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         if (!s->started)
 115                 return 0;
 116
 117         r = safe_mkdir("/run/systemd/sessions", 0755, 0, 0);
 118         if (r < 0)
 119                 goto finish;
 120
 121         r = fopen_temporary(s->state_file, &f, &temp_path);
 122         if (r < 0)
 123                 goto finish;
 124
 125         assert(s->user);
 126
 127         fchmod(fileno(f), 0644);
 128
 129         fprintf(f,
 130                 "# This is private data. Do not parse.\n"
 131                 "UID=%lu\n"
 132                 "USER=%s\n"
 133                 "ACTIVE=%i\n"
 134                 "REMOTE=%i\n"
 135                 "KILL_PROCESSES=%i\n",
 136                 (unsigned long) s->user->uid,
 137                 s->user->name,
 138                 session_is_active(s),
 139                 s->remote,
 140                 s->kill_processes);
 141
 142         if (s->type >= 0)
 143                 fprintf(f,
 144                         "TYPE=%s\n",
 145                         session_type_to_string(s->type));
 146
 147         if (s->cgroup_path)
 148                 fprintf(f,
 149                         "CGROUP=%s\n",
 150                         s->cgroup_path);
 151
 152         if (s->seat)
 153                 fprintf(f,
 154                         "SEAT=%s\n",
 155                         s->seat->id);
 156
 157         if (s->tty)
 158                 fprintf(f,
 159                         "TTY=%s\n",
 160                         s->tty);
 161
 162         if (s->display)
 163                 fprintf(f,
 164                         "DISPLAY=%s\n",
 165                         s->display);
 166
 167         if (s->remote_host)
 168                 fprintf(f,
 169                         "REMOTE_HOST=%s\n",
 170                         s->remote_host);
 171
 172         if (s->remote_user)
 173                 fprintf(f,
 174                         "REMOTE_USER=%s\n",
 175                         s->remote_user);
 176
 177         if (s->service)
 178                 fprintf(f,
 179                         "SERVICE=%s\n",
 180                         s->service);
 181
 182         if (s->seat && seat_is_vtconsole(s->seat))
 183                 fprintf(f,
 184                         "VTNR=%i\n",
 185                         s->vtnr);
 186
 187         if (s->leader > 0)
 188                 fprintf(f,
 189                         "LEADER=%lu\n",
 190                         (unsigned long) s->leader);
 191
 192         if (s->audit_id > 0)
 193                 fprintf(f,
 194                         "AUDIT=%llu\n",
 195                         (unsigned long long) s->audit_id);
 196
 197         fflush(f);
 198
 199         if (ferror(f) || rename(temp_path, s->state_file) < 0) {
 200                 r = -errno;
 201                 unlink(s->state_file);
 202                 unlink(temp_path);
 203         }
 204
 205         fclose(f);
 206         free(temp_path);
 207
 208 finish:
 209         if (r < 0)
 210                 log_error("Failed to save session data for %s: %s", s->id, strerror(-r));
 211
 212         return r;
 213 }
 214
 215 int session_load(Session *s) {
 216         char *remote = NULL,
 217                 *kill_processes = NULL,
 218                 *seat = NULL,
 219                 *vtnr = NULL,
 220                 *leader = NULL,
 221                 *audit_id = NULL,
 222                 *type = NULL;
 223
 224         int k, r;
 225
 226         assert(s);
 227
 228         r = parse_env_file(s->state_file, NEWLINE,
 229                            "REMOTE",         &remote,
 230                            "KILL_PROCESSES", &kill_processes,
 231                            "CGROUP",         &s->cgroup_path,
 232                            "SEAT",           &seat,
 233                            "TTY",            &s->tty,
 234                            "DISPLAY",        &s->display,
 235                            "REMOTE_HOST",    &s->remote_host,
 236                            "REMOTE_USER",    &s->remote_user,
 237                            "SERVICE",        &s->service,
 238                            "VTNR",           &vtnr,
 239                            "LEADER",         &leader,
