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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
c7e68384 513BEGIN {eval 'use IO::Handle'}; # Needed for flush only? breaks under miniperl
9eba6a4e 514
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515BEGIN {
516 require feature;
517 $^V =~ /^v(\d+\.\d+)/;
518 feature->import(":$1");
519}
520
54d04a52 521# Debugger for Perl 5.00x; perl5db.pl patch level:
d24ca0c5 522$VERSION = '1.38';
69893cff 523
e22ea7cc 524$header = "perl5db.pl version $VERSION";
d338d6fe 525
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526=head1 DEBUGGER ROUTINES
527
528=head2 C<DB::eval()>
529
530This function replaces straight C<eval()> inside the debugger; it simplifies
531the process of evaluating code in the user's context.
532
533The code to be evaluated is passed via the package global variable
534C<$DB::evalarg>; this is done to avoid fiddling with the contents of C<@_>.
535
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536Before we do the C<eval()>, we preserve the current settings of C<$trace>,
537C<$single>, C<$^D> and C<$usercontext>. The latter contains the
538preserved values of C<$@>, C<$!>, C<$^E>, C<$,>, C<$/>, C<$\>, C<$^W> and the
539user's current package, grabbed when C<DB::DB> got control. This causes the
540proper context to be used when the eval is actually done. Afterward, we
541restore C<$trace>, C<$single>, and C<$^D>.
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542
543Next we need to handle C<$@> without getting confused. We save C<$@> in a
544local lexical, localize C<$saved[0]> (which is where C<save()> will put
545C<$@>), and then call C<save()> to capture C<$@>, C<$!>, C<$^E>, C<$,>,
546C<$/>, C<$\>, and C<$^W>) and set C<$,>, C<$/>, C<$\>, and C<$^W> to values
547considered sane by the debugger. If there was an C<eval()> error, we print
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548it on the debugger's output. If C<$onetimedump> is defined, we call
549C<dumpit> if it's set to 'dump', or C<methods> if it's set to
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550'methods'. Setting it to something else causes the debugger to do the eval
551but not print the result - handy if you want to do something else with it
552(the "watch expressions" code does this to get the value of the watch
553expression but not show it unless it matters).
554
555In any case, we then return the list of output from C<eval> to the caller,
556and unwinding restores the former version of C<$@> in C<@saved> as well
557(the localization of C<$saved[0]> goes away at the end of this scope).
558
559=head3 Parameters and variables influencing execution of DB::eval()
560
561C<DB::eval> isn't parameterized in the standard way; this is to keep the
562debugger's calls to C<DB::eval()> from mucking with C<@_>, among other things.
563The variables listed below influence C<DB::eval()>'s execution directly.
564
565=over 4
566
567=item C<$evalarg> - the thing to actually be eval'ed
568
be9a9b1d 569=item C<$trace> - Current state of execution tracing
69893cff 570
be9a9b1d 571=item C<$single> - Current state of single-stepping
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572
573=item C<$onetimeDump> - what is to be displayed after the evaluation
574
575=item C<$onetimeDumpDepth> - how deep C<dumpit()> should go when dumping results
576
577=back
578
579The following variables are altered by C<DB::eval()> during its execution. They
580are "stacked" via C<local()>, enabling recursive calls to C<DB::eval()>.
581
582=over 4
583
584=item C<@res> - used to capture output from actual C<eval>.
585
586=item C<$otrace> - saved value of C<$trace>.
587
588=item C<$osingle> - saved value of C<$single>.
589
590=item C<$od> - saved value of C<$^D>.
591
592=item C<$saved[0]> - saved value of C<$@>.
593
594=item $\ - for output of C<$@> if there is an evaluation error.
595
596=back
597
598=head3 The problem of lexicals
599
600The context of C<DB::eval()> presents us with some problems. Obviously,
601we want to be 'sandboxed' away from the debugger's internals when we do
602the eval, but we need some way to control how punctuation variables and
603debugger globals are used.
604
605We can't use local, because the code inside C<DB::eval> can see localized
606variables; and we can't use C<my> either for the same reason. The code
607in this routine compromises and uses C<my>.
608
609After this routine is over, we don't have user code executing in the debugger's
610context, so we can use C<my> freely.
611
612=cut
613
614############################################## Begin lexical danger zone
615
616# 'my' variables used here could leak into (that is, be visible in)
617# the context that the code being evaluated is executing in. This means that
618# the code could modify the debugger's variables.
619#
620# Fiddling with the debugger's context could be Bad. We insulate things as
621# much as we can.
622
c1051fcf 623sub eval {
69893cff 624
c1051fcf 625 # 'my' would make it visible from user code
e22ea7cc 626 # but so does local! --tchrist
69893cff 627 # Remember: this localizes @DB::res, not @main::res.
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628 local @res;
629 {
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630
631 # Try to keep the user code from messing with us. Save these so that
632 # even if the eval'ed code changes them, we can put them back again.
633 # Needed because the user could refer directly to the debugger's
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634 # package globals (and any 'my' variables in this containing scope)
635 # inside the eval(), and we want to try to stay safe.
e22ea7cc 636 local $otrace = $trace;
69893cff
RGS
637 local $osingle = $single;
638 local $od = $^D;
639
640 # Untaint the incoming eval() argument.
641 { ($evalarg) = $evalarg =~ /(.*)/s; }
642
e22ea7cc 643 # $usercontext built in DB::DB near the comment
69893cff
RGS
644 # "set up the context for DB::eval ..."
645 # Evaluate and save any results.
e22ea7cc 646 @res = eval "$usercontext $evalarg;\n"; # '\n' for nice recursive debug
69893cff
RGS
647
648 # Restore those old values.
649 $trace = $otrace;
650 $single = $osingle;
651 $^D = $od;
c1051fcf 652 }
69893cff
RGS
653
654 # Save the current value of $@, and preserve it in the debugger's copy
655 # of the saved precious globals.
c1051fcf 656 my $at = $@;
69893cff
RGS
657
658 # Since we're only saving $@, we only have to localize the array element
659 # that it will be stored in.
e22ea7cc 660 local $saved[0]; # Preserve the old value of $@
c1051fcf 661 eval { &DB::save };
69893cff
RGS
662
663 # Now see whether we need to report an error back to the user.
c1051fcf 664 if ($at) {
69893cff
RGS
665 local $\ = '';
666 print $OUT $at;
667 }
668
669 # Display as required by the caller. $onetimeDump and $onetimedumpDepth
670 # are package globals.
671 elsif ($onetimeDump) {
e22ea7cc
RF
672 if ( $onetimeDump eq 'dump' ) {
673 local $option{dumpDepth} = $onetimedumpDepth
674 if defined $onetimedumpDepth;
675 dumpit( $OUT, \@res );
676 }
677 elsif ( $onetimeDump eq 'methods' ) {
678 methods( $res[0] );
679 }
69893cff 680 } ## end elsif ($onetimeDump)
c1051fcf 681 @res;
69893cff
RGS
682} ## end sub eval
683
684############################################## End lexical danger zone
c1051fcf 685
e22ea7cc
RF
686# After this point it is safe to introduce lexicals.
687# The code being debugged will be executing in its own context, and
69893cff 688# can't see the inside of the debugger.
d338d6fe 689#
e22ea7cc 690# However, one should not overdo it: leave as much control from outside as
69893cff
RGS
691# possible. If you make something a lexical, it's not going to be addressable
692# from outside the debugger even if you know its name.
693
d338d6fe
PP
694# This file is automatically included if you do perl -d.
695# It's probably not useful to include this yourself.
696#
e22ea7cc 697# Before venturing further into these twisty passages, it is
2f7e9187
MS
698# wise to read the perldebguts man page or risk the ire of dragons.
699#
69893cff
RGS
700# (It should be noted that perldebguts will tell you a lot about
701# the underlying mechanics of how the debugger interfaces into the
702# Perl interpreter, but not a lot about the debugger itself. The new
703# comments in this code try to address this problem.)
704
d338d6fe 705# Note that no subroutine call is possible until &DB::sub is defined
36477c24 706# (for subroutines defined outside of the package DB). In fact the same is
d338d6fe 707# true if $deep is not defined.
055fd3a9
GS
708
709# Enhanced by ilya@math.ohio-state.edu (Ilya Zakharevich)
055fd3a9
GS
710
711# modified Perl debugger, to be run from Emacs in perldb-mode
712# Ray Lischner (uunet!mntgfx!lisch) as of 5 Nov 1990
713# Johan Vromans -- upgrade to 4.0 pl 10
714# Ilya Zakharevich -- patches after 5.001 (and some before ;-)
6fae1ad7 715########################################################################
d338d6fe 716
69893cff
RGS
717=head1 DEBUGGER INITIALIZATION
718
719The debugger starts up in phases.
720
721=head2 BASIC SETUP
722
723First, it initializes the environment it wants to run in: turning off
724warnings during its own compilation, defining variables which it will need
725to avoid warnings later, setting itself up to not exit when the program
726terminates, and defaulting to printing return values for the C<r> command.
727
728=cut
729
eda6e075 730# Needed for the statement after exec():
69893cff
RGS
731#
732# This BEGIN block is simply used to switch off warnings during debugger
98dc9551 733# compilation. Probably it would be better practice to fix the warnings,
69893cff 734# but this is how it's done at the moment.
eda6e075 735
e22ea7cc
RF
736BEGIN {
737 $ini_warn = $^W;
738 $^W = 0;
739} # Switch compilation warnings off until another BEGIN.
d12a4851 740
69893cff
RGS
741local ($^W) = 0; # Switch run-time warnings off during init.
742
2cbb2ee1
RGS
743=head2 THREADS SUPPORT
744
745If we are running under a threaded Perl, we require threads and threads::shared
746if the environment variable C<PERL5DB_THREADED> is set, to enable proper
747threaded debugger control. C<-dt> can also be used to set this.
748
749Each new thread will be announced and the debugger prompt will always inform
750you of each new thread created. It will also indicate the thread id in which
751we are currently running within the prompt like this:
752
753 [tid] DB<$i>
754
755Where C<[tid]> is an integer thread id and C<$i> is the familiar debugger
756command prompt. The prompt will show: C<[0]> when running under threads, but
757not actually in a thread. C<[tid]> is consistent with C<gdb> usage.
758
759While running under threads, when you set or delete a breakpoint (etc.), this
760will apply to all threads, not just the currently running one. When you are
761in a currently executing thread, you will stay there until it completes. With
762the current implementation it is not currently possible to hop from one thread
763to another.
764
765The C<e> and C<E> commands are currently fairly minimal - see C<h e> and C<h E>.
766
767Note that threading support was built into the debugger as of Perl version
768C<5.8.6> and debugger version C<1.2.8>.
769
770=cut
771
772BEGIN {
773 # ensure we can share our non-threaded variables or no-op
774 if ($ENV{PERL5DB_THREADED}) {
775 require threads;
776 require threads::shared;
777 import threads::shared qw(share);
778 $DBGR;
779 share(\$DBGR);
780 lock($DBGR);
781 print "Threads support enabled\n";
782 } else {
783 *lock = sub(*) {};
784 *share = sub(*) {};
785 }
786}
787
69893cff
RGS
788# This would probably be better done with "use vars", but that wasn't around
789# when this code was originally written. (Neither was "use strict".) And on
790# the principle of not fiddling with something that was working, this was
791# left alone.
792warn( # Do not ;-)
2cbb2ee1 793 # These variables control the execution of 'dumpvar.pl'.
69893cff
RGS
794 $dumpvar::hashDepth,
795 $dumpvar::arrayDepth,
796 $dumpvar::dumpDBFiles,
797 $dumpvar::dumpPackages,
798 $dumpvar::quoteHighBit,
799 $dumpvar::printUndef,
800 $dumpvar::globPrint,
801 $dumpvar::usageOnly,
802
803 # used to save @ARGV and extract any debugger-related flags.
804 @ARGS,
805
806 # used to control die() reporting in diesignal()
807 $Carp::CarpLevel,
808
809 # used to prevent multiple entries to diesignal()
810 # (if for instance diesignal() itself dies)
811 $panic,
812
813 # used to prevent the debugger from running nonstop
814 # after a restart
815 $second_time,
816 )
817 if 0;
d338d6fe 818
422c59bf 819# without threads, $filename is not defined until DB::DB is called
2cbb2ee1 820foreach my $k (keys (%INC)) {
bc6438f2 821 &share(\$main::{'_<'.$filename}) if defined $filename;
2cbb2ee1
RGS
822};
823
54d04a52 824# Command-line + PERLLIB:
69893cff 825# Save the contents of @INC before they are modified elsewhere.
54d04a52
IZ
826@ini_INC = @INC;
827
69893cff
RGS
828# This was an attempt to clear out the previous values of various
829# trapped errors. Apparently it didn't help. XXX More info needed!
d338d6fe
PP
830# $prevwarn = $prevdie = $prevbus = $prevsegv = ''; # Does not help?!
831
69893cff
RGS
832# We set these variables to safe values. We don't want to blindly turn
833# off warnings, because other packages may still want them.
e22ea7cc
RF
834$trace = $signal = $single = 0; # Uninitialized warning suppression
835 # (local $^W cannot help - other packages!).
69893cff
RGS
836
837# Default to not exiting when program finishes; print the return
838# value when the 'r' command is used to return from a subroutine.
55497cff 839$inhibit_exit = $option{PrintRet} = 1;
d338d6fe 840
bdba49ad
SF
841# Default to 1 so the prompt will display the first line.
842$trace_to_depth = 1;
843
69893cff
RGS
844=head1 OPTION PROCESSING
845
846The debugger's options are actually spread out over the debugger itself and
847C<dumpvar.pl>; some of these are variables to be set, while others are
848subs to be called with a value. To try to make this a little easier to
849manage, the debugger uses a few data structures to define what options
850are legal and how they are to be processed.
851
852First, the C<@options> array defines the I<names> of all the options that
853are to be accepted.
854
855=cut
856
857@options = qw(
5561b870 858 CommandSet HistFile HistSize
e22ea7cc
RF
859 hashDepth arrayDepth dumpDepth
860 DumpDBFiles DumpPackages DumpReused
861 compactDump veryCompact quote
862 HighBit undefPrint globPrint
863 PrintRet UsageOnly frame
864 AutoTrace TTY noTTY
865 ReadLine NonStop LineInfo
866 maxTraceLen recallCommand ShellBang
867 pager tkRunning ornaments
868 signalLevel warnLevel dieLevel
869 inhibit_exit ImmediateStop bareStringify
870 CreateTTY RemotePort windowSize
584420f0 871 DollarCaretP
e22ea7cc 872);
d12a4851 873
584420f0 874@RememberOnROptions = qw(DollarCaretP);
d12a4851 875
69893cff
RGS
876=pod
877
878Second, C<optionVars> lists the variables that each option uses to save its
879state.
880
881=cut
882
883%optionVars = (
e22ea7cc
RF
884 hashDepth => \$dumpvar::hashDepth,
885 arrayDepth => \$dumpvar::arrayDepth,
886 CommandSet => \$CommandSet,
887 DumpDBFiles => \$dumpvar::dumpDBFiles,
888 DumpPackages => \$dumpvar::dumpPackages,
889 DumpReused => \$dumpvar::dumpReused,
890 HighBit => \$dumpvar::quoteHighBit,
891 undefPrint => \$dumpvar::printUndef,
892 globPrint => \$dumpvar::globPrint,
893 UsageOnly => \$dumpvar::usageOnly,
894 CreateTTY => \$CreateTTY,
895 bareStringify => \$dumpvar::bareStringify,
896 frame => \$frame,
897 AutoTrace => \$trace,
898 inhibit_exit => \$inhibit_exit,
899 maxTraceLen => \$maxtrace,
900 ImmediateStop => \$ImmediateStop,
901 RemotePort => \$remoteport,
902 windowSize => \$window,
5561b870
AK
903 HistFile => \$histfile,
904 HistSize => \$histsize,
69893cff
RGS
905);
906
907=pod
908
909Third, C<%optionAction> defines the subroutine to be called to process each
910option.
