From: Eric Blake <eblake@redhat.com>
Date: Thu, 28 Apr 2011 02:40:21 +0000 (-0600)
Subject: getcwd: fix mingw bugs
X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=8585ce2ff5698c650ba5d5e3bb99763654ad62e8;p=pspp

getcwd: fix mingw bugs

On mingw, getcwd(NULL,1) succeeds, even though glibc documents that
with a non-zero size, the allocation will not exceed that many bytes.

On mingw, getcwd has the wrong signature.  However, we don't have
to check for this if anything else triggers the replacement.

Also, fix a type bug that crept into the original getcwd-lgpl commit.

* m4/getcwd.m4 (gl_FUNC_GETCWD_NULL): Detect one mingw bug.
* doc/posix-functions/getcwd.texi (getcwd): Document the problems.
* lib/getcwd-lgpl.c (rpl_getcwd): Fix return type.

Signed-off-by: Eric Blake <eblake@redhat.com>
---

diff --git a/ChangeLog b/ChangeLog
index f20299f0f7..8dae3ab1f4 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2011-04-27  Eric Blake  <eblake@redhat.com>
+
+	getcwd: fix mingw bugs
+	* m4/getcwd.m4 (gl_FUNC_GETCWD_NULL): Detect one mingw bug.
+	* doc/posix-functions/getcwd.texi (getcwd): Document the problems.
+	* lib/getcwd-lgpl.c (rpl_getcwd): Fix return type.
+
 2011-04-27  Bruno Haible  <bruno@clisp.org>
 
 	mkstemps: Ensure declaration on MacOS X 10.5.
diff --git a/doc/posix-functions/getcwd.texi b/doc/posix-functions/getcwd.texi
index a8dba967ec..1f6dd187d2 100644
--- a/doc/posix-functions/getcwd.texi
+++ b/doc/posix-functions/getcwd.texi
@@ -11,7 +11,12 @@ Portability problems fixed by either Gnulib module @code{getcwd} or
 @itemize
 @item
 On glibc platforms, @code{getcwd (NULL, n)} allocates memory for the result.
-On other platforms, this call is not allowed.
+On some other platforms, this call is not allowed.  Conversely, mingw fails
+to honor non-zero @code{n}.
+@item
+On some platforms, the prototype for @code{getcwd} uses @code{int}
+instead of @code{size_t} for the size argument:
+mingw.
 @end itemize
 
 Portability problems fixed by Gnulib module @code{getcwd}:
diff --git a/lib/getcwd-lgpl.c b/lib/getcwd-lgpl.c
index a5596f8869..53c5562357 100644
--- a/lib/getcwd-lgpl.c
+++ b/lib/getcwd-lgpl.c
@@ -53,7 +53,7 @@ rpl_getcwd (char *buf, size_t size)
       if (!buf)
         {
           errno = ENOMEM;
-          return -1;
+          return NULL;
         }
       result = getcwd (buf, size);
       if (!result)
diff --git a/m4/getcwd.m4 b/m4/getcwd.m4
index 55f937222b..eb2c9d9375 100644
--- a/m4/getcwd.m4
+++ b/m4/getcwd.m4
@@ -6,7 +6,7 @@
 # with or without modifications, as long as this notice is preserved.
 
 # Written by Paul Eggert.
-# serial 5
+# serial 6
 
 AC_DEFUN([gl_FUNC_GETCWD_NULL],
   [
@@ -20,7 +20,8 @@ AC_DEFUN([gl_FUNC_GETCWD_NULL],
 #        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;
@@ -36,6 +37,9 @@ AC_DEFUN([gl_FUNC_GETCWD_NULL],
                return 0;
              }
 #endif
+         /* 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],
@@ -45,8 +49,6 @@ AC_DEFUN([gl_FUNC_GETCWD_NULL],
          *-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