From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 9FFDE2095D20B for ; Sun, 25 Jun 2017 22:39:55 -0700 (PDT) Received: from orsmga002.jf.intel.com ([10.7.209.21]) by fmsmga103.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 25 Jun 2017 22:41:24 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.39,394,1493708400"; d="scan'208";a="103615997" Received: from fmsmsx103.amr.corp.intel.com ([10.18.124.201]) by orsmga002.jf.intel.com with ESMTP; 25 Jun 2017 22:41:23 -0700 Received: from fmsmsx155.amr.corp.intel.com (10.18.116.71) by FMSMSX103.amr.corp.intel.com (10.18.124.201) with Microsoft SMTP Server (TLS) id 14.3.319.2; Sun, 25 Jun 2017 22:41:23 -0700 Received: from shsmsx101.ccr.corp.intel.com (10.239.4.153) by FMSMSX155.amr.corp.intel.com (10.18.116.71) with Microsoft SMTP Server (TLS) id 14.3.319.2; Sun, 25 Jun 2017 22:41:23 -0700 Received: from shsmsx102.ccr.corp.intel.com ([169.254.2.146]) by SHSMSX101.ccr.corp.intel.com ([169.254.1.197]) with mapi id 14.03.0319.002; Mon, 26 Jun 2017 13:41:20 +0800 From: "Zeng, Star" To: "Ni, Ruiyu" , "edk2-devel@lists.01.org" CC: "Gao, Liming" , "Zeng, Star" Thread-Topic: [PATCH V2 3/3] DuetPkg FsVariable: Update GetNextVariableName to follow UEFI 2.7 Thread-Index: AQHS6/fkhgduWBrMm0+q6tMuxOxLcqIxlQAAgACYeJCAAJHcgIADt4gA//+nhQCAAIaIUA== Date: Mon, 26 Jun 2017 05:41:20 +0000 Message-ID: <0C09AFA07DD0434D9E2A0C6AEB0483103B8ED40B@shsmsx102.ccr.corp.intel.com> References: <1498205290-157888-1-git-send-email-star.zeng@intel.com> <1498205290-157888-4-git-send-email-star.zeng@intel.com> <734D49CCEBEEF84792F5B80ED585239D5B9A1821@SHSMSX104.ccr.corp.intel.com> <0C09AFA07DD0434D9E2A0C6AEB0483103B8ECCF8@shsmsx102.ccr.corp.intel.com> <734D49CCEBEEF84792F5B80ED585239D5B9A239D@SHSMSX104.ccr.corp.intel.com> <0C09AFA07DD0434D9E2A0C6AEB0483103B8ED350@shsmsx102.ccr.corp.intel.com> <734D49CCEBEEF84792F5B80ED585239D5B9A458B@SHSMSX104.ccr.corp.intel.com> In-Reply-To: <734D49CCEBEEF84792F5B80ED585239D5B9A458B@SHSMSX104.ccr.corp.intel.com> Accept-Language: zh-CN, en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.239.127.40] MIME-Version: 1.0 Subject: Re: [PATCH V2 3/3] DuetPkg FsVariable: Update GetNextVariableName to follow UEFI 2.7 X-BeenThere: edk2-devel@lists.01.org X-Mailman-Version: 2.1.22 Precedence: list List-Id: EDK II Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 26 Jun 2017 05:39:55 -0000 Content-Language: en-US Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable It is to return EFI_INVALID_PARAMETER when the input VariableName and Vendo= rGuid are not a valid variable to search next variable. It is added from UEFI 2.7 spec. Before the spec change, the code is to return EFI_NOT_FOUND at that case. After the spec change, EFI_NOT_FOUND seemingly is reserved to indicate the = ending of searching. Thanks, Star -----Original Message----- From: Ni, Ruiyu=20 Sent: Monday, June 26, 2017 1:37 PM To: Zeng, Star ; edk2-devel@lists.01.org Cc: Gao, Liming Subject: RE: [PATCH V2 3/3] DuetPkg FsVariable: Update GetNextVariableName = to follow UEFI 2.7 I understand your point. But I do think it hurts readability. BTW, what does the below change does? if (Variable.CurrPtr =3D=3D NULL || EFI_ERROR (Status)) { + if (VariableName[0] !