Commit 067428c1 authored by Paul Eggert's avatar Paul Eggert
Browse files

Make file descriptors close-on-exec when possible.

This simplifies Emacs a bit, since it no longer needs to worry
about closing file descriptors by hand in some cases.
It also fixes some unlikely races.  Not all such races, as
libraries often open files internally without setting
close-on-exec, but it's an improvement.
* admin/merge-gnulib (GNULIB_MODULES): Add fcntl, pipe2.
(GNULIB_TOOL_FLAGS): Avoid binary-io, close.  Do not avoid fcntl.
* configure.ac (mkostemp): New function to check for.
(PTY_OPEN): Pass O_CLOEXEC to posix_openpt.
* lib/fcntl.c, lib/getdtablesize.c, lib/pipe2.c, m4/fcntl.m4:
* m4/getdtablesize.m4, m4/pipe2.m4: New files, taken from gnulib.
* lib/gnulib.mk, m4/gnulib-comp.m4: Regenerate.
* nt/gnulib.mk: Remove empty gl_GNULIB_ENABLED_verify section;
otherwise, gnulib-tool complains given close-on-exec changes.
* nt/inc/ms-w32.h (pipe): Remove.
* nt/mingw-cfg.site (ac_cv_func_fcntl, gl_cv_func_fcntl_f_dupfd_cloexec)
(gl_cv_func_fcntl_f_dupfd_works, ac_cv_func_pipe2): New vars.
* src/alloc.c (valid_pointer_p) [!WINDOWSNT]:
* src/callproc.c (Fcall_process) [!MSDOS]:
* src/emacs.c (main) [!DOS_NT]:
* src/nsterm.m (ns_term_init):
* src/process.c (create_process):
Use 'pipe2' with O_CLOEXEC instead of 'pipe'.
* src/emacs.c (Fcall_process_region) [HAVE_MKOSTEMP]:
* src/filelock.c (create_lock_file) [HAVE_MKOSTEMP]:
Prefer mkostemp with O_CLOEXEC to mkstemp.
* src/callproc.c (relocate_fd) [!WINDOWSNT]:
* src/emacs.c (main): Use F_DUPFD_CLOEXEC, not plain F_DUPFD.
No need to use fcntl (..., F_SETFD, FD_CLOEXEC), since we're
now using pipe2.
* src/filelock.c (create_lock_file) [! HAVE_MKOSTEMP]:
Make the resulting file descriptor close-on-exec.
* src/lisp.h, src/lread.c, src/process.c (close_load_descs, close_process_descs):
* src/lread.c (load_descriptor_list, load_descriptor_unwind):
Remove; no longer needed.  All uses removed.
* src/process.c (SOCK_CLOEXEC): Define to 0 if not supplied by system.
(close_on_exec, accept4, process_socket) [!SOCK_CLOEXEC]:
New functions.
(socket) [!SOCK_CLOEXEC]: Supply a substitute.
(Fmake_network_process, Fnetwork_interface_list):
(Fnetwork_interface_info, server_accept_connection):
Make newly-created socket close-on-exec.
* src/sysdep.c (emacs_open, emacs_fopen):
Make new-created descriptor close-on-exec.
* src/w32.c (fcntl): Support F_DUPFD_CLOEXEC well enough for Emacs.
* src/w32.c, src/w32.h (pipe2): Rename from 'pipe', with new flags arg.

Fixes: debbugs:14803
parent 9aff9b38
2013-07-07 Paul Eggert <eggert@cs.ucla.edu>
Make file descriptors close-on-exec when possible (Bug#14803).
* configure.ac (mkostemp): New function to check for.
(PTY_OPEN): Pass O_CLOEXEC to posix_openpt.
* lib/fcntl.c, lib/getdtablesize.c, lib/pipe2.c, m4/fcntl.m4:
* m4/getdtablesize.m4, m4/pipe2.m4: New files, taken from gnulib.
* lib/gnulib.mk, m4/gnulib-comp.m4: Regenerate.
2013-07-03 Christoph Egger <christoph@debian.org> (tiny change)
* configure.ac (emacs_broken_SIGIO): Set on gnu-kfreebsd to avoid hang.
