Linux系统编程——DIY编写Linux中的FTP(客户端与服务器)
Linux
C语言
函数,指针,结构体
Linux套接字,进程,多种输入输出函数,网络编程,底层调用
客户端程序连接到服务器后,可通过ls,lls,pwd,put等多种指令操作服务器端文件,打印文件路径,下载上传文件
// 终端1
gcc ftp_server.c -o server
./server 192.168.3.8 8000
---
// 终端2
gcc ftp_client.c -o client
./client 192.168.3.8 8000
---
//可发送指令
ls
pwd
lls
lcd
quit
get xxx
put xxx
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#define LS 0
#define GET 1
#define PWD 2
#define IFGO 3
#define LCD 4
#define LLS 5
#define CD 6
#define PUT 7
#define QUIT 8
#define DOFILE 9
struct Msg
{
int type;
char data[1024];
char secondBuf[128];
};
int get_cmd_type(char *cmd)
{
if(!strcmp("ls",cmd)) return LS;
if(!strcmp("quit",cmd)) return QUIT;
if(!strcmp("pwd",cmd)) return PWD;
if(strstr(cmd,"cd")!=NULL) return CD;
if(strstr(cmd,"get")!=NULL) return GET;
if(strstr(cmd,"put")!=NULL) return PUT;
return 100;
}
//分割字符串
char *getDesDir(char *cmsg)
{
char *p;
p = strtok(cmsg,"");
p = strtok(NULL,"");
return p;
}
void msg_handler(struct Msg msg,int fd)
{
char dataBuf[1024] = {
0};
char *file = NULL;
int fdfile;
//msg.data为数组字符串类型
printf("cmd:%s\n",msg.data);
//将字符串转换为整型数
int ret = get_cmd_type(msg.data);
switch(ret)
{
case LS:
//输出当前路径
case PWD:
msg.type = 0;
FILE *r = popen(msg.data,"r");
fread(msg.data, sizeof(msg.data),1,r);
write(fd, &msg, sizeof(msg));
break;
case CD:
msg.type = 1;
//分割字符串
char *dir = getDesDir(msg.data);
printf("dir:%s\n",dir);
chdir(dir);
break;
case GET:
//分割字符串
file = getDesDir(msg.data);
if(access(file,F_OK) == -1)
{
strcpy(msg.data,"No this file!");
write(fd,&msg,sizeof(msg));
}
else
{
msg.type = DOFILE;
fdfile = open(file,O_RDWR);
read(fdfile,dataBuf,sizeof(dataBuf));
close(fdfile);
strcpy(msg.data,dataBuf);
write(fd,&msg,sizeof(msg));
}
break;
case PUT:
fdfile = open(getDesDir(msg.data),O_RDWR|O_CREAT,0666);
write(fdfile, msg.secondBuf, strlen(msg.secondBuf));
close(fdfile);
break;
case QUIT:
printf("client quit!\n");
exit(-1);
}
}
int main(int argc, char **argv)
{
int s_fd;
int c_fd;
int n_read;
char readBuf[128];
struct sockaddr_in s_addr;
struct sockaddr_in c_addr;
struct Msg msg;
if(argc != 3)
{
printf("Unqualified parameters!\n");
exit(-1);
}
memset(&s_addr,0,sizeof(struct sockaddr_in));
memset(&c_addr,0,sizeof(struct sockaddr_in));
//1.socket
s_fd = socket(AF_INET, SOCK_STREAM, 0);
if(s_fd == -1)
{
perror("socket");
exit(-1);
}
s_addr.sin_family = AF_INET;
s_addr.sin_port = htons(atoi(argv[2]));
inet_aton("argv[1]",&s_addr.sin_addr);
//2.bind
bind(s_fd,(struct sockaddr *)&s_addr,sizeof(struct sockaddr_in));
//3.listen
listen(s_fd,10);
//4.accept
int clen = sizeof(struct sockaddr_in);
while(1)
{
c_fd = accept(s_fd,(struct sockaddr *)&c_addr,&clen);
if(c_fd == -1)
perror("accept");
printf("get connect:%s\n",inet_ntoa(c_addr.sin_addr));
//当新的客户端接入的时候才创建子进程
//一个子进程负责一条连接通道
if(fork() == 0)
{
while(1)
{
memset(msg.data,0,sizeof(msg.data));
//等待输入,将所有数据都传到msg结构体中
n_read = read(c_fd,&msg,sizeof(msg));
if(n_read == 0)
{
printf("client out\n");
break;
}
else if(n_read > 0)
{
msg_handler(msg,c_fd);
}
}
}
}
close(c_fd);
close(s_fd);
return 0;
}
