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pjs/build/unix/elfhack/elfxx.h

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/* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is elfhack.
*
* The Initial Developer of the Original Code is
* Mozilla Foundation.
* Portions created by the Initial Developer are Copyright (C) 2010
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Mike Hommey <mh@glandium.org>
*
* Alternatively, the contents of this file may be used under the terms of
* either the GNU General Public License Version 2 or later (the "GPL"), or
* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
#include <stdexcept>
#include <list>
#include <vector>
#include <cstring>
#include <iostream>
#include <fstream>
#include <algorithm>
#include <elf.h>
#include <asm/byteorder.h>
// Technically, __*_to_cpu and __cpu_to* function are equivalent,
// so swap can use either of both.
#define def_swap(endian, type, bits) \
static inline type ## bits ## _t swap(type ## bits ## _t i) { \
return __ ## endian ## bits ## _to_cpu(i); \
}
class little_endian {
public:
def_swap(le, uint, 16);
def_swap(le, uint, 32);
def_swap(le, uint, 64);
def_swap(le, int, 16);
def_swap(le, int, 32);
def_swap(le, int, 64);
};
class big_endian {
public:
def_swap(be, uint, 16);
def_swap(be, uint, 32);
def_swap(be, uint, 64);
def_swap(be, int, 16);
def_swap(be, int, 32);
def_swap(be, int, 64);
};
// forward declaration
class ElfSection;
class ElfSegment;
// TODO: Rename Elf_* types
class Elf_Ehdr;
class Elf_Phdr;
class Elf;
class ElfDynamic_Section;
class ElfStrtab_Section;
class Elf_Ehdr_Traits {
public:
typedef Elf32_Ehdr Type32;
typedef Elf64_Ehdr Type64;
template <class endian, typename R, typename T>
static void swap(T &t, R &r);
};
class Elf_Phdr_Traits {
public:
typedef Elf32_Phdr Type32;
typedef Elf64_Phdr Type64;
template <class endian, typename R, typename T>
static void swap(T &t, R &r);
};
class Elf_Shdr_Traits {
public:
typedef Elf32_Shdr Type32;
typedef Elf64_Shdr Type64;
template <class endian, typename R, typename T>
static void swap(T &t, R &r);
};
class Elf_Dyn_Traits {
public:
typedef Elf32_Dyn Type32;
typedef Elf64_Dyn Type64;
template <class endian, typename R, typename T>
static void swap(T &t, R &r);
};
class Elf_Sym_Traits {
public:
typedef Elf32_Sym Type32;
typedef Elf64_Sym Type64;
template <class endian, typename R, typename T>
static void swap(T &t, R &r);
};
class Elf_Rel_Traits {
public:
typedef Elf32_Rel Type32;
typedef Elf64_Rel Type64;
template <class endian, typename R, typename T>
static void swap(T &t, R &r);
};
class Elf_Rela_Traits {
public:
typedef Elf32_Rela Type32;
typedef Elf64_Rela Type64;
template <class endian, typename R, typename T>
static void swap(T &t, R &r);
};
class ElfValue {
public:
virtual unsigned int getValue() { return 0; }
virtual ElfSection *getSection() { return NULL; }
};
class ElfPlainValue: public ElfValue {
unsigned int value;
public:
ElfPlainValue(unsigned int val): value(val) {};
unsigned int getValue() { return value; }
};
class ElfLocation: public ElfValue {
ElfSection *section;
unsigned int offset;
public:
enum position { ABSOLUTE, RELATIVE };
ElfLocation(): section(NULL), offset(0) {};
ElfLocation(ElfSection *section, unsigned int off, enum position pos = RELATIVE);
ElfLocation(unsigned int location, Elf *elf);
unsigned int getValue();
ElfSection *getSection() { return section; }
};
class ElfSize: public ElfValue {
ElfSection *section;
public:
ElfSize(ElfSection *s): section(s) {};
unsigned int getValue();
ElfSection *getSection() { return section; }
};
class ElfEntSize: public ElfValue {
ElfSection *section;
public:
ElfEntSize(ElfSection *s): section(s) {};
unsigned int getValue();
ElfSection *getSection() { return section; }
};
