README.md

Converts asm to pseudo-C code.

Software Requirements

Requires radare2

Install

Follow the following steps to install r2dec via r2pm

Install using r2pm:

# initialize the r2pm database
$ r2pm -U
# install r2dec via r2pm
$ r2pm -i r2dec

Manual build & install:

• clone this repository
• Run meson setup build to create the build folder
• Run ninja -C build install to build the shared library and to install it

Usage

• Open your file with radare2
• Analyze the function you want to disassemble (af)
• Run the plugin via pdd

Arguments

[0x00000000]> pdd?
Usage: pdd [args] - core plugin for r2dec
 pdd           - decompile current function
 pdd?          - show this help
 pdd*          - the decompiled code is returned to r2 as comment (via CCu)
 pdda          - decompile current function side by side with assembly
 pddb          - decompile current function but shows only scopes
 pddo          - decompile current function side by side with offsets
 pddu          - install/upgrade r2dec via r2pm
 pdds <branch> - switches r2dec branch
 pddi          - generates the issue data

Environment
 R2DEC_HOME  defaults to the root directory of the r2dec repo

[0x00000000]> pdd --help

r2dec [options]
       --help       | this help message
       --assembly   | shows pseudo next to the assembly
       --blocks     | shows only scopes blocks
       --casts      | shows all casts in the pseudo code
       --colors     | enables syntax colors
       --debug      | do not catch exceptions
       --html       | outputs html data instead of text
       --issue      | generates the json used for the test suite
       --offsets    | shows pseudo next to the assembly offset
       --paddr      | all xrefs uses physical addresses instead of virtual addresses
       --xrefs      | shows also instruction xrefs in the pseudo code
       --as-comment | the decompiled code is returned to r2 as comment (via CCu)
       --as-opcode  | the decompiled code is returned to r2 as opcode (via aho)

Radare2 Evaluable vars

You can use these in your .radare2rc file.

r2dec.asm           | if true, shows pseudo next to the assembly.
r2dec.blocks        | if true, shows only scopes blocks.
r2dec.casts         | if false, hides all casts in the pseudo code.
r2dec.debug         | do not catch exceptions in r2dec.
r2dec.paddr         | if true, all xrefs uses physical addresses compare.
r2dec.slow          | if true load all the data before to avoid multirequests to r2.
r2dec.theme         | defines the color theme to be used on r2dec.
r2dec.xrefs         | if true, shows all xrefs in the pseudo code.
e scr.html          | outputs html data instead of text.
e scr.color         | enables syntax colors.

Report an Issue

• Open your file with radare2
• Analyze the function you want to disassemble (af)
• Give the data to the plugin via pddi or pdd --issue
• Insert the JSON returned by the previous command into the issue (you can also upload the output)

Supported Arch

6502 (experimental)
8051 (experimental)
arm 16/32/64 bit
avr
dalvik
m68k (experimental)
mips
ppc 32/64 bit (VLE included)
superh (experimental)
sparc
v850
wasm (experimental)
x86/x64

Developing on r2dec

Read DEVELOPERS.md

Example

This example shows a possible dump of the plugin.

Source Code

#include <stdio.h>

int main(int argc, char const *argv[]) {
    int var = 0;
    while(var < 0x90) {
        if(var < 0x10) {
            var += 0x50;
        }
        var += 0x10;
    }
    return 0;
}

radare2 view

╭ (fcn) main 50
│   main (int arg1, int arg2);
│           ; var int local_20h @ rbp-0x20
│           ; var int local_14h @ rbp-0x14
│           ; var signed int local_4h @ rbp-0x4
│           ; DATA XREF from entry0 (0x1041)
│           0x00001119      55             push rbp
│           0x0000111a      4889e5         mov rbp, rsp
│           0x0000111d      897dec         mov dword [local_14h], edi  ; arg1
│           0x00001120      488975e0       mov qword [local_20h], rsi  ; arg2
│           0x00001124      c745fc000000.  mov dword [local_4h], 0
│       ╭─< 0x0000112b      eb0e           jmp 0x113b
│       │   ; CODE XREF from main (0x1142)
│      ╭──> 0x0000112d      837dfc0f       cmp dword [local_4h], 0xf   ; [0xf:4]=0x3e000300
│     ╭───< 0x00001131      7f04           jg 0x1137
│     │⋮│   0x00001133      8345fc50       add dword [local_4h], 0x50  ; 'P'
│     │⋮│   ; CODE XREF from main (0x1131)
│     ╰───> 0x00001137      8345fc10       add dword [local_4h], 0x10
│      ⋮│   ; CODE XREF from main (0x112b)
│      ⋮╰─> 0x0000113b      817dfc8f0000.  cmp dword [local_4h], 0x8f  ; [0x8f:4]=0x2a800
│      ╰──< 0x00001142      7ee9           jle 0x112d
│           0x00001144      b800000000     mov eax, 0
│           0x00001149      5d             pop rbp
╰           0x0000114a      c3             ret

r2dec pseudo-C code

/* r2dec pseudo C output */
#include <stdint.h>
 
int32_t main (int32_t argc, char ** argv) {
    char ** local_20h;
    int32_t local_14h;
    int32_t local_4h;
    local_14h = edi;
    local_20h = rsi;
    local_4h = 0;
    while (local_4h <= 0x8f) {
        if (local_4h <= 0xf) {
            local_4h += 0x50;
        }
        local_4h += 0x10;
    }
    eax = 0;
    return eax;
}