blob: d0deed3e60b530df1c7756de46352cce9e0d44eb [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * file.c - operations for regular (text) files.
3 */
4
5#include <linux/module.h>
Robert Love0eeca282005-07-12 17:06:03 -04006#include <linux/fsnotify.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -07007#include <linux/kobject.h>
Christoph Hellwig5f45f1a2005-06-23 00:09:12 -07008#include <linux/namei.h>
NeilBrown4508a7a2006-03-20 17:53:53 +11009#include <linux/poll.h>
Oliver Neukum94bebf42006-12-20 10:52:44 +010010#include <linux/list.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070011#include <asm/uaccess.h>
12#include <asm/semaphore.h>
13
14#include "sysfs.h"
15
Greg Kroah-Hartman823bccf2007-04-13 13:15:19 -070016#define to_sattr(a) container_of(a,struct subsys_attribute, attr)
Linus Torvalds1da177e2005-04-16 15:20:36 -070017
Martin Waitz3d410882005-06-23 22:05:21 -070018/*
Linus Torvalds1da177e2005-04-16 15:20:36 -070019 * Subsystem file operations.
20 * These operations allow subsystems to have files that can be
21 * read/written.
22 */
23static ssize_t
24subsys_attr_show(struct kobject * kobj, struct attribute * attr, char * page)
25{
Greg Kroah-Hartman823bccf2007-04-13 13:15:19 -070026 struct kset *kset = to_kset(kobj);
Linus Torvalds1da177e2005-04-16 15:20:36 -070027 struct subsys_attribute * sattr = to_sattr(attr);
Dmitry Torokhovc76d0ab2005-04-29 01:22:00 -050028 ssize_t ret = -EIO;
Linus Torvalds1da177e2005-04-16 15:20:36 -070029
30 if (sattr->show)
Greg Kroah-Hartman823bccf2007-04-13 13:15:19 -070031 ret = sattr->show(kset, page);
Linus Torvalds1da177e2005-04-16 15:20:36 -070032 return ret;
33}
34
35static ssize_t
36subsys_attr_store(struct kobject * kobj, struct attribute * attr,
37 const char * page, size_t count)
38{
Greg Kroah-Hartman823bccf2007-04-13 13:15:19 -070039 struct kset *kset = to_kset(kobj);
Linus Torvalds1da177e2005-04-16 15:20:36 -070040 struct subsys_attribute * sattr = to_sattr(attr);
Dmitry Torokhovc76d0ab2005-04-29 01:22:00 -050041 ssize_t ret = -EIO;
Linus Torvalds1da177e2005-04-16 15:20:36 -070042
43 if (sattr->store)
Greg Kroah-Hartman823bccf2007-04-13 13:15:19 -070044 ret = sattr->store(kset, page, count);
Linus Torvalds1da177e2005-04-16 15:20:36 -070045 return ret;
46}
47
48static struct sysfs_ops subsys_sysfs_ops = {
49 .show = subsys_attr_show,
50 .store = subsys_attr_store,
51};
52
Tejun Heo73107cb2007-06-14 03:45:16 +090053struct sysfs_buffer {
54 size_t count;
55 loff_t pos;
56 char * page;
57 struct sysfs_ops * ops;
58 struct semaphore sem;
59 int needs_read_fill;
60 int event;
61};
Linus Torvalds1da177e2005-04-16 15:20:36 -070062
63/**
64 * fill_read_buffer - allocate and fill buffer from object.
65 * @dentry: dentry pointer.
66 * @buffer: data buffer for file.
67 *
68 * Allocate @buffer->page, if it hasn't been already, then call the
69 * kobject's show() method to fill the buffer with this attribute's
70 * data.
Oliver Neukum82244b12007-01-02 08:48:08 +010071 * This is called only once, on the file's first read unless an error
72 * is returned.
