ShellPkg : Cache the environment variable into memory to enhance

the performance.

Currently UEFI Shell reads variable storage to get the environment
variables every time running a new command. And reading(writing)
UEFI variables is a high cost operation on most platforms. In order
to enhance the performance this patch read the variable storage once
and cache the environment variables in memory. Every further 'set'
command will save the variable not only to Shell cache, but also the
flash variable storage.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Qiu Shumin <shumin.qiu@intel.com>
Reviewed-by: Jaben Carsey <jaben.carsey@intel.com>
Reviewed-by:Ruiyu Ni <ruiyu.ni@intel.com>

1 files changed, 58 insertions, 43 deletions

diff --git a/ShellPkg/Application/Shell/ShellProtocol.c b/ShellPkg/Application/Shell/ShellProtocol.c
index e55b5e9e0f..17c30029e4 100644
--- a/ShellPkg/Application/Shell/ShellProtocol.c
+++ b/ShellPkg/Application/Shell/ShellProtocol.c
@@ -2691,7 +2691,6 @@ EfiShellGetEnvEx(
   EFI_STATUS  Status;

   VOID        *Buffer;

   UINTN       Size;

-  LIST_ENTRY  List;

   ENV_VAR_LIST *Node;

   CHAR16      *CurrentWriteLocation;

 

@@ -2699,21 +2698,13 @@ EfiShellGetEnvEx(
   Buffer = NULL;

 

   if (Name == NULL) {

-    //

-    // Get all our environment variables

-    //

-    InitializeListHead(&List);

-    Status = GetEnvironmentVariableList(&List);

-    if (EFI_ERROR(Status)){

-      return (NULL);

-    }

 

     //

     // Build the semi-colon delimited list. (2 passes)

     //

-    for ( Node = (ENV_VAR_LIST*)GetFirstNode(&List)

-      ; !IsNull(&List, &Node->Link)

-      ; Node = (ENV_VAR_LIST*)GetNextNode(&List, &Node->Link)

+    for ( Node = (ENV_VAR_LIST*)GetFirstNode(&gShellEnvVarList.Link)

+      ; !IsNull(&gShellEnvVarList.Link, &Node->Link)

+      ; Node = (ENV_VAR_LIST*)GetNextNode(&gShellEnvVarList.Link, &Node->Link)

      ){

       ASSERT(Node->Key != NULL);

       Size += StrSize(Node->Key);

@@ -2723,16 +2714,13 @@ EfiShellGetEnvEx(
 

     Buffer = AllocateZeroPool(Size);

     if (Buffer == NULL) {

-      if (!IsListEmpty (&List)) {

-        FreeEnvironmentVariableList(&List);

-      }

       return (NULL);

     }

     CurrentWriteLocation = (CHAR16*)Buffer;

 

-    for ( Node = (ENV_VAR_LIST*)GetFirstNode(&List)

-      ; !IsNull(&List, &Node->Link)

-      ; Node = (ENV_VAR_LIST*)GetNextNode(&List, &Node->Link)

+    for ( Node = (ENV_VAR_LIST*)GetFirstNode(&gShellEnvVarList.Link)

+      ; !IsNull(&gShellEnvVarList.Link, &Node->Link)

+      ; Node = (ENV_VAR_LIST*)GetNextNode(&gShellEnvVarList.Link, &Node->Link)

      ){

       ASSERT(Node->Key != NULL);

       StrCpyS( CurrentWriteLocation, 

@@ -2742,37 +2730,43 @@ EfiShellGetEnvEx(
       CurrentWriteLocation += StrLen(CurrentWriteLocation) + 1;

     }

 

-    //

-    // Free the list...

-    //

-    if (!IsListEmpty (&List)) {

-      FreeEnvironmentVariableList(&List);

-    }

   } else {

     //

     // We are doing a specific environment variable

     //

+    Status = ShellFindEnvVarInList(Name, (CHAR16**)&Buffer, &Size, Attributes);

 

-    //

-    // get the size we need for this EnvVariable

-    //

-    Status = SHELL_GET_ENVIRONMENT_VARIABLE_AND_ATTRIBUTES(Name, Attributes, &Size, Buffer);

-    if (Status == EFI_BUFFER_TOO_SMALL) {

+    if (EFI_ERROR(Status)){

       //

-      // Allocate the space and recall the get function

+      // get the size we need for this EnvVariable

       //

-      Buffer = AllocateZeroPool(Size);

       Status = SHELL_GET_ENVIRONMENT_VARIABLE_AND_ATTRIBUTES(Name, Attributes, &Size, Buffer);

-    }

-    //

-    // we didnt get it (might not exist)

-    // free the memory if we allocated any and return NULL

-    //

-    if (EFI_ERROR(Status)) {

-      if (Buffer != NULL) {

-        FreePool(Buffer);

+      if (Status == EFI_BUFFER_TOO_SMALL) {

+        //

+        // Allocate the space and recall the get function

+        //

+        Buffer = AllocateZeroPool(Size);

+        Status = SHELL_GET_ENVIRONMENT_VARIABLE_AND_ATTRIBUTES(Name, Attributes, &Size, Buffer);

+      }

+      //

+      // we didnt get it (might not exist)

+      // free the memory if we allocated any and return NULL

+      //

+      if (EFI_ERROR(Status)) {

+        if (Buffer != NULL) {

+          FreePool(Buffer);

+        }

+        return (NULL);

+      } else {

+        //

+        // If we did not find the environment variable in the gShellEnvVarList

+        // but get it from UEFI variable storage successfully then we need update

+        // the gShellEnvVarList.

+        //

+        ShellFreeEnvVarList ();

+        Status = ShellInitEnvVarList ();

+        ASSERT (Status == EFI_SUCCESS);

       }

-      return (NULL);

     }

   }

 

@@ -2832,14 +2826,35 @@ InternalEfiShellSetEnv(
   IN BOOLEAN Volatile

   )

 {

+  EFI_STATUS      Status;

+  UINT32          Atts;

+

+  Atts = 0x0;

+  

   if (Value == NULL || StrLen(Value) == 0) {

-    return (SHELL_DELETE_ENVIRONMENT_VARIABLE(Name));

+    Status = SHELL_DELETE_ENVIRONMENT_VARIABLE(Name);

+    if (!EFI_ERROR(Status)) {

+      ShellRemvoeEnvVarFromList(Name);

+    }

+    return Status;

   } else {

     SHELL_DELETE_ENVIRONMENT_VARIABLE(Name);

     if (Volatile) {

-      return (SHELL_SET_ENVIRONMENT_VARIABLE_V(Name, StrSize(Value), Value));

+      Status = SHELL_SET_ENVIRONMENT_VARIABLE_V(Name, StrSize(Value), Value);

+      if (!EFI_ERROR(Status)) {

+        Atts   &= ~EFI_VARIABLE_NON_VOLATILE;

+        Atts   |= EFI_VARIABLE_BOOTSERVICE_ACCESS;

+        ShellAddEnvVarToList(Name, Value, StrSize(Value), Atts);

+      }

+      return Status;

     } else {

-      return (SHELL_SET_ENVIRONMENT_VARIABLE_NV(Name, StrSize(Value), Value));

+      Status = SHELL_SET_ENVIRONMENT_VARIABLE_NV(Name, StrSize(Value), Value);

+      if (!EFI_ERROR(Status)) {

+        Atts   |= EFI_VARIABLE_NON_VOLATILE;

+        Atts   |= EFI_VARIABLE_BOOTSERVICE_ACCESS;

+        ShellAddEnvVarToList(Name, Value, StrSize(Value), Atts);

+      } 

+      return Status;

     }

   }

 }