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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * devtmpfs - kernel-maintained tmpfs-based /dev
4 *
5 * Copyright (C) 2009, Kay Sievers <kay.sievers@vrfy.org>
6 *
7 * During bootup, before any driver core device is registered,
8 * devtmpfs, a tmpfs-based filesystem is created. Every driver-core
9 * device which requests a device node, will add a node in this
10 * filesystem.
11 * By default, all devices are named after the name of the device,
12 * owned by root and have a default mode of 0600. Subsystems can
13 * overwrite the default setting if needed.
14 */
15
16#include <linux/kernel.h>
17#include <linux/syscalls.h>
18#include <linux/mount.h>
19#include <linux/device.h>
20#include <linux/genhd.h>
21#include <linux/namei.h>
22#include <linux/fs.h>
23#include <linux/shmem_fs.h>
24#include <linux/ramfs.h>
25#include <linux/sched.h>
26#include <linux/slab.h>
27#include <linux/kthread.h>
28#include <linux/init_syscalls.h>
29#include <uapi/linux/mount.h>
30#include "base.h"
31
32static struct task_struct *thread;
33
34static int __initdata mount_dev = IS_ENABLED(CONFIG_DEVTMPFS_MOUNT);
35
36static DEFINE_SPINLOCK(req_lock);
37
38static struct req {
39 struct req *next;
40 struct completion done;
41 int err;
42 const char *name;
43 umode_t mode; /* 0 => delete */
44 kuid_t uid;
45 kgid_t gid;
46 struct device *dev;
47} *requests;
48
49static int __init mount_param(char *str)
50{
51 mount_dev = simple_strtoul(str, NULL, 0);
52 return 1;
53}
54__setup("devtmpfs.mount=", mount_param);
55
56static struct vfsmount *mnt;
57
58static struct dentry *public_dev_mount(struct file_system_type *fs_type, int flags,
59 const char *dev_name, void *data)
60{
61 struct super_block *s = mnt->mnt_sb;
62 atomic_inc(&s->s_active);
63 down_write(&s->s_umount);
64 return dget(s->s_root);
65}
66
67static struct file_system_type internal_fs_type = {
68 .name = "devtmpfs",
69#ifdef CONFIG_TMPFS
70 .init_fs_context = shmem_init_fs_context,
71 .parameters = shmem_fs_parameters,
72#else
73 .init_fs_context = ramfs_init_fs_context,
74 .parameters = ramfs_fs_parameters,
75#endif
76 .kill_sb = kill_litter_super,
77};
78
79static struct file_system_type dev_fs_type = {
80 .name = "devtmpfs",
81 .mount = public_dev_mount,
82};
83
84#ifdef CONFIG_BLOCK
85static inline int is_blockdev(struct device *dev)
86{
87 return dev->class == &block_class;
88}
89#else
90static inline int is_blockdev(struct device *dev) { return 0; }
91#endif
92
93static int devtmpfs_submit_req(struct req *req, const char *tmp)
94{
95 init_completion(&req->done);
96
97 spin_lock(&req_lock);
98 req->next = requests;
99 requests = req;
100 spin_unlock(&req_lock);
101
102 wake_up_process(thread);
103 wait_for_completion(&req->done);
104
105 kfree(tmp);
106
107 return req->err;
108}
109
110int devtmpfs_create_node(struct device *dev)
111{
112 const char *tmp = NULL;
113 struct req req;
114
115 if (!thread)
116 return 0;
117
118 req.mode = 0;
119 req.uid = GLOBAL_ROOT_UID;
120 req.gid = GLOBAL_ROOT_GID;
121 req.name = device_get_devnode(dev, &req.mode, &req.uid, &req.gid, &tmp);
122 if (!req.name)
123 return -ENOMEM;
124
125 if (req.mode == 0)
126 req.mode = 0600;
127 if (is_blockdev(dev))
128 req.mode |= S_IFBLK;
129 else
130 req.mode |= S_IFCHR;
131
132 req.dev = dev;
133
134 return devtmpfs_submit_req(&req, tmp);
135}
136
