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Jon Medhurstaaf37a32013-06-11 12:10:56 +01001/**
2 * @file gatorfs.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/fs.h>
16#include <linux/pagemap.h>
Jon Medhurst96b56152014-10-30 18:01:15 +000017#include <linux/uaccess.h>
Jon Medhurstaaf37a32013-06-11 12:10:56 +010018
19#define gatorfs_MAGIC 0x24051020
20#define TMPBUFSIZE 50
21DEFINE_SPINLOCK(gatorfs_lock);
22
23static struct inode *gatorfs_get_inode(struct super_block *sb, int mode)
24{
25 struct inode *inode = new_inode(sb);
26
27 if (inode) {
28#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 37)
29 inode->i_ino = get_next_ino();
30#endif
31 inode->i_mode = mode;
32 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
33 }
34 return inode;
35}
36
37static const struct super_operations s_ops = {
38 .statfs = simple_statfs,
39 .drop_inode = generic_delete_inode,
40};
41
Jon Medhurst15ce78d2014-04-10 09:02:02 +010042static ssize_t gatorfs_ulong_to_user(unsigned long val, char __user *buf, size_t count, loff_t *offset)
Jon Medhurstaaf37a32013-06-11 12:10:56 +010043{
44 char tmpbuf[TMPBUFSIZE];
45 size_t maxlen = snprintf(tmpbuf, TMPBUFSIZE, "%lu\n", val);
Jon Medhurst96b56152014-10-30 18:01:15 +000046
Jon Medhurstaaf37a32013-06-11 12:10:56 +010047 if (maxlen > TMPBUFSIZE)
48 maxlen = TMPBUFSIZE;
49 return simple_read_from_buffer(buf, count, offset, tmpbuf, maxlen);
50}
51
Jon Medhurst15ce78d2014-04-10 09:02:02 +010052static ssize_t gatorfs_u64_to_user(u64 val, char __user *buf, size_t count, loff_t *offset)
Jon Medhurstaaf37a32013-06-11 12:10:56 +010053{
54 char tmpbuf[TMPBUFSIZE];
55 size_t maxlen = snprintf(tmpbuf, TMPBUFSIZE, "%llu\n", val);
Jon Medhurst96b56152014-10-30 18:01:15 +000056
Jon Medhurstaaf37a32013-06-11 12:10:56 +010057 if (maxlen > TMPBUFSIZE)
58 maxlen = TMPBUFSIZE;
59 return simple_read_from_buffer(buf, count, offset, tmpbuf, maxlen);
60}
61
Jon Medhurst15ce78d2014-04-10 09:02:02 +010062static int gatorfs_ulong_from_user(unsigned long *val, char const __user *buf, size_t count)
Jon Medhurstaaf37a32013-06-11 12:10:56 +010063{
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(&gatorfs_lock, flags);
79 *val = simple_strtoul(tmpbuf, NULL, 0);
80 spin_unlock_irqrestore(&gatorfs_lock, flags);
81 return 0;
82}
83
Jon Medhurst15ce78d2014-04-10 09:02:02 +010084static int gatorfs_u64_from_user(u64 *val, char const __user *buf, size_t count)
Jon Medhurstaaf37a32013-06-11 12:10:56 +010085{
86 char tmpbuf[TMPBUFSIZE];
87 unsigned long flags;
88
89 if (!count)
90 return 0;
91
92 if (count > TMPBUFSIZE - 1)
93 return -EINVAL;
94
95 memset(tmpbuf, 0x0, TMPBUFSIZE);
96
97 if (copy_from_user(tmpbuf, buf, count))
98 return -EFAULT;
99
100 spin_lock_irqsave(&gatorfs_lock, flags);
101 *val = simple_strtoull(tmpbuf, NULL, 0);
102 spin_unlock_irqrestore(&gatorfs_lock, flags);
103 return 0;
104}
105
106static ssize_t ulong_read_file(struct file *file, char __user *buf, size_t count, loff_t *offset)
107{
108 unsigned long *val = file->private_data;
Jon Medhurst96b56152014-10-30 18:01:15 +0000109
Jon Medhurstaaf37a32013-06-11 12:10:56 +0100110 return gatorfs_ulong_to_user(*val, buf, count, offset);
111}
112
113static ssize_t u64_read_file(struct file *file, char __user *buf, size_t count, loff_t *offset)
114{
115 u64 *val = file->private_data;
Jon Medhurst96b56152014-10-30 18:01:15 +0000116
Jon Medhurstaaf37a32013-06-11 12:10:56 +0100117 return gatorfs_u64_to_user(*val, buf, count, offset);
118}
119
