[llvm] r313767 - Reland "[llvm-objcopy] Add support for .dynamic, .dynsym, and .dynstr"
Jake Ehrlich via llvm-commits
llvm-commits at lists.llvm.org
Wed Sep 20 10:11:58 PDT 2017
Author: jakehehrlich
Date: Wed Sep 20 10:11:58 2017
New Revision: 313767
URL: http://llvm.org/viewvc/llvm-project?rev=313767&view=rev
Log:
Reland "[llvm-objcopy] Add support for .dynamic, .dynsym, and .dynstr"
I overzealously landed this before I was sure that another change
wouldn't break the build that this change depends on.
This change adds support for sections involved in dynamic loading such
as SHT_DYNAMIC, SHT_DYNSYM, and allocated string tables.
The two added binaries used for tests can be downloaded here and here
Differential Revision: https://reviews.llvm.org/D36560
Added:
llvm/trunk/test/tools/llvm-objcopy/dynamic.test
llvm/trunk/test/tools/llvm-objcopy/dynstr.test
llvm/trunk/test/tools/llvm-objcopy/dynsym.test
Modified:
llvm/trunk/tools/llvm-objcopy/Object.cpp
llvm/trunk/tools/llvm-objcopy/Object.h
Added: llvm/trunk/test/tools/llvm-objcopy/dynamic.test
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/tools/llvm-objcopy/dynamic.test?rev=313767&view=auto
==============================================================================
--- llvm/trunk/test/tools/llvm-objcopy/dynamic.test (added)
+++ llvm/trunk/test/tools/llvm-objcopy/dynamic.test Wed Sep 20 10:11:58 2017
@@ -0,0 +1,27 @@
+# RUN: llvm-objcopy %p/Inputs/dynamic.so %t
+# RUN: llvm-readobj -dynamic-table %t | FileCheck %s
+# RUN: llvm-readobj -sections %t | FileCheck -check-prefix=LINK %s
+
+#CHECK: DynamicSection [
+#CHECK-NEXT: Tag Type Name/Value
+#CHECK-NEXT: 0x0000000000000006 SYMTAB 0x1C8
+#CHECK-NEXT: 0x000000000000000B SYMENT 24
+#CHECK-NEXT: 0x0000000000000005 STRTAB 0x210
+#CHECK-NEXT: 0x000000000000000A STRSZ 5
+#CHECK-NEXT: 0x0000000000000004 HASH 0x1F8
+#CHECK-NEXT: 0x0000000000000000 NULL 0x0
+#CHECK-NEXT:]
+
+#LINK: Index: 3
+#LINK-NEXT: Name: .dynstr
+
+#LINK: Name: .dynamic
+#LINK-NEXT: Type: SHT_DYNAMIC
+#LINK-NEXT: Flags [
+#LINK-NEXT: SHF_ALLOC
+#LINK-NEXT: SHF_WRITE
+#LINK-NEXT: ]
+#LINK-NEXT: Address:
+#LINK-NEXT: Offset:
+#LINK-NEXT: Size:
+#LINK-NEXT: Link: 3
Added: llvm/trunk/test/tools/llvm-objcopy/dynstr.test
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/tools/llvm-objcopy/dynstr.test?rev=313767&view=auto
==============================================================================
--- llvm/trunk/test/tools/llvm-objcopy/dynstr.test (added)
+++ llvm/trunk/test/tools/llvm-objcopy/dynstr.test Wed Sep 20 10:11:58 2017
@@ -0,0 +1,32 @@
+# RUN: yaml2obj %s > %t
+# RUN: llvm-objcopy %t %t2
+# RUN: llvm-readobj -sections -section-data %t2 | FileCheck %s
+
+!ELF
+FileHeader:
+ Class: ELFCLASS64
+ Data: ELFDATA2LSB
+ Type: ET_EXEC
+ Machine: EM_X86_64
+Sections:
+ - Name: .dynstr
+ Type: SHT_STRTAB
+ Flags: [ SHF_ALLOC ]
+ Address: 0x1000
+ Content: "002EDEADBEEF002EBAADF00D00"
+
+#CHECK: Name: .dynstr
+#CHECK-NEXT: Type: SHT_STRTAB
+#CHECK-NEXT: Flags [
+#CHECK-NEXT: SHF_ALLOC
+#CHECK-NEXT: ]
+#CHECK-NEXT: Address: 0x1000
+#CHECK-NEXT: Offset:
+#CHECK-NEXT: Size: 13
+#CHECK-NEXT: Link:
+#CHECK-NEXT: Info:
+#CHECK-NEXT: AddressAlignment:
+#CHECK-NEXT: EntrySize:
+#CHECK-NEXT: SectionData (
+#CHECK-NEXT: 0000: 002EDEAD BEEF002E BAADF00D 00
+#CHECK-NEXT: )
