#!/usr/bin/stap
#
# Copyright (C) 2008-2013 Red Hat, 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 2
# 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, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
#

# ===================================================================
# Do this when we have started
global report_period = 0
# For watch_forked variable:
#    0 = watch only main thread
#    1 = watch forked with same execname as well
#    2 = watch all forked processes
global watch_forked = 2
probe begin {
  if ($# == 1) {
    report_period = $1
  }
  print("Collecting data...\n")
  printf("... for pid %d - %s\n", target(), pid2execname(target()))
}

# ===================================================================
# Define helper function for printing results
function compute_score() {
  # new empirical formula that was proposed by Vratislav Podzimek <vpodzime@redhat.com> in his bachelor thesis
  return syscalls + (poll_timeout + epoll_timeout + select_timeout + itimer_timeout + nanosleep_timeout + futex_timeout + signal_timeout) * 4 + (reads + writes) / 5000 + (ifxmit + ifrecv) * 25
}

function print_status() {
  printf("-----------------------------------\n")
  ###target_set_report()
  printf("Monitored process: %d (%s)\n", target(), pid2execname(target()))
  printf("Number of syscalls: %d\n", syscalls)
  printf("Kernel/Userspace ticks: %d/%d (%d)\n", kticks, uticks, kticks+uticks)
  printf("Read/Written bytes (from/to devices): %d/%d (%d)\n", reads, writes, reads+writes)
  printf("Read/Written bytes (from/to N/A device): %d/%d (%d)\n", reads_c, writes_c, reads_c+writes_c)
  printf("Transmitted/Recived bytes: %d/%d (%d)\n", ifxmit, ifrecv, ifxmit+ifrecv)
  printf("Polling syscalls: %d\n", poll_timeout+epoll_timeout+select_timeout+itimer_timeout+nanosleep_timeout+futex_timeout+signal_timeout)
  printf("SCORE: %d\n", compute_score())
}

# ===================================================================
# Define helper function for comparing if this is relevant pid
# and for watching if our watched pid forked
# ... from http://sourceware.org/systemtap/wiki/systemtapstarters
global PIDS = 1   # as target() is already running
function is_watched(p) {
  if ( (watch_forked == 0 && p == target()) || (watch_forked == 1 && target_set_pid(p) && pid2execname(target()) == pid2execname(p)) || (watch_forked == 2 && target_set_pid(p)) ) {
    #printf("Process %d is relevant to process %d\n", p, target())
    return 1   # yes, we are watching this pid
  } else {
    return 0   # no, we are not watching this pid
  }
}
# Add a relevant forked process to the list of watched processes
probe kernel.function("do_fork") {
  #printf("Fork of %d (%s) detected\n", pid(), execname())
  if (is_watched(pid())) {
    #printf("Proces %d forked\n", pid())
    PIDS = PIDS + 1
    #printf("Currently watching %d pids (1 just added)\n", PIDS)
  }
}
# Remove pid from the list of watched pids and print report when
# all relevant processes ends
probe syscall.exit {
  if (is_watched(pid())) {
    #printf("Removing process %d\n", pid())
    PIDS = PIDS - 1
  }
  #printf("Currently watching %d pids (1 just removed)\n", PIDS)
  if (PIDS == 0) {
    printf("-----------------------------------\n")
    printf("LAST RESULTS:\n")
    print_status()
    exit()
  }
}

# ===================================================================
# Check all syscalls
# ... from syscalls_by_pid.stp
global syscalls
probe syscall.* {
  if (is_watched(pid())) {
    syscalls++
    #printf ("%s(%d) syscall %s\n", execname(), pid(), name)
  }
}

# ===================================================================
# Check read/written bytes
# ... from disktop.stp
global reads, writes, reads_c, writes_c
probe vfs.read.return {
  if (is_watched(pid()) && $return>0) {
    if (devname!="N/A") {
      reads += $return
    } else {
      reads_c += $return
    }
  }
}
probe vfs.write.return {
  if (is_watched(pid()) && $return>0) {
    if (devname!="N/A") {
      writes += $return
    } else {
      writes_c += $return
    }
  }
}

# ===================================================================
# Check kernel and userspace CPU ticks
# ... from thread-times.stp
global kticks, uticks
probe timer.profile {
  if (is_watched(pid())) {
    if (!user_mode())
      kticks++
    else
      uticks++
  }
}

# ===================================================================
# Check polling
# ... from timeout.stp
global poll_timeout, epoll_timeout, select_timeout, itimer_timeout
global nanosleep_timeout, futex_timeout, signal_timeout
global to
probe syscall.poll, syscall.epoll_wait {
  if (timeout) to[pid()]=timeout
}
probe syscall.poll.return {
  if ($return == 0 && is_watched(pid()) && to[pid()] > 0) {
    poll_timeout++
    delete to[pid()]
  }
}
probe syscall.epoll_wait.return {
  if ($return == 0 && is_watched(pid()) && to[pid()] > 0) {
    epoll_timeout++
    delete to[pid()]
  }
}
probe syscall.select.return {
  if ($return == 0 && is_watched(pid())) {
    select_timeout++
  }
}
probe syscall.futex.return {
  if ($return == 0 && is_watched(pid()) && errno_str($return) == "ETIMEDOUT") {
    futex_timeout++
  }
}
probe syscall.nanosleep.return {
  if ($return == 0 && is_watched(pid())) {
    nanosleep_timeout++
  }
}
probe kernel.function("it_real_fn") {
  if (is_watched(pid())) {
    itimer_timeout++
  }
}
probe syscall.rt_sigtimedwait.return {
   if (is_watched(pid()) && errno_str($return) == "EAGAIN") {
     signal_timeout++
   }
}

# ===================================================================
# Check network traffic
# ... from nettop.stp
global ifxmit, ifrecv
probe netdev.transmit {
  if (is_watched(pid()) && dev_name!="lo") {
    ifxmit += length
  }
}
probe netdev.receive {
  if (is_watched(pid()) && dev_name!="lo") {
    ifrecv += length
  }
}

# ===================================================================
# Print report each X seconds
global counter
probe timer.s(1) {
  if (report_period != 0) {
    counter++
    if (counter == report_period) {
      print_status()
      counter = 0
    }
  }
}

# ===================================================================
# Print quit message
probe end {
  printf("-----------------------------------\n")
  printf("LAST RESULTS:\n")
  print_status()
  printf("-----------------------------------\n")
  printf("QUITTING\n")
  printf("-----------------------------------\n")
}