[glib: 1/2] gtestutils: Make test_rand_* thread-safe within a single test case

[Philip Withnall <pwithnall src gnome org>]

commit aed3c0083b38457c78faa05adb0908259a7aa92f
Author: Tomasz Miąsko <tomasz miasko gmail com>
Date:   Fri Nov 2 00:00:00 2018 +0000

    gtestutils: Make test_rand_* thread-safe within a single test case
    
    Synchronize access to random number generator `test_run_rand` with
    a lock to ensure that `g_test_rand_*` family of functions is
    thread-safe.
    
    The reseeding taking place between test case runs is intentionally left
    unsynchronized. It is an error to continue using random number generator
    after test case has already finished running. Lack of synchronization
    here will make such erroneous use readily apparent with thread
    sanitizer.

 glib/gtestutils.c | 33 +++++++++++++++++++++++++++++----
 1 file changed, 29 insertions(+), 4 deletions(-)
---
diff --git a/glib/gtestutils.c b/glib/gtestutils.c
index 119c55d92..ac85f4b2b 100644
--- a/glib/gtestutils.c
+++ b/glib/gtestutils.c
@@ -809,6 +809,7 @@ static gboolean    test_mode_fatal = TRUE;
 static gboolean    g_test_run_once = TRUE;
 static gboolean    test_run_list = FALSE;
 static gchar      *test_run_seedstr = NULL;
+G_LOCK_DEFINE_STATIC (test_run_rand);
 static GRand      *test_run_rand = NULL;
 static gchar      *test_run_name = "";
 static GSList    **test_filename_free_list;
@@ -1437,7 +1438,13 @@ test_run_seed (const gchar *rseed)
 gint32
 g_test_rand_int (void)
 {
-  return g_rand_int (test_run_rand);
+  gint32 r;
+
+  G_LOCK (test_run_rand);
+  r = g_rand_int (test_run_rand);
+  G_UNLOCK (test_run_rand);
+
+  return r;
 }
 
 /**
@@ -1456,7 +1463,13 @@ gint32
 g_test_rand_int_range (gint32          begin,
                        gint32          end)
 {
-  return g_rand_int_range (test_run_rand, begin, end);
+  gint32 r;
+
+  G_LOCK (test_run_rand);
+  r = g_rand_int_range (test_run_rand, begin, end);
+  G_UNLOCK (test_run_rand);
+
+  return r;
 }
 
 /**
@@ -1472,7 +1485,13 @@ g_test_rand_int_range (gint32          begin,
 double
 g_test_rand_double (void)
 {
-  return g_rand_double (test_run_rand);
+  double r;
+
+  G_LOCK (test_run_rand);
+  r = g_rand_double (test_run_rand);
+  G_UNLOCK (test_run_rand);
+
+  return r;
 }
 
 /**
@@ -1491,7 +1510,13 @@ double
 g_test_rand_double_range (double          range_start,
                           double          range_end)
 {
-  return g_rand_double_range (test_run_rand, range_start, range_end);
+  double r;
+
+  G_LOCK (test_run_rand);
+  r = g_rand_double_range (test_run_rand, range_start, range_end);
+  G_UNLOCK (test_run_rand);
+
+  return r;
 }
 
 /**