| 1 | /* |
| 2 | * inode.c - part of debugfs, a tiny little debug file system |
| 3 | * |
| 4 | * Copyright (C) 2004 Greg Kroah-Hartman <greg@kroah.com> |
| 5 | * Copyright (C) 2004 IBM Inc. |
| 6 | * |
| 7 | * This program is free software; you can redistribute it and/or |
| 8 | * modify it under the terms of the GNU General Public License version |
| 9 | * 2 as published by the Free Software Foundation. |
| 10 | * |
| 11 | * debugfs is for people to use instead of /proc or /sys. |
| 12 | * See Documentation/DocBook/kernel-api for more details. |
| 13 | * |
| 14 | */ |
| 15 | |
| 16 | #include <linux/module.h> |
| 17 | #include <linux/fs.h> |
| 18 | #include <linux/mount.h> |
| 19 | #include <linux/pagemap.h> |
| 20 | #include <linux/init.h> |
| 21 | #include <linux/kobject.h> |
| 22 | #include <linux/namei.h> |
| 23 | #include <linux/debugfs.h> |
| 24 | #include <linux/fsnotify.h> |
| 25 | #include <linux/string.h> |
| 26 | #include <linux/seq_file.h> |
| 27 | #include <linux/parser.h> |
| 28 | #include <linux/magic.h> |
| 29 | #include <linux/slab.h> |
| 30 | |
| 31 | #define DEBUGFS_DEFAULT_MODE 0700 |
| 32 | |
| 33 | static struct vfsmount *debugfs_mount; |
| 34 | static int debugfs_mount_count; |
| 35 | static bool debugfs_registered; |
| 36 | |
| 37 | static struct inode *debugfs_get_inode(struct super_block *sb) |
| 38 | { |
| 39 | struct inode *inode = new_inode(sb); |
| 40 | if (inode) { |
| 41 | inode->i_ino = get_next_ino(); |
| 42 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; |
| 43 | } |
| 44 | return inode; |
| 45 | } |
| 46 | |
| 47 | struct debugfs_mount_opts { |
| 48 | kuid_t uid; |
| 49 | kgid_t gid; |
| 50 | umode_t mode; |
| 51 | }; |
| 52 | |
| 53 | enum { |
| 54 | Opt_uid, |
| 55 | Opt_gid, |
| 56 | Opt_mode, |
| 57 | Opt_err |
| 58 | }; |
| 59 | |
| 60 | static const match_table_t tokens = { |
| 61 | {Opt_uid, "uid=%u"}, |
| 62 | {Opt_gid, "gid=%u"}, |
| 63 | {Opt_mode, "mode=%o"}, |
| 64 | {Opt_err, NULL} |
| 65 | }; |
| 66 | |
| 67 | struct debugfs_fs_info { |
| 68 | struct debugfs_mount_opts mount_opts; |
| 69 | }; |
| 70 | |
| 71 | static int debugfs_parse_options(char *data, struct debugfs_mount_opts *opts) |
| 72 | { |
| 73 | substring_t args[MAX_OPT_ARGS]; |
| 74 | int option; |
| 75 | int token; |
| 76 | kuid_t uid; |
| 77 | kgid_t gid; |
| 78 | char *p; |
| 79 | |
| 80 | opts->mode = DEBUGFS_DEFAULT_MODE; |
| 81 | |
| 82 | while ((p = strsep(&data, ",")) != NULL) { |
| 83 | if (!*p) |
| 84 | continue; |
| 85 | |
| 86 | token = match_token(p, tokens, args); |
| 87 | switch (token) { |
| 88 | case Opt_uid: |
| 89 | if (match_int(&args[0], &option)) |
| 90 | return -EINVAL; |
| 91 | uid = make_kuid(current_user_ns(), option); |
| 92 | if (!uid_valid(uid)) |
| 93 | return -EINVAL; |
| 94 | opts->uid = uid; |
| 95 | break; |
| 96 | case Opt_gid: |
| 97 | if (match_int(&args[0], &option)) |
| 98 | return -EINVAL; |
| 99 | gid = make_kgid(current_user_ns(), option); |
| 100 | if (!gid_valid(gid)) |
| 101 | return -EINVAL; |
| 102 | opts->gid = gid; |
| 103 | break; |
| 104 | case Opt_mode: |
| 105 | if (match_octal(&args[0], &option)) |
| 106 | return -EINVAL; |
| 107 | opts->mode = option & S_IALLUGO; |
| 108 | break; |
| 109 | /* |
| 110 | * We might like to report bad mount options here; |
| 111 | * but traditionally debugfs has ignored all mount options |
| 112 | */ |
| 113 | } |
| 114 | } |