911
912=cut
913
914%optionAction = (
915 compactDump => \&dumpvar::compactDump,
916 veryCompact => \&dumpvar::veryCompact,
917 quote => \&dumpvar::quote,
918 TTY => \&TTY,
919 noTTY => \&noTTY,
920 ReadLine => \&ReadLine,
921 NonStop => \&NonStop,
922 LineInfo => \&LineInfo,
923 recallCommand => \&recallCommand,
924 ShellBang => \&shellBang,
925 pager => \&pager,
926 signalLevel => \&signalLevel,
927 warnLevel => \&warnLevel,
928 dieLevel => \&dieLevel,
929 tkRunning => \&tkRunning,
930 ornaments => \&ornaments,
931 RemotePort => \&RemotePort,
932 DollarCaretP => \&DollarCaretP,
d12a4851
JH
933);
934
69893cff
RGS
935=pod
936
937Last, the C<%optionRequire> notes modules that must be C<require>d if an
938option is used.
939
940=cut
d338d6fe 941
69893cff
RGS
942# Note that this list is not complete: several options not listed here
943# actually require that dumpvar.pl be loaded for them to work, but are
944# not in the table. A subsequent patch will correct this problem; for
945# the moment, we're just recommenting, and we are NOT going to change
946# function.
eda6e075 947%optionRequire = (
69893cff
RGS
948 compactDump => 'dumpvar.pl',
949 veryCompact => 'dumpvar.pl',
950 quote => 'dumpvar.pl',
e22ea7cc 951);
69893cff
RGS
952
953=pod
954
955There are a number of initialization-related variables which can be set
956by putting code to set them in a BEGIN block in the C<PERL5DB> environment
957variable. These are:
958
959=over 4
960
961=item C<$rl> - readline control XXX needs more explanation
962
963=item C<$warnLevel> - whether or not debugger takes over warning handling
964
965=item C<$dieLevel> - whether or not debugger takes over die handling
966
967=item C<$signalLevel> - whether or not debugger takes over signal handling
968
969=item C<$pre> - preprompt actions (array reference)
970
971=item C<$post> - postprompt actions (array reference)
972
973=item C<$pretype>
974
975=item C<$CreateTTY> - whether or not to create a new TTY for this debugger
976
977=item C<$CommandSet> - which command set to use (defaults to new, documented set)
978
979=back
980
981=cut
d338d6fe
PP
982
983# These guys may be defined in $ENV{PERL5DB} :
69893cff
RGS
984$rl = 1 unless defined $rl;
985$warnLevel = 1 unless defined $warnLevel;
986$dieLevel = 1 unless defined $dieLevel;
987$signalLevel = 1 unless defined $signalLevel;
988$pre = [] unless defined $pre;
989$post = [] unless defined $post;
990$pretype = [] unless defined $pretype;
991$CreateTTY = 3 unless defined $CreateTTY;
992$CommandSet = '580' unless defined $CommandSet;
993
2cbb2ee1
RGS
994share($rl);
995share($warnLevel);
996share($dieLevel);
997share($signalLevel);
998share($pre);
999share($post);
1000share($pretype);
1001share($rl);
1002share($CreateTTY);
1003share($CommandSet);
1004
69893cff
RGS
1005=pod
1006
1007The default C<die>, C<warn>, and C<signal> handlers are set up.
1008
1009=cut
055fd3a9 1010
d338d6fe
PP
1011warnLevel($warnLevel);
1012dieLevel($dieLevel);
1013signalLevel($signalLevel);
055fd3a9 1014
69893cff
RGS
1015=pod
1016
1017The pager to be used is needed next. We try to get it from the
5561b870 1018environment first. If it's not defined there, we try to find it in
69893cff
RGS
1019the Perl C<Config.pm>. If it's not there, we default to C<more>. We
1020then call the C<pager()> function to save the pager name.
1021
1022=cut
1023
1024# This routine makes sure $pager is set up so that '|' can use it.
4865a36d 1025pager(
e22ea7cc 1026
69893cff 1027 # If PAGER is defined in the environment, use it.
e22ea7cc
RF
1028 defined $ENV{PAGER}
1029 ? $ENV{PAGER}
69893cff
RGS
1030
1031 # If not, see if Config.pm defines it.
e22ea7cc
RF
1032 : eval { require Config }
1033 && defined $Config::Config{pager}
1034 ? $Config::Config{pager}
69893cff
RGS
1035
1036 # If not, fall back to 'more'.
e22ea7cc
RF
1037 : 'more'
1038 )
1039 unless defined $pager;
69893cff
RGS
1040
1041=pod
1042
1043We set up the command to be used to access the man pages, the command
be9a9b1d
AT
1044recall character (C<!> unless otherwise defined) and the shell escape
1045character (C<!> unless otherwise defined). Yes, these do conflict, and
69893cff
RGS
1046neither works in the debugger at the moment.
1047
1048=cut
1049
055fd3a9 1050setman();
69893cff
RGS
1051
1052# Set up defaults for command recall and shell escape (note:
1053# these currently don't work in linemode debugging).
d338d6fe 1054&recallCommand("!") unless defined $prc;
69893cff
RGS
1055&shellBang("!") unless defined $psh;
1056
1057=pod
1058
1059We then set up the gigantic string containing the debugger help.
1060We also set the limit on the number of arguments we'll display during a
1061trace.
1062
1063=cut
1064
04e43a21 1065sethelp();
69893cff
RGS
1066
1067# If we didn't get a default for the length of eval/stack trace args,
1068# set it here.
1d06cb2d 1069$maxtrace = 400 unless defined $maxtrace;
69893cff
RGS
1070
1071=head2 SETTING UP THE DEBUGGER GREETING
1072
be9a9b1d 1073The debugger I<greeting> helps to inform the user how many debuggers are
69893cff
RGS
1074running, and whether the current debugger is the primary or a child.
1075
1076If we are the primary, we just hang onto our pid so we'll have it when
1077or if we start a child debugger. If we are a child, we'll set things up
1078so we'll have a unique greeting and so the parent will give us our own
1079TTY later.
1080
1081We save the current contents of the C<PERLDB_PIDS> environment variable
1082because we mess around with it. We'll also need to hang onto it because
1083we'll need it if we restart.
1084
1085Child debuggers make a label out of the current PID structure recorded in
1086PERLDB_PIDS plus the new PID. They also mark themselves as not having a TTY
1087yet so the parent will give them one later via C<resetterm()>.
1088
1089=cut
1090
e22ea7cc 1091# Save the current contents of the environment; we're about to
69893cff 1092# much with it. We'll need this if we have to restart.
f1583d8f 1093$ini_pids = $ENV{PERLDB_PIDS};
69893cff 1094
e22ea7cc
RF
1095if ( defined $ENV{PERLDB_PIDS} ) {
1096
69893cff 1097 # We're a child. Make us a label out of the current PID structure
e22ea7cc 1098 # recorded in PERLDB_PIDS plus our (new) PID. Mark us as not having
69893cff 1099 # a term yet so the parent will give us one later via resetterm().
55f4245e
JM
1100
1101 my $env_pids = $ENV{PERLDB_PIDS};
1102 $pids = "[$env_pids]";
1103
1104 # Unless we are on OpenVMS, all programs under the DCL shell run under
1105 # the same PID.
1106
1107 if (($^O eq 'VMS') && ($env_pids =~ /\b$$\b/)) {
1108 $term_pid = $$;
1109 }
1110 else {
1111 $ENV{PERLDB_PIDS} .= "->$$";
1112 $term_pid = -1;
1113 }
1114
69893cff
RGS
1115} ## end if (defined $ENV{PERLDB_PIDS...
1116else {
e22ea7cc
RF
1117
1118 # We're the parent PID. Initialize PERLDB_PID in case we end up with a
69893cff
RGS
1119 # child debugger, and mark us as the parent, so we'll know to set up
1120 # more TTY's is we have to.
1121 $ENV{PERLDB_PIDS} = "$$";
619a0444 1122 $pids = "[pid=$$]";
e22ea7cc 1123 $term_pid = $$;
f1583d8f 1124}
69893cff 1125
f1583d8f 1126$pidprompt = '';
69893cff
RGS
1127
1128# Sets up $emacs as a synonym for $slave_editor.
1129*emacs = $slave_editor if $slave_editor; # May be used in afterinit()...
1130
1131=head2 READING THE RC FILE
1132
1133The debugger will read a file of initialization options if supplied. If
1134running interactively, this is C<.perldb>; if not, it's C<perldb.ini>.
1135
1136=cut
1137
1138# As noted, this test really doesn't check accurately that the debugger
1139# is running at a terminal or not.
d338d6fe 1140
98274836
JM
1141my $dev_tty = '/dev/tty';
1142 $dev_tty = 'TT:' if ($^O eq 'VMS');
1143if ( -e $dev_tty ) { # this is the wrong metric!
e22ea7cc
RF
1144 $rcfile = ".perldb";
1145}
69893cff
RGS
1146else {
1147 $rcfile = "perldb.ini";
d338d6fe
PP
1148}
1149
69893cff
RGS
1150=pod
1151
1152The debugger does a safety test of the file to be read. It must be owned
1153either by the current user or root, and must only be writable by the owner.
1154
1155=cut
1156
1157# This wraps a safety test around "do" to read and evaluate the init file.
1158#
055fd3a9
GS
1159# This isn't really safe, because there's a race
1160# between checking and opening. The solution is to
1161# open and fstat the handle, but then you have to read and
1162# eval the contents. But then the silly thing gets
69893cff
RGS
1163# your lexical scope, which is unfortunate at best.
1164sub safe_do {
055fd3a9
GS
1165 my $file = shift;
1166
1167 # Just exactly what part of the word "CORE::" don't you understand?
69893cff
RGS
1168 local $SIG{__WARN__};
1169 local $SIG{__DIE__};
055fd3a9 1170
e22ea7cc 1171 unless ( is_safe_file($file) ) {
69893cff 1172 CORE::warn <<EO_GRIPE;
055fd3a9
GS
1173perldb: Must not source insecure rcfile $file.
1174 You or the superuser must be the owner, and it must not
69893cff 1175 be writable by anyone but its owner.
055fd3a9 1176EO_GRIPE
69893cff
RGS
1177 return;
1178 } ## end unless (is_safe_file($file...
055fd3a9
GS
1179
1180 do $file;
1181 CORE::warn("perldb: couldn't parse $file: $@") if $@;
69893cff 1182} ## end sub safe_do
055fd3a9 1183
69893cff
RGS
1184# This is the safety test itself.
1185#
055fd3a9
GS
1186# Verifies that owner is either real user or superuser and that no
1187# one but owner may write to it. This function is of limited use
1188# when called on a path instead of upon a handle, because there are
1189# no guarantees that filename (by dirent) whose file (by ino) is
e22ea7cc 1190# eventually accessed is the same as the one tested.
055fd3a9
GS
1191# Assumes that the file's existence is not in doubt.
1192sub is_safe_file {
1193 my $path = shift;
69893cff 1194 stat($path) || return; # mysteriously vaporized
e22ea7cc 1195 my ( $dev, $ino, $mode, $nlink, $uid, $gid ) = stat(_);
055fd3a9
GS
1196
1197 return 0 if $uid != 0 && $uid != $<;
1198 return 0 if $mode & 022;
1199 return 1;
69893cff 1200} ## end sub is_safe_file
055fd3a9 1201
69893cff 1202# If the rcfile (whichever one we decided was the right one to read)
e22ea7cc
RF
1203# exists, we safely do it.
1204if ( -f $rcfile ) {
055fd3a9 1205 safe_do("./$rcfile");
69893cff 1206}
e22ea7cc 1207
69893cff 1208# If there isn't one here, try the user's home directory.
e22ea7cc 1209elsif ( defined $ENV{HOME} && -f "$ENV{HOME}/$rcfile" ) {
055fd3a9
GS
1210 safe_do("$ENV{HOME}/$rcfile");
1211}
e22ea7cc 1212
69893cff 1213# Else try the login directory.
e22ea7cc 1214elsif ( defined $ENV{LOGDIR} && -f "$ENV{LOGDIR}/$rcfile" ) {
055fd3a9 1215 safe_do("$ENV{LOGDIR}/$rcfile");
d338d6fe
PP
1216}
1217
69893cff 1218# If the PERLDB_OPTS variable has options in it, parse those out next.
e22ea7cc
RF
1219if ( defined $ENV{PERLDB_OPTS} ) {
1220 parse_options( $ENV{PERLDB_OPTS} );
d338d6fe
PP
1221}
1222
69893cff
RGS
1223=pod
1224
1225The last thing we do during initialization is determine which subroutine is
1226to be used to obtain a new terminal when a new debugger is started. Right now,
b0b54b5e 1227the debugger only handles TCP sockets, X11, OS/2, amd Mac OS X
11653f7f 1228(darwin).
69893cff
RGS
1229
1230=cut
1231
1232# Set up the get_fork_TTY subroutine to be aliased to the proper routine.
1233# Works if you're running an xterm or xterm-like window, or you're on
6fae1ad7
RF
1234# OS/2, or on Mac OS X. This may need some expansion.
1235
1236if (not defined &get_fork_TTY) # only if no routine exists
69893cff 1237{
11653f7f
JJ
1238 if ( defined $remoteport ) {
1239 # Expect an inetd-like server
1240 *get_fork_TTY = \&socket_get_fork_TTY; # to listen to us
1241 }
1242 elsif (defined $ENV{TERM} # If we know what kind
6fae1ad7
RF
1243 # of terminal this is,
1244 and $ENV{TERM} eq 'xterm' # and it's an xterm,
1245 and defined $ENV{DISPLAY} # and what display it's on,
1246 )
1247 {
1248 *get_fork_TTY = \&xterm_get_fork_TTY; # use the xterm version
1249 }
1250 elsif ( $^O eq 'os2' ) { # If this is OS/2,
1251 *get_fork_TTY = \&os2_get_fork_TTY; # use the OS/2 version
1252 }
1253 elsif ( $^O eq 'darwin' # If this is Mac OS X
1254 and defined $ENV{TERM_PROGRAM} # and we're running inside
1255 and $ENV{TERM_PROGRAM}
1256 eq 'Apple_Terminal' # Terminal.app
1257 )
1258 {
1259 *get_fork_TTY = \&macosx_get_fork_TTY; # use the Mac OS X version
1260 }
69893cff 1261} ## end if (not defined &get_fork_TTY...
e22ea7cc 1262
dbb46cec
DQ
1263# untaint $^O, which may have been tainted by the last statement.
1264# see bug [perl #24674]
e22ea7cc
RF
1265$^O =~ m/^(.*)\z/;
1266$^O = $1;
f1583d8f 1267
d12a4851 1268# Here begin the unreadable code. It needs fixing.
055fd3a9 1269
69893cff
RGS
1270=head2 RESTART PROCESSING
1271
1272This section handles the restart command. When the C<R> command is invoked, it
1273tries to capture all of the state it can into environment variables, and
1274then sets C<PERLDB_RESTART>. When we start executing again, we check to see
1275if C<PERLDB_RESTART> is there; if so, we reload all the information that
1276the R command stuffed into the environment variables.
1277
1278 PERLDB_RESTART - flag only, contains no restart data itself.
1279 PERLDB_HIST - command history, if it's available
1280 PERLDB_ON_LOAD - breakpoints set by the rc file
1281 PERLDB_POSTPONE - subs that have been loaded/not executed, and have actions
1282 PERLDB_VISITED - files that had breakpoints
1283 PERLDB_FILE_... - breakpoints for a file
1284 PERLDB_OPT - active options
1285 PERLDB_INC - the original @INC
1286 PERLDB_PRETYPE - preprompt debugger actions
1287 PERLDB_PRE - preprompt Perl code
1288 PERLDB_POST - post-prompt Perl code
1289 PERLDB_TYPEAHEAD - typeahead captured by readline()
1290
1291We chug through all these variables and plug the values saved in them
1292back into the appropriate spots in the debugger.
