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Diffstat (limited to 'nselib/slaxml.lua')
| -rw-r--r-- | nselib/slaxml.lua | 449 |
1 files changed, 449 insertions, 0 deletions
diff --git a/nselib/slaxml.lua b/nselib/slaxml.lua new file mode 100644 index 0000000..f4ea7f3 --- /dev/null +++ b/nselib/slaxml.lua @@ -0,0 +1,449 @@ +--- +-- This is the NSE implementation of SLAXML. +-- SLAXML is a pure-Lua SAX-like streaming XML parser. It is more robust +-- than many (simpler) pattern-based parsers that exist, properly supporting +-- code like <code><expr test="5 > 7" /></code>, CDATA nodes, comments, +-- namespaces, and processing instructions. +-- It is currently not a truly valid XML parser, however, as it allows certain XML that is +-- syntactically-invalid (not well-formed) to be parsed without reporting an error. +-- The streaming parser does a simple pass through the input and reports what it sees along the way. +-- You can optionally ignore white-space only text nodes using the <code>stripWhitespace</code> option. +-- The library contains the parser class and the parseDOM function. +-- +-- Basic Usage of the library: +-- <code> +-- local parser = parser:new() +-- parser:parseSAX(xmlbody, {stripWhitespace=true}) +-- </code> +-- To specify custom call backs use : +-- <code> +-- local call_backs = { +-- startElement = function(name,nsURI,nsPrefix) end, -- When "<foo" or <x:foo is seen +-- attribute = function(name,value,nsURI,nsPrefix) end, -- attribute found on current element +-- closeElement = function(name,nsURI) end, -- When "</foo>" or </x:foo> or "/>" is seen +-- text = function(text) end, -- text and CDATA nodes +-- comment = function(content) end, -- comments +-- pi = function(target,content) end, -- processing instructions e.g. "<?yes mon?>" +-- } +-- local parser = parser:new(call_backs) +-- parser:parseSAX(xmlbody) +-- </code> +-- The code also contains the <code>parseDOM</code> function. +-- To get the dom table use the <code>parseDOM</code> method as follows. +-- <code> +-- parseDOM(xmlbody, options) +-- </code> +-- +-- DOM Table Features +-- +-- Document - the root table returned from the parseDOM() method. +-- +-- * <code>doc.type</code> : the string "document" +-- * <code>doc.name</code> : the string "#doc" +-- * <code>doc.kids</code> : an array table of child processing instructions, the root element, and comment nodes. +-- * <code>doc.root</code> : the root element for the document +-- +-- Element +-- +-- * <code>someEl.type</code> : the string "element" +-- * <code>someEl.name</code> : the string name of the element (without any namespace prefix) +-- * <code>someEl.nsURI</code> : the namespace URI for this element; nil if no namespace is applied +-- * <code>someEl.attr</code> : a table of attributes, indexed by name and index +-- +-- <code>local value = someEl.attr['attribute-name']</code> : any namespace prefix of the attribute is not part of the name +-- +-- <code>local someAttr = someEl.attr[1]</code> : an single attribute table (see below); useful for iterating all +-- attributes of an element, or for disambiguating attributes with the same name in different namespaces +-- +-- * <code>someEl.kids</code> : an array table of child elements, text nodes, comment nodes, and processing instructions +-- * <code>someEl.el</code> : an array table of child elements only +-- * <code>someEl.parent</code> : reference to the parent element or document table +-- +-- Attribute +-- +-- * <code>someAttr.type</code> : the string "attribute" +-- * <code>someAttr.name</code> : the name of the attribute (without any namespace prefix) +-- * <code>someAttr.value</code> : the string value of the attribute (with XML and numeric entities unescaped) +-- * <code>someAttr.nsURI</code> : the namespace URI for the attribute; nil if no namespace is applied +-- * <code>someAttr.parent</code> : reference to the owning element table +-- +-- Text - for both CDATA and normal text nodes +-- +-- * <code>someText.type</code> : the string "text" +-- * <code>someText.name</code> : the string "#text" +-- * <code>someText.value</code> : the string content of the text node (with XML and numeric entities unescaped for non-CDATA elements) +-- * <code>someText.parent</code> : reference to the parent element table +-- +-- Comment +-- +-- * <code>someComment.type</code> : the string "comment" +-- * <code>someComment.name</code> : the string "#comment" +-- * <code>someComment.value</code> : the string content of the attribute +-- * <code>someComment.parent</code> : reference to the parent element or document table +-- +-- Processing Instruction +-- +-- * <code>someComment.type</code> : the string "pi" +-- * <code>someComment.name</code> : the string name of the PI, e.g. <?foo …?