softwarecontainer::FileToolkitWithUndo Class Reference

Inheritance diagram for softwarecontainer::FileToolkitWithUndo:

Public Member Functions
bool	bindMount (const std::string &src, const std::string &dst, const std::string &tmpContainerRoot, bool readOnly, bool writeBufferEnabled=false)
	bindMount Bind mount a src directory to another position dst. More...
bool	tmpfsMount (const std::string dst, const int maxSize)
	tmpfsMount Mount a tmpfs in the dst path and limit size of the tmpfs to maxSize More...

Protected Member Functions
bool	writeToFile (const std::string &path, const std::string &content)
void	markFileForDeletion (const std::string &path)
bool	overlayMount (const std::string &lower, const std::string &upper, const std::string &work, const std::string &dst)
	overlayMount Mount a directory with an overlay on top of it. More...
bool	syncOverlayMount (const std::string &lower, const std::string &upper)
	syncOverlayMount Copy the directory structure from upper layer to the lower layer More...
bool	createSharedMountPoint (const std::string &path)
	createSharedMountPoint Make the mount point shared, ie new mount points created in one bind mount will also be created in the other mount point. More...
bool	pathInList (const std::string path)
	checks whether given path is already added to clean up handlers or not More...

Protected Attributes
std::vector< std::unique_ptr< CleanUpHandler > >	m_cleanupHandlers
	m_cleanupHandlers A vector of cleanupHandlers added during the lifetime of the FileToolKitWithUndo that will be run from the destructor. More...
std::vector< std::unique_ptr< CreateDir > >	m_createDirList
	m_createDirList A vector of CreateDir classes. More...

Detailed Description

Definition at line 28 of file filetoolkitwithundo.h.

Member Function Documentation

bool softwarecontainer::FileToolkitWithUndo::bindMount	(	const std::string &	src,
		const std::string &	dst,
		const std::string &	tmpContainerRoot,
		bool	readOnly,
		bool	writeBufferEnabled = false
	)

bindMount Bind mount a src directory to another position dst.

Parameters

src	Path to mount from
dst	Path to mount to
readOnly	Make the bind mount destination read only
writeBufferEnabled	Enable write buffers on the bind mount.

Returns

true on success, false on failure

Definition at line 53 of file filetoolkitwithundo.cpp.

References softwarecontainer::existsInFileSystem(), softwarecontainer::isDirectory(), and m_createDirList.

Referenced by softwarecontainer::Container::bindMountInContainer().

{
    unsigned long flags =  0;
    std::string fstype;
    int mountRes;
    std::unique_ptr<CreateDir> createDirInstance = std::unique_ptr<CreateDir>(new CreateDir());

    if (!existsInFileSystem(src)) {
        log_error() << src << " does not exist on the host, can not bindMount";
        return false;
    }

    if (!existsInFileSystem(dst)) {
        log_error() << dst << " does not exist on the host, can not bindMount";
        return false;
    }

    log_debug() << "Bind-mounting " << src << " in " << dst << ", flags: " << flags;

    if(writeBufferEnabled && isDirectory(src)) {
        std::string upperDir , workDir;

        // In case the tmpContainerRoot is set to nothing we need to create a
        // good bindmount directory.
        if (tmpContainerRoot == "") {
            upperDir = createDirInstance->createTempDirectoryFromTemplate("/tmp/sc-bindmount-upper-XXXXXX");
            workDir = createDirInstance->createTempDirectoryFromTemplate("/tmp/sc-bindmount-work-XXXXXX");
        } else {
            upperDir = createDirInstance->createTempDirectoryFromTemplate(tmpContainerRoot + "/bindmount-upper-XXXXXX");
            workDir = createDirInstance->createTempDirectoryFromTemplate(tmpContainerRoot + "/bindmount-work-XXXXXX");
        }
        fstype.assign("overlay");

        std::ostringstream os;
        os << "lowerdir=" << src << ",upperdir=" << upperDir << ",workdir=" << workDir;

        log_debug() << "writeBufferEnabled, config: " << os.str();

        mountRes = mount("overlay", dst.c_str(), fstype.c_str(), flags, os.str().c_str());
        log_debug() << "mountRes: " << mountRes;
    } else {
        const void *data = nullptr;
        flags = MS_BIND;
        mountRes = mount(src.c_str(), dst.c_str(), fstype.c_str(), flags, data);
    }

