4 perl5db.pl - the perl debugger
8 perl -d your_Perl_script
12 C<perl5db.pl> is the perl debugger. It is loaded automatically by Perl when
13 you invoke a script with C<perl -d>. This documentation tries to outline the
14 structure and services provided by C<perl5db.pl>, and to describe how you
19 The debugger can look pretty forbidding to many Perl programmers. There are
20 a number of reasons for this, many stemming out of the debugger's history.
22 When the debugger was first written, Perl didn't have a lot of its nicer
23 features - no references, no lexical variables, no closures, no object-oriented
24 programming. So a lot of the things one would normally have done using such
25 features was done using global variables, globs and the C<local()> operator
28 Some of these have survived into the current debugger; a few of the more
29 interesting and still-useful idioms are noted in this section, along with notes
30 on the comments themselves.
32 =head2 Why not use more lexicals?
34 Experienced Perl programmers will note that the debugger code tends to use
35 mostly package globals rather than lexically-scoped variables. This is done
36 to allow a significant amount of control of the debugger from outside the
39 Unfortunately, though the variables are accessible, they're not well
40 documented, so it's generally been a decision that hasn't made a lot of
41 difference to most users. Where appropriate, comments have been added to
42 make variables more accessible and usable, with the understanding that these
43 I<are> debugger internals, and are therefore subject to change. Future
44 development should probably attempt to replace the globals with a well-defined
45 API, but for now, the variables are what we've got.
47 =head2 Automated variable stacking via C<local()>
49 As you may recall from reading C<perlfunc>, the C<local()> operator makes a
50 temporary copy of a variable in the current scope. When the scope ends, the
51 old copy is restored. This is often used in the debugger to handle the
52 automatic stacking of variables during recursive calls:
57 # Do some stuff, then ...
61 What happens is that on entry to the subroutine, C<$some_global> is localized,
62 then altered. When the subroutine returns, Perl automatically undoes the
63 localization, restoring the previous value. Voila, automatic stack management.
65 The debugger uses this trick a I<lot>. Of particular note is C<DB::eval>,
66 which lets the debugger get control inside of C<eval>'ed code. The debugger
67 localizes a saved copy of C<$@> inside the subroutine, which allows it to
68 keep C<$@> safe until it C<DB::eval> returns, at which point the previous
69 value of C<$@> is restored. This makes it simple (well, I<simpler>) to keep
70 track of C<$@> inside C<eval>s which C<eval> other C<eval's>.
72 In any case, watch for this pattern. It occurs fairly often.
76 This is used to cleverly reverse the sense of a logical test depending on
77 the value of an auxiliary variable. For instance, the debugger's C<S>
78 (search for subroutines by pattern) allows you to negate the pattern
81 # Find all non-'foo' subs:
84 Boolean algebra states that the truth table for XOR looks like this:
90 (! not present and no match) --> false, don't print
94 (! not present and matches) --> true, print
98 (! present and no match) --> true, print
102 (! present and matches) --> false, don't print
106 As you can see, the first pair applies when C<!> isn't supplied, and
107 the second pair applies when it is. The XOR simply allows us to
108 compact a more complicated if-then-elseif-else into a more elegant
109 (but perhaps overly clever) single test. After all, it needed this
112 =head2 FLAGS, FLAGS, FLAGS
114 There is a certain C programming legacy in the debugger. Some variables,
115 such as C<$single>, C<$trace>, and C<$frame>, have I<magical> values composed
116 of 1, 2, 4, etc. (powers of 2) OR'ed together. This allows several pieces
117 of state to be stored independently in a single scalar.
123 is checking to see if the appropriate bit is on. Since each bit can be
124 "addressed" independently in this way, C<$scalar> is acting sort of like
125 an array of bits. Obviously, since the contents of C<$scalar> are just a
126 bit-pattern, we can save and restore it easily (it will just look like
129 The problem, is of course, that this tends to leave magic numbers scattered
130 all over your program whenever a bit is set, cleared, or checked. So why do
137 First, doing an arithmetical or bitwise operation on a scalar is
138 just about the fastest thing you can do in Perl: C<use constant> actually
139 creates a subroutine call, and array and hash lookups are much slower. Is
140 this over-optimization at the expense of readability? Possibly, but the
141 debugger accesses these variables a I<lot>. Any rewrite of the code will
142 probably have to benchmark alternate implementations and see which is the
143 best balance of readability and speed, and then document how it actually
148 Second, it's very easy to serialize a scalar number. This is done in
149 the restart code; the debugger state variables are saved in C<%ENV> and then
150 restored when the debugger is restarted. Having them be just numbers makes
155 Third, some of these variables are being shared with the Perl core
156 smack in the middle of the interpreter's execution loop. It's much faster for
157 a C program (like the interpreter) to check a bit in a scalar than to access
158 several different variables (or a Perl array).
162 =head2 What are those C<XXX> comments for?
164 Any comment containing C<XXX> means that the comment is either somewhat
165 speculative - it's not exactly clear what a given variable or chunk of
166 code is doing, or that it is incomplete - the basics may be clear, but the
167 subtleties are not completely documented.
169 Send in a patch if you can clear up, fill out, or clarify an C<XXX>.
171 =head1 DATA STRUCTURES MAINTAINED BY CORE
173 There are a number of special data structures provided to the debugger by
174 the Perl interpreter.
176 The array C<@{$main::{'_<'.$filename}}> (aliased locally to C<@dbline>
177 via glob assignment) contains the text from C<$filename>, with each
178 element corresponding to a single line of C<$filename>. Additionally,
179 breakable lines will be dualvars with the numeric component being the
180 memory address of a COP node. Non-breakable lines are dualvar to 0.
182 The hash C<%{'_<'.$filename}> (aliased locally to C<%dbline> via glob
183 assignment) contains breakpoints and actions. The keys are line numbers;
184 you can set individual values, but not the whole hash. The Perl interpreter
185 uses this hash to determine where breakpoints have been set. Any true value is
186 considered to be a breakpoint; C<perl5db.pl> uses C<$break_condition\0$action>.
187 Values are magical in numeric context: 1 if the line is breakable, 0 if not.
189 The scalar C<${"_<$filename"}> simply contains the string C<_<$filename>.
190 This is also the case for evaluated strings that contain subroutines, or
191 which are currently being executed. The $filename for C<eval>ed strings looks
192 like C<(eval 34)> or C<(re_eval 19)>.
194 =head1 DEBUGGER STARTUP
196 When C<perl5db.pl> starts, it reads an rcfile (C<perl5db.ini> for
197 non-interactive sessions, C<.perldb> for interactive ones) that can set a number
198 of options. In addition, this file may define a subroutine C<&afterinit>
199 that will be executed (in the debugger's context) after the debugger has
202 Next, it checks the C<PERLDB_OPTS> environment variable and treats its
203 contents as the argument of a C<o> command in the debugger.
205 =head2 STARTUP-ONLY OPTIONS
207 The following options can only be specified at startup.
208 To set them in your rcfile, add a call to
209 C<&parse_options("optionName=new_value")>.
215 the TTY to use for debugging i/o.
219 if set, goes in NonStop mode. On interrupt, if TTY is not set,
220 uses the value of noTTY or F<$HOME/.perldbtty$$> to find TTY using
221 Term::Rendezvous. Current variant is to have the name of TTY in this
226 if false, a dummy ReadLine is used, so you can debug
227 ReadLine applications.
231 if true, no i/o is performed until interrupt.
235 file or pipe to print line number info to. If it is a
236 pipe, a short "emacs like" message is used.
240 host:port to connect to on remote host for remote debugging.
244 file to store session history to. There is no default and so no
245 history file is written unless this variable is explicitly set.
249 number of commands to store to the file specified in C<HistFile>.
256 &parse_options("NonStop=1 LineInfo=db.out");
257 sub afterinit { $trace = 1; }
259 The script will run without human intervention, putting trace
260 information into C<db.out>. (If you interrupt it, you had better
261 reset C<LineInfo> to something I<interactive>!)
263 =head1 INTERNALS DESCRIPTION
265 =head2 DEBUGGER INTERFACE VARIABLES
267 Perl supplies the values for C<%sub>. It effectively inserts
268 a C<&DB::DB();> in front of each place that can have a
269 breakpoint. At each subroutine call, it calls C<&DB::sub> with
270 C<$DB::sub> set to the called subroutine. It also inserts a C<BEGIN
271 {require 'perl5db.pl'}> before the first line.
273 After each C<require>d file is compiled, but before it is executed, a
274 call to C<&DB::postponed($main::{'_<'.$filename})> is done. C<$filename>
275 is the expanded name of the C<require>d file (as found via C<%INC>).
277 =head3 IMPORTANT INTERNAL VARIABLES
281 Used to control when the debugger will attempt to acquire another TTY to be
286 =item * 1 - on C<fork()>
288 =item * 2 - debugger is started inside debugger
290 =item * 4 - on startup
296 The value -2 indicates that no return value should be printed.
297 Any other positive value causes C<DB::sub> to print return values.
301 The item to be eval'ed by C<DB::eval>. Used to prevent messing with the current
302 contents of C<@_> when C<DB::eval> is called.
306 Determines what messages (if any) will get printed when a subroutine (or eval)
307 is entered or exited.
311 =item * 0 - No enter/exit messages
313 =item * 1 - Print I<entering> messages on subroutine entry
315 =item * 2 - Adds exit messages on subroutine exit. If no other flag is on, acts like 1+2.
317 =item * 4 - Extended messages: C<< <in|out> I<context>=I<fully-qualified sub name> from I<file>:I<line> >>. If no other flag is on, acts like 1+4.
319 =item * 8 - Adds parameter information to messages, and overloaded stringify and tied FETCH is enabled on the printed arguments. Ignored if C<4> is not on.
321 =item * 16 - Adds C<I<context> return from I<subname>: I<value>> messages on subroutine/eval exit. Ignored if C<4> is is not on.
325 To get everything, use C<$frame=30> (or C<o f=30> as a debugger command).
326 The debugger internally juggles the value of C<$frame> during execution to
327 protect external modules that the debugger uses from getting traced.
331 Tracks current debugger nesting level. Used to figure out how many
332 C<E<lt>E<gt>> pairs to surround the line number with when the debugger
333 outputs a prompt. Also used to help determine if the program has finished
334 during command parsing.
336 =head4 C<$onetimeDump>
338 Controls what (if anything) C<DB::eval()> will print after evaluating an
343 =item * C<undef> - don't print anything
345 =item * C<dump> - use C<dumpvar.pl> to display the value returned
347 =item * C<methods> - print the methods callable on the first item returned
351 =head4 C<$onetimeDumpDepth>
353 Controls how far down C<dumpvar.pl> will go before printing C<...> while
354 dumping a structure. Numeric. If C<undef>, print all levels.
358 Used to track whether or not an C<INT> signal has been detected. C<DB::DB()>,
359 which is called before every statement, checks this and puts the user into
360 command mode if it finds C<$signal> set to a true value.
364 Controls behavior during single-stepping. Stacked in C<@stack> on entry to
365 each subroutine; popped again at the end of each subroutine.
369 =item * 0 - run continuously.
371 =item * 1 - single-step, go into subs. The C<s> command.
373 =item * 2 - single-step, don't go into subs. The C<n> command.
375 =item * 4 - print current sub depth (turned on to force this when C<too much
382 Controls the output of trace information.
386 =item * 1 - The C<t> command was entered to turn on tracing (every line executed is printed)
388 =item * 2 - watch expressions are active
390 =item * 4 - user defined a C<watchfunction()> in C<afterinit()>
394 =head4 C<$slave_editor>
396 1 if C<LINEINFO> was directed to a pipe; 0 otherwise.
400 Stack of filehandles that C<DB::readline()> will read commands from.
401 Manipulated by the debugger's C<source> command and C<DB::readline()> itself.
405 Local alias to the magical line array, C<@{$main::{'_<'.$filename}}> ,
406 supplied by the Perl interpreter to the debugger. Contains the source.
410 Previous values of watch expressions. First set when the expression is
411 entered; reset whenever the watch expression changes.
415 Saves important globals (C<$@>, C<$!>, C<$^E>, C<$,>, C<$/>, C<$\>, C<$^W>)
416 so that the debugger can substitute safe values while it's running, and
417 restore them when it returns control.
421 Saves the current value of C<$single> on entry to a subroutine.
422 Manipulated by the C<c> command to turn off tracing in all subs above the
427 The 'watch' expressions: to be evaluated before each line is executed.
431 The typeahead buffer, used by C<DB::readline>.
435 Command aliases. Stored as character strings to be substituted for a command
438 =head4 C<%break_on_load>
440 Keys are file names, values are 1 (break when this file is loaded) or undef
441 (don't break when it is loaded).
445 Keys are line numbers, values are C<condition\0action>. If used in numeric
446 context, values are 0 if not breakable, 1 if breakable, no matter what is
447 in the actual hash entry.
449 =head4 C<%had_breakpoints>
451 Keys are file names; values are bitfields:
455 =item * 1 - file has a breakpoint in it.
457 =item * 2 - file has an action in it.
461 A zero or undefined value means this file has neither.
465 Stores the debugger options. These are character string values.
469 Saves breakpoints for code that hasn't been compiled yet.
470 Keys are subroutine names, values are:
474 =item * C<compile> - break when this sub is compiled
476 =item * C<< break +0 if <condition> >> - break (conditionally) at the start of this routine. The condition will be '1' if no condition was specified.
480 =head4 C<%postponed_file>
482 This hash keeps track of breakpoints that need to be set for files that have
483 not yet been compiled. Keys are filenames; values are references to hashes.
484 Each of these hashes is keyed by line number, and its values are breakpoint
485 definitions (C<condition\0action>).
487 =head1 DEBUGGER INITIALIZATION
489 The debugger's initialization actually jumps all over the place inside this
490 package. This is because there are several BEGIN blocks (which of course
491 execute immediately) spread through the code. Why is that?
493 The debugger needs to be able to change some things and set some things up
494 before the debugger code is compiled; most notably, the C<$deep> variable that
495 C<DB::sub> uses to tell when a program has recursed deeply. In addition, the
496 debugger has to turn off warnings while the debugger code is compiled, but then
497 restore them to their original setting before the program being debugged begins
500 The first C<BEGIN> block simply turns off warnings by saving the current
501 setting of C<$^W> and then setting it to zero. The second one initializes
502 the debugger variables that are needed before the debugger begins executing.
503 The third one puts C<$^X> back to its former value.
505 We'll detail the second C<BEGIN> block later; just remember that if you need
506 to initialize something before the debugger starts really executing, that's
513 BEGIN {eval 'use IO::Handle'}; # Needed for flush only? breaks under miniperl
517 $^V =~ /^v(\d+\.\d+)/;
518 feature->import(":$1");
521 # Debugger for Perl 5.00x; perl5db.pl patch level:
524 $header = "perl5db.pl version $VERSION";
526 =head1 DEBUGGER ROUTINES
530 This function replaces straight C<eval()> inside the debugger; it simplifies
531 the process of evaluating code in the user's context.
533 The code to be evaluated is passed via the package global variable
534 C<$DB::evalarg>; this is done to avoid fiddling with the contents of C<@_>.
536 Before we do the C<eval()>, we preserve the current settings of C<$trace>,
537 C<$single>, C<$^D> and C<$usercontext>. The latter contains the
538 preserved values of C<$@>, C<$!>, C<$^E>, C<$,>, C<$/>, C<$\>, C<$^W> and the
539 user's current package, grabbed when C<DB::DB> got control. This causes the
540 proper context to be used when the eval is actually done. Afterward, we
541 restore C<$trace>, C<$single>, and C<$^D>.
543 Next we need to handle C<$@> without getting confused. We save C<$@> in a
544 local lexical, localize C<$saved[0]> (which is where C<save()> will put
545 C<$@>), and then call C<save()> to capture C<$@>, C<$!>, C<$^E>, C<$,>,
546 C<$/>, C<$\>, and C<$^W>) and set C<$,>, C<$/>, C<$\>, and C<$^W> to values
547 considered sane by the debugger. If there was an C<eval()> error, we print
548 it on the debugger's output. If C<$onetimedump> is defined, we call
549 C<dumpit> if it's set to 'dump', or C<methods> if it's set to
550 'methods'. Setting it to something else causes the debugger to do the eval
551 but not print the result - handy if you want to do something else with it
552 (the "watch expressions" code does this to get the value of the watch
553 expression but not show it unless it matters).
555 In any case, we then return the list of output from C<eval> to the caller,
556 and unwinding restores the former version of C<$@> in C<@saved> as well
557 (the localization of C<$saved[0]> goes away at the end of this scope).
559 =head3 Parameters and variables influencing execution of DB::eval()
561 C<DB::eval> isn't parameterized in the standard way; this is to keep the
562 debugger's calls to C<DB::eval()> from mucking with C<@_>, among other things.
