From: Brad Smith <brad@comstyle.com>
Subject: Re: Go - getexecpath() support
To: ports@openbsd.org
Cc: Joel Sing <jsing@openbsd.org>
Date: Wed, 7 Oct 2026 18:30:20 -0400

ping.

On 2026-10-04 5:45 a.m., Brad Smith wrote:
> Here is a diff for Go to make use of getexecpath()
> for os.Executable().
>
> Tested on aarch64 and amd64.
>
>
> Index: Makefile
> ===================================================================
> RCS file: /cvs/ports/lang/go/Makefile,v
> retrieving revision 1.184
> diff -u -p -u -p -r1.184 Makefile
> --- Makefile	16 Sep 2026 16:16:51 -0000	1.184
> +++ Makefile	4 Oct 2026 09:37:19 -0000
> @@ -10,6 +10,7 @@ COMMENT =		Go programming language
>   VERSION =		1.27.1
>   DISTNAME =		go${VERSION}.src
>   PKGNAME =		go-${VERSION}
> +REVISION =		0
>   PKGSPEC =		${FULLPKGNAME:S/go-/go-=/}
>   
>   CATEGORIES =		lang
> Index: patches/patch-src_internal_syscall_unix_asm_openbsd_s
> ===================================================================
> RCS file: patches/patch-src_internal_syscall_unix_asm_openbsd_s
> diff -N patches/patch-src_internal_syscall_unix_asm_openbsd_s
> --- /dev/null	1 Jan 1970 00:00:00 -0000
> +++ patches/patch-src_internal_syscall_unix_asm_openbsd_s	4 Oct 2026 09:37:19 -0000
> @@ -0,0 +1,11 @@
> +- Use getexecpath() for os.Executable()
> +
> +Index: src/internal/syscall/unix/asm_openbsd.s
> +--- src/internal/syscall/unix/asm_openbsd.s.orig
> ++++ src/internal/syscall/unix/asm_openbsd.s
> +@@ -22,3 +22,5 @@ TEXT ·libc_linkat_trampoline(SB),NOSPLI
> +         JMP	libc_linkat(SB)
> + TEXT ·libc_symlinkat_trampoline(SB),NOSPLIT,$0-0
> +         JMP	libc_symlinkat(SB)
> ++TEXT ·libc_getexecpath_trampoline(SB),NOSPLIT,$0-0
> ++        JMP	libc_getexecpath(SB)
> Index: patches/patch-src_internal_syscall_unix_getexecpath_openbsd_go
> ===================================================================
> RCS file: patches/patch-src_internal_syscall_unix_getexecpath_openbsd_go
> diff -N patches/patch-src_internal_syscall_unix_getexecpath_openbsd_go
> --- /dev/null	1 Jan 1970 00:00:00 -0000
> +++ patches/patch-src_internal_syscall_unix_getexecpath_openbsd_go	4 Oct 2026 09:37:19 -0000
> @@ -0,0 +1,31 @@
> +- Use getexecpath() for os.Executable()
> +
> +Index: src/internal/syscall/unix/getexecpath_openbsd.go
> +--- src/internal/syscall/unix/getexecpath_openbsd.go.orig
> ++++ src/internal/syscall/unix/getexecpath_openbsd.go
> +@@ -0,0 +1,25 @@
> ++// Copyright 2026 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.
> ++
> ++package unix
> ++
> ++import (
> ++	"internal/abi"
> ++	"unsafe"
> ++)
> ++
> ++//go:cgo_import_dynamic libc_getexecpath getexecpath "libc.so"
> ++
> ++func libc_getexecpath_trampoline()
> ++
> ++// Getexecpath copies the absolute, canonicalized pathname of the
> ++// running executable into buf as a NUL-terminated string.
> ++func Getexecpath(buf []byte) error {
> ++	_, _, errno := syscall_syscall(abi.FuncPCABI0(libc_getexecpath_trampoline),
> ++		uintptr(unsafe.Pointer(unsafe.SliceData(buf))), uintptr(len(buf)), 0)
> ++	if errno != 0 {
> ++		return errno
> ++	}
> ++	return nil
> ++}
> Index: patches/patch-src_os_executable_openbsd_go
> ===================================================================
> RCS file: patches/patch-src_os_executable_openbsd_go
> diff -N patches/patch-src_os_executable_openbsd_go
> --- /dev/null	1 Jan 1970 00:00:00 -0000
> +++ patches/patch-src_os_executable_openbsd_go	4 Oct 2026 09:37:19 -0000
> @@ -0,0 +1,24 @@
> +- Use getexecpath() for os.Executable()
> +
> +Index: src/os/executable_openbsd.go
> +--- src/os/executable_openbsd.go.orig
> ++++ src/os/executable_openbsd.go
> +@@ -0,0 +1,18 @@
> ++// Copyright 2026 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.
