git.ozlabs.org Git - petitboot/blob - discover/udev.c

   1
   2 #if defined(HAVE_CONFIG_H)
   3 #include "config.h"
   4 #endif
   5
   6 #include <assert.h>
   7 #include <errno.h>
   8 #include <libudev.h>
   9 #include <stdio.h>
  10 #include <stdlib.h>
  11 #include <string.h>
  12 #include <unistd.h>
  13 #include <sys/socket.h>
  14 #include <sys/types.h>
  15 #include <sys/un.h>
  16
  17 #include <log/log.h>
  18 #include <types/types.h>
  19 #include <talloc/talloc.h>
  20 #include <waiter/waiter.h>
  21 #include <system/system.h>
  22
  23 #include "event.h"
  24 #include "udev.h"
  25 #include "pb-discover.h"
  26 #include "device-handler.h"
  27 #include "cdrom.h"
  28
  29 /* We set a default monitor buffer size, as we may not process monitor
  30  * events while performing device discvoery. systemd uses a 128M buffer, so
  31  * we'll do the same here */
  32 static const int monitor_bufsize = 128 * 1024 * 1024;
  33
  34 struct pb_udev {
  35         struct udev *udev;
  36         struct udev_monitor *monitor;
  37         struct device_handler *handler;
  38 };
  39
  40 static int udev_destructor(void *p)
  41 {
  42         struct pb_udev *udev = p;
  43
  44         udev_monitor_unref(udev->monitor);
  45         udev->monitor = NULL;
  46
  47         udev_unref(udev->udev);
  48         udev->udev = NULL;
  49
  50         return 0;
  51 }
  52
  53 static void udev_setup_device_params(struct udev_device *udev,
  54                 struct discover_device *dev)
  55 {
  56         struct udev_list_entry *list, *entry;
  57
  58         list = udev_device_get_properties_list_entry(udev);
  59         if (!list)
  60                 return;
  61
  62         udev_list_entry_foreach(entry, list)
  63                 discover_device_set_param(dev,
  64                                 udev_list_entry_get_name(entry),
  65                                 udev_list_entry_get_value(entry));
  66 }
  67
  68 static int udev_handle_block_add(struct pb_udev *udev, struct udev_device *dev,
  69                 const char *name)
  70 {
  71         struct discover_device *ddev;
  72         const char *typestr;
  73         const char *uuid;
  74         const char *path;
  75         const char *node;
  76         const char *prop;
  77         const char *type;
  78         bool cdrom;
  79
  80         typestr = udev_device_get_devtype(dev);
  81         if (!typestr) {
  82                 pb_debug("udev_device_get_devtype failed\n");
  83                 return -1;
  84         }
  85
  86         if (!(!strcmp(typestr, "disk") || !strcmp(typestr, "partition"))) {
  87                 pb_log("SKIP %s: invalid type %s\n", name, typestr);
  88                 return 0;
  89         }
  90
  91         node = udev_device_get_devnode(dev);
  92         path = udev_device_get_devpath(dev);
  93         if (path && (strstr(path, "virtual/block/loop")
  94                         || strstr(path, "virtual/block/ram"))) {
  95                 pb_log("SKIP: %s: ignored (path=%s)\n", name, path);
  96                 return 0;
  97         }
  98
  99         cdrom = node && !!udev_device_get_property_value(dev, "ID_CDROM");
 100         if (cdrom) {
 101                 /* CDROMs require a little initialisation, to get
 102                  * petitboot-compatible tray behaviour */
 103                 cdrom_init(node);
 104                 if (!cdrom_media_present(node)) {
 105                         pb_log("SKIP: %s: no media present\n", name);
 106                         return 0;
 107                 }
 108         }
 109
 110         type = udev_device_get_property_value(dev, "ID_FS_TYPE");
