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         udev_monitor_unref(udev->monitor);
  45         udev->monitor = NULL;
  46
  47         udev_unref(udev->udev);
  48         udev->udev = NULL;
  49
  50         return 0;
  51 }
  52
  53 static void udev_setup_device_params(struct udev_device *udev,
  54                 struct discover_device *dev)
  55 {
  56         struct udev_list_entry *list, *entry;
  57
  58         list = udev_device_get_properties_list_entry(udev);
  59         if (!list)
  60                 return;
  61
  62         udev_list_entry_foreach(entry, list)
  63                 discover_device_set_param(dev,
  64                                 udev_list_entry_get_name(entry),
  65                                 udev_list_entry_get_value(entry));
  66 }
  67
  68 static int udev_handle_block_add(struct pb_udev *udev, struct udev_device *dev,
  69                 const char *name)
  70 {
  71         struct discover_device *ddev;
  72         const char *typestr;
  73         const char *uuid;
  74         const char *path;
  75         const char *node;
  76         const char *prop;
  77         const char *type;
  78         bool cdrom;
  79
  80         typestr = udev_device_get_devtype(dev);
  81         if (!typestr) {
  82                 pb_debug("udev_device_get_devtype failed\n");
  83                 return -1;
  84         }
  85
  86         if (!(!strcmp(typestr, "disk") || !strcmp(typestr, "partition"))) {
  87                 pb_log("SKIP %s: invalid type %s\n", name, typestr);
  88                 return 0;
  89         }
  90
  91         node = udev_device_get_devnode(dev);
  92         path = udev_device_get_devpath(dev);
  93         if (path && (strstr(path, "virtual/block/loop")
  94                         || strstr(path, "virtual/block/ram"))) {
  95                 pb_log("SKIP: %s: ignored (path=%s)\n", name, path);
  96                 return 0;
  97         }
  98
  99         cdrom = node && !!udev_device_get_property_value(dev, "ID_CDROM");
 100         if (cdrom) {
 101                 /* CDROMs require a little initialisation, to get
 102                  * petitboot-compatible tray behaviour */
 103                 cdrom_init(node);
 104                 if (!cdrom_media_present(node)) {
 105                         pb_log("SKIP: %s: no media present\n", name);
 106                         return 0;
 107                 }
 108         }
 109
 110         type = udev_device_get_property_value(dev, "ID_FS_TYPE");
 111         if (!type) {
 112                 pb_log("SKIP: %s: no ID_FS_TYPE property\n", name);
 113                 return 0;
 114         }
 115
 116         /* We may see multipath devices; they'll have the same uuid as an
 117          * existing device, so only parse the first. */
 118         uuid = udev_device_get_property_value(dev, "ID_FS_UUID");
 119         if (uuid) {
 120                 ddev = device_lookup_by_uuid(udev->handler, uuid);
 121                 if (ddev) {
 122                         pb_log("SKIP: %s UUID [%s] already present (as %s)\n",
 123                                         name, uuid, ddev->device->id);
 124                         return 0;
 125                 }
 126         }
 127
 128         ddev = discover_device_create(udev->handler, name);
 129
 130         ddev->device_path = talloc_strdup(ddev, node);
 131
 132         if (uuid)
 133                 ddev->uuid = talloc_strdup(ddev, uuid);
 134         prop = udev_device_get_property_value(dev, "ID_FS_LABEL");
 135         if (prop)
 136                 ddev->label = talloc_strdup(ddev, prop);
 137         ddev->device->type = cdrom ? DEVICE_TYPE_OPTICAL : DEVICE_TYPE_DISK;
 138
 139         udev_setup_device_params(dev, ddev);
 140
 141         device_handler_discover(udev->handler, ddev);
 142
 143         return 0;
 144 }
 145
 146 static int udev_handle_dev_add(struct pb_udev *udev, struct udev_device *dev)
 147 {
 148         const char *subsys;
 149         const char *name;
 150
 151         name = udev_device_get_sysname(dev);
 152         if (!name) {
 153                 pb_debug("udev_device_get_sysname failed\n");
 154                 return -1;
 155         }
 156
 157         subsys = udev_device_get_subsystem(dev);
 158         if (!subsys) {
 159                 pb_debug("udev_device_get_subsystem failed\n");
 160                 return -1;
 161         }
 162
 163         if (device_lookup_by_id(udev->handler, name)) {
 164                 pb_debug("device %s is already present?\n", name);
 165                 return -1;
 166         }
 167
 168         if (!strcmp(subsys, "block")) {
 169                 return udev_handle_block_add(udev, dev, name);
 170         }
 171
 172         pb_log("SKIP %s: unknown subsystem %s\n", name, subsys);
 173         return -1;
 174 }
 175
 176
 177 static int udev_handle_dev_remove(struct pb_udev *udev, struct udev_device *dev)
 178 {
 179         struct discover_device *ddev;
 180         const char *name;
 181
 182         name = udev_device_get_sysname(dev);
 183         if (!name) {
 184                 pb_debug("udev_device_get_sysname failed\n");
 185                 return -1;
 186         }
 187
 188         ddev = device_lookup_by_id(udev->handler, name);
 189         if (!ddev)
 190                 return 0;
 191
 192         device_handler_remove(udev->handler, ddev);
 193
 194         return 0;
 195 }
 196
 197 /* returns true if further event processing should stop (eg., we've
 198  * ejected the cdrom)
 199  */
 200 static bool udev_handle_cdrom_events(struct pb_udev *udev,
 201                 struct udev_device *dev, struct discover_device *ddev)
 202 {
 203         const char *node;
 204
 205         node = udev_device_get_devnode(dev);
 206
 207         /* handle CDROM eject requests */
 208         if (udev_device_get_property_value(dev, "DISK_EJECT_REQUEST")) {
 209                 bool eject = false;
 210
 211                 pb_debug("udev: eject request\n");
 212
 213                 /* If the device is mounted, cdrom_id's own eject request may
 214                  * have failed. So, we'll need to do our own here.
