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