEC);
if (flags == newflags
- || fcntl (desc, F_SETFD, newflags) != -1)
- return 0;
+ || fcntl (desc, F_SETFD, newflags) != -1)
+ return 0;
}
return -1;
#else
- return 0;
+ if (desc < 0)
+ {
+ errno = EBADF;
+ return -1;
+ }
+ return dup2 (desc, desc) == desc ? 0 : -1;
#endif
}
+
+
+/* Duplicates a file handle FD, while marking the copy to be closed
+ prior to exec or spawn. Returns -1 and sets errno if FD could not
+ be duplicated. */
+
+int dup_cloexec (int fd)
+{
+ int nfd;
+
+#if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
+
+ /* Native Woe32 API. */
+ HANDLE curr_process = GetCurrentProcess ();
+ HANDLE old_handle = (HANDLE) _get_osfhandle (fd);
+ HANDLE new_handle;
+
+ if (old_handle == INVALID_HANDLE_VALUE)
+ {
+ /* fd is closed, or is open to no handle at all.
+ We cannot duplicate fd in this case, because _open_osfhandle
+ fails for an INVALID_HANDLE_VALUE argument. */
+ errno = EBADF;
+ return -1;
+ }
+
+ if (!DuplicateHandle (curr_process, /* SourceProcessHandle */
+ old_handle, /* SourceHandle */
+ curr_process, /* TargetProcessHandle */
+ (PHANDLE) &new_handle, /* TargetHandle */
+ (DWORD) 0, /* DesiredAccess */
+ FALSE, /* InheritHandle */
+ DUPLICATE_SAME_ACCESS)) /* Options */
+ {
+ errno = EMFILE;
+ return -1;
+ }
+
+ nfd = _open_osfhandle ((long) new_handle, O_BINARY | O_NOINHERIT);
+ if (nfd < 0)
+ {
+ CloseHandle (new_handle);
+ errno = EMFILE;
+ return -1;
+ }
+
+# if REPLACE_FCHDIR
+ if (0 <= nfd)
+ result = _gl_register_dup (fd, nfd);
+# endif
+ return nfd;
+
+#else /* !_WIN32 */
+
+ /* Unix API. */
+
+# ifdef F_DUPFD_CLOEXEC
+ nfd = fcntl (fd, F_DUPFD_CLOEXEC, 0);
+# if REPLACE_FCHDIR
+ if (0 <= nfd)
+ result = _gl_register_dup (fd, nfd);
+# endif
+
+# else /* !F_DUPFD_CLOEXEC */
+ nfd = dup (fd);
+ if (0 <= nfd && set_cloexec_flag (nfd, true))
+ {
+ int saved_errno = errno;
+ close (nfd);
+ nfd = -1;
+ errno = saved_errno;
+ }
+# endif /* !F_DUPFD_CLOEXEC */
+
+ return nfd;
+
+#endif /* !_WIN32 */
+}
+/* closexec.c - set or clear the close-on-exec descriptor flag
+
+ Copyright (C) 2004, 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/>.
+
+*/
+
#include <stdbool.h>
+
+/* Set the `FD_CLOEXEC' flag of DESC if VALUE is true,
+ or clear the flag if VALUE is false.
+ Return 0 on success, or -1 on error with `errno' set.
+
+ Note that on MingW, this function does NOT protect DESC from being
+ inherited into spawned children. Instead, either use dup_cloexec
+ followed by closing the original DESC, or use interfaces such as
+ open or pipe2 that accept flags like O_CLOEXEC to create DESC
+ non-inheritable in the first place. */
+
int set_cloexec_flag (int desc, bool value);
+
+/* Duplicates a file handle FD, while marking the copy to be closed
+ prior to exec or spawn. Returns -1 and sets errno if FD could not
+ be duplicated. */
+
+int dup_cloexec (int fd);
#include <unistd.h>
#include <errno.h>
+#include "cloexec.h"
#include "xalloc.h"
/* Duplicates a file handle, making the copy uninheritable.
static int
dup_noinherit (int fd)
{
- HANDLE curr_process = GetCurrentProcess ();
- HANDLE old_handle = (HANDLE) _get_osfhandle (fd);
- HANDLE new_handle;
- int nfd;
-
- if (old_handle == INVALID_HANDLE_VALUE)
- /* fd is closed, or is open to no handle at all.
