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