12 Mar
2023
12 Mar
'23
4:44 p.m.
Hi Ted,
...
> > cmd = aprintf("gdb -batch -ex
backtrace '%s/bk' %u 1>&%d 2>&%d",
> > bin, getpid(), fileno(f), fileno(f));
...
It works
surprisingly often, i.e. the process is healthy enough to
run system(3).
On Linux (or some other system using glibc) a limited facility is
built into the C library. So you can just do somthing like this:
frames = backtrace(stack_syms, 32);
backtrace_symbols_fd(stack_syms, frames, 2);
Since ’99, yes. :-) backtrace(3) says glibc 2.1 added it.
I use this for the fsck for ext4, and the nice thing
is that even with
a stripped binary.
For example:
Yes, that is nice.
Thanks, I've made a note.
Do you ever find things are so messed up that stdio has trouble whereas
using write(2) with compile-time memory allocations for a buffer would
have a better chance of reaching the TTY?
--
Cheers, Ralph.