/** @file
  EFI Shell protocol as defined in the UEFI Shell 2.0 specification including errata.

  (C) Copyright 2014 Hewlett-Packard Development Company, L.P.<BR>
  Copyright (c) 2006 - 2014, Intel Corporation. All rights reserved.<BR>
  This program and the accompanying materials
  are licensed and made available under the terms and conditions of the BSD License
  which accompanies this distribution.  The full text of the license may be found at
  http://opensource.org/licenses/bsd-license.php

  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.

**/

#ifndef __EFI_SHELL_PROTOCOL__
#define __EFI_SHELL_PROTOCOL__

#include <ShellBase.h>
#include <Guid/FileInfo.h>

#define EFI_SHELL_PROTOCOL_GUID \
  { \
  0x6302d008, 0x7f9b, 0x4f30, { 0x87, 0xac, 0x60, 0xc9, 0xfe, 0xf5, 0xda, 0x4e } \
  }

// replaced EFI_LIST_ENTRY with LIST_ENTRY for simplicity.
// they are identical outside of the name.
typedef struct {
  LIST_ENTRY        Link;       ///< Linked list members.
  EFI_STATUS        Status;     ///< Status of opening the file.  Valid only if Handle != NULL.
  CONST CHAR16      *FullName;  ///< Fully qualified filename.
  CONST CHAR16      *FileName;  ///< name of this file.
  SHELL_FILE_HANDLE Handle;     ///< Handle for interacting with the opened file or NULL if closed.
  EFI_FILE_INFO     *Info;      ///< Pointer to the FileInfo struct for this file or NULL.
} EFI_SHELL_FILE_INFO;

/**
  Returns whether any script files are currently being processed.

  @retval TRUE                 There is at least one script file active.
  @retval FALSE                No script files are active now.

**/
typedef
BOOLEAN
(EFIAPI *EFI_SHELL_BATCH_IS_ACTIVE) (
  VOID
  );

/**
  Closes the file handle.

  This function closes a specified file handle. All 'dirty' cached file data is
  flushed to the device, and the file is closed. In all cases, the handle is
  closed.

  @param[in] FileHandle         The file handle to be closed.

  @retval EFI_SUCCESS           The file closed sucessfully.
**/
typedef
EFI_STATUS
(EFIAPI *EFI_SHELL_CLOSE_FILE)(
  IN SHELL_FILE_HANDLE FileHandle
  );

/**
  Creates a file or directory by name.

  This function creates an empty new file or directory with the specified attributes and
  returns the new file's handle. If the file already exists and is read-only, then
  EFI_INVALID_PARAMETER will be returned.

  If the file already existed, it is truncated and its attributes updated. If the file is
  created successfully, the FileHandle is the file's handle, else, the FileHandle is NULL.

  If the file name begins with >v, then the file handle which is returned refers to the
  shell environment variable with the specified name. If the shell environment variable
  already exists and is non-volatile then EFI_INVALID_PARAMETER is returned.

  @param[in] FileName           Pointer to NULL-terminated file path.
  @param[in] FileAttribs        The new file's attrbiutes.  The different attributes are
                                described in EFI_FILE_PROTOCOL.Open().
  @param[out] FileHandle        On return, points to the created file handle or directory's handle.

  @retval EFI_SUCCESS           The file was opened.  FileHandle points to the new file's handle.
  @retval EFI_INVALID_PARAMETER One of the parameters has an invalid value.
  @retval EFI_UNSUPPORTED       The file path could not be opened.
  @retval EFI_NOT_FOUND         The specified file could not be found on the device, or could not
                                file the file system on the device.
  @retval EFI_NO_MEDIA          The device has no medium.
  @retval EFI_MEDIA_CHANGED     The device has a different medium in it or the medium is no
                                longer supported.
  @retval EFI_DEVICE_ERROR      The device reported an error or can't get the file path according
                                the DirName.
  @retval EFI_VOLUME_CORRUPTED  The file system structures are corrupted.
  @retval EFI_WRITE_PROTECTED   An attempt was made to create a file, or open a file for write
                                when the media is write-protected.
  @retval EFI_ACCESS_DENIED     The service denied access to the file.
  @retval EFI_OUT_OF_RESOURCES  Not enough resources were available to open the file.
  @retval EFI_VOLUME_FULL       The volume is full.
**/
typedef
EFI_STATUS
(EFIAPI *EFI_SHELL_CREATE_FILE)(
  IN CONST CHAR16               *FileName,
  IN UINT64                     FileAttribs,
  OUT SHELL_FILE_HANDLE         *FileHandle
  );

/**
  Deletes the file specified by the file handle.

  This function closes and deletes a file. In all cases, the file handle is closed. If the file
  cannot be deleted, the warning code EFI_WARN_DELETE_FAILURE is returned, but the
  handle is still closed.

  @param[in] FileHandle           The file handle to delete.

  @retval EFI_SUCCESS             The file was closed and deleted and the handle was closed.
  @retval EFI_WARN_DELETE_FAILURE The handle was closed but the file was not deleted.
**/
typedef
EFI_STATUS
(EFIAPI *EFI_SHELL_DELETE_FILE)(
  IN SHELL_FILE_HANDLE FileHandle
  );

/**
  Deletes the file specified by the file name.

  This function deletes a file.

  @param[in] FileName             Points to the NULL-terminated file name.

