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Ensure that filemode is set for device nodes #275

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22 changes: 14 additions & 8 deletions pkg/cdi/container-edits_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -17,6 +17,7 @@
package cdi

import (
"os"
"runtime"
"testing"

Expand Down Expand Up @@ -306,6 +307,9 @@ func TestValidateContainerEdits(t *testing.T) {
func TestApplyContainerEdits(t *testing.T) {
nullDeviceMajor := int64(1)
nullDeviceMinor := int64(3)

mode := uint32(0666)
nullDeviceFileMode := (*os.FileMode)(&mode)
if runtime.GOOS == "darwin" {
nullDeviceMajor = 3
nullDeviceMinor = 2
Expand Down Expand Up @@ -352,10 +356,11 @@ func TestApplyContainerEdits(t *testing.T) {
Linux: &oci.Linux{
Devices: []oci.LinuxDevice{
{
Path: "/dev/null",
Type: "c",
Major: nullDeviceMajor,
Minor: nullDeviceMinor,
Path: "/dev/null",
Type: "c",
Major: nullDeviceMajor,
Minor: nullDeviceMinor,
FileMode: nullDeviceFileMode,
},
},
Resources: &oci.LinuxResources{
Expand Down Expand Up @@ -395,10 +400,11 @@ func TestApplyContainerEdits(t *testing.T) {
Linux: &oci.Linux{
Devices: []oci.LinuxDevice{
{
Path: "/dev/null",
Type: "c",
Major: nullDeviceMajor,
Minor: nullDeviceMinor,
Path: "/dev/null",
Type: "c",
Major: nullDeviceMajor,
Minor: nullDeviceMinor,
FileMode: nullDeviceFileMode,
},
},
Resources: &oci.LinuxResources{
Expand Down
52 changes: 41 additions & 11 deletions pkg/cdi/container-edits_unix.go
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Original file line number Diff line number Diff line change
Expand Up @@ -21,6 +21,7 @@ package cdi
import (
"errors"
"fmt"
"os"

"golang.org/x/sys/unix"
)
Expand All @@ -31,16 +32,28 @@ const (
fifoDevice = "p"
)

type deviceInfo struct {
// cgroup properties
deviceType string
major int64
minor int64

// device node properties
fileMode os.FileMode
}

// deviceInfoFromPath takes the path to a device and returns its type,
// major and minor device numbers.
//
// It was adapted from https://github.com/opencontainers/runc/blob/v1.1.9/libcontainer/devices/device_unix.go#L30-L69
func deviceInfoFromPath(path string) (devType string, major, minor int64, _ error) {
func deviceInfoFromPath(path string) (*deviceInfo, error) {
var stat unix.Stat_t
err := unix.Lstat(path, &stat)
if err != nil {
return "", 0, 0, err
return nil, err
}

var devType string
switch stat.Mode & unix.S_IFMT {
case unix.S_IFBLK:
devType = blockDevice
Expand All @@ -49,10 +62,18 @@ func deviceInfoFromPath(path string) (devType string, major, minor int64, _ erro
case unix.S_IFIFO:
devType = fifoDevice
default:
return "", 0, 0, errors.New("not a device node")
return nil, errors.New("not a device node")
}
devNumber := uint64(stat.Rdev) //nolint:unconvert // Rdev is uint32 on e.g. MIPS.
return devType, int64(unix.Major(devNumber)), int64(unix.Minor(devNumber)), nil

di := deviceInfo{
deviceType: devType,
major: int64(unix.Major(devNumber)),
minor: int64(unix.Minor(devNumber)),
fileMode: os.FileMode(stat.Mode &^ unix.S_IFMT),
}

return &di, nil
}

// fillMissingInfo fills in missing mandatory attributes from the host device.
Expand All @@ -65,22 +86,31 @@ func (d *DeviceNode) fillMissingInfo() error {
return nil
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Should we also set d.FileMode here?

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What would you set it to in this case?

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The same as below?

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This logic is an early return meaning that we don't query the device node. I can make things a bit more consistent though. Let me see what I can come up with.

}

deviceType, major, minor, err := deviceInfoFromPath(d.HostPath)
di, err := deviceInfoFromPath(d.HostPath)
if err != nil {
return fmt.Errorf("failed to stat CDI host device %q: %w", d.HostPath, err)
}

if d.Type == "" {
d.Type = deviceType
d.Type = di.deviceType
} else {
if d.Type != deviceType {
if d.Type != di.deviceType {
return fmt.Errorf("CDI device (%q, %q), host type mismatch (%s, %s)",
d.Path, d.HostPath, d.Type, deviceType)
d.Path, d.HostPath, d.Type, di.deviceType)
}
}
if d.Major == 0 && d.Type != "p" {
d.Major = major
d.Minor = minor

if d.FileMode == nil {
d.FileMode = &di.fileMode
}

if d.Type == "p" {
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Suggested change
if d.Type == "p" {
if d.Type == fifoDevice {

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We use "p" elsewhere in this function. I don't mind changing this to a constant, but would do so consistently across this function.

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Yes, please do.

return nil
}

if d.Major == 0 {
d.Major = di.major
d.Minor = di.minor
}

return nil
Expand Down