[libvirt] [PATCH] util: Fix the default log output to 'journald' when running under systemd

[Erik Skultety]

Essentially, bring back the old behaviour as of commit eba36a38 which
was later changed by commit ae06048bf5d. Even though all the stderr
messages will eventually end up in the journal, we're not making use of
the fields journald provides.

https://bugzilla.redhat.com/show_bug.cgi?id=1592644

Signed-off-by: Erik Skultety <eskultet at redhat.com>
---
 src/util/virlog.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/src/util/virlog.c b/src/util/virlog.c
index cb6901d9bf..3ee58c5db6 100644
--- a/src/util/virlog.c
+++ b/src/util/virlog.c
@@ -223,11 +223,17 @@ virLogSetDefaultOutputToFile(const char *filename, bool privileged)
 int
 virLogSetDefaultOutput(const char *filename, bool godaemon, bool privileged)
 {
-    if (!godaemon)
+    bool have_journald = access("/run/systemd/journal/socket", W_OK) >= 0;
+
+    if (godaemon) {
+        if (have_journald)
+            return virLogSetDefaultOutputToJournald();
+    } else {
+        if (!isatty(STDIN_FILENO) && have_journald)
+            return virLogSetDefaultOutputToJournald();
+
         return virLogSetDefaultOutputToStderr();
-
-    if (access("/run/systemd/journal/socket", W_OK) >= 0)
-        return virLogSetDefaultOutputToJournald();
+    }
 
     return virLogSetDefaultOutputToFile(filename, privileged);
 }
-- 
2.20.1