zba-gdbstub/src/Packet.zig

236 lines
8.3 KiB
Zig

const std = @import("std");
const Allocator = std.mem.Allocator;
const Emulator = @import("lib.zig").Emulator;
const target = @import("Server.zig").target;
const memory_map = @import("Server.zig").memory_map;
const Self = @This();
const log = std.log.scoped(.Packet);
pub const max_len: usize = 0x1000;
contents: []const u8,
pub fn from(allocator: Allocator, str: []const u8) !Self {
var tokens = std.mem.tokenize(u8, str, "$#");
const contents = tokens.next() orelse return error.InvalidPacket;
const chksum_str = tokens.next() orelse return error.MissingCheckSum;
const chksum = std.fmt.parseInt(u8, chksum_str, 16) catch return error.InvalidChecksum;
// log.info("Contents: {s}", .{contents});
if (!Self.verify(contents, chksum)) return error.ChecksumMismatch;
return .{ .contents = try allocator.dupe(u8, contents) };
}
const String = union(enum) {
alloc: []const u8,
static: []const u8,
pub fn inner(self: *const @This()) []const u8 {
return switch (self.*) {
.static => |str| str,
.alloc => |str| str,
};
}
pub fn deinit(self: *@This(), allocator: Allocator) void {
switch (self.*) {
.alloc => |string| allocator.free(string),
.static => {},
}
self.* = undefined;
}
};
pub fn parse(self: *Self, allocator: Allocator, emu: Emulator) !String {
switch (self.contents[0]) {
// Required
'?' => {
const ret: Signal = .Trap;
// Deallocated by the caller
return .{ .alloc = try std.fmt.allocPrint(allocator, "T{x:0>2}thread:1;", .{@enumToInt(ret)}) };
},
'g' => {
const r = emu.registers();
const cpsr = emu.cpsr();
const reg_len = @sizeOf(u32) * 2; // Every byte is represented by 2 characters
const ret = try allocator.alloc(u8, r.len * reg_len + reg_len); // r0 -> r15 + CPSR
{
var i: u32 = 0;
while (i < r.len + 1) : (i += 1) {
const reg: u32 = @byteSwap(if (i < r.len) r[i] else cpsr); // Seems like GDB expects this
// bufPrintIntToSlice writes to the provided slice, which is all we want from this
// consequentially, we ignore the slice it returns since it just references the slice
// passed as an argument
_ = std.fmt.bufPrintIntToSlice(ret[i * 8 ..][0..8], reg, 16, .lower, .{ .fill = '0', .width = 8 });
}
}
return .{ .alloc = ret };
},
'G' => @panic("TODO: Register Write"),
'm' => {
// TODO: Actually reference GBA Memory
log.err("{s}", .{self.contents});
var tokens = std.mem.tokenize(u8, self.contents[1..], ",");
const addr_str = tokens.next() orelse return .{ .static = "E9999" }; // EUNKNOWN
const length_str = tokens.next() orelse return .{ .static = "E9999" }; // EUNKNOWN
const addr = try std.fmt.parseInt(u32, addr_str, 16);
const len = try std.fmt.parseInt(u32, length_str, 16);
const ret = try allocator.alloc(u8, len * 2);
{
var i: u32 = 0;
while (i < len) : (i += 1) {
const value: u8 = emu.read(addr + i);
_ = std.fmt.bufPrintIntToSlice(ret[i * 2 ..][0..2], value, 16, .lower, .{ .fill = '0', .width = 2 });
}
}
return .{ .alloc = ret };
},
'M' => @panic("TODO: Memory Write"),
'c' => @panic("TODO: Continue"),
's' => @panic("TODO: Step"),
// Optional
'H' => {
log.warn("{s}", .{self.contents});
switch (self.contents[1]) {
'g', 'c' => return .{ .static = "OK" },
else => {
log.warn("Unimplemented: {s}", .{self.contents});
return .{ .static = "" };
},
}
},
'v' => {
if (substr(self.contents[1..], "MustReplyEmpty")) {
return .{ .static = "" };
}
log.warn("Unimplemented: {s}", .{self.contents});
return .{ .static = "" };
},
'q' => {
if (self.contents[1] == 'C' and self.contents.len == 2) return .{ .static = "QC1" };
if (substr(self.contents[1..], "fThreadInfo")) return .{ .static = "m1" };
if (substr(self.contents[1..], "sThreadInfo")) return .{ .static = "l" };
if (substr(self.contents[1..], "Attached")) return .{ .static = "1" }; // Tell GDB we're attached to a process
if (substr(self.contents[1..], "Supported")) {
const format = "PacketSize={x:};qXfer:features:read+;qXfer:memory-map:read+";
// TODO: Anything else?
