src/login/logind-session.c

   1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
   2
   3 /***
   4   This file is part of systemd.
   5
   6   Copyright 2011 Lennart Poettering
   7
   8   systemd is free software; you can redistribute it and/or modify it
   9   under the terms of the GNU Lesser General Public License as published by
  10   the Free Software Foundation; either version 2.1 of the License, or
  11   (at your option) any later version.
  12
  13   systemd is distributed in the hope that it will be useful, but
  14   WITHOUT ANY WARRANTY; without even the implied warranty of
  15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16   Lesser General Public License for more details.
  17
  18   You should have received a copy of the GNU Lesser General Public License
  19   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  20 ***/
  21
  22 #include <errno.h>
  23 #include <string.h>
  24 #include <unistd.h>
  25 #include <sys/epoll.h>
  26 #include <fcntl.h>
  27
  28 #include "systemd/sd-id128.h"
  29 #include "systemd/sd-messages.h"
  30 #include "strv.h"
  31 #include "util.h"
  32 #include "mkdir.h"
  33 #include "path-util.h"
  34 #include "cgroup-util.h"
  35 #include "logind-session.h"
  36
  37 Session* session_new(Manager *m, User *u, const char *id) {
  38         Session *s;
  39
  40         assert(m);
  41         assert(id);
  42
  43         s = new0(Session, 1);
  44         if (!s)
  45                 return NULL;
  46
  47         s->state_file = strappend("/run/systemd/sessions/", id);
  48         if (!s->state_file) {
  49                 free(s);
  50                 return NULL;
  51         }
  52
  53         s->id = path_get_file_name(s->state_file);
  54
  55         if (hashmap_put(m->sessions, s->id, s) < 0) {
  56                 free(s->state_file);
  57                 free(s);
  58                 return NULL;
  59         }
  60
  61         s->manager = m;
  62         s->fifo_fd = -1;
  63         s->user = u;
  64
  65         LIST_PREPEND(Session, sessions_by_user, u->sessions, s);
  66
  67         return s;
  68 }
  69
  70 void session_free(Session *s) {
  71         assert(s);
  72
  73         if (s->in_gc_queue)
  74                 LIST_REMOVE(Session, gc_queue, s->manager->session_gc_queue, s);
  75
  76         if (s->user) {
  77                 LIST_REMOVE(Session, sessions_by_user, s->user->sessions, s);
  78
  79                 if (s->user->display == s)
  80                         s->user->display = NULL;
  81         }
  82
  83         if (s->seat) {
  84                 if (s->seat->active == s)
  85                         s->seat->active = NULL;
  86
  87                 LIST_REMOVE(Session, sessions_by_seat, s->seat->sessions, s);
  88         }
  89
  90         if (s->cgroup_path)
  91                 hashmap_remove(s->manager->session_cgroups, s->cgroup_path);
  92
  93         free(s->cgroup_path);
  94         strv_free(s->controllers);
  95
  96         free(s->tty);
  97         free(s->display);
  98         free(s->remote_host);
  99         free(s->remote_user);
 100         free(s->service);
 101
 102         hashmap_remove(s->manager->sessions, s->id);
 103         session_remove_fifo(s);
 104
 105         free(s->state_file);
 106         free(s);
 107 }
 108
 109 int session_save(Session *s) {
 110         FILE *f;
 111         int r = 0;
 112         char *temp_path;
 113
 114         assert(s);
 115
 116         if (!s->started)
 117                 return 0;
 118
 119         r = mkdir_safe_label("/run/systemd/sessions", 0755, 0, 0);
 120         if (r < 0)
 121                 goto finish;
 122
 123         r = fopen_temporary(s->state_file, &f, &temp_path);
 124         if (r < 0)
 125                 goto finish;
 126
 127         assert(s->user);
 128
 129         fchmod(fileno(f), 0644);
 130
 131         fprintf(f,
 132                 "# This is private data. Do not parse.\n"
 133                 "UID=%lu\n"
 134                 "USER=%s\n"
 135                 "ACTIVE=%i\n"
 136                 "STATE=%s\n"
 137                 "REMOTE=%i\n"
 138                 "KILL_PROCESSES=%i\n",
 139                 (unsigned long) s->user->uid,
 140                 s->user->name,
 141                 session_is_active(s),
