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