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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> | |
19 | #include <linux/debugfs.h> | |
20 | ||
21 | static ssize_t default_read_file(struct file *file, char __user *buf, | |
22 | size_t count, loff_t *ppos) | |
23 | { | |
24 | return 0; | |
25 | } | |
26 | ||
27 | static 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 | ||
33 | static int default_open(struct inode *inode, struct file *file) | |
34 | { | |
35 | if (inode->u.generic_ip) | |
36 | file->private_data = inode->u.generic_ip; | |
37 | ||
38 | return 0; | |
39 | } | |
40 | ||
4b6f5d20 | 41 | const struct file_operations debugfs_file_operations = { |
1da177e4 LT |
42 | .read = default_read_file, |
43 | .write = default_write_file, | |
44 | .open = default_open, | |
45 | }; | |
46 | ||
acaefc25 AB |
47 | static void debugfs_u8_set(void *data, u64 val) |
48 | { | |
49 | *(u8 *)data = val; | |
50 | } | |
51 | static u64 debugfs_u8_get(void *data) | |
52 | { | |
53 | return *(u8 *)data; | |
54 | } | |
55 | DEFINE_SIMPLE_ATTRIBUTE(fops_u8, debugfs_u8_get, debugfs_u8_set, "%llu\n"); | |
1da177e4 LT |
56 | |
57 | /** | |
276e0c75 | 58 | * debugfs_create_u8 - create a file in the debugfs filesystem that is used to read and write an unsigned 8 bit value. |
1da177e4 LT |
59 | * |
60 | * @name: a pointer to a string containing the name of the file to create. | |
61 | * @mode: the permission that the file should have | |
62 | * @parent: a pointer to the parent dentry for this file. This should be a | |
63 | * directory dentry if set. If this paramater is NULL, then the | |
64 | * file will be created in the root of the debugfs filesystem. | |
65 | * @value: a pointer to the variable that the file should read to and write | |
66 | * from. | |
67 | * | |
68 | * This function creates a file in debugfs with the given name that | |
69 | * contains the value of the variable @value. If the @mode variable is so | |
70 | * set, it can be read from, and written to. | |
71 | * | |
72 | * This function will return a pointer to a dentry if it succeeds. This | |
73 | * pointer must be passed to the debugfs_remove() function when the file is | |
74 | * to be removed (no automatic cleanup happens if your module is unloaded, | |
75 | * you are responsible here.) If an error occurs, NULL will be returned. | |
76 | * | |
77 | * If debugfs is not enabled in the kernel, the value -ENODEV will be | |
78 | * returned. It is not wise to check for this value, but rather, check for | |
79 | * NULL or !NULL instead as to eliminate the need for #ifdef in the calling | |
80 | * code. | |
81 | */ | |
82 | struct dentry *debugfs_create_u8(const char *name, mode_t mode, | |
83 | struct dentry *parent, u8 *value) | |
84 | { | |
85 | return debugfs_create_file(name, mode, parent, value, &fops_u8); | |
86 | } | |
87 | EXPORT_SYMBOL_GPL(debugfs_create_u8); | |
88 | ||
acaefc25 AB |
89 | static void debugfs_u16_set(void *data, u64 val) |
90 | { | |
91 | *(u16 *)data = val; | |
92 | } | |
93 | static u64 debugfs_u16_get(void *data) | |
94 | { | |
95 | return *(u16 *)data; | |
96 | } | |
97 | DEFINE_SIMPLE_ATTRIBUTE(fops_u16, debugfs_u16_get, debugfs_u16_set, "%llu\n"); | |
98 | ||
1da177e4 | 99 | /** |
276e0c75 | 100 | * debugfs_create_u16 - create a file in the debugfs filesystem that is used to read and write an unsigned 16 bit value. |
1da177e4 LT |
101 | * |
102 | * @name: a pointer to a string containing the name of the file to create. | |
103 | * @mode: the permission that the file should have | |
104 | * @parent: a pointer to the parent dentry for this file. This should be a | |
105 | * directory dentry if set. If this paramater is NULL, then the | |
106 | * file will be created in the root of the debugfs filesystem. | |
107 | * @value: a pointer to the variable that the file should read to and write | |
108 | * from. | |
109 | * | |
110 | * This function creates a file in debugfs with the given name that | |
111 | * contains the value of the variable @value. If the @mode variable is so | |
112 | * set, it can be read from, and written to. | |
113 | * | |
114 | * This function will return a pointer to a dentry if it succeeds. This | |
