1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Memory Leak detection Program without using any tools

Discussion in 'C' started by asadullah.ansari, Mar 4, 2008.

  1. asadullah.ansari

    asadullah.ansari TechCake

    Joined:
    Jan 9, 2008
    Messages:
    356
    Likes Received:
    14
    Trophy Points:
    0
    Occupation:
    Developer
    Location:
    NOIDA
    I worked for a long time for this article. This program is tested on Sun-Solaris system using gcc compiler.

    In market, there are a lot of tools for detecting the memory leaks. Here I made a program which has to include in your source file and it will tell the desired informations to find where memory leaks happen.

    There are two files one is findLeak.c and other is findLeak.h . Source file is test.c , this is your program which you want to check memory leaks.

    Concept is that when user call library function "malloc or calloc " for allocating dynamic memory, then we have to call our malloc or calloc (In case of my source code 'MyCalloc' function in place of 'calloc' and MyMalloc function in place of 'malloc'). So we have to define malloc to your malloc and in .c file you have to undef malloc and calloc By this way we can call our MyMalloc or MyCalloc function and in this function we will call another function which keeps all info about how much memory allocated. We will do the same for Library function "free" to deallocating memory( In my source file "MyFree" is used in plae of free function).

    Now for keeping information, i made a simple singly linked list. which will add info about memory when user call "malloc" or "calloc" function and will also keep information when user call "free" function.

    By program you can easily understand.

    Heder File : findLeak.h

    Code:
    
    #define   uint                 unsigned int 
    #define   cchar                const char                     
    #define   OutFile             "/home/asadulla/test/MemLeakInfo.txt"   // Just Suppose
    #define  MAX_FILENAME_LENGTH   256
    #define  calloc(objs, nSize) 	      MyCalloc (objs, nSize, __FILE__, __LINE__)
    #define  malloc(nSize) 	    	         MyMalloc (nSize, __FILE__, __LINE__)
    #define  free(rMem) 		          MyFree(rMem)
    
    // This structure is keeping info about memory leak
    
    struct InfoMem
    {
          //starting address of memory where pointer points 
        void *addr; 
          //Total size of memory in bytes which By malloc 
          //allocates  memory dynamically */
    	uint nSize; 
          //Source File Name which you want
          //to  find memory leak information 
    	char fileName[MAX_FILENAME_LENGTH]; 
            //Line number of source File due to                                                                             
           // which User forget to deallocate   memory 
    	uint lineNumber; 
    };
    typedef struct InfoMem infoMem;
    
    //This is link list of InfoMem which keeps a List of memory Leak in a source file
    
    struct LeakMem
    {
    	infoMem memData;     
    	struct LeakMem *nxt;   // Next Memory leak Block
    };
    typedef struct LeakMem leakMem;
    
    // This function is used for writing into file to see the memory leaks summary
    void WriteMemLeak(void);
    
    // These two function add information of memory leak information when user 
    // calls malloc or calloc
    void SubAddMemInfo(void *rMem, uint nSize,  cchar  *file, uint lno);
    void SubAdd(infoMem alloc_info);
    
    // These two function remove and deallocated  memory and remove the leak 
    //  information when user calls free function
    void ResetInfo(uint pos); //erase
    void DeleteAll(void); //clear(void);
    
    // This is hidden to user , This function will call when user call malloc function
    void *MyMalloc(uint size, cchar *file, uint line);
    // This is hidden to user , This function will call when user call calloc function
    void *MyCalloc(uint elements, uint size, cchar * file, uint lno);
    // This is hidden to user , This function will call when user call free function
    void  MyFree(void * mem_ref);
    
    
    Source File: findLeak.c

    Code:
    #include	<stdio.h>
    #include	<malloc.h>
    #include	<string.h>
    #include	"findLeak.h"
    
    #undef		malloc
    #undef		calloc
    #undef 		free
    
    
    static leakMem * ptr_start = NULL;
    static leakMem * ptr_next =  NULL;
    
    
    
    
    // -----------------------------------------------------------
    // Name: MyMalloc
    // Desc: This is hidden to user. when user call malloc function then 
    //       this function will be called.
    
    
    void *MyMalloc (uint nSize, cchar* file, uint lineNumber)
    {
    	void * ptr = malloc (nSize);
    	if (ptr != NULL) 
    	{
    		SubAddMemInfo(ptr, nSize, file, lineNumber);
    	}
    	return ptr;
    }
    
    // -----------------------------------------------------------
    // Name: MyCalloc
    // Desc: This is hidden to user. when user call calloc function then 
    //       this function will be called.
    
    
    void * MyCalloc (uint elements, uint nSize, const char * file, uint lineNumber)
    {
    	uint tSize;
    	void * ptr = calloc(elements , nSize);
    	if(ptr != NULL)
    	{
    		tSize = elements * nSize;
    		SubAddMemInfo (ptr, tSize, file, lineNumber);
    	}
    	return ptr;
    }
    
