diff --git a/unix/fcntl.go b/unix/fcntl.go
index 58c6bfc70..6200876fb 100644
--- a/unix/fcntl.go
+++ b/unix/fcntl.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
 
 package unix
 
diff --git a/unix/syscall_openbsd.go b/unix/syscall_openbsd.go
index d2882ee04..b25343c71 100644
--- a/unix/syscall_openbsd.go
+++ b/unix/syscall_openbsd.go
@@ -166,6 +166,20 @@ func Getresgid() (rgid, egid, sgid int) {
 
 //sys	sysctl(mib []_C_int, old *byte, oldlen *uintptr, new *byte, newlen uintptr) (err error) = SYS___SYSCTL
 
+//sys	fcntl(fd int, cmd int, arg int) (n int, err error)
+//sys	fcntlPtr(fd int, cmd int, arg unsafe.Pointer) (n int, err error) = SYS_FCNTL
+
+// FcntlInt performs a fcntl syscall on fd with the provided command and argument.
+func FcntlInt(fd uintptr, cmd, arg int) (int, error) {
+	return fcntl(int(fd), cmd, arg)
+}
+
+// FcntlFlock performs a fcntl syscall for the F_GETLK, F_SETLK or F_SETLKW command.
+func FcntlFlock(fd uintptr, cmd int, lk *Flock_t) error {
+	_, err := fcntlPtr(int(fd), cmd, unsafe.Pointer(lk))
+	return err
+}
+
 //sys	ppoll(fds *PollFd, nfds int, timeout *Timespec, sigmask *Sigset_t) (n int, err error)
 
 func Ppoll(fds []PollFd, timeout *Timespec, sigmask *Sigset_t) (n int, err error) {
diff --git a/unix/zsyscall_openbsd_386.go b/unix/zsyscall_openbsd_386.go
index 88bfc2885..a1d061597 100644
--- a/unix/zsyscall_openbsd_386.go
+++ b/unix/zsyscall_openbsd_386.go
@@ -584,6 +584,32 @@ var libc_sysctl_trampoline_addr uintptr
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
+func fcntl(fd int, cmd int, arg int) (n int, err error) {
+	r0, _, e1 := syscall_syscall(libc_fcntl_trampoline_addr, uintptr(fd), uintptr(cmd), uintptr(arg))
+	n = int(r0)
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+var libc_fcntl_trampoline_addr uintptr
+
+//go:cgo_import_dynamic libc_fcntl fcntl "libc.so"
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
+func fcntlPtr(fd int, cmd int, arg unsafe.Pointer) (n int, err error) {
+	r0, _, e1 := syscall_syscall(libc_fcntl_trampoline_addr, uintptr(fd), uintptr(cmd), uintptr(arg))
+	n = int(r0)
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
 func ppoll(fds *PollFd, nfds int, timeout *Timespec, sigmask *Sigset_t) (n int, err error) {
 	r0, _, e1 := syscall_syscall6(libc_ppoll_trampoline_addr, uintptr(unsafe.Pointer(fds)), uintptr(nfds), uintptr(unsafe.Pointer(timeout)), uintptr(unsafe.Pointer(sigmask)), 0, 0)
 	n = int(r0)
diff --git a/unix/zsyscall_openbsd_386.s b/unix/zsyscall_openbsd_386.s
index 4cbeff171..41b561731 100644
--- a/unix/zsyscall_openbsd_386.s
+++ b/unix/zsyscall_openbsd_386.s
@@ -178,6 +178,11 @@ TEXT libc_sysctl_trampoline<>(SB),NOSPLIT,$0-0
 GLOBL	·libc_sysctl_trampoline_addr(SB), RODATA, $4
 DATA	·libc_sysctl_trampoline_addr(SB)/4, $libc_sysctl_trampoline<>(SB)
 