| 115 | |
| 116 | return 0; |
| 117 | } |
| 118 | |
| 119 | static int debugfs_apply_options(struct super_block *sb) |
| 120 | { |
| 121 | struct debugfs_fs_info *fsi = sb->s_fs_info; |
| 122 | struct inode *inode = d_inode(sb->s_root); |
| 123 | struct debugfs_mount_opts *opts = &fsi->mount_opts; |
| 124 | |
| 125 | inode->i_mode &= ~S_IALLUGO; |
| 126 | inode->i_mode |= opts->mode; |
| 127 | |
| 128 | inode->i_uid = opts->uid; |
| 129 | inode->i_gid = opts->gid; |
| 130 | |
| 131 | return 0; |
| 132 | } |
| 133 | |
| 134 | static int debugfs_remount(struct super_block *sb, int *flags, char *data) |
| 135 | { |
| 136 | int err; |
| 137 | struct debugfs_fs_info *fsi = sb->s_fs_info; |
| 138 | |
| 139 | sync_filesystem(sb); |
| 140 | err = debugfs_parse_options(data, &fsi->mount_opts); |
| 141 | if (err) |
| 142 | goto fail; |
| 143 | |
| 144 | debugfs_apply_options(sb); |
| 145 | |
| 146 | fail: |
| 147 | return err; |
| 148 | } |
| 149 | |
| 150 | static int debugfs_show_options(struct seq_file *m, struct dentry *root) |
| 151 | { |
| 152 | struct debugfs_fs_info *fsi = root->d_sb->s_fs_info; |
| 153 | struct debugfs_mount_opts *opts = &fsi->mount_opts; |
| 154 | |
| 155 | if (!uid_eq(opts->uid, GLOBAL_ROOT_UID)) |
| 156 | seq_printf(m, ",uid=%u", |
| 157 | from_kuid_munged(&init_user_ns, opts->uid)); |
| 158 | if (!gid_eq(opts->gid, GLOBAL_ROOT_GID)) |
| 159 | seq_printf(m, ",gid=%u", |
| 160 | from_kgid_munged(&init_user_ns, opts->gid)); |
| 161 | if (opts->mode != DEBUGFS_DEFAULT_MODE) |
| 162 | seq_printf(m, ",mode=%o", opts->mode); |
| 163 | |
| 164 | return 0; |
| 165 | } |
| 166 | |
| 167 | static void debugfs_evict_inode(struct inode *inode) |
| 168 | { |
| 169 | truncate_inode_pages_final(&inode->i_data); |
| 170 | clear_inode(inode); |
| 171 | if (S_ISLNK(inode->i_mode)) |
| 172 | kfree(inode->i_link); |
| 173 | } |
| 174 | |
| 175 | static const struct super_operations debugfs_super_operations = { |
| 176 | .statfs = simple_statfs, |
| 177 | .remount_fs = debugfs_remount, |
| 178 | .show_options = debugfs_show_options, |
| 179 | .evict_inode = debugfs_evict_inode, |
| 180 | }; |
| 181 | |
| 182 | static struct vfsmount *debugfs_automount(struct path *path) |
| 183 | { |
| 184 | struct vfsmount *(*f)(void *); |
| 185 | f = (struct vfsmount *(*)(void *))path->dentry->d_fsdata; |
| 186 | return f(d_inode(path->dentry)->i_private); |
| 187 | } |
| 188 | |
| 189 | static const struct dentry_operations debugfs_dops = { |
| 190 | .d_delete = always_delete_dentry, |
| 191 | .d_automount = debugfs_automount, |
| 192 | }; |
| 193 | |
| 194 | static int debug_fill_super(struct super_block *sb, void *data, int silent) |
| 195 | { |
| 196 | static struct tree_descr debug_files[] = {{""}}; |
| 197 | struct debugfs_fs_info *fsi; |
| 198 | int err; |
| 199 | |
| 200 | save_mount_options(sb, data); |
| 201 | |
| 202 | fsi = kzalloc(sizeof(struct debugfs_fs_info), GFP_KERNEL); |
| 203 | sb->s_fs_info = fsi; |
| 204 | if (!fsi) { |
| 205 | err = -ENOMEM; |
| 206 | goto fail; |
| 207 | } |
| 208 | |
| 209 | err = debugfs_parse_options(data, &fsi->mount_opts); |
| 210 | if (err) |
| 211 | goto fail; |
| 212 | |
| 213 | err = simple_fill_super(sb, DEBUGFS_MAGIC, debug_files); |
| 214 | if (err) |
| 215 | goto fail; |
| 216 | |
| 217 | sb->s_op = &debugfs_super_operations; |
| 218 | sb->s_d_op = &debugfs_dops; |
| 219 | |
