1 files changed, 76 insertions, 0 deletions
diff --git a/src/runtime/env_posix.go b/src/runtime/env_posix.go
new file mode 100644
index 0000000..af353bb
--- /dev/null
+++ b/src/runtime/env_posix.go
@@ -0,0 +1,76 @@
+// 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 aix darwin dragonfly freebsd js,wasm linux netbsd openbsd solaris windows plan9
+
+package runtime
+
+import "unsafe"
+
+func gogetenv(key string) string {
+	env := environ()
+	if env == nil {
+		throw("getenv before env init")
+	}
+	for _, s := range env {
+		if len(s) > len(key) && s[len(key)] == '=' && envKeyEqual(s[:len(key)], key) {
+			return s[len(key)+1:]
+		}
+	}
+	return ""
+}
+
+// envKeyEqual reports whether a == b, with ASCII-only case insensitivity
+// on Windows. The two strings must have the same length.
+func envKeyEqual(a, b string) bool {
+	if GOOS == "windows" { // case insensitive
+		for i := 0; i < len(a); i++ {
+			ca, cb := a[i], b[i]
+			if ca == cb || lowerASCII(ca) == lowerASCII(cb) {
+				continue
+			}
+			return false
+		}
+		return true
+	}
+	return a == b
+}
+
+func lowerASCII(c byte) byte {
+	if 'A' <= c && c <= 'Z' {
+		return c + ('a' - 'A')
+	}
+	return c
+}
+
+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(_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(_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])
+}