launch

#!/usr/bin/env python3

import argparse
import atexit
import itertools
import os
import os.path
import pexpect
import random
import resource
import shlex
import shutil
import signal
import subprocess
import sys
import time

from contextlib import redirect_stdout


TMUX_CONF = './.tmux.conf'
MIN_PORT = 24000
MAX_PORT = 32000


def RandomPort():
    portlock = None
    ports = list(range(MIN_PORT, MAX_PORT))
    while not portlock and ports:
        port = random.choice(ports)
        ports.remove(port)
        portlock = f'/tmp/launch-port-{port}.lock'
        try:
            fd = os.open(portlock, os.O_CREAT | os.O_EXCL | os.O_CLOEXEC)
            os.close(fd)

            def unlock():
                try:
                    os.remove(portlock)
                except OSError:
                    pass

            atexit.register(unlock)
            return port
        except OSError:
            portlock = None
    raise RuntimeError('Run out of TCP port locks!')


CONFIG = {
    'board': 'malta',
    'config': {
        'debug': False,
        'gdbport': RandomPort(),
        'graphics': False,
        'network': False,
        'storage': '',
        'elf': 'sys/mimiker.elf',
        'initrd': 'initrd.cpio',
        'args': [],
        'board': {
            'malta': {
                'kernel': 'sys/mimiker.elf',
                'dts': None,
                'simulator': 'qemu'
            },
            'rpi3': {
                'kernel': 'sys/mimiker.img.gz',
                'dts': 'sys/dts/rpi3.dts',
                'initrd-start': 0x8000000,
                'simulator': 'qemu'
            },
            'litex-riscv': {
                'kernel': 'sys/mimiker.img',
                'dts': 'sys/dts/litex-riscv.dts',
                'initrd-start': 0x42000000,
                'simulator': 'renode',
            },
            'sifive_u': {
                'kernel': 'sys/mimiker.elf',
                'dts': 'sys/dts/sifive_u.dts',
                'initrd-start': 0xbf000000,
                'simulator': 'qemu'
            },
        },
    },
    'qemu': {
        'options': [
            '-nodefaults',
            # Configure record/replay function for deterministic replay,
            # refer to https://github.com/qemu/qemu/blob/master/docs/replay.txt
            # '-icount', 'shift=3,sleep=on,rr=record,rrfile=replay.bin',
            '-icount', 'shift=3,align=off,sleep=on',
            '-rtc', 'clock=vm',
            '-kernel', '{kernel}',
            '-initrd', '{initrd}',
            '-gdb', 'tcp:127.0.0.1:{gdbport},server,wait',
            '-serial', 'none'],
        'board': {
            'malta': {
                'binary': 'qemu-mimiker-mipsel',
                'options': [
                    '-device', 'usb-kbd',
                    '-device', 'usb-mouse',
                    '-device', 'VGA',
                    '-machine', 'malta',
                    '-cpu', 'P5600'],
                'network_options': [
                    '-device', 'rtl8139,netdev=net0',
                    '-netdev', 'user,id=net0,hostfwd=tcp::10022-:22',
                    '-object', 'filter-dump,id=net0,netdev=net0,file=rtl.pcap'
                ],
                'uarts': [
                    dict(name='/dev/tty0', port=RandomPort(), raw=True),
                    dict(name='/dev/tty1', port=RandomPort()),
                    dict(name='/dev/cons', port=RandomPort())
                ],
                'storage_options': [
                    '-device', 'usb-storage,drive=stick',
                ],
                'drive': 'if=none,id=stick,file={path}',
            },
            'rpi3': {
                'binary': 'qemu-mimiker-aarch64',
                'options': [
                    '-machine', 'raspi3b',
                    '-smp', '4',
                    '-cpu', 'cortex-a53'],
                'network_options': [],
                'uarts': [
                    dict(name='/dev/tty0', port=RandomPort(), raw=True)
                ],
                'storage_options': [],
                'drive': 'if=sd,index=0,format=qcow2,file={path}',
            },
            'sifive_u': {
                'binary': 'qemu-mimiker-riscv64',
                'options': [
                    '-machine', 'sifive_u',
                    '-smp', '5',
                    '-m', '1G',
                ],
                'network_options': [],
                'uarts': [
                    dict(name='/dev/tty0', port=RandomPort(), raw=True),
                    dict(name='/dev/tty1', port=RandomPort(), raw=True)
                ]
            },
        }
    },
    'renode': {
        'options': {
            '--console',
        },
        'board': {
            'litex-riscv': {
                'script': 'litex_vexriscv_mimiker.resc',
                'uarts': [
                    dict(name='/dev/tty0', port=RandomPort(), raw=True)
                ]
            }
        }
    },
    'gdb': {
        'pre-options': [
            '-n',
            '-ex=set confirm no',
            '-iex=set auto-load safe-path {}/'.format(os.getcwd()),
            '-ex=set tcp connect-timeout 30',
            '-ex=target extended-remote localhost:{gdbport}',
            '--silent',
        ],
        'extra-options': [],
        'post-options': [
            '-ex=source .gdbinit',
            '-ex=continue',
        ],
        'board': {
            'malta': {
                'binary': 'mipsel-mimiker-elf-gdb'
            },
            'rpi3': {
                'binary': 'aarch64-mimiker-elf-gdb'
            },
            'litex-riscv': {
                'binary': 'riscv32-mimiker-elf-gdb'
            },
            'sifive_u': {
                'binary': 'riscv64-mimiker-elf-gdb',
                'extra-options': [
                    '-ex=add-inferior',
                    '-ex=inferior 2',
                    '-ex=file {kernel}',
                    '-ex=attach 2',
                    '-ex=set schedule-multiple on',
                ],
            },
        }
    }
}


