rizin/doc/debug-internals.md
Riccardo Schirone 6f40dfe493
Move remaining things from shlr/ to meson subprojects (#2126)
* Move binrz meson directives to binrz/ dir

* Move rizin-shell-parser to a subproject

* Move bochs to a meson subproject

* Move rzqnx to meson subproject

* Move winkd to a meson subproject

* Move rzar to a meson subproject

* Move rzw32dbg_wrap to a meson subproject

* Move ptrace-wrap to a meson subproject

* Move rzgdb to a meson subproject

* Rename w32dbg_wrap to rzw32dbg_wrap

* Update CODEOWNERS

* Remove old references to shlr

* Move shlr/heap stuff in core and remove shlr/arm

* Move spp to a meson subproject

* Remove last references to shlr

* Remove use_webui option

* Move include files directives to librz/include/meson.build

* Move librz meson directives into librz/meson.build

* Handle d/ directories inside the specific module meson.build

* Move plugins listing to specific module meson.build

* Move rzheap to its own subproject

* Fix js linter and licenses

* Use meson.override_dependency for all rz_ modules
2021-12-22 09:20:39 +08:00

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Markdown

# Rizin Debugger Internals
The debugger is designed using a multi-tiered plug-in architecture that allows
overriding functionality for architecture or platform-specific reasons.
The bulk of the debugger functionality within Rizin core is split between the
"io", "reg", "bp", and "debug". More information on the specific files within
the tree follows.
## librz/include/r_debug.h
This is the main header file for the debugger. It defines all the relevant
structures and top-level functions, APIs, etc. The debugger plug-in API is also
defined in here.
## librz/io/p/io_debug.c
In order to interface with Rizin IO, a plug-in is provided. This handles, for
example, spawning processes under a debugger.
## librz/reg
The "reg" module provides functionality for reading and writing registers as
well as setting up profiles. (??profiles??)
The functionality lives in the following files:
(?? why so many files? can this be simplified??)
librz/reg/arena.c // ?? used by analysis and debugger
librz/reg/cond.c // condition registers
librz/reg/double.c // support for double-precision floating point numbers
librz/reg/profile.c // ?? used by analysis and debugger
librz/reg/reg.c // top-level register specific code (all of rizin)
librz/reg/value.c // dealing with register values
librz/reg/t/p.c // test code for printing general-purpose registers
librz/reg/t/regdiff.c // ?? test code for?
librz/reg/t/test.c // test code for register handling
## librz/bp
The "bp" subsystem of Rizin implements all the necessary details for dealing
with breakpoints on any given architecture. It handles managing the list of
breakpoints and more.
Rizin supports a multitude of different types of breakpoints.
(`??` is there a list? sw, hw, and trace? anything else??)
librz/bp/bp.c // main breakpoint management code
librz/bp/io.c // setting and resetting(??) breakpoints
librz/bp/parser.h // header for breakpoint parser (??)
librz/bp/parser.c // code for breakpoint parser (??)
librz/bp/plugin.c // breakpoint plugin management
librz/bp/traptrace.c // traptrace (??)
librz/bp/watch.c // watch points (mostly not implemented)
For architecture specific-handling, "bp" delegates various functionality to
plugins. The interface for these plugins is much simpler than other plugins
used in the Rizin debugger -- they only define which byte sequences represent
valid breakpoints for a given architecture.
librz/bp/p/bp_arm.c // ARM64, ARM, Thumb, Thumb-2 (big/little endians)
librz/bp/p/bp_bf.c // Brainfuck!
librz/bp/p/bp_mips.c // MIPS, big/little endian
librz/bp/p/bp_ppc.c // PowerPC, big/little endian
librz/bp/p/bp_sh.c // SuperH
librz/bp/p/bp_x86.c // int3...
## librz/debug/debug.c
The main top-level debugger functionality lives here. It aims to abstract away
the common code flow and integration into Rizin while delegating more nuanced
system interactions to plug-ins.
librz/debug/arg.c // used by the analysis engine (??)
librz/debug/desc.c // code for handling file descriptors inside an inferior
librz/debug/esil.c // ESIL related debugging code (??)
librz/debug/map.c // top-level API for dealing with memory maps
librz/debug/pid.c // top-level API for dealing with processes
librz/debug/plugin.c // top-level debugger plugin API handling
librz/debug/reg.c // top-level code for register r/w and display
librz/debug/signal.c // top-level functions for signals
librz/debug/snap.c // code for saving, restoring, showing memory snapshots
librz/debug/trace.c // top-level tracing API (counting insn hits, etc)
librz/debug/t/main.c // test code for the debugger API
## librz/core/cmd_debug.c
Most of the time a debugger is used by a human to try to understand subtle
