Debugging applications

The toolchain includes a gdb that can be used for remote debugging applications on the terminal.

Installing Debugger

There is no need to install additional software beside the VOS3 toolchain. The GNU debugger is located in the toolchain as bin/arm-none-linux-gnueabihf-gdb

user> bin/arm-none-linux-gnueabihf-gdb --version
GNU gdb (GNU Toolchain for the Arm Architecture 11.2-2022.02 (arm-11.14)) 11.2.90.20220202-git
Copyright (C) 2022 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

Using Debugger

For remote debugging to work, gdbserver needs to be started on the terminal.

$> gdbserver :22222 mybinary
Process /home/usr1/mybinary created; pid = 1137
Listening on port 22222

To attach to an already running process also gdbserver can be instrumented. To allow attaching to a process, this feature needs to be enabled first as root user.

#> echo 0 > /proc/sys/kernel/yama/ptrace_scope
$> gdbserver :22222 --attach $(pidof mybinary)
Attached; pid = 1162
Listening on port 22222

From the developers PC gdb can now be configured to connect to this gdbserver instance.

user> /opt/vos3/bin/arm-none-linux-gnueabihf-gdb -q mybinary-debug
Reading symbols from mybinary-debug...
(gdb) target remote <terminal-ip-here>:22222
Remote debugging using <terminal-ip-here>:22222
Reading symbols from /opt/vos3/arm-none-linux-gnueabihf/libc/lib/ld-linux-armhf.so.3...
0xb6fdd8d4 in ?? () from /opt/vos3/arm-none-linux-gnueabihf/libc/lib/ld-linux-armhf.so.3
(gdb) b main
Breakpoint 1 at 0x11d2a: file main.cpp, line 5.
(gdb) c
Continuing.
Breakpoint 1, main (argc=1, argv=0xbefffe84) at main.cpp:5
5 int main(int argc, char **argv) {