Windows check mount support

vm/os_specifics.go

@@ -25,6 +25,7 @@ func terminateProcess(pid int) error {
 // This is never used except for a band-aid that would check
 // that there are no double-mounts.
 func checkDeviceSeemsMounted(devPathPrefix string) (bool, error) {
+	// Quite a bit hacky implementation, but it's to be used as a failsafe band-aid anyway.
 	absDevPathPrefix, err := filepath.Abs(devPathPrefix)
 	if err != nil {
 		return false, errors.Wrap(err, "get abs path")

vm/os_specifics_windows.go

@@ -5,7 +5,11 @@ package vm
 import (
 	"fmt"
 	"os/exec"
+	"regexp"
+	"strings"
 	"syscall"
+
+	"github.com/pkg/errors"
 )
 
 func prepareVMCmd(cmd *exec.Cmd) {
@@ -19,7 +23,27 @@ func terminateProcess(pid int) error {
 	return exec.Command("TASKKILL", "/T", "/F", "/PID", fmt.Sprint(pid)).Run()
 }
 
+var physicalDriveRegexp = regexp.MustCompile(`PhysicalDrive(\d+)`)
+
+// This is never used except for a band-aid that would check
+// that there are no double-mounts.
 func checkDeviceSeemsMounted(path string) (bool, error) {
-	// We do not have mount checks on Windows.
+	// Quite a bit hacky implementation, but it's to be used as a failsafe band-aid anyway.
-	return false, nil
+	matches := physicalDriveRegexp.FindAllStringSubmatch(path, 1)
+	if len(matches) == 0 {
+		return false, fmt.Errorf("bad device path '%v'", path)
+	}
+
+	match := matches[0]
+
+	if want, have := 2, len(match); want != have {
+		return false, fmt.Errorf("bad match items length: want %v, have %v (%v)", want, have, match)
+	}
+
+	out, err := exec.Command("wmic", "path", "Win32_LogicalDiskToPartition", "get", "Antecedent").Output()
+	if err != nil {
+		return false, errors.Wrap(err, "exec wmic cmd")
+	}
+
+	return strings.Contains(string(out), fmt.Sprintf("Disk #%v", match[1])), nil
 }

vm/vm.go

@@ -222,7 +222,6 @@ func NewVM(logger *slog.Logger, cfg VMConfig) (*VM, error) {
 	for _, dev := range cfg.PassthroughConfig.Block {
 		// It's always a user's responsibility to ensure that no drives are mounted
 		// in both host and guest system. This should serve as the last resort.
-		// TODO: Windows support.
 		{
 			seemsMounted, err := checkDeviceSeemsMounted(dev.Path)
 			if err != nil {