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;
 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         if (symlink(path, device->target))
 224                 ULOG_ERR("failed to symlink %s->%s (%d) - %m\n", device->target, path, errno);
 225         else
 226                 hotplug_call_mount(ctx, "add", device->name, NULL, NULL);
 227
 228         free(path);
 229 }
 230
 231 static int
 232 device_move(struct device *device_o, struct device *device_n)
 233 {
 234         char *path;
 235
 236         if (device_o->autofs != device_n->autofs)
 237                 return -1;
 238
 239         if (device_o->anon || device_n->anon)
 240                 return -1;
 241
 242         if (device_o->autofs) {
 243                 unlink(device_o->target);
 244                 if (asprintf(&path, "/tmp/run/blockd/%s", device_n->name) == -1)
 245                         exit(ENOMEM);
 246
 247                 if (symlink(path, device_n->target))
 248                         ULOG_ERR("failed to symlink %s->%s (%d) - %m\n", device_n->target, path, errno);
 249
 250                 free(path);
 251         } else {
 252                 mkdir(device_n->target, 0755);
 253                 if (mount(device_o->target, device_n->target, NULL, MS_MOVE, NULL))
 254                         rmdir(device_n->target);
 255                 else
 256                         rmdir(device_o->target);
 257         }
 258
 259         return 0;
 260 }
 261
 262 static void vlist_nop_update(struct vlist_tree *tree,
 263                              struct vlist_node *node_new,
 264                              struct vlist_node *node_old)
 265 {
 266 }
 267
 268 VLIST_TREE(devices, avl_strcmp, vlist_nop_update, false, false);
 269
 270 static int
 271 block_hotplug(struct ubus_context *ctx, struct ubus_object *obj,
 272               struct ubus_request_data *req, const char *method,
 273               struct blob_attr *msg)
 274 {
 275         struct blob_attr *data[__MOUNT_MAX];
 276         struct device *device;
 277         struct blob_attr *_msg;
 278         char *devname, *_name;
 279         char *target = NULL, *__target;
 280         char *_target = NULL;
 281
 282         blobmsg_parse(mount_policy, __MOUNT_MAX, data, blob_data(msg), blob_len(msg));
 283
 284         if (!data[MOUNT_DEVICE])
 285                 return UBUS_STATUS_INVALID_ARGUMENT;
 286
 287         devname = blobmsg_get_string(data[MOUNT_DEVICE]);
 288
 289         if (data[MOUNT_TARGET]) {
 290                 target = blobmsg_get_string(data[MOUNT_TARGET]);
 291         } else {
 292                 if (asprintf(&_target, "/mnt/%s",
 293                              blobmsg_get_string(data[MOUNT_DEVICE])) == -1)
 294                         exit(ENOMEM);
 295
 296                 target = _target;
 297         }
 298
 299         if (data[MOUNT_REMOVE])
 300                 device = vlist_find(&devices, devname, device, node);
 301         else
 302                 device = calloc_a(sizeof(*device), &_msg, blob_raw_len(msg),
 303                                   &_name, strlen(devname) + 1, &__target, strlen(target) + 1);
 304
 305         if (!device) {
 306                 if (_target)
 307                         free(_target);
 308
 309                 return UBUS_STATUS_UNKNOWN_ERROR;
 310         }
 311
 312         if (data[MOUNT_REMOVE]) {
 313                 vlist_delete(&devices, &device->node);
 314
 315                 if (device->autofs)
 316                         device_mount_remove(ctx, device);
 317                 else
 318                         free(device);
 319
 320                 if (_target)
 321                         free(_target);
 322         } else {
 323                 struct device *old = vlist_find(&devices, devname, device, node);
 324
 325                 device->autofs = data[MOUNT_AUTOFS] ? blobmsg_get_u32(data[MOUNT_AUTOFS]) : 0;
