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 int device_process_new_device(Manager *m, struct udev_device *dev, bool update_state) {
 157         const char *dn, *names, *wants, *sysfs, *expose, *model;
 158         Unit *u = NULL;
 159         int r;
 160         char *w, *state;
 161         size_t l;
 162         bool delete;
 163         struct udev_list_entry *item = NULL, *first = NULL;
 164         int b;
 165
 166         assert(m);
 167
 168         if (!(sysfs = udev_device_get_syspath(dev)))
 169                 return -ENOMEM;
 170
 171         if (!(expose = udev_device_get_property_value(dev, "SYSTEMD_EXPOSE")))
 172                 return 0;
 173
 174         if ((b = parse_boolean(expose)) < 0) {
 175                 log_error("Failed to parse SYSTEMD_EXPOSE udev property for device %s: %s", sysfs, expose);
 176                 return 0;
 177         }
 178
 179         if (!b)
 180                 return 0;
 181
 182         /* Check whether this entry is even relevant for us. */
 183         dn = udev_device_get_devnode(dev);
 184         names = udev_device_get_property_value(dev, "SYSTEMD_NAMES");
 185         wants = udev_device_get_property_value(dev, "SYSTEMD_WANTS");
 186
 187         if ((r = device_find_escape_name(m, sysfs, &u)) < 0)
 188                 return r;
 189
 190         if (r == 0 && dn)
 191                 if ((r = device_find_escape_name(m, dn, &u)) < 0)
 192                         return r;
 193
 194         if (r == 0) {
 195                 first = udev_device_get_devlinks_list_entry(dev);
 196                 udev_list_entry_foreach(item, first) {
 197                         if ((r = device_find_escape_name(m, udev_list_entry_get_name(item), &u)) < 0)
 198                                 return r;
 199
 200                         if (r > 0)
 201                                 break;
 202                 }
 203         }
 204
 205         /* FIXME: this needs proper merging */
 206
 207         assert((r > 0) == !!u);
 208
 209         /* If this is a different unit, then let's not merge things */
 210         if (u && DEVICE(u)->sysfs && !streq(DEVICE(u)->sysfs, sysfs))
 211                 u = NULL;
 212
 213         if (!u) {
 214                 delete = true;
 215
 216                 if (!(u = unit_new(m)))
 217                         return -ENOMEM;
 218
 219                 if ((r = device_add_escaped_name(u, sysfs, true)) < 0)
 220                         goto fail;
 221
 222                 unit_add_to_load_queue(u);
 223         } else
 224                 delete = false;
 225
 226         if (!(DEVICE(u)->sysfs))
 227                 if (!(DEVICE(u)->sysfs = strdup(sysfs))) {
 228                         r = -ENOMEM;
 229                         goto fail;
 230                 }
 231
 232         if (dn)
 233                 if ((r = device_add_escaped_name(u, dn, true)) < 0)
 234                         goto fail;
 235
 236         first = udev_device_get_devlinks_list_entry(dev);
 237         udev_list_entry_foreach(item, first)
 238                 if ((r = device_add_escaped_name(u, udev_list_entry_get_name(item), false)) < 0)
 239                         goto fail;
 240
 241         if ((model = udev_device_get_property_value(dev, "ID_MODEL_FROM_DATABASE")) ||
 242             (model = udev_device_get_property_value(dev, "ID_MODEL"))) {
 243                 if ((r = unit_set_description(u, model)) < 0)
 244                         goto fail;
 245         } else if (dn)
 246                 if ((r = unit_set_description(u, dn)) < 0)
 247                         goto fail;
 248
 249         /* We don't remove names that are gone. But that should be
 250          * fine and should probably be fixed only on a configuration
 251          * refresh. */
 252
 253         if (names) {
 254                 FOREACH_WORD(w, l, names, state) {
 255                         char *e;
 256
 257                         if (!(e = strndup(w, l))) {
 258                                 r = -ENOMEM;
 259                                 goto fail;
 260                         }
 261
 262                         r = unit_add_name(u, e);
 263                         free(e);
 264
 265                         if (r < 0 && r != -EEXIST)
 266                                 goto fail;
 267                 }
 268         }
 269
 270         if (wants) {
 271                 FOREACH_WORD(w, l, wants, state) {
 272                         char *e;
 273
 274                         if (!(e = strndup(w, l))) {
 275                                 r = -ENOMEM;
 276                                 goto fail;
 277                         }
 278
 279                         r = unit_add_dependency_by_name(u, UNIT_WANTS, NULL, e);
 280                         free(e);
 281
 282                         if (r < 0)
 283                                 goto fail;
 284                 }
 285         }
 286
 287         if (update_state) {
 288                 manager_dispatch_load_queue(u->meta.manager);
 289                 device_set_state(DEVICE(u), DEVICE_AVAILABLE);
 290         }
 291
 292         unit_add_to_dbus_queue(u);
 293
 294         return 0;
 295
 296 fail:
 297         if (delete && u)
