/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
/***
This file is part of systemd.
Copyright 2011 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see .
***/
#include
#include
#include
#include
#include
#include "systemd/sd-id128.h"
#include "systemd/sd-messages.h"
#include "strv.h"
#include "util.h"
#include "mkdir.h"
#include "path-util.h"
#include "cgroup-util.h"
#include "logind-session.h"
#define IDLE_THRESHOLD_USEC (5*USEC_PER_MINUTE)
Session* session_new(Manager *m, User *u, const char *id) {
Session *s;
assert(m);
assert(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->id = path_get_file_name(s->state_file);
if (hashmap_put(m->sessions, s->id, s) < 0) {
free(s->state_file);
free(s);
return NULL;
}
s->manager = m;
s->fifo_fd = -1;
s->user = u;
LIST_PREPEND(Session, sessions_by_user, u->sessions, s);
return s;
}
void session_free(Session *s) {
assert(s);
if (s->in_gc_queue)
LIST_REMOVE(Session, gc_queue, s->manager->session_gc_queue, s);
if (s->user) {
LIST_REMOVE(Session, 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;
LIST_REMOVE(Session, sessions_by_seat, s->seat->sessions, s);
}
if (s->cgroup_path)
hashmap_remove(s->manager->session_cgroups, s->cgroup_path);
free(s->cgroup_path);
strv_free(s->controllers);
free(s->tty);
free(s->display);
free(s->remote_host);
free(s->remote_user);
free(s->service);
hashmap_remove(s->manager->sessions, s->id);
session_remove_fifo(s);
free(s->state_file);
free(s);
}
int session_save(Session *s) {
FILE *f;
int r = 0;
char *temp_path;
assert(s);
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"
"KILL_PROCESSES=%i\n",
(unsigned long) s->user->uid,
s->user->name,
session_is_active(s),
session_state_to_string(session_get_state(s)),
s->remote,
s->kill_processes);
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->cgroup_path)
fprintf(f,
"CGROUP=%s\n",
s->cgroup_path);
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_can_multi_session(s->seat))
fprintf(f,
"VTNR=%i\n",
s->vtnr);
if (s->leader > 0)
fprintf(f,
"LEADER=%lu\n",
(unsigned long) s->leader);
if (s->audit_id > 0)
fprintf(f,
"AUDIT=%llu\n",
(unsigned long long) s->audit_id);
fflush(f);
if (ferror(f) || rename(temp_path, s->state_file) < 0) {
r = -errno;
unlink(s->state_file);
unlink(temp_path);
}
fclose(f);
free(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) {
char *remote = NULL,
*kill_processes = NULL,
*seat = NULL,
*vtnr = NULL,
*leader = NULL,
*audit_id = NULL,
*type = NULL,
*class = NULL;
int k, r;
assert(s);
r = parse_env_file(s->state_file, NEWLINE,
"REMOTE", &remote,
"KILL_PROCESSES", &kill_processes,
"CGROUP", &s->cgroup_path,
"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,
"LEADER", &leader,
"TYPE", &type,
"CLASS", &class,
NULL);
if (r < 0)
goto finish;
if (remote) {
k = parse_boolean(remote);
if (k >= 0)
s->remote = k;
}
if (kill_processes) {
k = parse_boolean(kill_processes);
if (k >= 0)
s->kill_processes = k;
}
if (seat && !s->seat) {
Seat *o;
o = hashmap_get(s->manager->seats, seat);
if (o)
seat_attach_session(o, s);
}
if (vtnr && s->seat && seat_can_multi_session(s->seat)) {
int v;
k = safe_atoi(vtnr, &v);
if (k >= 0 && v >= 1)
s->vtnr = v;
}
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
get an EOF. to trigger an EOF we hence open it for
