DockerCLI/vendor/github.com/Microsoft/hcsshim/getlayermountpath.go

56 lines
1.5 KiB
Go

package hcsshim
import (
"syscall"
"github.com/sirupsen/logrus"
)
// GetLayerMountPath will look for a mounted layer with the given id and return
// the path at which that layer can be accessed. This path may be a volume path
// if the layer is a mounted read-write layer, otherwise it is expected to be the
// folder path at which the layer is stored.
func GetLayerMountPath(info DriverInfo, id string) (string, error) {
title := "hcsshim::GetLayerMountPath "
logrus.Debugf(title+"Flavour %d ID %s", info.Flavour, id)
// Convert info to API calling convention
infop, err := convertDriverInfo(info)
if err != nil {
logrus.Error(err)
return "", err
}
var mountPathLength uintptr
mountPathLength = 0
// Call the procedure itself.
logrus.Debugf("Calling proc (1)")
err = getLayerMountPath(&infop, id, &mountPathLength, nil)
if err != nil {
err = makeErrorf(err, title, "(first call) id=%s flavour=%d", id, info.Flavour)
logrus.Error(err)
return "", err
}
// Allocate a mount path of the returned length.
if mountPathLength == 0 {
return "", nil
}
mountPathp := make([]uint16, mountPathLength)
mountPathp[0] = 0
// Call the procedure again
logrus.Debugf("Calling proc (2)")
err = getLayerMountPath(&infop, id, &mountPathLength, &mountPathp[0])
if err != nil {
err = makeErrorf(err, title, "(second call) id=%s flavour=%d", id, info.Flavour)
logrus.Error(err)
return "", err
}
path := syscall.UTF16ToString(mountPathp[0:])
logrus.Debugf(title+"succeeded flavour=%d id=%s path=%s", info.Flavour, id, path)
return path, nil
}