1 /* 2 * proc sysctl test driver 3 * 4 * Copyright (C) 2017 Luis R. Rodriguez <[email protected]> 5 * 6 * This program is free software; you can redistribute it and/or modify it 7 * under the terms of the GNU General Public License as published by the Free 8 * Software Foundation; either version 2 of the License, or at your option any 9 * later version; or, when distributed separately from the Linux kernel or 10 * when incorporated into other software packages, subject to the following 11 * license: 12 * 13 * This program is free software; you can redistribute it and/or modify it 14 * under the terms of copyleft-next (version 0.3.1 or later) as published 15 * at http://copyleft-next.org/. 16 */ 17 18 /* 19 * This module provides an interface to the the proc sysctl interfaces. This 20 * driver requires CONFIG_PROC_SYSCTL. It will not normally be loaded by the 21 * system unless explicitly requested by name. You can also build this driver 22 * into your kernel. 23 */ 24 25 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 26 27 #include <linux/init.h> 28 #include <linux/list.h> 29 #include <linux/module.h> 30 #include <linux/printk.h> 31 #include <linux/fs.h> 32 #include <linux/miscdevice.h> 33 #include <linux/slab.h> 34 #include <linux/uaccess.h> 35 #include <linux/async.h> 36 #include <linux/delay.h> 37 #include <linux/vmalloc.h> 38 39 static int i_zero; 40 static int i_one_hundred = 100; 41 42 struct test_sysctl_data { 43 int int_0001; 44 char string_0001[65]; 45 }; 46 47 static struct test_sysctl_data test_data = { 48 .int_0001 = 60, 49 .string_0001 = "(none)", 50 }; 51 52 /* These are all under /proc/sys/debug/test_sysctl/ */ 53 static struct ctl_table test_table[] = { 54 { 55 .procname = "int_0001", 56 .data = &test_data.int_0001, 57 .maxlen = sizeof(int), 58 .mode = 0644, 59 .proc_handler = proc_dointvec_minmax, 60 .extra1 = &i_zero, 61 .extra2 = &i_one_hundred, 62 }, 63 { 64 .procname = "string_0001", 65 .data = &test_data.string_0001, 66 .maxlen = sizeof(test_data.string_0001), 67 .mode = 0644, 68 .proc_handler = proc_dostring, 69 }, 70 { } 71 }; 72 73 static struct ctl_table test_sysctl_table[] = { 74 { 75 .procname = "test_sysctl", 76 .maxlen = 0, 77 .mode = 0555, 78 .child = test_table, 79 }, 80 { } 81 }; 82 83 static struct ctl_table test_sysctl_root_table[] = { 84 { 85 .procname = "debug", 86 .maxlen = 0, 87 .mode = 0555, 88 .child = test_sysctl_table, 89 }, 90 { } 91 }; 92 93 static struct ctl_table_header *test_sysctl_header; 94 95 static int __init test_sysctl_init(void) 96 { 97 test_sysctl_header = register_sysctl_table(test_sysctl_root_table); 98 if (!test_sysctl_header) 99 return -ENOMEM; 100 return 0; 101 } 102 late_initcall(test_sysctl_init); 103 104 static void __exit test_sysctl_exit(void) 105 { 106 if (test_sysctl_header) 107 unregister_sysctl_table(test_sysctl_header); 108 } 109 110 module_exit(test_sysctl_exit); 111 112 MODULE_AUTHOR("Luis R. Rodriguez <[email protected]>"); 113 MODULE_LICENSE("GPL"); 114