帮我完成对应要求代码

根据您提供的《linux远程终端管理系统.doc》文档内容，我将帮助您概述如何完成该项目的主要部分。由于代码量较大，这里仅提供关键部分的示例代码和指导，您可以在此基础上进一步开发和完善。

### 1. 服务器与客户端的基本框架

#### 1.1 服务器端 (server.c)

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <sys/socket.h>
#include <pthread.h>

#define PORT 8888
#define MAX_CLIENTS 10
#define BUFFER_SIZE 1024

typedef struct {
    int data_type;
    char name[20];
    char data[BUFFER_SIZE];
} Protocol;

int client_sockets[MAX_CLIENTS];
int client_count = 0;

void *handle_client(void *client_socket) {
    int sock = *(int *)client_socket;
    Protocol packet;
    
    while (1) {
        int bytes_received = read(sock, &packet, sizeof(packet));
        if (bytes_received <= 0) break;

        switch (packet.data_type) {
            case 0: // 登录
                printf("Login request from %s\n", packet.name);
                // 处理登录逻辑
                break;
            case 1: // 注册
                printf("Register request from %s\n", packet.name);
                // 处理注册逻辑
                break;
            case 2: // 消息
                printf("Message from %s: %s\n", packet.name, packet.data);
                // 处理消息逻辑
                break;
            case 3: // 心跳
                printf("Heartbeat from %s\n", packet.name);
                // 处理心跳逻辑
                break;
            case 4: // 命令
                printf("Command from %s: %s\n", packet.name, packet.data);
                // 处理命令逻辑
                break;
            default:
                printf("Unknown packet type\n");
                break;
        }
    }

    close(sock);
    for (int i = 0; i < client_count; i++) {
        if (client_sockets[i] == sock) {
            client_sockets[i] = client_sockets[--client_count];
            break;
        }
    }
    pthread_exit(NULL);
}

int main() {
    int server_fd, new_socket;
    struct sockaddr_in address;
    int addrlen = sizeof(address);

    if ((server_fd = socket(AF_INET, SOCK_STREAM, 0)) == 0) {
        perror("Socket creation failed");
        exit(EXIT_FAILURE);
    }

    memset(&address, 0, sizeof(address));
    address.sin_family = AF_INET;
    address.sin_addr.s_addr = INADDR_ANY;
    address.sin_port = htons(PORT);

    if (bind(server_fd, (struct sockaddr *)&address, sizeof(address)) < 0) {
        perror("Bind failed");
        exit(EXIT_FAILURE);
    }

    if (listen(server_fd, 3) < 0) {
        perror("Listen failed");
        exit(EXIT_FAILURE);
    }

    while (1) {
        if ((new_socket = accept(server_fd, (struct sockaddr *)&address, (socklen_t*)&addrlen)) < 0) {
            perror("Accept failed");
            continue;
        }

        if (client_count >= MAX_CLIENTS) {
            close(new_socket);
            continue;
        }

        client_sockets[client_count++] = new_socket;
        pthread_t thread_id;
        pthread_create(&thread_id, NULL, handle_client, (void *)&new_socket);
    }

    return 0;
}

#### 1.2 客户端 (client.c)

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <sys/socket.h>

#define SERVER_IP "127.0.0.1"
#define PORT 8888
#define BUFFER_SIZE 1024

typedef struct {
    int data_type;
    char name[20];
    char data[BUFFER_SIZE];
} Protocol;

int main() {
    int sock = socket(AF_INET, SOCK_STREAM, 0);
    if (sock < 0) {
        perror("Socket creation failed");
        exit(EXIT_FAILURE);
    }

    struct sockaddr_in server_address;
    memset(&server_address, 0, sizeof(server_address));
    server_address.sin_family = AF_INET;
    server_address.sin_port = htons(PORT);
    inet_pton(AF_INET, SERVER_IP, &server_address.sin_addr);

    if (connect(sock, (struct sockaddr *)&server_address, sizeof(server_address)) < 0) {
        perror("Connection failed");
        exit(EXIT_FAILURE);
    }

