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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
176The array C<@{$main::{'_<'.$filename}}> (aliased locally to C<@dbline> via glob
177assignment) contains the text from C<$filename>, with each element
178corresponding to a single line of C<$filename>.
179
180The hash C<%{'_<'.$filename}> (aliased locally to C<%dbline> via glob
181assignment) contains breakpoints and actions. The keys are line numbers;
182you can set individual values, but not the whole hash. The Perl interpreter
183uses this hash to determine where breakpoints have been set. Any true value is
be9a9b1d 184considered to be a breakpoint; C<perl5db.pl> uses C<$break_condition\0$action>.
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185Values are magical in numeric context: 1 if the line is breakable, 0 if not.
186
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187The scalar C<${"_<$filename"}> simply contains the string C<_<$filename>.
188This is also the case for evaluated strings that contain subroutines, or
189which are currently being executed. The $filename for C<eval>ed strings looks
190like C<(eval 34)> or C<(re_eval 19)>.
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191
192=head1 DEBUGGER STARTUP
193
194When C<perl5db.pl> starts, it reads an rcfile (C<perl5db.ini> for
195non-interactive sessions, C<.perldb> for interactive ones) that can set a number
196of options. In addition, this file may define a subroutine C<&afterinit>
197that will be executed (in the debugger's context) after the debugger has
198initialized itself.
199
200Next, it checks the C<PERLDB_OPTS> environment variable and treats its
be9a9b1d 201contents as the argument of a C<o> command in the debugger.
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202
203=head2 STARTUP-ONLY OPTIONS
204
205The following options can only be specified at startup.
206To set them in your rcfile, add a call to
207C<&parse_options("optionName=new_value")>.
208
209=over 4
210
211=item * TTY
212
213the TTY to use for debugging i/o.
214
215=item * noTTY
216
217if set, goes in NonStop mode. On interrupt, if TTY is not set,
b0e77abc 218uses the value of noTTY or F<$HOME/.perldbtty$$> to find TTY using
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219Term::Rendezvous. Current variant is to have the name of TTY in this
220file.
221
222=item * ReadLine
223
5561b870 224if false, a dummy ReadLine is used, so you can debug
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225ReadLine applications.
226
227=item * NonStop
228
229if true, no i/o is performed until interrupt.
230
231=item * LineInfo
232
233file or pipe to print line number info to. If it is a
234pipe, a short "emacs like" message is used.
235
236=item * RemotePort
237
238host:port to connect to on remote host for remote debugging.
239
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240=item * HistFile
241
242file to store session history to. There is no default and so no
243history file is written unless this variable is explicitly set.
244
245=item * HistSize
246
247number of commands to store to the file specified in C<HistFile>.
248Default is 100.
249
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250=back
251
252=head3 SAMPLE RCFILE
253
254 &parse_options("NonStop=1 LineInfo=db.out");
255 sub afterinit { $trace = 1; }
256
257The script will run without human intervention, putting trace
258information into C<db.out>. (If you interrupt it, you had better
be9a9b1d 259reset C<LineInfo> to something I<interactive>!)
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260
261=head1 INTERNALS DESCRIPTION
262
263=head2 DEBUGGER INTERFACE VARIABLES
264
265Perl supplies the values for C<%sub>. It effectively inserts
be9a9b1d 266a C<&DB::DB();> in front of each place that can have a
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267breakpoint. At each subroutine call, it calls C<&DB::sub> with
268C<$DB::sub> set to the called subroutine. It also inserts a C<BEGIN
269{require 'perl5db.pl'}> before the first line.
270
271After each C<require>d file is compiled, but before it is executed, a
272call to C<&DB::postponed($main::{'_<'.$filename})> is done. C<$filename>
273is the expanded name of the C<require>d file (as found via C<%INC>).
274
275=head3 IMPORTANT INTERNAL VARIABLES
276
277=head4 C<$CreateTTY>
278
279Used to control when the debugger will attempt to acquire another TTY to be
280used for input.
281
282=over
283
284=item * 1 - on C<fork()>
285
286=item * 2 - debugger is started inside debugger
287
288=item * 4 - on startup
289
290=back
291
292=head4 C<$doret>
293
294The value -2 indicates that no return value should be printed.
295Any other positive value causes C<DB::sub> to print return values.
296
297=head4 C<$evalarg>
298
299The item to be eval'ed by C<DB::eval>. Used to prevent messing with the current
300contents of C<@_> when C<DB::eval> is called.
301
302=head4 C<$frame>
303
304Determines what messages (if any) will get printed when a subroutine (or eval)
305is entered or exited.
306
307=over 4
308
309=item * 0 - No enter/exit messages
310
be9a9b1d 311=item * 1 - Print I<entering> messages on subroutine entry
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312
313=item * 2 - Adds exit messages on subroutine exit. If no other flag is on, acts like 1+2.
314
be9a9b1d 315=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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316
317=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.
318
319=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.
320
321=back
322
be9a9b1d 323To get everything, use C<$frame=30> (or C<o f=30> as a debugger command).
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324The debugger internally juggles the value of C<$frame> during execution to
325protect external modules that the debugger uses from getting traced.
326
327=head4 C<$level>
328
329Tracks current debugger nesting level. Used to figure out how many
330C<E<lt>E<gt>> pairs to surround the line number with when the debugger
331outputs a prompt. Also used to help determine if the program has finished
332during command parsing.
333
334=head4 C<$onetimeDump>
335
336Controls what (if anything) C<DB::eval()> will print after evaluating an
337expression.
338
339=over 4
340
341=item * C<undef> - don't print anything
342
343=item * C<dump> - use C<dumpvar.pl> to display the value returned
344
345=item * C<methods> - print the methods callable on the first item returned
346
347=back
348
349=head4 C<$onetimeDumpDepth>
350
be9a9b1d 351Controls how far down C<dumpvar.pl> will go before printing C<...> while
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352dumping a structure. Numeric. If C<undef>, print all levels.
353
354=head4 C<$signal>
355
356Used to track whether or not an C<INT> signal has been detected. C<DB::DB()>,
357which is called before every statement, checks this and puts the user into
358command mode if it finds C<$signal> set to a true value.
359
360=head4 C<$single>
361
362Controls behavior during single-stepping. Stacked in C<@stack> on entry to
363each subroutine; popped again at the end of each subroutine.
364
365=over 4
366
367=item * 0 - run continuously.
368
be9a9b1d 369=item * 1 - single-step, go into subs. The C<s> command.
69893cff 370
be9a9b1d 371=item * 2 - single-step, don't go into subs. The C<n> command.
69893cff 372
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373=item * 4 - print current sub depth (turned on to force this when C<too much
374recursion> occurs.
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375
376=back
377
378=head4 C<$trace>
379
380Controls the output of trace information.
381
382=over 4
383
384=item * 1 - The C<t> command was entered to turn on tracing (every line executed is printed)
385
386=item * 2 - watch expressions are active
387
388=item * 4 - user defined a C<watchfunction()> in C<afterinit()>
389
390=back
391
392=head4 C<$slave_editor>
393
3941 if C<LINEINFO> was directed to a pipe; 0 otherwise.
395
396=head4 C<@cmdfhs>
397
398Stack of filehandles that C<DB::readline()> will read commands from.
399Manipulated by the debugger's C<source> command and C<DB::readline()> itself.
400
401=head4 C<@dbline>
402
403Local alias to the magical line array, C<@{$main::{'_<'.$filename}}> ,
404supplied by the Perl interpreter to the debugger. Contains the source.
405
406=head4 C<@old_watch>
407
408Previous values of watch expressions. First set when the expression is
409entered; reset whenever the watch expression changes.
410
411=head4 C<@saved>
412
413Saves important globals (C<$@>, C<$!>, C<$^E>, C<$,>, C<$/>, C<$\>, C<$^W>)
414so that the debugger can substitute safe values while it's running, and
415restore them when it returns control.
416
417=head4 C<@stack>
418
419Saves the current value of C<$single> on entry to a subroutine.
420Manipulated by the C<c> command to turn off tracing in all subs above the
421current one.
422
423=head4 C<@to_watch>
424
425The 'watch' expressions: to be evaluated before each line is executed.
426
427=head4 C<@typeahead>
428
429The typeahead buffer, used by C<DB::readline>.
430
431=head4 C<%alias>
432
433Command aliases. Stored as character strings to be substituted for a command
434entered.
435
436=head4 C<%break_on_load>
437
438Keys are file names, values are 1 (break when this file is loaded) or undef
439(don't break when it is loaded).
440
441=head4 C<%dbline>
442
be9a9b1d 443Keys are line numbers, values are C<condition\0action>. If used in numeric
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444context, values are 0 if not breakable, 1 if breakable, no matter what is
445in the actual hash entry.
446
447=head4 C<%had_breakpoints>
448
449Keys are file names; values are bitfields:
450
451=over 4
452
453=item * 1 - file has a breakpoint in it.
454
455=item * 2 - file has an action in it.
456
457=back
458
459A zero or undefined value means this file has neither.
460
461=head4 C<%option>
462
463Stores the debugger options. These are character string values.
464
465=head4 C<%postponed>
466
467Saves breakpoints for code that hasn't been compiled yet.
468Keys are subroutine names, values are:
469
470=over 4
471
be9a9b1d 472=item * C<compile> - break when this sub is compiled
69893cff 473
be9a9b1d 474=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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475
476=back
477
478=head4 C<%postponed_file>
479
480This hash keeps track of breakpoints that need to be set for files that have
481not yet been compiled. Keys are filenames; values are references to hashes.
482Each of these hashes is keyed by line number, and its values are breakpoint
be9a9b1d 483definitions (C<condition\0action>).
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484
485=head1 DEBUGGER INITIALIZATION
486
487The debugger's initialization actually jumps all over the place inside this
488package. This is because there are several BEGIN blocks (which of course
489execute immediately) spread through the code. Why is that?
490
491The debugger needs to be able to change some things and set some things up
492before the debugger code is compiled; most notably, the C<$deep> variable that
493C<DB::sub> uses to tell when a program has recursed deeply. In addition, the
494debugger has to turn off warnings while the debugger code is compiled, but then
495restore them to their original setting before the program being debugged begins
496executing.
497
498The first C<BEGIN> block simply turns off warnings by saving the current
499setting of C<$^W> and then setting it to zero. The second one initializes
500the debugger variables that are needed before the debugger begins executing.
501The third one puts C<$^X> back to its former value.
502
503We'll detail the second C<BEGIN> block later; just remember that if you need
504to initialize something before the debugger starts really executing, that's
505where it has to go.
506
507=cut
508
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509package DB;
510
c7e68384 511BEGIN {eval 'use IO::Handle'}; # Needed for flush only? breaks under miniperl
9eba6a4e 512
54d04a52 513# Debugger for Perl 5.00x; perl5db.pl patch level:
5561b870 514$VERSION = 1.30;
69893cff 515
e22ea7cc 516$header = "perl5db.pl version $VERSION";
d338d6fe 517
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518=head1 DEBUGGER ROUTINES
519
520=head2 C<DB::eval()>
521
522This function replaces straight C<eval()> inside the debugger; it simplifies
523the process of evaluating code in the user's context.
524
525The code to be evaluated is passed via the package global variable
526C<$DB::evalarg>; this is done to avoid fiddling with the contents of C<@_>.
527
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528Before we do the C<eval()>, we preserve the current settings of C<$trace>,
529C<$single>, C<$^D> and C<$usercontext>. The latter contains the
530preserved values of C<$@>, C<$!>, C<$^E>, C<$,>, C<$/>, C<$\>, C<$^W> and the
531user's current package, grabbed when C<DB::DB> got control. This causes the
532proper context to be used when the eval is actually done. Afterward, we
533restore C<$trace>, C<$single>, and C<$^D>.
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534
535Next we need to handle C<$@> without getting confused. We save C<$@> in a
536local lexical, localize C<$saved[0]> (which is where C<save()> will put
537C<$@>), and then call C<save()> to capture C<$@>, C<$!>, C<$^E>, C<$,>,
538C<$/>, C<$\>, and C<$^W>) and set C<$,>, C<$/>, C<$\>, and C<$^W> to values
539considered sane by the debugger. If there was an C<eval()> error, we print
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540it on the debugger's output. If C<$onetimedump> is defined, we call
541C<dumpit> if it's set to 'dump', or C<methods> if it's set to
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542'methods'. Setting it to something else causes the debugger to do the eval
543but not print the result - handy if you want to do something else with it
544(the "watch expressions" code does this to get the value of the watch
545expression but not show it unless it matters).
546
547In any case, we then return the list of output from C<eval> to the caller,
548and unwinding restores the former version of C<$@> in C<@saved> as well
549(the localization of C<$saved[0]> goes away at the end of this scope).
550
551=head3 Parameters and variables influencing execution of DB::eval()
552
553C<DB::eval> isn't parameterized in the standard way; this is to keep the
554debugger's calls to C<DB::eval()> from mucking with C<@_>, among other things.
555The variables listed below influence C<DB::eval()>'s execution directly.
556
557=over 4
558
559=item C<$evalarg> - the thing to actually be eval'ed
560
be9a9b1d 561=item C<$trace> - Current state of execution tracing
69893cff 562
be9a9b1d 563=item C<$single> - Current state of single-stepping
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564
565=item C<$onetimeDump> - what is to be displayed after the evaluation
566
567=item C<$onetimeDumpDepth> - how deep C<dumpit()> should go when dumping results
568
569=back
570
571The following variables are altered by C<DB::eval()> during its execution. They
572are "stacked" via C<local()>, enabling recursive calls to C<DB::eval()>.
573
574=over 4
575
576=item C<@res> - used to capture output from actual C<eval>.
577
578=item C<$otrace> - saved value of C<$trace>.
579
580=item C<$osingle> - saved value of C<$single>.
581
582=item C<$od> - saved value of C<$^D>.
583
584=item C<$saved[0]> - saved value of C<$@>.
585
586=item $\ - for output of C<$@> if there is an evaluation error.
587
588=back
589
590=head3 The problem of lexicals
591
592The context of C<DB::eval()> presents us with some problems. Obviously,
593we want to be 'sandboxed' away from the debugger's internals when we do
594the eval, but we need some way to control how punctuation variables and
595debugger globals are used.
596
597We can't use local, because the code inside C<DB::eval> can see localized
598variables; and we can't use C<my> either for the same reason. The code
599in this routine compromises and uses C<my>.
600
601After this routine is over, we don't have user code executing in the debugger's
602context, so we can use C<my> freely.
603
604=cut
605
606############################################## Begin lexical danger zone
607
608# 'my' variables used here could leak into (that is, be visible in)
609# the context that the code being evaluated is executing in. This means that
610# the code could modify the debugger's variables.
611#
612# Fiddling with the debugger's context could be Bad. We insulate things as
613# much as we can.
614
c1051fcf 615sub eval {
69893cff 616
c1051fcf 617 # 'my' would make it visible from user code
e22ea7cc 618 # but so does local! --tchrist
69893cff 619 # Remember: this localizes @DB::res, not @main::res.
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620 local @res;
621 {
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622
623 # Try to keep the user code from messing with us. Save these so that
624 # even if the eval'ed code changes them, we can put them back again.
625 # Needed because the user could refer directly to the debugger's
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626 # package globals (and any 'my' variables in this containing scope)
627 # inside the eval(), and we want to try to stay safe.
e22ea7cc 628 local $otrace = $trace;
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629 local $osingle = $single;
630 local $od = $^D;
631
632 # Untaint the incoming eval() argument.
633 { ($evalarg) = $evalarg =~ /(.*)/s; }
634
e22ea7cc 635 # $usercontext built in DB::DB near the comment
69893cff
RGS
636 # "set up the context for DB::eval ..."
637 # Evaluate and save any results.
e22ea7cc 638 @res = eval "$usercontext $evalarg;\n"; # '\n' for nice recursive debug
69893cff
RGS
639
640 # Restore those old values.
641 $trace = $otrace;
642 $single = $osingle;
643 $^D = $od;
c1051fcf 644 }
69893cff
RGS
645
646 # Save the current value of $@, and preserve it in the debugger's copy
647 # of the saved precious globals.
c1051fcf 648 my $at = $@;
69893cff
RGS
649
650 # Since we're only saving $@, we only have to localize the array element
651 # that it will be stored in.
e22ea7cc 652 local $saved[0]; # Preserve the old value of $@
c1051fcf 653 eval { &DB::save };
69893cff
RGS
654
655 # Now see whether we need to report an error back to the user.
c1051fcf 656 if ($at) {
69893cff
RGS
657 local $\ = '';
658 print $OUT $at;
659 }
660
661 # Display as required by the caller. $onetimeDump and $onetimedumpDepth
662 # are package globals.
663 elsif ($onetimeDump) {
e22ea7cc
RF
664 if ( $onetimeDump eq 'dump' ) {
665 local $option{dumpDepth} = $onetimedumpDepth
666 if defined $onetimedumpDepth;
667 dumpit( $OUT, \@res );
668 }
669 elsif ( $onetimeDump eq 'methods' ) {
670 methods( $res[0] );
671 }
69893cff 672 } ## end elsif ($onetimeDump)
c1051fcf 673 @res;
69893cff
RGS
674} ## end sub eval
675
676############################################## End lexical danger zone
c1051fcf 677
e22ea7cc
RF
678# After this point it is safe to introduce lexicals.
679# The code being debugged will be executing in its own context, and
69893cff 680# can't see the inside of the debugger.
d338d6fe 681#
e22ea7cc 682# However, one should not overdo it: leave as much control from outside as
69893cff
RGS
683# possible. If you make something a lexical, it's not going to be addressable
684# from outside the debugger even if you know its name.
685
d338d6fe 686# This file is automatically included if you do perl -d.
687# It's probably not useful to include this yourself.
688#
e22ea7cc 689# Before venturing further into these twisty passages, it is
2f7e9187
MS
690# wise to read the perldebguts man page or risk the ire of dragons.
691#
69893cff
RGS
692# (It should be noted that perldebguts will tell you a lot about
693# the underlying mechanics of how the debugger interfaces into the
694# Perl interpreter, but not a lot about the debugger itself. The new
695# comments in this code try to address this problem.)
696
d338d6fe 697# Note that no subroutine call is possible until &DB::sub is defined
36477c24 698# (for subroutines defined outside of the package DB). In fact the same is
d338d6fe 699# true if $deep is not defined.
