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 #include <process/process.h>
  23
  24 #include "event.h"
  25 #include "udev.h"
  26 #include "pb-discover.h"
  27 #include "device-handler.h"
  28 #include "cdrom.h"
  29 #include "devmapper.h"
  30
  31 /* We set a default monitor buffer size, as we may not process monitor
  32  * events while performing device discvoery. systemd uses a 128M buffer, so
  33  * we'll do the same here */
  34 static const int monitor_bufsize = 128 * 1024 * 1024;
  35
  36 struct pb_udev {
  37         struct udev *udev;
  38         struct udev_monitor *monitor;
  39         struct device_handler *handler;
  40 };
  41
  42 static int udev_destructor(void *p)
  43 {
  44         struct pb_udev *udev = p;
  45
  46         if (udev->monitor) {
  47                 udev_monitor_unref(udev->monitor);
  48                 udev->monitor = NULL;
  49         }
  50
  51         if (udev->udev) {
  52                 udev_unref(udev->udev);
  53                 udev->udev = NULL;
  54         }
  55
  56         return 0;
  57 }
  58
  59 static void udev_setup_device_params(struct udev_device *udev,
  60                 struct discover_device *dev)
  61 {
  62         struct udev_list_entry *list, *entry;
  63
  64         list = udev_device_get_properties_list_entry(udev);
  65         if (!list)
  66                 return;
  67
  68         udev_list_entry_foreach(entry, list)
  69                 discover_device_set_param(dev,
  70                                 udev_list_entry_get_name(entry),
  71                                 udev_list_entry_get_value(entry));
  72 }
  73
  74 /*
  75  * Search for LVM logical volumes. If any exist they should be recognised
  76  * by udev as normal.
  77  * Normally this is handled in an init script, but on some platforms
  78  * disks are slow enough to come up that we need to check again.
  79  */
  80 static void lvm_vg_search(struct device_handler *handler)
  81 {
  82         if (process_run_simple(handler, pb_system_apps.vgscan, "-qq", NULL))
  83                 pb_log("%s: Failed to execute vgscan\n", __func__);
  84
  85         if (process_run_simple(handler, pb_system_apps.vgchange, "-ay", "-qq",
  86                                 NULL))
  87                 pb_log("%s: Failed to execute vgchange\n", __func__);
  88 }
  89
  90 static int udev_handle_block_add(struct pb_udev *udev, struct udev_device *dev,
  91                 const char *name)
  92 {
  93         char *devlinks = NULL, *link, *saveptr = NULL;
  94         struct discover_device *ddev;
  95         unsigned int i = 0;
  96         const char *typestr;
  97         const char *uuid;
  98         const char *path;
  99         const char *node;
 100         const char *prop;
 101         const char *type;
 102         const char *devname;
 103         const char *ignored_types[] = {
 104                 "linux_raid_member",
 105                 "swap",
 106                 NULL,
 107         };
 108         bool cdrom, usb;
 109
 110         typestr = udev_device_get_devtype(dev);
 111         if (!typestr) {
 112                 pb_debug("udev_device_get_devtype failed\n");
 113                 return -1;
 114         }
 115
 116         if (!(!strcmp(typestr, "disk") || !strcmp(typestr, "partition"))) {
 117                 pb_log("SKIP %s: invalid type %s\n", name, typestr);
 118                 return 0;
 119         }
 120
 121         node = udev_device_get_devnode(dev);
 122         path = udev_device_get_devpath(dev);
 123         if (path && strstr(path, "virtual/block/loop")) {
 124                 pb_log("SKIP: %s: ignored (path=%s)\n", name, path);
 125                 return 0;
 126         }
 127
 128         if (path && strstr(path, "virtual/block/ram")) {
 129                 device_handler_add_ramdisk(udev->handler, node);
 130                 return 0;
 131         }
 132
 133         cdrom = node && !!udev_device_get_property_value(dev, "ID_CDROM");
 134         if (cdrom) {
 135                 /* CDROMs require a little initialisation, to get
 136                  * petitboot-compatible tray behaviour */
 137                 cdrom_init(node);
 138                 if (!cdrom_media_present(node)) {
 139                         pb_log("SKIP: %s: no media present\n", name);
 140                         return 0;
 141                 }
 142         }
 143
 144         /* Ignore any device mapper devices that aren't logical volumes */
 145         devname = udev_device_get_property_value(dev, "DM_NAME");
 146         if (devname && ! udev_device_get_property_value(dev, "DM_LV_NAME")) {
 147                 pb_debug("SKIP: dm-device %s\n", devname);
 148                 return 0;
 149         }
 150
 151         type = udev_device_get_property_value(dev, "ID_FS_TYPE");
 152         if (!type) {
 153                 pb_log("SKIP: %s: no ID_FS_TYPE property\n", name);
 154                 return 0;
 155         }
 156
 157         while (ignored_types[i]) {
 158                 if (!strncmp(type, ignored_types[i], strlen(ignored_types[i]))) {
 159                         pb_log("SKIP: %s: ignore '%s' filesystem\n", name, type);
 160                         return 0;
 161                 }
 162                 i++;
 163         }
 164
