chown: work around OpenBSD bug

[gnulib.git] / m4 / chown.m4

diff --git a/m4/chown.m4 b/m4/chown.m4
index 5bedfa1..0dced4b 100644 (file)
--- a/m4/chown.m4
+++ b/m4/chown.m4
@@ -1,4 +1,4 @@
-# serial 21
+# serial 22
 # Determine whether we need the chown wrapper.
 
 dnl Copyright (C) 1997-2001, 2003-2005, 2007, 2009
@@ -22,20 +22,27 @@ AC_DEFUN_ONCE([gl_FUNC_CHOWN],
   AC_REQUIRE([gl_FUNC_CHOWN_FOLLOWS_SYMLINK])
   AC_CHECK_FUNCS_ONCE([chown fchown])
 
+  dnl mingw lacks chown altogether.
   if test $ac_cv_func_chown = no; then
     HAVE_CHOWN=0
     AC_LIBOBJ([chown])
   else
+    dnl Some old systems treated chown like lchown.
     if test $gl_cv_func_chown_follows_symlink = no; then
       REPLACE_CHOWN=1
       AC_LIBOBJ([chown])
     fi
+
+    dnl Some old systems tried to use uid/gid -1 literally.
     if test $ac_cv_func_chown_works = no; then
       AC_DEFINE([CHOWN_FAILS_TO_HONOR_ID_OF_NEGATIVE_ONE], [1],
         [Define if chown is not POSIX compliant regarding IDs of -1.])
       REPLACE_CHOWN=1
       AC_LIBOBJ([chown])
     fi
+
+    dnl Solaris 9 ignores trailing slash.
+    dnl FreeBSD 7.2 mishandles trailing slash on symlinks.
     AC_CACHE_CHECK([whether chown honors trailing slash],
       [gl_cv_func_chown_slash_works],
       [touch conftest.file && rm -f conftest.link
@@ -52,10 +59,39 @@ AC_DEFUN_ONCE([gl_FUNC_CHOWN],
       rm -f conftest.link conftest.file])
     if test "$gl_cv_func_chown_slash_works" != yes; then
       AC_DEFINE([CHOWN_TRAILING_SLASH_BUG], [1],
-        [Define if chown mishandles trailing slash.])
+        [Define to 1 if chown mishandles trailing slash.])
       REPLACE_CHOWN=1
       AC_LIBOBJ([chown])
     fi
+
+    dnl OpenBSD fails to update ctime if ownership does not change.
+    AC_CACHE_CHECK([whether chown always updates ctime],
+      [gl_cv_func_chown_ctime_works],
+      [AC_RUN_IFELSE([AC_LANG_PROGRAM([[
+#include <unistd.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <sys/stat.h>
+]], [[    struct stat st1, st2;
+          if (close (creat ("conftest.file", 0600))) return 1;
+          if (stat ("conftest.file", &st1)) return 2;
+          sleep (1);
+          if (chown ("conftest.file", st1.st_uid, st1.st_gid)) return 3;
+          if (stat ("conftest.file", &st2)) return 4;
+          if (st2.st_ctime <= st1.st_ctime) return 5;
+        ]])],
+        [gl_cv_func_chown_ctime_works=yes],
+        [gl_cv_func_chown_ctime_works=no],
+        [gl_cv_func_chown_ctime_works="guessing no"])
+      rm -f conftest.file])
+    if test "$gl_cv_func_chown_ctime_works" != yes; then
+      AC_DEFINE([CHOWN_CHANGE_TIME_BUG], [1], [Define to 1 if chown fails
+        to change ctime when at least one argument was not -1.])
+      REPLACE_CHOWN=1
+      AC_LIBOBJ([chown])
+    fi
+
     if test $REPLACE_CHOWN = 1 && test $ac_cv_func_fchown = no; then
       AC_LIBOBJ([fchown-stub])
     fi