[PATCH 2 of 2 chg-port] osutil: implement pure version of recvfds() for PyPy

[FUJIWARA Katsunori]

At Thu, 24 Dec 2015 01:30:40 +0900,
FUJIWARA Katsunori wrote:
> 
> 
> At Sat, 19 Dec 2015 12:17:37 +0900,
> Yuya Nishihara wrote:
> > 
> > # HG changeset patch
> > # User Yuya Nishihara <yuya at tcha.org>
> > # Date 1450363989 -32400
> > #      Thu Dec 17 23:53:09 2015 +0900
> > # Node ID 9726608c61dd53832c821d8bb9ce15b8aa268466
> > # Parent  076525f412e74c913f72ff52034aa7ea046af74b
> > osutil: implement pure version of recvfds() for PyPy
> > 
> > This is less portable than the C version, but PyPy can't load CPython
> > extensions. So for now, this will be used on PyPy.
> > 
> > I've tested it on Linux amd64 and Mac OS X.
> > 
> > diff --git a/mercurial/pure/osutil.py b/mercurial/pure/osutil.py
> > --- a/mercurial/pure/osutil.py
> > +++ b/mercurial/pure/osutil.py
> > @@ -7,8 +7,12 @@
> >  
> >  from __future__ import absolute_import
> >  
> > +import ctypes
> > +import ctypes.util
> >  import os
> > +import socket
> >  import stat as statmod
> > +import sys
> >  
> >  def _mode_to_kind(mode):
> >      if statmod.S_ISREG(mode):
> > @@ -59,8 +63,87 @@ def listdir(path, stat=False, skip=None)
> >  
> >  if os.name != 'nt':
> >      posixfile = open
> > +
> > +    _SCM_RIGHTS = 0x01
> > +    _socklen_t = ctypes.c_uint
> > +
> > +    if sys.platform == 'linux2':
> > +        # socket.h says "the type should be socklen_t but the definition of
> > +        # the kernel is incompatible with this."
> > +        _cmsg_len_t = ctypes.c_size_t
> > +        _msg_controllen_t = ctypes.c_size_t
> > +        _msg_iovlen_t = ctypes.c_size_t
> > +    else:
> > +        _cmsg_len_t = _socklen_t
> > +        _msg_controllen_t = _socklen_t
> > +        _msg_iovlen_t = ctypes.c_int
> > +
> > +    class _iovec(ctypes.Structure):
> > +        _fields_ = [
> > +            ('iov_base', ctypes.c_void_p),
> > +            ('iov_len', ctypes.c_size_t),
> > +        ]
> > +
> > +    class _msghdr(ctypes.Structure):
> > +        _fields_ = [
> > +            ('msg_name', ctypes.c_void_p),
> > +            ('msg_namelen', _socklen_t),
> > +            ('msg_iov', ctypes.POINTER(_iovec)),
> > +            ('msg_iovlen', _msg_iovlen_t),
> > +            ('msg_control', ctypes.c_void_p),
> > +            ('msg_controllen', _msg_controllen_t),
> > +            ('msg_flags', ctypes.c_int),
> > +        ]
> > +
> > +    class _cmsghdr(ctypes.Structure):
> > +        _fields_ = [
> > +            ('cmsg_len', _cmsg_len_t),
> > +            ('cmsg_level', ctypes.c_int),
> > +            ('cmsg_type', ctypes.c_int),
> > +            ('cmsg_data', ctypes.c_ubyte * 0),
> > +        ]
> > +
> > +    _libc = ctypes.CDLL(ctypes.util.find_library('c'), use_errno=True)
> > +    _recvmsg = _libc.recvmsg
> > +    _recvmsg.restype = ctypes.c_ssize_t
> 
> This change doesn't work with Python 2.6.x, because ctypes.c_ssize_t
> was introduced by 2.7. Loading osutil itself is aborted.
> 
> Even if Mercurial itself will be built without pure python modules,
> "hg id -i" before building *.o in setup.py requires pure version of
> osutil module.

Oops, sorry, I overlooked Bryan's patch posting.


> 
> > +    _recvmsg.argtypes = (ctypes.c_int, ctypes.POINTER(_msghdr), ctypes.c_int)
> > +
> > +    def _CMSG_FIRSTHDR(msgh):
> > +        if msgh.msg_controllen < ctypes.sizeof(_cmsghdr):
> > +            return
> > +        cmsgptr = ctypes.cast(msgh.msg_control, ctypes.POINTER(_cmsghdr))
> > +        return cmsgptr.contents
> > +
> > +    # The pure version is less portable than the native version because the
> > +    # handling of socket ancillary data heavily depends on C preprocessor.
> > +    # Also, some length fields are wrongly typed in Linux kernel.
> > +    def recvfds(sockfd):
> > +        """receive list of file descriptors via socket"""
> > +        dummy = (ctypes.c_ubyte * 1)()
> > +        iov = _iovec(ctypes.cast(dummy, ctypes.c_void_p), ctypes.sizeof(dummy))
> > +        cbuf = ctypes.create_string_buffer(256)
> > +        msgh = _msghdr(None, 0,
> > +                       ctypes.pointer(iov), 1,
> > +                       ctypes.cast(cbuf, ctypes.c_void_p), ctypes.sizeof(cbuf),
> > +                       0)
> > +        r = _recvmsg(sockfd, ctypes.byref(msgh), 0)
> > +        if r < 0:
> > +            e = ctypes.get_errno()
> > +            raise OSError(e, os.strerror(e))
> > +        # assumes that the first cmsg has fds because it isn't easy to write
> > +        # portable CMSG_NXTHDR() with ctypes.
> > +        cmsg = _CMSG_FIRSTHDR(msgh)
> > +        if not cmsg:
> > +            return []
> > +        if (cmsg.cmsg_level != socket.SOL_SOCKET or
> > +            cmsg.cmsg_type != _SCM_RIGHTS):
> > +            return []
> > +        rfds = ctypes.cast(cmsg.cmsg_data, ctypes.POINTER(ctypes.c_int))
> > +        rfdscount = ((cmsg.cmsg_len - _cmsghdr.cmsg_data.offset) /
> > +                     ctypes.sizeof(ctypes.c_int))
> > +        return [rfds[i] for i in xrange(rfdscount)]
> > +
> >  else:
> > -    import ctypes
> >      import msvcrt
> >  
> >      _kernel32 = ctypes.windll.kernel32
> > _______________________________________________
> > Mercurial-devel mailing list
> > Mercurial-devel at selenic.com
> > https://selenic.com/mailman/listinfo/mercurial-devel
> 
> ----------------------------------------------------------------------
> [FUJIWARA Katsunori]                             foozy at lares.dti.ne.jp
> _______________________________________________
> Mercurial-devel mailing list
> Mercurial-devel at selenic.com
> https://selenic.com/mailman/listinfo/mercurial-devel

----------------------------------------------------------------------
[FUJIWARA Katsunori]                             foozy at lares.dti.ne.jp