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57 lines
1.6 KiB
57 lines
1.6 KiB
// 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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