> has a name of "foo" +-- * <code>someComment.value</code> : the string content of the PI, i.e. everything but the name +-- * <code>someComment.parent</code> : reference to the parent element or document table +-- +-- @args slaxml.debug Debug level at which default callbacks will print detailed +-- parsing info. Default: 3 +-- +-- @author Gavin Kistner <original pure lua implemetation> +-- @author Gyanendra Mishra <NSE specific implementation> + +--[=====================================================================[ +v0.7 Copyright © 2013-2014 Gavin Kistner <!@phrogz.net>; MIT Licensed +See http://github.com/Phrogz/SLAXML for details. +--]=====================================================================] + +local string = require "string" +local stdnse = require "stdnse" +local table = require "table" +local unicode = require "unicode" +_ENV = stdnse.module("slaxml", stdnse.seeall) + + + + +-- A table containing the default call backs to be used +-- This really floods the script output, you will mostly be +-- using custom call backs. +-- Set the debugging level required for the default call backs. Defaults to 3. +local debugging_level = tonumber(stdnse.get_script_args('slaxml.debug')) or 3 +local DEFAULT_CALLBACKS = { + --- A call back for processing instructions. + -- To use define pi = function(<target>, <content>) <function body> end in parser._call table. + -- Executes whenever a processing instruction is found. + -- @param target the PI target + -- @param content any value not containing the sequence '?>' + pi = function(target,content) + stdnse.debug(debugging_level, string.format("<?%s %s?>",target,content)) + end, + --- A call back for comments. + -- To use define comment = function(<content>) <function body> end in parser._call table. + -- Executes whenever a comment is encountered. + -- @param content The comment body itself. + comment = function(content) + stdnse.debug(debugging_level, debugging_level, string.format("<!-- %s -->",content)) + end, + --- A call back for the start of elements. + -- To use define startElement = function(<name>, <nsURI>, <nsPrefix>) <function body> end in parser._call table. + -- Executes whenever an element starts. + -- @param name The name of the element. + -- @param nsURI The name space URI. + -- @param nsPrefix The name space prefix. + startElement = function(name,nsURI,nsPrefix) + local output = "<" + if nsPrefix then output = output .. nsPrefix .. ":" end + output = output .. name + if nsURI then output = output .. " (ns='" .. nsURI .. "')" end + output = output .. ">" + stdnse.debug(debugging_level, output) + end, + --- A call back for attributes. + -- To use define attribute = function(<name>, <attribtute>, <nsURI>, <nsPrefix>) <function body> end in parser._call table. + -- Executes whenever an attribute is found. + -- @param name The name of the attribute. + -- @param value The value of the attribute. + -- @param nsURI The name space URI. + -- @param nsPrefix The name space prefix. + attribute = function(name,value,nsURI,nsPrefix) + local output = ' ' + if nsPrefix then output = output .. nsPrefix .. ":" end + output = output .. name .. '=' .. string.format('%q',value) + if nsURI then output = output .. (" (ns='" .. nsURI .. "')") end + stdnse.debug(debugging_level, output) + end, + --- A call back for text content. + -- To use define text = function(<text>) <function body> end in parser._call table. + -- Executes whenever pure text is found. + -- @param text The actual text. + text = function(text) + stdnse.debug(debugging_level, string.format(" text: %q",text)) + end, + --- A call back for the end of elements. + -- To use define closeElement = function(<name>, <nsURI>, <nsPrefix>) <function body> end in parser._call table. + -- Executes whenever an element closes. + -- @param name The name of the element. + -- @param nsURI The name space URI. + -- @param nsPrefix The name space prefix. + closeElement = function(name,nsURI,nsPrefix) + stdnse.debug(debugging_level, string.format("</%s>",name)) + end, + } + +local entityMap = { ["lt"]="<", ["gt"]=">", ["amp"]="&", ["quot"]='"', ["apos"]="'" } +local entitySwap = function(orig,n,s) return entityMap[s] or n=="#" and unicode.utf8_enc(tonumber('0'..s)) or orig end + +parser = { + + new = function(self, callbacks) + local o = { + _call = callbacks or DEFAULT_CALLBACKS + } + setmetatable(o, self) + self.