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                 /* Remove this unit from the chain of devices which share the
  45                  * same sysfs path. */
  46                 first = hashmap_get(d->meta.manager->devices_by_sysfs, d->sysfs);
  47                 LIST_REMOVE(Device, same_sysfs, first, d);
  48
  49                 if (first)
  50                         hashmap_remove_and_replace(d->meta.manager->devices_by_sysfs, d->sysfs, first->sysfs, first);
  51                 else
  52                         hashmap_remove(d->meta.manager->devices_by_sysfs, d->sysfs);
  53
  54                 free(d->sysfs);
  55                 d->sysfs = NULL;
  56         }
  57
  58         d->meta.following = NULL;
  59 }
  60
  61 static void device_init(Unit *u) {
  62         Device *d = DEVICE(u);
  63
  64         assert(d);
  65         assert(d->meta.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          * indefinetely for plugged in devices, something which cannot
  70          * happen for the other units since their operations time out
  71          * anyway. */
  72         d->meta.job_timeout = DEFAULT_TIMEOUT_USEC;
  73 }
  74
  75 static void device_done(Unit *u) {
  76         Device *d = DEVICE(u);
  77
  78         assert(d);
  79
  80         device_unset_sysfs(d);
  81 }
  82
  83 static void device_set_state(Device *d, DeviceState state) {
  84         DeviceState old_state;
  85         assert(d);
  86
  87         old_state = d->state;
  88         d->state = state;
  89
  90         if (state != old_state)
  91                 log_debug("%s changed %s -> %s",
  92                           d->meta.id,
  93                           device_state_to_string(old_state),
  94                           device_state_to_string(state));
  95
  96         unit_notify(UNIT(d), state_translation_table[old_state], state_translation_table[state]);
  97 }
  98
  99 static int device_coldplug(Unit *u) {
 100         Device *d = DEVICE(u);
 101
 102         assert(d);
 103         assert(d->state == DEVICE_DEAD);
 104
 105         if (d->sysfs)
 106                 device_set_state(d, DEVICE_PLUGGED);
 107
 108         return 0;
 109 }
 110
 111 static void device_dump(Unit *u, FILE *f, const char *prefix) {
 112         Device *d = DEVICE(u);
 113
 114         assert(d);
 115
 116         fprintf(f,
 117                 "%sDevice State: %s\n"
 118                 "%sSysfs Path: %s\n",
 119                 prefix, device_state_to_string(d->state),
 120                 prefix, strna(d->sysfs));
 121 }
 122
 123 static UnitActiveState device_active_state(Unit *u) {
 124         assert(u);
 125
 126         return state_translation_table[DEVICE(u)->state];
 127 }
 128
 129 static const char *device_sub_state_to_string(Unit *u) {
 130         assert(u);
 131
 132         return device_state_to_string(DEVICE(u)->state);
 133 }
 134
 135 static int device_add_escaped_name(Unit *u, const char *dn) {
 136         char *e;
 137         int r;
 138
 139         assert(u);
 140         assert(dn);
 141         assert(dn[0] == '/');
 142
 143         if (!(e = unit_name_from_path(dn, ".device")))
 144                 return -ENOMEM;
 145
 146         r = unit_add_name(u, e);
 147         free(e);
 148
 149         if (r < 0 && r != -EEXIST)
 150                 return r;
 151
 152         return 0;
 153 }
 154
 155 static int device_find_escape_name(Manager *m, const char *dn, Unit **_u) {
 156         char *e;
 157         Unit *u;
 158
 159         assert(m);
 160         assert(dn);
 161         assert(dn[0] == '/');
 162         assert(_u);
 163
 164         if (!(e = unit_name_from_path(dn, ".device")))
 165                 return -ENOMEM;
 166
 167         u = manager_get_unit(m, e);
 168         free(e);
 169
 170         if (u) {
 171                 *_u = u;
 172                 return 1;
 173         }
 174
 175         return 0;
 176 }
 177
 178 static int device_update_unit(Manager *m, struct udev_device *dev, const char *path, bool main) {
 179         const char *sysfs, *model;
 180         Unit *u = NULL;
 181         int r;
 182         bool delete;
 183
 184         assert(m);
 185
 186         if (!(sysfs = udev_device_get_syspath(dev)))
 187                 return -ENOMEM;
 188
 189         if ((r = device_find_escape_name(m, path, &u)) < 0)
 190                 return r;
 191
 192         /* If this is a different unit, then let's not merge things */
 193         if (u && DEVICE(u)->sysfs && !path_equal(DEVICE(u)->sysfs, sysfs)) {
 194                 log_error("Hmm, something's broken. Asked to create two devices with same name but different sysfs paths.");
 195                 return -EEXIST;
 196         }
 197
 198         if (!u) {
 199                 Device *first;
 200                 delete = true;
 201
 202                 if (!(u = unit_new(m)))
 203                         return -ENOMEM;
 204
 205                 if ((r = device_add_escaped_name(u, path)) < 0)
 206                         goto fail;
 207
 208                 if (!(DEVICE(u)->sysfs = strdup(sysfs))) {
 209                         r = -ENOMEM;
 210                         goto fail;
 211                 }