 111         if (!type) {
 112                 pb_log("SKIP: %s: no ID_FS_TYPE property\n", name);
 113                 return 0;
 114         }
 115
 116         /* We may see multipath devices; they'll have the same uuid as an
 117          * existing device, so only parse the first. */
 118         uuid = udev_device_get_property_value(dev, "ID_FS_UUID");
 119         if (uuid) {
 120                 ddev = device_lookup_by_uuid(udev->handler, uuid);
 121                 if (ddev) {
 122                         pb_log("SKIP: %s UUID [%s] already present (as %s)\n",
 123                                         name, uuid, ddev->device->id);
 124                         return 0;
 125                 }
 126         }
 127
 128         ddev = discover_device_create(udev->handler, name);
 129
 130         ddev->device_path = talloc_strdup(ddev, node);
 131
 132         if (uuid)
 133                 ddev->uuid = talloc_strdup(ddev, uuid);
 134         prop = udev_device_get_property_value(dev, "ID_FS_LABEL");
 135         if (prop)
 136                 ddev->label = talloc_strdup(ddev, prop);
 137         ddev->device->type = cdrom ? DEVICE_TYPE_OPTICAL : DEVICE_TYPE_DISK;
 138
 139         udev_setup_device_params(dev, ddev);
 140
 141         device_handler_discover(udev->handler, ddev);
 142
 143         return 0;
 144 }
 145
 146 static int udev_handle_dev_add(struct pb_udev *udev, struct udev_device *dev)
 147 {
 148         const char *subsys;
 149         const char *name;
 150
 151         name = udev_device_get_sysname(dev);
 152         if (!name) {
 153                 pb_debug("udev_device_get_sysname failed\n");
 154                 return -1;
 155         }
 156
 157         subsys = udev_device_get_subsystem(dev);
 158         if (!subsys) {
 159                 pb_debug("udev_device_get_subsystem failed\n");
 160                 return -1;
 161         }
 162
 163         if (device_lookup_by_id(udev->handler, name)) {
 164                 pb_debug("device %s is already present?\n", name);
 165                 return -1;
 166         }
 167
 168         if (!strcmp(subsys, "block")) {
 169                 return udev_handle_block_add(udev, dev, name);
 170         }
 171
 172         pb_log("SKIP %s: unknown subsystem %s\n", name, subsys);
 173         return -1;
 174 }
 175
 176
 177 static int udev_handle_dev_remove(struct pb_udev *udev, struct udev_device *dev)
 178 {
 179         struct discover_device *ddev;
 180         const char *name;
 181
 182         name = udev_device_get_sysname(dev);
 183         if (!name) {
 184                 pb_debug("udev_device_get_sysname failed\n");
 185                 return -1;
 186         }
 187
 188         ddev = device_lookup_by_id(udev->handler, name);
 189         if (!ddev)
 190                 return 0;
 191
 192         device_handler_remove(udev->handler, ddev);
 193
 194         return 0;
 195 }
 196
 197 /* returns true if further event processing should stop (eg., we've
 198  * ejected the cdrom)
 199  */
 200 static bool udev_handle_cdrom_events(struct pb_udev *udev,
 201                 struct udev_device *dev, struct discover_device *ddev)
 202 {
 203         const char *node;
 204
 205         node = udev_device_get_devnode(dev);
 206
 207         /* handle CDROM eject requests */
 208         if (udev_device_get_property_value(dev, "DISK_EJECT_REQUEST")) {
 209                 bool eject = false;
 210
 211                 pb_debug("udev: eject request\n");
 212
 213                 /* If the device is mounted, cdrom_id's own eject request may
 214                  * have failed. So, we'll need to do our own here.
