串口重定向

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 

extern int fd;
extern int fd5;
char g_buff[512];
int  g_nread = 0;

int set_option(int fd,int nSpeed, int nBits, char nEvent, int nStop)
{
    struct termios newtio,oldtio;
    if  ( tcgetattr( fd,&oldtio)  !=  0) 
    { 
        perror("SetupSerial 1");
        return -1;
    }
    bzero( &newtio, sizeof( newtio ) );
    newtio.c_cflag  |=  CLOCAL | CREAD; 
    newtio.c_cflag &= ~CSIZE; 

    switch( nBits )
    {
        case 7:
            newtio.c_cflag |= CS7;
            break;
        case 8:
            newtio.c_cflag |= CS8;
            break;
    }

    switch( nEvent )
    {
        case 'O':                     
            newtio.c_cflag |= PARENB;
            newtio.c_cflag |= PARODD;
            newtio.c_iflag |= (INPCK | ISTRIP);
            break;
        case 'E':                     
            newtio.c_iflag |= (INPCK | ISTRIP);
            newtio.c_cflag |= PARENB;
            newtio.c_cflag &= ~PARODD;
            break;
        case 'N':                    
            newtio.c_cflag &= ~PARENB;
            break;
    }

    switch( nSpeed )
    {
        case 2400:
            cfsetispeed(&newtio, B2400);
            cfsetospeed(&newtio, B2400);
            break;
        case 4800:
            cfsetispeed(&newtio, B4800);
            cfsetospeed(&newtio, B4800);
            break;
        case 9600:
            cfsetispeed(&newtio, B9600);
            cfsetospeed(&newtio, B9600);
            break;
        case 115200:
            cfsetispeed(&newtio, B115200);
            cfsetospeed(&newtio, B115200);
            break;
        default:
            cfsetispeed(&newtio, B9600);
            cfsetospeed(&newtio, B9600);
            break;
    }
    if( nStop == 1 )
    {
        newtio.c_cflag &=  ~CSTOPB;
    }
    else if ( nStop == 2 )
    {
        newtio.c_cflag |=  CSTOPB;
    }
    newtio.c_cc[VTIME]  = 0;
    newtio.c_cc[VMIN] = 0;
    tcflush(fd,TCIFLUSH);
    if((tcsetattr(fd,TCSANOW,&newtio))!=0)
    {
        perror("com set error");
        return -1;
    }
    return 0;
}


void *MuxOutputToCom5(void)
{
    int nread,i;
    char buff[512];
    char *write_buff;
    if((i = set_option(fd,115200,8,'N',1))<0)
    {
        perror("set_opt error");
        return;
    }
    while(1)
    {
        memset(buff,0,sizeof(char)*512);
        nread = 0;
        nread = read(fd,buff,256);
        if(nread >0)
        {
            if(1 == g_nread && buff[0] == 13 && buff[1] == 10)
            {

                write_buff = &buff[g_nread+1];
                nread = strlen(write_buff);
                nread = write(fd5,write_buff,nread); 
            }
            else if( g_nread > 1 && 0 == strncmp(g_buff,buff,g_nread-1))
            {   
                write_buff = &buff[g_nread+1];
                nread = write(fd5,write_buff,nread-g_nread-1);    
            }
            else
            {
                write_buff = buff;
                nread = strlen(write_buff);
                nread = write(fd5,write_buff,nread);    
            }
        }           
    }
    close(fd);
    return;
}

void *Com5InputToMux(void)
{
    int oldstdin,oldstdout;
    int nread,i;
    char buff[512];
    int uartid ;
    oldstdin = dup(0);
    oldstdout = dup(1);
    FILE *stream;
    if((stream= freopen("/usr/std.in","w+",stdin)) == NULL)
    {
        printf("freopen stdin fail\n");
        kill(getpid(),SIGINT);
    }
    if((stream = freopen("/usr/std.out","w+",stdout))== NULL)
    {
        printf("freopen stdout fail\n");
        kill(getpid(),SIGINT);
    }   
    if((i = set_option(fd,115200,8,'N',1))<0)
    {
        perror("set_opt error");
        kill(getpid(),SIGINT);
    }
    while(1)
    {
        memset(buff,0,sizeof(char)*512);
        nread = read(fd5,buff,256);
        if(nread > 0)
        {
            g_nread = 0;
            memset(g_buff,0,sizeof(char)*512);
            g_nread = strlen(buff);     
            strncpy(g_buff,buff,g_nread);
            if(nread == 0x03 &&buff[0] == 0x1b && buff[1] == 0x71)
            {
                dup2(oldstdin,0);
                dup2(oldstdout,1);
                close(fd);
                close(fd5);
                kill(getpid(),SIGINT);
            }
            else
            {
                nread = write(fd,buff,nread);

            }
        }
    }
    return;
}