src/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 General Public License as published by
  10   the Free Software Foundation; either version 2 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   General Public License for more details.
  17
  18   You should have received a copy of the GNU 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
  26 #include "logind-session.h"
  27 #include "strv.h"
  28 #include "util.h"
  29 #include "cgroup-util.h"
  30
  31 #define IDLE_THRESHOLD_USEC (5*USEC_PER_MINUTE)
  32
  33 Session* session_new(Manager *m, User *u, const char *id) {
  34         Session *s;
  35
  36         assert(m);
  37         assert(id);
  38
  39         s = new0(Session, 1);
  40         if (!s)
  41                 return NULL;
  42
  43         s->state_file = strappend("/run/systemd/sessions/", id);
  44         if (!s->state_file) {
  45                 free(s);
  46                 return NULL;
  47         }
  48
  49         s->id = file_name_from_path(s->state_file);
  50
  51         if (hashmap_put(m->sessions, s->id, s) < 0) {
  52                 free(s->id);
  53                 free(s);
  54                 return NULL;
  55         }
  56
  57         s->manager = m;
  58         s->pipe_fd = -1;
  59         s->user = u;
  60
  61         LIST_PREPEND(Session, sessions_by_user, u->sessions, s);
  62
  63         return s;
  64 }
  65
  66 void session_free(Session *s) {
  67         assert(s);
  68
  69         if (s->in_gc_queue)
  70                 LIST_REMOVE(Session, gc_queue, s->manager->session_gc_queue, s);
  71
  72         if (s->user) {
  73                 LIST_REMOVE(Session, sessions_by_user, s->user->sessions, s);
  74
  75                 if (s->user->display == s)
  76                         s->user->display = NULL;
  77         }
  78
  79         if (s->seat) {
  80                 if (s->seat->active == s)
  81                         s->seat->active = NULL;
  82
  83                 LIST_REMOVE(Session, sessions_by_seat, s->seat->sessions, s);
  84         }
  85
  86         if (s->cgroup_path)
  87                 hashmap_remove(s->manager->cgroups, s->cgroup_path);
  88
  89         free(s->cgroup_path);
  90         strv_free(s->controllers);
  91
  92         free(s->tty);
  93         free(s->display);
  94         free(s->remote_host);
  95         free(s->remote_user);
  96         free(s->service);
  97
  98         hashmap_remove(s->manager->sessions, s->id);
  99
 100         if (s->pipe_fd >= 0)
 101                 close_nointr_nofail(s->pipe_fd);
 102
 103         free(s->state_file);
 104         free(s);
 105 }
 106
 107 int session_save(Session *s) {
 108         FILE *f;
 109         int r = 0;
 110         char *temp_path;
 111
 112         assert(s);
 113
 114         r = safe_mkdir("/run/systemd/sessions", 0755, 0, 0);
 115         if (r < 0)
 116                 goto finish;
 117
 118         r = fopen_temporary(s->state_file, &f, &temp_path);
 119         if (r < 0)
 120                 goto finish;
 121
 122         assert(s->user);
 123
 124         fchmod(fileno(f), 0644);
 125
 126         fprintf(f,
 127                 "# This is private data. Do not parse.\n"
 128                 "UID=%lu\n"
 129                 "USER=%s\n"
 130                 "ACTIVE=%i\n"
 131                 "REMOTE=%i\n"
 132                 "KILL_PROCESSES=%i\n",
 133                 (unsigned long) s->user->uid,
 134                 s->user->name,
 135                 session_is_active(s),
 136                 s->remote,
 137                 s->kill_processes);
 138
 139         if (s->cgroup_path)
 140                 fprintf(f,
 141                         "CGROUP=%s\n",
 142                         s->cgroup_path);
 143
 144         if (s->seat)
 145                 fprintf(f,
 146                         "SEAT=%s\n",
 147                         s->seat->id);
 148
 149         if (s->tty)
 150                 fprintf(f,
 151                         "TTY=%s\n",
 152                         s->tty);
 153
 154         if (s->display)
 155                 fprintf(f,
 156                         "DISPLAY=%s\n",
 157                         s->display);
 158
 159         if (s->remote_host)
 160                 fprintf(f,
 161                         "REMOTE_HOST=%s\n",
 162                         s->remote_host);
 163
 164         if (s->remote_user)
 165                 fprintf(f,
 166                         "REMOTE_USER=%s\n",
 167                         s->remote_user);
 168
 169         if (s->service)
