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