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perl5db: fix an accidental effect of strictures
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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
043fec90 526$VERSION = '1.39_03';
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 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 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
bdba49ad
SF
917# Default to 1 so the prompt will display the first line.
918$trace_to_depth = 1;
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
A
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 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 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 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 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 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 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
1734);
1735
d338d6fe 1736sub DB {
69893cff 1737
2cbb2ee1
RGS
1738 # lock the debugger and get the thread id for the prompt
1739 lock($DBGR);
1740 my $tid;
6b24a4b7
SF
1741 my $position;
1742 my ($prefix, $after, $infix);
1743 my $pat;
1744 my $end;
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.
6b24a4b7 1758 for ( my $i = 0 ; $i <= $stack_depth ; ) {
e22ea7cc
RF
1759 $stack[ $i++ ] &= ~1;
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 if ( $dbline{$line}
e09195af 1808 && _is_breakpoint_enabled($filename, $line)
6b24a4b7 1809 && ( my ( $stop, $action ) = split( /\0/, $dbline{$line} ) ) )
e22ea7cc
RF
1810 {
1811
69893cff 1812 # Stop if the stop criterion says to just stop.
e22ea7cc 1813 if ( $stop eq '1' ) {
69893cff
RGS
1814 $signal |= 1;
1815 }
e22ea7cc 1816
69893cff
RGS
1817 # It's a conditional stop; eval it in the user's context and
1818 # see if we should stop. If so, remove the one-time sigil.
1819 elsif ($stop) {
e22ea7cc 1820 $evalarg = "\$DB::signal |= 1 if do {$stop}";
69893cff 1821 &eval;
5d5d9ea3
SF
1822 # If the breakpoint is temporary, then delete its enabled status.
1823 if ($dbline{$line} =~ s/;9($|\0)/$1/) {
1824 _cancel_breakpoint_temp_enabled_status($filename, $line);
1825 }
69893cff
RGS
1826 }
1827 } ## end if ($dbline{$line} && ...
1828
1829 # Preserve the current stop-or-not, and see if any of the W
1830 # (watch expressions) has changed.
36477c24 1831 my $was_signal = $signal;
69893cff
RGS
1832
1833 # If we have any watch expressions ...
e22ea7cc
RF
1834 if ( $trace & 2 ) {
1835 for ( my $n = 0 ; $n <= $#to_watch ; $n++ ) {
1836 $evalarg = $to_watch[$n];
1837 local $onetimeDump; # Tell DB::eval() to not output results
69893cff
RGS
1838
1839 # Fix context DB::eval() wants to return an array, but
1840 # we need a scalar here.
e22ea7cc
RF
1841 my ($val) = join( "', '", &eval );
1842 $val = ( ( defined $val ) ? "'$val'" : 'undef' );
69893cff
RGS
1843
1844 # Did it change?
e22ea7cc
RF
1845 if ( $val ne $old_watch[$n] ) {
1846
69893cff 1847 # Yep! Show the difference, and fake an interrupt.
e22ea7cc
RF
1848 $signal = 1;
1849 print $OUT <<EOP;
405ff068 1850Watchpoint $n:\t$to_watch[$n] changed:
69893cff
RGS
1851 old value:\t$old_watch[$n]
1852 new value:\t$val
6027b9a3 1853EOP
e22ea7cc 1854 $old_watch[$n] = $val;
69893cff
RGS
1855 } ## end if ($val ne $old_watch...
1856 } ## end for (my $n = 0 ; $n <= ...
1857 } ## end if ($trace & 2)
1858
1859=head2 C<watchfunction()>
1860
1861C<watchfunction()> is a function that can be defined by the user; it is a
1862function which will be run on each entry to C<DB::DB>; it gets the
1863current package, filename, and line as its parameters.
1864
1865The watchfunction can do anything it likes; it is executing in the
1866debugger's context, so it has access to all of the debugger's internal
1867data structures and functions.
1868
1869C<watchfunction()> can control the debugger's actions. Any of the following
1870will cause the debugger to return control to the user's program after
1871C<watchfunction()> executes:
1872
1873=over 4
1874
be9a9b1d
AT
1875=item *
1876
1877Returning a false value from the C<watchfunction()> itself.
1878
1879=item *
1880
1881Altering C<$single> to a false value.
1882
1883=item *
69893cff 1884
be9a9b1d 1885Altering C<$signal> to a false value.
69893cff 1886
be9a9b1d 1887=item *
69893cff 1888
be9a9b1d 1889Turning off the C<4> bit in C<$trace> (this also disables the
69893cff
RGS
1890check for C<watchfunction()>. This can be done with
1891
1892 $trace &= ~4;
1893
1894=back
1895
1896=cut
1897
e22ea7cc 1898 # If there's a user-defined DB::watchfunction, call it with the
69893cff
RGS
1899 # current package, filename, and line. The function executes in
1900 # the DB:: package.
e22ea7cc
RF
1901 if ( $trace & 4 ) { # User-installed watch
1902 return
1903 if watchfunction( $package, $filename, $line )
1904 and not $single
1905 and not $was_signal
1906 and not( $trace & ~4 );
69893cff
RGS
1907 } ## end if ($trace & 4)
1908
e22ea7cc 1909 # Pick up any alteration to $signal in the watchfunction, and
69893cff 1910 # turn off the signal now.
6027b9a3 1911 $was_signal = $signal;
69893cff
RGS
1912 $signal = 0;
1913
1914=head2 GETTING READY TO EXECUTE COMMANDS
1915
1916The debugger decides to take control if single-step mode is on, the
1917C<t> command was entered, or the user generated a signal. If the program
1918has fallen off the end, we set things up so that entering further commands
1919won't cause trouble, and we say that the program is over.
1920
1921=cut
1922
8dc67a69
SF
1923 # Make sure that we always print if asked for explicitly regardless
1924 # of $trace_to_depth .
1925 my $explicit_stop = ($single || $was_signal);
1926
69893cff
RGS
1927 # Check to see if we should grab control ($single true,
1928 # trace set appropriately, or we got a signal).
8dc67a69 1929 if ( $explicit_stop || ( $trace & 1 ) ) {
e22ea7cc 1930
69893cff 1931 # Yes, grab control.
e22ea7cc
RF
1932 if ($slave_editor) {
1933
69893cff 1934 # Tell the editor to update its position.
e22ea7cc
RF
1935 $position = "\032\032$filename:$line:0\n";
1936 print_lineinfo($position);
1937 }
69893cff
RGS
1938
1939=pod
1940
1941Special check: if we're in package C<DB::fake>, we've gone through the
1942C<END> block at least once. We set up everything so that we can continue
1943to enter commands and have a valid context to be in.
1944
1945=cut
1946
e22ea7cc 1947 elsif ( $package eq 'DB::fake' ) {
69893cff 1948
69893cff 1949 # Fallen off the end already.
e22ea7cc
RF
1950 $term || &setterm;
1951 print_help(<<EOP);
405ff068 1952Debugged program terminated. Use B<q> to quit or B<R> to restart,
6b27b0a0
BD
1953 use B<o> I<inhibit_exit> to avoid stopping after program termination,
1954 B<h q>, B<h R> or B<h o> to get additional info.
405ff068 1955EOP
e22ea7cc 1956
69893cff 1957 # Set the DB::eval context appropriately.
e22ea7cc 1958 $package = 'main';
6b24a4b7 1959 $usercontext = _calc_usercontext($package);
69893cff 1960 } ## end elsif ($package eq 'DB::fake')
e219e2fb 1961
69893cff 1962=pod
e219e2fb 1963
69893cff
RGS
1964If the program hasn't finished executing, we scan forward to the
1965next executable line, print that out, build the prompt from the file and line
1966number information, and print that.
e219e2fb 1967
69893cff
RGS
1968=cut
1969
e22ea7cc
RF
1970 else {
1971
8dc67a69 1972
69893cff
RGS
1973 # Still somewhere in the midst of execution. Set up the
1974 # debugger prompt.
1975 $sub =~ s/\'/::/; # Swap Perl 4 package separators (') to
e22ea7cc 1976 # Perl 5 ones (sorry, we don't print Klingon
69893cff
RGS
1977 #module names)
1978
6b24a4b7 1979 $prefix = $sub =~ /::/ ? "" : ($package . '::');
e22ea7cc
RF
1980 $prefix .= "$sub($filename:";
1981 $after = ( $dbline[$line] =~ /\n$/ ? '' : "\n" );
69893cff
RGS
1982
1983 # Break up the prompt if it's really long.
e22ea7cc
RF
1984 if ( length($prefix) > 30 ) {
1985 $position = "$prefix$line):\n$line:\t$dbline[$line]$after";
1986 $prefix = "";
1987 $infix = ":\t";
1988 }
1989 else {
1990 $infix = "):\t";
1991 $position = "$prefix$line$infix$dbline[$line]$after";
1992 }
69893cff
RGS
1993
1994 # Print current line info, indenting if necessary.
e22ea7cc
RF
1995 if ($frame) {
1996 print_lineinfo( ' ' x $stack_depth,
1997 "$line:\t$dbline[$line]$after" );
1998 }
1999 else {
8dc67a69 2000 depth_print_lineinfo($explicit_stop, $position);
e22ea7cc 2001 }
69893cff
RGS
2002
2003 # Scan forward, stopping at either the end or the next
2004 # unbreakable line.
6b24a4b7 2005 for ( my $i = $line + 1 ; $i <= $max && $dbline[$i] == 0 ; ++$i )
e22ea7cc 2006 { #{ vi
69893cff
RGS
2007
2008 # Drop out on null statements, block closers, and comments.
2009 last if $dbline[$i] =~ /^\s*[\;\}\#\n]/;
2010
2011 # Drop out if the user interrupted us.
2012 last if $signal;
2013
2014 # Append a newline if the line doesn't have one. Can happen
2015 # in eval'ed text, for instance.
e22ea7cc 2016 $after = ( $dbline[$i] =~ /\n$/ ? '' : "\n" );
69893cff
RGS
2017
2018 # Next executable line.
