The code I'm looking at right now is a counter to track the number of users currently on a website. I downloaded it from a website, but they clearly state that it connects back to them. I'd rather learn from this code to rewrite my own counter for this purpose, but the code is a single string of obfuscated code.
$A36l105l112l32l61l32l36l69l78l86l123l39l82l69l77l79l84l69l95l65l68l68
+l82l39l125l59l36l116l105l109l101l32l61l32l116l105l109l101l59l36l102l1
+11l117l110l100l32l61l32l48l59l36l117l115l101l114l115l32l61l32l48l59l6
+4l112l97l105l114l115l32l61l32l115l112l108l10=q#36l105l112l32l61l32l36
+l69l78l86l123l39l82l69l77l79l84l69l95l65l68l68l82l39l125l59l36l116l10
+5l109l101l32l61l32l116l105l109l101l59l36l102l111l117l110l100l32l61l32
+l48l59l36l117l115l101l114l115l32l61l32l48l59l64l112l97l105l114l115l32
+l61l32l115l112l108l105l116l40l47l38l47l44l32l36l69l78l86l123l34l81l85
+l69l82l89l95l83l84l82l73l78l71l34l125l41l59l102l111l114l101l97l99l104
+l32l36l112l97l105l114l32l40l64l112l97l105l114l115l41l32l123l40l36l110
+l97l109l101l44l32l36l118l97l108l117l101l41l32l61l32l115l112l108l105l1
+16l40l47l61l47l44l32l36l112l97l105l114l41l59l36l118l97l108l117l101l32
+l61l126l32l116l114l47l43l47l32l47l59l36l118l97l108l117l101l32l61l126l
+32l115l47l37l40l91l97l45l102l65l45l70l48l45l57l93l91l97l45l102l65l45l
+70l48l45l57l93l41l47l112l97l99l107l40l34l67l34l44l32l104l101l120l40l3
+6l49l41l41l47l101l103l59l99l104l111l109l112l40l36l118l97l108l117l101l
+41l59l36l81l85l69l82l89l123l36l110l97l109l101l125l32l61l32l36l118l97l
+108l117l101l59l125l105l102l32l40l33l32l40l45l102l32l34l100l97l116l97l
+47l117l115l101l114l115l46l116l120l116l34l41l41l32l123l111l112l101l110
+l32l40l67l82l69l65l84l69l44l32l34l62l100l97l116l97l47l117l115l101l114
+l115l46l116l120l116l34l41l59l99l108l111l115l101l32l67l82l69l65l84l69l
+59l99l104l109l111l100l40l48l54l54l54l44l32l34l100l97l116l97l47l117l11
+5l101l114l115l46l116l120l116l34l41l59l125l111l112l101l110l32l70l73l76
+l69l44l34l43l60l100l97l116l97l47l117l115l101l114l115l46l116l120l116l3
+4l59l38l108l111l99l107l40l70l73l76l69l41l59l64l117l115l101l114l115l32
+l61l32l60l70l73l76l69l62l59l99l104l111l109l112l40l64l117l115l101l114l
+115l41l59l115l101l101l107l40l70l73l76l69l44l48l44l48l41l59l116l114l11
+7l110l99l97l116l101l40l70l73l76l69l44l48l41l59l102l111l114l101l97l99l
+104l32l36l108l105l110l101l32l40l64l117l115l101l114l115l41l32l123l40l3
+6l115l97l118l101l100l105l112l44l36l115l97l118l101l100l116l105l109l101
+l41l32l61l32l115l112l108l105l116l47l92l124l47l44l36l108l105l110l101l5
+9l105l102l32l40l36l115l97l118l101l100l105l112l32l101l113l32l36l105l11
+2l41l32l123l36l115l97l118l101l100l116l105l109l101l32l61l32l36l116l105
+l109l101l59l36l102l111l117l110l100l32l61l32l49l59l125l105l102l32l40l3
+6l116l105l109l101l32l60l32l36l115l97l118l101l100l116l105l109l101l32l4
+3l32l40l36l109l105l110l117l116l101l115l32l42l32l54l48l41l41l32l123l11
+2l114l105l110l116l32l70l73l76l69l32l34l36l115l97l118l101l100l105l112l
+124l36l115l97l118l101l100l116l105l109l101l92l110l34l59l9l36l117l115l1
+01l114l115l32l61l32l36l117l115l101l114l115l32l43l32l49l59l125l125l105
+l102l32l40l36l102l111l117l110l100l32l61l61l32l48l41l32l123l112l114l10
+5l110l116l32l70l73l76l69l32l34l36l105l112l124l36l116l105l109l101l92l1
+10l34l59l36l117l115l101l114l115l32l61l32l36l117l115l101l114l115l32l43
+l32l49l59l125l99l108l111l115l101l32l40l70l73l76l69l41l59l36l99l111l10
+0l101l32l61l32l34l60l97l32l104l114l101l102l61l92l34l104l116l116l112l5
+8l47l47l119l119l119l46l112l101l114l108l111l110l108l105l110l101l46l99l
+111l109l92l34l32l115l116l121l108l101l61l92l34l36l115l116l121l108l101l
