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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 $filename for C<eval>ed strings looks
192like C<(eval 34)> or C<(re_eval 19)>.
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193
194=head1 DEBUGGER STARTUP
195
196When C<perl5db.pl> starts, it reads an rcfile (C<perl5db.ini> for
197non-interactive sessions, C<.perldb> for interactive ones) that can set a number
198of options. In addition, this file may define a subroutine C<&afterinit>
199that will be executed (in the debugger's context) after the debugger has
200initialized itself.
201
202Next, it checks the C<PERLDB_OPTS> environment variable and treats its
be9a9b1d 203contents as the argument of a C<o> command in the debugger.
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204
205=head2 STARTUP-ONLY OPTIONS
206
207The following options can only be specified at startup.
208To set them in your rcfile, add a call to
209C<&parse_options("optionName=new_value")>.
210
211=over 4
212
213=item * TTY
214
215the TTY to use for debugging i/o.
216
217=item * noTTY
218
219if set, goes in NonStop mode. On interrupt, if TTY is not set,
b0e77abc 220uses the value of noTTY or F<$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:
5d104d50 522$VERSION = '1.34';
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 ;-)
715
69893cff
RGS
716# (We have made efforts to clarify the comments in the change log
717# in other places; some of them may seem somewhat obscure as they
718# were originally written, and explaining them away from the code
719# in question seems conterproductive.. -JM)
720
721########################################################################
722# Changes: 0.94
723# + A lot of things changed after 0.94. First of all, core now informs
724# debugger about entry into XSUBs, overloaded operators, tied operations,
1f874cb6 725# BEGIN and END. Handy with 'O f=2'.
69893cff
RGS
726# + This can make debugger a little bit too verbose, please be patient
727# and report your problems promptly.
728# + Now the option frame has 3 values: 0,1,2. XXX Document!
729# + Note that if DESTROY returns a reference to the object (or object),
730# the deletion of data may be postponed until the next function call,
731# due to the need to examine the return value.
732#
733# Changes: 0.95
1f874cb6 734# + 'v' command shows versions.
69893cff 735#
e22ea7cc 736# Changes: 0.96
1f874cb6
JK
737# + 'v' command shows version of readline.
738# primitive completion works (dynamic variables, subs for 'b' and 'l',
739# options). Can 'p %var'
740# + Better help ('h <' now works). New commands <<, >>, {, {{.
69893cff 741# {dump|print}_trace() coded (to be able to do it from <<cmd).
1f874cb6 742# + 'c sub' documented.
69893cff
RGS
743# + At last enough magic combined to stop after the end of debuggee.
744# + !! should work now (thanks to Emacs bracket matching an extra
1f874cb6
JK
745# ']' in a regexp is caught).
746# + 'L', 'D' and 'A' span files now (as documented).
747# + Breakpoints in 'require'd code are possible (used in 'R').
69893cff 748# + Some additional words on internal work of debugger.
1f874cb6
JK
749# + 'b load filename' implemented.
750# + 'b postpone subr' implemented.
751# + now only 'q' exits debugger (overwritable on $inhibit_exit).
69893cff 752# + When restarting debugger breakpoints/actions persist.
e22ea7cc 753# + Buglet: When restarting debugger only one breakpoint/action per
69893cff
RGS
754# autoloaded function persists.
755#
36477c24 756# Changes: 0.97: NonStop will not stop in at_exit().
69893cff
RGS
757# + Option AutoTrace implemented.
758# + Trace printed differently if frames are printed too.
1f874cb6 759# + new 'inhibitExit' option.
69893cff 760# + printing of a very long statement interruptible.
1f874cb6
JK
761# Changes: 0.98: New command 'm' for printing possible methods
762# + 'l -' is a synonym for '-'.
69893cff 763# + Cosmetic bugs in printing stack trace.
1f874cb6 764# + 'frame' & 8 to print "expanded args" in stack trace.
69893cff 765# + Can list/break in imported subs.
1f874cb6 766# + new 'maxTraceLen' option.
69893cff 767# + frame & 4 and frame & 8 granted.
1f874cb6
JK
768# + new command 'm'
769# + nonstoppable lines do not have ':' near the line number.
770# + 'b compile subname' implemented.
69893cff 771# + Will not use $` any more.
1f874cb6
JK
772# + '-' behaves sane now.
773# Changes: 0.99: Completion for 'f', 'm'.
774# + 'm' will remove duplicate names instead of duplicate functions.
775# + 'b load' strips trailing whitespace.
776# completion ignores leading '|'; takes into account current package
777# when completing a subroutine name (same for 'l').
055fd3a9
GS
778# Changes: 1.07: Many fixed by tchrist 13-March-2000
779# BUG FIXES:
04e43a21 780# + Added bare minimal security checks on perldb rc files, plus
055fd3a9
GS
781# comments on what else is needed.
782# + Fixed the ornaments that made "|h" completely unusable.
783# They are not used in print_help if they will hurt. Strip pod
784# if we're paging to less.
785# + Fixed mis-formatting of help messages caused by ornaments
e22ea7cc
RF
786# to restore Larry's original formatting.
787# + Fixed many other formatting errors. The code is still suboptimal,
04e43a21 788# and needs a lot of work at restructuring. It's also misindented
055fd3a9
GS
789# in many places.
790# + Fixed bug where trying to look at an option like your pager
e22ea7cc 791# shows "1".
055fd3a9
GS
792# + Fixed some $? processing. Note: if you use csh or tcsh, you will
793# lose. You should consider shell escapes not using their shell,
794# or else not caring about detailed status. This should really be
795# unified into one place, too.
796# + Fixed bug where invisible trailing whitespace on commands hoses you,
04e43a21 797# tricking Perl into thinking you weren't calling a debugger command!
055fd3a9
GS
798# + Fixed bug where leading whitespace on commands hoses you. (One
799# suggests a leading semicolon or any other irrelevant non-whitespace
800# to indicate literal Perl code.)
801# + Fixed bugs that ate warnings due to wrong selected handle.
802# + Fixed a precedence bug on signal stuff.
803# + Fixed some unseemly wording.
804# + Fixed bug in help command trying to call perl method code.
805# + Fixed to call dumpvar from exception handler. SIGPIPE killed us.
806# ENHANCEMENTS:
807# + Added some comments. This code is still nasty spaghetti.
808# + Added message if you clear your pre/post command stacks which was
809# very easy to do if you just typed a bare >, <, or {. (A command
810# without an argument should *never* be a destructive action; this
811# API is fundamentally screwed up; likewise option setting, which
812# is equally buggered.)
813# + Added command stack dump on argument of "?" for >, <, or {.
814# + Added a semi-built-in doc viewer command that calls man with the
815# proper %Config::Config path (and thus gets caching, man -k, etc),
816# or else perldoc on obstreperous platforms.
817# + Added to and rearranged the help information.
818# + Detected apparent misuse of { ... } to declare a block; this used
819# to work but now is a command, and mysteriously gave no complaint.
04e43a21
DL
820#
821# Changes: 1.08: Apr 25, 2001 Jon Eveland <jweveland@yahoo.com>
822# BUG FIX:
823# + This patch to perl5db.pl cleans up formatting issues on the help
824# summary (h h) screen in the debugger. Mostly columnar alignment
825# issues, plus converted the printed text to use all spaces, since
826# tabs don't seem to help much here.
827#
828# Changes: 1.09: May 19, 2001 Ilya Zakharevich <ilya@math.ohio-state.edu>
69893cff
RGS
829# Minor bugs corrected;
830# + Support for auto-creation of new TTY window on startup, either
831# unconditionally, or if started as a kid of another debugger session;
1f874cb6 832# + New 'O'ption CreateTTY
69893cff 833# I<CreateTTY> bits control attempts to create a new TTY on events:
e22ea7cc 834# 1: on fork()
69893cff
RGS
835# 2: debugger is started inside debugger
836# 4: on startup
837# + Code to auto-create a new TTY window on OS/2 (currently one
838# extra window per session - need named pipes to have more...);
839# + Simplified interface for custom createTTY functions (with a backward
840# compatibility hack); now returns the TTY name to use; return of ''
841# means that the function reset the I/O handles itself;
842# + Better message on the semantic of custom createTTY function;
843# + Convert the existing code to create a TTY into a custom createTTY
844# function;
845# + Consistent support for TTY names of the form "TTYin,TTYout";
846# + Switch line-tracing output too to the created TTY window;
1f874cb6 847# + make 'b fork' DWIM with CORE::GLOBAL::fork;
69893cff 848# + High-level debugger API cmd_*():
04e43a21
DL
849# cmd_b_load($filenamepart) # b load filenamepart
850# cmd_b_line($lineno [, $cond]) # b lineno [cond]
851# cmd_b_sub($sub [, $cond]) # b sub [cond]
852# cmd_stop() # Control-C
492652be 853# cmd_d($lineno) # d lineno (B)
04e43a21
DL
854# The cmd_*() API returns FALSE on failure; in this case it outputs
855# the error message to the debugging output.
69893cff 856# + Low-level debugger API
04e43a21
DL
857# break_on_load($filename) # b load filename
858# @files = report_break_on_load() # List files with load-breakpoints
859# breakable_line_in_filename($name, $from [, $to])
860# # First breakable line in the
861# # range $from .. $to. $to defaults
e22ea7cc 862# # to $from, and may be less than
69893cff 863# # $to
04e43a21
DL
864# breakable_line($from [, $to]) # Same for the current file
865# break_on_filename_line($name, $lineno [, $cond])
e22ea7cc 866# # Set breakpoint,$cond defaults to
69893cff 867# # 1
04e43a21
DL
868# break_on_filename_line_range($name, $from, $to [, $cond])
869# # As above, on the first
870# # breakable line in range
871# break_on_line($lineno [, $cond]) # As above, in the current file
872# break_subroutine($sub [, $cond]) # break on the first breakable line
873# ($name, $from, $to) = subroutine_filename_lines($sub)
874# # The range of lines of the text
875# The low-level API returns TRUE on success, and die()s on failure.
876#
877# Changes: 1.10: May 23, 2001 Daniel Lewart <d-lewart@uiuc.edu>
878# BUG FIXES:
879# + Fixed warnings generated by "perl -dWe 42"
880# + Corrected spelling errors
881# + Squeezed Help (h) output into 80 columns
600d99fa
DL
882#
883# Changes: 1.11: May 24, 2001 David Dyck <dcd@tc.fluke.com>
884# + Made "x @INC" work like it used to
885#
886# Changes: 1.12: May 24, 2001 Daniel Lewart <d-lewart@uiuc.edu>
887# + Fixed warnings generated by "O" (Show debugger options)
888# + Fixed warnings generated by "p 42" (Print expression)
6f891d7d 889# Changes: 1.13: Jun 19, 2001 Scott.L.Miller@compaq.com
e22ea7cc 890# + Added windowSize option
2f7e9187
MS
891# Changes: 1.14: Oct 9, 2001 multiple
892# + Clean up after itself on VMS (Charles Lane in 12385)
893# + Adding "@ file" syntax (Peter Scott in 12014)
894# + Debug reloading selfloaded stuff (Ilya Zakharevich in 11457)
895# + $^S and other debugger fixes (Ilya Zakharevich in 11120)
896# + Forgot a my() declaration (Ilya Zakharevich in 11085)
897# Changes: 1.15: Nov 6, 2001 Michael G Schwern <schwern@pobox.com>
898# + Updated 1.14 change log
98dc9551 899# + Added *dbline explanatory comments
2f7e9187 900# + Mentioning perldebguts man page
492652be 901# Changes: 1.16: Feb 15, 2002 Mark-Jason Dominus <mjd@plover.com>
69893cff 902# + $onetimeDump improvements
492652be
RF
903# Changes: 1.17: Feb 20, 2002 Richard Foley <richard.foley@rfi.net>
904# Moved some code to cmd_[.]()'s for clarity and ease of handling,
e22ea7cc
RF
905# rationalised the following commands and added cmd_wrapper() to
906# enable switching between old and frighteningly consistent new
492652be
RF
907# behaviours for diehards: 'o CommandSet=pre580' (sigh...)
908# a(add), A(del) # action expr (added del by line)
909# + b(add), B(del) # break [line] (was b,D)
e22ea7cc 910# + w(add), W(del) # watch expr (was W,W)
69893cff 911# # added del by expr
492652be
RF
912# + h(summary), h h(long) # help (hh) (was h h,h)
913# + m(methods), M(modules) # ... (was m,v)
914# + o(option) # lc (was O)
915# + v(view code), V(view Variables) # ... (was w,V)
aef14ef9
RF
916# Changes: 1.18: Mar 17, 2002 Richard Foley <richard.foley@rfi.net>
917# + fixed missing cmd_O bug
471505cc 918# Changes: 1.19: Mar 29, 2002 Spider Boardman
919# + Added missing local()s -- DB::DB is called recursively.
35408c4e
RF
920# Changes: 1.20: Feb 17, 2003 Richard Foley <richard.foley@rfi.net>
921# + pre'n'post commands no longer trashed with no args
922# + watch val joined out of eval()
69893cff
RGS
923# Changes: 1.21: Jun 04, 2003 Joe McMahon <mcmahon@ibiblio.org>
924# + Added comments and reformatted source. No bug fixes/enhancements.
925# + Includes cleanup by Robin Barker and Jarkko Hietaniemi.
926# Changes: 1.22 Jun 09, 2003 Alex Vandiver <alexmv@MIT.EDU>
927# + Flush stdout/stderr before the debugger prompt is printed.
928# Changes: 1.23: Dec 21, 2003 Dominique Quatravaux
de5e1a3d 929# + Fix a side-effect of bug #24674 in the perl debugger ("odd taint bug")
e219e2fb
RF
930# Changes: 1.24: Mar 03, 2004 Richard Foley <richard.foley@rfi.net>
931# + Added command to save all debugger commands for sourcing later.
3c4b39be 932# + Added command to display parent inheritance tree of given class.
e219e2fb 933# + Fixed minor newline in history bug.
e22ea7cc
RF
934# Changes: 1.25: Apr 17, 2004 Richard Foley <richard.foley@rfi.net>
935# + Fixed option bug (setting invalid options + not recognising valid short forms)
936# Changes: 1.26: Apr 22, 2004 Richard Foley <richard.foley@rfi.net>
937# + unfork the 5.8.x and 5.9.x debuggers.
938# + whitespace and assertions call cleanup across versions
939# + H * deletes (resets) history
940# + i now handles Class + blessed objects
7fddc82f
RF
941# Changes: 1.27: May 09, 2004 Richard Foley <richard.foley@rfi.net>
942# + updated pod page references - clunky.
943# + removed windowid restriction for forking into an xterm.
944# + more whitespace again.
945# + wrapped restart and enabled rerun [-n] (go back n steps) command.
2cbb2ee1
RGS
946# Changes: 1.28: Oct 12, 2004 Richard Foley <richard.foley@rfi.net>
947# + Added threads support (inc. e and E commands)
6fae1ad7
RF
948# Changes: 1.29: Nov 28, 2006 Bo Lindbergh <blgl@hagernas.com>
949# + Added macosx_get_fork_TTY support
5561b870
AK
950# Changes: 1.30: Mar 06, 2007 Andreas Koenig <andk@cpan.org>
951# + Added HistFile, HistSize
98960e6a
NC
952# Changes: 1.31
953# + Remove support for assertions and -A
954# + stop NEXT::AUTOLOAD from emitting warnings under the debugger. RT #25053
955# + "update for Mac OS X 10.5" [finding the tty device]
956# + "What I needed to get the forked debugger to work" [on VMS]
957# + [perl #57016] debugger: o warn=0 die=0 ignored
958# + Note, but don't use, PERLDBf_SAVESRC
959# + Fix #7013: lvalue subs not working inside debugger
b468dcb6
DL
960# Changes: 1.32: Jun 03, 2009 Jonathan Leto <jonathan@leto.net>
961# + Fix bug where a key _< with undefined value was put into the symbol table
962# + when the $filename variable is not set
330ac782
JJ
963# Changes: 1.33:
964# + Debugger prints lines to the remote port when it forks and openes a new port (f633fd2)
965# + The debugger now continues to use RemotePort when it's been configured to use it. (11653f7)
966# + Stop using $ENV{LESS} for parameters not intended for less (d463cf2)
967# + Configure has a path to less and perl5db.pl can use it (bf320d6)
968# + Die with $@ instead of empty message (86755f4)
969# + Remove extra/useless $@ check after eval { require PadWalker } (which is still checked) (dab8d6d)
970# + Promote eval( "require ..." ) to eval { require ... } (4a49187)
971# + Promote eval { require( ... )} || die to mere require( ... ) (999f23b)
972# + Remove indirect object notation from debugger (bee4b46)
973# + Document that @{$main::{'_<'.$filename}} lines are dualvar to (COP*). (7e17a74)
974# + Remove MacOS classic support from the debugger. (2b894b7)
6fae1ad7 975########################################################################
d338d6fe 976
69893cff
RGS
977=head1 DEBUGGER INITIALIZATION
978
979The debugger starts up in phases.
