Error: listen tcp 127.0.0.1:11434: bind: Only one usage

这个错误信息通常在尝试启动网络服务或监听端口时出现，特别是当你试图在同一台机器上使用同一个IP地址和端口启动多个服务时。"Error: listen tcp 127.0.0.1:11434: bind: Only one usage" 的意思是操作系统不允许一个端口被多次绑定。在TCP/IP协议中，127.0.0.1是本地回环地址，11434是你尝试监听的端口号。

具体来说，这可能意味着：

1. 有一个现有的进程已经在127.0.0.1:11434上运行并占用该端口，你需要先关闭那个进程才能重新绑定。
2. 你可能尝试在同一进程中多次调用`listen()`函数，但一个套接字（socket）只能在一个特定时间监听一个端口。

解决这个问题的方法有：
- 检查是否有其他正在运行的服务使用了该端口，使用`netstat`或`lsof`命令查看。
- 如果你确信要启动的服务没有在运行，可以使用`kill`命令关闭占用该端口的进程。
- 在编程中，确保在初始化服务之前，已经正确关闭了之前的监听或套接字。

相关问题

文件服务器提供文件下载的服务器，在一个端口进行监听，通过接受客户端的命令实现相应的行为：例如发送相应的文件给客户端。客户端连接到服务器的端口，通过输入命令行可以得到服务器的文件列表，并且可以通过命令行下载服务器上的文件。 1. 开发语言不限，可以是C、Java等语言。 2. 可以是UDP、可以是TCP 例如，服务器命令行运行： FileServer.exe D:/fileFolder FileServer.exe 是文件服务器的程序，后面的参数表示共享的文件夹。文件夹中可以事先准备一些文件。 客户端命令行启动： FileClient.exe 127.0.0.1 8080 FileClient.exe 是客户端程序，127.0.0.1是服务器的IP地址；8080是需要连接的服务器端口。 1. 客户端可以通过下载命令下载服务器上的文件，例如： download view.jpg 下载的文件可以保存在客户端运行的当前目录当中。注意如果在一个机器上运行，客户端和服务器不要在同一个目录下运行，可能产生文件冲突。

好的，这个问题需要用到 TCP/IP 协议和套接字编程。下面是一个简单的 C 语言实现文件服务器和客户端的代码：

文件服务器代码：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <unistd.h>
#include <fcntl.h>
#include <arpa/inet.h>

#define BUF_SIZE 1024

void error_handling(char *message);

int main(int argc, char *argv[])
{
    int serv_sock, clnt_sock;
    char buf[BUF_SIZE];
    int file_fd, len, read_len, write_len;
    struct sockaddr_in serv_addr, clnt_addr;
    socklen_t clnt_addr_size;
    char file_path[BUF_SIZE];
    char file_name[BUF_SIZE];
    char tmp[BUF_SIZE];

    if (argc != 2) {
        printf("Usage: %s <file_path>\n", argv[0]);
        exit(1);
    }

    strcpy(file_path, argv[1]);

    serv_sock = socket(PF_INET, SOCK_STREAM, 0);
    if (serv_sock == -1)
        error_handling("socket() error");

    memset(&serv_addr, 0, sizeof(serv_addr));
    serv_addr.sin_family = AF_INET;
    serv_addr.sin_addr.s_addr = htonl(INADDR_ANY);
    serv_addr.sin_port = htons(8080);

    if (bind(serv_sock, (struct sockaddr*)&serv_addr, sizeof(serv_addr)) == -1)
        error_handling("bind() error");

    if (listen(serv_sock, 5) == -1)
        error_handling("listen() error");

    while (1) {
        clnt_addr_size = sizeof(clnt_addr);
        clnt_sock = accept(serv_sock, (struct sockaddr*)&clnt_addr, &clnt_addr_size);
        if (clnt_sock == -1)
            error_handling("accept() error");

        printf("Client %s connected.\n", inet_ntoa(clnt_addr.sin_addr));

        while (1) {
            memset(buf, 0, BUF_SIZE);
            len = read(clnt_sock, buf, BUF_SIZE);
            if (len == -1)
                error_handling("read() error");

