unix: add Auxv
Fixes golang/go#67839
Change-Id: I3af38d21159f7cac3786b49ac17657d314fbc178
Reviewed-on: https://go-review.googlesource.com/c/sys/+/644295
Reviewed-by: Tobias Klauser <tobias.klauser@gmail.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Carlos Amedee <carlos@golang.org>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
diff --git a/unix/auxv.go b/unix/auxv.go
new file mode 100644
index 0000000..37a8252
--- /dev/null
+++ b/unix/auxv.go
@@ -0,0 +1,36 @@
+// Copyright 2025 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 go1.21 && (aix || darwin || dragonfly || freebsd || linux || netbsd || openbsd || solaris || zos)
+
+package unix
+
+import (
+ "syscall"
+ "unsafe"
+)
+
+//go:linkname runtime_getAuxv runtime.getAuxv
+func runtime_getAuxv() []uintptr
+
+// Auxv returns the ELF auxiliary vector as a sequence of key/value pairs.
+// The returned slice is always a fresh copy, owned by the caller.
+// It returns an error on non-ELF platforms, or if the auxiliary vector cannot be accessed,
+// which happens in some locked-down environments and build modes.
+func Auxv() ([][2]uintptr, error) {
+ vec := runtime_getAuxv()
+ vecLen := len(vec)
+
+ if vecLen == 0 {
+ return nil, syscall.ENOENT
+ }
+
+ if vecLen%2 != 0 {
+ return nil, syscall.EINVAL
+ }
+
+ result := make([]uintptr, vecLen)
+ copy(result, vec)
+ return unsafe.Slice((*[2]uintptr)(unsafe.Pointer(&result[0])), vecLen/2), nil
+}
diff --git a/unix/auxv_linux_test.go b/unix/auxv_linux_test.go
new file mode 100644
index 0000000..928f3c9
--- /dev/null
+++ b/unix/auxv_linux_test.go
@@ -0,0 +1,23 @@
+// Copyright 2025 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 go1.21 && linux
+
+package unix_test
+
+import (
+ "testing"
+
+ "golang.org/x/sys/unix"
+)
+
+func TestAuxv(t *testing.T) {
+ vec, err := unix.Auxv()
+ if err != nil {
+ t.Fatalf("unexpected error: %v", err)
+ }
+ if len(vec) == 0 {
+ t.Errorf("got zero auxv entries on linux, expected > 0")
+ }
+}
diff --git a/unix/auxv_unsupported.go b/unix/auxv_unsupported.go
new file mode 100644
index 0000000..1200487
--- /dev/null
+++ b/unix/auxv_unsupported.go
@@ -0,0 +1,13 @@
+// Copyright 2025 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 !go1.21 && (aix || darwin || dragonfly || freebsd || linux || netbsd || openbsd || solaris || zos)
+
+package unix
+
+import "syscall"
+
+func Auxv() ([][2]uintptr, error) {
+ return nil, syscall.ENOTSUP
+}
