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/sched.h> 23#include <linux/seq_file.h> 24#include <linux/slab.h> 25#include <linux/spinlock_types.h> 26#include <linux/stddef.h> 27#include <linux/string.h> 28#include <linux/types.h> 29#include <linux/uaccess.h> 30#include <linux/user_namespace.h> 31#include <linux/xarray.h> 32#include <uapi/asm-generic/errno-base.h> 33#include <uapi/linux/android/binder.h> 34#include <uapi/linux/android/binderfs.h> 35 36#include "binder_internal.h" 37 38#define FIRST_INODE 1 39#define SECOND_INODE 2 40#define INODE_OFFSET 3 41#define BINDERFS_MAX_MINOR (1U << MINORBITS) 42/* Ensure that the initial ipc namespace always has devices available. */ 43#define BINDERFS_MAX_MINOR_CAPPED (BINDERFS_MAX_MINOR - 4) 44 45static dev_t binderfs_dev; 46static DEFINE_MUTEX(binderfs_minors_mutex); 47static DEFINE_IDA(binderfs_minors); 48 49enum binderfs_param { 50 Opt_max, 51 Opt_stats_mode, 52}; 53 54enum binderfs_stats_mode { 55 binderfs_stats_mode_unset, 56 binderfs_stats_mode_global, 57}; 58 59struct binder_features { 60 bool oneway_spam_detection; 61 bool extended_error; 62}; 63 64static const struct constant_table binderfs_param_stats[] = { 65 { "global", binderfs_stats_mode_global }, 66 {} 67}; 68 69static const struct fs_parameter_spec binderfs_fs_parameters[] = { 70 fsparam_u32("max", Opt_max), 71 fsparam_enum("stats", Opt_stats_mode, binderfs_param_stats), 72 {} 73}; 74 75static struct binder_features binder_features = { 76 .oneway_spam_detection = true, 77 .extended_error = true, 78}; 79 80static inline struct binderfs_info *BINDERFS_SB(const struct super_block *sb) 81{ 82 return sb->s_fs_info; 83} 84 85bool is_binderfs_device(const struct inode *inode) 86{ 87 if (inode->i_sb->s_magic == BINDERFS_SUPER_MAGIC) 88 return true; 89 90 return false; 91} 92 93/** 94 * binderfs_binder_device_create - allocate inode from super block of a 95 * binderfs mount 96 * @ref_inode: inode from wich the super block will be taken 97 * @userp: buffer to copy information about new device for userspace to 98 * @req: struct binderfs_device as copied from userspace 99 * 100 * This function allocates a new binder_device and reserves a new minor 101 * number for it. 102 * Minor numbers are limited and tracked globally in binderfs_minors. The 103 * function will stash a struct binder_device for the specific binder 104 * device in i_private of the inode. 105 * It will go on to allocate a new inode from the super block of the 106 * filesystem mount, stash a struct binder_device in its i_private field 107 * and attach a dentry to that inode. 108 * 109 * Return: 0 on success, negative errno on failure 110 */ 111static int binderfs_binder_device_create(struct inode *ref_inode, 112 struct binderfs_device __user *userp, 113 struct binderfs_device *req) 114{ 115 int minor, ret; 116 struct dentry *dentry, *root; 117 struct binder_device *device; 118 char *name = NULL; 119 size_t name_len; 120 struct inode *inode = NULL; 121 struct super_block *sb = ref_inode->i_sb; 122 struct binderfs_info *info = sb->s_fs_info; 123#if defined(CONFIG_IPC_NS) 124 bool use_reserve = (info->ipc_ns == &init_ipc_ns); 125#else 126 bool use_reserve = true; 127#endif 128 129 /* Reserve new minor number for the new device. */ 130 mutex_lock(&binderfs_minors_mutex); 131 if (++info->device_count <= info->mount_opts.max) 132 minor = ida_alloc_max(&binderfs_minors, 133 use_reserve ? BINDERFS_MAX_MINOR : 134 BINDERFS_MAX_MINOR_CAPPED, 135 GFP_KERNEL); 136 else 137 minor = -ENOSPC; 138 if (minor < 0) { 139 --info->device_count; 140 mutex_unlock(&binderfs_minors_mutex); 141 return minor; 142 } 143 mutex_unlock(&binderfs_minors_mutex); 144 145 ret = -ENOMEM; 146 device = kzalloc(sizeof(*device), GFP_KERNEL); 147 if (!device) 148 goto err; 149 150 inode = new_inode(sb); 151 if (!inode) 152 goto err; 153 154 inode->i_ino = minor + INODE_OFFSET; 155 inode->i_mtime = inode->i_atime = inode_set_ctime_current(inode); 156 init_special_inode(inode, S_IFCHR | 0600, 157 MKDEV(MAJOR(binderfs_dev), minor)); 158 inode->i_fop = &binder_fops; 159 inode->i_uid = info->root_uid; 160 inode->i_gid = info->root_gid; 161 162 req->name[BINDERFS_MAX_NAME] = '\0'; /* NUL-terminate */ 163 name_len = strlen(req->name); 164 /* Make sure to include terminating NUL byte */ 165 name = kmemdup(req->name, name_len + 1, GFP_KERNEL); 166 if (!name) 167 goto err; 168 169 refcount_set(&device->ref, 1); 170 device->binderfs_inode = inode; 171 device->context.binder_context_mgr_uid = INVALID_UID; 172 device->context.name = name; 173 device->miscdev.name = name; 174 device->miscdev.minor = minor; 175 mutex_init(&device->context.context_mgr_node_lock); 176 177 req->major = MAJOR(binderfs_dev); 178 req->minor = minor; 179 180 if (userp && copy_to_user(userp, req, sizeof(*req))) { 181 ret = -EFAULT; 182 goto err; 183 } 184 185 root = sb->s_root; 186 inode_lock(d_inode(root)); 187 188 /* look it up */ 189 dentry = lookup_one_len(name, root, name_len); 190 if (IS_ERR(dentry)) { 191 inode_unlock(d_inode(root)); 192 ret = PTR_ERR(dentry); 193 goto err; 194 } 195 196 if (d_really_is_positive(dentry)) { 197 /* already exists */ 198 dput(dentry); 199 inode_unlock(d_inode(root)); 200 ret = -EEXIST; 201 goto err; 202 } 203 204 inode->i_private = device; 205 d_instantiate(dentry, inode); 206 fsnotify_create(root->d_inode, dentry); 207 inode_unlock(d_inode(root)); 208 209 return 0; 210 211err: 212 kfree(name); 213 kfree(device); 214 mutex_lock(&binderfs_minors_mutex); 215 --info->device_count; 216 ida_free(&binderfs_minors, minor); 217 mutex_unlock(&binderfs_minors_mutex); 218 iput(inode); 219 220 return ret; 221} 222 223/** 224 * binder_ctl_ioctl - handle binder device node allocation requests 225 * 226 * The request handler for the binder-control device. All requests operate on 227 * the binderfs mount the binder-control device resides in: 228 * - BINDER_CTL_ADD 229 * Allocate a new binder device. 230 * 231 * Return: %0 on success, negative errno on failure. 