055fd3a9
GS
700
701# Enhanced by ilya@math.ohio-state.edu (Ilya Zakharevich)
055fd3a9
GS
702
703# modified Perl debugger, to be run from Emacs in perldb-mode
704# Ray Lischner (uunet!mntgfx!lisch) as of 5 Nov 1990
705# Johan Vromans -- upgrade to 4.0 pl 10
706# Ilya Zakharevich -- patches after 5.001 (and some before ;-)
707
69893cff
RGS
708# (We have made efforts to clarify the comments in the change log
709# in other places; some of them may seem somewhat obscure as they
710# were originally written, and explaining them away from the code
711# in question seems conterproductive.. -JM)
712
713########################################################################
714# Changes: 0.94
715# + A lot of things changed after 0.94. First of all, core now informs
716# debugger about entry into XSUBs, overloaded operators, tied operations,
717# BEGIN and END. Handy with `O f=2'.
718# + This can make debugger a little bit too verbose, please be patient
719# and report your problems promptly.
720# + Now the option frame has 3 values: 0,1,2. XXX Document!
721# + Note that if DESTROY returns a reference to the object (or object),
722# the deletion of data may be postponed until the next function call,
723# due to the need to examine the return value.
724#
725# Changes: 0.95
726# + `v' command shows versions.
727#
e22ea7cc 728# Changes: 0.96
69893cff
RGS
729# + `v' command shows version of readline.
730# primitive completion works (dynamic variables, subs for `b' and `l',
731# options). Can `p %var'
732# + Better help (`h <' now works). New commands <<, >>, {, {{.
733# {dump|print}_trace() coded (to be able to do it from <<cmd).
734# + `c sub' documented.
735# + At last enough magic combined to stop after the end of debuggee.
736# + !! should work now (thanks to Emacs bracket matching an extra
737# `]' in a regexp is caught).
738# + `L', `D' and `A' span files now (as documented).
739# + Breakpoints in `require'd code are possible (used in `R').
740# + Some additional words on internal work of debugger.
741# + `b load filename' implemented.
742# + `b postpone subr' implemented.
743# + now only `q' exits debugger (overwritable on $inhibit_exit).
744# + When restarting debugger breakpoints/actions persist.
e22ea7cc 745# + Buglet: When restarting debugger only one breakpoint/action per
69893cff
RGS
746# autoloaded function persists.
747#
36477c24 748# Changes: 0.97: NonStop will not stop in at_exit().
69893cff
RGS
749# + Option AutoTrace implemented.
750# + Trace printed differently if frames are printed too.
751# + new `inhibitExit' option.
752# + printing of a very long statement interruptible.
1d06cb2d 753# Changes: 0.98: New command `m' for printing possible methods
69893cff
RGS
754# + 'l -' is a synonym for `-'.
755# + Cosmetic bugs in printing stack trace.
756# + `frame' & 8 to print "expanded args" in stack trace.
757# + Can list/break in imported subs.
758# + new `maxTraceLen' option.
759# + frame & 4 and frame & 8 granted.
760# + new command `m'
761# + nonstoppable lines do not have `:' near the line number.
762# + `b compile subname' implemented.
763# + Will not use $` any more.
764# + `-' behaves sane now.
477ea2b1 765# Changes: 0.99: Completion for `f', `m'.
69893cff
RGS
766# + `m' will remove duplicate names instead of duplicate functions.
767# + `b load' strips trailing whitespace.
768# completion ignores leading `|'; takes into account current package
769# when completing a subroutine name (same for `l').
055fd3a9
GS
770# Changes: 1.07: Many fixed by tchrist 13-March-2000
771# BUG FIXES:
04e43a21 772# + Added bare minimal security checks on perldb rc files, plus
055fd3a9
GS
773# comments on what else is needed.
774# + Fixed the ornaments that made "|h" completely unusable.
775# They are not used in print_help if they will hurt. Strip pod
776# if we're paging to less.
777# + Fixed mis-formatting of help messages caused by ornaments
e22ea7cc
RF
778# to restore Larry's original formatting.
779# + Fixed many other formatting errors. The code is still suboptimal,
04e43a21 780# and needs a lot of work at restructuring. It's also misindented
055fd3a9
GS
781# in many places.
782# + Fixed bug where trying to look at an option like your pager
e22ea7cc 783# shows "1".
055fd3a9
GS
784# + Fixed some $? processing. Note: if you use csh or tcsh, you will
785# lose. You should consider shell escapes not using their shell,
786# or else not caring about detailed status. This should really be
787# unified into one place, too.
788# + Fixed bug where invisible trailing whitespace on commands hoses you,
04e43a21 789# tricking Perl into thinking you weren't calling a debugger command!
055fd3a9
GS
790# + Fixed bug where leading whitespace on commands hoses you. (One
791# suggests a leading semicolon or any other irrelevant non-whitespace
792# to indicate literal Perl code.)
793# + Fixed bugs that ate warnings due to wrong selected handle.
794# + Fixed a precedence bug on signal stuff.
795# + Fixed some unseemly wording.
796# + Fixed bug in help command trying to call perl method code.
797# + Fixed to call dumpvar from exception handler. SIGPIPE killed us.
798# ENHANCEMENTS:
799# + Added some comments. This code is still nasty spaghetti.
800# + Added message if you clear your pre/post command stacks which was
801# very easy to do if you just typed a bare >, <, or {. (A command
802# without an argument should *never* be a destructive action; this
803# API is fundamentally screwed up; likewise option setting, which
804# is equally buggered.)
805# + Added command stack dump on argument of "?" for >, <, or {.
806# + Added a semi-built-in doc viewer command that calls man with the
807# proper %Config::Config path (and thus gets caching, man -k, etc),
808# or else perldoc on obstreperous platforms.
809# + Added to and rearranged the help information.
810# + Detected apparent misuse of { ... } to declare a block; this used
811# to work but now is a command, and mysteriously gave no complaint.
04e43a21
DL
812#
813# Changes: 1.08: Apr 25, 2001 Jon Eveland <jweveland@yahoo.com>
814# BUG FIX:
815# + This patch to perl5db.pl cleans up formatting issues on the help
816# summary (h h) screen in the debugger. Mostly columnar alignment
817# issues, plus converted the printed text to use all spaces, since
818# tabs don't seem to help much here.
819#
820# Changes: 1.09: May 19, 2001 Ilya Zakharevich <ilya@math.ohio-state.edu>
69893cff
RGS
821# Minor bugs corrected;
822# + Support for auto-creation of new TTY window on startup, either
823# unconditionally, or if started as a kid of another debugger session;
824# + New `O'ption CreateTTY
825# I<CreateTTY> bits control attempts to create a new TTY on events:
e22ea7cc 826# 1: on fork()
69893cff
RGS
827# 2: debugger is started inside debugger
828# 4: on startup
829# + Code to auto-create a new TTY window on OS/2 (currently one
830# extra window per session - need named pipes to have more...);
831# + Simplified interface for custom createTTY functions (with a backward
832# compatibility hack); now returns the TTY name to use; return of ''
833# means that the function reset the I/O handles itself;
834# + Better message on the semantic of custom createTTY function;
835# + Convert the existing code to create a TTY into a custom createTTY
836# function;
837# + Consistent support for TTY names of the form "TTYin,TTYout";
838# + Switch line-tracing output too to the created TTY window;
839# + make `b fork' DWIM with CORE::GLOBAL::fork;
840# + High-level debugger API cmd_*():
04e43a21
DL
841# cmd_b_load($filenamepart) # b load filenamepart
842# cmd_b_line($lineno [, $cond]) # b lineno [cond]
843# cmd_b_sub($sub [, $cond]) # b sub [cond]
844# cmd_stop() # Control-C
492652be 845# cmd_d($lineno) # d lineno (B)
04e43a21
DL
846# The cmd_*() API returns FALSE on failure; in this case it outputs
847# the error message to the debugging output.
69893cff 848# + Low-level debugger API
04e43a21
DL
849# break_on_load($filename) # b load filename
850# @files = report_break_on_load() # List files with load-breakpoints
851# breakable_line_in_filename($name, $from [, $to])
852# # First breakable line in the
853# # range $from .. $to. $to defaults
e22ea7cc 854# # to $from, and may be less than
69893cff 855# # $to
04e43a21
DL
856# breakable_line($from [, $to]) # Same for the current file
857# break_on_filename_line($name, $lineno [, $cond])
e22ea7cc 858# # Set breakpoint,$cond defaults to
69893cff 859# # 1
04e43a21
DL
860# break_on_filename_line_range($name, $from, $to [, $cond])
861# # As above, on the first
862# # breakable line in range
863# break_on_line($lineno [, $cond]) # As above, in the current file
864# break_subroutine($sub [, $cond]) # break on the first breakable line
865# ($name, $from, $to) = subroutine_filename_lines($sub)
866# # The range of lines of the text
867# The low-level API returns TRUE on success, and die()s on failure.
868#
869# Changes: 1.10: May 23, 2001 Daniel Lewart <d-lewart@uiuc.edu>
870# BUG FIXES:
871# + Fixed warnings generated by "perl -dWe 42"
872# + Corrected spelling errors
873# + Squeezed Help (h) output into 80 columns
600d99fa
DL
874#
875# Changes: 1.11: May 24, 2001 David Dyck <dcd@tc.fluke.com>
876# + Made "x @INC" work like it used to
877#
878# Changes: 1.12: May 24, 2001 Daniel Lewart <d-lewart@uiuc.edu>
879# + Fixed warnings generated by "O" (Show debugger options)
880# + Fixed warnings generated by "p 42" (Print expression)
6f891d7d 881# Changes: 1.13: Jun 19, 2001 Scott.L.Miller@compaq.com
e22ea7cc 882# + Added windowSize option
2f7e9187
MS
883# Changes: 1.14: Oct 9, 2001 multiple
884# + Clean up after itself on VMS (Charles Lane in 12385)
885# + Adding "@ file" syntax (Peter Scott in 12014)
886# + Debug reloading selfloaded stuff (Ilya Zakharevich in 11457)
887# + $^S and other debugger fixes (Ilya Zakharevich in 11120)
888# + Forgot a my() declaration (Ilya Zakharevich in 11085)
889# Changes: 1.15: Nov 6, 2001 Michael G Schwern <schwern@pobox.com>
890# + Updated 1.14 change log
891# + Added *dbline explainatory comments
892# + Mentioning perldebguts man page
492652be 893# Changes: 1.16: Feb 15, 2002 Mark-Jason Dominus <mjd@plover.com>
69893cff 894# + $onetimeDump improvements
492652be
RF
895# Changes: 1.17: Feb 20, 2002 Richard Foley <richard.foley@rfi.net>
896# Moved some code to cmd_[.]()'s for clarity and ease of handling,
e22ea7cc
RF
897# rationalised the following commands and added cmd_wrapper() to
898# enable switching between old and frighteningly consistent new
492652be
RF
899# behaviours for diehards: 'o CommandSet=pre580' (sigh...)
900# a(add), A(del) # action expr (added del by line)
901# + b(add), B(del) # break [line] (was b,D)
e22ea7cc 902# + w(add), W(del) # watch expr (was W,W)
69893cff 903# # added del by expr
492652be
RF
904# + h(summary), h h(long) # help (hh) (was h h,h)
905# + m(methods), M(modules) # ... (was m,v)
906# + o(option) # lc (was O)
907# + v(view code), V(view Variables) # ... (was w,V)
aef14ef9
RF
908# Changes: 1.18: Mar 17, 2002 Richard Foley <richard.foley@rfi.net>
909# + fixed missing cmd_O bug
471505cc
SB
910# Changes: 1.19: Mar 29, 2002 Spider Boardman
911# + Added missing local()s -- DB::DB is called recursively.
35408c4e
RF
912# Changes: 1.20: Feb 17, 2003 Richard Foley <richard.foley@rfi.net>
913# + pre'n'post commands no longer trashed with no args
914# + watch val joined out of eval()
69893cff
RGS
915# Changes: 1.21: Jun 04, 2003 Joe McMahon <mcmahon@ibiblio.org>
916# + Added comments and reformatted source. No bug fixes/enhancements.
917# + Includes cleanup by Robin Barker and Jarkko Hietaniemi.
918# Changes: 1.22 Jun 09, 2003 Alex Vandiver <alexmv@MIT.EDU>
919# + Flush stdout/stderr before the debugger prompt is printed.
920# Changes: 1.23: Dec 21, 2003 Dominique Quatravaux
de5e1a3d 921# + Fix a side-effect of bug #24674 in the perl debugger ("odd taint bug")
e219e2fb
RF
922# Changes: 1.24: Mar 03, 2004 Richard Foley <richard.foley@rfi.net>
923# + Added command to save all debugger commands for sourcing later.
3c4b39be 924# + Added command to display parent inheritance tree of given class.
e219e2fb 925# + Fixed minor newline in history bug.
e22ea7cc
RF
926# Changes: 1.25: Apr 17, 2004 Richard Foley <richard.foley@rfi.net>
927# + Fixed option bug (setting invalid options + not recognising valid short forms)
928# Changes: 1.26: Apr 22, 2004 Richard Foley <richard.foley@rfi.net>
929# + unfork the 5.8.x and 5.9.x debuggers.
930# + whitespace and assertions call cleanup across versions
931# + H * deletes (resets) history
932# + i now handles Class + blessed objects
7fddc82f
RF
933# Changes: 1.27: May 09, 2004 Richard Foley <richard.foley@rfi.net>
934# + updated pod page references - clunky.
935# + removed windowid restriction for forking into an xterm.
936# + more whitespace again.
937# + wrapped restart and enabled rerun [-n] (go back n steps) command.
2cbb2ee1
RGS
938# Changes: 1.28: Oct 12, 2004 Richard Foley <richard.foley@rfi.net>
939# + Added threads support (inc. e and E commands)
6fae1ad7
RF
940# Changes: 1.29: Nov 28, 2006 Bo Lindbergh <blgl@hagernas.com>
941# + Added macosx_get_fork_TTY support
5561b870
A
942# Changes: 1.30: Mar 06, 2007 Andreas Koenig <andk@cpan.org>
943# + Added HistFile, HistSize
6fae1ad7 944########################################################################
d338d6fe 945
69893cff
RGS
946=head1 DEBUGGER INITIALIZATION
947
948The debugger starts up in phases.
949
950=head2 BASIC SETUP
951
952First, it initializes the environment it wants to run in: turning off
953warnings during its own compilation, defining variables which it will need
954to avoid warnings later, setting itself up to not exit when the program
955terminates, and defaulting to printing return values for the C<r> command.
956
957=cut
958
eda6e075 959# Needed for the statement after exec():
69893cff
RGS
960#
961# This BEGIN block is simply used to switch off warnings during debugger
962# compiliation. Probably it would be better practice to fix the warnings,
963# but this is how it's done at the moment.
eda6e075 964
e22ea7cc
RF
965BEGIN {
966 $ini_warn = $^W;
967 $^W = 0;
968} # Switch compilation warnings off until another BEGIN.
d12a4851 969
69893cff
RGS
970local ($^W) = 0; # Switch run-time warnings off during init.
971
2cbb2ee1
RGS
972=head2 THREADS SUPPORT
973
974If we are running under a threaded Perl, we require threads and threads::shared
975if the environment variable C<PERL5DB_THREADED> is set, to enable proper
976threaded debugger control. C<-dt> can also be used to set this.
977
978Each new thread will be announced and the debugger prompt will always inform
979you of each new thread created. It will also indicate the thread id in which
980we are currently running within the prompt like this:
981
982 [tid] DB<$i>
983
984Where C<[tid]> is an integer thread id and C<$i> is the familiar debugger
985command prompt. The prompt will show: C<[0]> when running under threads, but
986not actually in a thread. C<[tid]> is consistent with C<gdb> usage.
987
988While running under threads, when you set or delete a breakpoint (etc.), this
989will apply to all threads, not just the currently running one. When you are
990in a currently executing thread, you will stay there until it completes. With
991the current implementation it is not currently possible to hop from one thread
992to another.
993
994The C<e> and C<E> commands are currently fairly minimal - see C<h e> and C<h E>.
995
996Note that threading support was built into the debugger as of Perl version
997C<5.8.6> and debugger version C<1.2.8>.
998
999=cut
1000
1001BEGIN {
1002 # ensure we can share our non-threaded variables or no-op
1003 if ($ENV{PERL5DB_THREADED}) {
1004 require threads;
1005 require threads::shared;
1006 import threads::shared qw(share);
1007 $DBGR;
1008 share(\$DBGR);
1009 lock($DBGR);
1010 print "Threads support enabled\n";
1011 } else {
1012 *lock = sub(*) {};
1013 *share = sub(*) {};
1014 }
1015}
1016
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RGS
1017# This would probably be better done with "use vars", but that wasn't around
1018# when this code was originally written. (Neither was "use strict".) And on
1019# the principle of not fiddling with something that was working, this was
1020# left alone.
1021warn( # Do not ;-)
2cbb2ee1 1022 # These variables control the execution of 'dumpvar.pl'.
69893cff
RGS
1023 $dumpvar::hashDepth,
1024 $dumpvar::arrayDepth,
1025 $dumpvar::dumpDBFiles,
1026 $dumpvar::dumpPackages,
1027 $dumpvar::quoteHighBit,
1028 $dumpvar::printUndef,
1029 $dumpvar::globPrint,
1030 $dumpvar::usageOnly,
1031
1032 # used to save @ARGV and extract any debugger-related flags.
1033 @ARGS,
1034
1035 # used to control die() reporting in diesignal()
1036 $Carp::CarpLevel,
1037
1038 # used to prevent multiple entries to diesignal()
1039 # (if for instance diesignal() itself dies)
1040 $panic,
1041
1042 # used to prevent the debugger from running nonstop
1043 # after a restart
1044 $second_time,
1045 )
1046 if 0;
d338d6fe 1047
2cbb2ee1
RGS
1048foreach my $k (keys (%INC)) {
1049 &share(\$main::{'_<'.$filename});
1050};
1051
54d04a52 1052# Command-line + PERLLIB:
69893cff 1053# Save the contents of @INC before they are modified elsewhere.
