all: Add support for OpenBSD

README.md

@@ -44,6 +44,7 @@ Tier 2 platforms are supported by PureGo on a best-effort basis. Critical bugs o
 - **FreeBSD**: amd64<sup>3,4</sup>, arm64<sup>3,4</sup>
 - **Linux**: 386<sup>3</sup>, arm<sup>3</sup>, loong64<sup>2</sup>, ppc64le<sup>2</sup>, riscv64<sup>3</sup>, s390x<sup>3, 5</sup>
 - **NetBSD**: amd64<sup>3,4</sup>, arm64<sup>3,4</sup>
+- **OpenBSD**: amd64<sup>3,4</sup>, arm64<sup>3,4</sup>
 - **Windows**: 386<sup>3,6</sup>, arm<sup>3,6,7</sup>
 
 #### Support Notes

cgo.go

@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: Apache-2.0
 // SPDX-FileCopyrightText: 2022 The Ebitengine Authors
 
-//go:build cgo && (darwin || freebsd || linux || netbsd)
+//go:build cgo && (darwin || freebsd || linux || netbsd || openbsd)
 
 package purego
 

dlerror.go

@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: Apache-2.0
 // SPDX-FileCopyrightText: 2023 The Ebitengine Authors
 
-//go:build darwin || freebsd || linux || netbsd
+//go:build darwin || freebsd || linux || netbsd || openbsd
 
 package purego
 

dlfcn.go

@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: Apache-2.0
 // SPDX-FileCopyrightText: 2022 The Ebitengine Authors
 
-//go:build (darwin || freebsd || linux || netbsd) && !android && !faketime
+//go:build (darwin || freebsd || linux || netbsd || openbsd) && !android && !faketime
 
 package purego
 

dlfcn_nocgo_openbsd.go

@@ -0,0 +1,18 @@
+// SPDX-License-Identifier: Apache-2.0
+// SPDX-FileCopyrightText: 2026 The Ebitengine Authors
+
+//go:build !cgo
+
+package purego
+
+// OpenBSD keeps dlopen and friends in libc -- there is no libdl -- and ships
+// no unversioned libc.so FILE: /usr/lib holds libc.so.103.0 and nothing else.
+// "libc.so" is still the right name to write here: the Go linker emits it as a
+// DT_NEEDED and OpenBSD's ld.so resolves an unversioned soname to the highest
+// version present. The Go runtime itself does exactly this in
+// runtime/sys_openbsd.go, which is the proof that it works.
+
+//go:cgo_import_dynamic purego_dlopen dlopen "libc.so"
+//go:cgo_import_dynamic purego_dlsym dlsym "libc.so"
+//go:cgo_import_dynamic purego_dlerror dlerror "libc.so"
+//go:cgo_import_dynamic purego_dlclose dlclose "libc.so"

dlfcn_openbsd.go

@@ -0,0 +1,18 @@
+// SPDX-License-Identifier: Apache-2.0
+// SPDX-FileCopyrightText: 2026 The Ebitengine Authors
+
+package purego
+
+// Source for constants: https://github.com/openbsd/src/blob/master/include/dlfcn.h
+//
+// Read from /usr/include/dlfcn.h on OpenBSD 7.9/arm64 rather than copied from
+// another BSD: they happen to agree with NetBSD's, and checking is cheaper
+// than finding out they had stopped agreeing.
+const (
+	intSize      = 32 << (^uint(0) >> 63) // 32 or 64
+	RTLD_DEFAULT = 1<<intSize - 2         // Pseudo-handle for dlsym so search for any loaded symbol
+	RTLD_LAZY    = 0x00000001             // Relocations are performed at an implementation-dependent time.
+	RTLD_NOW     = 0x00000002             // Relocations are performed when the object is loaded.
+	RTLD_LOCAL   = 0x00000000             // All symbols are not made available for relocation processing by other modules.
+	RTLD_GLOBAL  = 0x00000100             // All symbols are available for relocation processing of other modules.
+)

dlfcn_stubs.s

@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: Apache-2.0
 // SPDX-FileCopyrightText: 2022 The Ebitengine Authors
 
-//go:build darwin || !cgo && (freebsd || linux || netbsd) && !faketime
+//go:build darwin || !cgo && (freebsd || linux || netbsd || openbsd) && !faketime
 
