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-rw-r--r--pkg/sentry/fsimpl/devpts/master.go226
1 files changed, 226 insertions, 0 deletions
diff --git a/pkg/sentry/fsimpl/devpts/master.go b/pkg/sentry/fsimpl/devpts/master.go
new file mode 100644
index 000000000..04a292927
--- /dev/null
+++ b/pkg/sentry/fsimpl/devpts/master.go
@@ -0,0 +1,226 @@
+// Copyright 2020 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 devpts
+
+import (
+ "gvisor.dev/gvisor/pkg/abi/linux"
+ "gvisor.dev/gvisor/pkg/context"
+ "gvisor.dev/gvisor/pkg/sentry/arch"
+ "gvisor.dev/gvisor/pkg/sentry/fsimpl/kernfs"
+ "gvisor.dev/gvisor/pkg/sentry/kernel/auth"
+ "gvisor.dev/gvisor/pkg/sentry/unimpl"
+ "gvisor.dev/gvisor/pkg/sentry/vfs"
+ "gvisor.dev/gvisor/pkg/syserror"
+ "gvisor.dev/gvisor/pkg/usermem"
+ "gvisor.dev/gvisor/pkg/waiter"
+)
+
+// LINT.IfChange
+
+// masterInode is the inode for the master end of the Terminal.
+type masterInode struct {
+ kernfs.InodeAttrs
+ kernfs.InodeNoopRefCount
+ kernfs.InodeNotDirectory
+ kernfs.InodeNotSymlink
+
+ // Keep a reference to this inode's dentry.
+ dentry kernfs.Dentry
+
+ // root is the devpts root inode.
+ root *rootInode
+}
+
+var _ kernfs.Inode = (*masterInode)(nil)
+
+// Open implements kernfs.Inode.Open.
+func (mi *masterInode) Open(ctx context.Context, rp *vfs.ResolvingPath, vfsd *vfs.Dentry, opts vfs.OpenOptions) (*vfs.FileDescription, error) {
+ t, err := mi.root.allocateTerminal(rp.Credentials())
+ if err != nil {
+ return nil, err
+ }
+
+ mi.IncRef()
+ fd := &masterFileDescription{
+ inode: mi,
+ t: t,
+ }
+ if err := fd.vfsfd.Init(fd, opts.Flags, rp.Mount(), vfsd, &vfs.FileDescriptionOptions{}); err != nil {
+ mi.DecRef()
+ return nil, err
+ }
+ return &fd.vfsfd, nil
+}
+
+// Stat implements kernfs.Inode.Stat.
+func (mi *masterInode) Stat(vfsfs *vfs.Filesystem, opts vfs.StatOptions) (linux.Statx, error) {
+ statx, err := mi.InodeAttrs.Stat(vfsfs, opts)
+ if err != nil {
+ return linux.Statx{}, err
+ }
+ statx.Blksize = 1024
+ statx.RdevMajor = linux.TTYAUX_MAJOR
+ statx.RdevMinor = linux.PTMX_MINOR
+ return statx, nil
+}
+
+// SetStat implements kernfs.Inode.SetStat
+func (mi *masterInode) SetStat(ctx context.Context, vfsfs *vfs.Filesystem, creds *auth.Credentials, opts vfs.SetStatOptions) error {
+ if opts.Stat.Mask&linux.STATX_SIZE != 0 {
+ return syserror.EINVAL
+ }
+ return mi.InodeAttrs.SetStat(ctx, vfsfs, creds, opts)
+}
+
+type masterFileDescription struct {
+ vfsfd vfs.FileDescription
+ vfs.FileDescriptionDefaultImpl
+
+ inode *masterInode
+ t *Terminal
+}
+
+var _ vfs.FileDescriptionImpl = (*masterFileDescription)(nil)
+
+// Release implements vfs.FileDescriptionImpl.Release.
+func (mfd *masterFileDescription) Release() {
+ mfd.inode.root.masterClose(mfd.t)
+ mfd.inode.DecRef()
+}
+
+// EventRegister implements waiter.Waitable.EventRegister.
+func (mfd *masterFileDescription) EventRegister(e *waiter.Entry, mask waiter.EventMask) {
+ mfd.t.ld.masterWaiter.EventRegister(e, mask)
+}
+
+// EventUnregister implements waiter.Waitable.EventUnregister.
+func (mfd *masterFileDescription) EventUnregister(e *waiter.Entry) {
+ mfd.t.ld.masterWaiter.EventUnregister(e)
+}
+
+// Readiness implements waiter.Waitable.Readiness.
+func (mfd *masterFileDescription) Readiness(mask waiter.EventMask) waiter.EventMask {
+ return mfd.t.ld.masterReadiness()
+}
+
+// Read implements vfs.FileDescriptionImpl.Read.
+func (mfd *masterFileDescription) Read(ctx context.Context, dst usermem.IOSequence, _ vfs.ReadOptions) (int64, error) {
+ return mfd.t.ld.outputQueueRead(ctx, dst)
+}
+
+// Write implements vfs.FileDescriptionImpl.Write.