 142                 session_state_to_string(session_get_state(s)),
 143                 s->remote,
 144                 s->kill_processes);
 145
 146         if (s->type >= 0)
 147                 fprintf(f,
 148                         "TYPE=%s\n",
 149                         session_type_to_string(s->type));
 150
 151         if (s->class >= 0)
 152                 fprintf(f,
 153                         "CLASS=%s\n",
 154                         session_class_to_string(s->class));
 155
 156         if (s->cgroup_path)
 157                 fprintf(f,
 158                         "CGROUP=%s\n",
 159                         s->cgroup_path);
 160
 161         if (s->fifo_path)
 162                 fprintf(f,
 163                         "FIFO=%s\n",
 164                         s->fifo_path);
 165
 166         if (s->seat)
 167                 fprintf(f,
 168                         "SEAT=%s\n",
 169                         s->seat->id);
 170
 171         if (s->tty)
 172                 fprintf(f,
 173                         "TTY=%s\n",
 174                         s->tty);
 175
 176         if (s->display)
 177                 fprintf(f,
 178                         "DISPLAY=%s\n",
 179                         s->display);
 180
 181         if (s->remote_host)
 182                 fprintf(f,
 183                         "REMOTE_HOST=%s\n",
 184                         s->remote_host);
 185
 186         if (s->remote_user)
 187                 fprintf(f,
 188                         "REMOTE_USER=%s\n",
 189                         s->remote_user);
 190
 191         if (s->service)
 192                 fprintf(f,
 193                         "SERVICE=%s\n",
 194                         s->service);
 195
 196         if (s->seat && seat_can_multi_session(s->seat))
 197                 fprintf(f,
 198                         "VTNR=%i\n",
 199                         s->vtnr);
 200
 201         if (s->leader > 0)
 202                 fprintf(f,
 203                         "LEADER=%lu\n",
 204                         (unsigned long) s->leader);
 205
 206         if (s->audit_id > 0)
 207                 fprintf(f,
 208                         "AUDIT=%llu\n",
 209                         (unsigned long long) s->audit_id);
 210
 211         fflush(f);
 212
 213         if (ferror(f) || rename(temp_path, s->state_file) < 0) {
 214                 r = -errno;
 215                 unlink(s->state_file);
 216                 unlink(temp_path);
 217         }
 218
 219         fclose(f);
 220         free(temp_path);
 221
 222 finish:
 223         if (r < 0)
 224                 log_error("Failed to save session data for %s: %s", s->id, strerror(-r));
 225
 226         return r;
 227 }
 228
 229 int session_load(Session *s) {
 230         char *remote = NULL,
 231                 *kill_processes = NULL,
 232                 *seat = NULL,
 233                 *vtnr = NULL,
 234                 *leader = NULL,
 235                 *audit_id = NULL,
 236                 *type = NULL,
 237                 *class = NULL;
 238
 239         int k, r;
 240
 241         assert(s);
 242
 243         r = parse_env_file(s->state_file, NEWLINE,
 244                            "REMOTE",         &remote,
 245                            "KILL_PROCESSES", &kill_processes,
 246                            "CGROUP",         &s->cgroup_path,
 247                            "FIFO",           &s->fifo_path,
 248                            "SEAT",           &seat,
 249                            "TTY",            &s->tty,
 250                            "DISPLAY",        &s->display,
 251                            "REMOTE_HOST",    &s->remote_host,
 252                            "REMOTE_USER",    &s->remote_user,
 253                            "SERVICE",        &s->service,
 254                            "VTNR",           &vtnr,
 255                            "LEADER",         &leader,
 256                            "TYPE",           &type,
 257                            "CLASS",          &class,
 258                            NULL);
 259
 260         if (r < 0)
 261                 goto finish;
 262
 263         if (remote) {
 264                 k = parse_boolean(remote);
 265                 if (k >= 0)
 266                         s->remote = k;
 267         }
 268
