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                           UNIT(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, *expose, *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         int b;
 155
 156         assert(m);
 157
 158         if (!(sysfs = udev_device_get_syspath(dev)))
 159                 return -ENOMEM;
 160
 161         if (!(expose = udev_device_get_property_value(dev, "SYSTEMD_EXPOSE")))
 162                 return 0;
 163
 164         if ((b = parse_boolean(expose)) < 0) {
 165                 log_error("Failed to parse SYSTEMD_EXPOSE udev property for device %s: %s", sysfs, expose);
 166                 return 0;
 167         }
 168
 169         if (!b)
 170                 return 0;
 171
 172         /* Check whether this entry is even relevant for us. */
 173         dn = udev_device_get_devnode(dev);
 174         wants = udev_device_get_property_value(dev, "SYSTEMD_WANTS");
 175         alias = udev_device_get_property_value(dev, "SYSTEMD_ALIAS");
 176
 177         /* We allow exactly one alias to be configured a this time and
 178          * it must be a path */
 179
 180         if (alias && !is_path(alias)) {
 181                 log_warning("SYSTEMD_ALIAS for %s is not a path, ignoring: %s", sysfs, alias);
 182                 alias = NULL;
 183         }
 184
 185         if ((r = device_find_escape_name(m, sysfs, &u)) < 0)
 186                 return r;
 187
 188         if (r == 0 && dn)
 189                 if ((r = device_find_escape_name(m, dn, &u)) < 0)
 190                         return r;
 191
 192         if (r == 0) {
 193                 first = udev_device_get_devlinks_list_entry(dev);
 194                 udev_list_entry_foreach(item, first) {
 195                         if ((r = device_find_escape_name(m, udev_list_entry_get_name(item), &u)) < 0)
 196                                 return r;
 197
 198                         if (r > 0)
 199                                 break;
 200                 }
 201         }
 202
 203         if (r == 0 && alias)
 204                 if ((r = device_find_escape_name(m, alias, &u)) < 0)
 205                         return r;
 206
 207         /* FIXME: this needs proper merging */
 208
 209         assert((r > 0) == !!u);
 210
 211         /* If this is a different unit, then let's not merge things */
 212         if (u && DEVICE(u)->sysfs && !path_equal(DEVICE(u)->sysfs, sysfs))
 213                 u = NULL;
 214
 215         if (!u) {
 216                 delete = true;
 217
 218                 if (!(u = unit_new(m)))
 219                         return -ENOMEM;
 220
 221                 if ((r = device_add_escaped_name(u, sysfs, true)) < 0)
 222                         goto fail;
 223
 224                 unit_add_to_load_queue(u);
 225         } else
 226                 delete = false;
 227
 228         if (!(DEVICE(u)->sysfs))
 229                 if (!(DEVICE(u)->sysfs = strdup(sysfs))) {
 230                         r = -ENOMEM;
 231                         goto fail;
 232                 }
 233
 234         if (alias)
 235                 if ((r = device_add_escaped_name(u, alias, true)) < 0)
 236                         goto fail;
 237
 238         if (dn)
 239                 if ((r = device_add_escaped_name(u, dn, true)) < 0)
 240                         goto fail;
 241
 242         first = udev_device_get_devlinks_list_entry(dev);
 243         udev_list_entry_foreach(item, first)
 244                 if ((r = device_add_escaped_name(u, udev_list_entry_get_name(item), false)) < 0)
 245                         goto fail;
 246
 247         if ((model = udev_device_get_property_value(dev, "ID_MODEL_FROM_DATABASE")) ||
 248             (model = udev_device_get_property_value(dev, "ID_MODEL"))) {
 249                 if ((r = unit_set_description(u, model)) < 0)
 250                         goto fail;
 251         } else if (dn)
 252                 if ((r = unit_set_description(u, dn)) < 0)
 253                         goto fail;
 254
 255         if (wants) {
 256                 FOREACH_WORD(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, NULL, e, 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_AVAILABLE);
 275         }
 276
 277         unit_add_to_dbus_queue(u);
 278
 279         return 0;
 280
 281 fail:
 282         if (delete && u)
 283                 unit_free(u);
 284         return r;
 285 }
 286
 287 static int device_process_path(Manager *m, const char *path, bool update_state) {
 288         int r;
 289         struct udev_device *dev;
 290
 291         assert(m);
 292         assert(path);
 293
 294         if (!(dev = udev_device_new_from_syspath(m->udev, path))) {
