moved mremap mapper to a separate file

Author: anton-kuklin

unix/mremap.go

@@ -0,0 +1,40 @@
+// Copyright 2009 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
+// +build linux
+
+package unix
+
+import "unsafe"
+
+type mremapMmapper struct {
+	mmapper
+	mremap func(oldaddr uintptr, oldlength uintptr, newlength uintptr, flags int, newaddr uintptr) (xaddr uintptr, err error)
+}
+
+func (m *mremapMmapper) Mremap(oldData []byte, newLength int, flags int) (data []byte, err error) {
+	if newLength <= 0 || len(oldData) == 0 || len(oldData) != cap(oldData) {
+		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]
+	m.active[pNew] = bNew
+	if flags&MREMAP_DONTUNMAP == 0 {
+		delete(m.active, pOld)
+	}
+	return bNew, nil
+}

unix/syscall_linux.go

@@ -2126,10 +2126,12 @@ func writevRacedetect(iovecs []Iovec, n int) {
 //sys	munmap(addr uintptr, length uintptr) (err error)
 //sys	mremap(oldaddr uintptr, oldlength uintptr, newlength uintptr, flags int, newaddr uintptr) (xaddr uintptr, err error)
 
-var mapper = &mmapper{
-	active: make(map[*byte][]byte),
-	mmap:   mmap,
-	munmap: munmap,
+var mapper = &mremapMmapper{
+	mmapper: mmapper{
+		active: make(map[*byte][]byte),
+		mmap:   mmap,
+		munmap: munmap,
+	},
 	mremap: mremap,
 }
 

unix/syscall_unix.go

@@ -101,7 +101,6 @@ type mmapper struct {
 	active map[*byte][]byte // active mappings; key is last byte in mapping
 	mmap   func(addr, length uintptr, prot, flags, fd int, offset int64) (uintptr, error)
 	munmap func(addr uintptr, length uintptr) error
-	mremap func(oldaddr uintptr, oldlength uintptr, newlength uintptr, flags int, newaddr uintptr) (xaddr uintptr, err error)
 }
 
 func (m *mmapper) Mmap(fd int, offset int64, length int, prot int, flags int) (data []byte, err error) {
@@ -148,31 +147,6 @@ func (m *mmapper) Munmap(data []byte) (err error) {
 	return nil
 }
 
-func (m *mmapper) Mremap(oldData []byte, newLength int, flags int) (data []byte, err error) {
-	if newLength <= 0 || len(oldData) == 0 || len(oldData) != cap(oldData) {
-		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]
-	m.active[pNew] = bNew
-	if flags&MREMAP_DONTUNMAP == 0 {
-		delete(m.active, pOld)
-	}
-	return bNew, nil
-}
-
 func Read(fd int, p []byte) (n int, err error) {
 	n, err = read(fd, p)
 	if raceenabled {