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authorDavid Herrmann <dh.herrmann@gmail.com>2013-11-28 15:10:24 +0100
committerDavid Herrmann <dh.herrmann@gmail.com>2013-11-28 15:16:49 +0100
commit90a18413f8be577a649900eca977e060273f2b5b (patch)
treebb5ef76e3e1bdf9492f347bed84358b4d237df50
parent6d33772f9ae6769c557e2267d16b7d31f67db914 (diff)
logind: mute/restore VT on behalf of session controllers
If a session process calls TakeControl(), we now put the VT into KD_GRAPHICS+K_OFF mode. This way, the new session controller can solely rely on the logind-dbus API to manage the session. Once the controller exits or calls ReleaseControl(), we restore the VT. We also restore it, if we lost a controller during crash/restart (but only if there really *was* a controller previously). Note that we also must put the VT into VT_PROCESS mode. We want VT_AUTO semantics, but VT_AUTO+KD_GRAPHICS actually disables *all* VT switches (who came up with that great idea?). Hence, we set VT_PROCESS for logind but acknowledge *all* requests immediately. If a compositor wants custom VT setups, they can still get this by *first* calling TakeControl() and afterwards setting up the VT. logind doesn't touch the VT during controller runtime, only during setup/teardown. This is actually what weston already does.
-rw-r--r--src/login/logind-session.c117
-rw-r--r--src/login/logind-session.h7
2 files changed, 122 insertions, 2 deletions
diff --git a/src/login/logind-session.c b/src/login/logind-session.c
index 0e1c40b4eb..c12683c60c 100644
--- a/src/login/logind-session.c
+++ b/src/login/logind-session.c
@@ -20,9 +20,13 @@
***/
#include <errno.h>
+#include <fcntl.h>
+#include <linux/vt.h>
+#include <linux/kd.h>
+#include <signal.h>
#include <string.h>
+#include <sys/ioctl.h>
#include <unistd.h>
-#include <fcntl.h>
#include "sd-id128.h"
#include "sd-messages.h"
@@ -86,6 +90,7 @@ Session* session_new(Manager *m, const char *id) {
s->manager = m;
s->fifo_fd = -1;
+ s->vtfd = -1;
return s;
}
@@ -395,6 +400,8 @@ int session_load(Session *s) {
if (controller) {
if (bus_name_has_owner(s->manager->bus, controller, NULL) > 0)
session_set_controller(s, controller, false);
+ else
+ session_restore_vt(s);
}
return r;
@@ -971,6 +978,101 @@ int session_kill(Session *s, KillWho who, int signo) {
return manager_kill_unit(s->manager, s->scope, who, signo, NULL);
}
+static int session_open_vt(Session *s) {
+ char path[128];
+
+ if (s->vtnr <= 0)
+ return -1;
+
+ if (s->vtfd >= 0)
+ return s->vtfd;
+
+ sprintf(path, "/dev/tty%d", s->vtnr);
+ s->vtfd = open(path, O_RDWR | O_CLOEXEC | O_NONBLOCK | O_NOCTTY);
+ if (s->vtfd < 0) {
+ log_error("cannot open VT %s of session %s: %m", path, s->id);
+ return -1;
+ }
+
+ return s->vtfd;
+}
+
+static int session_vt_fn(sd_event_source *source, const struct signalfd_siginfo *si, void *data) {
+ Session *s = data;
+
+ if (s->vtfd >= 0)
+ ioctl(s->vtfd, VT_RELDISP, 1);
+
+ return 0;
+}
+
+void session_mute_vt(Session *s) {
+ int vt, r;
+ struct vt_mode mode = { 0 };
+ sigset_t mask;
+
+ vt = session_open_vt(s);
+ if (vt < 0)
+ return;
+
+ r = ioctl(vt, KDSKBMODE, K_OFF);
+ if (r < 0)
+ goto error;
+
+ r = ioctl(vt, KDSETMODE, KD_GRAPHICS);
+ if (r < 0)
+ goto error;
+
+ sigemptyset(&mask);
+ sigaddset(&mask, SIGUSR1);
+ sigprocmask(SIG_BLOCK, &mask, NULL);
+
+ r = sd_event_add_signal(s->manager->event, SIGUSR1, session_vt_fn, s, &s->vt_source);
+ if (r < 0)
+ goto error;
+
+ /* Oh, thanks to the VT layer, VT_AUTO does not work with KD_GRAPHICS.
+ * So we need a dummy handler here which just acknowledges *all* VT
+ * switch requests. */
+ mode.mode = VT_PROCESS;
+ mode.relsig = SIGUSR1;
+ mode.acqsig = SIGUSR1;
+ r = ioctl(vt, VT_SETMODE, &mode);
+ if (r < 0)
+ goto error;
+
+ return;
+
+error:
+ log_error("cannot mute VT %d for session %s (%d/%d)", s->vtnr, s->id, r, errno);
+ session_restore_vt(s);
+}
+
+void session_restore_vt(Session *s) {
+ _cleanup_free_ char *utf8;
+ int vt, kb = K_XLATE;
+ struct vt_mode mode = { 0 };
+
+ vt = session_open_vt(s);
+ if (vt < 0)
+ return;
+
+ sd_event_source_unref(s->vt_source);
+ s->vt_source = NULL;
+
+ ioctl(vt, KDSETMODE, KD_TEXT);
+
+ if (read_one_line_file("/sys/module/vt/parameters/default_utf8", &utf8) >= 0 && *utf8 == '1')
+ kb = K_UNICODE;
+ ioctl(vt, KDSKBMODE, kb);
+
+ mode.mode = VT_AUTO;
+ ioctl(vt, VT_SETMODE, &mode);
+
+ close_nointr_nofail(vt);
+ s->vtfd = -1;
+}
+
bool session_is_controller(Session *s, const char *sender) {
assert(s);
@@ -990,6 +1092,9 @@ static void session_swap_controller(Session *s, char *name) {
* dbus signals. */
while ((sd = hashmap_first(s->devices)))
session_device_free(sd);
+
+ if (!name)
+ session_restore_vt(s);
}
s->controller = name;
@@ -1020,6 +1125,16 @@ int session_set_controller(Session *s, const char *sender, bool force) {
session_swap_controller(s, t);
+ /* When setting a session controller, we forcibly mute the VT and set
+ * it into graphics-mode. Applications can override that by changing
+ * VT state after calling TakeControl(). However, this serves as a good
+ * default and well-behaving controllers can now ignore VTs entirely.
+ * Note that we reset the VT on ReleaseControl() and if the controller
+ * exits.
+ * If logind crashes/restarts, we restore the controller during restart
+ * or reset the VT in case it crashed/exited, too. */
+ session_mute_vt(s);
+
return 0;
}
diff --git a/src/login/logind-session.h b/src/login/logind-session.h
index f7a9dbc249..aab39b72e3 100644
--- a/src/login/logind-session.h
+++ b/src/login/logind-session.h
@@ -89,8 +89,10 @@ struct Session {
char *scope;
char *scope_job;
- int vtnr;
Seat *seat;
+ int vtnr;
+ int vtfd;
+ sd_event_source *vt_source;
pid_t leader;
uint32_t audit_id;
@@ -162,6 +164,9 @@ SessionClass session_class_from_string(const char *s) _pure_;
const char *kill_who_to_string(KillWho k) _const_;
KillWho kill_who_from_string(const char *s) _pure_;
+void session_mute_vt(Session *s);
+void session_restore_vt(Session *s);
+
bool session_is_controller(Session *s, const char *sender);
int session_set_controller(Session *s, const char *sender, bool force);
void session_drop_controller(Session *s);