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2=head1 NAME
3
4C<perl5db.pl> - the perl debugger
5
6=head1 SYNOPSIS
7
8 perl -d your_Perl_script
9
10=head1 DESCRIPTION
11
12C<perl5db.pl> is the perl debugger. It is loaded automatically by Perl when
13you invoke a script with C<perl -d>. This documentation tries to outline the
14structure and services provided by C<perl5db.pl>, and to describe how you
15can use them.
16
17=head1 GENERAL NOTES
18
19The debugger can look pretty forbidding to many Perl programmers. There are
20a number of reasons for this, many stemming out of the debugger's history.
21
22When the debugger was first written, Perl didn't have a lot of its nicer
23features - no references, no lexical variables, no closures, no object-oriented
24programming. So a lot of the things one would normally have done using such
25features was done using global variables, globs and the C<local()> operator
26in creative ways.
27
28Some of these have survived into the current debugger; a few of the more
29interesting and still-useful idioms are noted in this section, along with notes
30on the comments themselves.
31
32=head2 Why not use more lexicals?
33
34Experienced Perl programmers will note that the debugger code tends to use
35mostly package globals rather than lexically-scoped variables. This is done
36to allow a significant amount of control of the debugger from outside the
37debugger itself.
38
39Unfortunately, though the variables are accessible, they're not well
40documented, so it's generally been a decision that hasn't made a lot of
41difference to most users. Where appropriate, comments have been added to
42make variables more accessible and usable, with the understanding that these
43i<are> debugger internals, and are therefore subject to change. Future
44development should probably attempt to replace the globals with a well-defined
45API, but for now, the variables are what we've got.
46
47=head2 Automated variable stacking via C<local()>
48
49As you may recall from reading C<perlfunc>, the C<local()> operator makes a
50temporary copy of a variable in the current scope. When the scope ends, the
51old copy is restored. This is often used in the debugger to handle the
52automatic stacking of variables during recursive calls:
53
54 sub foo {
55 local $some_global++;
56
57 # Do some stuff, then ...
58 return;
59 }
60
61What happens is that on entry to the subroutine, C<$some_global> is localized,
62then altered. When the subroutine returns, Perl automatically undoes the
63localization, restoring the previous value. Voila, automatic stack management.
64
65The debugger uses this trick a I<lot>. Of particular note is C<DB::eval>,
66which lets the debugger get control inside of C<eval>'ed code. The debugger
67localizes a saved copy of C<$@> inside the subroutine, which allows it to
68keep C<$@> safe until it C<DB::eval> returns, at which point the previous
69value of C<$@> is restored. This makes it simple (well, I<simpler>) to keep
70track of C<$@> inside C<eval>s which C<eval> other C<eval's>.
71
72In any case, watch for this pattern. It occurs fairly often.
73
74=head2 The C<^> trick
75
76This is used to cleverly reverse the sense of a logical test depending on
77the value of an auxiliary variable. For instance, the debugger's C<S>
78(search for subroutines by pattern) allows you to negate the pattern
79like this:
80
81 # Find all non-'foo' subs:
82 S !/foo/
83
84Boolean algebra states that the truth table for XOR looks like this:
85
86=over 4
87
88=item * 0 ^ 0 = 0
89
90(! not present and no match) --> false, don't print
91
92=item * 0 ^ 1 = 1
93
94(! not present and matches) --> true, print
95
96=item * 1 ^ 0 = 1
97
98(! present and no match) --> true, print
99
100=item * 1 ^ 1 = 0
101
102(! present and matches) --> false, don't print
103
104=back
105
106As you can see, the first pair applies when C<!> isn't supplied, and
107the second pair applies when it isn't. The XOR simply allows us to
108compact a more complicated if-then-elseif-else into a more elegant
109(but perhaps overly clever) single test. After all, it needed this
110explanation...
111
112=head2 FLAGS, FLAGS, FLAGS
113
114There is a certain C programming legacy in the debugger. Some variables,
115such as C<$single>, C<$trace>, and C<$frame>, have "magical" values composed
116of 1, 2, 4, etc. (powers of 2) OR'ed together. This allows several pieces
117of state to be stored independently in a single scalar.
118
119A test like
120
121 if ($scalar & 4) ...
122
123is checking to see if the appropriate bit is on. Since each bit can be
124"addressed" independently in this way, C<$scalar> is acting sort of like
125an array of bits. Obviously, since the contents of C<$scalar> are just a
126bit-pattern, we can save and restore it easily (it will just look like
127a number).
128
129The problem, is of course, that this tends to leave magic numbers scattered
130all over your program whenever a bit is set, cleared, or checked. So why do
131it?
132
133=over 4
134
135
136=item * First, doing an arithmetical or bitwise operation on a scalar is
137just about the fastest thing you can do in Perl: C<use constant> actually
138creates a subroutine call, and array hand hash lookups are much slower. Is
139this over-optimization at the expense of readability? Possibly, but the
140debugger accesses these variables a I<lot>. Any rewrite of the code will
141probably have to benchmark alternate implementations and see which is the
142best balance of readability and speed, and then document how it actually
143works.
144
145=item * Second, it's very easy to serialize a scalar number. This is done in
146the restart code; the debugger state variables are saved in C<%ENV> and then
147restored when the debugger is restarted. Having them be just numbers makes
148this trivial.
149
150=item * Third, some of these variables are being shared with the Perl core
151smack in the middle of the interpreter's execution loop. It's much faster for
152a C program (like the interpreter) to check a bit in a scalar than to access
153several different variables (or a Perl array).
154
155=back
156
157=head2 What are those C<XXX> comments for?
158
159Any comment containing C<XXX> means that the comment is either somewhat
160speculative - it's not exactly clear what a given variable or chunk of
161code is doing, or that it is incomplete - the basics may be clear, but the
162subtleties are not completely documented.
163
164Send in a patch if you can clear up, fill out, or clarify an C<XXX>.
165
166=head1 DATA STRUCTURES MAINTAINED BY CORE
167
168There are a number of special data structures provided to the debugger by
169the Perl interpreter.
170
171The array C<@{$main::{'_<'.$filename}}> (aliased locally to C<@dbline> via glob
172assignment) contains the text from C<$filename>, with each element
173corresponding to a single line of C<$filename>.
174
175The hash C<%{'_<'.$filename}> (aliased locally to C<%dbline> via glob
176assignment) contains breakpoints and actions. The keys are line numbers;
177you can set individual values, but not the whole hash. The Perl interpreter
178uses this hash to determine where breakpoints have been set. Any true value is
179considered to be a breakpoint; C<perl5db.pl> uses "$break_condition\0$action".
180Values are magical in numeric context: 1 if the line is breakable, 0 if not.
181
182The scalar ${'_<'.$filename} contains $filename XXX What?
183
184=head1 DEBUGGER STARTUP
185
186When C<perl5db.pl> starts, it reads an rcfile (C<perl5db.ini> for
187non-interactive sessions, C<.perldb> for interactive ones) that can set a number
188of options. In addition, this file may define a subroutine C<&afterinit>
189that will be executed (in the debugger's context) after the debugger has
190initialized itself.
191
192Next, it checks the C<PERLDB_OPTS> environment variable and treats its
193contents as the argument of a debugger <C<o> command.
194
195=head2 STARTUP-ONLY OPTIONS
196
197The following options can only be specified at startup.
198To set them in your rcfile, add a call to
199C<&parse_options("optionName=new_value")>.
200
201=over 4
202
203=item * TTY
204
205the TTY to use for debugging i/o.
206
207=item * noTTY
208
209if set, goes in NonStop mode. On interrupt, if TTY is not set,
210uses the value of noTTY or "/tmp/perldbtty$$" to find TTY using
211Term::Rendezvous. Current variant is to have the name of TTY in this
212file.
213
214=item * ReadLine
215
216If false, a dummy ReadLine is used, so you can debug
217ReadLine applications.
218
219=item * NonStop
220
221if true, no i/o is performed until interrupt.
222
223=item * LineInfo
224
225file or pipe to print line number info to. If it is a
226pipe, a short "emacs like" message is used.
227
228=item * RemotePort
229
230host:port to connect to on remote host for remote debugging.
231
232=back
233
234=head3 SAMPLE RCFILE
235
236 &parse_options("NonStop=1 LineInfo=db.out");
237 sub afterinit { $trace = 1; }
238
239The script will run without human intervention, putting trace
240information into C<db.out>. (If you interrupt it, you had better
241reset C<LineInfo> to something "interactive"!)
242
243=head1 INTERNALS DESCRIPTION
244
245=head2 DEBUGGER INTERFACE VARIABLES
246
247Perl supplies the values for C<%sub>. It effectively inserts
248a C<&DB'DB();> in front of each place that can have a
249breakpoint. At each subroutine call, it calls C<&DB::sub> with
250C<$DB::sub> set to the called subroutine. It also inserts a C<BEGIN
251{require 'perl5db.pl'}> before the first line.
252
253After each C<require>d file is compiled, but before it is executed, a
254call to C<&DB::postponed($main::{'_<'.$filename})> is done. C<$filename>
255is the expanded name of the C<require>d file (as found via C<%INC>).
256
257=head3 IMPORTANT INTERNAL VARIABLES
258
259=head4 C<$CreateTTY>
260
261Used to control when the debugger will attempt to acquire another TTY to be
262used for input.
263
264=over
265
266=item * 1 - on C<fork()>
267
268=item * 2 - debugger is started inside debugger
269
270=item * 4 - on startup
271
272=back
273
274=head4 C<$doret>
275
276The value -2 indicates that no return value should be printed.
277Any other positive value causes C<DB::sub> to print return values.
278
279=head4 C<$evalarg>
280
281The item to be eval'ed by C<DB::eval>. Used to prevent messing with the current
282contents of C<@_> when C<DB::eval> is called.
283
284=head4 C<$frame>
285
286Determines what messages (if any) will get printed when a subroutine (or eval)
287is entered or exited.
288
289=over 4
290
291=item * 0 - No enter/exit messages
292
293=item * 1 - Print "entering" messages on subroutine entry
294
295=item * 2 - Adds exit messages on subroutine exit. If no other flag is on, acts like 1+2.
296
297=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.
298
299=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.
300
301=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.
302
303=back
304
305To get everything, use C<$frame=30> (or C<o f-30> as a debugger command).
306The debugger internally juggles the value of C<$frame> during execution to
307protect external modules that the debugger uses from getting traced.
308
309=head4 C<$level>
310
311Tracks current debugger nesting level. Used to figure out how many
312C<E<lt>E<gt>> pairs to surround the line number with when the debugger
313outputs a prompt. Also used to help determine if the program has finished
314during command parsing.
315
316=head4 C<$onetimeDump>
317
318Controls what (if anything) C<DB::eval()> will print after evaluating an
319expression.
320
321=over 4
322
323=item * C<undef> - don't print anything
324
325=item * C<dump> - use C<dumpvar.pl> to display the value returned
326
327=item * C<methods> - print the methods callable on the first item returned
328
329=back
330
331=head4 C<$onetimeDumpDepth>
332
333Controls how far down C<dumpvar.pl> will go before printing '...' while
334dumping a structure. Numeric. If C<undef>, print all levels.
335
336=head4 C<$signal>
337
338Used to track whether or not an C<INT> signal has been detected. C<DB::DB()>,
339which is called before every statement, checks this and puts the user into
340command mode if it finds C<$signal> set to a true value.
341
342=head4 C<$single>
343
344Controls behavior during single-stepping. Stacked in C<@stack> on entry to
345each subroutine; popped again at the end of each subroutine.
346
347=over 4
348
349=item * 0 - run continuously.
350
351=item * 1 - single-step, go into subs. The 's' command.
352
353=item * 2 - single-step, don't go into subs. The 'n' command.
354
355=item * 4 - print current sub depth (turned on to force this when "too much
356recursion" occurs.
357
358=back
359
360=head4 C<$trace>
361
362Controls the output of trace information.
363
364=over 4
365
366=item * 1 - The C<t> command was entered to turn on tracing (every line executed is printed)
367
368=item * 2 - watch expressions are active
369
370=item * 4 - user defined a C<watchfunction()> in C<afterinit()>
371
372=back
373
374=head4 C<$slave_editor>
375
3761 if C<LINEINFO> was directed to a pipe; 0 otherwise.
377
378=head4 C<@cmdfhs>
379
380Stack of filehandles that C<DB::readline()> will read commands from.
381Manipulated by the debugger's C<source> command and C<DB::readline()> itself.
382
383=head4 C<@dbline>
384
385Local alias to the magical line array, C<@{$main::{'_<'.$filename}}> ,
386supplied by the Perl interpreter to the debugger. Contains the source.
387
388=head4 C<@old_watch>
389
390Previous values of watch expressions. First set when the expression is
391entered; reset whenever the watch expression changes.
392
393=head4 C<@saved>
394
395Saves important globals (C<$@>, C<$!>, C<$^E>, C<$,>, C<$/>, C<$\>, C<$^W>)
396so that the debugger can substitute safe values while it's running, and
397restore them when it returns control.
398
399=head4 C<@stack>
400
401Saves the current value of C<$single> on entry to a subroutine.
402Manipulated by the C<c> command to turn off tracing in all subs above the
403current one.
404
405=head4 C<@to_watch>
406
407The 'watch' expressions: to be evaluated before each line is executed.
408
409=head4 C<@typeahead>
410
411The typeahead buffer, used by C<DB::readline>.
412
413=head4 C<%alias>
414
415Command aliases. Stored as character strings to be substituted for a command
416entered.
417
418=head4 C<%break_on_load>
419
420Keys are file names, values are 1 (break when this file is loaded) or undef
421(don't break when it is loaded).
422
423=head4 C<%dbline>
424
425Keys are line numbers, values are "condition\0action". If used in numeric
426context, values are 0 if not breakable, 1 if breakable, no matter what is
427in the actual hash entry.
428
429=head4 C<%had_breakpoints>
430
431Keys are file names; values are bitfields:
432
433=over 4
434
435=item * 1 - file has a breakpoint in it.
436
437=item * 2 - file has an action in it.
438
439=back
440
441A zero or undefined value means this file has neither.
442
443=head4 C<%option>
444
445Stores the debugger options. These are character string values.
446
447=head4 C<%postponed>
448
449Saves breakpoints for code that hasn't been compiled yet.
450Keys are subroutine names, values are:
451
452=over 4
453
454=item * 'compile' - break when this sub is compiled
455
456=item * 'break +0 if <condition>' - break (conditionally) at the start of this routine. The condition will be '1' if no condition was specified.
457
458=back
459
460=head4 C<%postponed_file>
461
462This hash keeps track of breakpoints that need to be set for files that have
463not yet been compiled. Keys are filenames; values are references to hashes.
464Each of these hashes is keyed by line number, and its values are breakpoint
465definitions ("condition\0action").
466
467=head1 DEBUGGER INITIALIZATION
468
469The debugger's initialization actually jumps all over the place inside this
470package. This is because there are several BEGIN blocks (which of course
471execute immediately) spread through the code. Why is that?
472
473The debugger needs to be able to change some things and set some things up
474before the debugger code is compiled; most notably, the C<$deep> variable that
475C<DB::sub> uses to tell when a program has recursed deeply. In addition, the
476debugger has to turn off warnings while the debugger code is compiled, but then
477restore them to their original setting before the program being debugged begins
478executing.
479
480The first C<BEGIN> block simply turns off warnings by saving the current
481setting of C<$^W> and then setting it to zero. The second one initializes
482the debugger variables that are needed before the debugger begins executing.
483The third one puts C<$^X> back to its former value.
484
485We'll detail the second C<BEGIN> block later; just remember that if you need
486to initialize something before the debugger starts really executing, that's
487where it has to go.
488
489=cut
490
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491package DB;
492
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493use IO::Handle;
494
54d04a52 495# Debugger for Perl 5.00x; perl5db.pl patch level:
7fddc82f 496$VERSION = 1.27;
69893cff 497
e22ea7cc 498$header = "perl5db.pl version $VERSION";
d338d6fe 499
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500=head1 DEBUGGER ROUTINES
501
502=head2 C<DB::eval()>
503
504This function replaces straight C<eval()> inside the debugger; it simplifies
505the process of evaluating code in the user's context.
506
507The code to be evaluated is passed via the package global variable
508C<$DB::evalarg>; this is done to avoid fiddling with the contents of C<@_>.
509
510We preserve the current settings of X<C<$trace>>, X<C<$single>>, and X<C<$^D>>;
511add the X<C<$usercontext>> (that's the preserved values of C<$@>, C<$!>,
512C<$^E>, C<$,>, C<$/>, C<$\>, and C<$^W>, grabbed when C<DB::DB> got control,
513and the user's current package) and a add a newline before we do the C<eval()>.
514This causes the proper context to be used when the eval is actually done.
515Afterward, we restore C<$trace>, C<$single>, and C<$^D>.
516
517Next we need to handle C<$@> without getting confused. We save C<$@> in a
518local lexical, localize C<$saved[0]> (which is where C<save()> will put
519C<$@>), and then call C<save()> to capture C<$@>, C<$!>, C<$^E>, C<$,>,
520C<$/>, C<$\>, and C<$^W>) and set C<$,>, C<$/>, C<$\>, and C<$^W> to values
521considered sane by the debugger. If there was an C<eval()> error, we print
522it on the debugger's output. If X<C<$onetimedump>> is defined, we call
523X<C<dumpit>> if it's set to 'dump', or X<C<methods>> if it's set to
524'methods'. Setting it to something else causes the debugger to do the eval
525but not print the result - handy if you want to do something else with it
526(the "watch expressions" code does this to get the value of the watch
527expression but not show it unless it matters).
528
529In any case, we then return the list of output from C<eval> to the caller,
530and unwinding restores the former version of C<$@> in C<@saved> as well
531(the localization of C<$saved[0]> goes away at the end of this scope).
532
533=head3 Parameters and variables influencing execution of DB::eval()
534
535C<DB::eval> isn't parameterized in the standard way; this is to keep the
536debugger's calls to C<DB::eval()> from mucking with C<@_>, among other things.
537The variables listed below influence C<DB::eval()>'s execution directly.
538
539=over 4
540
541=item C<$evalarg> - the thing to actually be eval'ed
542
543=item C<$trace> - Current state of execution tracing (see X<$trace>)
544
545=item C<$single> - Current state of single-stepping (see X<$single>)
546
547=item C<$onetimeDump> - what is to be displayed after the evaluation
548
549=item C<$onetimeDumpDepth> - how deep C<dumpit()> should go when dumping results
550
551=back
552
553The following variables are altered by C<DB::eval()> during its execution. They
554are "stacked" via C<local()>, enabling recursive calls to C<DB::eval()>.
555
556=over 4
557
558=item C<@res> - used to capture output from actual C<eval>.
559
560=item C<$otrace> - saved value of C<$trace>.
561
562=item C<$osingle> - saved value of C<$single>.
563
564=item C<$od> - saved value of C<$^D>.
565
566=item C<$saved[0]> - saved value of C<$@>.
567
568=item $\ - for output of C<$@> if there is an evaluation error.
