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1da177e4 LT |
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 | ||
1da177e4 LT |
16 | #include <linux/module.h> |
17 | #include <linux/fs.h> | |
18 | #include <linux/pagemap.h> | |
66f54963 | 19 | #include <linux/namei.h> |
1da177e4 LT |
20 | #include <linux/debugfs.h> |
21 | ||
22 | static ssize_t default_read_file(struct file *file, char __user *buf, | |
23 | size_t count, loff_t *ppos) | |
24 | { | |
25 | return 0; | |
26 | } | |
27 | ||
28 | static 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 | ||
34 | static int default_open(struct inode *inode, struct file *file) | |
35 | { | |
8e18e294 TT |
36 | if (inode->i_private) |
37 | file->private_data = inode->i_private; | |
1da177e4 LT |
38 | |
39 | return 0; | |
40 | } | |
41 | ||
4b6f5d20 | 42 | const struct file_operations debugfs_file_operations = { |
1da177e4 LT |
43 | .read = default_read_file, |
44 | .write = default_write_file, | |
45 | .open = default_open, | |
46 | }; | |
47 | ||
66f54963 PO |
48 | static void *debugfs_follow_link(struct dentry *dentry, struct nameidata *nd) |
49 | { | |
50 | nd_set_link(nd, dentry->d_inode->i_private); | |
51 | return NULL; | |
52 | } | |
53 | ||
54 | const struct inode_operations debugfs_link_operations = { | |
55 | .readlink = generic_readlink, | |
56 | .follow_link = debugfs_follow_link, | |
57 | }; | |
58 | ||
acaefc25 AB |
59 | static void debugfs_u8_set(void *data, u64 val) |
60 | { | |
61 | *(u8 *)data = val; | |
62 | } | |
63 | static u64 debugfs_u8_get(void *data) | |
64 | { | |
65 | return *(u8 *)data; | |
66 | } | |
67 | DEFINE_SIMPLE_ATTRIBUTE(fops_u8, debugfs_u8_get, debugfs_u8_set, "%llu\n"); | |
1da177e4 LT |
68 | |
69 | /** | |
6468b3af | 70 | * debugfs_create_u8 - create a debugfs file that is used to read and write an unsigned 8-bit value |
1da177e4 LT |
71 | * @name: a pointer to a string containing the name of the file to create. |
72 | * @mode: the permission that the file should have | |
73 | * @parent: a pointer to the parent dentry for this file. This should be a | |
6468b3af | 74 | * directory dentry if set. If this parameter is %NULL, then the |
1da177e4 LT |
75 | * file will be created in the root of the debugfs filesystem. |
76 | * @value: a pointer to the variable that the file should read to and write | |
77 | * from. | |
78 | * | |
79 | * This function creates a file in debugfs with the given name that | |
80 | * contains the value of the variable @value. If the @mode variable is so | |
81 | * set, it can be read from, and written to. | |
82 | * | |
83 | * This function will return a pointer to a dentry if it succeeds. This | |
84 | * pointer must be passed to the debugfs_remove() function when the file is | |
85 | * to be removed (no automatic cleanup happens if your module is unloaded, | |
6468b3af | 86 | * you are responsible here.) If an error occurs, %NULL will be returned. |
1da177e4 | 87 | * |
6468b3af | 88 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be |
1da177e4 | 89 | * returned. It is not wise to check for this value, but rather, check for |
6468b3af | 90 | * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling |
1da177e4 LT |
91 | * code. |
92 | */ | |
93 | struct dentry *debugfs_create_u8(const char *name, mode_t mode, | |
94 | struct dentry *parent, u8 *value) | |
95 | { | |
96 | return debugfs_create_file(name, mode, parent, value, &fops_u8); | |
97 | } | |
98 | EXPORT_SYMBOL_GPL(debugfs_create_u8); | |
99 | ||
acaefc25 AB |
100 | static void debugfs_u16_set(void *data, u64 val) |
101 | { | |
102 | *(u16 *)data = val; | |
103 | } | |
104 | static u64 debugfs_u16_get(void *data) | |
105 | { | |
106 | return *(u16 *)data; | |
107 | } | |
108 | DEFINE_SIMPLE_ATTRIBUTE(fops_u16, debugfs_u16_get, debugfs_u16_set, "%llu\n"); | |
109 | ||