Linus Torvalds1da177e2005-04-16 15:20:36 -070073 */
74static int fill_read_buffer(struct dentry * dentry, struct sysfs_buffer * buffer)
75{
Tejun Heo0ab66082007-06-14 03:45:16 +090076 struct sysfs_dirent *attr_sd = dentry->d_fsdata;
77 struct kobject *kobj = attr_sd->s_parent->s_elem.dir.kobj;
Linus Torvalds1da177e2005-04-16 15:20:36 -070078 struct sysfs_ops * ops = buffer->ops;
79 int ret = 0;
80 ssize_t count;
81
82 if (!buffer->page)
83 buffer->page = (char *) get_zeroed_page(GFP_KERNEL);
84 if (!buffer->page)
85 return -ENOMEM;
86
Tejun Heo0ab66082007-06-14 03:45:16 +090087 /* need attr_sd for attr and ops, its parent for kobj */
88 if (!sysfs_get_active_two(attr_sd))
89 return -ENODEV;
90
91 buffer->event = atomic_read(&attr_sd->s_event);
92 count = ops->show(kobj, attr_sd->s_elem.attr.attr, buffer->page);
93
94 sysfs_put_active_two(attr_sd);
95
Linus Torvalds1da177e2005-04-16 15:20:36 -070096 BUG_ON(count > (ssize_t)PAGE_SIZE);
Oliver Neukum82244b12007-01-02 08:48:08 +010097 if (count >= 0) {
98 buffer->needs_read_fill = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -070099 buffer->count = count;
Oliver Neukum82244b12007-01-02 08:48:08 +0100100 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700101 ret = count;
Oliver Neukum82244b12007-01-02 08:48:08 +0100102 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700103 return ret;
104}
105
Linus Torvalds1da177e2005-04-16 15:20:36 -0700106/**
107 * sysfs_read_file - read an attribute.
108 * @file: file pointer.
109 * @buf: buffer to fill.
110 * @count: number of bytes to read.
111 * @ppos: starting offset in file.
112 *
113 * Userspace wants to read an attribute file. The attribute descriptor
114 * is in the file's ->d_fsdata. The target object is in the directory's
115 * ->d_fsdata.
116 *
117 * We call fill_read_buffer() to allocate and fill the buffer from the
118 * object's show() method exactly once (if the read is happening from
119 * the beginning of the file). That should fill the entire buffer with
120 * all the data the object has to offer for that attribute.
121 * We then call flush_read_buffer() to copy the buffer to userspace
122 * in the increments specified.
123 */
124
125static ssize_t
126sysfs_read_file(struct file *file, char __user *buf, size_t count, loff_t *ppos)
127{
128 struct sysfs_buffer * buffer = file->private_data;
129 ssize_t retval = 0;
130
131 down(&buffer->sem);
132 if (buffer->needs_read_fill) {
Tejun Heo73107cb2007-06-14 03:45:16 +0900133 retval = fill_read_buffer(file->f_path.dentry,buffer);
Alan Sterne7b0d262007-03-15 15:51:28 -0400134 if (retval)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700135 goto out;
136 }
Zach Brown5c1fdf42006-10-03 01:16:06 -0700137 pr_debug("%s: count = %zd, ppos = %lld, buf = %s\n",
138 __FUNCTION__, count, *ppos, buffer->page);
Akinobu Mita92f4c702007-05-09 02:33:32 -0700139 retval = simple_read_from_buffer(buf, count, ppos, buffer->page,
140 buffer->count);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700141out:
142 up(&buffer->sem);
143 return retval;
144}
145
Linus Torvalds1da177e2005-04-16 15:20:36 -0700146/**
147 * fill_write_buffer - copy buffer from userspace.
148 * @buffer: data buffer for file.
Martin Waitz67be2dd2005-05-01 08:59:26 -0700149 * @buf: data from user.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700150 * @count: number of bytes in @userbuf.
151 *
152 * Allocate @buffer->page if it hasn't been already, then
153 * copy the user-supplied buffer into it.
