aboutsummaryrefslogtreecommitdiff
path: root/fs/sysfs/bin.c
blob: 2ce9a5db6ab59b5fee35a46503b5ac90d9013356 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
/*
 * fs/sysfs/bin.c - sysfs binary file implementation
 *
 * Copyright (c) 2003 Patrick Mochel
 * Copyright (c) 2003 Matthew Wilcox
 * Copyright (c) 2004 Silicon Graphics, Inc.
 * Copyright (c) 2007 SUSE Linux Products GmbH
 * Copyright (c) 2007 Tejun Heo <teheo@suse.de>
 *
 * This file is released under the GPLv2.
 *
 * Please see Documentation/filesystems/sysfs.txt for more information.
 */

#undef DEBUG

#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/kernel.h>
#include <linux/kobject.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/mutex.h>
#include <linux/mm.h>

#include <asm/uaccess.h>

#include "sysfs.h"

/*
 * There's one bin_buffer for each open file.
 *
 * filp->private_data points to bin_buffer and
 * sysfs_dirent->s_bin_attr.buffers points to a the bin_buffer s
 * sysfs_dirent->s_bin_attr.buffers is protected by sysfs_bin_lock
 */
static DEFINE_MUTEX(sysfs_bin_lock);

struct bin_buffer {
	struct mutex			mutex;
	void				*buffer;
	int				mmapped;
	const struct vm_operations_struct *vm_ops;
	struct file			*file;
	struct hlist_node		list;
};

static int
fill_read(struct file *file, char *buffer, loff_t off, size_t count)
{
	struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
	struct bin_attribute *attr = attr_sd->s_bin_attr.bin_attr;
	struct kobject *kobj = attr_sd->s_parent->s_dir.kobj;
	int rc;

	/* need attr_sd for attr, its parent for kobj */
	if (!sysfs_get_active(attr_sd))
		return -ENODEV;

	rc = -EIO;
	if (attr->read)
		rc = attr->read(file, kobj, attr, buffer, off, count);

	sysfs_put_active(attr_sd);

	return rc;
}

static ssize_t
read(struct file *file, char __user *userbuf, size_t bytes, loff_t *off)
{
	struct bin_buffer *bb = file->private_data;
	int size = file_inode(file)->i_size;
	loff_t offs = *off;
	int count = min_t(size_t, bytes, PAGE_SIZE);
	char *temp;

	if (!bytes)
		return 0;

	if (size) {
		if (offs > size)
			return 0;
		if (offs + count > size)
			count = size - offs;
	}

	temp = kmalloc(count, GFP_KERNEL);
	if (!temp)
		return -ENOMEM;

	mutex_lock(&bb->mutex);

	count = fill_read(file, bb->buffer, offs, count);
	if (count < 0) {
		mutex_unlock(&bb->mutex);
		goto out_free;
	}

	memcpy(temp, bb->buffer, count);

	mutex_unlock(&bb->mutex);

	if (copy_to_user(userbuf, temp, count)) {
		count = -EFAULT;
		goto out_free;
	}

	pr_debug("offs = %lld, *off = %lld, count = %d\n", offs, *off, count);

	*off = offs + count;

 out_free:
	kfree(temp);
	return count;
}

static int
flush_write(struct file *file, char *buffer, loff_t offset, size_t count)
{
	struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
	struct bin_attribute *attr = attr_sd->s_bin_attr.bin_attr;
	struct kobject *kobj = attr_sd->s_parent->s_dir.kobj;
	int rc;

	/* need attr_sd for attr, its parent for kobj */
	if (!sysfs_get_active(attr_sd))
		return -ENODEV;

	rc = -EIO;
	if (attr->write)
		rc = attr->write(file, kobj, attr, buffer, offset, count);

	sysfs_put_active(attr_sd);

	return rc;
}

static ssize_t write(struct file *file, const char __user *userbuf,
		     size_t bytes, loff_t *off)
{
	struct bin_buffer *bb = file->private_data;
	int size = file_inode(file)->i_size;
	loff_t offs = *off;
	int count = min_t(size_t, bytes, PAGE_SIZE);
	char *temp;

	if (!bytes)
		return 0;

	if (size) {
		if (offs > size)
			return 0;
		if (offs + count > size)
			count = size - offs;
	}

	temp = memdup_user(userbuf, count);
	if (IS_ERR(temp))
		return PTR_ERR(temp);

	mutex_lock(&bb->mutex);

	memcpy(bb->buffer, temp, count);

	count = flush_write(file, bb->buffer, offs, count);
	mutex_unlock(&bb->mutex);

	if (count > 0)
		*off = offs + count;