6b24a4b7 2019 my $incr_pos = "$prefix$i$infix$dbline[$i]$after";
69893cff
RGS
2020 $position .= $incr_pos;
2021 if ($frame) {
e22ea7cc 2022
69893cff 2023 # Print it indented if tracing is on.
e22ea7cc
RF
2024 print_lineinfo( ' ' x $stack_depth,
2025 "$i:\t$dbline[$i]$after" );
69893cff
RGS
2026 }
2027 else {
8dc67a69 2028 depth_print_lineinfo($explicit_stop, $incr_pos);
69893cff
RGS
2029 }
2030 } ## end for ($i = $line + 1 ; $i...
2031 } ## end else [ if ($slave_editor)
2032 } ## end if ($single || ($trace...
2033
2034=pod
2035
2036If there's an action to be executed for the line we stopped at, execute it.
2037If there are any preprompt actions, execute those as well.
e219e2fb
RF
2038
2039=cut
2040
69893cff
RGS
2041 # If there's an action, do it now.
2042 $evalarg = $action, &eval if $action;
e219e2fb 2043
69893cff
RGS
2044 # Are we nested another level (e.g., did we evaluate a function
2045 # that had a breakpoint in it at the debugger prompt)?
e22ea7cc
RF
2046 if ( $single || $was_signal ) {
2047
69893cff 2048 # Yes, go down a level.
e22ea7cc 2049 local $level = $level + 1;
69893cff
RGS
2050
2051 # Do any pre-prompt actions.
e22ea7cc
RF
2052 foreach $evalarg (@$pre) {
2053 &eval;
2054 }
69893cff
RGS
2055
2056 # Complain about too much recursion if we passed the limit.
e22ea7cc 2057 print $OUT $stack_depth . " levels deep in subroutine calls!\n"
69893cff
RGS
2058 if $single & 4;
2059
2060 # The line we're currently on. Set $incr to -1 to stay here
2061 # until we get a command that tells us to advance.
e22ea7cc
RF
2062 $start = $line;
2063 $incr = -1; # for backward motion.
69893cff
RGS
2064
2065 # Tack preprompt debugger actions ahead of any actual input.
e22ea7cc 2066 @typeahead = ( @$pretype, @typeahead );
69893cff
RGS
2067
2068=head2 WHERE ARE WE?
2069
2070XXX Relocate this section?
2071
2072The debugger normally shows the line corresponding to the current line of
2073execution. Sometimes, though, we want to see the next line, or to move elsewhere
2074in the file. This is done via the C<$incr>, C<$start>, and C<$max> variables.
2075
be9a9b1d
AT
2076C<$incr> controls by how many lines the I<current> line should move forward
2077after a command is executed. If set to -1, this indicates that the I<current>
69893cff
RGS
2078line shouldn't change.
2079
be9a9b1d 2080C<$start> is the I<current> line. It is used for things like knowing where to
69893cff
RGS
2081move forwards or backwards from when doing an C<L> or C<-> command.
2082
2083C<$max> tells the debugger where the last line of the current file is. It's
2084used to terminate loops most often.
2085
2086=head2 THE COMMAND LOOP
2087
2088Most of C<DB::DB> is actually a command parsing and dispatch loop. It comes
2089in two parts:
2090
2091=over 4
2092
be9a9b1d
AT
2093=item *
2094
2095The outer part of the loop, starting at the C<CMD> label. This loop
69893cff
RGS
2096reads a command and then executes it.
2097
be9a9b1d
AT
2098=item *
2099
2100The inner part of the loop, starting at the C<PIPE> label. This part
69893cff
RGS
2101is wholly contained inside the C<CMD> block and only executes a command.
2102Used to handle commands running inside a pager.
2103
2104=back
2105
2106So why have two labels to restart the loop? Because sometimes, it's easier to
2107have a command I<generate> another command and then re-execute the loop to do
2108the new command. This is faster, but perhaps a bit more convoluted.
2109
2110=cut
2111
2112 # The big command dispatch loop. It keeps running until the
2113 # user yields up control again.
2114 #
2115 # If we have a terminal for input, and we get something back
2116 # from readline(), keep on processing.
6b24a4b7
SF
2117 my $piped;
2118 my $selected;
2119
e22ea7cc
RF
2120 CMD:
2121 while (
2122
69893cff 2123 # We have a terminal, or can get one ...
e22ea7cc
RF
2124 ( $term || &setterm ),
2125
69893cff 2126 # ... and it belogs to this PID or we get one for this PID ...
e22ea7cc
RF
2127 ( $term_pid == $$ or resetterm(1) ),
2128
69893cff 2129 # ... and we got a line of command input ...
e22ea7cc
RF
2130 defined(
2131 $cmd = &readline(
2cbb2ee1 2132 "$pidprompt $tid DB"
e22ea7cc
RF
2133 . ( '<' x $level )
2134 . ( $#hist + 1 )
2135 . ( '>' x $level ) . " "
69893cff
RGS
2136 )
2137 )
2138 )
2139 {
e22ea7cc 2140
2cbb2ee1 2141 share($cmd);
69893cff
RGS
2142 # ... try to execute the input as debugger commands.
2143
2144 # Don't stop running.
2145 $single = 0;
2146
2147 # No signal is active.
2148 $signal = 0;
2149
2150 # Handle continued commands (ending with \):
e22ea7cc
RF
2151 $cmd =~ s/\\$/\n/ && do {
2152 $cmd .= &readline(" cont: ");
2153 redo CMD;
2154 };
69893cff
RGS
2155
2156=head4 The null command
2157
be9a9b1d 2158A newline entered by itself means I<re-execute the last command>. We grab the
69893cff
RGS
2159command out of C<$laststep> (where it was recorded previously), and copy it
2160back into C<$cmd> to be executed below. If there wasn't any previous command,
2161we'll do nothing below (no command will match). If there was, we also save it
2162in the command history and fall through to allow the command parsing to pick
2163it up.
2164
2165=cut
2166
2167 # Empty input means repeat the last command.
e22ea7cc
RF
2168 $cmd =~ /^$/ && ( $cmd = $laststep );
2169 chomp($cmd); # get rid of the annoying extra newline
2170 push( @hist, $cmd ) if length($cmd) > 1;
2171 push( @truehist, $cmd );
2cbb2ee1
RGS
2172 share(@hist);
2173 share(@truehist);
e22ea7cc
RF
2174
2175 # This is a restart point for commands that didn't arrive
2176 # via direct user input. It allows us to 'redo PIPE' to
2177 # re-execute command processing without reading a new command.
69893cff 2178 PIPE: {
e22ea7cc
RF
2179 $cmd =~ s/^\s+//s; # trim annoying leading whitespace
2180 $cmd =~ s/\s+$//s; # trim annoying trailing whitespace
6b24a4b7 2181 my ($i) = split( /\s+/, $cmd );
69893cff
RGS
2182
2183=head3 COMMAND ALIASES
2184
2185The debugger can create aliases for commands (these are stored in the
2186C<%alias> hash). Before a command is executed, the command loop looks it up
2187in the alias hash and substitutes the contents of the alias for the command,
2188completely replacing it.
2189
2190=cut
2191
2192 # See if there's an alias for the command, and set it up if so.
e22ea7cc
RF
2193 if ( $alias{$i} ) {
2194
69893cff
RGS
2195 # Squelch signal handling; we want to keep control here
2196 # if something goes loco during the alias eval.
2197 local $SIG{__DIE__};
2198 local $SIG{__WARN__};
2199
2200 # This is a command, so we eval it in the DEBUGGER's
2201 # scope! Otherwise, we can't see the special debugger
2202 # variables, or get to the debugger's subs. (Well, we
2203 # _could_, but why make it even more complicated?)
2204 eval "\$cmd =~ $alias{$i}";
2205 if ($@) {
2206 local $\ = '';
1f874cb6 2207 print $OUT "Couldn't evaluate '$i' alias: $@";
69893cff
RGS
2208 next CMD;
2209 }
2210 } ## end if ($alias{$i})
2211
2212=head3 MAIN-LINE COMMANDS
2213
2214All of these commands work up to and after the program being debugged has
2215terminated.
2216
2217=head4 C<q> - quit
2218
2219Quit the debugger. This entails setting the C<$fall_off_end> flag, so we don't
2220try to execute further, cleaning any restart-related stuff out of the
2221environment, and executing with the last value of C<$?>.
2222
2223=cut
2224
2225 $cmd =~ /^q$/ && do {
2226 $fall_off_end = 1;
2227 clean_ENV();
2228 exit $?;
2229 };
2230
611272bb 2231=head4 C<t> - trace [n]
69893cff
RGS
2232
2233Turn tracing on or off. Inverts the appropriate bit in C<$trace> (q.v.).
611272bb 2234If level is specified, set C<$trace_to_depth>.
69893cff
RGS
2235
2236=cut
2237
611272bb
PS
2238 $cmd =~ /^t(?:\s+(\d+))?$/ && do {
2239 my $levels = $1;
e22ea7cc
RF
2240 $trace ^= 1;
2241 local $\ = '';
611272bb 2242 $trace_to_depth = $levels ? $stack_depth + $levels : 1E9;
e22ea7cc 2243 print $OUT "Trace = "
611272bb
PS
2244 . ( ( $trace & 1 )
2245 ? ( $levels ? "on (to level $trace_to_depth)" : "on" )
2246 : "off" ) . "\n";
e22ea7cc
RF
2247 next CMD;
2248 };
69893cff
RGS
2249
2250=head4 C<S> - list subroutines matching/not matching a pattern
2251
2252Walks through C<%sub>, checking to see whether or not to print the name.
2253
2254=cut
2255
e22ea7cc 2256 $cmd =~ /^S(\s+(!)?(.+))?$/ && do {
69893cff 2257
6b24a4b7
SF
2258 my $Srev = defined $2; # Reverse scan?
2259 my $Spatt = $3; # The pattern (if any) to use.
