forked from opencontainers/umoci
/
util.go
54 lines (48 loc) · 1.52 KB
/
util.go
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/*
* lxd: daemon based on liblxd with a REST API
* Copyright (C) 2015-2017 LXD 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.
*/
// This code was copied from https://github.com/lxc/lxd, which is available
// under the the Apache 2.0 license (as noted above). The version of this code
// comes from the tag lxd-2.21 at /shared/util.go.
package shared
import (
"bufio"
"fmt"
"os"
)
// RunningInUserNS returns whether the current process is (likely) inside a
// user namespace. This has a possible false-negative (where it will return
// false while inside a user namespace if it was intentionally configured to be
// confusing to programs like this).
func RunningInUserNS() bool {
file, err := os.Open("/proc/self/uid_map")
if err != nil {
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)
if a == 0 && b == 0 && c == 4294967295 {
return false
}
return true
}