1293
1294=cut
1295
e22ea7cc
RF
1296if ( exists $ENV{PERLDB_RESTART} ) {
1297
69893cff 1298 # We're restarting, so we don't need the flag that says to restart anymore.
e22ea7cc
RF
1299 delete $ENV{PERLDB_RESTART};
1300
1301 # $restart = 1;
1302 @hist = get_list('PERLDB_HIST');
1303 %break_on_load = get_list("PERLDB_ON_LOAD");
1304 %postponed = get_list("PERLDB_POSTPONE");
69893cff 1305
2cbb2ee1
RGS
1306 share(@hist);
1307 share(@truehist);
1308 share(%break_on_load);
1309 share(%postponed);
1310
69893cff 1311 # restore breakpoints/actions
e22ea7cc 1312 my @had_breakpoints = get_list("PERLDB_VISITED");
bdba49ad
SF
1313 for my $file_idx ( 0 .. $#had_breakpoints ) {
1314 my $filename = $had_breakpoints[$file_idx];
1315 my %pf = get_list("PERLDB_FILE_$file_idx");
1316 $postponed_file{ $filename } = \%pf if %pf;
1317 my @lines = sort {$a <=> $b} keys(%pf);
1318 my @enabled_statuses = get_list("PERLDB_FILE_ENABLED_$file_idx");
1319 for my $line_idx (0 .. $#lines) {
1320 _set_breakpoint_enabled_status(
1321 $filename,
1322 $lines[$line_idx],
1323 ($enabled_statuses[$line_idx] ? 1 : ''),
1324 );
1325 }
e22ea7cc 1326 }
69893cff
RGS
1327
1328 # restore options
e22ea7cc
RF
1329 my %opt = get_list("PERLDB_OPT");
1330 my ( $opt, $val );
1331 while ( ( $opt, $val ) = each %opt ) {
1332 $val =~ s/[\\\']/\\$1/g;
1333 parse_options("$opt'$val'");
1334 }
69893cff
RGS
1335
1336 # restore original @INC
e22ea7cc
RF
1337 @INC = get_list("PERLDB_INC");
1338 @ini_INC = @INC;
1339
1340 # return pre/postprompt actions and typeahead buffer
1341 $pretype = [ get_list("PERLDB_PRETYPE") ];
1342 $pre = [ get_list("PERLDB_PRE") ];
1343 $post = [ get_list("PERLDB_POST") ];
1344 @typeahead = get_list( "PERLDB_TYPEAHEAD", @typeahead );
69893cff
RGS
1345} ## end if (exists $ENV{PERLDB_RESTART...
1346
1347=head2 SETTING UP THE TERMINAL
1348
1349Now, we'll decide how the debugger is going to interact with the user.
1350If there's no TTY, we set the debugger to run non-stop; there's not going
1351to be anyone there to enter commands.
1352
1353=cut
54d04a52 1354
d338d6fe 1355if ($notty) {
69893cff 1356 $runnonstop = 1;
2cbb2ee1 1357 share($runnonstop);
69893cff 1358}
d12a4851 1359
69893cff
RGS
1360=pod
1361
1362If there is a TTY, we have to determine who it belongs to before we can
1363proceed. If this is a slave editor or graphical debugger (denoted by
1364the first command-line switch being '-emacs'), we shift this off and
1365set C<$rl> to 0 (XXX ostensibly to do straight reads).
1366
1367=cut
1368
1369else {
e22ea7cc 1370
69893cff
RGS
1371 # Is Perl being run from a slave editor or graphical debugger?
1372 # If so, don't use readline, and set $slave_editor = 1.
e22ea7cc
RF
1373 $slave_editor =
1374 ( ( defined $main::ARGV[0] ) and ( $main::ARGV[0] eq '-emacs' ) );
1375 $rl = 0, shift(@main::ARGV) if $slave_editor;
1376
1377 #require Term::ReadLine;
d12a4851 1378
69893cff
RGS
1379=pod
1380
1381We then determine what the console should be on various systems:
1382
1383=over 4
1384
1385=item * Cygwin - We use C<stdin> instead of a separate device.
1386
1387=cut
1388
e22ea7cc
RF
1389 if ( $^O eq 'cygwin' ) {
1390
69893cff
RGS
1391 # /dev/tty is binary. use stdin for textmode
1392 undef $console;
1393 }
1394
1395=item * Unix - use C</dev/tty>.
1396
1397=cut
1398
e22ea7cc 1399 elsif ( -e "/dev/tty" ) {
69893cff
RGS
1400 $console = "/dev/tty";
1401 }
1402
1403=item * Windows or MSDOS - use C<con>.
1404
1405=cut
1406
e22ea7cc 1407 elsif ( $^O eq 'dos' or -e "con" or $^O eq 'MSWin32' ) {
69893cff
RGS
1408 $console = "con";
1409 }
1410
69893cff
RGS
1411=item * VMS - use C<sys$command>.
1412
1413=cut
1414
1415 else {
e22ea7cc 1416
69893cff
RGS
1417 # everything else is ...
1418 $console = "sys\$command";
d12a4851 1419 }
69893cff
RGS
1420
1421=pod
1422
1423=back
1424
1425Several other systems don't use a specific console. We C<undef $console>
1426for those (Windows using a slave editor/graphical debugger, NetWare, OS/2
1427with a slave editor, Epoc).
1428
1429=cut
d12a4851 1430
e22ea7cc
RF
1431 if ( ( $^O eq 'MSWin32' ) and ( $slave_editor or defined $ENV{EMACS} ) ) {
1432
69893cff 1433 # /dev/tty is binary. use stdin for textmode
e22ea7cc
RF
1434 $console = undef;
1435 }
1436
1437 if ( $^O eq 'NetWare' ) {
d12a4851 1438
69893cff
RGS
1439 # /dev/tty is binary. use stdin for textmode
1440 $console = undef;
1441 }
d12a4851 1442
69893cff
RGS
1443 # In OS/2, we need to use STDIN to get textmode too, even though
1444 # it pretty much looks like Unix otherwise.
e22ea7cc
RF
1445 if ( defined $ENV{OS2_SHELL} and ( $slave_editor or $ENV{WINDOWID} ) )
1446 { # In OS/2
1447 $console = undef;
1448 }
1449
1450 # EPOC also falls into the 'got to use STDIN' camp.
1451 if ( $^O eq 'epoc' ) {
1452 $console = undef;
1453 }
d12a4851 1454
69893cff
RGS
1455=pod
1456
1457If there is a TTY hanging around from a parent, we use that as the console.
1458
1459=cut
1460
e22ea7cc 1461 $console = $tty if defined $tty;
d12a4851 1462
69893cff
RGS
1463=head2 SOCKET HANDLING
1464
1465The debugger is capable of opening a socket and carrying out a debugging
1466session over the socket.
1467
1468If C<RemotePort> was defined in the options, the debugger assumes that it
1469should try to start a debugging session on that port. It builds the socket
1470and then tries to connect the input and output filehandles to it.
1471
1472=cut
1473
1474 # Handle socket stuff.
e22ea7cc
RF
1475
1476 if ( defined $remoteport ) {
1477
69893cff
RGS
1478 # If RemotePort was defined in the options, connect input and output
1479 # to the socket.
11653f7f 1480 $IN = $OUT = connect_remoteport();
69893cff
RGS
1481 } ## end if (defined $remoteport)
1482
1483=pod
1484
1485If no C<RemotePort> was defined, and we want to create a TTY on startup,
1486this is probably a situation where multiple debuggers are running (for example,
1487a backticked command that starts up another debugger). We create a new IN and
1488OUT filehandle, and do the necessary mojo to create a new TTY if we know how
1489and if we can.
1490
1491=cut
1492
1493 # Non-socket.
1494 else {
e22ea7cc 1495
69893cff
RGS
1496 # Two debuggers running (probably a system or a backtick that invokes
1497 # the debugger itself under the running one). create a new IN and OUT
e22ea7cc 1498 # filehandle, and do the necessary mojo to create a new tty if we
69893cff 1499 # know how, and we can.
e22ea7cc
RF
1500 create_IN_OUT(4) if $CreateTTY & 4;
1501 if ($console) {
1502
69893cff 1503 # If we have a console, check to see if there are separate ins and
cd1191f1 1504 # outs to open. (They are assumed identical if not.)
69893cff 1505
e22ea7cc
RF
1506 my ( $i, $o ) = split /,/, $console;
1507 $o = $i unless defined $o;
69893cff 1508
69893cff 1509 # read/write on in, or just read, or read on STDIN.
e22ea7cc
RF
1510 open( IN, "+<$i" )
1511 || open( IN, "<$i" )
1512 || open( IN, "<&STDIN" );
1513
69893cff
RGS
1514 # read/write/create/clobber out, or write/create/clobber out,
1515 # or merge with STDERR, or merge with STDOUT.
e22ea7cc
RF
1516 open( OUT, "+>$o" )
1517 || open( OUT, ">$o" )
1518 || open( OUT, ">&STDERR" )
1519 || open( OUT, ">&STDOUT" ); # so we don't dongle stdout
1520
1521 } ## end if ($console)
1522 elsif ( not defined $console ) {
1523
1524 # No console. Open STDIN.
1525 open( IN, "<&STDIN" );
1526
1527 # merge with STDERR, or with STDOUT.
1528 open( OUT, ">&STDERR" )
1529 || open( OUT, ">&STDOUT" ); # so we don't dongle stdout
1530 $console = 'STDIN/OUT';
69893cff
RGS
1531 } ## end elsif (not defined $console)
1532
1533 # Keep copies of the filehandles so that when the pager runs, it
1534 # can close standard input without clobbering ours.
e22ea7cc
RF
1535 $IN = \*IN, $OUT = \*OUT if $console or not defined $console;
1536 } ## end elsif (from if(defined $remoteport))
1537
1538 # Unbuffer DB::OUT. We need to see responses right away.
1539 my $previous = select($OUT);
1540 $| = 1; # for DB::OUT
1541 select($previous);
1542
1543 # Line info goes to debugger output unless pointed elsewhere.
1544 # Pointing elsewhere makes it possible for slave editors to
1545 # keep track of file and position. We have both a filehandle
1546 # and a I/O description to keep track of.
1547 $LINEINFO = $OUT unless defined $LINEINFO;
1548 $lineinfo = $console unless defined $lineinfo;
2cbb2ee1
RGS
1549 # share($LINEINFO); # <- unable to share globs
1550 share($lineinfo); #
e22ea7cc 1551
69893cff
RGS
1552=pod
1553
1554To finish initialization, we show the debugger greeting,
1555and then call the C<afterinit()> subroutine if there is one.
1556
1557=cut
d12a4851 1558
e22ea7cc
RF
1559 # Show the debugger greeting.
1560 $header =~ s/.Header: ([^,]+),v(\s+\S+\s+\S+).*$/$1$2/;
1561 unless ($runnonstop) {
1562 local $\ = '';
1563 local $, = '';
1564 if ( $term_pid eq '-1' ) {
1565 print $OUT "\nDaughter DB session started...\n";
1566 }
1567 else {
1568 print $OUT "\nLoading DB routines from $header\n";
1569 print $OUT (
1570 "Editor support ",
1571 $slave_editor ? "enabled" : "available", ".\n"
1572 );
1573 print $OUT
1f874cb6 1574"\nEnter h or 'h h' for help, or '$doccmd perldebug' for more help.\n\n";
69893cff
RGS
1575 } ## end else [ if ($term_pid eq '-1')
1576 } ## end unless ($runnonstop)
1577} ## end else [ if ($notty)
1578
1579# XXX This looks like a bug to me.
1580# Why copy to @ARGS and then futz with @args?
d338d6fe
PP
1581@ARGS = @ARGV;
1582for (@args) {
69893cff
RGS
1583 # Make sure backslashes before single quotes are stripped out, and
1584 # keep args unless they are numeric (XXX why?)
e22ea7cc
RF
1585 # s/\'/\\\'/g; # removed while not justified understandably
1586 # s/(.*)/'$1'/ unless /^-?[\d.]+$/; # ditto
d338d6fe
PP
1587}
1588
e22ea7cc 1589# If there was an afterinit() sub defined, call it. It will get
69893cff 1590# executed in our scope, so it can fiddle with debugger globals.
e22ea7cc 1591if ( defined &afterinit ) { # May be defined in $rcfile
69893cff 1592 &afterinit();
d338d6fe 1593}
e22ea7cc 1594
69893cff 1595# Inform us about "Stack dump during die enabled ..." in dieLevel().
43aed9ee
IZ
1596$I_m_init = 1;
1597
d338d6fe
PP
1598############################################################ Subroutines
1599
69893cff
RGS
1600=head1 SUBROUTINES
1601
1602=head2 DB
1603
1604This gigantic subroutine is the heart of the debugger. Called before every
1605statement, its job is to determine if a breakpoint has been reached, and
1606stop if so; read commands from the user, parse them, and execute
b468dcb6 1607them, and then send execution off to the next statement.
69893cff
RGS
1608
1609Note that the order in which the commands are processed is very important;
1610some commands earlier in the loop will actually alter the C<$cmd> variable
be9a9b1d 1611to create other commands to be executed later. This is all highly I<optimized>
69893cff
RGS
1612but can be confusing. Check the comments for each C<$cmd ... && do {}> to
1613see what's happening in any given command.
1614
1615=cut
1616
d338d6fe 1617sub DB {
69893cff 1618
2cbb2ee1
RGS
1619 # lock the debugger and get the thread id for the prompt
1620 lock($DBGR);
1621 my $tid;
1622 if ($ENV{PERL5DB_THREADED}) {
878090d5 1623 $tid = eval { "[".threads->tid."]" };
2cbb2ee1
RGS
1624 }
1625
69893cff 1626 # Check for whether we should be running continuously or not.
36477c24 1627 # _After_ the perl program is compiled, $single is set to 1:
e22ea7cc
RF
1628 if ( $single and not $second_time++ ) {
1629
69893cff 1630 # Options say run non-stop. Run until we get an interrupt.
e22ea7cc
RF
1631 if ($runnonstop) { # Disable until signal
1632 # If there's any call stack in place, turn off single
1633 # stepping into subs throughout the stack.
1634 for ( $i = 0 ; $i <= $stack_depth ; ) {
1635 $stack[ $i++ ] &= ~1;
1636 }
1637
69893cff 1638 # And we are now no longer in single-step mode.
e22ea7cc 1639 $single = 0;
69893cff
RGS
1640
1641 # If we simply returned at this point, we wouldn't get
1642 # the trace info. Fall on through.
e22ea7cc 1643 # return;
69893cff
RGS
1644 } ## end if ($runnonstop)
1645
e22ea7cc
RF
1646 elsif ($ImmediateStop) {
1647
1648 # We are supposed to stop here; XXX probably a break.
1649 $ImmediateStop = 0; # We've processed it; turn it off
1650 $signal = 1; # Simulate an interrupt to force
1651 # us into the command loop
69893cff
RGS
1652 }
1653 } ## end if ($single and not $second_time...
1654
1655 # If we're in single-step mode, or an interrupt (real or fake)
1656 # has occurred, turn off non-stop mode.
1657 $runnonstop = 0 if $single or $signal;
1658
1659 # Preserve current values of $@, $!, $^E, $,, $/, $\, $^W.
1660 # The code being debugged may have altered them.
d338d6fe 1661 &save;
69893cff
RGS
1662
1663 # Since DB::DB gets called after every line, we can use caller() to
1664 # figure out where we last were executing. Sneaky, eh? This works because
e22ea7cc 1665 # caller is returning all the extra information when called from the
69893cff 1666 # debugger.
e22ea7cc 1667 local ( $package, $filename, $line ) = caller;
471505cc 1668 local $filename_ini = $filename;
69893cff
RGS
1669
1670 # set up the context for DB::eval, so it can properly execute
1671 # code on behalf of the user. We add the package in so that the
1672 # code is eval'ed in the proper package (not in the debugger!).
1673 local $usercontext =
e22ea7cc 1674 '($@, $!, $^E, $,, $/, $\, $^W) = @saved;' . "package $package;";
69893cff
RGS
1675
1676 # Create an alias to the active file magical array to simplify
1677 # the code here.
e22ea7cc 1678 local (*dbline) = $main::{ '_<' . $filename };
aa057b67 1679
69893cff 1680 # Last line in the program.
471505cc 1681 local $max = $#dbline;
69893cff
RGS
1682
1683 # if we have something here, see if we should break.
e22ea7cc 1684 if ( $dbline{$line}
e09195af 1685 && _is_breakpoint_enabled($filename, $line)
e22ea7cc
RF
1686 && ( ( $stop, $action ) = split( /\0/, $dbline{$line} ) ) )
1687 {
1688
69893cff 1689 # Stop if the stop criterion says to just stop.
e22ea7cc 1690 if ( $stop eq '1' ) {
69893cff
RGS
1691 $signal |= 1;
1692 }
e22ea7cc 1693
69893cff
RGS
1694 # It's a conditional stop; eval it in the user's context and
1695 # see if we should stop. If so, remove the one-time sigil.
1696 elsif ($stop) {
e22ea7cc 1697 $evalarg = "\$DB::signal |= 1 if do {$stop}";
69893cff 1698 &eval;
5d5d9ea3
SF
1699 # If the breakpoint is temporary, then delete its enabled status.
