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 #include <sys/epoll.h>
  26
  27 #include "logind-session.h"
  28 #include "strv.h"
  29 #include "util.h"
  30 #include "cgroup-util.h"
  31
  32 #define IDLE_THRESHOLD_USEC (5*USEC_PER_MINUTE)
  33
  34 Session* session_new(Manager *m, User *u, const char *id) {
  35         Session *s;
  36
  37         assert(m);
  38         assert(id);
  39
  40         s = new0(Session, 1);
  41         if (!s)
  42                 return NULL;
  43
  44         s->state_file = strappend("/run/systemd/sessions/", id);
  45         if (!s->state_file) {
  46                 free(s);
  47                 return NULL;
  48         }
  49
  50         s->id = file_name_from_path(s->state_file);
  51
  52         if (hashmap_put(m->sessions, s->id, s) < 0) {
  53                 free(s->id);
  54                 free(s);
  55                 return NULL;
  56         }
  57
  58         s->manager = m;
  59         s->pipe_fd = -1;
  60         s->user = u;
  61
  62         LIST_PREPEND(Session, sessions_by_user, u->sessions, s);
  63
  64         return s;
  65 }
  66
  67 void session_free(Session *s) {
  68         assert(s);
  69
  70         if (s->in_gc_queue)
  71                 LIST_REMOVE(Session, gc_queue, s->manager->session_gc_queue, s);
  72
  73         if (s->user) {
  74                 LIST_REMOVE(Session, sessions_by_user, s->user->sessions, s);
  75
  76                 if (s->user->display == s)
  77                         s->user->display = NULL;
  78         }
  79
  80         if (s->seat) {
  81                 if (s->seat->active == s)
  82                         s->seat->active = NULL;
  83
  84                 LIST_REMOVE(Session, sessions_by_seat, s->seat->sessions, s);
  85         }
  86
  87         if (s->cgroup_path)
  88                 hashmap_remove(s->manager->cgroups, s->cgroup_path);
  89
  90         free(s->cgroup_path);
  91         strv_free(s->controllers);
  92
  93         free(s->tty);
  94         free(s->display);
  95         free(s->remote_host);
  96         free(s->remote_user);
  97         free(s->service);
  98
  99         hashmap_remove(s->manager->sessions, s->id);
 100
 101         session_unset_pipe_fd(s);
 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->type >= 0)
 140                 fprintf(f,
 141                         "TYPE=%s\n",
 142                         session_type_to_string(s->type));
 143
 144         if (s->cgroup_path)
 145                 fprintf(f,
 146                         "CGROUP=%s\n",
 147                         s->cgroup_path);
 148
 149         if (s->seat)
 150                 fprintf(f,
 151                         "SEAT=%s\n",
 152                         s->seat->id);
 153
 154         if (s->tty)
 155                 fprintf(f,
 156                         "TTY=%s\n",
 157                         s->tty);
 158
 159         if (s->display)
 160                 fprintf(f,
 161                         "DISPLAY=%s\n",
 162                         s->display);
 163
 164         if (s->remote_host)
 165                 fprintf(f,
 166                         "REMOTE_HOST=%s\n",
 167                         s->remote_host);
 168
 169         if (s->remote_user)
 170                 fprintf(f,
 171                         "REMOTE_USER=%s\n",
 172                         s->remote_user);
 173
 174         if (s->service)
 175                 fprintf(f,
 176                         "SERVICE=%s\n",
 177                         s->service);
 178
 179         if (s->seat && seat_is_vtconsole(s->seat))
 180                 fprintf(f,
 181                         "VTNR=%i\n",
 182                         s->vtnr);
 183
 184         if (s->leader > 0)
 185                 fprintf(f,
 186                         "LEADER=%lu\n",
 187                         (unsigned long) s->leader);
 188
 189         if (s->audit_id > 0)
 190                 fprintf(f,
 191                         "AUDIT=%llu\n",
 192                         (unsigned long long) s->audit_id);
 193
 194         fflush(f);
 195
 196         if (ferror(f) || rename(temp_path, s->state_file) < 0) {
 197                 r = -errno;
 198                 unlink(s->state_file);
 199                 unlink(temp_path);
 200         }
 201
 202         fclose(f);
 203         free(temp_path);
 204
 205 finish:
 206         if (r < 0)
 207                 log_error("Failed to save session data for %s: %s", s->id, strerror(-r));
 208
 209         return r;
 210 }
 211
 212 int session_load(Session *s) {
 213         char *remote = NULL,
