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/fs_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 binderfs_param { 52 Opt_max, 53 Opt_stats_mode, 54 }; 55 56 enum binderfs_stats_mode { 57 binderfs_stats_mode_unset, 58 binderfs_stats_mode_global, 59 }; 60 61 static const struct constant_table binderfs_param_stats[] = { 62 { "global", binderfs_stats_mode_global }, 63 {} 64 }; 65 66 const struct fs_parameter_spec binderfs_fs_parameters[] = { 67 fsparam_u32("max", Opt_max), 68 fsparam_enum("stats", Opt_stats_mode, binderfs_param_stats), 69 {} 70 }; 71 72 static inline struct binderfs_info *BINDERFS_SB(const struct super_block *sb) 73 { 74 return sb->s_fs_info; 75 } 76 77 bool is_binderfs_device(const struct inode *inode) 78 { 79 if (inode->i_sb->s_magic == BINDERFS_SUPER_MAGIC) 80 return true; 81 82 return false; 83 } 84 85 /** 86 * binderfs_binder_device_create - allocate inode from super block of a 87 * binderfs mount 88 * @ref_inode: inode from wich the super block will be taken 89 * @userp: buffer to copy information about new device for userspace to 90 * @req: struct binderfs_device as copied from userspace 91 * 92 * This function allocates a new binder_device and reserves a new minor 93 * number for it. 94 * Minor numbers are limited and tracked globally in binderfs_minors. The 95 * function will stash a struct binder_device for the specific binder 96 * device in i_private of the inode. 97 * It will go on to allocate a new inode from the super block of the 98 * filesystem mount, stash a struct binder_device in its i_private field 99 * and attach a dentry to that inode. 100 * 101 * Return: 0 on success, negative errno on failure 102 */ 103 static int binderfs_binder_device_create(struct inode *ref_inode, 104 struct binderfs_device __user *userp, 105 struct binderfs_device *req) 106 { 107 int minor, ret; 108 struct dentry *dentry, *root; 109 struct binder_device *device; 110 char *name = NULL; 111 size_t name_len; 112 struct inode *inode = NULL; 113 struct super_block *sb = ref_inode->i_sb; 114 struct binderfs_info *info = sb->s_fs_info; 115 #if defined(CONFIG_IPC_NS) 116 bool use_reserve = (info->ipc_ns == &init_ipc_ns); 117 #else 118 bool use_reserve = true; 119 #endif 120 121 /* Reserve new minor number for the new device. */ 122 mutex_lock(&binderfs_minors_mutex); 123 if (++info->device_count <= info->mount_opts.max) 124 minor = ida_alloc_max(&binderfs_minors, 125 use_reserve ? BINDERFS_MAX_MINOR : 126 BINDERFS_MAX_MINOR_CAPPED, 127 GFP_KERNEL); 128 else 129 minor = -ENOSPC; 130 if (minor < 0) { 131 --info->device_count; 132 mutex_unlock(&binderfs_minors_mutex); 133 return minor; 134 } 135 mutex_unlock(&binderfs_minors_mutex); 136 137 ret = -ENOMEM; 138 device = kzalloc(sizeof(*device), GFP_KERNEL); 139 if (!device) 140 goto err; 141 142 inode = new_inode(sb); 143 if (!inode) 144 goto err; 145 146 inode->i_ino = minor + INODE_OFFSET; 147 inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode); 148 init_special_inode(inode, S_IFCHR | 0600, 149 MKDEV(MAJOR(binderfs_dev), minor)); 150 inode->i_fop = &binder_fops; 151 inode->i_uid = info->root_uid; 152 inode->i_gid = info->root_gid; 153 154 req->name[BINDERFS_MAX_NAME] = '\0'; /* NUL-terminate */ 155 name_len = strlen(req->name); 156 /* Make sure to include terminating NUL byte */ 157 name = kmemdup(req->name, name_len + 1, GFP_KERNEL); 158 if (!name) 159 goto