 #include "textflag.h"
 

dlfcn_test.go

@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: Apache-2.0
 // SPDX-FileCopyrightText: 2023 The Ebitengine Authors
 
-//go:build darwin || freebsd || linux || netbsd
+//go:build darwin || freebsd || linux || netbsd || openbsd
 
 package purego_test
 

examples/libc/main.go

@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: Apache-2.0
 // SPDX-FileCopyrightText: 2022 The Ebitengine Authors
 
-//go:build darwin || freebsd || linux || netbsd || windows
+//go:build darwin || freebsd || linux || netbsd || openbsd || windows
 
 package main
 

examples/libc/main_unix.go

@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: Apache-2.0
 // SPDX-FileCopyrightText: 2023 The Ebitengine Authors
 
-//go:build darwin || freebsd || linux || netbsd
+//go:build darwin || freebsd || linux || netbsd || openbsd
 
 package main
 

export_test.go

@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: Apache-2.0
 // SPDX-FileCopyrightText: 2026 The Ebitengine Authors
 
-//go:build darwin || freebsd || linux || netbsd || windows
+//go:build darwin || freebsd || linux || netbsd || openbsd || windows
 
 package purego
 

func.go

@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: Apache-2.0
 // SPDX-FileCopyrightText: 2022 The Ebitengine Authors
 
-//go:build darwin || freebsd || linux || netbsd || windows
+//go:build darwin || freebsd || linux || netbsd || openbsd || windows
 
 package purego
 

func_test.go

@@ -34,7 +34,10 @@ func getSystemLibrary() (string, error) {
 		return "libc.so.7", nil
 	case "linux":
 		return "libc.so.6", nil
-	case "netbsd":
+	case "netbsd", "openbsd":
+		// Neither ships an unversioned libc.so FILE, but ld.so resolves the
+		// soname: on OpenBSD 7.9 this opens libc.so.103.0 and returns the
+		// same handle as naming the versioned file directly.
 		return "libc.so", nil
 	case "windows":
 		return "ucrtbase.dll", nil

go_runtime.go

@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: Apache-2.0
 // SPDX-FileCopyrightText: 2022 The Ebitengine Authors
 
-//go:build darwin || freebsd || linux || netbsd || windows
+//go:build darwin || freebsd || linux || netbsd || openbsd || windows
 
 package purego
 

internal/cgo/dlfcn_cgo_unix.go

@@ -1,12 +1,12 @@
 // SPDX-License-Identifier: Apache-2.0
 // SPDX-FileCopyrightText: 2024 The Ebitengine Authors
 
-//go:build freebsd || linux || netbsd
+//go:build freebsd || linux || netbsd || openbsd
 
 package cgo
 
 /*
-#cgo !netbsd LDFLAGS: -ldl
+#cgo !netbsd,!openbsd LDFLAGS: -ldl
 
 #include <dlfcn.h>
 #include <stdlib.h>

internal/cgo/syscall_cgo_unix.go

@@ -1,15 +1,15 @@
 // SPDX-License-Identifier: Apache-2.0
 // SPDX-FileCopyrightText: 2022 The Ebitengine Authors
 
-//go:build freebsd || (linux && !(386 || amd64 || arm || arm64 || loong64 || ppc64le || riscv64)) || netbsd
+//go:build freebsd || (linux && !(386 || amd64 || arm || arm64 || loong64 || ppc64le || riscv64)) || netbsd || openbsd
 
 package cgo
 
 // this file is placed inside internal/cgo and not package purego
 // because Cgo and assembly files can't be in the same package.
 
 /*
-#cgo !netbsd LDFLAGS: -ldl
+#cgo !netbsd,!openbsd LDFLAGS: -ldl
 
 #include <stdint.h>
 #include <dlfcn.h>

internal/fakecgo/callbacks.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 !cgo && (darwin || freebsd || linux || netbsd)
+//go:build !cgo && (darwin || freebsd || linux || netbsd || openbsd)
 
 package fakecgo
 

internal/fakecgo/doc.go

@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: Apache-2.0
 // SPDX-FileCopyrightText: 2022 The Ebitengine Authors
 
-//go:build !cgo && (darwin || freebsd || linux || netbsd)
+//go:build !cgo && (darwin || freebsd || linux || netbsd || openbsd)
 
 // Package fakecgo implements the Cgo runtime (runtime/cgo) entirely in Go.
 // This allows code that calls into C to function properly when CGO_ENABLED=0.