1da177e4 | 110 | /** |
6468b3af | 111 | * debugfs_create_u16 - create a debugfs file that is used to read and write an unsigned 16-bit value |
1da177e4 LT |
112 | * @name: a pointer to a string containing the name of the file to create. |
113 | * @mode: the permission that the file should have | |
114 | * @parent: a pointer to the parent dentry for this file. This should be a | |
6468b3af | 115 | * directory dentry if set. If this parameter is %NULL, then the |
1da177e4 LT |
116 | * file will be created in the root of the debugfs filesystem. |
117 | * @value: a pointer to the variable that the file should read to and write | |
118 | * from. | |
119 | * | |
120 | * This function creates a file in debugfs with the given name that | |
121 | * contains the value of the variable @value. If the @mode variable is so | |
122 | * set, it can be read from, and written to. | |
123 | * | |
124 | * This function will return a pointer to a dentry if it succeeds. This | |
125 | * pointer must be passed to the debugfs_remove() function when the file is | |
126 | * to be removed (no automatic cleanup happens if your module is unloaded, | |
6468b3af | 127 | * you are responsible here.) If an error occurs, %NULL will be returned. |
1da177e4 | 128 | * |
6468b3af | 129 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be |
1da177e4 | 130 | * returned. It is not wise to check for this value, but rather, check for |
6468b3af | 131 | * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling |
1da177e4 LT |
132 | * code. |
133 | */ | |
134 | struct dentry *debugfs_create_u16(const char *name, mode_t mode, | |
135 | struct dentry *parent, u16 *value) | |
136 | { | |
137 | return debugfs_create_file(name, mode, parent, value, &fops_u16); | |
138 | } | |
139 | EXPORT_SYMBOL_GPL(debugfs_create_u16); | |
140 | ||
acaefc25 AB |
141 | static void debugfs_u32_set(void *data, u64 val) |
142 | { | |
143 | *(u32 *)data = val; | |
144 | } | |
145 | static u64 debugfs_u32_get(void *data) | |
146 | { | |
147 | return *(u32 *)data; | |
148 | } | |
149 | DEFINE_SIMPLE_ATTRIBUTE(fops_u32, debugfs_u32_get, debugfs_u32_set, "%llu\n"); | |
150 | ||
1da177e4 | 151 | /** |
6468b3af | 152 | * debugfs_create_u32 - create a debugfs file that is used to read and write an unsigned 32-bit value |
1da177e4 LT |
153 | * @name: a pointer to a string containing the name of the file to create. |
154 | * @mode: the permission that the file should have | |
155 | * @parent: a pointer to the parent dentry for this file. This should be a | |
6468b3af | 156 | * directory dentry if set. If this parameter is %NULL, then the |
1da177e4 LT |
157 | * file will be created in the root of the debugfs filesystem. |
158 | * @value: a pointer to the variable that the file should read to and write | |
159 | * from. | |
160 | * | |
161 | * This function creates a file in debugfs with the given name that | |
162 | * contains the value of the variable @value. If the @mode variable is so | |
163 | * set, it can be read from, and written to. | |
164 | * | |
165 | * This function will return a pointer to a dentry if it succeeds. This | |
166 | * pointer must be passed to the debugfs_remove() function when the file is | |
167 | * to be removed (no automatic cleanup happens if your module is unloaded, | |
6468b3af | 168 | * you are responsible here.) If an error occurs, %NULL will be returned. |
1da177e4 | 169 | * |
6468b3af | 170 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be |
1da177e4 | 171 | * returned. It is not wise to check for this value, but rather, check for |
6468b3af | 172 | * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling |
1da177e4 LT |
173 | * code. |
174 | */ | |
175 | struct dentry *debugfs_create_u32(const char *name, mode_t mode, | |
176 | struct dentry *parent, u32 *value) | |
177 | { | |
