test_librbd_fsx: use private RNG context

It is at the core of fsx to be able to reproduce the exact op sequence
that lead to a failure.  Use reentrant glibc RNG functions to make sure
that nothing else has to chance to mess up the sequence.

Signed-off-by: Ilya Dryomov <ilya.dryomov@inktank.com>

diff --git a/src/test/librbd/fsx.c b/src/test/librbd/fsx.c
index a811a1276423698d6911b175e0b81b0311b0beb9..c684383d039aa2c733fa97538151a2de014bb8e3 100644 (file)
--- a/src/test/librbd/fsx.c
+++ b/src/test/librbd/fsx.c
@@ -118,7 +118,6 @@ char        dirpath[1024];
 
 off_t          file_size = 0;
 off_t          biggest = 0;
-char           state[256];
 unsigned long  testcalls = 0;          /* calls to function "test" */
 
 unsigned long  simulatedopcount = 0;   /* -b flag */
@@ -226,9 +225,31 @@ simple_err(const char *msg, int err)
     fprintf(stderr, "%s: %s\n", msg, strerror(-err));
 }
 
+/*
+ * random
+ */
+
+#define RND_STATE_LEN  256
+char   rnd_state[RND_STATE_LEN];
+struct random_data rnd_data;
+
+int32_t
+get_random(void)
+{
+       int32_t val;
+
+       if (random_r(&rnd_data, &val) < 0) {
+               prterr("random_r");
+               exit(1);
+       }
+
+       return val;
+}
+
 /*
  * rbd
  */
+
 struct rbd_ctx {
        const char *name;       /* image name */
        rbd_image_t image;      /* image handle */
@@ -1306,9 +1327,9 @@ do_clone()
        int order = 0, stripe_unit = 0, stripe_count = 0;
 
        if (randomize_striping) {
-               order = 18 + rand() % 8;
-               stripe_unit = 1ull << (order - 1 - (rand() % 8));
-               stripe_count = 2 + rand() % 14;
+               order = 18 + get_random() % 8;
+               stripe_unit = 1ull << (order - 1 - (get_random() % 8));
+               stripe_count = 2 + get_random() % 14;
        }
 
        log4(OP_CLONE, 0, 0, 0);
@@ -1508,7 +1529,7 @@ test(void)
 {
        unsigned long   offset;
        unsigned long   size = maxoplen;
-       unsigned long   rv = random();
+       unsigned long   rv = get_random();
        unsigned long   op;
 
        if (simulatedopcount > 0 && testcalls == simulatedopcount)
@@ -1525,9 +1546,9 @@ test(void)
        if (!quiet && testcalls < simulatedopcount && testcalls % 100000 == 0)
                prt("%lu...\n", testcalls);
 
-       offset = random();
+       offset = get_random();
        if (randomoplen)
-               size = random() % (maxoplen + 1);
+               size = get_random() % (maxoplen + 1);
 
        /* calculate appropriate op to run */
        if (lite)
@@ -1557,7 +1578,7 @@ test(void)
                }
                break;
        case OP_CLONE:
-               if (!clone_calls || random() % 100 > 5 || file_size == 0) {
+               if (!clone_calls || get_random() % 100 > 5 || file_size == 0) {
                        log4(OP_SKIPPED, OP_CLONE, 0, 0);
                        goto out;
                }
@@ -1587,7 +1608,7 @@ test(void)
 
        case OP_TRUNCATE:
                if (!style)
-                       size = random() % maxfilelen;
+                       size = get_random() % maxfilelen;
                dotruncate(size);
                break;
 
@@ -2027,8 +2048,14 @@ main(int argc, char **argv)
        signal(SIGUSR1, cleanup);
        signal(SIGUSR2, cleanup);
 
-       initstate(seed, state, 256);
-       setstate(state);
+       if (initstate_r(seed, rnd_state, RND_STATE_LEN, &rnd_data) < 0) {
+               prterr("initstate_r");
+               exit(1);
+       }
+       if (setstate_r(rnd_state, &rnd_data) < 0) {
+               prterr("setstate_r");
+               exit(1);
+       }
 
        ret = create_image();
        if (ret < 0) {
@@ -2064,7 +2091,7 @@ main(int argc, char **argv)
 
        original_buf = (char *) malloc(maxfilelen);
        for (i = 0; i < (int)maxfilelen; i++)
-               original_buf[i] = random() % 256;
+               original_buf[i] = get_random() % 256;
 
        ret = posix_memalign((void **)&good_buf,
                             MAX(writebdy, (int)sizeof(void *)), maxfilelen);