WIP: support building from Windows

Signed-off-by: Jason Hall <jason@chainguard.dev>

.github/workflows/build-samples.yml

@@ -3,6 +3,7 @@ name: Build Images
 on:
   pull_request:
   push:
+  workflow_dispatch:
 
 jobs:
   build-nginx-on-all-arches:
@@ -32,23 +33,25 @@ jobs:
 
   build-all-examples-one-arch:
     name: build-all-examples-amd64
-    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        platform: [ubuntu-latest, macos-latest, windows-latest]
+    runs-on: ${{ matrix.platform }}
 
     steps:
       - uses: actions/checkout@ac593985615ec2ede58e132d2e21d2b1cbd6127c # v2.4.0
       - uses: actions/setup-go@6edd4406fa81c3da01a34fa6f6343087c207a568 # v2.1.5
         with:
           go-version: 1.19
           check-latest: true
-      - name: Setup QEMU
-        uses: docker/setup-qemu-action@v2.1.0
-
       - name: build
         run: |
           make apko
           ./apko version
 
       - name: build images
+        shell: bash
         run: |
           for cfg in $(find ./examples/ -name '*.yaml'); do
             name=$(basename ${cfg} .yaml)

pkg/apk/impl/fs/memfs.go

@@ -17,7 +17,6 @@ package fs
 import (
 	"archive/tar"
 	"bytes"
-	"encoding/binary"
 	"errors"
 	"fmt"
 	"io"
@@ -28,7 +27,6 @@ import (
 
 	"github.com/blang/vfs"
 	origMemfs "github.com/blang/vfs/memfs"
-	"golang.org/x/sys/unix"
 )
 
 const (
@@ -169,39 +167,11 @@ func (m *memFS) open(name string) (*memFile, error) {
 }
 
 func (m *memFS) Mknod(path string, mode uint32, dev int) error {
-	file, err := m.OpenFile(
-		path,
-		os.O_CREATE|os.O_WRONLY|os.O_TRUNC,
-		fs.FileMode(mode)|os.ModeCharDevice|os.ModeDevice,
-	)
-	if err != nil {
-		return err
-	}
-	defer file.Close()
-	// save the major and minor numbers in the file itself
-	devNumbers := []uint32{unix.Major(uint64(dev)), unix.Minor(uint64(dev))}
-	return binary.Write(file, binary.LittleEndian, devNumbers)
+	return m.mknod(path, mode, dev)
 }
 
 func (m *memFS) Readnod(name string) (dev int, err error) {
-	file, err := m.Open(name)
-	if err != nil {
-		return 0, err
-	}
-	defer file.Close()
-	fi, err := file.Stat()
-	if err != nil {
-		return 0, err
-	}
-	if fi.Mode()&os.ModeCharDevice != os.ModeCharDevice {
-		return 0, fmt.Errorf("%s not a character device", name)
-	}
-	// read the major and minor numbers from the file itself
-	devNumbers := make([]uint32, 2)
-	if err := binary.Read(file, binary.LittleEndian, devNumbers); err != nil {
-		return 0, err
-	}
-	return int(unix.Mkdev(devNumbers[0], devNumbers[1])), nil
+	return m.readnod(name)
 }
 
 func (m *memFS) Chmod(path string, perm fs.FileMode) error {

pkg/apk/impl/fs/rwofs_windows.go

@@ -0,0 +1,26 @@
+// Copyright 2022, 2023 Chainguard, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//  	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//go:build windows
+// +build windows
+
+package fs
+
+import "io/fs"
+
+func (f *dirFS) modeCharDevice(string, fs.FileInfo, fs.FileMode) error { return nil }
+func (f *dirFS) mknod(string, string, uint32, int) error               { return nil }
+
+func (m *memFS) mknod(string, uint32, int) error { return nil }
+func (m *memFS) readnod(string) (int, error)     { return 0, nil }

pkg/apk/impl/fs/rwosfs.go

@@ -21,10 +21,7 @@ import (
 	"path/filepath"
 	"strings"
 	"sync"
-	"syscall"
 	"time"
-
-	"golang.org/x/sys/unix"
 )
 
 type dirFSOpts struct {
@@ -142,19 +139,7 @@ func DirFS(dir string, opts ...DirFSOption) FullFS {
 				err = f.overrides.Symlink(target, path)
 			}
 		case fs.ModeCharDevice:
-			var dev int
-			sys := fi.Sys()
-			st1, ok1 := sys.(*syscall.Stat_t)
-			st2, ok2 := sys.(*unix.Stat_t)
-			switch {
-			case ok1:
-				dev = int(st1.Rdev)
-			case ok2:
-				dev = int(st2.Rdev)
-			default:
-				return fmt.Errorf("unsupported type %T", sys)
-			}
-			err = f.overrides.Mknod(path, uint32(unix.S_IFCHR|mode), dev)
+			return f.modeCharDevice(path, fi, mode)
 		default:
 			var memFile File
 			memFile, err = f.overrides.OpenFile(path, os.O_CREATE, perm)
@@ -492,14 +477,7 @@ func (f *dirFS) Chown(path string, uid int, gid int) error {
 }
 
 func (f *dirFS) Mknod(name string, mode uint32, dev int) error {
-	if f.caseSensitiveOnDisk(name) {
-		err := unix.Mknod(filepath.Join(f.base, name), mode, dev)
-		// what if we could not create it? Just create a regular file there, and memory will override
-		if err != nil {
-			_ = os.WriteFile(filepath.Join(f.base, name), nil, 0)
-		}
-	}
-	return f.overrides.Mknod(name, mode, dev)
+	return f.mknod(f.base, name, mode, dev)
 }
 
