1 files changed, 89 insertions, 0 deletions
diff --git a/runsc/boot/fds.go b/runsc/boot/fds.go
new file mode 100644
index 000000000..4e428b49c
--- /dev/null
+++ b/runsc/boot/fds.go
@@ -0,0 +1,89 @@
+// Copyright 2018 The gVisor Authors.
+//
+// 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"
+
+	"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.
+// Upon success, createFDMap dups then closes stdioFDs.
+func createFDMap(ctx context.Context, k *kernel.Kernel, l *limits.LimitSet, console bool, stdioFDs []int) (*kernel.FDMap, error) {
+	if len(stdioFDs) != 3 {
+		return nil, fmt.Errorf("stdioFDs should contain exactly 3 FDs (stdin, stdout, and stderr), but %d FDs received", len(stdioFDs))
+	}
+
+	fdm := k.NewFDMap()
+	defer fdm.DecRef()
+	mounter := fs.FileOwnerFromContext(ctx)
+
+	// Maps sandbox FD to host FD.
+	fdMap := map[int]int{
+		0: stdioFDs[0],
+		1: stdioFDs[1],
+		2: stdioFDs[2],
+	}
+
+	var ttyFile *fs.File
+	for appFD, hostFD := range fdMap {
+		var appFile *fs.File
+
+		if console && appFD < 3 {
+			// Import the file as a host TTY file.
+			if ttyFile == nil {
+				var err error
+				appFile, err = host.ImportFile(ctx, hostFD, mounter, true /* isTTY */)
+				if err != nil {
+					return nil, err
+				}
+				defer appFile.DecRef()
+
+				// Remember this in the TTY file, as we will
+				// use it for the other stdio FDs.
+				ttyFile = appFile
+			} else {
+				// Re-use the existing TTY file, as all three
+				// stdio FDs must point to the same fs.File in
+				// order to share TTY state, specifically the
+				// foreground process group id.
+				appFile = ttyFile
+			}
+		} else {
+			// Import the file as a regular host file.
+			var err error
+			appFile, err = host.ImportFile(ctx, hostFD, mounter, false /* isTTY */)
+			if err != nil {
+				return nil, err
+			}
+			defer appFile.DecRef()
+		}
+
+		// Add the file to the FD map.
+		if err := fdm.NewFDAt(kdefs.FD(appFD), appFile, kernel.FDFlags{}, l); err != nil {
+			return nil, err
+		}
+	}
+
+	fdm.IncRef()
+	return fdm, nil
+}