go
/
gvisor
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

Always set SysProcAttr.Ctty to an FD in the child's FD table. 

Go was going to change the behavior of SysProcAttr.Ctty such that it must be an
FD in the *parent* FD table:
https://go-review.googlesource.com/c/go/+/178919/

However, after some debate, it was decided that this change was too
backwards-incompatible, and so it was reverted.
https://github.com/golang/go/issues/29458

The behavior going forward is unchanged: the Ctty FD must be an FD in the
*child* FD table.

PiperOrigin-RevId: 255228476
This commit is contained in:
Nicolas Lacasse 2019-06-26 11:26:18 -07:00 committed by gVisor bot
parent e98ce4a2c6
commit 67e2f227aa
5 changed files with 9 additions and 70 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

16
runsc/cmd/exec.go
View File

@ -235,18 +235,12 @@ func (ex *Exec) execChildAndWait(waitStatus *syscall.WaitStatus) subcommands.Exi
cmd.SysProcAttr = &syscall.SysProcAttr{
Setsid: true,
Setctty: true,
Ctty: int(tty.Fd()),
// The Ctty FD must be the FD in the child process's FD
// table. Since we set cmd.Stdin/Stdout/Stderr to the
// tty FD, we can use any of 0, 1, or 2 here.
// See https://github.com/golang/go/issues/29458.
Ctty: 0,
}
// TODO(b/133868570): Delete this check once Go 1.12 is no
// longer supported.
if console.CttyFdIsPostShuffle {
// In go1.12 and before, the Ctty FD must be the FD in
// the child process's FD table. Since we set
// cmd.Stdin/Stdout/Stderr to the tty FD, we can use
// any of 0, 1, or 2 here.
cmd.SysProcAttr.Ctty = 0
}
}
if err := cmd.Start(); err != nil {

2
runsc/console/BUILD
View File

@ -6,8 +6,6 @@ go_library(
name = "console",
srcs = [
"console.go",
"ctty_1_12.go",
"ctty_1_13.go",
],
importpath = "gvisor.dev/gvisor/runsc/console",
visibility = [

24
runsc/console/ctty_1_12.go
View File

@ -1,24 +0,0 @@
// Copyright 2019 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.
// +build go1.12
// +build !go1.13
// TODO(b/133868570): Delete once Go 1.12 is no longer supported.
package console
// CttyFdIsPostShuffle indicates that in go1.12 and earlier, the
// SysProcAttr.Ctty FD is determined "pre-shuffle" (not "post-shuffle").
var CttyFdIsPostShuffle = false

24
runsc/console/ctty_1_13.go
View File

@ -1,24 +0,0 @@
// Copyright 2019 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.
// +build go1.13
// +build !go1.14
// TODO(b/133868570): Delete once Go 1.12 is no longer supported.
package console
// CttyFdIsPostShuffle indicates that in go1.13 and later, the SysProcAttr.Ctty
// FD is determined "post-shuffle".
var CttyFdIsPostShuffle = true

13
runsc/sandbox/sandbox.go
View File

@ -438,15 +438,10 @@ func (s *Sandbox) createSandboxProcess(conf *boot.Config, args *Args, startSyncF
// Set the TTY as a controlling TTY on the sandbox process.
cmd.SysProcAttr.Setctty = true
cmd.SysProcAttr.Ctty = int(tty.Fd())
// TODO(b/133868570): Delete this check once Go 1.12 is no
// longer supported.
if console.CttyFdIsPostShuffle {
// In go1.12 and before, the Ctty FD must be the FD in
// the child process's FD table, which will be "nextFD"
// in this case.
cmd.SysProcAttr.Ctty = nextFD
}
// The Ctty FD must be the FD in the child process's FD table,
// which will be nextFD in this case.
// See https://github.com/golang/go/issues/29458.
cmd.SysProcAttr.Ctty = nextFD
// Pass the tty as all stdio fds to sandbox.
for i := 0; i < 3; i++ {