--- a/mercurial/cext/osutil.c	Mon Jun 06 13:58:32 2022 +0400
+++ b/mercurial/cext/osutil.c	Thu Jun 02 23:57:56 2022 +0200
@@ -685,75 +685,6 @@
 	return NULL;
 }
 
-/*
- * recvfds() simply does not release GIL during blocking io operation because
- * command server is known to be single-threaded.
- *
- * Old systems such as Solaris don't provide CMSG_LEN, msg_control, etc.
- * Currently, recvfds() is not supported on these platforms.
- */
-#ifdef CMSG_LEN
-
-static ssize_t recvfdstobuf(int sockfd, int **rfds, void *cbuf, size_t cbufsize)
-{
-	char dummy[1];
-	struct iovec iov = {dummy, sizeof(dummy)};
-	struct msghdr msgh = {0};
-	struct cmsghdr *cmsg;
-
-	msgh.msg_iov = &iov;
-	msgh.msg_iovlen = 1;
-	msgh.msg_control = cbuf;
-	msgh.msg_controllen = (socklen_t)cbufsize;
-	if (recvmsg(sockfd, &msgh, 0) < 0)
-		return -1;
-
-	for (cmsg = CMSG_FIRSTHDR(&msgh); cmsg;
-	     cmsg = CMSG_NXTHDR(&msgh, cmsg)) {
-		if (cmsg->cmsg_level != SOL_SOCKET ||
-		    cmsg->cmsg_type != SCM_RIGHTS)
-			continue;
-		*rfds = (int *)CMSG_DATA(cmsg);
-		return (cmsg->cmsg_len - CMSG_LEN(0)) / sizeof(int);
-	}
-
-	*rfds = cbuf;
-	return 0;
-}
-
-static PyObject *recvfds(PyObject *self, PyObject *args)
-{
-	int sockfd;
-	int *rfds = NULL;
-	ssize_t rfdscount, i;
-	char cbuf[256];
-	PyObject *rfdslist = NULL;
-
-	if (!PyArg_ParseTuple(args, "i", &sockfd))
-		return NULL;
-
-	rfdscount = recvfdstobuf(sockfd, &rfds, cbuf, sizeof(cbuf));
-	if (rfdscount < 0)
-		return PyErr_SetFromErrno(PyExc_OSError);
-
-	rfdslist = PyList_New(rfdscount);
-	if (!rfdslist)
-		goto bail;
-	for (i = 0; i < rfdscount; i++) {
-		PyObject *obj = PyLong_FromLong(rfds[i]);
-		if (!obj)
-			goto bail;
-		PyList_SET_ITEM(rfdslist, i, obj);
-	}
-	return rfdslist;
-
-bail:
-	Py_XDECREF(rfdslist);
-	return NULL;
-}
-
-#endif /* CMSG_LEN */
-
 /* allow disabling setprocname via compiler flags */
 #ifndef SETPROCNAME_USE_NONE
 #if defined(HAVE_SETPROCTITLE)
@@ -1285,10 +1216,6 @@
 	{"statfiles", (PyCFunction)statfiles, METH_VARARGS | METH_KEYWORDS,
 	 "stat a series of files or symlinks\n"
 "Returns None for non-existent entries and entries of other types.\n"},
-#ifdef CMSG_LEN
-	{"recvfds", (PyCFunction)recvfds, METH_VARARGS,
-	 "receive list of file descriptors via socket\n"},
-#endif
 #ifndef SETPROCNAME_USE_NONE
 	{"setprocname", (PyCFunction)setprocname, METH_VARARGS,
 	 "set process title (best-effort)\n"},

--- a/mercurial/cext/osutil.pyi	Mon Jun 06 13:58:32 2022 +0400
+++ b/mercurial/cext/osutil.pyi	Thu Jun 02 23:57:56 2022 +0200
@@ -18,7 +18,6 @@
 def listdir(path: bytes, st: bool, skip: bool) -> List[stat]: ...
 def posixfile(name: AnyStr, mode: bytes, buffering: int) -> IO: ...
 def statfiles(names: Sequence[bytes]) -> List[stat]: ...
-def recvfds(sockfd: int) -> List[int]: ...
 def setprocname(name: bytes) -> None: ...
 def getfstype(path: bytes) -> bytes: ...
 def getfsmountpoint(path: bytes) -> bytes: ...

