lok: reseed comphelper's random number generator on fork.

Also avoid std::random_device it doesn't work in a COOL
kit process.

Change-Id: Ie2d063611a73e734afd92d6fd779f34a2f316230
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/167070
Tested-by: Jenkins
Reviewed-by: Michael Meeks <michael.meeks@collabora.com>

3 files changed, 24 insertions, 16 deletions

diff --git a/comphelper/source/misc/random.cxx b/comphelper/source/misc/random.cxx
index 96d466641dfb..058eb99813eb 100644
--- a/comphelper/source/misc/random.cxx
+++ b/comphelper/source/misc/random.cxx
@@ -16,6 +16,7 @@
 #include <time.h>
 #include <mutex>
 #include <random>
+#include <rtl/random.h>
 #include <stdexcept>
 #if defined HAVE_VALGRIND_HEADERS
 #include <valgrind/memcheck.h>
@@ -40,7 +41,9 @@ struct RandomNumberGenerator
 {
     std::mutex mutex;
     STD_RNG_ALGO global_rng;
-    RandomNumberGenerator()
+    RandomNumberGenerator() { reseed(); }
+
+    void reseed()
     {
         // make RR easier to use, breaks easily without the RNG being repeatable
         bool bRepeatable = (getenv("SAL_RAND_REPEATABLE") != nullptr) || (getenv("RR") != nullptr);
@@ -56,21 +59,18 @@ struct RandomNumberGenerator
             return;
         }
 
-        try
-        {
-            std::random_device rd;
-            // initialises the state of the global random number generator
-            // should only be called once.
-            // (note, a few std::variate_generator<> (like normal) have their
-            // own state which would need a reset as well to guarantee identical
-            // sequence of numbers, e.g. via myrand.distribution().reset())
-            global_rng.seed(rd() ^ time(nullptr));
-        }
-        catch (std::runtime_error& e)
-        {
-            SAL_WARN("comphelper", "Using std::random_device failed: " << e.what());
-            global_rng.seed(time(nullptr));
-        }
+        size_t seed = 0;
+        rtlRandomPool aRandomPool = rtl_random_createPool();
+        if (rtl_random_getBytes(aRandomPool, &seed, sizeof(seed)) != rtl_Random_E_None)
+            seed = 0;
+        rtl_random_destroyPool(aRandomPool);
+
+        // initialises the state of the global random number generator
+        // should only be called once.
+        // (note, a few std::variate_generator<> (like normal) have their
+        // own state which would need a reset as well to guarantee identical
+        // sequence of numbers, e.g. via myrand.distribution().reset())
+        global_rng.seed(seed ^ time(nullptr));
     }
 };
 
@@ -81,6 +81,8 @@ RandomNumberGenerator& GetTheRandomNumberGenerator()
 }
 }
 
+void reseed() { GetTheRandomNumberGenerator().reseed(); }
+
 // uniform ints [a,b] distribution
 int uniform_int_distribution(int a, int b)
 {
diff --git a/desktop/source/lib/init.cxx b/desktop/source/lib/init.cxx
index ce1ba38334f6..28ba524ad0eb 100644
--- a/desktop/source/lib/init.cxx
+++ b/desktop/source/lib/init.cxx
@@ -76,6 +76,7 @@
 #include <rtl/uri.hxx>
 #include <linguistic/misc.hxx>
 #include <cppuhelper/bootstrap.hxx>
+#include <comphelper/random.hxx>
 #include <comphelper/base64.hxx>
 #include <comphelper/dispatchcommand.hxx>
 #include <comphelper/lok.hxx>
@@ -7969,7 +7970,10 @@ static int lo_initialize(LibreOfficeKit* pThis, const char* pAppPath, const char
         }
         rtl::Bootstrap::set(u"UserInstallation"_ustr, url);
         if (eStage == SECOND_INIT)
+        {
+            comphelper::rng::reseed();
             utl::Bootstrap::reloadData();
+        }
     }
 
     OUString aAppPath;
diff --git a/include/comphelper/random.hxx b/include/comphelper/random.hxx
index 345d57c7158d..1fe4dc5fdf58 100644
--- a/include/comphelper/random.hxx
+++ b/include/comphelper/random.hxx
@@ -17,6 +17,8 @@ namespace comphelper::rng
 // These functions obey the SAL_RAND_REPEATABLE environment
 // variable: If it is set, use a fixed seed.
 
+COMPHELPER_DLLPUBLIC void reseed();
+
 // note that uniform_int_distribution is inclusive of b, i.e. [a,b] while
 // uniform_real_distribution is exclusive of b, i.e. [a,b), std::nextafter may be your friend there