Re: [systemd-devel] [PATCH v2 01/10] logind: listen actively for session devices
On Tue, 17.09.13 17:39, David Herrmann (dh.herrm...@gmail.com) wrote:
Applied! Thanks!
Session compositors need access to fbdev, DRM and evdev devices if they
control a session. To make logind pass them to sessions, we need to
listen for them actively.
However, we avoid creating new seats for non master-of-seat devices. Only
once a seat is created, we start remembering all other session devices. If
the last master-device is removed (even if there are other non-master
devices still available), we destroy the seat. This is the current
behavior, but we need to explicitly implement it now as there may be
non-master devices in the seat-devices list.
Unlike master devices, we don't care whether our list of non-master
devices is complete. We don't export this list but use it only as cache if
sessions request these devices. Hence, if a session requests a device that
is not in the list, we will simply look it up. However, once a session
requested a device, we must be notified of remove udev events. So we
must link the devices somehow into the device-list.
Regarding the implementation, we now sort the device list by the master
flag. This guarantees that master devices are at the front and non-master
devices at the tail of the list. Thus, we can easily test whether a seat
has a master device attached.
---
src/login/logind-device.c | 35 ++---
src/login/logind-device.h | 3 +-
src/login/logind-seat.c | 11 +--
src/login/logind-seat.h | 1 +
src/login/logind.c| 79
+--
src/login/logind.h| 6 ++--
6 files changed, 116 insertions(+), 19 deletions(-)
diff --git a/src/login/logind-device.c b/src/login/logind-device.c
index 51b1535..a9a9633 100644
--- a/src/login/logind-device.c
+++ b/src/login/logind-device.c
@@ -25,7 +25,7 @@
#include logind-device.h
#include util.h
-Device* device_new(Manager *m, const char *sysfs) {
+Device* device_new(Manager *m, const char *sysfs, bool master) {
Device *d;
assert(m);
@@ -48,6 +48,7 @@ Device* device_new(Manager *m, const char *sysfs) {
}
d-manager = m;
+d-master = master;
dual_timestamp_get(d-timestamp);
return d;
@@ -75,11 +76,16 @@ void device_detach(Device *d) {
LIST_REMOVE(Device, devices, d-seat-devices, d);
d-seat = NULL;
-seat_add_to_gc_queue(s);
-seat_send_changed(s, CanGraphical\0);
+if (!seat_has_master_device(s)) {
+seat_add_to_gc_queue(s);
+seat_send_changed(s, CanGraphical\0);
+}
}
void device_attach(Device *d, Seat *s) {
+Device *i;
+bool had_master;
+
assert(d);
assert(s);
@@ -90,7 +96,26 @@ void device_attach(Device *d, Seat *s) {
device_detach(d);
d-seat = s;
-LIST_PREPEND(Device, devices, s-devices, d);
+had_master = seat_has_master_device(s);
+
+/* We keep the device list sorted by the master flag. That is,
master
+ * devices are at the front, other devices at the tail. As there is
no
+ * way to easily add devices at the list-tail, we need to iterate the
+ * list to find the first non-master device when adding non-master
+ * devices. We assume there is only a few (normally 1) master devices
+ * per seat, so we iterate only a few times. */
+
+if (d-master || !s-devices) {
+LIST_PREPEND(Device, devices, s-devices, d);
+} else {
+LIST_FOREACH(devices, i, s-devices) {
+if (!i-devices_next || !i-master) {
+LIST_INSERT_AFTER(Device, devices,
s-devices, i, d);
+break;
+}
+}
+}
-seat_send_changed(s, CanGraphical\0);
+if (!had_master d-master)
+seat_send_changed(s, CanGraphical\0);
}
diff --git a/src/login/logind-device.h b/src/login/logind-device.h
index 3b15356..315f0e6 100644
--- a/src/login/logind-device.h
+++ b/src/login/logind-device.h
@@ -33,13 +33,14 @@ struct Device {
char *sysfs;
Seat *seat;
+bool master;
dual_timestamp timestamp;
LIST_FIELDS(struct Device, devices);
};
-Device* device_new(Manager *m, const char *sysfs);
+Device* device_new(Manager *m, const char *sysfs, bool master);
void device_free(Device *d);
void device_attach(Device *d, Seat *s);
void device_detach(Device *d);
diff --git a/src/login/logind-seat.c b/src/login/logind-seat.c
index 470d08b..2c60b8a 100644
--- a/src/login/logind-seat.c
+++ b/src/login/logind-seat.c
@@ -448,10 +448,17 @@ bool seat_can_tty(Seat *s) {
return seat_is_vtconsole(s);
}
+bool seat_has_master_device(Seat *s) {
+assert(s);
[systemd-devel] [PATCH v2 01/10] logind: listen actively for session devices
Session compositors need access to fbdev, DRM and evdev devices if they
control a session. To make logind pass them to sessions, we need to
listen for them actively.
