[Emacs-diffs] /srv/bzr/emacs/trunk r107812: Limit number of GnuTLS handshakes per connection.

[Ted Zlatanov]

------------------------------------------------------------
revno: 107812
committer: Ted Zlatanov <address@hidden>
branch nick: quickfixes
timestamp: Mon 2012-04-09 08:46:16 -0400
message:
  Limit number of GnuTLS handshakes per connection.
  
  * gnutls.c (gnutls_log_function2i): Convenience log function.
  (emacs_gnutls_read): Use new log functions,
  `gnutls_handshakes_tried' process member, and
  `GNUTLS_EMACS_HANDSHAKES_LIMIT' to limit the number of handshake
  attempts per process (connection).
  
  * gnutls.h: Add `GNUTLS_EMACS_HANDSHAKES_LIMIT' upper limit.  Add
  convenience `GNUTLS_LOG2i' macro.
  
  * process.c (make_process):
  * process.h: Add integer `gnutls_handshakes_tried' member to
  process struct.
modified:
  src/ChangeLog
  src/gnutls.c
  src/gnutls.h
  src/process.c
  src/process.h

=== modified file 'src/ChangeLog'
--- a/src/ChangeLog     2012-04-09 12:36:01 +0000
+++ b/src/ChangeLog     2012-04-09 12:46:16 +0000
@@ -1,3 +1,18 @@
+2012-04-09  Teodor Zlatanov  <address@hidden>
+
+       * process.c (make_process):
+       * process.h: Add integer `gnutls_handshakes_tried' member to
+       process struct.
+
+       * gnutls.h: Add `GNUTLS_EMACS_HANDSHAKES_LIMIT' upper limit.  Add
+       convenience `GNUTLS_LOG2i' macro.
+
+       * gnutls.c (gnutls_log_function2i): Convenience log function.
+       (emacs_gnutls_read): Use new log functions,
+       `gnutls_handshakes_tried' process member, and
+       `GNUTLS_EMACS_HANDSHAKES_LIMIT' to limit the number of handshake
+       attempts per process (connection).
+
 2012-04-09  Chong Yidong  <address@hidden>
 
        * eval.c (Fuser_variable_p, user_variable_p_eh)

=== modified file 'src/gnutls.c'
--- a/src/gnutls.c      2012-02-13 20:39:46 +0000
+++ b/src/gnutls.c      2012-04-09 12:46:16 +0000
@@ -247,18 +247,27 @@
 #endif /* !WINDOWSNT */
 
 
+/* Function to log a simple message.  */
 static void
 gnutls_log_function (int level, const char* string)
 {
   message ("gnutls.c: [%d] %s", level, string);
 }
 
+/* Function to log a message and a string.  */
 static void
 gnutls_log_function2 (int level, const char* string, const char* extra)
 {
   message ("gnutls.c: [%d] %s %s", level, string, extra);
 }
 
+/* Function to log a message and an integer.  */
+static void
+gnutls_log_function2i (int level, const char* string, int extra)
+{
+  message ("gnutls.c: [%d] %s %d", level, string, extra);
+}
+
 static int
 emacs_gnutls_handshake (struct Lisp_Process *proc)
 {
@@ -399,10 +408,25 @@
   ssize_t rtnval;
   gnutls_session_t state = proc->gnutls_state;
 
+  int log_level = proc->gnutls_log_level;
+
   if (proc->gnutls_initstage != GNUTLS_STAGE_READY)
     {
-      emacs_gnutls_handshake (proc);
-      return -1;
+      /* If the handshake count is under the limit, try the handshake
+         again and increment the handshake count.  This count is kept
+         per process (connection), not globally.  */
+      if (proc->gnutls_handshakes_tried < GNUTLS_EMACS_HANDSHAKES_LIMIT)
+        {
+          proc->gnutls_handshakes_tried++;
+          emacs_gnutls_handshake (proc);
+          GNUTLS_LOG2i (5, log_level, "Retried handshake", 
+                        proc->gnutls_handshakes_tried);
+          return -1;
+        }
+
+      GNUTLS_LOG (2, log_level, "Giving up on handshake; resetting retries");
+      proc->gnutls_handshakes_tried = 0;
+      return 0;
     }
   rtnval = fn_gnutls_record_recv (state, buf, nbyte);
   if (rtnval >= 0)

=== modified file 'src/gnutls.h'
--- a/src/gnutls.h      2012-01-05 09:46:05 +0000
+++ b/src/gnutls.h      2012-04-09 12:46:16 +0000
@@ -23,6 +23,9 @@
 #include <gnutls/gnutls.h>
 #include <gnutls/x509.h>
 
+/* This limits the attempts to handshake per process (connection).  */
+#define GNUTLS_EMACS_HANDSHAKES_LIMIT 100
+
 typedef enum
 {
   /* Initialization stages.  */
@@ -53,6 +56,8 @@
 
 #define GNUTLS_LOG2(level, max, string, extra) do { if (level <= max) { 
gnutls_log_function2 (level, "(Emacs) " string, extra); } } while (0)
 
+#define GNUTLS_LOG2i(level, max, string, extra) do { if (level <= max) { 
gnutls_log_function2i (level, "(Emacs) " string, extra); } } while (0)
+
 extern EMACS_INT
 emacs_gnutls_write (struct Lisp_Process *proc, const char *buf, EMACS_INT 
nbyte);
 extern EMACS_INT

=== modified file 'src/process.c'
--- a/src/process.c     2012-03-23 12:23:14 +0000
+++ b/src/process.c     2012-04-09 12:46:16 +0000
@@ -640,7 +640,10 @@
 
 #ifdef HAVE_GNUTLS
   p->gnutls_initstage = GNUTLS_STAGE_EMPTY;
+  /* Default log level.  */
   p->gnutls_log_level = 0;
+  /* GnuTLS handshakes attempted for this connection.  */
+  p->gnutls_handshakes_tried = 0;
   p->gnutls_p = 0;
   p->gnutls_state = NULL;
   p->gnutls_x509_cred = NULL;

=== modified file 'src/process.h'
--- a/src/process.h     2012-01-19 07:21:25 +0000
+++ b/src/process.h     2012-04-09 12:46:16 +0000
@@ -134,6 +134,7 @@
     gnutls_certificate_client_credentials gnutls_x509_cred;
     gnutls_anon_client_credentials_t gnutls_anon_cred;
     int gnutls_log_level;
+    int gnutls_handshakes_tried;
     int gnutls_p;
 #endif
 };