	kfree(temp);
	return count;
}

static void bin_vma_open(struct vm_area_struct *vma)
{
	struct file *file = vma->vm_file;
	struct bin_buffer *bb = file->private_data;
	struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;

	if (!bb->vm_ops)
		return;

	if (!sysfs_get_active(attr_sd))
		return;

	if (bb->vm_ops->open)
		bb->vm_ops->open(vma);

	sysfs_put_active(attr_sd);
}

static int bin_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
{
	struct file *file = vma->vm_file;
	struct bin_buffer *bb = file->private_data;
	struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
	int ret;

	if (!bb->vm_ops)
		return VM_FAULT_SIGBUS;

	if (!sysfs_get_active(attr_sd))
		return VM_FAULT_SIGBUS;

	ret = VM_FAULT_SIGBUS;
	if (bb->vm_ops->fault)
		ret = bb->vm_ops->fault(vma, vmf);

	sysfs_put_active(attr_sd);
	return ret;
}

static int bin_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
{
	struct file *file = vma->vm_file;
	struct bin_buffer *bb = file->private_data;
	struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
	int ret;

	if (!bb->vm_ops)
		return VM_FAULT_SIGBUS;

	if (!sysfs_get_active(attr_sd))
		return VM_FAULT_SIGBUS;

	ret = 0;
	if (bb->vm_ops->page_mkwrite)
		ret = bb->vm_ops->page_mkwrite(vma, vmf);
	else
		file_update_time(file);

	sysfs_put_active(attr_sd);
	return ret;
}

static int bin_access(struct vm_area_struct *vma, unsigned long addr,
		  void *buf, int len, int write)
{
	struct file *file = vma->vm_file;
	struct bin_buffer *bb = file->private_data;
	struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
	int ret;

	if (!bb->vm_ops)
		return -EINVAL;

	if (!sysfs_get_active(attr_sd))
		return -EINVAL;

	ret = -EINVAL;
	if (bb->vm_ops->access)
		ret = bb->vm_ops->access(vma, addr, buf, len, write);

	sysfs_put_active(attr_sd);
	return ret;
}

#ifdef CONFIG_NUMA
static int bin_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
{
	struct file *file = vma->vm_file;
	struct bin_buffer *bb = file->private_data;
	struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
	int ret;

	if (!bb->vm_ops)
		return 0;

	if (!sysfs_get_active(attr_sd))
		return -EINVAL;

	ret = 0;
	if (bb->vm_ops->set_policy)
		ret = bb->vm_ops->set_policy(vma, new);

	sysfs_put_active(attr_sd);
	return ret;
}

static struct mempolicy *bin_get_policy(struct vm_area_struct *vma,
					unsigned long addr)
{
	struct file *file = vma->vm_file;
	struct bin_buffer *bb = file->private_data;
	struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
	struct mempolicy *pol;

	if (!bb->vm_ops)
		return vma->vm_policy;

	if (!sysfs_get_active(attr_sd))
		return vma->vm_policy;

	pol = vma->vm_policy;
	if (bb->vm_ops->get_policy)
		pol = bb->vm_ops->get_policy(vma, addr);

	sysfs_put_active(attr_sd);
	return pol;
}

static int bin_migrate(struct vm_area_struct *vma, const nodemask_t *from,
			const nodemask_t *to, unsigned long flags)
{
	struct file *file = vma->vm_file;
	struct bin_buffer *bb = file->private_data;
	struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
	int ret;

	if (!bb->vm_ops)
		return 0;

	if (!sysfs_get_active(attr_sd))
		return 0;

	ret = 0;
	if (bb->vm_ops->migrate)
		ret = bb->vm_ops->migrate(vma, from, to, flags);

	sysfs_put_active(attr_sd);
	return ret;
}
#endif

static const struct vm_operations_struct bin_vm_ops = {
	.open		= bin_vma_open,
	.fault		= bin_fault,
	.page_mkwrite	= bin_page_mkwrite,
	.access		= bin_access,
#ifdef CONFIG_NUMA
	.set_policy	= bin_set_policy,
	.get_policy	= bin_get_policy,
	.migrate	= bin_migrate,
#endif
};

static int mmap(struct file *file, struct vm_area_struct *vma)
{
	struct bin_buffer *bb = file->private_data;
	struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
	struct bin_attribute *attr = attr_sd->s_bin_attr.bin_attr;
	struct kobject *kobj = attr_sd->s_parent->s_dir.kobj;
	int rc;

	mutex_lock(&bb->mutex);

