1 /**
2 * @file oprofilefs.c
3 *
4 * @remark Copyright 2002 OProfile authors
5 * @remark Read the file COPYING
6 *
7 * @author John Levon
8 *
9 * A simple filesystem for configuration and
10 * access of oprofile.
11 */
12
13 #include <linux/init.h>
14 #include <linux/module.h>
15 #include <linux/oprofile.h>
16 #include <linux/fs.h>
17 #include <linux/pagemap.h>
18 #include <asm/uaccess.h>
19
20 #include "oprof.h"
21
22 #define OPROFILEFS_MAGIC 0x6f70726f
23
24 DEFINE_SPINLOCK(oprofilefs_lock);
25
26 static struct inode *oprofilefs_get_inode(struct super_block *sb, int mode)
27 {
28 struct inode *inode = new_inode(sb);
29
30 if (inode) {
31 inode->i_mode = mode;
32 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
33 }
34 return inode;
35 }
36
37
38 static struct super_operations s_ops = {
39 .statfs = simple_statfs,
40 .drop_inode = generic_delete_inode,
41 };
42
43
44 ssize_t oprofilefs_str_to_user(char const *str, char __user *buf, size_t count, loff_t *offset)
45 {
46 return simple_read_from_buffer(buf, count, offset, str, strlen(str));
47 }
48
49
50 #define TMPBUFSIZE 50
51
52 ssize_t oprofilefs_ulong_to_user(unsigned long val, char __user *buf, size_t count, loff_t *offset)
53 {
54 char tmpbuf[TMPBUFSIZE];
55 size_t maxlen = snprintf(tmpbuf, TMPBUFSIZE, "%lu\n", val);
56 if (maxlen > TMPBUFSIZE)
57 maxlen = TMPBUFSIZE;
58 return simple_read_from_buffer(buf, count, offset, tmpbuf, maxlen);
59 }
60
61
62 int oprofilefs_ulong_from_user(unsigned long *val, char const __user *buf, size_t count)
63 {
64 char tmpbuf[TMPBUFSIZE];
65 unsigned long flags;
66
67 if (!count)
68 return 0;
69
70 if (count > TMPBUFSIZE - 1)
71 return -EINVAL;
72
73 memset(tmpbuf, 0x0, TMPBUFSIZE);
74
75 if (copy_from_user(tmpbuf, buf, count))
76 return -EFAULT;
77
78 spin_lock_irqsave(&oprofilefs_lock, flags);
79 *val = simple_strtoul(tmpbuf, NULL, 0);
80 spin_unlock_irqrestore(&oprofilefs_lock, flags);
81 return 0;
82 }
83
84
85 static ssize_t ulong_read_file(struct file *file, char __user *buf, size_t count, loff_t *offset)
86 {
87 unsigned long *val = file->private_data;
88 return oprofilefs_ulong_to_user(*val, buf, count, offset);
89 }
90
91
92 static ssize_t ulong_write_file(struct file *file, char const __user *buf, size_t count, loff_t *offset)
93 {
94 unsigned long *value = file->private_data;
95 int retval;
96
97 if (*offset)
98 return -EINVAL;
99
100 retval = oprofilefs_ulong_from_user(value, buf, count);
101
102 if (retval)
103 return retval;
104 return count;
105 }
106
107
108 static int default_open(struct inode *inode, struct file *filp)
109 {
110 if (inode->i_private)
111 filp->private_data = inode->i_private;
112 return 0;
113 }
114
115
116 static const struct file_operations ulong_fops = {
117 .read = ulong_read_file,
118 .write = ulong_write_file,
119 .open = default_open,
120 };
121
122
123 static const struct file_operations ulong_ro_fops = {
124 .read = ulong_read_file,
125 .open = default_open,
126 };
127
128
129 static struct dentry *__oprofilefs_create_file(struct super_block *sb,
130 struct dentry *root, char const *name, const struct file_operations *fops,
131 int perm)
132 {
133 struct dentry *dentry;
134 struct inode *inode;
135
136 dentry = d_alloc_name(root, name);
137 if (!dentry)
138 return NULL;
139 inode = oprofilefs_get_inode(sb, S_IFREG | perm);
140 if (!inode) {
141 dput(dentry);
142 return NULL;
143 }
144 inode->i_fop = fops;
145 d_add(dentry, inode);
146 return dentry;
147 }
148
149
150 int oprofilefs_create_ulong(struct super_block *sb, struct dentry *root,
151 char const *name, unsigned long *val)
152 {
153 struct dentry *d = __oprofilefs_create_file(sb, root, name,
