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// Copyright 2018 Google Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package boot
import (
"fmt"
"syscall"
"gvisor.googlesource.com/gvisor/pkg/sentry/context"
"gvisor.googlesource.com/gvisor/pkg/sentry/fs"
"gvisor.googlesource.com/gvisor/pkg/sentry/fs/host"
"gvisor.googlesource.com/gvisor/pkg/sentry/kernel"
"gvisor.googlesource.com/gvisor/pkg/sentry/kernel/kdefs"
"gvisor.googlesource.com/gvisor/pkg/sentry/limits"
)
// createFDMap creates an fd map that contains stdin, stdout, and stderr. If
// console is true, then ioctl calls will be passed through to the host fd.
//
// TODO: We currently arn't passing any FDs in to the sandbox, so
// there's not much else for this function to do. It will get more complicated
// when gofers enter the picture. Also the LISTEN_FDS environment variable
// allows passing arbitrary FDs to the sandbox, which we do not yet support.
func createFDMap(ctx context.Context, k *kernel.Kernel, l *limits.LimitSet, console bool) (*kernel.FDMap, error) {
fdm := k.NewFDMap()
defer fdm.DecRef()
// Maps sandbox fd to host fd.
fdMap := map[int]int{
0: syscall.Stdin,
1: syscall.Stdout,
2: syscall.Stderr,
}
mounter := fs.FileOwnerFromContext(ctx)
for sfd, hfd := range fdMap {
file, err := host.ImportFile(ctx, hfd, mounter, console /* allow ioctls */)
if err != nil {
return nil, fmt.Errorf("failed to import fd %d: %v", hfd, err)
}
defer file.DecRef()
if err := fdm.NewFDAt(kdefs.FD(sfd), file, kernel.FDFlags{}, l); err != nil {
return nil, fmt.Errorf("failed to add imported fd %d to FDMap: %v", hfd, err)
}
}
fdm.IncRef()
return fdm, nil
}
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