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
|
// 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 dev
import (
"os"
"strings"
"syscall"
)
// TTY represents a tty including its minor and major device number and the
// path to the tty.
type TTY struct {
// Minor device number.
Minor uint64
// Major device number.
Major uint64
// Path to the tty device.
Path string
}
// FindTTY return the corresponding TTY to the ttyNr or nil of non could be
// found.
func FindTTY(ttyNr uint64, devices *[]TTY) (*TTY, error) {
// (man 5 proc) The minor device number is contained in the combination
// of bits 31 to 20 and 7 to 0; the major device number is in bits 15
// to 8.
maj := (ttyNr >> 8) & 0xFF
min := (ttyNr & 0xFF) | ((ttyNr >> 20) & 0xFFF)
if devices == nil {
devs, err := TTYs()
if err != nil {
return nil, err
}
devices = devs
}
for _, t := range *devices {
if t.Minor == min && t.Major == maj {
return &t, nil
}
}
return nil, nil
}
// majDevNum returns the major device number of rdev (see stat_t.Rdev).
func majDevNum(rdev uint64) uint64 {
return (rdev >> 8) & 0xfff
}
// minDevNum returns the minor device number of rdev (see stat_t.Rdev).
func minDevNum(rdev uint64) uint64 {
return (rdev & 0xff) | ((rdev >> 12) & 0xfff00)
}
// TTYs parses /dev for tty and pts devices.
func TTYs() (*[]TTY, error) {
devDir, err := os.Open("/dev/")
if err != nil {
return nil, err
}
defer devDir.Close()
devices := []string{}
devTTYs, err := devDir.Readdirnames(0)
if err != nil {
return nil, err
}
for _, d := range devTTYs {
if !strings.HasPrefix(d, "tty") {
continue
}
devices = append(devices, "/dev/"+d)
}
devPTSDir, err := os.Open("/dev/pts/")
if err != nil {
return nil, err
}
defer devPTSDir.Close()
devPTSs, err := devPTSDir.Readdirnames(0)
if err != nil {
return nil, err
}
for _, d := range devPTSs {
devices = append(devices, "/dev/pts/"+d)
}
ttys := []TTY{}
for _, dev := range devices {
fi, err := os.Stat(dev)
if err != nil {
if os.IsNotExist(err) {
// catch race conditions
continue
}
return nil, err
}
s := fi.Sys().(*syscall.Stat_t)
t := TTY{
Minor: minDevNum(s.Rdev),
Major: majDevNum(s.Rdev),
Path: dev,
}
ttys = append(ttys, t)
}
return &ttys, nil
}
|
