学习参考文章:
链接: https://blog.youkuaiyun.com/qq_46518045/article/details/113482400.
ls:查看当前文件
lls:查看服务器文件
cd+空格+文件名(…),服务器进入文件夹或返回上一级
lcd+空格+文件名(…),本地进入文件夹或返回上一级
get+空格+文件名:得到服务器文件
put+空格+文件名: 发送给服务器
服务端:
#include<stdio.h>
#include<sys/types.h> /* See NOTES */
#include<sys/socket.h>
#include<arpa/inet.h>
#include<netinet/in.h>
#include<stdlib.h>
#include<unistd.h>
#include<string.h>
#include<sys/stat.h>
#include<fcntl.h>
int change(char cmd[128])//change函数负责获取发送过来的指令,将之转化为整数。strcmp,strstr
{
if(!strcmp("lls",cmd))
{
return 1;
}
else if(strstr(cmd,"lcd")!=NULL)
{ return 2;
}
else if(!strcmp("g",cmd))
{ return 3;
}
else if(!strcmp("ls",cmd))
{ return 4;
}
else if(strstr(cmd,"cd")!=NULL)
{ return 5;
}
else if(strstr(cmd,"get")!=NULL)
{
return 6;
}
else if(strstr(cmd,"put")!=NULL)
{ return 7;
}
}
char *getbehind(char cmd[128])//char *strtok(char s[], const char *delim);分解字符串为一组字符串。s为要分解的字符串,delim为分隔符字符串。
{
char *p;
p = (char *)malloc(128);//获取文件路径名
p = strtok(cmd," ");
p = strtok(NULL," ");
return p;
}
void getmessage(char cmd[128],int cfd)
{
char readbuf[8000];
char *p=getbehind(cmd);
read(cfd,readbuf,8000);
if(strlen(readbuf) != strlen("NO file")){
int fd = open(p,O_RDWR|O_CREAT,0666);//读写文件操作,open函数 int open(const char *pathname, int flags,mode_t mode);
write(fd,readbuf,strlen(readbuf));
printf("receive successfully\n");
close(fd);
memset(readbuf,0,8000);
}
else{
printf("NO file\n");
}
}
void putmessage(char cmd[128],int c_fd)
{
int sfd;
char *p = (char *)malloc(8000);
memset(p,0,8000);
char *readbuf = (char *)malloc(128);
readbuf = getbehind(cmd);
if(access(readbuf,F_OK) == -1){
printf("No file\n");//F_OK 值为0,判断文件是否存在
}
else{
sfd = open(readbuf,O_RDWR,0666);
read(sfd,p,8000);
write(c_fd,p,strlen(p));
close(sfd);
memset(p,0,8000);
}
}
void choosecmd(char cmd[128],int c_fd)
{
FILE *fdb;
int ret = change(cmd);
char freadbuf[128];
char *p = (char *)malloc(8000);
switch(ret){
case 1:
system("ls");
break;
case 2:
p = getbehind(cmd);
chdir(p);// int chdir(const char *path);//函数说明:chdir()用户将当前的工作目录改变成以参数路径所指的目录。
memset(p,0,8000);
break;
case 3:
printf("unconnecting\n");
write(c_fd,"away host",128);
close(c_fd);
exit(-1);
break;
case 4:
read(c_fd,p,1024);
printf("%s\n",p);
memset(p,0,1024);
break;
case 5:
printf("host folder open or exit successful\n");
break;
case 6:
getmessage(cmd,c_fd);
break;
case 7:
putmessage(cmd,c_fd);
break;
}
}
int main(int argc,char **argv)
{
//socket
struct sockaddr_in s_addr;
struct sockaddr_in c_addr;
char Writebuf[128];
char Readbuf[128];
int nread;
int clen;
int s_fd;
int c_fd;
s_fd = socket(AF_INET, SOCK_STREAM,0);
if(s_fd == -1){
perror("socket");
exit(-1);
}
if(argc!=3){
perror("argc");
exit(0);
}
memset(&s_addr,0,sizeof(struct sockaddr_in));
s_addr.sin_family = AF_INET;
s_addr.sin_port = htons(atoi(argv[2]));
inet_aton(argv[1],&s_addr.sin_addr);
//bind
bind(s_fd,(struct sockaddr *)&s_addr,sizeof(struct sockaddr_in));
//listen
listen(s_fd,10);
//accept
printf("wait connecting\n");
memset(&c_addr,0,sizeof(struct sockaddr_in));
clen = sizeof(struct sockaddr_in);
while(1){
c_fd = accept(s_fd,(struct sockaddr *)&c_addr,&clen);
if(c_fd == -1){
perror("accept");
exit(-1);
}
printf("connect,%s\n",inet_ntoa(c_addr.sin_addr));
//read
if(fork() == 0){
while(1){
nread = read(c_fd, Readbuf,128);
choosecmd(Readbuf,c_fd);
// printf("nread:%d,get from IP context:%s\n",nread,Readbuf);
memset(Readbuf,0,sizeof(Readbuf));
}
}
}
return 0;
}
客户端:
#include<stdio.h>
#include<sys/types.h> /* See NOTES */
#include<sys/socket.h>
#include<arpa/inet.h>
