Files
runc/libcontainer/system/linux.go
Kir Kolyshkin 794cd66df8 libct/system: Exec: wrap the error
If the container binary to be run is removed in between runc create
and runc start, the latter spits the following error:

> can't exec user process: no such file or directory

This is a bit confusing since we don't see what file is missing.

Wrap the unix.Exec error into os.PathError, like in many other cases,
to provide some context. Remove the error wrapping from
(*linuxStandardInit).Init as it is now redundant.

With this patch, the error is now:

> exec /bin/false: no such file or directory

Reported-by: Daniel J Walsh <dwalsh@redhat.com>
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
2021-10-07 11:09:08 -07:00

113 lines
2.2 KiB
Go

//go:build linux
// +build linux
package system
import (
"os"
"os/exec"
"unsafe"
"golang.org/x/sys/unix"
)
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 Exec(name, args, env)
}
func Exec(cmd string, args []string, env []string) error {
for {
err := unix.Exec(cmd, args, env)
if err != unix.EINTR { //nolint:errorlint // unix errors are bare
return &os.PathError{Op: "exec", Path: cmd, Err: err}
}
}
}
func Prlimit(pid, resource int, limit unix.Rlimit) error {
_, _, err := unix.RawSyscall6(unix.SYS_PRLIMIT64, uintptr(pid), uintptr(resource), uintptr(unsafe.Pointer(&limit)), uintptr(unsafe.Pointer(&limit)), 0, 0)
if err != 0 {
return err
}
return nil
}
func SetParentDeathSignal(sig uintptr) error {
if err := unix.Prctl(unix.PR_SET_PDEATHSIG, sig, 0, 0, 0); err != nil {
return err
}
return nil
}
func GetParentDeathSignal() (ParentDeathSignal, error) {
var sig int
if err := unix.Prctl(unix.PR_GET_PDEATHSIG, uintptr(unsafe.Pointer(&sig)), 0, 0, 0); err != nil {
return -1, err
}
return ParentDeathSignal(sig), nil
}
func SetKeepCaps() error {
if err := unix.Prctl(unix.PR_SET_KEEPCAPS, 1, 0, 0, 0); err != nil {
return err
}
return nil
}
func ClearKeepCaps() error {
if err := unix.Prctl(unix.PR_SET_KEEPCAPS, 0, 0, 0, 0); err != nil {
return err
}
return nil
}
func Setctty() error {
if err := unix.IoctlSetInt(0, unix.TIOCSCTTY, 0); err != nil {
return err
}
return nil
}
// SetSubreaper sets the value i as the subreaper setting for the calling process
func SetSubreaper(i int) error {
return unix.Prctl(unix.PR_SET_CHILD_SUBREAPER, uintptr(i), 0, 0, 0)
}
// GetSubreaper returns the subreaper setting for the calling process
func GetSubreaper() (int, error) {
var i uintptr
if err := unix.Prctl(unix.PR_GET_CHILD_SUBREAPER, uintptr(unsafe.Pointer(&i)), 0, 0, 0); err != nil {
return -1, err
}
return int(i), nil
}