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_init(Unit *u) {
  39         Device *d = DEVICE(u);
  40
  41         assert(d);
  42         assert(d->meta.load_state == UNIT_STUB);
  43
  44         d->meta.job_timeout = DEFAULT_TIMEOUT_USEC;
  45 }
  46
  47 static void device_done(Unit *u) {
  48         Device *d = DEVICE(u);
  49
  50         assert(d);
  51
  52         free(d->sysfs);
  53         d->sysfs = NULL;
  54 }
  55
  56 static void device_set_state(Device *d, DeviceState state) {
  57         DeviceState old_state;
  58         assert(d);
  59
  60         old_state = d->state;
  61         d->state = state;
  62
  63         if (state != old_state)
  64                 log_debug("%s changed %s -> %s",
  65                           d->meta.id,
  66                           device_state_to_string(old_state),
  67                           device_state_to_string(state));
  68
  69         unit_notify(UNIT(d), state_translation_table[old_state], state_translation_table[state]);
  70 }
  71
  72 static int device_coldplug(Unit *u) {
  73         Device *d = DEVICE(u);
  74
  75         assert(d);
  76         assert(d->state == DEVICE_DEAD);
  77
  78         if (d->sysfs)
  79                 device_set_state(d, DEVICE_PLUGGED);
  80
  81         return 0;
  82 }
  83
  84 static void device_dump(Unit *u, FILE *f, const char *prefix) {
  85         Device *d = DEVICE(u);
  86
  87         assert(d);
  88
  89         fprintf(f,
  90                 "%sDevice State: %s\n"
  91                 "%sSysfs Path: %s\n",
  92                 prefix, device_state_to_string(d->state),
  93                 prefix, strna(d->sysfs));
  94 }
  95
  96 static UnitActiveState device_active_state(Unit *u) {
  97         assert(u);
  98
  99         return state_translation_table[DEVICE(u)->state];
 100 }
 101
 102 static const char *device_sub_state_to_string(Unit *u) {
 103         assert(u);
 104
 105         return device_state_to_string(DEVICE(u)->state);
 106 }
 107
 108 static int device_add_escaped_name(Unit *u, const char *dn, bool make_id) {
 109         char *e;
 110         int r;
 111
 112         assert(u);
 113         assert(dn);
 114         assert(dn[0] == '/');
 115
 116         if (!(e = unit_name_from_path(dn, ".device")))
 117                 return -ENOMEM;
 118
 119         r = unit_add_name(u, e);
 120
 121         if (r >= 0 && make_id)
 122                 unit_choose_id(u, e);
 123
 124         free(e);
 125
 126         if (r < 0 && r != -EEXIST)
 127                 return r;
 128
 129         return 0;
 130 }
 131
 132 static int device_find_escape_name(Manager *m, const char *dn, Unit **_u) {
 133         char *e;
 134         Unit *u;
 135
 136         assert(m);
 137         assert(dn);
 138         assert(dn[0] == '/');
 139         assert(_u);
 140
 141         if (!(e = unit_name_from_path(dn, ".device")))
 142                 return -ENOMEM;
 143
 144         u = manager_get_unit(m, e);
 145         free(e);
 146
 147         if (u) {
 148                 *_u = u;
 149                 return 1;
 150         }
 151
 152         return 0;
 153 }
 154
 155 static int device_process_new_device(Manager *m, struct udev_device *dev, bool update_state) {
 156         const char *dn, *wants, *sysfs, *model, *alias;
 157         Unit *u = NULL;
 158         int r;
 159         char *w, *state;
 160         size_t l;
 161         bool delete;
 162         struct udev_list_entry *item = NULL, *first = NULL;
 163
 164         assert(m);
 165
 166         if (!(sysfs = udev_device_get_syspath(dev)))
 167                 return -ENOMEM;
 168
 169         /* Check whether this entry is even relevant for us. */
 170         dn = udev_device_get_devnode(dev);
 171         wants = udev_device_get_property_value(dev, "SYSTEMD_WANTS");
 172         alias = udev_device_get_property_value(dev, "SYSTEMD_ALIAS");
 173
 174         /* We allow exactly one alias to be configured a this time and
 175          * it must be a path */
 176
 177         if (alias && !is_path(alias)) {
 178                 log_warning("SYSTEMD_ALIAS for %s is not a path, ignoring: %s", sysfs, alias);
 179                 alias = NULL;
 180         }
 181
 182         if ((r = device_find_escape_name(m, sysfs, &u)) < 0)
 183                 return r;
 184
 185         if (r == 0 && dn)
 186                 if ((r = device_find_escape_name(m, dn, &u)) < 0)
 187                         return r;
 188
 189         if (r == 0) {
 190                 first = udev_device_get_devlinks_list_entry(dev);