154 */
155
156static int
157fill_write_buffer(struct sysfs_buffer * buffer, const char __user * buf, size_t count)
158{
159 int error;
160
161 if (!buffer->page)
162 buffer->page = (char *)get_zeroed_page(GFP_KERNEL);
163 if (!buffer->page)
164 return -ENOMEM;
165
166 if (count >= PAGE_SIZE)
Greg Kroah-Hartman6e0dd742006-03-31 15:37:06 -0800167 count = PAGE_SIZE - 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700168 error = copy_from_user(buffer->page,buf,count);
169 buffer->needs_read_fill = 1;
Thomas Maier035ed7a2006-10-22 19:17:47 +0200170 /* if buf is assumed to contain a string, terminate it by \0,
171 so e.g. sscanf() can scan the string easily */
172 buffer->page[count] = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700173 return error ? -EFAULT : count;
174}
175
176
177/**
178 * flush_write_buffer - push buffer to kobject.
Martin Waitz3d410882005-06-23 22:05:21 -0700179 * @dentry: dentry to the attribute
Linus Torvalds1da177e2005-04-16 15:20:36 -0700180 * @buffer: data buffer for file.
Martin Waitz3d410882005-06-23 22:05:21 -0700181 * @count: number of bytes
Linus Torvalds1da177e2005-04-16 15:20:36 -0700182 *
183 * Get the correct pointers for the kobject and the attribute we're
184 * dealing with, then call the store() method for the attribute,
185 * passing the buffer that we acquired in fill_write_buffer().
186 */
187
Tejun Heo0ab66082007-06-14 03:45:16 +0900188static int
Linus Torvalds1da177e2005-04-16 15:20:36 -0700189flush_write_buffer(struct dentry * dentry, struct sysfs_buffer * buffer, size_t count)
190{
Tejun Heo3e519032007-06-14 03:45:15 +0900191 struct sysfs_dirent *attr_sd = dentry->d_fsdata;
Tejun Heo0ab66082007-06-14 03:45:16 +0900192 struct kobject *kobj = attr_sd->s_parent->s_elem.dir.kobj;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700193 struct sysfs_ops * ops = buffer->ops;
Tejun Heo0ab66082007-06-14 03:45:16 +0900194 int rc;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700195
Tejun Heo0ab66082007-06-14 03:45:16 +0900196 /* need attr_sd for attr and ops, its parent for kobj */
197 if (!sysfs_get_active_two(attr_sd))
198 return -ENODEV;
199
200 rc = ops->store(kobj, attr_sd->s_elem.attr.attr, buffer->page, count);
201
202 sysfs_put_active_two(attr_sd);
203
204 return rc;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700205}
206
207
208/**
209 * sysfs_write_file - write an attribute.
210 * @file: file pointer
211 * @buf: data to write
212 * @count: number of bytes
213 * @ppos: starting offset
214 *
215 * Similar to sysfs_read_file(), though working in the opposite direction.
216 * We allocate and fill the data from the user in fill_write_buffer(),
217 * then push it to the kobject in flush_write_buffer().
218 * There is no easy way for us to know if userspace is only doing a partial
219 * write, so we don't support them. We expect the entire buffer to come
220 * on the first write.
221 * Hint: if you're writing a value, first read the file, modify only the
222 * the value you're changing, then write entire buffer back.
223 */
224
225static ssize_t
226sysfs_write_file(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
227{
228 struct sysfs_buffer * buffer = file->private_data;
229 ssize_t len;
230
231 down(&buffer->sem);
232 len = fill_write_buffer(buffer, buf, count);
233 if (len > 0)
Josef "Jeff" Sipekf427f5d2006-12-08 02:36:36 -0800234 len = flush_write_buffer(file->f_path.dentry, buffer, len);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700235 if (len > 0)
236 *ppos += len;
237 up(&buffer->sem);
238 return len;
239}
240
Oliver Neukum94bebf42006-12-20 10:52:44 +0100241static int sysfs_open_file(struct inode *inode, struct file *file)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700242{
Tejun Heo3e519032007-06-14 03:45:15 +0900243 struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
Tejun Heo0ab66082007-06-14 03:45:16 +0900244 struct kobject *kobj = attr_sd->s_parent->s_elem.dir.kobj;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700245 struct sysfs_buffer * buffer;
246 struct sysfs_ops * ops = NULL;
Tejun Heo0ab66082007-06-14 03:45:16 +0900247 int error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700248
Tejun Heo0ab66082007-06-14 03:45:16 +0900249 /* need attr_sd for attr and ops, its parent for kobj */
250 if (!sysfs_get_active_two(attr_sd))
251 return -ENODEV;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700252
Linus Torvalds1da177e2005-04-16 15:20:36 -0700253 /* if the kobject has no ktype, then we assume that it is a subsystem
254 * itself, and use ops for it.