 215                  */
 216                 if (ddev) {
 217                         eject = ddev->mounted;
 218                         udev_handle_dev_remove(udev, dev);
 219                         return false;
 220                 }
 221
 222                 if (eject)
 223                         cdrom_eject(node);
 224
 225                 return true;
 226         }
 227
 228         if (udev_device_get_property_value(dev, "DISK_MEDIA_CHANGE")) {
 229                 if (cdrom_media_present(node))
 230                         udev_handle_dev_add(udev, dev);
 231                 else
 232                         udev_handle_dev_remove(udev, dev);
 233                 return true;
 234         }
 235
 236         return false;
 237 }
 238
 239 static int udev_handle_dev_change(struct pb_udev *udev, struct udev_device *dev)
 240 {
 241         struct discover_device *ddev;
 242         const char *name;
 243         int rc = 0;
 244
 245         name = udev_device_get_sysname(dev);
 246
 247         ddev = device_lookup_by_id(udev->handler, name);
 248
 249         /* if this is a CDROM device, process eject & media change requests;
 250          * these may stop further processing */
 251         if (!udev_device_get_property_value(dev, "ID_CDROM")) {
 252                 if (udev_handle_cdrom_events(udev, dev, ddev))
 253                         return 0;
 254         }
 255
 256         /* if this is a new device, treat it as an add */
 257         if (!ddev)
 258                 rc = udev_handle_dev_add(udev, dev);
 259
 260         return rc;
 261 }
 262
 263 static int udev_handle_dev_action(struct udev_device *dev, const char *action)
 264 {
 265         struct pb_udev *udev = udev_get_userdata(udev_device_get_udev(dev));
 266
 267 #ifdef DEBUG
 268         {
 269                 struct udev_list_entry *list;
 270                 const char *name;
 271
 272                 list = udev_device_get_properties_list_entry(dev);
 273                 name = udev_device_get_sysname(dev);
 274
 275                 pb_debug("%s: action %s, device %s\n", __func__, action, name);
 276                 pb_debug("%s properties:\n", __func__);
 277
 278                 for (; list; list = udev_list_entry_get_next(list))
 279                         pb_log("\t%-20s: %s\n", udev_list_entry_get_name(list),
 280                                         udev_list_entry_get_value(list));
 281         } while (0);
 282 #endif
 283
 284         if (!strcmp(action, "add"))
 285                 return udev_handle_dev_add(udev, dev);
 286
 287         else if (!strcmp(action, "remove"))
 288                 return udev_handle_dev_remove(udev, dev);
 289
 290         else if (!strcmp(action, "change"))
 291                 return udev_handle_dev_change(udev, dev);
 292
 293         return 0;
 294 }
 295
 296 static int udev_enumerate(struct udev *udev)
 297 {
 298         int result;
 299         struct udev_list_entry *list, *entry;
 300         struct udev_enumerate *enumerate;
 301
 302         enumerate = udev_enumerate_new(udev);
 303
 304         if (!enumerate) {
 305                 pb_log("udev_enumerate_new failed\n");
 306                 return -1;
 307         }
 308
 309         result = udev_enumerate_add_match_subsystem(enumerate, "block");
 310         if (result) {
 311                 pb_log("udev_enumerate_add_match_subsystem failed\n");
 312                 goto fail;
 313         }
 314
 315         result = udev_enumerate_add_match_is_initialized(enumerate);
 316         if (result) {
 317                 pb_log("udev_enumerate_add_match_is_initialised failed\n");
 318                 goto fail;
 319         }
 320
 321         udev_enumerate_scan_devices(enumerate);
 322
 323         list = udev_enumerate_get_list_entry(enumerate);
 324
 325         if (!list) {
 326                 pb_log("udev_enumerate_get_list_entry failed\n");
 327                 goto fail;
 328         }
 329
 330         udev_list_entry_foreach(entry, list) {
 331                 const char *syspath;
 332                 struct udev_device *dev;
 333
 334                 syspath = udev_list_entry_get_name(entry);
 335                 dev = udev_device_new_from_syspath(udev, syspath);