 240                            "TYPE",           &type,
 241                            NULL);
 242
 243         if (r < 0)
 244                 goto finish;
 245
 246         if (remote) {
 247                 k = parse_boolean(remote);
 248                 if (k >= 0)
 249                         s->remote = k;
 250         }
 251
 252         if (kill_processes) {
 253                 k = parse_boolean(kill_processes);
 254                 if (k >= 0)
 255                         s->kill_processes = k;
 256         }
 257
 258         if (seat && !s->seat) {
 259                 Seat *o;
 260
 261                 o = hashmap_get(s->manager->seats, seat);
 262                 if (o)
 263                         seat_attach_session(o, s);
 264         }
 265
 266         if (vtnr && s->seat && seat_is_vtconsole(s->seat)) {
 267                 int v;
 268
 269                 k = safe_atoi(vtnr, &v);
 270                 if (k >= 0 && v >= 1)
 271                         s->vtnr = v;
 272         }
 273
 274         if (leader) {
 275                 pid_t pid;
 276
 277                 k = parse_pid(leader, &pid);
 278                 if (k >= 0 && pid >= 1) {
 279                         s->leader = pid;
 280
 281                         audit_session_from_pid(pid, &s->audit_id);
 282                 }
 283         }
 284
 285         if (type) {
 286                 SessionType t;
 287
 288                 t = session_type_from_string(type);
 289                 if (t >= 0)
 290                         s->type = t;
 291         }
 292
 293 finish:
 294         free(remote);
 295         free(kill_processes);
 296         free(seat);
 297         free(vtnr);
 298         free(leader);
 299         free(audit_id);
 300
 301         return r;
 302 }
 303
 304 int session_activate(Session *s) {
 305         int r;
 306         Session *old_active;
 307
 308         assert(s);
 309
 310         if (s->vtnr < 0)
 311                 return -ENOTSUP;
 312
 313         if (!s->seat)
 314                 return -ENOTSUP;
 315
 316         if (s->seat->active == s)
 317                 return 0;
 318
 319         assert(seat_is_vtconsole(s->seat));
 320
 321         r = chvt(s->vtnr);
 322         if (r < 0)
 323                 return r;
 324
 325         old_active = s->seat->active;
 326         s->seat->active = s;
 327
 328         return seat_apply_acls(s->seat, old_active);
 329 }
 330
 331
 332 static int session_link_x11_socket(Session *s) {
 333         char *t, *f, *c;
 334         size_t k;
 335
 336         assert(s);
 337         assert(s->user);
 338         assert(s->user->runtime_path);
 339
 340         if (s->user->display)
 341                 return 0;
 342
 343         if (!s->display || !display_is_local(s->display))
 344                 return 0;
 345
 346         k = strspn(s->display+1, "0123456789");
 347         f = new(char, sizeof("/tmp/.X11-unix/X") + k);
 348         if (!f) {
 349                 log_error("Out of memory");
 350                 return -ENOMEM;
 351         }
 352
 353         c = stpcpy(f, "/tmp/.X11-unix/X");
 354         memcpy(c, s->display+1, k);
 355         c[k] = 0;
 356
 357         if (access(f, F_OK) < 0) {
 358                 log_warning("Session %s has display %s with nonexisting socket %s.", s->id, s->display, f);
 359                 free(f);
 360                 return -ENOENT;
 361         }
 362
 363         t = strappend(s->user->runtime_path, "/display");
 364         if (!t) {
 365                 log_error("Out of memory");
 366                 free(f);
 367                 return -ENOMEM;
 368         }
 369
 370         if (link(f, t) < 0) {
 371                 if (errno == EEXIST) {
 372                         unlink(t);
 373
 374                         if (link(f, t) >= 0)
 375                                 goto done;
 376                 }
 377
 378                 if (symlink(f, t) < 0) {
 379
 380                         if (errno == EEXIST) {
 381                                 unlink(t);
 382
 383                                 if (symlink(f, t) >= 0)
 384                                         goto done;
 385                         }
 386
