| 1 | |
| 2 | * inode.c - part of debugfs, a tiny little debug file system
|
| 3 | *
|
| 4 | * Copyright (C) 2004 Greg Kroah-Hartman <[email protected]>
|
| 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/core-api/kernel-api.rst 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 | #include <linux/srcu.h>
|
| 31 |
|
| 32 | #include "internal.h"
|
| 33 |
|
| 34 | #define DEBUGFS_DEFAULT_MODE 0700
|
| 35 |
|
| 36 | DEFINE_SRCU(debugfs_srcu);
|
| 37 |
|
| 38 | static struct vfsmount *debugfs_mount;
|
| 39 | static int debugfs_mount_count;
|
| 40 | static bool debugfs_registered;
|
| 41 |
|
| 42 | static struct inode *debugfs_get_inode(struct super_block *sb)
|
| 43 | {
|
| 44 | struct inode *inode = new_inode(sb);
|
| 45 | if (inode) {
|
| 46 | inode->i_ino = get_next_ino();
|
| 47 | inode->i_atime = inode->i_mtime =
|
| 48 | inode->i_ctime = current_time(inode);
|
| 49 | }
|
| 50 | return inode;
|
| 51 | }
|
| 52 |
|
| 53 | struct debugfs_mount_opts {
|
| 54 | kuid_t uid;
|
| 55 | kgid_t gid;
|
| 56 | umode_t mode;
|
| 57 | };
|
| 58 |
|
| 59 | enum {
|
| 60 | Opt_uid,
|
| 61 | Opt_gid,
|
| 62 | Opt_mode,
|
| 63 | Opt_err
|
| 64 | };
|
| 65 |
|
| 66 | static const match_table_t tokens = {
|
| 67 | {Opt_uid, "uid=%u"},
|
| 68 | {Opt_gid, "gid=%u"},
|
| 69 | {Opt_mode, "mode=%o"},
|
| 70 | {Opt_err, NULL}
|
| 71 | };
|
| 72 |
|
| 73 | struct debugfs_fs_info {
|
| 74 | struct debugfs_mount_opts mount_opts;
|
| 75 | };
|
| 76 |
|
| 77 | static int debugfs_parse_options(char *data, struct debugfs_mount_opts *opts)
|
| 78 | {
|
| 79 | substring_t args[MAX_OPT_ARGS];
|
| 80 | int option;
|
| 81 | int token;
|
| 82 | kuid_t uid;
|
| 83 | kgid_t gid;
|
| 84 | char *p;
|
| 85 |
|
| 86 | opts->mode = DEBUGFS_DEFAULT_MODE;
|
| 87 |
|
| 88 | while ((p = strsep(&data, ",")) != NULL) {
|
| 89 | if (!*p)
|
| 90 | continue;
|
| 91 |
|
| 92 | token = match_token(p, tokens, args);
|
| 93 | switch (token) {
|
| 94 | case Opt_uid:
|
| 95 | if (match_int(&args[0], &option))
|
| 96 | return -EINVAL;
|
| 97 | uid = make_kuid(current_user_ns(), option);
|
| 98 | if (!uid_valid(uid))
|
| 99 | return -EINVAL;
|
| 100 | opts->uid = uid;
|
| 101 | break;
|
| 102 | case Opt_gid:
|
| 103 | if (match_int(&args[0], &option))
|
| 104 | return -EINVAL;
|
| 105 | gid = make_kgid(current_user_ns(), option);
|
| 106 | if (!gid_valid(gid))
|
| 107 | return -EINVAL;
|
| 108 | opts->gid = gid;
|
| 109 | break;
|
| 110 | case Opt_mode:
|
| 111 | if (match_octal(&args[0], &option))
|
| 112 | return -EINVAL;
|
| 113 | opts->mode = option & S_IALLUGO;
|
| 114 | break;
|
| 115 | |
| 116 | * We might like to report bad mount options here;
|
| 117 | * but traditionally debugfs has ignored all mount options
|
| 118 |
|
| 119 | }
|
| 120 | }
|
| 121 |
|
| 122 | return 0;
|
| 123 | }
|
| 124 |
|
| 125 | static int debugfs_apply_options(struct super_block *sb)
|
| 126 | {
|
| 127 | struct debugfs_fs_info *fsi = sb->s_fs_info;
|
| 128 | struct inode *inode = d_inode(sb->s_root);
|
| 129 | struct debugfs_mount_opts *opts = &fsi->mount_opts;
|
| 130 |
|
| 131 | inode->i_mode &= ~S_IALLUGO;
|
| 132 | inode->i_mode |= opts->mode;
|
| 133 |
|
| 134 | inode->i_uid = opts->uid;
|
| 135 | inode->i_gid = opts->gid;
|
| 136 |
|
| 137 | return 0;
|
| 138 | }
|
| 139 |
|
| 140 | static int debugfs_remount(struct super_block *sb, int *flags, char *data)
|
| 141 | {
|
| 142 | int err;
|
| 143 | struct debugfs_fs_info *fsi = sb->s_fs_info;
|
| 144 |
|
| 145 | sync_filesystem(sb);
|
| 146 | err = debugfs_parse_options(data, &fsi->mount_opts);
