From 07c49f832e00d78c0e3cd67976e335aed005a9a6 Mon Sep 17 00:00:00 2001
From: Christoffer Lerno <christoffer@aegik.com>
Date: Tue, 24 Sep 2024 18:38:11 +0200
Subject: [PATCH] Safer seed of rand with WASM.

---
 lib/std/math/random/math.seeder.c3 | 15 ++++++++++++++-
 releasenotes.md                    |  1 +
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/lib/std/math/random/math.seeder.c3 b/lib/std/math/random/math.seeder.c3
index 562e32c62..acd5ffc1a 100644
--- a/lib/std/math/random/math.seeder.c3
+++ b/lib/std/math/random/math.seeder.c3
@@ -72,8 +72,9 @@ macro uint hash(value) @local
 	return fnv32a::encode(&&bitcast(value, char[$sizeof(value)]));
 }
 
-fn char[8 * 4] entropy()
+fn char[8 * 4] entropy() @if(!env::WASM_NOLIBC)
 {
+
 	void* addr = malloc(1);
 	free(addr);
 	static uint random_int;
@@ -89,4 +90,16 @@ fn char[8 * 4] entropy()
 		hash(allocator::heap())
     };
     return bitcast(entropy_data, char[8 * 4]);
+}
+
+fn char[8 * 4] entropy() @if(env::WASM_NOLIBC)
+{
+	static uint random_int;
+	random_int += 0xedf19156;
+	uint[8] entropy_data = {
+		hash($$TIME),
+		hash(&entropy),
+		random_int,
+    };
+    return bitcast(entropy_data, char[8 * 4]);
 }
\ No newline at end of file
diff --git a/releasenotes.md b/releasenotes.md
index 7a48a16bf..d6a89eb37 100644
--- a/releasenotes.md
+++ b/releasenotes.md
@@ -56,6 +56,7 @@
 - Fix bug when passing a type as a compile time value.
 - Fix bug due to enum associated values not being checked for liveness.
 - Regression when compile time accessing a union field not last assigned to.
+- Safer seed of rand() for WASM without libc.
 
 ### Stdlib changes
 - Additional init functions for hashmap.