4d9f97b40b
Make sure we appropriately retry calls to read if the return result is less than what we asked for. Additionally, check and handle IO errors: EINTR results in the read operation getting restarted; other errors turn into exceptions. git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@210061 91177308-0d34-0410-b5e6-96231b3b80d8
92 lines
1.9 KiB
C++
92 lines
1.9 KiB
C++
//===-------------------------- random.cpp --------------------------------===//
|
|
//
|
|
// The LLVM Compiler Infrastructure
|
|
//
|
|
// This file is dual licensed under the MIT and the University of Illinois Open
|
|
// Source Licenses. See LICENSE.TXT for details.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#if defined(_WIN32)
|
|
// Must be defined before including stdlib.h to enable rand_s().
|
|
#define _CRT_RAND_S
|
|
#include <stdio.h>
|
|
#endif
|
|
|
|
#include "random"
|
|
#include "system_error"
|
|
|
|
#ifdef __sun__
|
|
#define rename solaris_headers_are_broken
|
|
#endif
|
|
#if !defined(_WIN32)
|
|
#include <fcntl.h>
|
|
#include <unistd.h>
|
|
#endif // defined(_WIN32)
|
|
#include <errno.h>
|
|
|
|
_LIBCPP_BEGIN_NAMESPACE_STD
|
|
|
|
#if defined(_WIN32)
|
|
random_device::random_device(const string&)
|
|
{
|
|
}
|
|
|
|
random_device::~random_device()
|
|
{
|
|
}
|
|
|
|
unsigned
|
|
random_device::operator()()
|
|
{
|
|
unsigned r;
|
|
errno_t err = rand_s(&r);
|
|
if (err)
|
|
__throw_system_error(err, "random_device rand_s failed.");
|
|
return r;
|
|
}
|
|
#else
|
|
random_device::random_device(const string& __token)
|
|
: __f_(open(__token.c_str(), O_RDONLY))
|
|
{
|
|
if (__f_ < 0)
|
|
__throw_system_error(errno, ("random_device failed to open " + __token).c_str());
|
|
}
|
|
|
|
random_device::~random_device()
|
|
{
|
|
close(__f_);
|
|
}
|
|
|
|
unsigned
|
|
random_device::operator()()
|
|
{
|
|
unsigned r;
|
|
size_t n = sizeof(r);
|
|
char* p = reinterpret_cast<char*>(&r);
|
|
while (n > 0)
|
|
{
|
|
ssize_t s = read(__f_, p, n);
|
|
if (s == 0)
|
|
__throw_system_error(ENODATA, "random_device got EOF");
|
|
if (s == -1)
|
|
{
|
|
if (errno != EINTR)
|
|
__throw_system_error(errno, "random_device got an unexpected error");
|
|
continue;
|
|
}
|
|
n -= static_cast<size_t>(s);
|
|
p += static_cast<size_t>(s);
|
|
}
|
|
return r;
|
|
}
|
|
#endif // defined(_WIN32)
|
|
|
|
double
|
|
random_device::entropy() const _NOEXCEPT
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
_LIBCPP_END_NAMESPACE_STD
|