Merge pull request #22 from bunnei/loader-improvements

Refactor loader code and add preliminary NCCH support

1 files changed, 370 insertions, 0 deletions

diff --git a/src/core/loader/elf.cpp b/src/core/loader/elf.cpp
new file mode 100644
index 000000000..76c9d6d54
--- /dev/null
+++ b/src/core/loader/elf.cpp
@@ -0,0 +1,370 @@
+// Copyright 2013 Dolphin Emulator Project
+// Licensed under GPLv2
+// Refer to the license.txt file included.
+
+#include <string>
+#include <memory>
+
+#include "common/common.h"
+#include "common/file_util.h"
+#include "common/symbols.h"
+
+#include "core/mem_map.h"
+#include "core/loader/elf.h"
+#include "core/hle/kernel/kernel.h"
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+// ELF Header Constants
+
+// File type
+enum ElfType {
+    ET_NONE = 0,
+    ET_REL = 1,
+    ET_EXEC = 2,
+    ET_DYN = 3,
+    ET_CORE = 4,
+    ET_LOPROC = 0xFF00,
+    ET_HIPROC = 0xFFFF,
+};
+
+// Machine/Architecture
+enum ElfMachine {
+    EM_NONE = 0,
+    EM_M32 = 1,
+    EM_SPARC = 2,
+    EM_386 = 3,
+    EM_68K = 4,
+    EM_88K = 5,
+    EM_860 = 7,
+    EM_MIPS = 8
+};
+
+// File version
+#define EV_NONE    0
+#define EV_CURRENT 1
+
+// Identification index
+#define EI_MAG0    0
+#define EI_MAG1    1
+#define EI_MAG2    2
+#define EI_MAG3    3
+#define EI_CLASS   4
+#define EI_DATA    5
+#define EI_VERSION 6
+#define EI_PAD     7
+#define EI_NIDENT 16
+
+// Magic number
+#define ELFMAG0 0x7F
+#define ELFMAG1  'E'
+#define ELFMAG2  'L'
+#define ELFMAG3  'F'
+
+// Sections constants
+
+// Section types
+#define SHT_NULL            0
+#define SHT_PROGBITS        1
+#define SHT_SYMTAB          2
+#define SHT_STRTAB          3
+#define SHT_RELA            4
+#define SHT_HASH            5
+#define SHT_DYNAMIC         6
+#define SHT_NOTE            7
+#define SHT_NOBITS          8
+#define SHT_REL             9
+#define SHT_SHLIB          10
+#define SHT_DYNSYM         11
+#define SHT_LOPROC 0x70000000
+#define SHT_HIPROC 0x7FFFFFFF
+#define SHT_LOUSER 0x80000000
+#define SHT_HIUSER 0xFFFFFFFF
+
+// Section flags
+enum ElfSectionFlags
+{
+    SHF_WRITE = 0x1,
+    SHF_ALLOC = 0x2,
+    SHF_EXECINSTR = 0x4,
+    SHF_MASKPROC = 0xF0000000,
+};
+
+// Segment types
+#define PT_NULL             0
+#define PT_LOAD             1
+#define PT_DYNAMIC          2
+#define PT_INTERP           3
+#define PT_NOTE             4
+#define PT_SHLIB            5
+#define PT_PHDR             6
+#define PT_LOPROC  0x70000000
+#define PT_HIPROC  0x7FFFFFFF
+
+typedef unsigned int  Elf32_Addr;
+typedef unsigned short Elf32_Half;
+typedef unsigned int  Elf32_Off;
+typedef signed   int  Elf32_Sword;
+typedef unsigned int  Elf32_Word;
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+// ELF file header
+
+struct Elf32_Ehdr {
+    unsigned char e_ident[EI_NIDENT];
+    Elf32_Half    e_type;
+    Elf32_Half    e_machine;
+    Elf32_Word    e_version;
+    Elf32_Addr    e_entry;
+    Elf32_Off     e_phoff;
+    Elf32_Off     e_shoff;
+    Elf32_Word    e_flags;
+    Elf32_Half    e_ehsize;
+    Elf32_Half    e_phentsize;
+    Elf32_Half    e_phnum;
+    Elf32_Half    e_shentsize;
+    Elf32_Half    e_shnum;
+    Elf32_Half    e_shstrndx;
+};
+
+// Section header
+struct Elf32_Shdr {
+    Elf32_Word sh_name;
+    Elf32_Word sh_type;
+    Elf32_Word sh_flags;
+    Elf32_Addr sh_addr;
+    Elf32_Off  sh_offset;
