qshell.cpp

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/**
 * @file qshell.cpp
 * Send shell commands to qurt
 *
 * @author Nicolas de Palezieux <ndepal@gmail.com>
 */

#include <px4_platform_common/log.h>
#include <unistd.h>
#include <stdio.h>
#include <string.h>
#include <string>
#include <stdlib.h>
#include <drivers/drv_hrt.h>
#include <uORB/topics/qshell_retval.h>

#include "qshell.h"

px4::AppState QShell::appState;

orb_advert_t QShell::_pub_qshell_req = nullptr;
int QShell::_sub_qshell_retval = -1;
uint32_t QShell::_current_sequence = 0;

int QShell::main(std::vector<std::string> argList)
{
    int ret = _send_cmd(argList);

    if (ret != 0) {
        PX4_ERR("Could not send command");
        return -1;
    }

    ret = _wait_for_retval();

    if (ret != 0) {
        PX4_ERR("Could not get return value");
        return -1;
    }

    return 0;
}

int QShell::_send_cmd(std::vector<std::string> &argList)
{
    // Let's use a sequence number to check if a return value belongs to the
    // command that we just sent and not a previous one that we assumed that
    // it had timed out.
    ++_current_sequence;

    struct qshell_req_s qshell_req;
    std::string cmd;

    for (size_t i = 0; i < argList.size(); i++) {
        cmd += argList[i];

        if (i < argList.size() - 1) {
            cmd += " ";
        }
    }

    if (cmd.size() >= qshell_req.MAX_STRLEN) {
        PX4_ERR("Command too long: %d >= %d", (int) cmd.size(), (int) qshell_req.MAX_STRLEN);
        return -1;
    }

    PX4_INFO("Send cmd: '%s'", cmd.c_str());

    qshell_req.strlen = cmd.size();
    strcpy((char *)qshell_req.cmd, cmd.c_str());
    qshell_req.request_sequence = _current_sequence;

    int instance;
    orb_publish_auto(ORB_ID(qshell_req), &_pub_qshell_req, &qshell_req, &instance, ORB_PRIO_DEFAULT);

    return 0;
}

int QShell::_wait_for_retval()
{
    if (_sub_qshell_retval < 0) {
        _sub_qshell_retval = orb_subscribe(ORB_ID(qshell_retval));

        if (_sub_qshell_retval < 0) {
            PX4_ERR("could not subscribe to retval");
            return -1;
        }
    }

    const hrt_abstime time_started_us = hrt_absolute_time();

    while (hrt_elapsed_time(&time_started_us) < 3000000) {
        bool updated;
        orb_check(_sub_qshell_retval, &updated);

        if (updated) {

            struct qshell_retval_s retval;
            orb_copy(ORB_ID(qshell_retval), _sub_qshell_retval, &retval);

            if (retval.return_sequence != _current_sequence) {
                PX4_WARN("Ignoring return value with wrong sequence");

            } else {
                if (retval.return_value) {
                    PX4_WARN("cmd returned with: %d", retval.return_value);
                }

                return 0;
            }
        }

        usleep(1000);
    }

    PX4_ERR("command timed out");
    return -1;
}