template <typename T>
class serializable: public T::Type32 {
public:
serializable() {};
serializable(const typename T::Type32 &p): T::Type32(p) {};
private:
template <typename R>
void init(const char *buf, size_t len, char ei_data)
{
R e;
assert(len <= sizeof(e));
memcpy(&e, buf, sizeof(e));
if (ei_data == ELFDATA2LSB) {
T::template swap<little_endian>(e, *this);
return;
} else if (ei_data == ELFDATA2MSB) {
T::template swap<big_endian>(e, *this);
return;
}
throw std::runtime_error("Unsupported ELF data encoding");
}
public:
serializable(const char *buf, size_t len, char ei_class, char ei_data)
{
if (ei_class == ELFCLASS32) {
init<typename T::Type32>(buf, len, ei_data);
return;
} else if (ei_class == ELFCLASS64) {
init<typename T::Type64>(buf, len, ei_data);
return;
}
throw std::runtime_error("Unsupported ELF class");
}
serializable(std::ifstream &file, char ei_class, char ei_data)
{
if (ei_class == ELFCLASS32) {
typename T::Type32 e;
file.read((char *)&e, sizeof(e));
if (ei_data == ELFDATA2LSB) {
T::template swap<little_endian>(e, *this);
return;
} else if (ei_data == ELFDATA2MSB) {
T::template swap<big_endian>(e, *this);
return;
}
} else if (ei_class == ELFCLASS64) {
typename T::Type64 e;
file.read((char *)&e, sizeof(e));
if (ei_data == ELFDATA2LSB) {
T::template swap<little_endian>(e, *this);
return;
} else if (ei_data == ELFDATA2MSB) {
T::template swap<big_endian>(e, *this);
return;
}
}
throw std::runtime_error("Unsupported ELF class or data encoding");
}
void serialize(std::ofstream &file, char ei_class, char ei_data)
{
if (ei_class == ELFCLASS32) {
typename T::Type32 e;
if (ei_data == ELFDATA2LSB) {
T::template swap<little_endian>(*this, e);
file.write((char *)&e, sizeof(e));
return;
} else if (ei_data == ELFDATA2MSB) {
T::template swap<big_endian>(*this, e);
file.write((char *)&e, sizeof(e));
return;
}
} else if (ei_class == ELFCLASS64) {
typename T::Type64 e;
if (ei_data == ELFDATA2LSB) {
T::template swap<little_endian>(*this, e);
file.write((char *)&e, sizeof(e));
return;
} else if (ei_data == ELFDATA2MSB) {
T::template swap<big_endian>(*this, e);
file.write((char *)&e, sizeof(e));
return;
}
}
throw std::runtime_error("Unsupported ELF class or data encoding");
}
static inline unsigned int size(char ei_class)
{
if (ei_class == ELFCLASS32)
return sizeof(typename T::Type32);
else if (ei_class == ELFCLASS64)
return sizeof(typename T::Type64);
return 0;
}
};
typedef serializable<Elf_Shdr_Traits> Elf_Shdr;
class Elf {
public:
Elf(std::ifstream &file);
~Elf();
/* index == -1 is treated as index == ehdr.e_shstrndx */
ElfSection *getSection(int index);
ElfSection *getSectionAt(unsigned int offset);
ElfSegment *getSegmentByType(unsigned int type);
ElfDynamic_Section *getDynSection();
void write(std::ofstream &file);
char getClass();
char getData();
char getType();
char getMachine();
unsigned int getSize();
private:
Elf_Ehdr *ehdr;
ElfLocation eh_entry;
ElfStrtab_Section *eh_shstrndx;
ElfSection **sections;
std::vector<ElfSegment *> segments;
ElfSection *shdr_section, *phdr_section;
/* Values used only during initialization */
Elf_Shdr **tmp_shdr;
std::ifstream *tmp_file;
};
class ElfSection {
public:
typedef union {
ElfSection *section;
int index;
} SectionInfo;
ElfSection(Elf_Shdr &s, std::ifstream *file, Elf *parent);
virtual ~ElfSection() {
delete[] data;
}
const char *getName() { return name; }
unsigned int getType() { return shdr.sh_type; }
unsigned int getFlags() { return shdr.sh_flags; }
unsigned int getAddr();
unsigned int getSize() { return shdr.sh_size; }
unsigned int getAddrAlign() { return shdr.sh_addralign; }
unsigned int getEntSize() { return shdr.sh_entsize; }
const char *getData() { return data; }
ElfSection *getLink() { return link; }
SectionInfo getInfo() { return info; }
