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 | ||
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_uid = 0; | |
33 | inode->i_gid = 0; | |
34 | inode->i_blksize = PAGE_CACHE_SIZE; | |
35 | inode->i_blocks = 0; | |
36 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; | |
37 | } | |
38 | return inode; | |
39 | } | |
40 | ||
41 | ||
42 | static struct super_operations s_ops = { | |
43 | .statfs = simple_statfs, | |
44 | .drop_inode = generic_delete_inode, | |
45 | }; | |
46 | ||
47 | ||
48 | ssize_t oprofilefs_str_to_user(char const * str, char __user * buf, size_t count, loff_t * offset) | |
49 | { | |
50 | return simple_read_from_buffer(buf, count, offset, str, strlen(str)); | |
51 | } | |
52 | ||
53 | ||
54 | #define TMPBUFSIZE 50 | |
55 | ||
56 | ssize_t oprofilefs_ulong_to_user(unsigned long val, char __user * buf, size_t count, loff_t * offset) | |
57 | { | |
58 | char tmpbuf[TMPBUFSIZE]; | |
59 | size_t maxlen = snprintf(tmpbuf, TMPBUFSIZE, "%lu\n", val); | |
60 | if (maxlen > TMPBUFSIZE) | |
61 | maxlen = TMPBUFSIZE; | |
62 | return simple_read_from_buffer(buf, count, offset, tmpbuf, maxlen); | |
63 | } | |
64 | ||
65 | ||
66 | int oprofilefs_ulong_from_user(unsigned long * val, char const __user * buf, size_t count) | |
67 | { | |
68 | char tmpbuf[TMPBUFSIZE]; | |
69 | ||
70 | if (!count) | |
71 | return 0; | |
72 | ||
73 | if (count > TMPBUFSIZE - 1) | |
74 | return -EINVAL; | |
75 | ||
76 | memset(tmpbuf, 0x0, TMPBUFSIZE); | |
77 | ||
78 | if (copy_from_user(tmpbuf, buf, count)) | |
79 | return -EFAULT; | |
80 | ||
81 | spin_lock(&oprofilefs_lock); | |
82 | *val = simple_strtoul(tmpbuf, NULL, 0); | |
83 | spin_unlock(&oprofilefs_lock); | |
84 | return 0; | |
85 | } | |
86 | ||
87 | ||
88 | static ssize_t ulong_read_file(struct file * file, char __user * buf, size_t count, loff_t * offset) | |
89 | { | |
90 | unsigned long * val = file->private_data; | |
91 | return oprofilefs_ulong_to_user(*val, buf, count, offset); | |
92 | } | |
93 | ||
94 | ||
95 | static ssize_t ulong_write_file(struct file * file, char const __user * buf, size_t count, loff_t * offset) | |
96 | { | |
97 | unsigned long * value = file->private_data; | |
98 | int retval; | |
99 | ||
100 | if (*offset) | |
101 | return -EINVAL; | |
102 | ||
103 | retval = oprofilefs_ulong_from_user(value, buf, count); | |
104 | ||
105 | if (retval) | |
106 | return retval; | |
107 | return count; | |
108 | } | |
109 | ||
110 | ||
111 | static int default_open(struct inode * inode, struct file * filp) | |
112 | { | |
113 | if (inode->u.generic_ip) | |
114 | filp->private_data = inode->u.generic_ip; | |
115 | return 0; | |
116 | } | |
117 | ||
118 | ||
119 | static struct file_operations ulong_fops = { | |
120 | .read = ulong_read_file, | |
121 | .write = ulong_write_file, | |
122 | .open = default_open, | |
123 | }; | |
124 | ||
125 | ||
126 | static struct file_operations ulong_ro_fops = { | |
127 | .read = ulong_read_file, | |
128 | .open = default_open, | |
129 | }; | |
130 | ||
131 | ||
132 | static struct dentry * __oprofilefs_create_file(struct super_block * sb, | |
99ac48f5 | 133 | struct dentry * root, char const * name, const struct file_operations * fops, |
1da177e4 LT |
134 | int perm) |
135 | { | |
136 | struct dentry * dentry; | |
137 | struct inode * inode; | |
138 | ||
139 | dentry = d_alloc_name(root, name); | |
140 | if (!dentry) | |
141 | return NULL; | |
142 | inode = oprofilefs_get_inode(sb, S_IFREG | perm); | |
143 | if (!inode) { | |
144 | dput(dentry); | |
145 | return NULL; | |
146 | } | |
147 | inode->i_fop = fops; | |
148 | d_add(dentry, inode); | |
149 | return dentry; | |
150 | } | |
151 | ||
152 | ||
153 | int oprofilefs_create_ulong(struct super_block * sb, struct dentry * root, | |
154 | char const * name, unsigned long * val) | |
155 | { | |
156 | struct dentry * d = __oprofilefs_create_file(sb, root, name, | |
157 | &ulong_fops, 0644); | |
158 | if (!d) | |
159 | return -EFAULT; | |
160 | ||
161 | d->d_inode->u.generic_ip = val; | |
162 | return 0; | |
163 | } | |
164 | ||
165 | ||
166 | int oprofilefs_create_ro_ulong(struct super_block * sb, struct dentry * root, | |
167 | char const * name, unsigned long * val) | |