 269         if (kill_processes) {
 270                 k = parse_boolean(kill_processes);
 271                 if (k >= 0)
 272                         s->kill_processes = k;
 273         }
 274
 275         if (seat && !s->seat) {
 276                 Seat *o;
 277
 278                 o = hashmap_get(s->manager->seats, seat);
 279                 if (o)
 280                         seat_attach_session(o, s);
 281         }
 282
 283         if (vtnr && s->seat && seat_can_multi_session(s->seat)) {
 284                 int v;
 285
 286                 k = safe_atoi(vtnr, &v);
 287                 if (k >= 0 && v >= 1)
 288                         s->vtnr = v;
 289         }
 290
 291         if (leader) {
 292                 k = parse_pid(leader, &s->leader);
 293                 if (k >= 0)
 294                         audit_session_from_pid(s->leader, &s->audit_id);
 295         }
 296
 297         if (type) {
 298                 SessionType t;
 299
 300                 t = session_type_from_string(type);
 301                 if (t >= 0)
 302                         s->type = t;
 303         }
 304
 305         if (class) {
 306                 SessionClass c;
 307
 308                 c = session_class_from_string(class);
 309                 if (c >= 0)
 310                         s->class = c;
 311         }
 312
 313         if (s->fifo_path) {
 314                 int fd;
 315
 316                 /* If we open an unopened pipe for reading we will not
 317                    get an EOF. to trigger an EOF we hence open it for
 318                    reading, but close it right-away which then will
 319                    trigger the EOF. */
 320
 321                 fd = session_create_fifo(s);
 322                 if (fd >= 0)
 323                         close_nointr_nofail(fd);
 324         }
 325
 326 finish:
 327         free(remote);
 328         free(kill_processes);
 329         free(seat);
 330         free(vtnr);
 331         free(leader);
 332         free(audit_id);
 333         free(class);
 334
 335         return r;
 336 }
 337
 338 int session_activate(Session *s) {
 339         int r;
 340
 341         assert(s);
 342
 343         if (s->vtnr < 0)
 344                 return -ENOTSUP;
 345
 346         if (!s->seat)
 347                 return -ENOTSUP;
 348
 349         if (s->seat->active == s)
 350                 return 0;
 351
 352         assert(seat_is_vtconsole(s->seat));
 353
 354         r = chvt(s->vtnr);
 355         if (r < 0)
 356                 return r;
 357
 358         return seat_set_active(s->seat, s);
 359 }
 360
 361 static int session_link_x11_socket(Session *s) {
 362         char *t, *f, *c;
 363         size_t k;
 364
 365         assert(s);
 366         assert(s->user);
 367         assert(s->user->runtime_path);
 368
 369         if (s->user->display)
 370                 return 0;
 371
 372         if (!s->display || !display_is_local(s->display))
 373                 return 0;
 374
 375         k = strspn(s->display+1, "0123456789");
 376         f = new(char, sizeof("/tmp/.X11-unix/X") + k);
 377         if (!f)
 378                 return log_oom();
 379
 380         c = stpcpy(f, "/tmp/.X11-unix/X");
 381         memcpy(c, s->display+1, k);
 382         c[k] = 0;
 383
 384         if (access(f, F_OK) < 0) {
 385                 log_warning("Session %s has display %s with non-existing socket %s.", s->id, s->display, f);
 386                 free(f);
 387                 return -ENOENT;
 388         }
 389
 390         /* Note that this cannot be in a subdir to avoid
 391          * vulnerabilities since we are privileged but the runtime
 392          * path is owned by the user */
 393
 394         t = strappend(s->user->runtime_path, "/X11-display");
 395         if (!t) {
 396                 free(f);
 397                 return log_oom();
 398         }
 399
 400         if (link(f, t) < 0) {
 401                 if (errno == EEXIST) {
 402                         unlink(t);
 403
 404                         if (link(f, t) >= 0)
 405                                 goto done;
 406                 }
 407
 408                 if (symlink(f, t) < 0) {
 409
 410                         if (errno == EEXIST) {
 411                                 unlink(t);
 412
