| 1 | # fchdir.m4 serial 26
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| 2 | dnl Copyright (C) 2006-2021 Free Software Foundation, Inc.
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| 3 | dnl This file is free software; the Free Software Foundation
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| 4 | dnl gives unlimited permission to copy and/or distribute it,
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| 5 | dnl with or without modifications, as long as this notice is preserved.
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| 6 |
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| 7 | AC_DEFUN([gl_FUNC_FCHDIR],
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| 8 | [
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| 9 | AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
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| 10 | AC_REQUIRE([gl_DIRENT_H_DEFAULTS])
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| 11 | AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
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| 12 |
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| 13 | AC_CHECK_DECLS_ONCE([fchdir])
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| 14 | if test $ac_cv_have_decl_fchdir = no; then
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| 15 | HAVE_DECL_FCHDIR=0
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| 16 | fi
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| 17 |
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| 18 | AC_REQUIRE([gl_TEST_FCHDIR])
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| 19 | if test $HAVE_FCHDIR = 0; then
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| 20 | AC_LIBOBJ([fchdir])
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| 21 | gl_PREREQ_FCHDIR
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| 22 | AC_DEFINE([REPLACE_FCHDIR], [1],
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| 23 | [Define to 1 if gnulib's fchdir() replacement is used.])
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| 24 | dnl We must also replace anything that can manipulate a directory fd,
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| 25 | dnl to keep our bookkeeping up-to-date. We don't have to replace
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| 26 | dnl fstatat, since no platform has fstatat but lacks fchdir.
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| 27 | AC_CACHE_CHECK([whether open can visit directories],
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| 28 | [gl_cv_func_open_directory_works],
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| 29 | [AC_RUN_IFELSE(
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| 30 | [AC_LANG_PROGRAM(
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| 31 | [[#include <fcntl.h>
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| 32 | ]GL_MDA_DEFINES],
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| 33 | [[return open(".", O_RDONLY) < 0;]])],
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| 34 | [gl_cv_func_open_directory_works=yes],
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| 35 | [gl_cv_func_open_directory_works=no],
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| 36 | [case "$host_os" in
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| 37 | # Guess yes on Linux systems.
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| 38 | linux-* | linux) gl_cv_func_open_directory_works="guessing yes" ;;
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| 39 | # Guess yes on glibc systems.
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| 40 | *-gnu* | gnu*) gl_cv_func_open_directory_works="guessing yes" ;;
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| 41 | # Guess no on native Windows.
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| 42 | mingw*) gl_cv_func_open_directory_works="guessing no" ;;
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| 43 | # If we don't know, obey --enable-cross-guesses.
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| 44 | *) gl_cv_func_open_directory_works="$gl_cross_guess_normal" ;;
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| 45 | esac
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| 46 | ])])
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| 47 | case "$gl_cv_func_open_directory_works" in
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| 48 | *yes) ;;
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| 49 | *)
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| 50 | AC_DEFINE([REPLACE_OPEN_DIRECTORY], [1], [Define to 1 if open() should
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| 51 | work around the inability to open a directory.])
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| 52 | ;;
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| 53 | esac
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| 54 | fi
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| 55 | ])
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| 56 |
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| 57 | # Determine whether to use the overrides in lib/fchdir.c.
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| 58 | AC_DEFUN([gl_TEST_FCHDIR],
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| 59 | [
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| 60 | AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
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| 61 | AC_CHECK_FUNCS_ONCE([fchdir])
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| 62 | if test $ac_cv_func_fchdir = no; then
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| 63 | HAVE_FCHDIR=0
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| 64 | fi
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| 65 | ])
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| 66 |
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| 67 | # Prerequisites of lib/fchdir.c.
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| 68 | AC_DEFUN([gl_PREREQ_FCHDIR], [:])
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