Botan  2.7.0
Crypto and TLS for C++11
getentropy.cpp
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1 /*
2 * System Call getentropy(2)
3 * (C) 2017 Alexander Bluhm (genua GmbH)
4 *
5 * Botan is released under the Simplified BSD License (see license.txt)
6 */
7 
8 #include <botan/internal/getentropy.h>
9 
10 #if defined(BOTAN_TARGET_OS_IS_DARWIN)
11  #include <sys/random.h>
12 #else
13  #include <unistd.h>
14 #endif
15 
16 namespace Botan {
17 
18 /**
19 * Gather 256 bytes entropy from getentropy(2). Note that maximum
20 * buffer size is limited to 256 bytes. On OpenBSD this does neither
21 * block nor fail.
22 */
24  {
25  secure_vector<uint8_t> buf(256);
26 
27  if(::getentropy(buf.data(), buf.size()) == 0)
28  {
29  rng.add_entropy(buf.data(), buf.size());
30  return buf.size() * 8;
31  }
32 
33  return 0;
34  }
35 }
virtual void add_entropy(const uint8_t input[], size_t length)=0
Definition: alg_id.cpp:13
std::vector< T, secure_allocator< T > > secure_vector
Definition: secmem.h:88
size_t poll(RandomNumberGenerator &rng) override
Definition: getentropy.cpp:23