>On 2021-02-04, Anindya Mukherjee <anindy...@hotmail.com> wrote: >> I'm trying to debug the systat utility for learning purposes. I >> enabled >> -g -O0 in the Makefile, and built it in /usr/src/usr.bin/systat. It >> builds and runs fine. However, gdb cannot insert any breakspoints. I'm >> on a very recent snapshot and everything is fully patched. > >> [Switching to thread 588561] >> 0x00000b5f3d6c5c8a in ?? () >> (gdb) b engine.c:1156 >> Breakpoint 1 at 0x13aca: file engine.c, line 1156. >> (gdb) info b >> Num Type Disp Enb Address What >> 1 breakpoint keep y 0x0000000000013aca in message_set at >> engine.c:1156 > >OpenBSD binaries are PIE by default. The low address is before >relocation, you will see a similar address if you use "gdb systat" and >set a breakpoint before running, but in that case it is updated when >the process starts.
Thanks for reminding me about PIE! That explains everything. > >I'm not sure how to workaround this when attaching to a running process. It's not a big issue. I can start the program from within gdb. That works perfectly. > >(It doesn't directly help with this but generally you will have better >luck with gdb from ports, the old one in base doesn't cope well with >recent compilers. pkg_add gdb and use the egdb binary). I am using egdb. I switched to the base version in my listing just to see if it made any difference. Good to know it is recommended by the developers, thanks. I was playing with systat, and trying to understand how it works. I added a feature which makes the help text persistent in interactive mode. I often have it running in a tmux pane and it's useful to have the help display stay up while switching views. I'll post it in a separate thread for comments. Anyway, in the course of this I have found a couple of memory leaks. I can easily make it leak 100s of KBs of memory by updating the display in a certain way. I'll start a new thread with a fix. Regards, Anindya
