ShellPkg: stop using EFI_HANDLE in place of EFI_HII_HANDLE

The UefiShell*CommandsLib instances have constructor functions that do
something like:

  gHiiHandle = HiiAddPackages (...);
  ...
  ShellCommandRegisterCommandName (..., gHiiHandle, ...);

and destructor functions that implement the following pattern:

  HiiRemovePackages (gHiiHandle);

The -- semantic, not functional -- problem is that "gHiiHandle" is
declared with type EFI_HANDLE, and not EFI_HII_HANDLE, in all of these
library instances, even though HiiAddPackages() correctly returns
EFI_HII_HANDLE, and HiiRemovePackages() takes EFI_HII_HANDLE.

Once we fix the type of "gHiiHandle", it causes sort of a butterfly
effect, because it is passed around widely. Track down and update all of
those locations.

The DynamicCommand lib instances use a similar pattern, so they are
affected too.

NOTE: in practice, this patch is a no-op, as both EFI_HII_HANDLE and
EFI_HANDLE are typedefs to (VOID*). However, we shouldn't use EFI_HANDLE
where semantically EFI_HII_HANDLE is passed around.

Cc: Jaben Carsey <jaben.carsey@intel.com>
Cc: Ray Ni <ray.ni@intel.com>
Cc: Zhichao Gao <zhichao.gao@intel.com>
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Philippe Mathieu-Daude <philmd@redhat.com>
Reviewed-by: Zhichao Gao <zhichao.gao@intel.com>

25 files changed, 33 insertions, 33 deletions

diff --git a/ShellPkg/DynamicCommand/DpDynamicCommand/Dp.c b/ShellPkg/DynamicCommand/DpDynamicCommand/Dp.c
index 735cdcbcc0..4ec4c18348 100644
--- a/ShellPkg/DynamicCommand/DpDynamicCommand/Dp.c
+++ b/ShellPkg/DynamicCommand/DpDynamicCommand/Dp.c
@@ -36,7 +36,7 @@ typedef struct {
 

 #pragma pack()

 

-EFI_HANDLE   mDpHiiHandle;

+EFI_HII_HANDLE   mDpHiiHandle;

 

 typedef struct {

   EFI_HANDLE    Handle;

@@ -924,14 +924,14 @@ Done:
 

   @return HII handle.

 **/

-EFI_HANDLE

+EFI_HII_HANDLE

 InitializeHiiPackage (

   EFI_HANDLE                  ImageHandle

   )

 {

   EFI_STATUS                  Status;

   EFI_HII_PACKAGE_LIST_HEADER *PackageList;

-  EFI_HANDLE                  HiiHandle;

+  EFI_HII_HANDLE              HiiHandle;

 

   //

   // Retrieve HII package list from ImageHandle

diff --git a/ShellPkg/DynamicCommand/DpDynamicCommand/Dp.h b/ShellPkg/DynamicCommand/DpDynamicCommand/Dp.h
index 43aa4505ee..e446cccde9 100644
--- a/ShellPkg/DynamicCommand/DpDynamicCommand/Dp.h
+++ b/ShellPkg/DynamicCommand/DpDynamicCommand/Dp.h
@@ -36,7 +36,7 @@
 #include <Library/UefiHiiServicesLib.h>

 #include <Library/PerformanceLib.h>

 

-extern EFI_HANDLE mDpHiiHandle;

+extern EFI_HII_HANDLE mDpHiiHandle;

 

 #define DP_MAJOR_VERSION        2

 #define DP_MINOR_VERSION        5

@@ -133,7 +133,7 @@ RunDp (
 

   @return HII handle.

 **/

-EFI_HANDLE

+EFI_HII_HANDLE

 InitializeHiiPackage (

   EFI_HANDLE                  ImageHandle

   );

diff --git a/ShellPkg/DynamicCommand/TftpDynamicCommand/Tftp.c b/ShellPkg/DynamicCommand/TftpDynamicCommand/Tftp.c
index 607899032e..f28da9af72 100644
--- a/ShellPkg/DynamicCommand/TftpDynamicCommand/Tftp.c
+++ b/ShellPkg/DynamicCommand/TftpDynamicCommand/Tftp.c
@@ -11,7 +11,7 @@
 #include "Tftp.h"

 

 #define IP4_CONFIG2_INTERFACE_INFO_NAME_LENGTH 32

-EFI_HANDLE   mTftpHiiHandle;

+EFI_HII_HANDLE   mTftpHiiHandle;

 

 /*

    Constant strings and definitions related to the message indicating the amount of

@@ -1087,14 +1087,14 @@ CheckPacket (
 

   @return HII handle.

