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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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
Linus Torvalds1da177e2005-04-16 15:20:36 -070016#include <linux/module.h>
17#include <linux/fs.h>
18#include <linux/pagemap.h>
19#include <linux/debugfs.h>
20
21static ssize_t default_read_file(struct file *file, char __user *buf,
22 size_t count, loff_t *ppos)
23{
24 return 0;
25}
26
27static ssize_t default_write_file(struct file *file, const char __user *buf,
28 size_t count, loff_t *ppos)
29{
30 return count;
31}
32
33static int default_open(struct inode *inode, struct file *file)
34{
Theodore Ts'o8e18e292006-09-27 01:50:46 -070035 if (inode->i_private)
36 file->private_data = inode->i_private;
Linus Torvalds1da177e2005-04-16 15:20:36 -070037
38 return 0;
39}
40
Arjan van de Ven4b6f5d22006-03-28 01:56:42 -080041const struct file_operations debugfs_file_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -070042 .read = default_read_file,
43 .write = default_write_file,
44 .open = default_open,
45};
46
Arnd Bergmannacaefc22005-05-18 14:40:59 +020047static void debugfs_u8_set(void *data, u64 val)
48{
49 *(u8 *)data = val;
50}
51static u64 debugfs_u8_get(void *data)
52{
53 return *(u8 *)data;
54}
55DEFINE_SIMPLE_ATTRIBUTE(fops_u8, debugfs_u8_get, debugfs_u8_set, "%llu\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -070056
57/**
Randy Dunlap6468b3a2006-07-20 08:16:42 -070058 * debugfs_create_u8 - create a debugfs file that is used to read and write an unsigned 8-bit value
Linus Torvalds1da177e2005-04-16 15:20:36 -070059 * @name: a pointer to a string containing the name of the file to create.
60 * @mode: the permission that the file should have
61 * @parent: a pointer to the parent dentry for this file. This should be a
Randy Dunlap6468b3a2006-07-20 08:16:42 -070062 * directory dentry if set. If this parameter is %NULL, then the
Linus Torvalds1da177e2005-04-16 15:20:36 -070063 * file will be created in the root of the debugfs filesystem.
64 * @value: a pointer to the variable that the file should read to and write
65 * from.
66 *
67 * This function creates a file in debugfs with the given name that
68 * contains the value of the variable @value. If the @mode variable is so
69 * set, it can be read from, and written to.
70 *
71 * This function will return a pointer to a dentry if it succeeds. This
72 * pointer must be passed to the debugfs_remove() function when the file is
73 * to be removed (no automatic cleanup happens if your module is unloaded,
Randy Dunlap6468b3a2006-07-20 08:16:42 -070074 * you are responsible here.) If an error occurs, %NULL will be returned.
Linus Torvalds1da177e2005-04-16 15:20:36 -070075 *
Randy Dunlap6468b3a2006-07-20 08:16:42 -070076 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
Linus Torvalds1da177e2005-04-16 15:20:36 -070077 * returned. It is not wise to check for this value, but rather, check for
Randy Dunlap6468b3a2006-07-20 08:16:42 -070078 * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
Linus Torvalds1da177e2005-04-16 15:20:36 -070079 * code.
80 */
81struct dentry *debugfs_create_u8(const char *name, mode_t mode,
82 struct dentry *parent, u8 *value)
83{
84 return debugfs_create_file(name, mode, parent, value, &fops_u8);
85}
86EXPORT_SYMBOL_GPL(debugfs_create_u8);
87
Arnd Bergmannacaefc22005-05-18 14:40:59 +020088static void debugfs_u16_set(void *data, u64 val)
89{
90 *(u16 *)data = val;
91}
92static u64 debugfs_u16_get(void *data)
93{
94 return *(u16 *)data;
95}
96DEFINE_SIMPLE_ATTRIBUTE(fops_u16, debugfs_u16_get, debugfs_u16_set, "%llu\n");
97
Linus Torvalds1da177e2005-04-16 15:20:36 -070098/**
Randy Dunlap6468b3a2006-07-20 08:16:42 -070099 * debugfs_create_u16 - create a debugfs file that is used to read and write an unsigned 16-bit value
Linus Torvalds1da177e2005-04-16 15:20:36 -0700100 * @name: a pointer to a string containing the name of the file to create.
101 * @mode: the permission that the file should have
102 * @parent: a pointer to the parent dentry for this file. This should be a
Randy Dunlap6468b3a2006-07-20 08:16:42 -0700103 * directory dentry if set. If this parameter is %NULL, then the
Linus Torvalds1da177e2005-04-16 15:20:36 -0700104 * file will be created in the root of the debugfs filesystem.
105 * @value: a pointer to the variable that the file should read to and write
106 * from.