 413                                 if (symlink(f, t) >= 0)
 414                                         goto done;
 415                         }
 416
 417                         log_error("Failed to link %s to %s: %m", f, t);
 418                         free(f);
 419                         free(t);
 420                         return -errno;
 421                 }
 422         }
 423
 424 done:
 425         log_info("Linked %s to %s.", f, t);
 426         free(f);
 427         free(t);
 428
 429         s->user->display = s;
 430
 431         return 0;
 432 }
 433
 434 static int session_create_one_group(Session *s, const char *controller, const char *path) {
 435         int r;
 436
 437         assert(s);
 438         assert(controller);
 439         assert(path);
 440
 441         if (s->leader > 0) {
 442                 r = cg_create_and_attach(controller, path, s->leader);
 443                 if (r < 0)
 444                         r = cg_create(controller, path);
 445         } else
 446                 r = cg_create(controller, path);
 447
 448         if (r < 0)
 449                 return r;
 450
 451         r = cg_set_task_access(controller, path, 0644, s->user->uid, s->user->gid, -1);
 452         if (r >= 0)
 453                 r = cg_set_group_access(controller, path, 0755, s->user->uid, s->user->gid);
 454
 455         return r;
 456 }
 457
 458 static int session_create_cgroup(Session *s) {
 459         char **k;
 460         char *p;
 461         int r;
 462
 463         assert(s);
 464         assert(s->user);
 465         assert(s->user->cgroup_path);
 466
 467         if (!s->cgroup_path) {
 468                 if (asprintf(&p, "%s/%s", s->user->cgroup_path, s->id) < 0)
 469                         return log_oom();
 470         } else
 471                 p = s->cgroup_path;
 472
 473         r = session_create_one_group(s, SYSTEMD_CGROUP_CONTROLLER, p);
 474         if (r < 0) {
 475                 log_error("Failed to create "SYSTEMD_CGROUP_CONTROLLER":%s: %s", p, strerror(-r));
 476                 free(p);
 477                 s->cgroup_path = NULL;
 478                 return r;
 479         }
 480
 481         s->cgroup_path = p;
 482
 483         STRV_FOREACH(k, s->controllers) {
 484
 485                 if (strv_contains(s->reset_controllers, *k))
 486                         continue;
 487
 488                 r = session_create_one_group(s, *k, p);
 489                 if (r < 0)
 490                         log_warning("Failed to create %s:%s: %s", *k, p, strerror(-r));
 491         }
 492
 493         STRV_FOREACH(k, s->manager->controllers) {
 494
 495                 if (strv_contains(s->reset_controllers, *k) ||
 496                     strv_contains(s->manager->reset_controllers, *k) ||
 497                     strv_contains(s->controllers, *k))
 498                         continue;
 499
 500                 r = session_create_one_group(s, *k, p);
 501                 if (r < 0)
 502                         log_warning("Failed to create %s:%s: %s", *k, p, strerror(-r));
 503         }
 504
 505         if (s->leader > 0) {
 506
 507                 STRV_FOREACH(k, s->reset_controllers) {
 508                         r = cg_attach(*k, "/", s->leader);
 509                         if (r < 0)
 510                                 log_warning("Failed to reset controller %s: %s", *k, strerror(-r));
 511
 512                 }
 513
 514                 STRV_FOREACH(k, s->manager->reset_controllers) {
 515
 516                         if (strv_contains(s->reset_controllers, *k) ||
 517                             strv_contains(s->controllers, *k))
 518                                 continue;
 519
 520                         r = cg_attach(*k, "/", s->leader);
 521                         if (r < 0)
 522                                 log_warning("Failed to reset controller %s: %s", *k, strerror(-r));
 523
 524                 }
 525         }
 526
 527         r = hashmap_put(s->manager->session_cgroups, s->cgroup_path, s);
 528         if (r < 0)
 529                 log_warning("Failed to create mapping between cgroup and session");
 530
 531         return 0;
 532 }
 533
 534 int session_start(Session *s) {
 535         int r;
 536
 537         assert(s);
 538         assert(s->user);
 539
