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Commit | Line | Data |
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1da177e4 LT |
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 | ||
2d21a29f | 24 | DEFINE_RAW_SPINLOCK(oprofilefs_lock); |
1da177e4 | 25 | |
25ad2913 | 26 | static struct inode *oprofilefs_get_inode(struct super_block *sb, int mode) |
1da177e4 | 27 | { |
25ad2913 | 28 | struct inode *inode = new_inode(sb); |
1da177e4 LT |
29 | |
30 | if (inode) { | |
85fe4025 | 31 | inode->i_ino = get_next_ino(); |
1da177e4 | 32 | inode->i_mode = mode; |
1da177e4 LT |
33 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; |
34 | } | |
35 | return inode; | |
36 | } | |
37 | ||
38 | ||
b87221de | 39 | static const struct super_operations s_ops = { |
1da177e4 LT |
40 | .statfs = simple_statfs, |
41 | .drop_inode = generic_delete_inode, | |
42 | }; | |
43 | ||
44 | ||
25ad2913 | 45 | ssize_t oprofilefs_str_to_user(char const *str, char __user *buf, size_t count, loff_t *offset) |
1da177e4 LT |
46 | { |
47 | return simple_read_from_buffer(buf, count, offset, str, strlen(str)); | |
48 | } | |
49 | ||
50 | ||
51 | #define TMPBUFSIZE 50 | |
52 | ||
25ad2913 | 53 | ssize_t oprofilefs_ulong_to_user(unsigned long val, char __user *buf, size_t count, loff_t *offset) |
1da177e4 LT |
54 | { |
55 | char tmpbuf[TMPBUFSIZE]; | |
56 | size_t maxlen = snprintf(tmpbuf, TMPBUFSIZE, "%lu\n", val); | |
57 | if (maxlen > TMPBUFSIZE) | |
58 | maxlen = TMPBUFSIZE; | |
59 | return simple_read_from_buffer(buf, count, offset, tmpbuf, maxlen); | |
60 | } | |
61 | ||
62 | ||
913050b9 RR |
63 | /* |
64 | * Note: If oprofilefs_ulong_from_user() returns 0, then *val remains | |
65 | * unchanged and might be uninitialized. This follows write syscall | |
66 | * implementation when count is zero: "If count is zero ... [and if] | |
67 | * no errors are detected, 0 will be returned without causing any | |
68 | * other effect." (man 2 write) | |
69 | */ | |
25ad2913 | 70 | int oprofilefs_ulong_from_user(unsigned long *val, char const __user *buf, size_t count) |
1da177e4 LT |
71 | { |
72 | char tmpbuf[TMPBUFSIZE]; | |
4dfc896e | 73 | unsigned long flags; |
1da177e4 LT |
74 | |
75 | if (!count) | |
76 | return 0; | |
77 | ||
78 | if (count > TMPBUFSIZE - 1) | |
79 | return -EINVAL; | |
80 | ||
81 | memset(tmpbuf, 0x0, TMPBUFSIZE); | |
82 | ||
83 | if (copy_from_user(tmpbuf, buf, count)) | |
84 | return -EFAULT; | |
85 | ||
2d21a29f | 86 | raw_spin_lock_irqsave(&oprofilefs_lock, flags); |
1da177e4 | 87 | *val = simple_strtoul(tmpbuf, NULL, 0); |
2d21a29f | 88 | raw_spin_unlock_irqrestore(&oprofilefs_lock, flags); |
913050b9 | 89 | return count; |
1da177e4 LT |
90 | } |
91 | ||
92 | ||
25ad2913 | 93 | static ssize_t ulong_read_file(struct file *file, char __user *buf, size_t count, loff_t *offset) |
1da177e4 | 94 | { |
25ad2913 | 95 | unsigned long *val = file->private_data; |
1da177e4 LT |
96 | return oprofilefs_ulong_to_user(*val, buf, count, offset); |
97 | } | |
98 | ||
99 | ||
25ad2913 | 100 | static ssize_t ulong_write_file(struct file *file, char const __user *buf, size_t count, loff_t *offset) |
1da177e4 | 101 | { |
7df01d96 | 102 | unsigned long value; |
1da177e4 LT |
