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a9b00f4522
Because unix-mode server forks child process per connection, client does not know the pid of the server that will handle requests. The pid is necessary to interrupt hung process: 1. client connects to socket server 2. server accepts the connection, forks, and tells pid 3. client requests "runcommand pull" .. hung .. 4. client sends SIGINT to the (forked) server 5. server returns from I/O wait Note that getsockopt(SO_PEERCRED) of Linux cannot be used because the server fork()s after accept().
322 lines
9.2 KiB
Python
322 lines
9.2 KiB
Python
# commandserver.py - communicate with Mercurial's API over a pipe
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#
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# Copyright Matt Mackall <mpm@selenic.com>
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#
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# This software may be used and distributed according to the terms of the
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# GNU General Public License version 2 or any later version.
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from i18n import _
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import struct
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import sys, os, errno, traceback, SocketServer
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import dispatch, encoding, util
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logfile = None
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def log(*args):
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if not logfile:
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return
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for a in args:
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logfile.write(str(a))
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logfile.flush()
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class channeledoutput(object):
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"""
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Write data to out in the following format:
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data length (unsigned int),
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data
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"""
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def __init__(self, out, channel):
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self.out = out
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self.channel = channel
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def write(self, data):
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if not data:
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return
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self.out.write(struct.pack('>cI', self.channel, len(data)))
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self.out.write(data)
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self.out.flush()
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def __getattr__(self, attr):
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if attr in ('isatty', 'fileno'):
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raise AttributeError(attr)
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return getattr(self.out, attr)
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class channeledinput(object):
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"""
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Read data from in_.
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Requests for input are written to out in the following format:
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channel identifier - 'I' for plain input, 'L' line based (1 byte)
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how many bytes to send at most (unsigned int),
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The client replies with:
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data length (unsigned int), 0 meaning EOF
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data
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"""
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maxchunksize = 4 * 1024
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def __init__(self, in_, out, channel):
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self.in_ = in_
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self.out = out
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self.channel = channel
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def read(self, size=-1):
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if size < 0:
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# if we need to consume all the clients input, ask for 4k chunks
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# so the pipe doesn't fill up risking a deadlock
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size = self.maxchunksize
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s = self._read(size, self.channel)
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buf = s
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while s:
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s = self._read(size, self.channel)
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buf += s
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return buf
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else:
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return self._read(size, self.channel)
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def _read(self, size, channel):
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if not size:
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return ''
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assert size > 0
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# tell the client we need at most size bytes
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self.out.write(struct.pack('>cI', channel, size))
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self.out.flush()
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length = self.in_.read(4)
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length = struct.unpack('>I', length)[0]
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if not length:
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return ''
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else:
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return self.in_.read(length)
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def readline(self, size=-1):
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if size < 0:
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size = self.maxchunksize
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s = self._read(size, 'L')
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buf = s
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# keep asking for more until there's either no more or
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# we got a full line
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while s and s[-1] != '\n':
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s = self._read(size, 'L')
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buf += s
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return buf
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else:
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return self._read(size, 'L')
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def __iter__(self):
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return self
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def next(self):
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l = self.readline()
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if not l:
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raise StopIteration
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return l
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def __getattr__(self, attr):
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if attr in ('isatty', 'fileno'):
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raise AttributeError(attr)
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return getattr(self.in_, attr)
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class server(object):
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"""
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Listens for commands on fin, runs them and writes the output on a channel
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based stream to fout.
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"""
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def __init__(self, ui, repo, fin, fout):
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self.cwd = os.getcwd()
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logpath = ui.config("cmdserver", "log", None)
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if logpath:
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global logfile
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if logpath == '-':
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# write log on a special 'd' (debug) channel
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logfile = channeledoutput(fout, 'd')
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else:
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logfile = open(logpath, 'a')
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if repo:
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# the ui here is really the repo ui so take its baseui so we don't
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# end up with its local configuration
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self.ui = repo.baseui
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self.repo = repo
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self.repoui = repo.ui
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else:
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self.ui = ui
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self.repo = self.repoui = None
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self.cerr = channeledoutput(fout, 'e')
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self.cout = channeledoutput(fout, 'o')
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self.cin = channeledinput(fin, fout, 'I')
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self.cresult = channeledoutput(fout, 'r')
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self.client = fin
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def _read(self, size):
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if not size:
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return ''
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data = self.client.read(size)
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# is the other end closed?