......
2013-07-07 Paul Eggert <eggert@cs.ucla.edu>
Make file descriptors close-on-exec when possible (Bug#14803).
* merge-gnulib (GNULIB_MODULES): Add fcntl, pipe2.
(GNULIB_TOOL_FLAGS): Avoid binary-io, close. Do not avoid fcntl.
2013-07-06 Glenn Morris <rgm@gnu.org>
* admin.el (manual-misc-manuals): New function.
......
......@@ -29,11 +29,11 @@ GNULIB_MODULES='
alloca-opt c-ctype c-strcase
careadlinkat close-stream crypto/md5 crypto/sha1 crypto/sha256 crypto/sha512
dtoastr dtotimespec dup2 environ execinfo faccessat
fcntl-h fdatasync fdopendir filemode fstatat fsync
fcntl fcntl-h fdatasync fdopendir filemode fstatat fsync
getloadavg getopt-gnu gettime gettimeofday
ignore-value intprops largefile lstat
manywarnings memrchr mktime
pselect pthread_sigmask putenv qacl readlink readlinkat
pipe2 pselect pthread_sigmask putenv qacl readlink readlinkat
sig2str socklen stat-time stdalign stdarg stdbool stdio
strftime strtoimax strtoumax symlink sys_stat
sys_time time timer-time timespec-add timespec-sub unsetenv utimens
......@@ -41,8 +41,8 @@ GNULIB_MODULES='
'
GNULIB_TOOL_FLAGS='
--avoid=dup
--avoid=fchdir --avoid=fcntl --avoid=fstat
--avoid=binary-io --avoid=close --avoid=dup
--avoid=fchdir --avoid=fstat
--avoid=malloc-posix --avoid=msvc-inval --avoid=msvc-nothrow
--avoid=open --avoid=openat-die --avoid=opendir
--avoid=raise
......
......@@ -3244,7 +3244,7 @@ select getpagesize setlocale \
getrlimit setrlimit shutdown getaddrinfo \
strsignal setitimer \
sendto recvfrom getsockname getpeername getifaddrs freeifaddrs \
gai_strerror mkstemp getline getdelim sync \
gai_strerror mkostemp mkstemp getline getdelim sync \
difftime posix_memalign \
getpwent endpwent getgrent endgrent \
touchlock \
......@@ -3934,7 +3934,7 @@ case $opsys in
AC_DEFINE(PTY_TTY_NAME_SPRINTF, [{ char *ptyname = 0; sigset_t blocked; sigemptyset (&blocked); sigaddset (&blocked, SIGCHLD); pthread_sigmask (SIG_BLOCK, &blocked, 0); if (grantpt (fd) != -1 && unlockpt (fd) != -1) ptyname = ptsname(fd); pthread_sigmask (SIG_UNBLOCK, &blocked, 0); if (!ptyname) { close (fd); return -1; } snprintf (pty_name, sizeof pty_name, "%s", ptyname); }])
dnl if HAVE_POSIX_OPENPT
if test "x$ac_cv_func_posix_openpt" = xyes; then
AC_DEFINE(PTY_OPEN, [fd = posix_openpt (O_RDWR | O_NOCTTY)])
AC_DEFINE(PTY_OPEN, [fd = posix_openpt (O_RDWR | O_CLOEXEC | O_NOCTTY)])
AC_DEFINE(PTY_NAME_SPRINTF, [])
dnl if HAVE_GETPT
elif test "x$ac_cv_func_getpt" = xyes; then
......
/* Provide file descriptor control.
