Loading...
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * fs/sysfs/dir.c - sysfs core and dir operation implementation
4 *
5 * Copyright (c) 2001-3 Patrick Mochel
6 * Copyright (c) 2007 SUSE Linux Products GmbH
7 * Copyright (c) 2007 Tejun Heo <teheo@suse.de>
8 *
9 * Please see Documentation/filesystems/sysfs.rst for more information.
10 */
11
12#define pr_fmt(fmt) "sysfs: " fmt
13
14#include <linux/fs.h>
15#include <linux/kobject.h>
16#include <linux/slab.h>
17#include "sysfs.h"
18
19DEFINE_SPINLOCK(sysfs_symlink_target_lock);
20
21void sysfs_warn_dup(struct kernfs_node *parent, const char *name)
22{
23 char *buf;
24
25 buf = kzalloc(PATH_MAX, GFP_KERNEL);
26 if (buf)
27 kernfs_path(parent, buf, PATH_MAX);
28
29 pr_warn("cannot create duplicate filename '%s/%s'\n", buf, name);
30 dump_stack();
31
32 kfree(buf);
33}
34
35/**
36 * sysfs_create_dir_ns - create a directory for an object with a namespace tag
37 * @kobj: object we're creating directory for
38 * @ns: the namespace tag to use
39 */
40int sysfs_create_dir_ns(struct kobject *kobj, const void *ns)
41{
42 struct kernfs_node *parent, *kn;
43 kuid_t uid;
44 kgid_t gid;
45
46 if (WARN_ON(!kobj))
47 return -EINVAL;
48
49 if (kobj->parent)
50 parent = kobj->parent->sd;
51 else
52 parent = sysfs_root_kn;
53
54 if (!parent)
55 return -ENOENT;
56
57 kobject_get_ownership(kobj, &uid, &gid);
58
59 kn = kernfs_create_dir_ns(parent, kobject_name(kobj), 0755, uid, gid,
60 kobj, ns);
61 if (IS_ERR(kn)) {
62 if (PTR_ERR(kn) == -EEXIST)
63 sysfs_warn_dup(parent, kobject_name(kobj));
64 return PTR_ERR(kn);
65 }
66
67 kobj->sd = kn;
68 return 0;
69}
70
71/**
72 * sysfs_remove_dir - remove an object's directory.
73 * @kobj: object.
74 *
75 * The only thing special about this is that we remove any files in
76 * the directory before we remove the directory, and we've inlined
77 * what used to be sysfs_rmdir() below, instead of calling separately.
78 */
79void sysfs_remove_dir(struct kobject *kobj)
80{
81 struct kernfs_node *kn = kobj->sd;
82
83 /*
84 * In general, kobject owner is responsible for ensuring removal
85 * doesn't race with other operations and sysfs doesn't provide any
86 * protection; however, when @kobj is used as a symlink target, the
87 * symlinking entity usually doesn't own @kobj and thus has no
88 * control over removal. @kobj->sd may be removed anytime
89 * and symlink code may end up dereferencing an already freed node.
90 *
91 * sysfs_symlink_target_lock synchronizes @kobj->sd
92 * disassociation against symlink operations so that symlink code
93 * can safely dereference @kobj->sd.
94 */
95 spin_lock(&sysfs_symlink_target_lock);
96 kobj->sd = NULL;
97 spin_unlock(&sysfs_symlink_target_lock);
98
99 if (kn) {
100 WARN_ON_ONCE(kernfs_type(kn) != KERNFS_DIR);
101 kernfs_remove(kn);
102 }
103}
104
105int sysfs_rename_dir_ns(struct kobject *kobj, const char *new_name,
106 const void *new_ns)
107{
108 struct kernfs_node *parent;
109 int ret;
110
111 parent = kernfs_get_parent(kobj->sd);
112 ret = kernfs_rename_ns(kobj->sd, parent, new_name, new_ns);
113 kernfs_put(parent);
114 return ret;
115}
116
117int sysfs_move_dir_ns(struct kobject *kobj, struct kobject *new_parent_kobj,
118 const void *new_ns)
119{
120 struct kernfs_node *kn = kobj->sd;
121 struct kernfs_node *new_parent;
122
123 new_parent = new_parent_kobj && new_parent_kobj->sd ?
124 new_parent_kobj->sd : sysfs_root_kn;
125
126 return kernfs_rename_ns(kn, new_parent, kn->name, new_ns);
127}
128
129/**
130 * sysfs_create_mount_point - create an always empty directory
131 * @parent_kobj: kobject that will contain this always empty directory
132 * @name: The name of the always empty directory to add
133 */
134int sysfs_create_mount_point(struct kobject *parent_kobj, const char *name)
135{
136 struct kernfs_node *kn, *parent = parent_kobj->sd;
137
138 kn = kernfs_create_empty_dir(parent, name);
139 if (IS_ERR(kn)) {
140 if (PTR_ERR(kn) == -EEXIST)
141 sysfs_warn_dup(parent, name);
142 return PTR_ERR(kn);
143 }
144
145 return 0;
146}
147EXPORT_SYMBOL_GPL(sysfs_create_mount_point);
148
149/**
150 * sysfs_remove_mount_point - remove an always empty directory.
