Re: [PATCH v2] MdeModulePkg/DebugLib: Print partial when format string is too long

["Gao, Liming" <liming.gao@intel.com>]

Reviewed-by: Liming Gao <liming.gao@intel.com>

>-----Original Message-----
>From: Ni, Ruiyu
>Sent: Monday, January 15, 2018 12:00 PM
>To: edk2-devel@lists.01.org
>Cc: Gao, Liming <liming.gao@intel.com>
>Subject: [PATCH v2] MdeModulePkg/DebugLib: Print partial when format
>string is too long
>
>Today's implementation prints nothing when the format string cannot
>fit in the report status extended data buffer.
>It confuses user.
>The patch changes to print partial message by truncating the format
>string when it's too long.
>
>The missing enhancement is the extended data buffer only reserves 96
>bytes for the var-args. When the format string is not very long but
>contains 13 %lx or %p, the var-args buffer is too small. Today's
>implementation prints nothing for this case.
>This patch doesn't change such behavior.
>
>Contributed-under: TianoCore Contribution Agreement 1.1
>Signed-off-by: Ruiyu Ni <ruiyu.ni@intel.com>
>Cc: Liming Gao <liming.gao@intel.com>
>---
> .../Library/PeiDxeDebugLibReportStatusCode/DebugLib.c         | 11 +++++++--
>--
> 1 file changed, 7 insertions(+), 4 deletions(-)
>
>diff --git
>a/MdeModulePkg/Library/PeiDxeDebugLibReportStatusCode/DebugLib.c
>b/MdeModulePkg/Library/PeiDxeDebugLibReportStatusCode/DebugLib.c
>index 163d530ae5..16a1d206fb 100644
>--- a/MdeModulePkg/Library/PeiDxeDebugLibReportStatusCode/DebugLib.c
>+++
>b/MdeModulePkg/Library/PeiDxeDebugLibReportStatusCode/DebugLib.c
>@@ -4,7 +4,7 @@
>   Note that if the debug message length is larger than the maximum allowable
>   record length, then the debug message will be ignored directly.
>
>-  Copyright (c) 2006 - 2015, Intel Corporation. All rights reserved.<BR>
>+  Copyright (c) 2006 - 2018, 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
>@@ -96,7 +96,7 @@ DebugPrint (
>   // If the TotalSize is larger than the maximum record size, then return
>   //
>   if (TotalSize > sizeof (Buffer)) {
>-    return;
>+    TotalSize = sizeof (Buffer);
>   }
>
>   //
>@@ -113,9 +113,12 @@ DebugPrint (
>   FormatString          = (CHAR8 *)((UINT64 *)(DebugInfo + 1) + 12);
>
>   //
>-  // Copy the Format string into the record
>+  // Copy the Format string into the record. It will be truncated if it's too long.
>   //
>-  AsciiStrCpyS (FormatString, sizeof(Buffer) - (4 + sizeof(EFI_DEBUG_INFO) +
>12 * sizeof(UINT64)), Format);
>+  AsciiStrnCpyS (
>+    FormatString, sizeof(Buffer) - (4 + sizeof(EFI_DEBUG_INFO) + 12 *
>sizeof(UINT64)),
>+    Format,       sizeof(Buffer) - (4 + sizeof(EFI_DEBUG_INFO) + 12 *
>sizeof(UINT64)) - 1
>+    );
>
>   //
>   // The first 12 * sizeof (UINT64) bytes following EFI_DEBUG_INFO are for
>variable arguments
>--
>2.15.1.windows.2