 212
 213                 unit_add_to_load_queue(u);
 214
 215                 if (!m->devices_by_sysfs)
 216                         if (!(m->devices_by_sysfs = hashmap_new(string_hash_func, string_compare_func))) {
 217                                 r = -ENOMEM;
 218                                 goto fail;
 219                         }
 220
 221                 first = hashmap_get(m->devices_by_sysfs, sysfs);
 222                 LIST_PREPEND(Device, same_sysfs, first, DEVICE(u));
 223
 224                 if ((r = hashmap_replace(m->devices_by_sysfs, DEVICE(u)->sysfs, first)) < 0)
 225                         goto fail;
 226
 227         } else
 228                 delete = false;
 229
 230         if ((model = udev_device_get_property_value(dev, "ID_MODEL_FROM_DATABASE")) ||
 231             (model = udev_device_get_property_value(dev, "ID_MODEL"))) {
 232                 if ((r = unit_set_description(u, model)) < 0)
 233                         goto fail;
 234         } else
 235                 if ((r = unit_set_description(u, path)) < 0)
 236                         goto fail;
 237
 238         if (main) {
 239                 /* The additional systemd udev properties we only
 240                  * interpret for the main object */
 241                 const char *wants, *alias;
 242
 243                 if ((alias = udev_device_get_property_value(dev, "SYSTEMD_ALIAS"))) {
 244                         if (!is_path(alias))
 245                                 log_warning("SYSTEMD_ALIAS for %s is not a path, ignoring: %s", sysfs, alias);
 246                         else {
 247                                 if ((r = device_add_escaped_name(u, alias)) < 0)
 248                                         goto fail;
 249                         }
 250                 }
 251
 252                 if ((wants = udev_device_get_property_value(dev, "SYSTEMD_WANTS"))) {
 253                         char *state, *w;
 254                         size_t l;
 255
 256                         FOREACH_WORD_QUOTED(w, l, wants, state) {
 257                                 char *e;
 258
 259                                 if (!(e = strndup(w, l))) {
 260                                         r = -ENOMEM;
 261                                         goto fail;
 262                                 }
 263
 264                                 r = unit_add_dependency_by_name(u, UNIT_WANTS, e, NULL, true);
 265                                 free(e);
 266
 267                                 if (r < 0)
 268                                         goto fail;
 269                         }
 270                 }
 271
 272                 u->meta.following = NULL;
 273         } else
 274                 device_find_escape_name(m, sysfs, &u->meta.following);
 275
 276         unit_add_to_dbus_queue(u);
 277         return 0;
 278
 279 fail:
 280         log_warning("Failed to load device unit: %s", strerror(-r));
 281
 282         if (delete && u)
 283                 unit_free(u);
 284
 285         return r;
 286 }
 287
 288 static int device_process_new_device(Manager *m, struct udev_device *dev, bool update_state) {
 289         const char *sysfs, *dn;
 290         struct udev_list_entry *item = NULL, *first = NULL;
 291
 292         assert(m);
 293
 294         if (!(sysfs = udev_device_get_syspath(dev)))
 295                 return -ENOMEM;
 296
 297         /* Add the main unit named after the sysfs path */
 298         device_update_unit(m, dev, sysfs, true);
 299
 300         /* Add an additional unit for the device node */
 301         if ((dn = udev_device_get_devnode(dev)))
 302                 device_update_unit(m, dev, dn, false);
 303
 304         /* Add additional units for all symlinks */
 305         first = udev_device_get_devlinks_list_entry(dev);
 306         udev_list_entry_foreach(item, first) {
 307                 const char *p;
 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                 device_update_unit(m, dev, p, false);
 317         }
 318
 319         if (update_state) {
 320                 Device *d, *l;
 321
 322                 manager_dispatch_load_queue(m);
 323
 324                 l = hashmap_get(m->devices_by_sysfs, sysfs);
 325                 LIST_FOREACH(same_sysfs, d, l)
 326                         device_set_state(d, DEVICE_PLUGGED);
 327         }
 328
 329         return 0;
 330 }
 331
 332 static int device_process_path(Manager *m, const char *path, bool update_state) {
 333         int r;
 334         struct udev_device *dev;
 335
 336         assert(m);
 337         assert(path);
 338
 339         if (!(dev = udev_device_new_from_syspath(m->udev, path))) {
 340                 log_warning("Failed to get udev device object from udev for path %s.", path);
 341                 return -ENOMEM;
 342         }
 343
 344         r = device_process_new_device(m, dev, update_state);
 345         udev_device_unref(dev);
 346         return r;
 347 }
 348
 349 static int device_process_removed_device(Manager *m, struct udev_device *dev) {
 350         const char *sysfs;
 351         Device *d;
 352
 353         assert(m);
 354         assert(dev);
 355
 356         if (!(sysfs = udev_device_get_syspath(dev)))
