From 6c5f2993c210854b077ad07c9a94334f8c82fbb1 Mon Sep 17 00:00:00 2001
From: Tianon Gravi <admwiggin@gmail.com>
Date: Mon, 9 Jan 2017 10:10:49 -0800
Subject: [PATCH] Add an explicit Alpine 3.5 variant of Go 1.7

---
 .travis.yml                   |  1 +
 1.7/alpine3.5/17847.patch     | 33 ++++++++++++
 1.7/alpine3.5/Dockerfile      | 42 +++++++++++++++
 1.7/alpine3.5/go-wrapper      | 97 +++++++++++++++++++++++++++++++++++
 1.7/alpine3.5/no-pic.patch    | 16 ++++++
 generate-stackbrew-library.sh |  2 +-
 update.sh                     |  4 +-
 7 files changed, 192 insertions(+), 3 deletions(-)
 create mode 100644 1.7/alpine3.5/17847.patch
 create mode 100644 1.7/alpine3.5/Dockerfile
 create mode 100755 1.7/alpine3.5/go-wrapper
 create mode 100644 1.7/alpine3.5/no-pic.patch

diff --git a/.travis.yml b/.travis.yml
index e632e5e8..9157197f 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -8,6 +8,7 @@ env:
   - VERSION=1.7 VARIANT=
   - VERSION=1.7 VARIANT=wheezy
   - VERSION=1.7 VARIANT=alpine
+  - VERSION=1.7 VARIANT=alpine3.5
   - VERSION=1.6 VARIANT=
   - VERSION=1.6 VARIANT=wheezy
   - VERSION=1.6 VARIANT=alpine
diff --git a/1.7/alpine3.5/17847.patch b/1.7/alpine3.5/17847.patch
new file mode 100644
index 00000000..de9c7537
--- /dev/null
+++ b/1.7/alpine3.5/17847.patch
@@ -0,0 +1,33 @@
+diff --git a/src/cmd/link/internal/ld/lib.go b/src/cmd/link/internal/ld/lib.go
+index 14f4fa9..bf2de57 100644
+--- a/src/cmd/link/internal/ld/lib.go
++++ b/src/cmd/link/internal/ld/lib.go
+@@ -1251,6 +1251,28 @@ func hostlink() {
+ 		}
+ 	}
+ 
++	// When building a program with the default -buildmode=exe the
++	// gc compiler generates code requires DT_TEXTREL in a
++	// position independent executable (PIE). On systems where the
++	// toolchain creates PIEs by default, and where DT_TEXTREL
++	// does not work, the resulting programs will not run. See
++	// issue #17847. To avoid this problem pass -no-pie to the
++	// toolchain if it is supported.
++	if Buildmode == BuildmodeExe {
++		src := filepath.Join(tmpdir, "trivial.c")
++		if err := ioutil.WriteFile(src, []byte{}, 0666); err != nil {
++			Ctxt.Diag("WriteFile trivial.c failed: %v", err)
++		}
++		cmd := exec.Command(argv[0], "-c", "-no-pie", "trivial.c")
++		cmd.Dir = tmpdir
++		cmd.Env = append([]string{"LC_ALL=C"}, os.Environ()...)
++		out, err := cmd.CombinedOutput()
++		supported := err == nil && !bytes.Contains(out, []byte("unrecognized"))
++		if supported {
++			argv = append(argv, "-no-pie")
++		}
++	}
++
+ 	for _, p := range strings.Fields(extldflags) {
+ 		argv = append(argv, p)
+ 
diff --git a/1.7/alpine3.5/Dockerfile b/1.7/alpine3.5/Dockerfile
new file mode 100644
index 00000000..d7dd02a2
--- /dev/null
+++ b/1.7/alpine3.5/Dockerfile
@@ -0,0 +1,42 @@
+FROM alpine:3.5
+
+RUN apk add --no-cache ca-certificates
+
+ENV GOLANG_VERSION 1.7.4
+ENV GOLANG_SRC_URL https://golang.org/dl/go$GOLANG_VERSION.src.tar.gz
+ENV GOLANG_SRC_SHA256 4c189111e9ba651a2bb3ee868aa881fab36b2f2da3409e80885ca758a6b614cc
+
+# https://golang.org/issue/14851
+COPY no-pic.patch /
+# https://golang.org/issue/17847
+COPY 17847.patch /
+
+RUN set -ex \
+	&& apk add --no-cache --virtual .build-deps \
+		bash \
+		gcc \
+		musl-dev \
+		openssl \
+		go \
+	\
+	&& export GOROOT_BOOTSTRAP="$(go env GOROOT)" \
+	\
+	&& wget -q "$GOLANG_SRC_URL" -O golang.tar.gz \
+	&& echo "$GOLANG_SRC_SHA256  golang.tar.gz" | sha256sum -c - \
+	&& tar -C /usr/local -xzf golang.tar.gz \
+	&& rm golang.tar.gz \
+	&& cd /usr/local/go/src \
+	&& patch -p2 -i /no-pic.patch \
+	&& patch -p2 -i /17847.patch \
+	&& ./make.bash \
+	\
+	&& rm -rf /*.patch \
+	&& apk del .build-deps
+
+ENV GOPATH /go
+ENV PATH $GOPATH/bin:/usr/local/go/bin:$PATH
+
+RUN mkdir -p "$GOPATH/src" "$GOPATH/bin" && chmod -R 777 "$GOPATH"
+WORKDIR $GOPATH
+
+COPY go-wrapper /usr/local/bin/
diff --git a/1.7/alpine3.5/go-wrapper b/1.7/alpine3.5/go-wrapper
new file mode 100755
index 00000000..b63e20b4
--- /dev/null
+++ b/1.7/alpine3.5/go-wrapper
@@ -0,0 +1,97 @@
+#!/bin/sh
+set -e
+
+usage() {
+	base="$(basename "$0")"
+	cat <<EOUSAGE
+
+usage: $base command [args]
+