=3D 0) { + // + // The input values of VariableName and VendorGuid are not a name an= d GUID of an existing variable. + // + Status =3D EFI_INVALID_PARAMETER; + } return Status; } Thanks/Ray > -----Original Message----- > From: Zeng, Star > Sent: Monday, June 26, 2017 11:05 AM > To: Ni, Ruiyu ; edk2-devel@lists.01.org > Cc: Gao, Liming ; Zeng, Star=20 > > Subject: RE: [PATCH V2 3/3] DuetPkg FsVariable: Update=20 > GetNextVariableName to follow UEFI 2.7 >=20 > Ray, >=20 > The code is like low hanging fruit from my practice for me, and I=20 > don't think it hurts readability although it may not bring performance=20 > improvement, it depends on how many variables in variable region, how=20 > many times of calling GetNextVariableName, and how fast of GetNextVariabl= eName. >=20 > The code practice I did is on NT32 and my real platforms. Is there=20 > anyone can make sure he/she tested all the systems in the world for their= code? >=20 >=20 > Anyway, I can update the patch if you insist. >=20 >=20 > Thanks, > Star > -----Original Message----- > From: Ni, Ruiyu > Sent: Saturday, June 24, 2017 10:08 AM > To: Zeng, Star ; edk2-devel@lists.01.org > Cc: Gao, Liming > Subject: RE: [PATCH V2 3/3] DuetPkg FsVariable: Update=20 > GetNextVariableName to follow UEFI 2.7 >=20 > Star, > I don't recommend to add the additional check for performance=20 > consideration. > Because we have no idea what the input VariableName buffer is like. > If the VariableName is like ['\0', '?', '?', '?'] with MaxLen equals=20 > to 4, "VariableName[MaxLen-1] !=3D 0" check is redundant. > The NT32 case you met cannot represent the all possible cases. > You could use the possibility theory to decide what the most efficient wa= y is. >=20 > Additionally I think code readability is more important than efficiency. > In this case, we need the data about the performance improvement to=20 > decide whether this check is necessary. >=20 >=20 > Regards, > Ray >=20 > >-----Original Message----- > >From: Zeng, Star > >Sent: Friday, June 23, 2017 5:33 PM > >To: Ni, Ruiyu ; edk2-devel@lists.01.org > >Cc: Gao, Liming ; Zeng, Star=20 > > > >Subject: RE: [PATCH V2 3/3] DuetPkg FsVariable: Update=20 > >GetNextVariableName to follow UEFI 2.7 > > > >Ray, > > > >It is to pass the check quickly and avoid scanning all the chars in=20 > >VariableName by StrnLenS for normal boot without invalid cases. > >I did experiments in the code of GetNextVariableName with below debug=20 > >code for normal boot on NT32 and my real platforms, all the cases=20 > >will go > into the branch "xxx 2". > > if (((VariableName[MaxLen - 1] !=3D 0))) { > > DEBUG ((DEBUG_INFO, "xxx 1\n")); > > } else { > > DEBUG ((DEBUG_INFO, "xxx 2\n")); > > } > > > > > >Thanks, > >Star > >-----Original Message----- > >From: Ni, Ruiyu > >Sent: Friday, June 23, 2017 4:20 PM > >To: Zeng, Star ; edk2-devel@lists.01.org > >Cc: Gao, Liming > >Subject: RE: [PATCH V2 3/3] DuetPkg FsVariable: Update=20 > >GetNextVariableName to follow UEFI 2.7 > > > >Star, > >What's the benefit of this check "VariableName[MaxLen - 1] !