| 220 | debugfs_apply_options(sb); |
| 221 | |
| 222 | return 0; |
| 223 | |
| 224 | fail: |
| 225 | kfree(fsi); |
| 226 | sb->s_fs_info = NULL; |
| 227 | return err; |
| 228 | } |
| 229 | |
| 230 | static struct dentry *debug_mount(struct file_system_type *fs_type, |
| 231 | int flags, const char *dev_name, |
| 232 | void *data) |
| 233 | { |
| 234 | return mount_single(fs_type, flags, data, debug_fill_super); |
| 235 | } |
| 236 | |
| 237 | static struct file_system_type debug_fs_type = { |
| 238 | .owner = THIS_MODULE, |
| 239 | .name = "debugfs", |
| 240 | .mount = debug_mount, |
| 241 | .kill_sb = kill_litter_super, |
| 242 | }; |
| 243 | MODULE_ALIAS_FS("debugfs"); |
| 244 | |
| 245 | static struct dentry *start_creating(const char *name, struct dentry *parent) |
| 246 | { |
| 247 | struct dentry *dentry; |
| 248 | int error; |
| 249 | |
| 250 | pr_debug("debugfs: creating file '%s'\n",name); |
| 251 | |
| 252 | if (IS_ERR(parent)) |
| 253 | return parent; |
| 254 | |
| 255 | error = simple_pin_fs(&debug_fs_type, &debugfs_mount, |
| 256 | &debugfs_mount_count); |
| 257 | if (error) |
| 258 | return ERR_PTR(error); |
| 259 | |
| 260 | /* If the parent is not specified, we create it in the root. |
| 261 | * We need the root dentry to do this, which is in the super |
| 262 | * block. A pointer to that is in the struct vfsmount that we |
| 263 | * have around. |
| 264 | */ |
| 265 | if (!parent) |
| 266 | parent = debugfs_mount->mnt_root; |
| 267 | |
| 268 | inode_lock(d_inode(parent)); |
| 269 | dentry = lookup_one_len(name, parent, strlen(name)); |
| 270 | if (!IS_ERR(dentry) && d_really_is_positive(dentry)) { |
| 271 | dput(dentry); |
| 272 | dentry = ERR_PTR(-EEXIST); |
| 273 | } |
| 274 | |
| 275 | if (IS_ERR(dentry)) { |
| 276 | inode_unlock(d_inode(parent)); |
| 277 | simple_release_fs(&debugfs_mount, &debugfs_mount_count); |
| 278 | } |
| 279 | |
| 280 | return dentry; |
| 281 | } |
| 282 | |
| 283 | static struct dentry *failed_creating(struct dentry *dentry) |
| 284 | { |
| 285 | inode_unlock(d_inode(dentry->d_parent)); |
| 286 | dput(dentry); |
| 287 | simple_release_fs(&debugfs_mount, &debugfs_mount_count); |
| 288 | return NULL; |
| 289 | } |
| 290 | |
| 291 | static struct dentry *end_creating(struct dentry *dentry) |
| 292 | { |
| 293 | inode_unlock(d_inode(dentry->d_parent)); |
| 294 | return dentry; |
| 295 | } |
| 296 | |
| 297 | /** |
| 298 | * debugfs_create_file - create a file in the debugfs filesystem |
| 299 | * @name: a pointer to a string containing the name of the file to create. |
| 300 | * @mode: the permission that the file should have. |
| 301 | * @parent: a pointer to the parent dentry for this file. This should be a |
| 302 | * directory dentry if set. If this parameter is NULL, then the |
| 303 | * file will be created in the root of the debugfs filesystem. |
| 304 | * @data: a pointer to something that the caller will want to get to later |
| 305 | * on. The inode.i_private pointer will point to this value on |
| 306 | * the open() call. |
| 307 | * @fops: a pointer to a struct file_operations that should be used for |
| 308 | * this file. |
| 309 | * |
| 310 | * This is the basic "create a file" function for debugfs. It allows for a |
| 311 | * wide range of flexibility in creating a file, or a directory (if you want |
| 312 | * to create a directory, the debugfs_create_dir() function is |
