Implement ELF support

PowerUtils/image.cpp

@@ -0,0 +1,91 @@
+#include "image.h"
+#include "elf.h"
+#include "xex.h"
+#include <cassert>
+
+void Image::Map(const std::string_view& name, size_t base, uint32_t size, uint8_t flags, uint8_t* data)
+{
+    sections.emplace_back(std::string(name), this->base + base, 
+        size, static_cast<SectionFlags>(flags), data);
+}
+
+const void* Image::Find(size_t address) const
+{
+    for (const auto& section : sections)
+    {
+        if (section == address)
+        {
+            return section.data + (address - section.base);
+        }
+    }
+
+    return nullptr;
+}
+
+std::expected<Image, int> Image::ParseImage(const uint8_t* data, size_t size)
+{
+    if (data[0] == ELFMAG0 && data[1] == ELFMAG1 && data[2] == ELFMAG2 && data[3] == ELFMAG3)
+    {
+        return ElfLoadImage(data, size);
+    }
+    else if (data[0] == 'X' && data[1] == 'E' && data[0] == 'X' && data[0] == '2')
+    {
+        return Xex2LoadImage(data);
+    }
+
+    return std::unexpected(1);
+}
+
+Image ElfLoadImage(const uint8_t* data, size_t size)
+{
+    const auto* header = (elf32_hdr*)data;
+    assert(header->e_ident[EI_DATA] == 2);
+
+    Image image{};
+    image.size = size;
+    image.data = std::make_unique<uint8_t[]>(size);
+    memcpy(image.data.get(), data, size);
+
+    auto stringTableIndex = std::byteswap(header->e_shstrndx);
+
+    const auto numSections = std::byteswap(header->e_shnum);
+    const auto numpSections = std::byteswap(header->e_phnum);
+
+    const auto* sections = (elf32_shdr*)(data + std::byteswap(header->e_shoff));
+    const auto* psections = (elf32_phdr*)(data + std::byteswap(header->e_phoff));
+
+    for (size_t i = 0; i < numpSections; i++)
+    {
+        if (psections[i].p_type == std::byteswap((Elf32_Word)PT_LOAD))
+        {
+            image.base = psections[i].p_vaddr;
+            break;
+        }
+    }
+
+    auto* stringTable = reinterpret_cast<const char*>(data + std::byteswap(sections[stringTableIndex].sh_offset));
+
+    for (size_t i = 0; i < numSections; i++)
+    {
+        const auto& section = sections[i];
+        if (section.sh_type == 0)
+        {
+            continue;
+        }
+
+        uint8_t flags{};
+
+        if (section.sh_flags & std::byteswap(SHF_EXECINSTR))
+        {
+            flags |= SectionFlags_Code;
+        }
+
+        auto* name = section.sh_name != 0 ? stringTable + std::byteswap(section.sh_name) : nullptr;
+        const auto rva = std::byteswap(section.sh_addr) - image.base;
+        const auto size = std::byteswap(section.sh_size);
+
+        image.Map(name, rva, size, flags, image.data.get() + std::byteswap(section.sh_offset));
+    }
+
+    return image;
+}