chiark / gitweb /
logind: restore session-controller after crash
[elogind.git] / src / login / logind-session.c
index fe5fa27..0e1c40b 100644 (file)
 #include <errno.h>
 #include <string.h>
 #include <unistd.h>
-#include <sys/epoll.h>
 #include <fcntl.h>
 
-#include <systemd/sd-id128.h>
-#include <systemd/sd-messages.h>
-
+#include "sd-id128.h"
+#include "sd-messages.h"
 #include "strv.h"
 #include "util.h"
 #include "mkdir.h"
 #include "path-util.h"
 #include "fileio.h"
-#include "dbus-common.h"
+#include "audit.h"
+#include "bus-util.h"
+#include "bus-error.h"
 #include "logind-session.h"
 
+static unsigned devt_hash_func(const void *p) {
+        uint64_t u = *(const dev_t*)p;
+
+        return uint64_hash_func(&u);
+}
+
+static int devt_compare_func(const void *_a, const void *_b) {
+        dev_t a, b;
+
+        a = *(const dev_t*) _a;
+        b = *(const dev_t*) _b;
+
+        return a < b ? -1 : (a > b ? 1 : 0);
+}
+
 Session* session_new(Manager *m, const char *id) {
         Session *s;
 
@@ -53,9 +68,17 @@ Session* session_new(Manager *m, const char *id) {
                 return NULL;
         }
 
+        s->devices = hashmap_new(devt_hash_func, devt_compare_func);
+        if (!s->devices) {
+                free(s->state_file);
+                free(s);
+                return NULL;
+        }
+
         s->id = path_get_file_name(s->state_file);
 
         if (hashmap_put(m->sessions, s->id, s) < 0) {
+                hashmap_free(s->devices);
                 free(s->state_file);
                 free(s);
                 return NULL;
@@ -68,15 +91,24 @@ Session* session_new(Manager *m, const char *id) {
 }
 
 void session_free(Session *s) {
+        SessionDevice *sd;
+
         assert(s);
 
         if (s->in_gc_queue)
-                LIST_REMOVE(Session, gc_queue, s->manager->session_gc_queue, s);
+                LIST_REMOVE(gc_queue, s->manager->session_gc_queue, s);
+
+        session_remove_fifo(s);
 
         session_drop_controller(s);
 
+        while ((sd = hashmap_first(s->devices)))
+                session_device_free(sd);
+
+        hashmap_free(s->devices);
+
         if (s->user) {
-                LIST_REMOVE(Session, sessions_by_user, s->user->sessions, s);
+                LIST_REMOVE(sessions_by_user, s->user->sessions, s);
 
                 if (s->user->display == s)
                         s->user->display = NULL;
@@ -85,8 +117,10 @@ void session_free(Session *s) {
         if (s->seat) {
                 if (s->seat->active == s)
                         s->seat->active = NULL;
+                if (s->seat->pending_switch == s)
+                        s->seat->pending_switch = NULL;
 
-                LIST_REMOVE(Session, sessions_by_seat, s->seat->sessions, s);
+                LIST_REMOVE(sessions_by_seat, s->seat->sessions, s);
         }
 
         if (s->scope) {
@@ -96,8 +130,7 @@ void session_free(Session *s) {
 
         free(s->scope_job);
 
-        if (s->create_message)
-                dbus_message_unref(s->create_message);
+        sd_bus_message_unref(s->create_message);
 
         free(s->tty);
         free(s->display);
@@ -106,7 +139,6 @@ void session_free(Session *s) {
         free(s->service);
 
         hashmap_remove(s->manager->sessions, s->id);
-        session_remove_fifo(s);
 
         free(s->state_file);
         free(s);
@@ -117,12 +149,12 @@ void session_set_user(Session *s, User *u) {
         assert(!s->user);
 
         s->user = u;
-        LIST_PREPEND(Session, sessions_by_user, u->sessions, s);
+        LIST_PREPEND(sessions_by_user, u->sessions, s);
 }
 
 int session_save(Session *s) {
-        _cleanup_fclose_ FILE *f = NULL;
         _cleanup_free_ char *temp_path = NULL;
+        _cleanup_fclose_ FILE *f = NULL;
         int r = 0;
 
         assert(s);
@@ -191,7 +223,7 @@ 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)
@@ -207,6 +239,9 @@ int session_save(Session *s) {
                         (unsigned long long) s->timestamp.realtime,
                         (unsigned long long) s->timestamp.monotonic);
 
