Enable guard page + bail:meme with stack traces

rust/ares/src/guard.rs

@@ -43,15 +43,6 @@ impl<'closure> CCallback<'closure> {
     {
         let function: unsafe extern "C" fn(*mut c_void) -> *mut c_void = Self::call_closure::<F>;
 
-        // debug_assert_eq!(
-        //     std::mem::size_of::<&'closure mut F>(),
-        //     std::mem::size_of::<*const c_void>()
-        // );
-        // debug_assert_eq!(
-        //     std::mem::size_of_val(&function),
-        //     std::mem::size_of::<*const c_void>()
-        // );
-
         Self {
             function,
             input: closure as *mut F as *mut c_void,
@@ -91,12 +82,7 @@ pub fn call_with_guard<F: FnMut() -> Result>(
             ret_pp,
         );
 
-        // eprintln!("\r BEFORE:");
-        // eprintln!("\r ret = {:?}", ret);
-        // eprintln!("\r ret_p = {:p}, {:?}", ret_p as *mut Result, *(ret_p as *mut Result));
-        // eprintln!("\r ret_pp = {:p}, {:p}, {:?}", ret_pp, *ret_pp, **(ret_pp as *mut *mut Result));
         if res == 0 {
-            // TODO: come back to this
             permit_alloc(|| {
                 let result_box = Box::from_raw(ret_p as *mut Result);
                 *result_box

rust/ares/src/interpreter.rs

@@ -1191,6 +1191,7 @@ fn exit(
             Error::Deterministic(_, t) | Error::NonDeterministic(_, t) | Error::ScryCrashed(t) => {
                 // Return $tang of traces
                 let h = *(stack.local_noun_pointer(0));
+                // XX: Small chance of clobbering something important after OOM?
                 T(stack, &[h, t])
             }
         };

rust/ares_guard/c-src/guard.c

@@ -15,10 +15,10 @@
 #define GD_PAGE_MASK              (GD_PAGE_SIZE - 1)
 #define GD_PAGE_ROUND_DOWN(foo)   (foo & (~GD_PAGE_MASK))
 
-static uintptr_t         guard_p;
-static const uintptr_t  *stack_pp;
-static const uintptr_t  *alloc_pp;
-static jmp_buf           env_buffer;
+static uintptr_t         guard_p = 0;
+static const uintptr_t  *stack_pp = NULL;
+static const uintptr_t  *alloc_pp = NULL;
+static BufListNode      *buffer_list = NULL;
 static struct sigaction  prev_sa;
 
 static int32_t
@@ -113,7 +113,7 @@ _signal_handler(int sig, siginfo_t *si, void *unused)
   if (sig != SIGSEGV) {
     fprintf(stderr, "guard: sig_handle: invalid signal\r\n");
     // XX: do we even want to jump? if this is fatal error, maybe just die now
-    siglongjmp(env_buffer, guard_signal);
+    siglongjmp(buffer_list->buffer, guard_signal);
   }
 
   sig_addr = (uintptr_t)si->si_addr;
@@ -126,7 +126,7 @@ _signal_handler(int sig, siginfo_t *si, void *unused)
     err = _focus_guard();
     if (err) {
       fprintf(stderr, "guard: sig_handle: focus error\r\n");
-      siglongjmp(env_buffer, err);
+      siglongjmp(buffer_list->buffer, err);
     }
   }
   else {
@@ -159,7 +159,7 @@ _register_handler()
   // sigemptyset(&sa.sa_mask);
   // sigaddset(&(sa.sa_mask), SIGSEGV);
 
-  // XX: should assert that prev_sa doesn't have a handler in it, but it's not a pointer so non-trivial
+  // XX: should assert that prev_sa is uninitialized, but it's not a pointer so non-trivial
   if (sigaction(SIGSEGV, &sa, &prev_sa)) {
     fprintf(stderr, "guard: register: sigaction error\r\n");
     fprintf(stderr, "%s\r\n", strerror(errno));
@@ -177,51 +177,84 @@ guard(
   const uintptr_t *const a_pp,
   void ** ret
 ) {
-  int32_t err = 0;
-  int32_t td_err;
+  BufListNode  *new_buffer;
+  int32_t       err = 0;
+  int32_t       td_err = 0;
 
-  assert(guard_p == 0);
-  fprintf(stderr, "guard: setup: stack pointer at %p\r\n", (void *)(*stack_pp));
-  fprintf(stderr, "guard: setup: alloc pointer at %p\r\n", (void *)(*alloc_pp));
+  fprintf(stderr, "guard: setup: stack pointer at %p\r\n", (void *)(*s_pp));
+  fprintf(stderr, "guard: setup: alloc pointer at %p\r\n", (void *)(*a_pp));
 
