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, const char *target);
 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         return 0;
 178 }
 179
 180 static void device_mount_remove_hotplug_cb(struct uloop_process *p, int stat)
 181 {
 182         struct hotplug_context *hctx = container_of(p, struct hotplug_context, process);
 183         struct device *device = hctx->priv;
 184         char *mp;
 185
 186         if (device->target)
 187                 unlink(device->target);
 188
 189         mp = _find_mount_point(device->name);
 190         if (mp) {
 191                 block("autofs", "remove", device->name, 0, NULL);
 192                 free(mp);
 193         }
 194
 195         free(device);
 196         free(hctx);
 197 }
 198
 199 static void device_mount_remove(struct ubus_context *ctx, struct device *device)
 200 {
 201         static const char *action = "remove";
 202
 203         hotplug_call_mount(ctx, action, device->name,
 204                            device_mount_remove_hotplug_cb, device);
 205
 206         send_block_notification(ctx, action, device->name, device->target);
 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                 static const char *action = "add";
 235                 hotplug_call_mount(ctx, action, device->name, NULL, NULL);
 236                 send_block_notification(ctx, action, device->name, device->target);
 237         }
 238         free(path);
 239 }
 240
 241 static int
 242 device_move(struct device *device_o, struct device *device_n)
 243 {
 244         char *path;
 245
 246         if (device_o->autofs != device_n->autofs)
 247                 return -1;
 248
 249         if (device_o->anon || device_n->anon)
 250                 return -1;
 251
 252         if (device_o->autofs) {
 253                 unlink(device_o->target);
 254                 if (asprintf(&path, "/tmp/run/blockd/%s", device_n->name) == -1)
 255                         exit(ENOMEM);
 256
 257                 if (symlink(path, device_n->target))
 258                         ULOG_ERR("failed to symlink %s->%s (%d) - %m\n", device_n->target, path, errno);
 259
 260                 free(path);
 261         } else {
 262                 mkdir(device_n->target, 0755);
 263                 if (mount(device_o->target, device_n->target, NULL, MS_MOVE, NULL))
 264                         rmdir(device_n->target);
 265                 else
 266                         rmdir(device_o->target);
 267         }
 268
 269         return 0;
 270 }
 271
 272 static void vlist_nop_update(struct vlist_tree *tree,
 273                              struct vlist_node *node_new,
 274                              struct vlist_node *node_old)
 275 {
 276 }
 277
 278 VLIST_TREE(devices, avl_strcmp, vlist_nop_update, false, false);
 279
 280 static int
 281 block_hotplug(struct ubus_context *ctx, struct ubus_object *obj,
 282               struct ubus_request_data *req, const char *method,
 283               struct blob_attr *msg)
 284 {
 285         struct blob_attr *data[__MOUNT_MAX];
 286         struct device *device;
 287         struct blob_attr *_msg;
 288         char *devname, *_name;
 289         char *target = NULL, *__target;
 290         char *_target = NULL;
 291
 292         blobmsg_parse(mount_policy, __MOUNT_MAX, data, blob_data(msg), blob_len(msg));
 293
 294         if (!data[MOUNT_DEVICE])
 295                 return UBUS_STATUS_INVALID_ARGUMENT;
 296
 297         devname = blobmsg_get_string(data[MOUNT_DEVICE]);
 298
 299         if (data[MOUNT_TARGET]) {
 300                 target = blobmsg_get_string(data[MOUNT_TARGET]);
 301         } else {
 302                 if (asprintf(&_target, "/mnt/%s",
 303                              blobmsg_get_string(data[MOUNT_DEVICE])) == -1)
 304                         exit(ENOMEM);
 305
 306                 target = _target;
 307         }
 308
 309         if (data[MOUNT_REMOVE])
 310                 device = vlist_find(&devices, devname, device, node);
 311         else
 312                 device = calloc_a(sizeof(*device), &_msg, blob_raw_len(msg),
 313                                   &_name, strlen(devname) + 1, &__target, strlen(target) + 1);
 314
 315         if (!device) {
 316                 if (_target)
 317                         free(_target);
 318
 319                 return UBUS_STATUS_UNKNOWN_ERROR;
 320         }
 321
