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
  32 static const UnitActiveState state_translation_table[_DEVICE_STATE_MAX] = {
  33         [DEVICE_DEAD] = UNIT_INACTIVE,
  34         [DEVICE_AVAILABLE] = UNIT_ACTIVE
  35 };
  36
  37 static const char* const state_string_table[_DEVICE_STATE_MAX] = {
  38         [DEVICE_DEAD] = "dead",
  39         [DEVICE_AVAILABLE] = "available"
  40 };
  41
  42 static void device_done(Unit *u) {
  43         Device *d = DEVICE(u);
  44
  45         assert(d);
  46
  47         free(d->sysfs);
  48         d->sysfs = NULL;
  49 }
  50
  51 static void device_init(Unit *u) {
  52         Device *d = DEVICE(u);
  53
  54         assert(d);
  55         assert(u->meta.load_state == UNIT_STUB);
  56
  57         d->state = 0;
  58 }
  59
  60 static void device_set_state(Device *d, DeviceState state) {
  61         DeviceState old_state;
  62         assert(d);
  63
  64         old_state = d->state;
  65         d->state = state;
  66
  67         if (state != old_state)
  68                 log_debug("%s changed %s → %s", UNIT(d)->meta.id, state_string_table[old_state], state_string_table[state]);
  69
  70         unit_notify(UNIT(d), state_translation_table[old_state], state_translation_table[state]);
  71 }
  72
  73 static int device_coldplug(Unit *u) {
  74         Device *d = DEVICE(u);
  75
  76         assert(d);
  77         assert(d->state == DEVICE_DEAD);
  78
  79         if (d->sysfs)
  80                 device_set_state(d, DEVICE_AVAILABLE);
  81
  82         return 0;
  83 }
  84
  85 static void device_dump(Unit *u, FILE *f, const char *prefix) {
  86         Device *d = DEVICE(u);
  87
  88         assert(d);
  89
  90         fprintf(f,
  91                 "%sDevice State: %s\n"
  92                 "%sSysfs Path: %s\n",
  93                 prefix, state_string_table[d->state],
  94                 prefix, strna(d->sysfs));
  95 }
  96
  97 static UnitActiveState device_active_state(Unit *u) {
  98         assert(u);
  99
 100         return state_translation_table[DEVICE(u)->state];
 101 }
 102
 103 static const char *device_sub_state_to_string(Unit *u) {
 104         assert(u);
 105
 106         return state_string_table[DEVICE(u)->state];
 107 }
 108
 109 static int device_add_escaped_name(Unit *u, const char *dn, bool make_id) {
 110         char *e;
 111         int r;
 112
 113         assert(u);
 114         assert(dn);
 115         assert(dn[0] == '/');
 116
 117         if (!(e = unit_name_build_escape(dn+1, NULL, ".device")))
 118                 return -ENOMEM;
 119
 120         r = unit_add_name(u, e);
 121
 122         if (r >= 0 && make_id)
 123                 unit_choose_id(u, e);
 124
 125         free(e);
 126
 127         if (r < 0 && r != -EEXIST)
 128                 return r;
 129
 130         return 0;
 131 }
 132
 133 static int device_find_escape_name(Manager *m, const char *dn, Unit **_u) {
 134         char *e;
 135         Unit *u;
 136
 137         assert(m);
 138         assert(dn);
 139         assert(dn[0] == '/');
 140         assert(_u);
 141
 142         if (!(e = unit_name_build_escape(dn+1, NULL, ".device")))
 143                 return -ENOMEM;
 144
 145         u = manager_get_unit(m, e);
 146         free(e);
 147
 148         if (u) {
 149                 *_u = u;
 150                 return 1;
 151         }
 152
 153         return 0;
 154 }
 155
 156 static bool devnode_is_api(const char *node) {
 157         unsigned i;
 158
 159         static const char * const table[] = {
 160                 "/dev/null",
 161                 "/dev/zero",
 162                 "/dev/urandom",
 163                 "/dev/random",
 164                 "/dev/port",
 165                 "/dev/oldmem",
 166                 "/dev/full",
 167                 "/dev/kmsg",
 168                 "/dev/mem"
 169         };
 170
 171         for (i = 0; i < ELEMENTSOF(table); i++)
 172                 if (streq(table[i], node))
 173                         return true;
 174
 175         return false;
 176 }
 177
 178 static int device_process_new_device(Manager *m, struct udev_device *dev, bool update_state) {
 179         const char *dn, *names, *wants, *sysfs, *expose, *model;
 180         Unit *u = NULL;
 181         int r;
 182         char *w, *state;
 183         size_t l;
 184         bool delete;
 185         struct udev_list_entry *item = NULL, *first = NULL;
 186
 187         assert(m);
 188
 189         if (!(sysfs = udev_device_get_syspath(dev)))
 190                 return -ENOMEM;
 191
 192         /* Check whether this entry is even relevant for us. */
 193         dn = udev_device_get_devnode(dev);
 194         expose = udev_device_get_property_value(dev, "SYSTEMD_EXPOSE");
 195         names = udev_device_get_property_value(dev, "SYSTEMD_NAMES");
 196         wants = udev_device_get_property_value(dev, "SYSTEMD_WANTS");
