POSIX: fix logging of messages with file descriptors

Sometimes the IPC Message logging code parses the message multiple
times. When we have a side array of FileDescriptors, this fails
because the array is consumed by the first parse and so the second
parse fails - causing a DCHECK failure.

Although we could write a system to all the side array to be parsed
multiple times, this code is only enabled in debugging mode and the
only advantage would be that we could log the actual descriptor
numbers. It doesn't appear that the performance hit would be
worthwhile.

Thus, we make hitting the end of the descriptor array a non-fatal
error. The returned descriptor will be -1. Since we have the number of
descriptors in the message header, the only case where this could mask
an actual issue would be where the browser and renderer disagree on
the structure of a given message. However, such a mismatch will
probably cause much more grevious errors anyway.


git-svn-id: svn://svn.chromium.org/chrome/trunk/src@9472 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 7 insertions, 3 deletions

diff --git a/chrome/common/ipc_message_utils.h b/chrome/common/ipc_message_utils.h
index 7887dcc..bd38df0 100644
--- a/chrome/common/ipc_message_utils.h
+++ b/chrome/common/ipc_message_utils.h
@@ -681,13 +681,17 @@ struct ParamTraits<FileDescriptor> {
     r->auto_close = false;
     r->fd = m->descriptor_set()->NextDescriptor();
 
-    return r->fd >= 0;
+    // We always return true here because some of the IPC message logging
+    // functions want to parse the message multiple times. On the second and
+    // later attempts, the descriptor_set will be empty and so will return -1,
+    // however, failing to parse at log time is a fatal error.
+    return true;
   }
   static void Log(const param_type& p, std::wstring* l) {
     if (p.auto_close) {
-      l->append(StringPrintf(L"FD(%d auto-close)", p.fd));
+      l->append(L"FD(auto-close)");
     } else {
-      l->append(StringPrintf(L"FD(%d)", p.fd));
+      l->append(L"FD");
     }
   }
 };