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