1a2f01efa6
Update the Go library to the 1.10beta1 release.
Requires a few changes to the compiler for modifications to the map
runtime code, and to handle some nowritebarrier cases in the runtime.
Reviewed-on: https://go-review.googlesource.com/86455
gotools/:
* Makefile.am (go_cmd_vet_files): New variable.
(go_cmd_buildid_files, go_cmd_test2json_files): New variables.
(s-zdefaultcc): Change from constants to functions.
(noinst_PROGRAMS): Add vet, buildid, and test2json.
(cgo$(EXEEXT)): Link against $(LIBGOTOOL).
(vet$(EXEEXT)): New target.
(buildid$(EXEEXT)): New target.
(test2json$(EXEEXT)): New target.
(install-exec-local): Install all $(noinst_PROGRAMS).
(uninstall-local): Uninstasll all $(noinst_PROGRAMS).
(check-go-tool): Depend on $(noinst_PROGRAMS). Copy down
objabi.go.
(check-runtime): Depend on $(noinst_PROGRAMS).
(check-cgo-test, check-carchive-test): Likewise.
(check-vet): New target.
(check): Depend on check-vet. Look at cmd_vet-testlog.
(.PHONY): Add check-vet.
* Makefile.in: Rebuild.
From-SVN: r256365
49 lines
1.6 KiB
Go
49 lines
1.6 KiB
Go
// 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.
|
|
|
|
package rand
|
|
|
|
import (
|
|
"internal/syscall/unix"
|
|
)
|
|
|
|
func init() {
|
|
altGetRandom = batched(getRandomLinux, maxGetRandomRead)
|
|
}
|
|
|
|
// maxGetRandomRead is the maximum number of bytes to ask for in one call to the
|
|
// getrandom() syscall. In linux at most 2^25-1 bytes will be returned per call.
|
|
// From 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.
|
|
const maxGetRandomRead = (1 << 25) - 1
|
|
|
|
// batched returns a function that calls f to populate a []byte by chunking it
|
|
// into subslices of, at most, readMax bytes.
|
|
func batched(f func([]byte) bool, readMax int) func([]byte) bool {
|
|
return func(buf []byte) bool {
|
|
for len(buf) > readMax {
|
|
if !f(buf[:readMax]) {
|
|
return false
|
|
}
|
|
buf = buf[readMax:]
|
|
}
|
|
return len(buf) == 0 || f(buf)
|
|
}
|
|
}
|
|
|
|
// If the kernel is too old (before 3.17) 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 getRandomLinux(p []byte) (ok bool) {
|
|
n, err := unix.GetRandom(p, 0)
|
|
return n == len(p) && err == nil
|
|
}
|