563 The variables listed below influence C<DB::eval()>'s execution directly.
567 =item C<$evalarg> - the thing to actually be eval'ed
569 =item C<$trace> - Current state of execution tracing
571 =item C<$single> - Current state of single-stepping
573 =item C<$onetimeDump> - what is to be displayed after the evaluation
575 =item C<$onetimeDumpDepth> - how deep C<dumpit()> should go when dumping results
579 The following variables are altered by C<DB::eval()> during its execution. They
580 are "stacked" via C<local()>, enabling recursive calls to C<DB::eval()>.
584 =item C<@res> - used to capture output from actual C<eval>.
586 =item C<$otrace> - saved value of C<$trace>.
588 =item C<$osingle> - saved value of C<$single>.
590 =item C<$od> - saved value of C<$^D>.
592 =item C<$saved[0]> - saved value of C<$@>.
594 =item $\ - for output of C<$@> if there is an evaluation error.
598 =head3 The problem of lexicals
600 The context of C<DB::eval()> presents us with some problems. Obviously,
601 we want to be 'sandboxed' away from the debugger's internals when we do
602 the eval, but we need some way to control how punctuation variables and
603 debugger globals are used.
605 We can't use local, because the code inside C<DB::eval> can see localized
606 variables; and we can't use C<my> either for the same reason. The code
607 in this routine compromises and uses C<my>.
609 After this routine is over, we don't have user code executing in the debugger's
610 context, so we can use C<my> freely.
614 ############################################## Begin lexical danger zone
616 # 'my' variables used here could leak into (that is, be visible in)
617 # the context that the code being evaluated is executing in. This means that
618 # the code could modify the debugger's variables.
620 # Fiddling with the debugger's context could be Bad. We insulate things as
625 # 'my' would make it visible from user code
626 # but so does local! --tchrist
627 # Remember: this localizes @DB::res, not @main::res.
631 # Try to keep the user code from messing with us. Save these so that
632 # even if the eval'ed code changes them, we can put them back again.
633 # Needed because the user could refer directly to the debugger's
634 # package globals (and any 'my' variables in this containing scope)
635 # inside the eval(), and we want to try to stay safe.
636 local $otrace = $trace;
637 local $osingle = $single;
640 # Untaint the incoming eval() argument.
641 { ($evalarg) = $evalarg =~ /(.*)/s; }
643 # $usercontext built in DB::DB near the comment
644 # "set up the context for DB::eval ..."
645 # Evaluate and save any results.
646 @res = eval "$usercontext $evalarg;\n"; # '\n' for nice recursive debug
648 # Restore those old values.
654 # Save the current value of $@, and preserve it in the debugger's copy
655 # of the saved precious globals.
658 # Since we're only saving $@, we only have to localize the array element
659 # that it will be stored in.
660 local $saved[0]; # Preserve the old value of $@
663 # Now see whether we need to report an error back to the user.
669 # Display as required by the caller. $onetimeDump and $onetimedumpDepth
670 # are package globals.
671 elsif ($onetimeDump) {
672 if ( $onetimeDump eq 'dump' ) {
673 local $option{dumpDepth} = $onetimedumpDepth
674 if defined $onetimedumpDepth;
675 dumpit( $OUT, \@res );
677 elsif ( $onetimeDump eq 'methods' ) {
680 } ## end elsif ($onetimeDump)
684 ############################################## End lexical danger zone
686 # After this point it is safe to introduce lexicals.
687 # The code being debugged will be executing in its own context, and
688 # can't see the inside of the debugger.
690 # However, one should not overdo it: leave as much control from outside as
691 # possible. If you make something a lexical, it's not going to be addressable
692 # from outside the debugger even if you know its name.
694 # This file is automatically included if you do perl -d.
695 # It's probably not useful to include this yourself.
697 # Before venturing further into these twisty passages, it is
698 # wise to read the perldebguts man page or risk the ire of dragons.
700 # (It should be noted that perldebguts will tell you a lot about
701 # the underlying mechanics of how the debugger interfaces into the
702 # Perl interpreter, but not a lot about the debugger itself. The new
703 # comments in this code try to address this problem.)
705 # Note that no subroutine call is possible until &DB::sub is defined
706 # (for subroutines defined outside of the package DB). In fact the same is
707 # true if $deep is not defined.
709 # Enhanced by ilya@math.ohio-state.edu (Ilya Zakharevich)
711 # modified Perl debugger, to be run from Emacs in perldb-mode
712 # Ray Lischner (uunet!mntgfx!lisch) as of 5 Nov 1990
713 # Johan Vromans -- upgrade to 4.0 pl 10
714 # Ilya Zakharevich -- patches after 5.001 (and some before ;-)
716 # (We have made efforts to clarify the comments in the change log
717 # in other places; some of them may seem somewhat obscure as they
718 # were originally written, and explaining them away from the code
719 # in question seems conterproductive.. -JM)
721 ########################################################################
723 # + A lot of things changed after 0.94. First of all, core now informs
724 # debugger about entry into XSUBs, overloaded operators, tied operations,
725 # BEGIN and END. Handy with 'O f=2'.
726 # + This can make debugger a little bit too verbose, please be patient
727 # and report your problems promptly.
728 # + Now the option frame has 3 values: 0,1,2. XXX Document!
729 # + Note that if DESTROY returns a reference to the object (or object),
730 # the deletion of data may be postponed until the next function call,
731 # due to the need to examine the return value.
734 # + 'v' command shows versions.
737 # + 'v' command shows version of readline.
738 # primitive completion works (dynamic variables, subs for 'b' and 'l',
739 # options). Can 'p %var'
740 # + Better help ('h <' now works). New commands <<, >>, {, {{.
741 # {dump|print}_trace() coded (to be able to do it from <<cmd).
742 # + 'c sub' documented.
743 # + At last enough magic combined to stop after the end of debuggee.
744 # + !! should work now (thanks to Emacs bracket matching an extra
745 # ']' in a regexp is caught).
746 # + 'L', 'D' and 'A' span files now (as documented).
747 # + Breakpoints in 'require'd code are possible (used in 'R').
748 # + Some additional words on internal work of debugger.
749 # + 'b load filename' implemented.
750 # + 'b postpone subr' implemented.
751 # + now only 'q' exits debugger (overwritable on $inhibit_exit).
752 # + When restarting debugger breakpoints/actions persist.
753 # + Buglet: When restarting debugger only one breakpoint/action per
754 # autoloaded function persists.
756 # Changes: 0.97: NonStop will not stop in at_exit().
757 # + Option AutoTrace implemented.
758 # + Trace printed differently if frames are printed too.
759 # + new 'inhibitExit' option.
760 # + printing of a very long statement interruptible.
761 # Changes: 0.98: New command 'm' for printing possible methods
762 # + 'l -' is a synonym for '-'.
763 # + Cosmetic bugs in printing stack trace.
764 # + 'frame' & 8 to print "expanded args" in stack trace.
765 # + Can list/break in imported subs.
766 # + new 'maxTraceLen' option.
767 # + frame & 4 and frame & 8 granted.
769 # + nonstoppable lines do not have ':' near the line number.
770 # + 'b compile subname' implemented.
771 # + Will not use $` any more.
772 # + '-' behaves sane now.
773 # Changes: 0.99: Completion for 'f', 'm'.
774 # + 'm' will remove duplicate names instead of duplicate functions.
775 # + 'b load' strips trailing whitespace.
776 # completion ignores leading '|'; takes into account current package
777 # when completing a subroutine name (same for 'l').
778 # Changes: 1.07: Many fixed by tchrist 13-March-2000
780 # + Added bare minimal security checks on perldb rc files, plus
781 # comments on what else is needed.
782 # + Fixed the ornaments that made "|h" completely unusable.
783 # They are not used in print_help if they will hurt. Strip pod
784 # if we're paging to less.
785 # + Fixed mis-formatting of help messages caused by ornaments
786 # to restore Larry's original formatting.
787 # + Fixed many other formatting errors. The code is still suboptimal,
788 # and needs a lot of work at restructuring. It's also misindented
790 # + Fixed bug where trying to look at an option like your pager
792 # + Fixed some $? processing. Note: if you use csh or tcsh, you will
793 # lose. You should consider shell escapes not using their shell,
794 # or else not caring about detailed status. This should really be
795 # unified into one place, too.
796 # + Fixed bug where invisible trailing whitespace on commands hoses you,
797 # tricking Perl into thinking you weren't calling a debugger command!
798 # + Fixed bug where leading whitespace on commands hoses you. (One
799 # suggests a leading semicolon or any other irrelevant non-whitespace
800 # to indicate literal Perl code.)
801 # + Fixed bugs that ate warnings due to wrong selected handle.
802 # + Fixed a precedence bug on signal stuff.
803 # + Fixed some unseemly wording.
804 # + Fixed bug in help command trying to call perl method code.
805 # + Fixed to call dumpvar from exception handler. SIGPIPE killed us.
807 # + Added some comments. This code is still nasty spaghetti.
808 # + Added message if you clear your pre/post command stacks which was
809 # very easy to do if you just typed a bare >, <, or {. (A command
810 # without an argument should *never* be a destructive action; this
811 # API is fundamentally screwed up; likewise option setting, which
812 # is equally buggered.)
813 # + Added command stack dump on argument of "?" for >, <, or {.
814 # + Added a semi-built-in doc viewer command that calls man with the
815 # proper %Config::Config path (and thus gets caching, man -k, etc),
816 # or else perldoc on obstreperous platforms.
817 # + Added to and rearranged the help information.
818 # + Detected apparent misuse of { ... } to declare a block; this used
819 # to work but now is a command, and mysteriously gave no complaint.
821 # Changes: 1.08: Apr 25, 2001 Jon Eveland <jweveland@yahoo.com>
823 # + This patch to perl5db.pl cleans up formatting issues on the help
824 # summary (h h) screen in the debugger. Mostly columnar alignment
825 # issues, plus converted the printed text to use all spaces, since
826 # tabs don't seem to help much here.
828 # Changes: 1.09: May 19, 2001 Ilya Zakharevich <ilya@math.ohio-state.edu>
829 # Minor bugs corrected;
830 # + Support for auto-creation of new TTY window on startup, either
831 # unconditionally, or if started as a kid of another debugger session;
832 # + New 'O'ption CreateTTY
833 # I<CreateTTY> bits control attempts to create a new TTY on events:
835 # 2: debugger is started inside debugger
837 # + Code to auto-create a new TTY window on OS/2 (currently one
838 # extra window per session - need named pipes to have more...);
839 # + Simplified interface for custom createTTY functions (with a backward
840 # compatibility hack); now returns the TTY name to use; return of ''
841 # means that the function reset the I/O handles itself;
842 # + Better message on the semantic of custom createTTY function;
843 # + Convert the existing code to create a TTY into a custom createTTY
845 # + Consistent support for TTY names of the form "TTYin,TTYout";
846 # + Switch line-tracing output too to the created TTY window;
847 # + make 'b fork' DWIM with CORE::GLOBAL::fork;
848 # + High-level debugger API cmd_*():
849 # cmd_b_load($filenamepart) # b load filenamepart
850 # cmd_b_line($lineno [, $cond]) # b lineno [cond]
851 # cmd_b_sub($sub [, $cond]) # b sub [cond]
852 # cmd_stop() # Control-C
853 # cmd_d($lineno) # d lineno (B)
854 # The cmd_*() API returns FALSE on failure; in this case it outputs
855 # the error message to the debugging output.
856 # + Low-level debugger API
857 # break_on_load($filename) # b load filename
858 # @files = report_break_on_load() # List files with load-breakpoints
859 # breakable_line_in_filename($name, $from [, $to])
860 # # First breakable line in the
861 # # range $from .. $to. $to defaults
862 # # to $from, and may be less than
864 # breakable_line($from [, $to]) # Same for the current file
865 # break_on_filename_line($name, $lineno [, $cond])
866 # # Set breakpoint,$cond defaults to
868 # break_on_filename_line_range($name, $from, $to [, $cond])
869 # # As above, on the first
870 # # breakable line in range
871 # break_on_line($lineno [, $cond]) # As above, in the current file
872 # break_subroutine($sub [, $cond]) # break on the first breakable line
873 # ($name, $from, $to) = subroutine_filename_lines($sub)
874 # # The range of lines of the text
875 # The low-level API returns TRUE on success, and die()s on failure.
877 # Changes: 1.10: May 23, 2001 Daniel Lewart <d-lewart@uiuc.edu>
879 # + Fixed warnings generated by "perl -dWe 42"
880 # + Corrected spelling errors
881 # + Squeezed Help (h) output into 80 columns
883 # Changes: 1.11: May 24, 2001 David Dyck <dcd@tc.fluke.com>
884 # + Made "x @INC" work like it used to
886 # Changes: 1.12: May 24, 2001 Daniel Lewart <d-lewart@uiuc.edu>
887 # + Fixed warnings generated by "O" (Show debugger options)
888 # + Fixed warnings generated by "p 42" (Print expression)
889 # Changes: 1.13: Jun 19, 2001 Scott.L.Miller@compaq.com
890 # + Added windowSize option
891 # Changes: 1.14: Oct 9, 2001 multiple
892 # + Clean up after itself on VMS (Charles Lane in 12385)
893 # + Adding "@ file" syntax (Peter Scott in 12014)
894 # + Debug reloading selfloaded stuff (Ilya Zakharevich in 11457)
895 # + $^S and other debugger fixes (Ilya Zakharevich in 11120)
896 # + Forgot a my() declaration (Ilya Zakharevich in 11085)
897 # Changes: 1.15: Nov 6, 2001 Michael G Schwern <schwern@pobox.com>
898 # + Updated 1.14 change log
899 # + Added *dbline explanatory comments
900 # + Mentioning perldebguts man page
901 # Changes: 1.16: Feb 15, 2002 Mark-Jason Dominus <mjd@plover.com>
902 # + $onetimeDump improvements
903 # Changes: 1.17: Feb 20, 2002 Richard Foley <richard.foley@rfi.net>
904 # Moved some code to cmd_[.]()'s for clarity and ease of handling,
905 # rationalised the following commands and added cmd_wrapper() to
906 # enable switching between old and frighteningly consistent new
907 # behaviours for diehards: 'o CommandSet=pre580' (sigh...)
908 # a(add), A(del) # action expr (added del by line)
909 # + b(add), B(del) # break [line] (was b,D)
910 # + w(add), W(del) # watch expr (was W,W)
911 # # added del by expr
912 # + h(summary), h h(long) # help (hh) (was h h,h)
913 # + m(methods), M(modules) # ... (was m,v)
914 # + o(option) # lc (was O)
915 # + v(view code), V(view Variables) # ... (was w,V)
916 # Changes: 1.18: Mar 17, 2002 Richard Foley <richard.foley@rfi.net>
917 # + fixed missing cmd_O bug
918 # Changes: 1.19: Mar 29, 2002 Spider Boardman
919 # + Added missing local()s -- DB::DB is called recursively.
920 # Changes: 1.20: Feb 17, 2003 Richard Foley <richard.foley@rfi.net>
921 # + pre'n'post commands no longer trashed with no args
922 # + watch val joined out of eval()
923 # Changes: 1.21: Jun 04, 2003 Joe McMahon <mcmahon@ibiblio.org>
924 # + Added comments and reformatted source. No bug fixes/enhancements.
925 # + Includes cleanup by Robin Barker and Jarkko Hietaniemi.
926 # Changes: 1.22 Jun 09, 2003 Alex Vandiver <alexmv@MIT.EDU>
927 # + Flush stdout/stderr before the debugger prompt is printed.
928 # Changes: 1.23: Dec 21, 2003 Dominique Quatravaux
929 # + Fix a side-effect of bug #24674 in the perl debugger ("odd taint bug")
930 # Changes: 1.24: Mar 03, 2004 Richard Foley <richard.foley@rfi.net>
931 # + Added command to save all debugger commands for sourcing later.
932 # + Added command to display parent inheritance tree of given class.
933 # + Fixed minor newline in history bug.
934 # Changes: 1.25: Apr 17, 2004 Richard Foley <richard.foley@rfi.net>
935 # + Fixed option bug (setting invalid options + not recognising valid short forms)
936 # Changes: 1.26: Apr 22, 2004 Richard Foley <richard.foley@rfi.net>
937 # + unfork the 5.8.x and 5.9.x debuggers.
938 # + whitespace and assertions call cleanup across versions
939 # + H * deletes (resets) history
940 # + i now handles Class + blessed objects
941 # Changes: 1.27: May 09, 2004 Richard Foley <richard.foley@rfi.net>
942 # + updated pod page references - clunky.
943 # + removed windowid restriction for forking into an xterm.
944 # + more whitespace again.