54d04a52
IZ
1054@ini_INC = @INC;
1055
69893cff
RGS
1056# This was an attempt to clear out the previous values of various
1057# trapped errors. Apparently it didn't help. XXX More info needed!
d338d6fe 1058# $prevwarn = $prevdie = $prevbus = $prevsegv = ''; # Does not help?!
1059
69893cff
RGS
1060# We set these variables to safe values. We don't want to blindly turn
1061# off warnings, because other packages may still want them.
e22ea7cc
RF
1062$trace = $signal = $single = 0; # Uninitialized warning suppression
1063 # (local $^W cannot help - other packages!).
69893cff
RGS
1064
1065# Default to not exiting when program finishes; print the return
1066# value when the 'r' command is used to return from a subroutine.
55497cff 1067$inhibit_exit = $option{PrintRet} = 1;
d338d6fe 1068
69893cff
RGS
1069=head1 OPTION PROCESSING
1070
1071The debugger's options are actually spread out over the debugger itself and
1072C<dumpvar.pl>; some of these are variables to be set, while others are
1073subs to be called with a value. To try to make this a little easier to
1074manage, the debugger uses a few data structures to define what options
1075are legal and how they are to be processed.
1076
1077First, the C<@options> array defines the I<names> of all the options that
1078are to be accepted.
1079
1080=cut
1081
1082@options = qw(
5561b870 1083 CommandSet HistFile HistSize
e22ea7cc
RF
1084 hashDepth arrayDepth dumpDepth
1085 DumpDBFiles DumpPackages DumpReused
1086 compactDump veryCompact quote
1087 HighBit undefPrint globPrint
1088 PrintRet UsageOnly frame
1089 AutoTrace TTY noTTY
1090 ReadLine NonStop LineInfo
1091 maxTraceLen recallCommand ShellBang
1092 pager tkRunning ornaments
1093 signalLevel warnLevel dieLevel
1094 inhibit_exit ImmediateStop bareStringify
1095 CreateTTY RemotePort windowSize
584420f0 1096 DollarCaretP
e22ea7cc 1097);
d12a4851 1098
584420f0 1099@RememberOnROptions = qw(DollarCaretP);
d12a4851 1100
69893cff
RGS
1101=pod
1102
1103Second, C<optionVars> lists the variables that each option uses to save its
1104state.
1105
1106=cut
1107
1108%optionVars = (
e22ea7cc
RF
1109 hashDepth => \$dumpvar::hashDepth,
1110 arrayDepth => \$dumpvar::arrayDepth,
1111 CommandSet => \$CommandSet,
1112 DumpDBFiles => \$dumpvar::dumpDBFiles,
1113 DumpPackages => \$dumpvar::dumpPackages,
1114 DumpReused => \$dumpvar::dumpReused,
1115 HighBit => \$dumpvar::quoteHighBit,
1116 undefPrint => \$dumpvar::printUndef,
1117 globPrint => \$dumpvar::globPrint,
1118 UsageOnly => \$dumpvar::usageOnly,
1119 CreateTTY => \$CreateTTY,
1120 bareStringify => \$dumpvar::bareStringify,
1121 frame => \$frame,
1122 AutoTrace => \$trace,
1123 inhibit_exit => \$inhibit_exit,
1124 maxTraceLen => \$maxtrace,
1125 ImmediateStop => \$ImmediateStop,
1126 RemotePort => \$remoteport,
1127 windowSize => \$window,
5561b870
A
1128 HistFile => \$histfile,
1129 HistSize => \$histsize,
69893cff
RGS
1130);
1131
1132=pod
1133
1134Third, C<%optionAction> defines the subroutine to be called to process each
1135option.
1136
1137=cut
1138
1139%optionAction = (
1140 compactDump => \&dumpvar::compactDump,
1141 veryCompact => \&dumpvar::veryCompact,
1142 quote => \&dumpvar::quote,
1143 TTY => \&TTY,
1144 noTTY => \&noTTY,
1145 ReadLine => \&ReadLine,
1146 NonStop => \&NonStop,
1147 LineInfo => \&LineInfo,
1148 recallCommand => \&recallCommand,
1149 ShellBang => \&shellBang,
1150 pager => \&pager,
1151 signalLevel => \&signalLevel,
1152 warnLevel => \&warnLevel,
1153 dieLevel => \&dieLevel,
1154 tkRunning => \&tkRunning,
1155 ornaments => \&ornaments,
1156 RemotePort => \&RemotePort,
1157 DollarCaretP => \&DollarCaretP,
d12a4851
JH
1158);
1159
69893cff
RGS
1160=pod
1161
1162Last, the C<%optionRequire> notes modules that must be C<require>d if an
1163option is used.
1164
1165=cut
d338d6fe 1166
69893cff
RGS
1167# Note that this list is not complete: several options not listed here
1168# actually require that dumpvar.pl be loaded for them to work, but are
1169# not in the table. A subsequent patch will correct this problem; for
1170# the moment, we're just recommenting, and we are NOT going to change
1171# function.
eda6e075 1172%optionRequire = (
69893cff
RGS
1173 compactDump => 'dumpvar.pl',
1174 veryCompact => 'dumpvar.pl',
1175 quote => 'dumpvar.pl',
e22ea7cc 1176);
69893cff
RGS
1177
1178=pod
1179
1180There are a number of initialization-related variables which can be set
1181by putting code to set them in a BEGIN block in the C<PERL5DB> environment
1182variable. These are:
1183
1184=over 4
1185
1186=item C<$rl> - readline control XXX needs more explanation
1187
1188=item C<$warnLevel> - whether or not debugger takes over warning handling
1189
1190=item C<$dieLevel> - whether or not debugger takes over die handling
1191
1192=item C<$signalLevel> - whether or not debugger takes over signal handling
1193
1194=item C<$pre> - preprompt actions (array reference)
1195
1196=item C<$post> - postprompt actions (array reference)
1197
1198=item C<$pretype>
1199
1200=item C<$CreateTTY> - whether or not to create a new TTY for this debugger
1201
1202=item C<$CommandSet> - which command set to use (defaults to new, documented set)
1203
1204=back
1205
1206=cut
d338d6fe 1207
1208# These guys may be defined in $ENV{PERL5DB} :
69893cff
RGS
1209$rl = 1 unless defined $rl;
1210$warnLevel = 1 unless defined $warnLevel;
1211$dieLevel = 1 unless defined $dieLevel;
1212$signalLevel = 1 unless defined $signalLevel;
1213$pre = [] unless defined $pre;
1214$post = [] unless defined $post;
1215$pretype = [] unless defined $pretype;
1216$CreateTTY = 3 unless defined $CreateTTY;
1217$CommandSet = '580' unless defined $CommandSet;
1218
2cbb2ee1
RGS
1219share($rl);
1220share($warnLevel);
1221share($dieLevel);
1222share($signalLevel);
1223share($pre);
1224share($post);
1225share($pretype);
1226share($rl);
1227share($CreateTTY);
1228share($CommandSet);
1229
69893cff
RGS
1230=pod
1231
1232The default C<die>, C<warn>, and C<signal> handlers are set up.
1233
1234=cut
055fd3a9 1235
d338d6fe 1236warnLevel($warnLevel);
1237dieLevel($dieLevel);
1238signalLevel($signalLevel);
055fd3a9 1239
69893cff
RGS
1240=pod
1241
1242The pager to be used is needed next. We try to get it from the
5561b870 1243environment first. If it's not defined there, we try to find it in
69893cff
RGS
1244the Perl C<Config.pm>. If it's not there, we default to C<more>. We
1245then call the C<pager()> function to save the pager name.
1246
1247=cut
1248
1249# This routine makes sure $pager is set up so that '|' can use it.
4865a36d 1250pager(
e22ea7cc 1251
69893cff 1252 # If PAGER is defined in the environment, use it.
e22ea7cc
RF
1253 defined $ENV{PAGER}
1254 ? $ENV{PAGER}
69893cff
RGS
1255
1256 # If not, see if Config.pm defines it.
e22ea7cc
RF
1257 : eval { require Config }
1258 && defined $Config::Config{pager}
1259 ? $Config::Config{pager}
69893cff
RGS
1260
1261 # If not, fall back to 'more'.
e22ea7cc
RF
1262 : 'more'
1263 )
1264 unless defined $pager;
69893cff
RGS
1265
1266=pod
1267
1268We set up the command to be used to access the man pages, the command
be9a9b1d
AT
1269recall character (C<!> unless otherwise defined) and the shell escape
1270character (C<!> unless otherwise defined). Yes, these do conflict, and
69893cff
RGS
1271neither works in the debugger at the moment.
1272
1273=cut
1274
055fd3a9 1275setman();
69893cff
RGS
1276
1277# Set up defaults for command recall and shell escape (note:
1278# these currently don't work in linemode debugging).
d338d6fe 1279&recallCommand("!") unless defined $prc;
69893cff
RGS
1280&shellBang("!") unless defined $psh;
1281
1282=pod
1283
1284We then set up the gigantic string containing the debugger help.
1285We also set the limit on the number of arguments we'll display during a
1286trace.
1287
1288=cut
1289
04e43a21 1290sethelp();
69893cff
RGS
1291
1292# If we didn't get a default for the length of eval/stack trace args,
1293# set it here.
1d06cb2d 1294$maxtrace = 400 unless defined $maxtrace;
69893cff
RGS
1295
1296=head2 SETTING UP THE DEBUGGER GREETING
1297
be9a9b1d 1298The debugger I<greeting> helps to inform the user how many debuggers are
69893cff
RGS
1299running, and whether the current debugger is the primary or a child.
1300
1301If we are the primary, we just hang onto our pid so we'll have it when
1302or if we start a child debugger. If we are a child, we'll set things up
1303so we'll have a unique greeting and so the parent will give us our own
1304TTY later.
1305
1306We save the current contents of the C<PERLDB_PIDS> environment variable
1307because we mess around with it. We'll also need to hang onto it because
1308we'll need it if we restart.
1309
1310Child debuggers make a label out of the current PID structure recorded in
1311PERLDB_PIDS plus the new PID. They also mark themselves as not having a TTY
1312yet so the parent will give them one later via C<resetterm()>.
1313
1314=cut
1315
e22ea7cc 1316# Save the current contents of the environment; we're about to
69893cff 1317# much with it. We'll need this if we have to restart.
f1583d8f 1318$ini_pids = $ENV{PERLDB_PIDS};
69893cff 1319
e22ea7cc
RF
1320if ( defined $ENV{PERLDB_PIDS} ) {
1321
69893cff 1322 # We're a child. Make us a label out of the current PID structure
e22ea7cc 1323 # recorded in PERLDB_PIDS plus our (new) PID. Mark us as not having
69893cff 1324 # a term yet so the parent will give us one later via resetterm().
55f4245e
JM
1325
1326 my $env_pids = $ENV{PERLDB_PIDS};
1327 $pids = "[$env_pids]";
1328
1329 # Unless we are on OpenVMS, all programs under the DCL shell run under
1330 # the same PID.
1331
1332 if (($^O eq 'VMS') && ($env_pids =~ /\b$$\b/)) {
1333 $term_pid = $$;
1334 }
1335 else {
1336 $ENV{PERLDB_PIDS} .= "->$$";
1337 $term_pid = -1;
1338 }
1339
69893cff
RGS
1340} ## end if (defined $ENV{PERLDB_PIDS...
1341else {
e22ea7cc
RF
1342
1343 # We're the parent PID. Initialize PERLDB_PID in case we end up with a
69893cff
RGS
1344 # child debugger, and mark us as the parent, so we'll know to set up
1345 # more TTY's is we have to.
1346 $ENV{PERLDB_PIDS} = "$$";
619a0444 1347 $pids = "[pid=$$]";
e22ea7cc 1348 $term_pid = $$;
f1583d8f 1349}
69893cff 1350
f1583d8f 1351$pidprompt = '';
69893cff
RGS
1352
1353# Sets up $emacs as a synonym for $slave_editor.
1354*emacs = $slave_editor if $slave_editor; # May be used in afterinit()...
1355
1356=head2 READING THE RC FILE
1357
1358The debugger will read a file of initialization options if supplied. If
1359running interactively, this is C<.perldb>; if not, it's C<perldb.ini>.
1360
1361=cut
1362
1363# As noted, this test really doesn't check accurately that the debugger
1364# is running at a terminal or not.
d338d6fe 1365
98274836
JM
1366my $dev_tty = '/dev/tty';
1367 $dev_tty = 'TT:' if ($^O eq 'VMS');
1368if ( -e $dev_tty ) { # this is the wrong metric!
e22ea7cc
RF
1369 $rcfile = ".perldb";
1370}
69893cff
RGS
1371else {
1372 $rcfile = "perldb.ini";
d338d6fe 1373}
1374
69893cff
RGS
1375=pod
1376
1377The debugger does a safety test of the file to be read. It must be owned
1378either by the current user or root, and must only be writable by the owner.
1379
1380=cut
1381
1382# This wraps a safety test around "do" to read and evaluate the init file.
1383#
055fd3a9
GS
1384# This isn't really safe, because there's a race
1385# between checking and opening. The solution is to
1386# open and fstat the handle, but then you have to read and
1387# eval the contents. But then the silly thing gets
69893cff
RGS
1388# your lexical scope, which is unfortunate at best.
1389sub safe_do {
055fd3a9
GS
1390 my $file = shift;
1391
1392 # Just exactly what part of the word "CORE::" don't you understand?
69893cff
RGS
1393 local $SIG{__WARN__};
1394 local $SIG{__DIE__};
055fd3a9 1395
e22ea7cc 1396 unless ( is_safe_file($file) ) {
69893cff 1397 CORE::warn <<EO_GRIPE;
055fd3a9
GS
1398perldb: Must not source insecure rcfile $file.
1399 You or the superuser must be the owner, and it must not
69893cff 1400 be writable by anyone but its owner.
055fd3a9 1401EO_GRIPE
69893cff
RGS
1402 return;
1403 } ## end unless (is_safe_file($file...
055fd3a9
GS
1404
1405 do $file;
1406 CORE::warn("perldb: couldn't parse $file: $@") if $@;
69893cff 1407} ## end sub safe_do
055fd3a9 1408
69893cff
RGS
1409# This is the safety test itself.
1410#
055fd3a9
GS
1411# Verifies that owner is either real user or superuser and that no
1412# one but owner may write to it. This function is of limited use
1413# when called on a path instead of upon a handle, because there are
1414# no guarantees that filename (by dirent) whose file (by ino) is
e22ea7cc 1415# eventually accessed is the same as the one tested.
055fd3a9
GS
1416# Assumes that the file's existence is not in doubt.
1417sub is_safe_file {
1418 my $path = shift;
69893cff 1419 stat($path) || return; # mysteriously vaporized
e22ea7cc 1420 my ( $dev, $ino, $mode, $nlink, $uid, $gid ) = stat(_);
055fd3a9
GS
1421
1422 return 0 if $uid != 0 && $uid != $<;
1423 return 0 if $mode & 022;
1424 return 1;
69893cff 1425} ## end sub is_safe_file
055fd3a9 1426
69893cff 1427# If the rcfile (whichever one we decided was the right one to read)
e22ea7cc
RF
1428# exists, we safely do it.
1429if ( -f $rcfile ) {
055fd3a9 1430 safe_do("./$rcfile");
69893cff 1431}
e22ea7cc 1432
69893cff 1433# If there isn't one here, try the user's home directory.
e22ea7cc 1434elsif ( defined $ENV{HOME} && -f "$ENV{HOME}/$rcfile" ) {
055fd3a9
GS
1435 safe_do("$ENV{HOME}/$rcfile");
1436}
e22ea7cc 1437
69893cff 1438# Else try the login directory.
e22ea7cc 1439elsif ( defined $ENV{LOGDIR} && -f "$ENV{LOGDIR}/$rcfile" ) {
055fd3a9 1440 safe_do("$ENV{LOGDIR}/$rcfile");
d338d6fe 1441}
1442
69893cff 1443# If the PERLDB_OPTS variable has options in it, parse those out next.
e22ea7cc
RF
1444if ( defined $ENV{PERLDB_OPTS} ) {
1445 parse_options( $ENV{PERLDB_OPTS} );
d338d6fe 1446}
1447
69893cff
RGS
1448=pod
1449
1450The last thing we do during initialization is determine which subroutine is
1451to be used to obtain a new terminal when a new debugger is started. Right now,
6fae1ad7 1452the debugger only handles X Windows, OS/2, and Mac OS X (darwin).
69893cff
RGS
1453
1454=cut
1455
1456# Set up the get_fork_TTY subroutine to be aliased to the proper routine.
1457# Works if you're running an xterm or xterm-like window, or you're on
6fae1ad7
RF
1458# OS/2, or on Mac OS X. This may need some expansion.
1459
1460if (not defined &get_fork_TTY) # only if no routine exists
69893cff 1461{
6fae1ad7
RF
1462 if (defined $ENV{TERM} # If we know what kind
1463 # of terminal this is,
1464 and $ENV{TERM} eq 'xterm' # and it's an xterm,
1465 and defined $ENV{DISPLAY} # and what display it's on,
1466 )
1467 {
1468 *get_fork_TTY = \&xterm_get_fork_TTY; # use the xterm version
1469 }
1470 elsif ( $^O eq 'os2' ) { # If this is OS/2,
1471 *get_fork_TTY = \&os2_get_fork_TTY; # use the OS/2 version
1472 }
1473 elsif ( $^O eq 'darwin' # If this is Mac OS X
1474 and defined $ENV{TERM_PROGRAM} # and we're running inside
1475 and $ENV{TERM_PROGRAM}
1476 eq 'Apple_Terminal' # Terminal.app
1477 )
1478 {
1479 *get_fork_TTY = \&macosx_get_fork_TTY; # use the Mac OS X version
1480 }
69893cff 1481} ## end if (not defined &get_fork_TTY...
e22ea7cc 1482
dbb46cec
DQ
1483# untaint $^O, which may have been tainted by the last statement.
1484# see bug [perl #24674]
e22ea7cc
RF
1485$^O =~ m/^(.*)\z/;
1486$^O = $1;
f1583d8f 1487
d12a4851 1488# Here begin the unreadable code. It needs fixing.