+        if (s->controller)
+                fprintf(f, "CONTROLLER=%s\n", s->controller);
+
         fflush(f);
 
         if (ferror(f) || rename(temp_path, s->state_file) < 0) {
@@ -227,12 +262,12 @@ int session_load(Session *s) {
                 *seat = NULL,
                 *vtnr = NULL,
                 *leader = NULL,
-                *audit_id = NULL,
                 *type = NULL,
                 *class = NULL,
                 *uid = NULL,
                 *realtime = NULL,
-                *monotonic = NULL;
+                *monotonic = NULL,
+                *controller = NULL;
 
         int k, r;
 
@@ -256,6 +291,7 @@ int session_load(Session *s) {
                            "UID",            &uid,
                            "REALTIME",       &realtime,
                            "MONOTONIC",      &monotonic,
+                           "CONTROLLER",     &controller,
                            NULL);
 
         if (r < 0) {
@@ -301,7 +337,7 @@ 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)) {
                 int v;
 
                 k = safe_atoi(vtnr, &v);
@@ -356,31 +392,49 @@ int session_load(Session *s) {
                         s->timestamp.monotonic = l;
         }
 
+        if (controller) {
+                if (bus_name_has_owner(s->manager->bus, controller, NULL) > 0)
+                        session_set_controller(s, controller, false);
+        }
+
         return r;
 }
 
 int session_activate(Session *s) {
-        int r;
+        unsigned int num_pending;
 
         assert(s);
         assert(s->user);
 
-        if (s->vtnr < 0)
-                return -ENOTSUP;
-
         if (!s->seat)
                 return -ENOTSUP;
 
         if (s->seat->active == s)
                 return 0;
 
-        assert(seat_is_vtconsole(s->seat));
+        /* on seats with VTs, we let VTs manage session-switching */
+        if (seat_has_vts(s->seat)) {
+                if (s->vtnr <= 0)
+                        return -ENOTSUP;
 
-        r = chvt(s->vtnr);
-        if (r < 0)
-                return r;
+                return chvt(s->vtnr);
+        }
+
+        /* On seats without VTs, we implement session-switching in logind. We
+         * try to pause all session-devices and wait until the session
+         * controller acknowledged them. Once all devices are asleep, we simply
+         * switch the active session and be done.
+         * We save the session we want to switch to in seat->pending_switch and
+         * seat_complete_switch() will perform the final switch. */
+
+        s->seat->pending_switch = s;
+
+        /* if no devices are running, immediately perform the session switch */
+        num_pending = session_device_try_pause_all(s);
+        if (!num_pending)
+                seat_complete_switch(s->seat);
 
-        return seat_set_active(s->seat, s);
+        return 0;
 }
 
 static int session_link_x11_socket(Session *s) {
@@ -450,16 +504,14 @@ done:
 }
 
 static int session_start_scope(Session *s) {
-        DBusError error;
         int r;
 
         assert(s);
         assert(s->user);
         assert(s->user->slice);
 
-        dbus_error_init(&error);
-
         if (!s->scope) {
+                _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
                 _cleanup_free_ char *description = NULL;
                 const char *kill_mode;
                 char *scope, *job;
@@ -477,9 +529,7 @@ static int session_start_scope(Session *s) {
                 r = manager_start_scope(s->manager, scope, s->leader, s->user->slice, description, "systemd-user-sessions.service", kill_mode, &error, &job);
                 if (r < 0) {
                         log_error("Failed to start session scope %s: %s %s",
-                                  scope, bus_error(&error, r), error.name);
-                        dbus_error_free(&error);
-
+                                  scope, bus_error_message(&error, r), error.name);
                         free(scope);
                         return r;
                 } else {
@@ -545,32 +595,29 @@ int session_start(Session *s) {
                 seat_save(s->seat);
 
                 if (s->seat->active == s)
-                        seat_send_changed(s->seat, "Sessions\0ActiveSession\0");
+                        seat_send_changed(s->seat, "Sessions", "ActiveSession", NULL);
                 else
-                        seat_send_changed(s->seat, "Sessions\0");
+                        seat_send_changed(s->seat, "Sessions", NULL);
         }
 