980
981=head2 BASIC SETUP
982
983First, it initializes the environment it wants to run in: turning off
984warnings during its own compilation, defining variables which it will need
985to avoid warnings later, setting itself up to not exit when the program
986terminates, and defaulting to printing return values for the C<r> command.
987
988=cut
989
eda6e075 990# Needed for the statement after exec():
69893cff
RGS
991#
992# This BEGIN block is simply used to switch off warnings during debugger
98dc9551 993# compilation. Probably it would be better practice to fix the warnings,
69893cff 994# but this is how it's done at the moment.
eda6e075 995
e22ea7cc
RF
996BEGIN {
997 $ini_warn = $^W;
998 $^W = 0;
999} # Switch compilation warnings off until another BEGIN.
d12a4851 1000
69893cff
RGS
1001local ($^W) = 0; # Switch run-time warnings off during init.
1002
2cbb2ee1
RGS
1003=head2 THREADS SUPPORT
1004
1005If we are running under a threaded Perl, we require threads and threads::shared
1006if the environment variable C<PERL5DB_THREADED> is set, to enable proper
1007threaded debugger control. C<-dt> can also be used to set this.
1008
1009Each new thread will be announced and the debugger prompt will always inform
1010you of each new thread created. It will also indicate the thread id in which
1011we are currently running within the prompt like this:
1012
1013 [tid] DB<$i>
1014
1015Where C<[tid]> is an integer thread id and C<$i> is the familiar debugger
1016command prompt. The prompt will show: C<[0]> when running under threads, but
1017not actually in a thread. C<[tid]> is consistent with C<gdb> usage.
1018
1019While running under threads, when you set or delete a breakpoint (etc.), this
1020will apply to all threads, not just the currently running one. When you are
1021in a currently executing thread, you will stay there until it completes. With
1022the current implementation it is not currently possible to hop from one thread
1023to another.
1024
1025The C<e> and C<E> commands are currently fairly minimal - see C<h e> and C<h E>.
1026
1027Note that threading support was built into the debugger as of Perl version
1028C<5.8.6> and debugger version C<1.2.8>.
1029
1030=cut
1031
1032BEGIN {
1033 # ensure we can share our non-threaded variables or no-op
1034 if ($ENV{PERL5DB_THREADED}) {
1035 require threads;
1036 require threads::shared;
1037 import threads::shared qw(share);
1038 $DBGR;
1039 share(\$DBGR);
1040 lock($DBGR);
1041 print "Threads support enabled\n";
1042 } else {
1043 *lock = sub(*) {};
1044 *share = sub(*) {};
1045 }
1046}
1047
69893cff
RGS
1048# This would probably be better done with "use vars", but that wasn't around
1049# when this code was originally written. (Neither was "use strict".) And on
1050# the principle of not fiddling with something that was working, this was
1051# left alone.
1052warn( # Do not ;-)
2cbb2ee1 1053 # These variables control the execution of 'dumpvar.pl'.
69893cff
RGS
1054 $dumpvar::hashDepth,
1055 $dumpvar::arrayDepth,
1056 $dumpvar::dumpDBFiles,
1057 $dumpvar::dumpPackages,
1058 $dumpvar::quoteHighBit,
1059 $dumpvar::printUndef,
1060 $dumpvar::globPrint,
1061 $dumpvar::usageOnly,
1062
1063 # used to save @ARGV and extract any debugger-related flags.
1064 @ARGS,
1065
1066 # used to control die() reporting in diesignal()
1067 $Carp::CarpLevel,
1068
1069 # used to prevent multiple entries to diesignal()
1070 # (if for instance diesignal() itself dies)
1071 $panic,
1072
1073 # used to prevent the debugger from running nonstop
1074 # after a restart
1075 $second_time,
1076 )
1077 if 0;
d338d6fe 1078
422c59bf 1079# without threads, $filename is not defined until DB::DB is called
2cbb2ee1 1080foreach my $k (keys (%INC)) {
bc6438f2 1081 &share(\$main::{'_<'.$filename}) if defined $filename;
2cbb2ee1
RGS
1082};
1083
54d04a52 1084# Command-line + PERLLIB:
69893cff 1085# Save the contents of @INC before they are modified elsewhere.
54d04a52
IZ
1086@ini_INC = @INC;
1087
69893cff
RGS
1088# This was an attempt to clear out the previous values of various
1089# trapped errors. Apparently it didn't help. XXX More info needed!
d338d6fe
PP
1090# $prevwarn = $prevdie = $prevbus = $prevsegv = ''; # Does not help?!
1091
69893cff
RGS
1092# We set these variables to safe values. We don't want to blindly turn
1093# off warnings, because other packages may still want them.
e22ea7cc
RF
1094$trace = $signal = $single = 0; # Uninitialized warning suppression
1095 # (local $^W cannot help - other packages!).
69893cff
RGS
1096
1097# Default to not exiting when program finishes; print the return
1098# value when the 'r' command is used to return from a subroutine.
55497cff 1099$inhibit_exit = $option{PrintRet} = 1;
d338d6fe 1100
69893cff
RGS
1101=head1 OPTION PROCESSING
1102
1103The debugger's options are actually spread out over the debugger itself and
1104C<dumpvar.pl>; some of these are variables to be set, while others are
1105subs to be called with a value. To try to make this a little easier to
1106manage, the debugger uses a few data structures to define what options
1107are legal and how they are to be processed.
1108
1109First, the C<@options> array defines the I<names> of all the options that
1110are to be accepted.
1111
1112=cut
1113
1114@options = qw(
5561b870 1115 CommandSet HistFile HistSize
e22ea7cc
RF
1116 hashDepth arrayDepth dumpDepth
1117 DumpDBFiles DumpPackages DumpReused
1118 compactDump veryCompact quote
1119 HighBit undefPrint globPrint
1120 PrintRet UsageOnly frame
1121 AutoTrace TTY noTTY
1122 ReadLine NonStop LineInfo
1123 maxTraceLen recallCommand ShellBang
1124 pager tkRunning ornaments
1125 signalLevel warnLevel dieLevel
1126 inhibit_exit ImmediateStop bareStringify
1127 CreateTTY RemotePort windowSize
584420f0 1128 DollarCaretP
e22ea7cc 1129);
d12a4851 1130
584420f0 1131@RememberOnROptions = qw(DollarCaretP);
d12a4851 1132
69893cff
RGS
1133=pod
1134
1135Second, C<optionVars> lists the variables that each option uses to save its
1136state.
1137
1138=cut
1139
1140%optionVars = (
e22ea7cc
RF
1141 hashDepth => \$dumpvar::hashDepth,
1142 arrayDepth => \$dumpvar::arrayDepth,
1143 CommandSet => \$CommandSet,
1144 DumpDBFiles => \$dumpvar::dumpDBFiles,
1145 DumpPackages => \$dumpvar::dumpPackages,
1146 DumpReused => \$dumpvar::dumpReused,
1147 HighBit => \$dumpvar::quoteHighBit,
1148 undefPrint => \$dumpvar::printUndef,
1149 globPrint => \$dumpvar::globPrint,
1150 UsageOnly => \$dumpvar::usageOnly,
1151 CreateTTY => \$CreateTTY,
1152 bareStringify => \$dumpvar::bareStringify,
1153 frame => \$frame,
1154 AutoTrace => \$trace,
1155 inhibit_exit => \$inhibit_exit,
1156 maxTraceLen => \$maxtrace,
1157 ImmediateStop => \$ImmediateStop,
1158 RemotePort => \$remoteport,
1159 windowSize => \$window,
5561b870
AK
1160 HistFile => \$histfile,
1161 HistSize => \$histsize,
69893cff
RGS
1162);
1163
1164=pod
1165
1166Third, C<%optionAction> defines the subroutine to be called to process each
1167option.
1168
1169=cut
1170
1171%optionAction = (
1172 compactDump => \&dumpvar::compactDump,
1173 veryCompact => \&dumpvar::veryCompact,
1174 quote => \&dumpvar::quote,
1175 TTY => \&TTY,
1176 noTTY => \&noTTY,
1177 ReadLine => \&ReadLine,
1178 NonStop => \&NonStop,
1179 LineInfo => \&LineInfo,
1180 recallCommand => \&recallCommand,
1181 ShellBang => \&shellBang,
1182 pager => \&pager,
1183 signalLevel => \&signalLevel,
1184 warnLevel => \&warnLevel,
1185 dieLevel => \&dieLevel,
1186 tkRunning => \&tkRunning,
1187 ornaments => \&ornaments,
1188 RemotePort => \&RemotePort,
1189 DollarCaretP => \&DollarCaretP,
d12a4851
JH
1190);
1191
69893cff
RGS
1192=pod
1193
1194Last, the C<%optionRequire> notes modules that must be C<require>d if an
1195option is used.
1196
1197=cut
d338d6fe 1198
69893cff
RGS
1199# Note that this list is not complete: several options not listed here
1200# actually require that dumpvar.pl be loaded for them to work, but are
1201# not in the table. A subsequent patch will correct this problem; for
1202# the moment, we're just recommenting, and we are NOT going to change
1203# function.
eda6e075 1204%optionRequire = (
69893cff
RGS
1205 compactDump => 'dumpvar.pl',
1206 veryCompact => 'dumpvar.pl',
1207 quote => 'dumpvar.pl',
e22ea7cc 1208);
69893cff
RGS
1209
1210=pod
1211
1212There are a number of initialization-related variables which can be set
1213by putting code to set them in a BEGIN block in the C<PERL5DB> environment
1214variable. These are:
1215
1216=over 4
1217
1218=item C<$rl> - readline control XXX needs more explanation
1219
1220=item C<$warnLevel> - whether or not debugger takes over warning handling
1221
1222=item C<$dieLevel> - whether or not debugger takes over die handling
1223
1224=item C<$signalLevel> - whether or not debugger takes over signal handling
1225
1226=item C<$pre> - preprompt actions (array reference)
1227
1228=item C<$post> - postprompt actions (array reference)
1229
1230=item C<$pretype>
1231
1232=item C<$CreateTTY> - whether or not to create a new TTY for this debugger
1233
1234=item C<$CommandSet> - which command set to use (defaults to new, documented set)
1235
1236=back
1237
1238=cut
d338d6fe
PP
1239
1240# These guys may be defined in $ENV{PERL5DB} :
69893cff
RGS
1241$rl = 1 unless defined $rl;
1242$warnLevel = 1 unless defined $warnLevel;
1243$dieLevel = 1 unless defined $dieLevel;
1244$signalLevel = 1 unless defined $signalLevel;
1245$pre = [] unless defined $pre;
1246$post = [] unless defined $post;
1247$pretype = [] unless defined $pretype;
1248$CreateTTY = 3 unless defined $CreateTTY;
1249$CommandSet = '580' unless defined $CommandSet;
1250
2cbb2ee1
RGS
1251share($rl);
1252share($warnLevel);
1253share($dieLevel);
1254share($signalLevel);
1255share($pre);
1256share($post);
1257share($pretype);
1258share($rl);
1259share($CreateTTY);
1260share($CommandSet);
1261
69893cff
RGS
1262=pod
1263
1264The default C<die>, C<warn>, and C<signal> handlers are set up.
1265
1266=cut
055fd3a9 1267
d338d6fe
PP
1268warnLevel($warnLevel);
1269dieLevel($dieLevel);
1270signalLevel($signalLevel);
055fd3a9 1271
69893cff
RGS
1272=pod
1273
1274The pager to be used is needed next. We try to get it from the
5561b870 1275environment first. If it's not defined there, we try to find it in
69893cff
RGS
1276the Perl C<Config.pm>. If it's not there, we default to C<more>. We
1277then call the C<pager()> function to save the pager name.
1278
1279=cut
1280
1281# This routine makes sure $pager is set up so that '|' can use it.
4865a36d 1282pager(
e22ea7cc 1283
69893cff 1284 # If PAGER is defined in the environment, use it.
e22ea7cc
RF
1285 defined $ENV{PAGER}
1286 ? $ENV{PAGER}
69893cff
RGS
1287
1288 # If not, see if Config.pm defines it.
e22ea7cc
RF
1289 : eval { require Config }
1290 && defined $Config::Config{pager}
1291 ? $Config::Config{pager}
69893cff
RGS
1292
1293 # If not, fall back to 'more'.
e22ea7cc
RF
1294 : 'more'
1295 )
1296 unless defined $pager;
69893cff
RGS
1297
1298=pod
1299
1300We set up the command to be used to access the man pages, the command
be9a9b1d
AT
1301recall character (C<!> unless otherwise defined) and the shell escape
1302character (C<!> unless otherwise defined). Yes, these do conflict, and
69893cff
RGS
1303neither works in the debugger at the moment.
1304
1305=cut
1306
055fd3a9 1307setman();
69893cff
RGS
1308
1309# Set up defaults for command recall and shell escape (note:
1310# these currently don't work in linemode debugging).
d338d6fe 1311&recallCommand("!") unless defined $prc;
69893cff
RGS
1312&shellBang("!") unless defined $psh;
1313
1314=pod
1315
1316We then set up the gigantic string containing the debugger help.
1317We also set the limit on the number of arguments we'll display during a
1318trace.
1319
1320=cut
1321
04e43a21 1322sethelp();
69893cff
RGS
1323
1324# If we didn't get a default for the length of eval/stack trace args,
1325# set it here.
1d06cb2d 1326$maxtrace = 400 unless defined $maxtrace;
69893cff
RGS
1327
1328=head2 SETTING UP THE DEBUGGER GREETING
1329
be9a9b1d 1330The debugger I<greeting> helps to inform the user how many debuggers are
69893cff
RGS
1331running, and whether the current debugger is the primary or a child.
1332
1333If we are the primary, we just hang onto our pid so we'll have it when
1334or if we start a child debugger. If we are a child, we'll set things up
1335so we'll have a unique greeting and so the parent will give us our own
1336TTY later.
1337
1338We save the current contents of the C<PERLDB_PIDS> environment variable
1339because we mess around with it. We'll also need to hang onto it because
1340we'll need it if we restart.
1341
1342Child debuggers make a label out of the current PID structure recorded in
1343PERLDB_PIDS plus the new PID. They also mark themselves as not having a TTY
1344yet so the parent will give them one later via C<resetterm()>.
1345
1346=cut
1347
e22ea7cc 1348# Save the current contents of the environment; we're about to
69893cff 1349# much with it. We'll need this if we have to restart.
f1583d8f 1350$ini_pids = $ENV{PERLDB_PIDS};
69893cff 1351
e22ea7cc
RF
1352if ( defined $ENV{PERLDB_PIDS} ) {
1353
69893cff 1354 # We're a child. Make us a label out of the current PID structure
e22ea7cc 1355 # recorded in PERLDB_PIDS plus our (new) PID. Mark us as not having
69893cff 1356 # a term yet so the parent will give us one later via resetterm().
55f4245e
JM
1357
1358 my $env_pids = $ENV{PERLDB_PIDS};
1359 $pids = "[$env_pids]";
1360
1361 # Unless we are on OpenVMS, all programs under the DCL shell run under
1362 # the same PID.