137int devtmpfs_delete_node(struct device *dev)
138{
139 const char *tmp = NULL;
140 struct req req;
141
142 if (!thread)
143 return 0;
144
145 req.name = device_get_devnode(dev, NULL, NULL, NULL, &tmp);
146 if (!req.name)
147 return -ENOMEM;
148
149 req.mode = 0;
150 req.dev = dev;
151
152 return devtmpfs_submit_req(&req, tmp);
153}
154
155static int dev_mkdir(const char *name, umode_t mode)
156{
157 struct dentry *dentry;
158 struct path path;
159 int err;
160
161 dentry = kern_path_create(AT_FDCWD, name, &path, LOOKUP_DIRECTORY);
162 if (IS_ERR(dentry))
163 return PTR_ERR(dentry);
164
165 err = vfs_mkdir(d_inode(path.dentry), dentry, mode);
166 if (!err)
167 /* mark as kernel-created inode */
168 d_inode(dentry)->i_private = &thread;
169 done_path_create(&path, dentry);
170 return err;
171}
172
173static int create_path(const char *nodepath)
174{
175 char *path;
176 char *s;
177 int err = 0;
178
179 /* parent directories do not exist, create them */
180 path = kstrdup(nodepath, GFP_KERNEL);
181 if (!path)
182 return -ENOMEM;
183
184 s = path;
185 for (;;) {
186 s = strchr(s, '/');
187 if (!s)
188 break;
189 s[0] = '\0';
190 err = dev_mkdir(path, 0755);
191 if (err && err != -EEXIST)
192 break;
193 s[0] = '/';
194 s++;
195 }
196 kfree(path);
197 return err;
198}
199
200static int handle_create(const char *nodename, umode_t mode, kuid_t uid,
201 kgid_t gid, struct device *dev)
202{
203 struct dentry *dentry;
204 struct path path;
205 int err;
206
207 dentry = kern_path_create(AT_FDCWD, nodename, &path, 0);
208 if (dentry == ERR_PTR(-ENOENT)) {
209 create_path(nodename);
210 dentry = kern_path_create(AT_FDCWD, nodename, &path, 0);
211 }
212 if (IS_ERR(dentry))
213 return PTR_ERR(dentry);
214
215 err = vfs_mknod(d_inode(path.dentry), dentry, mode, dev->devt);
216 if (!err) {
217 struct iattr newattrs;
218
219 newattrs.ia_mode = mode;
220 newattrs.ia_uid = uid;
221 newattrs.ia_gid = gid;
222 newattrs.ia_valid = ATTR_MODE|ATTR_UID|ATTR_GID;
223 inode_lock(d_inode(dentry));
224 notify_change(dentry, &newattrs, NULL);
225 inode_unlock(d_inode(dentry));
226
227 /* mark as kernel-created inode */
228 d_inode(dentry)->i_private = &thread;
229 }
230 done_path_create(&path, dentry);
231 return err;
232}
233
234static int dev_rmdir(const char *name)
235{
236 struct path parent;
237 struct dentry *dentry;
238 int err;
239
240 dentry = kern_path_locked(name, &parent);
241 if (IS_ERR(dentry))
242 return PTR_ERR(dentry);
243 if (d_really_is_positive(dentry)) {
244 if (d_inode(dentry)->i_private == &thread)
245 err = vfs_rmdir(d_inode(parent.dentry), dentry);
246 else
247 err = -EPERM;
248 } else {
249 err = -ENOENT;
250 }
251 dput(dentry);
252 inode_unlock(d_inode(parent.dentry));
253 path_put(&parent);
254 return err;
255}
256
257static int delete_path(const char *nodepath)
258{
259 char *path;
260 int err = 0;
261
262 path = kstrdup(nodepath, GFP_KERNEL);
263 if (!path)
264 return -ENOMEM;
265
266 for (;;) {
267 char *base;
268
269 base = strrchr(path, '/');
270 if (!base)
271 break;
272 base[0] = '\0';
273 err = dev_rmdir(path);
274 if (err)
275 break;
276 }
277
278 kfree(path);
279 return err;
280}
281
282static int dev_mynode(struct device *dev, struct inode *inode, struct kstat *stat)
283{
284 /* did we create it */
285 if (inode->i_private != &thread)
286 return 0;
287
288 /* does the dev_t match */
289 if (is_blockdev(dev)) {
