A LD_PRELOAD override that causes normal process termination to instead
result in abnormal process termination through a raised SIGABRT signal via
abort(3) (even if SIGABRT is ignored, or is caught by a handler that returns).
The override works by splicing in a "fake main" function to be executed instead
of the program main function. The fake_main function registers abort(3) as
an atexit(3) handler to be called at normal process termination.
LD_PRELOAD cannot be used to override main directly as it can only override
functions in dynamically linked shared libraries whose addresses are determined
via the Procedure Linkage Table (PLT). However, main's location is not
determined via the PLT, but is statically linked to the executable entry routine
at __start which pushes main's address onto the stack, then invokes libc's
startup routine, which obtains main's address from the stack.
Instead, the override uses LD_PRELOAD to override libc's startup routine,
__libc_start_main, which is normally responsible for calling main and splice
in fake_main there. We can't just run our setup code in the overriden
__libc_start_main directly because the real __libc_start_main is responsible
for setting up the C runtime environment, so we can't rely on standard library
functions such as malloc(3) or atexit(3) being available yet.
Building:
make
Usage:
LD_PRELOAD=abort_at_exit.o program
Loosely based on libminijailpreload.c by the Chromium OS Authors.
Use of this source code is governed by a BSD-style license that can be found in the LICENSE file.