src/login/logind-seat.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 <assert.h>
  23 #include <errno.h>
  24 #include <unistd.h>
  25 #include <fcntl.h>
  26 #include <sys/ioctl.h>
  27 #include <linux/vt.h>
  28 #include <string.h>
  29
  30 #include "logind-seat.h"
  31 #include "logind-acl.h"
  32 #include "util.h"
  33
  34 Seat *seat_new(Manager *m, const char *id) {
  35         Seat *s;
  36
  37         assert(m);
  38         assert(id);
  39
  40         s = new0(Seat, 1);
  41         if (!s)
  42                 return NULL;
  43
  44         s->state_file = strappend("/run/systemd/seats/", 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         s->manager = m;
  52
  53         if (hashmap_put(m->seats, s->id, s) < 0) {
  54                 free(s->state_file);
  55                 free(s);
  56                 return NULL;
  57         }
  58
  59         return s;
  60 }
  61
  62 void seat_free(Seat *s) {
  63         assert(s);
  64
  65         if (s->in_gc_queue)
  66                 LIST_REMOVE(Seat, gc_queue, s->manager->seat_gc_queue, s);
  67
  68         while (s->sessions)
  69                 session_free(s->sessions);
  70
  71         assert(!s->active);
  72
  73         while (s->devices)
  74                 device_free(s->devices);
  75
  76         hashmap_remove(s->manager->seats, s->id);
  77
  78         free(s->state_file);
  79         free(s);
  80 }
  81
  82 int seat_save(Seat *s) {
  83         int r;
  84         FILE *f;
  85         char *temp_path;
  86
  87         assert(s);
  88
  89         if (!s->started)
  90                 return 0;
  91
  92         r = safe_mkdir("/run/systemd/seats", 0755, 0, 0);
  93         if (r < 0)
  94                 goto finish;
  95
  96         r = fopen_temporary(s->state_file, &f, &temp_path);
  97         if (r < 0)
  98                 goto finish;
  99
 100         fchmod(fileno(f), 0644);
 101
 102         fprintf(f,
 103                 "# This is private data. Do not parse.\n"
 104                 "IS_VTCONSOLE=%i\n",
 105                 seat_is_vtconsole(s));
 106
 107         if (s->active) {
 108                 assert(s->active->user);
 109
 110                 fprintf(f,
 111                         "ACTIVE=%s\n"
 112                         "ACTIVE_UID=%lu\n",
 113                         s->active->id,
 114                         (unsigned long) s->active->user->uid);
 115         }
 116
 117         if (s->sessions) {
 118                 Session *i;
 119
 120                 fputs("SESSIONS=", f);
 121                 LIST_FOREACH(sessions_by_seat, i, s->sessions) {
 122                         fprintf(f,
 123                                 "%s%c",
 124                                 i->id,
 125                                 i->sessions_by_seat_next ? ' ' : '\n');
 126                 }
 127
 128                 fputs("UIDS=", f);
 129                 LIST_FOREACH(sessions_by_seat, i, s->sessions)
 130                         fprintf(f,
 131                                 "%lu%c",
 132                                 (unsigned long) i->user->uid,
 133                                 i->sessions_by_seat_next ? ' ' : '\n');
 134         }
 135
 136         fflush(f);
 137
 138         if (ferror(f) || rename(temp_path, s->state_file) < 0) {
 139                 r = -errno;
 140                 unlink(s->state_file);
 141                 unlink(temp_path);
 142         }
 143
 144         fclose(f);
 145         free(temp_path);
 146
 147 finish:
 148         if (r < 0)
 149                 log_error("Failed to save seat data for %s: %s", s->id, strerror(-r));
 150
 151         return r;
 152 }
 153
 154 int seat_load(Seat *s) {
 155         assert(s);
 156
 157         /* There isn't actually anything to read here ... */
 158
 159         return 0;
 160 }
 161
 162 static int vt_allocate(int vtnr) {
 163         int fd, r;
 164         char *p;
 165
 166         assert(vtnr >= 1);
 167
 168         if (asprintf(&p, "/dev/tty%i", vtnr) < 0)
 169                 return -ENOMEM;
 170
 171         fd = open_terminal(p, O_RDWR|O_NOCTTY|O_CLOEXEC);
 172         free(p);
 173
 174         r = fd < 0 ? -errno : 0;
 175
 176         if (fd >= 0)
 177                 close_nointr_nofail(fd);
 178
 179         return r;
 180 }
 181
 182 int seat_preallocate_vts(Seat *s) {