115 | * pointer must be passed to the debugfs_remove() function when the file is | |
116 | * to be removed (no automatic cleanup happens if your module is unloaded, | |
117 | * you are responsible here.) If an error occurs, NULL will be returned. | |
118 | * | |
119 | * If debugfs is not enabled in the kernel, the value -ENODEV will be | |
120 | * returned. It is not wise to check for this value, but rather, check for | |
121 | * NULL or !NULL instead as to eliminate the need for #ifdef in the calling | |
122 | * code. | |
123 | */ | |
124 | struct dentry *debugfs_create_u16(const char *name, mode_t mode, | |
125 | struct dentry *parent, u16 *value) | |
126 | { | |
127 | return debugfs_create_file(name, mode, parent, value, &fops_u16); | |
128 | } | |
129 | EXPORT_SYMBOL_GPL(debugfs_create_u16); | |
130 | ||
acaefc25 AB |
131 | static void debugfs_u32_set(void *data, u64 val) |
132 | { | |
133 | *(u32 *)data = val; | |
134 | } | |
135 | static u64 debugfs_u32_get(void *data) | |
136 | { | |
137 | return *(u32 *)data; | |
138 | } | |
139 | DEFINE_SIMPLE_ATTRIBUTE(fops_u32, debugfs_u32_get, debugfs_u32_set, "%llu\n"); | |
140 | ||
1da177e4 | 141 | /** |
276e0c75 | 142 | * debugfs_create_u32 - create a file in the debugfs filesystem that is used to read and write an unsigned 32 bit value. |
1da177e4 LT |
143 | * |
144 | * @name: a pointer to a string containing the name of the file to create. | |
145 | * @mode: the permission that the file should have | |
146 | * @parent: a pointer to the parent dentry for this file. This should be a | |
147 | * directory dentry if set. If this paramater is NULL, then the | |
148 | * file will be created in the root of the debugfs filesystem. | |
149 | * @value: a pointer to the variable that the file should read to and write | |
150 | * from. | |
151 | * | |
152 | * This function creates a file in debugfs with the given name that | |
153 | * contains the value of the variable @value. If the @mode variable is so | |
154 | * set, it can be read from, and written to. | |
155 | * | |
156 | * This function will return a pointer to a dentry if it succeeds. This | |
157 | * pointer must be passed to the debugfs_remove() function when the file is | |
158 | * to be removed (no automatic cleanup happens if your module is unloaded, | |
159 | * you are responsible here.) If an error occurs, NULL will be returned. | |
160 | * | |
161 | * If debugfs is not enabled in the kernel, the value -ENODEV will be | |
162 | * returned. It is not wise to check for this value, but rather, check for | |
163 | * NULL or !NULL instead as to eliminate the need for #ifdef in the calling | |
164 | * code. | |
165 | */ | |
166 | struct dentry *debugfs_create_u32(const char *name, mode_t mode, | |
167 | struct dentry *parent, u32 *value) | |
168 | { | |
169 | return debugfs_create_file(name, mode, parent, value, &fops_u32); | |
170 | } | |
171 | EXPORT_SYMBOL_GPL(debugfs_create_u32); | |
172 | ||
173 | static ssize_t read_file_bool(struct file *file, char __user *user_buf, | |
174 | size_t count, loff_t *ppos) | |
175 | { | |
176 | char buf[3]; | |
177 | u32 *val = file->private_data; | |
178 | ||
179 | if (*val) | |
180 | buf[0] = 'Y'; | |
181 | else | |
182 | buf[0] = 'N'; | |
183 | buf[1] = '\n'; | |
184 | buf[2] = 0x00; | |
185 | return simple_read_from_buffer(user_buf, count, ppos, buf, 2); | |
186 | } | |
187 | ||
188 | static ssize_t write_file_bool(struct file *file, const char __user *user_buf, | |
189 | size_t count, loff_t *ppos) | |
190 | { | |
191 | char buf[32]; | |
192 | int buf_size; | |
193 | u32 *val = file->private_data; | |
194 | ||
195 | buf_size = min(count, (sizeof(buf)-1)); | |
196 | if (copy_from_user(buf, user_buf, buf_size)) | |
197 | return -EFAULT; | |
198 | ||
199 | switch (buf[0]) { | |
200 | case 'y': | |
201 | case 'Y': | |
202 | case '1': | |
203 | *val = 1; | |
204 | break; | |
205 | case 'n': | |
206 | case 'N': | |
207 | case '0': | |
208 | *val = 0; | |
209 | break; | |
210 | } | |
211 | ||
212 | return count; | |
213 | } | |
214 | ||
4b6f5d20 | 215 | static const struct file_operations fops_bool = { |
1da177e4 LT |
216 | .read = read_file_bool, |