569
570=back
571
572=head3 The problem of lexicals
573
574The context of C<DB::eval()> presents us with some problems. Obviously,
575we want to be 'sandboxed' away from the debugger's internals when we do
576the eval, but we need some way to control how punctuation variables and
577debugger globals are used.
578
579We can't use local, because the code inside C<DB::eval> can see localized
580variables; and we can't use C<my> either for the same reason. The code
581in this routine compromises and uses C<my>.
582
583After this routine is over, we don't have user code executing in the debugger's
584context, so we can use C<my> freely.
585
586=cut
587
588############################################## Begin lexical danger zone
589
590# 'my' variables used here could leak into (that is, be visible in)
591# the context that the code being evaluated is executing in. This means that
592# the code could modify the debugger's variables.
593#
594# Fiddling with the debugger's context could be Bad. We insulate things as
595# much as we can.
596
c1051fcf 597sub eval {
69893cff 598
c1051fcf 599 # 'my' would make it visible from user code
e22ea7cc 600 # but so does local! --tchrist
69893cff 601 # Remember: this localizes @DB::res, not @main::res.
c1051fcf
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602 local @res;
603 {
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604
605 # Try to keep the user code from messing with us. Save these so that
606 # even if the eval'ed code changes them, we can put them back again.
607 # Needed because the user could refer directly to the debugger's
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608 # package globals (and any 'my' variables in this containing scope)
609 # inside the eval(), and we want to try to stay safe.
e22ea7cc 610 local $otrace = $trace;
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611 local $osingle = $single;
612 local $od = $^D;
613
614 # Untaint the incoming eval() argument.
615 { ($evalarg) = $evalarg =~ /(.*)/s; }
616
e22ea7cc 617 # $usercontext built in DB::DB near the comment
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618 # "set up the context for DB::eval ..."
619 # Evaluate and save any results.
e22ea7cc 620 @res = eval "$usercontext $evalarg;\n"; # '\n' for nice recursive debug
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621
622 # Restore those old values.
623 $trace = $otrace;
624 $single = $osingle;
625 $^D = $od;
c1051fcf 626 }
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627
628 # Save the current value of $@, and preserve it in the debugger's copy
629 # of the saved precious globals.
c1051fcf 630 my $at = $@;
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631
632 # Since we're only saving $@, we only have to localize the array element
633 # that it will be stored in.
e22ea7cc 634 local $saved[0]; # Preserve the old value of $@
c1051fcf 635 eval { &DB::save };
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636
637 # Now see whether we need to report an error back to the user.
c1051fcf 638 if ($at) {
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639 local $\ = '';
640 print $OUT $at;
641 }
642
643 # Display as required by the caller. $onetimeDump and $onetimedumpDepth
644 # are package globals.
645 elsif ($onetimeDump) {
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646 if ( $onetimeDump eq 'dump' ) {
647 local $option{dumpDepth} = $onetimedumpDepth
648 if defined $onetimedumpDepth;
649 dumpit( $OUT, \@res );
650 }
651 elsif ( $onetimeDump eq 'methods' ) {
652 methods( $res[0] );
653 }
69893cff 654 } ## end elsif ($onetimeDump)
c1051fcf 655 @res;
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656} ## end sub eval
657
658############################################## End lexical danger zone
c1051fcf 659
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660# After this point it is safe to introduce lexicals.
661# The code being debugged will be executing in its own context, and
69893cff 662# can't see the inside of the debugger.
d338d6fe 663#
e22ea7cc 664# However, one should not overdo it: leave as much control from outside as
69893cff
RGS
665# possible. If you make something a lexical, it's not going to be addressable
666# from outside the debugger even if you know its name.
667
d338d6fe
PP
668# This file is automatically included if you do perl -d.
669# It's probably not useful to include this yourself.
670#
e22ea7cc 671# Before venturing further into these twisty passages, it is
2f7e9187
MS
672# wise to read the perldebguts man page or risk the ire of dragons.
673#
69893cff
RGS
674# (It should be noted that perldebguts will tell you a lot about
675# the underlying mechanics of how the debugger interfaces into the
676# Perl interpreter, but not a lot about the debugger itself. The new
677# comments in this code try to address this problem.)
678
d338d6fe 679# Note that no subroutine call is possible until &DB::sub is defined
36477c24 680# (for subroutines defined outside of the package DB). In fact the same is
d338d6fe
PP
681# true if $deep is not defined.
682#
69893cff 683# $Log: perldb.pl,v $
055fd3a9
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684
685# Enhanced by ilya@math.ohio-state.edu (Ilya Zakharevich)
055fd3a9
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686
687# modified Perl debugger, to be run from Emacs in perldb-mode
688# Ray Lischner (uunet!mntgfx!lisch) as of 5 Nov 1990
689# Johan Vromans -- upgrade to 4.0 pl 10
690# Ilya Zakharevich -- patches after 5.001 (and some before ;-)
691
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RGS
692# (We have made efforts to clarify the comments in the change log
693# in other places; some of them may seem somewhat obscure as they
694# were originally written, and explaining them away from the code
695# in question seems conterproductive.. -JM)
696
697########################################################################
698# Changes: 0.94
699# + A lot of things changed after 0.94. First of all, core now informs
700# debugger about entry into XSUBs, overloaded operators, tied operations,
701# BEGIN and END. Handy with `O f=2'.
702# + This can make debugger a little bit too verbose, please be patient
703# and report your problems promptly.
704# + Now the option frame has 3 values: 0,1,2. XXX Document!
705# + Note that if DESTROY returns a reference to the object (or object),
706# the deletion of data may be postponed until the next function call,
707# due to the need to examine the return value.
708#
709# Changes: 0.95
710# + `v' command shows versions.
711#
e22ea7cc 712# Changes: 0.96
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RGS
713# + `v' command shows version of readline.
714# primitive completion works (dynamic variables, subs for `b' and `l',
715# options). Can `p %var'
716# + Better help (`h <' now works). New commands <<, >>, {, {{.
717# {dump|print}_trace() coded (to be able to do it from <<cmd).
718# + `c sub' documented.
719# + At last enough magic combined to stop after the end of debuggee.
720# + !! should work now (thanks to Emacs bracket matching an extra
721# `]' in a regexp is caught).
722# + `L', `D' and `A' span files now (as documented).
723# + Breakpoints in `require'd code are possible (used in `R').
724# + Some additional words on internal work of debugger.
725# + `b load filename' implemented.
726# + `b postpone subr' implemented.
727# + now only `q' exits debugger (overwritable on $inhibit_exit).
728# + When restarting debugger breakpoints/actions persist.
e22ea7cc 729# + Buglet: When restarting debugger only one breakpoint/action per
69893cff
RGS
730# autoloaded function persists.
731#
36477c24 732# Changes: 0.97: NonStop will not stop in at_exit().
69893cff
RGS
733# + Option AutoTrace implemented.
734# + Trace printed differently if frames are printed too.
735# + new `inhibitExit' option.
736# + printing of a very long statement interruptible.
1d06cb2d 737# Changes: 0.98: New command `m' for printing possible methods
69893cff
RGS
738# + 'l -' is a synonym for `-'.
739# + Cosmetic bugs in printing stack trace.
740# + `frame' & 8 to print "expanded args" in stack trace.
741# + Can list/break in imported subs.
742# + new `maxTraceLen' option.
743# + frame & 4 and frame & 8 granted.
744# + new command `m'
745# + nonstoppable lines do not have `:' near the line number.
746# + `b compile subname' implemented.
747# + Will not use $` any more.
748# + `-' behaves sane now.
477ea2b1 749# Changes: 0.99: Completion for `f', `m'.
69893cff
RGS
750# + `m' will remove duplicate names instead of duplicate functions.
751# + `b load' strips trailing whitespace.
752# completion ignores leading `|'; takes into account current package
753# when completing a subroutine name (same for `l').
055fd3a9
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754# Changes: 1.07: Many fixed by tchrist 13-March-2000
755# BUG FIXES:
04e43a21 756# + Added bare minimal security checks on perldb rc files, plus
055fd3a9
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757# comments on what else is needed.
758# + Fixed the ornaments that made "|h" completely unusable.
759# They are not used in print_help if they will hurt. Strip pod
760# if we're paging to less.
761# + Fixed mis-formatting of help messages caused by ornaments
e22ea7cc
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762# to restore Larry's original formatting.
763# + Fixed many other formatting errors. The code is still suboptimal,
04e43a21 764# and needs a lot of work at restructuring. It's also misindented
055fd3a9
GS
765# in many places.
766# + Fixed bug where trying to look at an option like your pager
e22ea7cc 767# shows "1".
055fd3a9
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768# + Fixed some $? processing. Note: if you use csh or tcsh, you will
769# lose. You should consider shell escapes not using their shell,
770# or else not caring about detailed status. This should really be
771# unified into one place, too.
772# + Fixed bug where invisible trailing whitespace on commands hoses you,
04e43a21 773# tricking Perl into thinking you weren't calling a debugger command!
055fd3a9
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774# + Fixed bug where leading whitespace on commands hoses you. (One
775# suggests a leading semicolon or any other irrelevant non-whitespace
776# to indicate literal Perl code.)
777# + Fixed bugs that ate warnings due to wrong selected handle.
778# + Fixed a precedence bug on signal stuff.
779# + Fixed some unseemly wording.
780# + Fixed bug in help command trying to call perl method code.
781# + Fixed to call dumpvar from exception handler. SIGPIPE killed us.
782# ENHANCEMENTS:
783# + Added some comments. This code is still nasty spaghetti.
784# + Added message if you clear your pre/post command stacks which was
785# very easy to do if you just typed a bare >, <, or {. (A command
786# without an argument should *never* be a destructive action; this
787# API is fundamentally screwed up; likewise option setting, which
788# is equally buggered.)
789# + Added command stack dump on argument of "?" for >, <, or {.
790# + Added a semi-built-in doc viewer command that calls man with the
791# proper %Config::Config path (and thus gets caching, man -k, etc),
792# or else perldoc on obstreperous platforms.
793# + Added to and rearranged the help information.
794# + Detected apparent misuse of { ... } to declare a block; this used
795# to work but now is a command, and mysteriously gave no complaint.
04e43a21
DL
796#
797# Changes: 1.08: Apr 25, 2001 Jon Eveland <jweveland@yahoo.com>
798# BUG FIX:
799# + This patch to perl5db.pl cleans up formatting issues on the help
800# summary (h h) screen in the debugger. Mostly columnar alignment
801# issues, plus converted the printed text to use all spaces, since
802# tabs don't seem to help much here.
803#
804# Changes: 1.09: May 19, 2001 Ilya Zakharevich <ilya@math.ohio-state.edu>
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RGS
805# Minor bugs corrected;
806# + Support for auto-creation of new TTY window on startup, either
807# unconditionally, or if started as a kid of another debugger session;
808# + New `O'ption CreateTTY
809# I<CreateTTY> bits control attempts to create a new TTY on events:
e22ea7cc 810# 1: on fork()
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RGS
811# 2: debugger is started inside debugger
812# 4: on startup
813# + Code to auto-create a new TTY window on OS/2 (currently one
814# extra window per session - need named pipes to have more...);
815# + Simplified interface for custom createTTY functions (with a backward
816# compatibility hack); now returns the TTY name to use; return of ''
817# means that the function reset the I/O handles itself;
818# + Better message on the semantic of custom createTTY function;
819# + Convert the existing code to create a TTY into a custom createTTY
820# function;
821# + Consistent support for TTY names of the form "TTYin,TTYout";
822# + Switch line-tracing output too to the created TTY window;
823# + make `b fork' DWIM with CORE::GLOBAL::fork;
824# + High-level debugger API cmd_*():
04e43a21
DL
825# cmd_b_load($filenamepart) # b load filenamepart
826# cmd_b_line($lineno [, $cond]) # b lineno [cond]
827# cmd_b_sub($sub [, $cond]) # b sub [cond]
828# cmd_stop() # Control-C
492652be 829# cmd_d($lineno) # d lineno (B)
04e43a21
DL
830# The cmd_*() API returns FALSE on failure; in this case it outputs
831# the error message to the debugging output.
69893cff 832# + Low-level debugger API
04e43a21
DL
833# break_on_load($filename) # b load filename
834# @files = report_break_on_load() # List files with load-breakpoints
835# breakable_line_in_filename($name, $from [, $to])
836# # First breakable line in the
837# # range $from .. $to. $to defaults
e22ea7cc 838# # to $from, and may be less than
69893cff 839# # $to
04e43a21
DL
840# breakable_line($from [, $to]) # Same for the current file
841# break_on_filename_line($name, $lineno [, $cond])
e22ea7cc 842# # Set breakpoint,$cond defaults to
69893cff 843# # 1
04e43a21
DL
844# break_on_filename_line_range($name, $from, $to [, $cond])
845# # As above, on the first
846# # breakable line in range
847# break_on_line($lineno [, $cond]) # As above, in the current file
848# break_subroutine($sub [, $cond]) # break on the first breakable line
849# ($name, $from, $to) = subroutine_filename_lines($sub)
850# # The range of lines of the text
851# The low-level API returns TRUE on success, and die()s on failure.
852#
853# Changes: 1.10: May 23, 2001 Daniel Lewart <d-lewart@uiuc.edu>
854# BUG FIXES:
855# + Fixed warnings generated by "perl -dWe 42"
856# + Corrected spelling errors
857# + Squeezed Help (h) output into 80 columns
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858#
859# Changes: 1.11: May 24, 2001 David Dyck <dcd@tc.fluke.com>
860# + Made "x @INC" work like it used to
861#
862# Changes: 1.12: May 24, 2001 Daniel Lewart <d-lewart@uiuc.edu>
863# + Fixed warnings generated by "O" (Show debugger options)
864# + Fixed warnings generated by "p 42" (Print expression)
6f891d7d 865# Changes: 1.13: Jun 19, 2001 Scott.L.Miller@compaq.com
e22ea7cc 866# + Added windowSize option
2f7e9187
MS
867# Changes: 1.14: Oct 9, 2001 multiple
868# + Clean up after itself on VMS (Charles Lane in 12385)
869# + Adding "@ file" syntax (Peter Scott in 12014)
870# + Debug reloading selfloaded stuff (Ilya Zakharevich in 11457)
871# + $^S and other debugger fixes (Ilya Zakharevich in 11120)
872# + Forgot a my() declaration (Ilya Zakharevich in 11085)
873# Changes: 1.15: Nov 6, 2001 Michael G Schwern <schwern@pobox.com>
874# + Updated 1.14 change log
875# + Added *dbline explainatory comments
876# + Mentioning perldebguts man page
492652be 877# Changes: 1.16: Feb 15, 2002 Mark-Jason Dominus <mjd@plover.com>
69893cff 878# + $onetimeDump improvements
492652be
RF
879# Changes: 1.17: Feb 20, 2002 Richard Foley <richard.foley@rfi.net>
880# Moved some code to cmd_[.]()'s for clarity and ease of handling,
e22ea7cc
RF
881# rationalised the following commands and added cmd_wrapper() to
882# enable switching between old and frighteningly consistent new
492652be
RF
883# behaviours for diehards: 'o CommandSet=pre580' (sigh...)
884# a(add), A(del) # action expr (added del by line)
885# + b(add), B(del) # break [line] (was b,D)
e22ea7cc 886# + w(add), W(del) # watch expr (was W,W)
69893cff 887# # added del by expr
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RF
888# + h(summary), h h(long) # help (hh) (was h h,h)
889# + m(methods), M(modules) # ... (was m,v)
890# + o(option) # lc (was O)
891# + v(view code), V(view Variables) # ... (was w,V)
aef14ef9
RF
892# Changes: 1.18: Mar 17, 2002 Richard Foley <richard.foley@rfi.net>
893# + fixed missing cmd_O bug
471505cc 894# Changes: 1.19: Mar 29, 2002 Spider Boardman
895# + Added missing local()s -- DB::DB is called recursively.
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896# Changes: 1.20: Feb 17, 2003 Richard Foley <richard.foley@rfi.net>
897# + pre'n'post commands no longer trashed with no args
898# + watch val joined out of eval()
69893cff
RGS
899# Changes: 1.21: Jun 04, 2003 Joe McMahon <mcmahon@ibiblio.org>
900# + Added comments and reformatted source. No bug fixes/enhancements.
901# + Includes cleanup by Robin Barker and Jarkko Hietaniemi.
902# Changes: 1.22 Jun 09, 2003 Alex Vandiver <alexmv@MIT.EDU>
903# + Flush stdout/stderr before the debugger prompt is printed.
904# Changes: 1.23: Dec 21, 2003 Dominique Quatravaux
de5e1a3d 905# + Fix a side-effect of bug #24674 in the perl debugger ("odd taint bug")
e219e2fb
RF
906# Changes: 1.24: Mar 03, 2004 Richard Foley <richard.foley@rfi.net>
907# + Added command to save all debugger commands for sourcing later.
908# + Added command to display parent inheritence tree of given class.
909# + Fixed minor newline in history bug.
e22ea7cc
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910# Changes: 1.25: Apr 17, 2004 Richard Foley <richard.foley@rfi.net>
911# + Fixed option bug (setting invalid options + not recognising valid short forms)
912# Changes: 1.26: Apr 22, 2004 Richard Foley <richard.foley@rfi.net>
913# + unfork the 5.8.x and 5.9.x debuggers.
914# + whitespace and assertions call cleanup across versions
915# + H * deletes (resets) history
916# + i now handles Class + blessed objects
7fddc82f
RF
917# Changes: 1.27: May 09, 2004 Richard Foley <richard.foley@rfi.net>
918# + updated pod page references - clunky.
919# + removed windowid restriction for forking into an xterm.
920# + more whitespace again.
921# + wrapped restart and enabled rerun [-n] (go back n steps) command.
ee971a18 922####################################################################
d338d6fe 923
69893cff
RGS
924=head1 DEBUGGER INITIALIZATION
925
926The debugger starts up in phases.
927
928=head2 BASIC SETUP
929
930First, it initializes the environment it wants to run in: turning off
931warnings during its own compilation, defining variables which it will need
932to avoid warnings later, setting itself up to not exit when the program
933terminates, and defaulting to printing return values for the C<r> command.
934
935=cut
936
eda6e075 937# Needed for the statement after exec():
69893cff
RGS
938#
939# This BEGIN block is simply used to switch off warnings during debugger
940# compiliation. Probably it would be better practice to fix the warnings,
941# but this is how it's done at the moment.
eda6e075 942
e22ea7cc
RF
943BEGIN {
944 $ini_warn = $^W;
945 $^W = 0;
946} # Switch compilation warnings off until another BEGIN.
d12a4851
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947
948# test if assertions are supported and actived:
eda6e075 949BEGIN {
e22ea7cc
RF
950 $ini_assertion = eval "sub asserting_test : assertion {1}; 1";
951
d12a4851 952 # $ini_assertion = undef => assertions unsupported,
e22ea7cc 953 # " = 1 => assertions supported
d12a4851
JH
954 # print "\$ini_assertion=$ini_assertion\n";
955}
956
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RGS
957local ($^W) = 0; # Switch run-time warnings off during init.
958
959# This would probably be better done with "use vars", but that wasn't around
960# when this code was originally written. (Neither was "use strict".) And on
961# the principle of not fiddling with something that was working, this was
962# left alone.