255 */
256 if (kobj->kset && kobj->kset->ktype)
257 ops = kobj->kset->ktype->sysfs_ops;
258 else if (kobj->ktype)
259 ops = kobj->ktype->sysfs_ops;
260 else
261 ops = &subsys_sysfs_ops;
262
Tejun Heo73107cb2007-06-14 03:45:16 +0900263 error = -EACCES;
264
Linus Torvalds1da177e2005-04-16 15:20:36 -0700265 /* No sysfs operations, either from having no subsystem,
266 * or the subsystem have no operations.
267 */
268 if (!ops)
Tejun Heo7b595752007-06-14 03:45:17 +0900269 goto err_out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700270
271 /* File needs write support.
272 * The inode's perms must say it's ok,
273 * and we must have a store method.
274 */
275 if (file->f_mode & FMODE_WRITE) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700276 if (!(inode->i_mode & S_IWUGO) || !ops->store)
Tejun Heo7b595752007-06-14 03:45:17 +0900277 goto err_out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700278 }
279
280 /* File needs read support.
281 * The inode's perms must say it's ok, and we there
282 * must be a show method for it.
283 */
284 if (file->f_mode & FMODE_READ) {
285 if (!(inode->i_mode & S_IRUGO) || !ops->show)
Tejun Heo7b595752007-06-14 03:45:17 +0900286 goto err_out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700287 }
288
289 /* No error? Great, allocate a buffer for the file, and store it
290 * it in file->private_data for easy access.
291 */
Tejun Heo0ab66082007-06-14 03:45:16 +0900292 error = -ENOMEM;
Eric Sesterhenn58d49282006-02-22 11:18:15 +0100293 buffer = kzalloc(sizeof(struct sysfs_buffer), GFP_KERNEL);
Tejun Heo0ab66082007-06-14 03:45:16 +0900294 if (!buffer)
Tejun Heo7b595752007-06-14 03:45:17 +0900295 goto err_out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700296
Tejun Heo0ab66082007-06-14 03:45:16 +0900297 init_MUTEX(&buffer->sem);
298 buffer->needs_read_fill = 1;
299 buffer->ops = ops;
Tejun Heo0ab66082007-06-14 03:45:16 +0900300 file->private_data = buffer;
301
302 /* open succeeded, put active references and pin attr_sd */
303 sysfs_put_active_two(attr_sd);
304 sysfs_get(attr_sd);
305 return 0;
306
Tejun Heo7b595752007-06-14 03:45:17 +0900307 err_out:
Tejun Heo0ab66082007-06-14 03:45:16 +0900308 sysfs_put_active_two(attr_sd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700309 return error;
310}
311
Linus Torvalds1da177e2005-04-16 15:20:36 -0700312static int sysfs_release(struct inode * inode, struct file * filp)
313{
Tejun Heo3e519032007-06-14 03:45:15 +0900314 struct sysfs_dirent *attr_sd = filp->f_path.dentry->d_fsdata;
Tejun Heo73107cb2007-06-14 03:45:16 +0900315 struct sysfs_buffer *buffer = filp->private_data;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700316
Tejun Heo0ab66082007-06-14 03:45:16 +0900317 sysfs_put(attr_sd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700318
319 if (buffer) {
320 if (buffer->page)
321 free_page((unsigned long)buffer->page);
322 kfree(buffer);
323 }
324 return 0;
325}
326
NeilBrown4508a7a2006-03-20 17:53:53 +1100327/* Sysfs attribute files are pollable. The idea is that you read
328 * the content and then you use 'poll' or 'select' to wait for
329 * the content to change. When the content changes (assuming the
330 * manager for the kobject supports notification), poll will
331 * return POLLERR|POLLPRI, and select will return the fd whether
332 * it is waiting for read, write, or exceptions.
