release/dist/qnap: add qnap target builder

Creates new QNAP builder target, which builds go binaries then uses
docker to build into QNAP packages. Much of the docker/script code
here is pulled over from https://github.com/tailscale/tailscale-qpkg,
with adaptation into our builder structures.

The qnap/Tailscale folder contains static resources needed to build
Tailscale qpkg packages, and is an exact copy of the existing folder
in the tailscale-qpkg repo.

Builds can be run with:
```
sudo ./tool/go run ./cmd/dist build qnap
```

Updates tailscale/tailscale-qpkg#135

Signed-off-by: Sonia Appasamy <sonia@tailscale.com>

cmd/dist/dist.go

@@ -13,6 +13,7 @@ import (
 
 	"tailscale.com/release/dist"
 	"tailscale.com/release/dist/cli"
+	"tailscale.com/release/dist/qnap"
 	"tailscale.com/release/dist/synology"
 	"tailscale.com/release/dist/unixpkgs"
 )
@@ -37,6 +38,7 @@ func getTargets() ([]dist.Target, error) {
 	// To build for package center, run
 	// ./tool/go run ./cmd/dist build --synology-package-center synology
 	ret = append(ret, synology.Targets(synologyPackageCenter, nil)...)
+	ret = append(ret, qnap.Targets(nil)...)
 	return ret, nil
 }
 

release/dist/dist.go

@@ -88,6 +88,8 @@ type Build struct {
 	// number of CPU cores, which empirically keeps the builder responsive
 	// without impacting overall build time.
 	goBuildLimit chan struct{}
+
+	onCloseFuncs []func() error // funcs to be called when Builder is closed
 }
 
 // NewBuild creates a new Build rooted at repo, and writing artifacts to out.
@@ -126,9 +128,21 @@ func NewBuild(repo, out string) (*Build, error) {
 	return b, nil
 }
 
-// Close ends the build and cleans up temporary files.
+func (b *Build) AddOnCloseFunc(f func() error) {
+	b.onCloseFuncs = append(b.onCloseFuncs, f)
+}
+
+// Close ends the build, cleans up temporary files,
+// and runs any onCloseFuncs.
 func (b *Build) Close() error {
-	return os.RemoveAll(b.Tmp)
+	var errs []error
+	errs = append(errs, os.RemoveAll(b.Tmp))
+	if b.onCloseFuncs != nil {
+		for _, f := range b.onCloseFuncs {
+			errs = append(errs, f())
+		}
+	}
+	return errors.Join(errs...)
 }
 
 // Build builds all targets concurrently.

release/dist/qnap/Dockerfile.qpkg

@@ -0,0 +1,9 @@
+FROM ubuntu:20.04
+
+RUN apt-get update -y && \
+    apt-get install -y --no-install-recommends \
+    git-core \
+    ca-certificates
+RUN git clone https://github.com/qnap-dev/QDK.git
+RUN cd /QDK && ./InstallToUbuntu.sh install
+ENV PATH="/usr/share/QDK/bin:${PATH}"

