Linux kernel mirror (for testing)
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1/*
2 * file.c - part of debugfs, a tiny little debug file system
3 *
4 * Copyright (C) 2004 Greg Kroah-Hartman <greg@kroah.com>
5 * Copyright (C) 2004 IBM Inc.
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License version
9 * 2 as published by the Free Software Foundation.
10 *
11 * debugfs is for people to use instead of /proc or /sys.
12 * See Documentation/DocBook/kernel-api for more details.
13 *
14 */
15
16#include <linux/config.h>
17#include <linux/module.h>
18#include <linux/fs.h>
19#include <linux/pagemap.h>
20#include <linux/debugfs.h>
21
22static ssize_t default_read_file(struct file *file, char __user *buf,
23 size_t count, loff_t *ppos)
24{
25 return 0;
26}
27
28static ssize_t default_write_file(struct file *file, const char __user *buf,
29 size_t count, loff_t *ppos)
30{
31 return count;
32}
33
34static int default_open(struct inode *inode, struct file *file)
35{
36 if (inode->u.generic_ip)
37 file->private_data = inode->u.generic_ip;
38
39 return 0;
40}
41
42struct file_operations debugfs_file_operations = {
43 .read = default_read_file,
44 .write = default_write_file,
45 .open = default_open,
46};
47
48static void debugfs_u8_set(void *data, u64 val)
49{
50 *(u8 *)data = val;
51}
52static u64 debugfs_u8_get(void *data)
53{
54 return *(u8 *)data;
55}
56DEFINE_SIMPLE_ATTRIBUTE(fops_u8, debugfs_u8_get, debugfs_u8_set, "%llu\n");
57
58/**
59 * debugfs_create_u8 - create a file in the debugfs filesystem that is used to read and write a unsigned 8 bit value.
60 *
61 * @name: a pointer to a string containing the name of the file to create.
62 * @mode: the permission that the file should have
63 * @parent: a pointer to the parent dentry for this file. This should be a
64 * directory dentry if set. If this paramater is NULL, then the
65 * file will be created in the root of the debugfs filesystem.
66 * @value: a pointer to the variable that the file should read to and write
67 * from.
68 *
69 * This function creates a file in debugfs with the given name that
70 * contains the value of the variable @value. If the @mode variable is so
71 * set, it can be read from, and written to.
72 *
73 * This function will return a pointer to a dentry if it succeeds. This
74 * pointer must be passed to the debugfs_remove() function when the file is
75 * to be removed (no automatic cleanup happens if your module is unloaded,
76 * you are responsible here.) If an error occurs, NULL will be returned.
77 *
78 * If debugfs is not enabled in the kernel, the value -ENODEV will be
79 * returned. It is not wise to check for this value, but rather, check for
80 * NULL or !NULL instead as to eliminate the need for #ifdef in the calling
81 * code.
82 */
83struct dentry *debugfs_create_u8(const char *name, mode_t mode,
84 struct dentry *parent, u8 *value)
85{
86 return debugfs_create_file(name, mode, parent, value, &fops_u8);
87}
88EXPORT_SYMBOL_GPL(debugfs_create_u8);
89
90static void debugfs_u16_set(void *data, u64 val)
91{
92 *(u16 *)data = val;
93}
94static u64 debugfs_u16_get(void *data)
95{
96 return *(u16 *)data;
97}
98DEFINE_SIMPLE_ATTRIBUTE(fops_u16, debugfs_u16_get, debugfs_u16_set, "%llu\n");
99
100/**
101 * debugfs_create_u16 - create a file in the debugfs filesystem that is used to read and write a unsigned 8 bit value.
102 *
103 * @name: a pointer to a string containing the name of the file to create.
104 * @mode: the permission that the file should have
105 * @parent: a pointer to the parent dentry for this file. This should be a
106 * directory dentry if set. If this paramater is NULL, then the
107 * file will be created in the root of the debugfs filesystem.
108 * @value: a pointer to the variable that the file should read to and write
109 * from.
110 *
111 * This function creates a file in debugfs with the given name that
112 * contains the value of the variable @value. If the @mode variable is so
113 * set, it can be read from, and written to.
114 *
115 * This function will return a pointer to a dentry if it succeeds. This
116 * pointer must be passed to the debugfs_remove() function when the file is
117 * to be removed (no automatic cleanup happens if your module is unloaded,
118 * you are responsible here.) If an error occurs, NULL will be returned.
119 *
120 * If debugfs is not enabled in the kernel, the value -ENODEV will be
121 * returned. It is not wise to check for this value, but rather, check for
122 * NULL or !NULL instead as to eliminate the need for #ifdef in the calling
123 * code.
