oprofilefs.c revision 56ff5efad96182f4d3cb3dc6b07396762c658f16
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 24DEFINE_SPINLOCK(oprofilefs_lock); 25 26static 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 38static struct super_operations s_ops = { 39 .statfs = simple_statfs, 40 .drop_inode = generic_delete_inode, 41}; 42 43 44ssize_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 52ssize_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 62int 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 85static 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 92static ssize_t ulong_write_file(struct file *file, char const __user *buf, size_t count, loff_t *offset) 93{ 94 unsigned long *value = file->private_data; 95 int retval; 96 97 if (*offset) 98 return -EINVAL; 99 100 retval = oprofilefs_ulong_from_user(value, buf, count); 101 102 if (retval) 103 return retval; 104 return count; 105} 106 107 108static int default_open(struct inode *inode, struct file *filp) 109{ 110 if (inode->i_private) 111 filp->private_data = inode->i_private; 112 return 0; 113} 114 115 116static const struct file_operations ulong_fops = { 117 .read = ulong_read_file, 118 .write = ulong_write_file, 119 .open = default_open, 120}; 121 122 123static const struct file_operations ulong_ro_fops = { 124 .read = ulong_read_file, 125 .open = default_open, 126}; 127 128 129static struct dentry *__oprofilefs_create_file(struct super_block *sb, 130 struct dentry *root, char const *name, const struct file_operations *fops, 131 int perm) 132{ 133 struct dentry *dentry; 134 struct inode *inode; 135 136 dentry = d_alloc_name(root, name); 137 if (!dentry) 138 return NULL; 139 inode = oprofilefs_get_inode(sb, S_IFREG | perm); 140 if (!inode) { 141 dput(dentry); 142 return NULL; 143 } 144 inode->i_fop = fops; 145 d_add(dentry, inode); 146 return dentry; 147} 148 149 150int oprofilefs_create_ulong(struct super_block *sb, struct dentry *root, 151 char const *name, unsigned long *val) 152{ 153 struct dentry *d = __oprofilefs_create_file(sb, root, name, 154 &ulong_fops, 0644); 155 if (!d) 156 return -EFAULT; 157 158 d->d_inode->i_private = val; 159 return 0; 160} 161 162 163int oprofilefs_create_ro_ulong(struct super_block *sb, struct dentry *root, 164 char const *name, unsigned long *val) 165{ 166 struct dentry *d = __oprofilefs_create_file(sb, root, name, 167 &ulong_ro_fops, 0444); 168 if (!d) 169 return -EFAULT; 170 171 d->d_inode->i_private = val; 172 return 0; 173} 174 175 176static ssize_t atomic_read_file(struct file *file, char __user *buf, size_t count, loff_t *offset) 177{ 178 atomic_t *val = file->private_data; 179 return oprofilefs_ulong_to_user(atomic_read(val), buf, count, offset); 180} 181 182 183static const struct file_operations atomic_ro_fops = { 184 .read = atomic_read_file, 185 .open = default_open, 186}; 187 188 189int oprofilefs_create_ro_atomic(struct super_block *sb, struct dentry *root, 190 char const *name, atomic_t *val) 191{ 192 struct dentry *d = __oprofilefs_create_file(sb, root, name, 193 &atomic_ro_fops, 0444); 194 if (!d) 195 return -EFAULT; 196 197 d->d_inode->i_private = val; 198 return 0; 199} 200 201 202int oprofilefs_create_file(struct super_block *sb, struct dentry *root, 203 char const *name, const struct file_operations *fops) 204{ 205 if (!__oprofilefs_create_file(sb, root, name, fops, 0644)) 206 return -EFAULT; 207 return 0; 208} 209 210 211int oprofilefs_create_file_perm(struct super_block *sb, struct dentry *root, 212 char const *name, const struct file_operations *fops, int perm) 213{ 214 if (!__oprofilefs_create_file(sb, root, name, fops, perm)) 215 return -EFAULT; 216 return 0; 217} 218 219 220struct dentry *oprofilefs_mkdir(struct super_block *sb, 221 struct dentry *root, char const *name) 222{ 223 struct dentry *dentry; 224 struct inode *inode; 225 226 dentry = d_alloc_name(root, name); 227 if (!dentry) 228 return NULL; 229 inode = oprofilefs_get_inode(sb, S_IFDIR | 0755); 230 if (!inode) { 231 dput(dentry); 232 return NULL; 233 } 234 inode->i_op = &simple_dir_inode_operations; 235 inode->i_fop = &simple_dir_operations; 236 d_add(dentry, inode); 237 return dentry; 238} 239 240 241static int oprofilefs_fill_super(struct super_block *sb, void *data, int silent) 242{ 243 struct inode *root_inode; 244 struct dentry *root_dentry; 245 246 sb->s_blocksize = PAGE_CACHE_SIZE; 247 sb->s_blocksize_bits = PAGE_CACHE_SHIFT; 248 sb->s_magic = OPROFILEFS_MAGIC; 249 sb->s_op = &s_ops; 250 sb->s_time_gran = 1; 251 252 root_inode = oprofilefs_get_inode(sb, S_IFDIR | 0755); 253 if (!root_inode) 254 return -ENOMEM; 255 root_inode->i_op = &simple_dir_inode_operations; 256 root_inode->i_fop = &simple_dir_operations; 257 root_dentry = d_alloc_root(root_inode); 258 if (!root_dentry) { 259 iput(root_inode); 260 return -ENOMEM; 261 } 262 263 sb->s_root = root_dentry; 264 265 oprofile_create_files(sb, root_dentry); 266 267 // FIXME: verify kill_litter_super removes our dentries 268 return 0; 269} 270 271 272static int oprofilefs_get_sb(struct file_system_type *fs_type, 273 int flags, const char *dev_name, void *data, struct vfsmount *mnt) 274{ 275 return get_sb_single(fs_type, flags, data, oprofilefs_fill_super, mnt); 276} 277 278 279static struct file_system_type oprofilefs_type = { 280 .owner = THIS_MODULE, 281 .name = "oprofilefs", 282 .get_sb = oprofilefs_get_sb, 283 .kill_sb = kill_litter_super, 284}; 285 286 287int __init oprofilefs_register(void) 288{ 289 return register_filesystem(&oprofilefs_type); 290} 291 292 293void __exit oprofilefs_unregister(void) 294{ 295 unregister_filesystem(&oprofilefs_type); 296} 297