/* * file.c - part of debugfs, a tiny little debug file system * * Copyright (C) 2004 Greg Kroah-Hartman <greg@kroah.com> * Copyright (C) 2004 IBM Inc. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License version * 2 as published by the Free Software Foundation. * * debugfs is for people to use instead of /proc or /sys. * See Documentation/DocBook/kernel-api for more details. * */ #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, size_t count, loff_t *ppos) { return 0; } static ssize_t default_write_file(struct file *file, const char __user *buf, size_t count, loff_t *ppos) { return count; } static int default_open(struct inode *inode, struct file *file) { if (inode->i_private) file->private_data = inode->i_private; return 0; } const struct file_operations debugfs_file_operations = { .read = default_read_file, .write = default_write_file, .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; } static u64 debugfs_u8_get(void *data) { return *(u8 *)data; } DEFINE_SIMPLE_ATTRIBUTE(fops_u8, debugfs_u8_get, debugfs_u8_set, "%llu\n"); /** * debugfs_create_u8 - create a debugfs file that is used to read and write an unsigned 8-bit value * @name: a pointer to a string containing the name of the file to create. * @mode: the permission that the file should have * @parent: a pointer to the parent dentry for this file. This should be a * directory dentry if set. If this parameter is %NULL, then the * file will be created in the root of the debugfs filesystem. * @value: a pointer to the variable that the file should read to and write * from. * * This function creates a file in debugfs with the given name that * contains the value of the variable @value. If the @mode variable is so * set, it can be read from, and written to. * * This function will return a pointer to a dentry if it succeeds. This * pointer must be passed to the debugfs_remove() function when the file 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_u8(const char *name, mode_t mode, struct dentry *parent, u8 *value) { return debugfs_create_file(name, mode, parent, value, &fops_u8); } EXPORT_SYMBOL_GPL(debugfs_create_u8); static void debugfs_u16_set(void *data, u64 val) { *(u16 *)data = val; } static u64 debugfs_u16_get(void *data) { return *(u16 *)data; } DEFINE_SIMPLE_ATTRIBUTE(fops_u16, debugfs_u16_get, debugfs_u16_set, "%llu\n"); /** * debugfs_create_u16 - create a debugfs file that is used to read and write an unsigned 16-bit value * @name: a pointer to a string containing the name of the file to create. * @mode: the permission that the file should have * @parent: a pointer to the parent dentry for this file. This should be a * directory dentry if set. If this parameter is %NULL, then the * file will be created in the root of the debugfs filesystem. * @value: a pointer to the variable that the file should read to and write * from. * * This function creates a file in debugfs with the given name that * contains the value of the variable @value. If the @mode variable is so * set, it can be read from, and written to. * * This function will return a pointer to a dentry if it succeeds. This * pointer must be passed to the debugfs_remove() function when the file 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_u16(const char *name, mode_t mode, struct dentry *parent, u16 *value) { return debugfs_create_file(name, mode, parent, value, &fops_u16); } EXPORT_SYMBOL_GPL(debugfs_create_u16); static void debugfs_u32_set(void *data, u64 val) { *(u32 *)data = val; } static u64 debugfs_u32_get(void *data) { return *(u32 *)data; } DEFINE_SIMPLE_ATTRIBUTE(fops_u32, debugfs_u32_get, debugfs_u32_set, "%llu\n"); /** * debugfs_create_u32 - create a debugfs file that is used to read and write an unsigned 32-bit value * @name: a pointer to a string containing the name of the file to create. * @mode: the permission that the file should have * @parent: a pointer to the parent dentry for this file. This should be a * directory dentry if set. If this parameter is %NULL, then the * file will be created in the root of the debugfs filesystem. * @value: a pointer to the variable that the file should read to and write * from. * * This function creates a file in debugfs with the given name that * contains the value of the variable @value. If the @mode variable is so * set, it can be read from, and written to. * * This function will return a pointer to a dentry if it succeeds. This * pointer must be passed to the debugfs_remove() function when the file 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_u32(const char *name, mode_t mode, struct dentry *parent, u32 *value) { return debugfs_create_file(name, mode, parent, value, &fops_u32); } EXPORT_SYMBOL_GPL(debugfs_create_u32); static void debugfs_u64_set(void *data, u64 val) { *(u64 *)data = val; } static u64 debugfs_u64_get(void *data) { return *(u64 *)data; } DEFINE_SIMPLE_ATTRIBUTE(fops_u64, debugfs_u64_get, debugfs_u64_set, "%llu\n"); /** * debugfs_create_u64 - create a debugfs file that is used to read and write an unsigned 64-bit value * @name: a pointer to a string containing the name of the file to create. * @mode: the permission that the file should have * @parent: a pointer to the parent dentry for this file. This should be a * directory dentry if set. If this parameter is %NULL, then the * file will be created in the root of the debugfs filesystem. * @value: a pointer to the variable that the file should read to and write * from. * * This function creates a file in debugfs with the given name that * contains the value of the variable @value. If the @mode variable is so * set, it can be read from, and written to. * * This function will return a pointer to a dentry if it succeeds. This * pointer must be passed to the debugfs_remove() function when the file 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_u64(const char *name, mode_t mode, struct dentry *parent, u64 *value) { return