ShellPkg: Per UEFI Shell 2.2 SPEC to make Shell supports 'NoNesting'.

This patch makes Shell support -nonesting invocation option. This option
specifies that EFI_SHELL_PROTOCOL.Execute API nesting of a new Shell
instance is optional and dependent on the 'nonesting' Shell environment
variable.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Jaben Carsey <jaben.carsey@intel.com>
Reviewed-by: Qiu Shumin <shumin.qiu@intel.com>
Reviewed-by: Jim Dailey <Jim_Dailey@Dell.com>

ShellPkg/Application/Shell/Shell.c

@@ -1,7 +1,7 @@
 /** @file
   This is THE shell (application)
 
-  Copyright (c) 2009 - 2015, Intel Corporation. All rights reserved.<BR>
+  Copyright (c) 2009 - 2016, Intel Corporation. All rights reserved.<BR>
   (C) Copyright 2013-2014 Hewlett-Packard Development Company, L.P.<BR>
   This program and the accompanying materials
   are licensed and made available under the terms and conditions of the BSD License
@@ -33,6 +33,7 @@ SHELL_INFO ShellInfoObject = {
       0,
       0,
       0,
+      0,
       0
     }},
     0,
@@ -69,6 +70,9 @@ SHELL_INFO ShellInfoObject = {
 STATIC CONST CHAR16 mScriptExtension[]      = L".NSH";
 STATIC CONST CHAR16 mExecutableExtensions[] = L".NSH;.EFI";
 STATIC CONST CHAR16 mStartupScript[]        = L"startup.nsh";
+CONST CHAR16 mNoNestingEnvVarName[]         = L"nonesting";
+CONST CHAR16 mNoNestingTrue[]               = L"True";
+CONST CHAR16 mNoNestingFalse[]              = L"False";
 
 /**
   Cleans off leading and trailing spaces and tabs.
@@ -456,6 +460,29 @@ UefiMain (
       Status = ShellCommandCreateInitialMappingsAndPaths();
     }
 
+    //
+    // Set the environment variable for nesting support
+    //
+    Size = 0;
+    TempString = NULL;
+    if (!ShellInfoObject.ShellInitSettings.BitUnion.Bits.NoNest) {
+      //
+      // No change.  require nesting in Shell Protocol Execute()
+      //
+      StrnCatGrow(&TempString,
+                  &Size,
+                  L"False",
+                  0);
+    } else {
+      StrnCatGrow(&TempString,
+                  &Size,
+                  mNoNestingTrue,
+                  0);
+    }
+    Status = InternalEfiShellSetEnv(mNoNestingEnvVarName, TempString, TRUE);
+    SHELL_FREE_NON_NULL(TempString);
+    Size = 0;
+
     //
     // save the device path for the loaded image and the device path for the filepath (under loaded image)
     // These are where to look for the startup.nsh file
@@ -891,6 +918,7 @@ ProcessCommandLine(
   ShellInfoObject.ShellInitSettings.BitUnion.Bits.NoVersion    = FALSE;
   ShellInfoObject.ShellInitSettings.BitUnion.Bits.Delay        = FALSE;
   ShellInfoObject.ShellInitSettings.BitUnion.Bits.Exit         = FALSE;
+  ShellInfoObject.ShellInitSettings.BitUnion.Bits.NoNest       = FALSE;
   ShellInfoObject.ShellInitSettings.Delay = 5;
 
   //
@@ -950,6 +978,13 @@ ProcessCommandLine(
                                  ) == 0) {
       ShellInfoObject.ShellInitSettings.BitUnion.Bits.NoVersion    = TRUE;
     }
+    else if (UnicodeCollation->StriColl (
+                                 UnicodeCollation,
+                                 L"-nonest",
+                                 CurrentArg
+                                 ) == 0) {
+      ShellInfoObject.ShellInitSettings.BitUnion.Bits.NoNest       = TRUE;
+    }
     else if (UnicodeCollation->StriColl (
                                  UnicodeCollation,
                                  L"-delay",
@@ -1324,7 +1359,7 @@ AddLineToCommandHistory(
   BUFFER_LIST *Walker;
   UINT16       MaxHistoryCmdCount;
   UINT16       Count;
-  
+
   Count = 0;
   MaxHistoryCmdCount = PcdGet16(PcdShellMaxHistoryCommandCount);
   
