unix: use vDSO for getrandom() on linux
With CL 614835 adding support in the runtime for calling into the
getrandom() vDSO function, wire up x/sys/unix's Getrandom() function to
it, so that callers can benefit from the increased speed and shared
vDSO state with the runtime.
Updates golang/go#69577.
Change-Id: I17734409982c51bb984a6337f4ffa8f60414ebee
Reviewed-on: https://go-review.googlesource.com/c/sys/+/615335
Reviewed-by: Michael Pratt <mpratt@google.com>
Reviewed-by: David Chase <drchase@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
diff --git a/unix/syscall_linux.go b/unix/syscall_linux.go
index c5bb17a..f08abd4 100644
--- a/unix/syscall_linux.go
+++ b/unix/syscall_linux.go
@@ -2001,7 +2001,26 @@
//sysnb Getpid() (pid int)
//sysnb Getppid() (ppid int)
//sys Getpriority(which int, who int) (prio int, err error)
-//sys Getrandom(buf []byte, flags int) (n int, err error)
+
+func Getrandom(buf []byte, flags int) (n int, err error) {
+ vdsoRet, supported := vgetrandom(buf, uint32(flags))
+ if supported {
+ if vdsoRet < 0 {
+ return 0, errnoErr(syscall.Errno(-vdsoRet))
+ }
+ return vdsoRet, nil
+ }
+ var p *byte
+ if len(buf) > 0 {
+ p = &buf[0]
+ }
+ r, _, e := Syscall(SYS_GETRANDOM, uintptr(unsafe.Pointer(p)), uintptr(len(buf)), uintptr(flags))
+ if e != 0 {
+ return 0, errnoErr(e)
+ }
+ return int(r), nil
+}
+
//sysnb Getrusage(who int, rusage *Rusage) (err error)
//sysnb Getsid(pid int) (sid int, err error)
//sysnb Gettid() (tid int)
diff --git a/unix/vgetrandom_linux.go b/unix/vgetrandom_linux.go
new file mode 100644
index 0000000..47cce9b
--- /dev/null
+++ b/unix/vgetrandom_linux.go
@@ -0,0 +1,12 @@
+// Copyright 2024 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 linux && go1.24
+
+package unix
+
+import _ "unsafe"
+
+//go:linkname vgetrandom runtime.vgetrandom
+func vgetrandom(p []byte, flags uint32) (ret int, supported bool)
diff --git a/unix/vgetrandom_unsupported.go b/unix/vgetrandom_unsupported.go
new file mode 100644
index 0000000..297e97b
--- /dev/null
+++ b/unix/vgetrandom_unsupported.go
@@ -0,0 +1,11 @@
+// Copyright 2024 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 !linux || !go1.24
+
+package unix
+
+func vgetrandom(p []byte, flags uint32) (ret int, supported bool) {
+ return -1, false
+}
diff --git a/unix/zsyscall_linux.go b/unix/zsyscall_linux.go
index 1bc1a5a..af30da5 100644
--- a/unix/zsyscall_linux.go
+++ b/unix/zsyscall_linux.go
@@ -971,23 +971,6 @@
// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
-func Getrandom(buf []byte, flags int) (n int, err error) {
- var _p0 unsafe.Pointer
- if len(buf) > 0 {
- _p0 = unsafe.Pointer(&buf[0])
- } else {
- _p0 = unsafe.Pointer(&_zero)
- }
- r0, _, e1 := Syscall(SYS_GETRANDOM, uintptr(_p0), uintptr(len(buf)), uintptr(flags))
- n = int(r0)
- if e1 != 0 {
- err = errnoErr(e1)
- }
- return
-}
-
-// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
-
func Getrusage(who int, rusage *Rusage) (err error) {
_, _, e1 := RawSyscall(SYS_GETRUSAGE, uintptr(who), uintptr(unsafe.Pointer(rusage)), 0)
if e1 != 0 {
