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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_RAW_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_ino = get_next_ino(); | |
32 | inode->i_mode = mode; | |
33 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; | |
34 | } | |
35 | return inode; | |
36 | } | |
37 | ||
38 | ||
39 | static const struct super_operations s_ops = { | |
40 | .statfs = simple_statfs, | |
41 | .drop_inode = generic_delete_inode, | |
42 | }; | |
43 | ||
44 | ||
45 | ssize_t oprofilefs_str_to_user(char const *str, char __user *buf, size_t count, loff_t *offset) | |
46 | { | |
47 | return simple_read_from_buffer(buf, count, offset, str, strlen(str)); | |
48 | } | |
49 | ||
50 | ||
51 | #define TMPBUFSIZE 50 | |
52 | ||
53 | ssize_t oprofilefs_ulong_to_user(unsigned long val, char __user *buf, size_t count, loff_t *offset) | |
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 | ||
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 | */ | |
70 | int oprofilefs_ulong_from_user(unsigned long *val, char const __user *buf, size_t count) | |
71 | { | |
72 | char tmpbuf[TMPBUFSIZE]; | |
73 | unsigned long flags; | |
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 | ||
86 | raw_spin_lock_irqsave(&oprofilefs_lock, flags); | |
87 | *val = simple_strtoul(tmpbuf, NULL, 0); | |
88 | raw_spin_unlock_irqrestore(&oprofilefs_lock, flags); | |
89 | return count; | |
90 | } | |
91 | ||
92 | ||
93 | static ssize_t ulong_read_file(struct file *file, char __user *buf, size_t count, loff_t *offset) | |
94 | { | |
95 | unsigned long *val = file->private_data; | |
96 | return oprofilefs_ulong_to_user(*val, buf, count, offset); | |
97 | } | |
98 | ||
99 | ||
100 | static ssize_t ulong_write_file(struct file *file, char const __user *buf, size_t count, loff_t *offset) | |
101 | { | |
102 | unsigned long value; | |
103 | int retval; | |
104 | ||
105 | if (*offset) | |
106 | return -EINVAL; | |
107 | ||
108 | retval = oprofilefs_ulong_from_user(&value, buf, count); | |
109 | if (retval <= 0) | |
110 | return retval; | |
111 | ||
112 | retval = oprofile_set_ulong(file->private_data, value); | |
113 | if (retval) | |
114 | return retval; | |
115 | ||
116 | return count; | |
117 | } | |
118 | ||
119 | ||
120 | static const struct file_operations ulong_fops = { | |
121 | .read = ulong_read_file, | |
122 | .write = ulong_write_file, | |
123 | .open = simple_open, | |
124 | .llseek = default_llseek, | |
125 | }; | |
126 | ||
127 | ||
128 | static const struct file_operations ulong_ro_fops = { | |
129 | .read = ulong_read_file, | |
130 | .open = simple_open, | |
131 | .llseek = default_llseek, | |
132 | }; | |
133 | ||
134 | ||
135 | static int __oprofilefs_create_file(struct dentry *root, char const *name, | |
136 | const struct file_operations *fops, int perm, void *priv) | |
137 | { | |
138 | struct dentry *dentry; | |
139 | struct inode *inode; | |
140 | ||
141 | inode_lock(d_inode(root)); | |
142 | dentry = d_alloc_name(root, name); | |
143 | if (!dentry) { | |
144 | inode_unlock(d_inode(root)); | |
145 | return -ENOMEM; | |
146 | } | |
147 | inode = oprofilefs_get_inode(root->d_sb, S_IFREG | perm); | |
148 | if (!inode) { | |
149 | dput(dentry); | |
150 | inode_unlock(d_inode(root)); | |
151 | return -ENOMEM; | |
152 | } | |
153 | inode->i_fop = fops; | |
154 | inode->i_private = priv; | |
155 | d_add(dentry, inode); | |
156 | inode_unlock(d_inode(root)); | |
157 | return 0; | |
158 | } | |
159 | ||
160 | ||
161 | int oprofilefs_create_ulong(struct dentry *root, | |
162 | char const *name, unsigned long *val) | |
163 | { | |
164 | return __oprofilefs_create_file(root, name, | |
165 | &ulong_fops, 0644, val); | |
166 | } | |
167 | ||
168 | ||
169 | int oprofilefs_create_ro_ulong(struct dentry *root, | |