 540         if (s->started)
 541                 return 0;
 542
 543         r = user_start(s->user);
 544         if (r < 0)
 545                 return r;
 546
 547         log_struct(s->type == SESSION_TTY || s->type == SESSION_X11 ? LOG_INFO : LOG_DEBUG,
 548                    MESSAGE_ID(SD_MESSAGE_SESSION_START),
 549                    "SESSION_ID=%s", s->id,
 550                    "USER_ID=%s", s->user->name,
 551                    "LEADER=%lu", (unsigned long) s->leader,
 552                    "MESSAGE=New session %s of user %s.", s->id, s->user->name,
 553                    NULL);
 554
 555         /* Create cgroup */
 556         r = session_create_cgroup(s);
 557         if (r < 0)
 558                 return r;
 559
 560         /* Create X11 symlink */
 561         session_link_x11_socket(s);
 562
 563         dual_timestamp_get(&s->timestamp);
 564
 565         if (s->seat)
 566                 seat_read_active_vt(s->seat);
 567
 568         s->started = true;
 569
 570         /* Save session data */
 571         session_save(s);
 572         user_save(s->user);
 573
 574         session_send_signal(s, true);
 575
 576         if (s->seat) {
 577                 seat_save(s->seat);
 578
 579                 if (s->seat->active == s)
 580                         seat_send_changed(s->seat, "Sessions\0ActiveSession\0");
 581                 else
 582                         seat_send_changed(s->seat, "Sessions\0");
 583         }
 584
 585         user_send_changed(s->user, "Sessions\0");
 586
 587         return 0;
 588 }
 589
 590 static bool session_shall_kill(Session *s) {
 591         assert(s);
 592
 593         if (!s->kill_processes)
 594                 return false;
 595
 596         if (strv_contains(s->manager->kill_exclude_users, s->user->name))
 597                 return false;
 598
 599         if (strv_isempty(s->manager->kill_only_users))
 600                 return true;
 601
 602         return strv_contains(s->manager->kill_only_users, s->user->name);
 603 }
 604
 605 static int session_terminate_cgroup(Session *s) {
 606         int r;
 607         char **k;
 608
 609         assert(s);
 610
 611         if (!s->cgroup_path)
 612                 return 0;
 613
 614         cg_trim(SYSTEMD_CGROUP_CONTROLLER, s->cgroup_path, false);
 615
 616         if (session_shall_kill(s)) {
 617
 618                 r = cg_kill_recursive_and_wait(SYSTEMD_CGROUP_CONTROLLER, s->cgroup_path, true);
 619                 if (r < 0)
 620                         log_error("Failed to kill session cgroup: %s", strerror(-r));
 621
 622         } else {
 623                 if (s->leader > 0) {
 624                         Session *t;
 625
 626                         /* We still send a HUP to the leader process,
 627                          * even if we are not supposed to kill the
 628                          * whole cgroup. But let's first check the
 629                          * leader still exists and belongs to our
 630                          * session... */
 631
 632                         r = manager_get_session_by_pid(s->manager, s->leader, &t);
 633                         if (r > 0 && t == s) {
 634                                 kill(s->leader, SIGTERM); /* for normal processes */
 635                                 kill(s->leader, SIGHUP);  /* for shells */
 636                                 kill(s->leader, SIGCONT); /* in case they are stopped */
 637                         }
 638                 }
 639
 640                 r = cg_is_empty_recursive(SYSTEMD_CGROUP_CONTROLLER, s->cgroup_path, true);
 641                 if (r < 0)
 642                         log_error("Failed to check session cgroup: %s", strerror(-r));
 643                 else if (r > 0) {
 644                         r = cg_delete(SYSTEMD_CGROUP_CONTROLLER, s->cgroup_path);
 645                         if (r < 0)
 646                                 log_error("Failed to delete session cgroup: %s", strerror(-r));
 647                 }
 648         }
 649
 650         STRV_FOREACH(k, s->user->manager->controllers)
 651                 cg_trim(*k, s->cgroup_path, true);
 652
 653         hashmap_remove(s->manager->session_cgroups, s->cgroup_path);
 654
 655         free(s->cgroup_path);
 656         s->cgroup_path = NULL;
 657
 658         return 0;
