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

  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.

**/

#include "Shell.h"

#define INIT_NAME_BUFFER_SIZE  128
#define INIT_DATA_BUFFER_SIZE  1024

//
// The list is used to cache the environment variables.
//
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
  )
{
  EFI_STATUS  Status;
  UINTN       Size;
  VOID        *Buffer;
  UINT32      Attribs;

  ASSERT (Volatile != NULL);

  Size = 0;
  Buffer = NULL;

  //
  // get the variable
  //
  Status = gRT->GetVariable((CHAR16*)EnvVarName,
                            &gShellVariableGuid,
                            &Attribs,
                            &Size,
                            Buffer);
  if (Status == EFI_BUFFER_TOO_SMALL) {
    Buffer = AllocateZeroPool(Size);
    if (Buffer == NULL) {
      return EFI_OUT_OF_RESOURCES;
    }
    Status = gRT->GetVariable((CHAR16*)EnvVarName,
                              &gShellVariableGuid,
                              &Attribs,
                              &Size,
                              Buffer);
    FreePool(Buffer);
  }
  //
  // not found means volatile
  //
  if (Status == EFI_NOT_FOUND) {
    *Volatile = TRUE;
    return EFI_SUCCESS;
  }
  if (EFI_ERROR (Status)) {
    return Status;
  }

  //
  // check for the Non Volatile bit
  //
  *Volatile = !(BOOLEAN) ((Attribs & EFI_VARIABLE_NON_VOLATILE) == EFI_VARIABLE_NON_VOLATILE);
  return EFI_SUCCESS;
}

/**
  free function for ENV_VAR_LIST objects.

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

  ASSERT (List != NULL);
  if (List == NULL) {
    return;
  }

  for ( Node = (ENV_VAR_LIST*)GetFirstNode(List)
      ; !IsListEmpty(List)
      ; Node = (ENV_VAR_LIST*)GetFirstNode(List)
     ){
    ASSERT(Node != NULL);
    RemoveEntryList(&Node->Link);
    if (Node->Key != NULL) {
      FreePool(Node->Key);
    }
    if (Node->Val != NULL) {
      FreePool(Node->Val);
    }
    FreePool(Node);
  }
}

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

  @param[in, out] ListHead       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 *ListHead
  )
{
  CHAR16            *VariableName;
  UINTN             NameSize;
  UINTN             NameBufferSize;
  EFI_STATUS        Status;
  EFI_GUID          Guid;
  UINTN             ValSize;
  UINTN             ValBufferSize;
  ENV_VAR_LIST      *VarList;

  if (ListHead == NULL) {
    return (EFI_INVALID_PARAMETER);
  }
  
  Status = EFI_SUCCESS;
  
  ValBufferSize = INIT_DATA_BUFFER_SIZE;
  NameBufferSize = INIT_NAME_BUFFER_SIZE;
  VariableName = AllocateZeroPool(NameBufferSize);
  if (VariableName == NULL) {
    return (EFI_OUT_OF_RESOURCES);
  }
  *VariableName = CHAR_NULL;

  while (!EFI_ERROR(Status)) {
    NameSize = NameBufferSize;
    Status = gRT->GetNextVariableName(&NameSize, VariableName, &Guid);
    if (Status == EFI_NOT_FOUND){
      Status = EFI_SUCCESS;
      break;
    } else if (Status == EFI_BUFFER_TOO_SMALL) {
      NameBufferSize = NameSize > NameBufferSize * 2 ? NameSize : NameBufferSize * 2;
      SHELL_FREE_NON_NULL(VariableName);
      VariableName = AllocateZeroPool(NameBufferSize);
      if (VariableName == NULL) {
        Status = EFI_OUT_OF_RESOURCES;
        break;
      }
      NameSize = NameBufferSize;
      Status = gRT->GetNextVariableName(&NameSize, VariableName, &Guid);
    }
    
    if (!EFI_ERROR(Status) && CompareGuid(&Guid, &gShellVariableGuid)){
      VarList = AllocateZeroPool(sizeof(ENV_VAR_LIST));
      if (VarList == NULL) {
        Status = EFI_OUT_OF_RESOURCES;
      } else {
        ValSize = ValBufferSize;
        //
        // We need another CHAR16 to save '\0' in VarList->Val.
        //
        VarList->Val = AllocateZeroPool (ValSize + sizeof (CHAR16));
        if (VarList->Val == NULL) {
            SHELL_FREE_NON_NULL(VarList);
            Status = EFI_OUT_OF_RESOURCES;
            break;
        }
        Status = SHELL_GET_ENVIRONMENT_VARIABLE_AND_ATTRIBUTES(VariableName, &VarList->Atts, &ValSize, VarList->Val);
        if (Status == EFI_BUFFER_TOO_SMALL){
          ValBufferSize = ValSize > ValBufferSize * 2 ? ValSize : ValBufferSize * 2;
          SHELL_FREE_NON_NULL (VarList->Val);
          //
          // We need another CHAR16 to save '\0' in VarList->Val.
          //
          VarList->Val = AllocateZeroPool (ValBufferSize + sizeof (CHAR16));
          if (VarList->Val == NULL) {
            SHELL_FREE_NON_NULL(VarList);
            Status = EFI_OUT_OF_RESOURCES;
            break;
          }
          
