# -*- shell-script -*- # Signal handling routines # # Copyright (C) 2002, 2003, 2004, 2006, 2007, 2008, 2010, 2011 # Rocky Bernstein # # 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, 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; see the file COPYING. If not, write to # the Free Software Foundation, 59 Temple Place, Suite 330, Boston, # MA 02111 USA. # ==================== VARIABLES ======================================= # The "set" options in effect ($-) before debugger was invoked. typeset _Dbg_old_setopts # Place to save debugged program's exit handler, if any. typeset _Dbg_old_EXIT_handler='' typeset -i _Dbg_QUIT_ON_QUIT=0 # Return code that debugged program reports typeset -i _Dbg_program_exit_code=0 ############################################################ ## Signal arrays: These are indexed by the signal number. ## ############################################################ # Should we print that a signal was intercepted? # Each entry is "print" or "noprint" or null. typeset -a _Dbg_sig_print; _Dbg_sig_print=() # Should we reentry the debugger command loop on receiving the signal? # Each entry is "stop" or "nostop" or null. typeset -a _Dbg_sig_stop; _Dbg_sig_stop=() # Should we show a traceback on receiving the signal? # Each entry is "stack" or "nostack" or null. typeset -a _Dbg_sig_show_stack; _Dbg_sig_show_stack=() # Should pass the signal to the user program?? # Each entry is the trap handler with some variables substituted. typeset -a _Dbg_sig_passthrough; _Dbg_sig_passthrough=() # Should pass the signal to the user program?? # Each entry is the trap handler with some variables substituted. typeset -i _Dbg_return_level=0 # Place to save values of $1, $2, etc. typeset -a _Dbg_arg; _Dbg_arg=() # Save value of handler variable _Dbg_old_$sig _Dbg_save_handler() { typeset -r sig=$1 typeset old_handler='' old_handler_test=$(trap -p $sig) if [[ -n $old_handler ]] ; then typeset -a old_hand_a old_hand_a=($old_handler) old_handler=$(_Dbg_subst_handler_var ${old_hand_a[2]}) typeset -r decl_cmd="typeset -r _Dbg_old_${sig}_handler='$old_handler'" eval $decl_cmd fi } # Adjust handler variables to take into account the fact that when we # call the handler we will have added another call before the user's # handler. _Dbg_subst_handler_var() { typeset -i i typeset result='' for arg in $* ; do case $arg in '$LINENO' ) arg='${BASH_LINENO[0]}' ;; '${BASH_SOURCE[0]}' ) arg='${BASH_SOURCE[1]}' ;; '${FUNCNAME[0]}' ) arg='${FUNCNAME[1]}' ;; '${BASH_LINENO[0]}' ) arg='${BASH_LINENO[1]}' ;; esac if [[ $result == '' ]] ; then result=$arg else result="$result $arg" fi done echo $result } # Debugger exit handler. Don't really exit - but go back the debugger # command loop _Dbg_exit_handler() { # Consider putting the following line(s) in a routine. # Ditto for the restore environment typeset -i _Dbg_debugged_exit_code=$? # Turn off line and variable trace listing; allow unset parameter expansion. set +x +v +u if [[ ${_Dbg_sig_print[0]} == "print" ]] ; then # Note: use the same message that gdb does for this. _Dbg_msg "Program received signal EXIT (0)..." if [[ ${_Dbg_sig_show_stack[0]} == "showstack" ]] ; then _Dbg_do_backtrace 0 fi fi if [[ $_Dbg_old_EXIT_handler != '' ]] ; then eval $_Dbg_old_EXIT_handler fi # If we've set the QUIT signal handler not to stop, or we've in the # middle of leaving so many (subshell) levels or we have set to # leave quietly on termination, then do it! if [[ ${_Dbg_sig_stop[0]} != "stop" ]] \ || (( _Dbg_QUIT_LEVELS != 0 )) \ || (( _Dbg_QUIT_ON_QUIT )) ; then _Dbg_do_quit # We don't return from here. fi # We've tested for all the quitting conditions above. # Even though this is an exit handler, don't exit! typeset