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/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         r = safe_mkdir("/run/systemd/seats", 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         seat_save(s);
 250
 251         if (session)
 252                 session_save(session);
 253
 254         if (old_active)
 255                 session_save(old_active);
 256
 257         return 0;
 258 }
 259
 260 int seat_active_vt_changed(Seat *s, int vtnr) {
 261         Session *i, *new_active = NULL;
 262         int r;
 263
 264         assert(s);
 265         assert(vtnr >= 1);
 266
 267         if (!seat_is_vtconsole(s))
 268                 return -EINVAL;
 269
 270         log_debug("VT changed to %i", vtnr);
 271
 272         LIST_FOREACH(sessions_by_seat, i, s->sessions)
 273                 if (i->vtnr == vtnr) {
 274                         new_active = i;
 275                         break;
 276                 }
 277
 278         r = seat_set_active(s, new_active);
 279         manager_spawn_autovt(s->manager, vtnr);
 280
 281         return r;
 282 }
 283
 284 int seat_read_active_vt(Seat *s) {
 285         char t[64];
 286         ssize_t k;
 287         int r, vtnr;
 288
 289         assert(s);
 290
 291         if (!seat_is_vtconsole(s))
 292                 return 0;
 293
 294         lseek(s->manager->console_active_fd, SEEK_SET, 0);
 295
 296         k = read(s->manager->console_active_fd, t, sizeof(t)-1);
 297         if (k <= 0) {
 298                 log_error("Failed to read current console: %s", k < 0 ? strerror(-errno) : "EOF");
 299                 return k < 0 ? -errno : -EIO;
 300         }
 301
 302         t[k] = 0;
 303         truncate_nl(t);
 304
 305         if (!startswith(t, "tty")) {
 306                 log_error("Hm, /sys/class/tty/tty0/active is badly formatted.");
 307                 return -EIO;
 308         }
 309
 310         r = safe_atoi(t+3, &vtnr);
 311         if (r < 0) {
 312                 log_error("Failed to parse VT number %s", t+3);
 313                 return r;
 314         }
 315
 316         if (vtnr <= 0) {
 317                 log_error("VT number invalid: %s", t+3);
 318                 return -EIO;
 319         }
 320
 321         return seat_active_vt_changed(s, vtnr);
 322 }
 323
 324 int seat_start(Seat *s) {
 325         assert(s);
 326
 327         if (s->started)
 328                 return 0;
 329
 330         log_info("New seat %s.", s->id);
 331
 332         /* Initialize VT magic stuff */
 333         seat_preallocate_vts(s);
 334
 335         /* Read current VT */
 336         seat_read_active_vt(s);
 337
 338         /* Save seat data */
 339         seat_save(s);
 340
 341         s->started = true;
 342
 343         seat_send_signal(s, true);
 344
 345         return 0;
 346 }
 347
 348 int seat_stop(Seat *s) {
 349         int r = 0;
 350
 351         assert(s);
 352
 353         if (s->started)
 354                 log_info("Removed seat %s.", s->id);
 355
 356         seat_stop_sessions(s);
 357
 358         unlink(s->state_file);
 359         seat_add_to_gc_queue(s);
 360
 361         if (s->started)
 362                 seat_send_signal(s, false);
 363
 364         s->started = false;
 365
 366         return r;
 367 }
 368
 369 int seat_stop_sessions(Seat *s) {
 370         Session *session;
 371         int r = 0, k;
 372
 373         assert(s);
 374
 375         LIST_FOREACH(sessions_by_seat, session, s->sessions) {
 376                 k = session_stop(session);
 377                 if (k < 0)
 378                         r = k;
 379         }
 380
 381         return r;
 382 }
 383
 384 int seat_attach_session(Seat *s, Session *session) {
 385         assert(s);
 386         assert(session);
 387         assert(!session->seat);
 388
 389         if (!seat_is_vtconsole(s) && s->sessions)
 390                 return -EEXIST;
 391
 392         session->seat = s;
 393         LIST_PREPEND(Session, sessions_by_seat, s->sessions, session);
 394
 395         seat_send_changed(s, "Sessions\0");
 396
 397         if (!seat_is_vtconsole(s)) {
 398                 assert(!s->active);
 399                 seat_set_active(s, session);
 400         }
 401
 402         return 0;
 403 }
 404
 405 bool seat_is_vtconsole(Seat *s) {
 406         assert(s);
 407
 408         return s->manager->vtconsole == s;
 409 }
 410
 411 int seat_get_idle_hint(Seat *s, dual_timestamp *t) {
 412         Session *session;
 413         bool idle_hint = true;
 414         dual_timestamp ts = { 0, 0 };
 415
 416         assert(s);
 417
 418         LIST_FOREACH(sessions_by_seat, session, s->sessions) {
 419                 dual_timestamp k;
 420                 int ih;
 421
 422                 ih = session_get_idle_hint(session, &k);
 423                 if (ih < 0)
 424                         return ih;
 425
 426                 if (!ih) {
 427                         if (!idle_hint) {
 428                                 if (k.monotonic < ts.monotonic)
 429                                         ts = k;
 430                         } else {
 431                                 idle_hint = false;
 432                                 ts = k;
 433                         }
 434                 } else if (idle_hint) {
 435
 436                         if (k.monotonic > ts.monotonic)
 437                                 ts = k;
 438                 }
 439         }
 440
 441         if (t)
 442                 *t = ts;
 443
 444         return idle_hint;
 445 }
 446
 447 int seat_check_gc(Seat *s) {
 448         assert(s);
 449
 450         if (seat_is_vtconsole(s))
 451                 return 1;
 452
 453         return !!s->devices;
 454 }
 455
 456 void seat_add_to_gc_queue(Seat *s) {
 457         assert(s);
 458
 459         if (s->in_gc_queue)
 460                 return;
 461
 462         LIST_PREPEND(Seat, gc_queue, s->manager->seat_gc_queue, s);
 463         s->in_gc_queue = true;
 464 }
 465
 466 static bool seat_name_valid_char(char c) {
 467         return
 468                 (c >= 'a' && c <= 'z') ||
 469                 (c >= 'A' && c <= 'Z') ||
 470                 (c >= '0' && c <= '9') ||
 471                 c == '-' ||
 472                 c == '_';
 473 }
 474
 475 bool seat_name_is_valid(const char *name) {
 476         const char *p;
 477
 478         assert(name);
 479
 480         if (!startswith(name, "seat"))
 481                 return false;
 482
 483         if (!name[4])
 484                 return false;
 485
 486         for (p = name; *p; p++)
 487                 if (!seat_name_valid_char(*p))
 488                         return false;
 489
 490         return true;
 491 }