Jon Medhurst | aaf37a3 | 2013-06-11 12:10:56 +0100 | [diff] [blame] | 1 | /** |
| 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 Medhurst | 96b5615 | 2014-10-30 18:01:15 +0000 | [diff] [blame^] | 17 | #include <linux/uaccess.h> |
Jon Medhurst | aaf37a3 | 2013-06-11 12:10:56 +0100 | [diff] [blame] | 18 | |
| 19 | #define gatorfs_MAGIC 0x24051020 |
| 20 | #define TMPBUFSIZE 50 |
| 21 | DEFINE_SPINLOCK(gatorfs_lock); |
| 22 | |
| 23 | static 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 | |
| 37 | static const struct super_operations s_ops = { |
| 38 | .statfs = simple_statfs, |
| 39 | .drop_inode = generic_delete_inode, |
| 40 | }; |
| 41 | |
Jon Medhurst | 15ce78d | 2014-04-10 09:02:02 +0100 | [diff] [blame] | 42 | static ssize_t gatorfs_ulong_to_user(unsigned long val, char __user *buf, size_t count, loff_t *offset) |
Jon Medhurst | aaf37a3 | 2013-06-11 12:10:56 +0100 | [diff] [blame] | 43 | { |
| 44 | char tmpbuf[TMPBUFSIZE]; |
| 45 | size_t maxlen = snprintf(tmpbuf, TMPBUFSIZE, "%lu\n", val); |
Jon Medhurst | 96b5615 | 2014-10-30 18:01:15 +0000 | [diff] [blame^] | 46 | |
Jon Medhurst | aaf37a3 | 2013-06-11 12:10:56 +0100 | [diff] [blame] | 47 | if (maxlen > TMPBUFSIZE) |
| 48 | maxlen = TMPBUFSIZE; |
| 49 | return simple_read_from_buffer(buf, count, offset, tmpbuf, maxlen); |
| 50 | } |
| 51 | |
Jon Medhurst | 15ce78d | 2014-04-10 09:02:02 +0100 | [diff] [blame] | 52 | static ssize_t gatorfs_u64_to_user(u64 val, char __user *buf, size_t count, loff_t *offset) |
Jon Medhurst | aaf37a3 | 2013-06-11 12:10:56 +0100 | [diff] [blame] | 53 | { |
| 54 | char tmpbuf[TMPBUFSIZE]; |
| 55 | size_t maxlen = snprintf(tmpbuf, TMPBUFSIZE, "%llu\n", val); |
Jon Medhurst | 96b5615 | 2014-10-30 18:01:15 +0000 | [diff] [blame^] | 56 | |
Jon Medhurst | aaf37a3 | 2013-06-11 12:10:56 +0100 | [diff] [blame] | 57 | if (maxlen > TMPBUFSIZE) |
| 58 | maxlen = TMPBUFSIZE; |
| 59 | return simple_read_from_buffer(buf, count, offset, tmpbuf, maxlen); |
| 60 | } |
| 61 | |
Jon Medhurst | 15ce78d | 2014-04-10 09:02:02 +0100 | [diff] [blame] | 62 | static int gatorfs_ulong_from_user(unsigned long *val, char const __user *buf, size_t count) |
Jon Medhurst | aaf37a3 | 2013-06-11 12:10:56 +0100 | [diff] [blame] | 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(&gatorfs_lock, flags); |
| 79 | *val = simple_strtoul(tmpbuf, NULL, 0); |
| 80 | spin_unlock_irqrestore(&gatorfs_lock, flags); |
| 81 | return 0; |
| 82 | } |
| 83 | |
Jon Medhurst | 15ce78d | 2014-04-10 09:02:02 +0100 | [diff] [blame] | 84 | static int gatorfs_u64_from_user(u64 *val, char const __user *buf, size_t count) |
Jon Medhurst | aaf37a3 | 2013-06-11 12:10:56 +0100 | [diff] [blame] | 85 | { |
| 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 | |
| 106 | static 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 Medhurst | 96b5615 | 2014-10-30 18:01:15 +0000 | [diff] [blame^] | 109 | |
Jon Medhurst | aaf37a3 | 2013-06-11 12:10:56 +0100 | [diff] [blame] | 110 | return gatorfs_ulong_to_user(*val, buf, count, offset); |
| 111 | } |
| 112 | |
| 113 | static 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 Medhurst | 96b5615 | 2014-10-30 18:01:15 +0000 | [diff] [blame^] | 116 | |
Jon Medhurst | aaf37a3 | 2013-06-11 12:10:56 +0100 | [diff] [blame] | 117 | return gatorfs_u64_to_user(*val, buf, count, offset); |
| 118 | } |
| 119 | |
| 120 | static 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 | |
| 135 | static 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 | |
| 150 | static 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 | |
| 157 | static const struct file_operations ulong_fops = { |
| 158 | .read = ulong_read_file, |