 336
 337                 udev_handle_dev_action(dev, "add");
 338
 339                 udev_device_unref(dev);
 340         }
 341
 342         udev_enumerate_unref(enumerate);
 343         return 0;
 344
 345 fail:
 346         udev_enumerate_unref(enumerate);
 347         return -1;
 348 }
 349
 350 static int udev_setup_monitor(struct udev *udev, struct udev_monitor **monitor)
 351 {
 352         int result;
 353         struct udev_monitor *m;
 354
 355         *monitor = NULL;
 356         m = udev_monitor_new_from_netlink(udev, "udev");
 357
 358         if (!m) {
 359                 pb_log("udev_monitor_new_from_netlink failed\n");
 360                 goto out_err;
 361         }
 362
 363         result = udev_monitor_set_receive_buffer_size(m, monitor_bufsize);
 364         if (result) {
 365                 pb_log("udev_monitor_set_rx_bufsize(%d) failed\n",
 366                         monitor_bufsize);
 367         }
 368
 369         result = udev_monitor_filter_add_match_subsystem_devtype(m, "block",
 370                 NULL);
 371
 372         if (result) {
 373                 pb_log("udev_monitor_filter_add_match_subsystem_devtype failed\n");
 374                 goto out_err;
 375         }
 376
 377         result = udev_monitor_enable_receiving(m);
 378
 379         if (result) {
 380                 pb_log("udev_monitor_enable_receiving failed\n");
 381                 goto out_err;
 382         }
 383
 384         *monitor = m;
 385         return 0;
 386
 387 out_err:
 388         udev_monitor_unref(m);
 389         return -1;
 390 }
 391
 392 /*
 393  * udev_process - waiter callback for monitor netlink.
 394  */
 395
 396 static int udev_process(void *arg)
 397 {
 398         struct udev_monitor *monitor = arg;
 399         struct udev_device *dev;
 400         const char *action;
 401
 402         dev = udev_monitor_receive_device(monitor);
 403         if (!dev) {
 404                 pb_log("udev_monitor_receive_device failed\n");
 405                 return -1;
 406         }
 407
 408         action = udev_device_get_action(dev);
 409
 410         if (!action) {
 411                 pb_log("udev_device_get_action failed\n");
 412         } else {
 413                 udev_handle_dev_action(dev, action);
 414         }
 415
 416         udev_device_unref(dev);
 417         return 0;
 418 }
 419
 420 static void udev_log_fn(struct udev __attribute__((unused)) *udev,
 421         int __attribute__((unused)) priority, const char *file, int line,
 422         const char *fn, const char *format, va_list args)
 423 {
 424       pb_log("libudev: %s %s:%d: ", fn, file, line);
 425       vfprintf(pb_log_get_stream(), format, args);
 426 }
 427
 428 struct pb_udev *udev_init(struct device_handler *handler,
 429                 struct waitset *waitset)
 430 {
 431         struct pb_udev *udev;
 432         int result;
 433
 434         udev = talloc(handler, struct pb_udev);
 435         talloc_set_destructor(udev, udev_destructor);
 436         udev->handler = handler;
 437
 438         udev->udev = udev_new();
 439
 440         if (!udev->udev) {
 441                 pb_log("udev_new failed\n");
 442                 goto fail_new;
 443         }
 444
 445         udev_set_userdata(udev->udev, udev);
 446
 447         udev_set_log_fn(udev->udev, udev_log_fn);
 448
 449         result = udev_setup_monitor(udev->udev, &udev->monitor);
 450         if (result)
 451                 goto fail_monitor;
 452
 453         result = udev_enumerate(udev->udev);
 454         if (result)
 455                 goto fail_enumerate;
 456
 457         waiter_register_io(waitset, udev_monitor_get_fd(udev->monitor), WAIT_IN,
 458                 udev_process, udev->monitor);
 459
 460         pb_debug("%s: waiting on udev\n", __func__);
 461
 462         return udev;
 463
 464 fail_monitor:
 465         udev_monitor_unref(udev->monitor);
 466 fail_enumerate:
 467         udev_unref(udev->udev);
 468 fail_new:
 469         talloc_free(udev);
 470         return NULL;
 471 }
 472
 473 void udev_reinit(struct pb_udev *udev)
 474 {
 475         pb_log("udev: reinit requested, starting enumeration\n");
 476         udev_enumerate(udev->udev);
 477 }