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Merge pull request #212 from cyphar/devices
devices: move libcontainer/devices to moby/sys
2 parents 469a746 + 1b36f79 commit bdb4ad6

6 files changed

Lines changed: 272 additions & 1 deletion

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‎Makefile‎

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PACKAGES ?= atomicwriter capability mountinfo mount reexec sequential signal symlink user userns
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PACKAGES ?= atomicwriter capability devices mountinfo mount reexec sequential signal symlink user userns
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CROSS ?= linux/arm linux/arm64 linux/ppc64le linux/s390x \
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freebsd/amd64 openbsd/amd64 darwin/amd64 darwin/arm64 windows/amd64
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SUDO ?= sudo -n

‎devices/device_unix.go‎

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//go:build !windows
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// SPDX-License-Identifier: Apache-2.0
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/*
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* Copyright (C) 2015-2026 Open Containers Initiative Contributors
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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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// This code originally comes from runc and was taken from this tree:
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// <https://github.com/opencontainers/runc/tree/v1.4.0/libcontainer/devices>.
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package devices
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import (
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"errors"
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"os"
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"path/filepath"
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"github.com/opencontainers/cgroups/devices/config"
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"golang.org/x/sys/unix"
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)
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// ErrNotADevice denotes that a file is not a valid linux device.
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var ErrNotADevice = errors.New("not a device node")
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// Testing dependencies
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var (
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unixLstat = unix.Lstat
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osReadDir = os.ReadDir
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)
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// DeviceFromPath takes the path to a device and its cgroup_permissions (which
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// cannot be easily queried) to look up the information about a linux device
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// and returns that information as a Device struct.
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func DeviceFromPath(path, permissions string) (*config.Device, error) {
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var stat unix.Stat_t
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err := unixLstat(path, &stat)
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if err != nil {
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return nil, err
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}
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var (
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devType config.Type
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mode = stat.Mode
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devNumber = uint64(stat.Rdev) //nolint:unconvert // Rdev is uint32 on e.g. MIPS.
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major = unix.Major(devNumber)
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minor = unix.Minor(devNumber)
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)
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switch mode & unix.S_IFMT {
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case unix.S_IFBLK:
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devType = config.BlockDevice
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case unix.S_IFCHR:
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devType = config.CharDevice
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case unix.S_IFIFO:
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devType = config.FifoDevice
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default:
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return nil, ErrNotADevice
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}
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return &config.Device{
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Rule: config.Rule{
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Type: devType,
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Major: int64(major),
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Minor: int64(minor),
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Permissions: config.Permissions(permissions),
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},
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Path: path,
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FileMode: os.FileMode(mode &^ unix.S_IFMT),
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Uid: stat.Uid,
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Gid: stat.Gid,
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}, nil
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}
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// HostDevices returns all devices that can be found under /dev directory.
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func HostDevices() ([]*config.Device, error) {
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return GetDevices("/dev")
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}
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// GetDevices recursively traverses a directory specified by path
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// and returns all devices found there.
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func GetDevices(path string) ([]*config.Device, error) {
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files, err := osReadDir(path)
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if err != nil {
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return nil, err
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}
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var out []*config.Device
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for _, f := range files {
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switch {
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case f.IsDir():
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switch f.Name() {
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// ".lxc" & ".lxd-mounts" added to address https://github.com/lxc/lxd/issues/2825
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// ".udev" added to address https://github.com/opencontainers/runc/issues/2093
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case "pts", "shm", "fd", "mqueue", ".lxc", ".lxd-mounts", ".udev":
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continue
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default:
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sub, err := GetDevices(filepath.Join(path, f.Name()))
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if err != nil {
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return nil, err
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}
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out = append(out, sub...)
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continue
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}
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case f.Name() == "console":
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continue
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}
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device, err := DeviceFromPath(filepath.Join(path, f.Name()), "rwm")
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if err != nil {
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if errors.Is(err, ErrNotADevice) {
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continue
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}
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if errors.Is(err, os.ErrNotExist) {
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continue
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}
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return nil, err
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}
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if device.Type == config.FifoDevice {
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continue
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}
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out = append(out, device)
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}
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return out, nil
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}