 659 }
 660
 661 static int session_unlink_x11_socket(Session *s) {
 662         char *t;
 663         int r;
 664
 665         assert(s);
 666         assert(s->user);
 667
 668         if (s->user->display != s)
 669                 return 0;
 670
 671         s->user->display = NULL;
 672
 673         t = strappend(s->user->runtime_path, "/X11-display");
 674         if (!t)
 675                 return log_oom();
 676
 677         r = unlink(t);
 678         free(t);
 679
 680         return r < 0 ? -errno : 0;
 681 }
 682
 683 int session_stop(Session *s) {
 684         int r = 0, k;
 685
 686         assert(s);
 687
 688         if (s->started)
 689                 log_struct(s->type == SESSION_TTY || s->type == SESSION_X11 ? LOG_INFO : LOG_DEBUG,
 690                            MESSAGE_ID(SD_MESSAGE_SESSION_STOP),
 691                            "SESSION_ID=%s", s->id,
 692                            "USER_ID=%s", s->user->name,
 693                            "LEADER=%lu", (unsigned long) s->leader,
 694                            "MESSAGE=Removed session %s.", s->id,
 695                            NULL);
 696
 697         /* Kill cgroup */
 698         k = session_terminate_cgroup(s);
 699         if (k < 0)
 700                 r = k;
 701
 702         /* Remove X11 symlink */
 703         session_unlink_x11_socket(s);
 704
 705         unlink(s->state_file);
 706         session_add_to_gc_queue(s);
 707         user_add_to_gc_queue(s->user);
 708
 709         if (s->started)
 710                 session_send_signal(s, false);
 711
 712         if (s->seat) {
 713                 if (s->seat->active == s)
 714                         seat_set_active(s->seat, NULL);
 715
 716                 seat_send_changed(s->seat, "Sessions\0");
 717                 seat_save(s->seat);
 718         }
 719
 720         user_send_changed(s->user, "Sessions\0");
 721         user_save(s->user);
 722
 723         s->started = false;
 724
 725         return r;
 726 }
 727
 728 bool session_is_active(Session *s) {
 729         assert(s);
 730
 731         if (!s->seat)
 732                 return true;
 733
 734         return s->seat->active == s;
 735 }
 736
 737 static int get_tty_atime(const char *tty, usec_t *atime) {
 738         _cleanup_free_ char *p = NULL;
 739         struct stat st;
 740
 741         assert(tty);
 742         assert(atime);
 743
 744         if (!path_is_absolute(tty)) {
 745                 p = strappend("/dev/", tty);
 746                 if (!p)
 747                         return -ENOMEM;
 748
 749                 tty = p;
 750         } else if (!path_startswith(tty, "/dev/"))
 751                 return -ENOENT;
 752
 753         if (lstat(tty, &st) < 0)
 754                 return -errno;
 755
 756         *atime = timespec_load(&st.st_atim);
 757         return 0;
 758 }
 759
 760 static int get_process_ctty_atime(pid_t pid, usec_t *atime) {
 761         _cleanup_free_ char *p = NULL;
 762         int r;
 763
 764         assert(pid > 0);
 765         assert(atime);
 766
 767         r = get_ctty(pid, NULL, &p);
 768         if (r < 0)
 769                 return r;
 770
 771         return get_tty_atime(p, atime);
 772 }
 773
 774 int session_get_idle_hint(Session *s, dual_timestamp *t) {
 775         _cleanup_free_ char *p = NULL;
 776         usec_t atime = 0, n;
 777         int r;
 778
 779         assert(s);
 780
 781         /* Explicit idle hint is set */
 782         if (s->idle_hint) {
 783                 if (t)
 784                         *t = s->idle_hint_timestamp;
 785
 786                 return s->idle_hint;
 787         }
 788
 789         /* Graphical sessions really should really implement a real
 790          * idle hint logic */
 791         if (s->display)
 792                 goto dont_know;
 793
 794         /* For sessions with an explicitly configured tty, let's check
 795          * its atime */
 796         if (s->tty) {
 797                 r = get_tty_atime(s->tty, &atime);
 798                 if (r >= 0)
 799                         goto found_atime;
 800         }
 801
 802         /* For sessions with a leader but no explicitly configured
 803          * tty, let's check the controlling tty of the leader */
 804         if (s->leader > 0) {
