lldbgdbserverutils.py 37.1 KB
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958
"""Module for supporting unit testing of the lldb-server debug monitor exe.
"""

from __future__ import division, print_function


import os
import os.path
import platform
import re
import six
import socket_packet_pump
import subprocess
from lldbsuite.test.lldbtest import *
from lldbsuite.test import configuration

from six.moves import queue


def _get_debug_monitor_from_lldb(lldb_exe, debug_monitor_basename):
    """Return the debug monitor exe path given the lldb exe path.

    This method attempts to construct a valid debug monitor exe name
    from a given lldb exe name.  It will return None if the synthesized
    debug monitor name is not found to exist.

    The debug monitor exe path is synthesized by taking the directory
    of the lldb exe, and replacing the portion of the base name that
    matches "lldb" (case insensitive) and replacing with the value of
    debug_monitor_basename.

    Args:
        lldb_exe: the path to an lldb executable.

        debug_monitor_basename: the base name portion of the debug monitor
            that will replace 'lldb'.

    Returns:
        A path to the debug monitor exe if it is found to exist; otherwise,
        returns None.

    """
    if not lldb_exe:
        return None

    exe_dir = os.path.dirname(lldb_exe)
    exe_base = os.path.basename(lldb_exe)

    # we'll rebuild the filename by replacing lldb with
    # the debug monitor basename, keeping any prefix or suffix in place.
    regex = re.compile(r"lldb", re.IGNORECASE)
    new_base = regex.sub(debug_monitor_basename, exe_base)

    debug_monitor_exe = os.path.join(exe_dir, new_base)
    if os.path.exists(debug_monitor_exe):
        return debug_monitor_exe

    new_base = regex.sub(
        'LLDB.framework/Versions/A/Resources/' +
        debug_monitor_basename,
        exe_base)
    debug_monitor_exe = os.path.join(exe_dir, new_base)
    if os.path.exists(debug_monitor_exe):
        return debug_monitor_exe

    return None


def get_lldb_server_exe():
    """Return the lldb-server exe path.

    Returns:
        A path to the lldb-server exe if it is found to exist; otherwise,
        returns None.
    """
    if "LLDB_DEBUGSERVER_PATH" in os.environ:
        return os.environ["LLDB_DEBUGSERVER_PATH"]

    return _get_debug_monitor_from_lldb(
        lldbtest_config.lldbExec, "lldb-server")


def get_debugserver_exe():
    """Return the debugserver exe path.

    Returns:
        A path to the debugserver exe if it is found to exist; otherwise,
        returns None.
    """
    if "LLDB_DEBUGSERVER_PATH" in os.environ:
        return os.environ["LLDB_DEBUGSERVER_PATH"]

    if configuration.arch and configuration.arch == "x86_64" and \
       platform.machine().startswith("arm64"):
        return '/Library/Apple/usr/libexec/oah/debugserver'

    return _get_debug_monitor_from_lldb(
        lldbtest_config.lldbExec, "debugserver")

_LOG_LINE_REGEX = re.compile(r'^(lldb-server|debugserver)\s+<\s*(\d+)>' +
                             '\s+(read|send)\s+packet:\s+(.+)$')


def _is_packet_lldb_gdbserver_input(packet_type, llgs_input_is_read):
    """Return whether a given packet is input for lldb-gdbserver.

    Args:
        packet_type: a string indicating 'send' or 'receive', from a
            gdbremote packet protocol log.

        llgs_input_is_read: true if lldb-gdbserver input (content sent to
            lldb-gdbserver) is listed as 'read' or 'send' in the packet
            log entry.

