Refactor some Lua string concatenations.

Using this regular expression, '\(\w*\)\s*=\s*\1\s*\.\.', found and replaced many string concatenation-reassignments. These can cause performance issues, since a new string gets allocated for each reassignment. In many cases, the replacement is simply a single string, wrapped across lines with the '\z' escape, which consumes a newline and whitespace following it. In other cases, a table is used to hold the substrings until the final string is built with a single table.concat operation (same technique used in stdnse.strbuf). Also, some string-building loops of this form: s = "" for i = 1, 100, 1 do s = s .. "\0" end were replaced with this much faster and cleaner version: s = string.rep("\0", 100)
2026-02-01 02:59:01 +00:00 · 2014-02-18 18:10:23 +00:00
parent 74ebf1c892
commit 1c0c090ace
7 changed files with 160 additions and 175 deletions
--- a/nselib/citrixxml.lua
+++ b/nselib/citrixxml.lua
@@ -81,11 +81,11 @@ end
 --
 function request_server_farm_data( host, port )

-  local xmldata = "<?xml version=\"1.0\" encoding=\"ISO-8859-1\"?>\r\n"
-  xmldata = xmldata .. "<!DOCTYPE NFuseProtocol SYSTEM \"NFuse.dtd\">\r\n"
-  xmldata = xmldata .. "<NFuseProtocol version=\"1.1\">"
-  xmldata = xmldata .. "<RequestServerFarmData></RequestServerFarmData>"
-  xmldata = xmldata .. "</NFuseProtocol>\r\n"
+  local xmldata = "<?xml version=\"1.0\" encoding=\"ISO-8859-1\"?>\r\n\z
+  <!DOCTYPE NFuseProtocol SYSTEM \"NFuse.dtd\">\r\n\z
+  <NFuseProtocol version=\"1.1\">\z
+  <RequestServerFarmData></RequestServerFarmData>\z
+  </NFuseProtocol>\r\n"

  return send_citrix_xml_request(host, port, xmldata)
 end
@@ -127,20 +127,24 @@ function request_appdata(host, port, params)
  local client_type = params['ClientType'] or "ica30"
  local desired_details = params['DesiredDetails'] or nil

-  local xmldata = "<?xml version=\"1.0\" encoding=\"ISO-8859-1\"?>\r\n"
-  xmldata = xmldata .. "<!DOCTYPE NFuseProtocol SYSTEM \"NFuse.dtd\">\r\n"
-  xmldata = xmldata .. "<NFuseProtocol version=\"5.0\">"
-  xmldata = xmldata .. "<RequestAppData>"
-  xmldata = xmldata .. "<Scope traverse=\"" .. scope .. "\" />"
-  xmldata = xmldata .. "<ServerType>" .. server_type .. "</ServerType>"
-  xmldata = xmldata .. "<ClientType>" .. client_type .. "</ClientType>"
+  local xmldata = {
+    '<?xml version="1.0" encoding="ISO-8859-1"?>\r\n\z
+    <!DOCTYPE NFuseProtocol SYSTEM "NFuse.dtd">\r\n\z
+    <NFuseProtocol version="5.0"><RequestAppData><Scope traverse="',
+    scope,
+    '" /><ServerType>',
+    server_type,
+    "</ServerType><ClientType>",
+    client_type,
+    "</ClientType>"
+  }

  if desired_details then
    if type(desired_details) == "string" then
-      xmldata = xmldata .. "<DesiredDetails>" .. desired_details .. "</DesiredDetails>"
+      xmldata[#xmldata+1] = "<DesiredDetails>" .. desired_details .. "</DesiredDetails>"
    elseif type(desired_details) == "table" then
      for _, v in ipairs(desired_details) do
-        xmldata = xmldata .. "<DesiredDetails>" .. v .. "</DesiredDetails>"
+        xmldata[#xmldata+1] = "<DesiredDetails>" .. v .. "</DesiredDetails>"
      end
    else
      assert(desired_details)
@@ -148,10 +152,9 @@ function request_appdata(host, port, params)

  end

-  xmldata = xmldata .. "</RequestAppData>"
-  xmldata = xmldata .. "</NFuseProtocol>\r\n"
+  xmldata[#xmldata+1] = "</RequestAppData></NFuseProtocol>\r\n"