 183         int r = 0;
 184         unsigned i;
 185
 186         assert(s);
 187         assert(s->manager);
 188
 189         log_debug("Preallocating VTs...");
 190
 191         if (s->manager->n_autovts <= 0)
 192                 return 0;
 193
 194         if (!seat_is_vtconsole(s))
 195                 return 0;
 196
 197         for (i = 1; i <= s->manager->n_autovts; i++) {
 198                 int q;
 199
 200                 q = vt_allocate(i);
 201                 if (q < 0) {
 202                         log_error("Failed to preallocate VT %i: %s", i, strerror(-q));
 203                         r = q;
 204                 }
 205         }
 206
 207         return r;
 208 }
 209
 210 int seat_apply_acls(Seat *s, Session *old_active) {
 211         int r;
 212
 213         assert(s);
 214
 215         r = devnode_acl_all(s->manager->udev,
 216                             s->id,
 217                             false,
 218                             !!old_active, old_active ? old_active->user->uid : 0,
 219                             !!s->active, s->active ? s->active->user->uid : 0);
 220
 221         if (r < 0)
 222                 log_error("Failed to apply ACLs: %s", strerror(-r));
 223
 224         return r;
 225 }
 226
 227 int seat_set_active(Seat *s, Session *session) {
 228         Session *old_active;
 229
 230         assert(s);
 231         assert(!session || session->seat == s);
 232
 233         if (session == s->active)
 234                 return 0;
 235
 236         old_active = s->active;
 237         s->active = session;
 238
 239         seat_apply_acls(s, old_active);
 240
 241         if (session && session->started)
 242                 session_send_changed(session, "Active\0");
 243
 244         if (!session || session->started)
 245                 seat_send_changed(s, "ActiveSession\0");
 246
 247         seat_save(s);
 248
 249         if (session) {
 250                 session_save(session);
 251                 user_save(session->user);
 252         }
 253
 254         if (old_active) {
 255                 session_save(old_active);
 256                 user_save(old_active->user);
 257         }
 258
 259         return 0;
 260 }
 261
 262 int seat_active_vt_changed(Seat *s, int vtnr) {
 263         Session *i, *new_active = NULL;
 264         int r;
 265
 266         assert(s);
 267         assert(vtnr >= 1);
 268
 269         if (!seat_is_vtconsole(s))
 270                 return -EINVAL;
 271
 272         log_debug("VT changed to %i", vtnr);
 273
 274         LIST_FOREACH(sessions_by_seat, i, s->sessions)
 275                 if (i->vtnr == vtnr) {
 276                         new_active = i;
 277                         break;
 278                 }
 279
 280         r = seat_set_active(s, new_active);
 281         manager_spawn_autovt(s->manager, vtnr);
 282
 283         return r;
 284 }
 285
 286 int seat_read_active_vt(Seat *s) {
 287         char t[64];
 288         ssize_t k;
 289         int r, vtnr;
 290
 291         assert(s);
 292
 293         if (!seat_is_vtconsole(s))
 294                 return 0;
 295
 296         lseek(s->manager->console_active_fd, SEEK_SET, 0);
 297
 298         k = read(s->manager->console_active_fd, t, sizeof(t)-1);
 299         if (k <= 0) {
 300                 log_error("Failed to read current console: %s", k < 0 ? strerror(-errno) : "EOF");
 301                 return k < 0 ? -errno : -EIO;
 302         }
 303
 304         t[k] = 0;
 305         truncate_nl(t);
 306
 307         if (!startswith(t, "tty")) {
 308                 log_error("Hm, /sys/class/tty/tty0/active is badly formatted.");
 309                 return -EIO;
 310         }
 311
 312         r = safe_atoi(t+3, &vtnr);
 313         if (r < 0) {
 314                 log_error("Failed to parse VT number %s", t+3);
 315                 return r;
 316         }
 317
 318         if (vtnr <= 0) {
 319                 log_error("VT number invalid: %s", t+3);
 320                 return -EIO;
 321         }
 322
 323         return seat_active_vt_changed(s, vtnr);
 324 }
 325
 326 int seat_start(Seat *s) {
 327         assert(s);
 328
 329         if (s->started)
 330                 return 0;
 331
 332         log_info("New seat %s.", s->id);
 333
 334         /* Initialize VT magic stuff */