 **/

-EFI_HANDLE

+EFI_HII_HANDLE

 InitializeHiiPackage (

   EFI_HANDLE                  ImageHandle

   )

 {

   EFI_STATUS                  Status;

   EFI_HII_PACKAGE_LIST_HEADER *PackageList;

-  EFI_HANDLE                  HiiHandle;

+  EFI_HII_HANDLE              HiiHandle;

 

   //

   // Retrieve HII package list from ImageHandle

diff --git a/ShellPkg/DynamicCommand/TftpDynamicCommand/Tftp.h b/ShellPkg/DynamicCommand/TftpDynamicCommand/Tftp.h
index 7a9ed4724e..4cd7784368 100644
--- a/ShellPkg/DynamicCommand/TftpDynamicCommand/Tftp.h
+++ b/ShellPkg/DynamicCommand/TftpDynamicCommand/Tftp.h
@@ -30,7 +30,7 @@
 #include <Library/PrintLib.h>

 #include <Library/UefiHiiServicesLib.h>

 

-extern EFI_HANDLE mTftpHiiHandle;

+extern EFI_HII_HANDLE mTftpHiiHandle;

 

 typedef struct {

   UINTN  FileSize;

@@ -62,7 +62,7 @@ RunTftp (
 

   @return HII handle.

 **/

-EFI_HANDLE

+EFI_HII_HANDLE

 InitializeHiiPackage (

   EFI_HANDLE                  ImageHandle

   );

diff --git a/ShellPkg/Include/Library/ShellCommandLib.h b/ShellPkg/Include/Library/ShellCommandLib.h
index 287bc0eba7..63fcac82a2 100644
--- a/ShellPkg/Include/Library/ShellCommandLib.h
+++ b/ShellPkg/Include/Library/ShellCommandLib.h
@@ -136,7 +136,7 @@ ShellCommandRegisterCommandName (
   IN        UINT32                      ShellMinSupportLevel,

   IN CONST  CHAR16                      *ProfileName,

   IN CONST  BOOLEAN                     CanAffectLE,

-  IN CONST  EFI_HANDLE                  HiiHandle,

+  IN CONST  EFI_HII_HANDLE              HiiHandle,

   IN CONST  EFI_STRING_ID               ManFormatHelp

   );

 

diff --git a/ShellPkg/Include/Library/ShellLib.h b/ShellPkg/Include/Library/ShellLib.h
index 31594796cd..1dc41f2cc1 100644
--- a/ShellPkg/Include/Library/ShellLib.h
+++ b/ShellPkg/Include/Library/ShellLib.h
@@ -965,7 +965,7 @@ ShellPrintHiiEx(
   IN INT32                Row OPTIONAL,

   IN CONST CHAR8          *Language OPTIONAL,

   IN CONST EFI_STRING_ID  HiiFormatStringId,

-  IN CONST EFI_HANDLE     HiiFormatHandle,

+  IN CONST EFI_HII_HANDLE HiiFormatHandle,

   ...

   );

 

@@ -1260,7 +1260,7 @@ EFIAPI
 ShellPromptForResponseHii (

   IN SHELL_PROMPT_REQUEST_TYPE         Type,

   IN CONST EFI_STRING_ID  HiiFormatStringId,

-  IN CONST EFI_HANDLE     HiiFormatHandle,

+  IN CONST EFI_HII_HANDLE HiiFormatHandle,

   IN OUT VOID             **Response

   );

 

diff --git a/ShellPkg/Library/UefiHandleParsingLib/UefiHandleParsingLib.c b/ShellPkg/Library/UefiHandleParsingLib/UefiHandleParsingLib.c
index f179c41092..f62d30ef67 100644
--- a/ShellPkg/Library/UefiHandleParsingLib/UefiHandleParsingLib.c
+++ b/ShellPkg/Library/UefiHandleParsingLib/UefiHandleParsingLib.c
@@ -14,7 +14,7 @@
 #include <PiDxe.h>

