Revert "Merge pull request 101888 from kolyshkin/update-runc-rc94"

This reverts commit b1b06fe0a4, reversing
changes made to 382a33986b.

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

@@ -3,9 +3,12 @@
 package system
 
 import (
+	"os"
 	"os/exec"
+	"sync"
 	"unsafe"
 
+	"github.com/opencontainers/runc/libcontainer/user"
 	"golang.org/x/sys/unix"
 )
 
@@ -84,6 +87,52 @@ func Setctty() error {
 	return nil
 }
 
+var (
+	inUserNS bool
+	nsOnce   sync.Once
+)
+
+// RunningInUserNS detects whether we are currently running in a user namespace.
+// Originally copied from github.com/lxc/lxd/shared/util.go
+func RunningInUserNS() bool {
+	nsOnce.Do(func() {
+		uidmap, err := user.CurrentProcessUIDMap()
+		if err != nil {
+			// This kernel-provided file only exists if user namespaces are supported
+			return
+		}
+		inUserNS = UIDMapInUserNS(uidmap)
+	})
+	return inUserNS
+}
+
+func UIDMapInUserNS(uidmap []user.IDMap) bool {
+	/*
+	 * We assume we are in the initial user namespace if we have a full
+	 * range - 4294967295 uids starting at uid 0.
+	 */
+	if len(uidmap) == 1 && uidmap[0].ID == 0 && uidmap[0].ParentID == 0 && uidmap[0].Count == 4294967295 {
+		return false
+	}
+	return true
+}
+
+// GetParentNSeuid returns the euid within the parent user namespace
+func GetParentNSeuid() int64 {
+	euid := int64(os.Geteuid())
+	uidmap, err := user.CurrentProcessUIDMap()
+	if err != nil {
+		// This kernel-provided file only exists if user namespaces are supported
+		return euid
+	}
+	for _, um := range uidmap {
+		if um.ID <= euid && euid <= um.ID+um.Count-1 {
+			return um.ParentID + euid - um.ID
+		}
+	}
+	return euid
+}
+
 // 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)

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

@@ -0,0 +1,27 @@
+// +build !linux
+
+package system
+
+import (
+	"os"
+
+	"github.com/opencontainers/runc/libcontainer/user"
+)
+
+// RunningInUserNS is a stub for non-Linux systems
+// Always returns false
+func RunningInUserNS() bool {
+	return false
+}
+
+// UIDMapInUserNS is a stub for non-Linux systems
+// Always returns false
+func UIDMapInUserNS(uidmap []user.IDMap) bool {
+	return false
+}
+
+// GetParentNSeuid returns the euid within the parent user namespace
+// Always returns os.Geteuid on non-linux
+func GetParentNSeuid() int {
+	return os.Geteuid()
+}

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

@@ -1,5 +0,0 @@
-package system
-
-import "github.com/opencontainers/runc/libcontainer/userns"
-
-var RunningInUserNS = userns.RunningInUserNS