Add warning message when a managed proxy dies during configuration.

changes/bug7195

@@ -0,0 +1,4 @@
+  o Minor bugfixes:
+    - Add warning message when a managed proxy dies during
+      configuration. Fixes bug 7195; bugfix on 0.2.4.2-alpha.
+

src/common/util.c

@@ -4461,6 +4461,25 @@ tor_split_lines(smartlist_t *sl, char *buf, int len)
   return smartlist_len(sl);
 }
 
+/** Return a string corresponding to <b>stream_status</b>. */
+const char *
+stream_status_to_string(enum stream_status stream_status)
+{
+  switch (stream_status) {
+    case IO_STREAM_OKAY:
+      return "okay";
+    case IO_STREAM_EAGAIN:
+      return "temporarily unavailable";
+    case IO_STREAM_TERM:
+      return "terminated";
+    case IO_STREAM_CLOSED:
+      return "closed";
+    default:
+      tor_fragile_assert();
+      return "unknown";
+  }
+}
+
 #ifdef _WIN32
 
 /** Return a smartlist containing lines outputted from

src/common/util.h

@@ -307,6 +307,8 @@ enum stream_status {
   IO_STREAM_CLOSED
 };
 
+const char *stream_status_to_string(enum stream_status stream_status);
+
 enum stream_status get_string_from_pipe(FILE *stream, char *buf, size_t count);
 
 /** Return values from file_status(); see that function's documentation

src/or/transports.c

@@ -614,8 +614,15 @@ configure_proxy(managed_proxy_t *mp)
     tor_get_lines_from_handle(tor_process_get_stdout_pipe(mp->process_handle),
                               &stream_status);
   if (!proxy_output) { /* failed to get input from proxy */
-    if (stream_status != IO_STREAM_EAGAIN)
+    if (stream_status != IO_STREAM_EAGAIN) { /* bad stream status! */
       mp->conf_state = PT_PROTO_BROKEN;
+      log_warn(LD_GENERAL, "The communication stream of managed proxy '%s' "
+               "is '%s'. Most probably the managed proxy stopped running. "
+               "This might be a bug of the managed proxy, a bug of Tor, or "
+               "a misconfiguration. Please enable logging on your managed "
+               "proxy and check the logs for errors.",
+               mp->argv[0], stream_status_to_string(stream_status));
+    }
 
     goto done;
   }