151 * @parent_kobj: kobject that will contain this always empty directory
152 * @name: The name of the always empty directory to remove
153 *
154 */
155void sysfs_remove_mount_point(struct kobject *parent_kobj, const char *name)
156{
157 struct kernfs_node *parent = parent_kobj->sd;
158
159 kernfs_remove_by_name_ns(parent, name, NULL);
160}
161EXPORT_SYMBOL_GPL(sysfs_remove_mount_point);
1/*
2 * fs/sysfs/dir.c - sysfs core and dir operation implementation
3 *
4 * Copyright (c) 2001-3 Patrick Mochel
5 * Copyright (c) 2007 SUSE Linux Products GmbH
6 * Copyright (c) 2007 Tejun Heo <teheo@suse.de>
7 *
8 * This file is released under the GPLv2.
9 *
10 * Please see Documentation/filesystems/sysfs.txt for more information.
11 */
12
13#undef DEBUG
14
15#include <linux/fs.h>
16#include <linux/mount.h>
17#include <linux/module.h>
18#include <linux/kobject.h>
19#include <linux/namei.h>
20#include <linux/idr.h>
21#include <linux/completion.h>
22#include <linux/mutex.h>
23#include <linux/slab.h>
24#include <linux/security.h>
25#include "sysfs.h"
26
27DEFINE_MUTEX(sysfs_mutex);
28DEFINE_SPINLOCK(sysfs_assoc_lock);
29
30static DEFINE_SPINLOCK(sysfs_ino_lock);
31static DEFINE_IDA(sysfs_ino_ida);
32
33/**
34 * sysfs_link_sibling - link sysfs_dirent into sibling list
35 * @sd: sysfs_dirent of interest
36 *
37 * Link @sd into its sibling list which starts from
38 * sd->s_parent->s_dir.children.
39 *
40 * Locking:
41 * mutex_lock(sysfs_mutex)
42 */
43static void sysfs_link_sibling(struct sysfs_dirent *sd)
44{
45 struct sysfs_dirent *parent_sd = sd->s_parent;
46 struct sysfs_dirent **pos;
47
48 BUG_ON(sd->s_sibling);
49
50 /* Store directory entries in order by ino. This allows
51 * readdir to properly restart without having to add a
52 * cursor into the s_dir.children list.
53 */
54 for (pos = &parent_sd->s_dir.children; *pos; pos = &(*pos)->s_sibling) {
55 if (sd->s_ino < (*pos)->s_ino)
56 break;
57 }
58 sd->s_sibling = *pos;
59 *pos = sd;
60}
61
62/**
63 * sysfs_unlink_sibling - unlink sysfs_dirent from sibling list
64 * @sd: sysfs_dirent of interest
65 *
66 * Unlink @sd from its sibling list which starts from
67 * sd->s_parent->s_dir.children.
68 *
69 * Locking:
70 * mutex_lock(sysfs_mutex)
71 */
72static void sysfs_unlink_sibling(struct sysfs_dirent *sd)
73{
74 struct sysfs_dirent **pos;
75
76 for (pos = &sd->s_parent->s_dir.children; *pos;
77 pos = &(*pos)->s_sibling) {
78 if (*pos == sd) {
79 *pos = sd->s_sibling;
80 sd->s_sibling = NULL;
81 break;
82 }
83 }
84}
85
86/**
87 * sysfs_get_active - get an active reference to sysfs_dirent
88 * @sd: sysfs_dirent to get an active reference to
89 *
90 * Get an active reference of @sd. This function is noop if @sd
91 * is NULL.
92 *
93 * RETURNS:
94 * Pointer to @sd on success, NULL on failure.
95 */
96struct sysfs_dirent *sysfs_get_active(struct sysfs_dirent *sd)
97{
98 if (unlikely(!sd))
99 return NULL;
100
101 while (1) {
102 int v, t;
103
104 v = atomic_read(&sd->s_active);
105 if (unlikely(v < 0))
106 return NULL;
107
108 t = atomic_cmpxchg(&sd->s_active, v, v + 1);
109 if (likely(t == v)) {
110 rwsem_acquire_read(&sd->dep_map, 0, 1, _RET_IP_);
111 return sd;
112 }
113 if (t < 0)
114 return NULL;
115
116 cpu_relax();
117 }
118}
119
120/**
121 * sysfs_put_active - put an active reference to sysfs_dirent
122 * @sd: sysfs_dirent to put an active reference to
123 *
124 * Put an active reference to @sd. This function is noop if @sd
125 * is NULL.
