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         old_state = d->state;
  53         d->state = state;
  54
  55         log_debug("%s changed %s → %s", unit_id(UNIT(d)), state_string_table[old_state], state_string_table[state]);
  56
  57         unit_notify(UNIT(d), state_translation_table[old_state], state_translation_table[state]);
  58 }
  59
  60 static int device_coldplug(Unit *u) {
  61         Device *d = DEVICE(u);
  62
  63         assert(d);
  64         assert(d->state == DEVICE_DEAD);
  65
  66         if (d->sysfs)
  67                 device_set_state(d, DEVICE_AVAILABLE);
  68
  69         return 0;
  70 }
  71
  72 static void device_dump(Unit *u, FILE *f, const char *prefix) {
  73         Device *d = DEVICE(u);
  74
  75         assert(d);
  76
  77         fprintf(f,
  78                 "%sDevice State: %s\n"
  79                 "%sSysfs Path: %s\n",
  80                 prefix, state_string_table[d->state],
  81                 prefix, strna(d->sysfs));
  82 }
  83
  84 static UnitActiveState device_active_state(Unit *u) {
  85         assert(u);
  86
  87         return state_translation_table[DEVICE(u)->state];
  88 }
  89
  90 static int device_add_escaped_name(Unit *u, const char *dn, bool make_id) {
  91         char *e;
  92         int r;
  93
  94         assert(u);
  95         assert(dn);
  96         assert(dn[0] == '/');
  97
  98         if (!(e = unit_name_escape_path(dn+1, ".device")))
  99                 return -ENOMEM;
 100
 101         r = unit_add_name(u, e);
 102
 103         if (r >= 0 && make_id)
 104                 unit_choose_id(u, e);
 105
 106         free(e);
 107
 108         if (r < 0 && r != -EEXIST)
 109                 return r;
 110
 111         return 0;
 112 }
 113
 114 static int device_process_new_device(Manager *m, struct udev_device *dev, bool update_state) {
 115         const char *dn, *names, *wants, *sysfs;
 116         Unit *u = NULL;
 117         int r;
 118         char *e, *w, *state;
 119         size_t l;
 120         bool delete;
 121         struct udev_list_entry *item = NULL, *first = NULL;
 122
 123         assert(m);
 124
 125         /* Check whether this entry is even relevant for us. */
 126         dn = udev_device_get_devnode(dev);
 127         names = udev_device_get_property_value(dev, "SYSTEMD_NAMES");
 128         wants = udev_device_get_property_value(dev, "SYSTEMD_WANTS");
 129
 130         if (!dn && !names && !wants)
 131                 return 0;
 132
 133         /* Ok, seems kinda interesting. Now, let's see if this one
 134          * already exists. */
 135
 136         if (!(sysfs = udev_device_get_syspath(dev)))
 137                 return -ENOMEM;
 138
 139         assert(sysfs[0] == '/');
 140         if (!(e = unit_name_escape_path(sysfs+1, ".device")))
 141                 return -ENOMEM;
 142
 143         if (!(u = manager_get_unit(m, e))) {
 144                 const char *model;
 145
 146                 delete = true;
 147
 148                 if (!(u = unit_new(m))) {
 149                         free(e);
 150                         return -ENOMEM;
 151                 }
 152
 153                 r = unit_add_name(u, e);
 154                 free(e);
 155
 156                 if (r < 0)
 157                         goto fail;
 158
 159                 if (!(DEVICE(u)->sysfs = strdup(sysfs))) {
 160                         r = -ENOMEM;
 161                         goto fail;
 162                 }
 163
 164                 if ((model = udev_device_get_property_value(dev, "ID_MODEL_FROM_DATABASE")) ||
 165                     (model = udev_device_get_property_value(dev, "ID_MODEL"))) {
 166                         if ((r = unit_set_description(u, model)) < 0)
 167                                 goto fail;
 168                 } else if (dn)
 169                         if ((r = unit_set_description(u, dn)) < 0)
 170                                 goto fail;
 171
 172                 unit_add_to_load_queue(u);
 173         } else {
 174                 delete = false;
 175                 free(e);
 176         }
 177
 178         if (dn)
 179                 if ((r = device_add_escaped_name(u, dn, true)) < 0)
 180                         goto fail;
 181
 182         first = udev_device_get_devlinks_list_entry(dev);
 183         udev_list_entry_foreach(item, first)
 184                 if ((r = device_add_escaped_name(u, udev_list_entry_get_name(item), false)) < 0)
 185                         goto fail;
 186
 187         if (names) {
 188                 FOREACH_WORD(w, l, names, state) {
 189                         if (!(e = strndup(w, l))) {
 190                                 r = -ENOMEM;
 191                                 goto fail;
 192                         }
 193
 194                         r = unit_add_name(u, e);
 195                         free(e);
 196
 197                         if (r < 0 && r != -EEXIST)
 198                                 goto fail;
 199                 }
 200         }
 201
 202         if (wants) {
 203                 FOREACH_WORD(w, l, wants, state) {
 204                         if (!(e = strndup(w, l))) {
 205                                 r = -ENOMEM;
 206                                 goto fail;
 207                         }
 208
 209                         r = unit_add_dependency_by_name(u, UNIT_WANTS, e);
 210                         free(e);
 211
 212                         if (r < 0)