055fd3a9 1489
69893cff
RGS
1490=head2 RESTART PROCESSING
1491
1492This section handles the restart command. When the C<R> command is invoked, it
1493tries to capture all of the state it can into environment variables, and
1494then sets C<PERLDB_RESTART>. When we start executing again, we check to see
1495if C<PERLDB_RESTART> is there; if so, we reload all the information that
1496the R command stuffed into the environment variables.
1497
1498 PERLDB_RESTART - flag only, contains no restart data itself.
1499 PERLDB_HIST - command history, if it's available
1500 PERLDB_ON_LOAD - breakpoints set by the rc file
1501 PERLDB_POSTPONE - subs that have been loaded/not executed, and have actions
1502 PERLDB_VISITED - files that had breakpoints
1503 PERLDB_FILE_... - breakpoints for a file
1504 PERLDB_OPT - active options
1505 PERLDB_INC - the original @INC
1506 PERLDB_PRETYPE - preprompt debugger actions
1507 PERLDB_PRE - preprompt Perl code
1508 PERLDB_POST - post-prompt Perl code
1509 PERLDB_TYPEAHEAD - typeahead captured by readline()
1510
1511We chug through all these variables and plug the values saved in them
1512back into the appropriate spots in the debugger.
1513
1514=cut
1515
e22ea7cc
RF
1516if ( exists $ENV{PERLDB_RESTART} ) {
1517
69893cff 1518 # We're restarting, so we don't need the flag that says to restart anymore.
e22ea7cc
RF
1519 delete $ENV{PERLDB_RESTART};
1520
1521 # $restart = 1;
1522 @hist = get_list('PERLDB_HIST');
1523 %break_on_load = get_list("PERLDB_ON_LOAD");
1524 %postponed = get_list("PERLDB_POSTPONE");
69893cff 1525
2cbb2ee1
RGS
1526 share(@hist);
1527 share(@truehist);
1528 share(%break_on_load);
1529 share(%postponed);
1530
69893cff 1531 # restore breakpoints/actions
e22ea7cc
RF
1532 my @had_breakpoints = get_list("PERLDB_VISITED");
1533 for ( 0 .. $#had_breakpoints ) {
1534 my %pf = get_list("PERLDB_FILE_$_");
1535 $postponed_file{ $had_breakpoints[$_] } = \%pf if %pf;
1536 }
69893cff
RGS
1537
1538 # restore options
e22ea7cc
RF
1539 my %opt = get_list("PERLDB_OPT");
1540 my ( $opt, $val );
1541 while ( ( $opt, $val ) = each %opt ) {
1542 $val =~ s/[\\\']/\\$1/g;
1543 parse_options("$opt'$val'");
1544 }
69893cff
RGS
1545
1546 # restore original @INC
e22ea7cc
RF
1547 @INC = get_list("PERLDB_INC");
1548 @ini_INC = @INC;
1549
1550 # return pre/postprompt actions and typeahead buffer
1551 $pretype = [ get_list("PERLDB_PRETYPE") ];
1552 $pre = [ get_list("PERLDB_PRE") ];
1553 $post = [ get_list("PERLDB_POST") ];
1554 @typeahead = get_list( "PERLDB_TYPEAHEAD", @typeahead );
69893cff
RGS
1555} ## end if (exists $ENV{PERLDB_RESTART...
1556
1557=head2 SETTING UP THE TERMINAL
1558
1559Now, we'll decide how the debugger is going to interact with the user.
1560If there's no TTY, we set the debugger to run non-stop; there's not going
1561to be anyone there to enter commands.
1562
1563=cut
54d04a52 1564
d338d6fe 1565if ($notty) {
69893cff 1566 $runnonstop = 1;
2cbb2ee1 1567 share($runnonstop);
69893cff 1568}
d12a4851 1569
69893cff
RGS
1570=pod
1571
1572If there is a TTY, we have to determine who it belongs to before we can
1573proceed. If this is a slave editor or graphical debugger (denoted by
1574the first command-line switch being '-emacs'), we shift this off and
1575set C<$rl> to 0 (XXX ostensibly to do straight reads).
1576
1577=cut
1578
1579else {
e22ea7cc 1580
69893cff
RGS
1581 # Is Perl being run from a slave editor or graphical debugger?
1582 # If so, don't use readline, and set $slave_editor = 1.
e22ea7cc
RF
1583 $slave_editor =
1584 ( ( defined $main::ARGV[0] ) and ( $main::ARGV[0] eq '-emacs' ) );
1585 $rl = 0, shift(@main::ARGV) if $slave_editor;
1586
1587 #require Term::ReadLine;
d12a4851 1588
69893cff
RGS
1589=pod
1590
1591We then determine what the console should be on various systems:
1592
1593=over 4
1594
1595=item * Cygwin - We use C<stdin> instead of a separate device.
1596
1597=cut
1598
e22ea7cc
RF
1599 if ( $^O eq 'cygwin' ) {
1600
69893cff
RGS
1601 # /dev/tty is binary. use stdin for textmode
1602 undef $console;
1603 }
1604
1605=item * Unix - use C</dev/tty>.
1606
1607=cut
1608
e22ea7cc 1609 elsif ( -e "/dev/tty" ) {
69893cff
RGS
1610 $console = "/dev/tty";
1611 }
1612
1613=item * Windows or MSDOS - use C<con>.
1614
1615=cut
1616
e22ea7cc 1617 elsif ( $^O eq 'dos' or -e "con" or $^O eq 'MSWin32' ) {
69893cff
RGS
1618 $console = "con";
1619 }
1620
1621=item * MacOS - use C<Dev:Console:Perl Debug> if this is the MPW version; C<Dev:
be9a9b1d
AT
1622Console> if not.
1623
1624Note that Mac OS X returns C<darwin>, not C<MacOS>. Also note that the debugger doesn't do anything special for C<darwin>. Maybe it should.
69893cff
RGS
1625
1626=cut
1627
e22ea7cc
RF
1628 elsif ( $^O eq 'MacOS' ) {
1629 if ( $MacPerl::Version !~ /MPW/ ) {
1630 $console =
1631 "Dev:Console:Perl Debug"; # Separate window for application
69893cff
RGS
1632 }
1633 else {
1634 $console = "Dev:Console";
1635 }
1636 } ## end elsif ($^O eq 'MacOS')
1637
1638=item * VMS - use C<sys$command>.
1639
1640=cut
1641
1642 else {
e22ea7cc 1643
69893cff
RGS
1644 # everything else is ...
1645 $console = "sys\$command";
d12a4851 1646 }
69893cff
RGS
1647
1648=pod
1649
1650=back
1651
1652Several other systems don't use a specific console. We C<undef $console>
1653for those (Windows using a slave editor/graphical debugger, NetWare, OS/2
1654with a slave editor, Epoc).
1655
1656=cut
d12a4851 1657
e22ea7cc
RF
1658 if ( ( $^O eq 'MSWin32' ) and ( $slave_editor or defined $ENV{EMACS} ) ) {
1659
69893cff 1660 # /dev/tty is binary. use stdin for textmode
e22ea7cc
RF
1661 $console = undef;
1662 }
1663
1664 if ( $^O eq 'NetWare' ) {
d12a4851 1665
69893cff
RGS
1666 # /dev/tty is binary. use stdin for textmode
1667 $console = undef;
1668 }
d12a4851 1669
69893cff
RGS
1670 # In OS/2, we need to use STDIN to get textmode too, even though
1671 # it pretty much looks like Unix otherwise.
e22ea7cc
RF
1672 if ( defined $ENV{OS2_SHELL} and ( $slave_editor or $ENV{WINDOWID} ) )
1673 { # In OS/2
1674 $console = undef;
1675 }
1676
1677 # EPOC also falls into the 'got to use STDIN' camp.
1678 if ( $^O eq 'epoc' ) {
1679 $console = undef;
1680 }
d12a4851 1681
69893cff
RGS
1682=pod
1683
1684If there is a TTY hanging around from a parent, we use that as the console.
1685
1686=cut
1687
e22ea7cc 1688 $console = $tty if defined $tty;
d12a4851 1689
69893cff
RGS
1690=head2 SOCKET HANDLING
1691
1692The debugger is capable of opening a socket and carrying out a debugging
1693session over the socket.
1694
1695If C<RemotePort> was defined in the options, the debugger assumes that it
1696should try to start a debugging session on that port. It builds the socket
1697and then tries to connect the input and output filehandles to it.
1698
1699=cut
1700
1701 # Handle socket stuff.
e22ea7cc
RF
1702
1703 if ( defined $remoteport ) {
1704
69893cff
RGS
1705 # If RemotePort was defined in the options, connect input and output
1706 # to the socket.
e22ea7cc
RF
1707 require IO::Socket;
1708 $OUT = new IO::Socket::INET(
1709 Timeout => '10',
1710 PeerAddr => $remoteport,
1711 Proto => 'tcp',
69893cff 1712 );
e22ea7cc
RF
1713 if ( !$OUT ) { die "Unable to connect to remote host: $remoteport\n"; }
1714 $IN = $OUT;
69893cff
RGS
1715 } ## end if (defined $remoteport)
1716
1717=pod
1718
1719If no C<RemotePort> was defined, and we want to create a TTY on startup,
1720this is probably a situation where multiple debuggers are running (for example,
1721a backticked command that starts up another debugger). We create a new IN and
1722OUT filehandle, and do the necessary mojo to create a new TTY if we know how
1723and if we can.
1724
1725=cut
1726
1727 # Non-socket.
1728 else {
e22ea7cc 1729
69893cff
RGS
1730 # Two debuggers running (probably a system or a backtick that invokes
1731 # the debugger itself under the running one). create a new IN and OUT
e22ea7cc 1732 # filehandle, and do the necessary mojo to create a new tty if we
69893cff 1733 # know how, and we can.
e22ea7cc
RF
1734 create_IN_OUT(4) if $CreateTTY & 4;
1735 if ($console) {
1736
69893cff 1737 # If we have a console, check to see if there are separate ins and
cd1191f1 1738 # outs to open. (They are assumed identical if not.)
69893cff 1739
e22ea7cc
RF
1740 my ( $i, $o ) = split /,/, $console;
1741 $o = $i unless defined $o;
69893cff 1742
69893cff 1743 # read/write on in, or just read, or read on STDIN.
e22ea7cc
RF
1744 open( IN, "+<$i" )
1745 || open( IN, "<$i" )
1746 || open( IN, "<&STDIN" );
1747
69893cff
RGS
1748 # read/write/create/clobber out, or write/create/clobber out,
1749 # or merge with STDERR, or merge with STDOUT.
e22ea7cc
RF
1750 open( OUT, "+>$o" )
1751 || open( OUT, ">$o" )
1752 || open( OUT, ">&STDERR" )
1753 || open( OUT, ">&STDOUT" ); # so we don't dongle stdout
1754
1755 } ## end if ($console)
1756 elsif ( not defined $console ) {
1757
1758 # No console. Open STDIN.
1759 open( IN, "<&STDIN" );
1760
1761 # merge with STDERR, or with STDOUT.
1762 open( OUT, ">&STDERR" )
1763 || open( OUT, ">&STDOUT" ); # so we don't dongle stdout
1764 $console = 'STDIN/OUT';
69893cff
RGS
1765 } ## end elsif (not defined $console)
1766
1767 # Keep copies of the filehandles so that when the pager runs, it
1768 # can close standard input without clobbering ours.
e22ea7cc
RF
1769 $IN = \*IN, $OUT = \*OUT if $console or not defined $console;
1770 } ## end elsif (from if(defined $remoteport))
1771
1772 # Unbuffer DB::OUT. We need to see responses right away.
1773 my $previous = select($OUT);
1774 $| = 1; # for DB::OUT
1775 select($previous);
1776
1777 # Line info goes to debugger output unless pointed elsewhere.
1778 # Pointing elsewhere makes it possible for slave editors to
1779 # keep track of file and position. We have both a filehandle
1780 # and a I/O description to keep track of.
1781 $LINEINFO = $OUT unless defined $LINEINFO;
1782 $lineinfo = $console unless defined $lineinfo;
2cbb2ee1
RGS
1783 # share($LINEINFO); # <- unable to share globs
1784 share($lineinfo); #
e22ea7cc 1785
69893cff
RGS
1786=pod
1787
1788To finish initialization, we show the debugger greeting,
1789and then call the C<afterinit()> subroutine if there is one.
1790
1791=cut
d12a4851 1792
e22ea7cc
RF
1793 # Show the debugger greeting.
1794 $header =~ s/.Header: ([^,]+),v(\s+\S+\s+\S+).*$/$1$2/;
1795 unless ($runnonstop) {
1796 local $\ = '';
1797 local $, = '';
1798 if ( $term_pid eq '-1' ) {
1799 print $OUT "\nDaughter DB session started...\n";
1800 }
1801 else {
1802 print $OUT "\nLoading DB routines from $header\n";
1803 print $OUT (
1804 "Editor support ",
1805 $slave_editor ? "enabled" : "available", ".\n"
1806 );
1807 print $OUT
69893cff
RGS
1808"\nEnter h or `h h' for help, or `$doccmd perldebug' for more help.\n\n";
1809 } ## end else [ if ($term_pid eq '-1')
1810 } ## end unless ($runnonstop)
1811} ## end else [ if ($notty)
1812
1813# XXX This looks like a bug to me.
1814# Why copy to @ARGS and then futz with @args?
d338d6fe 1815@ARGS = @ARGV;
1816for (@args) {
69893cff
RGS
1817 # Make sure backslashes before single quotes are stripped out, and
1818 # keep args unless they are numeric (XXX why?)
e22ea7cc
RF
1819 # s/\'/\\\'/g; # removed while not justified understandably
1820 # s/(.*)/'$1'/ unless /^-?[\d.]+$/; # ditto
d338d6fe 1821}
1822
e22ea7cc 1823# If there was an afterinit() sub defined, call it. It will get
69893cff 1824# executed in our scope, so it can fiddle with debugger globals.
e22ea7cc 1825if ( defined &afterinit ) { # May be defined in $rcfile
69893cff 1826 &afterinit();
d338d6fe 1827}
e22ea7cc 1828
69893cff 1829# Inform us about "Stack dump during die enabled ..." in dieLevel().
43aed9ee
IZ
1830$I_m_init = 1;
1831
d338d6fe 1832############################################################ Subroutines
1833
69893cff
RGS
1834=head1 SUBROUTINES
1835
1836=head2 DB
1837
1838This gigantic subroutine is the heart of the debugger. Called before every
1839statement, its job is to determine if a breakpoint has been reached, and
1840stop if so; read commands from the user, parse them, and execute
1841them, and hen send execution off to the next statement.
1842
1843Note that the order in which the commands are processed is very important;
1844some commands earlier in the loop will actually alter the C<$cmd> variable
be9a9b1d 1845to create other commands to be executed later. This is all highly I<optimized>
69893cff
RGS
1846but can be confusing. Check the comments for each C<$cmd ... && do {}> to
1847see what's happening in any given command.
1848
1849=cut
1850
d338d6fe 1851sub DB {
69893cff 1852
2cbb2ee1
RGS
1853 # lock the debugger and get the thread id for the prompt
1854 lock($DBGR);
1855 my $tid;
1856 if ($ENV{PERL5DB_THREADED}) {
878090d5 1857 $tid = eval { "[".threads->tid."]" };
2cbb2ee1
RGS
1858 }
1859
69893cff 1860 # Check for whether we should be running continuously or not.
36477c24 1861 # _After_ the perl program is compiled, $single is set to 1:
e22ea7cc
RF
1862 if ( $single and not $second_time++ ) {
1863
69893cff 1864 # Options say run non-stop. Run until we get an interrupt.
e22ea7cc
RF
1865 if ($runnonstop) { # Disable until signal
1866 # If there's any call stack in place, turn off single
1867 # stepping into subs throughout the stack.
1868 for ( $i = 0 ; $i <= $stack_depth ; ) {
1869 $stack[ $i++ ] &= ~1;
1870 }
1871
69893cff 1872 # And we are now no longer in single-step mode.
e22ea7cc 1873 $single = 0;
69893cff
RGS
1874
1875 # If we simply returned at this point, we wouldn't get
1876 # the trace info. Fall on through.
e22ea7cc 1877 # return;
69893cff
RGS
1878 } ## end if ($runnonstop)
1879
e22ea7cc
RF
1880 elsif ($ImmediateStop) {
1881
1882 # We are supposed to stop here; XXX probably a break.
1883 $ImmediateStop = 0; # We've processed it; turn it off
1884 $signal = 1; # Simulate an interrupt to force
1885 # us into the command loop
69893cff
RGS
1886 }
1887 } ## end if ($single and not $second_time...
1888
1889 # If we're in single-step mode, or an interrupt (real or fake)
1890 # has occurred, turn off non-stop mode.
1891 $runnonstop = 0 if $single or $signal;
1892
1893 # Preserve current values of $@, $!, $^E, $,, $/, $\, $^W.
1894 # The code being debugged may have altered them.
d338d6fe 1895 &save;
69893cff
RGS
1896
1897 # Since DB::DB gets called after every line, we can use caller() to
1898 # figure out where we last were executing. Sneaky, eh? This works because
e22ea7cc 1899 # caller is returning all the extra information when called from the
69893cff 1900 # debugger.
e22ea7cc 1901 local ( $package, $filename, $line ) = caller;
471505cc 1902 local $filename_ini = $filename;
69893cff
RGS
1903
1904 # set up the context for DB::eval, so it can properly execute
1905 # code on behalf of the user. We add the package in so that the
1906 # code is eval'ed in the proper package (not in the debugger!).
1907 local $usercontext =
e22ea7cc 1908 '($@, $!, $^E, $,, $/, $\, $^W) = @saved;' . "package $package;";
69893cff
RGS
1909
1910 # Create an alias to the active file magical array to simplify
1911 # the code here.
e22ea7cc 1912 local (*dbline) = $main::{ '_<' . $filename };
aa057b67
CN
1913
1914 # we need to check for pseudofiles on Mac OS (these are files
1915 # not attached to a filename, but instead stored in Dev:Pseudo)
e22ea7cc
RF
1916 if ( $^O eq 'MacOS' && $#dbline < 0 ) {
1917 $filename_ini = $filename = 'Dev:Pseudo';
1918 *dbline = $main::{ '_<' . $filename };
aa057b67
CN
1919 }
1920
69893cff 1921 # Last line in the program.