 197
 198         if (expose) {
 199                 int b;
 200
 201                 if ((b = parse_boolean(expose)) < 0) {
 202                         log_error("Failed to parse SYSTEMD_EXPOSE udev property for device %s: %s", sysfs, expose);
 203                         return 0;
 204                 }
 205
 206                 if (!b)
 207                         return 0;
 208         } else
 209                 if ((!dn || devnode_is_api(dn)) && !names && !wants)
 210                         return 0;
 211
 212         /* Ok, seems kinda interesting. Now, let's see if this one
 213          * already exists. */
 214
 215         if ((r = device_find_escape_name(m, sysfs, &u)) < 0)
 216                 return r;
 217
 218         if (r == 0 && dn)
 219                 if ((r = device_find_escape_name(m, dn, &u)) < 0)
 220                         return r;
 221
 222         if (r == 0) {
 223                 first = udev_device_get_devlinks_list_entry(dev);
 224                 udev_list_entry_foreach(item, first) {
 225                         if ((r = device_find_escape_name(m, udev_list_entry_get_name(item), &u)) < 0)
 226                                 return r;
 227
 228                         if (r > 0)
 229                                 break;
 230                 }
 231         }
 232
 233         /* FIXME: this needs proper merging */
 234
 235         assert((r > 0) == !!u);
 236
 237         /* If this is a different unit, then let's not merge things */
 238         if (u && DEVICE(u)->sysfs && !streq(DEVICE(u)->sysfs, sysfs))
 239                 u = NULL;
 240
 241         if (!u) {
 242                 delete = true;
 243
 244                 if (!(u = unit_new(m)))
 245                         return -ENOMEM;
 246
 247                 if ((r = device_add_escaped_name(u, sysfs, true)) < 0)
 248                         goto fail;
 249
 250                 unit_add_to_load_queue(u);
 251         } else
 252                 delete = false;
 253
 254         if (!(DEVICE(u)->sysfs))
 255                 if (!(DEVICE(u)->sysfs = strdup(sysfs))) {
 256                         r = -ENOMEM;
 257                         goto fail;
 258                 }
 259
 260         if (dn)
 261                 if ((r = device_add_escaped_name(u, dn, true)) < 0)
 262                         goto fail;
 263
 264         first = udev_device_get_devlinks_list_entry(dev);
 265         udev_list_entry_foreach(item, first)
 266                 if ((r = device_add_escaped_name(u, udev_list_entry_get_name(item), false)) < 0)
 267                         goto fail;
 268
 269         if ((model = udev_device_get_property_value(dev, "ID_MODEL_FROM_DATABASE")) ||
 270             (model = udev_device_get_property_value(dev, "ID_MODEL"))) {
 271                 if ((r = unit_set_description(u, model)) < 0)
 272                         goto fail;
 273         } else if (dn)
 274                 if ((r = unit_set_description(u, dn)) < 0)
 275                         goto fail;
 276
 277         /* We don't remove names that are gone. But that should be
 278          * fine and should probably be fixed only on a configuration
 279          * refresh. */
 280
 281         if (names) {
 282                 FOREACH_WORD(w, l, names, state) {
 283                         char *e;
 284
 285                         if (!(e = strndup(w, l))) {
 286                                 r = -ENOMEM;
 287                                 goto fail;
 288                         }
 289
 290                         r = unit_add_name(u, e);
 291                         free(e);
 292
 293                         if (r < 0 && r != -EEXIST)
 294                                 goto fail;
 295                 }
 296         }
 297
 298         if (wants) {
 299                 FOREACH_WORD(w, l, wants, state) {
 300                         char *e;
 301
 302                         if (!(e = strndup(w, l))) {
 303                                 r = -ENOMEM;
 304                                 goto fail;
 305                         }
 306
 307                         r = unit_add_dependency_by_name(u, UNIT_WANTS, NULL, e);
 308                         free(e);
 309
 310                         if (r < 0)
 311                                 goto fail;
 312                 }
 313         }
 314
 315         if (update_state) {
 316                 manager_dispatch_load_queue(u->meta.manager);
 317                 device_set_state(DEVICE(u), DEVICE_AVAILABLE);
 318         }
 319
 320         unit_add_to_dbus_queue(u);
 321
 322         return 0;
 323
 324 fail:
 325         if (delete && u)
 326                 unit_free(u);
 327         return r;
 328 }
 329
 330 static int device_process_path(Manager *m, const char *path, bool update_state) {
 331         int r;
 332         struct udev_device *dev;
 333
 334         assert(m);
 335         assert(path);
