#include <assert.h>

#include <errno.h>

#include <unistd.h>

#include <fcntl.h>

#include <sys/ioctl.h>

#include <linux/vt.h>

#include <string.h>

#include "sd-id128.h"

#include "sd-messages.h"

#include "logind-seat.h"

#include "logind-acl.h"

#include "util.h"

#include "mkdir.h"

#include "path-util.h"

Seat *seat_new(Manager *m, const char *id) {

Seat *s;

assert(m);

assert(id);

s = new0(Seat, 1);

if (!s)

return NULL;

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

if (!s->state_file) {

free(s);

return NULL;

}

s->id = basename(s->state_file);

s->manager = m;

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

free(s->state_file);

free(s);

return NULL;

}

return s;

}

void seat_free(Seat *s) {

assert(s);

if (s->in_gc_queue)

LIST_REMOVE(gc_queue, s->manager->seat_gc_queue, s);

while (s->sessions)

session_free(s->sessions);

assert(!s->active);

while (s->devices)

device_free(s->devices);

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

free(s->positions);

free(s->state_file);

free(s);

}

int seat_save(Seat *s) {

_cleanup_free_ char *temp_path = NULL;

_cleanup_fclose_ FILE *f = NULL;

int r;

assert(s);

if (!s->started)

return 0;

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

if (r < 0)

goto finish;

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

if (r < 0)

goto finish;

fchmod(fileno(f), 0644);

fprintf(f,

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

"IS_SEAT0=%i\n"

"CAN_MULTI_SESSION=%i\n"

"CAN_TTY=%i\n"

"CAN_GRAPHICAL=%i\n",

seat_is_seat0(s),

seat_can_multi_session(s),

seat_can_tty(s),

seat_can_graphical(s));

if (s->active) {

assert(s->active->user);

fprintf(f,

"ACTIVE=%s\n"

"ACTIVE_UID=%lu\n",

s->active->id,

(unsigned long) s->active->user->uid);

}

if (s->sessions) {

Session *i;

fputs("SESSIONS=", f);

LIST_FOREACH(sessions_by_seat, i, s->sessions) {

fprintf(f,

"%s%c",

i->id,

i->sessions_by_seat_next ? ' ' : '\n');

}

fputs("UIDS=", f);

LIST_FOREACH(sessions_by_seat, i, s->sessions)

fprintf(f,

"%lu%c",

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

i->sessions_by_seat_next ? ' ' : '\n');

}

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 seat data for %s: %s", s->id, strerror(-r));

return r;

}

int seat_load(Seat *s) {

assert(s);

/* There isn't actually anything to read here ... */

return 0;

}

static int vt_allocate(unsigned int vtnr) {

_cleanup_free_ char *p = NULL;

_cleanup_close_ int fd = -1;

assert(vtnr >= 1);

if (asprintf(&p, "/dev/tty%u", vtnr) < 0)

return -ENOMEM;

fd = open_terminal(p, O_RDWR|O_NOCTTY|O_CLOEXEC);

if (fd < 0)

return -errno;

return 0;

}

int seat_preallocate_vts(Seat *s) {

int r = 0;

unsigned i;

assert(s);

assert(s->manager);

log_debug("Preallocating VTs...");

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

return 0;

if (!seat_has_vts(s))

return 0;

for (i = 1; i <= s->manager->n_autovts; i++) {

int q;

q = vt_allocate(i);

if (q < 0) {

log_error("Failed to preallocate VT %i: %s", i, strerror(-q));

r = q;

}

}

return r;

}

int seat_apply_acls(Seat *s, Session *old_active) {

int r;

assert(s);

r = devnode_acl_all(s->manager->udev,

s->id,

false,

!!old_active, old_active ? old_active->user->uid : 0,

!!s->active, s->active ? s->active->user->uid : 0);

if (r < 0)

log_error("Failed to apply ACLs: %s", strerror(-r));

return r;

}

int seat_set_active(Seat *s, Session *session) {

Session *old_active;

assert(s);

assert(!session || session->seat == s);

if (session == s->active)

return 0;

old_active = s->active;

s->active = session;

if (old_active) {

session_device_pause_all(old_active);

session_send_changed(old_active, "Active", NULL);

