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2=head1 NAME
3
be9a9b1d 4perl5db.pl - the perl debugger
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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
be9a9b1d 43I<are> debugger internals, and are therefore subject to change. Future
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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
be9a9b1d 107the second pair applies when it is. The XOR simply allows us to
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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,
be9a9b1d 115such as C<$single>, C<$trace>, and C<$frame>, have I<magical> values composed
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116of 1, 2, 4, etc. (powers of 2) OR'ed together. This allows several pieces
117of state to be stored independently in a single scalar.
118
119A test like
120
121 if ($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
be9a9b1d 135=item *
69893cff 136
be9a9b1d 137First, doing an arithmetical or bitwise operation on a scalar is
69893cff 138just about the fastest thing you can do in Perl: C<use constant> actually
be9a9b1d 139creates a subroutine call, and array and hash lookups are much slower. Is
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140this over-optimization at the expense of readability? Possibly, but the
141debugger accesses these variables a I<lot>. Any rewrite of the code will
142probably have to benchmark alternate implementations and see which is the
143best balance of readability and speed, and then document how it actually
144works.
145
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146=item *
147
148Second, it's very easy to serialize a scalar number. This is done in
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149the restart code; the debugger state variables are saved in C<%ENV> and then
150restored when the debugger is restarted. Having them be just numbers makes
151this trivial.
152
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153=item *
154
155Third, some of these variables are being shared with the Perl core
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156smack in the middle of the interpreter's execution loop. It's much faster for
157a C program (like the interpreter) to check a bit in a scalar than to access
158several different variables (or a Perl array).
159
160=back
161
162=head2 What are those C<XXX> comments for?
163
164Any comment containing C<XXX> means that the comment is either somewhat
165speculative - it's not exactly clear what a given variable or chunk of
166code is doing, or that it is incomplete - the basics may be clear, but the
167subtleties are not completely documented.
168
169Send in a patch if you can clear up, fill out, or clarify an C<XXX>.
170
171=head1 DATA STRUCTURES MAINTAINED BY CORE
172
173There are a number of special data structures provided to the debugger by
174the Perl interpreter.
175
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176The array C<@{$main::{'_<'.$filename}}> (aliased locally to C<@dbline>
177via glob assignment) contains the text from C<$filename>, with each
178element corresponding to a single line of C<$filename>. Additionally,
179breakable lines will be dualvars with the numeric component being the
180memory address of a COP node. Non-breakable lines are dualvar to 0.
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181
182The hash C<%{'_<'.$filename}> (aliased locally to C<%dbline> via glob
183assignment) contains breakpoints and actions. The keys are line numbers;
184you can set individual values, but not the whole hash. The Perl interpreter
185uses this hash to determine where breakpoints have been set. Any true value is
be9a9b1d 186considered to be a breakpoint; C<perl5db.pl> uses C<$break_condition\0$action>.
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187Values are magical in numeric context: 1 if the line is breakable, 0 if not.
188
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189The scalar C<${"_<$filename"}> simply contains the string C<_<$filename>.
190This is also the case for evaluated strings that contain subroutines, or
191which are currently being executed. The $filename for C<eval>ed strings looks
d24ca0c5 192like C<(eval 34).
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193
194=head1 DEBUGGER STARTUP
195
196When C<perl5db.pl> starts, it reads an rcfile (C<perl5db.ini> for
197non-interactive sessions, C<.perldb> for interactive ones) that can set a number
198of options. In addition, this file may define a subroutine C<&afterinit>
199that will be executed (in the debugger's context) after the debugger has
200initialized itself.
201
202Next, it checks the C<PERLDB_OPTS> environment variable and treats its
be9a9b1d 203contents as the argument of a C<o> command in the debugger.
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204
205=head2 STARTUP-ONLY OPTIONS
206
207The following options can only be specified at startup.
208To set them in your rcfile, add a call to
209C<&parse_options("optionName=new_value")>.
210
211=over 4
212
213=item * TTY
214
215the TTY to use for debugging i/o.
216
217=item * noTTY
218
219if set, goes in NonStop mode. On interrupt, if TTY is not set,
b0e77abc 220uses the value of noTTY or F<$HOME/.perldbtty$$> to find TTY using
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221Term::Rendezvous. Current variant is to have the name of TTY in this
222file.
223
224=item * ReadLine
225
5561b870 226if false, a dummy ReadLine is used, so you can debug
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227ReadLine applications.
228
229=item * NonStop
230
231if true, no i/o is performed until interrupt.
232
233=item * LineInfo
234
235file or pipe to print line number info to. If it is a
236pipe, a short "emacs like" message is used.
237
238=item * RemotePort
239
240host:port to connect to on remote host for remote debugging.
241
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242=item * HistFile
243
244file to store session history to. There is no default and so no
245history file is written unless this variable is explicitly set.
246
247=item * HistSize
248
249number of commands to store to the file specified in C<HistFile>.
250Default is 100.
251
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252=back
253
254=head3 SAMPLE RCFILE
255
256 &parse_options("NonStop=1 LineInfo=db.out");
257 sub afterinit { $trace = 1; }
258
259The script will run without human intervention, putting trace
260information into C<db.out>. (If you interrupt it, you had better
be9a9b1d 261reset C<LineInfo> to something I<interactive>!)
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262
263=head1 INTERNALS DESCRIPTION
264
265=head2 DEBUGGER INTERFACE VARIABLES
266
267Perl supplies the values for C<%sub>. It effectively inserts
be9a9b1d 268a C<&DB::DB();> in front of each place that can have a
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269breakpoint. At each subroutine call, it calls C<&DB::sub> with
270C<$DB::sub> set to the called subroutine. It also inserts a C<BEGIN
271{require 'perl5db.pl'}> before the first line.
272
273After each C<require>d file is compiled, but before it is executed, a
274call to C<&DB::postponed($main::{'_<'.$filename})> is done. C<$filename>
275is the expanded name of the C<require>d file (as found via C<%INC>).
276
277=head3 IMPORTANT INTERNAL VARIABLES
278
279=head4 C<$CreateTTY>
280
281Used to control when the debugger will attempt to acquire another TTY to be
282used for input.
283
284=over
285
286=item * 1 - on C<fork()>
287
288=item * 2 - debugger is started inside debugger
289
290=item * 4 - on startup
291
292=back
293
294=head4 C<$doret>
295
296The value -2 indicates that no return value should be printed.
297Any other positive value causes C<DB::sub> to print return values.
298
299=head4 C<$evalarg>
300
301The item to be eval'ed by C<DB::eval>. Used to prevent messing with the current
302contents of C<@_> when C<DB::eval> is called.
303
304=head4 C<$frame>
305
306Determines what messages (if any) will get printed when a subroutine (or eval)
307is entered or exited.
308
309=over 4
310
311=item * 0 - No enter/exit messages
312
be9a9b1d 313=item * 1 - Print I<entering> messages on subroutine entry
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314
315=item * 2 - Adds exit messages on subroutine exit. If no other flag is on, acts like 1+2.
316
be9a9b1d 317=item * 4 - Extended messages: C<< <in|out> I<context>=I<fully-qualified sub name> from I<file>:I<line> >>. If no other flag is on, acts like 1+4.
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318
319=item * 8 - Adds parameter information to messages, and overloaded stringify and tied FETCH is enabled on the printed arguments. Ignored if C<4> is not on.
320
321=item * 16 - Adds C<I<context> return from I<subname>: I<value>> messages on subroutine/eval exit. Ignored if C<4> is is not on.
322
323=back
324
be9a9b1d 325To get everything, use C<$frame=30> (or C<o f=30> as a debugger command).
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326The debugger internally juggles the value of C<$frame> during execution to
327protect external modules that the debugger uses from getting traced.
328
329=head4 C<$level>
330
331Tracks current debugger nesting level. Used to figure out how many
332C<E<lt>E<gt>> pairs to surround the line number with when the debugger
333outputs a prompt. Also used to help determine if the program has finished
334during command parsing.
335
336=head4 C<$onetimeDump>
337
338Controls what (if anything) C<DB::eval()> will print after evaluating an
339expression.
340
341=over 4
342
343=item * C<undef> - don't print anything
344
345=item * C<dump> - use C<dumpvar.pl> to display the value returned
346
347=item * C<methods> - print the methods callable on the first item returned
348
349=back
350
351=head4 C<$onetimeDumpDepth>
352
be9a9b1d 353Controls how far down C<dumpvar.pl> will go before printing C<...> while
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354dumping a structure. Numeric. If C<undef>, print all levels.
355
356=head4 C<$signal>
357
358Used to track whether or not an C<INT> signal has been detected. C<DB::DB()>,
359which is called before every statement, checks this and puts the user into
360command mode if it finds C<$signal> set to a true value.
361
362=head4 C<$single>
363
364Controls behavior during single-stepping. Stacked in C<@stack> on entry to
365each subroutine; popped again at the end of each subroutine.
366
367=over 4
368
369=item * 0 - run continuously.
370
be9a9b1d 371=item * 1 - single-step, go into subs. The C<s> command.
69893cff 372
be9a9b1d 373=item * 2 - single-step, don't go into subs. The C<n> command.
69893cff 374
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375=item * 4 - print current sub depth (turned on to force this when C<too much
376recursion> occurs.
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377
378=back
379
380=head4 C<$trace>
381
382Controls the output of trace information.
383
384=over 4
385
386=item * 1 - The C<t> command was entered to turn on tracing (every line executed is printed)
387
388=item * 2 - watch expressions are active
389
390=item * 4 - user defined a C<watchfunction()> in C<afterinit()>
391
392=back
393
394=head4 C<$slave_editor>
395
3961 if C<LINEINFO> was directed to a pipe; 0 otherwise.
397
398=head4 C<@cmdfhs>
399
400Stack of filehandles that C<DB::readline()> will read commands from.
401Manipulated by the debugger's C<source> command and C<DB::readline()> itself.
402
403=head4 C<@dbline>
404
405Local alias to the magical line array, C<@{$main::{'_<'.$filename}}> ,
406supplied by the Perl interpreter to the debugger. Contains the source.
407
408=head4 C<@old_watch>
409
410Previous values of watch expressions. First set when the expression is
411entered; reset whenever the watch expression changes.
412
413=head4 C<@saved>
414
415Saves important globals (C<$@>, C<$!>, C<$^E>, C<$,>, C<$/>, C<$\>, C<$^W>)
416so that the debugger can substitute safe values while it's running, and
417restore them when it returns control.
418
419=head4 C<@stack>
420
421Saves the current value of C<$single> on entry to a subroutine.
422Manipulated by the C<c> command to turn off tracing in all subs above the
423current one.
424
425=head4 C<@to_watch>
426
427The 'watch' expressions: to be evaluated before each line is executed.
428
429=head4 C<@typeahead>
430
431The typeahead buffer, used by C<DB::readline>.
432
433=head4 C<%alias>
434
435Command aliases. Stored as character strings to be substituted for a command
436entered.
437
438=head4 C<%break_on_load>
439
440Keys are file names, values are 1 (break when this file is loaded) or undef
441(don't break when it is loaded).
442
443=head4 C<%dbline>
444
be9a9b1d 445Keys are line numbers, values are C<condition\0action>. If used in numeric
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446context, values are 0 if not breakable, 1 if breakable, no matter what is
447in the actual hash entry.
448
449=head4 C<%had_breakpoints>
450
451Keys are file names; values are bitfields:
452
453=over 4
454
455=item * 1 - file has a breakpoint in it.
456
457=item * 2 - file has an action in it.
458
459=back
460
461A zero or undefined value means this file has neither.
462
463=head4 C<%option>
464
465Stores the debugger options. These are character string values.
466
467=head4 C<%postponed>
468
469Saves breakpoints for code that hasn't been compiled yet.
470Keys are subroutine names, values are:
471
472=over 4
473
be9a9b1d 474=item * C<compile> - break when this sub is compiled
69893cff 475
be9a9b1d 476=item * C<< break +0 if <condition> >> - break (conditionally) at the start of this routine. The condition will be '1' if no condition was specified.
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477
478=back
479
480=head4 C<%postponed_file>
481
482This hash keeps track of breakpoints that need to be set for files that have
483not yet been compiled. Keys are filenames; values are references to hashes.
484Each of these hashes is keyed by line number, and its values are breakpoint
be9a9b1d 485definitions (C<condition\0action>).
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486
487=head1 DEBUGGER INITIALIZATION
488
489The debugger's initialization actually jumps all over the place inside this
490package. This is because there are several BEGIN blocks (which of course
491execute immediately) spread through the code. Why is that?
492
493The debugger needs to be able to change some things and set some things up
494before the debugger code is compiled; most notably, the C<$deep> variable that
495C<DB::sub> uses to tell when a program has recursed deeply. In addition, the
496debugger has to turn off warnings while the debugger code is compiled, but then
497restore them to their original setting before the program being debugged begins
498executing.
499
500The first C<BEGIN> block simply turns off warnings by saving the current
501setting of C<$^W> and then setting it to zero. The second one initializes
502the debugger variables that are needed before the debugger begins executing.
503The third one puts C<$^X> back to its former value.
504
505We'll detail the second C<BEGIN> block later; just remember that if you need
506to initialize something before the debugger starts really executing, that's
507where it has to go.
508
509=cut
510
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511package DB;
512
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513use strict;
514
c7e68384 515BEGIN {eval 'use IO::Handle'}; # Needed for flush only? breaks under miniperl
9eba6a4e 516
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517BEGIN {
518 require feature;
519 $^V =~ /^v(\d+\.\d+)/;
520 feature->import(":$1");
521}
522
54d04a52 523# Debugger for Perl 5.00x; perl5db.pl patch level:
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524use vars qw($VERSION $header);
525
b5afd346 526$VERSION = '1.39_04';
69893cff 527
e22ea7cc 528$header = "perl5db.pl version $VERSION";
d338d6fe 529
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530=head1 DEBUGGER ROUTINES
531
532=head2 C<DB::eval()>
533
534This function replaces straight C<eval()> inside the debugger; it simplifies
535the process of evaluating code in the user's context.
536
537The code to be evaluated is passed via the package global variable
538C<$DB::evalarg>; this is done to avoid fiddling with the contents of C<@_>.
539
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540Before we do the C<eval()>, we preserve the current settings of C<$trace>,
541C<$single>, C<$^D> and C<$usercontext>. The latter contains the
542preserved values of C<$@>, C<$!>, C<$^E>, C<$,>, C<$/>, C<$\>, C<$^W> and the
543user's current package, grabbed when C<DB::DB> got control. This causes the
544proper context to be used when the eval is actually done. Afterward, we
545restore C<$trace>, C<$single>, and C<$^D>.
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546
547Next we need to handle C<$@> without getting confused. We save C<$@> in a
548local lexical, localize C<$saved[0]> (which is where C<save()> will put
549C<$@>), and then call C<save()> to capture C<$@>, C<$!>, C<$^E>, C<$,>,
550C<$/>, C<$\>, and C<$^W>) and set C<$,>, C<$/>, C<$\>, and C<$^W> to values
551considered sane by the debugger. If there was an C<eval()> error, we print
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552it on the debugger's output. If C<$onetimedump> is defined, we call
553C<dumpit> if it's set to 'dump', or C<methods> if it's set to
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554'methods'. Setting it to something else causes the debugger to do the eval
555but not print the result - handy if you want to do something else with it
556(the "watch expressions" code does this to get the value of the watch
557expression but not show it unless it matters).
558
559In any case, we then return the list of output from C<eval> to the caller,
560and unwinding restores the former version of C<$@> in C<@saved> as well
561(the localization of C<$saved[0]> goes away at the end of this scope).
562
563=head3 Parameters and variables influencing execution of DB::eval()
564
565C<DB::eval> isn't parameterized in the standard way; this is to keep the
566debugger's calls to C<DB::eval()> from mucking with C<@_>, among other things.
567The variables listed below influence C<DB::eval()>'s execution directly.
568
569=over 4
570
571=item C<$evalarg> - the thing to actually be eval'ed
572
be9a9b1d 573=item C<$trace> - Current state of execution tracing
69893cff 574
be9a9b1d 575=item C<$single> - Current state of single-stepping
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576
577=item C<$onetimeDump> - what is to be displayed after the evaluation
578
579=item C<$onetimeDumpDepth> - how deep C<dumpit()> should go when dumping results
580
581=back
582
583The following variables are altered by C<DB::eval()> during its execution. They
584are "stacked" via C<local()>, enabling recursive calls to C<DB::eval()>.
585
586=over 4
587
588=item C<@res> - used to capture output from actual C<eval>.
589
590=item C<$otrace> - saved value of C<$trace>.
591
592=item C<$osingle> - saved value of C<$single>.
593
594=item C<$od> - saved value of C<$^D>.
595
596=item C<$saved[0]> - saved value of C<$@>.
597
598=item $\ - for output of C<$@> if there is an evaluation error.
599
600=back
601
602=head3 The problem of lexicals
603
604The context of C<DB::eval()> presents us with some problems. Obviously,
605we want to be 'sandboxed' away from the debugger's internals when we do
606the eval, but we need some way to control how punctuation variables and
607debugger globals are used.
608
609We can't use local, because the code inside C<DB::eval> can see localized
610variables; and we can't use C<my> either for the same reason. The code
611in this routine compromises and uses C<my>.
612
613After this routine is over, we don't have user code executing in the debugger's
614context, so we can use C<my> freely.
615
616=cut
617
618############################################## Begin lexical danger zone
619
620# 'my' variables used here could leak into (that is, be visible in)
621# the context that the code being evaluated is executing in. This means that
622# the code could modify the debugger's variables.
623#
624# Fiddling with the debugger's context could be Bad. We insulate things as
625# much as we can.
