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         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("OTHER=", f);
 121                 LIST_FOREACH(sessions_by_seat, i, s->sessions) {
 122                         if (i == s->active)
 123                                 continue;
 124
 125                         fprintf(f,
 126                                 "%s%c",
 127                                 i->id,
 128                                 i->sessions_by_seat_next ? ' ' : '\n');
 129                 }
 130
 131                 fputs("OTHER_UIDS=", f);
 132                 LIST_FOREACH(sessions_by_seat, i, s->sessions) {
 133                         if (i == s->active)
 134                                 continue;
 135
 136                         fprintf(f,
 137                                 "%lu%c",
 138                                 (unsigned long) i->user->uid,
 139                                 i->sessions_by_seat_next ? ' ' : '\n');
 140                 }
 141         }
 142
 143         fflush(f);
 144
 145         if (ferror(f) || rename(temp_path, s->state_file) < 0) {
 146                 r = -errno;
 147                 unlink(s->state_file);
 148                 unlink(temp_path);
 149         }
 150
 151         fclose(f);
 152         free(temp_path);
 153
 154 finish:
 155         if (r < 0)
 156                 log_error("Failed to save seat data for %s: %s", s->id, strerror(-r));
 157
 158         return r;
 159 }
 160
 161 int seat_load(Seat *s) {
 162         assert(s);
 163
 164         /* There isn't actually anything to read here ... */
 165
 166         return 0;
 167 }
 168
 169 static int vt_allocate(int vtnr) {
 170         int fd, r;
 171         char *p;
 172
 173         assert(vtnr >= 1);
 174
 175         if (asprintf(&p, "/dev/tty%i", vtnr) < 0)
 176                 return -ENOMEM;
 177
 178         fd = open_terminal(p, O_RDWR|O_NOCTTY|O_CLOEXEC);
 179         free(p);
 180
 181         r = fd < 0 ? -errno : 0;
 182
 183         if (fd >= 0)
 184                 close_nointr_nofail(fd);
 185
 186         return r;
 187 }
 188
 189 int seat_preallocate_vts(Seat *s) {
 190         int r = 0;
 191         unsigned i;
 192
 193         assert(s);
 194         assert(s->manager);
 195
 196         log_debug("Preallocating VTs...");
 197
 198         if (s->manager->n_autovts <= 0)
 199                 return 0;
 200
 201         if (!seat_is_vtconsole(s))
 202                 return 0;
 203
 204         for (i = 1; i <= s->manager->n_autovts; i++) {
 205                 int q;
 206
 207                 q = vt_allocate(i);
 208                 if (q < 0) {
 209                         log_error("Failed to preallocate VT %i: %s", i, strerror(-q));
 210                         r = q;
 211                 }
 212         }
 213
 214         return r;
 215 }
 216
 217 int seat_apply_acls(Seat *s, Session *old_active) {
 218         int r;
 219
 220         assert(s);
 221
 222         r = devnode_acl_all(s->manager->udev,
 223                             s->id,
 224                             false,
 225                             !!old_active, old_active ? old_active->user->uid : 0,
 226                             !!s->active, s->active ? s->active->user->uid : 0);
 227
 228         if (r < 0)
 229                 log_error("Failed to apply ACLs: %s", strerror(-r));
 230
 231         return r;
 232 }
 233
 234 int seat_set_active(Seat *s, Session *session) {
 235         Session *old_active;
 236
 237         assert(s);
 238         assert(!session || session->seat == s);
 239
 240         if (session == s->active)
 241                 return 0;
 242
 243         old_active = s->active;
 244         s->active = session;
 245
 246         seat_apply_acls(s, old_active);
 247
 248         if (session && session->started)
 249                 session_send_changed(session, "Active\0");
 250
 251         if (!session || session->started)
 252                 seat_send_changed(s, "ActiveSession\0");
 253
 254         seat_save(s);
 255
 256         if (session)
 257                 session_save(session);
 258
 259         if (old_active)
 260                 session_save(old_active);
 261
 262         return 0;
 263 }
 264
 265 int seat_active_vt_changed(Seat *s, int vtnr) {
 266         Session *i, *new_active = NULL;
 267         int r;
 268
 269         assert(s);
 270         assert(vtnr >= 1);
 271
 272         if (!seat_is_vtconsole(s))
 273                 return -EINVAL;
 274
 275         log_debug("VT changed to %i", vtnr);
 276
 277         LIST_FOREACH(sessions_by_seat, i, s->sessions)
 278                 if (i->vtnr == vtnr) {
 279                         new_active = i;
 280                         break;