 215                  */
 216                 if (ddev) {
 217                         eject = ddev->mounted;
 218                         udev_handle_dev_remove(udev, dev);
 219                         return false;
 220                 }
 221
 222                 if (eject)
 223                         cdrom_eject(node);
 224
 225                 return true;
 226         }
 227
 228         if (udev_device_get_property_value(dev, "DISK_MEDIA_CHANGE")) {
 229                 if (cdrom_media_present(node))
 230                         udev_handle_dev_add(udev, dev);
 231                 else
 232                         udev_handle_dev_remove(udev, dev);
 233                 return true;
 234         }
 235
 236         return false;
 237 }
 238
 239 static int udev_handle_dev_change(struct pb_udev *udev, struct udev_device *dev)
 240 {
 241         struct discover_device *ddev;
 242         const char *name;
 243         int rc = 0;
 244
 245         name = udev_device_get_sysname(dev);
 246
 247         ddev = device_lookup_by_id(udev->handler, name);
 248
 249         /* if this is a CDROM device, process eject & media change requests;
 250          * these may stop further processing */
 251         if (!udev_device_get_property_value(dev, "ID_CDROM")) {
 252                 if (udev_handle_cdrom_events(udev, dev, ddev))
 253                         return 0;
 254         }
 255
 256         /* if this is a new device, treat it as an add */
 257         if (!ddev)
 258                 rc = udev_handle_dev_add(udev, dev);
 259
 260         return rc;
 261 }
 262
 263 static int udev_handle_dev_action(struct udev_device *dev, const char *action)
 264 {
 265         struct pb_udev *udev = udev_get_userdata(udev_device_get_udev(dev));
 266         struct udev_list_entry *list;
 267         const char *name;
 268
 269         list = udev_device_get_properties_list_entry(dev);
 270         name = udev_device_get_sysname(dev);
 271
 272         pb_debug("udev: action %s, device %s\n", action, name);
 273         pb_debug("udev: properties:\n");
 274
 275         for (; list; list = udev_list_entry_get_next(list))
 276                 pb_debug("\t%-20s: %s\n", udev_list_entry_get_name(list),
 277                                 udev_list_entry_get_value(list));
 278
 279         if (!strcmp(action, "add"))
 280                 return udev_handle_dev_add(udev, dev);
 281
 282         else if (!strcmp(action, "remove"))
 283                 return udev_handle_dev_remove(udev, dev);
 284
 285         else if (!strcmp(action, "change"))
 286                 return udev_handle_dev_change(udev, dev);
 287
 288         return 0;
 289 }
 290
 291 static int udev_enumerate(struct udev *udev)
 292 {
 293         int result;
 294         struct udev_list_entry *list, *entry;
 295         struct udev_enumerate *enumerate;
 296
 297         enumerate = udev_enumerate_new(udev);
 298
 299         if (!enumerate) {
 300                 pb_log("udev_enumerate_new failed\n");
 301                 return -1;
 302         }
 303
 304         result = udev_enumerate_add_match_subsystem(enumerate, "block");
 305         if (result) {
 306                 pb_log("udev_enumerate_add_match_subsystem failed\n");
 307                 goto fail;
 308         }
 309
 310         result = udev_enumerate_add_match_is_initialized(enumerate);
 311         if (result) {
 312                 pb_log("udev_enumerate_add_match_is_initialised failed\n");
 313                 goto fail;
 314         }
 315
 316         udev_enumerate_scan_devices(enumerate);
 317
 318         list = udev_enumerate_get_list_entry(enumerate);
 319
 320         if (!list) {
 321                 pb_log("udev_enumerate_get_list_entry failed\n");
 322                 goto fail;
 323         }
 324
 325         udev_list_entry_foreach(entry, list) {
 326                 const char *syspath;
 327                 struct udev_device *dev;
 328
 329                 syspath = udev_list_entry_get_name(entry);
 330                 dev = udev_device_new_from_syspath(udev, syspath);
 331
 332                 udev_handle_dev_action(dev, "add");
 333