    Protocol packet;
    packet.data_type = 0; // 示例：登录请求
    strcpy(packet.name, "username");
    strcpy(packet.data, "password");

    send(sock, &packet, sizeof(packet), 0);

    char buffer[BUFFER_SIZE];
    int bytes_received = recv(sock, buffer, BUFFER_SIZE, 0);
    if (bytes_received > 0) {
        buffer[bytes_received] = '\0';
        printf("Server response: %s\n", buffer);
    }

    close(sock);
    return 0;
}

### 2. 主要功能实现

#### 2.1 注册功能
在 `handle_client` 函数中添加注册逻辑：

case 1: // 注册
    printf("Register request from %s\n", packet.name);
    // 检查用户名是否已存在
    // 如果不存在，保存到用户链表和文件中
    // 发送注册成功或失败的消息给客户端
    break;

#### 2.2 登录功能
在 `handle_client` 函数中添加登录逻辑：

case 0: // 登录
    printf("Login request from %s\n", packet.name);
    // 检查用户名和密码是否正确
    // 如果正确，添加到在线链表
    // 发送登录成功或失败的消息给客户端
    break;

#### 2.3 远程命令功能
在 `handle_client` 函数中添加命令执行逻辑：

case 4: // 命令
    printf("Command from %s: %s\n", packet.name, packet.data);
    FILE *fp;
    char path[1035];

    fp = popen(packet.data, "r");
    if (fp == NULL) {
        printf("Failed to run command\n");
        break;
    }

    while (fgets(path, sizeof(path)-1, fp) != NULL) {
        write(client_socket, path, strlen(path));
    }

    pclose(fp);
    break;

#### 2.4 心跳机制
在客户端中添加心跳发送逻辑：

void send_heartbeat(int sock) {
    Protocol packet;
    packet.data_type = 3; // 心跳包
    strcpy(packet.name, "username");
    strcpy(packet.data, "");

    while (1) {
        send(sock, &packet, sizeof(packet), 0);
        sleep(3);
    }
}

int main() {
    // ... (之前的代码)

    pthread_t heartbeat_thread;
    pthread_create(&heartbeat_thread, NULL, (void*)send_heartbeat, (void*)sock);

    // ... (主逻辑)

    pthread_join(heartbeat_thread, NULL);
    return 0;
}

#### 2.5 聊天功能
在 `handle_client` 函数中添加聊天逻辑：

case 2: // 消息
    printf("Message from %s: %s\n", packet.name, packet.data);
    // 遍历在线链表找到聊天对象
    // 将消息发送给聊天对象
    break;

### 3. 日志记录
在服务器端添加日志记录功能：

void log_message(const char *message) {
    FILE *log_file = fopen("server.log", "a");
    if (log_file == NULL) {
        perror("Log file open failed");
        return;
    }

    fprintf(log_file, "%s\n", message);
    fclose(log_file);
}

// 在适当的地方调用 log_message 函数

### 4. 异常处理
在服务器端添加心跳异常处理逻辑：

void check_heartbeats() {
    time_t current_time = time(NULL);
    for (int i = 0; i < client_count; i++) {
        if (difftime(current_time, last_heartbeat_times[i]) > 15) {
            printf("Client %d disconnected due to heartbeat timeout\n", client_sockets[i]);
            close(client_sockets[i]);
            // 从在线链表中移除该客户端
            for (int j = i; j < client_count - 1; j++) {
                client_sockets[j] = client_sockets[j + 1];
            }
            client_count--;
        }
    }
}

// 在主线程中定期调用 check_heartbeats 函数

以上代码提供了项目的基架和一些关键功能的实现示例。您可以在此基础上继续完善其他功能和细节。如果有更具体的需求或问题，请随时告知。