    Returns:
        True if the packet should be considered input for lldb-gdbserver; False
        otherwise.
    """
    if packet_type == 'read':
        # when llgs is the read side, then a read packet is meant for
        # input to llgs (when captured from the llgs/debugserver exe).
        return llgs_input_is_read
    elif packet_type == 'send':
        # when llgs is the send side, then a send packet is meant to
        # be input to llgs (when captured from the lldb exe).
        return not llgs_input_is_read
    else:
        # don't understand what type of packet this is
        raise "Unknown packet type: {}".format(packet_type)


def handle_O_packet(context, packet_contents, logger):
    """Handle O packets."""
    if (not packet_contents) or (len(packet_contents) < 1):
        return False
    elif packet_contents[0] != "O":
        return False
    elif packet_contents == "OK":
        return False

    new_text = gdbremote_hex_decode_string(packet_contents[1:])
    context["O_content"] += new_text
    context["O_count"] += 1

    if logger:
        logger.debug(
            "text: new \"{}\", cumulative: \"{}\"".format(
                new_text, context["O_content"]))

    return True

_STRIP_CHECKSUM_REGEX = re.compile(r'#[0-9a-fA-F]{2}$')
_STRIP_COMMAND_PREFIX_REGEX = re.compile(r"^\$")
_STRIP_COMMAND_PREFIX_M_REGEX = re.compile(r"^\$m")


def assert_packets_equal(asserter, actual_packet, expected_packet):
    # strip off the checksum digits of the packet.  When we're in
    # no-ack mode, the # checksum is ignored, and should not be cause
    # for a mismatched packet.
    actual_stripped = _STRIP_CHECKSUM_REGEX.sub('', actual_packet)
    expected_stripped = _STRIP_CHECKSUM_REGEX.sub('', expected_packet)
    asserter.assertEqual(actual_stripped, expected_stripped)


def expect_lldb_gdbserver_replay(
        asserter,
        sock,
        test_sequence,
        pump_queues,
        timeout_seconds,
        logger=None):
    """Replay socket communication with lldb-gdbserver and verify responses.

    Args:
        asserter: the object providing assertEqual(first, second, msg=None), e.g. TestCase instance.

        sock: the TCP socket connected to the lldb-gdbserver exe.

        test_sequence: a GdbRemoteTestSequence instance that describes
            the messages sent to the gdb remote and the responses
            expected from it.

        timeout_seconds: any response taking more than this number of
           seconds will cause an exception to be raised.

        logger: a Python logger instance.

    Returns:
        The context dictionary from running the given gdbremote
        protocol sequence.  This will contain any of the capture
        elements specified to any GdbRemoteEntry instances in
        test_sequence.

        The context will also contain an entry, context["O_content"]
        which contains the text from the inferior received via $O
        packets.  $O packets should not attempt to be matched
        directly since they are not entirely deterministic as to
        how many arrive and how much text is in each one.

        context["O_count"] will contain an integer of the number of
        O packets received.
    """

    # Ensure we have some work to do.
    if len(test_sequence.entries) < 1:
        return {}

    context = {"O_count": 0, "O_content": ""}
    with socket_packet_pump.SocketPacketPump(sock, pump_queues, logger) as pump:
        # Grab the first sequence entry.
        sequence_entry = test_sequence.entries.pop(0)

        # While we have an active sequence entry, send messages
        # destined for the stub and collect/match/process responses
        # expected from the stub.
        while sequence_entry:
            if sequence_entry.is_send_to_remote():
                # This is an entry to send to the remote debug monitor.
                send_packet = sequence_entry.get_send_packet()
                if logger:
                    if len(send_packet) == 1 and send_packet[0] == chr(3):
                        packet_desc = "^C"
                    else:
                        packet_desc = send_packet
                    logger.info(
                        "sending packet to remote: {}".format(packet_desc))
                sock.sendall(send_packet.encode())
            else:
                # This is an entry expecting to receive content from the remote
                # debug monitor.