963warn( # Do not ;-)
e22ea7cc 964 # These variables control the execution of 'dumpvar.pl'.
69893cff
RGS
965 $dumpvar::hashDepth,
966 $dumpvar::arrayDepth,
967 $dumpvar::dumpDBFiles,
968 $dumpvar::dumpPackages,
969 $dumpvar::quoteHighBit,
970 $dumpvar::printUndef,
971 $dumpvar::globPrint,
972 $dumpvar::usageOnly,
973
974 # used to save @ARGV and extract any debugger-related flags.
975 @ARGS,
976
977 # used to control die() reporting in diesignal()
978 $Carp::CarpLevel,
979
980 # used to prevent multiple entries to diesignal()
981 # (if for instance diesignal() itself dies)
982 $panic,
983
984 # used to prevent the debugger from running nonstop
985 # after a restart
986 $second_time,
987 )
988 if 0;
d338d6fe 989
54d04a52 990# Command-line + PERLLIB:
69893cff 991# Save the contents of @INC before they are modified elsewhere.
54d04a52
IZ
992@ini_INC = @INC;
993
69893cff
RGS
994# This was an attempt to clear out the previous values of various
995# trapped errors. Apparently it didn't help. XXX More info needed!
d338d6fe
PP
996# $prevwarn = $prevdie = $prevbus = $prevsegv = ''; # Does not help?!
997
69893cff
RGS
998# We set these variables to safe values. We don't want to blindly turn
999# off warnings, because other packages may still want them.
e22ea7cc
RF
1000$trace = $signal = $single = 0; # Uninitialized warning suppression
1001 # (local $^W cannot help - other packages!).
69893cff
RGS
1002
1003# Default to not exiting when program finishes; print the return
1004# value when the 'r' command is used to return from a subroutine.
55497cff 1005$inhibit_exit = $option{PrintRet} = 1;
d338d6fe 1006
69893cff
RGS
1007=head1 OPTION PROCESSING
1008
1009The debugger's options are actually spread out over the debugger itself and
1010C<dumpvar.pl>; some of these are variables to be set, while others are
1011subs to be called with a value. To try to make this a little easier to
1012manage, the debugger uses a few data structures to define what options
1013are legal and how they are to be processed.
1014
1015First, the C<@options> array defines the I<names> of all the options that
1016are to be accepted.
1017
1018=cut
1019
1020@options = qw(
e22ea7cc
RF
1021 CommandSet
1022 hashDepth arrayDepth dumpDepth
1023 DumpDBFiles DumpPackages DumpReused
1024 compactDump veryCompact quote
1025 HighBit undefPrint globPrint
1026 PrintRet UsageOnly frame
1027 AutoTrace TTY noTTY
1028 ReadLine NonStop LineInfo
1029 maxTraceLen recallCommand ShellBang
1030 pager tkRunning ornaments
1031 signalLevel warnLevel dieLevel
1032 inhibit_exit ImmediateStop bareStringify
1033 CreateTTY RemotePort windowSize
1034 DollarCaretP OnlyAssertions WarnAssertions
1035);
d12a4851
JH
1036
1037@RememberOnROptions = qw(DollarCaretP OnlyAssertions);
1038
69893cff
RGS
1039=pod
1040
1041Second, C<optionVars> lists the variables that each option uses to save its
1042state.
1043
1044=cut
1045
1046%optionVars = (
e22ea7cc
RF
1047 hashDepth => \$dumpvar::hashDepth,
1048 arrayDepth => \$dumpvar::arrayDepth,
1049 CommandSet => \$CommandSet,
1050 DumpDBFiles => \$dumpvar::dumpDBFiles,
1051 DumpPackages => \$dumpvar::dumpPackages,
1052 DumpReused => \$dumpvar::dumpReused,
1053 HighBit => \$dumpvar::quoteHighBit,
1054 undefPrint => \$dumpvar::printUndef,
1055 globPrint => \$dumpvar::globPrint,
1056 UsageOnly => \$dumpvar::usageOnly,
1057 CreateTTY => \$CreateTTY,
1058 bareStringify => \$dumpvar::bareStringify,
1059 frame => \$frame,
1060 AutoTrace => \$trace,
1061 inhibit_exit => \$inhibit_exit,
1062 maxTraceLen => \$maxtrace,
1063 ImmediateStop => \$ImmediateStop,
1064 RemotePort => \$remoteport,
1065 windowSize => \$window,
1066 WarnAssertions => \$warnassertions,
69893cff
RGS
1067);
1068
1069=pod
1070
1071Third, C<%optionAction> defines the subroutine to be called to process each
1072option.
1073
1074=cut
1075
1076%optionAction = (
1077 compactDump => \&dumpvar::compactDump,
1078 veryCompact => \&dumpvar::veryCompact,
1079 quote => \&dumpvar::quote,
1080 TTY => \&TTY,
1081 noTTY => \&noTTY,
1082 ReadLine => \&ReadLine,
1083 NonStop => \&NonStop,
1084 LineInfo => \&LineInfo,
1085 recallCommand => \&recallCommand,
1086 ShellBang => \&shellBang,
1087 pager => \&pager,
1088 signalLevel => \&signalLevel,
1089 warnLevel => \&warnLevel,
1090 dieLevel => \&dieLevel,
1091 tkRunning => \&tkRunning,
1092 ornaments => \&ornaments,
1093 RemotePort => \&RemotePort,
1094 DollarCaretP => \&DollarCaretP,
1095 OnlyAssertions=> \&OnlyAssertions,
d12a4851
JH
1096);
1097
69893cff
RGS
1098=pod
1099
1100Last, the C<%optionRequire> notes modules that must be C<require>d if an
1101option is used.
1102
1103=cut
d338d6fe 1104
69893cff
RGS
1105# Note that this list is not complete: several options not listed here
1106# actually require that dumpvar.pl be loaded for them to work, but are
1107# not in the table. A subsequent patch will correct this problem; for
1108# the moment, we're just recommenting, and we are NOT going to change
1109# function.
eda6e075 1110%optionRequire = (
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RGS
1111 compactDump => 'dumpvar.pl',
1112 veryCompact => 'dumpvar.pl',
1113 quote => 'dumpvar.pl',
e22ea7cc 1114);
69893cff
RGS
1115
1116=pod
1117
1118There are a number of initialization-related variables which can be set
1119by putting code to set them in a BEGIN block in the C<PERL5DB> environment
1120variable. These are:
1121
1122=over 4
1123
1124=item C<$rl> - readline control XXX needs more explanation
1125
1126=item C<$warnLevel> - whether or not debugger takes over warning handling
1127
1128=item C<$dieLevel> - whether or not debugger takes over die handling
1129
1130=item C<$signalLevel> - whether or not debugger takes over signal handling
1131
1132=item C<$pre> - preprompt actions (array reference)
1133
1134=item C<$post> - postprompt actions (array reference)
1135
1136=item C<$pretype>
1137
1138=item C<$CreateTTY> - whether or not to create a new TTY for this debugger
1139
1140=item C<$CommandSet> - which command set to use (defaults to new, documented set)
1141
1142=back
1143
1144=cut
d338d6fe
PP
1145
1146# These guys may be defined in $ENV{PERL5DB} :
69893cff
RGS
1147$rl = 1 unless defined $rl;
1148$warnLevel = 1 unless defined $warnLevel;
1149$dieLevel = 1 unless defined $dieLevel;
1150$signalLevel = 1 unless defined $signalLevel;
1151$pre = [] unless defined $pre;
1152$post = [] unless defined $post;
1153$pretype = [] unless defined $pretype;
1154$CreateTTY = 3 unless defined $CreateTTY;
1155$CommandSet = '580' unless defined $CommandSet;
1156
1157=pod
1158
1159The default C<die>, C<warn>, and C<signal> handlers are set up.
1160
1161=cut
055fd3a9 1162
d338d6fe
PP
1163warnLevel($warnLevel);
1164dieLevel($dieLevel);
1165signalLevel($signalLevel);
055fd3a9 1166
69893cff
RGS
1167=pod
1168
1169The pager to be used is needed next. We try to get it from the
1170environment first. if it's not defined there, we try to find it in
1171the Perl C<Config.pm>. If it's not there, we default to C<more>. We
1172then call the C<pager()> function to save the pager name.
1173
1174=cut
1175
1176# This routine makes sure $pager is set up so that '|' can use it.
4865a36d 1177pager(
e22ea7cc 1178
69893cff 1179 # If PAGER is defined in the environment, use it.
e22ea7cc
RF
1180 defined $ENV{PAGER}
1181 ? $ENV{PAGER}
69893cff
RGS
1182
1183 # If not, see if Config.pm defines it.
e22ea7cc
RF
1184 : eval { require Config }
1185 && defined $Config::Config{pager}
1186 ? $Config::Config{pager}
69893cff
RGS
1187
1188 # If not, fall back to 'more'.
e22ea7cc
RF
1189 : 'more'
1190 )
1191 unless defined $pager;
69893cff
RGS
1192
1193=pod
1194
1195We set up the command to be used to access the man pages, the command
1196recall character ("!" unless otherwise defined) and the shell escape
1197character ("!" unless otherwise defined). Yes, these do conflict, and
1198neither works in the debugger at the moment.
1199
1200=cut
1201
055fd3a9 1202setman();
69893cff
RGS
1203
1204# Set up defaults for command recall and shell escape (note:
1205# these currently don't work in linemode debugging).
d338d6fe 1206&recallCommand("!") unless defined $prc;
69893cff
RGS
1207&shellBang("!") unless defined $psh;
1208
1209=pod
1210
1211We then set up the gigantic string containing the debugger help.
1212We also set the limit on the number of arguments we'll display during a
1213trace.
1214
1215=cut
1216
04e43a21 1217sethelp();
69893cff
RGS
1218
1219# If we didn't get a default for the length of eval/stack trace args,
1220# set it here.
1d06cb2d 1221$maxtrace = 400 unless defined $maxtrace;
69893cff
RGS
1222
1223=head2 SETTING UP THE DEBUGGER GREETING
1224
1225The debugger 'greeting' helps to inform the user how many debuggers are
1226running, and whether the current debugger is the primary or a child.
1227
1228If we are the primary, we just hang onto our pid so we'll have it when
1229or if we start a child debugger. If we are a child, we'll set things up
1230so we'll have a unique greeting and so the parent will give us our own
1231TTY later.
1232
1233We save the current contents of the C<PERLDB_PIDS> environment variable
1234because we mess around with it. We'll also need to hang onto it because
1235we'll need it if we restart.
1236
1237Child debuggers make a label out of the current PID structure recorded in
1238PERLDB_PIDS plus the new PID. They also mark themselves as not having a TTY
1239yet so the parent will give them one later via C<resetterm()>.
1240
1241=cut
1242
e22ea7cc 1243# Save the current contents of the environment; we're about to
69893cff 1244# much with it. We'll need this if we have to restart.
f1583d8f 1245$ini_pids = $ENV{PERLDB_PIDS};
69893cff 1246
e22ea7cc
RF
1247if ( defined $ENV{PERLDB_PIDS} ) {
1248
69893cff 1249 # We're a child. Make us a label out of the current PID structure
e22ea7cc 1250 # recorded in PERLDB_PIDS plus our (new) PID. Mark us as not having
69893cff 1251 # a term yet so the parent will give us one later via resetterm().
e22ea7cc
RF
1252 $pids = "[$ENV{PERLDB_PIDS}]";
1253 $ENV{PERLDB_PIDS} .= "->$$";
1254 $term_pid = -1;
69893cff
RGS
1255} ## end if (defined $ENV{PERLDB_PIDS...
1256else {
e22ea7cc
RF
1257
1258 # We're the parent PID. Initialize PERLDB_PID in case we end up with a
69893cff
RGS
1259 # child debugger, and mark us as the parent, so we'll know to set up
1260 # more TTY's is we have to.
1261 $ENV{PERLDB_PIDS} = "$$";
e22ea7cc
RF
1262 $pids = "{pid=$$}";
1263 $term_pid = $$;
f1583d8f 1264}
69893cff 1265
f1583d8f 1266$pidprompt = '';
69893cff
RGS
1267
1268# Sets up $emacs as a synonym for $slave_editor.
1269*emacs = $slave_editor if $slave_editor; # May be used in afterinit()...
1270
1271=head2 READING THE RC FILE
1272
1273The debugger will read a file of initialization options if supplied. If
1274running interactively, this is C<.perldb>; if not, it's C<perldb.ini>.
1275
1276=cut
1277
1278# As noted, this test really doesn't check accurately that the debugger
1279# is running at a terminal or not.
d338d6fe 1280
e22ea7cc
RF
1281if ( -e "/dev/tty" ) { # this is the wrong metric!
1282 $rcfile = ".perldb";
1283}
69893cff
RGS
1284else {
1285 $rcfile = "perldb.ini";
d338d6fe
PP
1286}
1287
69893cff
RGS
1288=pod
1289
1290The debugger does a safety test of the file to be read. It must be owned
1291either by the current user or root, and must only be writable by the owner.
1292
1293=cut
1294
1295# This wraps a safety test around "do" to read and evaluate the init file.
1296#
055fd3a9
GS
1297# This isn't really safe, because there's a race
1298# between checking and opening. The solution is to
1299# open and fstat the handle, but then you have to read and
1300# eval the contents. But then the silly thing gets
69893cff
RGS
1301# your lexical scope, which is unfortunate at best.
1302sub safe_do {
055fd3a9
GS
1303 my $file = shift;
1304
1305 # Just exactly what part of the word "CORE::" don't you understand?
69893cff
RGS
1306 local $SIG{__WARN__};
1307 local $SIG{__DIE__};
055fd3a9 1308
e22ea7cc 1309 unless ( is_safe_file($file) ) {
69893cff 1310 CORE::warn <<EO_GRIPE;
055fd3a9
GS
1311perldb: Must not source insecure rcfile $file.
1312 You or the superuser must be the owner, and it must not
69893cff 1313 be writable by anyone but its owner.
055fd3a9 1314EO_GRIPE
69893cff
RGS
1315 return;
1316 } ## end unless (is_safe_file($file...
055fd3a9
GS
1317
1318 do $file;
1319 CORE::warn("perldb: couldn't parse $file: $@") if $@;
69893cff 1320} ## end sub safe_do
055fd3a9 1321
69893cff
RGS
1322# This is the safety test itself.
1323#
055fd3a9
GS
1324# Verifies that owner is either real user or superuser and that no
1325# one but owner may write to it. This function is of limited use
1326# when called on a path instead of upon a handle, because there are
1327# no guarantees that filename (by dirent) whose file (by ino) is
e22ea7cc 1328# eventually accessed is the same as the one tested.
055fd3a9
GS
1329# Assumes that the file's existence is not in doubt.
1330sub is_safe_file {
1331 my $path = shift;
69893cff 1332 stat($path) || return; # mysteriously vaporized
e22ea7cc 1333 my ( $dev, $ino, $mode, $nlink, $uid, $gid ) = stat(_);
055fd3a9
GS
1334
1335 return 0 if $uid != 0 && $uid != $<;
1336 return 0 if $mode & 022;
1337 return 1;
69893cff 1338} ## end sub is_safe_file
055fd3a9 1339
69893cff 1340# If the rcfile (whichever one we decided was the right one to read)
e22ea7cc
RF
1341# exists, we safely do it.
1342if ( -f $rcfile ) {
055fd3a9 1343 safe_do("./$rcfile");
69893cff 1344}
e22ea7cc 1345
69893cff 1346# If there isn't one here, try the user's home directory.
e22ea7cc 1347elsif ( defined $ENV{HOME} && -f "$ENV{HOME}/$rcfile" ) {
055fd3a9
GS
1348 safe_do("$ENV{HOME}/$rcfile");
1349}
e22ea7cc 1350
69893cff 1351# Else try the login directory.
e22ea7cc 1352elsif ( defined $ENV{LOGDIR} && -f "$ENV{LOGDIR}/$rcfile" ) {
055fd3a9 1353 safe_do("$ENV{LOGDIR}/$rcfile");
d338d6fe
PP
1354}
1355
69893cff 1356# If the PERLDB_OPTS variable has options in it, parse those out next.
e22ea7cc
RF
1357if ( defined $ENV{PERLDB_OPTS} ) {
1358 parse_options( $ENV{PERLDB_OPTS} );
d338d6fe
PP
1359}
1360
69893cff
RGS
1361=pod
1362
1363The last thing we do during initialization is determine which subroutine is
1364to be used to obtain a new terminal when a new debugger is started. Right now,
1365the debugger only handles X Windows and OS/2.
1366
1367=cut
1368
1369# Set up the get_fork_TTY subroutine to be aliased to the proper routine.
1370# Works if you're running an xterm or xterm-like window, or you're on
1371# OS/2. This may need some expansion: for instance, this doesn't handle
e22ea7cc
RF
1372# OS X Terminal windows.
1373
1374if (
1375 not defined &get_fork_TTY # no routine exists,
1376 and defined $ENV{TERM} # and we know what kind
1377 # of terminal this is,
1378 and $ENV{TERM} eq 'xterm' # and it's an xterm,
7fddc82f
RF
1379# and defined $ENV{WINDOWID} # and we know what window this is, <- wrong metric
1380 and defined $ENV{DISPLAY} # and what display it's on,
1381 )
69893cff 1382{
e22ea7cc 1383 *get_fork_TTY = \&xterm_get_fork_TTY; # use the xterm version
69893cff 1384} ## end if (not defined &get_fork_TTY...
e22ea7cc
RF
1385elsif ( $^O eq 'os2' ) { # If this is OS/2,
1386 *get_fork_TTY = \&os2_get_fork_TTY; # use the OS/2 version
f1583d8f 1387}
e22ea7cc 1388
dbb46cec
DQ
1389# untaint $^O, which may have been tainted by the last statement.
1390# see bug [perl #24674]
e22ea7cc
RF
1391$^O =~ m/^(.*)\z/;
1392$^O = $1;
f1583d8f 1393
d12a4851 1394# Here begin the unreadable code. It needs fixing.
055fd3a9 1395
69893cff
RGS
1396=head2 RESTART PROCESSING
1397
1398This section handles the restart command. When the C<R> command is invoked, it
1399tries to capture all of the state it can into environment variables, and
1400then sets C<PERLDB_RESTART>. When we start executing again, we check to see
1401if C<PERLDB_RESTART> is there; if so, we reload all the information that
1402the R command stuffed into the environment variables.
1403
1404 PERLDB_RESTART - flag only, contains no restart data itself.
1405 PERLDB_HIST - command history, if it's available
1406 PERLDB_ON_LOAD - breakpoints set by the rc file
1407 PERLDB_POSTPONE - subs that have been loaded/not executed, and have actions
1408 PERLDB_VISITED - files that had breakpoints
1409 PERLDB_FILE_... - breakpoints for a file
1410 PERLDB_OPT - active options
1411 PERLDB_INC - the original @INC
1412 PERLDB_PRETYPE - preprompt debugger actions
1413 PERLDB_PRE - preprompt Perl code
1414 PERLDB_POST - post-prompt Perl code
1415 PERLDB_TYPEAHEAD - typeahead captured by readline()
1416
1417We chug through all these variables and plug the values saved in them
1418back into the appropriate spots in the debugger.