126 */
127void sysfs_put_active(struct sysfs_dirent *sd)
128{
129 struct completion *cmpl;
130 int v;
131
132 if (unlikely(!sd))
133 return;
134
135 rwsem_release(&sd->dep_map, 1, _RET_IP_);
136 v = atomic_dec_return(&sd->s_active);
137 if (likely(v != SD_DEACTIVATED_BIAS))
138 return;
139
140 /* atomic_dec_return() is a mb(), we'll always see the updated
141 * sd->s_sibling.
142 */
143 cmpl = (void *)sd->s_sibling;
144 complete(cmpl);
145}
146
147/**
148 * sysfs_deactivate - deactivate sysfs_dirent
149 * @sd: sysfs_dirent to deactivate
150 *
151 * Deny new active references and drain existing ones.
152 */
153static void sysfs_deactivate(struct sysfs_dirent *sd)
154{
155 DECLARE_COMPLETION_ONSTACK(wait);
156 int v;
157
158 BUG_ON(sd->s_sibling || !(sd->s_flags & SYSFS_FLAG_REMOVED));
159
160 if (!(sysfs_type(sd) & SYSFS_ACTIVE_REF))
161 return;
162
163 sd->s_sibling = (void *)&wait;
164
165 rwsem_acquire(&sd->dep_map, 0, 0, _RET_IP_);
166 /* atomic_add_return() is a mb(), put_active() will always see
167 * the updated sd->s_sibling.
168 */
169 v = atomic_add_return(SD_DEACTIVATED_BIAS, &sd->s_active);
170
171 if (v != SD_DEACTIVATED_BIAS) {
172 lock_contended(&sd->dep_map, _RET_IP_);
173 wait_for_completion(&wait);
174 }
175
176 sd->s_sibling = NULL;
177
178 lock_acquired(&sd->dep_map, _RET_IP_);
179 rwsem_release(&sd->dep_map, 1, _RET_IP_);
180}
181
182static int sysfs_alloc_ino(ino_t *pino)
183{
184 int ino, rc;
185
186 retry:
187 spin_lock(&sysfs_ino_lock);
188 rc = ida_get_new_above(&sysfs_ino_ida, 2, &ino);
189 spin_unlock(&sysfs_ino_lock);
190
191 if (rc == -EAGAIN) {
192 if (ida_pre_get(&sysfs_ino_ida, GFP_KERNEL))
193 goto retry;
194 rc = -ENOMEM;
195 }
196
197 *pino = ino;
198 return rc;
199}
200
201static void sysfs_free_ino(ino_t ino)
202{
203 spin_lock(&sysfs_ino_lock);
204 ida_remove(&sysfs_ino_ida, ino);
205 spin_unlock(&sysfs_ino_lock);
206}
207
208void release_sysfs_dirent(struct sysfs_dirent * sd)
209{
210 struct sysfs_dirent *parent_sd;
211
212 repeat:
213 /* Moving/renaming is always done while holding reference.
214 * sd->s_parent won't change beneath us.
215 */
216 parent_sd = sd->s_parent;
217
218 if (sysfs_type(sd) == SYSFS_KOBJ_LINK)
219 sysfs_put(sd->s_symlink.target_sd);
220 if (sysfs_type(sd) & SYSFS_COPY_NAME)
221 kfree(sd->s_name);
222 if (sd->s_iattr && sd->s_iattr->ia_secdata)
223 security_release_secctx(sd->s_iattr->ia_secdata,
224 sd->s_iattr->ia_secdata_len);
225 kfree(sd->s_iattr);
226 sysfs_free_ino(sd->s_ino);
227 kmem_cache_free(sysfs_dir_cachep, sd);
228
229 sd = parent_sd;
230 if (sd && atomic_dec_and_test(&sd->s_count))
231 goto repeat;
232}
233
234static int sysfs_dentry_delete(const struct dentry *dentry)
235{
236 struct sysfs_dirent *sd = dentry->d_fsdata;
237 return !!(sd->s_flags & SYSFS_FLAG_REMOVED);
238}
239
240static int sysfs_dentry_revalidate(struct dentry *dentry, struct nameidata *nd)
241{
242 struct sysfs_dirent *sd;
243 int is_dir;
244
245 if (nd->flags & LOOKUP_RCU)
246 return -ECHILD;
247
248 sd = dentry->d_fsdata;
249 mutex_lock(&sysfs_mutex);
250
251 /* The sysfs dirent has been deleted */
252 if (sd->s_flags & SYSFS_FLAG_REMOVED)
253 goto out_bad;
254
255 /* The sysfs dirent has been moved? */
256 if (dentry->d_parent->d_fsdata != sd->s_parent)
257 goto out_bad;
258
259 /* The sysfs dirent has been renamed */
260 if (strcmp(dentry->d_name.name, sd->s_name) != 0)
261 goto out_bad;
262
263 mutex_unlock(&sysfs_mutex);
264out_valid:
265 return 1;
266out_bad:
267 /* Remove the dentry from the dcache hashes.
