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 disks, unless it is an assembled RAID array */
 180         if ((ddev->device->type == DEVICE_TYPE_DISK ||
 181              ddev->device->type == DEVICE_TYPE_USB) &&
 182             !udev_device_get_property_value(dev, "MD_LEVEL"))
 183                 devmapper_init_snapshot(udev->handler, ddev);
 184
 185         device_handler_discover(udev->handler, ddev);
 186
 187         return 0;
 188 }
 189
 190 static int udev_handle_dev_add(struct pb_udev *udev, struct udev_device *dev)
 191 {
 192         const char *subsys;
 193         const char *name;
 194
 195         name = udev_device_get_sysname(dev);
 196         if (!name) {
 197                 pb_debug("udev_device_get_sysname failed\n");
 198                 return -1;
 199         }
 200
 201         subsys = udev_device_get_subsystem(dev);
 202         if (!subsys) {
 203                 pb_debug("udev_device_get_subsystem failed\n");
 204                 return -1;
 205         }
 206
 207         if (device_lookup_by_id(udev->handler, name)) {
 208                 pb_debug("device %s is already present?\n", name);
 209                 return -1;
 210         }
 211
 212         if (!strcmp(subsys, "block")) {
 213                 return udev_handle_block_add(udev, dev, name);
 214         }
 215
 216         pb_log("SKIP %s: unknown subsystem %s\n", name, subsys);
 217         return -1;
 218 }
 219
 220
 221 static int udev_handle_dev_remove(struct pb_udev *udev, struct udev_device *dev)
 222 {
 223         struct discover_device *ddev;
 224         const char *name;
 225
 226         name = udev_device_get_sysname(dev);
 227         if (!name) {
 228                 pb_debug("udev_device_get_sysname failed\n");
 229                 return -1;
 230         }
 231
 232         ddev = device_lookup_by_id(udev->handler, name);
 233         if (!ddev)
 234                 return 0;
 235
 236         device_handler_remove(udev->handler, ddev);
 237
 238         return 0;
 239 }
 240
 241 /* returns true if further event processing should stop (eg., we've
 242  * ejected the cdrom)
 243  */
 244 static bool udev_handle_cdrom_events(struct pb_udev *udev,
 245                 struct udev_device *dev, struct discover_device *ddev)
 246 {
 247         const char *node;
 248         bool eject = false;
 249
 250         node = udev_device_get_devnode(dev);
 251
 252         /* handle CDROM eject requests */
 253         if (udev_device_get_property_value(dev, "DISK_EJECT_REQUEST")) {
 254                 pb_debug("udev: eject request\n");
 255
 256                 /* If the device is mounted, cdrom_id's own eject request may
 257                  * have failed. So, we'll need to do our own here.
 258                  */
 259                 if (ddev) {
 260                         eject = ddev->mounted;
 261                         udev_handle_dev_remove(udev, dev);
 262                 }
 263
 264                 if (eject)
 265                         cdrom_eject(node);
 266
 267                 return true;
 268         }
 269
 270         if (udev_device_get_property_value(dev, "DISK_MEDIA_CHANGE")) {
 271                 if (cdrom_media_present(node))
 272                         udev_handle_dev_add(udev, dev);
 273                 else
 274                         udev_handle_dev_remove(udev, dev);
 275                 return true;
 276         }
 277
 278         return false;
 279 }
 280
 281 static int udev_handle_dev_change(struct pb_udev *udev, struct udev_device *dev)
 282 {
 283         struct discover_device *ddev;
 284         const char *name;
 285         int rc = 0;
 286
 287         name = udev_device_get_sysname(dev);
 288
 289         ddev = device_lookup_by_id(udev->handler, name);
 290
 291         /* if this is a CDROM device, process eject & media change requests;
 292          * these may stop further processing */
 293         if (!udev_device_get_property_value(dev, "ID_CDROM")) {
 294                 if (udev_handle_cdrom_events(udev, dev, ddev))
 295                         return 0;
 296         }
 297
 298         /* if this is a new device, treat it as an add */
 299         if (!ddev)
 300                 rc = udev_handle_dev_add(udev, dev);
 301
 302         return rc;
 303 }
 304
 305 static int udev_handle_dev_action(struct udev_device *dev, const char *action)
 306 {
 307         struct pb_udev *udev = udev_get_userdata(udev_device_get_udev(dev));
 308         struct udev_list_entry *list;
 309         const char *name;
 310
 311         list = udev_device_get_properties_list_entry(dev);
 312         name = udev_device_get_sysname(dev);
 313
 314         pb_debug("udev: action %s, device %s\n", action, name);
 315         pb_debug("udev: properties:\n");
 316
 317         for (; list; list = udev_list_entry_get_next(list))
 318                 pb_debug("\t%-20s: %s\n", udev_list_entry_get_name(list),
 319                                 udev_list_entry_get_value(list));
 320
 321         if (!strcmp(action, "add"))
 322                 return udev_handle_dev_add(udev, dev);
 323
 324         else if (!strcmp(action, "remove"))
 325                 return udev_handle_dev_remove(udev, dev);
