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         if (s->state_file) {
  79                 unlink(s->state_file);
  80                 free(s->state_file);
  81         }
  82
  83         free(s);
  84 }
  85
  86 int seat_save(Seat *s) {
  87         int r;
  88         FILE *f;
  89         char *temp_path;
  90
  91         assert(s);
  92
  93         r = safe_mkdir("/run/systemd/seat", 0755, 0, 0);
  94         if (r < 0)
  95                 goto finish;
  96
  97         r = fopen_temporary(s->state_file, &f, &temp_path);
  98         if (r < 0)
  99                 goto finish;
 100
 101         fchmod(fileno(f), 0644);
 102
 103         fprintf(f,
 104                 "# This is private data. Do not parse.\n"
 105                 "IS_VTCONSOLE=%i\n",
 106                 s->manager->vtconsole == s);
 107
 108         if (s->active) {
 109                 assert(s->active->user);
 110
 111                 fprintf(f,
 112                         "ACTIVE=%s\n"
 113                         "ACTIVE_UID=%lu\n",
 114                         s->active->id,
 115                         (unsigned long) s->active->user->uid);
 116         }
 117
 118         if (s->sessions) {
 119                 Session *i;
 120
 121                 fputs("OTHER=", f);
 122                 LIST_FOREACH(sessions_by_seat, i, s->sessions) {
 123                         if (i == s->active)
 124                                 continue;
 125
 126                         fprintf(f,
 127                                 "%s%c",
 128                                 i->id,
 129                                 i->sessions_by_seat_next ? ' ' : '\n');
 130                 }
 131
 132                 fputs("OTHER_UIDS=", f);
 133                 LIST_FOREACH(sessions_by_seat, i, s->sessions) {
 134                         if (i == s->active)
 135                                 continue;
 136
 137                         fprintf(f,
 138                                 "%lu%c",
 139                                 (unsigned long) i->user->uid,
 140                                 i->sessions_by_seat_next ? ' ' : '\n');
 141                 }
 142         }
 143
 144         fflush(f);
 145
 146         if (ferror(f) || rename(temp_path, s->state_file) < 0) {
 147                 r = -errno;
 148                 unlink(s->state_file);
 149                 unlink(temp_path);
 150         }
 151
 152         fclose(f);
 153         free(temp_path);
 154
 155 finish:
 156         if (r < 0)
 157                 log_error("Failed to save seat data for %s: %s", s->id, strerror(-r));
 158
 159         return r;
 160 }
 161
 162 int seat_load(Seat *s) {
 163         assert(s);
 164
 165         return 0;
 166 }
 167
 168 static int vt_allocate(int vtnr) {
 169         int fd, r;
 170         char *p;
 171
 172         assert(vtnr >= 1);
 173
 174         if (asprintf(&p, "/dev/tty%i", vtnr) < 0)
 175                 return -ENOMEM;
 176
 177         fd = open_terminal(p, O_RDWR|O_NOCTTY|O_CLOEXEC);
 178         free(p);
 179
 180         r = fd < 0 ? -errno : 0;
 181
 182         if (fd >= 0)
 183                 close_nointr_nofail(fd);
 184
 185         return r;
 186 }
 187
 188 static int seat_preallocate_vts(Seat *s) {
 189         int i, r = 0;
 190
 191         assert(s);
 192         assert(s->manager);
 193
 194         if (s->manager->n_autovts <= 0)
 195                 return 0;
 196
 197         if (s->manager->vtconsole != s)
 198                 return 0;
 199
 200         for (i = 1; i < s->manager->n_autovts; i++) {
 201                 int q;
 202
 203                 q = vt_allocate(i);
 204                 if (q < 0) {
 205                         log_error("Failed to preallocate VT %i: %s", i, strerror(-q));
 206                         r = q;
 207                 }