void shrink(unsigned int newsize) {
if (newsize < shdr.sh_size) {
shdr.sh_size = newsize;
if (next)
next->markDirty();
}
}
unsigned int getOffset();
int getIndex();
Elf_Shdr &getShdr();
ElfSection *getNext() { return next; }
ElfSection *getPrevious() { return previous; }
virtual bool isRelocatable() {
return ((getType() == SHT_SYMTAB) ||
(getType() == SHT_STRTAB) ||
(getType() == SHT_RELA) ||
(getType() == SHT_HASH) ||
(getType() == SHT_NOTE) ||
(getType() == SHT_REL) ||
(getType() == SHT_DYNSYM) ||
(getType() == SHT_GNU_HASH) ||
(getType() == SHT_GNU_verdef) ||
(getType() == SHT_GNU_verneed) ||
(getType() == SHT_GNU_versym) ||
isInSegmentType(PT_INTERP)) &&
(getFlags() & SHF_ALLOC);
}
void insertAfter(ElfSection *section, bool dirty = true) {
if (previous != NULL)
previous->next = next;
if (next != NULL)
next->previous = previous;
previous = section;
if (section != NULL) {
next = section->next;
section->next = this;
} else
next = NULL;
if (next != NULL)
next->previous = this;
if (dirty)
markDirty();
}
void markDirty() {
if (link != NULL)
shdr.sh_link = -1;
if (info.index)
shdr.sh_info = -1;
shdr.sh_offset = -1;
if (isRelocatable())
shdr.sh_addr = -1;
if (next)
next->markDirty();
}
virtual void serialize(std::ofstream &file, char ei_class, char ei_data)
{
if (getType() == SHT_NOBITS)
return;
file.seekp(getOffset());
file.write(data, getSize());
}
private:
friend class ElfSegment;
void addToSegment(ElfSegment *segment) {
segments.push_back(segment);
}
void removeFromSegment(ElfSegment *segment) {
std::vector<ElfSegment *>::iterator i = std::find(segments.begin(), segments.end(), segment);
segments.erase(i, i + 1);
}
bool isInSegmentType(unsigned int type);
protected:
Elf_Shdr shdr;
char *data;
const char *name;
private:
ElfSection *link;
SectionInfo info;
ElfSection *next, *previous;
int index;
std::vector<ElfSegment *> segments;
};
class ElfSegment {
public:
ElfSegment(Elf_Phdr *phdr);
unsigned int getType() { return type; }
unsigned int getFlags() { return flags; }
unsigned int getAlign() { return type == PT_LOAD ? 0x1000 : align; /* TODO: remove this gross hack */ }
ElfSection *getFirstSection() { return sections.empty() ? NULL : sections.front(); }
int getVPDiff() { return v_p_diff; }
unsigned int getFileSize();
unsigned int getMemSize();
unsigned int getOffset();
unsigned int getAddr();
void addSection(ElfSection *section);
std::list<ElfSection *>::iterator begin() { return sections.begin(); }
std::list<ElfSection *>::iterator end() { return sections.end(); }
ElfSegment *splitBefore(ElfSection *section);
private:
unsigned int type;
int v_p_diff; // Difference between physical and virtual address
unsigned int flags;
unsigned int align;
std::list<ElfSection *> sections;
// The following are only really used for PT_GNU_RELRO until something
// better is found.
unsigned int vaddr;
unsigned int filesz, memsz;
};
class Elf_Ehdr: public serializable<Elf_Ehdr_Traits>, public ElfSection {
public:
Elf_Ehdr(std::ifstream &file, char ei_class, char ei_data);
void serialize(std::ofstream &file, char ei_class, char ei_data)
{
serializable<Elf_Ehdr_Traits>::serialize(file, ei_class, ei_data);
}
};
class Elf_Phdr: public serializable<Elf_Phdr_Traits> {
public:
Elf_Phdr() {};
Elf_Phdr(std::ifstream &file, char ei_class, char ei_data)
: serializable<Elf_Phdr_Traits>(file, ei_class, ei_data) {};
bool contains(ElfSection *section)
{
unsigned int size = section->getSize();
unsigned int addr = section->getAddr();
// This may be biased, but should work in most cases
if ((section->getFlags() & SHF_ALLOC) == 0)
return false;
// Special case for PT_DYNAMIC. Eventually, this should
// be better handled than special cases
if ((p_type == PT_DYNAMIC) && (section->getType() != SHT_DYNAMIC))
return false;
// Special case for PT_TLS.
