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
  31 static const UnitActiveState state_translation_table[_DEVICE_STATE_MAX] = {
  32         [DEVICE_DEAD] = UNIT_INACTIVE,
  33         [DEVICE_AVAILABLE] = UNIT_ACTIVE
  34 };
  35
  36 static const char* const state_string_table[_DEVICE_STATE_MAX] = {
  37         [DEVICE_DEAD] = "dead",
  38         [DEVICE_AVAILABLE] = "available"
  39 };
  40
  41 static void device_done(Unit *u) {
  42         Device *d = DEVICE(u);
  43
  44         assert(d);
  45         free(d->sysfs);
  46 }
  47
  48 static void device_set_state(Device *d, DeviceState state) {
  49         DeviceState old_state;
  50         assert(d);
  51
  52         if (state == d->state)
  53                 return;
  54
  55         old_state = d->state;
  56         d->state = state;
  57
  58         log_debug("%s changed %s → %s", unit_id(UNIT(d)), state_string_table[old_state], state_string_table[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, state_string_table[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 int device_add_escaped_name(Unit *u, const char *dn, bool make_id) {
  94         char *e;
  95         int r;
  96
  97         assert(u);
  98         assert(dn);
  99         assert(dn[0] == '/');
 100
 101         if (!(e = unit_name_escape_path(dn+1, ".device")))
 102                 return -ENOMEM;
 103
 104         r = unit_add_name(u, e);
 105
 106         if (r >= 0 && make_id)
 107                 unit_choose_id(u, e);
 108
 109         free(e);
 110
 111         if (r < 0 && r != -EEXIST)
 112                 return r;
 113
 114         return 0;
 115 }
 116
 117 static int device_find_escape_name(Manager *m, const char *dn, Unit **_u) {
 118         char *e;
 119         Unit *u;
 120
 121         assert(m);
 122         assert(dn);
 123         assert(dn[0] == '/');
 124         assert(_u);
 125
 126         if (!(e = unit_name_escape_path(dn+1, ".device")))
 127                 return -ENOMEM;
 128
 129         u = manager_get_unit(m, e);
 130         free(e);
 131
 132         if (u) {
 133                 *_u = u;
 134                 return 1;
 135         }
 136
 137         return 0;
 138 }
 139
 140 static int device_process_new_device(Manager *m, struct udev_device *dev, bool update_state) {
 141         const char *dn, *names, *wants, *sysfs, *expose, *model;
 142         Unit *u = NULL;
 143         int r;
 144         char *w, *state;
 145         size_t l;
 146         bool delete;
 147         struct udev_list_entry *item = NULL, *first = NULL;
 148
 149         assert(m);
 150
 151         if (!(sysfs = udev_device_get_syspath(dev)))
 152                 return -ENOMEM;
 153
 154         /* Check whether this entry is even relevant for us. */
 155         dn = udev_device_get_devnode(dev);
 156         expose = udev_device_get_property_value(dev, "SYSTEMD_EXPOSE");
 157         names = udev_device_get_property_value(dev, "SYSTEMD_NAMES");
 158         wants = udev_device_get_property_value(dev, "SYSTEMD_WANTS");
 159
 160         if (expose) {
 161                 int b;
 162
 163                 if ((b = parse_boolean(expose)) < 0) {
 164                         log_error("Failed to parse SYSTEMD_EXPOSE udev property for device %s: %s", sysfs, expose);
 165                         return 0;
 166                 }
 167
 168                 if (!b)
 169                         return 0;
 170         } else
 171                 if (!dn && !names && !wants)
 172                         return 0;
 173
 174         /* Ok, seems kinda interesting. Now, let's see if this one
 175          * already exists. */
 176
 177         if ((r = device_find_escape_name(m, sysfs, &u)) < 0)
 178                 return r;
 179
 180         if (r == 0 && dn)
 181                 if ((r = device_find_escape_name(m, dn, &u)) < 0)
 182                         return r;
 183
 184         if (r == 0) {
 185                 first = udev_device_get_devlinks_list_entry(dev);
 186                 udev_list_entry_foreach(item, first) {
 187                         if ((r = device_find_escape_name(m, udev_list_entry_get_name(item), &u)) < 0)
 188                                 return r;
 189
 190                         if (r > 0)
 191                                 break;
 192                 }
 193         }
 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 && !streq(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                 if (!(DEVICE(u)->sysfs = strdup(sysfs))) {
 213                         r = -ENOMEM;
 214                         goto fail;
 215                 }
 216
 217                 unit_add_to_load_queue(u);
 218         } else
 219                 delete = false;
 220
 221         if (dn)
 222                 if ((r = device_add_escaped_name(u, dn, true)) < 0)
 223                         goto fail;
 224
 225         first = udev_device_get_devlinks_list_entry(dev);
 226         udev_list_entry_foreach(item, first)
 227                 if ((r = device_add_escaped_name(u, udev_list_entry_get_name(item), false)) < 0)
 228                         goto fail;
 229
 230         if ((model = udev_device_get_property_value(dev, "ID_MODEL_FROM_DATABASE")) ||
 231             (model = udev_device_get_property_value(dev, "ID_MODEL"))) {
 232                 if ((r = unit_set_description(u, model)) < 0)
 233                         goto fail;
 234         } else if (dn)
 235                 if ((r = unit_set_description(u, dn)) < 0)
 236                         goto fail;
 237
 238         /* We don't remove names that are gone. But that should be
 239          * fine and should probably be fixed only on a configuration
 240          * refresh. */
 241
 242         if (names) {
 243                 FOREACH_WORD(w, l, names, state) {
 244                         char *e;
 245
 246                         if (!(e = strndup(w, l))) {
 247                                 r = -ENOMEM;
