4 files changed, 41 insertions, 59 deletions
diff --git a/src/crypto/rand/rand_getentropy.go b/src/crypto/rand/rand_getentropy.go
index 68f921b0fc..210250411e 100644
--- a/src/crypto/rand/rand_getentropy.go
+++ b/src/crypto/rand/rand_getentropy.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 (darwin && !ios) || openbsd
+//go:build (darwin && !ios) || openbsd || netbsd
 
 package rand
 
diff --git a/src/crypto/rand/rand_getrandom.go b/src/crypto/rand/rand_getrandom.go
index 46c4133a73..09e9ae82b0 100644
--- a/src/crypto/rand/rand_getrandom.go
+++ b/src/crypto/rand/rand_getrandom.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 || solaris
+//go:build dragonfly || freebsd || linux || solaris
 
 package rand
 
@@ -21,7 +21,7 @@ func init() {
 		//     is returned by a single call to getrandom() on systems where int
 		//     has a size of 32 bits.
 		maxGetRandomRead = (1 << 25) - 1
-	case "dragonfly", "freebsd", "illumos", "netbsd", "solaris":
+	case "dragonfly", "freebsd", "illumos", "solaris":
 		maxGetRandomRead = 1 << 8
 	default:
 		panic("no maximum specified for GetRandom")
diff --git a/src/internal/syscall/unix/getentropy_netbsd.go b/src/internal/syscall/unix/getentropy_netbsd.go
new file mode 100644
index 0000000000..7e8382331c
--- /dev/null
+++ b/src/internal/syscall/unix/getentropy_netbsd.go
@@ -0,0 +1,38 @@
+// Copyright 2023 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 netbsd
+
+package unix
+
+import (
+	"syscall"
+	"unsafe"
+)
+
+const (
+	_CTL_KERN = 1
+
+	_KERN_ARND = 81
+)
+
+func GetEntropy(p []byte) error {
+	mib := [2]uint32{_CTL_KERN, _KERN_ARND}
+	n := uintptr(len(p))
+	_, _, errno := syscall.Syscall6(
+		syscall.SYS___SYSCTL,
+		uintptr(unsafe.Pointer(&mib[0])),
+		uintptr(len(mib)),
+		uintptr(unsafe.Pointer(&p[0])), // olddata
+		uintptr(unsafe.Pointer(&n)),	// &oldlen
+		uintptr(unsafe.Pointer(nil)),	// newdata
+		0)				// newlen
+	if errno != 0 {
+		return syscall.Errno(errno)
+	}
+	if n != uintptr(len(p)) {
+		return syscall.EINVAL
+	}
+	return nil
+}
diff --git a/src/internal/syscall/unix/getrandom_netbsd.go b/src/internal/syscall/unix/getrandom_netbsd.go
deleted file mode 100644
index c83e3b21a5..0000000000
--- a/src/internal/syscall/unix/getrandom_netbsd.go
+++ /dev/null
@@ -1,56 +0,0 @@
-// Copyright 2023 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 (
-	"sync"
-	"sync/atomic"
-	"syscall"
-	"unsafe"
-)
-
-// NetBSD getrandom system call number.
-const getrandomTrap uintptr = 91
-
-var getrandomUnsupported atomic.Bool
-
-// GetRandomFlag is a flag supported by the getrandom system call.
-type GetRandomFlag uintptr
-
-// GetRandom calls the getrandom system call.
-func GetRandom(p []byte, flags GetRandomFlag) (n int, err error) {
-	if len(p) == 0 {
-		return 0, nil
-	}
-	if getrandomUnsupported.Load() {
-		return 0, syscall.ENOSYS
-	}
-	// getrandom(2) was added in NetBSD 10.0
-	if getOSRevision() < 1000000000 {
-		getrandomUnsupported.Store(true)
-		return 0, syscall.ENOSYS
-	}
-	r1, _, errno := syscall.Syscall(getrandomTrap,
-		uintptr(unsafe.Pointer(&p[0])),
-		uintptr(len(p)),
-		uintptr(flags))
-	if errno != 0 {
-		if errno == syscall.ENOSYS {
-			getrandomUnsupported.Store(true)
-		}
-		return 0, errno
-	}
-	return int(r1), nil
-}
-
-var (
-	osrevisionOnce sync.Once
-	osrevision     uint32
-)
-
-func getOSRevision() uint32 {
-	osrevisionOnce.Do(func() { osrevision, _ = syscall.SysctlUint32("kern.osrevision") })
-	return osrevision
-}