|
| 147 | if (err)
|
| 148 | goto fail;
|
| 149 |
|
| 150 | debugfs_apply_options(sb);
|
| 151 |
|
| 152 | fail:
|
| 153 | return err;
|
| 154 | }
|
| 155 |
|
| 156 | static int debugfs_show_options(struct seq_file *m, struct dentry *root)
|
| 157 | {
|
| 158 | struct debugfs_fs_info *fsi = root->d_sb->s_fs_info;
|
| 159 | struct debugfs_mount_opts *opts = &fsi->mount_opts;
|
| 160 |
|
| 161 | if (!uid_eq(opts->uid, GLOBAL_ROOT_UID))
|
| 162 | seq_printf(m, ",uid=%u",
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| 163 | from_kuid_munged(&init_user_ns, opts->uid));
|
| 164 | if (!gid_eq(opts->gid, GLOBAL_ROOT_GID))
|
| 165 | seq_printf(m, ",gid=%u",
|
| 166 | from_kgid_munged(&init_user_ns, opts->gid));
|
| 167 | if (opts->mode != DEBUGFS_DEFAULT_MODE)
|
| 168 | seq_printf(m, ",mode=%o", opts->mode);
|
| 169 |
|
| 170 | return 0;
|
| 171 | }
|
| 172 |
|
| 173 | static void debugfs_evict_inode(struct inode *inode)
|
| 174 | {
|
| 175 | truncate_inode_pages_final(&inode->i_data);
|
| 176 | clear_inode(inode);
|
| 177 | if (S_ISLNK(inode->i_mode))
|
| 178 | kfree(inode->i_link);
|
| 179 | }
|
| 180 |
|
| 181 | static const struct super_operations debugfs_super_operations = {
|
| 182 | .statfs = simple_statfs,
|
| 183 | .remount_fs = debugfs_remount,
|
| 184 | .show_options = debugfs_show_options,
|
| 185 | .evict_inode = debugfs_evict_inode,
|
| 186 | };
|
| 187 |
|
| 188 | static struct vfsmount *debugfs_automount(struct path *path)
|
| 189 | {
|
| 190 | debugfs_automount_t f;
|
| 191 | f = (debugfs_automount_t)path->dentry->d_fsdata;
|
| 192 | return f(path->dentry, d_inode(path->dentry)->i_private);
|
| 193 | }
|
| 194 |
|
| 195 | static const struct dentry_operations debugfs_dops = {
|
| 196 | .d_delete = always_delete_dentry,
|
| 197 | .d_automount = debugfs_automount,
|
| 198 | };
|
| 199 |
|
| 200 | static int debug_fill_super(struct super_block *sb, void *data, int silent)
|
| 201 | {
|
| 202 | static const struct tree_descr debug_files[] = {{""}};
|
| 203 | struct debugfs_fs_info *fsi;
|
| 204 | int err;
|
| 205 |
|
| 206 | fsi = kzalloc(sizeof(struct debugfs_fs_info), GFP_KERNEL);
|
| 207 | sb->s_fs_info = fsi;
|
| 208 | if (!fsi) {
|
| 209 | err = -ENOMEM;
|
| 210 | goto fail;
|
| 211 | }
|
| 212 |
|
| 213 | err = debugfs_parse_options(data, &fsi->mount_opts);
|
| 214 | if (err)
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| 215 | goto fail;
|
| 216 |
|
| 217 | err = simple_fill_super(sb, DEBUGFS_MAGIC, debug_files);
|
| 218 | if (err)
|
| 219 | goto fail;
|
| 220 |
|
| 221 | sb->s_op = &debugfs_super_operations;
|
| 222 | sb->s_d_op = &debugfs_dops;
|
| 223 |
|
| 224 | debugfs_apply_options(sb);
|
| 225 |
|
| 226 | return 0;
|
| 227 |
|
| 228 | fail:
|
| 229 | kfree(fsi);
|
| 230 | sb->s_fs_info = NULL;
|
| 231 | return err;
|
| 232 | }
|
| 233 |
|
| 234 | static struct dentry *debug_mount(struct file_system_type *fs_type,
|
| 235 | int flags, const char *dev_name,
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| 236 | void *data)
|
| 237 | {
|
| 238 | return mount_single(fs_type, flags, data, debug_fill_super);
|
| 239 | }
|
| 240 |
|
| 241 | static struct file_system_type debug_fs_type = {
|
| 242 | .owner = THIS_MODULE,
|
| 243 | .name = "debugfs",
|
| 244 | .mount = debug_mount,
|
| 245 | .kill_sb = kill_litter_super,
|
| 246 | };
|
| 247 | MODULE_ALIAS_FS("debugfs");
|
| 248 |
|
| 249 | |
| 250 | * debugfs_lookup() - look up an existing debugfs file
|
| 251 | * @name: a pointer to a string containing the name of the file to look up.
