start tracking the 'broken pipe' error

svn:r1261

src/or/buffers.c

@@ -253,6 +253,7 @@ int flush_buf(int s, buf_t *buf, int *buf_flushlen)
   write_result = send(s, buf->mem, *buf_flushlen, 0);
   if (write_result < 0) {
     if(!ERRNO_EAGAIN(errno)) { /* it's a real error */
+      assert(errno != EPIPE); /* get a stack trace to find epipe bugs */
       return -1;
     }
 #ifdef MS_WINDOWS

src/or/main.c

@@ -631,6 +631,9 @@ static void catch(int the_signal) {
       if(options.PidFile)
         unlink(options.PidFile);
       exit(0);
+    case SIGPIPE:
+      log(LOG_WARN,"Bug: caught sigpipe. Ignoring.");
+      break;
     case SIGHUP:
       please_reset = 1;
       break;
@@ -751,6 +754,7 @@ int tor_main(int argc, char *argv[]) {
 #ifndef MS_WINDOWS /* do signal stuff only on unix */
   signal (SIGINT,  catch); /* catch kills so we can exit cleanly */
   signal (SIGTERM, catch);
+  signal (SIGPIPE, catch);
   signal (SIGUSR1, catch); /* to dump stats */
   signal (SIGHUP,  catch); /* to reload directory */
   signal (SIGCHLD, catch); /* for exiting dns/cpu workers */