if ((p_type == PT_TLS) && !(section->getFlags() & SHF_TLS))
return false;
return (addr >= p_vaddr) &&
(addr + size <= p_vaddr + p_memsz);
}
};
typedef serializable<Elf_Dyn_Traits> Elf_Dyn;
struct Elf_DynValue {
unsigned int tag;
ElfValue *value;
};
class ElfDynamic_Section: public ElfSection {
public:
ElfDynamic_Section(Elf_Shdr &s, std::ifstream *file, Elf *parent);
~ElfDynamic_Section();
void serialize(std::ofstream &file, char ei_class, char ei_data);
ElfValue *getValueForType(unsigned int tag);
ElfSection *getSectionForType(unsigned int tag);
void setValueForType(unsigned int tag, ElfValue *val);
private:
std::vector<Elf_DynValue> dyns;
};
typedef serializable<Elf_Sym_Traits> Elf_Sym;
struct Elf_SymValue {
const char *name;
unsigned char info;
unsigned char other;
ElfLocation value;
unsigned int size;
bool defined;
};
#define STT(type) (1 << STT_ ##type)
class ElfSymtab_Section: public ElfSection {
public:
ElfSymtab_Section(Elf_Shdr &s, std::ifstream *file, Elf *parent);
void serialize(std::ofstream &file, char ei_class, char ei_data);
Elf_SymValue *lookup(const char *name, unsigned int type_filter = STT(OBJECT) | STT(FUNC));
//private: // Until we have a real API
std::vector<Elf_SymValue> syms;
};
class Elf_Rel: public serializable<Elf_Rel_Traits> {
public:
Elf_Rel(std::ifstream &file, char ei_class, char ei_data)
: serializable<Elf_Rel_Traits>(file, ei_class, ei_data) {};
static const unsigned int sh_type = SHT_REL;
static const unsigned int d_tag = DT_REL;
static const unsigned int d_tag_count = DT_RELCOUNT;
};
class Elf_Rela: public serializable<Elf_Rela_Traits> {
public:
Elf_Rela(std::ifstream &file, char ei_class, char ei_data)
: serializable<Elf_Rela_Traits>(file, ei_class, ei_data) {};
static const unsigned int sh_type = SHT_RELA;
static const unsigned int d_tag = DT_RELA;
static const unsigned int d_tag_count = DT_RELACOUNT;
};
template <class Rel>
class ElfRel_Section: public ElfSection {
public:
ElfRel_Section(Elf_Shdr &s, std::ifstream *file, Elf *parent)
: ElfSection(s, file, parent)
{
int pos = file->tellg();
file->seekg(shdr.sh_offset);
for (unsigned int i = 0; i < s.sh_size / s.sh_entsize; i++) {
Rel r(*file, parent->getClass(), parent->getData());
rels.push_back(r);
}
file->seekg(pos);
}
void serialize(std::ofstream &file, char ei_class, char ei_data)
{
for (typename std::vector<Rel>::iterator i = rels.begin();
i != rels.end(); ++i)
(*i).serialize(file, ei_class, ei_data);
}
//private: // Until we have a real API
std::vector<Rel> rels;
};
class ElfStrtab_Section: public ElfSection {
public:
ElfStrtab_Section(Elf_Shdr &s, std::ifstream *file, Elf *parent)
: ElfSection(s, file, parent)
{
table.push_back(table_storage(data, shdr.sh_size));
}
~ElfStrtab_Section()
{
for (std::vector<table_storage>::iterator t = table.begin() + 1;
t != table.end(); t++)
delete[] t->buf;
}
const char *getStr(unsigned int index);
const char *getStr(const char *string);
unsigned int getStrIndex(const char *string);
void serialize(std::ofstream &file, char ei_class, char ei_data);
private:
struct table_storage {
unsigned int size, used;
char *buf;
table_storage(): size(4096), used(0), buf(new char[4096]) {}
table_storage(const char *data, unsigned int sz)
: size(sz), used(sz), buf(const_cast<char *>(data)) {}
};
std::vector<table_storage> table;
};
inline char Elf::getClass() {
return ehdr->e_ident[EI_CLASS];
}
inline char Elf::getData() {
return ehdr->e_ident[EI_DATA];
}
inline char Elf::getType() {
return ehdr->e_type;
}
inline char Elf::getMachine() {
return ehdr->e_machine;
}
inline unsigned int Elf::getSize() {
ElfSection *section;
for (section = shdr_section /* It's usually not far from the end */;
section->getNext() != NULL; section = section->getNext());
return section->getOffset() + section->getSize();
}
inline bool ElfSection::isInSegmentType(unsigned int type) {
for (std::vector<ElfSegment *>::iterator seg = segments.begin(); seg != segments.end(); seg++)
if ((*seg)->getType() == type)
return true;
return false;
}
inline ElfLocation::ElfLocation(ElfSection *section, unsigned int off, enum position pos)
: section(section) {
if ((pos == ABSOLUTE) && section)
offset = off - section->getAddr();
else
offset = off;
}
inline ElfLocation::ElfLocation(unsigned int location, Elf *elf) {
section = elf->getSectionAt(location);
offset = location - (section ? section->getAddr() : 0);
}
inline unsigned int ElfLocation::getValue() {
return (section ? section->getAddr() : 0) + offset;
}
inline unsigned int ElfSize::getValue() {
return section->getSize();
}
inline unsigned int ElfEntSize::getValue() {
return section->getEntSize();
}
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