1419
1420=cut
1421
e22ea7cc
RF
1422if ( exists $ENV{PERLDB_RESTART} ) {
1423
69893cff 1424 # We're restarting, so we don't need the flag that says to restart anymore.
e22ea7cc
RF
1425 delete $ENV{PERLDB_RESTART};
1426
1427 # $restart = 1;
1428 @hist = get_list('PERLDB_HIST');
1429 %break_on_load = get_list("PERLDB_ON_LOAD");
1430 %postponed = get_list("PERLDB_POSTPONE");
69893cff
RGS
1431
1432 # restore breakpoints/actions
e22ea7cc
RF
1433 my @had_breakpoints = get_list("PERLDB_VISITED");
1434 for ( 0 .. $#had_breakpoints ) {
1435 my %pf = get_list("PERLDB_FILE_$_");
1436 $postponed_file{ $had_breakpoints[$_] } = \%pf if %pf;
1437 }
69893cff
RGS
1438
1439 # restore options
e22ea7cc
RF
1440 my %opt = get_list("PERLDB_OPT");
1441 my ( $opt, $val );
1442 while ( ( $opt, $val ) = each %opt ) {
1443 $val =~ s/[\\\']/\\$1/g;
1444 parse_options("$opt'$val'");
1445 }
69893cff
RGS
1446
1447 # restore original @INC
e22ea7cc
RF
1448 @INC = get_list("PERLDB_INC");
1449 @ini_INC = @INC;
1450
1451 # return pre/postprompt actions and typeahead buffer
1452 $pretype = [ get_list("PERLDB_PRETYPE") ];
1453 $pre = [ get_list("PERLDB_PRE") ];
1454 $post = [ get_list("PERLDB_POST") ];
1455 @typeahead = get_list( "PERLDB_TYPEAHEAD", @typeahead );
69893cff
RGS
1456} ## end if (exists $ENV{PERLDB_RESTART...
1457
1458=head2 SETTING UP THE TERMINAL
1459
1460Now, we'll decide how the debugger is going to interact with the user.
1461If there's no TTY, we set the debugger to run non-stop; there's not going
1462to be anyone there to enter commands.
1463
1464=cut
54d04a52 1465
d338d6fe 1466if ($notty) {
69893cff
RGS
1467 $runnonstop = 1;
1468}
d12a4851 1469
69893cff
RGS
1470=pod
1471
1472If there is a TTY, we have to determine who it belongs to before we can
1473proceed. If this is a slave editor or graphical debugger (denoted by
1474the first command-line switch being '-emacs'), we shift this off and
1475set C<$rl> to 0 (XXX ostensibly to do straight reads).
1476
1477=cut
1478
1479else {
e22ea7cc 1480
69893cff
RGS
1481 # Is Perl being run from a slave editor or graphical debugger?
1482 # If so, don't use readline, and set $slave_editor = 1.
e22ea7cc
RF
1483 $slave_editor =
1484 ( ( defined $main::ARGV[0] ) and ( $main::ARGV[0] eq '-emacs' ) );
1485 $rl = 0, shift(@main::ARGV) if $slave_editor;
1486
1487 #require Term::ReadLine;
d12a4851 1488
69893cff
RGS
1489=pod
1490
1491We then determine what the console should be on various systems:
1492
1493=over 4
1494
1495=item * Cygwin - We use C<stdin> instead of a separate device.
1496
1497=cut
1498
e22ea7cc
RF
1499 if ( $^O eq 'cygwin' ) {
1500
69893cff
RGS
1501 # /dev/tty is binary. use stdin for textmode
1502 undef $console;
1503 }
1504
1505=item * Unix - use C</dev/tty>.
1506
1507=cut
1508
e22ea7cc 1509 elsif ( -e "/dev/tty" ) {
69893cff
RGS
1510 $console = "/dev/tty";
1511 }
1512
1513=item * Windows or MSDOS - use C<con>.
1514
1515=cut
1516
e22ea7cc 1517 elsif ( $^O eq 'dos' or -e "con" or $^O eq 'MSWin32' ) {
69893cff
RGS
1518 $console = "con";
1519 }
1520
1521=item * MacOS - use C<Dev:Console:Perl Debug> if this is the MPW version; C<Dev:
1522Console> if not. (Note that Mac OS X returns 'darwin', not 'MacOS'. Also note that the debugger doesn't do anything special for 'darwin'. Maybe it should.)
1523
1524=cut
1525
e22ea7cc
RF
1526 elsif ( $^O eq 'MacOS' ) {
1527 if ( $MacPerl::Version !~ /MPW/ ) {
1528 $console =
1529 "Dev:Console:Perl Debug"; # Separate window for application
69893cff
RGS
1530 }
1531 else {
1532 $console = "Dev:Console";
1533 }
1534 } ## end elsif ($^O eq 'MacOS')
1535
1536=item * VMS - use C<sys$command>.
1537
1538=cut
1539
1540 else {
e22ea7cc 1541
69893cff
RGS
1542 # everything else is ...
1543 $console = "sys\$command";
d12a4851 1544 }
69893cff
RGS
1545
1546=pod
1547
1548=back
1549
1550Several other systems don't use a specific console. We C<undef $console>
1551for those (Windows using a slave editor/graphical debugger, NetWare, OS/2
1552with a slave editor, Epoc).
1553
1554=cut
d12a4851 1555
e22ea7cc
RF
1556 if ( ( $^O eq 'MSWin32' ) and ( $slave_editor or defined $ENV{EMACS} ) ) {
1557
69893cff 1558 # /dev/tty is binary. use stdin for textmode
e22ea7cc
RF
1559 $console = undef;
1560 }
1561
1562 if ( $^O eq 'NetWare' ) {
d12a4851 1563
69893cff
RGS
1564 # /dev/tty is binary. use stdin for textmode
1565 $console = undef;
1566 }
d12a4851 1567
69893cff
RGS
1568 # In OS/2, we need to use STDIN to get textmode too, even though
1569 # it pretty much looks like Unix otherwise.
e22ea7cc
RF
1570 if ( defined $ENV{OS2_SHELL} and ( $slave_editor or $ENV{WINDOWID} ) )
1571 { # In OS/2
1572 $console = undef;
1573 }
1574
1575 # EPOC also falls into the 'got to use STDIN' camp.
1576 if ( $^O eq 'epoc' ) {
1577 $console = undef;
1578 }
d12a4851 1579
69893cff
RGS
1580=pod
1581
1582If there is a TTY hanging around from a parent, we use that as the console.
1583
1584=cut
1585
e22ea7cc 1586 $console = $tty if defined $tty;
d12a4851 1587
69893cff
RGS
1588=head2 SOCKET HANDLING
1589
1590The debugger is capable of opening a socket and carrying out a debugging
1591session over the socket.
1592
1593If C<RemotePort> was defined in the options, the debugger assumes that it
1594should try to start a debugging session on that port. It builds the socket
1595and then tries to connect the input and output filehandles to it.
1596
1597=cut
1598
1599 # Handle socket stuff.
e22ea7cc
RF
1600
1601 if ( defined $remoteport ) {
1602
69893cff
RGS
1603 # If RemotePort was defined in the options, connect input and output
1604 # to the socket.
e22ea7cc
RF
1605 require IO::Socket;
1606 $OUT = new IO::Socket::INET(
1607 Timeout => '10',
1608 PeerAddr => $remoteport,
1609 Proto => 'tcp',
69893cff 1610 );
e22ea7cc
RF
1611 if ( !$OUT ) { die "Unable to connect to remote host: $remoteport\n"; }
1612 $IN = $OUT;
69893cff
RGS
1613 } ## end if (defined $remoteport)
1614
1615=pod
1616
1617If no C<RemotePort> was defined, and we want to create a TTY on startup,
1618this is probably a situation where multiple debuggers are running (for example,
1619a backticked command that starts up another debugger). We create a new IN and
1620OUT filehandle, and do the necessary mojo to create a new TTY if we know how
1621and if we can.
1622
1623=cut
1624
1625 # Non-socket.
1626 else {
e22ea7cc 1627
69893cff
RGS
1628 # Two debuggers running (probably a system or a backtick that invokes
1629 # the debugger itself under the running one). create a new IN and OUT
e22ea7cc 1630 # filehandle, and do the necessary mojo to create a new tty if we
69893cff 1631 # know how, and we can.
e22ea7cc
RF
1632 create_IN_OUT(4) if $CreateTTY & 4;
1633 if ($console) {
1634
69893cff
RGS
1635 # If we have a console, check to see if there are separate ins and
1636 # outs to open. (They are assumed identiical if not.)
1637
e22ea7cc
RF
1638 my ( $i, $o ) = split /,/, $console;
1639 $o = $i unless defined $o;
69893cff 1640
69893cff 1641 # read/write on in, or just read, or read on STDIN.
e22ea7cc
RF
1642 open( IN, "+<$i" )
1643 || open( IN, "<$i" )
1644 || open( IN, "<&STDIN" );
1645
69893cff
RGS
1646 # read/write/create/clobber out, or write/create/clobber out,
1647 # or merge with STDERR, or merge with STDOUT.
e22ea7cc
RF
1648 open( OUT, "+>$o" )
1649 || open( OUT, ">$o" )
1650 || open( OUT, ">&STDERR" )
1651 || open( OUT, ">&STDOUT" ); # so we don't dongle stdout
1652
1653 } ## end if ($console)
1654 elsif ( not defined $console ) {
1655
1656 # No console. Open STDIN.
1657 open( IN, "<&STDIN" );
1658
1659 # merge with STDERR, or with STDOUT.
1660 open( OUT, ">&STDERR" )
1661 || open( OUT, ">&STDOUT" ); # so we don't dongle stdout
1662 $console = 'STDIN/OUT';
69893cff
RGS
1663 } ## end elsif (not defined $console)
1664
1665 # Keep copies of the filehandles so that when the pager runs, it
1666 # can close standard input without clobbering ours.
e22ea7cc
RF
1667 $IN = \*IN, $OUT = \*OUT if $console or not defined $console;
1668 } ## end elsif (from if(defined $remoteport))
1669
1670 # Unbuffer DB::OUT. We need to see responses right away.
1671 my $previous = select($OUT);
1672 $| = 1; # for DB::OUT
1673 select($previous);
1674
1675 # Line info goes to debugger output unless pointed elsewhere.
1676 # Pointing elsewhere makes it possible for slave editors to
1677 # keep track of file and position. We have both a filehandle
1678 # and a I/O description to keep track of.
1679 $LINEINFO = $OUT unless defined $LINEINFO;
1680 $lineinfo = $console unless defined $lineinfo;
1681
69893cff
RGS
1682=pod
1683
1684To finish initialization, we show the debugger greeting,
1685and then call the C<afterinit()> subroutine if there is one.
1686
1687=cut
d12a4851 1688
e22ea7cc
RF
1689 # Show the debugger greeting.
1690 $header =~ s/.Header: ([^,]+),v(\s+\S+\s+\S+).*$/$1$2/;
1691 unless ($runnonstop) {
1692 local $\ = '';
1693 local $, = '';
1694 if ( $term_pid eq '-1' ) {
1695 print $OUT "\nDaughter DB session started...\n";
1696 }
1697 else {
1698 print $OUT "\nLoading DB routines from $header\n";
1699 print $OUT (
1700 "Editor support ",
1701 $slave_editor ? "enabled" : "available", ".\n"
1702 );
1703 print $OUT
69893cff
RGS
1704"\nEnter h or `h h' for help, or `$doccmd perldebug' for more help.\n\n";
1705 } ## end else [ if ($term_pid eq '-1')
1706 } ## end unless ($runnonstop)
1707} ## end else [ if ($notty)
1708
1709# XXX This looks like a bug to me.
1710# Why copy to @ARGS and then futz with @args?
d338d6fe
PP
1711@ARGS = @ARGV;
1712for (@args) {
69893cff
RGS
1713 # Make sure backslashes before single quotes are stripped out, and
1714 # keep args unless they are numeric (XXX why?)
e22ea7cc
RF
1715 # s/\'/\\\'/g; # removed while not justified understandably
1716 # s/(.*)/'$1'/ unless /^-?[\d.]+$/; # ditto
d338d6fe
PP
1717}
1718
e22ea7cc 1719# If there was an afterinit() sub defined, call it. It will get
69893cff 1720# executed in our scope, so it can fiddle with debugger globals.
e22ea7cc 1721if ( defined &afterinit ) { # May be defined in $rcfile
69893cff 1722 &afterinit();
d338d6fe 1723}
e22ea7cc 1724
69893cff 1725# Inform us about "Stack dump during die enabled ..." in dieLevel().
43aed9ee
IZ
1726$I_m_init = 1;
1727
d338d6fe
PP
1728############################################################ Subroutines
1729
69893cff
RGS
1730=head1 SUBROUTINES
1731
1732=head2 DB
1733
1734This gigantic subroutine is the heart of the debugger. Called before every
1735statement, its job is to determine if a breakpoint has been reached, and
1736stop if so; read commands from the user, parse them, and execute
1737them, and hen send execution off to the next statement.
1738
1739Note that the order in which the commands are processed is very important;
1740some commands earlier in the loop will actually alter the C<$cmd> variable
1741to create other commands to be executed later. This is all highly "optimized"
1742but can be confusing. Check the comments for each C<$cmd ... && do {}> to
1743see what's happening in any given command.
1744
1745=cut
1746
d338d6fe 1747sub DB {
69893cff
RGS
1748
1749 # Check for whether we should be running continuously or not.
36477c24 1750 # _After_ the perl program is compiled, $single is set to 1:
e22ea7cc
RF
1751 if ( $single and not $second_time++ ) {
1752
69893cff 1753 # Options say run non-stop. Run until we get an interrupt.
e22ea7cc
RF
1754 if ($runnonstop) { # Disable until signal
1755 # If there's any call stack in place, turn off single
1756 # stepping into subs throughout the stack.
1757 for ( $i = 0 ; $i <= $stack_depth ; ) {
1758 $stack[ $i++ ] &= ~1;
1759 }
1760
69893cff 1761 # And we are now no longer in single-step mode.
e22ea7cc 1762 $single = 0;
69893cff
RGS
1763
1764 # If we simply returned at this point, we wouldn't get
1765 # the trace info. Fall on through.
e22ea7cc 1766 # return;
69893cff
RGS
1767 } ## end if ($runnonstop)
1768
e22ea7cc
RF
1769 elsif ($ImmediateStop) {
1770
1771 # We are supposed to stop here; XXX probably a break.
1772 $ImmediateStop = 0; # We've processed it; turn it off
1773 $signal = 1; # Simulate an interrupt to force
1774 # us into the command loop
69893cff
RGS
1775 }
1776 } ## end if ($single and not $second_time...
1777
1778 # If we're in single-step mode, or an interrupt (real or fake)
1779 # has occurred, turn off non-stop mode.
1780 $runnonstop = 0 if $single or $signal;
1781
1782 # Preserve current values of $@, $!, $^E, $,, $/, $\, $^W.
1783 # The code being debugged may have altered them.
d338d6fe 1784 &save;
69893cff
RGS
1785
1786 # Since DB::DB gets called after every line, we can use caller() to
1787 # figure out where we last were executing. Sneaky, eh? This works because
e22ea7cc 1788 # caller is returning all the extra information when called from the
69893cff 1789 # debugger.
e22ea7cc 1790 local ( $package, $filename, $line ) = caller;
471505cc 1791 local $filename_ini = $filename;
69893cff
RGS
1792
1793 # set up the context for DB::eval, so it can properly execute
1794 # code on behalf of the user. We add the package in so that the
1795 # code is eval'ed in the proper package (not in the debugger!).
1796 local $usercontext =
e22ea7cc 1797 '($@, $!, $^E, $,, $/, $\, $^W) = @saved;' . "package $package;";
69893cff
RGS
1798
1799 # Create an alias to the active file magical array to simplify
1800 # the code here.
e22ea7cc 1801 local (*dbline) = $main::{ '_<' . $filename };
aa057b67
CN
1802
1803 # we need to check for pseudofiles on Mac OS (these are files
1804 # not attached to a filename, but instead stored in Dev:Pseudo)
e22ea7cc
RF
1805 if ( $^O eq 'MacOS' && $#dbline < 0 ) {
1806 $filename_ini = $filename = 'Dev:Pseudo';
1807 *dbline = $main::{ '_<' . $filename };
aa057b67
CN
1808 }
1809
69893cff 1810 # Last line in the program.
471505cc 1811 local $max = $#dbline;
69893cff
RGS
1812
1813 # if we have something here, see if we should break.
e22ea7cc
RF
1814 if ( $dbline{$line}
1815 && ( ( $stop, $action ) = split( /\0/, $dbline{$line} ) ) )
1816 {
1817
69893cff 1818 # Stop if the stop criterion says to just stop.
e22ea7cc 1819 if ( $stop eq '1' ) {
69893cff
RGS
1820 $signal |= 1;
1821 }
e22ea7cc 1822
69893cff
RGS
1823 # It's a conditional stop; eval it in the user's context and
1824 # see if we should stop. If so, remove the one-time sigil.
1825 elsif ($stop) {
e22ea7cc 1826 $evalarg = "\$DB::signal |= 1 if do {$stop}";
69893cff
RGS
1827 &eval;
1828 $dbline{$line} =~ s/;9($|\0)/$1/;
1829 }
1830 } ## end if ($dbline{$line} && ...
1831
1832 # Preserve the current stop-or-not, and see if any of the W
1833 # (watch expressions) has changed.
36477c24 1834 my $was_signal = $signal;
69893cff
RGS
1835
1836 # If we have any watch expressions ...
e22ea7cc
RF
1837 if ( $trace & 2 ) {
1838 for ( my $n = 0 ; $n <= $#to_watch ; $n++ ) {
1839 $evalarg = $to_watch[$n];
1840 local $onetimeDump; # Tell DB::eval() to not output results
69893cff
RGS
1841
1842 # Fix context DB::eval() wants to return an array, but
1843 # we need a scalar here.
e22ea7cc
RF
1844 my ($val) = join( "', '", &eval );
1845 $val = ( ( defined $val ) ? "'$val'" : 'undef' );
69893cff
RGS
1846
1847 # Did it change?
e22ea7cc
RF
1848 if ( $val ne $old_watch[$n] ) {
1849
69893cff 1850 # Yep! Show the difference, and fake an interrupt.
e22ea7cc
RF
1851 $signal = 1;
1852 print $OUT <<EOP;
405ff068 1853Watchpoint $n:\t$to_watch[$n] changed:
69893cff
RGS
1854 old value:\t$old_watch[$n]
1855 new value:\t$val
6027b9a3 1856EOP
e22ea7cc 1857 $old_watch[$n] = $val;
69893cff
RGS
1858 } ## end if ($val ne $old_watch...
1859 } ## end for (my $n = 0 ; $n <= ...
1860 } ## end if ($trace & 2)
1861
1862=head2 C<watchfunction()>
1863
1864C<watchfunction()> is a function that can be defined by the user; it is a
1865function which will be run on each entry to C<DB::DB>; it gets the
1866current package, filename, and line as its parameters.