}

seat_apply_acls(s, old_active);

if (session && session->started) {

session_send_changed(session, "Active", NULL);

session_device_resume_all(session);

}

if (!session || session->started)

seat_send_changed(s, "ActiveSession", NULL);

seat_save(s);

if (session) {

session_save(session);

user_save(session->user);

}

if (old_active) {

session_save(old_active);

if (!session || session->user != old_active->user)

user_save(old_active->user);

}

return 0;

}

int seat_switch_to(Seat *s, unsigned int num) {

/* Public session positions skip 0 (there is only F1-F12). Maybe it

if (!num)

return -EINVAL;

if (num >= s->position_count || !s->positions[num])

return -EINVAL;

return session_activate(s->positions[num]);

}

int seat_switch_to_next(Seat *s) {

unsigned int start, i;

if (!s->position_count)

return -EINVAL;

start = 1;

if (s->active && s->active->pos > 0)

start = s->active->pos;

for (i = start + 1; i < s->position_count; ++i)

if (s->positions[i])

return session_activate(s->positions[i]);

for (i = 1; i < start; ++i)

if (s->positions[i])

return session_activate(s->positions[i]);

return -EINVAL;

}

int seat_switch_to_previous(Seat *s) {

unsigned int start, i;

if (!s->position_count)

return -EINVAL;

start = 1;

if (s->active && s->active->pos > 0)

start = s->active->pos;

for (i = start - 1; i > 0; --i)

if (s->positions[i])

return session_activate(s->positions[i]);

for (i = s->position_count - 1; i > start; --i)

if (s->positions[i])

return session_activate(s->positions[i]);

return -EINVAL;

}

int seat_active_vt_changed(Seat *s, unsigned int vtnr) {

Session *i, *new_active = NULL;

int r;

assert(s);

assert(vtnr >= 1);

if (!seat_has_vts(s))

return -EINVAL;

log_debug("VT changed to %u", vtnr);

LIST_FOREACH(sessions_by_seat, i, s->sessions)

if (i->vtnr == vtnr) {

new_active = i;

break;

}

r = seat_set_active(s, new_active);

manager_spawn_autovt(s->manager, vtnr);

return r;

}

int seat_read_active_vt(Seat *s) {

char t[64];

ssize_t k;

unsigned int vtnr;

int r;

assert(s);

if (!seat_has_vts(s))

return 0;

lseek(s->manager->console_active_fd, SEEK_SET, 0);

k = read(s->manager->console_active_fd, t, sizeof(t)-1);

if (k <= 0) {

log_error("Failed to read current console: %s", k < 0 ? strerror(-errno) : "EOF");

return k < 0 ? -errno : -EIO;

}

t[k] = 0;

truncate_nl(t);

if (!startswith(t, "tty")) {

log_error("Hm, /sys/class/tty/tty0/active is badly formatted.");

return -EIO;

}

r = safe_atou(t+3, &vtnr);

if (r < 0) {

log_error("Failed to parse VT number %s", t+3);

return r;

}

if (!vtnr) {

log_error("VT number invalid: %s", t+3);

return -EIO;

}

return seat_active_vt_changed(s, vtnr);

}

int seat_start(Seat *s) {

assert(s);

if (s->started)

return 0;

log_struct(LOG_INFO,

MESSAGE_ID(SD_MESSAGE_SEAT_START),

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

"MESSAGE=New seat %s.", s->id,

NULL);

/* Initialize VT magic stuff */

seat_preallocate_vts(s);

/* Read current VT */

seat_read_active_vt(s);

s->started = true;

/* Save seat data */

seat_save(s);

seat_send_signal(s, true);

return 0;

}

int seat_stop(Seat *s) {

int r = 0;

assert(s);

if (s->started)

log_struct(LOG_INFO,

MESSAGE_ID(SD_MESSAGE_SEAT_STOP),

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

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

NULL);

seat_stop_sessions(s);

unlink(s->state_file);

seat_add_to_gc_queue(s);

if (s->started)

seat_send_signal(s, false);

s->started = false;

return r;