290 if (!S_ISBLK(stat->mode))
291 return 0;
292 } else {
293 if (!S_ISCHR(stat->mode))
294 return 0;
295 }
296 if (stat->rdev != dev->devt)
297 return 0;
298
299 /* ours */
300 return 1;
301}
302
303static int handle_remove(const char *nodename, struct device *dev)
304{
305 struct path parent;
306 struct dentry *dentry;
307 int deleted = 0;
308 int err;
309
310 dentry = kern_path_locked(nodename, &parent);
311 if (IS_ERR(dentry))
312 return PTR_ERR(dentry);
313
314 if (d_really_is_positive(dentry)) {
315 struct kstat stat;
316 struct path p = {.mnt = parent.mnt, .dentry = dentry};
317 err = vfs_getattr(&p, &stat, STATX_TYPE | STATX_MODE,
318 AT_STATX_SYNC_AS_STAT);
319 if (!err && dev_mynode(dev, d_inode(dentry), &stat)) {
320 struct iattr newattrs;
321 /*
322 * before unlinking this node, reset permissions
323 * of possible references like hardlinks
324 */
325 newattrs.ia_uid = GLOBAL_ROOT_UID;
326 newattrs.ia_gid = GLOBAL_ROOT_GID;
327 newattrs.ia_mode = stat.mode & ~0777;
328 newattrs.ia_valid =
329 ATTR_UID|ATTR_GID|ATTR_MODE;
330 inode_lock(d_inode(dentry));
331 notify_change(dentry, &newattrs, NULL);
332 inode_unlock(d_inode(dentry));
333 err = vfs_unlink(d_inode(parent.dentry), dentry, NULL);
334 if (!err || err == -ENOENT)
335 deleted = 1;
336 }
337 } else {
338 err = -ENOENT;
339 }
340 dput(dentry);
341 inode_unlock(d_inode(parent.dentry));
342
343 path_put(&parent);
344 if (deleted && strchr(nodename, '/'))
345 delete_path(nodename);
346 return err;
347}
348
349/*
350 * If configured, or requested by the commandline, devtmpfs will be
351 * auto-mounted after the kernel mounted the root filesystem.
352 */
353int __init devtmpfs_mount(void)
354{
355 int err;
356
357 if (!mount_dev)
358 return 0;
359
360 if (!thread)
361 return 0;
362
363 err = init_mount("devtmpfs", "dev", "devtmpfs", MS_SILENT, NULL);
364 if (err)
365 printk(KERN_INFO "devtmpfs: error mounting %i\n", err);
366 else
367 printk(KERN_INFO "devtmpfs: mounted\n");
368 return err;
369}
370
371static DECLARE_COMPLETION(setup_done);
372
373static int handle(const char *name, umode_t mode, kuid_t uid, kgid_t gid,
374 struct device *dev)
375{
376 if (mode)
377 return handle_create(name, mode, uid, gid, dev);
378 else
379 return handle_remove(name, dev);
380}
381
382static void __noreturn devtmpfs_work_loop(void)
383{
384 while (1) {
385 spin_lock(&req_lock);
386 while (requests) {
387 struct req *req = requests;
388 requests = NULL;
389 spin_unlock(&req_lock);
390 while (req) {
391 struct req *next = req->next;
392 req->err = handle(req->name, req->mode,
393 req->uid, req->gid, req->dev);
394 complete(&req->done);
395 req = next;
396 }
397 spin_lock(&req_lock);
398 }
399 __set_current_state(TASK_INTERRUPTIBLE);
400 spin_unlock(&req_lock);
401 schedule();
402 }
403}
404
405static int __init devtmpfs_setup(void *p)
406{
407 int err;
408
409 err = ksys_unshare(CLONE_NEWNS);
410 if (err)
411 goto out;
412 err = init_mount("devtmpfs", "/", "devtmpfs", MS_SILENT, NULL);
413 if (err)
414 goto out;
415 init_chdir("/.."); /* will traverse into overmounted root */
416 init_chroot(".");
417out:
418 *(int *)p = err;
419 complete(&setup_done);
420 return err;
421}
422
423/*
424 * The __ref is because devtmpfs_setup needs to be __init for the routines it
425 * calls. That call is done while devtmpfs_init, which is marked __init,
426 * synchronously waits for it to complete.
