Connecting r2 with gdb

Running gdbserver

$ gdbserver :2345 /bin/ls
(gdb) target remote localhost:2345

Connecting from r2

$ r2 -D gdb gdb://127.0.0.1:2345

Supported implementations

r2 have support for connecting to remote GDB instances:

            x86-32   x86-64   arm    arm64   sh
winedbg       x        x       -      -      -
qemu          x        x       ?      x      -
gdbserver     x        x       ?      ?      ?

x = supported
? = untested
- = not supported

Supported Commands

• read/write memory

  Writing or reading memory is implemented through the m/M packet.

• read registers

  Reading registers is currently implemented through the <g> packet of the gdb protocol. It returns the whole register profile at once.

• write registers

  There are two ways of writing registers. The first one is through the P packet. It works like this: P<register_index>=<register_value> The second one is the G packet, that writes the whole register Profile at once. The implementation first tries to use the newer P packet and if it receives a $00# packet (that says not implemented), it tries to write through the G packet.

• stepping (but this is still the softstep mode and for an unknown reason it sill does not call th gdb_write_register function)

Supported Packets:

• g : Reads the whole register Profile at once
• G : Writes the whole register Profile at once
• m : Reads memory
• M : Writes memory
• vCont,v : continues execution of the binary
• P : Write one register

TODO

• Implement GDBserver to allow other apps use r2 debugger
• Fix that usese the gdb internal stepping version
• Fix softstep, that it finally recoils correct (it just have to reset the eip/rip)
• Add Breakpoints (should be an easy add of the function, because its already implemented in the gdb lib)