tools: add gentestdata

Using gentestdata you can generate a pseudo-random binary data that you
can use during testing.
This will produce the same data every time, but it looks random and the
data is neither sparse nor compressible.

core/src/tools/CMakeLists.txt

@@ -56,6 +56,10 @@ if(NOT HAVE_WIN32)
   target_link_libraries(bpluginfo bareos ${DL_LIBRARIES} CLI11::CLI11)
 endif()
 
+add_executable(gentestdata)
+target_sources(gentestdata PRIVATE gentestdata.cc)
+target_link_libraries(gentestdata PRIVATE CLI11::CLI11)
+
 set(TOOLS_BIN bsmtp bwild bregex)
 
 set(TOOLS_SBIN bscrypto bwild bregex)

core/src/tools/gentestdata.cc

@@ -0,0 +1,56 @@
+/*
+   BAREOS® - Backup Archiving REcovery Open Sourced
+
+   Copyright (C) 2023-2023 Bareos GmbH & Co. KG
+
+   This program is Free Software; you can redistribute it and/or
+   modify it under the terms of version three of the GNU Affero General Public
+   License as published by the Free Software Foundation and included
+   in the file LICENSE.
+
+   This program is distributed in the hope that it will be useful, but
+   WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+   Affero General Public License for more details.
+
+   You should have received a copy of the GNU Affero General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+   02110-1301, USA.
+*/
+#include "CLI/App.hpp"
+#include "CLI/Formatter.hpp"
+#include "CLI/Config.hpp"
+#include <random>
+#include <cstring>
+
+static void print_random(long);
+
+int main(int argc, char** argv)
+{
+  CLI::App app{"Generate a stream of pseudo-random testdata"};
+
+  long bytes{1024};
+  app.add_option("-s,--size", bytes, "Number of bytes to create");
+
+  CLI11_PARSE(app, argc, argv);
+
+  print_random(bytes);
+  return 0;
+}
+
+
+void print_random(long bytes)
+{
+  std::mt19937_64 generator{};
+  using val_type = decltype(generator());
+
+  char buf[sizeof(val_type)];
+  for (auto remaining = bytes; remaining > 0; remaining -= sizeof(val_type)) {
+    auto value = generator();
+    memcpy(buf, &value, sizeof(val_type));
+    for (auto i = 0u; i < sizeof(val_type) && remaining - i > 0; i++) {
+      std::putchar(buf[i]);
+    }
+  }
+}