const std = @import("../../../std.zig");
const mem = std.mem;
const uefi = std.os.uefi;
const Allocator = mem.Allocator;
const Guid = uefi.Guid;
const assert = std.debug.assert;
pub const DevicePath = extern struct {
type: uefi.DevicePath.Type,
subtype: u8,
length: u16 align(1),
pub const guid align(8) = Guid{
.time_low = 0x09576e91,
.time_mid = 0x6d3f,
.time_high_and_version = 0x11d2,
.clock_seq_high_and_reserved = 0x8e,
.clock_seq_low = 0x39,
.node = [_]u8{ 0x00, 0xa0, 0xc9, 0x69, 0x72, 0x3b },
};
pub fn next(self: *DevicePath) ?*DevicePath {
if (self.type == .End and @as(uefi.DevicePath.End.Subtype, @enumFromInt(self.subtype)) == .EndEntire)
return null;
return @as(*DevicePath, @ptrCast(@as([*]u8, @ptrCast(self)) + self.length));
}
pub fn size(self: *DevicePath) usize {
var node = self;
while (node.next()) |next_node| {
node = next_node;
}
return (@intFromPtr(node) + node.length) - @intFromPtr(self);
}
pub fn create_file_device_path(self: *DevicePath, allocator: Allocator, path: [:0]align(1) const u16) !*DevicePath {
var path_size = self.size();
var buf = try allocator.alloc(u8, path_size + 2 * (path.len + 1) + @sizeOf(DevicePath));
@memcpy(buf[0..path_size], @as([*]const u8, @ptrCast(self))[0..path_size]);
var new = @as(*uefi.DevicePath.Media.FilePathDevicePath, @ptrCast(buf.ptr + path_size - 4));
new.type = .Media;
new.subtype = .FilePath;
new.length = @sizeOf(uefi.DevicePath.Media.FilePathDevicePath) + 2 * (@as(u16, @intCast(path.len)) + 1);
var ptr = @as([*:0]align(1) u16, @ptrCast(@as([*]u8, @ptrCast(new)) + @sizeOf(uefi.DevicePath.Media.FilePathDevicePath)));
for (path, 0..) |s, i|
ptr[i] = s;
ptr[path.len] = 0;
var end = @as(*uefi.DevicePath.End.EndEntireDevicePath, @ptrCast(@as(*DevicePath, @ptrCast(new)).next().?));
end.type = .End;
end.subtype = .EndEntire;
end.length = @sizeOf(uefi.DevicePath.End.EndEntireDevicePath);
return @as(*DevicePath, @ptrCast(buf.ptr));
}
pub fn getDevicePath(self: *const DevicePath) ?uefi.DevicePath {
inline for (@typeInfo(uefi.DevicePath).Union.fields) |ufield| {
const enum_value = std.meta.stringToEnum(uefi.DevicePath.Type, ufield.name);
if (self.type == enum_value) {
var subtype = self.initSubtype(ufield.type);
if (subtype) |sb| {
return @unionInit(uefi.DevicePath, ufield.name, sb);
}
}
}
return null;
}
pub fn initSubtype(self: *const DevicePath, comptime TUnion: type) ?TUnion {
const type_info = @typeInfo(TUnion).Union;
const TTag = type_info.tag_type.?;
inline for (type_info.fields) |subtype| {
const tag_val: u8 = @intFromEnum(@field(TTag, subtype.name));
if (self.subtype == tag_val) {
return @unionInit(TUnion, subtype.name, @as(subtype.type, @ptrCast(self)));
}
}
return null;
}
};
comptime {
assert(4 == @sizeOf(DevicePath));
assert(1 == @alignOf(DevicePath));
assert(0 == @offsetOf(DevicePath, "type"));
assert(1 == @offsetOf(DevicePath, "subtype"));
assert(2 == @offsetOf(DevicePath, "length"));
}