cmd/link/internal/ld, internal/syscall/unix: use posix_fallocate on netbsd

The posix_fallocate system call is available since NetBSD 7.0, see
https://man.netbsd.org/posix_fallocate.2

Re-use the syscall wrappers already in place for freebsd. Note that
posix_fallocate on netbsd also returns the result in r1 rather than in
errno:

> If successful, posix_fallocate() returns zero. It returns an error on failure, without
> setting errno.

Source: https://man.netbsd.org/posix_fallocate.2#RETURN%20VALUES

Cq-Include-Trybots: luci.golang.try:gotip-netbsd-arm64
Change-Id: Iaa1f6a805d511645da7f1d2737235bfd42da3407
Reviewed-on: https://go-review.googlesource.com/c/go/+/480475
Reviewed-by: Cherry Mui <cherryyz@google.com>
Reviewed-by: Benny Siegert <bsiegert@gmail.com>
Auto-Submit: Tobias Klauser <tobias.klauser@gmail.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>

4 files changed, 19 insertions, 11 deletions

diff --git a/src/internal/syscall/unix/at_sysnum_netbsd.go b/src/internal/syscall/unix/at_sysnum_netbsd.go
index b59b5e0cf9..db17852b74 100644
--- a/src/internal/syscall/unix/at_sysnum_netbsd.go
+++ b/src/internal/syscall/unix/at_sysnum_netbsd.go
@@ -7,16 +7,17 @@ package unix
 import "syscall"
 
 const (
-	unlinkatTrap   uintptr = syscall.SYS_UNLINKAT
-	openatTrap     uintptr = syscall.SYS_OPENAT
-	fstatatTrap    uintptr = syscall.SYS_FSTATAT
-	readlinkatTrap uintptr = syscall.SYS_READLINKAT
-	mkdiratTrap    uintptr = syscall.SYS_MKDIRAT
-	fchmodatTrap   uintptr = syscall.SYS_FCHMODAT
-	fchownatTrap   uintptr = syscall.SYS_FCHOWNAT
-	renameatTrap   uintptr = syscall.SYS_RENAMEAT
-	linkatTrap     uintptr = syscall.SYS_LINKAT
-	symlinkatTrap  uintptr = syscall.SYS_SYMLINKAT
+	unlinkatTrap       uintptr = syscall.SYS_UNLINKAT
+	openatTrap         uintptr = syscall.SYS_OPENAT
+	fstatatTrap        uintptr = syscall.SYS_FSTATAT
+	readlinkatTrap     uintptr = syscall.SYS_READLINKAT
+	mkdiratTrap        uintptr = syscall.SYS_MKDIRAT
+	fchmodatTrap       uintptr = syscall.SYS_FCHMODAT
+	fchownatTrap       uintptr = syscall.SYS_FCHOWNAT
+	renameatTrap       uintptr = syscall.SYS_RENAMEAT
+	linkatTrap         uintptr = syscall.SYS_LINKAT
+	symlinkatTrap      uintptr = syscall.SYS_SYMLINKAT
+	posixFallocateTrap uintptr = 479
 )
 
 const (
diff --git a/src/internal/syscall/unix/fallocate_freebsd_386.go b/src/internal/syscall/unix/fallocate_bsd_386.go
index 535b23dbc5..1dcdff4a53 100644
--- a/src/internal/syscall/unix/fallocate_freebsd_386.go
+++ b/src/internal/syscall/unix/fallocate_bsd_386.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 || netbsd) && 386
+
 package unix
 
 import "syscall"
@@ -9,6 +11,7 @@ import "syscall"
 func PosixFallocate(fd int, off int64, size int64) error {
 	// If successful, posix_fallocate() returns zero. It returns an error on failure, without
 	// setting errno. See https://man.freebsd.org/cgi/man.cgi?query=posix_fallocate&sektion=2&n=1
+	// and https://man.netbsd.org/posix_fallocate.2#RETURN%20VALUES
 	r1, _, _ := syscall.Syscall6(posixFallocateTrap, uintptr(fd), uintptr(off), uintptr(off>>32), uintptr(size), uintptr(size>>32), 0)
 	if r1 != 0 {
 		return syscall.Errno(r1)
diff --git a/src/internal/syscall/unix/fallocate_freebsd_64bit.go b/src/internal/syscall/unix/fallocate_bsd_64bit.go
index a9d52283f0..177bb48382 100644
--- a/src/internal/syscall/unix/fallocate_freebsd_64bit.go
+++ b/src/internal/syscall/unix/fallocate_bsd_64bit.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 freebsd && (amd64 || arm64 || riscv64)
+//go:build (freebsd || netbsd) && (amd64 || arm64 || riscv64)
 
 package unix
 
@@ -11,6 +11,7 @@ import "syscall"
 func PosixFallocate(fd int, off int64, size int64) error {
 	// If successful, posix_fallocate() returns zero. It returns an error on failure, without
 	// setting errno. See https://man.freebsd.org/cgi/man.cgi?query=posix_fallocate&sektion=2&n=1
+	// and https://man.netbsd.org/posix_fallocate.2#RETURN%20VALUES
 	r1, _, _ := syscall.Syscall(posixFallocateTrap, uintptr(fd), uintptr(off), uintptr(size))
 	if r1 != 0 {
 		return syscall.Errno(r1)
diff --git a/src/internal/syscall/unix/fallocate_freebsd_arm.go b/src/internal/syscall/unix/fallocate_bsd_arm.go
index 1ded50f3b9..15e99d02b1 100644
--- a/src/internal/syscall/unix/fallocate_freebsd_arm.go
+++ b/src/internal/syscall/unix/fallocate_bsd_arm.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 || netbsd) && arm
+
 package unix
 
 import "syscall"
@@ -9,6 +11,7 @@ import "syscall"
 func PosixFallocate(fd int, off int64, size int64) error {
 	// If successful, posix_fallocate() returns zero. It returns an error on failure, without
 	// setting errno. See https://man.freebsd.org/cgi/man.cgi?query=posix_fallocate&sektion=2&n=1
+	// and https://man.netbsd.org/posix_fallocate.2#RETURN%20VALUES
 	//
 	// The padding 0 argument is needed because the ARM calling convention requires that if an
 	// argument (off in this case) needs double-word alignment (8-byte), the NCRN (next core