333 * Once poll/select indicates that the value has changed, you
334 * need to close and re-open the file, as simply seeking and reading
335 * again will not get new data, or reset the state of 'poll'.
336 * Reminder: this only works for attributes which actively support
337 * it, and it is not possible to test an attribute from userspace
338 * to see if it supports poll (Nether 'poll' or 'select' return
339 * an appropriate error code). When in doubt, set a suitable timeout value.
340 */
341static unsigned int sysfs_poll(struct file *filp, poll_table *wait)
342{
343 struct sysfs_buffer * buffer = filp->private_data;
Tejun Heo0ab66082007-06-14 03:45:16 +0900344 struct sysfs_dirent *attr_sd = filp->f_path.dentry->d_fsdata;
345 struct kobject *kobj = attr_sd->s_parent->s_elem.dir.kobj;
346
347 /* need parent for the kobj, grab both */
348 if (!sysfs_get_active_two(attr_sd))
349 goto trigger;
NeilBrown4508a7a2006-03-20 17:53:53 +1100350
351 poll_wait(filp, &kobj->poll, wait);
352
Tejun Heo0ab66082007-06-14 03:45:16 +0900353 sysfs_put_active_two(attr_sd);
NeilBrown4508a7a2006-03-20 17:53:53 +1100354
Tejun Heo0ab66082007-06-14 03:45:16 +0900355 if (buffer->event != atomic_read(&attr_sd->s_event))
356 goto trigger;
357
358 return 0;
359
360 trigger:
361 buffer->needs_read_fill = 1;
362 return POLLERR|POLLPRI;
NeilBrown4508a7a2006-03-20 17:53:53 +1100363}
364
365
366static struct dentry *step_down(struct dentry *dir, const char * name)
367{
368 struct dentry * de;
369
370 if (dir == NULL || dir->d_inode == NULL)
371 return NULL;
372
373 mutex_lock(&dir->d_inode->i_mutex);
374 de = lookup_one_len(name, dir, strlen(name));
375 mutex_unlock(&dir->d_inode->i_mutex);
376 dput(dir);
377 if (IS_ERR(de))
378 return NULL;
379 if (de->d_inode == NULL) {
380 dput(de);
381 return NULL;
382 }
383 return de;
384}
385
386void sysfs_notify(struct kobject * k, char *dir, char *attr)
387{
Tejun Heo608e2662007-06-14 04:27:22 +0900388 struct dentry *de = k->sd->s_dentry;
NeilBrown4508a7a2006-03-20 17:53:53 +1100389 if (de)
390 dget(de);
391 if (de && dir)
392 de = step_down(de, dir);
393 if (de && attr)
394 de = step_down(de, attr);
395 if (de) {
396 struct sysfs_dirent * sd = de->d_fsdata;
397 if (sd)
398 atomic_inc(&sd->s_event);
399 wake_up_interruptible(&k->poll);
400 dput(de);
401 }
402}
403EXPORT_SYMBOL_GPL(sysfs_notify);
404
Arjan van de Ven4b6f5d22006-03-28 01:56:42 -0800405const struct file_operations sysfs_file_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700406 .read = sysfs_read_file,
407 .write = sysfs_write_file,
408 .llseek = generic_file_llseek,
409 .open = sysfs_open_file,
410 .release = sysfs_release,
NeilBrown4508a7a2006-03-20 17:53:53 +1100411 .poll = sysfs_poll,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700412};
413
414
Tejun Heo608e2662007-06-14 04:27:22 +0900415int sysfs_add_file(struct sysfs_dirent *dir_sd, const struct attribute *attr,
416 int type)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700417{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700418 umode_t mode = (attr->mode & S_IALLUGO) | S_IFREG;
Tejun Heoa26cd722007-06-14 03:45:14 +0900419 struct sysfs_dirent *sd;
Tejun Heoa26cd722007-06-14 03:45:14 +0900420
Tejun Heo3e519032007-06-14 03:45:15 +0900421 sd = sysfs_new_dirent(attr->name, mode, type);
Tejun Heo3007e992007-06-14 04:27:23 +0900422 if (!sd)
423 return -ENOMEM;
Tejun Heo3e519032007-06-14 03:45:15 +0900424 sd->s_elem.attr.attr = (void *)attr;
