linux客户端实现（发送文件）

  
#include <netinet/in.h>    // for sockaddr_in
#include <sys/types.h>    // for socket
#include <sys/socket.h>    // for socket
#include <stdio.h>        // for printf
#include <stdlib.h>        // for exit
#include <string.h>        // for bzero
/*
 #include
 #include
 #include
 #include
 */

#define SERVER_PORT 6666
#define BUFFER_SIZE 1024
#define FILE_NAME_MAX_SIZE 512

int main(int argc, char **argv)
{
    if (argc != 2)
    {
        printf("Please input the IP address of the server \n", argv[0]);
        exit(1);
    }

    //设置一个socket地址结构client_addr,代表客户机internet地址, 端口
    struct sockaddr_in client_addr;
    bzero(&client_addr, sizeof(client_addr)); //把一段内存区的内容全部设置为0
    client_addr.sin_family = AF_INET; //internet协议族
    client_addr.sin_addr.s_addr = htons(INADDR_ANY); //INADDR_ANY表示自动获取本机地址
    client_addr.sin_port = htons(0); //0表示让系统自动分配一个空闲端口
    //创建用于internet的流协议(TCP)socket,用client_socket代表客户机socket
    int client_socket = socket(AF_INET, SOCK_STREAM, 0);
    if (client_socket < 0)
    {
        printf("Create Socket Failed!\n");
        exit(1);
    }
    //把客户机的socket和客户机的socket地址结构联系起来
    if (bind(client_socket, (struct sockaddr*) &client_addr,
            sizeof(client_addr)))
    {
        printf("Client Bind Port Failed!\n");
        exit(1);
    }

    //设置一个socket地址结构server_addr,代表服务器的internet地址, 端口
    struct sockaddr_in server_addr;
    bzero(&server_addr, sizeof(server_addr));
    server_addr.sin_family = AF_INET;
    if (inet_aton(argv[1], &server_addr.sin_addr) == 0) //服务器的IP地址来自程序的参数
    {
        printf("Server IP Address Error! \n");
        exit(1);
    }

    server_addr.sin_port = htons(SERVER_PORT);
    socklen_t server_addr_length = sizeof(server_addr);
    // 向服务器发起连接,连接成功后client_socket代表了客户机和服务器的一个socket连接
    if (connect(client_socket, (struct sockaddr*) &server_addr,
            server_addr_length) < 0)
    {
        printf("Can Not Connect To %s!\n", argv[1]);
        exit(1);
    }

    // 连接上服务器, 选择要上传的文件
    char file_name[FILE_NAME_MAX_SIZE + 1];bzero
    (file_name, FILE_NAME_MAX_SIZE + 1);
    printf("Please Input File Name Upload To Server: ");
    scanf("%s", file_name);

    char buffer[BUFFER_SIZE];
    bzero(buffer, BUFFER_SIZE);
    strncpy(buffer, file_name,
            strlen(file_name) > BUFFER_SIZE? BUFFER_SIZE : strlen(file_name));

    FILE * fp = fopen(file_name, "r");
    if (NULL == fp)
    {
        printf("File: %s NOT FOUND! \n", file_name);
        exit(1);
    }

    // 发送文件名
    int nameLength = send(client_socket, buffer, BUFFER_SIZE, 0);
    if (nameLength < 0)
    {
        printf("File name Error! \n");
        exit(0);
    }

    bzero(buffer, BUFFER_SIZE);
    int file_block_length = 0;

    while ((file_block_length = fread(buffer, sizeof(char), BUFFER_SIZE, fp)) > 0)
    {
        if (send(client_socket, buffer, file_block_length, 0) < 0)
        {
            printf("Send File:\t%s Failed\n", file_name);
            break;
        }
        bzero(buffer, BUFFER_SIZE);
    }
    printf("File:\t%s Transfer Finished\n", file_name);
    fclose(fp);
    close(client_socket);
    return 0;
}