tools/mangle-ret.pl

#!/usr/bin/perl

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### mangle-ret.pl
### for converting ret into jmp* in a .s file,
### to see impact of rsb on native apps (independent of DynamoRIO)
###
### author: Derek Bruening   August 2002
###

$usage = "Usage: $0 <file>\n";

if ($#ARGV < 0) {
    print $usage;
    exit 1;
}
$file = $ARGV[0];
$file =~ /(.*)\.s$/;
if ($1 eq "") {
    print "Error: input file must be .s file\n";
    exit 1;
}
$out = "$1.mangle.s";
open(FILE, "< $file") || die "Error: Couldn't open $file for input\n";
open(OUT, "> $out") || die "Error: Couldn't open $out for output\n";
$rets = 0;
while (<FILE>) {
    if ($_ =~ /^\s*ret\s*$/) {
        $rets++;
        print OUT "# ---- translation of ret -----\n";
        print OUT "        addl \$4,%esp\n";
        print OUT "        jmp *0xfffffffc(%esp)\n";
    } elsif ($_ =~ /^\s*ret\s+\$([0-9a-fA-Fx]+)\s*$/) {
        print "Found ret with immed operand: $_";
        # extra stack space is removed after return address is popped
        $rets++;
        $extra = $1;
        if ($extra =~ /0x([0-9a-fA-F]+)/) {
            $remove = 4 + hex($1);
        } else {
            $remove = 4 + $extra;
        }
        $offs = -$remove;
        print  OUT "# ---- translation of ret -----\n";
        print  OUT "        addl \$$remove,%esp\n";
        printf OUT "        jmp *0x%08x(%%esp)\n", $offs;
    } elsif ($_ =~ /^\s*ret\s+/) {
        print "Error: Found unidentified ret: $_";
    } else {
        print OUT $_;
    }
}
close(FILE);
print "Translated $rets returns in $file to $out\n";