+func (mfd *masterFileDescription) Write(ctx context.Context, src usermem.IOSequence, _ vfs.WriteOptions) (int64, error) {
+ return mfd.t.ld.inputQueueWrite(ctx, src)
+}
+
+// Ioctl implements vfs.FileDescriptionImpl.Ioctl.
+func (mfd *masterFileDescription) Ioctl(ctx context.Context, io usermem.IO, args arch.SyscallArguments) (uintptr, error) {
+ switch cmd := args[1].Uint(); cmd {
+ case linux.FIONREAD: // linux.FIONREAD == linux.TIOCINQ
+ // Get the number of bytes in the output queue read buffer.
+ return 0, mfd.t.ld.outputQueueReadSize(ctx, io, args)
+ case linux.TCGETS:
+ // N.B. TCGETS on the master actually returns the configuration
+ // of the slave end.
+ return mfd.t.ld.getTermios(ctx, io, args)
+ case linux.TCSETS:
+ // N.B. TCSETS on the master actually affects the configuration
+ // of the slave end.
+ return mfd.t.ld.setTermios(ctx, io, args)
+ case linux.TCSETSW:
+ // TODO(b/29356795): This should drain the output queue first.
+ return mfd.t.ld.setTermios(ctx, io, args)
+ case linux.TIOCGPTN:
+ _, err := usermem.CopyObjectOut(ctx, io, args[2].Pointer(), uint32(mfd.t.n), usermem.IOOpts{
+ AddressSpaceActive: true,
+ })
+ return 0, err
+ case linux.TIOCSPTLCK:
+ // TODO(b/29356795): Implement pty locking. For now just pretend we do.
+ return 0, nil
+ case linux.TIOCGWINSZ:
+ return 0, mfd.t.ld.windowSize(ctx, io, args)
+ case linux.TIOCSWINSZ:
+ return 0, mfd.t.ld.setWindowSize(ctx, io, args)
+ case linux.TIOCSCTTY:
+ // Make the given terminal the controlling terminal of the
+ // calling process.
+ return 0, mfd.t.setControllingTTY(ctx, io, args, true /* isMaster */)
+ case linux.TIOCNOTTY:
+ // Release this process's controlling terminal.
+ return 0, mfd.t.releaseControllingTTY(ctx, io, args, true /* isMaster */)
+ case linux.TIOCGPGRP:
+ // Get the foreground process group.
+ return mfd.t.foregroundProcessGroup(ctx, io, args, true /* isMaster */)
+ case linux.TIOCSPGRP:
+ // Set the foreground process group.
+ return mfd.t.setForegroundProcessGroup(ctx, io, args, true /* isMaster */)
+ default:
+ maybeEmitUnimplementedEvent(ctx, cmd)
+ return 0, syserror.ENOTTY
+ }
+}
+
+// SetStat implements vfs.FileDescriptionImpl.SetStat.
+func (mfd *masterFileDescription) SetStat(ctx context.Context, opts vfs.SetStatOptions) error {
+ creds := auth.CredentialsFromContext(ctx)
+ fs := mfd.vfsfd.VirtualDentry().Mount().Filesystem()
+ return mfd.inode.SetStat(ctx, fs, creds, opts)
+}
+
+// Stat implements vfs.FileDescriptionImpl.Stat.
+func (mfd *masterFileDescription) Stat(ctx context.Context, opts vfs.StatOptions) (linux.Statx, error) {
+ fs := mfd.vfsfd.VirtualDentry().Mount().Filesystem()
+ return mfd.inode.Stat(fs, opts)
+}
+
+// maybeEmitUnimplementedEvent emits unimplemented event if cmd is valid.
+func maybeEmitUnimplementedEvent(ctx context.Context, cmd uint32) {
+ switch cmd {
+ case linux.TCGETS,
+ linux.TCSETS,
+ linux.TCSETSW,
+ linux.TCSETSF,
+ linux.TIOCGWINSZ,
+ linux.TIOCSWINSZ,
+ linux.TIOCSETD,
+ linux.TIOCSBRK,
+ linux.TIOCCBRK,
+ linux.TCSBRK,
+ linux.TCSBRKP,
+ linux.TIOCSTI,
+ linux.TIOCCONS,
+ linux.FIONBIO,
+ linux.TIOCEXCL,
+ linux.TIOCNXCL,
+ linux.TIOCGEXCL,
+ linux.TIOCGSID,
+ linux.TIOCGETD,
+ linux.TIOCVHANGUP,
+ linux.TIOCGDEV,
+ linux.TIOCMGET,
+ linux.TIOCMSET,
+ linux.TIOCMBIC,
+ linux.TIOCMBIS,
+ linux.TIOCGICOUNT,
+ linux.TCFLSH,
+ linux.TIOCSSERIAL,
+ linux.TIOCGPTPEER:
+
+ unimpl.EmitUnimplementedEvent(ctx)
+ }
+}
+
+// LINT.ThenChange(../../fs/tty/master.go)