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 #include "devmapper.h"
  29
  30 /* We set a default monitor buffer size, as we may not process monitor
  31  * events while performing device discvoery. systemd uses a 128M buffer, so
  32  * we'll do the same here */
  33 static const int monitor_bufsize = 128 * 1024 * 1024;
  34
  35 struct pb_udev {
  36         struct udev *udev;
  37         struct udev_monitor *monitor;
  38         struct device_handler *handler;
  39 };
  40
  41 static int udev_destructor(void *p)
  42 {
  43         struct pb_udev *udev = p;
  44
  45         if (udev->monitor) {
  46                 udev_monitor_unref(udev->monitor);
  47                 udev->monitor = NULL;
  48         }
  49
  50         if (udev->udev) {
  51                 udev_unref(udev->udev);
  52                 udev->udev = NULL;
  53         }
  54
  55         return 0;
  56 }
  57
  58 static void udev_setup_device_params(struct udev_device *udev,
  59                 struct discover_device *dev)
  60 {
  61         struct udev_list_entry *list, *entry;
  62
  63         list = udev_device_get_properties_list_entry(udev);
  64         if (!list)
  65                 return;
  66
  67         udev_list_entry_foreach(entry, list)
  68                 discover_device_set_param(dev,
  69                                 udev_list_entry_get_name(entry),
  70                                 udev_list_entry_get_value(entry));
  71 }
  72
  73 static int udev_handle_block_add(struct pb_udev *udev, struct udev_device *dev,
  74                 const char *name)
  75 {
  76         struct discover_device *ddev;
  77         unsigned int i = 0;
  78         const char *typestr;
  79         const char *uuid;
  80         const char *path;
  81         const char *node;
  82         const char *prop;
  83         const char *type;
  84         const char *devname;
  85         const char *ignored_types[] = {
  86                 "linux_raid_member",
  87                 "swap",
  88                 "LVM2_member",
  89                 NULL,
  90         };
  91         bool cdrom, usb;
  92
  93         typestr = udev_device_get_devtype(dev);
  94         if (!typestr) {
  95                 pb_debug("udev_device_get_devtype failed\n");
  96                 return -1;
  97         }
  98
  99         if (!(!strcmp(typestr, "disk") || !strcmp(typestr, "partition"))) {
 100                 pb_log("SKIP %s: invalid type %s\n", name, typestr);
 101                 return 0;
 102         }
 103
 104         node = udev_device_get_devnode(dev);
 105         path = udev_device_get_devpath(dev);
 106         if (path && strstr(path, "virtual/block/loop")) {
 107                 pb_log("SKIP: %s: ignored (path=%s)\n", name, path);
 108                 return 0;
 109         }
 110
 111         if (path && strstr(path, "virtual/block/ram")) {
 112                 device_handler_add_ramdisk(udev->handler, node);
 113                 return 0;
 114         }
 115
 116         cdrom = node && !!udev_device_get_property_value(dev, "ID_CDROM");
 117         if (cdrom) {
 118                 /* CDROMs require a little initialisation, to get
 119                  * petitboot-compatible tray behaviour */
 120                 cdrom_init(node);
 121                 if (!cdrom_media_present(node)) {
 122                         pb_log("SKIP: %s: no media present\n", name);
 123                         return 0;
 124                 }
 125         }
 126
 127         /* If our environment's udev can recognise them explictly skip any
 128          * device mapper devices we encounter */
 129         devname = udev_device_get_property_value(dev, "DM_NAME");
 130         if (devname) {
 131                 pb_debug("SKIP: dm-device %s\n", devname);
 132                 return 0;
 133         }
 134
 135         type = udev_device_get_property_value(dev, "ID_FS_TYPE");
 136         if (!type) {
 137                 pb_log("SKIP: %s: no ID_FS_TYPE property\n", name);
 138                 return 0;
 139         }
 140
 141         while (ignored_types[i]) {
 142                 if (!strncmp(type, ignored_types[i], strlen(ignored_types[i]))) {
