/*-*- 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);