+TEXT libc_fcntl_trampoline<>(SB),NOSPLIT,$0-0
+	JMP	libc_fcntl(SB)
+GLOBL	·libc_fcntl_trampoline_addr(SB), RODATA, $4
+DATA	·libc_fcntl_trampoline_addr(SB)/4, $libc_fcntl_trampoline<>(SB)
+
 TEXT libc_ppoll_trampoline<>(SB),NOSPLIT,$0-0
 	JMP	libc_ppoll(SB)
 GLOBL	·libc_ppoll_trampoline_addr(SB), RODATA, $4
diff --git a/unix/zsyscall_openbsd_amd64.go b/unix/zsyscall_openbsd_amd64.go
index b8a67b99a..5b2a74097 100644
--- a/unix/zsyscall_openbsd_amd64.go
+++ b/unix/zsyscall_openbsd_amd64.go
@@ -584,6 +584,32 @@ var libc_sysctl_trampoline_addr uintptr
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
+func fcntl(fd int, cmd int, arg int) (n int, err error) {
+	r0, _, e1 := syscall_syscall(libc_fcntl_trampoline_addr, uintptr(fd), uintptr(cmd), uintptr(arg))
+	n = int(r0)
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+var libc_fcntl_trampoline_addr uintptr
+
+//go:cgo_import_dynamic libc_fcntl fcntl "libc.so"
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
+func fcntlPtr(fd int, cmd int, arg unsafe.Pointer) (n int, err error) {
+	r0, _, e1 := syscall_syscall(libc_fcntl_trampoline_addr, uintptr(fd), uintptr(cmd), uintptr(arg))
+	n = int(r0)
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
 func ppoll(fds *PollFd, nfds int, timeout *Timespec, sigmask *Sigset_t) (n int, err error) {
 	r0, _, e1 := syscall_syscall6(libc_ppoll_trampoline_addr, uintptr(unsafe.Pointer(fds)), uintptr(nfds), uintptr(unsafe.Pointer(timeout)), uintptr(unsafe.Pointer(sigmask)), 0, 0)
 	n = int(r0)
diff --git a/unix/zsyscall_openbsd_amd64.s b/unix/zsyscall_openbsd_amd64.s
index 1123f2757..4019a656f 100644
--- a/unix/zsyscall_openbsd_amd64.s
+++ b/unix/zsyscall_openbsd_amd64.s
@@ -178,6 +178,11 @@ TEXT libc_sysctl_trampoline<>(SB),NOSPLIT,$0-0
 GLOBL	·libc_sysctl_trampoline_addr(SB), RODATA, $8
 DATA	·libc_sysctl_trampoline_addr(SB)/8, $libc_sysctl_trampoline<>(SB)
 
+TEXT libc_fcntl_trampoline<>(SB),NOSPLIT,$0-0
+	JMP	libc_fcntl(SB)
+GLOBL	·libc_fcntl_trampoline_addr(SB), RODATA, $8
+DATA	·libc_fcntl_trampoline_addr(SB)/8, $libc_fcntl_trampoline<>(SB)
+
 TEXT libc_ppoll_trampoline<>(SB),NOSPLIT,$0-0
 	JMP	libc_ppoll(SB)
 GLOBL	·libc_ppoll_trampoline_addr(SB), RODATA, $8
diff --git a/unix/zsyscall_openbsd_arm.go b/unix/zsyscall_openbsd_arm.go
index af50a65c0..f6eda1344 100644
--- a/unix/zsyscall_openbsd_arm.go
+++ b/unix/zsyscall_openbsd_arm.go
@@ -584,6 +584,32 @@ var libc_sysctl_trampoline_addr uintptr
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
+func fcntl(fd int, cmd int, arg int) (n int, err error) {
+	r0, _, e1 := syscall_syscall(libc_fcntl_trampoline_addr, uintptr(fd), uintptr(cmd), uintptr(arg))
+	n = int(r0)
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+var libc_fcntl_trampoline_addr uintptr
+
+//go:cgo_import_dynamic libc_fcntl fcntl "libc.so"
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
+func fcntlPtr(fd int, cmd int, arg unsafe.Pointer) (n int, err error) {
+	r0, _, e1 := syscall_syscall(libc_fcntl_trampoline_addr, uintptr(fd), uintptr(cmd), uintptr(arg))
+	n = int(r0)
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
 func ppoll(fds *PollFd, nfds int, timeout *Timespec, sigmask *Sigset_t) (n int, err error) {
 	r0, _, e1 := syscall_syscall6(libc_ppoll_trampoline_addr, uintptr(unsafe.Pointer(fds)), uintptr(nfds), uintptr(unsafe.Pointer(timeout)), uintptr(unsafe.Pointer(sigmask)), 0, 0)
 	n = int(r0)
diff --git a/unix/zsyscall_openbsd_arm.s b/unix/zsyscall_openbsd_arm.s
index 82badae39..ac4af24f9 100644
--- a/unix/zsyscall_openbsd_arm.s
+++ b/unix/zsyscall_openbsd_arm.s
@@ -178,6 +178,11 @@ TEXT libc_sysctl_trampoline<>(SB),NOSPLIT,$0-0
 GLOBL	·libc_sysctl_trampoline_addr(SB), RODATA, $4
 DATA	·libc_sysctl_trampoline_addr(SB)/4, $libc_sysctl_trampoline<>(SB)
 
