mirror of
https://github.com/aljazceru/kata-containers.git
synced 2026-01-04 23:14:19 +01:00
045c7ae9a3
Add functions to convert a host device to a cgroup device or linux device, the first one is used to update the device cgroup and the second one to update the resources in the OCI spec. Signed-off-by: Julio Montes <julio.montes@intel.com> Signed-off-by: Peng Tao <bergwolf@hyper.sh>
121 lines
3.2 KiB
Go
121 lines
3.2 KiB
Go
// Copyright (c) 2020 Intel Corporation
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//
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// SPDX-License-Identifier: Apache-2.0
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//
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package cgroups
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import (
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"fmt"
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"os"
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"path/filepath"
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"regexp"
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"github.com/opencontainers/runc/libcontainer/configs"
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"github.com/opencontainers/runtime-spec/specs-go"
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"golang.org/x/sys/unix"
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)
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// prepend a kata specific string to oci cgroup path to
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// form a different cgroup path, thus cAdvisor couldn't
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// find kata containers cgroup path on host to prevent it
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// from grabbing the stats data.
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const CgroupKataPrefix = "kata"
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// DefaultCgroupPath runtime-determined location in the cgroups hierarchy.
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const DefaultCgroupPath = "/vc"
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func RenameCgroupPath(path string) (string, error) {
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if path == "" {
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return "", fmt.Errorf("Cgroup path is empty")
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}
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cgroupPathDir := filepath.Dir(path)
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cgroupPathName := fmt.Sprintf("%s_%s", CgroupKataPrefix, filepath.Base(path))
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return filepath.Join(cgroupPathDir, cgroupPathName), nil
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}
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// validCgroupPath returns a valid cgroup path.
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// see https://github.com/opencontainers/runtime-spec/blob/master/config-linux.md#cgroups-path
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func ValidCgroupPath(path string, systemdCgroup bool) (string, error) {
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if IsSystemdCgroup(path) {
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return path, nil
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}
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if systemdCgroup {
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return "", fmt.Errorf("malformed systemd path '%v': expected to be of form 'slice:prefix:name'", path)
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}
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// In the case of an absolute path (starting with /), the runtime MUST
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// take the path to be relative to the cgroups mount point.
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if filepath.IsAbs(path) {
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return RenameCgroupPath(filepath.Clean(path))
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}
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// In the case of a relative path (not starting with /), the runtime MAY
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// interpret the path relative to a runtime-determined location in the cgroups hierarchy.
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// clean up path and return a new path relative to DefaultCgroupPath
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return RenameCgroupPath(filepath.Join(DefaultCgroupPath, filepath.Clean("/"+path)))
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}
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func IsSystemdCgroup(cgroupPath string) bool {
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// systemd cgroup path: slice:prefix:name
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re := regexp.MustCompile(`([[:alnum:]]|\.)+:([[:alnum:]]|\.)+:([[:alnum:]]|\.)+`)
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found := re.FindStringIndex(cgroupPath)
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// if found string is equal to cgroupPath then
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// it's a correct systemd cgroup path.
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return found != nil && cgroupPath[found[0]:found[1]] == cgroupPath
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}
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func DeviceToCgroupDevice(device string) (*configs.Device, error) {
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var st unix.Stat_t
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linuxDevice := configs.Device{
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Allow: true,
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Permissions: "rwm",
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Path: device,
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}
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if err := unix.Stat(device, &st); err != nil {
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return nil, err
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}
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devType := st.Mode & unix.S_IFMT
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switch devType {
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case unix.S_IFCHR:
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linuxDevice.Type = 'c'
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case unix.S_IFBLK:
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linuxDevice.Type = 'b'
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default:
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return nil, fmt.Errorf("unsupported device type: %v", devType)
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}
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major := int64(unix.Major(st.Rdev))
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minor := int64(unix.Minor(st.Rdev))
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linuxDevice.Major = major
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linuxDevice.Minor = minor
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linuxDevice.Gid = st.Gid
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linuxDevice.Uid = st.Uid
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linuxDevice.FileMode = os.FileMode(st.Mode)
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return &linuxDevice, nil
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}
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func DeviceToLinuxDevice(device string) (specs.LinuxDeviceCgroup, error) {
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dev, err := DeviceToCgroupDevice(device)
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if err != nil {
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return specs.LinuxDeviceCgroup{}, err
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}
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return specs.LinuxDeviceCgroup{
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Allow: dev.Allow,
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Type: string(dev.Type),
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Major: &dev.Major,
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Minor: &dev.Minor,
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Access: dev.Permissions,
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}, nil
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}
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