|
| 252 | * @parent: a pointer to the parent dentry of the file.
|
| 253 | *
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| 254 | * This function will return a pointer to a dentry if it succeeds. If the file
|
| 255 | * doesn't exist or an error occurs, %NULL will be returned. The returned
|
| 256 | * dentry must be passed to dput() when it is no longer needed.
|
| 257 | *
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| 258 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be
|
| 259 | * returned.
|
| 260 |
|
| 261 | struct dentry *debugfs_lookup(const char *name, struct dentry *parent)
|
| 262 | {
|
| 263 | struct dentry *dentry;
|
| 264 |
|
| 265 | if (IS_ERR(parent))
|
| 266 | return NULL;
|
| 267 |
|
| 268 | if (!parent)
|
| 269 | parent = debugfs_mount->mnt_root;
|
| 270 |
|
| 271 | inode_lock(d_inode(parent));
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| 272 | dentry = lookup_one_len(name, parent, strlen(name));
|
| 273 | inode_unlock(d_inode(parent));
|
| 274 |
|
| 275 | if (IS_ERR(dentry))
|
| 276 | return NULL;
|
| 277 | if (!d_really_is_positive(dentry)) {
|
| 278 | dput(dentry);
|
| 279 | return NULL;
|
| 280 | }
|
| 281 | return dentry;
|
| 282 | }
|
| 283 | EXPORT_SYMBOL_GPL(debugfs_lookup);
|
| 284 |
|
| 285 | static struct dentry *start_creating(const char *name, struct dentry *parent)
|
| 286 | {
|
| 287 | struct dentry *dentry;
|
| 288 | int error;
|
| 289 |
|
| 290 | pr_debug("debugfs: creating file '%s'\n",name);
|
| 291 |
|
| 292 | if (IS_ERR(parent))
|
| 293 | return parent;
|
| 294 |
|
| 295 | error = simple_pin_fs(&debug_fs_type, &debugfs_mount,
|
| 296 | &debugfs_mount_count);
|
| 297 | if (error)
|
| 298 | return ERR_PTR(error);
|
| 299 |
|
| 300 | |
| 301 | * We need the root dentry to do this, which is in the super
|
| 302 | * block. A pointer to that is in the struct vfsmount that we
|
| 303 | * have around.
|
| 304 |
|
| 305 | if (!parent)
|
| 306 | parent = debugfs_mount->mnt_root;
|
| 307 |
|
| 308 | inode_lock(d_inode(parent));
|
| 309 | dentry = lookup_one_len(name, parent, strlen(name));
|
| 310 | if (!IS_ERR(dentry) && d_really_is_positive(dentry)) {
|
| 311 | dput(dentry);
|
| 312 | dentry = ERR_PTR(-EEXIST);
|
| 313 | }
|
| 314 |
|
| 315 | if (IS_ERR(dentry)) {
|
| 316 | inode_unlock(d_inode(parent));
|
| 317 | simple_release_fs(&debugfs_mount, &debugfs_mount_count);
|
| 318 | }
|
| 319 |
|
| 320 | return dentry;
|
| 321 | }
|
| 322 |
|
| 323 | static struct dentry *failed_creating(struct dentry *dentry)
|
| 324 | {
|
| 325 | inode_unlock(d_inode(dentry->d_parent));
|
| 326 | dput(dentry);
|
| 327 | simple_release_fs(&debugfs_mount, &debugfs_mount_count);
|
| 328 | return NULL;
|
| 329 | }
|
| 330 |
|
| 331 | static struct dentry *end_creating(struct dentry *dentry)
|
| 332 | {
|
| 333 | inode_unlock(d_inode(dentry->d_parent));
|
| 334 | return dentry;
|
| 335 | }
|
| 336 |
|
| 337 | static struct dentry *__debugfs_create_file(const char *name, umode_t mode,
|
| 338 | struct dentry *parent, void *data,
|
| 339 | const struct file_operations *proxy_fops,
|
| 340 | const struct file_operations *real_fops)
|
| 341 | {
|
| 342 | struct dentry *dentry;
|
| 343 | struct inode *inode;
|
| 344 |
|
| 345 | if (!(mode & S_IFMT))
|
| 346 | mode |= S_IFREG;
|
| 347 | BUG_ON(!S_ISREG(mode));
|
| 348 | dentry = start_creating(name, parent);
|
| 349 |
|
| 350 | if (IS_ERR(dentry))
|
| 351 | return NULL;
|
| 352 |
|
| 353 | inode = debugfs_get_inode(dentry->d_sb);
|
| 354 | if (unlikely(!inode))
|
| 355 | return failed_creating(dentry);
|
| 356 |
|
| 357 | inode->i_mode = mode;
|
| 358 | inode->i_private = data;
|
| 359 |
|
| 360 | inode->i_fop = proxy_fops;
|
| 361 | dentry->d_fsdata = (void *)real_fops;
|
| 362 |
|
| 363 | d_instantiate(dentry, inode);
|
| 364 | fsnotify_create(d_inode(dentry->d_parent), dentry);
|
| 365 | return end_creating(dentry);
|
| 366 | }
|
| 367 |
|
| 368 | |
| 369 | * debugfs_create_file - create a file in the debugfs filesystem
|
| 370 | * @name: a pointer to a string containing the name of the file to create.