103 | int retval; |
104 | ||
105 | if (*offset) | |
106 | return -EINVAL; | |
107 | ||
7df01d96 | 108 | retval = oprofilefs_ulong_from_user(&value, buf, count); |
913050b9 | 109 | if (retval <= 0) |
7df01d96 | 110 | return retval; |
1da177e4 | 111 | |
7df01d96 | 112 | retval = oprofile_set_ulong(file->private_data, value); |
1da177e4 LT |
113 | if (retval) |
114 | return retval; | |
7df01d96 | 115 | |
1da177e4 LT |
116 | return count; |
117 | } | |
118 | ||
119 | ||
d54b1fdb | 120 | static const struct file_operations ulong_fops = { |
1da177e4 LT |
121 | .read = ulong_read_file, |
122 | .write = ulong_write_file, | |
234e3405 | 123 | .open = simple_open, |
6038f373 | 124 | .llseek = default_llseek, |
1da177e4 LT |
125 | }; |
126 | ||
127 | ||
d54b1fdb | 128 | static const struct file_operations ulong_ro_fops = { |
1da177e4 | 129 | .read = ulong_read_file, |
234e3405 | 130 | .open = simple_open, |
6038f373 | 131 | .llseek = default_llseek, |
1da177e4 LT |
132 | }; |
133 | ||
134 | ||
4fdaa7b6 | 135 | static int __oprofilefs_create_file(struct super_block *sb, |
25ad2913 | 136 | struct dentry *root, char const *name, const struct file_operations *fops, |
4fdaa7b6 | 137 | int perm, void *priv) |
1da177e4 | 138 | { |
25ad2913 RR |
139 | struct dentry *dentry; |
140 | struct inode *inode; | |
1da177e4 LT |
141 | |
142 | dentry = d_alloc_name(root, name); | |
143 | if (!dentry) | |
4fdaa7b6 | 144 | return -ENOMEM; |
1da177e4 LT |
145 | inode = oprofilefs_get_inode(sb, S_IFREG | perm); |
146 | if (!inode) { | |
147 | dput(dentry); | |
4fdaa7b6 | 148 | return -ENOMEM; |
1da177e4 LT |
149 | } |
150 | inode->i_fop = fops; | |
151 | d_add(dentry, inode); | |
4fdaa7b6 RR |
152 | dentry->d_inode->i_private = priv; |
153 | return 0; | |
1da177e4 LT |
154 | } |
155 | ||
156 | ||
25ad2913 RR |
157 | int oprofilefs_create_ulong(struct super_block *sb, struct dentry *root, |
158 | char const *name, unsigned long *val) | |
1da177e4 | 159 | { |
4fdaa7b6 RR |
160 | return __oprofilefs_create_file(sb, root, name, |
161 | &ulong_fops, 0644, val); | |
1da177e4 LT |
162 | } |
163 | ||
164 | ||
25ad2913 RR |
165 | int oprofilefs_create_ro_ulong(struct super_block *sb, struct dentry *root, |
166 | char const *name, unsigned long *val) | |
1da177e4 | 167 | { |
4fdaa7b6 RR |
168 | return __oprofilefs_create_file(sb, root, name, |
169 | &ulong_ro_fops, 0444, val); | |
1da177e4 LT |
170 | } |
171 | ||
172 | ||
25ad2913 | 173 | static ssize_t atomic_read_file(struct file *file, char __user *buf, size_t count, loff_t *offset) |
1da177e4 | 174 | { |
25ad2913 | 175 | atomic_t *val = file->private_data; |
1da177e4 LT |
176 | return oprofilefs_ulong_to_user(atomic_read(val), buf, count, offset); |
177 | } | |
6a18037d | 178 | |
1da177e4 | 179 | |
d54b1fdb | 180 | static const struct file_operations atomic_ro_fops = { |
1da177e4 | 181 | .read = atomic_read_file, |
234e3405 | 182 | .open = simple_open, |
6038f373 | 183 | .llseek = default_llseek, |
1da177e4 | 184 | }; |
6a18037d | 185 | |
1da177e4 | 186 | |
25ad2913 RR |
187 | int oprofilefs_create_ro_atomic(struct super_block *sb, struct dentry *root, |
188 | char const *name, atomic_t *val) | |
1da177e4 | 189 | { |
4fdaa7b6 RR |