  @retval EFI_SUCCESS             The file was deleted.
  @retval EFI_WARN_DELETE_FAILURE The handle was closed but the file was not deleted.
**/
typedef
EFI_STATUS
(EFIAPI *EFI_SHELL_DELETE_FILE_BY_NAME)(
  IN CONST CHAR16 *FileName
  );

/**
  Disables the page break output mode.
**/
typedef
VOID
(EFIAPI *EFI_SHELL_DISABLE_PAGE_BREAK) (
  VOID
  );

/**
  Enables the page break output mode.
**/
typedef
VOID
(EFIAPI *EFI_SHELL_ENABLE_PAGE_BREAK) (
  VOID
  );

/**
  Execute the command line.

  This function creates a nested instance of the shell and executes the specified
  command (CommandLine) with the specified environment (Environment). Upon return,
  the status code returned by the specified command is placed in StatusCode.

  If Environment is NULL, then the current environment is used and all changes made
  by the commands executed will be reflected in the current environment. If the
  Environment is non-NULL, then the changes made will be discarded.

  The CommandLine is executed from the current working directory on the current
  device.

  @param[in] ParentImageHandle  A handle of the image that is executing the specified
                                command line.
  @param[in] CommandLine        Points to the NULL-terminated UCS-2 encoded string
                                containing the command line. If NULL then the command-
                                line will be empty.
  @param[in] Environment        Points to a NULL-terminated array of environment
                                variables with the format 'x=y', where x is the
                                environment variable name and y is the value. If this
                                is NULL, then the current shell environment is used.
  @param[out] ErrorCode         Points to the status code returned by the command.

  @retval EFI_SUCCESS           The command executed successfully. The  status code
                                returned by the command is pointed to by StatusCode.
  @retval EFI_INVALID_PARAMETER The parameters are invalid.
  @retval EFI_OUT_OF_RESOURCES  Out of resources.
  @retval EFI_UNSUPPORTED       Nested shell invocations are not allowed.
**/
typedef
EFI_STATUS
(EFIAPI *EFI_SHELL_EXECUTE) (
  IN EFI_HANDLE                 *ParentImageHandle,
  IN CHAR16                     *CommandLine OPTIONAL,
  IN CHAR16                     **Environment OPTIONAL,
  OUT EFI_STATUS                *StatusCode OPTIONAL
  );

/**
  Find files that match a specified pattern.

  This function searches for all files and directories that match the specified
  FilePattern. The FilePattern can contain wild-card characters. The resulting file
  information is placed in the file list FileList.

  The files in the file list are not opened. The OpenMode field is set to 0 and the FileInfo
  field is set to NULL.

  @param[in] FilePattern        Points to a NULL-terminated shell file path, including wildcards.
  @param[out] FileList          On return, points to the start of a file list containing the names
                                of all matching files or else points to NULL if no matching files
                                were found.

  @retval EFI_SUCCESS           Files found.
  @retval EFI_NOT_FOUND         No files found.
  @retval EFI_NO_MEDIA          The device has no media.
  @retval EFI_DEVICE_ERROR      The device reported an error.
  @retval EFI_VOLUME_CORRUPTED  The file system structures are corrupted.
**/
typedef
EFI_STATUS
(EFIAPI *EFI_SHELL_FIND_FILES)(
  IN CONST CHAR16               *FilePattern,
  OUT EFI_SHELL_FILE_INFO       **FileList
  );

/**
  Find all files in a specified directory.

  @param[in] FileDirHandle      Handle of the directory to search.
  @param[out] FileList          On return, points to the list of files in the directory
                                or NULL if there are no files in the directory.

  @retval EFI_SUCCESS           File information was returned successfully.
  @retval EFI_VOLUME_CORRUPTED  The file system structures have been corrupted.
  @retval EFI_DEVICE_ERROR      The device reported an error.
  @retval EFI_NO_MEDIA          The device media is not present.
**/
typedef
EFI_STATUS
(EFIAPI *EFI_SHELL_FIND_FILES_IN_DIR)(
IN SHELL_FILE_HANDLE            FileDirHandle,
OUT EFI_SHELL_FILE_INFO         **FileList
);

/**
  Flushes data back to a device.

  This function flushes all modified data associated with a file to a device.

  @param[in] FileHandle         The handle of the file to flush.

  @retval EFI_SUCCESS           The data was flushed.
  @retval EFI_NO_MEDIA          The device has no medium.
  @retval EFI_DEVICE_ERROR      The device reported an error.
  @retval EFI_VOLUME_CORRUPTED  The file system structures are corrupted.
  @retval EFI_WRITE_PROTECTED   The file or medium is write-protected.
  @retval EFI_ACCESS_DENIED     The file was opened read-only.
  @retval EFI_VOLUME_FULL       The volume is full.
**/
typedef
EFI_STATUS
(EFIAPI *EFI_SHELL_FLUSH_FILE)(
  IN SHELL_FILE_HANDLE FileHandle
  );

/**
  Frees the file list.

  This function cleans up the file list and any related data structures. It has no
  impact on the files themselves.

  @param[in] FileList           The file list to free. Type EFI_SHELL_FILE_INFO is
                                defined in OpenFileList().

  @retval EFI_SUCCESS           Free the file list successfully.
**/
typedef
EFI_STATUS
(EFIAPI *EFI_SHELL_FREE_FILE_LIST) (
  IN EFI_SHELL_FILE_INFO **FileList
  );

/**
  Returns the current directory on the specified device.

  If FileSystemMapping is NULL, it returns the current working directory. If the
  FileSystemMapping is not NULL, it returns the current directory associated with the
  FileSystemMapping. In both cases, the returned name includes the file system
  mapping (i.e. fs0:\current-dir).

  @param[in] FileSystemMapping  A pointer to the file system mapping. If NULL,
                                then the current working directory is returned.

