blob: 009e1ebdcb88e57b62d64daafb4be1be9468a514 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * kernel/configs.c
3 * Echo the kernel .config file used to build the kernel
4 *
5 * Copyright (C) 2002 Khalid Aziz <khalid_aziz@hp.com>
Adrian Bunkf4b09eb2006-01-03 13:37:51 +01006 * Copyright (C) 2002 Randy Dunlap <rdunlap@xenotime.net>
Linus Torvalds1da177e2005-04-16 15:20:36 -07007 * Copyright (C) 2002 Al Stone <ahs3@fc.hp.com>
8 * Copyright (C) 2002 Hewlett-Packard Company
9 *
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License as published by
12 * the Free Software Foundation; either version 2 of the License, or (at
13 * your option) any later version.
14 *
15 * This program is distributed in the hope that it will be useful, but
16 * WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
18 * NON INFRINGEMENT. See the GNU General Public License for more
19 * details.
20 *
21 * You should have received a copy of the GNU General Public License
22 * along with this program; if not, write to the Free Software
23 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
24 */
25
26#include <linux/config.h>
27#include <linux/kernel.h>
28#include <linux/module.h>
29#include <linux/proc_fs.h>
30#include <linux/seq_file.h>
31#include <linux/init.h>
32#include <asm/uaccess.h>
33
34/**************************************************/
35/* the actual current config file */
36
37/*
38 * Define kernel_config_data and kernel_config_data_size, which contains the
39 * wrapped and compressed configuration file. The file is first compressed
40 * with gzip and then bounded by two eight byte magic numbers to allow
41 * extraction from a binary kernel image:
42 *
43 * IKCFG_ST
44 * <image>
45 * IKCFG_ED
46 */
47#define MAGIC_START "IKCFG_ST"
48#define MAGIC_END "IKCFG_ED"
49#include "config_data.h"
50
51
52#define MAGIC_SIZE (sizeof(MAGIC_START) - 1)
53#define kernel_config_data_size \
54 (sizeof(kernel_config_data) - 1 - MAGIC_SIZE * 2)
55
56#ifdef CONFIG_IKCONFIG_PROC
57
58/**************************************************/
59/* globals and useful constants */
60
61static ssize_t
62ikconfig_read_current(struct file *file, char __user *buf,
63 size_t len, loff_t * offset)
64{
65 loff_t pos = *offset;
66 ssize_t count;
67
68 if (pos >= kernel_config_data_size)
69 return 0;
70
71 count = min(len, (size_t)(kernel_config_data_size - pos));
72 if (copy_to_user(buf, kernel_config_data + MAGIC_SIZE + pos, count))
73 return -EFAULT;
74
75 *offset += count;
76 return count;
77}
78
79static struct file_operations ikconfig_file_ops = {
80 .owner = THIS_MODULE,
81 .read = ikconfig_read_current,
82};
83
84/***************************************************/
85/* ikconfig_init: start up everything we need to */
86
87static int __init ikconfig_init(void)
88{
89 struct proc_dir_entry *entry;
90
91 /* create the current config file */
92 entry = create_proc_entry("config.gz", S_IFREG | S_IRUGO,
93 &proc_root);
94 if (!entry)
95 return -ENOMEM;
96
97 entry->proc_fops = &ikconfig_file_ops;
98 entry->size = kernel_config_data_size;
99
100 return 0;
101}
102
103/***************************************************/
104/* ikconfig_cleanup: clean up our mess */
105
106static void __exit ikconfig_cleanup(void)
107{
108 remove_proc_entry("config.gz", &proc_root);
109}
110
111module_init(ikconfig_init);
112module_exit(ikconfig_cleanup);
113
114MODULE_LICENSE("GPL");
115MODULE_AUTHOR("Randy Dunlap");
116MODULE_DESCRIPTION("Echo the kernel .config file used to build the kernel");
117
118#endif /* CONFIG_IKCONFIG_PROC */