| 313 | * recommended to be used instead.) |
| 314 | * |
| 315 | * This function will return a pointer to a dentry if it succeeds. This |
| 316 | * pointer must be passed to the debugfs_remove() function when the file is |
| 317 | * to be removed (no automatic cleanup happens if your module is unloaded, |
| 318 | * you are responsible here.) If an error occurs, %NULL will be returned. |
| 319 | * |
| 320 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be |
| 321 | * returned. |
| 322 | */ |
| 323 | struct dentry *debugfs_create_file(const char *name, umode_t mode, |
| 324 | struct dentry *parent, void *data, |
| 325 | const struct file_operations *fops) |
| 326 | { |
| 327 | struct dentry *dentry; |
| 328 | struct inode *inode; |
| 329 | |
| 330 | if (!(mode & S_IFMT)) |
| 331 | mode |= S_IFREG; |
| 332 | BUG_ON(!S_ISREG(mode)); |
| 333 | dentry = start_creating(name, parent); |
| 334 | |
| 335 | if (IS_ERR(dentry)) |
| 336 | return NULL; |
| 337 | |
| 338 | inode = debugfs_get_inode(dentry->d_sb); |
| 339 | if (unlikely(!inode)) |
| 340 | return failed_creating(dentry); |
| 341 | |
| 342 | inode->i_mode = mode; |
| 343 | inode->i_fop = fops ? fops : &debugfs_file_operations; |
| 344 | inode->i_private = data; |
| 345 | d_instantiate(dentry, inode); |
| 346 | fsnotify_create(d_inode(dentry->d_parent), dentry); |
| 347 | return end_creating(dentry); |
| 348 | } |
| 349 | EXPORT_SYMBOL_GPL(debugfs_create_file); |
| 350 | |
| 351 | /** |
| 352 | * debugfs_create_file_size - create a file in the debugfs filesystem |
| 353 | * @name: a pointer to a string containing the name of the file to create. |
| 354 | * @mode: the permission that the file should have. |
| 355 | * @parent: a pointer to the parent dentry for this file. This should be a |
| 356 | * directory dentry if set. If this parameter is NULL, then the |
| 357 | * file will be created in the root of the debugfs filesystem. |
| 358 | * @data: a pointer to something that the caller will want to get to later |
| 359 | * on. The inode.i_private pointer will point to this value on |
| 360 | * the open() call. |
| 361 | * @fops: a pointer to a struct file_operations that should be used for |
| 362 | * this file. |
| 363 | * @file_size: initial file size |
| 364 | * |
| 365 | * This is the basic "create a file" function for debugfs. It allows for a |
| 366 | * wide range of flexibility in creating a file, or a directory (if you want |
| 367 | * to create a directory, the debugfs_create_dir() function is |
| 368 | * recommended to be used instead.) |
| 369 | * |
| 370 | * This function will return a pointer to a dentry if it succeeds. This |
| 371 | * pointer must be passed to the debugfs_remove() function when the file is |
| 372 | * to be removed (no automatic cleanup happens if your module is unloaded, |
| 373 | * you are responsible here.) If an error occurs, %NULL will be returned. |
| 374 | * |
| 375 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be |
| 376 | * returned. |
| 377 | */ |
| 378 | struct dentry *debugfs_create_file_size(const char *name, umode_t mode, |
| 379 | struct dentry *parent, void *data, |
| 380 | const struct file_operations *fops, |
| 381 | loff_t file_size) |
| 382 | { |
| 383 | struct dentry *de = debugfs_create_file(name, mode, parent, data, fops); |
| 384 | |
| 385 | if (de) |
| 386 | d_inode(de)->i_size = file_size; |
| 387 | return de; |
| 388 | } |