  @retval !=NULL                The current directory.
  @retval NULL                  Current directory does not exist.
**/
typedef
CONST CHAR16 *
(EFIAPI *EFI_SHELL_GET_CUR_DIR) (
  IN CONST CHAR16 *FileSystemMapping OPTIONAL
  );

typedef UINT32 EFI_SHELL_DEVICE_NAME_FLAGS;
#define EFI_DEVICE_NAME_USE_COMPONENT_NAME  0x00000001
#define EFI_DEVICE_NAME_USE_DEVICE_PATH     0x00000002

/**
  Gets the name of the device specified by the device handle.

  This function gets the user-readable name of the device specified by the device
  handle. If no user-readable name could be generated, then *BestDeviceName will be
  NULL and EFI_NOT_FOUND will be returned.

  If EFI_DEVICE_NAME_USE_COMPONENT_NAME is set, then the function will return the
  device's name using the EFI_COMPONENT_NAME2_PROTOCOL, if present on
  DeviceHandle.

  If EFI_DEVICE_NAME_USE_DEVICE_PATH is set, then the function will return the
  device's name using the EFI_DEVICE_PATH_PROTOCOL, if present on DeviceHandle.
  If both EFI_DEVICE_NAME_USE_COMPONENT_NAME and
  EFI_DEVICE_NAME_USE_DEVICE_PATH are set, then
  EFI_DEVICE_NAME_USE_COMPONENT_NAME will have higher priority.

  @param[in] DeviceHandle       The handle of the device.
  @param[in] Flags              Determines the possible sources of component names.
  @param[in] Language           A pointer to the language specified for the device
                                name, in the same format as described in the UEFI
                                specification, Appendix M.
  @param[out] BestDeviceName    On return, points to the callee-allocated NULL-
                                terminated name of the device. If no device name
                                could be found, points to NULL. The name must be
                                freed by the caller...

  @retval EFI_SUCCESS           Get the name successfully.
  @retval EFI_NOT_FOUND         Fail to get the device name.
**/
typedef
EFI_STATUS
(EFIAPI *EFI_SHELL_GET_DEVICE_NAME) (
  IN EFI_HANDLE                   DeviceHandle,
  IN EFI_SHELL_DEVICE_NAME_FLAGS  Flags,
  IN CHAR8                        *Language,
  OUT CHAR16                      **BestDeviceName
  );

/**
  Gets the device path from the mapping.

  This function gets the device path associated with a mapping.

  @param[in] Mapping                A pointer to the mapping

  @retval !=NULL                Pointer to the device path that corresponds to the
                                device mapping. The returned pointer does not need
                                to be freed.
  @retval NULL                  There is no device path associated with the
                                specified mapping.
**/
typedef
CONST EFI_DEVICE_PATH_PROTOCOL *
(EFIAPI *EFI_SHELL_GET_DEVICE_PATH_FROM_MAP) (
  IN CONST CHAR16 *Mapping
  );

/**
  Converts a file system style name to a device path.

  This function converts a file system style name to a device path, by replacing any
  mapping references to the associated device path.

  @param[in] Path               The pointer to the path.

  @return                       The pointer of the file path. The file path is callee
                                allocated and should be freed by the caller.
**/
typedef
EFI_DEVICE_PATH_PROTOCOL *
(EFIAPI *EFI_SHELL_GET_DEVICE_PATH_FROM_FILE_PATH) (
  IN CONST CHAR16 *Path
  );

/**
  Gets either a single or list of environment variables.

  If name is not NULL then this function returns the current value of the specified
  environment variable.

  If Name is NULL than a list of all environment variable names is returned.  Each a
  NULL terminated string with a double NULL terminating the list.

  @param[in] Name               A pointer to the environment variable name.  If
                                Name is NULL, then the function will return all
                                of the defined shell environment variables.  In
                                the case where multiple environment variables are
                                being returned, each variable will be terminated by
                                a NULL, and the list will be terminated by a double
                                NULL.

  @return                       A pointer to the returned string.
                                The returned pointer does not need to be freed by the caller.

  @retval NULL                  The environment variable doesn't exist or there are
                                no environment variables.
**/
typedef
CONST CHAR16 *
(EFIAPI *EFI_SHELL_GET_ENV) (
  IN CONST CHAR16 *Name OPTIONAL
  );

/**
  Gets the environment variable and Attributes, or list of environment variables.  Can be 
  used instead of GetEnv().

  This function returns the current value of the specified environment variable and
  the Attributes. If no variable name was specified, then all of the known
  variables will be returned.

  @param[in] Name               A pointer to the environment variable name. If Name is NULL,
                                then the function will return all of the defined shell 
                                environment variables. In the case where multiple environment
                                variables are being returned, each variable will be terminated 
                                by a NULL, and the list will be terminated by a double NULL.
  @param[out] Attributes        If not NULL, a pointer to the returned attributes bitmask for
                                the environment variable. In the case where Name is NULL, and
                                multiple environment variables are being returned, Attributes
                                is undefined.

  @retval NULL                  The environment variable doesn't exist.  
  @return                       The environment variable's value. The returned pointer does not 
                                need to be freed by the caller.  
**/
typedef
CONST CHAR16 *
(EFIAPI *EFI_SHELL_GET_ENV_EX) (
  IN  CONST CHAR16 *Name,
  OUT       UINT32 *Attributes OPTIONAL
  );

/**
  Gets the file information from an open file handle.

  This function allocates a buffer to store the file's information. It's the caller's
  responsibility to free the buffer.

  @param[in] FileHandle         A File Handle.

  @retval NULL                  Cannot get the file info.
  @return                       A pointer to a buffer with file information.
**/
typedef
EFI_FILE_INFO *
(EFIAPI *EFI_SHELL_GET_FILE_INFO)(
  IN SHELL_FILE_HANDLE FileHandle
  );

/**
  Converts a device path to a file system-style path.

