#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 "sd-id128.h"

#include "sd-messages.h"

#include "strv.h"

#include "util.h"

#include "mkdir.h"

#include "path-util.h"

#include "fileio.h"

#include "audit.h"

#include "bus-util.h"

#include "bus-error.h"

#include "logind-session.h"

static unsigned long devt_hash_func(const void *p, const uint8_t hash_key[HASH_KEY_SIZE]) {

uint64_t u = *(const dev_t*)p;

return uint64_hash_func(&u, hash_key);

}

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;

assert(m);

assert(id);

assert(session_id_valid(id));

s = new0(Session, 1);

if (!s)

return NULL;

s->state_file = strappend("/run/systemd/sessions/", id);

if (!s->state_file) {

free(s);

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 = basename(s->state_file);

if (hashmap_put(m->sessions, s->id, s) < 0) {

hashmap_free(s->devices);

free(s->state_file);

free(s);

return NULL;

}

s->manager = m;

s->fifo_fd = -1;

s->vtfd = -1;

return s;

}

void session_free(Session *s) {

SessionDevice *sd;

assert(s);

if (s->in_gc_queue)

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(sessions_by_user, s->user->sessions, s);

if (s->user->display == s)

s->user->display = NULL;

}

if (s->seat) {

if (s->seat->active == s)

s->seat->active = NULL;

if (s->seat->pending_switch == s)

s->seat->pending_switch = NULL;

seat_evict_position(s->seat, 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);

free(s->display);

free(s->remote_host);

free(s->remote_user);

free(s->service);

hashmap_remove(s->manager->sessions, s->id);

free(s->state_file);

free(s);

}

void session_set_user(Session *s, User *u) {

assert(s);

assert(!s->user);

s->user = u;

LIST_PREPEND(sessions_by_user, u->sessions, s);

}

int session_save(Session *s) {

_cleanup_free_ char *temp_path = NULL;

_cleanup_fclose_ FILE *f = NULL;

int r = 0;

assert(s);

if (!s->user)

return -ESTALE;

if (!s->started)

return 0;

r = mkdir_safe_label("/run/systemd/sessions", 0755, 0, 0);

if (r < 0)

goto finish;

r = fopen_temporary(s->state_file, &f, &temp_path);

if (r < 0)

goto finish;

assert(s->user);

fchmod(fileno(f), 0644);

fprintf(f,

"# This is private data. Do not parse.\n"

"UID=%lu\n"

"USER=%s\n"

"ACTIVE=%i\n"

"STATE=%s\n"

"REMOTE=%i\n",

(unsigned long) s->user->uid,

s->user->name,

session_is_active(s),

session_state_to_string(session_get_state(s)),

s->remote);

if (s->type >= 0)

fprintf(f, "TYPE=%s\n", session_type_to_string(s->type));

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);

if (s->seat)

fprintf(f, "SEAT=%s\n", s->seat->id);

if (s->tty)

fprintf(f, "TTY=%s\n", s->tty);

if (s->display)

fprintf(f, "DISPLAY=%s\n", s->display);

if (s->remote_host)

fprintf(f, "REMOTE_HOST=%s\n", s->remote_host);

if (s->remote_user)

fprintf(f, "REMOTE_USER=%s\n", s->remote_user);

if (s->service)

fprintf(f, "SERVICE=%s\n", s->service);

if (s->seat && seat_has_vts(s->seat))

fprintf(f, "VTNR=%u\n", s->vtnr);

if (!s->vtnr)

fprintf(f, "POS=%u\n", s->pos);

if (s->leader > 0)

fprintf(f, "LEADER=%lu\n", (unsigned long) s->leader);

if (s->audit_id > 0)

fprintf(f, "AUDIT=%"PRIu32"\n", s->audit_id);

if (dual_timestamp_is_set(&s->timestamp))

fprintf(f,

"REALTIME=%llu\n"

"MONOTONIC=%llu\n",

(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) {

r = -errno;

unlink(s->state_file);

unlink(temp_path);

}

finish:

if (r < 0)

log_error("Failed to save session data for %s: %s", s->id, strerror(-r));

return r;