-  return send_citrix_xml_request(host, port, xmldata)
+  return send_citrix_xml_request(host, port, table.concat(xmldata))
 end


@@ -270,25 +273,23 @@ end
 --
 function request_address(host, port, flags, appname)

-  local xmldata = "<?xml version=\"1.0\" encoding=\"ISO-8859-1\"?>\r\n"
-  xmldata = xmldata .. "<!DOCTYPE NFuseProtocol SYSTEM \"NFuse.dtd\">\r\n"
-  xmldata = xmldata .. "<NFuseProtocol version=\"4.1\">"
-  xmldata = xmldata .. "<RequestAddress>"
+  local xmldata = {
+    '<?xml version="1.0" encoding="ISO-8859-1"?>\r\n\z
+    <!DOCTYPE NFuseProtocol SYSTEM "NFuse.dtd">\r\n\z
+    <NFuseProtocol version="4.1"><RequestAddress>'
+  }

  if flags then
-    xmldata = xmldata .. "<Flags>" .. flags .. "</Flags>"
+    xmldata[#xmldata+1] = "<Flags>" .. flags .. "</Flags>"
  end

  if appname then
-    xmldata = xmldata .. "<Name>"
-    xmldata = xmldata .. "<AppName>" .. appname .. "</AppName>"
-    xmldata = xmldata .. "</Name>"
+    xmldata[#xmldata+1] = "<Name><AppName>" .. appname .. "</AppName></Name>"
  end

-  xmldata = xmldata .. "</RequestAddress>"
-  xmldata = xmldata .. "</NFuseProtocol>\r\n"
+  xmldata[#xmldata+1] = "</RequestAddress></NFuseProtocol>\r\n"

-  return send_citrix_xml_request(host, port, xmldata)
+  return send_citrix_xml_request(host, port, table.concat(xmldata))
 end

 --- Request information about the Citrix protocol
@@ -308,23 +309,23 @@ function request_server_data(host, port, params)
  local server_type = params.ServerType or {"all"}
  local client_type = params.ClientType or {"all"}

-  local xmldata = "<?xml version=\"1.0\" encoding=\"ISO-8859-1\"?>\r\n"
-  xmldata = xmldata .. "<!DOCTYPE NFuseProtocol SYSTEM \"NFuse.dtd\">\r\n"
-  xmldata = xmldata .. "<NFuseProtocol version=\"1.1\">"
-  xmldata = xmldata .. "<RequestServerData>"
+  local xmldata = {
+    '<?xml version="1.0" encoding="ISO-8859-1"?>\r\n\z
+    <!DOCTYPE NFuseProtocol SYSTEM "NFuse.dtd">\r\n\z
+    <NFuseProtocol version="1.1"><RequestServerData>'
+  }

  for _, srvtype in pairs(server_type) do
-    xmldata = xmldata .. "<ServerType>" .. srvtype .. "</ServerType>"
+    xmldata[#xmldata+1] = "<ServerType>" .. srvtype .. "</ServerType>"
  end

  for _, clitype in pairs(client_type) do
-    xmldata = xmldata .. "<ClientType>" .. clitype .. "</ClientType>"
+    xmldata[#xmldata+1] = "<ClientType>" .. clitype .. "</ClientType>"
  end

-  xmldata = xmldata .. "</RequestServerData>"
-  xmldata = xmldata .. "</NFuseProtocol>\r\n"
+  xmldata[#xmldata+1] = "</RequestServerData></NFuseProtocol>\r\n"

-  return send_citrix_xml_request(host, port, xmldata)
+  return send_citrix_xml_request(host, port, table.concat(xmldata))
 end