|
| 371 | * @mode: the permission that the file should have.
|
| 372 | * @parent: a pointer to the parent dentry for this file. This should be a
|
| 373 | * directory dentry if set. If this parameter is NULL, then the
|
| 374 | * file will be created in the root of the debugfs filesystem.
|
| 375 | * @data: a pointer to something that the caller will want to get to later
|
| 376 | * on. The inode.i_private pointer will point to this value on
|
| 377 | * the open() call.
|
| 378 | * @fops: a pointer to a struct file_operations that should be used for
|
| 379 | * this file.
|
| 380 | *
|
| 381 | * This is the basic "create a file" function for debugfs. It allows for a
|
| 382 | * wide range of flexibility in creating a file, or a directory (if you want
|
| 383 | * to create a directory, the debugfs_create_dir() function is
|
| 384 | * recommended to be used instead.)
|
| 385 | *
|
| 386 | * This function will return a pointer to a dentry if it succeeds. This
|
| 387 | * pointer must be passed to the debugfs_remove() function when the file is
|
| 388 | * to be removed (no automatic cleanup happens if your module is unloaded,
|
| 389 | * you are responsible here.) If an error occurs, %NULL will be returned.
|
| 390 | *
|
| 391 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be
|
| 392 | * returned.
|
| 393 |
|
| 394 | struct dentry *debugfs_create_file(const char *name, umode_t mode,
|
| 395 | struct dentry *parent, void *data,
|
| 396 | const struct file_operations *fops)
|
| 397 | {
|
| 398 |
|
| 399 | return __debugfs_create_file(name, mode, parent, data,
|
| 400 | fops ? &debugfs_full_proxy_file_operations :
|
| 401 | &debugfs_noop_file_operations,
|
| 402 | fops);
|
| 403 | }
|
| 404 | EXPORT_SYMBOL_GPL(debugfs_create_file);
|
| 405 |
|
| 406 | |
| 407 | * debugfs_create_file_unsafe - create a file in the debugfs filesystem
|
| 408 | * @name: a pointer to a string containing the name of the file to create.
|
| 409 | * @mode: the permission that the file should have.
|
| 410 | * @parent: a pointer to the parent dentry for this file. This should be a
|
| 411 | * directory dentry if set. If this parameter is NULL, then the
|
| 412 | * file will be created in the root of the debugfs filesystem.
|
| 413 | * @data: a pointer to something that the caller will want to get to later
|
| 414 | * on. The inode.i_private pointer will point to this value on
|
| 415 | * the open() call.
|
| 416 | * @fops: a pointer to a struct file_operations that should be used for
|
| 417 | * this file.
|
| 418 | *
|
| 419 | * debugfs_create_file_unsafe() is completely analogous to
|
| 420 | * debugfs_create_file(), the only difference being that the fops
|
| 421 | * handed it will not get protected against file removals by the
|
| 422 | * debugfs core.
|
| 423 | *
|
| 424 | * It is your responsibility to protect your struct file_operation
|
| 425 | * methods against file removals by means of debugfs_use_file_start()
|
| 426 | * and debugfs_use_file_finish(). ->open() is still protected by
|
| 427 | * debugfs though.
|
| 428 | *
|
| 429 | * Any struct file_operations defined by means of
|
| 430 | * DEFINE_DEBUGFS_ATTRIBUTE() is protected against file removals and
|
| 431 | * thus, may be used here.