}

int session_load(Session *s) {

_cleanup_free_ char *remote = NULL,

*seat = NULL,

*vtnr = NULL,

*pos = NULL,

*leader = NULL,

*type = NULL,

*class = NULL,

*uid = NULL,

*realtime = NULL,

*monotonic = NULL,

*controller = NULL;

int k, r;

assert(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,

"DISPLAY", &s->display,

"REMOTE_HOST", &s->remote_host,

"REMOTE_USER", &s->remote_user,

"SERVICE", &s->service,

"VTNR", &vtnr,

"POS", &pos,

"LEADER", &leader,

"TYPE", &type,

"CLASS", &class,

"UID", &uid,

"REALTIME", &realtime,

"MONOTONIC", &monotonic,

"CONTROLLER", &controller,

NULL);

if (r < 0) {

log_error("Failed to read %s: %s", s->state_file, strerror(-r));

return r;

}

if (!s->user) {

uid_t u;

User *user;

if (!uid) {

log_error("UID not specified for session %s", s->id);

return -ENOENT;

}

r = parse_uid(uid, &u);

if (r < 0) {

log_error("Failed to parse UID value %s for session %s.", uid, s->id);

return r;

}

user = hashmap_get(s->manager->users, ULONG_TO_PTR((unsigned long) u));

if (!user) {

log_error("User of session %s not known.", s->id);

return -ENOENT;

}

session_set_user(s, user);

}

if (remote) {

k = parse_boolean(remote);

if (k >= 0)

s->remote = k;

}

if (vtnr)

safe_atou(vtnr, &s->vtnr);

if (seat && !s->seat) {

Seat *o;

o = hashmap_get(s->manager->seats, seat);

if (o)

r = seat_attach_session(o, s);

if (!o || r < 0)

log_error("Cannot attach session %s to seat %s", s->id, seat);

}

if (!s->seat || !seat_has_vts(s->seat))

s->vtnr = 0;

if (pos && s->seat) {

unsigned int npos;

safe_atou(pos, &npos);

seat_claim_position(s->seat, s, npos);

}

if (leader) {

k = parse_pid(leader, &s->leader);

if (k >= 0)

audit_session_from_pid(s->leader, &s->audit_id);

}

if (type) {

SessionType t;

t = session_type_from_string(type);

if (t >= 0)

s->type = t;

}

if (class) {

SessionClass c;

c = session_class_from_string(class);

if (c >= 0)

s->class = c;

}

if (s->fifo_path) {

int fd;

/* If we open an unopened pipe for reading we will not

fd = session_create_fifo(s);

if (fd >= 0)

close_nointr_nofail(fd);

}

if (realtime) {

unsigned long long l;

if (sscanf(realtime, "%llu", &l) > 0)

s->timestamp.realtime = l;

}

if (monotonic) {

unsigned long long l;

if (sscanf(monotonic, "%llu", &l) > 0)

s->timestamp.monotonic = l;

}

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;

}

int session_activate(Session *s) {

unsigned int num_pending;

assert(s);

assert(s->user);

if (!s->seat)

return -ENOTSUP;

if (s->seat->active == s)

return 0;

/* on seats with VTs, we let VTs manage session-switching */

if (seat_has_vts(s->seat)) {

if (!s->vtnr)

return -ENOTSUP;

return chvt(s->vtnr);

}

/* On seats without VTs, we implement session-switching in logind. We

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 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;

const char *kill_mode;

char *scope, *job;

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();

kill_mode = manager_shall_kill(s->manager, s->user->name) ? "control-group" : "none";

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_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;

assert(s);

if (!s->user)

return -ESTALE;

if (s->started)

return 0;

r = user_start(s->user);

if (r < 0)

return r;

/* Create cgroup */

r = session_start_scope(s);

if (r < 0)

return r;

log_struct(s->type == SESSION_TTY || s->type == SESSION_X11 ? LOG_INFO : LOG_DEBUG,

MESSAGE_ID(SD_MESSAGE_SESSION_START),

"SESSION_ID=%s", s->id,

"USER_ID=%s", s->user->name,

"LEADER=%lu", (unsigned long) s->leader,

"MESSAGE=New session %s of user %s.", s->id, s->user->name,

NULL);

if (!dual_timestamp_is_set(&s->timestamp))

dual_timestamp_get(&s->timestamp);

if (s->seat)

seat_read_active_vt(s->seat);

s->started = true;

