container.h

/*
 * Copyright (C) 2016-2017 Pelagicore AB
 *
 * Permission to use, copy, modify, and/or distribute this software for
 * any purpose with or without fee is hereby granted, provided that the
 * above copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL
 * WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR
 * BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES
 * OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
 * WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
 * ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
 * SOFTWARE.
 *
 * For further information see LICENSE
 */

#pragma once

#include <string>
#include <vector>

#include <lxc/lxccontainer.h>

#include "filetoolkitwithundo.h"

#include "softwarecontainer-common.h"
#include "containerabstractinterface.h"

namespace softwarecontainer {

class Container :
    private FileToolkitWithUndo, public ContainerAbstractInterface
{
    LOG_DECLARE_CLASS_CONTEXT("CONT", "Container");

    static constexpr const char *GATEWAYS_PATH = "/gateways";

    enum class LXCContainerState
    {
        STOPPED, STARTING, RUNNING, STOPPING, ABORTING, FREEZING, FROZEN, THAWED, ELEMENT_COUNT
    };

    static const char *toString(LXCContainerState state)
    {
        return s_LXCContainerStates[static_cast<int>(state)];
    }

    static std::vector<const char *> s_LXCContainerStates;
    static const char *s_LXCRoot;

    static void init_lxc();

public:

    Container(const std::string id,
              const std::string &configFile,
              const std::string &containerRoot,
              bool writeBufferEnabled = false,
              int shutdownTimeout = 1);

    ~Container();

    bool create();

    bool start(pid_t *pid);

    bool setCgroupItem(std::string subsys, std::string value);

    bool execute(const std::string &commandLine,
                 pid_t *pid,
                 const EnvironmentVariables &variables,
                 const std::string &workingDirectory = "/",
                 int stdin = -1,
                 int stdout = 1,
                 int stderr = 2);

    /*
     * @brief Start a function inside the container.
     *
     * The function executes as a separate process.
     */
    bool execute(ExecFunction function,
                 pid_t *pid,
                 const EnvironmentVariables &variables = EnvironmentVariables(),
                 int stdin = -1,
                 int stdout = 1,
                 int stderr = 2);

    bool executeSync(ExecFunction function,
                     pid_t *pid,
                     const EnvironmentVariables &variables = EnvironmentVariables(),
                     int stdin = -1,
                     int stdout = 1,
                     int stderr = 2);

    bool bindMountInContainer(const std::string &pathInHost,
                              const std::string &pathInContainer,
                              bool readOnly = true);


    bool mountDevice(const std::string &pathInHost);

    bool destroy();
    bool destroy(unsigned int timeout);

    bool shutdown();
    bool shutdown(unsigned int timeout);

    /*
     * @brief calls freeze() on the LXC container
     *
     * This only works if the container is currently running and is not already
     * suspended.
     *
     * @return true if the container was successfully suspended
     * @return false otherwise
     */
    bool suspend();

    /*
     * @brief calls unfreeze() on the LXC container
     *
     * This only works if the container was already suspended. This sets the container
     * into running state again.
     *
     * @return true if the container was successfully resumed
     * @return false otherwise
     */
    bool resume();

    bool stop();

    bool waitForState(LXCContainerState state, int timeout = 20);
    bool ensureContainerRunning();

    bool initialize();

    std::string toString();

    const char *id() const;
    std::string gatewaysDirInContainer() const;
    std::string gatewaysDir() const;

    bool setEnvironmentVariable(const std::string &var, const std::string &val);

private:
    static int unlimitCoreDump();

    static int executeInContainerEntryFunction(void *param);

    bool bindMountCore(const std::string &pathInHost,
                       const std::string &pathInContainer,
                       const std::string &tempDir,
                       bool readonly);

    bool remountReadOnlyInContainer(const std::string &path);

    bool rollbackCreate();

    std::string m_configFile;

    const std::string m_id;

    std::string m_rootFSPath;

    struct lxc_container *m_container = nullptr;

    std::string m_containerRoot;

    bool m_writeBufferEnabled;

    // All environment variables set by gateways
    EnvironmentVariables m_gatewayEnvironmentVariables;

    int m_shutdownTimeout = 1;

    enum class ContainerState : unsigned int {
        DEFAULT = 0,
        PREPARED = 1,
        DESTROYED = 2,
        CREATED = 3,
        STARTED = 4,
        FROZEN = 5,
    };
    ContainerState m_state = ContainerState::DEFAULT;
};

} // namespace softwarecontainer