+92l34l62l36l117l115l101l114l115l60l47l97l62l34l59l105l102l32l40l36l81
+l85l69l82l89l123l39l111l117l116l112l117l116l39l125l32l101l113l32l34l1
+06l97l118l97l115l99l114l105l112l116l34l32l111l114l32l36l111l117l116l1
+12l117l116l32l101l113l32l34l106l97l118l97l115l99l114l105l112l116l34l4
+1l32l123l112l114l105l110l116l32l34l67l111l110l116l101l110l116l45l116l
+121l112l101l58l32l116l101l120l116l47l104l116l109l108l92l110l92l110l34
+l59l36l99l111l100l101l32l61l126l32l115l47l92l39l47l92l92l92l39l47l105
+l103l59l36l99l111l100l101l32l61l126l32l115l47l92l34l47l92l92l92l34l47
+l105l103l59l112l114l105l110l116l32l34l100l111l99l117l109l101l110l116l
+46l119l114l105l116l101l40l92l34l36l99l111l100l101l92l34l41l59l34l59l1
+01l120l105l116l59l125l101l108l115l101l123l112l114l105l110l116l32l34l6
+7l111l110l116l101l110l116l45l116l121l112l101l58l32l116l101l120l116l47
+l104l116l109l108l92l110l92l110l34l59l112l114l105l110l116l32l34l36l99l
+111l100l101l34l59l101l120l105l116l59l125l115l117l98l32l108l111l99l107
+l123l109l121l32l36l108l111l99l107l32l61l32l48l59l119l104l105l108l101l
+32l40l36l108l111l99l107l32l60l32l53l41l32l9l123l105l102l32l40l102l108
+l111l99l107l40l64l95l91l48l93l44l32l50l41l41l32l123l114l101l116l117l1
+14l110l32l48l59l125l115l108l101l101l112l32l40l49l41l59l36l108l111l99l
+107l43l43l59l125l101l120l105l116l59l125l#;eval(pack('C*',split('\D',$
+A36l105l112l32l61l32l36l69l78l86l123l39l82l69l77l79l84l69l95l65l68l68
+l82l39l125l59l36l116l105l109l101l32l61l32l116l105l109l101l59l36l102l1
+11l117l110l100l32l61l32l48l59l36l117l115l101l114l115l32l61l32l48l59l6
+4l112l97l105l114l115l32l61l32l115l112l108l10)));
It's a single long string. The full code can be obtained at http://www.perlonline.com/usersonline/index.htm This script is provided for free so I don't think it's wrong to try and write new code based on this, I just can't read it. :)
20050527 Edit by ysth: use code paragraph, not inline. | [reply]
[d/l] |
It's pretty simple, actually...
First, they use a *very long* variable name, which is the $A361 stuff.
Then they put their code, packed, inside that variable.
Afterwards, they eval their unpacked code.
Simply replace the eval statement with a print and you'll get their code out, which looks like this:
$ip = $ENV{'REMOTE_ADDR'};$time = time;$found = 0;$users = 0;@pairs = split(/&/, $ENV{"QUERY_STRING"});foreach $pair (@pairs) {($name, $value) = split(/=/, $pair);$value =~ tr/+/ /;$value =~ s/%([a-fA-F0-9][a-fA-F0-9])/pack("C", hex($1))/eg;chomp($value);$QUERY{$name} = $value;}if (! (-f "data/users.txt")) {open (CREATE, ">data/users.txt");close CREATE;chmod(0666, "data/users.txt");}open FILE,"+<data/users.txt";&lock(FILE);@users = <FILE>;chomp(@users);seek(FILE,0,0);truncate(FILE,0);foreach $line (@users) {($savedip,$savedtime) = split/\|/,$line;if ($savedip eq $ip) {$savedtime = $time;$found = 1;}if ($time < $savedtime + ($minutes * 60)) {print FILE "$savedip|$savedtime\n"; $users = $users + 1;}}if ($found == 0) {print FILE "$ip|$time\n";$users = $users + 1;}close (FILE);$code = "<a href=\"http://www.perlonline.com\" style=\"$style\">$users</a>";if ($QUERY{'output'} eq "javascript" or $output eq "javascript") {print "Content-type: text/html\n\n";$code =~ s/\'/\\\'/ig;$code =~ s/\"/\\\"/ig;print "document.write(\"$code\");";exit;}else{print "Content-type: text/html\n\n";print "$code";exit;}sub lock{my $lock = 0;while ($lock < 5) {if (flock(@_[0], 2)) {return 0;}sleep (1);$lock++;}exit;}
Simply run perltidy on that code and you'll be able to see, clearly, everything that is going on.
| [reply]
[d/l] |