From 16939f0d56e4543a5f9e3f9295a806029e8d45d0 Mon Sep 17 00:00:00 2001
From: Brad Fitzpatrick <bradfitz@tailscale.com>
Date: Sun, 11 Sep 2022 21:45:08 -0700
Subject: [PATCH] hostinfo: detect being run in a container in more ways

Change-Id: I038ff7705ba232e6cf8dcc9775357ef708d43762
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
---
 hostinfo/hostinfo.go | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/hostinfo/hostinfo.go b/hostinfo/hostinfo.go
index ca9ea718b..d7f239e7c 100644
--- a/hostinfo/hostinfo.go
+++ b/hostinfo/hostinfo.go
@@ -229,6 +229,15 @@ func inContainer() opt.Bool {
 	}
 	var ret opt.Bool
 	ret.Set(false)
+	if _, err := os.Stat("/.dockerenv"); err == nil {
+		ret.Set(true)
+		return ret
+	}
+	if _, err := os.Stat("/run/.containerenv"); err == nil {
+		// See https://github.com/cri-o/cri-o/issues/5461
+		ret.Set(true)
+		return ret
+	}
 	lineread.File("/proc/1/cgroup", func(line []byte) error {
 		if mem.Contains(mem.B(line), mem.S("/docker/")) ||
 			mem.Contains(mem.B(line), mem.S("/lxc/")) {