4 * @remark Copyright 2002 OProfile authors
5 * @remark Read the file COPYING
9 * A simple filesystem for configuration and
13 #include <linux/init.h>
14 #include <linux/module.h>
15 #include <linux/oprofile.h>
17 #include <linux/fs_context.h>
18 #include <linux/pagemap.h>
19 #include <linux/uaccess.h>
23 #define OPROFILEFS_MAGIC 0x6f70726f
25 DEFINE_RAW_SPINLOCK(oprofilefs_lock);
27 static struct inode *oprofilefs_get_inode(struct super_block *sb, int mode)
29 struct inode *inode = new_inode(sb);
32 inode->i_ino = get_next_ino();
34 inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
40 static const struct super_operations s_ops = {
41 .statfs = simple_statfs,
42 .drop_inode = generic_delete_inode,
46 ssize_t oprofilefs_str_to_user(char const *str, char __user *buf, size_t count, loff_t *offset)
48 return simple_read_from_buffer(buf, count, offset, str, strlen(str));
54 ssize_t oprofilefs_ulong_to_user(unsigned long val, char __user *buf, size_t count, loff_t *offset)
56 char tmpbuf[TMPBUFSIZE];
57 size_t maxlen = snprintf(tmpbuf, TMPBUFSIZE, "%lu\n", val);
58 if (maxlen > TMPBUFSIZE)
60 return simple_read_from_buffer(buf, count, offset, tmpbuf, maxlen);
65 * Note: If oprofilefs_ulong_from_user() returns 0, then *val remains
66 * unchanged and might be uninitialized. This follows write syscall
67 * implementation when count is zero: "If count is zero ... [and if]
68 * no errors are detected, 0 will be returned without causing any
69 * other effect." (man 2 write)
71 int oprofilefs_ulong_from_user(unsigned long *val, char const __user *buf, size_t count)
73 char tmpbuf[TMPBUFSIZE];
79 if (count > TMPBUFSIZE - 1)
82 memset(tmpbuf, 0x0, TMPBUFSIZE);
84 if (copy_from_user(tmpbuf, buf, count))
87 raw_spin_lock_irqsave(&oprofilefs_lock, flags);
88 *val = simple_strtoul(tmpbuf, NULL, 0);
89 raw_spin_unlock_irqrestore(&oprofilefs_lock, flags);
94 static ssize_t ulong_read_file(struct file *file, char __user *buf, size_t count, loff_t *offset)
96 unsigned long *val = file->private_data;
97 return oprofilefs_ulong_to_user(*val, buf, count, offset);
101 static ssize_t ulong_write_file(struct file *file, char const __user *buf, size_t count, loff_t *offset)
109 retval = oprofilefs_ulong_from_user(&value, buf, count);
113 retval = oprofile_set_ulong(file->private_data, value);
121 static const struct file_operations ulong_fops = {
122 .read = ulong_read_file,
123 .write = ulong_write_file,
125 .llseek = default_llseek,
129 static const struct file_operations ulong_ro_fops = {
130 .read = ulong_read_file,
132 .llseek = default_llseek,
136 static int __oprofilefs_create_file(struct dentry *root, char const *name,
137 const struct file_operations *fops, int perm, void *priv)
139 struct dentry *dentry;
145 inode_lock(d_inode(root));
146 dentry = d_alloc_name(root, name);
148 inode_unlock(d_inode(root));
151 inode = oprofilefs_get_inode(root->d_sb, S_IFREG | perm);
154 inode_unlock(d_inode(root));
158 inode->i_private = priv;
159 d_add(dentry, inode);
160 inode_unlock(d_inode(root));
165 int oprofilefs_create_ulong(struct dentry *root,
166 char const *name, unsigned long *val)
168 return __oprofilefs_create_file(root, name,
169 &ulong_fops, 0644, val);
173 int oprofilefs_create_ro_ulong(struct dentry *root,
174 char const *name, unsigned long *val)
176 return __oprofilefs_create_file(root, name,
177 &ulong_ro_fops, 0444, val);
181 static ssize_t atomic_read_file(struct file *file, char __user *buf, size_t count, loff_t *offset)
183 atomic_t *val = file->private_data;
184 return oprofilefs_ulong_to_user(atomic_read(val), buf, count, offset);
188 static const struct file_operations atomic_ro_fops = {
189 .read = atomic_read_file,
191 .llseek = default_llseek,
195 int oprofilefs_create_ro_atomic(struct dentry *root,
196 char const *name, atomic_t *val)
198 return __oprofilefs_create_file(root, name,
199 &atomic_ro_fops, 0444, val);
203 int oprofilefs_create_file(struct dentry *root,
204 char const *name, const struct file_operations *fops)
206 return __oprofilefs_create_file(root, name, fops, 0644, NULL);
210 int oprofilefs_create_file_perm(struct dentry *root,
211 char const *name, const struct file_operations *fops, int perm)
213 return __oprofilefs_create_file(root, name, fops, perm, NULL);
217 struct dentry *oprofilefs_mkdir(struct dentry *parent, char const *name)
219 struct dentry *dentry;
222 inode_lock(d_inode(parent));
223 dentry = d_alloc_name(parent, name);
225 inode_unlock(d_inode(parent));
228 inode = oprofilefs_get_inode(parent->d_sb, S_IFDIR | 0755);
231 inode_unlock(d_inode(parent));
234 inode->i_op = &simple_dir_inode_operations;
235 inode->i_fop = &simple_dir_operations;
236 d_add(dentry, inode);
237 inode_unlock(d_inode(parent));
242 static int oprofilefs_fill_super(struct super_block *sb, struct fs_context *fc)
244 struct inode *root_inode;
246 sb->s_blocksize = PAGE_SIZE;
247 sb->s_blocksize_bits = PAGE_SHIFT;
248 sb->s_magic = OPROFILEFS_MAGIC;
252 root_inode = oprofilefs_get_inode(sb, S_IFDIR | 0755);
255 root_inode->i_op = &simple_dir_inode_operations;
256 root_inode->i_fop = &simple_dir_operations;
257 sb->s_root = d_make_root(root_inode);
261 oprofile_create_files(sb->s_root);
263 // FIXME: verify kill_litter_super removes our dentries
267 static int oprofilefs_get_tree(struct fs_context *fc)
269 return get_tree_single(fc, oprofilefs_fill_super);
272 static const struct fs_context_operations oprofilefs_context_ops = {
273 .get_tree = oprofilefs_get_tree,
276 static int oprofilefs_init_fs_context(struct fs_context *fc)
278 fc->ops = &oprofilefs_context_ops;
282 static struct file_system_type oprofilefs_type = {
283 .owner = THIS_MODULE,
284 .name = "oprofilefs",
285 .init_fs_context = oprofilefs_init_fs_context,
286 .kill_sb = kill_litter_super,
288 MODULE_ALIAS_FS("oprofilefs");
291 int __init oprofilefs_register(void)
293 return register_filesystem(&oprofilefs_type);
297 void __exit oprofilefs_unregister(void)
299 unregister_filesystem(&oprofilefs_type);