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_process_new_device(Manager *m, struct udev_device *dev, bool update_state) {
 118         const char *dn, *names, *wants, *sysfs, *expose;
 119         Unit *u = NULL;
 120         int r;
 121         char *e, *w, *state;
 122         size_t l;
 123         bool delete;
 124         struct udev_list_entry *item = NULL, *first = NULL;
 125
 126         assert(m);
 127
 128         if (!(sysfs = udev_device_get_syspath(dev)))
 129                 return -ENOMEM;
 130
 131         /* Check whether this entry is even relevant for us. */
 132         dn = udev_device_get_devnode(dev);
 133         expose = udev_device_get_property_value(dev, "SYSTEMD_EXPOSE");
 134         names = udev_device_get_property_value(dev, "SYSTEMD_NAMES");
 135         wants = udev_device_get_property_value(dev, "SYSTEMD_WANTS");
 136
 137         if (expose) {
 138                 int b;
 139
 140                 if ((b = parse_boolean(expose)) < 0) {
 141                         log_error("Failed to parse SYSTEMD_EXPOSE udev property for device %s: %s", sysfs, expose);
 142                         return 0;
 143                 }
 144
 145                 if (!b)
 146                         return 0;
 147         } else
 148                 if (!dn && !names && !wants)
 149                         return 0;
 150
 151         /* Ok, seems kinda interesting. Now, let's see if this one
 152          * already exists. */
 153
 154         assert(sysfs[0] == '/');
 155         if (!(e = unit_name_escape_path(sysfs+1, ".device")))
 156                 return -ENOMEM;
 157
 158         if (!(u = manager_get_unit(m, e))) {
 159                 const char *model;
 160
 161                 delete = true;
 162
 163                 if (!(u = unit_new(m))) {
 164                         free(e);
 165                         return -ENOMEM;
 166                 }
 167
 168                 r = unit_add_name(u, e);
 169                 free(e);
 170
 171                 if (r < 0)
 172                         goto fail;
 173
 174                 if (!(DEVICE(u)->sysfs = strdup(sysfs))) {
 175                         r = -ENOMEM;
 176                         goto fail;
 177                 }
 178
 179                 if ((model = udev_device_get_property_value(dev, "ID_MODEL_FROM_DATABASE")) ||
 180                     (model = udev_device_get_property_value(dev, "ID_MODEL"))) {
 181                         if ((r = unit_set_description(u, model)) < 0)
 182                                 goto fail;
 183                 } else if (dn)
 184                         if ((r = unit_set_description(u, dn)) < 0)
 185                                 goto fail;
 186
 187                 unit_add_to_load_queue(u);
 188         } else {
 189                 delete = false;
 190                 free(e);
 191         }
 192
 193         if (dn)
 194                 if ((r = device_add_escaped_name(u, dn, true)) < 0)
 195                         goto fail;
 196
 197         first = udev_device_get_devlinks_list_entry(dev);
 198         udev_list_entry_foreach(item, first)
 199                 if ((r = device_add_escaped_name(u, udev_list_entry_get_name(item), false)) < 0)
 200                         goto fail;
 201
 202         if (names) {
 203                 FOREACH_WORD(w, l, names, state) {
 204                         if (!(e = strndup(w, l))) {
 205                                 r = -ENOMEM;
 206                                 goto fail;
 207                         }
 208
 209                         r = unit_add_name(u, e);
 210                         free(e);
 211
 212                         if (r < 0 && r != -EEXIST)
 213                                 goto fail;
 214                 }
 215         }
 216
 217         if (wants) {
 218                 FOREACH_WORD(w, l, wants, state) {
 219                         if (!(e = strndup(w, l))) {
 220                                 r = -ENOMEM;
 221                                 goto fail;
 222                         }
 223
 224                         r = unit_add_dependency_by_name(u, UNIT_WANTS, e);
 225                         free(e);
 226
 227                         if (r < 0)
 228                                 goto fail;
 229                 }
 230         }
 231
 232         if (update_state) {
 233                 manager_dispatch_load_queue(u->meta.manager);
 234                 device_set_state(DEVICE(u), DEVICE_AVAILABLE);
 235         }
 236
 237         unit_add_to_dbus_queue(u);
 238
 239         return 0;
 240
 241 fail:
 242         if (delete && u)
 243                 unit_free(u);
 244         return r;
 245 }
 246
 247 static int device_process_path(Manager *m, const char *path, bool update_state) {
 248         int r;