    // -----------------------------------------------------------
    // Name: SubAdd
    // Desc: It's actually  Adding the Info.
    
    
    void SubAdd(infoMem alloc_info)
    {
    	leakMem * mem_leak_info = NULL;
    	mem_leak_info = (leakMem *) malloc (sizeof(leakMem));
    	mem_leak_info->memData.addr = alloc_info.addr;
    	mem_leak_info->memData.nSize = alloc_info.nSize;
    	strcpy(mem_leak_info->memData.fileName, alloc_info.fileName); 
    	mem_leak_info->memData.lineNumber = alloc_info.lineNumber;
    	mem_leak_info->nxt = NULL;
    
    	if (ptr_start == NULL)	
    	{
    		ptr_start = mem_leak_info;
    		ptr_next = ptr_start;
    	}
    	else {
    		ptr_next->nxt = mem_leak_info;
    		ptr_next = ptr_next->nxt;				
    	}
    
    }
    
    
    
    // -----------------------------------------------------------
    // Name: ResetInfo
    // Desc: It erasing the memory using by List on the basis of info( pos)
    
    
    void ResetInfo(uint pos)
    {
    
    	uint index = 0;
    	leakMem * alloc_info, * temp;
    	
    	if(pos == 0)
    	{
    		leakMem * temp = ptr_start;
    		ptr_start = ptr_start->nxt;
    		free(temp);
    	}
    	else 
    	{
    		for(index = 0, alloc_info = ptr_start; index < pos; 
    			alloc_info = alloc_info->nxt, ++index)
    		{
    			if(pos == index + 1)
    			{
    				temp = alloc_info->nxt;
    				alloc_info->nxt =  temp->nxt;
    				free(temp);
    				break;
    			}
    		}
    	}
    }
    
    // -----------------------------------------------------------
    // Name: DeleteAll
    // Desc: It deletes the all elements which resides on List
    
    void DeleteAll()
    {
    	leakMem * temp = ptr_start;
    	leakMem * alloc_info = ptr_start;
    
    	while(alloc_info != NULL) 
    	{
    		alloc_info = alloc_info->nxt;
    		free(temp);
    		temp = alloc_info;
    	}
    }
    
    
    // -----------------------------------------------------------
    // Name: MyFree
    // Desc: 
    
    
    void MyFree(void * mem_ref)
    {
    		uint loop;
       // if the allocated memory info is part of the list, removes it
    	leakMem  *leak_info = ptr_start;
    	/* check if allocate memory is in our list */
    	for(loop = 0; leak_info != NULL; ++loop, leak_info = leak_info->nxt)
    	{
    		if ( leak_info->memData.addr == mem_ref )
    		{
    			ResetInfo(loop);
    			break;
    		}
    	}
    	free(mem_ref);
    }
    
    
    // -----------------------------------------------------------
    // Name: SubAddMemInfo
    // Desc: it also fill the the Info
    
    
    void SubAddMemInfo (void * mem_ref, uint nSize, cchar * file, uint lineNumber)
    {
    	infoMem AllocInfo;
    
    	/* fill up the structure with all info */
    	memset( &AllocInfo, 0, sizeof ( AllocInfo ) );
    	AllocInfo.addr 	= mem_ref;
    	AllocInfo.nSize = nSize;
    	strncpy(AllocInfo.fileName, file, MAX_FILENAME_LENGTH);
    	AllocInfo.lineNumber = lineNumber;
    	
    	/* SubAdd the above info to a list */
    	SubAdd(AllocInfo);
    }
    
    // -----------------------------------------------------------
    // Name: WriteMemLeak
    // Desc: It writes information about Memory leaks in a file 
    //       Example: File is as : "/home/asadulla/test/MemLeakInfo.txt"
    
    
    
    void WriteMemLeak(void)
    {
    	uint index;
    	leakMem *leak_info;
    
    	FILE * fp_write = fopen(OutFile, "wt");
    	char info[1024];
    
    	if(fp_write != NULL)
    	{
    		sprintf(info, "%s\n", "SUMMARY ABOUT MEMORY LEAKS OF YOUR SOURCE FILE ");
    		fwrite(info, (strlen(info) + 1) , 1, fp_write);
    		sprintf(info, "%s\n", "-----------------------------------");	
    		fwrite(info, (strlen(info) + 1) , 1, fp_write);
    		
    		for(leak_info = ptr_start; leak_info != NULL; leak_info = leak_info->nxt)
    		{
    
    			sprintf(info, "Name of your Source File                 : %s\n", leak_info->memData.fileName);
    			fwrite(info, (strlen(info) + 1) , 1, fp_write);
    
