From 19ab8f850f2937915598958b7c54957eed1a94c5 Mon Sep 17 00:00:00 2001 From: Simon Atanasyan Date: Fri, 16 May 2014 16:01:00 +0000 Subject: [PATCH] [yaml2obj][ELF] Add an optional `Size` field to the YAML section declaration. Now the only method to configure ELF section's content and size is to assign a hexadecimal string to the `Content` field. Unfortunately this way is completely useless when you need to declare a really large section. To solve this problem this patch adds one more optional field `Size` to the `RawContentSection` structure. When yaml2obj generates an ELF file it uses the following algorithm: 1. If both `Content` and `Size` fields are missed create an empty section. 2. If only `Content` field is missed take section length from the `Size` field and fill the section by zero. 3. If only `Size` field is missed create a section using data from the `Content` field. 4. If both `Content` and `Size` fields are provided validate that the `Size` value is not less than size of `Content` data. Than take section length from the `Size`, fill beginning of the section by `Content` and the rest by zero. Examples -------- * Create a section 0x10000 bytes long filled by zero Name: .data Type: SHT_PROGBITS Flags: [ SHF_ALLOC ] Size: 0x10000 * Create a section 0x10000 bytes long starting from 'CA' 'FE' 'BA' 'BE' Name: .data Type: SHT_PROGBITS Flags: [ SHF_ALLOC ] Content: CAFEBABE Size: 0x10000 The patch reviewed by Michael Spencer. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208995 91177308-0d34-0410-b5e6-96231b3b80d8 --- include/llvm/Object/ELFYAML.h | 2 ++ lib/Object/ELFYAML.cpp | 9 +++++++ test/Object/yaml2obj-elf-section-basic.yaml | 25 ++++++++++++++++++ .../yaml2obj-elf-section-invalid-size.yaml | 26 +++++++++++++++++++ tools/obj2yaml/elf2yaml.cpp | 1 + tools/yaml2obj/yaml2elf.cpp | 9 +++++-- 6 files changed, 70 insertions(+), 2 deletions(-) create mode 100644 test/Object/yaml2obj-elf-section-invalid-size.yaml diff --git a/include/llvm/Object/ELFYAML.h b/include/llvm/Object/ELFYAML.h index 5be7534557e..524e55b07e1 100644 --- a/include/llvm/Object/ELFYAML.h +++ b/include/llvm/Object/ELFYAML.h @@ -83,6 +83,7 @@ struct Section { }; struct RawContentSection : Section { object::yaml::BinaryRef Content; + llvm::yaml::Hex64 Size; RawContentSection() : Section(SectionKind::RawContent) {} static bool classof(const Section *S) { return S->Kind == SectionKind::RawContent; @@ -193,6 +194,7 @@ template <> struct MappingTraits { template <> struct MappingTraits> { static void mapping(IO &IO, std::unique_ptr &Section); + static StringRef validate(IO &io, std::unique_ptr &Section); }; template <> diff --git a/lib/Object/ELFYAML.cpp b/lib/Object/ELFYAML.cpp index c396f66ee65..547720ddc32 100644 --- a/lib/Object/ELFYAML.cpp +++ b/lib/Object/ELFYAML.cpp @@ -658,6 +658,7 @@ static void commonSectionMapping(IO &IO, ELFYAML::Section &Section) { static void sectionMapping(IO &IO, ELFYAML::RawContentSection &Section) { commonSectionMapping(IO, Section); IO.mapOptional("Content", Section.Content); + IO.mapOptional("Size", Section.Size, Hex64(Section.Content.binary_size())); } static void sectionMapping(IO &IO, ELFYAML::RelocationSection &Section) { @@ -687,6 +688,14 @@ void MappingTraits>::mapping( } } +StringRef MappingTraits>::validate( + IO &io, std::unique_ptr &Section) { + const auto *RawSection = dyn_cast(Section.get()); + if (!RawSection || RawSection->Size >= RawSection->Content.binary_size()) + return StringRef(); + return "Section size must be greater or equal to the content size"; +} + void MappingTraits::mapping(IO &IO, ELFYAML::Relocation &Rel) { IO.mapRequired("Offset", Rel.Offset); diff --git a/test/Object/yaml2obj-elf-section-basic.yaml b/test/Object/yaml2obj-elf-section-basic.yaml index 7316b7f5bc7..56a3fd6e5f1 100644 --- a/test/Object/yaml2obj-elf-section-basic.yaml +++ b/test/Object/yaml2obj-elf-section-basic.yaml @@ -17,6 +17,14 @@ Sections: Content: EBFE AddressAlign: 2 + - Name: .data + Type: SHT_PROGBITS + Flags: [ SHF_ALLOC ] + Address: 0xCAFECAFE + Content: FEBF + Size: 8 + AddressAlign: 2 + # CHECK: Section { # CHECK: Index: 0 # CHECK: Type: SHT_NULL (0x0) @@ -38,6 +46,23 @@ Sections: # CHECK-NEXT: ) # # CHECK: Section { +# CHECK: Name: .data +# CHECK-NEXT: Type: SHT_PROGBITS (0x1) +# CHECK-NEXT: Flags [ (0x2) +# CHECK-NEXT: SHF_ALLOC (0x2) +# CHECK-NEXT: ] +# CHECK-NEXT: Address: 0xCAFECAFE +# CHECK-NEXT: Offset: 0x1D0 +# CHECK-NEXT: Size: 8 +# CHECK-NEXT: Link: 0 +# CHECK-NEXT: Info: 0 +# CHECK-NEXT: AddressAlignment: 2 +# CHECK-NEXT: EntrySize: 0 +# CHECK-NEXT: SectionData ( +# CHECK-NEXT: 0000: FEBF0000 00000000 |........| +# CHECK-NEXT: ) +# +# CHECK: Section { # CHECK: Name: .symtab (25) # CHECK: Type: SHT_SYMTAB (0x2) # CHECK: } diff --git a/test/Object/yaml2obj-elf-section-invalid-size.yaml b/test/Object/yaml2obj-elf-section-invalid-size.yaml new file mode 100644 index 00000000000..d0cb370072d --- /dev/null +++ b/test/Object/yaml2obj-elf-section-invalid-size.yaml @@ -0,0 +1,26 @@ +# RUN: not yaml2obj -format=elf -o %t %s 2>&1 | FileCheck %s + +!ELF +FileHeader: + Class: ELFCLASS64 + Data: ELFDATA2LSB + Type: ET_REL + Machine: EM_X86_64 + +Sections: + - Name: .text + Type: SHT_PROGBITS + Flags: [ SHF_ALLOC, SHF_EXECINSTR ] + Content: EBFE + AddressAlign: 2 + + - Name: .data + Type: SHT_PROGBITS + Flags: [ SHF_ALLOC ] + Content: 0000000000000000 + Size: 2 + +# CHECK: YAML:17:5: error: Section size must be greater or equal to the content size +# CHECK-NEXT: - Name: .data +# CHECK-NEXT: ^ +# CHECK-NEXT: yaml2obj: Failed to parse YAML file! diff --git a/tools/obj2yaml/elf2yaml.cpp b/tools/obj2yaml/elf2yaml.cpp index 38afa138d97..7642921b485 100644 --- a/tools/obj2yaml/elf2yaml.cpp +++ b/tools/obj2yaml/elf2yaml.cpp @@ -254,6 +254,7 @@ ELFDumper::dumpContentSection(const Elf_Shdr *Shdr) { if (error_code EC = ContentOrErr.getError()) return EC; S->Content = object::yaml::BinaryRef(ContentOrErr.get()); + S->Size = S->Content.binary_size(); return S.release(); } diff --git a/tools/yaml2obj/yaml2elf.cpp b/tools/yaml2obj/yaml2elf.cpp index 3190b27d324..bb52cda7c1e 100644 --- a/tools/yaml2obj/yaml2elf.cpp +++ b/tools/yaml2obj/yaml2elf.cpp @@ -314,9 +314,14 @@ void ELFState::writeSectionContent(Elf_Shdr &SHeader, const ELFYAML::RawContentSection &Section, ContiguousBlobAccumulator &CBA) { - Section.Content.writeAsBinary(CBA.getOSAndAlignedOffset(SHeader.sh_offset)); + assert(Section.Size >= Section.Content.binary_size() && + "Section size and section content are inconsistent"); + raw_ostream &OS = CBA.getOSAndAlignedOffset(SHeader.sh_offset); + Section.Content.writeAsBinary(OS); + for (auto i = Section.Content.binary_size(); i < Section.Size; ++i) + OS.write(0); SHeader.sh_entsize = 0; - SHeader.sh_size = Section.Content.binary_size(); + SHeader.sh_size = Section.Size; } template -- 2.34.1