unix: add Sysv shared memory support

Implements proposed API from https://golang.org/issue/46084. I chose `SysvShmDesc` since it's a clearer name than `SysvShm`. Initially supports Darwin and Linux. Solaris support has a blocker (https://golang.org/issue/46084#issuecomment-836980018) For golang/go#46084 Change-Id: Ied0f768a74c448254adc3315348417825a7ec63e GitHub-Last-Rev: befbd7af6b2f838753ac163ef387cebdb7957467 GitHub-Pull-Request: golang/sys#110 Reviewed-on: https://go-review.googlesource.com/c/sys/+/327830 Reviewed-by: Tobias Klauser <tobias.klauser@gmail.com> Reviewed-by: Ian Lance Taylor <iant@golang.org> Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com> TryBot-Result: Go Bot <gobot@golang.org>
2026-09-05 08:37:31 -04:00 · 2021-09-30 14:19:18 +00:00
parent 39ccf1dd6f
commit 969570ce7c
29 changed files with 841 additions and 8 deletions
@@ -0,0 +1,74 @@
+// Copyright 2021 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 (darwin && amd64) || linux
+// +build darwin,amd64 linux
+
+package unix_test
+
+import (
+	"runtime"
+	"testing"
+
+	"golang.org/x/sys/unix"
+)
+
+func TestSysvSharedMemory(t *testing.T) {
+	// create ipc
+	id, err := unix.SysvShmGet(unix.IPC_PRIVATE, 1024, unix.IPC_CREAT|unix.IPC_EXCL|0o600)
+
+	// ipc isn't implemented on android, should fail
+	if runtime.GOOS == "android" {
+		if err != unix.ENOSYS {
+			t.Fatalf("expected android to fail, but it didn't")
+		}
+		return
+	}
+
+	if err != nil {
+		t.Fatalf("SysvShmGet: %v", err)
+	}
+	defer func() {
+		_, err := unix.SysvShmCtl(id, unix.IPC_RMID, nil)
+		if err != nil {
+			t.Errorf("Remove failed: %v", err)
+		}
+	}()
+
+	// attach
+	b1, err := unix.SysvShmAttach(id, 0, 0)
+	if err != nil {
+		t.Fatalf("Attach: %v", err)
+	}
+
+	if len(b1) != 1024 {
+		t.Fatalf("b1 len = %v, want 1024", len(b1))
+	}
+
+	b1[42] = 'x'
+
+	// attach again
+	b2, err := unix.SysvShmAttach(id, 0, 0)
+	if err != nil {
+		t.Fatalf("Attach: %v", err)
+	}
+
+	if len(b2) != 1024 {
+		t.Fatalf("b2 len = %v, want 1024", len(b1))
+	}
+
+	b2[43] = 'y'
+	if b2[42] != 'x' || b1[43] != 'y' {
+		t.Fatalf("shared memory isn't shared")
+	}
+
+	// detach
+	if err = unix.SysvShmDetach(b2); err != nil {
+		t.Fatalf("Detach: %v", err)
+	}
+
+	if b1[42] != 'x' || b1[43] != 'y' {
+		t.Fatalf("shared memory was invalidated")
+	}
+}