| 389 | EXPORT_SYMBOL_GPL(debugfs_create_file_size); |
| 390 | |
| 391 | /** |
| 392 | * debugfs_create_dir - create a directory in the debugfs filesystem |
| 393 | * @name: a pointer to a string containing the name of the directory to |
| 394 | * create. |
| 395 | * @parent: a pointer to the parent dentry for this file. This should be a |
| 396 | * directory dentry if set. If this parameter is NULL, then the |
| 397 | * directory will be created in the root of the debugfs filesystem. |
| 398 | * |
| 399 | * This function creates a directory in debugfs with the given name. |
| 400 | * |
| 401 | * This function will return a pointer to a dentry if it succeeds. This |
| 402 | * pointer must be passed to the debugfs_remove() function when the file is |
| 403 | * to be removed (no automatic cleanup happens if your module is unloaded, |
| 404 | * you are responsible here.) If an error occurs, %NULL will be returned. |
| 405 | * |
| 406 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be |
| 407 | * returned. |
| 408 | */ |
| 409 | struct dentry *debugfs_create_dir(const char *name, struct dentry *parent) |
| 410 | { |
| 411 | struct dentry *dentry = start_creating(name, parent); |
| 412 | struct inode *inode; |
| 413 | |
| 414 | if (IS_ERR(dentry)) |
| 415 | return NULL; |
| 416 | |
| 417 | inode = debugfs_get_inode(dentry->d_sb); |
| 418 | if (unlikely(!inode)) |
| 419 | return failed_creating(dentry); |
| 420 | |
| 421 | inode->i_mode = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO; |
| 422 | inode->i_op = &simple_dir_inode_operations; |
| 423 | inode->i_fop = &simple_dir_operations; |
| 424 | |
| 425 | /* directory inodes start off with i_nlink == 2 (for "." entry) */ |
| 426 | inc_nlink(inode); |
| 427 | d_instantiate(dentry, inode); |
| 428 | inc_nlink(d_inode(dentry->d_parent)); |
| 429 | fsnotify_mkdir(d_inode(dentry->d_parent), dentry); |
| 430 | return end_creating(dentry); |
| 431 | } |
| 432 | EXPORT_SYMBOL_GPL(debugfs_create_dir); |
| 433 | |
| 434 | /** |
| 435 | * debugfs_create_automount - create automount point in the debugfs filesystem |
| 436 | * @name: a pointer to a string containing the name of the file to create. |
| 437 | * @parent: a pointer to the parent dentry for this file. This should be a |
| 438 | * directory dentry if set. If this parameter is NULL, then the |
| 439 | * file will be created in the root of the debugfs filesystem. |
| 440 | * @f: function to be called when pathname resolution steps on that one. |
| 441 | * @data: opaque argument to pass to f(). |
| 442 | * |
| 443 | * @f should return what ->d_automount() would. |
| 444 | */ |
| 445 | struct dentry *debugfs_create_automount(const char *name, |
| 446 | struct dentry *parent, |
| 447 | struct vfsmount *(*f)(void *), |
| 448 | void *data) |
| 449 | { |
| 450 | struct dentry *dentry = start_creating(name, parent); |
| 451 | struct inode *inode; |
| 452 | |
| 453 | if (IS_ERR(dentry)) |
| 454 | return NULL; |
| 455 | |
| 456 | inode = debugfs_get_inode(dentry->d_sb); |
| 457 | if (unlikely(!inode)) |
| 458 | return failed_creating(dentry); |
| 459 | |
| 460 | make_empty_dir_inode(inode); |
| 461 | inode->i_flags |= S_AUTOMOUNT; |
| 462 | inode->i_private = data; |
| 463 | dentry->d_fsdata = (void *)f; |
| 464 | d_instantiate(dentry, inode); |
| 465 | return end_creating(dentry); |
| 466 | } |
| 467 | EXPORT_SYMBOL(debugfs_create_automount); |