Copyright (C) 2009-2013 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>. */
#include <config.h>
/* Specification. */
#include <fcntl.h>
#include <errno.h>
#include <limits.h>
#include <stdarg.h>
#include <unistd.h>
#if !HAVE_FCNTL
# define rpl_fcntl fcntl
#endif
#undef fcntl
#if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
/* Get declarations of the native Windows API functions. */
# define WIN32_LEAN_AND_MEAN
# include <windows.h>
/* Get _get_osfhandle. */
# include "msvc-nothrow.h"
/* Upper bound on getdtablesize(). See lib/getdtablesize.c. */
# define OPEN_MAX_MAX 0x10000
/* Duplicate OLDFD into the first available slot of at least NEWFD,
which must be positive, with FLAGS determining whether the duplicate
will be inheritable. */
static int
dupfd (int oldfd, int newfd, int flags)
{
/* Mingw has no way to create an arbitrary fd. Iterate until all
file descriptors less than newfd are filled up. */
HANDLE curr_process = GetCurrentProcess ();
HANDLE old_handle = (HANDLE) _get_osfhandle (oldfd);
unsigned char fds_to_close[OPEN_MAX_MAX / CHAR_BIT];
unsigned int fds_to_close_bound = 0;
int result;
BOOL inherit = flags & O_CLOEXEC ? FALSE : TRUE;
int mode;
if (newfd < 0 || getdtablesize () <= newfd)
{
errno = EINVAL;
return -1;
}
if (old_handle == INVALID_HANDLE_VALUE
|| (mode = setmode (oldfd, O_BINARY)) == -1)
{
/* oldfd is not open, or is an unassigned standard file
descriptor. */
errno = EBADF;
return -1;
}
setmode (oldfd, mode);
flags |= mode;
for (;;)
{
HANDLE new_handle;
int duplicated_fd;
unsigned int index;
if (!DuplicateHandle (curr_process, /* SourceProcessHandle */
old_handle, /* SourceHandle */
curr_process, /* TargetProcessHandle */
(PHANDLE) &new_handle, /* TargetHandle */
(DWORD) 0, /* DesiredAccess */
inherit, /* InheritHandle */
DUPLICATE_SAME_ACCESS)) /* Options */
{
/* TODO: Translate GetLastError () into errno. */
errno = EMFILE;
result = -1;
break;
}
duplicated_fd = _open_osfhandle ((intptr_t) new_handle, flags);
if (duplicated_fd < 0)
{
CloseHandle (new_handle);
errno = EMFILE;
result = -1;
break;
}
if (newfd <= duplicated_fd)
{
result = duplicated_fd;
break;
}
/* Set the bit duplicated_fd in fds_to_close[]. */
index = (unsigned int) duplicated_fd / CHAR_BIT;
if (fds_to_close_bound <= index)
{
if (sizeof fds_to_close <= index)
/* Need to increase OPEN_MAX_MAX. */
abort ();
memset (fds_to_close + fds_to_close_bound, '\0',
index + 1 - fds_to_close_bound);
fds_to_close_bound = index + 1;
}
fds_to_close[index] |= 1 << ((unsigned int) duplicated_fd % CHAR_BIT);
}
/* Close the previous fds that turned out to be too small. */
{
int saved_errno = errno;
unsigned int duplicated_fd;
for (duplicated_fd = 0;
duplicated_fd < fds_to_close_bound * CHAR_BIT;
duplicated_fd++)
if ((fds_to_close[duplicated_fd / CHAR_BIT]
>> (duplicated_fd % CHAR_BIT))
& 1)
close (duplicated_fd);
errno = saved_errno;
}
# if REPLACE_FCHDIR
if (0 <= result)
result = _gl_register_dup (oldfd, result);
# endif
return result;
}
#endif /* W32 */
/* Perform the specified ACTION on the file descriptor FD, possibly
using the argument ARG further described below. This replacement
handles the following actions, and forwards all others on to the
native fcntl. An unrecognized ACTION returns -1 with errno set to
EINVAL.
F_DUPFD - duplicate FD, with int ARG being the minimum target fd.
If successful, return the duplicate, which will be inheritable;
otherwise return -1 and set errno.
F_DUPFD_CLOEXEC - duplicate FD, with int ARG being the minimum
target fd. If successful, return the duplicate, which will not be
inheritable; otherwise return -1 and set errno.
F_GETFD - ARG need not be present. If successful, return a
non-negative value containing the descriptor flags of FD (only
FD_CLOEXEC is portable, but other flags may be present); otherwise
return -1 and set errno. */
int
rpl_fcntl (int fd, int action, /* arg */...)