Tejun Heoa26cd722007-06-14 03:45:14 +0900425
Tejun Heo3007e992007-06-14 04:27:23 +0900426 mutex_lock(&sysfs_mutex);
427
428 if (!sysfs_find_dirent(dir_sd, attr->name)) {
429 sysfs_attach_dirent(sd, dir_sd, NULL);
430 sd = NULL;
431 }
432
433 mutex_unlock(&sysfs_mutex);
434
435 if (sd) {
436 sysfs_put(sd);
437 return -EEXIST;
438 }
439 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700440}
441
442
443/**
444 * sysfs_create_file - create an attribute file for an object.
445 * @kobj: object we're creating for.
446 * @attr: atrribute descriptor.
447 */
448
449int sysfs_create_file(struct kobject * kobj, const struct attribute * attr)
450{
Tejun Heo608e2662007-06-14 04:27:22 +0900451 BUG_ON(!kobj || !kobj->sd || !attr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700452
Tejun Heo608e2662007-06-14 04:27:22 +0900453 return sysfs_add_file(kobj->sd, attr, SYSFS_KOBJ_ATTR);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700454
455}
456
457
458/**
Alan Sterndfa87c82007-02-20 15:02:44 -0500459 * sysfs_add_file_to_group - add an attribute file to a pre-existing group.
460 * @kobj: object we're acting for.
461 * @attr: attribute descriptor.
462 * @group: group name.
463 */
464int sysfs_add_file_to_group(struct kobject *kobj,
465 const struct attribute *attr, const char *group)
466{
Tejun Heo608e2662007-06-14 04:27:22 +0900467 struct sysfs_dirent *dir_sd;
Alan Sterndfa87c82007-02-20 15:02:44 -0500468 int error;
469
Tejun Heo608e2662007-06-14 04:27:22 +0900470 dir_sd = sysfs_get_dirent(kobj->sd, group);
471 if (!dir_sd)
472 return -ENOENT;
473
474 error = sysfs_add_file(dir_sd, attr, SYSFS_KOBJ_ATTR);
475 sysfs_put(dir_sd);
476
Alan Sterndfa87c82007-02-20 15:02:44 -0500477 return error;
478}
479EXPORT_SYMBOL_GPL(sysfs_add_file_to_group);
480
481
482/**
Linus Torvalds1da177e2005-04-16 15:20:36 -0700483 * sysfs_update_file - update the modified timestamp on an object attribute.
484 * @kobj: object we're acting for.
485 * @attr: attribute descriptor.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700486 */
487int sysfs_update_file(struct kobject * kobj, const struct attribute * attr)
488{
Tejun Heo608e2662007-06-14 04:27:22 +0900489 struct dentry *dir = kobj->sd->s_dentry;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700490 struct dentry * victim;
491 int res = -ENOENT;
492
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800493 mutex_lock(&dir->d_inode->i_mutex);
Christoph Hellwig5f45f1a2005-06-23 00:09:12 -0700494 victim = lookup_one_len(attr->name, dir, strlen(attr->name));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700495 if (!IS_ERR(victim)) {
496 /* make sure dentry is really there */
497 if (victim->d_inode &&
498 (victim->d_parent->d_inode == dir->d_inode)) {
499 victim->d_inode->i_mtime = CURRENT_TIME;
Robert Love0eeca282005-07-12 17:06:03 -0400500 fsnotify_modify(victim);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700501 res = 0;
502 } else
503 d_drop(victim);
504
505 /**
Hidetoshi Seto97a50182006-09-20 16:49:02 +0900506 * Drop the reference acquired from lookup_one_len() above.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700507 */
508 dput(victim);
509 }
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800510 mutex_unlock(&dir->d_inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700511
512 return res;
513}
514
515
516/**
Kay Sievers31e5abe2005-04-18 21:57:32 -0700517 * sysfs_chmod_file - update the modified mode value on an object attribute.