2260 my $Snocheck = !defined $1; # No args - print all subs.
69893cff
RGS
2261
2262 # Need to make these sane here.
e22ea7cc
RF
2263 local $\ = '';
2264 local $, = '';
69893cff
RGS
2265
2266 # Search through the debugger's magical hash of subs.
2267 # If $nocheck is true, just print the sub name.
2268 # Otherwise, check it against the pattern. We then use
2269 # the XOR trick to reverse the condition as required.
e22ea7cc
RF
2270 foreach $subname ( sort( keys %sub ) ) {
2271 if ( $Snocheck or $Srev ^ ( $subname =~ /$Spatt/ ) ) {
2272 print $OUT $subname, "\n";
2273 }
2274 }
2275 next CMD;
2276 };
69893cff
RGS
2277
2278=head4 C<X> - list variables in current package
2279
2280Since the C<V> command actually processes this, just change this to the
2281appropriate C<V> command and fall through.
2282
2283=cut
2284
e22ea7cc 2285 $cmd =~ s/^X\b/V $package/;
69893cff
RGS
2286
2287=head4 C<V> - list variables
2288
2289Uses C<dumpvar.pl> to dump out the current values for selected variables.
2290
2291=cut
2292
2293 # Bare V commands get the currently-being-debugged package
2294 # added.
e22ea7cc
RF
2295 $cmd =~ /^V$/ && do {
2296 $cmd = "V $package";
2297 };
69893cff
RGS
2298
2299 # V - show variables in package.
2300 $cmd =~ /^V\b\s*(\S+)\s*(.*)/ && do {
e22ea7cc 2301
69893cff
RGS
2302 # Save the currently selected filehandle and
2303 # force output to debugger's filehandle (dumpvar
2304 # just does "print" for output).
6b24a4b7 2305 my $savout = select($OUT);
69893cff
RGS
2306
2307 # Grab package name and variables to dump.
e22ea7cc 2308 $packname = $1;
6b24a4b7 2309 my @vars = split( ' ', $2 );
69893cff
RGS
2310
2311 # If main::dumpvar isn't here, get it.
e81465be 2312 do 'dumpvar.pl' || die $@ unless defined &main::dumpvar;
e22ea7cc
RF
2313 if ( defined &main::dumpvar ) {
2314
69893cff
RGS
2315 # We got it. Turn off subroutine entry/exit messages
2316 # for the moment, along with return values.
e22ea7cc
RF
2317 local $frame = 0;
2318 local $doret = -2;
69893cff
RGS
2319
2320 # must detect sigpipe failures - not catching
2321 # then will cause the debugger to die.
2322 eval {
2323 &main::dumpvar(
2324 $packname,
2325 defined $option{dumpDepth}
e22ea7cc
RF
2326 ? $option{dumpDepth}
2327 : -1, # assume -1 unless specified
69893cff 2328 @vars
e22ea7cc
RF
2329 );
2330 };
2331
2332 # The die doesn't need to include the $@, because
2333 # it will automatically get propagated for us.
2334 if ($@) {
2335 die unless $@ =~ /dumpvar print failed/;
2336 }
2337 } ## end if (defined &main::dumpvar)
2338 else {
2339
2340 # Couldn't load dumpvar.
2341 print $OUT "dumpvar.pl not available.\n";
2342 }
69893cff 2343
69893cff 2344 # Restore the output filehandle, and go round again.
e22ea7cc
RF
2345 select($savout);
2346 next CMD;
2347 };
69893cff
RGS
2348
2349=head4 C<x> - evaluate and print an expression
2350
2351Hands the expression off to C<DB::eval>, setting it up to print the value
2352via C<dumpvar.pl> instead of just printing it directly.
2353
2354=cut
2355
e22ea7cc
RF
2356 $cmd =~ s/^x\b/ / && do { # Remainder gets done by DB::eval()
2357 $onetimeDump = 'dump'; # main::dumpvar shows the output
69893cff
RGS
2358
2359 # handle special "x 3 blah" syntax XXX propagate
2360 # doc back to special variables.
e22ea7cc
RF
2361 if ( $cmd =~ s/^\s*(\d+)(?=\s)/ / ) {
2362 $onetimedumpDepth = $1;
2363 }
2364 };
69893cff
RGS
2365
2366=head4 C<m> - print methods
2367
2368Just uses C<DB::methods> to determine what methods are available.
2369
2370=cut
2371
e22ea7cc
RF
2372 $cmd =~ s/^m\s+([\w:]+)\s*$/ / && do {
2373 methods($1);
2374 next CMD;
2375 };
69893cff
RGS
2376
2377 # m expr - set up DB::eval to do the work
e22ea7cc
RF
2378 $cmd =~ s/^m\b/ / && do { # Rest gets done by DB::eval()
2379 $onetimeDump = 'methods'; # method output gets used there
2380 };
69893cff
RGS
2381
2382=head4 C<f> - switch files
2383
2384=cut
2385
e22ea7cc
RF
2386 $cmd =~ /^f\b\s*(.*)/ && do {
2387 $file = $1;
2388 $file =~ s/\s+$//;
69893cff
RGS
2389
2390 # help for no arguments (old-style was return from sub).
e22ea7cc
RF
2391 if ( !$file ) {
2392 print $OUT
2393 "The old f command is now the r command.\n"; # hint
2394 print $OUT "The new f command switches filenames.\n";
2395 next CMD;
2396 } ## end if (!$file)
69893cff
RGS
2397
2398 # if not in magic file list, try a close match.
e22ea7cc
RF
2399 if ( !defined $main::{ '_<' . $file } ) {
2400 if ( ($try) = grep( m#^_<.*$file#, keys %main:: ) ) {
2401 {
2402 $try = substr( $try, 2 );
1f874cb6 2403 print $OUT "Choosing $try matching '$file':\n";
e22ea7cc
RF
2404 $file = $try;
2405 }
2406 } ## end if (($try) = grep(m#^_<.*$file#...
2407 } ## end if (!defined $main::{ ...
69893cff
RGS
2408
2409 # If not successfully switched now, we failed.
e22ea7cc 2410 if ( !defined $main::{ '_<' . $file } ) {
1f874cb6 2411 print $OUT "No file matching '$file' is loaded.\n";
e22ea7cc
RF
2412 next CMD;
2413 }
69893cff 2414
e22ea7cc
RF
2415 # We switched, so switch the debugger internals around.
2416 elsif ( $file ne $filename ) {
2417 *dbline = $main::{ '_<' . $file };
2418 $max = $#dbline;
2419 $filename = $file;
2420 $start = 1;
2421 $cmd = "l";
2422 } ## end elsif ($file ne $filename)
2423
2424 # We didn't switch; say we didn't.
2425 else {
2426 print $OUT "Already in $file.\n";
2427 next CMD;
2428 }
2429 };
69893cff
RGS
2430
2431=head4 C<.> - return to last-executed line.
2432
2433We set C<$incr> to -1 to indicate that the debugger shouldn't move ahead,
2434and then we look up the line in the magical C<%dbline> hash.
2435
2436=cut
2437
2438 # . command.
e22ea7cc
RF
2439 $cmd =~ /^\.$/ && do {
2440 $incr = -1; # stay at current line
69893cff
RGS
2441
2442 # Reset everything to the old location.
e22ea7cc
RF
2443 $start = $line;
2444 $filename = $filename_ini;
2445 *dbline = $main::{ '_<' . $filename };
2446 $max = $#dbline;
69893cff
RGS
2447
2448 # Now where are we?
e22ea7cc
RF
2449 print_lineinfo($position);
2450 next CMD;
2451 };
69893cff
RGS
2452
2453=head4 C<-> - back one window
2454
2455We change C<$start> to be one window back; if we go back past the first line,
2456we set it to be the first line. We ser C<$incr> to put us back at the
2457currently-executing line, and then put a C<l $start +> (list one window from
2458C<$start>) in C<$cmd> to be executed later.
2459
2460=cut
2461
2462 # - - back a window.
e22ea7cc
RF
2463 $cmd =~ /^-$/ && do {
2464
69893cff 2465 # back up by a window; go to 1 if back too far.
e22ea7cc
RF
2466 $start -= $incr + $window + 1;
2467 $start = 1 if $start <= 0;
2468 $incr = $window - 1;
69893cff
RGS
2469
2470 # Generate and execute a "l +" command (handled below).
e22ea7cc
RF
2471 $cmd = 'l ' . ($start) . '+';
2472 };
69893cff
RGS
2473
2474=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>, {, {{>
2475
2476In Perl 5.8.0, a realignment of the commands was done to fix up a number of
2477problems, most notably that the default case of several commands destroying
2478the user's work in setting watchpoints, actions, etc. We wanted, however, to
2479retain the old commands for those who were used to using them or who preferred
2480them. At this point, we check for the new commands and call C<cmd_wrapper> to
2481deal with them instead of processing them in-line.
2482
2483=cut
2484
2485 # All of these commands were remapped in perl 5.8.0;
e22ea7cc 2486 # we send them off to the secondary dispatcher (see below).
2cbb2ee1 2487 $cmd =~ /^([aAbBeEhilLMoOPvwW]\b|[<>\{]{1,2})\s*(.*)/so && do {
e22ea7cc
RF
2488 &cmd_wrapper( $1, $2, $line );
2489 next CMD;
2490 };
69893cff
RGS
2491
2492=head4 C<y> - List lexicals in higher scope
2493
2494Uses C<PadWalker> to find the lexicals supplied as arguments in a scope
2495above the current one and then displays then using C<dumpvar.pl>.
2496
2497=cut
2498
2499 $cmd =~ /^y(?:\s+(\d*)\s*(.*))?$/ && do {
2500
2501 # See if we've got the necessary support.
