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Make random data provider code thread-safe 

This uses C++-11 thread-safe static initializers now.
This commit is contained in:
Jay Berkenbilt 2020-04-06 10:00:05 -04:00
parent 619d294e9d
commit 52749b85df
1 changed files with 54 additions and 30 deletions
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84
libqpdf/QUtil.cc
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@ -878,57 +878,81 @@ QUtil::toUTF16(unsigned long uval)
// Random data support
static RandomDataProvider* random_data_provider = 0;
#ifdef USE_INSECURE_RANDOM
static RandomDataProvider* insecure_random_data_provider =
InsecureRandomDataProvider::getInstance();
#else
static RandomDataProvider* insecure_random_data_provider = 0;
#endif
static RandomDataProvider* secure_random_data_provider =
SecureRandomDataProvider::getInstance();
static void
initialize_random_data_provider()
class RandomDataProviderProvider
{
if (random_data_provider == 0)
{
if (secure_random_data_provider)
{
random_data_provider = secure_random_data_provider;
}
else if (insecure_random_data_provider)
{
random_data_provider = insecure_random_data_provider;
}
}
public:
RandomDataProviderProvider();
void setProvider(RandomDataProvider*);
RandomDataProvider* getProvider();
private:
RandomDataProvider* default_provider;
RandomDataProvider* current_provider;
};
RandomDataProviderProvider::RandomDataProviderProvider() :
default_provider(0),
current_provider(0)
{
#ifdef USE_INSECURE_RANDOM
static RandomDataProvider* insecure_random_data_provider =
InsecureRandomDataProvider::getInstance();
#else
static RandomDataProvider* insecure_random_data_provider = 0;
#endif
static RandomDataProvider* secure_random_data_provider =
SecureRandomDataProvider::getInstance();
this->default_provider = (
secure_random_data_provider ? secure_random_data_provider
: insecure_random_data_provider ? insecure_random_data_provider
: 0);
// QUtil.hh has comments indicating that getRandomDataProvider(),
// which calls this method, never returns null.
if (random_data_provider == 0)
if (this->default_provider == 0)
{
throw std::logic_error("QPDF has no random data provider");
}
this->current_provider = default_provider;
}
RandomDataProvider*
RandomDataProviderProvider::getProvider()
{
return this->current_provider;
}
void
RandomDataProviderProvider::setProvider(RandomDataProvider* p)
{
this->current_provider = p ? p : this->default_provider;
}
static RandomDataProviderProvider*
getRandomDataProviderProvider()
{
// Thread-safe static initializer
static RandomDataProviderProvider rdpp;
return &rdpp;
}
void
QUtil::setRandomDataProvider(RandomDataProvider* p)
{
random_data_provider = p;
getRandomDataProviderProvider()->setProvider(p);
}
RandomDataProvider*
QUtil::getRandomDataProvider()
{
initialize_random_data_provider();
return random_data_provider;
return getRandomDataProviderProvider()->getProvider();
}
void
QUtil::initializeWithRandomBytes(unsigned char* data, size_t len)
{
initialize_random_data_provider();
random_data_provider->provideRandomData(data, len);
getRandomDataProvider()->provideRandomData(data, len);
}
long