err; 160 161 refcount_set(&device->ref, 1); 162 device->binderfs_inode = inode; 163 device->context.binder_context_mgr_uid = INVALID_UID; 164 device->context.name = name; 165 device->miscdev.name = name; 166 device->miscdev.minor = minor; 167 mutex_init(&device->context.context_mgr_node_lock); 168 169 req->major = MAJOR(binderfs_dev); 170 req->minor = minor; 171 172 if (userp && copy_to_user(userp, req, sizeof(*req))) { 173 ret = -EFAULT; 174 goto err; 175 } 176 177 root = sb->s_root; 178 inode_lock(d_inode(root)); 179 180 /* look it up */ 181 dentry = lookup_one_len(name, root, name_len); 182 if (IS_ERR(dentry)) { 183 inode_unlock(d_inode(root)); 184 ret = PTR_ERR(dentry); 185 goto err; 186 } 187 188 if (d_really_is_positive(dentry)) { 189 /* already exists */ 190 dput(dentry); 191 inode_unlock(d_inode(root)); 192 ret = -EEXIST; 193 goto err; 194 } 195 196 inode->i_private = device; 197 d_instantiate(dentry, inode); 198 fsnotify_create(root->d_inode, dentry); 199 inode_unlock(d_inode(root)); 200 201 return 0; 202 203 err: 204 kfree(name); 205 kfree(device); 206 mutex_lock(&binderfs_minors_mutex); 207 --info->device_count; 208 ida_free(&binderfs_minors, minor); 209 mutex_unlock(&binderfs_minors_mutex); 210 iput(inode); 211 212 return ret; 213 } 214 215 /** 216 * binderfs_ctl_ioctl - handle binder device node allocation requests 217 * 218 * The request handler for the binder-control device. All requests operate on 219 * the binderfs mount the binder-control device resides in: 220 * - BINDER_CTL_ADD 221 * Allocate a new binder device. 222 * 223 * Return: 0 on success, negative errno on failure 224 */ 225 static long binder_ctl_ioctl(struct file *file, unsigned int cmd, 226 unsigned long arg) 227 { 228 int ret = -EINVAL; 229 struct inode *inode = file_inode(file); 230 struct binderfs_device __user *device = (struct binderfs_device __user *)arg; 231 struct binderfs_device device_req; 232 233 switch (cmd) { 234 case BINDER_CTL_ADD: 235 ret = copy_from_user(&device_req, device, sizeof(device_req)); 236 if (ret) { 237 ret = -EFAULT; 238 break; 239 } 240 241 ret = binderfs_binder_device_create(inode, device, &device_req); 242 break; 243 default: 244 break; 245 } 246 247 return ret; 248 } 249 250 static void binderfs_evict_inode(struct inode *inode) 251 { 252 struct binder_device *device = inode->i_private; 253 struct binderfs_info *info = BINDERFS_SB(inode->i_sb); 254 255 clear_inode(inode); 256 257 if (!S_ISCHR(inode->i_mode) || !device) 258 return; 259 260 mutex_lock(&binderfs_minors_mutex); 261 --info->device_count; 262 ida_free(&binderfs_minors, device->miscdev.minor); 263 mutex_unlock(&binderfs_minors_mutex); 264 265 if (refcount_dec_and_test(&device->ref)) { 266 kfree(device->context.name); 267 kfree(device); 268 } 269 } 270 271 static int binderfs_fs_context_parse_param(struct fs_context *fc, 272 struct fs_parameter *param) 273 { 274 int opt; 275 struct binderfs_mount_opts *ctx = fc->fs_private; 276 struct fs_parse_result result; 277 278 opt = fs_parse(fc, binderfs_fs_parameters, param, &result); 279 if (opt < 0) 280 return opt; 281 282 switch (opt) { 283 case Opt_max: 284 if (result.uint_32 > BINDERFS_MAX_MINOR) 285 return invalfc(fc, "Bad value for '%s'", param->key); 286 287 ctx->max = result.uint_32; 288 break; 289 case Opt_stats_mode: 290 if (!capable(CAP_SYS_ADMIN)) 291 return -EPERM; 292 293 ctx->stats_mode = result.uint_32; 