From 43a123c1ae6613b3efeed291fa552ecd909d3acf Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Tue, 16 Apr 2024 21:23:18 +0200 Subject: Adding upstream version 1.20.14. Signed-off-by: Daniel Baumann --- src/crypto/rand/rand_getrandom.go | 48 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 48 insertions(+) create mode 100644 src/crypto/rand/rand_getrandom.go (limited to 'src/crypto/rand/rand_getrandom.go') diff --git a/src/crypto/rand/rand_getrandom.go b/src/crypto/rand/rand_getrandom.go new file mode 100644 index 0000000..478aa5c --- /dev/null +++ b/src/crypto/rand/rand_getrandom.go @@ -0,0 +1,48 @@ +// Copyright 2014 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 || freebsd || dragonfly || solaris + +package rand + +import ( + "internal/syscall/unix" + "runtime" + "syscall" +) + +func init() { + var maxGetRandomRead int + switch runtime.GOOS { + case "linux", "android": + // Per the manpage: + // When reading from the urandom source, a maximum of 33554431 bytes + // is returned by a single call to getrandom() on systems where int + // has a size of 32 bits. + maxGetRandomRead = (1 << 25) - 1 + case "freebsd", "dragonfly", "solaris", "illumos": + maxGetRandomRead = 1 << 8 + default: + panic("no maximum specified for GetRandom") + } + altGetRandom = batched(getRandom, maxGetRandomRead) +} + +// If the kernel is too old to support the getrandom syscall(), +// unix.GetRandom will immediately return ENOSYS and we will then fall back to +// reading from /dev/urandom in rand_unix.go. unix.GetRandom caches the ENOSYS +// result so we only suffer the syscall overhead once in this case. +// If the kernel supports the getrandom() syscall, unix.GetRandom will block +// until the kernel has sufficient randomness (as we don't use GRND_NONBLOCK). +// In this case, unix.GetRandom will not return an error. +func getRandom(p []byte) error { + n, err := unix.GetRandom(p, 0) + if err != nil { + return err + } + if n != len(p) { + return syscall.EIO + } + return nil +} -- cgit v1.2.3