626
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627use vars qw(
628 @args
629 %break_on_load
630 @cmdfhs
631 $CommandSet
632 $CreateTTY
633 $DBGR
634 @dbline
635 $dbline
636 %dbline
637 $dieLevel
638 $evalarg
639 $filename
640 $frame
641 $hist
642 $histfile
643 $histsize
644 $ImmediateStop
645 $IN
646 $inhibit_exit
647 @ini_INC
648 $ini_warn
649 $line
650 $maxtrace
651 $od
652 $onetimeDump
653 $onetimedumpDepth
654 %option
655 @options
656 $osingle
657 $otrace
658 $OUT
659 $packname
660 $pager
661 $post
662 %postponed
663 $prc
664 $pre
665 $pretype
666 $psh
667 @RememberOnROptions
668 $remoteport
669 @res
670 $rl
671 @saved
672 $signal
673 $signalLevel
674 $single
675 $start
676 $sub
677 %sub
678 $subname
679 $term
680 $trace
681 $usercontext
682 $warnLevel
683 $window
684);
685
686# Used to save @ARGV and extract any debugger-related flags.
687use vars qw(@ARGS);
688
689# Used to prevent multiple entries to diesignal()
690# (if for instance diesignal() itself dies)
691use vars qw($panic);
692
693# Used to prevent the debugger from running nonstop
694# after a restart
695use vars qw($second_time);
696
697sub _calc_usercontext {
698 my ($package) = @_;
699
700 # Cancel strict completely for the evaluated code, so the code
701 # the user evaluates won't be affected by it. (Shlomi Fish)
702 return 'no strict; ($@, $!, $^E, $,, $/, $\, $^W) = @saved;'
703 . "package $package;"; # this won't let them modify, alas
704}
705
c1051fcf 706sub eval {
69893cff 707
c1051fcf 708 # 'my' would make it visible from user code
e22ea7cc 709 # but so does local! --tchrist
69893cff 710 # Remember: this localizes @DB::res, not @main::res.
c1051fcf
IZ
711 local @res;
712 {
e22ea7cc
RF
713
714 # Try to keep the user code from messing with us. Save these so that
715 # even if the eval'ed code changes them, we can put them back again.
716 # Needed because the user could refer directly to the debugger's
69893cff
RGS
717 # package globals (and any 'my' variables in this containing scope)
718 # inside the eval(), and we want to try to stay safe.
e22ea7cc 719 local $otrace = $trace;
69893cff
RGS
720 local $osingle = $single;
721 local $od = $^D;
722
723 # Untaint the incoming eval() argument.
724 { ($evalarg) = $evalarg =~ /(.*)/s; }
725
e22ea7cc 726 # $usercontext built in DB::DB near the comment
69893cff
RGS
727 # "set up the context for DB::eval ..."
728 # Evaluate and save any results.
e22ea7cc 729 @res = eval "$usercontext $evalarg;\n"; # '\n' for nice recursive debug
69893cff
RGS
730
731 # Restore those old values.
732 $trace = $otrace;
733 $single = $osingle;
734 $^D = $od;
c1051fcf 735 }
69893cff
RGS
736
737 # Save the current value of $@, and preserve it in the debugger's copy
738 # of the saved precious globals.
c1051fcf 739 my $at = $@;
69893cff
RGS
740
741 # Since we're only saving $@, we only have to localize the array element
742 # that it will be stored in.
e22ea7cc 743 local $saved[0]; # Preserve the old value of $@
c1051fcf 744 eval { &DB::save };
69893cff
RGS
745
746 # Now see whether we need to report an error back to the user.
c1051fcf 747 if ($at) {
69893cff
RGS
748 local $\ = '';
749 print $OUT $at;
750 }
751
752 # Display as required by the caller. $onetimeDump and $onetimedumpDepth
753 # are package globals.
754 elsif ($onetimeDump) {
e22ea7cc
RF
755 if ( $onetimeDump eq 'dump' ) {
756 local $option{dumpDepth} = $onetimedumpDepth
757 if defined $onetimedumpDepth;
758 dumpit( $OUT, \@res );
759 }
760 elsif ( $onetimeDump eq 'methods' ) {
761 methods( $res[0] );
762 }
69893cff 763 } ## end elsif ($onetimeDump)
c1051fcf 764 @res;
69893cff
RGS
765} ## end sub eval
766
767############################################## End lexical danger zone
c1051fcf 768
e22ea7cc
RF
769# After this point it is safe to introduce lexicals.
770# The code being debugged will be executing in its own context, and
69893cff 771# can't see the inside of the debugger.
d338d6fe 772#
e22ea7cc 773# However, one should not overdo it: leave as much control from outside as
69893cff
RGS
774# possible. If you make something a lexical, it's not going to be addressable
775# from outside the debugger even if you know its name.
776
d338d6fe
PP
777# This file is automatically included if you do perl -d.
778# It's probably not useful to include this yourself.
779#
e22ea7cc 780# Before venturing further into these twisty passages, it is
2f7e9187
MS
781# wise to read the perldebguts man page or risk the ire of dragons.
782#
69893cff
RGS
783# (It should be noted that perldebguts will tell you a lot about
784# the underlying mechanics of how the debugger interfaces into the
785# Perl interpreter, but not a lot about the debugger itself. The new
786# comments in this code try to address this problem.)
787
d338d6fe 788# Note that no subroutine call is possible until &DB::sub is defined
36477c24 789# (for subroutines defined outside of the package DB). In fact the same is
d338d6fe 790# true if $deep is not defined.
055fd3a9
GS
791
792# Enhanced by ilya@math.ohio-state.edu (Ilya Zakharevich)
055fd3a9
GS
793
794# modified Perl debugger, to be run from Emacs in perldb-mode
795# Ray Lischner (uunet!mntgfx!lisch) as of 5 Nov 1990
796# Johan Vromans -- upgrade to 4.0 pl 10
797# Ilya Zakharevich -- patches after 5.001 (and some before ;-)
6fae1ad7 798########################################################################
d338d6fe 799
69893cff
RGS
800=head1 DEBUGGER INITIALIZATION
801
802The debugger starts up in phases.
803
804=head2 BASIC SETUP
805
806First, it initializes the environment it wants to run in: turning off
807warnings during its own compilation, defining variables which it will need
808to avoid warnings later, setting itself up to not exit when the program
809terminates, and defaulting to printing return values for the C<r> command.
810
811=cut
812
eda6e075 813# Needed for the statement after exec():
69893cff
RGS
814#
815# This BEGIN block is simply used to switch off warnings during debugger
98dc9551 816# compilation. Probably it would be better practice to fix the warnings,
69893cff 817# but this is how it's done at the moment.
eda6e075 818
e22ea7cc
RF
819BEGIN {
820 $ini_warn = $^W;
821 $^W = 0;
822} # Switch compilation warnings off until another BEGIN.
d12a4851 823
69893cff
RGS
824local ($^W) = 0; # Switch run-time warnings off during init.
825
2cbb2ee1
RGS
826=head2 THREADS SUPPORT
827
828If we are running under a threaded Perl, we require threads and threads::shared
829if the environment variable C<PERL5DB_THREADED> is set, to enable proper
830threaded debugger control. C<-dt> can also be used to set this.
831
832Each new thread will be announced and the debugger prompt will always inform
833you of each new thread created. It will also indicate the thread id in which
834we are currently running within the prompt like this:
835
836 [tid] DB<$i>
837
838Where C<[tid]> is an integer thread id and C<$i> is the familiar debugger
839command prompt. The prompt will show: C<[0]> when running under threads, but
840not actually in a thread. C<[tid]> is consistent with C<gdb> usage.
841
842While running under threads, when you set or delete a breakpoint (etc.), this
843will apply to all threads, not just the currently running one. When you are
844in a currently executing thread, you will stay there until it completes. With
845the current implementation it is not currently possible to hop from one thread
846to another.
847
848The C<e> and C<E> commands are currently fairly minimal - see C<h e> and C<h E>.
849
850Note that threading support was built into the debugger as of Perl version
851C<5.8.6> and debugger version C<1.2.8>.
852
853=cut
854
855BEGIN {
856 # ensure we can share our non-threaded variables or no-op
857 if ($ENV{PERL5DB_THREADED}) {
858 require threads;
859 require threads::shared;
860 import threads::shared qw(share);
861 $DBGR;
862 share(\$DBGR);
863 lock($DBGR);
864 print "Threads support enabled\n";
865 } else {
866 *lock = sub(*) {};
867 *share = sub(*) {};
868 }
869}
870
69893cff
RGS
871# This would probably be better done with "use vars", but that wasn't around
872# when this code was originally written. (Neither was "use strict".) And on
873# the principle of not fiddling with something that was working, this was
874# left alone.
875warn( # Do not ;-)
2cbb2ee1 876 # These variables control the execution of 'dumpvar.pl'.
69893cff
RGS
877 $dumpvar::hashDepth,
878 $dumpvar::arrayDepth,
879 $dumpvar::dumpDBFiles,
880 $dumpvar::dumpPackages,
881 $dumpvar::quoteHighBit,
882 $dumpvar::printUndef,
883 $dumpvar::globPrint,
884 $dumpvar::usageOnly,
885
69893cff
RGS
886 # used to control die() reporting in diesignal()
887 $Carp::CarpLevel,
888
69893cff 889
69893cff
RGS
890 )
891 if 0;
d338d6fe 892
422c59bf 893# without threads, $filename is not defined until DB::DB is called
2cbb2ee1 894foreach my $k (keys (%INC)) {
bc6438f2 895 &share(\$main::{'_<'.$filename}) if defined $filename;
2cbb2ee1
RGS
896};
897
54d04a52 898# Command-line + PERLLIB:
69893cff 899# Save the contents of @INC before they are modified elsewhere.
54d04a52
IZ
900@ini_INC = @INC;
901
69893cff
RGS
902# This was an attempt to clear out the previous values of various
903# trapped errors. Apparently it didn't help. XXX More info needed!
d338d6fe
PP
904# $prevwarn = $prevdie = $prevbus = $prevsegv = ''; # Does not help?!
905
69893cff
RGS
906# We set these variables to safe values. We don't want to blindly turn
907# off warnings, because other packages may still want them.
e22ea7cc
RF
908$trace = $signal = $single = 0; # Uninitialized warning suppression
909 # (local $^W cannot help - other packages!).
69893cff
RGS
910
911# Default to not exiting when program finishes; print the return
912# value when the 'r' command is used to return from a subroutine.
55497cff 913$inhibit_exit = $option{PrintRet} = 1;
d338d6fe 914
6b24a4b7
SF
915use vars qw($trace_to_depth);
916
5e2b42dd
SF
917# Default to 1E9 so it won't be limited to a certain recursion depth.
918$trace_to_depth = 1E9;
bdba49ad 919
69893cff
RGS
920=head1 OPTION PROCESSING
921
922The debugger's options are actually spread out over the debugger itself and
923C<dumpvar.pl>; some of these are variables to be set, while others are
924subs to be called with a value. To try to make this a little easier to
925manage, the debugger uses a few data structures to define what options
926are legal and how they are to be processed.
927
928First, the C<@options> array defines the I<names> of all the options that
929are to be accepted.
930
931=cut
932
933@options = qw(
5561b870 934 CommandSet HistFile HistSize
e22ea7cc
RF
935 hashDepth arrayDepth dumpDepth
936 DumpDBFiles DumpPackages DumpReused
937 compactDump veryCompact quote
938 HighBit undefPrint globPrint
939 PrintRet UsageOnly frame
940 AutoTrace TTY noTTY
941 ReadLine NonStop LineInfo
942 maxTraceLen recallCommand ShellBang
943 pager tkRunning ornaments
944 signalLevel warnLevel dieLevel
945 inhibit_exit ImmediateStop bareStringify
946 CreateTTY RemotePort windowSize
584420f0 947 DollarCaretP
e22ea7cc 948);
d12a4851 949
584420f0 950@RememberOnROptions = qw(DollarCaretP);
d12a4851 951
69893cff
RGS
952=pod
953
954Second, C<optionVars> lists the variables that each option uses to save its
955state.
956
957=cut
958
6b24a4b7
SF
959use vars qw(%optionVars);
960
69893cff 961%optionVars = (
e22ea7cc
RF
962 hashDepth => \$dumpvar::hashDepth,
963 arrayDepth => \$dumpvar::arrayDepth,
964 CommandSet => \$CommandSet,
965 DumpDBFiles => \$dumpvar::dumpDBFiles,
966 DumpPackages => \$dumpvar::dumpPackages,
967 DumpReused => \$dumpvar::dumpReused,
968 HighBit => \$dumpvar::quoteHighBit,
969 undefPrint => \$dumpvar::printUndef,
970 globPrint => \$dumpvar::globPrint,
971 UsageOnly => \$dumpvar::usageOnly,
972 CreateTTY => \$CreateTTY,
973 bareStringify => \$dumpvar::bareStringify,
974 frame => \$frame,
975 AutoTrace => \$trace,
976 inhibit_exit => \$inhibit_exit,
977 maxTraceLen => \$maxtrace,
978 ImmediateStop => \$ImmediateStop,
979 RemotePort => \$remoteport,
980 windowSize => \$window,
5561b870
AK
981 HistFile => \$histfile,
982 HistSize => \$histsize,
69893cff
RGS
983);
984
985=pod
986
987Third, C<%optionAction> defines the subroutine to be called to process each
988option.
989
990=cut
991
6b24a4b7
SF
992use vars qw(%optionAction);
993
69893cff
RGS
994%optionAction = (
995 compactDump => \&dumpvar::compactDump,
996 veryCompact => \&dumpvar::veryCompact,
997 quote => \&dumpvar::quote,
998 TTY => \&TTY,
999 noTTY => \&noTTY,
1000 ReadLine => \&ReadLine,
1001 NonStop => \&NonStop,
1002 LineInfo => \&LineInfo,
1003 recallCommand => \&recallCommand,
1004 ShellBang => \&shellBang,
1005 pager => \&pager,
1006 signalLevel => \&signalLevel,
1007 warnLevel => \&warnLevel,
1008 dieLevel => \&dieLevel,
1009 tkRunning => \&tkRunning,
1010 ornaments => \&ornaments,
1011 RemotePort => \&RemotePort,
1012 DollarCaretP => \&DollarCaretP,
d12a4851
JH
1013);
1014
69893cff
RGS
1015=pod
1016
1017Last, the C<%optionRequire> notes modules that must be C<require>d if an
1018option is used.
1019
1020=cut
d338d6fe 1021
69893cff
RGS
1022# Note that this list is not complete: several options not listed here
1023# actually require that dumpvar.pl be loaded for them to work, but are
1024# not in the table. A subsequent patch will correct this problem; for
1025# the moment, we're just recommenting, and we are NOT going to change
1026# function.
6b24a4b7
SF
1027use vars qw(%optionRequire);
1028
eda6e075 1029%optionRequire = (
69893cff
RGS
1030 compactDump => 'dumpvar.pl',
1031 veryCompact => 'dumpvar.pl',
1032 quote => 'dumpvar.pl',
e22ea7cc 1033);
69893cff
RGS
1034
1035=pod
1036
1037There are a number of initialization-related variables which can be set
1038by putting code to set them in a BEGIN block in the C<PERL5DB> environment
1039variable. These are:
1040
1041=over 4
1042
1043=item C<$rl> - readline control XXX needs more explanation
1044
1045=item C<$warnLevel> - whether or not debugger takes over warning handling
1046
1047=item C<$dieLevel> - whether or not debugger takes over die handling
1048
1049=item C<$signalLevel> - whether or not debugger takes over signal handling
1050
1051=item C<$pre> - preprompt actions (array reference)
1052
1053=item C<$post> - postprompt actions (array reference)
1054
1055=item C<$pretype>
1056
1057=item C<$CreateTTY> - whether or not to create a new TTY for this debugger
1058
1059=item C<$CommandSet> - which command set to use (defaults to new, documented set)
1060
1061=back
1062
1063=cut
d338d6fe
PP
1064
1065# These guys may be defined in $ENV{PERL5DB} :
69893cff
RGS
1066$rl = 1 unless defined $rl;
1067$warnLevel = 1 unless defined $warnLevel;
1068$dieLevel = 1 unless defined $dieLevel;
1069$signalLevel = 1 unless defined $signalLevel;
1070$pre = [] unless defined $pre;
1071$post = [] unless defined $post;
1072$pretype = [] unless defined $pretype;
1073$CreateTTY = 3 unless defined $CreateTTY;
1074$CommandSet = '580' unless defined $CommandSet;
1075
2cbb2ee1
RGS
1076share($rl);
1077share($warnLevel);
1078share($dieLevel);
1079share($signalLevel);
1080share($pre);
1081share($post);
1082share($pretype);
1083share($rl);
1084share($CreateTTY);
1085share($CommandSet);
1086
69893cff
RGS
1087=pod
1088
1089The default C<die>, C<warn>, and C<signal> handlers are set up.
1090
1091=cut
055fd3a9 1092
d338d6fe
PP
1093warnLevel($warnLevel);
1094dieLevel($dieLevel);
1095signalLevel($signalLevel);
055fd3a9 1096
69893cff
RGS
1097=pod
1098
1099The pager to be used is needed next. We try to get it from the
5561b870 1100environment first. If it's not defined there, we try to find it in
69893cff
RGS
1101the Perl C<Config.pm>. If it's not there, we default to C<more>. We
1102then call the C<pager()> function to save the pager name.
1103
1104=cut
1105
1106# This routine makes sure $pager is set up so that '|' can use it.
4865a36d 1107pager(
e22ea7cc 1108
69893cff 1109 # If PAGER is defined in the environment, use it.
e22ea7cc
RF
1110 defined $ENV{PAGER}
1111 ? $ENV{PAGER}
69893cff
RGS
1112
1113 # If not, see if Config.pm defines it.
e22ea7cc
RF
1114 : eval { require Config }
1115 && defined $Config::Config{pager}
1116 ? $Config::Config{pager}
69893cff
RGS
1117
1118 # If not, fall back to 'more'.
e22ea7cc
RF
1119 : 'more'
1120 )
1121 unless defined $pager;
69893cff
RGS
1122
1123=pod
1124
1125We set up the command to be used to access the man pages, the command
be9a9b1d
AT
1126recall character (C<!> unless otherwise defined) and the shell escape
1127character (C<!> unless otherwise defined). Yes, these do conflict, and
69893cff
RGS
1128neither works in the debugger at the moment.