|
| 432 |
|
| 433 | struct dentry *debugfs_create_file_unsafe(const char *name, umode_t mode,
|
| 434 | struct dentry *parent, void *data,
|
| 435 | const struct file_operations *fops)
|
| 436 | {
|
| 437 |
|
| 438 | return __debugfs_create_file(name, mode, parent, data,
|
| 439 | fops ? &debugfs_open_proxy_file_operations :
|
| 440 | &debugfs_noop_file_operations,
|
| 441 | fops);
|
| 442 | }
|
| 443 | EXPORT_SYMBOL_GPL(debugfs_create_file_unsafe);
|
| 444 |
|
| 445 | |
| 446 | * debugfs_create_file_size - create a file in the debugfs filesystem
|
| 447 | * @name: a pointer to a string containing the name of the file to create.
|
| 448 | * @mode: the permission that the file should have.
|
| 449 | * @parent: a pointer to the parent dentry for this file. This should be a
|
| 450 | * directory dentry if set. If this parameter is NULL, then the
|
| 451 | * file will be created in the root of the debugfs filesystem.
|
| 452 | * @data: a pointer to something that the caller will want to get to later
|
| 453 | * on. The inode.i_private pointer will point to this value on
|
| 454 | * the open() call.
|
| 455 | * @fops: a pointer to a struct file_operations that should be used for
|
| 456 | * this file.
|
| 457 | * @file_size: initial file size
|
| 458 | *
|
| 459 | * This is the basic "create a file" function for debugfs. It allows for a
|
| 460 | * wide range of flexibility in creating a file, or a directory (if you want
|
| 461 | * to create a directory, the debugfs_create_dir() function is
|
| 462 | * recommended to be used instead.)
|
| 463 | *
|
| 464 | * This function will return a pointer to a dentry if it succeeds. This
|
| 465 | * pointer must be passed to the debugfs_remove() function when the file is
|
| 466 | * to be removed (no automatic cleanup happens if your module is unloaded,
|
| 467 | * you are responsible here.) If an error occurs, %NULL will be returned.
|
| 468 | *
|
| 469 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be
|
| 470 | * returned.
|
| 471 |
|
| 472 | struct dentry *debugfs_create_file_size(const char *name, umode_t mode,
|
| 473 | struct dentry *parent, void *data,
|
| 474 | const struct file_operations *fops,
|
| 475 | loff_t file_size)
|
| 476 | {
|
| 477 | struct dentry *de = debugfs_create_file(name, mode, parent, data, fops);
|
| 478 |
|
| 479 | if (de)
|
| 480 | d_inode(de)->i_size = file_size;
|
| 481 | return de;
|
| 482 | }
|
| 483 | EXPORT_SYMBOL_GPL(debugfs_create_file_size);
|
| 484 |
|
| 485 | |
| 486 | * debugfs_create_dir - create a directory in the debugfs filesystem
|
| 487 | * @name: a pointer to a string containing the name of the directory to
|
| 488 | * create.
|
| 489 | * @parent: a pointer to the parent dentry for this file. This should be a
|
| 490 | * directory dentry if set. If this parameter is NULL, then the
|
| 491 | * directory will be created in the root of the debugfs filesystem.
|
| 492 | *
|
| 493 | * This function creates a directory in debugfs with the given name.
|
| 494 | *
|
| 495 | * This function will return a pointer to a dentry if it succeeds. This
|
| 496 | * pointer must be passed to the debugfs_remove() function when the file is
|
| 497 | * to be removed (no automatic cleanup happens if your module is unloaded,
|
| 498 | * you are responsible here.) If an error occurs, %NULL will be returned.
|
| 499 | *
|
| 500 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be
|
| 501 | * returned.
|
| 502 |
|
| 503 | struct dentry *debugfs_create_dir(const char *name, struct dentry *parent)
|
| 504 | {
|
| 505 | struct dentry *dentry = start_creating(name, parent);
|
| 506 | struct inode *inode;
|
| 507 |
|
| 508 | if (IS_ERR(dentry))
|
| 509 | return NULL;
|
| 510 |
|
| 511 | inode = debugfs_get_inode(dentry->d_sb);
|
| 512 | if (unlikely(!inode))
|
| 513 | return failed_creating(dentry);
|
| 514 |
|
| 515 | inode->i_mode = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO;
|
| 516 | inode->i_op = &simple_dir_inode_operations;
|
| 517 | inode->i_fop = &simple_dir_operations;
|
| 518 |
|
| 519 |
|
| 520 | inc_nlink(inode);
|
| 521 | d_instantiate(dentry, inode);
|
| 522 | inc_nlink(d_inode(dentry->d_parent));
|
| 523 | fsnotify_mkdir(d_inode(dentry->d_parent), dentry);
|
| 524 | return end_creating(dentry);
|
| 525 | }
|
| 526 | EXPORT_SYMBOL_GPL(debugfs_create_dir);
|
| 527 |
|
| 528 | |
| 529 | * debugfs_create_automount - create automount point in the debugfs filesystem
|
| 530 | * @name: a pointer to a string containing the name of the file to create.