 326                 device->anon = data[MOUNT_ANON] ? blobmsg_get_u32(data[MOUNT_ANON]) : 0;
 327                 device->msg = _msg;
 328                 memcpy(_msg, msg, blob_raw_len(msg));
 329                 device->name = _name;
 330                 strcpy(_name, devname);
 331                 device->target = __target;
 332                 strcpy(__target, target);
 333                 if (_target)
 334                         free(_target);
 335
 336                 vlist_add(&devices, &device->node, device->name);
 337
 338                 if (old && !device_move(old, device)) {
 339                         if (device->autofs) {
 340                                 device_mount_remove(ctx, old);
 341                                 device_mount_add(ctx, device);
 342                         } else {
 343                                 block("mount", NULL, NULL);
 344                         }
 345                 } else if (device->autofs) {
 346                         device_mount_add(ctx, device);
 347                 }
 348         }
 349
 350         return 0;
 351 }
 352
 353 static int blockd_mount(struct ubus_context *ctx, struct ubus_object *obj,
 354                         struct ubus_request_data *req, const char *method,
 355                         struct blob_attr *msg)
 356 {
 357         struct blob_attr *data[__MOUNT_MAX];
 358         struct device *device;
 359         char *devname;
 360
 361         blobmsg_parse(mount_policy, __MOUNT_MAX, data, blob_data(msg), blob_len(msg));
 362
 363         if (!data[MOUNT_DEVICE])
 364                 return UBUS_STATUS_INVALID_ARGUMENT;
 365
 366         devname = blobmsg_get_string(data[MOUNT_DEVICE]);
 367
 368         device = vlist_find(&devices, devname, device, node);
 369         if (!device)
 370                 return UBUS_STATUS_UNKNOWN_ERROR;
 371
 372         hotplug_call_mount(ctx, "add", device->name, NULL, NULL);
 373
 374         return 0;
 375 }
 376
 377 struct blockd_umount_context {
 378         struct ubus_context *ctx;
 379         struct ubus_request_data req;
 380 };
 381
 382 static void blockd_umount_hotplug_cb(struct uloop_process *p, int stat)
 383 {
 384         struct hotplug_context *hctx = container_of(p, struct hotplug_context, process);
 385         struct blockd_umount_context *c = hctx->priv;
 386
 387         ubus_complete_deferred_request(c->ctx, &c->req, 0);
 388
 389         free(c);
 390         free(hctx);
 391 }
 392
 393 static int blockd_umount(struct ubus_context *ctx, struct ubus_object *obj,
 394                          struct ubus_request_data *req, const char *method,
 395                          struct blob_attr *msg)
 396 {
 397         struct blob_attr *data[__MOUNT_MAX];
 398         struct blockd_umount_context *c;
 399         char *devname;
 400         int err;
 401
 402         blobmsg_parse(mount_policy, __MOUNT_MAX, data, blob_data(msg), blob_len(msg));
 403
 404         if (!data[MOUNT_DEVICE])
 405                 return UBUS_STATUS_INVALID_ARGUMENT;
 406
 407         devname = blobmsg_get_string(data[MOUNT_DEVICE]);
 408
 409         c = calloc(1, sizeof(*c));
 410         if (!c)
 411                 return UBUS_STATUS_UNKNOWN_ERROR;
 412
 413         c->ctx = ctx;
 414         ubus_defer_request(ctx, req, &c->req);
 415
 416         err = hotplug_call_mount(ctx, "remove", devname, blockd_umount_hotplug_cb, c);
 417         if (err) {
 418                 free(c);
 419                 return UBUS_STATUS_UNKNOWN_ERROR;
 420         }
 421
 422         return 0;
 423 }
 424
 425 static void block_info_dump(struct blob_buf *b, struct device *device)
 426 {
 427         struct blob_attr *v;
 428         char *mp;
 429         int rem;
 430
 431         blob_for_each_attr(v, device->msg, rem)
 432                 blobmsg_add_blob(b, v);
