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| 1 | /* | |||
| 2 | * file.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 | /* uncomment to get debug messages from the debug filesystem, ah the irony. */ | |||
| 17 | /* #define DEBUG */ | |||
| 18 | ||||
| 19 | #include <linux/config.h> | |||
| 20 | #include <linux/module.h> | |||
| 21 | #include <linux/fs.h> | |||
| 22 | #include <linux/mount.h> | |||
| 23 | #include <linux/pagemap.h> | |||
| 24 | #include <linux/init.h> | |||
| 25 | #include <linux/namei.h> | |||
| 26 | #include <linux/debugfs.h> | |||
| 27 | ||||
| 28 | #define DEBUGFS_MAGIC 0x64626720 | |||
| 29 | ||||
| 30 | /* declared over in file.c */ | |||
| 31 | extern struct file_operations debugfs_file_operations; | |||
| 32 | ||||
| 33 | static struct vfsmount *debugfs_mount; | |||
| 34 | static int debugfs_mount_count; | |||
| 35 | ||||
| 78 | 0 | 36 | static struct inode *debugfs_get_inode(struct super_block *sb, int mode, dev_t dev) | |
| 37 | { | |||
| 38 | struct inode *inode = new_inode(sb); | |||
| 39 | ||||
| 78 | 0 | - | 40 | if (inode) { |
| 41 | inode->i_mode = mode; | |||
| 42 | inode->i_uid = 0; | |||
| 43 | inode->i_gid = 0; | |||
| 44 | inode->i_blksize = PAGE_CACHE_SIZE; | |||
| 45 | inode->i_blocks = 0; | |||
| 46 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; | |||
| 47 | switch (mode & S_IFMT) { | |||
| 0 | - | 48 | default: | |
| 49 | init_special_inode(inode, mode, dev); | |||
| 0 | - | 50 | break; | |
| 66 | 51 | case S_IFREG: | ||
| 52 | inode->i_fop = &debugfs_file_operations; | |||
| 66 | 53 | break; | ||
| 12 | 54 | case S_IFDIR: | ||
| 55 | inode->i_op = &simple_dir_inode_operations; | |||
| 56 | inode->i_fop = &simple_dir_operations; | |||
| 57 | ||||
| 58 | /* directory inodes start off with i_nlink == 2 (for "." entry) */ | |||
| 59 | inode->i_nlink++; | |||
| 12 | 60 | break; | ||
| 61 | } | |||
| 62 | } | |||
| 78 | 63 | return inode; | ||
| 64 | } | |||
| 65 | ||||
| 66 | /* SMP-safe */ | |||
| 78 | 0 | 67 | static int debugfs_mknod(struct inode *dir, struct dentry *dentry, | |
| 68 | int mode, dev_t dev) | |||
| 69 | { | |||
| 70 | struct inode *inode = debugfs_get_inode(dir->i_sb, mode, dev); | |||
| 71 | int error = -EPERM; | |||
| 72 | ||||
| 0 | 78 | - | 73 | if (dentry->d_inode) |
| 0 | - | 74 | return -EEXIST; | |
| 75 | ||||
| 78 | 0 | - | 76 | if (inode) { |
| 77 | d_instantiate(dentry, inode); | |||
| 78 | dget(dentry); | |||
| 79 | error = 0; | |||
| 80 | } | |||
| 78 | 81 | return error; | ||
| 82 | } | |||
| 83 | ||||
| 12 | 0 | 84 | static int debugfs_mkdir(struct inode *dir, struct dentry *dentry, int mode) | |
| 85 | { | |||
| 86 | int res; | |||
| 87 | ||||
| 88 | mode = (mode & (S_IRWXUGO | S_ISVTX)) | S_IFDIR; | |||
| 89 | res = debugfs_mknod(dir, dentry, mode, 0); | |||
| 12 | 0 | - | 90 | if (!res) |
| 91 | dir->i_nlink++; | |||
| 12 | 92 | return res; | ||
| 93 | } | |||
| 94 | ||||
| 66 | 0 | 95 | static int debugfs_create(struct inode *dir, struct dentry *dentry, int mode) | |
| 96 | { | |||
| 97 | mode = (mode & S_IALLUGO) | S_IFREG; | |||
| 66 | 98 | return debugfs_mknod(dir, dentry, mode, 0); | ||
| 99 | } | |||
| 100 | ||||
| 0 | 0 | - | 101 | static inline int debugfs_positive(struct dentry *dentry) |
| 102 | { | |||