            if (strcmp(buf, "quit") == 0) {
                printf("Client %s disconnected.\n", inet_ntoa(clnt_addr.sin_addr));
                close(clnt_sock);
                break;
            } else if (strcmp(buf, "ls") == 0) {
                FILE *fp;
                char cmd[BUF_SIZE];
                memset(cmd, 0, BUF_SIZE);
                sprintf(cmd, "ls %s", file_path);
                fp = popen(cmd, "r");
                while (fgets(tmp, BUF_SIZE, fp)) {
                    write(clnt_sock, tmp, strlen(tmp));
                }
                pclose(fp);
            } else {
                sprintf(file_name, "%s/%s", file_path, buf);
                file_fd = open(file_name, O_RDONLY);
                if (file_fd == -1) {
                    write(clnt_sock, "File not found.\n", 16);
                } else {
                    while (1) {
                        memset(buf, 0, BUF_SIZE);
                        read_len = read(file_fd, buf, BUF_SIZE);
                        if (read_len == 0) {
                            break;
                        } else if (read_len == -1) {
                            error_handling("read() error");
                        }
                        write_len = write(clnt_sock, buf, read_len);
                        if (write_len == -1) {
                            error_handling("write() error");
                        }
                    }
                    close(file_fd);
                }
            }
        }
    }

    close(serv_sock);
    return 0;
}

void error_handling(char *message)
{
    fputs(message, stderr);
    fputc('\n', stderr);
    exit(1);
}

文件客户端代码：

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

#define BUF_SIZE 1024

void error_handling(char *message);

int main(int argc, char *argv[])
{
    int sock;
    struct sockaddr_in serv_addr;
    char buf[BUF_SIZE];
    char file_name[BUF_SIZE];
    int len, file_fd, read_len, write_len;
    FILE *fp;

    if (argc != 3) {
        printf("Usage: %s <IP> <port>\n", argv[0]);
        exit(1);
    }

    sock = socket(PF_INET, SOCK_STREAM, 0);
    if (sock == -1)
        error_handling("socket() error");

    memset(&serv_addr, 0, sizeof(serv_addr));
    serv_addr.sin_family = AF_INET;
    serv_addr.sin_addr.s_addr = inet_addr(argv[1]);
    serv_addr.sin_port = htons(atoi(argv[2]));

    if (connect(sock, (struct sockaddr*)&serv_addr, sizeof(serv_addr)) == -1)
        error_handling("connect() error");

    while (1) {
        printf("Enter command: ");
        fgets(buf, BUF_SIZE, stdin);
        if (buf[strlen(buf)-1] == '\n')
            buf[strlen(buf)-1] = '\0';

        if (strcmp(buf, "quit") == 0) {
            write(sock, buf, strlen(buf));
            break;
        } else if (strcmp(buf, "ls") == 0) {
            while (1) {
                memset(buf, 0, BUF_SIZE);
                len = read(sock, buf, BUF_SIZE);
                if (len == 0)
                    break;
                else if (len == -1)
                    error_handling("read() error");
                printf("%s", buf);
            }
        } else {
            write(sock, buf, strlen(buf));

            sprintf(file_name, "%s", buf);
            file_fd = open(file_name, O_WRONLY|O_CREAT, 0644);
            if (file_fd == -1)
                error_handling("open() error");

            while (1) {
                memset(buf, 0, BUF_SIZE);
                read_len = read(sock, buf, BUF_SIZE);
                if (read_len == 0)
                    break;
                else if (read_len == -1)
                    error_handling("read() error");
                write_len = write(file_fd, buf, read_len);
                if (write_len == -1)
                    error_handling("write() error");
            }
            close(file_fd);
        }
    }

    close(sock);
    return 0;
}

void error_handling(char *message)
{
    fputs(message, stderr);
    fputc('\n', stderr);
    exit(1);
}

这段代码中，文件服务器在指定的文件夹中查找文件并发送给客户端，客户端输入下载命令后会从服务器下载文件并保存在客户端当前目录中。注意，这段代码只是一个简单实现，实际应用中还需要对错误进行处理和安全性进行考虑。

用C语言实现利用TCP协议编写一个简单的文件服务器和客户端。 支持功能： 1. list：列表远端目录下的文件和目录信息（目录用方括号括起以示区分） 2. pwd: 查看远端当前目录 3. lpwd: 查看本地当前目录 4. cd xxxxx: 切换远端当前目录为xxxxx 5. lcd xxxxx: 切换本地当前目录为xxxxx 6. down xxxxx: 下载远端当前目录下的文件xxxxx到客户端的当前目录下 7. exit：断开连接并退出。

