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         unsigned int i, existing_device;
  41         struct boot_option *opt, *tmp;
  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->device->boot_options, &opt->list);
  67                 dev->device->n_options++;
  68                 discover_server_notify_boot_option_add(handler->server, opt);
  69         }
  70 }
  71
  72 void discover_context_add_boot_option(struct discover_context *ctx,
  73                 struct boot_option *boot_option)
  74 {
  75         list_add(&ctx->boot_options, &boot_option->list);
  76         talloc_steal(ctx, boot_option);
  77 }
  78
  79 /**
  80  * device_handler_remove - Remove a device from the handler device array.
  81  */
  82
  83 static void device_handler_remove(struct device_handler *handler,
  84         struct discover_device *device)
  85 {
  86         unsigned int i;
  87
  88         for (i = 0; i < handler->n_devices; i++)
  89                 if (handler->devices[i] == device)
  90                         break;
  91
  92         if (i == handler->n_devices) {
  93                 assert(0 && "unknown device");
  94                 return;
  95         }
  96
  97         handler->n_devices--;
  98         memmove(&handler->devices[i], &handler->devices[i + 1],
  99                 (handler->n_devices - i) * sizeof(handler->devices[0]));
 100         handler->devices = talloc_realloc(handler, handler->devices,
 101                 struct discover_device *, handler->n_devices);
 102
 103         discover_server_notify_device_remove(handler->server, device->device);
 104
 105         talloc_free(device);
 106 }
 107
 108 /**
 109  * device_handler_get_device_count - Get the count of current handler devices.
 110  */
 111
 112 int device_handler_get_device_count(const struct device_handler *handler)
 113 {
 114         return handler->n_devices;
 115 }
 116
 117 /**
 118  * device_handler_get_device - Get a handler device by index.
 119  */
 120
 121 const struct device *device_handler_get_device(
 122         const struct device_handler *handler, unsigned int index)
 123 {
 124         if (index >= handler->n_devices) {
 125                 assert(0 && "bad index");
 126                 return NULL;
 127         }
 128
 129         return handler->devices[index]->device;
 130 }
 131
 132 static void setup_device_links(struct discover_context *ctx)
 133 {
 134         struct discover_device *dev = ctx->device;
 135         struct link {
 136                 char *env, *dir;
 137         } *link, links[] = {
 138                 {
 139                         .env = "ID_FS_UUID",
 140                         .dir = "disk/by-uuid"
 141                 },
 142                 {
 143                         .env = "ID_FS_LABEL",
 144                         .dir = "disk/by-label"
 145                 },
 146                 {
 147                         .env = NULL
 148                 }
 149         };
 150
 151         for (link = links; link->env; link++) {
 152                 char *enc, *dir, *path;
 153                 const char *value;
 154
 155                 value = event_get_param(ctx->event, link->env);
 156                 if (!value || !*value)
 157                         continue;
 158
 159                 enc = encode_label(ctx, value);
 160                 dir = join_paths(ctx, mount_base(), link->dir);
 161                 path = join_paths(dev, dir, value);
 162
 163                 if (!pb_mkdir_recursive(dir)) {
 164                         unlink(path);
 165                         if (symlink(dev->mount_path, path)) {
 166                                 pb_log("symlink(%s,%s): %s\n",
 167                                                 dev->mount_path, path,
 168                                                 strerror(errno));
 169                                 talloc_free(path);
 170                         } else {
 171                                 int i = dev->n_links++;
 172                                 dev->links = talloc_realloc(dev,
 173                                                 dev->links, char *,
 174                                                 dev->n_links);
 175                                 dev->links[i] = path;
 176                         }
 177
 178                 }
 179
 180                 talloc_free(dir);
 181                 talloc_free(enc);
 182         }
 183 }
 184
 185 static void remove_device_links(struct discover_device *dev)
 186 {
 187         int i;
 188
 189         for (i = 0; i < dev->n_links; i++)
 190                 unlink(dev->links[i]);
 191 }
 192
