hpcore/src/comm/comm_client.cpp

#include "comm_client.hpp"
#include "comm_session.hpp"
#include "comm_session_handler.hpp"
#include "../hplog.hpp"
#include "../util.hpp"

namespace comm
{

int comm_client::start(std::string_view host, const uint16_t port, const uint64_t (&metric_thresholds)[4], const uint64_t max_msg_size)
{
    return start_websocat_process(host, port);
}

void comm_client::stop()
{
    if (read_fd > 0)
        close(read_fd);
    if (write_fd > 0)
        close(write_fd);

    if (websocat_pid > 0)
        kill(websocat_pid, SIGINT); // Kill websocat.
}

int comm_client::start_websocat_process(std::string_view host, const uint16_t port)
{
    // setup pipe I/O
    if (pipe(read_pipe) < 0 || pipe(write_pipe) < 0)
    {
        LOG_ERR << errno << ": websocat pipe creation failed.";
        return -1;
    }

    const pid_t pid = fork();

    if (pid > 0)
    {
        // HotPocket process.
        websocat_pid = pid;

        read_fd = read_pipe[0];
        write_fd = write_pipe[1];

        // Close unused fds by us.
        close(write_pipe[0]);
        close(read_pipe[1]);

        // Wait for some time and check if websocat is still running properly.
        util::sleep(20);
        int pid_status;
        waitpid(websocat_pid, &pid_status, WNOHANG);
        if (WIFEXITED(pid_status)) // This means websocat has exited.
        {
            close(read_fd);
            close(write_fd);
            return -1;
        }
    }
    else if (pid == 0)
    {
        // Websocat process.
        close(write_pipe[1]); //parent write
        close(read_pipe[0]);  //parent read

        dup2(write_pipe[0], STDIN_FILENO); //child read
        close(write_pipe[0]);
        dup2(read_pipe[1], STDOUT_FILENO); //child write
        close(read_pipe[1]);

        std::string url = std::string("wss://").append(host).append(":").append(std::to_string(port));

        // Fill process args.
        char *execv_args[] = {
            conf::ctx.websocat_exe_path.data(),
            url.data(),
            (char *)"-k", // Accept invalid certificates
            (char *)"-b", // Binary mode
            (char *)"-E", // Close on EOF
            (char *)"-q", // Quiet mode
            NULL};

        const int ret = execv(execv_args[0], execv_args);
        LOG_ERR << errno << ": websocat process execv failed.";
        exit(1);
    }
    else
    {
        LOG_ERR << "fork() failed when starting websocat process.";
        return -1;
    }

    return 0;
}

} // namespace comm