problems with software and/or hardware. That task would be very difficult
without a user interface of some kind. The CLI commands exposed to Rizin are
implemented in here. To get more information about this interface, consult the
user manual or try "d?" to get a crash course.
## Debugger Plug-Ins
As mentioned before, the platform specific debugger functionality is delegated
to back-end plugins that implement the necessary interactions, protocols, or
otherwise to get the job done. These plug-ins implement the rizin debugger
plug-in API defined in r_debug.h.
### librz/debug/p/debug_bf.c
A debugger plug-in capable of debugging brainfuck code!
librz/debug/p/bfvm.c // Brainfuck VM implementation
librz/debug/p/bfvm.h
### librz/debug/p/debug_bochs.c
A debugger plug-in that utilizes bochs emulator to control execution.
### librz/debug/p/debug_esil.c
This debugger plug-in enables debugging and tracing Rizin own intermediate
language, Evaluable Strings Intermediate Language (ESIL).
### librz/debug/p/debug_gdb.c
A Rizin debugger plug-in that uses a remote GDB server/stub as its backend. The
protocol parsing itself is located at subprojects/rzgdb. And corresponding IO
plugin is located in librz/io/p/io_gdb.c
### librz/debug/p/debug_native.c
The "native" debugger plug-in is a bit of a doozy. It implements functionality
for debugging on the most common platforms available: Windows, OSX, Linux, and
BSD. Much of the underlying debug API between these platforms are similar and
thus much of the code within this plug-in is shared. The parts that are not
shared are implemented by platform-specific functions that are provided in the
following files:
// architecture-specific debugger code
librz/debug/p/native/arm.c // unused?
// code for handling backtracing
librz/debug/p/native/bt.c
librz/debug/p/native/bt/fuzzy-all.c
librz/debug/p/native/bt/generic-x64.c
librz/debug/p/native/bt/generic-x86.c
// architecture-specific register handling
librz/debug/p/native/drx.c // x86-specific debug registers
librz/debug/p/native/reg.c // cute include of the files below
librz/debug/p/native/reg/kfbsd-x64.h
librz/debug/p/native/reg/kfbsd-x86.h
librz/debug/p/native/reg/netbsd-x64.h
librz/debug/p/native/reg/netbsd-x86.h
librz/debug/p/native/reg/windows-x64.h
librz/debug/p/native/reg/windows-x86.h
// platform-specific debugger code on Linux
librz/debug/p/native/linux/linux_debug.c // main linux-specific debugging code
librz/debug/p/native/linux/linux_debug.h // including cute penguin ascii art
// architecture-specific register handling on Linux (?? what is this format??)
librz/debug/p/native/linux/reg/linux-arm.h
librz/debug/p/native/linux/reg/linux-arm64.h
librz/debug/p/native/linux/reg/linux-mips.h
librz/debug/p/native/linux/reg/linux-ppc.h
librz/debug/p/native/linux/reg/linux-x64.h
librz/debug/p/native/linux/reg/linux-x64-32.h
librz/debug/p/native/linux/reg/linux-x86.h
// platform-specific debugger code on Windows
librz/debug/p/native/w32.c // !! not used by anything else
librz/debug/p/native/maps/windows.c // platform-specific memory map handling
librz/debug/p/native/windows/windows_debug.c // main code for win32 debugger plugin
librz/debug/p/native/windows/windows_debug.h // including cute windows ascii art
// platform-specific debugger code on XNU (OSX/iOS/etc)
librz/debug/p/native/darwin.c // !! not used by anything else
librz/debug/p/native/maps/darwin.c // platform-specific memory map handling
librz/debug/p/native/xnu/xnu_debug.c // main XNU-specific debugging code
librz/debug/p/native/xnu/xnu_debug.h // including cute apple ascii art
librz/debug/p/native/xnu/trap_arm.c // ARM family hardware bps (??)
librz/debug/p/native/xnu/trap_x86.c // x86 family hardware bps (??)
librz/debug/p/native/xnu/xnu_excthreads.c // additional XNU thread handling
librz/debug/p/native/xnu/xnu_threads.c // XNU thread and register handling
librz/debug/p/native/xnu/xnu_threads.h
// architecture-specific register handling on XNU (?? what is this format??)
librz/debug/p/native/xnu/reg/darwin-x86.h
librz/debug/p/native/xnu/reg/darwin-arm.h
librz/debug/p/native/xnu/reg/darwin-ppc.h
librz/debug/p/native/xnu/reg/darwin-arm64.h
librz/debug/p/native/xnu/reg/darwin-x64.h
// platform-specific debugger code on BSD
librz/debug/p/native/bsd/bsd_debug.c // main BSD debugging code
librz/debug/p/native/bsd/bsd_debug.h
### librz/debug/p/debug_qnx.c
A debugger plug-in that enables debugging code natively on QNX systems. Corresponding
IO plugin is located in librz/io/p/io_qnx.c
See doc/qnx
### librz/debug/p/debug_rap.c
See doc/rap
### librz/debug/p/debug_winkd.c
A debugger plugin that enables debugging code remotely via WinDbg protocol.
WinDbg protocol parser is located in subprojects/rzwinkd. Corresponding IO
plugin located in librz/io/p/io_winkd.c See doc/winkd.
## Conclusion
Best of luck!