105 lines
3.7 KiB
Text
105 lines
3.7 KiB
Text
#serial 27
|
|
dnl Copyright (C) 2002, 2005, 2007, 2009-2023 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_DUP2],
|
|
[
|
|
AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
|
|
AC_REQUIRE([AC_CANONICAL_HOST])
|
|
AC_CACHE_CHECK([whether dup2 works], [gl_cv_func_dup2_works],
|
|
[AC_RUN_IFELSE([
|
|
AC_LANG_PROGRAM(
|
|
[[#include <errno.h>
|
|
#include <fcntl.h>
|
|
#include <limits.h>
|
|
#include <sys/resource.h>
|
|
#include <unistd.h>
|
|
]GL_MDA_DEFINES[
|
|
#ifndef RLIM_SAVED_CUR
|
|
# define RLIM_SAVED_CUR RLIM_INFINITY
|
|
#endif
|
|
#ifndef RLIM_SAVED_MAX
|
|
# define RLIM_SAVED_MAX RLIM_INFINITY
|
|
#endif
|
|
]],
|
|
[[int result = 0;
|
|
int bad_fd = INT_MAX;
|
|
struct rlimit rlim;
|
|
if (getrlimit (RLIMIT_NOFILE, &rlim) == 0
|
|
&& 0 <= rlim.rlim_cur && rlim.rlim_cur <= INT_MAX
|
|
&& rlim.rlim_cur != RLIM_INFINITY
|
|
&& rlim.rlim_cur != RLIM_SAVED_MAX
|
|
&& rlim.rlim_cur != RLIM_SAVED_CUR)
|
|
bad_fd = rlim.rlim_cur;
|
|
#ifdef FD_CLOEXEC
|
|
if (fcntl (1, F_SETFD, FD_CLOEXEC) == -1)
|
|
result |= 1;
|
|
#endif
|
|
if (dup2 (1, 1) != 1)
|
|
result |= 2;
|
|
#ifdef FD_CLOEXEC
|
|
if (fcntl (1, F_GETFD) != FD_CLOEXEC)
|
|
result |= 4;
|
|
#endif
|
|
close (0);
|
|
if (dup2 (0, 0) != -1)
|
|
result |= 8;
|
|
/* Many gnulib modules require POSIX conformance of EBADF. */
|
|
if (dup2 (2, bad_fd) == -1 && errno != EBADF)
|
|
result |= 16;
|
|
/* Flush out some cygwin core dumps. */
|
|
if (dup2 (2, -1) != -1 || errno != EBADF)
|
|
result |= 32;
|
|
dup2 (2, 255);
|
|
dup2 (2, 256);
|
|
/* On OS/2 kLIBC, dup2() does not work on a directory fd. */
|
|
{
|
|
int fd = open (".", O_RDONLY);
|
|
if (fd == -1)
|
|
result |= 64;
|
|
else if (dup2 (fd, fd + 1) == -1)
|
|
result |= 128;
|
|
close (fd);
|
|
}
|
|
return result;]])
|
|
],
|
|
[gl_cv_func_dup2_works=yes], [gl_cv_func_dup2_works=no],
|
|
[case "$host_os" in
|
|
mingw*) # on this platform, dup2 always returns 0 for success
|
|
gl_cv_func_dup2_works="guessing no" ;;
|
|
cygwin*) # on cygwin 1.5.x, dup2(1,1) returns 0
|
|
gl_cv_func_dup2_works="guessing no" ;;
|
|
aix* | freebsd*)
|
|
# on AIX 7.1 and FreeBSD 6.1, dup2 (1,toobig) gives EMFILE,
|
|
# not EBADF.
|
|
gl_cv_func_dup2_works="guessing no" ;;
|
|
haiku*) # on Haiku alpha 2, dup2(1, 1) resets FD_CLOEXEC.
|
|
gl_cv_func_dup2_works="guessing no" ;;
|
|
*-android*) # implemented using dup3(), which fails if oldfd == newfd
|
|
gl_cv_func_dup2_works="guessing no" ;;
|
|
os2*) # on OS/2 kLIBC, dup2() does not work on a directory fd.
|
|
gl_cv_func_dup2_works="guessing no" ;;
|
|
*) gl_cv_func_dup2_works="guessing yes" ;;
|
|
esac])
|
|
])
|
|
case "$gl_cv_func_dup2_works" in
|
|
*yes) ;;
|
|
*)
|
|
REPLACE_DUP2=1
|
|
AC_CHECK_FUNCS([setdtablesize])
|
|
;;
|
|
esac
|
|
dnl Replace dup2() for supporting the gnulib-defined fchdir() function,
|
|
dnl to keep fchdir's bookkeeping up-to-date.
|
|
m4_ifdef([gl_FUNC_FCHDIR], [
|
|
gl_TEST_FCHDIR
|
|
if test $HAVE_FCHDIR = 0; then
|
|
REPLACE_DUP2=1
|
|
fi
|
|
])
|
|
])
|
|
|
|
# Prerequisites of lib/dup2.c.
|
|
AC_DEFUN([gl_PREREQ_DUP2], [])
|