move dependencies to vendor

vendor/github.com/opencontainers/runc/libcontainer/system/linux.go

@@ -0,0 +1,77 @@
+// +build linux
+
+package system
+
+import (
+	"os/exec"
+	"syscall"
+	"unsafe"
+)
+
+type ParentDeathSignal int
+
+func (p ParentDeathSignal) Restore() error {
+	if p == 0 {
+		return nil
+	}
+	current, err := GetParentDeathSignal()
+	if err != nil {
+		return err
+	}
+	if p == current {
+		return nil
+	}
+	return p.Set()
+}
+
+func (p ParentDeathSignal) Set() error {
+	return SetParentDeathSignal(uintptr(p))
+}
+
+func Execv(cmd string, args []string, env []string) error {
+	name, err := exec.LookPath(cmd)
+	if err != nil {
+		return err
+	}
+
+	return syscall.Exec(name, args, env)
+}
+
+func SetParentDeathSignal(sig uintptr) error {
+	if _, _, err := syscall.RawSyscall(syscall.SYS_PRCTL, syscall.PR_SET_PDEATHSIG, sig, 0); err != 0 {
+		return err
+	}
+	return nil
+}
+
+func GetParentDeathSignal() (ParentDeathSignal, error) {
+	var sig int
+	_, _, err := syscall.RawSyscall(syscall.SYS_PRCTL, syscall.PR_GET_PDEATHSIG, uintptr(unsafe.Pointer(&sig)), 0)
+	if err != 0 {
+		return -1, err
+	}
+	return ParentDeathSignal(sig), nil
+}
+
+func SetKeepCaps() error {
+	if _, _, err := syscall.RawSyscall(syscall.SYS_PRCTL, syscall.PR_SET_KEEPCAPS, 1, 0); err != 0 {
+		return err
+	}
+
+	return nil
+}
+
+func ClearKeepCaps() error {
+	if _, _, err := syscall.RawSyscall(syscall.SYS_PRCTL, syscall.PR_SET_KEEPCAPS, 0, 0); err != 0 {
+		return err
+	}
+
+	return nil
+}
+
+func Setctty() error {
+	if _, _, err := syscall.RawSyscall(syscall.SYS_IOCTL, 0, uintptr(syscall.TIOCSCTTY), 0); err != 0 {
+		return err
+	}
+	return nil
+}