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