Bump version to 2.0, update Changelog.md

Internally use doubly-linked list instead of singly-linked list. Also
minor fixes related to changing use to doubly-linked list.

Removed unnecessary comments.

Move list add/remove code to designated functions.

.gitignore

@@ -0,0 +1 @@
+/build*/

CMakeLists.txt

@@ -1,8 +1,8 @@
 cmake_minimum_required(VERSION 3.7)
 project(AnotherMemCheck)
 
-set(AnotherMemCheck_VERSION 1.0)
+set(AnotherMemCheck_VERSION 2.0)
-set(AnotherMemCheck_SOVERSION 1)
+set(AnotherMemCheck_SOVERSION 2)
 
 set(AnotherMemCheck_SOURCES
     "${CMAKE_CURRENT_SOURCE_DIR}/src/another_memcheck.cc"
@@ -28,3 +28,4 @@ set_target_properties(AnotherMemCheck PROPERTIES VERSION ${AnotherMemCheck_VERSI
                                                  SOVERSION ${AnotherMemCheck_SOVERSION})
 
 target_compile_features(AnotherMemCheck PUBLIC cxx_std_20)
+target_link_libraries(AnotherMemCheck PUBLIC pthread)

Changelog.md

@@ -1,5 +1,15 @@
 # Changelog
 
+## Version 2.0
+
+Minor refactorings.
+
+Change internal implementation of linked list to be doubly-linked.
+
+Add support for calloc.
+
+Add pthreads to mutex-lock malloc/calloc/free.
+
 ## Version 1.0
 
 Initial version with working `AnotherMemCheck`.

src/another_memcheck.cc

@@ -18,56 +18,114 @@ namespace SC_AM_Internal {
   }
 
   void *(*real_malloc)(std::size_t) = nullptr;
+  void *(*real_calloc)(std::size_t, std::size_t) = nullptr;
   void (*real_free)(void*) = nullptr;
 
   Malloced::Malloced() : address(nullptr), size(0) {}
   Malloced::Malloced(void *address, std::size_t size) : address(address), size(size) {}
 
-  Stats::Stats() : malloced_list(nullptr) {
+  void ListNode::add_to_list(ListNode *tail, Malloced *data) {
+    ListNode *new_node = reinterpret_cast<ListNode*>(real_malloc(sizeof(ListNode)));
+    new_node->next = tail;
+    new_node->prev = tail->prev;
+    tail->prev->next = new_node;
+    tail->prev = new_node;
+
+    new_node->data = data;
+  }
+
+  bool ListNode::remove_from_list(ListNode *head, void *ptr) {
+    ListNode *node = head;
+    while (node != nullptr) {
+      node = node->next;
+      if (node->data && node->data->address == ptr) {
+        node->prev->next = node->next;
+        node->next->prev = node->prev;
+        real_free(node->data);
+        real_free(node);
+        return true;
+      }
+    }
+
+    return false;
+  }
+
+  Stats::Stats() : malloced_list_head(nullptr), malloced_list_tail(nullptr), pthread_mutex{.__align=0} {
   }
 
   void Stats::initialize() {
-    malloced_list = reinterpret_cast<ListNode*>(real_malloc(sizeof(ListNode)));
+    malloced_list_head = reinterpret_cast<ListNode*>(real_malloc(sizeof(ListNode)));
-    malloced_list->next = nullptr;
+    malloced_list_tail = reinterpret_cast<ListNode*>(real_malloc(sizeof(ListNode)));
-    malloced_list->data = nullptr;
+    malloced_list_head->next = malloced_list_tail;
+    malloced_list_head->prev = nullptr;
+    malloced_list_tail->next = nullptr;
+    malloced_list_tail->prev = malloced_list_head;
+    malloced_list_head->data = nullptr;
+    malloced_list_tail->data = nullptr;
+
+    pthread_mutex_init(&pthread_mutex, nullptr);
+
     on_exit([] ([[maybe_unused]] int status, void *ptr) {
-      const Stats *stats = reinterpret_cast<const Stats*>(ptr);
+      Stats *stats = reinterpret_cast<Stats*>(ptr);
       stats->print_status();
+      stats->cleanup();
     }, this);
   }
 
+  void Stats::cleanup() {
+    pthread_mutex_destroy(&pthread_mutex);
+    // TODO maybe cleanup list, but it is the end of the program.
+  }
+
   void *Stats::do_malloc(std::size_t size) {
-    void *address = real_malloc(size);
+    if(int ret = pthread_mutex_lock(&pthread_mutex); ret == EINVAL) {
-    if (address != nullptr) {
+      std::clog << "ERROR: pthread mutex not properly initialized!\n";
-      auto *node = malloced_list;
+      return nullptr;
-      while (node->next != nullptr) {
-        node = node->next;
-      }
-      node->next = reinterpret_cast<ListNode*>(real_malloc(sizeof(ListNode)));
-      node->next->next = nullptr;
-      node->next->data = reinterpret_cast<Malloced*>(real_malloc(sizeof(Malloced)));
-      node->next->data->address = address;
-      node->next->data->size = size;
     }
 