1363
1364 if (($^O eq 'VMS') && ($env_pids =~ /\b$$\b/)) {
1365 $term_pid = $$;
1366 }
1367 else {
1368 $ENV{PERLDB_PIDS} .= "->$$";
1369 $term_pid = -1;
1370 }
1371
69893cff
RGS
1372} ## end if (defined $ENV{PERLDB_PIDS...
1373else {
e22ea7cc
RF
1374
1375 # We're the parent PID. Initialize PERLDB_PID in case we end up with a
69893cff
RGS
1376 # child debugger, and mark us as the parent, so we'll know to set up
1377 # more TTY's is we have to.
1378 $ENV{PERLDB_PIDS} = "$$";
619a0444 1379 $pids = "[pid=$$]";
e22ea7cc 1380 $term_pid = $$;
f1583d8f 1381}
69893cff 1382
f1583d8f 1383$pidprompt = '';
69893cff
RGS
1384
1385# Sets up $emacs as a synonym for $slave_editor.
1386*emacs = $slave_editor if $slave_editor; # May be used in afterinit()...
1387
1388=head2 READING THE RC FILE
1389
1390The debugger will read a file of initialization options if supplied. If
1391running interactively, this is C<.perldb>; if not, it's C<perldb.ini>.
1392
1393=cut
1394
1395# As noted, this test really doesn't check accurately that the debugger
1396# is running at a terminal or not.
d338d6fe 1397
98274836
JM
1398my $dev_tty = '/dev/tty';
1399 $dev_tty = 'TT:' if ($^O eq 'VMS');
1400if ( -e $dev_tty ) { # this is the wrong metric!
e22ea7cc
RF
1401 $rcfile = ".perldb";
1402}
69893cff
RGS
1403else {
1404 $rcfile = "perldb.ini";
d338d6fe
PP
1405}
1406
69893cff
RGS
1407=pod
1408
1409The debugger does a safety test of the file to be read. It must be owned
1410either by the current user or root, and must only be writable by the owner.
1411
1412=cut
1413
1414# This wraps a safety test around "do" to read and evaluate the init file.
1415#
055fd3a9
GS
1416# This isn't really safe, because there's a race
1417# between checking and opening. The solution is to
1418# open and fstat the handle, but then you have to read and
1419# eval the contents. But then the silly thing gets
69893cff
RGS
1420# your lexical scope, which is unfortunate at best.
1421sub safe_do {
055fd3a9
GS
1422 my $file = shift;
1423
1424 # Just exactly what part of the word "CORE::" don't you understand?
69893cff
RGS
1425 local $SIG{__WARN__};
1426 local $SIG{__DIE__};
055fd3a9 1427
e22ea7cc 1428 unless ( is_safe_file($file) ) {
69893cff 1429 CORE::warn <<EO_GRIPE;
055fd3a9
GS
1430perldb: Must not source insecure rcfile $file.
1431 You or the superuser must be the owner, and it must not
69893cff 1432 be writable by anyone but its owner.
055fd3a9 1433EO_GRIPE
69893cff
RGS
1434 return;
1435 } ## end unless (is_safe_file($file...
055fd3a9
GS
1436
1437 do $file;
1438 CORE::warn("perldb: couldn't parse $file: $@") if $@;
69893cff 1439} ## end sub safe_do
055fd3a9 1440
69893cff
RGS
1441# This is the safety test itself.
1442#
055fd3a9
GS
1443# Verifies that owner is either real user or superuser and that no
1444# one but owner may write to it. This function is of limited use
1445# when called on a path instead of upon a handle, because there are
1446# no guarantees that filename (by dirent) whose file (by ino) is
e22ea7cc 1447# eventually accessed is the same as the one tested.
055fd3a9
GS
1448# Assumes that the file's existence is not in doubt.
1449sub is_safe_file {
1450 my $path = shift;
69893cff 1451 stat($path) || return; # mysteriously vaporized
e22ea7cc 1452 my ( $dev, $ino, $mode, $nlink, $uid, $gid ) = stat(_);
055fd3a9
GS
1453
1454 return 0 if $uid != 0 && $uid != $<;
1455 return 0 if $mode & 022;
1456 return 1;
69893cff 1457} ## end sub is_safe_file
055fd3a9 1458
69893cff 1459# If the rcfile (whichever one we decided was the right one to read)
e22ea7cc
RF
1460# exists, we safely do it.
1461if ( -f $rcfile ) {
055fd3a9 1462 safe_do("./$rcfile");
69893cff 1463}
e22ea7cc 1464
69893cff 1465# If there isn't one here, try the user's home directory.
e22ea7cc 1466elsif ( defined $ENV{HOME} && -f "$ENV{HOME}/$rcfile" ) {
055fd3a9
GS
1467 safe_do("$ENV{HOME}/$rcfile");
1468}
e22ea7cc 1469
69893cff 1470# Else try the login directory.
e22ea7cc 1471elsif ( defined $ENV{LOGDIR} && -f "$ENV{LOGDIR}/$rcfile" ) {
055fd3a9 1472 safe_do("$ENV{LOGDIR}/$rcfile");
d338d6fe
PP
1473}
1474
69893cff 1475# If the PERLDB_OPTS variable has options in it, parse those out next.
e22ea7cc
RF
1476if ( defined $ENV{PERLDB_OPTS} ) {
1477 parse_options( $ENV{PERLDB_OPTS} );
d338d6fe
PP
1478}
1479
69893cff
RGS
1480=pod
1481
1482The last thing we do during initialization is determine which subroutine is
1483to be used to obtain a new terminal when a new debugger is started. Right now,
b0b54b5e 1484the debugger only handles TCP sockets, X11, OS/2, amd Mac OS X
11653f7f 1485(darwin).
69893cff
RGS
1486
1487=cut
1488
1489# Set up the get_fork_TTY subroutine to be aliased to the proper routine.
1490# Works if you're running an xterm or xterm-like window, or you're on
6fae1ad7
RF
1491# OS/2, or on Mac OS X. This may need some expansion.
1492
1493if (not defined &get_fork_TTY) # only if no routine exists
69893cff 1494{
11653f7f
JJ
1495 if ( defined $remoteport ) {
1496 # Expect an inetd-like server
1497 *get_fork_TTY = \&socket_get_fork_TTY; # to listen to us
1498 }
1499 elsif (defined $ENV{TERM} # If we know what kind
6fae1ad7
RF
1500 # of terminal this is,
1501 and $ENV{TERM} eq 'xterm' # and it's an xterm,
1502 and defined $ENV{DISPLAY} # and what display it's on,
1503 )
1504 {
1505 *get_fork_TTY = \&xterm_get_fork_TTY; # use the xterm version
1506 }
1507 elsif ( $^O eq 'os2' ) { # If this is OS/2,
1508 *get_fork_TTY = \&os2_get_fork_TTY; # use the OS/2 version
1509 }
1510 elsif ( $^O eq 'darwin' # If this is Mac OS X
1511 and defined $ENV{TERM_PROGRAM} # and we're running inside
1512 and $ENV{TERM_PROGRAM}
1513 eq 'Apple_Terminal' # Terminal.app
1514 )
1515 {
1516 *get_fork_TTY = \&macosx_get_fork_TTY; # use the Mac OS X version
1517 }
69893cff 1518} ## end if (not defined &get_fork_TTY...
e22ea7cc 1519
dbb46cec
DQ
1520# untaint $^O, which may have been tainted by the last statement.
1521# see bug [perl #24674]
e22ea7cc
RF
1522$^O =~ m/^(.*)\z/;
1523$^O = $1;
f1583d8f 1524
d12a4851 1525# Here begin the unreadable code. It needs fixing.
055fd3a9 1526
69893cff
RGS
1527=head2 RESTART PROCESSING
1528
1529This section handles the restart command. When the C<R> command is invoked, it
1530tries to capture all of the state it can into environment variables, and
1531then sets C<PERLDB_RESTART>. When we start executing again, we check to see
1532if C<PERLDB_RESTART> is there; if so, we reload all the information that
1533the R command stuffed into the environment variables.
1534
1535 PERLDB_RESTART - flag only, contains no restart data itself.
1536 PERLDB_HIST - command history, if it's available
1537 PERLDB_ON_LOAD - breakpoints set by the rc file
1538 PERLDB_POSTPONE - subs that have been loaded/not executed, and have actions
1539 PERLDB_VISITED - files that had breakpoints
1540 PERLDB_FILE_... - breakpoints for a file
1541 PERLDB_OPT - active options
1542 PERLDB_INC - the original @INC
1543 PERLDB_PRETYPE - preprompt debugger actions
1544 PERLDB_PRE - preprompt Perl code
1545 PERLDB_POST - post-prompt Perl code
1546 PERLDB_TYPEAHEAD - typeahead captured by readline()
1547
1548We chug through all these variables and plug the values saved in them
1549back into the appropriate spots in the debugger.
1550
1551=cut
1552
e22ea7cc
RF
1553if ( exists $ENV{PERLDB_RESTART} ) {
1554
69893cff 1555 # We're restarting, so we don't need the flag that says to restart anymore.
e22ea7cc
RF
1556 delete $ENV{PERLDB_RESTART};
1557
1558 # $restart = 1;
1559 @hist = get_list('PERLDB_HIST');
1560 %break_on_load = get_list("PERLDB_ON_LOAD");
1561 %postponed = get_list("PERLDB_POSTPONE");
69893cff 1562
2cbb2ee1
RGS
1563 share(@hist);
1564 share(@truehist);
1565 share(%break_on_load);
1566 share(%postponed);
1567
69893cff 1568 # restore breakpoints/actions
e22ea7cc
RF
1569 my @had_breakpoints = get_list("PERLDB_VISITED");
1570 for ( 0 .. $#had_breakpoints ) {
1571 my %pf = get_list("PERLDB_FILE_$_");
1572 $postponed_file{ $had_breakpoints[$_] } = \%pf if %pf;
1573 }
69893cff
RGS
1574
1575 # restore options
e22ea7cc
RF
1576 my %opt = get_list("PERLDB_OPT");
1577 my ( $opt, $val );
1578 while ( ( $opt, $val ) = each %opt ) {
1579 $val =~ s/[\\\']/\\$1/g;
1580 parse_options("$opt'$val'");
1581 }
69893cff
RGS
1582
1583 # restore original @INC
e22ea7cc
RF
1584 @INC = get_list("PERLDB_INC");
1585 @ini_INC = @INC;
1586
1587 # return pre/postprompt actions and typeahead buffer
1588 $pretype = [ get_list("PERLDB_PRETYPE") ];
1589 $pre = [ get_list("PERLDB_PRE") ];
1590 $post = [ get_list("PERLDB_POST") ];
1591 @typeahead = get_list( "PERLDB_TYPEAHEAD", @typeahead );
69893cff
RGS
1592} ## end if (exists $ENV{PERLDB_RESTART...
1593
1594=head2 SETTING UP THE TERMINAL
1595
1596Now, we'll decide how the debugger is going to interact with the user.
1597If there's no TTY, we set the debugger to run non-stop; there's not going
1598to be anyone there to enter commands.
1599
1600=cut
54d04a52 1601
d338d6fe 1602if ($notty) {
69893cff 1603 $runnonstop = 1;
2cbb2ee1 1604 share($runnonstop);
69893cff 1605}
d12a4851 1606
69893cff
RGS
1607=pod
1608
1609If there is a TTY, we have to determine who it belongs to before we can
1610proceed. If this is a slave editor or graphical debugger (denoted by
1611the first command-line switch being '-emacs'), we shift this off and
1612set C<$rl> to 0 (XXX ostensibly to do straight reads).
1613
1614=cut
1615
1616else {
e22ea7cc 1617
69893cff
RGS
1618 # Is Perl being run from a slave editor or graphical debugger?
1619 # If so, don't use readline, and set $slave_editor = 1.
e22ea7cc
RF
1620 $slave_editor =
1621 ( ( defined $main::ARGV[0] ) and ( $main::ARGV[0] eq '-emacs' ) );
1622 $rl = 0, shift(@main::ARGV) if $slave_editor;
1623
1624 #require Term::ReadLine;
d12a4851 1625
69893cff
RGS
1626=pod
1627
1628We then determine what the console should be on various systems:
1629
1630=over 4
1631
1632=item * Cygwin - We use C<stdin> instead of a separate device.
1633
1634=cut
1635
e22ea7cc
RF
1636 if ( $^O eq 'cygwin' ) {
1637
69893cff
RGS
1638 # /dev/tty is binary. use stdin for textmode
1639 undef $console;
1640 }
1641
1642=item * Unix - use C</dev/tty>.
1643
1644=cut
1645
e22ea7cc 1646 elsif ( -e "/dev/tty" ) {
69893cff
RGS
1647 $console = "/dev/tty";
1648 }
1649
1650=item * Windows or MSDOS - use C<con>.
1651
1652=cut
1653
e22ea7cc 1654 elsif ( $^O eq 'dos' or -e "con" or $^O eq 'MSWin32' ) {
69893cff
RGS
1655 $console = "con";
1656 }
1657
69893cff
RGS
1658=item * VMS - use C<sys$command>.
1659
1660=cut
1661
1662 else {
e22ea7cc 1663
69893cff
RGS
1664 # everything else is ...
1665 $console = "sys\$command";
d12a4851 1666 }
69893cff
RGS
1667
1668=pod
1669
1670=back
1671
1672Several other systems don't use a specific console. We C<undef $console>
1673for those (Windows using a slave editor/graphical debugger, NetWare, OS/2
1674with a slave editor, Epoc).
1675
1676=cut
d12a4851 1677
e22ea7cc
RF
1678 if ( ( $^O eq 'MSWin32' ) and ( $slave_editor or defined $ENV{EMACS} ) ) {
1679
69893cff 1680 # /dev/tty is binary. use stdin for textmode
e22ea7cc
RF
1681 $console = undef;
1682 }
1683
1684 if ( $^O eq 'NetWare' ) {
d12a4851 1685
69893cff
RGS
1686 # /dev/tty is binary. use stdin for textmode
1687 $console = undef;
1688 }
d12a4851 1689
69893cff
RGS
1690 # In OS/2, we need to use STDIN to get textmode too, even though
1691 # it pretty much looks like Unix otherwise.
e22ea7cc
RF
1692 if ( defined $ENV{OS2_SHELL} and ( $slave_editor or $ENV{WINDOWID} ) )
1693 { # In OS/2
1694 $console = undef;
1695 }
1696
1697 # EPOC also falls into the 'got to use STDIN' camp.
1698 if ( $^O eq 'epoc' ) {
1699 $console = undef;
1700 }
d12a4851 1701
69893cff
RGS
1702=pod
1703
1704If there is a TTY hanging around from a parent, we use that as the console.
1705
1706=cut
1707
e22ea7cc 1708 $console = $tty if defined $tty;
d12a4851 1709
69893cff
RGS
1710=head2 SOCKET HANDLING
1711
1712The debugger is capable of opening a socket and carrying out a debugging
1713session over the socket.
1714
1715If C<RemotePort> was defined in the options, the debugger assumes that it
1716should try to start a debugging session on that port. It builds the socket
1717and then tries to connect the input and output filehandles to it.
1718
1719=cut
1720
1721 # Handle socket stuff.
e22ea7cc
RF
1722
1723 if ( defined $remoteport ) {
1724
69893cff
RGS
1725 # If RemotePort was defined in the options, connect input and output
1726 # to the socket.
11653f7f 1727 $IN = $OUT = connect_remoteport();
69893cff
RGS
1728 } ## end if (defined $remoteport)
1729
1730=pod
1731
1732If no C<RemotePort> was defined, and we want to create a TTY on startup,
1733this is probably a situation where multiple debuggers are running (for example,
1734a backticked command that starts up another debugger). We create a new IN and
1735OUT filehandle, and do the necessary mojo to create a new TTY if we know how
1736and if we can.
1737
1738=cut
1739
1740 # Non-socket.
