diff options
Diffstat (limited to 'fs/debugfs/file.c')
| -rw-r--r-- | fs/debugfs/file.c | 262 |
1 files changed, 262 insertions, 0 deletions
diff --git a/fs/debugfs/file.c b/fs/debugfs/file.c new file mode 100644 index 000000000000..548556ff2506 --- /dev/null +++ b/fs/debugfs/file.c @@ -0,0 +1,262 @@ +/* + * 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); + |