 248                                 goto fail;
 249                         }
 250
 251                         r = unit_add_name(u, e);
 252                         free(e);
 253
 254                         if (r < 0 && r != -EEXIST)
 255                                 goto fail;
 256                 }
 257         }
 258
 259         if (wants) {
 260                 FOREACH_WORD(w, l, wants, state) {
 261                         char *e;
 262
 263                         if (!(e = strndup(w, l))) {
 264                                 r = -ENOMEM;
 265                                 goto fail;
 266                         }
 267
 268                         r = unit_add_dependency_by_name(u, UNIT_WANTS, e);
 269                         free(e);
 270
 271                         if (r < 0)
 272                                 goto fail;
 273                 }
 274         }
 275
 276         if (update_state) {
 277                 manager_dispatch_load_queue(u->meta.manager);
 278                 device_set_state(DEVICE(u), DEVICE_AVAILABLE);
 279         }
 280
 281         unit_add_to_dbus_queue(u);
 282
 283         return 0;
 284
 285 fail:
 286         if (delete && u)
 287                 unit_free(u);
 288         return r;
 289 }
 290
 291 static int device_process_path(Manager *m, const char *path, bool update_state) {
 292         int r;
 293         struct udev_device *dev;
 294
 295         assert(m);
 296         assert(path);
 297
 298         if (!(dev = udev_device_new_from_syspath(m->udev, path))) {
 299                 log_warning("Failed to get udev device object from udev for path %s.", path);
 300                 return -ENOMEM;
 301         }
 302
 303         r = device_process_new_device(m, dev, update_state);
 304         udev_device_unref(dev);
 305         return r;
 306 }
 307
 308 static int device_process_removed_device(Manager *m, struct udev_device *dev) {
 309         const char *sysfs;
 310         char *e;
 311         Unit *u;
 312         Device *d;
 313
 314         assert(m);
 315         assert(dev);
 316
 317         if (!(sysfs = udev_device_get_syspath(dev)))
 318                 return -ENOMEM;
 319
 320         assert(sysfs[0] == '/');
 321         if (!(e = unit_name_escape_path(sysfs+1, ".device")))
 322                 return -ENOMEM;
 323
 324         u = manager_get_unit(m, e);
 325         free(e);
 326
 327         if (!u)
 328                 return 0;
 329
 330         d = DEVICE(u);
 331         free(d->sysfs);
 332         d->sysfs = NULL;
 333
 334         device_set_state(d, DEVICE_DEAD);
 335         return 0;
 336 }
 337
 338 static void device_shutdown(Manager *m) {
 339         assert(m);
 340
 341         if (m->udev_monitor)
 342                 udev_monitor_unref(m->udev_monitor);
 343
 344         if (m->udev)
 345                 udev_unref(m->udev);
 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 = udev_new()))
 357                 return -ENOMEM;
 358
 359         if (!(m->udev_monitor = udev_monitor_new_from_netlink(m->udev, "udev"))) {
 360                 r = -ENOMEM;
 361                 goto fail;
 362         }
 363
 364         if (udev_monitor_enable_receiving(m->udev_monitor) < 0) {
 365                 r = -EIO;
 366                 goto fail;
 367         }
 368
 369         m->udev_watch.type = WATCH_UDEV;
 370         m->udev_watch.fd = udev_monitor_get_fd(m->udev_monitor);
 371
 372         zero(ev);
 373         ev.events = EPOLLIN;
 374         ev.data.ptr = &m->udev_watch;
 375
 376         if (epoll_ctl(m->epoll_fd, EPOLL_CTL_ADD, m->udev_watch.fd, &ev) < 0)
 377                 return -errno;
 378
 379         if (!(e = udev_enumerate_new(m->udev))) {
 380                 r = -ENOMEM;
 381                 goto fail;
 382         }
 383
 384         if (udev_enumerate_scan_devices(e) < 0) {
 385                 r = -EIO;
 386                 goto fail;
 387         }
 388
 389         first = udev_enumerate_get_list_entry(e);
 390         udev_list_entry_foreach(item, first)
 391                 device_process_path(m, udev_list_entry_get_name(item), false);
 392
 393         udev_enumerate_unref(e);
 394         return 0;
 395
 396 fail:
 397         if (e)
 398                 udev_enumerate_unref(e);
 399
 400         device_shutdown(m);
 401         return r;
 402 }
 403
 404 void device_fd_event(Manager *m, int events) {
 405         struct udev_device *dev;
 406         int r;
 407         const char *action;
 408
 409         assert(m);
 410         assert(events == EPOLLIN);
 411
 412         if (!(dev = udev_monitor_receive_device(m->udev_monitor))) {
 413                 log_error("Failed to receive device.");
 414                 return;
 415         }
 416
 417         if (!(action = udev_device_get_action(dev))) {
 418                 log_error("Failed to get udev action string.");
 419                 goto fail;
 420         }
 421
 422         if (streq(action, "remove")) {
 423                 if ((r = device_process_removed_device(m, dev)) < 0) {
 424                         log_error("Failed to process udev device event: %s", strerror(-r));
 425                         goto fail;
 426                 }
 427         } else {
 428                 if ((r = device_process_new_device(m, dev, true)) < 0) {
 429                         log_error("Failed to process udev device event: %s", strerror(-r));
 430                         goto fail;
 431                 }
 432         }
 433
 434 fail:
 435         udev_device_unref(dev);
 436 }
 437
 438 const UnitVTable device_vtable = {
 439         .suffix = ".device",
 440
 441         .init = unit_load_fragment_and_dropin_optional,
 442         .done = device_done,
 443         .coldplug = device_coldplug,
 444
 445         .dump = device_dump,
 446
 447         .active_state = device_active_state,
 448
 449         .enumerate = device_enumerate,
 450         .shutdown = device_shutdown
 451 };