+This script assumes that is is run from the root of your Go package (for
+example, "/go/src/app" if your GOPATH is set to "/go").
+
+In Go 1.4, a feature was introduced to supply the canonical "import path" for a
+given package in a comment attached to a package statement
+(https://golang.org/s/go14customimport).
+
+This script allows us to take a generic directory of Go source files such as
+"/go/src/app" and determine that the canonical "import path" of where that code
+expects to live and reference itself is "github.com/jsmith/my-cool-app".  It
+will then ensure that "/go/src/github.com/jsmith/my-cool-app" is a symlink to
+"/go/src/app", which allows us to build and run it under the proper package
+name.
+
+For compatibility with versions of Go older than 1.4, the "import path" may also
+be placed in a file named ".godir".
+
+Available Commands:
+
+  $base download
+  $base download -u
+    (equivalent to "go get -d [args] [godir]")
+
+  $base install
+  $base install -race
+    (equivalent to "go install [args] [godir]")
+
+  $base run
+  $base run -app -specific -arguments
+    (assumes "GOPATH/bin" is in "PATH")
+
+EOUSAGE
+}
+
+# make sure there is a subcommand specified
+if [ "$#" -eq 0 ]; then
+	usage >&2
+	exit 1
+fi
+# "shift" so that "$@" becomes the remaining arguments and can be passed along to other "go" subcommands easily
+cmd="$1"
+shift
+
+goDir="$(go list -e -f '{{.ImportComment}}' 2>/dev/null || true)"
+
+if [ -z "$goDir" -a -s .godir ]; then
+	goDir="$(cat .godir)"
+fi
+
+dir="$(pwd -P)"
+if [ "$goDir" ]; then
+	goPath="${GOPATH%%:*}" # this just grabs the first path listed in GOPATH, if there are multiple (which is the detection logic "go get" itself uses, too)
+	goDirPath="$goPath/src/$goDir"
+	mkdir -p "$(dirname "$goDirPath")"
+	if [ ! -e "$goDirPath" ]; then
+		ln -sfv "$dir" "$goDirPath"
+	elif [ ! -L "$goDirPath" ]; then
+		echo >&2 "error: $goDirPath already exists but is unexpectedly not a symlink!"
+		exit 1
+	fi
+	goBin="$goPath/bin/$(basename "$goDir")"
+else
+	goBin="$(basename "$dir")" # likely "app"
+fi
+
+case "$cmd" in
+	download)
+		set -- go get -v -d "$@"
+		if [ "$goDir" ]; then set -- "$@" "$goDir"; fi
+		set -x; exec "$@"
+		;;
+		
+	install)
+		set -- go install -v "$@"
+		if [ "$goDir" ]; then set -- "$@" "$goDir"; fi
+		set -x; exec "$@"
+		;;
+		
+	run)
+		set -x; exec "$goBin" "$@"
+		;;
+		
+	*)
+		echo >&2 'error: unknown command:' "$cmd"
+		usage >&2
+		exit 1
+		;;
+esac
diff --git a/1.7/alpine3.5/no-pic.patch b/1.7/alpine3.5/no-pic.patch
new file mode 100644
index 00000000..b10f2905
--- /dev/null
+++ b/1.7/alpine3.5/no-pic.patch
@@ -0,0 +1,16 @@
+diff --git a/src/cmd/link/internal/ld/lib.go b/src/cmd/link/internal/ld/lib.go
+index 14f4fa9..5599307 100644
+--- a/src/cmd/link/internal/ld/lib.go
++++ b/src/cmd/link/internal/ld/lib.go
+@@ -1272,6 +1272,11 @@ func hostlink() {
+ 		argv = append(argv, peimporteddlls()...)
+ 	}
+ 
++	// The Go linker does not currently support building PIE
++	// executables when using the external linker. See:
++	// https://github.com/golang/go/issues/6940
++	argv = append(argv, "-fno-PIC")
++
+ 	if Debug['v'] != 0 {
+ 		fmt.Fprintf(Bso, "host link:")
+ 		for _, v := range argv {
diff --git a/generate-stackbrew-library.sh b/generate-stackbrew-library.sh
index 39333688..0763e1ea 100755
--- a/generate-stackbrew-library.sh
+++ b/generate-stackbrew-library.sh
@@ -69,7 +69,7 @@ for version in "${versions[@]}"; do
 	EOE
 
 	for v in \
-		onbuild wheezy alpine \
+		onbuild wheezy alpine alpine3.5 \
 		windows/windowsservercore windows/nanoserver \
 	; do
 		dir="$version/$v"
diff --git a/update.sh b/update.sh
index 58f3c533..4254ffcc 100755
--- a/update.sh
+++ b/update.sh
@@ -49,9 +49,9 @@ for version in "${versions[@]}"; do
 			"$version/"*"/Dockerfile"
 		cp go-wrapper "$version/"
 	)
-	for variant in alpine wheezy; do
+	for variant in alpine3.5 alpine wheezy; do
 		if [ -d "$version/$variant" ]; then
-			if [ "$variant" != 'alpine' ]; then
+			if [[ "$variant" != 'alpine'* ]]; then
 				(
 					set -x
 					sed 's/^FROM .*/FROM buildpack-deps:'"$variant"'-scm/' "$version/Dockerfile" > "$version/$variant/Dockerfile"