1867
1868The watchfunction can do anything it likes; it is executing in the
1869debugger's context, so it has access to all of the debugger's internal
1870data structures and functions.
1871
1872C<watchfunction()> can control the debugger's actions. Any of the following
1873will cause the debugger to return control to the user's program after
1874C<watchfunction()> executes:
1875
1876=over 4
1877
1878=item * Returning a false value from the C<watchfunction()> itself.
1879
1880=item * Altering C<$single> to a false value.
1881
1882=item * Altering C<$signal> to a false value.
1883
1884=item * Turning off the '4' bit in C<$trace> (this also disables the
1885check for C<watchfunction()>. This can be done with
1886
1887 $trace &= ~4;
1888
1889=back
1890
1891=cut
1892
e22ea7cc 1893 # If there's a user-defined DB::watchfunction, call it with the
69893cff
RGS
1894 # current package, filename, and line. The function executes in
1895 # the DB:: package.
e22ea7cc
RF
1896 if ( $trace & 4 ) { # User-installed watch
1897 return
1898 if watchfunction( $package, $filename, $line )
1899 and not $single
1900 and not $was_signal
1901 and not( $trace & ~4 );
69893cff
RGS
1902 } ## end if ($trace & 4)
1903
e22ea7cc 1904 # Pick up any alteration to $signal in the watchfunction, and
69893cff 1905 # turn off the signal now.
6027b9a3 1906 $was_signal = $signal;
69893cff
RGS
1907 $signal = 0;
1908
1909=head2 GETTING READY TO EXECUTE COMMANDS
1910
1911The debugger decides to take control if single-step mode is on, the
1912C<t> command was entered, or the user generated a signal. If the program
1913has fallen off the end, we set things up so that entering further commands
1914won't cause trouble, and we say that the program is over.
1915
1916=cut
1917
1918 # Check to see if we should grab control ($single true,
1919 # trace set appropriately, or we got a signal).
e22ea7cc
RF
1920 if ( $single || ( $trace & 1 ) || $was_signal ) {
1921
69893cff 1922 # Yes, grab control.
e22ea7cc
RF
1923 if ($slave_editor) {
1924
69893cff 1925 # Tell the editor to update its position.
e22ea7cc
RF
1926 $position = "\032\032$filename:$line:0\n";
1927 print_lineinfo($position);
1928 }
69893cff
RGS
1929
1930=pod
1931
1932Special check: if we're in package C<DB::fake>, we've gone through the
1933C<END> block at least once. We set up everything so that we can continue
1934to enter commands and have a valid context to be in.
1935
1936=cut
1937
e22ea7cc 1938 elsif ( $package eq 'DB::fake' ) {
69893cff 1939
69893cff 1940 # Fallen off the end already.
e22ea7cc
RF
1941 $term || &setterm;
1942 print_help(<<EOP);
405ff068
IZ
1943Debugged program terminated. Use B<q> to quit or B<R> to restart,
1944 use B<O> I<inhibit_exit> to avoid stopping after program termination,
1945 B<h q>, B<h R> or B<h O> to get additional info.
1946EOP
e22ea7cc 1947
69893cff 1948 # Set the DB::eval context appropriately.
e22ea7cc
RF
1949 $package = 'main';
1950 $usercontext =
1951 '($@, $!, $^E, $,, $/, $\, $^W) = @saved;'
1952 . "package $package;"; # this won't let them modify, alas
69893cff 1953 } ## end elsif ($package eq 'DB::fake')
e219e2fb 1954
69893cff 1955=pod
e219e2fb 1956
69893cff
RGS
1957If the program hasn't finished executing, we scan forward to the
1958next executable line, print that out, build the prompt from the file and line
1959number information, and print that.
e219e2fb 1960
69893cff
RGS
1961=cut
1962
e22ea7cc
RF
1963 else {
1964
69893cff
RGS
1965 # Still somewhere in the midst of execution. Set up the
1966 # debugger prompt.
1967 $sub =~ s/\'/::/; # Swap Perl 4 package separators (') to
e22ea7cc 1968 # Perl 5 ones (sorry, we don't print Klingon
69893cff
RGS
1969 #module names)
1970
e22ea7cc
RF
1971 $prefix = $sub =~ /::/ ? "" : "${'package'}::";
1972 $prefix .= "$sub($filename:";
1973 $after = ( $dbline[$line] =~ /\n$/ ? '' : "\n" );
69893cff
RGS
1974
1975 # Break up the prompt if it's really long.
e22ea7cc
RF
1976 if ( length($prefix) > 30 ) {
1977 $position = "$prefix$line):\n$line:\t$dbline[$line]$after";
1978 $prefix = "";
1979 $infix = ":\t";
1980 }
1981 else {
1982 $infix = "):\t";
1983 $position = "$prefix$line$infix$dbline[$line]$after";
1984 }
69893cff
RGS
1985
1986 # Print current line info, indenting if necessary.
e22ea7cc
RF
1987 if ($frame) {
1988 print_lineinfo( ' ' x $stack_depth,
1989 "$line:\t$dbline[$line]$after" );
1990 }
1991 else {
1992 print_lineinfo($position);
1993 }
69893cff
RGS
1994
1995 # Scan forward, stopping at either the end or the next
1996 # unbreakable line.
e22ea7cc
RF
1997 for ( $i = $line + 1 ; $i <= $max && $dbline[$i] == 0 ; ++$i )
1998 { #{ vi
69893cff
RGS
1999
2000 # Drop out on null statements, block closers, and comments.
2001 last if $dbline[$i] =~ /^\s*[\;\}\#\n]/;
2002
2003 # Drop out if the user interrupted us.
2004 last if $signal;
2005
2006 # Append a newline if the line doesn't have one. Can happen
2007 # in eval'ed text, for instance.
e22ea7cc 2008 $after = ( $dbline[$i] =~ /\n$/ ? '' : "\n" );
69893cff
RGS
2009
2010 # Next executable line.
2011 $incr_pos = "$prefix$i$infix$dbline[$i]$after";
2012 $position .= $incr_pos;
2013 if ($frame) {
e22ea7cc 2014
69893cff 2015 # Print it indented if tracing is on.
e22ea7cc
RF
2016 print_lineinfo( ' ' x $stack_depth,
2017 "$i:\t$dbline[$i]$after" );
69893cff
RGS
2018 }
2019 else {
2020 print_lineinfo($incr_pos);
2021 }
2022 } ## end for ($i = $line + 1 ; $i...
2023 } ## end else [ if ($slave_editor)
2024 } ## end if ($single || ($trace...
2025
2026=pod
2027
2028If there's an action to be executed for the line we stopped at, execute it.
2029If there are any preprompt actions, execute those as well.
e219e2fb
RF
2030
2031=cut
2032
69893cff
RGS
2033 # If there's an action, do it now.
2034 $evalarg = $action, &eval if $action;
e219e2fb 2035
69893cff
RGS
2036 # Are we nested another level (e.g., did we evaluate a function
2037 # that had a breakpoint in it at the debugger prompt)?
e22ea7cc
RF
2038 if ( $single || $was_signal ) {
2039
69893cff 2040 # Yes, go down a level.
e22ea7cc 2041 local $level = $level + 1;
69893cff
RGS
2042
2043 # Do any pre-prompt actions.
e22ea7cc
RF
2044 foreach $evalarg (@$pre) {
2045 &eval;
2046 }
69893cff
RGS
2047
2048 # Complain about too much recursion if we passed the limit.
e22ea7cc 2049 print $OUT $stack_depth . " levels deep in subroutine calls!\n"
69893cff
RGS
2050 if $single & 4;
2051
2052 # The line we're currently on. Set $incr to -1 to stay here
2053 # until we get a command that tells us to advance.
e22ea7cc
RF
2054 $start = $line;
2055 $incr = -1; # for backward motion.
69893cff
RGS
2056
2057 # Tack preprompt debugger actions ahead of any actual input.
e22ea7cc 2058 @typeahead = ( @$pretype, @typeahead );
69893cff
RGS
2059
2060=head2 WHERE ARE WE?
2061
2062XXX Relocate this section?
2063
2064The debugger normally shows the line corresponding to the current line of
2065execution. Sometimes, though, we want to see the next line, or to move elsewhere
2066in the file. This is done via the C<$incr>, C<$start>, and C<$max> variables.
2067
2068C<$incr> controls by how many lines the "current" line should move forward
2069after a command is executed. If set to -1, this indicates that the "current"
2070line shouldn't change.
2071
2072C<$start> is the "current" line. It is used for things like knowing where to
2073move forwards or backwards from when doing an C<L> or C<-> command.
2074
2075C<$max> tells the debugger where the last line of the current file is. It's
2076used to terminate loops most often.
2077
2078=head2 THE COMMAND LOOP
2079
2080Most of C<DB::DB> is actually a command parsing and dispatch loop. It comes
2081in two parts:
2082
2083=over 4
2084
2085=item * The outer part of the loop, starting at the C<CMD> label. This loop
2086reads a command and then executes it.
2087
2088=item * The inner part of the loop, starting at the C<PIPE> label. This part
2089is wholly contained inside the C<CMD> block and only executes a command.
2090Used to handle commands running inside a pager.
2091
2092=back
2093
2094So why have two labels to restart the loop? Because sometimes, it's easier to
2095have a command I<generate> another command and then re-execute the loop to do
2096the new command. This is faster, but perhaps a bit more convoluted.
2097
2098=cut
2099
2100 # The big command dispatch loop. It keeps running until the
2101 # user yields up control again.
2102 #
2103 # If we have a terminal for input, and we get something back
2104 # from readline(), keep on processing.
e22ea7cc
RF
2105 CMD:
2106 while (
2107
69893cff 2108 # We have a terminal, or can get one ...
e22ea7cc
RF
2109 ( $term || &setterm ),
2110
69893cff 2111 # ... and it belogs to this PID or we get one for this PID ...
e22ea7cc
RF
2112 ( $term_pid == $$ or resetterm(1) ),
2113
69893cff 2114 # ... and we got a line of command input ...
e22ea7cc
RF
2115 defined(
2116 $cmd = &readline(
2117 "$pidprompt DB"
2118 . ( '<' x $level )
2119 . ( $#hist + 1 )
2120 . ( '>' x $level ) . " "
69893cff
RGS
2121 )
2122 )
2123 )
2124 {
e22ea7cc 2125
69893cff
RGS
2126 # ... try to execute the input as debugger commands.
2127
2128 # Don't stop running.
2129 $single = 0;
2130
2131 # No signal is active.
2132 $signal = 0;
2133
2134 # Handle continued commands (ending with \):
e22ea7cc
RF
2135 $cmd =~ s/\\$/\n/ && do {
2136 $cmd .= &readline(" cont: ");
2137 redo CMD;
2138 };
69893cff
RGS
2139
2140=head4 The null command
2141
2142A newline entered by itself means "re-execute the last command". We grab the
2143command out of C<$laststep> (where it was recorded previously), and copy it
2144back into C<$cmd> to be executed below. If there wasn't any previous command,
2145we'll do nothing below (no command will match). If there was, we also save it
2146in the command history and fall through to allow the command parsing to pick
2147it up.
2148
2149=cut
2150
2151 # Empty input means repeat the last command.
e22ea7cc
RF
2152 $cmd =~ /^$/ && ( $cmd = $laststep );
2153 chomp($cmd); # get rid of the annoying extra newline
2154 push( @hist, $cmd ) if length($cmd) > 1;
2155 push( @truehist, $cmd );
2156
2157 # This is a restart point for commands that didn't arrive
2158 # via direct user input. It allows us to 'redo PIPE' to
2159 # re-execute command processing without reading a new command.
69893cff 2160 PIPE: {
e22ea7cc
RF
2161 $cmd =~ s/^\s+//s; # trim annoying leading whitespace
2162 $cmd =~ s/\s+$//s; # trim annoying trailing whitespace
2163 ($i) = split( /\s+/, $cmd );
69893cff
RGS
2164
2165=head3 COMMAND ALIASES
2166
2167The debugger can create aliases for commands (these are stored in the
2168C<%alias> hash). Before a command is executed, the command loop looks it up
2169in the alias hash and substitutes the contents of the alias for the command,
2170completely replacing it.
2171
2172=cut
2173
2174 # See if there's an alias for the command, and set it up if so.
e22ea7cc
RF
2175 if ( $alias{$i} ) {
2176
69893cff
RGS
2177 # Squelch signal handling; we want to keep control here
2178 # if something goes loco during the alias eval.
2179 local $SIG{__DIE__};
2180 local $SIG{__WARN__};
2181
2182 # This is a command, so we eval it in the DEBUGGER's
2183 # scope! Otherwise, we can't see the special debugger
2184 # variables, or get to the debugger's subs. (Well, we
2185 # _could_, but why make it even more complicated?)
2186 eval "\$cmd =~ $alias{$i}";
2187 if ($@) {
2188 local $\ = '';
2189 print $OUT "Couldn't evaluate `$i' alias: $@";
2190 next CMD;
2191 }
2192 } ## end if ($alias{$i})
2193
2194=head3 MAIN-LINE COMMANDS
2195
2196All of these commands work up to and after the program being debugged has
2197terminated.
2198
2199=head4 C<q> - quit
2200
2201Quit the debugger. This entails setting the C<$fall_off_end> flag, so we don't
2202try to execute further, cleaning any restart-related stuff out of the
2203environment, and executing with the last value of C<$?>.
2204
2205=cut
2206
2207 $cmd =~ /^q$/ && do {
2208 $fall_off_end = 1;
2209 clean_ENV();
2210 exit $?;
2211 };
2212
2213=head4 C<t> - trace
2214
2215Turn tracing on or off. Inverts the appropriate bit in C<$trace> (q.v.).
2216
2217=cut
2218
e22ea7cc
RF
2219 $cmd =~ /^t$/ && do {
2220 $trace ^= 1;
2221 local $\ = '';
2222 print $OUT "Trace = "
2223 . ( ( $trace & 1 ) ? "on" : "off" ) . "\n";
2224 next CMD;
2225 };
69893cff
RGS
2226
2227=head4 C<S> - list subroutines matching/not matching a pattern
2228
2229Walks through C<%sub>, checking to see whether or not to print the name.
2230
2231=cut
2232
e22ea7cc 2233 $cmd =~ /^S(\s+(!)?(.+))?$/ && do {
69893cff 2234
e22ea7cc 2235 $Srev = defined $2; # Reverse scan?
69893cff
RGS
2236 $Spatt = $3; # The pattern (if any) to use.
2237 $Snocheck = !defined $1; # No args - print all subs.
2238
2239 # Need to make these sane here.
e22ea7cc
RF
2240 local $\ = '';
2241 local $, = '';
69893cff
RGS
2242
2243 # Search through the debugger's magical hash of subs.
2244 # If $nocheck is true, just print the sub name.
2245 # Otherwise, check it against the pattern. We then use
2246 # the XOR trick to reverse the condition as required.
e22ea7cc
RF
2247 foreach $subname ( sort( keys %sub ) ) {
2248 if ( $Snocheck or $Srev ^ ( $subname =~ /$Spatt/ ) ) {
2249 print $OUT $subname, "\n";
2250 }
2251 }
2252 next CMD;
2253 };
69893cff
RGS
2254
2255=head4 C<X> - list variables in current package
2256
2257Since the C<V> command actually processes this, just change this to the
2258appropriate C<V> command and fall through.
2259
2260=cut
2261
e22ea7cc 2262 $cmd =~ s/^X\b/V $package/;
69893cff
RGS
2263
2264=head4 C<V> - list variables
2265
2266Uses C<dumpvar.pl> to dump out the current values for selected variables.
2267
2268=cut
2269
2270 # Bare V commands get the currently-being-debugged package
2271 # added.
e22ea7cc
RF
2272 $cmd =~ /^V$/ && do {
2273 $cmd = "V $package";
2274 };
69893cff
RGS
2275
2276 # V - show variables in package.
2277 $cmd =~ /^V\b\s*(\S+)\s*(.*)/ && do {
e22ea7cc 2278
69893cff
RGS
2279 # Save the currently selected filehandle and
2280 # force output to debugger's filehandle (dumpvar
2281 # just does "print" for output).
e22ea7cc 2282 local ($savout) = select($OUT);
69893cff
RGS
2283
2284 # Grab package name and variables to dump.
e22ea7cc
RF
2285 $packname = $1;
2286 @vars = split( ' ', $2 );
69893cff
RGS
2287
2288 # If main::dumpvar isn't here, get it.
e22ea7cc
RF
2289 do 'dumpvar.pl' unless defined &main::dumpvar;
2290 if ( defined &main::dumpvar ) {
2291
69893cff
RGS
2292 # We got it. Turn off subroutine entry/exit messages
2293 # for the moment, along with return values.
e22ea7cc
RF
2294 local $frame = 0;
2295 local $doret = -2;
69893cff
RGS
2296
2297 # must detect sigpipe failures - not catching
2298 # then will cause the debugger to die.
2299 eval {
2300 &main::dumpvar(
2301 $packname,
2302 defined $option{dumpDepth}
e22ea7cc
RF
2303 ? $option{dumpDepth}
2304 : -1, # assume -1 unless specified
69893cff 2305 @vars
e22ea7cc
RF
2306 );
2307 };
2308
2309 # The die doesn't need to include the $@, because
2310 # it will automatically get propagated for us.
2311 if ($@) {
2312 die unless $@ =~ /dumpvar print failed/;
2313 }
2314 } ## end if (defined &main::dumpvar)
2315 else {
2316
2317 # Couldn't load dumpvar.
2318 print $OUT "dumpvar.pl not available.\n";
2319 }
69893cff 2320
69893cff 2321 # Restore the output filehandle, and go round again.
e22ea7cc
RF
2322 select($savout);
2323 next CMD;
2324 };
69893cff
RGS
2325
2326=head4 C<x> - evaluate and print an expression
2327
2328Hands the expression off to C<DB::eval>, setting it up to print the value
2329via C<dumpvar.pl> instead of just printing it directly.
2330
2331=cut
2332
e22ea7cc
RF
2333 $cmd =~ s/^x\b/ / && do { # Remainder gets done by DB::eval()
2334 $onetimeDump = 'dump'; # main::dumpvar shows the output
69893cff
RGS
2335
2336 # handle special "x 3 blah" syntax XXX propagate
2337 # doc back to special variables.
e22ea7cc
RF
2338 if ( $cmd =~ s/^\s*(\d+)(?=\s)/ / ) {
2339 $onetimedumpDepth = $1;
2340 }
2341 };
69893cff
RGS
2342
2343=head4 C<m> - print methods
2344
2345Just uses C<DB::methods> to determine what methods are available.
