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 file_operations ikconfig_file_ops = { 51 .owner = THIS_MODULE, 52 .read = ikconfig_read_current, 53 .llseek = default_llseek, 54 }; 55 56 static int __init ikconfig_init(void) 57 { 58 struct proc_dir_entry *entry; 59 60 /* create the current config file */ 61 entry = proc_create("config.gz", S_IFREG | S_IRUGO, NULL, 62 &ikconfig_file_ops); 63 if (!entry) 64 return -ENOMEM; 65 66 proc_set_size(entry, &kernel_config_data_end - &kernel_config_data); 67 68 return 0; 69 } 70 71 static void __exit ikconfig_cleanup(void) 72 { 73 remove_proc_entry("config.gz", NULL); 74 } 75 76 module_init(ikconfig_init); 77 module_exit(ikconfig_cleanup); 78 79 #endif /* CONFIG_IKCONFIG_PROC */ 80 81 MODULE_LICENSE("GPL"); 82 MODULE_AUTHOR("Randy Dunlap"); 83 MODULE_DESCRIPTION("Echo the kernel .config file used to build the kernel"); 84