+    Elf32_Word sh_size;
+    Elf32_Word sh_link;
+    Elf32_Word sh_info;
+    Elf32_Word sh_addralign;
+    Elf32_Word sh_entsize;
+};
+
+// Segment header
+struct Elf32_Phdr {
+    Elf32_Word p_type;
+    Elf32_Off  p_offset;
+    Elf32_Addr p_vaddr;
+    Elf32_Addr p_paddr;
+    Elf32_Word p_filesz;
+    Elf32_Word p_memsz;
+    Elf32_Word p_flags;
+    Elf32_Word p_align;
+};
+
+// Symbol table entry
+struct Elf32_Sym {
+    Elf32_Word    st_name;
+    Elf32_Addr    st_value;
+    Elf32_Word    st_size;
+    unsigned char st_info;
+    unsigned char st_other;
+    Elf32_Half    st_shndx;
+};
+
+// Relocation entries
+struct Elf32_Rel {
+    Elf32_Addr r_offset;
+    Elf32_Word r_info;
+};
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+// ElfReader class
+
+typedef int SectionID;
+
+class ElfReader {
+private:
+    char *base;
+    u32 *base32;
+
+    Elf32_Ehdr *header;
+    Elf32_Phdr *segments;
+    Elf32_Shdr *sections;
+
+    u32 *sectionAddrs;
+    bool relocate;
+    u32 entryPoint;
+
+public:
+    ElfReader(void *ptr);
+    ~ElfReader() { }
+
+    u32 Read32(int off) const { return base32[off >> 2]; }
+
+    // Quick accessors
+    ElfType GetType() const { return (ElfType)(header->e_type); }
+    ElfMachine GetMachine() const { return (ElfMachine)(header->e_machine); }
+    u32 GetEntryPoint() const { return entryPoint; }
+    u32 GetFlags() const { return (u32)(header->e_flags); }
+    bool LoadInto(u32 vaddr);
+    bool LoadSymbols();
+
+    int GetNumSegments() const { return (int)(header->e_phnum); }
+    int GetNumSections() const { return (int)(header->e_shnum); }
+    const u8 *GetPtr(int offset) const { return (u8*)base + offset; }
+    const char *GetSectionName(int section) const;
+    const u8 *GetSectionDataPtr(int section) const {
+        if (section < 0 || section >= header->e_shnum)
+            return nullptr;
+        if (sections[section].sh_type != SHT_NOBITS)
+            return GetPtr(sections[section].sh_offset);
+        else
+            return nullptr;
+    }
+    bool IsCodeSection(int section) const {
+        return sections[section].sh_type == SHT_PROGBITS;
+    }
+    const u8 *GetSegmentPtr(int segment) {
+        return GetPtr(segments[segment].p_offset);
+    }
+    u32 GetSectionAddr(SectionID section) const { return sectionAddrs[section]; }
+    int GetSectionSize(SectionID section) const { return sections[section].sh_size; }
+    SectionID GetSectionByName(const char *name, int firstSection = 0) const; //-1 for not found
+
+    bool DidRelocate() {
+        return relocate;
+    }
+};
+
+ElfReader::ElfReader(void *ptr) {
+    base = (char*)ptr;
+    base32 = (u32 *)ptr;
+    header = (Elf32_Ehdr*)ptr;
+
+    segments = (Elf32_Phdr *)(base + header->e_phoff);
+    sections = (Elf32_Shdr *)(base + header->e_shoff);
+
+    entryPoint = header->e_entry;
+
+    LoadSymbols();
+}
+
+const char *ElfReader::GetSectionName(int section) const {
+    if (sections[section].sh_type == SHT_NULL)
+        return nullptr;
+
+    int name_offset = sections[section].sh_name;
+    char *ptr = (char*)GetSectionDataPtr(header->e_shstrndx);
+
+    if (ptr)
+        return ptr + name_offset;
+
+    return nullptr;
+}
+
+bool ElfReader::LoadInto(u32 vaddr) {
+    DEBUG_LOG(MASTER_LOG, "String section: %i", header->e_shstrndx);
+
+    // Should we relocate?
