blockd.c

   1 #define _GNU_SOURCE
   2 #include <sys/stat.h>
   3 #include <sys/mount.h>
   4 #include <sys/wait.h>
   5
   6 #include <stdlib.h>
   7 #include <stdio.h>
   8 #include <unistd.h>
   9 #include <fcntl.h>
  10
  11 #include <errno.h>
  12
  13 #include <linux/limits.h>
  14 #include <linux/auto_fs4.h>
  15
  16 #include <libubox/uloop.h>
  17 #include <libubox/vlist.h>
  18 #include <libubox/ulog.h>
  19 #include <libubox/avl-cmp.h>
  20 #include <libubus.h>
  21
  22 #include "libfstools/libfstools.h"
  23
  24 #define AUTOFS_MOUNT_PATH       "/tmp/run/blockd/"
  25 #define AUTOFS_TIMEOUT          30
  26 #define AUTOFS_EXPIRE_TIMER     (5 * 1000)
  27
  28 struct hotplug_context {
  29         struct uloop_process process;
  30         void *priv;
  31 };
  32
  33 struct device {
  34         struct vlist_node node;
  35         struct blob_attr *msg;
  36         char *name;
  37         char *target;
  38         int autofs;
  39         int anon;
  40 };
  41
  42 static struct uloop_fd fd_autofs_read;
  43 static int fd_autofs_write = 0;
  44 static struct ubus_auto_conn conn;
  45 struct blob_buf bb = { 0 };
  46
  47 enum {
  48         MOUNT_UUID,
  49         MOUNT_LABEL,
  50         MOUNT_ENABLE,
  51         MOUNT_TARGET,
  52         MOUNT_DEVICE,
  53         MOUNT_OPTIONS,
  54         MOUNT_AUTOFS,
  55         MOUNT_ANON,
  56         MOUNT_REMOVE,
  57         __MOUNT_MAX
  58 };
  59
  60 static const struct blobmsg_policy mount_policy[__MOUNT_MAX] = {
  61         [MOUNT_UUID] = { .name = "uuid", .type = BLOBMSG_TYPE_STRING },
  62         [MOUNT_LABEL] = { .name = "label", .type = BLOBMSG_TYPE_STRING },
  63         [MOUNT_DEVICE] = { .name = "device", .type = BLOBMSG_TYPE_STRING },
  64         [MOUNT_TARGET] = { .name = "target", .type = BLOBMSG_TYPE_STRING },
  65         [MOUNT_OPTIONS] = { .name = "options", .type = BLOBMSG_TYPE_STRING },
  66         [MOUNT_ENABLE] = { .name = "enabled", .type = BLOBMSG_TYPE_INT32 },
  67         [MOUNT_AUTOFS] = { .name = "autofs", .type = BLOBMSG_TYPE_INT32 },
  68         [MOUNT_ANON] = { .name = "anon", .type = BLOBMSG_TYPE_INT32 },
  69         [MOUNT_REMOVE] = { .name = "remove", .type = BLOBMSG_TYPE_INT32 },
  70 };
  71
  72 enum {
  73         INFO_DEVICE,
  74         __INFO_MAX
  75 };
  76
  77 static const struct blobmsg_policy info_policy[__INFO_MAX] = {
  78         [INFO_DEVICE] = { .name = "device", .type = BLOBMSG_TYPE_STRING },
  79 };
  80
  81 static char*
  82 _find_mount_point(char *device)
  83 {
  84         char *dev, *mp;
  85
  86         if (asprintf(&dev, "/dev/%s", device) == -1)
  87                 exit(ENOMEM);
  88
  89         mp = find_mount_point(dev, 0);
  90         free(dev);
  91
  92         return mp;
  93 }
  94
  95 static int
  96 block(char *cmd, char *action, char *device, int sync, struct uloop_process *process)
  97 {
  98         pid_t pid = fork();
  99         int ret = sync;
 100         int status;
 101         char *argv[5] = { 0 };
 102         int a = 0;
 103
 104         switch (pid) {
 105         case -1:
 106                 ULOG_ERR("failed to fork block process\n");
 107                 break;
 108
 109         case 0:
 110                 uloop_end();
 111
 112                 argv[a++] = "/sbin/block";
 113                 argv[a++] = cmd;
 114                 argv[a++] = action;
 115                 argv[a++] = device;
 116                 execvp(argv[0], argv);
 117                 ULOG_ERR("failed to spawn %s %s %s\n", *argv, action, device);
 118                 exit(EXIT_FAILURE);
 119
 120         default:
 121                 if (!sync && process) {
 122                         process->pid = pid;
 123                         uloop_process_add(process);
 124                 } else if (sync) {
 125                         waitpid(pid, &status, 0);