294 break; 295 default: 296 return invalfc(fc, "Unsupported parameter '%s'", param->key); 297 } 298 299 return 0; 300 } 301 302 static int binderfs_fs_context_reconfigure(struct fs_context *fc) 303 { 304 struct binderfs_mount_opts *ctx = fc->fs_private; 305 struct binderfs_info *info = BINDERFS_SB(fc->root->d_sb); 306 307 if (info->mount_opts.stats_mode != ctx->stats_mode) 308 return invalfc(fc, "Binderfs stats mode cannot be changed during a remount"); 309 310 info->mount_opts.stats_mode = ctx->stats_mode; 311 info->mount_opts.max = ctx->max; 312 return 0; 313 } 314 315 static int binderfs_show_options(struct seq_file *seq, struct dentry *root) 316 { 317 struct binderfs_info *info = BINDERFS_SB(root->d_sb); 318 319 if (info->mount_opts.max <= BINDERFS_MAX_MINOR) 320 seq_printf(seq, ",max=%d", info->mount_opts.max); 321 322 switch (info->mount_opts.stats_mode) { 323 case binderfs_stats_mode_unset: 324 break; 325 case binderfs_stats_mode_global: 326 seq_printf(seq, ",stats=global"); 327 break; 328 } 329 330 return 0; 331 } 332 333 static void binderfs_put_super(struct super_block *sb) 334 { 335 struct binderfs_info *info = sb->s_fs_info; 336 337 if (info && info->ipc_ns) 338 put_ipc_ns(info->ipc_ns); 339 340 kfree(info); 341 sb->s_fs_info = NULL; 342 } 343 344 static const struct super_operations binderfs_super_ops = { 345 .evict_inode = binderfs_evict_inode, 346 .show_options = binderfs_show_options, 347 .statfs = simple_statfs, 348 .put_super = binderfs_put_super, 349 }; 350 351 static inline bool is_binderfs_control_device(const struct dentry *dentry) 352 { 353 struct binderfs_info *info = dentry->d_sb->s_fs_info; 354 return info->control_dentry == dentry; 355 } 356 357 static int binderfs_rename(struct inode *old_dir, struct dentry *old_dentry, 358 struct inode *new_dir, struct dentry *new_dentry, 359 unsigned int flags) 360 { 361 if (is_binderfs_control_device(old_dentry) || 362 is_binderfs_control_device(new_dentry)) 363 return -EPERM; 364 365 return simple_rename(old_dir, old_dentry, new_dir, new_dentry, flags); 366 } 367 368 static int binderfs_unlink(struct inode *dir, struct dentry *dentry) 369 { 370 if (is_binderfs_control_device(dentry)) 371 return -EPERM; 372 373 return simple_unlink(dir, dentry); 374 } 375 376 static const struct file_operations binder_ctl_fops = { 377 .owner = THIS_MODULE, 378 .open = nonseekable_open, 379 .unlocked_ioctl = binder_ctl_ioctl, 380 .compat_ioctl = binder_ctl_ioctl, 381 .llseek = noop_llseek, 382 }; 383 384 /** 385 * binderfs_binder_ctl_create - create a new binder-control device 386 * @sb: super block of the binderfs mount 387 * 388 * This function creates a new binder-control device node in the binderfs mount 389 * referred to by @sb. 390 * 391 * Return: 0 on success, negative errno on failure 392 */ 393 static int binderfs_binder_ctl_create(struct super_block *sb) 394 { 395 int minor, ret; 396 struct dentry *dentry; 397 struct binder_device *device; 398 struct inode *inode = NULL; 399 struct dentry *root = sb->s_root; 400 struct binderfs_info *info = sb->s_fs_info; 401 #if defined(CONFIG_IPC_NS) 402 bool use_reserve = (info->ipc_ns == &init_ipc_ns); 403 #else 404 bool use_reserve = true; 405 #endif 406 407 device = kzalloc(sizeof(*device), GFP_KERNEL); 408 if (!device) 409 return -ENOMEM; 410 411 /* If we have already created a binder-control node, return. */ 412 if (info->control_dentry) { 413 ret = 0; 414 goto out; 415 } 416 417 ret = -ENOMEM; 418 inode = new_inode(sb); 419 if (!inode) 420 goto out; 421 422 /* Reserve a new minor number for the new device. */ 423 mutex_lock(&binderfs_minors_mutex); 424 minor = ida_alloc_max(&binderfs_minors, 425 use_reserve ? BINDERFS_MAX_MINOR : 426 BINDERFS_MAX_MINOR_CAPPED, 427 GFP_KERNEL); 428 mutex_unlock(&binderfs_minors_mutex); 429 if (minor < 0) { 430 ret = minor; 431 goto out; 432 } 433 434 inode->i_ino = SECOND_INODE; 435 inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode); 436 init_special_inode(inode, S_IFCHR | 0600, 437 MKDEV(MAJOR(binderfs_dev), minor)); 438 inode->i_fop = &binder_ctl_fops; 439 inode->i_uid = info->root_uid; 440 inode->i_gid = info->root_gid; 441 442 device->binderfs_inode = inode; 443 device->miscdev.minor = minor; 444 445 dentry = d_alloc_name(root, "binder-control"); 446 if (!dentry) 447 goto out; 448 449 inode->i_private = device; 450 info->control_dentry = dentry; 451 d_add(dentry, inode); 452 453 return 0; 454 455 out: 456 kfree(device); 457 iput(inode); 458 459 return ret; 460 } 461 462 static const struct inode_operations binderfs_dir_inode_operations = { 463 .lookup = simple_lookup, 464 .rename = binderfs_rename, 465 .unlink = binderfs_unlink, 466 }; 467 468 static struct inode *binderfs_make_inode(struct super_block *sb, int mode) 469 { 470 struct inode *ret; 471 472 ret = new_inode(sb); 473 if (ret) { 474 ret->i_ino = iunique(sb, BINDERFS_MAX_MINOR + INODE_OFFSET); 475 ret->i_mode = mode; 476 ret->i_atime = ret->i_mtime = ret->i_ctime = current_time(ret); 477 } 478 return ret; 479 } 480 481 static struct dentry *binderfs_create_dentry(struct dentry *parent, 482 const char *name) 483 { 484 struct dentry *dentry; 485 486 dentry = lookup_one_len(name, parent, strlen(name)); 487 if (IS_ERR(dentry)) 488 return dentry; 489 490 /* Return error if the file/dir already exists. */ 491 if (d_really_is_positive(dentry)) { 492 dput(dentry); 493 return ERR_PTR(-EEXIST); 494 } 495 496 return dentry; 497 } 498 499 void binderfs_remove_file(struct dentry *dentry) 500 { 501 struct inode *parent_inode; 502 503 parent_inode = d_inode(dentry->d_parent); 504 inode_lock(parent_inode); 505 if (simple_positive(dentry)) { 506 dget(dentry); 507 simple_unlink(parent_inode, dentry); 508 d_delete(dentry); 509 dput(dentry); 510 } 511 inode_unlock(parent_inode); 512 } 513 514 struct dentry *binderfs_create_file(struct dentry *parent, const char *name, 515 const struct file_operations *fops, 516 void *data) 517 { 518 struct dentry *dentry; 519 struct inode *new_inode, *parent_inode; 520 struct super_block *sb; 521 522 parent_inode = d_inode(parent); 523 inode_lock(parent_inode); 524 525 dentry = binderfs_create_dentry(parent, name); 526 if (IS_ERR(dentry)) 527 goto out; 528 529 sb = parent_inode->i_sb; 530 new_inode = binderfs_make_inode(sb, S_IFREG | 0444); 531 if (!new_inode) { 532 dput(dentry); 533 dentry = ERR_PTR(-ENOMEM); 534 goto out; 535 } 536 537 new_inode->i_fop = fops; 538 new_inode->i_private = data; 539 d_instantiate(dentry, new_inode); 540 fsnotify_create(parent_inode, dentry); 541 542 out: 543 inode_unlock(parent_inode); 544 return dentry; 545 } 546 547 static struct dentry *binderfs_create_dir(struct dentry *parent, 548 const char *name) 549 { 550 struct dentry *dentry; 551 struct inode *new_inode, *parent_inode; 552 struct super_block *sb; 553 554 parent_inode = d_inode(parent); 555 inode_lock(parent_inode); 556 557 dentry = binderfs_create_dentry(parent, name); 558 if (IS_ERR(dentry)) 559 goto out; 560 561 sb = parent_inode->i_sb; 562 new_inode = binderfs_make_inode(sb, S_IFDIR | 0755); 563 if (!new_inode) { 564 dput(dentry); 565 dentry = ERR_PTR(-ENOMEM); 566 goto out; 567 } 568 569 new_inode->i_fop = &simple_dir_operations; 570 new_inode->i_op = &simple_dir_inode_operations; 571 572 set_nlink(new_inode, 2); 573 d_instantiate(dentry, new_inode); 574 inc_nlink(parent_inode); 575 fsnotify_mkdir(parent_inode, dentry); 576 577 out: 578 inode_unlock(parent_inode); 579 return dentry; 580 } 581 582 static int init_binder_logs(struct super_block *sb) 583 { 584 struct dentry *binder_logs_root_dir, *dentry, *proc_log_dir; 585 struct binderfs_info *info; 586 int ret = 0; 587 588 binder_logs_root_dir = binderfs_create_dir(sb->s_root, 589 "binder_logs"); 590 if (IS_ERR(binder_logs_root_dir)) { 591 ret = PTR_ERR(binder_logs_root_dir); 592 goto out; 593 } 594 595 dentry = binderfs_create_file(binder_logs_root_dir, "stats", 596 &binder_stats_fops, NULL); 597 if (IS_ERR(dentry)) { 598 ret = PTR_ERR(dentry); 599 goto out; 600 } 601 602 dentry = binderfs_create_file(binder_logs_root_dir, "state", 603 &binder_state_fops, NULL); 604 if (IS_ERR(dentry)) { 605 ret = PTR_ERR(dentry); 606 goto out; 607 } 608 609 dentry = binderfs_create_file(binder_logs_root_dir, "transactions", 610 &binder_transactions_fops, NULL); 611 if (IS_ERR(dentry)) { 612 ret = PTR_ERR(dentry); 613 goto out; 614 } 615 616 dentry = binderfs_create_file(binder_logs_root_dir, 617 "transaction_log", 618 &binder_transaction_log_fops, 619 &binder_transaction_log); 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 "failed_transaction_log", 627 &binder_transaction_log_fops, 628 &binder_transaction_log_failed); 629 if (IS_ERR(dentry)) { 630 ret = PTR_ERR(dentry); 631 goto out; 632 } 633 634 proc_log_dir = binderfs_create_dir(binder_logs_root_dir, "proc"); 635 if (IS_ERR(proc_log_dir)) { 636 ret = PTR_ERR(proc_log_dir); 637 goto out; 638 } 639 info = sb->s_fs_info; 640 info->proc_log_dir = proc_log_dir; 641 642 out: 643 return ret; 644 } 645 646 static int binderfs_fill_super(struct super_block *sb, struct fs_context *fc) 647 { 648 int ret; 649 struct binderfs_info *info; 650 struct binderfs_mount_opts *ctx = fc->fs_private; 651 struct inode *inode = NULL; 652 struct binderfs_device device_info = { 0 }; 653 const char *name; 654 size_t len; 655 656 sb->s_blocksize = PAGE_SIZE; 657 sb->s_blocksize_bits = PAGE_SHIFT; 658 659 /* 660 * The binderfs filesystem can be mounted by userns root in a 661 * non-initial userns. By default such mounts have the SB_I_NODEV flag 662 * set in s_iflags to prevent security issues where userns root can 663 * just create random device nodes via mknod() since it owns the 664 * filesystem mount. But binderfs does not allow to create any files 665 * including devices nodes. The only way to create binder devices nodes 666 * is through the binder-control device which userns root is explicitly 667 * allowed to do. So removing the SB_I_NODEV flag from s_iflags is both 668 * necessary and safe. 669 */ 670 sb->s_iflags &= ~SB_I_NODEV; 671 sb->s_iflags |= SB_I_NOEXEC; 672 sb->s_magic = BINDERFS_SUPER_MAGIC; 673 sb->s_op = &binderfs_super_ops; 674 sb->s_time_gran = 1; 675 676 sb->s_fs_info = kzalloc(sizeof(struct binderfs_info), GFP_KERNEL); 677 if (!sb->s_fs_info) 678 return -ENOMEM; 679 info = sb->s_fs_info; 680 681 info->ipc_ns = get_ipc_ns(current->nsproxy->ipc_ns); 682 683 info->root_gid = make_kgid(sb->s_user_ns, 0); 684 if (!gid_valid(info->root_gid)) 685 info->root_gid = GLOBAL_ROOT_GID; 686 info->root_uid = make_kuid(sb->s_user_ns, 0); 687 if (!uid_valid(info->root_uid)) 688 info->root_uid = GLOBAL_ROOT_UID; 689 info->mount_opts.max = ctx->max; 690 info->mount_opts.stats_mode = ctx->stats_mode; 691 692 inode = new_inode(sb); 693 if (!inode) 694 return -ENOMEM; 695 696 inode->i_ino = FIRST_INODE; 697 inode->i_fop = &simple_dir_operations; 698 inode->i_mode = S_IFDIR | 0755; 699 inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode); 700 inode->i_op = &binderfs_dir_inode_operations; 701 set_nlink(inode, 2); 702 703 sb->s_root = d_make_root(inode); 704 if (!sb->s_root) 705 return -ENOMEM; 706 707 ret = binderfs_binder_ctl_create(sb); 708 if (ret) 709 return ret; 710 711 name = binder_devices_param; 712 for (len = strcspn(name, ","); len > 0; len = strcspn(name, ",")) { 713 strscpy(device_info.name, name, len + 1); 714 ret = binderfs_binder_device_create(inode, NULL, &device_info); 715 if (ret) 716 return ret; 717 name += len; 718 if (*name == ',') 719 name++; 720 } 721 722 if (info->mount_opts.stats_mode == binderfs_stats_mode_global) 723 return init_binder_logs(sb); 724 725 return 0; 726 } 727 728 static int binderfs_fs_context_get_tree(struct fs_context *fc) 729 { 730 return get_tree_nodev(fc, binderfs_fill_super); 731 } 732 733 static void binderfs_fs_context_free(struct fs_context *fc) 734 { 735 struct binderfs_mount_opts *ctx = fc->fs_private; 736 737 kfree(ctx); 738 } 739 740 static const struct fs_context_operations binderfs_fs_context_ops = { 741 .free = binderfs_fs_context_free, 742 .get_tree = binderfs_fs_context_get_tree, 743 .parse_param = binderfs_fs_context_parse_param, 744 .reconfigure = binderfs_fs_context_reconfigure, 745 }; 746 747 static int binderfs_init_fs_context(struct fs_context *fc) 748 { 749 struct binderfs_mount_opts *ctx = fc->fs_private; 750 751 ctx = kzalloc(sizeof(struct binderfs_mount_opts), GFP_KERNEL); 752 if (!ctx) 753 return -ENOMEM; 754 755 ctx->max = BINDERFS_MAX_MINOR; 756 ctx->stats_mode = binderfs_stats_mode_unset; 757 758 fc->fs_private = ctx; 759 fc->ops = &binderfs_fs_context_ops; 760 761 return 0; 762 } 763 764 static struct file_system_type binder_fs_type = { 765 .name = "binder", 766 .init_fs_context = binderfs_init_fs_context, 767 .parameters = binderfs_fs_parameters, 768 .kill_sb = kill_litter_super, 769 .fs_flags = FS_USERNS_MOUNT, 770 }; 771 772 int __init init_binderfs(void) 773 { 774 int ret; 775 const char *name; 776 size_t len; 777 778 /* Verify that the default binderfs device names are valid. */ 779 name = binder_devices_param; 780 for (len = strcspn(name, ","); len > 0; len = strcspn(name, ",")) { 781 if (len > BINDERFS_MAX_NAME) 782 return -E2BIG; 783 name += len; 784 if (*name == ',') 785 name++; 786 } 787 788 /* Allocate new major number for binderfs. */ 789 ret = alloc_chrdev_region(&binderfs_dev, 0, BINDERFS_MAX_MINOR, 790 "binder"); 791 if (ret) 792 return ret; 793 794 ret = register_filesystem(&binder_fs_type); 795 if (ret) { 796 unregister_chrdev_region(binderfs_dev, BINDERFS_MAX_MINOR); 797 return ret; 798 } 799 800 return ret; 801 } 802