=3D 0"? > >I think this check "StrnLenS (VariableName, MaxLen) =3D=3D MaxLen" shoul= d=20 > >be > enough. > > > >Thanks/Ray > > > >> -----Original Message----- > >> From: Zeng, Star > >> Sent: Friday, June 23, 2017 4:08 PM > >> To: edk2-devel@lists.01.org > >> Cc: Zeng, Star ; Gao, Liming=20 > >> ; Ni, Ruiyu > >> Subject: [PATCH V2 3/3] DuetPkg FsVariable: Update=20 > >> GetNextVariableName to follow UEFI 2.7 > >> > >> "The size must be large enough to fit input string supplied in=20 > >> VariableName buffer" is added in the description for VariableNameSize. > >> And two cases of EFI_INVALID_PARAMETER are added. > >> 1. The input values of VariableName and VendorGuid are not a name and > >> GUID of an existing variable. > >> 2. Null-terminator is not found in the first VariableNameSize bytes of > >> the input VariableName buffer. > >> > >> This patch is to update code to follow them. > >> > >> Cc: Liming Gao > >> Cc: Ruiyu Ni > >> Contributed-under: TianoCore Contribution Agreement 1.0 > >> Signed-off-by: Star Zeng > >> --- > >> DuetPkg/FSVariable/FSVariable.c | 21 ++++++++++++++++++++- > >> 1 file changed, 20 insertions(+), 1 deletion(-) > >> > >> diff --git a/DuetPkg/FSVariable/FSVariable.c=20 > >> b/DuetPkg/FSVariable/FSVariable.c index 34b79305c871..6069cfa8fb98 > >> 100644 > >> --- a/DuetPkg/FSVariable/FSVariable.c > >> +++ b/DuetPkg/FSVariable/FSVariable.c > >> @@ -6,7 +6,7 @@ disk. They can be changed by user. BIOS is not able=20 > >> to protoect those. > >> Duet trusts all meta data from disk. If variable code, variable=20 > >> metadata and variable data is modified in inproper way, the=20 > >> behavior is undefined. > >> > >> -Copyright (c) 2006 - 2016, Intel Corporation. All rights=20 > >> reserved.
> >> +Copyright (c) 2006 - 2017, Intel Corporation. All rights=20 > >> +reserved.
> >> This program and the accompanying materials are licensed and made=20 > >> available under the terms and conditions of the BSD License which=20 > >> accompanies this distribution. The full text of the license may be=20 > >> found at @@ -1400,14 +1400,33 @@ Returns: > >> VARIABLE_POINTER_TRACK Variable; > >> UINTN VarNameSize; > >> EFI_STATUS Status; > >> + UINTN MaxLen; > >> > >> if (VariableNameSize =3D=3D NULL || VariableName =3D=3D NULL ||=20 > >> VendorGuid =3D=3D > >> NULL) { > >> return EFI_INVALID_PARAMETER; > >> } > >> > >> + // > >> + // Calculate the possible maximum length of name string,=20 > >> + including the Null > >> terminator. > >> + // > >> + MaxLen =3D *VariableNameSize / sizeof (CHAR16); if ((MaxLen =3D=3D= 0) > >> + || > >> + ((VariableName[MaxLen - 1] !=3D 0) && (StrnLenS (VariableName, > >> + MaxLen) > >> =3D=3D MaxLen))) { > >> + // > >> + // Null-terminator is not found in the first VariableNameSize=20 > >> + bytes of the > >> input VariableName buffer. > >> + // > >> + return EFI_INVALID_PARAMETER; > >> + } > >> + > >> Status =3D FindVariable (VariableName, VendorGuid, &Variable); > >> > >> if (Variable.CurrPtr =3D=3D NULL || EFI_ERROR (Status)) { > >> + if (VariableName[0] !=3D 0) { > >> + // > >> + // The input values of VariableName and VendorGuid are not a=20 > >> + name > >> and GUID of an existing variable. > >> + // > >> + Status =3D EFI_INVALID_PARAMETER; > >> + } > >> return Status; > >> } > >> > >> -- > >> 2.7.0.windows.1