From 633a00b9b8d23a716401ac076b40901386348566 Mon Sep 17 00:00:00 2001
From: e2dk4r <43293320+e2dk4r@users.noreply.github.com>
Date: Mon, 28 Oct 2024 17:32:06 +0300
Subject: [PATCH] include: memory: fix segfault

We were calculating memory_chunk's block passed its memory limit. This
was causing unexpected memory overwrites.

- Re-enable allocation from stack
---
 include/memory.h |  2 +-
 src/main.c       | 11 ++---------
 2 files changed, 3 insertions(+), 10 deletions(-)

diff --git a/include/memory.h b/include/memory.h
index e0d3d9b..3432f7b 100644
--- a/include/memory.h
+++ b/include/memory.h
@@ -74,7 +74,7 @@ static struct memory_chunk *
 MemPushChunk(struct memory_block *mem, u64 size, u64 max)
 {
   struct memory_chunk *chunk = MemPush(mem, sizeof(*chunk) + max * sizeof(u8) + max * size);
-  chunk->block = chunk + sizeof(*chunk);
+  chunk->block = (u8*)chunk + sizeof(*chunk);
   chunk->size = size;
   chunk->max = max;
   for (u64 index = 0; index < chunk->max; index++) {
diff --git a/src/main.c b/src/main.c
index ca07d4b..7aabe19 100644
--- a/src/main.c
+++ b/src/main.c
@@ -337,14 +337,7 @@ main(int argc, char *argv[])
   memory.total = 1 * KILOBYTES;
 
   // OPTION A - allocate from stack
-  // BUG: allocate from stack
-  //   moving ls,rs on gamepad changes gamepad to invalid address SIGSEGV
-  //   problem fixed when using allocation from RAM (option B) instead of stack allocation.
-  //   reproduce steps:
-  //     1 - stop at memory allocation
-  //     2 - step through to first memcpy stdoutBuffer usage.
-  //         MemoryForDeviceOpenEvents->block will be overwritten.
-  if (0) {
+  if (1) {
     // - check limit
     struct rlimit rlim;
     if (getrlimit(RLIMIT_STACK, &rlim)) {
@@ -369,7 +362,7 @@ main(int argc, char *argv[])
   }
 
   // OPTION B - Allocate from RAM
-  if (1) {
+  else {
     memory.block = mmap(0, (size_t)memory.total, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
     if (!memory.block) {
       fatal("you do not have 1k memory available.\n");