reading, but close it right-away which then will
trigger the EOF. */
fd = session_create_fifo(s);
if (fd >= 0)
close_nointr_nofail(fd);
}
finish:
free(remote);
free(kill_processes);
free(seat);
free(vtnr);
free(leader);
free(audit_id);
free(class);
return r;
}
int session_activate(Session *s) {
int r;
assert(s);
if (s->vtnr < 0)
return -ENOTSUP;
if (!s->seat)
return -ENOTSUP;
if (s->seat->active == s)
return 0;
assert(seat_is_vtconsole(s->seat));
r = chvt(s->vtnr);
if (r < 0)
return r;
return seat_set_active(s->seat, s);
}
static int session_link_x11_socket(Session *s) {
char *t, *f, *c;
size_t k;
assert(s);
assert(s->user);
assert(s->user->runtime_path);
if (s->user->display)
return 0;
if (!s->display || !display_is_local(s->display))
return 0;
k = strspn(s->display+1, "0123456789");
f = new(char, sizeof("/tmp/.X11-unix/X") + k);
if (!f)
return log_oom();
c = stpcpy(f, "/tmp/.X11-unix/X");
memcpy(c, s->display+1, k);
c[k] = 0;
if (access(f, F_OK) < 0) {
log_warning("Session %s has display %s with non-existing socket %s.", s->id, s->display, f);
free(f);
return -ENOENT;
}
/* Note that this cannot be in a subdir to avoid
* vulnerabilities since we are privileged but the runtime
* path is owned by the user */
t = strappend(s->user->runtime_path, "/X11-display");
if (!t) {
free(f);
return log_oom();
}
if (link(f, t) < 0) {
if (errno == EEXIST) {
unlink(t);
if (link(f, t) >= 0)
goto done;
}
if (symlink(f, t) < 0) {
if (errno == EEXIST) {
unlink(t);
if (symlink(f, t) >= 0)
goto done;
}
log_error("Failed to link %s to %s: %m", f, t);
free(f);
free(t);
return -errno;
}
}
done:
log_info("Linked %s to %s.", f, t);
free(f);
free(t);
s->user->display = s;
return 0;
}
static int session_create_one_group(Session *s, const char *controller, const char *path) {
int r;
assert(s);
assert(controller);
assert(path);
if (s->leader > 0) {
r = cg_create_and_attach(controller, path, s->leader);
if (r < 0)
r = cg_create(controller, path);
} else
r = cg_create(controller, path);
if (r < 0)
return r;
r = cg_set_task_access(controller, path, 0644, s->user->uid, s->user->gid, -1);
if (r >= 0)
r = cg_set_group_access(controller, path, 0755, s->user->uid, s->user->gid);
return r;
}
static int session_create_cgroup(Session *s) {
char **k;
char *p;
int r;
assert(s);
assert(s->user);
assert(s->user->cgroup_path);
if (!s->cgroup_path) {
if (asprintf(&p, "%s/%s", s->user->cgroup_path, s->id) < 0)
return log_oom();
} else
p = s->cgroup_path;
r = session_create_one_group(s, SYSTEMD_CGROUP_CONTROLLER, p);
if (r < 0) {
log_error("Failed to create "SYSTEMD_CGROUP_CONTROLLER":%s: %s", p, strerror(-r));
free(p);
s->cgroup_path = NULL;
return r;
}
s->cgroup_path = p;
STRV_FOREACH(k, s->controllers) {
if (strv_contains(s->reset_controllers, *k))
continue;
r = session_create_one_group(s, *k, p);
if (r < 0)
log_warning("Failed to create %s:%s: %s", *k, p, strerror(-r));
}
STRV_FOREACH(k, s->manager->controllers) {
if (strv_contains(s->reset_controllers, *k) ||
strv_contains(s->manager->reset_controllers, *k) ||
strv_contains(s->controllers, *k))
continue;
r = session_create_one_group(s, *k, p);
if (r < 0)
log_warning("Failed to create %s:%s: %s", *k, p, strerror(-r));
}
if (s->leader > 0) {
STRV_FOREACH(k, s->reset_controllers) {