 170                 fprintf(f,
 171                         "SERVICE=%s\n",
 172                         s->service);
 173
 174         if (s->seat && seat_is_vtconsole(s->seat))
 175                 fprintf(f,
 176                         "VTNR=%i\n",
 177                         s->vtnr);
 178
 179         if (s->leader > 0)
 180                 fprintf(f,
 181                         "LEADER=%lu\n",
 182                         (unsigned long) s->leader);
 183
 184         if (s->audit_id > 0)
 185                 fprintf(f,
 186                         "AUDIT=%llu\n",
 187                         (unsigned long long) s->audit_id);
 188
 189         fflush(f);
 190
 191         if (ferror(f) || rename(temp_path, s->state_file) < 0) {
 192                 r = -errno;
 193                 unlink(s->state_file);
 194                 unlink(temp_path);
 195         }
 196
 197         fclose(f);
 198         free(temp_path);
 199
 200 finish:
 201         if (r < 0)
 202                 log_error("Failed to save session data for %s: %s", s->id, strerror(-r));
 203
 204         return r;
 205 }
 206
 207 int session_load(Session *s) {
 208         char *remote = NULL,
 209                 *kill_processes = NULL,
 210                 *seat = NULL,
 211                 *vtnr = NULL,
 212                 *leader = NULL,
 213                 *audit_id = NULL;
 214
 215         int k, r;
 216
 217         assert(s);
 218
 219         r = parse_env_file(s->state_file, NEWLINE,
 220                            "REMOTE",         &remote,
 221                            "KILL_PROCESSES", &kill_processes,
 222                            "CGROUP",         &s->cgroup_path,
 223                            "SEAT",           &seat,
 224                            "TTY",            &s->tty,
 225                            "DISPLAY",        &s->display,
 226                            "REMOTE_HOST",    &s->remote_host,
 227                            "REMOTE_USER",    &s->remote_user,
 228                            "SERVICE",        &s->service,
 229                            "VTNR",           &vtnr,
 230                            "LEADER",         &leader,
 231                            NULL);
 232
 233         if (r < 0)
 234                 goto finish;
 235
 236         if (remote) {
 237                 k = parse_boolean(remote);
 238                 if (k >= 0)
 239                         s->remote = k;
 240         }
 241
 242         if (kill_processes) {
 243                 k = parse_boolean(kill_processes);
 244                 if (k >= 0)
 245                         s->kill_processes = k;
 246         }
 247
 248         if (seat && !s->seat) {
 249                 Seat *o;
 250
 251                 o = hashmap_get(s->manager->seats, seat);
 252                 if (o)
 253                         seat_attach_session(o, s);
 254         }
 255
 256         if (vtnr && s->seat && seat_is_vtconsole(s->seat)) {
 257                 int v;
 258
 259                 k = safe_atoi(vtnr, &v);
 260                 if (k >= 0 && v >= 1)
 261                         s->vtnr = v;
 262         }
 263
 264         if (leader) {
 265                 pid_t pid;
 266
 267                 k = parse_pid(leader, &pid);
 268                 if (k >= 0 && pid >= 1) {
 269                         s->leader = pid;
 270
 271                         audit_session_from_pid(pid, &s->audit_id);
 272                 }
 273         }
 274
 275 finish:
 276         free(remote);
 277         free(kill_processes);
 278         free(seat);
 279         free(vtnr);
 280         free(leader);
 281         free(audit_id);
 282
 283         return r;
 284 }
 285
 286 int session_activate(Session *s) {
 287         int r;
 288         Session *old_active;
 289
 290         assert(s);
 291
 292         if (s->vtnr < 0)
 293                 return -ENOTSUP;
 294
 295         if (!s->seat)
 296                 return -ENOTSUP;
 297
 298         if (s->seat->active == s)
 299                 return 0;
 300
 301         assert(seat_is_vtconsole(s->seat));
 302
 303         r = chvt(s->vtnr);
 304         if (r < 0)
 305                 return r;
 306
 307         old_active = s->seat->active;
 308         s->seat->active = s;
 309
 310         return seat_apply_acls(s->seat, old_active);
 311 }
 312
 313 bool x11_display_is_local(const char *display) {
 314         assert(display);
 315
 316         return
 317                 display[0] == ':' &&
 318                 display[1] >= '0' &&
