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                 s->manager->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         return 0;
 162 }
 163
 164 static int vt_allocate(int vtnr) {
 165         int fd, r;
 166         char *p;
 167
 168         assert(vtnr >= 1);
 169
 170         if (asprintf(&p, "/dev/tty%i", vtnr) < 0)
 171                 return -ENOMEM;
 172
 173         fd = open_terminal(p, O_RDWR|O_NOCTTY|O_CLOEXEC);
 174         free(p);
 175
 176         r = fd < 0 ? -errno : 0;
 177
 178         if (fd >= 0)
 179                 close_nointr_nofail(fd);
 180
 181         return r;
 182 }
 183
 184 static int seat_preallocate_vts(Seat *s) {
 185         int i, r = 0;
 186
 187         assert(s);
 188         assert(s->manager);
 189
 190         if (s->manager->n_autovts <= 0)
 191                 return 0;
 192
 193         if (s->manager->vtconsole != s)
 194                 return 0;
 195
 196         for (i = 1; i < s->manager->n_autovts; i++) {
 197                 int q;
 198
 199                 q = vt_allocate(i);
 200                 if (q < 0) {
 201                         log_error("Failed to preallocate VT %i: %s", i, strerror(-q));
 202                         r = q;
 203                 }
 204         }
 205
 206         return r;
 207 }
 208
 209 int seat_apply_acls(Seat *s, Session *old_active) {
 210         int r;
 211
 212         assert(s);
 213
 214         r = devnode_acl_all(s->manager->udev,
 215                             s->id,
 216                             false,
 217                             !!old_active, old_active ? old_active->user->uid : 0,
 218                             !!s->active, s->active ? s->active->user->uid : 0);
 219
 220         if (r < 0)
 221                 log_error("Failed to apply ACLs: %s", strerror(-r));
 222
 223         return r;
 224 }
 225
 226 int seat_active_vt_changed(Seat *s, int vtnr) {
 227         Session *i, *new_active = NULL, *old_active;
 228
 229         assert(s);
 230         assert(vtnr >= 1);
 231
 232         if (s->manager->vtconsole != s)
 233                 return -EINVAL;
 234
 235         log_debug("VT changed to %i", vtnr);
 236
 237         LIST_FOREACH(sessions_by_seat, i, s->sessions)
 238                 if (i->vtnr == vtnr) {
 239                         new_active = i;
 240                         break;
 241                 }
 242
 243         if (new_active == s->active)
 244                 return 0;
 245
 246         old_active = s->active;
 247         s->active = new_active;
 248
 249         seat_apply_acls(s, old_active);
 250         manager_spawn_autovt(s->manager, vtnr);
 251
 252         return 0;
 253 }
 254
 255 int seat_read_active_vt(Seat *s) {
 256         char t[64];
 257         ssize_t k;
 258         int r, vtnr;
 259
 260         assert(s);
 261
 262         if (s->manager->vtconsole != s)
 263                 return 0;
 264
 265         lseek(s->manager->console_active_fd, SEEK_SET, 0);
 266
 267         k = read(s->manager->console_active_fd, t, sizeof(t)-1);
 268         if (k <= 0) {
 269                 log_error("Failed to read current console: %s", k < 0 ? strerror(-errno) : "EOF");
 270                 return k < 0 ? -errno : -EIO;
 271         }
 272
 273         t[k] = 0;
 274         truncate_nl(t);
 275
 276         if (!startswith(t, "tty")) {
 277                 log_error("Hm, /sys/class/tty/tty0/active is badly formatted.");
 278                 return -EIO;
 279         }
 280
 281         r = safe_atoi(t+3, &vtnr);
 282         if (r < 0) {
 283                 log_error("Failed to parse VT number %s", t+3);
 284                 return r;
 285         }
 286
 287         if (vtnr <= 0) {
 288                 log_error("VT number invalid: %s", t+3);
 289                 return -EIO;
 290         }
 291
 292         return seat_active_vt_changed(s, vtnr);
 293 }
 294
 295 int seat_start(Seat *s) {
 296         assert(s);
 297
 298         /* Initialize VT magic stuff */
 299         seat_preallocate_vts(s);
 300
 301         /* Read current VT */
 302         seat_read_active_vt(s);
 303
 304         /* Save seat data */
 305         seat_save(s);
 306
 307         return 0;
 308 }
 309
 310 int seat_stop(Seat *s) {
 311         Session *session;
 312         int r = 0, k;
 313
 314         assert(s);
 315
 316         LIST_FOREACH(sessions_by_seat, session, s->sessions) {
 317                 k = session_stop(session);
 318                 if (k < 0)
 319                         r = k;
 320         }
 321
 322         unlink(s->state_file);
 323         seat_add_to_gc_queue(s);
 324
 325         return r;
 326 }
 327
 328 int seat_check_gc(Seat *s) {
 329         assert(s);
 330
 331         if (s->manager->vtconsole == s)
 332                 return 1;
 333
 334         return !!s->devices;
 335 }
 336
 337 void seat_add_to_gc_queue(Seat *s) {
 338         assert(s);
 339
 340         if (s->in_gc_queue)
 341                 return;
 342
 343         LIST_PREPEND(Seat, gc_queue, s->manager->seat_gc_queue, s);
 344         s->in_gc_queue = true;
 345 }