 126                         ret = WEXITSTATUS(status);
 127                         if (ret)
 128                                 ULOG_ERR("failed to run block. %s/%s\n", action, device);
 129                 }
 130                 break;
 131         }
 132
 133         return ret;
 134 }
 135
 136 static int send_block_notification(struct ubus_context *ctx, const char *action,
 137                             const char *devname);
 138 static int hotplug_call_mount(struct ubus_context *ctx, const char *action,
 139                               const char *devname, uloop_process_handler cb, void *priv)
 140 {
 141         char * const argv[] = { "hotplug-call", "mount", NULL };
 142         struct hotplug_context *c = NULL;
 143         pid_t pid;
 144         int err;
 145
 146         if (cb) {
 147                 c = calloc(1, sizeof(*c));
 148                 if (!c)
 149                         return -ENOMEM;
 150         }
 151
 152         pid = fork();
 153         switch (pid) {
 154         case -1:
 155                 err = -errno;
 156                 ULOG_ERR("fork() failed\n");
 157                 return err;
 158         case 0:
 159                 uloop_end();
 160
 161                 setenv("ACTION", action, 1);
 162                 setenv("DEVICE", devname, 1);
 163
 164                 execv("/sbin/hotplug-call", argv);
 165                 exit(-1);
 166                 break;
 167         default:
 168                 if (c) {
 169                         c->process.pid = pid;
 170                         c->process.cb = cb;
 171                         c->priv = priv;
 172                         uloop_process_add(&c->process);
 173                 }
 174                 break;
 175         }
 176
 177         send_block_notification(ctx, action, devname);
 178
 179         return 0;
 180 }
 181
 182 static void device_mount_remove_hotplug_cb(struct uloop_process *p, int stat)
 183 {
 184         struct hotplug_context *hctx = container_of(p, struct hotplug_context, process);
 185         struct device *device = hctx->priv;
 186         char *mp;
 187
 188         if (device->target)
 189                 unlink(device->target);
 190
 191         mp = _find_mount_point(device->name);
 192         if (mp) {
 193                 block("autofs", "remove", device->name, 0, NULL);
 194                 free(mp);
 195         }
 196
 197         free(device);
 198         free(hctx);
 199 }
 200
 201 static void device_mount_remove(struct ubus_context *ctx, struct device *device)
 202 {
 203         hotplug_call_mount(ctx, "remove", device->name,
 204                            device_mount_remove_hotplug_cb, device);
 205 }
 206
 207 static void device_mount_add(struct ubus_context *ctx, struct device *device)
 208 {
 209         struct stat st;
 210         char *path, *tmp;
 211
 212         if (asprintf(&path, "/tmp/run/blockd/%s", device->name) == -1)
 213                 exit(ENOMEM);
 214
 215         if (!lstat(device->target, &st)) {
 216                 if (S_ISLNK(st.st_mode))
 217                         unlink(device->target);
 218                 else if (S_ISDIR(st.st_mode))
 219                         rmdir(device->target);
 220         }
 221
 222         tmp = strrchr(device->target, '/');
 223         if (tmp && tmp != device->target && tmp != &device->target[strlen(path)-1]) {
 224                 *tmp = '\0';
 225                 mkdir_p(device->target, 0755);
 226                 *tmp = '/';
 227         }
 228
 229         if (symlink(path, device->target))
 230                 ULOG_ERR("failed to symlink %s->%s (%d) - %m\n", device->target, path, errno);
 231         else
 232                 hotplug_call_mount(ctx, "add", device->name, NULL, NULL);
 233
 234         free(path);
 235 }
 236
 237 static int
 238 device_move(struct device *device_o, struct device *device_n)
