johnsonjh/gfpsgo

// Copyright 2021 Jeffrey H. Johnson <trnsz@pobox.com>
// Copyright 2018 psgo 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 proc

import (
    "fmt"
    "io/ioutil"
    "os"
    "strings"
)

// ParseAttrCurrent returns the contents of /proc/$pid/attr/current of "?" if
// labeling is not supported on the host.
func ParseAttrCurrent(pid string) (string, error) {
    data, err := ioutil.ReadFile(fmt.Sprintf("/proc/%s/attr/current", pid))
    if err != nil {
        _, err = os.Stat(fmt.Sprintf("/proc/%s", pid))
        if os.IsNotExist(err) {
            // PID doesn't exist
            return "", err
        }
        // PID exists but labeling seems to be unsupported
        return "?", nil
    }
    return strings.Trim(string(data), "\n"), nil
}