                # We'll pull from (and wait on) the queue appropriate for the type of matcher.
                # We keep separate queues for process output (coming from non-deterministic
                # $O packet division) and for all other packets.
                if sequence_entry.is_output_matcher():
                    try:
                        # Grab next entry from the output queue.
                        content = pump_queues.output_queue().get(True, timeout_seconds)
                    except queue.Empty:
                        if logger:
                            logger.warning(
                                "timeout waiting for stub output (accumulated output:{})".format(
                                    pump.get_accumulated_output()))
                        raise Exception(
                            "timed out while waiting for output match (accumulated output: {})".format(
                                pump.get_accumulated_output()))
                else:
                    try:
                        content = pump_queues.packet_queue().get(True, timeout_seconds)
                    except queue.Empty:
                        if logger:
                            logger.warning(
                                "timeout waiting for packet match (receive buffer: {})".format(
                                    pump.get_receive_buffer()))
                        raise Exception(
                            "timed out while waiting for packet match (receive buffer: {})".format(
                                pump.get_receive_buffer()))

                # Give the sequence entry the opportunity to match the content.
                # Output matchers might match or pass after more output accumulates.
                # Other packet types generally must match.
                asserter.assertIsNotNone(content)
                context = sequence_entry.assert_match(
                    asserter, content, context=context)

            # Move on to next sequence entry as needed.  Some sequence entries support executing multiple
            # times in different states (for looping over query/response
            # packets).
            if sequence_entry.is_consumed():
                if len(test_sequence.entries) > 0:
                    sequence_entry = test_sequence.entries.pop(0)
                else:
                    sequence_entry = None

        # Fill in the O_content entries.
        context["O_count"] = 1
        context["O_content"] = pump.get_accumulated_output()

    return context


def gdbremote_hex_encode_string(str):
    output = ''
    for c in str:
        output += '{0:02x}'.format(ord(c))
    return output


def gdbremote_hex_decode_string(str):
    return str.decode("hex")


def gdbremote_packet_encode_string(str):
    checksum = 0
    for c in str:
        checksum += ord(c)
    return '$' + str + '#{0:02x}'.format(checksum % 256)


def build_gdbremote_A_packet(args_list):
    """Given a list of args, create a properly-formed $A packet containing each arg.
    """
    payload = "A"

    # build the arg content
    arg_index = 0
    for arg in args_list:
        # Comma-separate the args.
        if arg_index > 0:
            payload += ','

        # Hex-encode the arg.
        hex_arg = gdbremote_hex_encode_string(arg)

        # Build the A entry.
        payload += "{},{},{}".format(len(hex_arg), arg_index, hex_arg)

        # Next arg index, please.
        arg_index += 1

    # return the packetized payload
    return gdbremote_packet_encode_string(payload)


def parse_reg_info_response(response_packet):
    if not response_packet:
        raise Exception("response_packet cannot be None")

    # Strip off prefix $ and suffix #xx if present.
    response_packet = _STRIP_COMMAND_PREFIX_REGEX.sub("", response_packet)
    response_packet = _STRIP_CHECKSUM_REGEX.sub("", response_packet)

    # Build keyval pairs
    values = {}
    for kv in response_packet.split(";"):
        if len(kv) < 1:
            continue
        (key, val) = kv.split(':')
        values[key] = val

    return values


def parse_threadinfo_response(response_packet):
    if not response_packet:
        raise Exception("response_packet cannot be None")

    # Strip off prefix $ and suffix #xx if present.
    response_packet = _STRIP_COMMAND_PREFIX_M_REGEX.sub("", response_packet)
    response_packet = _STRIP_CHECKSUM_REGEX.sub("", response_packet)