| 159 | .write = ulong_write_file, |
| 160 | .open = default_open, |
| 161 | }; |
| 162 | |
| 163 | static const struct file_operations u64_fops = { |
| 164 | .read = u64_read_file, |
| 165 | .write = u64_write_file, |
| 166 | .open = default_open, |
| 167 | }; |
| 168 | |
| 169 | static const struct file_operations ulong_ro_fops = { |
| 170 | .read = ulong_read_file, |
| 171 | .open = default_open, |
| 172 | }; |
| 173 | |
| 174 | static const struct file_operations u64_ro_fops = { |
| 175 | .read = u64_read_file, |
| 176 | .open = default_open, |
| 177 | }; |
| 178 | |
| 179 | static 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 | |
| 201 | int 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 Medhurst | 15ce78d | 2014-04-10 09:02:02 +0100 | [diff] [blame] | 213 | static int gatorfs_create_u64(struct super_block *sb, struct dentry *root, |
| 214 | char const *name, u64 *val) |
Jon Medhurst | aaf37a3 | 2013-06-11 12:10:56 +0100 | [diff] [blame] | 215 | { |
| 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 | |
| 225 | int 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 Medhurst | 15ce78d | 2014-04-10 09:02:02 +0100 | [diff] [blame] | 237 | static int gatorfs_create_ro_u64(struct super_block *sb, struct dentry *root, |
Jon Medhurst | 96b5615 | 2014-10-30 18:01:15 +0000 | [diff] [blame^] | 238 | char const *name, u64 *val) |
Jon Medhurst | aaf37a3 | 2013-06-11 12:10:56 +0100 | [diff] [blame] | 239 | { |
| 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 | |
| 249 | static 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 Medhurst | 96b5615 | 2014-10-30 18:01:15 +0000 | [diff] [blame^] | 252 | |
Jon Medhurst | aaf37a3 | 2013-06-11 12:10:56 +0100 | [diff] [blame] | 253 | return gatorfs_ulong_to_user(atomic_read(val), buf, count, offset); |
| 254 | } |
| 255 | |
| 256 | static const struct file_operations atomic_ro_fops = { |
| 257 | .read = atomic_read_file, |
| 258 | .open = default_open, |
| 259 | }; |
| 260 | |
Jon Medhurst | 15ce78d | 2014-04-10 09:02:02 +0100 | [diff] [blame] | 261 | static int gatorfs_create_file(struct super_block *sb, struct dentry *root, |
| 262 | char const *name, const struct file_operations *fops) |
Jon Medhurst | aaf37a3 | 2013-06-11 12:10:56 +0100 | [diff] [blame] | 263 | { |
| 264 | if (!__gatorfs_create_file(sb, root, name, fops, 0644)) |
| 265 | return -EFAULT; |
| 266 | return 0; |
| 267 | } |
| 268 | |
Jon Medhurst | 15ce78d | 2014-04-10 09:02:02 +0100 | [diff] [blame] | 269 | static 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 Medhurst | aaf37a3 | 2013-06-11 12:10:56 +0100 | [diff] [blame] | 272 | { |
| 273 | if (!__gatorfs_create_file(sb, root, name, fops, perm)) |
| 274 | return -EFAULT; |
| 275 | return 0; |
| 276 | } |
| 277 | |
| 278 | struct 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 | |
| 298 | static 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) |
| 336 | static 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 |
| 343 | static 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 | |
| 350 | static 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 Medhurst | 15ce78d | 2014-04-10 09:02:02 +0100 | [diff] [blame] | 362 | static int __init gatorfs_register(void) |
Jon Medhurst | aaf37a3 | 2013-06-11 12:10:56 +0100 | [diff] [blame] | 363 | { |
| 364 | return register_filesystem(&gatorfs_type); |
| 365 | } |
| 366 | |
Jon Medhurst | 15ce78d | 2014-04-10 09:02:02 +0100 | [diff] [blame] | 367 | static void gatorfs_unregister(void) |
Jon Medhurst | aaf37a3 | 2013-06-11 12:10:56 +0100 | [diff] [blame] | 368 | { |
| 369 | unregister_filesystem(&gatorfs_type); |
| 370 | } |