initial commit

2024-11-28 01:20:55 +08:00 · 2023-07-25 14:20:52 +08:00 · 2023-07-25 14:20:52 +08:00 · 5782bd8c90
commit 5782bd8c90
1 changed files with 104 additions and 0 deletions
--- a/demo.lua
+++ b/demo.lua
@ -0,0 +1,104 @@
+#! /usr/local/bin/lua54
+
+print("Content-Type: text/html\r\n\r\n")
+
+print[[
+<!DOCTYPE html>
+<HTML>
+<HEAD>
+<TITLE>Lua: demo</TITLE>
+<LINK REL="stylesheet" TYPE="text/css" HREF="https://lua.org/lua.css">
+<META HTTP-EQUIV="content-type" CONTENT="text/html; charset=utf-8">
+<STYLE TYPE="text/css">
+textarea {
+	font-family: monospace ;
+}
+
+input {
+	margin-right: 1em ;	
+}
+</STYLE>
+</HEAD>
+
+<BODY>
+
+<H1>
+<A HREF="https://lua.org/home.html"><IMG SRC="https://lua.org/images/logo.gif" ALT="Lua"></A>
+Demo
+</H1>
+
+<FORM ACTION="/demo.lua" METHOD="POST">
+<TEXTAREA ROWS="16" COLS="72" NAME="input" maxlength="2000">]]
+
+-- demo.lua
+-- run user programs in constrained environment
+
+local T,E,I
+
+-- convert input  to plain text
+T=io.read"*a"
+T=string.match(T,"=(.-)$") or ""
+T=string.gsub(T,"+"," ")
+T=string.gsub(T,"%%(%x%x)",function (x) return string.char(tonumber(x,16)) end)
+T=string.gsub(T,"^%s*=%s*","return ")
+
+-- save functions needed at the end
+local _G=_G
+local collectgarbage=collectgarbage
+local pack=table.pack
+local print=print
+local tostring=tostring
+local unpack=table.unpack
+local write=io.write
+
+-- continue HTML began in shell script
+write(T)
+write[[</TEXTAREA>
+<P>
+<INPUT TYPE="submit" VALUE="run">
+<INPUT TYPE="button" VALUE="clear" onclick="this.form.elements['input'].value=''">
+<INPUT TYPE="reset" VALUE="restore">
+<INPUT TYPE="button" VALUE="restart" onclick="window.location.href='/demo.lua'">
+</FORM>
+
+<H2>Output</H2>
+<TEXTAREA ROWS="8" COLS="72">]]
+io.flush()
+
+-- delete unsafe functions
+arg=nil
+debug.debug=nil
+debug.getfenv=getfenv
+debug.getregistry=nil
+dofile=nil
+io={write=io.write}
+loadfile=nil
+os.execute=nil
+os.getenv=nil
+os.remove=nil
+os.rename=nil
+os.tmpname=nil
+package.loaded.io=io
+package.loaded.package=nil
+package=nil
+require=nil
+
+-- run program in global environment
+T,E=load(T,"=input","t")
+if not T then
+	print(E)	E="failed to compile"	I="alert"
+else
+	T=pack(pcall(T))
+	_G.tostring=tostring
+	if not T[1] then
+		print(T[2])	E="failed to run"	I="alert"
+	else
+		print(unpack(T,2,T.n))	E="ran successfully"	I="ok"
+	end
+	collectgarbage()
+end
+
+-- continue HTML
+write('</TEXTAREA><P><IMG SRC="https://lua.org/images/',I,'.png" ALIGN="absbottom">\n')
+write('Your program ',E,'.\n')
+