471505cc 1922 local $max = $#dbline;
69893cff
RGS
1923
1924 # if we have something here, see if we should break.
e22ea7cc
RF
1925 if ( $dbline{$line}
1926 && ( ( $stop, $action ) = split( /\0/, $dbline{$line} ) ) )
1927 {
1928
69893cff 1929 # Stop if the stop criterion says to just stop.
e22ea7cc 1930 if ( $stop eq '1' ) {
69893cff
RGS
1931 $signal |= 1;
1932 }
e22ea7cc 1933
69893cff
RGS
1934 # It's a conditional stop; eval it in the user's context and
1935 # see if we should stop. If so, remove the one-time sigil.
1936 elsif ($stop) {
e22ea7cc 1937 $evalarg = "\$DB::signal |= 1 if do {$stop}";
69893cff
RGS
1938 &eval;
1939 $dbline{$line} =~ s/;9($|\0)/$1/;
1940 }
1941 } ## end if ($dbline{$line} && ...
1942
1943 # Preserve the current stop-or-not, and see if any of the W
1944 # (watch expressions) has changed.
36477c24 1945 my $was_signal = $signal;
69893cff
RGS
1946
1947 # If we have any watch expressions ...
e22ea7cc
RF
1948 if ( $trace & 2 ) {
1949 for ( my $n = 0 ; $n <= $#to_watch ; $n++ ) {
1950 $evalarg = $to_watch[$n];
1951 local $onetimeDump; # Tell DB::eval() to not output results
69893cff
RGS
1952
1953 # Fix context DB::eval() wants to return an array, but
1954 # we need a scalar here.
e22ea7cc
RF
1955 my ($val) = join( "', '", &eval );
1956 $val = ( ( defined $val ) ? "'$val'" : 'undef' );
69893cff
RGS
1957
1958 # Did it change?
e22ea7cc
RF
1959 if ( $val ne $old_watch[$n] ) {
1960
69893cff 1961 # Yep! Show the difference, and fake an interrupt.
e22ea7cc
RF
1962 $signal = 1;
1963 print $OUT <<EOP;
405ff068 1964Watchpoint $n:\t$to_watch[$n] changed:
69893cff
RGS
1965 old value:\t$old_watch[$n]
1966 new value:\t$val
6027b9a3 1967EOP
e22ea7cc 1968 $old_watch[$n] = $val;
69893cff
RGS
1969 } ## end if ($val ne $old_watch...
1970 } ## end for (my $n = 0 ; $n <= ...
1971 } ## end if ($trace & 2)
1972
1973=head2 C<watchfunction()>
1974
1975C<watchfunction()> is a function that can be defined by the user; it is a
1976function which will be run on each entry to C<DB::DB>; it gets the
1977current package, filename, and line as its parameters.
1978
1979The watchfunction can do anything it likes; it is executing in the
1980debugger's context, so it has access to all of the debugger's internal
1981data structures and functions.
1982
1983C<watchfunction()> can control the debugger's actions. Any of the following
1984will cause the debugger to return control to the user's program after
1985C<watchfunction()> executes:
1986
1987=over 4
1988
be9a9b1d
AT
1989=item *
1990
1991Returning a false value from the C<watchfunction()> itself.
1992
1993=item *
1994
1995Altering C<$single> to a false value.
1996
1997=item *
69893cff 1998
be9a9b1d 1999Altering C<$signal> to a false value.
69893cff 2000
be9a9b1d 2001=item *
69893cff 2002
be9a9b1d 2003Turning off the C<4> bit in C<$trace> (this also disables the
69893cff
RGS
2004check for C<watchfunction()>. This can be done with
2005
2006 $trace &= ~4;
2007
2008=back
2009
2010=cut
2011
e22ea7cc 2012 # If there's a user-defined DB::watchfunction, call it with the
69893cff
RGS
2013 # current package, filename, and line. The function executes in
2014 # the DB:: package.
e22ea7cc
RF
2015 if ( $trace & 4 ) { # User-installed watch
2016 return
2017 if watchfunction( $package, $filename, $line )
2018 and not $single
2019 and not $was_signal
2020 and not( $trace & ~4 );
69893cff
RGS
2021 } ## end if ($trace & 4)
2022
e22ea7cc 2023 # Pick up any alteration to $signal in the watchfunction, and
69893cff 2024 # turn off the signal now.
6027b9a3 2025 $was_signal = $signal;
69893cff
RGS
2026 $signal = 0;
2027
2028=head2 GETTING READY TO EXECUTE COMMANDS
2029
2030The debugger decides to take control if single-step mode is on, the
2031C<t> command was entered, or the user generated a signal. If the program
2032has fallen off the end, we set things up so that entering further commands
2033won't cause trouble, and we say that the program is over.
2034
2035=cut
2036
2037 # Check to see if we should grab control ($single true,
2038 # trace set appropriately, or we got a signal).
e22ea7cc
RF
2039 if ( $single || ( $trace & 1 ) || $was_signal ) {
2040
69893cff 2041 # Yes, grab control.
e22ea7cc
RF
2042 if ($slave_editor) {
2043
69893cff 2044 # Tell the editor to update its position.
e22ea7cc
RF
2045 $position = "\032\032$filename:$line:0\n";
2046 print_lineinfo($position);
2047 }
69893cff
RGS
2048
2049=pod
2050
2051Special check: if we're in package C<DB::fake>, we've gone through the
2052C<END> block at least once. We set up everything so that we can continue
2053to enter commands and have a valid context to be in.
2054
2055=cut
2056
e22ea7cc 2057 elsif ( $package eq 'DB::fake' ) {
69893cff 2058
69893cff 2059 # Fallen off the end already.
e22ea7cc
RF
2060 $term || &setterm;
2061 print_help(<<EOP);
405ff068 2062Debugged program terminated. Use B<q> to quit or B<R> to restart,
6b27b0a0
BD
2063 use B<o> I<inhibit_exit> to avoid stopping after program termination,
2064 B<h q>, B<h R> or B<h o> to get additional info.
405ff068 2065EOP
e22ea7cc 2066
69893cff 2067 # Set the DB::eval context appropriately.
e22ea7cc
RF
2068 $package = 'main';
2069 $usercontext =
2070 '($@, $!, $^E, $,, $/, $\, $^W) = @saved;'
2071 . "package $package;"; # this won't let them modify, alas
69893cff 2072 } ## end elsif ($package eq 'DB::fake')
e219e2fb 2073
69893cff 2074=pod
e219e2fb 2075
69893cff
RGS
2076If the program hasn't finished executing, we scan forward to the
2077next executable line, print that out, build the prompt from the file and line
2078number information, and print that.
e219e2fb 2079
69893cff
RGS
2080=cut
2081
e22ea7cc
RF
2082 else {
2083
69893cff
RGS
2084 # Still somewhere in the midst of execution. Set up the
2085 # debugger prompt.
2086 $sub =~ s/\'/::/; # Swap Perl 4 package separators (') to
e22ea7cc 2087 # Perl 5 ones (sorry, we don't print Klingon
69893cff
RGS
2088 #module names)
2089
e22ea7cc
RF
2090 $prefix = $sub =~ /::/ ? "" : "${'package'}::";
2091 $prefix .= "$sub($filename:";
2092 $after = ( $dbline[$line] =~ /\n$/ ? '' : "\n" );
69893cff
RGS
2093
2094 # Break up the prompt if it's really long.
e22ea7cc
RF
2095 if ( length($prefix) > 30 ) {
2096 $position = "$prefix$line):\n$line:\t$dbline[$line]$after";
2097 $prefix = "";
2098 $infix = ":\t";
2099 }
2100 else {
2101 $infix = "):\t";
2102 $position = "$prefix$line$infix$dbline[$line]$after";
2103 }
69893cff
RGS
2104
2105 # Print current line info, indenting if necessary.
e22ea7cc
RF
2106 if ($frame) {
2107 print_lineinfo( ' ' x $stack_depth,
2108 "$line:\t$dbline[$line]$after" );
2109 }
2110 else {
2111 print_lineinfo($position);
2112 }
69893cff
RGS
2113
2114 # Scan forward, stopping at either the end or the next
2115 # unbreakable line.
e22ea7cc
RF
2116 for ( $i = $line + 1 ; $i <= $max && $dbline[$i] == 0 ; ++$i )
2117 { #{ vi
69893cff
RGS
2118
2119 # Drop out on null statements, block closers, and comments.
2120 last if $dbline[$i] =~ /^\s*[\;\}\#\n]/;
2121
2122 # Drop out if the user interrupted us.
2123 last if $signal;
2124
2125 # Append a newline if the line doesn't have one. Can happen
2126 # in eval'ed text, for instance.
e22ea7cc 2127 $after = ( $dbline[$i] =~ /\n$/ ? '' : "\n" );
69893cff
RGS
2128
2129 # Next executable line.
2130 $incr_pos = "$prefix$i$infix$dbline[$i]$after";
2131 $position .= $incr_pos;
2132 if ($frame) {
e22ea7cc 2133
69893cff 2134 # Print it indented if tracing is on.
e22ea7cc
RF
2135 print_lineinfo( ' ' x $stack_depth,
2136 "$i:\t$dbline[$i]$after" );
69893cff
RGS
2137 }
2138 else {
2139 print_lineinfo($incr_pos);
2140 }
2141 } ## end for ($i = $line + 1 ; $i...
2142 } ## end else [ if ($slave_editor)
2143 } ## end if ($single || ($trace...
2144
2145=pod
2146
2147If there's an action to be executed for the line we stopped at, execute it.
2148If there are any preprompt actions, execute those as well.
e219e2fb
RF
2149
2150=cut
2151
69893cff
RGS
2152 # If there's an action, do it now.
2153 $evalarg = $action, &eval if $action;
e219e2fb 2154
69893cff
RGS
2155 # Are we nested another level (e.g., did we evaluate a function
2156 # that had a breakpoint in it at the debugger prompt)?
e22ea7cc
RF
2157 if ( $single || $was_signal ) {
2158
69893cff 2159 # Yes, go down a level.
e22ea7cc 2160 local $level = $level + 1;
69893cff
RGS
2161
2162 # Do any pre-prompt actions.
e22ea7cc
RF
2163 foreach $evalarg (@$pre) {
2164 &eval;
2165 }
69893cff
RGS
2166
2167 # Complain about too much recursion if we passed the limit.
e22ea7cc 2168 print $OUT $stack_depth . " levels deep in subroutine calls!\n"
69893cff
RGS
2169 if $single & 4;
2170
2171 # The line we're currently on. Set $incr to -1 to stay here
2172 # until we get a command that tells us to advance.
e22ea7cc
RF
2173 $start = $line;
2174 $incr = -1; # for backward motion.
69893cff
RGS
2175
2176 # Tack preprompt debugger actions ahead of any actual input.
e22ea7cc 2177 @typeahead = ( @$pretype, @typeahead );
69893cff
RGS
2178
2179=head2 WHERE ARE WE?
2180
2181XXX Relocate this section?
2182
2183The debugger normally shows the line corresponding to the current line of
2184execution. Sometimes, though, we want to see the next line, or to move elsewhere
2185in the file. This is done via the C<$incr>, C<$start>, and C<$max> variables.
2186
be9a9b1d
AT
2187C<$incr> controls by how many lines the I<current> line should move forward
2188after a command is executed. If set to -1, this indicates that the I<current>
69893cff
RGS
2189line shouldn't change.
2190
be9a9b1d 2191C<$start> is the I<current> line. It is used for things like knowing where to
69893cff
RGS
2192move forwards or backwards from when doing an C<L> or C<-> command.
2193
2194C<$max> tells the debugger where the last line of the current file is. It's
2195used to terminate loops most often.
2196
2197=head2 THE COMMAND LOOP
2198
2199Most of C<DB::DB> is actually a command parsing and dispatch loop. It comes
2200in two parts:
2201
2202=over 4
2203
be9a9b1d
AT
2204=item *
2205
2206The outer part of the loop, starting at the C<CMD> label. This loop
69893cff
RGS
2207reads a command and then executes it.
2208
be9a9b1d
AT
2209=item *
2210
2211The inner part of the loop, starting at the C<PIPE> label. This part
69893cff
RGS
2212is wholly contained inside the C<CMD> block and only executes a command.
2213Used to handle commands running inside a pager.
2214
2215=back
2216
2217So why have two labels to restart the loop? Because sometimes, it's easier to
2218have a command I<generate> another command and then re-execute the loop to do
2219the new command. This is faster, but perhaps a bit more convoluted.
2220
2221=cut
2222
2223 # The big command dispatch loop. It keeps running until the
2224 # user yields up control again.
2225 #
2226 # If we have a terminal for input, and we get something back
2227 # from readline(), keep on processing.
e22ea7cc
RF
2228 CMD:
2229 while (
2230
69893cff 2231 # We have a terminal, or can get one ...
e22ea7cc
RF
2232 ( $term || &setterm ),
2233
69893cff 2234 # ... and it belogs to this PID or we get one for this PID ...
e22ea7cc
RF
2235 ( $term_pid == $$ or resetterm(1) ),
2236
69893cff 2237 # ... and we got a line of command input ...
e22ea7cc
RF
2238 defined(
2239 $cmd = &readline(
2cbb2ee1 2240 "$pidprompt $tid DB"
e22ea7cc
RF
2241 . ( '<' x $level )
2242 . ( $#hist + 1 )
2243 . ( '>' x $level ) . " "
69893cff
RGS
2244 )
2245 )
2246 )
2247 {
e22ea7cc 2248
2cbb2ee1 2249 share($cmd);
69893cff
RGS
2250 # ... try to execute the input as debugger commands.
2251
2252 # Don't stop running.
2253 $single = 0;
2254
2255 # No signal is active.
2256 $signal = 0;
2257
2258 # Handle continued commands (ending with \):
e22ea7cc
RF
2259 $cmd =~ s/\\$/\n/ && do {
2260 $cmd .= &readline(" cont: ");
2261 redo CMD;
2262 };
69893cff
RGS
2263
2264=head4 The null command
2265
be9a9b1d 2266A newline entered by itself means I<re-execute the last command>. We grab the
69893cff
RGS
2267command out of C<$laststep> (where it was recorded previously), and copy it
2268back into C<$cmd> to be executed below. If there wasn't any previous command,
2269we'll do nothing below (no command will match). If there was, we also save it
2270in the command history and fall through to allow the command parsing to pick
2271it up.
2272
2273=cut
2274
2275 # Empty input means repeat the last command.
e22ea7cc
RF
2276 $cmd =~ /^$/ && ( $cmd = $laststep );
2277 chomp($cmd); # get rid of the annoying extra newline
2278 push( @hist, $cmd ) if length($cmd) > 1;
2279 push( @truehist, $cmd );
2cbb2ee1
RGS
2280 share(@hist);
2281 share(@truehist);
e22ea7cc
RF
2282
2283 # This is a restart point for commands that didn't arrive
2284 # via direct user input. It allows us to 'redo PIPE' to
2285 # re-execute command processing without reading a new command.
69893cff 2286 PIPE: {
e22ea7cc
RF
2287 $cmd =~ s/^\s+//s; # trim annoying leading whitespace
2288 $cmd =~ s/\s+$//s; # trim annoying trailing whitespace
2289 ($i) = split( /\s+/, $cmd );
69893cff
RGS
2290
2291=head3 COMMAND ALIASES
2292
2293The debugger can create aliases for commands (these are stored in the
2294C<%alias> hash). Before a command is executed, the command loop looks it up
2295in the alias hash and substitutes the contents of the alias for the command,
2296completely replacing it.
2297
2298=cut
2299
2300 # See if there's an alias for the command, and set it up if so.
e22ea7cc
RF
2301 if ( $alias{$i} ) {
2302
69893cff
RGS
2303 # Squelch signal handling; we want to keep control here
2304 # if something goes loco during the alias eval.
2305 local $SIG{__DIE__};
2306 local $SIG{__WARN__};
2307
2308 # This is a command, so we eval it in the DEBUGGER's
2309 # scope! Otherwise, we can't see the special debugger
2310 # variables, or get to the debugger's subs. (Well, we
2311 # _could_, but why make it even more complicated?)
2312 eval "\$cmd =~ $alias{$i}";
2313 if ($@) {
2314 local $\ = '';
2315 print $OUT "Couldn't evaluate `$i' alias: $@";
2316 next CMD;
2317 }
2318 } ## end if ($alias{$i})
2319
2320=head3 MAIN-LINE COMMANDS
2321
2322All of these commands work up to and after the program being debugged has
2323terminated.
2324
2325=head4 C<q> - quit
2326
2327Quit the debugger. This entails setting the C<$fall_off_end> flag, so we don't
2328try to execute further, cleaning any restart-related stuff out of the
2329environment, and executing with the last value of C<$?>.
2330
2331=cut
2332
2333 $cmd =~ /^q$/ && do {
2334 $fall_off_end = 1;
2335 clean_ENV();
2336 exit $?;
2337 };
2338
2339=head4 C<t> - trace
2340
2341Turn tracing on or off. Inverts the appropriate bit in C<$trace> (q.v.).
2342
2343=cut
2344
e22ea7cc
RF
2345 $cmd =~ /^t$/ && do {
2346 $trace ^= 1;
2347 local $\ = '';
2348 print $OUT "Trace = "
2349 . ( ( $trace & 1 ) ? "on" : "off" ) . "\n";
2350 next CMD;
2351 };
69893cff
RGS
2352
2353=head4 C<S> - list subroutines matching/not matching a pattern
2354
2355Walks through C<%sub>, checking to see whether or not to print the name.
2356
2357=cut
2358
e22ea7cc 2359 $cmd =~ /^S(\s+(!)?(.+))?$/ && do {
69893cff 2360
e22ea7cc 2361 $Srev = defined $2; # Reverse scan?
69893cff
RGS
2362 $Spatt = $3; # The pattern (if any) to use.
2363 $Snocheck = !defined $1; # No args - print all subs.
2364
2365 # Need to make these sane here.
e22ea7cc
RF
2366 local $\ = '';
2367 local $, = '';
69893cff
RGS
2368
2369 # Search through the debugger's magical hash of subs.
2370 # If $nocheck is true, just print the sub name.
