1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * kernel/configs.c
4 * Echo the kernel .config file used to build the kernel
5 *
6 * Copyright (C) 2002 Khalid Aziz <khalid_aziz@hp.com>
7 * Copyright (C) 2002 Randy Dunlap <rdunlap@xenotime.net>
8 * Copyright (C) 2002 Al Stone <ahs3@fc.hp.com>
9 * Copyright (C) 2002 Hewlett-Packard Company
10 */
11
12 #include <linux/kernel.h>
13 #include <linux/module.h>
14 #include <linux/proc_fs.h>
15 #include <linux/seq_file.h>
16 #include <linux/init.h>
17 #include <linux/uaccess.h>
18
19 /*
20 * "IKCFG_ST" and "IKCFG_ED" are used to extract the config data from
21 * a binary kernel image or a module. See scripts/extract-ikconfig.
22 */
23 asm (
24 " .pushsection .rodata, \"a\" \n"
25 " .ascii \"IKCFG_ST\" \n"
26 " .global kernel_config_data \n"
27 "kernel_config_data: \n"
28 " .incbin \"kernel/config_data.gz\" \n"
29 " .global kernel_config_data_end \n"
30 "kernel_config_data_end: \n"
31 " .ascii \"IKCFG_ED\" \n"
32 " .popsection \n"
33 );
34
35 #ifdef CONFIG_IKCONFIG_PROC
36
37 extern char kernel_config_data;
38 extern char kernel_config_data_end;
39
40 static ssize_t
41 ikconfig_read_current(struct file *file, char __user *buf,
42 size_t len, loff_t * offset)
43 {
44 return simple_read_from_buffer(buf, len, offset,
45 &kernel_config_data,
46 &kernel_config_data_end -
47 &kernel_config_data);
48 }
49
50 static const struct proc_ops config_gz_proc_ops = {
51 .proc_read = ikconfig_read_current,
52 .proc_lseek = default_llseek,
53 };
54
55 static int __init ikconfig_init(void)
56 {
57 struct proc_dir_entry *entry;
58
59 /* create the current config file */
60 entry = proc_create("config.gz", S_IFREG | S_IRUGO, NULL,
61 &config_gz_proc_ops);
62 if (!entry)
63 return -ENOMEM;
64
65 proc_set_size(entry, &kernel_config_data_end - &kernel_config_data);
66
67 return 0;
68 }
69
70 static void __exit ikconfig_cleanup(void)
71 {
72 remove_proc_entry("config.gz", NULL);
73 }
74
75 module_init(ikconfig_init);
76 module_exit(ikconfig_cleanup);
77
78 #endif /* CONFIG_IKCONFIG_PROC */
79
80 MODULE_LICENSE("GPL");
81 MODULE_AUTHOR("Randy Dunlap");
82 MODULE_DESCRIPTION("Echo the kernel .config file used to build the kernel");
83
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