debugfs_create_file(name, mode, parent, value, &fops_u64); } EXPORT_SYMBOL_GPL(debugfs_create_u64); DEFINE_SIMPLE_ATTRIBUTE(fops_x8, debugfs_u8_get, debugfs_u8_set, "0x%02llx\n"); DEFINE_SIMPLE_ATTRIBUTE(fops_x16, debugfs_u16_get, debugfs_u16_set, "0x%04llx\n"); DEFINE_SIMPLE_ATTRIBUTE(fops_x32, debugfs_u32_get, debugfs_u32_set, "0x%08llx\n"); /* * debugfs_create_x{8,16,32} - create a debugfs file that is used to read and write an unsigned {8,16,32}-bit value * * These functions are exactly the same as the above functions (but use a hex * output for the decimal challenged). For details look at the above unsigned * decimal functions. */ /** * debugfs_create_x8 - create a debugfs file that is used to read and write an unsigned 8-bit value * @name: a pointer to a string containing the name of the file to create. * @mode: the permission that the file should have * @parent: a pointer to the parent dentry for this file. This should be a * directory dentry if set. If this parameter is %NULL, then the * file will be created in the root of the debugfs filesystem. * @value: a pointer to the variable that the file should read to and write * from. */ struct dentry *debugfs_create_x8(const char *name, mode_t mode, struct dentry *parent, u8 *value) { return debugfs_create_file(name, mode, parent, value, &fops_x8); } EXPORT_SYMBOL_GPL(debugfs_create_x8); /** * debugfs_create_x16 - create a debugfs file that is used to read and write an unsigned 16-bit value * @name: a pointer to a string containing the name of the file to create. * @mode: the permission that the file should have * @parent: a pointer to the parent dentry for this file. This should be a * directory dentry if set. If this parameter is %NULL, then the * file will be created in the root of the debugfs filesystem. * @value: a pointer to the variable that the file should read to and write * from. */ struct dentry *debugfs_create_x16(const char *name, mode_t mode, struct dentry *parent, u16 *value) { return debugfs_create_file(name, mode, parent, value, &fops_x16); } EXPORT_SYMBOL_GPL(debugfs_create_x16); /** * debugfs_create_x32 - create a debugfs file that is used to read and write an unsigned 32-bit value * @name: a pointer to a string containing the name of the file to create. * @mode: the permission that the file should have * @parent: a pointer to the parent dentry for this file. This should be a * directory dentry if set. If this parameter is %NULL, then the * file will be created in the root of the debugfs filesystem. * @value: a pointer to the variable that the file should read to and write * from. */ struct dentry *debugfs_create_x32(const char *name, mode_t mode, struct dentry *parent, u32 *value) { return debugfs_create_file(name, mode, parent, value, &fops_x32); } EXPORT_SYMBOL_GPL(debugfs_create_x32); static ssize_t read_file_bool(struct file *file, char __user *user_buf, size_t count, loff_t *ppos) { char buf[3]; u32 *val = file->private_data; if (*val) buf[0] = 'Y'; else buf[0] = 'N'; buf[1] = '\n'; buf[2] = 0x00; return simple_read_from_buffer(user_buf, count, ppos, buf, 2); } static ssize_t write_file_bool(struct file *file, const char __user *user_buf, size_t count, loff_t *ppos) { char buf[32]; int buf_size; u32 *val = file->private_data; buf_size = min(count, (sizeof(buf)-1)); if (copy_from_user(buf, user_buf, buf_size)) return -EFAULT; switch (buf[0]) { case 'y': case 'Y': case '1': *val = 1; break; case 'n': case 'N': case '0': *val = 0; break; } return count; } static const struct file_operations fops_bool = { .read = read_file_bool, .write = write_file_bool, .open = default_open, }; /** * debugfs_create_bool - create a debugfs file that is used to read and write a boolean value * @name: a pointer to a string containing the name of the file to create. * @mode: the permission that the file should have * @parent: a pointer to the parent dentry for this file. This should be a * directory dentry if set. If this parameter is %NULL, then the * file will be created in the root of the debugfs filesystem. * @value: a pointer to the variable that the file should read to and write * from. * * This function creates a file in debugfs with the given name that * contains the value of the variable @value. If the @mode variable is so * set, it can be read from, and written to. * * This function will return a pointer to a dentry if it succeeds. This * pointer must be passed to the debugfs_remove() function when the file 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_bool(const char *name, mode_t mode, struct dentry *parent, u32 *value) { return debugfs_create_file(name, mode, parent, value, &fops_bool); } EXPORT_SYMBOL_GPL(debugfs_create_bool); static ssize_t read_file_blob(struct file *file, char __user *user_buf, size_t count, loff_t *ppos) { struct debugfs_blob_wrapper *blob = file->private_data; return simple_read_from_buffer(user_buf, count, ppos, blob->data, blob->size); } static const struct file_operations fops_blob = { .read = read_file_blob, .open = default_open, }; /** * debugfs_create_blob - create a debugfs file that is used to read and write a binary blob * @name: a pointer to a string containing the name of the file to create. * @mode: the permission that the file should have * @parent: a pointer to the parent dentry for this file. This should be a * directory dentry if set. If this parameter is %NULL, then the * file will be created in the root of the debugfs filesystem. * @blob: a pointer to a struct debugfs_blob_wrapper which contains a pointer * to the blob data and the size of the data. * * This function creates a file in debugfs with the given name that exports * @blob->data as a binary blob. If the @mode variable is so set it can be * read from. Writing is not supported. * * This function will return a pointer to a dentry if it succeeds. This * pointer must be passed to the debugfs_remove() function when the file 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_blob(const char *name, mode_t mode, struct dentry *parent, struct debugfs_blob_wrapper *blob) { return debugfs_create_file(name, mode, parent, blob, &fops_blob); } EXPORT_SYMBOL_GPL(debugfs_create_blob);