#include "exe.h"

#include "elf.h"

static enum ec3_status get_elf_executable_info(
	FILE *fp,
	struct ec3_tag_executable_info *out)
{
	elf_ehdr_t hdr;
	fseek(fp, 0, SEEK_SET);
	size_t r = fread(&hdr, sizeof hdr, 1, fp);
	if (r != 1) {
		return EC3_ERR_IO_FAILURE;
	}

	out->exe_elf.elf_entry = hdr.e_entry;

	bool text_found = false, data_found = false;

	for (size_t i = 0; i < hdr.e_phnum; i++) {
		elf_phdr_t phdr;
		size_t offset = hdr.e_phoff + (i * hdr.e_phentsize);
		fseek(fp, offset, SEEK_SET);
		r = fread(&phdr, sizeof phdr, 1, fp);

		if (r != 1) {
			return EC3_ERR_IO_FAILURE;
		}

		if (phdr.p_type != PT_LOAD) {
			continue;
		}

		if ((phdr.p_flags & (PF_R | PF_X)) == (PF_R | PF_X)) {
			if (text_found) {
				out->exe_format = EC3_EXEC_OTHER;
				return EC3_SUCCESS;
			}

			out->exe_elf.elf_text_offset = phdr.p_offset;
			out->exe_elf.elf_text_filesz = phdr.p_filesz;
			out->exe_elf.elf_text_vaddr = phdr.p_vaddr;
			out->exe_elf.elf_text_memsz = phdr.p_memsz;
			out->exe_elf.elf_text_align = phdr.p_align;
			text_found = true;
		}

		if ((phdr.p_flags & (PF_R | PF_W)) == (PF_R | PF_W)) {
			if (data_found) {
				out->exe_format = EC3_EXEC_OTHER;
				return EC3_SUCCESS;
			}

			out->exe_elf.elf_data_offset = phdr.p_offset;
			out->exe_elf.elf_data_filesz = phdr.p_filesz;
			out->exe_elf.elf_data_vaddr = phdr.p_vaddr;
			out->exe_elf.elf_data_memsz = phdr.p_memsz;
			out->exe_elf.elf_data_align = phdr.p_align;
			data_found = true;
		}
	}

	return EC3_SUCCESS;
}

enum ec3_status get_executable_info_from_file(
	FILE *fp,
	enum ec3_executable_format format,
	struct ec3_tag_executable_info *out)
{
	out->exe_format = format;

	switch (format) {
	case EC3_EXEC_ELF:
		return get_elf_executable_info(fp, out);
	default:
		return EC3_SUCCESS;
	}
}