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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 | ||
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 | ||
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 | { | |
36 | if (inode->u.generic_ip) | |
37 | file->private_data = inode->u.generic_ip; | |
38 | ||
39 | return 0; | |
40 | } | |
41 | ||
42 | struct file_operations debugfs_file_operations = { | |
43 | .read = default_read_file, | |
44 | .write = default_write_file, | |
45 | .open = default_open, | |
46 | }; | |
47 | ||
48 | #define simple_type(type, format, temptype, strtolfn) \ | |
49 | static ssize_t read_file_##type(struct file *file, char __user *user_buf, \ | |
50 | size_t count, loff_t *ppos) \ | |
51 | { \ | |
52 | char buf[32]; \ | |
53 | type *val = file->private_data; \ | |
54 | \ | |
55 | snprintf(buf, sizeof(buf), format "\n", *val); \ | |
56 | return simple_read_from_buffer(user_buf, count, ppos, buf, strlen(buf));\ | |
57 | } \ | |
58 | static ssize_t write_file_##type(struct file *file, const char __user *user_buf,\ | |
59 | size_t count, loff_t *ppos) \ | |
60 | { \ | |
61 | char *endp; \ | |
62 | char buf[32]; \ | |
63 | int buf_size; \ | |
64 | type *val = file->private_data; \ | |
65 | temptype tmp; \ | |
66 | \ | |
67 | memset(buf, 0x00, sizeof(buf)); \ | |
68 | buf_size = min(count, (sizeof(buf)-1)); \ | |
69 | if (copy_from_user(buf, user_buf, buf_size)) \ | |
70 | return -EFAULT; \ | |
71 | \ | |
72 | tmp = strtolfn(buf, &endp, 0); \ | |
73 | if ((endp == buf) || ((type)tmp != tmp)) \ | |
74 | return -EINVAL; \ | |
75 | *val = tmp; \ | |
76 | return count; \ | |
77 | } \ | |
78 | static struct file_operations fops_##type = { \ | |
79 | .read = read_file_##type, \ | |
80 | .write = write_file_##type, \ | |
81 | .open = default_open, \ | |
82 | }; | |
83 | simple_type(u8, "%c", unsigned long, simple_strtoul); | |
84 | simple_type(u16, "%hi", unsigned long, simple_strtoul); | |
85 | simple_type(u32, "%i", unsigned long, simple_strtoul); | |
86 | ||
87 | /** | |
88 | * debugfs_create_u8 - create a file in the debugfs filesystem that is used to read and write a unsigned 8 bit value. | |
89 | * | |
90 | * @name: a pointer to a string containing the name of the file to create. | |
91 | * @mode: the permission that the file should have | |
92 | * @parent: a pointer to the parent dentry for this file. This should be a | |
93 | * directory dentry if set. If this paramater is NULL, then the | |
94 | * file will be created in the root of the debugfs filesystem. | |
95 | * @value: a pointer to the variable that the file should read to and write | |
96 | * from. | |
97 | * | |
98 | * This function creates a file in debugfs with the given name that | |
99 | * contains the value of the variable @value. If the @mode variable is so | |
100 | * set, it can be read from, and written to. | |
101 | * | |
102 | * This function will return a pointer to a dentry if it succeeds. This | |
103 | * pointer must be passed to the debugfs_remove() function when the file is | |
104 | * to be removed (no automatic cleanup happens if your module is unloaded, | |
105 | * you are responsible here.) If an error occurs, NULL will be returned. | |
106 | * | |
107 | * If debugfs is not enabled in the kernel, the value -ENODEV will be | |
108 | * returned. It is not wise to check for this value, but rather, check for | |
109 | * NULL or !NULL instead as to eliminate the need for #ifdef in the calling | |
110 | * code. | |
111 | */ | |
112 | struct dentry *debugfs_create_u8(const char *name, mode_t mode, | |
113 | struct dentry *parent, u8 *value) | |
114 | { | |
115 | return debugfs_create_file(name, mode, parent, value, &fops_u8); | |
116 | } | |
117 | EXPORT_SYMBOL_GPL(debugfs_create_u8); | |
118 | ||
119 | /** | |
120 | * debugfs_create_u16 - create a file in the debugfs filesystem that is used to read and write a unsigned 8 bit value. | |
121 | * | |
122 | * @name: a pointer to a string containing the name of the file to create. | |
123 | * @mode: the permission that the file should have | |
124 | * @parent: a pointer to the parent dentry for this file. This should be a | |
125 | * directory dentry if set. If this paramater is NULL, then the | |
126 | * file will be created in the root of the debugfs filesystem. | |
127 | * @value: a pointer to the variable that the file should read to and write | |
128 | * from. | |
129 | * | |
130 | * This function creates a file in debugfs with the given name that | |
131 | * contains the value of the variable @value. If the @mode variable is so | |
132 | * set, it can be read from, and written to. | |
133 | * | |
134 | * This function will return a pointer to a dentry if it succeeds. This | |
135 | * pointer must be passed to the debugfs_remove() function when the file is | |
136 | * to be removed (no automatic cleanup happens if your module is unloaded, | |
137 | * you are responsible here.) If an error occurs, NULL will be returned. | |
138 | * | |
139 | * If debugfs is not enabled in the kernel, the value -ENODEV will be | |
140 | * returned. It is not wise to check for this value, but rather, check for | |
