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 static int seat_preallocate_vts(Seat *s) {
 190         int r = 0;
 191         unsigned i;
 192
 193         assert(s);
 194         assert(s->manager);
 195
 196         if (s->manager->n_autovts <= 0)
 197                 return 0;
 198
 199         if (!seat_is_vtconsole(s))
 200                 return 0;
 201
 202         for (i = 1; i < s->manager->n_autovts; i++) {
 203                 int q;
 204
 205                 q = vt_allocate(i);
 206                 if (q < 0) {
 207                         log_error("Failed to preallocate VT %i: %s", i, strerror(-q));
 208                         r = q;
 209                 }
 210         }
 211
 212         return r;
 213 }
 214
 215 int seat_apply_acls(Seat *s, Session *old_active) {
 216         int r;
 217
 218         assert(s);
 219
 220         r = devnode_acl_all(s->manager->udev,
 221                             s->id,
 222                             false,
 223                             !!old_active, old_active ? old_active->user->uid : 0,
 224                             !!s->active, s->active ? s->active->user->uid : 0);
 225
 226         if (r < 0)
 227                 log_error("Failed to apply ACLs: %s", strerror(-r));
 228
 229         return r;
 230 }
 231
 232 int seat_set_active(Seat *s, Session *session) {
 233         Session *old_active;
 234
 235         assert(s);
 236         assert(!session || session->seat == s);
 237
 238         if (session == s->active)
 239                 return 0;
 240
 241         old_active = s->active;
 242         s->active = session;
 243
 244         seat_apply_acls(s, old_active);
 245
 246         if (session && session->started)
 247                 session_send_changed(session, "Active\0");
 248
 249         if (!session || session->started)
 250                 seat_send_changed(s, "ActiveSession\0");
 251
 252         seat_save(s);
 253
 254         if (session)
 255                 session_save(session);
 256
 257         if (old_active)
 258                 session_save(old_active);
 259
 260         return 0;
 261 }
 262
 263 int seat_active_vt_changed(Seat *s, int vtnr) {
 264         Session *i, *new_active = NULL;
 265         int r;
 266
 267         assert(s);
 268         assert(vtnr >= 1);
 269
 270         if (!seat_is_vtconsole(s))
 271                 return -EINVAL;
 272
 273         log_debug("VT changed to %i", vtnr);
 274
 275         LIST_FOREACH(sessions_by_seat, i, s->sessions)
 276                 if (i->vtnr == vtnr) {
 277                         new_active = i;
 278                         break;
 279                 }
 280
 281         r = seat_set_active(s, new_active);
 282         manager_spawn_autovt(s->manager, vtnr);
 283
 284         return r;
 285 }
 286
 287 int seat_read_active_vt(Seat *s) {
 288         char t[64];
 289         ssize_t k;
 290         int r, vtnr;
 291
 292         assert(s);
 293
 294         if (!seat_is_vtconsole(s))
 295                 return 0;
 296
 297         lseek(s->manager->console_active_fd, SEEK_SET, 0);
 298
 299         k = read(s->manager->console_active_fd, t, sizeof(t)-1);
 300         if (k <= 0) {
 301                 log_error("Failed to read current console: %s", k < 0 ? strerror(-errno) : "EOF");
 302                 return k < 0 ? -errno : -EIO;
 303         }
 304
 305         t[k] = 0;
 306         truncate_nl(t);
 307
 308         if (!startswith(t, "tty")) {
 309                 log_error("Hm, /sys/class/tty/tty0/active is badly formatted.");
 310                 return -EIO;
 311         }
 312
 313         r = safe_atoi(t+3, &vtnr);
 314         if (r < 0) {
 315                 log_error("Failed to parse VT number %s", t+3);
 316                 return r;
 317         }
 318
 319         if (vtnr <= 0) {
 320                 log_error("VT number invalid: %s", t+3);
 321                 return -EIO;
 322         }
 323
 324         return seat_active_vt_changed(s, vtnr);
 325 }
 326
 327 int seat_start(Seat *s) {
 328         assert(s);
 329
 330         if (s->started)
 331                 return 0;
 332
 333         log_info("New seat %s.", s->id);
 334
