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;
  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         ddev->device->type = cdrom ? DEVICE_TYPE_OPTICAL : DEVICE_TYPE_DISK;
 171
 172         udev_setup_device_params(dev, ddev);
 173
 174         /* Create a snapshot for all disks, unless it is an assembled RAID array */
 175         if (ddev->device->type == DEVICE_TYPE_DISK &&
 176             !udev_device_get_property_value(dev, "MD_LEVEL"))
 177                 devmapper_init_snapshot(udev->handler, ddev);
 178
 179         device_handler_discover(udev->handler, ddev);
 180
 181         return 0;
 182 }
 183
 184 static int udev_handle_dev_add(struct pb_udev *udev, struct udev_device *dev)
 185 {
 186         const char *subsys;
 187         const char *name;
 188
 189         name = udev_device_get_sysname(dev);
 190         if (!name) {
 191                 pb_debug("udev_device_get_sysname failed\n");
 192                 return -1;
 193         }
 194
 195         subsys = udev_device_get_subsystem(dev);
 196         if (!subsys) {
 197                 pb_debug("udev_device_get_subsystem failed\n");
 198                 return -1;
 199         }
 200
 201         if (device_lookup_by_id(udev->handler, name)) {
 202                 pb_debug("device %s is already present?\n", name);
 203                 return -1;
 204         }
 205
 206         if (!strcmp(subsys, "block")) {
 207                 return udev_handle_block_add(udev, dev, name);
 208         }
 209
 210         pb_log("SKIP %s: unknown subsystem %s\n", name, subsys);
 211         return -1;
 212 }
 213
 214
 215 static int udev_handle_dev_remove(struct pb_udev *udev, struct udev_device *dev)
 216 {
 217         struct discover_device *ddev;
 218         const char *name;
 219
 220         name = udev_device_get_sysname(dev);
 221         if (!name) {
 222                 pb_debug("udev_device_get_sysname failed\n");
 223                 return -1;
 224         }
 225
 226         ddev = device_lookup_by_id(udev->handler, name);
 227         if (!ddev)
 228                 return 0;
 229
 230         device_handler_remove(udev->handler, ddev);
 231
 232         return 0;
 233 }
 234
 235 /* returns true if further event processing should stop (eg., we've
 236  * ejected the cdrom)
 237  */
 238 static bool udev_handle_cdrom_events(struct pb_udev *udev,
 239                 struct udev_device *dev, struct discover_device *ddev)
 240 {
 241         const char *node;
 242
 243         node = udev_device_get_devnode(dev);
 244
 245         /* handle CDROM eject requests */
 246         if (udev_device_get_property_value(dev, "DISK_EJECT_REQUEST")) {
 247                 bool eject = false;
 248
 249                 pb_debug("udev: eject request\n");
 250
 251                 /* If the device is mounted, cdrom_id's own eject request may
 252                  * have failed. So, we'll need to do our own here.
 253                  */
 254                 if (ddev) {
 255                         eject = ddev->mounted;
 256                         udev_handle_dev_remove(udev, dev);
 257                         return false;
 258                 }
 259
 260                 if (eject)
 261                         cdrom_eject(node);
 262
 263                 return true;
 264         }
 265
 266         if (udev_device_get_property_value(dev, "DISK_MEDIA_CHANGE")) {
 267                 if (cdrom_media_present(node))
 268                         udev_handle_dev_add(udev, dev);
 269                 else
 270                         udev_handle_dev_remove(udev, dev);
 271                 return true;
 272         }
 273
 274         return false;
 275 }
 276
 277 static int udev_handle_dev_change(struct pb_udev *udev, struct udev_device *dev)
 278 {
 279         struct discover_device *ddev;
 280         const char *name;
 281         int rc = 0;
 282
 283         name = udev_device_get_sysname(dev);
 284
 285         ddev = device_lookup_by_id(udev->handler, name);
 286
 287         /* if this is a CDROM device, process eject & media change requests;
 288          * these may stop further processing */
 289         if (!udev_device_get_property_value(dev, "ID_CDROM")) {
 290                 if (udev_handle_cdrom_events(udev, dev, ddev))
 291                         return 0;
 292         }
 293
 294         /* if this is a new device, treat it as an add */
 295         if (!ddev)
 296                 rc = udev_handle_dev_add(udev, dev);
 297
 298         return rc;
 299 }
 300
 301 static int udev_handle_dev_action(struct udev_device *dev, const char *action)
 302 {
 303         struct pb_udev *udev = udev_get_userdata(udev_device_get_udev(dev));
 304         struct udev_list_entry *list;
 305         const char *name;
 306
 307         list = udev_device_get_properties_list_entry(dev);
 308         name = udev_device_get_sysname(dev);
 309
 310         pb_debug("udev: action %s, device %s\n", action, name);
 311         pb_debug("udev: properties:\n");
 312
 313         for (; list; list = udev_list_entry_get_next(list))
 314                 pb_debug("\t%-20s: %s\n", udev_list_entry_get_name(list),
 315                                 udev_list_entry_get_value(list));
 316
 317         if (!strcmp(action, "add"))
 318                 return udev_handle_dev_add(udev, dev);
 319
 320         else if (!strcmp(action, "remove"))
 321                 return udev_handle_dev_remove(udev, dev);
 322
