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 #include "def.h"
  33
  34 static const UnitActiveState state_translation_table[_DEVICE_STATE_MAX] = {
  35         [DEVICE_DEAD] = UNIT_INACTIVE,
  36         [DEVICE_PLUGGED] = UNIT_ACTIVE
  37 };
  38
  39 static void device_unset_sysfs(Device *d) {
  40         Device *first;
  41
  42         assert(d);
  43
  44         if (!d->sysfs)
  45                 return;
  46
  47         /* Remove this unit from the chain of devices which share the
  48          * same sysfs path. */
  49         first = hashmap_get(UNIT(d)->manager->devices_by_sysfs, d->sysfs);
  50         LIST_REMOVE(Device, same_sysfs, first, d);
  51
  52         if (first)
  53                 hashmap_remove_and_replace(UNIT(d)->manager->devices_by_sysfs, d->sysfs, first->sysfs, first);
  54         else
  55                 hashmap_remove(UNIT(d)->manager->devices_by_sysfs, d->sysfs);
  56
  57         free(d->sysfs);
  58         d->sysfs = NULL;
  59 }
  60
  61 static void device_init(Unit *u) {
  62         Device *d = DEVICE(u);
  63
  64         assert(d);
  65         assert(UNIT(d)->load_state == UNIT_STUB);
  66
  67         /* In contrast to all other unit types we timeout jobs waiting
  68          * for devices by default. This is because they otherwise wait
  69          * indefinitely for plugged in devices, something which cannot
  70          * happen for the other units since their operations time out
  71          * anyway. */
  72         UNIT(d)->job_timeout = DEFAULT_TIMEOUT_USEC;
  73
  74         UNIT(d)->ignore_on_isolate = true;
  75         UNIT(d)->ignore_on_snapshot = true;
  76 }
  77
  78 static void device_done(Unit *u) {
  79         Device *d = DEVICE(u);
  80
  81         assert(d);
  82
  83         device_unset_sysfs(d);
  84 }
  85
  86 static void device_set_state(Device *d, DeviceState state) {
  87         DeviceState old_state;
  88         assert(d);
  89
  90         old_state = d->state;
  91         d->state = state;
  92
  93         if (state != old_state)
  94                 log_debug("%s changed %s -> %s",
  95                           UNIT(d)->id,
  96                           device_state_to_string(old_state),
  97                           device_state_to_string(state));
  98
  99         unit_notify(UNIT(d), state_translation_table[old_state], state_translation_table[state], true);
 100 }
 101
 102 static int device_coldplug(Unit *u) {
 103         Device *d = DEVICE(u);
 104
 105         assert(d);
 106         assert(d->state == DEVICE_DEAD);
 107
 108         if (d->sysfs)
 109                 device_set_state(d, DEVICE_PLUGGED);
 110
 111         return 0;
 112 }
 113
 114 static void device_dump(Unit *u, FILE *f, const char *prefix) {
 115         Device *d = DEVICE(u);
 116
 117         assert(d);
 118
 119         fprintf(f,
 120                 "%sDevice State: %s\n"
 121                 "%sSysfs Path: %s\n",
 122                 prefix, device_state_to_string(d->state),
 123                 prefix, strna(d->sysfs));
 124 }
 125
 126 static UnitActiveState device_active_state(Unit *u) {
 127         assert(u);
 128
 129         return state_translation_table[DEVICE(u)->state];
 130 }
 131
 132 static const char *device_sub_state_to_string(Unit *u) {
 133         assert(u);
 134
 135         return device_state_to_string(DEVICE(u)->state);
 136 }
 137
 138 static int device_add_escaped_name(Unit *u, const char *dn) {
 139         char *e;
 140         int r;
 141
 142         assert(u);
 143         assert(dn);
 144         assert(dn[0] == '/');
 145
 146         if (!(e = unit_name_from_path(dn, ".device")))
 147                 return -ENOMEM;
 148
 149         r = unit_add_name(u, e);
 150         free(e);
 151
 152         if (r < 0 && r != -EEXIST)
 153                 return r;
 154
 155         return 0;
 156 }
 157
 158 static int device_find_escape_name(Manager *m, const char *dn, Unit **_u) {
 159         char *e;
 160         Unit *u;
 161
