local sig     = require "posix.signal"

local unistd  = require "posix.unistd"

local syswait = require "posix.sys.wait"

local function go (fn, ...)

  local cpid = unistd.fork ()

  if cpid == 0 then -- run function as child

    unistd._exit (fn (...) or 0)

  else

    return cpid

  end

end

local verbose = #arg > 0

local function sleepx (secs)

  while true do

    secs = unistd.sleep (secs)

    if verbose then print ("sleep", secs) end

    if secs == 0 then return end

  end

end

local nchild, nsig = 0, 0

sig.signal (sig.SIGCHLD, function()

  local pid, status, code = syswait.wait (-1, syswait.WNOHANG)

  while pid do

    if pid ~= 0 then

      if verbose then print ("wait", pid, status, code) end

      nchild = nchild + 1

    end

    pid, status, code = syswait.wait (-1, syswait.WNOHANG)

  end

end)

local function handler (signo)

  if verbose then print ("handled", signo) end

  nsig = nsig + 1

end

sig.signal (sig.SIGUSR1, handler)

sig.signal (sig.SIGUSR2, handler)

sig.signal (60, handler)

local function killp (nsig)

  return sig.kill (unistd.getppid (), nsig)

end

c1 = go (function() unistd.sleep (1); killp (sig.SIGUSR1); killp (sig.SIGUSR2) end)

c2 = go (function() unistd.sleep (2); killp (sig.SIGUSR2); end)

c3 = go (function() unistd.sleep (2); killp (sig.SIGUSR1) end)

sleepx(3)

if verbose then

  print ("children", nchild, "signals", nsig)

else

  assert (nchild == 3)

  assert (nsig ==  4)

  print '+++ tests OK +++'

end