2371 # Otherwise, check it against the pattern. We then use
2372 # the XOR trick to reverse the condition as required.
e22ea7cc
RF
2373 foreach $subname ( sort( keys %sub ) ) {
2374 if ( $Snocheck or $Srev ^ ( $subname =~ /$Spatt/ ) ) {
2375 print $OUT $subname, "\n";
2376 }
2377 }
2378 next CMD;
2379 };
69893cff
RGS
2380
2381=head4 C<X> - list variables in current package
2382
2383Since the C<V> command actually processes this, just change this to the
2384appropriate C<V> command and fall through.
2385
2386=cut
2387
e22ea7cc 2388 $cmd =~ s/^X\b/V $package/;
69893cff
RGS
2389
2390=head4 C<V> - list variables
2391
2392Uses C<dumpvar.pl> to dump out the current values for selected variables.
2393
2394=cut
2395
2396 # Bare V commands get the currently-being-debugged package
2397 # added.
e22ea7cc
RF
2398 $cmd =~ /^V$/ && do {
2399 $cmd = "V $package";
2400 };
69893cff
RGS
2401
2402 # V - show variables in package.
2403 $cmd =~ /^V\b\s*(\S+)\s*(.*)/ && do {
e22ea7cc 2404
69893cff
RGS
2405 # Save the currently selected filehandle and
2406 # force output to debugger's filehandle (dumpvar
2407 # just does "print" for output).
e22ea7cc 2408 local ($savout) = select($OUT);
69893cff
RGS
2409
2410 # Grab package name and variables to dump.
e22ea7cc
RF
2411 $packname = $1;
2412 @vars = split( ' ', $2 );
69893cff
RGS
2413
2414 # If main::dumpvar isn't here, get it.
e81465be 2415 do 'dumpvar.pl' || die $@ unless defined &main::dumpvar;
e22ea7cc
RF
2416 if ( defined &main::dumpvar ) {
2417
69893cff
RGS
2418 # We got it. Turn off subroutine entry/exit messages
2419 # for the moment, along with return values.
e22ea7cc
RF
2420 local $frame = 0;
2421 local $doret = -2;
69893cff
RGS
2422
2423 # must detect sigpipe failures - not catching
2424 # then will cause the debugger to die.
2425 eval {
2426 &main::dumpvar(
2427 $packname,
2428 defined $option{dumpDepth}
e22ea7cc
RF
2429 ? $option{dumpDepth}
2430 : -1, # assume -1 unless specified
69893cff 2431 @vars
e22ea7cc
RF
2432 );
2433 };
2434
2435 # The die doesn't need to include the $@, because
2436 # it will automatically get propagated for us.
2437 if ($@) {
2438 die unless $@ =~ /dumpvar print failed/;
2439 }
2440 } ## end if (defined &main::dumpvar)
2441 else {
2442
2443 # Couldn't load dumpvar.
2444 print $OUT "dumpvar.pl not available.\n";
2445 }
69893cff 2446
69893cff 2447 # Restore the output filehandle, and go round again.
e22ea7cc
RF
2448 select($savout);
2449 next CMD;
2450 };
69893cff
RGS
2451
2452=head4 C<x> - evaluate and print an expression
2453
2454Hands the expression off to C<DB::eval>, setting it up to print the value
2455via C<dumpvar.pl> instead of just printing it directly.
2456
2457=cut
2458
e22ea7cc
RF
2459 $cmd =~ s/^x\b/ / && do { # Remainder gets done by DB::eval()
2460 $onetimeDump = 'dump'; # main::dumpvar shows the output
69893cff
RGS
2461
2462 # handle special "x 3 blah" syntax XXX propagate
2463 # doc back to special variables.
e22ea7cc
RF
2464 if ( $cmd =~ s/^\s*(\d+)(?=\s)/ / ) {
2465 $onetimedumpDepth = $1;
2466 }
2467 };
69893cff
RGS
2468
2469=head4 C<m> - print methods
2470
2471Just uses C<DB::methods> to determine what methods are available.
2472
2473=cut
2474
e22ea7cc
RF
2475 $cmd =~ s/^m\s+([\w:]+)\s*$/ / && do {
2476 methods($1);
2477 next CMD;
2478 };
69893cff
RGS
2479
2480 # m expr - set up DB::eval to do the work
e22ea7cc
RF
2481 $cmd =~ s/^m\b/ / && do { # Rest gets done by DB::eval()
2482 $onetimeDump = 'methods'; # method output gets used there
2483 };
69893cff
RGS
2484
2485=head4 C<f> - switch files
2486
2487=cut
2488
e22ea7cc
RF
2489 $cmd =~ /^f\b\s*(.*)/ && do {
2490 $file = $1;
2491 $file =~ s/\s+$//;
69893cff
RGS
2492
2493 # help for no arguments (old-style was return from sub).
e22ea7cc
RF
2494 if ( !$file ) {
2495 print $OUT
2496 "The old f command is now the r command.\n"; # hint
2497 print $OUT "The new f command switches filenames.\n";
2498 next CMD;
2499 } ## end if (!$file)
69893cff
RGS
2500
2501 # if not in magic file list, try a close match.
e22ea7cc
RF
2502 if ( !defined $main::{ '_<' . $file } ) {
2503 if ( ($try) = grep( m#^_<.*$file#, keys %main:: ) ) {
2504 {
2505 $try = substr( $try, 2 );
2506 print $OUT "Choosing $try matching `$file':\n";
2507 $file = $try;
2508 }
2509 } ## end if (($try) = grep(m#^_<.*$file#...
2510 } ## end if (!defined $main::{ ...
69893cff
RGS
2511
2512 # If not successfully switched now, we failed.
e22ea7cc
RF
2513 if ( !defined $main::{ '_<' . $file } ) {
2514 print $OUT "No file matching `$file' is loaded.\n";
2515 next CMD;
2516 }
69893cff 2517
e22ea7cc
RF
2518 # We switched, so switch the debugger internals around.
2519 elsif ( $file ne $filename ) {
2520 *dbline = $main::{ '_<' . $file };
2521 $max = $#dbline;
2522 $filename = $file;
2523 $start = 1;
2524 $cmd = "l";
2525 } ## end elsif ($file ne $filename)
2526
2527 # We didn't switch; say we didn't.
2528 else {
2529 print $OUT "Already in $file.\n";
2530 next CMD;
2531 }
2532 };
69893cff
RGS
2533
2534=head4 C<.> - return to last-executed line.
2535
2536We set C<$incr> to -1 to indicate that the debugger shouldn't move ahead,
2537and then we look up the line in the magical C<%dbline> hash.
2538
2539=cut
2540
2541 # . command.
e22ea7cc
RF
2542 $cmd =~ /^\.$/ && do {
2543 $incr = -1; # stay at current line
69893cff
RGS
2544
2545 # Reset everything to the old location.
e22ea7cc
RF
2546 $start = $line;
2547 $filename = $filename_ini;
2548 *dbline = $main::{ '_<' . $filename };
2549 $max = $#dbline;
69893cff
RGS
2550
2551 # Now where are we?
e22ea7cc
RF
2552 print_lineinfo($position);
2553 next CMD;
2554 };
69893cff
RGS
2555
2556=head4 C<-> - back one window
2557
2558We change C<$start> to be one window back; if we go back past the first line,
2559we set it to be the first line. We ser C<$incr> to put us back at the
2560currently-executing line, and then put a C<l $start +> (list one window from
2561C<$start>) in C<$cmd> to be executed later.
2562
2563=cut
2564
2565 # - - back a window.
e22ea7cc
RF
2566 $cmd =~ /^-$/ && do {
2567
69893cff 2568 # back up by a window; go to 1 if back too far.
e22ea7cc
RF
2569 $start -= $incr + $window + 1;
2570 $start = 1 if $start <= 0;
2571 $incr = $window - 1;
69893cff
RGS
2572
2573 # Generate and execute a "l +" command (handled below).
e22ea7cc
RF
2574 $cmd = 'l ' . ($start) . '+';
2575 };
69893cff
RGS
2576
2577=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>, {, {{>
2578
2579In Perl 5.8.0, a realignment of the commands was done to fix up a number of
2580problems, most notably that the default case of several commands destroying
2581the user's work in setting watchpoints, actions, etc. We wanted, however, to
2582retain the old commands for those who were used to using them or who preferred
2583them. At this point, we check for the new commands and call C<cmd_wrapper> to
2584deal with them instead of processing them in-line.
2585
2586=cut
2587
2588 # All of these commands were remapped in perl 5.8.0;
e22ea7cc 2589 # we send them off to the secondary dispatcher (see below).
2cbb2ee1 2590 $cmd =~ /^([aAbBeEhilLMoOPvwW]\b|[<>\{]{1,2})\s*(.*)/so && do {
e22ea7cc
RF
2591 &cmd_wrapper( $1, $2, $line );
2592 next CMD;
2593 };
69893cff
RGS
2594
2595=head4 C<y> - List lexicals in higher scope
2596
2597Uses C<PadWalker> to find the lexicals supplied as arguments in a scope
2598above the current one and then displays then using C<dumpvar.pl>.
2599
2600=cut
2601
2602 $cmd =~ /^y(?:\s+(\d*)\s*(.*))?$/ && do {
2603
2604 # See if we've got the necessary support.
2605 eval { require PadWalker; PadWalker->VERSION(0.08) }
2606 or &warn(
2607 $@ =~ /locate/
2608 ? "PadWalker module not found - please install\n"
2609 : $@
2610 )
2611 and next CMD;
2612
2613 # Load up dumpvar if we don't have it. If we can, that is.
e81465be 2614 do 'dumpvar.pl' || die $@ unless defined &main::dumpvar;
69893cff
RGS
2615 defined &main::dumpvar
2616 or print $OUT "dumpvar.pl not available.\n"
2617 and next CMD;
2618
2619 # Got all the modules we need. Find them and print them.
e22ea7cc 2620 my @vars = split( ' ', $2 || '' );
69893cff
RGS
2621
2622 # Find the pad.
e22ea7cc 2623 my $h = eval { PadWalker::peek_my( ( $1 || 0 ) + 1 ) };
69893cff
RGS
2624
2625 # Oops. Can't find it.
2626 $@ and $@ =~ s/ at .*//, &warn($@), next CMD;
2627
2628 # Show the desired vars with dumplex().
2629 my $savout = select($OUT);
2630
2631 # Have dumplex dump the lexicals.
e22ea7cc 2632 dumpvar::dumplex( $_, $h->{$_},
69893cff 2633 defined $option{dumpDepth} ? $option{dumpDepth} : -1,
e22ea7cc
RF
2634 @vars )
2635 for sort keys %$h;
69893cff
RGS
2636 select($savout);
2637 next CMD;
2638 };
2639
2640=head3 COMMANDS NOT WORKING AFTER PROGRAM ENDS
2641
2642All of the commands below this point don't work after the program being
2643debugged has ended. All of them check to see if the program has ended; this
2644allows the commands to be relocated without worrying about a 'line of
2645demarcation' above which commands can be entered anytime, and below which
2646they can't.
2647
2648=head4 C<n> - single step, but don't trace down into subs
2649
2650Done by setting C<$single> to 2, which forces subs to execute straight through
be9a9b1d 2651when entered (see C<DB::sub>). We also save the C<n> command in C<$laststep>,
69893cff
RGS
2652so a null command knows what to re-execute.
2653
2654=cut
2655
e22ea7cc 2656 # n - next
69893cff
RGS
2657 $cmd =~ /^n$/ && do {
2658 end_report(), next CMD if $finished and $level <= 1;
e22ea7cc 2659
69893cff
RGS
2660 # Single step, but don't enter subs.
2661 $single = 2;
e22ea7cc 2662
69893cff 2663 # Save for empty command (repeat last).
e22ea7cc
RF
2664 $laststep = $cmd;
2665 last CMD;
2666 };
69893cff
RGS
2667
2668=head4 C<s> - single-step, entering subs
2669
be9a9b1d 2670Sets C<$single> to 1, which causes C<DB::sub> to continue tracing inside
69893cff
RGS
2671subs. Also saves C<s> as C<$lastcmd>.
2672
2673=cut
2674
2675 # s - single step.
2676 $cmd =~ /^s$/ && do {
e22ea7cc 2677
69893cff
RGS
2678 # Get out and restart the command loop if program
2679 # has finished.
e22ea7cc
RF
2680 end_report(), next CMD if $finished and $level <= 1;
2681
69893cff 2682 # Single step should enter subs.
e22ea7cc
RF
2683 $single = 1;
2684
69893cff 2685 # Save for empty command (repeat last).
e22ea7cc
RF
2686 $laststep = $cmd;
2687 last CMD;
2688 };
69893cff
RGS
2689
2690=head4 C<c> - run continuously, setting an optional breakpoint
2691
2692Most of the code for this command is taken up with locating the optional
2693breakpoint, which is either a subroutine name or a line number. We set
2694the appropriate one-time-break in C<@dbline> and then turn off single-stepping
2695in this and all call levels above this one.
2696
2697=cut
2698
2699 # c - start continuous execution.
2700 $cmd =~ /^c\b\s*([\w:]*)\s*$/ && do {
e22ea7cc 2701
69893cff
RGS
2702 # Hey, show's over. The debugged program finished
2703 # executing already.
2704 end_report(), next CMD if $finished and $level <= 1;
2705
2706 # Capture the place to put a one-time break.
2707 $subname = $i = $1;
2708
e22ea7cc
RF
2709 # Probably not needed, since we finish an interactive
2710 # sub-session anyway...
2711 # local $filename = $filename;
2712 # local *dbline = *dbline; # XXX Would this work?!
69893cff
RGS
2713 #
2714 # The above question wonders if localizing the alias
2715 # to the magic array works or not. Since it's commented
2716 # out, we'll just leave that to speculation for now.
2717
2718 # If the "subname" isn't all digits, we'll assume it
2719 # is a subroutine name, and try to find it.
e22ea7cc
RF
2720 if ( $subname =~ /\D/ ) { # subroutine name
2721 # Qualify it to the current package unless it's
2722 # already qualified.
69893cff
RGS
2723 $subname = $package . "::" . $subname
2724 unless $subname =~ /::/;
e22ea7cc 2725
69893cff
RGS
2726 # find_sub will return "file:line_number" corresponding
2727 # to where the subroutine is defined; we call find_sub,
e22ea7cc 2728 # break up the return value, and assign it in one
69893cff 2729 # operation.
e22ea7cc 2730 ( $file, $i ) = ( find_sub($subname) =~ /^(.*):(.*)$/ );
69893cff
RGS
2731
2732 # Force the line number to be numeric.
e22ea7cc 2733 $i += 0;
69893cff
RGS
2734
2735 # If we got a line number, we found the sub.
e22ea7cc
RF
2736 if ($i) {
2737
69893cff
RGS
2738 # Switch all the debugger's internals around so
2739 # we're actually working with that file.
e22ea7cc
RF
2740 $filename = $file;
2741 *dbline = $main::{ '_<' . $filename };
2742
69893cff 2743 # Mark that there's a breakpoint in this file.
e22ea7cc
RF
2744 $had_breakpoints{$filename} |= 1;
2745
69893cff
RGS
2746 # Scan forward to the first executable line
2747 # after the 'sub whatever' line.
e22ea7cc
RF
2748 $max = $#dbline;
2749 ++$i while $dbline[$i] == 0 && $i < $max;
2750 } ## end if ($i)
69893cff
RGS
2751
2752 # We didn't find a sub by that name.
e22ea7cc
RF
2753 else {
2754 print $OUT "Subroutine $subname not found.\n";
2755 next CMD;
2756 }
2757 } ## end if ($subname =~ /\D/)
69893cff
RGS
2758
2759 # At this point, either the subname was all digits (an
2760 # absolute line-break request) or we've scanned through
2761 # the code following the definition of the sub, looking
2762 # for an executable, which we may or may not have found.
2763 #
2764 # If $i (which we set $subname from) is non-zero, we
e22ea7cc
RF
2765 # got a request to break at some line somewhere. On
2766 # one hand, if there wasn't any real subroutine name
2767 # involved, this will be a request to break in the current
2768 # file at the specified line, so we have to check to make
69893cff
RGS
2769 # sure that the line specified really is breakable.
2770 #
2771 # On the other hand, if there was a subname supplied, the
3c4b39be 2772 # preceding block has moved us to the proper file and
69893cff
RGS
2773 # location within that file, and then scanned forward
2774 # looking for the next executable line. We have to make
2775 # sure that one was found.
2776 #
2777 # On the gripping hand, we can't do anything unless the
2778 # current value of $i points to a valid breakable line.
2779 # Check that.
e22ea7cc
RF
2780 if ($i) {
2781
69893cff 2782 # Breakable?
e22ea7cc
RF
2783 if ( $dbline[$i] == 0 ) {
2784 print $OUT "Line $i not breakable.\n";
2785 next CMD;
2786 }
2787
69893cff 2788 # Yes. Set up the one-time-break sigil.
e22ea7cc
RF
2789 $dbline{$i} =~ s/($|\0)/;9$1/; # add one-time-only b.p.
2790 } ## end if ($i)
69893cff
RGS
2791
2792 # Turn off stack tracing from here up.
e22ea7cc
RF
2793 for ( $i = 0 ; $i <= $stack_depth ; ) {
2794 $stack[ $i++ ] &= ~1;
2795 }
2796 last CMD;
2797 };
69893cff
RGS
2798
2799=head4 C<r> - return from a subroutine
2800
2801For C<r> to work properly, the debugger has to stop execution again
2802immediately after the return is executed. This is done by forcing
2803single-stepping to be on in the call level above the current one. If
2804we are printing return values when a C<r> is executed, set C<$doret>
2805appropriately, and force us out of the command loop.
2806
2807=cut
2808
2809 # r - return from the current subroutine.
e22ea7cc
RF
2810 $cmd =~ /^r$/ && do {
2811
69893cff 2812 # Can't do anythign if the program's over.
e22ea7cc
RF
2813 end_report(), next CMD if $finished and $level <= 1;
2814
69893cff 2815 # Turn on stack trace.
e22ea7cc
RF
2816 $stack[$stack_depth] |= 1;
2817
69893cff 2818 # Print return value unless the stack is empty.
e22ea7cc
RF
2819 $doret = $option{PrintRet} ? $stack_depth - 1 : -2;
2820 last CMD;
2821 };
69893cff 2822
69893cff
RGS
2823=head4 C<T> - stack trace
2824
2825Just calls C<DB::print_trace>.