190 | return __oprofilefs_create_file(sb, root, name, |
191 | &atomic_ro_fops, 0444, val); | |
1da177e4 LT |
192 | } |
193 | ||
6a18037d | 194 | |
25ad2913 RR |
195 | int oprofilefs_create_file(struct super_block *sb, struct dentry *root, |
196 | char const *name, const struct file_operations *fops) | |
1da177e4 | 197 | { |
4fdaa7b6 | 198 | return __oprofilefs_create_file(sb, root, name, fops, 0644, NULL); |
1da177e4 LT |
199 | } |
200 | ||
201 | ||
25ad2913 RR |
202 | int oprofilefs_create_file_perm(struct super_block *sb, struct dentry *root, |
203 | char const *name, const struct file_operations *fops, int perm) | |
1da177e4 | 204 | { |
4fdaa7b6 | 205 | return __oprofilefs_create_file(sb, root, name, fops, perm, NULL); |
1da177e4 LT |
206 | } |
207 | ||
208 | ||
25ad2913 RR |
209 | struct dentry *oprofilefs_mkdir(struct super_block *sb, |
210 | struct dentry *root, char const *name) | |
1da177e4 | 211 | { |
25ad2913 RR |
212 | struct dentry *dentry; |
213 | struct inode *inode; | |
1da177e4 LT |
214 | |
215 | dentry = d_alloc_name(root, name); | |
216 | if (!dentry) | |
217 | return NULL; | |
218 | inode = oprofilefs_get_inode(sb, S_IFDIR | 0755); | |
219 | if (!inode) { | |
220 | dput(dentry); | |
221 | return NULL; | |
222 | } | |
223 | inode->i_op = &simple_dir_inode_operations; | |
224 | inode->i_fop = &simple_dir_operations; | |
225 | d_add(dentry, inode); | |
226 | return dentry; | |
227 | } | |
228 | ||
229 | ||
25ad2913 | 230 | static int oprofilefs_fill_super(struct super_block *sb, void *data, int silent) |
1da177e4 | 231 | { |
25ad2913 | 232 | struct inode *root_inode; |
1da177e4 LT |
233 | |
234 | sb->s_blocksize = PAGE_CACHE_SIZE; | |
235 | sb->s_blocksize_bits = PAGE_CACHE_SHIFT; | |
236 | sb->s_magic = OPROFILEFS_MAGIC; | |
237 | sb->s_op = &s_ops; | |
238 | sb->s_time_gran = 1; | |
239 | ||
240 | root_inode = oprofilefs_get_inode(sb, S_IFDIR | 0755); | |
241 | if (!root_inode) | |
242 | return -ENOMEM; | |
243 | root_inode->i_op = &simple_dir_inode_operations; | |
244 | root_inode->i_fop = &simple_dir_operations; | |
318ceed0 AV |
245 | sb->s_root = d_make_root(root_inode); |
246 | if (!sb->s_root) | |
1da177e4 | 247 | return -ENOMEM; |
1da177e4 | 248 | |
318ceed0 | 249 | oprofile_create_files(sb, sb->s_root); |
1da177e4 LT |
250 | |
251 | // FIXME: verify kill_litter_super removes our dentries | |
252 | return 0; | |
253 | } | |
254 | ||
255 | ||
fc14f2fe AV |
256 | static struct dentry *oprofilefs_mount(struct file_system_type *fs_type, |
257 | int flags, const char *dev_name, void *data) | |
1da177e4 | 258 | { |
fc14f2fe | 259 | return mount_single(fs_type, flags, data, oprofilefs_fill_super); |
1da177e4 LT |
260 | } |
261 | ||
262 | ||
263 | static struct file_system_type oprofilefs_type = { | |
264 | .owner = THIS_MODULE, | |
265 | .name = "oprofilefs", | |
fc14f2fe | 266 | .mount = oprofilefs_mount, |
1da177e4 LT |
267 | .kill_sb = kill_litter_super, |
268 | }; | |
269 | ||
270 | ||
271 | int __init oprofilefs_register(void) | |
272 | { | |
273 | return register_filesystem(&oprofilefs_type); | |
274 | } | |
275 | ||
276 | ||
277 | void __exit oprofilefs_unregister(void) | |
278 | { | |
279 | unregister_filesystem(&oprofilefs_type); | |
280 | } |