1741 else {
e22ea7cc 1742
69893cff
RGS
1743 # Two debuggers running (probably a system or a backtick that invokes
1744 # the debugger itself under the running one). create a new IN and OUT
e22ea7cc 1745 # filehandle, and do the necessary mojo to create a new tty if we
69893cff 1746 # know how, and we can.
e22ea7cc
RF
1747 create_IN_OUT(4) if $CreateTTY & 4;
1748 if ($console) {
1749
69893cff 1750 # If we have a console, check to see if there are separate ins and
cd1191f1 1751 # outs to open. (They are assumed identical if not.)
69893cff 1752
e22ea7cc
RF
1753 my ( $i, $o ) = split /,/, $console;
1754 $o = $i unless defined $o;
69893cff 1755
69893cff 1756 # read/write on in, or just read, or read on STDIN.
e22ea7cc
RF
1757 open( IN, "+<$i" )
1758 || open( IN, "<$i" )
1759 || open( IN, "<&STDIN" );
1760
69893cff
RGS
1761 # read/write/create/clobber out, or write/create/clobber out,
1762 # or merge with STDERR, or merge with STDOUT.
e22ea7cc
RF
1763 open( OUT, "+>$o" )
1764 || open( OUT, ">$o" )
1765 || open( OUT, ">&STDERR" )
1766 || open( OUT, ">&STDOUT" ); # so we don't dongle stdout
1767
1768 } ## end if ($console)
1769 elsif ( not defined $console ) {
1770
1771 # No console. Open STDIN.
1772 open( IN, "<&STDIN" );
1773
1774 # merge with STDERR, or with STDOUT.
1775 open( OUT, ">&STDERR" )
1776 || open( OUT, ">&STDOUT" ); # so we don't dongle stdout
1777 $console = 'STDIN/OUT';
69893cff
RGS
1778 } ## end elsif (not defined $console)
1779
1780 # Keep copies of the filehandles so that when the pager runs, it
1781 # can close standard input without clobbering ours.
e22ea7cc
RF
1782 $IN = \*IN, $OUT = \*OUT if $console or not defined $console;
1783 } ## end elsif (from if(defined $remoteport))
1784
1785 # Unbuffer DB::OUT. We need to see responses right away.
1786 my $previous = select($OUT);
1787 $| = 1; # for DB::OUT
1788 select($previous);
1789
1790 # Line info goes to debugger output unless pointed elsewhere.
1791 # Pointing elsewhere makes it possible for slave editors to
1792 # keep track of file and position. We have both a filehandle
1793 # and a I/O description to keep track of.
1794 $LINEINFO = $OUT unless defined $LINEINFO;
1795 $lineinfo = $console unless defined $lineinfo;
2cbb2ee1
RGS
1796 # share($LINEINFO); # <- unable to share globs
1797 share($lineinfo); #
e22ea7cc 1798
69893cff
RGS
1799=pod
1800
1801To finish initialization, we show the debugger greeting,
1802and then call the C<afterinit()> subroutine if there is one.
1803
1804=cut
d12a4851 1805
e22ea7cc
RF
1806 # Show the debugger greeting.
1807 $header =~ s/.Header: ([^,]+),v(\s+\S+\s+\S+).*$/$1$2/;
1808 unless ($runnonstop) {
1809 local $\ = '';
1810 local $, = '';
1811 if ( $term_pid eq '-1' ) {
1812 print $OUT "\nDaughter DB session started...\n";
1813 }
1814 else {
1815 print $OUT "\nLoading DB routines from $header\n";
1816 print $OUT (
1817 "Editor support ",
1818 $slave_editor ? "enabled" : "available", ".\n"
1819 );
1820 print $OUT
1f874cb6 1821"\nEnter h or 'h h' for help, or '$doccmd perldebug' for more help.\n\n";
69893cff
RGS
1822 } ## end else [ if ($term_pid eq '-1')
1823 } ## end unless ($runnonstop)
1824} ## end else [ if ($notty)
1825
1826# XXX This looks like a bug to me.
1827# Why copy to @ARGS and then futz with @args?
d338d6fe
PP
1828@ARGS = @ARGV;
1829for (@args) {
69893cff
RGS
1830 # Make sure backslashes before single quotes are stripped out, and
1831 # keep args unless they are numeric (XXX why?)
e22ea7cc
RF
1832 # s/\'/\\\'/g; # removed while not justified understandably
1833 # s/(.*)/'$1'/ unless /^-?[\d.]+$/; # ditto
d338d6fe
PP
1834}
1835
e22ea7cc 1836# If there was an afterinit() sub defined, call it. It will get
69893cff 1837# executed in our scope, so it can fiddle with debugger globals.
e22ea7cc 1838if ( defined &afterinit ) { # May be defined in $rcfile
69893cff 1839 &afterinit();
d338d6fe 1840}
e22ea7cc 1841
69893cff 1842# Inform us about "Stack dump during die enabled ..." in dieLevel().
43aed9ee
IZ
1843$I_m_init = 1;
1844
d338d6fe
PP
1845############################################################ Subroutines
1846
69893cff
RGS
1847=head1 SUBROUTINES
1848
1849=head2 DB
1850
1851This gigantic subroutine is the heart of the debugger. Called before every
1852statement, its job is to determine if a breakpoint has been reached, and
1853stop if so; read commands from the user, parse them, and execute
b468dcb6 1854them, and then send execution off to the next statement.
69893cff
RGS
1855
1856Note that the order in which the commands are processed is very important;
1857some commands earlier in the loop will actually alter the C<$cmd> variable
be9a9b1d 1858to create other commands to be executed later. This is all highly I<optimized>
69893cff
RGS
1859but can be confusing. Check the comments for each C<$cmd ... && do {}> to
1860see what's happening in any given command.
1861
1862=cut
1863
d338d6fe 1864sub DB {
69893cff 1865
2cbb2ee1
RGS
1866 # lock the debugger and get the thread id for the prompt
1867 lock($DBGR);
1868 my $tid;
1869 if ($ENV{PERL5DB_THREADED}) {
878090d5 1870 $tid = eval { "[".threads->tid."]" };
2cbb2ee1
RGS
1871 }
1872
69893cff 1873 # Check for whether we should be running continuously or not.
36477c24 1874 # _After_ the perl program is compiled, $single is set to 1:
e22ea7cc
RF
1875 if ( $single and not $second_time++ ) {
1876
69893cff 1877 # Options say run non-stop. Run until we get an interrupt.
e22ea7cc
RF
1878 if ($runnonstop) { # Disable until signal
1879 # If there's any call stack in place, turn off single
1880 # stepping into subs throughout the stack.
1881 for ( $i = 0 ; $i <= $stack_depth ; ) {
1882 $stack[ $i++ ] &= ~1;
1883 }
1884
69893cff 1885 # And we are now no longer in single-step mode.
e22ea7cc 1886 $single = 0;
69893cff
RGS
1887
1888 # If we simply returned at this point, we wouldn't get
1889 # the trace info. Fall on through.
e22ea7cc 1890 # return;
69893cff
RGS
1891 } ## end if ($runnonstop)
1892
e22ea7cc
RF
1893 elsif ($ImmediateStop) {
1894
1895 # We are supposed to stop here; XXX probably a break.
1896 $ImmediateStop = 0; # We've processed it; turn it off
1897 $signal = 1; # Simulate an interrupt to force
1898 # us into the command loop
69893cff
RGS
1899 }
1900 } ## end if ($single and not $second_time...
1901
1902 # If we're in single-step mode, or an interrupt (real or fake)
1903 # has occurred, turn off non-stop mode.
1904 $runnonstop = 0 if $single or $signal;
1905
1906 # Preserve current values of $@, $!, $^E, $,, $/, $\, $^W.
1907 # The code being debugged may have altered them.
d338d6fe 1908 &save;
69893cff
RGS
1909
1910 # Since DB::DB gets called after every line, we can use caller() to
1911 # figure out where we last were executing. Sneaky, eh? This works because
e22ea7cc 1912 # caller is returning all the extra information when called from the
69893cff 1913 # debugger.
e22ea7cc 1914 local ( $package, $filename, $line ) = caller;
471505cc 1915 local $filename_ini = $filename;
69893cff
RGS
1916
1917 # set up the context for DB::eval, so it can properly execute
1918 # code on behalf of the user. We add the package in so that the
1919 # code is eval'ed in the proper package (not in the debugger!).
1920 local $usercontext =
e22ea7cc 1921 '($@, $!, $^E, $,, $/, $\, $^W) = @saved;' . "package $package;";
69893cff
RGS
1922
1923 # Create an alias to the active file magical array to simplify
1924 # the code here.
e22ea7cc 1925 local (*dbline) = $main::{ '_<' . $filename };
aa057b67 1926
69893cff 1927 # Last line in the program.
471505cc 1928 local $max = $#dbline;
69893cff
RGS
1929
1930 # if we have something here, see if we should break.
e22ea7cc 1931 if ( $dbline{$line}
e09195af 1932 && _is_breakpoint_enabled($filename, $line)
e22ea7cc
RF
1933 && ( ( $stop, $action ) = split( /\0/, $dbline{$line} ) ) )
1934 {
1935
69893cff 1936 # Stop if the stop criterion says to just stop.
e22ea7cc 1937 if ( $stop eq '1' ) {
69893cff
RGS
1938 $signal |= 1;
1939 }
e22ea7cc 1940
69893cff
RGS
1941 # It's a conditional stop; eval it in the user's context and
1942 # see if we should stop. If so, remove the one-time sigil.
1943 elsif ($stop) {
e22ea7cc 1944 $evalarg = "\$DB::signal |= 1 if do {$stop}";
69893cff
RGS
1945 &eval;
1946 $dbline{$line} =~ s/;9($|\0)/$1/;
1947 }
1948 } ## end if ($dbline{$line} && ...
1949
1950 # Preserve the current stop-or-not, and see if any of the W
1951 # (watch expressions) has changed.
36477c24 1952 my $was_signal = $signal;
69893cff
RGS
1953
1954 # If we have any watch expressions ...
e22ea7cc
RF
1955 if ( $trace & 2 ) {
1956 for ( my $n = 0 ; $n <= $#to_watch ; $n++ ) {
1957 $evalarg = $to_watch[$n];
1958 local $onetimeDump; # Tell DB::eval() to not output results
69893cff
RGS
1959
1960 # Fix context DB::eval() wants to return an array, but
1961 # we need a scalar here.
e22ea7cc
RF
1962 my ($val) = join( "', '", &eval );
1963 $val = ( ( defined $val ) ? "'$val'" : 'undef' );
69893cff
RGS
1964
1965 # Did it change?
e22ea7cc
RF
1966 if ( $val ne $old_watch[$n] ) {
1967
69893cff 1968 # Yep! Show the difference, and fake an interrupt.
e22ea7cc
RF
1969 $signal = 1;
1970 print $OUT <<EOP;
405ff068 1971Watchpoint $n:\t$to_watch[$n] changed:
69893cff
RGS
1972 old value:\t$old_watch[$n]
1973 new value:\t$val
6027b9a3 1974EOP
e22ea7cc 1975 $old_watch[$n] = $val;
69893cff
RGS
1976 } ## end if ($val ne $old_watch...
1977 } ## end for (my $n = 0 ; $n <= ...
1978 } ## end if ($trace & 2)
1979
1980=head2 C<watchfunction()>
1981
1982C<watchfunction()> is a function that can be defined by the user; it is a
1983function which will be run on each entry to C<DB::DB>; it gets the
1984current package, filename, and line as its parameters.
1985
1986The watchfunction can do anything it likes; it is executing in the
1987debugger's context, so it has access to all of the debugger's internal
1988data structures and functions.
1989
1990C<watchfunction()> can control the debugger's actions. Any of the following
1991will cause the debugger to return control to the user's program after
1992C<watchfunction()> executes:
1993
1994=over 4
1995
be9a9b1d
AT
1996=item *
1997
1998Returning a false value from the C<watchfunction()> itself.
1999
2000=item *
2001
2002Altering C<$single> to a false value.
2003
2004=item *
69893cff 2005
be9a9b1d 2006Altering C<$signal> to a false value.
69893cff 2007
be9a9b1d 2008=item *
69893cff 2009
be9a9b1d 2010Turning off the C<4> bit in C<$trace> (this also disables the
69893cff
RGS
2011check for C<watchfunction()>. This can be done with
2012
2013 $trace &= ~4;
2014
2015=back
2016
2017=cut
2018
e22ea7cc 2019 # If there's a user-defined DB::watchfunction, call it with the
69893cff
RGS
2020 # current package, filename, and line. The function executes in
2021 # the DB:: package.
e22ea7cc
RF
2022 if ( $trace & 4 ) { # User-installed watch
2023 return
2024 if watchfunction( $package, $filename, $line )
2025 and not $single
2026 and not $was_signal
2027 and not( $trace & ~4 );
69893cff
RGS
2028 } ## end if ($trace & 4)
2029
e22ea7cc 2030 # Pick up any alteration to $signal in the watchfunction, and
69893cff 2031 # turn off the signal now.
6027b9a3 2032 $was_signal = $signal;
69893cff
RGS
2033 $signal = 0;
2034
2035=head2 GETTING READY TO EXECUTE COMMANDS
2036
2037The debugger decides to take control if single-step mode is on, the
2038C<t> command was entered, or the user generated a signal. If the program
2039has fallen off the end, we set things up so that entering further commands
2040won't cause trouble, and we say that the program is over.
2041
2042=cut
2043
2044 # Check to see if we should grab control ($single true,
2045 # trace set appropriately, or we got a signal).
e22ea7cc
RF
2046 if ( $single || ( $trace & 1 ) || $was_signal ) {
2047
69893cff 2048 # Yes, grab control.
e22ea7cc
RF
2049 if ($slave_editor) {
2050
69893cff 2051 # Tell the editor to update its position.
e22ea7cc
RF
2052 $position = "\032\032$filename:$line:0\n";
2053 print_lineinfo($position);
2054 }
69893cff
RGS
2055
2056=pod
2057
2058Special check: if we're in package C<DB::fake>, we've gone through the
2059C<END> block at least once. We set up everything so that we can continue
2060to enter commands and have a valid context to be in.
2061
2062=cut
2063
e22ea7cc 2064 elsif ( $package eq 'DB::fake' ) {
69893cff 2065
69893cff 2066 # Fallen off the end already.
e22ea7cc
RF
2067 $term || &setterm;
2068 print_help(<<EOP);
405ff068 2069Debugged program terminated. Use B<q> to quit or B<R> to restart,
6b27b0a0
BD
2070 use B<o> I<inhibit_exit> to avoid stopping after program termination,
2071 B<h q>, B<h R> or B<h o> to get additional info.
405ff068 2072EOP
e22ea7cc 2073
69893cff 2074 # Set the DB::eval context appropriately.
e22ea7cc
RF
2075 $package = 'main';
2076 $usercontext =
2077 '($@, $!, $^E, $,, $/, $\, $^W) = @saved;'
2078 . "package $package;"; # this won't let them modify, alas
69893cff 2079 } ## end elsif ($package eq 'DB::fake')
e219e2fb 2080
69893cff 2081=pod
e219e2fb 2082
69893cff
RGS
2083If the program hasn't finished executing, we scan forward to the
2084next executable line, print that out, build the prompt from the file and line
2085number information, and print that.
e219e2fb 2086
69893cff
RGS
2087=cut
2088
e22ea7cc
RF
2089 else {
2090
69893cff
RGS
2091 # Still somewhere in the midst of execution. Set up the
2092 # debugger prompt.