 --- Parses the response from the request_server_data request
@@ -359,20 +360,21 @@ function request_protocol_info( host, port, params )

  local params = params or {}

-  local xmldata = "<?xml version=\"1.0\" encoding=\"ISO-8859-1\"?>\r\n"
-  xmldata = xmldata .. "<!DOCTYPE NFuseProtocol SYSTEM \"NFuse.dtd\">\r\n"
-  xmldata = xmldata .. "<NFuseProtocol version=\"1.1\">"
-  xmldata = xmldata .. "<RequestProtocolInfo>"
+  local xmldata = {
+    '<?xml version="1.0" encoding="ISO-8859-1"?>\r\n\z
+    <!DOCTYPE NFuseProtocol SYSTEM "NFuse.dtd">\r\n\z
+    <NFuseProtocol version="1.1"><RequestProtocolInfo>'
+  }

  if params['ServerAddress'] then
-    xmldata = xmldata .. "<ServerAddress addresstype=\"" .. params['ServerAddress']['attr']['addresstype'] .. "\">"
-    xmldata = xmldata .. params['ServerAddress'] .. "</ServerAddress>"
+    xmldata[#xmldata+1] = ('<ServerAddress addresstype="' ..
+      params['ServerAddress']['attr']['addresstype'] .. '">' ..
+      params['ServerAddress'] .. "</ServerAddress>")
  end

-  xmldata = xmldata .. "</RequestProtocolInfo>"
-  xmldata = xmldata .. "</NFuseProtocol>\r\n"
+  xmldata[#xmldata+1] = "</RequestProtocolInfo></NFuseProtocol>\r\n"

-  return send_citrix_xml_request(host, port, xmldata)
+  return send_citrix_xml_request(host, port, table.concat(xmldata))
 end

 --- Request capability information
@@ -387,12 +389,10 @@ end
 --
 function request_capabilities( host, port )

-  local xmldata = "<?xml version=\"1.0\" encoding=\"ISO-8859-1\"?>\r\n"
-  xmldata = xmldata .. "<!DOCTYPE NFuseProtocol SYSTEM \"NFuse.dtd\">\r\n"
-  xmldata = xmldata .. "<NFuseProtocol version=\"1.1\">"
-  xmldata = xmldata .. "<RequestCapabilities>"
-  xmldata = xmldata .. "</RequestCapabilities>"
-  xmldata = xmldata .. "</NFuseProtocol>\r\n"
+  local xmldata = '<?xml version="1.0" encoding="ISO-8859-1"?>\r\n\z
+  <!DOCTYPE NFuseProtocol SYSTEM "NFuse.dtd">\r\n\z
+  <NFuseProtocol version="1.1"><RequestCapabilities>\z
+  </RequestCapabilities></NFuseProtocol>\r\n'

  return send_citrix_xml_request(host, port, xmldata)
 end
@@ -431,29 +431,27 @@ function request_validate_credentials(host, port, params )
  local params = params or {}
  local credentials = params['Credentials'] or {}

-  local xmldata = "<?xml version=\"1.0\" encoding=\"ISO-8859-1\"?>\r\n"
-  xmldata = xmldata .. "<!DOCTYPE NFuseProtocol SYSTEM \"NFuse.dtd\">\r\n"
-  xmldata = xmldata .. "<NFuseProtocol version=\"5.0\">"
-  xmldata = xmldata .. "<RequestValidateCredentials>"
-  xmldata = xmldata .. "<Credentials>"
+  local xmldata = {
+    '<?xml version="1.0" encoding="ISO-8859-1"?>\r\n\z
+    <!DOCTYPE NFuseProtocol SYSTEM "NFuse.dtd">\r\n\z
+    <NFuseProtocol version="5.0"><RequestValidateCredentials><Credentials>'
+  }

  if credentials['UserName'] then
-    xmldata = xmldata .. "<UserName>" .. credentials['UserName'] .. "</UserName>"
+    xmldata[#xmldata+1] = "<UserName>" .. credentials['UserName'] .. "</UserName>"
  end

  if credentials['Password'] then
-    xmldata = xmldata .. "<Password encoding=\"cleartext\">" .. credentials['Password'] .. "</Password>"
+    xmldata[#xmldata+1] = '<Password encoding="cleartext">' .. credentials['Password'] .. "</Password>"
  end

  if credentials['Domain'] then
-    xmldata = xmldata .. "<Domain type=\"NT\">" .. credentials['Domain'] .. "</Domain>"
+    xmldata[#xmldata+1] = '<Domain type="NT">' .. credentials['Domain'] .. "</Domain>"
  end