427 */
428static int __ref devtmpfsd(void *p)
429{
430 int err = devtmpfs_setup(p);
431
432 if (err)
433 return err;
434 devtmpfs_work_loop();
435 return 0;
436}
437
438/*
439 * Create devtmpfs instance, driver-core devices will add their device
440 * nodes here.
441 */
442int __init devtmpfs_init(void)
443{
444 char opts[] = "mode=0755";
445 int err;
446
447 mnt = vfs_kern_mount(&internal_fs_type, 0, "devtmpfs", opts);
448 if (IS_ERR(mnt)) {
449 printk(KERN_ERR "devtmpfs: unable to create devtmpfs %ld\n",
450 PTR_ERR(mnt));
451 return PTR_ERR(mnt);
452 }
453 err = register_filesystem(&dev_fs_type);
454 if (err) {
455 printk(KERN_ERR "devtmpfs: unable to register devtmpfs "
456 "type %i\n", err);
457 return err;
458 }
459
460 thread = kthread_run(devtmpfsd, &err, "kdevtmpfs");
461 if (!IS_ERR(thread)) {
462 wait_for_completion(&setup_done);
463 } else {
464 err = PTR_ERR(thread);
465 thread = NULL;
466 }
467
468 if (err) {
469 printk(KERN_ERR "devtmpfs: unable to create devtmpfs %i\n", err);
470 unregister_filesystem(&dev_fs_type);
471 return err;
472 }
473
474 printk(KERN_INFO "devtmpfs: initialized\n");
475 return 0;
476}
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * devtmpfs - kernel-maintained tmpfs-based /dev
4 *
5 * Copyright (C) 2009, Kay Sievers <kay.sievers@vrfy.org>
6 *
7 * During bootup, before any driver core device is registered,
8 * devtmpfs, a tmpfs-based filesystem is created. Every driver-core
9 * device which requests a device node, will add a node in this
10 * filesystem.
11 * By default, all devices are named after the name of the device,
12 * owned by root and have a default mode of 0600. Subsystems can
13 * overwrite the default setting if needed.
14 */
15
16#include <linux/kernel.h>
17#include <linux/syscalls.h>
18#include <linux/mount.h>
19#include <linux/device.h>
20#include <linux/genhd.h>
21#include <linux/namei.h>
22#include <linux/fs.h>
23#include <linux/shmem_fs.h>
24#include <linux/ramfs.h>
25#include <linux/sched.h>
26#include <linux/slab.h>
27#include <linux/kthread.h>
28#include <uapi/linux/mount.h>
29#include "base.h"
30
31static struct task_struct *thread;
32
33#if defined CONFIG_DEVTMPFS_MOUNT
34static int mount_dev = 1;
35#else
36static int mount_dev;
37#endif
38
39static DEFINE_SPINLOCK(req_lock);
40
41static struct req {
42 struct req *next;
43 struct completion done;
44 int err;
45 const char *name;
46 umode_t mode; /* 0 => delete */
47 kuid_t uid;
48 kgid_t gid;
49 struct device *dev;
50} *requests;
51
52static int __init mount_param(char *str)
53{
54 mount_dev = simple_strtoul(str, NULL, 0);
55 return 1;
56}
57__setup("devtmpfs.mount=", mount_param);
58
59static struct vfsmount *mnt;
60
61static struct dentry *public_dev_mount(struct file_system_type *fs_type, int flags,
62 const char *dev_name, void *data)
63{
64 struct super_block *s = mnt->mnt_sb;
65 atomic_inc(&s->s_active);
66 down_write(&s->s_umount);
67 return dget(s->s_root);
68}
69
70static struct file_system_type internal_fs_type = {
71 .name = "devtmpfs",
72#ifdef CONFIG_TMPFS
73 .init_fs_context = shmem_init_fs_context,
74 .parameters = &shmem_fs_parameters,
75#else
76 .init_fs_context = ramfs_init_fs_context,
