# Copyright 2014-present Facebook, Inc. # All rights reserved. # # Redistribution and use in source and binary forms, with or without # modification, are permitted provided that the following conditions are met: # # * Redistributions of source code must retain the above copyright notice, # this list of conditions and the following disclaimer. # # * Redistributions in binary form must reproduce the above copyright notice, # this list of conditions and the following disclaimer in the documentation # and/or other materials provided with the distribution. # # * Neither the name Facebook nor the names of its contributors may be used to # endorse or promote products derived from this software without specific # prior written permission. # # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" # AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE # IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE # DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE # FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL # DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR # SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER # CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, # OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. import os import errno import math import socket import subprocess import time # Sometimes it's really hard to get Python extensions to compile, # so fall back to a pure Python implementation. try: import bser except ImportError: import pybser as bser import capabilities if os.name == 'nt': import ctypes import ctypes.wintypes wintypes = ctypes.wintypes GENERIC_READ = 0x80000000 GENERIC_WRITE = 0x40000000 FILE_FLAG_OVERLAPPED = 0x40000000 OPEN_EXISTING = 3 INVALID_HANDLE_VALUE = -1 FORMAT_MESSAGE_FROM_SYSTEM = 0x00001000 FORMAT_MESSAGE_ALLOCATE_BUFFER = 0x00000100 FORMAT_MESSAGE_IGNORE_INSERTS = 0x00000200 WAIT_TIMEOUT = 0x00000102 WAIT_OBJECT_0 = 0x00000000 ERROR_IO_PENDING = 997 class OVERLAPPED(ctypes.Structure): _fields_ = [ ("Internal", wintypes.ULONG), ("InternalHigh", wintypes.ULONG), ("Offset", wintypes.DWORD), ("OffsetHigh", wintypes.DWORD), ("hEvent", wintypes.HANDLE) ] def __init__(self): self.Offset = 0 self.OffsetHigh = 0 self.hEvent = 0 LPDWORD = ctypes.POINTER(wintypes.DWORD) CreateFile = ctypes.windll.kernel32.CreateFileA CreateFile.argtypes = [wintypes.LPSTR, wintypes.DWORD, wintypes.DWORD, wintypes.LPVOID, wintypes.DWORD, wintypes.DWORD, wintypes.HANDLE] CreateFile.restype = wintypes.HANDLE CloseHandle = ctypes.windll.kernel32.CloseHandle CloseHandle.argtypes = [wintypes.HANDLE] CloseHandle.restype = wintypes.BOOL ReadFile = ctypes.windll.kernel32.ReadFile ReadFile.argtypes = [wintypes.HANDLE, wintypes.LPVOID, wintypes.DWORD, LPDWORD, ctypes.POINTER(OVERLAPPED)] ReadFile.restype = wintypes.BOOL WriteFile = ctypes.windll.kernel32.WriteFile WriteFile.argtypes = [wintypes.HANDLE, wintypes.LPVOID, wintypes.DWORD, LPDWORD, ctypes.POINTER(OVERLAPPED)] WriteFile.restype = wintypes.BOOL GetLastError = ctypes.windll.kernel32.GetLastError GetLastError.argtypes = [] GetLastError.restype = wintypes.DWORD FormatMessage = ctypes.windll.kernel32.FormatMessageA FormatMessage.argtypes = [wintypes.DWORD, wintypes.LPVOID, wintypes.DWORD, wintypes.DWORD, ctypes.POINTER(wintypes.LPSTR), wintypes.DWORD, wintypes.LPVOID] FormatMessage.restype = wintypes.DWORD LocalFree = ctypes.windll.kernel32.LocalFree GetOverlappedResultEx = ctypes.windll.kernel32.GetOverlappedResultEx GetOverlappedResultEx.argtypes = [wintypes.HANDLE, ctypes.POINTER(OVERLAPPED), LPDWORD, wintypes.DWORD, wintypes.BOOL] GetOverlappedResultEx.restype = wintypes.BOOL CancelIoEx = ctypes.windll.kernel32.CancelIoEx CancelIoEx.argtypes = [wintypes.HANDLE, ctypes.POINTER(OVERLAPPED)] CancelIoEx.restype = wintypes.BOOL # 2 bytes marker, 1 byte int size, 8 bytes int64 value sniff_len = 13 # This is a helper for debugging the client. _debugging = False if _debugging: def log(fmt, *args): print('[%s] %s' % (time.strftime("%a, %d %b %Y %H:%M:%S", time.gmtime()), fmt % args[:])) else: def log(fmt, *args): pass class WatchmanError(Exception): pass class SocketTimeout(WatchmanError): """A specialized exception raised for socket timeouts during communication to/from watchman. This makes it easier to implement non-blocking loops as callers can easily distinguish between a routine timeout and an actual error condition. Note that catching WatchmanError will also catch this as it is a super-class, so backwards compatibility in exception handling is preserved. """ class CommandError(WatchmanError): """error returned by watchman self.msg is the message returned by watchman. """ def __init__(self, msg, cmd=None): self.msg = msg self.cmd = cmd super(CommandError, self).