 295                 log_warning("Failed to get udev device object from udev for path %s.", path);
 296                 return -ENOMEM;
 297         }
 298
 299         r = device_process_new_device(m, dev, update_state);
 300         udev_device_unref(dev);
 301         return r;
 302 }
 303
 304 static int device_process_removed_device(Manager *m, struct udev_device *dev) {
 305         const char *sysfs;
 306         char *e;
 307         Unit *u;
 308         Device *d;
 309
 310         assert(m);
 311         assert(dev);
 312
 313         if (!(sysfs = udev_device_get_syspath(dev)))
 314                 return -ENOMEM;
 315
 316         assert(sysfs[0] == '/');
 317         if (!(e = unit_name_from_path(sysfs, ".device")))
 318                 return -ENOMEM;
 319
 320         u = manager_get_unit(m, e);
 321         free(e);
 322
 323         if (!u)
 324                 return 0;
 325
 326         d = DEVICE(u);
 327         free(d->sysfs);
 328         d->sysfs = NULL;
 329
 330         device_set_state(d, DEVICE_DEAD);
 331         return 0;
 332 }
 333
 334 static void device_shutdown(Manager *m) {
 335         assert(m);
 336
 337         if (m->udev_monitor) {
 338                 udev_monitor_unref(m->udev_monitor);
 339                 m->udev_monitor = NULL;
 340         }
 341
 342         if (m->udev) {
 343                 udev_unref(m->udev);
 344                 m->udev = NULL;
 345         }
 346 }
 347
 348 static int device_enumerate(Manager *m) {
 349         struct epoll_event ev;
 350         int r;
 351         struct udev_enumerate *e = NULL;
 352         struct udev_list_entry *item = NULL, *first = NULL;
 353
 354         assert(m);
 355
 356         if (!m->udev) {
 357                 if (!(m->udev = udev_new()))
 358                         return -ENOMEM;
 359
 360                 if (!(m->udev_monitor = udev_monitor_new_from_netlink(m->udev, "udev"))) {
 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
 386         if (udev_enumerate_scan_devices(e) < 0) {
 387                 r = -EIO;
 388                 goto fail;
 389         }
 390
 391         first = udev_enumerate_get_list_entry(e);
 392         udev_list_entry_foreach(item, first)
 393                 device_process_path(m, udev_list_entry_get_name(item), false);
 394
 395         udev_enumerate_unref(e);
 396         return 0;
 397
 398 fail:
 399         if (e)
 400                 udev_enumerate_unref(e);
 401
 402         device_shutdown(m);
 403         return r;
 404 }
 405
 406 void device_fd_event(Manager *m, int events) {
 407         struct udev_device *dev;
 408         int r;
 409         const char *action;
 410
 411         assert(m);
 412         assert(events == EPOLLIN);
 413
 414         if (!(dev = udev_monitor_receive_device(m->udev_monitor))) {
 415                 log_error("Failed to receive device.");
 416                 return;
 417         }
 418
 419         if (!(action = udev_device_get_action(dev))) {
 420                 log_error("Failed to get udev action string.");
 421                 goto fail;
 422         }
 423
 424         if (streq(action, "remove")) {
 425                 if ((r = device_process_removed_device(m, dev)) < 0) {
 426                         log_error("Failed to process udev device event: %s", strerror(-r));
 427                         goto fail;
 428                 }
 429         } else {
 430                 if ((r = device_process_new_device(m, dev, true)) < 0) {
 431                         log_error("Failed to process udev device event: %s", strerror(-r));
 432                         goto fail;
 433                 }
 434         }
 435
 436 fail:
 437         udev_device_unref(dev);
 438 }
 439
 440 static const char* const device_state_table[_DEVICE_STATE_MAX] = {
 441         [DEVICE_DEAD] = "dead",
 442         [DEVICE_AVAILABLE] = "available"
 443 };
 444
 445 DEFINE_STRING_TABLE_LOOKUP(device_state, DeviceState);
 446
 447 const UnitVTable device_vtable = {
 448         .suffix = ".device",
 449
 450         .no_requires = true,
 451         .no_instances = true,
 452         .no_snapshots = true,
 453         .no_isolate = true,
 454
 455         .load = unit_load_fragment_and_dropin_optional,
 456         .done = device_done,
 457         .coldplug = device_coldplug,
 458
 459         .dump = device_dump,
 460
 461         .active_state = device_active_state,
 462         .sub_state_to_string = device_sub_state_to_string,
 463
 464         .bus_message_handler = bus_device_message_handler,
 465
 466         .enumerate = device_enumerate,
 467         .shutdown = device_shutdown
 468 };