Loading...
Note: File does not exist in v3.1.
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 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
344static 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
351static inline bool is_binderfs_control_device(const struct dentry *dentry)
352{
353 struct binderfs_info *info = dentry->d_sb->s_fs_info;
354
355 return info->control_dentry == dentry;
356}
357
358static int binderfs_rename(struct user_namespace *mnt_userns,
359 struct inode *old_dir, struct dentry *old_dentry,
360 struct inode *new_dir, struct dentry *new_dentry,
361 unsigned int flags)
362{
363 if (is_binderfs_control_device(old_dentry) ||
364 is_binderfs_control_device(new_dentry))
365 return -EPERM;
366
367 return simple_rename(&init_user_ns, old_dir, old_dentry, new_dir,
368 new_dentry, flags);
369}
370
371static int binderfs_unlink(struct inode *dir, struct dentry *dentry)
372{
373 if (is_binderfs_control_device(dentry))
374 return -EPERM;
375
376 return simple_unlink(dir, dentry);
377}
378
379static const struct file_operations binder_ctl_fops = {
380 .owner = THIS_MODULE,
381 .open = nonseekable_open,
382 .unlocked_ioctl = binder_ctl_ioctl,
383 .compat_ioctl = binder_ctl_ioctl,
384 .llseek = noop_llseek,
385};
386
387/**
388 * binderfs_binder_ctl_create - create a new binder-control device
389 * @sb: super block of the binderfs mount
390 *
391 * This function creates a new binder-control device node in the binderfs mount
392 * referred to by @sb.
393 *
394 * Return: 0 on success, negative errno on failure
395 */
396static int binderfs_binder_ctl_create(struct super_block *sb)
397{
398 int minor, ret;
399 struct dentry *dentry;
400 struct binder_device *device;
401 struct inode *inode = NULL;
402 struct dentry *root = sb->s_root;
403 struct binderfs_info *info = sb->s_fs_info;
404#if defined(CONFIG_IPC_NS)
405 bool use_reserve = (info->ipc_ns == &init_ipc_ns);
406#else
407 bool use_reserve = true;
408#endif
409
410 device = kzalloc(sizeof(*device), GFP_KERNEL);
411 if (!device)
412 return -ENOMEM;
413
414 /* If we have already created a binder-control node, return. */
415 if (info->control_dentry) {
416 ret = 0;
417 goto out;
418 }
419
420 ret = -ENOMEM;
421 inode = new_inode(sb);
422 if (!inode)
423 goto out;
424
425 /* Reserve a new minor number for the new device. */
426 mutex_lock(&binderfs_minors_mutex);
427 minor = ida_alloc_max(&binderfs_minors,
428 use_reserve ? BINDERFS_MAX_MINOR :
429 BINDERFS_MAX_MINOR_CAPPED,
430 GFP_KERNEL);
431 mutex_unlock(&binderfs_minors_mutex);
432 if (minor < 0) {
433 ret = minor;
434 goto out;
435 }
436
437 inode->i_ino = SECOND_INODE;
438 inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
439 init_special_inode(inode, S_IFCHR | 0600,
440 MKDEV(MAJOR(binderfs_dev), minor));
441 inode->i_fop = &binder_ctl_fops;
442 inode->i_uid = info->root_uid;
443 inode->i_gid = info->root_gid;
444
445 refcount_set(&device->ref, 1);
446 device->binderfs_inode = inode;
447 device->miscdev.minor = minor;
448
449 dentry = d_alloc_name(root, "binder-control");
450 if (!dentry)
451 goto out;
452
453 inode->i_private = device;
454 info->control_dentry = dentry;
455 d_add(dentry, inode);
456
457 return 0;
458
459out:
460 kfree(device);
461 iput(inode);
462
463 return ret;
464}
465
466static const struct inode_operations binderfs_dir_inode_operations = {
467 .lookup = simple_lookup,
468 .rename = binderfs_rename,
469 .unlink = binderfs_unlink,
470};
471
472static struct inode *binderfs_make_inode(struct super_block *sb, int mode)
473{
474 struct inode *ret;
475
476 ret = new_inode(sb);
477 if (ret) {
478 ret->i_ino = iunique(sb, BINDERFS_MAX_MINOR + INODE_OFFSET);
479 ret->i_mode = mode;
480 ret->i_atime = ret->i_mtime = ret->i_ctime = current_time(ret);
481 }
482 return ret;
483}
484
485static struct dentry *binderfs_create_dentry(struct dentry *parent,
486 const char *name)
487{
488 struct dentry *dentry;
489
490 dentry = lookup_one_len(name, parent, strlen(name));
491 if (IS_ERR(dentry))
492 return dentry;
493
494 /* Return error if the file/dir already exists. */
495 if (d_really_is_positive(dentry)) {
496 dput(dentry);
497 return ERR_PTR(-EEXIST);
498 }
499
500 return dentry;
501}
502
503void binderfs_remove_file(struct dentry *dentry)
504{
505 struct inode *parent_inode;
506
507 parent_inode = d_inode(dentry->d_parent);