 319                 display[1] <= '9';
 320 }
 321
 322 static int session_link_x11_socket(Session *s) {
 323         char *t, *f, *c;
 324         size_t k;
 325
 326         assert(s);
 327         assert(s->user);
 328         assert(s->user->runtime_path);
 329
 330         if (s->user->display)
 331                 return 0;
 332
 333         if (!s->display || !x11_display_is_local(s->display))
 334                 return 0;
 335
 336         k = strspn(s->display+1, "0123456789");
 337         f = new(char, sizeof("/tmp/.X11-unix/X") + k);
 338         if (!f) {
 339                 log_error("Out of memory");
 340                 return -ENOMEM;
 341         }
 342
 343         c = stpcpy(f, "/tmp/.X11-unix/X");
 344         memcpy(c, s->display+1, k);
 345         c[k] = 0;
 346
 347         if (access(f, F_OK) < 0) {
 348                 log_warning("Session %s has display %s with nonexisting socket %s.", s->id, s->display, f);
 349                 free(f);
 350                 return -ENOENT;
 351         }
 352
 353         t = strappend(s->user->runtime_path, "/display");
 354         if (!t) {
 355                 log_error("Out of memory");
 356                 free(f);
 357                 return -ENOMEM;
 358         }
 359
 360         if (link(f, t) < 0) {
 361                 if (errno == EEXIST) {
 362                         unlink(t);
 363
 364                         if (link(f, t) >= 0)
 365                                 goto done;
 366                 }
 367
 368                 if (symlink(f, t) < 0) {
 369
 370                         if (errno == EEXIST) {
 371                                 unlink(t);
 372
 373                                 if (symlink(f, t) >= 0)
 374                                         goto done;
 375                         }
 376
 377                         log_error("Failed to link %s to %s: %m", f, t);
 378                         free(f);
 379                         free(t);
 380                         return -errno;
 381                 }
 382         }
 383
 384 done:
 385         log_info("Linked %s to %s.", f, t);
 386         free(f);
 387         free(t);
 388
 389         s->user->display = s;
 390
 391         return 0;
 392 }
 393
 394 static int session_create_one_group(Session *s, const char *controller, const char *path) {
 395         int r;
 396
 397         assert(s);
 398         assert(controller);
 399         assert(path);
 400
 401         if (s->leader > 0)
 402                 r = cg_create_and_attach(controller, path, s->leader);
 403         else
 404                 r = cg_create(controller, path);
 405
 406         if (r < 0)
 407                 return r;
 408
 409         r = cg_set_task_access(controller, path, 0644, s->user->uid, s->user->gid);
 410         if (r >= 0)
 411                 r = cg_set_group_access(controller, path, 0755, s->user->uid, s->user->gid);
 412
 413         return r;
 414 }
 415
 416 static int session_create_cgroup(Session *s) {
 417         char **k;
 418         char *p;
 419         int r;
 420
 421         assert(s);
 422         assert(s->user);
 423         assert(s->user->cgroup_path);
 424
 425         if (!s->cgroup_path) {
 426                 if (asprintf(&p, "%s/%s", s->user->cgroup_path, s->id) < 0) {
 427                         log_error("Out of memory");
 428                         return -ENOMEM;
 429                 }
 430         } else
 431                 p = s->cgroup_path;
 432
 433         r = session_create_one_group(s, SYSTEMD_CGROUP_CONTROLLER, p);
 434         if (r < 0) {
 435                 free(p);
 436                 s->cgroup_path = NULL;
 437                 log_error("Failed to create "SYSTEMD_CGROUP_CONTROLLER":%s: %s", p, strerror(-r));
 438                 return r;
 439         }
 440
 441         s->cgroup_path = p;
 442
 443         STRV_FOREACH(k, s->controllers) {
 444
 445                 if (strv_contains(s->reset_controllers, *k))
 446                         continue;
 447
 448                 r = session_create_one_group(s, *k, p);
 449                 if (r < 0)
 450                         log_warning("Failed to create %s:%s: %s", *k, p, strerror(-r));
 451         }
 452
 453         STRV_FOREACH(k, s->manager->controllers) {
 454
 455                 if (strv_contains(s->reset_controllers, *k) ||
 456                     strv_contains(s->controllers, *k))
 457                         continue;
 458
 459                 r = session_create_one_group(s, *k, p);
 460                 if (r < 0)
