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

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package wclayer
import (
"syscall"
"github.com/Microsoft/hcsshim/internal/hcserror"
"github.com/sirupsen/logrus"
)
// GetLayerMountPath will look for a mounted layer with the given path 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(path string) (string, error) {
title := "hcsshim::GetLayerMountPath "
logrus.Debugf(title+"path %s", path)
var mountPathLength uintptr
mountPathLength = 0
// Call the procedure itself.
logrus.Debugf("Calling proc (1)")
err := getLayerMountPath(&stdDriverInfo, path, &mountPathLength, nil)
if err != nil {
err = hcserror.Errorf(err, title, "(first call) path=%s", path)
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(&stdDriverInfo, path, &mountPathLength, &mountPathp[0])
if err != nil {
err = hcserror.Errorf(err, title, "(second call) path=%s", path)
logrus.Error(err)
return "", err
}
mountPath := syscall.UTF16ToString(mountPathp[0:])
logrus.Debugf(title+"succeeded path=%s mountPath=%s", path, mountPath)
return mountPath, nil
}