 143                         pb_log("SKIP: %s: ignore '%s' filesystem\n", name, type);
 144                         return 0;
 145                 }
 146                 i++;
 147         }
 148
 149         /* We may see multipath devices; they'll have the same uuid as an
 150          * existing device, so only parse the first. */
 151         uuid = udev_device_get_property_value(dev, "ID_FS_UUID");
 152         if (uuid) {
 153                 ddev = device_lookup_by_uuid(udev->handler, uuid);
 154                 if (ddev) {
 155                         pb_log("SKIP: %s UUID [%s] already present (as %s)\n",
 156                                         name, uuid, ddev->device->id);
 157                         return 0;
 158                 }
 159         }
 160
 161         ddev = discover_device_create(udev->handler, name);
 162
 163         ddev->device_path = talloc_strdup(ddev, node);
 164
 165         if (uuid)
 166                 ddev->uuid = talloc_strdup(ddev, uuid);
 167         prop = udev_device_get_property_value(dev, "ID_FS_LABEL");
 168         if (prop)
 169                 ddev->label = talloc_strdup(ddev, prop);
 170
 171         usb = !!udev_device_get_property_value(dev, "ID_USB_DRIVER");
 172         if (cdrom)
 173                 ddev->device->type = DEVICE_TYPE_OPTICAL;
 174         else
 175                 ddev->device->type = usb ? DEVICE_TYPE_USB : DEVICE_TYPE_DISK;
 176
 177         udev_setup_device_params(dev, ddev);
 178
 179         /* Create a snapshot for all disk devices */
 180         if ((ddev->device->type == DEVICE_TYPE_DISK ||
 181              ddev->device->type == DEVICE_TYPE_USB))
 182                 devmapper_init_snapshot(udev->handler, ddev);
 183
 184         device_handler_discover(udev->handler, ddev);
 185
 186         return 0;
 187 }
 188
 189 static int udev_handle_dev_add(struct pb_udev *udev, struct udev_device *dev)
 190 {
 191         const char *subsys;
 192         const char *name;
 193
 194         name = udev_device_get_sysname(dev);
 195         if (!name) {
 196                 pb_debug("udev_device_get_sysname failed\n");
 197                 return -1;
 198         }
 199
 200         subsys = udev_device_get_subsystem(dev);
 201         if (!subsys) {
 202                 pb_debug("udev_device_get_subsystem failed\n");
 203                 return -1;
 204         }
 205
 206         if (device_lookup_by_id(udev->handler, name)) {
 207                 pb_debug("device %s is already present?\n", name);
 208                 return -1;
 209         }
 210
 211         if (!strcmp(subsys, "block")) {
 212                 return udev_handle_block_add(udev, dev, name);
 213         }
 214
 215         pb_log("SKIP %s: unknown subsystem %s\n", name, subsys);
 216         return -1;
 217 }
 218
 219
 220 static int udev_handle_dev_remove(struct pb_udev *udev, struct udev_device *dev)
 221 {
 222         struct discover_device *ddev;
 223         const char *name;
 224
 225         name = udev_device_get_sysname(dev);
 226         if (!name) {
 227                 pb_debug("udev_device_get_sysname failed\n");
 228                 return -1;
 229         }
 230
 231         ddev = device_lookup_by_id(udev->handler, name);
 232         if (!ddev)
 233                 return 0;
 234
 235         device_handler_remove(udev->handler, ddev);
 236
 237         return 0;
 238 }
 239
 240 /* returns true if further event processing should stop (eg., we've
 241  * ejected the cdrom)
 242  */
 243 static bool udev_handle_cdrom_events(struct pb_udev *udev,
 244                 struct udev_device *dev, struct discover_device *ddev)
 245 {
 246         const char *node;
 247         bool eject = false;
 248
 249         node = udev_device_get_devnode(dev);
 250
 251         /* handle CDROM eject requests */
 252         if (udev_device_get_property_value(dev, "DISK_EJECT_REQUEST")) {
 253                 pb_debug("udev: eject request\n");
 254
 255                 /* If the device is mounted, cdrom_id's own eject request may
 256                  * have failed. So, we'll need to do our own here.
