linux/kernel/configs.c

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/*
* kernel/configs.c
* Echo the kernel .config file used to build the kernel
*
* Copyright (C) 2002 Khalid Aziz <khalid_aziz@hp.com>
* Copyright (C) 2002 Randy Dunlap <rdunlap@xenotime.net>
* Copyright (C) 2002 Al Stone <ahs3@fc.hp.com>
* Copyright (C) 2002 Hewlett-Packard Company
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or (at
* your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
* NON INFRINGEMENT. See the GNU General Public License for more
* details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <linux/config.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/init.h>
#include <asm/uaccess.h>
/**************************************************/
/* the actual current config file */
/*
* Define kernel_config_data and kernel_config_data_size, which contains the
* wrapped and compressed configuration file. The file is first compressed
* with gzip and then bounded by two eight byte magic numbers to allow
* extraction from a binary kernel image:
*
* IKCFG_ST
* <image>
* IKCFG_ED
*/
#define MAGIC_START "IKCFG_ST"
#define MAGIC_END "IKCFG_ED"
#include "config_data.h"
#define MAGIC_SIZE (sizeof(MAGIC_START) - 1)
#define kernel_config_data_size \
(sizeof(kernel_config_data) - 1 - MAGIC_SIZE * 2)
#ifdef CONFIG_IKCONFIG_PROC
/**************************************************/
/* globals and useful constants */
static ssize_t
ikconfig_read_current(struct file *file, char __user *buf,
size_t len, loff_t * offset)
{
loff_t pos = *offset;
ssize_t count;
if (pos >= kernel_config_data_size)
return 0;
count = min(len, (size_t)(kernel_config_data_size - pos));
if (copy_to_user(buf, kernel_config_data + MAGIC_SIZE + pos, count))
return -EFAULT;
*offset += count;
return count;
}
static struct file_operations ikconfig_file_ops = {
.owner = THIS_MODULE,
.read = ikconfig_read_current,
};
/***************************************************/
/* ikconfig_init: start up everything we need to */
static int __init ikconfig_init(void)
{
struct proc_dir_entry *entry;
/* create the current config file */
entry = create_proc_entry("config.gz", S_IFREG | S_IRUGO,
&proc_root);
if (!entry)
return -ENOMEM;
entry->proc_fops = &ikconfig_file_ops;
entry->size = kernel_config_data_size;
return 0;
}
/***************************************************/
/* ikconfig_cleanup: clean up our mess */
static void __exit ikconfig_cleanup(void)
{
remove_proc_entry("config.gz", &proc_root);
}
module_init(ikconfig_init);
module_exit(ikconfig_cleanup);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Randy Dunlap");
MODULE_DESCRIPTION("Echo the kernel .config file used to build the kernel");
#endif /* CONFIG_IKCONFIG_PROC */