1 /* SPDX-License-Identifier: GPL-2.0 */ 2 3 #include <linux/compiler_types.h> 4 #include <linux/errno.h> 5 #include <linux/fs.h> 6 #include <linux/fsnotify.h> 7 #include <linux/gfp.h> 8 #include <linux/idr.h> 9 #include <linux/init.h> 10 #include <linux/ipc_namespace.h> 11 #include <linux/kdev_t.h> 12 #include <linux/kernel.h> 13 #include <linux/list.h> 14 #include <linux/namei.h> 15 #include <linux/magic.h> 16 #include <linux/major.h> 17 #include <linux/miscdevice.h> 18 #include <linux/module.h> 19 #include <linux/mutex.h> 20 #include <linux/mount.h> 21 #include <linux/parser.h> 22 #include <linux/radix-tree.h> 23 #include <linux/sched.h> 24 #include <linux/seq_file.h> 25 #include <linux/slab.h> 26 #include <linux/spinlock_types.h> 27 #include <linux/stddef.h> 28 #include <linux/string.h> 29 #include <linux/types.h> 30 #include <linux/uaccess.h> 31 #include <linux/user_namespace.h> 32 #include <linux/xarray.h> 33 #include <uapi/asm-generic/errno-base.h> 34 #include <uapi/linux/android/binder.h> 35 #include <uapi/linux/android/binderfs.h> 36 37 #include "binder_internal.h" 38 39 #define FIRST_INODE 1 40 #define SECOND_INODE 2 41 #define INODE_OFFSET 3 42 #define INTSTRLEN 21 43 #define BINDERFS_MAX_MINOR (1U << MINORBITS) 44 /* Ensure that the initial ipc namespace always has devices available. */ 45 #define BINDERFS_MAX_MINOR_CAPPED (BINDERFS_MAX_MINOR - 4) 46 47 static dev_t binderfs_dev; 48 static DEFINE_MUTEX(binderfs_minors_mutex); 49 static DEFINE_IDA(binderfs_minors); 50 51 enum { 52 Opt_max, 53 Opt_stats_mode, 54 Opt_err 55 }; 56 57 enum binderfs_stats_mode { 58 STATS_NONE, 59 STATS_GLOBAL, 60 }; 61 62 static const match_table_t tokens = { 63 { Opt_max, "max=%d" }, 64 { Opt_stats_mode, "stats=%s" }, 65 { Opt_err, NULL } 66 }; 67 68 static inline struct binderfs_info *BINDERFS_I(const struct inode *inode) 69 { 70 return inode->i_sb->s_fs_info; 71 } 72 73 bool is_binderfs_device(const struct inode *inode) 74 { 75 if (inode->i_sb->s_magic == BINDERFS_SUPER_MAGIC) 76 return true; 77 78 return false; 79 } 80 81 /** 82 * binderfs_binder_device_create - allocate inode from super block of a 83 * binderfs mount 84 * @ref_inode: inode from wich the super block will be taken 85 * @userp: buffer to copy information about new device for userspace to 86 * @req: struct binderfs_device as copied from userspace 87 * 88 * This function allocates a new binder_device and reserves a new minor 89 * number for it. 90 * Minor numbers are limited and tracked globally in binderfs_minors. The 91 * function will stash a struct binder_device for the specific binder 92 * device in i_private of the inode. 93 * It will go on to allocate a new inode from the super block of the 94 * filesystem mount, stash a struct binder_device in its i_private field 95 * and attach a dentry to that inode. 96 * 97 * Return: 0 on success, negative errno on failure 98 */ 99 static int binderfs_binder_device_create(struct inode *ref_inode, 100 struct binderfs_device __user *userp, 101 struct binderfs_device *req) 102 { 103 int minor, ret; 104 struct dentry *dentry, *root; 105 struct binder_device *device; 106 char *name = NULL; 107 size_t name_len; 108 struct inode *inode = NULL; 109 struct super_block *sb = ref_inode->i_sb; 110 struct binderfs_info *info = sb->s_fs_info; 111 #if defined(CONFIG_IPC_NS) 112 bool use_reserve = (info->ipc_ns == &init_ipc_ns); 113 #else 114 bool use_reserve = true; 115 #endif 116 117 /* Reserve new minor number for the new device. */ 118 mutex_lock(&binderfs_minors_mutex); 119 if (++info->device_count <= info->mount_opts.max) 120 minor = ida_alloc_max(&binderfs_minors, 121 use_reserve ? BINDERFS_MAX_MINOR : 122 BINDERFS_MAX_MINOR_CAPPED, 123 GFP_KERNEL); 124 else 125 minor = -ENOSPC; 126 if (minor < 0) { 127 --info->device_count; 128 mutex_unlock(&binderfs_minors_mutex); 129 return minor; 130 } 131 mutex_unlock(&binderfs_minors_mutex); 132 133 ret = -ENOMEM; 134 device = kzalloc(sizeof(*device), GFP_KERNEL); 135 if (!device) 136 goto err; 137 138 inode = new_inode(sb); 139 if (!inode) 140 goto err; 141 142 inode->i_ino = minor + INODE_OFFSET; 143 inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode); 144 init_special_inode(inode, S_IFCHR | 0600, 145 MKDEV(MAJOR(binderfs_dev), minor)); 146 inode->i_fop = &binder_fops; 147 inode->i_uid = info->root_uid; 148 inode->i_gid = info->root_gid; 149 150 req->name[BINDERFS_MAX_NAME] = '\0'; /* NUL-terminate */ 151 name_len = strlen(req->name); 152 /* Make sure to include terminating NUL byte */ 153 name = kmemdup(req->name, name_len + 1, GFP_KERNEL); 154 if (!name) 155 goto err; 156 157 refcount_set(&device->ref, 1); 158 device->binderfs_inode = inode; 159 device->context.binder_context_mgr_uid = INVALID_UID; 160 device->context.name = name; 161 device->miscdev.name = name; 162 device->miscdev.minor = minor; 163 mutex_init(&device->context.context_mgr_node_lock); 164 165 req->major = MAJOR(binderfs_dev); 166 req->minor = minor; 167 168 if (userp && copy_to_user(userp, req, sizeof(*req))) { 169 ret = -EFAULT; 170 goto err; 171 } 172 173 root = sb->s_root; 174 inode_lock(d_inode(root)); 175 176 /* look it up */ 177 dentry = lookup_one_len(name, root, name_len); 178 if (IS_ERR(dentry)) { 179 inode_unlock(d_inode(root)); 180 ret = PTR_ERR(dentry); 181 goto err; 182 } 183 184 if (d_really_is_positive(dentry)) { 185 /* already exists */ 186 dput(dentry); 187 inode_unlock(d_inode(root)); 188 ret = -EEXIST; 189 goto err; 190 } 191 192 inode->i_private = device; 193 d_instantiate(dentry, inode); 194 fsnotify_create(root->d_inode, dentry); 195 inode_unlock(d_inode(root)); 196 197 return 0; 198 199 err: 200 kfree(name); 201 kfree(device); 202 mutex_lock(&binderfs_minors_mutex); 203 --info->device_count; 204 ida_free(&binderfs_minors, minor); 205 mutex_unlock(&binderfs_minors_mutex); 206 iput(inode); 207 208 return ret; 209 } 210 211 /** 212 * binderfs_ctl_ioctl - handle binder device node allocation requests 213 * 214 * The request handler for the binder-control device. All requests operate on 215 * the binderfs mount the binder-control device resides in: 216 * - BINDER_CTL_ADD 217 * Allocate a new binder device. 218 * 219 * Return: 0 on success, negative errno on failure 220 */ 221 static long binder_ctl_ioctl(struct file *file, unsigned int cmd, 222 unsigned long arg) 223 { 224 int ret = -EINVAL; 225 struct inode *inode = file_inode(file); 226 struct binderfs_device __user *device = (struct binderfs_device __user *)arg; 227 struct binderfs_device device_req; 228 229 switch (cmd) { 230 case BINDER_CTL_ADD: 231 ret = copy_from_user(&device_req, device, sizeof(device_req)); 232 if (ret) { 233 ret = -EFAULT; 234 break; 235 } 236 237 ret = binderfs_binder_device_create(inode, device, &device_req); 238 break; 239 default: 240 break; 241 } 242 243 return ret; 244 } 245 246 static void binderfs_evict_inode(struct inode *inode) 247 { 248 struct binder_device *device = inode->i_private; 249 struct binderfs_info *info = BINDERFS_I(inode); 250 251 clear_inode(inode); 252 253 if (!S_ISCHR(inode->i_mode) || !device) 254 