[svn-r12019] Purpose:

Bug fix/Feature

Description:
Modify the library to use rand_r, when available, instead of srand.  If
rand_r is not available, it will try to use srandom/random, and then finally
fall back to srand/rand.

Solution:
A couple places in the library use the srand() function to seed the random
number generator.  This can cause problems on certain platforms and could theoretically
cause problems for users who expect a certain sequence of random numbers following their
own call to srand().

Most platforms have an implementation of rand_r, which is identical to rand, except that
it allows for explicit storage of the seed value.  The configure script will now check
for the existence of rand_r to facilitate its use in the library.

Two new functions are added, to replace the macros HDsrand/HDrand.  These functions are HDrand and
HDsrand.  HDrand will call rand_r, if available, or random(), if available, and fall back to rand() if neither
of those is available.  HDsrand will store the seed value locally, if rand_r is available.  Otherwise, it will call
srandom if available, and fall back to srand otherwise.


Platforms tested:
heping, mir.  Really need to test on Red Storm, since that platform motivated this fix, but the machine
is currently not available.

Misc. update:

configure

@@ -46663,7 +46663,8 @@ done
 
 
 
-for ac_func in random srandom
+
+for ac_func in rand_r random srandom
 do
 as_ac_var=`echo "ac_cv_func_$ac_func" | $as_tr_sh`
 echo "$as_me:$LINENO: checking for $ac_func" >&5

configure.in

@@ -1606,7 +1606,7 @@ dnl
 AC_CHECK_FUNCS(alarm fork frexpf frexpl gethostname getpwuid getrusage)
 AC_CHECK_FUNCS(BSDgettimeofday longjmp setsysinfo sigaction)
 AC_CHECK_FUNCS(signal snprintf vasprintf strdup system waitpid)
-AC_CHECK_FUNCS(random srandom)
+AC_CHECK_FUNCS(rand_r random srandom)
 AC_CHECK_FUNCS(tmpfile)
 
 dnl Check for vsnprintf() separately, so we can detect situations where it

src/H5.c

@@ -3114,3 +3114,48 @@ H5_trace (const double *returning, const char *func, const char *type, ...)
     HDfflush (out);
     return event_time.etime;
 }
+
+/*-------------------------------------------------------------------------
+ * Function:	HDrand/HDsrand
+ *
+ * Purpose:	Wrapper function for rand.  If rand_r exists on this system,
+ * 		use it.  Otherwise, just call random() or rand().
+ *
+ * 		Wrapper function for srand.  If rand_r is available, it will keep
+ * 		track of the seed locally instead of using srand() which modifies
+ * 		global state and can break other programs.  Otherwise, just call
+ * 		srandom() or srand().
+ *
+ * Return:	Success:	Random number from 0 to RAND_MAX
+ *
+ *		Failure:	Cannot fail.
+ *
+ * Programmer:	Leon Arber
+ *              March 6, 2006.
+ *
+ * Modifications:
+ *-------------------------------------------------------------------------
+ */
+static unsigned int g_seed = 42;
+
+int HDrand(void)
+{
+#ifdef H5_HAVE_RAND_R
+    return rand_r(&g_seed);
+#elif H5_HAVE_RANDOM
+    return random();
+#else
+    return rand();
+#endif
+}
+
+void HDsrand(unsigned int seed)
+{
+#ifdef H5_HAVE_RAND_R
+    g_seed = seed; 
+#elif H5_HAVE_RANDOM
+    return srandom(seed);
+#else
+    return srand(seed);
+#endif
+}

src/H5SL.c

@@ -203,7 +203,7 @@ H5FL_BARR_DEFINE_STATIC(H5SL_node_t,H5SL_node_ptr_t,H5SL_LEVEL_MAX);
  EXAMPLES
  REVISION LOG
 --------------------------------------------------------------------------*/
-static herr_t
+    static herr_t
 H5SL_init_interface(void)
 {
     time_t curr_time;   /* Current time, for seeding random number generator */
@@ -214,12 +214,14 @@ H5SL_init_interface(void)
  * This causes Lustre on Redstorm to hang with following errors. (Lustre
  * has fix it, but not deployed at RedStorm yet. 
  * (client.c:568:ptlrpc_check_status()) @@@ type == PTL_RPC_MSG_ERR, err == -114 req@0x57a9660 x1/t0 o38->mds_l2@MDS_PEER_UUID:12 lens 240/272 ref 1 fl Rpc:R/100000/0 rc 0/-114
- */
+ *
-#ifndef RED_STORM 
+ * 3/6/06.  LA:
-    /* Create randomized set of numbers */
+ * Shouldn't need patch anymore because HDsrand will use rand_r on Red Storm instead of srand.
+ */ 
+
+/* Create randomized set of numbers */
     curr_time=HDtime(NULL);
     HDsrand((unsigned)curr_time);
-#endif
 
     FUNC_LEAVE_NOAPI(SUCCEED)
 } /* end H5SL_init_interface() */

src/H5config.h.in

@@ -208,6 +208,9 @@
 /* Define to 1 if you have the `random' function. */
 #undef HAVE_RANDOM
 
+/* Define to 1 if you have the `rand_r' function. */
+#undef HAVE_RAND_R
+
 /* Define to 1 if you have the <setjmp.h> header file. */
 #undef HAVE_SETJMP_H
 

src/H5private.h

@@ -772,12 +772,8 @@ typedef off_t                   h5_stat_size_t;
 #define HDputs(S)		puts(S)
 #define HDqsort(M,N,Z,F)	qsort(M,N,Z,F)
 #define HDraise(N)		raise(N)
-#define HDrand()		rand()
+#define HDrandom()		HDrand()
-#ifdef  H5_HAVE_RANDOM
+#define HDsrandom(S)		HDsrand(S)
-#define HDrandom()              random()
-#else
-#define HDrandom()		rand()
-#endif
 #define HDread(F,M,Z)		read(F,M,Z)
 #define HDreaddir(D)		readdir(D)
 #define HDrealloc(M,Z)		realloc(M,Z)
@@ -817,12 +813,6 @@ typedef off_t                   h5_stat_size_t;
 #endif
 /* sprintf() variable arguments */
 #define HDsqrt(X)		sqrt(X)
-#define HDsrand(N)		srand(N)
-#ifdef H5_HAVE_SRANDOM
-#define HDsrandom(N)		srandom(N)
-#else
-#define HDsrandom(N)            srand(N)
-#endif
 /* sscanf() variable arguments */
 
 

test/tselect.c

@@ -3811,7 +3811,7 @@ test_select_hyper_union_random_5d(hid_t read_plist)
 #else /* QAK */
         seed=987909620;
 #endif /* QAK */
-        srand(seed);
+        HDsrand(seed);
 
 #ifdef QAK
 printf("test_num=%d, seed=%u\n",test_num,seed);