#! /usr/bin/stap
# 
# Copyright (C) 2010 Free Software Foundation, Inc.
# 
# 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/>.

global opt_f
global opt_q

global trace
# FIXME: count()?
global trace_count
global last_tid
probe begin
{
  trace[target ()] = 1
  trace_count = 1
  last_tid = target ()
}

function heading:string ()
{
  if (trace_count > 1)
    {
      /* strace really calls TID a "pid".  */
      return sprintf ("[pid %5d] ", tid ())
    }
  else
    return ""
}

global namea

function destroy (tid:long)
{
  delete namea[tid]
}

function lhs:string (tid:long)
{
  return namea[tid]
}
probe end
{
  foreach (tid in namea)
    printf ("%s = ? <tracer terminated>\n", lhs (tid))
}

/* BUG: sleeping function called from invalid context at kernel/mutex.c:94
%{static DEFINE_MUTEX (tracer_mutex);%}
function lock ()
%{
  mutex_lock (&tracer_mutex);
%}
function unlock ()
%{
  mutex_unlock (&tracer_mutex);
%}
*/
global dummy
function lock () { dummy = 1; }
function unlock () { dummy = 1; }

#probe kprocess.start
#{
#  trace[pid ()] = 1
#  trace_count++
#}
#probe kprocess.exit
#{
#  trace[pid ()] = 0
#  trace_count--
#}
probe kprocess.create
{
  if (opt_f && trace[tid ()] != 0)
    {
      /* systemtap bug?  Why `new_pid' is provided but `new_tid' is not?  */
      new_tid = task_tid (task)
      trace[new_tid] = 1
      trace_count++
      if (!opt_q)
	printf ("Process %d attached\n", new_tid);
    }
}

probe kprocess.release
{
  /* systemtap bug?  Why `pid' is provided but `tid' is not?  */
  /* systemtap bug?  Why `[pt]id' is not called `released_[pt]id' to keep the
     naming in sync with kprocess.create?  */
  tid = task_tid (task)
  if (trace[tid] != 0)
    {
      if (namea[tid] != "")
	{
	  printf ("%s = ?\n", lhs (tid))
	  destroy (tid)
	}
# FIXME
      else if (0)
	{
	  /* systemtap bug?  exit_group(2) systemtap calls "exit" and _exit(2)
	     is not caught at all.  */
	  lock ()
	  if (last_tid != tid () && namea[last_tid] != "")
	    printf (" <unfinished ...>\n")
	  last_tid = tid
	  printf ("%s_exit(?) = ?\n", heading ())
	  unlock ()
	}
      delete trace[tid]
      trace_count--
      if (!opt_q)
	printf ("Process %d detached\n", tid);
    }
}
probe syscall.*
{
  if (trace[tid ()] != 0)
    {
      lock ()
      /* Why is mmap() called recursively twice?  */
      if (namea[last_tid] != "")
	printf (" <unfinished ...>\n")
      last_tid = tid ();
      namea[tid ()] = name
      printf ("%s%s(%s", heading (), name, argstr)
      unlock ()
    }
}
probe syscall.*.return
{
  if (trace[tid ()] != 0)
    {
      lock ()
      if (last_tid != tid () && namea[last_tid] != "")
	printf (" <unfinished ...>\n")
      if ((last_tid != tid () && namea[last_tid] != "")
          || (last_tid == tid () && namea[last_tid] == ""))
	printf ("%s<... %s resumed> ", heading (), name);
      last_tid = tid ();
      printf (") = %s\n", retstr)
      destroy (tid ())
      unlock ()
    }
}