2502 eval { require PadWalker; PadWalker->VERSION(0.08) }
2503 or &warn(
2504 $@ =~ /locate/
2505 ? "PadWalker module not found - please install\n"
2506 : $@
2507 )
2508 and next CMD;
2509
2510 # Load up dumpvar if we don't have it. If we can, that is.
e81465be 2511 do 'dumpvar.pl' || die $@ unless defined &main::dumpvar;
69893cff
RGS
2512 defined &main::dumpvar
2513 or print $OUT "dumpvar.pl not available.\n"
2514 and next CMD;
2515
2516 # Got all the modules we need. Find them and print them.
e22ea7cc 2517 my @vars = split( ' ', $2 || '' );
69893cff
RGS
2518
2519 # Find the pad.
e22ea7cc 2520 my $h = eval { PadWalker::peek_my( ( $1 || 0 ) + 1 ) };
69893cff
RGS
2521
2522 # Oops. Can't find it.
2523 $@ and $@ =~ s/ at .*//, &warn($@), next CMD;
2524
2525 # Show the desired vars with dumplex().
2526 my $savout = select($OUT);
2527
2528 # Have dumplex dump the lexicals.
e22ea7cc 2529 dumpvar::dumplex( $_, $h->{$_},
69893cff 2530 defined $option{dumpDepth} ? $option{dumpDepth} : -1,
e22ea7cc
RF
2531 @vars )
2532 for sort keys %$h;
69893cff
RGS
2533 select($savout);
2534 next CMD;
2535 };
2536
2537=head3 COMMANDS NOT WORKING AFTER PROGRAM ENDS
2538
2539All of the commands below this point don't work after the program being
2540debugged has ended. All of them check to see if the program has ended; this
2541allows the commands to be relocated without worrying about a 'line of
2542demarcation' above which commands can be entered anytime, and below which
2543they can't.
2544
2545=head4 C<n> - single step, but don't trace down into subs
2546
2547Done by setting C<$single> to 2, which forces subs to execute straight through
be9a9b1d 2548when entered (see C<DB::sub>). We also save the C<n> command in C<$laststep>,
69893cff
RGS
2549so a null command knows what to re-execute.
2550
2551=cut
2552
e22ea7cc 2553 # n - next
69893cff
RGS
2554 $cmd =~ /^n$/ && do {
2555 end_report(), next CMD if $finished and $level <= 1;
e22ea7cc 2556
69893cff
RGS
2557 # Single step, but don't enter subs.
2558 $single = 2;
e22ea7cc 2559
69893cff 2560 # Save for empty command (repeat last).
e22ea7cc
RF
2561 $laststep = $cmd;
2562 last CMD;
2563 };
69893cff
RGS
2564
2565=head4 C<s> - single-step, entering subs
2566
be9a9b1d 2567Sets C<$single> to 1, which causes C<DB::sub> to continue tracing inside
69893cff
RGS
2568subs. Also saves C<s> as C<$lastcmd>.
2569
2570=cut
2571
2572 # s - single step.
2573 $cmd =~ /^s$/ && do {
e22ea7cc 2574
69893cff
RGS
2575 # Get out and restart the command loop if program
2576 # has finished.
e22ea7cc
RF
2577 end_report(), next CMD if $finished and $level <= 1;
2578
69893cff 2579 # Single step should enter subs.
e22ea7cc
RF
2580 $single = 1;
2581
69893cff 2582 # Save for empty command (repeat last).
e22ea7cc
RF
2583 $laststep = $cmd;
2584 last CMD;
2585 };
69893cff
RGS
2586
2587=head4 C<c> - run continuously, setting an optional breakpoint
2588
2589Most of the code for this command is taken up with locating the optional
2590breakpoint, which is either a subroutine name or a line number. We set
2591the appropriate one-time-break in C<@dbline> and then turn off single-stepping
2592in this and all call levels above this one.
2593
2594=cut
2595
2596 # c - start continuous execution.
2597 $cmd =~ /^c\b\s*([\w:]*)\s*$/ && do {
e22ea7cc 2598
69893cff
RGS
2599 # Hey, show's over. The debugged program finished
2600 # executing already.
2601 end_report(), next CMD if $finished and $level <= 1;
2602
2603 # Capture the place to put a one-time break.
2604 $subname = $i = $1;
2605
e22ea7cc
RF
2606 # Probably not needed, since we finish an interactive
2607 # sub-session anyway...
2608 # local $filename = $filename;
2609 # local *dbline = *dbline; # XXX Would this work?!
69893cff
RGS
2610 #
2611 # The above question wonders if localizing the alias
2612 # to the magic array works or not. Since it's commented
2613 # out, we'll just leave that to speculation for now.
2614
2615 # If the "subname" isn't all digits, we'll assume it
2616 # is a subroutine name, and try to find it.
e22ea7cc
RF
2617 if ( $subname =~ /\D/ ) { # subroutine name
2618 # Qualify it to the current package unless it's
2619 # already qualified.
69893cff
RGS
2620 $subname = $package . "::" . $subname
2621 unless $subname =~ /::/;
e22ea7cc 2622
69893cff
RGS
2623 # find_sub will return "file:line_number" corresponding
2624 # to where the subroutine is defined; we call find_sub,
e22ea7cc 2625 # break up the return value, and assign it in one
69893cff 2626 # operation.
e22ea7cc 2627 ( $file, $i ) = ( find_sub($subname) =~ /^(.*):(.*)$/ );
69893cff
RGS
2628
2629 # Force the line number to be numeric.
e22ea7cc 2630 $i += 0;
69893cff
RGS
2631
2632 # If we got a line number, we found the sub.
e22ea7cc
RF
2633 if ($i) {
2634
69893cff
RGS
2635 # Switch all the debugger's internals around so
2636 # we're actually working with that file.
e22ea7cc
RF
2637 $filename = $file;
2638 *dbline = $main::{ '_<' . $filename };
2639
69893cff 2640 # Mark that there's a breakpoint in this file.
e22ea7cc
RF
2641 $had_breakpoints{$filename} |= 1;
2642
69893cff
RGS
2643 # Scan forward to the first executable line
2644 # after the 'sub whatever' line.
e22ea7cc
RF
2645 $max = $#dbline;
2646 ++$i while $dbline[$i] == 0 && $i < $max;
2647 } ## end if ($i)
69893cff
RGS
2648
2649 # We didn't find a sub by that name.
e22ea7cc
RF
2650 else {
2651 print $OUT "Subroutine $subname not found.\n";
2652 next CMD;
2653 }
2654 } ## end if ($subname =~ /\D/)
69893cff
RGS
2655
2656 # At this point, either the subname was all digits (an
2657 # absolute line-break request) or we've scanned through
2658 # the code following the definition of the sub, looking
2659 # for an executable, which we may or may not have found.
2660 #
2661 # If $i (which we set $subname from) is non-zero, we
e22ea7cc
RF
2662 # got a request to break at some line somewhere. On
2663 # one hand, if there wasn't any real subroutine name
2664 # involved, this will be a request to break in the current
2665 # file at the specified line, so we have to check to make
69893cff
RGS
2666 # sure that the line specified really is breakable.
2667 #
2668 # On the other hand, if there was a subname supplied, the
3c4b39be 2669 # preceding block has moved us to the proper file and
69893cff
RGS
2670 # location within that file, and then scanned forward
2671 # looking for the next executable line. We have to make
2672 # sure that one was found.
2673 #
2674 # On the gripping hand, we can't do anything unless the
2675 # current value of $i points to a valid breakable line.
2676 # Check that.
e22ea7cc
RF
2677 if ($i) {
2678
69893cff 2679 # Breakable?
e22ea7cc
RF
2680 if ( $dbline[$i] == 0 ) {
2681 print $OUT "Line $i not breakable.\n";
2682 next CMD;
2683 }
2684
69893cff 2685 # Yes. Set up the one-time-break sigil.
e22ea7cc 2686 $dbline{$i} =~ s/($|\0)/;9$1/; # add one-time-only b.p.
5d5d9ea3 2687 _enable_breakpoint_temp_enabled_status($filename, $i);
e22ea7cc 2688 } ## end if ($i)
69893cff
RGS
2689
2690 # Turn off stack tracing from here up.
e22ea7cc
RF
2691 for ( $i = 0 ; $i <= $stack_depth ; ) {
2692 $stack[ $i++ ] &= ~1;
2693 }
2694 last CMD;
2695 };
69893cff
RGS
2696
2697=head4 C<r> - return from a subroutine
2698
2699For C<r> to work properly, the debugger has to stop execution again
2700immediately after the return is executed. This is done by forcing
2701single-stepping to be on in the call level above the current one. If
2702we are printing return values when a C<r> is executed, set C<$doret>
2703appropriately, and force us out of the command loop.
2704
2705=cut
2706
2707 # r - return from the current subroutine.
e22ea7cc
RF
2708 $cmd =~ /^r$/ && do {
2709
98dc9551 2710 # Can't do anything if the program's over.
e22ea7cc
RF
2711 end_report(), next CMD if $finished and $level <= 1;
2712
69893cff 2713 # Turn on stack trace.
e22ea7cc
RF
2714 $stack[$stack_depth] |= 1;
2715
69893cff 2716 # Print return value unless the stack is empty.
e22ea7cc
RF
2717 $doret = $option{PrintRet} ? $stack_depth - 1 : -2;
2718 last CMD;
2719 };
69893cff 2720
69893cff
RGS
2721=head4 C<T> - stack trace
2722
2723Just calls C<DB::print_trace>.
2724
2725=cut
2726
e22ea7cc
RF
2727 $cmd =~ /^T$/ && do {
2728 print_trace( $OUT, 1 ); # skip DB
2729 next CMD;
2730 };
69893cff
RGS
2731
2732=head4 C<w> - List window around current line.
2733
2734Just calls C<DB::cmd_w>.
2735
2736=cut
2737
e22ea7cc 2738 $cmd =~ /^w\b\s*(.*)/s && do { &cmd_w( 'w', $1 ); next CMD; };
69893cff
RGS
2739
2740=head4 C<W> - watch-expression processing.
2741
2742Just calls C<DB::cmd_W>.