 #include <Protocol/FirmwareVolume2.h>

 

-EFI_HANDLE        mHandleParsingHiiHandle = NULL;

+EFI_HII_HANDLE    mHandleParsingHiiHandle = NULL;

 HANDLE_INDEX_LIST mHandleList = {{{NULL,NULL},0,0},0};

 GUID_INFO_BLOCK   *mGuidList;

 UINTN             mGuidListCount;

diff --git a/ShellPkg/Library/UefiShellBcfgCommandLib/UefiShellBcfgCommandLib.c b/ShellPkg/Library/UefiShellBcfgCommandLib/UefiShellBcfgCommandLib.c
index e8b48b4990..f8bcaebe46 100644
--- a/ShellPkg/Library/UefiShellBcfgCommandLib/UefiShellBcfgCommandLib.c
+++ b/ShellPkg/Library/UefiShellBcfgCommandLib/UefiShellBcfgCommandLib.c
@@ -38,7 +38,7 @@
 #include <Library/UefiBootManagerLib.h>

 

 STATIC CONST CHAR16 mFileName[] = L"ShellCommands";

-STATIC EFI_HANDLE gShellBcfgHiiHandle  = NULL;

+STATIC EFI_HII_HANDLE gShellBcfgHiiHandle  = NULL;

 

 typedef enum {

   BcfgTargetBootOrder    = 0,

diff --git a/ShellPkg/Library/UefiShellCommandLib/UefiShellCommandLib.c b/ShellPkg/Library/UefiShellCommandLib/UefiShellCommandLib.c
index 826ced30a8..4c48b65fbc 100644
--- a/ShellPkg/Library/UefiShellCommandLib/UefiShellCommandLib.c
+++ b/ShellPkg/Library/UefiShellCommandLib/UefiShellCommandLib.c
@@ -554,7 +554,7 @@ ShellCommandRegisterCommandName (
   IN        UINT32                      ShellMinSupportLevel,

   IN CONST  CHAR16                      *ProfileName,

   IN CONST  BOOLEAN                     CanAffectLE,

-  IN CONST  EFI_HANDLE                  HiiHandle,

+  IN CONST  EFI_HII_HANDLE              HiiHandle,

   IN CONST  EFI_STRING_ID               ManFormatHelp

   )

 {

diff --git a/ShellPkg/Library/UefiShellCommandLib/UefiShellCommandLib.h b/ShellPkg/Library/UefiShellCommandLib/UefiShellCommandLib.h
index 36fe628a8c..8ecc2f6bf5 100644
--- a/ShellPkg/Library/UefiShellCommandLib/UefiShellCommandLib.h
+++ b/ShellPkg/Library/UefiShellCommandLib/UefiShellCommandLib.h
@@ -46,7 +46,7 @@ typedef struct{
   SHELL_GET_MAN_FILENAME      GetManFileName;

   SHELL_RUN_COMMAND           CommandHandler;

   BOOLEAN                     LastError;

-  EFI_HANDLE                  HiiHandle;

+  EFI_HII_HANDLE              HiiHandle;

   EFI_STRING_ID               ManFormatHelp;

 } SHELL_COMMAND_INTERNAL_LIST_ENTRY;

 

diff --git a/ShellPkg/Library/UefiShellDebug1CommandsLib/UefiShellDebug1CommandsLib.c b/ShellPkg/Library/UefiShellDebug1CommandsLib/UefiShellDebug1CommandsLib.c
index ddce3bef5a..f918867f47 100644
--- a/ShellPkg/Library/UefiShellDebug1CommandsLib/UefiShellDebug1CommandsLib.c
+++ b/ShellPkg/Library/UefiShellDebug1CommandsLib/UefiShellDebug1CommandsLib.c
@@ -10,7 +10,7 @@
 #include <Library/BcfgCommandLib.h>

 

 STATIC CONST CHAR16 mFileName[] = L"Debug1Commands";

-EFI_HANDLE gShellDebug1HiiHandle = NULL;

+EFI_HII_HANDLE gShellDebug1HiiHandle = NULL;

 

 /**

   Gets the debug file name.  This will be used if HII is not working.

