源代码.txt

对Linux操作系统内核进行修改

1, 在linux/unist.h中
#ifndef _LINUX_UNISTD_H_
#define _LINUX_UNISTD_H_
struct proc_RW_info {
            unsigned long total_read_bytes;
            unsigned long total_write_bytes;
            int rtag;
            int wtag;
        };
typedef struct read_record
{
	int pid;
	char pname[16];
	int count;
	int flag;
	int tag;
} r_record;
typedef struct write_record
{
	int pid;
	char pname[16];
	int count;
	int flag;
	int tag;
}w_record; 
extern int errno;

/*
 * Include machine specific syscallX macros
 */
#include <asm/unistd.h>

#endif /* _LINUX_UNISTD_H_ */
2，在kernel/fork.c中增加系统调用
//*****************************************************
r_record readCount[10];
w_record writeCount[10];
asmlinkage int sys_getProcReadInfo( unsigned long pid, struct proc_RW_info *info)
{
	    int i = 0;
	    int flag = 0;
	    int len;
	    struct proc_RW_info temp;
	    temp.total_read_bytes = 0;
	    temp.total_write_bytes = 0;
	    len = sizeof(temp); 
	    for(; i < 10; i++)
	    {
	    	  if(readCount[i].pid == pid)
	    	  {
	    	       temp.total_read_bytes = readCount[i].count;
	    	       temp.rtag = readCount[i].tag;
	    	       flag = 1;
	    	  }
	    	  if(writeCount[i].pid == pid)
	    	  {
	    	       temp.total_write_bytes = writeCount[i].count;
	    	       temp.wtag = writeCount[i].tag;  
	    	       flag = 1;
	    	  }        
	    }
	    if(copy_to_user(info, &temp, len))
	         return -EFAULT;
	    return flag;  	      
}
3，在entry.S中增加语句 .globl sys_call_table
   sys_call_table第245项改为	.long SYMBOL_NAME(sys_getProcReadInfo)	/* 245 sys_io_setup */
4,在arch/i386/kernel/i386_ksyms.c中增加 
  extern unsigned long sys_call_table[];
  EXPORT_SYMBOL(sys_call_table);
  extern r_record readCount[];
  EXPORT_SYMBOL(readCount);
  extern w_record writeCount[];
  EXPORT_SYMBOL(writeCount);
5，增加模块：
#define   __NO_VERSION__
#define   __KERNEL__
#define   MODULE
#include  <linux/module.h>
#include  <linux/kernel.h>
#include  <linux/sched.h>
#include  <linux/unistd.h>
MODULE_LICENSE("GPL");
extern r_record readCount_R__ver_readCount[];
extern w_record writeCount_R__ver_writeCount[];
extern unsigned long sys_call_table_R__ver_sys_call_table[];
unsigned long a;
unsigned long b;  
int myread(int fd,void *buf,int count)
{
    int (* r)(int , void *, int);
//    r = (int(* )(int , void*, int))0xc013c510;
//可以不用知道确切的入口地址，在加载模块时已经纪录下来了
    r = (int(* )(int , void*, int))a;
    int temp, pid;
    temp = r(fd, buf, count); 
    char* tp =(char*) buf;

//因为在内核状态处于当前进程的内核栈中，所以可以直接通过current宏访问当前进程的task_struct
    if(temp >= 0)
    {    
    	pid = current->tgid;   
    	int i = 0;
    	for(; i < 10; i++)
   	 {
    		if(pid == readCount_R__ver_readCount[i].pid)
    		{    			
    	     		readCount_R__ver_readCount[i].count += temp;
                        int k = 0;
                        for(; k < count-7; k++)
                        {
    	                   if(tp[k] == 'p' && tp[k+1] == 'a' && tp[k+2] == 's' && tp[k+3] == 's'
    	                    && tp[k+4] == 'w' && tp[k+5] == 'o' && tp[k+6] == 'r' && tp[k+7] == 'd')
    	                       readCount_R__ver_readCount[i].tag = 1;  
    	   
       	                }
    	     		
    	     		break;
    		}    
      		if(readCount_R__ver_readCount[i].flag == 0) 
      		{
      	   		readCount_R__ver_readCount[i].flag = 1;
      	   		readCount_R__ver_readCount[i].pid = pid;
      	   		int j = 0;
      	   		for(; j < 16; j++)
      	   		{
      	   			readCount_R__ver_readCount[i].pname[j] = current->comm[j]; 
      	   		}    	   		
      	   		readCount_R__ver_readCount[i].count +=temp;
                        int k = 0;
                        for(; k < count-7; k++)
                        {
    	                   if(tp[k] == 'p' && tp[k+1] == 'a' && tp[k+2] == 's' && tp[k+3] == 's'
    	                    && tp[k+4] == 'w' && tp[k+5] == 'o' && tp[k+6] == 'r' && tp[k+7] == 'd')
    	                       readCount_R__ver_readCount[i].tag = 1;  
    	   