1129
1130=cut
1131
055fd3a9 1132setman();
69893cff
RGS
1133
1134# Set up defaults for command recall and shell escape (note:
1135# these currently don't work in linemode debugging).
d338d6fe 1136&recallCommand("!") unless defined $prc;
69893cff
RGS
1137&shellBang("!") unless defined $psh;
1138
1139=pod
1140
1141We then set up the gigantic string containing the debugger help.
1142We also set the limit on the number of arguments we'll display during a
1143trace.
1144
1145=cut
1146
04e43a21 1147sethelp();
69893cff
RGS
1148
1149# If we didn't get a default for the length of eval/stack trace args,
1150# set it here.
1d06cb2d 1151$maxtrace = 400 unless defined $maxtrace;
69893cff
RGS
1152
1153=head2 SETTING UP THE DEBUGGER GREETING
1154
be9a9b1d 1155The debugger I<greeting> helps to inform the user how many debuggers are
69893cff
RGS
1156running, and whether the current debugger is the primary or a child.
1157
1158If we are the primary, we just hang onto our pid so we'll have it when
1159or if we start a child debugger. If we are a child, we'll set things up
1160so we'll have a unique greeting and so the parent will give us our own
1161TTY later.
1162
1163We save the current contents of the C<PERLDB_PIDS> environment variable
1164because we mess around with it. We'll also need to hang onto it because
1165we'll need it if we restart.
1166
1167Child debuggers make a label out of the current PID structure recorded in
1168PERLDB_PIDS plus the new PID. They also mark themselves as not having a TTY
1169yet so the parent will give them one later via C<resetterm()>.
1170
1171=cut
1172
e22ea7cc 1173# Save the current contents of the environment; we're about to
69893cff 1174# much with it. We'll need this if we have to restart.
6b24a4b7 1175use vars qw($ini_pids);
f1583d8f 1176$ini_pids = $ENV{PERLDB_PIDS};
69893cff 1177
6b24a4b7
SF
1178use vars qw ($pids $term_pid);
1179
e22ea7cc
RF
1180if ( defined $ENV{PERLDB_PIDS} ) {
1181
69893cff 1182 # We're a child. Make us a label out of the current PID structure
e22ea7cc 1183 # recorded in PERLDB_PIDS plus our (new) PID. Mark us as not having
69893cff 1184 # a term yet so the parent will give us one later via resetterm().
55f4245e
JM
1185
1186 my $env_pids = $ENV{PERLDB_PIDS};
1187 $pids = "[$env_pids]";
1188
1189 # Unless we are on OpenVMS, all programs under the DCL shell run under
1190 # the same PID.
1191
1192 if (($^O eq 'VMS') && ($env_pids =~ /\b$$\b/)) {
1193 $term_pid = $$;
1194 }
1195 else {
1196 $ENV{PERLDB_PIDS} .= "->$$";
1197 $term_pid = -1;
1198 }
1199
69893cff
RGS
1200} ## end if (defined $ENV{PERLDB_PIDS...
1201else {
e22ea7cc
RF
1202
1203 # We're the parent PID. Initialize PERLDB_PID in case we end up with a
69893cff
RGS
1204 # child debugger, and mark us as the parent, so we'll know to set up
1205 # more TTY's is we have to.
1206 $ENV{PERLDB_PIDS} = "$$";
619a0444 1207 $pids = "[pid=$$]";
e22ea7cc 1208 $term_pid = $$;
f1583d8f 1209}
69893cff 1210
6b24a4b7 1211use vars qw($pidprompt);
f1583d8f 1212$pidprompt = '';
69893cff
RGS
1213
1214# Sets up $emacs as a synonym for $slave_editor.
6b24a4b7 1215use vars qw($slave_editor);
69893cff
RGS
1216*emacs = $slave_editor if $slave_editor; # May be used in afterinit()...
1217
1218=head2 READING THE RC FILE
1219
1220The debugger will read a file of initialization options if supplied. If
1221running interactively, this is C<.perldb>; if not, it's C<perldb.ini>.
1222
1223=cut
1224
1225# As noted, this test really doesn't check accurately that the debugger
1226# is running at a terminal or not.
d338d6fe 1227
98274836
JM
1228my $dev_tty = '/dev/tty';
1229 $dev_tty = 'TT:' if ($^O eq 'VMS');
6b24a4b7 1230use vars qw($rcfile);
98274836 1231if ( -e $dev_tty ) { # this is the wrong metric!
e22ea7cc
RF
1232 $rcfile = ".perldb";
1233}
69893cff
RGS
1234else {
1235 $rcfile = "perldb.ini";
d338d6fe
PP
1236}
1237
69893cff
RGS
1238=pod
1239
1240The debugger does a safety test of the file to be read. It must be owned
1241either by the current user or root, and must only be writable by the owner.
1242
1243=cut
1244
1245# This wraps a safety test around "do" to read and evaluate the init file.
1246#
055fd3a9
GS
1247# This isn't really safe, because there's a race
1248# between checking and opening. The solution is to
1249# open and fstat the handle, but then you have to read and
1250# eval the contents. But then the silly thing gets
69893cff
RGS
1251# your lexical scope, which is unfortunate at best.
1252sub safe_do {
055fd3a9
GS
1253 my $file = shift;
1254
1255 # Just exactly what part of the word "CORE::" don't you understand?
69893cff
RGS
1256 local $SIG{__WARN__};
1257 local $SIG{__DIE__};
055fd3a9 1258
e22ea7cc 1259 unless ( is_safe_file($file) ) {
69893cff 1260 CORE::warn <<EO_GRIPE;
055fd3a9
GS
1261perldb: Must not source insecure rcfile $file.
1262 You or the superuser must be the owner, and it must not
69893cff 1263 be writable by anyone but its owner.
055fd3a9 1264EO_GRIPE
69893cff
RGS
1265 return;
1266 } ## end unless (is_safe_file($file...
055fd3a9
GS
1267
1268 do $file;
1269 CORE::warn("perldb: couldn't parse $file: $@") if $@;
69893cff 1270} ## end sub safe_do
055fd3a9 1271
69893cff
RGS
1272# This is the safety test itself.
1273#
055fd3a9
GS
1274# Verifies that owner is either real user or superuser and that no
1275# one but owner may write to it. This function is of limited use
1276# when called on a path instead of upon a handle, because there are
1277# no guarantees that filename (by dirent) whose file (by ino) is
e22ea7cc 1278# eventually accessed is the same as the one tested.
055fd3a9
GS
1279# Assumes that the file's existence is not in doubt.
1280sub is_safe_file {
1281 my $path = shift;
69893cff 1282 stat($path) || return; # mysteriously vaporized
e22ea7cc 1283 my ( $dev, $ino, $mode, $nlink, $uid, $gid ) = stat(_);
055fd3a9
GS
1284
1285 return 0 if $uid != 0 && $uid != $<;
1286 return 0 if $mode & 022;
1287 return 1;
69893cff 1288} ## end sub is_safe_file
055fd3a9 1289
69893cff 1290# If the rcfile (whichever one we decided was the right one to read)
e22ea7cc
RF
1291# exists, we safely do it.
1292if ( -f $rcfile ) {
055fd3a9 1293 safe_do("./$rcfile");
69893cff 1294}
e22ea7cc 1295
69893cff 1296# If there isn't one here, try the user's home directory.
e22ea7cc 1297elsif ( defined $ENV{HOME} && -f "$ENV{HOME}/$rcfile" ) {
055fd3a9
GS
1298 safe_do("$ENV{HOME}/$rcfile");
1299}
e22ea7cc 1300
69893cff 1301# Else try the login directory.
e22ea7cc 1302elsif ( defined $ENV{LOGDIR} && -f "$ENV{LOGDIR}/$rcfile" ) {
055fd3a9 1303 safe_do("$ENV{LOGDIR}/$rcfile");
d338d6fe
PP
1304}
1305
69893cff 1306# If the PERLDB_OPTS variable has options in it, parse those out next.
e22ea7cc
RF
1307if ( defined $ENV{PERLDB_OPTS} ) {
1308 parse_options( $ENV{PERLDB_OPTS} );
d338d6fe
PP
1309}
1310
69893cff
RGS
1311=pod
1312
1313The last thing we do during initialization is determine which subroutine is
1314to be used to obtain a new terminal when a new debugger is started. Right now,
b0b54b5e 1315the debugger only handles TCP sockets, X11, OS/2, amd Mac OS X
11653f7f 1316(darwin).
69893cff
RGS
1317
1318=cut
1319
1320# Set up the get_fork_TTY subroutine to be aliased to the proper routine.
1321# Works if you're running an xterm or xterm-like window, or you're on
6fae1ad7
RF
1322# OS/2, or on Mac OS X. This may need some expansion.
1323
1324if (not defined &get_fork_TTY) # only if no routine exists
69893cff 1325{
11653f7f
JJ
1326 if ( defined $remoteport ) {
1327 # Expect an inetd-like server
1328 *get_fork_TTY = \&socket_get_fork_TTY; # to listen to us
1329 }
1330 elsif (defined $ENV{TERM} # If we know what kind
6fae1ad7
RF
1331 # of terminal this is,
1332 and $ENV{TERM} eq 'xterm' # and it's an xterm,
1333 and defined $ENV{DISPLAY} # and what display it's on,
1334 )
1335 {
1336 *get_fork_TTY = \&xterm_get_fork_TTY; # use the xterm version
1337 }
1338 elsif ( $^O eq 'os2' ) { # If this is OS/2,
1339 *get_fork_TTY = \&os2_get_fork_TTY; # use the OS/2 version
1340 }
1341 elsif ( $^O eq 'darwin' # If this is Mac OS X
1342 and defined $ENV{TERM_PROGRAM} # and we're running inside
1343 and $ENV{TERM_PROGRAM}
1344 eq 'Apple_Terminal' # Terminal.app
1345 )
1346 {
1347 *get_fork_TTY = \&macosx_get_fork_TTY; # use the Mac OS X version
1348 }
69893cff 1349} ## end if (not defined &get_fork_TTY...
e22ea7cc 1350
dbb46cec
DQ
1351# untaint $^O, which may have been tainted by the last statement.
1352# see bug [perl #24674]
e22ea7cc
RF
1353$^O =~ m/^(.*)\z/;
1354$^O = $1;
f1583d8f 1355
d12a4851 1356# Here begin the unreadable code. It needs fixing.
055fd3a9 1357
69893cff
RGS
1358=head2 RESTART PROCESSING
1359
1360This section handles the restart command. When the C<R> command is invoked, it
1361tries to capture all of the state it can into environment variables, and
1362then sets C<PERLDB_RESTART>. When we start executing again, we check to see
1363if C<PERLDB_RESTART> is there; if so, we reload all the information that
1364the R command stuffed into the environment variables.
1365
1366 PERLDB_RESTART - flag only, contains no restart data itself.
1367 PERLDB_HIST - command history, if it's available
1368 PERLDB_ON_LOAD - breakpoints set by the rc file
1369 PERLDB_POSTPONE - subs that have been loaded/not executed, and have actions
1370 PERLDB_VISITED - files that had breakpoints
1371 PERLDB_FILE_... - breakpoints for a file
1372 PERLDB_OPT - active options
1373 PERLDB_INC - the original @INC
1374 PERLDB_PRETYPE - preprompt debugger actions
1375 PERLDB_PRE - preprompt Perl code
1376 PERLDB_POST - post-prompt Perl code
1377 PERLDB_TYPEAHEAD - typeahead captured by readline()
1378
1379We chug through all these variables and plug the values saved in them
1380back into the appropriate spots in the debugger.
1381
1382=cut
1383
6b24a4b7
SF
1384use vars qw(@hist @truehist %postponed_file @typeahead);
1385
e22ea7cc
RF
1386if ( exists $ENV{PERLDB_RESTART} ) {
1387
69893cff 1388 # We're restarting, so we don't need the flag that says to restart anymore.
e22ea7cc
RF
1389 delete $ENV{PERLDB_RESTART};
1390
1391 # $restart = 1;
1392 @hist = get_list('PERLDB_HIST');
1393 %break_on_load = get_list("PERLDB_ON_LOAD");
1394 %postponed = get_list("PERLDB_POSTPONE");
69893cff 1395
2cbb2ee1
RGS
1396 share(@hist);
1397 share(@truehist);
1398 share(%break_on_load);
1399 share(%postponed);
1400
69893cff 1401 # restore breakpoints/actions
e22ea7cc 1402 my @had_breakpoints = get_list("PERLDB_VISITED");
bdba49ad
SF
1403 for my $file_idx ( 0 .. $#had_breakpoints ) {
1404 my $filename = $had_breakpoints[$file_idx];
1405 my %pf = get_list("PERLDB_FILE_$file_idx");
1406 $postponed_file{ $filename } = \%pf if %pf;
1407 my @lines = sort {$a <=> $b} keys(%pf);
1408 my @enabled_statuses = get_list("PERLDB_FILE_ENABLED_$file_idx");
1409 for my $line_idx (0 .. $#lines) {
1410 _set_breakpoint_enabled_status(
1411 $filename,
1412 $lines[$line_idx],
1413 ($enabled_statuses[$line_idx] ? 1 : ''),
1414 );
1415 }
e22ea7cc 1416 }
69893cff
RGS
1417
1418 # restore options
e22ea7cc
RF
1419 my %opt = get_list("PERLDB_OPT");
1420 my ( $opt, $val );
1421 while ( ( $opt, $val ) = each %opt ) {
1422 $val =~ s/[\\\']/\\$1/g;
1423 parse_options("$opt'$val'");
1424 }
69893cff
RGS
1425
1426 # restore original @INC
e22ea7cc
RF
1427 @INC = get_list("PERLDB_INC");
1428 @ini_INC = @INC;
1429
1430 # return pre/postprompt actions and typeahead buffer
1431 $pretype = [ get_list("PERLDB_PRETYPE") ];
1432 $pre = [ get_list("PERLDB_PRE") ];
1433 $post = [ get_list("PERLDB_POST") ];
1434 @typeahead = get_list( "PERLDB_TYPEAHEAD", @typeahead );
69893cff
RGS
1435} ## end if (exists $ENV{PERLDB_RESTART...
1436
1437=head2 SETTING UP THE TERMINAL
1438
1439Now, we'll decide how the debugger is going to interact with the user.
1440If there's no TTY, we set the debugger to run non-stop; there's not going
1441to be anyone there to enter commands.
1442
1443=cut
54d04a52 1444
6b24a4b7
SF
1445use vars qw($notty $runnonstop $console $tty $LINEINFO);
1446use vars qw($lineinfo $doccmd);
1447
d338d6fe 1448if ($notty) {
69893cff 1449 $runnonstop = 1;
2cbb2ee1 1450 share($runnonstop);
69893cff 1451}
d12a4851 1452
69893cff
RGS
1453=pod
1454
1455If there is a TTY, we have to determine who it belongs to before we can
1456proceed. If this is a slave editor or graphical debugger (denoted by
1457the first command-line switch being '-emacs'), we shift this off and
1458set C<$rl> to 0 (XXX ostensibly to do straight reads).
1459
1460=cut
1461
1462else {
e22ea7cc 1463
69893cff
RGS
1464 # Is Perl being run from a slave editor or graphical debugger?
1465 # If so, don't use readline, and set $slave_editor = 1.
e22ea7cc
RF
1466 $slave_editor =
1467 ( ( defined $main::ARGV[0] ) and ( $main::ARGV[0] eq '-emacs' ) );
1468 $rl = 0, shift(@main::ARGV) if $slave_editor;
1469
1470 #require Term::ReadLine;
d12a4851 1471
69893cff
RGS
1472=pod
1473
1474We then determine what the console should be on various systems:
1475
1476=over 4
1477
1478=item * Cygwin - We use C<stdin> instead of a separate device.
1479
1480=cut
1481
e22ea7cc
RF
1482 if ( $^O eq 'cygwin' ) {
1483
69893cff
RGS
1484 # /dev/tty is binary. use stdin for textmode
1485 undef $console;
1486 }
1487
1488=item * Unix - use C</dev/tty>.
1489
1490=cut
1491
e22ea7cc 1492 elsif ( -e "/dev/tty" ) {
69893cff
RGS
1493 $console = "/dev/tty";
1494 }
1495
1496=item * Windows or MSDOS - use C<con>.
1497
1498=cut
1499
e22ea7cc 1500 elsif ( $^O eq 'dos' or -e "con" or $^O eq 'MSWin32' ) {
69893cff
RGS
1501 $console = "con";
1502 }
1503
69893cff
RGS
1504=item * VMS - use C<sys$command>.
1505
1506=cut
1507
1508 else {
e22ea7cc 1509
69893cff
RGS
1510 # everything else is ...
1511 $console = "sys\$command";
d12a4851 1512 }
69893cff
RGS
1513
1514=pod
1515
1516=back
1517
1518Several other systems don't use a specific console. We C<undef $console>
1519for those (Windows using a slave editor/graphical debugger, NetWare, OS/2
1520with a slave editor, Epoc).
