configs.c 3.2 KB

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  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. #include <linux/kernel.h>
  26. #include <linux/module.h>
  27. #include <linux/proc_fs.h>
  28. #include <linux/seq_file.h>
  29. #include <linux/init.h>
  30. #include <asm/uaccess.h>
  31. /**************************************************/
  32. /* the actual current config file */
  33. /*
  34. * Define kernel_config_data and kernel_config_data_size, which contains the
  35. * wrapped and compressed configuration file. The file is first compressed
  36. * with gzip and then bounded by two eight byte magic numbers to allow
  37. * extraction from a binary kernel image:
  38. *
  39. * IKCFG_ST
  40. * <image>
  41. * IKCFG_ED
  42. */
  43. #define MAGIC_START "IKCFG_ST"
  44. #define MAGIC_END "IKCFG_ED"
  45. #include "config_data.h"
  46. #define MAGIC_SIZE (sizeof(MAGIC_START) - 1)
  47. #define kernel_config_data_size \
  48. (sizeof(kernel_config_data) - 1 - MAGIC_SIZE * 2)
  49. #ifdef CONFIG_IKCONFIG_PROC
  50. /**************************************************/
  51. /* globals and useful constants */
  52. static ssize_t
  53. ikconfig_read_current(struct file *file, char __user *buf,
  54. size_t len, loff_t * offset)
  55. {
  56. loff_t pos = *offset;
  57. ssize_t count;
  58. if (pos >= kernel_config_data_size)
  59. return 0;
  60. count = min(len, (size_t)(kernel_config_data_size - pos));
  61. if (copy_to_user(buf, kernel_config_data + MAGIC_SIZE + pos, count))
  62. return -EFAULT;
  63. *offset += count;
  64. return count;
  65. }
  66. static const struct file_operations ikconfig_file_ops = {
  67. .owner = THIS_MODULE,
  68. .read = ikconfig_read_current,
  69. };
  70. /***************************************************/
  71. /* ikconfig_init: start up everything we need to */
  72. static int __init ikconfig_init(void)
  73. {
  74. struct proc_dir_entry *entry;
  75. /* create the current config file */
  76. entry = create_proc_entry("config.gz", S_IFREG | S_IRUGO,
  77. &proc_root);
  78. if (!entry)
  79. return -ENOMEM;
  80. entry->proc_fops = &ikconfig_file_ops;
  81. entry->size = kernel_config_data_size;
  82. return 0;
  83. }
  84. /***************************************************/
  85. /* ikconfig_cleanup: clean up our mess */
  86. static void __exit ikconfig_cleanup(void)
  87. {
  88. remove_proc_entry("config.gz", &proc_root);
  89. }
  90. module_init(ikconfig_init);
  91. module_exit(ikconfig_cleanup);
  92. MODULE_LICENSE("GPL");
  93. MODULE_AUTHOR("Randy Dunlap");
  94. MODULE_DESCRIPTION("Echo the kernel .config file used to build the kernel");
  95. #endif /* CONFIG_IKCONFIG_PROC */