kernel/configs.c

   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 <linux/uaccess.h>
  32
  33 /*
  34  * "IKCFG_ST" and "IKCFG_ED" are used to extract the config data from
  35  * a binary kernel image or a module. See scripts/extract-ikconfig.
  36  */
  37 asm (
  38 "       .pushsection .rodata, \"a\"             \n"
  39 "       .ascii \"IKCFG_ST\"                     \n"
  40 "       .global kernel_config_data              \n"
  41 "kernel_config_data:                            \n"
  42 "       .incbin \"kernel/config_data.gz\"       \n"
  43 "       .global kernel_config_data_end          \n"
  44 "kernel_config_data_end:                        \n"
  45 "       .ascii \"IKCFG_ED\"                     \n"
  46 "       .popsection                             \n"
  47 );
  48
  49 #ifdef CONFIG_IKCONFIG_PROC
  50
  51 extern char kernel_config_data;
  52 extern char kernel_config_data_end;
  53
  54 static ssize_t
  55 ikconfig_read_current(struct file *file, char __user *buf,
  56                       size_t len, loff_t * offset)
  57 {
  58         return simple_read_from_buffer(buf, len, offset,
  59                                        &kernel_config_data,
  60                                        &kernel_config_data_end -
  61                                        &kernel_config_data);
  62 }
  63
  64 static const struct file_operations ikconfig_file_ops = {
  65         .owner = THIS_MODULE,
  66         .read = ikconfig_read_current,
  67         .llseek = default_llseek,
  68 };
  69
  70 static int __init ikconfig_init(void)
  71 {
  72         struct proc_dir_entry *entry;
  73
  74         /* create the current config file */
  75         entry = proc_create("config.gz", S_IFREG | S_IRUGO, NULL,
  76                             &ikconfig_file_ops);
  77         if (!entry)
  78                 return -ENOMEM;
  79
  80         proc_set_size(entry, &kernel_config_data_end - &kernel_config_data);
  81
  82         return 0;
  83 }
  84
  85 static void __exit ikconfig_cleanup(void)
  86 {
  87         remove_proc_entry("config.gz", NULL);
  88 }
  89
  90 module_init(ikconfig_init);
  91 module_exit(ikconfig_cleanup);
  92
  93 #endif /* CONFIG_IKCONFIG_PROC */
  94
  95 MODULE_LICENSE("GPL");
  96 MODULE_AUTHOR("Randy Dunlap");
  97 MODULE_DESCRIPTION("Echo the kernel .config file used to build the kernel");