1#serial 15
2# See if we need to use our replacement for Solaris' openat et al functions.
3
4dnl Copyright (C) 2004, 2005, 2006, 2007 Free Software Foundation, Inc.
5dnl This file is free software; the Free Software Foundation
6dnl gives unlimited permission to copy and/or distribute it,
7dnl with or without modifications, as long as this notice is preserved.
8
9# Written by Jim Meyering.
10
11AC_DEFUN([gl_FUNC_OPENAT],
12[
13  AC_LIBOBJ([openat-proc])
14  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
15  AC_CHECK_FUNCS_ONCE([lchmod])
16  AC_CHECK_FUNCS_ONCE([fdopendir])
17  AC_REPLACE_FUNCS([fchmodat mkdirat openat])
18  case $ac_cv_func_openat+$ac_cv_func_lstat_dereferences_slashed_symlink in
19  yes+yes) ;;
20  yes+*) AC_LIBOBJ([fstatat]);;
21  *)
22    AC_DEFINE([__OPENAT_PREFIX], [[rpl_]],
23      [Define to rpl_ if the openat replacement function should be used.])
24    gl_PREREQ_OPENAT;;
25  esac
26  gl_FUNC_FCHOWNAT
27])
28
29# gl_FUNC_FCHOWNAT_DEREF_BUG([ACTION-IF-BUGGY[, ACTION-IF-NOT_BUGGY]])
30AC_DEFUN([gl_FUNC_FCHOWNAT_DEREF_BUG],
31[
32  AC_CACHE_CHECK([whether fchownat works with AT_SYMLINK_NOFOLLOW],
33    gl_cv_func_fchownat_nofollow_works,
34    [
35     gl_dangle=conftest.dangle
36     # Remove any remnants of a previous test.
37     rm -f $gl_dangle
38     # Arrange for deletion of the temporary file this test creates.
39     ac_clean_files="$ac_clean_files $gl_dangle"
40     ln -s conftest.no-such $gl_dangle
41     AC_RUN_IFELSE(
42       [AC_LANG_SOURCE(
43	  [[
44#include <fcntl.h>
45#include <unistd.h>
46#include <stdlib.h>
47#include <errno.h>
48#include <sys/types.h>
49int
50main ()
51{
52  return (fchownat (AT_FDCWD, "$gl_dangle", -1, getgid (),
53		    AT_SYMLINK_NOFOLLOW) != 0
54	  && errno == ENOENT);
55}
56          ]])],
57    [gl_cv_func_fchownat_nofollow_works=yes],
58    [gl_cv_func_fchownat_nofollow_works=no],
59    [gl_cv_func_fchownat_nofollow_works=no],
60    )
61  ])
62  AS_IF([test $gl_cv_func_fchownat_nofollow_works = no], [$1], [$2])
63])
64
65# If we have the fchownat function, and it has the bug (in glibc-2.4)
66# that it dereferences symlinks even with AT_SYMLINK_NOFOLLOW, then
67# use the replacement function.
68# Also use the replacement function if fchownat is simply not available.
69AC_DEFUN([gl_FUNC_FCHOWNAT],
70[
71  # Assume we'll use the replacement function.
72  # The only case in which we won't is when we have fchownat, and it works.
73  use_replacement_fchownat=yes
74
75  AC_CHECK_FUNC([fchownat], [have_fchownat=yes], [have_fchownat=no])
76  if test $have_fchownat = yes; then
77    gl_FUNC_FCHOWNAT_DEREF_BUG([], [use_replacement_fchownat=no])
78  fi
79
80  if test $use_replacement_fchownat = yes; then
81    AC_LIBOBJ(fchownat)
82    AC_DEFINE(fchownat, rpl_fchownat,
83      [Define to rpl_fchownat if the replacement function should be used.])
84  fi
85])
86
87AC_DEFUN([gl_PREREQ_OPENAT],
88[
89  :
90])
91