This allows non-privileged users to use containerd. This is part of a larger track of work integrating containerd into Cloudfoundry's garden with support for rootless. [#156343575] Signed-off-by: Claudia Beresford <cberesford@pivotal.io>
		
			
				
	
	
		
			74 lines
		
	
	
		
			2.3 KiB
		
	
	
	
		
			Go
		
	
	
	
	
	
			
		
		
	
	
			74 lines
		
	
	
		
			2.3 KiB
		
	
	
	
		
			Go
		
	
	
	
	
	
/*
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   Copyright The containerd Authors.
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   Licensed under the Apache License, Version 2.0 (the "License");
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   you may not use this file except in compliance with the License.
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   You may obtain a copy of the License at
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       http://www.apache.org/licenses/LICENSE-2.0
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   Unless required by applicable law or agreed to in writing, software
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   distributed under the License is distributed on an "AS IS" BASIS,
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   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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   See the License for the specific language governing permissions and
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   limitations under the License.
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*/
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package mount
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import (
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	"context"
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	"io/ioutil"
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	"os"
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	"github.com/containerd/containerd/log"
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	"github.com/pkg/errors"
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)
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var tempMountLocation = getTempDir()
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// WithTempMount mounts the provided mounts to a temp dir, and pass the temp dir to f.
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// The mounts are valid during the call to the f.
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// Finally we will unmount and remove the temp dir regardless of the result of f.
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func WithTempMount(ctx context.Context, mounts []Mount, f func(root string) error) (err error) {
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	root, uerr := ioutil.TempDir(tempMountLocation, "containerd-mount")
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	if uerr != nil {
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		return errors.Wrapf(uerr, "failed to create temp dir")
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	}
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	// We use Remove here instead of RemoveAll.
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	// The RemoveAll will delete the temp dir and all children it contains.
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	// When the Unmount fails, RemoveAll will incorrectly delete data from
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	// the mounted dir. However, if we use Remove, even though we won't
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	// successfully delete the temp dir and it may leak, we won't loss data
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	// from the mounted dir.
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	// For details, please refer to #1868 #1785.
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	defer func() {
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		if uerr = os.Remove(root); uerr != nil {
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			log.G(ctx).WithError(uerr).WithField("dir", root).Errorf("failed to remove mount temp dir")
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		}
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	}()
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	// We should do defer first, if not we will not do Unmount when only a part of Mounts are failed.
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	defer func() {
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		if uerr = UnmountAll(root, 0); uerr != nil {
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			uerr = errors.Wrapf(uerr, "failed to unmount %s", root)
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			if err == nil {
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				err = uerr
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			} else {
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				err = errors.Wrap(err, uerr.Error())
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			}
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		}
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	}()
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	if uerr = All(mounts, root); uerr != nil {
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		return errors.Wrapf(uerr, "failed to mount %s", root)
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	}
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	return errors.Wrapf(f(root), "mount callback failed on %s", root)
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}
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func getTempDir() string {
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	if xdg := os.Getenv("XDG_RUNTIME_DIR"); xdg != "" {
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		return xdg
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	}
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	return os.TempDir()
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}
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