/* * kdatasize.c -- print the size of common data items from kernel space * This runs with any Linux kernel (not any Unix, because of <linux/types.h>) * * Copyright (C) 2001 Alessandro Rubini and Jonathan Corbet * Copyright (C) 2001 O'Reilly & Associates * * The source code in this file can be freely used, adapted, * and redistributed in source or binary form, so long as an * acknowledgment appears in derived source files.  The citation * should list that the code comes from the book "Linux Device * Drivers" by Alessandro Rubini and Jonathan Corbet, published * by O'Reilly & Associates.   No warranty is attached; * we cannot take responsibility for errors or fitness for use. */#include <linux/config.h>#include <linux/module.h>#include <linux/kernel.h>#include <linux/types.h>#include <linux/utsname.h>#include <linux/errno.h>/* * Define several data structures, all of them start with a lone char * in order to present an unaligned offset for the next field */struct c   {char c;  char      t;} c;struct s   {char c;  short     t;} s;struct i   {char c;  int       t;} i;struct l   {char c;  long      t;} l;struct ll  {char c;  long long t;} ll;struct p   {char c;  void *    t;} p;struct u1b {char c;  __u8      t;} u1b;struct u2b {char c;  __u16     t;} u2b;struct u4b {char c;  __u32     t;} u4b;struct u8b {char c;  __u64     t;} u8b;static void data_cleanup(void){	/* never called */}static int data_init(void){	/* print information and return an error */	printk("arch  Align:  char  short  int  long   ptr long-long "		" u8 u16 u32 u64\n");	printk("%-12s  %3i   %3i   %3i   %3i   %3i   %3i      "		"%3i %3i %3i %3i\n",		system_utsname.machine,		/* note that gcc can subtract void * values, but it's not ansi */		(int)((void *)(&c.t)   - (void *)&c),		(int)((void *)(&s.t)   - (void *)&s),		(int)((void *)(&i.t)   - (void *)&i),		(int)((void *)(&l.t)   - (void *)&l),		(int)((void *)(&p.t)   - (void *)&p),		(int)((void *)(&ll.t)  - (void *)&ll),		(int)((void *)(&u1b.t) - (void *)&u1b),		(int)((void *)(&u2b.t) - (void *)&u2b),		(int)((void *)(&u4b.t) - (void *)&u4b),		(int)((void *)(&u8b.t) - (void *)&u8b));	return -ENODEV;}module_init(data_init);module_exit(data_cleanup);MODULE_LICENSE("Dual BSD/GPL");