#!/bin/bash
#
# stap-server	init.d script for the systemtap compile server
#
# chkconfig: - 00 99
# description: The systemtap compile server provides a centralized and secure \
#              environment for compiling systemtap scripts.
# config: /etc/sysconfig/stap-server
# config: /etc/stap-server/conf.d

BINDIR=@bindir@

# Source function library.
. /etc/rc.d/init.d/functions

# Systemtap function library
. $BINDIR/stap-env

prog=stap-server

# Commands
STAP_START_SERVER=$BINDIR/stap-start-server
STAP_STOP_SERVER=$BINDIR/stap-stop-server
UNAME=/bin/uname

# Path setup
CONFIG_FILE=/etc/sysconfig/stap-server
CONFIG_PATH=/etc/stap-server/conf.d
STAT_PATH=/var/run/stap-server
LOG_FILE=/var/log/stap-server.log

# Default Settings
STAP_USER=stap-server

# Default option settings
# Target architecture
OPT_KERNEL_ARCH=`stap_get_arch`
# A list of release_arch pairs
OPT_SERVER_LIST=
# Optional global config file
OPT_CONFIG_FILE=

echo_usage () {
  echo $"Usage: $prog {start|stop|restart|condrestart|try-restart|force-reload|status} [options]"
  echo $"Options:"
  echo $"	-c configfile	: specify additional config file"
  echo $"	-a arch		: change the target architecture"
  echo $"	-r release	: specify a kernel release"
  echo $"	-i		: specify all installed kernel releases"
  echo $""
  echo $"All options, except -c, may be specified more than once."
  echo $""
  echo $"Each -a option changes the target architecture for subsequent -r"
  echo $"options. The default is the architecture of the host platform."
  echo $""
  echo $"Each -r option specifies a server for the given kernel release and the"
  echo $"current architecture (either the default or set by the previous -a"
  echo $"option)."
  echo $""
  echo $"The -i option is a shortcut which specifies one server for each kernel"
  echo $"release installed in /lib/modules/. The default architecture is used"
  echo $"for these servers."
  echo $""
  echo $"The specified action is performed on each server specified on the command line."
  echo $"If no servers are specified on the command line, the behavior is as follows:"
  echo $""
  echo $"  start:        Start the servers configured in /etc/stap-server/conf.d/*.conf."
  echo $"                If none are configured, start a server for the kernel release"
  echo $"                and architecture of the host platform."
  echo $""
  echo $"  stop:         Stop all currently running servers."
  echo $""
  echo $"  restart:      Restart all currently running servers. If no servers are running,"
  echo $"                behave as if 'start' was specified."
  echo $""
  echo $"  condrestart:  Restart all currently running servers. If no servers are running,"
  echo $"                do nothing."
  echo $""
  echo $"  try-restart:  Same as condrestart."
  echo $""
  echo $"  force-reload: Stop all currently running servers and behave as if 'start'"
  echo $"                was specified."
  echo $""
  echo $"  status:       Report the status of all current running servers."
  echo $""
}

#-----------------------------------------------------------------
# Helper functions
#-----------------------------------------------------------------
log () { # message
  echo `LC_ALL=en date +"%b %e %T"`": $1" >> "$LOG_FILE"
}
clog () { # message [-n]
  echo $2 "$1"
  log "$1"
}
slog () { # message
  logger "$1" # if syslogd is running, this message will be sent to syslog.
  log "$1"
}
logex () { # command
  eval log \"Exec: $@\"
  "$@" >> "$LOG_FILE" 2>&1
  return $?
}
do_failure () { # message
  slog "Error: $1"
  failure "$1"
}
do_success () { # message
  log "Pass: $1"
  success "$1"
}

#------------------------------------------------------------------
# Parameter parsing and setup options
#------------------------------------------------------------------
parse_args () { # arguments
  local rc=0
  while [ -n "$1" ]; do
    case "$1" in
      -a)
	OPT_KERNEL_ARCH=$2
        shift 1
	;;
      -c)
        OPT_CONFIG_FILE=$2
        shift 1
        ;;
      -i)
	process_i
	;;
      -r)
	process_r $2
	test $? = 0 || rc=1
        shift 1
	;;
      --)
        ;;
      *)
	rc=1
        ;;
    esac
    shift 1
  done

  test $rc != 0 && echo_usage
  return $rc
}

# Process the -i flag.
process_i () {
  local save_arch=$OPT_KERNEL_ARCH
  OPT_KERNEL_ARCH=`stap_get_arch`

  cd /lib/modules
  local release
  for release in `ls`; do
    process_r $release
  done