    if (mountRes == 0) {
        log_verbose() << "Bind-mounted folder " << src << " in " << dst;
    } else {
        log_error() << "Could not mount into container: src=" << src
                    << " , dst=" << dst << " err=" << strerror(errno);
        return false;
    }

    if (readOnly && !writeBufferEnabled) {
        const void *data = nullptr;

        flags = MS_REMOUNT | MS_RDONLY | MS_BIND;

        log_debug() << "Re-mounting read-only" << src << " in "
                    << dst << ", flags: " << flags;
        mountRes = mount(src.c_str(), dst.c_str(), fstype.c_str(), flags, data);
        if (mountRes != 0) {
            // Failure
            log_error() << "Could not re-mount " << src << " , read-only on "
                        << dst << " err=" << strerror(errno);
            return false;
        }
    }
    m_createDirList.push_back(std::move(createDirInstance));
    return true;
}

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bool softwarecontainer::FileToolkitWithUndo::tmpfsMount	(	const std::string	dst,
		const int	maxSize
	)

tmpfsMount Mount a tmpfs in the dst path and limit size of the tmpfs to maxSize

Parameters

dst	The destination to mount a tmpfs on
maxSize	The max size of the tmpfs being mounted

Returns

Definition at line 177 of file filetoolkitwithundo.cpp.

References softwarecontainer::isDirectoryEmpty(), m_cleanupHandlers, and m_createDirList.

Referenced by softwarecontainer::SoftwareContainer::SoftwareContainer().

{
    std::string fstype = "tmpfs";
    unsigned long flags = 0;
    std::unique_ptr<CreateDir> createDirInstance = std::unique_ptr<CreateDir>(new CreateDir());

    if (!createDirInstance->createDirectory(dst)) {
        log_error() << "Failed to create " << dst << " directory for tmpfs mount";
        return false;
    }

    std::string mountoptions = logging::StringBuilder() << "size=" << maxSize;

    bool directoryIsEmpty = isDirectoryEmpty(dst);

    int mountRes = mount("tmpfs", dst.c_str(), fstype.c_str(), flags, mountoptions.c_str());

    if (0 == mountRes) {
        log_verbose() << "tmpfs mounted in " << dst;
        m_cleanupHandlers.emplace_back(new MountCleanUpHandler(dst));
    } else {
        log_error() << "Could not mount tmpfs into directory: " << dst << " size=" << maxSize;
        return false;
    }

    m_createDirList.push_back(std::move(createDirInstance));
    return true;
}

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bool softwarecontainer::FileToolkitWithUndo::overlayMount ( const std::string &  lower, const std::string &  upper, const std::string &  work, const std::string &  dst  )

protected

overlayMount Mount a directory with an overlay on top of it.

An overlay protects the lower filesystem from writes by writing to the upper file system through the work directory.

Parameters

lower	The lower file system, this will be read only.
upper	The upper file system, this can be a tmpfs/ramfs of some kind. This is where final writes wind up
work	This is a work directory, preferably a tmpfs/ramfs of some kind. This is where writes wind up temporarily.
dst	Where the overlay filesystem will be mounted.

Returns

true on success, false on failure

Definition at line 130 of file filetoolkitwithundo.cpp.

References m_cleanupHandlers, and m_createDirList.

Referenced by softwarecontainer::Container::create().

{
    std::string fstype = "overlay";
    unsigned long flags = 0;
    std::unique_ptr<CreateDir> createDirInstance = std::unique_ptr<CreateDir>(new CreateDir());

    if (!createDirInstance->createDirectory(lower)
        || !createDirInstance->createDirectory(upper)
        || !createDirInstance->createDirectory(work)
        || !createDirInstance->createDirectory(dst))
    {
        log_error() << "Failed to create lower/upper/work directory for overlayMount. lowerdir=" <<
                       lower << ", upperdir=" << upper << ", workdir=" << work;
        return false;
    }

    std::string mountoptions = logging::StringBuilder() << "lowerdir=" << lower
                                                        << ",upperdir=" << upper
                                                        << ",workdir=" << work;

    int mountRes = mount("overlay", dst.c_str(), fstype.c_str(), flags, mountoptions.c_str());