          ValSize = ValBufferSize;
          Status = SHELL_GET_ENVIRONMENT_VARIABLE_AND_ATTRIBUTES(VariableName, &VarList->Atts, &ValSize, VarList->Val);
        }
        if (!EFI_ERROR(Status)) {
          VarList->Key = AllocateCopyPool(StrSize(VariableName), VariableName);
          if (VarList->Key == NULL) {
            SHELL_FREE_NON_NULL(VarList->Val);
            SHELL_FREE_NON_NULL(VarList);
            Status = EFI_OUT_OF_RESOURCES;
          } else {
            InsertTailList(ListHead, &VarList->Link);
          }
        } else {
          SHELL_FREE_NON_NULL(VarList->Val);
          SHELL_FREE_NON_NULL(VarList);
        }
      } // if (VarList == NULL) ... else ...
    } // compare guid
  } // while
  SHELL_FREE_NON_NULL (VariableName);

  if (EFI_ERROR(Status)) {
    FreeEnvironmentVariableList(ListHead);
  }

  return (Status);
}

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

  This function will also deallocate the memory from List.

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

  @retval EFI_SUCCESS           the list was Set sucessfully.
**/
EFI_STATUS
SetEnvironmentVariableList(
  IN LIST_ENTRY *ListHead
  )
{
  ENV_VAR_LIST      VarList;
  ENV_VAR_LIST      *Node;
  EFI_STATUS        Status;
  UINTN             Size;

  InitializeListHead(&VarList.Link);

  //
  // Delete all the current environment variables
  //
  Status = GetEnvironmentVariableList(&VarList.Link);
  ASSERT_EFI_ERROR(Status);

  for ( Node = (ENV_VAR_LIST*)GetFirstNode(&VarList.Link)
      ; !IsNull(&VarList.Link, &Node->Link)
      ; Node = (ENV_VAR_LIST*)GetNextNode(&VarList.Link, &Node->Link)
     ){
    if (Node->Key != NULL) {
      Status = SHELL_DELETE_ENVIRONMENT_VARIABLE(Node->Key);
    }
    ASSERT_EFI_ERROR(Status);
  }

  FreeEnvironmentVariableList(&VarList.Link);

  //
  // set all the variables fron the list
  //
  for ( Node = (ENV_VAR_LIST*)GetFirstNode(ListHead)
      ; !IsNull(ListHead, &Node->Link)
      ; Node = (ENV_VAR_LIST*)GetNextNode(ListHead, &Node->Link)
     ){
    Size = StrSize (Node->Val) - sizeof (CHAR16);
    if (Node->Atts & EFI_VARIABLE_NON_VOLATILE) {
      Status = SHELL_SET_ENVIRONMENT_VARIABLE_NV(Node->Key, Size, Node->Val);
    } else {
      Status = SHELL_SET_ENVIRONMENT_VARIABLE_V (Node->Key, Size, Node->Val);
    }
    ASSERT_EFI_ERROR(Status);
  }
  FreeEnvironmentVariableList(ListHead);

  return (Status);
}

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

  @param 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
  )
{
  CONST CHAR16  *CurrentString;
  UINTN         CurrentCount;
  ENV_VAR_LIST  *VarList;
  ENV_VAR_LIST  *Node;

  VarList = NULL;

  if (Environment == NULL) {
    return (EFI_INVALID_PARAMETER);
  }

  //
  // Build a list identical to the ones used for get/set list functions above
  //
  for ( CurrentCount = 0
      ;
      ; CurrentCount++
     ){
    CurrentString = Environment[CurrentCount];
    if (CurrentString == NULL) {
      break;
    }
    ASSERT(StrStr(CurrentString, L"=") != NULL);
    Node = AllocateZeroPool(sizeof(ENV_VAR_LIST));
    if (Node == NULL) {
      SetEnvironmentVariableList(&VarList->Link);
      return (EFI_OUT_OF_RESOURCES);
    }

    Node->Key = AllocateZeroPool((StrStr(CurrentString, L"=") - CurrentString + 1) * sizeof(CHAR16));
    if (Node->Key == NULL) {
      SHELL_FREE_NON_NULL(Node);
      SetEnvironmentVariableList(&VarList->Link);
      return (EFI_OUT_OF_RESOURCES);
    }

    //
    // Copy the string into the Key, leaving the last character allocated as NULL to terminate
    //
    StrnCpyS( Node->Key, 
              StrStr(CurrentString, L"=") - CurrentString + 1, 
              CurrentString,
              StrStr(CurrentString, L"=") - CurrentString
              );

    //
    // ValueSize = TotalSize - already removed size - size for '=' + size for terminator (the last 2 items cancel each other)
    //
    Node->Val = AllocateCopyPool(StrSize(CurrentString) - StrSize(Node->Key), CurrentString + StrLen(Node->Key) + 1);
    if (Node->Val == NULL) {
      SHELL_FREE_NON_NULL(Node->Key);
      SHELL_FREE_NON_NULL(Node);
      SetEnvironmentVariableList(&VarList->Link);
      return (EFI_OUT_OF_RESOURCES);
    }