 162         assert(m);
 163         assert(dn);
 164         assert(dn[0] == '/');
 165         assert(_u);
 166
 167         if (!(e = unit_name_from_path(dn, ".device")))
 168                 return -ENOMEM;
 169
 170         u = manager_get_unit(m, e);
 171         free(e);
 172
 173         if (u) {
 174                 *_u = u;
 175                 return 1;
 176         }
 177
 178         return 0;
 179 }
 180
 181 static int device_update_unit(Manager *m, struct udev_device *dev, const char *path, bool main) {
 182         const char *sysfs, *model;
 183         Unit *u = NULL;
 184         int r;
 185         bool delete;
 186
 187         assert(m);
 188
 189         if (!(sysfs = udev_device_get_syspath(dev)))
 190                 return -ENOMEM;
 191
 192         if ((r = device_find_escape_name(m, path, &u)) < 0)
 193                 return r;
 194
 195         if (u && DEVICE(u)->sysfs && !path_equal(DEVICE(u)->sysfs, sysfs))
 196                 return -EEXIST;
 197
 198         if (!u) {
 199                 delete = true;
 200
 201                 u = unit_new(m, sizeof(Device));
 202                 if (!u)
 203                         return -ENOMEM;
 204
 205                 r = device_add_escaped_name(u, path);
 206                 if (r < 0)
 207                         goto fail;
 208
 209                 unit_add_to_load_queue(u);
 210         } else
 211                 delete = false;
 212
 213         /* If this was created via some dependency and has not
 214          * actually been seen yet ->sysfs will not be
 215          * initialized. Hence initialize it if necessary. */
 216
 217         if (!DEVICE(u)->sysfs) {
 218                 Device *first;
 219
 220                 if (!(DEVICE(u)->sysfs = strdup(sysfs))) {
 221                         r = -ENOMEM;
 222                         goto fail;
 223                 }
 224
 225                 if (!m->devices_by_sysfs)
 226                         if (!(m->devices_by_sysfs = hashmap_new(string_hash_func, string_compare_func))) {
 227                                 r = -ENOMEM;
 228                                 goto fail;
 229                         }
 230
 231                 first = hashmap_get(m->devices_by_sysfs, sysfs);
 232                 LIST_PREPEND(Device, same_sysfs, first, DEVICE(u));
 233
 234                 if ((r = hashmap_replace(m->devices_by_sysfs, DEVICE(u)->sysfs, first)) < 0)
 235                         goto fail;
 236         }
 237
 238         if ((model = udev_device_get_property_value(dev, "ID_MODEL_FROM_DATABASE")) ||
 239             (model = udev_device_get_property_value(dev, "ID_MODEL"))) {
 240                 if ((r = unit_set_description(u, model)) < 0)
 241                         goto fail;
 242         } else
 243                 if ((r = unit_set_description(u, path)) < 0)
 244                         goto fail;
 245
 246         if (main) {
 247                 /* The additional systemd udev properties we only
 248                  * interpret for the main object */
 249                 const char *wants, *alias;
 250
 251                 if ((alias = udev_device_get_property_value(dev, "SYSTEMD_ALIAS"))) {
 252                         if (!is_path(alias))
 253                                 log_warning("SYSTEMD_ALIAS for %s is not a path, ignoring: %s", sysfs, alias);
 254                         else {
 255                                 if ((r = device_add_escaped_name(u, alias)) < 0)
 256                                         goto fail;
 257                         }
 258                 }
 259
 260                 if ((wants = udev_device_get_property_value(dev, "SYSTEMD_WANTS"))) {
 261                         char *state, *w;
 262                         size_t l;
 263
 264                         FOREACH_WORD_QUOTED(w, l, wants, state) {
 265                                 char *e;
 266
 267                                 if (!(e = strndup(w, l))) {
 268                                         r = -ENOMEM;