 165         /* Search for LVM logical volumes if we see an LVM member */
 166         if (strncmp(type, "LVM2_member", strlen("LVM2_member")) == 0) {
 167                 lvm_vg_search(udev->handler);
 168                 return 0;
 169         }
 170
 171         /* We may see multipath devices; they'll have the same uuid as an
 172          * existing device, so only parse the first. */
 173         uuid = udev_device_get_property_value(dev, "ID_FS_UUID");
 174         if (uuid) {
 175                 ddev = device_lookup_by_uuid(udev->handler, uuid);
 176                 if (ddev) {
 177                         pb_log("SKIP: %s UUID [%s] already present (as %s)\n",
 178                                         name, uuid, ddev->device->id);
 179                         return 0;
 180                 }
 181         }
 182
 183         /* Use DM_NAME for logical volumes, or the device name otherwise */
 184         ddev = discover_device_create(udev->handler, uuid, devname ?: name);
 185
 186         if (devname) {
 187                 /*
 188                  * For logical volumes udev_device_get_devnode() returns a path
 189                  * of the form "/dev/dm-xx". These nodes names are not
 190                  * persistent and are opaque to the user. Instead use the more
 191                  * recognisable "/dev/mapper/lv-name" node if it is available.
 192                  */
 193                 devlinks = talloc_strdup(ddev,
 194                                 udev_device_get_property_value(dev, "DEVLINKS"));
 195                 link = devlinks ? strtok_r(devlinks, " ", &saveptr) : NULL;
 196                 while (link) {
 197                         if (strncmp(link, "/dev/mapper/",
 198                                         strlen("/dev/mapper/")) == 0) {
 199                                 node = link;
 200                                 break;
 201                         }
 202                         link = strtok_r(NULL, " ", &saveptr);
 203                 }
 204         }
 205
 206         ddev->device_path = talloc_strdup(ddev, node);
 207         talloc_free(devlinks);
 208
 209         if (uuid)
 210                 ddev->uuid = talloc_strdup(ddev, uuid);
 211         prop = udev_device_get_property_value(dev, "ID_FS_LABEL");
 212         if (prop)
 213                 ddev->label = talloc_strdup(ddev, prop);
 214
 215         usb = !!udev_device_get_property_value(dev, "ID_USB_DRIVER");
 216         if (cdrom)
 217                 ddev->device->type = DEVICE_TYPE_OPTICAL;
 218         else
 219                 ddev->device->type = usb ? DEVICE_TYPE_USB : DEVICE_TYPE_DISK;
 220
 221         udev_setup_device_params(dev, ddev);
 222
 223         /* Create a snapshot for all disk devices */
 224         if ((ddev->device->type == DEVICE_TYPE_DISK ||
 225              ddev->device->type == DEVICE_TYPE_USB))
 226                 devmapper_init_snapshot(udev->handler, ddev);
 227
 228         device_handler_discover(udev->handler, ddev);
 229
 230         return 0;
 231 }
 232
 233 static int udev_handle_dev_add(struct pb_udev *udev, struct udev_device *dev)
 234 {
 235         const char *subsys;
 236         const char *name;
 237
 238         name = udev_device_get_sysname(dev);
 239         if (!name) {
 240                 pb_debug("udev_device_get_sysname failed\n");
 241                 return -1;
 242         }
 243
 244         subsys = udev_device_get_subsystem(dev);
 245         if (!subsys) {
 246                 pb_debug("udev_device_get_subsystem failed\n");
 247                 return -1;
 248         }
 249
 250         if (device_lookup_by_id(udev->handler, name)) {
 251                 pb_debug("device %s is already present?\n", name);
 252                 return -1;
 253         }
 254
 255         if (!strcmp(subsys, "block")) {
 256                 return udev_handle_block_add(udev, dev, name);
 257         }
 258
 259         pb_log("SKIP %s: unknown subsystem %s\n", name, subsys);
 260         return -1;
 261 }
 262
 263
 264 static int udev_handle_dev_remove(struct pb_udev *udev, struct udev_device *dev)
 265 {
 266         struct discover_device *ddev;
 267         const char *name;
 268
 269         name = udev_device_get_sysname(dev);
 270         if (!name) {
 271                 pb_debug("udev_device_get_sysname failed\n");
 272                 return -1;
 273         }
 274
 275         ddev = device_lookup_by_id(udev->handler, name);
 276         if (!ddev)
 277                 return 0;
 278
 279         device_handler_remove(udev->handler, ddev);
 280
 281         return 0;
 282 }
 283
 284 /* returns true if further event processing should stop (eg., we've
 285  * ejected the cdrom)
 286  */
 287 static bool udev_handle_cdrom_events(struct pb_udev *udev,
 288                 struct udev_device *dev, struct discover_device *ddev)
 289 {
 290         const char *node;
 291         bool eject = false;
 292
 293         node = udev_device_get_devnode(dev);
 294
 295         /* handle CDROM eject requests */
 296         if (udev_device_get_property_value(dev, "DISK_EJECT_REQUEST")) {
 297                 pb_debug("udev: eject request\n");
 298
 299                 /* If the device is mounted, cdrom_id's own eject request may
 300                  * have failed. So, we'll need to do our own here.
