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# bashdb.fns - Bourne-Again Shell Debugger functions
_BUFSIZ=100
# Here after each statement in script being debugged.
# Handle single-step and breakpoints.
_steptrap() {
let _curline=$1-1 # no. of line that just ran
let "$_curline < 1" && let _curline=1
let "$_curline > $_firstline+$_BUFSIZ" && _readin $_curline
let " $_trace" &&
_msg "$PS4, line $_curline: ${_lines[$(($_curline-$_firstline+1))]}"
# if in step mode, decrement counter
let " $_steps >= 0" && let _steps="$_steps - 1"
# first check if line num or string brkpt. reached
if _at_linenumbp || _at_stringbp; then
_msg "Reached breakpoint at line $_curline"
_cmdloop # enter debugger
# if not, check whether break condition exists and is true
elif [ -n "$_brcond" ] && eval $_brcond; then
_msg "Break condition $_brcond true at line $_curline"
_cmdloop # enter debugger
# next, check if step mode and no. of steps is up
elif let "$_steps == 0"; then
_msg "Stopped at line $_curline"
_cmdloop # enter debugger
fi
}
# Debugger command loop.
# Here at start of debugger session, when brkpt. reached, or after single-step.
_cmdloop() {
local cmd args
# added support for default command (last one entered)
while read -e -p "bashdb> [$lastcmd $lastargs] " cmd args; do
if [ -z "$cmd" ]; then
cmd=$lastcmd
args=$lastargs
fi
lastcmd="$cmd"
lastargs=$args
# made commands to be debugger commands by default, no need for '*' prefix
case $cmd in
bp ) _setbp $args ;; #set brkpt at line num or string
bc ) _setbc $args ;; # set break condition
cb ) _clearbp ;; # clear all brkpts.
g ) return ;; # start/resume execution
s ) let _steps=${args:-1}
return ;; # single-step N times(default 1)
x ) _xtrace ;; # toggle execution trace
pr ) _print $args ;; # print lines in file
\? | h | help ) _menu ;; # print command menu
hi ) history ;; # show command history
q ) _cleanup; exit ;; # quit
\! ) eval $args ;; # run shell command
* ) _msg "Invalid command: $cmd" ; _menu ;;
esac
done
}
# see if next line no. is a brkpt.
_at_linenumbp() {
if [ -z "${_linebp}" ]; then
return 1
fi
echo "${_curline}" | grep -E "(${_linebp%\|})" >/dev/null 2>&1
return $?
}
# search string brkpts to see if next line in script matches.
_at_stringbp() {
local l;
if [ -z "$_stringbp" ]; then
return 1;
fi
l=${_lines[$_curline-$_firstline+1]}
echo "${l}" | grep -E "\\*(${_stringbp%\|})\\*" >/dev/null 2>&1
return $?
}
# print message to stderr
_msg() {
echo -e "$@" >&2
}
# set brkpt(s) at given line numbers and/or strings
# by appending lines to brkpt file
_setbp() {
declare -i n
case "$1" in
"") _listbp ;;
[0-9]*) #number, set brkpt at that line
n=$1
_linebp="${_linebp}$n|"
_msg "Breakpoint at line " $1
;;
*) #string, set brkpt at next line w/string
_stringbp="${_stringbp}$@|"
_msg "Breakpoint at next line containing $@."
;;
esac
}
# list brkpts and break condition.
_listbp() {
_msg "Breakpoints at lines:"
_msg "${_linebp//\|/ }"
_msg "Breakpoints at strings:"
_msg "${_stringbp//\|/ }"
_msg "Break on condition:"
_msg "$_brcond"
}
# set or clear break condition
_setbc() {
if [ -n "$@" ] ; then
_brcond=$args
_msg "Break when true: $_brcond"
else
_brcond=
_msg "Break condition cleared"
fi
}
# clear all brkpts
_clearbp() {
_linebp=
_stringbp=
_msg "All breakpoints cleared"
}
# toggle execution trace feature
_xtrace() {
let _trace="! $_trace"
_msg "Execution trace \c"
let " $_trace" && _msg "on." || _msg "off."
}
# print command menu
_menu() {
# made commands to be debugger commands by default, no need for '*' prefix
_msg 'bashdb commands:
bp N set breakpoint at line N
bp string set breakpoint at next line containing "string"
bp list breakpoints and break condition
bc string set break condition to "string"
bc clear break condition
cb clear all breakpoints
g start/resume execution
s [N] execute N statements (default 1)
x toggle execution trace on/off (default on)
pr [start|.] [cnt] print "cnt" lines from line no. "start"
?, h, help print this menu
hi show command history
q quit
! cmd [args] execute command "cmd" with "args"
default: last command (in "[ ]" at the prompt)
Readline command line editing (emacs/vi mode) is available'
}
# erase temp files before exiting
_cleanup() {
rm $_dbgfile 2>/dev/null
}
# read $_BUFSIZ lines from $_guineapig into _lines array, starting from line $1
# save number of first line read in _firstline
_readin() {
declare -i _i=1
let _firstline=$1
SEDCMD="$_firstline,$(($_firstline+$_BUFSIZ))p"
sed -n "$SEDCMD" $_guineapig > /tmp/_script.$$
while read -r _lines[$_i]; do
_i=_i+1
done < /tmp/_script.$$
rm -f /tmp/_script.$$ 2>/dev/null
}
_print() {
typeset _start _cnt
if [ -z "$1" ] || [ "$1" = . ]; then
_start=$_curline
else
_start=$1
fi
_cnt=${2:-9}
SEDCMD="$_start,$(($_start+$_cnt))p"
pr -tn $_guineapig | sed -n "$SEDCMD"
}
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