__index = self + return o + end, + + unescape = function(str) return string.gsub( str, '(&(#?)([%d%a]+);)', entitySwap ) end, + + --- Parses the xml in sax like manner. + -- @self The parser object. + -- @param xml The xml body to be parsed. + -- @param options Options if any specified. + parseSAX = function(self, xml, options) + if not options then options = { stripWhitespace=false } end + + -- Cache references for maximum speed + local find, sub, gsub, char, push, pop, concat = string.find, string.sub, string.gsub, string.char, table.insert, table.remove, table.concat + local first, last, match1, match2, match3, pos2, nsURI + local unpack = table.unpack + local pos = 1 + local state = "text" + local textStart = 1 + local currentElement={} + local currentAttributes={} + local currentAttributeCt -- manually track length since the table is re-used + local nsStack = {} + local anyElement = false + + local function finishText() + if first>textStart and self._call.text then + local text = sub(xml,textStart,first-1) + if options.stripWhitespace then + text = gsub(text,'^%s+','') + text = gsub(text,'%s+$','') + if #text==0 then text=nil end + end + if text then self._call.text(parser.unescape(text)) end + end + end + + local function findPI() + first, last, match1, match2 = find( xml, '^<%?([:%a_][:%w_.-]*) ?(.-)%?>', pos ) + if first then + finishText() + if self._call.pi then self._call.pi(match1,match2) end + pos = last+1 + textStart = pos + return true + end + end + + local function findComment() + first, last, match1 = find( xml, '^<!%-%-(.-)%-%->', pos ) + if first then + finishText() + if self._call.comment then self._call.comment(match1) end + pos = last+1 + textStart = pos + return true + end + end + + local function nsForPrefix(prefix) + if prefix=='xml' then return 'http://www.w3.org/XML/1998/namespace' end -- http://www.w3.org/TR/xml-names/#ns-decl + for i=#nsStack,1,-1 do if nsStack[i][prefix] then return nsStack[i][prefix] end end + stdnse.debug1(("Cannot find namespace for prefix %s"):format(prefix)) + return + end + + local function startElement() + anyElement = true + first, last, match1 = find( xml, '^<([%a_][%w_.-]*)', pos ) + if first then + currentElement[2] = nil -- reset the nsURI, since this table is re-used + currentElement[3] = nil -- reset the nsPrefix, since this table is re-used + finishText() + pos = last+1 + first,last,match2 = find(xml, '^:([%a_][%w_.-]*)', pos ) + if first then + currentElement[1] = match2 + currentElement[3] = match1 -- Save the prefix for later resolution + match1 = match2 + pos = last+1 + else + currentElement[1] = match1 + for i=#nsStack,1,-1 do if nsStack[i]['!'] then currentElement[2] = nsStack[i]['!']; break end end + end + currentAttributeCt = 0 + push(nsStack,{}) + return true + end + end + + local function findAttribute() + first, last, match1 = find( xml, '^%s+([:%a_][:%w_.-]*)%s*=%s*', pos ) + if first then + pos2 = last+1 + first, last, match2 = find( xml, '^"([^<"]*)"', pos2 ) -- FIXME: disallow non-entity ampersands + if first then + pos = last+1 + match2 = parser.unescape(match2) + else + first, last, match2 = find( xml, "^'([^<']*)'", pos2 ) -- FIXME: disallow non-entity ampersands + if first then + pos = last+1 + match2 = parser.unescape(match2) + end + end + end + if match1 and match2 then + local currentAttribute = {match1,match2} + local prefix,name = string.match(match1,'^([^:]+):([^:]+)$') + if prefix then + if prefix=='xmlns' then + nsStack[#nsStack][name] = match2 + else + currentAttribute[1] = name + currentAttribute[4] = prefix + end + else + if match1=='xmlns' then + nsStack[#nsStack]['!'] = match2 + currentElement[2] = match2 + end + end + currentAttributeCt = currentAttributeCt + 1 + currentAttributes[currentAttributeCt] = currentAttribute + return true + end + end + + local function findCDATA() + first, last, match1 = find( xml, '^<!%[CDATA%[(.