public/lib/svc/go/src/svc/svcfs/svcfs.go

// Copyright 2017 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// Package svcfs implements the Fuchsia service namespace.
package svcfs

import (
	"strings"

	"syscall/zx"
	"syscall/zx/fidl"
	"syscall/zx/io"
)

type Provider func(name string, c zx.Channel)

type Namespace struct {
	Provider Provider
	service  io.DirectoryService
}

func (n *Namespace) Clone(flags uint32, req io.NodeInterfaceRequest) error {
	c := ((fidl.InterfaceRequest)(req)).Channel
	if err := n.Serve(c); err != nil {
		c.Close()
		return err
	}
	if flags&io.OpenFlagDescribe != 0 {
		pxy := io.NodeEventProxy(fidl.ChannelProxy{c})
		info := &io.NodeInfo{NodeInfoTag: io.NodeInfoService}
		return pxy.OnOpen(int32(zx.ErrOk), info)
	}
	return nil
}

func (n *Namespace) Close() (int32, error) {
	return int32(zx.ErrNotSupported), nil
}

func (n *Namespace) ListInterfaces() ([]string, error) {
	return nil, nil
}

func (n *Namespace) Bind(iface string) error {
	return nil
}

func (n *Namespace) Describe() (io.NodeInfo, error) {
	return io.NodeInfo{NodeInfoTag: io.NodeInfoDirectory}, nil
}

func (n *Namespace) Sync() (int32, error) {
	return int32(zx.ErrNotSupported), nil
}

func (n *Namespace) GetAttr() (int32, io.NodeAttributes, error) {
	return int32(zx.ErrNotSupported), io.NodeAttributes{}, nil
}

func (n *Namespace) SetAttr(flags uint32, attributes io.NodeAttributes) (int32, error) {
	return int32(zx.ErrNotSupported), nil
}

func (n *Namespace) Ioctl(opcode uint32, maxOut uint64, handles []zx.Handle, in []uint8) (int32, []zx.Handle, []uint8, error) {
	return int32(zx.ErrNotSupported), nil, nil, nil
}

// Open opens a service and emits an OnOpen event when ready.
func (n *Namespace) Open(flags, _ uint32, path string, obj io.NodeInterfaceRequest) error {
	respond := func(status zx.Status) error {
		if flags&io.OpenFlagDescribe != 0 {
			info := &io.NodeInfo{NodeInfoTag: io.NodeInfoService}
			c := fidl.InterfaceRequest(obj).Channel
			pxy := io.NodeEventProxy(fidl.ChannelProxy{Channel: c})
			return pxy.OnOpen(int32(status), info)
		}
		return nil
	}

	if strings.IndexByte(path, '/') != -1 {
		// TODO(abarth): Implement path traversal.
		ir := fidl.InterfaceRequest(obj)
		ir.Close()
		return respond(zx.ErrNotSupported)
	}

	if path == "." || path == ".." {
		return respond(zx.ErrOk)
	}

	n.Provider(path, ((fidl.InterfaceRequest)(obj)).Channel)
	return respond(zx.ErrOk)
}

// Unlink implements io.Directory for Namespace.
func (n *Namespace) Unlink(path string) (int32, error) {
	return int32(zx.ErrNotSupported), nil
}

// ReadDirents implements io.Directory for Namespace.
func (n *Namespace) ReadDirents(maxOut uint64) (int32, []uint8, error) {
	return int32(zx.ErrNotSupported), nil, nil
}

// Rewind implements io.Directory for Namespace.
func (n *Namespace) Rewind() (int32, error) {
	return int32(zx.ErrNotSupported), nil
}

// GetToken implements io.Directory for Namespace.
func (n *Namespace) GetToken() (int32, zx.Handle, error) {
	// The returned handle is non-nullable, so this will currently cause
	// an internal failure.
	return int32(zx.ErrNotSupported), zx.HandleInvalid, nil
}

// Rename implements io.Directory for Namespace.
func (n *Namespace) Rename(src string, dstParentToken zx.Handle, dst string) (int32, error) {
	return int32(zx.ErrNotSupported), nil
}

// Link implements io.Directory for Namespace.
func (n *Namespace) Link(src string, dstParentToken zx.Handle, dst string) (int32, error) {
	return int32(zx.ErrNotSupported), nil
}

func (n *Namespace) Watch(mask uint32, options uint32, watcher zx.Channel) (int32, error) {
	watcher.Close()
	return int32(zx.ErrNotSupported), nil
}

func (n *Namespace) Serve(c zx.Channel) error {
	if _, err := n.service.Add(n, c, nil); err != nil {
		return err
	}
	h := zx.Handle(c)
	return h.SignalPeer(0, zx.SignalUser0)
}