 214                 *kill_processes = NULL,
 215                 *seat = NULL,
 216                 *vtnr = NULL,
 217                 *leader = NULL,
 218                 *audit_id = NULL,
 219                 *type = NULL;
 220
 221         int k, r;
 222
 223         assert(s);
 224
 225         r = parse_env_file(s->state_file, NEWLINE,
 226                            "REMOTE",         &remote,
 227                            "KILL_PROCESSES", &kill_processes,
 228                            "CGROUP",         &s->cgroup_path,
 229                            "SEAT",           &seat,
 230                            "TTY",            &s->tty,
 231                            "DISPLAY",        &s->display,
 232                            "REMOTE_HOST",    &s->remote_host,
 233                            "REMOTE_USER",    &s->remote_user,
 234                            "SERVICE",        &s->service,
 235                            "VTNR",           &vtnr,
 236                            "LEADER",         &leader,
 237                            "TYPE",           &type,
 238                            NULL);
 239
 240         if (r < 0)
 241                 goto finish;
 242
 243         if (remote) {
 244                 k = parse_boolean(remote);
 245                 if (k >= 0)
 246                         s->remote = k;
 247         }
 248
 249         if (kill_processes) {
 250                 k = parse_boolean(kill_processes);
 251                 if (k >= 0)
 252                         s->kill_processes = k;
 253         }
 254
 255         if (seat && !s->seat) {
 256                 Seat *o;
 257
 258                 o = hashmap_get(s->manager->seats, seat);
 259                 if (o)
 260                         seat_attach_session(o, s);
 261         }
 262
 263         if (vtnr && s->seat && seat_is_vtconsole(s->seat)) {
 264                 int v;
 265
 266                 k = safe_atoi(vtnr, &v);
 267                 if (k >= 0 && v >= 1)
 268                         s->vtnr = v;
 269         }
 270
 271         if (leader) {
 272                 pid_t pid;
 273
 274                 k = parse_pid(leader, &pid);
 275                 if (k >= 0 && pid >= 1) {
 276                         s->leader = pid;
 277
 278                         audit_session_from_pid(pid, &s->audit_id);
 279                 }
 280         }
 281
 282         if (type) {
 283                 SessionType t;
 284
 285                 t = session_type_from_string(type);
 286                 if (t >= 0)
 287                         s->type = t;
 288         }
 289
 290 finish:
 291         free(remote);
 292         free(kill_processes);
 293         free(seat);
 294         free(vtnr);
 295         free(leader);
 296         free(audit_id);
 297
 298         return r;
 299 }
 300
 301 int session_activate(Session *s) {
 302         int r;
 303         Session *old_active;
 304
 305         assert(s);
 306
 307         if (s->vtnr < 0)
 308                 return -ENOTSUP;
 309
 310         if (!s->seat)
 311                 return -ENOTSUP;
 312
 313         if (s->seat->active == s)
 314                 return 0;
 315
 316         assert(seat_is_vtconsole(s->seat));
 317
 318         r = chvt(s->vtnr);
 319         if (r < 0)
 320                 return r;
 321
 322         old_active = s->seat->active;
 323         s->seat->active = s;
 324
 325         return seat_apply_acls(s->seat, old_active);
 326 }
 327
 328 bool x11_display_is_local(const char *display) {
 329         assert(display);
 330
 331         return
 332                 display[0] == ':' &&
 333                 display[1] >= '0' &&
 334                 display[1] <= '9';
 335 }
 336
 337 static int session_link_x11_socket(Session *s) {
 338         char *t, *f, *c;
 339         size_t k;
 340
 341         assert(s);
 342         assert(s->user);
 343         assert(s->user->runtime_path);
 344
 345         if (s->user->display)
 346                 return 0;
 347
 348         if (!s->display || !x11_display_is_local(s->display))
 349                 return 0;
 350
 351         k = strspn(s->display+1, "0123456789");
 352         f = new(char, sizeof("/tmp/.X11-unix/X") + k);
 353         if (!f) {
 354                 log_error("Out of memory");
 355                 return -ENOMEM;
 356         }
 357
 358         c = stpcpy(f, "/tmp/.X11-unix/X");
 359         memcpy(c, s->display+1, k);
 360         c[k] = 0;
 361
 362         if (access(f, F_OK) < 0) {
 363                 log_warning("Session %s has display %s with nonexisting socket %s.", s->id, s->display, f);
 364                 free(f);