+    relocate = (header->e_type != ET_EXEC);
+
+    if (relocate) {
+        DEBUG_LOG(MASTER_LOG, "Relocatable module");
+        entryPoint += vaddr;
+    } else {
+        DEBUG_LOG(MASTER_LOG, "Prerelocated executable");
+    }
+    INFO_LOG(MASTER_LOG, "%i segments:", header->e_phnum);
+
+    // First pass : Get the bits into RAM
+    u32 segment_addr[32];
+    u32 base_addr = relocate ? vaddr : 0;
+
+    for (int i = 0; i < header->e_phnum; i++) {
+        Elf32_Phdr *p = segments + i;
+        INFO_LOG(MASTER_LOG, "Type: %i Vaddr: %08x Filesz: %i Memsz: %i ", p->p_type, p->p_vaddr, 
+            p->p_filesz, p->p_memsz);
+
+        if (p->p_type == PT_LOAD) {
+            segment_addr[i] = base_addr + p->p_vaddr;
+            memcpy(Memory::GetPointer(segment_addr[i]), GetSegmentPtr(i), p->p_filesz);
+            INFO_LOG(MASTER_LOG, "Loadable Segment Copied to %08x, size %08x", segment_addr[i], 
+                p->p_memsz);
+        }
+    }
+    INFO_LOG(MASTER_LOG, "Done loading.");
+    return true;
+}
+
+SectionID ElfReader::GetSectionByName(const char *name, int firstSection) const {
+    for (int i = firstSection; i < header->e_shnum; i++) {
+        const char *secname = GetSectionName(i);
+
+        if (secname != nullptr && strcmp(name, secname) == 0)
+            return i;
+    }
+    return -1;
+}
+
+bool ElfReader::LoadSymbols() {
+    bool hasSymbols = false;
+    SectionID sec = GetSectionByName(".symtab");
+    if (sec != -1) {
+        int stringSection = sections[sec].sh_link;
+        const char *stringBase = (const char *)GetSectionDataPtr(stringSection);
+
+        //We have a symbol table!
+        Elf32_Sym *symtab = (Elf32_Sym *)(GetSectionDataPtr(sec));
+        int numSymbols = sections[sec].sh_size / sizeof(Elf32_Sym);
+        for (int sym = 0; sym < numSymbols; sym++) {
+            int size = symtab[sym].st_size;
+            if (size == 0)
+                continue;
+
+            int type = symtab[sym].st_info & 0xF;
+
+            const char *name = stringBase + symtab[sym].st_name;
+
+            Symbols::Add(symtab[sym].st_value, name, size, type);
+
+            hasSymbols = true;
+        }
+    }
+
+    return hasSymbols;
+}
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+// Loader namespace
+
+namespace Loader {
+
+/// AppLoader_ELF constructor
+AppLoader_ELF::AppLoader_ELF(const std::string& filename) : is_loaded(false) {
+    this->filename = filename;
+}
+
+/// AppLoader_NCCH destructor
+AppLoader_ELF::~AppLoader_ELF() {
+}
+
+/**
+ * Loads an NCCH file (e.g. from a CCI, or the first NCCH in a CXI)
+ * @param error_string Pointer to string to put error message if an error has occurred
+ * @todo Move NCSD parsing out of here and create a separate function for loading these
+ * @return True on success, otherwise false
+ */
+ResultStatus AppLoader_ELF::Load() {
+    INFO_LOG(LOADER, "Loading ELF file %s...", filename.c_str());
+
+    if (is_loaded)
+        return ResultStatus::ErrorAlreadyLoaded;
+
+    File::IOFile file(filename, "rb");
+
+    if (file.IsOpen()) {
+        u32 size = (u32)file.GetSize();
+        std::unique_ptr<u8[]> buffer(new u8[size]);
+        file.ReadBytes(&buffer[0], size);
+
+        ElfReader elf_reader(&buffer[0]);
+        elf_reader.LoadInto(0x00100000);
+        Kernel::LoadExec(elf_reader.GetEntryPoint());
+    } else {
+        return ResultStatus::Error;
+    }
+    return ResultStatus::Success;
+}
+
+} // namespace Loader