src/device.c

   1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
   2
   3 /***
   4   This file is part of systemd.
   5
   6   Copyright 2010 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 <errno.h>
  23 #include <sys/epoll.h>
  24 #include <libudev.h>
  25
  26 #include "unit.h"
  27 #include "device.h"
  28 #include "strv.h"
  29 #include "log.h"
  30 #include "unit-name.h"
  31 #include "dbus-device.h"
  32
  33 static const UnitActiveState state_translation_table[_DEVICE_STATE_MAX] = {
  34         [DEVICE_DEAD] = UNIT_INACTIVE,
  35         [DEVICE_PLUGGED] = UNIT_ACTIVE
  36 };
  37
  38 static void device_unset_sysfs(Device *d) {
  39         Device *first;
  40
  41         assert(d);
  42
  43         if (!d->sysfs)
  44                 return;
  45
  46         /* Remove this unit from the chain of devices which share the
  47          * same sysfs path. */
  48         first = hashmap_get(d->meta.manager->devices_by_sysfs, d->sysfs);
  49         LIST_REMOVE(Device, same_sysfs, first, d);
  50
  51         if (first)
  52                 hashmap_remove_and_replace(d->meta.manager->devices_by_sysfs, d->sysfs, first->sysfs, first);
  53         else
  54                 hashmap_remove(d->meta.manager->devices_by_sysfs, d->sysfs);
  55
  56         free(d->sysfs);
  57         d->sysfs = NULL;
  58 }
  59
  60 static void device_init(Unit *u) {
  61         Device *d = DEVICE(u);
  62
  63         assert(d);
  64         assert(d->meta.load_state == UNIT_STUB);
  65
  66         /* In contrast to all other unit types we timeout jobs waiting
  67          * for devices by default. This is because they otherwise wait
  68          * indefinetely for plugged in devices, something which cannot
  69          * happen for the other units since their operations time out
  70          * anyway. */
  71         d->meta.job_timeout = DEFAULT_TIMEOUT_USEC;
  72 }
  73
  74 static void device_done(Unit *u) {
  75         Device *d = DEVICE(u);
  76
  77         assert(d);
  78
  79         device_unset_sysfs(d);
  80 }
  81
  82 static void device_set_state(Device *d, DeviceState state) {
  83         DeviceState old_state;
  84         assert(d);
  85
  86         old_state = d->state;
  87         d->state = state;
  88
  89         if (state != old_state)
  90                 log_debug("%s changed %s -> %s",
  91                           d->meta.id,
  92                           device_state_to_string(old_state),
  93                           device_state_to_string(state));
  94
  95         unit_notify(UNIT(d), state_translation_table[old_state], state_translation_table[state]);
  96 }
  97
  98 static int device_coldplug(Unit *u) {
  99         Device *d = DEVICE(u);
 100
 101         assert(d);
 102         assert(d->state == DEVICE_DEAD);
 103
 104         if (d->sysfs)
 105                 device_set_state(d, DEVICE_PLUGGED);
 106
 107         return 0;
 108 }
 109
 110 static void device_dump(Unit *u, FILE *f, const char *prefix) {
 111         Device *d = DEVICE(u);
 112
 113         assert(d);
 114
 115         fprintf(f,
 116                 "%sDevice State: %s\n"
 117                 "%sSysfs Path: %s\n",
 118                 prefix, device_state_to_string(d->state),
 119                 prefix, strna(d->sysfs));
 120 }
 121
 122 static UnitActiveState device_active_state(Unit *u) {
 123         assert(u);
 124
 125         return state_translation_table[DEVICE(u)->state];
 126 }
 127
 128 static const char *device_sub_state_to_string(Unit *u) {
 129         assert(u);
 130
 131         return device_state_to_string(DEVICE(u)->state);
 132 }
 133
 134 static int device_add_escaped_name(Unit *u, const char *dn) {
 135         char *e;
 136         int r;
 137
 138         assert(u);
 139         assert(dn);
 140         assert(dn[0] == '/');
 141
 142         if (!(e = unit_name_from_path(dn, ".device")))
 143                 return -ENOMEM;
 144
 145         r = unit_add_name(u, e);
 146         free(e);
 147
 148         if (r < 0 && r != -EEXIST)
 149                 return r;
 150
 151         return 0;
 152 }
 153
 154 static int device_find_escape_name(Manager *m, const char *dn, Unit **_u) {
 155         char *e;
 156         Unit *u;
 157
 158         assert(m);
 159         assert(dn);
 160         assert(dn[0] == '/');
 161         assert(_u);
 162
 163         if (!(e = unit_name_from_path(dn, ".device")))
 164                 return -ENOMEM;
 165
 166         u = manager_get_unit(m, e);
 167         free(e);
 168
 169         if (u) {
 170                 *_u = u;