 805                 r = get_process_ctty_atime(s->leader, &atime);
 806                 if (r >= 0)
 807                         goto found_atime;
 808         }
 809
 810         /* For other TTY sessions, let's find the most recent atime of
 811          * the ttys of any of the processes of the session */
 812         if (s->cgroup_path) {
 813                 _cleanup_fclose_ FILE *f = NULL;
 814
 815                 if (cg_enumerate_processes(SYSTEMD_CGROUP_CONTROLLER, s->cgroup_path, &f) >= 0) {
 816                         pid_t pid;
 817
 818                         atime = 0;
 819                         while (cg_read_pid(f, &pid) > 0) {
 820                                 usec_t a;
 821
 822                                 if (get_process_ctty_atime(pid, &a) >= 0)
 823                                         if (atime == 0 || atime < a)
 824                                                 atime = a;
 825                         }
 826
 827                         if (atime != 0)
 828                                 goto found_atime;
 829                 }
 830         }
 831
 832 dont_know:
 833         if (t)
 834                 *t = s->idle_hint_timestamp;
 835
 836         return 0;
 837
 838 found_atime:
 839         if (t)
 840                 dual_timestamp_from_realtime(t, atime);
 841
 842         n = now(CLOCK_REALTIME);
 843
 844         if (s->manager->idle_action_usec <= 0)
 845                 return 0;
 846
 847         return atime + s->manager->idle_action_usec <= n;
 848 }
 849
 850 void session_set_idle_hint(Session *s, bool b) {
 851         assert(s);
 852
 853         if (s->idle_hint == b)
 854                 return;
 855
 856         s->idle_hint = b;
 857         dual_timestamp_get(&s->idle_hint_timestamp);
 858
 859         session_send_changed(s,
 860                              "IdleHint\0"
 861                              "IdleSinceHint\0"
 862                              "IdleSinceHintMonotonic\0");
 863
 864         if (s->seat)
 865                 seat_send_changed(s->seat,
 866                                   "IdleHint\0"
 867                                   "IdleSinceHint\0"
 868                                   "IdleSinceHintMonotonic\0");
 869
 870         user_send_changed(s->user,
 871                           "IdleHint\0"
 872                           "IdleSinceHint\0"
 873                           "IdleSinceHintMonotonic\0");
 874
 875         manager_send_changed(s->manager,
 876                              "IdleHint\0"
 877                              "IdleSinceHint\0"
 878                              "IdleSinceHintMonotonic\0");
 879 }
 880
 881 int session_create_fifo(Session *s) {
 882         int r;
 883
 884         assert(s);
 885
 886         /* Create FIFO */
 887         if (!s->fifo_path) {
 888                 r = mkdir_safe_label("/run/systemd/sessions", 0755, 0, 0);
 889                 if (r < 0)
 890                         return r;
 891
 892                 if (asprintf(&s->fifo_path, "/run/systemd/sessions/%s.ref", s->id) < 0)
 893                         return -ENOMEM;
 894
 895                 if (mkfifo(s->fifo_path, 0600) < 0 && errno != EEXIST)
 896                         return -errno;
 897         }
 898
 899         /* Open reading side */
 900         if (s->fifo_fd < 0) {
 901                 struct epoll_event ev;
 902
 903                 s->fifo_fd = open(s->fifo_path, O_RDONLY|O_CLOEXEC|O_NDELAY);
 904                 if (s->fifo_fd < 0)
 905                         return -errno;
 906
 907                 r = hashmap_put(s->manager->session_fds, INT_TO_PTR(s->fifo_fd + 1), s);
 908                 if (r < 0)
 909                         return r;
 910
 911                 zero(ev);
 912                 ev.events = 0;
 913                 ev.data.u32 = FD_OTHER_BASE + s->fifo_fd;
 914
 915                 if (epoll_ctl(s->manager->epoll_fd, EPOLL_CTL_ADD, s->fifo_fd, &ev) < 0)
 916                         return -errno;
 917         }
 918
 919         /* Open writing side */
 920         r = open(s->fifo_path, O_WRONLY|O_CLOEXEC|O_NDELAY);
 921         if (r < 0)
 922                 return -errno;
 923
 924         return r;
 925 }
 926
 927 void session_remove_fifo(Session *s) {
 928         assert(s);
 929
 930         if (s->fifo_fd >= 0) {