-  xmldata = xmldata .. "</Credentials>"
-  xmldata = xmldata .. "</RequestValidateCredentials>"
-  xmldata = xmldata .. "</NFuseProtocol>\r\n"
+  xmldata[#xmldata+1] = "</Credentials></RequestValidateCredentials></NFuseProtocol>\r\n"

-  return send_citrix_xml_request(host, port, xmldata)
+  return send_citrix_xml_request(host, port, table.concat(xmldata))

 end

@@ -491,47 +489,45 @@ function request_reconnect_session_data(host, port, params)
  params.ServerType = params.ServerType or {}
  params.ClientType = params.ClientType or {}

-  local xmldata = "<?xml version=\"1.0\" encoding=\"ISO-8859-1\"?>\r\n"
-  xmldata = xmldata .. "<!DOCTYPE NFuseProtocol SYSTEM \"NFuse.dtd\">\r\n"
-  xmldata = xmldata .. "<NFuseProtocol version=\"5.0\">"
-  xmldata = xmldata .. "<RequestReconnectSessionData>"
-
-  xmldata = xmldata .. "<Credentials>"
+  local xmldata = {
+    '<?xml version="1.0" encoding="ISO-8859-1"?>\r\n\z
+    <!DOCTYPE NFuseProtocol SYSTEM "NFuse.dtd">\r\n\z
+    <NFuseProtocol version="5.0"><RequestReconnectSessionData><Credentials>'
+  }

  if Credentials.UserName then
-    xmldata = xmldata .. "<UserName>" .. Credentials.UserName .. "</UserName>"
+    xmldata[#xmldata+1] = "<UserName>" .. Credentials.UserName .. "</UserName>"
  end

  if Credentials.Password then
-    xmldata = xmldata .. "<Password encoding=\"cleartext\">" .. Credentials.Password .. "</Password>"
+    xmldata[#xmldata+1] = '<Password encoding="cleartext">' .. Credentials.Password .. "</Password>"
  end

  if Credentials.Domain then
-    xmldata = xmldata .. "<Domain type=\"NT\">" .. Credentials.Domain .. "</Domain>"
+    xmldata[#xmldata+1] = '<Domain type="NT">' .. Credentials.Domain .. "</Domain>"
  end

-  xmldata = xmldata .. "</Credentials>"
+  xmldata[#xmldata+1] = "</Credentials>"

  if params.ClientName then
-    xmldata = xmldata .. "<ClientName>" .. params.ClientName .. "</ClientName>"
+    xmldata[#xmldata+1] = "<ClientName>" .. params.ClientName .. "</ClientName>"
  end

  if params.DeviceId then
-    xmldata = xmldata .. "<DeviceId>" .. params.DeviceId .. "</DeviceId>"
+    xmldata[#xmldata+1] = "<DeviceId>" .. params.DeviceId .. "</DeviceId>"
  end

  for _, srvtype in pairs(params.ServerType) do
-    xmldata = xmldata .. "<ServerType>" .. srvtype .. "</ServerType>"
+    xmldata[#xmldata+1] = "<ServerType>" .. srvtype .. "</ServerType>"
  end

  for _, clitype in pairs(params.ClientType) do
-    xmldata = xmldata .. "<ClientType>" .. clitype .. "</ClientType>"
+    xmldata[#xmldata+1] = "<ClientType>" .. clitype .. "</ClientType>"
  end