‎devices/device_unix_test.go‎

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//go:build !windows
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// SPDX-License-Identifier: Apache-2.0
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/*
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* Copyright (C) 2015-2026 Open Containers Initiative Contributors
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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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// This code originally comes from runc and was taken from this tree:
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// <https://github.com/opencontainers/runc/tree/v1.4.0/libcontainer/devices>.
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package devices
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import (
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"errors"
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"io/fs"
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"os"
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"runtime"
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"testing"
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"github.com/opencontainers/cgroups/devices/config"
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"golang.org/x/sys/unix"
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)
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func cleanupTest() {
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unixLstat = unix.Lstat
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osReadDir = os.ReadDir
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}
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func TestDeviceFromPathLstatFailure(t *testing.T) {
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testError := errors.New("test error")
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// Override unix.Lstat to inject error.
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unixLstat = func(path string, stat *unix.Stat_t) error {
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return testError
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}
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defer cleanupTest()
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_, err := DeviceFromPath("", "")
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if !errors.Is(err, testError) {
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t.Fatalf("Unexpected error %v, expected %v", err, testError)
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}
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}
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func TestHostDevicesIoutilReadDirFailure(t *testing.T) {
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testError := errors.New("test error")
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// Override os.ReadDir to inject error.
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osReadDir = func(dirname string) ([]fs.DirEntry, error) {
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return nil, testError
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}
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defer cleanupTest()
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_, err := HostDevices()
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if !errors.Is(err, testError) {
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t.Fatalf("Unexpected error %v, expected %v", err, testError)
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}
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}
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func TestHostDevicesIoutilReadDirDeepFailure(t *testing.T) {
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testError := errors.New("test error")
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called := false
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// Override os.ReadDir to inject error after the first call.
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osReadDir = func(dirname string) ([]fs.DirEntry, error) {
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if called {
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return nil, testError
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}
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called = true
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// Provoke a second call.
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fi, err := os.Stat("/tmp")
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if err != nil {
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t.Fatalf("Unexpected error %v", err)
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}
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return []fs.DirEntry{fs.FileInfoToDirEntry(fi)}, nil
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}
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defer cleanupTest()
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_, err := HostDevices()
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if !errors.Is(err, testError) {
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t.Fatalf("Unexpected error %v, expected %v", err, testError)
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}
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}
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func TestHostDevicesAllValid(t *testing.T) {
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devices, err := HostDevices()
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if err != nil {
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t.Fatalf("failed to get host devices: %v", err)
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}
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for _, device := range devices {
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// Devices can't have major number 0 on Linux.
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if device.Major == 0 {
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logFn := t.Logf
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if runtime.GOOS == "linux" {
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logFn = t.Errorf
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}
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logFn("device entry %+v has zero major number", device)
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}
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switch device.Type {
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case config.BlockDevice, config.CharDevice:
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case config.FifoDevice:
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t.Logf("fifo devices shouldn't show up from HostDevices")
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fallthrough
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default:
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t.Errorf("device entry %+v has unexpected type %v", device, device.Type)
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}
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}
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}

‎devices/doc.go‎

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// Package devices provides some helper functions for constructing device
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// configurations for runc. These are exclusively used by higher-level runtimes
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// that need to configure runc's device list based on existing devices.
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package devices

‎devices/go.mod‎

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module github.com/moby/sys/devices
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go 1.24
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require (
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github.com/opencontainers/cgroups v0.0.6
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golang.org/x/sys v0.30.0
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)

‎devices/go.sum‎

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github.com/opencontainers/cgroups v0.0.6 h1:tfZFWTIIGaUUFImTyuTg+Mr5x8XRiSdZESgEBW7UxuI=
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github.com/opencontainers/cgroups v0.0.6/go.mod h1:oWVzJsKK0gG9SCRBfTpnn16WcGEqDI8PAcpMGbqWxcs=
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golang.org/x/sys v0.30.0 h1:QjkSwP/36a20jFYWkSue1YwXzLmsV5Gfq7Eiy72C1uc=
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golang.org/x/sys v0.30.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=

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