  This function converts a device path to a file system path by replacing part, or all, of
  the device path with the file-system mapping. If there are more than one application
  file system mappings, the one that most closely matches Path will be used.

  @param[in] Path               The pointer to the device path.

  @return                       The pointer of the NULL-terminated file path. The path
                                is callee-allocated and should be freed by the caller.
**/
typedef
CHAR16 *
(EFIAPI *EFI_SHELL_GET_FILE_PATH_FROM_DEVICE_PATH) (
  IN CONST EFI_DEVICE_PATH_PROTOCOL *Path
  );

/**
  Gets a file's current position.

  This function returns the current file position for the file handle. For directories, the
  current file position has no meaning outside of the file system driver and as such, the
  operation is not supported.

  @param[in] FileHandle         The file handle on which to get the current position.
  @param[out] Position          Byte position from the start of the file.

  @retval EFI_SUCCESS           Data was accessed.
  @retval EFI_UNSUPPORTED       The request is not valid on open directories.
**/
typedef
EFI_STATUS
(EFIAPI *EFI_SHELL_GET_FILE_POSITION)(
  IN SHELL_FILE_HANDLE FileHandle,
  OUT UINT64 *Position
  );

/**
  Gets the size of a file.

  This function returns the size of the file specified by FileHandle.

  @param[in] FileHandle         The handle of the file.
  @param[out] Size              The size of this file.

  @retval EFI_SUCCESS           Get the file's size.
  @retval EFI_DEVICE_ERROR      Can't access the file.
**/
typedef
EFI_STATUS
(EFIAPI *EFI_SHELL_GET_FILE_SIZE)(
  IN SHELL_FILE_HANDLE FileHandle,
  OUT UINT64 *Size
  );

/**
  Get the GUID value from a human readable name.

  If GuidName is a known GUID name, then update Guid to have the correct value for
  that GUID.

  This function is only available when the major and minor versions in the
  EfiShellProtocol are greater than or equal to 2 and 1, respectively.

  @param[in]  GuidName   A pointer to the localized name for the GUID being queried.
  @param[out] Guid       A pointer to the GUID structure to be filled in.

  @retval EFI_SUCCESS             The operation was successful.
  @retval EFI_INVALID_PARAMETER   Guid was NULL.
  @retval EFI_INVALID_PARAMETER   GuidName was NULL.
  @retval EFI_NOT_FOUND           GuidName is not a known GUID Name.
**/
typedef
EFI_STATUS
(EFIAPI *EFI_SHELL_GET_GUID_FROM_NAME)(
  IN  CONST CHAR16   *GuidName,
  OUT       EFI_GUID *Guid
  );

/**
  Get the human readable name for a GUID from the value.

  If Guid is assigned a name, then update *GuidName to point to the name. The callee
  should not modify the value.

  This function is only available when the major and minor versions in the
  EfiShellProtocol are greater than or equal to 2 and 1, respectively.

  @param[in]  Guid       A pointer to the GUID being queried.
  @param[out] GuidName   A pointer to a pointer the localized to name for the GUID being requested

  @retval EFI_SUCCESS             The operation was successful.
  @retval EFI_INVALID_PARAMETER   Guid was NULL.
  @retval EFI_INVALID_PARAMETER   GuidName was NULL.
  @retval EFI_NOT_FOUND           Guid is not assigned a name.
**/
typedef
EFI_STATUS
(EFIAPI *EFI_SHELL_GET_GUID_NAME)(
  IN  CONST EFI_GUID *Guid,
  OUT CONST CHAR16   **GuidName
  );

/**
  Return help information about a specific command.

  This function returns the help information for the specified command. The help text
  can be internal to the shell or can be from a UEFI Shell manual page.

  If Sections is specified, then each section name listed will be compared in a casesensitive
  manner, to the section names described in Appendix B. If the section exists,
  it will be appended to the returned help text. If the section does not exist, no
  information will be returned. If Sections is NULL, then all help text information
  available will be returned.

  @param[in] Command            Points to the NULL-terminated UEFI Shell command name.
  @param[in] Sections           Points to the NULL-terminated comma-delimited
                                section names to return. If NULL, then all
                                sections will be returned.
  @param[out] HelpText          On return, points to a callee-allocated buffer
                                containing all specified help text.

  @retval EFI_SUCCESS           The help text was returned.
  @retval EFI_OUT_OF_RESOURCES  The necessary buffer could not be allocated to hold the
                                returned help text.
  @retval EFI_INVALID_PARAMETER HelpText is NULL.
  @retval EFI_NOT_FOUND         There is no help text available for Command.
**/
typedef
EFI_STATUS
(EFIAPI *EFI_SHELL_GET_HELP_TEXT) (
  IN CONST CHAR16 *Command,
  IN CONST CHAR16 *Sections OPTIONAL,
  OUT CHAR16 **HelpText
  );

/**
  Gets the mapping(s) that most closely matches the device path.

  This function gets the mapping which corresponds to the device path *DevicePath. If
  there is no exact match, then the mapping which most closely matches *DevicePath
  is returned, and *DevicePath is updated to point to the remaining portion of the
  device path. If there is an exact match, the mapping is returned and *DevicePath
  points to the end-of-device-path node.

  If there are multiple map names they will be semi-colon seperated in the
  NULL-terminated string.

  @param[in, out] DevicePath     On entry, points to a device path pointer. On
                                 exit, updates the pointer to point to the
                                 portion of the device path after the mapping.