diff --git a/ShellPkg/Library/UefiShellDebug1CommandsLib/UefiShellDebug1CommandsLib.h b/ShellPkg/Library/UefiShellDebug1CommandsLib/UefiShellDebug1CommandsLib.h
index 32a933b9f0..082d488cb2 100644
--- a/ShellPkg/Library/UefiShellDebug1CommandsLib/UefiShellDebug1CommandsLib.h
+++ b/ShellPkg/Library/UefiShellDebug1CommandsLib/UefiShellDebug1CommandsLib.h
@@ -52,7 +52,7 @@
 #include <Library/HandleParsingLib.h>

 

 

-extern        EFI_HANDLE                        gShellDebug1HiiHandle;

+extern        EFI_HII_HANDLE                    gShellDebug1HiiHandle;

 

 /**

   Function returns a system configuration table that is stored in the

diff --git a/ShellPkg/Library/UefiShellDriver1CommandsLib/UefiShellDriver1CommandsLib.c b/ShellPkg/Library/UefiShellDriver1CommandsLib/UefiShellDriver1CommandsLib.c
index 4a05fa9942..e2219c62ec 100644
--- a/ShellPkg/Library/UefiShellDriver1CommandsLib/UefiShellDriver1CommandsLib.c
+++ b/ShellPkg/Library/UefiShellDriver1CommandsLib/UefiShellDriver1CommandsLib.c
@@ -9,7 +9,7 @@
 #include "UefiShellDriver1CommandsLib.h"

 

 STATIC CONST CHAR16 mFileName[] = L"Driver1Commands";

-EFI_HANDLE gShellDriver1HiiHandle = NULL;

+EFI_HII_HANDLE gShellDriver1HiiHandle = NULL;

 BOOLEAN    gInReconnect = FALSE;

 

 /**

diff --git a/ShellPkg/Library/UefiShellDriver1CommandsLib/UefiShellDriver1CommandsLib.h b/ShellPkg/Library/UefiShellDriver1CommandsLib/UefiShellDriver1CommandsLib.h
index 7e0b8b0940..ee795c4ce0 100644
--- a/ShellPkg/Library/UefiShellDriver1CommandsLib/UefiShellDriver1CommandsLib.h
+++ b/ShellPkg/Library/UefiShellDriver1CommandsLib/UefiShellDriver1CommandsLib.h
@@ -58,7 +58,7 @@
 #include <Library/HandleParsingLib.h>

 

 

-extern        EFI_HANDLE                        gShellDriver1HiiHandle;

+extern        EFI_HII_HANDLE                    gShellDriver1HiiHandle;

 extern        BOOLEAN                           gInReconnect;

 

 /**

diff --git a/ShellPkg/Library/UefiShellLevel1CommandsLib/UefiShellLevel1CommandsLib.c b/ShellPkg/Library/UefiShellLevel1CommandsLib/UefiShellLevel1CommandsLib.c
index ecbee99e3b..88cddd88dd 100644
--- a/ShellPkg/Library/UefiShellLevel1CommandsLib/UefiShellLevel1CommandsLib.c
+++ b/ShellPkg/Library/UefiShellLevel1CommandsLib/UefiShellLevel1CommandsLib.c
@@ -10,7 +10,7 @@
 #include "UefiShellLevel1CommandsLib.h"

 

 STATIC CONST CHAR16 mFileName[] = L"ShellCommands";

-EFI_HANDLE gShellLevel1HiiHandle = NULL;

+EFI_HII_HANDLE gShellLevel1HiiHandle = NULL;

 

 /**

   Return the help text filename.  Only used if no HII information found.

diff --git a/ShellPkg/Library/UefiShellLevel1CommandsLib/UefiShellLevel1CommandsLib.h b/ShellPkg/Library/UefiShellLevel1CommandsLib/UefiShellLevel1CommandsLib.h
index 55acdd2b1f..f2f9cc5dcf 100644
--- a/ShellPkg/Library/UefiShellLevel1CommandsLib/UefiShellLevel1CommandsLib.h
+++ b/ShellPkg/Library/UefiShellLevel1CommandsLib/UefiShellLevel1CommandsLib.h
@@ -33,7 +33,7 @@
 #include <Library/HiiLib.h>

 #include <Library/FileHandleLib.h>

 

-extern        EFI_HANDLE                        gShellLevel1HiiHandle;

+extern        EFI_HII_HANDLE                    gShellLevel1HiiHandle;

