git.ozlabs.org Git - petitboot/blob - discover/device-handler.c

   1
   2 #include <assert.h>
   3 #include <stdlib.h>
   4 #include <unistd.h>
   5 #include <string.h>
   6 #include <errno.h>
   7 #include <sys/stat.h>
   8 #include <sys/wait.h>
   9
  10 #include <talloc/talloc.h>
  11 #include <list/list.h>
  12 #include <log/log.h>
  13 #include <types/types.h>
  14 #include <system/system.h>
  15
  16 #include "device-handler.h"
  17 #include "discover-server.h"
  18 #include "event.h"
  19 #include "parser.h"
  20 #include "udev.h"
  21 #include "paths.h"
  22 #include "boot.h"
  23
  24 struct device_handler {
  25         struct discover_server  *server;
  26         int                     dry_run;
  27
  28         struct discover_device  **devices;
  29         unsigned int            n_devices;
  30 };
  31
  32 /**
  33  * context_commit - Commit a temporary discovery context to the handler,
  34  * and notify the clients about any new options / devices
  35  */
  36 static void context_commit(struct device_handler *handler,
  37                 struct discover_context *ctx)
  38 {
  39         struct discover_device *dev = ctx->device;
  40         struct discover_boot_option *opt, *tmp;
  41         unsigned int i, existing_device;
  42
  43         /* do we already have this device? */
  44         for (i = 0; i < handler->n_devices; i++) {
  45                 if (ctx->device == handler->devices[i]) {
  46                         existing_device = 1;
  47                         break;
  48                 }
  49         }
  50
  51         /* if not already present, add the device to the handler's array */
  52         if (!existing_device) {
  53                 handler->n_devices++;
  54                 handler->devices = talloc_realloc(handler, handler->devices,
  55                         struct discover_device *, handler->n_devices);
  56                 handler->devices[handler->n_devices - 1] = dev;
  57                 talloc_steal(handler, dev);
  58
  59                 discover_server_notify_device_add(handler->server, dev->device);
  60         }
  61
  62
  63         /* move boot options from the context to the device */
  64         list_for_each_entry_safe(&ctx->boot_options, opt, tmp, list) {
  65                 list_remove(&opt->list);
  66                 list_add(&dev->boot_options, &opt->list);
  67                 talloc_steal(dev, opt);
  68                 discover_server_notify_boot_option_add(handler->server,
  69                                                         opt->option);
  70         }
  71 }
  72
  73 void discover_context_add_boot_option(struct discover_context *ctx,
  74                 struct discover_boot_option *boot_option)
  75 {
  76         list_add(&ctx->boot_options, &boot_option->list);
  77         talloc_steal(ctx, boot_option);
  78 }
  79
  80 /**
  81  * device_handler_remove - Remove a device from the handler device array.
  82  */
  83
  84 static void device_handler_remove(struct device_handler *handler,
  85         struct discover_device *device)
  86 {
  87         unsigned int i;
  88
  89         for (i = 0; i < handler->n_devices; i++)
  90                 if (handler->devices[i] == device)
  91                         break;
  92
  93         if (i == handler->n_devices) {
  94                 assert(0 && "unknown device");
  95                 return;
  96         }
  97
  98         handler->n_devices--;
  99         memmove(&handler->devices[i], &handler->devices[i + 1],
 100                 (handler->n_devices - i) * sizeof(handler->devices[0]));
 101         handler->devices = talloc_realloc(handler, handler->devices,
 102                 struct discover_device *, handler->n_devices);
 103
 104         discover_server_notify_device_remove(handler->server, device->device);
 105
 106         talloc_free(device);
 107 }
 108
 109 /**
 110  * device_handler_get_device_count - Get the count of current handler devices.
 111  */
 112
 113 int device_handler_get_device_count(const struct device_handler *handler)
 114 {
 115         return handler->n_devices;
 116 }
 117
 118 /**
 119  * device_handler_get_device - Get a handler device by index.
