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internal/syscall/unix: unify GetRandom implementation

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The implementation of GetRandom for Linux, FreeBSD and DragonflyBSD can
be shared.

Also remove GRND_INSECURE on DragonflyBSD as pointed out by Ian in the
review of CL 269999.

Change-Id: I5bf4c1bd51ddb2ad600652a57e0bc1bafa1cf40d
Reviewed-on: https://go-review.googlesource.com/c/go/+/299133
Trust: Tobias Klauser <tobias.klauser@gmail.com>
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This commit is contained in:
Tobias Klauser 2021-03-10 10:06:11 +01:00 committed by Tobias Klauser
parent 3a3b8164fd
commit 79e3ee52f4
4 changed files with 42 additions and 102 deletions
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40
src/internal/syscall/unix/getrandom.go Normal file
View File

@ -0,0 +1,40 @@
// Copyright 2021 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 dragonfly || freebsd || linux
// +build dragonfly freebsd linux
package unix
import (
"sync/atomic"
"syscall"
"unsafe"
)
var getrandomUnsupported int32 // atomic
// GetRandomFlag is a flag supported by the getrandom system call.
type GetRandomFlag uintptr
// GetRandom calls the getrandom system call.
func GetRandom(p []byte, flags GetRandomFlag) (n int, err error) {
if len(p) == 0 {
return 0, nil
}
if atomic.LoadInt32(&getrandomUnsupported) != 0 {
return 0, syscall.ENOSYS
}
r1, _, errno := syscall.Syscall(getrandomTrap,
uintptr(unsafe.Pointer(&p[0])),
uintptr(len(p)),
uintptr(flags))
if errno != 0 {
if errno == syscall.ENOSYS {
atomic.StoreInt32(&getrandomUnsupported, 1)
}
return 0, errno
}
return int(r1), nil
}

37
src/internal/syscall/unix/getrandom_dragonfly.go
View File

@ -4,19 +4,8 @@
package unix
import (
"sync/atomic"
"syscall"
"unsafe"
)
var randomUnsupported int32 // atomic
// DragonFlyBSD getrandom system call number.
const randomTrap uintptr = 550
// GetRandomFlag is a flag supported by the getrandom system call.
type GetRandomFlag uintptr
const getrandomTrap uintptr = 550
const (
// GRND_RANDOM is only set for portability purpose, no-op on DragonFlyBSD.
@ -24,28 +13,4 @@ const (
// GRND_NONBLOCK means return EAGAIN rather than blocking.
GRND_NONBLOCK GetRandomFlag = 0x0002
// GRND_INSECURE is an GRND_NONBLOCK alias
GRND_INSECURE GetRandomFlag = 0x0004
)
// GetRandom calls the DragonFlyBSD getrandom system call.
func GetRandom(p []byte, flags GetRandomFlag) (n int, err error) {
if len(p) == 0 {
return 0, nil
}
if atomic.LoadInt32(&randomUnsupported) != 0 {
return 0, syscall.ENOSYS
}
r1, _, errno := syscall.Syscall(randomTrap,
uintptr(unsafe.Pointer(&p[0])),
uintptr(len(p)),
uintptr(flags))
if errno != 0 {
if errno == syscall.ENOSYS {
atomic.StoreInt32(&randomUnsupported, 1)
}
return 0, errno
}
return int(r1), nil
}

34
src/internal/syscall/unix/getrandom_freebsd.go
View File

@ -4,19 +4,8 @@
package unix
import (
"sync/atomic"
"syscall"
"unsafe"
)
var randomUnsupported int32 // atomic
// FreeBSD getrandom system call number.
const randomTrap uintptr = 563
// GetRandomFlag is a flag supported by the getrandom system call.
type GetRandomFlag uintptr
const getrandomTrap uintptr = 563
const (
// GRND_NONBLOCK means return EAGAIN rather than blocking.
@ -25,24 +14,3 @@ const (
// GRND_RANDOM is only set for portability purpose, no-op on FreeBSD.
GRND_RANDOM GetRandomFlag = 0x0002
)
// GetRandom calls the FreeBSD getrandom system call.
func GetRandom(p []byte, flags GetRandomFlag) (n int, err error) {
if len(p) == 0 {
return 0, nil
}
if atomic.LoadInt32(&randomUnsupported) != 0 {
return 0, syscall.ENOSYS
}
r1, _, errno := syscall.Syscall(randomTrap,
uintptr(unsafe.Pointer(&p[0])),
uintptr(len(p)),
uintptr(flags))
if errno != 0 {
if errno == syscall.ENOSYS {
atomic.StoreInt32(&randomUnsupported, 1)
}
return 0, errno
}
return int(r1), nil
}

33
src/internal/syscall/unix/getrandom_linux.go
View File

@ -4,17 +4,6 @@
package unix
import (
"sync/atomic"
"syscall"
"unsafe"
)
var randomUnsupported int32 // atomic
// GetRandomFlag is a flag supported by the getrandom system call.
type GetRandomFlag uintptr
const (
// GRND_NONBLOCK means return EAGAIN rather than blocking.
GRND_NONBLOCK GetRandomFlag = 0x0001
@ -22,25 +11,3 @@ const (
// GRND_RANDOM means use the /dev/random pool instead of /dev/urandom.
GRND_RANDOM GetRandomFlag = 0x0002
)
// GetRandom calls the Linux getrandom system call.
// See https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=c6e9d6f38894798696f23c8084ca7edbf16ee895
func GetRandom(p []byte, flags GetRandomFlag) (n int, err error) {
if len(p) == 0 {
return 0, nil
}
if atomic.LoadInt32(&randomUnsupported) != 0 {
return 0, syscall.ENOSYS
}
r1, _, errno := syscall.Syscall(getrandomTrap,
uintptr(unsafe.Pointer(&p[0])),
uintptr(len(p)),
uintptr(flags))
if errno != 0 {
if errno == syscall.ENOSYS {
atomic.StoreInt32(&randomUnsupported, 1)
}
return 0, errno
}
return int(r1), nil
}