From 544aefb1f900d9c746ff0b1647cc418245bb5b48 Mon Sep 17 00:00:00 2001
From: Alessandre Laguierce <alessandre.laguierce@enseirb-matmeca.fr>
Date: Thu, 20 Mar 2025 20:49:50 +0100
Subject: [PATCH] fix: valgrind-friendly <3

---
 src/thread/thread.c | 22 ++++++++++++++++++++--
 1 file changed, 20 insertions(+), 2 deletions(-)

diff --git a/src/thread/thread.c b/src/thread/thread.c
index 3fbf083..0e1c9fe 100644
--- a/src/thread/thread.c
+++ b/src/thread/thread.c
@@ -7,6 +7,7 @@
 #include <bits/pthreadtypes.h>
 #include <stdlib.h>
 #include <ucontext.h>
+#include <valgrind/valgrind.h>
 
 #ifndef STACK_SIZE
 #define STACK_SIZE 4096*4
@@ -16,8 +17,10 @@ struct context_entry {
   ucontext_t context;
   thread_t id;
   thread_t parent;
+  int was_allocated;
   int finished;
   void *retvalue;
+  int valgrind_id;
   TAILQ_ENTRY(context_entry) link;
 };
 
@@ -60,6 +63,10 @@ int thread_create(thread_t *newthread, void *(*func)(void *), void *funcarg) {
     struct context_entry *main = malloc(sizeof(*main));
     getcontext(&main->context);
     main->id = 0;
+    main->parent = 0;
+    main->finished = 0;
+    main->retvalue = 0;
+    main->was_allocated = 0;
     TAILQ_INSERT_HEAD(&head, main, link);
     running = main;
     counter++;
@@ -68,10 +75,15 @@ int thread_create(thread_t *newthread, void *(*func)(void *), void *funcarg) {
   getcontext(&new_entry->context);
   new_entry->context.uc_stack.ss_sp = malloc(STACK_SIZE);
   new_entry->context.uc_stack.ss_size = STACK_SIZE;
+  new_entry->valgrind_id = VALGRIND_STACK_REGISTER(
+    new_entry->context.uc_stack.ss_sp,
+    new_entry->context.uc_stack.ss_sp + new_entry->context.uc_stack.ss_size
+    );
   new_entry->id = new_entry;
   new_entry->parent = running->id;
   new_entry->finished = 0;
   new_entry->retvalue = 0;
+  new_entry->was_allocated = 1;
   *newthread = new_entry;
   makecontext(&new_entry->context, (void (*)()) func, 1, funcarg);
   counter++;
@@ -96,11 +108,17 @@ int thread_join(thread_t thread, void **retval) {
     if (retval)
       *retval = entry->retvalue;
     TAILQ_REMOVE(&head, entry, link);
-    free(entry->context.uc_stack.ss_sp);
+    if (entry->was_allocated) {
+      VALGRIND_STACK_DEREGISTER(entry->valgrind_id);
+      free(entry->context.uc_stack.ss_sp);
+    }
     free(entry);
     if (--counter == 1) {
       TAILQ_REMOVE(&head, running, link);
-      free(running->context.uc_stack.ss_sp);
+      if (running->was_allocated) {
+        VALGRIND_STACK_DEREGISTER(running->valgrind_id);
+        free(running->context.uc_stack.ss_sp);
+      }
       free(running);
       running = 0;
       counter = 0;