objdump to C-string of opcodes

objdump-to-c-string.pl

#!/usr/bin/env perl

# SPDX-License-Identifier: CC0 OR 0BSD OR MIT OR Apache-2.0
# 2023 Andrei Listochkin

# Usage: objdump -d program | ./objdump-to-c-string.pl <address_ranges>
#        where <address_ranges> can be individual addresses or ranges 
#        (e.g., `1131-1137 114c 10d8 1171`)
#
# This script parses the output of 'objdump -d program' and generates formatted
# C-style string of opcodes for the specified address ranges. 
# The input from 'objdump' is read from standard input (stdin). 
# The script will extract the opcodes, instructions, and operands 
# for the specified addresses and ranges, and format them as C code. 
# The output preserves the order of addresses in the arguments. 
# You can specify the same address multiple times.
#
# Example:
# If the objdump output contains the following line:
#    1131:       48 89 e5                mov    %rsp,%rbp
# Running the script as follows:
#    objdump -d shellcode_asm | ./objdump-to-c-string.pl 1131-1137 10d8 1171
# Would generate the following output:
#    /*1131:*/ "\x48\x89\xe5" //mov %rsp,%rbp
#    /*1134:*/ "\x48\x31\xff" //xor %rdi,%rdi
#    /*1137:*/ "\x48\x31\xc0" //xor %rax,%rax
#    /*10d8:*/ "\xc3" //ret 
#    /*1171:*/ "\x2f\x73\x68" // 

use strict;
use warnings;

# Read the list of address ranges from command line arguments
my @address_ranges = @ARGV;

my %instructions;

# Loop through each line in the stdin
while (<STDIN>) {
    chomp;

    if (/^\s* # start of the line
            (?<address>[0-9a-f]+):
            \s*
            (?:(?<opcode>[0-9a-f ]+)\s*) # will grap all bites with spaces
            (?:(?<instruction>\w+)\s*)?
            (?<operands>.*)
            $/x) {
        my ($address, $opcode, $instruction, $operands) = (
                $+{'address'}, 
                $+{'opcode'}, 
                # instructions and operands are optional
                $+{'instruction'} // "", 
                $+{'operands'} // ""
        );
        push @{$instructions{hex($address)}}, {
            opcode => $opcode,
            instruction => $instruction,
            operands => $operands,
        };
    }
}

# Generate the C-code output for the given address ranges
foreach my $range (@address_ranges) {
    if ($range =~ /^(?<start>[0-9a-f]+)-(?<end>[0-9a-f]+)$/) {
        my ($start, $end) = ($+{'start'}, $+{'end'});
        foreach my $address (sort { $a <=> $b } keys %instructions) {
            if ($address >= hex($start) && $address <= hex($end)) {
                my $formatted_address = sprintf("%x", $address);
                print "/*$formatted_address:*/ ";
                foreach my $op (@{$instructions{$address}}) {
                    my $formatted_opcode = join('', map { "\\x$_" } split(' ', $op->{opcode}));
                    print "\"$formatted_opcode\" //$op->{instruction} $op->{operands}\n";
                }
            }
        }
    } elsif (exists $instructions{hex($range)}) {
        my $address = hex($range);
        my $formatted_address = sprintf("%x", $address);
        print "/*$formatted_address:*/ ";
        foreach my $op (@{$instructions{$address}}) {
            my $formatted_opcode = join('', map { "\\x$_" } split(' ', $op->{opcode}));
            print "\"$formatted_opcode\" //$op->{instruction} $op->{operands}\n";
        }
    }
}