-  xmldata = xmldata .. "</RequestReconnectSessionData>"
-  xmldata = xmldata .. "</NFuseProtocol>\r\n"
+  xmldata[#xmldata+1] = "</RequestReconnectSessionData></NFuseProtocol>\r\n"

-  return send_citrix_xml_request(host, port, xmldata)
+  return send_citrix_xml_request(host, port, table.concat(xmldata))


 end
--- a/nselib/drda.lua
+++ b/nselib/drda.lua
@@ -721,23 +721,23 @@ Comm = {
 }

 -- EBCDIC/ASCII Conversion tables
-a2e_hex = "00010203372D2E2F1605250B0C0D0E0F101112133C3D322618193F271C1D1E1F"
-a2e_hex = a2e_hex .. "405A7F7B5B6C507D4D5D5C4E6B604B61F0F1F2F3F4F5F6F7F8F97A5E4C7E6E6F"
-a2e_hex = a2e_hex .. "7CC1C2C3C4C5C6C7C8C9D1D2D3D4D5D6D7D8D9E2E3E4E5E6E7E8E9ADE0BD5F6D"
-a2e_hex = a2e_hex .. "79818283848586878889919293949596979899A2A3A4A5A6A7A8A9C04FD0A107"
-a2e_hex = a2e_hex .. "202122232415061728292A2B2C090A1B30311A333435360838393A3B04143EE1"
-a2e_hex = a2e_hex .. "4142434445464748495152535455565758596263646566676869707172737475"
-a2e_hex = a2e_hex .. "767778808A8B8C8D8E8F909A9B9C9D9E9FA0AAABAC4AAEAFB0B1B2B3B4B5B6B7"
-a2e_hex = a2e_hex .. "B8B9BABBBC6ABEBFCACBCCCDCECFDADBDCDDDEDFEAEBECEDEEEFFAFBFCFDFEFF"
+a2e_hex = "00010203372D2E2F1605250B0C0D0E0F101112133C3D322618193F271C1D1E1F\z
+405A7F7B5B6C507D4D5D5C4E6B604B61F0F1F2F3F4F5F6F7F8F97A5E4C7E6E6F\z
+7CC1C2C3C4C5C6C7C8C9D1D2D3D4D5D6D7D8D9E2E3E4E5E6E7E8E9ADE0BD5F6D\z
+79818283848586878889919293949596979899A2A3A4A5A6A7A8A9C04FD0A107\z
+202122232415061728292A2B2C090A1B30311A333435360838393A3B04143EE1\z
+4142434445464748495152535455565758596263646566676869707172737475\z
+767778808A8B8C8D8E8F909A9B9C9D9E9FA0AAABAC4AAEAFB0B1B2B3B4B5B6B7\z
+B8B9BABBBC6ABEBFCACBCCCDCECFDADBDCDDDEDFEAEBECEDEEEFFAFBFCFDFEFF"