 334                 udev_device_unref(dev);
 335         }
 336
 337         udev_enumerate_unref(enumerate);
 338         return 0;
 339
 340 fail:
 341         udev_enumerate_unref(enumerate);
 342         return -1;
 343 }
 344
 345 static int udev_setup_monitor(struct udev *udev, struct udev_monitor **monitor)
 346 {
 347         int result;
 348         struct udev_monitor *m;
 349
 350         *monitor = NULL;
 351         m = udev_monitor_new_from_netlink(udev, "udev");
 352
 353         if (!m) {
 354                 pb_log("udev_monitor_new_from_netlink failed\n");
 355                 goto out_err;
 356         }
 357
 358         result = udev_monitor_set_receive_buffer_size(m, monitor_bufsize);
 359         if (result) {
 360                 pb_log("udev_monitor_set_rx_bufsize(%d) failed\n",
 361                         monitor_bufsize);
 362         }
 363
 364         result = udev_monitor_filter_add_match_subsystem_devtype(m, "block",
 365                 NULL);
 366
 367         if (result) {
 368                 pb_log("udev_monitor_filter_add_match_subsystem_devtype failed\n");
 369                 goto out_err;
 370         }
 371
 372         result = udev_monitor_enable_receiving(m);
 373
 374         if (result) {
 375                 pb_log("udev_monitor_enable_receiving failed\n");
 376                 goto out_err;
 377         }
 378
 379         *monitor = m;
 380         return 0;
 381
 382 out_err:
 383         udev_monitor_unref(m);
 384         return -1;
 385 }
 386
 387 /*
 388  * udev_process - waiter callback for monitor netlink.
 389  */
 390
 391 static int udev_process(void *arg)
 392 {
 393         struct udev_monitor *monitor = arg;
 394         struct udev_device *dev;
 395         const char *action;
 396
 397         dev = udev_monitor_receive_device(monitor);
 398         if (!dev) {
 399                 pb_log("udev_monitor_receive_device failed\n");
 400                 return -1;
 401         }
 402
 403         action = udev_device_get_action(dev);
 404
 405         if (!action) {
 406                 pb_log("udev_device_get_action failed\n");
 407         } else {
 408                 udev_handle_dev_action(dev, action);
 409         }
 410
 411         udev_device_unref(dev);
 412         return 0;
 413 }
 414
 415 static void udev_log_fn(struct udev __attribute__((unused)) *udev,
 416         int __attribute__((unused)) priority, const char *file, int line,
 417         const char *fn, const char *format, va_list args)
 418 {
 419       pb_log("libudev: %s %s:%d: ", fn, file, line);
 420       vfprintf(pb_log_get_stream(), format, args);
 421 }
 422
 423 struct pb_udev *udev_init(struct device_handler *handler,
 424                 struct waitset *waitset)
 425 {
 426         struct pb_udev *udev;
 427         int result;
 428
 429         udev = talloc(handler, struct pb_udev);
 430         talloc_set_destructor(udev, udev_destructor);
 431         udev->handler = handler;
 432
 433         udev->udev = udev_new();
 434
 435         if (!udev->udev) {
 436                 pb_log("udev_new failed\n");
 437                 goto fail_new;
 438         }
 439
 440         udev_set_userdata(udev->udev, udev);
 441
 442         udev_set_log_fn(udev->udev, udev_log_fn);
 443
 444         result = udev_setup_monitor(udev->udev, &udev->monitor);
 445         if (result)
 446                 goto fail_monitor;
 447
 448         result = udev_enumerate(udev->udev);
 449         if (result)
 450                 goto fail_enumerate;
 451
 452         waiter_register_io(waitset, udev_monitor_get_fd(udev->monitor), WAIT_IN,
 453                 udev_process, udev->monitor);
 454
 455         pb_debug("%s: waiting on udev\n", __func__);
 456
 457         return udev;
 458
 459 fail_monitor:
 460         udev_monitor_unref(udev->monitor);
 461 fail_enumerate:
 462         udev_unref(udev->udev);
 463 fail_new:
 464         talloc_free(udev);
 465         return NULL;
 466 }
 467
 468 void udev_reinit(struct pb_udev *udev)
 469 {
 470         pb_log("udev: reinit requested, starting enumeration\n");
 471         udev_enumerate(udev->udev);
 472 }