 301                  */
 302                 if (ddev) {
 303                         eject = ddev->mounted;
 304                         udev_handle_dev_remove(udev, dev);
 305                 }
 306
 307                 if (eject)
 308                         cdrom_eject(node);
 309
 310                 return true;
 311         }
 312
 313         if (udev_device_get_property_value(dev, "DISK_MEDIA_CHANGE")) {
 314                 if (cdrom_media_present(node))
 315                         udev_handle_dev_add(udev, dev);
 316                 else
 317                         udev_handle_dev_remove(udev, dev);
 318                 return true;
 319         }
 320
 321         return false;
 322 }
 323
 324 static int udev_handle_dev_change(struct pb_udev *udev, struct udev_device *dev)
 325 {
 326         struct discover_device *ddev;
 327         const char *name;
 328         int rc = 0;
 329
 330         name = udev_device_get_sysname(dev);
 331
 332         ddev = device_lookup_by_id(udev->handler, name);
 333
 334         /* if this is a CDROM device, process eject & media change requests;
 335          * these may stop further processing */
 336         if (!udev_device_get_property_value(dev, "ID_CDROM")) {
 337                 if (udev_handle_cdrom_events(udev, dev, ddev))
 338                         return 0;
 339         }
 340
 341         /* if this is a new device, treat it as an add */
 342         if (!ddev)
 343                 rc = udev_handle_dev_add(udev, dev);
 344
 345         return rc;
 346 }
 347
 348 static int udev_handle_dev_action(struct udev_device *dev, const char *action)
 349 {
 350         struct pb_udev *udev = udev_get_userdata(udev_device_get_udev(dev));
 351         struct udev_list_entry *list;
 352         const char *name;
 353
 354         list = udev_device_get_properties_list_entry(dev);
 355         name = udev_device_get_sysname(dev);
 356
 357         pb_debug("udev: action %s, device %s\n", action, name);
 358         pb_debug("udev: properties:\n");
 359
 360         for (; list; list = udev_list_entry_get_next(list))
 361                 pb_debug("\t%-20s: %s\n", udev_list_entry_get_name(list),
 362                                 udev_list_entry_get_value(list));
 363
 364         if (!strcmp(action, "add"))
 365                 return udev_handle_dev_add(udev, dev);
 366
 367         else if (!strcmp(action, "remove"))
 368                 return udev_handle_dev_remove(udev, dev);
 369
 370         else if (!strcmp(action, "change"))
 371                 return udev_handle_dev_change(udev, dev);
 372
 373         return 0;
 374 }
 375
 376 static int udev_enumerate(struct udev *udev)
 377 {
 378         int result;
 379         struct udev_list_entry *list, *entry;
 380         struct udev_enumerate *enumerate;
 381
 382         enumerate = udev_enumerate_new(udev);
 383
 384         if (!enumerate) {
 385                 pb_log("udev_enumerate_new failed\n");
 386                 return -1;
 387         }
 388
 389         result = udev_enumerate_add_match_subsystem(enumerate, "block");
 390         if (result) {
 391                 pb_log("udev_enumerate_add_match_subsystem failed\n");
 392                 goto fail;
 393         }
 394
 395         result = udev_enumerate_add_match_is_initialized(enumerate);
 396         if (result) {
 397                 pb_log("udev_enumerate_add_match_is_initialised failed\n");
 398                 goto fail;
 399         }
 400
 401         udev_enumerate_scan_devices(enumerate);
 402
 403         list = udev_enumerate_get_list_entry(enumerate);
 404
 405         udev_list_entry_foreach(entry, list) {
 406                 const char *syspath;
 407                 struct udev_device *dev;
 408
 409                 syspath = udev_list_entry_get_name(entry);
 410                 dev = udev_device_new_from_syspath(udev, syspath);
 411
 412                 udev_handle_dev_action(dev, "add");
 413
 414                 udev_device_unref(dev);
 415         }
