") print(title) print(" </title") print(' <link rel="stylesheet" href="ctf.css" type="text/css">') print(" </head>") print(" <body>") print(" <h1>") print(title) print(" </h1>") end function foot() print(" </body>") print("</html>") os.exit() end if (os.getenv("REQUEST_METHOD") ~= "POST") then print("405 Method not allowed") print("Allow: POST") print("Content-type: text/html") print() print("<h1>Method not allowed</h1>") print("<p>I only speak POST. Sorry.</p>") end inlen = tonumber(os.getenv("CONTENT_LENGTH")) if (inlen > 200) then head("Bad team name") print("<p>That's a bit on the long side, don't you think?</p>") foot() end formdata = io.read(inlen) f = decode_query(formdata) team = f["t"] if (not team) or (team == "dirtbags") then head("Bad team name") print("<p>Go back and try again.</p>") foot() end hash = djbhash(team) if io.open(hash) then head("Team name taken") print("<p>Either someone's already using that team name,") print("or you found a hash collision. Either way, you're") print("going to have to pick something else.</p>") foot() end f = io.open(hash, "w"):write(team) head("Team registered") print("<p>Team name: <samp>") print(escape(team)) print("</samp></p>") print("<p>Team token: <samp>") print(hash) print("</samp></p>") print("<p><b>Save your team token somewhere</b>!") print("You will need it to claim points.</p>") foot()

#! /usr/bin/lua function decode(str) local hexdec = function(h) return string.char(tonumber(h, 16)) end str = string.gsub(str, "+", " ") return string.gsub(str, "%%(%x%x)", hexdec) end function decode_query(query) local ret = {} for key, val in string.gfind(query, "([^&=]+)=([^&=]+)") do ret[string.lower(decode(key))] = decode(val) end return ret end function escape(str) str = string.gsub(str, "&", "&") str = string.gsub(str, "<", "<") str = string.gsub(str, ">", ">") return str end function djbhash(s) local hash = 5380 for i=0,string.len(s) do local c = string.byte(string.sub(s, i, i+1)) hash = math.mod(((hash * 32) + hash + c), 2147483647) end return string.format("%08x", hash) end function head(title) print("Content-type: text/html") print("") print("") print("") print(" ") print(" ") print(title) print(" </title") print(' <link rel="stylesheet" href="ctf.css" type="text/css">') print(" </head>") print(" <body>") print(" <h1>") print(title) print(" </h1>") end function foot() print(" </body>") print("</html>") os.exit() end if (os.getenv("REQUEST_METHOD") ~= "POST") then print("405 Method not allowed") print("Allow: POST") print("Content-type: text/html") print() print("<h1>Method not allowed</h1>") print("<p>I only speak POST. Sorry.</p>") end inlen = tonumber(os.getenv("CONTENT_LENGTH")) if (inlen > 200) then head("Bad team name") print("<p>That's a bit on the long side, don't you think?</p>") foot() end formdata = io.read(inlen) f = decode_query(formdata) team = f["t"] if (not team) or (team == "dirtbags") then head("Bad team name") print("<p>Go back and try again.</p>") foot() end hash = djbhash(team) if io.open(hash) then head("Team name taken") print("<p>Either someone's already using that team name,") print("or you found a hash collision. Either way, you're") print("going to have to pick something else.</p>") foot() end f = io.open(hash, "w"):write(team) head("Team registered") print("<p>Team name: <samp>") print(escape(team)) print("</samp></p>") print("<p>Team token: <samp>") print(hash) print("</samp></p>") print("<p><b>Save your team token somewhere</b>!") print("You will need it to claim points.</p>") foot()