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 #include <url/url.h>
  16
  17 #include "device-handler.h"
  18 #include "discover-server.h"
  19 #include "event.h"
  20 #include "parser.h"
  21 #include "resource.h"
  22 #include "udev.h"
  23 #include "paths.h"
  24 #include "boot.h"
  25
  26 struct device_handler {
  27         struct discover_server  *server;
  28         int                     dry_run;
  29
  30         struct discover_device  **devices;
  31         unsigned int            n_devices;
  32
  33         struct list             unresolved_boot_options;
  34 };
  35
  36 static bool resource_is_resolved(struct resource *res)
  37 {
  38         return !res || res->resolved;
  39 }
  40
  41 /* We only use this in an assert, which will disappear if we're compiling
  42  * with NDEBUG, so we need the 'used' attribute for these builds */
  43 static bool __attribute__((used)) boot_option_is_resolved(
  44                 struct discover_boot_option *opt)
  45 {
  46         return resource_is_resolved(opt->boot_image) &&
  47                 resource_is_resolved(opt->initrd) &&
  48                 resource_is_resolved(opt->icon);
  49 }
  50
  51 static bool resource_resolve(struct resource *res, struct parser *parser,
  52                 struct device_handler *handler)
  53 {
  54         if (resource_is_resolved(res))
  55                 return true;
  56
  57         parser->resolve_resource(handler, res);
  58
  59         return res->resolved;
  60 }
  61
  62 static bool boot_option_resolve(struct discover_boot_option *opt,
  63                 struct device_handler *handler)
  64 {
  65         return resource_resolve(opt->boot_image, opt->source, handler) &&
  66                 resource_resolve(opt->initrd, opt->source, handler) &&
  67                 resource_resolve(opt->icon, opt->source, handler);
  68 }
  69
  70 static void boot_option_finalise(struct discover_boot_option *opt)
  71 {
  72         assert(boot_option_is_resolved(opt));
  73
  74         /* check that the parsers haven't set any of the final data */
  75         assert(!opt->option->boot_image_file);
  76         assert(!opt->option->initrd_file);
  77         assert(!opt->option->icon_file);
  78
  79         if (opt->boot_image)
  80                 opt->option->boot_image_file = opt->boot_image->url->full;
  81         if (opt->initrd)
  82                 opt->option->initrd_file = opt->initrd->url->full;
  83         if (opt->icon)
  84                 opt->option->icon_file = opt->icon->url->full;
  85 }
  86
  87 static void process_boot_option_queue(struct device_handler *handler)
  88 {
  89         struct discover_boot_option *opt, *tmp;
  90
  91         list_for_each_entry_safe(&handler->unresolved_boot_options,
  92                         opt, tmp, list) {
  93
  94                 if (!boot_option_resolve(opt, handler))
  95                         continue;
  96
  97                 list_remove(&opt->list);
  98                 list_add(&opt->device->boot_options, &opt->list);
  99                 talloc_steal(opt->device, opt);
 100                 boot_option_finalise(opt);
 101                 discover_server_notify_boot_option_add(handler->server,
 102                                                         opt->option);
 103         }
 104 }
 105
 106 /**
 107  * context_commit - Commit a temporary discovery context to the handler,
 108  * and notify the clients about any new options / devices
 109  */
 110 static void context_commit(struct device_handler *handler,
 111                 struct discover_context *ctx)
 112 {
 113         struct discover_device *dev = ctx->device;
 114         struct discover_boot_option *opt, *tmp;
 115         unsigned int i, existing_device = 0;
 116
 117         /* do we already have this device? */
 118         for (i = 0; i < handler->n_devices; i++) {
 119                 if (ctx->device == handler->devices[i]) {
 120                         existing_device = 1;
 121                         break;
 122                 }
 123         }
 124
 125         /* if not already present, add the device to the handler's array */
 126         if (!existing_device) {
 127                 handler->n_devices++;
 128                 handler->devices = talloc_realloc(handler, handler->devices,
 129                         struct discover_device *, handler->n_devices);
 130                 handler->devices[handler->n_devices - 1] = dev;
 131                 talloc_steal(handler, dev);
 132
 133                 discover_server_notify_device_add(handler->server, dev->device);
 134
 135                 /* this new device might be able to resolve existing boot
 136                  * options */
 137                 process_boot_option_queue(handler);
 138         }
 139
 140
 141         /* move boot options from the context to the device */
 142         list_for_each_entry_safe(&ctx->boot_options, opt, tmp, list) {
 143                 list_remove(&opt->list);
 144
 145                 if (boot_option_resolve(opt, handler)) {
 146                         list_add(&dev->boot_options, &opt->list);
 147                         talloc_steal(dev, opt);
 148                         boot_option_finalise(opt);
 149                         discover_server_notify_boot_option_add(handler->server,
 150                                                                 opt->option);
 151                 } else {
 152                         list_add(&handler->unresolved_boot_options, &opt->list);
 153                         talloc_steal(handler, opt);
 154                 }
 155         }
 156 }
 157
 158 void discover_context_add_boot_option(struct discover_context *ctx,
 159                 struct discover_boot_option *boot_option)
 160 {
 161         boot_option->source = ctx->parser;
 162         list_add(&ctx->boot_options, &boot_option->list);
 163         talloc_steal(ctx, boot_option);
 164 }
 165
 166 /**
 167  * device_handler_remove - Remove a device from the handler device array.
