chiark / gitweb /
logind: get a fresh file descriptor to clean up a VT
[elogind.git] / src / login / logind-session.c
index 08ca807..1a5c76b 100644 (file)
@@ -37,6 +37,8 @@
 #include "bus-util.h"
 #include "bus-error.h"
 #include "logind-session.h"
+#include "formats-util.h"
+#include "terminal-util.h"
 
 #define RELEASE_USEC (20*USEC_PER_SEC)
 
@@ -118,6 +120,13 @@ void session_free(Session *s) {
                 LIST_REMOVE(sessions_by_seat, s->seat->sessions, s);
         }
 
+        if (s->scope) {
+                hashmap_remove(s->manager->session_units, s->scope);
+                free(s->scope);
+        }
+
+        free(s->scope_job);
+
         sd_bus_message_unref(s->create_message);
 
         free(s->tty);
@@ -185,6 +194,11 @@ int session_save(Session *s) {
         if (s->class >= 0)
                 fprintf(f, "CLASS=%s\n", session_class_to_string(s->class));
 
+        if (s->scope)
+                fprintf(f, "SCOPE=%s\n", s->scope);
+        if (s->scope_job)
+                fprintf(f, "SCOPE_JOB=%s\n", s->scope_job);
+
         if (s->fifo_path)
                 fprintf(f, "FIFO=%s\n", s->fifo_path);
 
@@ -250,7 +264,7 @@ int session_save(Session *s) {
                 fprintf(f, "VTNR=%u\n", s->vtnr);
 
         if (!s->vtnr)
-                fprintf(f, "POS=%u\n", s->pos);
+                fprintf(f, "POSITION=%u\n", s->position);
 
         if (s->leader > 0)
                 fprintf(f, "LEADER="PID_FMT"\n", s->leader);
@@ -288,7 +302,7 @@ int session_load(Session *s) {
                 *seat = NULL,
                 *vtnr = NULL,
                 *state = NULL,
-                *pos = NULL,
+                *position = NULL,
                 *leader = NULL,
                 *type = NULL,
                 *class = NULL,
@@ -303,6 +317,8 @@ int session_load(Session *s) {
 
         r = parse_env_file(s->state_file, NEWLINE,
                            "REMOTE",         &remote,
+                           "SCOPE",          &s->scope,
+                           "SCOPE_JOB",      &s->scope_job,
                            "FIFO",           &s->fifo_path,
                            "SEAT",           &seat,
                            "TTY",            &s->tty,
@@ -313,7 +329,7 @@ int session_load(Session *s) {
                            "DESKTOP",        &s->desktop,
                            "VTNR",           &vtnr,
                            "STATE",          &state,
-                           "POS",            &pos,
+                           "POSITION",       &position,
                            "LEADER",         &leader,
                            "TYPE",           &type,
                            "CLASS",          &class,
@@ -372,10 +388,10 @@ int session_load(Session *s) {
         if (!s->seat || !seat_has_vts(s->seat))
                 s->vtnr = 0;
 
-        if (pos && s->seat) {
+        if (position && s->seat) {
                 unsigned int npos;
 
-                safe_atou(pos, &npos);
+                safe_atou(position, &npos);
                 seat_claim_position(s->seat, s, npos);
         }
 
@@ -477,6 +493,46 @@ int session_activate(Session *s) {
         return 0;
 }
 
+static int session_start_scope(Session *s) {
+        int r;
+
+        assert(s);
+        assert(s->user);
+        assert(s->user->slice);
+
+        if (!s->scope) {
+                _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
+                _cleanup_free_ char *description = NULL;
+                char *scope, *job = NULL;
+
+                description = strjoin("Session ", s->id, " of user ", s->user->name, NULL);
+                if (!description)
+                        return log_oom();
+
+                scope = strjoin("session-", s->id, ".scope", NULL);
+                if (!scope)
+                        return log_oom();
+
+                r = manager_start_scope(s->manager, scope, s->leader, s->user->slice, description, "systemd-logind.service", "systemd-user-sessions.service", &error, &job);
+                if (r < 0) {
+                        log_error("Failed to start session scope %s: %s %s",
+                                  scope, bus_error_message(&error, r), error.name);
+                        free(scope);
+                        return r;
+                } else {
+                        s->scope = scope;
+
+                        free(s->scope_job);
+                        s->scope_job = job;
+                }
+        }
+
+        if (s->scope)
+                hashmap_put(s->manager->session_units, s->scope, s);
+
+        return 0;
+}
+
 int session_start(Session *s) {
         int r;
 