release/dist/qnap/Tailscale/build_sign.csv

@@ -0,0 +1 @@
+,/Tailscale.sh,

release/dist/qnap/Tailscale/package_routines

@@ -0,0 +1,143 @@
+######################################################################
+# List of available definitions (it's not necessary to uncomment them)
+######################################################################
+###### Command definitions #####
+#CMD_AWK="/bin/awk"
+#CMD_CAT="/bin/cat"
+#CMD_CHMOD="/bin/chmod"
+#CMD_CHOWN="/bin/chown"
+#CMD_CP="/bin/cp"
+#CMD_CUT="/bin/cut"
+#CMD_DATE="/bin/date"
+#CMD_ECHO="/bin/echo"
+#CMD_EXPR="/usr/bin/expr"
+#CMD_FIND="/usr/bin/find"
+#CMD_GETCFG="/sbin/getcfg"
+#CMD_GREP="/bin/grep"
+#CMD_GZIP="/bin/gzip"
+#CMD_HOSTNAME="/bin/hostname"
+#CMD_LN="/bin/ln"
+#CMD_LOG_TOOL="/sbin/log_tool"
+#CMD_MD5SUM="/bin/md5sum"
+#CMD_MKDIR="/bin/mkdir"
+#CMD_MV="/bin/mv"
+#CMD_RM="/bin/rm"
+#CMD_RMDIR="/bin/rmdir"
+#CMD_SED="/bin/sed"
+#CMD_SETCFG="/sbin/setcfg"
+#CMD_SLEEP="/bin/sleep"
+#CMD_SORT="/usr/bin/sort"
+#CMD_SYNC="/bin/sync"
+#CMD_TAR="/bin/tar"
+#CMD_TOUCH="/bin/touch"
+#CMD_WGET="/usr/bin/wget"
+#CMD_WLOG="/sbin/write_log"
+#CMD_XARGS="/usr/bin/xargs"
+#CMD_7Z="/usr/local/sbin/7z"
+#
+###### System definitions #####
+#SYS_EXTRACT_DIR="$(pwd)"
+#SYS_CONFIG_DIR="/etc/config"
+#SYS_INIT_DIR="/etc/init.d"
+#SYS_STARTUP_DIR="/etc/rcS.d"
+#SYS_SHUTDOWN_DIR="/etc/rcK.d"
+#SYS_RSS_IMG_DIR="/home/httpd/RSS/images"
+#SYS_QPKG_DATA_FILE_GZIP="./data.tar.gz"
+#SYS_QPKG_DATA_FILE_BZIP2="./data.tar.bz2"
+#SYS_QPKG_DATA_FILE_7ZIP="./data.tar.7z"
+#SYS_QPKG_DATA_CONFIG_FILE="./conf.tar.gz"
+#SYS_QPKG_DATA_MD5SUM_FILE="./md5sum"
+#SYS_QPKG_DATA_PACKAGES_FILE="./Packages.gz"
+#SYS_QPKG_CONFIG_FILE="$SYS_CONFIG_DIR/qpkg.conf"
+#SYS_QPKG_CONF_FIELD_QPKGFILE="QPKG_File"
+#SYS_QPKG_CONF_FIELD_NAME="Name"
+#SYS_QPKG_CONF_FIELD_VERSION="Version"
+#SYS_QPKG_CONF_FIELD_ENABLE="Enable"
+#SYS_QPKG_CONF_FIELD_DATE="Date"
+#SYS_QPKG_CONF_FIELD_SHELL="Shell"
+#SYS_QPKG_CONF_FIELD_INSTALL_PATH="Install_Path"
+#SYS_QPKG_CONF_FIELD_CONFIG_PATH="Config_Path"
+#SYS_QPKG_CONF_FIELD_WEBUI="WebUI"
+#SYS_QPKG_CONF_FIELD_WEBPORT="Web_Port"
+#SYS_QPKG_CONF_FIELD_SERVICEPORT="Service_Port"
+#SYS_QPKG_CONF_FIELD_SERVICE_PIDFILE="Pid_File"
+#SYS_QPKG_CONF_FIELD_AUTHOR="Author"
+#SYS_QPKG_CONF_FIELD_RC_NUMBER="RC_Number"
+## The following variables are assigned values at run-time.
+#SYS_HOSTNAME=$($CMD_HOSTNAME)
+## Data file name (one of SYS_QPKG_DATA_FILE_GZIP, SYS_QPKG_DATA_FILE_BZIP2,
+## or SYS_QPKG_DATA_FILE_7ZIP)
+#SYS_QPKG_DATA_FILE=
+## Base location.
+#SYS_QPKG_BASE=""
+## Base location of QPKG installed packages.
+#SYS_QPKG_INSTALL_PATH=""
+## Location of installed software.
+#SYS_QPKG_DIR=""
+## If the QPKG should be enabled or disabled after the installation/upgrade.
+#SYS_QPKG_SERVICE_ENABLED=""
+## Architecture of the device the QPKG is installed on.
+#SYS_CPU_ARCH=""
+## Name and location of system shares
+#SYS_PUBLIC_SHARE=""
+#SYS_PUBLIC_PATH=""
+#SYS_DOWNLOAD_SHARE=""
+#SYS_DOWNLOAD_PATH=""
+#SYS_MULTIMEDIA_SHARE=""
+#SYS_MULTIMEDIA_PATH=""
+#SYS_RECORDINGS_SHARE=""
+#SYS_RECORDINGS_PATH=""
+#SYS_USB_SHARE=""
+#SYS_USB_PATH=""
+#SYS_WEB_SHARE=""
+#SYS_WEB_PATH=""
+## Path to ipkg or opkg package tool if installed.
+#CMD_PKG_TOOL=
+#
+######################################################################
+# All package specific functions shall call 'err_log MSG' if an error
+# is detected that shall terminate the installation.
+######################################################################
+#
+######################################################################
+# Define any package specific operations that shall be performed when
+# the package is removed.
+######################################################################
+#PKG_PRE_REMOVE="{
+#}"
+#
+#PKG_MAIN_REMOVE="{
+#}"
+#
+PKG_POST_REMOVE="{
+    rm -f /home/httpd/cgi-bin/qpkg/Tailscale
+    rm -rf /tmp/tailscale
+    if [ -f /etc/resolv.pre-tailscale-backup.conf ] && grep -q 100.100.100.100 /etc/resolv.conf; then
+        mv /etc/resolv.pre-tailscale-backup.conf /etc/resolv.conf
+    fi
+}"
+#
+######################################################################
+# Define any package specific initialization that shall be performed
+# before the package is installed.
+######################################################################
+#pkg_init(){
+#}
+#
+######################################################################
+# Define any package specific requirement checks that shall be
+# performed before the package is installed.
+######################################################################
+#pkg_check_requirement(){
+#}
+#
+######################################################################
+# Define any package specific operations that shall be performed when
+# the package is installed.
+######################################################################
+pkg_install(){
+    ${CMD_MKDIR} -p ${SYS_QPKG_DIR}/state
+}
+
+#pkg_post_install(){
+#}