107 *
108 * This function creates a file in debugfs with the given name that
109 * contains the value of the variable @value. If the @mode variable is so
110 * set, it can be read from, and written to.
111 *
112 * This function will return a pointer to a dentry if it succeeds. This
113 * pointer must be passed to the debugfs_remove() function when the file is
114 * to be removed (no automatic cleanup happens if your module is unloaded,
Randy Dunlap6468b3a2006-07-20 08:16:42 -0700115 * you are responsible here.) If an error occurs, %NULL will be returned.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700116 *
Randy Dunlap6468b3a2006-07-20 08:16:42 -0700117 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
Linus Torvalds1da177e2005-04-16 15:20:36 -0700118 * returned. It is not wise to check for this value, but rather, check for
Randy Dunlap6468b3a2006-07-20 08:16:42 -0700119 * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
Linus Torvalds1da177e2005-04-16 15:20:36 -0700120 * code.
121 */
122struct dentry *debugfs_create_u16(const char *name, mode_t mode,
123 struct dentry *parent, u16 *value)
124{
125 return debugfs_create_file(name, mode, parent, value, &fops_u16);
126}
127EXPORT_SYMBOL_GPL(debugfs_create_u16);
128
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200129static void debugfs_u32_set(void *data, u64 val)
130{
131 *(u32 *)data = val;
132}
133static u64 debugfs_u32_get(void *data)
134{
135 return *(u32 *)data;
136}
137DEFINE_SIMPLE_ATTRIBUTE(fops_u32, debugfs_u32_get, debugfs_u32_set, "%llu\n");
138
Linus Torvalds1da177e2005-04-16 15:20:36 -0700139/**
Randy Dunlap6468b3a2006-07-20 08:16:42 -0700140 * debugfs_create_u32 - create a debugfs file that is used to read and write an unsigned 32-bit value
Linus Torvalds1da177e2005-04-16 15:20:36 -0700141 * @name: a pointer to a string containing the name of the file to create.
142 * @mode: the permission that the file should have
143 * @parent: a pointer to the parent dentry for this file. This should be a
Randy Dunlap6468b3a2006-07-20 08:16:42 -0700144 * directory dentry if set. If this parameter is %NULL, then the
Linus Torvalds1da177e2005-04-16 15:20:36 -0700145 * file will be created in the root of the debugfs filesystem.
146 * @value: a pointer to the variable that the file should read to and write
147 * from.
148 *
149 * This function creates a file in debugfs with the given name that
150 * contains the value of the variable @value. If the @mode variable is so
151 * set, it can be read from, and written to.
152 *
153 * This function will return a pointer to a dentry if it succeeds. This
154 * pointer must be passed to the debugfs_remove() function when the file is
155 * to be removed (no automatic cleanup happens if your module is unloaded,
Randy Dunlap6468b3a2006-07-20 08:16:42 -0700156 * you are responsible here.) If an error occurs, %NULL will be returned.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700157 *
Randy Dunlap6468b3a2006-07-20 08:16:42 -0700158 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
Linus Torvalds1da177e2005-04-16 15:20:36 -0700159 * returned. It is not wise to check for this value, but rather, check for
Randy Dunlap6468b3a2006-07-20 08:16:42 -0700160 * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
Linus Torvalds1da177e2005-04-16 15:20:36 -0700161 * code.
162 */
163struct dentry *debugfs_create_u32(const char *name, mode_t mode,
164 struct dentry *parent, u32 *value)
165{
166 return debugfs_create_file(name, mode, parent, value, &fops_u32);
167}
168EXPORT_SYMBOL_GPL(debugfs_create_u32);
169
170static ssize_t read_file_bool(struct file *file, char __user *user_buf,
171 size_t count, loff_t *ppos)
172{
173 char buf[3];
174 u32 *val = file->private_data;
175
176 if (*val)
177 buf[0] = 'Y';
178 else
179 buf[0] = 'N';
180 buf[1] = '\n';
181 buf[2] = 0x00;
182 return simple_read_from_buffer(user_buf, count, ppos, buf, 2);
183}
184
185static ssize_t write_file_bool(struct file *file, const char __user *user_buf,
186 size_t count, loff_t *ppos)
187{
188 char buf[32];
189 int buf_size;
190 u32 *val = file->private_data;
191
192 buf_size = min(count, (sizeof(buf)-1));
193 if (copy_from_user(buf, user_buf, buf_size))
194 return -EFAULT;
195
196 switch (buf[0]) {
197 case 'y':
198 case 'Y':
199 case '1':
200 *val = 1;
201 break;
202 case 'n':
203 case 'N':
204 case '0':
205 *val = 0;
206 break;
207 }
208
209 return count;
210}
211
Arjan van de Ven4b6f5d22006-03-28 01:56:42 -0800212static const struct file_operations fops_bool = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700213 .read = read_file_bool,
214 .write = write_file_bool,
215 .open = default_open,
216};
217
218/**
Randy Dunlap6468b3a2006-07-20 08:16:42 -0700219 * debugfs_create_bool - create a debugfs file that is used to read and write a boolean value
Linus Torvalds1da177e2005-04-16 15:20:36 -0700220 * @name: a pointer to a string containing the name of the file to create.