| 468 | |
| 469 | /** |
| 470 | * debugfs_create_symlink- create a symbolic link in the debugfs filesystem |
| 471 | * @name: a pointer to a string containing the name of the symbolic link to |
| 472 | * create. |
| 473 | * @parent: a pointer to the parent dentry for this symbolic link. This |
| 474 | * should be a directory dentry if set. If this parameter is NULL, |
| 475 | * then the symbolic link will be created in the root of the debugfs |
| 476 | * filesystem. |
| 477 | * @target: a pointer to a string containing the path to the target of the |
| 478 | * symbolic link. |
| 479 | * |
| 480 | * This function creates a symbolic link with the given name in debugfs that |
| 481 | * links to the given target path. |
| 482 | * |
| 483 | * This function will return a pointer to a dentry if it succeeds. This |
| 484 | * pointer must be passed to the debugfs_remove() function when the symbolic |
| 485 | * link is to be removed (no automatic cleanup happens if your module is |
| 486 | * unloaded, you are responsible here.) If an error occurs, %NULL will be |
| 487 | * returned. |
| 488 | * |
| 489 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be |
| 490 | * returned. |
| 491 | */ |
| 492 | struct dentry *debugfs_create_symlink(const char *name, struct dentry *parent, |
| 493 | const char *target) |
| 494 | { |
| 495 | struct dentry *dentry; |
| 496 | struct inode *inode; |
| 497 | char *link = kstrdup(target, GFP_KERNEL); |
| 498 | if (!link) |
| 499 | return NULL; |
| 500 | |
| 501 | dentry = start_creating(name, parent); |
| 502 | if (IS_ERR(dentry)) { |
| 503 | kfree(link); |
| 504 | return NULL; |
| 505 | } |
| 506 | |
| 507 | inode = debugfs_get_inode(dentry->d_sb); |
| 508 | if (unlikely(!inode)) { |
| 509 | kfree(link); |
| 510 | return failed_creating(dentry); |
| 511 | } |
| 512 | inode->i_mode = S_IFLNK | S_IRWXUGO; |
| 513 | inode->i_op = &simple_symlink_inode_operations; |
| 514 | inode->i_link = link; |
| 515 | d_instantiate(dentry, inode); |
| 516 | return end_creating(dentry); |
| 517 | } |
| 518 | EXPORT_SYMBOL_GPL(debugfs_create_symlink); |
| 519 | |
| 520 | static int __debugfs_remove(struct dentry *dentry, struct dentry *parent) |
| 521 | { |
| 522 | int ret = 0; |
| 523 | |
| 524 | if (simple_positive(dentry)) { |
| 525 | dget(dentry); |
| 526 | if (d_is_dir(dentry)) |
| 527 | ret = simple_rmdir(d_inode(parent), dentry); |
| 528 | else |
| 529 | simple_unlink(d_inode(parent), dentry); |
| 530 | if (!ret) |
| 531 | d_delete(dentry); |
| 532 | dput(dentry); |
| 533 | } |
| 534 | return ret; |
| 535 | } |
| 536 | |
| 537 | /** |
| 538 | * debugfs_remove - removes a file or directory from the debugfs filesystem |
| 539 | * @dentry: a pointer to a the dentry of the file or directory to be |
| 540 | * removed. If this parameter is NULL or an error value, nothing |
| 541 | * will be done. |
| 542 | * |
| 543 | * This function removes a file or directory in debugfs that was previously |
| 544 | * created with a call to another debugfs function (like |
| 545 | * debugfs_create_file() or variants thereof.) |
| 546 | * |
| 547 | * This function is required to be called in order for the file to be |
| 548 | * removed, no automatic cleanup of files will happen when a module is |
| 549 | * removed, you are responsible here. |
| 550 | */ |
| 551 | void debugfs_remove(struct dentry *dentry) |
| 552 | { |
