From dc832ec714a9cf830ccc834e219c054bd24c21e4 Mon Sep 17 00:00:00 2001
From: Simon McVittie <simon.mcvittie@collabora.co.uk>
Date: Mon, 18 Feb 2013 18:21:52 +0000
Subject: [PATCH 4/5] core: if running as user, pick up the X11 display from
 logind

Otherwise, user-bus-activated services that are GUIs, like
gnome-terminal, will not be able to access the appropriate display.

Signed-off-by: Simon McVittie <simon.mcvittie@collabora.co.uk>
---
 src/core/manager.c |   78 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 src/core/manager.h |    8 +++++-
 2 files changed, 85 insertions(+), 1 deletion(-)

diff --git a/src/core/manager.c b/src/core/manager.c
index 28f169d..0727623 100644
--- a/src/core/manager.c
+++ b/src/core/manager.c
@@ -277,6 +277,27 @@ static int manager_setup_signals(Manager *m) {
         return 0;
 }
 
+static int manager_setup_login_monitor(Manager *m) {
+        int r;
+        struct epoll_event ev;
+
+        r = sd_login_monitor_new("uid", &m->login_monitor);
+        if (r < 0)
+                return r;
+        m->login_monitor_watch.type = WATCH_LOGIN_MONITOR;
+        m->login_monitor_watch.fd = sd_login_monitor_get_fd(m->login_monitor);
+
+        zero(ev);
+        ev.events = EPOLLIN;
+        ev.data.ptr = &m->login_monitor_watch;
+
+        if (epoll_ctl(m->epoll_fd, EPOLL_CTL_ADD, m->login_monitor_watch.fd, &ev) < 0)
+                return -errno;
+
+        return 0;
+}
+
+
 static void manager_strip_environment(Manager *m) {
         assert(m);
 
@@ -382,6 +403,12 @@ int manager_new(SystemdRunningAs running_as, Manager **_m) {
 
         m->taint_usr = dir_is_empty("/usr") > 0;
 
+        if (running_as != SYSTEMD_SYSTEM) {
+                r = manager_setup_login_monitor(m);
+                if (r < 0)
+                        goto fail;
+        }
+
         *_m = m;
         return 0;
 
@@ -583,6 +610,8 @@ void manager_free(Manager *m) {
         for (i = 0; i < RLIMIT_NLIMITS; i++)
                 free(m->rlimit[i]);
 
+        sd_login_monitor_unref(m->login_monitor);
+
         free(m);
 }
 
@@ -1417,6 +1446,46 @@ static int manager_process_signal_fd(Manager *m) {
         return 0;
 }
 
+static int manager_process_login_monitor_fd(Manager *m) {
+        int r;
+        int i;
+        char *d = NULL;
+        char *env;
+        char **e;
+
+        assert(m);
+        assert(m->login_monitor);
+
+        sd_login_monitor_flush(m->login_monitor);
+
+        /* Something has changed. Reload our idea of what $DISPLAY should be */
+        r = sd_uid_get_display(getuid(), &d);
+
+        if (r < 0 && r != -ENOENT)
+                return r;
+
+        if (r == -ENOENT || isempty(d)) {
+                free(d);
+                m->environment = strv_env_unset(m->environment, "DISPLAY");
+        } else {
+                r = asprintf(&env, "DISPLAY=%s", d);
+                free(d);
+                if (r < 0)
+                        return -ENOMEM;
+
+                e = strv_env_set(m->environment, env);
+                free(env);
+
+                if (!e)
+                        return -ENOMEM;
+
+                strv_free(m->environment);
+                m->environment = e;
+        }
+
+        return 0;
+}
+
 static int process_event(Manager *m, struct epoll_event *ev) {
         int r;
         Watch *w;
@@ -1525,6 +1594,15 @@ static int process_event(Manager *m, struct epoll_event *ev) {
                 }
 
                 break;
+
+        case WATCH_LOGIN_MONITOR:
+                if (ev->events != EPOLLIN)
+                        return -EINVAL;
+
+                if ((r = manager_process_login_monitor_fd(m)) < 0)
+                        return r;
+
+                break;
         }
 
         default:
diff --git a/src/core/manager.h b/src/core/manager.h
index cc4edf8..8d36561 100644
--- a/src/core/manager.h
+++ b/src/core/manager.h
@@ -27,6 +27,7 @@
 #include <dbus/dbus.h>
 
 #include "fdset.h"
+#include "sd-login.h"
 
 /* Enforce upper limit how many names we allow */
 #define MANAGER_MAX_NAMES 131072 /* 128K */
@@ -61,7 +62,8 @@ enum WatchType {
         WATCH_UDEV,
         WATCH_DBUS_WATCH,
         WATCH_DBUS_TIMEOUT,
-        WATCH_TIME_CHANGE
+        WATCH_TIME_CHANGE,
+        WATCH_LOGIN_MONITOR
 };
 
 struct Watch {
@@ -230,6 +232,10 @@ struct Manager {
 
         char *switch_root;
         char *switch_root_init;
+
+        /* if we are a user manager */
+        sd_login_monitor *login_monitor;
+        Watch login_monitor_watch;
 };
 
 int manager_new(SystemdRunningAs running_as, Manager **m);
-- 
1.7.10.4