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         if (mp)
  93                 return mp;
  94
  95         if (asprintf(&dev, "/dev/mapper/%s", device) == -1)
  96                 exit(ENOMEM);
  97
  98         mp = find_mount_point(dev, 0);
  99         free(dev);
 100
 101         return mp;
 102 }
 103
 104 static int
 105 block(char *cmd, char *action, char *device)
 106 {
 107         pid_t pid = fork();
 108         int ret = -1;
 109         int status;
 110         char *argv[5] = { 0 };
 111         int a = 0;
 112
 113         switch (pid) {
 114         case -1:
 115                 ULOG_ERR("failed to fork block process\n");
 116                 break;
 117
 118         case 0:
 119                 argv[a++] = "/sbin/block";
 120                 argv[a++] = cmd;
 121                 argv[a++] = action;
 122                 argv[a++] = device;
 123                 execvp(argv[0], argv);
 124                 ULOG_ERR("failed to spawn %s %s %s\n", *argv, action, device);
 125                 exit(EXIT_FAILURE);
 126
 127         default:
 128                 waitpid(pid, &status, 0);
 129                 ret = WEXITSTATUS(status);
 130                 if (ret)
 131                         ULOG_ERR("failed to run block. %s/%s\n", action, device);
 132                 break;
 133         }
 134
 135         return ret;
 136 }
 137
 138 static int send_block_notification(struct ubus_context *ctx, const char *action,
 139                             const char *devname);
 140 static int hotplug_call_mount(struct ubus_context *ctx, const char *action,
 141                               const char *devname, uloop_process_handler cb, void *priv)
 142 {
 143         char * const argv[] = { "hotplug-call", "mount", NULL };
 144         struct hotplug_context *c = NULL;
 145         pid_t pid;
 146         int err;
 147
 148         if (cb) {
 149                 c = calloc(1, sizeof(*c));
 150                 if (!c)
 151                         return -ENOMEM;
 152         }
 153
 154         pid = fork();
 155         switch (pid) {
 156         case -1:
 157                 err = -errno;
 158                 ULOG_ERR("fork() failed\n");
 159                 return err;
 160         case 0:
 161                 uloop_end();
 162
 163                 setenv("ACTION", action, 1);
 164                 setenv("DEVICE", devname, 1);
 165
 166                 execv("/sbin/hotplug-call", argv);
 167                 exit(-1);
 168                 break;
 169         default:
 170                 if (c) {
 171                         c->process.pid = pid;
 172                         c->process.cb = cb;
 173                         c->priv = priv;
 174                         uloop_process_add(&c->process);
 175                 }
 176                 break;
 177         }
 178
 179         send_block_notification(ctx, action, devname);
 180
 181         return 0;
 182 }
 183
 184 static void device_mount_remove_hotplug_cb(struct uloop_process *p, int stat)
 185 {
 186         struct hotplug_context *hctx = container_of(p, struct hotplug_context, process);
 187         struct device *device = hctx->priv;
 188         char *mp;
 189
 190         if (device->target)
 191                 unlink(device->target);
 192
 193         mp = _find_mount_point(device->name);
 194         if (mp) {
 195                 block("autofs", "remove", device->name);
 196                 free(mp);
 197         }
 198
 199         free(device);
 200         free(hctx);
 201 }
 202
 203 static void device_mount_remove(struct ubus_context *ctx, struct device *device)
 204 {
 205         hotplug_call_mount(ctx, "remove", device->name,
 206                            device_mount_remove_hotplug_cb, device);
 207 }
 208
 209 static void device_mount_add(struct ubus_context *ctx, struct device *device)
 210 {
 211         struct stat st;
 212         char *path, *tmp;
 213
 214         if (asprintf(&path, "/tmp/run/blockd/%s", device->name) == -1)
 215                 exit(ENOMEM);