> ++
> ++package os
> ++
> ++import (
> ++	"internal/bytealg"
> ++	"internal/syscall/unix"
> ++)
> ++
> ++func executable() (string, error) {
> ++	var buf [1024]byte // PATH_MAX; the kernel caps the path at this length
> ++	if err := unix.Getexecpath(buf[:]); err != nil {
> ++		return "", NewSyscallError("getexecpath", err)
> ++	}
> ++	return string(buf[:bytealg.IndexByte(buf[:], 0)]), nil
> ++}
> Index: patches/patch-src_os_executable_path_go
> ===================================================================
> RCS file: patches/patch-src_os_executable_path_go
> diff -N patches/patch-src_os_executable_path_go
> --- /dev/null	1 Jan 1970 00:00:00 -0000
> +++ patches/patch-src_os_executable_path_go	4 Oct 2026 09:37:19 -0000
> @@ -0,0 +1,14 @@
> +- Use getexecpath() for os.Executable()
> +
> +Index: src/os/executable_path.go
> +--- src/os/executable_path.go.orig
> ++++ src/os/executable_path.go
> +@@ -2,7 +2,7 @@
> + // Use of this source code is governed by a BSD-style
> + // license that can be found in the LICENSE file.
> +
> +-//go:build aix || openbsd
> ++//go:build aix
> +
> + package os
> +
> Index: patches/patch-src_os_executable_test_go
> ===================================================================
> RCS file: patches/patch-src_os_executable_test_go
> diff -N patches/patch-src_os_executable_test_go
> --- /dev/null	1 Jan 1970 00:00:00 -0000
> +++ patches/patch-src_os_executable_test_go	4 Oct 2026 09:37:19 -0000
> @@ -0,0 +1,25 @@
> +- Use getexecpath() for os.Executable()
> +
> +Index: src/os/executable_test.go
> +--- src/os/executable_test.go.orig
> ++++ src/os/executable_test.go
> +@@ -48,8 +48,8 @@ func TestExecutable(t *testing.T) {
> + 	// make child start with a relative program path
> + 	cmd.Dir = dir
> + 	cmd.Path = fn
> +-	if runtime.GOOS == "openbsd" || runtime.GOOS == "aix" {
> +-		// OpenBSD and AIX rely on argv[0]
> ++	if runtime.GOOS == "aix" {
> ++		// AIX relies on argv[0]
> + 	} else {
> + 		// forge argv[0] for child, so that we can verify we could correctly
> + 		// get real path of the executable without influenced by argv[0].
> +@@ -86,7 +86,7 @@ func TestExecutableDeleted(t *testing.T)
> + 	switch runtime.GOOS {
> + 	case "windows", "plan9":
> + 		t.Skipf("%v does not support deleting running binary", runtime.GOOS)
> +-	case "openbsd", "freebsd", "aix":
> ++	case "freebsd", "aix":
> + 		t.Skipf("%v does not support reading deleted binary name", runtime.GOOS)
> + 	}
> + 	t.Parallel()
> Index: pkg/PLIST
> ===================================================================
> RCS file: /cvs/ports/lang/go/pkg/PLIST,v
> retrieving revision 1.100
> diff -u -p -u -p -r1.100 PLIST
> --- pkg/PLIST	16 Sep 2026 16:16:51 -0000	1.100
> +++ pkg/PLIST	4 Oct 2026 09:37:20 -0000
> @@ -9188,6 +9188,7 @@ go/src/internal/syscall/unix/fchmodat_te
>   go/src/internal/syscall/unix/fcntl_js.go
>   go/src/internal/syscall/unix/fcntl_unix.go
>   go/src/internal/syscall/unix/fcntl_wasip1.go
> +go/src/internal/syscall/unix/getexecpath_openbsd.go
>   go/src/internal/syscall/unix/getrandom.go
>   go/src/internal/syscall/unix/getrandom_dragonfly.go
>   go/src/internal/syscall/unix/getrandom_freebsd.go
> @@ -10843,6 +10844,7 @@ go/src/os/executable_darwin.go
>   go/src/os/executable_dragonfly.go
>   go/src/os/executable_freebsd.go
>   go/src/os/executable_netbsd.go
> +go/src/os/executable_openbsd.go
>   go/src/os/executable_path.go
>   go/src/os/executable_plan9.go
>   go/src/os/executable_procfs.go