/* Save session data */

session_save(s);

user_save(s->user);

session_send_signal(s, true);

if (s->seat) {

seat_save(s->seat);

if (s->seat->active == s)

seat_send_changed(s->seat, "Sessions", "ActiveSession", NULL);

else

seat_send_changed(s->seat, "Sessions", NULL);

}

user_send_changed(s->user, "Sessions", NULL);

return 0;

}

static int session_stop_scope(Session *s) {

_cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;

char *job;

int r;

assert(s);

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_message(&error, r));

return r;

}

free(s->scope_job);

s->scope_job = job;

return 0;

}

int session_stop(Session *s) {

int r;

assert(s);

if (!s->user)

return -ESTALE;

/* Kill cgroup */

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);

if (!s->user)

return -ESTALE;

if (s->started)

log_struct(s->type == SESSION_TTY || s->type == SESSION_X11 ? LOG_INFO : LOG_DEBUG,

MESSAGE_ID(SD_MESSAGE_SESSION_STOP),

"SESSION_ID=%s", s->id,

"USER_ID=%s", s->user->name,

"LEADER=%lu", (unsigned long) s->leader,

"MESSAGE=Removed session %s.", s->id,

NULL);

/* Kill session devices */

while ((sd = hashmap_first(s->devices)))

session_device_free(sd);

unlink(s->state_file);

session_add_to_gc_queue(s);

user_add_to_gc_queue(s->user);

if (s->started) {

session_send_signal(s, false);

s->started = false;

}

if (s->seat) {

if (s->seat->active == s)

seat_set_active(s->seat, NULL);

seat_send_changed(s->seat, "Sessions", NULL);

seat_save(s->seat);

}

user_send_changed(s->user, "Sessions", NULL);

user_save(s->user);

return r;

}

bool session_is_active(Session *s) {

assert(s);

if (!s->seat)

return true;

return s->seat->active == s;

}

static int get_tty_atime(const char *tty, usec_t *atime) {

_cleanup_free_ char *p = NULL;

struct stat st;

assert(tty);

assert(atime);

if (!path_is_absolute(tty)) {

p = strappend("/dev/", tty);

if (!p)

return -ENOMEM;

tty = p;

} else if (!path_startswith(tty, "/dev/"))

return -ENOENT;

if (lstat(tty, &st) < 0)

return -errno;

*atime = timespec_load(&st.st_atim);

return 0;

}

static int get_process_ctty_atime(pid_t pid, usec_t *atime) {

_cleanup_free_ char *p = NULL;

int r;

assert(pid > 0);

assert(atime);

r = get_ctty(pid, NULL, &p);

if (r < 0)

return r;

return get_tty_atime(p, atime);

}

int session_get_idle_hint(Session *s, dual_timestamp *t) {

usec_t atime = 0, n;

int r;

assert(s);

/* Explicit idle hint is set */

if (s->idle_hint) {

if (t)

*t = s->idle_hint_timestamp;

return s->idle_hint;

}

/* Graphical sessions should really implement a real

if (s->display)

goto dont_know;

/* For sessions with an explicitly configured tty, let's check

if (s->tty) {

r = get_tty_atime(s->tty, &atime);

if (r >= 0)

goto found_atime;

}

/* For sessions with a leader but no explicitly configured

if (s->leader > 0) {

r = get_process_ctty_atime(s->leader, &atime);

if (r >= 0)

goto found_atime;

}

dont_know:

if (t)

*t = s->idle_hint_timestamp;

return 0;

found_atime:

if (t)

dual_timestamp_from_realtime(t, atime);

n = now(CLOCK_REALTIME);

if (s->manager->idle_action_usec <= 0)

return 0;

return atime + s->manager->idle_action_usec <= n;

}

void session_set_idle_hint(Session *s, bool b) {

assert(s);

if (s->idle_hint == b)

return;

s->idle_hint = b;

dual_timestamp_get(&s->idle_hint_timestamp);

session_send_changed(s, "IdleHint", "IdleSinceHint", "IdleSinceHintMonotonic", NULL);

if (s->seat)

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) {

int r;

assert(s);

/* Create FIFO */

if (!s->fifo_path) {

r = mkdir_safe_label("/run/systemd/sessions", 0755, 0, 0);

if (r < 0)

return r;

if (asprintf(&s->fifo_path, "/run/systemd/sessions/%s.ref", s->id) < 0)

return -ENOMEM;

if (mkfifo(s->fifo_path, 0600) < 0 && errno != EEXIST)

return -errno;