268 * If this is a deleted dentry we use d_drop instead of d_delete
269 * so sysfs doesn't need to cope with negative dentries.
270 *
271 * If this is a dentry that has simply been renamed we
272 * use d_drop to remove it from the dcache lookup on its
273 * old parent. If this dentry persists later when a lookup
274 * is performed at its new name the dentry will be readded
275 * to the dcache hashes.
276 */
277 is_dir = (sysfs_type(sd) == SYSFS_DIR);
278 mutex_unlock(&sysfs_mutex);
279 if (is_dir) {
280 /* If we have submounts we must allow the vfs caches
281 * to lie about the state of the filesystem to prevent
282 * leaks and other nasty things.
283 */
284 if (have_submounts(dentry))
285 goto out_valid;
286 shrink_dcache_parent(dentry);
287 }
288 d_drop(dentry);
289 return 0;
290}
291
292static void sysfs_dentry_iput(struct dentry *dentry, struct inode *inode)
293{
294 struct sysfs_dirent * sd = dentry->d_fsdata;
295
296 sysfs_put(sd);
297 iput(inode);
298}
299
300static const struct dentry_operations sysfs_dentry_ops = {
301 .d_revalidate = sysfs_dentry_revalidate,
302 .d_delete = sysfs_dentry_delete,
303 .d_iput = sysfs_dentry_iput,
304};
305
306struct sysfs_dirent *sysfs_new_dirent(const char *name, umode_t mode, int type)
307{
308 char *dup_name = NULL;
309 struct sysfs_dirent *sd;
310
311 if (type & SYSFS_COPY_NAME) {
312 name = dup_name = kstrdup(name, GFP_KERNEL);
313 if (!name)
314 return NULL;
315 }
316
317 sd = kmem_cache_zalloc(sysfs_dir_cachep, GFP_KERNEL);
318 if (!sd)
319 goto err_out1;
320
321 if (sysfs_alloc_ino(&sd->s_ino))
322 goto err_out2;
323
324 atomic_set(&sd->s_count, 1);
325 atomic_set(&sd->s_active, 0);
326
327 sd->s_name = name;
328 sd->s_mode = mode;
329 sd->s_flags = type;
330
331 return sd;
332
333 err_out2:
334 kmem_cache_free(sysfs_dir_cachep, sd);
335 err_out1:
336 kfree(dup_name);
337 return NULL;
338}
339
340/**
341 * sysfs_addrm_start - prepare for sysfs_dirent add/remove
342 * @acxt: pointer to sysfs_addrm_cxt to be used
343 * @parent_sd: parent sysfs_dirent
344 *
345 * This function is called when the caller is about to add or
346 * remove sysfs_dirent under @parent_sd. This function acquires
347 * sysfs_mutex. @acxt is used to keep and pass context to
348 * other addrm functions.
349 *
350 * LOCKING:
351 * Kernel thread context (may sleep). sysfs_mutex is locked on
352 * return.
353 */
354void sysfs_addrm_start(struct sysfs_addrm_cxt *acxt,
355 struct sysfs_dirent *parent_sd)
356{
357 memset(acxt, 0, sizeof(*acxt));
358 acxt->parent_sd = parent_sd;
359
360 mutex_lock(&sysfs_mutex);
361}
362
363/**
364 * __sysfs_add_one - add sysfs_dirent to parent without warning
365 * @acxt: addrm context to use
366 * @sd: sysfs_dirent to be added
367 *
368 * Get @acxt->parent_sd and set sd->s_parent to it and increment
369 * nlink of parent inode if @sd is a directory and link into the
370 * children list of the parent.
371 *
372 * This function should be called between calls to
373 * sysfs_addrm_start() and sysfs_addrm_finish() and should be
374 * passed the same @acxt as passed to sysfs_addrm_start().
375 *
376 * LOCKING:
377 * Determined by sysfs_addrm_start().
378 *
379 * RETURNS:
380 * 0 on success, -EEXIST if entry with the given name already
381 * exists.
382 */
383int __sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd)
384{
385 struct sysfs_inode_attrs *ps_iattr;
386
387 if (sysfs_find_dirent(acxt->parent_sd, sd->s_ns, sd->s_name))
388 return -EEXIST;
389
390 sd->s_parent = sysfs_get(acxt->parent_sd);
391
392 sysfs_link_sibling(sd);
393
394 /* Update timestamps on the parent */
395 ps_iattr = acxt->parent_sd->s_iattr;
396 if (ps_iattr) {
397 struct iattr *ps_iattrs = &ps_iattr->ia_iattr;
398 ps_iattrs->ia_ctime = ps_iattrs->ia_mtime = CURRENT_TIME;
399 }
400
401 return 0;
402}
403
404/**
405 * sysfs_pathname - return full path to sysfs dirent
406 * @sd: sysfs_dirent whose path we want
407 * @path: caller allocated buffer
408 *
409 * Gives the name "/" to the sysfs_root entry; any path returned
410 * is relative to wherever sysfs is mounted.