Added: llvm/trunk/test/tools/llvm-objcopy/dynsym.test
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/tools/llvm-objcopy/dynsym.test?rev=313767&view=auto
==============================================================================
--- llvm/trunk/test/tools/llvm-objcopy/dynsym.test (added)
+++ llvm/trunk/test/tools/llvm-objcopy/dynsym.test Wed Sep 20 10:11:58 2017
@@ -0,0 +1,64 @@
+# RUN: llvm-objcopy %p/Inputs/dynsym.so %t
+# RUN: llvm-readobj -dyn-symbols %t | FileCheck %s
+# RUN: llvm-readobj -sections %t | FileCheck -check-prefix=LINK %s
+
+#LINK: Name: .dynsym
+#LINK-NEXT: Type: SHT_DYNSYM
+#LINK-NEXT: Flags [
+#LINK-NEXT: SHF_ALLOC
+#LINK-NEXT: ]
+#LINK-NEXT: Address:
+#LINK-NEXT: Offset:
+#LINK-NEXT: Size:
+#LINK-NEXT: Link: 3
+
+#LINK: Index: 3
+#LINK-NEXT: Name: .dynstr
+
+#CHECK: DynamicSymbols [
+#CHECK-NEXT: Symbol {
+#CHECK-NEXT: Name: @ (0)
+#CHECK-NEXT: Value: 0x0
+#CHECK-NEXT: Size: 0
+#CHECK-NEXT: Binding: Local
+#CHECK-NEXT: Type: None (0x0)
+#CHECK-NEXT: Other: 0
+#CHECK-NEXT: Section: Undefined (0x0)
+#CHECK-NEXT: }
+#CHECK-NEXT: Symbol {
+#CHECK-NEXT: Name: bang@ (1)
+#CHECK-NEXT: Value: 0x4000
+#CHECK-NEXT: Size: 8
+#CHECK-NEXT: Binding: Global (0x1)
+#CHECK-NEXT: Type: Object (0x1)
+#CHECK-NEXT: Other: 0
+#CHECK-NEXT: Section: .bss (0x7)
+#CHECK-NEXT: }
+#CHECK-NEXT: Symbol {
+#CHECK-NEXT: Name: bar@ (6)
+#CHECK-NEXT: Value: 0x1001
+#CHECK-NEXT: Size: 0
+#CHECK-NEXT: Binding: Global (0x1)
+#CHECK-NEXT: Type: Function (0x2)
+#CHECK-NEXT: Other: 0
+#CHECK-NEXT: Section: .text (0x4)
+#CHECK-NEXT: }
+#CHECK-NEXT: Symbol {
+#CHECK-NEXT: Name: baz@ (10)
+#CHECK-NEXT: Value: 0x2000
+#CHECK-NEXT: Size: 0
+#CHECK-NEXT: Binding: Global (0x1)
+#CHECK-NEXT: Type: Object (0x1)
+#CHECK-NEXT: Other: 0
+#CHECK-NEXT: Section: .data (0x5)
+#CHECK-NEXT: }
+#CHECK-NEXT: Symbol {
+#CHECK-NEXT: Name: foo@ (14)
+#CHECK-NEXT: Value: 0x1000
+#CHECK-NEXT: Size: 0
+#CHECK-NEXT: Binding: Global (0x1)
+#CHECK-NEXT: Type: Function (0x2)
+#CHECK-NEXT: Other: 0
+#CHECK-NEXT: Section: .text (0x4)
+#CHECK-NEXT: }
+#CHECK-NEXT:]
Modified: llvm/trunk/tools/llvm-objcopy/Object.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/tools/llvm-objcopy/Object.cpp?rev=313767&r1=313766&r2=313767&view=diff
==============================================================================
--- llvm/trunk/tools/llvm-objcopy/Object.cpp (original)
+++ llvm/trunk/tools/llvm-objcopy/Object.cpp Wed Sep 20 10:11:58 2017
@@ -228,6 +228,12 @@ void RelocationSection<ELFT>::writeSecti
writeRel(reinterpret_cast<Elf_Rela *>(Buf));
}
+bool SectionWithStrTab::classof(const SectionBase *S) {
+ return isa<DynamicSymbolTableSection>(S) || isa<DynamicSection>(S);
+}
+
+void SectionWithStrTab::finalize() { this->Link = StrTab->Index; }
+
// Returns true IFF a section is wholly inside the range of a segment
static bool sectionWithinSegment(const SectionBase &Section,
const Segment &Segment) {
@@ -308,16 +314,12 @@ void Object<ELFT>::initSymbolTable(const
SymbolTableSection *SymTab) {
SymTab->Size = 0;
- if (SymbolTable->Link - 1 >= Sections.size())
- error("Symbol table has link index of " + Twine(SymbolTable->Link) +
- " which is not a valid index");
-
- if (auto StrTab =
- dyn_cast<StringTableSection>(Sections[SymbolTable->Link - 1].get()))
- SymTab->setStrTab(StrTab);
- else
