X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=m4%2Fopenat.m4;h=313dc6f7f5ce5229ecd2ce6b0d878fce4fabb909;hb=e062ed7a99ca4e88a93db19362800a3326a462ea;hp=e7286487e4c2e576bdcf8cb1c9ab780149488232;hpb=bc9a52afd88b484ff686a9ce18ec38fba6e2e4a9;p=gnulib.git

diff --git a/m4/openat.m4 b/m4/openat.m4
index e7286487e..313dc6f7f 100644
--- a/m4/openat.m4
+++ b/m4/openat.m4
@@ -1,7 +1,7 @@
-#serial 12
+#serial 15
 # See if we need to use our replacement for Solaris' openat et al functions.
 
-dnl Copyright (C) 2004, 2005, 2006 Free Software Foundation, Inc.
+dnl Copyright (C) 2004, 2005, 2006, 2007 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.
@@ -24,9 +24,70 @@ AC_DEFUN([gl_FUNC_OPENAT],
       [Define to rpl_ if the openat replacement function should be used.])
     gl_PREREQ_OPENAT;;
   esac
+  gl_FUNC_FCHOWNAT
+])
+
+# gl_FUNC_FCHOWNAT_DEREF_BUG([ACTION-IF-BUGGY[, ACTION-IF-NOT_BUGGY]])
+AC_DEFUN([gl_FUNC_FCHOWNAT_DEREF_BUG],
+[
+  AC_CACHE_CHECK([whether fchownat works with AT_SYMLINK_NOFOLLOW],
+    gl_cv_func_fchownat_nofollow_works,
+    [
+     gl_dangle=conftest.dangle
+     # Remove any remnants of a previous test.
+     rm -f $gl_dangle
+     # Arrange for deletion of the temporary file this test creates.
+     ac_clean_files="$ac_clean_files $gl_dangle"
+     AC_RUN_IFELSE(
+       [AC_LANG_SOURCE(
+	  [[
+#include <fcntl.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <sys/types.h>
+int
+main ()
+{
+  return (fchownat (AT_FDCWD, "$gl_dangle", -1, getgid (),
+		    AT_SYMLINK_NOFOLLOW) != 0
+	  && errno == ENOENT);
+}
+          ]])],
+    [gl_cv_func_fchownat_nofollow_works=yes],
+    [gl_cv_func_fchownat_nofollow_works=no],
+    [gl_cv_func_fchownat_nofollow_works=no],
+    )
+  ])
+  AS_IF([test $gl_cv_func_fchownat_nofollow_works = no], [$1], [$2])
+])
+
+# If we have the fchownat function, and it has the bug (in glibc-2.4)
+# that it dereferences symlinks even with AT_SYMLINK_NOFOLLOW, then
+# use the replacement function.
+# Also use the replacement function if fchownat is simply not available.
+AC_DEFUN([gl_FUNC_FCHOWNAT],
+[
+  # Assume we'll use the replacement function.
+  # The only case in which we won't is when we have fchownat, and it works.
+  use_replacement_fchownat=yes
+
+  AC_CHECK_FUNC([fchownat], [have_fchownat=yes], [have_fchownat=no])
+  if test $have_fchownat = yes; then
+    gl_FUNC_FCHOWNAT_DEREF_BUG([have_fchownat_bug=yes])
+    if test $have_fchownat_bug = no; then
+      use_replacement_fchownat=no
+    fi
+  fi
+
+  if test $use_replacement_fchownat = yes; then
+    AC_LIBOBJ(fchownat)
+    AC_DEFINE(fchownat, rpl_fchownat,
+      [Define to rpl_fchownat if the replacement function should be used.])
+  fi
 ])
 
 AC_DEFUN([gl_PREREQ_OPENAT],
 [
-  AC_REQUIRE([gl_SAVE_CWD])
+  :
 ])