unix: add CloseRange

The close_range(2) syscall is available since Linux kernel v5.9,
with additional functionality of CLOSE_RANGE_CLOEXEC since v5.11.

No tests are required since this is a bare syscall.

Change-Id: I410470e3713e2005cc7acf24d1347938fe05ef63
Reviewed-on: https://go-review.googlesource.com/c/sys/+/301409
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Trust: Emmanuel Odeke <emmanuel@orijtech.com>

unix/linux/types.go

@@ -84,6 +84,7 @@ struct termios2 {
 #include <linux/can/raw.h>
 #include <linux/capability.h>
 #include <linux/cgroupstats.h>
+#include <linux/close_range.h>
 #include <linux/cryptouser.h>
 #include <linux/devlink.h>
 #include <linux/dm-ioctl.h>
@@ -3648,3 +3649,9 @@ type (
 	HIDRawReportDescriptor C.struct_hidraw_report_descriptor
 	HIDRawDevInfo          C.struct_hidraw_devinfo
 )
+
+// close_range
+const (
+	CLOSE_RANGE_UNSHARE = C.CLOSE_RANGE_UNSHARE
+	CLOSE_RANGE_CLOEXEC = C.CLOSE_RANGE_CLOEXEC
+)

unix/syscall_linux.go

@@ -1877,6 +1877,7 @@ func Sendfile(outfd int, infd int, offset *int64, count int) (written int, err e
 //sys	ClockGettime(clockid int32, time *Timespec) (err error)
 //sys	ClockNanosleep(clockid int32, flags int, request *Timespec, remain *Timespec) (err error)
 //sys	Close(fd int) (err error)
+//sys	CloseRange(first uint, last uint, flags uint) (err error)
 //sys	CopyFileRange(rfd int, roff *int64, wfd int, woff *int64, len int, flags int) (n int, err error)
 //sys	DeleteModule(name string, flags int) (err error)
 //sys	Dup(oldfd int) (fd int, err error)

unix/zsyscall_linux.go

@@ -532,6 +532,16 @@ func Close(fd int) (err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
+func CloseRange(first uint, last uint, flags uint) (err error) {
+	_, _, e1 := Syscall(SYS_CLOSE_RANGE, uintptr(first), uintptr(last), uintptr(flags))
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
 func CopyFileRange(rfd int, roff *int64, wfd int, woff *int64, len int, flags int) (n int, err error) {
 	r0, _, e1 := Syscall6(SYS_COPY_FILE_RANGE, uintptr(rfd), uintptr(unsafe.Pointer(roff)), uintptr(wfd), uintptr(unsafe.Pointer(woff)), uintptr(len), uintptr(flags))
 	n = int(r0)

unix/ztypes_linux.go

@@ -3709,3 +3709,8 @@ type (
 		Product int16
 	}
 )
+
+const (
+	CLOSE_RANGE_UNSHARE = 0x2
+	CLOSE_RANGE_CLOEXEC = 0x4
+)