r = cg_attach(*k, "/", s->leader);
if (r < 0)
log_warning("Failed to reset controller %s: %s", *k, strerror(-r));
}
STRV_FOREACH(k, s->manager->reset_controllers) {
if (strv_contains(s->reset_controllers, *k) ||
strv_contains(s->controllers, *k))
continue;
r = cg_attach(*k, "/", s->leader);
if (r < 0)
log_warning("Failed to reset controller %s: %s", *k, strerror(-r));
}
}
hashmap_put(s->manager->session_cgroups, s->cgroup_path, s);
return 0;
}
int session_start(Session *s) {
int r;
assert(s);
assert(s->user);
if (s->started)
return 0;
r = user_start(s->user);
if (r < 0)
return r;
log_struct(s->type == SESSION_TTY || s->type == SESSION_X11 ? LOG_INFO : LOG_DEBUG,
"MESSAGE_ID=" SD_ID128_FORMAT_STR, SD_ID128_FORMAT_VAL(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);
/* Create cgroup */
r = session_create_cgroup(s);
if (r < 0)
return r;
/* Create X11 symlink */
session_link_x11_socket(s);
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\0ActiveSession\0");
else
seat_send_changed(s->seat, "Sessions\0");
}
user_send_changed(s->user, "Sessions\0");
return 0;
}
static bool session_shall_kill(Session *s) {
assert(s);
if (!s->kill_processes)
return false;
if (strv_contains(s->manager->kill_exclude_users, s->user->name))
return false;
if (strv_isempty(s->manager->kill_only_users))
return true;
return strv_contains(s->manager->kill_only_users, s->user->name);
}
static int session_terminate_cgroup(Session *s) {
int r;
char **k;
assert(s);
if (!s->cgroup_path)
return 0;
cg_trim(SYSTEMD_CGROUP_CONTROLLER, s->cgroup_path, false);
if (session_shall_kill(s)) {
r = cg_kill_recursive_and_wait(SYSTEMD_CGROUP_CONTROLLER, s->cgroup_path, true);
if (r < 0)
log_error("Failed to kill session cgroup: %s", strerror(-r));
} else {
if (s->leader > 0) {
Session *t;
/* We still send a HUP to the leader process,
* even if we are not supposed to kill the
* whole cgroup. But let's first check the
* leader still exists and belongs to our
* session... */
r = manager_get_session_by_pid(s->manager, s->leader, &t);
if (r > 0 && t == s) {
kill(s->leader, SIGTERM); /* for normal processes */
kill(s->leader, SIGHUP); /* for shells */
kill(s->leader, SIGCONT); /* in case they are stopped */
}
}
r = cg_is_empty_recursive(SYSTEMD_CGROUP_CONTROLLER, s->cgroup_path, true);
if (r < 0)
log_error("Failed to check session cgroup: %s", strerror(-r));
else if (r > 0) {
r = cg_delete(SYSTEMD_CGROUP_CONTROLLER, s->cgroup_path);
if (r < 0)
log_error("Failed to delete session cgroup: %s", strerror(-r));
}
}
STRV_FOREACH(k, s->user->manager->controllers)
cg_trim(*k, s->cgroup_path, true);
hashmap_remove(s->manager->session_cgroups, s->cgroup_path);
free(s->cgroup_path);
s->cgroup_path = NULL;
return 0;
}
static int session_unlink_x11_socket(Session *s) {
char *t;
int r;
assert(s);
assert(s->user);
if (s->user->display != s)
return 0;
s->user->display = NULL;
t = strappend(s->user->runtime_path, "/X11-display");
if (!t)
return log_oom();
r = unlink(t);
free(t);
return r < 0 ? -errno : 0;
}
int session_stop(Session *s) {
int r = 0, k;
assert(s);
if (s->started)
log_struct(s->type == SESSION_TTY || s->type == SESSION_X11 ? LOG_INFO : LOG_DEBUG,
"MESSAGE_ID=" SD_ID128_FORMAT_STR, SD_ID128_FORMAT_VAL(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 cgroup */
