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 *prefix, 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(prefix, 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-", 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
 169                 unit_add_to_load_queue(u);
 170         } else {
 171                 delete = false;
 172                 free(e);
 173         }
 174
 175         if (dn)
 176                 if ((r = device_add_escaped_name(u, "node-", dn, true)) < 0)
 177                         goto fail;
 178
 179         first = udev_device_get_devlinks_list_entry(dev);
 180         udev_list_entry_foreach(item, first)
 181                 if ((r = device_add_escaped_name(u, "node-", udev_list_entry_get_name(item), false)) < 0)
 182                         goto fail;
 183
 184         if (names) {
 185                 FOREACH_WORD(w, l, names, state) {
 186                         if (!(e = strndup(w, l)))
 187                                 goto fail;
 188
 189                         r = unit_add_name(u, e);
 190                         free(e);
 191
 192                         if (r < 0 && r != -EEXIST)
 193                                 goto fail;
 194                 }
 195         }
 196
 197         if (wants) {
 198                 FOREACH_WORD(w, l, wants, state) {
 199                         if (!(e = strndup(w, l)))
 200                                 goto fail;
 201
 202                         r = unit_add_dependency_by_name(u, UNIT_WANTS, e);
 203                         free(e);
 204
 205                         if (r < 0)
 206                                 goto fail;
 207                 }
 208         }
 209
 210         if (update_state) {
 211                 manager_dispatch_load_queue(u->meta.manager);
 212                 device_set_state(DEVICE(u), DEVICE_AVAILABLE);
 213         }
 214
 215         return 0;
 216
 217 fail:
 218         if (delete && u)
 219                 unit_free(u);
 220         return r;
 221 }
 222
 223 static int device_process_path(Manager *m, const char *path, bool update_state) {
 224         int r;
 225         struct udev_device *dev;
 226
 227         assert(m);
 228         assert(path);
 229
 230         if (!(dev = udev_device_new_from_syspath(m->udev, path))) {
 231                 log_warning("Failed to get udev device object from udev for path %s.", path);
 232                 return -ENOMEM;
 233         }
 234
 235         r = device_process_new_device(m, dev, update_state);
 236         udev_device_unref(dev);
 237         return r;
 238 }
 239
 240 static int device_process_removed_device(Manager *m, struct udev_device *dev) {
 241         const char *sysfs;
 242         char *e;
 243         Unit *u;
 244         Device *d;
 245
 246         assert(m);
 247         assert(dev);
 248
 249         if (!(sysfs = udev_device_get_syspath(dev)))
 250                 return -ENOMEM;
 251
 252         assert(sysfs[0] == '/');
 253         if (!(e = unit_name_escape_path("sysfs-", sysfs+1, ".device")))
 254                 return -ENOMEM;
 255
 256         u = manager_get_unit(m, e);
 257         free(e);
 258
 259         if (!u)
 260                 return 0;
 261
 262         d = DEVICE(u);
 263         free(d->sysfs);
 264         d->sysfs = NULL;
 265
 266         device_set_state(d, DEVICE_DEAD);
 267         return 0;
 268 }
 269
 270 static void device_shutdown(Manager *m) {
 271         assert(m);
 272
 273         if (m->udev_monitor)
 274                 udev_monitor_unref(m->udev_monitor);
 275
 276         if (m->udev)
 277                 udev_unref(m->udev);
 278 }
 279
 280 static int device_enumerate(Manager *m) {
 281         struct epoll_event ev;
 282         int r;
 283         struct udev_enumerate *e = NULL;
 284         struct udev_list_entry *item = NULL, *first = NULL;
 285
 286         assert(m);
 287
 288         if (!(m->udev = udev_new()))
 289                 return -ENOMEM;
 290
 291         if (!(m->udev_monitor = udev_monitor_new_from_netlink(m->udev, "udev"))) {
 292                 r = -ENOMEM;
 293                 goto fail;
 294         }
 295
 296         if (udev_monitor_enable_receiving(m->udev_monitor) < 0) {
 297                 r = -EIO;
 298                 goto fail;
 299         }
 300
 301         m->udev_watch.type = WATCH_UDEV;
 302         m->udev_watch.fd = udev_monitor_get_fd(m->udev_monitor);
 303
 304         zero(ev);
 305         ev.events = EPOLLIN;
 306         ev.data.ptr = &m->udev_watch;
 307
 308         if (epoll_ctl(m->epoll_fd, EPOLL_CTL_ADD, m->udev_watch.fd, &ev) < 0)
 309                 return -errno;
 310
 311         if (!(e = udev_enumerate_new(m->udev))) {
 312                 r = -ENOMEM;
 313                 goto fail;
 314         }
 315
 316         if (udev_enumerate_scan_devices(e) < 0) {
 317                 r = -EIO;
 318                 goto fail;
 319         }
 320
 321         first = udev_enumerate_get_list_entry(e);
 322         udev_list_entry_foreach(item, first)
 323                 device_process_path(m, udev_list_entry_get_name(item), false);
 324
 325         udev_enumerate_unref(e);
 326         return 0;
 327
 328 fail:
 329         if (e)
 330                 udev_enumerate_unref(e);
 331
 332         device_shutdown(m);
 333         return r;
 334 }
 335
 336 void device_fd_event(Manager *m, int events) {
 337         struct udev_device *dev;
 338         int r;
 339         const char *action;
 340
 341         assert(m);
 342         assert(events == EPOLLIN);
 343
 344         log_debug("got udev event");
 345
 346         if (!(dev = udev_monitor_receive_device(m->udev_monitor))) {
 347                 log_error("Failed to receive device.");
 348                 return;
 349         }
 350
 351         if (!(action = udev_device_get_action(dev))) {
 352                 log_error("Failed to get udev action string.");
 353                 goto fail;
 354         }
 355
 356         if (streq(action, "remove")) {
 357                 if ((r = device_process_removed_device(m, dev)) < 0) {
 358                         log_error("Failed to process udev device event: %s", strerror(-r));
 359                         goto fail;
 360                 }
 361         } else {
 362                 if ((r = device_process_new_device(m, dev, true)) < 0) {
 363                         log_error("Failed to process udev device event: %s", strerror(-r));
 364                         goto fail;
 365                 }
 366         }
 367
 368 fail:
 369         udev_device_unref(dev);
 370 }
 371
 372 const UnitVTable device_vtable = {
 373         .suffix = ".device",
 374
 375         .init = unit_load_fragment_and_dropin,
 376         .done = device_done,
 377         .coldplug = device_coldplug,
 378
 379         .dump = device_dump,
 380
 381         .active_state = device_active_state,
 382
 383         .enumerate = device_enumerate,
 384         .shutdown = device_shutdown
 385 };