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-rw-r--r--pkg/sentry/arch/aligned.go31
1 files changed, 31 insertions, 0 deletions
diff --git a/pkg/sentry/arch/aligned.go b/pkg/sentry/arch/aligned.go
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+++ b/pkg/sentry/arch/aligned.go
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+// Copyright 2018 The gVisor 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 arch
+
+import (
+ "reflect"
+)
+
+// alignedBytes returns a slice of size bytes, aligned in memory to the given
+// alignment. This is used because we require certain structures to be aligned
+// in a specific way (for example, the X86 floating point data).
+func alignedBytes(size, alignment uint) []byte {
+ data := make([]byte, size+alignment-1)
+ offset := uint(reflect.ValueOf(data).Index(0).Addr().Pointer() % uintptr(alignment))
+ if offset == 0 {
+ return data[:size:size]
+ }
+ return data[alignment-offset:][:size:size]
+}