178 | return debugfs_create_file(name, mode, parent, value, &fops_u32); | |
179 | } | |
180 | EXPORT_SYMBOL_GPL(debugfs_create_u32); | |
181 | ||
8447891f ME |
182 | static void debugfs_u64_set(void *data, u64 val) |
183 | { | |
184 | *(u64 *)data = val; | |
185 | } | |
186 | ||
187 | static u64 debugfs_u64_get(void *data) | |
188 | { | |
189 | return *(u64 *)data; | |
190 | } | |
191 | DEFINE_SIMPLE_ATTRIBUTE(fops_u64, debugfs_u64_get, debugfs_u64_set, "%llu\n"); | |
192 | ||
193 | /** | |
194 | * debugfs_create_u64 - create a debugfs file that is used to read and write an unsigned 64-bit value | |
195 | * @name: a pointer to a string containing the name of the file to create. | |
196 | * @mode: the permission that the file should have | |
197 | * @parent: a pointer to the parent dentry for this file. This should be a | |
198 | * directory dentry if set. If this parameter is %NULL, then the | |
199 | * file will be created in the root of the debugfs filesystem. | |
200 | * @value: a pointer to the variable that the file should read to and write | |
201 | * from. | |
202 | * | |
203 | * This function creates a file in debugfs with the given name that | |
204 | * contains the value of the variable @value. If the @mode variable is so | |
205 | * set, it can be read from, and written to. | |
206 | * | |
207 | * This function will return a pointer to a dentry if it succeeds. This | |
208 | * pointer must be passed to the debugfs_remove() function when the file is | |
209 | * to be removed (no automatic cleanup happens if your module is unloaded, | |
210 | * you are responsible here.) If an error occurs, %NULL will be returned. | |
211 | * | |
212 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be | |
213 | * returned. It is not wise to check for this value, but rather, check for | |
214 | * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling | |
215 | * code. | |
216 | */ | |
217 | struct dentry *debugfs_create_u64(const char *name, mode_t mode, | |
218 | struct dentry *parent, u64 *value) | |
219 | { | |
220 | return debugfs_create_file(name, mode, parent, value, &fops_u64); | |
221 | } | |
222 | EXPORT_SYMBOL_GPL(debugfs_create_u64); | |
223 | ||
1da177e4 LT |
224 | static ssize_t read_file_bool(struct file *file, char __user *user_buf, |
225 | size_t count, loff_t *ppos) | |
226 | { | |
227 | char buf[3]; | |
228 | u32 *val = file->private_data; | |
229 | ||
230 | if (*val) | |
231 | buf[0] = 'Y'; | |
232 | else | |
233 | buf[0] = 'N'; | |
234 | buf[1] = '\n'; | |
235 | buf[2] = 0x00; | |
236 | return simple_read_from_buffer(user_buf, count, ppos, buf, 2); | |
237 | } | |
238 | ||
239 | static ssize_t write_file_bool(struct file *file, const char __user *user_buf, | |
240 | size_t count, loff_t *ppos) | |
241 | { | |
242 | char buf[32]; | |
243 | int buf_size; | |
244 | u32 *val = file->private_data; | |
245 | ||
246 | buf_size = min(count, (sizeof(buf)-1)); | |
247 | if (copy_from_user(buf, user_buf, buf_size)) | |
248 | return -EFAULT; | |
249 | ||
250 | switch (buf[0]) { | |
251 | case 'y': | |
252 | case 'Y': | |
253 | case '1': | |
254 | *val = 1; | |
255 | break; | |
256 | case 'n': | |
257 | case 'N': | |
258 | case '0': | |
259 | *val = 0; | |
260 | break; | |
261 | } | |
262 | ||
263 | return count; | |
264 | } | |
265 | ||
4b6f5d20 | 266 | static const struct file_operations fops_bool = { |
1da177e4 LT |
267 | .read = read_file_bool, |
268 | .write = write_file_bool, | |
269 | .open = default_open, | |
270 | }; | |
271 | ||
272 | /** | |
6468b3af | 273 | * debugfs_create_bool - create a debugfs file that is used to read and write a boolean value |
1da177e4 LT |
274 | * @name: a pointer to a string containing the name of the file to create. |
275 | * @mode: the permission that the file should have | |
276 | * @parent: a pointer to the parent dentry for this file. This should be a | |
