Botan::Unix_EntropySource Class Reference

#include <es_unix.h>

Inheritance diagram for Botan::Unix_EntropySource:

Public Member Functions
void	add_sources (const Unix_Program[], size_t)
std::string	name () const
void	poll (Entropy_Accumulator &accum)
	Unix_EntropySource (const std::vector< std::string > &path)

Detailed Description

Unix Entropy Source

Definition at line 20 of file es_unix.h.

Constructor & Destructor Documentation

Unix_EntropySource()

Botan::Unix_EntropySource::Unix_EntropySource

(

const std::vector< std::string > &

path

)

Unix_EntropySource Constructor

Definition at line 38 of file es_unix.cpp.

                                                                       :
   PATH(path)
   {
   std::vector<Unix_Program> default_sources = get_default_sources();
   add_sources(&default_sources[0], default_sources.size());
   }

References add_sources().

Member Function Documentation

add_sources()

void Botan::Unix_EntropySource::add_sources	(	const Unix_Program	srcs[],
		size_t	count )

Add sources to the list

Definition at line 48 of file es_unix.cpp.

   {
   sources.insert(sources.end(), srcs, srcs + count);
   std::sort(sources.begin(), sources.end(), Unix_Program_Cmp);
   }

Referenced by Unix_EntropySource().

name()

std::string Botan::Unix_EntropySource::name ( ) const

inlinevirtual

Returns

name identifying this entropy source

Implements Botan::EntropySource.

Definition at line 23 of file es_unix.h.

{ return "Unix Entropy Source"; }

poll()

void Botan::Unix_EntropySource::poll ( Entropy_Accumulator & accum )

virtual

Poll for entropy on a generic Unix system, first by grabbing various statistics (stat on common files, getrusage, etc), and then, if more is required, by exec'ing various programs like uname and rpcinfo and reading the output.

Implements Botan::EntropySource.

Definition at line 60 of file es_unix.cpp.

   {
   const char* stat_targets[] = {
      "/",
      "/tmp",
      "/var/tmp",
      "/usr",
      "/home",
      "/etc/passwd",
      ".",
      "..",
      0 };
 
   for(size_t i = 0; stat_targets[i]; i++)
      {
      struct stat statbuf;
      clear_mem(&statbuf, 1);
      if(::stat(stat_targets[i], &statbuf) == 0)
         accum.add(&statbuf, sizeof(statbuf), .005);
      }
 
   accum.add(::getpid(),  0);
   accum.add(::getppid(), 0);
   accum.add(::getuid(),  0);
   accum.add(::getgid(), 0);
   accum.add(::getpgrp(), 0);
 
   struct ::rusage usage;
   ::getrusage(RUSAGE_SELF, &usage);
   accum.add(usage, .005);
 
   ::getrusage(RUSAGE_CHILDREN, &usage);
   accum.add(usage, .005);
 
   const size_t MINIMAL_WORKING = 16;
 
   MemoryRegion<byte>& io_buffer = accum.get_io_buffer(DEFAULT_BUFFERSIZE);
 
   for(size_t i = 0; i != sources.size(); i++)
      {
      DataSource_Command pipe(sources[i].name_and_args, PATH);
 
      size_t got_from_src = 0;
 
      while(!pipe.end_of_data())
         {
         size_t got_this_loop = pipe.read(&io_buffer[0], io_buffer.size());
         got_from_src += got_this_loop;
 
         accum.add(&io_buffer[0], got_this_loop, .005);
         }
 
      sources[i].working = (got_from_src >= MINIMAL_WORKING) ? true : false;
 
      if(accum.polling_goal_achieved())
         break;
      }
   }

References Botan::Entropy_Accumulator::add(), Botan::clear_mem(), Botan::DataSource_Command::end_of_data(), Botan::Entropy_Accumulator::get_io_buffer(), Botan::Entropy_Accumulator::polling_goal_achieved(), Botan::DataSource_Command::read(), and Botan::MemoryRegion< T >::size().

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The documentation for this class was generated from the following files:

• src/entropy/unix_procs/es_unix.h
• src/entropy/unix_procs/es_unix.cpp
• src/entropy/unix_procs/unix_src.cpp