return; 255 256 mutex_lock(&binderfs_minors_mutex); 257 --info->device_count; 258 ida_free(&binderfs_minors, device->miscdev.minor); 259 mutex_unlock(&binderfs_minors_mutex); 260 261 if (refcount_dec_and_test(&device->ref)) { 262 kfree(device->context.name); 263 kfree(device); 264 } 265 } 266 267 /** 268 * binderfs_parse_mount_opts - parse binderfs mount options 269 * @data: options to set (can be NULL in which case defaults are used) 270 */ 271 static int binderfs_parse_mount_opts(char *data, 272 struct binderfs_mount_opts *opts) 273 { 274 char *p, *stats; 275 opts->max = BINDERFS_MAX_MINOR; 276 opts->stats_mode = STATS_NONE; 277 278 while ((p = strsep(&data, ",")) != NULL) { 279 substring_t args[MAX_OPT_ARGS]; 280 int token; 281 int max_devices; 282 283 if (!*p) 284 continue; 285 286 token = match_token(p, tokens, args); 287 switch (token) { 288 case Opt_max: 289 if (match_int(&args[0], &max_devices) || 290 (max_devices < 0 || 291 (max_devices > BINDERFS_MAX_MINOR))) 292 return -EINVAL; 293 294 opts->max = max_devices; 295 break; 296 case Opt_stats_mode: 297 if (!capable(CAP_SYS_ADMIN)) 298 return -EINVAL; 299 300 stats = match_strdup(&args[0]); 301 if (!stats) 302 return -ENOMEM; 303 304 if (strcmp(stats, "global") != 0) { 305 kfree(stats); 306 return -EINVAL; 307 } 308 309 opts->stats_mode = STATS_GLOBAL; 310 kfree(stats); 311 break; 312 default: 313 pr_err("Invalid mount options\n"); 314 return -EINVAL; 315 } 316 } 317 318 return 0; 319 } 320 321 static int binderfs_remount(struct super_block *sb, int *flags, char *data) 322 { 323 int prev_stats_mode, ret; 324 struct binderfs_info *info = sb->s_fs_info; 325 326 prev_stats_mode = info->mount_opts.stats_mode; 327 ret = binderfs_parse_mount_opts(data, &info->mount_opts); 328 if (ret) 329 return ret; 330 331 if (prev_stats_mode != info->mount_opts.stats_mode) { 332 pr_err("Binderfs stats mode cannot be changed during a remount\n"); 333 info->mount_opts.stats_mode = prev_stats_mode; 334 return -EINVAL; 335 } 336 337 return 0; 338 } 339 340 static int binderfs_show_mount_opts(struct seq_file *seq, struct dentry *root) 341 { 342 struct binderfs_info *info; 343 344 info = root->d_sb->s_fs_info; 345 if (info->mount_opts.max <= BINDERFS_MAX_MINOR) 346 seq_printf(seq, ",max=%d", info->mount_opts.max); 347 if (info->mount_opts.stats_mode == STATS_GLOBAL) 348 seq_printf(seq, ",stats=global"); 349 350 return 0; 351 } 352 353 static const struct super_operations binderfs_super_ops = { 354 .evict_inode = binderfs_evict_inode, 355 .remount_fs = binderfs_remount, 356 .show_options = binderfs_show_mount_opts, 357 .statfs = simple_statfs, 358 }; 359 360 static inline bool is_binderfs_control_device(const struct dentry *dentry) 361 { 362 struct binderfs_info *info = dentry->d_sb->s_fs_info; 363 return info->control_dentry == dentry; 364 } 365 366 static int binderfs_rename(struct inode *old_dir, struct dentry *old_dentry, 367 struct inode *new_dir, struct dentry *new_dentry, 368 unsigned int flags) 369 { 370 if (is_binderfs_control_device(old_dentry) || 371 is_binderfs_control_device(new_dentry)) 372 return -EPERM; 373 374 return simple_rename(old_dir, old_dentry, new_dir, new_dentry, flags); 375 } 376 377 static int binderfs_unlink(struct inode *dir, struct dentry *dentry) 378 { 379 if (is_binderfs_control_device(dentry)) 380 return -EPERM; 381 382 return simple_unlink(dir, dentry); 383 } 384 385 static const struct file_operations binder_ctl_fops = { 386 .owner = THIS_MODULE, 387 .open = nonseekable_open, 388 .unlocked_ioctl = binder_ctl_ioctl, 389 .compat_ioctl = binder_ctl_ioctl, 390 .llseek = noop_llseek, 391 }; 392 393 /** 394 * binderfs_binder_ctl_create - create a new binder-control device 395 * @sb: super block of the binderfs mount 396 * 397 * This function creates a new binder-control device node in the binderfs mount 398 * referred to by @sb. 399 * 400 * Return: 0 on success, negative errno on failure 401 */ 402 static int binderfs_binder_ctl_create(struct super_block *sb) 403 { 404 int minor, ret; 405 struct dentry *dentry; 406 struct binder_device *device; 407 struct inode *inode = NULL; 408 struct dentry *root = sb->s_root; 409 struct binderfs_info *info = sb->s_fs_info; 410 #if defined(CONFIG_IPC_NS) 411 bool use_reserve = (info->ipc_ns == &init_ipc_ns); 412 #else 413 bool use_reserve = true; 414 #endif 415 416 device = kzalloc(sizeof(*device), GFP_KERNEL); 417 if (!device) 418 return -ENOMEM; 419 420 /* If we have already created a binder-control node, return. */ 421 if (info->control_dentry) { 422 ret = 0; 423 goto out; 424 } 425 426 ret = -ENOMEM; 427 inode = new_inode(sb); 428 if (!inode) 429 goto out; 430 431 /* Reserve a new minor number for the new device. */ 432 mutex_lock(&binderfs_minors_mutex); 433 minor = ida_alloc_max(&binderfs_minors, 434 use_reserve ? BINDERFS_MAX_MINOR : 435 BINDERFS_MAX_MINOR_CAPPED, 436 GFP_KERNEL); 437 mutex_unlock(&binderfs_minors_mutex); 438 if (minor < 0) { 439 ret = minor; 440 goto out; 441 } 442 443 inode->i_ino = SECOND_INODE; 444 inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode); 445 init_special_inode(inode, S_IFCHR | 0600, 446 MKDEV(MAJOR(binderfs_dev), minor)); 447 inode->i_fop = &binder_ctl_fops; 448 inode->i_uid = info->root_uid; 449 inode->i_gid = info->root_gid; 450 451 device->binderfs_inode = inode; 452 device->miscdev.minor = minor; 453 454 dentry = d_alloc_name(root, "binder-control"); 455 if (!dentry) 456 goto out; 457 458 inode->i_private = device; 459 info->control_dentry = dentry; 460 d_add(dentry, inode); 461 462 return 0; 463 464 out: 465 kfree(device); 466 iput(inode); 467 468 return ret; 469 } 470 471 static const struct inode_operations binderfs_dir_inode_operations = { 472 .lookup = simple_lookup, 473 .rename = binderfs_rename, 474 .unlink = binderfs_unlink, 475 }; 476 477 static struct inode *binderfs_make_inode(struct super_block *sb, int mode) 478 { 479 struct inode *ret; 480 481 ret = new_inode(sb); 482 if (ret) { 483 ret->i_ino = iunique(sb, BINDERFS_MAX_MINOR + INODE_OFFSET); 484 ret->i_mode = mode; 485 ret->i_atime = ret->i_mtime = ret->i_ctime = current_time(ret); 486 } 487 return ret; 488 } 489 490 static struct dentry *binderfs_create_dentry(struct dentry *parent, 491 const char *name) 492 { 493 struct dentry *dentry; 494 495 dentry = lookup_one_len(name, parent, strlen(name)); 496 if (IS_ERR(dentry)) 497 return dentry; 498 499 /* Return error if the file/dir already exists. */ 500 if (d_really_is_positive(dentry)) { 501 dput(dentry); 502 return ERR_PTR(-EEXIST); 503 } 504 505 return dentry; 506 } 507 508 void binderfs_remove_file(struct dentry *dentry) 509 { 510 struct inode *parent_inode; 511 512 parent_inode = d_inode(dentry->d_parent); 513 inode_lock(parent_inode); 514 if (simple_positive(dentry)) { 515 dget(dentry); 516 simple_unlink(parent_inode, dentry); 517 d_delete(dentry); 518 dput(dentry); 519 } 520 inode_unlock(parent_inode); 521 } 522 523 struct dentry *binderfs_create_file(struct dentry *parent, const char *name, 524 const struct file_operations *fops, 525 void *data) 526 { 527 