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/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{
35 if (inode->u.generic_ip)
36 file->private_data = inode->u.generic_ip;
37
38 return 0;
39}
40
41const struct file_operations debugfs_file_operations = {
42 .read = default_read_file,
43 .write = default_write_file,
44 .open = default_open,
45};
46
47static 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");
56
57/**
58 * debugfs_create_u8 - create a file in the debugfs filesystem that is used to read and write an unsigned 8 bit value.
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 */
82struct 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}
87EXPORT_SYMBOL_GPL(debugfs_create_u8);
88
89static void debugfs_u16_set(void *data, u64 val)
90{
91 *(u16 *)data = val;
92}
93static u64 debugfs_u16_get(void *data)
94{
95 return *(u16 *)data;
96}
97DEFINE_SIMPLE_ATTRIBUTE(fops_u16, debugfs_u16_get, debugfs_u16_set, "%llu\n");
98
99/**
100 * debugfs_create_u16 - create a file in the debugfs filesystem that is used to read and write an unsigned 16 bit value.
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 */
124struct 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}
129EXPORT_SYMBOL_GPL(debugfs_create_u16);
130
131static void debugfs_u32_set(void *data, u64 val)
132{
133 *(u32 *)data = val;
134}
135static u64 debugfs_u32_get(void *data)
136{
137 return *(u32 *)data;
138}
139DEFINE_SIMPLE_ATTRIBUTE(fops_u32, debugfs_u32_get, debugfs_u32_set, "%llu\n");
140
141/**
142 * debugfs_create_u32 - create a file in the debugfs filesystem that is used to read and write an unsigned 32 bit value.
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 */
166struct 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}
171EXPORT_SYMBOL_GPL(debugfs_create_u32);
172
173static 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
188static 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
215static const struct file_operations fops_bool = {
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 */
246struct 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}
251EXPORT_SYMBOL_GPL(debugfs_create_bool);
252
253static 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
261static 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 */
292struct 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}
298EXPORT_SYMBOL_GPL(debugfs_create_blob);