518 * @kobj: object we're acting for.
519 * @attr: attribute descriptor.
520 * @mode: file permissions.
521 *
522 */
523int sysfs_chmod_file(struct kobject *kobj, struct attribute *attr, mode_t mode)
524{
Tejun Heo608e2662007-06-14 04:27:22 +0900525 struct dentry *dir = kobj->sd->s_dentry;
Kay Sievers31e5abe2005-04-18 21:57:32 -0700526 struct dentry *victim;
Maneesh Sonibc062b12005-07-29 12:13:35 -0700527 struct inode * inode;
528 struct iattr newattrs;
Kay Sievers31e5abe2005-04-18 21:57:32 -0700529 int res = -ENOENT;
530
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800531 mutex_lock(&dir->d_inode->i_mutex);
Christoph Hellwig5f45f1a2005-06-23 00:09:12 -0700532 victim = lookup_one_len(attr->name, dir, strlen(attr->name));
Kay Sievers31e5abe2005-04-18 21:57:32 -0700533 if (!IS_ERR(victim)) {
534 if (victim->d_inode &&
535 (victim->d_parent->d_inode == dir->d_inode)) {
Maneesh Sonibc062b12005-07-29 12:13:35 -0700536 inode = victim->d_inode;
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800537 mutex_lock(&inode->i_mutex);
Maneesh Sonibc062b12005-07-29 12:13:35 -0700538 newattrs.ia_mode = (mode & S_IALLUGO) |
539 (inode->i_mode & ~S_IALLUGO);
540 newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
541 res = notify_change(victim, &newattrs);
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800542 mutex_unlock(&inode->i_mutex);
Kay Sievers31e5abe2005-04-18 21:57:32 -0700543 }
Maneesh Sonibc062b12005-07-29 12:13:35 -0700544 dput(victim);
Kay Sievers31e5abe2005-04-18 21:57:32 -0700545 }
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800546 mutex_unlock(&dir->d_inode->i_mutex);
Kay Sievers31e5abe2005-04-18 21:57:32 -0700547
548 return res;
549}
550EXPORT_SYMBOL_GPL(sysfs_chmod_file);
551
552
553/**
Linus Torvalds1da177e2005-04-16 15:20:36 -0700554 * sysfs_remove_file - remove an object attribute.
555 * @kobj: object we're acting for.
556 * @attr: attribute descriptor.
557 *
558 * Hash the attribute name and kill the victim.
559 */
560
561void sysfs_remove_file(struct kobject * kobj, const struct attribute * attr)
562{
Tejun Heo608e2662007-06-14 04:27:22 +0900563 sysfs_hash_and_remove(kobj->sd, attr->name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700564}
565
566
Alan Sterndfa87c82007-02-20 15:02:44 -0500567/**
568 * sysfs_remove_file_from_group - remove an attribute file from a group.
569 * @kobj: object we're acting for.
570 * @attr: attribute descriptor.
571 * @group: group name.