508 inode_lock(parent_inode);
509 if (simple_positive(dentry)) {
510 dget(dentry);
511 simple_unlink(parent_inode, dentry);
512 d_delete(dentry);
513 dput(dentry);
514 }
515 inode_unlock(parent_inode);
516}
517
518struct dentry *binderfs_create_file(struct dentry *parent, const char *name,
519 const struct file_operations *fops,
520 void *data)
521{
522 struct dentry *dentry;
523 struct inode *new_inode, *parent_inode;
524 struct super_block *sb;
525
526 parent_inode = d_inode(parent);
527 inode_lock(parent_inode);
528
529 dentry = binderfs_create_dentry(parent, name);
530 if (IS_ERR(dentry))
531 goto out;
532
533 sb = parent_inode->i_sb;
534 new_inode = binderfs_make_inode(sb, S_IFREG | 0444);
535 if (!new_inode) {
536 dput(dentry);
537 dentry = ERR_PTR(-ENOMEM);
538 goto out;
539 }
540
541 new_inode->i_fop = fops;
542 new_inode->i_private = data;
543 d_instantiate(dentry, new_inode);
544 fsnotify_create(parent_inode, dentry);
545
546out:
547 inode_unlock(parent_inode);
548 return dentry;
549}
550
551static struct dentry *binderfs_create_dir(struct dentry *parent,
552 const char *name)
553{
554 struct dentry *dentry;
555 struct inode *new_inode, *parent_inode;
556 struct super_block *sb;
557
558 parent_inode = d_inode(parent);
559 inode_lock(parent_inode);
560
561 dentry = binderfs_create_dentry(parent, name);
562 if (IS_ERR(dentry))
563 goto out;
564
565 sb = parent_inode->i_sb;
566 new_inode = binderfs_make_inode(sb, S_IFDIR | 0755);
567 if (!new_inode) {
568 dput(dentry);
569 dentry = ERR_PTR(-ENOMEM);
570 goto out;
571 }
572
573 new_inode->i_fop = &simple_dir_operations;
574 new_inode->i_op = &simple_dir_inode_operations;
575
576 set_nlink(new_inode, 2);
577 d_instantiate(dentry, new_inode);
578 inc_nlink(parent_inode);
579 fsnotify_mkdir(parent_inode, dentry);
580
581out:
582 inode_unlock(parent_inode);
583 return dentry;
584}
585
586static int init_binder_logs(struct super_block *sb)
587{
588 struct dentry *binder_logs_root_dir, *dentry, *proc_log_dir;
589 struct binderfs_info *info;
590 int ret = 0;
591
592 binder_logs_root_dir = binderfs_create_dir(sb->s_root,
593 "binder_logs");
594 if (IS_ERR(binder_logs_root_dir)) {
595 ret = PTR_ERR(binder_logs_root_dir);
596 goto out;
597 }
598
599 dentry = binderfs_create_file(binder_logs_root_dir, "stats",
600 &binder_stats_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, "state",
607 &binder_state_fops, NULL);
608 if (IS_ERR(dentry)) {
609 ret = PTR_ERR(dentry);
610 goto out;
611 }
612
613 dentry = binderfs_create_file(binder_logs_root_dir, "transactions",
614 &binder_transactions_fops, NULL);
615 if (IS_ERR(dentry)) {
616 ret = PTR_ERR(dentry);
617 goto out;
618 }
619
620 dentry = binderfs_create_file(binder_logs_root_dir,
621 "transaction_log",
622 &binder_transaction_log_fops,
623 &binder_transaction_log);
624 if (IS_ERR(dentry)) {
625 ret = PTR_ERR(dentry);
626 goto out;
627 }
628
629 dentry = binderfs_create_file(binder_logs_root_dir,
630 "failed_transaction_log",
631 &binder_transaction_log_fops,
632 &binder_transaction_log_failed);
633 if (IS_ERR(dentry)) {
634 ret = PTR_ERR(dentry);
635 goto out;
636 }
637
638 proc_log_dir = binderfs_create_dir(binder_logs_root_dir, "proc");
639 if (IS_ERR(proc_log_dir)) {
640 ret = PTR_ERR(proc_log_dir);
641 goto out;
642 }
643 info = sb->s_fs_info;
644 info->proc_log_dir = proc_log_dir;
645
646out:
647 return ret;
648}
649
650static int binderfs_fill_super(struct super_block *sb, struct fs_context *fc)
651{
652 int ret;
653 struct binderfs_info *info;
654 struct binderfs_mount_opts *ctx = fc->fs_private;
655 struct inode *inode = NULL;
656 struct binderfs_device device_info = {};
657 const char *name;
658 size_t len;
659
660 sb->s_blocksize = PAGE_SIZE;
661 sb->s_blocksize_bits = PAGE_SHIFT;
662
663 /*
664 * The binderfs filesystem can be mounted by userns root in a
665 * non-initial userns. By default such mounts have the SB_I_NODEV flag
666 * set in s_iflags to prevent security issues where userns root can
667 * just create random device nodes via mknod() since it owns the
668 * filesystem mount. But binderfs does not allow to create any files
669 * including devices nodes. The only way to create binder devices nodes
670 * is through the binder-control device which userns root is explicitly
671 * allowed to do. So removing the SB_I_NODEV flag from s_iflags is both
672 * necessary and safe.