232 */ 233static long binder_ctl_ioctl(struct file *file, unsigned int cmd, 234 unsigned long arg) 235{ 236 int ret = -EINVAL; 237 struct inode *inode = file_inode(file); 238 struct binderfs_device __user *device = (struct binderfs_device __user *)arg; 239 struct binderfs_device device_req; 240 241 switch (cmd) { 242 case BINDER_CTL_ADD: 243 ret = copy_from_user(&device_req, device, sizeof(device_req)); 244 if (ret) { 245 ret = -EFAULT; 246 break; 247 } 248 249 ret = binderfs_binder_device_create(inode, device, &device_req); 250 break; 251 default: 252 break; 253 } 254 255 return ret; 256} 257 258static void binderfs_evict_inode(struct inode *inode) 259{ 260 struct binder_device *device = inode->i_private; 261 struct binderfs_info *info = BINDERFS_SB(inode->i_sb); 262 263 clear_inode(inode); 264 265 if (!S_ISCHR(inode->i_mode) || !device) 266 return; 267 268 mutex_lock(&binderfs_minors_mutex); 269 --info->device_count; 270 ida_free(&binderfs_minors, device->miscdev.minor); 271 mutex_unlock(&binderfs_minors_mutex); 272 273 if (refcount_dec_and_test(&device->ref)) { 274 kfree(device->context.name); 275 kfree(device); 276 } 277} 278 279static int binderfs_fs_context_parse_param(struct fs_context *fc, 280 struct fs_parameter *param) 281{ 282 int opt; 283 struct binderfs_mount_opts *ctx = fc->fs_private; 284 struct fs_parse_result result; 285 286 opt = fs_parse(fc, binderfs_fs_parameters, param, &result); 287 if (opt < 0) 288 return opt; 289 290 switch (opt) { 291 case Opt_max: 292 if (result.uint_32 > BINDERFS_MAX_MINOR) 293 return invalfc(fc, "Bad value for '%s'", param->key); 294 295 ctx->max = result.uint_32; 296 break; 297 case Opt_stats_mode: 298 if (!capable(CAP_SYS_ADMIN)) 299 return -EPERM; 300 301 ctx->stats_mode = result.uint_32; 302 break; 303 default: 304 return invalfc(fc, "Unsupported parameter '%s'", param->key); 305 } 306 307 return 0; 308} 309 310static int binderfs_fs_context_reconfigure(struct fs_context *fc) 311{ 312 struct binderfs_mount_opts *ctx = fc->fs_private; 313 struct binderfs_info *info = BINDERFS_SB(fc->root->d_sb); 314 315 if (info->mount_opts.stats_mode != ctx->stats_mode) 316 return invalfc(fc, "Binderfs stats mode cannot be changed during a remount"); 317 318 info->mount_opts.stats_mode = ctx->stats_mode; 319 info->mount_opts.max = ctx->max; 320 return 0; 321} 322 323static int binderfs_show_options(struct seq_file *seq, struct dentry *root) 324{ 325 struct binderfs_info *info = BINDERFS_SB(root->d_sb); 326 327 if (info->mount_opts.max <= BINDERFS_MAX_MINOR) 328 seq_printf(seq, ",max=%d", info->mount_opts.max); 329 330 switch (info->mount_opts.stats_mode) { 331 case binderfs_stats_mode_unset: 332 break; 333 case binderfs_stats_mode_global: 334 seq_printf(seq, ",stats=global"); 335 break; 336 } 337 338 return 0; 339} 340 341static const struct super_operations binderfs_super_ops = { 342 .evict_inode = binderfs_evict_inode, 343 .show_options = binderfs_show_options, 344 .statfs = simple_statfs, 345}; 346 347static inline bool is_binderfs_control_device(const struct dentry *dentry) 348{ 349 struct binderfs_info *info = dentry->d_sb->s_fs_info; 350 351 return info->control_dentry == dentry; 352} 353 354static int binderfs_rename(struct mnt_idmap *idmap, 355 struct inode *old_dir, struct dentry *old_dentry, 356 struct inode *new_dir, struct dentry *new_dentry, 357 unsigned int flags) 358{ 359 if (is_binderfs_control_device(old_dentry) || 360 is_binderfs_control_device(new_dentry)) 361 return -EPERM; 362 363 return simple_rename(idmap, old_dir, old_dentry, new_dir, 364 new_dentry, flags); 365} 366 367static int binderfs_unlink(struct