    # Return list of thread ids
    return [int(thread_id_hex, 16) for thread_id_hex in response_packet.split(
        ",") if len(thread_id_hex) > 0]


def unpack_endian_binary_string(endian, value_string):
    """Unpack a gdb-remote binary (post-unescaped, i.e. not escaped) response to an unsigned int given endianness of the inferior."""
    if not endian:
        raise Exception("endian cannot be None")
    if not value_string or len(value_string) < 1:
        raise Exception("value_string cannot be None or empty")

    if endian == 'little':
        value = 0
        i = 0
        while len(value_string) > 0:
            value += (ord(value_string[0]) << i)
            value_string = value_string[1:]
            i += 8
        return value
    elif endian == 'big':
        value = 0
        while len(value_string) > 0:
            value = (value << 8) + ord(value_string[0])
            value_string = value_string[1:]
        return value
    else:
        # pdp is valid but need to add parse code once needed.
        raise Exception("unsupported endian:{}".format(endian))


def unpack_register_hex_unsigned(endian, value_string):
    """Unpack a gdb-remote $p-style response to an unsigned int given endianness of inferior."""
    if not endian:
        raise Exception("endian cannot be None")
    if not value_string or len(value_string) < 1:
        raise Exception("value_string cannot be None or empty")

    if endian == 'little':
        value = 0
        i = 0
        while len(value_string) > 0:
            value += (int(value_string[0:2], 16) << i)
            value_string = value_string[2:]
            i += 8
        return value
    elif endian == 'big':
        return int(value_string, 16)
    else:
        # pdp is valid but need to add parse code once needed.
        raise Exception("unsupported endian:{}".format(endian))


def pack_register_hex(endian, value, byte_size=None):
    """Unpack a gdb-remote $p-style response to an unsigned int given endianness of inferior."""
    if not endian:
        raise Exception("endian cannot be None")

    if endian == 'little':
        # Create the litt-endian return value.
        retval = ""
        while value != 0:
            retval = retval + "{:02x}".format(value & 0xff)
            value = value >> 8
        if byte_size:
            # Add zero-fill to the right/end (MSB side) of the value.
            retval += "00" * (byte_size - len(retval) // 2)
        return retval

    elif endian == 'big':
        retval = ""
        while value != 0:
            retval = "{:02x}".format(value & 0xff) + retval
            value = value >> 8
        if byte_size:
            # Add zero-fill to the left/front (MSB side) of the value.
            retval = ("00" * (byte_size - len(retval) // 2)) + retval
        return retval

    else:
        # pdp is valid but need to add parse code once needed.
        raise Exception("unsupported endian:{}".format(endian))


class GdbRemoteEntryBase(object):

    def is_output_matcher(self):
        return False


class GdbRemoteEntry(GdbRemoteEntryBase):

    def __init__(
            self,
            is_send_to_remote=True,
            exact_payload=None,
            regex=None,
            capture=None,
            expect_captures=None):
        """Create an entry representing one piece of the I/O to/from a gdb remote debug monitor.

        Args:

            is_send_to_remote: True if this entry is a message to be
                sent to the gdbremote debug monitor; False if this
                entry represents text to be matched against the reply
                from the gdbremote debug monitor.

            exact_payload: if not None, then this packet is an exact
                send (when sending to the remote) or an exact match of
                the response from the gdbremote. The checksums are
                ignored on exact match requests since negotiation of
                no-ack makes the checksum content essentially
                undefined.

            regex: currently only valid for receives from gdbremote.
                When specified (and only if exact_payload is None),
                indicates the gdbremote response must match the given
                regex. Match groups in the regex can be used for two
                different purposes: saving the match (see capture
                arg), or validating that a match group matches a
                previously established value (see expect_captures). It
                is perfectly valid to have just a regex arg and to
                specify neither capture or expect_captures args. This
                arg only makes sense if exact_payload is not
                specified.

            capture: if specified, is a dictionary of regex match
                group indices (should start with 1) to variable names
                that will store the capture group indicated by the
                index. For example, {1:"thread_id"} will store capture
                group 1's content in the context dictionary where
                "thread_id" is the key and the match group value is
                the value. The value stored off can be used later in a
                expect_captures expression. This arg only makes sense
                when regex is specified.