-e2a_hex = "000102039C09867F978D8E0B0C0D0E0F101112139D8508871819928F1C1D1E1F"
-e2a_hex = e2a_hex .. "80818283840A171B88898A8B8C050607909116939495960498999A9B14159E1A"
-e2a_hex = e2a_hex .. "20A0A1A2A3A4A5A6A7A8D52E3C282B7C26A9AAABACADAEAFB0B121242A293B5E"
-e2a_hex = e2a_hex .. "2D2FB2B3B4B5B6B7B8B9E52C255F3E3FBABBBCBDBEBFC0C1C2603A2340273D22"
-e2a_hex = e2a_hex .. "C3616263646566676869C4C5C6C7C8C9CA6A6B6C6D6E6F707172CBCCCDCECFD0"
-e2a_hex = e2a_hex .. "D17E737475767778797AD2D3D45BD6D7D8D9DADBDCDDDEDFE0E1E2E3E45DE6E7"
-e2a_hex = e2a_hex .. "7B414243444546474849E8E9EAEBECED7D4A4B4C4D4E4F505152EEEFF0F1F2F3"
-e2a_hex = e2a_hex .. "5C9F535455565758595AF4F5F6F7F8F930313233343536373839FAFBFCFDFEFF"
+e2a_hex = "000102039C09867F978D8E0B0C0D0E0F101112139D8508871819928F1C1D1E1F\z
+80818283840A171B88898A8B8C050607909116939495960498999A9B14159E1A\z
+20A0A1A2A3A4A5A6A7A8D52E3C282B7C26A9AAABACADAEAFB0B121242A293B5E\z
+2D2FB2B3B4B5B6B7B8B9E52C255F3E3FBABBBCBDBEBFC0C1C2603A2340273D22\z
+C3616263646566676869C4C5C6C7C8C9CA6A6B6C6D6E6F707172CBCCCDCECFD0\z
+D17E737475767778797AD2D3D45BD6D7D8D9DADBDCDDDEDFE0E1E2E3E45DE6E7\z
+7B414243444546474849E8E9EAEBECED7D4A4B4C4D4E4F505152EEEFF0F1F2F3\z
+5C9F535455565758595AF4F5F6F7F8F930313233343536373839FAFBFCFDFEFF"

 -- Creates the lookup tables needed for conversion
 a2e_tbl = bin.pack("H", a2e_hex)
--- a/nselib/rmi.lua
+++ b/nselib/rmi.lua
@@ -448,33 +448,33 @@ JavaClass = {
  end,

  __tostring = function( self )
-    local data
+    local data = {}
    if self.name ~=nil then
-      data = ("%s "):format(self.name)
+      data[#data+1] = ("%s "):format(self.name)
    else
-      data = "???"
+      data[#data+1] = "???"
    end
    if  self.superClass~=nil then
-      data = data .. " extends ".. tostring( self.superClass)
+      data[#data+1] = " extends ".. tostring( self.superClass)
    end
    if self.ifaces ~= nil then
-      data = data .. " implements " ..  self.ifaces
+      data[#data+1] = " implements " ..  self.ifaces
    end
    if self.fields ~=nil then
      for i=1, #self.fields do
        if i == 1 then
-          data = data .. "["
+          data[#data+1] = "["
        end
-        data = data .. tostring(self.fields[i])
+        data[#data+1] = tostring(self.fields[i])
        if ( i < #self.fields ) then
-          data = data .. ";"
+          data[#data+1] = ";"
        else
-          data = data .. "]"
+          data[#data+1] = "]"
        end

      end
    end
-    return data
+    return table.concat(data)
  end,
  toTable = function(self, customDataFormatter)
    local data = {self.name}
@@ -571,7 +571,8 @@ JavaField = {
          table.insert(data, self.value)
        end
      else
-        data = data .." = " .. tostring(self.value)
+        --TODO: FIXME This is illegal, but I don't know what the intent was:
+        data = data .." = " .. tostring(self.value) --FIXME
      end
    end
    return data
@@ -592,13 +593,15 @@ JavaArray = {
  setLength = function( self, length ) self.length = length end,
  setValue = function(self, index, object) self.values[index] = object end,
  __tostring=function(self)
-    local data =  ("Array: %s [%d] = {"):format(tostring(self.class), self.length)
+    local data = {
+      ("Array: %s [%d] = {"):format(tostring(self.class), self.length)
+    }

