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58 lines
1.6 KiB
58 lines
1.6 KiB
4 months ago
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// Copyright 2023 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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//go:build linux || netbsd
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package unix
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import "unsafe"
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type mremapMmapper struct {
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mmapper
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mremap func(oldaddr uintptr, oldlength uintptr, newlength uintptr, flags int, newaddr uintptr) (xaddr uintptr, err error)
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}
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var mapper = &mremapMmapper{
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mmapper: mmapper{
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active: make(map[*byte][]byte),
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mmap: mmap,
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munmap: munmap,
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},
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mremap: mremap,
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}
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func (m *mremapMmapper) Mremap(oldData []byte, newLength int, flags int) (data []byte, err error) {
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if newLength <= 0 || len(oldData) == 0 || len(oldData) != cap(oldData) || flags&mremapFixed != 0 {
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return nil, EINVAL
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}
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pOld := &oldData[cap(oldData)-1]
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m.Lock()
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defer m.Unlock()
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bOld := m.active[pOld]
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if bOld == nil || &bOld[0] != &oldData[0] {
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return nil, EINVAL
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}
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newAddr, errno := m.mremap(uintptr(unsafe.Pointer(&bOld[0])), uintptr(len(bOld)), uintptr(newLength), flags, 0)
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if errno != nil {
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return nil, errno
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}
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bNew := unsafe.Slice((*byte)(unsafe.Pointer(newAddr)), newLength)
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pNew := &bNew[cap(bNew)-1]
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if flags&mremapDontunmap == 0 {
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delete(m.active, pOld)
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}
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m.active[pNew] = bNew
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return bNew, nil
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}
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func Mremap(oldData []byte, newLength int, flags int) (data []byte, err error) {
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return mapper.Mremap(oldData, newLength, flags)
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}
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func MremapPtr(oldAddr unsafe.Pointer, oldSize uintptr, newAddr unsafe.Pointer, newSize uintptr, flags int) (ret unsafe.Pointer, err error) {
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xaddr, err := mapper.mremap(uintptr(oldAddr), oldSize, newSize, flags, uintptr(newAddr))
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return unsafe.Pointer(xaddr), err
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}
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