How to add debug flags to the avdecccmdline executable in Linux?

[JamesAdams2016]

Hi,

My avdecccmdline executable is crashing when built in Linux, due to no apparent
fault of the original code, I hasten to add; it was modified here to add a
startAVDECCController() function to use it as a DLL. When I build it in Linux,
it also crashes the same way when I build it as an SO, so I'm looking at it as
an executable using gdb. However, I haven't been able to get the debug flags
added when building, apparently.

I tried adding this line
add_compile_options(${CMAKE_CXX_FLAGS_DEBUG})
in \controller\app\cmdline\CMakeLists.txt
so that my UNIX elseif looked like this:
elseif(UNIX)
add_executable (avdecccmdline ${CMDLINE_INCLUDES} ${CMDLINE_SRC})
add_compile_options(${CMAKE_CXX_FLAGS_DEBUG})
set(PCAP_NAME pcap)
set(READLINE_NAME readline)
target_link_libraries(avdecccmdline rt)

I did: cmake .
and got
-- Configuring done
-- Generating done
-- Build files have been written to:
So the ${CMAKE_CXX_FLAGS_DEBUG} syntax seemed to work.

I built, using make -f Makefile.

I tried to gdb it:

/controller/app/cmdline# gdb ./avdecccmdline.exe
Reading symbols from ./avdecccmdline.exe...(no debugging symbols found)...done.
(gdb) start
Temporary breakpoint 1 at 0x694e2
Starting program: /controller/app/cmdline/avdecccmdline.exe
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
[New Thread 0x7ffff6513700 (LWP 3493)]
[New Thread 0x7ffff5d12700 (LWP 3494)]

Thread 1 "avdecccmdline.e" hit Temporary breakpoint 1, 0x00005555555bd4e2 in main ()
(gdb) step
Single stepping until exit from function main,
which has no line number information.

Thread 1 "avdecccmdline.e" received signal SIGSEGV, Segmentation fault.
_IO_new_fclose (fp=0x0) at iofclose.c:48
48 iofclose.c: No such file or directory.
(gdb)

The second line above says no debugging symbols found.
How can I add debug flags to the avdecccmdline executable in Linux?

Also if you have any idea what the problem is in the code, I sure would like to
know that. It works when built for Windows, but in Linux here, it gets this
SIGSEGV before reaching main().

I also tried making the add_compile_options() line like this:
add_compile_options(${CMAKE_CXX_FLAGS} ${CMAKE_CXX_FLAGS_DEBUG})
Redoing the above, I still got in the first line of gdb output:
Reading symbols from ./avdecccmdline.exe...(no debugging symbols found)...done.

Best regards,
-James

[JamesAdams2016]

I don't know why some lines in my post came out in bold and with a larger font size.

[JamesAdams2016]

I had found a note that debug flags had to be set in the link as well. I also
made the compile options literal, so that my elseif block is:
elseif(UNIX)
add_executable (avdecccmdline ${CMDLINE_INCLUDES} ${CMDLINE_SRC})
add_compile_options(-Wall -std=c++11 -O0 -g)
add_link_options(-debug)
set(PCAP_NAME pcap)
set(READLINE_NAME readline)
target_link_libraries(avdecccmdline rt)

I still got "(no debugging symbols found)", as above.

[andrew-elder]

Did you build the library with debug symbols turned on?

[JamesAdams2016]

I don't believe I was building the library with the debug symbols.
I added these two lines
add_compile_options(-Wall -std=c++11 -O0 -g)
add_link_options(-debug)
In
\controller\lib\CMakeLists.txt
So that my elseif(UNIX) near the end became:
elseif(UNIX)
add_compile_options(-Wall -std=c++11 -O0 -g)
add_link_options(-debug)
target_link_libraries(controller pcap)
target_link_libraries(controller pthread)
target_link_libraries(controller rt)

Using this the same way, I still got
Reading symbols from avdecccmdline...(no debugging symbols found)...done.
I always do "make -f Makefile clean" before doing "cmake ." .

[JamesAdams2016]

I tried modifying the CMakeLists.txt files the same way in my download from here
of Apr 24 2019 and also didn't get the debugging symbols.
However, it doesn't get a segfault or crash.

[JamesAdams2016]

I ran our crashing code through Valgrind ver 3.15.0 and got the following:

---

controller/app/cmdline# /snap/bin/valgrind ./avdecccmdline
==4369== Memcheck, a memory error detector
==4369== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==4369== Using Valgrind-3.15.0 and LibVEX; rerun with -h for copyright info
==4369== Command: ./avdecccmdline
==4369==
==4369== Invalid read of size 4
==4369== at 0x599C254: fclose@@GLIBC_2.2.5 (iofclose.c:48)
==4369== by 0x16ABDD: clearLogFile() (in controller/app/cmdline/avdecccmdline)
==4369== by 0x17153A: main (in controller/app/cmdline/avdecccmdline)
==4369== Address 0x0 is not stack'd, malloc'd or (recently) free'd
==4369==
==4369==
==4369== Process terminating with default action of signal 11 (SIGSEGV)
==4369== Access not within mapped region at address 0x0
==4369== at 0x599C254: fclose@@GLIBC_2.2.5 (iofclose.c:48)
==4369== by 0x16ABDD: clearLogFile() (in controller/app/cmdline/avdecccmdline)
==4369== by 0x17153A: main (in controller/app/cmdline/avdecccmdline)
==4369== If you believe this happened as a result of a stack
==4369== overflow in your program's main thread (unlikely but
==4369== possible), you can try to increase the size of the
==4369== main thread stack using the --main-stacksize= flag.
==4369== The main thread stack size used in this run was 8388608.
==4369==
==4369== HEAP SUMMARY:
==4369== in use at exit: 11,656 bytes in 8 blocks
==4369== total heap usage: 10 allocs, 2 frees, 84,912 bytes allocated
==4369==
==4369== LEAK SUMMARY:
==4369== definitely lost: 0 bytes in 0 blocks
==4369== indirectly lost: 0 bytes in 0 blocks
==4369== possibly lost: 576 bytes in 2 blocks
==4369== still reachable: 11,080 bytes in 6 blocks
==4369== suppressed: 0 bytes in 0 blocks
==4369== Rerun with --leak-check=full to see details of leaked memory
==4369==
==4369== For lists of detected and suppressed errors, rerun with: -s
==4369== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 0 from 0)
Segmentation fault (core dumped)

Is it trying to read four bytes at address 0x0? What would cause it to do that?

[JamesAdams2016]

Although I fixed the crashing in my version of AVDECC, it would still be nice to
know how to set the debug flags.
My version of AVDECC had some hard-coded Windows paths for file IO, and
selecting Linux paths got the code running.
Maybe someone can try adding debug flags sometime and let me know how. Maybe
make a wiki entry over at the wiki tab on how to do it.