[systemd-devel] [PATCH v2 09/10] logind: extract has_vts() from can_multi_session()

2013-09-17 Thread David Herrmann 
We currently use seat_can_multi_session() to test for two things:
 * whether the seat can handle session-switching
 * whether the seat has VTs

As both are currently logically equivalent, we didn't care. However, we
want to allow session-switching on seats without VTs, so split this helper
into:
 * seat_can_multi_session(): whether session-switching is supported
 * seat_has_vts(): whether the seat has VTs

Note that only one seat on a system can have VTs. There is only one set of
them. We automatically assign them to seat0 as usual.

With this patch in place, we can easily add new session-switching/tracking
methods without breaking any VT code as it is now protected by has_vts(),
no longer by can_multi_session().
---
 src/login/logind-dbus.c|  2 +-
 src/login/logind-seat.c| 32 ++--
 src/login/logind-seat.h|  1 +
 src/login/logind-session.c |  6 +++---
 4 files changed, 19 insertions(+), 22 deletions(-)

diff --git a/src/login/logind-dbus.c b/src/login/logind-dbus.c
index 4a23c93..fd8ee1b 100644
--- a/src/login/logind-dbus.c
+++ b/src/login/logind-dbus.c
@@ -429,7 +429,7 @@ static int bus_manager_create_session(Manager *m, 
DBusMessage *message) {
 }
 
 if (seat) {
-if (seat_can_multi_session(seat)) {
+if (seat_has_vts(seat)) {
 if (vtnr  63)
 return -EINVAL;
 } else {
diff --git a/src/login/logind-seat.c b/src/login/logind-seat.c
index 4c2c424..f88738a 100644
--- a/src/login/logind-seat.c
+++ b/src/login/logind-seat.c
@@ -201,7 +201,7 @@ int seat_preallocate_vts(Seat *s) {
 if (s-manager-n_autovts = 0)
 return 0;
 
-if (!seat_can_multi_session(s))
+if (!seat_has_vts(s))
 return 0;
 
 for (i = 1; i = s-manager-n_autovts; i++) {
@@ -282,7 +282,7 @@ int seat_active_vt_changed(Seat *s, int vtnr) {
 assert(s);
 assert(vtnr = 1);
 
-if (!seat_can_multi_session(s))
+if (!seat_has_vts(s))
 return -EINVAL;
 
 log_debug(VT changed to %i, vtnr);
@@ -306,7 +306,7 @@ int seat_read_active_vt(Seat *s) {
 
 assert(s);
 
-if (!seat_can_multi_session(s))
+if (!seat_has_vts(s))
 return 0;
 
 lseek(s-manager-console_active_fd, SEEK_SET, 0);
@@ -417,18 +417,20 @@ int seat_attach_session(Seat *s, Session *session) {
 
 seat_send_changed(s, Sessions\0);
 
-/* Note that even if a seat is not multi-session capable it
- * still might have multiple sessions on it since old, dead
- * sessions might continue to be tracked until all their
- * processes are gone. The most recently added session
- * (i.e. the first in s-sessions) is the one that matters. */
-
-if (!seat_can_multi_session(s))
+/* On seats with VTs, the VT logic defines which session is active. On
+ * seats without VTs, we automatically activate the first session. */
+if (!seat_has_vts(s)  !s-active)
 seat_set_active(s, session);
 
 return 0;
 }
 
+bool seat_has_vts(Seat *s) {
+assert(s);
+
+return seat_is_seat0(s)  s-manager-console_active_fd = 0;
+}
+
 bool seat_is_seat0(Seat *s) {
 assert(s);
 
@@ -438,19 +440,13 @@ bool seat_is_seat0(Seat *s) {
 bool seat_can_multi_session(Seat *s) {
 assert(s);
 
-if (!seat_is_seat0(s))
-return false;
-
-/* If we can't watch which VT is in the foreground, we don't
- * support VT switching */
-
-return s-manager-console_active_fd = 0;
+return seat_has_vts(s);
 }
 
 bool seat_can_tty(Seat *s) {
 assert(s);
 
-return seat_is_seat0(s)  s-manager-console_active_fd = 0;
+return seat_has_vts(s);
 }
 
 bool seat_has_master_device(Seat *s) {
diff --git a/src/login/logind-seat.h b/src/login/logind-seat.h
index 47fe89a..d3438b8 100644
--- a/src/login/logind-seat.h
+++ b/src/login/logind-seat.h
@@ -60,6 +60,7 @@ int seat_preallocate_vts(Seat *s);
 
 int seat_attach_session(Seat *s, Session *session);
 
+bool seat_has_vts(Seat *s);
 bool seat_is_seat0(Seat *s);
 bool seat_can_multi_session(Seat *s);
 bool seat_can_tty(Seat *s);
diff --git a/src/login/logind-session.c b/src/login/logind-session.c
index 1df2a06..906115a 100644
--- a/src/login/logind-session.c
+++ b/src/login/logind-session.c
@@ -206,7 +206,7 @@ int session_save(Session *s) {
 if (s-service)
 fprintf(f, SERVICE=%s\n, s-service);
 
-if (s-seat  seat_can_multi_session(s-seat))
+if (s-seat  seat_has_vts(s-seat))
 fprintf(f, VTNR=%i\n, s-vtnr);
 
 if (s-leader  0)
@@ -316,7 +316,7 @@ int session_load(Session *s) {
 seat_attach_session(o, s);
 }
 
-if (vtnr  s-seat  seat_can_multi_session(s-seat)) {
+if (vtnr  s-seat  seat_has_vts(s-seat)) {

Re: [systemd-devel] [PATCH v2 09/10] logind: extract has_vts() from can_multi_session()

2013-09-17 Thread Lennart Poettering 
On Tue, 17.09.13 17:40, David Herrmann (dh.herrm...@gmail.com) wrote:

Applied #6 to #9, please update/rebase #5 and #10.

