src/device.c

   1 /*-*- Mode: C; c-basic-offset: 8 -*-*/
   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 this is a different unit, then let's not merge things */
 192         if (u && DEVICE(u)->sysfs && !path_equal(DEVICE(u)->sysfs, sysfs)) {
 193                 log_error("Hmm, something's broken. Asked to create two devices with same name but different sysfs paths.");
 194                 return -EEXIST;
 195         }
 196
 197         if (!u) {
 198                 Device *first;
 199                 delete = true;
 200
 201                 if (!(u = unit_new(m)))
 202                         return -ENOMEM;
 203
 204                 if ((r = device_add_escaped_name(u, path)) < 0)
 205                         goto fail;
 206
 207                 if (!(DEVICE(u)->sysfs = strdup(sysfs))) {
 208                         r = -ENOMEM;
 209                         goto fail;
 210                 }
 211
 212                 unit_add_to_load_queue(u);
 213
 214                 if (!m->devices_by_sysfs)
 215                         if (!(m->devices_by_sysfs = hashmap_new(string_hash_func, string_compare_func))) {
 216                                 r = -ENOMEM;
 217                                 goto fail;
 218                         }
 219
 220                 first = hashmap_get(m->devices_by_sysfs, sysfs);
 221                 LIST_PREPEND(Device, same_sysfs, first, DEVICE(u));
 222
 223                 if ((r = hashmap_replace(m->devices_by_sysfs, DEVICE(u)->sysfs, first)) < 0)
 224                         goto fail;
 225
 226         } else
 227                 delete = false;
 228
 229         if ((model = udev_device_get_property_value(dev, "ID_MODEL_FROM_DATABASE")) ||
 230             (model = udev_device_get_property_value(dev, "ID_MODEL"))) {
 231                 if ((r = unit_set_description(u, model)) < 0)
 232                         goto fail;
 233         } else
 234                 if ((r = unit_set_description(u, path)) < 0)
 235                         goto fail;
 236
 237         if (main) {
 238                 /* The additional systemd udev properties we only
 239                  * interpret for the main object */
 240                 const char *wants, *alias;
 241
 242                 if ((alias = udev_device_get_property_value(dev, "SYSTEMD_ALIAS"))) {
 243                         if (!is_path(alias))
 244                                 log_warning("SYSTEMD_ALIAS for %s is not a path, ignoring: %s", sysfs, alias);
 245                         else {
 246                                 if ((r = device_add_escaped_name(u, alias)) < 0)
 247                                         goto fail;
 248                         }
 249                 }
 250
 251                 if ((wants = udev_device_get_property_value(dev, "SYSTEMD_WANTS"))) {
 252                         char *state, *w;
 253                         size_t l;
 254
 255                         FOREACH_WORD_QUOTED(w, l, wants, state) {
 256                                 char *e;
 257
 258                                 if (!(e = strndup(w, l))) {
 259                                         r = -ENOMEM;
 260                                         goto fail;
 261                                 }
 262
 263                                 r = unit_add_dependency_by_name(u, UNIT_WANTS, e, NULL, true);
 264                                 free(e);
 265
 266                                 if (r < 0)
 267                                         goto fail;
 268                         }
 269                 }
 270         }
 271
 272         unit_add_to_dbus_queue(u);
 273         return 0;
 274
 275 fail:
 276         log_warning("Failed to load device unit: %s", strerror(-r));
 277
 278         if (delete && u)
 279                 unit_free(u);
 280
 281         return r;
 282 }
 283
 284 static int device_process_new_device(Manager *m, struct udev_device *dev, bool update_state) {
 285         const char *sysfs, *dn;
 286         struct udev_list_entry *item = NULL, *first = NULL;
 287
 288         assert(m);
 289
 290         if (!(sysfs = udev_device_get_syspath(dev)))
