Merge branch 'llseek' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/bkl
[linux-2.6.git] / drivers / oprofile / oprofilefs.c
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 const 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;
95         int retval;
96
97         if (*offset)
98                 return -EINVAL;
99
100         retval = oprofilefs_ulong_from_user(&value, buf, count);
101         if (retval)
102                 return retval;
103
104         retval = oprofile_set_ulong(file->private_data, value);
105         if (retval)
106                 return retval;
107
108         return count;
109 }
110
111
112 static int default_open(struct inode *inode, struct file *filp)
113 {
114         if (inode->i_private)
115                 filp->private_data = inode->i_private;
116         return 0;
117 }
118
119
120 static const struct file_operations ulong_fops = {
121         .read           = ulong_read_file,
122         .write          = ulong_write_file,
123         .open           = default_open,
124         .llseek         = default_llseek,
125 };
126
127
128 static const struct file_operations ulong_ro_fops = {
129         .read           = ulong_read_file,
130         .open           = default_open,
131         .llseek         = default_llseek,
132 };
133
134
135 static int __oprofilefs_create_file(struct super_block *sb,
136         struct dentry *root, char const *name, const struct file_operations *fops,
137         int perm, void *priv)
138 {
139         struct dentry *dentry;
140         struct inode *inode;
141
142         dentry = d_alloc_name(root, name);
143         if (!dentry)
144                 return -ENOMEM;
145         inode = oprofilefs_get_inode(sb, S_IFREG | perm);
146         if (!inode) {
147                 dput(dentry);
148                 return -ENOMEM;
149         }
150         inode->i_fop = fops;
151         d_add(dentry, inode);
152         dentry->d_inode->i_private = priv;
153         return 0;
154 }
155
156
157 int oprofilefs_create_ulong(struct super_block *sb, struct dentry *root,
158         char const *name, unsigned long *val)
159 {
160         return __oprofilefs_create_file(sb, root, name,
161                                         &ulong_fops, 0644, val);
162 }
163
164
165 int oprofilefs_create_ro_ulong(struct super_block *sb, struct dentry *root,
166         char const *name, unsigned long *val)
167 {
168         return __oprofilefs_create_file(sb, root, name,
169                                         &ulong_ro_fops, 0444, val);
170 }
171
172
173 static ssize_t atomic_read_file(struct file *file, char __user *buf, size_t count, loff_t *offset)
174 {
175         atomic_t *val = file->private_data;
176         return oprofilefs_ulong_to_user(atomic_read(val), buf, count, offset);
177 }
178
179
180 static const struct file_operations atomic_ro_fops = {
181         .read           = atomic_read_file,
182         .open           = default_open,
183         .llseek         = default_llseek,
184 };
185
186
187 int oprofilefs_create_ro_atomic(struct super_block *sb, struct dentry *root,
188         char const *name, atomic_t *val)
189 {
190         return __oprofilefs_create_file(sb, root, name,
191                                         &atomic_ro_fops, 0444, val);
192 }
193
194
195 int oprofilefs_create_file(struct super_block *sb, struct dentry *root,
196         char const *name, const struct file_operations *fops)
197 {
198         return __oprofilefs_create_file(sb, root, name, fops, 0644, NULL);
199 }
200
201
202 int oprofilefs_create_file_perm(struct super_block *sb, struct dentry *root,
203         char const *name, const struct file_operations *fops, int perm)
204 {
205         return __oprofilefs_create_file(sb, root, name, fops, perm, NULL);
206 }
207
208
209 struct dentry *oprofilefs_mkdir(struct super_block *sb,
210         struct dentry *root, char const *name)
211 {
212         struct dentry *dentry;
213         struct inode *inode;
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
230 static int oprofilefs_fill_super(struct super_block *sb, void *data, int silent)
231 {
232         struct inode *root_inode;
233         struct dentry *root_dentry;
234
235         sb->s_blocksize = PAGE_CACHE_SIZE;
236         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
237         sb->s_magic = OPROFILEFS_MAGIC;
238         sb->s_op = &s_ops;
239         sb->s_time_gran = 1;
240
241         root_inode = oprofilefs_get_inode(sb, S_IFDIR | 0755);
242         if (!root_inode)
243                 return -ENOMEM;
244         root_inode->i_op = &simple_dir_inode_operations;
245         root_inode->i_fop = &simple_dir_operations;
246         root_dentry = d_alloc_root(root_inode);
247         if (!root_dentry) {
248                 iput(root_inode);
249                 return -ENOMEM;
250         }
251
252         sb->s_root = root_dentry;
253
254         oprofile_create_files(sb, root_dentry);
255
256         // FIXME: verify kill_litter_super removes our dentries
257         return 0;
258 }
259
260
261 static int oprofilefs_get_sb(struct file_system_type *fs_type,
262         int flags, const char *dev_name, void *data, struct vfsmount *mnt)
263 {
264         return get_sb_single(fs_type, flags, data, oprofilefs_fill_super, mnt);
265 }
266
267
268 static struct file_system_type oprofilefs_type = {
269         .owner          = THIS_MODULE,
270         .name           = "oprofilefs",
271         .get_sb         = oprofilefs_get_sb,
272         .kill_sb        = kill_litter_super,
273 };
274
275
276 int __init oprofilefs_register(void)
277 {
278         return register_filesystem(&oprofilefs_type);
279 }
280
281
282 void __exit oprofilefs_unregister(void)
283 {
284         unregister_filesystem(&oprofilefs_type);
285 }