77 .parameters = &ramfs_fs_parameters,
78#endif
79 .kill_sb = kill_litter_super,
80};
81
82static struct file_system_type dev_fs_type = {
83 .name = "devtmpfs",
84 .mount = public_dev_mount,
85};
86
87#ifdef CONFIG_BLOCK
88static inline int is_blockdev(struct device *dev)
89{
90 return dev->class == &block_class;
91}
92#else
93static inline int is_blockdev(struct device *dev) { return 0; }
94#endif
95
96int devtmpfs_create_node(struct device *dev)
97{
98 const char *tmp = NULL;
99 struct req req;
100
101 if (!thread)
102 return 0;
103
104 req.mode = 0;
105 req.uid = GLOBAL_ROOT_UID;
106 req.gid = GLOBAL_ROOT_GID;
107 req.name = device_get_devnode(dev, &req.mode, &req.uid, &req.gid, &tmp);
108 if (!req.name)
109 return -ENOMEM;
110
111 if (req.mode == 0)
112 req.mode = 0600;
113 if (is_blockdev(dev))
114 req.mode |= S_IFBLK;
115 else
116 req.mode |= S_IFCHR;
117
118 req.dev = dev;
119
120 init_completion(&req.done);
121
122 spin_lock(&req_lock);
123 req.next = requests;
124 requests = &req;
125 spin_unlock(&req_lock);
126
127 wake_up_process(thread);
128 wait_for_completion(&req.done);
129
130 kfree(tmp);
131
132 return req.err;
133}
134
135int devtmpfs_delete_node(struct device *dev)
136{
137 const char *tmp = NULL;
138 struct req req;
139
140 if (!thread)
141 return 0;
142
143 req.name = device_get_devnode(dev, NULL, NULL, NULL, &tmp);
144 if (!req.name)
145 return -ENOMEM;
146
147 req.mode = 0;
148 req.dev = dev;
149
150 init_completion(&req.done);
151
152 spin_lock(&req_lock);
153 req.next = requests;
154 requests = &req;
155 spin_unlock(&req_lock);
156
157 wake_up_process(thread);
158 wait_for_completion(&req.done);
159
160 kfree(tmp);
161 return req.err;
162}
163
164static int dev_mkdir(const char *name, umode_t mode)
165{
166 struct dentry *dentry;
167 struct path path;
168 int err;
169
170 dentry = kern_path_create(AT_FDCWD, name, &path, LOOKUP_DIRECTORY);
171 if (IS_ERR(dentry))
172 return PTR_ERR(dentry);
173
174 err = vfs_mkdir(d_inode(path.dentry), dentry, mode);
175 if (!err)
176 /* mark as kernel-created inode */
177 d_inode(dentry)->i_private = &thread;
178 done_path_create(&path, dentry);
179 return err;
180}
181
182static int create_path(const char *nodepath)
183{
184 char *path;
185 char *s;
186 int err = 0;
187
188 /* parent directories do not exist, create them */
189 path = kstrdup(nodepath, GFP_KERNEL);
190 if (!path)
191 return -ENOMEM;
192
193 s = path;
194 for (;;) {
195 s = strchr(s, '/');
196 if (!s)
197 break;
198 s[0] = '\0';
199 err = dev_mkdir(path, 0755);
200 if (err && err != -EEXIST)
201 break;
202 s[0] = '/';
203 s++;
204 }
205 kfree(path);
206 return err;
207}
208
209static int handle_create(const char *nodename, umode_t mode, kuid_t uid,
210 kgid_t gid, struct device *dev)
211{
212 struct dentry *dentry;
213 struct path path;
214 int err;
215
216 dentry = kern_path_create(AT_FDCWD, nodename, &path, 0);
217 if (dentry == ERR_PTR(-ENOENT)) {
218 create_path(nodename);
219 dentry = kern_path_create(AT_FDCWD, nodename, &path, 0);
220 }
221 if (IS_ERR(dentry))
222 return PTR_ERR(dentry);
223
224 err = vfs_mknod(d_inode(path.dentry), dentry, mode, dev->devt);
225 if (!err) {
226 struct iattr newattrs;
