-#serial 4
-
-dnl From Jim Meyering.
-dnl Determine whether chown accepts arguments of -1 for uid and gid.
-dnl If it doesn't, arrange to use the replacement function.
-dnl
-
-AC_DEFUN(jm_FUNC_CHOWN,
-[AC_REQUIRE([AC_TYPE_UID_T])dnl
- test -z "$ac_cv_header_unistd_h" \
- && AC_CHECK_HEADERS(unistd.h)
- AC_CACHE_CHECK([for working chown], jm_cv_func_working_chown,
- [AC_TRY_RUN([
-# include <sys/types.h>
-# include <sys/stat.h>
-# include <fcntl.h>
-# ifdef HAVE_UNISTD_H
-# include <unistd.h>
-# endif
-
- int
- main ()
- {
- char *f = "conftestchown";
- struct stat before, after;
-
- if (creat (f, 0600) < 0)
- exit (1);
- if (stat (f, &before) < 0)
- exit (1);
- if (chown (f, (uid_t) -1, (gid_t) -1) == -1)
- exit (1);
- if (stat (f, &after) < 0)
- exit (1);
- exit ((before.st_uid == after.st_uid
- && before.st_gid == after.st_gid) ? 0 : 1);
- }
- ],
- jm_cv_func_working_chown=yes,
- jm_cv_func_working_chown=no,
- dnl When crosscompiling, assume chown is broken.
- jm_cv_func_working_chown=no)
- ])
- if test $jm_cv_func_working_chown = no; then
- AC_SUBST(LIBOBJS)
- LIBOBJS="$LIBOBJS chown.$ac_objext"
- AC_DEFINE_UNQUOTED(chown, rpl_chown,
- [Define to rpl_chown if the replacement function should be used.])
+#serial 17
+# Determine whether we need the chown wrapper.
+
+dnl Copyright (C) 1997, 1998, 1999, 2000, 2001, 2003, 2004, 2005, 2007 Free
+dnl 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.
+
+# chown should accept arguments of -1 for uid and gid, and it should
+# dereference symlinks. If it doesn't, arrange to use the replacement
+# function.
+
+# From Jim Meyering.
+
+AC_DEFUN([gl_FUNC_CHOWN],
+[
+ AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
+ AC_REQUIRE([AC_TYPE_UID_T])
+ AC_REQUIRE([AC_FUNC_CHOWN])
+ AC_REQUIRE([gl_FUNC_CHOWN_FOLLOWS_SYMLINK])
+
+ 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.])
+ fi
+
+ # If chown has either of the above problems, then we need the wrapper.
+ if test $ac_cv_func_chown_works$gl_cv_func_chown_follows_symlink = yesyes; then
+ : # no wrapper needed
+ else
+ REPLACE_CHOWN=1
+ AC_LIBOBJ(chown)
+ gl_PREREQ_CHOWN
fi
])
+
+# Determine whether chown follows symlinks (it should).
+AC_DEFUN([gl_FUNC_CHOWN_FOLLOWS_SYMLINK],
+[
+ AC_CACHE_CHECK(
+ [whether chown(2) dereferences symlinks],
+ gl_cv_func_chown_follows_symlink,
+ [
+ AC_RUN_IFELSE([AC_LANG_SOURCE([[
+#include <unistd.h>
+#include <stdlib.h>
+#include <errno.h>
+
+ int
+ main ()
+ {
+ char const *dangling_symlink = "conftest.dangle";
+
+ unlink (dangling_symlink);
+ if (symlink ("conftest.no-such", dangling_symlink))
+ abort ();
+
+ /* Exit successfully on a conforming system,
+ i.e., where chown must fail with ENOENT. */
+ exit ( ! (chown (dangling_symlink, getuid (), getgid ()) != 0
+ && errno == ENOENT));
+ }
+ ]])],
+ [gl_cv_func_chown_follows_symlink=yes],
+ [gl_cv_func_chown_follows_symlink=no],
+ [gl_cv_func_chown_follows_symlink=yes]
+ )
+ ]
+ )
+
+ if test $gl_cv_func_chown_follows_symlink = no; then
+ AC_DEFINE(CHOWN_MODIFIES_SYMLINK, 1,
+ [Define if chown modifies symlinks.])
+ fi
+])
+
+# Prerequisites of lib/chown.c.
+AC_DEFUN([gl_PREREQ_CHOWN],
+[
+ AC_CHECK_FUNC([fchown], , [AC_LIBOBJ(fchown-stub)])
+])