 193 static int mount_device(struct discover_context *ctx)
 194 {
 195         struct discover_device *dev = ctx->device;
 196         const char *mountpoint;
 197         const char *argv[6];
 198
 199         if (!dev->mount_path) {
 200                 mountpoint = mountpoint_for_device(dev->device_path);
 201                 dev->mount_path = talloc_strdup(dev, mountpoint);
 202         }
 203
 204         if (pb_mkdir_recursive(dev->mount_path))
 205                 pb_log("couldn't create mount directory %s: %s\n",
 206                                 dev->mount_path, strerror(errno));
 207
 208         argv[0] = pb_system_apps.mount;
 209         argv[1] = dev->device_path;
 210         argv[2] = dev->mount_path;
 211         argv[3] = "-o";
 212         argv[4] = "ro";
 213         argv[5] = NULL;
 214
 215         if (pb_run_cmd(argv, 1, 0)) {
 216
 217                 /* Retry mount without ro option. */
 218
 219                 argv[0] = pb_system_apps.mount;
 220                 argv[1] = dev->device_path;
 221                 argv[2] = dev->mount_path;
 222                 argv[3] = NULL;
 223
 224                 if (pb_run_cmd(argv, 1, 0))
 225                         goto out_rmdir;
 226         }
 227
 228         setup_device_links(ctx);
 229         return 0;
 230
 231 out_rmdir:
 232         pb_rmdir_recursive(mount_base(), dev->mount_path);
 233         return -1;
 234 }
 235
 236 static int umount_device(struct discover_device *dev)
 237 {
 238         int status;
 239         pid_t pid;
 240
 241         remove_device_links(dev);
 242
 243         if (!dev->mount_path)
 244                 return 0;
 245
 246         pid = fork();
 247         if (pid == -1) {
 248                 pb_log("%s: fork failed: %s\n", __func__, strerror(errno));
 249                 return -1;
 250         }
 251
 252         if (pid == 0) {
 253                 execl(pb_system_apps.umount, pb_system_apps.umount,
 254                                                 dev->mount_path, NULL);
 255                 exit(EXIT_FAILURE);
 256         }
 257
 258         if (waitpid(pid, &status, 0) == -1) {
 259                 pb_log("%s: waitpid failed: %s\n", __func__,
 260                                 strerror(errno));
 261                 return -1;
 262         }
 263
 264         if (!WIFEXITED(status) || WEXITSTATUS(status) != 0)
 265                 return -1;
 266
 267         pb_rmdir_recursive(mount_base(), dev->mount_path);
 268
 269         return 0;
 270 }
 271
 272 static struct discover_device *find_device(struct device_handler *handler,
 273                 const char *id)
 274 {
 275         struct discover_device *dev;
 276         unsigned int i;
 277
 278         for (i = 0; i < handler->n_devices; i++) {
 279                 dev = handler->devices[i];
 280                 if (!strcmp(dev->device->id, id))
 281                         return dev;
 282         }
 283
 284         return NULL;
 285 }
 286
 287 static int destroy_device(void *arg)
 288 {
 289         struct discover_device *dev = arg;
 290
 291         umount_device(dev);
 292
 293         return 0;
 294 }
 295
 296 static struct discover_device *discover_device_create(
 297                 struct device_handler *handler,
 298                 struct discover_context *ctx,
 299                 struct event *event)
 300 {
 301         struct discover_device *dev;
 302         const char *devname;
 303
 304         dev = find_device(handler, event->device);
 305         if (dev)
 306                 return dev;
 307
 308         dev = talloc_zero(ctx, struct discover_device);
 309         dev->device = talloc_zero(dev, struct device);
 310         list_init(&dev->device->boot_options);
 311
 312         devname = event_get_param(ctx->event, "DEVNAME");
 313         if (devname)
 314                 dev->device_path = talloc_strdup(dev, devname);
 315
 316         dev->device->id = talloc_strdup(dev, event->device);
 317
 318         talloc_set_destructor(dev, destroy_device);
 319
 320         return dev;
 321 }
 322
 323 static int handle_add_udev_event(struct device_handler *handler,
 324                 struct event *event)
 325 {
 326         struct discover_context *ctx;
 327         struct discover_device *dev;
 328         int rc;
 329
 330         /* create our context */
 331         ctx = talloc(handler, struct discover_context);
 332         ctx->event = event;
 333         list_init(&ctx->boot_options);
 334
 335         /* create our top-level device */
 336         dev = discover_device_create(handler, ctx, event);
 337
 338         ctx->device = dev;
 339
 340         rc = mount_device(ctx);