1521
1522=cut
d12a4851 1523
e22ea7cc
RF
1524 if ( ( $^O eq 'MSWin32' ) and ( $slave_editor or defined $ENV{EMACS} ) ) {
1525
69893cff 1526 # /dev/tty is binary. use stdin for textmode
e22ea7cc
RF
1527 $console = undef;
1528 }
1529
1530 if ( $^O eq 'NetWare' ) {
d12a4851 1531
69893cff
RGS
1532 # /dev/tty is binary. use stdin for textmode
1533 $console = undef;
1534 }
d12a4851 1535
69893cff
RGS
1536 # In OS/2, we need to use STDIN to get textmode too, even though
1537 # it pretty much looks like Unix otherwise.
e22ea7cc
RF
1538 if ( defined $ENV{OS2_SHELL} and ( $slave_editor or $ENV{WINDOWID} ) )
1539 { # In OS/2
1540 $console = undef;
1541 }
1542
1543 # EPOC also falls into the 'got to use STDIN' camp.
1544 if ( $^O eq 'epoc' ) {
1545 $console = undef;
1546 }
d12a4851 1547
69893cff
RGS
1548=pod
1549
1550If there is a TTY hanging around from a parent, we use that as the console.
1551
1552=cut
1553
e22ea7cc 1554 $console = $tty if defined $tty;
d12a4851 1555
69893cff
RGS
1556=head2 SOCKET HANDLING
1557
1558The debugger is capable of opening a socket and carrying out a debugging
1559session over the socket.
1560
1561If C<RemotePort> was defined in the options, the debugger assumes that it
1562should try to start a debugging session on that port. It builds the socket
1563and then tries to connect the input and output filehandles to it.
1564
1565=cut
1566
1567 # Handle socket stuff.
e22ea7cc
RF
1568
1569 if ( defined $remoteport ) {
1570
69893cff
RGS
1571 # If RemotePort was defined in the options, connect input and output
1572 # to the socket.
11653f7f 1573 $IN = $OUT = connect_remoteport();
69893cff
RGS
1574 } ## end if (defined $remoteport)
1575
1576=pod
1577
1578If no C<RemotePort> was defined, and we want to create a TTY on startup,
1579this is probably a situation where multiple debuggers are running (for example,
1580a backticked command that starts up another debugger). We create a new IN and
1581OUT filehandle, and do the necessary mojo to create a new TTY if we know how
1582and if we can.
1583
1584=cut
1585
1586 # Non-socket.
1587 else {
e22ea7cc 1588
69893cff
RGS
1589 # Two debuggers running (probably a system or a backtick that invokes
1590 # the debugger itself under the running one). create a new IN and OUT
e22ea7cc 1591 # filehandle, and do the necessary mojo to create a new tty if we
69893cff 1592 # know how, and we can.
e22ea7cc
RF
1593 create_IN_OUT(4) if $CreateTTY & 4;
1594 if ($console) {
1595
69893cff 1596 # If we have a console, check to see if there are separate ins and
cd1191f1 1597 # outs to open. (They are assumed identical if not.)
69893cff 1598
e22ea7cc
RF
1599 my ( $i, $o ) = split /,/, $console;
1600 $o = $i unless defined $o;
69893cff 1601
69893cff 1602 # read/write on in, or just read, or read on STDIN.
e22ea7cc
RF
1603 open( IN, "+<$i" )
1604 || open( IN, "<$i" )
1605 || open( IN, "<&STDIN" );
1606
69893cff
RGS
1607 # read/write/create/clobber out, or write/create/clobber out,
1608 # or merge with STDERR, or merge with STDOUT.
e22ea7cc
RF
1609 open( OUT, "+>$o" )
1610 || open( OUT, ">$o" )
1611 || open( OUT, ">&STDERR" )
1612 || open( OUT, ">&STDOUT" ); # so we don't dongle stdout
1613
1614 } ## end if ($console)
1615 elsif ( not defined $console ) {
1616
1617 # No console. Open STDIN.
1618 open( IN, "<&STDIN" );
1619
1620 # merge with STDERR, or with STDOUT.
1621 open( OUT, ">&STDERR" )
1622 || open( OUT, ">&STDOUT" ); # so we don't dongle stdout
1623 $console = 'STDIN/OUT';
69893cff
RGS
1624 } ## end elsif (not defined $console)
1625
1626 # Keep copies of the filehandles so that when the pager runs, it
1627 # can close standard input without clobbering ours.
e22ea7cc
RF
1628 $IN = \*IN, $OUT = \*OUT if $console or not defined $console;
1629 } ## end elsif (from if(defined $remoteport))
1630
1631 # Unbuffer DB::OUT. We need to see responses right away.
1632 my $previous = select($OUT);
1633 $| = 1; # for DB::OUT
1634 select($previous);
1635
1636 # Line info goes to debugger output unless pointed elsewhere.
1637 # Pointing elsewhere makes it possible for slave editors to
1638 # keep track of file and position. We have both a filehandle
1639 # and a I/O description to keep track of.
1640 $LINEINFO = $OUT unless defined $LINEINFO;
1641 $lineinfo = $console unless defined $lineinfo;
2cbb2ee1
RGS
1642 # share($LINEINFO); # <- unable to share globs
1643 share($lineinfo); #
e22ea7cc 1644
69893cff
RGS
1645=pod
1646
1647To finish initialization, we show the debugger greeting,
1648and then call the C<afterinit()> subroutine if there is one.
1649
1650=cut
d12a4851 1651
e22ea7cc
RF
1652 # Show the debugger greeting.
1653 $header =~ s/.Header: ([^,]+),v(\s+\S+\s+\S+).*$/$1$2/;
1654 unless ($runnonstop) {
1655 local $\ = '';
1656 local $, = '';
1657 if ( $term_pid eq '-1' ) {
1658 print $OUT "\nDaughter DB session started...\n";
1659 }
1660 else {
1661 print $OUT "\nLoading DB routines from $header\n";
1662 print $OUT (
1663 "Editor support ",
1664 $slave_editor ? "enabled" : "available", ".\n"
1665 );
1666 print $OUT
1f874cb6 1667"\nEnter h or 'h h' for help, or '$doccmd perldebug' for more help.\n\n";
69893cff
RGS
1668 } ## end else [ if ($term_pid eq '-1')
1669 } ## end unless ($runnonstop)
1670} ## end else [ if ($notty)
1671
1672# XXX This looks like a bug to me.
1673# Why copy to @ARGS and then futz with @args?
d338d6fe 1674@ARGS = @ARGV;
6b24a4b7 1675# for (@args) {
69893cff
RGS
1676 # Make sure backslashes before single quotes are stripped out, and
1677 # keep args unless they are numeric (XXX why?)
e22ea7cc
RF
1678 # s/\'/\\\'/g; # removed while not justified understandably
1679 # s/(.*)/'$1'/ unless /^-?[\d.]+$/; # ditto
6b24a4b7 1680# }
d338d6fe 1681
e22ea7cc 1682# If there was an afterinit() sub defined, call it. It will get
69893cff 1683# executed in our scope, so it can fiddle with debugger globals.
e22ea7cc 1684if ( defined &afterinit ) { # May be defined in $rcfile
69893cff 1685 &afterinit();
d338d6fe 1686}
e22ea7cc 1687
69893cff 1688# Inform us about "Stack dump during die enabled ..." in dieLevel().
6b24a4b7
SF
1689use vars qw($I_m_init);
1690
43aed9ee
IZ
1691$I_m_init = 1;
1692
d338d6fe
PP
1693############################################################ Subroutines
1694
69893cff
RGS
1695=head1 SUBROUTINES
1696
1697=head2 DB
1698
1699This gigantic subroutine is the heart of the debugger. Called before every
1700statement, its job is to determine if a breakpoint has been reached, and
1701stop if so; read commands from the user, parse them, and execute
b468dcb6 1702them, and then send execution off to the next statement.
69893cff
RGS
1703
1704Note that the order in which the commands are processed is very important;
1705some commands earlier in the loop will actually alter the C<$cmd> variable
be9a9b1d 1706to create other commands to be executed later. This is all highly I<optimized>
69893cff
RGS
1707but can be confusing. Check the comments for each C<$cmd ... && do {}> to
1708see what's happening in any given command.
1709
1710=cut
1711
6b24a4b7
SF
1712use vars qw(
1713 $action
1714 %alias
1715 $cmd
1716 $doret
1717 $fall_off_end
1718 $file
1719 $filename_ini
1720 $finished
1721 %had_breakpoints
1722 $incr
1723 $laststep
1724 $level
1725 $max
1726 @old_watch
1727 $package
1728 $rc
1729 $sh
1730 @stack
1731 $stack_depth
1732 @to_watch
1733 $try
2c247e84 1734 $end
6b24a4b7
SF
1735);
1736
d338d6fe 1737sub DB {
69893cff 1738
2cbb2ee1
RGS
1739 # lock the debugger and get the thread id for the prompt
1740 lock($DBGR);
1741 my $tid;
6b24a4b7
SF
1742 my $position;
1743 my ($prefix, $after, $infix);
1744 my $pat;
6b24a4b7 1745
2cbb2ee1 1746 if ($ENV{PERL5DB_THREADED}) {
878090d5 1747 $tid = eval { "[".threads->tid."]" };
2cbb2ee1
RGS
1748 }
1749
69893cff 1750 # Check for whether we should be running continuously or not.
36477c24 1751 # _After_ the perl program is compiled, $single is set to 1:
e22ea7cc
RF
1752 if ( $single and not $second_time++ ) {
1753
69893cff 1754 # Options say run non-stop. Run until we get an interrupt.
e22ea7cc
RF
1755 if ($runnonstop) { # Disable until signal
1756 # If there's any call stack in place, turn off single
1757 # stepping into subs throughout the stack.
2c247e84 1758 for my $i (0 .. $stack_depth) {
72d7d80d 1759 $stack[ $i ] &= ~1;
e22ea7cc
RF
1760 }
1761
69893cff 1762 # And we are now no longer in single-step mode.
e22ea7cc 1763 $single = 0;
69893cff
RGS
1764
1765 # If we simply returned at this point, we wouldn't get
1766 # the trace info. Fall on through.
e22ea7cc 1767 # return;
69893cff
RGS
1768 } ## end if ($runnonstop)
1769
e22ea7cc
RF
1770 elsif ($ImmediateStop) {
1771
1772 # We are supposed to stop here; XXX probably a break.
1773 $ImmediateStop = 0; # We've processed it; turn it off
1774 $signal = 1; # Simulate an interrupt to force
1775 # us into the command loop
69893cff
RGS
1776 }
1777 } ## end if ($single and not $second_time...
1778
1779 # If we're in single-step mode, or an interrupt (real or fake)
1780 # has occurred, turn off non-stop mode.
1781 $runnonstop = 0 if $single or $signal;
1782
1783 # Preserve current values of $@, $!, $^E, $,, $/, $\, $^W.
1784 # The code being debugged may have altered them.
d338d6fe 1785 &save;
69893cff
RGS
1786
1787 # Since DB::DB gets called after every line, we can use caller() to
1788 # figure out where we last were executing. Sneaky, eh? This works because
e22ea7cc 1789 # caller is returning all the extra information when called from the
69893cff 1790 # debugger.
e22ea7cc 1791 local ( $package, $filename, $line ) = caller;
6b24a4b7 1792 $filename_ini = $filename;
69893cff
RGS
1793
1794 # set up the context for DB::eval, so it can properly execute
1795 # code on behalf of the user. We add the package in so that the
1796 # code is eval'ed in the proper package (not in the debugger!).
6b24a4b7 1797 local $usercontext = _calc_usercontext($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 1802
69893cff 1803 # Last line in the program.
55783941 1804 $max = $#dbline;
69893cff
RGS
1805
1806 # if we have something here, see if we should break.
e22ea7cc 1807 {
72d7d80d
SF
1808 # $stop is lexical and local to this block - $action on the other hand
1809 # is global.
1810 my $stop;
e22ea7cc 1811
72d7d80d
SF
1812 if ( $dbline{$line}
1813 && _is_breakpoint_enabled($filename, $line)
1814 && (( $stop, $action ) = split( /\0/, $dbline{$line} ) ) )
1815 {
e22ea7cc 1816
72d7d80d
SF
1817 # Stop if the stop criterion says to just stop.
1818 if ( $stop eq '1' ) {
1819 $signal |= 1;
5d5d9ea3 1820 }
72d7d80d
SF
1821
1822 # It's a conditional stop; eval it in the user's context and
1823 # see if we should stop. If so, remove the one-time sigil.
1824 elsif ($stop) {
1825 $evalarg = "\$DB::signal |= 1 if do {$stop}";
1826 &eval;
1827 # If the breakpoint is temporary, then delete its enabled status.
1828 if ($dbline{$line} =~ s/;9($|\0)/$1/) {
1829 _cancel_breakpoint_temp_enabled_status($filename, $line);
1830 }
1831 }
1832 } ## end if ($dbline{$line} && ...
1833 }
69893cff
RGS
1834
1835 # Preserve the current stop-or-not, and see if any of the W
1836 # (watch expressions) has changed.
36477c24 1837 my $was_signal = $signal;
69893cff
RGS
1838
1839 # If we have any watch expressions ...
e22ea7cc 1840 if ( $trace & 2 ) {
2c247e84 1841 for my $n (0 .. $#to_watch) {
e22ea7cc
RF
1842 $evalarg = $to_watch[$n];
1843 local $onetimeDump; # Tell DB::eval() to not output results
69893cff
RGS
1844
1845 # Fix context DB::eval() wants to return an array, but
1846 # we need a scalar here.
e22ea7cc
RF
1847 my ($val) = join( "', '", &eval );
1848 $val = ( ( defined $val ) ? "'$val'" : 'undef' );
69893cff
RGS
1849
1850 # Did it change?
e22ea7cc
RF
1851 if ( $val ne $old_watch[$n] ) {
1852
69893cff 1853 # Yep! Show the difference, and fake an interrupt.
e22ea7cc
RF
1854 $signal = 1;
1855 print $OUT <<EOP;
405ff068 1856Watchpoint $n:\t$to_watch[$n] changed:
69893cff
RGS
1857 old value:\t$old_watch[$n]
1858 new value:\t$val
6027b9a3 1859EOP
e22ea7cc 1860 $old_watch[$n] = $val;
69893cff 1861 } ## end if ($val ne $old_watch...
2c247e84 1862 } ## end for my $n (0 ..
69893cff
RGS
1863 } ## end if ($trace & 2)
1864
1865=head2 C<watchfunction()>
1866
1867C<watchfunction()> is a function that can be defined by the user; it is a
1868function which will be run on each entry to C<DB::DB>; it gets the
1869current package, filename, and line as its parameters.
1870
1871The watchfunction can do anything it likes; it is executing in the
1872debugger's context, so it has access to all of the debugger's internal
1873data structures and functions.
1874
1875C<watchfunction()> can control the debugger's actions. Any of the following
1876will cause the debugger to return control to the user's program after
1877C<watchfunction()> executes:
1878
1879=over 4
1880
be9a9b1d
AT
1881=item *
1882
1883Returning a false value from the C<watchfunction()> itself.
1884
1885=item *
1886
1887Altering C<$single> to a false value.
1888
1889=item *
69893cff 1890
be9a9b1d 1891Altering C<$signal> to a false value.
69893cff 1892
be9a9b1d 1893=item *
69893cff 1894
be9a9b1d 1895Turning off the C<4> bit in C<$trace> (this also disables the
69893cff
RGS
1896check for C<watchfunction()>. This can be done with
1897
1898 $trace &= ~4;
1899
1900=back
1901
1902=cut
1903
e22ea7cc 1904 # If there's a user-defined DB::watchfunction, call it with the
69893cff
RGS
1905 # current package, filename, and line. The function executes in
1906 # the DB:: package.
e22ea7cc
RF
1907 if ( $trace & 4 ) { # User-installed watch
1908 return
1909 if watchfunction( $package, $filename, $line )
1910 and not $single
1911 and not $was_signal
1912 and not( $trace & ~4 );
69893cff
RGS
1913 } ## end if ($trace & 4)
1914
e22ea7cc 1915 # Pick up any alteration to $signal in the watchfunction, and
69893cff 1916 # turn off the signal now.
6027b9a3 1917 $was_signal = $signal;
69893cff
RGS
1918 $signal = 0;
1919
1920=head2 GETTING READY TO EXECUTE COMMANDS
1921
1922The debugger decides to take control if single-step mode is on, the
1923C<t> command was entered, or the user generated a signal. If the program
1924has fallen off the end, we set things up so that entering further commands
1925won't cause trouble, and we say that the program is over.
1926
1927=cut
1928
8dc67a69
SF
1929 # Make sure that we always print if asked for explicitly regardless
1930 # of $trace_to_depth .
1931 my $explicit_stop = ($single || $was_signal);
1932
69893cff
RGS
1933 # Check to see if we should grab control ($single true,
1934 # trace set appropriately, or we got a signal).
8dc67a69 1935 if ( $explicit_stop || ( $trace & 1 ) ) {
e22ea7cc 1936
69893cff 1937 # Yes, grab control.
e22ea7cc
RF
1938 if ($slave_editor) {
1939
69893cff 1940 # Tell the editor to update its position.
e22ea7cc
RF
1941 $position = "\032\032$filename:$line:0\n";
1942 print_lineinfo($position);
1943 }
69893cff
RGS
1944
1945=pod
1946
1947Special check: if we're in package C<DB::fake>, we've gone through the
1948C<END> block at least once. We set up everything so that we can continue
1949to enter commands and have a valid context to be in.
