mirror of
https://github.com/octoleo/restic.git
synced 2024-11-29 16:23:59 +00:00
05958caf6e
This is a follow-up on fb9729fdb9, which
runs the `ssh` in its own process group and selects that process group
as the foreground group. After the sftp connection is established,
restic switches back to the previous foreground process group.
This allows `ssh` to prompt for the password, but it won't receive
the interrupt signal (SIGINT, ^C) later on, because it is not in the
foreground process group any more, allowing a clean tear down.
74 lines
1.5 KiB
Go
74 lines
1.5 KiB
Go
// +build !windows
|
|
|
|
package sftp
|
|
|
|
import (
|
|
"os"
|
|
"os/exec"
|
|
"os/signal"
|
|
"syscall"
|
|
"unsafe"
|
|
|
|
"github.com/restic/restic/internal/errors"
|
|
)
|
|
|
|
func tcsetpgrp(fd int, pid int) error {
|
|
_, _, errno := syscall.RawSyscall(syscall.SYS_IOCTL, uintptr(fd),
|
|
uintptr(syscall.TIOCSPGRP), uintptr(unsafe.Pointer(&pid)))
|
|
if errno == 0 {
|
|
return nil
|
|
}
|
|
|
|
return errno
|
|
}
|
|
|
|
// startForeground runs cmd in the foreground, by temporarily switching to the
|
|
// new process group created for cmd. The returned function `bg` switches back
|
|
// to the previous process group.
|
|
func startForeground(cmd *exec.Cmd) (bg func() error, err error) {
|
|
// open the TTY, we need the file descriptor
|
|
tty, err := os.OpenFile("/dev/tty", os.O_RDWR, 0)
|
|
if err != nil {
|
|
return nil, errors.Wrap(err, "open TTY")
|
|
}
|
|
|
|
signal.Ignore(syscall.SIGTTIN)
|
|
signal.Ignore(syscall.SIGTTOU)
|
|
|
|
// run the command in its own process group
|
|
cmd.SysProcAttr = &syscall.SysProcAttr{
|
|
Setpgid: true,
|
|
}
|
|
|
|
// start the process
|
|
err = cmd.Start()
|
|
if err != nil {
|
|
_ = tty.Close()
|
|
return nil, errors.Wrap(err, "cmd.Start")
|
|
}
|
|
|
|
// move the command's process group into the foreground
|
|
prev := syscall.Getpgrp()
|
|
err = tcsetpgrp(int(tty.Fd()), cmd.Process.Pid)
|
|
if err != nil {
|
|
_ = tty.Close()
|
|
return nil, err
|
|
}
|
|
|
|
bg = func() error {
|
|
signal.Reset(syscall.SIGTTIN)
|
|
signal.Reset(syscall.SIGTTOU)
|
|
|
|
// reset the foreground process group
|
|
err = tcsetpgrp(int(tty.Fd()), prev)
|
|
if err != nil {
|
|
_ = tty.Close()
|
|
return err
|
|
}
|
|
|
|
return tty.Close()
|
|
}
|
|
|
|
return bg, nil
|
|
}
|