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 struct binder_features { 62 bool oneway_spam_detection; 63 }; 64 65 static const struct constant_table binderfs_param_stats[] = { 66 { "global", binderfs_stats_mode_global }, 67 {} 68 }; 69 70 static const struct fs_parameter_spec binderfs_fs_parameters[] = { 71 fsparam_u32("max", Opt_max), 72 fsparam_enum("stats", Opt_stats_mode, binderfs_param_stats), 73 {} 74 }; 75 76 static struct binder_features binder_features = { 77 .oneway_spam_detection = true, 78 }; 79 80 static inline struct binderfs_info *BINDERFS_SB(const struct super_block *sb) 81 { 82 return sb->s_fs_info; 83 } 84 85 bool 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 */ 111 static 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->i_ctime = current_time(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; 210 211 err: 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 * binderfs_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 */ 233 static 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 } 257 258 static 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 } 278 279 static 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 } 309 310 static 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 } 322 323 static 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 } 340 341 static void binderfs_put_super(struct super_block *sb) 342 { 343 struct binderfs_info *info = sb->s_fs_info; 344 345 if (info && info->ipc_ns) 346 put_ipc_ns(info->ipc_ns); 347 348 kfree(info); 349 sb->s_fs_info = NULL; 350 } 351 352 static const struct super_operations binderfs_super_ops = { 353 .evict_inode = binderfs_evict_inode, 354 .show_options = binderfs_show_options, 355 .statfs = simple_statfs, 356 .put_super = binderfs_put_super, 357 }; 358 359 static inline bool is_binderfs_control_device(const struct dentry *dentry) 360 { 361 struct binderfs_info *info = dentry->d_sb->s_fs_info; 362 363 return info->control_dentry == dentry; 364 } 365 366 static int binderfs_rename(struct user_namespace *mnt_userns, 367 struct inode *old_dir, struct dentry *old_dentry, 368 struct inode *new_dir, struct dentry *new_dentry, 369 unsigned int flags) 370 { 371 if (is_binderfs_control_device(old_dentry) || 372 is_binderfs_control_device(new_dentry)) 373 return -EPERM; 374 375 return simple_rename(&init_user_ns, old_dir, old_dentry, new_dir, 376 new_dentry, flags); 377 } 378 379 static int binderfs_unlink(struct inode *dir, struct dentry *dentry) 380 { 381 if (is_binderfs_control_device(dentry)) 382 return -EPERM; 383 384 return simple_unlink(dir, dentry); 385 } 386 387 static const struct file_operations binder_ctl_fops = { 388 .owner = THIS_MODULE, 389 .open = nonseekable_open, 390 .unlocked_ioctl = binder_ctl_ioctl, 391 .compat_ioctl = binder_ctl_ioctl, 392 .llseek = noop_llseek, 393 }; 394 395 /** 396 * binderfs_binder_ctl_create - create a new binder-control device 397 * @sb: super block of the binderfs mount 398 * 399 * This function creates a new binder-control device node in the binderfs mount 400 * referred to by @sb. 401 * 402 * Return: 0 on success, negative errno on failure 403 */ 404 static int binderfs_binder_ctl_create(struct super_block *sb) 405 { 406 int minor, ret; 407 struct dentry *dentry; 408 struct binder_device *device; 409 struct inode *inode = NULL; 410 struct dentry *root = sb->s_root; 411 struct binderfs_info *info = sb->s_fs_info; 412 #if defined(CONFIG_IPC_NS) 413 bool use_reserve = (info->ipc_ns == &init_ipc_ns); 414 #else 415 bool use_reserve = true; 416 #endif 417 418 device = kzalloc(sizeof(*device), GFP_KERNEL); 419 if (!device) 420 return -ENOMEM; 421 422 /* If we have already