release/dist/qnap/Tailscale/qpkg.cfg.in

@@ -0,0 +1,99 @@
+# Name of the packaged application.
+QPKG_NAME="Tailscale"
+# Name of the display application.
+#QPKG_DISPLAY_NAME=""
+# Version of the packaged application.
+QPKG_VER="$QPKG_VER"
+# Author or maintainer of the package
+QPKG_AUTHOR="Tailscale Inc."
+# License for the packaged application
+#QPKG_LICENSE=""
+# One-line description of the packaged application
+#QPKG_SUMMARY="Connect all your devices using WireGuard, without the hassle."
+
+# Preferred number in start/stop sequence.
+QPKG_RC_NUM="101"
+# Init-script used to control the start and stop of the installed application.
+QPKG_SERVICE_PROGRAM="Tailscale.sh"
+
+# Optional 1 is enable. Path of starting/ stopping shall script. (no start/stop on App Center)
+#QPKG_DISABLE_APPCENTER_UI_SERVICE=1
+
+# Specifies any packages required for the current package to operate.
+QPKG_REQUIRE=""
+# Specifies what packages cannot be installed if the current package
+# is to operate properly.
+#QPKG_CONFLICT="Python"
+# Name of configuration file (multiple definitions are allowed).
+#QPKG_CONFIG="Tailscale.cfg"
+#QPKG_CONFIG="/etc/config/myApp.conf"
+# Port number used by service program.
+QPKG_SERVICE_PORT="41641"
+# Location of file with running service's PID
+#QPKG_SERVICE_PIDFILE=""
+# Relative path to web interface
+QPKG_WEBUI="/cgi-bin/qpkg/Tailscale/index.cgi"
+# Port number for the web interface.
+#QPKG_WEB_PORT=""
+# Port number for the SSL web interface.
+#QPKG_WEB_SSL_PORT=""
+
+# Use QTS HTTP Proxy and set Proxy_Path in the qpkg.conf.
+# When the QPKG has its own HTTP service port, and want clients to connect via QTS HTTP port (default 8080).
+# Usually use this option when the QPKG need to connect via myQNAPcloud service.
+QPKG_USE_PROXY="1"
+#QPKG_PROXY_PATH="/qpkg_name"
+
+#Desktop Application (since 4.1)
+# Set value to 1 means to open the QPKG's Web UI inside QTS desktop instead of new window.
+#QPKG_DESKTOP_APP="1"
+# Desktop Application Window default inner width (since 4.1) (not over 1178)
+#QPKG_DESKTOP_APP_WIN_WIDTH=""
+# Desktop Application Window default inner height (since 4.1) (not over 600)
+#QPKG_DESKTOP_APP_WIN_HEIGHT=""
+
+# Minimum QTS version requirement
+QTS_MINI_VERSION="5.0.0"
+# Maximum QTS version requirement
+#QTS_MAX_VERSION="5.0.0"
+
+# Select volume
+# 1: support installation
+# 2: support migration
+# 3 (1+2): support both installation and migration
+QPKG_VOLUME_SELECT="1"
+
+# Set timeout for QPKG enable and QPKG disable (since 4.1.0)
+# Format in seconds (enable, disable)
+#QPKG_TIMEOUT="10,30"
+
+# Visible setting for the QPKG that has web UI, show this QPKG on the Main menu of
+# 1(default): administrators, 2: all NAS users.
+QPKG_VISIBLE="1"
+
+# Location of icons for the packaged application.
+QDK_DATA_DIR_ICONS="icons"
+# Location of files specific to arm-x19 packages.
+#QDK_DATA_DIR_X19="arm-x19"
+# Location of files specific to arm-x31 packages.
+#QDK_DATA_DIR_X31="arm-x31"
+# Location of files specific to arm-x41 packages.
+#QDK_DATA_DIR_X41="arm_al"
+# Location of files specific to x86 packages.
+#QDK_DATA_DIR_X86="x86"
+# Location of files specific to x86 (64-bit) packages.
+#QDK_DATA_DIR_X86_64="x86_64"
+# Location of files common to all architectures.
+QDK_DATA_DIR_SHARED="shared"
+# Location of configuration files.
+#QDK_DATA_DIR_CONFIG="config"
+# Name of local data package.
+#QDK_DATA_FILE=""
+# Name of extra package (multiple definitions are allowed).
+#QDK_EXTRA_FILE=""
+# For QNAP code signing (currently can be done only inside QNAP)
+# Uncomment the following four options if you want to enable code signing for this QPKG
+#QNAP_CODE_SIGNING="0"
+#QNAP_CODE_SIGNING_SERVER_IP="codesigning.qnap.com.tw"
+#QNAP_CODE_SIGNING_SERVER_PORT="5001"
+#QNAP_CODE_SIGNING_CSV="build_sign.csv"

