mdam (Monitoring Dynamically Allocated Memory)

About

'mdam' is tool monitoring dynamically allocated memory. If you load 'mdam.so' with LD_PRELOAD, you can find memory leak in C language program compiled with gcc.

Build

Please clone this repository and execute the following command.

$ cd mdam
$ make

If make is succeed, a shared library nemed 'mdam.so' is created.

Usage

1. Execute program with mdam.so

Please configure mdam.so to LD_PRELOAD and execute program which you want to monitor memory leak.

$ LD_PRELOAD=mdam.so <executable file>

2. Finish program and display result

When the program finishes, the result memory leak detection result is displayed.

If memory leak is not detected, like following message is displayed.

Any memory leak is not detected !

Otherwise, like following message is displayed.

----------------------------------------------------------
Address           Size (byte)   Return address    Caller
----------------------------------------------------------
0x5596930c3260    15            0x5596916d38fc    main
0x5596930c32d0    30            0x5596916d390a    main
0x5596930c34b0    512           0x5596916d3932    main
0x5596930c36e0    552           0x7efe7f956e4a    fopen

The meaning of each item is follwing.

Item	Description
Address	Address of leaked memory.
Size (byte)	Byte size of leaked memory.
Return address	Address of instruction which occured memory leak.
Caller	Name of function which allocate the leaked memory.

Notice : 'Caller' is displayed correctly only when target program is compiled with '-rdynamic' option. Otherwise displayed '(none)'

3. Change the output destination

By default, the memory leak detection result is displayed console. But if you set file path to 'MDAM_LOG', mdam is writes the result to the specified file.

For example, set "leak.log" to MDAM_LOG.

$ MDAM_LOG=leak.log LD_PRELOAD=mdam.so <executable file>

The memory leak detection result is written in 'leak.log'.

$ cat leak.log
----------------------------------------------------------
Address           Size (byte)   Return address    Caller
----------------------------------------------------------
0x5596930c3260    15            0x5596916d38fc    main
0x5596930c32d0    30            0x5596916d390a    main
0x5596930c34b0    512           0x5596916d3932    main
0x5596930c36e0    552           0x7efe7f956e4a    fopen