def setboard(name):
    setvar('board', name)
    # go over top-level configuration variables
    for top, config in CONFIG.items():
        if type(config) is not dict:
            continue
        board = getvar('board.' + name, start=config, failok=True)
        if not board:
            continue
        # merge board variables into generic set
        for key, value in board.items():
            if key not in config:
                config[key] = value
            elif type(value) == list:
                config[key].extend(value)
            else:
                raise RuntimeError(f'Cannot merge {top}.board.{name}.{key} '
                                   f'into {top}')
        # finish merging by removing alternative configurations
        del config['board']


def getvar(name, start=CONFIG, failok=False):
    value = start
    for f in name.split('.'):
        try:
            value = value[f]
        except KeyError as ex:
            if failok:
                return None
            raise ex
    return value


def setvar(name, val, config=CONFIG):
    fs = name.split('.')
    while len(fs) > 1:
        config = config[fs.pop(0)]
    config[fs.pop(0)] = val


def getopts(*names):
    opts = itertools.chain.from_iterable([getvar(name) for name in names])
    return [opt.format(**getvar('config')) for opt in opts]


class Launchable():
    def __init__(self, name, cmd):
        self.name = name
        self.cmd = cmd
        self.window = None
        self.pid = None
        self.options = []

    def start(self, session):
        cmd = ' '.join([self.cmd] + list(map(shlex.quote, self.options)))
        self.window = session.new_window(
            attach=False, window_name=self.name, window_shell=cmd)
        self.pid = int(self.window.attached_pane._info['pane_pid'])

    def spawn(self, dimensions=None, cpulimit=None):
        def set_cpu_limit():
            if cpulimit is None:
                return
            soft, hard = resource.getrlimit(resource.RLIMIT_CPU)
            if soft >= 0:
                soft = min(soft, cpulimit)
            elif hard >= 0:
                soft = min(hard, cpulimit)
            else:
                soft = cpulimit
            resource.setrlimit(resource.RLIMIT_CPU, (soft, hard))

        return pexpect.spawn(self.cmd, self.options, dimensions=dimensions,
                             preexec_fn=set_cpu_limit)

    def stop(self):
        if self.pid is None:
            return

        time.sleep(0.2)
        try:
            os.kill(self.pid, signal.SIGKILL)
        except ProcessLookupError:
            # Process has already quit!
            pass
        self.pid = None


class QEMU(Launchable):
    def __init__(self):
        super().__init__('qemu', getvar('qemu.binary'))

        self.options = getopts('qemu.options')
        for uart in getvar('qemu.uarts'):
            port = uart['port']
            self.options += ['-serial', f'tcp:127.0.0.1:{port},server,wait']

        if not getvar('config.dts'):
            if getvar('config.args'):
                self.options += ['-append', ' '.join(getvar('config.args'))]
        else:
            self.options += ['-dtb', 'launch.dtb']