2826
2827=cut
2828
e22ea7cc
RF
2829 $cmd =~ /^T$/ && do {
2830 print_trace( $OUT, 1 ); # skip DB
2831 next CMD;
2832 };
69893cff
RGS
2833
2834=head4 C<w> - List window around current line.
2835
2836Just calls C<DB::cmd_w>.
2837
2838=cut
2839
e22ea7cc 2840 $cmd =~ /^w\b\s*(.*)/s && do { &cmd_w( 'w', $1 ); next CMD; };
69893cff
RGS
2841
2842=head4 C<W> - watch-expression processing.
2843
2844Just calls C<DB::cmd_W>.
2845
2846=cut
2847
e22ea7cc 2848 $cmd =~ /^W\b\s*(.*)/s && do { &cmd_W( 'W', $1 ); next CMD; };
69893cff
RGS
2849
2850=head4 C</> - search forward for a string in the source
2851
2852We take the argument and treat it as a pattern. If it turns out to be a
2853bad one, we return the error we got from trying to C<eval> it and exit.
2854If not, we create some code to do the search and C<eval> it so it can't
2855mess us up.
2856
2857=cut
2858
e22ea7cc 2859 $cmd =~ /^\/(.*)$/ && do {
69893cff
RGS
2860
2861 # The pattern as a string.
e22ea7cc 2862 $inpat = $1;
69893cff
RGS
2863
2864 # Remove the final slash.
e22ea7cc 2865 $inpat =~ s:([^\\])/$:$1:;
69893cff
RGS
2866
2867 # If the pattern isn't null ...
e22ea7cc 2868 if ( $inpat ne "" ) {
69893cff
RGS
2869
2870 # Turn of warn and die procesing for a bit.
e22ea7cc
RF
2871 local $SIG{__DIE__};
2872 local $SIG{__WARN__};
69893cff
RGS
2873
2874 # Create the pattern.
e22ea7cc
RF
2875 eval '$inpat =~ m' . "\a$inpat\a";
2876 if ( $@ ne "" ) {
2877
69893cff 2878 # Oops. Bad pattern. No biscuit.
e22ea7cc 2879 # Print the eval error and go back for more
69893cff 2880 # commands.
e22ea7cc
RF
2881 print $OUT "$@";
2882 next CMD;
2883 }
2884 $pat = $inpat;
2885 } ## end if ($inpat ne "")
69893cff
RGS
2886
2887 # Set up to stop on wrap-around.
e22ea7cc 2888 $end = $start;
69893cff
RGS
2889
2890 # Don't move off the current line.
e22ea7cc 2891 $incr = -1;
69893cff
RGS
2892
2893 # Done in eval so nothing breaks if the pattern
2894 # does something weird.
e22ea7cc
RF
2895 eval '
2896 for (;;) {
69893cff 2897 # Move ahead one line.
e22ea7cc 2898 ++$start;
69893cff
RGS
2899
2900 # Wrap if we pass the last line.
e22ea7cc 2901 $start = 1 if ($start > $max);
69893cff
RGS
2902
2903 # Stop if we have gotten back to this line again,
e22ea7cc 2904 last if ($start == $end);
69893cff
RGS
2905
2906 # A hit! (Note, though, that we are doing
2907 # case-insensitive matching. Maybe a qr//
2908 # expression would be better, so the user could
2909 # do case-sensitive matching if desired.
e22ea7cc
RF
2910 if ($dbline[$start] =~ m' . "\a$pat\a" . 'i) {
2911 if ($slave_editor) {
69893cff 2912 # Handle proper escaping in the slave.
e22ea7cc
RF
2913 print $OUT "\032\032$filename:$start:0\n";
2914 }
2915 else {
69893cff 2916 # Just print the line normally.
e22ea7cc
RF
2917 print $OUT "$start:\t",$dbline[$start],"\n";
2918 }
69893cff 2919 # And quit since we found something.
e22ea7cc
RF
2920 last;
2921 }
2922 } ';
2923
69893cff 2924 # If we wrapped, there never was a match.
e22ea7cc
RF
2925 print $OUT "/$pat/: not found\n" if ( $start == $end );
2926 next CMD;
2927 };
69893cff
RGS
2928
2929=head4 C<?> - search backward for a string in the source
2930
2931Same as for C</>, except the loop runs backwards.
2932
2933=cut
2934
2935 # ? - backward pattern search.
e22ea7cc 2936 $cmd =~ /^\?(.*)$/ && do {
69893cff
RGS
2937
2938 # Get the pattern, remove trailing question mark.
e22ea7cc
RF
2939 $inpat = $1;
2940 $inpat =~ s:([^\\])\?$:$1:;
69893cff
RGS
2941
2942 # If we've got one ...
e22ea7cc 2943 if ( $inpat ne "" ) {
69893cff
RGS
2944
2945 # Turn off die & warn handlers.
e22ea7cc
RF
2946 local $SIG{__DIE__};
2947 local $SIG{__WARN__};
2948 eval '$inpat =~ m' . "\a$inpat\a";
2949
2950 if ( $@ ne "" ) {
2951
69893cff 2952 # Ouch. Not good. Print the error.
e22ea7cc
RF
2953 print $OUT $@;
2954 next CMD;
2955 }
2956 $pat = $inpat;
69893cff 2957 } ## end if ($inpat ne "")
e22ea7cc 2958
69893cff 2959 # Where we are now is where to stop after wraparound.
e22ea7cc 2960 $end = $start;
69893cff
RGS
2961
2962 # Don't move away from this line.
e22ea7cc 2963 $incr = -1;
69893cff
RGS
2964
2965 # Search inside the eval to prevent pattern badness
2966 # from killing us.
e22ea7cc
RF
2967 eval '
2968 for (;;) {
69893cff 2969 # Back up a line.
e22ea7cc 2970 --$start;
69893cff
RGS
2971
2972 # Wrap if we pass the first line.
e22ea7cc
RF
2973
2974 $start = $max if ($start <= 0);
69893cff
RGS
2975
2976 # Quit if we get back where we started,
e22ea7cc 2977 last if ($start == $end);
69893cff
RGS
2978
2979 # Match?
e22ea7cc
RF
2980 if ($dbline[$start] =~ m' . "\a$pat\a" . 'i) {
2981 if ($slave_editor) {
69893cff 2982 # Yep, follow slave editor requirements.
e22ea7cc
RF
2983 print $OUT "\032\032$filename:$start:0\n";
2984 }
2985 else {
69893cff 2986 # Yep, just print normally.
e22ea7cc
RF
2987 print $OUT "$start:\t",$dbline[$start],"\n";
2988 }
69893cff
RGS
2989
2990 # Found, so done.
e22ea7cc
RF
2991 last;
2992 }
2993 } ';
2994
2995 # Say we failed if the loop never found anything,
2996 print $OUT "?$pat?: not found\n" if ( $start == $end );
2997 next CMD;
2998 };
69893cff
RGS
2999
3000=head4 C<$rc> - Recall command
3001
3002Manages the commands in C<@hist> (which is created if C<Term::ReadLine> reports
3003that the terminal supports history). It find the the command required, puts it
3004into C<$cmd>, and redoes the loop to execute it.
3005
3006=cut
3007
e22ea7cc
RF
3008 # $rc - recall command.
3009 $cmd =~ /^$rc+\s*(-)?(\d+)?$/ && do {
69893cff
RGS
3010
3011 # No arguments, take one thing off history.
e22ea7cc 3012 pop(@hist) if length($cmd) > 1;
69893cff 3013
e22ea7cc 3014 # Relative (- found)?
69893cff 3015 # Y - index back from most recent (by 1 if bare minus)
e22ea7cc 3016 # N - go to that particular command slot or the last
69893cff 3017 # thing if nothing following.
e22ea7cc 3018 $i = $1 ? ( $#hist - ( $2 || 1 ) ) : ( $2 || $#hist );
69893cff
RGS
3019
3020 # Pick out the command desired.
e22ea7cc 3021 $cmd = $hist[$i];
69893cff
RGS
3022
3023 # Print the command to be executed and restart the loop
3024 # with that command in the buffer.
e22ea7cc
RF
3025 print $OUT $cmd, "\n";
3026 redo CMD;
3027 };
69893cff
RGS
3028
3029=head4 C<$sh$sh> - C<system()> command
3030
3031Calls the C<DB::system()> to handle the command. This keeps the C<STDIN> and
3032C<STDOUT> from getting messed up.
3033
3034=cut
3035
3036 # $sh$sh - run a shell command (if it's all ASCII).
3037 # Can't run shell commands with Unicode in the debugger, hmm.
e22ea7cc
RF
3038 $cmd =~ /^$sh$sh\s*([\x00-\xff]*)/ && do {
3039
69893cff 3040 # System it.
e22ea7cc
RF
3041 &system($1);
3042 next CMD;
3043 };
69893cff
RGS
3044
3045=head4 C<$rc I<pattern> $rc> - Search command history
3046
3047Another command to manipulate C<@hist>: this one searches it with a pattern.
be9a9b1d 3048If a command is found, it is placed in C<$cmd> and executed via C<redo>.
69893cff
RGS
3049
3050=cut
3051
e22ea7cc
RF
3052 # $rc pattern $rc - find a command in the history.
3053 $cmd =~ /^$rc([^$rc].*)$/ && do {
3054
69893cff 3055 # Create the pattern to use.
e22ea7cc 3056 $pat = "^$1";
69893cff
RGS
3057
3058 # Toss off last entry if length is >1 (and it always is).
e22ea7cc 3059 pop(@hist) if length($cmd) > 1;
69893cff
RGS
3060
3061 # Look backward through the history.
e22ea7cc
RF
3062 for ( $i = $#hist ; $i ; --$i ) {
3063
69893cff 3064 # Stop if we find it.
e22ea7cc
RF
3065 last if $hist[$i] =~ /$pat/;
3066 }
3067
3068 if ( !$i ) {
69893cff 3069
69893cff 3070 # Never found it.
e22ea7cc
RF
3071 print $OUT "No such command!\n\n";
3072 next CMD;
3073 }
69893cff
RGS
3074
3075 # Found it. Put it in the buffer, print it, and process it.
e22ea7cc
RF
3076 $cmd = $hist[$i];
3077 print $OUT $cmd, "\n";
3078 redo CMD;
3079 };
69893cff
RGS
3080
3081=head4 C<$sh> - Invoke a shell
3082
3083Uses C<DB::system> to invoke a shell.
3084
3085=cut
3086
3087 # $sh - start a shell.
e22ea7cc
RF
3088 $cmd =~ /^$sh$/ && do {
3089
69893cff
RGS
3090 # Run the user's shell. If none defined, run Bourne.
3091 # We resume execution when the shell terminates.
e22ea7cc
RF
3092 &system( $ENV{SHELL} || "/bin/sh" );
3093 next CMD;
3094 };
69893cff
RGS
3095
3096=head4 C<$sh I<command>> - Force execution of a command in a shell
3097
3098Like the above, but the command is passed to the shell. Again, we use
3099C<DB::system> to avoid problems with C<STDIN> and C<STDOUT>.
3100
3101=cut
3102
3103 # $sh command - start a shell and run a command in it.
e22ea7cc
RF
3104 $cmd =~ /^$sh\s*([\x00-\xff]*)/ && do {
3105
3106 # XXX: using csh or tcsh destroys sigint retvals!
3107 #&system($1); # use this instead
69893cff
RGS
3108
3109 # use the user's shell, or Bourne if none defined.
e22ea7cc
RF
3110 &system( $ENV{SHELL} || "/bin/sh", "-c", $1 );
3111 next CMD;
3112 };
69893cff
RGS
3113
3114=head4 C<H> - display commands in history
3115
3116Prints the contents of C<@hist> (if any).
3117
3118=cut
3119
7fddc82f
RF
3120 $cmd =~ /^H\b\s*\*/ && do {
3121 @hist = @truehist = ();
3122 print $OUT "History cleansed\n";
3123 next CMD;
3124 };
e22ea7cc
RF
3125
3126 $cmd =~ /^H\b\s*(-(\d+))?/ && do {
3127
3128 # Anything other than negative numbers is ignored by
69893cff 3129 # the (incorrect) pattern, so this test does nothing.
e22ea7cc 3130 $end = $2 ? ( $#hist - $2 ) : 0;
69893cff
RGS
3131
3132 # Set to the minimum if less than zero.
e22ea7cc 3133 $hist = 0 if $hist < 0;
69893cff 3134
e22ea7cc 3135 # Start at the end of the array.
69893cff
RGS
3136 # Stay in while we're still above the ending value.
3137 # Tick back by one each time around the loop.
e22ea7cc 3138 for ( $i = $#hist ; $i > $end ; $i-- ) {
69893cff
RGS
3139
3140 # Print the command unless it has no arguments.
e22ea7cc
RF
3141 print $OUT "$i: ", $hist[$i], "\n"
3142 unless $hist[$i] =~ /^.?$/;
3143 }
3144 next CMD;
3145 };
69893cff
RGS
3146
3147=head4 C<man, doc, perldoc> - look up documentation
3148
3149Just calls C<runman()> to print the appropriate document.
3150
3151=cut
3152
e22ea7cc
RF
3153 # man, perldoc, doc - show manual pages.
3154 $cmd =~ /^(?:man|(?:perl)?doc)\b(?:\s+([^(]*))?$/ && do {
3155 runman($1);
3156 next CMD;
3157 };
69893cff
RGS
3158
3159=head4 C<p> - print
3160
3161Builds a C<print EXPR> expression in the C<$cmd>; this will get executed at
3162the bottom of the loop.
3163
3164=cut
3165
3166 # p - print (no args): print $_.
e22ea7cc 3167 $cmd =~ s/^p$/print {\$DB::OUT} \$_/;
69893cff
RGS
3168
3169 # p - print the given expression.
e22ea7cc 3170 $cmd =~ s/^p\b/print {\$DB::OUT} /;
69893cff
RGS
3171
3172=head4 C<=> - define command alias
3173
3174Manipulates C<%alias> to add or list command aliases.
3175
3176=cut
3177
e22ea7cc
RF
3178 # = - set up a command alias.
3179 $cmd =~ s/^=\s*// && do {
3180 my @keys;
3181 if ( length $cmd == 0 ) {
3182
69893cff 3183 # No args, get current aliases.
e22ea7cc
RF
3184 @keys = sort keys %alias;
3185 }
3186 elsif ( my ( $k, $v ) = ( $cmd =~ /^(\S+)\s+(\S.*)/ ) ) {
3187
69893cff
RGS
3188 # Creating a new alias. $k is alias name, $v is
3189 # alias value.
3190
e22ea7cc
RF
3191 # can't use $_ or kill //g state
3192 for my $x ( $k, $v ) {
3193
3194 # Escape "alarm" characters.
3195 $x =~ s/\a/\\a/g;
3196 }
69893cff
RGS
3197
3198 # Substitute key for value, using alarm chars
e22ea7cc 3199 # as separators (which is why we escaped them in
69893cff 3200 # the command).
e22ea7cc 3201 $alias{$k} = "s\a$k\a$v\a";
69893cff
RGS
3202
3203 # Turn off standard warn and die behavior.
e22ea7cc
RF
3204 local $SIG{__DIE__};
3205 local $SIG{__WARN__};
69893cff
RGS
3206
3207 # Is it valid Perl?
e22ea7cc
RF
3208 unless ( eval "sub { s\a$k\a$v\a }; 1" ) {
3209
69893cff 3210 # Nope. Bad alias. Say so and get out.
e22ea7cc
RF
3211 print $OUT "Can't alias $k to $v: $@\n";
3212 delete $alias{$k};
3213 next CMD;
3214 }
3215
69893cff 3216 # We'll only list the new one.
e22ea7cc 3217 @keys = ($k);
69893cff
RGS
3218 } ## end elsif (my ($k, $v) = ($cmd...
3219
3220 # The argument is the alias to list.
e22ea7cc
RF
3221 else {
3222 @keys = ($cmd);
3223 }
69893cff
RGS
3224
3225 # List aliases.
e22ea7cc
RF
3226 for my $k (@keys) {
3227
69893cff
RGS
3228 # Messy metaquoting: Trim the substiution code off.
3229 # We use control-G as the delimiter because it's not
3230 # likely to appear in the alias.
e22ea7cc
RF
3231 if ( ( my $v = $alias{$k} ) =~ s\as\a$k\a(.*)\a$\a1\a ) {
3232
69893cff 3233 # Print the alias.
e22ea7cc
RF
3234 print $OUT "$k\t= $1\n";
3235 }
3236 elsif ( defined $alias{$k} ) {
3237
69893cff 3238 # Couldn't trim it off; just print the alias code.
e22ea7cc
RF
3239 print $OUT "$k\t$alias{$k}\n";
3240 }
3241 else {
3242
69893cff 3243 # No such, dude.
e22ea7cc
RF
3244 print "No alias for $k\n";
3245 }
69893cff 3246 } ## end for my $k (@keys)
e22ea7cc
RF
3247 next CMD;
3248 };
69893cff
RGS
3249
3250=head4 C<source> - read commands from a file.
3251
3252Opens a lexical filehandle and stacks it on C<@cmdfhs>; C<DB::readline> will
3253pick it up.
3254
3255=cut
3256
e22ea7cc
RF
3257 # source - read commands from a file (or pipe!) and execute.
3258 $cmd =~ /^source\s+(.*\S)/ && do {
3259 if ( open my $fh, $1 ) {
3260
69893cff 3261 # Opened OK; stick it in the list of file handles.
e22ea7cc
RF
3262 push @cmdfhs, $fh;
3263 }
3264 else {
3265
3266 # Couldn't open it.
3267 &warn("Can't execute `$1': $!\n");
3268 }
3269 next CMD;
3270 };
69893cff
RGS
3271
3272=head4 C<save> - send current history to a file
3273
3274Takes the complete history, (not the shrunken version you see with C<H>),
3275and saves it to the given filename, so it can be replayed using C<source>.
3276
3277Note that all C<^(save|source)>'s are commented out with a view to minimise recursion.
