This file is indexed.

/usr/share/lua/5.2/luxio/event.lua is in lua-luxio0 8-1.

This file is owned by root:root, with mode 0o644.

The actual contents of the file can be viewed below.

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
-- Light Unix I/O for Lua
-- Copyright 2012 Daniel Silverstone <dsilvers@digital-scurf.org>
--
-- Distributed under the same terms as Lua itself (MIT).
--
-- A low-ish level event-based main-loop for luxio-based programs
-------------------------------------------------------------------------------
--
-- ev = require "luxio.event"
--
-- ev.register_fd(fd, ctx, input_available, output_space, error_event)
--    Register a FD with the poll loop
--                fd is the FD to be registered (should be a FD number)
--                ctx is the context to be passed to the callbacks
--                input_available is the callback for when POLLIN is active
--                                want_more = input_available(ctx, fd, urgent)
--                                urgent is true if POLLPRI was set.
--                output_space is the callback for when POLLOUT is active
--                                have_more = output_space(ctx, fd)
--                error_event is the callback for when POLLERR, POLLNVAL,
--                            or POLLHUP happens.
--                                error_event(ctx, fd, "hup" or "nval" or "err")
--
--    If the callback returns true then the event is re-armed, otherwise
--    you will need to call ev.set_events() later to re-arm the event.
--    The error event cannot be disarmed and is the only event armed
--    when you register a FD.  If the error event is called then the event
--    system will unregister the FD on return from the handler if the handler
--    has not unregistered it itself.
--
-- ev.unregister_fd(fd)
--    Removes a FD from the poll loop
--
-- ev.set_events(fd, input_enabled, output_enabled)
--    Arm/Disarm events for fd.
--               fd is the FD registered with ev.register_fd
--               input_enabled is whether to arm the input event (POLLIN)
--               output_enabled is whether to arm the output event (POLLOUT)
--    If the respective enable is true the event is armed, if it is
--    false then it's disarmed.  If you pass nil for the enable then the
--    current arm/disarm state is unchanged.
--
-- res = ev.step(timeout)
--    Runs one step of the poll loop, returning after timeout milliseconds
--    if nothing happened.
--               timeout is the number of milliseconds to run for.
--                       -1 means 'forever'
--    Returns the number of FDs whose events fired, or 0 if timed out.
--
-- handle = ev.timer(timeout, timer_event, ctx)
--    Call timer_event(ctx) after timeout milliseconds.
--    if the event returns true, re-arms the timer automatically.
--
-- handle = ev.alarm(wallclock, timer_event, ctx)
--    Call timer_event at (or soon after) wallclock (expressed as time_t)
--    If the event returns a number, treat that as a time_t and
--    re-arm the alarm.
--
-- ev.cancel_timer(handle)
--    Cancel the timer or alarm associated with the provided handle.
--
-- ... = ev.run()
--    Runs the poll loop until it is terminated by ev.quit().
--    Returns the values passed to ev.quit()
--
-- ev.quit(...)
--    Causes ev.run() to return to the caller, with the given values as
--    the return values.  Note that this makes no sense unless you use
--    the ev.run() wrapper.
--
-- The event system runs all event callbacks inside a pcall but ignored errors.

local l = require "luxio"

local pollfds_new = l.pollfds_new
local pollfds_resize = l.pollfds_resize
local pollfds_getslot = l.pollfds_getslot
local pollfds_setslot = l.pollfds_setslot

local bor = l.bit.bor
local bclear = l.bit.bclear
local btest = l.bit.btest

local poll = l.poll
local strerror = l.strerror

local pfds = pollfds_new()
local extend_by = 10
local gaps = {}
local fds = {}

local POLLIN = l.POLLIN
local POLLOUT = l.POLLOUT
local POLLPRI = l.POLLPRI
local POLLERR = l.POLLERR
local POLLHUP = l.POLLHUP
local POLLNVAL = l.POLLNVAL
local input_bits = bor(POLLIN, POLLPRI)

local zero_timeval = l.zero_timeval
local gettimeofday = l.gettimeofday

l = nil

local quitvals
local quit_error = {}

local _nval = "nval"
local _hup = "hup"
local _err = "err"