 208         }
 209
 210         return r;
 211 }
 212
 213 int seat_apply_acls(Seat *s, Session *old_active) {
 214         int r;
 215
 216         assert(s);
 217
 218         r = devnode_acl_all(s->manager->udev,
 219                             s->id,
 220                             false,
 221                             !!old_active, old_active ? old_active->user->uid : 0,
 222                             !!s->active, s->active ? s->active->user->uid : 0);
 223
 224         if (r < 0)
 225                 log_error("Failed to apply ACLs: %s", strerror(-r));
 226
 227         return r;
 228 }
 229
 230 int seat_active_vt_changed(Seat *s, int vtnr) {
 231         Session *i, *new_active = NULL, *old_active;
 232
 233         assert(s);
 234         assert(vtnr >= 1);
 235
 236         if (s->manager->vtconsole != s)
 237                 return -EINVAL;
 238
 239         log_debug("VT changed to %i", vtnr);
 240
 241         LIST_FOREACH(sessions_by_seat, i, s->sessions)
 242                 if (i->vtnr == vtnr) {
 243                         new_active = i;
 244                         break;
 245                 }
 246
 247         if (new_active == s->active)
 248                 return 0;
 249
 250         old_active = s->active;
 251         s->active = new_active;
 252
 253         seat_apply_acls(s, old_active);
 254         manager_spawn_autovt(s->manager, vtnr);
 255
 256         return 0;
 257 }
 258
 259 int seat_read_active_vt(Seat *s) {
 260         char t[64];
 261         ssize_t k;
 262         int r, vtnr;
 263
 264         assert(s);
 265
 266         if (s->manager->vtconsole != s)
 267                 return 0;
 268
 269         lseek(s->manager->console_active_fd, SEEK_SET, 0);
 270
 271         k = read(s->manager->console_active_fd, t, sizeof(t)-1);
 272         if (k <= 0) {
 273                 log_error("Failed to read current console: %s", k < 0 ? strerror(-errno) : "EOF");
 274                 return k < 0 ? -errno : -EIO;
 275         }
 276
 277         t[k] = 0;
 278         truncate_nl(t);
 279
 280         if (!startswith(t, "tty")) {
 281                 log_error("Hm, /sys/class/tty/tty0/active is badly formatted.");
 282                 return -EIO;
 283         }
 284
 285         r = safe_atoi(t+3, &vtnr);
 286         if (r < 0) {
 287                 log_error("Failed to parse VT number %s", t+3);
 288                 return r;
 289         }
 290
 291         if (vtnr <= 0) {
 292                 log_error("VT number invalid: %s", t+3);
 293                 return -EIO;
 294         }
 295
 296         return seat_active_vt_changed(s, vtnr);
 297 }
 298
 299 int seat_start(Seat *s) {
 300         assert(s);
 301
 302         /* Initialize VT magic stuff */
 303         seat_preallocate_vts(s);
 304
 305         /* Read current VT */
 306         seat_read_active_vt(s);
 307
 308         /* Save seat data */
 309         seat_save(s);
 310
 311         return 0;
 312 }
 313
 314 int seat_stop(Seat *s) {
 315         Session *session;
 316         int r = 0, k;
 317
 318         assert(s);
 319
 320         LIST_FOREACH(sessions_by_seat, session, s->sessions) {
 321                 k = session_stop(session);
 322                 if (k < 0)
 323                         r = k;
 324         }
 325
 326         seat_save(s);
 327         seat_add_to_gc_queue(s);
 328
 329         return r;
 330 }
 331
 332 int seat_check_gc(Seat *s) {
 333         assert(s);
 334
 335         if (s->manager->vtconsole == s)
 336                 return 1;
 337
 338         return !!s->devices;
 339 }
 340
 341 void seat_add_to_gc_queue(Seat *s) {
 342         assert(s);
 343
 344         if (s->in_gc_queue)
 345                 return;
 346
 347         LIST_PREPEND(Seat, gc_queue, s->manager->seat_gc_queue, s);
 348         s->in_gc_queue = true;
 349 }