2093 $sub =~ s/\'/::/; # Swap Perl 4 package separators (') to
e22ea7cc 2094 # Perl 5 ones (sorry, we don't print Klingon
69893cff
RGS
2095 #module names)
2096
e22ea7cc
RF
2097 $prefix = $sub =~ /::/ ? "" : "${'package'}::";
2098 $prefix .= "$sub($filename:";
2099 $after = ( $dbline[$line] =~ /\n$/ ? '' : "\n" );
69893cff
RGS
2100
2101 # Break up the prompt if it's really long.
e22ea7cc
RF
2102 if ( length($prefix) > 30 ) {
2103 $position = "$prefix$line):\n$line:\t$dbline[$line]$after";
2104 $prefix = "";
2105 $infix = ":\t";
2106 }
2107 else {
2108 $infix = "):\t";
2109 $position = "$prefix$line$infix$dbline[$line]$after";
2110 }
69893cff
RGS
2111
2112 # Print current line info, indenting if necessary.
e22ea7cc
RF
2113 if ($frame) {
2114 print_lineinfo( ' ' x $stack_depth,
2115 "$line:\t$dbline[$line]$after" );
2116 }
2117 else {
611272bb 2118 depth_print_lineinfo($position);
e22ea7cc 2119 }
69893cff
RGS
2120
2121 # Scan forward, stopping at either the end or the next
2122 # unbreakable line.
e22ea7cc
RF
2123 for ( $i = $line + 1 ; $i <= $max && $dbline[$i] == 0 ; ++$i )
2124 { #{ vi
69893cff
RGS
2125
2126 # Drop out on null statements, block closers, and comments.
2127 last if $dbline[$i] =~ /^\s*[\;\}\#\n]/;
2128
2129 # Drop out if the user interrupted us.
2130 last if $signal;
2131
2132 # Append a newline if the line doesn't have one. Can happen
2133 # in eval'ed text, for instance.
e22ea7cc 2134 $after = ( $dbline[$i] =~ /\n$/ ? '' : "\n" );
69893cff
RGS
2135
2136 # Next executable line.
2137 $incr_pos = "$prefix$i$infix$dbline[$i]$after";
2138 $position .= $incr_pos;
2139 if ($frame) {
e22ea7cc 2140
69893cff 2141 # Print it indented if tracing is on.
e22ea7cc
RF
2142 print_lineinfo( ' ' x $stack_depth,
2143 "$i:\t$dbline[$i]$after" );
69893cff
RGS
2144 }
2145 else {
611272bb 2146 depth_print_lineinfo($incr_pos);
69893cff
RGS
2147 }
2148 } ## end for ($i = $line + 1 ; $i...
2149 } ## end else [ if ($slave_editor)
2150 } ## end if ($single || ($trace...
2151
2152=pod
2153
2154If there's an action to be executed for the line we stopped at, execute it.
2155If there are any preprompt actions, execute those as well.
e219e2fb
RF
2156
2157=cut
2158
69893cff
RGS
2159 # If there's an action, do it now.
2160 $evalarg = $action, &eval if $action;
e219e2fb 2161
69893cff
RGS
2162 # Are we nested another level (e.g., did we evaluate a function
2163 # that had a breakpoint in it at the debugger prompt)?
e22ea7cc
RF
2164 if ( $single || $was_signal ) {
2165
69893cff 2166 # Yes, go down a level.
e22ea7cc 2167 local $level = $level + 1;
69893cff
RGS
2168
2169 # Do any pre-prompt actions.
e22ea7cc
RF
2170 foreach $evalarg (@$pre) {
2171 &eval;
2172 }
69893cff
RGS
2173
2174 # Complain about too much recursion if we passed the limit.
e22ea7cc 2175 print $OUT $stack_depth . " levels deep in subroutine calls!\n"
69893cff
RGS
2176 if $single & 4;
2177
2178 # The line we're currently on. Set $incr to -1 to stay here
2179 # until we get a command that tells us to advance.
e22ea7cc
RF
2180 $start = $line;
2181 $incr = -1; # for backward motion.
69893cff
RGS
2182
2183 # Tack preprompt debugger actions ahead of any actual input.
e22ea7cc 2184 @typeahead = ( @$pretype, @typeahead );
69893cff
RGS
2185
2186=head2 WHERE ARE WE?
2187
2188XXX Relocate this section?
2189
2190The debugger normally shows the line corresponding to the current line of
2191execution. Sometimes, though, we want to see the next line, or to move elsewhere
2192in the file. This is done via the C<$incr>, C<$start>, and C<$max> variables.
2193
be9a9b1d
AT
2194C<$incr> controls by how many lines the I<current> line should move forward
2195after a command is executed. If set to -1, this indicates that the I<current>
69893cff
RGS
2196line shouldn't change.
2197
be9a9b1d 2198C<$start> is the I<current> line. It is used for things like knowing where to
69893cff
RGS
2199move forwards or backwards from when doing an C<L> or C<-> command.
2200
2201C<$max> tells the debugger where the last line of the current file is. It's
2202used to terminate loops most often.
2203
2204=head2 THE COMMAND LOOP
2205
2206Most of C<DB::DB> is actually a command parsing and dispatch loop. It comes
2207in two parts:
2208
2209=over 4
2210
be9a9b1d
AT
2211=item *
2212
2213The outer part of the loop, starting at the C<CMD> label. This loop
69893cff
RGS
2214reads a command and then executes it.
2215
be9a9b1d
AT
2216=item *
2217
2218The inner part of the loop, starting at the C<PIPE> label. This part
69893cff
RGS
2219is wholly contained inside the C<CMD> block and only executes a command.
2220Used to handle commands running inside a pager.
2221
2222=back
2223
2224So why have two labels to restart the loop? Because sometimes, it's easier to
2225have a command I<generate> another command and then re-execute the loop to do
2226the new command. This is faster, but perhaps a bit more convoluted.
2227
2228=cut
2229
2230 # The big command dispatch loop. It keeps running until the
2231 # user yields up control again.
2232 #
2233 # If we have a terminal for input, and we get something back
2234 # from readline(), keep on processing.
e22ea7cc
RF
2235 CMD:
2236 while (
2237
69893cff 2238 # We have a terminal, or can get one ...
e22ea7cc
RF
2239 ( $term || &setterm ),
2240
69893cff 2241 # ... and it belogs to this PID or we get one for this PID ...
e22ea7cc
RF
2242 ( $term_pid == $$ or resetterm(1) ),
2243
69893cff 2244 # ... and we got a line of command input ...
e22ea7cc
RF
2245 defined(
2246 $cmd = &readline(
2cbb2ee1 2247 "$pidprompt $tid DB"
e22ea7cc
RF
2248 . ( '<' x $level )
2249 . ( $#hist + 1 )
2250 . ( '>' x $level ) . " "
69893cff
RGS
2251 )
2252 )
2253 )
2254 {
e22ea7cc 2255
2cbb2ee1 2256 share($cmd);
69893cff
RGS
2257 # ... try to execute the input as debugger commands.
2258
2259 # Don't stop running.
2260 $single = 0;
2261
2262 # No signal is active.
2263 $signal = 0;
2264
2265 # Handle continued commands (ending with \):
e22ea7cc
RF
2266 $cmd =~ s/\\$/\n/ && do {
2267 $cmd .= &readline(" cont: ");
2268 redo CMD;
2269 };
69893cff
RGS
2270
2271=head4 The null command
2272
be9a9b1d 2273A newline entered by itself means I<re-execute the last command>. We grab the
69893cff
RGS
2274command out of C<$laststep> (where it was recorded previously), and copy it
2275back into C<$cmd> to be executed below. If there wasn't any previous command,
2276we'll do nothing below (no command will match). If there was, we also save it
2277in the command history and fall through to allow the command parsing to pick
2278it up.
2279
2280=cut
2281
2282 # Empty input means repeat the last command.
e22ea7cc
RF
2283 $cmd =~ /^$/ && ( $cmd = $laststep );
2284 chomp($cmd); # get rid of the annoying extra newline
2285 push( @hist, $cmd ) if length($cmd) > 1;
2286 push( @truehist, $cmd );
2cbb2ee1
RGS
2287 share(@hist);
2288 share(@truehist);
e22ea7cc
RF
2289
2290 # This is a restart point for commands that didn't arrive
2291 # via direct user input. It allows us to 'redo PIPE' to
2292 # re-execute command processing without reading a new command.
69893cff 2293 PIPE: {
e22ea7cc
RF
2294 $cmd =~ s/^\s+//s; # trim annoying leading whitespace
2295 $cmd =~ s/\s+$//s; # trim annoying trailing whitespace
2296 ($i) = split( /\s+/, $cmd );
69893cff
RGS
2297
2298=head3 COMMAND ALIASES
2299
2300The debugger can create aliases for commands (these are stored in the
2301C<%alias> hash). Before a command is executed, the command loop looks it up
2302in the alias hash and substitutes the contents of the alias for the command,
2303completely replacing it.
2304
2305=cut
2306
2307 # See if there's an alias for the command, and set it up if so.
e22ea7cc
RF
2308 if ( $alias{$i} ) {
2309
69893cff
RGS
2310 # Squelch signal handling; we want to keep control here
2311 # if something goes loco during the alias eval.
2312 local $SIG{__DIE__};
2313 local $SIG{__WARN__};
2314
2315 # This is a command, so we eval it in the DEBUGGER's
2316 # scope! Otherwise, we can't see the special debugger
2317 # variables, or get to the debugger's subs. (Well, we
2318 # _could_, but why make it even more complicated?)
2319 eval "\$cmd =~ $alias{$i}";
2320 if ($@) {
2321 local $\ = '';
1f874cb6 2322 print $OUT "Couldn't evaluate '$i' alias: $@";
69893cff
RGS
2323 next CMD;
2324 }
2325 } ## end if ($alias{$i})
2326
2327=head3 MAIN-LINE COMMANDS
2328
2329All of these commands work up to and after the program being debugged has
2330terminated.
2331
2332=head4 C<q> - quit
2333
2334Quit the debugger. This entails setting the C<$fall_off_end> flag, so we don't
2335try to execute further, cleaning any restart-related stuff out of the
2336environment, and executing with the last value of C<$?>.
2337
2338=cut
2339
2340 $cmd =~ /^q$/ && do {
2341 $fall_off_end = 1;
2342 clean_ENV();
2343 exit $?;
2344 };
2345
611272bb 2346=head4 C<t> - trace [n]
69893cff
RGS
2347
2348Turn tracing on or off. Inverts the appropriate bit in C<$trace> (q.v.).
611272bb 2349If level is specified, set C<$trace_to_depth>.
69893cff
RGS
2350
2351=cut
2352
611272bb
PS
2353 $cmd =~ /^t(?:\s+(\d+))?$/ && do {
2354 my $levels = $1;
e22ea7cc
RF
2355 $trace ^= 1;
2356 local $\ = '';
611272bb 2357 $trace_to_depth = $levels ? $stack_depth + $levels : 1E9;
e22ea7cc 2358 print $OUT "Trace = "
611272bb
PS
2359 . ( ( $trace & 1 )
2360 ? ( $levels ? "on (to level $trace_to_depth)" : "on" )
2361 : "off" ) . "\n";
e22ea7cc
RF
2362 next CMD;
2363 };
69893cff
RGS
2364
2365=head4 C<S> - list subroutines matching/not matching a pattern
2366
2367Walks through C<%sub>, checking to see whether or not to print the name.
2368
2369=cut
2370
e22ea7cc 2371 $cmd =~ /^S(\s+(!)?(.+))?$/ && do {
69893cff 2372
e22ea7cc 2373 $Srev = defined $2; # Reverse scan?
69893cff
RGS
2374 $Spatt = $3; # The pattern (if any) to use.
2375 $Snocheck = !defined $1; # No args - print all subs.
2376
2377 # Need to make these sane here.
e22ea7cc
RF
2378 local $\ = '';
2379 local $, = '';
69893cff
RGS
2380
2381 # Search through the debugger's magical hash of subs.
2382 # If $nocheck is true, just print the sub name.
2383 # Otherwise, check it against the pattern. We then use
2384 # the XOR trick to reverse the condition as required.
e22ea7cc
RF
2385 foreach $subname ( sort( keys %sub ) ) {
2386 if ( $Snocheck or $Srev ^ ( $subname =~ /$Spatt/ ) ) {
2387 print $OUT $subname, "\n";
2388 }
2389 }
2390 next CMD;
2391 };
69893cff
RGS
2392
2393=head4 C<X> - list variables in current package
2394
2395Since the C<V> command actually processes this, just change this to the
2396appropriate C<V> command and fall through.
2397
2398=cut
2399
e22ea7cc 2400 $cmd =~ s/^X\b/V $package/;
69893cff
RGS
2401
2402=head4 C<V> - list variables
2403
2404Uses C<dumpvar.pl> to dump out the current values for selected variables.
2405
2406=cut
2407
2408 # Bare V commands get the currently-being-debugged package
2409 # added.
e22ea7cc
RF
2410 $cmd =~ /^V$/ && do {
2411 $cmd = "V $package";
2412 };
69893cff
RGS
2413
2414 # V - show variables in package.
2415 $cmd =~ /^V\b\s*(\S+)\s*(.*)/ && do {
e22ea7cc 2416
69893cff
RGS
2417 # Save the currently selected filehandle and
2418 # force output to debugger's filehandle (dumpvar
2419 # just does "print" for output).
e22ea7cc 2420 local ($savout) = select($OUT);
69893cff
RGS
2421
2422 # Grab package name and variables to dump.
e22ea7cc
RF
2423 $packname = $1;
2424 @vars = split( ' ', $2 );
69893cff
RGS
2425
2426 # If main::dumpvar isn't here, get it.
e81465be 2427 do 'dumpvar.pl' || die $@ unless defined &main::dumpvar;
e22ea7cc
RF
2428 if ( defined &main::dumpvar ) {
2429
69893cff
RGS
2430 # We got it. Turn off subroutine entry/exit messages
2431 # for the moment, along with return values.
e22ea7cc
RF
2432 local $frame = 0;
2433 local $doret = -2;
69893cff
RGS
2434
2435 # must detect sigpipe failures - not catching
2436 # then will cause the debugger to die.
2437 eval {
2438 &main::dumpvar(
2439 $packname,
2440 defined $option{dumpDepth}
e22ea7cc
RF
2441 ? $option{dumpDepth}
2442 : -1, # assume -1 unless specified
69893cff 2443 @vars
e22ea7cc
RF
2444 );
2445 };
2446
2447 # The die doesn't need to include the $@, because
2448 # it will automatically get propagated for us.
2449 if ($@) {
2450 die unless $@ =~ /dumpvar print failed/;
2451 }
2452 } ## end if (defined &main::dumpvar)
2453 else {
2454
2455 # Couldn't load dumpvar.
2456 print $OUT "dumpvar.pl not available.\n";
2457 }
69893cff 2458
69893cff 2459 # Restore the output filehandle, and go round again.
e22ea7cc
RF
2460 select($savout);
2461 next CMD;
2462 };
69893cff
RGS
2463
2464=head4 C<x> - evaluate and print an expression
2465
2466Hands the expression off to C<DB::eval>, setting it up to print the value
2467via C<dumpvar.pl> instead of just printing it directly.
2468
2469=cut
2470
e22ea7cc
RF
2471 $cmd =~ s/^x\b/ / && do { # Remainder gets done by DB::eval()
2472 $onetimeDump = 'dump'; # main::dumpvar shows the output
69893cff
RGS
2473
2474 # handle special "x 3 blah" syntax XXX propagate
2475 # doc back to special variables.
e22ea7cc
RF
2476 if ( $cmd =~ s/^\s*(\d+)(?=\s)/ / ) {
2477 $onetimedumpDepth = $1;
2478 }
2479 };
69893cff
RGS
2480
2481=head4 C<m> - print methods
2482
2483Just uses C<DB::methods> to determine what methods are available.
