+ 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 if the fchownat function, like chown, has the trailing slash bug,
+# 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