6468b3af | 277 | * directory dentry if set. If this parameter is %NULL, then the |
1da177e4 LT |
278 | * file will be created in the root of the debugfs filesystem. |
279 | * @value: a pointer to the variable that the file should read to and write | |
280 | * from. | |
281 | * | |
282 | * This function creates a file in debugfs with the given name that | |
283 | * contains the value of the variable @value. If the @mode variable is so | |
284 | * set, it can be read from, and written to. | |
285 | * | |
286 | * This function will return a pointer to a dentry if it succeeds. This | |
287 | * pointer must be passed to the debugfs_remove() function when the file is | |
288 | * to be removed (no automatic cleanup happens if your module is unloaded, | |
6468b3af | 289 | * you are responsible here.) If an error occurs, %NULL will be returned. |
1da177e4 | 290 | * |
6468b3af | 291 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be |
1da177e4 | 292 | * returned. It is not wise to check for this value, but rather, check for |
6468b3af | 293 | * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling |
1da177e4 LT |
294 | * code. |
295 | */ | |
296 | struct dentry *debugfs_create_bool(const char *name, mode_t mode, | |
297 | struct dentry *parent, u32 *value) | |
298 | { | |
299 | return debugfs_create_file(name, mode, parent, value, &fops_bool); | |
300 | } | |
301 | EXPORT_SYMBOL_GPL(debugfs_create_bool); | |
302 | ||
dd308bc3 ME |
303 | static ssize_t read_file_blob(struct file *file, char __user *user_buf, |
304 | size_t count, loff_t *ppos) | |
305 | { | |
306 | struct debugfs_blob_wrapper *blob = file->private_data; | |
307 | return simple_read_from_buffer(user_buf, count, ppos, blob->data, | |
308 | blob->size); | |
309 | } | |
310 | ||
00977a59 | 311 | static const struct file_operations fops_blob = { |
dd308bc3 ME |
312 | .read = read_file_blob, |
313 | .open = default_open, | |
314 | }; | |
315 | ||
316 | /** | |
6468b3af | 317 | * debugfs_create_blob - create a debugfs file that is used to read and write a binary blob |
dd308bc3 ME |
318 | * @name: a pointer to a string containing the name of the file to create. |
319 | * @mode: the permission that the file should have | |
320 | * @parent: a pointer to the parent dentry for this file. This should be a | |
6468b3af | 321 | * directory dentry if set. If this parameter is %NULL, then the |
dd308bc3 ME |
322 | * file will be created in the root of the debugfs filesystem. |
323 | * @blob: a pointer to a struct debugfs_blob_wrapper which contains a pointer | |
324 | * to the blob data and the size of the data. | |
325 | * | |
326 | * This function creates a file in debugfs with the given name that exports | |
327 | * @blob->data as a binary blob. If the @mode variable is so set it can be | |
328 | * read from. Writing is not supported. | |
329 | * | |
330 | * This function will return a pointer to a dentry if it succeeds. This | |
331 | * pointer must be passed to the debugfs_remove() function when the file is | |
332 | * to be removed (no automatic cleanup happens if your module is unloaded, | |
6468b3af | 333 | * you are responsible here.) If an error occurs, %NULL will be returned. |
dd308bc3 | 334 | * |
6468b3af | 335 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be |
dd308bc3 | 336 | * returned. It is not wise to check for this value, but rather, check for |
6468b3af | 337 | * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling |
dd308bc3 ME |
338 | * code. |
339 | */ | |
340 | struct dentry *debugfs_create_blob(const char *name, mode_t mode, | |
341 | struct dentry *parent, | |
342 | struct debugfs_blob_wrapper *blob) | |
343 | { | |
344 | return debugfs_create_file(name, mode, parent, blob, &fops_blob); | |
345 | } | |
346 | EXPORT_SYMBOL_GPL(debugfs_create_blob); |