            expect_captures: if specified, is a dictionary of regex
                match group indices (should start with 1) to variable
                names, where the match group should match the value
                existing in the context at the given variable name.
                For example, {2:"thread_id"} indicates that the second
                match group must match the value stored under the
                context's previously stored "thread_id" key. This arg
                only makes sense when regex is specified.
        """
        self._is_send_to_remote = is_send_to_remote
        self.exact_payload = exact_payload
        self.regex = regex
        self.capture = capture
        self.expect_captures = expect_captures

    def is_send_to_remote(self):
        return self._is_send_to_remote

    def is_consumed(self):
        # For now, all packets are consumed after first use.
        return True

    def get_send_packet(self):
        if not self.is_send_to_remote():
            raise Exception(
                "get_send_packet() called on GdbRemoteEntry that is not a send-to-remote packet")
        if not self.exact_payload:
            raise Exception(
                "get_send_packet() called on GdbRemoteEntry but it doesn't have an exact payload")
        return self.exact_payload

    def _assert_exact_payload_match(self, asserter, actual_packet):
        assert_packets_equal(asserter, actual_packet, self.exact_payload)
        return None

    def _assert_regex_match(self, asserter, actual_packet, context):
        # Ensure the actual packet matches from the start of the actual packet.
        match = self.regex.match(actual_packet)
        if not match:
            asserter.fail(
                "regex '{}' failed to match against content '{}'".format(
                    self.regex.pattern, actual_packet))

        if self.capture:
            # Handle captures.
            for group_index, var_name in list(self.capture.items()):
                capture_text = match.group(group_index)
                # It is okay for capture text to be None - which it will be if it is a group that can match nothing.
                # The user must be okay with it since the regex itself matched
                # above.
                context[var_name] = capture_text

        if self.expect_captures:
            # Handle comparing matched groups to context dictionary entries.
            for group_index, var_name in list(self.expect_captures.items()):
                capture_text = match.group(group_index)
                if not capture_text:
                    raise Exception(
                        "No content to expect for group index {}".format(group_index))
                asserter.assertEqual(capture_text, context[var_name])

        return context

    def assert_match(self, asserter, actual_packet, context=None):
        # This only makes sense for matching lines coming from the
        # remote debug monitor.
        if self.is_send_to_remote():
            raise Exception(
                "Attempted to match a packet being sent to the remote debug monitor, doesn't make sense.")

        # Create a new context if needed.
        if not context:
            context = {}

        # If this is an exact payload, ensure they match exactly,
        # ignoring the packet checksum which is optional for no-ack
        # mode.
        if self.exact_payload:
            self._assert_exact_payload_match(asserter, actual_packet)
            return context
        elif self.regex:
            return self._assert_regex_match(asserter, actual_packet, context)
        else:
            raise Exception(
                "Don't know how to match a remote-sent packet when exact_payload isn't specified.")


class MultiResponseGdbRemoteEntry(GdbRemoteEntryBase):
    """Represents a query/response style packet.

    Assumes the first item is sent to the gdb remote.
    An end sequence regex indicates the end of the query/response
    packet sequence.  All responses up through (but not including) the
    end response are stored in a context variable.

    Settings accepted from params:

        next_query or query: required.  The typical query packet without the $ prefix or #xx suffix.
            If there is a special first packet to start the iteration query, see the
            first_query key.

        first_query: optional. If the first query requires a special query command, specify
            it with this key.  Do not specify the $ prefix or #xx suffix.

        append_iteration_suffix: defaults to False.  Specify True if the 0-based iteration
            index should be appended as a suffix to the command.  e.g. qRegisterInfo with
            this key set true will generate query packets of qRegisterInfo0, qRegisterInfo1,
            etc.

        end_regex: required. Specifies a compiled regex object that will match the full text
            of any response that signals an end to the iteration.  It must include the
            initial $ and ending #xx and must match the whole packet.