- error("Symbol table has link index of " + Twine(SymbolTable->Link) +
- "which is not a string table");
+ SymTab->setStrTab(getSectionOfType<StringTableSection>(
+ SymbolTable->Link,
+ "Symbol table has link index of " + Twine(SymTab->Link) +
+ " which is not a valid index",
+ "Symbol table has link index of " + Twine(SymTab->Link) +
+ " which is not a string table"));
const Elf_Shdr &Shdr = *unwrapOrError(ElfFile.getSection(SymTab->Index));
StringRef StrTabData = unwrapOrError(ElfFile.getStringTableForSymtab(Shdr));
@@ -325,6 +327,7 @@ void Object<ELFT>::initSymbolTable(const
for (const auto &Sym : unwrapOrError(ElfFile.symbols(&Shdr))) {
SectionBase *DefSection = nullptr;
StringRef Name = unwrapOrError(Sym.getName(StrTabData));
+
if (Sym.st_shndx >= SHN_LORESERVE) {
if (!isValidReservedSectionIndex(Sym.st_shndx, Machine)) {
error(
@@ -333,12 +336,12 @@ void Object<ELFT>::initSymbolTable(const
Twine(Sym.st_shndx));
}
} else if (Sym.st_shndx != SHN_UNDEF) {
- if (Sym.st_shndx >= Sections.size())
- error("Symbol '" + Name +
- "' is defined in invalid section with index " +
+ DefSection = getSection(
+ Sym.st_shndx,
+ "Symbol '" + Name + "' is defined in invalid section with index " +
Twine(Sym.st_shndx));
- DefSection = Sections[Sym.st_shndx - 1].get();
}
+
SymTab->addSymbol(Name, Sym.getBinding(), Sym.getType(), DefSection,
Sym.getValue(), Sym.st_shndx, Sym.st_size);
}
@@ -366,6 +369,22 @@ void initRelocations(RelocationSection<E
}
template <class ELFT>
+SectionBase *Object<ELFT>::getSection(uint16_t Index, Twine ErrMsg) {
+ if (Index == SHN_UNDEF || Index > Sections.size())
+ error(ErrMsg);
+ return Sections[Index - 1].get();
+}
+
+template <class ELFT>
+template <class T>
+T *Object<ELFT>::getSectionOfType(uint16_t Index, Twine IndexErrMsg,
+ Twine TypeErrMsg) {
+ if (T *TSec = llvm::dyn_cast<T>(getSection(Index, IndexErrMsg)))
+ return TSec;
+ error(TypeErrMsg);
+}
+
+template <class ELFT>
std::unique_ptr<SectionBase>
Object<ELFT>::makeSection(const llvm::object::ELFFile<ELFT> &ElfFile,
const Elf_Shdr &Shdr) {
@@ -375,7 +394,26 @@ Object<ELFT>::makeSection(const llvm::ob
case SHT_RELA:
return llvm::make_unique<RelocationSection<ELFT>>();
case SHT_STRTAB:
+ // If a string table is allocated we don't want to mess with it. That would
+ // mean altering the memory image. There are no special link types or
+ // anything so we can just use a Section.
+ if (Shdr.sh_flags & SHF_ALLOC) {
+ Data = unwrapOrError(ElfFile.getSectionContents(&Shdr));
+ return llvm::make_unique<Section>(Data);
+ }
return llvm::make_unique<StringTableSection>();
+ case SHT_HASH:
+ case SHT_GNU_HASH:
+ // Hash tables should refer to SHT_DYNSYM which we're not going to change.
+ // Because of this we don't need to mess with the hash tables either.
+ Data = unwrapOrError(ElfFile.getSectionContents(&Shdr));
+ return llvm::make_unique<Section>(Data);
+ case SHT_DYNSYM:
+ Data = unwrapOrError(ElfFile.getSectionContents(&Shdr));
+ return llvm::make_unique<DynamicSymbolTableSection>(Data);
+ case SHT_DYNAMIC:
+ Data = unwrapOrError(ElfFile.getSectionContents(&Shdr));
+ return llvm::make_unique<DynamicSection>(Data);
case SHT_SYMTAB: {
auto SymTab = llvm::make_unique<SymbolTableSectionImpl<ELFT>>();
SymbolTable = SymTab.get();
@@ -423,28 +461,35 @@ void Object<ELFT>::readSectionHeaders(co
// relocation sections.
