journald: add support for wall forwarding

This will let journald forward logs as messages sent to all logged in
users (like wall).

Two options are added:
 * ForwardToWall (default yes)
 * MaxLevelWall (default emerg)
'ForwardToWall' is overridable by kernel command line option
'systemd.journald.forward_to_wall'.

This is used to emulate the traditional syslogd behaviour of sending
emergency messages to all logged in users.

1 files changed, 69 insertions, 0 deletions

diff --git a/src/journal/journald-wall.c b/src/journal/journald-wall.c
new file mode 100644
index 0000000000..fcbd9183fe
--- /dev/null
+++ b/src/journal/journald-wall.c
@@ -0,0 +1,69 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+  This file is part of systemd.
+
+  Copyright 2014 Sebastian Thorarensen
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 of the License, or
+  (at your option) any later version.
+
+  systemd is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include "utmp-wtmp.h"
+#include "journald-server.h"
+#include "journald-wall.h"
+
+void server_forward_wall(
+                Server *s,
+                int priority,
+                const char *identifier,
+                const char *message,
+                struct ucred *ucred) {
+
+        _cleanup_free_ char *ident_buf = NULL, *l_buf = NULL;
+        const char *l;
+        int r;
+
+        assert(s);
+        assert(message);
+
+        if (LOG_PRI(priority) > s->max_level_wall)
+                return;
+
+        if (ucred) {
+                if (!identifier) {
+                        get_process_comm(ucred->pid, &ident_buf);
+                        identifier = ident_buf;
+                }
+
+                if (asprintf(&l_buf, "%s["PID_FMT"]: %s", strempty(identifier), ucred->pid, message) < 0) {
+                        log_oom();
+                        return;
+                }
+
+                l = l_buf;
+
+        } else if (identifier) {
+
+                l = l_buf = strjoin(identifier, ": ", message, NULL);
+                if (!l_buf) {
+                        log_oom();
+                        return;
+                }
+        } else
+                l = message;
+
+        r = utmp_wall(l, "systemd-journald", NULL);
+        if (r < 0)
+                log_debug("Failed to send wall message: %s", strerror(-r));
+}