 322         if (data[MOUNT_REMOVE]) {
 323                 vlist_delete(&devices, &device->node);
 324
 325                 if (device->autofs)
 326                         device_mount_remove(ctx, device);
 327                 else
 328                         free(device);
 329
 330                 if (_target)
 331                         free(_target);
 332         } else {
 333                 struct device *old = vlist_find(&devices, devname, device, node);
 334
 335                 device->autofs = data[MOUNT_AUTOFS] ? blobmsg_get_u32(data[MOUNT_AUTOFS]) : 0;
 336                 device->anon = data[MOUNT_ANON] ? blobmsg_get_u32(data[MOUNT_ANON]) : 0;
 337                 device->msg = _msg;
 338                 memcpy(_msg, msg, blob_raw_len(msg));
 339                 device->name = _name;
 340                 strcpy(_name, devname);
 341                 device->target = __target;
 342                 strcpy(__target, target);
 343                 if (_target)
 344                         free(_target);
 345
 346                 vlist_add(&devices, &device->node, device->name);
 347
 348                 if (old && !device_move(old, device)) {
 349                         if (device->autofs) {
 350                                 device_mount_remove(ctx, old);
 351                                 device_mount_add(ctx, device);
 352                         } else {
 353                                 block("mount", NULL, NULL, 0, NULL);
 354                         }
 355                 } else if (device->autofs) {
 356                         device_mount_add(ctx, device);
 357                 }
 358         }
 359
 360         return 0;
 361 }
 362
 363 static int blockd_mount(struct ubus_context *ctx, struct ubus_object *obj,
 364                         struct ubus_request_data *req, const char *method,
 365                         struct blob_attr *msg)
 366 {
 367         static const char *action = "add";
 368         struct blob_attr *data[__MOUNT_MAX];
 369         struct device *device;
 370         char *devname;
 371
 372         blobmsg_parse(mount_policy, __MOUNT_MAX, data, blob_data(msg), blob_len(msg));
 373
 374         if (!data[MOUNT_DEVICE])
 375                 return UBUS_STATUS_INVALID_ARGUMENT;
 376
 377         devname = blobmsg_get_string(data[MOUNT_DEVICE]);
 378
 379         device = vlist_find(&devices, devname, device, node);
 380         if (!device)
 381                 return UBUS_STATUS_UNKNOWN_ERROR;
 382
 383         hotplug_call_mount(ctx, action, device->name, NULL, NULL);
 384         send_block_notification(ctx, action, device->name, device->target);
 385
 386         return 0;
 387 }
 388
 389 struct blockd_umount_context {
 390         struct ubus_context *ctx;
 391         struct ubus_request_data req;
 392 };
 393
 394 static void blockd_umount_hotplug_cb(struct uloop_process *p, int stat)
 395 {
 396         struct hotplug_context *hctx = container_of(p, struct hotplug_context, process);
 397         struct blockd_umount_context *c = hctx->priv;
 398
 399         ubus_complete_deferred_request(c->ctx, &c->req, 0);
 400
 401         free(c);
 402         free(hctx);
 403 }
 404
 405 static int blockd_umount(struct ubus_context *ctx, struct ubus_object *obj,
 406                          struct ubus_request_data *req, const char *method,
 407                          struct blob_attr *msg)
 408 {
 409         struct blob_attr *data[__MOUNT_MAX];
 410         struct blockd_umount_context *c;
 411         static const char *action = "remove";
 412         char *devname;
 413         static char oldtarget[PATH_MAX];
 414         struct device *device;
 415         int err;
 416
 417         blobmsg_parse(mount_policy, __MOUNT_MAX, data, blob_data(msg), blob_len(msg));
 418
 419         if (!data[MOUNT_DEVICE])
 420                 return UBUS_STATUS_INVALID_ARGUMENT;
 421
 422         devname = blobmsg_get_string(data[MOUNT_DEVICE]);
 423         device = vlist_find(&devices, devname, device, node);
 424         if (device) {
 425                 strncpy(oldtarget, device->target, sizeof(oldtarget)-1);
 426                 oldtarget[PATH_MAX - 1] = '\0';
 427         }
 428
 429         c = calloc(1, sizeof(*c));
 430         if (!c)
 431                 return UBUS_STATUS_UNKNOWN_ERROR;
 432
 433         c->ctx = ctx;
 434         ubus_defer_request(ctx, req, &c->req);
 435