 433
 434         mp = _find_mount_point(device->name);
 435         if (mp) {
 436                 blobmsg_add_string(b, "mount", mp);
 437                 free(mp);
 438         } else if (device->autofs && device->target) {
 439                 blobmsg_add_string(b, "mount", device->target);
 440         }
 441 }
 442
 443 static int
 444 block_info(struct ubus_context *ctx, struct ubus_object *obj,
 445            struct ubus_request_data *req, const char *method,
 446            struct blob_attr *msg)
 447 {
 448         struct blob_attr *data[__INFO_MAX];
 449         struct device *device = NULL;
 450
 451         blobmsg_parse(info_policy, __INFO_MAX, data, blob_data(msg), blob_len(msg));
 452
 453         if (data[INFO_DEVICE]) {
 454                 device = vlist_find(&devices, blobmsg_get_string(data[INFO_DEVICE]), device, node);
 455                 if (!device)
 456                         return UBUS_STATUS_INVALID_ARGUMENT;
 457         }
 458
 459         blob_buf_init(&bb, 0);
 460         if (device) {
 461                 block_info_dump(&bb, device);
 462         } else {
 463                 void *a;
 464
 465                 a = blobmsg_open_array(&bb, "devices");
 466                 vlist_for_each_element(&devices, device, node) {
 467                         void *t;
 468
 469                         t = blobmsg_open_table(&bb, "");
 470                         block_info_dump(&bb, device);
 471                         blobmsg_close_table(&bb, t);
 472                 }
 473                 blobmsg_close_array(&bb, a);
 474         }
 475         ubus_send_reply(ctx, req, bb.head);
 476
 477         return 0;
 478 }
 479
 480 static const struct ubus_method block_methods[] = {
 481         UBUS_METHOD("hotplug", block_hotplug, mount_policy),
 482         UBUS_METHOD("mount", blockd_mount, mount_policy),
 483         UBUS_METHOD("umount", blockd_umount, mount_policy),
 484         UBUS_METHOD("info", block_info, info_policy),
 485 };
 486
 487 static struct ubus_object_type block_object_type =
 488         UBUS_OBJECT_TYPE("block", block_methods);
 489
 490 static struct ubus_object block_object = {
 491         .name = "block",
 492         .type = &block_object_type,
 493         .methods = block_methods,
 494         .n_methods = ARRAY_SIZE(block_methods),
 495 };
 496
 497 /* send ubus event for successful mounts, useful for procd triggers */
 498 static int send_block_notification(struct ubus_context *ctx, const char *action,
 499                             const char *devname)
 500 {
 501         struct blob_buf buf = { 0 };
 502         char evname[16] = "mount.";
 503         int err;
 504
 505         if (!ctx)
 506                 return -ENXIO;
 507
 508         strncat(evname, action, sizeof(evname) - 1);
 509
 510         blob_buf_init(&buf, 0);
 511         blobmsg_add_string(&buf, "devname", devname);
 512
 513         err = ubus_notify(ctx, &block_object, evname, buf.head, -1);
 514
 515         return err;
 516 }
 517
 518 static void
 519 ubus_connect_handler(struct ubus_context *ctx)
 520 {
 521         int ret;
 522
 523         ret = ubus_add_object(ctx, &block_object);
 524         if (ret)
 525                 fprintf(stderr, "Failed to add object: %s\n", ubus_strerror(ret));
 526 }
 527
 528 static int autofs_umount(void)
 529 {
 530         umount2(AUTOFS_MOUNT_PATH, MNT_DETACH);
 531         return 0;
 532 }
 533
 534 static void autofs_read_handler(struct uloop_fd *u, unsigned int events)
 535 {
 536         union autofs_v5_packet_union pktu;
 537         const struct autofs_v5_packet *pkt;
 538         int cmd = AUTOFS_IOC_READY;
 539         struct stat st;
 540
 541         while (read(u->fd, &pktu, sizeof(pktu)) == -1) {
 542                 if (errno != EINTR)
 543                         return;
 544                 continue;