 239 {
 240         char *path;
 241
 242         if (device_o->autofs != device_n->autofs)
 243                 return -1;
 244
 245         if (device_o->anon || device_n->anon)
 246                 return -1;
 247
 248         if (device_o->autofs) {
 249                 unlink(device_o->target);
 250                 if (asprintf(&path, "/tmp/run/blockd/%s", device_n->name) == -1)
 251                         exit(ENOMEM);
 252
 253                 if (symlink(path, device_n->target))
 254                         ULOG_ERR("failed to symlink %s->%s (%d) - %m\n", device_n->target, path, errno);
 255
 256                 free(path);
 257         } else {
 258                 mkdir(device_n->target, 0755);
 259                 if (mount(device_o->target, device_n->target, NULL, MS_MOVE, NULL))
 260                         rmdir(device_n->target);
 261                 else
 262                         rmdir(device_o->target);
 263         }
 264
 265         return 0;
 266 }
 267
 268 static void vlist_nop_update(struct vlist_tree *tree,
 269                              struct vlist_node *node_new,
 270                              struct vlist_node *node_old)
 271 {
 272 }
 273
 274 VLIST_TREE(devices, avl_strcmp, vlist_nop_update, false, false);
 275
 276 static int
 277 block_hotplug(struct ubus_context *ctx, struct ubus_object *obj,
 278               struct ubus_request_data *req, const char *method,
 279               struct blob_attr *msg)
 280 {
 281         struct blob_attr *data[__MOUNT_MAX];
 282         struct device *device;
 283         struct blob_attr *_msg;
 284         char *devname, *_name;
 285         char *target = NULL, *__target;
 286         char *_target = NULL;
 287
 288         blobmsg_parse(mount_policy, __MOUNT_MAX, data, blob_data(msg), blob_len(msg));
 289
 290         if (!data[MOUNT_DEVICE])
 291                 return UBUS_STATUS_INVALID_ARGUMENT;
 292
 293         devname = blobmsg_get_string(data[MOUNT_DEVICE]);
 294
 295         if (data[MOUNT_TARGET]) {
 296                 target = blobmsg_get_string(data[MOUNT_TARGET]);
 297         } else {
 298                 if (asprintf(&_target, "/mnt/%s",
 299                              blobmsg_get_string(data[MOUNT_DEVICE])) == -1)
 300                         exit(ENOMEM);
 301
 302                 target = _target;
 303         }
 304
 305         if (data[MOUNT_REMOVE])
 306                 device = vlist_find(&devices, devname, device, node);
 307         else
 308                 device = calloc_a(sizeof(*device), &_msg, blob_raw_len(msg),
 309                                   &_name, strlen(devname) + 1, &__target, strlen(target) + 1);
 310
 311         if (!device) {
 312                 if (_target)
 313                         free(_target);
 314
 315                 return UBUS_STATUS_UNKNOWN_ERROR;
 316         }
 317
 318         if (data[MOUNT_REMOVE]) {
 319                 vlist_delete(&devices, &device->node);
 320
 321                 if (device->autofs)
 322                         device_mount_remove(ctx, device);
 323                 else
 324                         free(device);
 325
 326                 if (_target)
 327                         free(_target);
 328         } else {
 329                 struct device *old = vlist_find(&devices, devname, device, node);
 330
 331                 device->autofs = data[MOUNT_AUTOFS] ? blobmsg_get_u32(data[MOUNT_AUTOFS]) : 0;
 332                 device->anon = data[MOUNT_ANON] ? blobmsg_get_u32(data[MOUNT_ANON]) : 0;
 333                 device->msg = _msg;
 334                 memcpy(_msg, msg, blob_raw_len(msg));
 335                 device->name = _name;
 336                 strcpy(_name, devname);
 337                 device->target = __target;
 338                 strcpy(__target, target);
 339                 if (_target)
