/* * Written by Der Herr Hofrat, der.herr@hofr.at * (C) 2002 FSMLabs * License: GPL Version 2 */#define __KERNEL_SYSCALLS__#include <linux/config.h>#include <linux/module.h>#include <linux/sched.h>#include <linux/unistd.h>#include <linux/kmod.h>#include <linux/errno.h>#include <linux/unistd.h>#include <linux/smp_lock.h>#include <asm/uaccess.h>static int errno;static char cmd_path[256] = "/bin/echo";static int exec_cmd(void * kthread_arg){	struct task_struct *curtask = current;	/* we set up a minimum environment but note that we still inherit	 * the environment of who ever launched insmod of this module !	 * sounds dangorous ? - it is !	 */	static char * envp[] = { "HOME=/root ", 		"TERM=linux ", 		"PATH=/bin", 		NULL };	char *argv[] = { 		cmd_path,		kthread_arg,		NULL };	int ret;	/* Give the kthread all effective privileges...scarry... */	curtask->euid = curtask->fsuid = 0;	curtask->egid = curtask->fsgid = 0;	cap_set_full(curtask->cap_effective);	/* Allow execve args to be in kernel space. */	set_fs(KERNEL_DS);	printk("calling execve for %s \n",cmd_path); 	ret = execve(cmd_path, argv, envp);	/* if we ever get here - execve failed */	printk(KERN_ERR "failed to exec %s, ret = %d\n", cmd_path,ret);	return -1;}int init_module(void){	pid_t pid;	char kthread_arg[]="Hello Kernel World !";	pid = kernel_thread(exec_cmd, (void*) kthread_arg, 0);	if (pid < 0) {		printk(KERN_ERR "fork failed, errno %d\n", -pid);		return pid;	}	printk("fork ok, pid %d\n",pid);	return 0;}void cleanup_module(void){	pid_t pid;	char kthread_arg[]="Good by crul World :)";	pid = kernel_thread(exec_cmd, (void*) kthread_arg, 0);	if (pid < 0) {		printk(KERN_ERR "fork failed, errno %d\n", -pid);	}	printk("fork ok, pid %d\n",pid);	printk("module exit\n");}