const ret = try std.fmt.allocPrint(allocator, format, .{Self.max_len});
return .{ .alloc = ret };
}
if (substr(self.contents[1..], "Xfer:features:read")) {
var tokens = std.mem.tokenize(u8, self.contents[1..], ":,");
_ = tokens.next(); // Xfer
_ = tokens.next(); // features
_ = tokens.next(); // read
const annex = tokens.next() orelse return .{ .static = "E00" };
const offset_str = tokens.next() orelse return .{ .static = "E00" };
const length_str = tokens.next() orelse return .{ .static = "E00" };
if (std.mem.eql(u8, annex, "target.xml")) {
log.info("Providing ARMv4T target description", .{});
const offset = try std.fmt.parseInt(usize, offset_str, 16);
const length = try std.fmt.parseInt(usize, length_str, 16);
// + 2 to account for the "m " in the response
// subtract offset so that the allocated buffer isn't
// larger than it needs to be TODO: Test this?
const len = @min(length, (target.len + 1) - offset);
const ret = try allocator.alloc(u8, len);
ret[0] = if (ret.len < length) 'l' else 'm';
std.mem.copy(u8, ret[1..], target[offset..]);
return .{ .alloc = ret };
} else {
log.err("Unexpected Annex: {s}", .{annex});
return .{ .static = "E00" };
}
return .{ .static = "" };
}
if (substr(self.contents[1..], "Xfer:memory-map:read")) {
var tokens = std.mem.tokenize(u8, self.contents[1..], ":,");
_ = tokens.next(); // Xfer
_ = tokens.next(); // memory-map
_ = tokens.next(); // read
const offset_str = tokens.next() orelse return .{ .static = "E9999" };
const length_str = tokens.next() orelse return .{ .static = "E9999" };
const offset = try std.fmt.parseInt(usize, offset_str, 16);
const length = try std.fmt.parseInt(usize, length_str, 16);
// see above
const len = @min(length, (memory_map.len + 1) - offset);
const ret = try allocator.alloc(u8, len);
ret[0] = if (ret.len < length) 'l' else 'm';
std.mem.copy(u8, ret[1..], memory_map[offset..]);
return .{ .alloc = ret };
}
log.warn("Unimplemented: {s}", .{self.contents});
return .{ .static = "" };
},
else => {
log.warn("Unknown: {s}", .{self.contents});
return .{ .static = "" };
},
}
}
fn substr(haystack: []const u8, needle: []const u8) bool {
return std.mem.indexOf(u8, haystack, needle) != null;
}
pub fn deinit(self: *Self, allocator: Allocator) void {
allocator.free(self.contents);
self.* = undefined;
}
pub fn checksum(input: []const u8) u8 {
var sum: usize = 0;
for (input) |char| sum += char;
return @truncate(u8, sum);
}
fn verify(input: []const u8, chksum: u8) bool {
return Self.checksum(input) == chksum;
}
const Signal = enum(u32) {
Hup, // Hangup
Int, // Interrupt
Quit, // Quit
Ill, // Illegal Instruction
Trap, // Trace/Breakponit trap
Abrt, // Aborted
};