以下是一个简单的文件服务器和客户端的实现，使用TCP协议。

服务器端代码：

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

#define PORT 8080
#define MAX_CLIENTS 10
#define BUFFER_SIZE 1024

char current_dir[BUFFER_SIZE];

void list_files(int sock) {
    DIR *dir;
    struct dirent *ent;
    char buffer[BUFFER_SIZE];
    memset(buffer, 0, BUFFER_SIZE);
    dir = opendir(current_dir);
    if (dir != NULL) {
        while ((ent = readdir(dir)) != NULL) {
            if (ent->d_type == DT_DIR) {
                strcat(buffer, "[");
            }
            strcat(buffer, ent->d_name);
            if (ent->d_type == DT_DIR) {
                strcat(buffer, "]");
            }
            strcat(buffer, "\n");
        }
        closedir(dir);
    } else {
        strcpy(buffer, "Error: cannot open directory.\n");
    }
    send(sock, buffer, strlen(buffer), 0);
}

void get_pwd(int sock) {
    char buffer[BUFFER_SIZE];
    memset(buffer, 0, BUFFER_SIZE);
    getcwd(buffer, BUFFER_SIZE);
    strcat(buffer, "\n");
    send(sock, buffer, strlen(buffer), 0);
}

void change_dir(char *directory, int sock) {
    int result = chdir(directory);
    if (result == 0) {
        get_pwd(sock);
    } else {
        char buffer[BUFFER_SIZE];
        memset(buffer, 0, BUFFER_SIZE);
        strcpy(buffer, "Error: cannot change directory.\n");
        send(sock, buffer, strlen(buffer), 0);
    }
}

void download(char *filename, int sock) {
    char path[BUFFER_SIZE];
    memset(path, 0, BUFFER_SIZE);
    strcat(path, current_dir);
    strcat(path, "/");
    strcat(path, filename);
    int fd = open(path, O_RDONLY);
    if (fd == -1) {
        char buffer[BUFFER_SIZE];
        memset(buffer, 0, BUFFER_SIZE);
        strcpy(buffer, "Error: cannot open file.\n");
        send(sock, buffer, strlen(buffer), 0);
        return;
    }
    char buffer[BUFFER_SIZE];
    memset(buffer, 0, BUFFER_SIZE);
    int bytes_read;
    while ((bytes_read = read(fd, buffer, BUFFER_SIZE)) != 0) {
        send(sock, buffer, bytes_read, 0);
        memset(buffer, 0, BUFFER_SIZE);
    }
    close(fd);
}

int main() {
    int server_fd, client_fd, address_len;
    struct sockaddr_in server_addr, client_addr;
    char buffer[BUFFER_SIZE];

    // Create socket
    if ((server_fd = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
        perror("Error creating socket");
        exit(EXIT_FAILURE);
    }

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

    // Bind socket to address
    if (bind(server_fd, (struct sockaddr *)&server_addr, sizeof(server_addr)) == -1) {
        perror("Error binding socket");
        exit(EXIT_FAILURE);
    }

    // Listen for connections
    if (listen(server_fd, MAX_CLIENTS) == -1) {
        perror("Error listening for connections");
        exit(EXIT_FAILURE);
    }

    printf("Server listening on port %d...\n", PORT);

    while (1) {
        // Accept client connection
        address_len = sizeof(client_addr);
        if ((client_fd = accept(server_fd, (struct sockaddr *)&client_addr, &address_len)) == -1) {
            perror("Error accepting connection");
            continue;
        }

        printf("New client connected\n");

        // Send welcome message
        strcpy(buffer, "Welcome to the file server!\n");
        send(client_fd, buffer, strlen(buffer), 0);

        // Set current directory
        memset(current_dir, 0, BUFFER_SIZE);
        getcwd(current_dir, BUFFER_SIZE);

        while (1) {
            // Receive command from client
            memset(buffer, 0, BUFFER_SIZE);
            int bytes_received = recv(client_fd, buffer, BUFFER_SIZE, 0);
            if (bytes_received == -1) {
                perror("Error receiving data");
                break;
            } else if (bytes_received == 0) {
                printf("Client disconnected\n");
                break;
            }

            // Process command
            char *command = strtok(buffer, " ");
            char *argument = strtok(NULL, " ");
            if (strcmp(command, "list") == 0) {
                list_files(client_fd);
            } else if (strcmp(command, "pwd") == 0) {
                get_pwd(client_fd);
            } else if (strcmp(command, "cd") == 0) {
                if (argument == NULL) {
                    char buffer[BUFFER_SIZE];
                    memset(buffer, 0, BUFFER_SIZE);
                    strcpy(buffer, "Usage: cd directory\n");
                    send(client_fd, buffer, strlen(buffer), 0);
                    continue;
                }
                change_dir(argument, client_fd);
            } else if (strcmp(command, "down") == 0) {
                if (argument == NULL) {
                    char buffer[BUFFER_SIZE];
                    memset(buffer, 0, BUFFER_SIZE);
                    strcpy(buffer, "Usage: down filename\n");
                    send(client_fd, buffer, strlen(buffer), 0);
                    continue;
                }
                download(argument, client_fd);
            } else if (strcmp(command, "exit") == 0) {
                break;
            } else {
                char buffer[BUFFER_SIZE];
                memset(buffer, 0, BUFFER_SIZE);
                strcpy(buffer, "Invalid command\n");
                send(client_fd, buffer, strlen(buffer), 0);
            }
        }

