linux环境编程之进程间通信（pipe & FIFO）
/***********************rw.h*******************/
#include <unistd.h>
int Read(int fd, void *buf,size_t count)
{
void *p =buf;
int totle = count;
int current = 0;
int iRet = 0;
while(current < totle)
{
iRet = read(fd,p + current,totle – current);
if(iRet < 0)
{
perror(“Read Error”);
return -1;
}
else if(iRet == 0)
{
return current;
}
else
{
current += iRet;
}
}
return current;
}
int Write(int fd,void *buf,size_t count)
{
void *p = buf;
int totle = count;
int current = 0;
int iRet = 0;
while(current < totle)
{
iRet = write(fd,p + current,totle – current);
if(iRet < 0)
{
perror(“Write Error”);
return -1;
}
else if(iRet == 0)
{
return current;
}
else
{
current += iRet;
}
}
return current;
}
/********************************************************
* name : pipe_print.c
* author : cyher
* date :2008-8-5
* descirption : 两个进程，父进程和子进程。
* 建立pipe父进程读取文件名给子进程读文件给父进程。
* 父进程打印在屏幕上。
* ********************************************************/
#include <stdio.h>
#include <unistd.h>
#include <sys/wait.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
#include “rw.h”//读管道的时候需要用这个自己写的read循环读，否则一次可能读不全
#define MAX 1024
int main (int argc,char *argv[])
{
int fd1[2];
int fd2[2];
int pipe1,pipe2;
size_t n=1;
pid_t pid;
char buf1[MAX] = {0};
char buf2[MAX] = {0};
char buf3[MAX] = {0};
int fd;
ssize_t read_num;
if(argc != 2)
{
printf(“usage:\”pipe_print name\n\”");
exit(0);
}
if((pipe1=pipe(fd1)) == -1 )//父向子传信息的管道
{
perror(“pipe1″);
exit(1);
}
if((pipe2=pipe(fd2)) == -1)//子向父传信息的管道
{
perror(“pipe2″);
exit(1);
}
if((pid=fork()) < 0)
{
perror(“fork”);
exit(1);
}
else if(pid == 0)//子进程
{
close(fd1[1]);/*关管道1写端*/
close(fd2[0]);/*关管道2读端*/
sleep(1);
if(read(fd1[0],buf2,MAX) == -1)/*读取父进程传来的文件名*/
{
exit(1);
}
if(( fd = open(buf2,O_RDONLY,0) ) < 0)/*打开文件*/
{
perror(“open error”);
exit(1);
}
while(Read(fd,buf1,MAX) > 0)/*读文件放入buf1*/
{
Write(fd2[1],buf1,MAX);/*写入管道2*/
memset(buf1,0,MAX);/*清空buf1以免出错*/
}
close(fd1[0]);
close(fd2[1]);
exit(0);
}
else//父进程
{
close(fd2[1]);/*关管道2的写端*/
close(fd1[0]);/*关管道1的读端*/
n=strlen(argv[1]);
if(Write(fd1[1],argv[1],n) == -1)/*把命令行参数发给管道1*/
{
exit(1);
}
while((read_num=Read(fd2[0],buf3,MAX)) > 0 )/*读取管道2中的信息放在buf3中*/
{
if(read_num == -1)
{
perror(“read”);
exit(1);
}
if(Write(1,buf3,MAX) < 0)/*把buf3中的信息写在表准输出上*/
{
perror(“write”);
exit(1);
}
memset(buf3,0,MAX);/*清空buf3以免出错*/
}
putchar(‘\n’);
close(fd1[1]);
close(fd2[0]);
if(waitpid(pid,NULL,0) == -1)/*父进程等待子进程关闭回收子进程资源*/
{
perror(“wait”);
exit(1);
}
}
}
/********************************************************
* name : fifo.c
* author : cyher
* date :2008-8-5
* descirption : 两个进程，父进程和子进程
* 建立FIFO父进程读取文件名传给子进程读取文件传回父进程
* 父进程再打印在屏幕上
* ********************************************************/
#include <stdio.h>
#include <unistd.h>
#include <sys/wait.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
#include “rw.h”
#define MAX 1024
int main (int argc,char *argv[])
{
int fd1,fd2,fd3,fd4;
int fifo,fifo2;
size_t n=1;
pid_t pid;
char buf1[MAX] = {0};
char buf2[MAX] = {0};
char buf3[MAX] = {0};
int fd;
ssize_t read_num;
if(argc != 2)
{
printf(“usage:\”pipe_print name\n\”");
exit(0);
}
if((fifo=mkfifo(“/tmp/cyher088″,0777)) == -1)
{
perror(“fifo”);
exit(1);
}
if((fifo2=mkfifo(“/tmp/cyher089″,0777)) == -1)
{
perror(“fifo”);
exit(1);
}
if((pid=fork()) < 0)
{
perror(“fork”);
exit(1);
}
else if(pid == 0)//子进程
{
if( ( fd1 = open(“/tmp/cyher088″,O_RDONLY,0666) ) == -1)
{
perror(“open1″);
exit(1);
}
sleep(1);
if(read(fd1,buf2,MAX) == -1)
{
perror(“read”);
exit(1);
}
if(( fd = open(buf2,O_RDONLY,0) ) < 0)
{
perror(“open error”);
exit(1);
}
if( ( fd4 = open(“/tmp/cyher089″,O_WRONLY ,0666) ) == -1)
{
perror(“open1″);
exit(1);
}
while(Read(fd,buf1,MAX) > 0)
{
Write(fd4,buf1,MAX);
memset(buf1,0,MAX);
}
close(fd1);
close(fd4);
exit(0);
}
else//父进程
{
if( ( fd3 = open(“/tmp/cyher088″,O_WRONLY ,0666) ) == -1)
{
perror(“open1″);
exit(1);
}
n=strlen(argv[1]);
if(Write(fd3,argv[1],n) == -1)
{
exit(1);
}
if( ( fd2 = open(“/tmp/cyher089″,O_RDONLY,0666) ) == -1)
{
perror(“open1″);
exit(1);
}
while((read_num=Read(fd2,buf3,MAX)) > 0 )
{
if(read_num == -1)
{
perror(“read”);
exit(1);
}
if(Write(1,buf3,MAX) < 0)
{
perror(“write”);
exit(1);
}
memset(buf3,0,MAX);
}
putchar(‘\n’);
close(fd3);
close(fd2);
if(waitpid(pid,NULL,0) == -1)
{
perror(“wait”);
exit(1);
}
}
}