56 lines
1.5 KiB
Go
56 lines
1.5 KiB
Go
// +build !solaris
|
|
|
|
package main
|
|
|
|
import (
|
|
"fmt"
|
|
"os"
|
|
"syscall"
|
|
"unsafe"
|
|
)
|
|
|
|
// NewConsole returns an initialized console that can be used within a container by copying bytes
|
|
// from the master side to the slave that is attached as the tty for the container's init process.
|
|
func newConsole(uid, gid int) (*os.File, string, error) {
|
|
master, err := os.OpenFile("/dev/ptmx", syscall.O_RDWR|syscall.O_NOCTTY|syscall.O_CLOEXEC, 0)
|
|
if err != nil {
|
|
return nil, "", err
|
|
}
|
|
console, err := ptsname(master)
|
|
if err != nil {
|
|
return nil, "", err
|
|
}
|
|
if err := unlockpt(master); err != nil {
|
|
return nil, "", err
|
|
}
|
|
if err := os.Chmod(console, 0600); err != nil {
|
|
return nil, "", err
|
|
}
|
|
if err := os.Chown(console, uid, gid); err != nil {
|
|
return nil, "", err
|
|
}
|
|
return master, console, nil
|
|
}
|
|
|
|
func ioctl(fd uintptr, flag, data uintptr) error {
|
|
if _, _, err := syscall.Syscall(syscall.SYS_IOCTL, fd, flag, data); err != 0 {
|
|
return err
|
|
}
|
|
return nil
|
|
}
|
|
|
|
// unlockpt unlocks the slave pseudoterminal device corresponding to the master pseudoterminal referred to by f.
|
|
// unlockpt should be called before opening the slave side of a pty.
|
|
func unlockpt(f *os.File) error {
|
|
var u int32
|
|
return ioctl(f.Fd(), syscall.TIOCSPTLCK, uintptr(unsafe.Pointer(&u)))
|
|
}
|
|
|
|
// ptsname retrieves the name of the first available pts for the given master.
|
|
func ptsname(f *os.File) (string, error) {
|
|
var n int32
|
|
if err := ioctl(f.Fd(), syscall.TIOCGPTN, uintptr(unsafe.Pointer(&n))); err != nil {
|
|
return "", err
|
|
}
|
|
return fmt.Sprintf("/dev/pts/%d", n), nil
|
|
}
|