2484
2485=cut
2486
e22ea7cc
RF
2487 $cmd =~ s/^m\s+([\w:]+)\s*$/ / && do {
2488 methods($1);
2489 next CMD;
2490 };
69893cff
RGS
2491
2492 # m expr - set up DB::eval to do the work
e22ea7cc
RF
2493 $cmd =~ s/^m\b/ / && do { # Rest gets done by DB::eval()
2494 $onetimeDump = 'methods'; # method output gets used there
2495 };
69893cff
RGS
2496
2497=head4 C<f> - switch files
2498
2499=cut
2500
e22ea7cc
RF
2501 $cmd =~ /^f\b\s*(.*)/ && do {
2502 $file = $1;
2503 $file =~ s/\s+$//;
69893cff
RGS
2504
2505 # help for no arguments (old-style was return from sub).
e22ea7cc
RF
2506 if ( !$file ) {
2507 print $OUT
2508 "The old f command is now the r command.\n"; # hint
2509 print $OUT "The new f command switches filenames.\n";
2510 next CMD;
2511 } ## end if (!$file)
69893cff
RGS
2512
2513 # if not in magic file list, try a close match.
e22ea7cc
RF
2514 if ( !defined $main::{ '_<' . $file } ) {
2515 if ( ($try) = grep( m#^_<.*$file#, keys %main:: ) ) {
2516 {
2517 $try = substr( $try, 2 );
1f874cb6 2518 print $OUT "Choosing $try matching '$file':\n";
e22ea7cc
RF
2519 $file = $try;
2520 }
2521 } ## end if (($try) = grep(m#^_<.*$file#...
2522 } ## end if (!defined $main::{ ...
69893cff
RGS
2523
2524 # If not successfully switched now, we failed.
e22ea7cc 2525 if ( !defined $main::{ '_<' . $file } ) {
1f874cb6 2526 print $OUT "No file matching '$file' is loaded.\n";
e22ea7cc
RF
2527 next CMD;
2528 }
69893cff 2529
e22ea7cc
RF
2530 # We switched, so switch the debugger internals around.
2531 elsif ( $file ne $filename ) {
2532 *dbline = $main::{ '_<' . $file };
2533 $max = $#dbline;
2534 $filename = $file;
2535 $start = 1;
2536 $cmd = "l";
2537 } ## end elsif ($file ne $filename)
2538
2539 # We didn't switch; say we didn't.
2540 else {
2541 print $OUT "Already in $file.\n";
2542 next CMD;
2543 }
2544 };
69893cff
RGS
2545
2546=head4 C<.> - return to last-executed line.
2547
2548We set C<$incr> to -1 to indicate that the debugger shouldn't move ahead,
2549and then we look up the line in the magical C<%dbline> hash.
2550
2551=cut
2552
2553 # . command.
e22ea7cc
RF
2554 $cmd =~ /^\.$/ && do {
2555 $incr = -1; # stay at current line
69893cff
RGS
2556
2557 # Reset everything to the old location.
e22ea7cc
RF
2558 $start = $line;
2559 $filename = $filename_ini;
2560 *dbline = $main::{ '_<' . $filename };
2561 $max = $#dbline;
69893cff
RGS
2562
2563 # Now where are we?
e22ea7cc
RF
2564 print_lineinfo($position);
2565 next CMD;
2566 };
69893cff
RGS
2567
2568=head4 C<-> - back one window
2569
2570We change C<$start> to be one window back; if we go back past the first line,
2571we set it to be the first line. We ser C<$incr> to put us back at the
2572currently-executing line, and then put a C<l $start +> (list one window from
2573C<$start>) in C<$cmd> to be executed later.
2574
2575=cut
2576
2577 # - - back a window.
e22ea7cc
RF
2578 $cmd =~ /^-$/ && do {
2579
69893cff 2580 # back up by a window; go to 1 if back too far.
e22ea7cc
RF
2581 $start -= $incr + $window + 1;
2582 $start = 1 if $start <= 0;
2583 $incr = $window - 1;
69893cff
RGS
2584
2585 # Generate and execute a "l +" command (handled below).
e22ea7cc
RF
2586 $cmd = 'l ' . ($start) . '+';
2587 };
69893cff
RGS
2588
2589=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>, {, {{>
2590
2591In Perl 5.8.0, a realignment of the commands was done to fix up a number of
2592problems, most notably that the default case of several commands destroying
2593the user's work in setting watchpoints, actions, etc. We wanted, however, to
2594retain the old commands for those who were used to using them or who preferred
2595them. At this point, we check for the new commands and call C<cmd_wrapper> to
2596deal with them instead of processing them in-line.
2597
2598=cut
2599
2600 # All of these commands were remapped in perl 5.8.0;
e22ea7cc 2601 # we send them off to the secondary dispatcher (see below).
2cbb2ee1 2602 $cmd =~ /^([aAbBeEhilLMoOPvwW]\b|[<>\{]{1,2})\s*(.*)/so && do {
e22ea7cc
RF
2603 &cmd_wrapper( $1, $2, $line );
2604 next CMD;
2605 };
69893cff
RGS
2606
2607=head4 C<y> - List lexicals in higher scope
2608
2609Uses C<PadWalker> to find the lexicals supplied as arguments in a scope
2610above the current one and then displays then using C<dumpvar.pl>.
2611
2612=cut
2613
2614 $cmd =~ /^y(?:\s+(\d*)\s*(.*))?$/ && do {
2615
2616 # See if we've got the necessary support.
2617 eval { require PadWalker; PadWalker->VERSION(0.08) }
2618 or &warn(
2619 $@ =~ /locate/
2620 ? "PadWalker module not found - please install\n"
2621 : $@
2622 )
2623 and next CMD;
2624
2625 # Load up dumpvar if we don't have it. If we can, that is.
e81465be 2626 do 'dumpvar.pl' || die $@ unless defined &main::dumpvar;
69893cff
RGS
2627 defined &main::dumpvar
2628 or print $OUT "dumpvar.pl not available.\n"
2629 and next CMD;
2630
2631 # Got all the modules we need. Find them and print them.
e22ea7cc 2632 my @vars = split( ' ', $2 || '' );
69893cff
RGS
2633
2634 # Find the pad.
e22ea7cc 2635 my $h = eval { PadWalker::peek_my( ( $1 || 0 ) + 1 ) };
69893cff
RGS
2636
2637 # Oops. Can't find it.
2638 $@ and $@ =~ s/ at .*//, &warn($@), next CMD;
2639
2640 # Show the desired vars with dumplex().
2641 my $savout = select($OUT);
2642
2643 # Have dumplex dump the lexicals.
e22ea7cc 2644 dumpvar::dumplex( $_, $h->{$_},
69893cff 2645 defined $option{dumpDepth} ? $option{dumpDepth} : -1,
e22ea7cc
RF
2646 @vars )
2647 for sort keys %$h;
69893cff
RGS
2648 select($savout);
2649 next CMD;
2650 };
2651
2652=head3 COMMANDS NOT WORKING AFTER PROGRAM ENDS
2653
2654All of the commands below this point don't work after the program being
2655debugged has ended. All of them check to see if the program has ended; this
2656allows the commands to be relocated without worrying about a 'line of
2657demarcation' above which commands can be entered anytime, and below which
2658they can't.
2659
2660=head4 C<n> - single step, but don't trace down into subs
2661
2662Done by setting C<$single> to 2, which forces subs to execute straight through
be9a9b1d 2663when entered (see C<DB::sub>). We also save the C<n> command in C<$laststep>,
69893cff
RGS
2664so a null command knows what to re-execute.
2665
2666=cut
2667
e22ea7cc 2668 # n - next
69893cff
RGS
2669 $cmd =~ /^n$/ && do {
2670 end_report(), next CMD if $finished and $level <= 1;
e22ea7cc 2671
69893cff
RGS
2672 # Single step, but don't enter subs.
2673 $single = 2;
e22ea7cc 2674
69893cff 2675 # Save for empty command (repeat last).
e22ea7cc
RF
2676 $laststep = $cmd;
2677 last CMD;
2678 };
69893cff
RGS
2679
2680=head4 C<s> - single-step, entering subs
2681
be9a9b1d 2682Sets C<$single> to 1, which causes C<DB::sub> to continue tracing inside
69893cff
RGS
2683subs. Also saves C<s> as C<$lastcmd>.
2684
2685=cut
2686
2687 # s - single step.
2688 $cmd =~ /^s$/ && do {
e22ea7cc 2689
69893cff
RGS
2690 # Get out and restart the command loop if program
2691 # has finished.
e22ea7cc
RF
2692 end_report(), next CMD if $finished and $level <= 1;
2693
69893cff 2694 # Single step should enter subs.
e22ea7cc
RF
2695 $single = 1;
2696
69893cff 2697 # Save for empty command (repeat last).
e22ea7cc
RF
2698 $laststep = $cmd;
2699 last CMD;
2700 };
69893cff
RGS
2701
2702=head4 C<c> - run continuously, setting an optional breakpoint
2703
2704Most of the code for this command is taken up with locating the optional
2705breakpoint, which is either a subroutine name or a line number. We set
2706the appropriate one-time-break in C<@dbline> and then turn off single-stepping
2707in this and all call levels above this one.
2708
2709=cut
2710
2711 # c - start continuous execution.
2712 $cmd =~ /^c\b\s*([\w:]*)\s*$/ && do {
e22ea7cc 2713
69893cff
RGS
2714 # Hey, show's over. The debugged program finished
2715 # executing already.
2716 end_report(), next CMD if $finished and $level <= 1;
2717
2718 # Capture the place to put a one-time break.
2719 $subname = $i = $1;
2720
e22ea7cc
RF
2721 # Probably not needed, since we finish an interactive
2722 # sub-session anyway...
2723 # local $filename = $filename;
2724 # local *dbline = *dbline; # XXX Would this work?!
69893cff
RGS
2725 #
2726 # The above question wonders if localizing the alias
2727 # to the magic array works or not. Since it's commented
2728 # out, we'll just leave that to speculation for now.
2729
2730 # If the "subname" isn't all digits, we'll assume it
2731 # is a subroutine name, and try to find it.
e22ea7cc
RF
2732 if ( $subname =~ /\D/ ) { # subroutine name
2733 # Qualify it to the current package unless it's
2734 # already qualified.
69893cff
RGS
2735 $subname = $package . "::" . $subname
2736 unless $subname =~ /::/;
e22ea7cc 2737
69893cff
RGS
2738 # find_sub will return "file:line_number" corresponding
2739 # to where the subroutine is defined; we call find_sub,
e22ea7cc 2740 # break up the return value, and assign it in one
69893cff 2741 # operation.
e22ea7cc 2742 ( $file, $i ) = ( find_sub($subname) =~ /^(.*):(.*)$/ );
69893cff
RGS
2743
2744 # Force the line number to be numeric.
e22ea7cc 2745 $i += 0;
69893cff
RGS
2746
2747 # If we got a line number, we found the sub.
e22ea7cc
RF
2748 if ($i) {
2749
69893cff
RGS
2750 # Switch all the debugger's internals around so
2751 # we're actually working with that file.
e22ea7cc
RF
2752 $filename = $file;
2753 *dbline = $main::{ '_<' . $filename };
2754
69893cff 2755 # Mark that there's a breakpoint in this file.
e22ea7cc
RF
2756 $had_breakpoints{$filename} |= 1;
2757
69893cff
RGS
2758 # Scan forward to the first executable line
2759 # after the 'sub whatever' line.
e22ea7cc
RF
2760 $max = $#dbline;
2761 ++$i while $dbline[$i] == 0 && $i < $max;
2762 } ## end if ($i)
69893cff
RGS
2763
2764 # We didn't find a sub by that name.
e22ea7cc
RF
2765 else {
2766 print $OUT "Subroutine $subname not found.\n";
2767 next CMD;
2768 }
2769 } ## end if ($subname =~ /\D/)
69893cff
RGS
2770
2771 # At this point, either the subname was all digits (an
2772 # absolute line-break request) or we've scanned through
2773 # the code following the definition of the sub, looking
2774 # for an executable, which we may or may not have found.
2775 #
2776 # If $i (which we set $subname from) is non-zero, we
e22ea7cc
RF
2777 # got a request to break at some line somewhere. On
2778 # one hand, if there wasn't any real subroutine name
2779 # involved, this will be a request to break in the current
2780 # file at the specified line, so we have to check to make
69893cff
RGS
2781 # sure that the line specified really is breakable.
2782 #
2783 # On the other hand, if there was a subname supplied, the
3c4b39be 2784 # preceding block has moved us to the proper file and
69893cff
RGS
2785 # location within that file, and then scanned forward
2786 # looking for the next executable line. We have to make
2787 # sure that one was found.
2788 #
2789 # On the gripping hand, we can't do anything unless the
2790 # current value of $i points to a valid breakable line.
2791 # Check that.
e22ea7cc
RF
2792 if ($i) {
2793
69893cff 2794 # Breakable?
e22ea7cc
RF
2795 if ( $dbline[$i] == 0 ) {
2796 print $OUT "Line $i not breakable.\n";
2797 next CMD;
2798 }
2799
69893cff 2800 # Yes. Set up the one-time-break sigil.
e22ea7cc
RF
2801 $dbline{$i} =~ s/($|\0)/;9$1/; # add one-time-only b.p.
2802 } ## end if ($i)
69893cff
RGS
2803
2804 # Turn off stack tracing from here up.
e22ea7cc
RF
2805 for ( $i = 0 ; $i <= $stack_depth ; ) {
2806 $stack[ $i++ ] &= ~1;
2807 }
2808 last CMD;
2809 };
69893cff
RGS
2810
2811=head4 C<r> - return from a subroutine
2812
2813For C<r> to work properly, the debugger has to stop execution again
2814immediately after the return is executed. This is done by forcing
2815single-stepping to be on in the call level above the current one. If
2816we are printing return values when a C<r> is executed, set C<$doret>
2817appropriately, and force us out of the command loop.
2818
2819=cut
2820
2821 # r - return from the current subroutine.
e22ea7cc
RF
2822 $cmd =~ /^r$/ && do {
2823
98dc9551 2824 # Can't do anything if the program's over.
e22ea7cc
RF
2825 end_report(), next CMD if $finished and $level <= 1;
2826
69893cff 2827 # Turn on stack trace.
e22ea7cc
RF
2828 $stack[$stack_depth] |= 1;
2829
69893cff 2830 # Print return value unless the stack is empty.
e22ea7cc
RF
2831 $doret = $option{PrintRet} ? $stack_depth - 1 : -2;
2832 last CMD;
2833 };
69893cff 2834
69893cff
RGS
2835=head4 C<T> - stack trace
2836
2837Just calls C<DB::print_trace>.
2838
2839=cut
2840
e22ea7cc
RF
2841 $cmd =~ /^T$/ && do {
2842 print_trace( $OUT, 1 ); # skip DB
2843 next CMD;
2844 };
69893cff
RGS
2845
2846=head4 C<w> - List window around current line.
2847
2848Just calls C<DB::cmd_w>.
2849
2850=cut
2851
e22ea7cc 2852 $cmd =~ /^w\b\s*(.*)/s && do { &cmd_w( 'w', $1 ); next CMD; };
69893cff
RGS
2853
2854=head4 C<W> - watch-expression processing.
2855
2856Just calls C<DB::cmd_W>.
2857
2858=cut
2859
e22ea7cc 2860 $cmd =~ /^W\b\s*(.*)/s && do { &cmd_W( 'W', $1 ); next CMD; };
69893cff
RGS
2861
2862=head4 C</> - search forward for a string in the source
2863
2864We take the argument and treat it as a pattern. If it turns out to be a
2865bad one, we return the error we got from trying to C<eval> it and exit.
2866If not, we create some code to do the search and C<eval> it so it can't
2867mess us up.