120static ssize_t ulong_write_file(struct file *file, char const __user *buf, size_t count, loff_t *offset)
121{
122 unsigned long *value = file->private_data;
123 int retval;
124
125 if (*offset)
126 return -EINVAL;
127
128 retval = gatorfs_ulong_from_user(value, buf, count);
129
130 if (retval)
131 return retval;
132 return count;
133}
134
135static ssize_t u64_write_file(struct file *file, char const __user *buf, size_t count, loff_t *offset)
136{
137 u64 *value = file->private_data;
138 int retval;
139
140 if (*offset)
141 return -EINVAL;
142
143 retval = gatorfs_u64_from_user(value, buf, count);
144
145 if (retval)
146 return retval;
147 return count;
148}
149
150static int default_open(struct inode *inode, struct file *filp)
151{
152 if (inode->i_private)
153 filp->private_data = inode->i_private;
154 return 0;
155}
156
157static const struct file_operations ulong_fops = {
158 .read = ulong_read_file,
159 .write = ulong_write_file,
160 .open = default_open,
161};
162
163static const struct file_operations u64_fops = {
164 .read = u64_read_file,
165 .write = u64_write_file,
166 .open = default_open,
167};
168
169static const struct file_operations ulong_ro_fops = {
170 .read = ulong_read_file,
171 .open = default_open,
172};
173
174static const struct file_operations u64_ro_fops = {
175 .read = u64_read_file,
176 .open = default_open,
177};
178
179static struct dentry *__gatorfs_create_file(struct super_block *sb,
180 struct dentry *root,
181 char const *name,
182 const struct file_operations *fops,
183 int perm)
184{
185 struct dentry *dentry;
186 struct inode *inode;
187
188 dentry = d_alloc_name(root, name);
189 if (!dentry)
190 return NULL;
191 inode = gatorfs_get_inode(sb, S_IFREG | perm);
192 if (!inode) {
193 dput(dentry);
194 return NULL;
195 }
196 inode->i_fop = fops;
197 d_add(dentry, inode);
198 return dentry;
199}
200
201int gatorfs_create_ulong(struct super_block *sb, struct dentry *root,
202 char const *name, unsigned long *val)
203{
204 struct dentry *d = __gatorfs_create_file(sb, root, name,
205 &ulong_fops, 0644);
206 if (!d)
207 return -EFAULT;
208
209 d->d_inode->i_private = val;
210 return 0;
211}
212
Jon Medhurst15ce78d2014-04-10 09:02:02 +0100213static int gatorfs_create_u64(struct super_block *sb, struct dentry *root,
214 char const *name, u64 *val)
Jon Medhurstaaf37a32013-06-11 12:10:56 +0100215{
216 struct dentry *d = __gatorfs_create_file(sb, root, name,
217 &u64_fops, 0644);
218 if (!d)
219 return -EFAULT;
220
221 d->d_inode->i_private = val;
222 return 0;
223}
224
225int gatorfs_create_ro_ulong(struct super_block *sb, struct dentry *root,
226 char const *name, unsigned long *val)
227{
228 struct dentry *d = __gatorfs_create_file(sb, root, name,
229 &ulong_ro_fops, 0444);
230 if (!d)
231 return -EFAULT;
232
233 d->d_inode->i_private = val;
234 return 0;
235}
236
Jon Medhurst15ce78d2014-04-10 09:02:02 +0100237static int gatorfs_create_ro_u64(struct super_block *sb, struct dentry *root,
Jon Medhurst96b56152014-10-30 18:01:15 +0000238 char const *name, u64 *val)
Jon Medhurstaaf37a32013-06-11 12:10:56 +0100239{
240 struct dentry *d =
241 __gatorfs_create_file(sb, root, name, &u64_ro_fops, 0444);
242 if (!d)
243 return -EFAULT;
244
245 d->d_inode->i_private = val;
246 return 0;
247}
248
249static ssize_t atomic_read_file(struct file *file, char __user *buf, size_t count, loff_t *offset)
250{
251 atomic_t *val = file->private_data;
Jon Medhurst96b56152014-10-30 18:01:15 +0000252