 171                 return 1;
 172         }
 173
 174         return 0;
 175 }
 176
 177 static int device_update_unit(Manager *m, struct udev_device *dev, const char *path, bool main) {
 178         const char *sysfs, *model;
 179         Unit *u = NULL;
 180         int r;
 181         bool delete;
 182
 183         assert(m);
 184
 185         if (!(sysfs = udev_device_get_syspath(dev)))
 186                 return -ENOMEM;
 187
 188         if ((r = device_find_escape_name(m, path, &u)) < 0)
 189                 return r;
 190
 191         if (u && DEVICE(u)->sysfs && !path_equal(DEVICE(u)->sysfs, sysfs))
 192                 return -EEXIST;
 193
 194         if (!u) {
 195                 delete = true;
 196
 197                 if (!(u = unit_new(m)))
 198                         return -ENOMEM;
 199
 200                 if ((r = device_add_escaped_name(u, path)) < 0)
 201                         goto fail;
 202
 203                 unit_add_to_load_queue(u);
 204         } else
 205                 delete = false;
 206
 207         /* If this was created via some dependency and has not
 208          * actually been seen yet ->sysfs will not be
 209          * initialized. Hence initialize it if necessary. */
 210
 211         if (!DEVICE(u)->sysfs) {
 212                 Device *first;
 213
 214                 if (!(DEVICE(u)->sysfs = strdup(sysfs))) {
 215                         r = -ENOMEM;
 216                         goto fail;
 217                 }
 218
 219                 if (!m->devices_by_sysfs)
 220                         if (!(m->devices_by_sysfs = hashmap_new(string_hash_func, string_compare_func))) {
 221                                 r = -ENOMEM;
 222                                 goto fail;
 223                         }
 224
 225                 first = hashmap_get(m->devices_by_sysfs, sysfs);
 226                 LIST_PREPEND(Device, same_sysfs, first, DEVICE(u));
 227
 228                 if ((r = hashmap_replace(m->devices_by_sysfs, DEVICE(u)->sysfs, first)) < 0)
 229                         goto fail;
 230         }
 231
 232         if ((model = udev_device_get_property_value(dev, "ID_MODEL_FROM_DATABASE")) ||
 233             (model = udev_device_get_property_value(dev, "ID_MODEL"))) {
 234                 if ((r = unit_set_description(u, model)) < 0)
 235                         goto fail;
 236         } else
 237                 if ((r = unit_set_description(u, path)) < 0)
 238                         goto fail;
 239
 240         if (main) {
 241                 /* The additional systemd udev properties we only
 242                  * interpret for the main object */
 243                 const char *wants, *alias;
 244
 245                 if ((alias = udev_device_get_property_value(dev, "SYSTEMD_ALIAS"))) {
 246                         if (!is_path(alias))
 247                                 log_warning("SYSTEMD_ALIAS for %s is not a path, ignoring: %s", sysfs, alias);
 248                         else {
 249                                 if ((r = device_add_escaped_name(u, alias)) < 0)
 250                                         goto fail;
 251                         }
 252                 }
 253
 254                 if ((wants = udev_device_get_property_value(dev, "SYSTEMD_WANTS"))) {
 255                         char *state, *w;
 256                         size_t l;
 257
 258                         FOREACH_WORD_QUOTED(w, l, wants, state) {
 259                                 char *e;
 260
 261                                 if (!(e = strndup(w, l))) {
 262                                         r = -ENOMEM;
 263                                         goto fail;
 264                                 }
 265
 266                                 r = unit_add_dependency_by_name(u, UNIT_WANTS, e, NULL, true);
 267                                 free(e);
 268
 269                                 if (r < 0)
 270                                         goto fail;
 271                         }
 272                 }
 273         }
 274
 275         unit_add_to_dbus_queue(u);
 276         return 0;
 277
 278 fail:
 279         log_warning("Failed to load device unit: %s", strerror(-r));
 280
 281         if (delete && u)
 282                 unit_free(u);
 283
 284         return r;
 285 }
 286
 287 static int device_process_new_device(Manager *m, struct udev_device *dev, bool update_state) {
 288         const char *sysfs, *dn;
 289         struct udev_list_entry *item = NULL, *first = NULL;
 290
 291         assert(m);
 292
