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 #define SYSCTL_TEST_BITMAP_SIZE 65536 52 unsigned long *bitmap_0001; 53 }; 54 55 static struct test_sysctl_data test_data = { 56 .int_0001 = 60, 57 .int_0002 = 1, 58 59 .int_0003[0] = 0, 60 .int_0003[1] = 1, 61 .int_0003[2] = 2, 62 .int_0003[3] = 3, 63 64 .uint_0001 = 314, 65 66 .string_0001 = "(none)", 67 }; 68 69 /* These are all under /proc/sys/debug/test_sysctl/ */ 70 static struct ctl_table test_table[] = { 71 { 72 .procname = "int_0001", 73 .data = &test_data.int_0001, 74 .maxlen = sizeof(int), 75 .mode = 0644, 76 .proc_handler = proc_dointvec_minmax, 77 .extra1 = &i_zero, 78 .extra2 = &i_one_hundred, 79 }, 80 { 81 .procname = "int_0002", 82 .data = &test_data.int_0002, 83 .maxlen = sizeof(int), 84 .mode = 0644, 85 .proc_handler = proc_dointvec, 86 }, 87 { 88 .procname = "int_0003", 89 .data = &test_data.int_0003, 90 .maxlen = sizeof(test_data.int_0003), 91 .mode = 0644, 92 .proc_handler = proc_dointvec, 93 }, 94 { 95 .procname = "uint_0001", 96 .data = &test_data.uint_0001, 97 .maxlen = sizeof(unsigned int), 98 .mode = 0644, 99 .proc_handler = proc_douintvec, 100 }, 101 { 102 .procname = "string_0001", 103 .data = &test_data.string_0001, 104 .maxlen = sizeof(test_data.string_0001), 105 .mode = 0644, 106 .proc_handler = proc_dostring, 107 }, 108 { 109 .procname = "bitmap_0001", 110 .data = &test_data.bitmap_0001, 111 .maxlen = SYSCTL_TEST_BITMAP_SIZE, 112 .mode = 0644, 113 .proc_handler = proc_do_large_bitmap, 114 }, 115 { } 116 }; 117 118 static struct ctl_table test_sysctl_table[] = { 119 { 120 .procname = "test_sysctl", 121 .maxlen = 0, 122 .mode = 0555, 123 .child = test_table, 124 }, 125 { } 126 }; 127 128 static struct ctl_table test_sysctl_root_table[] = { 129 { 130 .procname = "debug", 131 .maxlen = 0, 132 .mode = 0555, 133 .child = test_sysctl_table, 134 }, 135 { } 136 }; 137 138 static struct ctl_table_header *test_sysctl_header; 139 140 static int __init test_sysctl_init(void) 141 { 142 test_data.bitmap_0001 = kzalloc(SYSCTL_TEST_BITMAP_SIZE/8, GFP_KERNEL); 143 if (!test_data.bitmap_0001) 144 return -ENOMEM; 145 test_sysctl_header = register_sysctl_table(test_sysctl_root_table); 146 if (!test_sysctl_header) { 147 kfree(test_data.bitmap_0001); 148 return -ENOMEM; 149 } 150 return 0; 151 } 152 late_initcall(test_sysctl_init); 153 154 static void __exit test_sysctl_exit(void) 155 { 156 kfree(test_data.bitmap_0001); 157 if (test_sysctl_header) 158 unregister_sysctl_table(test_sysctl_header); 159 } 160 161 module_exit(test_sysctl_exit); 162 163 MODULE_AUTHOR("Luis R. Rodriguez <mcgrof@kernel.org>"); 164 MODULE_LICENSE("GPL"); 165