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_AVAILABLE] = UNIT_ACTIVE
  36 };
  37
  38 static void device_done(Unit *u) {
  39         Device *d = DEVICE(u);
  40
  41         assert(d);
  42
  43         free(d->sysfs);
  44         d->sysfs = NULL;
  45 }
  46
  47 static void device_set_state(Device *d, DeviceState state) {
  48         DeviceState old_state;
  49         assert(d);
  50
  51         old_state = d->state;
  52         d->state = state;
  53
  54         if (state != old_state)
  55                 log_debug("%s changed %s -> %s",
  56                           d->meta.id,
  57                           device_state_to_string(old_state),
  58                           device_state_to_string(state));
  59
  60         unit_notify(UNIT(d), state_translation_table[old_state], state_translation_table[state]);
  61 }
  62
  63 static int device_coldplug(Unit *u) {
  64         Device *d = DEVICE(u);
  65
  66         assert(d);
  67         assert(d->state == DEVICE_DEAD);
  68
  69         if (d->sysfs)
  70                 device_set_state(d, DEVICE_AVAILABLE);
  71
  72         return 0;
  73 }
  74
  75 static void device_dump(Unit *u, FILE *f, const char *prefix) {
  76         Device *d = DEVICE(u);
  77
  78         assert(d);
  79
  80         fprintf(f,
  81                 "%sDevice State: %s\n"
  82                 "%sSysfs Path: %s\n",
  83                 prefix, device_state_to_string(d->state),
  84                 prefix, strna(d->sysfs));
  85 }
  86
  87 static UnitActiveState device_active_state(Unit *u) {
  88         assert(u);
  89
  90         return state_translation_table[DEVICE(u)->state];
  91 }
  92
  93 static const char *device_sub_state_to_string(Unit *u) {
  94         assert(u);
  95
  96         return device_state_to_string(DEVICE(u)->state);
  97 }
  98
  99 static int device_add_escaped_name(Unit *u, const char *dn, bool make_id) {
 100         char *e;
 101         int r;
 102
 103         assert(u);
 104         assert(dn);
 105         assert(dn[0] == '/');
 106
 107         if (!(e = unit_name_from_path(dn, ".device")))
 108                 return -ENOMEM;
 109
 110         r = unit_add_name(u, e);
 111
 112         if (r >= 0 && make_id)
 113                 unit_choose_id(u, e);
 114
 115         free(e);
 116
 117         if (r < 0 && r != -EEXIST)
 118                 return r;
 119
 120         return 0;
 121 }
 122
 123 static int device_find_escape_name(Manager *m, const char *dn, Unit **_u) {
 124         char *e;
 125         Unit *u;
 126
 127         assert(m);
 128         assert(dn);
 129         assert(dn[0] == '/');
 130         assert(_u);
 131
 132         if (!(e = unit_name_from_path(dn, ".device")))
 133                 return -ENOMEM;
 134
 135         u = manager_get_unit(m, e);
 136         free(e);
 137
 138         if (u) {
 139                 *_u = u;
 140                 return 1;
 141         }
 142
 143         return 0;
 144 }
 145
 146 static int device_process_new_device(Manager *m, struct udev_device *dev, bool update_state) {
 147         const char *dn, *wants, *sysfs, *model, *alias;
 148         Unit *u = NULL;
 149         int r;
 150         char *w, *state;
 151         size_t l;
 152         bool delete;
 153         struct udev_list_entry *item = NULL, *first = NULL;
 154
 155         assert(m);
 156
 157         if (!(sysfs = udev_device_get_syspath(dev)))
 158                 return -ENOMEM;
 159
 160         /* Check whether this entry is even relevant for us. */
 161         dn = udev_device_get_devnode(dev);
 162         wants = udev_device_get_property_value(dev, "SYSTEMD_WANTS");
 163         alias = udev_device_get_property_value(dev, "SYSTEMD_ALIAS");
 164
 165         /* We allow exactly one alias to be configured a this time and
 166          * it must be a path */
 167
 168         if (alias && !is_path(alias)) {
 169                 log_warning("SYSTEMD_ALIAS for %s is not a path, ignoring: %s", sysfs, alias);
 170                 alias = NULL;
 171         }
 172
 173         if ((r = device_find_escape_name(m, sysfs, &u)) < 0)
 174                 return r;
 175
 176         if (r == 0 && dn)
 177                 if ((r = device_find_escape_name(m, dn, &u)) < 0)
 178                         return r;
 179
 180         if (r == 0) {
 181                 first = udev_device_get_devlinks_list_entry(dev);
 182                 udev_list_entry_foreach(item, first) {
 183                         if ((r = device_find_escape_name(m, udev_list_entry_get_name(item), &u)) < 0)
 184                                 return r;
 185
 186                         if (r > 0)