__init__('watchman command error: %s' % msg) def setCommand(self, cmd): self.cmd = cmd def __str__(self): if self.cmd: return '%s, while executing %s' % (self.msg, self.cmd) return self.msg class Transport(object): """ communication transport to the watchman server """ buf = None def close(self): """ tear it down """ raise NotImplementedError() def readBytes(self, size): """ read size bytes """ raise NotImplementedError() def write(self, buf): """ write some data """ raise NotImplementedError() def setTimeout(self, value): pass def readLine(self): """ read a line Maintains its own buffer, callers of the transport should not mix calls to readBytes and readLine. """ if self.buf is None: self.buf = [] # Buffer may already have a line if we've received unilateral # response(s) from the server if len(self.buf) == 1 and "\n" in self.buf[0]: (line, b) = self.buf[0].split("\n", 1) self.buf = [b] return line while True: b = self.readBytes(4096) if "\n" in b: result = ''.join(self.buf) (line, b) = b.split("\n", 1) self.buf = [b] return result + line self.buf.append(b) class Codec(object): """ communication encoding for the watchman server """ transport = None def __init__(self, transport): self.transport = transport def receive(self): raise NotImplementedError() def send(self, *args): raise NotImplementedError() def setTimeout(self, value): self.transport.setTimeout(value) class UnixSocketTransport(Transport): """ local unix domain socket transport """ sock = None def __init__(self, sockpath, timeout): self.sockpath = sockpath self.timeout = timeout sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM) try: sock.settimeout(self.timeout) sock.connect(self.sockpath) self.sock = sock except socket.error as e: raise WatchmanError('unable to connect to %s: %s' % (self.sockpath, e)) def close(self): self.sock.close() self.sock = None def setTimeout(self, value): self.timeout = value self.sock.settimeout(self.timeout) def readBytes(self, size): try: buf = [self.sock.recv(size)] if not buf[0]: raise WatchmanError('empty watchman response') return buf[0] except socket.timeout: raise SocketTimeout('timed out waiting for response') def write(self, data): try: self.sock.sendall(data) except socket.timeout: raise SocketTimeout('timed out sending query command') class WindowsNamedPipeTransport(Transport): """ connect to a named pipe """ def __init__(self, sockpath, timeout): self.sockpath = sockpath self.timeout = int(math.ceil(timeout * 1000)) self._iobuf = None self.pipe = CreateFile(sockpath, GENERIC_READ | GENERIC_WRITE, 0, None, OPEN_EXISTING, FILE_FLAG_OVERLAPPED, None) if self.pipe == INVALID_HANDLE_VALUE: self.pipe = None self._raise_win_err('failed to open pipe %s' % sockpath, GetLastError()) def _win32_strerror(self, err): """ expand a win32 error code into a human readable message """ # FormatMessage will allocate memory and assign it here buf = ctypes.c_char_p() FormatMessage( FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_IGNORE_INSERTS, None, err, 0, buf, 0, None) try: return buf.value finally: LocalFree(buf) def _raise_win_err(self, msg, err): raise IOError('%s win32 error code: %d %s' % (msg, err, self._win32_strerror(err))) def close(self): if self.pipe: CloseHandle(self.pipe) self.pipe = None def readBytes(self, size): """ A read can block for an unbounded amount of time, even if the kernel reports that the pipe handle is signalled, so we need to always perform our reads asynchronously """ # try to satisfy the read from any buffered data if self._iobuf: if size >= len(self._iobuf): res = self._iobuf self.buf = None return res res = self._iobuf[:size] self._iobuf = self._iobuf[size:] return res # We need to initiate a read buf = ctypes.create_string_buffer(size) olap = OVERLAPPED() log('made read buff of size %d', size) # ReadFile docs warn against sending in the nread parameter for async # operations, so we always collect it via GetOverlappedResultEx immediate = ReadFile(self.pipe, buf, size, None, olap) if not immediate: err = GetLastError() if err != ERROR_IO_PENDING: self._raise_win_err('failed to read %d bytes' % size, GetLastError()) nread = wintypes.DWORD() if not GetOverlappedResultEx(self.pipe, olap, nread, 0 if immediate else self.timeout, True): err = GetLastError() CancelIoEx(self.pipe, olap) if err == WAIT_TIMEOUT: log('GetOverlappedResultEx timedout') raise SocketTimeout('timed out after waiting %dms for read' % self.timeout) log('GetOverlappedResultEx reports error %d', err) self._raise_win_err('error while waiting for read', err) nread = nread.value if nread == 0: # Docs say that named pipes return 0 byte when the other end did # a zero byte write. Since we don't ever do that, the only # other way this shows up is if the client has gotten in a weird # state, so let's bail out CancelIoEx(self.pipe, olap) raise IOError('Async read yielded 0 bytes; unpossible!') # Holds precisely the bytes that we read from the prior request buf = buf[:nread] returned_size = min(nread, size) if returned_size == nread: return buf # keep any left-overs around for a later read to consume self._iobuf = buf[returned_size:] return buf[:returned_size] def