 120  */
 121
 122 const struct discover_device *device_handler_get_device(
 123         const struct device_handler *handler, unsigned int index)
 124 {
 125         if (index >= handler->n_devices) {
 126                 assert(0 && "bad index");
 127                 return NULL;
 128         }
 129
 130         return handler->devices[index];
 131 }
 132
 133 static void setup_device_links(struct discover_device *dev)
 134 {
 135         struct link {
 136                 const char *dir, *val;
 137         } *link, links[] = {
 138                 {
 139                         .dir = "disk/by-uuid",
 140                         .val = dev->uuid,
 141                 },
 142                 {
 143                         .dir = "disk/by-label",
 144                         .val = dev->label,
 145                 },
 146                 {
 147                         .dir = NULL
 148                 }
 149         };
 150
 151         for (link = links; link->dir; link++) {
 152                 char *enc, *dir, *path;
 153
 154                 if (!link->val || !*link->val)
 155                         continue;
 156
 157                 enc = encode_label(dev, link->val);
 158                 dir = join_paths(dev, mount_base(), link->dir);
 159                 path = join_paths(dev, dir, enc);
 160
 161                 if (!pb_mkdir_recursive(dir)) {
 162                         unlink(path);
 163                         if (symlink(dev->mount_path, path)) {
 164                                 pb_log("symlink(%s,%s): %s\n",
 165                                                 dev->mount_path, path,
 166                                                 strerror(errno));
 167                                 talloc_free(path);
 168                         } else {
 169                                 int i = dev->n_links++;
 170                                 dev->links = talloc_realloc(dev,
 171                                                 dev->links, char *,
 172                                                 dev->n_links);
 173                                 dev->links[i] = path;
 174                         }
 175
 176                 }
 177
 178                 talloc_free(dir);
 179                 talloc_free(enc);
 180         }
 181 }
 182
 183 static void remove_device_links(struct discover_device *dev)
 184 {
 185         int i;
 186
 187         for (i = 0; i < dev->n_links; i++)
 188                 unlink(dev->links[i]);
 189 }
 190
 191 static int mount_device(struct discover_device *dev)
 192 {
 193         const char *mountpoint;
 194         const char *argv[6];
 195
 196         if (!dev->mount_path) {
 197                 mountpoint = mountpoint_for_device(dev->device_path);
 198                 dev->mount_path = talloc_strdup(dev, mountpoint);
 199         }
 200
 201         if (pb_mkdir_recursive(dev->mount_path))
 202                 pb_log("couldn't create mount directory %s: %s\n",
 203                                 dev->mount_path, strerror(errno));
 204
 205         argv[0] = pb_system_apps.mount;
 206         argv[1] = dev->device_path;
 207         argv[2] = dev->mount_path;
 208         argv[3] = "-o";
 209         argv[4] = "ro";
 210         argv[5] = NULL;
 211
 212         if (pb_run_cmd(argv, 1, 0)) {
 213
 214                 /* Retry mount without ro option. */
 215
 216                 argv[0] = pb_system_apps.mount;
 217                 argv[1] = dev->device_path;
 218                 argv[2] = dev->mount_path;
 219                 argv[3] = NULL;
 220
 221                 if (pb_run_cmd(argv, 1, 0))
 222                         goto out_rmdir;
 223         }
 224
 225         setup_device_links(dev);
 226         return 0;
 227
 228 out_rmdir:
 229         pb_rmdir_recursive(mount_base(), dev->mount_path);
 230         return -1;
 231 }
 232
 233 static int umount_device(struct discover_device *dev)
 234 {
 235         int status;
 236         pid_t pid;
 237
 238         remove_device_links(dev);
 239
 240         if (!dev->mount_path)
 241                 return 0;
 242
 243         pid = fork();
 244         if (pid == -1) {
 245                 pb_log("%s: fork failed: %s\n", __func__, strerror(errno));
 246                 return -1;
 247         }
 248
 249         if (pid == 0) {
 250                 execl(pb_system_apps.umount, pb_system_apps.umount,
 251                                                 dev->mount_path, NULL);
 252                 exit(EXIT_FAILURE);
 253         }
 254
 255         if (waitpid(pid, &status, 0) == -1) {
 256                 pb_log("%s: waitpid failed: %s\n", __func__,
 257                                 strerror(errno));
 258                 return -1;
 259         }
 260
 261         if (!WIFEXITED(status) || WEXITSTATUS(status) != 0)
 262                 return -1;
 263
 264         pb_rmdir_recursive(mount_base(), dev->mount_path);
 265
 266         return 0;
 267 }
 268
 269 static struct discover_device *find_device(struct device_handler *handler,
 270                 const char *id)
 271 {
 272         struct discover_device *dev;