2868
2869=cut
2870
e22ea7cc 2871 $cmd =~ /^\/(.*)$/ && do {
69893cff
RGS
2872
2873 # The pattern as a string.
e22ea7cc 2874 $inpat = $1;
69893cff
RGS
2875
2876 # Remove the final slash.
e22ea7cc 2877 $inpat =~ s:([^\\])/$:$1:;
69893cff
RGS
2878
2879 # If the pattern isn't null ...
e22ea7cc 2880 if ( $inpat ne "" ) {
69893cff
RGS
2881
2882 # Turn of warn and die procesing for a bit.
e22ea7cc
RF
2883 local $SIG{__DIE__};
2884 local $SIG{__WARN__};
69893cff
RGS
2885
2886 # Create the pattern.
e22ea7cc
RF
2887 eval '$inpat =~ m' . "\a$inpat\a";
2888 if ( $@ ne "" ) {
2889
69893cff 2890 # Oops. Bad pattern. No biscuit.
e22ea7cc 2891 # Print the eval error and go back for more
69893cff 2892 # commands.
e22ea7cc
RF
2893 print $OUT "$@";
2894 next CMD;
2895 }
2896 $pat = $inpat;
2897 } ## end if ($inpat ne "")
69893cff
RGS
2898
2899 # Set up to stop on wrap-around.
e22ea7cc 2900 $end = $start;
69893cff
RGS
2901
2902 # Don't move off the current line.
e22ea7cc 2903 $incr = -1;
69893cff
RGS
2904
2905 # Done in eval so nothing breaks if the pattern
2906 # does something weird.
e22ea7cc
RF
2907 eval '
2908 for (;;) {
69893cff 2909 # Move ahead one line.
e22ea7cc 2910 ++$start;
69893cff
RGS
2911
2912 # Wrap if we pass the last line.
e22ea7cc 2913 $start = 1 if ($start > $max);
69893cff
RGS
2914
2915 # Stop if we have gotten back to this line again,
e22ea7cc 2916 last if ($start == $end);
69893cff
RGS
2917
2918 # A hit! (Note, though, that we are doing
2919 # case-insensitive matching. Maybe a qr//
2920 # expression would be better, so the user could
2921 # do case-sensitive matching if desired.
e22ea7cc
RF
2922 if ($dbline[$start] =~ m' . "\a$pat\a" . 'i) {
2923 if ($slave_editor) {
69893cff 2924 # Handle proper escaping in the slave.
e22ea7cc
RF
2925 print $OUT "\032\032$filename:$start:0\n";
2926 }
2927 else {
69893cff 2928 # Just print the line normally.
e22ea7cc
RF
2929 print $OUT "$start:\t",$dbline[$start],"\n";
2930 }
69893cff 2931 # And quit since we found something.
e22ea7cc
RF
2932 last;
2933 }
2934 } ';
2935
69893cff 2936 # If we wrapped, there never was a match.
e22ea7cc
RF
2937 print $OUT "/$pat/: not found\n" if ( $start == $end );
2938 next CMD;
2939 };
69893cff
RGS
2940
2941=head4 C<?> - search backward for a string in the source
2942
2943Same as for C</>, except the loop runs backwards.
2944
2945=cut
2946
2947 # ? - backward pattern search.
e22ea7cc 2948 $cmd =~ /^\?(.*)$/ && do {
69893cff
RGS
2949
2950 # Get the pattern, remove trailing question mark.
e22ea7cc
RF
2951 $inpat = $1;
2952 $inpat =~ s:([^\\])\?$:$1:;
69893cff
RGS
2953
2954 # If we've got one ...
e22ea7cc 2955 if ( $inpat ne "" ) {
69893cff
RGS
2956
2957 # Turn off die & warn handlers.
e22ea7cc
RF
2958 local $SIG{__DIE__};
2959 local $SIG{__WARN__};
2960 eval '$inpat =~ m' . "\a$inpat\a";
2961
2962 if ( $@ ne "" ) {
2963
69893cff 2964 # Ouch. Not good. Print the error.
e22ea7cc
RF
2965 print $OUT $@;
2966 next CMD;
2967 }
2968 $pat = $inpat;
69893cff 2969 } ## end if ($inpat ne "")
e22ea7cc 2970
69893cff 2971 # Where we are now is where to stop after wraparound.
e22ea7cc 2972 $end = $start;
69893cff
RGS
2973
2974 # Don't move away from this line.
e22ea7cc 2975 $incr = -1;
69893cff
RGS
2976
2977 # Search inside the eval to prevent pattern badness
2978 # from killing us.
e22ea7cc
RF
2979 eval '
2980 for (;;) {
69893cff 2981 # Back up a line.
e22ea7cc 2982 --$start;
69893cff
RGS
2983
2984 # Wrap if we pass the first line.
e22ea7cc
RF
2985
2986 $start = $max if ($start <= 0);
69893cff
RGS
2987
2988 # Quit if we get back where we started,
e22ea7cc 2989 last if ($start == $end);
69893cff
RGS
2990
2991 # Match?
e22ea7cc
RF
2992 if ($dbline[$start] =~ m' . "\a$pat\a" . 'i) {
2993 if ($slave_editor) {
69893cff 2994 # Yep, follow slave editor requirements.
e22ea7cc
RF
2995 print $OUT "\032\032$filename:$start:0\n";
2996 }
2997 else {
69893cff 2998 # Yep, just print normally.
e22ea7cc
RF
2999 print $OUT "$start:\t",$dbline[$start],"\n";
3000 }
69893cff
RGS
3001
3002 # Found, so done.
e22ea7cc
RF
3003 last;
3004 }
3005 } ';
3006
3007 # Say we failed if the loop never found anything,
3008 print $OUT "?$pat?: not found\n" if ( $start == $end );
3009 next CMD;
3010 };
69893cff
RGS
3011
3012=head4 C<$rc> - Recall command
3013
3014Manages the commands in C<@hist> (which is created if C<Term::ReadLine> reports
3015that the terminal supports history). It find the the command required, puts it
3016into C<$cmd>, and redoes the loop to execute it.
3017
3018=cut
3019
e22ea7cc
RF
3020 # $rc - recall command.
3021 $cmd =~ /^$rc+\s*(-)?(\d+)?$/ && do {
69893cff
RGS
3022
3023 # No arguments, take one thing off history.
e22ea7cc 3024 pop(@hist) if length($cmd) > 1;
69893cff 3025
e22ea7cc 3026 # Relative (- found)?
69893cff 3027 # Y - index back from most recent (by 1 if bare minus)
e22ea7cc 3028 # N - go to that particular command slot or the last
69893cff 3029 # thing if nothing following.
e22ea7cc 3030 $i = $1 ? ( $#hist - ( $2 || 1 ) ) : ( $2 || $#hist );
69893cff
RGS
3031
3032 # Pick out the command desired.
e22ea7cc 3033 $cmd = $hist[$i];
69893cff
RGS
3034
3035 # Print the command to be executed and restart the loop
3036 # with that command in the buffer.
e22ea7cc
RF
3037 print $OUT $cmd, "\n";
3038 redo CMD;
3039 };
69893cff
RGS
3040
3041=head4 C<$sh$sh> - C<system()> command
3042
3043Calls the C<DB::system()> to handle the command. This keeps the C<STDIN> and
3044C<STDOUT> from getting messed up.
3045
3046=cut
3047
3048 # $sh$sh - run a shell command (if it's all ASCII).
3049 # Can't run shell commands with Unicode in the debugger, hmm.
e22ea7cc
RF
3050 $cmd =~ /^$sh$sh\s*([\x00-\xff]*)/ && do {
3051
69893cff 3052 # System it.
e22ea7cc
RF
3053 &system($1);
3054 next CMD;
3055 };
69893cff
RGS
3056
3057=head4 C<$rc I<pattern> $rc> - Search command history
3058
3059Another command to manipulate C<@hist>: this one searches it with a pattern.
be9a9b1d 3060If a command is found, it is placed in C<$cmd> and executed via C<redo>.
69893cff
RGS
3061
3062=cut
3063
e22ea7cc
RF
3064 # $rc pattern $rc - find a command in the history.
3065 $cmd =~ /^$rc([^$rc].*)$/ && do {
3066
69893cff 3067 # Create the pattern to use.
e22ea7cc 3068 $pat = "^$1";
69893cff
RGS
3069
3070 # Toss off last entry if length is >1 (and it always is).
e22ea7cc 3071 pop(@hist) if length($cmd) > 1;
69893cff
RGS
3072
3073 # Look backward through the history.
e22ea7cc
RF
3074 for ( $i = $#hist ; $i ; --$i ) {
3075
69893cff 3076 # Stop if we find it.
e22ea7cc
RF
3077 last if $hist[$i] =~ /$pat/;
3078 }
3079
3080 if ( !$i ) {
69893cff 3081
69893cff 3082 # Never found it.
e22ea7cc
RF
3083 print $OUT "No such command!\n\n";
3084 next CMD;
3085 }
69893cff
RGS
3086
3087 # Found it. Put it in the buffer, print it, and process it.
e22ea7cc
RF
3088 $cmd = $hist[$i];
3089 print $OUT $cmd, "\n";
3090 redo CMD;
3091 };
69893cff
RGS
3092
3093=head4 C<$sh> - Invoke a shell
3094
3095Uses C<DB::system> to invoke a shell.
3096
3097=cut
3098
3099 # $sh - start a shell.
e22ea7cc
RF
3100 $cmd =~ /^$sh$/ && do {
3101
69893cff
RGS
3102 # Run the user's shell. If none defined, run Bourne.
3103 # We resume execution when the shell terminates.
e22ea7cc
RF
3104 &system( $ENV{SHELL} || "/bin/sh" );
3105 next CMD;
3106 };
69893cff
RGS
3107
3108=head4 C<$sh I<command>> - Force execution of a command in a shell
3109
3110Like the above, but the command is passed to the shell. Again, we use
3111C<DB::system> to avoid problems with C<STDIN> and C<STDOUT>.
3112
3113=cut
3114
3115 # $sh command - start a shell and run a command in it.
e22ea7cc
RF
3116 $cmd =~ /^$sh\s*([\x00-\xff]*)/ && do {
3117
3118 # XXX: using csh or tcsh destroys sigint retvals!
3119 #&system($1); # use this instead
69893cff
RGS
3120
3121 # use the user's shell, or Bourne if none defined.
e22ea7cc
RF
3122 &system( $ENV{SHELL} || "/bin/sh", "-c", $1 );
3123 next CMD;
3124 };
69893cff
RGS
3125
3126=head4 C<H> - display commands in history
3127
3128Prints the contents of C<@hist> (if any).
3129
3130=cut
3131
7fddc82f
RF
3132 $cmd =~ /^H\b\s*\*/ && do {
3133 @hist = @truehist = ();
3134 print $OUT "History cleansed\n";
3135 next CMD;
3136 };
e22ea7cc
RF
3137
3138 $cmd =~ /^H\b\s*(-(\d+))?/ && do {
3139
3140 # Anything other than negative numbers is ignored by
69893cff 3141 # the (incorrect) pattern, so this test does nothing.
e22ea7cc 3142 $end = $2 ? ( $#hist - $2 ) : 0;
69893cff
RGS
3143
3144 # Set to the minimum if less than zero.
e22ea7cc 3145 $hist = 0 if $hist < 0;
69893cff 3146
e22ea7cc 3147 # Start at the end of the array.
69893cff
RGS
3148 # Stay in while we're still above the ending value.
3149 # Tick back by one each time around the loop.
e22ea7cc 3150 for ( $i = $#hist ; $i > $end ; $i-- ) {
69893cff
RGS
3151
3152 # Print the command unless it has no arguments.
e22ea7cc
RF
3153 print $OUT "$i: ", $hist[$i], "\n"
3154 unless $hist[$i] =~ /^.?$/;
3155 }
3156 next CMD;
3157 };
69893cff
RGS
3158
3159=head4 C<man, doc, perldoc> - look up documentation
3160
3161Just calls C<runman()> to print the appropriate document.
3162
3163=cut
3164
e22ea7cc
RF
3165 # man, perldoc, doc - show manual pages.
3166 $cmd =~ /^(?:man|(?:perl)?doc)\b(?:\s+([^(]*))?$/ && do {
3167 runman($1);
3168 next CMD;
3169 };
69893cff
RGS
3170
3171=head4 C<p> - print
3172
3173Builds a C<print EXPR> expression in the C<$cmd>; this will get executed at
3174the bottom of the loop.
3175
3176=cut
3177
3178 # p - print (no args): print $_.
e22ea7cc 3179 $cmd =~ s/^p$/print {\$DB::OUT} \$_/;
69893cff
RGS
3180
3181 # p - print the given expression.
e22ea7cc 3182 $cmd =~ s/^p\b/print {\$DB::OUT} /;
69893cff
RGS
3183
3184=head4 C<=> - define command alias
3185
3186Manipulates C<%alias> to add or list command aliases.
3187
3188=cut
3189
e22ea7cc
RF
3190 # = - set up a command alias.
3191 $cmd =~ s/^=\s*// && do {
3192 my @keys;
3193 if ( length $cmd == 0 ) {
3194
69893cff 3195 # No args, get current aliases.
e22ea7cc
RF
3196 @keys = sort keys %alias;
3197 }
3198 elsif ( my ( $k, $v ) = ( $cmd =~ /^(\S+)\s+(\S.*)/ ) ) {
3199
69893cff
RGS
3200 # Creating a new alias. $k is alias name, $v is
3201 # alias value.
3202
e22ea7cc
RF
3203 # can't use $_ or kill //g state
3204 for my $x ( $k, $v ) {
3205
3206 # Escape "alarm" characters.
3207 $x =~ s/\a/\\a/g;
3208 }
69893cff
RGS
3209
3210 # Substitute key for value, using alarm chars
e22ea7cc 3211 # as separators (which is why we escaped them in
69893cff 3212 # the command).
e22ea7cc 3213 $alias{$k} = "s\a$k\a$v\a";
69893cff
RGS
3214
3215 # Turn off standard warn and die behavior.
e22ea7cc
RF
3216 local $SIG{__DIE__};
3217 local $SIG{__WARN__};
69893cff
RGS
3218
3219 # Is it valid Perl?
e22ea7cc
RF
3220 unless ( eval "sub { s\a$k\a$v\a }; 1" ) {
3221
69893cff 3222 # Nope. Bad alias. Say so and get out.
e22ea7cc
RF
3223 print $OUT "Can't alias $k to $v: $@\n";
3224 delete $alias{$k};
3225 next CMD;
3226 }
3227
69893cff 3228 # We'll only list the new one.
e22ea7cc 3229 @keys = ($k);
69893cff
RGS
3230 } ## end elsif (my ($k, $v) = ($cmd...
3231
3232 # The argument is the alias to list.
e22ea7cc
RF
3233 else {
3234 @keys = ($cmd);
3235 }
69893cff
RGS
3236
3237 # List aliases.
e22ea7cc
RF
3238 for my $k (@keys) {
3239
98dc9551 3240 # Messy metaquoting: Trim the substitution code off.
69893cff
RGS
3241 # We use control-G as the delimiter because it's not
3242 # likely to appear in the alias.
e22ea7cc
RF
3243 if ( ( my $v = $alias{$k} ) =~ s\as\a$k\a(.*)\a$\a1\a ) {
3244
69893cff 3245 # Print the alias.
e22ea7cc
RF
3246 print $OUT "$k\t= $1\n";
3247 }
3248 elsif ( defined $alias{$k} ) {
3249
69893cff 3250 # Couldn't trim it off; just print the alias code.
e22ea7cc
RF
3251 print $OUT "$k\t$alias{$k}\n";
3252 }
3253 else {
3254
69893cff 3255 # No such, dude.
e22ea7cc
RF
3256 print "No alias for $k\n";
3257 }
69893cff 3258 } ## end for my $k (@keys)
e22ea7cc
RF
3259 next CMD;
3260 };
69893cff
RGS
3261
3262=head4 C<source> - read commands from a file.
3263
3264Opens a lexical filehandle and stacks it on C<@cmdfhs>; C<DB::readline> will
3265pick it up.
3266
3267=cut
3268
e22ea7cc
RF
3269 # source - read commands from a file (or pipe!) and execute.
3270 $cmd =~ /^source\s+(.*\S)/ && do {
3271 if ( open my $fh, $1 ) {
3272
69893cff 3273 # Opened OK; stick it in the list of file handles.
e22ea7cc
RF
3274 push @cmdfhs, $fh;
3275 }
3276 else {
3277
3278 # Couldn't open it.