168 | { | |
169 | struct dentry * d = __oprofilefs_create_file(sb, root, name, | |
170 | &ulong_ro_fops, 0444); | |
171 | if (!d) | |
172 | return -EFAULT; | |
173 | ||
174 | d->d_inode->u.generic_ip = val; | |
175 | return 0; | |
176 | } | |
177 | ||
178 | ||
179 | static ssize_t atomic_read_file(struct file * file, char __user * buf, size_t count, loff_t * offset) | |
180 | { | |
181 | atomic_t * val = file->private_data; | |
182 | return oprofilefs_ulong_to_user(atomic_read(val), buf, count, offset); | |
183 | } | |
184 | ||
185 | ||
186 | static struct file_operations atomic_ro_fops = { | |
187 | .read = atomic_read_file, | |
188 | .open = default_open, | |
189 | }; | |
190 | ||
191 | ||
192 | int oprofilefs_create_ro_atomic(struct super_block * sb, struct dentry * root, | |
193 | char const * name, atomic_t * val) | |
194 | { | |
195 | struct dentry * d = __oprofilefs_create_file(sb, root, name, | |
196 | &atomic_ro_fops, 0444); | |
197 | if (!d) | |
198 | return -EFAULT; | |
199 | ||
200 | d->d_inode->u.generic_ip = val; | |
201 | return 0; | |
202 | } | |
203 | ||
204 | ||
205 | int oprofilefs_create_file(struct super_block * sb, struct dentry * root, | |
99ac48f5 | 206 | char const * name, const struct file_operations * fops) |
1da177e4 LT |
207 | { |
208 | if (!__oprofilefs_create_file(sb, root, name, fops, 0644)) | |
209 | return -EFAULT; | |
210 | return 0; | |
211 | } | |
212 | ||
213 | ||
214 | int oprofilefs_create_file_perm(struct super_block * sb, struct dentry * root, | |
99ac48f5 | 215 | char const * name, const struct file_operations * fops, int perm) |
1da177e4 LT |
216 | { |
217 | if (!__oprofilefs_create_file(sb, root, name, fops, perm)) | |
218 | return -EFAULT; | |
219 | return 0; | |
220 | } | |
221 | ||
222 | ||
223 | struct dentry * oprofilefs_mkdir(struct super_block * sb, | |
224 | struct dentry * root, char const * name) | |
225 | { | |
226 | struct dentry * dentry; | |
227 | struct inode * inode; | |
228 | ||
229 | dentry = d_alloc_name(root, name); | |
230 | if (!dentry) | |
231 | return NULL; | |
232 | inode = oprofilefs_get_inode(sb, S_IFDIR | 0755); | |
233 | if (!inode) { | |
234 | dput(dentry); | |
235 | return NULL; | |
236 | } | |
237 | inode->i_op = &simple_dir_inode_operations; | |
238 | inode->i_fop = &simple_dir_operations; | |
239 | d_add(dentry, inode); | |
240 | return dentry; | |
241 | } | |
242 | ||
243 | ||
244 | static int oprofilefs_fill_super(struct super_block * sb, void * data, int silent) | |
245 | { | |
246 | struct inode * root_inode; | |
247 | struct dentry * root_dentry; | |
248 | ||
249 | sb->s_blocksize = PAGE_CACHE_SIZE; | |
250 | sb->s_blocksize_bits = PAGE_CACHE_SHIFT; | |
251 | sb->s_magic = OPROFILEFS_MAGIC; | |
252 | sb->s_op = &s_ops; | |
253 | sb->s_time_gran = 1; | |
254 | ||
255 | root_inode = oprofilefs_get_inode(sb, S_IFDIR | 0755); | |
256 | if (!root_inode) | |
257 | return -ENOMEM; | |
258 | root_inode->i_op = &simple_dir_inode_operations; | |
259 | root_inode->i_fop = &simple_dir_operations; | |
260 | root_dentry = d_alloc_root(root_inode); | |
261 | if (!root_dentry) { | |
262 | iput(root_inode); | |
263 | return -ENOMEM; | |
264 | } | |
265 | ||
266 | sb->s_root = root_dentry; | |
267 | ||
268 | oprofile_create_files(sb, root_dentry); | |
269 | ||
270 | // FIXME: verify kill_litter_super removes our dentries | |
271 | return 0; | |
272 | } | |
273 | ||
274 | ||
275 | static struct super_block *oprofilefs_get_sb(struct file_system_type *fs_type, | |
276 | int flags, const char *dev_name, void *data) | |
277 | { | |
278 | return get_sb_single(fs_type, flags, data, oprofilefs_fill_super); | |
279 | } | |
280 | ||
281 | ||
282 | static struct file_system_type oprofilefs_type = { | |
283 | .owner = THIS_MODULE, | |
284 | .name = "oprofilefs", | |
285 | .get_sb = oprofilefs_get_sb, | |
286 | .kill_sb = kill_litter_super, | |
287 | }; | |
288 | ||
289 | ||
290 | int __init oprofilefs_register(void) | |
291 | { | |
292 | return register_filesystem(&oprofilefs_type); | |
293 | } | |
294 | ||
295 | ||
296 | void __exit oprofilefs_unregister(void) | |
297 | { | |
298 | unregister_filesystem(&oprofilefs_type); | |
299 | } |