 281                 }
 282
 283         r = seat_set_active(s, new_active);
 284         manager_spawn_autovt(s->manager, vtnr);
 285
 286         return r;
 287 }
 288
 289 int seat_read_active_vt(Seat *s) {
 290         char t[64];
 291         ssize_t k;
 292         int r, vtnr;
 293
 294         assert(s);
 295
 296         if (!seat_is_vtconsole(s))
 297                 return 0;
 298
 299         lseek(s->manager->console_active_fd, SEEK_SET, 0);
 300
 301         k = read(s->manager->console_active_fd, t, sizeof(t)-1);
 302         if (k <= 0) {
 303                 log_error("Failed to read current console: %s", k < 0 ? strerror(-errno) : "EOF");
 304                 return k < 0 ? -errno : -EIO;
 305         }
 306
 307         t[k] = 0;
 308         truncate_nl(t);
 309
 310         if (!startswith(t, "tty")) {
 311                 log_error("Hm, /sys/class/tty/tty0/active is badly formatted.");
 312                 return -EIO;
 313         }
 314
 315         r = safe_atoi(t+3, &vtnr);
 316         if (r < 0) {
 317                 log_error("Failed to parse VT number %s", t+3);
 318                 return r;
 319         }
 320
 321         if (vtnr <= 0) {
 322                 log_error("VT number invalid: %s", t+3);
 323                 return -EIO;
 324         }
 325
 326         return seat_active_vt_changed(s, vtnr);
 327 }
 328
 329 int seat_start(Seat *s) {
 330         assert(s);
 331
 332         if (s->started)
 333                 return 0;
 334
 335         log_info("New seat %s.", s->id);
 336
 337         /* Initialize VT magic stuff */
 338         seat_preallocate_vts(s);
 339
 340         /* Read current VT */
 341         seat_read_active_vt(s);
 342
 343         /* Save seat data */
 344         seat_save(s);
 345
 346         s->started = true;
 347
 348         seat_send_signal(s, true);
 349
 350         return 0;
 351 }
 352
 353 int seat_stop(Seat *s) {
 354         int r = 0;
 355
 356         assert(s);
 357
 358         if (s->started)
 359                 log_info("Removed seat %s.", s->id);
 360
 361         seat_stop_sessions(s);
 362
 363         unlink(s->state_file);
 364         seat_add_to_gc_queue(s);
 365
 366         if (s->started)
 367                 seat_send_signal(s, false);
 368
 369         s->started = false;
 370
 371         return r;
 372 }
 373
 374 int seat_stop_sessions(Seat *s) {
 375         Session *session;
 376         int r = 0, k;
 377
 378         assert(s);
 379
 380         LIST_FOREACH(sessions_by_seat, session, s->sessions) {
 381                 k = session_stop(session);
 382                 if (k < 0)
 383                         r = k;
 384         }
 385
 386         return r;
 387 }
 388
 389 int seat_attach_session(Seat *s, Session *session) {
 390         assert(s);
 391         assert(session);
 392         assert(!session->seat);
 393
 394         if (!seat_is_vtconsole(s) && s->sessions)
 395                 return -EEXIST;
 396
 397         session->seat = s;
 398         LIST_PREPEND(Session, sessions_by_seat, s->sessions, session);
 399
 400         seat_send_changed(s, "Sessions\0");
 401
 402         if (!seat_is_vtconsole(s)) {
 403                 assert(!s->active);
 404                 seat_set_active(s, session);
 405         }
 406
 407         return 0;
 408 }
 409
 410 bool seat_is_vtconsole(Seat *s) {
 411         assert(s);
 412
 413         return s->manager->vtconsole == s;
 414 }
 415
 416 int seat_get_idle_hint(Seat *s, dual_timestamp *t) {
 417         Session *session;
 418         bool idle_hint = true;
 419         dual_timestamp ts = { 0, 0 };
 420
 421         assert(s);
 422
 423         LIST_FOREACH(sessions_by_seat, session, s->sessions) {
 424                 dual_timestamp k;
 425                 int ih;
 426
 427                 ih = session_get_idle_hint(session, &k);
 428                 if (ih < 0)
 429                         return ih;
 430
 431                 if (!ih) {
 432                         if (!idle_hint) {
 433                                 if (k.monotonic < ts.monotonic)
 434                                         ts = k;
 435                         } else {
 436                                 idle_hint = false;
 437                                 ts = k;
 438                         }
 439                 } else if (idle_hint) {
 440
 441                         if (k.monotonic > ts.monotonic)
 442                                 ts = k;
 443                 }
 444         }
 445
 446         if (t)
 447                 *t = ts;
 448
 449         return idle_hint;
 450 }
 451
 452 int seat_check_gc(Seat *s) {
 453         assert(s);
 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         return true;
 496 }