- We cannot duplicate fd in this case, because _open_osfhandle fails for
- an INVALID_HANDLE_VALUE argument. */
- return -1;
-
- if (!DuplicateHandle (curr_process, /* SourceProcessHandle */
- old_handle, /* SourceHandle */
- curr_process, /* TargetProcessHandle */
- (PHANDLE) &new_handle, /* TargetHandle */
- (DWORD) 0, /* DesiredAccess */
- FALSE, /* InheritHandle */
- DUPLICATE_SAME_ACCESS)) /* Options */
- error (EXIT_FAILURE, 0, _("DuplicateHandle failed with error code 0x%08x"),
- (unsigned int) GetLastError ());
-
- nfd = _open_osfhandle ((long) new_handle, O_BINARY | O_NOINHERIT);
- if (nfd < 0)
+ fd = dup_cloexec (fd);
+ if (fd < 0 && errno == EMFILE)
error (EXIT_FAILURE, errno, _("_open_osfhandle failed"));
- return nfd;
+ return fd;
}
/* Returns a file descriptor equivalent to FD, except that the resulting file
m4/cloexec.m4
Depends-on:
+dup2
stdbool
configure.ac:
--- /dev/null
+Files:
+tests/test-cloexec.c
+
+Depends-on:
+
+configure.ac:
+
+Makefile.am:
+TESTS += test-cloexec
+check_PROGRAMS += test-cloexec
m4/execute.m4
Depends-on:
+cloexec
dup2
error
exit
m4/pipe.m4
Depends-on:
+cloexec
dup2
environ
error
--- /dev/null
+/* Test duplicating non-inheritable file descriptors.
+ 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>
+
+#include "cloexec.h"
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
+/* Get declarations of the Win32 API functions. */
+# define WIN32_LEAN_AND_MEAN
+# include <windows.h>
+#endif
+
+#define ASSERT(expr) \
+ do \
+ { \
+ if (!(expr)) \
+ { \
+ fprintf (stderr, "%s:%d: assertion failed\n", __FILE__, __LINE__); \
+ fflush (stderr); \
+ abort (); \
+ } \
+ } \
+ while (0)
+
+/* Return non-zero if FD is open and inheritable across exec/spawn. */
+static int
+is_inheritable (int fd)
+{
+#if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
+ /* On Win32, the initial state of unassigned standard file
+ descriptors is that they are open but point to an
+ INVALID_HANDLE_VALUE, and there is no fcntl. */
+ HANDLE h = (HANDLE) _get_osfhandle (fd);
+ DWORD flags;
+ if (h == INVALID_HANDLE_VALUE || GetHandleInformation (h, &flags) == 0)
+ return 0;
+ return (flags & HANDLE_FLAG_INHERIT) != 0;
+#else
+# ifndef F_GETFD
+# error Please port fcntl to your platform
+# endif
+ int i = fcntl (fd, F_GETFD);
+ return 0 <= i && (i & FD_CLOEXEC) == 0;
+#endif
+}
+
+int
+main (void)
+{
+ const char *file = "test-cloexec.tmp";
+ int fd = creat (file, 0600);
+ int fd2;
+
+ /* Assume std descriptors were provided by invoker. */
+ ASSERT (STDERR_FILENO < fd);
+ ASSERT (is_inheritable (fd));
+
+ /* Normal use of set_cloexec_flag. */
+ ASSERT (set_cloexec_flag (fd, true) == 0);
+#if !((defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__)
+ ASSERT (!is_inheritable (fd));
+#endif
+ ASSERT (set_cloexec_flag (fd, false) == 0);
+ ASSERT (is_inheritable (fd));
+
+ /* Normal use of dup_cloexec. */
+ fd2 = dup_cloexec (fd);
+ ASSERT (fd < fd2);
+ ASSERT (!is_inheritable (fd2));
+ ASSERT (close (fd) == 0);
+ ASSERT (dup_cloexec (fd2) == fd);
+ ASSERT (!is_inheritable (fd));
+ ASSERT (close (fd2) == 0);
+
+ /* Test error handling. */
+ errno = 0;
+ ASSERT (set_cloexec_flag (-1, false) == -1);
+ ASSERT (errno == EBADF);
+ errno = 0;
+ ASSERT (set_cloexec_flag (10000000, false) == -1);
+ ASSERT (errno == EBADF);
+ errno = 0;
+ ASSERT (set_cloexec_flag (fd2, false) == -1);
+ ASSERT (errno == EBADF);
+ errno = 0;
+ ASSERT (dup_cloexec (-1) == -1);
+ ASSERT (errno == EBADF);
+ errno = 0;
+ ASSERT (dup_cloexec (10000000) == -1);
+ ASSERT (errno == EBADF);
+ errno = 0;
+ ASSERT (dup_cloexec (fd2) == -1);
+ ASSERT (errno == EBADF);
+
+ /* Clean up. */
+ ASSERT (close (fd) == 0);
+ ASSERT (unlink (file) == 0);
+
+ return 0;
+}
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