    			sprintf(info, "Starting Address                         : %d\n", leak_info->memData.addr);
    			fwrite(info, (strlen(info) + 1) , 1, fp_write);
    
    			sprintf(info, " Total size Of memory Leak               : %d bytes\n", leak_info->memData.nSize);			
    			fwrite(info, (strlen(info) + 1) , 1, fp_write);
    
    			sprintf(info, "Line Number for which no DeAllocation    : %d\n", leak_info->memData.lineNumber);
    			fwrite(info, (strlen(info) + 1) , 1, fp_write);
    
    			sprintf(info, "%s\n", "-----------------------------------");	
    			fwrite(info, (strlen(info) + 1) , 1, fp_write);
          fwrite(info, (strlen(info) + 1) , 1, fp_write);
    		}
    	}	
    	DeleteAll();
    }
    
    These two files (header file and source file) user has to include in his source file to which user want to find memory leak.

    Source File for detecting memory leak is as Here you can gice your own source file and in this source file you have write onle line to include file #include"findLeak.h"


    Source File : test.c

    Code:
    
    #include<malloc.h>
    #include"findLeak.h"
    
    int main()
    {
    	int *p1 = (int *)malloc(10);  
    	int *p2 = (int *)calloc(10, sizeof(int));
        char *p3 = (char *) calloc(15, sizeof(float));
        float *p4 = (float*) malloc(16);
    	free(p2);
        WriteMemLeak();
    	return 0;
     }
    
    

    Now user can compile these programmes in a console as :
    > g++ test.c findLeak.c
    and give a command for run
    > ./a.out

    then go to you your directory where you have defined a macro "OutFile" and open this defined file and you can see the results.

    Output of above source file is as:

    Code:
    
    SUMMARY ABOUT MEMORY LEAKS OF YOUR SOURCE FILE 
    -----------------------------------
    Name of your Source File                 : test.c
    Starting Address                         : 184960
     Total size Of memory Leak               : 10 bytes
    Line Number for which no DeAllocation    : 7
    -----------------------------------
    -----------------------------------
    Name of your Source File                 : test.c
    Starting Address                         : 187104
     Total size Of memory Leak               : 60 bytes
    Line Number for which no DeAllocation    : 9
    -----------------------------------
    -----------------------------------
    Name of your Source File                 : test.c
    Starting Address                         : 184984
     Total size Of memory Leak               : 16 bytes
    Line Number for which no DeAllocation    : 10
    -----------------------------------
    -----------------------------------
    
    Now you can try to make you own source file just like test.c.
     
  2. asadullah.ansari

    asadullah.ansari TechCake

    Joined:
    Jan 9, 2008
    Messages:
    356
    Likes Received:
    14
    Trophy Points:
    0
    Occupation:
    Developer
    Location:
    NOIDA
    Really i hard work for it. I request to all, Just read it then you can have basic idea of PURIFY.
     
  3. debleena_doll2002

    debleena_doll2002 New Member

    Joined:
    Feb 5, 2008
    Messages:
    119
    Likes Received:
    0
    Trophy Points:
    0
    Strange!!! Really nice way to detect memory leak in an application.
     
  4. ron_genum

    ron_genum New Member

    Joined:
    Feb 19, 2008
    Messages:
    21
    Likes Received:
    0
    Trophy Points:
    0
    Occupation:
    IT Personnel
    Location:
    Philippines
    just wana ask what type og programing language should i use for that sample program?
     
  5. asadullah.ansari

    asadullah.ansari TechCake

    Joined:
    Jan 9, 2008
    Messages:
    356
    Likes Received:
    14
    Trophy Points:
    0
    Occupation:
    Developer
    Location:
    NOIDA
    u can use "C or C++"
     
  6. ron_genum

    ron_genum New Member

    Joined:
    Feb 19, 2008
    Messages:
    21
    Likes Received:
    0
    Trophy Points:
    0
    Occupation:
    IT Personnel
    Location:
    Philippines
    great i got some idea bout using c++ but what i wanna know also is what does this memory leak is? does it have something to do would system errors? or slow file retrieval?
     
  7. asadullah.ansari

    asadullah.ansari TechCake

    Joined:
    Jan 9, 2008
    Messages:
    356
    Likes Received:
    14
    Trophy Points:
    0
    Occupation:
    Developer
    Location:
    NOIDA
    you can read detail from somewhere about memory leak...

    Memory leak occurs in your program when you are allocating memory dynamically(this memory is allocated on heap by operating system when you are calling malloc or calloc in C) and you forget to deallocate that memory. Now this memory will be called as "memory leak" .
    Example:

    int main()
    {
    int *p1 = (int *)malloc(10);
    }
    If your program will go out of scope of integer pointer p1 then memory allocated by pointer p1 will be leak. because you did'nt call free(p1) function.
     
