1// Copyright 2016 The Go Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style
3// license that can be found in the LICENSE file.
4
5package unix
6
7import (
8 "errors"
9 "fmt"
10 "strconv"
11)
12
13// Pledge implements the pledge syscall.
14//
15// This changes both the promises and execpromises; use PledgePromises or
16// PledgeExecpromises to only change the promises or execpromises
17// respectively.
18//
19// For more information see pledge(2).
20func Pledge(promises, execpromises string) error {
21 if err := pledgeAvailable(); err != nil {
22 return err
23 }
24
25 pptr, err := BytePtrFromString(promises)
26 if err != nil {
27 return err
28 }
29
30 exptr, err := BytePtrFromString(execpromises)
31 if err != nil {
32 return err
33 }
34
35 return pledge(pptr, exptr)
36}
37
38// PledgePromises implements the pledge syscall.
39//
40// This changes the promises and leaves the execpromises untouched.
41//
42// For more information see pledge(2).
43func PledgePromises(promises string) error {
44 if err := pledgeAvailable(); err != nil {
45 return err
46 }
47
48 pptr, err := BytePtrFromString(promises)
49 if err != nil {
50 return err
51 }
52
53 return pledge(pptr, nil)
54}
55
56// PledgeExecpromises implements the pledge syscall.
57//
58// This changes the execpromises and leaves the promises untouched.
59//
60// For more information see pledge(2).
61func PledgeExecpromises(execpromises string) error {
62 if err := pledgeAvailable(); err != nil {
63 return err
64 }
65
66 exptr, err := BytePtrFromString(execpromises)
67 if err != nil {
68 return err
69 }
70
71 return pledge(nil, exptr)
72}
73
74// majmin returns major and minor version number for an OpenBSD system.
75func majmin() (major int, minor int, err error) {
76 var v Utsname
77 err = Uname(&v)
78 if err != nil {
79 return
80 }
81
82 major, err = strconv.Atoi(string(v.Release[0]))
83 if err != nil {
84 err = errors.New("cannot parse major version number returned by uname")
85 return
86 }
87
88 minor, err = strconv.Atoi(string(v.Release[2]))
89 if err != nil {
90 err = errors.New("cannot parse minor version number returned by uname")
91 return
92 }
93
94 return
95}
96
97// pledgeAvailable checks for availability of the pledge(2) syscall
98// based on the running OpenBSD version.
99func pledgeAvailable() error {
100 maj, min, err := majmin()
101 if err != nil {
102 return err
103 }
104
105 // Require OpenBSD 6.4 as a minimum.
106 if maj < 6 || (maj == 6 && min <= 3) {
107 return fmt.Errorf("cannot call Pledge on OpenBSD %d.%d", maj, min)
108 }
109
110 return nil
111}