diff options
| -rw-r--r-- | fs/debugfs/file.c | 12 | ||||
| -rw-r--r-- | fs/debugfs/inode.c | 76 | ||||
| -rw-r--r-- | include/linux/debugfs.h | 10 |
3 files changed, 94 insertions, 4 deletions
diff --git a/fs/debugfs/file.c b/fs/debugfs/file.c index 8d130cc85322..682f928b7f4d 100644 --- a/fs/debugfs/file.c +++ b/fs/debugfs/file.c @@ -16,6 +16,7 @@ #include <linux/module.h> #include <linux/fs.h> #include <linux/pagemap.h> +#include <linux/namei.h> #include <linux/debugfs.h> static ssize_t default_read_file(struct file *file, char __user *buf, @@ -44,6 +45,17 @@ const struct file_operations debugfs_file_operations = { .open = default_open, }; +static void *debugfs_follow_link(struct dentry *dentry, struct nameidata *nd) +{ + nd_set_link(nd, dentry->d_inode->i_private); + return NULL; +} + +const struct inode_operations debugfs_link_operations = { + .readlink = generic_readlink, + .follow_link = debugfs_follow_link, +}; + static void debugfs_u8_set(void *data, u64 val) { *(u8 *)data = val; diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c index c692487346ea..9c51a9f630a1 100644 --- a/fs/debugfs/inode.c +++ b/fs/debugfs/inode.c @@ -25,11 +25,13 @@ #include <linux/namei.h> #include <linux/debugfs.h> #include <linux/fsnotify.h> +#include <linux/string.h> #define DEBUGFS_MAGIC 0x64626720 /* declared over in file.c */ extern struct file_operations debugfs_file_operations; +extern struct inode_operations debugfs_link_operations; static struct vfsmount *debugfs_mount; static int debugfs_mount_count; @@ -51,6 +53,9 @@ static struct inode *debugfs_get_inode(struct super_block *sb, int mode, dev_t d case S_IFREG: inode->i_fop = &debugfs_file_operations; break; + case S_IFLNK: + inode->i_op = &debugfs_link_operations; + break; case S_IFDIR: inode->i_op = &simple_dir_inode_operations; inode->i_fop = &simple_dir_operations; @@ -96,6 +101,12 @@ static int debugfs_mkdir(struct inode *dir, struct dentry *dentry, int mode) return res; } +static int debugfs_link(struct inode *dir, struct dentry *dentry, int mode) +{ + mode = (mode & S_IALLUGO) | S_IFLNK; + return debugfs_mknod(dir, dentry, mode, 0); +} + static int debugfs_create(struct inode *dir, struct dentry *dentry, int mode) { int res; @@ -158,10 +169,17 @@ static int debugfs_create_by_name(const char *name, mode_t mode, mutex_lock(&parent->d_inode->i_mutex); *dentry = lookup_one_len(name, parent, strlen(name)); if (!IS_ERR(*dentry)) { - if ((mode & S_IFMT) == S_IFDIR) + switch (mode & S_IFMT) { + case S_IFDIR: error = debugfs_mkdir(parent->d_inode, *dentry, mode); - else + break; + case S_IFLNK: + error = debugfs_link(parent->d_inode, *dentry, mode); + break; + default: error = debugfs_create(parent->d_inode, *dentry, mode); + break; + } dput(*dentry); } else error = PTR_ERR(*dentry); @@ -259,6 +277,49 @@ struct dentry *debugfs_create_dir(const char *name, struct dentry *parent) EXPORT_SYMBOL_GPL(debugfs_create_dir); /** + * debugfs_create_symlink- create a symbolic link in the debugfs filesystem + * @name: a pointer to a string containing the name of the symbolic link to + * create. + * @parent: a pointer to the parent dentry for this symbolic link. This + * should be a directory dentry if set. If this paramater is NULL, + * then the symbolic link will be created in the root of the debugfs + * filesystem. + * @target: a pointer to a string containing the path to the target of the + * symbolic link. + * + * This function creates a symbolic link with the given name in debugfs that + * links to the given target path. + * + * This function will return a pointer to a dentry if it succeeds. This + * pointer must be passed to the debugfs_remove() function when the symbolic + * link is to be removed (no automatic cleanup happens if your module is + * unloaded, you are responsible here.) If an error occurs, %NULL will be + * returned. + * + * If debugfs is not enabled in the kernel, the value -%ENODEV will be + * returned. It is not wise to check for this value, but rather, check for + * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling + * code. + */ +struct dentry *debugfs_create_symlink(const char *name, struct dentry *parent, + const char *target) +{ + struct dentry *result; + char *link; + + link = kstrdup(target, GFP_KERNEL); + if (!link) + return NULL; + + result = debugfs_create_file(name, S_IFLNK | S_IRWXUGO, parent, link, + NULL); + if (!result) + kfree(link); + return result; +} +EXPORT_SYMBOL_GPL(debugfs_create_symlink); + +/** * debugfs_remove - removes a file or directory from the debugfs filesystem * @dentry: a pointer to a the dentry of the file or directory to be * removed. @@ -287,15 +348,22 @@ void debugfs_remove(struct dentry *dentry) if (debugfs_positive(dentry)) { if (dentry->d_inode) { dget(dentry); - if (S_ISDIR(dentry->d_inode->i_mode)) { + switch (dentry->d_inode->i_mode & S_IFMT) { + case S_IFDIR: ret = simple_rmdir(parent->d_inode, dentry); if (ret) printk(KERN_ERR "DebugFS rmdir on %s failed : " "directory not empty.\n", dentry->d_name.name); - } else + break; + case S_IFLNK: + kfree(dentry->d_inode->i_private); + /* fall through */ + default: simple_unlink(parent->d_inode, dentry); + break; + } if (!ret) d_delete(dentry); dput(dentry); diff --git a/include/linux/debugfs.h b/include/linux/debugfs.h index 047567d34ca7..9fa0983d1aa8 100644 --- a/include/linux/debugfs.h +++ b/include/linux/debugfs.h @@ -33,6 +33,9 @@ struct dentry *debugfs_create_file(const char *name, mode_t mode, struct dentry *debugfs_create_dir(const char *name, struct dentry *parent); +struct dentry *debugfs_create_symlink(const char *name, struct dentry *parent, + const char *dest); + void debugfs_remove(struct dentry *dentry); struct dentry *debugfs_create_u8(const char *name, mode_t mode, @@ -70,6 +73,13 @@ static inline struct dentry *debugfs_create_dir(const char *name, return ERR_PTR(-ENODEV); } +static inline struct dentry *debugfs_create_symlink(const char *name, + struct dentry *parent, + const char *dest) +{ + return ERR_PTR(-ENODEV); +} + static inline void debugfs_remove(struct dentry *dentry) { } |