411 *
412 * XXX: does no error checking on @path size
413 */
414static char *sysfs_pathname(struct sysfs_dirent *sd, char *path)
415{
416 if (sd->s_parent) {
417 sysfs_pathname(sd->s_parent, path);
418 strcat(path, "/");
419 }
420 strcat(path, sd->s_name);
421 return path;
422}
423
424/**
425 * sysfs_add_one - add sysfs_dirent to parent
426 * @acxt: addrm context to use
427 * @sd: sysfs_dirent to be added
428 *
429 * Get @acxt->parent_sd and set sd->s_parent to it and increment
430 * nlink of parent inode if @sd is a directory and link into the
431 * children list of the parent.
432 *
433 * This function should be called between calls to
434 * sysfs_addrm_start() and sysfs_addrm_finish() and should be
435 * passed the same @acxt as passed to sysfs_addrm_start().
436 *
437 * LOCKING:
438 * Determined by sysfs_addrm_start().
439 *
440 * RETURNS:
441 * 0 on success, -EEXIST if entry with the given name already
442 * exists.
443 */
444int sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd)
445{
446 int ret;
447
448 ret = __sysfs_add_one(acxt, sd);
449 if (ret == -EEXIST) {
450 char *path = kzalloc(PATH_MAX, GFP_KERNEL);
451 WARN(1, KERN_WARNING
452 "sysfs: cannot create duplicate filename '%s'\n",
453 (path == NULL) ? sd->s_name :
454 strcat(strcat(sysfs_pathname(acxt->parent_sd, path), "/"),
455 sd->s_name));
456 kfree(path);
457 }
458
459 return ret;
460}
461
462/**
463 * sysfs_remove_one - remove sysfs_dirent from parent
464 * @acxt: addrm context to use
465 * @sd: sysfs_dirent to be removed
466 *
467 * Mark @sd removed and drop nlink of parent inode if @sd is a
468 * directory. @sd is unlinked from the children list.
469 *
470 * This function should be called between calls to
471 * sysfs_addrm_start() and sysfs_addrm_finish() and should be
472 * passed the same @acxt as passed to sysfs_addrm_start().
473 *
474 * LOCKING:
475 * Determined by sysfs_addrm_start().
476 */
477void sysfs_remove_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd)
478{
479 struct sysfs_inode_attrs *ps_iattr;
480
481 BUG_ON(sd->s_flags & SYSFS_FLAG_REMOVED);
482
483 sysfs_unlink_sibling(sd);
484
485 /* Update timestamps on the parent */
486 ps_iattr = acxt->parent_sd->s_iattr;
487 if (ps_iattr) {
488 struct iattr *ps_iattrs = &ps_iattr->ia_iattr;
489 ps_iattrs->ia_ctime = ps_iattrs->ia_mtime = CURRENT_TIME;
490 }
491
492 sd->s_flags |= SYSFS_FLAG_REMOVED;
493 sd->s_sibling = acxt->removed;
494 acxt->removed = sd;
495}
496
497/**
498 * sysfs_addrm_finish - finish up sysfs_dirent add/remove
499 * @acxt: addrm context to finish up
500 *
501 * Finish up sysfs_dirent add/remove. Resources acquired by
502 * sysfs_addrm_start() are released and removed sysfs_dirents are
503 * cleaned up.
504 *
505 * LOCKING:
506 * sysfs_mutex is released.
507 */
508void sysfs_addrm_finish(struct sysfs_addrm_cxt *acxt)
509{
510 /* release resources acquired by sysfs_addrm_start() */
511 mutex_unlock(&sysfs_mutex);
512
513 /* kill removed sysfs_dirents */
514 while (acxt->removed) {
515 struct sysfs_dirent *sd = acxt->removed;
516
517 acxt->removed = sd->s_sibling;
518 sd->s_sibling = NULL;
519
520 sysfs_deactivate(sd);
521 unmap_bin_file(sd);
522 sysfs_put(sd);
523 }
524}
525
526/**
527 * sysfs_find_dirent - find sysfs_dirent with the given name
528 * @parent_sd: sysfs_dirent to search under
529 * @name: name to look for
530 *
531 * Look for sysfs_dirent with name @name under @parent_sd.
532 *
533 * LOCKING:
534 * mutex_lock(sysfs_mutex)
535 *
536 * RETURNS:
537 * Pointer to sysfs_dirent if found, NULL if not.
