containerd/vendor/github.com/opencontainers/runc/libcontainer/system/linux.go
Michael Crosby 2386062ce1 Update runc to e775f0fba3ea329b8b766451c892c41a3d4
This resolves logrus issues with containerd not being in sync with the
version runc is using.

This also updates the OCI runtime spec to v1.0.0

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
2017-07-31 14:33:49 -04:00

137 lines
3.2 KiB
Go

// +build linux
package system
import (
"bufio"
"fmt"
"os"
"os/exec"
"syscall" // only for exec
"unsafe"
"golang.org/x/sys/unix"
)
// If arg2 is nonzero, set the "child subreaper" attribute of the
// calling process; if arg2 is zero, unset the attribute. When a
// process is marked as a child subreaper, all of the children
// that it creates, and their descendants, will be marked as
// having a subreaper. In effect, a subreaper fulfills the role
// of init(1) for its descendant processes. Upon termination of
// a process that is orphaned (i.e., its immediate parent has
// already terminated) and marked as having a subreaper, the
// nearest still living ancestor subreaper will receive a SIGCHLD
// signal and be able to wait(2) on the process to discover its
// termination status.
const PR_SET_CHILD_SUBREAPER = 36
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 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
}
// RunningInUserNS detects whether we are currently running in a user namespace.
// Copied from github.com/lxc/lxd/shared/util.go
func RunningInUserNS() bool {
file, err := os.Open("/proc/self/uid_map")
if err != nil {
// This kernel-provided file only exists if user namespaces are supported
return false
}
defer file.Close()
buf := bufio.NewReader(file)
l, _, err := buf.ReadLine()
if err != nil {
return false
}
line := string(l)
var a, b, c int64
fmt.Sscanf(line, "%d %d %d", &a, &b, &c)
/*
* We assume we are in the initial user namespace if we have a full
* range - 4294967295 uids starting at uid 0.
*/
if a == 0 && b == 0 && c == 4294967295 {
return false
}
return true
}
// SetSubreaper sets the value i as the subreaper setting for the calling process
func SetSubreaper(i int) error {
return unix.Prctl(PR_SET_CHILD_SUBREAPER, uintptr(i), 0, 0, 0)
}