  OPT_KERNEL_ARCH=$save_arch
  return 0
}

# Process the -r flag.
process_r () {
    local first_char=`expr "$1" : '\(.\).*'`

    if test "$first_char" = "/"; then # fully specified path
        local kernel_build_tree=$1
        local version_file_name="$kernel_build_tree/include/config/kernel.release"
        # The file include/config/kernel.release within the kernel
        # build tree is used to pull out the version information
	local kernel_release=`cat $version_file_name 2>/dev/null`
	if test "X$kernel_release" = "X"; then
	    echo "Missing $version_file_name"
	    return 1
	fi
	OPT_SERVER_LIST="$OPT_SERVER_LIST ${kernel_release}_${OPT_KERNEL_ARCH}"
	return 0
    fi

    # kernel release specified directly
    OPT_SERVER_LIST="$OPT_SERVER_LIST ${1}_${OPT_KERNEL_ARCH}"
    return 0
}

# Default to the currently running kernel release
get_release () { # server-spec
    if [ -z "$1" ]; then
	$UNAME -r
    else
	expr "$1" : '\(.*\)_.*'
    fi
}

# Default to the currently running kernel release
get_arch () { # server-spec
    if [ -z "$1" ]; then
	stap_get_arch
    else
	expr "$1" : '.*_\(.*\)'
    fi
}

load_config () {
  # Include configs
  if [ -f "$CONFIG_FILE" ]; then
    . "$CONFIG_FILE"
  fi
  if [ -f "$OPT_CONFIG_FILE" ]; then
    . "$OPT_CONFIG_FILE"
  fi
}

load_server_config () {
  CONFIG_OPTS=
  for f in "$CONFIG_PATH"/*.conf; do
    if [ -f "$f" ]; then
      # Obtain an architecture and release from each config file.
      # Ensure that we get the default architecture and release if they
      # are not specified.
      local ARCH=
      local RELEASE=
      . "$f"
      [ -z "$ARCH" ] && ARCH=`get_arch`
      [ -z "$RELEASE" ] && RELEASE=`get_release`
      CONFIG_OPTS="$CONFIG_OPTS -a $ARCH -r $RELEASE"
    fi
  done
}

prepare_stat_dir () {
  if [ ! -d "$STAT_PATH" ]; then
    logex mkdir -p "$STAT_PATH"
    [ $? -ne 0 ] && return 1
  fi
  return 0
}

stat_file () { # server-spec
    echo $STAT_PATH/$1
}

default_server_list () {
  echo "`get_release`_`get_arch`"
}

check_server_running () { # server-spec
  local server_status=`stat_file $1`
  test ! -f $server_status && return 1
  (ps -e | grep stap-serverd | grep -q `cat $server_status`) || return 1
  # Server is already running
  return 0
}

managed_servers () {
  if [ ! -d $STAT_PATH ]; then
      echo ""
      return 1
  fi
  cd $STAT_PATH
  local list=`ls`
  if [ -z "$list" ]; then
      echo ""
      return 1
  fi

  echo "$list"
}

start () { # server-list
  prepare_stat_dir
  if [ $? -ne 0 ]; then
    do_failure $"Failed to make stat directory ($STAT_PATH)"
    return 1
  fi

  # Start the specified servers
  local server_list="$1"
  # If none specified, start the configured servers
  if [ -z "$server_list" ]; then
    load_server_config
    parse_args $CONFIG_OPTS || exit 2
    server_list="$OPT_SERVER_LIST"

    # If none configured, start the default servers
    [ -z "$server_list" ] && server_list=`default_server_list`
  fi

  # Start each requested server in turn
  local rc=0
  local spec
  local first=1
  for spec in $server_list; do
      local release=`get_release $spec`
      local arch=`get_arch $spec`

      test $first = 0 && echo
      first=0
      clog $"Starting $prog for $release $arch: " -n

      # Is there already a server running for the requested kernel release
      # and arch?
      if check_server_running $spec; then
	  do_success $"$prog start for $release $arch"
	  continue
      fi

      # Start the server here.
      local server_status=`stat_file $spec`
      runuser -s /bin/bash - $STAP_USER -c "$STAP_START_SERVER -r $release -a $arch --log=$LOG_FILE" > $server_status
      if [ $? != 0 ]; then
	  rm -f $server_status
	  do_failure $"$prog start: unable to start stap-server for $release $arch"
	  rc=1
	  continue
      fi

      do_success $"$prog start for $release $arch"
  done

  return $rc
}

stop () { # server-list
  local server_status
  local server_list
  local first=1

  # Stop the specified servers or all servers, if none specified.
  server_list="$1"
  [ -z "$server_list" ] && server_list=`managed_servers`

  # No server specified or running?
  if [ -z "$server_list" ]; then
    clog $"Stopping $prog: " -n
    do_success $"$prog: No managed servers to stop"
    return 0
  fi