217 | .write = write_file_bool, | |
218 | .open = default_open, | |
219 | }; | |
220 | ||
221 | /** | |
222 | * debugfs_create_bool - create a file in the debugfs filesystem that is used to read and write a boolean value. | |
223 | * | |
224 | * @name: a pointer to a string containing the name of the file to create. | |
225 | * @mode: the permission that the file should have | |
226 | * @parent: a pointer to the parent dentry for this file. This should be a | |
227 | * directory dentry if set. If this paramater is NULL, then the | |
228 | * file will be created in the root of the debugfs filesystem. | |
229 | * @value: a pointer to the variable that the file should read to and write | |
230 | * from. | |
231 | * | |
232 | * This function creates a file in debugfs with the given name that | |
233 | * contains the value of the variable @value. If the @mode variable is so | |
234 | * set, it can be read from, and written to. | |
235 | * | |
236 | * This function will return a pointer to a dentry if it succeeds. This | |
237 | * pointer must be passed to the debugfs_remove() function when the file is | |
238 | * to be removed (no automatic cleanup happens if your module is unloaded, | |
239 | * you are responsible here.) If an error occurs, NULL will be returned. | |
240 | * | |
241 | * If debugfs is not enabled in the kernel, the value -ENODEV will be | |
242 | * returned. It is not wise to check for this value, but rather, check for | |
243 | * NULL or !NULL instead as to eliminate the need for #ifdef in the calling | |
244 | * code. | |
245 | */ | |
246 | struct dentry *debugfs_create_bool(const char *name, mode_t mode, | |
247 | struct dentry *parent, u32 *value) | |
248 | { | |
249 | return debugfs_create_file(name, mode, parent, value, &fops_bool); | |
250 | } | |
251 | EXPORT_SYMBOL_GPL(debugfs_create_bool); | |
252 | ||
dd308bc3 ME |
253 | static ssize_t read_file_blob(struct file *file, char __user *user_buf, |
254 | size_t count, loff_t *ppos) | |
255 | { | |
256 | struct debugfs_blob_wrapper *blob = file->private_data; | |
257 | return simple_read_from_buffer(user_buf, count, ppos, blob->data, | |
258 | blob->size); | |
259 | } | |
260 | ||
261 | static struct file_operations fops_blob = { | |
262 | .read = read_file_blob, | |
263 | .open = default_open, | |
264 | }; | |
265 | ||
266 | /** | |
267 | * debugfs_create_blob - create a file in the debugfs filesystem that is | |
268 | * used to read and write a binary blob. | |
269 | * | |
270 | * @name: a pointer to a string containing the name of the file to create. | |
271 | * @mode: the permission that the file should have | |
272 | * @parent: a pointer to the parent dentry for this file. This should be a | |
273 | * directory dentry if set. If this paramater is NULL, then the | |
274 | * file will be created in the root of the debugfs filesystem. | |
275 | * @blob: a pointer to a struct debugfs_blob_wrapper which contains a pointer | |
276 | * to the blob data and the size of the data. | |
277 | * | |
278 | * This function creates a file in debugfs with the given name that exports | |
279 | * @blob->data as a binary blob. If the @mode variable is so set it can be | |
280 | * read from. Writing is not supported. | |
281 | * | |
282 | * This function will return a pointer to a dentry if it succeeds. This | |
283 | * pointer must be passed to the debugfs_remove() function when the file is | |
284 | * to be removed (no automatic cleanup happens if your module is unloaded, | |
285 | * you are responsible here.) If an error occurs, NULL will be returned. | |
286 | * | |
287 | * If debugfs is not enabled in the kernel, the value -ENODEV will be | |
288 | * returned. It is not wise to check for this value, but rather, check for | |
289 | * NULL or !NULL instead as to eliminate the need for #ifdef in the calling | |
290 | * code. | |
291 | */ | |
292 | struct dentry *debugfs_create_blob(const char *name, mode_t mode, | |
293 | struct dentry *parent, | |
294 | struct debugfs_blob_wrapper *blob) | |
295 | { | |
296 | return debugfs_create_file(name, mode, parent, blob, &fops_blob); | |
297 | } | |
298 | EXPORT_SYMBOL_GPL(debugfs_create_blob); |