Raw block device passthrough support

vm/os_specifics.go

@@ -4,7 +4,11 @@ package vm
 
 import (
 	"os/exec"
+	"path/filepath"
+	"strings"
 	"syscall"
+
+	"github.com/pkg/errors"
 )
 
 func prepareVMCmd(cmd *exec.Cmd) {
@@ -17,3 +21,26 @@ func prepareVMCmd(cmd *exec.Cmd) {
 func terminateProcess(pid int) error {
 	return syscall.Kill(-pid, syscall.SIGTERM)
 }
+
+// This is never used except for a band-aid that would check
+// that there are no double-mounts.
+func checkDeviceSeemsMounted(devPathPrefix string) (bool, error) {
+	absDevPathPrefix, err := filepath.Abs(devPathPrefix)
+	if err != nil {
+		return false, errors.Wrap(err, "get abs path")
+	}
+
+	mounts, err := exec.Command("mount").Output()
+	if err != nil {
+		return false, errors.Wrap(err, "run mount command")
+	}
+
+	for _, line := range strings.Split(string(mounts), "\n") {
+		// I know, I know, this is a rare band-aid.
+		if strings.HasPrefix(line, devPathPrefix) || strings.HasPrefix(line, absDevPathPrefix) {
+			return true, nil
+		}
+	}
+
+	return false, nil
+}