release/dist/qnap/Tailscale/shared/Tailscale.sh

@@ -0,0 +1,50 @@
+#!/bin/sh
+CONF=/etc/config/qpkg.conf
+QPKG_NAME="Tailscale"
+QPKG_ROOT=`/sbin/getcfg ${QPKG_NAME} Install_Path -f ${CONF}`
+QPKG_PORT=`/sbin/getcfg ${QPKG_NAME} Service_Port -f ${CONF}`
+export QNAP_QPKG=${QPKG_NAME}
+set -e
+
+case "$1" in
+  start)
+    ENABLED=$(/sbin/getcfg ${QPKG_NAME} Enable -u -d FALSE -f ${CONF})
+    if [ "${ENABLED}" != "TRUE" ]; then
+        echo "${QPKG_NAME} is disabled."
+        exit 1
+    fi
+    mkdir -p /home/httpd/cgi-bin/qpkg
+    ln -sf ${QPKG_ROOT}/ui /home/httpd/cgi-bin/qpkg/${QPKG_NAME}
+    mkdir -p -m 0755 /tmp/tailscale
+    if [ -e /tmp/tailscale/tailscaled.pid ]; then
+        PID=$(cat /tmp/tailscale/tailscaled.pid)
+        if [ -d /proc/${PID}/ ]; then
+          echo "${QPKG_NAME} is already running."
+          exit 0
+        fi
+    fi
+    ${QPKG_ROOT}/tailscaled --port ${QPKG_PORT} --statedir=${QPKG_ROOT}/state --socket=/tmp/tailscale/tailscaled.sock 2> /dev/null &
+    echo $! > /tmp/tailscale/tailscaled.pid
+    ;;
+
+  stop)
+    if [ -e /tmp/tailscale/tailscaled.pid ]; then
+      PID=$(cat /tmp/tailscale/tailscaled.pid)
+      kill -9 ${PID} || true
+      rm -f /tmp/tailscale/tailscaled.pid
+    fi
+    ;;
+
+  restart)
+    $0 stop
+    $0 start
+    ;;
+  remove)
+    ;;
+
+  *)
+    echo "Usage: $0 {start|stop|restart|remove}"
+    exit 1
+esac
+
+exit 0

release/dist/qnap/Tailscale/shared/ui/.htaccess

@@ -0,0 +1,2 @@
+Options +ExecCGI
+AddHandler cgi-script .cgi

release/dist/qnap/Tailscale/shared/ui/index.cgi

@@ -0,0 +1,5 @@
+#!/bin/sh
+CONF=/etc/config/qpkg.conf
+QPKG_NAME="Tailscale"
+QPKG_ROOT=$(/sbin/getcfg ${QPKG_NAME} Install_Path -f ${CONF} -d"")
+exec "${QPKG_ROOT}/tailscale" --socket=/tmp/tailscale/tailscaled.sock web --cgi --prefix="/cgi-bin/qpkg/Tailscale/index.cgi/"

release/dist/qnap/build-qpkg.sh

@@ -0,0 +1,14 @@
+#!/bin/bash
+
+mkdir -p /Tailscale/$ARCH
+cp /tailscaled /Tailscale/$ARCH/tailscaled
+cp /tailscale /Tailscale/$ARCH/tailscale
+
+sed "s/\$QPKG_VER/$TSTAG-$QNAPTAG/g" /Tailscale/qpkg.cfg.in > /Tailscale/qpkg.cfg
+
+qbuild --root /Tailscale --build-arch $ARCH --build-dir /out
+
+# Clean up folders and files created for build.
+rm -r /Tailscale/$ARCH
+rm /Tailscale/sed*
+rm /Tailscale/qpkg.cfg

