From ef71cb8b3f97b6c985bda997759ce2113cdb893e Mon Sep 17 00:00:00 2001
From: Vladimir Chtchetkine <vchtchetkine@google.com>
Date: Wed, 7 Dec 2011 10:24:33 -0800
Subject: Fixes emulator crash due to premature pipe client destruction.

The pipe client should really be closed (and destructed) only when the guest closes
its handle to the pipe. When pipe client is closed from within the emulator, it
should only notify the guest about disconnection, and wait for the guest to
explicitly close the pipe handle.

Change-Id: I6bde3ae1e05ff5dc40e9903282c3fc46df0b9b57
---
 android/hw-qemud.c | 35 ++++++++++++++++++++++++++---------
 1 file changed, 26 insertions(+), 9 deletions(-)

(limited to 'android/hw-qemud.c')

diff --git a/android/hw-qemud.c b/android/hw-qemud.c
index df9ab21..e80abed 100644
--- a/android/hw-qemud.c
+++ b/android/hw-qemud.c
@@ -824,30 +824,47 @@ _qemud_client_free(QemudClient* c)
 /* disconnect a client. this automatically frees the QemudClient.
  * note that this also removes the client from the global list
  * and from its service's list, if any.
+ * Param:
+ *  opaque - QemuClient instance
+ *  guest_close - For pipe clients control whether or not the disconnect is
+ *      caused by guest closing the pipe handle (in which case 1 is passed in
+ *      this parameter). For serial clients this parameter is ignored.
  */
 static void
-qemud_client_disconnect( void*  opaque )
+qemud_client_disconnect( void*  opaque, int guest_close )
 {
     QemudClient*  c = opaque;
 
     if (c->closing) {  /* recursive call, exit immediately */
         return;
     }
+
+    if (_is_pipe_client(c) && !guest_close) {
+        /* This is emulator component (rather than the guest) closing a pipe
+         * client. Since pipe clients are controlled strictly by the guest, we
+         * don't actually close the client here, but notify the guest about the
+         * client being disconnected. Then we will do the real client close when
+         * the guest explicitly closes the pipe, in which case this routine will
+         * be called from the _qemudPipe_closeFromGuest callback with guest_close
+         * set to 1. */
+        char  tmp[128], *p=tmp, *end=p+sizeof(tmp);
+        p = bufprint(tmp, end, "disconnect:00");
+        _qemud_pipe_send(c, (uint8_t*)tmp, p-tmp);
+        return;
+    }
+
     c->closing = 1;
 
     /* remove from current list */
     qemud_client_remove(c);
 
-    /* send a disconnect command to the daemon */
     if (_is_pipe_client(c)) {
-        char  tmp[128], *p=tmp, *end=p+sizeof(tmp);
-        p = bufprint(tmp, end, "disconnect:00");
-        _qemud_pipe_send(c, (uint8_t*)tmp, p-tmp);
         /* We must NULL the client reference in the QemuPipe for this connection,
          * so if a sudden receive request comes after client has been closed, we
          * don't blow up. */
         c->ProtocolSelector.Pipe.qemud_pipe->client = NULL;
     } else if (c->ProtocolSelector.Serial.channel > 0) {
+        /* send a disconnect command to the daemon */
         char  tmp[128], *p=tmp, *end=p+sizeof(tmp);
         p = bufprint(tmp, end, "disconnect:%02x",
                      c->ProtocolSelector.Serial.channel);
@@ -1348,7 +1365,7 @@ qemud_multiplexer_disconnect( QemudMultiplexer*  m,
              * m->clients automatically.
              */
             c->ProtocolSelector.Serial.channel = -1; /* no need to send disconnect:<id> */
-            qemud_client_disconnect(c);
+            qemud_client_disconnect(c, 0);
             return;
         }
     }
@@ -1378,7 +1395,7 @@ qemud_multiplexer_disconnect_noncontrol( QemudMultiplexer*  m )
             D("%s: disconnecting client %d\n",
               __FUNCTION__, c->ProtocolSelector.Serial.channel);
             c->ProtocolSelector.Serial.channel = -1; /* do not send disconnect:<id> */
-            qemud_client_disconnect(c);
+            qemud_client_disconnect(c, 0);
         }
     }
 }
@@ -1695,7 +1712,7 @@ qemud_client_set_framing( QemudClient*  client, int  framing )
 void
 qemud_client_close( QemudClient*  client )
 {
-    qemud_client_disconnect(client);
+    qemud_client_disconnect(client, 0);
 }
 
 
@@ -1945,7 +1962,7 @@ _qemudPipe_closeFromGuest( void* opaque )
     QemudClient*  client = pipe->client;
     D("%s", __FUNCTION__);
     if (client != NULL) {
-        qemud_client_disconnect(client);
+        qemud_client_disconnect(client, 1);
     } else {
         D("%s: Unexpected NULL client", __FUNCTION__);
     }
-- 
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