 336
 337         if (!(dev = udev_device_new_from_syspath(m->udev, path))) {
 338                 log_warning("Failed to get udev device object from udev for path %s.", path);
 339                 return -ENOMEM;
 340         }
 341
 342         r = device_process_new_device(m, dev, update_state);
 343         udev_device_unref(dev);
 344         return r;
 345 }
 346
 347 static int device_process_removed_device(Manager *m, struct udev_device *dev) {
 348         const char *sysfs;
 349         char *e;
 350         Unit *u;
 351         Device *d;
 352
 353         assert(m);
 354         assert(dev);
 355
 356         if (!(sysfs = udev_device_get_syspath(dev)))
 357                 return -ENOMEM;
 358
 359         assert(sysfs[0] == '/');
 360         if (!(e = unit_name_build_escape(sysfs+1, NULL, ".device")))
 361                 return -ENOMEM;
 362
 363         u = manager_get_unit(m, e);
 364         free(e);
 365
 366         if (!u)
 367                 return 0;
 368
 369         d = DEVICE(u);
 370         free(d->sysfs);
 371         d->sysfs = NULL;
 372
 373         device_set_state(d, DEVICE_DEAD);
 374         return 0;
 375 }
 376
 377 static void device_shutdown(Manager *m) {
 378         assert(m);
 379
 380         if (m->udev_monitor)
 381                 udev_monitor_unref(m->udev_monitor);
 382
 383         if (m->udev)
 384                 udev_unref(m->udev);
 385 }
 386
 387 static int device_enumerate(Manager *m) {
 388         struct epoll_event ev;
 389         int r;
 390         struct udev_enumerate *e = NULL;
 391         struct udev_list_entry *item = NULL, *first = NULL;
 392
 393         assert(m);
 394
 395         if (!(m->udev = udev_new()))
 396                 return -ENOMEM;
 397
 398         if (!(m->udev_monitor = udev_monitor_new_from_netlink(m->udev, "udev"))) {
 399                 r = -ENOMEM;
 400                 goto fail;
 401         }
 402
 403         if (udev_monitor_enable_receiving(m->udev_monitor) < 0) {
 404                 r = -EIO;
 405                 goto fail;
 406         }
 407
 408         m->udev_watch.type = WATCH_UDEV;
 409         m->udev_watch.fd = udev_monitor_get_fd(m->udev_monitor);
 410
 411         zero(ev);
 412         ev.events = EPOLLIN;
 413         ev.data.ptr = &m->udev_watch;
 414
 415         if (epoll_ctl(m->epoll_fd, EPOLL_CTL_ADD, m->udev_watch.fd, &ev) < 0)
 416                 return -errno;
 417
 418         if (!(e = udev_enumerate_new(m->udev))) {
 419                 r = -ENOMEM;
 420                 goto fail;
 421         }
 422
 423         if (udev_enumerate_scan_devices(e) < 0) {
 424                 r = -EIO;
 425                 goto fail;
 426         }
 427
 428         first = udev_enumerate_get_list_entry(e);
 429         udev_list_entry_foreach(item, first)
 430                 device_process_path(m, udev_list_entry_get_name(item), false);
 431
 432         udev_enumerate_unref(e);
 433         return 0;
 434
 435 fail:
 436         if (e)
 437                 udev_enumerate_unref(e);
 438
 439         device_shutdown(m);
 440         return r;
 441 }
 442
 443 void device_fd_event(Manager *m, int events) {
 444         struct udev_device *dev;
 445         int r;
 446         const char *action;
 447
 448         assert(m);
 449         assert(events == EPOLLIN);
 450
 451         if (!(dev = udev_monitor_receive_device(m->udev_monitor))) {
 452                 log_error("Failed to receive device.");
 453                 return;
 454         }
 455
 456         if (!(action = udev_device_get_action(dev))) {
 457                 log_error("Failed to get udev action string.");
 458                 goto fail;
 459         }
 460
 461         if (streq(action, "remove")) {
 462                 if ((r = device_process_removed_device(m, dev)) < 0) {
 463                         log_error("Failed to process udev device event: %s", strerror(-r));
 464                         goto fail;
 465                 }
 466         } else {
 467                 if ((r = device_process_new_device(m, dev, true)) < 0) {
 468                         log_error("Failed to process udev device event: %s", strerror(-r));
 469                         goto fail;
 470                 }
 471         }
 472
 473 fail:
 474         udev_device_unref(dev);
 475 }
 476
 477 const UnitVTable device_vtable = {
 478         .suffix = ".device",
 479
 480         .no_requires = true,
 481         .no_instances = true,
 482
 483         .init = device_init,
 484         .load = unit_load_fragment_and_dropin_optional,
 485         .done = device_done,
 486         .coldplug = device_coldplug,
 487
 488         .dump = device_dump,
 489
 490         .active_state = device_active_state,
 491         .sub_state_to_string = device_sub_state_to_string,
 492
 493         .enumerate = device_enumerate,
 494         .shutdown = device_shutdown
 495 };