63 lines
1.6 KiB
C++
63 lines
1.6 KiB
C++
// Copyright (c) 2012 The Chromium Authors. All rights reserved.
|
|
// Use of this source code is governed by a BSD-style license that can be
|
|
// found in the LICENSE file.
|
|
|
|
#include "base/rand_util.h"
|
|
|
|
#include <errno.h>
|
|
#include <fcntl.h>
|
|
#include <stddef.h>
|
|
#include <stdint.h>
|
|
#include <unistd.h>
|
|
|
|
#include "base/files/file_util.h"
|
|
#include "base/logging.h"
|
|
#include "base/no_destructor.h"
|
|
#include "base/posix/eintr_wrapper.h"
|
|
|
|
namespace {
|
|
|
|
// We keep the file descriptor for /dev/urandom around so we don't need to
|
|
// reopen it (which is expensive), and since we may not even be able to reopen
|
|
// it if we are later put in a sandbox. This class wraps the file descriptor so
|
|
// we can use a static-local variable to handle opening it on the first access.
|
|
class URandomFd {
|
|
public:
|
|
#if defined(OS_AIX)
|
|
// AIX has no 64-bit support for open falgs such as -
|
|
// O_CLOEXEC, O_NOFOLLOW and O_TTY_INIT
|
|
URandomFd() : fd_(HANDLE_EINTR(open("/dev/urandom", O_RDONLY))) {
|
|
DPCHECK(fd_ >= 0) << "Cannot open /dev/urandom";
|
|
}
|
|
#else
|
|
URandomFd() : fd_(HANDLE_EINTR(open("/dev/urandom", O_RDONLY | O_CLOEXEC))) {
|
|
DPCHECK(fd_ >= 0) << "Cannot open /dev/urandom";
|
|
}
|
|
#endif
|
|
|
|
~URandomFd() { close(fd_); }
|
|
|
|
int fd() const { return fd_; }
|
|
|
|
private:
|
|
const int fd_;
|
|
};
|
|
|
|
} // namespace
|
|
|
|
namespace base {
|
|
|
|
void RandBytes(void* output, size_t output_length) {
|
|
const int urandom_fd = GetUrandomFD();
|
|
const bool success =
|
|
ReadFromFD(urandom_fd, static_cast<char*>(output), output_length);
|
|
CHECK(success);
|
|
}
|
|
|
|
int GetUrandomFD() {
|
|
static NoDestructor<URandomFd> urandom_fd;
|
|
return urandom_fd->fd();
|
|
}
|
|
|
|
} // namespace base
|