ed47d6ba76
The rpc only reports one field, i.e. the cgroup driver, to kubelet. Containerd determines the effective cgroup driver by looking at all runtime handlers, starting from the default runtime handler (the rest in alphabetical order), and returning the cgroup driver setting of the first runtime handler that supports one. If no runtime handler supports cgroup driver (i.e. has a config option for it) containerd falls back to auto-detection, returning systemd if systemd is running and cgroupfs otherwise. This patch implements the CRI server side of Kubernetes KEP-4033: https://github.com/kubernetes/enhancements/tree/master/keps/sig-node/4033-group-driver-detection-over-cri Signed-off-by: Markus Lehtonen <markus.lehtonen@intel.com>
97 lines
3.0 KiB
Go
97 lines
3.0 KiB
Go
package utils
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/*
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* Copyright 2016, 2017 SUSE LLC
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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import (
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"fmt"
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"os"
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"golang.org/x/sys/unix"
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)
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// MaxSendfdLen is the maximum length of the name of a file descriptor being
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// sent using SendFd. The name of the file handle returned by RecvFd will never
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// be larger than this value.
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const MaxNameLen = 4096
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// oobSpace is the size of the oob slice required to store a single FD. Note
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// that unix.UnixRights appears to make the assumption that fd is always int32,
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// so sizeof(fd) = 4.
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var oobSpace = unix.CmsgSpace(4)
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// RecvFd waits for a file descriptor to be sent over the given AF_UNIX
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// socket. The file name of the remote file descriptor will be recreated
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// locally (it is sent as non-auxiliary data in the same payload).
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func RecvFd(socket *os.File) (*os.File, error) {
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// For some reason, unix.Recvmsg uses the length rather than the capacity
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// when passing the msg_controllen and other attributes to recvmsg. So we
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// have to actually set the length.
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name := make([]byte, MaxNameLen)
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oob := make([]byte, oobSpace)
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sockfd := socket.Fd()
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n, oobn, _, _, err := unix.Recvmsg(int(sockfd), name, oob, 0)
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if err != nil {
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return nil, err
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}
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if n >= MaxNameLen || oobn != oobSpace {
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return nil, fmt.Errorf("recvfd: incorrect number of bytes read (n=%d oobn=%d)", n, oobn)
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}
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// Truncate.
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name = name[:n]
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oob = oob[:oobn]
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scms, err := unix.ParseSocketControlMessage(oob)
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if err != nil {
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return nil, err
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}
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if len(scms) != 1 {
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return nil, fmt.Errorf("recvfd: number of SCMs is not 1: %d", len(scms))
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}
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scm := scms[0]
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fds, err := unix.ParseUnixRights(&scm)
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if err != nil {
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return nil, err
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}
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if len(fds) != 1 {
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return nil, fmt.Errorf("recvfd: number of fds is not 1: %d", len(fds))
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}
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fd := uintptr(fds[0])
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return os.NewFile(fd, string(name)), nil
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}
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// SendFd sends a file descriptor over the given AF_UNIX socket. In
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// addition, the file.Name() of the given file will also be sent as
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// non-auxiliary data in the same payload (allowing to send contextual
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// information for a file descriptor).
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func SendFd(socket *os.File, name string, fd uintptr) error {
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if len(name) >= MaxNameLen {
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return fmt.Errorf("sendfd: filename too long: %s", name)
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}
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return SendFds(socket, []byte(name), int(fd))
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}
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// SendFds sends a list of files descriptor and msg over the given AF_UNIX socket.
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func SendFds(socket *os.File, msg []byte, fds ...int) error {
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oob := unix.UnixRights(fds...)
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return unix.Sendmsg(int(socket.Fd()), msg, oob, nil, 0)
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}
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