Customizing the tracer

[Reza Ghanbari]

Hi, I am trying to implement a tracer that in addition to the memory tracer logs the memory ranges allocated by malloc/new. I was wondering if I can use drmemtrace for that purpose and add malloc/new tracing functionality on top of that.

I have tried implementing the new tracer as described here but I get compile errors saying the client cannot find the definition of  drmemtrace_client_main() symbol. Here is the minial source code and CMakeLists.txt content that I am using:

client.cpp:

#include "dr_api.h"

#include "drmemtrace/drmemtrace.h"

 

DR_EXPORT void

dr_client_main(client_id_t id, int argc, const char *argv[])

{

    dynamorio::drmemtrace::drmemtrace_client_main(id, argc, argv);

}

and CMakeLists.txt:

cmake_minimum_required(VERSION 3.22)

project(MemoryTracerClient)

set(DynamoRIO_DIR "${CMAKE_CURRENT_SOURCE_DIR}/dynamorio/install/cmake")

set(CMAKE_CXX_FLAGS  "${CMAKE_CXX_FLAGS} -g")

find_package(DynamoRIO)

if (NOT DynamoRIO_FOUND)

  message(FATAL_ERROR "DynamoRIO package required to build")

endif(NOT DynamoRIO_FOUND)

configure_DynamoRIO_global(ON ON)

set(name "memtrace_client")

function (add_client name source_file_list extension_list)

link_directories("${CMAKE_CURRENT_SOURCE_DIR}/dynamorio/install/tools/lib64/release")

  use_DynamoRIO_drmemtrace_tracer(${name})

  add_library(${name} SHARED ${source_file_list})

  configure_DynamoRIO_client(${name})

  foreach (ext ${extension_list})

    use_DynamoRIO_extension(${name} ${ext})

  endforeach (ext)

endfunction (add_client)

dd_client(memtrace_client "client.cpp" "")

[Enrico Deiana]

It looks like what you're trying to achieve can be done by the (already present) function tracing feature in DynamoRIO's tracer, which allows you to record arguments and return values of functions (you can deduce the memory ranges from that).

See: https://dynamorio.org/sec_drcachesim_funcs.html

Also, there is already a utility flag: `-record_heap` that conveniently records functions related to heap allocations (not just malloc/new), which can be further controlled via `-record_heap_value` (more info on those options at: https://dynamorio.org/sec_drcachesim_ops.html).

Then you'd only need a custom trace analyzer tool to extract and compose whatever information you need.

If you think you still need to build your custom tracer, please post the full error you're getting.

- Enrico

[Reza Ghanbari]

Hi Enrico, Thank you for your help and your suggestions about the func_view and function tracing, I have looked into it but unfortunately it does not provide all the information I need;
Here is the error that I get (by the way it is actually a run-time error not a compile-time one):

Error: Something went wrong!
<ERROR: using undefined symbol!>

running with gdb it says that the  drmemtrace_client_main() symbol is undefined.

Also, here is the script I use to run the tool:

LIB_BUILD=/PATH-TO-CMAKE-FILE/build

cmake -B $LIB_BUILD

cd $LIB_BUILD

make

cd ..

./dynamorio/build/bin64/drrun -c $LIB_BUILD/libmemtrace_client.so -- ./test/test_prog

the 'test_prog' could be anything, in my case it is a simple HelloWorld C code.

[Derek Bruening]

Please see the documentation which provides command lines for running the drmemtrace tracer.

Generally offline mode is recommended to allow repeated analyses, so from https://dynamorio.org/sec_drcachesim_offline.html you would run:

$ bin64/drrun -t drmemtrace -offline -record_heap -- ./test/test_prog

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