  # Stop each server in turn
  local rc=0
  for server_status in $server_list; do
      release_arch=`echo $server_status | sed 's/_/ /'`

      test $first = 0 && echo
      first=0
      clog $"Stopping $prog for $release_arch: " -n

      local this_rc=0
      local server_status_file=`stat_file $server_status`
      if check_server_running $server_status; then
	  local pid=`cat $server_status_file`
	  runuser -s /bin/bash - $STAP_USER -c "$STAP_STOP_SERVER $pid"
	  if [ $? != 0 ]; then
	      do_failure $"$prog start: unable to start stap-server for $release $arch"
	      this_rc=1
	      rc=1
	  fi
      fi
      if [ $this_rc = 0 ]; then
	  rm -f $server_status_file
	  do_success $"$prog stop for $release_arch"
      fi
  done

  return $rc
}

status () { # server-list
  local server_list
  local rc=0

  # Report status for the specified servers or all servers, if none specified.
  server_list="$1"
  [ -z "$server_list" ] && server_list=`managed_servers`

  # No server specified or running?
  if [ -z "$server_list" ]; then
      echo "No managed stap-server is running"
      return 3
  fi

  # Get status of each server in turn
  local server_status
  for server_status in $server_list; do
      local release_arch=`echo $server_status | sed 's/_/ /'`
      local server_status_file=`stat_file $server_status`
      if [ ! -f $server_status_file ]; then
	  echo "stap-server for $release_arch is not running"
	  rc=3
      else
	  local pid=`cat $server_status_file`
	  if check_server_running $server_status; then
	      echo "stap-server for $release_arch running as PID $pid"
	  else
	      echo "stap-server for $release_arch started as PID $pid is no longer running"
	      rm -f $server_status_file
	      rc=1
	  fi
      fi
  done

  return $rc
}

# Restart or start if not running
function restart () { # server-list
  local server_list

  # Restart the specified servers or all servers, if none specified.
  server_list="$1"
  [ -z "$server_list" ] && server_list=`managed_servers`

  # Stop the specified servers, or all if none specified
  stop "$server_list"
  local rc=$?
  echo

  # Restart the same servers. If none were specified then
  # start the configured or default server(s)).
  start "$server_list"
  local this_rc=$?
  [ $this_rc != 0 ] && rc=$this_rc

  return $rc
}

# Restart only if running
function condrestart () { # server-list
  local server_list

  # Restart the specified servers or all servers, if none specified,
  # but only if they are already running.
  server_list="$1"
  [ -z "$server_list" ] && server_list=`managed_servers`

  # No server specified or running?
  if [ -z "$server_list" ]; then
      clog "No managed stap-server is running" -n
      do_success "No managed stap-server is running"
      return 0
  fi

  # For each server in the list, stop it if it is running
  local rc=0
  local this_rc
  local start_list=
  local server_spec
  local first=1
  for server_spec in $server_list; do
    test $first = 0 && echo
    first=0

    if ! status $server_spec >/dev/null 2>&1; then
	local release=`get_release $server_spec`
	local arch=`get_arch $server_spec`
	clog $"$prog for $release $arch is not running" -n
	do_success "$prog for $release $arch is not running"
	continue
    fi

    start_list="$start_list $server_spec"

    stop "$server_spec"
    this_rc=$?
    [ $this_rc != 0 ] && rc=$this_rc
  done

  # Now restart the servers that were running
  for server_spec in $start_list; do
    echo
    start "$server_spec"
    local this_rc=$?
    [ $this_rc != 0 ] && rc=$this_rc
  done

  return $rc
}

#------------------------------------------------------------------
# Mainline script
#------------------------------------------------------------------
CMD=$1
shift 1
OPTS=`getopt -s bash -u -o 'a:c:ir:' -- $@`
if [ $? -ne 0 ]; then
  slog "Error: Argument parse error: $@"
  failure $"parse error"
  echo_usage
  exit 2
fi

parse_args $OPTS || exit 2
load_config

RETVAL=0

case $CMD in
  start)
  # Start specified servers. If none specified, start configured servers
  start "$OPT_SERVER_LIST"
  RETVAL=$?
  ;;
  stop)
  # Stop specified servers
  stop "$OPT_SERVER_LIST"
  RETVAL=$?
  ;;
  # Restart specified servers
  restart)
  restart "$OPT_SERVER_LIST"
  RETVAL=$?
  ;;
  # Restart specified servers if they are running
  condrestart|try-restart)
  condrestart "$OPT_SERVER_LIST"
  RETVAL=$?
  ;;
  # Give status on specified servers
  status)
  status "$OPT_SERVER_LIST"
  exit $?
  ;;
  # Reloading config without stop/restart is not supported
  reload)
  RETVAL=3
  ;;
  # Reload config with stop/start
  force-reload)
  # stop all running servers
  stop
  echo
  # Restart specified servers
  # If none specified, restart configured servers
  start "$OPT_SERVER_LIST"
  RETVAL=$?
  ;;
  usage|*)
  echo_usage
  RETVAL=0
  ;;
esac

echo
exit $RETVAL