inode *dir, struct dentry *dentry) 368{ 369 if (is_binderfs_control_device(dentry)) 370 return -EPERM; 371 372 return simple_unlink(dir, dentry); 373} 374 375static const struct file_operations binder_ctl_fops = { 376 .owner = THIS_MODULE, 377 .open = nonseekable_open, 378 .unlocked_ioctl = binder_ctl_ioctl, 379 .compat_ioctl = binder_ctl_ioctl, 380 .llseek = noop_llseek, 381}; 382 383/** 384 * binderfs_binder_ctl_create - create a new binder-control device 385 * @sb: super block of the binderfs mount 386 * 387 * This function creates a new binder-control device node in the binderfs mount 388 * referred to by @sb. 389 * 390 * Return: 0 on success, negative errno on failure 391 */ 392static int binderfs_binder_ctl_create(struct super_block *sb) 393{ 394 int minor, ret; 395 struct dentry *dentry; 396 struct binder_device *device; 397 struct inode *inode = NULL; 398 struct dentry *root = sb->s_root; 399 struct binderfs_info *info = sb->s_fs_info; 400#if defined(CONFIG_IPC_NS) 401 bool use_reserve = (info->ipc_ns == &init_ipc_ns); 402#else 403 bool use_reserve = true; 404#endif 405 406 device = kzalloc(sizeof(*device), GFP_KERNEL); 407 if (!device) 408 return -ENOMEM; 409 410 /* If we have already created a binder-control node, return. */ 411 if (info->control_dentry) { 412 ret = 0; 413 goto out; 414 } 415 416 ret = -ENOMEM; 417 inode = new_inode(sb); 418 if (!inode) 419 goto out; 420 421 /* Reserve a new minor number for the new device. */ 422 mutex_lock(&binderfs_minors_mutex); 423 minor = ida_alloc_max(&binderfs_minors, 424 use_reserve ? BINDERFS_MAX_MINOR : 425 BINDERFS_MAX_MINOR_CAPPED, 426 GFP_KERNEL); 427 mutex_unlock(&binderfs_minors_mutex); 428 if (minor < 0) { 429 ret = minor; 430 goto out; 431 } 432 433 inode->i_ino = SECOND_INODE; 434 inode->i_mtime = inode->i_atime = inode_set_ctime_current(inode); 435 init_special_inode(inode, S_IFCHR | 0600, 436 MKDEV(MAJOR(binderfs_dev), minor)); 437 inode->i_fop = &binder_ctl_fops; 438 inode->i_uid = info->root_uid; 439 inode->i_gid = info->root_gid; 440 441 refcount_set(&device->ref, 1); 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 455out: 456 kfree(device); 457 iput(inode); 458 459 return ret; 460} 461 462static const struct inode_operations binderfs_dir_inode_operations = { 463 .lookup = simple_lookup, 464 .rename = binderfs_rename, 465 .unlink = binderfs_unlink, 466}; 467 468static 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 = inode_set_ctime_current(ret); 477 } 478 return ret; 479} 480 481static 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 499void 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 514struct 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 542out: 543 inode_unlock(parent_inode); 544 return dentry; 545} 546 547static 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 577out: 578 inode_unlock(parent_inode); 579 return dentry; 580} 581 582static int binder_features_show(struct seq_file *m, void *unused) 583{ 584 bool *feature = m->private; 585 586 seq_printf(m, "%d\n", *feature); 587 588 return 0; 589} 590DEFINE_SHOW_ATTRIBUTE(binder_features); 591 592static int init_binder_features(struct super_block *sb) 593{ 594 struct dentry *dentry, *dir; 595 