 216
 217         if (!lstat(device->target, &st)) {
 218                 if (S_ISLNK(st.st_mode))
 219                         unlink(device->target);
 220                 else if (S_ISDIR(st.st_mode))
 221                         rmdir(device->target);
 222         }
 223
 224         tmp = strrchr(device->target, '/');
 225         if (tmp && tmp != device->target && tmp != &device->target[strlen(path)-1]) {
 226                 *tmp = '\0';
 227                 mkdir_p(device->target, 0755);
 228                 *tmp = '/';
 229         }
 230
 231         if (symlink(path, device->target))
 232                 ULOG_ERR("failed to symlink %s->%s (%d) - %m\n", device->target, path, errno);
 233         else
 234                 hotplug_call_mount(ctx, "add", device->name, NULL, NULL);
 235
 236         free(path);
 237 }
 238
 239 static int
 240 device_move(struct device *device_o, struct device *device_n)
 241 {
 242         char *path;
 243
 244         if (device_o->autofs != device_n->autofs)
 245                 return -1;
 246
 247         if (device_o->anon || device_n->anon)
 248                 return -1;
 249
 250         if (device_o->autofs) {
 251                 unlink(device_o->target);
 252                 if (asprintf(&path, "/tmp/run/blockd/%s", device_n->name) == -1)
 253                         exit(ENOMEM);
 254
 255                 if (symlink(path, device_n->target))
 256                         ULOG_ERR("failed to symlink %s->%s (%d) - %m\n", device_n->target, path, errno);
 257
 258                 free(path);
 259         } else {
 260                 mkdir(device_n->target, 0755);
 261                 if (mount(device_o->target, device_n->target, NULL, MS_MOVE, NULL))
 262                         rmdir(device_n->target);
 263                 else
 264                         rmdir(device_o->target);
 265         }
 266
 267         return 0;
 268 }
 269
 270 static void vlist_nop_update(struct vlist_tree *tree,
 271                              struct vlist_node *node_new,
 272                              struct vlist_node *node_old)
 273 {
 274 }
 275
 276 VLIST_TREE(devices, avl_strcmp, vlist_nop_update, false, false);
 277
 278 static int
 279 block_hotplug(struct ubus_context *ctx, struct ubus_object *obj,
 280               struct ubus_request_data *req, const char *method,
 281               struct blob_attr *msg)
 282 {
 283         struct blob_attr *data[__MOUNT_MAX];
 284         struct device *device;
 285         struct blob_attr *_msg;
 286         char *devname, *_name;
 287         char *target = NULL, *__target;
 288         char *_target = NULL;
 289
 290         blobmsg_parse(mount_policy, __MOUNT_MAX, data, blob_data(msg), blob_len(msg));
 291
 292         if (!data[MOUNT_DEVICE])
 293                 return UBUS_STATUS_INVALID_ARGUMENT;
 294
 295         devname = blobmsg_get_string(data[MOUNT_DEVICE]);
 296
 297         if (data[MOUNT_TARGET]) {
 298                 target = blobmsg_get_string(data[MOUNT_TARGET]);
 299         } else {
 300                 if (asprintf(&_target, "/mnt/%s",
 301                              blobmsg_get_string(data[MOUNT_DEVICE])) == -1)
 302                         exit(ENOMEM);
 303
 304                 target = _target;
 305         }
 306
 307         if (data[MOUNT_REMOVE])
 308                 device = vlist_find(&devices, devname, device, node);
 309         else
 310                 device = calloc_a(sizeof(*device), &_msg, blob_raw_len(msg),
 311                                   &_name, strlen(devname) + 1, &__target, strlen(target) + 1);
 312
 313         if (!device) {
 314                 if (_target)
 315                         free(_target);
 316
 317                 return UBUS_STATUS_UNKNOWN_ERROR;
 318         }
 319
 320         if (data[MOUNT_REMOVE]) {
 321                 vlist_delete(&devices, &device->node);
 322
 323                 if (device->autofs)
 324                         device_mount_remove(ctx, device);