 365                 return -ENOENT;
 366         }
 367
 368         t = strappend(s->user->runtime_path, "/display");
 369         if (!t) {
 370                 log_error("Out of memory");
 371                 free(f);
 372                 return -ENOMEM;
 373         }
 374
 375         if (link(f, t) < 0) {
 376                 if (errno == EEXIST) {
 377                         unlink(t);
 378
 379                         if (link(f, t) >= 0)
 380                                 goto done;
 381                 }
 382
 383                 if (symlink(f, t) < 0) {
 384
 385                         if (errno == EEXIST) {
 386                                 unlink(t);
 387
 388                                 if (symlink(f, t) >= 0)
 389                                         goto done;
 390                         }
 391
 392                         log_error("Failed to link %s to %s: %m", f, t);
 393                         free(f);
 394                         free(t);
 395                         return -errno;
 396                 }
 397         }
 398
 399 done:
 400         log_info("Linked %s to %s.", f, t);
 401         free(f);
 402         free(t);
 403
 404         s->user->display = s;
 405
 406         return 0;
 407 }
 408
 409 static int session_create_one_group(Session *s, const char *controller, const char *path) {
 410         int r;
 411
 412         assert(s);
 413         assert(controller);
 414         assert(path);
 415
 416         if (s->leader > 0)
 417                 r = cg_create_and_attach(controller, path, s->leader);
 418         else
 419                 r = cg_create(controller, path);
 420
 421         if (r < 0)
 422                 return r;
 423
 424         r = cg_set_task_access(controller, path, 0644, s->user->uid, s->user->gid);
 425         if (r >= 0)
 426                 r = cg_set_group_access(controller, path, 0755, s->user->uid, s->user->gid);
 427
 428         return r;
 429 }
 430
 431 static int session_create_cgroup(Session *s) {
 432         char **k;
 433         char *p;
 434         int r;
 435
 436         assert(s);
 437         assert(s->user);
 438         assert(s->user->cgroup_path);
 439
 440         if (!s->cgroup_path) {
 441                 if (asprintf(&p, "%s/%s", s->user->cgroup_path, s->id) < 0) {
 442                         log_error("Out of memory");
 443                         return -ENOMEM;
 444                 }
 445         } else
 446                 p = s->cgroup_path;
 447
 448         r = session_create_one_group(s, SYSTEMD_CGROUP_CONTROLLER, p);
 449         if (r < 0) {
 450                 free(p);
 451                 s->cgroup_path = NULL;
 452                 log_error("Failed to create "SYSTEMD_CGROUP_CONTROLLER":%s: %s", p, strerror(-r));
 453                 return r;
 454         }
 455
 456         s->cgroup_path = p;
 457
 458         STRV_FOREACH(k, s->controllers) {
 459
 460                 if (strv_contains(s->reset_controllers, *k))
 461                         continue;
 462
 463                 r = session_create_one_group(s, *k, p);
 464                 if (r < 0)
 465                         log_warning("Failed to create %s:%s: %s", *k, p, strerror(-r));
 466         }
 467
 468         STRV_FOREACH(k, s->manager->controllers) {
 469
 470                 if (strv_contains(s->reset_controllers, *k) ||
 471                     strv_contains(s->controllers, *k))
 472                         continue;
 473
 474                 r = session_create_one_group(s, *k, p);
 475                 if (r < 0)
 476                         log_warning("Failed to create %s:%s: %s", *k, p, strerror(-r));
 477         }
 478
 479         if (s->leader > 0) {
 480
 481                 STRV_FOREACH(k, s->reset_controllers) {
 482                         r = cg_attach(*k, "/", s->leader);
 483                         if (r < 0)
 484                                 log_warning("Failed to reset controller %s: %s", *k, strerror(-r));
 485
 486                 }
 487         }
 488
 489         hashmap_put(s->manager->cgroups, s->cgroup_path, s);
 490
 491         return 0;
 492 }
 493
 494 int session_start(Session *s) {
 495         int r;
 496
 497         assert(s);
 498         assert(s->user);
 499
 500         if (s->started)
 501                 return 0;
 502
 503         r = user_start(s->user);
 504         if (r < 0)
 505                 return r;
 506
 507         log_info("New session %s of user %s.", s->id, s->user->name);
 508
 509         /* Create cgroup */
 510         r = session_create_cgroup(s);
 511         if (r < 0)
 512                 return r;
