Linux socket编程学习初步（3）--客户端向服务器请求文件

服务器端：

#include <stdio.h>#include <stdlib.h>#include <unistd.h>//read,write#include <sys/types.h>#include <sys/socket.h>#include <netinet/in.h>#include <netdb.h>#include <sys/fcntl.h>//open#include <strings.h>#define SERVER_PORT 12345#define BUF_SIZE 4096 /* block transfer size */#define QUEUE_SIZE 10 /* how many client can connect at the same time */void fatal(char *string){    printf("%s\n",string);    exit(1);}int main(/*int argc,char * argv[]*/){int s,b,l,fd,sa,bytes,on=1;char buf[BUF_SIZE]; /*buf for outgoing files*/struct sockaddr_in channel; /* hold IP address*/    /* Build address structure to bind to socket. */    bzero(&channel,sizeof(channel));    channel.sin_family=AF_INET;    channel.sin_addr.s_addr=htonl(INADDR_ANY);    channel.sin_port=htons(SERVER_PORT);    /* Passive open.Wait for connection. */    s=socket(AF_INET,SOCK_STREAM,IPPROTO_TCP);  /* Creat socket */    if(s<0) fatal("socket failed");    setsockopt(s,SOL_SOCKET,SO_REUSEADDR,(char *)&on,sizeof(on));/* use the socket for many time (up word) */    b=bind(s,(struct sockaddr *)&channel,sizeof(channel));    if(b<0) fatal("blind failed");    l=listen(s,QUEUE_SIZE);    if(l<0) fatal("listen failed"); /* Socket is now set up and bound. Wait for connection and process it. */    while(1)    {        sa=accept(s,0,0);        if(sa<0) fatal("accept failed");        recv(sa,buf,BUF_SIZE,0);     /* Get and return the file. */        fd=open(buf,O_RDONLY);        if(fd<0) fatal("open failed");        while(1)        {            bytes=read(fd,buf,BUF_SIZE);            if(bytes<=0) break;            write(sa,buf,bytes);        }        close(fd);        close(sa);    }    return 0;}

客户端：

/* *This page contains a client program that can request a flie from the server program. */#include <sys/types.h>#include <sys/socket.h>#include <netinet/in.h>#include <netdb.h>#include <arpa/inet.h>#include <string.h>#include <stdlib.h>#include <unistd.h>//read,write#include <stdio.h>#define SERVER_PORT 12345#define BUF_SIZE 4096#define PATH "/home/fupeng/Desktop/test.txt"#define DEST_IP "127.0.0.1"void fatal(char *s){printf("%s\n",s);exit(1);}int main(/*int argc,char * *argv*/){    int c,s,bytes;    char buf[BUF_SIZE];   /*buf for incoming files*/    struct sockaddr_in channel;   /* hold IP address*///    if (argc!=3)fatal("Usage:client IPaddress file-name");    s=socket(PF_INET,SOCK_STREAM,IPPROTO_TCP);    if(s<0)fatal("socket");    bzero(&channel,sizeof(channel));    channel.sin_family=AF_INET;    channel.sin_port=htons(SERVER_PORT);    if(inet_aton(DEST_IP,&channel.sin_addr)==0)    { /* use the ASCII ip for the  server's sin_addr. */        fprintf(stderr,"Inet_aton erro\n");        exit(1);    }    c=connect(s,(struct sockaddr *)&channel,sizeof(channel));    if(c<0)fatal("connetct failed");//    send(s,argv[2],strlen(argv[2]),0);    send(s,PATH,strlen(PATH),0);//BY FUPENG   /* Go get the file and write it to standard output.*/while(1){bytes=read(s,buf,BUF_SIZE);if(bytes<=0) exit(0); write(1,buf,bytes);}}

给出了客户端由服务器获取一个文件的例子。
获取的文件将直接显示在终端界面上。