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 <rddunlap@osdl.org> 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/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 61 static ssize_t 62 ikconfig_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 79 static 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 87 static 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 */ 105 106 static void __exit ikconfig_cleanup(void) 107 { 108 remove_proc_entry("config.gz", &proc_root); 109 } 110 111 module_init(ikconfig_init); 112 module_exit(ikconfig_cleanup); 113 114 MODULE_LICENSE("GPL"); 115 MODULE_AUTHOR("Randy Dunlap"); 116 MODULE_DESCRIPTION("Echo the kernel .config file used to build the kernel"); 117 118 #endif /* CONFIG_IKCONFIG_PROC */ 119