Check in gVisor.

PiperOrigin-RevId: 194583126
Change-Id: Ica1d8821a90f74e7e745962d71801c598c652463

1 files changed, 61 insertions, 0 deletions

diff --git a/runsc/boot/fds.go b/runsc/boot/fds.go
new file mode 100644
index 000000000..0449e243d
--- /dev/null
+++ b/runsc/boot/fds.go
@@ -0,0 +1,61 @@
+// 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
+}