1700 if ($dbline{$line} =~ s/;9($|\0)/$1/) {
1701 _cancel_breakpoint_temp_enabled_status($filename, $line);
1702 }
69893cff
RGS
1703 }
1704 } ## end if ($dbline{$line} && ...
1705
1706 # Preserve the current stop-or-not, and see if any of the W
1707 # (watch expressions) has changed.
36477c24 1708 my $was_signal = $signal;
69893cff
RGS
1709
1710 # If we have any watch expressions ...
e22ea7cc
RF
1711 if ( $trace & 2 ) {
1712 for ( my $n = 0 ; $n <= $#to_watch ; $n++ ) {
1713 $evalarg = $to_watch[$n];
1714 local $onetimeDump; # Tell DB::eval() to not output results
69893cff
RGS
1715
1716 # Fix context DB::eval() wants to return an array, but
1717 # we need a scalar here.
e22ea7cc
RF
1718 my ($val) = join( "', '", &eval );
1719 $val = ( ( defined $val ) ? "'$val'" : 'undef' );
69893cff
RGS
1720
1721 # Did it change?
e22ea7cc
RF
1722 if ( $val ne $old_watch[$n] ) {
1723
69893cff 1724 # Yep! Show the difference, and fake an interrupt.
e22ea7cc
RF
1725 $signal = 1;
1726 print $OUT <<EOP;
405ff068 1727Watchpoint $n:\t$to_watch[$n] changed:
69893cff
RGS
1728 old value:\t$old_watch[$n]
1729 new value:\t$val
6027b9a3 1730EOP
e22ea7cc 1731 $old_watch[$n] = $val;
69893cff
RGS
1732 } ## end if ($val ne $old_watch...
1733 } ## end for (my $n = 0 ; $n <= ...
1734 } ## end if ($trace & 2)
1735
1736=head2 C<watchfunction()>
1737
1738C<watchfunction()> is a function that can be defined by the user; it is a
1739function which will be run on each entry to C<DB::DB>; it gets the
1740current package, filename, and line as its parameters.
1741
1742The watchfunction can do anything it likes; it is executing in the
1743debugger's context, so it has access to all of the debugger's internal
1744data structures and functions.
1745
1746C<watchfunction()> can control the debugger's actions. Any of the following
1747will cause the debugger to return control to the user's program after
1748C<watchfunction()> executes:
1749
1750=over 4
1751
be9a9b1d
AT
1752=item *
1753
1754Returning a false value from the C<watchfunction()> itself.
1755
1756=item *
1757
1758Altering C<$single> to a false value.
1759
1760=item *
69893cff 1761
be9a9b1d 1762Altering C<$signal> to a false value.
69893cff 1763
be9a9b1d 1764=item *
69893cff 1765
be9a9b1d 1766Turning off the C<4> bit in C<$trace> (this also disables the
69893cff
RGS
1767check for C<watchfunction()>. This can be done with
1768
1769 $trace &= ~4;
1770
1771=back
1772
1773=cut
1774
e22ea7cc 1775 # If there's a user-defined DB::watchfunction, call it with the
69893cff
RGS
1776 # current package, filename, and line. The function executes in
1777 # the DB:: package.
e22ea7cc
RF
1778 if ( $trace & 4 ) { # User-installed watch
1779 return
1780 if watchfunction( $package, $filename, $line )
1781 and not $single
1782 and not $was_signal
1783 and not( $trace & ~4 );
69893cff
RGS
1784 } ## end if ($trace & 4)
1785
e22ea7cc 1786 # Pick up any alteration to $signal in the watchfunction, and
69893cff 1787 # turn off the signal now.
6027b9a3 1788 $was_signal = $signal;
69893cff
RGS
1789 $signal = 0;
1790
1791=head2 GETTING READY TO EXECUTE COMMANDS
1792
1793The debugger decides to take control if single-step mode is on, the
1794C<t> command was entered, or the user generated a signal. If the program
1795has fallen off the end, we set things up so that entering further commands
1796won't cause trouble, and we say that the program is over.
1797
1798=cut
1799
8dc67a69
SF
1800 # Make sure that we always print if asked for explicitly regardless
1801 # of $trace_to_depth .
1802 my $explicit_stop = ($single || $was_signal);
1803
69893cff
RGS
1804 # Check to see if we should grab control ($single true,
1805 # trace set appropriately, or we got a signal).
8dc67a69 1806 if ( $explicit_stop || ( $trace & 1 ) ) {
e22ea7cc 1807
69893cff 1808 # Yes, grab control.
e22ea7cc
RF
1809 if ($slave_editor) {
1810
69893cff 1811 # Tell the editor to update its position.
e22ea7cc
RF
1812 $position = "\032\032$filename:$line:0\n";
1813 print_lineinfo($position);
1814 }
69893cff
RGS
1815
1816=pod
1817
1818Special check: if we're in package C<DB::fake>, we've gone through the
1819C<END> block at least once. We set up everything so that we can continue
1820to enter commands and have a valid context to be in.
1821
1822=cut
1823
e22ea7cc 1824 elsif ( $package eq 'DB::fake' ) {
69893cff 1825
69893cff 1826 # Fallen off the end already.
e22ea7cc
RF
1827 $term || &setterm;
1828 print_help(<<EOP);
405ff068 1829Debugged program terminated. Use B<q> to quit or B<R> to restart,
6b27b0a0
BD
1830 use B<o> I<inhibit_exit> to avoid stopping after program termination,
1831 B<h q>, B<h R> or B<h o> to get additional info.
405ff068 1832EOP
e22ea7cc 1833
69893cff 1834 # Set the DB::eval context appropriately.
e22ea7cc
RF
1835 $package = 'main';
1836 $usercontext =
1837 '($@, $!, $^E, $,, $/, $\, $^W) = @saved;'
1838 . "package $package;"; # this won't let them modify, alas
69893cff 1839 } ## end elsif ($package eq 'DB::fake')
e219e2fb 1840
69893cff 1841=pod
e219e2fb 1842
69893cff
RGS
1843If the program hasn't finished executing, we scan forward to the
1844next executable line, print that out, build the prompt from the file and line
1845number information, and print that.
e219e2fb 1846
69893cff
RGS
1847=cut
1848
e22ea7cc
RF
1849 else {
1850
8dc67a69 1851
69893cff
RGS
1852 # Still somewhere in the midst of execution. Set up the
1853 # debugger prompt.
1854 $sub =~ s/\'/::/; # Swap Perl 4 package separators (') to
e22ea7cc 1855 # Perl 5 ones (sorry, we don't print Klingon
69893cff
RGS
1856 #module names)
1857
e22ea7cc
RF
1858 $prefix = $sub =~ /::/ ? "" : "${'package'}::";
1859 $prefix .= "$sub($filename:";
1860 $after = ( $dbline[$line] =~ /\n$/ ? '' : "\n" );
69893cff
RGS
1861
1862 # Break up the prompt if it's really long.
e22ea7cc
RF
1863 if ( length($prefix) > 30 ) {
1864 $position = "$prefix$line):\n$line:\t$dbline[$line]$after";
1865 $prefix = "";
1866 $infix = ":\t";
1867 }
1868 else {
1869 $infix = "):\t";
1870 $position = "$prefix$line$infix$dbline[$line]$after";
1871 }
69893cff
RGS
1872
1873 # Print current line info, indenting if necessary.
e22ea7cc
RF
1874 if ($frame) {
1875 print_lineinfo( ' ' x $stack_depth,
1876 "$line:\t$dbline[$line]$after" );
1877 }
1878 else {
8dc67a69 1879 depth_print_lineinfo($explicit_stop, $position);
e22ea7cc 1880 }
69893cff
RGS
1881
1882 # Scan forward, stopping at either the end or the next
1883 # unbreakable line.
e22ea7cc
RF
1884 for ( $i = $line + 1 ; $i <= $max && $dbline[$i] == 0 ; ++$i )
1885 { #{ vi
69893cff
RGS
1886
1887 # Drop out on null statements, block closers, and comments.
1888 last if $dbline[$i] =~ /^\s*[\;\}\#\n]/;
1889
1890 # Drop out if the user interrupted us.
1891 last if $signal;
1892
1893 # Append a newline if the line doesn't have one. Can happen
1894 # in eval'ed text, for instance.
e22ea7cc 1895 $after = ( $dbline[$i] =~ /\n$/ ? '' : "\n" );
69893cff
RGS
1896
1897 # Next executable line.
1898 $incr_pos = "$prefix$i$infix$dbline[$i]$after";
1899 $position .= $incr_pos;
1900 if ($frame) {
e22ea7cc 1901
69893cff 1902 # Print it indented if tracing is on.
e22ea7cc
RF
1903 print_lineinfo( ' ' x $stack_depth,
1904 "$i:\t$dbline[$i]$after" );
69893cff
RGS
1905 }
1906 else {
8dc67a69 1907 depth_print_lineinfo($explicit_stop, $incr_pos);
69893cff
RGS
1908 }
1909 } ## end for ($i = $line + 1 ; $i...
1910 } ## end else [ if ($slave_editor)
1911 } ## end if ($single || ($trace...
1912
1913=pod
1914
1915If there's an action to be executed for the line we stopped at, execute it.
1916If there are any preprompt actions, execute those as well.
e219e2fb
RF
1917
1918=cut
1919
69893cff
RGS
1920 # If there's an action, do it now.
1921 $evalarg = $action, &eval if $action;
e219e2fb 1922
69893cff
RGS
1923 # Are we nested another level (e.g., did we evaluate a function
1924 # that had a breakpoint in it at the debugger prompt)?
e22ea7cc
RF
1925 if ( $single || $was_signal ) {
1926
69893cff 1927 # Yes, go down a level.
e22ea7cc 1928 local $level = $level + 1;
69893cff
RGS
1929
1930 # Do any pre-prompt actions.
e22ea7cc
RF
1931 foreach $evalarg (@$pre) {
1932 &eval;
1933 }
69893cff
RGS
1934
1935 # Complain about too much recursion if we passed the limit.
e22ea7cc 1936 print $OUT $stack_depth . " levels deep in subroutine calls!\n"
69893cff
RGS
1937 if $single & 4;
1938
1939 # The line we're currently on. Set $incr to -1 to stay here
1940 # until we get a command that tells us to advance.
e22ea7cc
RF
1941 $start = $line;
1942 $incr = -1; # for backward motion.
69893cff
RGS
1943
1944 # Tack preprompt debugger actions ahead of any actual input.
e22ea7cc 1945 @typeahead = ( @$pretype, @typeahead );
69893cff
RGS
1946
1947=head2 WHERE ARE WE?
1948
1949XXX Relocate this section?
1950
1951The debugger normally shows the line corresponding to the current line of
1952execution. Sometimes, though, we want to see the next line, or to move elsewhere
1953in the file. This is done via the C<$incr>, C<$start>, and C<$max> variables.
1954
be9a9b1d
AT
1955C<$incr> controls by how many lines the I<current> line should move forward
1956after a command is executed. If set to -1, this indicates that the I<current>
69893cff
RGS
1957line shouldn't change.
1958
be9a9b1d 1959C<$start> is the I<current> line. It is used for things like knowing where to
69893cff
RGS
1960move forwards or backwards from when doing an C<L> or C<-> command.
1961
1962C<$max> tells the debugger where the last line of the current file is. It's
1963used to terminate loops most often.
1964
1965=head2 THE COMMAND LOOP
1966
1967Most of C<DB::DB> is actually a command parsing and dispatch loop. It comes
1968in two parts:
1969
1970=over 4
1971
be9a9b1d
AT
1972=item *
1973
1974The outer part of the loop, starting at the C<CMD> label. This loop
69893cff
RGS
1975reads a command and then executes it.
1976
be9a9b1d
AT
1977=item *
1978
1979The inner part of the loop, starting at the C<PIPE> label. This part
69893cff
RGS
1980is wholly contained inside the C<CMD> block and only executes a command.
1981Used to handle commands running inside a pager.
1982
1983=back
1984
1985So why have two labels to restart the loop? Because sometimes, it's easier to
1986have a command I<generate> another command and then re-execute the loop to do
1987the new command. This is faster, but perhaps a bit more convoluted.
1988
1989=cut
1990
1991 # The big command dispatch loop. It keeps running until the
1992 # user yields up control again.
1993 #
1994 # If we have a terminal for input, and we get something back
1995 # from readline(), keep on processing.
e22ea7cc
RF
1996 CMD:
1997 while (
1998
69893cff 1999 # We have a terminal, or can get one ...
e22ea7cc
RF
2000 ( $term || &setterm ),
2001
69893cff 2002 # ... and it belogs to this PID or we get one for this PID ...
e22ea7cc
RF
2003 ( $term_pid == $$ or resetterm(1) ),
2004
69893cff 2005 # ... and we got a line of command input ...
e22ea7cc
RF
2006 defined(
2007 $cmd = &readline(
2cbb2ee1 2008 "$pidprompt $tid DB"
e22ea7cc
RF
2009 . ( '<' x $level )
2010 . ( $#hist + 1 )
2011 . ( '>' x $level ) . " "
69893cff
RGS
2012 )
2013 )
2014 )
2015 {
e22ea7cc 2016
2cbb2ee1 2017 share($cmd);
69893cff
RGS
2018 # ... try to execute the input as debugger commands.
2019
2020 # Don't stop running.
2021 $single = 0;
2022
2023 # No signal is active.
2024 $signal = 0;
2025
2026 # Handle continued commands (ending with \):
e22ea7cc
RF
2027 $cmd =~ s/\\$/\n/ && do {
2028 $cmd .= &readline(" cont: ");
2029 redo CMD;
2030 };
69893cff
RGS
2031
2032=head4 The null command
2033
be9a9b1d 2034A newline entered by itself means I<re-execute the last command>. We grab the
69893cff
RGS
2035command out of C<$laststep> (where it was recorded previously), and copy it
2036back into C<$cmd> to be executed below. If there wasn't any previous command,
2037we'll do nothing below (no command will match). If there was, we also save it
2038in the command history and fall through to allow the command parsing to pick
2039it up.
2040
2041=cut
2042
2043 # Empty input means repeat the last command.
e22ea7cc
RF
2044 $cmd =~ /^$/ && ( $cmd = $laststep );
2045 chomp($cmd); # get rid of the annoying extra newline
2046 push( @hist, $cmd ) if length($cmd) > 1;
2047 push( @truehist, $cmd );
2cbb2ee1
RGS
2048 share(@hist);
2049 share(@truehist);
e22ea7cc
RF
2050
2051 # This is a restart point for commands that didn't arrive
2052 # via direct user input. It allows us to 'redo PIPE' to
2053 # re-execute command processing without reading a new command.
69893cff 2054 PIPE: {
e22ea7cc
RF
2055 $cmd =~ s/^\s+//s; # trim annoying leading whitespace
2056 $cmd =~ s/\s+$//s; # trim annoying trailing whitespace
2057 ($i) = split( /\s+/, $cmd );
69893cff
RGS
2058
2059=head3 COMMAND ALIASES
2060
2061The debugger can create aliases for commands (these are stored in the
2062C<%alias> hash). Before a command is executed, the command loop looks it up
2063in the alias hash and substitutes the contents of the alias for the command,
2064completely replacing it.
2065
2066=cut
2067
2068 # See if there's an alias for the command, and set it up if so.
e22ea7cc
RF
2069 if ( $alias{$i} ) {
2070
69893cff
RGS
2071 # Squelch signal handling; we want to keep control here
2072 # if something goes loco during the alias eval.
2073 local $SIG{__DIE__};
2074 local $SIG{__WARN__};
2075
2076 # This is a command, so we eval it in the DEBUGGER's
2077 # scope! Otherwise, we can't see the special debugger
2078 # variables, or get to the debugger's subs. (Well, we
2079 # _could_, but why make it even more complicated?)
2080 eval "\$cmd =~ $alias{$i}";
2081 if ($@) {
2082 local $\ = '';
1f874cb6 2083 print $OUT "Couldn't evaluate '$i' alias: $@";
69893cff
RGS
2084 next CMD;
2085 }
2086 } ## end if ($alias{$i})
2087
2088=head3 MAIN-LINE COMMANDS
2089
2090All of these commands work up to and after the program being debugged has
2091terminated.
2092
2093=head4 C<q> - quit
2094
2095Quit the debugger. This entails setting the C<$fall_off_end> flag, so we don't
2096try to execute further, cleaning any restart-related stuff out of the
2097environment, and executing with the last value of C<$?>.