        save_key: required.  Specifies the key within the context where an array will be stored.
            Each packet received from the gdb remote that does not match the end_regex will get
            appended to the array stored within the context at that key.

        runaway_response_count: optional. Defaults to 10000. If this many responses are retrieved,
            assume there is something wrong with either the response collection or the ending
            detection regex and throw an exception.
    """

    def __init__(self, params):
        self._next_query = params.get("next_query", params.get("query"))
        if not self._next_query:
            raise "either next_query or query key must be specified for MultiResponseGdbRemoteEntry"

        self._first_query = params.get("first_query", self._next_query)
        self._append_iteration_suffix = params.get(
            "append_iteration_suffix", False)
        self._iteration = 0
        self._end_regex = params["end_regex"]
        self._save_key = params["save_key"]
        self._runaway_response_count = params.get(
            "runaway_response_count", 10000)
        self._is_send_to_remote = True
        self._end_matched = False

    def is_send_to_remote(self):
        return self._is_send_to_remote

    def get_send_packet(self):
        if not self.is_send_to_remote():
            raise Exception(
                "get_send_packet() called on MultiResponseGdbRemoteEntry that is not in the send state")
        if self._end_matched:
            raise Exception(
                "get_send_packet() called on MultiResponseGdbRemoteEntry but end of query/response sequence has already been seen.")

        # Choose the first or next query for the base payload.
        if self._iteration == 0 and self._first_query:
            payload = self._first_query
        else:
            payload = self._next_query

        # Append the suffix as needed.
        if self._append_iteration_suffix:
            payload += "%x" % self._iteration

        # Keep track of the iteration.
        self._iteration += 1

        # Now that we've given the query packet, flip the mode to
        # receive/match.
        self._is_send_to_remote = False

        # Return the result, converted to packet form.
        return gdbremote_packet_encode_string(payload)

    def is_consumed(self):
        return self._end_matched

    def assert_match(self, asserter, actual_packet, context=None):
        # This only makes sense for matching lines coming from the remote debug
        # monitor.
        if self.is_send_to_remote():
            raise Exception(
                "assert_match() called on MultiResponseGdbRemoteEntry but state is set to send a query packet.")

        if self._end_matched:
            raise Exception(
                "assert_match() called on MultiResponseGdbRemoteEntry but end of query/response sequence has already been seen.")

        # Set up a context as needed.
        if not context:
            context = {}

        # Check if the packet matches the end condition.
        match = self._end_regex.match(actual_packet)
        if match:
            # We're done iterating.
            self._end_matched = True
            return context

        # Not done iterating - save the packet.
        context[self._save_key] = context.get(self._save_key, [])
        context[self._save_key].append(actual_packet)

        # Check for a runaway response cycle.
        if len(context[self._save_key]) >= self._runaway_response_count:
            raise Exception(
                "runaway query/response cycle detected: %d responses captured so far. Last response: %s" %
                (len(
                    context[
                        self._save_key]), context[
                    self._save_key][
                    -1]))

        # Flip the mode to send for generating the query.
        self._is_send_to_remote = True
        return context


class MatchRemoteOutputEntry(GdbRemoteEntryBase):
    """Waits for output from the debug monitor to match a regex or time out.

    This entry type tries to match each time new gdb remote output is accumulated
    using a provided regex.  If the output does not match the regex within the
    given timeframe, the command fails the playback session.  If the regex does
    match, any capture fields are recorded in the context.

