github.com/adityamillind98/moby@v23.0.0-rc.4+incompatible/oci/devices_linux.go (about)

     1  package oci // import "github.com/docker/docker/oci"
     2  
     3  import (
     4  	"fmt"
     5  	"os"
     6  	"path/filepath"
     7  	"strings"
     8  
     9  	"github.com/opencontainers/runc/libcontainer/devices"
    10  	specs "github.com/opencontainers/runtime-spec/specs-go"
    11  	"golang.org/x/sys/unix"
    12  )
    13  
    14  // Device transforms a libcontainer devices.Device to a specs.LinuxDevice object.
    15  func Device(d *devices.Device) specs.LinuxDevice {
    16  	return specs.LinuxDevice{
    17  		Type:     string(d.Type),
    18  		Path:     d.Path,
    19  		Major:    d.Major,
    20  		Minor:    d.Minor,
    21  		FileMode: fmPtr(int64(d.FileMode &^ unix.S_IFMT)), // strip file type, as OCI spec only expects file-mode to be included
    22  		UID:      u32Ptr(int64(d.Uid)),
    23  		GID:      u32Ptr(int64(d.Gid)),
    24  	}
    25  }
    26  
    27  func deviceCgroup(d *devices.Device) specs.LinuxDeviceCgroup {
    28  	return specs.LinuxDeviceCgroup{
    29  		Allow:  true,
    30  		Type:   string(d.Type),
    31  		Major:  &d.Major,
    32  		Minor:  &d.Minor,
    33  		Access: string(d.Permissions),
    34  	}
    35  }
    36  
    37  // DevicesFromPath computes a list of devices and device permissions from paths (pathOnHost and pathInContainer) and cgroup permissions.
    38  func DevicesFromPath(pathOnHost, pathInContainer, cgroupPermissions string) (devs []specs.LinuxDevice, devPermissions []specs.LinuxDeviceCgroup, err error) {
    39  	resolvedPathOnHost := pathOnHost
    40  
    41  	// check if it is a symbolic link
    42  	if src, e := os.Lstat(pathOnHost); e == nil && src.Mode()&os.ModeSymlink == os.ModeSymlink {
    43  		if linkedPathOnHost, e := filepath.EvalSymlinks(pathOnHost); e == nil {
    44  			resolvedPathOnHost = linkedPathOnHost
    45  		}
    46  	}
    47  
    48  	device, err := devices.DeviceFromPath(resolvedPathOnHost, cgroupPermissions)
    49  	// if there was no error, return the device
    50  	if err == nil {
    51  		device.Path = pathInContainer
    52  		return append(devs, Device(device)), append(devPermissions, deviceCgroup(device)), nil
    53  	}
    54  
    55  	// if the device is not a device node
    56  	// try to see if it's a directory holding many devices
    57  	if err == devices.ErrNotADevice {
    58  		// check if it is a directory
    59  		if src, e := os.Stat(resolvedPathOnHost); e == nil && src.IsDir() {
    60  			// mount the internal devices recursively
    61  			// TODO check if additional errors should be handled or logged
    62  			_ = filepath.Walk(resolvedPathOnHost, func(dpath string, f os.FileInfo, _ error) error {
    63  				childDevice, e := devices.DeviceFromPath(dpath, cgroupPermissions)
    64  				if e != nil {
    65  					// ignore the device
    66  					return nil
    67  				}
    68  
    69  				// add the device to userSpecified devices
    70  				childDevice.Path = strings.Replace(dpath, resolvedPathOnHost, pathInContainer, 1)
    71  				devs = append(devs, Device(childDevice))
    72  				devPermissions = append(devPermissions, deviceCgroup(childDevice))
    73  
    74  				return nil
    75  			})
    76  		}
    77  	}
    78  
    79  	if len(devs) > 0 {
    80  		return devs, devPermissions, nil
    81  	}
    82  
    83  	return devs, devPermissions, fmt.Errorf("error gathering device information while adding custom device %q: %s", pathOnHost, err)
    84  }