141 | * NULL or !NULL instead as to eliminate the need for #ifdef in the calling | |
142 | * code. | |
143 | */ | |
144 | struct dentry *debugfs_create_u16(const char *name, mode_t mode, | |
145 | struct dentry *parent, u16 *value) | |
146 | { | |
147 | return debugfs_create_file(name, mode, parent, value, &fops_u16); | |
148 | } | |
149 | EXPORT_SYMBOL_GPL(debugfs_create_u16); | |
150 | ||
151 | /** | |
152 | * debugfs_create_u32 - create a file in the debugfs filesystem that is used to read and write a unsigned 8 bit value. | |
153 | * | |
154 | * @name: a pointer to a string containing the name of the file to create. | |
155 | * @mode: the permission that the file should have | |
156 | * @parent: a pointer to the parent dentry for this file. This should be a | |
157 | * directory dentry if set. If this paramater is NULL, then the | |
158 | * file will be created in the root of the debugfs filesystem. | |
159 | * @value: a pointer to the variable that the file should read to and write | |
160 | * from. | |
161 | * | |
162 | * This function creates a file in debugfs with the given name that | |
163 | * contains the value of the variable @value. If the @mode variable is so | |
164 | * set, it can be read from, and written to. | |
165 | * | |
166 | * This function will return a pointer to a dentry if it succeeds. This | |
167 | * pointer must be passed to the debugfs_remove() function when the file is | |
168 | * to be removed (no automatic cleanup happens if your module is unloaded, | |
169 | * you are responsible here.) If an error occurs, NULL will be returned. | |
170 | * | |
171 | * If debugfs is not enabled in the kernel, the value -ENODEV will be | |
172 | * returned. It is not wise to check for this value, but rather, check for | |
173 | * NULL or !NULL instead as to eliminate the need for #ifdef in the calling | |
174 | * code. | |
175 | */ | |
176 | struct dentry *debugfs_create_u32(const char *name, mode_t mode, | |
177 | struct dentry *parent, u32 *value) | |
178 | { | |
179 | return debugfs_create_file(name, mode, parent, value, &fops_u32); | |
180 | } | |
181 | EXPORT_SYMBOL_GPL(debugfs_create_u32); | |
182 | ||
183 | static ssize_t read_file_bool(struct file *file, char __user *user_buf, | |
184 | size_t count, loff_t *ppos) | |
185 | { | |
186 | char buf[3]; | |
187 | u32 *val = file->private_data; | |
188 | ||
189 | if (*val) | |
190 | buf[0] = 'Y'; | |
191 | else | |
192 | buf[0] = 'N'; | |
193 | buf[1] = '\n'; | |
194 | buf[2] = 0x00; | |
195 | return simple_read_from_buffer(user_buf, count, ppos, buf, 2); | |
196 | } | |
197 | ||
198 | static ssize_t write_file_bool(struct file *file, const char __user *user_buf, | |
199 | size_t count, loff_t *ppos) | |
200 | { | |
201 | char buf[32]; | |
202 | int buf_size; | |
203 | u32 *val = file->private_data; | |
204 | ||
205 | buf_size = min(count, (sizeof(buf)-1)); | |
206 | if (copy_from_user(buf, user_buf, buf_size)) | |
207 | return -EFAULT; | |
208 | ||
209 | switch (buf[0]) { | |
210 | case 'y': | |
211 | case 'Y': | |
212 | case '1': | |
213 | *val = 1; | |
214 | break; | |
215 | case 'n': | |
216 | case 'N': | |
217 | case '0': | |
218 | *val = 0; | |
219 | break; | |
220 | } | |
221 | ||
222 | return count; | |
223 | } | |
224 | ||
225 | static struct file_operations fops_bool = { | |
226 | .read = read_file_bool, | |
227 | .write = write_file_bool, | |
228 | .open = default_open, | |
229 | }; | |
230 | ||
231 | /** | |
232 | * debugfs_create_bool - create a file in the debugfs filesystem that is used to read and write a boolean value. | |
233 | * | |
234 | * @name: a pointer to a string containing the name of the file to create. | |
235 | * @mode: the permission that the file should have | |
236 | * @parent: a pointer to the parent dentry for this file. This should be a | |
237 | * directory dentry if set. If this paramater is NULL, then the | |
238 | * file will be created in the root of the debugfs filesystem. | |
239 | * @value: a pointer to the variable that the file should read to and write | |
240 | * from. | |
241 | * | |
242 | * This function creates a file in debugfs with the given name that | |
243 | * contains the value of the variable @value. If the @mode variable is so | |
244 | * set, it can be read from, and written to. | |
245 | * | |
246 | * This function will return a pointer to a dentry if it succeeds. This | |
247 | * pointer must be passed to the debugfs_remove() function when the file is | |
248 | * to be removed (no automatic cleanup happens if your module is unloaded, | |
249 | * you are responsible here.) If an error occurs, NULL will be returned. | |
250 | * | |
251 | * If debugfs is not enabled in the kernel, the value -ENODEV will be | |
252 | * returned. It is not wise to check for this value, but rather, check for | |
253 | * NULL or !NULL instead as to eliminate the need for #ifdef in the calling | |
254 | * code. | |
255 | */ | |
256 | struct dentry *debugfs_create_bool(const char *name, mode_t mode, | |
257 | struct dentry *parent, u32 *value) | |
258 | { | |
259 | return debugfs_create_file(name, mode, parent, value, &fops_bool); | |
260 | } | |
261 | EXPORT_SYMBOL_GPL(debugfs_create_bool); | |
262 |