Check in gVisor.

PiperOrigin-RevId: 194583126
Change-Id: Ica1d8821a90f74e7e745962d71801c598c652463

1 files changed, 143 insertions, 0 deletions

diff --git a/pkg/sentry/fs/tty/inode.go b/pkg/sentry/fs/tty/inode.go
new file mode 100644
index 000000000..04b9a7727
--- /dev/null
+++ b/pkg/sentry/fs/tty/inode.go
@@ -0,0 +1,143 @@
+// 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 tty
+
+import (
+	"sync"
+
+	"gvisor.googlesource.com/gvisor/pkg/abi/linux"
+	"gvisor.googlesource.com/gvisor/pkg/sentry/context"
+	"gvisor.googlesource.com/gvisor/pkg/sentry/fs"
+	"gvisor.googlesource.com/gvisor/pkg/sentry/fs/fsutil"
+	ktime "gvisor.googlesource.com/gvisor/pkg/sentry/kernel/time"
+	"gvisor.googlesource.com/gvisor/pkg/syserror"
+)
+
+// inodeOperations are the base fs.InodeOperations for master and slave Inodes.
+//
+// inodeOperations does not implement:
+//
+// * fs.InodeOperations.Release
+// * fs.InodeOperations.GetFile
+type inodeOperations struct {
+	fsutil.DeprecatedFileOperations  `state:"nosave"`
+	fsutil.InodeNoExtendedAttributes `state:"nosave"`
+	fsutil.InodeNotDirectory         `state:"nosave"`
+	fsutil.InodeNotRenameable        `state:"nosave"`
+	fsutil.InodeNotSocket            `state:"nosave"`
+	fsutil.InodeNotSymlink           `state:"nosave"`
+	fsutil.NoMappable                `state:"nosave"`
+	fsutil.NoopWriteOut              `state:"nosave"`
+
+	// mu protects the fields below.
+	mu sync.Mutex `state:"nosave"`
+
+	// uattr is the inode's UnstableAttr.
+	uattr fs.UnstableAttr
+}
+
+// UnstableAttr implements fs.InodeOperations.UnstableAttr.
+func (i *inodeOperations) UnstableAttr(ctx context.Context, inode *fs.Inode) (fs.UnstableAttr, error) {
+	i.mu.Lock()
+	defer i.mu.Unlock()
+	return i.uattr, nil
+}
+
+// Check implements fs.InodeOperations.Check.
+func (i *inodeOperations) Check(ctx context.Context, inode *fs.Inode, p fs.PermMask) bool {
+	return fs.ContextCanAccessFile(ctx, inode, p)
+}
+
+// SetPermissions implements fs.InodeOperations.SetPermissions
+func (i *inodeOperations) SetPermissions(ctx context.Context, inode *fs.Inode, p fs.FilePermissions) bool {
+	i.mu.Lock()
+	defer i.mu.Unlock()
+	i.uattr.Perms = p
+	i.uattr.StatusChangeTime = ktime.NowFromContext(ctx)
+	return true
+}
+
+// SetOwner implements fs.InodeOperations.SetOwner.
+func (i *inodeOperations) SetOwner(ctx context.Context, inode *fs.Inode, owner fs.FileOwner) error {
+	i.mu.Lock()
+	defer i.mu.Unlock()
+	if owner.UID.Ok() {
+		i.uattr.Owner.UID = owner.UID
+	}
+	if owner.GID.Ok() {
+		i.uattr.Owner.GID = owner.GID
+	}
+	return nil
+}
+
+// SetTimestamps implements fs.InodeOperations.SetTimestamps.
+func (i *inodeOperations) SetTimestamps(ctx context.Context, inode *fs.Inode, ts fs.TimeSpec) error {
+	if ts.ATimeOmit && ts.MTimeOmit {
+		return nil
+	}
+
+	i.mu.Lock()
+	defer i.mu.Unlock()
+
+	now := ktime.NowFromContext(ctx)
+	if !ts.ATimeOmit {
+		if ts.ATime.IsZero() {
+			i.uattr.AccessTime = now
+		} else {
+			i.uattr.AccessTime = ts.ATime
+		}
+	}
+	if !ts.MTimeOmit {
+		if ts.MTime.IsZero() {
+			i.uattr.ModificationTime = now
+		} else {
+			i.uattr.ModificationTime = ts.MTime
+		}
+	}
+	i.uattr.StatusChangeTime = now
+	return nil
+}
+
+// Truncate implements fs.InodeOperations.Truncate.
+func (i *inodeOperations) Truncate(ctx context.Context, inode *fs.Inode, size int64) error {
+	return syserror.EINVAL
+}
+
+// AddLink implements fs.InodeOperations.AddLink.
+func (i *inodeOperations) AddLink() {
+}
+
+// DropLink implements fs.InodeOperations.DropLink.
+func (i *inodeOperations) DropLink() {
+}
+
+// NotifyStatusChange implements fs.InodeOperations.NotifyStatusChange.
+func (i *inodeOperations) NotifyStatusChange(ctx context.Context) {
+	i.mu.Lock()
+	defer i.mu.Unlock()
+	i.uattr.StatusChangeTime = ktime.NowFromContext(ctx)
+}
+
+// IsVirtual implements fs.InodeOperations.IsVirtual.
+func (i *inodeOperations) IsVirtual() bool {
+	return true
+}
+
+// StatFS implements fs.InodeOperations.StatFS.
+func (i *inodeOperations) StatFS(ctx context.Context) (fs.Info, error) {
+	return fs.Info{
+		Type: linux.DEVPTS_SUPER_MAGIC,
+	}, nil
+}