 335         /* Initialize VT magic stuff */
 336         seat_preallocate_vts(s);
 337
 338         /* Read current VT */
 339         seat_read_active_vt(s);
 340
 341         /* Save seat data */
 342         seat_save(s);
 343
 344         s->started = true;
 345
 346         seat_send_signal(s, true);
 347
 348         return 0;
 349 }
 350
 351 int seat_stop(Seat *s) {
 352         int r = 0;
 353
 354         assert(s);
 355
 356         if (s->started)
 357                 log_info("Removed seat %s.", s->id);
 358
 359         seat_stop_sessions(s);
 360
 361         unlink(s->state_file);
 362         seat_add_to_gc_queue(s);
 363
 364         if (s->started)
 365                 seat_send_signal(s, false);
 366
 367         s->started = false;
 368
 369         return r;
 370 }
 371
 372 int seat_stop_sessions(Seat *s) {
 373         Session *session;
 374         int r = 0, k;
 375
 376         assert(s);
 377
 378         LIST_FOREACH(sessions_by_seat, session, s->sessions) {
 379                 k = session_stop(session);
 380                 if (k < 0)
 381                         r = k;
 382         }
 383
 384         return r;
 385 }
 386
 387 int seat_attach_session(Seat *s, Session *session) {
 388         assert(s);
 389         assert(session);
 390         assert(!session->seat);
 391
 392         if (!seat_is_vtconsole(s) && s->sessions)
 393                 return -EEXIST;
 394
 395         session->seat = s;
 396         LIST_PREPEND(Session, sessions_by_seat, s->sessions, session);
 397
 398         seat_send_changed(s, "Sessions\0");
 399
 400         if (!seat_is_vtconsole(s)) {
 401                 assert(!s->active);
 402                 seat_set_active(s, session);
 403         }
 404
 405         return 0;
 406 }
 407
 408 bool seat_is_vtconsole(Seat *s) {
 409         assert(s);
 410
 411         return s->manager->vtconsole == s;
 412 }
 413
 414 int seat_get_idle_hint(Seat *s, dual_timestamp *t) {
 415         Session *session;
 416         bool idle_hint = true;
 417         dual_timestamp ts = { 0, 0 };
 418
 419         assert(s);
 420
 421         LIST_FOREACH(sessions_by_seat, session, s->sessions) {
 422                 dual_timestamp k;
 423                 int ih;
 424
 425                 ih = session_get_idle_hint(session, &k);
 426                 if (ih < 0)
 427                         return ih;
 428
 429                 if (!ih) {
 430                         if (!idle_hint) {
 431                                 if (k.monotonic < ts.monotonic)
 432                                         ts = k;
 433                         } else {
 434                                 idle_hint = false;
 435                                 ts = k;
 436                         }
 437                 } else if (idle_hint) {
 438
 439                         if (k.monotonic > ts.monotonic)
 440                                 ts = k;
 441                 }
 442         }
 443
 444         if (t)
 445                 *t = ts;
 446
 447         return idle_hint;
 448 }
 449
 450 int seat_check_gc(Seat *s) {
 451         assert(s);
 452
 453         if (seat_is_vtconsole(s))
 454                 return 1;
 455
 456         return !!s->devices;
 457 }
 458
 459 void seat_add_to_gc_queue(Seat *s) {
 460         assert(s);
 461
 462         if (s->in_gc_queue)
 463                 return;
 464
 465         LIST_PREPEND(Seat, gc_queue, s->manager->seat_gc_queue, s);
 466         s->in_gc_queue = true;
 467 }
 468
 469 static bool seat_name_valid_char(char c) {
 470         return
 471                 (c >= 'a' && c <= 'z') ||
 472                 (c >= 'A' && c <= 'Z') ||
 473                 (c >= '0' && c <= '9') ||
 474                 c == '-' ||
 475                 c == '_';
 476 }
 477
 478 bool seat_name_is_valid(const char *name) {
 479         const char *p;
 480
 481         assert(name);
 482
 483         if (!startswith(name, "seat"))
 484                 return false;
 485
 486         if (!name[4])
 487                 return false;
 488
 489         for (p = name; *p; p++)
 490                 if (!seat_name_valid_char(*p))
 491                         return false;
 492
 493         return true;
 494 }