LXR linux/kernel/configs.c

   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 */
  23asm (
  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
  37extern char kernel_config_data;
  38extern char kernel_config_data_end;
  39
  40static ssize_t
  41ikconfig_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
  50static const struct file_operations ikconfig_file_ops = {
  51        .owner = THIS_MODULE,
  52        .read = ikconfig_read_current,
  53        .llseek = default_llseek,
  54};
  55
  56static 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
  71static void __exit ikconfig_cleanup(void)
  72{
  73        remove_proc_entry("config.gz", NULL);
  74}
  75
  76module_init(ikconfig_init);
  77module_exit(ikconfig_cleanup);
  78
  79#endif /* CONFIG_IKCONFIG_PROC */
  80
  81MODULE_LICENSE("GPL");
  82MODULE_AUTHOR("Randy Dunlap");
  83MODULE_DESCRIPTION("Echo the kernel .config file used to build the kernel");
  84