 257                  */
 258                 if (ddev) {
 259                         eject = ddev->mounted;
 260                         udev_handle_dev_remove(udev, dev);
 261                 }
 262
 263                 if (eject)
 264                         cdrom_eject(node);
 265
 266                 return true;
 267         }
 268
 269         if (udev_device_get_property_value(dev, "DISK_MEDIA_CHANGE")) {
 270                 if (cdrom_media_present(node))
 271                         udev_handle_dev_add(udev, dev);
 272                 else
 273                         udev_handle_dev_remove(udev, dev);
 274                 return true;
 275         }
 276
 277         return false;
 278 }
 279
 280 static int udev_handle_dev_change(struct pb_udev *udev, struct udev_device *dev)
 281 {
 282         struct discover_device *ddev;
 283         const char *name;
 284         int rc = 0;
 285
 286         name = udev_device_get_sysname(dev);
 287
 288         ddev = device_lookup_by_id(udev->handler, name);
 289
 290         /* if this is a CDROM device, process eject & media change requests;
 291          * these may stop further processing */
 292         if (!udev_device_get_property_value(dev, "ID_CDROM")) {
 293                 if (udev_handle_cdrom_events(udev, dev, ddev))
 294                         return 0;
 295         }
 296
 297         /* if this is a new device, treat it as an add */
 298         if (!ddev)
 299                 rc = udev_handle_dev_add(udev, dev);
 300
 301         return rc;
 302 }
 303
 304 static int udev_handle_dev_action(struct udev_device *dev, const char *action)
 305 {
 306         struct pb_udev *udev = udev_get_userdata(udev_device_get_udev(dev));
 307         struct udev_list_entry *list;
 308         const char *name;
 309
 310         list = udev_device_get_properties_list_entry(dev);
 311         name = udev_device_get_sysname(dev);
 312
 313         pb_debug("udev: action %s, device %s\n", action, name);
 314         pb_debug("udev: properties:\n");
 315
 316         for (; list; list = udev_list_entry_get_next(list))
 317                 pb_debug("\t%-20s: %s\n", udev_list_entry_get_name(list),
 318                                 udev_list_entry_get_value(list));
 319
 320         if (!strcmp(action, "add"))
 321                 return udev_handle_dev_add(udev, dev);
 322
 323         else if (!strcmp(action, "remove"))
 324                 return udev_handle_dev_remove(udev, dev);
 325
 326         else if (!strcmp(action, "change"))
 327                 return udev_handle_dev_change(udev, dev);
 328
 329         return 0;
 330 }
 331
 332 static int udev_enumerate(struct udev *udev)
 333 {
 334         int result;
 335         struct udev_list_entry *list, *entry;
 336         struct udev_enumerate *enumerate;
 337
 338         enumerate = udev_enumerate_new(udev);
 339
 340         if (!enumerate) {
 341                 pb_log("udev_enumerate_new failed\n");
 342                 return -1;
 343         }
 344
 345         result = udev_enumerate_add_match_subsystem(enumerate, "block");
 346         if (result) {
 347                 pb_log("udev_enumerate_add_match_subsystem failed\n");
 348                 goto fail;
 349         }
 350
 351         result = udev_enumerate_add_match_is_initialized(enumerate);
 352         if (result) {
 353                 pb_log("udev_enumerate_add_match_is_initialised failed\n");
 354                 goto fail;
 355         }
 356
 357         udev_enumerate_scan_devices(enumerate);
 358
 359         list = udev_enumerate_get_list_entry(enumerate);
 360
 361         udev_list_entry_foreach(entry, list) {
 362                 const char *syspath;
 363                 struct udev_device *dev;
 364
 365                 syspath = udev_list_entry_get_name(entry);
 366                 dev = udev_device_new_from_syspath(udev, syspath);
 367
 368                 udev_handle_dev_action(dev, "add");
 369
 370                 udev_device_unref(dev);
 371         }
