unix: add Mremap for netbsd

Fixes golang/go#60409

Change-Id: I2d872a1a6fb63c27ab3753deff370e1c2f752bdd
Reviewed-on: https://go-review.googlesource.com/c/sys/+/508397
Auto-Submit: Tobias Klauser <[email protected]>
Run-TryBot: Tobias Klauser <[email protected]>
Reviewed-by: Benny Siegert <[email protected]>
TryBot-Result: Gopher Robot <[email protected]>
Reviewed-by: Ian Lance Taylor <[email protected]>

Author: tklauser

unix/export_mremap_test.go

@@ -0,0 +1,13 @@
+// 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
+// +build linux netbsd
+
+package unix
+
+const (
+	MremapFixed   = mremapFixed
+	MremapMaymove = mremapMaymove
+)

unix/mmap_nomremap.go

@@ -0,0 +1,14 @@
+// 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 aix || darwin || dragonfly || freebsd || openbsd || solaris
+// +build aix darwin dragonfly freebsd openbsd solaris
+
+package unix
+
+var mapper = &mmapper{
+	active: make(map[*byte][]byte),
+	mmap:   mmap,
+	munmap: munmap,
+}

unix/mremap.go

@@ -2,8 +2,8 @@
 // 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
+//go:build linux || netbsd
+// +build linux netbsd
 
 package unix
 
@@ -14,8 +14,17 @@ type mremapMmapper struct {
 	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&MREMAP_FIXED != 0 {
+	if newLength <= 0 || len(oldData) == 0 || len(oldData) != cap(oldData) || flags&mremapFixed != 0 {
 		return nil, EINVAL
 	}
 
@@ -32,9 +41,13 @@ func (m *mremapMmapper) Mremap(oldData []byte, newLength int, flags int) (data [
 	}
 	bNew := unsafe.Slice((*byte)(unsafe.Pointer(newAddr)), newLength)
 	pNew := &bNew[cap(bNew)-1]
-	if flags&MREMAP_DONTUNMAP == 0 {
+	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)
+}

unix/mremap_test.go

@@ -2,8 +2,8 @@
 // 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
+//go:build linux || netbsd
+// +build linux netbsd
 
 package unix_test
 
@@ -24,7 +24,7 @@ func TestMremap(t *testing.T) {
 
 	b[0] = 42
 
-	bNew, err := unix.Mremap(b, unix.Getpagesize()*2, unix.MREMAP_MAYMOVE)
+	bNew, err := unix.Mremap(b, unix.Getpagesize()*2, unix.MremapMaymove)
 	if err != nil {
 		t.Fatalf("Mremap2: %v", err)
 	}
@@ -40,8 +40,8 @@ func TestMremap(t *testing.T) {
 		t.Fatal("new memory cap not equal to specified len")
 	}
 
-	_, err = unix.Mremap(b, unix.Getpagesize(), unix.MREMAP_FIXED)
+	_, err = unix.Mremap(b, unix.Getpagesize(), unix.MremapFixed)
 	if err != unix.EINVAL {
-		t.Fatalf("unix.MREMAP_FIXED should be forbidden")
+		t.Fatalf("remapping to a fixed address; got %v, want %v", err, unix.EINVAL)
 	}
 }

unix/syscall_aix.go

@@ -535,21 +535,6 @@ func Fsync(fd int) error {
 //sys	sendmsg(s int, msg *Msghdr, flags int) (n int, err error) = nsendmsg
 
 //sys	munmap(addr uintptr, length uintptr) (err error)
-
-var mapper = &mmapper{
-	active: make(map[*byte][]byte),
-	mmap:   mmap,
-	munmap: munmap,
-}
-
-func Mmap(fd int, offset int64, length int, prot int, flags int) (data []byte, err error) {
-	return mapper.Mmap(fd, offset, length, prot, flags)
-}
-
-func Munmap(b []byte) (err error) {
-	return mapper.Munmap(b)
-}
-
 //sys	Madvise(b []byte, advice int) (err error)
 //sys	Mprotect(b []byte, prot int) (err error)
 //sys	Mlock(b []byte) (err error)

unix/syscall_bsd.go

@@ -601,20 +601,6 @@ func Poll(fds []PollFd, timeout int) (n int, err error) {
 //	Gethostuuid(uuid *byte, timeout *Timespec) (err error)
 //	Ptrace(req int, pid int, addr uintptr, data int) (ret uintptr, err error)
 