 513
 514         /* Create X11 symlink */
 515         session_link_x11_socket(s);
 516
 517         /* Save session data */
 518         session_save(s);
 519
 520         dual_timestamp_get(&s->timestamp);
 521
 522         s->started = true;
 523
 524         session_send_signal(s, true);
 525
 526         if (s->seat) {
 527                 if (s->seat->active == s)
 528                         seat_send_changed(s->seat, "Sessions\0ActiveSession\0");
 529                 else
 530                         seat_send_changed(s->seat, "Sessions\0");
 531         }
 532
 533         user_send_changed(s->user, "Sessions\0");
 534
 535         return 0;
 536 }
 537
 538 static bool session_shall_kill(Session *s) {
 539         assert(s);
 540
 541         if (!s->kill_processes)
 542                 return false;
 543
 544         if (strv_contains(s->manager->kill_exclude_users, s->user->name))
 545                 return false;
 546
 547         if (strv_isempty(s->manager->kill_only_users))
 548                 return true;
 549
 550         return strv_contains(s->manager->kill_only_users, s->user->name);
 551 }
 552
 553 static int session_kill_cgroup(Session *s) {
 554         int r;
 555         char **k;
 556
 557         assert(s);
 558
 559         if (!s->cgroup_path)
 560                 return 0;
 561
 562         cg_trim(SYSTEMD_CGROUP_CONTROLLER, s->cgroup_path, false);
 563
 564         if (session_shall_kill(s)) {
 565
 566                 r = cg_kill_recursive_and_wait(SYSTEMD_CGROUP_CONTROLLER, s->cgroup_path, true);
 567                 if (r < 0)
 568                         log_error("Failed to kill session cgroup: %s", strerror(-r));
 569
 570         } else {
 571                 r = cg_is_empty_recursive(SYSTEMD_CGROUP_CONTROLLER, s->cgroup_path, true);
 572                 if (r < 0)
 573                         log_error("Failed to check session cgroup: %s", strerror(-r));
 574                 else if (r > 0) {
 575                         r = cg_delete(SYSTEMD_CGROUP_CONTROLLER, s->cgroup_path);
 576                         if (r < 0)
 577                                 log_error("Failed to delete session cgroup: %s", strerror(-r));
 578                 } else
 579                         r = -EBUSY;
 580         }
 581
 582         STRV_FOREACH(k, s->user->manager->controllers)
 583                 cg_trim(*k, s->cgroup_path, true);
 584
 585         hashmap_remove(s->manager->cgroups, s->cgroup_path);
 586
 587         free(s->cgroup_path);
 588         s->cgroup_path = NULL;
 589
 590         return r;
 591 }
 592
 593 static int session_unlink_x11_socket(Session *s) {
 594         char *t;
 595         int r;
 596
 597         assert(s);
 598         assert(s->user);
 599
 600         if (s->user->display != s)
 601                 return 0;
 602
 603         s->user->display = NULL;
 604
 605         t = strappend(s->user->runtime_path, "/display");
 606         if (!t) {
 607                 log_error("Out of memory");
 608                 return -ENOMEM;
 609         }
 610
 611         r = unlink(t);
 612         free(t);
 613
 614         return r < 0 ? -errno : 0;
 615 }
 616
 617 int session_stop(Session *s) {
 618         int r = 0, k;
 619
 620         assert(s);
 621
 622         if (s->started)
 623                 log_info("Removed session %s.", s->id);
 624
 625         /* Kill cgroup */
 626         k = session_kill_cgroup(s);
 627         if (k < 0)
 628                 r = k;
 629
 630         /* Remove X11 symlink */
 631         session_unlink_x11_socket(s);
 632
 633         unlink(s->state_file);
 634         session_add_to_gc_queue(s);
 635         user_add_to_gc_queue(s->user);
 636
 637         if (s->started)
 638                 session_send_signal(s, false);
 639
 640         if (s->seat) {
 641                 if (s->seat->active == s)
 642                         seat_set_active(s->seat, NULL);
 643
 644                 seat_send_changed(s->seat, "Sessions\0");
 645         }
 646
 647         user_send_changed(s->user, "Sessions\0");
 648
 649         s->started = false;
 650
 651         return r;
 652 }
 653
 654 bool session_is_active(Session *s) {
 655         assert(s);
 656
 657         if (!s->seat)
 658                 return true;
 659
 660         return s->seat->active == s;
 661 }
 662
 663 int session_get_idle_hint(Session *s, dual_timestamp *t) {
 664         char *p;
 665         struct stat st;
 666         usec_t u, n;
 667         bool b;
 668         int k;
 669
 670         assert(s);
 671
 672         if (s->idle_hint) {
 673                 if (t)