local function _claim_free_slot()
   -- Find a free slot in the pollfds
   local gap = next(gaps)
   if gap then
      gaps[gap] = nil
      return gap
   end
   -- No gaps in the pollfds, so extend
   pollfds_resize(pfds, #pfds + extend_by)
   -- Store the new gaps for later
   for n = #pfds - (extend_by - 2), #pfds do
      gaps[n] = true
   end
   -- And return the one gap we didn't store
   return #pfds - (extend_by - 1)
end

local function _set_events(_fd, input_enable, output_enable)
   local fd = _fd
   if type(_fd) == "table" then
      fd = _fd.fd
   end
   local fdt = fds[fd]
   assert(fdt, "File descriptor '" .. tostring(_fd) .. "' is not registered")

   local events = fdt.events
   
   if input_enable then
      events = bor(events, input_bits)
   elseif input_enable == false then
      events = bclear(events, input_bits)
   end
   if output_enable then
      events = bor(events, POLLOUT)
   elseif output_enable == false then
      events = bclear(events, POLLOUT)
   end
   pollfds_setslot(pfds, fds[fd].slotnr, fd, events, 0)
   fdt.events = events
end

local function _null_evt() end
local function _register_fd(_fd, ctx, input_evt, output_evt, error_evt)
   local fd = _fd
   if type(_fd) == "table" then
      fd = _fd.fd
   end
   assert(fds[fd] == nil, "File descriptor '" .. tostring(_fd) .. "' is already registered")
   local fdt = {
      fd = fd,
      _fd = _fd,
      ctx = ctx,
      input_evt = input_evt or _null_evt,
      output_evt = output_evt or _null_evt,
      error_evt = error_evt or _null_evt,
      slotnr = _claim_free_slot(),
      events = 0
   }
   fds[fd] = fdt
   _set_events(_fd)
end

local function rpcall(...)
   local t = {pcall(...)}
   if not t[1] then
      print("Error during event handling:", t[2])
   end
   return unpack(t)
end
-- Uncomment this to disable error reporting
-- rpcall = pcall

local function _unregister_fd(_fd)
   if type(_fd) == "table" then
      fd = _fd.fd
   end
   local fdt = fds[fd]
   assert(fdt, "File descriptor '" .. tostring(_fd) .. "' is not registered")
   -- pull this fd out of poll
   pollfds_setslot(pfds, fdt.slotnr, -1, 0, 0)
   -- hand the slot back to the gap tracker
   gaps[fdt.slotnr] = true
   -- and unregister the fd from the list
   fds[fd] = nil
end

local function _step(timeout)
   local nfds, err = poll(pfds, timeout)
   if nfds == -1 then
      error(strerror(err))
   end
   local fds_to_process = nfds
   for slot = 1, #pfds do
      if fds_to_process == 0 then
	 break
      end
      local fd, ev, rev = pollfds_getslot(pfds, slot)
      local fdt = fds[fd]
      local cev = 0
      if fd >= 0 and rev ~= 0 then
	 -- Deal with errors first
	 local did_error = false
	 if btest(rev, POLLNVAL) then
	    -- fd is invalid, let the caller know
	    did_error = true
	    rpcall(fdt.error_evt, fdt.ctx, fd, _nval)
	 elseif btest(rev, POLLERR) then
	    -- fd errored
	    did_error = true
	    rpcall(fdt.error_evt, fdt.ctx, fd, _err)
	 elseif btest(rev, POLLHUP) then
	    -- fd HUPped
	    did_error = true
	    rpcall(fdt.error_evt, fdt.ctx, fd, _hup)
	 end
	 if did_error then
	    if fds[fd] then
	       _unregister_fd(fd)
	    end
	 else
	    -- No error, process incoming data first.
	    if btest(rev, POLLPRI) then
	       local ok, want = rpcall(fdt.input_evt, fdt.ctx, fdt._fd, true)
	       if ok and not want then
		  cev = bor(cev, input_bits)
	       end
	    elseif btest(rev, POLLIN) then
	       local ok, want = rpcall(fdt.input_evt, fdt.ctx, fdt._fd, false)
	       if ok and not want then
		  cev = bor(cev, input_bits)
	       end
	    end
	    -- Now if we're still registered, process write space
	    if fds[fd] and btest(rev, POLLOUT) then
	       local ok, want = rpcall(fdt.output_evt, fdt.ctx, fdt._fd)
	       if ok and not want then
		  cev = bor(cev, POLLOUT)
	       end
	    end
	 end
	 fds_to_process = fds_to_process - 1
	 if fds[fd] then
	    -- rearm appropriate events
	    pollfds_setslot(pfds, slot, fd, bclear(fds[fd].events, cev), 0);
	 end
      end
   end
   return nfds
end