 293         if (!(sysfs = udev_device_get_syspath(dev)))
 294                 return -ENOMEM;
 295
 296         /* Add the main unit named after the sysfs path */
 297         device_update_unit(m, dev, sysfs, true);
 298
 299         /* Add an additional unit for the device node */
 300         if ((dn = udev_device_get_devnode(dev)))
 301                 device_update_unit(m, dev, dn, false);
 302
 303         /* Add additional units for all symlinks */
 304         first = udev_device_get_devlinks_list_entry(dev);
 305         udev_list_entry_foreach(item, first) {
 306                 const char *p;
 307                 struct stat st;
 308
 309                 /* Don't bother with the /dev/block links */
 310                 p = udev_list_entry_get_name(item);
 311
 312                 if (path_startswith(p, "/dev/block/") ||
 313                     path_startswith(p, "/dev/char/"))
 314                         continue;
 315
 316                 /* Verify that the symlink in the FS actually belongs
 317                  * to this device. This is useful to deal with
 318                  * conflicting devices, e.g. when two disks want the
 319                  * same /dev/disk/by-label/xxx link because they have
 320                  * the same label. We want to make sure that the same
 321                  * device that won the symlink wins in systemd, so we
 322                  * check the device node major/minor*/
 323                 if (stat(p, &st) >= 0)
 324                         if ((!S_ISBLK(st.st_mode) && !S_ISCHR(st.st_mode)) ||
 325                             st.st_rdev != udev_device_get_devnum(dev))
 326                                 continue;
 327
 328                 device_update_unit(m, dev, p, false);
 329         }
 330
 331         if (update_state) {
 332                 Device *d, *l;
 333
 334                 manager_dispatch_load_queue(m);
 335
 336                 l = hashmap_get(m->devices_by_sysfs, sysfs);
 337                 LIST_FOREACH(same_sysfs, d, l)
 338                         device_set_state(d, DEVICE_PLUGGED);
 339         }
 340
 341         return 0;
 342 }
 343
 344 static int device_process_path(Manager *m, const char *path, bool update_state) {
 345         int r;
 346         struct udev_device *dev;
 347
 348         assert(m);
 349         assert(path);
 350
 351         if (!(dev = udev_device_new_from_syspath(m->udev, path))) {
 352                 log_warning("Failed to get udev device object from udev for path %s.", path);
 353                 return -ENOMEM;
 354         }
 355
 356         r = device_process_new_device(m, dev, update_state);
 357         udev_device_unref(dev);
 358         return r;
 359 }
 360
 361 static int device_process_removed_device(Manager *m, struct udev_device *dev) {
 362         const char *sysfs;
 363         Device *d;
 364
 365         assert(m);
 366         assert(dev);
 367
 368         if (!(sysfs = udev_device_get_syspath(dev)))
 369                 return -ENOMEM;
 370
 371         /* Remove all units of this sysfs path */
 372         while ((d = hashmap_get(m->devices_by_sysfs, sysfs))) {
 373                 device_unset_sysfs(d);
 374                 device_set_state(d, DEVICE_DEAD);
 375         }
 376
 377         return 0;
 378 }
 379
 380 static Unit *device_following(Unit *u) {
 381         Device *d = DEVICE(u);
 382         Device *other, *first = NULL;
 383
 384         assert(d);
 385
 386         if (startswith(u->meta.id, "sys-"))
 387                 return NULL;
 388
 389         /* Make everybody follow the unit that's named after the sysfs path */
 390         for (other = d->same_sysfs_next; other; other = other->same_sysfs_next)
 391                 if (startswith(other->meta.id, "sys-"))
 392                         return UNIT(other);
 393
 394         for (other = d->same_sysfs_prev; other; other = other->same_sysfs_prev) {
 395                 if (startswith(other->meta.id, "sys-"))
 396                         return UNIT(other);
 397
 398                 first = other;
 399         }
 400
 401         return UNIT(first);
 402 }
 403
 404 static void device_shutdown(Manager *m) {
 405         assert(m);
 406
 407         if (m->udev_monitor) {
 408                 udev_monitor_unref(m->udev_monitor);
 409                 m->udev_monitor = NULL;
 410         }
 411
 412         if (m->udev) {
 413                 udev_unref(m->udev);
 414                 m->udev = NULL;
 415         }
 416
 417         hashmap_free(m->devices_by_sysfs);
 418         m->devices_by_sysfs = NULL;
 419 }