2098
2099=cut
2100
2101 $cmd =~ /^q$/ && do {
2102 $fall_off_end = 1;
2103 clean_ENV();
2104 exit $?;
2105 };
2106
611272bb 2107=head4 C<t> - trace [n]
69893cff
RGS
2108
2109Turn tracing on or off. Inverts the appropriate bit in C<$trace> (q.v.).
611272bb 2110If level is specified, set C<$trace_to_depth>.
69893cff
RGS
2111
2112=cut
2113
611272bb
PS
2114 $cmd =~ /^t(?:\s+(\d+))?$/ && do {
2115 my $levels = $1;
e22ea7cc
RF
2116 $trace ^= 1;
2117 local $\ = '';
611272bb 2118 $trace_to_depth = $levels ? $stack_depth + $levels : 1E9;
e22ea7cc 2119 print $OUT "Trace = "
611272bb
PS
2120 . ( ( $trace & 1 )
2121 ? ( $levels ? "on (to level $trace_to_depth)" : "on" )
2122 : "off" ) . "\n";
e22ea7cc
RF
2123 next CMD;
2124 };
69893cff
RGS
2125
2126=head4 C<S> - list subroutines matching/not matching a pattern
2127
2128Walks through C<%sub>, checking to see whether or not to print the name.
2129
2130=cut
2131
e22ea7cc 2132 $cmd =~ /^S(\s+(!)?(.+))?$/ && do {
69893cff 2133
e22ea7cc 2134 $Srev = defined $2; # Reverse scan?
69893cff
RGS
2135 $Spatt = $3; # The pattern (if any) to use.
2136 $Snocheck = !defined $1; # No args - print all subs.
2137
2138 # Need to make these sane here.
e22ea7cc
RF
2139 local $\ = '';
2140 local $, = '';
69893cff
RGS
2141
2142 # Search through the debugger's magical hash of subs.
2143 # If $nocheck is true, just print the sub name.
2144 # Otherwise, check it against the pattern. We then use
2145 # the XOR trick to reverse the condition as required.
e22ea7cc
RF
2146 foreach $subname ( sort( keys %sub ) ) {
2147 if ( $Snocheck or $Srev ^ ( $subname =~ /$Spatt/ ) ) {
2148 print $OUT $subname, "\n";
2149 }
2150 }
2151 next CMD;
2152 };
69893cff
RGS
2153
2154=head4 C<X> - list variables in current package
2155
2156Since the C<V> command actually processes this, just change this to the
2157appropriate C<V> command and fall through.
2158
2159=cut
2160
e22ea7cc 2161 $cmd =~ s/^X\b/V $package/;
69893cff
RGS
2162
2163=head4 C<V> - list variables
2164
2165Uses C<dumpvar.pl> to dump out the current values for selected variables.
2166
2167=cut
2168
2169 # Bare V commands get the currently-being-debugged package
2170 # added.
e22ea7cc
RF
2171 $cmd =~ /^V$/ && do {
2172 $cmd = "V $package";
2173 };
69893cff
RGS
2174
2175 # V - show variables in package.
2176 $cmd =~ /^V\b\s*(\S+)\s*(.*)/ && do {
e22ea7cc 2177
69893cff
RGS
2178 # Save the currently selected filehandle and
2179 # force output to debugger's filehandle (dumpvar
2180 # just does "print" for output).
e22ea7cc 2181 local ($savout) = select($OUT);
69893cff
RGS
2182
2183 # Grab package name and variables to dump.
e22ea7cc
RF
2184 $packname = $1;
2185 @vars = split( ' ', $2 );
69893cff
RGS
2186
2187 # If main::dumpvar isn't here, get it.
e81465be 2188 do 'dumpvar.pl' || die $@ unless defined &main::dumpvar;
e22ea7cc
RF
2189 if ( defined &main::dumpvar ) {
2190
69893cff
RGS
2191 # We got it. Turn off subroutine entry/exit messages
2192 # for the moment, along with return values.
e22ea7cc
RF
2193 local $frame = 0;
2194 local $doret = -2;
69893cff
RGS
2195
2196 # must detect sigpipe failures - not catching
2197 # then will cause the debugger to die.
2198 eval {
2199 &main::dumpvar(
2200 $packname,
2201 defined $option{dumpDepth}
e22ea7cc
RF
2202 ? $option{dumpDepth}
2203 : -1, # assume -1 unless specified
69893cff 2204 @vars
e22ea7cc
RF
2205 );
2206 };
2207
2208 # The die doesn't need to include the $@, because
2209 # it will automatically get propagated for us.
2210 if ($@) {
2211 die unless $@ =~ /dumpvar print failed/;
2212 }
2213 } ## end if (defined &main::dumpvar)
2214 else {
2215
2216 # Couldn't load dumpvar.
2217 print $OUT "dumpvar.pl not available.\n";
2218 }
69893cff 2219
69893cff 2220 # Restore the output filehandle, and go round again.
e22ea7cc
RF
2221 select($savout);
2222 next CMD;
2223 };
69893cff
RGS
2224
2225=head4 C<x> - evaluate and print an expression
2226
2227Hands the expression off to C<DB::eval>, setting it up to print the value
2228via C<dumpvar.pl> instead of just printing it directly.
2229
2230=cut
2231
e22ea7cc
RF
2232 $cmd =~ s/^x\b/ / && do { # Remainder gets done by DB::eval()
2233 $onetimeDump = 'dump'; # main::dumpvar shows the output
69893cff
RGS
2234
2235 # handle special "x 3 blah" syntax XXX propagate
2236 # doc back to special variables.
e22ea7cc
RF
2237 if ( $cmd =~ s/^\s*(\d+)(?=\s)/ / ) {
2238 $onetimedumpDepth = $1;
2239 }
2240 };
69893cff
RGS
2241
2242=head4 C<m> - print methods
2243
2244Just uses C<DB::methods> to determine what methods are available.
2245
2246=cut
2247
e22ea7cc
RF
2248 $cmd =~ s/^m\s+([\w:]+)\s*$/ / && do {
2249 methods($1);
2250 next CMD;
2251 };
69893cff
RGS
2252
2253 # m expr - set up DB::eval to do the work
e22ea7cc
RF
2254 $cmd =~ s/^m\b/ / && do { # Rest gets done by DB::eval()
2255 $onetimeDump = 'methods'; # method output gets used there
2256 };
69893cff
RGS
2257
2258=head4 C<f> - switch files
2259
2260=cut
2261
e22ea7cc
RF
2262 $cmd =~ /^f\b\s*(.*)/ && do {
2263 $file = $1;
2264 $file =~ s/\s+$//;
69893cff
RGS
2265
2266 # help for no arguments (old-style was return from sub).
e22ea7cc
RF
2267 if ( !$file ) {
2268 print $OUT
2269 "The old f command is now the r command.\n"; # hint
2270 print $OUT "The new f command switches filenames.\n";
2271 next CMD;
2272 } ## end if (!$file)
69893cff
RGS
2273
2274 # if not in magic file list, try a close match.
e22ea7cc
RF
2275 if ( !defined $main::{ '_<' . $file } ) {
2276 if ( ($try) = grep( m#^_<.*$file#, keys %main:: ) ) {
2277 {
2278 $try = substr( $try, 2 );
1f874cb6 2279 print $OUT "Choosing $try matching '$file':\n";
e22ea7cc
RF
2280 $file = $try;
2281 }
2282 } ## end if (($try) = grep(m#^_<.*$file#...
2283 } ## end if (!defined $main::{ ...
69893cff
RGS
2284
2285 # If not successfully switched now, we failed.
e22ea7cc 2286 if ( !defined $main::{ '_<' . $file } ) {
1f874cb6 2287 print $OUT "No file matching '$file' is loaded.\n";
e22ea7cc
RF
2288 next CMD;
2289 }
69893cff 2290
e22ea7cc
RF
2291 # We switched, so switch the debugger internals around.
2292 elsif ( $file ne $filename ) {
2293 *dbline = $main::{ '_<' . $file };
2294 $max = $#dbline;
2295 $filename = $file;
2296 $start = 1;
2297 $cmd = "l";
2298 } ## end elsif ($file ne $filename)
2299
2300 # We didn't switch; say we didn't.
2301 else {
2302 print $OUT "Already in $file.\n";
2303 next CMD;
2304 }
2305 };
69893cff
RGS
2306
2307=head4 C<.> - return to last-executed line.
2308
2309We set C<$incr> to -1 to indicate that the debugger shouldn't move ahead,
2310and then we look up the line in the magical C<%dbline> hash.
2311
2312=cut
2313
2314 # . command.
e22ea7cc
RF
2315 $cmd =~ /^\.$/ && do {
2316 $incr = -1; # stay at current line
69893cff
RGS
2317
2318 # Reset everything to the old location.
e22ea7cc
RF
2319 $start = $line;
2320 $filename = $filename_ini;
2321 *dbline = $main::{ '_<' . $filename };
2322 $max = $#dbline;
69893cff
RGS
2323
2324 # Now where are we?
e22ea7cc
RF
2325 print_lineinfo($position);
2326 next CMD;
2327 };
69893cff
RGS
2328
2329=head4 C<-> - back one window
2330
2331We change C<$start> to be one window back; if we go back past the first line,
2332we set it to be the first line. We ser C<$incr> to put us back at the
2333currently-executing line, and then put a C<l $start +> (list one window from
2334C<$start>) in C<$cmd> to be executed later.
2335
2336=cut
2337
2338 # - - back a window.
e22ea7cc
RF
2339 $cmd =~ /^-$/ && do {
2340
69893cff 2341 # back up by a window; go to 1 if back too far.
e22ea7cc
RF
2342 $start -= $incr + $window + 1;
2343 $start = 1 if $start <= 0;
2344 $incr = $window - 1;
69893cff
RGS
2345
2346 # Generate and execute a "l +" command (handled below).
e22ea7cc
RF
2347 $cmd = 'l ' . ($start) . '+';
2348 };
69893cff
RGS
2349
2350=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>, {, {{>
2351
2352In Perl 5.8.0, a realignment of the commands was done to fix up a number of
2353problems, most notably that the default case of several commands destroying
2354the user's work in setting watchpoints, actions, etc. We wanted, however, to
2355retain the old commands for those who were used to using them or who preferred
2356them. At this point, we check for the new commands and call C<cmd_wrapper> to
2357deal with them instead of processing them in-line.
2358
2359=cut
2360
2361 # All of these commands were remapped in perl 5.8.0;
e22ea7cc 2362 # we send them off to the secondary dispatcher (see below).
2cbb2ee1 2363 $cmd =~ /^([aAbBeEhilLMoOPvwW]\b|[<>\{]{1,2})\s*(.*)/so && do {
e22ea7cc
RF
2364 &cmd_wrapper( $1, $2, $line );
2365 next CMD;
2366 };
69893cff
RGS
2367
2368=head4 C<y> - List lexicals in higher scope
2369
2370Uses C<PadWalker> to find the lexicals supplied as arguments in a scope
2371above the current one and then displays then using C<dumpvar.pl>.
2372
2373=cut
2374
2375 $cmd =~ /^y(?:\s+(\d*)\s*(.*))?$/ && do {
2376
2377 # See if we've got the necessary support.
2378 eval { require PadWalker; PadWalker->VERSION(0.08) }
2379 or &warn(
2380 $@ =~ /locate/
2381 ? "PadWalker module not found - please install\n"
2382 : $@
2383 )
2384 and next CMD;
2385
2386 # Load up dumpvar if we don't have it. If we can, that is.
e81465be 2387 do 'dumpvar.pl' || die $@ unless defined &main::dumpvar;
69893cff
RGS
2388 defined &main::dumpvar
2389 or print $OUT "dumpvar.pl not available.\n"
2390 and next CMD;
2391
2392 # Got all the modules we need. Find them and print them.
e22ea7cc 2393 my @vars = split( ' ', $2 || '' );
69893cff
RGS
2394
2395 # Find the pad.
e22ea7cc 2396 my $h = eval { PadWalker::peek_my( ( $1 || 0 ) + 1 ) };
69893cff
RGS
2397
2398 # Oops. Can't find it.
2399 $@ and $@ =~ s/ at .*//, &warn($@), next CMD;
2400
2401 # Show the desired vars with dumplex().
2402 my $savout = select($OUT);
2403
2404 # Have dumplex dump the lexicals.
e22ea7cc 2405 dumpvar::dumplex( $_, $h->{$_},
69893cff 2406 defined $option{dumpDepth} ? $option{dumpDepth} : -1,
e22ea7cc
RF
2407 @vars )
2408 for sort keys %$h;
69893cff
RGS
2409 select($savout);
2410 next CMD;
2411 };
2412
2413=head3 COMMANDS NOT WORKING AFTER PROGRAM ENDS
2414
2415All of the commands below this point don't work after the program being
2416debugged has ended. All of them check to see if the program has ended; this
2417allows the commands to be relocated without worrying about a 'line of
2418demarcation' above which commands can be entered anytime, and below which
2419they can't.
2420
2421=head4 C<n> - single step, but don't trace down into subs
2422
2423Done by setting C<$single> to 2, which forces subs to execute straight through
be9a9b1d 2424when entered (see C<DB::sub>). We also save the C<n> command in C<$laststep>,
69893cff
RGS
2425so a null command knows what to re-execute.
2426
2427=cut
2428
e22ea7cc 2429 # n - next
69893cff
RGS
2430 $cmd =~ /^n$/ && do {
2431 end_report(), next CMD if $finished and $level <= 1;
e22ea7cc 2432
69893cff
RGS
2433 # Single step, but don't enter subs.
2434 $single = 2;
e22ea7cc 2435
69893cff 2436 # Save for empty command (repeat last).
e22ea7cc
RF
2437 $laststep = $cmd;
2438 last CMD;
2439 };
69893cff
RGS
2440
2441=head4 C<s> - single-step, entering subs
2442
be9a9b1d 2443Sets C<$single> to 1, which causes C<DB::sub> to continue tracing inside
69893cff
RGS
2444subs. Also saves C<s> as C<$lastcmd>.
2445
2446=cut
2447
2448 # s - single step.
2449 $cmd =~ /^s$/ && do {
e22ea7cc 2450
69893cff
RGS
2451 # Get out and restart the command loop if program
2452 # has finished.
e22ea7cc
RF
2453 end_report(), next CMD if $finished and $level <= 1;
2454
69893cff 2455 # Single step should enter subs.
e22ea7cc
RF
2456 $single = 1;
2457
69893cff 2458 # Save for empty command (repeat last).
e22ea7cc
RF
2459 $laststep = $cmd;
2460 last CMD;
2461 };
69893cff
RGS
2462
2463=head4 C<c> - run continuously, setting an optional breakpoint
2464
2465Most of the code for this command is taken up with locating the optional
2466breakpoint, which is either a subroutine name or a line number. We set
2467the appropriate one-time-break in C<@dbline> and then turn off single-stepping
2468in this and all call levels above this one.
2469
2470=cut
2471
2472 # c - start continuous execution.
2473 $cmd =~ /^c\b\s*([\w:]*)\s*$/ && do {
e22ea7cc 2474
69893cff
RGS
2475 # Hey, show's over. The debugged program finished
2476 # executing already.
2477 end_report(), next CMD if $finished and $level <= 1;
2478
2479 # Capture the place to put a one-time break.
2480 $subname = $i = $1;
2481
e22ea7cc
RF
2482 # Probably not needed, since we finish an interactive
2483 # sub-session anyway...
2484 # local $filename = $filename;
2485 # local *dbline = *dbline; # XXX Would this work?!
69893cff
RGS
2486 #
2487 # The above question wonders if localizing the alias
2488 # to the magic array works or not. Since it's commented
2489 # out, we'll just leave that to speculation for now.
2490
2491 # If the "subname" isn't all digits, we'll assume it
2492 # is a subroutine name, and try to find it.
e22ea7cc
RF
2493 if ( $subname =~ /\D/ ) { # subroutine name
2494 # Qualify it to the current package unless it's
2495 # already qualified.