|
| 531 | * @parent: a pointer to the parent dentry for this file. This should be a
|
| 532 | * directory dentry if set. If this parameter is NULL, then the
|
| 533 | * file will be created in the root of the debugfs filesystem.
|
| 534 | * @f: function to be called when pathname resolution steps on that one.
|
| 535 | * @data: opaque argument to pass to f().
|
| 536 | *
|
| 537 | * @f should return what ->d_automount() would.
|
| 538 |
|
| 539 | struct dentry *debugfs_create_automount(const char *name,
|
| 540 | struct dentry *parent,
|
| 541 | debugfs_automount_t f,
|
| 542 | void *data)
|
| 543 | {
|
| 544 | struct dentry *dentry = start_creating(name, parent);
|
| 545 | struct inode *inode;
|
| 546 |
|
| 547 | if (IS_ERR(dentry))
|
| 548 | return NULL;
|
| 549 |
|
| 550 | inode = debugfs_get_inode(dentry->d_sb);
|
| 551 | if (unlikely(!inode))
|
| 552 | return failed_creating(dentry);
|
| 553 |
|
| 554 | make_empty_dir_inode(inode);
|
| 555 | inode->i_flags |= S_AUTOMOUNT;
|
| 556 | inode->i_private = data;
|
| 557 | dentry->d_fsdata = (void *)f;
|
| 558 |
|
| 559 | inc_nlink(inode);
|
| 560 | d_instantiate(dentry, inode);
|
| 561 | inc_nlink(d_inode(dentry->d_parent));
|
| 562 | fsnotify_mkdir(d_inode(dentry->d_parent), dentry);
|
| 563 | return end_creating(dentry);
|
| 564 | }
|
| 565 | EXPORT_SYMBOL(debugfs_create_automount);
|
| 566 |
|
| 567 | |
| 568 | * debugfs_create_symlink- create a symbolic link in the debugfs filesystem
|
| 569 | * @name: a pointer to a string containing the name of the symbolic link to
|
| 570 | * create.
|
| 571 | * @parent: a pointer to the parent dentry for this symbolic link. This
|
| 572 | * should be a directory dentry if set. If this parameter is NULL,
|
| 573 | * then the symbolic link will be created in the root of the debugfs
|
| 574 | * filesystem.
|
| 575 | * @target: a pointer to a string containing the path to the target of the
|
| 576 | * symbolic link.
|
| 577 | *
|
| 578 | * This function creates a symbolic link with the given name in debugfs that
|
| 579 | * links to the given target path.
|
| 580 | *
|
| 581 | * This function will return a pointer to a dentry if it succeeds. This
|
| 582 | * pointer must be passed to the debugfs_remove() function when the symbolic
|
| 583 | * link is to be removed (no automatic cleanup happens if your module is
|
| 584 | * unloaded, you are responsible here.) If an error occurs, %NULL will be
|
| 585 | * returned.
|
| 586 | *
|
| 587 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be
|
| 588 | * returned.
|
| 589 |
|
| 590 | struct dentry *debugfs_create_symlink(const char *name, struct dentry *parent,
|
| 591 | const char *target)
|
| 592 | {
|
| 593 | struct dentry *dentry;
|
| 594 | struct inode *inode;
|
| 595 | char *link = kstrdup(target, GFP_KERNEL);
|
| 596 | if (!link)
|
| 597 | return NULL;
|
| 598 |
|
| 599 | dentry = start_creating(name, parent);
|
| 600 | if (IS_ERR(dentry)) {
|
| 601 | kfree(link);
|
| 602 | return NULL;
|
| 603 | }
|
| 604 |
|
| 605 | inode = debugfs_get_inode(dentry->d_sb);
|
| 606 | if (unlikely(!inode)) {
|
| 607 | kfree(link);
|
| 608 | return failed_creating(dentry);
|
| 609 | }
|
| 610 | inode->i_mode = S_IFLNK | S_IRWXUGO;
|
| 611 | inode->i_op = &simple_symlink_inode_operations;
|
| 612 | inode->i_link = link;
|
| 613 | d_instantiate(dentry, inode);
|
| 614 | return end_creating(dentry);
|
| 615 | }
|
| 616 | EXPORT_SYMBOL_GPL(debugfs_create_symlink);
|
| 617 |
|
| 618 | static int __debugfs_remove(struct dentry *dentry, struct dentry *parent)
|
| 619 | {
|
| 620 | int ret = 0;
|
| 621 |
|
| 622 | if (simple_positive(dentry)) {
|
| 623 | dget(dentry);
|
| 624 | if (d_is_dir(dentry))
|
| 625 | ret = simple_rmdir(d_inode(parent), dentry);
|
| 626 | else
|
| 627 | simple_unlink(d_inode(parent), dentry);
|
| 628 | if (!ret)
|
| 629 | d_delete(dentry);
|
| 630 | dput(dentry);
|
| 631 | }
|
| 632 | return ret;
|
| 633 | }
|
| 634 |
|
| 635 | |
| 636 | * debugfs_remove - removes a file or directory from the debugfs filesystem
|
| 637 | * @dentry: a pointer to a the dentry of the file or directory to be
|
| 638 | * removed. If this parameter is NULL or an error value, nothing
|
| 639 | * will be done.