2346
2347=cut
2348
e22ea7cc
RF
2349 $cmd =~ s/^m\s+([\w:]+)\s*$/ / && do {
2350 methods($1);
2351 next CMD;
2352 };
69893cff
RGS
2353
2354 # m expr - set up DB::eval to do the work
e22ea7cc
RF
2355 $cmd =~ s/^m\b/ / && do { # Rest gets done by DB::eval()
2356 $onetimeDump = 'methods'; # method output gets used there
2357 };
69893cff
RGS
2358
2359=head4 C<f> - switch files
2360
2361=cut
2362
e22ea7cc
RF
2363 $cmd =~ /^f\b\s*(.*)/ && do {
2364 $file = $1;
2365 $file =~ s/\s+$//;
69893cff
RGS
2366
2367 # help for no arguments (old-style was return from sub).
e22ea7cc
RF
2368 if ( !$file ) {
2369 print $OUT
2370 "The old f command is now the r command.\n"; # hint
2371 print $OUT "The new f command switches filenames.\n";
2372 next CMD;
2373 } ## end if (!$file)
69893cff
RGS
2374
2375 # if not in magic file list, try a close match.
e22ea7cc
RF
2376 if ( !defined $main::{ '_<' . $file } ) {
2377 if ( ($try) = grep( m#^_<.*$file#, keys %main:: ) ) {
2378 {
2379 $try = substr( $try, 2 );
2380 print $OUT "Choosing $try matching `$file':\n";
2381 $file = $try;
2382 }
2383 } ## end if (($try) = grep(m#^_<.*$file#...
2384 } ## end if (!defined $main::{ ...
69893cff
RGS
2385
2386 # If not successfully switched now, we failed.
e22ea7cc
RF
2387 if ( !defined $main::{ '_<' . $file } ) {
2388 print $OUT "No file matching `$file' is loaded.\n";
2389 next CMD;
2390 }
69893cff 2391
e22ea7cc
RF
2392 # We switched, so switch the debugger internals around.
2393 elsif ( $file ne $filename ) {
2394 *dbline = $main::{ '_<' . $file };
2395 $max = $#dbline;
2396 $filename = $file;
2397 $start = 1;
2398 $cmd = "l";
2399 } ## end elsif ($file ne $filename)
2400
2401 # We didn't switch; say we didn't.
2402 else {
2403 print $OUT "Already in $file.\n";
2404 next CMD;
2405 }
2406 };
69893cff
RGS
2407
2408=head4 C<.> - return to last-executed line.
2409
2410We set C<$incr> to -1 to indicate that the debugger shouldn't move ahead,
2411and then we look up the line in the magical C<%dbline> hash.
2412
2413=cut
2414
2415 # . command.
e22ea7cc
RF
2416 $cmd =~ /^\.$/ && do {
2417 $incr = -1; # stay at current line
69893cff
RGS
2418
2419 # Reset everything to the old location.
e22ea7cc
RF
2420 $start = $line;
2421 $filename = $filename_ini;
2422 *dbline = $main::{ '_<' . $filename };
2423 $max = $#dbline;
69893cff
RGS
2424
2425 # Now where are we?
e22ea7cc
RF
2426 print_lineinfo($position);
2427 next CMD;
2428 };
69893cff
RGS
2429
2430=head4 C<-> - back one window
2431
2432We change C<$start> to be one window back; if we go back past the first line,
2433we set it to be the first line. We ser C<$incr> to put us back at the
2434currently-executing line, and then put a C<l $start +> (list one window from
2435C<$start>) in C<$cmd> to be executed later.
2436
2437=cut
2438
2439 # - - back a window.
e22ea7cc
RF
2440 $cmd =~ /^-$/ && do {
2441
69893cff 2442 # back up by a window; go to 1 if back too far.
e22ea7cc
RF
2443 $start -= $incr + $window + 1;
2444 $start = 1 if $start <= 0;
2445 $incr = $window - 1;
69893cff
RGS
2446
2447 # Generate and execute a "l +" command (handled below).
e22ea7cc
RF
2448 $cmd = 'l ' . ($start) . '+';
2449 };
69893cff
RGS
2450
2451=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>, {, {{>
2452
2453In Perl 5.8.0, a realignment of the commands was done to fix up a number of
2454problems, most notably that the default case of several commands destroying
2455the user's work in setting watchpoints, actions, etc. We wanted, however, to
2456retain the old commands for those who were used to using them or who preferred
2457them. At this point, we check for the new commands and call C<cmd_wrapper> to
2458deal with them instead of processing them in-line.
2459
2460=cut
2461
2462 # All of these commands were remapped in perl 5.8.0;
e22ea7cc
RF
2463 # we send them off to the secondary dispatcher (see below).
2464 $cmd =~ /^([aAbBhilLMoOPvwW]\b|[<>\{]{1,2})\s*(.*)/so && do {
2465 &cmd_wrapper( $1, $2, $line );
2466 next CMD;
2467 };
69893cff
RGS
2468
2469=head4 C<y> - List lexicals in higher scope
2470
2471Uses C<PadWalker> to find the lexicals supplied as arguments in a scope
2472above the current one and then displays then using C<dumpvar.pl>.
2473
2474=cut
2475
2476 $cmd =~ /^y(?:\s+(\d*)\s*(.*))?$/ && do {
2477
2478 # See if we've got the necessary support.
2479 eval { require PadWalker; PadWalker->VERSION(0.08) }
2480 or &warn(
2481 $@ =~ /locate/
2482 ? "PadWalker module not found - please install\n"
2483 : $@
2484 )
2485 and next CMD;
2486
2487 # Load up dumpvar if we don't have it. If we can, that is.
2488 do 'dumpvar.pl' unless defined &main::dumpvar;
2489 defined &main::dumpvar
2490 or print $OUT "dumpvar.pl not available.\n"
2491 and next CMD;
2492
2493 # Got all the modules we need. Find them and print them.
e22ea7cc 2494 my @vars = split( ' ', $2 || '' );
69893cff
RGS
2495
2496 # Find the pad.
e22ea7cc 2497 my $h = eval { PadWalker::peek_my( ( $1 || 0 ) + 1 ) };
69893cff
RGS
2498
2499 # Oops. Can't find it.
2500 $@ and $@ =~ s/ at .*//, &warn($@), next CMD;
2501
2502 # Show the desired vars with dumplex().
2503 my $savout = select($OUT);
2504
2505 # Have dumplex dump the lexicals.
e22ea7cc 2506 dumpvar::dumplex( $_, $h->{$_},
69893cff 2507 defined $option{dumpDepth} ? $option{dumpDepth} : -1,
e22ea7cc
RF
2508 @vars )
2509 for sort keys %$h;
69893cff
RGS
2510 select($savout);
2511 next CMD;
2512 };
2513
2514=head3 COMMANDS NOT WORKING AFTER PROGRAM ENDS
2515
2516All of the commands below this point don't work after the program being
2517debugged has ended. All of them check to see if the program has ended; this
2518allows the commands to be relocated without worrying about a 'line of
2519demarcation' above which commands can be entered anytime, and below which
2520they can't.
2521
2522=head4 C<n> - single step, but don't trace down into subs
2523
2524Done by setting C<$single> to 2, which forces subs to execute straight through
2525when entered (see X<DB::sub>). We also save the C<n> command in C<$laststep>,
2526so a null command knows what to re-execute.
2527
2528=cut
2529
e22ea7cc 2530 # n - next
69893cff
RGS
2531 $cmd =~ /^n$/ && do {
2532 end_report(), next CMD if $finished and $level <= 1;
e22ea7cc 2533
69893cff
RGS
2534 # Single step, but don't enter subs.
2535 $single = 2;
e22ea7cc 2536
69893cff 2537 # Save for empty command (repeat last).
e22ea7cc
RF
2538 $laststep = $cmd;
2539 last CMD;
2540 };
69893cff
RGS
2541
2542=head4 C<s> - single-step, entering subs
2543
2544Sets C<$single> to 1, which causes X<DB::sub> to continue tracing inside
2545subs. Also saves C<s> as C<$lastcmd>.
2546
2547=cut
2548
2549 # s - single step.
2550 $cmd =~ /^s$/ && do {
e22ea7cc 2551
69893cff
RGS
2552 # Get out and restart the command loop if program
2553 # has finished.
e22ea7cc
RF
2554 end_report(), next CMD if $finished and $level <= 1;
2555
69893cff 2556 # Single step should enter subs.
e22ea7cc
RF
2557 $single = 1;
2558
69893cff 2559 # Save for empty command (repeat last).
e22ea7cc
RF
2560 $laststep = $cmd;
2561 last CMD;
2562 };
69893cff
RGS
2563
2564=head4 C<c> - run continuously, setting an optional breakpoint
2565
2566Most of the code for this command is taken up with locating the optional
2567breakpoint, which is either a subroutine name or a line number. We set
2568the appropriate one-time-break in C<@dbline> and then turn off single-stepping
2569in this and all call levels above this one.
2570
2571=cut
2572
2573 # c - start continuous execution.
2574 $cmd =~ /^c\b\s*([\w:]*)\s*$/ && do {
e22ea7cc 2575
69893cff
RGS
2576 # Hey, show's over. The debugged program finished
2577 # executing already.
2578 end_report(), next CMD if $finished and $level <= 1;
2579
2580 # Capture the place to put a one-time break.
2581 $subname = $i = $1;
2582
e22ea7cc
RF
2583 # Probably not needed, since we finish an interactive
2584 # sub-session anyway...
2585 # local $filename = $filename;
2586 # local *dbline = *dbline; # XXX Would this work?!
69893cff
RGS
2587 #
2588 # The above question wonders if localizing the alias
2589 # to the magic array works or not. Since it's commented
2590 # out, we'll just leave that to speculation for now.
2591
2592 # If the "subname" isn't all digits, we'll assume it
2593 # is a subroutine name, and try to find it.
e22ea7cc
RF
2594 if ( $subname =~ /\D/ ) { # subroutine name
2595 # Qualify it to the current package unless it's
2596 # already qualified.
69893cff
RGS
2597 $subname = $package . "::" . $subname
2598 unless $subname =~ /::/;
e22ea7cc 2599
69893cff
RGS
2600 # find_sub will return "file:line_number" corresponding
2601 # to where the subroutine is defined; we call find_sub,
e22ea7cc 2602 # break up the return value, and assign it in one
69893cff 2603 # operation.
e22ea7cc 2604 ( $file, $i ) = ( find_sub($subname) =~ /^(.*):(.*)$/ );
69893cff
RGS
2605
2606 # Force the line number to be numeric.
e22ea7cc 2607 $i += 0;
69893cff
RGS
2608
2609 # If we got a line number, we found the sub.
e22ea7cc
RF
2610 if ($i) {
2611
69893cff
RGS
2612 # Switch all the debugger's internals around so
2613 # we're actually working with that file.
e22ea7cc
RF
2614 $filename = $file;
2615 *dbline = $main::{ '_<' . $filename };
2616
69893cff 2617 # Mark that there's a breakpoint in this file.
e22ea7cc
RF
2618 $had_breakpoints{$filename} |= 1;
2619
69893cff
RGS
2620 # Scan forward to the first executable line
2621 # after the 'sub whatever' line.
e22ea7cc
RF
2622 $max = $#dbline;
2623 ++$i while $dbline[$i] == 0 && $i < $max;
2624 } ## end if ($i)
69893cff
RGS
2625
2626 # We didn't find a sub by that name.
e22ea7cc
RF
2627 else {
2628 print $OUT "Subroutine $subname not found.\n";
2629 next CMD;
2630 }
2631 } ## end if ($subname =~ /\D/)
69893cff
RGS
2632
2633 # At this point, either the subname was all digits (an
2634 # absolute line-break request) or we've scanned through
2635 # the code following the definition of the sub, looking
2636 # for an executable, which we may or may not have found.
2637 #
2638 # If $i (which we set $subname from) is non-zero, we
e22ea7cc
RF
2639 # got a request to break at some line somewhere. On
2640 # one hand, if there wasn't any real subroutine name
2641 # involved, this will be a request to break in the current
2642 # file at the specified line, so we have to check to make
69893cff
RGS
2643 # sure that the line specified really is breakable.
2644 #
2645 # On the other hand, if there was a subname supplied, the
2646 # preceeding block has moved us to the proper file and
2647 # location within that file, and then scanned forward
2648 # looking for the next executable line. We have to make
2649 # sure that one was found.
2650 #
2651 # On the gripping hand, we can't do anything unless the
2652 # current value of $i points to a valid breakable line.
2653 # Check that.
e22ea7cc
RF
2654 if ($i) {
2655
69893cff 2656 # Breakable?
e22ea7cc
RF
2657 if ( $dbline[$i] == 0 ) {
2658 print $OUT "Line $i not breakable.\n";
2659 next CMD;
2660 }
2661
69893cff 2662 # Yes. Set up the one-time-break sigil.
e22ea7cc
RF
2663 $dbline{$i} =~ s/($|\0)/;9$1/; # add one-time-only b.p.
2664 } ## end if ($i)
69893cff
RGS
2665
2666 # Turn off stack tracing from here up.
e22ea7cc
RF
2667 for ( $i = 0 ; $i <= $stack_depth ; ) {
2668 $stack[ $i++ ] &= ~1;
2669 }
2670 last CMD;
2671 };
69893cff
RGS
2672
2673=head4 C<r> - return from a subroutine
2674
2675For C<r> to work properly, the debugger has to stop execution again
2676immediately after the return is executed. This is done by forcing
2677single-stepping to be on in the call level above the current one. If
2678we are printing return values when a C<r> is executed, set C<$doret>
2679appropriately, and force us out of the command loop.
2680
2681=cut
2682
2683 # r - return from the current subroutine.
e22ea7cc
RF
2684 $cmd =~ /^r$/ && do {
2685
69893cff 2686 # Can't do anythign if the program's over.
e22ea7cc
RF
2687 end_report(), next CMD if $finished and $level <= 1;
2688
69893cff 2689 # Turn on stack trace.
e22ea7cc
RF
2690 $stack[$stack_depth] |= 1;
2691
69893cff 2692 # Print return value unless the stack is empty.
e22ea7cc
RF
2693 $doret = $option{PrintRet} ? $stack_depth - 1 : -2;
2694 last CMD;
2695 };
69893cff 2696
69893cff
RGS
2697=head4 C<T> - stack trace
2698
2699Just calls C<DB::print_trace>.
2700
2701=cut
2702
e22ea7cc
RF
2703 $cmd =~ /^T$/ && do {
2704 print_trace( $OUT, 1 ); # skip DB
2705 next CMD;
2706 };
69893cff
RGS
2707
2708=head4 C<w> - List window around current line.
2709
2710Just calls C<DB::cmd_w>.
2711
2712=cut
2713
e22ea7cc 2714 $cmd =~ /^w\b\s*(.*)/s && do { &cmd_w( 'w', $1 ); next CMD; };
69893cff
RGS
2715
2716=head4 C<W> - watch-expression processing.
2717
2718Just calls C<DB::cmd_W>.
2719
2720=cut
2721
e22ea7cc 2722 $cmd =~ /^W\b\s*(.*)/s && do { &cmd_W( 'W', $1 ); next CMD; };
69893cff
RGS
2723
2724=head4 C</> - search forward for a string in the source
2725
2726We take the argument and treat it as a pattern. If it turns out to be a
2727bad one, we return the error we got from trying to C<eval> it and exit.
2728If not, we create some code to do the search and C<eval> it so it can't
2729mess us up.
2730
2731=cut
2732
e22ea7cc 2733 $cmd =~ /^\/(.*)$/ && do {
69893cff
RGS
2734
2735 # The pattern as a string.
e22ea7cc 2736 $inpat = $1;
69893cff
RGS
2737
2738 # Remove the final slash.
e22ea7cc 2739 $inpat =~ s:([^\\])/$:$1:;
69893cff
RGS
2740
2741 # If the pattern isn't null ...
e22ea7cc 2742 if ( $inpat ne "" ) {
69893cff
RGS
2743
2744 # Turn of warn and die procesing for a bit.
e22ea7cc
RF
2745 local $SIG{__DIE__};
2746 local $SIG{__WARN__};
69893cff
RGS
2747
2748 # Create the pattern.
e22ea7cc
RF
2749 eval '$inpat =~ m' . "\a$inpat\a";
2750 if ( $@ ne "" ) {
2751
69893cff 2752 # Oops. Bad pattern. No biscuit.
e22ea7cc 2753 # Print the eval error and go back for more
69893cff 2754 # commands.
e22ea7cc
RF
2755 print $OUT "$@";
2756 next CMD;
2757 }
2758 $pat = $inpat;
2759 } ## end if ($inpat ne "")
69893cff
RGS
2760
2761 # Set up to stop on wrap-around.
e22ea7cc 2762 $end = $start;
69893cff
RGS
2763
2764 # Don't move off the current line.
e22ea7cc 2765 $incr = -1;
69893cff
RGS
2766
2767 # Done in eval so nothing breaks if the pattern
2768 # does something weird.
e22ea7cc
RF
2769 eval '
2770 for (;;) {
69893cff 2771 # Move ahead one line.
e22ea7cc 2772 ++$start;
69893cff
RGS
2773
2774 # Wrap if we pass the last line.
e22ea7cc 2775 $start = 1 if ($start > $max);
69893cff
RGS
2776
2777 # Stop if we have gotten back to this line again,
e22ea7cc 2778 last if ($start == $end);
69893cff
RGS
2779
2780 # A hit! (Note, though, that we are doing
2781 # case-insensitive matching. Maybe a qr//
2782 # expression would be better, so the user could
2783 # do case-sensitive matching if desired.
e22ea7cc
RF
2784 if ($dbline[$start] =~ m' . "\a$pat\a" . 'i) {
2785 if ($slave_editor) {
69893cff 2786 # Handle proper escaping in the slave.
e22ea7cc
RF
2787 print $OUT "\032\032$filename:$start:0\n";
2788 }
2789 else {
69893cff 2790 # Just print the line normally.
e22ea7cc
RF
2791 print $OUT "$start:\t",$dbline[$start],"\n";
2792 }
69893cff 2793 # And quit since we found something.
e22ea7cc
RF
2794 last;
2795 }
2796 } ';
2797
69893cff 2798 # If we wrapped, there never was a match.
e22ea7cc
RF
2799 print $OUT "/$pat/: not found\n" if ( $start == $end );
2800 next CMD;
2801 };
69893cff
RGS
2802
2803=head4 C<?> - search backward for a string in the source
2804
2805Same as for C</>, except the loop runs backwards.