        if getvar('config.debug'):
            self.options += ['-S']
        if not getvar('config.graphics'):
            self.options += ['-display', 'none']
        if getvar('config.network'):
            self.options += getopts('qemu.network_options')

        storage = getvar('config.storage')
        if storage:
            if not os.path.isfile(storage):
                raise SystemExit(f'{storage}: file does not exist!')
            drive = getvar('qemu.drive', failok=True)
            if not drive:
                raise SystemExit('Default drive is not defined for the '
                                 'selected platform.')
            self.options += ['-drive', drive.format(path=storage)]
            self.options += getopts('qemu.storage_options')


class RENODE(Launchable):
    def __init__(self):
        super().__init__('renode', 'renode')

        self.options = getopts('renode.options')

        script = getvar('renode.script', failok=False)
        self.options += [f'-e include @scripts/single-node/{script}']

        for i, uart in enumerate(getvar('renode.uarts')):
            port = uart['port']
            dev = f'uart{i}'
            self.options += ['-e emulation CreateServerSocketTerminal ' +
                             f'{port} "{dev}" False']
            self.options += [f'-e connector Connect sysbus.{dev} {dev}']

        if getvar('config.debug'):
            gdbport = getvar('config.gdbport', failok=False)
            self.options += [f'-e machine StartGdbServer {gdbport}']

        self.options += ['-e start']


class GDB(Launchable):
    def __init__(self):
        super().__init__('gdb', getvar('gdb.binary'))

        self.options += getopts(
                'gdb.pre-options', 'gdb.extra-options', 'gdb.post-options')

        if getvar('board') != 'sifive_u':
            self.options.append(getvar('config.elf'))


class SOCAT(Launchable):
    def __init__(self, name, tcp_port, raw=False):
        super().__init__(name, 'socat')
        # The simulator will only open the server after some time has
        # passed.  To minimize the delay, keep reconnecting until success.
        stdio_opt = 'STDIO'
        if raw:
            stdio_opt += ',cfmakeraw'
        self.options = [stdio_opt, f'tcp:localhost:{tcp_port},retry,forever']


def PostMortem(gdb):
    gdb.sendline('post-mortem')
    gdb.expect_exact('(gdb) ')
    print(gdb.before.decode())
    if sys.stdin.isatty():
        print('(gdb) ', end='')
        gdb.interact()
    gdb.sendline('kill')
    gdb.sendline('quit')


def TestRun(sim, dbg, timeout):
    sim_proc = sim.spawn(cpulimit=timeout)
    gdb_proc = dbg.spawn(dimensions=(int(os.environ['LINES']),
                                     int(os.environ['COLUMNS'])))

    try:
        # No need to wait for the simulator, GDB will terminate it!
        rc = gdb_proc.expect_exact([pexpect.EOF, '(gdb) '], timeout=None)

        if rc == 1:
            timed_out = b'Program received signal SIGINT' in gdb_proc.before
            print('\n*** GDB OUTPUT ***\n\n')
            print(gdb_proc.before.decode('utf-8'))
            PostMortem(gdb_proc)
            print('Test run %s!' % ('timeout' if timed_out else 'failed'))
            if timed_out:
                rc = 2
    except KeyboardInterrupt:
        print('Test run was interrupted!')
        signal.signal(signal.SIGINT, signal.SIG_IGN)
        gdb_proc.terminate()
        sim_proc.terminate()
        rc = 3
    sys.exit(rc)


def DevelRun(sim, dbg):
    from libtmux import Server, Session

    subprocess.run(['tmux', '-f', TMUX_CONF, '-L', 'mimiker', 'start-server'])

    server = Server(config_file=TMUX_CONF, socket_name='mimiker')

    if server.has_session('mimiker'):
        server.kill_session('mimiker')

    session = server.new_session(session_name='mimiker', attach=False,
                                 window_name=':0', window_command='sleep 1')

    uarts = [SOCAT(uart['name'], uart['port'], uart.get('raw', False))
             for uart in getvar(f'{sim.name}.uarts')]

    try:
        sim.start(session)
        for uart in uarts:
            uart.start(session)
        if dbg:
            dbg.start(session)

        session.kill_window(':0')
        session.select_window(dbg.name if dbg else '/dev/tty0')
        session.attach_session()
    finally:
        server.kill_server()