945 # + wrapped restart and enabled rerun [-n] (go back n steps) command.
946 # Changes: 1.28: Oct 12, 2004 Richard Foley <richard.foley@rfi.net>
947 # + Added threads support (inc. e and E commands)
948 # Changes: 1.29: Nov 28, 2006 Bo Lindbergh <blgl@hagernas.com>
949 # + Added macosx_get_fork_TTY support
950 # Changes: 1.30: Mar 06, 2007 Andreas Koenig <andk@cpan.org>
951 # + Added HistFile, HistSize
953 # + Remove support for assertions and -A
954 # + stop NEXT::AUTOLOAD from emitting warnings under the debugger. RT #25053
955 # + "update for Mac OS X 10.5" [finding the tty device]
956 # + "What I needed to get the forked debugger to work" [on VMS]
957 # + [perl #57016] debugger: o warn=0 die=0 ignored
958 # + Note, but don't use, PERLDBf_SAVESRC
959 # + Fix #7013: lvalue subs not working inside debugger
960 # Changes: 1.32: Jun 03, 2009 Jonathan Leto <jonathan@leto.net>
961 # + Fix bug where a key _< with undefined value was put into the symbol table
962 # + when the $filename variable is not set
964 # + Debugger prints lines to the remote port when it forks and openes a new port (f633fd2)
965 # + The debugger now continues to use RemotePort when it's been configured to use it. (11653f7)
966 # + Stop using $ENV{LESS} for parameters not intended for less (d463cf2)
967 # + Configure has a path to less and perl5db.pl can use it (bf320d6)
968 # + Die with $@ instead of empty message (86755f4)
969 # + Remove extra/useless $@ check after eval { require PadWalker } (which is still checked) (dab8d6d)
970 # + Promote eval( "require ..." ) to eval { require ... } (4a49187)
971 # + Promote eval { require( ... )} || die to mere require( ... ) (999f23b)
972 # + Remove indirect object notation from debugger (bee4b46)
973 # + Document that @{$main::{'_<'.$filename}} lines are dualvar to (COP*). (7e17a74)
974 # + Remove MacOS classic support from the debugger. (2b894b7)
975 ########################################################################
977 =head1 DEBUGGER INITIALIZATION
979 The debugger starts up in phases.
983 First, it initializes the environment it wants to run in: turning off
984 warnings during its own compilation, defining variables which it will need
985 to avoid warnings later, setting itself up to not exit when the program
986 terminates, and defaulting to printing return values for the C<r> command.
990 # Needed for the statement after exec():
992 # This BEGIN block is simply used to switch off warnings during debugger
993 # compilation. Probably it would be better practice to fix the warnings,
994 # but this is how it's done at the moment.
999 } # Switch compilation warnings off until another BEGIN.
1001 local ($^W) = 0; # Switch run-time warnings off during init.
1003 =head2 THREADS SUPPORT
1005 If we are running under a threaded Perl, we require threads and threads::shared
1006 if the environment variable C<PERL5DB_THREADED> is set, to enable proper
1007 threaded debugger control. C<-dt> can also be used to set this.
1009 Each new thread will be announced and the debugger prompt will always inform
1010 you of each new thread created. It will also indicate the thread id in which
1011 we are currently running within the prompt like this:
1015 Where C<[tid]> is an integer thread id and C<$i> is the familiar debugger
1016 command prompt. The prompt will show: C<[0]> when running under threads, but
1017 not actually in a thread. C<[tid]> is consistent with C<gdb> usage.
1019 While running under threads, when you set or delete a breakpoint (etc.), this
1020 will apply to all threads, not just the currently running one. When you are
1021 in a currently executing thread, you will stay there until it completes. With
1022 the current implementation it is not currently possible to hop from one thread
1025 The C<e> and C<E> commands are currently fairly minimal - see C<h e> and C<h E>.
1027 Note that threading support was built into the debugger as of Perl version
1028 C<5.8.6> and debugger version C<1.2.8>.
1033 # ensure we can share our non-threaded variables or no-op
1034 if ($ENV{PERL5DB_THREADED}) {
1036 require threads::shared;
1037 import threads::shared qw(share);
1041 print "Threads support enabled\n";
1048 # This would probably be better done with "use vars", but that wasn't around
1049 # when this code was originally written. (Neither was "use strict".) And on
1050 # the principle of not fiddling with something that was working, this was
1053 # These variables control the execution of 'dumpvar.pl'.
1054 $dumpvar::hashDepth,
1055 $dumpvar::arrayDepth,
1056 $dumpvar::dumpDBFiles,
1057 $dumpvar::dumpPackages,
1058 $dumpvar::quoteHighBit,
1059 $dumpvar::printUndef,
1060 $dumpvar::globPrint,
1061 $dumpvar::usageOnly,
1063 # used to save @ARGV and extract any debugger-related flags.
1066 # used to control die() reporting in diesignal()
1069 # used to prevent multiple entries to diesignal()
1070 # (if for instance diesignal() itself dies)
1073 # used to prevent the debugger from running nonstop
1079 # without threads, $filename is not defined until DB::DB is called
1080 foreach my $k (keys (%INC)) {
1081 &share(\$main::{'_<'.$filename}) if defined $filename;
1084 # Command-line + PERLLIB:
1085 # Save the contents of @INC before they are modified elsewhere.
1088 # This was an attempt to clear out the previous values of various
1089 # trapped errors. Apparently it didn't help. XXX More info needed!
1090 # $prevwarn = $prevdie = $prevbus = $prevsegv = ''; # Does not help?!
1092 # We set these variables to safe values. We don't want to blindly turn
1093 # off warnings, because other packages may still want them.
1094 $trace = $signal = $single = 0; # Uninitialized warning suppression
1095 # (local $^W cannot help - other packages!).
1097 # Default to not exiting when program finishes; print the return
1098 # value when the 'r' command is used to return from a subroutine.
1099 $inhibit_exit = $option{PrintRet} = 1;
1101 # Default to 1 so the prompt will display the first line.
1102 $trace_to_depth = 1;
1104 =head1 OPTION PROCESSING
1106 The debugger's options are actually spread out over the debugger itself and
1107 C<dumpvar.pl>; some of these are variables to be set, while others are
1108 subs to be called with a value. To try to make this a little easier to
1109 manage, the debugger uses a few data structures to define what options
1110 are legal and how they are to be processed.
1112 First, the C<@options> array defines the I<names> of all the options that
1118 CommandSet HistFile HistSize
1119 hashDepth arrayDepth dumpDepth
1120 DumpDBFiles DumpPackages DumpReused
1121 compactDump veryCompact quote
1122 HighBit undefPrint globPrint
1123 PrintRet UsageOnly frame
1125 ReadLine NonStop LineInfo
1126 maxTraceLen recallCommand ShellBang
1127 pager tkRunning ornaments
1128 signalLevel warnLevel dieLevel
1129 inhibit_exit ImmediateStop bareStringify
1130 CreateTTY RemotePort windowSize
1134 @RememberOnROptions = qw(DollarCaretP);
1138 Second, C<optionVars> lists the variables that each option uses to save its
1144 hashDepth => \$dumpvar::hashDepth,
1145 arrayDepth => \$dumpvar::arrayDepth,
1146 CommandSet => \$CommandSet,
1147 DumpDBFiles => \$dumpvar::dumpDBFiles,
1148 DumpPackages => \$dumpvar::dumpPackages,
1149 DumpReused => \$dumpvar::dumpReused,
1150 HighBit => \$dumpvar::quoteHighBit,
1151 undefPrint => \$dumpvar::printUndef,
1152 globPrint => \$dumpvar::globPrint,
1153 UsageOnly => \$dumpvar::usageOnly,
1154 CreateTTY => \$CreateTTY,
1155 bareStringify => \$dumpvar::bareStringify,
1157 AutoTrace => \$trace,
1158 inhibit_exit => \$inhibit_exit,
1159 maxTraceLen => \$maxtrace,
1160 ImmediateStop => \$ImmediateStop,
1161 RemotePort => \$remoteport,
1162 windowSize => \$window,
1163 HistFile => \$histfile,
1164 HistSize => \$histsize,
1169 Third, C<%optionAction> defines the subroutine to be called to process each
1175 compactDump => \&dumpvar::compactDump,
1176 veryCompact => \&dumpvar::veryCompact,
1177 quote => \&dumpvar::quote,
1180 ReadLine => \&ReadLine,
1181 NonStop => \&NonStop,
1182 LineInfo => \&LineInfo,
1183 recallCommand => \&recallCommand,
1184 ShellBang => \&shellBang,
1186 signalLevel => \&signalLevel,
1187 warnLevel => \&warnLevel,
1188 dieLevel => \&dieLevel,
1189 tkRunning => \&tkRunning,
1190 ornaments => \&ornaments,
1191 RemotePort => \&RemotePort,
1192 DollarCaretP => \&DollarCaretP,
1197 Last, the C<%optionRequire> notes modules that must be C<require>d if an
1202 # Note that this list is not complete: several options not listed here
1203 # actually require that dumpvar.pl be loaded for them to work, but are
1204 # not in the table. A subsequent patch will correct this problem; for
1205 # the moment, we're just recommenting, and we are NOT going to change
1208 compactDump => 'dumpvar.pl',
1209 veryCompact => 'dumpvar.pl',
1210 quote => 'dumpvar.pl',
1215 There are a number of initialization-related variables which can be set
1216 by putting code to set them in a BEGIN block in the C<PERL5DB> environment
1217 variable. These are:
1221 =item C<$rl> - readline control XXX needs more explanation
1223 =item C<$warnLevel> - whether or not debugger takes over warning handling
1225 =item C<$dieLevel> - whether or not debugger takes over die handling
1227 =item C<$signalLevel> - whether or not debugger takes over signal handling
1229 =item C<$pre> - preprompt actions (array reference)
1231 =item C<$post> - postprompt actions (array reference)
1235 =item C<$CreateTTY> - whether or not to create a new TTY for this debugger
1237 =item C<$CommandSet> - which command set to use (defaults to new, documented set)
1243 # These guys may be defined in $ENV{PERL5DB} :
1244 $rl = 1 unless defined $rl;
1245 $warnLevel = 1 unless defined $warnLevel;
1246 $dieLevel = 1 unless defined $dieLevel;
1247 $signalLevel = 1 unless defined $signalLevel;
1248 $pre = [] unless defined $pre;
1249 $post = [] unless defined $post;
1250 $pretype = [] unless defined $pretype;
1251 $CreateTTY = 3 unless defined $CreateTTY;
1252 $CommandSet = '580' unless defined $CommandSet;
1257 share($signalLevel);
1267 The default C<die>, C<warn>, and C<signal> handlers are set up.
1271 warnLevel($warnLevel);
1272 dieLevel($dieLevel);
1273 signalLevel($signalLevel);
1277 The pager to be used is needed next. We try to get it from the
1278 environment first. If it's not defined there, we try to find it in
1279 the Perl C<Config.pm>. If it's not there, we default to C<more>. We
1280 then call the C<pager()> function to save the pager name.
1284 # This routine makes sure $pager is set up so that '|' can use it.
1287 # If PAGER is defined in the environment, use it.
1291 # If not, see if Config.pm defines it.
1292 : eval { require Config }
1293 && defined $Config::Config{pager}
1294 ? $Config::Config{pager}
1296 # If not, fall back to 'more'.
1299 unless defined $pager;
1303 We set up the command to be used to access the man pages, the command
1304 recall character (C<!> unless otherwise defined) and the shell escape
1305 character (C<!> unless otherwise defined). Yes, these do conflict, and
1306 neither works in the debugger at the moment.
1312 # Set up defaults for command recall and shell escape (note:
1313 # these currently don't work in linemode debugging).
1314 &recallCommand("!") unless defined $prc;
1315 &shellBang("!") unless defined $psh;
1319 We then set up the gigantic string containing the debugger help.
1320 We also set the limit on the number of arguments we'll display during a
1327 # If we didn't get a default for the length of eval/stack trace args,
1329 $maxtrace = 400 unless defined $maxtrace;
1331 =head2 SETTING UP THE DEBUGGER GREETING
1333 The debugger I<greeting> helps to inform the user how many debuggers are
1334 running, and whether the current debugger is the primary or a child.
1336 If we are the primary, we just hang onto our pid so we'll have it when
1337 or if we start a child debugger. If we are a child, we'll set things up
1338 so we'll have a unique greeting and so the parent will give us our own
1341 We save the current contents of the C<PERLDB_PIDS> environment variable
1342 because we mess around with it. We'll also need to hang onto it because
1343 we'll need it if we restart.
1345 Child debuggers make a label out of the current PID structure recorded in
1346 PERLDB_PIDS plus the new PID. They also mark themselves as not having a TTY
1347 yet so the parent will give them one later via C<resetterm()>.
1351 # Save the current contents of the environment; we're about to
1352 # much with it. We'll need this if we have to restart.
1353 $ini_pids = $ENV{PERLDB_PIDS};
1355 if ( defined $ENV{PERLDB_PIDS} ) {
1357 # We're a child. Make us a label out of the current PID structure
1358 # recorded in PERLDB_PIDS plus our (new) PID. Mark us as not having
1359 # a term yet so the parent will give us one later via resetterm().
1361 my $env_pids = $ENV{PERLDB_PIDS};
1362 $pids = "[$env_pids]";
1364 # Unless we are on OpenVMS, all programs under the DCL shell run under
1367 if (($^O eq 'VMS') && ($env_pids =~ /\b$$\b/)) {
1371 $ENV{PERLDB_PIDS} .= "->$$";
1375 } ## end if (defined $ENV{PERLDB_PIDS...
1378 # We're the parent PID. Initialize PERLDB_PID in case we end up with a
1379 # child debugger, and mark us as the parent, so we'll know to set up
1380 # more TTY's is we have to.
1381 $ENV{PERLDB_PIDS} = "$$";
1388 # Sets up $emacs as a synonym for $slave_editor.
1389 *emacs = $slave_editor if $slave_editor; # May be used in afterinit()...
1391 =head2 READING THE RC FILE
1393 The debugger will read a file of initialization options if supplied. If
1394 running interactively, this is C<.perldb>; if not, it's C<perldb.ini>.
1398 # As noted, this test really doesn't check accurately that the debugger
1399 # is running at a terminal or not.
1401 my $dev_tty = '/dev/tty';
1402 $dev_tty = 'TT:' if ($^O eq 'VMS');
1403 if ( -e $dev_tty ) { # this is the wrong metric!
1404 $rcfile = ".perldb";
1407 $rcfile = "perldb.ini";
1412 The debugger does a safety test of the file to be read. It must be owned
1413 either by the current user or root, and must only be writable by the owner.
1417 # This wraps a safety test around "do" to read and evaluate the init file.
1419 # This isn't really safe, because there's a race
1420 # between checking and opening. The solution is to
1421 # open and fstat the handle, but then you have to read and
1422 # eval the contents. But then the silly thing gets
1423 # your lexical scope, which is unfortunate at best.
1427 # Just exactly what part of the word "CORE::" don't you understand?
1428 local $SIG{__WARN__};
1429 local $SIG{__DIE__};
1431 unless ( is_safe_file($file) ) {
1432 CORE::warn <<EO_GRIPE;
1433 perldb: Must not source insecure rcfile $file.
1434 You or the superuser must be the owner, and it must not
1435 be writable by anyone but its owner.
1438 } ## end unless (is_safe_file($file...
1441 CORE::warn("perldb: couldn't parse $file: $@") if $@;
1442 } ## end sub safe_do
1444 # This is the safety test itself.
1446 # Verifies that owner is either real user or superuser and that no
1447 # one but owner may write to it. This function is of limited use
1448 # when called on a path instead of upon a handle, because there are
1449 # no guarantees that filename (by dirent) whose file (by ino) is
1450 # eventually accessed is the same as the one tested.
1451 # Assumes that the file's existence is not in doubt.
1454 stat($path) || return; # mysteriously vaporized
1455 my ( $dev, $ino, $mode, $nlink, $uid, $gid ) = stat(_);
1457 return 0 if $uid != 0 && $uid != $<;
1458 return 0 if $mode & 022;
1460 } ## end sub is_safe_file
1462 # If the rcfile (whichever one we decided was the right one to read)
1463 # exists, we safely do it.
1465 safe_do("./$rcfile");
1468 # If there isn't one here, try the user's home directory.
1469 elsif ( defined $ENV{HOME} && -f "$ENV{HOME}/$rcfile" ) {
1470 safe_do("$ENV{HOME}/$rcfile");
1473 # Else try the login directory.
1474 elsif ( defined $ENV{LOGDIR} && -f "$ENV{LOGDIR}/$rcfile" ) {
1475 safe_do("$ENV{LOGDIR}/$rcfile");
1478 # If the PERLDB_OPTS variable has options in it, parse those out next.
