/* * 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/config.h> #include <linux/module.h> #include <linux/fs.h> #include <linux/pagemap.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->u.generic_ip) file->private_data = inode->u.generic_ip; return 0; } struct file_operations debugfs_file_operations = { .read = default_read_file, .write = default_write_file, .open = default_open, }; #define simple_type(type, format, temptype, strtolfn) \ static ssize_t read_file_##type(struct file *file, char __user *user_buf, \ size_t count, loff_t *ppos) \ { \ char buf[32]; \ type *val = file->private_data; \ \ snprintf(buf, sizeof(buf), format "\n", *val); \ return simple_read_from_buffer(user_buf, count, ppos, buf, strlen(buf));\ } \ static ssize_t write_file_##type(struct file *file, const char __user *user_buf,\ size_t count, loff_t *ppos) \ { \ char *endp; \ char buf[32]; \ int buf_size; \ type *val = file->private_data; \ temptype tmp; \ \ memset(buf, 0x00, sizeof(buf)); \ buf_size = min(count, (sizeof(buf)-1)); \ if (copy_from_user(buf, user_buf, buf_size)) \ return -EFAULT; \ \ tmp = strtolfn(buf, &endp, 0); \ if ((endp == buf) || ((type)tmp != tmp)) \ return -EINVAL; \ *val = tmp; \ return count; \ } \ static struct file_operations fops_##type = { \ .read = read_file_##type, \ .write = write_file_##type, \ .open = default_open, \ }; simple_type(u8, "%c", unsigned long, simple_strtoul); simple_type(u16, "%hi", unsigned long, simple_strtoul); simple_type(u32, "%i", unsigned long, simple_strtoul); /** * debugfs_create_u8 - create a file in the debugfs filesystem that is used to read and write a 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 paramater 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); /** * debugfs_create_u16 - create a file in the debugfs filesystem that is used to read and write a 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 paramater 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); /** * debugfs_create_u32 - create a file in the debugfs filesystem that is used to read and write a 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 paramater 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 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 struct file_operations fops_bool = { .read = read_file_bool, .write = write_file_bool, .open = default_open, }; /** * debugfs_create_bool - create a file in the debugfs filesystem 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 paramater 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);