 357                 return -ENOMEM;
 358
 359         /* Remove all units of this sysfs path */
 360         while ((d = hashmap_get(m->devices_by_sysfs, sysfs))) {
 361                 device_unset_sysfs(d);
 362                 device_set_state(d, DEVICE_DEAD);
 363         }
 364
 365         return 0;
 366 }
 367
 368 static void device_shutdown(Manager *m) {
 369         assert(m);
 370
 371         if (m->udev_monitor) {
 372                 udev_monitor_unref(m->udev_monitor);
 373                 m->udev_monitor = NULL;
 374         }
 375
 376         if (m->udev) {
 377                 udev_unref(m->udev);
 378                 m->udev = NULL;
 379         }
 380
 381         hashmap_free(m->devices_by_sysfs);
 382         m->devices_by_sysfs = NULL;
 383 }
 384
 385 static int device_enumerate(Manager *m) {
 386         struct epoll_event ev;
 387         int r;
 388         struct udev_enumerate *e = NULL;
 389         struct udev_list_entry *item = NULL, *first = NULL;
 390
 391         assert(m);
 392
 393         if (!m->udev) {
 394                 if (!(m->udev = udev_new()))
 395                         return -ENOMEM;
 396
 397                 if (!(m->udev_monitor = udev_monitor_new_from_netlink(m->udev, "udev"))) {
 398                         r = -ENOMEM;
 399                         goto fail;
 400                 }
 401
 402                 if (udev_monitor_filter_add_match_tag(m->udev_monitor, "systemd") < 0) {
 403                         r = -ENOMEM;
 404                         goto fail;
 405                 }
 406
 407                 if (udev_monitor_enable_receiving(m->udev_monitor) < 0) {
 408                         r = -EIO;
 409                         goto fail;
 410                 }
 411
 412                 m->udev_watch.type = WATCH_UDEV;
 413                 m->udev_watch.fd = udev_monitor_get_fd(m->udev_monitor);
 414
 415                 zero(ev);
 416                 ev.events = EPOLLIN;
 417                 ev.data.ptr = &m->udev_watch;
 418
 419                 if (epoll_ctl(m->epoll_fd, EPOLL_CTL_ADD, m->udev_watch.fd, &ev) < 0)
 420                         return -errno;
 421         }
 422
 423         if (!(e = udev_enumerate_new(m->udev))) {
 424                 r = -ENOMEM;
 425                 goto fail;
 426         }
 427         if (udev_enumerate_add_match_tag(e, "systemd") < 0) {
 428                 r = -EIO;
 429                 goto fail;
 430         }
 431
 432         if (udev_enumerate_scan_devices(e) < 0) {
 433                 r = -EIO;
 434                 goto fail;
 435         }
 436
 437         first = udev_enumerate_get_list_entry(e);
 438         udev_list_entry_foreach(item, first)
 439                 device_process_path(m, udev_list_entry_get_name(item), false);
 440
 441         udev_enumerate_unref(e);
 442         return 0;
 443
 444 fail:
 445         if (e)
 446                 udev_enumerate_unref(e);
 447
 448         device_shutdown(m);
 449         return r;
 450 }
 451
 452 void device_fd_event(Manager *m, int events) {
 453         struct udev_device *dev;
 454         int r;
 455         const char *action;
 456
 457         assert(m);
 458         assert(events == EPOLLIN);
 459
 460         if (!(dev = udev_monitor_receive_device(m->udev_monitor))) {
 461                 log_error("Failed to receive device.");
 462                 return;
 463         }
 464
 465         if (!(action = udev_device_get_action(dev))) {
 466                 log_error("Failed to get udev action string.");
 467                 goto fail;
 468         }
 469
 470         if (streq(action, "remove")) {
 471                 if ((r = device_process_removed_device(m, dev)) < 0) {
 472                         log_error("Failed to process udev device event: %s", strerror(-r));
 473                         goto fail;
 474                 }
 475         } else {
 476                 if ((r = device_process_new_device(m, dev, true)) < 0) {
 477                         log_error("Failed to process udev device event: %s", strerror(-r));
 478                         goto fail;
 479                 }
 480         }
 481
 482 fail:
 483         udev_device_unref(dev);
 484 }
 485
 486 static const char* const device_state_table[_DEVICE_STATE_MAX] = {
 487         [DEVICE_DEAD] = "dead",
 488         [DEVICE_PLUGGED] = "plugged"
 489 };
 490
 491 DEFINE_STRING_TABLE_LOOKUP(device_state, DeviceState);
 492
 493 const UnitVTable device_vtable = {
 494         .suffix = ".device",
 495
 496         .no_requires = true,
 497         .no_instances = true,
 498         .no_snapshots = true,
 499         .no_isolate = true,
 500         .no_alias = true,
 501
 502         .init = device_init,
 503
 504         .load = unit_load_fragment_and_dropin_optional,
 505         .done = device_done,
 506         .coldplug = device_coldplug,
 507
 508         .dump = device_dump,
 509
 510         .active_state = device_active_state,
 511         .sub_state_to_string = device_sub_state_to_string,
 512
 513         .bus_message_handler = bus_device_message_handler,
 514
 515         .enumerate = device_enumerate,
 516         .shutdown = device_shutdown
 517 };