1/*
2 * fs/sysfs/bin.c - sysfs binary file implementation
3 *
4 * Copyright (c) 2003 Patrick Mochel
5 * Copyright (c) 2003 Matthew Wilcox
6 * Copyright (c) 2004 Silicon Graphics, Inc.
7 * Copyright (c) 2007 SUSE Linux Products GmbH
8 * Copyright (c) 2007 Tejun Heo <teheo@suse.de>
9 *
10 * This file is released under the GPLv2.
11 *
12 * Please see Documentation/filesystems/sysfs.txt for more information.
13 */
14
15#undef DEBUG
16
17#include <linux/errno.h>
18#include <linux/fs.h>
19#include <linux/kernel.h>
20#include <linux/kobject.h>
21#include <linux/module.h>
22#include <linux/slab.h>
23#include <linux/mutex.h>
24#include <linux/mm.h>
25
26#include <asm/uaccess.h>
27
28#include "sysfs.h"
29
30/*
31 * There's one bin_buffer for each open file.
32 *
33 * filp->private_data points to bin_buffer and
34 * sysfs_dirent->s_bin_attr.buffers points to a the bin_buffer s
35 * sysfs_dirent->s_bin_attr.buffers is protected by sysfs_bin_lock
36 */
37static DEFINE_MUTEX(sysfs_bin_lock);
38
39struct bin_buffer {
40	struct mutex			mutex;
41	void				*buffer;
42	int				mmapped;
43	const struct vm_operations_struct *vm_ops;
44	struct file			*file;
45	struct hlist_node		list;
46};
47
48static int
49fill_read(struct file *file, char *buffer, loff_t off, size_t count)
50{
51	struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
52	struct bin_attribute *attr = attr_sd->s_bin_attr.bin_attr;
53	struct kobject *kobj = attr_sd->s_parent->s_dir.kobj;
54	int rc;
55
56	/* need attr_sd for attr, its parent for kobj */
57	if (!sysfs_get_active(attr_sd))
58		return -ENODEV;
59
60	rc = -EIO;
61	if (attr->read)
62		rc = attr->read(file, kobj, attr, buffer, off, count);
63
64	sysfs_put_active(attr_sd);
65
66	return rc;
67}
68
69static ssize_t
70read(struct file *file, char __user *userbuf, size_t bytes, loff_t *off)
71{
72	struct bin_buffer *bb = file->private_data;
73	int size = file->f_path.dentry->d_inode->i_size;
74	loff_t offs = *off;
75	int count = min_t(size_t, bytes, PAGE_SIZE);
76	char *temp;
77
78	if (!bytes)
79		return 0;
80
81	if (size) {
82		if (offs > size)
83			return 0;
84		if (offs + count > size)
85			count = size - offs;
86	}
87
88	temp = kmalloc(count, GFP_KERNEL);
89	if (!temp)
90		return -ENOMEM;
91
92	mutex_lock(&bb->mutex);
93
94	count = fill_read(file, bb->buffer, offs, count);
95	if (count < 0) {
96		mutex_unlock(&bb->mutex);
97		goto out_free;
98	}
99
100	memcpy(temp, bb->buffer, count);
101
102	mutex_unlock(&bb->mutex);
103
104	if (copy_to_user(userbuf, temp, count)) {
105		count = -EFAULT;
106		goto out_free;
107	}
108
109	pr_debug("offs = %lld, *off = %lld, count = %d\n", offs, *off, count);
110
111	*off = offs + count;
112
113 out_free:
114	kfree(temp);
115	return count;
116}
117
118static int
119flush_write(struct file *file, char *buffer, loff_t offset, size_t count)
120{
121	struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
122	struct bin_attribute *attr = attr_sd->s_bin_attr.bin_attr;
123	struct kobject *kobj = attr_sd->s_parent->s_dir.kobj;
124	int rc;
125
126	/* need attr_sd for attr, its parent for kobj */
127	if (!sysfs_get_active(attr_sd))
128		return -ENODEV;
129
130	rc = -EIO;
131	if (attr->write)
132		rc = attr->write(file, kobj, attr, buffer, offset, count);
133
134	sysfs_put_active(attr_sd);
135
136	return rc;
137}
138
139static ssize_t write(struct file *file, const char __user *userbuf,
140		     size_t bytes, loff_t *off)
141{
142	struct bin_buffer *bb = file->private_data;
143	int size = file->f_path.dentry->d_inode->i_size;
144	loff_t offs = *off;
145	int count = min_t(size_t, bytes, PAGE_SIZE);
146	char *temp;
147
148	if (!bytes)
149		return 0;
150
151	if (size) {
152		if (offs > size)
153			return 0;
154		if (offs + count > size)
155			count = size - offs;
156	}
157
158	temp = memdup_user(userbuf, count);
159	if (IS_ERR(temp))
160		return PTR_ERR(temp);
161
162	mutex_lock(&bb->mutex);
163
164	memcpy(bb->buffer, temp, count);
165
166	count = flush_write(file, bb->buffer, offs, count);
167	mutex_unlock(&bb->mutex);
168
169	if (count > 0)
170		*off = offs + count;
171
172	kfree(temp);
173	return count;
174}
175
176static void bin_vma_open(struct vm_area_struct *vma)
177{
178	struct file *file = vma->vm_file;
179	struct bin_buffer *bb = file->private_data;
180	struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
181
182	if (!bb->vm_ops || !bb->vm_ops->open)
183		return;
184
185	if (!sysfs_get_active(attr_sd))
186		return;
187
188	bb->vm_ops->open(vma);
189
190	sysfs_put_active(attr_sd);
191}
192
193static void bin_vma_close(struct vm_area_struct *vma)
194{
195	struct file *file = vma->vm_file;
