cmd/dist: log OS version when testing

As a follow-up to https://golang.org/cl/371474, add the OS version to
the metadata printed for each test.

Fixes #50146.

Change-Id: I3b7e47983d0e85feebce8e424881b931882d53bf
Reviewed-on: https://go-review.googlesource.com/c/go/+/371475
Reviewed-by: Bryan Mills <bcmills@google.com>
Trust: Michael Pratt <mpratt@google.com>
Run-TryBot: Michael Pratt <mpratt@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>

1 files changed, 36 insertions, 0 deletions

diff --git a/src/cmd/internal/osinfo/os_unix.go b/src/cmd/internal/osinfo/os_unix.go
new file mode 100644
index 0000000000..4587cb2501
--- /dev/null
+++ b/src/cmd/internal/osinfo/os_unix.go
@@ -0,0 +1,36 @@
+// Copyright 2021 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.
+
+//go:build aix || darwin || dragonfly || freebsd || linux || netbsd || openbsd || solaris
+
+package osinfo
+
+import (
+	"bytes"
+
+	"golang.org/x/sys/unix"
+)
+
+func utsString(b []byte) string {
+	i := bytes.IndexByte(b, 0)
+	if i == -1 {
+		return string(b)
+	}
+	return string(b[:i])
+}
+
+// Version returns the OS version name/number.
+func Version() (string, error) {
+	var uts unix.Utsname
+	if err := unix.Uname(&uts); err != nil {
+		return "", err
+	}
+
+	sysname := utsString(uts.Sysname[:])
+	release := utsString(uts.Release[:])
+	version := utsString(uts.Version[:])
+	machine := utsString(uts.Machine[:])
+
+	return sysname + " " + release + " " + version + " " + machine, nil
+}