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// -*- Mode: Go; indent-tabs-mode: t -*-
/*
* Copyright (C) 2016-2017 Canonical Ltd
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 3 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
package mount
import (
"fmt"
"os/exec"
"path/filepath"
"github.com/snapcore/snapd/dirs"
"github.com/snapcore/snapd/osutil"
"github.com/snapcore/snapd/snapdtool"
)
// mountNsPath returns path of the mount namespace file of a given snap
func mountNsPath(snapName string) string {
// NOTE: This value has to be synchronized with snap-confine
return filepath.Join(dirs.SnapRunNsDir, fmt.Sprintf("%s.mnt", snapName))
}
// Run an internal tool on a given snap namespace, if one exists.
func runNamespaceTool(toolName, snapName string) ([]byte, error) {
mntFile := mountNsPath(snapName)
if osutil.FileExists(mntFile) {
toolPath, err := snapdtool.InternalToolPath(toolName)
if err != nil {
return nil, err
}
cmd := exec.Command(toolPath, snapName)
output, err := cmd.CombinedOutput()
return output, err
}
return nil, nil
}
// Discard the mount namespace of a given snap.
func DiscardSnapNamespace(snapName string) error {
output, err := runNamespaceTool("snap-discard-ns", snapName)
if err != nil {
return fmt.Errorf("cannot discard preserved namespace of snap %q: %s", snapName, osutil.OutputErr(output, err))
}
return nil
}
// Update the mount namespace of a given snap.
func UpdateSnapNamespace(snapName string) error {
output, err := runNamespaceTool("snap-update-ns", snapName)
if err != nil {
return fmt.Errorf("cannot update preserved namespace of snap %q: %s", snapName, osutil.OutputErr(output, err))
}
return nil
}
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