blockd.c

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