 

 /**

   Function for 'stall' command.

diff --git a/ShellPkg/Library/UefiShellLevel2CommandsLib/UefiShellLevel2CommandsLib.c b/ShellPkg/Library/UefiShellLevel2CommandsLib/UefiShellLevel2CommandsLib.c
index c2a0bb492f..69427637bb 100644
--- a/ShellPkg/Library/UefiShellLevel2CommandsLib/UefiShellLevel2CommandsLib.c
+++ b/ShellPkg/Library/UefiShellLevel2CommandsLib/UefiShellLevel2CommandsLib.c
@@ -29,7 +29,7 @@
 #include "UefiShellLevel2CommandsLib.h"

 

 CONST CHAR16 mFileName[] = L"ShellCommands";

-EFI_HANDLE gShellLevel2HiiHandle = NULL;

+EFI_HII_HANDLE gShellLevel2HiiHandle = NULL;

 

 /**

   Get the filename to get help text from if not using HII.

diff --git a/ShellPkg/Library/UefiShellLevel2CommandsLib/UefiShellLevel2CommandsLib.h b/ShellPkg/Library/UefiShellLevel2CommandsLib/UefiShellLevel2CommandsLib.h
index 6d522d4bb4..77be6f1a12 100644
--- a/ShellPkg/Library/UefiShellLevel2CommandsLib/UefiShellLevel2CommandsLib.h
+++ b/ShellPkg/Library/UefiShellLevel2CommandsLib/UefiShellLevel2CommandsLib.h
@@ -43,7 +43,7 @@
 #include <Library/FileHandleLib.h>

 

 extern CONST  CHAR16                            mFileName[];

-extern        EFI_HANDLE                        gShellLevel2HiiHandle;

+extern        EFI_HII_HANDLE                    gShellLevel2HiiHandle;

 

 /**

   Function for 'attrib' command.

diff --git a/ShellPkg/Library/UefiShellLevel3CommandsLib/UefiShellLevel3CommandsLib.c b/ShellPkg/Library/UefiShellLevel3CommandsLib/UefiShellLevel3CommandsLib.c
index 7d2cc4a483..ce4afd117a 100644
--- a/ShellPkg/Library/UefiShellLevel3CommandsLib/UefiShellLevel3CommandsLib.c
+++ b/ShellPkg/Library/UefiShellLevel3CommandsLib/UefiShellLevel3CommandsLib.c
@@ -9,7 +9,7 @@
 #include "UefiShellLevel3CommandsLib.h"

 

 CONST CHAR16 gShellLevel3FileName[] = L"ShellCommands";

-EFI_HANDLE gShellLevel3HiiHandle = NULL;

+EFI_HII_HANDLE gShellLevel3HiiHandle = NULL;

 

 /**

   return the filename to get help from is not using HII.

diff --git a/ShellPkg/Library/UefiShellLevel3CommandsLib/UefiShellLevel3CommandsLib.h b/ShellPkg/Library/UefiShellLevel3CommandsLib/UefiShellLevel3CommandsLib.h
index 2d97ae4d3c..c095b9275e 100644
--- a/ShellPkg/Library/UefiShellLevel3CommandsLib/UefiShellLevel3CommandsLib.h
+++ b/ShellPkg/Library/UefiShellLevel3CommandsLib/UefiShellLevel3CommandsLib.h
@@ -32,7 +32,7 @@
 #include <Library/HiiLib.h>

 #include <Library/FileHandleLib.h>

 

-extern EFI_HANDLE gShellLevel3HiiHandle;

+extern EFI_HII_HANDLE gShellLevel3HiiHandle;

 

 /**

   Function for 'type' command.

diff --git a/ShellPkg/Library/UefiShellLib/UefiShellLib.c b/ShellPkg/Library/UefiShellLib/UefiShellLib.c
index 5be530092e..835d0f88ca 100644
--- a/ShellPkg/Library/UefiShellLib/UefiShellLib.c
+++ b/ShellPkg/Library/UefiShellLib/UefiShellLib.c
@@ -2997,7 +2997,7 @@ ShellPrintHiiEx(
   IN INT32                Row OPTIONAL,

   IN CONST CHAR8          *Language OPTIONAL,

   IN CONST EFI_STRING_ID  HiiFormatStringId,

-  IN CONST EFI_HANDLE     HiiFormatHandle,

+  IN CONST EFI_HII_HANDLE HiiFormatHandle,

   ...