 291                 return -ENOMEM;
 292
 293         /* Add the main unit named after the sysfs path */
 294         device_update_unit(m, dev, sysfs, true);
 295
 296         /* Add an additional unit for the device node */
 297         if ((dn = udev_device_get_devnode(dev)))
 298                 device_update_unit(m, dev, dn, false);
 299
 300         /* Add additional units for all symlinks */
 301         first = udev_device_get_devlinks_list_entry(dev);
 302         udev_list_entry_foreach(item, first) {
 303                 const char *p;
 304
 305                 /* Don't bother with the /dev/block links */
 306                 p = udev_list_entry_get_name(item);
 307
 308                 if (path_startswith(p, "/dev/block/") ||
 309                     path_startswith(p, "/dev/char/"))
 310                         continue;
 311
 312                 device_update_unit(m, dev, p, false);
 313         }
 314
 315         if (update_state) {
 316                 Device *d, *l;
 317
 318                 manager_dispatch_load_queue(m);
 319
 320                 l = hashmap_get(m->devices_by_sysfs, sysfs);
 321                 LIST_FOREACH(same_sysfs, d, l)
 322                         device_set_state(d, DEVICE_PLUGGED);
 323         }
 324
 325         return 0;
 326 }
 327
 328 static int device_process_path(Manager *m, const char *path, bool update_state) {
 329         int r;
 330         struct udev_device *dev;
 331
 332         assert(m);
 333         assert(path);
 334
 335         if (!(dev = udev_device_new_from_syspath(m->udev, path))) {
 336                 log_warning("Failed to get udev device object from udev for path %s.", path);
 337                 return -ENOMEM;
 338         }
 339
 340         r = device_process_new_device(m, dev, update_state);
 341         udev_device_unref(dev);
 342         return r;
 343 }
 344
 345 static int device_process_removed_device(Manager *m, struct udev_device *dev) {
 346         const char *sysfs;
 347         Device *d;
 348
 349         assert(m);
 350         assert(dev);
 351
 352         if (!(sysfs = udev_device_get_syspath(dev)))
 353                 return -ENOMEM;
 354
 355         /* Remove all units of this sysfs path */
 356         while ((d = hashmap_get(m->devices_by_sysfs, sysfs))) {
 357                 device_unset_sysfs(d);
 358                 device_set_state(d, DEVICE_DEAD);
 359         }
 360
 361         return 0;
 362 }
 363
 364 static Unit *device_following(Unit *u) {
 365         Device *d = DEVICE(u);
 366         Device *other, *first = NULL;
 367
 368         assert(d);
 369
 370         if (startswith(u->meta.id, "sys-"))
 371                 return NULL;
 372
 373         /* Make everybody follow the unit that's named after the sysfs path */
 374         for (other = d->same_sysfs_next; other; other = other->same_sysfs_next)
 375                 if (startswith(other->meta.id, "sys-"))
 376                         return UNIT(other);
 377
 378         for (other = d->same_sysfs_prev; other; other = other->same_sysfs_prev) {
 379                 if (startswith(other->meta.id, "sys-"))
 380                         return UNIT(other);
 381
 382                 first = other;
 383         }
 384
 385         return UNIT(first);
 386 }
 387
 388 static void device_shutdown(Manager *m) {
 389         assert(m);
 390
 391         if (m->udev_monitor) {
 392                 udev_monitor_unref(m->udev_monitor);
 393                 m->udev_monitor = NULL;
 394         }
 395
 396         if (m->udev) {
 397                 udev_unref(m->udev);
 398                 m->udev = NULL;
 399         }
 400
 401         hashmap_free(m->devices_by_sysfs);
 402         m->devices_by_sysfs = NULL;
 403 }
 404
 405 static int device_enumerate(Manager *m) {
 406         struct epoll_event ev;
 407         int r;
 408         struct udev_enumerate *e = NULL;
 409         struct udev_list_entry *item = NULL, *first = NULL;
 410
 411         assert(m);
 412
 413         if (!m->udev) {
 414                 if (!(m->udev = udev_new()))