 269                                         goto fail;
 270                                 }
 271
 272                                 r = unit_add_dependency_by_name(u, UNIT_WANTS, e, NULL, true);
 273                                 free(e);
 274
 275                                 if (r < 0)
 276                                         goto fail;
 277                         }
 278                 }
 279         }
 280
 281         unit_add_to_dbus_queue(u);
 282         return 0;
 283
 284 fail:
 285         log_warning("Failed to load device unit: %s", strerror(-r));
 286
 287         if (delete && u)
 288                 unit_free(u);
 289
 290         return r;
 291 }
 292
 293 static int device_process_new_device(Manager *m, struct udev_device *dev, bool update_state) {
 294         const char *sysfs, *dn;
 295         struct udev_list_entry *item = NULL, *first = NULL;
 296
 297         assert(m);
 298
 299         if (!(sysfs = udev_device_get_syspath(dev)))
 300                 return -ENOMEM;
 301
 302         /* Add the main unit named after the sysfs path */
 303         device_update_unit(m, dev, sysfs, true);
 304
 305         /* Add an additional unit for the device node */
 306         if ((dn = udev_device_get_devnode(dev)))
 307                 device_update_unit(m, dev, dn, false);
 308
 309         /* Add additional units for all symlinks */
 310         first = udev_device_get_devlinks_list_entry(dev);
 311         udev_list_entry_foreach(item, first) {
 312                 const char *p;
 313                 struct stat st;
 314
 315                 /* Don't bother with the /dev/block links */
 316                 p = udev_list_entry_get_name(item);
 317
 318                 if (path_startswith(p, "/dev/block/") ||
 319                     path_startswith(p, "/dev/char/"))
 320                         continue;
 321
 322                 /* Verify that the symlink in the FS actually belongs
 323                  * to this device. This is useful to deal with
 324                  * conflicting devices, e.g. when two disks want the
 325                  * same /dev/disk/by-label/xxx link because they have
 326                  * the same label. We want to make sure that the same
 327                  * device that won the symlink wins in systemd, so we
 328                  * check the device node major/minor*/
 329                 if (stat(p, &st) >= 0)
 330                         if ((!S_ISBLK(st.st_mode) && !S_ISCHR(st.st_mode)) ||
 331                             st.st_rdev != udev_device_get_devnum(dev))
 332                                 continue;
 333
 334                 device_update_unit(m, dev, p, false);
 335         }
 336
 337         if (update_state) {
 338                 Device *d, *l;
 339
 340                 manager_dispatch_load_queue(m);
 341
 342                 l = hashmap_get(m->devices_by_sysfs, sysfs);
 343                 LIST_FOREACH(same_sysfs, d, l)
 344                         device_set_state(d, DEVICE_PLUGGED);
 345         }
 346
 347         return 0;
 348 }
 349
 350 static int device_process_path(Manager *m, const char *path, bool update_state) {
 351         int r;
 352         struct udev_device *dev;
 353
 354         assert(m);
 355         assert(path);
 356
 357         if (!(dev = udev_device_new_from_syspath(m->udev, path))) {
 358                 log_warning("Failed to get udev device object from udev for path %s.", path);
 359                 return -ENOMEM;
 360         }
 361
 362         r = device_process_new_device(m, dev, update_state);
 363         udev_device_unref(dev);
 364         return r;
 365 }
 366
 367 static int device_process_removed_device(Manager *m, struct udev_device *dev) {
 368         const char *sysfs;
 369         Device *d;
 370
 371         assert(m);
 372         assert(dev);
 373
 374         if (!(sysfs = udev_device_get_syspath(dev)))
 375                 return -ENOMEM;
 376
 377         /* Remove all units of this sysfs path */