for (auto &Section : Sections) {
if (auto RelSec = dyn_cast<RelocationSection<ELFT>>(Section.get())) {
- if (RelSec->Link - 1 >= Sections.size() || RelSec->Link == 0) {
- error("Link field value " + Twine(RelSec->Link) + " in section " +
- RelSec->Name + " is invalid");
- }
- if (RelSec->Info - 1 >= Sections.size() || RelSec->Info == 0) {
- error("Info field value " + Twine(RelSec->Link) + " in section " +
- RelSec->Name + " is invalid");
- }
- auto SymTab =
- dyn_cast<SymbolTableSection>(Sections[RelSec->Link - 1].get());
- if (SymTab == nullptr) {
- error("Link field of relocation section " + RelSec->Name +
- " is not a symbol table");
- }
+
+ auto SymTab = getSectionOfType<SymbolTableSection>(
+ RelSec->Link,
+ "Link field value " + Twine(RelSec->Link) + " in section " +
+ RelSec->Name + " is invalid",
+ "Link field value " + Twine(RelSec->Link) + " in section " +
+ RelSec->Name + " is not a symbol table");
RelSec->setSymTab(SymTab);
- RelSec->setSection(Sections[RelSec->Info - 1].get());
+
+ RelSec->setSection(getSection(RelSec->Info,
+ "Info field value " + Twine(RelSec->Link) +
+ " in section " + RelSec->Name +
+ " is invalid"));
+
auto Shdr = unwrapOrError(ElfFile.sections()).begin() + RelSec->Index;
if (RelSec->Type == SHT_REL)
initRelocations(RelSec, SymTab, unwrapOrError(ElfFile.rels(Shdr)));
else
initRelocations(RelSec, SymTab, unwrapOrError(ElfFile.relas(Shdr)));
}
+
+ if (auto Sec = dyn_cast<SectionWithStrTab>(Section.get())) {
+ Sec->setStrTab(getSectionOfType<StringTableSection>(
+ Sec->Link,
+ "Link field value " + Twine(Sec->Link) + " in section " + Sec->Name +
+ " is invalid",
+ "Link field value " + Twine(Sec->Link) + " in section " + Sec->Name +
+ " is not a string table"));
+ }
}
}
@@ -462,8 +507,12 @@ template <class ELFT> Object<ELFT>::Obje
readSectionHeaders(ElfFile);
readProgramHeaders(ElfFile);
- SectionNames =
- dyn_cast<StringTableSection>(Sections[Ehdr.e_shstrndx - 1].get());
+ SectionNames = getSectionOfType<StringTableSection>(
+ Ehdr.e_shstrndx,
+ "e_shstrndx field value " + Twine(Ehdr.e_shstrndx) + " in elf header " +
+ " is invalid",
+ "e_shstrndx field value " + Twine(Ehdr.e_shstrndx) + " in elf header " +
+ " is not a string table");
}
template <class ELFT>
Modified: llvm/trunk/tools/llvm-objcopy/Object.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/tools/llvm-objcopy/Object.h?rev=313767&r1=313766&r2=313767&view=diff
==============================================================================
--- llvm/trunk/tools/llvm-objcopy/Object.h (original)
+++ llvm/trunk/tools/llvm-objcopy/Object.h Wed Sep 20 10:11:58 2017
@@ -194,6 +194,34 @@ public:
}
};
+class SectionWithStrTab : public Section {
+private:
+ StringTableSection *StrTab;
+
+public:
+ SectionWithStrTab(llvm::ArrayRef<uint8_t> Data) : Section(Data) {}
+ void setStrTab(StringTableSection *StringTable) { StrTab = StringTable; }
+ void finalize() override;
+ static bool classof(const SectionBase *S);
+};
+
+class DynamicSymbolTableSection : public SectionWithStrTab {
+public:
+ DynamicSymbolTableSection(llvm::ArrayRef<uint8_t> Data)
+ : SectionWithStrTab(Data) {}
+ static bool classof(const SectionBase *S) {
+ return S->Type == llvm::ELF::SHT_DYNSYM;
+ }
+};
+
+class DynamicSection : public SectionWithStrTab {
+public:
+ DynamicSection(llvm::ArrayRef<uint8_t> Data) : SectionWithStrTab(Data) {}
+ static bool classof(const SectionBase *S) {
+ return S->Type == llvm::ELF::SHT_DYNAMIC;
+ }
+};
+
template <class ELFT> class Object {
private:
typedef std::unique_ptr<SectionBase> SecPtr;
@@ -210,6 +238,12 @@ private:
void readProgramHeaders(const llvm::object::ELFFile<ELFT> &ElfFile);
void readSectionHeaders(const llvm::object::ELFFile<ELFT> &ElfFile);
+ SectionBase *getSection(uint16_t Index, llvm::Twine ErrMsg);
+
+ template <class T>
+ T *getSectionOfType(uint16_t Index, llvm::Twine IndexErrMsg,
+ llvm::Twine TypeErrMsg);
+
protected:
StringTableSection *SectionNames;
SymbolTableSection *SymbolTable;
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