Thanks a lot!

 We currently use seat_can_multi_session() to test for two things:
  * whether the seat can handle session-switching
  * whether the seat has VTs
 
 As both are currently logically equivalent, we didn't care. However, we
 want to allow session-switching on seats without VTs, so split this helper
 into:
  * seat_can_multi_session(): whether session-switching is supported
  * seat_has_vts(): whether the seat has VTs
 
 Note that only one seat on a system can have VTs. There is only one set of
 them. We automatically assign them to seat0 as usual.
 
 With this patch in place, we can easily add new session-switching/tracking
 methods without breaking any VT code as it is now protected by has_vts(),
 no longer by can_multi_session().
 ---
  src/login/logind-dbus.c|  2 +-
  src/login/logind-seat.c| 32 ++--
  src/login/logind-seat.h|  1 +
  src/login/logind-session.c |  6 +++---
  4 files changed, 19 insertions(+), 22 deletions(-)
 
 diff --git a/src/login/logind-dbus.c b/src/login/logind-dbus.c
 index 4a23c93..fd8ee1b 100644
 --- a/src/login/logind-dbus.c
 +++ b/src/login/logind-dbus.c
 @@ -429,7 +429,7 @@ static int bus_manager_create_session(Manager *m, 
 DBusMessage *message) {
  }
  
  if (seat) {
 -if (seat_can_multi_session(seat)) {
 +if (seat_has_vts(seat)) {
  if (vtnr  63)
  return -EINVAL;
  } else {
 diff --git a/src/login/logind-seat.c b/src/login/logind-seat.c
 index 4c2c424..f88738a 100644
 --- a/src/login/logind-seat.c
 +++ b/src/login/logind-seat.c
 @@ -201,7 +201,7 @@ int seat_preallocate_vts(Seat *s) {
  if (s-manager-n_autovts = 0)
  return 0;
  
 -if (!seat_can_multi_session(s))
 +if (!seat_has_vts(s))
  return 0;
  
  for (i = 1; i = s-manager-n_autovts; i++) {
 @@ -282,7 +282,7 @@ int seat_active_vt_changed(Seat *s, int vtnr) {
  assert(s);
  assert(vtnr = 1);
  
 -if (!seat_can_multi_session(s))
 +if (!seat_has_vts(s))
  return -EINVAL;
  
  log_debug(VT changed to %i, vtnr);
 @@ -306,7 +306,7 @@ int seat_read_active_vt(Seat *s) {
  
  assert(s);
  
 -if (!seat_can_multi_session(s))
 +if (!seat_has_vts(s))
  return 0;
  
  lseek(s-manager-console_active_fd, SEEK_SET, 0);
 @@ -417,18 +417,20 @@ int seat_attach_session(Seat *s, Session *session) {
  
  seat_send_changed(s, Sessions\0);
  
 -/* Note that even if a seat is not multi-session capable it
 - * still might have multiple sessions on it since old, dead
 - * sessions might continue to be tracked until all their
 - * processes are gone. The most recently added session
 - * (i.e. the first in s-sessions) is the one that matters. */
 -
 -if (!seat_can_multi_session(s))
 +/* On seats with VTs, the VT logic defines which session is active. 
 On
 + * seats without VTs, we automatically activate the first session. */
 +if (!seat_has_vts(s)  !s-active)
  seat_set_active(s, session);
  
  return 0;
  }
  
 +bool seat_has_vts(Seat *s) {
 +assert(s);
 +
 +return seat_is_seat0(s)  s-manager-console_active_fd = 0;
 +}
 +
  bool seat_is_seat0(Seat *s) {
  assert(s);
  
 @@ -438,19 +440,13 @@ bool seat_is_seat0(Seat *s) {
  bool seat_can_multi_session(Seat *s) {
  assert(s);
  
 -if (!seat_is_seat0(s))
 -return false;
 -
 -/* If we can't watch which VT is in the foreground, we don't
 - * support VT switching */
 -
 -return s-manager-console_active_fd = 0;
 +return seat_has_vts(s);
  }
  
  bool seat_can_tty(Seat *s) {
  assert(s);
  
 -return seat_is_seat0(s)  s-manager-console_active_fd = 0;
 +return seat_has_vts(s);
  }
  
  bool seat_has_master_device(Seat *s) {
 diff --git a/src/login/logind-seat.h b/src/login/logind-seat.h
 index 47fe89a..d3438b8 100644
 --- a/src/login/logind-seat.h
 +++ b/src/login/logind-seat.h
 @@ -60,6 +60,7 @@ int seat_preallocate_vts(Seat *s);
  
  int seat_attach_session(Seat *s, Session *session);
  
 +bool seat_has_vts(Seat *s);
  bool seat_is_seat0(Seat *s);
  bool seat_can_multi_session(Seat *s);
  bool seat_can_tty(Seat *s);
 diff --git a/src/login/logind-session.c b/src/login/logind-session.c
 index 1df2a06..906115a 100644
 --- a/src/login/logind-session.c
 +++ b/src/login/logind-session.c
 @@ -206,7 +206,7 @@ int session_save(Session *s) {
  if (s-service)
  fprintf(f, SERVICE=%s\n, s-service);
  
 -if (s-seat  seat_can_multi_session(s-seat))
 +if (s-seat  seat_has_vts(s-seat))