From 792c48e5130bf33d14a6a7fdfbe437439a4a93d2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Anders=20F=20Bj=C3=B6rklund?= <anders.f.bjorklund@gmail.com>
Date: Sun, 19 Jun 2022 13:07:03 +0200
Subject: [PATCH] Add windows version of lockutil from nerdctl
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Also include netbsd, next to freebsd + linux

Signed-off-by: Anders F Björklund <anders.f.bjorklund@gmail.com>
---
 .../{lockutil.go => lockutil_unix.go}         |  5 +-
 pkg/lockutil/lockutil_windows.go              | 70 +++++++++++++++++++
 2 files changed, 74 insertions(+), 1 deletion(-)
 rename pkg/lockutil/{lockutil.go => lockutil_unix.go} (90%)
 create mode 100644 pkg/lockutil/lockutil_windows.go

diff --git a/pkg/lockutil/lockutil.go b/pkg/lockutil/lockutil_unix.go
similarity index 90%
rename from pkg/lockutil/lockutil.go
rename to pkg/lockutil/lockutil_unix.go
index cafe58eca7fc..f5abb778c3e6 100644
--- a/pkg/lockutil/lockutil.go
+++ b/pkg/lockutil/lockutil_unix.go
@@ -1,4 +1,7 @@
-// From https://github.com/containerd/nerdctl/blob/v0.9.0/pkg/lockutil/lockutil_linux.go
+//go:build !windows
+// +build !windows
+
+// From https://github.com/containerd/nerdctl/blob/v0.13.0/pkg/lockutil/lockutil_unix.go
 /*
    Copyright The containerd Authors.
 
diff --git a/pkg/lockutil/lockutil_windows.go b/pkg/lockutil/lockutil_windows.go
new file mode 100644
index 000000000000..9ac2394d629c
--- /dev/null
+++ b/pkg/lockutil/lockutil_windows.go
@@ -0,0 +1,70 @@
+// From https://github.com/containerd/nerdctl/blob/v0.13.0/pkg/lockutil/lockutil_windows.go
+/*
+   Copyright The containerd Authors.
+
+   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.
+*/
+
+package lockutil
+
+import (
+	"fmt"
+	"os"
+	"syscall"
+	"unsafe"
+
+	"github.com/sirupsen/logrus"
+)
+
+// LockFile modified from https://github.com/boltdb/bolt/blob/v1.3.1/bolt_windows.go using MIT
+var (
+	modkernel32      = syscall.NewLazyDLL("kernel32.dll")
+	procLockFileEx   = modkernel32.NewProc("LockFileEx")
+	procUnlockFileEx = modkernel32.NewProc("UnlockFileEx")
+)
+
+func WithDirLock(dir string, fn func() error) error {
+	dirFile, err := os.OpenFile(dir+".lock", os.O_CREATE, 0644)
+	if err != nil {
+		return err
+	}
+	defer dirFile.Close()
+	// see https://msdn.microsoft.com/en-us/library/windows/desktop/aa365203(v=vs.85).aspx
+	// 1 lock immediately
+	if err := lockFileEx(syscall.Handle(dirFile.Fd()), 1, 0, 1, 0, &syscall.Overlapped{}); err != nil {
+		return fmt.Errorf("failed to lock %q: %w", dir, err)
+	}
+
+	defer func() {
+		if err := unlockFileEx(syscall.Handle(dirFile.Fd()), 0, 1, 0, &syscall.Overlapped{}); err != nil {
+			logrus.WithError(err).Errorf("failed to unlock %q", dir)
+		}
+	}()
+	return fn()
+}
+
+func lockFileEx(h syscall.Handle, flags, reserved, locklow, lockhigh uint32, ol *syscall.Overlapped) (err error) {
+	r, _, err := procLockFileEx.Call(uintptr(h), uintptr(flags), uintptr(reserved), uintptr(locklow), uintptr(lockhigh), uintptr(unsafe.Pointer(ol)))
+	if r == 0 {
+		return err
+	}
+	return nil
+}
+
+func unlockFileEx(h syscall.Handle, reserved, locklow, lockhigh uint32, ol *syscall.Overlapped) (err error) {
+	r, _, err := procUnlockFileEx.Call(uintptr(h), uintptr(reserved), uintptr(locklow), uintptr(lockhigh), uintptr(unsafe.Pointer(ol)), 0)
+	if r == 0 {
+		return err
+	}
+	return nil
+}