196	struct bin_buffer *bb = file->private_data;
197	struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
198
199	if (!bb->vm_ops || !bb->vm_ops->close)
200		return;
201
202	if (!sysfs_get_active(attr_sd))
203		return;
204
205	bb->vm_ops->close(vma);
206
207	sysfs_put_active(attr_sd);
208}
209
210static int bin_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
211{
212	struct file *file = vma->vm_file;
213	struct bin_buffer *bb = file->private_data;
214	struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
215	int ret;
216
217	if (!bb->vm_ops || !bb->vm_ops->fault)
218		return VM_FAULT_SIGBUS;
219
220	if (!sysfs_get_active(attr_sd))
221		return VM_FAULT_SIGBUS;
222
223	ret = bb->vm_ops->fault(vma, vmf);
224
225	sysfs_put_active(attr_sd);
226	return ret;
227}
228
229static int bin_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
230{
231	struct file *file = vma->vm_file;
232	struct bin_buffer *bb = file->private_data;
233	struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
234	int ret;
235
236	if (!bb->vm_ops)
237		return VM_FAULT_SIGBUS;
238
239	if (!bb->vm_ops->page_mkwrite)
240		return 0;
241
242	if (!sysfs_get_active(attr_sd))
243		return VM_FAULT_SIGBUS;
244
245	ret = bb->vm_ops->page_mkwrite(vma, vmf);
246
247	sysfs_put_active(attr_sd);
248	return ret;
249}
250
251static int bin_access(struct vm_area_struct *vma, unsigned long addr,
252		  void *buf, int len, int write)
253{
254	struct file *file = vma->vm_file;
255	struct bin_buffer *bb = file->private_data;
256	struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
257	int ret;
258
259	if (!bb->vm_ops || !bb->vm_ops->access)
260		return -EINVAL;
261
262	if (!sysfs_get_active(attr_sd))
263		return -EINVAL;
264
265	ret = bb->vm_ops->access(vma, addr, buf, len, write);
266
267	sysfs_put_active(attr_sd);
268	return ret;
269}
270
271#ifdef CONFIG_NUMA
272static int bin_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
273{
274	struct file *file = vma->vm_file;
275	struct bin_buffer *bb = file->private_data;
276	struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
277	int ret;
278
279	if (!bb->vm_ops || !bb->vm_ops->set_policy)
280		return 0;
281
282	if (!sysfs_get_active(attr_sd))
283		return -EINVAL;
284
285	ret = bb->vm_ops->set_policy(vma, new);
286
287	sysfs_put_active(attr_sd);
288	return ret;
289}
290
291static struct mempolicy *bin_get_policy(struct vm_area_struct *vma,
292					unsigned long addr)
293{
294	struct file *file = vma->vm_file;
295	struct bin_buffer *bb = file->private_data;
296	struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
297	struct mempolicy *pol;
298
299	if (!bb->vm_ops || !bb->vm_ops->get_policy)
300		return vma->vm_policy;
301
302	if (!sysfs_get_active(attr_sd))
303		return vma->vm_policy;
304
305	pol = bb->vm_ops->get_policy(vma, addr);
306
307	sysfs_put_active(attr_sd);
308	return pol;
309}
310
311static int bin_migrate(struct vm_area_struct *vma, const nodemask_t *from,
312			const nodemask_t *to, unsigned long flags)
313{
314	struct file *file = vma->vm_file;
315	struct bin_buffer *bb = file->private_data;
316	struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
317	int ret;
318
319	if (!bb->vm_ops || !bb->vm_ops->migrate)
320		return 0;
321
322	if (!sysfs_get_active(attr_sd))
323		return 0;
324
325	ret = bb->vm_ops->migrate(vma, from, to, flags);
326
327	sysfs_put_active(attr_sd);
328	return ret;
329}
330#endif
331
332static const struct vm_operations_struct bin_vm_ops = {
333	.open		= bin_vma_open,
334	.close		= bin_vma_close,
335	.fault		= bin_fault,
336	.page_mkwrite	= bin_page_mkwrite,
337	.access		= bin_access,
338#ifdef CONFIG_NUMA
339	.set_policy	= bin_set_policy,
340	.get_policy	= bin_get_policy,
341	.migrate	= bin_migrate,
342#endif
343};
344
345static int mmap(struct file *file, struct vm_area_struct *vma)
346{
347	struct bin_buffer *bb = file->private_data;
348	struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
349	struct bin_attribute *attr = attr_sd->s_bin_attr.bin_attr;
350	struct kobject *kobj = attr_sd->s_parent->s_dir.kobj;
351	int rc;
352
353	mutex_lock(&bb->mutex);
354
355	/* need attr_sd for attr, its parent for kobj */
356	rc = -ENODEV;
357	if (!sysfs_get_active(attr_sd))
358		goto out_unlock;
359
360	rc = -EINVAL;
361	if (!attr->mmap)
362		goto out_put;
363
364	rc = attr->mmap(file, kobj, attr, vma);
365	if (rc)
366		goto out_put;
367
368	/*
369	 * PowerPC's pci_mmap of legacy_mem uses shmem_zero_setup()
370	 * to satisfy versions of X which crash if the mmap fails: that
371	 * substitutes a new vm_file, and we don't then want bin_vm_ops.