@@ -2452,7 +2487,7 @@ SetupAndRunCommandOrFile(
   IN   CHAR16                         *CmdLine,
   IN   CHAR16                         *FirstParameter,
   IN   EFI_SHELL_PARAMETERS_PROTOCOL  *ParamProtocol,
-  OUT EFI_STATUS                    *CommandStatus
+  OUT EFI_STATUS                      *CommandStatus
 )
 {
   EFI_STATUS                Status;

ShellPkg/Application/Shell/Shell.h

@@ -58,6 +58,10 @@
 #include "ConsoleWrappers.h"
 #include "FileHandleWrappers.h"
 
+extern CONST CHAR16 mNoNestingEnvVarName[];
+extern CONST CHAR16 mNoNestingTrue[];
+extern CONST CHAR16 mNoNestingFalse[];
+
 typedef struct {
   LIST_ENTRY        Link;           ///< Standard linked list handler.
   SHELL_FILE_HANDLE *SplitStdOut;   ///< ConsoleOut for use in the split.
@@ -73,7 +77,8 @@ typedef struct {
   UINT32  NoMap:1;        ///< Was "-nomap"         found on command line.
   UINT32  NoVersion:1;    ///< Was "-noversion"     found on command line.
   UINT32  Delay:1;        ///< Was "-delay[:n]      found on command line
-  UINT32  Exit:1;         ///< Was "-_exit"          found on command line
+  UINT32  Exit:1;         ///< Was "-_exit"         found on command line
+  UINT32  NoNest:1;       ///< Was "-nonest"        found on command line
   UINT32  Reserved:7;     ///< Extra bits
 } SHELL_BITS;
 

ShellPkg/Application/Shell/ShellProtocol.c

@@ -3,7 +3,7 @@
   manipulation, and initialization of EFI_SHELL_PROTOCOL.
 
   (C) Copyright 2014 Hewlett-Packard Development Company, L.P.<BR>
-  Copyright (c) 2009 - 2015, Intel Corporation. All rights reserved.<BR>
+  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
@@ -1588,6 +1588,109 @@ FreeAlloc:
 
   return(Status);
 }
+
+/**
+  internal worker function to load and run an image in the current shell.
+
+  @param CommandLine            Points to the NULL-terminated UCS-2 encoded string
+                                containing the command line. If NULL then the command-
+                                line will be empty.
+  @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. If this
+                                is NULL, then the current shell environment is used.
+                
+  @param[out] StartImageStatus  Returned status from the command line.
+
+  @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.
+**/
+EFI_STATUS
+EFIAPI
+InternalShellExecute(
+  IN CONST CHAR16                   *CommandLine OPTIONAL,
+  IN CONST CHAR16                   **Environment OPTIONAL,
+  OUT EFI_STATUS                    *StartImageStatus OPTIONAL
+  )
+{
+  EFI_STATUS                    Status;
+  EFI_STATUS                    CleanupStatus;
+  LIST_ENTRY                    OrigEnvs;
+
+  InitializeListHead(&OrigEnvs);
+
+  //
+  // Save our current environment settings for later restoration if necessary
+  //
+  if (Environment != NULL) {
+    Status = GetEnvironmentVariableList(&OrigEnvs);
+    if (!EFI_ERROR(Status)) {
+      Status = SetEnvironmentVariables(Environment);
+    } else {
+      return Status;
+    }
+  }
+
+  Status = RunShellCommand(CommandLine, StartImageStatus);
+
+  // Restore environment variables
+  if (!IsListEmpty(&OrigEnvs)) {
+    CleanupStatus = SetEnvironmentVariableList(&OrigEnvs);
+    ASSERT_EFI_ERROR (CleanupStatus);
+  }
+
+  return(Status);
+}
+
+/**
+  Determine if the UEFI Shell is currently running with nesting enabled or disabled.
+
+  @retval FALSE   nesting is required
+  @retval other   nesting is enabled
+**/
+STATIC
+BOOLEAN
+EFIAPI
+NestingEnabled(
+)
+{
+  EFI_STATUS  Status;
+  CHAR16      *Temp;
+  CHAR16      *Temp2;
+  UINTN       TempSize;
+  BOOLEAN     RetVal;
+
+  RetVal = TRUE;
+  Temp   = NULL;
+  Temp2  = NULL;
+
+  if (ShellInfoObject.ShellInitSettings.BitUnion.Bits.NoNest) {
+    TempSize = 0;
+    Temp     = NULL;
+    Status = SHELL_GET_ENVIRONMENT_VARIABLE(mNoNestingEnvVarName, &TempSize, Temp);
+    if (Status == EFI_BUFFER_TOO_SMALL) {
+      Temp = AllocateZeroPool(TempSize + sizeof(CHAR16));
+      if (Temp != NULL) {
+        Status = SHELL_GET_ENVIRONMENT_VARIABLE(mNoNestingEnvVarName, &TempSize, Temp);
+      }
+    }
+    Temp2 = StrnCatGrow(&Temp2, NULL, mNoNestingTrue, 0);
+    if (Temp != NULL && Temp2 != NULL && StringNoCaseCompare(&Temp, &Temp2) == 0) {
+      //
+      // Use the no nesting method.
+      //
+      RetVal = FALSE;
+    }
+  }
+
+  SHELL_FREE_NON_NULL(Temp);
+  SHELL_FREE_NON_NULL(Temp2);
+  return (RetVal);
+}
+
 /**
   Execute the command line.
 