}

/* Open reading side */

if (s->fifo_fd < 0) {

s->fifo_fd = open(s->fifo_path, O_RDONLY|O_CLOEXEC|O_NDELAY);

if (s->fifo_fd < 0)

return -errno;

}

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;

r = sd_event_source_set_priority(s->fifo_event_source, SD_EVENT_PRIORITY_IDLE);

if (r < 0)

return r;

}

/* Open writing side */

r = open(s->fifo_path, O_WRONLY|O_CLOEXEC|O_NDELAY);

if (r < 0)

return -errno;

return r;

}

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) {

close_nointr_nofail(s->fifo_fd);

s->fifo_fd = -1;

}

if (s->fifo_path) {

unlink(s->fifo_path);

free(s->fifo_path);

s->fifo_path = NULL;

}

}

bool session_check_gc(Session *s, bool drop_not_started) {

int r;

assert(s);

if (drop_not_started && !s->started)

return false;

if (!s->user)

return false;

if (s->fifo_fd >= 0) {

r = pipe_eof(s->fifo_fd);

if (r < 0)

return true;

if (r == 0)

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;

}

void session_add_to_gc_queue(Session *s) {

assert(s);

if (s->in_gc_queue)

return;

LIST_PREPEND(gc_queue, s->manager->session_gc_queue, s);

s->in_gc_queue = true;

}

SessionState session_get_state(Session *s) {

assert(s);

if (s->scope_job)

return SESSION_OPENING;

if (s->fifo_fd < 0)

return SESSION_CLOSING;

if (session_is_active(s))

return SESSION_ACTIVE;

return SESSION_ONLINE;

}

int session_kill(Session *s, KillWho who, int signo) {

assert(s);

if (!s->scope)

return -ESRCH;

return manager_kill_unit(s->manager, s->scope, who, signo, NULL);

}

static int session_open_vt(Session *s) {

char path[128];

if (!s->vtnr)

return -1;

if (s->vtfd >= 0)

return s->vtfd;

sprintf(path, "/dev/tty%u", 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.

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 %u 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);

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

while ((sd = hashmap_first(s->devices)))

session_device_free(sd);

if (!name)

session_restore_vt(s);

}

s->controller = name;

session_save(s);

}

int session_set_controller(Session *s, const char *sender, bool force) {

char *t;

int r;

assert(s);

assert(sender);

if (session_is_controller(s, sender))

return 0;

if (s->controller && !force)

return -EBUSY;

t = strdup(sender);

if (!t)

return -ENOMEM;

r = manager_watch_busname(s->manager, sender);

if (r) {

free(t);

return r;

}

session_swap_controller(s, t);

/* When setting a session controller, we forcibly mute the VT and set

session_mute_vt(s);

return 0;

}

void session_drop_controller(Session *s) {

assert(s);

if (!s->controller)

return;

session_swap_controller(s, NULL);

}

static const char* const session_state_table[_SESSION_STATE_MAX] = {

[SESSION_OPENING] = "opening",

[SESSION_ONLINE] = "online",

[SESSION_ACTIVE] = "active",

[SESSION_CLOSING] = "closing"

};

DEFINE_STRING_TABLE_LOOKUP(session_state, SessionState);

static const char* const session_type_table[_SESSION_TYPE_MAX] = {

[SESSION_TTY] = "tty",

[SESSION_X11] = "x11",

[SESSION_UNSPECIFIED] = "unspecified"

};

DEFINE_STRING_TABLE_LOOKUP(session_type, SessionType);

static const char* const session_class_table[_SESSION_CLASS_MAX] = {

[SESSION_USER] = "user",

[SESSION_GREETER] = "greeter",

[SESSION_LOCK_SCREEN] = "lock-screen",

[SESSION_BACKGROUND] = "background"

};

DEFINE_STRING_TABLE_LOOKUP(session_class, SessionClass);

static const char* const kill_who_table[_KILL_WHO_MAX] = {

[KILL_LEADER] = "leader",

[KILL_ALL] = "all"

};

DEFINE_STRING_TABLE_LOOKUP(kill_who, KillWho);