        // Close client connection
        close(client_fd);
    }

    // Close server socket
    close(server_fd);

    return 0;
}

客户端代码：

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

#define SERVER_IP "127.0.0.1"
#define PORT 8080
#define BUFFER_SIZE 1024

void print_prompt() {
    char cwd[BUFFER_SIZE];
    memset(cwd, 0, BUFFER_SIZE);
    getcwd(cwd, BUFFER_SIZE);
    printf("%s> ", cwd);
    fflush(stdout);
}

void handle_list(int sock) {
    char buffer[BUFFER_SIZE];
    memset(buffer, 0, BUFFER_SIZE);
    int bytes_received;
    while ((bytes_received = recv(sock, buffer, BUFFER_SIZE, 0)) != 0) {
        printf("%s", buffer);
        memset(buffer, 0, BUFFER_SIZE);
    }
}

void handle_pwd(int sock) {
    char buffer[BUFFER_SIZE];
    memset(buffer, 0, BUFFER_SIZE);
    int bytes_received = recv(sock, buffer, BUFFER_SIZE, 0);
    if (bytes_received != -1) {
        printf("%s", buffer);
    }
}

void handle_cd(char *directory, int sock) {
    char buffer[BUFFER_SIZE];
    memset(buffer, 0, BUFFER_SIZE);
    sprintf(buffer, "cd %s", directory);
    send(sock, buffer, strlen(buffer), 0);
    int bytes_received = recv(sock, buffer, BUFFER_SIZE, 0);
    if (bytes_received != -1) {
        printf("%s", buffer);
    }
}

void handle_down(char *filename, int sock) {
    char buffer[BUFFER_SIZE];
    memset(buffer, 0, BUFFER_SIZE);
    sprintf(buffer, "down %s", filename);
    send(sock, buffer, strlen(buffer), 0);
    memset(buffer, 0, BUFFER_SIZE);
    int fd = open(filename, O_CREAT | O_WRONLY, S_IRUSR | S_IWUSR);
    int bytes_received;
    while ((bytes_received = recv(sock, buffer, BUFFER_SIZE, 0)) != 0) {
        write(fd, buffer, bytes_received);
        memset(buffer, 0, BUFFER_SIZE);
    }
    close(fd);
}

int main() {
    int sock;
    struct sockaddr_in server_addr;
    char buffer[BUFFER_SIZE];

    // Create socket
    if ((sock = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
        perror("Error creating socket");
        exit(EXIT_FAILURE);
    }

    // Set server address
    memset(&server_addr, 0, sizeof(server_addr));
    server_addr.sin_family = AF_INET;
    server_addr.sin_addr.s_addr = inet_addr(SERVER_IP);
    server_addr.sin_port = htons(PORT);

    // Connect to server
    if (connect(sock, (struct sockaddr *)&server_addr, sizeof(server_addr)) == -1) {
        perror("Error connecting to server");
        exit(EXIT_FAILURE);
    }

    // Receive welcome message
    int bytes_received = recv(sock, buffer, BUFFER_SIZE, 0);
    if (bytes_received != -1) {
        printf("%s", buffer);
    }

    while (1) {
        print_prompt();

        // Read command from user
        memset(buffer, 0, BUFFER_SIZE);
        fgets(buffer, BUFFER_SIZE, stdin);
        buffer[strlen(buffer) - 1] = '\0';

        // Process command
        char *command = strtok(buffer, " ");
        char *argument = strtok(NULL, " ");
        if (strcmp(command, "list") == 0) {
            send(sock, "list", strlen("list"), 0);
            handle_list(sock);
        } else if (strcmp(command, "pwd") == 0) {
            send(sock, "pwd", strlen("pwd"), 0);
            handle_pwd(sock);
        } else if (strcmp(command, "cd") == 0) {
            if (argument == NULL) {
                printf("Usage: cd directory\n");
                continue;
            }
            handle_cd(argument, sock);
        } else if (strcmp(command, "down") == 0) {
            if (argument == NULL) {
                printf("Usage: down filename\n");
                continue;
            }
            handle_down(argument, sock);
        } else if (strcmp(command, "lcd") == 0) {
            if (argument == NULL) {
                printf("Usage: lcd directory\n");
                continue;
            }
            int result = chdir(argument);
            if (result == -1) {
                printf("Error: cannot change directory.\n");
            }
        } else if (strcmp(command, "exit") == 0) {
            break;
        } else {
            printf("Invalid command\n");
        }
    }

    // Close socket
    close(sock);

    return 0;
}