673 */
674 sb->s_iflags &= ~SB_I_NODEV;
675 sb->s_iflags |= SB_I_NOEXEC;
676 sb->s_magic = BINDERFS_SUPER_MAGIC;
677 sb->s_op = &binderfs_super_ops;
678 sb->s_time_gran = 1;
679
680 sb->s_fs_info = kzalloc(sizeof(struct binderfs_info), GFP_KERNEL);
681 if (!sb->s_fs_info)
682 return -ENOMEM;
683 info = sb->s_fs_info;
684
685 info->ipc_ns = get_ipc_ns(current->nsproxy->ipc_ns);
686
687 info->root_gid = make_kgid(sb->s_user_ns, 0);
688 if (!gid_valid(info->root_gid))
689 info->root_gid = GLOBAL_ROOT_GID;
690 info->root_uid = make_kuid(sb->s_user_ns, 0);
691 if (!uid_valid(info->root_uid))
692 info->root_uid = GLOBAL_ROOT_UID;
693 info->mount_opts.max = ctx->max;
694 info->mount_opts.stats_mode = ctx->stats_mode;
695
696 inode = new_inode(sb);
697 if (!inode)
698 return -ENOMEM;
699
700 inode->i_ino = FIRST_INODE;
701 inode->i_fop = &simple_dir_operations;
702 inode->i_mode = S_IFDIR | 0755;
703 inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
704 inode->i_op = &binderfs_dir_inode_operations;
705 set_nlink(inode, 2);
706
707 sb->s_root = d_make_root(inode);
708 if (!sb->s_root)
709 return -ENOMEM;
710
711 ret = binderfs_binder_ctl_create(sb);
712 if (ret)
713 return ret;
714
715 name = binder_devices_param;
716 for (len = strcspn(name, ","); len > 0; len = strcspn(name, ",")) {
717 strscpy(device_info.name, name, len + 1);
718 ret = binderfs_binder_device_create(inode, NULL, &device_info);
719 if (ret)
720 return ret;
721 name += len;
722 if (*name == ',')
723 name++;
724 }
725
726 if (info->mount_opts.stats_mode == binderfs_stats_mode_global)
727 return init_binder_logs(sb);
728
729 return 0;
730}
731
732static int binderfs_fs_context_get_tree(struct fs_context *fc)
733{
734 return get_tree_nodev(fc, binderfs_fill_super);
735}
736
737static void binderfs_fs_context_free(struct fs_context *fc)
738{
739 struct binderfs_mount_opts *ctx = fc->fs_private;
740
741 kfree(ctx);
742}
743
744static const struct fs_context_operations binderfs_fs_context_ops = {
745 .free = binderfs_fs_context_free,
746 .get_tree = binderfs_fs_context_get_tree,
747 .parse_param = binderfs_fs_context_parse_param,
748 .reconfigure = binderfs_fs_context_reconfigure,
749};
750
751static int binderfs_init_fs_context(struct fs_context *fc)
752{
753 struct binderfs_mount_opts *ctx;
754
755 ctx = kzalloc(sizeof(struct binderfs_mount_opts), GFP_KERNEL);
756 if (!ctx)
757 return -ENOMEM;
758
759 ctx->max = BINDERFS_MAX_MINOR;
760 ctx->stats_mode = binderfs_stats_mode_unset;
761
762 fc->fs_private = ctx;
763 fc->ops = &binderfs_fs_context_ops;
764
765 return 0;
766}
767
768static struct file_system_type binder_fs_type = {
769 .name = "binder",
770 .init_fs_context = binderfs_init_fs_context,
771 .parameters = binderfs_fs_parameters,
772 .kill_sb = kill_litter_super,
773 .fs_flags = FS_USERNS_MOUNT,
774};
775
776int __init init_binderfs(void)
777{
778 int ret;
779 const char *name;
780 size_t len;
781
782 /* Verify that the default binderfs device names are valid. */
783 name = binder_devices_param;
784 for (len = strcspn(name, ","); len > 0; len = strcspn(name, ",")) {
785 if (len > BINDERFS_MAX_NAME)
786 return -E2BIG;
787 name += len;
788 if (*name == ',')
789 name++;
790 }
791
792 /* Allocate new major number for binderfs. */
793 ret = alloc_chrdev_region(&binderfs_dev, 0, BINDERFS_MAX_MINOR,
794 "binder");
795 if (ret)
796 return ret;
797
798 ret = register_filesystem(&binder_fs_type);
799 if (ret) {
800 unregister_chrdev_region(binderfs_dev, BINDERFS_MAX_MINOR);
801 return ret;
802 }
803
804 return ret;
805}