-var mapper = &mmapper{
-	active: make(map[*byte][]byte),
-	mmap:   mmap,
-	munmap: munmap,
-}
-
-func Mmap(fd int, offset int64, length int, prot int, flags int) (data []byte, err error) {
-	return mapper.Mmap(fd, offset, length, prot, flags)
-}
-
-func Munmap(b []byte) (err error) {
-	return mapper.Munmap(b)
-}
-
 //sys	Madvise(b []byte, behav int) (err error)
 //sys	Mlock(b []byte) (err error)
 //sys	Mlockall(flags int) (err error)

unix/syscall_linux.go

@@ -2125,28 +2125,6 @@ func writevRacedetect(iovecs []Iovec, n int) {
 // mmap varies by architecture; see syscall_linux_*.go.
 //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 = &mremapMmapper{
-	mmapper: mmapper{
-		active: make(map[*byte][]byte),
-		mmap:   mmap,
-		munmap: munmap,
-	},
-	mremap: mremap,
-}
-
-func Mmap(fd int, offset int64, length int, prot int, flags int) (data []byte, err error) {
-	return mapper.Mmap(fd, offset, length, prot, flags)
-}
-
-func Munmap(b []byte) (err error) {
-	return mapper.Munmap(b)
-}
-
-func Mremap(oldData []byte, newLength int, flags int) (data []byte, err error) {
-	return mapper.Mremap(oldData, newLength, flags)
-}
-
 //sys	Madvise(b []byte, advice int) (err error)
 //sys	Mprotect(b []byte, prot int) (err error)
 //sys	Mlock(b []byte) (err error)
@@ -2155,6 +2133,12 @@ func Mremap(oldData []byte, newLength int, flags int) (data []byte, err error) {
 //sys	Munlock(b []byte) (err error)
 //sys	Munlockall() (err error)
 
+const (
+	mremapFixed     = MREMAP_FIXED
+	mremapDontunmap = MREMAP_DONTUNMAP
+	mremapMaymove   = MREMAP_MAYMOVE
+)
+
 // Vmsplice splices user pages from a slice of Iovecs into a pipe specified by fd,
 // using the specified flags.
 func Vmsplice(fd int, iovs []Iovec, flags int) (int, error) {

unix/syscall_netbsd.go

@@ -360,6 +360,18 @@ func Statvfs(path string, buf *Statvfs_t) (err error) {
 //sys	writelen(fd int, buf *byte, nbuf int) (n int, err error) = SYS_WRITE
 //sys	utimensat(dirfd int, path string, times *[2]Timespec, flags int) (err error)
 
+const (
+	mremapFixed     = MAP_FIXED
+	mremapDontunmap = 0
+	mremapMaymove   = 0
+)
+
+//sys	mremapNetBSD(oldp uintptr, oldsize uintptr, newp uintptr, newsize uintptr, flags int) (xaddr uintptr, err error) = SYS_MREMAP
+
+func mremap(oldaddr uintptr, oldlength uintptr, newlength uintptr, flags int, newaddr uintptr) (uintptr, error) {
+	return mremapNetBSD(oldaddr, oldlength, newaddr, newlength, flags)
+}
+
 /*
  * Unimplemented
  */
@@ -564,7 +576,6 @@ func Statvfs(path string, buf *Statvfs_t) (err error) {
 // mq_timedreceive
 // mq_timedsend
 // mq_unlink
-// mremap
 // msgget
 // msgrcv
 // msgsnd

unix/syscall_solaris.go

@@ -716,20 +716,6 @@ func writelen(fd int, buf *byte, nbuf int) (n int, err error) {
 	return
 }
 
-var mapper = &mmapper{
-	active: make(map[*byte][]byte),
-	mmap:   mmap,
-	munmap: munmap,
-}
-
-func Mmap(fd int, offset int64, length int, prot int, flags int) (data []byte, err error) {
-	return mapper.Mmap(fd, offset, length, prot, flags)
-}
-
-func Munmap(b []byte) (err error) {
-	return mapper.Munmap(b)
-}
-
 // Event Ports
 
 type fileObjCookie struct {

unix/syscall_unix.go

@@ -147,6 +147,14 @@ func (m *mmapper) Munmap(data []byte) (err error) {
 	return nil
 }
 
+func Mmap(fd int, offset int64, length int, prot int, flags int) (data []byte, err error) {
+	return mapper.Mmap(fd, offset, length, prot, flags)
+}
+
+func Munmap(b []byte) (err error) {
+	return mapper.Munmap(b)
+}
+
 func Read(fd int, p []byte) (n int, err error) {
 	n, err = read(fd, p)
 	if raceenabled {

unix/syscall_zos_s390x.go

@@ -285,25 +285,11 @@ func Close(fd int) (err error) {
 	return
 }
 
-var mapper = &mmapper{
-	active: make(map[*byte][]byte),
-	mmap:   mmap,
-	munmap: munmap,
-}
-
 // Dummy function: there are no semantics for Madvise on z/OS
 func Madvise(b []byte, advice int) (err error) {
 	return
 }
 
-func Mmap(fd int, offset int64, length int, prot int, flags int) (data []byte, err error) {
-	return mapper.Mmap(fd, offset, length, prot, flags)
-}
-
-func Munmap(b []byte) (err error) {
-	return mapper.Munmap(b)
-}
-
 //sys   Gethostname(buf []byte) (err error) = SYS___GETHOSTNAME_A
 //sysnb	Getegid() (egid int)
 //sysnb	Geteuid() (uid int)