Create a correctly-sized slice to proxy *uint16

appveyor.yml

@@ -1,14 +1,14 @@
 version: 0.1.{build}
 
-image: Visual Studio 2017
+image: Visual Studio 2019
 
 clone_folder: c:\gopath\src\github.com\Microsoft\hcsshim
 
 environment:
   GOPATH: c:\gopath
   PATH: "%GOPATH%\\bin;C:\\gometalinter-2.0.12-windows-amd64;%PATH%"
 
-stack: go 1.13.4
+stack: go 1.15
 
 build_script:
   - appveyor DownloadFile https://github.com/alecthomas/gometalinter/releases/download/v2.0.12/gometalinter-2.0.12-windows-amd64.zip
@@ -19,16 +19,16 @@ build_script:
   - go build ./cmd/tar2ext4
   - go build ./cmd/wclayer
   - go build ./cmd/device-util
-  - go build ./internal/tools/grantvmgroupaccess 
+  - go build ./internal/tools/grantvmgroupaccess
   - go build ./internal/tools/uvmboot
   - go build ./internal/tools/zapdir
-  - go test -v ./... -tags admin
+  - go test -gcflags=all=-d=checkptr -v ./... -tags admin
   - cd test
-  - go test -v ./internal -tags admin
-  - go test -c ./containerd-shim-runhcs-v1/ -tags functional
-  - go test -c ./cri-containerd/ -tags functional
-  - go test -c ./functional/ -tags functional
-  - go test -c ./runhcs/ -tags functional
+  - go test -gcflags=all=-d=checkptr -v ./internal -tags admin
+  - go test -gcflags=all=-d=checkptr -c ./containerd-shim-runhcs-v1/ -tags functional
+  - go test -gcflags=all=-d=checkptr -c ./cri-containerd/ -tags functional
+  - go test -gcflags=all=-d=checkptr -c ./functional/ -tags functional
+  - go test -gcflags=all=-d=checkptr -c ./runhcs/ -tags functional
   - go build -o sample-logging-driver.exe ./cri-containerd/helpers/log.go
 
 artifacts:

internal/safefile/safeopen.go

@@ -177,7 +177,7 @@ func LinkRelative(oldname string, oldroot *os.File, newname string, newroot *os.
 	linkinfo := (*winapi.FileLinkInformation)(unsafe.Pointer(linkinfoBuffer))
 	linkinfo.RootDirectory = parent.Fd()
 	linkinfo.FileNameLength = uint32(len(newbase16) * 2)
-	copy((*[32768]uint16)(unsafe.Pointer(&linkinfo.FileName[0]))[:], newbase16)
+	copy(winapi.Uint16BufferToSlice(&linkinfo.FileName[0], len(newbase16)), newbase16)
 
 	var iosb winapi.IOStatusBlock
 	status := winapi.NtSetInformationFile(

internal/winapi/utils.go

@@ -2,12 +2,24 @@ package winapi
 
 import (
 	"errors"
+	"reflect"
 	"syscall"
 	"unsafe"
 
 	"golang.org/x/sys/windows"
 )
 
+// Uint16BufferToSlice wraps a uint16 pointer-and-length into a slice
+// for easier interop with Go APIs
+func Uint16BufferToSlice(buffer *uint16, bufferLength int) (result []uint16) {
+	hdr := (*reflect.SliceHeader)(unsafe.Pointer(&result))
+	hdr.Data = uintptr(unsafe.Pointer(buffer))
+	hdr.Cap = bufferLength
+	hdr.Len = bufferLength
+
+	return
+}
+
 type UnicodeString struct {
 	Length        uint16
 	MaximumLength uint16
@@ -16,12 +28,9 @@ type UnicodeString struct {
 
 //String converts a UnicodeString to a golang string
 func (uni UnicodeString) String() string {
-	p := (*[0xffff]uint16)(unsafe.Pointer(uni.Buffer))
-
 	// UnicodeString is not guaranteed to be null terminated, therefore
 	// use the UnicodeString's Length field
-	lengthInChars := uni.Length / 2
-	return syscall.UTF16ToString(p[:lengthInChars])
+	return syscall.UTF16ToString(Uint16BufferToSlice(uni.Buffer, int(uni.Length/2)))
 }
 
 // NewUnicodeString allocates a new UnicodeString and copies `s` into

internal/winapi/winapi_test.go

@@ -3,12 +3,10 @@ package winapi
 import (
 	"testing"
 	"unicode/utf16"
-	"unsafe"
 )
 
-func wideStringsEqual(target, actual []uint16, actualLengthInBytes int) bool {
-	actualLength := actualLengthInBytes / 2
-	if len(target) != actualLength {
+func wideStringsEqual(target, actual []uint16) bool {
+	if len(target) != len(actual) {
 		return false
 	}
 
@@ -38,13 +36,10 @@ func TestNewUnicodeString(t *testing.T) {
 			t.Fatalf("Expected new Unicode String maximum length to be %d for target string %s, got %d instead", targetLength, target, uni.MaximumLength)
 		}
 
-		uniBufferStringAsSlice := (*[32768]uint16)(unsafe.Pointer(uni.Buffer))[:]
+		uniBufferStringAsSlice := Uint16BufferToSlice(uni.Buffer, len(target))
 
-		// since we have to do casting to convert the unicode string's buffer into a uint16 slice
-		// the length of the actual slice will not be the true length of the contents in the unicode buffer
-		// therefore we need to use the unicode string's length field when comparing
-		if !wideStringsEqual(targetWideString, uniBufferStringAsSlice, int(uni.Length)) {
-			t.Fatalf("Expected wide string %v, got %v instead", targetWideString, uniBufferStringAsSlice[:uni.Length])
+		if !wideStringsEqual(targetWideString, uniBufferStringAsSlice) {
+			t.Fatalf("Expected wide string %v, got %v instead", targetWideString, uniBufferStringAsSlice)
 		}
 	}
 }