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