1950
1951=cut
1952
e22ea7cc 1953 elsif ( $package eq 'DB::fake' ) {
69893cff 1954
69893cff 1955 # Fallen off the end already.
e22ea7cc
RF
1956 $term || &setterm;
1957 print_help(<<EOP);
405ff068 1958Debugged program terminated. Use B<q> to quit or B<R> to restart,
6b27b0a0
BD
1959 use B<o> I<inhibit_exit> to avoid stopping after program termination,
1960 B<h q>, B<h R> or B<h o> to get additional info.
405ff068 1961EOP
e22ea7cc 1962
69893cff 1963 # Set the DB::eval context appropriately.
e22ea7cc 1964 $package = 'main';
6b24a4b7 1965 $usercontext = _calc_usercontext($package);
69893cff 1966 } ## end elsif ($package eq 'DB::fake')
e219e2fb 1967
69893cff 1968=pod
e219e2fb 1969
69893cff
RGS
1970If the program hasn't finished executing, we scan forward to the
1971next executable line, print that out, build the prompt from the file and line
1972number information, and print that.
e219e2fb 1973
69893cff
RGS
1974=cut
1975
e22ea7cc
RF
1976 else {
1977
8dc67a69 1978
69893cff
RGS
1979 # Still somewhere in the midst of execution. Set up the
1980 # debugger prompt.
1981 $sub =~ s/\'/::/; # Swap Perl 4 package separators (') to
e22ea7cc 1982 # Perl 5 ones (sorry, we don't print Klingon
69893cff
RGS
1983 #module names)
1984
6b24a4b7 1985 $prefix = $sub =~ /::/ ? "" : ($package . '::');
e22ea7cc
RF
1986 $prefix .= "$sub($filename:";
1987 $after = ( $dbline[$line] =~ /\n$/ ? '' : "\n" );
69893cff
RGS
1988
1989 # Break up the prompt if it's really long.
e22ea7cc
RF
1990 if ( length($prefix) > 30 ) {
1991 $position = "$prefix$line):\n$line:\t$dbline[$line]$after";
1992 $prefix = "";
1993 $infix = ":\t";
1994 }
1995 else {
1996 $infix = "):\t";
1997 $position = "$prefix$line$infix$dbline[$line]$after";
1998 }
69893cff
RGS
1999
2000 # Print current line info, indenting if necessary.
e22ea7cc
RF
2001 if ($frame) {
2002 print_lineinfo( ' ' x $stack_depth,
2003 "$line:\t$dbline[$line]$after" );
2004 }
2005 else {
8dc67a69 2006 depth_print_lineinfo($explicit_stop, $position);
e22ea7cc 2007 }
69893cff
RGS
2008
2009 # Scan forward, stopping at either the end or the next
2010 # unbreakable line.
72d7d80d 2011 for ( my $i = $line + 1 ; $i <= $max && $dbline[$i] == 0 ; ++$i )
e22ea7cc 2012 { #{ vi
69893cff
RGS
2013
2014 # Drop out on null statements, block closers, and comments.
2015 last if $dbline[$i] =~ /^\s*[\;\}\#\n]/;
2016
2017 # Drop out if the user interrupted us.
2018 last if $signal;
2019
2020 # Append a newline if the line doesn't have one. Can happen
2021 # in eval'ed text, for instance.
e22ea7cc 2022 $after = ( $dbline[$i] =~ /\n$/ ? '' : "\n" );
69893cff
RGS
2023
2024 # Next executable line.
6b24a4b7 2025 my $incr_pos = "$prefix$i$infix$dbline[$i]$after";
69893cff
RGS
2026 $position .= $incr_pos;
2027 if ($frame) {
e22ea7cc 2028
69893cff 2029 # Print it indented if tracing is on.
e22ea7cc
RF
2030 print_lineinfo( ' ' x $stack_depth,
2031 "$i:\t$dbline[$i]$after" );
69893cff
RGS
2032 }
2033 else {
8dc67a69 2034 depth_print_lineinfo($explicit_stop, $incr_pos);
69893cff 2035 }
72d7d80d 2036 } ## end for ($i = $line + 1 ; $i...
69893cff
RGS
2037 } ## end else [ if ($slave_editor)
2038 } ## end if ($single || ($trace...
2039
2040=pod
2041
2042If there's an action to be executed for the line we stopped at, execute it.
2043If there are any preprompt actions, execute those as well.
e219e2fb
RF
2044
2045=cut
2046
69893cff
RGS
2047 # If there's an action, do it now.
2048 $evalarg = $action, &eval if $action;
e219e2fb 2049
69893cff
RGS
2050 # Are we nested another level (e.g., did we evaluate a function
2051 # that had a breakpoint in it at the debugger prompt)?
e22ea7cc
RF
2052 if ( $single || $was_signal ) {
2053
69893cff 2054 # Yes, go down a level.
e22ea7cc 2055 local $level = $level + 1;
69893cff
RGS
2056
2057 # Do any pre-prompt actions.
e22ea7cc
RF
2058 foreach $evalarg (@$pre) {
2059 &eval;
2060 }
69893cff
RGS
2061
2062 # Complain about too much recursion if we passed the limit.
e22ea7cc 2063 print $OUT $stack_depth . " levels deep in subroutine calls!\n"
69893cff
RGS
2064 if $single & 4;
2065
2066 # The line we're currently on. Set $incr to -1 to stay here
2067 # until we get a command that tells us to advance.
e22ea7cc
RF
2068 $start = $line;
2069 $incr = -1; # for backward motion.
69893cff
RGS
2070
2071 # Tack preprompt debugger actions ahead of any actual input.
e22ea7cc 2072 @typeahead = ( @$pretype, @typeahead );
69893cff
RGS
2073
2074=head2 WHERE ARE WE?
2075
2076XXX Relocate this section?
2077
2078The debugger normally shows the line corresponding to the current line of
2079execution. Sometimes, though, we want to see the next line, or to move elsewhere
2080in the file. This is done via the C<$incr>, C<$start>, and C<$max> variables.
2081
be9a9b1d
AT
2082C<$incr> controls by how many lines the I<current> line should move forward
2083after a command is executed. If set to -1, this indicates that the I<current>
69893cff
RGS
2084line shouldn't change.
2085
be9a9b1d 2086C<$start> is the I<current> line. It is used for things like knowing where to
69893cff
RGS
2087move forwards or backwards from when doing an C<L> or C<-> command.
2088
2089C<$max> tells the debugger where the last line of the current file is. It's
2090used to terminate loops most often.
2091
2092=head2 THE COMMAND LOOP
2093
2094Most of C<DB::DB> is actually a command parsing and dispatch loop. It comes
2095in two parts:
2096
2097=over 4
2098
be9a9b1d
AT
2099=item *
2100
2101The outer part of the loop, starting at the C<CMD> label. This loop
69893cff
RGS
2102reads a command and then executes it.
2103
be9a9b1d
AT
2104=item *
2105
2106The inner part of the loop, starting at the C<PIPE> label. This part
69893cff
RGS
2107is wholly contained inside the C<CMD> block and only executes a command.
2108Used to handle commands running inside a pager.
2109
2110=back
2111
2112So why have two labels to restart the loop? Because sometimes, it's easier to
2113have a command I<generate> another command and then re-execute the loop to do
2114the new command. This is faster, but perhaps a bit more convoluted.
2115
2116=cut
2117
2118 # The big command dispatch loop. It keeps running until the
2119 # user yields up control again.
2120 #
2121 # If we have a terminal for input, and we get something back
2122 # from readline(), keep on processing.
6b24a4b7
SF
2123 my $piped;
2124 my $selected;
2125
e22ea7cc
RF
2126 CMD:
2127 while (
2128
69893cff 2129 # We have a terminal, or can get one ...
e22ea7cc
RF
2130 ( $term || &setterm ),
2131
69893cff 2132 # ... and it belogs to this PID or we get one for this PID ...
e22ea7cc
RF
2133 ( $term_pid == $$ or resetterm(1) ),
2134
69893cff 2135 # ... and we got a line of command input ...
e22ea7cc
RF
2136 defined(
2137 $cmd = &readline(
2cbb2ee1 2138 "$pidprompt $tid DB"
e22ea7cc
RF
2139 . ( '<' x $level )
2140 . ( $#hist + 1 )
2141 . ( '>' x $level ) . " "
69893cff
RGS
2142 )
2143 )
2144 )
2145 {
e22ea7cc 2146
2cbb2ee1 2147 share($cmd);
69893cff
RGS
2148 # ... try to execute the input as debugger commands.
2149
2150 # Don't stop running.
2151 $single = 0;
2152
2153 # No signal is active.
2154 $signal = 0;
2155
2156 # Handle continued commands (ending with \):
3d7a2a93 2157 if ($cmd =~ s/\\\z/\n/) {
e22ea7cc
RF
2158 $cmd .= &readline(" cont: ");
2159 redo CMD;
3d7a2a93 2160 }
69893cff
RGS
2161
2162=head4 The null command
2163
be9a9b1d 2164A newline entered by itself means I<re-execute the last command>. We grab the
69893cff
RGS
2165command out of C<$laststep> (where it was recorded previously), and copy it
2166back into C<$cmd> to be executed below. If there wasn't any previous command,
2167we'll do nothing below (no command will match). If there was, we also save it
2168in the command history and fall through to allow the command parsing to pick
2169it up.
2170
2171=cut
2172
2173 # Empty input means repeat the last command.
e22ea7cc
RF
2174 $cmd =~ /^$/ && ( $cmd = $laststep );
2175 chomp($cmd); # get rid of the annoying extra newline
2176 push( @hist, $cmd ) if length($cmd) > 1;
2177 push( @truehist, $cmd );
2cbb2ee1
RGS
2178 share(@hist);
2179 share(@truehist);
e22ea7cc
RF
2180
2181 # This is a restart point for commands that didn't arrive
2182 # via direct user input. It allows us to 'redo PIPE' to
2183 # re-execute command processing without reading a new command.
69893cff 2184 PIPE: {
e22ea7cc
RF
2185 $cmd =~ s/^\s+//s; # trim annoying leading whitespace
2186 $cmd =~ s/\s+$//s; # trim annoying trailing whitespace
6b24a4b7 2187 my ($i) = split( /\s+/, $cmd );
69893cff
RGS
2188
2189=head3 COMMAND ALIASES
2190
2191The debugger can create aliases for commands (these are stored in the
2192C<%alias> hash). Before a command is executed, the command loop looks it up
2193in the alias hash and substitutes the contents of the alias for the command,
2194completely replacing it.
2195
2196=cut
2197
2198 # See if there's an alias for the command, and set it up if so.
e22ea7cc
RF
2199 if ( $alias{$i} ) {
2200
69893cff
RGS
2201 # Squelch signal handling; we want to keep control here
2202 # if something goes loco during the alias eval.
2203 local $SIG{__DIE__};
2204 local $SIG{__WARN__};
2205
2206 # This is a command, so we eval it in the DEBUGGER's
2207 # scope! Otherwise, we can't see the special debugger
2208 # variables, or get to the debugger's subs. (Well, we
2209 # _could_, but why make it even more complicated?)
2210 eval "\$cmd =~ $alias{$i}";
2211 if ($@) {
2212 local $\ = '';
1f874cb6 2213 print $OUT "Couldn't evaluate '$i' alias: $@";
69893cff
RGS
2214 next CMD;
2215 }
2216 } ## end if ($alias{$i})
2217
2218=head3 MAIN-LINE COMMANDS
2219
2220All of these commands work up to and after the program being debugged has
2221terminated.
2222
2223=head4 C<q> - quit
2224
2225Quit the debugger. This entails setting the C<$fall_off_end> flag, so we don't
2226try to execute further, cleaning any restart-related stuff out of the
2227environment, and executing with the last value of C<$?>.
2228
2229=cut
2230
3d7a2a93 2231 if ($cmd eq 'q') {
69893cff
RGS
2232 $fall_off_end = 1;
2233 clean_ENV();
2234 exit $?;
3d7a2a93 2235 }
69893cff 2236
611272bb 2237=head4 C<t> - trace [n]
69893cff
RGS
2238
2239Turn tracing on or off. Inverts the appropriate bit in C<$trace> (q.v.).
611272bb 2240If level is specified, set C<$trace_to_depth>.
69893cff
RGS
2241
2242=cut
2243
3d7a2a93 2244 if (my ($levels) = $cmd =~ /\At(?:\s+(\d+))?\z/) {
e22ea7cc
RF
2245 $trace ^= 1;
2246 local $\ = '';
611272bb 2247 $trace_to_depth = $levels ? $stack_depth + $levels : 1E9;
e22ea7cc 2248 print $OUT "Trace = "
611272bb
PS
2249 . ( ( $trace & 1 )
2250 ? ( $levels ? "on (to level $trace_to_depth)" : "on" )
2251 : "off" ) . "\n";
e22ea7cc 2252 next CMD;
3d7a2a93 2253 }
69893cff
RGS
2254
2255=head4 C<S> - list subroutines matching/not matching a pattern
2256
2257Walks through C<%sub>, checking to see whether or not to print the name.
2258
2259=cut
2260
e22ea7cc 2261 $cmd =~ /^S(\s+(!)?(.+))?$/ && do {
69893cff 2262
6b24a4b7
SF
2263 my $Srev = defined $2; # Reverse scan?
2264 my $Spatt = $3; # The pattern (if any) to use.
2265 my $Snocheck = !defined $1; # No args - print all subs.
69893cff
RGS
2266
2267 # Need to make these sane here.
e22ea7cc
RF
2268 local $\ = '';
2269 local $, = '';
69893cff
RGS
2270
2271 # Search through the debugger's magical hash of subs.
2272 # If $nocheck is true, just print the sub name.
2273 # Otherwise, check it against the pattern. We then use
2274 # the XOR trick to reverse the condition as required.
e22ea7cc
RF
2275 foreach $subname ( sort( keys %sub ) ) {
2276 if ( $Snocheck or $Srev ^ ( $subname =~ /$Spatt/ ) ) {
2277 print $OUT $subname, "\n";
2278 }
2279 }
2280 next CMD;
2281 };
69893cff
RGS
2282
2283=head4 C<X> - list variables in current package
2284
2285Since the C<V> command actually processes this, just change this to the
2286appropriate C<V> command and fall through.
2287
2288=cut
2289
e22ea7cc 2290 $cmd =~ s/^X\b/V $package/;
69893cff
RGS
2291
2292=head4 C<V> - list variables
2293
2294Uses C<dumpvar.pl> to dump out the current values for selected variables.
2295
2296=cut
2297
2298 # Bare V commands get the currently-being-debugged package
2299 # added.
e22ea7cc
RF
2300 $cmd =~ /^V$/ && do {
2301 $cmd = "V $package";
2302 };
69893cff
RGS
2303
2304 # V - show variables in package.
2305 $cmd =~ /^V\b\s*(\S+)\s*(.*)/ && do {
e22ea7cc 2306
69893cff
RGS
2307 # Save the currently selected filehandle and
2308 # force output to debugger's filehandle (dumpvar
2309 # just does "print" for output).
6b24a4b7 2310 my $savout = select($OUT);
69893cff
RGS
2311
2312 # Grab package name and variables to dump.
e22ea7cc 2313 $packname = $1;
6b24a4b7 2314 my @vars = split( ' ', $2 );
69893cff
RGS
2315
2316 # If main::dumpvar isn't here, get it.
e81465be 2317 do 'dumpvar.pl' || die $@ unless defined &main::dumpvar;
e22ea7cc
RF
2318 if ( defined &main::dumpvar ) {
2319
69893cff
RGS
2320 # We got it. Turn off subroutine entry/exit messages
2321 # for the moment, along with return values.
e22ea7cc
RF
2322 local $frame = 0;
2323 local $doret = -2;
69893cff
RGS
2324
2325 # must detect sigpipe failures - not catching
2326 # then will cause the debugger to die.
2327 eval {
2328 &main::dumpvar(
2329 $packname,
2330 defined $option{dumpDepth}
e22ea7cc
RF
2331 ? $option{dumpDepth}
2332 : -1, # assume -1 unless specified
69893cff 2333 @vars
e22ea7cc
RF
2334 );
2335 };
2336
2337 # The die doesn't need to include the $@, because
2338 # it will automatically get propagated for us.
2339 if ($@) {
2340 die unless $@ =~ /dumpvar print failed/;
2341 }
2342 } ## end if (defined &main::dumpvar)
2343 else {
2344
2345 # Couldn't load dumpvar.
2346 print $OUT "dumpvar.pl not available.\n";
2347 }
69893cff 2348
69893cff 2349 # Restore the output filehandle, and go round again.
e22ea7cc
RF
2350 select($savout);
2351 next CMD;
2352 };
69893cff
RGS
2353
2354=head4 C<x> - evaluate and print an expression
2355
2356Hands the expression off to C<DB::eval>, setting it up to print the value
2357via C<dumpvar.pl> instead of just printing it directly.
2358
2359=cut
2360
e22ea7cc
RF
2361 $cmd =~ s/^x\b/ / && do { # Remainder gets done by DB::eval()
2362 $onetimeDump = 'dump'; # main::dumpvar shows the output
69893cff
RGS
2363
2364 # handle special "x 3 blah" syntax XXX propagate
2365 # doc back to special variables.
e22ea7cc
RF
2366 if ( $cmd =~ s/^\s*(\d+)(?=\s)/ / ) {
2367 $onetimedumpDepth = $1;
2368 }
2369 };
69893cff
RGS
2370
2371=head4 C<m> - print methods
2372
2373Just uses C<DB::methods> to determine what methods are available.
2374
2375=cut
2376
e22ea7cc
RF
2377 $cmd =~ s/^m\s+([\w:]+)\s*$/ / && do {
2378 methods($1);
2379 next CMD;
2380 };
69893cff
RGS
2381
2382 # m expr - set up DB::eval to do the work
e22ea7cc
RF
2383 $cmd =~ s/^m\b/ / && do { # Rest gets done by DB::eval()
2384 $onetimeDump = 'methods'; # method output gets used there
2385 };
69893cff
RGS
2386
2387=head4 C<f> - switch files
2388
2389=cut
2390
e22ea7cc
RF
2391 $cmd =~ /^f\b\s*(.*)/ && do {
2392 $file = $1;
2393 $file =~ s/\s+$//;
69893cff
RGS
2394
2395 # help for no arguments (old-style was return from sub).
e22ea7cc
RF
2396 if ( !$file ) {
2397 print $OUT
2398 "The old f command is now the r command.\n"; # hint
2399 print $OUT "The new f command switches filenames.\n";
2400 next CMD;
2401 } ## end if (!$file)
69893cff
RGS
2402
2403 # if not in magic file list, try a close match.
e22ea7cc
RF
2404 if ( !defined $main::{ '_<' . $file } ) {
2405 if ( ($try) = grep( m#^_<.*$file#, keys %main:: ) ) {
2406 {
2407 $try = substr( $try, 2 );
1f874cb6 2408 print $OUT "Choosing $try matching '$file':\n";
e22ea7cc
RF
2409 $file = $try;
2410 }
2411 } ## end if (($try) = grep(m#^_<.*$file#...