term_msg="normally" if [[ $_Dbg_debugged_exit_code != 0 ]] ; then term_msg="with code $_Dbg_debugged_exit_code" fi # If we tried to exit from inside a subshell, we only want to enter # the command loop if don't have any pending subshells. if (( BASH_SUBSHELL == 0 )) ; then _Dbg_msg \ "Debugged program terminated $term_msg. Use q to quit or R to restart." _Dbg_running=0 while : ; do _Dbg_process_commands done fi } # Generic signal handler. We consult global array _Dbg_sig_* for how # to handle this signal. # Since the command loop may be called we need to be careful about # using variable names that would be exposed to the user. _Dbg_sig_handler() { # Consider putting the following line(s) in a routine. # Ditto for the restore environment typeset -i _Dbg_debugged_exit_code=$? _Dbg_old_set_opts=$- # Turn off line and variable trace listing if were not in our own debug # mode, and set our own PS4 for debugging inside the debugger (( !_Dbg_set_debug )) && set +x +v +u shopt -s extdebug # This is the signal number. E.g. 15 is SIGTERM typeset -r -i _Dbg_signum=$1 if [[ ${_Dbg_sig_print[$_Dbg_signum]} == "print" ]] || \ [[ ${_Dbg_sig_stop[$_Dbg_signum]} == "stop" ]] ; then typeset -r name=$(_Dbg_signum2name $_Dbg_signum) # Note: use the same message that gdb does for this. _Dbg_msg "Program received signal $name ($_Dbg_signum)..." if [[ ${_Dbg_sig_show_stack[$_Dbg_signum]} == "showstack" ]] ; then _Dbg_stack_pos=0 ((_Dbg_stack_size = ${#FUNCNAME[@]})) _Dbg_do_backtrace fi fi if [[ ${_Dbg_sig_stop[$_Dbg_signum]} == "stop" ]] ; then ### The below duplicates what is above in _Dbg_debug_trap handler ### Should put common stuff into a function. shift # signum _Dbg_save_args "$@" _Dbg_set_debugger_entry _Dbg_hook_enter_debugger 'on receiving a signal' 'noprint' return $_Dbg_continue_rc elif (( _Dbg_sig_old_handler[_Dbg_signum] )) ; then eval ${_Dbg_sig_old_handler[$_Dbg_signum]} fi _Dbg_set_to_return_from_debugger 1 return $_Dbg_debugged_exit_code } _Dbg_err_handler() { if [[ $_Dbg_old_ERR_handler != '' ]] ; then eval $_Dbg_old_ERR_handler fi _Dbg_msg "Error occured at ${BASH_SOURCE[1]}:${BASH_LINENO[1]}" _Dbg_process_commands } # Echo the name for a given signal number $1. The resulting name # is in _Dbg_return _Dbg_signum2name() { typeset -i -r signum=$1; builtin kill -l $signum 2>/dev/null return $? } # Return the signal number for a given signal name $1. The resulting number # is in _Dbg_return _Dbg_name2signum() { typeset -r signame=$1; builtin kill -l $signame 2>/dev/null return $? } _Dbg_subexit_handler() { # Read in the journal to pick up variable settings that might have # been left from a subshell. if [[ ${FUNCNAME[1]} == _Dbg_* ]] && (( !_Dbg_set_debug )); then return 0 fi _Dbg_source_journal if (( _Dbg_QUIT_LEVELS > 0 )) ; then _Dbg_do_quit $_Dbg_debugged_exit_code fi } # Set up generic trap handler. Arguments are: # NAME print showstack stop passthrough _Dbg_init_trap() { typeset -r name=$1 typeset -i -r signum=$(_Dbg_name2signum $name) _Dbg_sig_print[$signum]=$2; _Dbg_sig_show_stack[$signum]=$3; _Dbg_sig_stop[$signum]=$4; # Work out passthrough later... # if [[ $5 == "pass*" ]] ; then # get existing trap from env. # _Dbg_sig_show_passthrough[$signum]=....; # if (( signum == 0 )) ; then trap '_Dbg_exit_handler "$BASH_COMMAND"' EXIT else typeset trap_cmd="trap '_Dbg_sig_handler $signum \"\$BASH_COMMAND\" \"\$@\"' $name" eval $trap_cmd fi } _Dbg_init_default_traps() { _Dbg_init_trap EXIT "noprint" "nostack" "stop" _Dbg_init_trap ILL "print" "showstack" "stop" _Dbg_init_trap INT "print" "showstack" "stop" _Dbg_init_trap QUIT "print" "showstack" "stop" _Dbg_init_trap TERM "print" "showstack" "stop" _Dbg_init_trap TRAP "print" "showstack" "stop" }