 187                                 break;
 188                 }
 189         }
 190
 191         if (r == 0 && alias)
 192                 if ((r = device_find_escape_name(m, alias, &u)) < 0)
 193                         return r;
 194
 195         /* FIXME: this needs proper merging */
 196
 197         assert((r > 0) == !!u);
 198
 199         /* If this is a different unit, then let's not merge things */
 200         if (u && DEVICE(u)->sysfs && !path_equal(DEVICE(u)->sysfs, sysfs))
 201                 u = NULL;
 202
 203         if (!u) {
 204                 delete = true;
 205
 206                 if (!(u = unit_new(m)))
 207                         return -ENOMEM;
 208
 209                 if ((r = device_add_escaped_name(u, sysfs, true)) < 0)
 210                         goto fail;
 211
 212                 unit_add_to_load_queue(u);
 213         } else
 214                 delete = false;
 215
 216         if (!(DEVICE(u)->sysfs))
 217                 if (!(DEVICE(u)->sysfs = strdup(sysfs))) {
 218                         r = -ENOMEM;
 219                         goto fail;
 220                 }
 221
 222         if (alias)
 223                 if ((r = device_add_escaped_name(u, alias, true)) < 0)
 224                         goto fail;
 225
 226         if (dn)
 227                 if ((r = device_add_escaped_name(u, dn, true)) < 0)
 228                         goto fail;
 229
 230         first = udev_device_get_devlinks_list_entry(dev);
 231         udev_list_entry_foreach(item, first)
 232                 if ((r = device_add_escaped_name(u, udev_list_entry_get_name(item), false)) < 0)
 233                         goto fail;
 234
 235         if ((model = udev_device_get_property_value(dev, "ID_MODEL_FROM_DATABASE")) ||
 236             (model = udev_device_get_property_value(dev, "ID_MODEL"))) {
 237                 if ((r = unit_set_description(u, model)) < 0)
 238                         goto fail;
 239         } else if (dn) {
 240                 if ((r = unit_set_description(u, dn)) < 0)
 241                         goto fail;
 242         } else
 243                 if ((r = unit_set_description(u, sysfs)) < 0)
 244                         goto fail;
 245
 246         if (wants) {
 247                 FOREACH_WORD_QUOTED(w, l, wants, state) {
 248                         char *e;
 249
 250                         if (!(e = strndup(w, l))) {
 251                                 r = -ENOMEM;
 252                                 goto fail;
 253                         }
 254
 255                         r = unit_add_dependency_by_name(u, UNIT_WANTS, e, NULL, true);
 256                         free(e);
 257
 258                         if (r < 0)
 259                                 goto fail;
 260                 }
 261         }
 262
 263         if (update_state) {
 264                 manager_dispatch_load_queue(u->meta.manager);
 265                 device_set_state(DEVICE(u), DEVICE_AVAILABLE);
 266         }
 267
 268         unit_add_to_dbus_queue(u);
 269
 270         return 0;
 271
 272 fail:
 273
 274         log_warning("Failed to load device unit: %s", strerror(-r));
 275
 276         if (delete && u)
 277                 unit_free(u);
 278
 279         return r;
 280 }
 281
 282 static int device_process_path(Manager *m, const char *path, bool update_state) {
 283         int r;
 284         struct udev_device *dev;
 285
 286         assert(m);
 287         assert(path);
 288
 289         if (!(dev = udev_device_new_from_syspath(m->udev, path))) {
 290                 log_warning("Failed to get udev device object from udev for path %s.", path);
 291                 return -ENOMEM;
 292         }
 293
 294         r = device_process_new_device(m, dev, update_state);
 295         udev_device_unref(dev);
 296         return r;
 297 }
 298
 299 static int device_process_removed_device(Manager *m, struct udev_device *dev) {
 300         const char *sysfs;
 301         char *e;
 302         Unit *u;
 303         Device *d;
 304
 305         assert(m);
 306         assert(dev);
 307
 308         if (!(sysfs = udev_device_get_syspath(dev)))
 309                 return -ENOMEM;
 310
 311         assert(sysfs[0] == '/');
 312         if (!(e = unit_name_from_path(sysfs, ".device")))
 313                 return -ENOMEM;
 314
 315         u = manager_get_unit(m, e);
 316         free(e);
 317
 318         if (!u)
 319                 return 0;
 320
 321         d = DEVICE(u);
 322         free(d->sysfs);
 323         d->sysfs = NULL;
 324
 325         device_set_state(d, DEVICE_DEAD);
 326         return 0;
 327 }
 328
 329 static void device_shutdown(Manager *m) {
