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 47static dev_t binderfs_dev; 48static DEFINE_MUTEX(binderfs_minors_mutex); 49static DEFINE_IDA(binderfs_minors); 50 51enum binderfs_param { 52 Opt_max, 53 Opt_stats_mode, 54}; 55 56enum binderfs_stats_mode { 57 binderfs_stats_mode_unset, 58 binderfs_stats_mode_global, 59}; 60 61static const struct constant_table binderfs_param_stats[] = { 62 { "global", binderfs_stats_mode_global }, 63 {} 64}; 65 66static 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 72static inline struct binderfs_info *BINDERFS_SB(const struct super_block *sb) 73{ 74 return sb->s_fs_info; 75} 76 77bool 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 */ 103static 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 203err: 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 */ 225static 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 250static 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 271static 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 302static 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 315static 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 333static const struct super_operations binderfs_super_ops = { 334 .evict_inode = binderfs_evict_inode, 335 .show_options = binderfs_show_options, 336 .statfs = simple_statfs, 337}; 338 339static inline bool is_binderfs_control_device(const struct dentry *dentry) 340{ 341 struct binderfs_info *info = dentry->d_sb->s_fs_info; 342 343 return info->control_dentry == dentry; 344} 345 346static int binderfs_rename(struct inode *old_dir, struct dentry *old_dentry, 347 struct inode *new_dir, struct dentry *new_dentry, 348 unsigned int flags) 349{ 350 if (is_binderfs_control_device(old_dentry) || 351 is_binderfs_control_device(new_dentry)) 352 return -EPERM; 353 354 return simple_rename(old_dir, old_dentry, new_dir, new_dentry, flags); 355} 356 357static int binderfs_unlink(struct inode *dir, struct dentry *dentry) 358{ 359 if (is_binderfs_control_device(dentry)) 360 return -EPERM; 361 362 return simple_unlink(dir, dentry); 363} 364 365static const struct file_operations binder_ctl_fops = { 366 .owner = THIS_MODULE, 367 .open = nonseekable_open, 368 .unlocked_ioctl = binder_ctl_ioctl, 369 .compat_ioctl = binder_ctl_ioctl, 370 .llseek = noop_llseek, 371}; 372 373/** 374 * binderfs_binder_ctl_create - create a new binder-control device 375 * @sb: super block of the binderfs mount 376 * 377 * This function creates a new binder-control device node in the binderfs mount 378 * referred to by @sb. 379 * 380 * Return: 0 on success, negative errno on failure 381 */ 382static int binderfs_binder_ctl_create(struct super_block *sb) 383{ 384 int minor, ret; 385 struct dentry *dentry; 386 struct binder_device *device; 387 struct inode *inode = NULL; 388 struct dentry *root = sb->s_root; 389 struct binderfs_info *info = sb->s_fs_info; 390#if defined(CONFIG_IPC_NS) 391 bool use_reserve = (info->ipc_ns == &init_ipc_ns); 392#else 393 bool use_reserve = true; 394#endif 395 396 device = kzalloc(sizeof(*device), GFP_KERNEL); 397 if (!device) 398 return -ENOMEM; 399 400 /* If we have already created a binder-control node, return. */ 401 if (info->control_dentry) { 402 ret = 0; 403 goto out; 404 } 405 406 ret = -ENOMEM; 407 inode = new_inode(sb); 408 if (!inode) 409 goto out; 410 411 /* Reserve a new minor number for the new device. */ 412 mutex_lock(&binderfs_minors_mutex); 413 minor = ida_alloc_max(&binderfs_minors, 414 use_reserve ? BINDERFS_MAX_MINOR : 415 BINDERFS_MAX_MINOR_CAPPED, 416 GFP_KERNEL); 417 mutex_unlock(&binderfs_minors_mutex); 418 if (minor < 0) { 419 ret = minor; 420 goto out; 421 } 422 423 inode->i_ino = SECOND_INODE; 424 inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode); 425 init_special_inode(inode, S_IFCHR | 0600, 426 MKDEV(MAJOR(binderfs_dev), minor)); 427 inode->i_fop = &binder_ctl_fops; 428 inode->i_uid = info->root_uid; 429 inode->i_gid = info->root_gid; 430 431 refcount_set(&device->ref, 1); 432 device->binderfs_inode = inode; 433 device->miscdev.minor = minor; 434 435 dentry = d_alloc_name(root, "binder-control"); 436 if (!dentry) 437 goto out; 438 439 inode->i_private = device; 440 info->control_dentry = dentry; 441 d_add(dentry, inode); 442 443 return 0; 444 445out: 446 kfree(device); 447 iput(inode); 448 449 return ret; 450} 451 452static const struct inode_operations binderfs_dir_inode_operations = { 453 .lookup = simple_lookup, 454 .rename = binderfs_rename, 455 .unlink = binderfs_unlink, 456}; 457 458static struct inode *binderfs_make_inode(struct super_block *sb, int mode) 459{ 460 struct inode *ret; 461 462 ret = new_inode(sb); 463 if (ret) { 464 ret->i_ino = iunique(sb, BINDERFS_MAX_MINOR + INODE_OFFSET); 465 ret->i_mode = mode; 466 ret->i_atime = ret->i_mtime = ret->i_ctime = current_time(ret); 467 } 468 return ret; 469} 470 471static struct dentry *binderfs_create_dentry(struct dentry *parent, 472 const char *name) 473{ 474 struct dentry *dentry; 475 476 dentry = lookup_one_len(name, parent, strlen(name)); 477 if (IS_ERR(dentry)) 478 return dentry; 479 480 /* Return error if the file/dir already exists. */ 481 if (d_really_is_positive(dentry)) { 482 dput(dentry); 483 return ERR_PTR(-EEXIST); 484 } 485 486 return dentry; 487} 488 489void binderfs_remove_file(struct dentry *dentry) 490{ 491 struct inode *parent_inode; 492 493 parent_inode = d_inode(dentry->d_parent); 494 inode_lock(parent_inode); 495 if (simple_positive(dentry)) { 496 dget(dentry); 497 simple_unlink(parent_inode, dentry); 498 d_delete(dentry); 499 dput(dentry); 500 } 501 inode_unlock(parent_inode); 502} 503 504struct dentry *binderfs_create_file(struct dentry *parent, const char *name, 505 const struct file_operations *fops, 506 void *data) 507{ 508 struct dentry *dentry; 509 struct inode *new_inode, *parent_inode; 510 struct super_block *sb; 511 512 parent_inode = d_inode(parent); 513 inode_lock(parent_inode); 514 515 dentry = binderfs_create_dentry(parent, name); 516 if (IS_ERR(dentry)) 517 goto out; 518 519 sb = parent_inode->i_sb; 520 new_inode = binderfs_make_inode(sb, S_IFREG | 0444); 521 if (!new_inode) { 522 dput(dentry); 523 dentry = ERR_PTR(-ENOMEM); 524 goto out; 525 } 526 527 new_inode->i_fop = fops; 528 new_inode->i_private = data; 529 d_instantiate(dentry, new_inode); 530 fsnotify_create(parent_inode, dentry); 531 532out: 533 inode_unlock(parent_inode); 534 return dentry; 535} 536 537static struct dentry *binderfs_create_dir(struct dentry *parent, 538 const char *name) 539{ 540 struct dentry *dentry; 541 struct inode *new_inode, *parent_inode; 542 struct super_block *sb; 543 544 parent_inode = d_inode(parent); 545 inode_lock(parent_inode); 546 547 dentry = binderfs_create_dentry(parent, name); 548 if (IS_ERR(dentry)) 549 goto out; 550 551 sb = parent_inode->i_sb; 552 new_inode = binderfs_make_inode(sb, S_IFDIR | 0755); 553 if (!new_inode) { 554 