podman run cannot mount volume named with single character on windows

[axel7083]

Issue Description

When trying to mount a volume which has a name which is a single character on windows, ( e.g. a, b, c etc.) an error is throwed.

Deep dive

On windows, the parsing of the volume argument is a bit tricky.

1. It starts here, in our example volumeFlag = ["a:/mnt/home"]

podman/pkg/specgenutil/volumes.go

Line 46 in 806722b

volumeMounts, volumeVolumes, overlayVolumes, err := specgen.GenVolumeMounts(volumeFlag)

2. For each volume flag, we try to split it in 3 part [[SOURCE-VOLUME|HOST-DIR:]CONTAINER-DIR[:OPTIONS]]

podman/pkg/specgen/volumes.go

Line 208 in 693ae0e

func SplitVolumeString(vol string) []string {

3. But windows... amazing windows, absolute path have a drive letter (E.g. C:/hello/world) and the following code is responsible of checking if it is an absolute path

podman/pkg/specgen/volumes.go

Lines 220 to 224 in 693ae0e

	if hasWinDriveScheme(vol, n) {
	first := parts[0] + ":" + parts[1]
	parts = parts[1:]
	parts[0] = first
	}

4. Deep dive into hasWinDriveScheme

podman/pkg/specgen/winpath.go

Lines 14 to 21 in a46f798

	func hasWinDriveScheme(path string, start int) bool {
	if len(path) < start+2 || path[start+1] != ':' {
	return false
	}
	drive := rune(path[start])
	return drive < unicode.MaxASCII && unicode.IsLetter(drive)
	}

In our example, path = "a:/mnt/home", start = 0.

• len(path) < start+2 = false
• path[start+1] != ':' = false (problematic, it is confusing the colon separating the driver letter with the separator of the volume and container path

The last part is checking if the letter is a driver letter accepted value.

Steps to reproduce the issue

Run the following on windows

$: podman create volume a
a
$: podman run -v a:/mnt/ hello-world
Error: invalid container path "a:/mnt", must be an absolute path

Describe the results you received

On windows, I am getting the following error

Error: invalid container path "a:/mnt", must be an absolute path

Describe the results you expected

Volume to be mounted.

podman info output

host:
  arch: amd64
  buildahVersion: 1.38.0
  cgroupControllers:
  - cpuset
  - cpu
  - cpuacct
  - blkio
  - memory
  - devices
  - freezer
  - net_cls
  - perf_event
  - net_prio
  - hugetlb
  - pids
  - rdma
  - misc
  cgroupManager: cgroupfs
  cgroupVersion: v1
  conmon:
    package: conmon-2.1.12-2.fc40.x86_64
    path: /usr/bin/conmon
    version: 'conmon version 2.1.12, commit: '
  cpuUtilization:
    idlePercent: 99.4
    systemPercent: 0.39
    userPercent: 0.21
  cpus: 12
  databaseBackend: sqlite
  distribution:
    distribution: fedora
    variant: container
    version: "40"
  eventLogger: journald
  freeLocks: 2034
  hostname: Axel-Fix
  idMappings:
    gidmap: null
    uidmap: null
  kernel: 5.15.167.4-microsoft-standard-WSL2
  linkmode: dynamic
  logDriver: journald
  memFree: 23875559424
  memTotal: 25204797440
  networkBackend: netavark
  networkBackendInfo:
    backend: netavark
    dns:
      package: aardvark-dns-1.13.1-1.fc40.x86_64
      path: /usr/libexec/podman/aardvark-dns
      version: aardvark-dns 1.13.1
    package: netavark-1.13.1-1.fc40.x86_64
    path: /usr/libexec/podman/netavark
    version: netavark 1.13.1
  ociRuntime:
    name: crun
    package: crun-1.19.1-1.fc40.x86_64
    path: /usr/bin/crun
    version: |-
      crun version 1.19.1
      commit: 3e32a70c93f5aa5fea69b50256cca7fd4aa23c80
      rundir: /run/crun
      spec: 1.0.0
      +SYSTEMD +SELINUX +APPARMOR +CAP +SECCOMP +EBPF +CRIU +LIBKRUN +WASM:wasmedge +YAJL
  os: linux
  pasta:
    executable: /usr/bin/pasta
    package: passt-0^20241211.g09478d5-1.fc40.x86_64
    version: |
      pasta 0^20241211.g09478d5-1.fc40.x86_64
      Copyright Red Hat
      GNU General Public License, version 2 or later
        <https://www.gnu.org/licenses/old-licenses/gpl-2.0.html>
      This is free software: you are free to change and redistribute it.
      There is NO WARRANTY, to the extent permitted by law.
  remoteSocket:
    exists: true
    path: unix:///run/podman/podman.sock
  rootlessNetworkCmd: pasta
  security:
    apparmorEnabled: false
    capabilities: CAP_CHOWN,CAP_DAC_OVERRIDE,CAP_FOWNER,CAP_FSETID,CAP_KILL,CAP_NET_BIND_SERVICE,CAP_SETFCAP,CAP_SETGID,CAP_SETPCAP,CAP_SETUID,CAP_SYS_CHROOT
    rootless: false
    seccompEnabled: true
    seccompProfilePath: /usr/share/containers/seccomp.json
    selinuxEnabled: false
  serviceIsRemote: true
  slirp4netns:
    executable: ""
    package: ""
    version: ""
  swapFree: 6442450944
  swapTotal: 6442450944
  uptime: 0h 9m 49.00s
  variant: ""
plugins:
  authorization: null
  log:
  - k8s-file
  - none
  - passthrough
  - journald
  network:
  - bridge
  - macvlan
  - ipvlan
  volume:
  - local
registries:
  search:
  - docker.io
store:
  configFile: /usr/share/containers/storage.conf
  containerStore:
    number: 5
    paused: 0
    running: 0
    stopped: 5
  graphDriverName: overlay
  graphOptions:
    overlay.imagestore: /usr/lib/containers/storage
    overlay.mountopt: nodev,metacopy=on
  graphRoot: /var/lib/containers/storage
  graphRootAllocated: 1081101176832
  graphRootUsed: 19998404608
  graphStatus:
    Backing Filesystem: extfs
    Native Overlay Diff: "false"
    Supports d_type: "true"
    Supports shifting: "false"
    Supports volatile: "true"
    Using metacopy: "true"
  imageCopyTmpDir: /var/tmp
  imageStore:
    number: 110
  runRoot: /run/containers/storage
  transientStore: false
  volumePath: /var/lib/containers/storage/volumes
version:
  APIVersion: 5.3.1
  Built: 1732147200
  BuiltTime: Thu Nov 21 01:00:00 2024
  GitCommit: ""
  GoVersion: go1.22.7
  Os: linux
  OsArch: linux/amd64
  Version: 5.3.1

Podman in a container

No

Privileged Or Rootless

None

Upstream Latest Release

Yes

Additional environment details

N/A

Additional information

N/A

[l0rd]

Nice catch @axel7083. A small note: in the description, you use the command podman create volume, but you probably meant podman volume create.

Are you going to submit a PR for this? Considering the analysis you have already done, it should not be hard. If you do, you want to start by adding a new test in machine e2e volumes.