 298                 unit_free(u);
 299         return r;
 300 }
 301
 302 static int device_process_path(Manager *m, const char *path, bool update_state) {
 303         int r;
 304         struct udev_device *dev;
 305
 306         assert(m);
 307         assert(path);
 308
 309         if (!(dev = udev_device_new_from_syspath(m->udev, path))) {
 310                 log_warning("Failed to get udev device object from udev for path %s.", path);
 311                 return -ENOMEM;
 312         }
 313
 314         r = device_process_new_device(m, dev, update_state);
 315         udev_device_unref(dev);
 316         return r;
 317 }
 318
 319 static int device_process_removed_device(Manager *m, struct udev_device *dev) {
 320         const char *sysfs;
 321         char *e;
 322         Unit *u;
 323         Device *d;
 324
 325         assert(m);
 326         assert(dev);
 327
 328         if (!(sysfs = udev_device_get_syspath(dev)))
 329                 return -ENOMEM;
 330
 331         assert(sysfs[0] == '/');
 332         if (!(e = unit_name_build_escape(sysfs+1, NULL, ".device")))
 333                 return -ENOMEM;
 334
 335         u = manager_get_unit(m, e);
 336         free(e);
 337
 338         if (!u)
 339                 return 0;
 340
 341         d = DEVICE(u);
 342         free(d->sysfs);
 343         d->sysfs = NULL;
 344
 345         device_set_state(d, DEVICE_DEAD);
 346         return 0;
 347 }
 348
 349 static void device_shutdown(Manager *m) {
 350         assert(m);
 351
 352         if (m->udev_monitor)
 353                 udev_monitor_unref(m->udev_monitor);
 354
 355         if (m->udev)
 356                 udev_unref(m->udev);
 357 }
 358
 359 static int device_enumerate(Manager *m) {
 360         struct epoll_event ev;
 361         int r;
 362         struct udev_enumerate *e = NULL;
 363         struct udev_list_entry *item = NULL, *first = NULL;
 364
 365         assert(m);
 366
 367         if (!(m->udev = udev_new()))
 368                 return -ENOMEM;
 369
 370         if (!(m->udev_monitor = udev_monitor_new_from_netlink(m->udev, "udev"))) {
 371                 r = -ENOMEM;
 372                 goto fail;
 373         }
 374
 375         if (udev_monitor_enable_receiving(m->udev_monitor) < 0) {
 376                 r = -EIO;
 377                 goto fail;
 378         }
 379
 380         m->udev_watch.type = WATCH_UDEV;
 381         m->udev_watch.fd = udev_monitor_get_fd(m->udev_monitor);
 382
 383         zero(ev);
 384         ev.events = EPOLLIN;
 385         ev.data.ptr = &m->udev_watch;
 386
 387         if (epoll_ctl(m->epoll_fd, EPOLL_CTL_ADD, m->udev_watch.fd, &ev) < 0)
 388                 return -errno;
 389
 390         if (!(e = udev_enumerate_new(m->udev))) {
 391                 r = -ENOMEM;
 392                 goto fail;
 393         }
 394
 395         if (udev_enumerate_scan_devices(e) < 0) {
 396                 r = -EIO;
 397                 goto fail;
 398         }
 399
 400         first = udev_enumerate_get_list_entry(e);
 401         udev_list_entry_foreach(item, first)
 402                 device_process_path(m, udev_list_entry_get_name(item), false);
 403
 404         udev_enumerate_unref(e);
 405         return 0;
 406
 407 fail:
 408         if (e)
 409                 udev_enumerate_unref(e);
 410
 411         device_shutdown(m);
 412         return r;
 413 }
 414
 415 void device_fd_event(Manager *m, int events) {
 416         struct udev_device *dev;
 417         int r;
 418         const char *action;
 419
 420         assert(m);
 421         assert(events == EPOLLIN);
 422
 423         if (!(dev = udev_monitor_receive_device(m->udev_monitor))) {
 424                 log_error("Failed to receive device.");
 425                 return;
 426         }
 427
 428         if (!(action = udev_device_get_action(dev))) {
 429                 log_error("Failed to get udev action string.");
 430                 goto fail;
 431         }
 432
 433         if (streq(action, "remove")) {
 434                 if ((r = device_process_removed_device(m, dev)) < 0) {
 435                         log_error("Failed to process udev device event: %s", strerror(-r));
 436                         goto fail;
 437                 }
 438         } else {
 439                 if ((r = device_process_new_device(m, dev, true)) < 0) {
 440                         log_error("Failed to process udev device event: %s", strerror(-r));
 441                         goto fail;
 442                 }
 443         }
 444
 445 fail:
 446         udev_device_unref(dev);
 447 }
 448
 449 const UnitVTable device_vtable = {
 450         .suffix = ".device",
 451
 452         .no_requires = true,
 453         .no_instances = true,
 454         .no_snapshots = true,
 455
 456         .init = device_init,
 457         .load = unit_load_fragment_and_dropin_optional,
 458         .done = device_done,
 459         .coldplug = device_coldplug,
 460
 461         .dump = device_dump,
 462
 463         .active_state = device_active_state,
 464         .sub_state_to_string = device_sub_state_to_string,
 465
 466         .enumerate = device_enumerate,
 467         .shutdown = device_shutdown
 468 };