2743
2744=cut
2745
e22ea7cc 2746 $cmd =~ /^W\b\s*(.*)/s && do { &cmd_W( 'W', $1 ); next CMD; };
69893cff
RGS
2747
2748=head4 C</> - search forward for a string in the source
2749
2750We take the argument and treat it as a pattern. If it turns out to be a
2751bad one, we return the error we got from trying to C<eval> it and exit.
2752If not, we create some code to do the search and C<eval> it so it can't
2753mess us up.
2754
2755=cut
2756
e22ea7cc 2757 $cmd =~ /^\/(.*)$/ && do {
69893cff
RGS
2758
2759 # The pattern as a string.
6b24a4b7 2760 my $inpat = $1;
69893cff
RGS
2761
2762 # Remove the final slash.
e22ea7cc 2763 $inpat =~ s:([^\\])/$:$1:;
69893cff
RGS
2764
2765 # If the pattern isn't null ...
e22ea7cc 2766 if ( $inpat ne "" ) {
69893cff
RGS
2767
2768 # Turn of warn and die procesing for a bit.
e22ea7cc
RF
2769 local $SIG{__DIE__};
2770 local $SIG{__WARN__};
69893cff
RGS
2771
2772 # Create the pattern.
e22ea7cc
RF
2773 eval '$inpat =~ m' . "\a$inpat\a";
2774 if ( $@ ne "" ) {
2775
69893cff 2776 # Oops. Bad pattern. No biscuit.
e22ea7cc 2777 # Print the eval error and go back for more
69893cff 2778 # commands.
e22ea7cc
RF
2779 print $OUT "$@";
2780 next CMD;
2781 }
2782 $pat = $inpat;
2783 } ## end if ($inpat ne "")
69893cff
RGS
2784
2785 # Set up to stop on wrap-around.
e22ea7cc 2786 $end = $start;
69893cff
RGS
2787
2788 # Don't move off the current line.
e22ea7cc 2789 $incr = -1;
69893cff
RGS
2790
2791 # Done in eval so nothing breaks if the pattern
2792 # does something weird.
e22ea7cc
RF
2793 eval '
2794 for (;;) {
69893cff 2795 # Move ahead one line.
e22ea7cc 2796 ++$start;
69893cff
RGS
2797
2798 # Wrap if we pass the last line.
e22ea7cc 2799 $start = 1 if ($start > $max);
69893cff
RGS
2800
2801 # Stop if we have gotten back to this line again,
e22ea7cc 2802 last if ($start == $end);
69893cff
RGS
2803
2804 # A hit! (Note, though, that we are doing
2805 # case-insensitive matching. Maybe a qr//
2806 # expression would be better, so the user could
2807 # do case-sensitive matching if desired.
e22ea7cc
RF
2808 if ($dbline[$start] =~ m' . "\a$pat\a" . 'i) {
2809 if ($slave_editor) {
69893cff 2810 # Handle proper escaping in the slave.
e22ea7cc
RF
2811 print $OUT "\032\032$filename:$start:0\n";
2812 }
2813 else {
69893cff 2814 # Just print the line normally.
e22ea7cc
RF
2815 print $OUT "$start:\t",$dbline[$start],"\n";
2816 }
69893cff 2817 # And quit since we found something.
e22ea7cc
RF
2818 last;
2819 }
2820 } ';
2821
69893cff 2822 # If we wrapped, there never was a match.
e22ea7cc
RF
2823 print $OUT "/$pat/: not found\n" if ( $start == $end );
2824 next CMD;
2825 };
69893cff
RGS
2826
2827=head4 C<?> - search backward for a string in the source
2828
2829Same as for C</>, except the loop runs backwards.
2830
2831=cut
2832
2833 # ? - backward pattern search.
e22ea7cc 2834 $cmd =~ /^\?(.*)$/ && do {
69893cff
RGS
2835
2836 # Get the pattern, remove trailing question mark.
6b24a4b7 2837 my $inpat = $1;
e22ea7cc 2838 $inpat =~ s:([^\\])\?$:$1:;
69893cff
RGS
2839
2840 # If we've got one ...
e22ea7cc 2841 if ( $inpat ne "" ) {
69893cff
RGS
2842
2843 # Turn off die & warn handlers.
e22ea7cc
RF
2844 local $SIG{__DIE__};
2845 local $SIG{__WARN__};
2846 eval '$inpat =~ m' . "\a$inpat\a";
2847
2848 if ( $@ ne "" ) {
2849
69893cff 2850 # Ouch. Not good. Print the error.
e22ea7cc
RF
2851 print $OUT $@;
2852 next CMD;
2853 }
2854 $pat = $inpat;
69893cff 2855 } ## end if ($inpat ne "")
e22ea7cc 2856
69893cff 2857 # Where we are now is where to stop after wraparound.
e22ea7cc 2858 $end = $start;
69893cff
RGS
2859
2860 # Don't move away from this line.
e22ea7cc 2861 $incr = -1;
69893cff
RGS
2862
2863 # Search inside the eval to prevent pattern badness
2864 # from killing us.
e22ea7cc
RF
2865 eval '
2866 for (;;) {
69893cff 2867 # Back up a line.
e22ea7cc 2868 --$start;
69893cff
RGS
2869
2870 # Wrap if we pass the first line.
e22ea7cc
RF
2871
2872 $start = $max if ($start <= 0);
69893cff
RGS
2873
2874 # Quit if we get back where we started,
e22ea7cc 2875 last if ($start == $end);
69893cff
RGS
2876
2877 # Match?
e22ea7cc
RF
2878 if ($dbline[$start] =~ m' . "\a$pat\a" . 'i) {
2879 if ($slave_editor) {
69893cff 2880 # Yep, follow slave editor requirements.
e22ea7cc
RF
2881 print $OUT "\032\032$filename:$start:0\n";
2882 }
2883 else {
69893cff 2884 # Yep, just print normally.
e22ea7cc
RF
2885 print $OUT "$start:\t",$dbline[$start],"\n";
2886 }
69893cff
RGS
2887
2888 # Found, so done.
e22ea7cc
RF
2889 last;
2890 }
2891 } ';
2892
2893 # Say we failed if the loop never found anything,
2894 print $OUT "?$pat?: not found\n" if ( $start == $end );
2895 next CMD;
2896 };
69893cff
RGS
2897
2898=head4 C<$rc> - Recall command
2899
2900Manages the commands in C<@hist> (which is created if C<Term::ReadLine> reports
2901that the terminal supports history). It find the the command required, puts it
2902into C<$cmd>, and redoes the loop to execute it.
2903
2904=cut
2905
e22ea7cc
RF
2906 # $rc - recall command.
2907 $cmd =~ /^$rc+\s*(-)?(\d+)?$/ && do {
69893cff
RGS
2908
2909 # No arguments, take one thing off history.
e22ea7cc 2910 pop(@hist) if length($cmd) > 1;
69893cff 2911
e22ea7cc 2912 # Relative (- found)?
69893cff 2913 # Y - index back from most recent (by 1 if bare minus)
e22ea7cc 2914 # N - go to that particular command slot or the last
69893cff 2915 # thing if nothing following.
e22ea7cc 2916 $i = $1 ? ( $#hist - ( $2 || 1 ) ) : ( $2 || $#hist );
69893cff
RGS
2917
2918 # Pick out the command desired.
e22ea7cc 2919 $cmd = $hist[$i];
69893cff
RGS
2920
2921 # Print the command to be executed and restart the loop
2922 # with that command in the buffer.
e22ea7cc
RF
2923 print $OUT $cmd, "\n";
2924 redo CMD;
2925 };
69893cff
RGS
2926
2927=head4 C<$sh$sh> - C<system()> command
2928
2929Calls the C<DB::system()> to handle the command. This keeps the C<STDIN> and
2930C<STDOUT> from getting messed up.
2931
2932=cut
2933
2934 # $sh$sh - run a shell command (if it's all ASCII).
2935 # Can't run shell commands with Unicode in the debugger, hmm.
e22ea7cc
RF
2936 $cmd =~ /^$sh$sh\s*([\x00-\xff]*)/ && do {
2937
69893cff 2938 # System it.
e22ea7cc
RF
2939 &system($1);
2940 next CMD;
2941 };
69893cff
RGS
2942
2943=head4 C<$rc I<pattern> $rc> - Search command history
2944
2945Another command to manipulate C<@hist>: this one searches it with a pattern.
be9a9b1d 2946If a command is found, it is placed in C<$cmd> and executed via C<redo>.
69893cff
RGS
2947
2948=cut
2949
e22ea7cc
RF
2950 # $rc pattern $rc - find a command in the history.
2951 $cmd =~ /^$rc([^$rc].*)$/ && do {
2952
69893cff 2953 # Create the pattern to use.
e22ea7cc 2954 $pat = "^$1";
69893cff
RGS
2955
2956 # Toss off last entry if length is >1 (and it always is).
e22ea7cc 2957 pop(@hist) if length($cmd) > 1;
69893cff
RGS
2958
2959 # Look backward through the history.
e22ea7cc
RF
2960 for ( $i = $#hist ; $i ; --$i ) {
2961
69893cff 2962 # Stop if we find it.
e22ea7cc
RF
2963 last if $hist[$i] =~ /$pat/;
2964 }
2965
2966 if ( !$i ) {
69893cff 2967
69893cff 2968 # Never found it.
e22ea7cc
RF
2969 print $OUT "No such command!\n\n";
2970 next CMD;
2971 }
69893cff
RGS
2972
2973 # Found it. Put it in the buffer, print it, and process it.
e22ea7cc
RF
2974 $cmd = $hist[$i];
2975 print $OUT $cmd, "\n";
2976 redo CMD;
2977 };
69893cff
RGS
2978
2979=head4 C<$sh> - Invoke a shell
2980
2981Uses C<DB::system> to invoke a shell.
2982
2983=cut
2984
2985 # $sh - start a shell.
e22ea7cc
RF
2986 $cmd =~ /^$sh$/ && do {
2987
69893cff
RGS
2988 # Run the user's shell. If none defined, run Bourne.