 168  */
 169
 170 static void device_handler_remove(struct device_handler *handler,
 171         struct discover_device *device)
 172 {
 173         unsigned int i;
 174
 175         for (i = 0; i < handler->n_devices; i++)
 176                 if (handler->devices[i] == device)
 177                         break;
 178
 179         if (i == handler->n_devices) {
 180                 assert(0 && "unknown device");
 181                 return;
 182         }
 183
 184         handler->n_devices--;
 185         memmove(&handler->devices[i], &handler->devices[i + 1],
 186                 (handler->n_devices - i) * sizeof(handler->devices[0]));
 187         handler->devices = talloc_realloc(handler, handler->devices,
 188                 struct discover_device *, handler->n_devices);
 189
 190         discover_server_notify_device_remove(handler->server, device->device);
 191
 192         talloc_free(device);
 193 }
 194
 195 /**
 196  * device_handler_get_device_count - Get the count of current handler devices.
 197  */
 198
 199 int device_handler_get_device_count(const struct device_handler *handler)
 200 {
 201         return handler->n_devices;
 202 }
 203
 204 /**
 205  * device_handler_get_device - Get a handler device by index.
 206  */
 207
 208 const struct discover_device *device_handler_get_device(
 209         const struct device_handler *handler, unsigned int index)
 210 {
 211         if (index >= handler->n_devices) {
 212                 assert(0 && "bad index");
 213                 return NULL;
 214         }
 215
 216         return handler->devices[index];
 217 }
 218
 219 static int mount_device(struct discover_device *dev)
 220 {
 221         const char *argv[6];
 222
 223         if (!dev->mount_path)
 224                 dev->mount_path = join_paths(dev, mount_base(),
 225                                                 dev->device_path);
 226
 227         if (pb_mkdir_recursive(dev->mount_path))
 228                 pb_log("couldn't create mount directory %s: %s\n",
 229                                 dev->mount_path, strerror(errno));
 230
 231         argv[0] = pb_system_apps.mount;
 232         argv[1] = dev->device_path;
 233         argv[2] = dev->mount_path;
 234         argv[3] = "-o";
 235         argv[4] = "ro";
 236         argv[5] = NULL;
 237
 238         if (pb_run_cmd(argv, 1, 0)) {
 239
 240                 /* Retry mount without ro option. */
 241
 242                 argv[0] = pb_system_apps.mount;
 243                 argv[1] = dev->device_path;
 244                 argv[2] = dev->mount_path;
 245                 argv[3] = NULL;
 246
 247                 if (pb_run_cmd(argv, 1, 0))
 248                         goto out_rmdir;
 249         }
 250
 251         return 0;
 252
 253 out_rmdir:
 254         pb_rmdir_recursive(mount_base(), dev->mount_path);
 255         return -1;
 256 }
 257
 258 static int umount_device(struct discover_device *dev)
 259 {
 260         int status;
 261         pid_t pid;
 262
 263         if (!dev->mount_path)
 264                 return 0;
 265
 266         pid = fork();
 267         if (pid == -1) {
 268                 pb_log("%s: fork failed: %s\n", __func__, strerror(errno));
 269                 return -1;
 270         }
 271
 272         if (pid == 0) {
 273                 execl(pb_system_apps.umount, pb_system_apps.umount,
 274                                                 dev->mount_path, NULL);
 275                 exit(EXIT_FAILURE);
 276         }
 277
 278         if (waitpid(pid, &status, 0) == -1) {
 279                 pb_log("%s: waitpid failed: %s\n", __func__,
 280                                 strerror(errno));
 281                 return -1;
 282         }
 283
 284         if (!WIFEXITED(status) || WEXITSTATUS(status) != 0)
 285                 return -1;
 286
 287         pb_rmdir_recursive(mount_base(), dev->mount_path);
 288
 289         return 0;
 290 }
 291
 292 static struct discover_device *find_device(struct device_handler *handler,
 293                 const char *id)
 294 {
 295         struct discover_device *dev;
 296         unsigned int i;
 297
 298         for (i = 0; i < handler->n_devices; i++) {
 299                 dev = handler->devices[i];
 300                 if (!strcmp(dev->device->id, id))
 301                         return dev;
 302         }
 303
 304         return NULL;
 305 }
 306
 307 static int destroy_device(void *arg)
 308 {
 309         struct discover_device *dev = arg;
 310
 311         umount_device(dev);
 312
 313         return 0;
 314 }
 315
 316 static struct discover_device *discover_device_create(
 317                 struct device_handler *handler,
 318                 struct discover_context *ctx,
 319                 struct event *event)
 320 {
 321         struct discover_device *dev;
