X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=m4%2Flstat.m4;h=b9b22a6b20e096a94bac4d3a9a51a0f71aa9af90;hb=12856373f8fd28a9d4453d6df97b2fdd17ced398;hp=ea0c89494349e5e107d2c51f68aa3c2e36721fe1;hpb=40fc0427a65230122dbbf0e7c42edbe24e14602f;p=gnulib.git

diff --git a/m4/lstat.m4 b/m4/lstat.m4
index ea0c89494..b9b22a6b2 100644
--- a/m4/lstat.m4
+++ b/m4/lstat.m4
@@ -1,27 +1,69 @@
-#serial 9
+# serial 21
+
+# 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 SunOS 4.1.4 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_FUNC_LSTAT
-  dnl Note: AC_FUNC_LSTAT does AC_LIBOBJ(lstat).
-  if test $ac_cv_func_lstat_empty_string_bug = yes; then
-    gl_PREREQ_LSTAT
+  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([AC_FUNC_LSTAT_FOLLOWS_SLASHED_SYMLINK])
+    if test $ac_cv_func_lstat_dereferences_slashed_symlink = no; then
+      dnl Note: AC_FUNC_LSTAT_FOLLOWS_SLASHED_SYMLINK does AC_LIBOBJ([lstat]).
+      REPLACE_LSTAT=1
+    fi
+    # Prerequisites of lib/lstat.c.
+    AC_REQUIRE([AC_C_INLINE])
+  else
+    HAVE_LSTAT=0
   fi
 ])
 
-# Prerequisites of lib/lstat.c.
-AC_DEFUN([gl_PREREQ_LSTAT],
+# Redefine AC_FUNC_LSTAT_FOLLOWS_SLASHED_SYMLINK, because it is no longer
+# maintained in Autoconf.
+AC_DEFUN([AC_FUNC_LSTAT_FOLLOWS_SLASHED_SYMLINK],
 [
-  AC_REQUIRE([AC_HEADER_STAT])
-  AC_CHECK_HEADERS_ONCE(stdlib.h)
-  AC_CHECK_DECLS_ONCE(free)
+  AC_CACHE_CHECK([whether lstat correctly handles trailing slash],
+    [ac_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;
+            ]])],
+         [ac_cv_func_lstat_dereferences_slashed_symlink=yes],
+         [ac_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.
+          ac_cv_func_lstat_dereferences_slashed_symlink=no
+         ])
+     else
+       # If the 'ln -s' command failed, then we probably don't even
+       # have an lstat function.
+       ac_cv_func_lstat_dereferences_slashed_symlink=no
+     fi
+     rm -f conftest.sym conftest.file
+    ])
+  test $ac_cv_func_lstat_dereferences_slashed_symlink = yes &&
+    AC_DEFINE_UNQUOTED([LSTAT_FOLLOWS_SLASHED_SYMLINK], [1],
+      [Define to 1 if `lstat' dereferences a symlink specified
+       with a trailing slash.])
+  if test "x$ac_cv_func_lstat_dereferences_slashed_symlink" = xno; then
+    AC_LIBOBJ([lstat])
+  fi
 ])