538 */
539struct sysfs_dirent *sysfs_find_dirent(struct sysfs_dirent *parent_sd,
540 const void *ns,
541 const unsigned char *name)
542{
543 struct sysfs_dirent *sd;
544
545 for (sd = parent_sd->s_dir.children; sd; sd = sd->s_sibling) {
546 if (ns && sd->s_ns && (sd->s_ns != ns))
547 continue;
548 if (!strcmp(sd->s_name, name))
549 return sd;
550 }
551 return NULL;
552}
553
554/**
555 * sysfs_get_dirent - find and get sysfs_dirent with the given name
556 * @parent_sd: sysfs_dirent to search under
557 * @name: name to look for
558 *
559 * Look for sysfs_dirent with name @name under @parent_sd and get
560 * it if found.
561 *
562 * LOCKING:
563 * Kernel thread context (may sleep). Grabs sysfs_mutex.
564 *
565 * RETURNS:
566 * Pointer to sysfs_dirent if found, NULL if not.
567 */
568struct sysfs_dirent *sysfs_get_dirent(struct sysfs_dirent *parent_sd,
569 const void *ns,
570 const unsigned char *name)
571{
572 struct sysfs_dirent *sd;
573
574 mutex_lock(&sysfs_mutex);
575 sd = sysfs_find_dirent(parent_sd, ns, name);
576 sysfs_get(sd);
577 mutex_unlock(&sysfs_mutex);
578
579 return sd;
580}
581EXPORT_SYMBOL_GPL(sysfs_get_dirent);
582
583static int create_dir(struct kobject *kobj, struct sysfs_dirent *parent_sd,
584 enum kobj_ns_type type, const void *ns, const char *name,
585 struct sysfs_dirent **p_sd)
586{
587 umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO;
588 struct sysfs_addrm_cxt acxt;
589 struct sysfs_dirent *sd;
590 int rc;
591
592 /* allocate */
593 sd = sysfs_new_dirent(name, mode, SYSFS_DIR);
594 if (!sd)
595 return -ENOMEM;
596
597 sd->s_flags |= (type << SYSFS_NS_TYPE_SHIFT);
598 sd->s_ns = ns;
599 sd->s_dir.kobj = kobj;
600
601 /* link in */
602 sysfs_addrm_start(&acxt, parent_sd);
603 rc = sysfs_add_one(&acxt, sd);
604 sysfs_addrm_finish(&acxt);
605
606 if (rc == 0)
607 *p_sd = sd;
608 else
609 sysfs_put(sd);
610
611 return rc;
612}
613
614int sysfs_create_subdir(struct kobject *kobj, const char *name,
615 struct sysfs_dirent **p_sd)
616{
617 return create_dir(kobj, kobj->sd,
618 KOBJ_NS_TYPE_NONE, NULL, name, p_sd);
619}
620
621/**
622 * sysfs_read_ns_type: return associated ns_type
623 * @kobj: the kobject being queried
624 *
625 * Each kobject can be tagged with exactly one namespace type
626 * (i.e. network or user). Return the ns_type associated with
627 * this object if any
628 */
629static enum kobj_ns_type sysfs_read_ns_type(struct kobject *kobj)
630{
631 const struct kobj_ns_type_operations *ops;
632 enum kobj_ns_type type;
633
634 ops = kobj_child_ns_ops(kobj);
635 if (!ops)
636 return KOBJ_NS_TYPE_NONE;
637
638 type = ops->type;
639 BUG_ON(type <= KOBJ_NS_TYPE_NONE);
640 BUG_ON(type >= KOBJ_NS_TYPES);
641 BUG_ON(!kobj_ns_type_registered(type));
642
643 return type;
644}
645
646/**
647 * sysfs_create_dir - create a directory for an object.
648 * @kobj: object we're creating directory for.