write(self, data): olap = OVERLAPPED() immediate = WriteFile(self.pipe, ctypes.c_char_p(data), len(data), None, olap) if not immediate: err = GetLastError() if err != ERROR_IO_PENDING: self._raise_win_err('failed to write %d bytes' % len(data), GetLastError()) # Obtain results, waiting if needed nwrote = wintypes.DWORD() if GetOverlappedResultEx(self.pipe, olap, nwrote, 0 if immediate else self.timeout, True): return nwrote.value err = GetLastError() # It's potentially unsafe to allow the write to continue after # we unwind, so let's make a best effort to avoid that happening CancelIoEx(self.pipe, olap) if err == WAIT_TIMEOUT: raise SocketTimeout('timed out after waiting %dms for write' % self.timeout) self._raise_win_err('error while waiting for write of %d bytes' % len(data), err) class CLIProcessTransport(Transport): """ open a pipe to the cli to talk to the service This intended to be used only in the test harness! The CLI is an oddball because we only support JSON input and cannot send multiple commands through the same instance, so we spawn a new process for each command. We disable server spawning for this implementation, again, because it is intended to be used only in our test harness. You really should not need to use the CLI transport for anything real. While the CLI can output in BSER, our Transport interface doesn't support telling this instance that it should do so. That effectively limits this implementation to JSON input and output only at this time. It is the responsibility of the caller to set the send and receive codecs appropriately. """ proc = None closed = True def __init__(self, sockpath, timeout): self.sockpath = sockpath self.timeout = timeout def close(self): if self.proc: self.proc.kill() self.proc = None def _connect(self): if self.proc: return self.proc args = [ 'watchman', '--sockname={}'.format(self.sockpath), '--logfile=/BOGUS', '--statefile=/BOGUS', '--no-spawn', '--no-local', '--no-pretty', '-j', ] self.proc = subprocess.Popen(args, stdin=subprocess.PIPE, stdout=subprocess.PIPE) return self.proc def readBytes(self, size): self._connect() res = self.proc.stdout.read(size) if res == '': raise WatchmanError('EOF on CLI process transport') return res def write(self, data): if self.closed: self.closed = False self.proc = None self._connect() res = self.proc.stdin.write(data) self.proc.stdin.close() self.closed = True return res class BserCodec(Codec): """ use the BSER encoding. This is the default, preferred codec """ def _loads(self, response): return bser.loads(response) def receive(self): buf = [self.transport.readBytes(sniff_len)] if not buf[0]: raise WatchmanError('empty watchman response') elen = bser.pdu_len(buf[0]) rlen = len(buf[0]) while elen > rlen: buf.append(self.transport.readBytes(elen - rlen)) rlen += len(buf[-1]) response = ''.join(buf) try: res = self._loads(response) return res except ValueError as e: raise WatchmanError('watchman response decode error: %s' % e) def send(self, *args): cmd = bser.dumps(*args) self.transport.write(cmd) class ImmutableBserCodec(BserCodec): """ use the BSER encoding, decoding values using the newer immutable object support """ def _loads(self, response): return bser.loads(response, False) class JsonCodec(Codec): """ Use json codec. This is here primarily for testing purposes """ json = None def __init__(self, transport): super(JsonCodec, self).__init__(transport) # optional dep on json, only if JsonCodec is used import json self.json = json def receive(self): line = self.transport.readLine() try: return self.json.loads(line) except Exception as e: print(e, line) raise def send(self, *args): cmd = self.json.dumps(*args) self.transport.write(cmd + "\n") class client(object): """ Handles the communication with the watchman service """ sockpath = None transport = None sendCodec = None recvCodec = None sendConn = None recvConn = None subs = {} # Keyed by subscription name sub_by_root = {} # Keyed by root, then by subscription name logs = [] # When log level is raised unilateral = ['log', 'subscription'] tport = None useImmutableBser = None def __init__(self, sockpath=None, timeout=1.0, transport=None, sendEncoding=None, recvEncoding=None, useImmutableBser=False): self.sockpath = sockpath self.timeout = timeout self.useImmutableBser = useImmutableBser transport = transport or os.getenv('WATCHMAN_TRANSPORT') or 'local' if transport == 'local' and os.name == 'nt': self.transport = WindowsNamedPipeTransport elif transport == 'local': self.transport = UnixSocketTransport elif transport == 'cli': self.transport = CLIProcessTransport if sendEncoding is None: sendEncoding = 'json' if recvEncoding is None: recvEncoding = sendEncoding else: raise WatchmanError('invalid transport %s' % transport) sendEncoding = sendEncoding or os.getenv('WATCHMAN_ENCODING') or 'bser' recvEncoding = recvEncoding or os.getenv('WATCHMAN_ENCODING') or 'bser' self.recvCodec = self._parseEncoding(recvEncoding) self.sendCodec = self._parseEncoding(sendEncoding) def _parseEncoding(self, enc): if enc == 'bser': if self.useImmutableBser: return ImmutableBserCodec return BserCodec elif enc == 'json': return JsonCodec else: raise WatchmanError('invalid encoding %s' % enc) def _hasprop(self, result, name): if self.useImmutableBser: return hasattr(result, name) return name in result def _resolvesockname(self): # if invoked via a trigger, watchman will set this env var; we # should use it unless explicitly set otherwise path = os.getenv('WATCHMAN_SOCK') if path: return path cmd = ['watchman', '--output-encoding=bser', 'get-sockname'] try: p = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE, close_fds=os.name != 'nt') except OSError as e: raise WatchmanError('"watchman" executable not in PATH (%s)', e) stdout, stderr = p.communicate() exitcode = p.poll() if exitcode: raise WatchmanError("watchman exited with code %d" % exitcode) result = bser.loads(stdout) if 'error' in result: raise WatchmanError('get-sockname error: %s' % result['error']) return result['sockname'] def _connect(self): """ establish transport connection """ if self.recvConn: return if self.sockpath is None: self.sockpath = self._resolvesockname() self.tport = self.transport(self.sockpath, self.timeout) self.sendConn = self.sendCodec(self.tport) self.recvConn = self.recvCodec(self.tport) def __del__(self): self.close() def close(self): if self.tport: self.tport.close() self.tport = None self.recvConn = None self.sendConn = None def receive(self): """ receive the next PDU from the watchman service If the client has activated subscriptions or logs then this PDU may be a unilateral PDU sent by the service to inform the client of a log event or subscription change. It may also simply be the response portion of a request initiated by query. There are clients in production that subscribe and call this in a loop to retrieve all subscription responses, so care should be taken when making changes here. """ self._connect() result = self.recvConn.receive() if self._hasprop(result, 'error'): raise CommandError(result['error']) if self._hasprop(result, 'log'): self.logs.append(result['log']) if self._hasprop(result, 'subscription'): sub = result['subscription'] if not (sub in self.subs): self.subs[sub] = [] self.subs[sub].append(result) # also accumulate in {root,sub} keyed store root = os.path.normcase(result['root']) if not root in self.sub_by_root: self.sub_by_root[root] = {} if not sub in self.sub_by_root[root]: self.sub_by_root[root][sub] = [] self.sub_by_root[root][sub].append(result) return result def isUnilateralResponse(self, res): for k in self.unilateral: if k in res: return True return False def getLog(self, remove=True): """ Retrieve buffered log data If remove is true the data will be removed from the buffer. Otherwise it will be left in the buffer """ res = self.logs if remove: self.logs = [] return res def getSubscription(self, name, remove=True, root=None): """ Retrieve the data associated with a named subscription If remove is True (the default), the subscription data is removed from the buffer. Otherwise the data is returned but left in the buffer. Returns None if there is no data associated with `name` If root is not None, then only return the subscription data that matches both root and name. When used in this way, remove processing impacts both the unscoped and scoped stores for the subscription data. """ if root is not None: if not root in self.sub_by_root: return None if not name in self.sub_by_root[root]: return None sub = self.sub_by_root[root][name] if remove: del self.sub_by_root[root][name] # don't let this grow unbounded if name in self.subs: del self.subs[name] return sub if not (name in self.subs): return None sub = self.subs[name] if remove: del self.subs[name] return sub def query(self, *args): """ Send a query to the watchman service and return the response This call will block until the response is returned. If any unilateral responses are sent by the service in between the request-response they will be buffered up in the client object and NOT returned via this method. """ log('calling client.query') self._connect() try: self.sendConn.send(args) res = self.receive() while self.isUnilateralResponse(res): res = self.receive() return res except CommandError as ex: ex.setCommand(args) raise ex def capabilityCheck(self, optional=None, required=None): """ Perform a server capability check """ res = self.query('version', { 'optional': optional or [], 'required': required or [] }) if not self._hasprop(res, 'capabilities'): # Server doesn't support capabilities, so we need to # synthesize the results based on the version capabilities.synthesize(res, optional) if 'error' in res: raise CommandError(res['error']) return res def setTimeout(self, value): self.recvConn.setTimeout(value) self.sendConn.setTimeout(value) # no-check-code -- this is a 3rd party library