 340                         free(_target);
 341
 342                 vlist_add(&devices, &device->node, device->name);
 343
 344                 if (old && !device_move(old, device)) {
 345                         if (device->autofs) {
 346                                 device_mount_remove(ctx, old);
 347                                 device_mount_add(ctx, device);
 348                         } else {
 349                                 block("mount", NULL, NULL, 0, NULL);
 350                         }
 351                 } else if (device->autofs) {
 352                         device_mount_add(ctx, device);
 353                 }
 354         }
 355
 356         return 0;
 357 }
 358
 359 static int blockd_mount(struct ubus_context *ctx, struct ubus_object *obj,
 360                         struct ubus_request_data *req, const char *method,
 361                         struct blob_attr *msg)
 362 {
 363         struct blob_attr *data[__MOUNT_MAX];
 364         struct device *device;
 365         char *devname;
 366
 367         blobmsg_parse(mount_policy, __MOUNT_MAX, data, blob_data(msg), blob_len(msg));
 368
 369         if (!data[MOUNT_DEVICE])
 370                 return UBUS_STATUS_INVALID_ARGUMENT;
 371
 372         devname = blobmsg_get_string(data[MOUNT_DEVICE]);
 373
 374         device = vlist_find(&devices, devname, device, node);
 375         if (!device)
 376                 return UBUS_STATUS_UNKNOWN_ERROR;
 377
 378         hotplug_call_mount(ctx, "add", device->name, NULL, NULL);
 379
 380         return 0;
 381 }
 382
 383 struct blockd_umount_context {
 384         struct ubus_context *ctx;
 385         struct ubus_request_data req;
 386 };
 387
 388 static void blockd_umount_hotplug_cb(struct uloop_process *p, int stat)
 389 {
 390         struct hotplug_context *hctx = container_of(p, struct hotplug_context, process);
 391         struct blockd_umount_context *c = hctx->priv;
 392
 393         ubus_complete_deferred_request(c->ctx, &c->req, 0);
 394
 395         free(c);
 396         free(hctx);
 397 }
 398
 399 static int blockd_umount(struct ubus_context *ctx, struct ubus_object *obj,
 400                          struct ubus_request_data *req, const char *method,
 401                          struct blob_attr *msg)
 402 {
 403         struct blob_attr *data[__MOUNT_MAX];
 404         struct blockd_umount_context *c;
 405         char *devname;
 406         int err;
 407
 408         blobmsg_parse(mount_policy, __MOUNT_MAX, data, blob_data(msg), blob_len(msg));
 409
 410         if (!data[MOUNT_DEVICE])
 411                 return UBUS_STATUS_INVALID_ARGUMENT;
 412
 413         devname = blobmsg_get_string(data[MOUNT_DEVICE]);
 414
 415         c = calloc(1, sizeof(*c));
 416         if (!c)
 417                 return UBUS_STATUS_UNKNOWN_ERROR;
 418
 419         c->ctx = ctx;
 420         ubus_defer_request(ctx, req, &c->req);
 421
 422         err = hotplug_call_mount(ctx, "remove", devname, blockd_umount_hotplug_cb, c);
 423         if (err) {
 424                 free(c);
 425                 return UBUS_STATUS_UNKNOWN_ERROR;
 426         }
 427
 428         return 0;
 429 }
 430
 431 static void block_info_dump(struct blob_buf *b, struct device *device)
 432 {
 433         struct blob_attr *v;
 434         char *mp;
 435         int rem;
 436
 437         blob_for_each_attr(v, device->msg, rem)
 438                 blobmsg_add_blob(b, v);
 439
 440         mp = _find_mount_point(device->name);
 441         if (mp) {
 442                 blobmsg_add_string(b, "mount", mp);
 443                 free(mp);
 444         } else if (device->autofs && device->target) {
 445                 blobmsg_add_string(b, "mount", device->target);
 446         }
 447 }
 448
 449 static int
 450 block_info(struct ubus_context *ctx, struct ubus_object *obj,
