Build failure in release configuration due to -Werror=stringop-truncation errors

[edeiana]

Build errors occur when compiling DynamoRIO in release mode using gcc 14.2.0 and g++ 13.3.0 on Ubuntu 24.04.
These errors are specifically related to the -Werror=stringop-truncation warning, indicating potential string truncation issues due to the specified bounds depending on the source argument's length. Some are false positives, others seem to highlight genuine potential problems within the code.

The following commands were used to configure and build DynamoRIO:

cmake -DBUILD_TESTS=ON -DCMAKE_C_COMPILER=$(which gcc) -DCMAKE_CXX_COMPILER=$(which g++) -B build -S $(pwd)
make -C build -j10

Note:
Building tests with -DBUILD_TESTS=ON generates additional stringop-truncation errors, some of which are likely false positives.

[Flandini]

What version of DynamoRIO are you using? latest master
Does the latest build from https://github.com/DynamoRIO/dynamorio/releases solve the problem? no
What operating system version are you running on? ("Windows 10" is not sufficient: give the release number.) see above
Is your application 32-bit or 64-bit? N/A

[Flandini]

I configure and make dynamorio as:

cmake -DBUILD_TESTS=ON -DCMAKE_C_COMPILER=$(which gcc) -DCMAKE_CXX_COMPILER=$(which g++) -B build -S $(pwd)
make -C build -j10

[derekbruening]

These stringop warnings are disabled in core/:

$ git grep -n stringop-truncation
CMakeLists.txt:920:    CHECK_C_COMPILER_FLAG("-Wstringop-truncation" stringop_truncation_avail)
CMakeLists.txt:922:      set(WARN "${WARN} -Wno-stringop-truncation")

[Flandini]

Looks like I foobar'd my cmake build directory. I generated a compile_commands.json for use with my editor, and it is missing these warn disables and some other ones for the files in this accompanying PR. Rebuilding with a fresh cmake build directory, I don't have these errors anymore and things compile fine.

Happy to close the accompanying PR as user error, or fix up the truncation warning problem and revert the other changes, whichever y'all want.

[derekbruening]

The issue of strncpy wasting time padding the entire buffer with nulls is also covered here. Since we use the dr_snprintf BUFFER_SIZE_ELEMENTS;NULL_TERMINATE_BUFFER pattern for construction in many places, and there is no simple strncpy replacement, we are considering replacing strncpy when the buffer is often larger than the source with dr_snprintf %s.