 326
 327         else if (!strcmp(action, "change"))
 328                 return udev_handle_dev_change(udev, dev);
 329
 330         return 0;
 331 }
 332
 333 static int udev_enumerate(struct udev *udev)
 334 {
 335         int result;
 336         struct udev_list_entry *list, *entry;
 337         struct udev_enumerate *enumerate;
 338
 339         enumerate = udev_enumerate_new(udev);
 340
 341         if (!enumerate) {
 342                 pb_log("udev_enumerate_new failed\n");
 343                 return -1;
 344         }
 345
 346         result = udev_enumerate_add_match_subsystem(enumerate, "block");
 347         if (result) {
 348                 pb_log("udev_enumerate_add_match_subsystem failed\n");
 349                 goto fail;
 350         }
 351
 352         result = udev_enumerate_add_match_is_initialized(enumerate);
 353         if (result) {
 354                 pb_log("udev_enumerate_add_match_is_initialised failed\n");
 355                 goto fail;
 356         }
 357
 358         udev_enumerate_scan_devices(enumerate);
 359
 360         list = udev_enumerate_get_list_entry(enumerate);
 361
 362         udev_list_entry_foreach(entry, list) {
 363                 const char *syspath;
 364                 struct udev_device *dev;
 365
 366                 syspath = udev_list_entry_get_name(entry);
 367                 dev = udev_device_new_from_syspath(udev, syspath);
 368
 369                 udev_handle_dev_action(dev, "add");
 370
 371                 udev_device_unref(dev);
 372         }
 373
 374         udev_enumerate_unref(enumerate);
 375         return 0;
 376
 377 fail:
 378         udev_enumerate_unref(enumerate);
 379         return -1;
 380 }
 381
 382 static int udev_setup_monitor(struct udev *udev, struct udev_monitor **monitor)
 383 {
 384         int result;
 385         struct udev_monitor *m;
 386
 387         *monitor = NULL;
 388         m = udev_monitor_new_from_netlink(udev, "udev");
 389
 390         if (!m) {
 391                 pb_log("udev_monitor_new_from_netlink failed\n");
 392                 goto out_err;
 393         }
 394
 395         result = udev_monitor_set_receive_buffer_size(m, monitor_bufsize);
 396         if (result) {
 397                 pb_log("udev_monitor_set_rx_bufsize(%d) failed\n",
 398                         monitor_bufsize);
 399         }
 400
 401         result = udev_monitor_filter_add_match_subsystem_devtype(m, "block",
 402                 NULL);
 403
 404         if (result) {
 405                 pb_log("udev_monitor_filter_add_match_subsystem_devtype failed\n");
 406                 goto out_err;
 407         }
 408
 409         result = udev_monitor_enable_receiving(m);
 410
 411         if (result) {
 412                 pb_log("udev_monitor_enable_receiving failed\n");
 413                 goto out_err;
 414         }
 415
 416         *monitor = m;
 417         return 0;
 418
 419 out_err:
 420         udev_monitor_unref(m);
 421         return -1;
 422 }
 423
 424 /*
 425  * udev_process - waiter callback for monitor netlink.
 426  */
 427
 428 static int udev_process(void *arg)
 429 {
 430         struct udev_monitor *monitor = arg;
 431         struct udev_device *dev;
 432         const char *action;
 433
 434         dev = udev_monitor_receive_device(monitor);
 435         if (!dev) {
 436                 pb_log("udev_monitor_receive_device failed\n");
 437                 return -1;
 438         }
 439
 440         action = udev_device_get_action(dev);
 441
 442         if (!action) {
 443                 pb_log("udev_device_get_action failed\n");
 444         } else {
 445                 udev_handle_dev_action(dev, action);
 446         }
 447
 448         udev_device_unref(dev);
 449         return 0;
 450 }
 451
 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
 460 struct pb_udev *udev_init(struct device_handler *handler,
 461                 struct waitset *waitset)
 462 {
 463         struct pb_udev *udev;
 464         int result;
 465
 466         udev = talloc_zero(handler, struct pb_udev);
 467         talloc_set_destructor(udev, udev_destructor);
 468         udev->handler = handler;
 469
 470         udev->udev = udev_new();
 471
 472         if (!udev->udev) {
 473                 pb_log("udev_new failed\n");
 474                 goto fail;
 475         }
 476
 477         udev_set_userdata(udev->udev, udev);
 478
 479         udev_set_log_fn(udev->udev, udev_log_fn);
 480
 481         result = udev_setup_monitor(udev->udev, &udev->monitor);
 482         if (result)
 483                 goto fail;
 484
 485         result = udev_enumerate(udev->udev);
 486         if (result)
 487                 goto fail;
 488
 489         waiter_register_io(waitset, udev_monitor_get_fd(udev->monitor), WAIT_IN,
 490                 udev_process, udev->monitor);
 491
 492         pb_debug("%s: waiting on udev\n", __func__);
 493
 494         return udev;
 495
 496 fail:
 497         talloc_free(udev);
 498         return NULL;
 499 }
 500
 501 void udev_reinit(struct pb_udev *udev)
 502 {
 503         pb_log("udev: reinit requested, starting enumeration\n");
 504         udev_enumerate(udev->udev);
 505 }