   )

 {

@@ -3609,7 +3609,7 @@ EFIAPI
 ShellPromptForResponseHii (

   IN SHELL_PROMPT_REQUEST_TYPE         Type,

   IN CONST EFI_STRING_ID  HiiFormatStringId,

-  IN CONST EFI_HANDLE     HiiFormatHandle,

+  IN CONST EFI_HII_HANDLE HiiFormatHandle,

   IN OUT VOID             **Response

   )

 {

diff --git a/ShellPkg/Library/UefiShellNetwork1CommandsLib/UefiShellNetwork1CommandsLib.c b/ShellPkg/Library/UefiShellNetwork1CommandsLib/UefiShellNetwork1CommandsLib.c
index 7e823cabd2..9a2b23fdc5 100644
--- a/ShellPkg/Library/UefiShellNetwork1CommandsLib/UefiShellNetwork1CommandsLib.c
+++ b/ShellPkg/Library/UefiShellNetwork1CommandsLib/UefiShellNetwork1CommandsLib.c
@@ -8,7 +8,7 @@
 #include "UefiShellNetwork1CommandsLib.h"

 

 CONST CHAR16 gShellNetwork1FileName[] = L"ShellCommands";

-EFI_HANDLE gShellNetwork1HiiHandle = NULL;

+EFI_HII_HANDLE gShellNetwork1HiiHandle = NULL;

 

 /**

   return the file name of the help text file if not using HII.

diff --git a/ShellPkg/Library/UefiShellNetwork1CommandsLib/UefiShellNetwork1CommandsLib.h b/ShellPkg/Library/UefiShellNetwork1CommandsLib/UefiShellNetwork1CommandsLib.h
index d4ed8c0465..fddada2efa 100644
--- a/ShellPkg/Library/UefiShellNetwork1CommandsLib/UefiShellNetwork1CommandsLib.h
+++ b/ShellPkg/Library/UefiShellNetwork1CommandsLib/UefiShellNetwork1CommandsLib.h
@@ -38,7 +38,7 @@
 #include <Library/DevicePathLib.h>

 #include <Library/PrintLib.h>

 

-extern EFI_HANDLE gShellNetwork1HiiHandle;

+extern EFI_HII_HANDLE gShellNetwork1HiiHandle;

 

 /**

   Function for 'ping' command.

diff --git a/ShellPkg/Library/UefiShellNetwork2CommandsLib/UefiShellNetwork2CommandsLib.c b/ShellPkg/Library/UefiShellNetwork2CommandsLib/UefiShellNetwork2CommandsLib.c
index 5a7ffbfa19..4aab4295c1 100644
--- a/ShellPkg/Library/UefiShellNetwork2CommandsLib/UefiShellNetwork2CommandsLib.c
+++ b/ShellPkg/Library/UefiShellNetwork2CommandsLib/UefiShellNetwork2CommandsLib.c
@@ -8,7 +8,7 @@
 #include "UefiShellNetwork2CommandsLib.h"

 

 CONST CHAR16 gShellNetwork2FileName[] = L"ShellCommands";

-EFI_HANDLE gShellNetwork2HiiHandle = NULL;

+EFI_HII_HANDLE gShellNetwork2HiiHandle = NULL;

 

 /**

   return the file name of the help text file if not using HII.

diff --git a/ShellPkg/Library/UefiShellNetwork2CommandsLib/UefiShellNetwork2CommandsLib.h b/ShellPkg/Library/UefiShellNetwork2CommandsLib/UefiShellNetwork2CommandsLib.h
index 9a5db32f2b..9ea42cf26d 100644
--- a/ShellPkg/Library/UefiShellNetwork2CommandsLib/UefiShellNetwork2CommandsLib.h
+++ b/ShellPkg/Library/UefiShellNetwork2CommandsLib/UefiShellNetwork2CommandsLib.h
@@ -27,7 +27,7 @@
 #include <Library/HiiLib.h>

 #include <Library/NetLib.h>

 

-extern EFI_HANDLE gShellNetwork2HiiHandle;

+extern EFI_HII_HANDLE gShellNetwork2HiiHandle;

 

 /**

   Function for 'ping6' command.