  @retval NULL                  No mapping was found.
  @retval !=NULL                Pointer to NULL-terminated mapping. The buffer
                                is callee allocated and should be freed by the caller.
**/
typedef
CONST CHAR16 *
(EFIAPI *EFI_SHELL_GET_MAP_FROM_DEVICE_PATH) (
  IN OUT EFI_DEVICE_PATH_PROTOCOL **DevicePath
  );

/**
  Gets the enable status of the page break output mode.

  User can use this function to determine current page break mode.

  @retval TRUE                  The page break output mode is enabled.
  @retval FALSE                 The page break output mode is disabled.
**/
typedef
BOOLEAN
(EFIAPI *EFI_SHELL_GET_PAGE_BREAK) (
  VOID
  );

/**
  Judges whether the active shell is the root shell.

  This function makes the user to know that whether the active Shell is the root shell.

  @retval TRUE                  The active Shell is the root Shell.
  @retval FALSE                 The active Shell is NOT the root Shell.
**/
typedef
BOOLEAN
(EFIAPI *EFI_SHELL_IS_ROOT_SHELL) (
VOID
);

/**
  Opens a file or a directory by file name.

  This function opens the specified file in the specified OpenMode and returns a file
  handle.
  If the file name begins with '>v', then the file handle which is returned refers to the
  shell environment variable with the specified name. If the shell environment variable
  exists, is non-volatile and the OpenMode indicates EFI_FILE_MODE_WRITE, then
  EFI_INVALID_PARAMETER is returned.

  If the file name is '>i', then the file handle which is returned refers to the standard
  input. If the OpenMode indicates EFI_FILE_MODE_WRITE, then EFI_INVALID_PARAMETER
  is returned.

  If the file name is '>o', then the file handle which is returned refers to the standard
  output. If the OpenMode indicates EFI_FILE_MODE_READ, then EFI_INVALID_PARAMETER
  is returned.

  If the file name is '>e', then the file handle which is returned refers to the standard
  error. If the OpenMode indicates EFI_FILE_MODE_READ, then EFI_INVALID_PARAMETER
  is returned.

  If the file name is 'NUL', then the file handle that is returned refers to the standard NUL
  file. If the OpenMode indicates EFI_FILE_MODE_READ, then EFI_INVALID_PARAMETER is
  returned.

  If return EFI_SUCCESS, the FileHandle is the opened file's handle, else, the
  FileHandle is NULL.

  @param[in] FileName           Points to the NULL-terminated UCS-2 encoded file name.
  @param[out] FileHandle        On return, points to the file handle.
  @param[in] OpenMode           File open mode. Either EFI_FILE_MODE_READ or
                                EFI_FILE_MODE_WRITE from section 12.4 of the UEFI
                                Specification.
  @retval EFI_SUCCESS           The file was opened. FileHandle has the opened file's handle.
  @retval EFI_INVALID_PARAMETER One of the parameters has an invalid value. FileHandle is NULL.
  @retval EFI_UNSUPPORTED       Could not open the file path. FileHandle is NULL.
  @retval EFI_NOT_FOUND         The specified file could not be found on the device or the file
                                system could not be found on the device. FileHandle is NULL.
  @retval EFI_NO_MEDIA          The device has no medium. FileHandle is NULL.
  @retval EFI_MEDIA_CHANGED     The device has a different medium in it or the medium is no
                                longer supported. FileHandle is NULL.
  @retval EFI_DEVICE_ERROR      The device reported an error or can't get the file path according
                                the FileName. FileHandle is NULL.
  @retval EFI_VOLUME_CORRUPTED  The file system structures are corrupted. FileHandle is NULL.
  @retval EFI_WRITE_PROTECTED   An attempt was made to create a file, or open a file for write
                                when the media is write-protected. FileHandle is NULL.
  @retval EFI_ACCESS_DENIED     The service denied access to the file. FileHandle is NULL.
  @retval EFI_OUT_OF_RESOURCES  Not enough resources were available to open the file. FileHandle
                                is NULL.
  @retval EFI_VOLUME_FULL       The volume is full. FileHandle is NULL.
**/
typedef
EFI_STATUS
(EFIAPI *EFI_SHELL_OPEN_FILE_BY_NAME) (
  IN CONST CHAR16 *FileName,
  OUT SHELL_FILE_HANDLE *FileHandle,
  IN UINT64 OpenMode
  );

/**
  Opens the files that match the path specified.

  This function opens all of the files specified by Path. Wildcards are processed
  according to the rules specified in UEFI Shell 2.0 spec section 3.7.1. Each
  matching file has an EFI_SHELL_FILE_INFO structure created in a linked list.

  @param[in] Path                A pointer to the path string.
  @param[in] OpenMode            Specifies the mode used to open each file, EFI_FILE_MODE_READ or
                                 EFI_FILE_MODE_WRITE.
  @param[in, out] FileList       Points to the start of a list of files opened.

  @retval EFI_SUCCESS           Create the file list successfully.
  @return                       Can't create the file list.
**/
typedef
EFI_STATUS
(EFIAPI *EFI_SHELL_OPEN_FILE_LIST) (
  IN CHAR16 *Path,
  IN UINT64 OpenMode,
  IN OUT EFI_SHELL_FILE_INFO **FileList
  );

/**
  Opens the root directory of a device.

  This function opens the root directory of a device and returns a file handle to it.

  @param[in] DevicePath         Points to the device path corresponding to the device where the
                                EFI_SIMPLE_FILE_SYSTEM_PROTOCOL is installed.
  @param[out] FileHandle        On exit, points to the file handle corresponding to the root directory on the
                                device.

