qemu: agent: Differentiate timeouts when syncing from command timeout

As the guest agent code uses timeouts it is possible that we stop
waiting before the guest agent replies. If this happens while syncing
everything is okay because we didn't send any state-changing command.

In case when the timeout happens after a real command was transmitted
it's unknown if the guest-agent processed it or not.

Use the new special error code VIR_ERR_AGENT_COMMAND_TIMEOUT for cases
when we sent non-sync commands, so that the management applications or
users have possibility to react to this situation.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>

diff --git a/src/qemu/qemu_agent.c b/src/qemu/qemu_agent.c
index 6f5aab5bf24abd40e66ce8e6c64cf721de432f55..879c3a8f4198fcd5e3e73465ec7a898532de9ad7 100644 (file)
--- a/src/qemu/qemu_agent.c
+++ b/src/qemu/qemu_agent.c
@@ -707,6 +707,7 @@ void qemuAgentClose(qemuAgent *agent)
  * @msg: Message
  * @seconds: number of seconds to wait for the result, it can be either
  *           -2, -1, 0 or positive.
+ * @report_sync: On timeout; report synchronization error instead of the normal error
  *
  * Send @msg to agent @agent. If @seconds is equal to
  * VIR_DOMAIN_QEMU_AGENT_COMMAND_BLOCK(-2), this function will block forever
@@ -720,9 +721,11 @@ void qemuAgentClose(qemuAgent *agent)
  *          -2 on timeout,
  *          -1 otherwise
  */
-static int qemuAgentSend(qemuAgent *agent,
-                         qemuAgentMessage *msg,
-                         int seconds)
+static int
+qemuAgentSend(qemuAgent *agent,
+              qemuAgentMessage *msg,
+              int seconds,
+              bool report_sync)
 {
     int ret = -1;
     unsigned long long then = 0;
@@ -751,8 +754,15 @@ static int qemuAgentSend(qemuAgent *agent,
         if ((then && virCondWaitUntil(&agent->notify, &agent->parent.lock, then) < 0) ||
             (!then && virCondWait(&agent->notify, &agent->parent.lock) < 0)) {
             if (errno == ETIMEDOUT) {
-                virReportError(VIR_ERR_AGENT_UNRESPONSIVE, "%s",
-                               _("Guest agent not available for now"));
+                if (report_sync) {
+                    virReportError(VIR_ERR_AGENT_UNRESPONSIVE,
+                                   _("guest agent didn't respond to synchronization within '%1$d' seconds"),
+                                   seconds);
+                } else {
+                    virReportError(VIR_ERR_AGENT_COMMAND_TIMEOUT,
+                                   _("guest agent didn't respond to command within '%1$d' seconds"),
+                                   seconds);
+                }
                 ret = -2;
             } else {
                 virReportSystemError(errno, "%s",
@@ -817,7 +827,7 @@ qemuAgentGuestSyncSend(qemuAgent *agent,
 
     VIR_DEBUG("Sending guest-sync command with ID: %llu", id);
 
-    rc = qemuAgentSend(agent, &sync_msg, timeout);
+    rc = qemuAgentSend(agent, &sync_msg, timeout, true);
     rxObj = g_steal_pointer(&sync_msg.rxObject);
 
     VIR_DEBUG("qemuAgentSend returned: %d", rc);
@@ -1040,7 +1050,7 @@ qemuAgentCommandFull(qemuAgent *agent,
 
     VIR_DEBUG("Send command '%s' for write, seconds = %d", cmdstr, seconds);
 
-    ret = qemuAgentSend(agent, &msg, seconds);
+    ret = qemuAgentSend(agent, &msg, seconds, false);
 
     VIR_DEBUG("Receive command reply ret=%d rxObject=%p",
               ret, msg.rxObject);