 191                 udev_list_entry_foreach(item, first) {
 192                         if ((r = device_find_escape_name(m, udev_list_entry_get_name(item), &u)) < 0)
 193                                 return r;
 194
 195                         if (r > 0)
 196                                 break;
 197                 }
 198         }
 199
 200         if (r == 0 && alias)
 201                 if ((r = device_find_escape_name(m, alias, &u)) < 0)
 202                         return r;
 203
 204         /* FIXME: this needs proper merging */
 205
 206         assert((r > 0) == !!u);
 207
 208         /* If this is a different unit, then let's not merge things */
 209         if (u && DEVICE(u)->sysfs && !path_equal(DEVICE(u)->sysfs, sysfs))
 210                 u = NULL;
 211
 212         if (!u) {
 213                 delete = true;
 214
 215                 if (!(u = unit_new(m)))
 216                         return -ENOMEM;
 217
 218                 if ((r = device_add_escaped_name(u, sysfs, true)) < 0)
 219                         goto fail;
 220
 221                 unit_add_to_load_queue(u);
 222         } else
 223                 delete = false;
 224
 225         if (!(DEVICE(u)->sysfs))
 226                 if (!(DEVICE(u)->sysfs = strdup(sysfs))) {
 227                         r = -ENOMEM;
 228                         goto fail;
 229                 }
 230
 231         if (alias)
 232                 if ((r = device_add_escaped_name(u, alias, true)) < 0)
 233                         goto fail;
 234
 235         if (dn)
 236                 if ((r = device_add_escaped_name(u, dn, true)) < 0)
 237                         goto fail;
 238
 239         first = udev_device_get_devlinks_list_entry(dev);
 240         udev_list_entry_foreach(item, first)
 241                 if ((r = device_add_escaped_name(u, udev_list_entry_get_name(item), false)) < 0)
 242                         goto fail;
 243
 244         if ((model = udev_device_get_property_value(dev, "ID_MODEL_FROM_DATABASE")) ||
 245             (model = udev_device_get_property_value(dev, "ID_MODEL"))) {
 246                 if ((r = unit_set_description(u, model)) < 0)
 247                         goto fail;
 248         } else if (dn) {
 249                 if ((r = unit_set_description(u, dn)) < 0)
 250                         goto fail;
 251         } else
 252                 if ((r = unit_set_description(u, sysfs)) < 0)
 253                         goto fail;
 254
 255         if (wants) {
 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         if (update_state) {
 273                 manager_dispatch_load_queue(u->meta.manager);
 274                 device_set_state(DEVICE(u), DEVICE_PLUGGED);
 275         }
 276
 277         unit_add_to_dbus_queue(u);
 278
 279         return 0;
 280
 281 fail:
 282
 283         log_warning("Failed to load device unit: %s", strerror(-r));
 284
 285         if (delete && u)
 286                 unit_free(u);
 287
 288         return r;
 289 }
 290
 291 static int device_process_path(Manager *m, const char *path, bool update_state) {
 292         int r;
 293         struct udev_device *dev;
 294
 295         assert(m);
 296         assert(path);
 297
 298         if (!(dev = udev_device_new_from_syspath(m->udev, path))) {
 299                 log_warning("Failed to get udev device object from udev for path %s.", path);
 300                 return -ENOMEM;
 301         }
 302
 303         r = device_process_new_device(m, dev, update_state);
 304         udev_device_unref(dev);
 305         return r;
 306 }
 307
 308 static int device_process_removed_device(Manager *m, struct udev_device *dev) {
 309         const char *sysfs;
 310         char *e;
 311         Unit *u;
 312         Device *d;
 313
 314         assert(m);
 315         assert(dev);
 316
 317         if (!(sysfs = udev_device_get_syspath(dev)))
 318                 return -ENOMEM;
 319
 320         assert(sysfs[0] == '/');
 321         if (!(e = unit_name_from_path(sysfs, ".device")))
 322                 return -ENOMEM;
 323
 324         u = manager_get_unit(m, e);
 325         free(e);
 326
 327         if (!u)
 328                 return 0;
 329
 330         d = DEVICE(u);
 331         free(d->sysfs);
 332         d->sysfs = NULL;
 333
 334         device_set_state(d, DEVICE_DEAD);
 335         return 0;
 336 }
 337
 338 static void device_shutdown(Manager *m) {
 339         assert(m);
 340
 341         if (m->udev_monitor) {
 342                 udev_monitor_unref(m->udev_monitor);