 335         seat_preallocate_vts(s);
 336
 337         /* Read current VT */
 338         seat_read_active_vt(s);
 339
 340         s->started = true;
 341
 342         /* Save seat data */
 343         seat_save(s);
 344
 345         seat_send_signal(s, true);
 346
 347         return 0;
 348 }
 349
 350 int seat_stop(Seat *s) {
 351         int r = 0;
 352
 353         assert(s);
 354
 355         if (s->started)
 356                 log_info("Removed seat %s.", s->id);
 357
 358         seat_stop_sessions(s);
 359
 360         unlink(s->state_file);
 361         seat_add_to_gc_queue(s);
 362
 363         if (s->started)
 364                 seat_send_signal(s, false);
 365
 366         s->started = false;
 367
 368         return r;
 369 }
 370
 371 int seat_stop_sessions(Seat *s) {
 372         Session *session;
 373         int r = 0, k;
 374
 375         assert(s);
 376
 377         LIST_FOREACH(sessions_by_seat, session, s->sessions) {
 378                 k = session_stop(session);
 379                 if (k < 0)
 380                         r = k;
 381         }
 382
 383         return r;
 384 }
 385
 386 int seat_attach_session(Seat *s, Session *session) {
 387         assert(s);
 388         assert(session);
 389         assert(!session->seat);
 390
 391         if (!seat_is_vtconsole(s) && s->sessions)
 392                 return -EEXIST;
 393
 394         session->seat = s;
 395         LIST_PREPEND(Session, sessions_by_seat, s->sessions, session);
 396
 397         seat_send_changed(s, "Sessions\0");
 398
 399         if (!seat_is_vtconsole(s)) {
 400                 assert(!s->active);
 401                 seat_set_active(s, session);
 402         }
 403
 404         return 0;
 405 }
 406
 407 bool seat_is_vtconsole(Seat *s) {
 408         assert(s);
 409
 410         return s->manager->vtconsole == s;
 411 }
 412
 413 int seat_get_idle_hint(Seat *s, dual_timestamp *t) {
 414         Session *session;
 415         bool idle_hint = true;
 416         dual_timestamp ts = { 0, 0 };
 417
 418         assert(s);
 419
 420         LIST_FOREACH(sessions_by_seat, session, s->sessions) {
 421                 dual_timestamp k;
 422                 int ih;
 423
 424                 ih = session_get_idle_hint(session, &k);
 425                 if (ih < 0)
 426                         return ih;
 427
 428                 if (!ih) {
 429                         if (!idle_hint) {
 430                                 if (k.monotonic < ts.monotonic)
 431                                         ts = k;
 432                         } else {
 433                                 idle_hint = false;
 434                                 ts = k;
 435                         }
 436                 } else if (idle_hint) {
 437
 438                         if (k.monotonic > ts.monotonic)
 439                                 ts = k;
 440                 }
 441         }
 442
 443         if (t)
 444                 *t = ts;
 445
 446         return idle_hint;
 447 }
 448
 449 int seat_check_gc(Seat *s, bool drop_not_started) {
 450         assert(s);
 451
 452         if (drop_not_started && !s->started)
 453                 return 0;
 454
 455         if (seat_is_vtconsole(s))
 456                 return 1;
 457
 458         return !!s->devices;
 459 }
 460
 461 void seat_add_to_gc_queue(Seat *s) {
 462         assert(s);
 463
 464         if (s->in_gc_queue)
 465                 return;
 466
 467         LIST_PREPEND(Seat, gc_queue, s->manager->seat_gc_queue, s);
 468         s->in_gc_queue = true;
 469 }
 470
 471 static bool seat_name_valid_char(char c) {
 472         return
 473                 (c >= 'a' && c <= 'z') ||
 474                 (c >= 'A' && c <= 'Z') ||
 475                 (c >= '0' && c <= '9') ||
 476                 c == '-' ||
 477                 c == '_';
 478 }
 479
 480 bool seat_name_is_valid(const char *name) {
 481         const char *p;
 482
 483         assert(name);
 484
 485         if (!startswith(name, "seat"))
 486                 return false;
 487
 488         if (!name[4])
 489                 return false;
 490
 491         for (p = name; *p; p++)
 492                 if (!seat_name_valid_char(*p))
 493                         return false;
 494
 495         if (strlen(name) > 255)
 496                 return false;
 497
 498         return true;
 499 }