internal/poll, internal/syscall/unix, net, runtime: convert openbsd (except mips64) to direct libc calls

Call libc wrappers directly rather than calling using syscall(2).

Updates golang/go#36435

Change-Id: I40be410c7472f7d89cbec2ebdc7c841c7726ca4a
Reviewed-on: https://go-review.googlesource.com/c/go/+/425637
Reviewed-by: David Chase <drchase@google.com>
Reviewed-by: Heschi Kreinick <heschi@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
Reviewed-by: Joel Sing <joel@sing.id.au>

7 files changed, 39 insertions, 20 deletions

diff --git a/src/internal/syscall/unix/at.go b/src/internal/syscall/unix/at.go
index 965162e3d2..876ca9ff57 100644
--- a/src/internal/syscall/unix/at.go
+++ b/src/internal/syscall/unix/at.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 linux || openbsd || netbsd || dragonfly
+//go:build dragonfly || linux || netbsd || (openbsd && mips64)
 
 package unix
 
diff --git a/src/internal/syscall/unix/at_fstatat.go b/src/internal/syscall/unix/at_fstatat.go
index 25318d2014..8f25fe9f64 100644
--- a/src/internal/syscall/unix/at_fstatat.go
+++ b/src/internal/syscall/unix/at_fstatat.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 (linux && !loong64) || openbsd || netbsd || dragonfly
+//go:build dragonfly || (linux && !loong64) || netbsd || (openbsd && mips64)
 
 package unix
 
diff --git a/src/internal/syscall/unix/at_darwin.go b/src/internal/syscall/unix/at_libc2.go
index a88a27e0c6..93d0cf4443 100644
--- a/src/internal/syscall/unix/at_darwin.go
+++ b/src/internal/syscall/unix/at_libc2.go
@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build darwin || (openbsd && !mips64)
+
 package unix
 
 import (
diff --git a/src/internal/syscall/unix/getentropy_openbsd.go b/src/internal/syscall/unix/getentropy_openbsd.go
index d5caa8095a..ad0914da90 100644
--- a/src/internal/syscall/unix/getentropy_openbsd.go
+++ b/src/internal/syscall/unix/getentropy_openbsd.go
@@ -1,25 +1,17 @@
-// Copyright 2016 The Go Authors. All rights reserved.
+// Copyright 2022 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
+//go:build openbsd && !mips64
 
-import (
-	"syscall"
-	"unsafe"
-)
+package unix
 
-// getentropy(2)'s syscall number, from /usr/src/sys/kern/syscalls.master
-const entropyTrap uintptr = 7
+import _ "unsafe" // for linkname
 
 // GetEntropy calls the OpenBSD getentropy system call.
 func GetEntropy(p []byte) error {
-	_, _, errno := syscall.Syscall(entropyTrap,
-		uintptr(unsafe.Pointer(&p[0])),
-		uintptr(len(p)),
-		0)
-	if errno != 0 {
-		return errno
-	}
-	return nil
+	return getentropy(p)
 }
+
+//go:linkname getentropy syscall.getentropy
+func getentropy(p []byte) error
diff --git a/src/internal/syscall/unix/getentropy_openbsd_mips64.go b/src/internal/syscall/unix/getentropy_openbsd_mips64.go
new file mode 100644
index 0000000000..d5caa8095a
--- /dev/null
+++ b/src/internal/syscall/unix/getentropy_openbsd_mips64.go
@@ -0,0 +1,25 @@
+// Copyright 2016 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 (
+	"syscall"
+	"unsafe"
+)
+
+// getentropy(2)'s syscall number, from /usr/src/sys/kern/syscalls.master
+const entropyTrap uintptr = 7
+
+// GetEntropy calls the OpenBSD getentropy system call.
+func GetEntropy(p []byte) error {
+	_, _, errno := syscall.Syscall(entropyTrap,
+		uintptr(unsafe.Pointer(&p[0])),
+		uintptr(len(p)),
+		0)
+	if errno != 0 {
+		return errno
+	}
+	return nil
+}
diff --git a/src/internal/syscall/unix/nonblocking.go b/src/internal/syscall/unix/nonblocking.go
index 9e5f0fb4a2..a0becd1e01 100644
--- a/src/internal/syscall/unix/nonblocking.go
+++ b/src/internal/syscall/unix/nonblocking.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 dragonfly || freebsd || linux || netbsd || openbsd
+//go:build dragonfly || freebsd || linux || netbsd || (openbsd && mips64)
 
 package unix
 
diff --git a/src/internal/syscall/unix/nonblocking_libc.go b/src/internal/syscall/unix/nonblocking_libc.go
index 84940714c3..bff6684962 100644
--- a/src/internal/syscall/unix/nonblocking_libc.go
+++ b/src/internal/syscall/unix/nonblocking_libc.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 || darwin || solaris
+//go:build aix || darwin || (openbsd && !mips64) || solaris
 
 package unix