aboutsummaryrefslogtreecommitdiff
path: root/vendor/github.com/prometheus/procfs/proc_fdinfo.go
blob: a76ca7079194030248abdc376ac1694bc5cb26e0 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
// Copyright 2019 The Prometheus 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 procfs

import (
	"bufio"
	"bytes"
	"errors"
	"regexp"

	"github.com/prometheus/procfs/internal/util"
)

// Regexp variables
var (
	rPos          = regexp.MustCompile(`^pos:\s+(\d+)$`)
	rFlags        = regexp.MustCompile(`^flags:\s+(\d+)$`)
	rMntID        = regexp.MustCompile(`^mnt_id:\s+(\d+)$`)
	rInotify      = regexp.MustCompile(`^inotify`)
	rInotifyParts = regexp.MustCompile(`^inotify\s+wd:([0-9a-f]+)\s+ino:([0-9a-f]+)\s+sdev:([0-9a-f]+)(?:\s+mask:([0-9a-f]+))?`)
)

// ProcFDInfo contains represents file descriptor information.
type ProcFDInfo struct {
	// File descriptor
	FD string
	// File offset
	Pos string
	// File access mode and status flags
	Flags string
	// Mount point ID
	MntID string
	// List of inotify lines (structured) in the fdinfo file (kernel 3.8+ only)
	InotifyInfos []InotifyInfo
}

// FDInfo constructor. On kernels older than 3.8, InotifyInfos will always be empty.
func (p Proc) FDInfo(fd string) (*ProcFDInfo, error) {
	data, err := util.ReadFileNoStat(p.path("fdinfo", fd))
	if err != nil {
		return nil, err
	}

	var text, pos, flags, mntid string
	var inotify []InotifyInfo

	scanner := bufio.NewScanner(bytes.NewReader(data))
	for scanner.Scan() {
		text = scanner.Text()
		if rPos.MatchString(text) {
			pos = rPos.FindStringSubmatch(text)[1]
		} else if rFlags.MatchString(text) {
			flags = rFlags.FindStringSubmatch(text)[1]
		} else if rMntID.MatchString(text) {
			mntid = rMntID.FindStringSubmatch(text)[1]
		} else if rInotify.MatchString(text) {
			newInotify, err := parseInotifyInfo(text)
			if err != nil {
				return nil, err
			}
			inotify = append(inotify, *newInotify)
		}
	}

	i := &ProcFDInfo{
		FD:           fd,
		Pos:          pos,
		Flags:        flags,
		MntID:        mntid,
		InotifyInfos: inotify,
	}

	return i, nil
}

// InotifyInfo represents a single inotify line in the fdinfo file.
type InotifyInfo struct {
	// Watch descriptor number
	WD string
	// Inode number
	Ino string
	// Device ID
	Sdev string
	// Mask of events being monitored
	Mask string
}

// InotifyInfo constructor. Only available on kernel 3.8+.
func parseInotifyInfo(line string) (*InotifyInfo, error) {
	m := rInotifyParts.FindStringSubmatch(line)
	if len(m) >= 4 {
		var mask string
		if len(m) == 5 {
			mask = m[4]
		}
		i := &InotifyInfo{
			WD:   m[1],
			Ino:  m[2],
			Sdev: m[3],
			Mask: mask,
		}
		return i, nil
	}
	return nil, errors.New("invalid inode entry: " + line)
}

// ProcFDInfos represents a list of ProcFDInfo structs.
type ProcFDInfos []ProcFDInfo

func (p ProcFDInfos) Len() int           { return len(p) }
func (p ProcFDInfos) Swap(i, j int)      { p[i], p[j] = p[j], p[i] }
func (p ProcFDInfos) Less(i, j int) bool { return p[i].FD < p[j].FD }

// InotifyWatchLen returns the total number of inotify watches
func (p ProcFDInfos) InotifyWatchLen() (int, error) {
	length := 0
	for _, f := range p {
		length += len(f.InotifyInfos)
	}

	return length, nil
}