 420
 421 static int device_enumerate(Manager *m) {
 422         struct epoll_event ev;
 423         int r;
 424         struct udev_enumerate *e = NULL;
 425         struct udev_list_entry *item = NULL, *first = NULL;
 426
 427         assert(m);
 428
 429         if (!m->udev) {
 430                 if (!(m->udev = udev_new()))
 431                         return -ENOMEM;
 432
 433                 if (!(m->udev_monitor = udev_monitor_new_from_netlink(m->udev, "udev"))) {
 434                         r = -ENOMEM;
 435                         goto fail;
 436                 }
 437
 438                 if (udev_monitor_filter_add_match_tag(m->udev_monitor, "systemd") < 0) {
 439                         r = -ENOMEM;
 440                         goto fail;
 441                 }
 442
 443                 if (udev_monitor_enable_receiving(m->udev_monitor) < 0) {
 444                         r = -EIO;
 445                         goto fail;
 446                 }
 447
 448                 m->udev_watch.type = WATCH_UDEV;
 449                 m->udev_watch.fd = udev_monitor_get_fd(m->udev_monitor);
 450
 451                 zero(ev);
 452                 ev.events = EPOLLIN;
 453                 ev.data.ptr = &m->udev_watch;
 454
 455                 if (epoll_ctl(m->epoll_fd, EPOLL_CTL_ADD, m->udev_watch.fd, &ev) < 0)
 456                         return -errno;
 457         }
 458
 459         if (!(e = udev_enumerate_new(m->udev))) {
 460                 r = -ENOMEM;
 461                 goto fail;
 462         }
 463         if (udev_enumerate_add_match_tag(e, "systemd") < 0) {
 464                 r = -EIO;
 465                 goto fail;
 466         }
 467
 468         if (udev_enumerate_scan_devices(e) < 0) {
 469                 r = -EIO;
 470                 goto fail;
 471         }
 472
 473         first = udev_enumerate_get_list_entry(e);
 474         udev_list_entry_foreach(item, first)
 475                 device_process_path(m, udev_list_entry_get_name(item), false);
 476
 477         udev_enumerate_unref(e);
 478         return 0;
 479
 480 fail:
 481         if (e)
 482                 udev_enumerate_unref(e);
 483
 484         device_shutdown(m);
 485         return r;
 486 }
 487
 488 void device_fd_event(Manager *m, int events) {
 489         struct udev_device *dev;
 490         int r;
 491         const char *action;
 492
 493         assert(m);
 494         assert(events == EPOLLIN);
 495
 496         if (!(dev = udev_monitor_receive_device(m->udev_monitor))) {
 497                 log_error("Failed to receive device.");
 498                 return;
 499         }
 500
 501         if (!(action = udev_device_get_action(dev))) {
 502                 log_error("Failed to get udev action string.");
 503                 goto fail;
 504         }
 505
 506         if (streq(action, "remove")) {
 507                 if ((r = device_process_removed_device(m, dev)) < 0) {
 508                         log_error("Failed to process udev device event: %s", strerror(-r));
 509                         goto fail;
 510                 }
 511         } else {
 512                 if ((r = device_process_new_device(m, dev, true)) < 0) {
 513                         log_error("Failed to process udev device event: %s", strerror(-r));
 514                         goto fail;
 515                 }
 516         }
 517
 518 fail:
 519         udev_device_unref(dev);
 520 }
 521
 522 static const char* const device_state_table[_DEVICE_STATE_MAX] = {
 523         [DEVICE_DEAD] = "dead",
 524         [DEVICE_PLUGGED] = "plugged"
 525 };
 526
 527 DEFINE_STRING_TABLE_LOOKUP(device_state, DeviceState);
 528
 529 const UnitVTable device_vtable = {
 530         .suffix = ".device",
 531
 532         .no_requires = true,
 533         .no_instances = true,
 534         .no_snapshots = true,
 535         .no_isolate = true,
 536
 537         .init = device_init,
 538
 539         .load = unit_load_fragment_and_dropin_optional,
 540         .done = device_done,
 541         .coldplug = device_coldplug,
 542
 543         .dump = device_dump,
 544
 545         .active_state = device_active_state,
 546         .sub_state_to_string = device_sub_state_to_string,
 547
 548         .bus_interface = "org.freedesktop.systemd1.Device",
 549         .bus_message_handler = bus_device_message_handler,
 550         .bus_invalidating_properties =  bus_device_invalidating_properties,
 551
 552         .following = device_following,
 553
 554         .enumerate = device_enumerate,
 555         .shutdown = device_shutdown
 556 };