    Node->Atts = EFI_VARIABLE_BOOTSERVICE_ACCESS;

    if (VarList == NULL) {
      VarList = AllocateZeroPool(sizeof(ENV_VAR_LIST));
      if (VarList == NULL) {
        SHELL_FREE_NON_NULL(Node->Key);
        SHELL_FREE_NON_NULL(Node->Val);
        SHELL_FREE_NON_NULL(Node);
        return (EFI_OUT_OF_RESOURCES);
      }
      InitializeListHead(&VarList->Link);
    }
    InsertTailList(&VarList->Link, &Node->Link);

  } // for loop

  //
  // set this new list as the set of all environment variables.
  // this function also frees the memory and deletes all pre-existing
  // shell-guid based environment variables.
  //
  return (SetEnvironmentVariableList(&VarList->Link));
}

/**
  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_NELL.
  @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
  )
{
  ENV_VAR_LIST      *Node;
  
  if (Key == NULL || Value == NULL || ValueSize == NULL) {
    return SHELL_INVALID_PARAMETER;
  }

  for ( Node = (ENV_VAR_LIST*)GetFirstNode(&gShellEnvVarList.Link)
      ; !IsNull(&gShellEnvVarList.Link, &Node->Link)
      ; Node = (ENV_VAR_LIST*)GetNextNode(&gShellEnvVarList.Link, &Node->Link)
     ){
    if (Node->Key != NULL && StrCmp(Key, Node->Key) == 0) {
      *Value      = AllocateCopyPool(StrSize(Node->Val), Node->Val);
      *ValueSize  = StrSize(Node->Val);
      if (Atts != NULL) {
        *Atts = Node->Atts;
      }
      return EFI_SUCCESS;
    }
  }

  return EFI_NOT_FOUND;
}

/**
  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
  )
{
  ENV_VAR_LIST      *Node;
  CHAR16            *LocalKey;
  CHAR16            *LocalValue;
  
  if (Key == NULL || Value == NULL || ValueSize == 0) {
    return EFI_INVALID_PARAMETER;
  }

  LocalValue = AllocateCopyPool (ValueSize, Value);
  if (LocalValue == NULL) {
    return EFI_OUT_OF_RESOURCES;
  }

  //
  // Update the variable value if it exists in gShellEnvVarList.
  //
  for ( Node = (ENV_VAR_LIST*)GetFirstNode(&gShellEnvVarList.Link)
      ; !IsNull(&gShellEnvVarList.Link, &Node->Link)
      ; Node = (ENV_VAR_LIST*)GetNextNode(&gShellEnvVarList.Link, &Node->Link)
     ){
    if (Node->Key != NULL && StrCmp(Key, Node->Key) == 0) {
      Node->Atts = Atts;
      SHELL_FREE_NON_NULL(Node->Val);
      Node->Val  = LocalValue;
      return EFI_SUCCESS;
    }
  }

  //
  // If the environment varialbe key doesn't exist in list just insert
  // a new node.
  //
  LocalKey = AllocateCopyPool (StrSize(Key), Key);
  if (LocalKey == NULL) {
    FreePool (LocalValue);
    return EFI_OUT_OF_RESOURCES;
  }
  Node = (ENV_VAR_LIST*)AllocateZeroPool (sizeof(ENV_VAR_LIST));
  if (Node == NULL) {
    FreePool (LocalKey);
    FreePool (LocalValue);
    return EFI_OUT_OF_RESOURCES;
  }
  Node->Key = LocalKey;
  Node->Val = LocalValue;
  Node->Atts = Atts;
  InsertTailList(&gShellEnvVarList.Link, &Node->Link);

  return EFI_SUCCESS;
}

/**
  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
  )
{
  ENV_VAR_LIST      *Node;

  if (Key == NULL) {
    return EFI_INVALID_PARAMETER;
  }

  for ( Node = (ENV_VAR_LIST*)GetFirstNode(&gShellEnvVarList.Link)
      ; !IsNull(&gShellEnvVarList.Link, &Node->Link)
      ; Node = (ENV_VAR_LIST*)GetNextNode(&gShellEnvVarList.Link, &Node->Link)
     ){
    if (Node->Key != NULL && StrCmp(Key, Node->Key) == 0) {
      SHELL_FREE_NON_NULL(Node->Key);
      SHELL_FREE_NON_NULL(Node->Val);
      RemoveEntryList(&Node->Link);
      SHELL_FREE_NON_NULL(Node);
      return EFI_SUCCESS;
    }
  }

  return EFI_NOT_FOUND;
}

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

  InitializeListHead(&gShellEnvVarList.Link);
  Status = GetEnvironmentVariableList (&gShellEnvVarList.Link);

  return Status;
}

/**
  Destructe the gShellEnvVarList.

**/
VOID
ShellFreeEnvVarList (
  VOID
  )
{
  FreeEnvironmentVariableList (&gShellEnvVarList.Link);
  InitializeListHead(&gShellEnvVarList.Link);

  return;
}