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//! Hikari ELF Loader
const efi = @import("../../efi/efi.zig");
const constants = @import("constants.zig");
const types = @import("types.zig");
pub const LoadError = error{
invalid_elf_header,
unsupported_architecture,
unsupported_elf_type,
no_loadable_segments,
too_many_segments,
allocation_failed,
segment_overlap,
};
pub const Loader = struct {
boot_services: *efi.services.BootServices,
pub fn initialize(boot_services: *efi.services.BootServices) Loader {
return Loader{
.boot_services = boot_services,
};
}
pub fn load(self: *Loader, unit_data: [*]const u8, unit_size: u64) LoadError!types.LoadedImage {
if (unit_size < constants.elf64_header_size) {
return LoadError.invalid_elf_header;
}
const header: *const types.Elf64Header = @ptrCast(@alignCast(unit_data));
if (!header.is_valid()) {
return LoadError.invalid_elf_header;
}
if (!header.is_x86_64()) {
return LoadError.unsupported_architecture;
}
if (!header.is_executable()) {
return LoadError.unsupported_elf_type;
}
const program_headers = header.get_program_headers(unit_data);
var load_base: u64 = 0xFFFFFFFFFFFFFFFF;
var load_end: u64 = 0;
var loadable_count: usize = 0;
for (program_headers) |*phdr| {
if (!phdr.is_loadable()) {
continue;
}
loadable_count += 1;
if (phdr.virtual_address < load_base) {
load_base = phdr.virtual_address;
}
const segment_end = phdr.virtual_address + phdr.memory_size;
if (segment_end > load_end) {
load_end = segment_end;
}
}
if (loadable_count == 0) {
return LoadError.no_loadable_segments;
}
if (loadable_count > 16) {
return LoadError.too_many_segments;
}
const total_size = load_end - load_base;
const pages_needed = (total_size + 4095) / 4096;
var physical_base: efi.types.PhysicalAddress = load_base;
const alloc_status = self.boot_services.allocate_pages(
.address,
.loader_data,
pages_needed,
&physical_base,
);
if (efi.types.is_error(alloc_status)) {
physical_base = 0;
const fallback_status = self.boot_services.allocate_pages(
.any_pages,
.loader_data,
pages_needed,
&physical_base,
);
if (efi.types.is_error(fallback_status)) {
return LoadError.allocation_failed;
}
}
const dest_base: [*]u8 = @ptrFromInt(physical_base);
var i: u64 = 0;
while (i < total_size) : (i += 1) {
dest_base[i] = 0;
}
var image = types.LoadedImage{
.entry_point = header.entry,
.base_address = physical_base,
.end_address = physical_base + total_size,
.segments = undefined,
.segment_count = 0,
};
for (program_headers) |*phdr| {
if (!phdr.is_loadable()) {
continue;
}
const segment_offset = phdr.virtual_address - load_base;
const dest: [*]u8 = dest_base + segment_offset;
const src = unit_data + phdr.offset;
var j: u64 = 0;
while (j < phdr.unit_size) : (j += 1) {
dest[j] = src[j];
}
image.segments[image.segment_count] = types.LoadedSegment{
.virtual_address = phdr.virtual_address,
.physical_address = physical_base + segment_offset,
.memory_size = phdr.memory_size,
.flags = phdr.flags,
};
image.segment_count += 1;
}
if (physical_base != load_base) {
image.entry_point = (header.entry - load_base) + physical_base;
}
return image;
}
pub fn get_memory_requirements(unit_data: [*]const u8) LoadError!struct { base: u64, size: u64 } {
const header: *const types.Elf64Header = @ptrCast(@alignCast(unit_data));
if (!header.is_valid()) {
return LoadError.invalid_elf_header;
}
const program_headers = header.get_program_headers(unit_data);
var load_base: u64 = 0xFFFFFFFFFFFFFFFF;
var load_end: u64 = 0;
for (program_headers) |*phdr| {
if (!phdr.is_loadable()) {
continue;
}
if (phdr.virtual_address < load_base) {
load_base = phdr.virtual_address;
}
const segment_end = phdr.virtual_address + phdr.memory_size;
if (segment_end > load_end) {
load_end = segment_end;
}
}
if (load_base == 0xFFFFFFFFFFFFFFFF) {
return LoadError.no_loadable_segments;
}
return .{
.base = load_base,
.size = load_end - load_base,
};
}
pub fn get_entry_point(unit_data: [*]const u8) LoadError!u64 {
const header: *const types.Elf64Header = @ptrCast(@alignCast(unit_data));
if (!header.is_valid()) {
return LoadError.invalid_elf_header;
}
return header.entry;
}
};
pub fn validate_elf(data: [*]const u8, size: u64) bool {
if (size < constants.elf64_header_size) {
return false;
}
const header: *const types.Elf64Header = @ptrCast(@alignCast(data));
return header.is_valid() and header.is_x86_64();
}
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