1479 if ( defined $ENV{PERLDB_OPTS} ) {
1480 parse_options( $ENV{PERLDB_OPTS} );
1485 The last thing we do during initialization is determine which subroutine is
1486 to be used to obtain a new terminal when a new debugger is started. Right now,
1487 the debugger only handles TCP sockets, X11, OS/2, amd Mac OS X
1492 # Set up the get_fork_TTY subroutine to be aliased to the proper routine.
1493 # Works if you're running an xterm or xterm-like window, or you're on
1494 # OS/2, or on Mac OS X. This may need some expansion.
1496 if (not defined &get_fork_TTY) # only if no routine exists
1498 if ( defined $remoteport ) {
1499 # Expect an inetd-like server
1500 *get_fork_TTY = \&socket_get_fork_TTY; # to listen to us
1502 elsif (defined $ENV{TERM} # If we know what kind
1503 # of terminal this is,
1504 and $ENV{TERM} eq 'xterm' # and it's an xterm,
1505 and defined $ENV{DISPLAY} # and what display it's on,
1508 *get_fork_TTY = \&xterm_get_fork_TTY; # use the xterm version
1510 elsif ( $^O eq 'os2' ) { # If this is OS/2,
1511 *get_fork_TTY = \&os2_get_fork_TTY; # use the OS/2 version
1513 elsif ( $^O eq 'darwin' # If this is Mac OS X
1514 and defined $ENV{TERM_PROGRAM} # and we're running inside
1515 and $ENV{TERM_PROGRAM}
1516 eq 'Apple_Terminal' # Terminal.app
1519 *get_fork_TTY = \&macosx_get_fork_TTY; # use the Mac OS X version
1521 } ## end if (not defined &get_fork_TTY...
1523 # untaint $^O, which may have been tainted by the last statement.
1524 # see bug [perl #24674]
1528 # Here begin the unreadable code. It needs fixing.
1530 =head2 RESTART PROCESSING
1532 This section handles the restart command. When the C<R> command is invoked, it
1533 tries to capture all of the state it can into environment variables, and
1534 then sets C<PERLDB_RESTART>. When we start executing again, we check to see
1535 if C<PERLDB_RESTART> is there; if so, we reload all the information that
1536 the R command stuffed into the environment variables.
1538 PERLDB_RESTART - flag only, contains no restart data itself.
1539 PERLDB_HIST - command history, if it's available
1540 PERLDB_ON_LOAD - breakpoints set by the rc file
1541 PERLDB_POSTPONE - subs that have been loaded/not executed, and have actions
1542 PERLDB_VISITED - files that had breakpoints
1543 PERLDB_FILE_... - breakpoints for a file
1544 PERLDB_OPT - active options
1545 PERLDB_INC - the original @INC
1546 PERLDB_PRETYPE - preprompt debugger actions
1547 PERLDB_PRE - preprompt Perl code
1548 PERLDB_POST - post-prompt Perl code
1549 PERLDB_TYPEAHEAD - typeahead captured by readline()
1551 We chug through all these variables and plug the values saved in them
1552 back into the appropriate spots in the debugger.
1556 if ( exists $ENV{PERLDB_RESTART} ) {
1558 # We're restarting, so we don't need the flag that says to restart anymore.
1559 delete $ENV{PERLDB_RESTART};
1562 @hist = get_list('PERLDB_HIST');
1563 %break_on_load = get_list("PERLDB_ON_LOAD");
1564 %postponed = get_list("PERLDB_POSTPONE");
1568 share(%break_on_load);
1571 # restore breakpoints/actions
1572 my @had_breakpoints = get_list("PERLDB_VISITED");
1573 for my $file_idx ( 0 .. $#had_breakpoints ) {
1574 my $filename = $had_breakpoints[$file_idx];
1575 my %pf = get_list("PERLDB_FILE_$file_idx");
1576 $postponed_file{ $filename } = \%pf if %pf;
1577 my @lines = sort {$a <=> $b} keys(%pf);
1578 my @enabled_statuses = get_list("PERLDB_FILE_ENABLED_$file_idx");
1579 for my $line_idx (0 .. $#lines) {
1580 _set_breakpoint_enabled_status(
1583 ($enabled_statuses[$line_idx] ? 1 : ''),
1589 my %opt = get_list("PERLDB_OPT");
1591 while ( ( $opt, $val ) = each %opt ) {
1592 $val =~ s/[\\\']/\\$1/g;
1593 parse_options("$opt'$val'");
1596 # restore original @INC
1597 @INC = get_list("PERLDB_INC");
1600 # return pre/postprompt actions and typeahead buffer
1601 $pretype = [ get_list("PERLDB_PRETYPE") ];
1602 $pre = [ get_list("PERLDB_PRE") ];
1603 $post = [ get_list("PERLDB_POST") ];
1604 @typeahead = get_list( "PERLDB_TYPEAHEAD", @typeahead );
1605 } ## end if (exists $ENV{PERLDB_RESTART...
1607 =head2 SETTING UP THE TERMINAL
1609 Now, we'll decide how the debugger is going to interact with the user.
1610 If there's no TTY, we set the debugger to run non-stop; there's not going
1611 to be anyone there to enter commands.
1622 If there is a TTY, we have to determine who it belongs to before we can
1623 proceed. If this is a slave editor or graphical debugger (denoted by
1624 the first command-line switch being '-emacs'), we shift this off and
1625 set C<$rl> to 0 (XXX ostensibly to do straight reads).
1631 # Is Perl being run from a slave editor or graphical debugger?
1632 # If so, don't use readline, and set $slave_editor = 1.
1634 ( ( defined $main::ARGV[0] ) and ( $main::ARGV[0] eq '-emacs' ) );
1635 $rl = 0, shift(@main::ARGV) if $slave_editor;
1637 #require Term::ReadLine;
1641 We then determine what the console should be on various systems:
1645 =item * Cygwin - We use C<stdin> instead of a separate device.
1649 if ( $^O eq 'cygwin' ) {
1651 # /dev/tty is binary. use stdin for textmode
1655 =item * Unix - use C</dev/tty>.
1659 elsif ( -e "/dev/tty" ) {
1660 $console = "/dev/tty";
1663 =item * Windows or MSDOS - use C<con>.
1667 elsif ( $^O eq 'dos' or -e "con" or $^O eq 'MSWin32' ) {
1671 =item * VMS - use C<sys$command>.
1677 # everything else is ...
1678 $console = "sys\$command";
1685 Several other systems don't use a specific console. We C<undef $console>
1686 for those (Windows using a slave editor/graphical debugger, NetWare, OS/2
1687 with a slave editor, Epoc).
1691 if ( ( $^O eq 'MSWin32' ) and ( $slave_editor or defined $ENV{EMACS} ) ) {
1693 # /dev/tty is binary. use stdin for textmode
1697 if ( $^O eq 'NetWare' ) {
1699 # /dev/tty is binary. use stdin for textmode
1703 # In OS/2, we need to use STDIN to get textmode too, even though
1704 # it pretty much looks like Unix otherwise.
1705 if ( defined $ENV{OS2_SHELL} and ( $slave_editor or $ENV{WINDOWID} ) )
1710 # EPOC also falls into the 'got to use STDIN' camp.
1711 if ( $^O eq 'epoc' ) {
1717 If there is a TTY hanging around from a parent, we use that as the console.
1721 $console = $tty if defined $tty;
1723 =head2 SOCKET HANDLING
1725 The debugger is capable of opening a socket and carrying out a debugging
1726 session over the socket.
1728 If C<RemotePort> was defined in the options, the debugger assumes that it
1729 should try to start a debugging session on that port. It builds the socket
1730 and then tries to connect the input and output filehandles to it.
1734 # Handle socket stuff.
1736 if ( defined $remoteport ) {
1738 # If RemotePort was defined in the options, connect input and output
1740 $IN = $OUT = connect_remoteport();
1741 } ## end if (defined $remoteport)
1745 If no C<RemotePort> was defined, and we want to create a TTY on startup,
1746 this is probably a situation where multiple debuggers are running (for example,
1747 a backticked command that starts up another debugger). We create a new IN and
1748 OUT filehandle, and do the necessary mojo to create a new TTY if we know how
1756 # Two debuggers running (probably a system or a backtick that invokes
1757 # the debugger itself under the running one). create a new IN and OUT
1758 # filehandle, and do the necessary mojo to create a new tty if we
1759 # know how, and we can.
1760 create_IN_OUT(4) if $CreateTTY & 4;
1763 # If we have a console, check to see if there are separate ins and
1764 # outs to open. (They are assumed identical if not.)
1766 my ( $i, $o ) = split /,/, $console;
1767 $o = $i unless defined $o;
1769 # read/write on in, or just read, or read on STDIN.
1771 || open( IN, "<$i" )
1772 || open( IN, "<&STDIN" );
1774 # read/write/create/clobber out, or write/create/clobber out,
1775 # or merge with STDERR, or merge with STDOUT.
1777 || open( OUT, ">$o" )
1778 || open( OUT, ">&STDERR" )
1779 || open( OUT, ">&STDOUT" ); # so we don't dongle stdout
1781 } ## end if ($console)
1782 elsif ( not defined $console ) {
1784 # No console. Open STDIN.
1785 open( IN, "<&STDIN" );
1787 # merge with STDERR, or with STDOUT.
1788 open( OUT, ">&STDERR" )
1789 || open( OUT, ">&STDOUT" ); # so we don't dongle stdout
1790 $console = 'STDIN/OUT';
1791 } ## end elsif (not defined $console)
1793 # Keep copies of the filehandles so that when the pager runs, it
1794 # can close standard input without clobbering ours.
1795 $IN = \*IN, $OUT = \*OUT if $console or not defined $console;
1796 } ## end elsif (from if(defined $remoteport))
1798 # Unbuffer DB::OUT. We need to see responses right away.
1799 my $previous = select($OUT);
1800 $| = 1; # for DB::OUT
1803 # Line info goes to debugger output unless pointed elsewhere.
1804 # Pointing elsewhere makes it possible for slave editors to
1805 # keep track of file and position. We have both a filehandle
1806 # and a I/O description to keep track of.
1807 $LINEINFO = $OUT unless defined $LINEINFO;
1808 $lineinfo = $console unless defined $lineinfo;
1809 # share($LINEINFO); # <- unable to share globs
1814 To finish initialization, we show the debugger greeting,
1815 and then call the C<afterinit()> subroutine if there is one.
1819 # Show the debugger greeting.
1820 $header =~ s/.Header: ([^,]+),v(\s+\S+\s+\S+).*$/$1$2/;
1821 unless ($runnonstop) {
1824 if ( $term_pid eq '-1' ) {
1825 print $OUT "\nDaughter DB session started...\n";
1828 print $OUT "\nLoading DB routines from $header\n";
1831 $slave_editor ? "enabled" : "available", ".\n"
1834 "\nEnter h or 'h h' for help, or '$doccmd perldebug' for more help.\n\n";
1835 } ## end else [ if ($term_pid eq '-1')
1836 } ## end unless ($runnonstop)
1837 } ## end else [ if ($notty)
1839 # XXX This looks like a bug to me.
1840 # Why copy to @ARGS and then futz with @args?
1843 # Make sure backslashes before single quotes are stripped out, and
1844 # keep args unless they are numeric (XXX why?)
1845 # s/\'/\\\'/g; # removed while not justified understandably
1846 # s/(.*)/'$1'/ unless /^-?[\d.]+$/; # ditto
1849 # If there was an afterinit() sub defined, call it. It will get
1850 # executed in our scope, so it can fiddle with debugger globals.
1851 if ( defined &afterinit ) { # May be defined in $rcfile
1855 # Inform us about "Stack dump during die enabled ..." in dieLevel().
1858 ############################################################ Subroutines
1864 This gigantic subroutine is the heart of the debugger. Called before every
1865 statement, its job is to determine if a breakpoint has been reached, and
1866 stop if so; read commands from the user, parse them, and execute
1867 them, and then send execution off to the next statement.
1869 Note that the order in which the commands are processed is very important;
1870 some commands earlier in the loop will actually alter the C<$cmd> variable
1871 to create other commands to be executed later. This is all highly I<optimized>
1872 but can be confusing. Check the comments for each C<$cmd ... && do {}> to
1873 see what's happening in any given command.
1879 # lock the debugger and get the thread id for the prompt
1882 if ($ENV{PERL5DB_THREADED}) {
1883 $tid = eval { "[".threads->tid."]" };
1886 # Check for whether we should be running continuously or not.
1887 # _After_ the perl program is compiled, $single is set to 1:
1888 if ( $single and not $second_time++ ) {
1890 # Options say run non-stop. Run until we get an interrupt.
1891 if ($runnonstop) { # Disable until signal
1892 # If there's any call stack in place, turn off single
1893 # stepping into subs throughout the stack.
1894 for ( $i = 0 ; $i <= $stack_depth ; ) {
1895 $stack[ $i++ ] &= ~1;
1898 # And we are now no longer in single-step mode.
1901 # If we simply returned at this point, we wouldn't get
1902 # the trace info. Fall on through.
1904 } ## end if ($runnonstop)
1906 elsif ($ImmediateStop) {
1908 # We are supposed to stop here; XXX probably a break.
1909 $ImmediateStop = 0; # We've processed it; turn it off
1910 $signal = 1; # Simulate an interrupt to force
1911 # us into the command loop
1913 } ## end if ($single and not $second_time...
1915 # If we're in single-step mode, or an interrupt (real or fake)
1916 # has occurred, turn off non-stop mode.
1917 $runnonstop = 0 if $single or $signal;
1919 # Preserve current values of $@, $!, $^E, $,, $/, $\, $^W.
1920 # The code being debugged may have altered them.
1923 # Since DB::DB gets called after every line, we can use caller() to
1924 # figure out where we last were executing. Sneaky, eh? This works because
1925 # caller is returning all the extra information when called from the
1927 local ( $package, $filename, $line ) = caller;
1928 local $filename_ini = $filename;
1930 # set up the context for DB::eval, so it can properly execute
1931 # code on behalf of the user. We add the package in so that the
1932 # code is eval'ed in the proper package (not in the debugger!).
1933 local $usercontext =
1934 '($@, $!, $^E, $,, $/, $\, $^W) = @saved;' . "package $package;";
1936 # Create an alias to the active file magical array to simplify
1938 local (*dbline) = $main::{ '_<' . $filename };
1940 # Last line in the program.
1941 local $max = $#dbline;
1943 # if we have something here, see if we should break.
1945 && _is_breakpoint_enabled($filename, $line)
1946 && ( ( $stop, $action ) = split( /\0/, $dbline{$line} ) ) )
1949 # Stop if the stop criterion says to just stop.
1950 if ( $stop eq '1' ) {
1954 # It's a conditional stop; eval it in the user's context and
1955 # see if we should stop. If so, remove the one-time sigil.
1957 $evalarg = "\$DB::signal |= 1 if do {$stop}";
1959 # If the breakpoint is temporary, then delete its enabled status.
1960 if ($dbline{$line} =~ s/;9($|\0)/$1/) {
1961 _cancel_breakpoint_temp_enabled_status($filename, $line);
1964 } ## end if ($dbline{$line} && ...
1966 # Preserve the current stop-or-not, and see if any of the W
1967 # (watch expressions) has changed.
1968 my $was_signal = $signal;
1970 # If we have any watch expressions ...
1972 for ( my $n = 0 ; $n <= $#to_watch ; $n++ ) {
1973 $evalarg = $to_watch[$n];
1974 local $onetimeDump; # Tell DB::eval() to not output results
1976 # Fix context DB::eval() wants to return an array, but
1977 # we need a scalar here.
1978 my ($val) = join( "', '", &eval );
1979 $val = ( ( defined $val ) ? "'$val'" : 'undef' );
1982 if ( $val ne $old_watch[$n] ) {
1984 # Yep! Show the difference, and fake an interrupt.
1987 Watchpoint $n:\t$to_watch[$n] changed:
1988 old value:\t$old_watch[$n]
1991 $old_watch[$n] = $val;
1992 } ## end if ($val ne $old_watch...
1993 } ## end for (my $n = 0 ; $n <= ...
1994 } ## end if ($trace & 2)
1996 =head2 C<watchfunction()>
1998 C<watchfunction()> is a function that can be defined by the user; it is a
1999 function which will be run on each entry to C<DB::DB>; it gets the
2000 current package, filename, and line as its parameters.
2002 The watchfunction can do anything it likes; it is executing in the
2003 debugger's context, so it has access to all of the debugger's internal
2004 data structures and functions.