 436         err = hotplug_call_mount(ctx, action, devname, blockd_umount_hotplug_cb, c);
 437         if (err) {
 438                 free(c);
 439                 return UBUS_STATUS_UNKNOWN_ERROR;
 440         }
 441
 442         send_block_notification(ctx, action, devname, oldtarget);
 443
 444         return 0;
 445 }
 446
 447 static void block_info_dump(struct blob_buf *b, struct device *device)
 448 {
 449         struct blob_attr *v;
 450         char *mp;
 451         int rem;
 452
 453         blob_for_each_attr(v, device->msg, rem)
 454                 blobmsg_add_blob(b, v);
 455
 456         mp = _find_mount_point(device->name);
 457         if (mp) {
 458                 blobmsg_add_string(b, "mount", mp);
 459                 free(mp);
 460         } else if (device->autofs && device->target) {
 461                 blobmsg_add_string(b, "mount", device->target);
 462         }
 463 }
 464
 465 static int
 466 block_info(struct ubus_context *ctx, struct ubus_object *obj,
 467            struct ubus_request_data *req, const char *method,
 468            struct blob_attr *msg)
 469 {
 470         struct blob_attr *data[__INFO_MAX];
 471         struct device *device = NULL;
 472
 473         blobmsg_parse(info_policy, __INFO_MAX, data, blob_data(msg), blob_len(msg));
 474
 475         if (data[INFO_DEVICE]) {
 476                 device = vlist_find(&devices, blobmsg_get_string(data[INFO_DEVICE]), device, node);
 477                 if (!device)
 478                         return UBUS_STATUS_INVALID_ARGUMENT;
 479         }
 480
 481         blob_buf_init(&bb, 0);
 482         if (device) {
 483                 block_info_dump(&bb, device);
 484         } else {
 485                 void *a;
 486
 487                 a = blobmsg_open_array(&bb, "devices");
 488                 vlist_for_each_element(&devices, device, node) {
 489                         void *t;
 490
 491                         t = blobmsg_open_table(&bb, "");
 492                         block_info_dump(&bb, device);
 493                         blobmsg_close_table(&bb, t);
 494                 }
 495                 blobmsg_close_array(&bb, a);
 496         }
 497         ubus_send_reply(ctx, req, bb.head);
 498
 499         return 0;
 500 }
 501
 502 static const struct ubus_method block_methods[] = {
 503         UBUS_METHOD("hotplug", block_hotplug, mount_policy),
 504         UBUS_METHOD("mount", blockd_mount, mount_policy),
 505         UBUS_METHOD("umount", blockd_umount, mount_policy),
 506         UBUS_METHOD("info", block_info, info_policy),
 507 };
 508
 509 static struct ubus_object_type block_object_type =
 510         UBUS_OBJECT_TYPE("block", block_methods);
 511
 512 static struct ubus_object block_object = {
 513         .name = "block",
 514         .type = &block_object_type,
 515         .methods = block_methods,
 516         .n_methods = ARRAY_SIZE(block_methods),
 517 };
 518
 519 /* send ubus event for successful mounts, useful for procd triggers */
 520 static int send_block_notification(struct ubus_context *ctx, const char *action,
 521                             const char *devname, const char *target)
 522 {
 523         struct blob_buf buf = { 0 };
 524         char evname[16] = "mount.";
 525         int err;
 526
 527         if (!ctx)
 528                 return -ENXIO;
 529
 530         strncat(evname, action, sizeof(evname) - 1);
 531
 532         blob_buf_init(&buf, 0);
 533
 534         if (devname)
 535                 blobmsg_add_string(&buf, "device", devname);
 536
 537         if (target)
 538                 blobmsg_add_string(&buf, "target", target);
 539
 540         err = ubus_notify(ctx, &block_object, evname, buf.head, -1);
 541
 542         return err;
 543 }
 544
 545 static void
 546 ubus_connect_handler(struct ubus_context *ctx)
 547 {
 548         int ret;
 549
 550         ret = ubus_add_object(ctx, &block_object);
 551         if (ret)
 552                 fprintf(stderr, "Failed to add object: %s\n", ubus_strerror(ret));
 553 }
 554
 555 static int autofs_umount(void)
 556 {
 557         umount2(AUTOFS_MOUNT_PATH, MNT_DETACH);
 558         return 0;
 559 }
 560
 561 static void autofs_read_handler(struct uloop_fd *u, unsigned int events)
 562 {
 563         union autofs_v5_packet_union pktu;
 564         const struct autofs_v5_packet *pkt;
 565         int cmd = AUTOFS_IOC_READY;
 566         struct stat st;
 567