release/dist/qnap/pkgs.go

@@ -0,0 +1,188 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+// Package qnap contains dist Targets for building QNAP Tailscale packages.
+//
+// QNAP dev docs over at https://www.qnap.com/en/how-to/tutorial/article/qpkg-development-guidelines.
+package qnap
+
+import (
+	"errors"
+	"fmt"
+	"log"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"sync"
+
+	"tailscale.com/release/dist"
+)
+
+type target struct {
+	goenv  map[string]string
+	arch   string
+	signer dist.Signer
+}
+
+func (t *target) String() string {
+	return fmt.Sprintf("qnap/%s", t.arch)
+}
+
+func (t *target) Build(b *dist.Build) ([]string, error) {
+	// Stop early if we don't have docker running.
+	if _, err := exec.LookPath("docker"); err != nil {
+		return nil, fmt.Errorf("docker not found, cannot build: %w", err)
+	}
+
+	qnapBuilds := getQnapBuilds(b)
+	inner, err := qnapBuilds.buildInnerPackage(b, t.goenv)
+	if err != nil {
+		return nil, err
+	}
+
+	return t.buildQPKG(b, qnapBuilds, inner)
+}
+
+func (t *target) buildQPKG(b *dist.Build, qnapBuilds *qnapBuilds, inner *innerPkg) ([]string, error) {
+	if _, err := exec.LookPath("docker"); err != nil {
+		return nil, fmt.Errorf("docker not found, cannot build: %w", err)
+	}
+
+	if err := qnapBuilds.makeDockerImage(b); err != nil {
+		return nil, fmt.Errorf("makeDockerImage: %w", err)
+	}
+
+	qnapTag := "1" // currently static, we don't seem to bump this
+
+	filename := fmt.Sprintf("Tailscale_%s-%s_%s.qpkg", b.Version.Short, qnapTag, t.arch)
+	out := filepath.Join(b.Out, filename)
+	log.Printf("Building %s", out)
+
+	cmd := b.Command(b.Repo, "docker", "run", "--rm",
+		"-e", fmt.Sprintf("ARCH=%s", t.arch),
+		"-e", fmt.Sprintf("TSTAG=%s", b.Version.Short),
+		"-e", fmt.Sprintf("QNAPTAG=%s", qnapTag),
+		"-v", fmt.Sprintf("%s:/tailscale", inner.tsPath),
+		"-v", fmt.Sprintf("%s:/tailscaled", inner.tsdPath),
+		// Tailscale folder has QNAP package setup files needed for building.
+		"-v", fmt.Sprintf("%s:/Tailscale", filepath.Join(b.Repo, "release/dist/qnap/Tailscale")),
+		"-v", fmt.Sprintf("%s:/build-qpkg.sh", filepath.Join(b.Repo, "release/dist/qnap/build-qpkg.sh")),
+		"-v", fmt.Sprintf("%s:/out", b.Out),
+		"build.tailscale.io/qdk:latest",
+		"/build-qpkg.sh",
+	)
+	// dist.Build runs target builds in parallel goroutines by default.
+	// For QNAP, this is an issue because the underlaying qbuild builder will
+	// create tmp directories in the shared docker image that end up conflicting
+	// with one another.
+	// So we use a mutex to only allow one "docker run" at a time.
+	qnapBuilds.dockerImageMu.Lock()
+	defer qnapBuilds.dockerImageMu.Unlock()
+	if err := cmd.Run(); err != nil {
+		return nil, fmt.Errorf("docker run: %w", err)
+	}
+
+	// TODO(sonia): Use signer?
+
+	return []string{out, out + ".md5"}, nil
+}
+
+type qnapBuildsMemoizeKey struct{}
+
+type innerPkg struct {
+	tsPath  string // tailscale binary path
+	tsdPath string // tailscaled binary path
+}
+
+// qnapBuilds is extra build context shared by all qnap builds.
