journal: Don't use loginuid if it's not valid

Code above this attempted to load loginuid, if this failed for
whatever reason, we'd still end up using that value (0) in place of
realuid.  Fix this by setting a bool when we know the loginuid is
valid.

This fixes journal messages showing up in per-user journals in
gnome-ostree (not configured with loginuid, but I'll shortly fix
that).

1 files changed, 13 insertions, 5 deletions

diff --git a/src/journal/journald-server.c b/src/journal/journald-server.c
index 12a46e6bd0..1375d7a98e 100644
--- a/src/journal/journald-server.c
+++ b/src/journal/journald-server.c
@@ -515,6 +515,8 @@ static void dispatch_message_real(
         int r;
         char *t;
         uid_t loginuid = 0, realuid = 0;
+        uid_t journal_uid;
+        bool loginuid_valid = false;
 
         assert(s);
         assert(iovec);
@@ -571,9 +573,11 @@ static void dispatch_message_real(
                                 IOVEC_SET_STRING(iovec[n++], audit_session);
 
                 r = audit_loginuid_from_pid(ucred->pid, &loginuid);
-                if (r >= 0)
+                if (r >= 0) {
+                        loginuid_valid = true;
                         if (asprintf(&audit_loginuid, "_AUDIT_LOGINUID=%lu", (unsigned long) loginuid) >= 0)
                                 IOVEC_SET_STRING(iovec[n++], audit_loginuid);
+                }
 
                 t = shortened_cgroup_path(ucred->pid);
                 if (t) {
@@ -666,10 +670,14 @@ static void dispatch_message_real(
 
         assert(n <= m);
 
-        write_to_journal(s,
-                         s->split_mode == SPLIT_NONE ? 0 :
-                         (s->split_mode == SPLIT_UID ? realuid :
-                          (realuid == 0 ? 0 : loginuid)), iovec, n);
+        if (s->split_mode == SPLIT_NONE)
+                journal_uid = 0;
+        else if (s->split_mode == SPLIT_UID || realuid == 0 || !loginuid_valid)
+                journal_uid = realuid;
+        else
+                journal_uid = loginuid;
+
+        write_to_journal(s, journal_uid, iovec, n);
 }
 
 void server_driver_message(Server *s, sd_id128_t message_id, const char *format, ...) {