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authorDavid Herrmann <dh.herrmann@gmail.com>2014-12-16 17:30:46 +0100
committerDavid Herrmann <dh.herrmann@gmail.com>2015-03-11 12:32:48 +0100
commitb2068772f5fd05173c4a42a907e42bb69160170c (patch)
treee71199609e655d5e498f92fab760bed6f509dcc0
parent84c3561c58dd992b339afe5bb4c41971a2ebc486 (diff)
terminal/sysview: introduce SETTLE events
This introduces a new SYSVIEW_EVENT_SETTLE notification that is sent after initial scanning via sysview is done. This is very handy to let the application raise warnings in case requested resources are not found during startup. The SETTLE event is sent after systemd-logind and udev enumerations are done. This event does in no way guarantee that a given resource is available. All it does is notify the application that scanning is done! You must not react to SETTLE if you don't have external synchronization with the resource you're waiting for. The main use-case for SETTLE is to run applications _inside_ of logind sessions and startup sysview. You really want to make sure that the own session you're running in was found during enumeration. If not, something is seriously wrong.
-rw-r--r--src/libsystemd-terminal/sysview-internal.h2
-rw-r--r--src/libsystemd-terminal/sysview.c66
-rw-r--r--src/libsystemd-terminal/sysview.h2
3 files changed, 62 insertions, 8 deletions
diff --git a/src/libsystemd-terminal/sysview-internal.h b/src/libsystemd-terminal/sysview-internal.h
index 39ff933eaa..f1fd4b5f53 100644
--- a/src/libsystemd-terminal/sysview-internal.h
+++ b/src/libsystemd-terminal/sysview-internal.h
@@ -113,6 +113,7 @@ struct sysview_context {
sd_bus *sysbus;
struct udev *ud;
uint64_t custom_sid;
+ unsigned int n_probe;
Hashmap *seat_map;
Hashmap *session_map;
@@ -137,6 +138,7 @@ struct sysview_context {
bool running : 1;
bool scanned : 1;
bool rescan : 1;
+ bool settled : 1;
};
int sysview_context_rescan(sysview_context *c);
diff --git a/src/libsystemd-terminal/sysview.c b/src/libsystemd-terminal/sysview.c
index cd61ea44e7..550f0305af 100644
--- a/src/libsystemd-terminal/sysview.c
+++ b/src/libsystemd-terminal/sysview.c
@@ -474,6 +474,14 @@ static int context_raise(sysview_context *c, sysview_event *event, int def) {
return c->running ? c->event_fn(c, c->userdata, event) : def;
}
+static int context_raise_settle(sysview_context *c) {
+ sysview_event event = {
+ .type = SYSVIEW_EVENT_SETTLE,
+ };
+
+ return context_raise(c, &event, 0);
+}
+
static int context_raise_seat_add(sysview_context *c, sysview_seat *seat) {
sysview_event event = {
.type = SYSVIEW_EVENT_SEAT_ADD,
@@ -585,6 +593,21 @@ static int context_raise_session_refresh(sysview_context *c, sysview_session *se
return context_raise(c, &event, 0);
}
+static void context_settle(sysview_context *c) {
+ int r;
+
+ if (c->n_probe <= 0 || --c->n_probe > 0)
+ return;
+
+ log_debug("sysview: settle");
+
+ c->settled = true;
+
+ r = context_raise_settle(c);
+ if (r < 0)
+ log_debug_errno(r, "sysview: callback failed on settle: %m");
+}
+
static void context_add_device(sysview_context *c, sysview_device *device) {
sysview_session *session;
Iterator i;
@@ -1251,7 +1274,8 @@ static int context_ld_list_seats_fn(sd_bus *bus,
log_debug("sysview: ListSeats on logind failed: %s: %s",
error->name, error->message);
- return -sd_bus_error_get_errno(error);
+ r = -sd_bus_error_get_errno(error);
+ goto settle;
}
r = sd_bus_message_enter_container(reply, 'a', "(so)");
@@ -1277,12 +1301,16 @@ static int context_ld_list_seats_fn(sd_bus *bus,
r = sd_bus_message_exit_container(reply);
if (r < 0)
- return r;
+ goto error;
- return 0;
+ r = 0;
+ goto settle;
error:
- return log_debug_errno(r, "sysview: erroneous ListSeats response from logind: %m");
+ log_debug_errno(r, "sysview: erroneous ListSeats response from logind: %m");
+settle:
+ context_settle(c);
+ return r;
}
static int context_ld_list_sessions_fn(sd_bus *bus,
@@ -1299,7 +1327,8 @@ static int context_ld_list_sessions_fn(sd_bus *bus,
log_debug("sysview: ListSessions on logind failed: %s: %s",
error->name, error->message);
- return -sd_bus_error_get_errno(error);
+ r = -sd_bus_error_get_errno(error);
+ goto settle;
}
r = sd_bus_message_enter_container(reply, 'a', "(susso)");
@@ -1341,12 +1370,16 @@ static int context_ld_list_sessions_fn(sd_bus *bus,
r = sd_bus_message_exit_container(reply);
if (r < 0)
- return r;
+ goto error;
- return 0;
+ r = 0;
+ goto settle;
error:
- return log_debug_errno(r, "sysview: erroneous ListSessions response from logind: %m");
+ log_debug_errno(r, "sysview: erroneous ListSessions response from logind: %m");
+settle:
+ context_settle(c);
+ return r;
}
static int context_ld_scan(sysview_context *c) {
@@ -1376,6 +1409,9 @@ static int context_ld_scan(sysview_context *c) {
if (r < 0)
return r;
+ if (!c->settled)
+ ++c->n_probe;
+
/* request session list */
m = sd_bus_message_unref(m);
@@ -1397,6 +1433,9 @@ static int context_ld_scan(sysview_context *c) {
if (r < 0)
return r;
+ if (!c->settled)
+ ++c->n_probe;
+
return 0;
}
@@ -1461,6 +1500,8 @@ void sysview_context_stop(sysview_context *c) {
c->running = false;
c->scanned = false;
+ c->settled = false;
+ c->n_probe = 0;
c->event_fn = NULL;
c->userdata = NULL;
c->scan_src = sd_event_source_unref(c->scan_src);
@@ -1474,6 +1515,8 @@ static int context_scan_fn(sd_event_source *s, void *userdata) {
Iterator i;
int r;
+ c->rescan = false;
+
if (!c->scanned) {
r = context_ld_scan(c);
if (r < 0)
@@ -1491,6 +1534,7 @@ static int context_scan_fn(sd_event_source *s, void *userdata) {
}
c->scanned = true;
+ context_settle(c);
return 0;
}
@@ -1501,6 +1545,12 @@ int sysview_context_rescan(sysview_context *c) {
if (!c->running)
return 0;
+ if (!c->rescan) {
+ c->rescan = true;
+ if (!c->settled)
+ ++c->n_probe;
+ }
+
if (c->scan_src)
return sd_event_source_set_enabled(c->scan_src, SD_EVENT_ONESHOT);
else
diff --git a/src/libsystemd-terminal/sysview.h b/src/libsystemd-terminal/sysview.h
index aa5527ff32..71e56e7ebf 100644
--- a/src/libsystemd-terminal/sysview.h
+++ b/src/libsystemd-terminal/sysview.h
@@ -51,6 +51,8 @@ typedef struct sysview_context sysview_context;
*/
enum {
+ SYSVIEW_EVENT_SETTLE,
+
SYSVIEW_EVENT_SEAT_ADD,
SYSVIEW_EVENT_SEAT_REMOVE,