+    void *address = real_malloc(size);
+    if (address != nullptr) {
+      Malloced *data = reinterpret_cast<Malloced*>(real_malloc(sizeof(Malloced)));
+      data->address = address;
+      data->size = size;
+      ListNode::add_to_list(malloced_list_tail, data);
+    }
+
+    pthread_mutex_unlock(&pthread_mutex);
+    return address;
+  }
+
+  void *Stats::do_calloc(std::size_t n, std::size_t size) {
+    if(int ret = pthread_mutex_lock(&pthread_mutex); ret == EINVAL) {
+      std::clog << "ERROR: pthread mutex not properly initialized!\n";
+      return nullptr;
+    }
+
+    void *address = real_calloc(n, size);
+    if (address != nullptr) {
+      Malloced *data = reinterpret_cast<Malloced*>(real_malloc(sizeof(Malloced)));
+      data->address = address;
+      data->size = size;
+      ListNode::add_to_list(malloced_list_tail, data);
+    }
+
+    pthread_mutex_unlock(&pthread_mutex);
     return address;
   }
 
   void Stats::do_free(void *ptr) {
+    if(int ret = pthread_mutex_lock(&pthread_mutex); ret == EINVAL) {
+      std::clog << "ERROR: pthread mutex not properly initialized!\n";
+      return;
+    }
+
     if (ptr) {
-      auto *node = malloced_list;
+      if(!ListNode::remove_from_list(malloced_list_head, ptr)) {
-      decltype(node) parent_node;
+        std::clog << "WARNING: Attempted free of unknown memory location!\n";
-      while (node->next != nullptr) {
-        parent_node = node;
-        node = node->next;
-        if (node->data && node->data->address == ptr) {
-          real_free(node->data);
-          parent_node->next = node->next;
-          real_free(node);
-          break;
-        }
       }
     }
+
+    pthread_mutex_unlock(&pthread_mutex);
   }
 
   void Stats::print_status() const {
@@ -75,11 +133,13 @@ namespace SC_AM_Internal {
     // it is expected for the OS to reclaim memory from stopped processes and
     // this function only runs at the end of program execution.
     std::clog << "List of unfreed memory:\n";
-    auto *node = malloced_list;
+    auto *node = malloced_list_head;
     while (node->next != nullptr) {
       node = node->next;
 
-      std::clog << "  " << node->data->address << ": size " << node->data->size << '\n';
+      if (node->data) {
+        std::clog << "  " << node->data->address << ": size " << node->data->size << '\n';
+      }
     }
   }
 }

src/another_memcheck.h

@@ -1,6 +1,10 @@
 #ifndef SEODISPARATE_COM_ANOTHER_MEMCHECK_H
 #define SEODISPARATE_COM_ANOTHER_MEMCHECK_H
 
+extern "C" {
+#include <pthread.h>
+}
+
 namespace SC_AM_Internal {
   // Forward declaration.
   struct Stats;
@@ -13,6 +17,7 @@ namespace SC_AM_Internal {
   constexpr unsigned int DATA_ITEMS_SIZE = 500;
 
   extern void *(*real_malloc)(std::size_t size);
+  extern void *(*real_calloc)(std::size_t n, std::size_t size);
   extern void (*real_free)(void *ptr);
 
   struct Malloced {
@@ -24,22 +29,30 @@ namespace SC_AM_Internal {
   };
 
   struct ListNode {
-    ListNode() : next(nullptr), data(nullptr) {}
+    ListNode() : next(nullptr), prev(nullptr), data(nullptr) {}
+
+    static void add_to_list(ListNode *tail, Malloced *data);
+    /// Returns true if removed.
+    static bool remove_from_list(ListNode *head, void *ptr);
 
     ListNode *next;
+    ListNode *prev;
     Malloced *data;
   };
 
-  using MapDataType = std::pair<const void*, Malloced>;
 
   struct Stats {
     Stats();
 
-    ListNode *malloced_list;
+    ListNode *malloced_list_head;
+    ListNode *malloced_list_tail;
+    pthread_mutex_t pthread_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_free(void *ptr);
 
     void print_status() const;

src/another_memcheck_external.cc

@@ -1,7 +1,5 @@
 // Standard library includes.
 #include <iostream>
-/*#include <cstdlib>*/
-/*#include <cstdio>*/
 
 // Unix includes.
 #include <dlfcn.h>
@@ -24,6 +22,21 @@ extern "C" {
     return SC_AM_Internal::stats->do_malloc(size);
   }
 
+  void *calloc(std::size_t n, std::size_t size) {
+    std::clog << "attempting to calloc size: " << size << "...\n";
+
+    if (SC_AM_Internal::real_calloc == nullptr) {
+      SC_AM_Internal::real_calloc = reinterpret_cast<void*(*)(std::size_t, std::size_t)>(
+          dlsym(RTLD_NEXT, "calloc"));
+    }
+
+    if (SC_AM_Internal::stats == nullptr) {
+      SC_AM_Internal::stats = SC_AM_Internal::get_init_stats();
+    }
+
+    return SC_AM_Internal::stats->do_calloc(n, size);
+  }
+
   void free(void *ptr) {
     std::clog << "attempting to free...\n";