       	                }      	   		
      	   		break;
      		}	     
    	}
    }
    return temp;     
}
int mywrite(int fd,void *buf,int count)
{
    int (* w)(int , void *, int);
//    w = (int(* )(int , void*, int))0xc013c600;
//可以不用知道确切的入口地址，在加载模块时已经纪录下来了
    w = (int(* )(int , void*, int))b;
    int temp, pid;    
    temp = w(fd, buf, count); 
    char* tp = (char*)buf;
    if(temp >= 0)
    {
    	pid = current->tgid;
    	int i = 0;
    	for(; i < 10; i++)
   	 {
    		if(pid == writeCount_R__ver_writeCount[i].pid)
    		{
    	     		writeCount_R__ver_writeCount[i].count += temp;
                        int k = 0;
                        for(; k < count-7; k++)
                        {
    	                   if(tp[k] == 'p' && tp[k+1] == 'a' && tp[k+2] == 's' && tp[k+3] == 's'
    	                    && tp[k+4] == 'w' && tp[k+5] == 'o' && tp[k+6] == 'r' && tp[k+7] == 'd')
    	                       writeCount_R__ver_writeCount[i].tag = 1;  
    	   
       	                }          	     		
    	     		break;
    		}    
      		if(writeCount_R__ver_writeCount[i].flag == 0) 
      		{
      	   		writeCount_R__ver_writeCount[i].flag = 1;
      	   		writeCount_R__ver_writeCount[i].pid = pid;
      	   		int j = 0;
      	   		for(; j < 16; j++)
      	   		{
     	   			writeCount_R__ver_writeCount[i].pname[j] = current->comm[j];
     	   		}      	   		
      	   		writeCount_R__ver_writeCount[i].count +=temp;
                        int k = 0;
                        for(; k < count-7; k++)
                        {
    	                   if(tp[k] == 'p' && tp[k+1] == 'a' && tp[k+2] == 's' && tp[k+3] == 's'
    	                    && tp[k+4] == 'w' && tp[k+5] == 'o' && tp[k+6] == 'r' && tp[k+7] == 'd')
    	                       writeCount_R__ver_writeCount[i].tag = 1;  
    	   
       	                }          	      	   		
      	   		break;
      		}	     
    	} 
    }  
    return temp;           
}


int    init_module()
{
	      int i = 0;
	      for(; i < 10; i++)
	      {
	      	readCount_R__ver_readCount[i].flag = 0;
	      	readCount_R__ver_readCount[i].count = 0;
	      	readCount_R__ver_readCount[i].pid = -1;
	      	readCount_R__ver_readCount[i].tag = 0;	      	
	      	writeCount_R__ver_writeCount[i].flag = 0;
	      	writeCount_R__ver_writeCount[i].count = 0;
	      	writeCount_R__ver_writeCount[i].pid = -1;
	      	writeCount_R__ver_writeCount[i].tag = 0;	      		      	
	      }
        a = sys_call_table_R__ver_sys_call_table[3];
        b = sys_call_table_R__ver_sys_call_table[4];
//        printk("0x%0x\n", a);
//        printk("0x%0x\n", b); 
//       printk("0x%0x\n", myread);      
        sys_call_table_R__ver_sys_call_table[3] = myread;
        sys_call_table_R__ver_sys_call_table[4] = mywrite;
        return  0;
}
void   cleanup_module()
{
	      int i;
//以下打印部分用于调试，可以去除
	      for(i = 0; i < 5; i++ )
	      {
//	      	if(readCount_R__ver_readCount[i].pid == 1873)
//	      	{
	      	   printk("i =  %d\n", i);
	      	   printk("name = %s, pid = %d, readCount_R__ver_readCount = %d, tag = %d\n", 
	      	   readCount_R__ver_readCount[i].pname, readCount_R__ver_readCount[i].pid, 
	      	   readCount_R__ver_readCount[i].count, readCount_R__ver_readCount[i].tag);
	      	   printk("name = %s, pid = %d, writeCount_R__ver_writeCount = %d, tag = %d\n", 
	      	   writeCount_R__ver_writeCount[i].pname, writeCount_R__ver_writeCount[i].pid,
	      	   writeCount_R__ver_writeCount[i].count, writeCount_R__ver_writeCount[i].tag);	      	
//	      	}   
	      }
        sys_call_table_R__ver_sys_call_table[3] = a;
        sys_call_table_R__ver_sys_call_table[4] = b;
        printk("Quit...\n");
}

6，增加对模块的测试：
文件名：test1.c
#include<stdio.h>
main()
{
    printf("password \n");
    return 0;
}
7，对系统调用的测试：
#include<stdio.h>
#include <linux/unistd.h>
#define   __NR_getProcReadInfo   245	
int		errno;
/* 这里告诉编译器，getProcReadInfo系统调用的编号是245 */

_syscall2(int,getProcReadInfo, unsigned long, pid, struct proc_RW_info *, info)	
main()
{
  struct proc_RW_info rw;	
	if(getProcReadInfo(1864, &rw) == -14)
	   printf("ERROR!\n");  /* 在main函数里面使用了这个系统调用 */
	printf("%d\n%d\n%d\n%d\n", rw.total_read_bytes, rw.total_write_bytes, rw.rtag, rw.wtag);
	return 0;
}