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