| 0 | - | 103 | return dentry->d_inode && !d_unhashed(dentry); | |
| 104 | } | |||
| 105 | ||||
| 6 | 0 | 106 | static int debug_fill_super(struct super_block *sb, void *data, int silent) | |
| 107 | { | |||
| 108 | static struct tree_descr debug_files[] = {{""}}; | |||
| 109 | ||||
| 6 | 110 | return simple_fill_super(sb, DEBUGFS_MAGIC, debug_files); | ||
| 111 | } | |||
| 112 | ||||
| 6 | 0 | 113 | static struct super_block *debug_get_sb(struct file_system_type *fs_type, | |
| 114 | int flags, const char *dev_name, | |||
| 115 | void *data) | |||
| 116 | { | |||
| 6 | 117 | return get_sb_single(fs_type, flags, data, debug_fill_super); | ||
| 118 | } | |||
| 119 | ||||
| 120 | static struct file_system_type debug_fs_type = { | |||
| 121 | .owner = THIS_MODULE, | |||
| 122 | .name = "debugfs", | |||
| 123 | .get_sb = debug_get_sb, | |||
| 124 | .kill_sb = kill_litter_super, | |||
| 125 | }; | |||
| 126 | ||||
| 78 | 0 | 127 | static int debugfs_create_by_name(const char *name, mode_t mode, | |
| 128 | struct dentry *parent, | |||
| 129 | struct dentry **dentry) | |||
| 130 | { | |||
| 131 | int error = 0; | |||
| 132 | ||||
| 133 | /* If the parent is not specified, we create it in the root. | |||
| 134 | * We need the root dentry to do this, which is in the super | |||
| 135 | * block. A pointer to that is in the struct vfsmount that we | |||
| 136 | * have around. | |||
| 137 | */ | |||
| 12 | 66 | 138 | if (!parent ) { | |
| 12 | 0 | - | 139 | if (debugfs_mount && debugfs_mount->mnt_sb) { |
| 12 | 139 | T && T | ||
| 0 | - | 139 | T && F | |
| 0 | - | 139 | F && _ | |
| 140 | parent = debugfs_mount->mnt_sb->s_root; | |||
| 141 | } | |||
| 142 | } | |||
| 0 | 78 | - | 143 | if (!parent) { |
| 144 | pr_debug("debugfs: Ah! can not find a parent!\n"); | |||
| 0 | 0 | - | 144 | do-while (0) |
| 0 | - | 145 | return -EFAULT; | |
| 146 | } | |||
| 147 | ||||
| 148 | *dentry = NULL; | |||
| 149 | mutex_lock(&parent->d_inode->i_mutex); | |||
| 150 | *dentry = lookup_one_len(name, parent, strlen(name)); | |||
| 78 | 0 | - | 151 | if (!IS_ERR(dentry)) { |
| 12 | 66 | 152 | if ((mode & S_IFMT) == S_IFDIR) | |
| 153 | error = debugfs_mkdir(parent->d_inode, *dentry, mode); | |||
| 154 | else | |||
| 155 | error = debugfs_create(parent->d_inode, *dentry, mode); | |||
| 156 | } else | |||
| 157 | error = PTR_ERR(dentry); | |||
| 158 | mutex_unlock(&parent->d_inode->i_mutex); | |||
| 159 | ||||
| 78 | 160 | return error; | ||
| 161 | } | |||
| 162 | ||||
| 163 | /** | |||
| 164 | * debugfs_create_file - create a file in the debugfs filesystem | |||
| 165 | * | |||
| 166 | * @name: a pointer to a string containing the name of the file to create. | |||
| 167 | * @mode: the permission that the file should have | |||
| 168 | * @parent: a pointer to the parent dentry for this file. This should be a | |||
| 169 | * directory dentry if set. If this paramater is NULL, then the | |||
| 170 | * file will be created in the root of the debugfs filesystem. | |||
| 171 | * @data: a pointer to something that the caller will want to get to later | |||
| 172 | * on. The inode.u.generic_ip pointer will point to this value on | |||
| 173 | * the open() call. | |||
| 174 | * @fops: a pointer to a struct file_operations that should be used for | |||
