X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=m4%2Ffchdir.m4;h=30e0af1639e834297463b527ca5ffc1328cb8250;hb=39a489fa27ab3873e0fc0f65844413f46fcb2117;hp=fd170d294470c0ae919b02c7c27d092b2a946d4f;hpb=73f2a1c055c8dfa46d1a4db04a841d952e11c6a0;p=gnulib.git

diff --git a/m4/fchdir.m4 b/m4/fchdir.m4
index fd170d294..30e0af163 100644
--- a/m4/fchdir.m4
+++ b/m4/fchdir.m4
@@ -1,5 +1,5 @@
-# fchdir.m4 serial 4
-dnl Copyright (C) 2006-2007 Free Software Foundation, Inc.
+# fchdir.m4 serial 20
+dnl Copyright (C) 2006-2011 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.
@@ -7,19 +7,44 @@ dnl with or without modifications, as long as this notice is preserved.
 AC_DEFUN([gl_FUNC_FCHDIR],
 [
   AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
-  AC_CHECK_FUNCS_ONCE([fchdir])
-  if test $ac_cv_func_fchdir = no; then
-    REPLACE_FCHDIR=1
+  AC_REQUIRE([gl_DIRENT_H_DEFAULTS])
+
+  AC_CHECK_DECLS_ONCE([fchdir])
+  if test $ac_cv_have_decl_fchdir = no; then
+    HAVE_DECL_FCHDIR=0
+  fi
+
+  AC_REQUIRE([gl_TEST_FCHDIR])
+  if test $HAVE_FCHDIR = 0; then
     AC_LIBOBJ([fchdir])
     gl_PREREQ_FCHDIR
-    AC_DEFINE([FCHDIR_REPLACEMENT], 1,
-      [Define if gnulib's fchdir() replacement is used.])
-    gl_CHECK_NEXT_HEADERS([dirent.h])
-    DIRENT_H='dirent.h'
-  else
-    DIRENT_H=
+    AC_DEFINE([REPLACE_FCHDIR], [1],
+      [Define to 1 if gnulib's fchdir() replacement is used.])
+    dnl We must also replace anything that can manipulate a directory fd,
+    dnl to keep our bookkeeping up-to-date.  We don't have to replace
+    dnl fstatat, since no platform has fstatat but lacks fchdir.
+    AC_CACHE_CHECK([whether open can visit directories],
+      [gl_cv_func_open_directory_works],
+      [AC_RUN_IFELSE([AC_LANG_PROGRAM([[#include <fcntl.h>
+]], [return open(".", O_RDONLY) < 0;])],
+        [gl_cv_func_open_directory_works=yes],
+        [gl_cv_func_open_directory_works=no],
+        [gl_cv_func_open_directory_works="guessing no"])])
+    if test "$gl_cv_func_open_directory_works" != yes; then
+      AC_DEFINE([REPLACE_OPEN_DIRECTORY], [1], [Define to 1 if open() should
+work around the inability to open a directory.])
+    fi
+  fi
+])
+
+# Determine whether to use the overrides in lib/fchdir.c.
+AC_DEFUN([gl_TEST_FCHDIR],
+[
+  AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
+  AC_CHECK_FUNCS_ONCE([fchdir])
+  if test $ac_cv_func_fchdir = no; then
+    HAVE_FCHDIR=0
   fi
-  AC_SUBST([DIRENT_H])
 ])
 
 # Prerequisites of lib/fchdir.c.