This implements the 'dup3' replacement function.
Paolo's issue of use of older Linux kernels is not yet handled.
2009-08-23 Bruno Haible <br...@clisp.org>
New module 'dup3'.
* lib/unistd.in.h (dup3): New declaration.
* lib/dup3.c: New file.
* m4/dup3.m4: New file.
* m4/unistd_h.m4 (gl_UNISTD_H_DEFAULTS): Initialize GNULIB_DUP3 and
HAVE_DUP3.
* modules/unistd (Makefile.am): Substitute GNULIB_DUP3 and HAVE_DUP3.
* modules/dup3: New file.
* doc/glibc-functions/dup3.texi: Mention the new module.
================================= lib/dup3.c =================================
/* Copy a file descriptor, applying specific flags.
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 2, 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, write to the Free Software Foundation,
Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
#include <config.h>
/* Specification. */
#include <unistd.h>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include "binary-io.h"
#if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
/* Native Woe32 API. */
/* Get declarations of the Win32 API functions. */
# define WIN32_LEAN_AND_MEAN
# include <windows.h>
/* Upper bound on getdtablesize(). See lib/getdtablesize.c. */
# define OPEN_MAX_MAX 0x10000
#else
/* Unix API. */
# ifndef O_CLOEXEC
# define O_CLOEXEC 0
# endif
#endif
int
dup3 (int oldfd, int newfd, int flags)
{
if (oldfd < 0 || newfd < 0 || newfd >= getdtablesize ())
{
errno = EBADF;
return -1;
}
if (newfd == oldfd)
{
errno = EINVAL;
return -1;
}
/* Check the supported flags.
Note that O_NONBLOCK is not supported, because setting it on newfd
would implicitly also set it on oldfd. */
if ((flags & ~(O_CLOEXEC | O_BINARY | O_TEXT)) != 0)
{
errno = EINVAL;
return -1;
}
#if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
/* Native Woe32 API. */
if (flags & O_CLOEXEC)
{
/* Neither dup() nor dup2() can create a file descriptor with
O_CLOEXEC = O_NOINHERIT set. We need to use the low-level function
_open_osfhandle for this. 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;
if (old_handle == INVALID_HANDLE_VALUE)
{
/* oldfd is not open, or is an unassigned standard file
descriptor. */
errno = EBADF;
return -1;
}
close (newfd);
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 */
FALSE, /* InheritHandle */
DUPLICATE_SAME_ACCESS)) /* Options */
{
errno = EBADF; /* arbitrary */
result = -1;
break;
}
duplicated_fd = _open_osfhandle ((long) new_handle, flags);
if (duplicated_fd < 0)
{
CloseHandle (new_handle);
result = -1;
break;
}
if (duplicated_fd > newfd)
/* Shouldn't happen, since newfd is still closed. */
abort ();
if (duplicated_fd == newfd)
{
result = newfd;
break;
}
/* Set the bit duplicated_fd in fds_to_close[]. */
index = (unsigned int) duplicated_fd / CHAR_BIT;
if (index >= fds_to_close_bound)
{
if (index >= sizeof (fds_to_close))
/* 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;
}
return result;
}
if (dup2 (oldfd, newfd) < 0)
return -1;
#else
/* Unix API. */
if (dup2 (oldfd, newfd) < 0)
return -1;
/* POSIX <http://www.opengroup.org/onlinepubs/9699919799/functions/dup.html>
says that initially, the FD_CLOEXEC flag is cleared on newfd. */
if (flags & O_CLOEXEC)
{
int fcntl_flags;
if ((fcntl_flags = fcntl (newfd, F_GETFD, 0)) < 0
|| fcntl (newfd, F_SETFD, fcntl_flags | FD_CLOEXEC) == -1)
{
int saved_errno = errno;
close (newfd);
errno = saved_errno;
return -1;
}
}
#endif
#if O_BINARY
if (flags & O_BINARY)
setmode (newfd, O_BINARY);
else if (flags & O_TEXT)
setmode (newfd, O_TEXT);
#endif
return newfd;
}
================================= m4/dup3.m4 =================================
# dup3.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_DUP3],
[
AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
dnl Persuade glibc <unistd.h> to declare dup3().
AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
AC_CHECK_FUNCS_ONCE([dup3])
if test $ac_cv_func_dup3 != yes; then
HAVE_DUP3=0
AC_LIBOBJ([dup3])
fi
])
================================ modules/dup3 ================================
Description:
dup3() function: copy a file descriptor, applying specific flags.
Files:
lib/dup3.c
m4/dup3.m4
Depends-on:
unistd
fcntl
binary-io
getdtablesize
configure.ac:
gl_FUNC_DUP3
gl_UNISTD_MODULE_INDICATOR([dup3])
Makefile.am:
Include:
<unistd.h>
License:
LGPL
Maintainer:
Bruno Haible, Jim Meyering
==============================================================================
--- doc/glibc-functions/dup3.texi.orig 2009-08-24 00:11:26.000000000 +0200
+++ doc/glibc-functions/dup3.texi 2009-08-23 21:55:58.000000000 +0200
@@ -2,15 +2,15 @@
@subsection @code{dup3}
@findex dup3
-Gnulib module: ---
+Gnulib module: dup3
Portability problems fixed by Gnulib:
@itemize
+...@item
+This function is missing on all non-glibc platforms:
+MacOS X 10.3, FreeBSD 6.0, NetBSD 3.0, OpenBSD 3.8, AIX 5.1, HP-UX 11, IRIX
6.5, OSF/1 5.1, Solaris 10, Cygwin, mingw, Interix 3.5, BeOS.