struct dentry *dentry; 528 struct inode *new_inode, *parent_inode; 529 struct super_block *sb; 530 531 parent_inode = d_inode(parent); 532 inode_lock(parent_inode); 533 534 dentry = binderfs_create_dentry(parent, name); 535 if (IS_ERR(dentry)) 536 goto out; 537 538 sb = parent_inode->i_sb; 539 new_inode = binderfs_make_inode(sb, S_IFREG | 0444); 540 if (!new_inode) { 541 dput(dentry); 542 dentry = ERR_PTR(-ENOMEM); 543 goto out; 544 } 545 546 new_inode->i_fop = fops; 547 new_inode->i_private = data; 548 d_instantiate(dentry, new_inode); 549 fsnotify_create(parent_inode, dentry); 550 551 out: 552 inode_unlock(parent_inode); 553 return dentry; 554 } 555 556 static struct dentry *binderfs_create_dir(struct dentry *parent, 557 const char *name) 558 { 559 struct dentry *dentry; 560 struct inode *new_inode, *parent_inode; 561 struct super_block *sb; 562 563 parent_inode = d_inode(parent); 564 inode_lock(parent_inode); 565 566 dentry = binderfs_create_dentry(parent, name); 567 if (IS_ERR(dentry)) 568 goto out; 569 570 sb = parent_inode->i_sb; 571 new_inode = binderfs_make_inode(sb, S_IFDIR | 0755); 572 if (!new_inode) { 573 dput(dentry); 574 dentry = ERR_PTR(-ENOMEM); 575 goto out; 576 } 577 578 new_inode->i_fop = &simple_dir_operations; 579 new_inode->i_op = &simple_dir_inode_operations; 580 581 set_nlink(new_inode, 2); 582 d_instantiate(dentry, new_inode); 583 inc_nlink(parent_inode); 584 fsnotify_mkdir(parent_inode, dentry); 585 586 out: 587 inode_unlock(parent_inode); 588 return dentry; 589 } 590 591 static int init_binder_logs(struct super_block *sb) 592 { 593 struct dentry *binder_logs_root_dir, *dentry, *proc_log_dir; 594 struct binderfs_info *info; 595 int ret = 0; 596 597 binder_logs_root_dir = binderfs_create_dir(sb->s_root, 598 "binder_logs"); 599 if (IS_ERR(binder_logs_root_dir)) { 600 ret = PTR_ERR(binder_logs_root_dir); 601 goto out; 602 } 603 604 dentry = binderfs_create_file(binder_logs_root_dir, "stats", 605 &binder_stats_fops, NULL); 606 if (IS_ERR(dentry)) { 607 ret = PTR_ERR(dentry); 608 goto out; 609 } 610 611 dentry = binderfs_create_file(binder_logs_root_dir, "state", 612 &binder_state_fops, NULL); 613 if (IS_ERR(dentry)) { 614 ret = PTR_ERR(dentry); 615 goto out; 616 } 617 618 dentry = binderfs_create_file(binder_logs_root_dir, "transactions", 619 &binder_transactions_fops, NULL); 620 if (IS_ERR(dentry)) { 621 ret = PTR_ERR(dentry); 622 goto out; 623 } 624 625 dentry = binderfs_create_file(binder_logs_root_dir, 626 "transaction_log", 627 &binder_transaction_log_fops, 628 &binder_transaction_log); 629 if (IS_ERR(dentry)) { 630 ret = PTR_ERR(dentry); 631 goto out; 632 } 633 634 dentry = binderfs_create_file(binder_logs_root_dir, 635 "failed_transaction_log", 636 &binder_transaction_log_fops, 637 &binder_transaction_log_failed); 638 if (IS_ERR(dentry)) { 639 ret = PTR_ERR(dentry); 640 goto out; 641 } 642 643 proc_log_dir = binderfs_create_dir(binder_logs_root_dir, "proc"); 644 if (IS_ERR(proc_log_dir)) { 645 ret = PTR_ERR(proc_log_dir); 646 goto out; 647 } 648 info = sb->s_fs_info; 649 info->proc_log_dir = proc_log_dir; 650 651 out: 652 return ret; 653 } 654 655 static int binderfs_fill_super(struct super_block *sb, void *data, int silent) 656 { 657 int ret; 658 struct binderfs_info *info; 659 struct inode *inode = NULL; 660 struct binderfs_device device_info = { 0 }; 661 const char *name; 662 size_t len; 663 664 sb->s_blocksize = PAGE_SIZE; 665 sb->s_blocksize_bits = PAGE_SHIFT; 666 667 /* 668 * The binderfs filesystem can be mounted by userns root in a 