69893cff
RGS
2496 $subname = $package . "::" . $subname
2497 unless $subname =~ /::/;
e22ea7cc 2498
69893cff
RGS
2499 # find_sub will return "file:line_number" corresponding
2500 # to where the subroutine is defined; we call find_sub,
e22ea7cc 2501 # break up the return value, and assign it in one
69893cff 2502 # operation.
e22ea7cc 2503 ( $file, $i ) = ( find_sub($subname) =~ /^(.*):(.*)$/ );
69893cff
RGS
2504
2505 # Force the line number to be numeric.
e22ea7cc 2506 $i += 0;
69893cff
RGS
2507
2508 # If we got a line number, we found the sub.
e22ea7cc
RF
2509 if ($i) {
2510
69893cff
RGS
2511 # Switch all the debugger's internals around so
2512 # we're actually working with that file.
e22ea7cc
RF
2513 $filename = $file;
2514 *dbline = $main::{ '_<' . $filename };
2515
69893cff 2516 # Mark that there's a breakpoint in this file.
e22ea7cc
RF
2517 $had_breakpoints{$filename} |= 1;
2518
69893cff
RGS
2519 # Scan forward to the first executable line
2520 # after the 'sub whatever' line.
e22ea7cc
RF
2521 $max = $#dbline;
2522 ++$i while $dbline[$i] == 0 && $i < $max;
2523 } ## end if ($i)
69893cff
RGS
2524
2525 # We didn't find a sub by that name.
e22ea7cc
RF
2526 else {
2527 print $OUT "Subroutine $subname not found.\n";
2528 next CMD;
2529 }
2530 } ## end if ($subname =~ /\D/)
69893cff
RGS
2531
2532 # At this point, either the subname was all digits (an
2533 # absolute line-break request) or we've scanned through
2534 # the code following the definition of the sub, looking
2535 # for an executable, which we may or may not have found.
2536 #
2537 # If $i (which we set $subname from) is non-zero, we
e22ea7cc
RF
2538 # got a request to break at some line somewhere. On
2539 # one hand, if there wasn't any real subroutine name
2540 # involved, this will be a request to break in the current
2541 # file at the specified line, so we have to check to make
69893cff
RGS
2542 # sure that the line specified really is breakable.
2543 #
2544 # On the other hand, if there was a subname supplied, the
3c4b39be 2545 # preceding block has moved us to the proper file and
69893cff
RGS
2546 # location within that file, and then scanned forward
2547 # looking for the next executable line. We have to make
2548 # sure that one was found.
2549 #
2550 # On the gripping hand, we can't do anything unless the
2551 # current value of $i points to a valid breakable line.
2552 # Check that.
e22ea7cc
RF
2553 if ($i) {
2554
69893cff 2555 # Breakable?
e22ea7cc
RF
2556 if ( $dbline[$i] == 0 ) {
2557 print $OUT "Line $i not breakable.\n";
2558 next CMD;
2559 }
2560
69893cff 2561 # Yes. Set up the one-time-break sigil.
e22ea7cc 2562 $dbline{$i} =~ s/($|\0)/;9$1/; # add one-time-only b.p.
5d5d9ea3 2563 _enable_breakpoint_temp_enabled_status($filename, $i);
e22ea7cc 2564 } ## end if ($i)
69893cff
RGS
2565
2566 # Turn off stack tracing from here up.
e22ea7cc
RF
2567 for ( $i = 0 ; $i <= $stack_depth ; ) {
2568 $stack[ $i++ ] &= ~1;
2569 }
2570 last CMD;
2571 };
69893cff
RGS
2572
2573=head4 C<r> - return from a subroutine
2574
2575For C<r> to work properly, the debugger has to stop execution again
2576immediately after the return is executed. This is done by forcing
2577single-stepping to be on in the call level above the current one. If
2578we are printing return values when a C<r> is executed, set C<$doret>
2579appropriately, and force us out of the command loop.
2580
2581=cut
2582
2583 # r - return from the current subroutine.
e22ea7cc
RF
2584 $cmd =~ /^r$/ && do {
2585
98dc9551 2586 # Can't do anything if the program's over.
e22ea7cc
RF
2587 end_report(), next CMD if $finished and $level <= 1;
2588
69893cff 2589 # Turn on stack trace.
e22ea7cc
RF
2590 $stack[$stack_depth] |= 1;
2591
69893cff 2592 # Print return value unless the stack is empty.
e22ea7cc
RF
2593 $doret = $option{PrintRet} ? $stack_depth - 1 : -2;
2594 last CMD;
2595 };
69893cff 2596
69893cff
RGS
2597=head4 C<T> - stack trace
2598
2599Just calls C<DB::print_trace>.
2600
2601=cut
2602
e22ea7cc
RF
2603 $cmd =~ /^T$/ && do {
2604 print_trace( $OUT, 1 ); # skip DB
2605 next CMD;
2606 };
69893cff
RGS
2607
2608=head4 C<w> - List window around current line.
2609
2610Just calls C<DB::cmd_w>.
2611
2612=cut
2613
e22ea7cc 2614 $cmd =~ /^w\b\s*(.*)/s && do { &cmd_w( 'w', $1 ); next CMD; };
69893cff
RGS
2615
2616=head4 C<W> - watch-expression processing.
2617
2618Just calls C<DB::cmd_W>.
2619
2620=cut
2621
e22ea7cc 2622 $cmd =~ /^W\b\s*(.*)/s && do { &cmd_W( 'W', $1 ); next CMD; };
69893cff
RGS
2623
2624=head4 C</> - search forward for a string in the source
2625
2626We take the argument and treat it as a pattern. If it turns out to be a
2627bad one, we return the error we got from trying to C<eval> it and exit.
2628If not, we create some code to do the search and C<eval> it so it can't
2629mess us up.
2630
2631=cut
2632
e22ea7cc 2633 $cmd =~ /^\/(.*)$/ && do {
69893cff
RGS
2634
2635 # The pattern as a string.
e22ea7cc 2636 $inpat = $1;
69893cff
RGS
2637
2638 # Remove the final slash.
e22ea7cc 2639 $inpat =~ s:([^\\])/$:$1:;
69893cff
RGS
2640
2641 # If the pattern isn't null ...
e22ea7cc 2642 if ( $inpat ne "" ) {
69893cff
RGS
2643
2644 # Turn of warn and die procesing for a bit.
e22ea7cc
RF
2645 local $SIG{__DIE__};
2646 local $SIG{__WARN__};
69893cff
RGS
2647
2648 # Create the pattern.
e22ea7cc
RF
2649 eval '$inpat =~ m' . "\a$inpat\a";
2650 if ( $@ ne "" ) {
2651
69893cff 2652 # Oops. Bad pattern. No biscuit.
e22ea7cc 2653 # Print the eval error and go back for more
69893cff 2654 # commands.
e22ea7cc
RF
2655 print $OUT "$@";
2656 next CMD;
2657 }
2658 $pat = $inpat;
2659 } ## end if ($inpat ne "")
69893cff
RGS
2660
2661 # Set up to stop on wrap-around.
e22ea7cc 2662 $end = $start;
69893cff
RGS
2663
2664 # Don't move off the current line.
e22ea7cc 2665 $incr = -1;
69893cff
RGS
2666
2667 # Done in eval so nothing breaks if the pattern
2668 # does something weird.
e22ea7cc
RF
2669 eval '
2670 for (;;) {
69893cff 2671 # Move ahead one line.
e22ea7cc 2672 ++$start;
69893cff
RGS
2673
2674 # Wrap if we pass the last line.
e22ea7cc 2675 $start = 1 if ($start > $max);
69893cff
RGS
2676
2677 # Stop if we have gotten back to this line again,
e22ea7cc 2678 last if ($start == $end);
69893cff
RGS
2679
2680 # A hit! (Note, though, that we are doing
2681 # case-insensitive matching. Maybe a qr//
2682 # expression would be better, so the user could
2683 # do case-sensitive matching if desired.
e22ea7cc
RF
2684 if ($dbline[$start] =~ m' . "\a$pat\a" . 'i) {
2685 if ($slave_editor) {
69893cff 2686 # Handle proper escaping in the slave.
e22ea7cc
RF
2687 print $OUT "\032\032$filename:$start:0\n";
2688 }
2689 else {
69893cff 2690 # Just print the line normally.
e22ea7cc
RF
2691 print $OUT "$start:\t",$dbline[$start],"\n";
2692 }
69893cff 2693 # And quit since we found something.
e22ea7cc
RF
2694 last;
2695 }
2696 } ';
2697
69893cff 2698 # If we wrapped, there never was a match.
e22ea7cc
RF
2699 print $OUT "/$pat/: not found\n" if ( $start == $end );
2700 next CMD;
2701 };
69893cff
RGS
2702
2703=head4 C<?> - search backward for a string in the source
2704
2705Same as for C</>, except the loop runs backwards.
2706
2707=cut
2708
2709 # ? - backward pattern search.
e22ea7cc 2710 $cmd =~ /^\?(.*)$/ && do {
69893cff
RGS
2711
2712 # Get the pattern, remove trailing question mark.
e22ea7cc
RF
2713 $inpat = $1;
2714 $inpat =~ s:([^\\])\?$:$1:;
69893cff
RGS
2715
2716 # If we've got one ...
e22ea7cc 2717 if ( $inpat ne "" ) {
69893cff
RGS
2718
2719 # Turn off die & warn handlers.
e22ea7cc
RF
2720 local $SIG{__DIE__};
2721 local $SIG{__WARN__};
2722 eval '$inpat =~ m' . "\a$inpat\a";
2723
2724 if ( $@ ne "" ) {
2725
69893cff 2726 # Ouch. Not good. Print the error.
e22ea7cc
RF
2727 print $OUT $@;
2728 next CMD;
2729 }
2730 $pat = $inpat;
69893cff 2731 } ## end if ($inpat ne "")
e22ea7cc 2732
69893cff 2733 # Where we are now is where to stop after wraparound.
e22ea7cc 2734 $end = $start;
69893cff
RGS
2735
2736 # Don't move away from this line.
e22ea7cc 2737 $incr = -1;
69893cff
RGS
2738
2739 # Search inside the eval to prevent pattern badness
2740 # from killing us.
e22ea7cc
RF
2741 eval '
2742 for (;;) {
69893cff 2743 # Back up a line.
e22ea7cc 2744 --$start;
69893cff
RGS
2745
2746 # Wrap if we pass the first line.
e22ea7cc
RF
2747
2748 $start = $max if ($start <= 0);
69893cff
RGS
2749
2750 # Quit if we get back where we started,
e22ea7cc 2751 last if ($start == $end);
69893cff
RGS
2752
2753 # Match?
e22ea7cc
RF
2754 if ($dbline[$start] =~ m' . "\a$pat\a" . 'i) {
2755 if ($slave_editor) {
69893cff 2756 # Yep, follow slave editor requirements.
e22ea7cc
RF
2757 print $OUT "\032\032$filename:$start:0\n";
2758 }
2759 else {
69893cff 2760 # Yep, just print normally.
e22ea7cc
RF
2761 print $OUT "$start:\t",$dbline[$start],"\n";
2762 }
69893cff
RGS
2763
2764 # Found, so done.
e22ea7cc
RF
2765 last;
2766 }
2767 } ';
2768
2769 # Say we failed if the loop never found anything,
2770 print $OUT "?$pat?: not found\n" if ( $start == $end );
2771 next CMD;
2772 };
69893cff
RGS
2773
2774=head4 C<$rc> - Recall command
2775
2776Manages the commands in C<@hist> (which is created if C<Term::ReadLine> reports
2777that the terminal supports history). It find the the command required, puts it
2778into C<$cmd>, and redoes the loop to execute it.
2779
2780=cut
2781
e22ea7cc
RF
2782 # $rc - recall command.
2783 $cmd =~ /^$rc+\s*(-)?(\d+)?$/ && do {
69893cff
RGS
2784
2785 # No arguments, take one thing off history.
e22ea7cc 2786 pop(@hist) if length($cmd) > 1;
69893cff 2787
e22ea7cc 2788 # Relative (- found)?
69893cff 2789 # Y - index back from most recent (by 1 if bare minus)
e22ea7cc 2790 # N - go to that particular command slot or the last
69893cff 2791 # thing if nothing following.
e22ea7cc 2792 $i = $1 ? ( $#hist - ( $2 || 1 ) ) : ( $2 || $#hist );
69893cff
RGS
2793
2794 # Pick out the command desired.
e22ea7cc 2795 $cmd = $hist[$i];
69893cff
RGS
2796
2797 # Print the command to be executed and restart the loop
2798 # with that command in the buffer.
e22ea7cc
RF
2799 print $OUT $cmd, "\n";
2800 redo CMD;
2801 };
69893cff
RGS
2802
2803=head4 C<$sh$sh> - C<system()> command
2804
2805Calls the C<DB::system()> to handle the command. This keeps the C<STDIN> and
2806C<STDOUT> from getting messed up.
2807
2808=cut
2809
2810 # $sh$sh - run a shell command (if it's all ASCII).
2811 # Can't run shell commands with Unicode in the debugger, hmm.
e22ea7cc
RF
2812 $cmd =~ /^$sh$sh\s*([\x00-\xff]*)/ && do {
2813
69893cff 2814 # System it.
e22ea7cc
RF
2815 &system($1);
2816 next CMD;
2817 };
69893cff
RGS
2818
2819=head4 C<$rc I<pattern> $rc> - Search command history
2820
2821Another command to manipulate C<@hist>: this one searches it with a pattern.
be9a9b1d 2822If a command is found, it is placed in C<$cmd> and executed via C<redo>.
69893cff
RGS
2823
2824=cut
2825
e22ea7cc
RF
2826 # $rc pattern $rc - find a command in the history.
2827 $cmd =~ /^$rc([^$rc].*)$/ && do {
2828
69893cff 2829 # Create the pattern to use.
e22ea7cc 2830 $pat = "^$1";
69893cff
RGS
2831
2832 # Toss off last entry if length is >1 (and it always is).
e22ea7cc 2833 pop(@hist) if length($cmd) > 1;
69893cff
RGS
2834
2835 # Look backward through the history.
e22ea7cc
RF
2836 for ( $i = $#hist ; $i ; --$i ) {
2837
69893cff 2838 # Stop if we find it.
e22ea7cc
RF
2839 last if $hist[$i] =~ /$pat/;
2840 }
2841
2842 if ( !$i ) {
69893cff 2843
69893cff 2844 # Never found it.
e22ea7cc
RF
2845 print $OUT "No such command!\n\n";
2846 next CMD;
2847 }
69893cff
RGS
2848
2849 # Found it. Put it in the buffer, print it, and process it.
e22ea7cc
RF
2850 $cmd = $hist[$i];
2851 print $OUT $cmd, "\n";
2852 redo CMD;
2853 };
69893cff
RGS
2854
2855=head4 C<$sh> - Invoke a shell
2856
2857Uses C<DB::system> to invoke a shell.
2858
2859=cut
2860
2861 # $sh - start a shell.
e22ea7cc
RF
2862 $cmd =~ /^$sh$/ && do {
2863
69893cff
RGS
2864 # Run the user's shell. If none defined, run Bourne.
2865 # We resume execution when the shell terminates.
e22ea7cc
RF
2866 &system( $ENV{SHELL} || "/bin/sh" );
2867 next CMD;
2868 };
69893cff
RGS
2869
2870=head4 C<$sh I<command>> - Force execution of a command in a shell
2871
2872Like the above, but the command is passed to the shell. Again, we use
2873C<DB::system> to avoid problems with C<STDIN> and C<STDOUT>.
2874
2875=cut
2876
2877 # $sh command - start a shell and run a command in it.
e22ea7cc
RF
2878 $cmd =~ /^$sh\s*([\x00-\xff]*)/ && do {
2879
2880 # XXX: using csh or tcsh destroys sigint retvals!
2881 #&system($1); # use this instead
69893cff
RGS
2882
2883 # use the user's shell, or Bourne if none defined.
e22ea7cc
RF
2884 &system( $ENV{SHELL} || "/bin/sh", "-c", $1 );
2885 next CMD;
2886 };
69893cff
RGS
2887
2888=head4 C<H> - display commands in history
2889
2890Prints the contents of C<@hist> (if any).
2891
2892=cut
2893
7fddc82f
RF
2894 $cmd =~ /^H\b\s*\*/ && do {
2895 @hist = @truehist = ();
2896 print $OUT "History cleansed\n";
2897 next CMD;
2898 };
e22ea7cc
RF
2899
2900 $cmd =~ /^H\b\s*(-(\d+))?/ && do {
2901
2902 # Anything other than negative numbers is ignored by
69893cff 2903 # the (incorrect) pattern, so this test does nothing.
e22ea7cc 2904 $end = $2 ? ( $#hist - $2 ) : 0;
69893cff
RGS
2905
2906 # Set to the minimum if less than zero.
e22ea7cc 2907 $hist = 0 if $hist < 0;
69893cff 2908
e22ea7cc 2909 # Start at the end of the array.