 322         const char *devname;
 323
 324         dev = find_device(handler, event->device);
 325         if (dev)
 326                 return dev;
 327
 328         dev = talloc_zero(ctx, struct discover_device);
 329         dev->device = talloc_zero(dev, struct device);
 330         list_init(&dev->boot_options);
 331
 332         devname = event_get_param(ctx->event, "DEVNAME");
 333         if (devname)
 334                 dev->device_path = talloc_strdup(dev, devname);
 335
 336         dev->device->id = talloc_strdup(dev, event->device);
 337
 338         talloc_set_destructor(dev, destroy_device);
 339
 340         return dev;
 341 }
 342
 343 struct discover_boot_option *discover_boot_option_create(
 344                 struct discover_context *ctx,
 345                 struct discover_device *device)
 346 {
 347         struct discover_boot_option *opt;
 348
 349         opt = talloc_zero(ctx, struct discover_boot_option);
 350         opt->option = talloc_zero(opt, struct boot_option);
 351         opt->device = device;
 352
 353         return opt;
 354 }
 355
 356
 357 static int handle_add_udev_event(struct device_handler *handler,
 358                 struct event *event)
 359 {
 360         struct discover_context *ctx;
 361         struct discover_device *dev;
 362         const char *param;
 363         int rc;
 364
 365         /* create our context */
 366         ctx = talloc(handler, struct discover_context);
 367         ctx->event = event;
 368         list_init(&ctx->boot_options);
 369
 370         /* create our top-level device */
 371         dev = discover_device_create(handler, ctx, event);
 372
 373         ctx->device = dev;
 374
 375         /* try to parse UUID and labels */
 376         param = event_get_param(ctx->event, "ID_FS_UUID");
 377         if (param)
 378                 dev->uuid = talloc_strdup(dev, param);
 379
 380         param = event_get_param(ctx->event, "ID_FS_LABEL");
 381         if (param)
 382                 dev->label = talloc_strdup(dev, param);
 383
 384         rc = mount_device(dev);
 385         if (rc) {
 386                 talloc_free(ctx);
 387                 return 0;
 388         }
 389
 390         /* run the parsers. This will populate the ctx's boot_option list. */
 391         iterate_parsers(ctx);
 392
 393         /* add discovered stuff to the handler */
 394         context_commit(handler, ctx);
 395
 396         talloc_free(ctx);
 397
 398         return 0;
 399 }
 400
 401 static int handle_remove_udev_event(struct device_handler *handler,
 402                 struct event *event)
 403 {
 404         struct discover_device *dev;
 405
 406         dev = find_device(handler, event->device);
 407         if (!dev)
 408                 return 0;
 409
 410         /* remove device from handler device array */
 411         device_handler_remove(handler, dev);
 412
 413         return 0;
 414 }
 415
 416 static int handle_add_user_event(struct device_handler *handler,
 417                 struct event *event)
 418 {
 419         struct discover_context *ctx;
 420         struct discover_device *dev;
 421         int rc;
 422
 423         assert(event->device);
 424
 425         ctx = talloc(handler, struct discover_context);
 426         ctx->event = event;
 427         list_init(&ctx->boot_options);
 428
 429         dev = discover_device_create(handler, ctx, event);
 430         ctx->device = dev;
 431
 432         rc = parse_user_event(ctx, event);
 433
 434         if (!rc)
 435                 context_commit(handler, ctx);
 436
 437         return rc;
 438 }
 439
 440 static int handle_remove_user_event(struct device_handler *handler,
 441                 struct event *event)
 442 {
 443         struct discover_device *dev = find_device(handler, event->device);
 444
 445         if (!dev)
 446                 return 0;
 447
 448         /* remove device from handler device array */
 449         device_handler_remove(handler, dev);
 450
 451         return 0;
 452 }
 453
 454 typedef int (*event_handler)(struct device_handler *, struct event *);
 455
 456 static event_handler handlers[EVENT_TYPE_MAX][EVENT_ACTION_MAX] = {
 457         [EVENT_TYPE_UDEV] = {
 458                 [EVENT_ACTION_ADD]      = handle_add_udev_event,
 459                 [EVENT_ACTION_REMOVE]   = handle_remove_udev_event,
 460         },
 461         [EVENT_TYPE_USER] = {
 462                 [EVENT_ACTION_ADD]      = handle_add_user_event,
 463                 [EVENT_ACTION_REMOVE]   = handle_remove_user_event,
 464         }
 465 };
 466
 467 int device_handler_event(struct device_handler *handler,
 468                 struct event *event)
 469 {
 470         if (event->type >= EVENT_TYPE_MAX ||
 471                         event->action >= EVENT_ACTION_MAX ||