124 */
125struct dentry *debugfs_create_u16(const char *name, mode_t mode,
126 struct dentry *parent, u16 *value)
127{
128 return debugfs_create_file(name, mode, parent, value, &fops_u16);
129}
130EXPORT_SYMBOL_GPL(debugfs_create_u16);
131
132static void debugfs_u32_set(void *data, u64 val)
133{
134 *(u32 *)data = val;
135}
136static u64 debugfs_u32_get(void *data)
137{
138 return *(u32 *)data;
139}
140DEFINE_SIMPLE_ATTRIBUTE(fops_u32, debugfs_u32_get, debugfs_u32_set, "%llu\n");
141
142/**
143 * debugfs_create_u32 - create a file in the debugfs filesystem that is used to read and write a unsigned 8 bit value.
144 *
145 * @name: a pointer to a string containing the name of the file to create.
146 * @mode: the permission that the file should have
147 * @parent: a pointer to the parent dentry for this file. This should be a
148 * directory dentry if set. If this paramater is NULL, then the
149 * file will be created in the root of the debugfs filesystem.
150 * @value: a pointer to the variable that the file should read to and write
151 * from.
152 *
153 * This function creates a file in debugfs with the given name that
154 * contains the value of the variable @value. If the @mode variable is so
155 * set, it can be read from, and written to.
156 *
157 * This function will return a pointer to a dentry if it succeeds. This
158 * pointer must be passed to the debugfs_remove() function when the file is
159 * to be removed (no automatic cleanup happens if your module is unloaded,
160 * you are responsible here.) If an error occurs, NULL will be returned.
161 *
162 * If debugfs is not enabled in the kernel, the value -ENODEV will be
163 * returned. It is not wise to check for this value, but rather, check for
164 * NULL or !NULL instead as to eliminate the need for #ifdef in the calling
165 * code.
166 */
167struct dentry *debugfs_create_u32(const char *name, mode_t mode,
168 struct dentry *parent, u32 *value)
169{
170 return debugfs_create_file(name, mode, parent, value, &fops_u32);
171}
172EXPORT_SYMBOL_GPL(debugfs_create_u32);
173
174static ssize_t read_file_bool(struct file *file, char __user *user_buf,
175 size_t count, loff_t *ppos)
176{
177 char buf[3];
178 u32 *val = file->private_data;
179
180 if (*val)
181 buf[0] = 'Y';
182 else
183 buf[0] = 'N';
184 buf[1] = '\n';
185 buf[2] = 0x00;
186 return simple_read_from_buffer(user_buf, count, ppos, buf, 2);
187}
188
189static ssize_t write_file_bool(struct file *file, const char __user *user_buf,
190 size_t count, loff_t *ppos)
191{
192 char buf[32];
193 int buf_size;
194 u32 *val = file->private_data;
195
196 buf_size = min(count, (sizeof(buf)-1));
197 if (copy_from_user(buf, user_buf, buf_size))
198 return -EFAULT;
199
200 switch (buf[0]) {
201 case 'y':
202 case 'Y':
203 case '1':
204 *val = 1;
205 break;
206 case 'n':
207 case 'N':
208 case '0':
209 *val = 0;
210 break;
211 }
212
213 return count;
214}
215
216static struct file_operations fops_bool = {
217 .read = read_file_bool,
218 .write = write_file_bool,
219 .open = default_open,
220};
221
222/**
223 * debugfs_create_bool - create a file in the debugfs filesystem that is used to read and write a boolean value.
224 *
225 * @name: a pointer to a string containing the name of the file to create.
226 * @mode: the permission that the file should have
227 * @parent: a pointer to the parent dentry for this file. This should be a
228 * directory dentry if set. If this paramater is NULL, then the
229 * file will be created in the root of the debugfs filesystem.
230 * @value: a pointer to the variable that the file should read to and write
231 * from.
232 *
233 * This function creates a file in debugfs with the given name that
234 * contains the value of the variable @value. If the @mode variable is so
235 * set, it can be read from, and written to.
236 *
237 * This function will return a pointer to a dentry if it succeeds. This
238 * pointer must be passed to the debugfs_remove() function when the file is
239 * to be removed (no automatic cleanup happens if your module is unloaded,
240 * you are responsible here.) If an error occurs, NULL will be returned.
241 *
242 * If debugfs is not enabled in the kernel, the value -ENODEV will be
243 * returned. It is not wise to check for this value, but rather, check for
244 * NULL or !NULL instead as to eliminate the need for #ifdef in the calling
245 * code.
246 */
247struct dentry *debugfs_create_bool(const char *name, mode_t mode,
248 struct dentry *parent, u32 *value)
249{
250 return debugfs_create_file(name, mode, parent, value, &fops_bool);
251}
252EXPORT_SYMBOL_GPL(debugfs_create_bool);
253