 378         while ((d = hashmap_get(m->devices_by_sysfs, sysfs))) {
 379                 device_unset_sysfs(d);
 380                 device_set_state(d, DEVICE_DEAD);
 381         }
 382
 383         return 0;
 384 }
 385
 386 static Unit *device_following(Unit *u) {
 387         Device *d = DEVICE(u);
 388         Device *other, *first = NULL;
 389
 390         assert(d);
 391
 392         if (startswith(u->id, "sys-"))
 393                 return NULL;
 394
 395         /* Make everybody follow the unit that's named after the sysfs path */
 396         for (other = d->same_sysfs_next; other; other = other->same_sysfs_next)
 397                 if (startswith(UNIT(other)->id, "sys-"))
 398                         return UNIT(other);
 399
 400         for (other = d->same_sysfs_prev; other; other = other->same_sysfs_prev) {
 401                 if (startswith(UNIT(other)->id, "sys-"))
 402                         return UNIT(other);
 403
 404                 first = other;
 405         }
 406
 407         return UNIT(first);
 408 }
 409
 410 static int device_following_set(Unit *u, Set **_s) {
 411         Device *d = DEVICE(u);
 412         Device *other;
 413         Set *s;
 414         int r;
 415
 416         assert(d);
 417         assert(_s);
 418
 419         if (!d->same_sysfs_prev && !d->same_sysfs_next) {
 420                 *_s = NULL;
 421                 return 0;
 422         }
 423
 424         if (!(s = set_new(NULL, NULL)))
 425                 return -ENOMEM;
 426
 427         for (other = d->same_sysfs_next; other; other = other->same_sysfs_next)
 428                 if ((r = set_put(s, other)) < 0)
 429                         goto fail;
 430
 431         for (other = d->same_sysfs_prev; other; other = other->same_sysfs_prev)
 432                 if ((r = set_put(s, other)) < 0)
 433                         goto fail;
 434
 435         *_s = s;
 436         return 1;
 437
 438 fail:
 439         set_free(s);
 440         return r;
 441 }
 442
 443 static void device_shutdown(Manager *m) {
 444         assert(m);
 445
 446         if (m->udev_monitor) {
 447                 udev_monitor_unref(m->udev_monitor);
 448                 m->udev_monitor = NULL;
 449         }
 450
 451         if (m->udev) {
 452                 udev_unref(m->udev);
 453                 m->udev = NULL;
 454         }
 455
 456         hashmap_free(m->devices_by_sysfs);
 457         m->devices_by_sysfs = NULL;
 458 }
 459
 460 static int device_enumerate(Manager *m) {
 461         struct epoll_event ev;
 462         int r;
 463         struct udev_enumerate *e = NULL;
 464         struct udev_list_entry *item = NULL, *first = NULL;
 465
 466         assert(m);
 467
 468         if (!m->udev) {
 469                 if (!(m->udev = udev_new()))
 470                         return -ENOMEM;
 471
 472                 if (!(m->udev_monitor = udev_monitor_new_from_netlink(m->udev, "udev"))) {
 473                         r = -ENOMEM;
 474                         goto fail;
 475                 }
 476
 477                 /* This will fail if we are unprivileged, but that
 478                  * should not matter much, as user instances won't run
 479                  * during boot. */
 480                 udev_monitor_set_receive_buffer_size(m->udev_monitor, 128*1024*1024);
 481
 482                 if (udev_monitor_filter_add_match_tag(m->udev_monitor, "systemd") < 0) {
 483                         r = -ENOMEM;
 484                         goto fail;
 485                 }
 486
 487                 if (udev_monitor_enable_receiving(m->udev_monitor) < 0) {
 488                         r = -EIO;
 489                         goto fail;
 490                 }
 491
 492                 m->udev_watch.type = WATCH_UDEV;
 493                 m->udev_watch.fd = udev_monitor_get_fd(m->udev_monitor);
 494
 495                 zero(ev);
 496                 ev.events = EPOLLIN;
 497                 ev.data.ptr = &m->udev_watch;
 498