3278
3279=cut
3280
3281 # save source - write commands to a file for later use
3282 $cmd =~ /^save\s*(.*)$/ && do {
e22ea7cc
RF
3283 my $file = $1 || '.perl5dbrc'; # default?
3284 if ( open my $fh, "> $file" ) {
3285
3286 # chomp to remove extraneous newlines from source'd files
3287 chomp( my @truelist =
3288 map { m/^\s*(save|source)/ ? "#$_" : $_ }
3289 @truehist );
3290 print $fh join( "\n", @truelist );
69893cff 3291 print "commands saved in $file\n";
e22ea7cc
RF
3292 }
3293 else {
69893cff
RGS
3294 &warn("Can't save debugger commands in '$1': $!\n");
3295 }
3296 next CMD;
3297 };
3298
7fddc82f
RF
3299=head4 C<R> - restart
3300
3301Restart the debugger session.
3302
3303=head4 C<rerun> - rerun the current session
3304
3305Return to any given position in the B<true>-history list
3306
3307=cut
3308
3309 # R - restart execution.
3310 # rerun - controlled restart execution.
3311 $cmd =~ /^(R|rerun\s*(.*))$/ && do {
3312 my @args = ($1 eq 'R' ? restart() : rerun($2));
3313
ca28b541
AP
3314 # Close all non-system fds for a clean restart. A more
3315 # correct method would be to close all fds that were not
3316 # open when the process started, but this seems to be
3317 # hard. See "debugger 'R'estart and open database
3318 # connections" on p5p.
3319
47d3bbda 3320 my $max_fd = 1024; # default if POSIX can't be loaded
ca28b541
AP
3321 if (eval { require POSIX }) {
3322 $max_fd = POSIX::sysconf(POSIX::_SC_OPEN_MAX());
3323 }
3324
3325 if (defined $max_fd) {
3326 foreach ($^F+1 .. $max_fd-1) {
3327 next unless open FD_TO_CLOSE, "<&=$_";
3328 close(FD_TO_CLOSE);
3329 }
3330 }
3331
7fddc82f
RF
3332 # And run Perl again. We use exec() to keep the
3333 # PID stable (and that way $ini_pids is still valid).
3334 exec(@args) || print $OUT "exec failed: $!\n";
3335
3336 last CMD;
3337 };
3338
69893cff
RGS
3339=head4 C<|, ||> - pipe output through the pager.
3340
be9a9b1d 3341For C<|>, we save C<OUT> (the debugger's output filehandle) and C<STDOUT>
69893cff
RGS
3342(the program's standard output). For C<||>, we only save C<OUT>. We open a
3343pipe to the pager (restoring the output filehandles if this fails). If this
3344is the C<|> command, we also set up a C<SIGPIPE> handler which will simply
3345set C<$signal>, sending us back into the debugger.
3346
3347We then trim off the pipe symbols and C<redo> the command loop at the
3348C<PIPE> label, causing us to evaluate the command in C<$cmd> without
3349reading another.
3350
3351=cut
3352
3353 # || - run command in the pager, with output to DB::OUT.
e22ea7cc
RF
3354 $cmd =~ /^\|\|?\s*[^|]/ && do {
3355 if ( $pager =~ /^\|/ ) {
3356
69893cff 3357 # Default pager is into a pipe. Redirect I/O.
e22ea7cc
RF
3358 open( SAVEOUT, ">&STDOUT" )
3359 || &warn("Can't save STDOUT");
3360 open( STDOUT, ">&OUT" )
3361 || &warn("Can't redirect STDOUT");
69893cff 3362 } ## end if ($pager =~ /^\|/)
e22ea7cc
RF
3363 else {
3364
69893cff 3365 # Not into a pipe. STDOUT is safe.
e22ea7cc
RF
3366 open( SAVEOUT, ">&OUT" ) || &warn("Can't save DB::OUT");
3367 }
69893cff
RGS
3368
3369 # Fix up environment to record we have less if so.
e22ea7cc
RF
3370 fix_less();
3371
3372 unless ( $piped = open( OUT, $pager ) ) {
69893cff 3373
69893cff 3374 # Couldn't open pipe to pager.
e22ea7cc
RF
3375 &warn("Can't pipe output to `$pager'");
3376 if ( $pager =~ /^\|/ ) {
3377
69893cff 3378 # Redirect I/O back again.
e22ea7cc
RF
3379 open( OUT, ">&STDOUT" ) # XXX: lost message
3380 || &warn("Can't restore DB::OUT");
3381 open( STDOUT, ">&SAVEOUT" )
3382 || &warn("Can't restore STDOUT");
3383 close(SAVEOUT);
69893cff 3384 } ## end if ($pager =~ /^\|/)
e22ea7cc
RF
3385 else {
3386
69893cff 3387 # Redirect I/O. STDOUT already safe.
e22ea7cc
RF
3388 open( OUT, ">&STDOUT" ) # XXX: lost message
3389 || &warn("Can't restore DB::OUT");
3390 }
3391 next CMD;
69893cff
RGS
3392 } ## end unless ($piped = open(OUT,...
3393
3394 # Set up broken-pipe handler if necessary.
e22ea7cc
RF
3395 $SIG{PIPE} = \&DB::catch
3396 if $pager =~ /^\|/
3397 && ( "" eq $SIG{PIPE} || "DEFAULT" eq $SIG{PIPE} );
69893cff
RGS
3398
3399 # Save current filehandle, unbuffer out, and put it back.
e22ea7cc
RF
3400 $selected = select(OUT);
3401 $| = 1;
69893cff
RGS
3402
3403 # Don't put it back if pager was a pipe.
e22ea7cc 3404 select($selected), $selected = "" unless $cmd =~ /^\|\|/;
69893cff
RGS
3405
3406 # Trim off the pipe symbols and run the command now.
e22ea7cc
RF
3407 $cmd =~ s/^\|+\s*//;
3408 redo PIPE;
3409 };
69893cff
RGS
3410
3411=head3 END OF COMMAND PARSING
3412
3413Anything left in C<$cmd> at this point is a Perl expression that we want to
3414evaluate. We'll always evaluate in the user's context, and fully qualify
3415any variables we might want to address in the C<DB> package.
3416
3417=cut
3418
3419 # t - turn trace on.
e22ea7cc 3420 $cmd =~ s/^t\s/\$DB::trace |= 1;\n/;
69893cff
RGS
3421
3422 # s - single-step. Remember the last command was 's'.
e22ea7cc 3423 $cmd =~ s/^s\s/\$DB::single = 1;\n/ && do { $laststep = 's' };
69893cff
RGS
3424
3425 # n - single-step, but not into subs. Remember last command
e22ea7cc
RF
3426 # was 'n'.
3427 $cmd =~ s/^n\s/\$DB::single = 2;\n/ && do { $laststep = 'n' };
69893cff 3428
e22ea7cc 3429 } # PIPE:
69893cff 3430
e22ea7cc 3431 # Make sure the flag that says "the debugger's running" is
69893cff 3432 # still on, to make sure we get control again.
e22ea7cc 3433 $evalarg = "\$^D = \$^D | \$DB::db_stop;\n$cmd";
69893cff
RGS
3434
3435 # Run *our* eval that executes in the caller's context.
e22ea7cc 3436 &eval;
69893cff
RGS
3437
3438 # Turn off the one-time-dump stuff now.
e22ea7cc
RF
3439 if ($onetimeDump) {
3440 $onetimeDump = undef;
69893cff 3441 $onetimedumpDepth = undef;
e22ea7cc
RF
3442 }
3443 elsif ( $term_pid == $$ ) {
c7e68384
IZ
3444 eval { # May run under miniperl, when not available...
3445 STDOUT->flush();
3446 STDERR->flush();
3447 };
e22ea7cc 3448
69893cff 3449 # XXX If this is the master pid, print a newline.
e22ea7cc
RF
3450 print $OUT "\n";
3451 }
3452 } ## end while (($term || &setterm...
69893cff
RGS
3453
3454=head3 POST-COMMAND PROCESSING
3455
3456After each command, we check to see if the command output was piped anywhere.
3457If so, we go through the necessary code to unhook the pipe and go back to
3458our standard filehandles for input and output.
3459
3460=cut
3461
e22ea7cc 3462 continue { # CMD:
69893cff
RGS
3463
3464 # At the end of every command:
e22ea7cc
RF
3465 if ($piped) {
3466
69893cff 3467 # Unhook the pipe mechanism now.
e22ea7cc
RF
3468 if ( $pager =~ /^\|/ ) {
3469
69893cff 3470 # No error from the child.
e22ea7cc 3471 $? = 0;
69893cff 3472
e22ea7cc
RF
3473 # we cannot warn here: the handle is missing --tchrist
3474 close(OUT) || print SAVEOUT "\nCan't close DB::OUT\n";
69893cff 3475
e22ea7cc 3476 # most of the $? crud was coping with broken cshisms
69893cff 3477 # $? is explicitly set to 0, so this never runs.
e22ea7cc
RF
3478 if ($?) {
3479 print SAVEOUT "Pager `$pager' failed: ";
3480 if ( $? == -1 ) {
3481 print SAVEOUT "shell returned -1\n";
3482 }
3483 elsif ( $? >> 8 ) {
3484 print SAVEOUT ( $? & 127 )
3485 ? " (SIG#" . ( $? & 127 ) . ")"
3486 : "", ( $? & 128 ) ? " -- core dumped" : "", "\n";
3487 }
3488 else {
3489 print SAVEOUT "status ", ( $? >> 8 ), "\n";
3490 }
69893cff
RGS
3491 } ## end if ($?)
3492
e22ea7cc 3493 # Reopen filehandle for our output (if we can) and
69893cff 3494 # restore STDOUT (if we can).
e22ea7cc
RF
3495 open( OUT, ">&STDOUT" ) || &warn("Can't restore DB::OUT");
3496 open( STDOUT, ">&SAVEOUT" )
3497 || &warn("Can't restore STDOUT");
69893cff
RGS
3498
3499 # Turn off pipe exception handler if necessary.
e22ea7cc 3500 $SIG{PIPE} = "DEFAULT" if $SIG{PIPE} eq \&DB::catch;
69893cff 3501
e22ea7cc
RF
3502 # Will stop ignoring SIGPIPE if done like nohup(1)
3503 # does SIGINT but Perl doesn't give us a choice.
69893cff 3504 } ## end if ($pager =~ /^\|/)
e22ea7cc
RF
3505 else {
3506
69893cff 3507 # Non-piped "pager". Just restore STDOUT.
e22ea7cc
RF
3508 open( OUT, ">&SAVEOUT" ) || &warn("Can't restore DB::OUT");
3509 }
69893cff
RGS
3510
3511 # Close filehandle pager was using, restore the normal one
3512 # if necessary,
3513 close(SAVEOUT);
e22ea7cc 3514 select($selected), $selected = "" unless $selected eq "";
69893cff
RGS
3515
3516 # No pipes now.
e22ea7cc 3517 $piped = "";
69893cff 3518 } ## end if ($piped)
e22ea7cc 3519 } # CMD:
69893cff
RGS
3520
3521=head3 COMMAND LOOP TERMINATION
3522
3523When commands have finished executing, we come here. If the user closed the
3524input filehandle, we turn on C<$fall_off_end> to emulate a C<q> command. We
3525evaluate any post-prompt items. We restore C<$@>, C<$!>, C<$^E>, C<$,>, C<$/>,
3526C<$\>, and C<$^W>, and return a null list as expected by the Perl interpreter.
3527The interpreter will then execute the next line and then return control to us
3528again.
3529
3530=cut
3531
3532 # No more commands? Quit.
e22ea7cc 3533 $fall_off_end = 1 unless defined $cmd; # Emulate `q' on EOF
69893cff
RGS
3534
3535 # Evaluate post-prompt commands.
e22ea7cc
RF
3536 foreach $evalarg (@$post) {
3537 &eval;
3538 }
3539 } # if ($single || $signal)
69893cff
RGS
3540
3541 # Put the user's globals back where you found them.
e22ea7cc 3542 ( $@, $!, $^E, $,, $/, $\, $^W ) = @saved;
69893cff
RGS
3543 ();
3544} ## end sub DB
3545
3546# The following code may be executed now:
3547# BEGIN {warn 4}
3548
3549=head2 sub
3550
3551C<sub> is called whenever a subroutine call happens in the program being
3552debugged. The variable C<$DB::sub> contains the name of the subroutine
3553being called.
3554
3555The core function of this subroutine is to actually call the sub in the proper
3556context, capturing its output. This of course causes C<DB::DB> to get called
3557again, repeating until the subroutine ends and returns control to C<DB::sub>
3558again. Once control returns, C<DB::sub> figures out whether or not to dump the
3559return value, and returns its captured copy of the return value as its own
3560return value. The value then feeds back into the program being debugged as if
3561C<DB::sub> hadn't been there at all.
3562
3563C<sub> does all the work of printing the subroutine entry and exit messages
3564enabled by setting C<$frame>. It notes what sub the autoloader got called for,
3565and also prints the return value if needed (for the C<r> command and if
3566the 16 bit is set in C<$frame>).
3567
3568It also tracks the subroutine call depth by saving the current setting of
3569C<$single> in the C<@stack> package global; if this exceeds the value in
3570C<$deep>, C<sub> automatically turns on printing of the current depth by
be9a9b1d 3571setting the C<4> bit in C<$single>. In any case, it keeps the current setting
69893cff
RGS
3572of stop/don't stop on entry to subs set as it currently is set.
3573
3574=head3 C<caller()> support
3575
3576If C<caller()> is called from the package C<DB>, it provides some
3577additional data, in the following order:
3578
3579=over 4
3580
3581=item * C<$package>
3582
3583The package name the sub was in
3584
3585=item * C<$filename>
3586
3587The filename it was defined in
3588
3589=item * C<$line>
3590
3591The line number it was defined on
3592
3593=item * C<$subroutine>
3594
be9a9b1d 3595The subroutine name; C<(eval)> if an C<eval>().
69893cff
RGS
3596
3597=item * C<$hasargs>
3598
35991 if it has arguments, 0 if not
3600
3601=item * C<$wantarray>
3602
36031 if array context, 0 if scalar context
3604
3605=item * C<$evaltext>
3606
3607The C<eval>() text, if any (undefined for C<eval BLOCK>)
3608
3609=item * C<$is_require>
3610
3611frame was created by a C<use> or C<require> statement
3612
3613=item * C<$hints>
3614
3615pragma information; subject to change between versions
3616
3617=item * C<$bitmask>
3618
be9a9b1d 3619pragma information; subject to change between versions
69893cff
RGS
3620
3621=item * C<@DB::args>
3622
3623arguments with which the subroutine was invoked
3624
3625=back
3626
3627=cut
d338d6fe 3628
d12a4851 3629sub sub {
69893cff 3630
2cbb2ee1
RGS
3631 # lock ourselves under threads
3632 lock($DBGR);
3633
69893cff
RGS
3634 # Whether or not the autoloader was running, a scalar to put the
3635 # sub's return value in (if needed), and an array to put the sub's
3636 # return value in (if needed).
e22ea7cc 3637 my ( $al, $ret, @ret ) = "";
2cbb2ee1
RGS
3638 if ($sub =~ /^threads::new$/ && $ENV{PERL5DB_THREADED}) {
3639 print "creating new thread\n";
3640 }
69893cff 3641
c81c05fc 3642 # If the last ten characters are '::AUTOLOAD', note we've traced
69893cff 3643 # into AUTOLOAD for $sub.
e22ea7cc 3644 if ( length($sub) > 10 && substr( $sub, -10, 10 ) eq '::AUTOLOAD' ) {
c81c05fc 3645 $al = " for $$sub" if defined $$sub;
d12a4851 3646 }
69893cff
RGS
3647
3648 # We stack the stack pointer and then increment it to protect us
3649 # from a situation that might unwind a whole bunch of call frames
3650 # at once. Localizing the stack pointer means that it will automatically
3651 # unwind the same amount when multiple stack frames are unwound.
e22ea7cc 3652 local $stack_depth = $stack_depth + 1; # Protect from non-local exits
69893cff
RGS
3653
3654 # Expand @stack.
d12a4851 3655 $#stack = $stack_depth;
69893cff
RGS
3656
3657 # Save current single-step setting.
d12a4851 3658 $stack[-1] = $single;
69893cff 3659
e22ea7cc 3660 # Turn off all flags except single-stepping.
d12a4851 3661 $single &= 1;
69893cff
RGS
3662
3663 # If we've gotten really deeply recursed, turn on the flag that will
3664 # make us stop with the 'deep recursion' message.
d12a4851 3665 $single |= 4 if $stack_depth == $deep;
69893cff
RGS
3666
3667 # If frame messages are on ...
3668 (
3669 $frame & 4 # Extended frame entry message
e22ea7cc
RF
3670 ? (
3671 print_lineinfo( ' ' x ( $stack_depth - 1 ), "in " ),
69893cff 3672
e22ea7cc 3673 # Why -1? But it works! :-(
69893cff
RGS
3674 # Because print_trace will call add 1 to it and then call
3675 # dump_trace; this results in our skipping -1+1 = 0 stack frames
3676 # in dump_trace.
e22ea7cc
RF
3677 print_trace( $LINEINFO, -1, 1, 1, "$sub$al" )
3678 )
3679 : print_lineinfo( ' ' x ( $stack_depth - 1 ), "entering $sub$al\n" )
3680
69893cff 3681 # standard frame entry message
e22ea7cc
RF
3682 )
3683 if $frame;
69893cff
RGS
3684
3685 # Determine the sub's return type,and capture approppriately.
d12a4851 3686 if (wantarray) {
e22ea7cc 3687
69893cff
RGS
3688 # Called in array context. call sub and capture output.
3689 # DB::DB will recursively get control again if appropriate; we'll come
3690 # back here when the sub is finished.
584420f0 3691 @ret = &$sub;
69893cff
RGS
3692
3693 # Pop the single-step value back off the stack.
e22ea7cc 3694 $single |= $stack[ $stack_depth-- ];
69893cff
RGS
3695
3696 # Check for exit trace messages...
e22ea7cc
RF
3697 (
3698 $frame & 4 # Extended exit message
3699 ? (
3700 print_lineinfo( ' ' x $stack_depth, "out " ),
3701 print_trace( $LINEINFO, -1, 1, 1, "$sub$al" )
3702