From a83870ef9d1758de371551844efa4f17dda71581 Mon Sep 17 00:00:00 2001
From: Matthias Bolte <photron@users.sourceforge.net>
Date: Fri, 19 Nov 2010 13:31:34 -0800
Subject: [PATCH] Detect socket errors in GnuTLS on Windows

On Windows, translate WSAGetLastError() to errno values as GNU
TLS does it internally, too. This is necessary because send() and
recv() on Windows don't set errno when they fail but GNU TLS
expects a proper errno value.

Bug: http://curl.haxx.se/bug/view.cgi?id=3110991
---
 RELEASE-NOTES |  3 ++-
 lib/gtls.c    | 41 +++++++++++++++++++++++++++++++++++++++--
 2 files changed, 41 insertions(+), 3 deletions(-)

diff --git a/RELEASE-NOTES b/RELEASE-NOTES
index f23e2f3..6e783c2 100644
--- a/RELEASE-NOTES
+++ b/RELEASE-NOTES
@@ -31,6 +31,7 @@ This release includes the following bugfixes:
  o krb5: Use GSS_ERROR to check for error
  o TFTP: resend the correct data
  o configure: fix autoconf 2.68 warning: no AC_LANG_SOURCE call detected
+ o GnuTLS: now detects socket errors on Windows
 
 This release includes the following known bugs:
 
@@ -41,6 +42,6 @@ advice from friends like these:
 
  Dan Fandrich, Guenter Knauf, Pat Ray, Hongli Lai, Kamil Dudka,
  Stefan Tomanek, Alfred Gebert, Yang Tse, Julien Chaffraix, Adam Light,
- Rutger Hofman
+ Rutger Hofman, Matthias Bolte
 
         Thanks! (and sorry if I forgot to mention someone)
diff --git a/lib/gtls.c b/lib/gtls.c
index 84410ed..93bb91d 100644
--- a/lib/gtls.c
+++ b/lib/gtls.c
@@ -85,15 +85,52 @@ static bool gtls_inited = FALSE;
  * We use custom functions rather than the GNU TLS defaults because it allows
  * us to get specific about the fourth "flags" argument, and to use arbitrary
  * private data with gnutls_transport_set_ptr if we wish.
+ *
+ * On Windows translate WSAGetLastError() to errno values as GNU TLS does it
+ * internally too. This is necessary because send() and recv() on Windows
+ * don't set errno when they fail but GNU TLS expects a proper errno value.
+ *
+ * Use gnutls_transport_set_global_errno() like the GNU TLS documentation
+ * suggests to avoid problems with different errno variables when GNU TLS and
+ * curl are linked to different versions of msvcrt.dll.
  */
+#ifdef USE_WINSOCK
+static void translate_wsa_to_errno(void)
+{
+  switch(WSAGetLastError()) {
+  case WSAEWOULDBLOCK:
+    gnutls_transport_set_global_errno(EAGAIN);
+    break;
+  case WSAEINTR:
+    gnutls_transport_set_global_errno(EINTR);
+    break;
+  default:
+    gnutls_transport_set_global_errno(EIO);
+    break;
+  }
+}
+#endif
+
 static ssize_t Curl_gtls_push(void *s, const void *buf, size_t len)
 {
-  return swrite(GNUTLS_POINTER_TO_INT_CAST(s), buf, len);
+  ssize_t ret = swrite(GNUTLS_POINTER_TO_INT_CAST(s), buf, len);
+#ifdef USE_WINSOCK
+  if(ret < 0) {
+    translate_wsa_to_errno();
+  }
+#endif
+  return ret;
 }
 
 static ssize_t Curl_gtls_pull(void *s, void *buf, size_t len)
 {
-  return sread(GNUTLS_POINTER_TO_INT_CAST(s), buf, len);
+  ssize_t ret = sread(GNUTLS_POINTER_TO_INT_CAST(s), buf, len);
+#ifdef USE_WINSOCK
+  if(ret < 0) {
+    translate_wsa_to_errno();
+  }
+#endif
+  return ret;
 }
 
 /* Curl_gtls_init()
-- 
2.7.4