C套接字HTTP请求异步打印响应，当没有显式命令这样做时

Question

我现在正试着通过编写一个简单的web抓取器来学习C套接字，但是我自己做套接字编程和HTTP请求，目前使用的是套接字库。我已经编写了一个函数，它成功地向http://mirror.vcu.edu发送了一个非SSL请求，并将输出存储在一个名为response的变量中。

char *noSSLRequest(REQUEST_HEADER_INFO *request_header_info) {
    struct sockaddr_in serverAddress;
    char *requestHeader;
    unsigned short serverPort;
    char serverIP[13];
    domainToIP(request_header_info->host, serverIP);
    char *response = calloc(0, 0);
    ssize_t bytesReceived = 0;


    int sockFD; //Only supporting IPV4 right now, returns file descriptor for socket

    if ((sockFD = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP)) < -1) {
        freeRequestHeaderInfo(request_header_info);
        fprintf(stderr, "Error, could not open socket in http.c getHTMLBody(). Reason for error %s", strerror(errno));
        exit(-1);
    }
    printf(ANSI_COLOR_GREEN "LOG: Socket file descriptor is %d" ANSI_COLOR_RESET, sockFD);
    serverPort = 80;
    memset(&serverAddress, 0, sizeof(serverAddress));
    serverAddress.sin_family = AF_INET;
    serverAddress.sin_port = htons(80);
    inet_aton(serverIP, &serverAddress.sin_addr);

    if (connect(sockFD, (const struct sockaddr *) &serverAddress, sizeof(serverAddress)) < 0) {
        freeRequestHeaderInfo(request_header_info);
        fprintf(stderr, "Error, could not connect socket in http.c getHTMLBody(). Reason for error %s",
                strerror(errno));
        exit(-1);
    }

    printf(ANSI_COLOR_GREEN "\nLOG: Connected socket at descriptor %d to IP %s and port %d" ANSI_COLOR_RESET, sockFD,
           serverIP, serverPort);

    requestHeader = craftRequestHeader(request_header_info);

    if (send(sockFD, requestHeader, strlen(requestHeader), 0) < 0) {
        freeRequestHeaderInfo(request_header_info);
        fprintf(stderr, "Error, could not send request. Reason for error %s",
                strerror(errno));
        exit(-1);
    }

    printf(ANSI_COLOR_GREEN "\nLOG: Sent HTTP request from socket at descriptor %d to IP %s and port %d." ANSI_COLOR_RESET,
           sockFD,
           serverIP, serverPort);


    free(requestHeader);
    printf(ANSI_COLOR_GREEN "\nLOG: Starting receive operation" ANSI_COLOR_RESET);
    ssize_t bytesReceivedPrevious = -1;
    char buffer[RESPONSE_BUFFER_SIZE];


    while (bytesReceived < (RESPONSE_MAX_LEN * sizeof(char)) && bytesReceived > bytesReceivedPrevious) {
        bytesReceivedPrevious = bytesReceived;
        bytesReceived = recv(sockFD, buffer, RESPONSE_BUFFER_SIZE, 0);
        response = realloc(response, sizeof(*response) + RESPONSE_BUFFER_SIZE);
        strcat(response, buffer); //Append to the end, safe because recv takes care of limiting buffer size
    }
    response = realloc(response, sizeof(*response) + sizeof(char));
    response[strlen(response)] = '\0';
    printf(ANSI_COLOR_GREEN "\nLOG: Received HTTP response from socket at descriptor %d to IP %s and port %d.\n\n\n\n\n" ANSI_COLOR_RESET,
           sockFD,
           serverIP, serverPort);
    if (close(sockFD) < 0) {
        freeRequestHeaderInfo(request_header_info);
        fprintf(stderr, "Error, could not close socket in http.c getHTMLBody(). Reason for error %s", strerror(errno));
        exit(-1);
    }
    printf(ANSI_COLOR_GREEN "\nLOG: Closed socket at descriptor %d" ANSI_COLOR_RESET, sockFD);
    freeRequestHeaderInfo(request_header_info);

    return response;
}

一切正常，response有一个空的结束符，生活很好，除了在我的控制台中，出于某种原因，我打印出了response的输出。我感觉好像有什么东西在泄漏，因为这个输出也是绿色的，即使在每次日志之后，我都会将颜色重置为默认值。我知道上面的一些标志和其他东西没有显示出来，我无法在这里获得所有的信息和代码，所以我有一个github repo和更详细的issue。

日志的图片在这里和这个问题上，尽管我不能得到完整的输出，所以非彩色文本版本在这个问题上。

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Answer 1

这段代码

response = realloc(response, sizeof(response) + RESPONSE_BUFFER_SIZE);

这段代码

response = realloc(response, sizeof(response) + sizeof(char));

两者都会导致未定义的行为。

response是一个char * -a指针。sizeof() a pointer是指针的大小，而不是它指向的字符串的长度。

还要注意的是，根据定义，sizeof(char)是一个。