@@ -492,6 +548,11 @@ int session_start(Session *s) {
         if (r < 0)
                 return r;
 
+        /* Create cgroup */
+        r = session_start_scope(s);
+        if (r < 0)
+                return r;
+
         log_struct(s->class == SESSION_BACKGROUND ? LOG_DEBUG : LOG_INFO,
                    LOG_MESSAGE_ID(SD_MESSAGE_SESSION_START),
                    "SESSION_ID=%s", s->id,
@@ -529,8 +590,38 @@ int session_start(Session *s) {
         return 0;
 }
 
+static int session_stop_scope(Session *s, bool force) {
+        _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
+        char *job = NULL;
+        int r;
+
+        assert(s);
+
+        if (!s->scope)
+                return 0;
+
+        if (force || manager_shall_kill(s->manager, s->user->name)) {
+                r = manager_stop_unit(s->manager, s->scope, &error, &job);
+                if (r < 0) {
+                        log_error("Failed to stop session scope: %s", bus_error_message(&error, r));
+                        return r;
+                }
+
+                free(s->scope_job);
+                s->scope_job = job;
+        } else {
+                r = manager_abandon_scope(s->manager, s->scope, &error);
+                if (r < 0) {
+                        log_error("Failed to abandon session scope: %s", bus_error_message(&error, r));
+                        return r;
+                }
+        }
+
+        return 0;
+}
+
 int session_stop(Session *s, bool force) {
-        int r = 0;
+        int r;
 
         assert(s);
 
@@ -539,9 +630,15 @@ int session_stop(Session *s, bool force) {
 
         s->timer_event_source = sd_event_source_unref(s->timer_event_source);
 
+        if (s->seat)
+                seat_evict_position(s->seat, s);
+
         /* We are going down, don't care about FIFOs anymore */
         session_remove_fifo(s);
 
+        /* Kill cgroup */
+        r = session_stop_scope(s, force);
+
         s->stopping = true;
 
         user_elect_display(s->user);
@@ -572,6 +669,9 @@ int session_finalize(Session *s) {
 
         s->timer_event_source = sd_event_source_unref(s->timer_event_source);
 
+        if (s->seat)
+                seat_evict_position(s->seat, s);
+
         /* Kill session devices */
         while ((sd = hashmap_first(s->devices)))
                 session_device_free(sd);
@@ -827,6 +927,12 @@ bool session_check_gc(Session *s, bool drop_not_started) {
                         return true;
         }
 
+        if (s->scope_job && manager_job_is_active(s->manager, s->scope_job))
+                return true;
+
+        if (s->scope && manager_unit_is_active(s->manager, s->scope))
+                return true;
+
         return false;
 }
 
@@ -847,7 +953,7 @@ SessionState session_get_state(Session *s) {
         if (s->stopping || s->timer_event_source)
                 return SESSION_CLOSING;
 
-        if (s->fifo_fd < 0)
+        if (s->scope_job || s->fifo_fd < 0)
                 return SESSION_OPENING;
 
         if (session_is_active(s))
@@ -859,8 +965,10 @@ SessionState session_get_state(Session *s) {
 int session_kill(Session *s, KillWho who, int signo) {
         assert(s);
 
-        /* No way to kill the session without cgroups.  */
-        return -ESRCH;
+        if (!s->scope)
+                return -ESRCH;
+
+        return manager_kill_unit(s->manager, s->scope, who, signo, NULL);
 }
 
 static int session_open_vt(Session *s) {
@@ -873,7 +981,7 @@ static int session_open_vt(Session *s) {
                 return s->vtfd;
 
         sprintf(path, "/dev/tty%u", s->vtnr);
-        s->vtfd = open(path, O_RDWR | O_CLOEXEC | O_NONBLOCK | O_NOCTTY);
+        s->vtfd = open_terminal(path, O_RDWR | O_CLOEXEC | O_NONBLOCK | O_NOCTTY);
         if (s->vtfd < 0)
                 return log_error_errno(errno, "cannot open VT %s of session %s: %m", path, s->id);
 
@@ -937,7 +1045,18 @@ void session_restore_vt(Session *s) {
         int vt, kb = K_XLATE;
         struct vt_mode mode = { 0 };
 
+        /* We need to get a fresh handle to the virtual terminal,
+         * since the old file-descriptor is potentially in a hung-up
+         * state after the controlling process exited; we do a
+         * little dance to avoid having the terminal be available
+         * for reuse before we've cleaned it up.
+         */
+        int old_fd = s->vtfd;
+        s->vtfd = -1;
+
         vt = session_open_vt(s);
+        safe_close(old_fd);
+
         if (vt < 0)
                 return;