|
| 640 | *
|
| 641 | * This function removes a file or directory in debugfs that was previously
|
| 642 | * created with a call to another debugfs function (like
|
| 643 | * debugfs_create_file() or variants thereof.)
|
| 644 | *
|
| 645 | * This function is required to be called in order for the file to be
|
| 646 | * removed, no automatic cleanup of files will happen when a module is
|
| 647 | * removed, you are responsible here.
|
| 648 |
|
| 649 | void debugfs_remove(struct dentry *dentry)
|
| 650 | {
|
| 651 | struct dentry *parent;
|
| 652 | int ret;
|
| 653 |
|
| 654 | if (IS_ERR_OR_NULL(dentry))
|
| 655 | return;
|
| 656 |
|
| 657 | parent = dentry->d_parent;
|
| 658 | inode_lock(d_inode(parent));
|
| 659 | ret = __debugfs_remove(dentry, parent);
|
| 660 | inode_unlock(d_inode(parent));
|
| 661 | if (!ret)
|
| 662 | simple_release_fs(&debugfs_mount, &debugfs_mount_count);
|
| 663 |
|
| 664 | synchronize_srcu(&debugfs_srcu);
|
| 665 | }
|
| 666 | EXPORT_SYMBOL_GPL(debugfs_remove);
|
| 667 |
|
| 668 | |
| 669 | * debugfs_remove_recursive - recursively removes a directory
|
| 670 | * @dentry: a pointer to a the dentry of the directory to be removed. If this
|
| 671 | * parameter is NULL or an error value, nothing will be done.
|
| 672 | *
|
| 673 | * This function recursively removes a directory tree in debugfs that
|
| 674 | * was previously created with a call to another debugfs function
|
| 675 | * (like debugfs_create_file() or variants thereof.)
|
| 676 | *
|
| 677 | * This function is required to be called in order for the file to be
|
| 678 | * removed, no automatic cleanup of files will happen when a module is
|
| 679 | * removed, you are responsible here.
|
| 680 |
|
| 681 | void debugfs_remove_recursive(struct dentry *dentry)
|
| 682 | {
|
| 683 | struct dentry *child, *parent;
|
| 684 |
|
| 685 | if (IS_ERR_OR_NULL(dentry))
|
| 686 | return;
|
| 687 |
|
| 688 | parent = dentry;
|
| 689 | down:
|
| 690 | inode_lock(d_inode(parent));
|
| 691 | loop:
|
| 692 | |
| 693 | * The parent->d_subdirs is protected by the d_lock. Outside that
|
| 694 | * lock, the child can be unlinked and set to be freed which can
|
| 695 | * use the d_u.d_child as the rcu head and corrupt this list.
|
| 696 |
|
| 697 | spin_lock(&parent->d_lock);
|
| 698 | list_for_each_entry(child, &parent->d_subdirs, d_child) {
|
| 699 | if (!simple_positive(child))
|
| 700 | continue;
|
| 701 |
|
| 702 |
|
| 703 | if (!list_empty(&child->d_subdirs)) {
|
| 704 | spin_unlock(&parent->d_lock);
|
| 705 | inode_unlock(d_inode(parent));
|
| 706 | parent = child;
|
| 707 | goto down;
|
| 708 | }
|
| 709 |
|
| 710 | spin_unlock(&parent->d_lock);
|
| 711 |
|
| 712 | if (!__debugfs_remove(child, parent))
|
| 713 | simple_release_fs(&debugfs_mount, &debugfs_mount_count);
|
| 714 |
|
| 715 | |
| 716 | * The parent->d_lock protects agaist child from unlinking
|
| 717 | * from d_subdirs. When releasing the parent->d_lock we can
|
| 718 | * no longer trust that the next pointer is valid.
|
| 719 | * Restart the loop. We'll skip this one with the
|
| 720 | * simple_positive() check.