    for i=1, #self.values do
-      data = data .. self.values[i]..","
+      data[#data+1] = self.values[i]..","
    end
-    data = data .."}"
-    return data
+    data[#data+1] = "}"
+    return table.concat(data)
  end,
  toTable = function(self)
    local title = ("Array: %s [%d] = {"):format(tostring(self.class), self.length)
--- a/nselib/rpc.lua
+++ b/nselib/rpc.lua
@@ -325,10 +325,12 @@ Comm = {
      packet = packet .. bin.pack( "IIII", 0, 0, 0, 0 )
    elseif auth.type == Portmap.AuthType.UNIX then
      packet = packet .. Util.marshall_int32(auth.type)
-      local blob = Util.marshall_int32(nmap.clock()) --time
-      blob = blob .. Util.marshall_vopaque(auth.hostname or 'localhost')
-      blob = blob .. Util.marshall_int32(auth.uid or 0)
-      blob = blob .. Util.marshall_int32(auth.gid or 0)
+      local blob = (
+        Util.marshall_int32(nmap.clock()) --time
+        .. Util.marshall_vopaque(auth.hostname or 'localhost')
+        .. Util.marshall_int32(auth.uid or 0)
+        .. Util.marshall_int32(auth.gid or 0)
+        )
      if auth.gids then --len prefix gid list
        blob = blob .. Util.marshall_int32(#auth.gids)
        for _,gid in ipairs(auth.gids) do
@@ -337,8 +339,9 @@ Comm = {
      else
        blob = blob .. Util.marshall_int32(0)
      end
-      packet = packet .. Util.marshall_vopaque(blob)
-      packet = packet .. bin.pack( "II", 0, 0 ) --AUTH_NULL verf
+      packet = (packet .. Util.marshall_vopaque(blob)
+        .. bin.pack( "II", 0, 0 ) --AUTH_NULL verf
+        )
    else
      return false, "Comm.CreateHeader: invalid authentication type specified"
    end
@@ -2981,10 +2984,7 @@ Util =
  -- @param mode number containing the ACL mode
  -- @return string containing the ACL characters
  FpermToString = function(mode)
-    local tmpacl, acl = {}, ""
-    for i = 1, 9 do
-      tmpacl[i] = "-"
-    end
+    local tmpacl = { "-", "-", "-", "-", "-", "-", "-", "-", "-" }

    for user,_ in pairs(Util.Fperm) do
      local t = Util.Fperm[user]
@@ -3009,11 +3009,7 @@ Util =
      end
    end

-    for i = 1,#tmpacl do
-      acl = acl .. tmpacl[i]
-    end
-
-    return acl
+    return table.concat(tmpacl)
  end,

  --- Converts the NFS file attributes to a string.
@@ -3096,11 +3092,7 @@ Util =
  end,

  marshall_opaque = function(data)
-    local opaque = bin.pack(">A", data)
-    for i = 1, Util.CalcFillBytes(data:len()) do
-      opaque = opaque .. string.char(0x00)
-    end
-    return opaque
+    return bin.pack(">A", data) .. string.rep("\0", Util.CalcFillBytes(data:len()))
  end,

  unmarshall_opaque = function(len, data, pos)
@@ -3108,13 +3100,11 @@ Util =
  end,

  marshall_vopaque = function(data)
-    local opaque, l
-    l = data:len()
-    opaque = Util.marshall_uint32(l) .. bin.pack(">A", data)
-    for i = 1, Util.CalcFillBytes(l) do
-      opaque = opaque .. string.char(0x00)
-    end
-    return opaque
+    local l = data:len()
+    return (
+      Util.marshall_uint32(l) .. bin.pack(">A", data) ..
+      string.rep("\0", Util.CalcFillBytes(l))
+      )
  end,

  unmarshall_vopaque = function(len, data, pos)
--- a/nselib/upnp.lua
+++ b/nselib/upnp.lua
@@ -94,14 +94,13 @@ Comm = {
  --
  -- @return status true on success, false on failure
  sendRequest = function( self )
-    local payload = strbuf.new()

    -- for details about the UPnP message format, see http://upnp.org/resources/documents.asp
-    payload = payload .. "M-SEARCH * HTTP/1.1\r\n"
-    payload = payload .. "Host:239.255.255.250:1900\r\n"
-    payload = payload .. "ST:upnp:rootdevice\r\n"
-    payload = payload .. "Man:\"ssdp:discover\"\r\n"
-    payload = payload .. "MX:3\r\n\r\n"
+    local payload = 'M-SEARCH * HTTP/1.1\r\n\z
+    Host:239.255.255.250:1900\r\n\z
+    ST:upnp:rootdevice\r\n\z
+    Man:"ssdp:discover"\r\n\z
+    MX:3\r\n\r\n'

