mirror of https://github.com/golang/go.git
55 lines
1.5 KiB
Go
55 lines
1.5 KiB
Go
// Copyright 2012 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// +build darwin dragonfly freebsd linux nacl netbsd openbsd solaris windows
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package runtime
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import "unsafe"
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func gogetenv(key string) string {
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env := environ()
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if env == nil {
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throw("getenv before env init")
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}
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for _, s := range environ() {
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if len(s) > len(key) && s[len(key)] == '=' && s[:len(key)] == key {
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return s[len(key)+1:]
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}
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}
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return ""
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}
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var _cgo_setenv unsafe.Pointer // pointer to C function
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var _cgo_unsetenv unsafe.Pointer // pointer to C function
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// Update the C environment if cgo is loaded.
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// Called from syscall.Setenv.
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//go:linkname syscall_setenv_c syscall.setenv_c
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func syscall_setenv_c(k string, v string) {
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if _cgo_setenv == nil {
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return
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}
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arg := [2]unsafe.Pointer{cstring(k), cstring(v)}
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asmcgocall(unsafe.Pointer(_cgo_setenv), unsafe.Pointer(&arg))
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}
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// Update the C environment if cgo is loaded.
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// Called from syscall.unsetenv.
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//go:linkname syscall_unsetenv_c syscall.unsetenv_c
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func syscall_unsetenv_c(k string) {
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if _cgo_unsetenv == nil {
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return
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}
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arg := [1]unsafe.Pointer{cstring(k)}
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asmcgocall(unsafe.Pointer(_cgo_unsetenv), unsafe.Pointer(&arg))
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}
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func cstring(s string) unsafe.Pointer {
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p := make([]byte, len(s)+1)
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sp := (*_string)(unsafe.Pointer(&s))
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memmove(unsafe.Pointer(&p[0]), unsafe.Pointer(sp.str), uintptr(len(s)))
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return unsafe.Pointer(&p[0])
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}
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