2989 # We resume execution when the shell terminates.
e22ea7cc
RF
2990 &system( $ENV{SHELL} || "/bin/sh" );
2991 next CMD;
2992 };
69893cff
RGS
2993
2994=head4 C<$sh I<command>> - Force execution of a command in a shell
2995
2996Like the above, but the command is passed to the shell. Again, we use
2997C<DB::system> to avoid problems with C<STDIN> and C<STDOUT>.
2998
2999=cut
3000
3001 # $sh command - start a shell and run a command in it.
e22ea7cc
RF
3002 $cmd =~ /^$sh\s*([\x00-\xff]*)/ && do {
3003
3004 # XXX: using csh or tcsh destroys sigint retvals!
3005 #&system($1); # use this instead
69893cff
RGS
3006
3007 # use the user's shell, or Bourne if none defined.
e22ea7cc
RF
3008 &system( $ENV{SHELL} || "/bin/sh", "-c", $1 );
3009 next CMD;
3010 };
69893cff
RGS
3011
3012=head4 C<H> - display commands in history
3013
3014Prints the contents of C<@hist> (if any).
3015
3016=cut
3017
7fddc82f
RF
3018 $cmd =~ /^H\b\s*\*/ && do {
3019 @hist = @truehist = ();
3020 print $OUT "History cleansed\n";
3021 next CMD;
3022 };
e22ea7cc
RF
3023
3024 $cmd =~ /^H\b\s*(-(\d+))?/ && do {
3025
3026 # Anything other than negative numbers is ignored by
69893cff 3027 # the (incorrect) pattern, so this test does nothing.
e22ea7cc 3028 $end = $2 ? ( $#hist - $2 ) : 0;
69893cff
RGS
3029
3030 # Set to the minimum if less than zero.
e22ea7cc 3031 $hist = 0 if $hist < 0;
69893cff 3032
e22ea7cc 3033 # Start at the end of the array.
69893cff
RGS
3034 # Stay in while we're still above the ending value.
3035 # Tick back by one each time around the loop.
e22ea7cc 3036 for ( $i = $#hist ; $i > $end ; $i-- ) {
69893cff
RGS
3037
3038 # Print the command unless it has no arguments.
e22ea7cc
RF
3039 print $OUT "$i: ", $hist[$i], "\n"
3040 unless $hist[$i] =~ /^.?$/;
3041 }
3042 next CMD;
3043 };
69893cff
RGS
3044
3045=head4 C<man, doc, perldoc> - look up documentation
3046
3047Just calls C<runman()> to print the appropriate document.
3048
3049=cut
3050
e22ea7cc
RF
3051 # man, perldoc, doc - show manual pages.
3052 $cmd =~ /^(?:man|(?:perl)?doc)\b(?:\s+([^(]*))?$/ && do {
3053 runman($1);
3054 next CMD;
3055 };
69893cff
RGS
3056
3057=head4 C<p> - print
3058
3059Builds a C<print EXPR> expression in the C<$cmd>; this will get executed at
3060the bottom of the loop.
3061
3062=cut
3063
3064 # p - print (no args): print $_.
e22ea7cc 3065 $cmd =~ s/^p$/print {\$DB::OUT} \$_/;
69893cff
RGS
3066
3067 # p - print the given expression.
e22ea7cc 3068 $cmd =~ s/^p\b/print {\$DB::OUT} /;
69893cff
RGS
3069
3070=head4 C<=> - define command alias
3071
3072Manipulates C<%alias> to add or list command aliases.
3073
3074=cut
3075
e22ea7cc
RF
3076 # = - set up a command alias.
3077 $cmd =~ s/^=\s*// && do {
3078 my @keys;
3079 if ( length $cmd == 0 ) {
3080
69893cff 3081 # No args, get current aliases.
e22ea7cc
RF
3082 @keys = sort keys %alias;
3083 }
3084 elsif ( my ( $k, $v ) = ( $cmd =~ /^(\S+)\s+(\S.*)/ ) ) {
3085
69893cff
RGS
3086 # Creating a new alias. $k is alias name, $v is
3087 # alias value.
3088
e22ea7cc
RF
3089 # can't use $_ or kill //g state
3090 for my $x ( $k, $v ) {
3091
3092 # Escape "alarm" characters.
3093 $x =~ s/\a/\\a/g;
3094 }
69893cff
RGS
3095
3096 # Substitute key for value, using alarm chars
e22ea7cc 3097 # as separators (which is why we escaped them in
69893cff 3098 # the command).
e22ea7cc 3099 $alias{$k} = "s\a$k\a$v\a";
69893cff
RGS
3100
3101 # Turn off standard warn and die behavior.
e22ea7cc
RF
3102 local $SIG{__DIE__};
3103 local $SIG{__WARN__};
69893cff
RGS
3104
3105 # Is it valid Perl?
e22ea7cc
RF
3106 unless ( eval "sub { s\a$k\a$v\a }; 1" ) {
3107
69893cff 3108 # Nope. Bad alias. Say so and get out.
e22ea7cc
RF
3109 print $OUT "Can't alias $k to $v: $@\n";
3110 delete $alias{$k};
3111 next CMD;
3112 }
3113
69893cff 3114 # We'll only list the new one.
e22ea7cc 3115 @keys = ($k);
69893cff
RGS
3116 } ## end elsif (my ($k, $v) = ($cmd...
3117
3118 # The argument is the alias to list.
e22ea7cc
RF
3119 else {
3120 @keys = ($cmd);
3121 }
69893cff
RGS
3122
3123 # List aliases.
e22ea7cc
RF
3124 for my $k (@keys) {
3125
98dc9551 3126 # Messy metaquoting: Trim the substitution code off.
69893cff
RGS
3127 # We use control-G as the delimiter because it's not
3128 # likely to appear in the alias.
e22ea7cc
RF
3129 if ( ( my $v = $alias{$k} ) =~ s\as\a$k\a(.*)\a$\a1\a ) {
3130
69893cff 3131 # Print the alias.
e22ea7cc
RF
3132 print $OUT "$k\t= $1\n";
3133 }
3134 elsif ( defined $alias{$k} ) {
3135
69893cff 3136 # Couldn't trim it off; just print the alias code.
e22ea7cc
RF
3137 print $OUT "$k\t$alias{$k}\n";
3138 }
3139 else {
3140
69893cff 3141 # No such, dude.
e22ea7cc
RF
3142 print "No alias for $k\n";
3143 }
69893cff 3144 } ## end for my $k (@keys)
e22ea7cc
RF
3145 next CMD;
3146 };
69893cff
RGS
3147
3148=head4 C<source> - read commands from a file.
3149
3150Opens a lexical filehandle and stacks it on C<@cmdfhs>; C<DB::readline> will
3151pick it up.
3152
3153=cut
3154
e22ea7cc
RF
3155 # source - read commands from a file (or pipe!) and execute.
3156 $cmd =~ /^source\s+(.*\S)/ && do {
3157 if ( open my $fh, $1 ) {
3158
69893cff 3159 # Opened OK; stick it in the list of file handles.
e22ea7cc
RF
3160 push @cmdfhs, $fh;
3161 }
3162 else {
3163
3164 # Couldn't open it.
1f874cb6 3165 &warn("Can't execute '$1': $!\n");
e22ea7cc
RF
3166 }
3167 next CMD;
3168 };
69893cff 3169
e09195af
SF
3170 $cmd =~ /^(enable|disable)\s+(\S+)\s*$/ && do {
3171 my ($cmd, $position) = ($1, $2);
3172
3173 my ($fn, $line_num);
3174 if ($position =~ m{\A\d+\z})
3175 {
3176 $fn = $filename;
3177 $line_num = $position;
3178 }
3179 elsif ($position =~ m{\A(.*):(\d+)\z})
3180 {
3181 ($fn, $line_num) = ($1, $2);
3182 }
3183 else
3184 {
3185 &warn("Wrong spec for enable/disable argument.\n");
3186 }
3187
3188 if (defined($fn)) {
3189 if (_has_breakpoint_data_ref($fn, $line_num)) {
3190 _set_breakpoint_enabled_status($fn, $line_num,
3191 ($cmd eq 'enable' ? 1 : '')
3192 );
3193 }
3194 else {
3195 &warn("No breakpoint set at ${fn}:${line_num}\n");
3196 }
3197 }
3198
3199 next CMD;
3200 };
3201
69893cff
RGS
3202=head4 C<save> - send current history to a file
3203
3204Takes the complete history, (not the shrunken version you see with C<H>),
3205and saves it to the given filename, so it can be replayed using C<source>.
3206
3207Note that all C<^(save|source)>'s are commented out with a view to minimise recursion.
3208
3209=cut
3210
3211 # save source - write commands to a file for later use
3212 $cmd =~ /^save\s*(.*)$/ && do {
e22ea7cc
RF
3213 my $file = $1 || '.perl5dbrc'; # default?
3214 if ( open my $fh, "> $file" ) {
3215
3216 # chomp to remove extraneous newlines from source'd files
3217 chomp( my @truelist =
3218 map { m/^\s*(save|source)/ ? "#$_" : $_ }
3219 @truehist );
3220 print $fh join( "\n", @truelist );
69893cff 3221 print "commands saved in $file\n";
e22ea7cc
RF
3222 }
3223 else {
69893cff
RGS
3224 &warn("Can't save debugger commands in '$1': $!\n");
3225 }
3226 next CMD;
3227 };
3228
7fddc82f
RF
3229=head4 C<R> - restart
3230
3231Restart the debugger session.
3232
3233=head4 C<rerun> - rerun the current session
3234
3235Return to any given position in the B<true>-history list
3236
3237=cut
3238
3239 # R - restart execution.
3240 # rerun - controlled restart execution.