 341         if (rc) {
 342                 talloc_free(ctx);
 343                 return 0;
 344         }
 345
 346         /* run the parsers. This will populate the ctx's boot_option list. */
 347         iterate_parsers(ctx);
 348
 349         /* add discovered stuff to the handler */
 350         context_commit(handler, ctx);
 351
 352         talloc_free(ctx);
 353
 354         return 0;
 355 }
 356
 357 static int handle_remove_udev_event(struct device_handler *handler,
 358                 struct event *event)
 359 {
 360         struct discover_device *dev;
 361
 362         dev = find_device(handler, event->device);
 363         if (!dev)
 364                 return 0;
 365
 366         /* remove device from handler device array */
 367         device_handler_remove(handler, dev);
 368
 369         return 0;
 370 }
 371
 372 static int handle_add_user_event(struct device_handler *handler,
 373                 struct event *event)
 374 {
 375         struct discover_context *ctx;
 376         struct discover_device *dev;
 377         int rc;
 378
 379         assert(event->device);
 380
 381         ctx = talloc(handler, struct discover_context);
 382         ctx->event = event;
 383         list_init(&ctx->boot_options);
 384
 385         dev = discover_device_create(handler, ctx, event);
 386         ctx->device = dev;
 387
 388         rc = parse_user_event(ctx, event);
 389
 390         if (!rc)
 391                 context_commit(handler, ctx);
 392
 393         return rc;
 394 }
 395
 396 static int handle_remove_user_event(struct device_handler *handler,
 397                 struct event *event)
 398 {
 399         struct discover_device *dev = find_device(handler, event->device);
 400
 401         if (!dev)
 402                 return 0;
 403
 404         /* remove device from handler device array */
 405         device_handler_remove(handler, dev);
 406
 407         return 0;
 408 }
 409
 410 typedef int (*event_handler)(struct device_handler *, struct event *);
 411
 412 static event_handler handlers[EVENT_TYPE_MAX][EVENT_ACTION_MAX] = {
 413         [EVENT_TYPE_UDEV] = {
 414                 [EVENT_ACTION_ADD]      = handle_add_udev_event,
 415                 [EVENT_ACTION_REMOVE]   = handle_remove_udev_event,
 416         },
 417         [EVENT_TYPE_USER] = {
 418                 [EVENT_ACTION_ADD]      = handle_add_user_event,
 419                 [EVENT_ACTION_REMOVE]   = handle_remove_user_event,
 420         }
 421 };
 422
 423 int device_handler_event(struct device_handler *handler,
 424                 struct event *event)
 425 {
 426         if (event->type >= EVENT_TYPE_MAX ||
 427                         event->action >= EVENT_ACTION_MAX ||
 428                         !handlers[event->type][event->action]) {
 429                 pb_log("%s unknown type/action: %d/%d\n", __func__,
 430                                 event->type, event->action);
 431                 return 0;
 432         }
 433
 434         return handlers[event->type][event->action](handler, event);
 435 }
 436
 437 struct device_handler *device_handler_init(struct discover_server *server,
 438                 int dry_run)
 439 {
 440         struct device_handler *handler;
 441
 442         handler = talloc(NULL, struct device_handler);
 443         handler->devices = NULL;
 444         handler->n_devices = 0;
 445         handler->server = server;
 446         handler->dry_run = dry_run;
 447
 448         /* set up our mount point base */
 449         pb_mkdir_recursive(mount_base());
 450
 451         parser_init();
 452
 453         return handler;
 454 }
 455
 456 void device_handler_destroy(struct device_handler *handler)
 457 {
 458         talloc_free(handler);
 459 }
 460
 461 static struct boot_option *find_boot_option_by_id(
 462                 struct device_handler *handler, const char *id)
 463 {
 464         unsigned int i;
 465
 466         for (i = 0; i < handler->n_devices; i++) {
 467                 struct discover_device *dev = handler->devices[i];
 468                 struct boot_option *opt;
 469
 470                 list_for_each_entry(&dev->device->boot_options, opt, list)
 471                         if (!strcmp(opt->id, id))
 472                                 return opt;
 473         }
 474
 475         return NULL;
 476 }
 477
 478 void device_handler_boot(struct device_handler *handler,
 479                 struct boot_command *cmd)
 480 {
 481         struct boot_option *opt;
 482
 483         opt = find_boot_option_by_id(handler, cmd->option_id);
 484
 485         boot(handler, opt, cmd, handler->dry_run);
 486 }