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unix: add Mremap for linux

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For golang/go#60409

Change-Id: I75a9732ee996f0aeb91599d80803f96ada468c27
GitHub-Last-Rev: c348b6194d9fbe92f4f912c66709b0af75810e99
GitHub-Pull-Request: golang/sys#164
Reviewed-on: https://go-review.googlesource.com/c/sys/+/502715
Auto-Submit: Ian Lance Taylor <iant@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Bryan Mills <bcmills@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Run-TryBot: Ian Lance Taylor <iant@google.com>
This commit is contained in:
Anton Kuklin
2023-06-16 19:37:35 +00:00
committed by Gopher Robot
parent ca096e46e8
commit e0c3b6e6ae
6 changed files with 114 additions and 6 deletions
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unix/mkerrors.sh
+1 -1
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@@ -519,7 +519,7 @@ ccflags="$@"
$2 ~ /^LOCK_(SH|EX|NB|UN)$/ ||
$2 ~ /^LO_(KEY|NAME)_SIZE$/ ||
$2 ~ /^LOOP_(CLR|CTL|GET|SET)_/ ||
$2 ~ /^(AF|SOCK|SO|SOL|IPPROTO|IP|IPV6|TCP|MCAST|EVFILT|NOTE|SHUT|PROT|MAP|MFD|T?PACKET|MSG|SCM|MCL|DT|MADV|PR|LOCAL|TCPOPT|UDP)_/ ||
$2 ~ /^(AF|SOCK|SO|SOL|IPPROTO|IP|IPV6|TCP|MCAST|EVFILT|NOTE|SHUT|PROT|MAP|MREMAP|MFD|T?PACKET|MSG|SCM|MCL|DT|MADV|PR|LOCAL|TCPOPT|UDP)_/ ||
$2 ~ /^NFC_(GENL|PROTO|COMM|RF|SE|DIRECTION|LLCP|SOCKPROTO)_/ ||
$2 ~ /^NFC_.*_(MAX)?SIZE$/ ||
$2 ~ /^RAW_PAYLOAD_/ ||
unix/mremap.go
+40
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@@ -0,0 +1,40 @@
// 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
// +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) || flags&MREMAP_FIXED != 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&MREMAP_DONTUNMAP == 0 {
delete(m.active, pOld)
}
m.active[pNew] = bNew
return bNew, nil
}
unix/mremap_test.go
+47
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@@ -0,0 +1,47 @@
// 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
// +build linux
package unix_test
import (
"testing"
"golang.org/x/sys/unix"
)
func TestMremap(t *testing.T) {
b, err := unix.Mmap(-1, 0, unix.Getpagesize(), unix.PROT_NONE, unix.MAP_ANON|unix.MAP_PRIVATE)
if err != nil {
t.Fatalf("Mmap: %v", err)
}
if err := unix.Mprotect(b, unix.PROT_READ|unix.PROT_WRITE); err != nil {
t.Fatalf("Mprotect: %v", err)
}
b[0] = 42
bNew, err := unix.Mremap(b, unix.Getpagesize()*2, unix.MREMAP_MAYMOVE)
if err != nil {
t.Fatalf("Mremap2: %v", err)
}
bNew[unix.Getpagesize()+1] = 84 // checks
if bNew[0] != 42 {
t.Fatal("first element value was changed")
}
if len(bNew) != unix.Getpagesize()*2 {
t.Fatal("new memory len not equal to specified len")
}
if cap(bNew) != unix.Getpagesize()*2 {
t.Fatal("new memory cap not equal to specified len")
}
_, err = unix.Mremap(b, unix.Getpagesize(), unix.MREMAP_FIXED)
if err != unix.EINVAL {
t.Fatalf("unix.MREMAP_FIXED should be forbidden")
}
}
unix/syscall_linux.go
+12 -5
View File
@@ -2124,11 +2124,15 @@ 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 = &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,
}
func Mmap(fd int, offset int64, length int, prot int, flags int) (data []byte, err error) {
@@ -2139,6 +2143,10 @@ 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)
@@ -2487,7 +2495,6 @@ func Getresgid() (rgid, egid, sgid int) {
// MqTimedreceive
// MqTimedsend
// MqUnlink
// Mremap
// Msgctl
// Msgget
// Msgrcv
unix/zerrors_linux.go
+3
View File
@@ -1904,6 +1904,9 @@ const (
MOUNT_ATTR_SIZE_VER0 = 0x20
MOUNT_ATTR_STRICTATIME = 0x20
MOUNT_ATTR__ATIME = 0x70
MREMAP_DONTUNMAP = 0x4
MREMAP_FIXED = 0x2
MREMAP_MAYMOVE = 0x1
MSDOS_SUPER_MAGIC = 0x4d44
MSG_BATCH = 0x40000
MSG_CMSG_CLOEXEC = 0x40000000
unix/zsyscall_linux.go
+11
View File
@@ -1868,6 +1868,17 @@ func munmap(addr uintptr, length uintptr) (err error) {
// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
func mremap(oldaddr uintptr, oldlength uintptr, newlength uintptr, flags int, newaddr uintptr) (xaddr uintptr, err error) {
r0, _, e1 := Syscall6(SYS_MREMAP, uintptr(oldaddr), uintptr(oldlength), uintptr(newlength), uintptr(flags), uintptr(newaddr), 0)
xaddr = uintptr(r0)
if e1 != 0 {
err = errnoErr(e1)
}
return
}
// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
func Madvise(b []byte, advice int) (err error) {
var _p0 unsafe.Pointer
if len(b) > 0 {