  @retval EFI_SUCCESS           Root opened successfully.
  @retval EFI_NOT_FOUND         EFI_SIMPLE_FILE_SYSTEM could not be found or the root directory
                                could not be opened.
  @retval EFI_VOLUME_CORRUPTED  The data structures in the volume were corrupted.
  @retval EFI_DEVICE_ERROR      The device had an error.
**/
typedef
EFI_STATUS
(EFIAPI *EFI_SHELL_OPEN_ROOT)(
  IN EFI_DEVICE_PATH_PROTOCOL *DevicePath,
  OUT SHELL_FILE_HANDLE *FileHandle
  );

/**
  Opens the root directory of a device on a handle.

  This function opens the root directory of a device and returns a file handle to it.

  @param[in] DeviceHandle       The handle of the device that contains the volume.
  @param[out] FileHandle        On exit, points to the file handle corresponding to the root directory on the
                                device.

  @retval EFI_SUCCESS           Root opened successfully.
  @retval EFI_NOT_FOUND         EFI_SIMPLE_FILE_SYSTEM could not be found or the root directory
                                could not be opened.
  @retval EFI_VOLUME_CORRUPTED  The data structures in the volume were corrupted.
  @retval EFI_DEVICE_ERROR      The device had an error.
**/
typedef
EFI_STATUS
(EFIAPI *EFI_SHELL_OPEN_ROOT_BY_HANDLE)(
  IN EFI_HANDLE DeviceHandle,
  OUT SHELL_FILE_HANDLE *FileHandle
  );

/**
  Reads data from the file.

  If FileHandle is not a directory, the function reads the requested number of bytes
  from the file at the file's current position and returns them in Buffer. If the read goes
  beyond the end of the file, the read length is truncated to the end of the file. The file's
  current position is increased by the number of bytes returned.
  If FileHandle is a directory, then an error is returned.

  @param[in] FileHandle          The opened file handle for read.
  @param[in] ReadSize            On input, the size of Buffer, in bytes. On output, the amount of data read.
  @param[in, out] Buffer         The buffer in which data is read.

  @retval EFI_SUCCESS           Data was read.
  @retval EFI_NO_MEDIA          The device has no media.
  @retval EFI_DEVICE_ERROR      The device reported an error.
  @retval EFI_VOLUME_CORRUPTED  The file system structures are corrupted.
  @retval EFI_BUFFER_TO_SMALL   Buffer is too small. ReadSize contains required size.
**/
typedef
EFI_STATUS
(EFIAPI *EFI_SHELL_READ_FILE) (
  IN SHELL_FILE_HANDLE FileHandle,
  IN OUT UINTN *ReadSize,
  IN OUT VOID *Buffer
  );

/**
  Register a GUID and a localized human readable name for it.

  If Guid is not assigned a name, then assign GuidName to Guid.  This list of GUID
  names must be used whenever a shell command outputs GUID information.

  This function is only available when the major and minor versions in the
  EfiShellProtocol are greater than or equal to 2 and 1, respectively.

  @param[in] Guid       A pointer to the GUID being registered.
  @param[in] GuidName   A pointer to the localized name for the GUID being registered.

  @retval EFI_SUCCESS             The operation was successful.
  @retval EFI_INVALID_PARAMETER   Guid was NULL.
  @retval EFI_INVALID_PARAMETER   GuidName was NULL.
  @retval EFI_ACCESS_DENIED       Guid already is assigned a name.
**/
typedef
EFI_STATUS
(EFIAPI *EFI_SHELL_REGISTER_GUID_NAME)(
  IN CONST EFI_GUID *Guid,
  IN CONST CHAR16   *GuidName
  );

/**
  Deletes the duplicate file names files in the given file list.

  @param[in] FileList           A pointer to the first entry in the file list.

  @retval EFI_SUCCESS           Always success.
**/
typedef
EFI_STATUS
(EFIAPI *EFI_SHELL_REMOVE_DUP_IN_FILE_LIST) (
  IN EFI_SHELL_FILE_INFO **FileList
  );

/**
  Changes a shell command alias.

  This function creates an alias for a shell command.

  @param[in] Command            Points to the NULL-terminated shell command or existing alias.
  @param[in] Alias              Points to the NULL-terminated alias for the shell command. If this is NULL, and
                                Command refers to an alias, that alias will be deleted.
  @param[in] Replace            If TRUE and the alias already exists, then the existing alias will be replaced. If
                                FALSE and the alias already exists, then the existing alias is unchanged and
                                EFI_ACCESS_DENIED is returned.
  @param[in] Volatile           if TRUE the Alias being set will be stored in a volatile fashion.  if FALSE the
                                Alias being set will be stored in a non-volatile fashion.

  @retval EFI_SUCCESS           Alias created or deleted successfully.
  @retval EFI_ACCESS_DENIED     The alias is a built-in alias or already existed and Replace was set to
                                FALSE.
**/
typedef
EFI_STATUS
(EFIAPI *EFI_SHELL_SET_ALIAS)(
  IN CONST CHAR16 *Command,
  IN CONST CHAR16 *Alias,
  IN BOOLEAN Replace,
  IN BOOLEAN Volatile
  );

/**
  This function returns the command associated with a alias or a list of all
  alias'.

  @param[in] Alias              Points to the NULL-terminated shell alias.
                                If this parameter is NULL, then all
                                aliases will be returned in ReturnedData.
  @param[out] Volatile          Upon return of a single command if TRUE indicates
                                this is stored in a volatile fashion.  FALSE otherwise.
  @return                      	If Alias is not NULL, it will return a pointer to
                                the NULL-terminated command for that alias.
                                If Alias is NULL, ReturnedData points to a ';'
                                delimited list of alias (e.g.
                                ReturnedData = "dir;del;copy;mfp") that is NULL-terminated.
  @retval NULL                  An error ocurred.
  @retval NULL                  Alias was not a valid Alias.
**/
typedef
CONST CHAR16 *
(EFIAPI *EFI_SHELL_GET_ALIAS)(
  IN  CONST CHAR16 *Alias,
  OUT BOOLEAN      *Volatile OPTIONAL
  );

/**
  Changes the current directory on the specified device.