 451            struct ubus_request_data *req, const char *method,
 452            struct blob_attr *msg)
 453 {
 454         struct blob_attr *data[__INFO_MAX];
 455         struct device *device = NULL;
 456
 457         blobmsg_parse(info_policy, __INFO_MAX, data, blob_data(msg), blob_len(msg));
 458
 459         if (data[INFO_DEVICE]) {
 460                 device = vlist_find(&devices, blobmsg_get_string(data[INFO_DEVICE]), device, node);
 461                 if (!device)
 462                         return UBUS_STATUS_INVALID_ARGUMENT;
 463         }
 464
 465         blob_buf_init(&bb, 0);
 466         if (device) {
 467                 block_info_dump(&bb, device);
 468         } else {
 469                 void *a;
 470
 471                 a = blobmsg_open_array(&bb, "devices");
 472                 vlist_for_each_element(&devices, device, node) {
 473                         void *t;
 474
 475                         t = blobmsg_open_table(&bb, "");
 476                         block_info_dump(&bb, device);
 477                         blobmsg_close_table(&bb, t);
 478                 }
 479                 blobmsg_close_array(&bb, a);
 480         }
 481         ubus_send_reply(ctx, req, bb.head);
 482
 483         return 0;
 484 }
 485
 486 static const struct ubus_method block_methods[] = {
 487         UBUS_METHOD("hotplug", block_hotplug, mount_policy),
 488         UBUS_METHOD("mount", blockd_mount, mount_policy),
 489         UBUS_METHOD("umount", blockd_umount, mount_policy),
 490         UBUS_METHOD("info", block_info, info_policy),
 491 };
 492
 493 static struct ubus_object_type block_object_type =
 494         UBUS_OBJECT_TYPE("block", block_methods);
 495
 496 static struct ubus_object block_object = {
 497         .name = "block",
 498         .type = &block_object_type,
 499         .methods = block_methods,
 500         .n_methods = ARRAY_SIZE(block_methods),
 501 };
 502
 503 /* send ubus event for successful mounts, useful for procd triggers */
 504 static int send_block_notification(struct ubus_context *ctx, const char *action,
 505                             const char *devname)
 506 {
 507         struct blob_buf buf = { 0 };
 508         char evname[16] = "mount.";
 509         int err;
 510
 511         if (!ctx)
 512                 return -ENXIO;
 513
 514         strncat(evname, action, sizeof(evname) - 1);
 515
 516         blob_buf_init(&buf, 0);
 517
 518         if (devname)
 519                 blobmsg_add_string(&buf, "devname", devname);
 520
 521         err = ubus_notify(ctx, &block_object, evname, buf.head, -1);
 522
 523         return err;
 524 }
 525
 526 static void
 527 ubus_connect_handler(struct ubus_context *ctx)
 528 {
 529         int ret;
 530
 531         ret = ubus_add_object(ctx, &block_object);
 532         if (ret)
 533                 fprintf(stderr, "Failed to add object: %s\n", ubus_strerror(ret));
 534 }
 535
 536 static int autofs_umount(void)
 537 {
 538         umount2(AUTOFS_MOUNT_PATH, MNT_DETACH);
 539         return 0;
 540 }
 541
 542 static void autofs_read_handler(struct uloop_fd *u, unsigned int events)
 543 {
 544         union autofs_v5_packet_union pktu;
 545         const struct autofs_v5_packet *pkt;
 546         int cmd = AUTOFS_IOC_READY;
 547         struct stat st;
 548
 549         while (read(u->fd, &pktu, sizeof(pktu)) == -1) {
 550                 if (errno != EINTR)
 551                         return;
 552                 continue;
 553         }
 554
 555         if (pktu.hdr.type != autofs_ptype_missing_indirect) {
 556                 ULOG_ERR("unknown packet type %d\n", pktu.hdr.type);
 557                 return;
 558         }
 559
 560         pkt = &pktu.missing_indirect;
 561         ULOG_ERR("kernel is requesting a mount -> %s\n", pkt->name);
 562         if (lstat(pkt->name, &st) == -1)