2806
2807=cut
2808
2809 # ? - backward pattern search.
e22ea7cc 2810 $cmd =~ /^\?(.*)$/ && do {
69893cff
RGS
2811
2812 # Get the pattern, remove trailing question mark.
e22ea7cc
RF
2813 $inpat = $1;
2814 $inpat =~ s:([^\\])\?$:$1:;
69893cff
RGS
2815
2816 # If we've got one ...
e22ea7cc 2817 if ( $inpat ne "" ) {
69893cff
RGS
2818
2819 # Turn off die & warn handlers.
e22ea7cc
RF
2820 local $SIG{__DIE__};
2821 local $SIG{__WARN__};
2822 eval '$inpat =~ m' . "\a$inpat\a";
2823
2824 if ( $@ ne "" ) {
2825
69893cff 2826 # Ouch. Not good. Print the error.
e22ea7cc
RF
2827 print $OUT $@;
2828 next CMD;
2829 }
2830 $pat = $inpat;
69893cff 2831 } ## end if ($inpat ne "")
e22ea7cc 2832
69893cff 2833 # Where we are now is where to stop after wraparound.
e22ea7cc 2834 $end = $start;
69893cff
RGS
2835
2836 # Don't move away from this line.
e22ea7cc 2837 $incr = -1;
69893cff
RGS
2838
2839 # Search inside the eval to prevent pattern badness
2840 # from killing us.
e22ea7cc
RF
2841 eval '
2842 for (;;) {
69893cff 2843 # Back up a line.
e22ea7cc 2844 --$start;
69893cff
RGS
2845
2846 # Wrap if we pass the first line.
e22ea7cc
RF
2847
2848 $start = $max if ($start <= 0);
69893cff
RGS
2849
2850 # Quit if we get back where we started,
e22ea7cc 2851 last if ($start == $end);
69893cff
RGS
2852
2853 # Match?
e22ea7cc
RF
2854 if ($dbline[$start] =~ m' . "\a$pat\a" . 'i) {
2855 if ($slave_editor) {
69893cff 2856 # Yep, follow slave editor requirements.
e22ea7cc
RF
2857 print $OUT "\032\032$filename:$start:0\n";
2858 }
2859 else {
69893cff 2860 # Yep, just print normally.
e22ea7cc
RF
2861 print $OUT "$start:\t",$dbline[$start],"\n";
2862 }
69893cff
RGS
2863
2864 # Found, so done.
e22ea7cc
RF
2865 last;
2866 }
2867 } ';
2868
2869 # Say we failed if the loop never found anything,
2870 print $OUT "?$pat?: not found\n" if ( $start == $end );
2871 next CMD;
2872 };
69893cff
RGS
2873
2874=head4 C<$rc> - Recall command
2875
2876Manages the commands in C<@hist> (which is created if C<Term::ReadLine> reports
2877that the terminal supports history). It find the the command required, puts it
2878into C<$cmd>, and redoes the loop to execute it.
2879
2880=cut
2881
e22ea7cc
RF
2882 # $rc - recall command.
2883 $cmd =~ /^$rc+\s*(-)?(\d+)?$/ && do {
69893cff
RGS
2884
2885 # No arguments, take one thing off history.
e22ea7cc 2886 pop(@hist) if length($cmd) > 1;
69893cff 2887
e22ea7cc 2888 # Relative (- found)?
69893cff 2889 # Y - index back from most recent (by 1 if bare minus)
e22ea7cc 2890 # N - go to that particular command slot or the last
69893cff 2891 # thing if nothing following.
e22ea7cc 2892 $i = $1 ? ( $#hist - ( $2 || 1 ) ) : ( $2 || $#hist );
69893cff
RGS
2893
2894 # Pick out the command desired.
e22ea7cc 2895 $cmd = $hist[$i];
69893cff
RGS
2896
2897 # Print the command to be executed and restart the loop
2898 # with that command in the buffer.
e22ea7cc
RF
2899 print $OUT $cmd, "\n";
2900 redo CMD;
2901 };
69893cff
RGS
2902
2903=head4 C<$sh$sh> - C<system()> command
2904
2905Calls the C<DB::system()> to handle the command. This keeps the C<STDIN> and
2906C<STDOUT> from getting messed up.
2907
2908=cut
2909
2910 # $sh$sh - run a shell command (if it's all ASCII).
2911 # Can't run shell commands with Unicode in the debugger, hmm.
e22ea7cc
RF
2912 $cmd =~ /^$sh$sh\s*([\x00-\xff]*)/ && do {
2913
69893cff 2914 # System it.
e22ea7cc
RF
2915 &system($1);
2916 next CMD;
2917 };
69893cff
RGS
2918
2919=head4 C<$rc I<pattern> $rc> - Search command history
2920
2921Another command to manipulate C<@hist>: this one searches it with a pattern.
2922If a command is found, it is placed in C<$cmd> and executed via <redo>.
2923
2924=cut
2925
e22ea7cc
RF
2926 # $rc pattern $rc - find a command in the history.
2927 $cmd =~ /^$rc([^$rc].*)$/ && do {
2928
69893cff 2929 # Create the pattern to use.
e22ea7cc 2930 $pat = "^$1";
69893cff
RGS
2931
2932 # Toss off last entry if length is >1 (and it always is).
e22ea7cc 2933 pop(@hist) if length($cmd) > 1;
69893cff
RGS
2934
2935 # Look backward through the history.
e22ea7cc
RF
2936 for ( $i = $#hist ; $i ; --$i ) {
2937
69893cff 2938 # Stop if we find it.
e22ea7cc
RF
2939 last if $hist[$i] =~ /$pat/;
2940 }
2941
2942 if ( !$i ) {
69893cff 2943
69893cff 2944 # Never found it.
e22ea7cc
RF
2945 print $OUT "No such command!\n\n";
2946 next CMD;
2947 }
69893cff
RGS
2948
2949 # Found it. Put it in the buffer, print it, and process it.
e22ea7cc
RF
2950 $cmd = $hist[$i];
2951 print $OUT $cmd, "\n";
2952 redo CMD;
2953 };
69893cff
RGS
2954
2955=head4 C<$sh> - Invoke a shell
2956
2957Uses C<DB::system> to invoke a shell.
2958
2959=cut
2960
2961 # $sh - start a shell.
e22ea7cc
RF
2962 $cmd =~ /^$sh$/ && do {
2963
69893cff
RGS
2964 # Run the user's shell. If none defined, run Bourne.
2965 # We resume execution when the shell terminates.
e22ea7cc
RF
2966 &system( $ENV{SHELL} || "/bin/sh" );
2967 next CMD;
2968 };
69893cff
RGS
2969
2970=head4 C<$sh I<command>> - Force execution of a command in a shell
2971
2972Like the above, but the command is passed to the shell. Again, we use
2973C<DB::system> to avoid problems with C<STDIN> and C<STDOUT>.
2974
2975=cut
2976
2977 # $sh command - start a shell and run a command in it.
e22ea7cc
RF
2978 $cmd =~ /^$sh\s*([\x00-\xff]*)/ && do {
2979
2980 # XXX: using csh or tcsh destroys sigint retvals!
2981 #&system($1); # use this instead
69893cff
RGS
2982
2983 # use the user's shell, or Bourne if none defined.
e22ea7cc
RF
2984 &system( $ENV{SHELL} || "/bin/sh", "-c", $1 );
2985 next CMD;
2986 };
69893cff
RGS
2987
2988=head4 C<H> - display commands in history
2989
2990Prints the contents of C<@hist> (if any).
2991
2992=cut
2993
7fddc82f
RF
2994 $cmd =~ /^H\b\s*\*/ && do {
2995 @hist = @truehist = ();
2996 print $OUT "History cleansed\n";
2997 next CMD;
2998 };
e22ea7cc
RF
2999
3000 $cmd =~ /^H\b\s*(-(\d+))?/ && do {
3001
3002 # Anything other than negative numbers is ignored by
69893cff 3003 # the (incorrect) pattern, so this test does nothing.
e22ea7cc 3004 $end = $2 ? ( $#hist - $2 ) : 0;
69893cff
RGS
3005
3006 # Set to the minimum if less than zero.
e22ea7cc 3007 $hist = 0 if $hist < 0;
69893cff 3008
e22ea7cc 3009 # Start at the end of the array.
69893cff
RGS
3010 # Stay in while we're still above the ending value.
3011 # Tick back by one each time around the loop.
e22ea7cc 3012 for ( $i = $#hist ; $i > $end ; $i-- ) {
69893cff
RGS
3013
3014 # Print the command unless it has no arguments.
e22ea7cc
RF
3015 print $OUT "$i: ", $hist[$i], "\n"
3016 unless $hist[$i] =~ /^.?$/;
3017 }
3018 next CMD;
3019 };
69893cff
RGS
3020
3021=head4 C<man, doc, perldoc> - look up documentation
3022
3023Just calls C<runman()> to print the appropriate document.
3024
3025=cut
3026
e22ea7cc
RF
3027 # man, perldoc, doc - show manual pages.
3028 $cmd =~ /^(?:man|(?:perl)?doc)\b(?:\s+([^(]*))?$/ && do {
3029 runman($1);
3030 next CMD;
3031 };
69893cff
RGS
3032
3033=head4 C<p> - print
3034
3035Builds a C<print EXPR> expression in the C<$cmd>; this will get executed at
3036the bottom of the loop.
3037
3038=cut
3039
3040 # p - print (no args): print $_.
e22ea7cc 3041 $cmd =~ s/^p$/print {\$DB::OUT} \$_/;
69893cff
RGS
3042
3043 # p - print the given expression.
e22ea7cc 3044 $cmd =~ s/^p\b/print {\$DB::OUT} /;
69893cff
RGS
3045
3046=head4 C<=> - define command alias
3047
3048Manipulates C<%alias> to add or list command aliases.
3049
3050=cut
3051
e22ea7cc
RF
3052 # = - set up a command alias.
3053 $cmd =~ s/^=\s*// && do {
3054 my @keys;
3055 if ( length $cmd == 0 ) {
3056
69893cff 3057 # No args, get current aliases.
e22ea7cc
RF
3058 @keys = sort keys %alias;
3059 }
3060 elsif ( my ( $k, $v ) = ( $cmd =~ /^(\S+)\s+(\S.*)/ ) ) {
3061
69893cff
RGS
3062 # Creating a new alias. $k is alias name, $v is
3063 # alias value.
3064
e22ea7cc
RF
3065 # can't use $_ or kill //g state
3066 for my $x ( $k, $v ) {
3067
3068 # Escape "alarm" characters.
3069 $x =~ s/\a/\\a/g;
3070 }
69893cff
RGS
3071
3072 # Substitute key for value, using alarm chars
e22ea7cc 3073 # as separators (which is why we escaped them in
69893cff 3074 # the command).
e22ea7cc 3075 $alias{$k} = "s\a$k\a$v\a";
69893cff
RGS
3076
3077 # Turn off standard warn and die behavior.
e22ea7cc
RF
3078 local $SIG{__DIE__};
3079 local $SIG{__WARN__};
69893cff
RGS
3080
3081 # Is it valid Perl?
e22ea7cc
RF
3082 unless ( eval "sub { s\a$k\a$v\a }; 1" ) {
3083
69893cff 3084 # Nope. Bad alias. Say so and get out.
e22ea7cc
RF
3085 print $OUT "Can't alias $k to $v: $@\n";
3086 delete $alias{$k};
3087 next CMD;
3088 }
3089
69893cff 3090 # We'll only list the new one.
e22ea7cc 3091 @keys = ($k);
69893cff
RGS
3092 } ## end elsif (my ($k, $v) = ($cmd...
3093
3094 # The argument is the alias to list.
e22ea7cc
RF
3095 else {
3096 @keys = ($cmd);
3097 }
69893cff
RGS
3098
3099 # List aliases.
e22ea7cc
RF
3100 for my $k (@keys) {
3101
69893cff
RGS
3102 # Messy metaquoting: Trim the substiution code off.
3103 # We use control-G as the delimiter because it's not
3104 # likely to appear in the alias.
e22ea7cc
RF
3105 if ( ( my $v = $alias{$k} ) =~ s\as\a$k\a(.*)\a$\a1\a ) {
3106
69893cff 3107 # Print the alias.
e22ea7cc
RF
3108 print $OUT "$k\t= $1\n";
3109 }
3110 elsif ( defined $alias{$k} ) {
3111
69893cff 3112 # Couldn't trim it off; just print the alias code.
e22ea7cc
RF
3113 print $OUT "$k\t$alias{$k}\n";
3114 }
3115 else {
3116
69893cff 3117 # No such, dude.
e22ea7cc
RF
3118 print "No alias for $k\n";
3119 }
69893cff 3120 } ## end for my $k (@keys)
e22ea7cc
RF
3121 next CMD;
3122 };
69893cff
RGS
3123
3124=head4 C<source> - read commands from a file.
3125
3126Opens a lexical filehandle and stacks it on C<@cmdfhs>; C<DB::readline> will
3127pick it up.
3128
3129=cut
3130
e22ea7cc
RF
3131 # source - read commands from a file (or pipe!) and execute.
3132 $cmd =~ /^source\s+(.*\S)/ && do {
3133 if ( open my $fh, $1 ) {
3134
69893cff 3135 # Opened OK; stick it in the list of file handles.
e22ea7cc
RF
3136 push @cmdfhs, $fh;
3137 }
3138 else {
3139
3140 # Couldn't open it.
3141 &warn("Can't execute `$1': $!\n");
3142 }
3143 next CMD;
3144 };
69893cff
RGS
3145
3146=head4 C<save> - send current history to a file
3147
3148Takes the complete history, (not the shrunken version you see with C<H>),
3149and saves it to the given filename, so it can be replayed using C<source>.
3150
3151Note that all C<^(save|source)>'s are commented out with a view to minimise recursion.
3152
3153=cut
3154
3155 # save source - write commands to a file for later use
3156 $cmd =~ /^save\s*(.*)$/ && do {
e22ea7cc
RF
3157 my $file = $1 || '.perl5dbrc'; # default?
3158 if ( open my $fh, "> $file" ) {
3159
3160 # chomp to remove extraneous newlines from source'd files
3161 chomp( my @truelist =
3162 map { m/^\s*(save|source)/ ? "#$_" : $_ }
3163 @truehist );
3164 print $fh join( "\n", @truelist );
69893cff 3165 print "commands saved in $file\n";
e22ea7cc
RF
3166 }
3167 else {
69893cff
RGS
3168 &warn("Can't save debugger commands in '$1': $!\n");
3169 }
3170 next CMD;
3171 };
3172
7fddc82f
RF
3173=head4 C<R> - restart
3174
3175Restart the debugger session.
3176
3177=head4 C<rerun> - rerun the current session
3178
3179Return to any given position in the B<true>-history list
3180
3181=cut
3182
3183 # R - restart execution.
3184 # rerun - controlled restart execution.
3185 $cmd =~ /^(R|rerun\s*(.*))$/ && do {
3186 my @args = ($1 eq 'R' ? restart() : rerun($2));
3187
3188 # And run Perl again. We use exec() to keep the
3189 # PID stable (and that way $ini_pids is still valid).
3190 exec(@args) || print $OUT "exec failed: $!\n";
3191
3192 last CMD;
3193 };
3194
69893cff
RGS
3195=head4 C<|, ||> - pipe output through the pager.
3196
3197FOR C<|>, we save C<OUT> (the debugger's output filehandle) and C<STDOUT>
3198(the program's standard output). For C<||>, we only save C<OUT>. We open a
3199pipe to the pager (restoring the output filehandles if this fails). If this
3200is the C<|> command, we also set up a C<SIGPIPE> handler which will simply
3201set C<$signal>, sending us back into the debugger.
3202
3203We then trim off the pipe symbols and C<redo> the command loop at the
3204C<PIPE> label, causing us to evaluate the command in C<$cmd> without
3205reading another.
3206
3207=cut
3208
3209 # || - run command in the pager, with output to DB::OUT.
e22ea7cc
RF
3210 $cmd =~ /^\|\|?\s*[^|]/ && do {
3211 if ( $pager =~ /^\|/ ) {
3212
69893cff 3213 # Default pager is into a pipe. Redirect I/O.
e22ea7cc
RF
3214 open( SAVEOUT, ">&STDOUT" )
3215 || &warn("Can't save STDOUT");
3216 open( STDOUT, ">&OUT" )
3217 || &warn("Can't redirect STDOUT");
69893cff 3218 } ## end if ($pager =~ /^\|/)
e22ea7cc
RF
3219 else {
3220
69893cff 3221 # Not into a pipe. STDOUT is safe.
e22ea7cc
RF
3222 open( SAVEOUT, ">&OUT" ) || &warn("Can't save DB::OUT");
3223 }
69893cff
RGS
3224
3225 # Fix up environment to record we have less if so.
e22ea7cc
RF
3226 fix_less();
3227
3228 unless ( $piped = open( OUT, $pager ) ) {
69893cff 3229
69893cff 3230 # Couldn't open pipe to pager.
e22ea7cc
RF
3231 &warn("Can't pipe output to `$pager'");
3232 if ( $pager =~ /^\|/ ) {
3233
69893cff 3234 # Redirect I/O back again.
e22ea7cc
RF
3235 open( OUT, ">&STDOUT" ) # XXX: lost message
3236 || &warn("Can't restore DB::OUT");
3237 open( STDOUT, ">&SAVEOUT" )
3238 || &warn("Can't restore STDOUT");
3239 close(SAVEOUT);
69893cff 3240 } ## end if ($pager =~ /^\|/)
e22ea7cc
RF
3241 else {
3242
69893cff 3243 # Redirect I/O. STDOUT already safe.
e22ea7cc
RF
3244 open( OUT, ">&STDOUT" ) # XXX: lost message
3245 || &warn("Can't restore DB::OUT");
3246 }
3247 next CMD;
69893cff
RGS
3248 } ## end unless ($piped = open(OUT,...
3249
3250 # Set up broken-pipe handler if necessary.
e22ea7cc
RF
3251 $SIG{PIPE} = \&DB::catch
3252 if $pager =~ /^\|/
3253 && ( "" eq $SIG{PIPE} || "DEFAULT" eq $SIG{PIPE} );
69893cff
RGS
3254
3255 # Save current filehandle, unbuffer out, and put it back.
e22ea7cc
RF
3256 $selected = select(OUT);
3257 $| = 1;
69893cff
RGS
3258
3259 # Don't put it back if pager was a pipe.
e22ea7cc 3260 select($selected), $selected = "" unless $cmd =~ /^\|\|/;
69893cff
RGS
3261
3262 # Trim off the pipe symbols and run the command now.
e22ea7cc
RF
3263 $cmd =~ s/^\|+\s*//;
3264 redo PIPE;
3265 };
69893cff
RGS
3266
3267=head3 END OF COMMAND PARSING
3268
3269Anything left in C<$cmd> at this point is a Perl expression that we want to
3270evaluate. We'll always evaluate in the user's context, and fully qualify
3271any variables we might want to address in the C<DB> package.
3272
3273=cut
3274
3275 # t - turn trace on.
e22ea7cc 3276 $cmd =~ s/^t\s/\$DB::trace |= 1;\n/;
69893cff
RGS
3277
3278 # s - single-step. Remember the last command was 's'.
e22ea7cc 3279 $cmd =~ s/^s\s/\$DB::single = 1;\n/ && do { $laststep = 's' };
69893cff
RGS
3280
3281 # n - single-step, but not into subs. Remember last command
e22ea7cc
RF
3282 # was 'n'.
3283 $cmd =~ s/^n\s/\$DB::single = 2;\n/ && do { $laststep = 'n' };
69893cff 3284
e22ea7cc 3285 } # PIPE:
69893cff 3286
e22ea7cc 3287 # Make sure the flag that says "the debugger's running" is
69893cff 3288 # still on, to make sure we get control again.
e22ea7cc 3289 $evalarg = "\$^D = \$^D | \$DB::db_stop;\n$cmd";
69893cff
RGS
3290
3291 # Run *our* eval that executes in the caller's context.
e22ea7cc 3292 &eval;
69893cff
RGS
3293
3294 # Turn off the one-time-dump stuff now.
e22ea7cc
RF
3295 if ($onetimeDump) {
3296 $onetimeDump = undef;
69893cff 3297 $onetimedumpDepth = undef;
e22ea7cc
RF
3298 }
3299 elsif ( $term_pid == $$ ) {
3300 STDOUT->flush();
3301 STDERR->flush();
3302
69893cff 3303 # XXX If this is the master pid, print a newline.
e22ea7cc
RF
3304 print $OUT "\n";
3305 }
3306 } ## end while (($term || &setterm...