{
va_list arg;
int result = -1;
va_start (arg, action);
switch (action)
{
#if !HAVE_FCNTL
case F_DUPFD:
{
int target = va_arg (arg, int);
result = dupfd (fd, target, 0);
break;
}
#elif FCNTL_DUPFD_BUGGY || REPLACE_FCHDIR
case F_DUPFD:
{
int target = va_arg (arg, int);
/* Detect invalid target; needed for cygwin 1.5.x. */
if (target < 0 || getdtablesize () <= target)
errno = EINVAL;
else
{
/* Haiku alpha 2 loses fd flags on original. */
int flags = fcntl (fd, F_GETFD);
if (flags < 0)
{
result = -1;
break;
}
result = fcntl (fd, action, target);
if (0 <= result && fcntl (fd, F_SETFD, flags) == -1)
{
int saved_errno = errno;
close (result);
result = -1;
errno = saved_errno;
}
# if REPLACE_FCHDIR
if (0 <= result)
result = _gl_register_dup (fd, result);
# endif
}
break;
} /* F_DUPFD */
#endif /* FCNTL_DUPFD_BUGGY || REPLACE_FCHDIR */
case F_DUPFD_CLOEXEC:
{
int target = va_arg (arg, int);
#if !HAVE_FCNTL
result = dupfd (fd, target, O_CLOEXEC);
break;
#else /* HAVE_FCNTL */
/* Try the system call first, if the headers claim it exists
(that is, if GNULIB_defined_F_DUPFD_CLOEXEC is 0), since we
may be running with a glibc that has the macro but with an
older kernel that does not support it. Cache the
information on whether the system call really works, but
avoid caching failure if the corresponding F_DUPFD fails
for any reason. 0 = unknown, 1 = yes, -1 = no. */
static int have_dupfd_cloexec = GNULIB_defined_F_DUPFD_CLOEXEC ? -1 : 0;
if (0 <= have_dupfd_cloexec)
{
result = fcntl (fd, action, target);
if (0 <= result || errno != EINVAL)
{
have_dupfd_cloexec = 1;
# if REPLACE_FCHDIR
if (0 <= result)
result = _gl_register_dup (fd, result);
# endif
}
else
{
result = rpl_fcntl (fd, F_DUPFD, target);
if (result < 0)
break;
have_dupfd_cloexec = -1;
}
}
else
result = rpl_fcntl (fd, F_DUPFD, target);
if (0 <= result && have_dupfd_cloexec == -1)
{
int flags = fcntl (result, F_GETFD);
if (flags < 0 || fcntl (result, F_SETFD, flags | FD_CLOEXEC) == -1)
{
int saved_errno = errno;
close (result);
errno = saved_errno;
result = -1;
}
}
break;
#endif /* HAVE_FCNTL */
} /* F_DUPFD_CLOEXEC */
#if !HAVE_FCNTL
case F_GETFD:
{
# if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
HANDLE handle = (HANDLE) _get_osfhandle (fd);
DWORD flags;
if (handle == INVALID_HANDLE_VALUE
|| GetHandleInformation (handle, &flags) == 0)
errno = EBADF;
else
result = (flags & HANDLE_FLAG_INHERIT) ? 0 : FD_CLOEXEC;
# else /* !W32 */
/* Use dup2 to reject invalid file descriptors. No way to
access this information, so punt. */
if (0 <= dup2 (fd, fd))
result = 0;
# endif /* !W32 */
break;
} /* F_GETFD */
#endif /* !HAVE_FCNTL */
/* Implementing F_SETFD on mingw is not trivial - there is no
API for changing the O_NOINHERIT bit on an fd, and merely
changing the HANDLE_FLAG_INHERIT bit on the underlying handle
can lead to odd state. It may be possible by duplicating the
handle, using _open_osfhandle with the right flags, then
using dup2 to move the duplicate onto the original, but that
is not supported for now. */
default:
{
#if HAVE_FCNTL
void *p = va_arg (arg, void *);
result = fcntl (fd, action, p);
#else
errno = EINVAL;
#endif
break;
}
}
va_end (arg);
return result;
}
/* getdtablesize() function for platforms that don't have it.
