Use the C++11 random number generator instead of rand().

This is safer, faster, and doesn't require seeding.

src/config.cpp

@@ -557,10 +557,6 @@ Conf::Conf() : Block("")
 		}
 	}
 	Anope::CaseMapRebuild();
-
-	/* Check the user keys */
-	if (!options->Get<unsigned>("seed"))
-		Log() << "Configuration option options:seed should be set. It's for YOUR safety! Remember that!";
 }
 
 Conf::~Conf()

src/init.cpp

@@ -494,10 +494,6 @@ bool Anope::Init(int ac, char **av)
 	/* Initialize multi-language support */
 	Language::InitLanguages();
 
-	/* Initialize random number generator */
-	block = Config->GetBlock("options");
-	srand(block->Get<unsigned>("seed") ^ time(NULL));
-
 	/* load modules */
 	Log() << "Loading modules...";
 	for (int i = 0; i < Config->CountBlock("module"); ++i)

src/misc.cpp

@@ -20,7 +20,9 @@
 #include "sockets.h"
 
 #include <cerrno>
+#include <climits>
 #include <numeric>
+#include <random>
 #include <sys/stat.h>
 #include <sys/types.h>
 #ifndef _WIN32
@@ -745,10 +747,18 @@ Anope::string Anope::Random(size_t len)
 	};
 	Anope::string buf;
 	for (size_t i = 0; i < len; ++i)
-		buf.append(chars[rand() % sizeof(chars)]);
+		buf.append(chars[Anope::RandomNumber() % sizeof(chars)]);
 	return buf;
 }
 
+int Anope::RandomNumber()
+{
+	static std::random_device device;
+	static std::mt19937 engine(device());
+	static std::uniform_int_distribution<int> dist(INT_MIN, INT_MAX);
+	return dist(engine);
+}
+
 // Implementation of https://en.wikipedia.org/wiki/Levenshtein_distance
 size_t Anope::Distance(const Anope::string &s1, const Anope::string &s2)
 {

src/nickcore.cpp

@@ -224,7 +224,7 @@ uint64_t NickCore::GetId()
 		// Generate a random key for SipHash.
 		char key[16];
 		for (auto &chr : key)
-			chr = rand() % CHAR_MAX;
+			chr = Anope::RandomNumber() % CHAR_MAX;
 
 		uint64_t newid = Anope::SipHash24(secretid.c_str(), secretid.length(), key);
 		nickcoreid_map::const_iterator it = NickCoreIdList.find(newid);

src/xline.cpp

@@ -249,7 +249,7 @@ Anope::string XLineManager::GenerateUID()
 		{
 			char c;
 			do
-				c = (rand() % 75) + 48;
+				c = (Anope::RandomNumber() % 75) + 48;
 			while (!isupper(c) && !isdigit(c));
 			id += c;
 		}