From 0d682e24a1ba8e93e5e54a73d64f7d256f87492f Mon Sep 17 00:00:00 2001
From: Kir Kolyshkin <kolyshkin@gmail.com>
Date: Tue, 28 Nov 2017 17:49:39 -0800
Subject: [PATCH] plugins: don't compile for static build
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We can't really use `dlopen()` from a statically built binary, so
let's disable this functionality if `static_build` tag is used
(which is sort of a de-facto standard way of doing it).

This eliminates the following warning:

	🇩 bin/containerd
	# github.com/containerd/containerd/cmd/containerd
	/tmp/go-link-509179974/000004.o: In function `pluginOpen':
	/usr/local/go/src/plugin/plugin_dlopen.go:19: warning: Using 'dlopen' in
	statically linked applications requires at runtime the shared libraries
	from the glibc version used for linking

[v2: add static build instructions to BUILDING.md]

Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
---
 BUILDING.md            | 14 ++++++++++++++
 plugin/plugin_go18.go  |  2 +-
 plugin/plugin_other.go |  2 +-
 3 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/BUILDING.md b/BUILDING.md
index 9594fdfe4..327d0aaf8 100644
--- a/BUILDING.md
+++ b/BUILDING.md
@@ -43,6 +43,20 @@ You can move them in your global path with:
 sudo make install
 ```
 
+### Static binaries
+
+You can build static binaries by providing a few variables to `make`:
+
+```sudo
+make	EXTRA_FLAGS="-buildmode pie" \
+	EXTRA_LDFLAGS='-extldflags "-fno-PIC -static"' \
+	BUILDTAGS="static_build"
+```
+
+Note that
+ - static build is discouraged
+ - static containerd binary does not support plugins loading
+
 ## Via Docker Container
 
 ### Build containerd
diff --git a/plugin/plugin_go18.go b/plugin/plugin_go18.go
index d9101246e..eee0e3fdb 100644
--- a/plugin/plugin_go18.go
+++ b/plugin/plugin_go18.go
@@ -1,4 +1,4 @@
-// +build go1.8,!windows,amd64
+// +build go1.8,!windows,amd64,!static_build
 
 package plugin
 
diff --git a/plugin/plugin_other.go b/plugin/plugin_other.go
index 21a457040..180917af8 100644
--- a/plugin/plugin_other.go
+++ b/plugin/plugin_other.go
@@ -1,4 +1,4 @@
-// +build !go1.8 windows !amd64
+// +build !go1.8 windows !amd64 static_build
 
 package plugin