@end itemize
Portability problems not fixed by Gnulib:
@itemize
-...@item
-This function is missing on all non-glibc platforms:
-MacOS X 10.3, FreeBSD 6.0, NetBSD 3.0, OpenBSD 3.8, AIX 5.1, HP-UX 11, IRIX
6.5, OSF/1 5.1, Solaris 10, Cygwin, mingw, Interix 3.5, BeOS.
@end itemize
--- lib/unistd.in.h.orig 2009-08-24 00:11:26.000000000 +0200
+++ lib/unistd.in.h 2009-08-24 00:11:22.000000000 +0200
@@ -178,6 +178,27 @@
#endif
+#if @GNULIB_DUP3@
+# if !...@have_dup3@
+/* Copy the file descriptor OLDFD into file descriptor NEWFD, with the
+ specified flags.
+ The flags are a bitmask, possibly including O_CLOEXEC (defined in <fcntl.h>)
+ and O_TEXT, O_BINARY (defined in "binary-io.h").
+ Close NEWFD first if it is open.
+ Return newfd if successful, otherwise -1 and errno set.
+ See the Linux man page at
+ <http://www.kernel.org/doc/man-pages/online/pages/man2/dup3.2.html>. */
+extern int dup3 (int oldfd, int newfd, int flags);
+# endif
+#elif defined GNULIB_POSIXCHECK
+# undef dup3
+# define dup3(o,n,f) \
+ (GL_LINK_WARNING ("dup3 is unportable - " \
+ "use gnulib module dup3 for portability"), \
+ dup3 (o, n, f))
+#endif
+
+
#if @GNULIB_ENVIRON@
# if !...@have_decl_environ@
/* Set of environment variables and values. An array of strings of the form
--- m4/unistd_h.m4.orig 2009-08-24 00:11:26.000000000 +0200
+++ m4/unistd_h.m4 2009-08-23 21:55:58.000000000 +0200
@@ -1,4 +1,4 @@
-# unistd_h.m4 serial 20
+# unistd_h.m4 serial 21
dnl Copyright (C) 2006-2009 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
@@ -35,6 +35,7 @@
GNULIB_CHOWN=0; AC_SUBST([GNULIB_CHOWN])
GNULIB_CLOSE=0; AC_SUBST([GNULIB_CLOSE])
GNULIB_DUP2=0; AC_SUBST([GNULIB_DUP2])
+ GNULIB_DUP3=0; AC_SUBST([GNULIB_DUP3])
GNULIB_ENVIRON=0; AC_SUBST([GNULIB_ENVIRON])
GNULIB_EUIDACCESS=0; AC_SUBST([GNULIB_EUIDACCESS])
GNULIB_FCHDIR=0; AC_SUBST([GNULIB_FCHDIR])
@@ -58,6 +59,7 @@
GNULIB_WRITE=0; AC_SUBST([GNULIB_WRITE])
dnl Assume proper GNU behavior unless another module says otherwise.
HAVE_DUP2=1; AC_SUBST([HAVE_DUP2])
+ HAVE_DUP3=1; AC_SUBST([HAVE_DUP3])
HAVE_EUIDACCESS=1; AC_SUBST([HAVE_EUIDACCESS])
HAVE_FSYNC=1; AC_SUBST([HAVE_FSYNC])
HAVE_FTRUNCATE=1; AC_SUBST([HAVE_FTRUNCATE])
--- modules/unistd.orig 2009-08-24 00:11:26.000000000 +0200
+++ modules/unistd 2009-08-23 21:55:58.000000000 +0200
@@ -28,6 +28,7 @@
-e 's|@''GNULIB_CHOWN''@|$(GNULIB_CHOWN)|g' \
-e 's|@''GNULIB_CLOSE''@|$(GNULIB_CLOSE)|g' \
-e 's|@''GNULIB_DUP2''@|$(GNULIB_DUP2)|g' \
+ -e 's|@''GNULIB_DUP3''@|$(GNULIB_DUP3)|g' \
-e 's|@''GNULIB_ENVIRON''@|$(GNULIB_ENVIRON)|g' \
-e 's|@''GNULIB_EUIDACCESS''@|$(GNULIB_EUIDACCESS)|g' \
-e 's|@''GNULIB_FCHDIR''@|$(GNULIB_FCHDIR)|g' \
@@ -50,6 +51,7 @@
-e 's|@''GNULIB_UNISTD_H_SIGPIPE''@|$(GNULIB_UNISTD_H_SIGPIPE)|g'
\
-e 's|@''GNULIB_WRITE''@|$(GNULIB_WRITE)|g' \
-e 's|@''HAVE_DUP2''@|$(HAVE_DUP2)|g' \
+ -e 's|@''HAVE_DUP3''@|$(HAVE_DUP3)|g' \
-e 's|@''HAVE_EUIDACCESS''@|$(HAVE_EUIDACCESS)|g' \
-e 's|@''HAVE_FSYNC''@|$(HAVE_FSYNC)|g' \
-e 's|@''HAVE_FTRUNCATE''@|$(HAVE_FTRUNCATE)|g' \
