X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=m4%2Fopenat.m4;h=80df704240d85021a5c0bc22e29630bcefaed84c;hb=df8bc51660941d7464dcd31170690519cb95c0c2;hp=27b0e59e6eb04dc50cb3281cab998ad5d62dba78;hpb=d9203c96c70e64ae24a2f2d36e1ba80d79628dc5;p=gnulib.git

diff --git a/m4/openat.m4 b/m4/openat.m4
index 27b0e59e6..80df70424 100644
--- a/m4/openat.m4
+++ b/m4/openat.m4
@@ -1,7 +1,7 @@
-#serial 3
-# See if we need to use our replacement for Solaris' openat function.
+# serial 29
+# See if we need to use our replacement for Solaris' openat et al functions.
 
-dnl Copyright (C) 2004 Free Software Foundation, Inc.
+dnl Copyright (C) 2004-2010 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.
@@ -10,19 +10,117 @@ dnl with or without modifications, as long as this notice is preserved.
 
 AC_DEFUN([gl_FUNC_OPENAT],
 [
-  AC_LIBSOURCES([openat.c, openat.h])
+  AC_REQUIRE([gl_FCNTL_H_DEFAULTS])
+  GNULIB_OPENAT=1
+
+  AC_REQUIRE([gl_SYS_STAT_H_DEFAULTS])
+  GNULIB_FCHMODAT=1
+  GNULIB_FSTATAT=1
+  GNULIB_MKDIRAT=1
+
+  AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
+  GNULIB_FCHOWNAT=1
+  GNULIB_UNLINKAT=1
+
+  AC_LIBOBJ([openat-proc])
   AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
-  AC_REPLACE_FUNCS(openat)
-  case $ac_cv_func_openat in
-  yes) ;;
+  AC_CHECK_FUNCS_ONCE([lchmod])
+  AC_REPLACE_FUNCS([fchmodat fstatat mkdirat openat unlinkat])
+  AC_REQUIRE([AC_FUNC_LSTAT_FOLLOWS_SLASHED_SYMLINK])
+  AC_REQUIRE([gl_FUNC_UNLINK])
+  case $ac_cv_func_openat+$ac_cv_func_lstat_dereferences_slashed_symlink in
+  yes+yes)
+    # GNU/Hurd has unlinkat, but it has the same bug as unlink.
+    if test $REPLACE_UNLINK = 1; then
+      AC_LIBOBJ([unlinkat])
+      REPLACE_UNLINKAT=1
+    fi ;;
+  yes+*)
+    # Solaris 9 has *at functions, but uniformly mishandles trailing
+    # slash in all of them.
+    AC_LIBOBJ([openat])
+    REPLACE_OPENAT=1
+    AC_LIBOBJ([fstatat])
+    REPLACE_FSTATAT=1
+    AC_LIBOBJ([unlinkat])
+    REPLACE_UNLINKAT=1
+    ;;
   *)
-    AC_DEFINE([__OPENAT_PREFIX], [[rpl_]],
-      [Define to rpl_ if the openat replacement function should be used.])
+    HAVE_OPENAT=0
+    HAVE_UNLINKAT=0 # No known system with unlinkat but not openat
+    HAVE_FSTATAT=0 # No known system with fstatat but not openat
     gl_PREREQ_OPENAT;;
   esac
+  if test $ac_cv_func_fchmodat != yes; then
+    HAVE_FCHMODAT=0
+  fi
+  if test $ac_cv_func_mkdirat != yes; then
+    HAVE_MKDIRAT=0
+  fi
+  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"
+     ln -s conftest.no-such $gl_dangle
+     AC_RUN_IFELSE(
+       [AC_LANG_SOURCE(
+          [[
+#include <fcntl.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <sys/types.h>
+int
+main ()
+{
+  return (fchownat (AT_FDCWD, "$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],
+[
+  AC_REQUIRE([gl_FUNC_CHOWN])
+  AC_CHECK_FUNC([fchownat],
+    [gl_FUNC_FCHOWNAT_DEREF_BUG([
+      REPLACE_FCHOWNAT=1
+      AC_DEFINE([FCHOWNAT_NOFOLLOW_BUG], [1],
+                [Define to 1 if your platform has fchownat, but it cannot
+                 perform lchown tasks.])
+      if test $REPLACE_CHOWN = 1; then
+        REPLACE_FCHOWNAT=1
+      fi])],
+    [HAVE_FCHOWNAT=0])
+  if test $HAVE_FCHOWNAT = 0 || test $REPLACE_FCHOWNAT = 1; then
+    AC_LIBOBJ([fchownat])
+  fi
 ])
 
 AC_DEFUN([gl_PREREQ_OPENAT],
 [
-  AC_REQUIRE([gl_SAVE_CWD])
+  AC_REQUIRE([AC_C_INLINE])
+  AC_REQUIRE([gl_PROMOTED_TYPE_MODE_T])
+  :
 ])