[PATCH 2/2] util/log: add timestamp to logs via qemu_log()

[Dongli Zhang]

The qemu_log is very helpful for diagnostic. Add the timestamp to the log
when it is enabled (e.g., "-msg timestamp=on").

While there are many other places that may print to log file, this patch is
only for qemu_log(), e.g., the developer may add qemu_log/qemu_log_mask to
selected locations to diagnose QEMU issue.

Cc: Joe Jin <joe.jin@oracle.com>
Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com>
---
Please let me know if we should use 'error_with_guestname' as well.

 util/log.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/util/log.c b/util/log.c
index d6eb037..f0a081a 100644
--- a/util/log.c
+++ b/util/log.c
@@ -129,8 +129,15 @@ void qemu_log(const char *fmt, ...)
 {
     FILE *f = qemu_log_trylock();
     if (f) {
+        gchar *timestr;
         va_list ap;
 
+        if (message_with_timestamp) {
+            timestr = real_time_iso8601();
+            fprintf(f, "%s ", timestr);
+            g_free(timestr);
+        }
+
         va_start(ap, fmt);
         vfprintf(f, fmt, ap);
         va_end(ap);
-- 
1.8.3.1