Method Init

contrib/stacktrace/stacktrace.amalgamation.cpp:2412–2533

}

void ElfMemImage::Init(const void* base) {
	ehdr_ = nullptr;
	dynsym_ = nullptr;
	dynstr_ = nullptr;
	versym_ = nullptr;
	verdef_ = nullptr;
	hash_ = nullptr;
	strsize_ = 0;
	verdefnum_ = 0;
	link_base_ = ~0L; // Sentinel: PT_LOAD .p_vaddr can't possibly be this.
	if (!base) {
		return;
	}
	const intptr_t base_as_uintptr_t = reinterpret_cast<uintptr_t>(base);
	// Fake VDSO has low bit set.
	const bool fake_vdso = ((base_as_uintptr_t & 1) != 0);
	base = reinterpret_cast<const void*>(base_as_uintptr_t & ~1);
	const char* const base_as_char = reinterpret_cast<const char*>(base);
	if (base_as_char[EI_MAG0] != ELFMAG0 || base_as_char[EI_MAG1] != ELFMAG1 || base_as_char[EI_MAG2] != ELFMAG2 ||
	    base_as_char[EI_MAG3] != ELFMAG3) {
		assert(false);
		return;
	}
	int elf_class = base_as_char[EI_CLASS];
	if (elf_class != kElfClass) {
		assert(false);
		return;
	}
	switch (base_as_char[EI_DATA]) {
	case ELFDATA2LSB: {
		if (__LITTLE_ENDIAN != __BYTE_ORDER) {
			assert(false);
			return;
		}
		break;
	}
	case ELFDATA2MSB: {
		if (__BIG_ENDIAN != __BYTE_ORDER) {
			assert(false);
			return;
		}
		break;
	}
	default: {
		assert(false);
		return;
	}
	}

	ehdr_ = reinterpret_cast<const ElfW(Ehdr)*>(base);
	const ElfW(Phdr)* dynamic_program_header = nullptr;
	for (int i = 0; i < ehdr_->e_phnum; ++i) {
		const ElfW(Phdr)* const program_header = GetPhdr(i);
		switch (program_header->p_type) {
		case PT_LOAD:
			if (!~link_base_) {
				link_base_ = program_header->p_vaddr;
			}