gdb

Startup Routine

Binary:

gdb binary / gdb --args <args...>
set args <args...> - set args if needed
break <where> - set breakpoints as necessary
r - run

Core dumps:

gdb binary core-dump

Paths

directory <dir / dir <dir>
- Add dir to the front of the source path
- Without dir argument resets path to $cdir:$cwd
set directories <path-list>
- Set the source path to path-list. $cdir:$cwd added if missing.
set substitute-path <from> <to>
- Substitution rule for finding source files
- With arguments, all substitution rules are deleted.
set solib-search-path <dir>
- Specifies directories where GDB will search for shared libraries with symbols. Very useful when debugging with gdbserver.

Symbols

set debug-file-directory <dir>
- Symbols files are loaded from dir as long as the binary supports debug-link and provides the names.
add-symbol-file filename address
- Parameter address is the address for .text section.
- Can be retrieved with: readelf -WS <filename> | grep .text | awk '{ print "0x"$5 }'

Quick Debug

bt - backtrace: show stack functions and args
info frame - show stack start/end/args/locals pointers
x/100x $sp - show stack memory

Resources