    local status, err

--- a/nselib/url.lua
+++ b/nselib/url.lua
@@ -290,29 +290,27 @@ end
 -- @return The corresponding path string
 -----------------------------------------------------------------------------
 function build_path(parsed, unsafe)
-  local path = ""
+  local path = {}
+  if parsed.is_absolute then path[#path+1] = "/" end
  local n = #parsed
  if unsafe then
    for i = 1, n-1 do
-      path = path .. parsed[i]
-      path = path .. "/"
+      path[#path+1] = parsed[i] .. "/"
    end
    if n > 0 then
-      path = path .. parsed[n]
-      if parsed.is_directory then path = path .. "/" end
+      path[#path+1] = parsed[n]
+      if parsed.is_directory then path[#path+1] = "/" end
    end
  else
    for i = 1, n-1 do
-      path = path .. protect_segment(parsed[i])
-      path = path .. "/"
+      path[#path+1] = protect_segment(parsed[i]) .. "/"
    end
    if n > 0 then
-      path = path .. protect_segment(parsed[n])
-      if parsed.is_directory then path = path .. "/" end
+      path[#path+1] = protect_segment(parsed[n])
+      if parsed.is_directory then path[#path+1] = "/" end
    end
  end
-  if parsed.is_absolute then path = "/" .. path end
-  return path
+  return table.concat(path)
 end

 ---
--- a/nselib/versant.lua
+++ b/nselib/versant.lua
@@ -13,6 +13,7 @@ local bin = require "bin"
 local match = require "match"
 local nmap = require "nmap"
 local package = require "package"
+local string = require "string"
 local table = require "table"
 _ENV = stdnse.module("versant", stdnse.seeall)

@@ -60,22 +61,22 @@ Versant = {
    ver = ver or Versant.VERSION
    arg = arg or ""

-    local data = bin.pack("H", "000100000000000000020002000000010000000000000000000000000000000000010000")
-    data = data .. cmd .. "\0" .. user .. "\0" .. ver .. "\0"
+    local data = bin.pack("Hzzz",
+      "000100000000000000020002000000010000000000000000000000000000000000010000",
+      cmd,
+      user,
+      ver
+      )
    -- align to even 4 bytes
-    if ( #data % 4 ~= 0 ) then
-      for i=1, ( 4 - (#data % 4)) do
-        data = data .. "\0"
-      end
-    end
+    data = data .. string.rep("\0", 4 - ((#data % 4) or 0))

-    data = data .. bin.pack("H", "0000000b000001000000000000000000")
-    data = data .. ("%s:%d\0"):format(self.host.ip, self.port.number)
-    data = data .. "\0\0\0\0\0\0\0\0\0\0" .. arg
+    data = data .. bin.pack("Hzxxxxxxxxxxz",
+      "0000000b000001000000000000000000",
+      ("%s:%d"):format(self.host.ip, self.port.number),
+      arg
+      )

-    while ( #data < 2048 ) do
-      data = data .. "\0"
-    end
+    data = data .. string.rep("\0", 2048 - #data)

    local status, err = self.socket:send(data)
    if ( not(status) ) then
@@ -254,12 +255,10 @@ Versant.OBE = {
  --         <code>lib_path</code> - the library directory
  --         <code>hostname</code> - the database host name
  getVODInfo = function(self)
-    local data = bin.pack("H", "1002005d00000000000100000000000d000000000000000000000000")
-    data = data .. "-noprint -i "
-
-    while( #data < 256 ) do
-      data = data .. "\0"
-    end
+    local data = bin.pack("Hz",
+      "1002005d00000000000100000000000d000000000000000000000000", --28
+      "-noprint -i " --12 + 1 (for null)
+      ) .. string.rep("\0", 215) -- 256 - (28 + 12 + 1)

    self.socket:send(data)
    local status, data = self.socket:receive_buf(match.numbytes(256), true)