#include
#include
#include
#include
#include
#include
#include
#include
#include
#define LS 0
#define GET 1
#define PWD 2
#define IFGO 3
#define LCD 4
#define LLS 5
#define CD 6
#define PUT 7
#define QUIT 8
#define DOFILE 9
struct Msg
{
int type;
char data[1024];
char secondBuf[128];
};
char *getdir(char *cmd)
{
char *p;
p = strtok(cmd," ");
p = strtok(NULL," ");
return p;
}
int get_cmd_type(char *cmd)
{
if(strstr(cmd,"lcd")) return LCD;
if(!strcmp("quit",cmd)) return QUIT;
if(!strcmp("ls",cmd)) return LS;
if(!strcmp("lls",cmd)) return LLS;
if(!strcmp("pwd",cmd)) return LS;
if(strstr(cmd,"cd")) return CD;
if(strstr(cmd,"get")) return GET;
if(strstr(cmd,"put")) return PUT;
return -1;
}
int cmd_handler(struct Msg msg, int fd)
{
char *dir = NULL;
char buf[32];
int ret;
int filefd;
//将字符串转换为宏
ret = get_cmd_type(msg.data);
switch(ret)
{
case LS:
case CD:
case PWD:
msg.type = 0;
//发送给宏
write(fd, &msg, sizeof(msg));
break;
case GET:
msg.type = 2;
write(fd, &msg,sizeof(msg));
break;
case PUT:
strcpy(buf, msg.data);
dir = getdir(buf);
if(access(dir, F_OK) == -1)
{
printf("%s not exsit\n",dir);
}
else
{
filefd = open(dir, O_RDWR);
read(filefd,msg.secondBuf,sizeof(msg.secondBuf));
close(filefd);
write(fd, &msg,sizeof(msg));
}
break;
case LLS:
system("ls");
break;
case LCD:
dir = getdir(msg.data);
chdir(dir);
break;
case QUIT:
strcpy(msg.data,"quit");
write(fd,&msg,sizeof(msg));
close(fd);
exit(-1);
}
return ret;
}
void handler_server_message(int c_fd,struct Msg msg)
{
int n_read;
struct Msg msgget;
int newfilefd;
//读取服务器数据
n_read = read(c_fd, &msgget,sizeof(msgget));
//连接断开
if(n_read == 0)
{
printf("server is out,quit\n");
exit(-1);
}
else if(msgget.type == DOFILE)
{
char *p = getdir(msg.data);
newfilefd = open(p,O_RDWR|O_CREAT,0600);
write(newfilefd,msgget.data,strlen(msgget.data));
putchar('>');
fflush(stdout);
}
else
{
printf("--------------------------------------\n");
printf("\n%s\n",msgget.data);
printf("--------------------------------------\n");
putchar('>');
fflush(stdout);
}
}
int main(int argc, char **argv)
{
int c_fd;
struct sockaddr_in c_addr;
struct Msg msg;
memset(&c_addr, 0, sizeof(struct sockaddr_in));
if(argc != 3)
{
printf("param is not good\n");
exit(-1);
}
//1.socket
c_fd = socket(AF_INET, SOCK_STREAM, 0);
if(c_fd == -1)
{
perror("socket");
exit(-1);
}
c_addr.sin_family = AF_INET;
c_addr.sin_port = htons(atoi(argv[2]));
inet_aton("argv[1]", &c_addr.sin_addr);
//2.connect
if(connect(c_fd, (struct sockaddr *)&c_addr, sizeof(struct sockaddr)) == -1)
{
perror("connect");
exit(-1);
}
printf("connect ...\n");
int mark = 0;
while(1)
{
memset(msg.data, 0, sizeof(msg.data));
if(mark == 0) printf(">");
//接收用户输入
gets(msg.data);
//规范格式
if(strlen(msg.data) == 0)
{
if(mark == 1)
{
printf(">");
}
continue;
}
mark = 1;
//调用处理
int ret = cmd_handler(msg,c_fd);
if(ret >IFGO)
{
putchar('>');
fflush(stdout);
continue;
}
if(ret == -1)
{
printf("command not \n");
printf(">");
fflush(stdout);
continue;
}
handler_server_message(c_fd, msg);
}
return 0;
}
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