internal/syscall/unix: fix PosixFallocate on 32-bit freebsd

Follow-up for CL 478035 which broke the freebsd/396 builders:

https://build.golang.org/log/e6e442cd353024c4fdb64111ad0bcbf5b25b8ecd

64-bit syscall arguments need to be passed as two 32-bit arguments on
32-bit freebsd.

Change-Id: Idf4fdf4ab7d112bc2cf95b075a5a29f221bffcb6
Reviewed-on: https://go-review.googlesource.com/c/go/+/479715
Reviewed-by: Ian Lance Taylor <iant@google.com>
Auto-Submit: Tobias Klauser <tobias.klauser@gmail.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>

2 files changed, 22 insertions, 0 deletions

diff --git a/src/internal/syscall/unix/fallocate_freebsd_32bit.go b/src/internal/syscall/unix/fallocate_freebsd_32bit.go
new file mode 100644
index 0000000000..d821eea81c
--- /dev/null
+++ b/src/internal/syscall/unix/fallocate_freebsd_32bit.go
@@ -0,0 +1,20 @@
+// 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 freebsd && (386 || arm)
+
+package unix
+
+import "syscall"
+
+// FreeBSD posix_fallocate system call number.
+const posixFallocateTrap uintptr = 530
+
+func PosixFallocate(fd int, off int64, size int64) error {
+	_, _, errno := syscall.Syscall6(posixFallocateTrap, uintptr(fd), uintptr(off), uintptr(off>>32), uintptr(size), uintptr(size>>32), 0)
+	if errno != 0 {
+		return errno
+	}
+	return nil
+}
diff --git a/src/internal/syscall/unix/fallocate_freebsd.go b/src/internal/syscall/unix/fallocate_freebsd_64bit.go
index 6c3e80118b..f1ef6e347c 100644
--- a/src/internal/syscall/unix/fallocate_freebsd.go
+++ b/src/internal/syscall/unix/fallocate_freebsd_64bit.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 freebsd && (amd64 || arm64 || riscv64)
+
 package unix
 
 import "syscall"