154 &ulong_fops, 0644);
155 if (!d)
156 return -EFAULT;
157
158 d->d_inode->i_private = val;
159 return 0;
160 }
161
162
163 int oprofilefs_create_ro_ulong(struct super_block *sb, struct dentry *root,
164 char const *name, unsigned long *val)
165 {
166 struct dentry *d = __oprofilefs_create_file(sb, root, name,
167 &ulong_ro_fops, 0444);
168 if (!d)
169 return -EFAULT;
170
171 d->d_inode->i_private = val;
172 return 0;
173 }
174
175
176 static ssize_t atomic_read_file(struct file *file, char __user *buf, size_t count, loff_t *offset)
177 {
178 atomic_t *val = file->private_data;
179 return oprofilefs_ulong_to_user(atomic_read(val), buf, count, offset);
180 }
181
182
183 static const struct file_operations atomic_ro_fops = {
184 .read = atomic_read_file,
185 .open = default_open,
186 };
187
188
189 int oprofilefs_create_ro_atomic(struct super_block *sb, struct dentry *root,
190 char const *name, atomic_t *val)
191 {
192 struct dentry *d = __oprofilefs_create_file(sb, root, name,
193 &atomic_ro_fops, 0444);
194 if (!d)
195 return -EFAULT;
196
197 d->d_inode->i_private = val;
198 return 0;
199 }
200
201
202 int oprofilefs_create_file(struct super_block *sb, struct dentry *root,
203 char const *name, const struct file_operations *fops)
204 {
205 if (!__oprofilefs_create_file(sb, root, name, fops, 0644))
206 return -EFAULT;
207 return 0;
208 }
209
210
211 int oprofilefs_create_file_perm(struct super_block *sb, struct dentry *root,
212 char const *name, const struct file_operations *fops, int perm)
213 {
214 if (!__oprofilefs_create_file(sb, root, name, fops, perm))
215 return -EFAULT;
216 return 0;
217 }
218
219
220 struct dentry *oprofilefs_mkdir(struct super_block *sb,
221 struct dentry *root, char const *name)
222 {
223 struct dentry *dentry;
224 struct inode *inode;
225
226 dentry = d_alloc_name(root, name);
227 if (!dentry)
228 return NULL;
229 inode = oprofilefs_get_inode(sb, S_IFDIR | 0755);
230 if (!inode) {
231 dput(dentry);
232 return NULL;
233 }
234 inode->i_op = &simple_dir_inode_operations;
235 inode->i_fop = &simple_dir_operations;
236 d_add(dentry, inode);
237 return dentry;
238 }
239
240
241 static int oprofilefs_fill_super(struct super_block *sb, void *data, int silent)
242 {
243 struct inode *root_inode;
244 struct dentry *root_dentry;
245
246 sb->s_blocksize = PAGE_CACHE_SIZE;
247 sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
248 sb->s_magic = OPROFILEFS_MAGIC;
249 sb->s_op = &s_ops;
250 sb->s_time_gran = 1;
251
252 root_inode = oprofilefs_get_inode(sb, S_IFDIR | 0755);
253 if (!root_inode)
254 return -ENOMEM;
255 root_inode->i_op = &simple_dir_inode_operations;
256 root_inode->i_fop = &simple_dir_operations;
257 root_dentry = d_alloc_root(root_inode);
258 if (!root_dentry) {
259 iput(root_inode);
260 return -ENOMEM;
261 }
262
263 sb->s_root = root_dentry;
264
265 oprofile_create_files(sb, root_dentry);
266
267 // FIXME: verify kill_litter_super removes our dentries
268 return 0;
269 }
270
271
272 static int oprofilefs_get_sb(struct file_system_type *fs_type,
273 int flags, const char *dev_name, void *data, struct vfsmount *mnt)
274 {
275 return get_sb_single(fs_type, flags, data, oprofilefs_fill_super, mnt);
276 }
277
278
279 static struct file_system_type oprofilefs_type = {
280 .owner = THIS_MODULE,
281 .name = "oprofilefs",
282 .get_sb = oprofilefs_get_sb,
283 .kill_sb = kill_litter_super,
284 };
285
286
287 int __init oprofilefs_register(void)
288 {
289 return register_filesystem(&oprofilefs_type);
290 }
291
292
293 void __exit oprofilefs_unregister(void)
294 {
295 unregister_filesystem(&oprofilefs_type);
296 }
297
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