NEWS.stable: log cherry-pick [79aac72]->[cc1a9b7] canonicalize-lgpl: use common idiom

[gnulib.git] / m4 / getcwd.m4

diff --git a/m4/getcwd.m4 b/m4/getcwd.m4
index 4b8c4c6..eb2c9d9 100644 (file)
--- a/m4/getcwd.m4
+++ b/m4/getcwd.m4
@@ -1,52 +1,85 @@
 # getcwd.m4 - check for working getcwd that is compatible with glibc
 
-# Copyright (C) 2001, 2003, 2004, 2005, 2006, 2007, 2009 Free Software
-# Foundation, Inc.
+# Copyright (C) 2001, 2003-2007, 2009-2011 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.
 
 # Written by Paul Eggert.
-# serial 2
+# serial 6
 
 AC_DEFUN([gl_FUNC_GETCWD_NULL],
   [
+   AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
    AC_CACHE_CHECK([whether getcwd (NULL, 0) allocates memory for result],
      [gl_cv_func_getcwd_null],
      [AC_RUN_IFELSE([AC_LANG_PROGRAM([[
-#       include <unistd.h>
-#       ifndef getcwd
-        char *getcwd ();
-#       endif
+#        include <unistd.h>
+#        ifndef getcwd
+         char *getcwd ();
+#        endif
 ]], [[
 #if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
-/* mingw cwd does not start with '/', but getcwd does allocate.  */
+/* mingw cwd does not start with '/', but getcwd does allocate.
+   However, mingw fails to honor non-zero size.  */
 #else
-          if (chdir ("/") != 0)
-            return 1;
-          else
-            {
-              char *f = getcwd (NULL, 0);
-              return ! (f && f[0] == '/' && !f[1]);
-            }
+           if (chdir ("/") != 0)
+             return 1;
+           else
+             {
+               char *f = getcwd (NULL, 0);
+               if (! f)
+                 return 2;
+               if (f[0] != '/')
+                 return 3;
+               if (f[1] != '\0')
+                 return 4;
+               return 0;
+             }
 #endif
-        ]])],
-       [gl_cv_func_getcwd_null=yes],
-       [gl_cv_func_getcwd_null=no],
-       [[
+         /* If size is non-zero, allocation must fail if size is too small */
+         if (getcwd (NULL, 1))
+           return 5;
+         ]])],
+        [gl_cv_func_getcwd_null=yes],
+        [gl_cv_func_getcwd_null=no],
+        [[
        case "$host_os" in
                                # Guess yes on glibc systems.
          *-gnu*)               gl_cv_func_getcwd_null="guessing yes";;
                                # Guess yes on Cygwin.
          cygwin*)              gl_cv_func_getcwd_null="guessing yes";;
-                               # Guess yes on mingw.
-         mingw*)               gl_cv_func_getcwd_null="guessing yes";;
                                # If we don't know, assume the worst.
          *)                    gl_cv_func_getcwd_null="guessing no";;
        esac
-       ]])])
+        ]])])
 ])
 
+
+dnl Guarantee that getcwd will malloc with a NULL first argument.  Assumes
+dnl that either the system getcwd is robust, or that calling code is okay
+dnl with spurious failures when run from a directory with an absolute name
+dnl larger than 4k bytes.
+dnl
+dnl Assumes that getcwd exists; if you are worried about obsolete
+dnl platforms that lacked getcwd(), then you need to use the GPL module.
+AC_DEFUN([gl_FUNC_GETCWD_LGPL],
+[
+  AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
+  AC_REQUIRE([gl_FUNC_GETCWD_NULL])
+
+  case $gl_cv_func_getcwd_null in
+  *yes) ;;
+  *)
+    dnl Minimal replacement
+    REPLACE_GETCWD=1
+    AC_LIBOBJ([getcwd-lgpl])
+    ;;
+  esac
+])
+
+dnl Check for all known getcwd bugs; useful for a program likely to be
+dnl executed from an arbitrary location.
 AC_DEFUN([gl_FUNC_GETCWD],
 [
   AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
@@ -65,13 +98,14 @@ AC_DEFUN([gl_FUNC_GETCWD],
   case $gl_cv_func_getcwd_null,$gl_cv_func_getcwd_path_max,$gl_abort_bug in
   *yes,yes,no) ;;
   *)
+    dnl Full replacement, overrides LGPL replacement.
     REPLACE_GETCWD=1
     AC_LIBOBJ([getcwd])
     gl_PREREQ_GETCWD;;
   esac
 ])
 
-# Prerequisites of lib/getcwd.c.
+# Prerequisites of lib/getcwd.c, when full replacement is in effect.
 AC_DEFUN([gl_PREREQ_GETCWD],
 [
   AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])