    if (mountRes == 0) {
        log_verbose() << "overlayMounted folder " << lower << " in " << dst;
        m_cleanupHandlers.emplace_back(new MountCleanUpHandler(dst));
        m_cleanupHandlers.emplace_back(new OverlaySyncCleanupHandler(upper, lower));
    } else {
        log_error() << "Could not mount into container: upper=" << upper
                    << ",lower=" << lower
                    << ",work=" << work
                    << " at dst=" << dst << " err=" << strerror(errno);
        return false;
    }

    m_createDirList.push_back(std::move(createDirInstance));
    return true;
}

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bool softwarecontainer::FileToolkitWithUndo::syncOverlayMount ( const std::string &  lower, const std::string &  upper  )

protected

syncOverlayMount Copy the directory structure from upper layer to the lower layer

Parameters

lower	The lower layer used in an overlay file system.
upper	The upper layer in an overlay file system.

Returns

true on success, false on failure

Definition at line 171 of file filetoolkitwithundo.cpp.

References softwarecontainer::RecursiveCopy::copy(), and softwarecontainer::RecursiveCopy::getInstance().

{
    return RecursiveCopy::getInstance().copy(upper, lower);
}

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bool softwarecontainer::FileToolkitWithUndo::createSharedMountPoint ( const std::string &  path )

protected

createSharedMountPoint Make the mount point shared, ie new mount points created in one bind mount will also be created in the other mount point.

Parameters

path	The mount path to make shared.

Returns

true on success, false on failure

Definition at line 206 of file filetoolkitwithundo.cpp.

References m_cleanupHandlers.

Referenced by softwarecontainer::Container::initialize().

{
    auto mountRes = mount(path.c_str(), path.c_str(), "", MS_BIND, nullptr);
    if (mountRes != 0) {
        log_error() << "Could not bind mount " << path << " to itself";
        return false;
    }

    mountRes = mount(path.c_str(), path.c_str(), "", MS_UNBINDABLE, nullptr);
    if (mountRes != 0) {
        log_error() << "Could not make " << path << " unbindable";
        return false;
    }

    mountRes = mount(path.c_str(), path.c_str(), "", MS_SHARED, nullptr);
    if (mountRes != 0) {
        log_error() << "Could not make " << path << " shared";
        return false;
    }

    m_cleanupHandlers.emplace_back(new MountCleanUpHandler(path));
    log_debug() << "Created shared mount point at " << path;

    return true;
}

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bool softwarecontainer::FileToolkitWithUndo::pathInList ( const std::string  path )

protected

checks whether given path is already added to clean up handlers or not

This function will be called only before adding new CleanUpHandler for FileCleanUpHandler and DirectoryCleanUpHandler. The reason behind this, only indicated CleanUpHandlers are related with file/directory removal operations.

Parameters

a	string path name to check

Returns

true if the path is already exist, false otherwise

Definition at line 232 of file filetoolkitwithundo.cpp.

References m_cleanupHandlers.

Referenced by softwarecontainer::Container::bindMountInContainer().

{

    for (auto &element : m_cleanupHandlers) {
        if (element->queryName() == path) {
            return true;
        }
    }
    return false;
}

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Field Documentation

std::vector<std::unique_ptr<CleanUpHandler> > softwarecontainer::FileToolkitWithUndo::m_cleanupHandlers

protected

m_cleanupHandlers A vector of cleanupHandlers added during the lifetime of the FileToolKitWithUndo that will be run from the destructor.

Definition at line 121 of file filetoolkitwithundo.h.

Referenced by softwarecontainer::Container::bindMountInContainer(), createSharedMountPoint(), overlayMount(), pathInList(), and tmpfsMount().

std::vector<std::unique_ptr<CreateDir> > softwarecontainer::FileToolkitWithUndo::m_createDirList

protected

m_createDirList A vector of CreateDir classes.

This class handles directory cleaning operations when either interfered errors or when its destructor runs.

Definition at line 127 of file filetoolkitwithundo.h.

Referenced by bindMount(), softwarecontainer::Container::bindMountInContainer(), softwarecontainer::Container::initialize(), overlayMount(), softwarecontainer::SoftwareContainer::previouslyConfigured(), and tmpfsMount().

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The documentation for this class was generated from the following files:

• common/filetoolkitwithundo.h
• common/filetoolkitwithundo.cpp