69893cff
RGS
2910 # Stay in while we're still above the ending value.
2911 # Tick back by one each time around the loop.
e22ea7cc 2912 for ( $i = $#hist ; $i > $end ; $i-- ) {
69893cff
RGS
2913
2914 # Print the command unless it has no arguments.
e22ea7cc
RF
2915 print $OUT "$i: ", $hist[$i], "\n"
2916 unless $hist[$i] =~ /^.?$/;
2917 }
2918 next CMD;
2919 };
69893cff
RGS
2920
2921=head4 C<man, doc, perldoc> - look up documentation
2922
2923Just calls C<runman()> to print the appropriate document.
2924
2925=cut
2926
e22ea7cc
RF
2927 # man, perldoc, doc - show manual pages.
2928 $cmd =~ /^(?:man|(?:perl)?doc)\b(?:\s+([^(]*))?$/ && do {
2929 runman($1);
2930 next CMD;
2931 };
69893cff
RGS
2932
2933=head4 C<p> - print
2934
2935Builds a C<print EXPR> expression in the C<$cmd>; this will get executed at
2936the bottom of the loop.
2937
2938=cut
2939
2940 # p - print (no args): print $_.
e22ea7cc 2941 $cmd =~ s/^p$/print {\$DB::OUT} \$_/;
69893cff
RGS
2942
2943 # p - print the given expression.
e22ea7cc 2944 $cmd =~ s/^p\b/print {\$DB::OUT} /;
69893cff
RGS
2945
2946=head4 C<=> - define command alias
2947
2948Manipulates C<%alias> to add or list command aliases.
2949
2950=cut
2951
e22ea7cc
RF
2952 # = - set up a command alias.
2953 $cmd =~ s/^=\s*// && do {
2954 my @keys;
2955 if ( length $cmd == 0 ) {
2956
69893cff 2957 # No args, get current aliases.
e22ea7cc
RF
2958 @keys = sort keys %alias;
2959 }
2960 elsif ( my ( $k, $v ) = ( $cmd =~ /^(\S+)\s+(\S.*)/ ) ) {
2961
69893cff
RGS
2962 # Creating a new alias. $k is alias name, $v is
2963 # alias value.
2964
e22ea7cc
RF
2965 # can't use $_ or kill //g state
2966 for my $x ( $k, $v ) {
2967
2968 # Escape "alarm" characters.
2969 $x =~ s/\a/\\a/g;
2970 }
69893cff
RGS
2971
2972 # Substitute key for value, using alarm chars
e22ea7cc 2973 # as separators (which is why we escaped them in
69893cff 2974 # the command).
e22ea7cc 2975 $alias{$k} = "s\a$k\a$v\a";
69893cff
RGS
2976
2977 # Turn off standard warn and die behavior.
e22ea7cc
RF
2978 local $SIG{__DIE__};
2979 local $SIG{__WARN__};
69893cff
RGS
2980
2981 # Is it valid Perl?
e22ea7cc
RF
2982 unless ( eval "sub { s\a$k\a$v\a }; 1" ) {
2983
69893cff 2984 # Nope. Bad alias. Say so and get out.
e22ea7cc
RF
2985 print $OUT "Can't alias $k to $v: $@\n";
2986 delete $alias{$k};
2987 next CMD;
2988 }
2989
69893cff 2990 # We'll only list the new one.
e22ea7cc 2991 @keys = ($k);
69893cff
RGS
2992 } ## end elsif (my ($k, $v) = ($cmd...
2993
2994 # The argument is the alias to list.
e22ea7cc
RF
2995 else {
2996 @keys = ($cmd);
2997 }
69893cff
RGS
2998
2999 # List aliases.
e22ea7cc
RF
3000 for my $k (@keys) {
3001
98dc9551 3002 # Messy metaquoting: Trim the substitution code off.
69893cff
RGS
3003 # We use control-G as the delimiter because it's not
3004 # likely to appear in the alias.
e22ea7cc
RF
3005 if ( ( my $v = $alias{$k} ) =~ s\as\a$k\a(.*)\a$\a1\a ) {
3006
69893cff 3007 # Print the alias.
e22ea7cc
RF
3008 print $OUT "$k\t= $1\n";
3009 }
3010 elsif ( defined $alias{$k} ) {
3011
69893cff 3012 # Couldn't trim it off; just print the alias code.
e22ea7cc
RF
3013 print $OUT "$k\t$alias{$k}\n";
3014 }
3015 else {
3016
69893cff 3017 # No such, dude.
e22ea7cc
RF
3018 print "No alias for $k\n";
3019 }
69893cff 3020 } ## end for my $k (@keys)
e22ea7cc
RF
3021 next CMD;
3022 };
69893cff
RGS
3023
3024=head4 C<source> - read commands from a file.
3025
3026Opens a lexical filehandle and stacks it on C<@cmdfhs>; C<DB::readline> will
3027pick it up.
3028
3029=cut
3030
e22ea7cc
RF
3031 # source - read commands from a file (or pipe!) and execute.
3032 $cmd =~ /^source\s+(.*\S)/ && do {
3033 if ( open my $fh, $1 ) {
3034
69893cff 3035 # Opened OK; stick it in the list of file handles.
e22ea7cc
RF
3036 push @cmdfhs, $fh;
3037 }
3038 else {
3039
3040 # Couldn't open it.
1f874cb6 3041 &warn("Can't execute '$1': $!\n");
e22ea7cc
RF
3042 }
3043 next CMD;
3044 };
69893cff 3045
e09195af
SF
3046 $cmd =~ /^(enable|disable)\s+(\S+)\s*$/ && do {
3047 my ($cmd, $position) = ($1, $2);
3048
3049 my ($fn, $line_num);
3050 if ($position =~ m{\A\d+\z})
3051 {
3052 $fn = $filename;
3053 $line_num = $position;
3054 }
3055 elsif ($position =~ m{\A(.*):(\d+)\z})
3056 {
3057 ($fn, $line_num) = ($1, $2);
3058 }
3059 else
3060 {
3061 &warn("Wrong spec for enable/disable argument.\n");
3062 }
3063
3064 if (defined($fn)) {
3065 if (_has_breakpoint_data_ref($fn, $line_num)) {
3066 _set_breakpoint_enabled_status($fn, $line_num,
3067 ($cmd eq 'enable' ? 1 : '')
3068 );
3069 }
3070 else {
3071 &warn("No breakpoint set at ${fn}:${line_num}\n");
3072 }
3073 }
3074
3075 next CMD;
3076 };
3077
69893cff
RGS
3078=head4 C<save> - send current history to a file
3079
3080Takes the complete history, (not the shrunken version you see with C<H>),
3081and saves it to the given filename, so it can be replayed using C<source>.
3082
3083Note that all C<^(save|source)>'s are commented out with a view to minimise recursion.
3084
3085=cut
3086
3087 # save source - write commands to a file for later use
3088 $cmd =~ /^save\s*(.*)$/ && do {
e22ea7cc
RF
3089 my $file = $1 || '.perl5dbrc'; # default?
3090 if ( open my $fh, "> $file" ) {
3091
3092 # chomp to remove extraneous newlines from source'd files
3093 chomp( my @truelist =
3094 map { m/^\s*(save|source)/ ? "#$_" : $_ }
3095 @truehist );
3096 print $fh join( "\n", @truelist );
69893cff 3097 print "commands saved in $file\n";
e22ea7cc
RF
3098 }
3099 else {
69893cff
RGS
3100 &warn("Can't save debugger commands in '$1': $!\n");
3101 }
3102 next CMD;
3103 };
3104
7fddc82f
RF
3105=head4 C<R> - restart
3106
3107Restart the debugger session.
3108
3109=head4 C<rerun> - rerun the current session
3110
3111Return to any given position in the B<true>-history list
3112
3113=cut
3114
3115 # R - restart execution.
3116 # rerun - controlled restart execution.
3117 $cmd =~ /^(R|rerun\s*(.*))$/ && do {
3118 my @args = ($1 eq 'R' ? restart() : rerun($2));
3119
ca28b541
AP
3120 # Close all non-system fds for a clean restart. A more
3121 # correct method would be to close all fds that were not
3122 # open when the process started, but this seems to be
3123 # hard. See "debugger 'R'estart and open database
3124 # connections" on p5p.
3125
47d3bbda 3126 my $max_fd = 1024; # default if POSIX can't be loaded
ca28b541 3127 if (eval { require POSIX }) {
5332cc68 3128 eval { $max_fd = POSIX::sysconf(POSIX::_SC_OPEN_MAX()) };
ca28b541
AP
3129 }
3130
3131 if (defined $max_fd) {
3132 foreach ($^F+1 .. $max_fd-1) {
3133 next unless open FD_TO_CLOSE, "<&=$_";
3134 close(FD_TO_CLOSE);
3135 }
3136 }
3137
7fddc82f
RF
3138 # And run Perl again. We use exec() to keep the
3139 # PID stable (and that way $ini_pids is still valid).
3140 exec(@args) || print $OUT "exec failed: $!\n";
3141
3142 last CMD;
3143 };
3144
69893cff
RGS
3145=head4 C<|, ||> - pipe output through the pager.
3146
be9a9b1d 3147For C<|>, we save C<OUT> (the debugger's output filehandle) and C<STDOUT>
69893cff
RGS
3148(the program's standard output). For C<||>, we only save C<OUT>. We open a
3149pipe to the pager (restoring the output filehandles if this fails). If this
3150is the C<|> command, we also set up a C<SIGPIPE> handler which will simply
3151set C<$signal>, sending us back into the debugger.
3152
3153We then trim off the pipe symbols and C<redo> the command loop at the
3154C<PIPE> label, causing us to evaluate the command in C<$cmd> without
3155reading another.
3156
3157=cut
3158
3159 # || - run command in the pager, with output to DB::OUT.
e22ea7cc
RF
3160 $cmd =~ /^\|\|?\s*[^|]/ && do {
3161 if ( $pager =~ /^\|/ ) {
3162
69893cff 3163 # Default pager is into a pipe. Redirect I/O.
e22ea7cc
RF
3164 open( SAVEOUT, ">&STDOUT" )
3165 || &warn("Can't save STDOUT");
3166 open( STDOUT, ">&OUT" )
3167 || &warn("Can't redirect STDOUT");
69893cff 3168 } ## end if ($pager =~ /^\|/)
e22ea7cc
RF
3169 else {
3170
69893cff 3171 # Not into a pipe. STDOUT is safe.
e22ea7cc
RF
3172 open( SAVEOUT, ">&OUT" ) || &warn("Can't save DB::OUT");
3173 }
69893cff
RGS
3174
3175 # Fix up environment to record we have less if so.
e22ea7cc
RF
3176 fix_less();
3177
3178 unless ( $piped = open( OUT, $pager ) ) {
69893cff 3179
69893cff 3180 # Couldn't open pipe to pager.
1f874cb6 3181 &warn("Can't pipe output to '$pager'");
e22ea7cc
RF
3182 if ( $pager =~ /^\|/ ) {
3183
69893cff 3184 # Redirect I/O back again.
e22ea7cc
RF
3185 open( OUT, ">&STDOUT" ) # XXX: lost message
3186 || &warn("Can't restore DB::OUT");
3187 open( STDOUT, ">&SAVEOUT" )
3188 || &warn("Can't restore STDOUT");
3189 close(SAVEOUT);
69893cff 3190 } ## end if ($pager =~ /^\|/)
e22ea7cc
RF
3191 else {
3192
69893cff 3193 # Redirect I/O. STDOUT already safe.
e22ea7cc
RF
3194 open( OUT, ">&STDOUT" ) # XXX: lost message
3195 || &warn("Can't restore DB::OUT");
3196 }
3197 next CMD;
69893cff
RGS
3198 } ## end unless ($piped = open(OUT,...
3199
3200 # Set up broken-pipe handler if necessary.
e22ea7cc
RF
3201 $SIG{PIPE} = \&DB::catch
3202 if $pager =~ /^\|/
3203 && ( "" eq $SIG{PIPE} || "DEFAULT" eq $SIG{PIPE} );
69893cff
RGS
3204
3205 # Save current filehandle, unbuffer out, and put it back.
e22ea7cc
RF
3206 $selected = select(OUT);
3207 $| = 1;
69893cff
RGS
3208
3209 # Don't put it back if pager was a pipe.
e22ea7cc 3210 select($selected), $selected = "" unless $cmd =~ /^\|\|/;
69893cff
RGS
3211
3212 # Trim off the pipe symbols and run the command now.
e22ea7cc
RF
3213 $cmd =~ s/^\|+\s*//;
3214 redo PIPE;
3215 };
69893cff
RGS
3216
3217=head3 END OF COMMAND PARSING
3218
3219Anything left in C<$cmd> at this point is a Perl expression that we want to
3220evaluate. We'll always evaluate in the user's context, and fully qualify
3221any variables we might want to address in the C<DB> package.
3222
3223=cut
3224
3225 # t - turn trace on.
611272bb
PS
3226 $cmd =~ s/^t\s+(\d+)?/\$DB::trace |= 1;\n/ && do {
3227 $trace_to_depth = $1 ? $stack_depth||0 + $1 : 1E9;
3228 };
69893cff
RGS
3229
3230 # s - single-step. Remember the last command was 's'.
e22ea7cc 3231 $cmd =~ s/^s\s/\$DB::single = 1;\n/ && do { $laststep = 's' };
69893cff
RGS
3232
3233 # n - single-step, but not into subs. Remember last command
e22ea7cc
RF
3234 # was 'n'.
3235 $cmd =~ s/^n\s/\$DB::single = 2;\n/ && do { $laststep = 'n' };
69893cff 3236
e22ea7cc 3237 } # PIPE:
69893cff 3238
e22ea7cc 3239 # Make sure the flag that says "the debugger's running" is
69893cff 3240 # still on, to make sure we get control again.
e22ea7cc 3241 $evalarg = "\$^D = \$^D | \$DB::db_stop;\n$cmd";
69893cff
RGS
3242
3243 # Run *our* eval that executes in the caller's context.
e22ea7cc 3244 &eval;
69893cff
RGS
3245
3246 # Turn off the one-time-dump stuff now.
e22ea7cc
RF
3247 if ($onetimeDump) {
3248 $onetimeDump = undef;
69893cff 3249 $onetimedumpDepth = undef;
e22ea7cc
RF
3250 }
3251 elsif ( $term_pid == $$ ) {
c7e68384
IZ
3252 eval { # May run under miniperl, when not available...
3253 STDOUT->flush();
3254 STDERR->flush();
3255 };
e22ea7cc 3256
69893cff 3257 # XXX If this is the master pid, print a newline.
e22ea7cc
RF
3258 print $OUT "\n";
3259 }
3260 } ## end while (($term || &setterm...
69893cff
RGS
3261
3262=head3 POST-COMMAND PROCESSING
3263
3264After each command, we check to see if the command output was piped anywhere.
3265If so, we go through the necessary code to unhook the pipe and go back to
3266our standard filehandles for input and output.
3267
3268=cut
3269
e22ea7cc 3270 continue { # CMD:
69893cff
RGS
3271
3272 # At the end of every command:
e22ea7cc
RF
3273 if ($piped) {
3274
69893cff 3275 # Unhook the pipe mechanism now.
e22ea7cc
RF
3276 if ( $pager =~ /^\|/ ) {
3277
69893cff 3278 # No error from the child.
e22ea7cc 3279 $? = 0;
69893cff 3280
e22ea7cc
RF
3281 # we cannot warn here: the handle is missing --tchrist
3282 close(OUT) || print SAVEOUT "\nCan't close DB::OUT\n";
69893cff 3283
e22ea7cc 3284 # most of the $? crud was coping with broken cshisms
69893cff 3285 # $? is explicitly set to 0, so this never runs.
e22ea7cc 3286 if ($?) {
1f874cb6 3287 print SAVEOUT "Pager '$pager' failed: ";
e22ea7cc
RF
3288 if ( $? == -1 ) {
3289 print SAVEOUT "shell returned -1\n";
3290 }
3291 elsif ( $? >> 8 ) {
3292 print SAVEOUT ( $? & 127 )
3293 ? " (SIG#" . ( $? & 127 ) . ")"
3294 : "", ( $? & 128 ) ? " -- core dumped" : "", "\n";
3295 }
3296 else {
3297 print SAVEOUT "status ", ( $? >> 8 ), "\n";
3298 }
69893cff
RGS
3299 } ## end if ($?)