649 */
650int sysfs_create_dir(struct kobject * kobj)
651{
652 enum kobj_ns_type type;
653 struct sysfs_dirent *parent_sd, *sd;
654 const void *ns = NULL;
655 int error = 0;
656
657 BUG_ON(!kobj);
658
659 if (kobj->parent)
660 parent_sd = kobj->parent->sd;
661 else
662 parent_sd = &sysfs_root;
663
664 if (sysfs_ns_type(parent_sd))
665 ns = kobj->ktype->namespace(kobj);
666 type = sysfs_read_ns_type(kobj);
667
668 error = create_dir(kobj, parent_sd, type, ns, kobject_name(kobj), &sd);
669 if (!error)
670 kobj->sd = sd;
671 return error;
672}
673
674static struct dentry * sysfs_lookup(struct inode *dir, struct dentry *dentry,
675 struct nameidata *nd)
676{
677 struct dentry *ret = NULL;
678 struct dentry *parent = dentry->d_parent;
679 struct sysfs_dirent *parent_sd = parent->d_fsdata;
680 struct sysfs_dirent *sd;
681 struct inode *inode;
682 enum kobj_ns_type type;
683 const void *ns;
684
685 mutex_lock(&sysfs_mutex);
686
687 type = sysfs_ns_type(parent_sd);
688 ns = sysfs_info(dir->i_sb)->ns[type];
689
690 sd = sysfs_find_dirent(parent_sd, ns, dentry->d_name.name);
691
692 /* no such entry */
693 if (!sd) {
694 ret = ERR_PTR(-ENOENT);
695 goto out_unlock;
696 }
697
698 /* attach dentry and inode */
699 inode = sysfs_get_inode(dir->i_sb, sd);
700 if (!inode) {
701 ret = ERR_PTR(-ENOMEM);
702 goto out_unlock;
703 }
704
705 /* instantiate and hash dentry */
706 ret = d_find_alias(inode);
707 if (!ret) {
708 d_set_d_op(dentry, &sysfs_dentry_ops);
709 dentry->d_fsdata = sysfs_get(sd);
710 d_add(dentry, inode);
711 } else {
712 d_move(ret, dentry);
713 iput(inode);
714 }
715
716 out_unlock:
717 mutex_unlock(&sysfs_mutex);
718 return ret;
719}
720
721const struct inode_operations sysfs_dir_inode_operations = {
722 .lookup = sysfs_lookup,
723 .permission = sysfs_permission,
724 .setattr = sysfs_setattr,
725 .getattr = sysfs_getattr,
726 .setxattr = sysfs_setxattr,
727};
728
729static void remove_dir(struct sysfs_dirent *sd)
730{
731 struct sysfs_addrm_cxt acxt;
732
733 sysfs_addrm_start(&acxt, sd->s_parent);
734 sysfs_remove_one(&acxt, sd);
735 sysfs_addrm_finish(&acxt);
736}
737
738void sysfs_remove_subdir(struct sysfs_dirent *sd)
739{
740 remove_dir(sd);
741}
742
743
744static void __sysfs_remove_dir(struct sysfs_dirent *dir_sd)
745{
746 struct sysfs_addrm_cxt acxt;
747 struct sysfs_dirent **pos;
748
749 if (!dir_sd)
750 return;
751
752 pr_debug("sysfs %s: removing dir\n", dir_sd->s_name);
753 sysfs_addrm_start(&acxt, dir_sd);
754 pos = &dir_sd->s_dir.children;
755 while (*pos) {
756 struct sysfs_dirent *sd = *pos;
757
758 if (sysfs_type(sd) != SYSFS_DIR)
759 sysfs_remove_one(&acxt, sd);
760 else
761 pos = &(*pos)->s_sibling;
762 }
763 sysfs_addrm_finish(&acxt);
764
765 remove_dir(dir_sd);
766}
767
768/**
769 * sysfs_remove_dir - remove an object's directory.
770 * @kobj: object.
771 *
772 * The only thing special about this is that we remove any files in
773 * the directory before we remove the directory, and we've inlined
774 * what used to be sysfs_rmdir() below, instead of calling separately.
775 */
776
777void sysfs_remove_dir(struct kobject * kobj)
778{
779 struct sysfs_dirent *sd = kobj->sd;
780
781 spin_lock(&sysfs_assoc_lock);
782 kobj->sd = NULL;
783 spin_unlock(&sysfs_assoc_lock);
784
785 __sysfs_remove_dir(sd);
786}
787
788int sysfs_rename(struct sysfs_dirent *sd,
789 struct sysfs_dirent *new_parent_sd, const void *new_ns,
790 const char *new_name)
791{
792 const char *dup_name = NULL;
793 int error;
794
795 mutex_lock(&sysfs_mutex);
796
797 error = 0;
798 if ((sd->s_parent == new_parent_sd) && (sd->s_ns == new_ns) &&
799 (strcmp(sd->s_name, new_name) == 0))
800 goto out; /* nothing to rename */
801
802 error = -EEXIST;
803 if (sysfs_find_dirent(new_parent_sd, new_ns, new_name))
804 goto out;
805
806 /* rename sysfs_dirent */
807 if (strcmp(sd->s_name, new_name) != 0) {
808 error = -ENOMEM;
809 new_name = dup_name = kstrdup(new_name, GFP_KERNEL);
810 if (!new_name)
811 goto out;
812
813 dup_name = sd->s_name;
814 sd->s_name = new_name;
815 }
816
817 /* Remove from old parent's list and insert into new parent's list. */
818 if (sd->s_parent != new_parent_sd) {
819 sysfs_unlink_sibling(sd);
820 sysfs_get(new_parent_sd);
821 sysfs_put(sd->s_parent);
822 sd->s_parent = new_parent_sd;
823 sysfs_link_sibling(sd);
824 }
825 sd->s_ns = new_ns;
826
827 error = 0;
828 out:
829 mutex_unlock(&sysfs_mutex);
830 kfree(dup_name);
831 return error;
832}
833
834int sysfs_rename_dir(struct kobject *kobj, const char *new_name)
835{
836 struct sysfs_dirent *parent_sd = kobj->sd->s_parent;
837 const void *new_ns = NULL;
838
839 if (sysfs_ns_type(parent_sd))
840 new_ns = kobj->ktype->namespace(kobj);
841
842 return sysfs_rename(kobj->sd, parent_sd, new_ns, new_name);
843}
844
845int sysfs_move_dir(struct kobject *kobj, struct kobject *new_parent_kobj)
846{
847 struct sysfs_dirent *sd = kobj->sd;
848 struct sysfs_dirent *new_parent_sd;
849 const void *new_ns = NULL;
850
851 BUG_ON(!sd->s_parent);
852 if (sysfs_ns_type(sd->s_parent))
853 new_ns = kobj->ktype->namespace(kobj);
854 new_parent_sd = new_parent_kobj && new_parent_kobj->sd ?