@@ -1611,7 +1714,7 @@ FreeAlloc:
                             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 StatusCode         Points to the status code returned by the command.
+  @param StatusCode         Points to the status code returned by the CommandLine.
 
   @retval EFI_SUCCESS       The command executed successfully. The  status code
                             returned by the command is pointed to by StatusCode.
@@ -1643,11 +1746,9 @@ EfiShellExecute(
     return (EFI_UNSUPPORTED);
   }
 
-  if (Environment != NULL) {
+  if (NestingEnabled()) {
-    // If Environment isn't null, load a new image of the shell with its own
-    // environment
     DevPath = AppendDevicePath (ShellInfoObject.ImageDevPath, ShellInfoObject.FileDevPath);
- 
+
     DEBUG_CODE_BEGIN();
     Temp = ConvertDevicePathToText(ShellInfoObject.FileDevPath, TRUE, TRUE);
     FreePool(Temp);
@@ -1676,19 +1777,10 @@ EfiShellExecute(
     FreePool(DevPath);
     FreePool(Temp);
   } else {
-    // If Environment is NULL, we are free to use and mutate the current shell
+    Status = InternalShellExecute(
-    // environment. This is much faster as uses much less memory.
+      (CONST CHAR16*)CommandLine,
-
+      (CONST CHAR16**)Environment,
-    if (CommandLine == NULL) {
+      StatusCode);
-      CommandLine = L"";
-    }
-
-    Status = RunShellCommand (CommandLine, &CalleeStatusCode);
-
-    // Pass up the command's exit code if the caller wants it
-    if (StatusCode != NULL) {
-      *StatusCode = (EFI_STATUS) CalleeStatusCode;
-    }
   }
 
   return(Status);
@@ -2814,6 +2906,11 @@ EfiShellSetEnv(
         gUnicodeCollation,
         (CHAR16*)Name,
         L"uefiversion") == 0
+    ||(!ShellInfoObject.ShellInitSettings.BitUnion.Bits.NoNest &&
+      gUnicodeCollation->StriColl(
+        gUnicodeCollation,
+        (CHAR16*)Name,
+        (CHAR16*)mNoNestingEnvVarName) == 0)
        ){
     return (EFI_INVALID_PARAMETER);
   }
@@ -2827,7 +2924,7 @@ EfiShellSetEnv(
   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).
-  
+
   Note that the current directory string should exclude the tailing backslash character.
 
   @param FileSystemMapping      A pointer to the file system mapping. If NULL,
@@ -2981,7 +3078,7 @@ EfiShellSetCurDir(
       ASSERT((MapListItem->CurrentDirectoryPath == NULL && Size == 0) || (MapListItem->CurrentDirectoryPath != NULL));
       if (MapListItem->CurrentDirectoryPath != NULL) {
         MapListItem->CurrentDirectoryPath[StrLen(MapListItem->CurrentDirectoryPath)-1] = CHAR_NULL;
-      }
+    }
     }
   } else {
     //