[dev.power64] code review 160200044: build: merge default into dev.power64

src/pkg/runtime/env_plan9.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.
+
+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
+}