blockd.c

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