| 553 | struct dentry *parent; |
| 554 | int ret; |
| 555 | |
| 556 | if (IS_ERR_OR_NULL(dentry)) |
| 557 | return; |
| 558 | |
| 559 | parent = dentry->d_parent; |
| 560 | if (!parent || d_really_is_negative(parent)) |
| 561 | return; |
| 562 | |
| 563 | inode_lock(d_inode(parent)); |
| 564 | ret = __debugfs_remove(dentry, parent); |
| 565 | inode_unlock(d_inode(parent)); |
| 566 | if (!ret) |
| 567 | simple_release_fs(&debugfs_mount, &debugfs_mount_count); |
| 568 | } |
| 569 | EXPORT_SYMBOL_GPL(debugfs_remove); |
| 570 | |
| 571 | /** |
| 572 | * debugfs_remove_recursive - recursively removes a directory |
| 573 | * @dentry: a pointer to a the dentry of the directory to be removed. If this |
| 574 | * parameter is NULL or an error value, nothing will be done. |
| 575 | * |
| 576 | * This function recursively removes a directory tree in debugfs that |
| 577 | * was previously created with a call to another debugfs function |
| 578 | * (like debugfs_create_file() or variants thereof.) |
| 579 | * |
| 580 | * This function is required to be called in order for the file to be |
| 581 | * removed, no automatic cleanup of files will happen when a module is |
| 582 | * removed, you are responsible here. |
| 583 | */ |
| 584 | void debugfs_remove_recursive(struct dentry *dentry) |
| 585 | { |
| 586 | struct dentry *child, *parent; |
| 587 | |
| 588 | if (IS_ERR_OR_NULL(dentry)) |
| 589 | return; |
| 590 | |
| 591 | parent = dentry->d_parent; |
| 592 | if (!parent || d_really_is_negative(parent)) |
| 593 | return; |
| 594 | |
| 595 | parent = dentry; |
| 596 | down: |
| 597 | inode_lock(d_inode(parent)); |
| 598 | loop: |
| 599 | /* |
| 600 | * The parent->d_subdirs is protected by the d_lock. Outside that |
| 601 | * lock, the child can be unlinked and set to be freed which can |
| 602 | * use the d_u.d_child as the rcu head and corrupt this list. |
| 603 | */ |
| 604 | spin_lock(&parent->d_lock); |
| 605 | list_for_each_entry(child, &parent->d_subdirs, d_child) { |
| 606 | if (!simple_positive(child)) |
| 607 | continue; |
| 608 | |
| 609 | /* perhaps simple_empty(child) makes more sense */ |
| 610 | if (!list_empty(&child->d_subdirs)) { |
| 611 | spin_unlock(&parent->d_lock); |
| 612 | inode_unlock(d_inode(parent)); |
| 613 | parent = child; |
| 614 | goto down; |
| 615 | } |
| 616 | |
| 617 | spin_unlock(&parent->d_lock); |
| 618 | |
| 619 | if (!__debugfs_remove(child, parent)) |
| 620 | simple_release_fs(&debugfs_mount, &debugfs_mount_count); |
| 621 | |
| 622 | /* |
| 623 | * The parent->d_lock protects agaist child from unlinking |
| 624 | * from d_subdirs. When releasing the parent->d_lock we can |
| 625 | * no longer trust that the next pointer is valid. |
| 626 | * Restart the loop. We'll skip this one with the |
| 627 | * simple_positive() check. |
| 628 | */ |
| 629 | goto loop; |
| 630 | } |
| 631 | spin_unlock(&parent->d_lock); |
| 632 | |
| 633 | inode_unlock(d_inode(parent)); |
| 634 | child = parent; |
| 635 | parent = parent->d_parent; |
| 636 | inode_lock(d_inode(parent)); |
| 637 | |
| 638 | if (child != dentry) |
| 639 | /* go up */ |
| 640 | goto loop; |
| 641 | |
| 642 | if (!__debugfs_remove(child, parent)) |
| 643 | simple_release_fs(&debugfs_mount, &debugfs_mount_count); |
| 644 | inode_unlock(d_inode(parent)); |
| 645 | } |
| 646 | EXPORT_SYMBOL_GPL(debugfs_remove_recursive); |
| 647 | |
| 648 | /** |