572 */
573void sysfs_remove_file_from_group(struct kobject *kobj,
574 const struct attribute *attr, const char *group)
575{
Tejun Heo608e2662007-06-14 04:27:22 +0900576 struct sysfs_dirent *dir_sd;
Alan Sterndfa87c82007-02-20 15:02:44 -0500577
Tejun Heo608e2662007-06-14 04:27:22 +0900578 dir_sd = sysfs_get_dirent(kobj->sd, group);
579 if (dir_sd) {
580 sysfs_hash_and_remove(dir_sd, attr->name);
581 sysfs_put(dir_sd);
Alan Sterndfa87c82007-02-20 15:02:44 -0500582 }
583}
584EXPORT_SYMBOL_GPL(sysfs_remove_file_from_group);
585
Alan Sternd9a9cdf2007-03-15 15:50:34 -0400586struct sysfs_schedule_callback_struct {
587 struct kobject *kobj;
588 void (*func)(void *);
589 void *data;
Alan Stern523ded72007-04-26 00:12:04 -0700590 struct module *owner;
Alan Sternd9a9cdf2007-03-15 15:50:34 -0400591 struct work_struct work;
592};
593
594static void sysfs_schedule_callback_work(struct work_struct *work)
595{
596 struct sysfs_schedule_callback_struct *ss = container_of(work,
597 struct sysfs_schedule_callback_struct, work);
598
599 (ss->func)(ss->data);
600 kobject_put(ss->kobj);
Alan Stern523ded72007-04-26 00:12:04 -0700601 module_put(ss->owner);
Alan Sternd9a9cdf2007-03-15 15:50:34 -0400602 kfree(ss);
603}
604
605/**
606 * sysfs_schedule_callback - helper to schedule a callback for a kobject
607 * @kobj: object we're acting for.
608 * @func: callback function to invoke later.
609 * @data: argument to pass to @func.
Alan Stern523ded72007-04-26 00:12:04 -0700610 * @owner: module owning the callback code
Alan Sternd9a9cdf2007-03-15 15:50:34 -0400611 *
612 * sysfs attribute methods must not unregister themselves or their parent
613 * kobject (which would amount to the same thing). Attempts to do so will
614 * deadlock, since unregistration is mutually exclusive with driver
615 * callbacks.
616 *
617 * Instead methods can call this routine, which will attempt to allocate
618 * and schedule a workqueue request to call back @func with @data as its
619 * argument in the workqueue's process context. @kobj will be pinned
620 * until @func returns.
621 *
622 * Returns 0 if the request was submitted, -ENOMEM if storage could not
Alan Stern523ded72007-04-26 00:12:04 -0700623 * be allocated, -ENODEV if a reference to @owner isn't available.
Alan Sternd9a9cdf2007-03-15 15:50:34 -0400624 */
625int sysfs_schedule_callback(struct kobject *kobj, void (*func)(void *),
Alan Stern523ded72007-04-26 00:12:04 -0700626 void *data, struct module *owner)
Alan Sternd9a9cdf2007-03-15 15:50:34 -0400627{
628 struct sysfs_schedule_callback_struct *ss;
629
Alan Stern523ded72007-04-26 00:12:04 -0700630 if (!try_module_get(owner))
631 return -ENODEV;
Alan Sternd9a9cdf2007-03-15 15:50:34 -0400632 ss = kmalloc(sizeof(*ss), GFP_KERNEL);
Alan Stern523ded72007-04-26 00:12:04 -0700633 if (!ss) {
634 module_put(owner);
Alan Sternd9a9cdf2007-03-15 15:50:34 -0400635 return -ENOMEM;
Alan Stern523ded72007-04-26 00:12:04 -0700636 }
Alan Sternd9a9cdf2007-03-15 15:50:34 -0400637 kobject_get(kobj);
638 ss->kobj = kobj;
639 ss->func = func;
640 ss->data = data;
Alan Stern523ded72007-04-26 00:12:04 -0700641 ss->owner = owner;
Alan Sternd9a9cdf2007-03-15 15:50:34 -0400642 INIT_WORK(&ss->work, sysfs_schedule_callback_work);
643 schedule_work(&ss->work);
644 return 0;
645}
646EXPORT_SYMBOL_GPL(sysfs_schedule_callback);
647
Alan Sterndfa87c82007-02-20 15:02:44 -0500648
Linus Torvalds1da177e2005-04-16 15:20:36 -0700649EXPORT_SYMBOL_GPL(sysfs_create_file);
650EXPORT_SYMBOL_GPL(sysfs_remove_file);
651EXPORT_SYMBOL_GPL(sysfs_update_file);