        # Give the simulator a chance to exit gracefully
        sim.stop()


def setup_terminal():
    cols, rows = shutil.get_terminal_size(fallback=(132, 43))

    os.environ['COLUMNS'] = str(cols)
    os.environ['LINES'] = str(rows)

    if sys.stdin.isatty():
        subprocess.run(['stty', 'cols', str(cols), 'rows', str(rows)])


def prepare_dtb():
    bootargs = ' '.join(getvar('config.args'))
    dts = getvar('config.dts')
    if not dts:
        return

    if not os.path.isfile(dts):
        raise SystemExit(f'{dts}: file does not exist!')

    initrd_start = getvar('config.initrd-start')
    initrd_end = initrd_start + os.path.getsize(getvar('config.initrd'))

    try:
        with open('launch.dts', mode='w') as tmp:
            with redirect_stdout(tmp):
                print(f'/include/ "{dts}"')
                print('&{/chosen} {')
                print(f'    bootargs = "{bootargs}";')
                print(f'    linux,initrd-start = <{initrd_start}>;')
                print(f'    linux,initrd-end = <{initrd_end}>;')
                print('};')

        subprocess.check_call(
            f'dtc -O dtb -o launch.dtb {tmp.name}', shell=True)
    finally:
        try:
            os.remove('launch.dts')
        except OSError:
            pass


if __name__ == '__main__':
    setup_terminal()

    parser = argparse.ArgumentParser(
        description='Launch kernel in a board simulator.')
    parser.add_argument('args', metavar='ARGS', type=str,
                        nargs=argparse.REMAINDER, help='Kernel arguments.')
    parser.add_argument('-d', '--debug', action='store_true',
                        help='Start debugging session with gdb.')
    parser.add_argument('-n', '--network', action='store_true',
                        help='Append qemu network configuration (if any).')
    parser.add_argument('-t', '--test-run', action='store_true',
                        help='Test-run mode: simulator output goes to stdout.')
    parser.add_argument('-T', '--timeout', type=int, default=60,
                        help='Test-run will fail after n seconds.')
    parser.add_argument('-g', '--graphics', action='store_true',
                        help='Enable VGA output.')
    parser.add_argument('-b', '--board', default='rpi3',
                        choices=['malta', 'rpi3', 'litex-riscv', 'sifive_u'],
                        help='Emulated board.')
    parser.add_argument('-s', '--storage', type=str,
                        help='QCOW2 image to be attached as a default storage '
                             'device for given platform.')
    args = parser.parse_args()

    # Used by tmux to override ./.tmux.conf with ./.tmux.conf.local
    os.environ['MIMIKER_REPO'] = os.path.dirname(os.path.realpath(sys.argv[0]))

    setboard(args.board)
    setvar('config.debug', args.debug)
    setvar('config.graphics', args.graphics)
    setvar('config.args', args.args)
    setvar('config.network', args.network)
    setvar('config.storage', args.storage)

    # Check if the kernel file is available
    if not os.path.isfile(getvar('config.kernel')):
        raise SystemExit('%s: file does not exist!' % getvar('config.kernel'))

    prepare_dtb()

    sim_name = getvar('config.simulator', failok=False)

    # Create simulator launcher
    if args.test_run:
        setvar(f'{sim_name}.uarts', [])

    sim = QEMU() if sim_name == 'qemu' else RENODE()

    # Create debugger launcher
    if args.debug:
        kernel_args = {}
        for arg in args.args:
            try:
                key, val = arg.split('=', 1)
                kernel_args[key] = val
            except ValueError:
                pass

        if 'test' in kernel_args:
            host_path = "sysroot/bin/utest.dbg"
        elif 'init' in kernel_args:
            host_path = f"sysroot{kernel_args['init']}.dbg"
        else:
            host_path = None

        if host_path is not None:
            extra = getvar('gdb.extra-options')
            extra.append(f'-ex=add-symbol-file {host_path} 0x400000')

        dbg = GDB()
    elif args.test_run:
        setvar('gdb.post-options', ['-ex=source .gdbinit-test'])
        dbg = GDB()
    else:
        dbg = None

    if args.test_run:
        TestRun(sim, dbg, args.timeout)
    else:
        DevelRun(sim, dbg)