Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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kernel
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linux
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/kobject.h>
14#include <linux/module.h>
15#include <linux/slab.h>
16
17#include <asm/uaccess.h>
18
19#include "sysfs.h"
20
21static int
22fill_read(struct dentry *dentry, char *buffer, loff_t off, size_t count)
23{
24 struct bin_attribute * attr = to_bin_attr(dentry);
25 struct kobject * kobj = to_kobj(dentry->d_parent);
26
27 if (!attr->read)
28 return -EIO;
29
30 return attr->read(kobj, buffer, off, count);
31}
32
33static ssize_t
34read(struct file * file, char __user * userbuf, size_t count, loff_t * off)
35{
36 char *buffer = file->private_data;
37 struct dentry *dentry = file->f_dentry;
38 int size = dentry->d_inode->i_size;
39 loff_t offs = *off;
40 int ret;
41
42 if (count > PAGE_SIZE)
43 count = PAGE_SIZE;
44
45 if (size) {
46 if (offs > size)
47 return 0;
48 if (offs + count > size)
49 count = size - offs;
50 }
51
52 ret = fill_read(dentry, buffer, offs, count);
53 if (ret < 0)
54 return ret;
55 count = ret;
56
57 if (copy_to_user(userbuf, buffer, count))
58 return -EFAULT;
59
60 pr_debug("offs = %lld, *off = %lld, count = %zd\n", offs, *off, count);
61
62 *off = offs + count;
63
64 return count;
65}
66
67static int
68flush_write(struct dentry *dentry, char *buffer, loff_t offset, size_t count)
69{
70 struct bin_attribute *attr = to_bin_attr(dentry);
71 struct kobject *kobj = to_kobj(dentry->d_parent);
72
73 if (!attr->write)
74 return -EIO;
75
76 return attr->write(kobj, buffer, offset, count);
77}
78
79static ssize_t write(struct file * file, const char __user * userbuf,
80 size_t count, loff_t * off)
81{
82 char *buffer = file->private_data;
83 struct dentry *dentry = file->f_dentry;
84 int size = dentry->d_inode->i_size;
85 loff_t offs = *off;
86
87 if (count > PAGE_SIZE)
88 count = PAGE_SIZE;
89 if (size) {
90 if (offs > size)
91 return 0;
92 if (offs + count > size)
93 count = size - offs;
94 }
95
96 if (copy_from_user(buffer, userbuf, count))
97 return -EFAULT;
98
99 count = flush_write(dentry, buffer, offs, count);
100 if (count > 0)
101 *off = offs + count;
102 return count;
103}
104
105static int mmap(struct file *file, struct vm_area_struct *vma)
106{
107 struct dentry *dentry = file->f_dentry;
108 struct bin_attribute *attr = to_bin_attr(dentry);
109 struct kobject *kobj = to_kobj(dentry->d_parent);
110
111 if (!attr->mmap)
112 return -EINVAL;
113
114 return attr->mmap(kobj, attr, vma);
115}
116
117static int open(struct inode * inode, struct file * file)
118{
119 struct kobject *kobj = sysfs_get_kobject(file->f_dentry->d_parent);
120 struct bin_attribute * attr = to_bin_attr(file->f_dentry);
121 int error = -EINVAL;
122
123 if (!kobj || !attr)
124 goto Done;
125
126 /* Grab the module reference for this attribute if we have one */
127 error = -ENODEV;
128 if (!try_module_get(attr->attr.owner))
129 goto Done;
130
131 error = -EACCES;
132 if ((file->f_mode & FMODE_WRITE) && !(attr->write || attr->mmap))
133 goto Error;
134 if ((file->f_mode & FMODE_READ) && !(attr->read || attr->mmap))
135 goto Error;
136
137 error = -ENOMEM;
138 file->private_data = kmalloc(PAGE_SIZE, GFP_KERNEL);
139 if (!file->private_data)
140 goto Error;
141
142 error = 0;
143 goto Done;
144
145 Error:
146 module_put(attr->attr.owner);
147 Done:
148 if (error && kobj)
149 kobject_put(kobj);
150 return error;
151}
152
153static int release(struct inode * inode, struct file * file)
154{
155 struct kobject * kobj = to_kobj(file->f_dentry->d_parent);
156 struct bin_attribute * attr = to_bin_attr(file->f_dentry);
157 u8 * buffer = file->private_data;
158
159 if (kobj)
160 kobject_put(kobj);
161 module_put(attr->attr.owner);
162 kfree(buffer);
163 return 0;
164}
165
166struct file_operations bin_fops = {
167 .read = read,
168 .write = write,
169 .mmap = mmap,
170 .llseek = generic_file_llseek,
171 .open = open,
172 .release = release,
173};
174
175/**
176 * sysfs_create_bin_file - create binary file for object.
177 * @kobj: object.
178 * @attr: attribute descriptor.
179 *
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 */
196
197int sysfs_remove_bin_file(struct kobject * kobj, struct bin_attribute * attr)
198{
199 sysfs_hash_and_remove(kobj->dentry,attr->attr.name);
200 return 0;
201}
202
203EXPORT_SYMBOL_GPL(sysfs_create_bin_file);
204EXPORT_SYMBOL_GPL(sysfs_remove_bin_file);