  If the FileSystem is NULL, and the directory Dir does not contain a file system's
  mapped name, this function changes the current working directory. If FileSystem is
  NULL and the directory Dir contains a mapped name, then the current file system and
  the current directory on that file system are changed.

  If FileSystem is not NULL, and Dir is NULL, then this changes the current working file
  system.

  If FileSystem is not NULL and Dir is not NULL, then this function changes the current
  directory on the specified file system.

  If the current working directory or the current working file system is changed then the
  %cwd% environment variable will be updated.

  @param[in] FileSystem         A pointer to the file system's mapped name. If NULL, then the current working
                                directory is changed.
  @param[in] Dir                Points to the NULL-terminated directory on the device specified by FileSystem.

  @retval NULL                  Current directory does not exist.
  @return                       The current directory.
**/
typedef
EFI_STATUS
(EFIAPI *EFI_SHELL_SET_CUR_DIR) (
  IN CONST CHAR16 *FileSystem OPTIONAL,
  IN CONST CHAR16 *Dir
  );

/**
  Sets the environment variable.

  This function changes the current value of the specified environment variable. If the
  environment variable exists and the Value is an empty string, then the environment
  variable is deleted. If the environment variable exists and the Value is not an empty
  string, then the value of the environment variable is changed. If the environment
  variable does not exist and the Value is an empty string, there is no action. If the
  environment variable does not exist and the Value is a non-empty string, then the
  environment variable is created and assigned the specified value.

  For a description of volatile and non-volatile environment variables, see UEFI Shell
  2.0 specification section 3.6.1.

  @param[in] Name               Points to the NULL-terminated environment variable name.
  @param[in] Value              Points to the NULL-terminated environment variable value. If the value is an
                                empty string then the environment variable is deleted.
  @param[in] Volatile           Indicates whether the variable is non-volatile (FALSE) or volatile (TRUE).

  @retval EFI_SUCCESS           The environment variable was successfully updated.
**/
typedef
EFI_STATUS
(EFIAPI *EFI_SHELL_SET_ENV) (
  IN CONST CHAR16 *Name,
  IN CONST CHAR16 *Value,
  IN BOOLEAN Volatile
  );

/**
  Sets the file information to an opened file handle.

  This function changes file information.  All file information in the EFI_FILE_INFO
  struct will be updated to the passed in data.

  @param[in] FileHandle         A file handle.
  @param[in] FileInfo           Points to new file information.

  @retval EFI_SUCCESS           The information was set.
  @retval EFI_NO_MEDIA          The device has no medium.
  @retval EFI_DEVICE_ERROR      The device reported an error.
  @retval EFI_VOLUME_CORRUPTED  The file system structures are corrupted.
  @retval EFI_WRITE_PROTECTED   The file or medium is write-protected.
  @retval EFI_ACCESS_DENIED     The file was opened read-only.
  @retval EFI_VOLUME_FULL       The volume is full.
  @retval EFI_BAD_BUFFER_SIZE   BufferSize is smaller than the size of EFI_FILE_INFO.
**/
typedef
EFI_STATUS
(EFIAPI *EFI_SHELL_SET_FILE_INFO)(
  IN SHELL_FILE_HANDLE FileHandle,
  IN CONST EFI_FILE_INFO *FileInfo
  );

/**
  Sets a file's current position.

  This function sets the current file position for the handle to the position supplied. With
  the exception of seeking to position 0xFFFFFFFFFFFFFFFF, only absolute positioning is
  supported, and seeking past the end of the file is allowed (a subsequent write would
  grow the file). Seeking to position 0xFFFFFFFFFFFFFFFF causes the current position
  to be set to the end of the file.

  @param[in] FileHandle         The file handle on which requested position will be set.
  @param[in] Position           Byte position from the start of the file.

  @retval EFI_SUCCESS           Data was written.
  @retval EFI_UNSUPPORTED       The seek request for nonzero is not valid on open directories.
**/
typedef
EFI_STATUS
(EFIAPI *EFI_SHELL_SET_FILE_POSITION)(
  IN SHELL_FILE_HANDLE FileHandle,
  IN UINT64 Position
  );

/**
  This function creates a mapping for a device path.

  @param[in] DevicePath         Points to the device path. If this is NULL and Mapping points to a valid mapping,
                                then the mapping will be deleted.
  @param[in] Mapping            Points to the NULL-terminated mapping for the device path.

  @retval EFI_SUCCESS           Mapping created or deleted successfully.
  @retval EFI_NO_MAPPING        There is no handle that corresponds exactly to DevicePath. See the
                                boot service function LocateDevicePath().
  @retval EFI_ACCESS_DENIED     The mapping is a built-in alias.
**/
typedef
EFI_STATUS
(EFIAPI *EFI_SHELL_SET_MAP)(
  IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath,
  IN CONST CHAR16 *Mapping
  );

/**
  Writes data to the file.

  This function writes the specified number of bytes to the file at the current file position.
  The current file position is advanced the actual number of bytes written, which is
  returned in BufferSize. Partial writes only occur when there has been a data error
  during the write attempt (such as "volume space full"). The file automatically grows to
  hold the data, if required.

  Direct writes to opened directories are not supported.

  @param[in] FileHandle              The opened file handle for writing.
  @param[in, out] BufferSize         On input, size of Buffer.
  @param[in] Buffer                  The buffer in which data to write.

