X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;ds=sidebyside;f=m4%2Flstat.m4;h=fe161d40101dce4335e51d747acd00090d9cd215;hb=0b3a22be69e9afb311ae8b64e141155b3d948f14;hp=8ef73b3220a76ec50f5584f09c41a048b80f3e64;hpb=6fe8d7498529e40705598c70355fd2f38efc7aea;p=gnulib.git

diff --git a/m4/lstat.m4 b/m4/lstat.m4
index 8ef73b322..fe161d401 100644
--- a/m4/lstat.m4
+++ b/m4/lstat.m4
@@ -1,40 +1,70 @@
-#serial 7
+# serial 23
+
+# Copyright (C) 1997-2001, 2003-2011 Free Software Foundation, Inc.
+#
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
 
 dnl From Jim Meyering.
-dnl Determine whether lstat has the bug that it succeeds when given the
-dnl zero-length file name argument.  The lstat from SunOS4.1.4 and the Hurd
-dnl (as of 1998-11-01) do this.
-dnl
-dnl If it does, then define HAVE_LSTAT_EMPTY_STRING_BUG and arrange to
-dnl compile the wrapper function.
-dnl
 
-AC_DEFUN([jm_FUNC_LSTAT],
+AC_DEFUN([gl_FUNC_LSTAT],
 [
- AC_REQUIRE([AC_FUNC_LSTAT_FOLLOWS_SLASHED_SYMLINK])
- AC_CACHE_CHECK([whether lstat accepts an empty string],
-  jm_cv_func_lstat_empty_string_bug,
-  [AC_TRY_RUN([
-#   include <sys/types.h>
-#   include <sys/stat.h>
-
-    int
-    main ()
-    {
-      struct stat sbuf;
-      exit (lstat ("", &sbuf) ? 1 : 0);
-    }
-	  ],
-	 jm_cv_func_lstat_empty_string_bug=yes,
-	 jm_cv_func_lstat_empty_string_bug=no,
-	 dnl When crosscompiling, assume lstat is broken.
-	 jm_cv_func_lstat_empty_string_bug=yes)
-  ])
-  if test $jm_cv_func_lstat_empty_string_bug = yes; then
-    AC_LIBOBJ(lstat)
-    AC_DEFINE(HAVE_LSTAT_EMPTY_STRING_BUG, 1,
-[Define if lstat has the bug that it succeeds when given the zero-length
-   file name argument.  The lstat from SunOS4.1.4 and the Hurd as of 1998-11-01)
-   do this. ])
+  AC_REQUIRE([gl_SYS_STAT_H_DEFAULTS])
+  dnl If lstat does not exist, the replacement <sys/stat.h> does
+  dnl "#define lstat stat", and lstat.c is a no-op.
+  AC_CHECK_FUNCS_ONCE([lstat])
+  if test $ac_cv_func_lstat = yes; then
+    AC_REQUIRE([gl_FUNC_LSTAT_FOLLOWS_SLASHED_SYMLINK])
+    if test $gl_cv_func_lstat_dereferences_slashed_symlink = no; then
+      REPLACE_LSTAT=1
+    fi
+  else
+    HAVE_LSTAT=0
   fi
 ])
+
+# Prerequisites of lib/lstat.c.
+AC_DEFUN([gl_PREREQ_LSTAT],
+[
+  AC_REQUIRE([AC_C_INLINE])
+  :
+])
+
+AC_DEFUN([gl_FUNC_LSTAT_FOLLOWS_SLASHED_SYMLINK],
+[
+  dnl We don't use AC_FUNC_LSTAT_FOLLOWS_SLASHED_SYMLINK any more, because it
+  dnl is no longer maintained in Autoconf and because it invokes AC_LIBOBJ.
+  AC_CACHE_CHECK([whether lstat correctly handles trailing slash],
+    [gl_cv_func_lstat_dereferences_slashed_symlink],
+    [rm -f conftest.sym conftest.file
+     echo >conftest.file
+     if test "$as_ln_s" = "ln -s" && ln -s conftest.file conftest.sym; then
+       AC_RUN_IFELSE(
+         [AC_LANG_PROGRAM(
+            [AC_INCLUDES_DEFAULT],
+            [[struct stat sbuf;
+              /* Linux will dereference the symlink and fail, as required by
+                 POSIX.  That is better in the sense that it means we will not
+                 have to compile and use the lstat wrapper.  */
+              return lstat ("conftest.sym/", &sbuf) == 0;
+            ]])],
+         [gl_cv_func_lstat_dereferences_slashed_symlink=yes],
+         [gl_cv_func_lstat_dereferences_slashed_symlink=no],
+         [# When cross-compiling, be pessimistic so we will end up using the
+          # replacement version of lstat that checks for trailing slashes and
+          # calls lstat a second time when necessary.
+          gl_cv_func_lstat_dereferences_slashed_symlink=no
+         ])
+     else
+       # If the 'ln -s' command failed, then we probably don't even
+       # have an lstat function.
+       gl_cv_func_lstat_dereferences_slashed_symlink=no
+     fi
+     rm -f conftest.sym conftest.file
+    ])
+  test $gl_cv_func_lstat_dereferences_slashed_symlink = yes &&
+    AC_DEFINE_UNQUOTED([LSTAT_FOLLOWS_SLASHED_SYMLINK], [1],
+      [Define to 1 if `lstat' dereferences a symlink specified
+       with a trailing slash.])
+])