143 lines
4.1 KiB
Go
143 lines
4.1 KiB
Go
// Copyright 2015 Google Inc. All Rights Reserved.
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//
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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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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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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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package fuse
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import (
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"errors"
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bazilfuse "bazil.org/fuse"
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"golang.org/x/net/context"
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)
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// A struct representing the status of a mount operation, with methods for
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// waiting on the mount to complete, waiting for unmounting, and causing
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// unmounting.
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type MountedFileSystem struct {
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dir string
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// The result to return from WaitForReady. Not valid until the channel is
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// closed.
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readyStatus error
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readyStatusAvailable chan struct{}
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// The result to return from Join. Not valid until the channel is closed.
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joinStatus error
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joinStatusAvailable chan struct{}
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}
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// Return the directory on which the file system is mounted (or where we
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// attempted to mount it.)
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func (mfs *MountedFileSystem) Dir() string {
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return mfs.dir
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}
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// Wait until the mount point is ready to be used. After a successful return
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// from this function, the contents of the mounted file system should be
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// visible in the directory supplied to NewMountPoint. May be called multiple
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// times.
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func (mfs *MountedFileSystem) WaitForReady(ctx context.Context) error {
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select {
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case <-mfs.readyStatusAvailable:
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return mfs.readyStatus
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case <-ctx.Done():
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return ctx.Err()
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}
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}
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// Block until a mounted file system has been unmounted. The return value will
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// be non-nil if anything unexpected happened while serving. May be called
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// multiple times. Must not be called unless WaitForReady has returned nil.
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func (mfs *MountedFileSystem) Join(ctx context.Context) error {
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select {
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case <-mfs.joinStatusAvailable:
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return mfs.joinStatus
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case <-ctx.Done():
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return ctx.Err()
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}
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}
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// Attempt to unmount the file system. Use Join to wait for it to actually be
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// unmounted. You must first call WaitForReady to ensure there is no race with
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// mounting.
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func (mfs *MountedFileSystem) Unmount() error {
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return bazilfuse.Unmount(mfs.dir)
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}
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// Runs in the background.
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func (mfs *MountedFileSystem) mountAndServe(
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server *server,
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options []bazilfuse.MountOption) {
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logger := getLogger()
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// Open a FUSE connection.
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logger.Println("Opening a FUSE connection.")
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c, err := bazilfuse.Mount(mfs.dir, options...)
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if err != nil {
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mfs.readyStatus = errors.New("bazilfuse.Mount: " + err.Error())
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close(mfs.readyStatusAvailable)
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return
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}
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defer c.Close()
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// Start a goroutine that will notify the MountedFileSystem object when the
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// connection says it is ready (or it fails to become ready).
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go func() {
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logger.Println("Waiting for the FUSE connection to be ready.")
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<-c.Ready
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logger.Println("The FUSE connection is ready.")
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mfs.readyStatus = c.MountError
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close(mfs.readyStatusAvailable)
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}()
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// Serve the connection using the file system object.
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logger.Println("Serving the FUSE connection.")
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if err := server.Serve(c); err != nil {
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mfs.joinStatus = errors.New("Serve: " + err.Error())
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close(mfs.joinStatusAvailable)
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return
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}
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// Signal that everything is okay.
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close(mfs.joinStatusAvailable)
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}
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// Attempt to mount the supplied file system on the given directory.
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// mfs.WaitForReady() must be called to find out whether the mount was
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// successful.
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func Mount(
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dir string,
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fs FileSystem,
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options ...bazilfuse.MountOption) (mfs *MountedFileSystem, err error) {
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// Create a server object.
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server, err := newServer(fs)
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if err != nil {
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return
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}
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// Initialize the struct.
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mfs = &MountedFileSystem{
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dir: dir,
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readyStatusAvailable: make(chan struct{}),
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joinStatusAvailable: make(chan struct{}),
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}
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// Mount in the background.
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go mfs.mountAndServe(server, options)
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return
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}
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