}

int seat_stop_sessions(Seat *s) {

Session *session;

int r = 0, k;

assert(s);

LIST_FOREACH(sessions_by_seat, session, s->sessions) {

k = session_stop(session);

if (k < 0)

r = k;

}

return r;

}

void seat_evict_position(Seat *s, Session *session) {

unsigned int pos = session->pos;

session->pos = 0;

if (!pos)

return;

if (pos < s->position_count && s->positions[pos] == session)

s->positions[pos] = NULL;

}

void seat_claim_position(Seat *s, Session *session, unsigned int pos) {

/* with VTs, the position is always the same as the VTnr */

if (seat_has_vts(s))

pos = session->vtnr;

if (!GREEDY_REALLOC0(s->positions, s->position_count, pos + 1))

return;

seat_evict_position(s, session);

session->pos = pos;

if (pos > 0 && !s->positions[pos])

s->positions[pos] = session;

}

static void seat_assign_position(Seat *s, Session *session) {

unsigned int pos;

if (session->pos > 0)

return;

for (pos = 1; pos < s->position_count; ++pos)

if (!s->positions[pos])

break;

seat_claim_position(s, session, pos);

}

int seat_attach_session(Seat *s, Session *session) {

assert(s);

assert(session);

assert(!session->seat);

if (!seat_has_vts(s) != !session->vtnr)

return -EINVAL;

session->seat = s;

LIST_PREPEND(sessions_by_seat, s->sessions, session);

seat_assign_position(s, session);

seat_send_changed(s, "Sessions", NULL);

/* On seats with VTs, the VT logic defines which session is active. On

if (!seat_has_vts(s))

seat_set_active(s, session);

return 0;

}

void seat_complete_switch(Seat *s) {

Session *session;

assert(s);

/* if no session-switch is pending or if it got canceled, do nothing */

if (!s->pending_switch)

return;

session = s->pending_switch;

s->pending_switch = NULL;

seat_set_active(s, session);

}

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);

return s->manager->seat0 == s;

}

bool seat_can_multi_session(Seat *s) {

assert(s);

return seat_has_vts(s);

}

bool seat_can_tty(Seat *s) {

assert(s);

return seat_has_vts(s);

}

bool seat_has_master_device(Seat *s) {

assert(s);

/* device list is ordered by "master" flag */

return !!s->devices && s->devices->master;

}

bool seat_can_graphical(Seat *s) {

assert(s);

return seat_has_master_device(s);

}

int seat_get_idle_hint(Seat *s, dual_timestamp *t) {

Session *session;

bool idle_hint = true;

dual_timestamp ts = { 0, 0 };

assert(s);

LIST_FOREACH(sessions_by_seat, session, s->sessions) {

dual_timestamp k;

int ih;

ih = session_get_idle_hint(session, &k);

if (ih < 0)

return ih;

if (!ih) {

if (!idle_hint) {

if (k.monotonic > ts.monotonic)

ts = k;

} else {

idle_hint = false;

ts = k;

}

} else if (idle_hint) {

if (k.monotonic > ts.monotonic)

ts = k;

}

}

if (t)

*t = ts;

return idle_hint;

}

bool seat_check_gc(Seat *s, bool drop_not_started) {

assert(s);

if (drop_not_started && !s->started)

return false;

if (seat_is_seat0(s))

return true;

return seat_has_master_device(s);

}

void seat_add_to_gc_queue(Seat *s) {

assert(s);

if (s->in_gc_queue)

return;

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

s->in_gc_queue = true;

}

static bool seat_name_valid_char(char c) {

return

(c >= 'a' && c <= 'z') ||

(c >= 'A' && c <= 'Z') ||

(c >= '0' && c <= '9') ||

c == '-' ||

c == '_';

}

bool seat_name_is_valid(const char *name) {

const char *p;

assert(name);

if (!startswith(name, "seat"))

return false;

if (!name[4])

return false;

for (p = name; *p; p++)

if (!seat_name_valid_char(*p))

return false;

if (strlen(name) > 255)

return false;

return true;

}