Copyright (C) 2008-2013 Free Software Foundation, Inc.
Written by Bruno Haible <bruno@clisp.org>, 2008.
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 <config.h>
/* Specification. */
#include <unistd.h>
#if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
#include <stdio.h>
#include "msvc-inval.h"
#if HAVE_MSVC_INVALID_PARAMETER_HANDLER
static int
_setmaxstdio_nothrow (int newmax)
{
int result;
TRY_MSVC_INVAL
{
result = _setmaxstdio (newmax);
}
CATCH_MSVC_INVAL
{
result = -1;
}
DONE_MSVC_INVAL;
return result;
}
# define _setmaxstdio _setmaxstdio_nothrow
#endif
/* Cache for the previous getdtablesize () result. */
static int dtablesize;
int
getdtablesize (void)
{
if (dtablesize == 0)
{
/* We are looking for the number N such that the valid file descriptors
are 0..N-1. It can be obtained through a loop as follows:
{
int fd;
for (fd = 3; fd < 65536; fd++)
if (dup2 (0, fd) == -1)
break;
return fd;
}
On Windows XP, the result is 2048.
The drawback of this loop is that it allocates memory for a libc
internal array that is never freed.
The number N can also be obtained as the upper bound for
_getmaxstdio (). _getmaxstdio () returns the maximum number of open
FILE objects. The sanity check in _setmaxstdio reveals the maximum
number of file descriptors. This too allocates memory, but it is
freed when we call _setmaxstdio with the original value. */
int orig_max_stdio = _getmaxstdio ();
unsigned int bound;
for (bound = 0x10000; _setmaxstdio (bound) < 0; bound = bound / 2)
;
_setmaxstdio (orig_max_stdio);
dtablesize = bound;
}
return dtablesize;
}
#endif
......@@ -21,7 +21,7 @@
# the same distribution terms as the rest of that program.
#
# Generated by gnulib-tool.
# Reproduce by: gnulib-tool --import --dir=. --lib=libgnu --source-base=lib --m4-base=m4 --doc-base=doc --tests-base=tests --aux-dir=build-aux --avoid=dup --avoid=fchdir --avoid=fcntl --avoid=fstat --avoid=malloc-posix --avoid=msvc-inval --avoid=msvc-nothrow --avoid=open --avoid=openat-die --avoid=opendir --avoid=raise --avoid=save-cwd --avoid=select --avoid=sigprocmask --avoid=sys_types --avoid=threadlib --makefile-name=gnulib.mk --conditional-dependencies --no-libtool --macro-prefix=gl --no-vc-files alloca-opt c-ctype c-strcase careadlinkat close-stream crypto/md5 crypto/sha1 crypto/sha256 crypto/sha512 dtoastr dtotimespec dup2 environ execinfo faccessat fcntl-h fdatasync fdopendir filemode fstatat fsync getloadavg getopt-gnu gettime gettimeofday ignore-value intprops largefile lstat manywarnings memrchr mktime pselect pthread_sigmask putenv qacl readlink readlinkat sig2str socklen stat-time stdalign stdarg stdbool stdio strftime strtoimax strtoumax symlink sys_stat sys_time time timer-time timespec-add timespec-sub unsetenv utimens warnings
# Reproduce by: gnulib-tool --import --dir=. --lib=libgnu --source-base=lib --m4-base=m4 --doc-base=doc --tests-base=tests --aux-dir=build-aux --avoid=binary-io --avoid=close --avoid=dup --avoid=fchdir --avoid=fstat --avoid=malloc-posix --avoid=msvc-inval --avoid=msvc-nothrow --avoid=open --avoid=openat-die --avoid=opendir --avoid=raise --avoid=save-cwd --avoid=select --avoid=sigprocmask --avoid=sys_types --avoid=threadlib --makefile-name=gnulib.mk --conditional-dependencies --no-libtool --macro-prefix=gl --no-vc-files alloca-opt c-ctype c-strcase careadlinkat close-stream crypto/md5 crypto/sha1 crypto/sha256 crypto/sha512 dtoastr dtotimespec dup2 environ execinfo faccessat fcntl fcntl-h fdatasync fdopendir filemode fstatat fsync getloadavg getopt-gnu gettime gettimeofday ignore-value intprops largefile lstat manywarnings memrchr mktime pipe2 pselect pthread_sigmask putenv qacl readlink readlinkat sig2str socklen stat-time stdalign stdarg stdbool stdio strftime strtoimax strtoumax symlink sys_stat sys_time time timer-time timespec-add timespec-sub unsetenv utimens warnings
MOSTLYCLEANFILES += core *.stackdump
