网络编程 文件传输
一个功能是输入ls,显示服务端当前目录下所有文件，另一个功能是输入 download +文件名，将该文件从服务器传到客户端，为什么运行时不管输入什么命令都是服务端输出bad file descriptor，客户端输出Unsupported command,这是为什么？怎么修改？
代码如下
服务端
//server
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <dirent.h>
#include<fcntl.h>
#define BUFFER_SIZE 1024
void list_dir(int sockfd)
{
char buffer[BUFFER_SIZE];
memset(buffer, 0, sizeof(buffer));
DIR *dir;
struct dirent *entry;
if ((dir = opendir(".")) == NULL)
{
sprintf(buffer, "无法打开目录\n");
if (send(sockfd, buffer, strlen(buffer), 0) < 0) {
perror("send error");
exit(EXIT_FAILURE);
}
return;
}
while ((entry = readdir(dir)) != NULL)
{
if (entry->d_name[0] != '.')
{
strcat(buffer, entry->d_name);
strcat(buffer, "\n");
}
}
if (send(sockfd, buffer, strlen(buffer), 0) < 0)
{
perror("send error");
exit(EXIT_FAILURE);
}
}
int main(int argc, char *argv[])
{
char str[100];
char *pos;
ssize_t n;
FILE *fp;
char buffer[BUFFER_SIZE];
// 创建socket
int listenfd = socket(AF_INET, SOCK_STREAM, 0);
if (listenfd < 0)
{
perror("socket error");
exit(EXIT_FAILURE);
}
// 设置服务端地址
struct sockaddr_in servaddr;
memset(&servaddr, 0, sizeof(servaddr)); //结构体初始化
servaddr.sin_family = AF_INET;
// servaddr.sin_port = htons(argv[2]);
servaddr.sin_port = htons(atoi(argv[1]));
servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
// 绑定端口
if (bind(listenfd, (struct sockaddr *)&servaddr, sizeof(servaddr)) < 0)
{
perror("bind error");
exit(EXIT_FAILURE);
}
// 监听端口
if (listen(listenfd, 5) < 0)
{
perror("listen error");
exit(EXIT_FAILURE);
}
printf("服务端已启动，等待客户端连接...\n");
// 循环接收客户端连接
int connfd;
struct sockaddr_in cliaddr;
memset(&cliaddr, 0, sizeof(cliaddr));
socklen_t clilen = sizeof(cliaddr);
connfd = accept(listenfd, (struct sockaddr *)&cliaddr, &clilen);
if (connfd < 0)
{
perror("accept error");
}
printf("客户端 %s:%d 已连接\n", inet_ntoa(cliaddr.sin_addr), ntohs(cliaddr.sin_port));//ip地址和端口号？
// 发送欢迎信息
memset(buffer, 0, sizeof(buffer));
sprintf(buffer, "欢迎连接到服务端！");
if (send(connfd, buffer, strlen(buffer), 0) < 0)
{
perror("send error");
exit(EXIT_FAILURE);
}
// 循环接收命令并执行
while (1)
{
n = read(connfd, buffer, sizeof(buffer));
//memset(buffer, 0, sizeof(buffer));
if (n < 0)
{
perror("recv error");
exit(1);
}
if (strcmp(buffer, "exit") == 0)
{
printf("客户端 %s:%d 已断开连接\n", inet_ntoa(cliaddr.sin_addr), ntohs(cliaddr.sin_port));
break;
} else if (strcmp(buffer, "ls") == 0)
{
list_dir(connfd);
} else if(strncmp(buffer,"download ",9)==0)
{
char *filename = buffer + 9;
filename[strlen(filename)-1]='\0';
//recv(connfd,str,1024,MSG_DONTWAIT);
//pos = strchr(str, ' ');
// 打开文件
fp = fopen(filename, "rb");
if (fp == NULL)
{
// 文件不存在
strcpy(buffer, "File not found!\n");
write(connfd, buffer, strlen(buffer));
} else
{
// 读取文件并发送给客户端
while ((n = fread(buffer, 1, 1024, fp)) > 0)
{
write(connfd, buffer, n);
}
fclose(fp);
}
} else {
// 不支持的命令
strcpy(buffer, "Unsupported command!\n");
write(connfd, buffer, strlen(buffer));
}
// 关闭客户端连接
close(connfd);
}
// 关闭socket
close(listenfd);
return 0;
}
客户端
//client
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#define BUFFER_SIZE 1024
int main(int argc, char *argv[]) {
ssize_t n;
// 创建socket
int sockfd = socket(AF_INET, SOCK_STREAM, 0);
if (sockfd < 0) { perror("socket error"); exit(EXIT_FAILURE); }
// 设置服务端地址
struct sockaddr_in servaddr;
memset(&servaddr, 0, sizeof(servaddr));
servaddr.sin_family = AF_INET;
servaddr.sin_port = htons(atoi(argv[1]));
servaddr.sin_addr.s_addr = inet_addr("127.0.0.1");
// 连接服务端
if (connect(sockfd, (struct sockaddr *)&servaddr, sizeof(servaddr)) < 0)
{
perror("connect error");
exit(EXIT_FAILURE);
}
// 接收服务端欢迎信息
char buffer[BUFFER_SIZE];
memset(buffer, 0, sizeof(buffer));
if (recv(sockfd, buffer, sizeof(buffer), 0) < 0)
{
perror("recv error");
exit(EXIT_FAILURE);
}
printf("%s\n", buffer);
// 循环输入命令并接收回复
while (1)
{
// 获取用户输入的命令
printf("请输入命令：");
memset(buffer, 0, sizeof(buffer));
fgets(buffer, sizeof(buffer), stdin);
buffer[strlen(buffer) - 1] = '\0';
// 发送命令到服务器
write(sockfd, buffer, strlen(buffer));
// 读取服务器的响应
while ((n = read(sockfd, buffer, 1024)) > 0)
{
fwrite(buffer, 1, n, stdout);
}
//printf("%s\n", buffer);
}
// 关闭socket
close(sockfd);
return 0;
}
