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         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->device->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 static int handle_add_udev_event(struct device_handler *handler,
 321                 struct event *event)
 322 {
 323         struct discover_context *ctx;
 324         struct discover_device *dev;
 325         int rc;
 326
 327         /* create our context */
 328         ctx = talloc(handler, struct discover_context);
 329         ctx->event = event;
 330         list_init(&ctx->boot_options);
 331
 332         /* create our top-level device */
 333         dev = discover_device_create(handler, ctx, event);
 334
 335         ctx->device = dev;
 336
 337         rc = mount_device(ctx);
 338         if (rc) {
 339                 talloc_free(ctx);
 340                 return 0;
 341         }
 342
 343         /* run the parsers. This will populate the ctx's boot_option list. */
 344         iterate_parsers(ctx);
 345
 346         /* add discovered stuff to the handler */
 347         context_commit(handler, ctx);
 348
 349         talloc_free(ctx);
 350
 351         return 0;
 352 }
 353
 354 static int handle_remove_udev_event(struct device_handler *handler,
 355                 struct event *event)
 356 {
 357         struct discover_device *dev;
 358
 359         dev = find_device(handler, event->device);
 360         if (!dev)
 361                 return 0;
 362
 363         /* remove device from handler device array */
 364         device_handler_remove(handler, dev);
 365
 366         return 0;
 367 }
 368
 369 static int handle_add_user_event(struct device_handler *handler,
 370                 struct event *event)
 371 {
 372         struct discover_context *ctx;
 373         struct discover_device *dev;
 374         int rc;
 375
 376         assert(event->device);
 377
 378         ctx = talloc(handler, struct discover_context);
 379         ctx->event = event;
 380         list_init(&ctx->boot_options);
 381
 382         dev = discover_device_create(handler, ctx, event);
 383         ctx->device = dev;
 384
 385         rc = parse_user_event(ctx, event);
 386
 387         if (!rc)
 388                 context_commit(handler, ctx);
 389
 390         return rc;
 391 }
 392
 393 static int handle_remove_user_event(struct device_handler *handler,
 394                 struct event *event)
 395 {
 396         struct discover_device *dev = find_device(handler, event->device);
 397
 398         if (!dev)
 399                 return 0;
 400
 401         /* remove device from handler device array */
 402         device_handler_remove(handler, dev);
 403
 404         return 0;
 405 }
 406
 407 typedef int (*event_handler)(struct device_handler *, struct event *);
 408
 409 static event_handler handlers[EVENT_TYPE_MAX][EVENT_ACTION_MAX] = {
 410         [EVENT_TYPE_UDEV] = {
 411                 [EVENT_ACTION_ADD]      = handle_add_udev_event,
 412                 [EVENT_ACTION_REMOVE]   = handle_remove_udev_event,
 413         },
 414         [EVENT_TYPE_USER] = {
 415                 [EVENT_ACTION_ADD]      = handle_add_user_event,
 416                 [EVENT_ACTION_REMOVE]   = handle_remove_user_event,
 417         }
 418 };
 419
 420 int device_handler_event(struct device_handler *handler,
 421                 struct event *event)
 422 {
 423         if (event->type >= EVENT_TYPE_MAX ||
 424                         event->action >= EVENT_ACTION_MAX ||
 425                         !handlers[event->type][event->action]) {
 426                 pb_log("%s unknown type/action: %d/%d\n", __func__,
 427                                 event->type, event->action);
 428                 return 0;
 429         }
 430
 431         return handlers[event->type][event->action](handler, event);
 432 }
 433
 434 struct device_handler *device_handler_init(struct discover_server *server,
 435                 int dry_run)
 436 {
 437         struct device_handler *handler;
 438
 439         handler = talloc(NULL, struct device_handler);
 440         handler->devices = NULL;
 441         handler->n_devices = 0;
 442         handler->server = server;
 443         handler->dry_run = dry_run;
 444
 445         /* set up our mount point base */
 446         pb_mkdir_recursive(mount_base());
 447
 448         parser_init();
 449
 450         return handler;
 451 }
 452
 453 void device_handler_destroy(struct device_handler *handler)
 454 {
 455         talloc_free(handler);
 456 }
 457
 458 static struct boot_option *find_boot_option_by_id(
 459                 struct device_handler *handler, const char *id)
 460 {
 461         unsigned int i;
 462
 463         for (i = 0; i < handler->n_devices; i++) {
 464                 struct discover_device *dev = handler->devices[i];
 465                 struct boot_option *opt;
 466
 467                 list_for_each_entry(&dev->device->boot_options, opt, list)
 468                         if (!strcmp(opt->id, id))
 469                                 return opt;
 470         }
 471
 472         return NULL;
 473 }
 474
 475 void device_handler_boot(struct device_handler *handler,
 476                 struct boot_command *cmd)
 477 {
 478         struct boot_option *opt;
 479
 480         opt = find_boot_option_by_id(handler, cmd->option_id);
 481
 482         boot(handler, opt, cmd, handler->dry_run);
 483 }