 461                         log_warning("Failed to create %s:%s: %s", *k, p, strerror(-r));
 462         }
 463
 464         if (s->leader > 0) {
 465
 466                 STRV_FOREACH(k, s->reset_controllers) {
 467                         r = cg_attach(*k, "/", s->leader);
 468                         if (r < 0)
 469                                 log_warning("Failed to reset controller %s: %s", *k, strerror(-r));
 470
 471                 }
 472         }
 473
 474         hashmap_put(s->manager->cgroups, s->cgroup_path, s);
 475
 476         return 0;
 477 }
 478
 479 int session_start(Session *s) {
 480         int r;
 481
 482         assert(s);
 483         assert(s->user);
 484
 485         if (s->started)
 486                 return 0;
 487
 488         r = user_start(s->user);
 489         if (r < 0)
 490                 return r;
 491
 492         log_info("New session %s of user %s.", s->id, s->user->name);
 493
 494         /* Create cgroup */
 495         r = session_create_cgroup(s);
 496         if (r < 0)
 497                 return r;
 498
 499         /* Create X11 symlink */
 500         session_link_x11_socket(s);
 501
 502         /* Save session data */
 503         session_save(s);
 504
 505         dual_timestamp_get(&s->timestamp);
 506
 507         s->started = true;
 508
 509         session_send_signal(s, true);
 510
 511         if (s->seat) {
 512                 if (s->seat->active == s)
 513                         seat_send_changed(s->seat, "Sessions\0ActiveSession\0");
 514                 else
 515                         seat_send_changed(s->seat, "Sessions\0");
 516         }
 517
 518         user_send_changed(s->user, "Sessions\0");
 519
 520         return 0;
 521 }
 522
 523 static bool session_shall_kill(Session *s) {
 524         assert(s);
 525
 526         if (!s->kill_processes)
 527                 return false;
 528
 529         if (strv_contains(s->manager->kill_exclude_users, s->user->name))
 530                 return false;
 531
 532         if (strv_isempty(s->manager->kill_only_users))
 533                 return true;
 534
 535         return strv_contains(s->manager->kill_only_users, s->user->name);
 536 }
 537
 538 static int session_kill_cgroup(Session *s) {
 539         int r;
 540         char **k;
 541
 542         assert(s);
 543
 544         if (!s->cgroup_path)
 545                 return 0;
 546
 547         cg_trim(SYSTEMD_CGROUP_CONTROLLER, s->cgroup_path, false);
 548
 549         if (session_shall_kill(s)) {
 550
 551                 r = cg_kill_recursive_and_wait(SYSTEMD_CGROUP_CONTROLLER, s->cgroup_path, true);
 552                 if (r < 0)
 553                         log_error("Failed to kill session cgroup: %s", strerror(-r));
 554
 555         } else {
 556                 r = cg_is_empty_recursive(SYSTEMD_CGROUP_CONTROLLER, s->cgroup_path, true);
 557                 if (r < 0)
 558                         log_error("Failed to check session cgroup: %s", strerror(-r));
 559                 else if (r > 0) {
 560                         r = cg_delete(SYSTEMD_CGROUP_CONTROLLER, s->cgroup_path);
 561                         if (r < 0)
 562                                 log_error("Failed to delete session cgroup: %s", strerror(-r));
 563                 } else
 564                         r = -EBUSY;
 565         }
 566
 567         STRV_FOREACH(k, s->user->manager->controllers)
 568                 cg_trim(*k, s->cgroup_path, true);
 569
 570         hashmap_remove(s->manager->cgroups, s->cgroup_path);
 571
 572         free(s->cgroup_path);
 573         s->cgroup_path = NULL;
 574
 575         return r;
 576 }
 577
 578 static int session_unlink_x11_socket(Session *s) {
 579         char *t;
 580         int r;
 581
 582         assert(s);
 583         assert(s->user);
 584
 585         if (s->user->display != s)
 586                 return 0;
 587
 588         s->user->display = NULL;
 589
 590         t = strappend(s->user->runtime_path, "/display");
 591         if (!t) {
 592                 log_error("Out of memory");
 593                 return -ENOMEM;
 594         }
 595
 596         r = unlink(t);
 597         free(t);
 598
 599         return r < 0 ? -errno : 0;
 600 }
 601
 602 int session_stop(Session *s) {
 603         int r = 0, k;
 604
 605         assert(s);
 606
 607         if (s->started)
 608                 log_info("Removed session %s.", s->id);
 609
 610         /* Kill cgroup */
 611         k = session_kill_cgroup(s);
 612         if (k < 0)
 613                 r = k;
 614
