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/*
* Unix EntropySource
* (C) 1999-2009 Jack Lloyd
*
* Distributed under the terms of the Botan license
*/
#include <botan/internal/es_unix.h>
#include <botan/internal/unix_cmd.h>
#include <botan/parsing.h>
#include <algorithm>
#include <sys/time.h>
#include <sys/stat.h>
#include <sys/resource.h>
#include <unistd.h>
namespace Botan {
namespace {
/**
* Sort ordering by priority
*/
bool Unix_Program_Cmp(const Unix_Program& a, const Unix_Program& b)
{
if(a.priority == b.priority)
return (a.name_and_args < b.name_and_args);
return (a.priority < b.priority);
}
}
/**
* Unix_EntropySource Constructor
*/
Unix_EntropySource::Unix_EntropySource(const std::vector<std::string>& path) :
PATH(path)
{
std::vector<Unix_Program> default_sources = get_default_sources();
add_sources(&default_sources[0], default_sources.size());
}
/**
* Add sources to the list
*/
void Unix_EntropySource::add_sources(const Unix_Program srcs[], size_t count)
{
sources.insert(sources.end(), srcs, srcs + count);
std::sort(sources.begin(), sources.end(), Unix_Program_Cmp);
}
/**
* 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.
*/
void Unix_EntropySource::poll(Entropy_Accumulator& accum)
{
const char* stat_targets[] = {
"/",
"/tmp",
"/var/tmp",
"/usr",
"/home",
"/etc/passwd",
".",
"..",
nullptr };
for(size_t i = 0; stat_targets[i]; i++)
{
struct stat statbuf;
clear_mem(&statbuf, 1);
::stat(stat_targets[i], &statbuf);
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;
secure_vector<byte>& io_buffer = accum.get_io_buffer(4*1024);
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;
}
}
}
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