 568         while (read(u->fd, &pktu, sizeof(pktu)) == -1) {
 569                 if (errno != EINTR)
 570                         return;
 571                 continue;
 572         }
 573
 574         if (pktu.hdr.type != autofs_ptype_missing_indirect) {
 575                 ULOG_ERR("unknown packet type %d\n", pktu.hdr.type);
 576                 return;
 577         }
 578
 579         pkt = &pktu.missing_indirect;
 580         ULOG_ERR("kernel is requesting a mount -> %s\n", pkt->name);
 581         if (lstat(pkt->name, &st) == -1)
 582                 if (block("autofs", "add", (char *)pkt->name, 1, NULL))
 583                         cmd = AUTOFS_IOC_FAIL;
 584
 585         if (ioctl(fd_autofs_write, cmd, pkt->wait_queue_token) < 0)
 586                 ULOG_ERR("failed to report back to kernel\n");
 587 }
 588
 589 static void autofs_expire(struct uloop_timeout *t)
 590 {
 591         struct autofs_packet_expire pkt;
 592
 593         while (ioctl(fd_autofs_write, AUTOFS_IOC_EXPIRE, &pkt) == 0)
 594                 block("autofs", "remove", pkt.name, 1, NULL);
 595
 596         uloop_timeout_set(t, AUTOFS_EXPIRE_TIMER);
 597 }
 598
 599 struct uloop_timeout autofs_expire_timer = {
 600         .cb = autofs_expire,
 601 };
 602
 603 static int autofs_mount(void)
 604 {
 605         unsigned long autofs_timeout = AUTOFS_TIMEOUT;
 606         int kproto_version;
 607         int pipefd[2];
 608         char source[64];
 609         char opts[64];
 610
 611         if (pipe(pipefd) < 0) {
 612                 ULOG_ERR("failed to get kernel pipe\n");
 613                 return -1;
 614         }
 615
 616         snprintf(source, sizeof(source), "mountd(pid%u)", getpid());
 617         snprintf(opts, sizeof(opts), "fd=%d,pgrp=%u,minproto=5,maxproto=5", pipefd[1], (unsigned) getpgrp());
 618         mkdir(AUTOFS_MOUNT_PATH, 0555);
 619         if (mount(source, AUTOFS_MOUNT_PATH, "autofs", 0, opts)) {
 620                 ULOG_ERR("unable to mount autofs on %s\n", AUTOFS_MOUNT_PATH);
 621                 close(pipefd[0]);
 622                 close(pipefd[1]);
 623                 return -1;
 624         }
 625         close(pipefd[1]);
 626         fd_autofs_read.fd = pipefd[0];
 627         fd_autofs_read.cb = autofs_read_handler;
 628         uloop_fd_add(&fd_autofs_read, ULOOP_READ);
 629
 630         fd_autofs_write = open(AUTOFS_MOUNT_PATH, O_RDONLY);
 631         if(fd_autofs_write < 0) {
 632                 autofs_umount();
 633                 ULOG_ERR("failed to open direcory\n");
 634                 return -1;
 635         }
 636
 637         ioctl(fd_autofs_write, AUTOFS_IOC_PROTOVER, &kproto_version);
 638         if (kproto_version != 5) {
 639                 ULOG_ERR("only kernel protocol version 5 is tested. You have %d.\n",
 640                         kproto_version);
 641                 exit(EXIT_FAILURE);
 642         }
 643         if (ioctl(fd_autofs_write, AUTOFS_IOC_SETTIMEOUT, &autofs_timeout))
 644                 ULOG_ERR("failed to set autofs timeout\n");
 645
 646         uloop_timeout_set(&autofs_expire_timer, AUTOFS_EXPIRE_TIMER);
 647
 648         fcntl(fd_autofs_write, F_SETFD, fcntl(fd_autofs_write, F_GETFD) | FD_CLOEXEC);
 649         fcntl(fd_autofs_read.fd, F_SETFD, fcntl(fd_autofs_read.fd, F_GETFD) | FD_CLOEXEC);
 650
 651         return 0;
 652 }
 653
 654 static void blockd_startup_cb(struct uloop_process *p, int stat)
 655 {
 656         send_block_notification(&conn.ctx, "ready", NULL, NULL);
 657 }
 658
 659 static struct uloop_process startup_process = {
 660         .cb = blockd_startup_cb,
 661 };
 662
 663 static void blockd_startup(struct uloop_timeout *t)
 664 {
 665         block("autofs", "start", NULL, 0, &startup_process);
 666 }
 667
 668 struct uloop_timeout startup = {
 669         .cb = blockd_startup,
 670 };
 671
 672 int main(int argc, char **argv)
 673 {
 674         /* make sure blockd is in it's own POSIX process group */
 675         setpgrp();
 676
 677         ulog_open(ULOG_SYSLOG | ULOG_STDIO, LOG_DAEMON, "blockd");
 678         uloop_init();
 679
 680         autofs_mount();
 681
 682         conn.cb = ubus_connect_handler;
 683         ubus_auto_connect(&conn);
 684
 685         uloop_timeout_set(&startup, 1000);
 686
 687         uloop_run();
 688         uloop_done();
 689
 690         autofs_umount();
 691
 692         vlist_flush_all(&devices);
 693
 694         return 0;
 695 }