 343                 m->udev_monitor = NULL;
 344         }
 345
 346         if (m->udev) {
 347                 udev_unref(m->udev);
 348                 m->udev = NULL;
 349         }
 350 }
 351
 352 static int device_enumerate(Manager *m) {
 353         struct epoll_event ev;
 354         int r;
 355         struct udev_enumerate *e = NULL;
 356         struct udev_list_entry *item = NULL, *first = NULL;
 357
 358         assert(m);
 359
 360         if (!m->udev) {
 361                 if (!(m->udev = udev_new()))
 362                         return -ENOMEM;
 363
 364                 if (!(m->udev_monitor = udev_monitor_new_from_netlink(m->udev, "udev"))) {
 365                         r = -ENOMEM;
 366                         goto fail;
 367                 }
 368
 369                 if (udev_monitor_filter_add_match_tag(m->udev_monitor, "systemd") < 0) {
 370                         r = -ENOMEM;
 371                         goto fail;
 372                 }
 373
 374                 if (udev_monitor_enable_receiving(m->udev_monitor) < 0) {
 375                         r = -EIO;
 376                         goto fail;
 377                 }
 378
 379                 m->udev_watch.type = WATCH_UDEV;
 380                 m->udev_watch.fd = udev_monitor_get_fd(m->udev_monitor);
 381
 382                 zero(ev);
 383                 ev.events = EPOLLIN;
 384                 ev.data.ptr = &m->udev_watch;
 385
 386                 if (epoll_ctl(m->epoll_fd, EPOLL_CTL_ADD, m->udev_watch.fd, &ev) < 0)
 387                         return -errno;
 388         }
 389
 390         if (!(e = udev_enumerate_new(m->udev))) {
 391                 r = -ENOMEM;
 392                 goto fail;
 393         }
 394         if (udev_enumerate_add_match_tag(e, "systemd") < 0) {
 395                 r = -EIO;
 396                 goto fail;
 397         }
 398
 399         if (udev_enumerate_scan_devices(e) < 0) {
 400                 r = -EIO;
 401                 goto fail;
 402         }
 403
 404         first = udev_enumerate_get_list_entry(e);
 405         udev_list_entry_foreach(item, first)
 406                 device_process_path(m, udev_list_entry_get_name(item), false);
 407
 408         udev_enumerate_unref(e);
 409         return 0;
 410
 411 fail:
 412         if (e)
 413                 udev_enumerate_unref(e);
 414
 415         device_shutdown(m);
 416         return r;
 417 }
 418
 419 void device_fd_event(Manager *m, int events) {
 420         struct udev_device *dev;
 421         int r;
 422         const char *action;
 423
 424         assert(m);
 425         assert(events == EPOLLIN);
 426
 427         if (!(dev = udev_monitor_receive_device(m->udev_monitor))) {
 428                 log_error("Failed to receive device.");
 429                 return;
 430         }
 431
 432         if (!(action = udev_device_get_action(dev))) {
 433                 log_error("Failed to get udev action string.");
 434                 goto fail;
 435         }
 436
 437         if (streq(action, "remove")) {
 438                 if ((r = device_process_removed_device(m, dev)) < 0) {
 439                         log_error("Failed to process udev device event: %s", strerror(-r));
 440                         goto fail;
 441                 }
 442         } else {
 443                 if ((r = device_process_new_device(m, dev, true)) < 0) {
 444                         log_error("Failed to process udev device event: %s", strerror(-r));
 445                         goto fail;
 446                 }
 447         }
 448
 449 fail:
 450         udev_device_unref(dev);
 451 }
 452
 453 static const char* const device_state_table[_DEVICE_STATE_MAX] = {
 454         [DEVICE_DEAD] = "dead",
 455         [DEVICE_PLUGGED] = "plugged"
 456 };
 457
 458 DEFINE_STRING_TABLE_LOOKUP(device_state, DeviceState);
 459
 460 const UnitVTable device_vtable = {
 461         .suffix = ".device",
 462
 463         .no_requires = true,
 464         .no_instances = true,
 465         .no_snapshots = true,
 466         .no_isolate = true,
 467
 468         .init = device_init,
 469
 470         .load = unit_load_fragment_and_dropin_optional,
 471         .done = device_done,
 472         .coldplug = device_coldplug,
 473
 474         .dump = device_dump,
 475
 476         .active_state = device_active_state,
 477         .sub_state_to_string = device_sub_state_to_string,
 478
 479         .bus_message_handler = bus_device_message_handler,
 480
 481         .enumerate = device_enumerate,
 482         .shutdown = device_shutdown
 483 };