 330         assert(m);
 331
 332         if (m->udev_monitor) {
 333                 udev_monitor_unref(m->udev_monitor);
 334                 m->udev_monitor = NULL;
 335         }
 336
 337         if (m->udev) {
 338                 udev_unref(m->udev);
 339                 m->udev = NULL;
 340         }
 341 }
 342
 343 static int device_enumerate(Manager *m) {
 344         struct epoll_event ev;
 345         int r;
 346         struct udev_enumerate *e = NULL;
 347         struct udev_list_entry *item = NULL, *first = NULL;
 348
 349         assert(m);
 350
 351         if (!m->udev) {
 352                 if (!(m->udev = udev_new()))
 353                         return -ENOMEM;
 354
 355                 if (!(m->udev_monitor = udev_monitor_new_from_netlink(m->udev, "udev"))) {
 356                         r = -ENOMEM;
 357                         goto fail;
 358                 }
 359
 360                 if (udev_monitor_filter_add_match_tag(m->udev_monitor, "systemd") < 0) {
 361                         r = -ENOMEM;
 362                         goto fail;
 363                 }
 364
 365                 if (udev_monitor_enable_receiving(m->udev_monitor) < 0) {
 366                         r = -EIO;
 367                         goto fail;
 368                 }
 369
 370                 m->udev_watch.type = WATCH_UDEV;
 371                 m->udev_watch.fd = udev_monitor_get_fd(m->udev_monitor);
 372
 373                 zero(ev);
 374                 ev.events = EPOLLIN;
 375                 ev.data.ptr = &m->udev_watch;
 376
 377                 if (epoll_ctl(m->epoll_fd, EPOLL_CTL_ADD, m->udev_watch.fd, &ev) < 0)
 378                         return -errno;
 379         }
 380
 381         if (!(e = udev_enumerate_new(m->udev))) {
 382                 r = -ENOMEM;
 383                 goto fail;
 384         }
 385         if (udev_enumerate_add_match_tag(e, "systemd") < 0) {
 386                 r = -EIO;
 387                 goto fail;
 388         }
 389
 390         if (udev_enumerate_scan_devices(e) < 0) {
 391                 r = -EIO;
 392                 goto fail;
 393         }
 394
 395         first = udev_enumerate_get_list_entry(e);
 396         udev_list_entry_foreach(item, first)
 397                 device_process_path(m, udev_list_entry_get_name(item), false);
 398
 399         udev_enumerate_unref(e);
 400         return 0;
 401
 402 fail:
 403         if (e)
 404                 udev_enumerate_unref(e);
 405
 406         device_shutdown(m);
 407         return r;
 408 }
 409
 410 void device_fd_event(Manager *m, int events) {
 411         struct udev_device *dev;
 412         int r;
 413         const char *action;
 414
 415         assert(m);
 416         assert(events == EPOLLIN);
 417
 418         if (!(dev = udev_monitor_receive_device(m->udev_monitor))) {
 419                 log_error("Failed to receive device.");
 420                 return;
 421         }
 422
 423         if (!(action = udev_device_get_action(dev))) {
 424                 log_error("Failed to get udev action string.");
 425                 goto fail;
 426         }
 427
 428         if (streq(action, "remove")) {
 429                 if ((r = device_process_removed_device(m, dev)) < 0) {
 430                         log_error("Failed to process udev device event: %s", strerror(-r));
 431                         goto fail;
 432                 }
 433         } else {
 434                 if ((r = device_process_new_device(m, dev, true)) < 0) {
 435                         log_error("Failed to process udev device event: %s", strerror(-r));
 436                         goto fail;
 437                 }
 438         }
 439
 440 fail:
 441         udev_device_unref(dev);
 442 }
 443
 444 static const char* const device_state_table[_DEVICE_STATE_MAX] = {
 445         [DEVICE_DEAD] = "dead",
 446         [DEVICE_AVAILABLE] = "available"
 447 };
 448
 449 DEFINE_STRING_TABLE_LOOKUP(device_state, DeviceState);
 450
 451 const UnitVTable device_vtable = {
 452         .suffix = ".device",
 453
 454         .no_requires = true,
 455         .no_instances = true,
 456         .no_snapshots = true,
 457         .no_isolate = true,
 458
 459         .load = unit_load_fragment_and_dropin_optional,
 460         .done = device_done,
 461         .coldplug = device_coldplug,
 462
 463         .dump = device_dump,
 464
 465         .active_state = device_active_state,
 466         .sub_state_to_string = device_sub_state_to_string,
 467
 468         .bus_message_handler = bus_device_message_handler,
 469
 470         .enumerate = device_enumerate,
 471         .shutdown = device_shutdown
 472 };