372	 */
373	if (vma->vm_file != file)
374		goto out_put;
375
376	rc = -EINVAL;
377	if (bb->mmapped && bb->vm_ops != vma->vm_ops)
378		goto out_put;
379
380	rc = 0;
381	bb->mmapped = 1;
382	bb->vm_ops = vma->vm_ops;
383	vma->vm_ops = &bin_vm_ops;
384out_put:
385	sysfs_put_active(attr_sd);
386out_unlock:
387	mutex_unlock(&bb->mutex);
388
389	return rc;
390}
391
392static int open(struct inode * inode, struct file * file)
393{
394	struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
395	struct bin_attribute *attr = attr_sd->s_bin_attr.bin_attr;
396	struct bin_buffer *bb = NULL;
397	int error;
398
399	/* binary file operations requires both @sd and its parent */
400	if (!sysfs_get_active(attr_sd))
401		return -ENODEV;
402
403	error = -EACCES;
404	if ((file->f_mode & FMODE_WRITE) && !(attr->write || attr->mmap))
405		goto err_out;
406	if ((file->f_mode & FMODE_READ) && !(attr->read || attr->mmap))
407		goto err_out;
408
409	error = -ENOMEM;
410	bb = kzalloc(sizeof(*bb), GFP_KERNEL);
411	if (!bb)
412		goto err_out;
413
414	bb->buffer = kmalloc(PAGE_SIZE, GFP_KERNEL);
415	if (!bb->buffer)
416		goto err_out;
417
418	mutex_init(&bb->mutex);
419	bb->file = file;
420	file->private_data = bb;
421
422	mutex_lock(&sysfs_bin_lock);
423	hlist_add_head(&bb->list, &attr_sd->s_bin_attr.buffers);
424	mutex_unlock(&sysfs_bin_lock);
425
426	/* open succeeded, put active references */
427	sysfs_put_active(attr_sd);
428	return 0;
429
430 err_out:
431	sysfs_put_active(attr_sd);
432	kfree(bb);
433	return error;
434}
435
436static int release(struct inode * inode, struct file * file)
437{
438	struct bin_buffer *bb = file->private_data;
439
440	mutex_lock(&sysfs_bin_lock);
441	hlist_del(&bb->list);
442	mutex_unlock(&sysfs_bin_lock);
443
444	kfree(bb->buffer);
445	kfree(bb);
446	return 0;
447}
448
449const struct file_operations bin_fops = {
450	.read		= read,
451	.write		= write,
452	.mmap		= mmap,
453	.llseek		= generic_file_llseek,
454	.open		= open,
455	.release	= release,
456};
457
458
459void unmap_bin_file(struct sysfs_dirent *attr_sd)
460{
461	struct bin_buffer *bb;
462	struct hlist_node *tmp;
463
464	if (sysfs_type(attr_sd) != SYSFS_KOBJ_BIN_ATTR)
465		return;
466
467	mutex_lock(&sysfs_bin_lock);
468
469	hlist_for_each_entry(bb, tmp, &attr_sd->s_bin_attr.buffers, list) {
470		struct inode *inode = bb->file->f_path.dentry->d_inode;
471
472		unmap_mapping_range(inode->i_mapping, 0, 0, 1);
473	}
474
475	mutex_unlock(&sysfs_bin_lock);
476}
477
478/**
479 *	sysfs_create_bin_file - create binary file for object.
480 *	@kobj:	object.
481 *	@attr:	attribute descriptor.
482 */
483
484int sysfs_create_bin_file(struct kobject *kobj,
485			  const struct bin_attribute *attr)
486{
487	BUG_ON(!kobj || !kobj->sd || !attr);
488
489	return sysfs_add_file(kobj->sd, &attr->attr, SYSFS_KOBJ_BIN_ATTR);
490}
491
492
493/**
494 *	sysfs_remove_bin_file - remove binary file for object.
495 *	@kobj:	object.
496 *	@attr:	attribute descriptor.
497 */
498
499void sysfs_remove_bin_file(struct kobject *kobj,
500			   const struct bin_attribute *attr)
501{
502	sysfs_hash_and_remove(kobj->sd, NULL, attr->attr.name);
503}
504
505EXPORT_SYMBOL_GPL(sysfs_create_bin_file);
506EXPORT_SYMBOL_GPL(sysfs_remove_bin_file);
507