Botan
1.11.15
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#include <proc_walk.h>
Public Member Functions | |
std::string | name () const |
void | poll (Entropy_Accumulator &accum) |
ProcWalking_EntropySource (const std::string &root_dir) | |
Static Public Member Functions | |
static void | poll_available_sources (class Entropy_Accumulator &accum) |
File Tree Walking Entropy Source
Definition at line 26 of file proc_walk.h.
Botan::ProcWalking_EntropySource::ProcWalking_EntropySource | ( | const std::string & | root_dir | ) | [inline] |
Definition at line 33 of file proc_walk.h.
:
m_path(root_dir), m_dir(nullptr) {}
std::string Botan::ProcWalking_EntropySource::name | ( | ) | const [inline, virtual] |
Implements Botan::EntropySource.
Definition at line 29 of file proc_walk.h.
{ return "Proc Walker"; }
void Botan::ProcWalking_EntropySource::poll | ( | Entropy_Accumulator & | accum | ) | [virtual] |
Perform an entropy gathering poll
accum | is an accumulator object that will be given entropy |
Implements Botan::EntropySource.
Definition at line 113 of file proc_walk.cpp.
References Botan::Entropy_Accumulator::add(), Botan::Entropy_Accumulator::get_io_buffer(), m_mutex, and Botan::Entropy_Accumulator::polling_goal_achieved().
{ const size_t MAX_FILES_READ_PER_POLL = 2048; const double ENTROPY_ESTIMATE = 1.0 / (8*1024); std::lock_guard<std::mutex> lock(m_mutex); if(!m_dir) m_dir.reset(new Directory_Walker(m_path)); secure_vector<byte>& io_buffer = accum.get_io_buffer(4096); for(size_t i = 0; i != MAX_FILES_READ_PER_POLL; ++i) { int fd = m_dir->next_fd(); // If we've exhaused this walk of the directory, halt the poll if(fd == -1) { m_dir.reset(); break; } ssize_t got = ::read(fd, &io_buffer[0], io_buffer.size()); ::close(fd); if(got > 0) accum.add(&io_buffer[0], got, ENTROPY_ESTIMATE); if(accum.polling_goal_achieved()) break; } }
void Botan::EntropySource::poll_available_sources | ( | class Entropy_Accumulator & | accum | ) | [static, inherited] |
Definition at line 108 of file entropy_srcs.cpp.
References Botan::Entropy_Accumulator::polling_goal_achieved().
Referenced by Botan::HMAC_RNG::reseed().
{ static std::vector<std::unique_ptr<EntropySource>> g_sources(get_default_entropy_sources()); if(g_sources.empty()) throw std::runtime_error("No entropy sources enabled at build time, poll failed"); size_t poll_attempt = 0; while(!accum.polling_goal_achieved() && poll_attempt < 16) { const size_t src_idx = poll_attempt % g_sources.size(); g_sources[src_idx]->poll(accum); ++poll_attempt; } }