[PATCH v3 2/6] Cleaned up flow of code in qemu_set_log(), to simplify and clarify.

[Robert Foley <robert.foley@linaro.org>]

Also added some explanation of the reasoning behind the branches.

Signed-off-by: Robert Foley <robert.foley@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
---
v2
    - This is new in patch v2.
---
 util/log.c | 21 +++++++++++++++------
 1 file changed, 15 insertions(+), 6 deletions(-)

diff --git a/util/log.c b/util/log.c
index 4316fe74ee..417d16ec66 100644
--- a/util/log.c
+++ b/util/log.c
@@ -54,12 +54,25 @@ static bool log_uses_own_buffers;
 /* enable or disable low levels log */
 void qemu_set_log(int log_flags)
 {
+    bool need_to_open_file = false;
     qemu_loglevel = log_flags;
 #ifdef CONFIG_TRACE_LOG
     qemu_loglevel |= LOG_TRACE;
 #endif
-    if (!qemu_logfile &&
-        (is_daemonized() ? logfilename != NULL : qemu_loglevel)) {
+    /*
+     * In all cases we only log if qemu_loglevel is set.
+     * Also:
+     *   If not daemonized we will always log either to stderr
+     *     or to a file (if there is a logfilename).
+     *   If we are daemonized,
+     *     we will only log if there is a logfilename.
+     */
+    if (qemu_loglevel && (!is_daemonized() || logfilename)) {
+        need_to_open_file = true;
+    }
+    if (qemu_logfile && !need_to_open_file) {
+        qemu_log_close();
+    } else if (!qemu_logfile && need_to_open_file) {
         if (logfilename) {
             qemu_logfile = fopen(logfilename, log_append ? "a" : "w");
             if (!qemu_logfile) {
@@ -93,10 +106,6 @@ void qemu_set_log(int log_flags)
             log_append = 1;
         }
     }
-    if (qemu_logfile &&
-        (is_daemonized() ? logfilename == NULL : !qemu_loglevel)) {
-        qemu_log_close();
-    }
 }
 
 void qemu_log_needs_buffers(void)
-- 
2.17.1