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go/src/runtime/env_posix.go
Matthew Dempsky d4a7ea1b71 runtime: add stringStructOf helper function
Instead of open-coding conversions from *string to unsafe.Pointer then
to *stringStruct, add a helper function to add some type safety.
Bonus: This caught two **string values being converted to
*stringStruct in heapdump.go.

While here, get rid of the redundant _string type, but add in a
stringStructDWARF type used for generating DWARF debug info.

Change-Id: I8882f8cca66ac45190270f82019a5d85db023bd2
Reviewed-on: https://go-review.googlesource.com/16131
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2015-10-20 23:13:27 +00:00

54 lines
1.4 KiB
Go

// 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.
// +build darwin dragonfly freebsd linux nacl netbsd openbsd solaris windows
package runtime
import "unsafe"
func gogetenv(key string) string {
env := environ()
if env == nil {
throw("getenv before env init")
}
for _, s := range environ() {
if len(s) > len(key) && s[len(key)] == '=' && s[:len(key)] == key {
return s[len(key)+1:]
}
}
return ""
}
var _cgo_setenv unsafe.Pointer // pointer to C function
var _cgo_unsetenv unsafe.Pointer // pointer to C function
// Update the C environment if cgo is loaded.
// Called from syscall.Setenv.
//go:linkname syscall_setenv_c syscall.setenv_c
func syscall_setenv_c(k string, v string) {
if _cgo_setenv == nil {
return
}
arg := [2]unsafe.Pointer{cstring(k), cstring(v)}
asmcgocall(unsafe.Pointer(_cgo_setenv), unsafe.Pointer(&arg))
}
// Update the C environment if cgo is loaded.
// Called from syscall.unsetenv.
//go:linkname syscall_unsetenv_c syscall.unsetenv_c
func syscall_unsetenv_c(k string) {
if _cgo_unsetenv == nil {
return
}
arg := [1]unsafe.Pointer{cstring(k)}
asmcgocall(unsafe.Pointer(_cgo_unsetenv), unsafe.Pointer(&arg))
}
func cstring(s string) unsafe.Pointer {
p := make([]byte, len(s)+1)
copy(p, s)
return unsafe.Pointer(&p[0])
}