 213                                 goto fail;
 214                 }
 215         }
 216
 217         if (update_state) {
 218                 manager_dispatch_load_queue(u->meta.manager);
 219                 device_set_state(DEVICE(u), DEVICE_AVAILABLE);
 220         }
 221
 222         unit_add_to_dbus_queue(u);
 223
 224         return 0;
 225
 226 fail:
 227         if (delete && u)
 228                 unit_free(u);
 229         return r;
 230 }
 231
 232 static int device_process_path(Manager *m, const char *path, bool update_state) {
 233         int r;
 234         struct udev_device *dev;
 235
 236         assert(m);
 237         assert(path);
 238
 239         if (!(dev = udev_device_new_from_syspath(m->udev, path))) {
 240                 log_warning("Failed to get udev device object from udev for path %s.", path);
 241                 return -ENOMEM;
 242         }
 243
 244         r = device_process_new_device(m, dev, update_state);
 245         udev_device_unref(dev);
 246         return r;
 247 }
 248
 249 static int device_process_removed_device(Manager *m, struct udev_device *dev) {
 250         const char *sysfs;
 251         char *e;
 252         Unit *u;
 253         Device *d;
 254
 255         assert(m);
 256         assert(dev);
 257
 258         if (!(sysfs = udev_device_get_syspath(dev)))
 259                 return -ENOMEM;
 260
 261         assert(sysfs[0] == '/');
 262         if (!(e = unit_name_escape_path(sysfs+1, ".device")))
 263                 return -ENOMEM;
 264
 265         u = manager_get_unit(m, e);
 266         free(e);
 267
 268         if (!u)
 269                 return 0;
 270
 271         d = DEVICE(u);
 272         free(d->sysfs);
 273         d->sysfs = NULL;
 274
 275         device_set_state(d, DEVICE_DEAD);
 276         return 0;
 277 }
 278
 279 static void device_shutdown(Manager *m) {
 280         assert(m);
 281
 282         if (m->udev_monitor)
 283                 udev_monitor_unref(m->udev_monitor);
 284
 285         if (m->udev)
 286                 udev_unref(m->udev);
 287 }
 288
 289 static int device_enumerate(Manager *m) {
 290         struct epoll_event ev;
 291         int r;
 292         struct udev_enumerate *e = NULL;
 293         struct udev_list_entry *item = NULL, *first = NULL;
 294
 295         assert(m);
 296
 297         if (!(m->udev = udev_new()))
 298                 return -ENOMEM;
 299
 300         if (!(m->udev_monitor = udev_monitor_new_from_netlink(m->udev, "udev"))) {
 301                 r = -ENOMEM;
 302                 goto fail;
 303         }
 304
 305         if (udev_monitor_enable_receiving(m->udev_monitor) < 0) {
 306                 r = -EIO;
 307                 goto fail;
 308         }
 309
 310         m->udev_watch.type = WATCH_UDEV;
 311         m->udev_watch.fd = udev_monitor_get_fd(m->udev_monitor);
 312
 313         zero(ev);
 314         ev.events = EPOLLIN;
 315         ev.data.ptr = &m->udev_watch;
 316
 317         if (epoll_ctl(m->epoll_fd, EPOLL_CTL_ADD, m->udev_watch.fd, &ev) < 0)
 318                 return -errno;
 319
 320         if (!(e = udev_enumerate_new(m->udev))) {
 321                 r = -ENOMEM;
 322                 goto fail;
 323         }
 324
 325         if (udev_enumerate_scan_devices(e) < 0) {
 326                 r = -EIO;
 327                 goto fail;
 328         }
 329
 330         first = udev_enumerate_get_list_entry(e);
 331         udev_list_entry_foreach(item, first)
 332                 device_process_path(m, udev_list_entry_get_name(item), false);
 333
 334         udev_enumerate_unref(e);
 335         return 0;
 336
 337 fail:
 338         if (e)
 339                 udev_enumerate_unref(e);
 340
 341         device_shutdown(m);
 342         return r;
 343 }
 344
 345 void device_fd_event(Manager *m, int events) {
 346         struct udev_device *dev;
 347         int r;
 348         const char *action;
 349
 350         assert(m);
 351         assert(events == EPOLLIN);
 352
 353         log_debug("got udev event");
 354
 355         if (!(dev = udev_monitor_receive_device(m->udev_monitor))) {
 356                 log_error("Failed to receive device.");
 357                 return;
 358         }
 359
 360         if (!(action = udev_device_get_action(dev))) {
 361                 log_error("Failed to get udev action string.");
 362                 goto fail;
 363         }
 364
 365         if (streq(action, "remove")) {
 366                 if ((r = device_process_removed_device(m, dev)) < 0) {
 367                         log_error("Failed to process udev device event: %s", strerror(-r));
 368                         goto fail;
 369                 }
 370         } else {
 371                 if ((r = device_process_new_device(m, dev, true)) < 0) {
 372                         log_error("Failed to process udev device event: %s", strerror(-r));
 373                         goto fail;
 374                 }
 375         }
 376
 377 fail:
 378         udev_device_unref(dev);
 379 }
 380
 381 const UnitVTable device_vtable = {
 382         .suffix = ".device",
 383
 384         .init = unit_load_fragment_and_dropin_optional,
 385         .done = device_done,
 386         .coldplug = device_coldplug,
 387
 388         .dump = device_dump,
 389
 390         .active_state = device_active_state,
 391
 392         .enumerate = device_enumerate,
 393         .shutdown = device_shutdown
 394 };