+TEXT libc_fcntl_trampoline<>(SB),NOSPLIT,$0-0
+	JMP	libc_fcntl(SB)
+GLOBL	·libc_fcntl_trampoline_addr(SB), RODATA, $4
+DATA	·libc_fcntl_trampoline_addr(SB)/4, $libc_fcntl_trampoline<>(SB)
+
 TEXT libc_ppoll_trampoline<>(SB),NOSPLIT,$0-0
 	JMP	libc_ppoll(SB)
 GLOBL	·libc_ppoll_trampoline_addr(SB), RODATA, $4
diff --git a/unix/zsyscall_openbsd_arm64.go b/unix/zsyscall_openbsd_arm64.go
index 8fb4ff36a..55df20ae9 100644
--- a/unix/zsyscall_openbsd_arm64.go
+++ b/unix/zsyscall_openbsd_arm64.go
@@ -584,6 +584,32 @@ var libc_sysctl_trampoline_addr uintptr
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
+func fcntl(fd int, cmd int, arg int) (n int, err error) {
+	r0, _, e1 := syscall_syscall(libc_fcntl_trampoline_addr, uintptr(fd), uintptr(cmd), uintptr(arg))
+	n = int(r0)
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+var libc_fcntl_trampoline_addr uintptr
+
+//go:cgo_import_dynamic libc_fcntl fcntl "libc.so"
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
+func fcntlPtr(fd int, cmd int, arg unsafe.Pointer) (n int, err error) {
+	r0, _, e1 := syscall_syscall(libc_fcntl_trampoline_addr, uintptr(fd), uintptr(cmd), uintptr(arg))
+	n = int(r0)
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
 func ppoll(fds *PollFd, nfds int, timeout *Timespec, sigmask *Sigset_t) (n int, err error) {
 	r0, _, e1 := syscall_syscall6(libc_ppoll_trampoline_addr, uintptr(unsafe.Pointer(fds)), uintptr(nfds), uintptr(unsafe.Pointer(timeout)), uintptr(unsafe.Pointer(sigmask)), 0, 0)
 	n = int(r0)
diff --git a/unix/zsyscall_openbsd_arm64.s b/unix/zsyscall_openbsd_arm64.s
index 24d7eecb9..f77d53212 100644
--- a/unix/zsyscall_openbsd_arm64.s
+++ b/unix/zsyscall_openbsd_arm64.s
@@ -178,6 +178,11 @@ TEXT libc_sysctl_trampoline<>(SB),NOSPLIT,$0-0
 GLOBL	·libc_sysctl_trampoline_addr(SB), RODATA, $8
 DATA	·libc_sysctl_trampoline_addr(SB)/8, $libc_sysctl_trampoline<>(SB)
 
