src/syscall/zx/fdio/mxc/mxc_cgo.go

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

// +build fuchsia
// +build cgo

package mxc

// #cgo fuchsia LDFLAGS: -lfdio
// #include <zircon/types.h>
// #include <zircon/syscalls.h>
// #include <stdlib.h>
// #include <lib/fdio/util.h>
import "C"
import (
	"errors"
	"syscall/zx"
	"syscall/zx/fdio"
	"syscall/zx/fidl"
	"syscall/zx/io"
)

func transferFDIOFromCFD(fd int) (fdio.FDIO, error) {
	handlesC := make([]C.zx_handle_t, fdio.MaxUnderlyingHandles)
	typesC := make([]C.uint32_t, fdio.MaxUnderlyingHandles)
	status := C.fdio_transfer_fd(C.int(fd), 0, (*C.zx_handle_t)(&handlesC[0]), (*C.uint32_t)(&typesC[0]))
	if status < 0 {
		return nil, zx.Error{Status: zx.Status(status), Text: "mxc"}
	} else if status == 0 || fdio.MaxUnderlyingHandles < status {
		return nil, errors.New("Invalid handle from fdio_transfer_fd")
	}
	handles := make([]zx.Handle, int(status))
	for i := 0; i < int(status); i++ {
		handles[i] = zx.Handle(handlesC[i])
	}
	switch zx.HandleInfo(typesC[0]).Type() {
	case fdio.HandleTypeRemote:
		obj := (*io.ObjectInterface)(&fidl.Proxy{Channel: zx.Channel(handles[0])})
		if len(handles) > 1 {
			for _, h := range handles[1:] {
				h.Close()
			}
		}
		return &fdio.File{Node: fdio.Node{Object: fdio.Object{obj}}}, nil
	case fdio.HandleTypePipe:
		if len(handles) > 1 {
			for _, h := range handles[1:] {
				h.Close()
			}
		}
		return fdio.NewPipe(zx.Socket(handles[0])), nil
	default:
		for _, h := range handles {
			h.Close()
		}
		return nil, errors.New("Unexpected C handle type")
	}
}