audk/ShellPkg/Application/Shell/ShellEnvVar.h

/** @file
  function definitions for shell environment functions.

  the following includes are required:
//#include <Guid/ShellVariableGuid.h>
//#include <Library/UefiRuntimeServicesTableLib.h>


  Copyright (c) 2009 - 2016, 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 _SHELL_ENVIRONMENT_VARIABLE_HEADER_
#define _SHELL_ENVIRONMENT_VARIABLE_HEADER_

typedef struct {
  LIST_ENTRY  Link;
  CHAR16      *Key;
  CHAR16      *Val;
  UINT32      Atts;
} ENV_VAR_LIST;

//
// The list is used to cache the environment variables.
//
extern ENV_VAR_LIST    gShellEnvVarList;


/**
  Reports whether an environment variable is Volatile or Non-Volatile.

  @param EnvVarName             The name of the environment variable in question
  @param Volatile               Return TRUE if the environment variable is volatile

  @retval EFI_SUCCESS           The volatile attribute is returned successfully
  @retval others                Some errors happened.
**/
EFI_STATUS
IsVolatileEnv (
  IN CONST CHAR16 *EnvVarName,
  OUT BOOLEAN     *Volatile
  );

/**
  Delete a Non-Violatile environment variable.

  This will use the Runtime Services call SetVariable to remove a non-violatile variable.

  @param EnvVarName             The name of the environment variable in question

  @retval EFI_SUCCESS           The variable was deleted sucessfully
  @retval other                 An error ocurred
  @sa SetVariable
**/
#define SHELL_DELETE_ENVIRONMENT_VARIABLE(EnvVarName) \
  (gRT->SetVariable((CHAR16*)EnvVarName, \
  &gShellVariableGuid,          \
  0,                            \
  0,                            \
  NULL))

/**
  Set a Non-Violatile environment variable.

  This will use the Runtime Services call SetVariable to set a non-violatile variable.

  @param EnvVarName             The name of the environment variable in question
  @param BufferSize             UINTN size of Buffer
  @param Buffer                 Pointer to value to set variable to

  @retval EFI_SUCCESS           The variable was changed sucessfully
  @retval other                 An error ocurred
  @sa SetVariable
**/
#define SHELL_SET_ENVIRONMENT_VARIABLE_NV(EnvVarName,BufferSize,Buffer)  \
  (gRT->SetVariable((CHAR16*)EnvVarName,                          \
  &gShellVariableGuid,                                            \
  EFI_VARIABLE_NON_VOLATILE|EFI_VARIABLE_BOOTSERVICE_ACCESS,      \
  BufferSize,                                                     \
  (VOID*)Buffer))

/**
  Get an environment variable.

  This will use the Runtime Services call GetVariable to get a variable.

  @param EnvVarName             The name of the environment variable in question
  @param BufferSize             Pointer to the UINTN size of Buffer
  @param Buffer                 Pointer buffer to get variable value into

  @retval EFI_SUCCESS           The variable's value was retrieved sucessfully
  @retval other                 An error ocurred
  @sa SetVariable
**/
#define SHELL_GET_ENVIRONMENT_VARIABLE(EnvVarName,BufferSize,Buffer)    \
  (gRT->GetVariable((CHAR16*)EnvVarName,                        \
  &gShellVariableGuid,                                          \
  0,                                                            \
  BufferSize,                                                   \
  Buffer))

/**
  Get an environment variable.

  This will use the Runtime Services call GetVariable to get a variable.

  @param EnvVarName             The name of the environment variable in question
  @param Atts                   Pointer to the UINT32 for attributes (or NULL)
  @param BufferSize             Pointer to the UINTN size of Buffer
  @param Buffer                 Pointer buffer to get variable value into

  @retval EFI_SUCCESS           The variable's value was retrieved sucessfully
  @retval other                 An error ocurred
  @sa SetVariable
**/
#define SHELL_GET_ENVIRONMENT_VARIABLE_AND_ATTRIBUTES(EnvVarName,Atts,BufferSize,Buffer)    \
  (gRT->GetVariable((CHAR16*)EnvVarName,                        \
  &gShellVariableGuid,                                          \
  Atts,                                                            \
  BufferSize,                                                   \
  Buffer))

/**
  Set a Violatile environment variable.

  This will use the Runtime Services call SetVariable to set a violatile variable.