| 175 | * this file. | |||
| 176 | * | |||
| 177 | * This is the basic "create a file" function for debugfs. It allows for a | |||
| 178 | * wide range of flexibility in createing a file, or a directory (if you | |||
| 179 | * want to create a directory, the debugfs_create_dir() function is | |||
| 180 | * recommended to be used instead.) | |||
| 181 | * | |||
| 182 | * This function will return a pointer to a dentry if it succeeds. This | |||
| 183 | * pointer must be passed to the debugfs_remove() function when the file is | |||
| 184 | * to be removed (no automatic cleanup happens if your module is unloaded, | |||
| 185 | * you are responsible here.) If an error occurs, NULL will be returned. | |||
| 186 | * | |||
| 187 | * If debugfs is not enabled in the kernel, the value -ENODEV will be | |||
| 188 | * returned. It is not wise to check for this value, but rather, check for | |||
| 189 | * NULL or !NULL instead as to eliminate the need for #ifdef in the calling | |||
| 190 | * code. | |||
| 191 | */ | |||
| 78 | 0 | 192 | struct dentry *debugfs_create_file(const char *name, mode_t mode, | |
| 193 | struct dentry *parent, void *data, | |||
| 194 | struct file_operations *fops) | |||
| 195 | { | |||
| 196 | struct dentry *dentry = NULL; | |||
| 197 | int error; | |||
| 198 | ||||
| 199 | pr_debug("debugfs: creating file '%s'\n",name); | |||
| 0 | 78 | - | 199 | do-while (0) |
| 200 | ||||
| 201 | error = simple_pin_fs("debugfs", &debugfs_mount, &debugfs_mount_count); | |||
| 0 | 78 | - | 202 | if (error) |
| 0 | - | 203 | goto exit; | |
| 204 | ||||
| 205 | error = debugfs_create_by_name(name, mode, parent, &dentry); | |||
| 0 | 78 | - | 206 | if (error) { |
| 207 | dentry = NULL; | |||
| 0 | - | 208 | goto exit; | |
| 209 | } | |||
| 210 | ||||
| 78 | 0 | - | 211 | if (dentry->d_inode) { |
| 66 | 12 | 212 | if (data) | |
| 213 | dentry->d_inode->u.generic_ip = data; | |||
| 66 | 12 | 214 | if (fops) | |
| 215 | dentry->d_inode->i_fop = fops; | |||
| 216 | } | |||
| 217 | exit: | |||
| 78 | 218 | return dentry; | ||
| 219 | } | |||
| 220 | EXPORT_SYMBOL_GPL(debugfs_create_file); | |||
| 221 | ||||
| 222 | /** | |||
| 223 | * debugfs_create_dir - create a directory in the debugfs filesystem | |||
| 224 | * | |||
| 225 | * @name: a pointer to a string containing the name of the directory to | |||
| 226 | * create. | |||
| 227 | * @parent: a pointer to the parent dentry for this file. This should be a | |||
| 228 | * directory dentry if set. If this paramater is NULL, then the | |||
| 229 | * directory will be created in the root of the debugfs filesystem. | |||
| 230 | * | |||
| 231 | * This function creates a directory in debugfs with the given name. | |||
| 232 | * | |||
| 233 | * This function will return a pointer to a dentry if it succeeds. This | |||
| 234 | * pointer must be passed to the debugfs_remove() function when the file is | |||
| 235 | * to be removed (no automatic cleanup happens if your module is unloaded, | |||
| 236 | * you are responsible here.) If an error occurs, NULL will be returned. | |||
| 237 | * | |||
| 238 | * If debugfs is not enabled in the kernel, the value -ENODEV will be | |||
| 239 | * returned. It is not wise to check for this value, but rather, check for | |||
