💾 Archived View for gemini.conman.org › sourcecode › Lua › GLV-1 › cgi.lua captured on 2021-12-03 at 14:04:38.
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-- ************************************************************************
--
-- CGI interface.
-- Copyright 2019 by Sean Conner. All Rights Reserved.
--
-- This program is free software: you can redistribute it and/or modify
-- it under the terms of the GNU General Public License as published by
-- the Free Software Foundation, either version 3 of the License, or
-- (at your option) any later version.
--
-- This program is distributed in the hope that it will be useful,
-- but WITHOUT ANY WARRANTY; without even the implied warranty of
-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-- GNU General Public License for more details.
--
-- You should have received a copy of the GNU General Public License
-- along with this program. If not, see <http://www.gnu.org/licenses/>.
--
-- Comments, questions and criticisms can be sent to: sean@conman.org
--
-- ************************************************************************
-- luacheck: ignore 611
-- RFC-3875
local syslog = require "org.conman.syslog"
local errno = require "org.conman.errno"
local fsys = require "org.conman.fsys"
local process = require "org.conman.process"
local exit = require "org.conman.const.exit"
local ios = require "org.conman.net.ios"
local nfl = require "org.conman.nfl"
local lpeg = require "lpeg"
local io = require "io"
local string = require "string"
local coroutine = require "coroutine"
local uurl = require "GLV-1.url-util"
local gi = require "GLV-1.gateway"
local tonumber = tonumber
local DEVNULI = io.open("/dev/null","r")
local DEVNULO = io.open("/dev/null","w")
-- ************************************************************************
-- Handle script command line arguments per RFC-3875 section 4.4
-- ************************************************************************
local parse_cgi_args do
local xdigit = lpeg.locale().xdigit
local char = lpeg.P"%" * lpeg.C(xdigit * xdigit)
/ function(c)
return string.char(tonumber(c,16))
end
+ (lpeg.R"!~" - lpeg.S' #%<>[\\]^{|}"=&+')
local args = lpeg.Cs(char^1) * lpeg.P"+"^-1
parse_cgi_args = lpeg.Ct(args^1) * lpeg.P(-1)
end
-- ************************************************************************
local function fdtoios(fd)
local newfd = ios()
newfd.__fd = fd
newfd.__co = coroutine.running()
newfd.close = function(self)
nfl.SOCKETS:remove(fd)
self.__fd:close()
return true
end
newfd._refill = function()
return coroutine.yield()
end
nfl.SOCKETS:insert(fd,'r',function(event)
if event.read then
local data,err = fd:read(8192)
if data then
if #data == 0 then
nfl.SOCKETS:remove(fd)
newfd._eof = true
end
nfl.schedule(newfd.__co,data)
else
if err ~= errno.EAGAIN then
syslog('error',"fd:read() = %s",errno[err])
end
end
else
newfd._eof = true
nfl.SOCKETS:remove(fd)
nfl.schedule(newfd.__co)
end
end)
return newfd
end
-- ************************************************************************
return function(auth,program,directory,base,location,out)
local gconf = require "CONF".cgi
local hconf = require "CONF".hosts[location.host].cgi
local dconf = directory.cgi
-- ------------------------------------------------------------------------
-- If the cgi block is not defined for the server, nor for a host, and we
-- get here, then there's been a misconfiguration. Report the error. The
-- other case is when the host has explicitely set 'cgi = false', in which
-- case, that host is opting out of CGI support entirely, so report the
-- error in that case too.
-- ------------------------------------------------------------------------
if not gconf and not hconf and not dconf then
syslog('error',"CGI script called, but CGI not configured!")
out:write("40\r\n")
return 40
end
if dconf == false
or hconf == false and dconf == nil then
syslog('error',"CGI script called, but CGI not configured!")
out:write("40\r\n")
return 40
end
local pipe,err1 = fsys.pipe()
if not pipe then
syslog('error',"CGI pipe: %s",errno[err1])
out:write("40\r\n")
return 40
end
pipe.read:setvbuf('no') -- buffering kills the event loop
local child,err = process.fork()
if not child then
syslog('error',"process.fork() = %s",errno[err])
out:write("40\r\n")
return 40
end
-- =========================================================
-- The child runs off to do its own thang ...
-- =========================================================
if child == 0 then
fsys.redirect(DEVNULI,io.stdin)
fsys.redirect(pipe.write,io.stdout)
fsys.redirect(DEVNULO,io.stderr)
-- -----------------------------------------------------------------
-- Close file descriptors that aren't stdin, stdout or stderr. Most
-- Unix systems have dirfd(), right? Right? And /proc/self/fd,
-- right? Um ... erm ...
-- -----------------------------------------------------------------
local dir = fsys.opendir("/proc/self/fd")
if dir and dir._tofd then
local dirfh = dir:_tofd()
for file in dir.next,dir do
local fh = tonumber(file)
if fh > 2 and fh ~= dirfh then
fsys._close(fh)
end
end
-- ----------------------------------------------------------
-- if all else fails, at least close these to make this work
-- ----------------------------------------------------------
else
DEVNULI:close()
DEVNULO:close()
pipe.write:close()
pipe.read:close()
end
local args = parse_cgi_args:match(location.query or "") or {}
local env = gi.setup_env(auth,program,base,location,directory,'cgi',hconf,gconf)
local prog do
if program:match "^/" then
prog = uurl.rm_dot_segs:match(program)
else
prog = uurl.rm_dot_segs:match(fsys.getcwd() .. "/" .. program)
end
end
local okay,err2 = fsys.chdir(directory.directory)
if not okay then
syslog('error',"CGI cwd(%q) = %s",directory.directory,errno[err2])
process.exit(exit.CONFIG)
end
process.exec(prog,args,env)
process.exit(exit.OSERR)
end
-- =========================================================
-- Meanwhile, back at the parent's place ...
-- =========================================================
pipe.write:close()
local inp = fdtoios(pipe.read)
local status = gi.handle_output(out,inp,program)
inp:close()
local info,err2 = process.wait(child)
if not info then
syslog('error',"process.wait() = %s",errno[err2])
return status
end
if info.status == 'normal' then
if info.rc ~= 0 then
syslog('warning',"program=%q status=%d",program,info.rc)
end
else
syslog('error',"program=%q status=%s description=%s",program,info.status,info.description)
end
return status
end