227
228 newattrs.ia_mode = mode;
229 newattrs.ia_uid = uid;
230 newattrs.ia_gid = gid;
231 newattrs.ia_valid = ATTR_MODE|ATTR_UID|ATTR_GID;
232 inode_lock(d_inode(dentry));
233 notify_change(dentry, &newattrs, NULL);
234 inode_unlock(d_inode(dentry));
235
236 /* mark as kernel-created inode */
237 d_inode(dentry)->i_private = &thread;
238 }
239 done_path_create(&path, dentry);
240 return err;
241}
242
243static int dev_rmdir(const char *name)
244{
245 struct path parent;
246 struct dentry *dentry;
247 int err;
248
249 dentry = kern_path_locked(name, &parent);
250 if (IS_ERR(dentry))
251 return PTR_ERR(dentry);
252 if (d_really_is_positive(dentry)) {
253 if (d_inode(dentry)->i_private == &thread)
254 err = vfs_rmdir(d_inode(parent.dentry), dentry);
255 else
256 err = -EPERM;
257 } else {
258 err = -ENOENT;
259 }
260 dput(dentry);
261 inode_unlock(d_inode(parent.dentry));
262 path_put(&parent);
263 return err;
264}
265
266static int delete_path(const char *nodepath)
267{
268 char *path;
269 int err = 0;
270
271 path = kstrdup(nodepath, GFP_KERNEL);
272 if (!path)
273 return -ENOMEM;
274
275 for (;;) {
276 char *base;
277
278 base = strrchr(path, '/');
279 if (!base)
280 break;
281 base[0] = '\0';
282 err = dev_rmdir(path);
283 if (err)
284 break;
285 }
286
287 kfree(path);
288 return err;
289}
290
291static int dev_mynode(struct device *dev, struct inode *inode, struct kstat *stat)
292{
293 /* did we create it */
294 if (inode->i_private != &thread)
295 return 0;
296
297 /* does the dev_t match */
298 if (is_blockdev(dev)) {
299 if (!S_ISBLK(stat->mode))
300 return 0;
301 } else {
302 if (!S_ISCHR(stat->mode))
303 return 0;
304 }
305 if (stat->rdev != dev->devt)
306 return 0;
307
308 /* ours */
309 return 1;
310}
311
312static int handle_remove(const char *nodename, struct device *dev)
313{
314 struct path parent;
315 struct dentry *dentry;
316 int deleted = 0;
317 int err;
318
319 dentry = kern_path_locked(nodename, &parent);
320 if (IS_ERR(dentry))
321 return PTR_ERR(dentry);
322
323 if (d_really_is_positive(dentry)) {
324 struct kstat stat;
325 struct path p = {.mnt = parent.mnt, .dentry = dentry};
326 err = vfs_getattr(&p, &stat, STATX_TYPE | STATX_MODE,
327 AT_STATX_SYNC_AS_STAT);
328 if (!err && dev_mynode(dev, d_inode(dentry), &stat)) {
329 struct iattr newattrs;
330 /*
331 * before unlinking this node, reset permissions
332 * of possible references like hardlinks
333 */
334 newattrs.ia_uid = GLOBAL_ROOT_UID;
335 newattrs.ia_gid = GLOBAL_ROOT_GID;
336 newattrs.ia_mode = stat.mode & ~0777;
337 newattrs.ia_valid =
338 ATTR_UID|ATTR_GID|ATTR_MODE;
339 inode_lock(d_inode(dentry));
340 notify_change(dentry, &newattrs, NULL);
341 inode_unlock(d_inode(dentry));
342 err = vfs_unlink(d_inode(parent.dentry), dentry, NULL);
343 if (!err || err == -ENOENT)
344 deleted = 1;
345 }
346 } else {
347 err = -ENOENT;
348 }
349 dput(dentry);
350 inode_unlock(d_inode(parent.dentry));
351
352 path_put(&parent);
353 if (deleted && strchr(nodename, '/'))
354 delete_path(nodename);
355 return err;
356}
357
358/*
359 * If configured, or requested by the commandline, devtmpfs will be
360 * auto-mounted after the kernel mounted the root filesystem.