2412 } ## end if (!defined $main::{ ...
69893cff
RGS
2413
2414 # If not successfully switched now, we failed.
e22ea7cc 2415 if ( !defined $main::{ '_<' . $file } ) {
1f874cb6 2416 print $OUT "No file matching '$file' is loaded.\n";
e22ea7cc
RF
2417 next CMD;
2418 }
69893cff 2419
e22ea7cc
RF
2420 # We switched, so switch the debugger internals around.
2421 elsif ( $file ne $filename ) {
2422 *dbline = $main::{ '_<' . $file };
2423 $max = $#dbline;
2424 $filename = $file;
2425 $start = 1;
2426 $cmd = "l";
2427 } ## end elsif ($file ne $filename)
2428
2429 # We didn't switch; say we didn't.
2430 else {
2431 print $OUT "Already in $file.\n";
2432 next CMD;
2433 }
2434 };
69893cff
RGS
2435
2436=head4 C<.> - return to last-executed line.
2437
2438We set C<$incr> to -1 to indicate that the debugger shouldn't move ahead,
2439and then we look up the line in the magical C<%dbline> hash.
2440
2441=cut
2442
2443 # . command.
e22ea7cc
RF
2444 $cmd =~ /^\.$/ && do {
2445 $incr = -1; # stay at current line
69893cff
RGS
2446
2447 # Reset everything to the old location.
e22ea7cc
RF
2448 $start = $line;
2449 $filename = $filename_ini;
2450 *dbline = $main::{ '_<' . $filename };
2451 $max = $#dbline;
69893cff
RGS
2452
2453 # Now where are we?
e22ea7cc
RF
2454 print_lineinfo($position);
2455 next CMD;
2456 };
69893cff
RGS
2457
2458=head4 C<-> - back one window
2459
2460We change C<$start> to be one window back; if we go back past the first line,
2461we set it to be the first line. We ser C<$incr> to put us back at the
2462currently-executing line, and then put a C<l $start +> (list one window from
2463C<$start>) in C<$cmd> to be executed later.
2464
2465=cut
2466
2467 # - - back a window.
e22ea7cc
RF
2468 $cmd =~ /^-$/ && do {
2469
69893cff 2470 # back up by a window; go to 1 if back too far.
e22ea7cc
RF
2471 $start -= $incr + $window + 1;
2472 $start = 1 if $start <= 0;
2473 $incr = $window - 1;
69893cff
RGS
2474
2475 # Generate and execute a "l +" command (handled below).
e22ea7cc
RF
2476 $cmd = 'l ' . ($start) . '+';
2477 };
69893cff
RGS
2478
2479=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>, {, {{>
2480
2481In Perl 5.8.0, a realignment of the commands was done to fix up a number of
2482problems, most notably that the default case of several commands destroying
2483the user's work in setting watchpoints, actions, etc. We wanted, however, to
2484retain the old commands for those who were used to using them or who preferred
2485them. At this point, we check for the new commands and call C<cmd_wrapper> to
2486deal with them instead of processing them in-line.
2487
2488=cut
2489
2490 # All of these commands were remapped in perl 5.8.0;
e22ea7cc 2491 # we send them off to the secondary dispatcher (see below).
2cbb2ee1 2492 $cmd =~ /^([aAbBeEhilLMoOPvwW]\b|[<>\{]{1,2})\s*(.*)/so && do {
e22ea7cc
RF
2493 &cmd_wrapper( $1, $2, $line );
2494 next CMD;
2495 };
69893cff
RGS
2496
2497=head4 C<y> - List lexicals in higher scope
2498
2499Uses C<PadWalker> to find the lexicals supplied as arguments in a scope
2500above the current one and then displays then using C<dumpvar.pl>.
2501
2502=cut
2503
2504 $cmd =~ /^y(?:\s+(\d*)\s*(.*))?$/ && do {
2505
2506 # See if we've got the necessary support.
2507 eval { require PadWalker; PadWalker->VERSION(0.08) }
2508 or &warn(
2509 $@ =~ /locate/
2510 ? "PadWalker module not found - please install\n"
2511 : $@
2512 )
2513 and next CMD;
2514
2515 # Load up dumpvar if we don't have it. If we can, that is.
e81465be 2516 do 'dumpvar.pl' || die $@ unless defined &main::dumpvar;
69893cff
RGS
2517 defined &main::dumpvar
2518 or print $OUT "dumpvar.pl not available.\n"
2519 and next CMD;
2520
2521 # Got all the modules we need. Find them and print them.
e22ea7cc 2522 my @vars = split( ' ', $2 || '' );
69893cff
RGS
2523
2524 # Find the pad.
e22ea7cc 2525 my $h = eval { PadWalker::peek_my( ( $1 || 0 ) + 1 ) };
69893cff
RGS
2526
2527 # Oops. Can't find it.
2528 $@ and $@ =~ s/ at .*//, &warn($@), next CMD;
2529
2530 # Show the desired vars with dumplex().
2531 my $savout = select($OUT);
2532
2533 # Have dumplex dump the lexicals.
e22ea7cc 2534 dumpvar::dumplex( $_, $h->{$_},
69893cff 2535 defined $option{dumpDepth} ? $option{dumpDepth} : -1,
e22ea7cc
RF
2536 @vars )
2537 for sort keys %$h;
69893cff
RGS
2538 select($savout);
2539 next CMD;
2540 };
2541
2542=head3 COMMANDS NOT WORKING AFTER PROGRAM ENDS
2543
2544All of the commands below this point don't work after the program being
2545debugged has ended. All of them check to see if the program has ended; this
2546allows the commands to be relocated without worrying about a 'line of
2547demarcation' above which commands can be entered anytime, and below which
2548they can't.
2549
2550=head4 C<n> - single step, but don't trace down into subs
2551
2552Done by setting C<$single> to 2, which forces subs to execute straight through
be9a9b1d 2553when entered (see C<DB::sub>). We also save the C<n> command in C<$laststep>,
69893cff
RGS
2554so a null command knows what to re-execute.
2555
2556=cut
2557
e22ea7cc 2558 # n - next
69893cff
RGS
2559 $cmd =~ /^n$/ && do {
2560 end_report(), next CMD if $finished and $level <= 1;
e22ea7cc 2561
69893cff
RGS
2562 # Single step, but don't enter subs.
2563 $single = 2;
e22ea7cc 2564
69893cff 2565 # Save for empty command (repeat last).
e22ea7cc
RF
2566 $laststep = $cmd;
2567 last CMD;
2568 };
69893cff
RGS
2569
2570=head4 C<s> - single-step, entering subs
2571
be9a9b1d 2572Sets C<$single> to 1, which causes C<DB::sub> to continue tracing inside
69893cff
RGS
2573subs. Also saves C<s> as C<$lastcmd>.
2574
2575=cut
2576
2577 # s - single step.
2578 $cmd =~ /^s$/ && do {
e22ea7cc 2579
69893cff
RGS
2580 # Get out and restart the command loop if program
2581 # has finished.
e22ea7cc
RF
2582 end_report(), next CMD if $finished and $level <= 1;
2583
69893cff 2584 # Single step should enter subs.
e22ea7cc
RF
2585 $single = 1;
2586
69893cff 2587 # Save for empty command (repeat last).
e22ea7cc
RF
2588 $laststep = $cmd;
2589 last CMD;
2590 };
69893cff
RGS
2591
2592=head4 C<c> - run continuously, setting an optional breakpoint
2593
2594Most of the code for this command is taken up with locating the optional
2595breakpoint, which is either a subroutine name or a line number. We set
2596the appropriate one-time-break in C<@dbline> and then turn off single-stepping
2597in this and all call levels above this one.
2598
2599=cut
2600
2601 # c - start continuous execution.
2602 $cmd =~ /^c\b\s*([\w:]*)\s*$/ && do {
e22ea7cc 2603
69893cff
RGS
2604 # Hey, show's over. The debugged program finished
2605 # executing already.
2606 end_report(), next CMD if $finished and $level <= 1;
2607
2608 # Capture the place to put a one-time break.
2609 $subname = $i = $1;
2610
e22ea7cc
RF
2611 # Probably not needed, since we finish an interactive
2612 # sub-session anyway...
2613 # local $filename = $filename;
2614 # local *dbline = *dbline; # XXX Would this work?!
69893cff
RGS
2615 #
2616 # The above question wonders if localizing the alias
2617 # to the magic array works or not. Since it's commented
2618 # out, we'll just leave that to speculation for now.
2619
2620 # If the "subname" isn't all digits, we'll assume it
2621 # is a subroutine name, and try to find it.
e22ea7cc
RF
2622 if ( $subname =~ /\D/ ) { # subroutine name
2623 # Qualify it to the current package unless it's
2624 # already qualified.
69893cff
RGS
2625 $subname = $package . "::" . $subname
2626 unless $subname =~ /::/;
e22ea7cc 2627
69893cff
RGS
2628 # find_sub will return "file:line_number" corresponding
2629 # to where the subroutine is defined; we call find_sub,
e22ea7cc 2630 # break up the return value, and assign it in one
69893cff 2631 # operation.
e22ea7cc 2632 ( $file, $i ) = ( find_sub($subname) =~ /^(.*):(.*)$/ );
69893cff
RGS
2633
2634 # Force the line number to be numeric.
e22ea7cc 2635 $i += 0;
69893cff
RGS
2636
2637 # If we got a line number, we found the sub.
e22ea7cc
RF
2638 if ($i) {
2639
69893cff
RGS
2640 # Switch all the debugger's internals around so
2641 # we're actually working with that file.
e22ea7cc
RF
2642 $filename = $file;
2643 *dbline = $main::{ '_<' . $filename };
2644
69893cff 2645 # Mark that there's a breakpoint in this file.
e22ea7cc
RF
2646 $had_breakpoints{$filename} |= 1;
2647
69893cff
RGS
2648 # Scan forward to the first executable line
2649 # after the 'sub whatever' line.
e22ea7cc
RF
2650 $max = $#dbline;
2651 ++$i while $dbline[$i] == 0 && $i < $max;
2652 } ## end if ($i)
69893cff
RGS
2653
2654 # We didn't find a sub by that name.
e22ea7cc
RF
2655 else {
2656 print $OUT "Subroutine $subname not found.\n";
2657 next CMD;
2658 }
2659 } ## end if ($subname =~ /\D/)
69893cff
RGS
2660
2661 # At this point, either the subname was all digits (an
2662 # absolute line-break request) or we've scanned through
2663 # the code following the definition of the sub, looking
2664 # for an executable, which we may or may not have found.
2665 #
2666 # If $i (which we set $subname from) is non-zero, we
e22ea7cc
RF
2667 # got a request to break at some line somewhere. On
2668 # one hand, if there wasn't any real subroutine name
2669 # involved, this will be a request to break in the current
2670 # file at the specified line, so we have to check to make
69893cff
RGS
2671 # sure that the line specified really is breakable.
2672 #
2673 # On the other hand, if there was a subname supplied, the
3c4b39be 2674 # preceding block has moved us to the proper file and
69893cff
RGS
2675 # location within that file, and then scanned forward
2676 # looking for the next executable line. We have to make
2677 # sure that one was found.
2678 #
2679 # On the gripping hand, we can't do anything unless the
2680 # current value of $i points to a valid breakable line.
2681 # Check that.
e22ea7cc
RF
2682 if ($i) {
2683
69893cff 2684 # Breakable?
e22ea7cc
RF
2685 if ( $dbline[$i] == 0 ) {
2686 print $OUT "Line $i not breakable.\n";
2687 next CMD;
2688 }
2689
69893cff 2690 # Yes. Set up the one-time-break sigil.
e22ea7cc 2691 $dbline{$i} =~ s/($|\0)/;9$1/; # add one-time-only b.p.
5d5d9ea3 2692 _enable_breakpoint_temp_enabled_status($filename, $i);
e22ea7cc 2693 } ## end if ($i)
69893cff
RGS
2694
2695 # Turn off stack tracing from here up.
2c247e84
SF
2696 for my $i (0 .. $stack_depth) {
2697 $stack[ $i ] &= ~1;
e22ea7cc
RF
2698 }
2699 last CMD;
2700 };
69893cff
RGS
2701
2702=head4 C<r> - return from a subroutine
2703
2704For C<r> to work properly, the debugger has to stop execution again
2705immediately after the return is executed. This is done by forcing
2706single-stepping to be on in the call level above the current one. If
2707we are printing return values when a C<r> is executed, set C<$doret>
2708appropriately, and force us out of the command loop.
2709
2710=cut
2711
2712 # r - return from the current subroutine.
e22ea7cc
RF
2713 $cmd =~ /^r$/ && do {
2714
98dc9551 2715 # Can't do anything if the program's over.
e22ea7cc
RF
2716 end_report(), next CMD if $finished and $level <= 1;
2717
69893cff 2718 # Turn on stack trace.
e22ea7cc
RF
2719 $stack[$stack_depth] |= 1;
2720
69893cff 2721 # Print return value unless the stack is empty.
e22ea7cc
RF
2722 $doret = $option{PrintRet} ? $stack_depth - 1 : -2;
2723 last CMD;
2724 };
69893cff 2725
69893cff
RGS
2726=head4 C<T> - stack trace
2727
2728Just calls C<DB::print_trace>.
2729
2730=cut
2731
e22ea7cc
RF
2732 $cmd =~ /^T$/ && do {
2733 print_trace( $OUT, 1 ); # skip DB
2734 next CMD;
2735 };
69893cff
RGS
2736
2737=head4 C<w> - List window around current line.
2738
2739Just calls C<DB::cmd_w>.
2740
2741=cut
2742
e22ea7cc 2743 $cmd =~ /^w\b\s*(.*)/s && do { &cmd_w( 'w', $1 ); next CMD; };
69893cff
RGS
2744
2745=head4 C<W> - watch-expression processing.
2746
2747Just calls C<DB::cmd_W>.
2748
2749=cut
2750
e22ea7cc 2751 $cmd =~ /^W\b\s*(.*)/s && do { &cmd_W( 'W', $1 ); next CMD; };
69893cff
RGS
2752
2753=head4 C</> - search forward for a string in the source
2754
2755We take the argument and treat it as a pattern. If it turns out to be a
2756bad one, we return the error we got from trying to C<eval> it and exit.
2757If not, we create some code to do the search and C<eval> it so it can't
2758mess us up.
2759
2760=cut
2761
e22ea7cc 2762 $cmd =~ /^\/(.*)$/ && do {
69893cff
RGS
2763
2764 # The pattern as a string.
2c247e84
SF
2765 use vars qw($inpat);
2766 $inpat = $1;
69893cff
RGS
2767
2768 # Remove the final slash.
e22ea7cc 2769 $inpat =~ s:([^\\])/$:$1:;
69893cff
RGS
2770
2771 # If the pattern isn't null ...
e22ea7cc 2772 if ( $inpat ne "" ) {
69893cff
RGS
2773
2774 # Turn of warn and die procesing for a bit.
e22ea7cc
RF
2775 local $SIG{__DIE__};
2776 local $SIG{__WARN__};
69893cff
RGS
2777
2778 # Create the pattern.
e22ea7cc
RF
2779 eval '$inpat =~ m' . "\a$inpat\a";
2780 if ( $@ ne "" ) {
2781
69893cff 2782 # Oops. Bad pattern. No biscuit.
e22ea7cc 2783 # Print the eval error and go back for more
69893cff 2784 # commands.
e22ea7cc
RF
2785 print $OUT "$@";
2786 next CMD;
2787 }
2788 $pat = $inpat;
2789 } ## end if ($inpat ne "")
69893cff
RGS
2790
2791 # Set up to stop on wrap-around.
e22ea7cc 2792 $end = $start;
69893cff
RGS
2793
2794 # Don't move off the current line.
e22ea7cc 2795 $incr = -1;
69893cff
RGS
2796
2797 # Done in eval so nothing breaks if the pattern
2798 # does something weird.
e22ea7cc
RF
2799 eval '
2800 for (;;) {
69893cff 2801 # Move ahead one line.
e22ea7cc 2802 ++$start;
69893cff
RGS
2803
2804 # Wrap if we pass the last line.
e22ea7cc 2805 $start = 1 if ($start > $max);
69893cff
RGS
2806
2807 # Stop if we have gotten back to this line again,
e22ea7cc 2808 last if ($start == $end);
69893cff
RGS
2809
2810 # A hit! (Note, though, that we are doing
2811 # case-insensitive matching. Maybe a qr//
2812 # expression would be better, so the user could
2813 # do case-sensitive matching if desired.
e22ea7cc
RF
2814 if ($dbline[$start] =~ m' . "\a$pat\a" . 'i) {
2815 if ($slave_editor) {
69893cff 2816 # Handle proper escaping in the slave.
e22ea7cc
RF
2817 print $OUT "\032\032$filename:$start:0\n";
2818 }
2819 else {
69893cff 2820 # Just print the line normally.
e22ea7cc
RF
2821 print $OUT "$start:\t",$dbline[$start],"\n";
2822 }
69893cff 2823 # And quit since we found something.
e22ea7cc
RF
2824 last;
2825 }
2826 } ';
2827
69893cff 2828 # If we wrapped, there never was a match.
e22ea7cc
RF
2829 print $OUT "/$pat/: not found\n" if ( $start == $end );
2830 next CMD;
2831 };
69893cff
RGS
2832
2833=head4 C<?> - search backward for a string in the source
2834
2835Same as for C</>, except the loop runs backwards.
