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Dominik
227b69573d
Replace the glibc-only execinfo.h backtrace with _Unwind_Backtrace
from GCC's libgcc, which works on glibc and musl, static-pie and
dynamic, across all supported architectures.
Key design decisions:
- __ehdr_start (GNU ld linker symbol) gives the PIE load base
reliably on all targets, replacing dl_iterate_phdr which does not
enumerate the main executable consistently on musl static builds
- SOURCE_ROOT compile definition strips the build machine prefix so
backtraces show project-relative paths (src/signals.c:42)
- dladdr() resolves dynamic symbol names from .dynsym for stripped
shared-library frames; /proc/self/maps provides the library name
as fallback when no symbol is exported
- Each frame is logged as a single line:
#N func_name src/file.c:line (resolved)
#N 0xADDRESS (libc.so.6 sym+off) (unresolved)
New subcommands:
- crash: triggers a deterministic SIGSEGV via mmap(PROT_NONE)
(not UB, not elided by the optimizer, not caught by
sanitizers) to validate the crash handler end-to-end
- backtrace: prints a live backtrace without crashing, for manual
inspection on a given build or platform
CI: add check_crash() to test/arch_test.sh, called unconditionally
for every architecture to verify the handler fires and a backtrace
is produced.
Bug fixes:
- removePID(): guard config.files.pid.v.s != NULL before fopen()
to prevent a secondary SIGSEGV when config was never loaded
(e.g. crash/backtrace subcommands)
- signal_handler(): fflush(stdout) immediately after generate_backtrace()
so the output is preserved even if cleanup() faults on uninitialized
state before exit() can flush stdio
Signed-off-by: Dominik <dl6er@dl6er.de>