Help functions for Storage related things. More...

#include <StorageHelper.h>

Static Public Member Functions
static int	loopDeviceAssociate (int fileFd, std::string *loopDevPath)
	Associates a give file descriptor with a loop device.

static int	openLoopDevice (std::string *loopDevice)
	Attempts to open an available loop device.

static bool	attachFileToLoopDevice (int loopFd, int fileFd)
	Attempts to attach the file to the loop device.

static int	attachLoopDevice (const std::string &sourceFile, std::string *loopDevice)
	Attaches the given file to an available loop device.

static bool	createFileIfNeeded (const std::string &filePath, const size_t storageSize, const uid_t userId, const std::string &fileSystem)
	Checks if file exists, if yes return true, if not try to create it. If success return true, if file don't exist and cannot be created return false.

static void	cleanMountLostAndFound (const std::string &mountPoint, const std::string &logTag)
	Logs and deletes any files found in the lost+found directory of the mount point.

static std::string	getLoopDevice (const std::string &backingFile)
	Get the loop device for a given backing file.

static int	getMountOptions (const std::list< std::string > &mountOptions)

static bool	rmdirRecursive (int dirFd, const std::string &path)
	Removes a directory and all it's contents.

static bool	rmdirContents (int dirFd, const std::string &path)
	Removes the contents of a directory but leave the actual directory in place.

static bool	deleteRecursive (int dirfd, int depth)
	Recursive function that deletes everything within the supplied directory (as a descriptor).

Detailed Description

Help functions for Storage related things.

All low level help functions that doesn't rely on current state

Member Function Documentation

◆ attachFileToLoopDevice()

bool StorageHelper::attachFileToLoopDevice	(	int	loopFd,
		int	fileFd
	)

static

Attempts to attach the file to the loop device.

Parameters

[in]	loopFd	An open file descriptor to the loop device
[in]	fileFd	An open file descriptor that should be associate with the loop device.

Returns: on success a positive file desccriptor corresponding to a free loop device, -1 on error.

◆ attachLoopDevice()

int StorageHelper::attachLoopDevice	(	const std::string &	sourceFile,
		std::string *	loopDevice
	)

static

Attaches the given file to an available loop device.

Parameters

[in]	sourceFile	The path to the image file.
[out]	loopDevice	The path to the loop device that was attached.

Returns: the file descriptor to the loop device if attached, otherwise -1.

◆ cleanMountLostAndFound()

void StorageHelper::cleanMountLostAndFound	(	const std::string &	mountPoint,
		const std::string &	logTag
	)

static

Logs and deletes any files found in the lost+found directory of the mount point.

We should be clearing the lost+found to avoid cruft building up and taking all the space in the loop mount.

Parameters

[in]	mountPoint	The absolute path to the mounted device, NOT the the location of the lost+found dir.
[in]	logTag	If not empty then a log warning message will be printed containing the name of the file that was deleted and referencing the the string in logTag.

◆ createFileIfNeeded()

bool StorageHelper::createFileIfNeeded	(	const std::string &	filePath,
		const size_t	storageSize,
		const uid_t	userId,
		const std::string &	fileSystem
	)

static

Checks if file exists, if yes return true, if not try to create it. If success return true, if file don't exist and cannot be created return false.

Parameters

[in]	filePath	Path to the file that should exist after this function exits
[in]	storageSize	Size of the created image file (in bytes)
[in]	userId	The expected user id set in the xattr of the image file
[in]	fileSystem	Filesystem of created image file

◆ deleteRecursive()

bool StorageHelper::deleteRecursive	(	int	dirfd,
		int	availDepth
	)

static

Recursive function that deletes everything within the supplied directory (as a descriptor).

Parameters

[in]	dirFd	If specified the path should be relative to to this directory.
[in]	availDepth	Maximal depth of recursion

Returns: true on success, false on failure.

◆ getLoopDevice()

std::string StorageHelper::getLoopDevice ( const std::string & backingFile )

static

Get the loop device for a given backing file.

