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kernel/configs.c 3.26 KB
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
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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>
f4b09ebc8   Adrian Bunk   update the email ...
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   * Copyright (C) 2002 Randy Dunlap <rdunlap@xenotime.net>
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
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   * 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 */