3241 $cmd =~ /^(R|rerun\s*(.*))$/ && do {
3242 my @args = ($1 eq 'R' ? restart() : rerun($2));
3243
ca28b541
AP
3244 # Close all non-system fds for a clean restart. A more
3245 # correct method would be to close all fds that were not
3246 # open when the process started, but this seems to be
3247 # hard. See "debugger 'R'estart and open database
3248 # connections" on p5p.
3249
47d3bbda 3250 my $max_fd = 1024; # default if POSIX can't be loaded
ca28b541 3251 if (eval { require POSIX }) {
5332cc68 3252 eval { $max_fd = POSIX::sysconf(POSIX::_SC_OPEN_MAX()) };
ca28b541
AP
3253 }
3254
3255 if (defined $max_fd) {
3256 foreach ($^F+1 .. $max_fd-1) {
3257 next unless open FD_TO_CLOSE, "<&=$_";
3258 close(FD_TO_CLOSE);
3259 }
3260 }
3261
7fddc82f
RF
3262 # And run Perl again. We use exec() to keep the
3263 # PID stable (and that way $ini_pids is still valid).
3264 exec(@args) || print $OUT "exec failed: $!\n";
3265
3266 last CMD;
3267 };
3268
69893cff
RGS
3269=head4 C<|, ||> - pipe output through the pager.
3270
be9a9b1d 3271For C<|>, we save C<OUT> (the debugger's output filehandle) and C<STDOUT>
69893cff
RGS
3272(the program's standard output). For C<||>, we only save C<OUT>. We open a
3273pipe to the pager (restoring the output filehandles if this fails). If this
3274is the C<|> command, we also set up a C<SIGPIPE> handler which will simply
3275set C<$signal>, sending us back into the debugger.
3276
3277We then trim off the pipe symbols and C<redo> the command loop at the
3278C<PIPE> label, causing us to evaluate the command in C<$cmd> without
3279reading another.
3280
3281=cut
3282
3283 # || - run command in the pager, with output to DB::OUT.
e22ea7cc
RF
3284 $cmd =~ /^\|\|?\s*[^|]/ && do {
3285 if ( $pager =~ /^\|/ ) {
3286
69893cff 3287 # Default pager is into a pipe. Redirect I/O.
e22ea7cc
RF
3288 open( SAVEOUT, ">&STDOUT" )
3289 || &warn("Can't save STDOUT");
3290 open( STDOUT, ">&OUT" )
3291 || &warn("Can't redirect STDOUT");
69893cff 3292 } ## end if ($pager =~ /^\|/)
e22ea7cc
RF
3293 else {
3294
69893cff 3295 # Not into a pipe. STDOUT is safe.
e22ea7cc
RF
3296 open( SAVEOUT, ">&OUT" ) || &warn("Can't save DB::OUT");
3297 }
69893cff
RGS
3298
3299 # Fix up environment to record we have less if so.
e22ea7cc
RF
3300 fix_less();
3301
3302 unless ( $piped = open( OUT, $pager ) ) {
69893cff 3303
69893cff 3304 # Couldn't open pipe to pager.
1f874cb6 3305 &warn("Can't pipe output to '$pager'");
e22ea7cc
RF
3306 if ( $pager =~ /^\|/ ) {
3307
69893cff 3308 # Redirect I/O back again.
e22ea7cc
RF
3309 open( OUT, ">&STDOUT" ) # XXX: lost message
3310 || &warn("Can't restore DB::OUT");
3311 open( STDOUT, ">&SAVEOUT" )
3312 || &warn("Can't restore STDOUT");
3313 close(SAVEOUT);
69893cff 3314 } ## end if ($pager =~ /^\|/)
e22ea7cc
RF
3315 else {
3316
69893cff 3317 # Redirect I/O. STDOUT already safe.
e22ea7cc
RF
3318 open( OUT, ">&STDOUT" ) # XXX: lost message
3319 || &warn("Can't restore DB::OUT");
3320 }
3321 next CMD;
69893cff
RGS
3322 } ## end unless ($piped = open(OUT,...
3323
3324 # Set up broken-pipe handler if necessary.
e22ea7cc
RF
3325 $SIG{PIPE} = \&DB::catch
3326 if $pager =~ /^\|/
3327 && ( "" eq $SIG{PIPE} || "DEFAULT" eq $SIG{PIPE} );
69893cff
RGS
3328
3329 # Save current filehandle, unbuffer out, and put it back.
e22ea7cc
RF
3330 $selected = select(OUT);
3331 $| = 1;
69893cff
RGS
3332
3333 # Don't put it back if pager was a pipe.
e22ea7cc 3334 select($selected), $selected = "" unless $cmd =~ /^\|\|/;
69893cff
RGS
3335
3336 # Trim off the pipe symbols and run the command now.
e22ea7cc
RF
3337 $cmd =~ s/^\|+\s*//;
3338 redo PIPE;
3339 };
69893cff
RGS
3340
3341=head3 END OF COMMAND PARSING
3342
3343Anything left in C<$cmd> at this point is a Perl expression that we want to
3344evaluate. We'll always evaluate in the user's context, and fully qualify
3345any variables we might want to address in the C<DB> package.
3346
3347=cut
3348
3349 # t - turn trace on.
611272bb
PS
3350 $cmd =~ s/^t\s+(\d+)?/\$DB::trace |= 1;\n/ && do {
3351 $trace_to_depth = $1 ? $stack_depth||0 + $1 : 1E9;
3352 };
69893cff
RGS
3353
3354 # s - single-step. Remember the last command was 's'.
e22ea7cc 3355 $cmd =~ s/^s\s/\$DB::single = 1;\n/ && do { $laststep = 's' };
69893cff
RGS
3356
3357 # n - single-step, but not into subs. Remember last command
e22ea7cc
RF
3358 # was 'n'.
3359 $cmd =~ s/^n\s/\$DB::single = 2;\n/ && do { $laststep = 'n' };
69893cff 3360
e22ea7cc 3361 } # PIPE:
69893cff 3362
e22ea7cc 3363 # Make sure the flag that says "the debugger's running" is
69893cff 3364 # still on, to make sure we get control again.
e22ea7cc 3365 $evalarg = "\$^D = \$^D | \$DB::db_stop;\n$cmd";
69893cff
RGS
3366
3367 # Run *our* eval that executes in the caller's context.
e22ea7cc 3368 &eval;
69893cff
RGS
3369
3370 # Turn off the one-time-dump stuff now.
e22ea7cc
RF
3371 if ($onetimeDump) {
3372 $onetimeDump = undef;
69893cff 3373 $onetimedumpDepth = undef;
e22ea7cc
RF
3374 }
3375 elsif ( $term_pid == $$ ) {
c7e68384
IZ
3376 eval { # May run under miniperl, when not available...
3377 STDOUT->flush();
3378 STDERR->flush();
3379 };
e22ea7cc 3380
69893cff 3381 # XXX If this is the master pid, print a newline.
e22ea7cc
RF
3382 print $OUT "\n";
3383 }
3384 } ## end while (($term || &setterm...
69893cff
RGS
3385
3386=head3 POST-COMMAND PROCESSING
3387
3388After each command, we check to see if the command output was piped anywhere.
3389If so, we go through the necessary code to unhook the pipe and go back to
3390our standard filehandles for input and output.
3391
3392=cut
3393
e22ea7cc 3394 continue { # CMD:
69893cff
RGS
3395
3396 # At the end of every command:
e22ea7cc
RF
3397 if ($piped) {
3398
69893cff 3399 # Unhook the pipe mechanism now.
e22ea7cc
RF
3400 if ( $pager =~ /^\|/ ) {
3401
69893cff 3402 # No error from the child.
e22ea7cc 3403 $? = 0;
69893cff 3404
e22ea7cc
RF
3405 # we cannot warn here: the handle is missing --tchrist
3406 close(OUT) || print SAVEOUT "\nCan't close DB::OUT\n";
69893cff 3407
e22ea7cc 3408 # most of the $? crud was coping with broken cshisms
69893cff 3409 # $? is explicitly set to 0, so this never runs.
e22ea7cc 3410 if ($?) {
1f874cb6 3411 print SAVEOUT "Pager '$pager' failed: ";
e22ea7cc
RF
3412 if ( $? == -1 ) {
3413 print SAVEOUT "shell returned -1\n";
3414 }
3415 elsif ( $? >> 8 ) {
3416 print SAVEOUT ( $? & 127 )
3417 ? " (SIG#" . ( $? & 127 ) . ")"
3418 : "", ( $? & 128 ) ? " -- core dumped" : "", "\n";
3419 }
3420 else {
3421 print SAVEOUT "status ", ( $? >> 8 ), "\n";
3422 }
69893cff
RGS
3423 } ## end if ($?)
3424
e22ea7cc 3425 # Reopen filehandle for our output (if we can) and
69893cff 3426 # restore STDOUT (if we can).
e22ea7cc
RF
3427 open( OUT, ">&STDOUT" ) || &warn("Can't restore DB::OUT");
3428 open( STDOUT, ">&SAVEOUT" )
3429 || &warn("Can't restore STDOUT");
69893cff
RGS
3430
3431 # Turn off pipe exception handler if necessary.
e22ea7cc 3432 $SIG{PIPE} = "DEFAULT" if $SIG{PIPE} eq \&DB::catch;
69893cff 3433
e22ea7cc
RF
3434 # Will stop ignoring SIGPIPE if done like nohup(1)
3435 # does SIGINT but Perl doesn't give us a choice.
69893cff 3436 } ## end if ($pager =~ /^\|/)
e22ea7cc
RF
3437 else {
3438
69893cff 3439 # Non-piped "pager". Just restore STDOUT.
e22ea7cc
RF
3440 open( OUT, ">&SAVEOUT" ) || &warn("Can't restore DB::OUT");
3441 }
69893cff
RGS
3442
3443 # Close filehandle pager was using, restore the normal one
3444 # if necessary,
3445 close(SAVEOUT);
e22ea7cc 3446 select($selected), $selected = "" unless $selected eq "";
69893cff
RGS
3447
3448 # No pipes now.
e22ea7cc 3449 $piped = "";
69893cff 3450 } ## end if ($piped)
e22ea7cc 3451 } # CMD:
69893cff
RGS
3452
3453=head3 COMMAND LOOP TERMINATION
3454
3455When commands have finished executing, we come here. If the user closed the
3456input filehandle, we turn on C<$fall_off_end> to emulate a C<q> command. We
3457evaluate any post-prompt items. We restore C<$@>, C<$!>, C<$^E>, C<$,>, C<$/>,
3458C<$\>, and C<$^W>, and return a null list as expected by the Perl interpreter.
