device.c

   1 /*-*- Mode: C; c-basic-offset: 8 -*-*/
   2
   3 #include <errno.h>
   4 #include <sys/epoll.h>
   5 #include <libudev.h>
   6
   7 #include "unit.h"
   8 #include "device.h"
   9 #include "strv.h"
  10 #include "log.h"
  11
  12 static const UnitActiveState state_translation_table[_DEVICE_STATE_MAX] = {
  13         [DEVICE_DEAD] = UNIT_INACTIVE,
  14         [DEVICE_AVAILABLE] = UNIT_ACTIVE
  15 };
  16
  17 static const char* const state_string_table[_DEVICE_STATE_MAX] = {
  18         [DEVICE_DEAD] = "dead",
  19         [DEVICE_AVAILABLE] = "available"
  20 };
  21
  22 static void device_done(Unit *u) {
  23         Device *d = DEVICE(u);
  24
  25         assert(d);
  26         free(d->sysfs);
  27 }
  28
  29 static void device_set_state(Device *d, DeviceState state) {
  30         DeviceState old_state;
  31         assert(d);
  32
  33         old_state = d->state;
  34         d->state = state;
  35
  36         log_debug("%s changed %s → %s", unit_id(UNIT(d)), state_string_table[old_state], state_string_table[state]);
  37
  38         unit_notify(UNIT(d), state_translation_table[old_state], state_translation_table[state]);
  39 }
  40
  41 static int device_coldplug(Unit *u) {
  42         Device *d = DEVICE(u);
  43
  44         assert(d);
  45         assert(d->state == DEVICE_DEAD);
  46
  47         if (d->sysfs)
  48                 device_set_state(d, DEVICE_AVAILABLE);
  49
  50         return 0;
  51 }
  52
  53 static void device_dump(Unit *u, FILE *f, const char *prefix) {
  54         Device *d = DEVICE(u);
  55
  56         assert(d);
  57
  58         fprintf(f,
  59                 "%sDevice State: %s\n"
  60                 "%sSysfs Path: %s\n",
  61                 prefix, state_string_table[d->state],
  62                 prefix, strna(d->sysfs));
  63 }
  64
  65 static UnitActiveState device_active_state(Unit *u) {
  66         assert(u);
  67
  68         return state_translation_table[DEVICE(u)->state];
  69 }
  70
  71 static int device_add_escaped_name(Unit *u, const char *prefix, const char *dn, bool make_id) {
  72         char *e;
  73         int r;
  74
  75         assert(u);
  76         assert(dn);
  77         assert(dn[0] == '/');
  78
  79         if (!(e = unit_name_escape_path(prefix, dn+1, ".device")))
  80                 return -ENOMEM;
  81
  82         r = unit_add_name(u, e);
  83
  84         if (r >= 0 && make_id)
  85                 unit_choose_id(u, e);
  86
  87         free(e);
  88
  89         if (r < 0 && r != -EEXIST)
  90                 return r;
  91
  92         return 0;
  93 }
  94
  95 static int device_process_new_device(Manager *m, struct udev_device *dev, bool update_state) {
  96         const char *dn, *names, *wants, *sysfs;
  97         Unit *u = NULL;
  98         int r;
  99         char *e, *w, *state;
 100         size_t l;
 101         bool delete;
 102         struct udev_list_entry *item = NULL, *first = NULL;
 103
 104         assert(m);
 105
 106         /* Check whether this entry is even relevant for us. */
 107         dn = udev_device_get_devnode(dev);
 108         names = udev_device_get_property_value(dev, "SYSTEMD_NAMES");
 109         wants = udev_device_get_property_value(dev, "SYSTEMD_WANTS");
 110
 111         if (!dn && !names && !wants)
 112                 return 0;
 113
 114         /* Ok, seems kinda interesting. Now, let's see if this one
 115          * already exists. */
 116
 117         if (!(sysfs = udev_device_get_syspath(dev)))
 118                 return -ENOMEM;
 119
 120         assert(sysfs[0] == '/');
 121         if (!(e = unit_name_escape_path("sysfs-", sysfs+1, ".device")))
 122                 return -ENOMEM;
 123
 124         if (!(u = manager_get_unit(m, e))) {
 125                 const char *model;
