configs.c

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/*
 * kernel/configs.c
 * Echo the kernel .config file used to build the kernel
 *
 * Copyright (C) 2002 Khalid Aziz <[email protected]>
 * Copyright (C) 2002 Randy Dunlap <[email protected]>
 * Copyright (C) 2002 Al Stone <[email protected]>
 * 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/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

static ssize_t
ikconfig_read_current(struct file *file, char __user *buf,
              size_t len, loff_t * offset)
{
    return simple_read_from_buffer(buf, len, offset,
                       kernel_config_data + MAGIC_SIZE,
                       kernel_config_data_size);
}

static const struct file_operations ikconfig_file_ops = {
    .owner = THIS_MODULE,
    .read = ikconfig_read_current,
    .llseek = default_llseek,
};

static int __init ikconfig_init(void)
{
    struct proc_dir_entry *entry;

    /* create the current config file */
    entry = proc_create("config.gz", S_IFREG | S_IRUGO, NULL,
                &ikconfig_file_ops);
    if (!entry)
        return -ENOMEM;

    entry->size = kernel_config_data_size;

    return 0;
}

static void __exit ikconfig_cleanup(void)
{
    remove_proc_entry("config.gz", NULL);
}

module_init(ikconfig_init);
module_exit(ikconfig_cleanup);

#endif /* CONFIG_IKCONFIG_PROC */

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Randy Dunlap");
MODULE_DESCRIPTION("Echo the kernel .config file used to build the kernel");