1/*
2 * bin.c - binary file operations for sysfs.
3 *
4 * Copyright (c) 2003 Patrick Mochel
5 * Copyright (c) 2003 Matthew Wilcox
6 * Copyright (c) 2004 Silicon Graphics, Inc.
7 */
8
9#undef DEBUG
10
11#include <linux/errno.h>
12#include <linux/fs.h>
13#include <linux/kernel.h>
14#include <linux/kobject.h>
15#include <linux/module.h>
16#include <linux/slab.h>
17
18#include <asm/uaccess.h>
19#include <asm/semaphore.h>
20
21#include "sysfs.h"
22
23static int
24fill_read(struct dentry *dentry, char *buffer, loff_t off, size_t count)
25{
26	struct bin_attribute * attr = to_bin_attr(dentry);
27	struct kobject * kobj = to_kobj(dentry->d_parent);
28
29	if (!attr->read)
30		return -EIO;
31
32	return attr->read(kobj, buffer, off, count);
33}
34
35static ssize_t
36read(struct file * file, char __user * userbuf, size_t count, loff_t * off)
37{
38	char *buffer = file->private_data;
39	struct dentry *dentry = file->f_path.dentry;
40	int size = dentry->d_inode->i_size;
41	loff_t offs = *off;
42	int ret;
43
44	if (count > PAGE_SIZE)
45		count = PAGE_SIZE;
46
47	if (size) {
48		if (offs > size)
49			return 0;
50		if (offs + count > size)
51			count = size - offs;
52	}
53
54	ret = fill_read(dentry, buffer, offs, count);
55	if (ret < 0)
56		return ret;
57	count = ret;
58
59	if (copy_to_user(userbuf, buffer, count))
60		return -EFAULT;
61
62	pr_debug("offs = %lld, *off = %lld, count = %zd\n", offs, *off, count);
63
64	*off = offs + count;
65
66	return count;
67}
68
69static int
70flush_write(struct dentry *dentry, char *buffer, loff_t offset, size_t count)
71{
72	struct bin_attribute *attr = to_bin_attr(dentry);
73	struct kobject *kobj = to_kobj(dentry->d_parent);
74
75	if (!attr->write)
76		return -EIO;
77
78	return attr->write(kobj, buffer, offset, count);
79}
80
81static ssize_t write(struct file * file, const char __user * userbuf,
82		     size_t count, loff_t * off)
83{
84	char *buffer = file->private_data;
85	struct dentry *dentry = file->f_path.dentry;
86	int size = dentry->d_inode->i_size;
87	loff_t offs = *off;
88
89	if (count > PAGE_SIZE)
90		count = PAGE_SIZE;
91	if (size) {
92		if (offs > size)
93			return 0;
94		if (offs + count > size)
95			count = size - offs;
96	}
97
98	if (copy_from_user(buffer, userbuf, count))
99		return -EFAULT;
100
101	count = flush_write(dentry, buffer, offs, count);
102	if (count > 0)
103		*off = offs + count;
104	return count;
105}
106
107static int mmap(struct file *file, struct vm_area_struct *vma)
108{
109	struct dentry *dentry = file->f_path.dentry;
110	struct bin_attribute *attr = to_bin_attr(dentry);
111	struct kobject *kobj = to_kobj(dentry->d_parent);
112
113	if (!attr->mmap)
114		return -EINVAL;
115
116	return attr->mmap(kobj, attr, vma);
117}
118
119static int open(struct inode * inode, struct file * file)
120{
121	struct kobject *kobj = sysfs_get_kobject(file->f_path.dentry->d_parent);
122	struct bin_attribute * attr = to_bin_attr(file->f_path.dentry);
123	int error = -EINVAL;
124
125	if (!kobj || !attr)
126		goto Done;
127
128	/* Grab the module reference for this attribute if we have one */
129	error = -ENODEV;
130	if (!try_module_get(attr->attr.owner))
131		goto Done;
132
133	error = -EACCES;
134	if ((file->f_mode & FMODE_WRITE) && !(attr->write || attr->mmap))
135		goto Error;
136	if ((file->f_mode & FMODE_READ) && !(attr->read || attr->mmap))
137		goto Error;
138
139	error = -ENOMEM;
140	file->private_data = kmalloc(PAGE_SIZE, GFP_KERNEL);
141	if (!file->private_data)
142		goto Error;
143
144	error = 0;
145    goto Done;
146
147 Error:
148	module_put(attr->attr.owner);
149 Done:
150	if (error)
151		kobject_put(kobj);
152	return error;
153}
154
155static int release(struct inode * inode, struct file * file)
156{
157	struct kobject * kobj = to_kobj(file->f_path.dentry->d_parent);
158	struct bin_attribute * attr = to_bin_attr(file->f_path.dentry);
159	u8 * buffer = file->private_data;
160
161	kobject_put(kobj);
162	module_put(attr->attr.owner);
163	kfree(buffer);
164	return 0;
165}
166
167const struct file_operations bin_fops = {
168	.read		= read,
169	.write		= write,
170	.mmap		= mmap,
171	.llseek		= generic_file_llseek,
172	.open		= open,
173	.release	= release,
174};
175
176/**
177 *	sysfs_create_bin_file - create binary file for object.
178 *	@kobj:	object.
179 *	@attr:	attribute descriptor.
180 */
181
182int sysfs_create_bin_file(struct kobject * kobj, struct bin_attribute * attr)
183{
184	BUG_ON(!kobj || !kobj->dentry || !attr);
185
186	return sysfs_add_file(kobj->dentry, &attr->attr, SYSFS_KOBJ_BIN_ATTR);
187}
188
189
190/**
191 *	sysfs_remove_bin_file - remove binary file for object.
192 *	@kobj:	object.
193 *	@attr:	attribute descriptor.
194 */
195
196void sysfs_remove_bin_file(struct kobject * kobj, struct bin_attribute * attr)
197{
198	if (sysfs_hash_and_remove(kobj->dentry, attr->attr.name) < 0) {
199		printk(KERN_ERR "%s: "
200			"bad dentry or inode or no such file: \"%s\"\n",
201			__FUNCTION__, attr->attr.name);
202		dump_stack();
203	}
204}
205
206EXPORT_SYMBOL_GPL(sysfs_create_bin_file);
207EXPORT_SYMBOL_GPL(sysfs_remove_bin_file);
208