Update Changelog.md, version 2.8

Avoids segfault by not freeing the internal structure handling memory
allocations. When the process ends, the OS should reclaim all memory,
even if it isn't free'd during process execution.

CMakeLists.txt

@@ -1,7 +1,7 @@
 cmake_minimum_required(VERSION 3.7)
 project(AnotherMemCheck)
 
-set(AnotherMemCheck_VERSION 2.7)
+set(AnotherMemCheck_VERSION 2.8)
 set(AnotherMemCheck_SOVERSION 2)
 
 set(AnotherMemCheck_SOURCES

Changelog.md

@@ -1,5 +1,11 @@
 # Changelog
 
+## Version 2.8
+
+Internal refactorings.
+
+Minor change to avoid segfault when program exits with `exit(...)` function.
+
 ## Version 2.7
 
 Fix incorrect initialization.

src/another_memcheck.cc

@@ -8,6 +8,9 @@
 // Local includes.
 #include "another_memcheck.h"
 
+// Function declaration.
+void exit_handler_stats();
+
 namespace SC_AM_Internal {
   Stats *stats = nullptr;
   int is_env_status = 0;
@@ -16,7 +19,7 @@ namespace SC_AM_Internal {
   Stats *get_init_stats() {
     Stats *stats = reinterpret_cast<SC_AM_Internal::Stats*>(
         real_malloc(sizeof(Stats)));
-    stats->initialize();
+    [[maybe_unused]] void *unused = new(stats) Stats{};
     is_env_status = getenv("ANOTHER_MEMCHECK_QUIET") != nullptr
       ? ANOTHER_MEMCHECK_QUIET_EXISTS
       : ANOTHER_MEMCHECK_QUIET_NOT_EXISTS;
@@ -77,9 +80,6 @@ namespace SC_AM_Internal {
   }
 
   Stats::Stats() : malloced_list_head(nullptr), malloced_list_tail(nullptr), deferred_node(nullptr), recursive_mutex(nullptr) {
-  }
-
-  void Stats::initialize() {
     malloced_list_head = reinterpret_cast<ListNode*>(real_malloc(sizeof(ListNode)));
     malloced_list_tail = reinterpret_cast<ListNode*>(real_malloc(sizeof(ListNode)));
     malloced_list_head->next = malloced_list_tail;
@@ -92,17 +92,12 @@ namespace SC_AM_Internal {
     deferred_node = nullptr;
 
     recursive_mutex = real_malloc(sizeof(std::recursive_mutex));
-    void *unused = new(recursive_mutex) std::recursive_mutex{};
+    [[maybe_unused]] void *unused = new(recursive_mutex) std::recursive_mutex{};
-    (void)unused;
 
-    on_exit([] ([[maybe_unused]] int status, void *ptr) {
+    std::atexit(exit_handler_stats);
-      Stats *stats = reinterpret_cast<Stats*>(ptr);
-      stats->print_status();
-      stats->cleanup();
-    }, this);
   }
 
-  void Stats::cleanup() {
+  Stats::~Stats() {
     using std_recursive_mutex = std::recursive_mutex;
     ((std::recursive_mutex*)recursive_mutex)->~std_recursive_mutex();
     real_free(recursive_mutex);
@@ -218,4 +213,17 @@ namespace SC_AM_Internal {
   }
 }
 
+// Function definition.
+void exit_handler_stats() {
+  if (SC_AM_Internal::stats != nullptr) {
+    SC_AM_Internal::stats->print_status();
+
+    // Avoids segfault when program calls `exit(...)`. OS should reclaim memory
+    // when the process ends even if it isn't free'd here.
+    //using SCS_AM_INTERNAL_Stats = SC_AM_Internal::Stats;
+    //SC_AM_Internal::stats->~SCS_AM_INTERNAL_Stats();
+    //SC_AM_Internal::stats = nullptr;
+  }
+}
+
 // vim: et sw=2 ts=2 sts=2

src/another_memcheck.h

@@ -1,6 +1,8 @@
 #ifndef SEODISPARATE_COM_ANOTHER_MEMCHECK_H
 #define SEODISPARATE_COM_ANOTHER_MEMCHECK_H
 
+#include <cstdint>
+
 namespace SC_AM_Internal {
   // Forward declaration.
   struct Stats;
@@ -48,15 +50,21 @@ namespace SC_AM_Internal {
 
   struct Stats {
     Stats();
+    ~Stats();
+
+    // Disable copy.
+    Stats(Stats &other) = delete;
+    Stats& operator=(Stats &other) = delete;
+
+    // Disable move.
+    Stats(Stats &&other) = delete;
+    Stats& operator=(Stats &&other) = delete;
 
     ListNode *malloced_list_head;
     ListNode *malloced_list_tail;
     ListNode *deferred_node;
     void *recursive_mutex;
 
-    void initialize();
-    void cleanup();
-
     void *do_malloc(std::size_t size);
     void *do_calloc(std::size_t n, std::size_t size);
     void *do_realloc(void*, std::size_t size);