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if not data:
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raise EOFError
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return data
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def runcommand(self):
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""" reads a list of \0 terminated arguments, executes
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and writes the return code to the result channel """
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length = struct.unpack('>I', self._read(4))[0]
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if not length:
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args = []
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else:
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args = self._read(length).split('\0')
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# copy the uis so changes (e.g. --config or --verbose) don't
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# persist between requests
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copiedui = self.ui.copy()
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uis = [copiedui]
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if self.repo:
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self.repo.baseui = copiedui
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# clone ui without using ui.copy because this is protected
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repoui = self.repoui.__class__(self.repoui)
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repoui.copy = copiedui.copy # redo copy protection
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uis.append(repoui)
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self.repo.ui = self.repo.dirstate._ui = repoui
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self.repo.invalidateall()
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for ui in uis:
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# any kind of interaction must use server channels
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ui.setconfig('ui', 'nontty', 'true', 'commandserver')
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req = dispatch.request(args[:], copiedui, self.repo, self.cin,
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self.cout, self.cerr)
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ret = (dispatch.dispatch(req) or 0) & 255 # might return None
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# restore old cwd
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if '--cwd' in args:
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os.chdir(self.cwd)
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self.cresult.write(struct.pack('>i', int(ret)))
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def getencoding(self):
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""" writes the current encoding to the result channel """
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self.cresult.write(encoding.encoding)
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def serveone(self):
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cmd = self.client.readline()[:-1]
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if cmd:
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handler = self.capabilities.get(cmd)
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if handler:
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handler(self)
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else:
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# clients are expected to check what commands are supported by
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# looking at the servers capabilities
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raise util.Abort(_('unknown command %s') % cmd)
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return cmd != ''
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capabilities = {'runcommand' : runcommand,
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'getencoding' : getencoding}
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def serve(self):
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hellomsg = 'capabilities: ' + ' '.join(sorted(self.capabilities))
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hellomsg += '\n'
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hellomsg += 'encoding: ' + encoding.encoding
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hellomsg += '\n'
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hellomsg += 'pid: %d' % os.getpid()
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# write the hello msg in -one- chunk
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self.cout.write(hellomsg)
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try:
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while self.serveone():
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pass
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except EOFError:
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# we'll get here if the client disconnected while we were reading
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# its request
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return 1
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return 0
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class pipeservice(object):
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def __init__(self, ui, repo, opts):
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self.server = server(ui, repo, sys.stdin, sys.stdout)
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def init(self):
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pass
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def run(self):
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return self.server.serve()
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class _requesthandler(SocketServer.StreamRequestHandler):
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def handle(self):
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ui = self.server.ui
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repo = self.server.repo
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sv = server(ui, repo, self.rfile, self.wfile)
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try:
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try:
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sv.serve()
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# handle exceptions that may be raised by command server. most of
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# known exceptions are caught by dispatch.
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except util.Abort, inst:
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ui.warn(_('abort: %s\n') % inst)
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except IOError, inst:
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if inst.errno != errno.EPIPE:
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raise
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except KeyboardInterrupt:
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pass
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except: # re-raises
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# also write traceback to error channel. otherwise client cannot
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# see it because it is written to server's stderr by default.
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traceback.print_exc(file=sv.cerr)
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raise
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class unixservice(object):
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"""
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Listens on unix domain socket and forks server per connection
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"""
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def __init__(self, ui, repo, opts):
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self.ui = ui
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self.repo = repo
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self.address = opts['address']
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if not util.safehasattr(SocketServer, 'UnixStreamServer'):
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raise util.Abort(_('unsupported platform'))
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if not self.address:
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raise util.Abort(_('no socket path specified with --address'))
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def init(self):
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class cls(SocketServer.ForkingMixIn, SocketServer.UnixStreamServer):
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ui = self.ui
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repo = self.repo
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self.server = cls(self.address, _requesthandler)
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self.ui.status(_('listening at %s\n') % self.address)
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self.ui.flush() # avoid buffering of status message
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def run(self):
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try:
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self.server.serve_forever()
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finally:
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os.unlink(self.address)
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_servicemap = {
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'pipe': pipeservice,
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'unix': unixservice,
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}
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def createservice(ui, repo, opts):
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mode = opts['cmdserver']
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try:
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return _servicemap[mode](ui, repo, opts)
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except KeyError:
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raise util.Abort(_('unknown mode %s') % mode)
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