 545         }
 546
 547         if (pktu.hdr.type != autofs_ptype_missing_indirect) {
 548                 ULOG_ERR("unknown packet type %d\n", pktu.hdr.type);
 549                 return;
 550         }
 551
 552         pkt = &pktu.missing_indirect;
 553         ULOG_ERR("kernel is requesting a mount -> %s\n", pkt->name);
 554         if (lstat(pkt->name, &st) == -1)
 555                 if (block("autofs", "add", (char *)pkt->name))
 556                         cmd = AUTOFS_IOC_FAIL;
 557
 558         if (ioctl(fd_autofs_write, cmd, pkt->wait_queue_token) < 0)
 559                 ULOG_ERR("failed to report back to kernel\n");
 560 }
 561
 562 static void autofs_expire(struct uloop_timeout *t)
 563 {
 564         struct autofs_packet_expire pkt;
 565
 566         while (ioctl(fd_autofs_write, AUTOFS_IOC_EXPIRE, &pkt) == 0)
 567                 block("autofs", "remove", pkt.name);
 568
 569         uloop_timeout_set(t, AUTOFS_EXPIRE_TIMER);
 570 }
 571
 572 struct uloop_timeout autofs_expire_timer = {
 573         .cb = autofs_expire,
 574 };
 575
 576 static int autofs_mount(void)
 577 {
 578         int autofs_timeout = AUTOFS_TIMEOUT;
 579         int kproto_version;
 580         int pipefd[2];
 581         char source[64];
 582         char opts[64];
 583
 584         if (pipe(pipefd) < 0) {
 585                 ULOG_ERR("failed to get kernel pipe\n");
 586                 return -1;
 587         }
 588
 589         snprintf(source, sizeof(source), "mountd(pid%u)", getpid());
 590         snprintf(opts, sizeof(opts), "fd=%d,pgrp=%u,minproto=5,maxproto=5", pipefd[1], (unsigned) getpgrp());
 591         mkdir(AUTOFS_MOUNT_PATH, 0555);
 592         if (mount(source, AUTOFS_MOUNT_PATH, "autofs", 0, opts)) {
 593                 ULOG_ERR("unable to mount autofs on %s\n", AUTOFS_MOUNT_PATH);
 594                 close(pipefd[0]);
 595                 close(pipefd[1]);
 596                 return -1;
 597         }
 598         close(pipefd[1]);
 599         fd_autofs_read.fd = pipefd[0];
 600         fd_autofs_read.cb = autofs_read_handler;
 601         uloop_fd_add(&fd_autofs_read, ULOOP_READ);
 602
 603         fd_autofs_write = open(AUTOFS_MOUNT_PATH, O_RDONLY);
 604         if(fd_autofs_write < 0) {
 605                 autofs_umount();
 606                 ULOG_ERR("failed to open direcory\n");
 607                 return -1;
 608         }
 609
 610         ioctl(fd_autofs_write, AUTOFS_IOC_PROTOVER, &kproto_version);
 611         if (kproto_version != 5) {
 612                 ULOG_ERR("only kernel protocol version 5 is tested. You have %d.\n",
 613                         kproto_version);
 614                 exit(EXIT_FAILURE);
 615         }
 616         if (ioctl(fd_autofs_write, AUTOFS_IOC_SETTIMEOUT, &autofs_timeout))
 617                 ULOG_ERR("failed to set autofs timeout\n");
 618
 619         uloop_timeout_set(&autofs_expire_timer, AUTOFS_EXPIRE_TIMER);
 620
 621         fcntl(fd_autofs_write, F_SETFD, fcntl(fd_autofs_write, F_GETFD) | FD_CLOEXEC);
 622         fcntl(fd_autofs_read.fd, F_SETFD, fcntl(fd_autofs_read.fd, F_GETFD) | FD_CLOEXEC);
 623
 624         return 0;
 625 }
 626
 627 static void blockd_startup(struct uloop_timeout *t)
 628 {
 629         block("autofs", "start", NULL);
 630 }
 631
 632 struct uloop_timeout startup = {
 633         .cb = blockd_startup,
 634 };
 635
 636 int main(int argc, char **argv)
 637 {
 638         ulog_open(ULOG_SYSLOG | ULOG_STDIO, LOG_DAEMON, "blockd");
 639         uloop_init();
 640
 641         autofs_mount();
 642
 643         conn.cb = ubus_connect_handler;
 644         ubus_auto_connect(&conn);
 645
 646         uloop_timeout_set(&startup, 1000);
 647
 648         uloop_run();
 649         uloop_done();
 650
 651         autofs_umount();
 652
 653         vlist_flush_all(&devices);
 654
 655         return 0;
 656 }