 387                         log_error("Failed to link %s to %s: %m", f, t);
 388                         free(f);
 389                         free(t);
 390                         return -errno;
 391                 }
 392         }
 393
 394 done:
 395         log_info("Linked %s to %s.", f, t);
 396         free(f);
 397         free(t);
 398
 399         s->user->display = s;
 400
 401         return 0;
 402 }
 403
 404 static int session_create_one_group(Session *s, const char *controller, const char *path) {
 405         int r;
 406
 407         assert(s);
 408         assert(controller);
 409         assert(path);
 410
 411         if (s->leader > 0) {
 412                 r = cg_create_and_attach(controller, path, s->leader);
 413                 if (r < 0)
 414                         r = cg_create(controller, path);
 415         } else
 416                 r = cg_create(controller, path);
 417
 418         if (r < 0)
 419                 return r;
 420
 421         r = cg_set_task_access(controller, path, 0644, s->user->uid, s->user->gid);
 422         if (r >= 0)
 423                 r = cg_set_group_access(controller, path, 0755, s->user->uid, s->user->gid);
 424
 425         return r;
 426 }
 427
 428 static int session_create_cgroup(Session *s) {
 429         char **k;
 430         char *p;
 431         int r;
 432
 433         assert(s);
 434         assert(s->user);
 435         assert(s->user->cgroup_path);
 436
 437         if (!s->cgroup_path) {
 438                 if (asprintf(&p, "%s/%s", s->user->cgroup_path, s->id) < 0) {
 439                         log_error("Out of memory");
 440                         return -ENOMEM;
 441                 }
 442         } else
 443                 p = s->cgroup_path;
 444
 445         r = session_create_one_group(s, SYSTEMD_CGROUP_CONTROLLER, p);
 446         if (r < 0) {
 447                 log_error("Failed to create "SYSTEMD_CGROUP_CONTROLLER":%s: %s", p, strerror(-r));
 448                 free(p);
 449                 s->cgroup_path = NULL;
 450                 return r;
 451         }
 452
 453         s->cgroup_path = p;
 454
 455         STRV_FOREACH(k, s->controllers) {
 456
 457                 if (strv_contains(s->reset_controllers, *k))
 458                         continue;
 459
 460                 r = session_create_one_group(s, *k, p);
 461                 if (r < 0)
 462                         log_warning("Failed to create %s:%s: %s", *k, p, strerror(-r));
 463         }
 464
 465         STRV_FOREACH(k, s->manager->controllers) {
 466
 467                 if (strv_contains(s->reset_controllers, *k) ||
 468                     strv_contains(s->controllers, *k))
 469                         continue;
 470
 471                 r = session_create_one_group(s, *k, p);
 472                 if (r < 0)
 473                         log_warning("Failed to create %s:%s: %s", *k, p, strerror(-r));
 474         }
 475
 476         if (s->leader > 0) {
 477
 478                 STRV_FOREACH(k, s->reset_controllers) {
 479                         r = cg_attach(*k, "/", s->leader);
 480                         if (r < 0)
 481                                 log_warning("Failed to reset controller %s: %s", *k, strerror(-r));
 482
 483                 }
 484         }
 485
 486         hashmap_put(s->manager->cgroups, s->cgroup_path, s);
 487
 488         return 0;
 489 }
 490
 491 int session_start(Session *s) {
 492         int r;
 493
 494         assert(s);
 495         assert(s->user);
 496
 497         if (s->started)
 498                 return 0;
 499
 500         r = user_start(s->user);
 501         if (r < 0)
 502                 return r;
 503
 504         log_info("New session %s of user %s.", s->id, s->user->name);
 505
 506         /* Create cgroup */
 507         r = session_create_cgroup(s);
 508         if (r < 0)
 509                 return r;
 510
 511         /* Create X11 symlink */
 512         session_link_x11_socket(s);
 513
 514         dual_timestamp_get(&s->timestamp);
 515
 516         if (s->seat)
 517                 seat_read_active_vt(s->seat);
 518
 519         s->started = true;
 520
 521         /* Save session data */
 522         session_save(s);
 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);