internal/fakecgo/fakecgo.go

@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: Apache-2.0
 // SPDX-FileCopyrightText: 2025 The Ebitengine Authors
 
-//go:build !cgo && (darwin || freebsd || linux || netbsd)
+//go:build !cgo && (darwin || freebsd || linux || netbsd || openbsd)
 
 package fakecgo
 

internal/fakecgo/gen.go

@@ -120,7 +120,7 @@ var (
 		{"sigfillset", [5]Arg{{"set", "*sigset_t"}}, "int32", nil},
 		{"nanosleep", [5]Arg{{"ts", "*syscall.Timespec"}, {"rem", "*syscall.Timespec"}}, "int32", nil},
 		{"abort", [5]Arg{}, "", nil},
-		{"sigaltstack", [5]Arg{{"ss", "*stack_t"}, {"old_ss", "*stack_t"}}, "int32", []string{"netbsd"}},
+		{"sigaltstack", [5]Arg{{"ss", "*stack_t"}, {"old_ss", "*stack_t"}}, "int32", []string{"netbsd", "openbsd"}},
 		{"__errno_location", [5]Arg{}, "uintptr", []string{"linux"}},
 		{"setegid", [5]Arg{{"egid", "uint32"}}, "int32", []string{"linux"}},
 		{"seteuid", [5]Arg{{"euid", "uint32"}}, "int32", []string{"linux"}},
@@ -139,9 +139,9 @@ var (
 		{"pthread_sigmask", [5]Arg{{"how", "sighow"}, {"ign", "*sigset_t"}, {"oset", "*sigset_t"}}, "int32", nil},
 		{"pthread_self", [5]Arg{}, "pthread_t", []string{"darwin"}},
 		{"pthread_get_stacksize_np", [5]Arg{{"thread", "pthread_t"}}, "size_t", []string{"darwin"}},
-		{"pthread_attr_getstacksize", [5]Arg{{"attr", "*pthread_attr_t"}, {"stacksize", "*size_t"}}, "int32", []string{"linux", "freebsd", "netbsd"}},
+		{"pthread_attr_getstacksize", [5]Arg{{"attr", "*pthread_attr_t"}, {"stacksize", "*size_t"}}, "int32", []string{"linux", "freebsd", "netbsd", "openbsd"}},
 		{"pthread_attr_setstacksize", [5]Arg{{"attr", "*pthread_attr_t"}, {"size", "size_t"}}, "int32", []string{"darwin"}},
-		{"pthread_attr_destroy", [5]Arg{{"attr", "*pthread_attr_t"}}, "int32", []string{"linux", "freebsd", "netbsd"}},
+		{"pthread_attr_destroy", [5]Arg{{"attr", "*pthread_attr_t"}}, "int32", []string{"linux", "freebsd", "netbsd", "openbsd"}},
 		{"pthread_mutex_lock", [5]Arg{{"mutex", "*pthread_mutex_t"}}, "int32", nil},
 		{"pthread_mutex_unlock", [5]Arg{{"mutex", "*pthread_mutex_t"}}, "int32", nil},
 		{"pthread_cond_broadcast", [5]Arg{{"cond", "*pthread_cond_t"}}, "int32", nil},
@@ -154,7 +154,7 @@ var funcs = map[string]any{
 	"imports":   imports,
 }
 
-var GOOSes = []string{"darwin", "freebsd", "linux", "netbsd"}
+var GOOSes = []string{"darwin", "freebsd", "linux", "netbsd", "openbsd"}
 
 func imports(symbols []Symbol) string {
 	if len(symbols) == 0 {
@@ -275,6 +275,9 @@ func run() error {
 		case "netbsd":
 			libcSO = "libc.so"
 			pthreadSO = "libpthread.so"
+		case "openbsd":
+			libcSO = "libc.so"
+			pthreadSO = "libpthread.so"
 		default:
 			return fmt.Errorf("unsupported OS: %s", goos)
 		}

internal/fakecgo/go_libinit.go

@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: Apache-2.0
 // SPDX-FileCopyrightText: 2022 The Ebitengine Authors
 