669 * non-initial userns. By default such mounts have the SB_I_NODEV flag 670 * set in s_iflags to prevent security issues where userns root can 671 * just create random device nodes via mknod() since it owns the 672 * filesystem mount. But binderfs does not allow to create any files 673 * including devices nodes. The only way to create binder devices nodes 674 * is through the binder-control device which userns root is explicitly 675 * allowed to do. So removing the SB_I_NODEV flag from s_iflags is both 676 * necessary and safe. 677 */ 678 sb->s_iflags &= ~SB_I_NODEV; 679 sb->s_iflags |= SB_I_NOEXEC; 680 sb->s_magic = BINDERFS_SUPER_MAGIC; 681 sb->s_op = &binderfs_super_ops; 682 sb->s_time_gran = 1; 683 684 sb->s_fs_info = kzalloc(sizeof(struct binderfs_info), GFP_KERNEL); 685 if (!sb->s_fs_info) 686 return -ENOMEM; 687 info = sb->s_fs_info; 688 689 info->ipc_ns = get_ipc_ns(current->nsproxy->ipc_ns); 690 691 ret = binderfs_parse_mount_opts(data, &info->mount_opts); 692 if (ret) 693 return ret; 694 695 info->root_gid = make_kgid(sb->s_user_ns, 0); 696 if (!gid_valid(info->root_gid)) 697 info->root_gid = GLOBAL_ROOT_GID; 698 info->root_uid = make_kuid(sb->s_user_ns, 0); 699 if (!uid_valid(info->root_uid)) 700 info->root_uid = GLOBAL_ROOT_UID; 701 702 inode = new_inode(sb); 703 if (!inode) 704 return -ENOMEM; 705 706 inode->i_ino = FIRST_INODE; 707 inode->i_fop = &simple_dir_operations; 708 inode->i_mode = S_IFDIR | 0755; 709 inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode); 710 inode->i_op = &binderfs_dir_inode_operations; 711 set_nlink(inode, 2); 712 713 sb->s_root = d_make_root(inode); 714 if (!sb->s_root) 715 return -ENOMEM; 716 717 ret = binderfs_binder_ctl_create(sb); 718 if (ret) 719 return ret; 720 721 name = binder_devices_param; 722 for (len = strcspn(name, ","); len > 0; len = strcspn(name, ",")) { 723 strscpy(device_info.name, name, len + 1); 724 ret = binderfs_binder_device_create(inode, NULL, &device_info); 725 if (ret) 726 return ret; 727 name += len; 728 if (*name == ',') 729 name++; 730 } 731 732 if (info->mount_opts.stats_mode == STATS_GLOBAL) 733 return init_binder_logs(sb); 734 735 return 0; 736 } 737 738 static struct dentry *binderfs_mount(struct file_system_type *fs_type, 739 int flags, const char *dev_name, 740 void *data) 741 { 742 return mount_nodev(fs_type, flags, data, binderfs_fill_super); 743 } 744 745 static void binderfs_kill_super(struct super_block *sb) 746 { 747 struct binderfs_info *info = sb->s_fs_info; 748 749 kill_litter_super(sb); 750 751 if (info && info->ipc_ns) 752 put_ipc_ns(info->ipc_ns); 753 754 kfree(info); 755 } 756 757 static struct file_system_type binder_fs_type = { 758 .name = "binder", 759 .mount = binderfs_mount, 760 .kill_sb = binderfs_kill_super, 761 .fs_flags = FS_USERNS_MOUNT, 762 }; 763 764 int __init init_binderfs(void) 765 { 766 int ret; 767 const char *name; 768 size_t len; 769 770 /* Verify that the default binderfs device names are valid. */ 771 name = binder_devices_param; 772 for (len = strcspn(name, ","); len > 0; len = strcspn(name, ",")) { 773 if (len > BINDERFS_MAX_NAME) 774 return -E2BIG; 775 name += len; 776 if (*name == ',') 777 name++; 778 } 779 780 /* Allocate new major number for binderfs. */ 781 ret = alloc_chrdev_region(&binderfs_dev, 0, BINDERFS_MAX_MINOR, 782 "binder"); 783 if (ret) 784 return ret; 785 786 ret = register_filesystem(&binder_fs_type); 787 if (ret) { 788 unregister_chrdev_region(binderfs_dev, BINDERFS_MAX_MINOR); 789 return ret; 790 } 791 792 return ret; 793 } 794