--- a/mercurial/chgserver.py	Mon Jun 06 13:58:32 2022 +0400
+++ b/mercurial/chgserver.py	Thu Jun 02 23:57:56 2022 +0200
@@ -389,7 +389,17 @@
         # tell client to sendmsg() with 1-byte payload, which makes it
         # distinctive from "attachio\n" command consumed by client.read()
         self.clientsock.sendall(struct.pack(b'>cI', b'I', 1))
-        clientfds = util.recvfds(self.clientsock.fileno())
+
+        data, ancdata, msg_flags, address = self.clientsock.recvmsg(1, 256)
+        assert len(ancdata) == 1
+        cmsg_level, cmsg_type, cmsg_data = ancdata[0]
+        assert cmsg_level == socket.SOL_SOCKET
+        assert cmsg_type == socket.SCM_RIGHTS
+        # memoryview.cast() was added in typeshed 61600d68772a, but pytype
+        # still complains
+        # pytype: disable=attribute-error
+        clientfds = memoryview(cmsg_data).cast('i').tolist()
+        # pytype: enable=attribute-error
         self.ui.log(b'chgserver', b'received fds: %r\n', clientfds)
 
         ui = self.ui

--- a/mercurial/pure/osutil.py	Mon Jun 06 13:58:32 2022 +0400
+++ b/mercurial/pure/osutil.py	Thu Jun 02 23:57:56 2022 +0200
@@ -9,7 +9,6 @@
 import ctypes
 import ctypes.util
 import os
-import socket
 import stat as statmod
 
 from ..pycompat import getattr
@@ -71,102 +70,6 @@
 if not pycompat.iswindows:
     posixfile = open
 
-    _SCM_RIGHTS = 0x01
-    _socklen_t = ctypes.c_uint
-
-    if pycompat.sysplatform.startswith(b'linux'):
-        # 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_ = [
-            (u'iov_base', ctypes.c_void_p),
-            (u'iov_len', ctypes.c_size_t),
-        ]
-
-    class _msghdr(ctypes.Structure):
-        _fields_ = [
-            (u'msg_name', ctypes.c_void_p),
-            (u'msg_namelen', _socklen_t),
-            (u'msg_iov', ctypes.POINTER(_iovec)),
-            (u'msg_iovlen', _msg_iovlen_t),
-            (u'msg_control', ctypes.c_void_p),
-            (u'msg_controllen', _msg_controllen_t),
-            (u'msg_flags', ctypes.c_int),
-        ]
-
-    class _cmsghdr(ctypes.Structure):
-        _fields_ = [
-            (u'cmsg_len', _cmsg_len_t),
-            (u'cmsg_level', ctypes.c_int),
-            (u'cmsg_type', ctypes.c_int),
-            (u'cmsg_data', ctypes.c_ubyte * 0),
-        ]
-
-    _libc = ctypes.CDLL(ctypes.util.find_library(u'c'), use_errno=True)
-    _recvmsg = getattr(_libc, 'recvmsg', None)
-    if _recvmsg:
-        _recvmsg.restype = getattr(ctypes, 'c_ssize_t', ctypes.c_long)
-        _recvmsg.argtypes = (
-            ctypes.c_int,
-            ctypes.POINTER(_msghdr),
-            ctypes.c_int,
-        )
-    else:
-        # recvmsg isn't always provided by libc; such systems are unsupported
-        def _recvmsg(sockfd, msg, flags):
-            raise NotImplementedError(b'unsupported platform')
-
-    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 pycompat.xrange(rfdscount)]
-
 
 else:
     import msvcrt

--- a/mercurial/util.py	Mon Jun 06 13:58:32 2022 +0400
+++ b/mercurial/util.py	Thu Jun 02 23:57:56 2022 +0200
@@ -156,11 +156,6 @@
 SERVERROLE = compression.SERVERROLE
 CLIENTROLE = compression.CLIENTROLE
 
-try:
-    recvfds = osutil.recvfds
-except AttributeError:
-    pass
-
 # Python compatibility
 
 _notset = object()