summaryrefslogtreecommitdiff
path: root/src/runtime/env_plan9.go
blob: 76e9867e030a5fea9fbdae6a56ea0dc212dfe821 (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
// Copyright 2012 The Go Authors.  All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package runtime

import "unsafe"

func getenv(s *byte) *byte {
	val := gogetenv(gostringnocopy(s))
	if val == "" {
		return nil
	}
	// Strings found in environment are NUL-terminated.
	return &bytes(val)[0]
}

var tracebackbuf [128]byte

func gogetenv(key string) string {
	var file [128]byte
	if len(key) > len(file)-6 {
		return ""
	}

	copy(file[:], "/env/")
	copy(file[5:], key)

	fd := open(&file[0], _OREAD, 0)
	if fd < 0 {
		return ""
	}
	n := seek(fd, 0, 2) - 1
	if n <= 0 {
		close(fd)
		return ""
	}

	p := make([]byte, n)

	r := pread(fd, unsafe.Pointer(&p[0]), int32(n), 0)
	close(fd)
	if r < 0 {
		return ""
	}

	var s string
	sp := (*_string)(unsafe.Pointer(&s))
	sp.str = &p[0]
	sp.len = int(r)
	return s
}