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, *expose;
 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         if (!(sysfs = udev_device_get_syspath(dev)))
 126                 return -ENOMEM;
 127
 128         /* Check whether this entry is even relevant for us. */
 129         dn = udev_device_get_devnode(dev);
 130         expose = udev_device_get_property_value(dev, "SYSTEMD_EXPOSE");
 131         names = udev_device_get_property_value(dev, "SYSTEMD_NAMES");
 132         wants = udev_device_get_property_value(dev, "SYSTEMD_WANTS");
 133
 134         if (expose) {
 135                 int b;
 136
 137                 if ((b = parse_boolean(expose)) < 0) {
 138                         log_error("Failed to parse SYSTEMD_EXPOSE udev property for device %s: %s", sysfs, expose);
 139                         return 0;
 140                 }
 141
 142                 if (!b)
 143                         return 0;
 144         } else
 145                 if (!dn && !names && !wants)
 146                         return 0;
 147
 148         /* Ok, seems kinda interesting. Now, let's see if this one
 149          * already exists. */
 150
 151         assert(sysfs[0] == '/');
 152         if (!(e = unit_name_escape_path(sysfs+1, ".device")))
 153                 return -ENOMEM;
 154
 155         if (!(u = manager_get_unit(m, e))) {
 156                 const char *model;
 157
 158                 delete = true;
 159
 160                 if (!(u = unit_new(m))) {
 161                         free(e);
 162                         return -ENOMEM;
 163                 }
 164
 165                 r = unit_add_name(u, e);
 166                 free(e);
 167
 168                 if (r < 0)
 169                         goto fail;
 170
 171                 if (!(DEVICE(u)->sysfs = strdup(sysfs))) {
 172                         r = -ENOMEM;
 173                         goto fail;
 174                 }
 175
 176                 if ((model = udev_device_get_property_value(dev, "ID_MODEL_FROM_DATABASE")) ||
 177                     (model = udev_device_get_property_value(dev, "ID_MODEL"))) {
 178                         if ((r = unit_set_description(u, model)) < 0)
 179                                 goto fail;
 180                 } else if (dn)
 181                         if ((r = unit_set_description(u, dn)) < 0)
 182                                 goto fail;
 183
 184                 unit_add_to_load_queue(u);
 185         } else {
 186                 delete = false;
 187                 free(e);
 188         }
 189
 190         if (dn)
 191                 if ((r = device_add_escaped_name(u, dn, true)) < 0)
 192                         goto fail;
 193
 194         first = udev_device_get_devlinks_list_entry(dev);
 195         udev_list_entry_foreach(item, first)
 196                 if ((r = device_add_escaped_name(u, udev_list_entry_get_name(item), false)) < 0)
 197                         goto fail;
 198
 199         if (names) {
 200                 FOREACH_WORD(w, l, names, state) {
 201                         if (!(e = strndup(w, l))) {
 202                                 r = -ENOMEM;
 203                                 goto fail;
 204                         }
 205
 206                         r = unit_add_name(u, e);
 207                         free(e);
 208
 209                         if (r < 0 && r != -EEXIST)
 210                                 goto fail;
 211                 }
 212         }
 213
 214         if (wants) {
 215                 FOREACH_WORD(w, l, wants, state) {
 216                         if (!(e = strndup(w, l))) {
 217                                 r = -ENOMEM;
 218                                 goto fail;
 219                         }
 220
 221                         r = unit_add_dependency_by_name(u, UNIT_WANTS, e);
 222                         free(e);
 223
 224                         if (r < 0)
 225                                 goto fail;
 226                 }
 227         }
 228
 229         if (update_state) {
 230                 manager_dispatch_load_queue(u->meta.manager);
 231                 device_set_state(DEVICE(u), DEVICE_AVAILABLE);
 232         }
 233
 234         unit_add_to_dbus_queue(u);
 235
 236         return 0;
 237
 238 fail:
 239         if (delete && u)
 240                 unit_free(u);
 241         return r;
 242 }
 243
 244 static int device_process_path(Manager *m, const char *path, bool update_state) {
 245         int r;
 246         struct udev_device *dev;
 247
 248         assert(m);
 249         assert(path);
 250
 251         if (!(dev = udev_device_new_from_syspath(m->udev, path))) {