 273         unsigned int i;
 274
 275         for (i = 0; i < handler->n_devices; i++) {
 276                 dev = handler->devices[i];
 277                 if (!strcmp(dev->device->id, id))
 278                         return dev;
 279         }
 280
 281         return NULL;
 282 }
 283
 284 static int destroy_device(void *arg)
 285 {
 286         struct discover_device *dev = arg;
 287
 288         umount_device(dev);
 289
 290         return 0;
 291 }
 292
 293 static struct discover_device *discover_device_create(
 294                 struct device_handler *handler,
 295                 struct discover_context *ctx,
 296                 struct event *event)
 297 {
 298         struct discover_device *dev;
 299         const char *devname;
 300
 301         dev = find_device(handler, event->device);
 302         if (dev)
 303                 return dev;
 304
 305         dev = talloc_zero(ctx, struct discover_device);
 306         dev->device = talloc_zero(dev, struct device);
 307         list_init(&dev->boot_options);
 308
 309         devname = event_get_param(ctx->event, "DEVNAME");
 310         if (devname)
 311                 dev->device_path = talloc_strdup(dev, devname);
 312
 313         dev->device->id = talloc_strdup(dev, event->device);
 314
 315         talloc_set_destructor(dev, destroy_device);
 316
 317         return dev;
 318 }
 319
 320 struct discover_boot_option *discover_boot_option_create(
 321                 struct discover_context *ctx,
 322                 struct discover_device *device)
 323 {
 324         struct discover_boot_option *opt;
 325
 326         opt = talloc_zero(ctx, struct discover_boot_option);
 327         opt->option = talloc_zero(opt, struct boot_option);
 328         opt->device = device;
 329
 330         return opt;
 331 }
 332
 333
 334 static int handle_add_udev_event(struct device_handler *handler,
 335                 struct event *event)
 336 {
 337         struct discover_context *ctx;
 338         struct discover_device *dev;
 339         const char *param;
 340         int rc;
 341
 342         /* create our context */
 343         ctx = talloc(handler, struct discover_context);
 344         ctx->event = event;
 345         list_init(&ctx->boot_options);
 346
 347         /* create our top-level device */
 348         dev = discover_device_create(handler, ctx, event);
 349
 350         ctx->device = dev;
 351
 352         /* try to parse UUID and labels */
 353         param = event_get_param(ctx->event, "ID_FS_UUID");
 354         if (param)
 355                 dev->uuid = talloc_strdup(dev, param);
 356
 357         param = event_get_param(ctx->event, "ID_FS_LABEL");
 358         if (param)
 359                 dev->label = talloc_strdup(dev, param);
 360
 361         rc = mount_device(dev);
 362         if (rc) {
 363                 talloc_free(ctx);
 364                 return 0;
 365         }
 366
 367         /* run the parsers. This will populate the ctx's boot_option list. */
 368         iterate_parsers(ctx);
 369
 370         /* add discovered stuff to the handler */
 371         context_commit(handler, ctx);
 372
 373         talloc_free(ctx);
 374
 375         return 0;
 376 }
 377
 378 static int handle_remove_udev_event(struct device_handler *handler,
 379                 struct event *event)
 380 {
 381         struct discover_device *dev;
 382
 383         dev = find_device(handler, event->device);
 384         if (!dev)
 385                 return 0;
 386
 387         /* remove device from handler device array */
 388         device_handler_remove(handler, dev);
 389
 390         return 0;
 391 }
 392
 393 static int handle_add_user_event(struct device_handler *handler,
 394                 struct event *event)
 395 {
 396         struct discover_context *ctx;
 397         struct discover_device *dev;
 398         int rc;
 399
 400         assert(event->device);
 401
 402         ctx = talloc(handler, struct discover_context);
 403         ctx->event = event;
 404         list_init(&ctx->boot_options);
 405
 406         dev = discover_device_create(handler, ctx, event);
 407         ctx->device = dev;
 408
 409         rc = parse_user_event(ctx, event);
 410
 411         if (!rc)
 412                 context_commit(handler, ctx);
 413
 414         return rc;
 415 }
 416
 417 static int handle_remove_user_event(struct device_handler *handler,
 418                 struct event *event)
 419 {
 420         struct discover_device *dev = find_device(handler, event->device);
 421
 422         if (!dev)
 423                 return 0;
 424
 425         /* remove device from handler device array */
 426         device_handler_remove(handler, dev);
 427
 428         return 0;
 429 }
 430
 431 typedef int (*event_handler)(struct device_handler *, struct event *);
 432
 433 static event_handler handlers[EVENT_TYPE_MAX][EVENT_ACTION_MAX] = {
 434         [EVENT_TYPE_UDEV] = {
 435                 [EVENT_ACTION_ADD]      = handle_add_udev_event,
 436                 [EVENT_ACTION_REMOVE]   = handle_remove_udev_event,
 437         },
 438         [EVENT_TYPE_USER] = {