  @retval EFI_SUCCESS               Data was written.
  @retval EFI_UNSUPPORTED           Writes to open directory are not supported.
  @retval EFI_NO_MEDIA              The device has no media.
  @retval EFI_DEVICE_ERROR          The device reported an error.
  @retval EFI_VOLUME_CORRUPTED      The file system structures are corrupted.
  @retval EFI_WRITE_PROTECTED       The device is write-protected.
  @retval EFI_ACCESS_DENIED         The file was open for read only.
  @retval EFI_VOLUME_FULL           The volume is full.
**/
typedef
EFI_STATUS
(EFIAPI *EFI_SHELL_WRITE_FILE)(
  IN SHELL_FILE_HANDLE          FileHandle,
  IN OUT UINTN                  *BufferSize,
  IN VOID                       *Buffer
  );

//
// EFI_SHELL_PROTOCOL has been updated since UEFI Shell Spec 2.0
// Usage of this protocol will require version checking before attempting
// to use any new members.  There is no need to check the version for
// members that existed in UEFI Shell Spec 2.0.
//
// Update below for any future UEFI Shell spec changes to this protocol.
//
// Check EFI_SHELL_PROTOCOL MajorVersion and MinorVersion:
// if ((2 == gEfiShellProtocol->MajorVersion) &&
//     (0 == gEfiShellProtocol->MinorVersion)) {
//   //
//   // Cannot call:
//   // RegisterGuidName - UEFI Shell 2.1
//   // GetGuidName      - UEFI Shell 2.1
//   // GetGuidFromName  - UEFI Shell 2.1
//   // GetEnvEx         - UEFI Shell 2.1
//   //
// } else {
//   //
//   // Can use all members
//   //
// }
//
typedef struct _EFI_SHELL_PROTOCOL {
  EFI_SHELL_EXECUTE                         Execute;
  EFI_SHELL_GET_ENV                         GetEnv;
  EFI_SHELL_SET_ENV                         SetEnv;
  EFI_SHELL_GET_ALIAS                       GetAlias;
  EFI_SHELL_SET_ALIAS                       SetAlias;
  EFI_SHELL_GET_HELP_TEXT                   GetHelpText;
  EFI_SHELL_GET_DEVICE_PATH_FROM_MAP        GetDevicePathFromMap;
  EFI_SHELL_GET_MAP_FROM_DEVICE_PATH        GetMapFromDevicePath;
  EFI_SHELL_GET_DEVICE_PATH_FROM_FILE_PATH  GetDevicePathFromFilePath;
  EFI_SHELL_GET_FILE_PATH_FROM_DEVICE_PATH  GetFilePathFromDevicePath;
  EFI_SHELL_SET_MAP                         SetMap;
  EFI_SHELL_GET_CUR_DIR                     GetCurDir;
  EFI_SHELL_SET_CUR_DIR                     SetCurDir;
  EFI_SHELL_OPEN_FILE_LIST                  OpenFileList;
  EFI_SHELL_FREE_FILE_LIST                  FreeFileList;
  EFI_SHELL_REMOVE_DUP_IN_FILE_LIST         RemoveDupInFileList;
  EFI_SHELL_BATCH_IS_ACTIVE                 BatchIsActive;
  EFI_SHELL_IS_ROOT_SHELL                   IsRootShell;
  EFI_SHELL_ENABLE_PAGE_BREAK               EnablePageBreak;
  EFI_SHELL_DISABLE_PAGE_BREAK              DisablePageBreak;
  EFI_SHELL_GET_PAGE_BREAK                  GetPageBreak;
  EFI_SHELL_GET_DEVICE_NAME                 GetDeviceName;
  EFI_SHELL_GET_FILE_INFO                   GetFileInfo;
  EFI_SHELL_SET_FILE_INFO                   SetFileInfo;
  EFI_SHELL_OPEN_FILE_BY_NAME               OpenFileByName;
  EFI_SHELL_CLOSE_FILE                      CloseFile;
  EFI_SHELL_CREATE_FILE                     CreateFile;
  EFI_SHELL_READ_FILE                       ReadFile;
  EFI_SHELL_WRITE_FILE                      WriteFile;
  EFI_SHELL_DELETE_FILE                     DeleteFile;
  EFI_SHELL_DELETE_FILE_BY_NAME             DeleteFileByName;
  EFI_SHELL_GET_FILE_POSITION               GetFilePosition;
  EFI_SHELL_SET_FILE_POSITION               SetFilePosition;
  EFI_SHELL_FLUSH_FILE                      FlushFile;
  EFI_SHELL_FIND_FILES                      FindFiles;
  EFI_SHELL_FIND_FILES_IN_DIR               FindFilesInDir;
  EFI_SHELL_GET_FILE_SIZE                   GetFileSize;
  EFI_SHELL_OPEN_ROOT                       OpenRoot;
  EFI_SHELL_OPEN_ROOT_BY_HANDLE             OpenRootByHandle;
  EFI_EVENT                                 ExecutionBreak;
  UINT32                                    MajorVersion;
  UINT32                                    MinorVersion;
  // Added for Shell 2.1
  EFI_SHELL_REGISTER_GUID_NAME              RegisterGuidName;
  EFI_SHELL_GET_GUID_NAME                   GetGuidName;
  EFI_SHELL_GET_GUID_FROM_NAME              GetGuidFromName;
  EFI_SHELL_GET_ENV_EX                      GetEnvEx;
} EFI_SHELL_PROTOCOL;

extern EFI_GUID gEfiShellProtocolGuid;

enum ShellVersion {
  SHELL_MAJOR_VERSION = 2,
  SHELL_MINOR_VERSION = 1
};

#endif