76c62f2722
Given that we're only interested in detecting if userns is enabled, and no further details about the mapping, we can revert this function to go back to its original implementation in github.com/lxc/lxd/shared/util.go Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
54 lines
1.3 KiB
Go
54 lines
1.3 KiB
Go
/*
|
|
Copyright The containerd Authors.
|
|
|
|
Licensed under the Apache License, Version 2.0 (the "License");
|
|
you may not use this file except in compliance with the License.
|
|
You may obtain a copy of the License at
|
|
|
|
http://www.apache.org/licenses/LICENSE-2.0
|
|
|
|
Unless required by applicable law or agreed to in writing, software
|
|
distributed under the License is distributed on an "AS IS" BASIS,
|
|
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
See the License for the specific language governing permissions and
|
|
limitations under the License.
|
|
*/
|
|
|
|
package sys
|
|
|
|
import (
|
|
"bufio"
|
|
"fmt"
|
|
"os"
|
|
)
|
|
|
|
// RunningInUserNS detects whether we are currently running in a user namespace.
|
|
// Originally 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
|
|
}
|