-//go:build !cgo && (darwin || freebsd || linux || netbsd)
+//go:build !cgo && (darwin || freebsd || linux || netbsd || openbsd)
 
 package fakecgo
 

internal/fakecgo/go_openbsd.go

@@ -0,0 +1,83 @@
+// Copyright 2011 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 !cgo && (amd64 || arm64)
+
+package fakecgo
+
+import "unsafe"
+
+//go:nosplit
+func _cgo_sys_thread_start(ts *ThreadStart) {
+	var attr pthread_attr_t
+	var ign, oset sigset_t
+	var p pthread_t
+	var size size_t
+	var err int
+
+	// fprintf(stderr, "runtime/cgo: _cgo_sys_thread_start: fn=%p, g=%p\n", ts->fn, ts->g); // debug
+	sigfillset(&ign)
+	pthread_sigmask(SIG_SETMASK, &ign, &oset)
+
+	pthread_attr_init(&attr)
+	pthread_attr_getstacksize(&attr, &size)
+	// Leave stacklo=0 and set stackhi=size; mstart will do the rest.
+	ts.g.stackhi = uintptr(size)
+
+	err = _cgo_try_pthread_create(&p, &attr, unsafe.Pointer(threadentry_trampolineABI0), ts)
+
+	pthread_sigmask(SIG_SETMASK, &oset, nil)
+
+	if err != 0 {
+		print("fakecgo: pthread_create failed: ")
+		println(err)
+		abort()
+	}
+}
+
+// threadentry_trampolineABI0 maps the C ABI to Go ABI then calls the Go function
+//
+//go:linkname x_threadentry_trampoline threadentry_trampoline
+var x_threadentry_trampoline byte
+var threadentry_trampolineABI0 = &x_threadentry_trampoline
+
+//go:nosplit
+func threadentry(v unsafe.Pointer) unsafe.Pointer {
+	var ss stack_t
+	ts := *(*ThreadStart)(v)
+	free(v)
+
+	// On OpenBSD, a new thread inherits the signal stack of the
+	// creating thread. That confuses minit, so we remove that
+	// signal stack here before calling the regular mstart. It's
+	// a bit baroque to remove a signal stack here only to add one
+	// in minit, but it's a simple change that keeps OpenBSD
+	// working like other OS's. At this point all signals are
+	// blocked, so there is no race.
+	ss.ss_flags = SS_DISABLE
+	sigaltstack(&ss, nil)
+
+	setg_trampoline(setg_func, uintptr(unsafe.Pointer(ts.g)))
+
+	callThreadEntryFn(ts.fn)
+
+	return nil
+}
+
+// here we will store a pointer to the provided setg func
+var setg_func uintptr
+
+//go:nosplit
+func x_cgo_init(g *G, setg uintptr) {
+	var size size_t
+	var attr pthread_attr_t
+
+	setg_func = setg
+	pthread_attr_init(&attr)
+	pthread_attr_getstacksize(&attr, &size)
+	// runtime/cgo uses __builtin_frame_address(0) instead of `uintptr(unsafe.Pointer(&size))`
+	// but this should be OK since we are taking the address of the first variable in this function.
+	g.stacklo = uintptr(unsafe.Pointer(&size)) - uintptr(size) + 4096
+	pthread_attr_destroy(&attr)
+}

internal/fakecgo/go_setenv.go

@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: Apache-2.0
 // SPDX-FileCopyrightText: 2022 The Ebitengine Authors
 
-//go:build !cgo && (darwin || freebsd || linux || netbsd)
+//go:build !cgo && (darwin || freebsd || linux || netbsd || openbsd)
 
 package fakecgo
 

internal/fakecgo/go_util.go

@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: Apache-2.0
 // SPDX-FileCopyrightText: 2022 The Ebitengine Authors
 
-//go:build !cgo && (darwin || freebsd || linux || netbsd)
+//go:build !cgo && (darwin || freebsd || linux || netbsd || openbsd)
 
 package fakecgo
 

internal/fakecgo/iscgo.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 !cgo && (darwin || freebsd || linux || netbsd)
+//go:build !cgo && (darwin || freebsd || linux || netbsd || openbsd)
 
 // The runtime package contains an uninitialized definition
 // for runtime·iscgo. Override it to tell the runtime we're here.

internal/fakecgo/libcgo.go

@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: Apache-2.0
 // SPDX-FileCopyrightText: 2022 The Ebitengine Authors
 
-//go:build !cgo && (darwin || freebsd || linux || netbsd)
+//go:build !cgo && (darwin || freebsd || linux || netbsd || openbsd)
 
 package fakecgo