.gitignore

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

CMakeLists.txt

@@ -1,8 +1,8 @@
 cmake_minimum_required(VERSION 3.7)
 project(AnotherMemCheck)
 
-set(AnotherMemCheck_VERSION 2.0)
-set(AnotherMemCheck_SOVERSION 2)
+set(AnotherMemCheck_VERSION 1.0)
+set(AnotherMemCheck_SOVERSION 1)
 
 set(AnotherMemCheck_SOURCES
     "${CMAKE_CURRENT_SOURCE_DIR}/src/another_memcheck.cc"
@@ -28,4 +28,3 @@ 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

@@ -1,15 +1,5 @@
 # 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

@@ -18,114 +18,56 @@ 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) {}
 
-  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} {
+  Stats::Stats() : malloced_list(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;
-    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);
-
+    malloced_list = reinterpret_cast<ListNode*>(real_malloc(sizeof(ListNode)));
+    malloced_list->next = nullptr;
+    malloced_list->data = nullptr;
     on_exit([] ([[maybe_unused]] int status, void *ptr) {
-      Stats *stats = reinterpret_cast<Stats*>(ptr);
+      const Stats *stats = reinterpret_cast<const 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) {
-    if(int ret = pthread_mutex_lock(&pthread_mutex); ret == EINVAL) {
-      std::clog << "ERROR: pthread mutex not properly initialized!\n";
-      return nullptr;
-    }
-
     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);
+      auto *node = malloced_list;
+      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;
     }
 
-    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) {
-      if(!ListNode::remove_from_list(malloced_list_head, ptr)) {
-        std::clog << "WARNING: Attempted free of unknown memory location!\n";
+      auto *node = malloced_list;
+      decltype(node) parent_node;
+      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 {
@@ -133,15 +75,13 @@ 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_head;
+    auto *node = malloced_list;
     while (node->next != nullptr) {
       node = node->next;
 
-      if (node->data) {
       std::clog << "  " << node->data->address << ": size " << node->data->size << '\n';
     }
   }
 }
-}
 
 // vim: et sw=2 ts=2 sts=2

src/another_memcheck.h

@@ -1,10 +1,6 @@
 #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;
@@ -17,7 +13,6 @@ 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 {
@@ -29,30 +24,22 @@ namespace SC_AM_Internal {
   };
 
   struct ListNode {
-    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(nullptr), data(nullptr) {}
 
     ListNode *next;
-    ListNode *prev;
     Malloced *data;
   };
 
+  using MapDataType = std::pair<const void*, Malloced>;
 
   struct Stats {
     Stats();
 
-    ListNode *malloced_list_head;
-    ListNode *malloced_list_tail;
-    pthread_mutex_t pthread_mutex;
+    ListNode *malloced_list;
 
     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

@@ -1,5 +1,7 @@
 // Standard library includes.
 #include <iostream>
+/*#include <cstdlib>*/
+/*#include <cstdio>*/
 
 // Unix includes.
 #include <dlfcn.h>
@@ -22,21 +24,6 @@ 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";