|
| 721 |
|
| 722 | goto loop;
|
| 723 | }
|
| 724 | spin_unlock(&parent->d_lock);
|
| 725 |
|
| 726 | inode_unlock(d_inode(parent));
|
| 727 | child = parent;
|
| 728 | parent = parent->d_parent;
|
| 729 | inode_lock(d_inode(parent));
|
| 730 |
|
| 731 | if (child != dentry)
|
| 732 |
|
| 733 | goto loop;
|
| 734 |
|
| 735 | if (!__debugfs_remove(child, parent))
|
| 736 | simple_release_fs(&debugfs_mount, &debugfs_mount_count);
|
| 737 | inode_unlock(d_inode(parent));
|
| 738 |
|
| 739 | synchronize_srcu(&debugfs_srcu);
|
| 740 | }
|
| 741 | EXPORT_SYMBOL_GPL(debugfs_remove_recursive);
|
| 742 |
|
| 743 | |
| 744 | * debugfs_rename - rename a file/directory in the debugfs filesystem
|
| 745 | * @old_dir: a pointer to the parent dentry for the renamed object. This
|
| 746 | * should be a directory dentry.
|
| 747 | * @old_dentry: dentry of an object to be renamed.
|
| 748 | * @new_dir: a pointer to the parent dentry where the object should be
|
| 749 | * moved. This should be a directory dentry.
|
| 750 | * @new_name: a pointer to a string containing the target name.
|
| 751 | *
|
| 752 | * This function renames a file/directory in debugfs. The target must not
|
| 753 | * exist for rename to succeed.
|
| 754 | *
|
| 755 | * This function will return a pointer to old_dentry (which is updated to
|
| 756 | * reflect renaming) if it succeeds. If an error occurs, %NULL will be
|
| 757 | * returned.
|
| 758 | *
|
| 759 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be
|
| 760 | * returned.
|
| 761 |
|
| 762 | struct dentry *debugfs_rename(struct dentry *old_dir, struct dentry *old_dentry,
|
| 763 | struct dentry *new_dir, const char *new_name)
|
| 764 | {
|
| 765 | int error;
|
| 766 | struct dentry *dentry = NULL, *trap;
|
| 767 | struct name_snapshot old_name;
|
| 768 |
|
| 769 | trap = lock_rename(new_dir, old_dir);
|
| 770 |
|
| 771 | if (d_really_is_negative(old_dir) || d_really_is_negative(new_dir))
|
| 772 | goto exit;
|
| 773 |
|
| 774 | if (d_really_is_negative(old_dentry) || old_dentry == trap ||
|
| 775 | d_mountpoint(old_dentry))
|
| 776 | goto exit;
|
| 777 | dentry = lookup_one_len(new_name, new_dir, strlen(new_name));
|
| 778 |
|
| 779 | if (IS_ERR(dentry) || dentry == trap || d_really_is_positive(dentry))
|
| 780 | goto exit;
|
| 781 |
|
| 782 | take_dentry_name_snapshot(&old_name, old_dentry);
|
| 783 |
|
| 784 | error = simple_rename(d_inode(old_dir), old_dentry, d_inode(new_dir),
|
| 785 | dentry, 0);
|
| 786 | if (error) {
|
| 787 | release_dentry_name_snapshot(&old_name);
|
| 788 | goto exit;
|
| 789 | }
|
| 790 | d_move(old_dentry, dentry);
|
| 791 | fsnotify_move(d_inode(old_dir), d_inode(new_dir), old_name.name,
|
| 792 | d_is_dir(old_dentry),
|
| 793 | NULL, old_dentry);
|
| 794 | release_dentry_name_snapshot(&old_name);
|
| 795 | unlock_rename(new_dir, old_dir);
|
| 796 | dput(dentry);
|
| 797 | return old_dentry;
|
| 798 | exit:
|
| 799 | if (dentry && !IS_ERR(dentry))
|
| 800 | dput(dentry);
|
| 801 | unlock_rename(new_dir, old_dir);
|
| 802 | return NULL;
|
| 803 | }
|
| 804 | EXPORT_SYMBOL_GPL(debugfs_rename);
|
| 805 |
|
| 806 | |
| 807 | * debugfs_initialized - Tells whether debugfs has been registered
|
| 808 |
|
| 809 | bool debugfs_initialized(void)
|
| 810 | {
|
| 811 | return debugfs_registered;
|
| 812 | }
|
| 813 | EXPORT_SYMBOL_GPL(debugfs_initialized);
|
| 814 |
|
| 815 | static int __init debugfs_init(void)
|
| 816 | {
|
| 817 | int retval;
|
| 818 |
|
| 819 | retval = sysfs_create_mount_point(kernel_kobj, "debug");
|
| 820 | if (retval)
|
| 821 | return retval;
|
| 822 |
|
| 823 | retval = register_filesystem(&debug_fs_type);
|
| 824 | if (retval)
|
| 825 | sysfs_remove_mount_point(kernel_kobj, "debug");
|
| 826 | else
|
| 827 | debugfs_registered = true;
|
| 828 |
|
| 829 | return retval;
|
| 830 | }
|
| 831 | core_initcall(debugfs_init);
|
| 832 |
|