 325                 else
 326                         free(device);
 327
 328                 if (_target)
 329                         free(_target);
 330         } else {
 331                 struct device *old = vlist_find(&devices, devname, device, node);
 332
 333                 device->autofs = data[MOUNT_AUTOFS] ? blobmsg_get_u32(data[MOUNT_AUTOFS]) : 0;
 334                 device->anon = data[MOUNT_ANON] ? blobmsg_get_u32(data[MOUNT_ANON]) : 0;
 335                 device->msg = _msg;
 336                 memcpy(_msg, msg, blob_raw_len(msg));
 337                 device->name = _name;
 338                 strcpy(_name, devname);
 339                 device->target = __target;
 340                 strcpy(__target, target);
 341                 if (_target)
 342                         free(_target);
 343
 344                 vlist_add(&devices, &device->node, device->name);
 345
 346                 if (old && !device_move(old, device)) {
 347                         if (device->autofs) {
 348                                 device_mount_remove(ctx, old);
 349                                 device_mount_add(ctx, device);
 350                         } else {
 351                                 block("mount", NULL, NULL);
 352                         }
 353                 } else if (device->autofs) {
 354                         device_mount_add(ctx, device);
 355                 }
 356         }
 357
 358         return 0;
 359 }
 360
 361 static int blockd_mount(struct ubus_context *ctx, struct ubus_object *obj,
 362                         struct ubus_request_data *req, const char *method,
 363                         struct blob_attr *msg)
 364 {
 365         struct blob_attr *data[__MOUNT_MAX];
 366         struct device *device;
 367         char *devname;
 368
 369         blobmsg_parse(mount_policy, __MOUNT_MAX, data, blob_data(msg), blob_len(msg));
 370
 371         if (!data[MOUNT_DEVICE])
 372                 return UBUS_STATUS_INVALID_ARGUMENT;
 373
 374         devname = blobmsg_get_string(data[MOUNT_DEVICE]);
 375
 376         device = vlist_find(&devices, devname, device, node);
 377         if (!device)
 378                 return UBUS_STATUS_UNKNOWN_ERROR;
 379
 380         hotplug_call_mount(ctx, "add", device->name, NULL, NULL);
 381
 382         return 0;
 383 }
 384
 385 struct blockd_umount_context {
 386         struct ubus_context *ctx;
 387         struct ubus_request_data req;
 388 };
 389
 390 static void blockd_umount_hotplug_cb(struct uloop_process *p, int stat)
 391 {
 392         struct hotplug_context *hctx = container_of(p, struct hotplug_context, process);
 393         struct blockd_umount_context *c = hctx->priv;
 394
 395         ubus_complete_deferred_request(c->ctx, &c->req, 0);
 396
 397         free(c);
 398         free(hctx);
 399 }
 400
 401 static int blockd_umount(struct ubus_context *ctx, struct ubus_object *obj,
 402                          struct ubus_request_data *req, const char *method,
 403                          struct blob_attr *msg)
 404 {
 405         struct blob_attr *data[__MOUNT_MAX];
 406         struct blockd_umount_context *c;
 407         char *devname;
 408         int err;
 409
 410         blobmsg_parse(mount_policy, __MOUNT_MAX, data, blob_data(msg), blob_len(msg));
 411
 412         if (!data[MOUNT_DEVICE])
 413                 return UBUS_STATUS_INVALID_ARGUMENT;
 414
 415         devname = blobmsg_get_string(data[MOUNT_DEVICE]);
 416
 417         c = calloc(1, sizeof(*c));
 418         if (!c)
 419                 return UBUS_STATUS_UNKNOWN_ERROR;
 420
 421         c->ctx = ctx;
 422         ubus_defer_request(ctx, req, &c->req);
 423
 424         err = hotplug_call_mount(ctx, "remove", devname, blockd_umount_hotplug_cb, c);
 425         if (err) {
 426                 free(c);
 427                 return UBUS_STATUS_UNKNOWN_ERROR;
 428         }
 429
 430         return 0;
 431 }
 432
 433 static void block_info_dump(struct blob_buf *b, struct device *device)
 434 {
