Botan 2.19.5 Crypto and TLS for C&

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_OPENBSD) || defined(BOTAN_TARGET_OS_IS_FREEBSD)
11 #include <unistd.h>
12#else
13 #if defined(BOTAN_TARGET_OS_HAS_POSIX1)
14 // Allows successful compilation on macOS older than 10.12: Provides a missing typedef for `u_int`.
15 #include <sys/types.h>
16 #endif
17 #include <sys/random.h>
18#endif
19
20 namespace Botan {
21
22/**
23* Gather 256 bytes entropy from getentropy(2). Note that maximum
24* buffer size is limited to 256 bytes. On OpenBSD this does neither
25* block nor fail.
26*/
27 size_t Getentropy::poll(RandomNumberGenerator& rng)
28 {
29 secure_vector<uint8_t> buf(256);
30
31 if(::getentropy(buf.data(), buf.size()) == 0)
32 {
33 rng.add_entropy(buf.data(), buf.size());
34 return buf.size() * 8;
35 }
36
37 return 0;
38 }
39}
Botan::Getentropy::poll
size_t poll(RandomNumberGenerator &rng) override
Definition: getentropy.cpp:27
Botan::RandomNumberGenerator
Definition: rng.h:26
Botan::RandomNumberGenerator::add_entropy
virtual void add_entropy(const uint8_t input[], size_t length)=0
Botan
Definition: alg_id.cpp:13
Botan::secure_vector
std::vector< T, secure_allocator< T > > secure_vector
Definition: secmem.h:65