1// Copyright 2018 The Prometheus Authors
2// Licensed under the Apache License, Version 2.0 (the "License");
3// you may not use this file except in compliance with the License.
4// You may obtain a copy of the License at
5//
6// http://www.apache.org/licenses/LICENSE-2.0
7//
8// Unless required by applicable law or agreed to in writing, software
9// distributed under the License is distributed on an "AS IS" BASIS,
10// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
11// See the License for the specific language governing permissions and
12// limitations under the License.
13
14package procfs
15
16import (
17	"fmt"
18	"os"
19	"strconv"
20	"strings"
21)
22
23// Namespace represents a single namespace of a process.
24type Namespace struct {
25	Type  string // Namespace type.
26	Inode uint32 // Inode number of the namespace. If two processes are in the same namespace their inodes will match.
27}
28
29// Namespaces contains all of the namespaces that the process is contained in.
30type Namespaces map[string]Namespace
31
32// Namespaces reads from /proc/<pid>/ns/* to get the namespaces of which the
33// process is a member.
34func (p Proc) Namespaces() (Namespaces, error) {
35	d, err := os.Open(p.path("ns"))
36	if err != nil {
37		return nil, err
38	}
39	defer d.Close()
40
41	names, err := d.Readdirnames(-1)
42	if err != nil {
43		return nil, fmt.Errorf("failed to read contents of ns dir: %w", err)
44	}
45
46	ns := make(Namespaces, len(names))
47	for _, name := range names {
48		target, err := os.Readlink(p.path("ns", name))
49		if err != nil {
50			return nil, err
51		}
52
53		fields := strings.SplitN(target, ":", 2)
54		if len(fields) != 2 {
55			return nil, fmt.Errorf("failed to parse namespace type and inode from %q", target)
56		}
57
58		typ := fields[0]
59		inode, err := strconv.ParseUint(strings.Trim(fields[1], "[]"), 10, 32)
60		if err != nil {
61			return nil, fmt.Errorf("failed to parse inode from %q: %w", fields[1], err)
62		}
63
64		ns[name] = Namespace{typ, uint32(inode)}
65	}
66
67	return ns, nil
68}
69