-  guard_p = 0;
-  stack_pp = s_pp;
-  alloc_pp = a_pp;
+  if (guard_p == 0) {
+    assert(buffer_list == NULL);
 
-  // Initialize the guard page
-  if ((err = _focus_guard())) {
-    fprintf(stderr, "guard: setup: _focus_guard error\r\n");
-    goto done;
+    stack_pp = s_pp;
+    alloc_pp = a_pp;
+
+    // Initialize the guard page
+    if ((err = _focus_guard())) {
+      fprintf(stderr, "guard: setup _focus_guard error\r\n");
+      goto exit;
+    }
+
+    // Register guard page signal handler
+    if ((err = _register_handler())) {
+      fprintf(stderr, "guard: setup _register_handler error\r\n");
+      goto clean;
+    }
+  } else {
+    assert(buffer_list != NULL);
   }
 
-  // Register guard page signal handler
-  if ((err = _register_handler())) {
-    fprintf(stderr, "guard: setup: _register_handler error\r\n");
-    goto done;
+  // Setup new longjmp buffer
+  new_buffer = (BufListNode *)malloc(sizeof(BufListNode));
+  if (new_buffer == NULL) {
+    fprintf(stderr, "guard: malloc error\r\n");
+    fprintf(stderr, "%s\r\n", strerror(errno));
+    err = guard_malloc | errno;
+    goto skip;
   }
+  new_buffer->next = buffer_list;
+  buffer_list = new_buffer;
 
   // Run given closure
   fprintf(stderr, "guard: run\r\n");
-  if (!(err = sigsetjmp(env_buffer, 1))) {
+  if (!(err = sigsetjmp(buffer_list->buffer, 1))) {
     *ret = f(closure);
   }
 
-done:
-  // Clean up
-  if (guard_p != 0) {
+  // Restore previous longjmp buffer
+  buffer_list = buffer_list->next;
+  free((void *)new_buffer);
+
+skip:
+  // If no more guarded closures, then...
+  if (buffer_list == NULL) {
+    // Remove new signal handler
+    if (sigaction(SIGSEGV, &prev_sa, NULL)) {
+      fprintf(stderr, "guard: sigaction error\r\n");
+      fprintf(stderr, "%s\r\n", strerror(errno));
+      td_err = guard_sigaction | errno;
+
+      if (!err) {
+        err = td_err;
+      }
+    }
+
+clean:
+    // Unmark guard page
+    assert(guard_p != 0);
     td_err = _unmark_page((void *)guard_p);
+    if (td_err) {
+      fprintf(stderr, "guard: unmark error\r\n");
+      fprintf(stderr, "%s\r\n", strerror(errno));
+      if (!err) {
+        err = td_err;
+      }
+    }
+    guard_p = 0;
   }
 
-  if (sigaction(SIGSEGV, &prev_sa, NULL)) {
-    fprintf(stderr, "guard: teardown: sigaction error\r\n");
-    fprintf(stderr, "%s\r\n", strerror(errno));
-    td_err = guard_sigaction | errno;
-  }
-
-  if (!err) {
-    err = td_err;
-  }
-
+exit:
   fprintf(stderr, "guard: return\r\n");
   return err;
 }

rust/ares_guard/c-src/guard.h

@@ -1,8 +1,17 @@
 #ifndef __GUARD_H__
 #define __GUARD_H__
 
+#include <setjmp.h>
 #include <stdint.h>
 
+/**
+ * 
+ */
+typedef struct _buf_list_node {
+  jmp_buf                 buffer;
+  struct _buf_list_node  *next;
+} BufListNode;
+
 /**
  * Error codes and flags.
  *

rust/rust-assert-no-alloc/src/lib.rs

@@ -91,7 +91,6 @@ pub fn assert_no_alloc<T, F: FnOnce() -> T> (func: F) -> T {
 	return ret;
 }
 
-#[cfg(not(all(feature = "disable_release", not(debug_assertions))))] // if not disabled
 /// Calls the `func` closure, but ensures that the forbid and permit counters
 /// are maintained accurately even if a longjmp originates and terminates
 /// within the closure. If you longjmp over this function, we can't fix
@@ -149,14 +148,6 @@ pub fn reset_violation_count() {
 	ALLOC_VIOLATION_COUNT.with(|c| c.set(0));
 }
 
-pub fn reset_counters() {
-	ALLOC_FORBID_COUNT.with(|c| c.set(0));
-	ALLOC_PERMIT_COUNT.with(|c| c.set(0));
-
-	#[cfg(any( all(feature="warn_debug", debug_assertions), all(feature="warn_release", not(debug_assertions)) ))]
-	ALLOC_VIOLATION_COUNT.with(|c| c.set(0));
-}
-