From 3f6d76b6992c6abced8aadea366d5f2ad9e8ce8f Mon Sep 17 00:00:00 2001
From: Matthew LeVan <matthew@coeli.network>
Date: Mon, 5 Feb 2024 17:29:44 -0500
Subject: [PATCH] wip: sigbus on guard hit?

---
 rust/ares/Cargo.toml          |  4 ++--
 rust/ares/src/serf.rs         |  2 +-
 rust/ares_guard/c-src/guard.c | 20 ++++++++++++--------
 3 files changed, 15 insertions(+), 11 deletions(-)

diff --git a/rust/ares/Cargo.toml b/rust/ares/Cargo.toml
index ba1a059..733b43f 100644
--- a/rust/ares/Cargo.toml
+++ b/rust/ares/Cargo.toml
@@ -44,10 +44,10 @@ name = "ares"
 path = "src/main.rs"
 
 [profile.dev]
-opt-level = 3
+opt-level = 0
 
 [profile.dev.package."*"]
-opt-level = 3
+opt-level = 0
 
 # run with e.g. 'cargo build --features check_forwarding,check_acyclic'
 [features]
diff --git a/rust/ares/src/serf.rs b/rust/ares/src/serf.rs
index ef83d79..3ca2822 100644
--- a/rust/ares/src/serf.rs
+++ b/rust/ares/src/serf.rs
@@ -143,7 +143,7 @@ impl Context {
         snapshot: Option<Snapshot>,
         constant_hot_state: &[HotEntry],
     ) -> Self {
-        let mut stack = NockStack::new(256 << 10 << 10, 0);
+        let mut stack = NockStack::new(128 << 10 << 10, 0);
         let newt = Newt::new();
         let cache = Hamt::<Noun>::new(&mut stack);
 
diff --git a/rust/ares_guard/c-src/guard.c b/rust/ares_guard/c-src/guard.c
index 26f6bee..0ee039d 100644
--- a/rust/ares_guard/c-src/guard.c
+++ b/rust/ares_guard/c-src/guard.c
@@ -50,20 +50,24 @@ _focus_guard()
     }
   }
 
-  // Place the new guard page in the low-aligned center.
+  // Calculate the new center for the guard page.
   guard_p = (uint64_t *)low_p + ((high_p - low_p) / 2);
   guard_p = (uint64_t *)((uintptr_t)guard_p & ~(GD_PAGESIZE - 1));
 
-  // Mark the new guard page.
-  if (guard_p != old_guard_p) {
-    fprintf(stderr, "guard: focused guard page\r\n");
+  // Place the new guard page or return if we're spent.
+  bool spent = false;
+  const bool same = old_guard_p == guard_p;
+  const bool left = (high_p - low_p) > GD_PAGESIZE;
+  if (same && !left) {
+    fprintf(stderr, "guard: spent: %p; left: %u\r\n", guard_p, left);
+    return guard_spent;
+  }
+  else {
+    fprintf(stderr, "guard: high: %p; low: %p\r\n", high_p, low_p);
+    fprintf(stderr, "guard: focused: %p; left: %u\r\n", guard_p, left);
     if (mprotect(guard_p, GD_PAGESIZE, PROT_NONE) == -1) {
       return guard_armor;
     }
-  } else {
-    fprintf(stderr, "guard: spent; exiting\r\n");
-    exit(1);
-    return guard_spent;
   }
 
   return guard_sound;