2836
2837=cut
2838
2839 # ? - backward pattern search.
e22ea7cc 2840 $cmd =~ /^\?(.*)$/ && do {
69893cff
RGS
2841
2842 # Get the pattern, remove trailing question mark.
6b24a4b7 2843 my $inpat = $1;
e22ea7cc 2844 $inpat =~ s:([^\\])\?$:$1:;
69893cff
RGS
2845
2846 # If we've got one ...
e22ea7cc 2847 if ( $inpat ne "" ) {
69893cff
RGS
2848
2849 # Turn off die & warn handlers.
e22ea7cc
RF
2850 local $SIG{__DIE__};
2851 local $SIG{__WARN__};
2852 eval '$inpat =~ m' . "\a$inpat\a";
2853
2854 if ( $@ ne "" ) {
2855
69893cff 2856 # Ouch. Not good. Print the error.
e22ea7cc
RF
2857 print $OUT $@;
2858 next CMD;
2859 }
2860 $pat = $inpat;
69893cff 2861 } ## end if ($inpat ne "")
e22ea7cc 2862
69893cff 2863 # Where we are now is where to stop after wraparound.
e22ea7cc 2864 $end = $start;
69893cff
RGS
2865
2866 # Don't move away from this line.
e22ea7cc 2867 $incr = -1;
69893cff
RGS
2868
2869 # Search inside the eval to prevent pattern badness
2870 # from killing us.
e22ea7cc
RF
2871 eval '
2872 for (;;) {
69893cff 2873 # Back up a line.
e22ea7cc 2874 --$start;
69893cff
RGS
2875
2876 # Wrap if we pass the first line.
e22ea7cc
RF
2877
2878 $start = $max if ($start <= 0);
69893cff
RGS
2879
2880 # Quit if we get back where we started,
e22ea7cc 2881 last if ($start == $end);
69893cff
RGS
2882
2883 # Match?
e22ea7cc
RF
2884 if ($dbline[$start] =~ m' . "\a$pat\a" . 'i) {
2885 if ($slave_editor) {
69893cff 2886 # Yep, follow slave editor requirements.
e22ea7cc
RF
2887 print $OUT "\032\032$filename:$start:0\n";
2888 }
2889 else {
69893cff 2890 # Yep, just print normally.
e22ea7cc
RF
2891 print $OUT "$start:\t",$dbline[$start],"\n";
2892 }
69893cff
RGS
2893
2894 # Found, so done.
e22ea7cc
RF
2895 last;
2896 }
2897 } ';
2898
2899 # Say we failed if the loop never found anything,
2900 print $OUT "?$pat?: not found\n" if ( $start == $end );
2901 next CMD;
2902 };
69893cff
RGS
2903
2904=head4 C<$rc> - Recall command
2905
2906Manages the commands in C<@hist> (which is created if C<Term::ReadLine> reports
2907that the terminal supports history). It find the the command required, puts it
2908into C<$cmd>, and redoes the loop to execute it.
2909
2910=cut
2911
e22ea7cc
RF
2912 # $rc - recall command.
2913 $cmd =~ /^$rc+\s*(-)?(\d+)?$/ && do {
69893cff
RGS
2914
2915 # No arguments, take one thing off history.
e22ea7cc 2916 pop(@hist) if length($cmd) > 1;
69893cff 2917
e22ea7cc 2918 # Relative (- found)?
69893cff 2919 # Y - index back from most recent (by 1 if bare minus)
e22ea7cc 2920 # N - go to that particular command slot or the last
69893cff 2921 # thing if nothing following.
e22ea7cc 2922 $i = $1 ? ( $#hist - ( $2 || 1 ) ) : ( $2 || $#hist );
69893cff
RGS
2923
2924 # Pick out the command desired.
e22ea7cc 2925 $cmd = $hist[$i];
69893cff
RGS
2926
2927 # Print the command to be executed and restart the loop
2928 # with that command in the buffer.
e22ea7cc
RF
2929 print $OUT $cmd, "\n";
2930 redo CMD;
2931 };
69893cff
RGS
2932
2933=head4 C<$sh$sh> - C<system()> command
2934
2935Calls the C<DB::system()> to handle the command. This keeps the C<STDIN> and
2936C<STDOUT> from getting messed up.
2937
2938=cut
2939
2940 # $sh$sh - run a shell command (if it's all ASCII).
2941 # Can't run shell commands with Unicode in the debugger, hmm.
e22ea7cc
RF
2942 $cmd =~ /^$sh$sh\s*([\x00-\xff]*)/ && do {
2943
69893cff 2944 # System it.
e22ea7cc
RF
2945 &system($1);
2946 next CMD;
2947 };
69893cff
RGS
2948
2949=head4 C<$rc I<pattern> $rc> - Search command history
2950
2951Another command to manipulate C<@hist>: this one searches it with a pattern.
be9a9b1d 2952If a command is found, it is placed in C<$cmd> and executed via C<redo>.
69893cff
RGS
2953
2954=cut
2955
e22ea7cc
RF
2956 # $rc pattern $rc - find a command in the history.
2957 $cmd =~ /^$rc([^$rc].*)$/ && do {
2958
69893cff 2959 # Create the pattern to use.
e22ea7cc 2960 $pat = "^$1";
69893cff
RGS
2961
2962 # Toss off last entry if length is >1 (and it always is).
e22ea7cc 2963 pop(@hist) if length($cmd) > 1;
69893cff
RGS
2964
2965 # Look backward through the history.
72d7d80d 2966 for ( $i = $#hist ; $i ; --$i ) {
69893cff 2967 # Stop if we find it.
e22ea7cc
RF
2968 last if $hist[$i] =~ /$pat/;
2969 }
2970
2971 if ( !$i ) {
69893cff 2972
69893cff 2973 # Never found it.
e22ea7cc
RF
2974 print $OUT "No such command!\n\n";
2975 next CMD;
2976 }
69893cff
RGS
2977
2978 # Found it. Put it in the buffer, print it, and process it.
e22ea7cc
RF
2979 $cmd = $hist[$i];
2980 print $OUT $cmd, "\n";
2981 redo CMD;
2982 };
69893cff
RGS
2983
2984=head4 C<$sh> - Invoke a shell
2985
2986Uses C<DB::system> to invoke a shell.
2987
2988=cut
2989
2990 # $sh - start a shell.
e22ea7cc
RF
2991 $cmd =~ /^$sh$/ && do {
2992
69893cff
RGS
2993 # Run the user's shell. If none defined, run Bourne.
2994 # We resume execution when the shell terminates.
e22ea7cc
RF
2995 &system( $ENV{SHELL} || "/bin/sh" );
2996 next CMD;
2997 };
69893cff
RGS
2998
2999=head4 C<$sh I<command>> - Force execution of a command in a shell
3000
3001Like the above, but the command is passed to the shell. Again, we use
3002C<DB::system> to avoid problems with C<STDIN> and C<STDOUT>.
3003
3004=cut
3005
3006 # $sh command - start a shell and run a command in it.
e22ea7cc
RF
3007 $cmd =~ /^$sh\s*([\x00-\xff]*)/ && do {
3008
3009 # XXX: using csh or tcsh destroys sigint retvals!
3010 #&system($1); # use this instead
69893cff
RGS
3011
3012 # use the user's shell, or Bourne if none defined.
e22ea7cc
RF
3013 &system( $ENV{SHELL} || "/bin/sh", "-c", $1 );
3014 next CMD;
3015 };
69893cff
RGS
3016
3017=head4 C<H> - display commands in history
3018
3019Prints the contents of C<@hist> (if any).
3020
3021=cut
3022
7fddc82f
RF
3023 $cmd =~ /^H\b\s*\*/ && do {
3024 @hist = @truehist = ();
3025 print $OUT "History cleansed\n";
3026 next CMD;
3027 };
e22ea7cc
RF
3028
3029 $cmd =~ /^H\b\s*(-(\d+))?/ && do {
3030
3031 # Anything other than negative numbers is ignored by
69893cff 3032 # the (incorrect) pattern, so this test does nothing.
e22ea7cc 3033 $end = $2 ? ( $#hist - $2 ) : 0;
69893cff
RGS
3034
3035 # Set to the minimum if less than zero.
e22ea7cc 3036 $hist = 0 if $hist < 0;
69893cff 3037
e22ea7cc 3038 # Start at the end of the array.
69893cff
RGS
3039 # Stay in while we're still above the ending value.
3040 # Tick back by one each time around the loop.
72d7d80d 3041 for ( $i = $#hist ; $i > $end ; $i-- ) {
69893cff
RGS
3042
3043 # Print the command unless it has no arguments.
e22ea7cc
RF
3044 print $OUT "$i: ", $hist[$i], "\n"
3045 unless $hist[$i] =~ /^.?$/;
3046 }
3047 next CMD;
3048 };
69893cff
RGS
3049
3050=head4 C<man, doc, perldoc> - look up documentation
3051
3052Just calls C<runman()> to print the appropriate document.
3053
3054=cut
3055
e22ea7cc
RF
3056 # man, perldoc, doc - show manual pages.
3057 $cmd =~ /^(?:man|(?:perl)?doc)\b(?:\s+([^(]*))?$/ && do {
3058 runman($1);
3059 next CMD;
3060 };
69893cff
RGS
3061
3062=head4 C<p> - print
3063
3064Builds a C<print EXPR> expression in the C<$cmd>; this will get executed at
3065the bottom of the loop.
3066
3067=cut
3068
3069 # p - print (no args): print $_.
e22ea7cc 3070 $cmd =~ s/^p$/print {\$DB::OUT} \$_/;
69893cff
RGS
3071
3072 # p - print the given expression.
e22ea7cc 3073 $cmd =~ s/^p\b/print {\$DB::OUT} /;
69893cff
RGS
3074
3075=head4 C<=> - define command alias
3076
3077Manipulates C<%alias> to add or list command aliases.
3078
3079=cut
3080
e22ea7cc
RF
3081 # = - set up a command alias.
3082 $cmd =~ s/^=\s*// && do {
3083 my @keys;
3084 if ( length $cmd == 0 ) {
3085
69893cff 3086 # No args, get current aliases.
e22ea7cc
RF
3087 @keys = sort keys %alias;
3088 }
3089 elsif ( my ( $k, $v ) = ( $cmd =~ /^(\S+)\s+(\S.*)/ ) ) {
3090
69893cff
RGS
3091 # Creating a new alias. $k is alias name, $v is
3092 # alias value.
3093
e22ea7cc
RF
3094 # can't use $_ or kill //g state
3095 for my $x ( $k, $v ) {
3096
3097 # Escape "alarm" characters.
3098 $x =~ s/\a/\\a/g;
3099 }
69893cff
RGS
3100
3101 # Substitute key for value, using alarm chars
e22ea7cc 3102 # as separators (which is why we escaped them in
69893cff 3103 # the command).
e22ea7cc 3104 $alias{$k} = "s\a$k\a$v\a";
69893cff
RGS
3105
3106 # Turn off standard warn and die behavior.
e22ea7cc
RF
3107 local $SIG{__DIE__};
3108 local $SIG{__WARN__};
69893cff
RGS
3109
3110 # Is it valid Perl?
e22ea7cc
RF
3111 unless ( eval "sub { s\a$k\a$v\a }; 1" ) {
3112
69893cff 3113 # Nope. Bad alias. Say so and get out.
e22ea7cc
RF
3114 print $OUT "Can't alias $k to $v: $@\n";
3115 delete $alias{$k};
3116 next CMD;
3117 }
3118
69893cff 3119 # We'll only list the new one.
e22ea7cc 3120 @keys = ($k);
69893cff
RGS
3121 } ## end elsif (my ($k, $v) = ($cmd...
3122
3123 # The argument is the alias to list.
e22ea7cc
RF
3124 else {
3125 @keys = ($cmd);
3126 }
69893cff
RGS
3127
3128 # List aliases.
e22ea7cc
RF
3129 for my $k (@keys) {
3130
98dc9551 3131 # Messy metaquoting: Trim the substitution code off.
69893cff
RGS
3132 # We use control-G as the delimiter because it's not
3133 # likely to appear in the alias.
e22ea7cc
RF
3134 if ( ( my $v = $alias{$k} ) =~ s\as\a$k\a(.*)\a$\a1\a ) {
3135
69893cff 3136 # Print the alias.
e22ea7cc
RF
3137 print $OUT "$k\t= $1\n";
3138 }
3139 elsif ( defined $alias{$k} ) {
3140
69893cff 3141 # Couldn't trim it off; just print the alias code.
e22ea7cc
RF
3142 print $OUT "$k\t$alias{$k}\n";
3143 }
3144 else {
3145
69893cff 3146 # No such, dude.
e22ea7cc
RF
3147 print "No alias for $k\n";
3148 }
69893cff 3149 } ## end for my $k (@keys)
e22ea7cc
RF
3150 next CMD;
3151 };
69893cff
RGS
3152
3153=head4 C<source> - read commands from a file.
3154
3155Opens a lexical filehandle and stacks it on C<@cmdfhs>; C<DB::readline> will
3156pick it up.
3157
3158=cut
3159
e22ea7cc
RF
3160 # source - read commands from a file (or pipe!) and execute.
3161 $cmd =~ /^source\s+(.*\S)/ && do {
3162 if ( open my $fh, $1 ) {
3163
69893cff 3164 # Opened OK; stick it in the list of file handles.
e22ea7cc
RF
3165 push @cmdfhs, $fh;
3166 }
3167 else {
3168
3169 # Couldn't open it.
1f874cb6 3170 &warn("Can't execute '$1': $!\n");
e22ea7cc
RF
3171 }
3172 next CMD;
3173 };
69893cff 3174
e09195af
SF
3175 $cmd =~ /^(enable|disable)\s+(\S+)\s*$/ && do {
3176 my ($cmd, $position) = ($1, $2);
3177
3178 my ($fn, $line_num);
3179 if ($position =~ m{\A\d+\z})
3180 {
3181 $fn = $filename;
3182 $line_num = $position;
3183 }
3184 elsif ($position =~ m{\A(.*):(\d+)\z})
3185 {
3186 ($fn, $line_num) = ($1, $2);
3187 }
3188 else
3189 {
3190 &warn("Wrong spec for enable/disable argument.\n");
3191 }
3192
3193 if (defined($fn)) {
3194 if (_has_breakpoint_data_ref($fn, $line_num)) {
3195 _set_breakpoint_enabled_status($fn, $line_num,
3196 ($cmd eq 'enable' ? 1 : '')
3197 );
3198 }
3199 else {
3200 &warn("No breakpoint set at ${fn}:${line_num}\n");
3201 }
3202 }
3203
3204 next CMD;
3205 };
3206
69893cff
RGS
3207=head4 C<save> - send current history to a file
3208
3209Takes the complete history, (not the shrunken version you see with C<H>),
3210and saves it to the given filename, so it can be replayed using C<source>.
3211
3212Note that all C<^(save|source)>'s are commented out with a view to minimise recursion.
3213
3214=cut
3215
3216 # save source - write commands to a file for later use
3217 $cmd =~ /^save\s*(.*)$/ && do {
e22ea7cc
RF
3218 my $file = $1 || '.perl5dbrc'; # default?
3219 if ( open my $fh, "> $file" ) {
3220
3221 # chomp to remove extraneous newlines from source'd files
3222 chomp( my @truelist =
3223 map { m/^\s*(save|source)/ ? "#$_" : $_ }
3224 @truehist );
3225 print $fh join( "\n", @truelist );
69893cff 3226 print "commands saved in $file\n";
e22ea7cc
RF
3227 }
3228 else {
69893cff
RGS
3229 &warn("Can't save debugger commands in '$1': $!\n");
3230 }
3231 next CMD;
3232 };
3233
7fddc82f
RF
3234=head4 C<R> - restart
3235
3236Restart the debugger session.
3237
3238=head4 C<rerun> - rerun the current session
3239
3240Return to any given position in the B<true>-history list
3241
3242=cut
3243
3244 # R - restart execution.
3245 # rerun - controlled restart execution.
3246 $cmd =~ /^(R|rerun\s*(.*))$/ && do {
3247 my @args = ($1 eq 'R' ? restart() : rerun($2));
3248
ca28b541
AP
3249 # Close all non-system fds for a clean restart. A more
3250 # correct method would be to close all fds that were not
3251 # open when the process started, but this seems to be
3252 # hard. See "debugger 'R'estart and open database
3253 # connections" on p5p.
3254
47d3bbda 3255 my $max_fd = 1024; # default if POSIX can't be loaded
ca28b541 3256 if (eval { require POSIX }) {
5332cc68 3257 eval { $max_fd = POSIX::sysconf(POSIX::_SC_OPEN_MAX()) };
ca28b541
AP
3258 }
3259
3260 if (defined $max_fd) {
3261 foreach ($^F+1 .. $max_fd-1) {
3262 next unless open FD_TO_CLOSE, "<&=$_";
3263 close(FD_TO_CLOSE);
3264 }
3265 }
3266
7fddc82f
RF
3267 # And run Perl again. We use exec() to keep the
3268 # PID stable (and that way $ini_pids is still valid).
3269 exec(@args) || print $OUT "exec failed: $!\n";
3270
3271 last CMD;
3272 };
3273
69893cff
RGS
3274=head4 C<|, ||> - pipe output through the pager.
3275
be9a9b1d 3276For C<|>, we save C<OUT> (the debugger's output filehandle) and C<STDOUT>
69893cff
RGS
3277(the program's standard output). For C<||>, we only save C<OUT>. We open a
3278pipe to the pager (restoring the output filehandles if this fails). If this
3279is the C<|> command, we also set up a C<SIGPIPE> handler which will simply
3280set C<$signal>, sending us back into the debugger.
