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