However, we avoid creating new seats for non master-of-seat devices. Only
once a seat is created, we start remembering all other session devices. If
the last master-device is removed (even if there are other non-master
devices still available), we destroy the seat. This is the current
behavior, but we need to explicitly implement it now as there may be
non-master devices in the seat-devices list.
Unlike master devices, we don't care whether our list of non-master
devices is complete. We don't export this list but use it only as cache if
sessions request these devices. Hence, if a session requests a device that
is not in the list, we will simply look it up. However, once a session
requested a device, we must be notified of remove udev events. So we
must link the devices somehow into the device-list.
Regarding the implementation, we now sort the device list by the master
flag. This guarantees that master devices are at the front and non-master
devices at the tail of the list. Thus, we can easily test whether a seat
has a master device attached.
---
src/login/logind-device.c | 35 ++---
src/login/logind-device.h | 3 +-
src/login/logind-seat.c | 11 +--
src/login/logind-seat.h | 1 +
src/login/logind.c| 79 +--
src/login/logind.h| 6 ++--
6 files changed, 116 insertions(+), 19 deletions(-)
diff --git a/src/login/logind-device.c b/src/login/logind-device.c
index 51b1535..a9a9633 100644
--- a/src/login/logind-device.c
+++ b/src/login/logind-device.c
@@ -25,7 +25,7 @@
#include logind-device.h
#include util.h
-Device* device_new(Manager *m, const char *sysfs) {
+Device* device_new(Manager *m, const char *sysfs, bool master) {
Device *d;
assert(m);
@@ -48,6 +48,7 @@ Device* device_new(Manager *m, const char *sysfs) {
}
d-manager = m;
+d-master = master;
dual_timestamp_get(d-timestamp);
return d;
@@ -75,11 +76,16 @@ void device_detach(Device *d) {
LIST_REMOVE(Device, devices, d-seat-devices, d);
d-seat = NULL;
-seat_add_to_gc_queue(s);
-seat_send_changed(s, CanGraphical\0);
+if (!seat_has_master_device(s)) {
+seat_add_to_gc_queue(s);
+seat_send_changed(s, CanGraphical\0);
+}
}
void device_attach(Device *d, Seat *s) {
+Device *i;
+bool had_master;
+
assert(d);
assert(s);
@@ -90,7 +96,26 @@ void device_attach(Device *d, Seat *s) {
device_detach(d);
d-seat = s;
-LIST_PREPEND(Device, devices, s-devices, d);
+had_master = seat_has_master_device(s);
+
+/* We keep the device list sorted by the master flag. That is, master
+ * devices are at the front, other devices at the tail. As there is no
+ * way to easily add devices at the list-tail, we need to iterate the
+ * list to find the first non-master device when adding non-master
+ * devices. We assume there is only a few (normally 1) master devices
+ * per seat, so we iterate only a few times. */
+
+if (d-master || !s-devices) {
+LIST_PREPEND(Device, devices, s-devices, d);
+} else {
+LIST_FOREACH(devices, i, s-devices) {
+if (!i-devices_next || !i-master) {
+LIST_INSERT_AFTER(Device, devices, s-devices,
i, d);
+break;
+}
+}
+}
-seat_send_changed(s, CanGraphical\0);
+if (!had_master d-master)
+seat_send_changed(s, CanGraphical\0);
}
diff --git a/src/login/logind-device.h b/src/login/logind-device.h
index 3b15356..315f0e6 100644
--- a/src/login/logind-device.h
+++ b/src/login/logind-device.h
@@ -33,13 +33,14 @@ struct Device {
char *sysfs;
Seat *seat;
+bool master;
dual_timestamp timestamp;
LIST_FIELDS(struct Device, devices);
};
-Device* device_new(Manager *m, const char *sysfs);
+Device* device_new(Manager *m, const char *sysfs, bool master);
void device_free(Device *d);
void device_attach(Device *d, Seat *s);
void device_detach(Device *d);
diff --git a/src/login/logind-seat.c b/src/login/logind-seat.c
index 470d08b..2c60b8a 100644
--- a/src/login/logind-seat.c
+++ b/src/login/logind-seat.c
@@ -448,10 +448,17 @@ bool seat_can_tty(Seat *s) {
return seat_is_vtconsole(s);
}
+bool seat_has_master_device(Seat *s) {
+assert(s);
+
+/* device list is ordered by master flag */
+return !!s-devices s-devices-master;
+}
+
bool seat_can_graphical(Seat *s) {
assert(s);
-return !!s-devices;
+return