 126
 127                 delete = true;
 128
 129                 if (!(u = unit_new(m))) {
 130                         free(e);
 131                         return -ENOMEM;
 132                 }
 133
 134                 r = unit_add_name(u, e);
 135                 free(e);
 136
 137                 if (r < 0)
 138                         goto fail;
 139
 140                 if (!(DEVICE(u)->sysfs = strdup(sysfs))) {
 141                         r = -ENOMEM;
 142                         goto fail;
 143                 }
 144
 145                 if ((model = udev_device_get_property_value(dev, "ID_MODEL_FROM_DATABASE")) ||
 146                     (model = udev_device_get_property_value(dev, "ID_MODEL")))
 147                         if ((r = unit_set_description(u, model)) < 0)
 148                                 goto fail;
 149
 150                 unit_add_to_load_queue(u);
 151         } else {
 152                 delete = false;
 153                 free(e);
 154         }
 155
 156         if (dn)
 157                 if ((r = device_add_escaped_name(u, "node-", dn, true)) < 0)
 158                         goto fail;
 159
 160         first = udev_device_get_devlinks_list_entry(dev);
 161         udev_list_entry_foreach(item, first)
 162                 if ((r = device_add_escaped_name(u, "node-", udev_list_entry_get_name(item), false)) < 0)
 163                         goto fail;
 164
 165         if (names) {
 166                 FOREACH_WORD(w, l, names, state) {
 167                         if (!(e = strndup(w, l)))
 168                                 goto fail;
 169
 170                         r = unit_add_name(u, e);
 171                         free(e);
 172
 173                         if (r < 0 && r != -EEXIST)
 174                                 goto fail;
 175                 }
 176         }
 177
 178         if (wants) {
 179                 FOREACH_WORD(w, l, wants, state) {
 180                         if (!(e = strndup(w, l)))
 181                                 goto fail;
 182
 183                         r = unit_add_dependency_by_name(u, UNIT_WANTS, e);
 184                         free(e);
 185
 186                         if (r < 0)
 187                                 goto fail;
 188                 }
 189         }
 190
 191         if (update_state) {
 192                 manager_dispatch_load_queue(u->meta.manager);
 193                 device_set_state(DEVICE(u), DEVICE_AVAILABLE);
 194         }
 195
 196         return 0;
 197
 198 fail:
 199         if (delete && u)
 200                 unit_free(u);
 201         return r;
 202 }
 203
 204 static int device_process_path(Manager *m, const char *path, bool update_state) {
 205         int r;
 206         struct udev_device *dev;
 207
 208         assert(m);
 209         assert(path);
 210
 211         if (!(dev = udev_device_new_from_syspath(m->udev, path))) {
 212                 log_warning("Failed to get udev device object from udev for path %s.", path);
 213                 return -ENOMEM;
 214         }
 215
 216         r = device_process_new_device(m, dev, update_state);
 217         udev_device_unref(dev);
 218         return r;
 219 }
 220
 221 static int device_process_removed_device(Manager *m, struct udev_device *dev) {
 222         const char *sysfs;
 223         char *e;
 224         Unit *u;
 225         Device *d;
 226
 227         assert(m);
 228         assert(dev);
 229
 230         if (!(sysfs = udev_device_get_syspath(dev)))
 231                 return -ENOMEM;
 232
 233         assert(sysfs[0] == '/');
 234         if (!(e = unit_name_escape_path("sysfs-", sysfs+1, ".device")))
 235                 return -ENOMEM;
 236
 237         u = manager_get_unit(m, e);
 238         free(e);
 239
 240         if (!u)