Jon Medhurstaaf37a32013-06-11 12:10:56 +0100253 return gatorfs_ulong_to_user(atomic_read(val), buf, count, offset);
254}
255
256static const struct file_operations atomic_ro_fops = {
257 .read = atomic_read_file,
258 .open = default_open,
259};
260
Jon Medhurst15ce78d2014-04-10 09:02:02 +0100261static int gatorfs_create_file(struct super_block *sb, struct dentry *root,
262 char const *name, const struct file_operations *fops)
Jon Medhurstaaf37a32013-06-11 12:10:56 +0100263{
264 if (!__gatorfs_create_file(sb, root, name, fops, 0644))
265 return -EFAULT;
266 return 0;
267}
268
Jon Medhurst15ce78d2014-04-10 09:02:02 +0100269static int gatorfs_create_file_perm(struct super_block *sb, struct dentry *root,
270 char const *name,
271 const struct file_operations *fops, int perm)
Jon Medhurstaaf37a32013-06-11 12:10:56 +0100272{
273 if (!__gatorfs_create_file(sb, root, name, fops, perm))
274 return -EFAULT;
275 return 0;
276}
277
278struct dentry *gatorfs_mkdir(struct super_block *sb,
279 struct dentry *root, char const *name)
280{
281 struct dentry *dentry;
282 struct inode *inode;
283
284 dentry = d_alloc_name(root, name);
285 if (!dentry)
286 return NULL;
287 inode = gatorfs_get_inode(sb, S_IFDIR | 0755);
288 if (!inode) {
289 dput(dentry);
290 return NULL;
291 }
292 inode->i_op = &simple_dir_inode_operations;
293 inode->i_fop = &simple_dir_operations;
294 d_add(dentry, inode);
295 return dentry;
296}
297
298static int gatorfs_fill_super(struct super_block *sb, void *data, int silent)
299{
300 struct inode *root_inode;
301 struct dentry *root_dentry;
302
303 sb->s_blocksize = PAGE_CACHE_SIZE;
304 sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
305 sb->s_magic = gatorfs_MAGIC;
306 sb->s_op = &s_ops;
307 sb->s_time_gran = 1;
308
309 root_inode = gatorfs_get_inode(sb, S_IFDIR | 0755);
310 if (!root_inode)
311 return -ENOMEM;
312 root_inode->i_op = &simple_dir_inode_operations;
313 root_inode->i_fop = &simple_dir_operations;
314
315#if LINUX_VERSION_CODE < KERNEL_VERSION(3, 4, 0)
316 root_dentry = d_alloc_root(root_inode);
317#else
318 root_dentry = d_make_root(root_inode);
319#endif
320
321 if (!root_dentry) {
322#if LINUX_VERSION_CODE < KERNEL_VERSION(3, 4, 0)
323 iput(root_inode);
324#endif
325 return -ENOMEM;
326 }
327
328 sb->s_root = root_dentry;
329
330 gator_op_create_files(sb, root_dentry);
331
332 return 0;
333}
334
335#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 39)
336static int gatorfs_get_sb(struct file_system_type *fs_type,
337 int flags, const char *dev_name, void *data,
338 struct vfsmount *mnt)
339{
340 return get_sb_single(fs_type, flags, data, gatorfs_fill_super, mnt);
341}
342#else
343static struct dentry *gatorfs_mount(struct file_system_type *fs_type,
344 int flags, const char *dev_name, void *data)
345{
346 return mount_nodev(fs_type, flags, data, gatorfs_fill_super);
347}
348#endif
349
350static struct file_system_type gatorfs_type = {
351 .owner = THIS_MODULE,
352 .name = "gatorfs",
353#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 39)
354 .get_sb = gatorfs_get_sb,
355#else
356 .mount = gatorfs_mount,
357#endif
358
359 .kill_sb = kill_litter_super,
360};
361
Jon Medhurst15ce78d2014-04-10 09:02:02 +0100362static int __init gatorfs_register(void)
Jon Medhurstaaf37a32013-06-11 12:10:56 +0100363{
364 return register_filesystem(&gatorfs_type);
365}
366
Jon Medhurst15ce78d2014-04-10 09:02:02 +0100367static void gatorfs_unregister(void)
Jon Medhurstaaf37a32013-06-11 12:10:56 +0100368{
369 unregister_filesystem(&gatorfs_type);
370}