 931                 assert_se(hashmap_remove(s->manager->session_fds, INT_TO_PTR(s->fifo_fd + 1)) == s);
 932                 assert_se(epoll_ctl(s->manager->epoll_fd, EPOLL_CTL_DEL, s->fifo_fd, NULL) == 0);
 933                 close_nointr_nofail(s->fifo_fd);
 934                 s->fifo_fd = -1;
 935
 936                 session_save(s);
 937                 user_save(s->user);
 938         }
 939
 940         if (s->fifo_path) {
 941                 unlink(s->fifo_path);
 942                 free(s->fifo_path);
 943                 s->fifo_path = NULL;
 944         }
 945 }
 946
 947 int session_check_gc(Session *s, bool drop_not_started) {
 948         int r;
 949
 950         assert(s);
 951
 952         if (drop_not_started && !s->started)
 953                 return 0;
 954
 955         if (s->fifo_fd >= 0) {
 956
 957                 r = pipe_eof(s->fifo_fd);
 958                 if (r < 0)
 959                         return r;
 960
 961                 if (r == 0)
 962                         return 1;
 963         }
 964
 965         if (s->cgroup_path) {
 966
 967                 r = cg_is_empty_recursive(SYSTEMD_CGROUP_CONTROLLER, s->cgroup_path, false);
 968                 if (r < 0)
 969                         return r;
 970
 971                 if (r <= 0)
 972                         return 1;
 973         }
 974
 975         return 0;
 976 }
 977
 978 void session_add_to_gc_queue(Session *s) {
 979         assert(s);
 980
 981         if (s->in_gc_queue)
 982                 return;
 983
 984         LIST_PREPEND(Session, gc_queue, s->manager->session_gc_queue, s);
 985         s->in_gc_queue = true;
 986 }
 987
 988 SessionState session_get_state(Session *s) {
 989         assert(s);
 990
 991         if (s->fifo_fd < 0)
 992                 return SESSION_CLOSING;
 993
 994         if (session_is_active(s))
 995                 return SESSION_ACTIVE;
 996
 997         return SESSION_ONLINE;
 998 }
 999
1000 int session_kill(Session *s, KillWho who, int signo) {
1001         int r = 0;
1002         Set *pid_set = NULL;
1003
1004         assert(s);
1005
1006         if (!s->cgroup_path)
1007                 return -ESRCH;
1008
1009         if (s->leader <= 0 && who == KILL_LEADER)
1010                 return -ESRCH;
1011
1012         if (s->leader > 0)
1013                 if (kill(s->leader, signo) < 0)
1014                         r = -errno;
1015
1016         if (who == KILL_ALL) {
1017                 int q;
1018
1019                 pid_set = set_new(trivial_hash_func, trivial_compare_func);
1020                 if (!pid_set)
1021                         return -ENOMEM;
1022
1023                 if (s->leader > 0) {
1024                         q = set_put(pid_set, LONG_TO_PTR(s->leader));
1025                         if (q < 0)
1026                                 r = q;
1027                 }
1028
1029                 q = cg_kill_recursive(SYSTEMD_CGROUP_CONTROLLER, s->cgroup_path, signo, false, true, false, pid_set);
1030                 if (q < 0)
1031                         if (q != -EAGAIN && q != -ESRCH && q != -ENOENT)
1032                                 r = q;
1033         }
1034
1035         if (pid_set)
1036                 set_free(pid_set);
1037
1038         return r;
1039 }
1040
1041 static const char* const session_state_table[_SESSION_TYPE_MAX] = {
1042         [SESSION_ONLINE] = "online",
1043         [SESSION_ACTIVE] = "active",
1044         [SESSION_CLOSING] = "closing"
1045 };
1046
1047 DEFINE_STRING_TABLE_LOOKUP(session_state, SessionState);
1048
1049 static const char* const session_type_table[_SESSION_TYPE_MAX] = {
1050         [SESSION_TTY] = "tty",
1051         [SESSION_X11] = "x11",
1052         [SESSION_UNSPECIFIED] = "unspecified"
1053 };
1054
1055 DEFINE_STRING_TABLE_LOOKUP(session_type, SessionType);
1056
1057 static const char* const session_class_table[_SESSION_CLASS_MAX] = {
1058         [SESSION_USER] = "user",
1059         [SESSION_GREETER] = "greeter",
1060         [SESSION_LOCK_SCREEN] = "lock-screen"
1061 };
1062
1063 DEFINE_STRING_TABLE_LOOKUP(session_class, SessionClass);
1064
1065 static const char* const kill_who_table[_KILL_WHO_MAX] = {
1066         [KILL_LEADER] = "leader",
1067         [KILL_ALL] = "all"
1068 };
1069
1070 DEFINE_STRING_TABLE_LOOKUP(kill_who, KillWho);