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)
183		return;
184
185	if (!sysfs_get_active(attr_sd))
186		return;
187
188	if (bb->vm_ops->open)
189		bb->vm_ops->open(vma);
190
191	sysfs_put_active(attr_sd);
192}
193
194static int bin_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
195{
196	struct file *file = vma->vm_file;
197	struct bin_buffer *bb = file->private_data;
198	struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
199	int ret;
200
201	if (!bb->vm_ops)
202		return VM_FAULT_SIGBUS;
203
204	if (!sysfs_get_active(attr_sd))
205		return VM_FAULT_SIGBUS;
206
207	ret = VM_FAULT_SIGBUS;
208	if (bb->vm_ops->fault)
209		ret = bb->vm_ops->fault(vma, vmf);
210
211	sysfs_put_active(attr_sd);
212	return ret;
213}
214
215static int bin_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
216{
217	struct file *file = vma->vm_file;
218	struct bin_buffer *bb = file->private_data;
219	struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
220	int ret;
221
222	if (!bb->vm_ops)
223		return VM_FAULT_SIGBUS;
224
225	if (!sysfs_get_active(attr_sd))
226		return VM_FAULT_SIGBUS;
227
228	ret = 0;
229	if (bb->vm_ops->page_mkwrite)
230		ret = bb->vm_ops->page_mkwrite(vma, vmf);
231
232	sysfs_put_active(attr_sd);
233	return ret;
234}
235
236static int bin_access(struct vm_area_struct *vma, unsigned long addr,
237		  void *buf, int len, int write)
238{
239	struct file *file = vma->vm_file;
240	struct bin_buffer *bb = file->private_data;
241	struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
242	int ret;
243
244	if (!bb->vm_ops)
245		return -EINVAL;
246
247	if (!sysfs_get_active(attr_sd))
248		return -EINVAL;
249
250	ret = -EINVAL;
251	if (bb->vm_ops->access)
252		ret = bb->vm_ops->access(vma, addr, buf, len, write);
253
254	sysfs_put_active(attr_sd);
255	return ret;
256}
257
258#ifdef CONFIG_NUMA
259static int bin_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
260{
261	struct file *file = vma->vm_file;
262	struct bin_buffer *bb = file->private_data;
263	struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
264	int ret;
265
266	if (!bb->vm_ops)
267		return 0;
268
269	if (!sysfs_get_active(attr_sd))
270		return -EINVAL;
271
272	ret = 0;
273	if (bb->vm_ops->set_policy)
274		ret = bb->vm_ops->set_policy(vma, new);
275
276	sysfs_put_active(attr_sd);
277	return ret;
278}
279
280static struct mempolicy *bin_get_policy(struct vm_area_struct *vma,
281					unsigned long addr)
282{
283	struct file *file = vma->vm_file;
284	struct bin_buffer *bb = file->private_data;
285	struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
286	struct mempolicy *pol;
287
288	if (!bb->vm_ops)
289		return vma->vm_policy;
290
291	if (!sysfs_get_active(attr_sd))
292		return vma->vm_policy;
293
294	pol = vma->vm_policy;
295	if (bb->vm_ops->get_policy)
296		pol = bb->vm_ops->get_policy(vma, addr);
297
298	sysfs_put_active(attr_sd);
299	return pol;
300}
301
302static int bin_migrate(struct vm_area_struct *vma, const nodemask_t *from,
303			const nodemask_t *to, unsigned long flags)
304{
305	struct file *file = vma->vm_file;
306	struct bin_buffer *bb = file->private_data;
307	struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
308	int ret;
309
310	if (!bb->vm_ops)
311		return 0;
312
313	if (!sysfs_get_active(attr_sd))
314		return 0;
315
316	ret = 0;
317	if (bb->vm_ops->migrate)
318		ret = bb->vm_ops->migrate(vma, from, to, flags);
319
320	sysfs_put_active(attr_sd);
321	return ret;
322}
323#endif
324
325static const struct vm_operations_struct bin_vm_ops = {
326	.open		= bin_vma_open,
327	.fault		= bin_fault,
328	.page_mkwrite	= bin_page_mkwrite,
329	.access		= bin_access,
330#ifdef CONFIG_NUMA
331	.set_policy	= bin_set_policy,
332	.get_policy	= bin_get_policy,
333	.migrate	= bin_migrate,
334#endif
335};
336
337static int mmap(struct file *file, struct vm_area_struct *vma)
338{
339	struct bin_buffer *bb = file->private_data;
340	struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
341	struct bin_attribute *attr = attr_sd->s_bin_attr.bin_attr;
342	struct kobject *kobj = attr_sd->s_parent->s_dir.kobj;
343	int rc;
344
345	mutex_lock(&bb->mutex);
346
347	/* need attr_sd for attr, its parent for kobj */
348	rc = -ENODEV;
349	if (!sysfs_get_active(attr_sd))
350		goto out_unlock;
351
352	rc = -EINVAL;
353	if (!attr->mmap)
354		goto out_put;
355
356	rc = attr->mmap(file, kobj, attr, vma);
357	if (rc)
358		goto out_put;
359
360	/*
361	 * PowerPC's pci_mmap of legacy_mem uses shmem_zero_setup()
362	 * to satisfy versions of X which crash if the mmap fails: that
363	 * substitutes a new vm_file, and we don't then want bin_vm_ops.
364	 */
365	if (vma->vm_file != file)
366		goto out_put;
367
368	rc = -EINVAL;
369	if (bb->mmapped && bb->vm_ops != vma->vm_ops)
370		goto out_put;
371
372	/*
373	 * It is not possible to successfully wrap close.
374	 * So error if someone is trying to use close.
375	 */
376	rc = -EINVAL;
377	if (vma->vm_ops && vma->vm_ops->close)
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);