| 1 | #serial 27
|
|---|
| 2 | dnl Copyright (C) 2002, 2005, 2007, 2009-2021 Free Software Foundation, Inc.
|
|---|
| 3 | dnl This file is free software; the Free Software Foundation
|
|---|
| 4 | dnl gives unlimited permission to copy and/or distribute it,
|
|---|
| 5 | dnl with or without modifications, as long as this notice is preserved.
|
|---|
| 6 |
|
|---|
| 7 | AC_DEFUN([gl_FUNC_DUP2],
|
|---|
| 8 | [
|
|---|
| 9 | AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
|
|---|
| 10 | AC_REQUIRE([AC_CANONICAL_HOST])
|
|---|
| 11 | AC_CACHE_CHECK([whether dup2 works], [gl_cv_func_dup2_works],
|
|---|
| 12 | [AC_RUN_IFELSE([
|
|---|
| 13 | AC_LANG_PROGRAM(
|
|---|
| 14 | [[#include <errno.h>
|
|---|
| 15 | #include <fcntl.h>
|
|---|
| 16 | #include <limits.h>
|
|---|
| 17 | #include <sys/resource.h>
|
|---|
| 18 | #include <unistd.h>
|
|---|
| 19 | ]GL_MDA_DEFINES[
|
|---|
| 20 | #ifndef RLIM_SAVED_CUR
|
|---|
| 21 | # define RLIM_SAVED_CUR RLIM_INFINITY
|
|---|
| 22 | #endif
|
|---|
| 23 | #ifndef RLIM_SAVED_MAX
|
|---|
| 24 | # define RLIM_SAVED_MAX RLIM_INFINITY
|
|---|
| 25 | #endif
|
|---|
| 26 | ]],
|
|---|
| 27 | [[int result = 0;
|
|---|
| 28 | int bad_fd = INT_MAX;
|
|---|
| 29 | struct rlimit rlim;
|
|---|
| 30 | if (getrlimit (RLIMIT_NOFILE, &rlim) == 0
|
|---|
| 31 | && 0 <= rlim.rlim_cur && rlim.rlim_cur <= INT_MAX
|
|---|
| 32 | && rlim.rlim_cur != RLIM_INFINITY
|
|---|
| 33 | && rlim.rlim_cur != RLIM_SAVED_MAX
|
|---|
| 34 | && rlim.rlim_cur != RLIM_SAVED_CUR)
|
|---|
| 35 | bad_fd = rlim.rlim_cur;
|
|---|
| 36 | #ifdef FD_CLOEXEC
|
|---|
| 37 | if (fcntl (1, F_SETFD, FD_CLOEXEC) == -1)
|
|---|
| 38 | result |= 1;
|
|---|
| 39 | #endif
|
|---|
| 40 | if (dup2 (1, 1) != 1)
|
|---|
| 41 | result |= 2;
|
|---|
| 42 | #ifdef FD_CLOEXEC
|
|---|
| 43 | if (fcntl (1, F_GETFD) != FD_CLOEXEC)
|
|---|
| 44 | result |= 4;
|
|---|
| 45 | #endif
|
|---|
| 46 | close (0);
|
|---|
| 47 | if (dup2 (0, 0) != -1)
|
|---|
| 48 | result |= 8;
|
|---|
| 49 | /* Many gnulib modules require POSIX conformance of EBADF. */
|
|---|
| 50 | if (dup2 (2, bad_fd) == -1 && errno != EBADF)
|
|---|
| 51 | result |= 16;
|
|---|
| 52 | /* Flush out some cygwin core dumps. */
|
|---|
| 53 | if (dup2 (2, -1) != -1 || errno != EBADF)
|
|---|
| 54 | result |= 32;
|
|---|
| 55 | dup2 (2, 255);
|
|---|
| 56 | dup2 (2, 256);
|
|---|
| 57 | /* On OS/2 kLIBC, dup2() does not work on a directory fd. */
|
|---|
| 58 | {
|
|---|
| 59 | int fd = open (".", O_RDONLY);
|
|---|
| 60 | if (fd == -1)
|
|---|
| 61 | result |= 64;
|
|---|
| 62 | else if (dup2 (fd, fd + 1) == -1)
|
|---|
| 63 | result |= 128;
|
|---|
| 64 | close (fd);
|
|---|
| 65 | }
|
|---|
| 66 | return result;]])
|
|---|
| 67 | ],
|
|---|
| 68 | [gl_cv_func_dup2_works=yes], [gl_cv_func_dup2_works=no],
|
|---|
| 69 | [case "$host_os" in
|
|---|
| 70 | mingw*) # on this platform, dup2 always returns 0 for success
|
|---|
| 71 | gl_cv_func_dup2_works="guessing no" ;;
|
|---|
| 72 | cygwin*) # on cygwin 1.5.x, dup2(1,1) returns 0
|
|---|
| 73 | gl_cv_func_dup2_works="guessing no" ;;
|
|---|
| 74 | aix* | freebsd*)
|
|---|
| 75 | # on AIX 7.1 and FreeBSD 6.1, dup2 (1,toobig) gives EMFILE,
|
|---|
| 76 | # not EBADF.
|
|---|
| 77 | gl_cv_func_dup2_works="guessing no" ;;
|
|---|
| 78 | haiku*) # on Haiku alpha 2, dup2(1, 1) resets FD_CLOEXEC.
|
|---|
| 79 | gl_cv_func_dup2_works="guessing no" ;;
|
|---|
| 80 | *-android*) # implemented using dup3(), which fails if oldfd == newfd
|
|---|
| 81 | gl_cv_func_dup2_works="guessing no" ;;
|
|---|
| 82 | os2*) # on OS/2 kLIBC, dup2() does not work on a directory fd.
|
|---|
| 83 | gl_cv_func_dup2_works="guessing no" ;;
|
|---|
| 84 | *) gl_cv_func_dup2_works="guessing yes" ;;
|
|---|
| 85 | esac])
|
|---|
| 86 | ])
|
|---|
| 87 | case "$gl_cv_func_dup2_works" in
|
|---|
| 88 | *yes) ;;
|
|---|
| 89 | *)
|
|---|
| 90 | REPLACE_DUP2=1
|
|---|
| 91 | AC_CHECK_FUNCS([setdtablesize])
|
|---|
| 92 | ;;
|
|---|
| 93 | esac
|
|---|
| 94 | dnl Replace dup2() for supporting the gnulib-defined fchdir() function,
|
|---|
| 95 | dnl to keep fchdir's bookkeeping up-to-date.
|
|---|
| 96 | m4_ifdef([gl_FUNC_FCHDIR], [
|
|---|
| 97 | gl_TEST_FCHDIR
|
|---|
| 98 | if test $HAVE_FCHDIR = 0; then
|
|---|
| 99 | REPLACE_DUP2=1
|
|---|
| 100 | fi
|
|---|
| 101 | ])
|
|---|
| 102 | ])
|
|---|
| 103 |
|
|---|
| 104 | # Prerequisites of lib/dup2.c.
|
|---|
| 105 | AC_DEFUN([gl_PREREQ_DUP2], [])
|
|---|
