1 files changed, 701 insertions, 0 deletions

diff --git a/build/unix/elfhack/elfxx.h b/build/unix/elfhack/elfxx.h
new file mode 100644
index 000000000..a05b02348
--- /dev/null
+++ b/build/unix/elfhack/elfxx.h
@@ -0,0 +1,701 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#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 nullptr; }
+};
+
+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(nullptr), 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; }
+    const char *getBuffer();
+};
+
+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");
+    }
+
+    template <typename R>
+    void serialize(const char *buf, size_t len, char ei_data)
+    {
+        assert(len >= sizeof(R));
+        if (ei_data == ELFDATA2LSB) {
+            T::template swap<little_endian>(*this, *(R *)buf);
+            return;
+        } else if (ei_data == ELFDATA2MSB) {
+            T::template swap<big_endian>(*this, *(R *)buf);
+            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));
+            init<typename T::Type32>((char *)&e, sizeof(e), ei_data);
+            return;
+        } else if (ei_class == ELFCLASS64) {
+            typename T::Type64 e;
+            file.read((char *)&e, sizeof(e));
+            init<typename T::Type64>((char *)&e, sizeof(e), ei_data);
+            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;
+            serialize<typename T::Type32>((char *)&e, sizeof(e), ei_data);
+            file.write((char *)&e, sizeof(e));
+            return;
+        } else if (ei_class == ELFCLASS64) {
+            typename T::Type64 e;
+            serialize<typename T::Type64>((char *)&e, sizeof(e), ei_data);
+            file.write((char *)&e, sizeof(e));
+            return;
+        }
+        throw std::runtime_error("Unsupported ELF class or data encoding");
+    }
+
+    void serialize(char *buf, size_t len, char ei_class, char ei_data)
+    {
+        if (ei_class == ELFCLASS32) {
+            serialize<typename T::Type32>(buf, len, ei_data);
+            return;
+        } else if (ei_class == ELFCLASS64) {
+            serialize<typename T::Type64>(buf, len, ei_data);
+            return;
+        }
+        throw std::runtime_error("Unsupported ELF class");
+    }
+
+    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, ElfSegment *last = nullptr);
+
+    ElfDynamic_Section *getDynSection();
+
+    void normalize();
+    void write(std::ofstream &file);
+
+    char getClass();
+    char getData();
+    char getType();
+    char getMachine();
+    unsigned int getSize();
+
+    void insertSegmentAfter(ElfSegment *previous, ElfSegment *segment) {
+        std::vector<ElfSegment *>::iterator prev = std::find(segments.begin(), segments.end(), previous);
+        segments.insert(prev + 1, segment);
+    }
+
+    void removeSegment(ElfSegment *segment);
+
+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;
+    }
+
+    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) ||
+                getSegmentByType(PT_INTERP)) &&
+                (getFlags() & SHF_ALLOC);
+    }
+
+    void insertAfter(ElfSection *section, bool dirty = true) {
+        if (previous != nullptr)
+            previous->next = next;
+        if (next != nullptr)
+            next->previous = previous;
+        previous = section;
+        if (section != nullptr) {
+            next = section->next;
+            section->next = this;
+        } else
+            next = nullptr;
+        if (next != nullptr)
+            next->previous = this;
+        if (dirty)
+            markDirty();
+        insertInSegments(section->segments);
+    }
+
+    void insertBefore(ElfSection *section, bool dirty = true) {
+        if (previous != nullptr)
+            previous->next = next;
+        if (next != nullptr)
+            next->previous = previous;
+        next = section;
+        if (section != nullptr) {
+            previous = section->previous;
+            section->previous = this;
+        } else
+            previous = nullptr;
+        if (previous != nullptr)
+            previous->next = this;
+        if (dirty)
+            markDirty();
+        insertInSegments(section->segments);
+    }
+
+    void markDirty() {
+        if (link != nullptr)
+            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);
+    }
+
+    ElfSegment *getSegmentByType(unsigned int type);
+
+    void insertInSegments(std::vector<ElfSegment *> &segs);
+
+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 align; }
+
+    ElfSection *getFirstSection() { return sections.empty() ? nullptr : sections.front(); }
+    int getVPDiff() { return v_p_diff; }
+    unsigned int getFileSize();
+    unsigned int getMemSize();
+    unsigned int getOffset();
+    unsigned int getAddr();
+
+    void addSection(ElfSection *section);
+    void removeSection(ElfSection *section);
+
+    std::list<ElfSection *>::iterator begin() { return sections.begin(); }
+    std::list<ElfSection *>::iterator end() { return sections.end(); }
+
+    void clear();
+
+    bool isElfHackFillerSegment() {
+      return type == PT_LOAD && flags == 0;
+    }
+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);
+    bool 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() != nullptr; section = section->getNext());
+    return section->getOffset() + section->getSize();
+}
+
+inline ElfSegment *ElfSection::getSegmentByType(unsigned int type) {
+    for (std::vector<ElfSegment *>::iterator seg = segments.begin(); seg != segments.end(); seg++)
+        if ((*seg)->getType() == type)
+            return *seg;
+    return nullptr;
+}
+
+inline void ElfSection::insertInSegments(std::vector<ElfSegment *> &segs) {
+    for (std::vector<ElfSegment *>::iterator it = segs.begin(); it != segs.end(); ++it) {
+        (*it)->addSection(this);
+    }
+}
+
+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 const char *ElfLocation::getBuffer() {
+    return section ? section->getData() + offset : nullptr;
+}
+
+inline unsigned int ElfSize::getValue() {
+    return section->getSize();
+}
+
+inline unsigned int ElfEntSize::getValue() {
+    return section->getEntSize();
+}