 435         struct blob_attr *v;
 436         char *mp;
 437         int rem;
 438
 439         blob_for_each_attr(v, device->msg, rem)
 440                 blobmsg_add_blob(b, v);
 441
 442         mp = _find_mount_point(device->name);
 443         if (mp) {
 444                 blobmsg_add_string(b, "mount", mp);
 445                 free(mp);
 446         } else if (device->autofs && device->target) {
 447                 blobmsg_add_string(b, "mount", device->target);
 448         }
 449 }
 450
 451 static int
 452 block_info(struct ubus_context *ctx, struct ubus_object *obj,
 453            struct ubus_request_data *req, const char *method,
 454            struct blob_attr *msg)
 455 {
 456         struct blob_attr *data[__INFO_MAX];
 457         struct device *device = NULL;
 458
 459         blobmsg_parse(info_policy, __INFO_MAX, data, blob_data(msg), blob_len(msg));
 460
 461         if (data[INFO_DEVICE]) {
 462                 device = vlist_find(&devices, blobmsg_get_string(data[INFO_DEVICE]), device, node);
 463                 if (!device)
 464                         return UBUS_STATUS_INVALID_ARGUMENT;
 465         }
 466
 467         blob_buf_init(&bb, 0);
 468         if (device) {
 469                 block_info_dump(&bb, device);
 470         } else {
 471                 void *a;
 472
 473                 a = blobmsg_open_array(&bb, "devices");
 474                 vlist_for_each_element(&devices, device, node) {
 475                         void *t;
 476
 477                         t = blobmsg_open_table(&bb, "");
 478                         block_info_dump(&bb, device);
 479                         blobmsg_close_table(&bb, t);
 480                 }
 481                 blobmsg_close_array(&bb, a);
 482         }
 483         ubus_send_reply(ctx, req, bb.head);
 484
 485         return 0;
 486 }
 487
 488 static const struct ubus_method block_methods[] = {
 489         UBUS_METHOD("hotplug", block_hotplug, mount_policy),
 490         UBUS_METHOD("mount", blockd_mount, mount_policy),
 491         UBUS_METHOD("umount", blockd_umount, mount_policy),
 492         UBUS_METHOD("info", block_info, info_policy),
 493 };
 494
 495 static struct ubus_object_type block_object_type =
 496         UBUS_OBJECT_TYPE("block", block_methods);
 497
 498 static struct ubus_object block_object = {
 499         .name = "block",
 500         .type = &block_object_type,
 501         .methods = block_methods,
 502         .n_methods = ARRAY_SIZE(block_methods),
 503 };
 504
 505 /* send ubus event for successful mounts, useful for procd triggers */
 506 static int send_block_notification(struct ubus_context *ctx, const char *action,
 507                             const char *devname)
 508 {
 509         struct blob_buf buf = { 0 };
 510         char evname[16] = "mount.";
 511         int err;
 512
 513         if (!ctx)
 514                 return -ENXIO;
 515
 516         strncat(evname, action, sizeof(evname) - 1);
 517
 518         blob_buf_init(&buf, 0);
 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))
 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);
 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         int 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(struct uloop_timeout *t)
 636 {
 637         block("autofs", "start", NULL);
 638 }
 639
 640 struct uloop_timeout startup = {
 641         .cb = blockd_startup,
 642 };
 643
 644 int main(int argc, char **argv)
 645 {
 646         /* make sure blockd is in it's own POSIX process group */
 647         setpgrp();
 648
 649         ulog_open(ULOG_SYSLOG | ULOG_STDIO, LOG_DAEMON, "blockd");
 650         uloop_init();
 651
 652         autofs_mount();
 653
 654         conn.cb = ubus_connect_handler;
 655         ubus_auto_connect(&conn);
 656
 657         uloop_timeout_set(&startup, 1000);
 658
 659         uloop_run();
 660         uloop_done();
 661
 662         autofs_umount();
 663
 664         vlist_flush_all(&devices);
 665
 666         return 0;
 667 }