From 95e4ed03bffba9e11cd11b2bd601edd38a1e75d8 Mon Sep 17 00:00:00 2001
From: Andrea Mazzoleni <amadvance@gmail.com>
Date: Sat, 27 Dec 2014 11:45:59 +0100
Subject: [PATCH] Removes rand() use from the raid module.

---
 cmdline/util.c |  5 -----
 cmdline/util.h |  2 +-
 raid/memory.c  | 10 +++++++---
 raid/memory.h  |  4 ++--
 raid/test.c    |  8 ++++----
 5 files changed, 14 insertions(+), 15 deletions(-)

diff --git a/cmdline/util.c b/cmdline/util.c
index be9ed7d3..ecee1887 100644
--- a/cmdline/util.c
+++ b/cmdline/util.c
@@ -1588,11 +1588,6 @@ void** malloc_nofail_vector_align(int nd, int n, size_t size, void** freeptr)
 	return ptr;
 }
 
-void mrand_vector(int n, size_t size, void** vv)
-{
-	raid_mrand_vector(n, size, vv);
-}
-
 void mtest_vector(int n, size_t size, void** vv)
 {
 	if (raid_mtest_vector(n, size, vv) != 0) {
diff --git a/cmdline/util.h b/cmdline/util.h
index 6eea1dc9..23552efb 100644
--- a/cmdline/util.h
+++ b/cmdline/util.h
@@ -485,7 +485,7 @@ void** malloc_nofail_vector_align(int nd, int n, size_t size, void** freeptr);
 /**
  * Fills the memory vector with random data.
  */
-void mrand_vector(int n, size_t size, void** vv);
+void mrand_vector(unsigned seed, int n, size_t size, void** vv);
 
 /**
  * Tests the memory vector for RAM problems.
diff --git a/raid/memory.c b/raid/memory.c
index bd98e01c..dcbcf086 100644
--- a/raid/memory.c
+++ b/raid/memory.c
@@ -68,15 +68,19 @@ void **raid_malloc_vector(int nd, int n, size_t size, void **freeptr)
 	return v;
 }
 
-void raid_mrand_vector(int n, size_t size, void **vv)
+void raid_mrand_vector(unsigned seed, int n, size_t size, void **vv)
 {
 	unsigned char **v = (unsigned char**)vv;
 	int i;
 	size_t j;
 
 	for (i = 0; i < n; ++i)
-		for (j = 0; j < size; ++j)
-			v[i][j] = rand();
+		for (j = 0; j < size; ++j) {
+			/* basic C99/C11 linear congruential generator */
+			seed = seed * 1103515245U + 12345U;
+
+			v[i][j] = seed >> 16;
+		}
 }
 
 int raid_mtest_vector(int n, size_t size, void **vv)
diff --git a/raid/memory.h b/raid/memory.h
index ae262caa..6deb45a8 100644
--- a/raid/memory.h
+++ b/raid/memory.h
@@ -70,9 +70,9 @@ void *raid_malloc_align(size_t size, void **freeptr);
 void **raid_malloc_vector(int nd, int n, size_t size, void **freeptr);
 
 /**
- * Fills the memory vector with random data.
+ * Fills the memory vector with pseudo-random data based on the specified seed.
  */
-void raid_mrand_vector(int n, size_t size, void **vv);
+void raid_mrand_vector(unsigned seed, int n, size_t size, void **vv);
 
 /**
  * Tests the memory vector for RAM problems.
diff --git a/raid/test.c b/raid/test.c
index 16e07501..4c196acb 100644
--- a/raid/test.c
+++ b/raid/test.c
@@ -176,8 +176,8 @@ int raid_test_rec(int mode, int nd, size_t size)
 
 	waste = v[nv - 1];
 
-	/* fill data disk with random */
-	raid_mrand_vector(nd, size, v);
+	/* fill with pseudo-random data with the arbitrary seed "1" */
+	raid_mrand_vector(1, nd, size, v);
 
 	/* setup recov functions */
 	for (i = 0; i < np; ++i) {
@@ -304,8 +304,8 @@ int raid_test_par(int mode, int nd, size_t size)
 	if (raid_mtest_vector(nv, size, v) != 0)
 		goto bail;
 
-	/* fill with random */
-	raid_mrand_vector(nv, size, v);
+	/* fill with pseudo-random data with the arbitrary seed "2" */
+	raid_mrand_vector(2, nv, size, v);
 
 	/* compute the parity */
 	raid_gen_ref(nd, np, size, v);