    Settings accepted from params:

        regex: required. Specifies a compiled regex object that must either succeed
            with re.match or re.search (see regex_mode below) within the given timeout
            (see timeout_seconds below) or cause the playback to fail.

        regex_mode: optional. Available values: "match" or "search". If "match", the entire
            stub output as collected so far must match the regex.  If search, then the regex
            must match starting somewhere within the output text accumulated thus far.
            Default: "match" (i.e. the regex must match the entirety of the accumulated output
            buffer, so unexpected text will generally fail the match).

        capture: optional.  If specified, is a dictionary of regex match group indices (should start
            with 1) to variable names that will store the capture group indicated by the
            index. For example, {1:"thread_id"} will store capture group 1's content in the
            context dictionary where "thread_id" is the key and the match group value is
            the value. The value stored off can be used later in a expect_captures expression.
            This arg only makes sense when regex is specified.
    """

    def __init__(self, regex=None, regex_mode="match", capture=None):
        self._regex = regex
        self._regex_mode = regex_mode
        self._capture = capture
        self._matched = False

        if not self._regex:
            raise Exception("regex cannot be None")

        if not self._regex_mode in ["match", "search"]:
            raise Exception(
                "unsupported regex mode \"{}\": must be \"match\" or \"search\"".format(
                    self._regex_mode))

    def is_output_matcher(self):
        return True

    def is_send_to_remote(self):
        # This is always a "wait for remote" command.
        return False

    def is_consumed(self):
        return self._matched

    def assert_match(self, asserter, accumulated_output, context):
        # Validate args.
        if not accumulated_output:
            raise Exception("accumulated_output cannot be none")
        if not context:
            raise Exception("context cannot be none")

        # Validate that we haven't already matched.
        if self._matched:
            raise Exception(
                "invalid state - already matched, attempting to match again")

        # If we don't have any content yet, we don't match.
        if len(accumulated_output) < 1:
            return context

        # Check if we match
        if self._regex_mode == "match":
            match = self._regex.match(accumulated_output)
        elif self._regex_mode == "search":
            match = self._regex.search(accumulated_output)
        else:
            raise Exception(
                "Unexpected regex mode: {}".format(
                    self._regex_mode))

        # If we don't match, wait to try again after next $O content, or time
        # out.
        if not match:
            # print("re pattern \"{}\" did not match against \"{}\"".format(self._regex.pattern, accumulated_output))
            return context

        # We do match.
        self._matched = True
        # print("re pattern \"{}\" matched against \"{}\"".format(self._regex.pattern, accumulated_output))

        # Collect up any captures into the context.
        if self._capture:
            # Handle captures.
            for group_index, var_name in list(self._capture.items()):
                capture_text = match.group(group_index)
                if not capture_text:
                    raise Exception(
                        "No content for group index {}".format(group_index))
                context[var_name] = capture_text

        return context


class GdbRemoteTestSequence(object):

    _LOG_LINE_REGEX = re.compile(r'^.*(read|send)\s+packet:\s+(.+)$')

    def __init__(self, logger):
        self.entries = []
        self.logger = logger

    def __len__(self):
        return len(self.entries)

    def add_log_lines(self, log_lines, remote_input_is_read):
        for line in log_lines:
            if isinstance(line, str):
                # Handle log line import
                # if self.logger:
                #     self.logger.debug("processing log line: {}".format(line))
                match = self._LOG_LINE_REGEX.match(line)
                if match:
                    playback_packet = match.group(2)
                    direction = match.group(1)
                    if _is_packet_lldb_gdbserver_input(
                            direction, remote_input_is_read):
                        # Handle as something to send to the remote debug monitor.
                        # if self.logger:
                        #     self.logger.info("processed packet to send to remote: {}".format(playback_packet))
                        self.entries.append(
                            GdbRemoteEntry(
                                is_send_to_remote=True,
                                exact_payload=playback_packet))
                    else:
                        # Log line represents content to be expected from the remote debug monitor.
                        # if self.logger:
                        #     self.logger.info("receiving packet from llgs, should match: {}".format(playback_packet))
                        self.entries.append(
                            GdbRemoteEntry(
                                is_send_to_remote=False,
                                exact_payload=playback_packet))
                else:
                    raise Exception(
                        "failed to interpret log line: {}".format(line))
            elif isinstance(line, dict):
                entry_type = line.get("type", "regex_capture")
                if entry_type == "regex_capture":
                    # Handle more explicit control over details via dictionary.
                    direction = line.get("direction", None)
                    regex = line.get("regex", None)
                    capture = line.get("capture", None)
                    expect_captures = line.get("expect_captures", None)