-        user_send_changed(s->user, "Sessions\0");
+        user_send_changed(s->user, "Sessions", NULL);
 
         return 0;
 }
 
 static int session_stop_scope(Session *s) {
-        DBusError error;
+        _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
         char *job;
         int r;
 
         assert(s);
 
-        dbus_error_init(&error);
-
         if (!s->scope)
                 return 0;
 
         r = manager_stop_unit(s->manager, s->scope, &error, &job);
         if (r < 0) {
-                log_error("Failed to stop session scope: %s", bus_error(&error, r));
-                dbus_error_free(&error);
+                log_error("Failed to stop session scope: %s", bus_error_message(&error, r));
                 return r;
         }
 
@@ -612,12 +659,14 @@ int session_stop(Session *s) {
         r = session_stop_scope(s);
 
         session_save(s);
+        user_save(s->user);
 
         return r;
 }
 
 int session_finalize(Session *s) {
         int r = 0;
+        SessionDevice *sd;
 
         assert(s);
 
@@ -633,6 +682,10 @@ int session_finalize(Session *s) {
                            "MESSAGE=Removed session %s.", s->id,
                            NULL);
 
+        /* Kill session devices */
+        while ((sd = hashmap_first(s->devices)))
+                session_device_free(sd);
+
         /* Remove X11 symlink */
         session_unlink_x11_socket(s);
 
@@ -649,11 +702,11 @@ int session_finalize(Session *s) {
                 if (s->seat->active == s)
                         seat_set_active(s->seat, NULL);
 
-                seat_send_changed(s->seat, "Sessions\0");
+                seat_send_changed(s->seat, "Sessions", NULL);
                 seat_save(s->seat);
         }
 
-        user_send_changed(s->user, "Sessions\0");
+        user_send_changed(s->user, "Sessions", NULL);
         user_save(s->user);
 
         return r;
@@ -767,26 +820,27 @@ void session_set_idle_hint(Session *s, bool b) {
         s->idle_hint = b;
         dual_timestamp_get(&s->idle_hint_timestamp);
 
-        session_send_changed(s,
-                             "IdleHint\0"
-                             "IdleSinceHint\0"
-                             "IdleSinceHintMonotonic\0");
+        session_send_changed(s, "IdleHint", "IdleSinceHint", "IdleSinceHintMonotonic", NULL);
 
         if (s->seat)
-                seat_send_changed(s->seat,
-                                  "IdleHint\0"
-                                  "IdleSinceHint\0"
-                                  "IdleSinceHintMonotonic\0");
-
-        user_send_changed(s->user,
-                          "IdleHint\0"
-                          "IdleSinceHint\0"
-                          "IdleSinceHintMonotonic\0");
-
-        manager_send_changed(s->manager,
-                             "IdleHint\0"
-                             "IdleSinceHint\0"
-                             "IdleSinceHintMonotonic\0");
+                seat_send_changed(s->seat, "IdleHint", "IdleSinceHint", "IdleSinceHintMonotonic", NULL);
+
+        user_send_changed(s->user, "IdleHint", "IdleSinceHint", "IdleSinceHintMonotonic", NULL);
+        manager_send_changed(s->manager, "IdleHint", "IdleSinceHint", "IdleSinceHintMonotonic", NULL);
+}
+
+static int session_dispatch_fifo(sd_event_source *es, int fd, uint32_t revents, void *userdata) {
+        Session *s = userdata;
+
+        assert(s);
+        assert(s->fifo_fd == fd);
+
+        /* EOF on the FIFO means the session died abnormally. */
+
+        session_remove_fifo(s);
+        session_stop(s);
+
+        return 1;
 }
 
 int session_create_fifo(Session *s) {
@@ -809,21 +863,20 @@ int session_create_fifo(Session *s) {
 
         /* Open reading side */
         if (s->fifo_fd < 0) {
-                struct epoll_event ev = {};
-
                 s->fifo_fd = open(s->fifo_path, O_RDONLY|O_CLOEXEC|O_NDELAY);
                 if (s->fifo_fd < 0)
                         return -errno;
 
-                r = hashmap_put(s->manager->session_fds, INT_TO_PTR(s->fifo_fd + 1), s);
+        }
+
+        if (!s->fifo_event_source) {
+                r = sd_event_add_io(s->manager->event, s->fifo_fd, 0, session_dispatch_fifo, s, &s->fifo_event_source);
                 if (r < 0)
                         return r;
 
