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1 /*
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>
6  * Copyright (C) 2002 Randy Dunlap <rdunlap@xenotime.net>
7  * 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/kernel.h>
27 #include <linux/module.h>
28 #include <linux/proc_fs.h>
29 #include <linux/seq_file.h>
30 #include <linux/init.h>
31 #include <asm/uaccess.h>
32 
33 /**************************************************/
34 /* the actual current config file                 */
35 
36 /*
37  * Define kernel_config_data and kernel_config_data_size, which contains the
38  * wrapped and compressed configuration file.  The file is first compressed
39  * with gzip and then bounded by two eight byte magic numbers to allow
40  * extraction from a binary kernel image:
41  *
42  *   IKCFG_ST
43  *   <image>
44  *   IKCFG_ED
45  */
46 #define MAGIC_START	"IKCFG_ST"
47 #define MAGIC_END	"IKCFG_ED"
48 #include "config_data.h"
49 
50 
51 #define MAGIC_SIZE (sizeof(MAGIC_START) - 1)
52 #define kernel_config_data_size \
53 	(sizeof(kernel_config_data) - 1 - MAGIC_SIZE * 2)
54 
55 #ifdef CONFIG_IKCONFIG_PROC
56 
57 static ssize_t
ikconfig_read_current(struct file * file,char __user * buf,size_t len,loff_t * offset)58 ikconfig_read_current(struct file *file, char __user *buf,
59 		      size_t len, loff_t * offset)
60 {
61 	return simple_read_from_buffer(buf, len, offset,
62 				       kernel_config_data + MAGIC_SIZE,
63 				       kernel_config_data_size);
64 }
65 
66 static const struct file_operations ikconfig_file_ops = {
67 	.owner = THIS_MODULE,
68 	.read = ikconfig_read_current,
69 	.llseek = default_llseek,
70 };
71 
ikconfig_init(void)72 static int __init ikconfig_init(void)
73 {
74 	struct proc_dir_entry *entry;
75 
76 	/* create the current config file */
77 	entry = proc_create("config.gz", S_IFREG | S_IRUGO, NULL,
78 			    &ikconfig_file_ops);
79 	if (!entry)
80 		return -ENOMEM;
81 
82 	proc_set_size(entry, kernel_config_data_size);
83 
84 	return 0;
85 }
86 
ikconfig_cleanup(void)87 static void __exit ikconfig_cleanup(void)
88 {
89 	remove_proc_entry("config.gz", NULL);
90 }
91 
92 module_init(ikconfig_init);
93 module_exit(ikconfig_cleanup);
94 
95 #endif /* CONFIG_IKCONFIG_PROC */
96 
97 MODULE_LICENSE("GPL");
98 MODULE_AUTHOR("Randy Dunlap");
99 MODULE_DESCRIPTION("Echo the kernel .config file used to build the kernel");
100