 249         struct udev_device *dev;
 250
 251         assert(m);
 252         assert(path);
 253
 254         if (!(dev = udev_device_new_from_syspath(m->udev, path))) {
 255                 log_warning("Failed to get udev device object from udev for path %s.", path);
 256                 return -ENOMEM;
 257         }
 258
 259         r = device_process_new_device(m, dev, update_state);
 260         udev_device_unref(dev);
 261         return r;
 262 }
 263
 264 static int device_process_removed_device(Manager *m, struct udev_device *dev) {
 265         const char *sysfs;
 266         char *e;
 267         Unit *u;
 268         Device *d;
 269
 270         assert(m);
 271         assert(dev);
 272
 273         if (!(sysfs = udev_device_get_syspath(dev)))
 274                 return -ENOMEM;
 275
 276         assert(sysfs[0] == '/');
 277         if (!(e = unit_name_escape_path(sysfs+1, ".device")))
 278                 return -ENOMEM;
 279
 280         u = manager_get_unit(m, e);
 281         free(e);
 282
 283         if (!u)
 284                 return 0;
 285
 286         d = DEVICE(u);
 287         free(d->sysfs);
 288         d->sysfs = NULL;
 289
 290         device_set_state(d, DEVICE_DEAD);
 291         return 0;
 292 }
 293
 294 static void device_shutdown(Manager *m) {
 295         assert(m);
 296
 297         if (m->udev_monitor)
 298                 udev_monitor_unref(m->udev_monitor);
 299
 300         if (m->udev)
 301                 udev_unref(m->udev);
 302 }
 303
 304 static int device_enumerate(Manager *m) {
 305         struct epoll_event ev;
 306         int r;
 307         struct udev_enumerate *e = NULL;
 308         struct udev_list_entry *item = NULL, *first = NULL;
 309
 310         assert(m);
 311
 312         if (!(m->udev = udev_new()))
 313                 return -ENOMEM;
 314
 315         if (!(m->udev_monitor = udev_monitor_new_from_netlink(m->udev, "udev"))) {
 316                 r = -ENOMEM;
 317                 goto fail;
 318         }
 319
 320         if (udev_monitor_enable_receiving(m->udev_monitor) < 0) {
 321                 r = -EIO;
 322                 goto fail;
 323         }
 324
 325         m->udev_watch.type = WATCH_UDEV;
 326         m->udev_watch.fd = udev_monitor_get_fd(m->udev_monitor);
 327
 328         zero(ev);
 329         ev.events = EPOLLIN;
 330         ev.data.ptr = &m->udev_watch;
 331
 332         if (epoll_ctl(m->epoll_fd, EPOLL_CTL_ADD, m->udev_watch.fd, &ev) < 0)
 333                 return -errno;
 334
 335         if (!(e = udev_enumerate_new(m->udev))) {
 336                 r = -ENOMEM;
 337                 goto fail;
 338         }
 339
 340         if (udev_enumerate_scan_devices(e) < 0) {
 341                 r = -EIO;
 342                 goto fail;
 343         }
 344
 345         first = udev_enumerate_get_list_entry(e);
 346         udev_list_entry_foreach(item, first)
 347                 device_process_path(m, udev_list_entry_get_name(item), false);
 348
 349         udev_enumerate_unref(e);
 350         return 0;
 351
 352 fail:
 353         if (e)
 354                 udev_enumerate_unref(e);
 355
 356         device_shutdown(m);
 357         return r;
 358 }
 359
 360 void device_fd_event(Manager *m, int events) {
 361         struct udev_device *dev;
 362         int r;
 363         const char *action;
 364
 365         assert(m);
 366         assert(events == EPOLLIN);
 367
 368         if (!(dev = udev_monitor_receive_device(m->udev_monitor))) {
 369                 log_error("Failed to receive device.");
 370                 return;
 371         }
 372
 373         if (!(action = udev_device_get_action(dev))) {
 374                 log_error("Failed to get udev action string.");
 375                 goto fail;
 376         }
 377
 378         if (streq(action, "remove")) {
 379                 if ((r = device_process_removed_device(m, dev)) < 0) {
 380                         log_error("Failed to process udev device event: %s", strerror(-r));
 381                         goto fail;
 382                 }
 383         } else {
 384                 if ((r = device_process_new_device(m, dev, true)) < 0) {
 385                         log_error("Failed to process udev device event: %s", strerror(-r));
 386                         goto fail;
 387                 }
 388         }
 389
 390 fail:
 391         udev_device_unref(dev);
 392 }
 393
 394 const UnitVTable device_vtable = {
 395         .suffix = ".device",
 396
 397         .init = unit_load_fragment_and_dropin_optional,
 398         .done = device_done,
 399         .coldplug = device_coldplug,
 400
 401         .dump = device_dump,
 402
 403         .active_state = device_active_state,
 404
 405         .enumerate = device_enumerate,
 406         .shutdown = device_shutdown
 407 };