63e70b67eb
Nuxi CloudABI (https://github.com/NuxiNL/cloudlibc) does not allow processes to access the global filesystem namespace. This breaks random_device, as it attempts to use /dev/{u,}random. This change adds support for arc4random(), which is present on CloudABI. In my opinion it would also make sense to use arc4random() on other operating systems, such as *BSD and Mac OS X, but I'd rather leave that to the maintainers of the respective platforms. Switching to arc4random() does change the ABI. This change also attempts to make some cleanups to the code. It adds a single #define for every random interface, instead of testing against operating systems explicitly. As discussed, also validate the token argument to be equal to "/dev/urandom" on all systems that only provide pseudo-random numbers. This should cause little to no breakage, as "/dev/urandom" is also the default argument value. Reviewed by: jfb Differential Revision: http://reviews.llvm.org/D8134 git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@231764 91177308-0d34-0410-b5e6-96231b3b80d8
153 lines
3.4 KiB
C++
153 lines
3.4 KiB
C++
//===-------------------------- random.cpp --------------------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is dual licensed under the MIT and the University of Illinois Open
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// Source Licenses. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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#if defined(_LIBCPP_USING_WIN32_RANDOM)
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// Must be defined before including stdlib.h to enable rand_s().
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#define _CRT_RAND_S
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#endif // defined(_LIBCPP_USING_WIN32_RANDOM)
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#include "random"
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#include "system_error"
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#if defined(__sun__)
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#define rename solaris_headers_are_broken
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#endif // defined(__sun__)
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#include <errno.h>
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#include <stdio.h>
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#include <stdlib.h>
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#if defined(_LIBCPP_USING_DEV_RANDOM)
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#include <fcntl.h>
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#include <unistd.h>
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#elif defined(_LIBCPP_USING_NACL_RANDOM)
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#include <nacl/nacl_random.h>
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#endif
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_LIBCPP_BEGIN_NAMESPACE_STD
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#if defined(_LIBCPP_USING_ARC4_RANDOM)
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random_device::random_device(const string& __token)
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{
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if (__token != "/dev/urandom")
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__throw_system_error(ENOENT, ("random device not supported " + __token).c_str());
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}
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random_device::~random_device()
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{
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}
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unsigned
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random_device::operator()()
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{
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return arc4random();
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}
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#elif defined(_LIBCPP_USING_DEV_RANDOM)
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random_device::random_device(const string& __token)
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: __f_(open(__token.c_str(), O_RDONLY))
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{
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if (__f_ < 0)
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__throw_system_error(errno, ("random_device failed to open " + __token).c_str());
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}
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random_device::~random_device()
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{
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close(__f_);
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}
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unsigned
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random_device::operator()()
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{
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unsigned r;
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size_t n = sizeof(r);
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char* p = reinterpret_cast<char*>(&r);
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while (n > 0)
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{
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ssize_t s = read(__f_, p, n);
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if (s == 0)
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__throw_system_error(ENODATA, "random_device got EOF");
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if (s == -1)
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{
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if (errno != EINTR)
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__throw_system_error(errno, "random_device got an unexpected error");
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continue;
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}
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n -= static_cast<size_t>(s);
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p += static_cast<size_t>(s);
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}
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return r;
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}
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#elif defined(_LIBCPP_USING_NACL_RANDOM)
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random_device::random_device(const string& __token)
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{
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if (__token != "/dev/urandom")
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__throw_system_error(ENOENT, ("random device not supported " + __token).c_str());
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int error = nacl_secure_random_init();
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if (error)
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__throw_system_error(error, ("random device failed to open " + __token).c_str());
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}
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random_device::~random_device()
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{
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}
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unsigned
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random_device::operator()()
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{
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unsigned r;
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size_t n = sizeof(r);
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size_t bytes_written;
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int error = nacl_secure_random(&r, n, &bytes_written);
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if (error != 0)
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__throw_system_error(error, "random_device failed getting bytes");
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else if (bytes_written != n)
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__throw_runtime_error("random_device failed to obtain enough bytes");
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return r;
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}
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#elif defined(_LIBCPP_USING_WIN32_RANDOM)
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random_device::random_device(const string& __token)
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{
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if (__token != "/dev/urandom")
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__throw_system_error(ENOENT, ("random device not supported " + __token).c_str());
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}
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random_device::~random_device()
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{
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}
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unsigned
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random_device::operator()()
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{
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unsigned r;
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errno_t err = rand_s(&r);
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if (err)
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__throw_system_error(err, "random_device rand_s failed.");
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return r;
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}
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#else
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#error "Random device not implemented for this architecture"
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#endif
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double
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random_device::entropy() const _NOEXCEPT
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{
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return 0;
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}
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_LIBCPP_END_NAMESPACE_STD
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