170 | char const *name, unsigned long *val) | |
171 | { | |
172 | return __oprofilefs_create_file(root, name, | |
173 | &ulong_ro_fops, 0444, val); | |
174 | } | |
175 | ||
176 | ||
177 | static ssize_t atomic_read_file(struct file *file, char __user *buf, size_t count, loff_t *offset) | |
178 | { | |
179 | atomic_t *val = file->private_data; | |
180 | return oprofilefs_ulong_to_user(atomic_read(val), buf, count, offset); | |
181 | } | |
182 | ||
183 | ||
184 | static const struct file_operations atomic_ro_fops = { | |
185 | .read = atomic_read_file, | |
186 | .open = simple_open, | |
187 | .llseek = default_llseek, | |
188 | }; | |
189 | ||
190 | ||
191 | int oprofilefs_create_ro_atomic(struct dentry *root, | |
192 | char const *name, atomic_t *val) | |
193 | { | |
194 | return __oprofilefs_create_file(root, name, | |
195 | &atomic_ro_fops, 0444, val); | |
196 | } | |
197 | ||
198 | ||
199 | int oprofilefs_create_file(struct dentry *root, | |
200 | char const *name, const struct file_operations *fops) | |
201 | { | |
202 | return __oprofilefs_create_file(root, name, fops, 0644, NULL); | |
203 | } | |
204 | ||
205 | ||
206 | int oprofilefs_create_file_perm(struct dentry *root, | |
207 | char const *name, const struct file_operations *fops, int perm) | |
208 | { | |
209 | return __oprofilefs_create_file(root, name, fops, perm, NULL); | |
210 | } | |
211 | ||
212 | ||
213 | struct dentry *oprofilefs_mkdir(struct dentry *parent, char const *name) | |
214 | { | |
215 | struct dentry *dentry; | |
216 | struct inode *inode; | |
217 | ||
218 | inode_lock(d_inode(parent)); | |
219 | dentry = d_alloc_name(parent, name); | |
220 | if (!dentry) { | |
221 | inode_unlock(d_inode(parent)); | |
222 | return NULL; | |
223 | } | |
224 | inode = oprofilefs_get_inode(parent->d_sb, S_IFDIR | 0755); | |
225 | if (!inode) { | |
226 | dput(dentry); | |
227 | inode_unlock(d_inode(parent)); | |
228 | return NULL; | |
229 | } | |
230 | inode->i_op = &simple_dir_inode_operations; | |
231 | inode->i_fop = &simple_dir_operations; | |
232 | d_add(dentry, inode); | |
233 | inode_unlock(d_inode(parent)); | |
234 | return dentry; | |
235 | } | |
236 | ||
237 | ||
238 | static int oprofilefs_fill_super(struct super_block *sb, void *data, int silent) | |
239 | { | |
240 | struct inode *root_inode; | |
241 | ||
242 | sb->s_blocksize = PAGE_SIZE; | |
243 | sb->s_blocksize_bits = PAGE_SHIFT; | |
244 | sb->s_magic = OPROFILEFS_MAGIC; | |
245 | sb->s_op = &s_ops; | |
246 | sb->s_time_gran = 1; | |
247 | ||
248 | root_inode = oprofilefs_get_inode(sb, S_IFDIR | 0755); | |
249 | if (!root_inode) | |
250 | return -ENOMEM; | |
251 | root_inode->i_op = &simple_dir_inode_operations; | |
252 | root_inode->i_fop = &simple_dir_operations; | |
253 | sb->s_root = d_make_root(root_inode); | |
254 | if (!sb->s_root) | |
255 | return -ENOMEM; | |
256 | ||
257 | oprofile_create_files(sb->s_root); | |
258 | ||
259 | // FIXME: verify kill_litter_super removes our dentries | |
260 | return 0; | |
261 | } | |
262 | ||
263 | ||
264 | static struct dentry *oprofilefs_mount(struct file_system_type *fs_type, | |
265 | int flags, const char *dev_name, void *data) | |
266 | { | |
267 | return mount_single(fs_type, flags, data, oprofilefs_fill_super); | |
268 | } | |
269 | ||
270 | ||
271 | static struct file_system_type oprofilefs_type = { | |
272 | .owner = THIS_MODULE, | |
273 | .name = "oprofilefs", | |
274 | .mount = oprofilefs_mount, | |
275 | .kill_sb = kill_litter_super, | |
276 | }; | |
277 | MODULE_ALIAS_FS("oprofilefs"); | |
278 | ||
279 | ||
280 | int __init oprofilefs_register(void) | |
281 | { | |
282 | return register_filesystem(&oprofilefs_type); | |
283 | } | |
284 | ||
285 | ||
286 | void __exit oprofilefs_unregister(void) | |
287 | { | |
288 | unregister_filesystem(&oprofilefs_type); | |
289 | } |