fuzz_runner

var fuzz_runner: if (builtin.fuzz) struct

File

Code

var fuzz_runner: if (builtin.fuzz) struct {
    indexes: []u32,
    server: *std.zig.Server,
    gpa: std.mem.Allocator,
    io: Io,
    input_poller: Io.Future(Io.Cancelable!void),

    comptime {
        assert(builtin.fuzz); // `fuzz_runner` was analyzed in non-fuzzing compilation
    }

    export fn runner_test_run(i: u32) void {
        @disableInstrumentation();

        fuzz_runner.server.serveU32Message(.fuzz_test_change, i) catch |e| switch (e) {
            error.WriteFailed => panic("failed to write to stdout: {t}", .{stdout_writer.err.?}),
        };

        testing.allocator_instance = .init(std.heap.page_allocator, .{
            .canary = 0xc3a701ba,
            .check_write_after_free = true,
        });
        defer if (testing.allocator_instance.deinit() != 0) std.process.exit(1);
        is_fuzz_test = false;

        builtin.test_functions[fuzz_runner.indexes[i]].func() catch |err| switch (err) {
            error.SkipZigTest => return,
            else => {
                if (@errorReturnTrace()) |trace| {
                    std.debug.dumpErrorReturnTrace(trace);
                }
                std.debug.print("failed with error.{t}\n", .{err});
                std.process.exit(1);
            },
        };

        if (!is_fuzz_test) @panic("missed call to std.testing.fuzz");
        if (log_err_count != 0) @panic("error logs detected");
    }

    export fn runner_test_name(i: u32) fuzz_abi.Slice {
        @disableInstrumentation();
        return .fromSlice(builtin.test_functions[fuzz_runner.indexes[i]].name);
    }

    export fn runner_broadcast_input(test_i: u32, bytes_slice: fuzz_abi.Slice) void {
        @disableInstrumentation();
        const bytes = bytes_slice.toSlice();
        fuzz_runner.server.serveBroadcastFuzzInputMessage(test_i, bytes) catch |e| switch (e) {
            error.WriteFailed => panic("failed to write to stdout: {t}", .{stdout_writer.err.?}),
        };
    }

    export fn runner_start_input_poller() void {
        @disableInstrumentation();
        const future = fuzz_runner.io.concurrent(inputPoller, .{}) catch |e| switch (e) {
            error.ConcurrencyUnavailable => @panic("failed to spawn concurrent fuzz input poller"),
        };
        fuzz_runner.input_poller = future;
    }

    export fn runner_stop_input_poller() void {
        @disableInstrumentation();
        assert(fuzz_runner.input_poller.cancel(fuzz_runner.io) == error.Canceled);
    }

    export fn runner_futex_wait(ptr: *const u32, expected: u32) bool {
        @disableInstrumentation();
        return fuzz_runner.io.futexWait(u32, ptr, expected) == error.Canceled;
    }

    export fn runner_futex_wake(ptr: *const u32, waiters: u32) void {
        @disableInstrumentation();
        fuzz_runner.io.futexWake(u32, ptr, waiters);
    }

    fn inputPoller() Io.Cancelable!void {
        @disableInstrumentation();
        switch (inputPollerInner()) {
            error.Canceled => |e| return e,
            error.ReadFailed => {
                if (stdin_reader.err.? == error.Canceled) return error.Canceled;
                panic("failed to read from stdin: {t}", .{stdin_reader.err.?});
            },
            error.EndOfStream => @panic("unexpected end of stdin"),
        }
    }

    fn inputPollerInner() (Io.Cancelable || Io.Reader.Error) {
        @disableInstrumentation();
        const server = fuzz_runner.server;
        var large_bytes_list: std.ArrayList(u8) = .empty;
        defer large_bytes_list.deinit(fuzz_runner.gpa);
        while (true) {
            const hdr = try server.receiveMessage();
            if (hdr.tag != .new_fuzz_input) {
                panic("unexpected message: {x}\n", .{@backingInt(hdr.tag)});
            }
            const test_i = try server.receiveBody_u32();
            const input_len = hdr.bytes_len - 4;
            const bytes = if (input_len <= server.in.buffer.len)
                try server.in.take(input_len)
            else bytes: {
                large_bytes_list.resize(fuzz_runner.gpa, @intCast(input_len)) catch @panic("OOM");
                try server.in.readSliceAll(large_bytes_list.items);
                break :bytes large_bytes_list.items;
            };
            if (fuzz_abi.fuzzer_receive_input(test_i, .fromSlice(bytes))) {
                return error.Canceled;
            }
        }
    }
} else void = undefined