Parameters

[in] backingFile Path of backing file.

Returns: on success a string containing the name of the loop device, empty string on error.

◆ loopDeviceAssociate()

int StorageHelper::loopDeviceAssociate	(	int	fileFd,
		std::string *	loopDevPath
	)

static

Associates a give file descriptor with a loop device.

First the function attempts to get a free loop device, if that succeeds it attaches the supplied file descriptor to it and returns an fd to the loop device and (optionally) writes the path to the loop device in the loopDevPath string.

Parameters

[in]	fileFd	An open file descriptor to associate with the loop device.
[out]	loopDevPath	If not null, the method will write the path to the loop device dev node into the string

Returns: on success returns the open file descriptor to the loop device associated with the file, on failure -1.

◆ openLoopDevice()

int StorageHelper::openLoopDevice ( std::string * loopDevice )

static

Attempts to open an available loop device.

WARNING this method requires sudo

Parameters

[out] loopDevice Loop device name

Returns: on success a positive file descriptor corresponding to a free loop device, -1 on error.

◆ rmdirContents()

bool StorageHelper::rmdirContents	(	int	dirFd,
		const std::string &	path
	)

static

Removes the contents of a directory but leave the actual directory in place.

This is equivalent to the 'rm -rf <dir>/ *' command.

If the pathname given in pathname is relative, then it is interpreted relative to the directory referred to by the file descriptor dirFd, if dirFd is not supplied then it's relative to the cwd.

Warning: This function only supports deleting directories with contents that are less than 128 levels deep, this is to avoid running out of file descriptors.

Parameters

[in]	dirFd	If specified the path should be relative to to this directory.
[in]	path	The path to the directory to create.

Returns: true on success, false on failure.

This is equivalent to the 'cd <dir>; rm -rf *' command.

If the pathname given in path is relative, then it is interpreted relative to the directory referred to by the file descriptor dirFd, if dirFd is not supplied then it's relative to the cwd.

Warning: This function only supports deleting directories with contents that are less than 128 levels deep, this is to avoid running out of file descriptors.

Parameters

[in]	dirFd	If specified the path should be relative to to this directory.
[in]	path	The path to the directory to create.

Returns: true on success, false on failure.

◆ rmdirRecursive()

bool StorageHelper::rmdirRecursive	(	int	dirFd,
		const std::string &	path
	)

static

Removes a directory and all it's contents.

This is equivalent to the 'rm -rf <dir>' command.

If the pathname given in pathname is relative, then it is interpreted relative to the directory referred to by the file descriptor dirFd, if dirFd is not supplied then it's relative to the cwd.

Warning: This function only supports deleting directories with contents that are less than 128 levels deep, this is to avoid running out of file descriptors.

Parameters

[in]	dirFd	If specified the path should be relative to to this directory.
[in]	path	The path to the directory to create.

Returns: true on success, false on failure.

This is equivalent to the 'rm -rf' command.

If the pathname given in pathname is relative, then it is interpreted relative to the directory referred to by the file descriptor dirFd, if dirFd is not supplied then it's relative to the cwd.

Warning: This function only supports deleting directories with contents that are less than 128 levels deep, this is to avoid running out of file descriptors.

Parameters

[in]	dirFd	If specified the path should be relative to to this directory.
[in]	path	The path to the directory to create.

Returns: true on success, false on failure.

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

rdkPlugins/Storage/source/StorageHelper.h
rdkPlugins/Storage/source/StorageHelper.cpp

Static Public Member Functions

Detailed Description

Member Function Documentation

◆ attachFileToLoopDevice()

◆ attachLoopDevice()

◆ cleanMountLostAndFound()

◆ createFileIfNeeded()

◆ deleteRecursive()

◆ getLoopDevice()

◆ loopDeviceAssociate()

◆ openLoopDevice()

◆ rmdirContents()

◆ rmdirRecursive()