 472                         !handlers[event->type][event->action]) {
 473                 pb_log("%s unknown type/action: %d/%d\n", __func__,
 474                                 event->type, event->action);
 475                 return 0;
 476         }
 477
 478         return handlers[event->type][event->action](handler, event);
 479 }
 480
 481 struct device_handler *device_handler_init(struct discover_server *server,
 482                 int dry_run)
 483 {
 484         struct device_handler *handler;
 485
 486         handler = talloc(NULL, struct device_handler);
 487         handler->devices = NULL;
 488         handler->n_devices = 0;
 489         handler->server = server;
 490         handler->dry_run = dry_run;
 491         list_init(&handler->unresolved_boot_options);
 492
 493         /* set up our mount point base */
 494         pb_mkdir_recursive(mount_base());
 495
 496         parser_init();
 497
 498         return handler;
 499 }
 500
 501 void device_handler_destroy(struct device_handler *handler)
 502 {
 503         talloc_free(handler);
 504 }
 505
 506 static int device_match_path(struct discover_device *dev, const char *path)
 507 {
 508         return !strcmp(dev->device_path, path);
 509 }
 510
 511 static int device_match_uuid(struct discover_device *dev, const char *uuid)
 512 {
 513         return dev->uuid && !strcmp(dev->uuid, uuid);
 514 }
 515
 516 static int device_match_label(struct discover_device *dev, const char *label)
 517 {
 518         return dev->label && !strcmp(dev->label, label);
 519 }
 520
 521 static int device_match_id(struct discover_device *dev, const char *id)
 522 {
 523         return !strcmp(dev->device->id, id);
 524 }
 525
 526 static struct discover_device *device_lookup(
 527                 struct device_handler *device_handler,
 528                 int (match_fn)(struct discover_device *, const char *),
 529                 const char *str)
 530 {
 531         struct discover_device *dev;
 532         unsigned int i;
 533
 534         if (!str)
 535                 return NULL;
 536
 537         for (i = 0; i < device_handler->n_devices; i++) {
 538                 dev = device_handler->devices[i];
 539
 540                 if (match_fn(dev, str))
 541                         return dev;
 542         }
 543
 544         return NULL;
 545 }
 546
 547 struct discover_device *device_lookup_by_name(struct device_handler *handler,
 548                 const char *name)
 549 {
 550         struct discover_device *dev;
 551         char *path;
 552
 553         if (strncmp(name, "/dev/", strlen("/dev/")))
 554                 path = talloc_asprintf(NULL, "/dev/%s", name);
 555         else
 556                 path = talloc_strdup(NULL, name);
 557
 558         dev = device_lookup_by_path(handler, path);
 559
 560         talloc_free(path);
 561
 562         return dev;
 563 }
 564
 565 struct discover_device *device_lookup_by_path(
 566                 struct device_handler *device_handler,
 567                 const char *path)
 568 {
 569         return device_lookup(device_handler, device_match_path, path);
 570 }
 571
 572 struct discover_device *device_lookup_by_uuid(
 573                 struct device_handler *device_handler,
 574                 const char *uuid)
 575 {
 576         return device_lookup(device_handler, device_match_uuid, uuid);
 577 }
 578
 579 struct discover_device *device_lookup_by_label(
 580                 struct device_handler *device_handler,
 581                 const char *label)
 582 {
 583         return device_lookup(device_handler, device_match_label, label);
 584 }
 585
 586 struct discover_device *device_lookup_by_id(
 587                 struct device_handler *device_handler,
 588                 const char *id)
 589 {
 590         return device_lookup(device_handler, device_match_id, id);
 591 }
 592
 593 static struct discover_boot_option *find_boot_option_by_id(
 594                 struct device_handler *handler, const char *id)
 595 {
 596         unsigned int i;
 597
 598         for (i = 0; i < handler->n_devices; i++) {
 599                 struct discover_device *dev = handler->devices[i];
 600                 struct discover_boot_option *opt;
 601
 602                 list_for_each_entry(&dev->boot_options, opt, list)
 603                         if (!strcmp(opt->option->id, id))
 604                                 return opt;
 605         }
 606
 607         return NULL;
 608 }
 609
 610 void device_handler_boot(struct device_handler *handler,
 611                 struct boot_command *cmd)
 612 {
 613         struct discover_boot_option *opt;
 614
 615         opt = find_boot_option_by_id(handler, cmd->option_id);
 616
 617         boot(handler, opt, cmd, handler->dry_run);
 618 }