管道客户服务端程序
管道包括无名管道和有名管道（FIFO），前者只能用于父进程和子进程之间的通信，后者可用于运行同一系统中的任意两个进程间通信。
注意：必须在系统调用fork()前调用pipe()，否则子进程将不会继承文件描述符（fd[0],fd[1]）,否则，则是创建两个管道。
#include <unistd.h>#include <stdio.h>
#include <strings.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <pthread.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>
void client(int,int);
void server(int,int);
#define MAXLINE 1024
int main(int argc,char **argv)
{
int pause=1;
int pipe1[2],pipe2[2];
pid_t childpid;
pipe(pipe1);
pipe(pipe2);
if((childpid = fork()) == 0){
close(pipe1[1]);
close(pipe2[0]);
server(pipe1[0],pipe2[1]);
exit(0);
}
close(pipe1[0]);
close(pipe2[1]);
client(pipe2[0],pipe1[1]);
waitpid(childpid,NULL,0);
exit(0);
}
void
client(int readfd, int writefd)
{
size_t len;
ssize_t n;
char buff[MAXLINE];
/* 4read pathname */
fgets(buff, MAXLINE, stdin);
len = strlen(buff); /* fgets() guarantees null byte at end */
if (buff[len-1] == '\n')
len--; /* delete newline from fgets() */
/* 4write pathname to IPC channel */
write(writefd, buff, len);
/* 4read from IPC, write to standard output */
while ( (n = read(readfd, buff, MAXLINE)) > 0)
write(STDOUT_FILENO, buff, n);
}
void
server(int readfd, int writefd)
{
int fd;
ssize_t n;
char buff[MAXLINE+1];
/* 4read pathname from IPC channel */
if ( (n = read(readfd, buff, MAXLINE)) == 0)
//err_quit("end-of-file while reading pathname");
buff[n] = '\0'; /* null terminate pathname */
if ( (fd = open(buff, O_RDONLY)) < 0) {
/* 4error: must tell client */
snprintf(buff + n, sizeof(buff) - n, ": can't open, %s\n",
strerror(errno));
n = strlen(buff);
write(writefd, buff, n);
} else {
/* 4open succeeded: copy file to IPC channel */
while ( (n = read(fd, buff, MAXLINE)) > 0)
write(writefd, buff, n);
close(fd);
}
}
test.conf文件放在/ 目录下，内容如下：//test.conf test ok!运行结果截图