......@@ -296,6 +296,15 @@ EXTRA_libgnu_a_SOURCES += at-func.c faccessat.c
## end gnulib module faccessat
## begin gnulib module fcntl
EXTRA_DIST += fcntl.c
EXTRA_libgnu_a_SOURCES += fcntl.c
## end gnulib module fcntl
## begin gnulib module fcntl-h
BUILT_SOURCES += fcntl.h
......@@ -384,6 +393,17 @@ EXTRA_libgnu_a_SOURCES += fsync.c
## end gnulib module fsync
## begin gnulib module getdtablesize
if gl_GNULIB_ENABLED_getdtablesize
endif
EXTRA_DIST += getdtablesize.c
EXTRA_libgnu_a_SOURCES += getdtablesize.c
## end gnulib module getdtablesize
## begin gnulib module getgroups
if gl_GNULIB_ENABLED_getgroups
......@@ -568,6 +588,12 @@ EXTRA_DIST += pathmax.h
## end gnulib module pathmax
## begin gnulib module pipe2
libgnu_a_SOURCES += pipe2.c
## end gnulib module pipe2
## begin gnulib module pselect
......@@ -1704,9 +1730,7 @@ EXTRA_DIST += utimens.h
## begin gnulib module verify
if gl_GNULIB_ENABLED_verify
endif
EXTRA_DIST += verify.h
## end gnulib module verify
......
/* Create a pipe, with specific opening flags.
Copyright (C) 2009-2013 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, 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 <config.h>
/* Specification. */
#include <unistd.h>
#include <errno.h>
#include <fcntl.h>
#if GNULIB_BINARY_IO
# include "binary-io.h"
#endif
#include "verify.h"
#if GNULIB_defined_O_NONBLOCK
# include "nonblocking.h"
#endif
#if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
/* Native Windows API. */
# include <io.h>
#endif
int
pipe2 (int fd[2], int flags)
{
/* Mingw _pipe() corrupts fd on failure; also, if we succeed at
creating the pipe but later fail at changing fcntl, we want
to leave fd unchanged: http://austingroupbugs.net/view.php?id=467 */
int tmp[2];
tmp[0] = fd[0];
tmp[1] = fd[1];
#if HAVE_PIPE2
# undef pipe2
/* Try the system call first, if it exists. (We may be running with a glibc
that has the function but with an older kernel that lacks it.) */
{
/* Cache the information whether the system call really exists. */
static int have_pipe2_really; /* 0 = unknown, 1 = yes, -1 = no */
if (have_pipe2_really >= 0)
{
int result = pipe2 (fd, flags);
if (!(result < 0 && errno == ENOSYS))
{
have_pipe2_really = 1;
return result;
}
have_pipe2_really = -1;
}
}
#endif
/* Check the supported flags. */
if ((flags & ~(O_CLOEXEC | O_NONBLOCK | O_BINARY | O_TEXT)) != 0)
{
errno = EINVAL;
return -1;
}
#if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
/* Native Windows API. */
if (_pipe (fd, 4096, flags & ~O_NONBLOCK) < 0)
{
fd[0] = tmp[0];
fd[1] = tmp[1];
return -1;
}
/* O_NONBLOCK handling.
On native Windows platforms, O_NONBLOCK is defined by gnulib. Use the
functions defined by the gnulib module 'nonblocking'. */
# if GNULIB_defined_O_NONBLOCK
if (flags & O_NONBLOCK)
{
if (set_nonblocking_flag (fd[0], true) != 0
|| set_nonblocking_flag (fd[1], true) != 0)
goto fail;
}
# else
{
verify (O_NONBLOCK == 0);
}
# endif
return 0;