k = session_terminate_cgroup(s);
if (k < 0)
r = k;
/* Remove X11 symlink */
session_unlink_x11_socket(s);
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);
if (s->seat) {
if (s->seat->active == s)
seat_set_active(s->seat, NULL);
seat_send_changed(s->seat, "Sessions\0");
seat_save(s->seat);
}
user_send_changed(s->user, "Sessions\0");
user_save(s->user);
s->started = false;
return r;
}
bool session_is_active(Session *s) {
assert(s);
if (!s->seat)
return true;
return s->seat->active == s;
}
int session_get_idle_hint(Session *s, dual_timestamp *t) {
char *p;
struct stat st;
usec_t u, n;
bool b;
int k;
assert(s);
if (s->idle_hint) {
if (t)
*t = s->idle_hint_timestamp;
return s->idle_hint;
}
if (isempty(s->tty))
goto dont_know;
if (s->tty[0] != '/') {
p = strappend("/dev/", s->tty);
if (!p)
return -ENOMEM;
} else
p = NULL;
if (!startswith(p ? p : s->tty, "/dev/")) {
free(p);
goto dont_know;
}
k = lstat(p ? p : s->tty, &st);
free(p);
if (k < 0)
goto dont_know;
u = timespec_load(&st.st_atim);
n = now(CLOCK_REALTIME);
b = u + IDLE_THRESHOLD_USEC < n;
if (t)
dual_timestamp_from_realtime(t, u + b*IDLE_THRESHOLD_USEC);
return b;
dont_know:
if (t)
*t = s->idle_hint_timestamp;
return 0;
}
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\0"
"IdleSinceHint\0"
"IdleSinceHintMonotonic\0");
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");
}
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) {
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 (r < 0)
return r;
zero(ev);
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;
}
/* 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_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) {
unlink(s->fifo_path);
free(s->fifo_path);
s->fifo_path = NULL;
}
}
int session_check_gc(Session *s, bool drop_not_started) {
int r;
assert(s);
if (drop_not_started && !s->started)
return 0;
if (s->fifo_fd >= 0) {
r = pipe_eof(s->fifo_fd);
if (r < 0)
return r;
if (r == 0)
return 1;
}
if (s->cgroup_path) {
r = cg_is_empty_recursive(SYSTEMD_CGROUP_CONTROLLER, s->cgroup_path, false);
if (r < 0)
return r;
if (r <= 0)
return 1;
}
return 0;
}
void session_add_to_gc_queue(Session *s) {
assert(s);
if (s->in_gc_queue)
return;
LIST_PREPEND(Session, gc_queue, s->manager->session_gc_queue, s);
s->in_gc_queue = true;
}
SessionState session_get_state(Session *s) {
assert(s);
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) {
int r = 0;
Set *pid_set = NULL;
assert(s);
if (!s->cgroup_path)
return -ESRCH;
if (s->leader <= 0 && who == KILL_LEADER)
return -ESRCH;
if (s->leader > 0)
if (kill(s->leader, signo) < 0)
r = -errno;
if (who == KILL_ALL) {
int q;
pid_set = set_new(trivial_hash_func, trivial_compare_func);
if (!pid_set)
return -ENOMEM;
if (s->leader > 0) {
q = set_put(pid_set, LONG_TO_PTR(s->leader));
if (q < 0)
r = q;
}
q = cg_kill_recursive(SYSTEMD_CGROUP_CONTROLLER, s->cgroup_path, signo, false, true, false, pid_set);
if (q < 0)
if (q != -EAGAIN && q != -ESRCH && q != -ENOENT)
r = q;
}
if (pid_set)
set_free(pid_set);
return r;
}
static const char* const session_state_table[_SESSION_TYPE_MAX] = {
[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"
};
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);