+TEXT libc_fcntl_trampoline<>(SB),NOSPLIT,$0-0
+	JMP	libc_fcntl(SB)
+GLOBL	·libc_fcntl_trampoline_addr(SB), RODATA, $8
+DATA	·libc_fcntl_trampoline_addr(SB)/8, $libc_fcntl_trampoline<>(SB)
+
 TEXT libc_ppoll_trampoline<>(SB),NOSPLIT,$0-0
 	JMP	libc_ppoll(SB)
 GLOBL	·libc_ppoll_trampoline_addr(SB), RODATA, $8
diff --git a/unix/zsyscall_openbsd_mips64.go b/unix/zsyscall_openbsd_mips64.go
index f469a83ee..8c1155cbc 100644
--- a/unix/zsyscall_openbsd_mips64.go
+++ b/unix/zsyscall_openbsd_mips64.go
@@ -584,6 +584,32 @@ var libc_sysctl_trampoline_addr uintptr
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
+func fcntl(fd int, cmd int, arg int) (n int, err error) {
+	r0, _, e1 := syscall_syscall(libc_fcntl_trampoline_addr, uintptr(fd), uintptr(cmd), uintptr(arg))
+	n = int(r0)
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+var libc_fcntl_trampoline_addr uintptr
+
+//go:cgo_import_dynamic libc_fcntl fcntl "libc.so"
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
+func fcntlPtr(fd int, cmd int, arg unsafe.Pointer) (n int, err error) {
+	r0, _, e1 := syscall_syscall(libc_fcntl_trampoline_addr, uintptr(fd), uintptr(cmd), uintptr(arg))
+	n = int(r0)
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
 func ppoll(fds *PollFd, nfds int, timeout *Timespec, sigmask *Sigset_t) (n int, err error) {
 	r0, _, e1 := syscall_syscall6(libc_ppoll_trampoline_addr, uintptr(unsafe.Pointer(fds)), uintptr(nfds), uintptr(unsafe.Pointer(timeout)), uintptr(unsafe.Pointer(sigmask)), 0, 0)
 	n = int(r0)
diff --git a/unix/zsyscall_openbsd_mips64.s b/unix/zsyscall_openbsd_mips64.s
index 9a498a067..fae140b62 100644
--- a/unix/zsyscall_openbsd_mips64.s
+++ b/unix/zsyscall_openbsd_mips64.s
@@ -178,6 +178,11 @@ TEXT libc_sysctl_trampoline<>(SB),NOSPLIT,$0-0
 GLOBL	·libc_sysctl_trampoline_addr(SB), RODATA, $8
 DATA	·libc_sysctl_trampoline_addr(SB)/8, $libc_sysctl_trampoline<>(SB)
 
+TEXT libc_fcntl_trampoline<>(SB),NOSPLIT,$0-0
+	JMP	libc_fcntl(SB)
+GLOBL	·libc_fcntl_trampoline_addr(SB), RODATA, $8
+DATA	·libc_fcntl_trampoline_addr(SB)/8, $libc_fcntl_trampoline<>(SB)
+
 TEXT libc_ppoll_trampoline<>(SB),NOSPLIT,$0-0
 	JMP	libc_ppoll(SB)
 GLOBL	·libc_ppoll_trampoline_addr(SB), RODATA, $8
diff --git a/unix/zsyscall_openbsd_ppc64.go b/unix/zsyscall_openbsd_ppc64.go
index c26ca2e1a..7cc80c58d 100644
--- a/unix/zsyscall_openbsd_ppc64.go
+++ b/unix/zsyscall_openbsd_ppc64.go
@@ -584,6 +584,32 @@ var libc_sysctl_trampoline_addr uintptr
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
+func fcntl(fd int, cmd int, arg int) (n int, err error) {
+	r0, _, e1 := syscall_syscall(libc_fcntl_trampoline_addr, uintptr(fd), uintptr(cmd), uintptr(arg))
+	n = int(r0)
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+var libc_fcntl_trampoline_addr uintptr
+
+//go:cgo_import_dynamic libc_fcntl fcntl "libc.so"
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
+func fcntlPtr(fd int, cmd int, arg unsafe.Pointer) (n int, err error) {
+	r0, _, e1 := syscall_syscall(libc_fcntl_trampoline_addr, uintptr(fd), uintptr(cmd), uintptr(arg))
+	n = int(r0)
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
 func ppoll(fds *PollFd, nfds int, timeout *Timespec, sigmask *Sigset_t) (n int, err error) {
 	r0, _, e1 := syscall_syscall6(libc_ppoll_trampoline_addr, uintptr(unsafe.Pointer(fds)), uintptr(nfds), uintptr(unsafe.Pointer(timeout)), uintptr(unsafe.Pointer(sigmask)), 0, 0)
 	n = int(r0)
diff --git a/unix/zsyscall_openbsd_ppc64.s b/unix/zsyscall_openbsd_ppc64.s
index 1f224aa41..9d1e0ff06 100644
--- a/unix/zsyscall_openbsd_ppc64.s
+++ b/unix/zsyscall_openbsd_ppc64.s
@@ -213,6 +213,12 @@ TEXT libc_sysctl_trampoline<>(SB),NOSPLIT,$0-0
 GLOBL	·libc_sysctl_trampoline_addr(SB), RODATA, $8
 DATA	·libc_sysctl_trampoline_addr(SB)/8, $libc_sysctl_trampoline<>(SB)
 