#include<netinet/in.h>
#include<stdlib.h>
#include<unistd.h>
#include<string.h>
#include<sys/stat.h>
#include<fcntl.h>
//lls,lcd分别命令服务端测ls,cd指令。
int change(char cmd[128])//change函数负责获取发送过来的指令,将之转化为整数。strcmp,strstr
{
if(!strcmp("lls",cmd))
{
return 1;
}
else if(strstr(cmd,"lcd")!=NULL)
{
return 2;
}
else if(!strcmp("g",cmd))
{
return 3;
}
else if(!strcmp("ls",cmd))
{
return 4;
}
else if(strstr(cmd,"cd")!=NULL)
{
return 5;
}
else if(strstr(cmd,"get")!=NULL)
{
return 6;
}
else if(strstr(cmd,"put")!=NULL)
{
return 7;
}
}
char *getbehind(char cmd[128])//char *strtok(char s[], const char *delim);分解字符串为一组字符串。s为要分解的字符串,delim为分隔符字符串。
{
char *p;
p = (char *)malloc(128);//获取文件路径名
p = strtok(cmd," ");
p = strtok(NULL," ");
return p;
}
void getmessage(char cmd[128],int cfd)
{
char readbuf[8000];
char *p=getbehind(cmd);
read(cfd,readbuf,8000);
if(strlen(readbuf) != strlen("NO file")){
int fd = open(p,O_RDWR|O_CREAT,0666);//读写文件操作,open函数 int open(const char *pathname, int flags,mode_t mode);
write(fd,readbuf,strlen(readbuf));
printf("receive successfully\n");
close(fd);
memset(readbuf,0,8000);
}
else{
printf("NO file\n");
}
}
void putmessage(char cmd[128],int c_fd)
{
int sfd;
char *p = (char *)malloc(8000);
memset(p,0,8000);
char *readbuf = (char *)malloc(128);
readbuf = getbehind(cmd);
if(access(readbuf,F_OK) == -1){
printf("No file\n");
}
else{
sfd = open(readbuf,O_RDWR,0666);
read(sfd,p,8000);
write(c_fd,p,strlen(p));
close(sfd);
memset(p,0,8000);
}
}
void choosecmd(char cmd[128],int c_fd)
{
FILE *fdb;
int ret = change(cmd);
char freadbuf[128];
char *p = (char *)malloc(8000);
switch(ret){
case 1:
system("ls");
break;
case 2:
p = getbehind(cmd);
chdir(p);// int chdir(const char *path);
memset(p,0,8000);
break;
case 3:
printf("unconnecting\n");
write(c_fd,"away host",128);
close(c_fd);
exit(-1);
break;
case 4:
read(c_fd,p,1024);
printf("%s\n",p);
memset(p,0,1024);
break;
case 5:
printf("host folder open or exit successful\n");
break;
case 6:
getmessage(cmd,c_fd);
break;
case 7:
putmessage(cmd,c_fd);
break;
}
}
// int socket(int domain, int type, int protocol);
int main(int argc,char **argv)
{
//socket
char Readbuf[1024];
char Writebuf[128];
struct sockaddr_in c_addr;
int clent;
int c_fd;
int nread;
char buf[256];
if(argc != 3){
perror("argc");
exit(1);
}
c_fd = socket(AF_INET, SOCK_STREAM,0);
if(c_fd == -1){
perror("socket");
exit(-1);
}
memset(&c_addr,0,sizeof(struct sockaddr_in));
c_addr.sin_family = AF_INET;
c_addr.sin_port = htons(atoi(argv[2]));
inet_aton(argv[1],&c_addr.sin_addr);
//connect
// int connect(int sockfd, const struct sockaddr *addr, socklen_t addrlen);
clent = sizeof(struct sockaddr_in);
if(connect(c_fd,(struct sockaddr *)&c_addr,clent)){
perror("connect");
exit(-1);
}
//write send
printf("connect...\n");
while(1){
gets(Writebuf);
printf("cmd:%s\n",Writebuf);
write(c_fd,Writebuf,strlen(Writebuf));
choosecmd(Writebuf,c_fd);
printf("*cmd*\n");
memset(Writebuf,0,strlen(Writebuf));
}
return 0;
}
代码讲解:
1.首先change函数将各种命令(字符串形式转化为整形数字,方便choosecmd函数使用)
2.char*函数getbehind获取文件的路径名,如"cd /GYJ"命令,该函数获取到"/GYJ"路径名
3.getmessage函数,从cfd标识符对应的文件中读取内容,
4.putmessage函数,先判断文件是否存在,将读到的p写入c_fd中,
5.choose函数根据change函数转化为的整形,执行相应的命令。
Main函数中,传ip地址,端口号。
首先根据上几节的内容,搭建服务端和客户端,服务端,while(1)不断收到连接请求,一旦收到请求,立刻创建一个子进程去执行choosecmd函数。
客户端不断向服务端发送请求。
(师上官可编程)
(参考kpler)
本文详细介绍了如何实现TCP/IP通信的服务端和客户端。服务端通过socket监听连接,接收并处理客户端请求,包括文件操作(如ls、cd、get、put等)。客户端则向服务端发送命令,进行文件传输或执行服务器端的操作。主要涉及的函数有change(命令解析)、getbehind(获取文件路径)、getmessage和putmessage(文件传输)。整个过程涉及文件读写、网络通信和系统调用。
582

被折叠的 条评论
为什么被折叠?