created a binder-control node, return. */ 423 if (info->control_dentry) { 424 ret = 0; 425 goto out; 426 } 427 428 ret = -ENOMEM; 429 inode = new_inode(sb); 430 if (!inode) 431 goto out; 432 433 /* Reserve a new minor number for the new device. */ 434 mutex_lock(&binderfs_minors_mutex); 435 minor = ida_alloc_max(&binderfs_minors, 436 use_reserve ? BINDERFS_MAX_MINOR : 437 BINDERFS_MAX_MINOR_CAPPED, 438 GFP_KERNEL); 439 mutex_unlock(&binderfs_minors_mutex); 440 if (minor < 0) { 441 ret = minor; 442 goto out; 443 } 444 445 inode->i_ino = SECOND_INODE; 446 inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode); 447 init_special_inode(inode, S_IFCHR | 0600, 448 MKDEV(MAJOR(binderfs_dev), minor)); 449 inode->i_fop = &binder_ctl_fops; 450 inode->i_uid = info->root_uid; 451 inode->i_gid = info->root_gid; 452 453 refcount_set(&device->ref, 1); 454 device->binderfs_inode = inode; 455 device->miscdev.minor = minor; 456 457 dentry = d_alloc_name(root, "binder-control"); 458 if (!dentry) 459 goto out; 460 461 inode->i_private = device; 462 info->control_dentry = dentry; 463 d_add(dentry, inode); 464 465 return 0; 466 467 out: 468 kfree(device); 469 iput(inode); 470 471 return ret; 472 } 473 474 static const struct inode_operations binderfs_dir_inode_operations = { 475 .lookup = simple_lookup, 476 .rename = binderfs_rename, 477 .unlink = binderfs_unlink, 478 }; 479 480 static struct inode *binderfs_make_inode(struct super_block *sb, int mode) 481 { 482 struct inode *ret; 483 484 ret = new_inode(sb); 485 if (ret) { 486 ret->i_ino = iunique(sb, BINDERFS_MAX_MINOR + INODE_OFFSET); 487 ret->i_mode = mode; 488 ret->i_atime = ret->i_mtime = ret->i_ctime = current_time(ret); 489 } 490 return ret; 491 } 492 493 static struct dentry *binderfs_create_dentry(struct dentry *parent, 494 const char *name) 495 { 496 struct dentry *dentry; 497 498 dentry = lookup_one_len(name, parent, strlen(name)); 499 if (IS_ERR(dentry)) 500 return dentry; 501 502 /* Return error if the file/dir already exists. */ 503 if (d_really_is_positive(dentry)) { 504 dput(dentry); 505 return ERR_PTR(-EEXIST); 506 } 507 508 return dentry; 509 } 510 511 void binderfs_remove_file(struct dentry *dentry) 512 { 513 struct inode *parent_inode; 514 515 parent_inode = d_inode(dentry->d_parent); 516 inode_lock(parent_inode); 517 if (simple_positive(dentry)) { 518 dget(dentry); 519 simple_unlink(parent_inode, dentry); 520 d_delete(dentry); 521 dput(dentry); 522 } 523 inode_unlock(parent_inode); 524 } 525 526 struct dentry *binderfs_create_file(struct dentry *parent, const char *name, 527 const struct file_operations *fops, 528 void *data) 529 { 530 struct dentry *dentry; 531 struct inode *new_inode, *parent_inode; 532 struct super_block *sb; 533 534 parent_inode = d_inode(parent); 535 inode_lock(parent_inode); 536 537 dentry = binderfs_create_dentry(parent, name); 538 if (IS_ERR(dentry)) 539 goto out; 540 541 sb = parent_inode->i_sb; 542 new_inode = binderfs_make_inode(sb, S_IFREG | 0444); 543 if (!new_inode) { 544 dput(dentry); 545 dentry = ERR_PTR(-ENOMEM); 546 goto out; 547 } 548 549 new_inode->i_fop = fops; 550 new_inode->i_private = data; 551 d_instantiate(dentry, new_inode); 552 fsnotify_create(parent_inode, dentry); 553 554 out: 555 inode_unlock(parent_inode); 556 return dentry; 557 } 558 559 static struct dentry *binderfs_create_dir(struct dentry *parent, 560 const char *name) 561 { 562 struct dentry *dentry; 563 struct inode *new_inode, *parent_inode; 564 struct super_block *sb; 565 566 parent_inode = d_inode(parent); 567 inode_lock(parent_inode); 568 569 dentry = binderfs_create_dentry(parent, name); 570 if (IS_ERR(dentry)) 571 goto out; 572 573 sb = parent_inode->i_sb; 574 new_inode = binderfs_make_inode(sb, S_IFDIR | 0755); 575 if (!new_inode) { 576 dput(dentry); 577 dentry = ERR_PTR(-ENOMEM); 578 goto out; 579 } 580 581 new_inode->i_fop = &simple_dir_operations; 582 new_inode->i_op = &simple_dir_inode_operations; 583 584 set_nlink(new_inode, 2); 585 d_instantiate(dentry, new_inode); 586 inc_nlink(parent_inode); 587 fsnotify_mkdir(parent_inode, dentry); 588 589 out: 590 inode_unlock(parent_inode); 591 return dentry; 592 } 593 594 static int binder_features_show(struct seq_file *m, void *unused) 595 { 596 bool *feature = m->private; 597 598 seq_printf(m, "%d\n", *feature); 599 600 return 0; 601 } 602 DEFINE_SHOW_ATTRIBUTE(binder_features); 603 604 static int init_binder_features(struct super_block *sb) 605 { 606 struct dentry *dentry, *dir; 607 608 dir = binderfs_create_dir(sb->s_root, "features"); 609 if (IS_ERR(dir)) 610 return PTR_ERR(dir); 611 612 dentry = binderfs_create_file(dir, "oneway_spam_detection", 613 &binder_features_fops, 614 &binder_features.oneway_spam_detection); 615 if (IS_ERR(dentry)) 616 return PTR_ERR(dentry); 617 618 return 0; 619 } 620 621 static int init_binder_logs(struct super_block *sb) 622 { 623 struct dentry *binder_logs_root_dir, *dentry, *proc_log_dir; 624 struct binderfs_info *info; 625 int ret = 0; 626 627 binder_logs_root_dir = binderfs_create_dir(sb->s_root, 628 "binder_logs"); 629 if (IS_ERR(binder_logs_root_dir)) { 630 ret = PTR_ERR(binder_logs_root_dir); 631 goto out; 632 } 633 634 dentry = binderfs_create_file(binder_logs_root_dir, "stats", 635 &binder_stats_fops, NULL); 636 if (IS_ERR(dentry)) { 637 ret = PTR_ERR(dentry); 638 goto out; 639 } 640 641 dentry = binderfs_create_file(binder_logs_root_dir, "state", 642 &binder_state_fops, NULL); 643 if (IS_ERR(dentry)) { 644 ret = PTR_ERR(dentry); 645 goto out; 646 } 647 648 dentry = binderfs_create_file(binder_logs_root_dir, "transactions", 649 &binder_transactions_fops, NULL); 650 if (IS_ERR(dentry)) { 651 ret = PTR_ERR(dentry); 652 goto out; 653 } 654 655 dentry = binderfs_create_file(binder_logs_root_dir, 656 "transaction_log", 657 &binder_transaction_log_fops, 658 &binder_transaction_log); 659 if (IS_ERR(dentry)) { 660 ret = PTR_ERR(dentry); 661 goto out; 662 } 663 664 dentry = binderfs_create_file(binder_logs_root_dir, 665 "failed_transaction_log", 666 &binder_transaction_log_fops, 667 &binder_transaction_log_failed); 668 if (IS_ERR(dentry)) { 669 ret = PTR_ERR(dentry); 670 goto out; 671 } 672 673 proc_log_dir = binderfs_create_dir(binder_logs_root_dir, "proc"); 674 if (IS_ERR(proc_log_dir)) { 675 ret = PTR_ERR(proc_log_dir); 676 goto out; 677 } 678 info = sb->s_fs_info; 679 info->proc_log_dir = proc_log_dir; 680 681 out: 682 return ret; 683 } 684 685 static int binderfs_fill_super(struct super_block *sb, struct fs_context *fc) 686 { 687 int ret; 688 struct binderfs_info *info; 689 struct binderfs_mount_opts *ctx = fc->fs_private; 690 struct inode *inode = NULL; 691 struct binderfs_device device_info = {}; 692 const char *name; 693 size_t len; 694 695 sb->s_blocksize = PAGE_SIZE; 696 sb->s_blocksize_bits = PAGE_SHIFT; 697 698 /* 699 * The binderfs filesystem can be mounted by userns root in a 700 * non-initial userns. By default such mounts have the SB_I_NODEV flag 701 * set in s_iflags to prevent security issues where userns root can 702 * just create random device nodes via mknod() since it owns the 703 * filesystem mount. But binderfs does not allow to create any files 704 * including devices nodes. The only way to create binder devices nodes 705 * is through the binder-control device which userns root is explicitly 706 * allowed to do. So removing the SB_I_NODEV flag from