+TEXT libc_fcntl_trampoline<>(SB),NOSPLIT,$0-0
+	CALL	libc_fcntl(SB)
+	RET
+GLOBL	·libc_fcntl_trampoline_addr(SB), RODATA, $8
+DATA	·libc_fcntl_trampoline_addr(SB)/8, $libc_fcntl_trampoline<>(SB)
+
 TEXT libc_ppoll_trampoline<>(SB),NOSPLIT,$0-0
 	CALL	libc_ppoll(SB)
 	RET
diff --git a/unix/zsyscall_openbsd_riscv64.go b/unix/zsyscall_openbsd_riscv64.go
index bcc920dd2..0688737f4 100644
--- a/unix/zsyscall_openbsd_riscv64.go
+++ b/unix/zsyscall_openbsd_riscv64.go
@@ -584,6 +584,32 @@ var libc_sysctl_trampoline_addr uintptr
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
+func fcntl(fd int, cmd int, arg int) (n int, err error) {
+	r0, _, e1 := syscall_syscall(libc_fcntl_trampoline_addr, uintptr(fd), uintptr(cmd), uintptr(arg))
+	n = int(r0)
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+var libc_fcntl_trampoline_addr uintptr
+
+//go:cgo_import_dynamic libc_fcntl fcntl "libc.so"
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
+func fcntlPtr(fd int, cmd int, arg unsafe.Pointer) (n int, err error) {
+	r0, _, e1 := syscall_syscall(libc_fcntl_trampoline_addr, uintptr(fd), uintptr(cmd), uintptr(arg))
+	n = int(r0)
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
 func ppoll(fds *PollFd, nfds int, timeout *Timespec, sigmask *Sigset_t) (n int, err error) {
 	r0, _, e1 := syscall_syscall6(libc_ppoll_trampoline_addr, uintptr(unsafe.Pointer(fds)), uintptr(nfds), uintptr(unsafe.Pointer(timeout)), uintptr(unsafe.Pointer(sigmask)), 0, 0)
 	n = int(r0)
diff --git a/unix/zsyscall_openbsd_riscv64.s b/unix/zsyscall_openbsd_riscv64.s
index 87a79c709..da115f9a4 100644
--- a/unix/zsyscall_openbsd_riscv64.s
+++ b/unix/zsyscall_openbsd_riscv64.s
@@ -178,6 +178,11 @@ TEXT libc_sysctl_trampoline<>(SB),NOSPLIT,$0-0
 GLOBL	·libc_sysctl_trampoline_addr(SB), RODATA, $8
 DATA	·libc_sysctl_trampoline_addr(SB)/8, $libc_sysctl_trampoline<>(SB)
 
+TEXT libc_fcntl_trampoline<>(SB),NOSPLIT,$0-0
+	JMP	libc_fcntl(SB)
+GLOBL	·libc_fcntl_trampoline_addr(SB), RODATA, $8
+DATA	·libc_fcntl_trampoline_addr(SB)/8, $libc_fcntl_trampoline<>(SB)
+
 TEXT libc_ppoll_trampoline<>(SB),NOSPLIT,$0-0
 	JMP	libc_ppoll(SB)
 GLOBL	·libc_ppoll_trampoline_addr(SB), RODATA, $8