55 lines
1.8 KiB
Go
55 lines
1.8 KiB
Go
// Copyright 2020 The gVisor Authors.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package arch
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import (
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"unsafe"
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"gvisor.dev/gvisor/pkg/hostarch"
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"gvisor.dev/gvisor/pkg/marshal/primitive"
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)
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// pushAddrSliceAndTerminator copies a slices of addresses to the stack, and
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// also pushes an extra null address element at the end of the slice.
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//
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// Internally, we unsafely transmute the slice type from the arch-dependent
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// []hostarch.Addr type, to a slice of fixed-sized ints so that we can pass it to
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// go-marshal.
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//
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// On error, the contents of the stack and the bottom cursor are undefined.
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func (s *Stack) pushAddrSliceAndTerminator(src []hostarch.Addr) (int, error) {
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// Note: Stack grows upwards, so push the terminator first.
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switch s.Arch.Width() {
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case 8:
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nNull, err := primitive.CopyUint64Out(s, StackBottomMagic, 0)
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if err != nil {
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return 0, err
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}
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srcAsUint64 := *(*[]uint64)(unsafe.Pointer(&src))
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n, err := primitive.CopyUint64SliceOut(s, StackBottomMagic, srcAsUint64)
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return n + nNull, err
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case 4:
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nNull, err := primitive.CopyUint32Out(s, StackBottomMagic, 0)
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if err != nil {
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return 0, err
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}
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srcAsUint32 := *(*[]uint32)(unsafe.Pointer(&src))
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n, err := primitive.CopyUint32SliceOut(s, StackBottomMagic, srcAsUint32)
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return n + nNull, err
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default:
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panic("Unsupported arch width")
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}
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}
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