2006 C<watchfunction()> can control the debugger's actions. Any of the following
2007 will cause the debugger to return control to the user's program after
2008 C<watchfunction()> executes:
2014 Returning a false value from the C<watchfunction()> itself.
2018 Altering C<$single> to a false value.
2022 Altering C<$signal> to a false value.
2026 Turning off the C<4> bit in C<$trace> (this also disables the
2027 check for C<watchfunction()>. This can be done with
2035 # If there's a user-defined DB::watchfunction, call it with the
2036 # current package, filename, and line. The function executes in
2038 if ( $trace & 4 ) { # User-installed watch
2040 if watchfunction( $package, $filename, $line )
2043 and not( $trace & ~4 );
2044 } ## end if ($trace & 4)
2046 # Pick up any alteration to $signal in the watchfunction, and
2047 # turn off the signal now.
2048 $was_signal = $signal;
2051 =head2 GETTING READY TO EXECUTE COMMANDS
2053 The debugger decides to take control if single-step mode is on, the
2054 C<t> command was entered, or the user generated a signal. If the program
2055 has fallen off the end, we set things up so that entering further commands
2056 won't cause trouble, and we say that the program is over.
2060 # Make sure that we always print if asked for explicitly regardless
2061 # of $trace_to_depth .
2062 my $explicit_stop = ($single || $was_signal);
2064 # Check to see if we should grab control ($single true,
2065 # trace set appropriately, or we got a signal).
2066 if ( $explicit_stop || ( $trace & 1 ) ) {
2068 # Yes, grab control.
2069 if ($slave_editor) {
2071 # Tell the editor to update its position.
2072 $position = "\032\032$filename:$line:0\n";
2073 print_lineinfo($position);
2078 Special check: if we're in package C<DB::fake>, we've gone through the
2079 C<END> block at least once. We set up everything so that we can continue
2080 to enter commands and have a valid context to be in.
2084 elsif ( $package eq 'DB::fake' ) {
2086 # Fallen off the end already.
2089 Debugged program terminated. Use B<q> to quit or B<R> to restart,
2090 use B<o> I<inhibit_exit> to avoid stopping after program termination,
2091 B<h q>, B<h R> or B<h o> to get additional info.
2094 # Set the DB::eval context appropriately.
2097 '($@, $!, $^E, $,, $/, $\, $^W) = @saved;'
2098 . "package $package;"; # this won't let them modify, alas
2099 } ## end elsif ($package eq 'DB::fake')
2103 If the program hasn't finished executing, we scan forward to the
2104 next executable line, print that out, build the prompt from the file and line
2105 number information, and print that.
2112 # Still somewhere in the midst of execution. Set up the
2114 $sub =~ s/\'/::/; # Swap Perl 4 package separators (') to
2115 # Perl 5 ones (sorry, we don't print Klingon
2118 $prefix = $sub =~ /::/ ? "" : "${'package'}::";
2119 $prefix .= "$sub($filename:";
2120 $after = ( $dbline[$line] =~ /\n$/ ? '' : "\n" );
2122 # Break up the prompt if it's really long.
2123 if ( length($prefix) > 30 ) {
2124 $position = "$prefix$line):\n$line:\t$dbline[$line]$after";
2130 $position = "$prefix$line$infix$dbline[$line]$after";
2133 # Print current line info, indenting if necessary.
2135 print_lineinfo( ' ' x $stack_depth,
2136 "$line:\t$dbline[$line]$after" );
2139 depth_print_lineinfo($explicit_stop, $position);
2142 # Scan forward, stopping at either the end or the next
2144 for ( $i = $line + 1 ; $i <= $max && $dbline[$i] == 0 ; ++$i )
2147 # Drop out on null statements, block closers, and comments.
2148 last if $dbline[$i] =~ /^\s*[\;\}\#\n]/;
2150 # Drop out if the user interrupted us.
2153 # Append a newline if the line doesn't have one. Can happen
2154 # in eval'ed text, for instance.
2155 $after = ( $dbline[$i] =~ /\n$/ ? '' : "\n" );
2157 # Next executable line.
2158 $incr_pos = "$prefix$i$infix$dbline[$i]$after";
2159 $position .= $incr_pos;
2162 # Print it indented if tracing is on.
2163 print_lineinfo( ' ' x $stack_depth,
2164 "$i:\t$dbline[$i]$after" );
2167 depth_print_lineinfo($explicit_stop, $incr_pos);
2169 } ## end for ($i = $line + 1 ; $i...
2170 } ## end else [ if ($slave_editor)
2171 } ## end if ($single || ($trace...
2175 If there's an action to be executed for the line we stopped at, execute it.
2176 If there are any preprompt actions, execute those as well.
2180 # If there's an action, do it now.
2181 $evalarg = $action, &eval if $action;
2183 # Are we nested another level (e.g., did we evaluate a function
2184 # that had a breakpoint in it at the debugger prompt)?
2185 if ( $single || $was_signal ) {
2187 # Yes, go down a level.
2188 local $level = $level + 1;
2190 # Do any pre-prompt actions.
2191 foreach $evalarg (@$pre) {
2195 # Complain about too much recursion if we passed the limit.
2196 print $OUT $stack_depth . " levels deep in subroutine calls!\n"
2199 # The line we're currently on. Set $incr to -1 to stay here
2200 # until we get a command that tells us to advance.
2202 $incr = -1; # for backward motion.
2204 # Tack preprompt debugger actions ahead of any actual input.
2205 @typeahead = ( @$pretype, @typeahead );
2207 =head2 WHERE ARE WE?
2209 XXX Relocate this section?
2211 The debugger normally shows the line corresponding to the current line of
2212 execution. Sometimes, though, we want to see the next line, or to move elsewhere
2213 in the file. This is done via the C<$incr>, C<$start>, and C<$max> variables.
2215 C<$incr> controls by how many lines the I<current> line should move forward
2216 after a command is executed. If set to -1, this indicates that the I<current>
2217 line shouldn't change.
2219 C<$start> is the I<current> line. It is used for things like knowing where to
2220 move forwards or backwards from when doing an C<L> or C<-> command.
2222 C<$max> tells the debugger where the last line of the current file is. It's
2223 used to terminate loops most often.
2225 =head2 THE COMMAND LOOP
2227 Most of C<DB::DB> is actually a command parsing and dispatch loop. It comes
2234 The outer part of the loop, starting at the C<CMD> label. This loop
2235 reads a command and then executes it.
2239 The inner part of the loop, starting at the C<PIPE> label. This part
2240 is wholly contained inside the C<CMD> block and only executes a command.
2241 Used to handle commands running inside a pager.
2245 So why have two labels to restart the loop? Because sometimes, it's easier to
2246 have a command I<generate> another command and then re-execute the loop to do
2247 the new command. This is faster, but perhaps a bit more convoluted.
2251 # The big command dispatch loop. It keeps running until the
2252 # user yields up control again.
2254 # If we have a terminal for input, and we get something back
2255 # from readline(), keep on processing.
2259 # We have a terminal, or can get one ...
2260 ( $term || &setterm ),
2262 # ... and it belogs to this PID or we get one for this PID ...
2263 ( $term_pid == $$ or resetterm(1) ),
2265 # ... and we got a line of command input ...
2268 "$pidprompt $tid DB"
2271 . ( '>' x $level ) . " "
2278 # ... try to execute the input as debugger commands.
2280 # Don't stop running.
2283 # No signal is active.
2286 # Handle continued commands (ending with \):
2287 $cmd =~ s/\\$/\n/ && do {
2288 $cmd .= &readline(" cont: ");
2292 =head4 The null command
2294 A newline entered by itself means I<re-execute the last command>. We grab the
2295 command out of C<$laststep> (where it was recorded previously), and copy it
2296 back into C<$cmd> to be executed below. If there wasn't any previous command,
2297 we'll do nothing below (no command will match). If there was, we also save it
2298 in the command history and fall through to allow the command parsing to pick
2303 # Empty input means repeat the last command.
2304 $cmd =~ /^$/ && ( $cmd = $laststep );
2305 chomp($cmd); # get rid of the annoying extra newline
2306 push( @hist, $cmd ) if length($cmd) > 1;
2307 push( @truehist, $cmd );
2311 # This is a restart point for commands that didn't arrive
2312 # via direct user input. It allows us to 'redo PIPE' to
2313 # re-execute command processing without reading a new command.
2315 $cmd =~ s/^\s+//s; # trim annoying leading whitespace
2316 $cmd =~ s/\s+$//s; # trim annoying trailing whitespace
2317 ($i) = split( /\s+/, $cmd );
2319 =head3 COMMAND ALIASES
2321 The debugger can create aliases for commands (these are stored in the
2322 C<%alias> hash). Before a command is executed, the command loop looks it up
2323 in the alias hash and substitutes the contents of the alias for the command,
2324 completely replacing it.
2328 # See if there's an alias for the command, and set it up if so.
2331 # Squelch signal handling; we want to keep control here
2332 # if something goes loco during the alias eval.
2333 local $SIG{__DIE__};
2334 local $SIG{__WARN__};
2336 # This is a command, so we eval it in the DEBUGGER's
2337 # scope! Otherwise, we can't see the special debugger
2338 # variables, or get to the debugger's subs. (Well, we
2339 # _could_, but why make it even more complicated?)
2340 eval "\$cmd =~ $alias{$i}";
2343 print $OUT "Couldn't evaluate '$i' alias: $@";
2346 } ## end if ($alias{$i})
2348 =head3 MAIN-LINE COMMANDS
2350 All of these commands work up to and after the program being debugged has
2355 Quit the debugger. This entails setting the C<$fall_off_end> flag, so we don't
2356 try to execute further, cleaning any restart-related stuff out of the
2357 environment, and executing with the last value of C<$?>.
2361 $cmd =~ /^q$/ && do {
2367 =head4 C<t> - trace [n]
2369 Turn tracing on or off. Inverts the appropriate bit in C<$trace> (q.v.).
2370 If level is specified, set C<$trace_to_depth>.
2374 $cmd =~ /^t(?:\s+(\d+))?$/ && do {
2378 $trace_to_depth = $levels ? $stack_depth + $levels : 1E9;
2379 print $OUT "Trace = "
2381 ? ( $levels ? "on (to level $trace_to_depth)" : "on" )
2386 =head4 C<S> - list subroutines matching/not matching a pattern
2388 Walks through C<%sub>, checking to see whether or not to print the name.
2392 $cmd =~ /^S(\s+(!)?(.+))?$/ && do {
2394 $Srev = defined $2; # Reverse scan?
2395 $Spatt = $3; # The pattern (if any) to use.
2396 $Snocheck = !defined $1; # No args - print all subs.
2398 # Need to make these sane here.
2402 # Search through the debugger's magical hash of subs.
2403 # If $nocheck is true, just print the sub name.
2404 # Otherwise, check it against the pattern. We then use
2405 # the XOR trick to reverse the condition as required.
2406 foreach $subname ( sort( keys %sub ) ) {
2407 if ( $Snocheck or $Srev ^ ( $subname =~ /$Spatt/ ) ) {
2408 print $OUT $subname, "\n";
2414 =head4 C<X> - list variables in current package
2416 Since the C<V> command actually processes this, just change this to the
2417 appropriate C<V> command and fall through.
2421 $cmd =~ s/^X\b/V $package/;
2423 =head4 C<V> - list variables
2425 Uses C<dumpvar.pl> to dump out the current values for selected variables.
2429 # Bare V commands get the currently-being-debugged package
2431 $cmd =~ /^V$/ && do {
2432 $cmd = "V $package";
2435 # V - show variables in package.
2436 $cmd =~ /^V\b\s*(\S+)\s*(.*)/ && do {
2438 # Save the currently selected filehandle and
2439 # force output to debugger's filehandle (dumpvar
2440 # just does "print" for output).
2441 local ($savout) = select($OUT);
2443 # Grab package name and variables to dump.
2445 @vars = split( ' ', $2 );
2447 # If main::dumpvar isn't here, get it.
2448 do 'dumpvar.pl' || die $@ unless defined &main::dumpvar;
2449 if ( defined &main::dumpvar ) {
2451 # We got it. Turn off subroutine entry/exit messages
2452 # for the moment, along with return values.
2456 # must detect sigpipe failures - not catching
2457 # then will cause the debugger to die.
2461 defined $option{dumpDepth}
2462 ? $option{dumpDepth}
2463 : -1, # assume -1 unless specified
2468 # The die doesn't need to include the $@, because
2469 # it will automatically get propagated for us.
2471 die unless $@ =~ /dumpvar print failed/;
2473 } ## end if (defined &main::dumpvar)
2476 # Couldn't load dumpvar.
2477 print $OUT "dumpvar.pl not available.\n";
2480 # Restore the output filehandle, and go round again.
2485 =head4 C<x> - evaluate and print an expression
2487 Hands the expression off to C<DB::eval>, setting it up to print the value
2488 via C<dumpvar.pl> instead of just printing it directly.
2492 $cmd =~ s/^x\b/ / && do { # Remainder gets done by DB::eval()
2493 $onetimeDump = 'dump'; # main::dumpvar shows the output
2495 # handle special "x 3 blah" syntax XXX propagate
2496 # doc back to special variables.
2497 if ( $cmd =~ s/^\s*(\d+)(?=\s)/ / ) {
2498 $onetimedumpDepth = $1;
2502 =head4 C<m> - print methods
2504 Just uses C<DB::methods> to determine what methods are available.
2508 $cmd =~ s/^m\s+([\w:]+)\s*$/ / && do {
2513 # m expr - set up DB::eval to do the work
2514 $cmd =~ s/^m\b/ / && do { # Rest gets done by DB::eval()
2515 $onetimeDump = 'methods'; # method output gets used there
2518 =head4 C<f> - switch files
2522 $cmd =~ /^f\b\s*(.*)/ && do {
2526 # help for no arguments (old-style was return from sub).
2529 "The old f command is now the r command.\n"; # hint
2530 print $OUT "The new f command switches filenames.\n";
2532 } ## end if (!$file)
2534 # if not in magic file list, try a close match.
2535 if ( !defined $main::{ '_<' . $file } ) {
2536 if ( ($try) = grep( m#^_<.*$file#, keys %main:: ) ) {
2538 $try = substr( $try, 2 );
2539 print $OUT "Choosing $try matching '$file':\n";
2542 } ## end if (($try) = grep(m#^_<.*$file#...
2543 } ## end if (!defined $main::{ ...
2545 # If not successfully switched now, we failed.
2546 if ( !defined $main::{ '_<' . $file } ) {
2547 print $OUT "No file matching '$file' is loaded.\n";
2551 # We switched, so switch the debugger internals around.
2552 elsif ( $file ne $filename ) {
2553 *dbline = $main::{ '_<' . $file };
2558 } ## end elsif ($file ne $filename)
2560 # We didn't switch; say we didn't.
2562 print $OUT "Already in $file.\n";
2567 =head4 C<.> - return to last-executed line.
2569 We set C<$incr> to -1 to indicate that the debugger shouldn't move ahead,
2570 and then we look up the line in the magical C<%dbline> hash.
2575 $cmd =~ /^\.$/ && do {
2576 $incr = -1; # stay at current line
2578 # Reset everything to the old location.
2580 $filename = $filename_ini;
2581 *dbline = $main::{ '_<' . $filename };
2585 print_lineinfo($position);
2589 =head4 C<-> - back one window
2591 We change C<$start> to be one window back; if we go back past the first line,
2592 we set it to be the first line. We ser C<$incr> to put us back at the
2593 currently-executing line, and then put a C<l $start +> (list one window from
2594 C<$start>) in C<$cmd> to be executed later.
2598 # - - back a window.
2599 $cmd =~ /^-$/ && do {
2601 # back up by a window; go to 1 if back too far.
2602 $start -= $incr + $window + 1;
2603 $start = 1 if $start <= 0;
2604 $incr = $window - 1;
2606 # Generate and execute a "l +" command (handled below).
2607 $cmd = 'l ' . ($start) . '+';
2610 =head3 PRE-580 COMMANDS VS. NEW COMMANDS: C<a, A, b, B, h, l, L, M, o, O, P, v, w, W, E<lt>, E<lt>E<lt>, {, {{>
2612 In Perl 5.8.0, a realignment of the commands was done to fix up a number of
2613 problems, most notably that the default case of several commands destroying
2614 the user's work in setting watchpoints, actions, etc. We wanted, however, to
2615 retain the old commands for those who were used to using them or who preferred
2616 them. At this point, we check for the new commands and call C<cmd_wrapper> to
2617 deal with them instead of processing them in-line.
2621 # All of these commands were remapped in perl 5.8.0;
2622 # we send them off to the secondary dispatcher (see below).
2623 $cmd =~ /^([aAbBeEhilLMoOPvwW]\b|[<>\{]{1,2})\s*(.*)/so && do {
2624 &cmd_wrapper( $1, $2, $line );
2628 =head4 C<y> - List lexicals in higher scope
2630 Uses C<PadWalker> to find the lexicals supplied as arguments in a scope
2631 above the current one and then displays then using C<dumpvar.pl>.