                    # Compile the regex.
                    if regex and (isinstance(regex, str)):
                        regex = re.compile(regex)

                    if _is_packet_lldb_gdbserver_input(
                            direction, remote_input_is_read):
                        # Handle as something to send to the remote debug monitor.
                        # if self.logger:
                        #     self.logger.info("processed dict sequence to send to remote")
                        self.entries.append(
                            GdbRemoteEntry(
                                is_send_to_remote=True,
                                regex=regex,
                                capture=capture,
                                expect_captures=expect_captures))
                    else:
                        # Log line represents content to be expected from the remote debug monitor.
                        # if self.logger:
                        #     self.logger.info("processed dict sequence to match receiving from remote")
                        self.entries.append(
                            GdbRemoteEntry(
                                is_send_to_remote=False,
                                regex=regex,
                                capture=capture,
                                expect_captures=expect_captures))
                elif entry_type == "multi_response":
                    self.entries.append(MultiResponseGdbRemoteEntry(line))
                elif entry_type == "output_match":

                    regex = line.get("regex", None)
                    # Compile the regex.
                    if regex and (isinstance(regex, str)):
                        regex = re.compile(regex, re.DOTALL)

                    regex_mode = line.get("regex_mode", "match")
                    capture = line.get("capture", None)
                    self.entries.append(
                        MatchRemoteOutputEntry(
                            regex=regex,
                            regex_mode=regex_mode,
                            capture=capture))
                else:
                    raise Exception("unknown entry type \"%s\"" % entry_type)


def process_is_running(pid, unknown_value=True):
    """If possible, validate that the given pid represents a running process on the local system.

    Args:

        pid: an OS-specific representation of a process id.  Should be an integral value.

        unknown_value: value used when we cannot determine how to check running local
        processes on the OS.

    Returns:

        If we can figure out how to check running process ids on the given OS:
        return True if the process is running, or False otherwise.

        If we don't know how to check running process ids on the given OS:
        return the value provided by the unknown_value arg.
    """
    if not isinstance(pid, six.integer_types):
        raise Exception(
            "pid must be an integral type (actual type: %s)" % str(
                type(pid)))

    process_ids = []

    if lldb.remote_platform:
        # Don't know how to get list of running process IDs on a remote
        # platform
        return unknown_value
    elif platform.system() in ['Darwin', 'Linux', 'FreeBSD', 'NetBSD']:
        # Build the list of running process ids
        output = subprocess.check_output(
            "ps ax | awk '{ print $1; }'", shell=True).decode("utf-8")
        text_process_ids = output.split('\n')[1:]
        # Convert text pids to ints
        process_ids = [int(text_pid)
                       for text_pid in text_process_ids if text_pid != '']
    elif platform.system() == 'Windows':
        output = subprocess.check_output(
            "for /f \"tokens=2 delims=,\" %F in ('tasklist /nh /fi \"PID ne 0\" /fo csv') do @echo %~F", shell=True).decode("utf-8")
        text_process_ids = output.split('\n')[1:]
        process_ids = [int(text_pid)
                       for text_pid in text_process_ids if text_pid != '']
    # elif {your_platform_here}:
    #   fill in process_ids as a list of int type process IDs running on
    #   the local system.
    else:
        # Don't know how to get list of running process IDs on this
        # OS, so return the "don't know" value.
        return unknown_value

    # Check if the pid is in the process_ids
    return pid in process_ids

if __name__ == '__main__':
    EXE_PATH = get_lldb_server_exe()
    if EXE_PATH:
        print("lldb-server path detected: {}".format(EXE_PATH))
    else:
        print("lldb-server could not be found")