855 new_parent_kobj->sd : &sysfs_root;
856
857 return sysfs_rename(sd, new_parent_sd, new_ns, sd->s_name);
858}
859
860/* Relationship between s_mode and the DT_xxx types */
861static inline unsigned char dt_type(struct sysfs_dirent *sd)
862{
863 return (sd->s_mode >> 12) & 15;
864}
865
866static int sysfs_dir_release(struct inode *inode, struct file *filp)
867{
868 sysfs_put(filp->private_data);
869 return 0;
870}
871
872static struct sysfs_dirent *sysfs_dir_pos(const void *ns,
873 struct sysfs_dirent *parent_sd, ino_t ino, struct sysfs_dirent *pos)
874{
875 if (pos) {
876 int valid = !(pos->s_flags & SYSFS_FLAG_REMOVED) &&
877 pos->s_parent == parent_sd &&
878 ino == pos->s_ino;
879 sysfs_put(pos);
880 if (!valid)
881 pos = NULL;
882 }
883 if (!pos && (ino > 1) && (ino < INT_MAX)) {
884 pos = parent_sd->s_dir.children;
885 while (pos && (ino > pos->s_ino))
886 pos = pos->s_sibling;
887 }
888 while (pos && pos->s_ns && pos->s_ns != ns)
889 pos = pos->s_sibling;
890 return pos;
891}
892
893static struct sysfs_dirent *sysfs_dir_next_pos(const void *ns,
894 struct sysfs_dirent *parent_sd, ino_t ino, struct sysfs_dirent *pos)
895{
896 pos = sysfs_dir_pos(ns, parent_sd, ino, pos);
897 if (pos)
898 pos = pos->s_sibling;
899 while (pos && pos->s_ns && pos->s_ns != ns)
900 pos = pos->s_sibling;
901 return pos;
902}
903
904static int sysfs_readdir(struct file * filp, void * dirent, filldir_t filldir)
905{
906 struct dentry *dentry = filp->f_path.dentry;
907 struct sysfs_dirent * parent_sd = dentry->d_fsdata;
908 struct sysfs_dirent *pos = filp->private_data;
909 enum kobj_ns_type type;
910 const void *ns;
911 ino_t ino;
912
913 type = sysfs_ns_type(parent_sd);
914 ns = sysfs_info(dentry->d_sb)->ns[type];
915
916 if (filp->f_pos == 0) {
917 ino = parent_sd->s_ino;
918 if (filldir(dirent, ".", 1, filp->f_pos, ino, DT_DIR) == 0)
919 filp->f_pos++;
920 }
921 if (filp->f_pos == 1) {
922 if (parent_sd->s_parent)
923 ino = parent_sd->s_parent->s_ino;
924 else
925 ino = parent_sd->s_ino;
926 if (filldir(dirent, "..", 2, filp->f_pos, ino, DT_DIR) == 0)
927 filp->f_pos++;
928 }
929 mutex_lock(&sysfs_mutex);
930 for (pos = sysfs_dir_pos(ns, parent_sd, filp->f_pos, pos);
931 pos;
932 pos = sysfs_dir_next_pos(ns, parent_sd, filp->f_pos, pos)) {
933 const char * name;
934 unsigned int type;
935 int len, ret;
936
937 name = pos->s_name;
938 len = strlen(name);
939 ino = pos->s_ino;
940 type = dt_type(pos);
941 filp->f_pos = ino;
942 filp->private_data = sysfs_get(pos);
943
944 mutex_unlock(&sysfs_mutex);
945 ret = filldir(dirent, name, len, filp->f_pos, ino, type);
946 mutex_lock(&sysfs_mutex);
947 if (ret < 0)
948 break;
949 }
950 mutex_unlock(&sysfs_mutex);
951 if ((filp->f_pos > 1) && !pos) { /* EOF */
952 filp->f_pos = INT_MAX;
953 filp->private_data = NULL;
954 }
955 return 0;
956}
957
958
959const struct file_operations sysfs_dir_operations = {
960 .read = generic_read_dir,
961 .readdir = sysfs_readdir,
962 .release = sysfs_dir_release,
963 .llseek = generic_file_llseek,
964};