s_iflags is both 707 * necessary and safe. 708 */ 709 sb->s_iflags &= ~SB_I_NODEV; 710 sb->s_iflags |= SB_I_NOEXEC; 711 sb->s_magic = BINDERFS_SUPER_MAGIC; 712 sb->s_op = &binderfs_super_ops; 713 sb->s_time_gran = 1; 714 715 sb->s_fs_info = kzalloc(sizeof(struct binderfs_info), GFP_KERNEL); 716 if (!sb->s_fs_info) 717 return -ENOMEM; 718 info = sb->s_fs_info; 719 720 info->ipc_ns = get_ipc_ns(current->nsproxy->ipc_ns); 721 722 info->root_gid = make_kgid(sb->s_user_ns, 0); 723 if (!gid_valid(info->root_gid)) 724 info->root_gid = GLOBAL_ROOT_GID; 725 info->root_uid = make_kuid(sb->s_user_ns, 0); 726 if (!uid_valid(info->root_uid)) 727 info->root_uid = GLOBAL_ROOT_UID; 728 info->mount_opts.max = ctx->max; 729 info->mount_opts.stats_mode = ctx->stats_mode; 730 731 inode = new_inode(sb); 732 if (!inode) 733 return -ENOMEM; 734 735 inode->i_ino = FIRST_INODE; 736 inode->i_fop = &simple_dir_operations; 737 inode->i_mode = S_IFDIR | 0755; 738 inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode); 739 inode->i_op = &binderfs_dir_inode_operations; 740 set_nlink(inode, 2); 741 742 sb->s_root = d_make_root(inode); 743 if (!sb->s_root) 744 return -ENOMEM; 745 746 ret = binderfs_binder_ctl_create(sb); 747 if (ret) 748 return ret; 749 750 name = binder_devices_param; 751 for (len = strcspn(name, ","); len > 0; len = strcspn(name, ",")) { 752 strscpy(device_info.name, name, len + 1); 753 ret = binderfs_binder_device_create(inode, NULL, &device_info); 754 if (ret) 755 return ret; 756 name += len; 757 if (*name == ',') 758 name++; 759 } 760 761 ret = init_binder_features(sb); 762 if (ret) 763 return ret; 764 765 if (info->mount_opts.stats_mode == binderfs_stats_mode_global) 766 return init_binder_logs(sb); 767 768 return 0; 769 } 770 771 static int binderfs_fs_context_get_tree(struct fs_context *fc) 772 { 773 return get_tree_nodev(fc, binderfs_fill_super); 774 } 775 776 static void binderfs_fs_context_free(struct fs_context *fc) 777 { 778 struct binderfs_mount_opts *ctx = fc->fs_private; 779 780 kfree(ctx); 781 } 782 783 static const struct fs_context_operations binderfs_fs_context_ops = { 784 .free = binderfs_fs_context_free, 785 .get_tree = binderfs_fs_context_get_tree, 786 .parse_param = binderfs_fs_context_parse_param, 787 .reconfigure = binderfs_fs_context_reconfigure, 788 }; 789 790 static int binderfs_init_fs_context(struct fs_context *fc) 791 { 792 struct binderfs_mount_opts *ctx; 793 794 ctx = kzalloc(sizeof(struct binderfs_mount_opts), GFP_KERNEL); 795 if (!ctx) 796 return -ENOMEM; 797 798 ctx->max = BINDERFS_MAX_MINOR; 799 ctx->stats_mode = binderfs_stats_mode_unset; 800 801 fc->fs_private = ctx; 802 fc->ops = &binderfs_fs_context_ops; 803 804 return 0; 805 } 806 807 static struct file_system_type binder_fs_type = { 808 .name = "binder", 809 .init_fs_context = binderfs_init_fs_context, 810 .parameters = binderfs_fs_parameters, 811 .kill_sb = kill_litter_super, 812 .fs_flags = FS_USERNS_MOUNT, 813 }; 814 815 int __init init_binderfs(void) 816 { 817 int ret; 818 const char *name; 819 size_t len; 820 821 /* Verify that the default binderfs device names are valid. */ 822 name = binder_devices_param; 823 for (len = strcspn(name, ","); len > 0; len = strcspn(name, ",")) { 824 if (len > BINDERFS_MAX_NAME) 825 return -E2BIG; 826 name += len; 827 if (*name == ',') 828 name++; 829 } 830 831 /* Allocate new major number for binderfs. */ 832 ret = alloc_chrdev_region(&binderfs_dev, 0, BINDERFS_MAX_MINOR, 833 "binder"); 834 if (ret) 835 return ret; 836 837 ret = register_filesystem(&binder_fs_type); 838 if (ret) { 839 unregister_chrdev_region(binderfs_dev, BINDERFS_MAX_MINOR); 840 return ret; 841 } 842 843 return ret; 844 } 845