596 dir = binderfs_create_dir(sb->s_root, "features"); 597 if (IS_ERR(dir)) 598 return PTR_ERR(dir); 599 600 dentry = binderfs_create_file(dir, "oneway_spam_detection", 601 &binder_features_fops, 602 &binder_features.oneway_spam_detection); 603 if (IS_ERR(dentry)) 604 return PTR_ERR(dentry); 605 606 dentry = binderfs_create_file(dir, "extended_error", 607 &binder_features_fops, 608 &binder_features.extended_error); 609 if (IS_ERR(dentry)) 610 return PTR_ERR(dentry); 611 612 return 0; 613} 614 615static int init_binder_logs(struct super_block *sb) 616{ 617 struct dentry *binder_logs_root_dir, *dentry, *proc_log_dir; 618 const struct binder_debugfs_entry *db_entry; 619 struct binderfs_info *info; 620 int ret = 0; 621 622 binder_logs_root_dir = binderfs_create_dir(sb->s_root, 623 "binder_logs"); 624 if (IS_ERR(binder_logs_root_dir)) { 625 ret = PTR_ERR(binder_logs_root_dir); 626 goto out; 627 } 628 629 binder_for_each_debugfs_entry(db_entry) { 630 dentry = binderfs_create_file(binder_logs_root_dir, 631 db_entry->name, 632 db_entry->fops, 633 db_entry->data); 634 if (IS_ERR(dentry)) { 635 ret = PTR_ERR(dentry); 636 goto out; 637 } 638 } 639 640 proc_log_dir = binderfs_create_dir(binder_logs_root_dir, "proc"); 641 if (IS_ERR(proc_log_dir)) { 642 ret = PTR_ERR(proc_log_dir); 643 goto out; 644 } 645 info = sb->s_fs_info; 646 info->proc_log_dir = proc_log_dir; 647 648out: 649 return ret; 650} 651 652static int binderfs_fill_super(struct super_block *sb, struct fs_context *fc) 653{ 654 int ret; 655 struct binderfs_info *info; 656 struct binderfs_mount_opts *ctx = fc->fs_private; 657 struct inode *inode = NULL; 658 struct binderfs_device device_info = {}; 659 const char *name; 660 size_t len; 661 662 sb->s_blocksize = PAGE_SIZE; 663 sb->s_blocksize_bits = PAGE_SHIFT; 664 665 /* 666 * The binderfs filesystem can be mounted by userns root in a 667 * non-initial userns. By default such mounts have the SB_I_NODEV flag 668 * set in s_iflags to prevent security issues where userns root can 669 * just create random device nodes via mknod() since it owns the 670 * filesystem mount. But binderfs does not allow to create any files 671 * including devices nodes. The only way to create binder devices nodes 672 * is through the binder-control device which userns root is explicitly 673 * allowed to do. So removing the SB_I_NODEV flag from s_iflags is both 674 * necessary and safe. 675 */ 676 sb->s_iflags &= ~SB_I_NODEV; 677 sb->s_iflags |= SB_I_NOEXEC; 678 sb->s_magic = BINDERFS_SUPER_MAGIC; 679 sb->s_op = &binderfs_super_ops; 680 sb->s_time_gran = 1; 681 682 sb->s_fs_info = kzalloc(sizeof(struct binderfs_info), GFP_KERNEL); 683 if (!sb->s_fs_info) 684 return -ENOMEM; 685 info = sb->s_fs_info; 686 687 info->ipc_ns = get_ipc_ns(current->nsproxy->ipc_ns); 688 689 info->root_gid = make_kgid(sb->s_user_ns, 0); 690 if (!gid_valid(info->root_gid)) 691 info->root_gid = GLOBAL_ROOT_GID; 692 info->root_uid = make_kuid(sb->s_user_ns, 0); 693 if (!uid_valid(info->root_uid)) 694 info->root_uid = GLOBAL_ROOT_UID; 695 info->mount_opts.max = ctx->max; 696 info->mount_opts.stats_mode = ctx->stats_mode; 697 698 inode = new_inode(sb); 699 if (!inode) 700 return -ENOMEM; 701 702 inode->i_ino = FIRST_INODE; 703 inode->i_fop = &simple_dir_operations; 704 inode->i_mode = S_IFDIR | 0755; 705 inode->i_mtime = inode->i_atime = inode_set_ctime_current(inode); 706 inode->i_op = &binderfs_dir_inode_operations; 707 set_nlink(inode, 2); 708 709 sb->s_root = d_make_root(inode); 710 if (!sb->s_root) 711 return -ENOMEM; 712 713 ret = binderfs_binder_ctl_create(sb); 714 if (ret) 715 return ret; 716 717 name = binder_devices_param; 718 for (len = strcspn(name, ","); len > 0; len = strcspn(name, ",")) { 719 strscpy(device_info.name, name, len + 1); 720 ret = binderfs_binder_device_create(inode, NULL, &device_info); 721 if (ret) 722 return ret; 723 name += len; 724 if (*name == ',') 725 name++; 726 } 727 728 ret = init_binder_features(sb); 729 if (ret) 730 return ret; 731 732 if (info->mount_opts.stats_mode == binderfs_stats_mode_global) 733 return init_binder_logs(sb); 734 735 return 0; 736} 737 738static int binderfs_fs_context_get_tree(struct fs_context *fc) 739{ 740 return get_tree_nodev(fc, binderfs_fill_super); 741} 742 743static void binderfs_fs_context_free(struct fs_context *fc) 744{ 745 struct binderfs_mount_opts *ctx = fc->fs_private; 746 747 kfree(ctx); 748} 749 750static const struct fs_context_operations binderfs_fs_context_ops = { 751 .free = binderfs_fs_context_free, 752 .get_tree = binderfs_fs_context_get_tree, 753 .parse_param = binderfs_fs_context_parse_param, 754 .reconfigure = binderfs_fs_context_reconfigure, 755}; 756 757static int binderfs_init_fs_context(struct fs_context *fc) 758{ 759 struct binderfs_mount_opts *ctx; 760 761 ctx = kzalloc(sizeof(struct binderfs_mount_opts), GFP_KERNEL); 762 if (!ctx) 763 return -ENOMEM; 764 765 ctx->max = BINDERFS_MAX_MINOR; 766 ctx->stats_mode = binderfs_stats_mode_unset; 767 768 fc->fs_private = ctx; 769 fc->ops = &binderfs_fs_context_ops; 770 771 return 0; 772} 773 774static void binderfs_kill_super(struct super_block *sb) 775{ 776 struct binderfs_info *info = sb->s_fs_info; 777 778 /* 779 * During inode eviction struct binderfs_info is needed. 780 * So first wipe the super_block then free struct binderfs_info. 781 */ 782 kill_litter_super(sb); 783 784 if (info && info->ipc_ns) 785 put_ipc_ns(info->ipc_ns); 786 787 kfree(info); 788} 789 790static struct file_system_type binder_fs_type = { 791 .name = "binder", 792 .init_fs_context = binderfs_init_fs_context, 793 .parameters = binderfs_fs_parameters, 794 .kill_sb = binderfs_kill_super, 795 .fs_flags = FS_USERNS_MOUNT, 796}; 797 798int __init init_binderfs(void) 799{ 800 int ret; 801 const char *name; 802 size_t len; 803 804 /* Verify that the default binderfs device names are valid. */ 805 name = binder_devices_param; 806 for (len = strcspn(name, ","); len > 0; len = strcspn(name, ",")) { 807 if (len > BINDERFS_MAX_NAME) 808 return -E2BIG; 809 name += len; 810 if (*name == ',') 811 name++; 812 } 813 814 /* Allocate new major number for binderfs. */ 815 ret = alloc_chrdev_region(&binderfs_dev, 0, BINDERFS_MAX_MINOR, 816 "binder"); 817 if (ret) 818 return ret; 819 820 ret = register_filesystem(&binder_fs_type); 821 if (ret) { 822 unregister_chrdev_region(binderfs_dev, BINDERFS_MAX_MINOR); 823 return ret; 824 } 825 826 return ret; 827} 828