 372
 373         udev_enumerate_unref(enumerate);
 374         return 0;
 375
 376 fail:
 377         udev_enumerate_unref(enumerate);
 378         return -1;
 379 }
 380
 381 static int udev_setup_monitor(struct udev *udev, struct udev_monitor **monitor)
 382 {
 383         int result;
 384         struct udev_monitor *m;
 385
 386         *monitor = NULL;
 387         m = udev_monitor_new_from_netlink(udev, "udev");
 388
 389         if (!m) {
 390                 pb_log("udev_monitor_new_from_netlink failed\n");
 391                 goto out_err;
 392         }
 393
 394         result = udev_monitor_set_receive_buffer_size(m, monitor_bufsize);
 395         if (result) {
 396                 pb_log("udev_monitor_set_rx_bufsize(%d) failed\n",
 397                         monitor_bufsize);
 398         }
 399
 400         result = udev_monitor_filter_add_match_subsystem_devtype(m, "block",
 401                 NULL);
 402
 403         if (result) {
 404                 pb_log("udev_monitor_filter_add_match_subsystem_devtype failed\n");
 405                 goto out_err;
 406         }
 407
 408         result = udev_monitor_enable_receiving(m);
 409
 410         if (result) {
 411                 pb_log("udev_monitor_enable_receiving failed\n");
 412                 goto out_err;
 413         }
 414
 415         *monitor = m;
 416         return 0;
 417
 418 out_err:
 419         udev_monitor_unref(m);
 420         return -1;
 421 }
 422
 423 /*
 424  * udev_process - waiter callback for monitor netlink.
 425  */
 426
 427 static int udev_process(void *arg)
 428 {
 429         struct udev_monitor *monitor = arg;
 430         struct udev_device *dev;
 431         const char *action;
 432
 433         dev = udev_monitor_receive_device(monitor);
 434         if (!dev) {
 435                 pb_log("udev_monitor_receive_device failed\n");
 436                 return -1;
 437         }
 438
 439         action = udev_device_get_action(dev);
 440
 441         if (!action) {
 442                 pb_log("udev_device_get_action failed\n");
 443         } else {
 444                 udev_handle_dev_action(dev, action);
 445         }
 446
 447         udev_device_unref(dev);
 448         return 0;
 449 }
 450
 451 #ifdef UDEV_LOGGING
 452 static void udev_log_fn(struct udev __attribute__((unused)) *udev,
 453         int __attribute__((unused)) priority, const char *file, int line,
 454         const char *fn, const char *format, va_list args)
 455 {
 456       pb_log("libudev: %s %s:%d: ", fn, file, line);
 457       vfprintf(pb_log_get_stream(), format, args);
 458 }
 459 #endif
 460
 461 struct pb_udev *udev_init(struct device_handler *handler,
 462                 struct waitset *waitset)
 463 {
 464         struct pb_udev *udev;
 465         int result;
 466
 467         udev = talloc_zero(handler, struct pb_udev);
 468         talloc_set_destructor(udev, udev_destructor);
 469         udev->handler = handler;
 470
 471         udev->udev = udev_new();
 472
 473         if (!udev->udev) {
 474                 pb_log("udev_new failed\n");
 475                 goto fail;
 476         }
 477
 478         udev_set_userdata(udev->udev, udev);
 479
 480 #ifdef UDEV_LOGGING
 481         udev_set_log_fn(udev->udev, udev_log_fn);
 482 #endif
 483
 484         result = udev_setup_monitor(udev->udev, &udev->monitor);
 485         if (result)
 486                 goto fail;
 487
 488         result = udev_enumerate(udev->udev);
 489         if (result)
 490                 goto fail;
 491
 492         waiter_register_io(waitset, udev_monitor_get_fd(udev->monitor), WAIT_IN,
 493                 udev_process, udev->monitor);
 494
 495         pb_debug("%s: waiting on udev\n", __func__);
 496
 497         return udev;
 498
 499 fail:
 500         talloc_free(udev);
 501         return NULL;
 502 }
 503
 504 void udev_reinit(struct pb_udev *udev)
 505 {
 506         pb_log("udev: reinit requested, starting enumeration\n");
 507         udev_enumerate(udev->udev);
 508 }