221 * @mode: the permission that the file should have
222 * @parent: a pointer to the parent dentry for this file. This should be a
Randy Dunlap6468b3a2006-07-20 08:16:42 -0700223 * directory dentry if set. If this parameter is %NULL, then the
Linus Torvalds1da177e2005-04-16 15:20:36 -0700224 * file will be created in the root of the debugfs filesystem.
225 * @value: a pointer to the variable that the file should read to and write
226 * from.
227 *
228 * This function creates a file in debugfs with the given name that
229 * contains the value of the variable @value. If the @mode variable is so
230 * set, it can be read from, and written to.
231 *
232 * This function will return a pointer to a dentry if it succeeds. This
233 * pointer must be passed to the debugfs_remove() function when the file is
234 * to be removed (no automatic cleanup happens if your module is unloaded,
Randy Dunlap6468b3a2006-07-20 08:16:42 -0700235 * you are responsible here.) If an error occurs, %NULL will be returned.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700236 *
Randy Dunlap6468b3a2006-07-20 08:16:42 -0700237 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
Linus Torvalds1da177e2005-04-16 15:20:36 -0700238 * returned. It is not wise to check for this value, but rather, check for
Randy Dunlap6468b3a2006-07-20 08:16:42 -0700239 * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
Linus Torvalds1da177e2005-04-16 15:20:36 -0700240 * code.
241 */
242struct dentry *debugfs_create_bool(const char *name, mode_t mode,
243 struct dentry *parent, u32 *value)
244{
245 return debugfs_create_file(name, mode, parent, value, &fops_bool);
246}
247EXPORT_SYMBOL_GPL(debugfs_create_bool);
248
Michael Ellermandd308bc2006-03-07 21:41:59 +1100249static ssize_t read_file_blob(struct file *file, char __user *user_buf,
250 size_t count, loff_t *ppos)
251{
252 struct debugfs_blob_wrapper *blob = file->private_data;
253 return simple_read_from_buffer(user_buf, count, ppos, blob->data,
254 blob->size);
255}
256
257static struct file_operations fops_blob = {
258 .read = read_file_blob,
259 .open = default_open,
260};
261
262/**
Randy Dunlap6468b3a2006-07-20 08:16:42 -0700263 * debugfs_create_blob - create a debugfs file that is used to read and write a binary blob
Michael Ellermandd308bc2006-03-07 21:41:59 +1100264 * @name: a pointer to a string containing the name of the file to create.
265 * @mode: the permission that the file should have
266 * @parent: a pointer to the parent dentry for this file. This should be a
Randy Dunlap6468b3a2006-07-20 08:16:42 -0700267 * directory dentry if set. If this parameter is %NULL, then the
Michael Ellermandd308bc2006-03-07 21:41:59 +1100268 * file will be created in the root of the debugfs filesystem.
269 * @blob: a pointer to a struct debugfs_blob_wrapper which contains a pointer
270 * to the blob data and the size of the data.
271 *
272 * This function creates a file in debugfs with the given name that exports
273 * @blob->data as a binary blob. If the @mode variable is so set it can be
274 * read from. Writing is not supported.
275 *
276 * This function will return a pointer to a dentry if it succeeds. This
277 * pointer must be passed to the debugfs_remove() function when the file is
278 * to be removed (no automatic cleanup happens if your module is unloaded,
Randy Dunlap6468b3a2006-07-20 08:16:42 -0700279 * you are responsible here.) If an error occurs, %NULL will be returned.
Michael Ellermandd308bc2006-03-07 21:41:59 +1100280 *
Randy Dunlap6468b3a2006-07-20 08:16:42 -0700281 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
Michael Ellermandd308bc2006-03-07 21:41:59 +1100282 * returned. It is not wise to check for this value, but rather, check for
Randy Dunlap6468b3a2006-07-20 08:16:42 -0700283 * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
Michael Ellermandd308bc2006-03-07 21:41:59 +1100284 * code.
285 */
286struct dentry *debugfs_create_blob(const char *name, mode_t mode,
287 struct dentry *parent,
288 struct debugfs_blob_wrapper *blob)
289{
290 return debugfs_create_file(name, mode, parent, blob, &fops_blob);
291}
292EXPORT_SYMBOL_GPL(debugfs_create_blob);