  8. debleena_doll2002

    debleena_doll2002 New Member

    Joined:
    Feb 5, 2008
    Messages:
    119
    Likes Received:
    0
    Trophy Points:
    0
    You can search on google. Memory leaks related things you can get anywhere. You are asking very basic question.
     
  9. aisha.ansari84

    aisha.ansari84 New Member

    Joined:
    Feb 13, 2008
    Messages:
    82
    Likes Received:
    1
    Trophy Points:
    0
    can you please give me some more details about memory leak
     
  10. aisha.ansari84

    aisha.ansari84 New Member

    Joined:
    Feb 13, 2008
    Messages:
    82
    Likes Received:
    1
    Trophy Points:
    0
    suppose there is a function which allocates memory for a temporary variable temp , does some work and then returns temp.

    i think there should be a memory leak in this case as i cannot free temp ,right so how can i control memory leak here
     
  11. asadullah.ansari

    asadullah.ansari TechCake

    Joined:
    Jan 9, 2008
    Messages:
    356
    Likes Received:
    14
    Trophy Points:
    0
    Occupation:
    Developer
    Location:
    NOIDA
    I think this example will solved your problem.
    Code:
    #include<malloc.h>
    
    int* fun();
    int main()
    {
      int *p2 = fun();
      free(p2);
       return 0;
     }
    
    int* fun()
    {
      int *p1 = (int *)malloc(10);
      return p1;
    }
     
    Last edited by a moderator: Mar 6, 2008
  12. asadullah.ansari

    asadullah.ansari TechCake

    Joined:
    Jan 9, 2008
    Messages:
    356
    Likes Received:
    14
    Trophy Points:
    0
    Occupation:
    Developer
    Location:
    NOIDA
    to check memory leak, you can use my program as
    Code:
    #include<malloc.h>
    #include "findLeak.h"
    
    
    int* fun();
    int main()
    {
      int *p2 = fun();
      free(p2);
      WriteMemLeak();
      return 0;
     }
    
    int* fun()
    {
      int *p1 = (int *)malloc(10);
      return p1;
    
    }
     
    Last edited by a moderator: Mar 6, 2008
  13. aisha.ansari84

    aisha.ansari84 New Member

    Joined:
    Feb 13, 2008
    Messages:
    82
    Likes Received:
    1
    Trophy Points:
    0
    that means you want to say that i need to free the memory in the function where i m receiving the value returned by temporary variable.
     
  14. aisha.ansari84

    aisha.ansari84 New Member

    Joined:
    Feb 13, 2008
    Messages:
    82
    Likes Received:
    1
    Trophy Points:
    0
    understood and clear
     
    shabbir likes this.
  15. alramesh

    alramesh New Member

    Joined:
    Feb 5, 2008
    Messages:
    22
    Likes Received:
    0
    Trophy Points:
    0
    I run this program for my application. It's working. Too Cooooooooool.
    Thanks asadullah.ansari
     
  16. flyingfor

    flyingfor New Member

    Joined:
    Feb 6, 2008
    Messages:
    10
    Likes Received:
    0
    Trophy Points:
    0
    Excellent asadullah.ansari. I cannt imagine. I am very happy to see this memory leak detector program so simple and understandable.
     
  17. flyingfor

    flyingfor New Member

    Joined:
    Feb 6, 2008
    Messages:
    10
    Likes Received:
    0
    Trophy Points:
    0
    Can you tell me in different languages how to use this program?
     
  18. ron_genum

    ron_genum New Member

    Joined:
    Feb 19, 2008
    Messages:
    21
    Likes Received:
    0
    Trophy Points:
    0
    Occupation:
    IT Personnel
    Location:
    Philippines
    suppose ive detected memory leaks on my OS as I run that program, what will I do next?
    Is there any posible ways to prevent it or get rid of it?
     
  19. asadullah.ansari

    asadullah.ansari TechCake

    Joined:
    Jan 9, 2008
    Messages:
    356
    Likes Received:
    14
    Trophy Points:
    0
    Occupation:
    Developer
    Location:
    NOIDA
    You can make my program in binary also.

    Beauty of this program is that only one interface you have to use, that is "WriteMemLeak()" only.
    If any way other languages support to use C Interface, then you can use it.
     
    Last edited: Mar 6, 2008
  20. asadullah.ansari

    asadullah.ansari TechCake

    Joined:
    Jan 9, 2008
    Messages:
    356
    Likes Received:
    14
    Trophy Points:
    0
    Occupation:
    Developer
    Location:
    NOIDA
    I am not getting your question.

    Is it true what i am understanding that "memory leak is in OS not in your program".
    If it is true then your question is
    "How to detect memory leak coming in OS by program posted by asadullah.ansari? "

    Response me?
     
    shabbir likes this.

Share This Page