 615         /* Remove X11 symlink */
 616         session_unlink_x11_socket(s);
 617
 618         unlink(s->state_file);
 619         session_add_to_gc_queue(s);
 620         user_add_to_gc_queue(s->user);
 621
 622         if (s->started)
 623                 session_send_signal(s, false);
 624
 625         if (s->seat) {
 626                 if (s->seat->active == s)
 627                         seat_set_active(s->seat, NULL);
 628
 629                 seat_send_changed(s->seat, "Sessions\0");
 630         }
 631
 632         user_send_changed(s->user, "Sessions\0");
 633
 634         s->started = false;
 635
 636         return r;
 637 }
 638
 639 bool session_is_active(Session *s) {
 640         assert(s);
 641
 642         if (!s->seat)
 643                 return true;
 644
 645         return s->seat->active == s;
 646 }
 647
 648 int session_get_idle_hint(Session *s, dual_timestamp *t) {
 649         char *p;
 650         struct stat st;
 651         usec_t u, n;
 652         bool b;
 653         int k;
 654
 655         assert(s);
 656
 657         if (s->idle_hint) {
 658                 if (t)
 659                         *t = s->idle_hint_timestamp;
 660
 661                 return s->idle_hint;
 662         }
 663
 664         if (isempty(s->tty))
 665                 goto dont_know;
 666
 667         if (s->tty[0] != '/') {
 668                 p = strappend("/dev/", s->tty);
 669                 if (!p)
 670                         return -ENOMEM;
 671         } else
 672                 p = NULL;
 673
 674         if (!startswith(p ? p : s->tty, "/dev/")) {
 675                 free(p);
 676                 goto dont_know;
 677         }
 678
 679         k = lstat(p ? p : s->tty, &st);
 680         free(p);
 681
 682         if (k < 0)
 683                 goto dont_know;
 684
 685         u = timespec_load(&st.st_atim);
 686         n = now(CLOCK_REALTIME);
 687         b = u + IDLE_THRESHOLD_USEC < n;
 688
 689         if (t)
 690                 dual_timestamp_from_realtime(t, u + b ? IDLE_THRESHOLD_USEC : 0);
 691
 692         return b;
 693
 694 dont_know:
 695         if (t)
 696                 *t = s->idle_hint_timestamp;
 697
 698         return 0;
 699 }
 700
 701 void session_set_idle_hint(Session *s, bool b) {
 702         assert(s);
 703
 704         if (s->idle_hint == b)
 705                 return;
 706
 707         s->idle_hint = b;
 708         dual_timestamp_get(&s->idle_hint_timestamp);
 709
 710         session_send_changed(s,
 711                              "IdleHint\0"
 712                              "IdleSinceHint\0"
 713                              "IdleSinceHintMonotonic\0");
 714
 715         if (s->seat)
 716                 seat_send_changed(s->seat,
 717                                   "IdleHint\0"
 718                                   "IdleSinceHint\0"
 719                                   "IdleSinceHintMonotonic\0");
 720
 721         user_send_changed(s->user,
 722                           "IdleHint\0"
 723                           "IdleSinceHint\0"
 724                           "IdleSinceHintMonotonic\0");
 725
 726         manager_send_changed(s->manager,
 727                              "IdleHint\0"
 728                              "IdleSinceHint\0"
 729                              "IdleSinceHintMonotonic\0");
 730 }
 731
 732 int session_check_gc(Session *s) {
 733         int r;
 734
 735         assert(s);
 736
 737         if (s->pipe_fd >= 0) {
 738
 739                 r = pipe_eof(s->pipe_fd);
 740                 if (r < 0)
 741                         return r;
 742
 743                 if (r == 0)
 744                         return 1;
 745         }
 746
 747         if (s->cgroup_path) {
 748
 749                 r = cg_is_empty_recursive(SYSTEMD_CGROUP_CONTROLLER, s->cgroup_path, false);
 750                 if (r < 0)
 751                         return r;
 752
 753                 if (r <= 0)
 754                         return 1;
 755         }
 756
 757         return 0;
 758 }
 759
 760 void session_add_to_gc_queue(Session *s) {
 761         assert(s);
 762
 763         if (s->in_gc_queue)
 764                 return;
 765
 766         LIST_PREPEND(Session, gc_queue, s->manager->session_gc_queue, s);
 767         s->in_gc_queue = true;
 768 }
 769
 770 static const char* const session_type_table[_SESSION_TYPE_MAX] = {
 771         [SESSION_TTY] = "tty",
 772         [SESSION_X11] = "x11",
 773         [SESSION_OTHER] = "other"
 774 };
 775
 776 DEFINE_STRING_TABLE_LOOKUP(session_type, SessionType);