1f874cb6 3279 &warn("Can't execute '$1': $!\n");
e22ea7cc
RF
3280 }
3281 next CMD;
3282 };
69893cff 3283
e09195af
SF
3284 $cmd =~ /^(enable|disable)\s+(\S+)\s*$/ && do {
3285 my ($cmd, $position) = ($1, $2);
3286
3287 my ($fn, $line_num);
3288 if ($position =~ m{\A\d+\z})
3289 {
3290 $fn = $filename;
3291 $line_num = $position;
3292 }
3293 elsif ($position =~ m{\A(.*):(\d+)\z})
3294 {
3295 ($fn, $line_num) = ($1, $2);
3296 }
3297 else
3298 {
3299 &warn("Wrong spec for enable/disable argument.\n");
3300 }
3301
3302 if (defined($fn)) {
3303 if (_has_breakpoint_data_ref($fn, $line_num)) {
3304 _set_breakpoint_enabled_status($fn, $line_num,
3305 ($cmd eq 'enable' ? 1 : '')
3306 );
3307 }
3308 else {
3309 &warn("No breakpoint set at ${fn}:${line_num}\n");
3310 }
3311 }
3312
3313 next CMD;
3314 };
3315
69893cff
RGS
3316=head4 C<save> - send current history to a file
3317
3318Takes the complete history, (not the shrunken version you see with C<H>),
3319and saves it to the given filename, so it can be replayed using C<source>.
3320
3321Note that all C<^(save|source)>'s are commented out with a view to minimise recursion.
3322
3323=cut
3324
3325 # save source - write commands to a file for later use
3326 $cmd =~ /^save\s*(.*)$/ && do {
e22ea7cc
RF
3327 my $file = $1 || '.perl5dbrc'; # default?
3328 if ( open my $fh, "> $file" ) {
3329
3330 # chomp to remove extraneous newlines from source'd files
3331 chomp( my @truelist =
3332 map { m/^\s*(save|source)/ ? "#$_" : $_ }
3333 @truehist );
3334 print $fh join( "\n", @truelist );
69893cff 3335 print "commands saved in $file\n";
e22ea7cc
RF
3336 }
3337 else {
69893cff
RGS
3338 &warn("Can't save debugger commands in '$1': $!\n");
3339 }
3340 next CMD;
3341 };
3342
7fddc82f
RF
3343=head4 C<R> - restart
3344
3345Restart the debugger session.
3346
3347=head4 C<rerun> - rerun the current session
3348
3349Return to any given position in the B<true>-history list
3350
3351=cut
3352
3353 # R - restart execution.
3354 # rerun - controlled restart execution.
3355 $cmd =~ /^(R|rerun\s*(.*))$/ && do {
3356 my @args = ($1 eq 'R' ? restart() : rerun($2));
3357
ca28b541
AP
3358 # Close all non-system fds for a clean restart. A more
3359 # correct method would be to close all fds that were not
3360 # open when the process started, but this seems to be
3361 # hard. See "debugger 'R'estart and open database
3362 # connections" on p5p.
3363
47d3bbda 3364 my $max_fd = 1024; # default if POSIX can't be loaded
ca28b541 3365 if (eval { require POSIX }) {
5332cc68 3366 eval { $max_fd = POSIX::sysconf(POSIX::_SC_OPEN_MAX()) };
ca28b541
AP
3367 }
3368
3369 if (defined $max_fd) {
3370 foreach ($^F+1 .. $max_fd-1) {
3371 next unless open FD_TO_CLOSE, "<&=$_";
3372 close(FD_TO_CLOSE);
3373 }
3374 }
3375
7fddc82f
RF
3376 # And run Perl again. We use exec() to keep the
3377 # PID stable (and that way $ini_pids is still valid).
3378 exec(@args) || print $OUT "exec failed: $!\n";
3379
3380 last CMD;
3381 };
3382
69893cff
RGS
3383=head4 C<|, ||> - pipe output through the pager.
3384
be9a9b1d 3385For C<|>, we save C<OUT> (the debugger's output filehandle) and C<STDOUT>
69893cff
RGS
3386(the program's standard output). For C<||>, we only save C<OUT>. We open a
3387pipe to the pager (restoring the output filehandles if this fails). If this
3388is the C<|> command, we also set up a C<SIGPIPE> handler which will simply
3389set C<$signal>, sending us back into the debugger.
3390
3391We then trim off the pipe symbols and C<redo> the command loop at the
3392C<PIPE> label, causing us to evaluate the command in C<$cmd> without
3393reading another.
3394
3395=cut
3396
3397 # || - run command in the pager, with output to DB::OUT.
e22ea7cc
RF
3398 $cmd =~ /^\|\|?\s*[^|]/ && do {
3399 if ( $pager =~ /^\|/ ) {
3400
69893cff 3401 # Default pager is into a pipe. Redirect I/O.
e22ea7cc
RF
3402 open( SAVEOUT, ">&STDOUT" )
3403 || &warn("Can't save STDOUT");
3404 open( STDOUT, ">&OUT" )
3405 || &warn("Can't redirect STDOUT");
69893cff 3406 } ## end if ($pager =~ /^\|/)
e22ea7cc
RF
3407 else {
3408
69893cff 3409 # Not into a pipe. STDOUT is safe.
e22ea7cc
RF
3410 open( SAVEOUT, ">&OUT" ) || &warn("Can't save DB::OUT");
3411 }
69893cff
RGS
3412
3413 # Fix up environment to record we have less if so.
e22ea7cc
RF
3414 fix_less();
3415
3416 unless ( $piped = open( OUT, $pager ) ) {
69893cff 3417
69893cff 3418 # Couldn't open pipe to pager.
1f874cb6 3419 &warn("Can't pipe output to '$pager'");
e22ea7cc
RF
3420 if ( $pager =~ /^\|/ ) {
3421
69893cff 3422 # Redirect I/O back again.
e22ea7cc
RF
3423 open( OUT, ">&STDOUT" ) # XXX: lost message
3424 || &warn("Can't restore DB::OUT");
3425 open( STDOUT, ">&SAVEOUT" )
3426 || &warn("Can't restore STDOUT");
3427 close(SAVEOUT);
69893cff 3428 } ## end if ($pager =~ /^\|/)
e22ea7cc
RF
3429 else {
3430
69893cff 3431 # Redirect I/O. STDOUT already safe.
e22ea7cc
RF
3432 open( OUT, ">&STDOUT" ) # XXX: lost message
3433 || &warn("Can't restore DB::OUT");
3434 }
3435 next CMD;
69893cff
RGS
3436 } ## end unless ($piped = open(OUT,...
3437
3438 # Set up broken-pipe handler if necessary.
e22ea7cc
RF
3439 $SIG{PIPE} = \&DB::catch
3440 if $pager =~ /^\|/
3441 && ( "" eq $SIG{PIPE} || "DEFAULT" eq $SIG{PIPE} );
69893cff
RGS
3442
3443 # Save current filehandle, unbuffer out, and put it back.
e22ea7cc
RF
3444 $selected = select(OUT);
3445 $| = 1;
69893cff
RGS
3446
3447 # Don't put it back if pager was a pipe.
e22ea7cc 3448 select($selected), $selected = "" unless $cmd =~ /^\|\|/;
69893cff
RGS
3449
3450 # Trim off the pipe symbols and run the command now.
e22ea7cc
RF
3451 $cmd =~ s/^\|+\s*//;
3452 redo PIPE;
3453 };
69893cff
RGS
3454
3455=head3 END OF COMMAND PARSING
3456
3457Anything left in C<$cmd> at this point is a Perl expression that we want to
3458evaluate. We'll always evaluate in the user's context, and fully qualify
3459any variables we might want to address in the C<DB> package.
3460
3461=cut
3462
3463 # t - turn trace on.
611272bb
PS
3464 $cmd =~ s/^t\s+(\d+)?/\$DB::trace |= 1;\n/ && do {
3465 $trace_to_depth = $1 ? $stack_depth||0 + $1 : 1E9;
3466 };
69893cff
RGS
3467
3468 # s - single-step. Remember the last command was 's'.
e22ea7cc 3469 $cmd =~ s/^s\s/\$DB::single = 1;\n/ && do { $laststep = 's' };
69893cff
RGS
3470
3471 # n - single-step, but not into subs. Remember last command
e22ea7cc
RF
3472 # was 'n'.
3473 $cmd =~ s/^n\s/\$DB::single = 2;\n/ && do { $laststep = 'n' };
69893cff 3474
e22ea7cc 3475 } # PIPE:
69893cff 3476
e22ea7cc 3477 # Make sure the flag that says "the debugger's running" is
69893cff 3478 # still on, to make sure we get control again.
e22ea7cc 3479 $evalarg = "\$^D = \$^D | \$DB::db_stop;\n$cmd";
69893cff
RGS
3480
3481 # Run *our* eval that executes in the caller's context.
e22ea7cc 3482 &eval;
69893cff
RGS
3483
3484 # Turn off the one-time-dump stuff now.
e22ea7cc
RF
3485 if ($onetimeDump) {
3486 $onetimeDump = undef;
69893cff 3487 $onetimedumpDepth = undef;
e22ea7cc
RF
3488 }
3489 elsif ( $term_pid == $$ ) {
c7e68384
IZ
3490 eval { # May run under miniperl, when not available...
3491 STDOUT->flush();
3492 STDERR->flush();
3493 };
e22ea7cc 3494
69893cff 3495 # XXX If this is the master pid, print a newline.
e22ea7cc
RF
3496 print $OUT "\n";
3497 }
3498 } ## end while (($term || &setterm...
69893cff
RGS
3499
3500=head3 POST-COMMAND PROCESSING
3501
3502After each command, we check to see if the command output was piped anywhere.
3503If so, we go through the necessary code to unhook the pipe and go back to
3504our standard filehandles for input and output.
3505
3506=cut
3507
e22ea7cc 3508 continue { # CMD:
69893cff
RGS
3509
3510 # At the end of every command:
e22ea7cc
RF
3511 if ($piped) {
3512
69893cff 3513 # Unhook the pipe mechanism now.
e22ea7cc
RF
3514 if ( $pager =~ /^\|/ ) {
3515
69893cff 3516 # No error from the child.
e22ea7cc 3517 $? = 0;
69893cff 3518
e22ea7cc
RF
3519 # we cannot warn here: the handle is missing --tchrist
3520 close(OUT) || print SAVEOUT "\nCan't close DB::OUT\n";
69893cff 3521
e22ea7cc 3522 # most of the $? crud was coping with broken cshisms
69893cff 3523 # $? is explicitly set to 0, so this never runs.
e22ea7cc 3524 if ($?) {
1f874cb6 3525 print SAVEOUT "Pager '$pager' failed: ";
e22ea7cc
RF
3526 if ( $? == -1 ) {
3527 print SAVEOUT "shell returned -1\n";
3528 }
3529 elsif ( $? >> 8 ) {
3530 print SAVEOUT ( $? & 127 )
3531 ? " (SIG#" . ( $? & 127 ) . ")"
3532 : "", ( $? & 128 ) ? " -- core dumped" : "", "\n";
3533 }
3534 else {
3535 print SAVEOUT "status ", ( $? >> 8 ), "\n";
3536 }
69893cff
RGS
3537 } ## end if ($?)
3538
e22ea7cc 3539 # Reopen filehandle for our output (if we can) and
69893cff 3540 # restore STDOUT (if we can).
e22ea7cc
RF
3541 open( OUT, ">&STDOUT" ) || &warn("Can't restore DB::OUT");
3542 open( STDOUT, ">&SAVEOUT" )
3543 || &warn("Can't restore STDOUT");
69893cff
RGS
3544
3545 # Turn off pipe exception handler if necessary.
e22ea7cc 3546 $SIG{PIPE} = "DEFAULT" if $SIG{PIPE} eq \&DB::catch;
69893cff 3547
e22ea7cc
RF
3548 # Will stop ignoring SIGPIPE if done like nohup(1)
3549 # does SIGINT but Perl doesn't give us a choice.
69893cff 3550 } ## end if ($pager =~ /^\|/)
e22ea7cc
RF
3551 else {
3552
69893cff 3553 # Non-piped "pager". Just restore STDOUT.
e22ea7cc
RF
3554 open( OUT, ">&SAVEOUT" ) || &warn("Can't restore DB::OUT");
3555 }
69893cff
RGS
3556
3557 # Close filehandle pager was using, restore the normal one
3558 # if necessary,
3559 close(SAVEOUT);
e22ea7cc 3560 select($selected), $selected = "" unless $selected eq "";
69893cff
RGS
3561
3562 # No pipes now.
e22ea7cc 3563 $piped = "";
69893cff 3564 } ## end if ($piped)
e22ea7cc 3565 } # CMD:
69893cff
RGS
3566
3567=head3 COMMAND LOOP TERMINATION
3568
3569When commands have finished executing, we come here. If the user closed the
3570input filehandle, we turn on C<$fall_off_end> to emulate a C<q> command. We
3571evaluate any post-prompt items. We restore C<$@>, C<$!>, C<$^E>, C<$,>, C<$/>,
3572C<$\>, and C<$^W>, and return a null list as expected by the Perl interpreter.
3573The interpreter will then execute the next line and then return control to us
3574again.
3575
3576=cut
3577
3578 # No more commands? Quit.
1f874cb6 3579 $fall_off_end = 1 unless defined $cmd; # Emulate 'q' on EOF
69893cff
RGS
3580
3581 # Evaluate post-prompt commands.
e22ea7cc
RF
3582 foreach $evalarg (@$post) {
3583 &eval;
3584 }
3585 } # if ($single || $signal)
69893cff
RGS
3586
3587 # Put the user's globals back where you found them.
e22ea7cc 3588 ( $@, $!, $^E, $,, $/, $\, $^W ) = @saved;
69893cff
RGS
3589 ();
3590} ## end sub DB
3591
3592# The following code may be executed now:
3593# BEGIN {warn 4}
3594
3595=head2 sub
3596
3597C<sub> is called whenever a subroutine call happens in the program being
3598debugged. The variable C<$DB::sub> contains the name of the subroutine
3599being called.
3600
3601The core function of this subroutine is to actually call the sub in the proper
3602context, capturing its output. This of course causes C<DB::DB> to get called
3603again, repeating until the subroutine ends and returns control to C<DB::sub>
3604again. Once control returns, C<DB::sub> figures out whether or not to dump the
3605return value, and returns its captured copy of the return value as its own
3606return value. The value then feeds back into the program being debugged as if
3607C<DB::sub> hadn't been there at all.
3608
3609C<sub> does all the work of printing the subroutine entry and exit messages
3610enabled by setting C<$frame>. It notes what sub the autoloader got called for,
3611and also prints the return value if needed (for the C<r> command and if
3612the 16 bit is set in C<$frame>).
3613
3614It also tracks the subroutine call depth by saving the current setting of
3615C<$single> in the C<@stack> package global; if this exceeds the value in
3616C<$deep>, C<sub> automatically turns on printing of the current depth by
be9a9b1d 3617setting the C<4> bit in C<$single>. In any case, it keeps the current setting
69893cff
RGS
3618of stop/don't stop on entry to subs set as it currently is set.
3619
3620=head3 C<caller()> support
3621
3622If C<caller()> is called from the package C<DB>, it provides some
3623additional data, in the following order:
3624
3625=over 4
3626
3627=item * C<$package>
3628
3629The package name the sub was in
3630
3631=item * C<$filename>
3632
3633The filename it was defined in
3634
3635=item * C<$line>
3636
3637The line number it was defined on
3638
3639=item * C<$subroutine>
3640
be9a9b1d 3641The subroutine name; C<(eval)> if an C<eval>().
69893cff
RGS
3642
3643=item * C<$hasargs>
3644
36451 if it has arguments, 0 if not
3646
3647=item * C<$wantarray>
3648
36491 if array context, 0 if scalar context
3650
3651=item * C<$evaltext>
3652
3653The C<eval>() text, if any (undefined for C<eval BLOCK>)
3654
3655=item * C<$is_require>
3656
3657frame was created by a C<use> or C<require> statement
3658
3659=item * C<$hints>
3660
3661pragma information; subject to change between versions
3662
3663=item * C<$bitmask>
3664
be9a9b1d 3665pragma information; subject to change between versions
69893cff
RGS
3666
3667=item * C<@DB::args>
3668
3669arguments with which the subroutine was invoked
3670
3671=back
3672
3673=cut
d338d6fe 3674
d12a4851 3675sub sub {
b7bfa855
B
3676 # Do not use a regex in this subroutine -> results in corrupted memory
3677 # See: [perl #66110]