Check that QEMU is still alive while reading startup output.

By checking the pid every retry period, we can quickly determine if
the process crashed at startup, rather than make the user wait for
the entire timeout (3 seconds).

diff --git a/ChangeLog b/ChangeLog
index d43ea5fd61cfb0ceba4f27a25f5352a6de5aa8ef..3157b92e3e49fd4c85c1798e30b121bdb2ba38a5 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Mon May 11 09:51:00 EDT 2009 Cole Robinson <crobinso@redhat.com>
+
+       * src/qemu_driver.c : Check that QEMU is still alive while
+       reading startup output.
+
 Mon May 11 09:44:40 EDT 2009 Cole Robinson <crobinso@redhat.com>
 
        * src/util.[ch] : Add pidfile argument to __virExec

diff --git a/src/qemu_driver.c b/src/qemu_driver.c
index 61a7cf1d470472e7fe4160b02917c7c3a6cfa990..30642d50092681b1be60275c37ba3963a30aed83 100644 (file)
--- a/src/qemu_driver.c
+++ b/src/qemu_driver.c
@@ -744,29 +744,40 @@ qemudReadLogOutput(virConnectPtr conn,
                    int timeout)
 {
     int retries = timeout*10;
+    int got = 0;
     buf[0] = '\0';
 
     while (retries) {
         ssize_t ret;
-        size_t got = 0;
+        int isdead = 0;
 
-        while((ret = read(fd, buf+got, buflen-got-1)) > 0) {
-            got += ret;
-            buf[got] = '\0';
-            if ((buflen-got-1) == 0) {
-                qemudReportError(conn, NULL, NULL, VIR_ERR_INTERNAL_ERROR,
-                                 _("Out of space while reading %s log output"), what);
-                return -1;
-            }
-        }
+        if (kill(vm->pid, 0) == -1 && errno == ESRCH)
+            isdead = 1;
 
-        if (ret < 0 && errno != EINTR) {
+        ret = saferead(fd, buf+got, buflen-got-1);
+        if (ret < 0) {
             virReportSystemError(conn, errno,
                                  _("Failure while reading %s log output"),
                                  what);
             return -1;
         }
 
+        got += ret;
+        buf[got] = '\0';
+        if (got == buflen-1) {
+            qemudReportError(conn, NULL, NULL, VIR_ERR_INTERNAL_ERROR,
+                             _("Out of space while reading %s log output"),
+                             what);
+            return -1;
+        }
+
+        if (isdead) {
+            qemudReportError(conn, NULL, NULL, VIR_ERR_INTERNAL_ERROR,
+                             _("Process exited while reading %s log output"),
+                             what);
+            return -1;
+        }
+
         ret = func(conn, vm, buf, fd);
         if (ret <= 0)
             return ret;