 415                         return -ENOMEM;
 416
 417                 if (!(m->udev_monitor = udev_monitor_new_from_netlink(m->udev, "udev"))) {
 418                         r = -ENOMEM;
 419                         goto fail;
 420                 }
 421
 422                 if (udev_monitor_filter_add_match_tag(m->udev_monitor, "systemd") < 0) {
 423                         r = -ENOMEM;
 424                         goto fail;
 425                 }
 426
 427                 if (udev_monitor_enable_receiving(m->udev_monitor) < 0) {
 428                         r = -EIO;
 429                         goto fail;
 430                 }
 431
 432                 m->udev_watch.type = WATCH_UDEV;
 433                 m->udev_watch.fd = udev_monitor_get_fd(m->udev_monitor);
 434
 435                 zero(ev);
 436                 ev.events = EPOLLIN;
 437                 ev.data.ptr = &m->udev_watch;
 438
 439                 if (epoll_ctl(m->epoll_fd, EPOLL_CTL_ADD, m->udev_watch.fd, &ev) < 0)
 440                         return -errno;
 441         }
 442
 443         if (!(e = udev_enumerate_new(m->udev))) {
 444                 r = -ENOMEM;
 445                 goto fail;
 446         }
 447         if (udev_enumerate_add_match_tag(e, "systemd") < 0) {
 448                 r = -EIO;
 449                 goto fail;
 450         }
 451
 452         if (udev_enumerate_scan_devices(e) < 0) {
 453                 r = -EIO;
 454                 goto fail;
 455         }
 456
 457         first = udev_enumerate_get_list_entry(e);
 458         udev_list_entry_foreach(item, first)
 459                 device_process_path(m, udev_list_entry_get_name(item), false);
 460
 461         udev_enumerate_unref(e);
 462         return 0;
 463
 464 fail:
 465         if (e)
 466                 udev_enumerate_unref(e);
 467
 468         device_shutdown(m);
 469         return r;
 470 }
 471
 472 void device_fd_event(Manager *m, int events) {
 473         struct udev_device *dev;
 474         int r;
 475         const char *action;
 476
 477         assert(m);
 478         assert(events == EPOLLIN);
 479
 480         if (!(dev = udev_monitor_receive_device(m->udev_monitor))) {
 481                 log_error("Failed to receive device.");
 482                 return;
 483         }
 484
 485         if (!(action = udev_device_get_action(dev))) {
 486                 log_error("Failed to get udev action string.");
 487                 goto fail;
 488         }
 489
 490         if (streq(action, "remove")) {
 491                 if ((r = device_process_removed_device(m, dev)) < 0) {
 492                         log_error("Failed to process udev device event: %s", strerror(-r));
 493                         goto fail;
 494                 }
 495         } else {
 496                 if ((r = device_process_new_device(m, dev, true)) < 0) {
 497                         log_error("Failed to process udev device event: %s", strerror(-r));
 498                         goto fail;
 499                 }
 500         }
 501
 502 fail:
 503         udev_device_unref(dev);
 504 }
 505
 506 static const char* const device_state_table[_DEVICE_STATE_MAX] = {
 507         [DEVICE_DEAD] = "dead",
 508         [DEVICE_PLUGGED] = "plugged"
 509 };
 510
 511 DEFINE_STRING_TABLE_LOOKUP(device_state, DeviceState);
 512
 513 const UnitVTable device_vtable = {
 514         .suffix = ".device",
 515
 516         .no_requires = true,
 517         .no_instances = true,
 518         .no_snapshots = true,
 519         .no_isolate = true,
 520         .no_alias = true,
 521
 522         .init = device_init,
 523
 524         .load = unit_load_fragment_and_dropin_optional,
 525         .done = device_done,
 526         .coldplug = device_coldplug,
 527
 528         .dump = device_dump,
 529
 530         .active_state = device_active_state,
 531         .sub_state_to_string = device_sub_state_to_string,
 532
 533         .bus_message_handler = bus_device_message_handler,
 534
 535         .following = device_following,
 536
 537         .enumerate = device_enumerate,
 538         .shutdown = device_shutdown
 539 };