2635 $cmd =~ /^y(?:\s+(\d*)\s*(.*))?$/ && do {
2637 # See if we've got the necessary support.
2638 eval { require PadWalker; PadWalker->VERSION(0.08) }
2641 ? "PadWalker module not found - please install\n"
2646 # Load up dumpvar if we don't have it. If we can, that is.
2647 do 'dumpvar.pl' || die $@ unless defined &main::dumpvar;
2648 defined &main::dumpvar
2649 or print $OUT "dumpvar.pl not available.\n"
2652 # Got all the modules we need. Find them and print them.
2653 my @vars = split( ' ', $2 || '' );
2656 my $h = eval { PadWalker::peek_my( ( $1 || 0 ) + 1 ) };
2658 # Oops. Can't find it.
2659 $@ and $@ =~ s/ at .*//, &warn($@), next CMD;
2661 # Show the desired vars with dumplex().
2662 my $savout = select($OUT);
2664 # Have dumplex dump the lexicals.
2665 dumpvar::dumplex( $_, $h->{$_},
2666 defined $option{dumpDepth} ? $option{dumpDepth} : -1,
2673 =head3 COMMANDS NOT WORKING AFTER PROGRAM ENDS
2675 All of the commands below this point don't work after the program being
2676 debugged has ended. All of them check to see if the program has ended; this
2677 allows the commands to be relocated without worrying about a 'line of
2678 demarcation' above which commands can be entered anytime, and below which
2681 =head4 C<n> - single step, but don't trace down into subs
2683 Done by setting C<$single> to 2, which forces subs to execute straight through
2684 when entered (see C<DB::sub>). We also save the C<n> command in C<$laststep>,
2685 so a null command knows what to re-execute.
2690 $cmd =~ /^n$/ && do {
2691 end_report(), next CMD if $finished and $level <= 1;
2693 # Single step, but don't enter subs.
2696 # Save for empty command (repeat last).
2701 =head4 C<s> - single-step, entering subs
2703 Sets C<$single> to 1, which causes C<DB::sub> to continue tracing inside
2704 subs. Also saves C<s> as C<$lastcmd>.
2709 $cmd =~ /^s$/ && do {
2711 # Get out and restart the command loop if program
2713 end_report(), next CMD if $finished and $level <= 1;
2715 # Single step should enter subs.
2718 # Save for empty command (repeat last).
2723 =head4 C<c> - run continuously, setting an optional breakpoint
2725 Most of the code for this command is taken up with locating the optional
2726 breakpoint, which is either a subroutine name or a line number. We set
2727 the appropriate one-time-break in C<@dbline> and then turn off single-stepping
2728 in this and all call levels above this one.
2732 # c - start continuous execution.
2733 $cmd =~ /^c\b\s*([\w:]*)\s*$/ && do {
2735 # Hey, show's over. The debugged program finished
2736 # executing already.
2737 end_report(), next CMD if $finished and $level <= 1;
2739 # Capture the place to put a one-time break.
2742 # Probably not needed, since we finish an interactive
2743 # sub-session anyway...
2744 # local $filename = $filename;
2745 # local *dbline = *dbline; # XXX Would this work?!
2747 # The above question wonders if localizing the alias
2748 # to the magic array works or not. Since it's commented
2749 # out, we'll just leave that to speculation for now.
2751 # If the "subname" isn't all digits, we'll assume it
2752 # is a subroutine name, and try to find it.
2753 if ( $subname =~ /\D/ ) { # subroutine name
2754 # Qualify it to the current package unless it's
2755 # already qualified.
2756 $subname = $package . "::" . $subname
2757 unless $subname =~ /::/;
2759 # find_sub will return "file:line_number" corresponding
2760 # to where the subroutine is defined; we call find_sub,
2761 # break up the return value, and assign it in one
2763 ( $file, $i ) = ( find_sub($subname) =~ /^(.*):(.*)$/ );
2765 # Force the line number to be numeric.
2768 # If we got a line number, we found the sub.
2771 # Switch all the debugger's internals around so
2772 # we're actually working with that file.
2774 *dbline = $main::{ '_<' . $filename };
2776 # Mark that there's a breakpoint in this file.
2777 $had_breakpoints{$filename} |= 1;
2779 # Scan forward to the first executable line
2780 # after the 'sub whatever' line.
2782 ++$i while $dbline[$i] == 0 && $i < $max;
2785 # We didn't find a sub by that name.
2787 print $OUT "Subroutine $subname not found.\n";
2790 } ## end if ($subname =~ /\D/)
2792 # At this point, either the subname was all digits (an
2793 # absolute line-break request) or we've scanned through
2794 # the code following the definition of the sub, looking
2795 # for an executable, which we may or may not have found.
2797 # If $i (which we set $subname from) is non-zero, we
2798 # got a request to break at some line somewhere. On
2799 # one hand, if there wasn't any real subroutine name
2800 # involved, this will be a request to break in the current
2801 # file at the specified line, so we have to check to make
2802 # sure that the line specified really is breakable.
2804 # On the other hand, if there was a subname supplied, the
2805 # preceding block has moved us to the proper file and
2806 # location within that file, and then scanned forward
2807 # looking for the next executable line. We have to make
2808 # sure that one was found.
2810 # On the gripping hand, we can't do anything unless the
2811 # current value of $i points to a valid breakable line.
2816 if ( $dbline[$i] == 0 ) {
2817 print $OUT "Line $i not breakable.\n";
2821 # Yes. Set up the one-time-break sigil.
2822 $dbline{$i} =~ s/($|\0)/;9$1/; # add one-time-only b.p.
2823 _enable_breakpoint_temp_enabled_status($filename, $i);
2826 # Turn off stack tracing from here up.
2827 for ( $i = 0 ; $i <= $stack_depth ; ) {
2828 $stack[ $i++ ] &= ~1;
2833 =head4 C<r> - return from a subroutine
2835 For C<r> to work properly, the debugger has to stop execution again
2836 immediately after the return is executed. This is done by forcing
2837 single-stepping to be on in the call level above the current one. If
2838 we are printing return values when a C<r> is executed, set C<$doret>
2839 appropriately, and force us out of the command loop.
2843 # r - return from the current subroutine.
2844 $cmd =~ /^r$/ && do {
2846 # Can't do anything if the program's over.
2847 end_report(), next CMD if $finished and $level <= 1;
2849 # Turn on stack trace.
2850 $stack[$stack_depth] |= 1;
2852 # Print return value unless the stack is empty.
2853 $doret = $option{PrintRet} ? $stack_depth - 1 : -2;
2857 =head4 C<T> - stack trace
2859 Just calls C<DB::print_trace>.
2863 $cmd =~ /^T$/ && do {
2864 print_trace( $OUT, 1 ); # skip DB
2868 =head4 C<w> - List window around current line.
2870 Just calls C<DB::cmd_w>.
2874 $cmd =~ /^w\b\s*(.*)/s && do { &cmd_w( 'w', $1 ); next CMD; };
2876 =head4 C<W> - watch-expression processing.
2878 Just calls C<DB::cmd_W>.
2882 $cmd =~ /^W\b\s*(.*)/s && do { &cmd_W( 'W', $1 ); next CMD; };
2884 =head4 C</> - search forward for a string in the source
2886 We take the argument and treat it as a pattern. If it turns out to be a
2887 bad one, we return the error we got from trying to C<eval> it and exit.
2888 If not, we create some code to do the search and C<eval> it so it can't
2893 $cmd =~ /^\/(.*)$/ && do {
2895 # The pattern as a string.
2898 # Remove the final slash.
2899 $inpat =~ s:([^\\])/$:$1:;
2901 # If the pattern isn't null ...
2902 if ( $inpat ne "" ) {
2904 # Turn of warn and die procesing for a bit.
2905 local $SIG{__DIE__};
2906 local $SIG{__WARN__};
2908 # Create the pattern.
2909 eval '$inpat =~ m' . "\a$inpat\a";
2912 # Oops. Bad pattern. No biscuit.
2913 # Print the eval error and go back for more
2919 } ## end if ($inpat ne "")
2921 # Set up to stop on wrap-around.
2924 # Don't move off the current line.
2927 # Done in eval so nothing breaks if the pattern
2928 # does something weird.
2931 # Move ahead one line.
2934 # Wrap if we pass the last line.
2935 $start = 1 if ($start > $max);
2937 # Stop if we have gotten back to this line again,
2938 last if ($start == $end);
2940 # A hit! (Note, though, that we are doing
2941 # case-insensitive matching. Maybe a qr//
2942 # expression would be better, so the user could
2943 # do case-sensitive matching if desired.
2944 if ($dbline[$start] =~ m' . "\a$pat\a" . 'i) {
2945 if ($slave_editor) {
2946 # Handle proper escaping in the slave.
2947 print $OUT "\032\032$filename:$start:0\n";
2950 # Just print the line normally.
2951 print $OUT "$start:\t",$dbline[$start],"\n";
2953 # And quit since we found something.
2958 # If we wrapped, there never was a match.
2959 print $OUT "/$pat/: not found\n" if ( $start == $end );
2963 =head4 C<?> - search backward for a string in the source
2965 Same as for C</>, except the loop runs backwards.
2969 # ? - backward pattern search.
2970 $cmd =~ /^\?(.*)$/ && do {
2972 # Get the pattern, remove trailing question mark.
2974 $inpat =~ s:([^\\])\?$:$1:;
2976 # If we've got one ...
2977 if ( $inpat ne "" ) {
2979 # Turn off die & warn handlers.
2980 local $SIG{__DIE__};
2981 local $SIG{__WARN__};
2982 eval '$inpat =~ m' . "\a$inpat\a";
2986 # Ouch. Not good. Print the error.
2991 } ## end if ($inpat ne "")
2993 # Where we are now is where to stop after wraparound.
2996 # Don't move away from this line.
2999 # Search inside the eval to prevent pattern badness
3006 # Wrap if we pass the first line.
3008 $start = $max if ($start <= 0);
3010 # Quit if we get back where we started,
3011 last if ($start == $end);
3014 if ($dbline[$start] =~ m' . "\a$pat\a" . 'i) {
3015 if ($slave_editor) {
3016 # Yep, follow slave editor requirements.
3017 print $OUT "\032\032$filename:$start:0\n";
3020 # Yep, just print normally.
3021 print $OUT "$start:\t",$dbline[$start],"\n";
3029 # Say we failed if the loop never found anything,
3030 print $OUT "?$pat?: not found\n" if ( $start == $end );
3034 =head4 C<$rc> - Recall command
3036 Manages the commands in C<@hist> (which is created if C<Term::ReadLine> reports
3037 that the terminal supports history). It find the the command required, puts it
3038 into C<$cmd>, and redoes the loop to execute it.
3042 # $rc - recall command.
3043 $cmd =~ /^$rc+\s*(-)?(\d+)?$/ && do {
3045 # No arguments, take one thing off history.
3046 pop(@hist) if length($cmd) > 1;
3048 # Relative (- found)?
3049 # Y - index back from most recent (by 1 if bare minus)
3050 # N - go to that particular command slot or the last
3051 # thing if nothing following.
3052 $i = $1 ? ( $#hist - ( $2 || 1 ) ) : ( $2 || $#hist );
3054 # Pick out the command desired.
3057 # Print the command to be executed and restart the loop
3058 # with that command in the buffer.
3059 print $OUT $cmd, "\n";
3063 =head4 C<$sh$sh> - C<system()> command
3065 Calls the C<DB::system()> to handle the command. This keeps the C<STDIN> and
3066 C<STDOUT> from getting messed up.
3070 # $sh$sh - run a shell command (if it's all ASCII).
3071 # Can't run shell commands with Unicode in the debugger, hmm.
3072 $cmd =~ /^$sh$sh\s*([\x00-\xff]*)/ && do {
3079 =head4 C<$rc I<pattern> $rc> - Search command history
3081 Another command to manipulate C<@hist>: this one searches it with a pattern.
3082 If a command is found, it is placed in C<$cmd> and executed via C<redo>.
3086 # $rc pattern $rc - find a command in the history.
3087 $cmd =~ /^$rc([^$rc].*)$/ && do {
3089 # Create the pattern to use.
3092 # Toss off last entry if length is >1 (and it always is).
3093 pop(@hist) if length($cmd) > 1;
3095 # Look backward through the history.
3096 for ( $i = $#hist ; $i ; --$i ) {
3098 # Stop if we find it.
3099 last if $hist[$i] =~ /$pat/;
3105 print $OUT "No such command!\n\n";
3109 # Found it. Put it in the buffer, print it, and process it.
3111 print $OUT $cmd, "\n";
3115 =head4 C<$sh> - Invoke a shell
3117 Uses C<DB::system> to invoke a shell.
3121 # $sh - start a shell.
3122 $cmd =~ /^$sh$/ && do {
3124 # Run the user's shell. If none defined, run Bourne.
3125 # We resume execution when the shell terminates.
3126 &system( $ENV{SHELL} || "/bin/sh" );
3130 =head4 C<$sh I<command>> - Force execution of a command in a shell
3132 Like the above, but the command is passed to the shell. Again, we use
3133 C<DB::system> to avoid problems with C<STDIN> and C<STDOUT>.
3137 # $sh command - start a shell and run a command in it.
3138 $cmd =~ /^$sh\s*([\x00-\xff]*)/ && do {
3140 # XXX: using csh or tcsh destroys sigint retvals!
3141 #&system($1); # use this instead
3143 # use the user's shell, or Bourne if none defined.
3144 &system( $ENV{SHELL} || "/bin/sh", "-c", $1 );
3148 =head4 C<H> - display commands in history
3150 Prints the contents of C<@hist> (if any).
3154 $cmd =~ /^H\b\s*\*/ && do {
3155 @hist = @truehist = ();
3156 print $OUT "History cleansed\n";
3160 $cmd =~ /^H\b\s*(-(\d+))?/ && do {
3162 # Anything other than negative numbers is ignored by
3163 # the (incorrect) pattern, so this test does nothing.
3164 $end = $2 ? ( $#hist - $2 ) : 0;
3166 # Set to the minimum if less than zero.
3167 $hist = 0 if $hist < 0;
3169 # Start at the end of the array.
3170 # Stay in while we're still above the ending value.
3171 # Tick back by one each time around the loop.
3172 for ( $i = $#hist ; $i > $end ; $i-- ) {
3174 # Print the command unless it has no arguments.
3175 print $OUT "$i: ", $hist[$i], "\n"
3176 unless $hist[$i] =~ /^.?$/;
3181 =head4 C<man, doc, perldoc> - look up documentation
3183 Just calls C<runman()> to print the appropriate document.
3187 # man, perldoc, doc - show manual pages.
3188 $cmd =~ /^(?:man|(?:perl)?doc)\b(?:\s+([^(]*))?$/ && do {
3195 Builds a C<print EXPR> expression in the C<$cmd>; this will get executed at
3196 the bottom of the loop.
3200 # p - print (no args): print $_.
3201 $cmd =~ s/^p$/print {\$DB::OUT} \$_/;
3203 # p - print the given expression.
3204 $cmd =~ s/^p\b/print {\$DB::OUT} /;
3206 =head4 C<=> - define command alias
3208 Manipulates C<%alias> to add or list command aliases.
3212 # = - set up a command alias.
3213 $cmd =~ s/^=\s*// && do {
3215 if ( length $cmd == 0 ) {
3217 # No args, get current aliases.
3218 @keys = sort keys %alias;
3220 elsif ( my ( $k, $v ) = ( $cmd =~ /^(\S+)\s+(\S.*)/ ) ) {
3222 # Creating a new alias. $k is alias name, $v is
3225 # can't use $_ or kill //g state
3226 for my $x ( $k, $v ) {
3228 # Escape "alarm" characters.
3232 # Substitute key for value, using alarm chars
3233 # as separators (which is why we escaped them in
3235 $alias{$k} = "s\a$k\a$v\a";
3237 # Turn off standard warn and die behavior.
3238 local $SIG{__DIE__};
3239 local $SIG{__WARN__};
3242 unless ( eval "sub { s\a$k\a$v\a }; 1" ) {
3244 # Nope. Bad alias. Say so and get out.
3245 print $OUT "Can't alias $k to $v: $@\n";
3250 # We'll only list the new one.
3252 } ## end elsif (my ($k, $v) = ($cmd...
3254 # The argument is the alias to list.
3262 # Messy metaquoting: Trim the substitution code off.
3263 # We use control-G as the delimiter because it's not
3264 # likely to appear in the alias.
3265 if ( ( my $v = $alias{$k} ) =~ s
\as\a$k\a(.*)\a$
\a1
\a ) {
3268 print $OUT "$k\t= $1\n";
3270 elsif ( defined $alias{$k} ) {
3272 # Couldn't trim it off; just print the alias code.