69893cff
RGS
3307
3308=head3 POST-COMMAND PROCESSING
3309
3310After each command, we check to see if the command output was piped anywhere.
3311If so, we go through the necessary code to unhook the pipe and go back to
3312our standard filehandles for input and output.
3313
3314=cut
3315
e22ea7cc 3316 continue { # CMD:
69893cff
RGS
3317
3318 # At the end of every command:
e22ea7cc
RF
3319 if ($piped) {
3320
69893cff 3321 # Unhook the pipe mechanism now.
e22ea7cc
RF
3322 if ( $pager =~ /^\|/ ) {
3323
69893cff 3324 # No error from the child.
e22ea7cc 3325 $? = 0;
69893cff 3326
e22ea7cc
RF
3327 # we cannot warn here: the handle is missing --tchrist
3328 close(OUT) || print SAVEOUT "\nCan't close DB::OUT\n";
69893cff 3329
e22ea7cc 3330 # most of the $? crud was coping with broken cshisms
69893cff 3331 # $? is explicitly set to 0, so this never runs.
e22ea7cc
RF
3332 if ($?) {
3333 print SAVEOUT "Pager `$pager' failed: ";
3334 if ( $? == -1 ) {
3335 print SAVEOUT "shell returned -1\n";
3336 }
3337 elsif ( $? >> 8 ) {
3338 print SAVEOUT ( $? & 127 )
3339 ? " (SIG#" . ( $? & 127 ) . ")"
3340 : "", ( $? & 128 ) ? " -- core dumped" : "", "\n";
3341 }
3342 else {
3343 print SAVEOUT "status ", ( $? >> 8 ), "\n";
3344 }
69893cff
RGS
3345 } ## end if ($?)
3346
e22ea7cc 3347 # Reopen filehandle for our output (if we can) and
69893cff 3348 # restore STDOUT (if we can).
e22ea7cc
RF
3349 open( OUT, ">&STDOUT" ) || &warn("Can't restore DB::OUT");
3350 open( STDOUT, ">&SAVEOUT" )
3351 || &warn("Can't restore STDOUT");
69893cff
RGS
3352
3353 # Turn off pipe exception handler if necessary.
e22ea7cc 3354 $SIG{PIPE} = "DEFAULT" if $SIG{PIPE} eq \&DB::catch;
69893cff 3355
e22ea7cc
RF
3356 # Will stop ignoring SIGPIPE if done like nohup(1)
3357 # does SIGINT but Perl doesn't give us a choice.
69893cff 3358 } ## end if ($pager =~ /^\|/)
e22ea7cc
RF
3359 else {
3360
69893cff 3361 # Non-piped "pager". Just restore STDOUT.
e22ea7cc
RF
3362 open( OUT, ">&SAVEOUT" ) || &warn("Can't restore DB::OUT");
3363 }
69893cff
RGS
3364
3365 # Close filehandle pager was using, restore the normal one
3366 # if necessary,
3367 close(SAVEOUT);
e22ea7cc 3368 select($selected), $selected = "" unless $selected eq "";
69893cff
RGS
3369
3370 # No pipes now.
e22ea7cc 3371 $piped = "";
69893cff 3372 } ## end if ($piped)
e22ea7cc 3373 } # CMD:
69893cff
RGS
3374
3375=head3 COMMAND LOOP TERMINATION
3376
3377When commands have finished executing, we come here. If the user closed the
3378input filehandle, we turn on C<$fall_off_end> to emulate a C<q> command. We
3379evaluate any post-prompt items. We restore C<$@>, C<$!>, C<$^E>, C<$,>, C<$/>,
3380C<$\>, and C<$^W>, and return a null list as expected by the Perl interpreter.
3381The interpreter will then execute the next line and then return control to us
3382again.
3383
3384=cut
3385
3386 # No more commands? Quit.
e22ea7cc 3387 $fall_off_end = 1 unless defined $cmd; # Emulate `q' on EOF
69893cff
RGS
3388
3389 # Evaluate post-prompt commands.
e22ea7cc
RF
3390 foreach $evalarg (@$post) {
3391 &eval;
3392 }
3393 } # if ($single || $signal)
69893cff
RGS
3394
3395 # Put the user's globals back where you found them.
e22ea7cc 3396 ( $@, $!, $^E, $,, $/, $\, $^W ) = @saved;
69893cff
RGS
3397 ();
3398} ## end sub DB
3399
3400# The following code may be executed now:
3401# BEGIN {warn 4}
3402
3403=head2 sub
3404
3405C<sub> is called whenever a subroutine call happens in the program being
3406debugged. The variable C<$DB::sub> contains the name of the subroutine
3407being called.
3408
3409The core function of this subroutine is to actually call the sub in the proper
3410context, capturing its output. This of course causes C<DB::DB> to get called
3411again, repeating until the subroutine ends and returns control to C<DB::sub>
3412again. Once control returns, C<DB::sub> figures out whether or not to dump the
3413return value, and returns its captured copy of the return value as its own
3414return value. The value then feeds back into the program being debugged as if
3415C<DB::sub> hadn't been there at all.
3416
3417C<sub> does all the work of printing the subroutine entry and exit messages
3418enabled by setting C<$frame>. It notes what sub the autoloader got called for,
3419and also prints the return value if needed (for the C<r> command and if
3420the 16 bit is set in C<$frame>).
3421
3422It also tracks the subroutine call depth by saving the current setting of
3423C<$single> in the C<@stack> package global; if this exceeds the value in
3424C<$deep>, C<sub> automatically turns on printing of the current depth by
3425setting the 4 bit in C<$single>. In any case, it keeps the current setting
3426of stop/don't stop on entry to subs set as it currently is set.
3427
3428=head3 C<caller()> support
3429
3430If C<caller()> is called from the package C<DB>, it provides some
3431additional data, in the following order:
3432
3433=over 4
3434
3435=item * C<$package>
3436
3437The package name the sub was in
3438
3439=item * C<$filename>
3440
3441The filename it was defined in
3442
3443=item * C<$line>
3444
3445The line number it was defined on
3446
3447=item * C<$subroutine>
3448
3449The subroutine name; C<'(eval)'> if an C<eval>().
3450
3451=item * C<$hasargs>
3452
34531 if it has arguments, 0 if not
3454
3455=item * C<$wantarray>
3456
34571 if array context, 0 if scalar context
3458
3459=item * C<$evaltext>
3460
3461The C<eval>() text, if any (undefined for C<eval BLOCK>)
3462
3463=item * C<$is_require>
3464
3465frame was created by a C<use> or C<require> statement
3466
3467=item * C<$hints>
3468
3469pragma information; subject to change between versions
3470
3471=item * C<$bitmask>
3472
3473pragma information: subject to change between versions
3474
3475=item * C<@DB::args>
3476
3477arguments with which the subroutine was invoked
3478
3479=back
3480
3481=cut
d338d6fe 3482
d12a4851 3483sub sub {
69893cff
RGS
3484
3485 # Whether or not the autoloader was running, a scalar to put the
3486 # sub's return value in (if needed), and an array to put the sub's
3487 # return value in (if needed).
e22ea7cc 3488 my ( $al, $ret, @ret ) = "";
69893cff
RGS
3489
3490 # If the last ten characters are C'::AUTOLOAD', note we've traced
3491 # into AUTOLOAD for $sub.
e22ea7cc
RF
3492 if ( length($sub) > 10 && substr( $sub, -10, 10 ) eq '::AUTOLOAD' ) {
3493 $al = " for $$sub";
d12a4851 3494 }
69893cff
RGS
3495
3496 # We stack the stack pointer and then increment it to protect us
3497 # from a situation that might unwind a whole bunch of call frames
3498 # at once. Localizing the stack pointer means that it will automatically
3499 # unwind the same amount when multiple stack frames are unwound.
e22ea7cc 3500 local $stack_depth = $stack_depth + 1; # Protect from non-local exits
69893cff
RGS
3501
3502 # Expand @stack.
d12a4851 3503 $#stack = $stack_depth;
69893cff
RGS
3504
3505 # Save current single-step setting.
d12a4851 3506 $stack[-1] = $single;
69893cff 3507
e22ea7cc 3508 # Turn off all flags except single-stepping.
d12a4851 3509 $single &= 1;
69893cff
RGS
3510
3511 # If we've gotten really deeply recursed, turn on the flag that will
3512 # make us stop with the 'deep recursion' message.
d12a4851 3513 $single |= 4 if $stack_depth == $deep;
69893cff
RGS
3514
3515 # If frame messages are on ...
3516 (
3517 $frame & 4 # Extended frame entry message
e22ea7cc
RF
3518 ? (
3519 print_lineinfo( ' ' x ( $stack_depth - 1 ), "in " ),
69893cff 3520
e22ea7cc 3521 # Why -1? But it works! :-(
69893cff
RGS
3522 # Because print_trace will call add 1 to it and then call
3523 # dump_trace; this results in our skipping -1+1 = 0 stack frames
3524 # in dump_trace.
e22ea7cc
RF
3525 print_trace( $LINEINFO, -1, 1, 1, "$sub$al" )
3526 )
3527 : print_lineinfo( ' ' x ( $stack_depth - 1 ), "entering $sub$al\n" )
3528
69893cff 3529 # standard frame entry message
e22ea7cc
RF
3530 )
3531 if $frame;
69893cff
RGS
3532
3533 # Determine the sub's return type,and capture approppriately.
d12a4851 3534 if (wantarray) {
e22ea7cc 3535
69893cff
RGS
3536 # Called in array context. call sub and capture output.
3537 # DB::DB will recursively get control again if appropriate; we'll come
3538 # back here when the sub is finished.
d12a4851 3539 if ($assertion) {
e22ea7cc
RF
3540 $assertion = 0;
3541 eval { @ret = &$sub; };
3542 if ($@) {
3543 print $OUT $@;
3544 $signal = 1 unless $warnassertions;
3545 }
3546 }
3547 else {
69893cff 3548 @ret = &$sub;
69893cff 3549 }
69893cff
RGS
3550
3551 # Pop the single-step value back off the stack.
e22ea7cc 3552 $single |= $stack[ $stack_depth-- ];
69893cff
RGS
3553
3554 # Check for exit trace messages...
e22ea7cc
RF
3555 (
3556 $frame & 4 # Extended exit message
3557 ? (
3558 print_lineinfo( ' ' x $stack_depth, "out " ),
3559 print_trace( $LINEINFO, -1, 1, 1, "$sub$al" )
3560 )
3561 : print_lineinfo( ' ' x $stack_depth, "exited $sub$al\n" )
3562
69893cff 3563 # Standard exit message
e22ea7cc
RF
3564 )
3565 if $frame & 2;
69893cff
RGS
3566
3567 # Print the return info if we need to.
e22ea7cc
RF
3568 if ( $doret eq $stack_depth or $frame & 16 ) {
3569
69893cff 3570 # Turn off output record separator.
e22ea7cc
RF
3571 local $\ = '';
3572 my $fh = ( $doret eq $stack_depth ? $OUT : $LINEINFO );
69893cff
RGS
3573
3574 # Indent if we're printing because of $frame tracing.
e22ea7cc 3575 print $fh ' ' x $stack_depth if $frame & 16;
69893cff
RGS
3576
3577 # Print the return value.
e22ea7cc
RF
3578 print $fh "list context return from $sub:\n";
3579 dumpit( $fh, \@ret );
69893cff
RGS
3580
3581 # And don't print it again.
e22ea7cc 3582 $doret = -2;
69893cff 3583 } ## end if ($doret eq $stack_depth...
e22ea7cc
RF
3584 # And we have to return the return value now.
3585 @ret;
69893cff
RGS
3586 } ## end if (wantarray)
3587
3588 # Scalar context.
3589 else {
d12a4851 3590 if ($assertion) {
e22ea7cc
RF
3591 $assertion = 0;
3592 eval {
3593
3594 # Save the value if it's wanted at all.
3595 $ret = &$sub;
3596 };
3597 if ($@) {
3598 print $OUT $@;
3599 $signal = 1 unless $warnassertions;
3600 }
3601 $ret = undef unless defined wantarray;
69893cff 3602 }
69893cff 3603 else {
e22ea7cc
RF
3604 if ( defined wantarray ) {
3605
3606 # Save the value if it's wanted at all.
3607 $ret = &$sub;
3608 }
3609 else {
3610
3611 # Void return, explicitly.
3612 &$sub;
3613 undef $ret;
3614 }
3615 } # if assertion
69893cff
RGS
3616
3617 # Pop the single-step value off the stack.
e22ea7cc 3618 $single |= $stack[ $stack_depth-- ];
69893cff
RGS
3619
3620 # If we're doing exit messages...
e22ea7cc
RF
3621 (
3622 $frame & 4 # Extended messsages
3623 ? (
3624 print_lineinfo( ' ' x $stack_depth, "out " ),
3625 print_trace( $LINEINFO, -1, 1, 1, "$sub$al" )
3626 )
3627 : print_lineinfo( ' ' x $stack_depth, "exited $sub$al\n" )
3628
3629 # Standard messages
3630 )
3631 if $frame & 2;
69893cff
RGS
3632
3633 # If we are supposed to show the return value... same as before.
e22ea7cc
RF
3634 if ( $doret eq $stack_depth or $frame & 16 and defined wantarray ) {
3635 local $\ = '';
3636 my $fh = ( $doret eq $stack_depth ? $OUT : $LINEINFO );
3637 print $fh ( ' ' x $stack_depth ) if $frame & 16;
3638 print $fh (
3639 defined wantarray
3640 ? "scalar context return from $sub: "
3641 : "void context return from $sub\n"
3642 );
3643 dumpit( $fh, $ret ) if defined wantarray;
3644 $doret = -2;
69893cff
RGS
3645 } ## end if ($doret eq $stack_depth...
3646
3647 # Return the appropriate scalar value.
e22ea7cc 3648 $ret;
69893cff
RGS
3649 } ## end else [ if (wantarray)
3650} ## end sub sub
3651
3652=head1 EXTENDED COMMAND HANDLING AND THE COMMAND API
3653
3654In Perl 5.8.0, there was a major realignment of the commands and what they did,
3655Most of the changes were to systematize the command structure and to eliminate
3656commands that threw away user input without checking.
3657
3658The following sections describe the code added to make it easy to support
3659multiple command sets with conflicting command names. This section is a start
3660at unifying all command processing to make it simpler to develop commands.
3661
3662Note that all the cmd_[a-zA-Z] subroutines require the command name, a line
3663number, and C<$dbline> (the current line) as arguments.
3664
3665Support functions in this section which have multiple modes of failure C<die>
3666on error; the rest simply return a false value.
3667
3668The user-interface functions (all of the C<cmd_*> functions) just output
3669error messages.
3670
3671=head2 C<%set>
3672
3673The C<%set> hash defines the mapping from command letter to subroutine
3674name suffix.
3675
3676C<%set> is a two-level hash, indexed by set name and then by command name.
3677Note that trying to set the CommandSet to 'foobar' simply results in the
36785.8.0 command set being used, since there's no top-level entry for 'foobar'.
3679
3680=cut
d338d6fe 3681
d12a4851 3682### The API section
f1583d8f 3683
e22ea7cc
RF
3684my %set = ( #
3685 'pre580' => {
3686 'a' => 'pre580_a',
3687 'A' => 'pre580_null',
3688 'b' => 'pre580_b',
3689 'B' => 'pre580_null',
3690 'd' => 'pre580_null',
3691 'D' => 'pre580_D',
3692 'h' => 'pre580_h',
3693 'M' => 'pre580_null',
3694 'O' => 'o',
3695 'o' => 'pre580_null',
3696 'v' => 'M',
3697 'w' => 'v',
3698 'W' => 'pre580_W',
69893cff 3699 },
e22ea7cc
RF
3700 'pre590' => {
3701 '<' => 'pre590_prepost',
3702 '<<' => 'pre590_prepost',
3703 '>' => 'pre590_prepost',
3704 '>>' => 'pre590_prepost',
3705 '{' => 'pre590_prepost',
3706 '{{' => 'pre590_prepost',
69893cff 3707 },
d12a4851 3708);
492652be 3709
69893cff
RGS
3710=head2 C<cmd_wrapper()> (API)
3711
3712C<cmd_wrapper()> allows the debugger to switch command sets
3713depending on the value of the C<CommandSet> option.
3714
3715It tries to look up the command in the X<C<%set>> package-level I<lexical>
3716(which means external entities can't fiddle with it) and create the name of
3717the sub to call based on the value found in the hash (if it's there). I<All>
3718of the commands to be handled in a set have to be added to C<%set>; if they
3719aren't found, the 5.8.0 equivalent is called (if there is one).
3720
3721This code uses symbolic references.
3722
3723=cut
3724
d12a4851 3725sub cmd_wrapper {
69893cff
RGS
3726 my $cmd = shift;
3727 my $line = shift;
3728 my $dblineno = shift;
3729
e22ea7cc 3730 # Assemble the command subroutine's name by looking up the
69893cff
RGS
3731 # command set and command name in %set. If we can't find it,
3732 # default to the older version of the command.
3733 my $call = 'cmd_'
e22ea7cc
RF
3734 . ( $set{$CommandSet}{$cmd}
3735 || ( $cmd =~ /^[<>{]+/o ? 'prepost' : $cmd ) );
69893cff
RGS
3736
3737 # Call the command subroutine, call it by name.
e22ea7cc
RF
3738 return &$call( $cmd, $line, $dblineno );
3739} ## end sub cmd_wrapper
492652be 3740
69893cff
RGS
3741=head3 C<cmd_a> (command)
3742
3743The C<a> command handles pre-execution actions. These are associated with a
3744particular line, so they're stored in C<%dbline>. We default to the current
3745line if none is specified.
3746
3747=cut
3748
d12a4851 3749sub cmd_a {
e22ea7cc
RF
3750 my $cmd = shift;
3751 my $line = shift || ''; # [.|line] expr
3752 my $dbline = shift;
69893cff
RGS
3753
3754 # If it's dot (here), or not all digits, use the current line.
3755 $line =~ s/^(\.|(?:[^\d]))/$dbline/;
3756
e22ea7cc
RF
3757 # Should be a line number followed by an expression.
3758 if ( $line =~ /^\s*(\d*)\s*(\S.+)/ ) {
3759 my ( $lineno, $expr ) = ( $1, $2 );
69893cff
RGS
3760
3761 # If we have an expression ...
e22ea7cc
RF
3762 if ( length $expr ) {
3763
69893cff 3764 # ... but the line isn't breakable, complain.
e22ea7cc
RF
3765 if ( $dbline[$lineno] == 0 ) {
3766 print $OUT
3767 "Line $lineno($dbline[$lineno]) does not have an action?\n";
3768 }
69893cff 3769 else {
e22ea7cc 3770
69893cff
RGS
3771 # It's executable. Record that the line has an action.
3772 $had_breakpoints{$filename} |= 2;
377