361 */
362int devtmpfs_mount(const char *mntdir)
363{
364 int err;
365
366 if (!mount_dev)
367 return 0;
368
369 if (!thread)
370 return 0;
371
372 err = ksys_mount("devtmpfs", mntdir, "devtmpfs", MS_SILENT, NULL);
373 if (err)
374 printk(KERN_INFO "devtmpfs: error mounting %i\n", err);
375 else
376 printk(KERN_INFO "devtmpfs: mounted\n");
377 return err;
378}
379
380static DECLARE_COMPLETION(setup_done);
381
382static int handle(const char *name, umode_t mode, kuid_t uid, kgid_t gid,
383 struct device *dev)
384{
385 if (mode)
386 return handle_create(name, mode, uid, gid, dev);
387 else
388 return handle_remove(name, dev);
389}
390
391static int devtmpfsd(void *p)
392{
393 int *err = p;
394 *err = ksys_unshare(CLONE_NEWNS);
395 if (*err)
396 goto out;
397 *err = ksys_mount("devtmpfs", "/", "devtmpfs", MS_SILENT, NULL);
398 if (*err)
399 goto out;
400 ksys_chdir("/.."); /* will traverse into overmounted root */
401 ksys_chroot(".");
402 complete(&setup_done);
403 while (1) {
404 spin_lock(&req_lock);
405 while (requests) {
406 struct req *req = requests;
407 requests = NULL;
408 spin_unlock(&req_lock);
409 while (req) {
410 struct req *next = req->next;
411 req->err = handle(req->name, req->mode,
412 req->uid, req->gid, req->dev);
413 complete(&req->done);
414 req = next;
415 }
416 spin_lock(&req_lock);
417 }
418 __set_current_state(TASK_INTERRUPTIBLE);
419 spin_unlock(&req_lock);
420 schedule();
421 }
422 return 0;
423out:
424 complete(&setup_done);
425 return *err;
426}
427
428/*
429 * Create devtmpfs instance, driver-core devices will add their device
430 * nodes here.
431 */
432int __init devtmpfs_init(void)
433{
434 char opts[] = "mode=0755";
435 int err;
436
437 mnt = vfs_kern_mount(&internal_fs_type, 0, "devtmpfs", opts);
438 if (IS_ERR(mnt)) {
439 printk(KERN_ERR "devtmpfs: unable to create devtmpfs %ld\n",
440 PTR_ERR(mnt));
441 return PTR_ERR(mnt);
442 }
443 err = register_filesystem(&dev_fs_type);
444 if (err) {
445 printk(KERN_ERR "devtmpfs: unable to register devtmpfs "
446 "type %i\n", err);
447 return err;
448 }
449
450 thread = kthread_run(devtmpfsd, &err, "kdevtmpfs");
451 if (!IS_ERR(thread)) {
452 wait_for_completion(&setup_done);
453 } else {
454 err = PTR_ERR(thread);
455 thread = NULL;
456 }
457
458 if (err) {
459 printk(KERN_ERR "devtmpfs: unable to create devtmpfs %i\n", err);
460 unregister_filesystem(&dev_fs_type);
461 return err;
462 }
463
464 printk(KERN_INFO "devtmpfs: initialized\n");
465 return 0;
466}