-                ev.events = 0;
-                ev.data.u32 = FD_OTHER_BASE + s->fifo_fd;
-
-                if (epoll_ctl(s->manager->epoll_fd, EPOLL_CTL_ADD, s->fifo_fd, &ev) < 0)
-                        return -errno;
+                r = sd_event_source_set_priority(s->fifo_event_source, SD_EVENT_PRIORITY_IDLE);
+                if (r < 0)
+                        return r;
         }
 
         /* Open writing side */
@@ -837,14 +890,12 @@ int session_create_fifo(Session *s) {
 void session_remove_fifo(Session *s) {
         assert(s);
 
+        if (s->fifo_event_source)
+                s->fifo_event_source = sd_event_source_unref(s->fifo_event_source);
+
         if (s->fifo_fd >= 0) {
-                assert_se(hashmap_remove(s->manager->session_fds, INT_TO_PTR(s->fifo_fd + 1)) == s);
-                assert_se(epoll_ctl(s->manager->epoll_fd, EPOLL_CTL_DEL, s->fifo_fd, NULL) == 0);
                 close_nointr_nofail(s->fifo_fd);
                 s->fifo_fd = -1;
-
-                session_save(s);
-                user_save(s->user);
         }
 
         if (s->fifo_path) {
@@ -854,33 +905,33 @@ void session_remove_fifo(Session *s) {
         }
 }
 
-int session_check_gc(Session *s, bool drop_not_started) {
+bool session_check_gc(Session *s, bool drop_not_started) {
         int r;
 
         assert(s);
 
         if (drop_not_started && !s->started)
-                return 0;
+                return false;
 
         if (!s->user)
-                return 0;
+                return false;
 
         if (s->fifo_fd >= 0) {
                 r = pipe_eof(s->fifo_fd);
                 if (r < 0)
-                        return r;
+                        return true;
 
                 if (r == 0)
-                        return 1;
+                        return true;
         }
 
-        if (s->scope_job)
-                return 1;
+        if (s->scope_job && manager_job_is_active(s->manager, s->scope_job))
+                return true;
 
-        if (s->scope)
-                return manager_unit_is_active(s->manager, s->scope) != 0;
+        if (s->scope && manager_unit_is_active(s->manager, s->scope))
+                return true;
 
-        return 0;
+        return false;
 }
 
 void session_add_to_gc_queue(Session *s) {
@@ -889,7 +940,7 @@ void session_add_to_gc_queue(Session *s) {
         if (s->in_gc_queue)
                 return;
 
-        LIST_PREPEND(Session, gc_queue, s->manager->session_gc_queue, s);
+        LIST_PREPEND(gc_queue, s->manager->session_gc_queue, s);
         s->in_gc_queue = true;
 }
 
@@ -920,13 +971,31 @@ int session_kill(Session *s, KillWho who, int signo) {
         return manager_kill_unit(s->manager, s->scope, who, signo, NULL);
 }
 
-bool session_is_controller(Session *s, const char *sender)
-{
+bool session_is_controller(Session *s, const char *sender) {
         assert(s);
 
         return streq_ptr(s->controller, sender);
 }
 
+static void session_swap_controller(Session *s, char *name) {
+        SessionDevice *sd;
+
+        if (s->controller) {
+                manager_drop_busname(s->manager, s->controller);
+                free(s->controller);
+                s->controller = NULL;
+
+                /* Drop all devices as they're now unused. Do that after the
+                 * controller is released to avoid sending out useles
+                 * dbus signals. */
+                while ((sd = hashmap_first(s->devices)))
+                        session_device_free(sd);
+        }
+
+        s->controller = name;
+        session_save(s);
+}
+
 int session_set_controller(Session *s, const char *sender, bool force) {
         char *t;
         int r;
@@ -949,9 +1018,8 @@ int session_set_controller(Session *s, const char *sender, bool force) {
                 return r;
         }
 
-        session_drop_controller(s);
+        session_swap_controller(s, t);
 
-        s->controller = t;
         return 0;
 }
 
@@ -961,9 +1029,7 @@ void session_drop_controller(Session *s) {
         if (!s->controller)
                 return;
 
-        manager_drop_busname(s->manager, s->controller);
-        free(s->controller);
-        s->controller = NULL;
+        session_swap_controller(s, NULL);
 }
 
 static const char* const session_state_table[_SESSION_STATE_MAX] = {