libltdl and cygwin 1.7.0

[Eric Blake]

Cygwin 1.7.0 will change the size of MAX_PATH in its headers, but the old 
cygwin_conv_to_* API silently suffers from buffer overrun if more than 256 
bytes occur in the conversion.  As a result, cygwin developers wisely 
deprecated the old API when adding the new cygwin_path_conv, and compilation 
now issues a warning (which in turn cripples -Werror builds):

libltdl/loaders/loadlibrary.c: In function `vm_open':
libltdl/loaders/loadlibrary.c:147: warning: `cygwin_conv_to_full_win32_path' is 
deprecated (declared at /usr/include/sys/cygwin.h:52)
make[2]: *** [libltdl/loaders/loadlibrary.lo] Error 1

OK to apply?


>From 2db764974e01cc576dd1bcfb7afad2ec7d64217a Mon Sep 17 00:00:00 2001
From: Eric Blake <address@hidden>
Date: Wed, 30 Apr 2008 10:49:45 -0600
Subject: [PATCH] Support cygwin 1.7.0 in loadlibrary loader.

* libltdl/m4/ltdl.m4 (LT_LIB_DLLOAD) <cygwin>: Check for modern
function.
* libltdl/loaders/loadlibrary.c (vm_open): Avoid deprecated
cygwin_conv_to_full_win32_path.

Signed-off-by: Eric Blake <address@hidden>
---
 ChangeLog                     |    8 ++++++++
 libltdl/loaders/loadlibrary.c |    9 ++++++++-
 libltdl/m4/ltdl.m4            |    3 ++-
 3 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index ca8c2a1..b3c0616 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+2008-04-30  Eric Blake  <address@hidden>
+
+       Support cygwin 1.7.0 in loadlibrary loader.
+       * libltdl/m4/ltdl.m4 (LT_LIB_DLLOAD) <cygwin>: Check for modern
+       function.
+       * libltdl/loaders/loadlibrary.c (vm_open): Avoid deprecated
+       cygwin_conv_to_full_win32_path.
+
 2008-04-29  Gary V. Vaughan  <address@hidden>
 
        New libtoolize --no-warn option and LIBTOOLIZE_OPTIONS parsing.
diff --git a/libltdl/loaders/loadlibrary.c b/libltdl/loaders/loadlibrary.c
index 609870c..6558d43 100644
--- a/libltdl/loaders/loadlibrary.c
+++ b/libltdl/loaders/loadlibrary.c
@@ -136,7 +136,14 @@ vm_open (lt_user_data LT__UNUSED loader_data, const char 
*filename,
          return 0;
        }
 
-#if defined(__CYGWIN__)
+#if HAVE_DECL_CYGWIN_CONV_PATH
+      if (cygwin_conv_path (CCP_POSIX_TO_WIN_A, filename, wpath, MAX_PATH))
+        {
+         LT__SETERROR (CANNOT_OPEN);
+         return 0;
+       }
+      len = 0;
+#elif defined(__CYGWIN__)
       cygwin_conv_to_full_win32_path (filename, wpath);
       len = 0;
 #else
diff --git a/libltdl/m4/ltdl.m4 b/libltdl/m4/ltdl.m4
index f6b1064..ed71570 100644
--- a/libltdl/m4/ltdl.m4
+++ b/libltdl/m4/ltdl.m4
@@ -711,6 +711,7 @@ beos*)
   LT_DLLOADERS="$LT_DLLOADERS ${lt_dlopen_dir+$lt_dlopen_dir/}load_add_on.la"
   ;;
 cygwin* | mingw* | os2* | pw32*)
+  AC_CHECK_DECLS([cygwin_conv_path], [], [], [[#include <sys/cygwin.h>]])
   LT_DLLOADERS="$LT_DLLOADERS ${lt_dlopen_dir+$lt_dlopen_dir/}loadlibrary.la"
   ;;
 esac
-- 
1.5.5.1