 252                 log_warning("Failed to get udev device object from udev for path %s.", path);
 253                 return -ENOMEM;
 254         }
 255
 256         r = device_process_new_device(m, dev, update_state);
 257         udev_device_unref(dev);
 258         return r;
 259 }
 260
 261 static int device_process_removed_device(Manager *m, struct udev_device *dev) {
 262         const char *sysfs;
 263         char *e;
 264         Unit *u;
 265         Device *d;
 266
 267         assert(m);
 268         assert(dev);
 269
 270         if (!(sysfs = udev_device_get_syspath(dev)))
 271                 return -ENOMEM;
 272
 273         assert(sysfs[0] == '/');
 274         if (!(e = unit_name_escape_path(sysfs+1, ".device")))
 275                 return -ENOMEM;
 276
 277         u = manager_get_unit(m, e);
 278         free(e);
 279
 280         if (!u)
 281                 return 0;
 282
 283         d = DEVICE(u);
 284         free(d->sysfs);
 285         d->sysfs = NULL;
 286
 287         device_set_state(d, DEVICE_DEAD);
 288         return 0;
 289 }
 290
 291 static void device_shutdown(Manager *m) {
 292         assert(m);
 293
 294         if (m->udev_monitor)
 295                 udev_monitor_unref(m->udev_monitor);
 296
 297         if (m->udev)
 298                 udev_unref(m->udev);
 299 }
 300
 301 static int device_enumerate(Manager *m) {
 302         struct epoll_event ev;
 303         int r;
 304         struct udev_enumerate *e = NULL;
 305         struct udev_list_entry *item = NULL, *first = NULL;
 306
 307         assert(m);
 308
 309         if (!(m->udev = udev_new()))
 310                 return -ENOMEM;
 311
 312         if (!(m->udev_monitor = udev_monitor_new_from_netlink(m->udev, "udev"))) {
 313                 r = -ENOMEM;
 314                 goto fail;
 315         }
 316
 317         if (udev_monitor_enable_receiving(m->udev_monitor) < 0) {
 318                 r = -EIO;
 319                 goto fail;
 320         }
 321
 322         m->udev_watch.type = WATCH_UDEV;
 323         m->udev_watch.fd = udev_monitor_get_fd(m->udev_monitor);
 324
 325         zero(ev);
 326         ev.events = EPOLLIN;
 327         ev.data.ptr = &m->udev_watch;
 328
 329         if (epoll_ctl(m->epoll_fd, EPOLL_CTL_ADD, m->udev_watch.fd, &ev) < 0)
 330                 return -errno;
 331
 332         if (!(e = udev_enumerate_new(m->udev))) {
 333                 r = -ENOMEM;
 334                 goto fail;
 335         }
 336
 337         if (udev_enumerate_scan_devices(e) < 0) {
 338                 r = -EIO;
 339                 goto fail;
 340         }
 341
 342         first = udev_enumerate_get_list_entry(e);
 343         udev_list_entry_foreach(item, first)
 344                 device_process_path(m, udev_list_entry_get_name(item), false);
 345
 346         udev_enumerate_unref(e);
 347         return 0;
 348
 349 fail:
 350         if (e)
 351                 udev_enumerate_unref(e);
 352
 353         device_shutdown(m);
 354         return r;
 355 }
 356
 357 void device_fd_event(Manager *m, int events) {
 358         struct udev_device *dev;
 359         int r;
 360         const char *action;
 361
 362         assert(m);
 363         assert(events == EPOLLIN);
 364
 365         if (!(dev = udev_monitor_receive_device(m->udev_monitor))) {
 366                 log_error("Failed to receive device.");
 367                 return;
 368         }
 369
 370         if (!(action = udev_device_get_action(dev))) {
 371                 log_error("Failed to get udev action string.");
 372                 goto fail;
 373         }
 374
 375         if (streq(action, "remove")) {
 376                 if ((r = device_process_removed_device(m, dev)) < 0) {
 377                         log_error("Failed to process udev device event: %s", strerror(-r));
 378                         goto fail;
 379                 }
 380         } else {
 381                 if ((r = device_process_new_device(m, dev, true)) < 0) {
 382                         log_error("Failed to process udev device event: %s", strerror(-r));
 383                         goto fail;
 384                 }
 385         }
 386
 387 fail:
 388         udev_device_unref(dev);
 389 }
 390
 391 const UnitVTable device_vtable = {
 392         .suffix = ".device",
 393
 394         .init = unit_load_fragment_and_dropin_optional,
 395         .done = device_done,
 396         .coldplug = device_coldplug,
 397
 398         .dump = device_dump,
 399
 400         .active_state = device_active_state,
 401
 402         .enumerate = device_enumerate,
 403         .shutdown = device_shutdown
 404 };