3273 print $OUT "$k\t$alias{$k}\n";
3278 print "No alias for $k\n";
3280 } ## end for my $k (@keys)
3284 =head4 C<source> - read commands from a file.
3286 Opens a lexical filehandle and stacks it on C<@cmdfhs>; C<DB::readline> will
3291 # source - read commands from a file (or pipe!) and execute.
3292 $cmd =~ /^source\s+(.*\S)/ && do {
3293 if ( open my $fh, $1 ) {
3295 # Opened OK; stick it in the list of file handles.
3301 &warn("Can't execute '$1': $!\n");
3306 $cmd =~ /^(enable|disable)\s+(\S+)\s*$/ && do {
3307 my ($cmd, $position) = ($1, $2);
3309 my ($fn, $line_num);
3310 if ($position =~ m{\A\d+\z})
3313 $line_num = $position;
3315 elsif ($position =~ m{\A(.*):(\d+)\z})
3317 ($fn, $line_num) = ($1, $2);
3321 &warn("Wrong spec for enable/disable argument.\n");
3325 if (_has_breakpoint_data_ref($fn, $line_num)) {
3326 _set_breakpoint_enabled_status($fn, $line_num,
3327 ($cmd eq 'enable' ? 1 : '')
3331 &warn("No breakpoint set at ${fn}:${line_num}\n");
3338 =head4 C<save> - send current history to a file
3340 Takes the complete history, (not the shrunken version you see with C<H>),
3341 and saves it to the given filename, so it can be replayed using C<source>.
3343 Note that all C<^(save|source)>'s are commented out with a view to minimise recursion.
3347 # save source - write commands to a file for later use
3348 $cmd =~ /^save\s*(.*)$/ && do {
3349 my $file = $1 || '.perl5dbrc'; # default?
3350 if ( open my $fh, "> $file" ) {
3352 # chomp to remove extraneous newlines from source'd files
3353 chomp( my @truelist =
3354 map { m/^\s*(save|source)/ ? "#$_" : $_ }
3356 print $fh join( "\n", @truelist );
3357 print "commands saved in $file\n";
3360 &warn("Can't save debugger commands in '$1': $!\n");
3365 =head4 C<R> - restart
3367 Restart the debugger session.
3369 =head4 C<rerun> - rerun the current session
3371 Return to any given position in the B<true>-history list
3375 # R - restart execution.
3376 # rerun - controlled restart execution.
3377 $cmd =~ /^(R|rerun\s*(.*))$/ && do {
3378 my @args = ($1 eq 'R' ? restart() : rerun($2));
3380 # Close all non-system fds for a clean restart. A more
3381 # correct method would be to close all fds that were not
3382 # open when the process started, but this seems to be
3383 # hard. See "debugger 'R'estart and open database
3384 # connections" on p5p.
3386 my $max_fd = 1024; # default if POSIX can't be loaded
3387 if (eval { require POSIX }) {
3388 eval { $max_fd = POSIX::sysconf(POSIX::_SC_OPEN_MAX()) };
3391 if (defined $max_fd) {
3392 foreach ($^F+1 .. $max_fd-1) {
3393 next unless open FD_TO_CLOSE, "<&=$_";
3398 # And run Perl again. We use exec() to keep the
3399 # PID stable (and that way $ini_pids is still valid).
3400 exec(@args) || print $OUT "exec failed: $!\n";
3405 =head4 C<|, ||> - pipe output through the pager.
3407 For C<|>, we save C<OUT> (the debugger's output filehandle) and C<STDOUT>
3408 (the program's standard output). For C<||>, we only save C<OUT>. We open a
3409 pipe to the pager (restoring the output filehandles if this fails). If this
3410 is the C<|> command, we also set up a C<SIGPIPE> handler which will simply
3411 set C<$signal>, sending us back into the debugger.
3413 We then trim off the pipe symbols and C<redo> the command loop at the
3414 C<PIPE> label, causing us to evaluate the command in C<$cmd> without
3419 # || - run command in the pager, with output to DB::OUT.
3420 $cmd =~ /^\|\|?\s*[^|]/ && do {
3421 if ( $pager =~ /^\|/ ) {
3423 # Default pager is into a pipe. Redirect I/O.
3424 open( SAVEOUT, ">&STDOUT" )
3425 || &warn("Can't save STDOUT");
3426 open( STDOUT, ">&OUT" )
3427 || &warn("Can't redirect STDOUT");
3428 } ## end if ($pager =~ /^\|/)
3431 # Not into a pipe. STDOUT is safe.
3432 open( SAVEOUT, ">&OUT" ) || &warn("Can't save DB::OUT");
3435 # Fix up environment to record we have less if so.
3438 unless ( $piped = open( OUT, $pager ) ) {
3440 # Couldn't open pipe to pager.
3441 &warn("Can't pipe output to '$pager'");
3442 if ( $pager =~ /^\|/ ) {
3444 # Redirect I/O back again.
3445 open( OUT, ">&STDOUT" ) # XXX: lost message
3446 || &warn("Can't restore DB::OUT");
3447 open( STDOUT, ">&SAVEOUT" )
3448 || &warn("Can't restore STDOUT");
3450 } ## end if ($pager =~ /^\|/)
3453 # Redirect I/O. STDOUT already safe.
3454 open( OUT, ">&STDOUT" ) # XXX: lost message
3455 || &warn("Can't restore DB::OUT");
3458 } ## end unless ($piped = open(OUT,...
3460 # Set up broken-pipe handler if necessary.
3461 $SIG{PIPE} = \&DB::catch
3463 && ( "" eq $SIG{PIPE} || "DEFAULT" eq $SIG{PIPE} );
3465 # Save current filehandle, unbuffer out, and put it back.
3466 $selected = select(OUT);
3469 # Don't put it back if pager was a pipe.
3470 select($selected), $selected = "" unless $cmd =~ /^\|\|/;
3472 # Trim off the pipe symbols and run the command now.
3473 $cmd =~ s/^\|+\s*//;
3477 =head3 END OF COMMAND PARSING
3479 Anything left in C<$cmd> at this point is a Perl expression that we want to
3480 evaluate. We'll always evaluate in the user's context, and fully qualify
3481 any variables we might want to address in the C<DB> package.
3485 # t - turn trace on.
3486 $cmd =~ s/^t\s+(\d+)?/\$DB::trace |= 1;\n/ && do {
3487 $trace_to_depth = $1 ? $stack_depth||0 + $1 : 1E9;
3490 # s - single-step. Remember the last command was 's'.
3491 $cmd =~ s/^s\s/\$DB::single = 1;\n/ && do { $laststep = 's' };
3493 # n - single-step, but not into subs. Remember last command
3495 $cmd =~ s/^n\s/\$DB::single = 2;\n/ && do { $laststep = 'n' };
3499 # Make sure the flag that says "the debugger's running" is
3500 # still on, to make sure we get control again.
3501 $evalarg = "\$^D = \$^D | \$DB::db_stop;\n$cmd";
3503 # Run *our* eval that executes in the caller's context.
3506 # Turn off the one-time-dump stuff now.
3508 $onetimeDump = undef;
3509 $onetimedumpDepth = undef;
3511 elsif ( $term_pid == $$ ) {
3512 eval { # May run under miniperl, when not available...
3517 # XXX If this is the master pid, print a newline.
3520 } ## end while (($term || &setterm...
3522 =head3 POST-COMMAND PROCESSING
3524 After each command, we check to see if the command output was piped anywhere.
3525 If so, we go through the necessary code to unhook the pipe and go back to
3526 our standard filehandles for input and output.
3532 # At the end of every command:
3535 # Unhook the pipe mechanism now.
3536 if ( $pager =~ /^\|/ ) {
3538 # No error from the child.
3541 # we cannot warn here: the handle is missing --tchrist
3542 close(OUT) || print SAVEOUT "\nCan't close DB::OUT\n";
3544 # most of the $? crud was coping with broken cshisms
3545 # $? is explicitly set to 0, so this never runs.
3547 print SAVEOUT "Pager '$pager' failed: ";
3549 print SAVEOUT "shell returned -1\n";
3552 print SAVEOUT ( $? & 127 )
3553 ? " (SIG#" . ( $? & 127 ) . ")"
3554 : "", ( $? & 128 ) ? " -- core dumped" : "", "\n";
3557 print SAVEOUT "status ", ( $? >> 8 ), "\n";
3561 # Reopen filehandle for our output (if we can) and
3562 # restore STDOUT (if we can).
3563 open( OUT, ">&STDOUT" ) || &warn("Can't restore DB::OUT");
3564 open( STDOUT, ">&SAVEOUT" )
3565 || &warn("Can't restore STDOUT");
3567 # Turn off pipe exception handler if necessary.
3568 $SIG{PIPE} = "DEFAULT" if $SIG{PIPE} eq \&DB::catch;
3570 # Will stop ignoring SIGPIPE if done like nohup(1)
3571 # does SIGINT but Perl doesn't give us a choice.
3572 } ## end if ($pager =~ /^\|/)
3575 # Non-piped "pager". Just restore STDOUT.
3576 open( OUT, ">&SAVEOUT" ) || &warn("Can't restore DB::OUT");
3579 # Close filehandle pager was using, restore the normal one
3582 select($selected), $selected = "" unless $selected eq "";
3586 } ## end if ($piped)
3589 =head3 COMMAND LOOP TERMINATION
3591 When commands have finished executing, we come here. If the user closed the
3592 input filehandle, we turn on C<$fall_off_end> to emulate a C<q> command. We
3593 evaluate any post-prompt items. We restore C<$@>, C<$!>, C<$^E>, C<$,>, C<$/>,
3594 C<$\>, and C<$^W>, and return a null list as expected by the Perl interpreter.
3595 The interpreter will then execute the next line and then return control to us
3600 # No more commands? Quit.
3601 $fall_off_end = 1 unless defined $cmd; # Emulate 'q' on EOF
3603 # Evaluate post-prompt commands.
3604 foreach $evalarg (@$post) {
3607 } # if ($single || $signal)
3609 # Put the user's globals back where you found them.
3610 ( $@, $!, $^E, $,, $/, $\, $^W ) = @saved;
3614 # The following code may be executed now:
3619 C<sub> is called whenever a subroutine call happens in the program being
3620 debugged. The variable C<$DB::sub> contains the name of the subroutine
3623 The core function of this subroutine is to actually call the sub in the proper
3624 context, capturing its output. This of course causes C<DB::DB> to get called
3625 again, repeating until the subroutine ends and returns control to C<DB::sub>
3626 again. Once control returns, C<DB::sub> figures out whether or not to dump the
3627 return value, and returns its captured copy of the return value as its own
3628 return value. The value then feeds back into the program being debugged as if
3629 C<DB::sub> hadn't been there at all.
3631 C<sub> does all the work of printing the subroutine entry and exit messages
3632 enabled by setting C<$frame>. It notes what sub the autoloader got called for,
3633 and also prints the return value if needed (for the C<r> command and if
3634 the 16 bit is set in C<$frame>).
3636 It also tracks the subroutine call depth by saving the current setting of
3637 C<$single> in the C<@stack> package global; if this exceeds the value in
3638 C<$deep>, C<sub> automatically turns on printing of the current depth by
3639 setting the C<4> bit in C<$single>. In any case, it keeps the current setting
3640 of stop/don't stop on entry to subs set as it currently is set.
3642 =head3 C<caller()> support
3644 If C<caller()> is called from the package C<DB>, it provides some
3645 additional data, in the following order:
3651 The package name the sub was in
3653 =item * C<$filename>
3655 The filename it was defined in
3659 The line number it was defined on
3661 =item * C<$subroutine>
3663 The subroutine name; C<(eval)> if an C<eval>().
3667 1 if it has arguments, 0 if not
3669 =item * C<$wantarray>
3671 1 if array context, 0 if scalar context
3673 =item * C<$evaltext>
3675 The C<eval>() text, if any (undefined for C<eval BLOCK>)
3677 =item * C<$is_require>
3679 frame was created by a C<use> or C<require> statement
3683 pragma information; subject to change between versions
3687 pragma information; subject to change between versions
3689 =item * C<@DB::args>
3691 arguments with which the subroutine was invoked
3698 # Do not use a regex in this subroutine -> results in corrupted memory
3699 # See: [perl #66110]
3701 # lock ourselves under threads
3704 # Whether or not the autoloader was running, a scalar to put the
3705 # sub's return value in (if needed), and an array to put the sub's
3706 # return value in (if needed).
3707 my ( $al, $ret, @ret ) = "";
3708 if ($sub eq 'threads::new' && $ENV{PERL5DB_THREADED}) {
3709 print "creating new thread\n";
3712 # If the last ten characters are '::AUTOLOAD', note we've traced
3713 # into AUTOLOAD for $sub.
3714 if ( length($sub) > 10 && substr( $sub, -10, 10 ) eq '::AUTOLOAD' ) {
3715 $al = " for $$sub" if defined $$sub;
3718 # We stack the stack pointer and then increment it to protect us
3719 # from a situation that might unwind a whole bunch of call frames
3720 # at once. Localizing the stack pointer means that it will automatically
3721 # unwind the same amount when multiple stack frames are unwound.
3722 local $stack_depth = $stack_depth + 1; # Protect from non-local exits
3725 $#stack = $stack_depth;
3727 # Save current single-step setting.
3728 $stack[-1] = $single;
3730 # Turn off all flags except single-stepping.
3733 # If we've gotten really deeply recursed, turn on the flag that will
3734 # make us stop with the 'deep recursion' message.
3735 $single |= 4 if $stack_depth == $deep;
3737 # If frame messages are on ...
3739 $frame & 4 # Extended frame entry message
3741 print_lineinfo( ' ' x ( $stack_depth - 1 ), "in " ),
3743 # Why -1? But it works! :-(
3744 # Because print_trace will call add 1 to it and then call
3745 # dump_trace; this results in our skipping -1+1 = 0 stack frames
3747 print_trace( $LINEINFO, -1, 1, 1, "$sub$al" )
3749 : print_lineinfo( ' ' x ( $stack_depth - 1 ), "entering $sub$al\n" )
3751 # standard frame entry message
3755 # Determine the sub's return type, and capture appropriately.
3758 # Called in array context. call sub and capture output.
3759 # DB::DB will recursively get control again if appropriate; we'll come
3760 # back here when the sub is finished.
3763 # Pop the single-step value back off the stack.
3764 $single |= $stack[ $stack_depth-- ];
3766 # Check for exit trace messages...
3768 $frame & 4 # Extended exit message
3770 print_lineinfo( ' ' x $stack_depth, "out " ),
3771 print_trace( $LINEINFO, -1, 1, 1, "$sub$al" )
3773 : print_lineinfo( ' ' x $stack_depth, "exited $sub$al\n" )
3775 # Standard exit message
3779 # Print the return info if we need to.
3780 if ( $doret eq $stack_depth or $frame & 16 ) {
3782 # Turn off output record separator.
3784 my $fh = ( $doret eq $stack_depth ? $OUT : $LINEINFO );
3786 # Indent if we're printing because of $frame tracing.
3787 print $fh ' ' x $stack_depth if $frame & 16;
3789 # Print the return value.
3790 print $fh "list context return from $sub:\n";
3791 dumpit( $fh, \@ret );
3793 # And don't print it again.
3795 } ## end if ($doret eq $stack_depth...
3796 # And we have to return the return value now.
3798 } ## end if (wantarray)
3802 if ( defined wantarray ) {
3804 # Save the value if it's wanted at all.
3809 # Void return, explicitly.
3814 # Pop the single-step value off the stack.
3815 $single |= $stack[ $stack_depth-- ];
3817 # If we're doing exit messages...
3819 $frame & 4 # Extended messages
3821 print_lineinfo( ' ' x $stack_depth, "out " ),
3822 print_trace( $LINEINFO, -1, 1, 1, "$sub$al" )
3824 : print_lineinfo( ' ' x $stack_depth, "exited $sub$al\n" )
3830 # If we are supposed to show the return value... same as before.
3831 if ( $doret eq $stack_depth or $frame & 16 and defined wantarray ) {
3833 my $fh = ( $doret eq $stack_depth ? $OUT : $LINEINFO );
3834 print $fh ( ' ' x $stack_depth ) if $frame & 16;
3837 ? "scalar context return from $sub: "
3838 : "void context return from $sub\n"
3840 dumpit( $fh, $ret ) if defined wantarray;
3842 } ## end if ($doret eq $stack_depth...
3844 # Return the appropriate scalar value.
3846 } ## end else [ if (wantarray)
3851 # lock ourselves under threads
3854 # Whether or not the autoloader was running, a scalar to put the
3855 # sub's return value in (if needed), and an array to put the sub's
3856 # return value in (if needed).
