Python plugins

At first, to be able to write a plugins in Python for radare2 you need to install r2lang plugin. If you're going to use Python 2, then use r2pm -i lang-python2, otherwise (and recommended) - install the Python 3 version: r2pm -i lang-python3. Note - in the following examples there are missing functions of the actual decoding for the sake of readability!

For this you need to do this:

  1. import r2lang and from r2lang import R (for constants)
  2. Make a function with 2 subfunctions - assemble and disassemble and returning plugin structure - for RAsm plugin

    def mycpu(a):
     def assemble(s):
         return [1, 2, 3, 4]
    
     def disassemble(memview, addr):
         try:
             opcode = get_opcode(memview) # https://docs.python.org/3/library/stdtypes.html#memoryview
             opstr = optbl[opcode][1]
             return [4, opstr]
         except:
             return [4, "unknown"]
    
  3. This structure should contain a pointers to these 2 functions - assemble and disassemble
    return {
            "name" : "mycpu",
            "arch" : "mycpu",
            "bits" : 32,
            "endian" : "little",
            "license" : "GPL",
            "desc" : "MYCPU disasm",
            "assemble" : assemble,
            "disassemble" : disassemble,
    }
  1. Make a function with 2 subfunctions - set_reg_profile and op and returning plugin structure - for RAnal plugin
def mycpu_anal(a):
       def set_reg_profile():
        profile = "=PC    pc\n" + \
        "=SP    sp\n" + \
        "gpr    r0    .32    0    0\n" + \
        "gpr    r1    .32    4    0\n" + \
        "gpr    r2    .32    8    0\n" + \
        "gpr    r3    .32    12    0\n" + \
        "gpr    r4    .32    16    0\n" + \
        "gpr    r5    .32    20    0\n" + \
        "gpr    sp    .32    24    0\n" + \
        "gpr    pc    .32    28    0\n"
        return profile

    def op(memview, pc):
        analop = {
            "type" : R.R_ANAL_OP_TYPE_NULL,
            "cycles" : 0,
            "stackop" : 0,
            "stackptr" : 0,
            "ptr" : -1,
            "jump" : -1,
            "addr" : 0,
            "eob" : False,
            "esil" : "",
        }
        try:
            opcode = get_opcode(memview) # https://docs.python.org/3/library/stdtypes.html#memoryview
            esilstr = optbl[opcode][2]
            if optbl[opcode][0] == "J": # it's jump
                analop["type"] = R.R_ANAL_OP_TYPE_JMP
                analop["jump"] = decode_jump(opcode, j_mask)
                esilstr = jump_esil(esilstr, opcode, j_mask)

        except:
            result = analop
        # Don't forget to return proper instruction size!
        return [4, result]
  1. This structure should contain a pointers to these 2 functions - set_reg_profile and op
    return {
            "name" : "mycpu",
            "arch" : "mycpu",
            "bits" : 32,
            "license" : "GPL",
            "desc" : "MYCPU anal",
            "esil" : 1,
            "set_reg_profile" : set_reg_profile,
            "op" : op,
    }
  1. Then register those using r2lang.plugin("asm") and r2lang.plugin("anal") respectively
print("Registering MYCPU disasm plugin...")
print(r2lang.plugin("asm", mycpu))
print("Registering MYCPU analysis plugin...")
print(r2lang.plugin("anal", mycpu_anal))

You can combine everything in one file and load it using -i option:

r2 -I mycpu.py some_file.bin

Or you can load it from the r2 shell: #!python mycpu.py

See also:

Implementing new format plugin in Python

Note - in the following examples there are missing functions of the actual decoding for the sake of readability!

For this you need to do this:

  1. import r2lang
  2. Make a function with subfunctions:

    • load
    • load_bytes
    • destroy
    • check_bytes
    • baddr
    • entries
    • sections
    • imports
    • relocs
    • binsym
    • info

    and returning plugin structure - for RAsm plugin

    def le_format(a):
     def load(binf):
         return [0]
    
     def check_bytes(buf):
         try:
             if buf[0] == 77 and buf[1] == 90:
                 lx_off, = struct.unpack("<I", buf[0x3c:0x40])
                 if buf[lx_off] == 76 and buf[lx_off+1] == 88:
                     return [1]
             return [0]
         except:
             return [0]
    

    and so on. Please be sure of the parameters for each function and format of returns. Note, that functions entries, sections, imports, relocs returns a list of special formed dictionaries - each with a different type. Other functions return just a list of numerical values, even if single element one. There is a special function, which returns information about the file - info:

     def info(binf):
         return [{
                 "type" : "le",
                 "bclass" : "le",
                 "rclass" : "le",
                 "os" : "OS/2",
                 "subsystem" : "CLI",
                 "machine" : "IBM",
                 "arch" : "x86",
                 "has_va" : 0,
                 "bits" : 32,
                 "big_endian" : 0,
                 "dbg_info" : 0,
                 }]
    
  3. This structure should contain a pointers to the most important functions like check_bytes, load and load_bytes, entries, relocs, imports.

    return {
            "name" : "le",
            "desc" : "OS/2 LE/LX format",
            "license" : "GPL",
            "load" : load,
            "load_bytes" : load_bytes,
            "destroy" : destroy,
            "check_bytes" : check_bytes,
            "baddr" : baddr,
            "entries" : entries,
            "sections" : sections,
            "imports" : imports,
            "symbols" : symbols,
            "relocs" : relocs,
            "binsym" : binsym,
            "info" : info,
    }
  1. Then you need to register it as a file format plugin:
print("Registering OS/2 LE/LX plugin...")
print(r2lang.plugin("bin", le_format))

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