What is this?

It may occasionally be hard to run failing program under debugger e.g. if it runs inside deeply nested build system or shell script.

This project solves this by providing a library (libdebugme.so) which can be linked or preloaded to top-level program to catch signals and automatically run gdb (or, in future, any other debugger).

The project is BSD-licensed. It has no fancy dependencies, just Glibc and GDB.

Usage

Disclaimer: I have not yet seriously tested this although it seems to work robustly on Ubuntu 14.04 and Fedora 22.

Simply preload libdebugme.so to process and ask it to intercept "bad" events:

DEBUGME_OPTIONS=handle_signals=1 LD_PRELOAD=libdebugme.so make

and it'll automatically run gdb on error. For particularly bad errors which overflow stack you may need to append ...:altstack=1 to DEBUGME_OPTIONS.

Alternatively you can dlopen libdebugme at runtime or explicitly link your app against it (but beware of --as-needed which is enabled by default in modern distros and will drop library dependency unless you call it explicitly). In these cases you'll need to initialize library explicitly via APIs from debugme.h (as DEBUGME_OPTIONS has not been set).

Available runtime options:

• xterm - run debugger in a separate xterm
• handle_signals - attach debugger on all bad signals (SIGSEGV, SIGABRT, SIGILL, etc.)
• debug - print diagnostic info
• debug_opts - additional options to pass to debugger. Note: the debugger command line, including those options is interpreted by $SHELL (typically your login shell).
• altstack - run signal handlers on alternative stack (needs handle_signals)

Future plans

Here're some plans for libdebugme:

• ensure thread and signal safety
• support other debuggers (ddd, lldb, Visual Studio, etc.)
• use CMake
• other minor TODO/FIXME are scattered all over the codebase