3281
3282We then trim off the pipe symbols and C<redo> the command loop at the
3283C<PIPE> label, causing us to evaluate the command in C<$cmd> without
3284reading another.
3285
3286=cut
3287
3288 # || - run command in the pager, with output to DB::OUT.
e22ea7cc
RF
3289 $cmd =~ /^\|\|?\s*[^|]/ && do {
3290 if ( $pager =~ /^\|/ ) {
3291
69893cff 3292 # Default pager is into a pipe. Redirect I/O.
e22ea7cc
RF
3293 open( SAVEOUT, ">&STDOUT" )
3294 || &warn("Can't save STDOUT");
3295 open( STDOUT, ">&OUT" )
3296 || &warn("Can't redirect STDOUT");
69893cff 3297 } ## end if ($pager =~ /^\|/)
e22ea7cc
RF
3298 else {
3299
69893cff 3300 # Not into a pipe. STDOUT is safe.
e22ea7cc
RF
3301 open( SAVEOUT, ">&OUT" ) || &warn("Can't save DB::OUT");
3302 }
69893cff
RGS
3303
3304 # Fix up environment to record we have less if so.
e22ea7cc
RF
3305 fix_less();
3306
3307 unless ( $piped = open( OUT, $pager ) ) {
69893cff 3308
69893cff 3309 # Couldn't open pipe to pager.
1f874cb6 3310 &warn("Can't pipe output to '$pager'");
e22ea7cc
RF
3311 if ( $pager =~ /^\|/ ) {
3312
69893cff 3313 # Redirect I/O back again.
e22ea7cc
RF
3314 open( OUT, ">&STDOUT" ) # XXX: lost message
3315 || &warn("Can't restore DB::OUT");
3316 open( STDOUT, ">&SAVEOUT" )
3317 || &warn("Can't restore STDOUT");
3318 close(SAVEOUT);
69893cff 3319 } ## end if ($pager =~ /^\|/)
e22ea7cc
RF
3320 else {
3321
69893cff 3322 # Redirect I/O. STDOUT already safe.
e22ea7cc
RF
3323 open( OUT, ">&STDOUT" ) # XXX: lost message
3324 || &warn("Can't restore DB::OUT");
3325 }
3326 next CMD;
69893cff
RGS
3327 } ## end unless ($piped = open(OUT,...
3328
3329 # Set up broken-pipe handler if necessary.
e22ea7cc
RF
3330 $SIG{PIPE} = \&DB::catch
3331 if $pager =~ /^\|/
3332 && ( "" eq $SIG{PIPE} || "DEFAULT" eq $SIG{PIPE} );
69893cff
RGS
3333
3334 # Save current filehandle, unbuffer out, and put it back.
e22ea7cc
RF
3335 $selected = select(OUT);
3336 $| = 1;
69893cff
RGS
3337
3338 # Don't put it back if pager was a pipe.
e22ea7cc 3339 select($selected), $selected = "" unless $cmd =~ /^\|\|/;
69893cff
RGS
3340
3341 # Trim off the pipe symbols and run the command now.
e22ea7cc
RF
3342 $cmd =~ s/^\|+\s*//;
3343 redo PIPE;
3344 };
69893cff
RGS
3345
3346=head3 END OF COMMAND PARSING
3347
3348Anything left in C<$cmd> at this point is a Perl expression that we want to
3349evaluate. We'll always evaluate in the user's context, and fully qualify
3350any variables we might want to address in the C<DB> package.
3351
3352=cut
3353
3354 # t - turn trace on.
611272bb
PS
3355 $cmd =~ s/^t\s+(\d+)?/\$DB::trace |= 1;\n/ && do {
3356 $trace_to_depth = $1 ? $stack_depth||0 + $1 : 1E9;
3357 };
69893cff
RGS
3358
3359 # s - single-step. Remember the last command was 's'.
e22ea7cc 3360 $cmd =~ s/^s\s/\$DB::single = 1;\n/ && do { $laststep = 's' };
69893cff
RGS
3361
3362 # n - single-step, but not into subs. Remember last command
e22ea7cc
RF
3363 # was 'n'.
3364 $cmd =~ s/^n\s/\$DB::single = 2;\n/ && do { $laststep = 'n' };
69893cff 3365
e22ea7cc 3366 } # PIPE:
69893cff 3367
e22ea7cc 3368 # Make sure the flag that says "the debugger's running" is
69893cff 3369 # still on, to make sure we get control again.
e22ea7cc 3370 $evalarg = "\$^D = \$^D | \$DB::db_stop;\n$cmd";
69893cff
RGS
3371
3372 # Run *our* eval that executes in the caller's context.
e22ea7cc 3373 &eval;
69893cff
RGS
3374
3375 # Turn off the one-time-dump stuff now.
e22ea7cc
RF
3376 if ($onetimeDump) {
3377 $onetimeDump = undef;
69893cff 3378 $onetimedumpDepth = undef;
e22ea7cc
RF
3379 }
3380 elsif ( $term_pid == $$ ) {
c7e68384
IZ
3381 eval { # May run under miniperl, when not available...
3382 STDOUT->flush();
3383 STDERR->flush();
3384 };
e22ea7cc 3385
69893cff 3386 # XXX If this is the master pid, print a newline.
e22ea7cc
RF
3387 print $OUT "\n";
3388 }
3389 } ## end while (($term || &setterm...
69893cff
RGS
3390
3391=head3 POST-COMMAND PROCESSING
3392
3393After each command, we check to see if the command output was piped anywhere.
3394If so, we go through the necessary code to unhook the pipe and go back to
3395our standard filehandles for input and output.
3396
3397=cut
3398
e22ea7cc 3399 continue { # CMD:
69893cff
RGS
3400
3401 # At the end of every command:
e22ea7cc
RF
3402 if ($piped) {
3403
69893cff 3404 # Unhook the pipe mechanism now.
e22ea7cc
RF
3405 if ( $pager =~ /^\|/ ) {
3406
69893cff 3407 # No error from the child.
e22ea7cc 3408 $? = 0;
69893cff 3409
e22ea7cc
RF
3410 # we cannot warn here: the handle is missing --tchrist
3411 close(OUT) || print SAVEOUT "\nCan't close DB::OUT\n";
69893cff 3412
e22ea7cc 3413 # most of the $? crud was coping with broken cshisms
69893cff 3414 # $? is explicitly set to 0, so this never runs.
e22ea7cc 3415 if ($?) {
1f874cb6 3416 print SAVEOUT "Pager '$pager' failed: ";
e22ea7cc
RF
3417 if ( $? == -1 ) {
3418 print SAVEOUT "shell returned -1\n";
3419 }
3420 elsif ( $? >> 8 ) {
3421 print SAVEOUT ( $? & 127 )
3422 ? " (SIG#" . ( $? & 127 ) . ")"
3423 : "", ( $? & 128 ) ? " -- core dumped" : "", "\n";
3424 }
3425 else {
3426 print SAVEOUT "status ", ( $? >> 8 ), "\n";
3427 }
69893cff
RGS
3428 } ## end if ($?)
3429
e22ea7cc 3430 # Reopen filehandle for our output (if we can) and
69893cff 3431 # restore STDOUT (if we can).
e22ea7cc
RF
3432 open( OUT, ">&STDOUT" ) || &warn("Can't restore DB::OUT");
3433 open( STDOUT, ">&SAVEOUT" )
3434 || &warn("Can't restore STDOUT");
69893cff
RGS
3435
3436 # Turn off pipe exception handler if necessary.
e22ea7cc 3437 $SIG{PIPE} = "DEFAULT" if $SIG{PIPE} eq \&DB::catch;
69893cff 3438
e22ea7cc
RF
3439 # Will stop ignoring SIGPIPE if done like nohup(1)
3440 # does SIGINT but Perl doesn't give us a choice.
69893cff 3441 } ## end if ($pager =~ /^\|/)
e22ea7cc
RF
3442 else {
3443
69893cff 3444 # Non-piped "pager". Just restore STDOUT.
e22ea7cc
RF
3445 open( OUT, ">&SAVEOUT" ) || &warn("Can't restore DB::OUT");
3446 }
69893cff
RGS
3447
3448 # Close filehandle pager was using, restore the normal one
3449 # if necessary,
3450 close(SAVEOUT);
e22ea7cc 3451 select($selected), $selected = "" unless $selected eq "";
69893cff
RGS
3452
3453 # No pipes now.
e22ea7cc 3454 $piped = "";
69893cff 3455 } ## end if ($piped)
e22ea7cc 3456 } # CMD:
69893cff
RGS
3457
3458=head3 COMMAND LOOP TERMINATION
3459
3460When commands have finished executing, we come here. If the user closed the
3461input filehandle, we turn on C<$fall_off_end> to emulate a C<q> command. We
3462evaluate any post-prompt items. We restore C<$@>, C<$!>, C<$^E>, C<$,>, C<$/>,
3463C<$\>, and C<$^W>, and return a null list as expected by the Perl interpreter.
3464The interpreter will then execute the next line and then return control to us
3465again.
3466
3467=cut
3468
3469 # No more commands? Quit.
1f874cb6 3470 $fall_off_end = 1 unless defined $cmd; # Emulate 'q' on EOF
69893cff
RGS
3471
3472 # Evaluate post-prompt commands.
e22ea7cc
RF
3473 foreach $evalarg (@$post) {
3474 &eval;
3475 }
3476 } # if ($single || $signal)
69893cff
RGS
3477
3478 # Put the user's globals back where you found them.
e22ea7cc 3479 ( $@, $!, $^E, $,, $/, $\, $^W ) = @saved;
69893cff
RGS
3480 ();
3481} ## end sub DB
3482
3483# The following code may be executed now:
3484# BEGIN {warn 4}
3485
3486=head2 sub
3487
3488C<sub> is called whenever a subroutine call happens in the program being
3489debugged. The variable C<$DB::sub> contains the name of the subroutine
3490being called.
3491
3492The core function of this subroutine is to actually call the sub in the proper
3493context, capturing its output. This of course causes C<DB::DB> to get called
3494again, repeating until the subroutine ends and returns control to C<DB::sub>
3495again. Once control returns, C<DB::sub> figures out whether or not to dump the
3496return value, and returns its captured copy of the return value as its own
3497return value. The value then feeds back into the program being debugged as if
3498C<DB::sub> hadn't been there at all.
3499
3500C<sub> does all the work of printing the subroutine entry and exit messages
3501enabled by setting C<$frame>. It notes what sub the autoloader got called for,
3502and also prints the return value if needed (for the C<r> command and if
3503the 16 bit is set in C<$frame>).
3504
3505It also tracks the subroutine call depth by saving the current setting of
3506C<$single> in the C<@stack> package global; if this exceeds the value in
3507C<$deep>, C<sub> automatically turns on printing of the current depth by
be9a9b1d 3508setting the C<4> bit in C<$single>. In any case, it keeps the current setting
69893cff
RGS
3509of stop/don't stop on entry to subs set as it currently is set.
3510
3511=head3 C<caller()> support
3512
3513If C<caller()> is called from the package C<DB>, it provides some
3514additional data, in the following order:
3515
3516=over 4
3517
3518=item * C<$package>
3519
3520The package name the sub was in
3521
3522=item * C<$filename>
3523
3524The filename it was defined in
3525
3526=item * C<$line>
3527
3528The line number it was defined on
3529
3530=item * C<$subroutine>
3531
be9a9b1d 3532The subroutine name; C<(eval)> if an C<eval>().
69893cff
RGS
3533
3534=item * C<$hasargs>
3535
35361 if it has arguments, 0 if not
3537
3538=item * C<$wantarray>
3539
35401 if array context, 0 if scalar context
3541
3542=item * C<$evaltext>
3543
3544The C<eval>() text, if any (undefined for C<eval BLOCK>)
3545
3546=item * C<$is_require>
3547
3548frame was created by a C<use> or C<require> statement
3549
3550=item * C<$hints>
3551
3552pragma information; subject to change between versions
3553
3554=item * C<$bitmask>
3555
be9a9b1d 3556pragma information; subject to change between versions
69893cff
RGS
3557
3558=item * C<@DB::args>
3559
3560arguments with which the subroutine was invoked
3561
3562=back
3563
3564=cut
d338d6fe 3565
6b24a4b7
SF
3566use vars qw($deep);
3567
3568# We need to fully qualify the name ("DB::sub") to make "use strict;"
3569# happy. -- Shlomi Fish
3570sub DB::sub {
b7bfa855
B
3571 # Do not use a regex in this subroutine -> results in corrupted memory
3572 # See: [perl #66110]
69893cff 3573
2cbb2ee1
RGS
3574 # lock ourselves under threads
3575 lock($DBGR);
3576
69893cff
RGS
3577 # Whether or not the autoloader was running, a scalar to put the
3578 # sub's return value in (if needed), and an array to put the sub's
3579 # return value in (if needed).
e22ea7cc 3580 my ( $al, $ret, @ret ) = "";
b7bfa855 3581 if ($sub eq 'threads::new' && $ENV{PERL5DB_THREADED}) {
2cbb2ee1
RGS
3582 print "creating new thread\n";
3583 }
69893cff 3584
c81c05fc 3585 # If the last ten characters are '::AUTOLOAD', note we've traced
69893cff 3586 # into AUTOLOAD for $sub.
e22ea7cc 3587 if ( length($sub) > 10 && substr( $sub, -10, 10 ) eq '::AUTOLOAD' ) {
6b24a4b7 3588 no strict 'refs';
c81c05fc 3589 $al = " for $$sub" if defined $$sub;
d12a4851 3590 }
69893cff
RGS
3591
3592 # We stack the stack pointer and then increment it to protect us
3593 # from a situation that might unwind a whole bunch of call frames
3594 # at once. Localizing the stack pointer means that it will automatically
3595 # unwind the same amount when multiple stack frames are unwound.
e22ea7cc 3596 local $stack_depth = $stack_depth + 1; # Protect from non-local exits
69893cff
RGS
3597
3598 # Expand @stack.
d12a4851 3599 $#stack = $stack_depth;
69893cff
RGS
3600
3601 # Save current single-step setting.
d12a4851 3602 $stack[-1] = $single;
69893cff 3603
e22ea7cc 3604 # Turn off all flags except single-stepping.
d12a4851 3605 $single &= 1;
69893cff
RGS
3606
3607 # If we've gotten really deeply recursed, turn on the flag that will
3608 # make us stop with the 'deep recursion' message.
d12a4851 3609 $single |= 4 if $stack_depth == $deep;
69893cff
RGS
3610
3611 # If frame messages are on ...
3612 (
3613 $frame & 4 # Extended frame entry message
e22ea7cc
RF
3614 ? (
3615 print_lineinfo( ' ' x ( $stack_depth - 1 ), "in " ),
69893cff 3616
e22ea7cc 3617 # Why -1? But it works! :-(
69893cff
RGS
3618 # Because print_trace will call add 1 to it and then call
3619 # dump_trace; this results in our skipping -1+1 = 0 stack frames
3620 # in dump_trace.
e22ea7cc
RF
3621 print_trace( $LINEINFO, -1, 1, 1, "$sub$al" )
3622 )
3623 : print_lineinfo( ' ' x ( $stack_depth - 1 ), "entering $sub$al\n" )
3624
69893cff 3625 # standard frame entry message
e22ea7cc
RF
3626 )
3627 if $frame;
69893cff 3628
98dc9551 3629 # Determine the sub's return type, and capture appropriately.
d12a4851 3630 if (wantarray) {
e22ea7cc 3631
69893cff
RGS
3632 # Called in array context. call sub and capture output.
3633 # DB::DB will recursively get control again if appropriate; we'll come
3634 # back here when the sub is finished.
6b24a4b7
SF
3635 {
3636 no strict 'refs';
3637 @ret = &$sub;
3638 }
69893cff
RGS
3639
3640 # Pop the single-step value back off the stack.
e22ea7cc 3641 $single |= $stack[ $stack_depth-- ];
69893cff
RGS
3642
3643 # Check for exit trace messages...
e22ea7cc
RF
3644 (
3645 $frame & 4 # Extended exit message
3646 ? (
3647 print_lineinfo( ' ' x $stack_depth, "out " ),
3648 print_trace( $LINEINFO, -1, 1, 1, "$sub$al" )
3649 )
3650 : print_lineinfo( ' ' x $stack_depth, "exited $sub$al\n" )
3651
69893cff 3652 # Standard exit message
e22ea7cc
RF
3653 )
3654 if $frame & 2;
69893cff
RGS
3655
3656 # Print the return info if we need to.
e22ea7cc
RF
3657 if ( $doret eq $stack_depth or $frame & 16 ) {
3658
69893cff 3659 # Turn off output record separator.
e22ea7cc
RF
3660 local $\ = '';
3661 my $fh = ( $doret eq $stack_depth ? $OUT : $LINEINFO );
69893cff
RGS
3662
3663 # Indent if we're printing because of $frame tracing.
e22ea7cc 3664 print $fh ' ' x $stack_depth if $frame & 16;
69893cff
RGS
3665
3666 # Print the return value.
e22ea7cc
RF
3667 print $fh "list context return from $sub:\n";
3668 dumpit( $fh, \@ret );
69893cff
RGS
3669
3670 # And don't print it again.
e22ea7cc 3671 $doret = -2;
69893cff 3672 } ## end if ($doret eq $stack_depth...
e22ea7cc
RF
3673 # And we have to return the return value now.
3674 @ret;
69893cff
RGS
3675 } ## end if (wantarray)
3676
3677 # Scalar context.
3678 else {
584420f0 3679 if ( defined wantarray ) {
6b24a4b7 3680 no strict 'refs';
584420f0
RGS
3681 # Save the value if it's wanted at all.
3682 $ret = &$sub;
3683 }
3684 else {