3459The interpreter will then execute the next line and then return control to us
3460again.
3461
3462=cut
3463
3464 # No more commands? Quit.
1f874cb6 3465 $fall_off_end = 1 unless defined $cmd; # Emulate 'q' on EOF
69893cff
RGS
3466
3467 # Evaluate post-prompt commands.
e22ea7cc
RF
3468 foreach $evalarg (@$post) {
3469 &eval;
3470 }
3471 } # if ($single || $signal)
69893cff
RGS
3472
3473 # Put the user's globals back where you found them.
e22ea7cc 3474 ( $@, $!, $^E, $,, $/, $\, $^W ) = @saved;
69893cff
RGS
3475 ();
3476} ## end sub DB
3477
3478# The following code may be executed now:
3479# BEGIN {warn 4}
3480
3481=head2 sub
3482
3483C<sub> is called whenever a subroutine call happens in the program being
3484debugged. The variable C<$DB::sub> contains the name of the subroutine
3485being called.
3486
3487The core function of this subroutine is to actually call the sub in the proper
3488context, capturing its output. This of course causes C<DB::DB> to get called
3489again, repeating until the subroutine ends and returns control to C<DB::sub>
3490again. Once control returns, C<DB::sub> figures out whether or not to dump the
3491return value, and returns its captured copy of the return value as its own
3492return value. The value then feeds back into the program being debugged as if
3493C<DB::sub> hadn't been there at all.
3494
3495C<sub> does all the work of printing the subroutine entry and exit messages
3496enabled by setting C<$frame>. It notes what sub the autoloader got called for,
3497and also prints the return value if needed (for the C<r> command and if
3498the 16 bit is set in C<$frame>).
3499
3500It also tracks the subroutine call depth by saving the current setting of
3501C<$single> in the C<@stack> package global; if this exceeds the value in
3502C<$deep>, C<sub> automatically turns on printing of the current depth by
be9a9b1d 3503setting the C<4> bit in C<$single>. In any case, it keeps the current setting
69893cff
RGS
3504of stop/don't stop on entry to subs set as it currently is set.
3505
3506=head3 C<caller()> support
3507
3508If C<caller()> is called from the package C<DB>, it provides some
3509additional data, in the following order:
3510
3511=over 4
3512
3513=item * C<$package>
3514
3515The package name the sub was in
3516
3517=item * C<$filename>
3518
3519The filename it was defined in
3520
3521=item * C<$line>
3522
3523The line number it was defined on
3524
3525=item * C<$subroutine>
3526
be9a9b1d 3527The subroutine name; C<(eval)> if an C<eval>().
69893cff
RGS
3528
3529=item * C<$hasargs>
3530
35311 if it has arguments, 0 if not
3532
3533=item * C<$wantarray>
3534
35351 if array context, 0 if scalar context
3536
3537=item * C<$evaltext>
3538
3539The C<eval>() text, if any (undefined for C<eval BLOCK>)
3540
3541=item * C<$is_require>
3542
3543frame was created by a C<use> or C<require> statement
3544
3545=item * C<$hints>
3546
3547pragma information; subject to change between versions
3548
3549=item * C<$bitmask>
3550
be9a9b1d 3551pragma information; subject to change between versions
69893cff
RGS
3552
3553=item * C<@DB::args>
3554
3555arguments with which the subroutine was invoked
3556
3557=back
3558
3559=cut
d338d6fe 3560
6b24a4b7
SF
3561use vars qw($deep);
3562
3563# We need to fully qualify the name ("DB::sub") to make "use strict;"
3564# happy. -- Shlomi Fish
3565sub DB::sub {
b7bfa855
B
3566 # Do not use a regex in this subroutine -> results in corrupted memory
3567 # See: [perl #66110]
69893cff 3568
2cbb2ee1
RGS
3569 # lock ourselves under threads
3570 lock($DBGR);
3571
69893cff
RGS
3572 # Whether or not the autoloader was running, a scalar to put the
3573 # sub's return value in (if needed), and an array to put the sub's
3574 # return value in (if needed).
e22ea7cc 3575 my ( $al, $ret, @ret ) = "";
b7bfa855 3576 if ($sub eq 'threads::new' && $ENV{PERL5DB_THREADED}) {
2cbb2ee1
RGS
3577 print "creating new thread\n";
3578 }
69893cff 3579
c81c05fc 3580 # If the last ten characters are '::AUTOLOAD', note we've traced
69893cff 3581 # into AUTOLOAD for $sub.
e22ea7cc 3582 if ( length($sub) > 10 && substr( $sub, -10, 10 ) eq '::AUTOLOAD' ) {
6b24a4b7 3583 no strict 'refs';
c81c05fc 3584 $al = " for $$sub" if defined $$sub;
d12a4851 3585 }
69893cff
RGS
3586
3587 # We stack the stack pointer and then increment it to protect us
3588 # from a situation that might unwind a whole bunch of call frames
3589 # at once. Localizing the stack pointer means that it will automatically
3590 # unwind the same amount when multiple stack frames are unwound.
e22ea7cc 3591 local $stack_depth = $stack_depth + 1; # Protect from non-local exits
69893cff
RGS
3592
3593 # Expand @stack.
d12a4851 3594 $#stack = $stack_depth;
69893cff
RGS
3595
3596 # Save current single-step setting.
d12a4851 3597 $stack[-1] = $single;
69893cff 3598
e22ea7cc 3599 # Turn off all flags except single-stepping.
d12a4851 3600 $single &= 1;
69893cff
RGS
3601
3602 # If we've gotten really deeply recursed, turn on the flag that will
3603 # make us stop with the 'deep recursion' message.
d12a4851 3604 $single |= 4 if $stack_depth == $deep;
69893cff
RGS
3605
3606 # If frame messages are on ...
3607 (
3608 $frame & 4 # Extended frame entry message
e22ea7cc
RF
3609 ? (
3610 print_lineinfo( ' ' x ( $stack_depth - 1 ), "in " ),
69893cff 3611
e22ea7cc 3612 # Why -1? But it works! :-(
69893cff
RGS
3613 # Because print_trace will call add 1 to it and then call
3614 # dump_trace; this results in our skipping -1+1 = 0 stack frames
3615 # in dump_trace.
e22ea7cc
RF
3616 print_trace( $LINEINFO, -1, 1, 1, "$sub$al" )
3617 )
3618 : print_lineinfo( ' ' x ( $stack_depth - 1 ), "entering $sub$al\n" )
3619
69893cff 3620 # standard frame entry message
e22ea7cc
RF
3621 )
3622 if $frame;
69893cff 3623
98dc9551 3624 # Determine the sub's return type, and capture appropriately.
d12a4851 3625 if (wantarray) {
e22ea7cc 3626
69893cff
RGS
3627 # Called in array context. call sub and capture output.
3628 # DB::DB will recursively get control again if appropriate; we'll come
3629 # back here when the sub is finished.
6b24a4b7
SF
3630 {
3631 no strict 'refs';
3632 @ret = &$sub;
3633 }
69893cff
RGS
3634
3635 # Pop the single-step value back off the stack.
e22ea7cc 3636 $single |= $stack[ $stack_depth-- ];
69893cff
RGS
3637
3638 # Check for exit trace messages...
e22ea7cc
RF
3639 (
3640 $frame & 4 # Extended exit message
3641 ? (
3642 print_lineinfo( ' ' x $stack_depth, "out " ),
3643 print_trace( $LINEINFO, -1, 1, 1, "$sub$al" )
3644 )
3645 : print_lineinfo( ' ' x $stack_depth, "exited $sub$al\n" )
3646
69893cff 3647 # Standard exit message
e22ea7cc
RF
3648 )
3649 if $frame & 2;
69893cff
RGS
3650
3651 # Print the return info if we need to.
e22ea7cc
RF
3652 if ( $doret eq $stack_depth or $frame & 16 ) {
3653
69893cff 3654 # Turn off output record separator.
e22ea7cc
RF
3655 local $\ = '';
3656 my $fh = ( $doret eq $stack_depth ? $OUT : $LINEINFO );
69893cff
RGS
3657
3658 # Indent if we're printing because of $frame tracing.
e22ea7cc 3659 print $fh ' ' x $stack_depth if $frame & 16;
69893cff
RGS
3660
3661 # Print the return value.
e22ea7cc
RF
3662 print $fh "list context return from $sub:\n";
3663 dumpit( $fh, \@ret );
69893cff
RGS
3664
3665 # And don't print it again.
e22ea7cc 3666 $doret = -2;
69893cff 3667 } ## end if ($doret eq $stack_depth...
e22ea7cc
RF
3668 # And we have to return the return value now.
3669 @ret;
69893cff
RGS
3670 } ## end if (wantarray)
3671
3672 # Scalar context.
3673 else {
584420f0 3674 if ( defined wantarray ) {
6b24a4b7 3675 no strict 'refs';
584420f0
RGS
3676 # Save the value if it's wanted at all.
3677 $ret = &$sub;
3678 }
3679 else {
6b24a4b7 3680 no strict 'refs';
584420f0
RGS
3681 # Void return, explicitly.
3682 &$sub;
3683 undef $ret;
3684 }
69893cff
RGS
3685
3686 # Pop the single-step value off the stack.
e22ea7cc 3687 $single |= $stack[ $stack_depth-- ];
69893cff
RGS
3688
3689 # If we're doing exit messages...
e22ea7cc 3690 (
98dc9551 3691 $frame & 4 # Extended messages
e22ea7cc
RF