+type qnapBuilds struct {
+	innerPkgs     dist.Memoize[*innerPkg]
+	dockerImageMu sync.Mutex
+}
+
+// getQnapBuilds returns the qnapBuilds for b, creating one if needed.
+func getQnapBuilds(b *dist.Build) *qnapBuilds {
+	return b.Extra(qnapBuildsMemoizeKey{}, func() any { return new(qnapBuilds) }).(*qnapBuilds)
+}
+
+// buildInnerPackage builds the go binaries used for qnap packages.
+// These binaries get embedded with Tailscale package metadata to form qnap
+// releases.
+func (m *qnapBuilds) buildInnerPackage(b *dist.Build, goenv map[string]string) (*innerPkg, error) {
+	return m.innerPkgs.Do(goenv, func() (*innerPkg, error) {
+		if err := b.BuildWebClientAssets(); err != nil {
+			return nil, err
+		}
+		ts, err := b.BuildGoBinary("tailscale.com/cmd/tailscale", goenv)
+		if err != nil {
+			return nil, err
+		}
+		tsd, err := b.BuildGoBinary("tailscale.com/cmd/tailscaled", goenv)
+		if err != nil {
+			return nil, err
+		}
+
+		// The go binaries above get built and put into a /tmp directory created
+		// by b.TmpDir(). But, we build QNAP with docker, which doesn't always
+		// allow for mounting tmp directories (seemingly dependent on docker
+		// host).
+		// https://stackoverflow.com/questions/65267251/docker-bind-mount-directory-in-tmp-not-working
+		//
+		// So here, we move the binaries into a directory within the b.Repo
+		// path and clean it up when the builder closes.
+
+		tmpDir := filepath.Join(b.Repo, fmt.Sprintf("/tmp-qnap-%s-%s-%s", b.Version.Short, goenv["GOOS"], goenv["GOARCH"]))
+		if err = os.MkdirAll(tmpDir, 0755); err != nil {
+			return nil, err
+		}
+		b.AddOnCloseFunc(func() error {
+			return os.RemoveAll(tmpDir)
+		})
+
+		tsBytes, err := os.ReadFile(ts)
+		if err != nil {
+			return nil, err
+		}
+		tsdBytes, err := os.ReadFile(tsd)
+		if err != nil {
+			return nil, err
+		}
+
+		tsPath := filepath.Join(tmpDir, "tailscale")
+		if err := os.WriteFile(tsPath, tsBytes, 0755); err != nil {
+			return nil, err
+		}
+		tsdPath := filepath.Join(tmpDir, "tailscaled")
+		if err := os.WriteFile(tsdPath, tsdBytes, 0755); err != nil {
+			return nil, err
+		}
+
+		return &innerPkg{tsPath: tsPath, tsdPath: tsdPath}, nil
+	})
+}
+
+func (m *qnapBuilds) makeDockerImage(b *dist.Build) error {
+	return b.Once("make-qnap-docker-image", func() error {
+		out := "build.tailscale.io/qdk:latest"
+		var exitErr *exec.ExitError
+
+		cmd := b.Command(b.Repo, "docker", "image", "inspect", out)
+		if err := cmd.Run(); err == nil {
+			return nil // image already exists, return early
+		} else if !errors.As(err, &exitErr) {
+			return fmt.Errorf("docker image inspect: %w", err)
+		}
+
+		log.Printf("Building qnapbuilder docker image")
+
+		cmd = b.Command(b.Repo, "docker", "build",
+			"-f", filepath.Join(b.Repo, "release/dist/qnap/Dockerfile.qpkg"),
+			"-t", out,
+			filepath.Join(b.Repo, "release/dist/qnap/"),
+		)
+		if err := cmd.Run(); err != nil {
+			return fmt.Errorf("docker build: %w", err)
+		}
+		return nil
+	})
+}