 323         else if (!strcmp(action, "change"))
 324                 return udev_handle_dev_change(udev, dev);
 325
 326         return 0;
 327 }
 328
 329 static int udev_enumerate(struct udev *udev)
 330 {
 331         int result;
 332         struct udev_list_entry *list, *entry;
 333         struct udev_enumerate *enumerate;
 334
 335         enumerate = udev_enumerate_new(udev);
 336
 337         if (!enumerate) {
 338                 pb_log("udev_enumerate_new failed\n");
 339                 return -1;
 340         }
 341
 342         result = udev_enumerate_add_match_subsystem(enumerate, "block");
 343         if (result) {
 344                 pb_log("udev_enumerate_add_match_subsystem failed\n");
 345                 goto fail;
 346         }
 347
 348         result = udev_enumerate_add_match_is_initialized(enumerate);
 349         if (result) {
 350                 pb_log("udev_enumerate_add_match_is_initialised failed\n");
 351                 goto fail;
 352         }
 353
 354         udev_enumerate_scan_devices(enumerate);
 355
 356         list = udev_enumerate_get_list_entry(enumerate);
 357
 358         udev_list_entry_foreach(entry, list) {
 359                 const char *syspath;
 360                 struct udev_device *dev;
 361
 362                 syspath = udev_list_entry_get_name(entry);
 363                 dev = udev_device_new_from_syspath(udev, syspath);
 364
 365                 udev_handle_dev_action(dev, "add");
 366
 367                 udev_device_unref(dev);
 368         }
 369
 370         udev_enumerate_unref(enumerate);
 371         return 0;
 372
 373 fail:
 374         udev_enumerate_unref(enumerate);
 375         return -1;
 376 }
 377
 378 static int udev_setup_monitor(struct udev *udev, struct udev_monitor **monitor)
 379 {
 380         int result;
 381         struct udev_monitor *m;
 382
 383         *monitor = NULL;
 384         m = udev_monitor_new_from_netlink(udev, "udev");
 385
 386         if (!m) {
 387                 pb_log("udev_monitor_new_from_netlink failed\n");
 388                 goto out_err;
 389         }
 390
 391         result = udev_monitor_set_receive_buffer_size(m, monitor_bufsize);
 392         if (result) {
 393                 pb_log("udev_monitor_set_rx_bufsize(%d) failed\n",
 394                         monitor_bufsize);
 395         }
 396
 397         result = udev_monitor_filter_add_match_subsystem_devtype(m, "block",
 398                 NULL);
 399
 400         if (result) {
 401                 pb_log("udev_monitor_filter_add_match_subsystem_devtype failed\n");
 402                 goto out_err;
 403         }
 404
 405         result = udev_monitor_enable_receiving(m);
 406
 407         if (result) {
 408                 pb_log("udev_monitor_enable_receiving failed\n");
 409                 goto out_err;
 410         }
 411
 412         *monitor = m;
 413         return 0;
 414
 415 out_err:
 416         udev_monitor_unref(m);
 417         return -1;
 418 }
 419
 420 /*
 421  * udev_process - waiter callback for monitor netlink.
 422  */
 423
 424 static int udev_process(void *arg)
 425 {
 426         struct udev_monitor *monitor = arg;
 427         struct udev_device *dev;
 428         const char *action;
 429
 430         dev = udev_monitor_receive_device(monitor);
 431         if (!dev) {
 432                 pb_log("udev_monitor_receive_device failed\n");
 433                 return -1;
 434         }
 435
 436         action = udev_device_get_action(dev);
 437
 438         if (!action) {
 439                 pb_log("udev_device_get_action failed\n");
 440         } else {
 441                 udev_handle_dev_action(dev, action);
 442         }
 443
 444         udev_device_unref(dev);
 445         return 0;
 446 }
 447
 448 static void udev_log_fn(struct udev __attribute__((unused)) *udev,
 449         int __attribute__((unused)) priority, const char *file, int line,
 450         const char *fn, const char *format, va_list args)
 451 {
 452       pb_log("libudev: %s %s:%d: ", fn, file, line);
 453       vfprintf(pb_log_get_stream(), format, args);
 454 }
 455
 456 struct pb_udev *udev_init(struct device_handler *handler,
 457                 struct waitset *waitset)
 458 {
 459         struct pb_udev *udev;
 460         int result;
 461
 462         udev = talloc_zero(handler, struct pb_udev);
 463         talloc_set_destructor(udev, udev_destructor);
 464         udev->handler = handler;
 465
 466         udev->udev = udev_new();
 467
 468         if (!udev->udev) {
 469                 pb_log("udev_new failed\n");
 470                 goto fail;
 471         }
 472
 473         udev_set_userdata(udev->udev, udev);
 474
 475         udev_set_log_fn(udev->udev, udev_log_fn);
 476
 477         result = udev_setup_monitor(udev->udev, &udev->monitor);
 478         if (result)
 479                 goto fail;
 480
 481         result = udev_enumerate(udev->udev);
 482         if (result)
 483                 goto fail;
 484
 485         waiter_register_io(waitset, udev_monitor_get_fd(udev->monitor), WAIT_IN,
 486                 udev_process, udev->monitor);
 487
 488         pb_debug("%s: waiting on udev\n", __func__);
 489
 490         return udev;
 491
 492 fail:
 493         talloc_free(udev);
 494         return NULL;
 495 }
 496
 497 void udev_reinit(struct pb_udev *udev)
 498 {
 499         pb_log("udev: reinit requested, starting enumeration\n");
 500         udev_enumerate(udev->udev);
 501 }