 439                 [EVENT_ACTION_ADD]      = handle_add_user_event,
 440                 [EVENT_ACTION_REMOVE]   = handle_remove_user_event,
 441         }
 442 };
 443
 444 int device_handler_event(struct device_handler *handler,
 445                 struct event *event)
 446 {
 447         if (event->type >= EVENT_TYPE_MAX ||
 448                         event->action >= EVENT_ACTION_MAX ||
 449                         !handlers[event->type][event->action]) {
 450                 pb_log("%s unknown type/action: %d/%d\n", __func__,
 451                                 event->type, event->action);
 452                 return 0;
 453         }
 454
 455         return handlers[event->type][event->action](handler, event);
 456 }
 457
 458 struct device_handler *device_handler_init(struct discover_server *server,
 459                 int dry_run)
 460 {
 461         struct device_handler *handler;
 462
 463         handler = talloc(NULL, struct device_handler);
 464         handler->devices = NULL;
 465         handler->n_devices = 0;
 466         handler->server = server;
 467         handler->dry_run = dry_run;
 468
 469         /* set up our mount point base */
 470         pb_mkdir_recursive(mount_base());
 471
 472         parser_init();
 473
 474         return handler;
 475 }
 476
 477 void device_handler_destroy(struct device_handler *handler)
 478 {
 479         talloc_free(handler);
 480 }
 481
 482 static int device_match_path(struct discover_device *dev, const char *path)
 483 {
 484         return !strcmp(dev->device_path, path);
 485 }
 486
 487 static int device_match_uuid(struct discover_device *dev, const char *uuid)
 488 {
 489         return dev->uuid && !strcmp(dev->uuid, uuid);
 490 }
 491
 492 static int device_match_label(struct discover_device *dev, const char *label)
 493 {
 494         return dev->label && !strcmp(dev->label, label);
 495 }
 496
 497 static int device_match_id(struct discover_device *dev, const char *id)
 498 {
 499         return !strcmp(dev->device->id, id);
 500 }
 501
 502 static struct discover_device *device_lookup(
 503                 struct device_handler *device_handler,
 504                 int (match_fn)(struct discover_device *, const char *),
 505                 const char *str)
 506 {
 507         struct discover_device *dev;
 508         unsigned int i;
 509
 510         if (!str)
 511                 return NULL;
 512
 513         for (i = 0; i < device_handler->n_devices; i++) {
 514                 dev = device_handler->devices[i];
 515
 516                 if (match_fn(dev, str))
 517                         return dev;
 518         }
 519
 520         return NULL;
 521 }
 522
 523 struct discover_device *device_lookup_by_name(struct device_handler *handler,
 524                 const char *name)
 525 {
 526         struct discover_device *dev;
 527         char *path;
 528
 529         if (strncmp(name, "/dev/", strlen("/dev/")))
 530                 path = talloc_asprintf(NULL, "/dev/%s", name);
 531         else
 532                 path = talloc_strdup(NULL, name);
 533
 534         dev = device_lookup_by_path(handler, path);
 535
 536         talloc_free(path);
 537
 538         return dev;
 539 }
 540
 541 struct discover_device *device_lookup_by_path(
 542                 struct device_handler *device_handler,
 543                 const char *path)
 544 {
 545         return device_lookup(device_handler, device_match_path, path);
 546 }
 547
 548 struct discover_device *device_lookup_by_uuid(
 549                 struct device_handler *device_handler,
 550                 const char *uuid)
 551 {
 552         return device_lookup(device_handler, device_match_uuid, uuid);
 553 }
 554
 555 struct discover_device *device_lookup_by_label(
 556                 struct device_handler *device_handler,
 557                 const char *label)
 558 {
 559         return device_lookup(device_handler, device_match_label, label);
 560 }
 561
 562 struct discover_device *device_lookup_by_id(
 563                 struct device_handler *device_handler,
 564                 const char *id)
 565 {
 566         return device_lookup(device_handler, device_match_id, id);
 567 }
 568
 569 static struct discover_boot_option *find_boot_option_by_id(
 570                 struct device_handler *handler, const char *id)
 571 {
 572         unsigned int i;
 573
 574         for (i = 0; i < handler->n_devices; i++) {
 575                 struct discover_device *dev = handler->devices[i];
 576                 struct discover_boot_option *opt;
 577
 578                 list_for_each_entry(&dev->boot_options, opt, list)
 579                         if (!strcmp(opt->option->id, id))
 580                                 return opt;
 581         }
 582
 583         return NULL;
 584 }
 585
 586 void device_handler_boot(struct device_handler *handler,
 587                 struct boot_command *cmd)
 588 {
 589         struct discover_boot_option *opt;
 590
 591         opt = find_boot_option_by_id(handler, cmd->option_id);
 592
 593         boot(handler, opt->option, cmd, handler->dry_run);
 594 }