3300
e22ea7cc 3301 # Reopen filehandle for our output (if we can) and
69893cff 3302 # restore STDOUT (if we can).
e22ea7cc
RF
3303 open( OUT, ">&STDOUT" ) || &warn("Can't restore DB::OUT");
3304 open( STDOUT, ">&SAVEOUT" )
3305 || &warn("Can't restore STDOUT");
69893cff
RGS
3306
3307 # Turn off pipe exception handler if necessary.
e22ea7cc 3308 $SIG{PIPE} = "DEFAULT" if $SIG{PIPE} eq \&DB::catch;
69893cff 3309
e22ea7cc
RF
3310 # Will stop ignoring SIGPIPE if done like nohup(1)
3311 # does SIGINT but Perl doesn't give us a choice.
69893cff 3312 } ## end if ($pager =~ /^\|/)
e22ea7cc
RF
3313 else {
3314
69893cff 3315 # Non-piped "pager". Just restore STDOUT.
e22ea7cc
RF
3316 open( OUT, ">&SAVEOUT" ) || &warn("Can't restore DB::OUT");
3317 }
69893cff
RGS
3318
3319 # Close filehandle pager was using, restore the normal one
3320 # if necessary,
3321 close(SAVEOUT);
e22ea7cc 3322 select($selected), $selected = "" unless $selected eq "";
69893cff
RGS
3323
3324 # No pipes now.
e22ea7cc 3325 $piped = "";
69893cff 3326 } ## end if ($piped)
e22ea7cc 3327 } # CMD:
69893cff
RGS
3328
3329=head3 COMMAND LOOP TERMINATION
3330
3331When commands have finished executing, we come here. If the user closed the
3332input filehandle, we turn on C<$fall_off_end> to emulate a C<q> command. We
3333evaluate any post-prompt items. We restore C<$@>, C<$!>, C<$^E>, C<$,>, C<$/>,
3334C<$\>, and C<$^W>, and return a null list as expected by the Perl interpreter.
3335The interpreter will then execute the next line and then return control to us
3336again.
3337
3338=cut
3339
3340 # No more commands? Quit.
1f874cb6 3341 $fall_off_end = 1 unless defined $cmd; # Emulate 'q' on EOF
69893cff
RGS
3342
3343 # Evaluate post-prompt commands.
e22ea7cc
RF
3344 foreach $evalarg (@$post) {
3345 &eval;
3346 }
3347 } # if ($single || $signal)
69893cff
RGS
3348
3349 # Put the user's globals back where you found them.
e22ea7cc 3350 ( $@, $!, $^E, $,, $/, $\, $^W ) = @saved;
69893cff
RGS
3351 ();
3352} ## end sub DB
3353
3354# The following code may be executed now:
3355# BEGIN {warn 4}
3356
3357=head2 sub
3358
3359C<sub> is called whenever a subroutine call happens in the program being
3360debugged. The variable C<$DB::sub> contains the name of the subroutine
3361being called.
3362
3363The core function of this subroutine is to actually call the sub in the proper
3364context, capturing its output. This of course causes C<DB::DB> to get called
3365again, repeating until the subroutine ends and returns control to C<DB::sub>
3366again. Once control returns, C<DB::sub> figures out whether or not to dump the
3367return value, and returns its captured copy of the return value as its own
3368return value. The value then feeds back into the program being debugged as if
3369C<DB::sub> hadn't been there at all.
3370
3371C<sub> does all the work of printing the subroutine entry and exit messages
3372enabled by setting C<$frame>. It notes what sub the autoloader got called for,
3373and also prints the return value if needed (for the C<r> command and if
3374the 16 bit is set in C<$frame>).
3375
3376It also tracks the subroutine call depth by saving the current setting of
3377C<$single> in the C<@stack> package global; if this exceeds the value in
3378C<$deep>, C<sub> automatically turns on printing of the current depth by
be9a9b1d 3379setting the C<4> bit in C<$single>. In any case, it keeps the current setting
69893cff
RGS
3380of stop/don't stop on entry to subs set as it currently is set.
3381
3382=head3 C<caller()> support
3383
3384If C<caller()> is called from the package C<DB>, it provides some
3385additional data, in the following order:
3386
3387=over 4
3388
3389=item * C<$package>
3390
3391The package name the sub was in
3392
3393=item * C<$filename>
3394
3395The filename it was defined in
3396
3397=item * C<$line>
3398
3399The line number it was defined on
3400
3401=item * C<$subroutine>
3402
be9a9b1d 3403The subroutine name; C<(eval)> if an C<eval>().
69893cff
RGS
3404
3405=item * C<$hasargs>
3406
34071 if it has arguments, 0 if not
3408
3409=item * C<$wantarray>
3410
34111 if array context, 0 if scalar context
3412
3413=item * C<$evaltext>
3414
3415The C<eval>() text, if any (undefined for C<eval BLOCK>)
3416
3417=item * C<$is_require>
3418
3419frame was created by a C<use> or C<require> statement
3420
3421=item * C<$hints>
3422
3423pragma information; subject to change between versions
3424
3425=item * C<$bitmask>
3426
be9a9b1d 3427pragma information; subject to change between versions
69893cff
RGS
3428
3429=item * C<@DB::args>
3430
3431arguments with which the subroutine was invoked
3432
3433=back
3434
3435=cut
d338d6fe 3436
d12a4851 3437sub sub {
b7bfa855
B
3438 # Do not use a regex in this subroutine -> results in corrupted memory
3439 # See: [perl #66110]
69893cff 3440
2cbb2ee1
RGS
3441 # lock ourselves under threads
3442 lock($DBGR);
3443
69893cff
RGS
3444 # Whether or not the autoloader was running, a scalar to put the
3445 # sub's return value in (if needed), and an array to put the sub's
3446 # return value in (if needed).
e22ea7cc 3447 my ( $al, $ret, @ret ) = "";
b7bfa855 3448 if ($sub eq 'threads::new' && $ENV{PERL5DB_THREADED}) {
2cbb2ee1
RGS
3449 print "creating new thread\n";
3450 }
69893cff 3451
c81c05fc 3452 # If the last ten characters are '::AUTOLOAD', note we've traced
69893cff 3453 # into AUTOLOAD for $sub.
e22ea7cc 3454 if ( length($sub) > 10 && substr( $sub, -10, 10 ) eq '::AUTOLOAD' ) {
c81c05fc 3455 $al = " for $$sub" if defined $$sub;
d12a4851 3456 }
69893cff
RGS
3457
3458 # We stack the stack pointer and then increment it to protect us
3459 # from a situation that might unwind a whole bunch of call frames
3460 # at once. Localizing the stack pointer means that it will automatically
3461 # unwind the same amount when multiple stack frames are unwound.
e22ea7cc 3462 local $stack_depth = $stack_depth + 1; # Protect from non-local exits
69893cff
RGS
3463
3464 # Expand @stack.
d12a4851 3465 $#stack = $stack_depth;
69893cff
RGS
3466
3467 # Save current single-step setting.
d12a4851 3468 $stack[-1] = $single;
69893cff 3469
e22ea7cc 3470 # Turn off all flags except single-stepping.
d12a4851 3471 $single &= 1;
69893cff
RGS
3472
3473 # If we've gotten really deeply recursed, turn on the flag that will
3474 # make us stop with the 'deep recursion' message.
d12a4851 3475 $single |= 4 if $stack_depth == $deep;
69893cff
RGS
3476
3477 # If frame messages are on ...
3478 (
3479 $frame & 4 # Extended frame entry message
e22ea7cc
RF
3480 ? (
3481 print_lineinfo( ' ' x ( $stack_depth - 1 ), "in " ),
69893cff 3482
e22ea7cc 3483 # Why -1? But it works! :-(
69893cff
RGS
3484 # Because print_trace will call add 1 to it and then call
3485 # dump_trace; this results in our skipping -1+1 = 0 stack frames
3486 # in dump_trace.
e22ea7cc
RF
3487 print_trace( $LINEINFO, -1, 1, 1, "$sub$al" )
3488 )
3489 : print_lineinfo( ' ' x ( $stack_depth - 1 ), "entering $sub$al\n" )
3490
69893cff 3491 # standard frame entry message
e22ea7cc
RF
3492 )
3493 if $frame;
69893cff 3494
98dc9551 3495 # Determine the sub's return type, and capture appropriately.
d12a4851 3496 if (wantarray) {
e22ea7cc 3497
69893cff
RGS
3498 # Called in array context. call sub and capture output.
3499 # DB::DB will recursively get control again if appropriate; we'll come
3500 # back here when the sub is finished.
584420f0 3501 @ret = &$sub;
69893cff
RGS
3502
3503 # Pop the single-step value back off the stack.
e22ea7cc 3504 $single |= $stack[ $stack_depth-- ];
69893cff
RGS
3505
3506 # Check for exit trace messages...
e22ea7cc
RF
3507 (
3508 $frame & 4 # Extended exit message
3509 ? (
3510 print_lineinfo( ' ' x $stack_depth, "out " ),
3511 print_trace( $LINEINFO, -1, 1, 1, "$sub$al" )
3512 )
3513 : print_lineinfo( ' ' x $stack_depth, "exited $sub$al\n" )
3514
69893cff 3515 # Standard exit message
e22ea7cc
RF
3516 )
3517 if $frame & 2;
69893cff
RGS
3518
3519 # Print the return info if we need to.
e22ea7cc
RF
3520 if ( $doret eq $stack_depth or $frame & 16 ) {
3521
69893cff 3522 # Turn off output record separator.
e22ea7cc
RF
3523 local $\ = '';
3524 my $fh = ( $doret eq $stack_depth ? $OUT : $LINEINFO );
69893cff
RGS
3525
3526 # Indent if we're printing because of $frame tracing.
e22ea7cc 3527 print $fh ' ' x $stack_depth if $frame & 16;
69893cff
RGS
3528
3529 # Print the return value.
e22ea7cc
RF
3530 print $fh "list context return from $sub:\n";
3531 dumpit( $fh, \@ret );
69893cff
RGS
3532
3533 # And don't print it again.
e22ea7cc 3534 $doret = -2;
69893cff 3535 } ## end if ($doret eq $stack_depth...
e22ea7cc
RF
3536 # And we have to return the return value now.
3537 @ret;
69893cff
RGS
3538 } ## end if (wantarray)
3539
3540 # Scalar context.
3541 else {
584420f0 3542 if ( defined wantarray ) {
e22ea7cc 3543
584420f0
RGS
3544 # Save the value if it's wanted at all.
3545 $ret = &$sub;
3546 }
3547 else {
e22ea7cc 3548
584420f0
RGS
3549 # Void return, explicitly.
3550 &$sub;
3551 undef $ret;
3552 }
69893cff
RGS
3553
3554 # Pop the single-step value off the stack.
e22ea7cc 3555 $single |= $stack[ $stack_depth-- ];
69893cff
RGS
3556
3557 # If we're doing exit messages...
e22ea7cc 3558 (
98dc9551 3559 $frame & 4 # Extended messages
e22ea7cc
RF
3560 ? (
3561 print_lineinfo( ' ' x $stack_depth, "out " ),
3562 print_trace( $LINEINFO, -1, 1, 1, "$sub$al" )
3563 )
3564 : print_lineinfo( ' ' x $stack_depth, "exited $sub$al\n" )
3565
3566 # Standard messages
3567 )
3568 if $frame & 2;
69893cff
RGS
3569
3570 # If we are supposed to show the return value... same as before.
e22ea7cc
RF
3571 if ( $doret eq $stack_depth or $frame & 16 and defined wantarray ) {
3572 local $\ = '';
3573 my $fh = ( $doret eq $stack_depth ? $OUT : $LINEINFO );
3574 print $fh ( ' ' x $stack_depth ) if $frame & 16;
3575 print $fh (
3576 defined wantarray
3577 ? "scalar context return from $sub: "
3578 : "void context return from $sub\n"
3579 );
3580 dumpit( $fh, $ret ) if defined wantarray;
3581 $doret = -2;
69893cff
RGS
3582 } ## end if ($doret eq $stack_depth...
3583
3584 # Return the appropriate scalar value.
e22ea7cc 3585 $ret;
69893cff
RGS
3586 } ## end else [ if (wantarray)
3587} ## end sub sub
3588
89d1f0ef
SP
3589sub lsub : lvalue {
3590
3591 # lock ourselves under threads
3592 lock($DBGR);
3593
3594 # Whether or not the autoloader was running, a scalar to put the
3595 # sub's return value in (if needed), and an array to put the sub's
3596 # return value in (if needed).
3597 my ( $al, $ret, @ret ) = "";
3598 if ($sub =~ /^threads::new$/ && $ENV{PERL5DB_THREADED}) {
3599 print "creating new thread\n";
3600 }
3601
3602 # If the last ten characters are C'::AUTOLOAD', note we've traced
3603 # into AUTOLOAD for $sub.
3604 if ( length($sub) > 10 && substr( $sub, -10, 10 ) eq '::AUTOLOAD' ) {
3605 $al = " for $$sub";
3606 }
3607
3608 # We stack the stack pointer and then increment it to protect us
3609 # from a situation that might unwind a whole bunch of call frames
3610 # at once. Localizing the stack pointer means that it will automatically
3611 # unwind the same amount when multiple stack frames are unwound.
3612 local $stack_depth = $stack_depth + 1; # Protect from non-local exits
3613
3614 # Expand @stack.
3615 $#stack = $stack_depth;
3616
3617 # Save current single-step setting.
3618 $stack[-1] = $single;
3619
3620 # Turn off all flags except single-stepping.
3621 $single &= 1;
3622
3623 # If we've gotten really deeply recursed, turn on the flag that will
3624 # make us stop with the 'deep recursion' message.
3625 $single |= 4 if $stack_depth == $deep;
3626
3627 # If frame messages are on ...
3628 (
3629 $frame & 4 # Extended frame entry message
3630 ? (
3631 print_lineinfo( ' ' x ( $stack_depth - 1 ), "in " ),
3632
3633 # Why -1? But it works! :-(
3634 # Because print_trace will call add 1 to it and then call
3635 # dump_trace; this results in our skipping -1+1 = 0 stack frames
3636 # in dump_trace.
3637 print_trace( $LINEINFO, -1, 1, 1, "$sub$al" )
3638 )
3639 : print_lineinfo( ' ' x ( $stack_depth - 1 ), "entering $sub$al\n" )
3640
3641 # standard frame entry message
3642 )
3643 if $frame;
3644
3645 # Pop the single-step value back off the stack.
3646 $single |= $stack[ $stack_depth-- ];
3647
3648 # call the original lvalue sub.
3649 &$sub;
3650}
3651
611272bb
PS
3652# Abstracting common code from multiple places elsewhere:
3653sub depth_print_lineinfo {
8dc67a69
SF
3654 my $always_print = shift;
3655
3656 print_lineinfo( @_ ) if ($always_print or $stack_depth < $trace_to_depth);
611272bb
PS
3657}
3658
69893cff
RGS
3659=head1 EXTENDED COMMAND HANDLING AND THE COMMAND API
3660
3661In Perl 5.8.0, there was a major realignment of the commands and what they did,
3662Most of the changes were to systematize the command structure and to eliminate
3663commands that threw away user input without checking.
3664
3665The following sections describe the code added to make it easy to support
3666multiple command sets with conflicting command names. This section is a start
3667at unifying all command processing to make it simpler to develop commands.
3668
3669Note that all the cmd_[a-zA-Z] subroutines require the command name, a line
3670number, and C<$dbline> (the current line) as arguments.
3671
3672Support functions in this section which have multiple modes of failure C<die>
3673on error; the rest simply return a false value.
3674
3675The user-interface functions (all of the C<cmd_*> functions) just output
3676error messages.
3677
3678=head2 C<%set>
3679
3680The C<%set> hash defines the mapping from command letter to subroutine
3681name suffix.
3682
3683C<%set> is a two-level hash, indexed by set name and then by command name.
be9a9b1d
AT
3684Note that trying to set the CommandSet to C<foobar> simply results in the
36855.8.0 command set being used, since there's no top-level entry for C<foobar>.
69893cff
RGS
3686
3687=cut
d338d6fe 3688
d12a4851 3689### The API section
f1583d8f 3690
e22ea7cc
RF
3691my %set = ( #
3692 'pre580' => {
3693 'a' => 'pre580_a',
3694 'A' => 'pre580_null',
3695 'b' => 'pre580_b',
3696</