 674                         *t = s->idle_hint_timestamp;
 675
 676                 return s->idle_hint;
 677         }
 678
 679         if (isempty(s->tty))
 680                 goto dont_know;
 681
 682         if (s->tty[0] != '/') {
 683                 p = strappend("/dev/", s->tty);
 684                 if (!p)
 685                         return -ENOMEM;
 686         } else
 687                 p = NULL;
 688
 689         if (!startswith(p ? p : s->tty, "/dev/")) {
 690                 free(p);
 691                 goto dont_know;
 692         }
 693
 694         k = lstat(p ? p : s->tty, &st);
 695         free(p);
 696
 697         if (k < 0)
 698                 goto dont_know;
 699
 700         u = timespec_load(&st.st_atim);
 701         n = now(CLOCK_REALTIME);
 702         b = u + IDLE_THRESHOLD_USEC < n;
 703
 704         if (t)
 705                 dual_timestamp_from_realtime(t, u + b ? IDLE_THRESHOLD_USEC : 0);
 706
 707         return b;
 708
 709 dont_know:
 710         if (t)
 711                 *t = s->idle_hint_timestamp;
 712
 713         return 0;
 714 }
 715
 716 void session_set_idle_hint(Session *s, bool b) {
 717         assert(s);
 718
 719         if (s->idle_hint == b)
 720                 return;
 721
 722         s->idle_hint = b;
 723         dual_timestamp_get(&s->idle_hint_timestamp);
 724
 725         session_send_changed(s,
 726                              "IdleHint\0"
 727                              "IdleSinceHint\0"
 728                              "IdleSinceHintMonotonic\0");
 729
 730         if (s->seat)
 731                 seat_send_changed(s->seat,
 732                                   "IdleHint\0"
 733                                   "IdleSinceHint\0"
 734                                   "IdleSinceHintMonotonic\0");
 735
 736         user_send_changed(s->user,
 737                           "IdleHint\0"
 738                           "IdleSinceHint\0"
 739                           "IdleSinceHintMonotonic\0");
 740
 741         manager_send_changed(s->manager,
 742                              "IdleHint\0"
 743                              "IdleSinceHint\0"
 744                              "IdleSinceHintMonotonic\0");
 745 }
 746
 747 int session_set_pipe_fd(Session *s, int fd) {
 748         struct epoll_event ev;
 749         int r;
 750
 751         assert(s);
 752         assert(fd >= 0);
 753         assert(s->pipe_fd < 0);
 754
 755         r = hashmap_put(s->manager->pipe_fds, INT_TO_PTR(fd + 1), s);
 756         if (r < 0)
 757                 return r;
 758
 759         zero(ev);
 760         ev.events = 0;
 761         ev.data.u32 = FD_PIPE_BASE + fd;
 762
 763         if (epoll_ctl(s->manager->epoll_fd, EPOLL_CTL_ADD, fd, &ev) < 0) {
 764                 assert_se(hashmap_remove(s->manager->pipe_fds, INT_TO_PTR(fd + 1)) == s);
 765                 return -errno;
 766         }
 767
 768         s->pipe_fd = fd;
 769         return 0;
 770 }
 771
 772 void session_unset_pipe_fd(Session *s) {
 773         assert(s);
 774
 775         if (s->pipe_fd < 0)
 776                 return;
 777
 778         assert_se(hashmap_remove(s->manager->pipe_fds, INT_TO_PTR(s->pipe_fd + 1)) == s);
 779
 780         assert_se(epoll_ctl(s->manager->epoll_fd, EPOLL_CTL_DEL, s->pipe_fd, NULL) == 0);
 781
 782         close_nointr_nofail(s->pipe_fd);
 783         s->pipe_fd = -1;
 784 }
 785
 786 int session_check_gc(Session *s) {
 787         int r;
 788
 789         assert(s);
 790
 791         if (s->pipe_fd >= 0) {
 792
 793                 r = pipe_eof(s->pipe_fd);
 794                 if (r < 0)
 795                         return r;
 796
 797                 if (r == 0)
 798                         return 1;
 799         }
 800
 801         if (s->cgroup_path) {
 802
 803                 r = cg_is_empty_recursive(SYSTEMD_CGROUP_CONTROLLER, s->cgroup_path, false);
 804                 if (r < 0)
 805                         return r;
 806
 807                 if (r <= 0)
 808                         return 1;
 809         }
 810
 811         return 0;
 812 }
 813
 814 void session_add_to_gc_queue(Session *s) {
 815         assert(s);
 816
 817         if (s->in_gc_queue)
 818                 return;
 819
 820         LIST_PREPEND(Session, gc_queue, s->manager->session_gc_queue, s);
 821         s->in_gc_queue = true;
 822 }
 823
 824 static const char* const session_type_table[_SESSION_TYPE_MAX] = {
 825         [SESSION_TTY] = "tty",
 826         [SESSION_X11] = "x11",
 827         [SESSION_UNSPECIFIED] = "unspecified"
 828 };
 829
 830 DEFINE_STRING_TABLE_LOOKUP(session_type, SessionType);