3857 my ( $al, $ret, @ret ) = "";
3858 if ($sub =~ /^threads::new$/ && $ENV{PERL5DB_THREADED}) {
3859 print "creating new thread\n";
3862 # If the last ten characters are C'::AUTOLOAD', note we've traced
3863 # into AUTOLOAD for $sub.
3864 if ( length($sub) > 10 && substr( $sub, -10, 10 ) eq '::AUTOLOAD' ) {
3868 # We stack the stack pointer and then increment it to protect us
3869 # from a situation that might unwind a whole bunch of call frames
3870 # at once. Localizing the stack pointer means that it will automatically
3871 # unwind the same amount when multiple stack frames are unwound.
3872 local $stack_depth = $stack_depth + 1; # Protect from non-local exits
3875 $#stack = $stack_depth;
3877 # Save current single-step setting.
3878 $stack[-1] = $single;
3880 # Turn off all flags except single-stepping.
3883 # If we've gotten really deeply recursed, turn on the flag that will
3884 # make us stop with the 'deep recursion' message.
3885 $single |= 4 if $stack_depth == $deep;
3887 # If frame messages are on ...
3889 $frame & 4 # Extended frame entry message
3891 print_lineinfo( ' ' x ( $stack_depth - 1 ), "in " ),
3893 # Why -1? But it works! :-(
3894 # Because print_trace will call add 1 to it and then call
3895 # dump_trace; this results in our skipping -1+1 = 0 stack frames
3897 print_trace( $LINEINFO, -1, 1, 1, "$sub$al" )
3899 : print_lineinfo( ' ' x ( $stack_depth - 1 ), "entering $sub$al\n" )
3901 # standard frame entry message
3905 # Pop the single-step value back off the stack.
3906 $single |= $stack[ $stack_depth-- ];
3908 # call the original lvalue sub.
3912 # Abstracting common code from multiple places elsewhere:
3913 sub depth_print_lineinfo {
3914 my $always_print = shift;
3916 print_lineinfo( @_ ) if ($always_print or $stack_depth < $trace_to_depth);
3919 =head1 EXTENDED COMMAND HANDLING AND THE COMMAND API
3921 In Perl 5.8.0, there was a major realignment of the commands and what they did,
3922 Most of the changes were to systematize the command structure and to eliminate
3923 commands that threw away user input without checking.
3925 The following sections describe the code added to make it easy to support
3926 multiple command sets with conflicting command names. This section is a start
3927 at unifying all command processing to make it simpler to develop commands.
3929 Note that all the cmd_[a-zA-Z] subroutines require the command name, a line
3930 number, and C<$dbline> (the current line) as arguments.
3932 Support functions in this section which have multiple modes of failure C<die>
3933 on error; the rest simply return a false value.
3935 The user-interface functions (all of the C<cmd_*> functions) just output
3940 The C<%set> hash defines the mapping from command letter to subroutine
3943 C<%set> is a two-level hash, indexed by set name and then by command name.
3944 Note that trying to set the CommandSet to C<foobar> simply results in the
3945 5.8.0 command set being used, since there's no top-level entry for C<foobar>.
3954 'A' => 'pre580_null',
3956 'B' => 'pre580_null',
3957 'd' => 'pre580_null',
3960 'M' => 'pre580_null',
3962 'o' => 'pre580_null',
3968 '<' => 'pre590_prepost',
3969 '<<' => 'pre590_prepost',
3970 '>' => 'pre590_prepost',
3971 '>>' => 'pre590_prepost',
3972 '{' => 'pre590_prepost',
3973 '{{' => 'pre590_prepost',
3977 my %breakpoints_data;
3979 sub _has_breakpoint_data_ref {
3980 my ($filename, $line) = @_;
3983 exists( $breakpoints_data{$filename} )
3985 exists( $breakpoints_data{$filename}{$line} )
3989 sub _get_breakpoint_data_ref {
3990 my ($filename, $line) = @_;
3992 return ($breakpoints_data{$filename}{$line} ||= +{});
3995 sub _delete_breakpoint_data_ref {
3996 my ($filename, $line) = @_;
3998 delete($breakpoints_data{$filename}{$line});
3999 if (! scalar(keys( %{$breakpoints_data{$filename}} )) ) {
4000 delete($breakpoints_data{$filename});
4006 sub _set_breakpoint_enabled_status {
4007 my ($filename, $line, $status) = @_;
4009 _get_breakpoint_data_ref($filename, $line)->{'enabled'} =
4016 sub _enable_breakpoint_temp_enabled_status {
4017 my ($filename, $line) = @_;
4019 _get_breakpoint_data_ref($filename, $line)->{'temp_enabled'} = 1;
4024 sub _cancel_breakpoint_temp_enabled_status {
4025 my ($filename, $line) = @_;
4027 my $ref = _get_breakpoint_data_ref($filename, $line);
4029 delete ($ref->{'temp_enabled'});
4032 _delete_breakpoint_data_ref($filename, $line);
4038 sub _is_breakpoint_enabled {
4039 my ($filename, $line) = @_;
4041 my $data_ref = _get_breakpoint_data_ref($filename, $line);
4042 return ($data_ref->{'enabled'} || $data_ref->{'temp_enabled'});
4045 =head2 C<cmd_wrapper()> (API)
4047 C<cmd_wrapper()> allows the debugger to switch command sets
4048 depending on the value of the C<CommandSet> option.
4050 It tries to look up the command in the C<%set> package-level I<lexical>
4051 (which means external entities can't fiddle with it) and create the name of
4052 the sub to call based on the value found in the hash (if it's there). I<All>
4053 of the commands to be handled in a set have to be added to C<%set>; if they
4054 aren't found, the 5.8.0 equivalent is called (if there is one).
4056 This code uses symbolic references.
4063 my $dblineno = shift;
4065 # Assemble the command subroutine's name by looking up the
4066 # command set and command name in %set. If we can't find it,
4067 # default to the older version of the command.
4069 . ( $set{$CommandSet}{$cmd}
4070 || ( $cmd =~ /^[<>{]+/o ? 'prepost' : $cmd ) );
4072 # Call the command subroutine, call it by name.
4073 return &$call( $cmd, $line, $dblineno );
4074 } ## end sub cmd_wrapper
4076 =head3 C<cmd_a> (command)
4078 The C<a> command handles pre-execution actions. These are associated with a
4079 particular line, so they're stored in C<%dbline>. We default to the current
4080 line if none is specified.
4086 my $line = shift || ''; # [.|line] expr
4089 # If it's dot (here), or not all digits, use the current line.
4090 $line =~ s/^(\.|(?:[^\d]))/$dbline/;
4092 # Should be a line number followed by an expression.
4093 if ( $line =~ /^\s*(\d*)\s*(\S.+)/ ) {
4094 my ( $lineno, $expr ) = ( $1, $2 );
4096 # If we have an expression ...
4097 if ( length $expr ) {
4099 # ... but the line isn't breakable, complain.
4100 if ( $dbline[$lineno] == 0 ) {
4102 "Line $lineno($dbline[$lineno]) does not have an action?\n";
4106 # It's executable. Record that the line has an action.
4107 $had_breakpoints{$filename} |= 2;
4109 # Remove any action, temp breakpoint, etc.
4110 $dbline{$lineno} =~ s/\0[^\0]*//;
4112 # Add the action to the line.
4113 $dbline{$lineno} .= "\0" . action($expr);
4115 } ## end if (length $expr)
4116 } ## end if ($line =~ /^\s*(\d*)\s*(\S.+)/)
4121 "Adding an action requires an optional lineno and an expression\n"
4126 =head3 C<cmd_A> (command)
4128 Delete actions. Similar to above, except the delete code is in a separate
4129 subroutine, C<delete_action>.
4135 my $line = shift || '';
4139 $line =~ s/^\./$dbline/;
4141 # Call delete_action with a null param to delete them all.
4142 # The '1' forces the eval to be true. It'll be false only
4143 # if delete_action blows up for some reason, in which case
4144 # we print $@ and get out.
4145 if ( $line eq '*' ) {
4146 eval { &delete_action(); 1 } or print $OUT $@ and return;
4149 # There's a real line number. Pass it to delete_action.
4150 # Error trapping is as above.
4151 elsif ( $line =~ /^(\S.*)/ ) {
4152 eval { &delete_action($1); 1 } or print $OUT $@ and return;
4155 # Swing and a miss. Bad syntax.
4158 "Deleting an action requires a line number, or '*' for all\n" ; # hint
4162 =head3 C<delete_action> (API)
4164 C<delete_action> accepts either a line number or C<undef>. If a line number
4165 is specified, we check for the line being executable (if it's not, it
4166 couldn't have had an action). If it is, we just take the action off (this
4167 will get any kind of an action, including breakpoints).
4173 if ( defined($i) ) {
4176 die "Line $i has no action .\n" if $dbline[$i] == 0;
4178 # Nuke whatever's there.
4179 $dbline{$i} =~ s/\0[^\0]*//; # \^a
4180 delete $dbline{$i} if $dbline{$i} eq '';
4183 print $OUT "Deleting all actions...\n";
4184 for my $file ( keys %had_breakpoints ) {
4185 local *dbline = $main::{ '_<' . $file };
4188 for ( $i = 1 ; $i <= $max ; $i++ ) {
4189 if ( defined $dbline{$i} ) {
4190 $dbline{$i} =~ s/\0[^\0]*//;
4191 delete $dbline{$i} if $dbline{$i} eq '';
4193 unless ( $had_breakpoints{$file} &= ~2 ) {
4194 delete $had_breakpoints{$file};
4196 } ## end for ($i = 1 ; $i <= $max...
4197 } ## end for my $file (keys %had_breakpoints)
4198 } ## end else [ if (defined($i))
4199 } ## end sub delete_action
4201 =head3 C<cmd_b> (command)
4203 Set breakpoints. Since breakpoints can be set in so many places, in so many
4204 ways, conditionally or not, the breakpoint code is kind of complex. Mostly,
4205 we try to parse the command type, and then shuttle it off to an appropriate
4206 subroutine to actually do the work of setting the breakpoint in the right
4213 my $line = shift; # [.|line] [cond]
4216 # Make . the current line number if it's there..
4217 $line =~ s/^\.(\s|\z)/$dbline$1/;
4219 # No line number, no condition. Simple break on current line.
4220 if ( $line =~ /^\s*$/ ) {
4221 &cmd_b_line( $dbline, 1 );
4224 # Break on load for a file.
4225 elsif ( $line =~ /^load\b\s*(.*)/ ) {
4231 # b compile|postpone <some sub> [<condition>]
4232 # The interpreter actually traps this one for us; we just put the
4233 # necessary condition in the %postponed hash.
4234 elsif ( $line =~ /^(postpone|compile)\b\s*([':A-Za-z_][':\w]*)\s*(.*)/ ) {
4236 # Capture the condition if there is one. Make it true if none.
4237 my $cond = length $3 ? $3 : '1';
4239 # Save the sub name and set $break to 1 if $1 was 'postpone', 0
4240 # if it was 'compile'.
4241 my ( $subname, $break ) = ( $2, $1 eq 'postpone' );
4243 # De-Perl4-ify the name - ' separators to ::.
4244 $subname =~ s/\'/::/g;
4246 # Qualify it into the current package unless it's already qualified.
4247 $subname = "${'package'}::" . $subname unless $subname =~ /::/;
4249 # Add main if it starts with ::.
4250 $subname = "main" . $subname if substr( $subname, 0, 2 ) eq "::";
4252 # Save the break type for this sub.
4253 $postponed{$subname} = $break ? "break +0 if $cond" : "compile";
4254 } ## end elsif ($line =~ ...
4255 # b <filename>:<line> [<condition>]
4256 elsif ($line =~ /\A(\S+[^:]):(\d+)\s*(.*)/ms) {
4257 my ($filename, $line_num, $cond) = ($1, $2, $3);
4258 cmd_b_filename_line(
4261 (length($cond) ? $cond : '1'),
4264 # b <sub name> [<condition>]
4265 elsif ( $line =~ /^([':A-Za-z_][':\w]*(?:\[.*\])?)\s*(.*)/ ) {
4269 $cond = length $2 ? $2 : '1';
4270 &cmd_b_sub( $subname, $cond );
4273 # b <line> [<condition>].
4274 elsif ( $line =~ /^(\d*)\s*(.*)/ ) {
4276 # Capture the line. If none, it's the current line.
4277 $line = $1 || $dbline;
4279 # If there's no condition, make it '1'.
4280 $cond = length $2 ? $2 : '1';
4283 &cmd_b_line( $line, $cond );
4286 # Line didn't make sense.
4288 print "confused by line($line)?\n";
4292 =head3 C<break_on_load> (API)
4294 We want to break when this file is loaded. Mark this file in the
4295 C<%break_on_load> hash, and note that it has a breakpoint in
4296 C<%had_breakpoints>.
4302 $break_on_load{$file} = 1;
4303 $had_breakpoints{$file} |= 1;
4306 =head3 C<report_break_on_load> (API)
4308 Gives us an array of filenames that are set to break on load. Note that
4309 only files with break-on-load are in here, so simply showing the keys
4314 sub report_break_on_load {
4315 sort keys %break_on_load;
4318 =head3 C<cmd_b_load> (command)
4320 We take the file passed in and try to find it in C<%INC> (which maps modules
4321 to files they came from). We mark those files for break-on-load via
4322 C<break_on_load> and then report that it was done.
4330 # This is a block because that way we can use a redo inside it
4331 # even without there being any looping structure at all outside it.
4334 # Save short name and full path if found.
4336 push @files, $::INC{$file} if $::INC{$file};
4338 # Tack on .pm and do it again unless there was a '.' in the name
4340 $file .= '.pm', redo unless $file =~ /\./;
4343 # Do the real work here.
4344 break_on_load($_) for @files;
4346 # All the files that have break-on-load breakpoints.
4347 @files = report_break_on_load;
4349 # Normalize for the purposes of our printing this.
4352 print $OUT "Will stop on load of '@files'.\n";
4353 } ## end sub cmd_b_load
4355 =head3 C<$filename_error> (API package global)
4357 Several of the functions we need to implement in the API need to work both
4358 on the current file and on other files. We don't want to duplicate code, so
4359 C<$filename_error> is used to contain the name of the file that's being
4360 worked on (if it's not the current one).
4362 We can now build functions in pairs: the basic function works on the current
4363 file, and uses C<$filename_error> as part of its error message. Since this is
4364 initialized to C<"">, no filename will appear when we are working on the
4367 The second function is a wrapper which does the following:
4373 Localizes C<$filename_error> and sets it to the name of the file to be processed.
4377 Localizes the C<*dbline> glob and reassigns it to point to the file we want to process.
4381 Calls the first function.
4383 The first function works on the I<current> file (i.e., the one we changed to),
4384 and prints C<$filename_error> in the error message (the name of the other file)
4385 if it needs to. When the functions return, C<*dbline> is restored to point
4386 to the actual current file (the one we're executing in) and
4387 C<$filename_error> is restored to C<"">. This restores everything to
4388 the way it was before the second function was called at all.
4390 See the comments in C<breakable_line> and C<breakable_line_in_file> for more
4397 $filename_error = '';
4399 =head3 breakable_line(from, to) (API)
4401 The subroutine decides whether or not a line in the current file is breakable.
4402 It walks through C<@dbline> within the range of lines specified, looking for
4403 the first line that is breakable.
4405 If C<$to> is greater than C<$from>, the search moves forwards, finding the
4406 first line I<after> C<$to> that's breakable, if there is one.
4408 If C<$from> is greater than C<$to>, the search goes I<backwards>, finding the
4409 first line I<before> C<$to> that's breakable, if there is one.
4413 sub breakable_line {
4415 my ( $from, $to ) = @_;
4417 # $i is the start point. (Where are the FORTRAN programs of yesteryear?)
4420 # If there are at least 2 arguments, we're trying to search a range.
4423 # $delta is positive for a forward search, negative for a backward one.
4424 my $delta = $from < $to ? +1 : -1;
4426 # Keep us from running off the ends of the file.
4427 my $limit = $delta > 0 ? $#dbline : 1;
4429 # Clever test. If you're a mathematician, it's obvious why this
4430 # test works. If not:
4431 # If $delta is positive (going forward), $limit will be $#dbline.
4432 # If $to is less than $limit, ($limit - $to) will be positive, times
4433 # $delta of 1 (positive), so the result is > 0 and we should use $to
4434 # as the stopping point.
4436 # If $to is greater than $limit, ($limit - $to) is negative,
4437 # times $delta of 1 (positive), so the result is < 0 and we should
4438 # use $limit ($#dbline) as the stopping point.
4440 # If $delta is negative (going backward), $limit will be 1.
4441 # If $to is zero, ($limit - $to) will be 1, times $delta of -1
4442 # (negative) so the result is > 0, and we use $to as the stopping
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