无法使用mysql udf通过套接字将字符串发送到服务器

Question

在mysql shell上，我正在运行＆＃34; SELECT socketCall（）;＆＃34;返回5.

我正在尝试从mysql中的UDF函数连接到unix套接字服务器（本地运行）。 UDF函数中使用的connect（）函数以某种方式失败，并立即从那里返回。

请帮我找出我在代码中做错了什么。我正在研究树莓派。

UDF功能代码如下：

#define SOCK_PATH "/root/mysock"

longlong socketCall(UDF_INIT *initid, UDF_ARGS *args, char *is_null, char *error)
{
    int s,len,n;
    struct sockaddr_un remote;
    char str[100] = "Hello Saggu calling from MySql";

    if ((s = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) {
        return 2;  
    }
    bzero((char *) &remote, sizeof(remote));
    remote.sun_family = AF_UNIX;
    strcpy(remote.sun_path, SOCK_PATH);
    len = strlen(remote.sun_path) + sizeof(remote.sun_family);
    if (connect(s, (struct sockaddr *)&remote, len) == -1) {
        return 5;
    }

    n = send(s, str, strlen(str), 0);
    close(s);
    return n;    
}    

服务器代码如下：

#define SOCK_PATH "/root/mysock"
int main(void)
{
    int s, s2, t, len;
    struct sockaddr_un local, remote;
    char str[100];
    if ((s = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) {
        perror("socket");
        exit(1);
    }
    local.sun_family = AF_UNIX;
    strcpy(local.sun_path, SOCK_PATH);
    unlink(local.sun_path);
    len = strlen(local.sun_path) + sizeof(local.sun_family);
    if (bind(s, (struct sockaddr *)&local, len) == -1) {
       perror("bind");
       exit(1);
    }
    if (listen(s, 5) == -1) {
       perror("listen");
       exit(1);
    }
    for(;;) {
        int done, n;
        printf("Waiting for a connection...\n");
        t = sizeof(remote);
        if ((s2 = accept(s, (struct sockaddr *)&remote, &t)) == -1) {
            perror("accept");
            exit(1);
        }
        printf("Connected.\n");
        n = recv(s2, str, 100, 0);
        printf("\n  %s\n",str);      
        close(s2);
    }    
    return 0;    
}