 563                 if (block("autofs", "add", (char *)pkt->name, 1, NULL))
 564                         cmd = AUTOFS_IOC_FAIL;
 565
 566         if (ioctl(fd_autofs_write, cmd, pkt->wait_queue_token) < 0)
 567                 ULOG_ERR("failed to report back to kernel\n");
 568 }
 569
 570 static void autofs_expire(struct uloop_timeout *t)
 571 {
 572         struct autofs_packet_expire pkt;
 573
 574         while (ioctl(fd_autofs_write, AUTOFS_IOC_EXPIRE, &pkt) == 0)
 575                 block("autofs", "remove", pkt.name, 1, NULL);
 576
 577         uloop_timeout_set(t, AUTOFS_EXPIRE_TIMER);
 578 }
 579
 580 struct uloop_timeout autofs_expire_timer = {
 581         .cb = autofs_expire,
 582 };
 583
 584 static int autofs_mount(void)
 585 {
 586         unsigned long autofs_timeout = AUTOFS_TIMEOUT;
 587         int kproto_version;
 588         int pipefd[2];
 589         char source[64];
 590         char opts[64];
 591
 592         if (pipe(pipefd) < 0) {
 593                 ULOG_ERR("failed to get kernel pipe\n");
 594                 return -1;
 595         }
 596
 597         snprintf(source, sizeof(source), "mountd(pid%u)", getpid());
 598         snprintf(opts, sizeof(opts), "fd=%d,pgrp=%u,minproto=5,maxproto=5", pipefd[1], (unsigned) getpgrp());
 599         mkdir(AUTOFS_MOUNT_PATH, 0555);
 600         if (mount(source, AUTOFS_MOUNT_PATH, "autofs", 0, opts)) {
 601                 ULOG_ERR("unable to mount autofs on %s\n", AUTOFS_MOUNT_PATH);
 602                 close(pipefd[0]);
 603                 close(pipefd[1]);
 604                 return -1;
 605         }
 606         close(pipefd[1]);
 607         fd_autofs_read.fd = pipefd[0];
 608         fd_autofs_read.cb = autofs_read_handler;
 609         uloop_fd_add(&fd_autofs_read, ULOOP_READ);
 610
 611         fd_autofs_write = open(AUTOFS_MOUNT_PATH, O_RDONLY);
 612         if(fd_autofs_write < 0) {
 613                 autofs_umount();
 614                 ULOG_ERR("failed to open direcory\n");
 615                 return -1;
 616         }
 617
 618         ioctl(fd_autofs_write, AUTOFS_IOC_PROTOVER, &kproto_version);
 619         if (kproto_version != 5) {
 620                 ULOG_ERR("only kernel protocol version 5 is tested. You have %d.\n",
 621                         kproto_version);
 622                 exit(EXIT_FAILURE);
 623         }
 624         if (ioctl(fd_autofs_write, AUTOFS_IOC_SETTIMEOUT, &autofs_timeout))
 625                 ULOG_ERR("failed to set autofs timeout\n");
 626
 627         uloop_timeout_set(&autofs_expire_timer, AUTOFS_EXPIRE_TIMER);
 628
 629         fcntl(fd_autofs_write, F_SETFD, fcntl(fd_autofs_write, F_GETFD) | FD_CLOEXEC);
 630         fcntl(fd_autofs_read.fd, F_SETFD, fcntl(fd_autofs_read.fd, F_GETFD) | FD_CLOEXEC);
 631
 632         return 0;
 633 }
 634
 635 static void blockd_startup_cb(struct uloop_process *p, int stat)
 636 {
 637         send_block_notification(&conn.ctx, "ready", NULL);
 638 }
 639
 640 static struct uloop_process startup_process = {
 641         .cb = blockd_startup_cb,
 642 };
 643
 644 static void blockd_startup(struct uloop_timeout *t)
 645 {
 646         block("autofs", "start", NULL, 0, &startup_process);
 647 }
 648
 649 struct uloop_timeout startup = {
 650         .cb = blockd_startup,
 651 };
 652
 653 int main(int argc, char **argv)
 654 {
 655         /* make sure blockd is in it's own POSIX process group */
 656         setpgrp();
 657
 658         ulog_open(ULOG_SYSLOG | ULOG_STDIO, LOG_DAEMON, "blockd");
 659         uloop_init();
 660
 661         autofs_mount();
 662
 663         conn.cb = ubus_connect_handler;
 664         ubus_auto_connect(&conn);
 665
 666         uloop_timeout_set(&startup, 1000);
 667
 668         uloop_run();
 669         uloop_done();
 670
 671         autofs_umount();
 672
 673         vlist_flush_all(&devices);
 674
 675         return 0;
 676 }