| 240 | * NULL or !NULL instead as to eliminate the need for #ifdef in the calling | |||
| 241 | * code. | |||
| 242 | */ | |||
| 12 | 0 | 243 | struct dentry *debugfs_create_dir(const char *name, struct dentry *parent) | |
| 244 | { | |||
| 245 | return debugfs_create_file(name, | |||
| 246 | S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO, | |||
| 12 | 247 | parent, NULL, NULL); | ||
| 248 | } | |||
| 249 | EXPORT_SYMBOL_GPL(debugfs_create_dir); | |||
| 250 | ||||
| 251 | /** | |||
| 252 | * debugfs_remove - removes a file or directory from the debugfs filesystem | |||
| 253 | * | |||
| 254 | * @dentry: a pointer to a the dentry of the file or directory to be | |||
| 255 | * removed. | |||
| 256 | * | |||
| 257 | * This function removes a file or directory in debugfs that was previously | |||
| 258 | * created with a call to another debugfs function (like | |||
| 259 | * debufs_create_file() or variants thereof.) | |||
| 260 | * | |||
| 261 | * This function is required to be called in order for the file to be | |||
| 262 | * removed, no automatic cleanup of files will happen when a module is | |||
| 263 | * removed, you are responsible here. | |||
| 264 | */ | |||
| 0 | 0 | - | 265 | void debugfs_remove(struct dentry *dentry) |
| 266 | { | |||
| 267 | struct dentry *parent; | |||
| 268 | ||||
| 0 | 0 | - | 269 | if (!dentry) |
| 0 | - | 270 | return; | |
| 271 | ||||
| 272 | parent = dentry->d_parent; | |||
| 0 | 0 | - | 273 | if (!parent || !parent->d_inode) |
| 0 | - | 273 | T || _ | |
| 0 | - | 273 | F || T | |
| 0 | - | 273 | F || F | |
| 0 | - | 274 | return; | |
| 275 | ||||
| 276 | mutex_lock(&parent->d_inode->i_mutex); | |||
| 0 | 0 | - | 277 | if (debugfs_positive(dentry)) { |
| 0 | 0 | - | 278 | if (dentry->d_inode) { |
| 0 | 0 | - | 279 | if (S_ISDIR(dentry->d_inode->i_mode)) |
| 280 | simple_rmdir(parent->d_inode, dentry); | |||
| 281 | else | |||
| 282 | simple_unlink(parent->d_inode, dentry); | |||
| 283 | dput(dentry); | |||
| 284 | } | |||
| 285 | } | |||
| 286 | mutex_unlock(&parent->d_inode->i_mutex); | |||
| 287 | simple_release_fs(&debugfs_mount, &debugfs_mount_count); | |||
| 288 | } | |||
| 289 | EXPORT_SYMBOL_GPL(debugfs_remove); | |||
| 290 | ||||
| 291 | static decl_subsys(debug, NULL, NULL); | |||
| 292 | ||||
| 6 | 0 | 293 | static int __init debugfs_init(void) | |
| 294 | { | |||
| 295 | int retval; | |||
| 296 | ||||
| 297 | kset_set_kset_s(&debug_subsys, kernel_subsys); | |||
| 298 | retval = subsystem_register(&debug_subsys); | |||
| 0 | 6 | - | 299 | if (retval) |
| 0 | - | 300 | return retval; | |
| 301 | ||||
| 302 | retval = register_filesystem(&debug_fs_type); | |||
| 0 | 6 | - | 303 | if (retval) |
| 304 | subsystem_unregister(&debug_subsys); | |||
| 6 | 305 | return retval; | ||
| 306 | } | |||
| 307 | ||||
| 0 | 0 | - | 308 | static void __exit debugfs_exit(void) |
| 309 | { | |||
| 310 | simple_release_fs(&debugfs_mount, &debugfs_mount_count); | |||
| 311 | unregister_filesystem(&debug_fs_type); | |||
| 312 | subsystem_unregister(&debug_subsys); | |||
| 313 | } | |||
| 314 | ||||
| 315 | core_initcall(debugfs_init); | |||
| 316 | module_exit(debugfs_exit); | |||
| 317 | MODULE_LICENSE("GPL"); | |||
| 318 | ||||
| ***TER 52% (46/89) of SOURCE FILE inode.c | ||||