1 /* 2 * proc sysctl test driver 3 * 4 * Copyright (C) 2017 Luis R. Rodriguez <mcgrof@kernel.org> 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 int int_0002; 45 int int_0003[4]; 46 47 unsigned int uint_0001; 48 49 char string_0001[65]; 50 }; 51 52 static struct test_sysctl_data test_data = { 53 .int_0001 = 60, 54 .int_0002 = 1, 55 56 .int_0003[0] = 0, 57 .int_0003[1] = 1, 58 .int_0003[2] = 2, 59 .int_0003[3] = 3, 60 61 .uint_0001 = 314, 62 63 .string_0001 = "(none)", 64 }; 65 66 /* These are all under /proc/sys/debug/test_sysctl/ */ 67 static struct ctl_table test_table[] = { 68 { 69 .procname = "int_0001", 70 .data = &test_data.int_0001, 71 .maxlen = sizeof(int), 72 .mode = 0644, 73 .proc_handler = proc_dointvec_minmax, 74 .extra1 = &i_zero, 75 .extra2 = &i_one_hundred, 76 }, 77 { 78 .procname = "int_0002", 79 .data = &test_data.int_0002, 80 .maxlen = sizeof(int), 81 .mode = 0644, 82 .proc_handler = proc_dointvec, 83 }, 84 { 85 .procname = "int_0003", 86 .data = &test_data.int_0003, 87 .maxlen = sizeof(test_data.int_0003), 88 .mode = 0644, 89 .proc_handler = proc_dointvec, 90 }, 91 { 92 .procname = "uint_0001", 93 .data = &test_data.uint_0001, 94 .maxlen = sizeof(unsigned int), 95 .mode = 0644, 96 .proc_handler = proc_douintvec, 97 }, 98 { 99 .procname = "string_0001", 100 .data = &test_data.string_0001, 101 .maxlen = sizeof(test_data.string_0001), 102 .mode = 0644, 103 .proc_handler = proc_dostring, 104 }, 105 { } 106 }; 107 108 static struct ctl_table test_sysctl_table[] = { 109 { 110 .procname = "test_sysctl", 111 .maxlen = 0, 112 .mode = 0555, 113 .child = test_table, 114 }, 115 { } 116 }; 117 118 static struct ctl_table test_sysctl_root_table[] = { 119 { 120 .procname = "debug", 121 .maxlen = 0, 122 .mode = 0555, 123 .child = test_sysctl_table, 124 }, 125 { } 126 }; 127 128 static struct ctl_table_header *test_sysctl_header; 129 130 static int __init test_sysctl_init(void) 131 { 132 test_sysctl_header = register_sysctl_table(test_sysctl_root_table); 133 if (!test_sysctl_header) 134 return -ENOMEM; 135 return 0; 136 } 137 late_initcall(test_sysctl_init); 138 139 static void __exit test_sysctl_exit(void) 140 { 141 if (test_sysctl_header) 142 unregister_sysctl_table(test_sysctl_header); 143 } 144 145 module_exit(test_sysctl_exit); 146 147 MODULE_AUTHOR("Luis R. Rodriguez <mcgrof@kernel.org>"); 148 MODULE_LICENSE("GPL"); 149