local events = nil
local event_handles = {}
local _timer = "timer"
local _alarm = "alarm"

local function _msecs_to_timeval(msecs)
   local z = zero_timeval()
   z.useconds = msecs * 1000
   return z
end

local function _time_t_to_timeval(time_t)
   local z = zero_timeval()
   z.seconds = time_t
   return z
end

local function _insert_timer_event(tmr)
   if events == nil then
      events = tmr
      return
   end
   local evt, pevt = events
   while (evt and (evt.when < tmr.when)) do
      pevt = evt
      evt = evt.next
   end

   if evt == events then
      -- tmr is now earliest
      tmr.next = events
      tmr.next.prev = tmr
      events = tmr
      return
   end

   if evt == nil then
      -- tmr is now latest
      tmr.prev = pevt
      pevt.next = tmr
      return
   end
      
   -- tmr is to be inserted just before evt
   tmr.prev = pevt
   tmr.next = evt

   tmr.next.prev = tmr
   tmr.prev.next = tmr
end

local function _remove_timer_event(tmr)
   if tmr.prev == nil then
      events = tmr.next
      if tmr.next then
	 tmr.next.prev = nil
      end
   else
      tmr.prev.next = tmr.next
      if tmr.next then
	 tmr.next.prev = tmr.prev
      end
   end
   tmr.next, tmr.prev = nil, nil
end

local function _timer(timeout, handler, ctx)
   local handle = {}
   timeout = _msecs_to_timeval(timeout)
   local tmr = {
      type = _timer,
      timeout = timeout,
      handler = handler,
      ctx = ctx,
      when = gettimeofday() + timeout,
      handle = handle
   }
   _insert_timer_event(tmr)
   event_handles[handle] = tmr
   return handle
end

local function _alarm(wallclock, handler, ctx)
   local handle = {}
   local tmr = {
      type = _alarm,
      handler = handler,
      ctx = ctx,
      when = _time_t_to_timeval(wallclock),
      handle = handle
   }
   _insert_timer_event(tmr)
   event_handles[handle] = tmr
   return handle
end

local function _cancel_timer(handle)
   local tmr = event_handles[handle]
   assert(tmr, "Unknown handle passed to luxio.event.cancel_timer()")
   _remove_timer_event(tmr)
   event_handles[handle] = nil
end

local function _run()
   repeat
      local timeout = -1
      if events then
	 local now = gettimeofday()
	 timeout = ((events.when - now).useconds)/1000
      end
      _step(timeout)
      local fnow = gettimeofday()
      while events and events.when < fnow do
	 local evt = events
	 _remove_timer_event(evt)
	 local ok, ret = pcall(evt.handler, evt.ctx)
	 if ok and ret then
	    if evt.type == _timer then
	       evt.when = fnow + evt.timeout
	    elseif evt.type == _alarm then
	       evt.when = _time_t_to_timeval(ret)
	    else
	       error("Unknown time event type: " .. tostring(evt.type))
	    end
	    _insert_timer_event(evt)
	 end
      end
   until quitvals
   return unpack(quitvals)
end

local function _quit(...)
   quitvals = {...}
   error(quit_error)
end

return {
   register_fd = _register_fd,
   unregister_fd = _unregister_fd,
   set_events = _set_events,
   step = _step,
   run = _run,
   quit = _quit,

   -- Magic values passed to error_event
   nval = _nval,
   hup = _hup,
   err = _err,

   -- Timer related maguffins
   timer = _timer,
   alarm = _alarm,
   cancel_timer = _cancel_timer
}