dput(dentry); 555 dentry = ERR_PTR(-ENOMEM); 556 goto out; 557 } 558 559 new_inode->i_fop = &simple_dir_operations; 560 new_inode->i_op = &simple_dir_inode_operations; 561 562 set_nlink(new_inode, 2); 563 d_instantiate(dentry, new_inode); 564 inc_nlink(parent_inode); 565 fsnotify_mkdir(parent_inode, dentry); 566 567out: 568 inode_unlock(parent_inode); 569 return dentry; 570} 571 572static int init_binder_logs(struct super_block *sb) 573{ 574 struct dentry *binder_logs_root_dir, *dentry, *proc_log_dir; 575 struct binderfs_info *info; 576 int ret = 0; 577 578 binder_logs_root_dir = binderfs_create_dir(sb->s_root, 579 "binder_logs"); 580 if (IS_ERR(binder_logs_root_dir)) { 581 ret = PTR_ERR(binder_logs_root_dir); 582 goto out; 583 } 584 585 dentry = binderfs_create_file(binder_logs_root_dir, "stats", 586 &binder_stats_fops, NULL); 587 if (IS_ERR(dentry)) { 588 ret = PTR_ERR(dentry); 589 goto out; 590 } 591 592 dentry = binderfs_create_file(binder_logs_root_dir, "state", 593 &binder_state_fops, NULL); 594 if (IS_ERR(dentry)) { 595 ret = PTR_ERR(dentry); 596 goto out; 597 } 598 599 dentry = binderfs_create_file(binder_logs_root_dir, "transactions", 600 &binder_transactions_fops, NULL); 601 if (IS_ERR(dentry)) { 602 ret = PTR_ERR(dentry); 603 goto out; 604 } 605 606 dentry = binderfs_create_file(binder_logs_root_dir, 607 "transaction_log", 608 &binder_transaction_log_fops, 609 &binder_transaction_log); 610 if (IS_ERR(dentry)) { 611 ret = PTR_ERR(dentry); 612 goto out; 613 } 614 615 dentry = binderfs_create_file(binder_logs_root_dir, 616 "failed_transaction_log", 617 &binder_transaction_log_fops, 618 &binder_transaction_log_failed); 619 if (IS_ERR(dentry)) { 620 ret = PTR_ERR(dentry); 621 goto out; 622 } 623 624 proc_log_dir = binderfs_create_dir(binder_logs_root_dir, "proc"); 625 if (IS_ERR(proc_log_dir)) { 626 ret = PTR_ERR(proc_log_dir); 627 goto out; 628 } 629 info = sb->s_fs_info; 630 info->proc_log_dir = proc_log_dir; 631 632out: 633 return ret; 634} 635 636static int binderfs_fill_super(struct super_block *sb, struct fs_context *fc) 637{ 638 int ret; 639 struct binderfs_info *info; 640 struct binderfs_mount_opts *ctx = fc->fs_private; 641 struct inode *inode = NULL; 642 struct binderfs_device device_info = {}; 643 const char *name; 644 size_t len; 645 646 sb->s_blocksize = PAGE_SIZE; 647 sb->s_blocksize_bits = PAGE_SHIFT; 648 649 /* 650 * The binderfs filesystem can be mounted by userns root in a 651 * non-initial userns. By default such mounts have the SB_I_NODEV flag 652 * set in s_iflags to prevent security issues where userns root can 653 * just create random device nodes via mknod() since it owns the 654 * filesystem mount. But binderfs does not allow to create any files 655 * including devices nodes. The only way to create binder devices nodes 656 * is through the binder-control device which userns root is explicitly 657 * allowed to do. So removing the SB_I_NODEV flag from s_iflags is both 658 * necessary and safe. 659 */ 660 sb->s_iflags &= ~SB_I_NODEV; 661 sb->s_iflags |= SB_I_NOEXEC; 662 sb->s_magic = BINDERFS_SUPER_MAGIC; 663 sb->s_op = &binderfs_super_ops; 664 sb->s_time_gran = 1; 665 666 sb->s_fs_info = kzalloc(sizeof(struct binderfs_info), GFP_KERNEL); 667 if (!sb->s_fs_info) 668 return -ENOMEM; 669 info = sb->s_fs_info; 670 671 info->ipc_ns = get_ipc_ns(current->nsproxy->ipc_ns); 672 673 info->root_gid = make_kgid(sb->s_user_ns, 0); 674 if (!gid_valid(info->root_gid)) 675 info->root_gid = GLOBAL_ROOT_GID; 676 info->root_uid = make_kuid(sb->s_user_ns, 0); 677 if (!uid_valid(info->root_uid)) 678 info->root_uid = GLOBAL_ROOT_UID; 679 info->mount_opts.max = ctx->max; 680 info->mount_opts.stats_mode = ctx->stats_mode; 681 682 inode = new_inode(sb); 683 if (!inode) 684 return -ENOMEM; 685 686 inode->i_ino = FIRST_INODE; 687 inode->i_fop = &simple_dir_operations; 688 inode->i_mode = S_IFDIR | 0755; 689 inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode); 690 inode->i_op = &binderfs_dir_inode_operations; 691 set_nlink(inode, 2); 692 693 sb->s_root = d_make_root(inode); 694 if (!sb->s_root) 695 return -ENOMEM; 696 697 ret = binderfs_binder_ctl_create(sb); 698 if (ret) 699 return ret; 700 701 name = binder_devices_param; 702 for (len = strcspn(name, ","); len > 0; len = strcspn(name, ",")) { 703 strscpy(device_info.name, name, len + 1); 704 ret = binderfs_binder_device_create(inode, NULL, &device_info); 705 if (ret) 706 return ret; 707 name += len; 708 if (*name == ',') 709 name++; 710 } 711 712 if (info->mount_opts.stats_mode == binderfs_stats_mode_global) 713 return init_binder_logs(sb); 714 715 return 0; 716} 717 718static int binderfs_fs_context_get_tree(struct fs_context *fc) 719{ 720 return get_tree_nodev(fc, binderfs_fill_super); 721} 722 723static void binderfs_fs_context_free(struct fs_context *fc) 724{ 725 struct binderfs_mount_opts *ctx = fc->fs_private; 726 727 kfree(ctx); 728} 729 730static const struct fs_context_operations binderfs_fs_context_ops = { 731 .free = binderfs_fs_context_free, 732 .get_tree = binderfs_fs_context_get_tree, 733 .parse_param = binderfs_fs_context_parse_param, 734 .reconfigure = binderfs_fs_context_reconfigure, 735}; 736 737static int binderfs_init_fs_context(struct fs_context *fc) 738{ 739 struct binderfs_mount_opts *ctx; 740 741 ctx = kzalloc(sizeof(struct binderfs_mount_opts), GFP_KERNEL); 742 if (!ctx) 743 return -ENOMEM; 744 745 ctx->max = BINDERFS_MAX_MINOR; 746 ctx->stats_mode = binderfs_stats_mode_unset; 747 748 fc->fs_private = ctx; 749 fc->ops = &binderfs_fs_context_ops; 750 751 return 0; 752} 753 754static void binderfs_kill_super(struct super_block *sb) 755{ 756 struct binderfs_info *info = sb->s_fs_info; 757 758 /* 759 * During inode eviction struct binderfs_info is needed. 760 * So first wipe the super_block then free struct binderfs_info. 761 */ 762 kill_litter_super(sb); 763 764 if (info && info->ipc_ns) 765 put_ipc_ns(info->ipc_ns); 766 767 kfree(info); 768} 769 770static struct file_system_type binder_fs_type = { 771 .name = "binder", 772 .init_fs_context = binderfs_init_fs_context, 773 .parameters = binderfs_fs_parameters, 774 .kill_sb = binderfs_kill_super, 775 .fs_flags = FS_USERNS_MOUNT, 776}; 777 778int __init init_binderfs(void) 779{ 780 int ret; 781 const char *name; 782 size_t len; 783 784 /* Verify that the default binderfs device names are valid. */ 785 name = binder_devices_param; 786 for (len = strcspn(name, ","); len > 0; len = strcspn(name, ",")) { 787 if (len > BINDERFS_MAX_NAME) 788 return -E2BIG; 789 name += len; 790 if (*name == ',') 791 name++; 792 } 793 794 /* Allocate new major number for binderfs. */ 795 ret = alloc_chrdev_region(&binderfs_dev, 0, BINDERFS_MAX_MINOR, 796 "binder"); 797 if (ret) 798 return ret; 799 800 ret = register_filesystem(&binder_fs_type); 801 if (ret) { 802 unregister_chrdev_region(binderfs_dev, BINDERFS_MAX_MINOR); 803 return ret; 804 } 805 806 return ret; 807} 808