 499                 if (epoll_ctl(m->epoll_fd, EPOLL_CTL_ADD, m->udev_watch.fd, &ev) < 0)
 500                         return -errno;
 501         }
 502
 503         if (!(e = udev_enumerate_new(m->udev))) {
 504                 r = -ENOMEM;
 505                 goto fail;
 506         }
 507         if (udev_enumerate_add_match_tag(e, "systemd") < 0) {
 508                 r = -EIO;
 509                 goto fail;
 510         }
 511
 512         if (udev_enumerate_scan_devices(e) < 0) {
 513                 r = -EIO;
 514                 goto fail;
 515         }
 516
 517         first = udev_enumerate_get_list_entry(e);
 518         udev_list_entry_foreach(item, first)
 519                 device_process_path(m, udev_list_entry_get_name(item), false);
 520
 521         udev_enumerate_unref(e);
 522         return 0;
 523
 524 fail:
 525         if (e)
 526                 udev_enumerate_unref(e);
 527
 528         device_shutdown(m);
 529         return r;
 530 }
 531
 532 void device_fd_event(Manager *m, int events) {
 533         struct udev_device *dev;
 534         int r;
 535         const char *action, *ready;
 536
 537         assert(m);
 538
 539         if (events != EPOLLIN) {
 540                 static RATELIMIT_DEFINE(limit, 10*USEC_PER_SEC, 5);
 541
 542                 if (!ratelimit_test(&limit))
 543                         log_error("Failed to get udev event: %m");
 544                 if (!(events & EPOLLIN))
 545                         return;
 546         }
 547
 548         if (!(dev = udev_monitor_receive_device(m->udev_monitor))) {
 549                 /*
 550                  * libudev might filter-out devices which pass the bloom filter,
 551                  * so getting NULL here is not necessarily an error
 552                  */
 553                 return;
 554         }
 555
 556         if (!(action = udev_device_get_action(dev))) {
 557                 log_error("Failed to get udev action string.");
 558                 goto fail;
 559         }
 560
 561         ready = udev_device_get_property_value(dev, "SYSTEMD_READY");
 562
 563         if (streq(action, "remove") || (ready && parse_boolean(ready) == 0)) {
 564                 if ((r = device_process_removed_device(m, dev)) < 0) {
 565                         log_error("Failed to process udev device event: %s", strerror(-r));
 566                         goto fail;
 567                 }
 568         } else {
 569                 if ((r = device_process_new_device(m, dev, true)) < 0) {
 570                         log_error("Failed to process udev device event: %s", strerror(-r));
 571                         goto fail;
 572                 }
 573         }
 574
 575 fail:
 576         udev_device_unref(dev);
 577 }
 578
 579 static const char* const device_state_table[_DEVICE_STATE_MAX] = {
 580         [DEVICE_DEAD] = "dead",
 581         [DEVICE_PLUGGED] = "plugged"
 582 };
 583
 584 DEFINE_STRING_TABLE_LOOKUP(device_state, DeviceState);
 585
 586 const UnitVTable device_vtable = {
 587         .suffix = ".device",
 588         .object_size = sizeof(Device),
 589         .sections =
 590                 "Unit\0"
 591                 "Device\0"
 592                 "Install\0",
 593
 594         .no_instances = true,
 595
 596         .init = device_init,
 597
 598         .load = unit_load_fragment_and_dropin_optional,
 599         .done = device_done,
 600         .coldplug = device_coldplug,
 601
 602         .dump = device_dump,
 603
 604         .active_state = device_active_state,
 605         .sub_state_to_string = device_sub_state_to_string,
 606
 607         .bus_interface = "org.freedesktop.systemd1.Device",
 608         .bus_message_handler = bus_device_message_handler,
 609         .bus_invalidating_properties =  bus_device_invalidating_properties,
 610
 611         .following = device_following,
 612         .following_set = device_following_set,
 613
 614         .enumerate = device_enumerate,
 615         .shutdown = device_shutdown
 616 };