  @param EnvVarName             The name of the environment variable in question
  @param BufferSize             UINTN size of Buffer
  @param Buffer                 Pointer to value to set variable to

  @retval EFI_SUCCESS           The variable was changed sucessfully
  @retval other                 An error ocurred
  @sa SetVariable
**/
#define SHELL_SET_ENVIRONMENT_VARIABLE_V(EnvVarName,BufferSize,Buffer) \
  (gRT->SetVariable((CHAR16*)EnvVarName,                      \
  &gShellVariableGuid,                                        \
  EFI_VARIABLE_BOOTSERVICE_ACCESS,                            \
  BufferSize,                                                 \
  (VOID*)Buffer))

/**
  Creates a list of all Shell-Guid-based environment variables.

  @param[in, out] List           The pointer to pointer to LIST_ENTRY object for
                                 storing this list.

  @retval EFI_SUCCESS           the list was created sucessfully.
**/
EFI_STATUS
GetEnvironmentVariableList(
  IN OUT LIST_ENTRY *List
  );

/**
  Sets a list of all Shell-Guid-based environment variables.  this will
  also eliminate all pre-existing shell environment variables (even if they
  are not on the list).

  This function will also deallocate the memory from List.

  @param[in] List               The pointer to LIST_ENTRY from
                                GetShellEnvVarList().

  @retval EFI_SUCCESS           The list was Set sucessfully.
**/
EFI_STATUS
SetEnvironmentVariableList(
  IN LIST_ENTRY *List
  );

/**
  sets all Shell-Guid-based environment variables.  this will
  also eliminate all pre-existing shell environment variables (even if they
  are not on the list).

  @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.

  @retval EFI_SUCCESS       The command executed successfully.
  @retval EFI_INVALID_PARAMETER The parameter is invalid.
  @retval EFI_OUT_OF_RESOURCES Out of resources.

  @sa SetEnvironmentVariableList
**/
EFI_STATUS
SetEnvironmentVariables(
  IN CONST CHAR16 **Environment
  );

/**
  free function for ENV_VAR_LIST objects.

  @param[in] List               The pointer to pointer to list.
**/
VOID
FreeEnvironmentVariableList(
  IN LIST_ENTRY *List
  );

/**
  Find an environment variable in the gShellEnvVarList.

  @param Key        The name of the environment variable.
  @param Value      The value of the environment variable, the buffer
                    shoule be freed by the caller.
  @param ValueSize  The size in bytes of the environment variable
                    including the tailing CHAR_NULL.
  @param Atts       The attributes of the variable.

  @retval EFI_SUCCESS       The command executed successfully.
  @retval EFI_NOT_FOUND     The environment variable is not found in
                            gShellEnvVarList.

**/
EFI_STATUS
ShellFindEnvVarInList (
  IN  CONST CHAR16    *Key,
  OUT CHAR16          **Value,
  OUT UINTN           *ValueSize,
  OUT UINT32          *Atts OPTIONAL
  );

/**
  Add an environment variable into gShellEnvVarList.

  @param Key        The name of the environment variable.
  @param Value      The value of environment variable.
  @param ValueSize  The size in bytes of the environment variable
                    including the tailing CHAR_NULL
  @param Atts       The attributes of the variable.

  @retval EFI_SUCCESS  The environment variable was added to list successfully.
  @retval others       Some errors happened.

**/
EFI_STATUS
ShellAddEnvVarToList (
  IN CONST CHAR16     *Key,
  IN CONST CHAR16     *Value,
  IN UINTN            ValueSize,
  IN UINT32           Atts
  );

/**
  Remove a specified environment variable in gShellEnvVarList.

  @param Key        The name of the environment variable.

  @retval EFI_SUCCESS       The command executed successfully.
  @retval EFI_NOT_FOUND     The environment variable is not found in
                            gShellEnvVarList.
**/
EFI_STATUS
ShellRemvoeEnvVarFromList (
  IN CONST CHAR16           *Key
  );

/**
  Initialize the gShellEnvVarList and cache all Shell-Guid-based environment 
  variables.
  
**/
EFI_STATUS
ShellInitEnvVarList (
  VOID
  );

/**
  Destructe the gShellEnvVarList.

**/
VOID
ShellFreeEnvVarList (
  VOID
  );

#endif //_SHELL_ENVIRONMENT_VARIABLE_HEADER_