getcwd on mingw

[Eric Blake]

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getcwd does not need replacement on mingw, even though it fails runtime
tests in getcwd.m4, and even though cross-compilation was pessimistic.
This fixes things, and adds a simple unit test to prove that getcwd is
behaving reasonably.

- --
Don't work too hard, make some time for fun as well!

Eric Blake             address@hidden
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>From e2b8816f0465fa211eb5b49ecbeb78e9c3cc46b8 Mon Sep 17 00:00:00 2001
From: Eric Blake <address@hidden>
Date: Wed, 9 Sep 2009 20:52:26 -0600
Subject: [PATCH] getcwd: port to mingw

* m4/getcwd.m4 (gl_FUNC_GETCWD): Mingw directories are very
different from the POSIX assumptions made throughout the getcwd
module; fortunately, the mingw getcwd does not need replacement.
(gl_FUNC_GETCWD_NULL): Skip test on mingw.
* modules/getcwd-tests: New test.
* tests/test-getcwd.c: Likewise.

Signed-off-by: Eric Blake <address@hidden>
---
 ChangeLog            |    8 +++++
 m4/getcwd.m4         |   44 ++++++++++++++++++--------
 modules/getcwd-tests |   10 ++++++
 tests/test-getcwd.c  |   83 ++++++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 131 insertions(+), 14 deletions(-)
 create mode 100644 modules/getcwd-tests
 create mode 100644 tests/test-getcwd.c

diff --git a/ChangeLog b/ChangeLog
index 957a1f6..b5b4494 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,13 @@
 2009-09-09  Eric Blake  <address@hidden>

+       getcwd: port to mingw
+       * m4/getcwd.m4 (gl_FUNC_GETCWD): Mingw directories are very
+       different from the POSIX assumptions made throughout the getcwd
+       module; fortunately, the mingw getcwd does not need replacement.
+       (gl_FUNC_GETCWD_NULL): Skip test on mingw.
+       * modules/getcwd-tests: New test.
+       * tests/test-getcwd.c: Likewise.
+
        link: fix platform bugs
        * m4/link.m4 (gl_FUNC_LINK): Detect Solaris and Cygwin bugs.
        * lib/link.c (link): Work around them.  Fix related mingw bug.
diff --git a/m4/getcwd.m4 b/m4/getcwd.m4
index 6ebe2fc..4b8c4c6 100644
--- a/m4/getcwd.m4
+++ b/m4/getcwd.m4
@@ -1,53 +1,69 @@
 # getcwd.m4 - check for working getcwd that is compatible with glibc

-# Copyright (C) 2001, 2003, 2004, 2005, 2006, 2007 Free Software Foundation, 
Inc.
+# Copyright (C) 2001, 2003, 2004, 2005, 2006, 2007, 2009 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

 AC_DEFUN([gl_FUNC_GETCWD_NULL],
   [
    AC_CACHE_CHECK([whether getcwd (NULL, 0) allocates memory for result],
      [gl_cv_func_getcwd_null],
-     [AC_TRY_RUN(
-        [
-#       include <stdlib.h>
+     [AC_RUN_IFELSE([AC_LANG_PROGRAM([[
 #       include <unistd.h>
 #       ifndef getcwd
         char *getcwd ();
 #       endif
-        int
-        main ()
-        {
+]], [[
+#if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
+/* mingw cwd does not start with '/', but getcwd does allocate.  */
+#else
           if (chdir ("/") != 0)
-            exit (1);
+            return 1;
           else
             {
               char *f = getcwd (NULL, 0);
-              exit (! (f && f[0] == '/' && !f[1]));
+              return ! (f && f[0] == '/' && !f[1]);
             }
-        }],
+#endif
+        ]])],
        [gl_cv_func_getcwd_null=yes],
        [gl_cv_func_getcwd_null=no],
-       [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
+       ]])])
 ])

 AC_DEFUN([gl_FUNC_GETCWD],
 [
   AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
   AC_REQUIRE([gl_FUNC_GETCWD_NULL])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles

   gl_abort_bug=no
-  case $gl_cv_func_getcwd_null in
-  yes)
+  case $gl_cv_func_getcwd_null,$host_os in
+  *,mingw*)
+    gl_cv_func_getcwd_path_max=yes;;
+  yes,*)
     gl_FUNC_GETCWD_PATH_MAX
     gl_FUNC_GETCWD_ABORT_BUG([gl_abort_bug=yes]);;
   esac

   case $gl_cv_func_getcwd_null,$gl_cv_func_getcwd_path_max,$gl_abort_bug in
-  yes,yes,no) ;;
+  *yes,yes,no) ;;
   *)
     REPLACE_GETCWD=1
     AC_LIBOBJ([getcwd])
diff --git a/modules/getcwd-tests b/modules/getcwd-tests
new file mode 100644
index 0000000..d7eee2b
--- /dev/null
+++ b/modules/getcwd-tests
@@ -0,0 +1,10 @@
+Files:
+tests/test-getcwd.c
+
+Depends-on:
+
+configure.ac:
+
+Makefile.am:
+TESTS += test-getcwd
+check_PROGRAMS += test-getcwd
diff --git a/tests/test-getcwd.c b/tests/test-getcwd.c
new file mode 100644
index 0000000..2733e4f
--- /dev/null
+++ b/tests/test-getcwd.c
@@ -0,0 +1,83 @@
+/* Test of getcwd() function.
+   Copyright (C) 2009 Free Software Foundation, Inc.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#include <config.h>
+
+#include <unistd.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define ASSERT(expr) \
+  do                                                                         \
+    {                                                                        \
+      if (!(expr))                                                           \
+        {                                                                    \
+          fprintf (stderr, "%s:%d: assertion failed\n", __FILE__, __LINE__); \
+          fflush (stderr);                                                   \
+          abort ();                                                          \
+        }                                                                    \
+    }                                                                        \
+  while (0)
+
+int
+main (int argc, char **argv)
+{
+  char *pwd1;
+  char *pwd2;
+  /* If the user provides an argument, attempt to chdir there first.  */
+  if (1 < argc)
+    {
+      if (chdir (argv[1]) == 0)
+       printf ("changed to directory %s\n", argv[1]);
+    }
+
+  pwd1 = getcwd (NULL, 0);
+  ASSERT (pwd1 && *pwd1);
+  if (1 < argc)
+    printf ("cwd=%s\n", pwd1);
+
+  /* Make sure the result is usable.  */
+  ASSERT (chdir (pwd1) == 0);
+  ASSERT (chdir ("././.") == 0);
+
+  /* Make sure that result is normalized.  */
+  pwd2 = getcwd (NULL, 0);
+  ASSERT (pwd2);
+  ASSERT (strcmp (pwd1, pwd2) == 0);
+  free (pwd2);
+  {
+    size_t len = strlen (pwd1);
+    size_t i = len - 10;
+    if (i < 0)
+      i = 0;
+    pwd2 = malloc (len + 2);
+    for ( ; i < len; i++)
+      ASSERT (getcwd (pwd2, i) == NULL);
+    pwd2 = getcwd (pwd2, len + 1);
+    ASSERT (pwd2);
+    pwd2[len] = '/';
+    pwd2[len + 1] = '\0';
+  }
+  ASSERT (strstr (pwd2, "/./") == NULL);
+  ASSERT (strstr (pwd2, "/../") == NULL);
+
+  free (pwd1);
+  free (pwd2);
+
+  return 0;
+}
-- 
1.6.3.3.334.g916e1