release/dist/qnap/targets.go

@@ -0,0 +1,67 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+package qnap
+
+import "tailscale.com/release/dist"
+
+func Targets(signer dist.Signer) []dist.Target {
+	return []dist.Target{
+		&target{
+			arch: "x86",
+			goenv: map[string]string{
+				"GOOS":   "linux",
+				"GOARCH": "386",
+			},
+			signer: signer,
+		},
+		&target{
+			arch: "x86_ce53xx",
+			goenv: map[string]string{
+				"GOOS":   "linux",
+				"GOARCH": "386",
+			},
+			signer: signer,
+		},
+		&target{
+			arch: "x86_64",
+			goenv: map[string]string{
+				"GOOS":   "linux",
+				"GOARCH": "amd64",
+			},
+			signer: signer,
+		},
+		&target{
+			arch: "arm-x31",
+			goenv: map[string]string{
+				"GOOS":   "linux",
+				"GOARCH": "arm",
+			},
+			signer: signer,
+		},
+		&target{
+			arch: "arm-x41",
+			goenv: map[string]string{
+				"GOOS":   "linux",
+				"GOARCH": "arm",
+			},
+			signer: signer,
+		},
+		&target{
+			arch: "arm-x19",
+			goenv: map[string]string{
+				"GOOS":   "linux",
+				"GOARCH": "arm",
+			},
+			signer: signer,
+		},
+		&target{
+			arch: "arm_64",
+			goenv: map[string]string{
+				"GOOS":   "linux",
+				"GOARCH": "arm64",
+			},
+			signer: signer,
+		},
+	}
+}