[libvirt] [PATCH] Speed up fallback to legacy non-QMP probing

[Daniel P. Berrange]

From: "Daniel P. Berrange" <berrange at redhat.com>

Since we daemonized QEMU for capabilities probing there is a long
time if QEMU fals to launch. This is because we're not passing in
any virDomainObjPtr instance and thus the monitor code can not
check to see if the PID is still alive.

Signed-off-by: Daniel P. Berrange <berrange at redhat.com>
---
 src/qemu/qemu_capabilities.c | 34 ++++++++++++++++++++--------------
 1 file changed, 20 insertions(+), 14 deletions(-)

diff --git a/src/qemu/qemu_capabilities.c b/src/qemu/qemu_capabilities.c
index e16bc70..bcecc6d 100644
--- a/src/qemu/qemu_capabilities.c
+++ b/src/qemu/qemu_capabilities.c
@@ -2307,6 +2307,8 @@ qemuCapsInitQMP(qemuCapsPtr caps,
     char *pidfile = NULL;
     qemuCapsHookData hookData;
     char *archstr;
+    pid_t pid = 0;
+    virDomainObj vm;
 
     /* the ".sock" sufix is important to avoid a possible clash with a qemu
      * domain called "capabilities"
@@ -2360,7 +2362,16 @@ qemuCapsInitQMP(qemuCapsPtr caps,
         goto cleanup;
     }
 
-    if (!(mon = qemuMonitorOpen(NULL, &config, true, &callbacks))) {
+    if (virPidFileReadPath(pidfile, &pid) < 0) {
+        VIR_DEBUG("Failed to read pidfile %s", pidfile);
+        ret = 0;
+        goto cleanup;
+    }
+
+    memset(&vm, 0, sizeof(vm));
+    vm.pid = pid;
+
+    if (!(mon = qemuMonitorOpen(&vm, &config, true, &callbacks))) {
         ret = 0;
         goto cleanup;
     }
@@ -2446,21 +2457,16 @@ cleanup:
     VIR_FREE(monpath);
     VIR_FREE(package);
 
-    if (pidfile) {
+    if (pid != 0) {
         char ebuf[1024];
-        pid_t pid;
-        int rc;
 
-        if ((rc = virPidFileReadPath(pidfile, &pid)) < 0) {
-            VIR_DEBUG("Failed to read pidfile %s: %s",
-                      pidfile, virStrerror(-rc, ebuf, sizeof(ebuf)));
-        } else {
-            VIR_DEBUG("Killing QMP caps process %lld", (long long) pid);
-            if (virProcessKill(pid, SIGKILL) < 0 && errno != ESRCH)
-                VIR_ERROR(_("Failed to kill process %lld: %s"),
-                          (long long) pid,
-                          virStrerror(errno, ebuf, sizeof(ebuf)));
-        }
+        VIR_DEBUG("Killing QMP caps process %lld", (long long) pid);
+        if (virProcessKill(pid, SIGKILL) < 0 && errno != ESRCH)
+            VIR_ERROR(_("Failed to kill process %lld: %s"),
+                      (long long) pid,
+                      virStrerror(errno, ebuf, sizeof(ebuf)));
+    }
+    if (pidfile) {
         unlink(pidfile);
         VIR_FREE(pidfile);
     }
-- 
1.8.0.1