-)%]%]>', pos ) + if first then + finishText() + if self._call.text then self._call.text(match1) end + pos = last+1 + textStart = pos + return true + end + end + + local function closeElement() + first, last, match1 = find( xml, '^%s*(/?)>', pos ) + if first then + state = "text" + pos = last+1 + textStart = pos + + -- Resolve namespace prefixes AFTER all new/redefined prefixes have been parsed + if currentElement[3] then currentElement[2] = nsForPrefix(currentElement[3]) end + if self._call.startElement then self._call.startElement(unpack(currentElement)) end + if self._call.attribute then + for i=1,currentAttributeCt do + if currentAttributes[i][4] then currentAttributes[i][3] = nsForPrefix(currentAttributes[i][4]) end + self._call.attribute(unpack(currentAttributes[i])) + end + end + + if match1=="/" then + pop(nsStack) + if self._call.closeElement then self._call.closeElement(unpack(currentElement)) end + end + return true + end + end + + local function findElementClose() + first, last, match1, match2 = find( xml, '^</([%a_][%w_.-]*)%s*>', pos ) + if first then + nsURI = nil + for i=#nsStack,1,-1 do if nsStack[i]['!'] then nsURI = nsStack[i]['!']; break end end + else + first, last, match2, match1 = find( xml, '^</([%a_][%w_.-]*):([%a_][%w_.-]*)%s*>', pos ) + if first then nsURI = nsForPrefix(match2) end + end + if first then + finishText() + if self._call.closeElement then self._call.closeElement(match1,nsURI) end + pos = last+1 + textStart = pos + pop(nsStack) + return true + end + end + + while pos<#xml do + if state=="text" then + if not (findPI() or findComment() or findCDATA() or findElementClose()) then + if startElement() then + state = "attributes" + else + first, last = find( xml, '^[^<]+', pos ) + pos = (first and last or pos) + 1 + end + end + elseif state=="attributes" then + if not findAttribute() then + if not closeElement() then + stdnse.debug1("Was in an element and couldn't find attributes or the close.") + return + end + end + end + end + + if not anyElement then stdnse.debug1("Parsing did not discover any elements") end + if #nsStack > 0 then stdnse.debug1("Parsing ended with unclosed elements") end + end, + +} + +--- Parses xml and outputs a dom table. +-- @param xml the xml body to be parsed. +-- @param options if any to use. Supports <code>stripWhitespaces</code> currently. +function parseDOM (xml, options) + if not options then options={} end + local rich = not options.simple + local push, pop = table.insert, table.remove + local stack = {} + local doc = { type="document", name="#doc", kids={} } + local current = doc + local builder = parser:new{ + startElement = function(name,nsURI) + local el = { type="element", name=name, kids={}, el=rich and {} or nil, attr={}, nsURI=nsURI, parent=rich and current or nil } + if current==doc then + if doc.root then stdnse.debug2(("Encountered element '%s' when the document already has a root '%s' element"):format(name,doc.root.name)) return end + doc.root = el + end + push(current.kids,el) + if current.el then push(current.el,el) end + current = el + push(stack,el) + end, + attribute = function(name,value,nsURI) + if not current or current.type~="element" then stdnse.debug2(("Encountered an attribute %s=%s but I wasn't inside an element"):format(name,value)) return end + local attr = {type='attribute',name=name,nsURI=nsURI,value=value,parent=rich and current or nil} + if rich then current.attr[name] = value end + push(current.attr,attr) + end, + closeElement = function(name) + if current.name~=name or current.type~="element" then stdnse.debug2(("Received a close element notification for '%s' but was inside a '%s' %s"):format(name,current.name,current.type)) return end + pop(stack) + current = stack[#stack] + end, + text = function(value) + if current.type~='document' then + if current.type~="element" then stdnse.debug2(("Received a text notification '%s' but was inside a %s"):format(value,current.type)) return end + push(current.kids,{type='text',name='#text',value=value,parent=rich and current or nil}) + end + end, + comment = function(value) + push(current.kids,{type='comment',name='#comment',value=value,parent=rich and current or nil}) + end, + pi = function(name,value) + push(current.kids,{type='pi',name=name,value=value,parent=rich and current or nil}) + end + } + builder:parseSAX (xml,options) + return doc +end + +return _ENV; + |