 241                 return 0;
 242
 243         d = DEVICE(u);
 244         free(d->sysfs);
 245         d->sysfs = NULL;
 246
 247         device_set_state(d, DEVICE_DEAD);
 248         return 0;
 249 }
 250
 251 static void device_shutdown(Manager *m) {
 252         assert(m);
 253
 254         if (m->udev_monitor)
 255                 udev_monitor_unref(m->udev_monitor);
 256
 257         if (m->udev)
 258                 udev_unref(m->udev);
 259 }
 260
 261 static int device_enumerate(Manager *m) {
 262         struct epoll_event ev;
 263         int r;
 264         struct udev_enumerate *e = NULL;
 265         struct udev_list_entry *item = NULL, *first = NULL;
 266
 267         assert(m);
 268
 269         if (!(m->udev = udev_new()))
 270                 return -ENOMEM;
 271
 272         if (!(m->udev_monitor = udev_monitor_new_from_netlink(m->udev, "udev"))) {
 273                 r = -ENOMEM;
 274                 goto fail;
 275         }
 276
 277         if (udev_monitor_enable_receiving(m->udev_monitor) < 0) {
 278                 r = -EIO;
 279                 goto fail;
 280         }
 281
 282         m->udev_watch.type = WATCH_UDEV;
 283         m->udev_watch.fd = udev_monitor_get_fd(m->udev_monitor);
 284
 285         zero(ev);
 286         ev.events = EPOLLIN;
 287         ev.data.ptr = &m->udev_watch;
 288
 289         if (epoll_ctl(m->epoll_fd, EPOLL_CTL_ADD, m->udev_watch.fd, &ev) < 0)
 290                 return -errno;
 291
 292         if (!(e = udev_enumerate_new(m->udev))) {
 293                 r = -ENOMEM;
 294                 goto fail;
 295         }
 296
 297         if (udev_enumerate_scan_devices(e) < 0) {
 298                 r = -EIO;
 299                 goto fail;
 300         }
 301
 302         first = udev_enumerate_get_list_entry(e);
 303         udev_list_entry_foreach(item, first)
 304                 device_process_path(m, udev_list_entry_get_name(item), false);
 305
 306         udev_enumerate_unref(e);
 307         return 0;
 308
 309 fail:
 310         if (e)
 311                 udev_enumerate_unref(e);
 312
 313         device_shutdown(m);
 314         return r;
 315 }
 316
 317 void device_fd_event(Manager *m, int events) {
 318         struct udev_device *dev;
 319         int r;
 320         const char *action;
 321
 322         assert(m);
 323         assert(events == EPOLLIN);
 324
 325         log_debug("got udev event");
 326
 327         if (!(dev = udev_monitor_receive_device(m->udev_monitor))) {
 328                 log_error("Failed to receive device.");
 329                 return;
 330         }
 331
 332         if (!(action = udev_device_get_action(dev))) {
 333                 log_error("Failed to get udev action string.");
 334                 goto fail;
 335         }
 336
 337         if (streq(action, "remove")) {
 338                 if ((r = device_process_removed_device(m, dev)) < 0) {
 339                         log_error("Failed to process udev device event: %s", strerror(-r));
 340                         goto fail;
 341                 }
 342         } else {
 343                 if ((r = device_process_new_device(m, dev, true)) < 0) {
 344                         log_error("Failed to process udev device event: %s", strerror(-r));
 345                         goto fail;
 346                 }
 347         }
 348
 349 fail:
 350         udev_device_unref(dev);
 351 }
 352
 353 const UnitVTable device_vtable = {
 354         .suffix = ".device",
 355
 356         .init = unit_load_fragment_and_dropin,
 357         .done = device_done,
 358         .coldplug = device_coldplug,
 359
 360         .dump = device_dump,
 361
 362         .active_state = device_active_state,
 363
 364         .enumerate = device_enumerate,
 365         .shutdown = device_shutdown
 366 };