为什么运行后会进入一下下然后闪退？

Question

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

int main(int argc, char *argv[])
{
    int serv_sock;
    int clnt_sock;

    int str_len;
    int client_count = 0;

    struct sockaddr_in serv_addr;
    struct sockaddr_in clnt_addr;
    socklen_t clnt_addr_size;

    char message[] = "Hello MUST! XueRenQianQian, 19098535i0110068";
    char message_from_client[50];
    char message_to_client[50];

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

    // new socket
    serv_sock = socket(AF_INET, SOCK_STREAM, 0);
    if (serv_sock == -1)
    {
        printf("socket error\n");
        exit(1);
    }

    printf("socket id is %d\n", serv_sock);

    memset(&serv_addr, 0, sizeof(serv_addr));
    serv_addr.sin_addr.s_addr = inet_addr("127.0.0.1");
    if (serv_addr.sin_addr.s_addr == INADDR_NONE)
    {
        printf("inet_aton error\n");
        exit(1);
    }
    serv_addr.sin_family = AF_INET;
    serv_addr.sin_port = htons(atoi(argv[1])); // port

    // bind addr/ip to socket
    if (bind(serv_sock, (struct sockaddr *)&serv_addr, sizeof(serv_addr)) == -1)
    {
        printf("bind() error");
        exit(1);
    }

    if (listen(serv_sock, 10) == -1)
    {
        printf("listen() error");
        exit(1);
    }

    while (client_count < 3)
    {
        clnt_addr_size = sizeof(clnt_addr);
        clnt_sock = accept(serv_sock, (struct sockaddr *)&clnt_addr, &clnt_addr_size);
        if (clnt_sock == -1)
        {
            printf("accept() error");
            continue;
        }
        // get clnt address
        char buff[INET_ADDRSTRLEN + 1] = {0}; // 不懂,查
        inet_ntop(AF_INET, &clnt_addr.sin_addr, buff, INET_ADDRSTRLEN);
        uint16_t port = ntohs(clnt_addr.sin_port);
        printf("connection from %s, port %d\n", buff, port);

        write(clnt_sock, message, sizeof(message));

        for (int i = 0; i < 5; i++)
        {
            memset(message_from_client, 0, sizeof(message_from_client)); // 修改后
            str_len = read(clnt_sock, message_from_client, sizeof(message_from_client) - 1);
            message_from_client[str_len] = '\0';
            if (str_len == -1)
            {
                printf("read() error!");
                exit(1);
            }

            printf("Message from the client: %s \n", message_from_client);
            if (strlen(message_from_client) == 1 && (message_from_client[0] == 'Q' || message_from_client[0] == 'q'))
                break;

            printf("Send message: ");
            scanf("%[^\n]", message_to_client);
            getchar();
            write(clnt_sock, message_to_client, strlen(message_to_client));
            if (strlen(message_to_client) == 1 && (message_to_client[0] == 'Q' || message_to_client[0] == 'q'))
                break;
        }

        close(clnt_sock);
        client_count++;
    }

    close(serv_sock);

    return 0;
}

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

int main(int argc, char *argv[])
{
    int sock;
    struct sockaddr_in serv_addr;
    char message[50];
    char message_to_server[50];
    char message_from_server[50];
    int str_len;

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

    sock = socket(PF_INET, SOCK_STREAM, 0);
    if (sock == -1)
    {
        printf("socket() error");
        exit(1);
    }

    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)
    {
        printf("Connect() error!");
        exit(1);
    }
    str_len = read(sock, message, sizeof(message) - 1);

    if (str_len == -1)
    {
        printf("read() error!");
        exit(1);
    }

    printf("From server: %s \n", message);

    for (int i = 0; i < 5; i++)
    {
        printf("Type the message to server:");
        scanf("%[^\n]", message_to_server);
        getchar();
        write(sock, message_to_server, strlen(message_to_server));
        if (strlen(message_to_server) == 1 && (message_to_server[0] == 'Q' || message_to_server[0] == 'q'))
            break;

        memset(message_from_server, 0, sizeof(message_from_server)); // 修改后
        str_len = read(sock, message_from_server, sizeof(message_from_server) - 1);
        message_from_server[str_len] = '\0';

        if (str_len == -1)
        {
            printf("read() error!");
            exit(1);
        }
        printf("Message from the server: %s \n", message_from_server);
        if (strlen(message_from_server) == 1 && (message_from_server[0] == 'Q' || message_from_server[0] == 'q'))
            break;
    }

    close(sock);
    return 0;
}

```

Answer 1

【以下回答由 GPT 生成】

这段代码可能会出现闪退的情况是因为在bind函数调用之前没有检查socket函数是否成功创建了新的套接字。如果socket函数创建失败，会返回-1，这会导致bind函数失败并引发闪退。

为了解决这个问题，可以在socket函数调用后添加错误检查，并在创建socket失败时进行适当的错误处理。以下是更新后的代码片段：

// Create a new socket
serv_sock = socket(AF_INET, SOCK_STREAM, 0);
if (serv_sock == -1)
{
    printf("socket error\n");
    exit(1);
}

// Check if socket creation is successful
if (serv_sock == -1)
{
    perror("socket creation failed");
    exit(EXIT_FAILURE);
}

printf("socket id is %d\n", serv_sock);

通过在socket函数调用之后添加错误检查，并在创建套接字失败时打印错误消息，可以帮助定位问题并进行适当的修复。

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