 416
 417         udev_enumerate_unref(enumerate);
 418         return 0;
 419
 420 fail:
 421         udev_enumerate_unref(enumerate);
 422         return -1;
 423 }
 424
 425 static int udev_setup_monitor(struct udev *udev, struct udev_monitor **monitor)
 426 {
 427         int result;
 428         struct udev_monitor *m;
 429
 430         *monitor = NULL;
 431         m = udev_monitor_new_from_netlink(udev, "udev");
 432
 433         if (!m) {
 434                 pb_log("udev_monitor_new_from_netlink failed\n");
 435                 goto out_err;
 436         }
 437
 438         result = udev_monitor_set_receive_buffer_size(m, monitor_bufsize);
 439         if (result) {
 440                 pb_log("udev_monitor_set_rx_bufsize(%d) failed\n",
 441                         monitor_bufsize);
 442         }
 443
 444         result = udev_monitor_filter_add_match_subsystem_devtype(m, "block",
 445                 NULL);
 446
 447         if (result) {
 448                 pb_log("udev_monitor_filter_add_match_subsystem_devtype failed\n");
 449                 goto out_err;
 450         }
 451
 452         result = udev_monitor_enable_receiving(m);
 453
 454         if (result) {
 455                 pb_log("udev_monitor_enable_receiving failed\n");
 456                 goto out_err;
 457         }
 458
 459         *monitor = m;
 460         return 0;
 461
 462 out_err:
 463         udev_monitor_unref(m);
 464         return -1;
 465 }
 466
 467 /*
 468  * udev_process - waiter callback for monitor netlink.
 469  */
 470
 471 static int udev_process(void *arg)
 472 {
 473         struct udev_monitor *monitor = arg;
 474         struct udev_device *dev;
 475         const char *action;
 476
 477         dev = udev_monitor_receive_device(monitor);
 478         if (!dev) {
 479                 pb_log("udev_monitor_receive_device failed\n");
 480                 return -1;
 481         }
 482
 483         action = udev_device_get_action(dev);
 484
 485         if (!action) {
 486                 pb_log("udev_device_get_action failed\n");
 487         } else {
 488                 udev_handle_dev_action(dev, action);
 489         }
 490
 491         udev_device_unref(dev);
 492         return 0;
 493 }
 494
 495 #ifdef UDEV_LOGGING
 496 static void udev_log_fn(struct udev __attribute__((unused)) *udev,
 497         int __attribute__((unused)) priority, const char *file, int line,
 498         const char *fn, const char *format, va_list args)
 499 {
 500       pb_log("libudev: %s %s:%d: ", fn, file, line);
 501       vfprintf(pb_log_get_stream(), format, args);
 502 }
 503 #endif
 504
 505 struct pb_udev *udev_init(struct device_handler *handler,
 506                 struct waitset *waitset)
 507 {
 508         struct pb_udev *udev;
 509         int result;
 510
 511         udev = talloc_zero(handler, struct pb_udev);
 512         talloc_set_destructor(udev, udev_destructor);
 513         udev->handler = handler;
 514
 515         udev->udev = udev_new();
 516
 517         if (!udev->udev) {
 518                 pb_log("udev_new failed\n");
 519                 goto fail;
 520         }
 521
 522         udev_set_userdata(udev->udev, udev);
 523
 524 #ifdef UDEV_LOGGING
 525         udev_set_log_fn(udev->udev, udev_log_fn);
 526 #endif
 527
 528         result = udev_setup_monitor(udev->udev, &udev->monitor);
 529         if (result)
 530                 goto fail;
 531
 532         result = udev_enumerate(udev->udev);
 533         if (result)
 534                 goto fail;
 535
 536         waiter_register_io(waitset, udev_monitor_get_fd(udev->monitor), WAIT_IN,
 537                 udev_process, udev->monitor);
 538
 539         pb_debug("%s: waiting on udev\n", __func__);
 540
 541         return udev;
 542
 543 fail:
 544         talloc_free(udev);
 545         return NULL;
 546 }
 547
 548 void udev_reinit(struct pb_udev *udev)
 549 {
 550         pb_log("udev: reinit requested, starting enumeration\n");
 551         udev_enumerate(udev->udev);
 552 }