unix: add unsafe mmap, munmap, mremap
Fixes golang/go#56123
Change-Id: I63a7a6fb3a5b1bb556ac19d76a1e0b04a03ebcfa
GitHub-Last-Rev: 39dbc8e308807bd07863b6f5a49bcdcf506bc0e7
GitHub-Pull-Request: golang/sys#197
Reviewed-on: https://go-review.googlesource.com/c/sys/+/592415
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Dmitri Shuralyov <dmitshur@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
diff --git a/unix/mmap_unix_test.go b/unix/mmap_unix_test.go
index a60a0f6..eb14605 100644
--- a/unix/mmap_unix_test.go
+++ b/unix/mmap_unix_test.go
@@ -9,6 +9,7 @@
import (
"runtime"
"testing"
+ "unsafe"
"golang.org/x/sys/unix"
)
@@ -49,3 +50,25 @@
t.Fatalf("Munmap: %v", err)
}
}
+
+func TestMmapPtr(t *testing.T) {
+ mmapProt := unix.PROT_NONE
+ mmapPtrProt := unix.PROT_READ | unix.PROT_WRITE
+ b, err := unix.Mmap(-1, 0, 2*unix.Getpagesize(), mmapProt, unix.MAP_ANON|unix.MAP_PRIVATE)
+ if err != nil {
+ t.Fatalf("Mmap: %v", err)
+ }
+ if _, err := unix.MmapPtr(-1, 0, unsafe.Pointer(&b[0]), uintptr(unix.Getpagesize()),
+ mmapPtrProt, unix.MAP_ANON|unix.MAP_PRIVATE|unix.MAP_FIXED); err != nil {
+ t.Fatalf("MmapPtr: %v", err)
+ }
+
+ b[0] = 42
+
+ if err := unix.MunmapPtr(unsafe.Pointer(&b[0]), uintptr(unix.Getpagesize())); err != nil {
+ t.Fatalf("MunmapPtr: %v", err)
+ }
+ if err := unix.Munmap(b); err != nil {
+ t.Fatalf("Munmap: %v", err)
+ }
+}
diff --git a/unix/mremap.go b/unix/mremap.go
index fd45fe5..3a5e776 100644
--- a/unix/mremap.go
+++ b/unix/mremap.go
@@ -50,3 +50,8 @@
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
+}
diff --git a/unix/mremap_test.go b/unix/mremap_test.go
index e84104f..5019dd7 100644
--- a/unix/mremap_test.go
+++ b/unix/mremap_test.go
@@ -8,6 +8,7 @@
import (
"testing"
+ "unsafe"
"golang.org/x/sys/unix"
)
@@ -44,3 +45,32 @@
t.Fatalf("remapping to a fixed address; got %v, want %v", err, unix.EINVAL)
}
}
+
+func TestMremapPtr(t *testing.T) {
+ mmapProt := unix.PROT_NONE
+ mmapPtrProt := unix.PROT_READ | unix.PROT_WRITE
+ b, err := unix.Mmap(-1, 0, 2*unix.Getpagesize(), mmapProt, unix.MAP_ANON|unix.MAP_PRIVATE)
+ if err != nil {
+ t.Fatalf("Mmap: %v", err)
+ }
+ if _, err := unix.MmapPtr(-1, 0, unsafe.Pointer(&b[0]), uintptr(unix.Getpagesize()),
+ mmapPtrProt, unix.MAP_ANON|unix.MAP_PRIVATE|unix.MAP_FIXED); err != nil {
+ t.Fatalf("MmapPtr: %v", err)
+ }
+
+ b[0] = 42
+
+ if _, err := unix.MremapPtr(
+ unsafe.Pointer(&b[0]), uintptr(unix.Getpagesize()),
+ unsafe.Pointer(&b[unix.Getpagesize()]), uintptr(unix.Getpagesize()),
+ unix.MremapFixed|unix.MremapMaymove); err != nil {
+ t.Fatalf("MremapPtr: %v", err)
+ }
+ if got := b[unix.Getpagesize()]; got != 42 {
+ t.Errorf("got %d, want 42", got)
+ }
+
+ if err := unix.Munmap(b); err != nil {
+ t.Fatalf("Munmap: %v", err)
+ }
+}
diff --git a/unix/syscall_unix.go b/unix/syscall_unix.go
index 77081de..4e92e5a 100644
--- a/unix/syscall_unix.go
+++ b/unix/syscall_unix.go
@@ -154,6 +154,15 @@
return mapper.Munmap(b)
}
+func MmapPtr(fd int, offset int64, addr unsafe.Pointer, length uintptr, prot int, flags int) (ret unsafe.Pointer, err error) {
+ xaddr, err := mapper.mmap(uintptr(addr), length, prot, flags, fd, offset)
+ return unsafe.Pointer(xaddr), err
+}
+
+func MunmapPtr(addr unsafe.Pointer, length uintptr) (err error) {
+ return mapper.munmap(uintptr(addr), length)
+}
+
func Read(fd int, p []byte) (n int, err error) {
n, err = read(fd, p)
if raceenabled {
