突破NAMESPACE隔离与Docker容器内JVM交互

参考jattach，会进入目标命名空间

//进入指定文件描述符fd的命名空间
int enter_ns(int pid, const char* type) {
#ifdef __NR_setns
    char path[64], selfpath[64];
    snprintf(path, sizeof(path), "/proc/%d/ns/%s", pid, type);
    snprintf(selfpath, sizeof(selfpath), "/proc/self/ns/%s", type);

    fprintf(stdout, "path is %s \n", path);                //proc/10647/ns/net
    fprintf(stdout, "selfpath is %s\n", selfpath);         ///proc/self/ns/net

    //获得
    struct stat oldns_stat, newns_stat;
    if (stat(selfpath, &oldns_stat) == 0 && stat(path, &newns_stat) == 0) {
        // Don't try to call setns() if we're in the same namespace already
        if (oldns_stat.st_ino != newns_stat.st_ino) {
            int newn