 // sanitize ensures that we never go beyond the root of the filesystem

pkg/apk/impl/fs/rwosfs_unix.go

@@ -0,0 +1,92 @@
+// Copyright 2022, 2023 Chainguard, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//  	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//go:build unix
+// +build unix
+
+package fs
+
+import (
+	"encoding/binary"
+	"fmt"
+	"io/fs"
+	"os"
+	"path/filepath"
+	"syscall"
+
+	"golang.org/x/sys/unix"
+)
+
+func (f *dirFS) modeCharDevice(path string, fi fs.FileInfo, mode fs.FileMode) error {
+	var dev int
+	sys := fi.Sys()
+	st1, ok1 := sys.(*syscall.Stat_t)
+	st2, ok2 := sys.(*unix.Stat_t)
+	switch {
+	case ok1:
+		dev = int(st1.Rdev)
+	case ok2:
+		dev = int(st2.Rdev)
+	default:
+		return fmt.Errorf("unsupported type %T", sys)
+	}
+	return f.overrides.Mknod(path, uint32(unix.S_IFCHR|mode), dev)
+}
+
+func (f *dirFS) mknod(base, name string, mode uint32, dev int) error {
+	if f.caseSensitiveOnDisk(name) {
+		err := unix.Mknod(filepath.Join(f.base, name), mode, dev)
+		// what if we could not create it? Just create a regular file there, and memory will override
+		if err != nil {
+			_ = os.WriteFile(filepath.Join(f.base, name), nil, 0)
+		}
+	}
+	return f.overrides.Mknod(name, mode, dev)
+}
+
+func (m *memFS) mknod(path string, mode uint32, dev int) error {
+	file, err := m.OpenFile(
+		path,
+		os.O_CREATE|os.O_WRONLY|os.O_TRUNC,
+		fs.FileMode(mode)|os.ModeCharDevice|os.ModeDevice,
+	)
+	if err != nil {
+		return err
+	}
+	defer file.Close()
+	// save the major and minor numbers in the file itself
+	devNumbers := []uint32{unix.Major(uint64(dev)), unix.Minor(uint64(dev))}
+	return binary.Write(file, binary.LittleEndian, devNumbers)
+}
+
+func (m *memFS) readnod(name string) (dev int, err error) {
+	file, err := m.Open(name)
+	if err != nil {
+		return 0, err
+	}
+	defer file.Close()
+	fi, err := file.Stat()
+	if err != nil {
+		return 0, err
+	}
+	if fi.Mode()&os.ModeCharDevice != os.ModeCharDevice {
+		return 0, fmt.Errorf("%s not a character device", name)
+	}
+	// read the major and minor numbers from the file itself
+	devNumbers := make([]uint32, 2)
+	if err := binary.Read(file, binary.LittleEndian, devNumbers); err != nil {
+		return 0, err
+	}
+	return int(unix.Mkdev(devNumbers[0], devNumbers[1])), nil
+}

pkg/apk/impl/implementation.go

@@ -31,7 +31,6 @@ import (
 	"gitlab.alpinelinux.org/alpine/go/pkg/repository"
 	"go.lsp.dev/uri"
 	"golang.org/x/sync/errgroup"
-	"golang.org/x/sys/unix"
 
 	apkfs "chainguard.dev/apko/pkg/apk/impl/fs"
 )
@@ -234,8 +233,7 @@ func (a *APKImplementation) InitDB(versions ...string) error {
 		}
 	}
 	for _, e := range initDeviceFiles {
-		perms := uint32(e.perms.Perm())
-		err := a.fs.Mknod(e.path, unix.S_IFCHR|perms, int(unix.Mkdev(e.major, e.minor)))
+		err := a.initDeviceFile(e)
 		if !a.ignoreMknodErrors && err != nil {
 			return fmt.Errorf("failed to create char device %s: %w", e.path, err)
 		}

pkg/apk/impl/implementation_unix.go

@@ -0,0 +1,25 @@
+// Copyright 2023 Chainguard, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//go:build unix
+// +build unix
+
+package impl
+
+import "golang.org/x/sys/unix"
+
+func (a *APKImplementation) initDeviceFile(e deviceFile) error {
+	perms := uint32(e.perms.Perm())
+	return a.fs.Mknod(e.path, unix.S_IFCHR|perms, int(unix.Mkdev(e.major, e.minor)))
+}

pkg/apk/impl/implementation_windows.go

@@ -0,0 +1,20 @@
+// Copyright 2023 Chainguard, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//go:build windows
+// +build windows
+
+package impl
+
+func (a *APKImplementation) initDeviceFile(e deviceFile) error { return nil }

pkg/apk/impl/installed.go

@@ -126,7 +126,7 @@ func (a *APKImplementation) updateScriptsTar(pkg *repository.Package, controlTar
 	}
 	// only need to rewind if the file has tar in it
 	if fi.Size() >= 1024 {
-		if _, err = scripts.Seek(-1024, os.SEEK_END); err != nil {
+		if _, err = scripts.Seek(-1024, io.SeekEnd); err != nil {
 			return fmt.Errorf("could not seek to end of tar file: %w", err)
 		}
 	}

pkg/build/chardevices.go → pkg/build/chardevices_unix.go

@@ -1,3 +1,20 @@
+// Copyright 2022, 2023 Chainguard, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//go:build unix
+// +build unix
+
 package build
 
 import (

pkg/build/chardevices_windows.go

@@ -0,0 +1,22 @@
+// Copyright 2022, 2023 Chainguard, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//go:build windows
+// +build windows
+
+package build
+
+import apkfs "chainguard.dev/apko/pkg/apk/impl/fs"
+
+func (*defaultBuildImplementation) InstallCharDevices(apkfs.FullFS) error { return nil }