| 649 | * debugfs_rename - rename a file/directory in the debugfs filesystem |
| 650 | * @old_dir: a pointer to the parent dentry for the renamed object. This |
| 651 | * should be a directory dentry. |
| 652 | * @old_dentry: dentry of an object to be renamed. |
| 653 | * @new_dir: a pointer to the parent dentry where the object should be |
| 654 | * moved. This should be a directory dentry. |
| 655 | * @new_name: a pointer to a string containing the target name. |
| 656 | * |
| 657 | * This function renames a file/directory in debugfs. The target must not |
| 658 | * exist for rename to succeed. |
| 659 | * |
| 660 | * This function will return a pointer to old_dentry (which is updated to |
| 661 | * reflect renaming) if it succeeds. If an error occurs, %NULL will be |
| 662 | * returned. |
| 663 | * |
| 664 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be |
| 665 | * returned. |
| 666 | */ |
| 667 | struct dentry *debugfs_rename(struct dentry *old_dir, struct dentry *old_dentry, |
| 668 | struct dentry *new_dir, const char *new_name) |
| 669 | { |
| 670 | int error; |
| 671 | struct dentry *dentry = NULL, *trap; |
| 672 | const char *old_name; |
| 673 | |
| 674 | trap = lock_rename(new_dir, old_dir); |
| 675 | /* Source or destination directories don't exist? */ |
| 676 | if (d_really_is_negative(old_dir) || d_really_is_negative(new_dir)) |
| 677 | goto exit; |
| 678 | /* Source does not exist, cyclic rename, or mountpoint? */ |
| 679 | if (d_really_is_negative(old_dentry) || old_dentry == trap || |
| 680 | d_mountpoint(old_dentry)) |
| 681 | goto exit; |
| 682 | dentry = lookup_one_len(new_name, new_dir, strlen(new_name)); |
| 683 | /* Lookup failed, cyclic rename or target exists? */ |
| 684 | if (IS_ERR(dentry) || dentry == trap || d_really_is_positive(dentry)) |
| 685 | goto exit; |
| 686 | |
| 687 | old_name = fsnotify_oldname_init(old_dentry->d_name.name); |
| 688 | |
| 689 | error = simple_rename(d_inode(old_dir), old_dentry, d_inode(new_dir), |
| 690 | dentry); |
| 691 | if (error) { |
| 692 | fsnotify_oldname_free(old_name); |
| 693 | goto exit; |
| 694 | } |
| 695 | d_move(old_dentry, dentry); |
| 696 | fsnotify_move(d_inode(old_dir), d_inode(new_dir), old_name, |
| 697 | d_is_dir(old_dentry), |
| 698 | NULL, old_dentry); |
| 699 | fsnotify_oldname_free(old_name); |
| 700 | unlock_rename(new_dir, old_dir); |
| 701 | dput(dentry); |
| 702 | return old_dentry; |
| 703 | exit: |
| 704 | if (dentry && !IS_ERR(dentry)) |
| 705 | dput(dentry); |
| 706 | unlock_rename(new_dir, old_dir); |
| 707 | return NULL; |
| 708 | } |
| 709 | EXPORT_SYMBOL_GPL(debugfs_rename); |
| 710 | |
| 711 | /** |
| 712 | * debugfs_initialized - Tells whether debugfs has been registered |
| 713 | */ |
| 714 | bool debugfs_initialized(void) |
| 715 | { |
| 716 | return debugfs_registered; |
| 717 | } |
| 718 | EXPORT_SYMBOL_GPL(debugfs_initialized); |
| 719 | |
| 720 | static int __init debugfs_init(void) |
| 721 | { |
| 722 | int retval; |
| 723 | |
| 724 | retval = sysfs_create_mount_point(kernel_kobj, "debug"); |
| 725 | if (retval) |
| 726 | return retval; |
| 727 | |
| 728 | retval = register_filesystem(&debug_fs_type); |
| 729 | if (retval) |
| 730 | sysfs_remove_mount_point(kernel_kobj, "debug"); |
| 731 | else |
| 732 | debugfs_registered = true; |
| 733 | |
| 734 | return retval; |
| 735 | } |
| 736 | core_initcall(debugfs_init); |
| 737 | |