malloc: avoid global locks in tst-aligned_alloc-lib.c

Make sure the DSO used by aligned_alloc/calloc/malloc tests does not get
a global lock on multithreaded tests.
Reviewed-by: Arjun Shankar <arjun@redhat.com>

1 files changed, 20 insertions, 19 deletions

diff --git a/malloc/tst-aligned_alloc-lib.c b/malloc/tst-aligned_alloc-lib.c
index 0205df5..9ef1f83 100644
--- a/malloc/tst-aligned_alloc-lib.c
+++ b/malloc/tst-aligned_alloc-lib.c
@@ -17,37 +17,38 @@
    License along with the GNU C Library; see the file COPYING.LIB.  If
    not, see <https://www.gnu.org/licenses/>.  */
 
-#include <array_length.h>
 #include <libc-symbols.h>
 #include <stdlib.h>
+#include <time.h>
 
 extern void *__libc_malloc (size_t size);
 extern void *__libc_calloc (size_t n, size_t size);
 
+__thread unsigned int seed = 0;
+
 int aligned_alloc_count = 0;
 int libc_malloc_count = 0;
 int libc_calloc_count = 0;
 
-/* Get a random alignment value.  Biased towards the smaller values.  Must be
-   a power of 2. */
-static size_t get_random_alignment (void)
-{
-  size_t aligns[] = {
-    1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192, 16384
-  };
-
-  return aligns[random () % array_length (aligns)];
-}
-
-static void *get_random_alloc (size_t size)
+static void *
+get_random_alloc (size_t size)
 {
   void *retval;
   size_t align;
+  struct timespec tp;
+
+  if (seed == 0)
+    {
+      clock_gettime (CLOCK_REALTIME, &tp);
+      seed = tp.tv_nsec;
+    }
 
-  switch (random() % 3)
-  {
+  switch (rand_r (&seed) % 3)
+    {
     case 1:
-      align = get_random_alignment ();
+      /* Get a random alignment value.  Biased towards the smaller
+       * values up to 16384. Must be a power of 2. */
+      align = 1 << rand_r (&seed) % 15;
       retval = aligned_alloc (align, size);
       aligned_alloc_count++;
       break;
@@ -59,13 +60,13 @@ static void *get_random_alloc (size_t size)
       retval = __libc_malloc (size);
       libc_malloc_count++;
       break;
-  }
+    }
 
   return retval;
 }
 
-
-void * __random_malloc (size_t size)
+void *
+__random_malloc (size_t size)
 {
   return get_random_alloc (size);
 }