	/* need attr_sd for attr, its parent for kobj */
	rc = -ENODEV;
	if (!sysfs_get_active(attr_sd))
		goto out_unlock;

	rc = -EINVAL;
	if (!attr->mmap)
		goto out_put;

	rc = attr->mmap(file, kobj, attr, vma);
	if (rc)
		goto out_put;

	/*
	 * PowerPC's pci_mmap of legacy_mem uses shmem_zero_setup()
	 * to satisfy versions of X which crash if the mmap fails: that
	 * substitutes a new vm_file, and we don't then want bin_vm_ops.
	 */
	if (vma->vm_file != file)
		goto out_put;

	rc = -EINVAL;
	if (bb->mmapped && bb->vm_ops != vma->vm_ops)
		goto out_put;

	/*
	 * It is not possible to successfully wrap close.
	 * So error if someone is trying to use close.
	 */
	rc = -EINVAL;
	if (vma->vm_ops && vma->vm_ops->close)
		goto out_put;

	rc = 0;
	bb->mmapped = 1;
	bb->vm_ops = vma->vm_ops;
	vma->vm_ops = &bin_vm_ops;
out_put:
	sysfs_put_active(attr_sd);
out_unlock:
	mutex_unlock(&bb->mutex);

	return rc;
}

static int open(struct inode * inode, struct file * file)
{
	struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
	struct bin_attribute *attr = attr_sd->s_bin_attr.bin_attr;
	struct bin_buffer *bb = NULL;
	int error;

	/* binary file operations requires both @sd and its parent */
	if (!sysfs_get_active(attr_sd))
		return -ENODEV;

	error = -EACCES;
	if ((file->f_mode & FMODE_WRITE) && !(attr->write || attr->mmap))
		goto err_out;
	if ((file->f_mode & FMODE_READ) && !(attr->read || attr->mmap))
		goto err_out;

	error = -ENOMEM;
	bb = kzalloc(sizeof(*bb), GFP_KERNEL);
	if (!bb)
		goto err_out;

	bb->buffer = kmalloc(PAGE_SIZE, GFP_KERNEL);
	if (!bb->buffer)
		goto err_out;

	mutex_init(&bb->mutex);
	bb->file = file;
	file->private_data = bb;

	mutex_lock(&sysfs_bin_lock);
	hlist_add_head(&bb->list, &attr_sd->s_bin_attr.buffers);
	mutex_unlock(&sysfs_bin_lock);

	/* open succeeded, put active references */
	sysfs_put_active(attr_sd);
	return 0;

 err_out:
	sysfs_put_active(attr_sd);
	kfree(bb);
	return error;
}

static int release(struct inode * inode, struct file * file)
{
	struct bin_buffer *bb = file->private_data;

	mutex_lock(&sysfs_bin_lock);
	hlist_del(&bb->list);
	mutex_unlock(&sysfs_bin_lock);

	kfree(bb->buffer);
	kfree(bb);
	return 0;
}

const struct file_operations bin_fops = {
	.read		= read,
	.write		= write,
	.mmap		= mmap,
	.llseek		= generic_file_llseek,
	.open		= open,
	.release	= release,
};


void unmap_bin_file(struct sysfs_dirent *attr_sd)
{
	struct bin_buffer *bb;
	struct hlist_node *tmp;

	if (sysfs_type(attr_sd) != SYSFS_KOBJ_BIN_ATTR)
		return;

	mutex_lock(&sysfs_bin_lock);

	hlist_for_each_entry(bb, tmp, &attr_sd->s_bin_attr.buffers, list) {
		struct inode *inode = file_inode(bb->file);

		unmap_mapping_range(inode->i_mapping, 0, 0, 1);
	}

	mutex_unlock(&sysfs_bin_lock);
}

/**
 *	sysfs_create_bin_file - create binary file for object.
 *	@kobj:	object.
 *	@attr:	attribute descriptor.
 */

int sysfs_create_bin_file(struct kobject *kobj,
			  const struct bin_attribute *attr)
{
	BUG_ON(!kobj || !kobj->sd || !attr);

	return sysfs_add_file(kobj->sd, &attr->attr, SYSFS_KOBJ_BIN_ATTR);
}


/**
 *	sysfs_remove_bin_file - remove binary file for object.
 *	@kobj:	object.
 *	@attr:	attribute descriptor.
 */

void sysfs_remove_bin_file(struct kobject *kobj,
			   const struct bin_attribute *attr)
{
	sysfs_hash_and_remove(kobj->sd, NULL, attr->attr.name);
}

EXPORT_SYMBOL_GPL(sysfs_create_bin_file);
EXPORT_SYMBOL_GPL(sysfs_remove_bin_file);