/* * proc sysctl test driver * * Copyright (C) 2017 Luis R. Rodriguez <mcgrof@kernel.org> * * This program is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License as published by the Free * Software Foundation; either version 2 of the License, or at your option any * later version; or, when distributed separately from the Linux kernel or * when incorporated into other software packages, subject to the following * license: * * This program is free software; you can redistribute it and/or modify it * under the terms of copyleft-next (version 0.3.1 or later) as published * at http://copyleft-next.org/. */ /* * This module provides an interface to the the proc sysctl interfaces.  This * driver requires CONFIG_PROC_SYSCTL. It will not normally be loaded by the * system unless explicitly requested by name. You can also build this driver * into your kernel. */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include <linux/init.h>#include <linux/list.h>#include <linux/module.h>#include <linux/printk.h>#include <linux/fs.h>#include <linux/miscdevice.h>#include <linux/slab.h>#include <linux/uaccess.h>#include <linux/async.h>#include <linux/delay.h>#include <linux/vmalloc.h> static int i_zero;static int i_one_hundred = 100; struct test_sysctl_data {	int int_0001;	int int_0002;	int int_0003[4]; 	unsigned int uint_0001; 	char string_0001[65]; #define SYSCTL_TEST_BITMAP_SIZE	65536	unsigned long *bitmap_0001;}; static struct test_sysctl_data test_data = {	.int_0001 = 60,	.int_0002 = 1, 	.int_0003[0] = 0,	.int_0003[1] = 1,	.int_0003[2] = 2,	.int_0003[3] = 3, 	.uint_0001 = 314, 	.string_0001 = "(none)",}; /* These are all under /proc/sys/debug/test_sysctl/ */static struct ctl_table test_table[] = {	{		.procname	= "int_0001",		.data		= &test_data.int_0001,		.maxlen		= sizeof(int),		.mode		= 0644,		.proc_handler	= proc_dointvec_minmax,		.extra1		= &i_zero,		.extra2         = &i_one_hundred,	},	{		.procname	= "int_0002",		.data		= &test_data.int_0002,		.maxlen		= sizeof(int),		.mode		= 0644,		.proc_handler	= proc_dointvec,	},	{		.procname	= "int_0003",		.data		= &test_data.int_0003,		.maxlen		= sizeof(test_data.int_0003),		.mode		= 0644,		.proc_handler	= proc_dointvec,	},	{		.procname	= "uint_0001",		.data		= &test_data.uint_0001,		.maxlen		= sizeof(unsigned int),		.mode		= 0644,		.proc_handler	= proc_douintvec,	},	{		.procname	= "string_0001",		.data		= &test_data.string_0001,		.maxlen		= sizeof(test_data.string_0001),		.mode		= 0644,		.proc_handler	= proc_dostring,	},	{		.procname	= "bitmap_0001",		.data		= &test_data.bitmap_0001,		.maxlen		= SYSCTL_TEST_BITMAP_SIZE,		.mode		= 0644,		.proc_handler	= proc_do_large_bitmap,	},	{ }}; static struct ctl_table test_sysctl_table[] = {	{		.procname	= "test_sysctl",		.maxlen		= 0,		.mode		= 0555,		.child		= test_table,	},	{ }}; static struct ctl_table test_sysctl_root_table[] = {	{		.procname	= "debug",		.maxlen		= 0,		.mode		= 0555,		.child		= test_sysctl_table,	},	{ }}; static struct ctl_table_header *test_sysctl_header; static int __init test_sysctl_init(void){	test_data.bitmap_0001 = kzalloc(SYSCTL_TEST_BITMAP_SIZE/8, GFP_KERNEL);	if (!test_data.bitmap_0001)		return -ENOMEM;	test_sysctl_header = register_sysctl_table(test_sysctl_root_table);	if (!test_sysctl_header) {		kfree(test_data.bitmap_0001);		return -ENOMEM;	}	return 0;}late_initcall(test_sysctl_init); static void __exit test_sysctl_exit(void){	kfree(test_data.bitmap_0001);	if (test_sysctl_header)		unregister_sysctl_table(test_sysctl_header);} module_exit(test_sysctl_exit); MODULE_AUTHOR("Luis R. Rodriguez <mcgrof@kernel.org>");MODULE_LICENSE("GPL");