moby/oci/devices_linux.go

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package oci
import (
"fmt"
"os"
"path/filepath"
"strings"
"github.com/opencontainers/runc/libcontainer/configs"
"github.com/opencontainers/runc/libcontainer/devices"
specs "github.com/opencontainers/runtime-spec/specs-go"
)
// Device transforms a libcontainer configs.Device to a specs.Device object.
func Device(d *configs.Device) specs.Device {
return specs.Device{
Type: string(d.Type),
Path: d.Path,
Major: d.Major,
Minor: d.Minor,
FileMode: fmPtr(int64(d.FileMode)),
UID: u32Ptr(int64(d.Uid)),
GID: u32Ptr(int64(d.Gid)),
}
}
func deviceCgroup(d *configs.Device) specs.DeviceCgroup {
t := string(d.Type)
return specs.DeviceCgroup{
Allow: true,
Type: &t,
Major: &d.Major,
Minor: &d.Minor,
Access: &d.Permissions,
}
}
// DevicesFromPath computes a list of devices and device permissions from paths (pathOnHost and pathInContainer) and cgroup permissions.
func DevicesFromPath(pathOnHost, pathInContainer, cgroupPermissions string) (devs []specs.Device, devPermissions []specs.DeviceCgroup, err error) {
resolvedPathOnHost := pathOnHost
// check if it is a symbolic link
if src, e := os.Lstat(pathOnHost); e == nil && src.Mode()&os.ModeSymlink == os.ModeSymlink {
if linkedPathOnHost, e := filepath.EvalSymlinks(pathOnHost); e == nil {
resolvedPathOnHost = linkedPathOnHost
}
}
device, err := devices.DeviceFromPath(resolvedPathOnHost, cgroupPermissions)
// if there was no error, return the device
if err == nil {
device.Path = pathInContainer
return append(devs, Device(device)), append(devPermissions, deviceCgroup(device)), nil
}
// if the device is not a device node
// try to see if it's a directory holding many devices
if err == devices.ErrNotADevice {
// check if it is a directory
if src, e := os.Stat(resolvedPathOnHost); e == nil && src.IsDir() {
// mount the internal devices recursively
filepath.Walk(resolvedPathOnHost, func(dpath string, f os.FileInfo, e error) error {
childDevice, e := devices.DeviceFromPath(dpath, cgroupPermissions)
if e != nil {
// ignore the device
return nil
}
// add the device to userSpecified devices
childDevice.Path = strings.Replace(dpath, resolvedPathOnHost, pathInContainer, 1)
devs = append(devs, Device(childDevice))
devPermissions = append(devPermissions, deviceCgroup(childDevice))
return nil
})
}
}
if len(devs) > 0 {
return devs, devPermissions, nil
}
return devs, devPermissions, fmt.Errorf("error gathering device information while adding custom device %q: %s", pathOnHost, err)
}