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Fix Attribute::Handlers to cope with proxy constant subroutines.
[perl5.git] / lib / perl5db.pl
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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
224If false, a dummy ReadLine is used, so you can debug
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
240=back
241
242=head3 SAMPLE RCFILE
243
244 &parse_options("NonStop=1 LineInfo=db.out");
245 sub afterinit { $trace = 1; }
246
247The script will run without human intervention, putting trace
248information into C<db.out>. (If you interrupt it, you had better
be9a9b1d 249reset C<LineInfo> to something I<interactive>!)
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250
251=head1 INTERNALS DESCRIPTION
252
253=head2 DEBUGGER INTERFACE VARIABLES
254
255Perl supplies the values for C<%sub>. It effectively inserts
be9a9b1d 256a C<&DB::DB();> in front of each place that can have a
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257breakpoint. At each subroutine call, it calls C<&DB::sub> with
258C<$DB::sub> set to the called subroutine. It also inserts a C<BEGIN
259{require 'perl5db.pl'}> before the first line.
260
261After each C<require>d file is compiled, but before it is executed, a
262call to C<&DB::postponed($main::{'_<'.$filename})> is done. C<$filename>
263is the expanded name of the C<require>d file (as found via C<%INC>).
264
265=head3 IMPORTANT INTERNAL VARIABLES
266
267=head4 C<$CreateTTY>
268
269Used to control when the debugger will attempt to acquire another TTY to be
270used for input.
271
272=over
273
274=item * 1 - on C<fork()>
275
276=item * 2 - debugger is started inside debugger
277
278=item * 4 - on startup
279
280=back
281
282=head4 C<$doret>
283
284The value -2 indicates that no return value should be printed.
285Any other positive value causes C<DB::sub> to print return values.
286
287=head4 C<$evalarg>
288
289The item to be eval'ed by C<DB::eval>. Used to prevent messing with the current
290contents of C<@_> when C<DB::eval> is called.
291
292=head4 C<$frame>
293
294Determines what messages (if any) will get printed when a subroutine (or eval)
295is entered or exited.
296
297=over 4
298
299=item * 0 - No enter/exit messages
300
be9a9b1d 301=item * 1 - Print I<entering> messages on subroutine entry
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302
303=item * 2 - Adds exit messages on subroutine exit. If no other flag is on, acts like 1+2.
304
be9a9b1d 305=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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306
307=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.
308
309=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.
310
311=back
312
be9a9b1d 313To get everything, use C<$frame=30> (or C<o f=30> as a debugger command).
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314The debugger internally juggles the value of C<$frame> during execution to
315protect external modules that the debugger uses from getting traced.
316
317=head4 C<$level>
318
319Tracks current debugger nesting level. Used to figure out how many
320C<E<lt>E<gt>> pairs to surround the line number with when the debugger
321outputs a prompt. Also used to help determine if the program has finished
322during command parsing.
323
324=head4 C<$onetimeDump>
325
326Controls what (if anything) C<DB::eval()> will print after evaluating an
327expression.
328
329=over 4
330
331=item * C<undef> - don't print anything
332
333=item * C<dump> - use C<dumpvar.pl> to display the value returned
334
335=item * C<methods> - print the methods callable on the first item returned
336
337=back
338
339=head4 C<$onetimeDumpDepth>
340
be9a9b1d 341Controls how far down C<dumpvar.pl> will go before printing C<...> while
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342dumping a structure. Numeric. If C<undef>, print all levels.
343
344=head4 C<$signal>
345
346Used to track whether or not an C<INT> signal has been detected. C<DB::DB()>,
347which is called before every statement, checks this and puts the user into
348command mode if it finds C<$signal> set to a true value.
349
350=head4 C<$single>
351
352Controls behavior during single-stepping. Stacked in C<@stack> on entry to
353each subroutine; popped again at the end of each subroutine.
354
355=over 4
356
357=item * 0 - run continuously.
358
be9a9b1d 359=item * 1 - single-step, go into subs. The C<s> command.
69893cff 360
be9a9b1d 361=item * 2 - single-step, don't go into subs. The C<n> command.
69893cff 362
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363=item * 4 - print current sub depth (turned on to force this when C<too much
364recursion> occurs.
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365
366=back
367
368=head4 C<$trace>
369
370Controls the output of trace information.
371
372=over 4
373
374=item * 1 - The C<t> command was entered to turn on tracing (every line executed is printed)
375
376=item * 2 - watch expressions are active
377
378=item * 4 - user defined a C<watchfunction()> in C<afterinit()>
379
380=back
381
382=head4 C<$slave_editor>
383
3841 if C<LINEINFO> was directed to a pipe; 0 otherwise.
385
386=head4 C<@cmdfhs>
387
388Stack of filehandles that C<DB::readline()> will read commands from.
389Manipulated by the debugger's C<source> command and C<DB::readline()> itself.
390
391=head4 C<@dbline>
392
393Local alias to the magical line array, C<@{$main::{'_<'.$filename}}> ,
394supplied by the Perl interpreter to the debugger. Contains the source.
395
396=head4 C<@old_watch>
397
398Previous values of watch expressions. First set when the expression is
399entered; reset whenever the watch expression changes.
400
401=head4 C<@saved>
402
403Saves important globals (C<$@>, C<$!>, C<$^E>, C<$,>, C<$/>, C<$\>, C<$^W>)
404so that the debugger can substitute safe values while it's running, and
405restore them when it returns control.
406
407=head4 C<@stack>
408
409Saves the current value of C<$single> on entry to a subroutine.
410Manipulated by the C<c> command to turn off tracing in all subs above the
411current one.
412
413=head4 C<@to_watch>
414
415The 'watch' expressions: to be evaluated before each line is executed.
416
417=head4 C<@typeahead>
418
419The typeahead buffer, used by C<DB::readline>.
420
421=head4 C<%alias>
422
423Command aliases. Stored as character strings to be substituted for a command
424entered.
425
426=head4 C<%break_on_load>
427
428Keys are file names, values are 1 (break when this file is loaded) or undef
429(don't break when it is loaded).
430
431=head4 C<%dbline>
432
be9a9b1d 433Keys are line numbers, values are C<condition\0action>. If used in numeric
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434context, values are 0 if not breakable, 1 if breakable, no matter what is
435in the actual hash entry.
436
437=head4 C<%had_breakpoints>
438
439Keys are file names; values are bitfields:
440
441=over 4
442
443=item * 1 - file has a breakpoint in it.
444
445=item * 2 - file has an action in it.
446
447=back
448
449A zero or undefined value means this file has neither.
450
451=head4 C<%option>
452
453Stores the debugger options. These are character string values.
454
455=head4 C<%postponed>
456
457Saves breakpoints for code that hasn't been compiled yet.
458Keys are subroutine names, values are:
459
460=over 4
461
be9a9b1d 462=item * C<compile> - break when this sub is compiled
69893cff 463
be9a9b1d 464=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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465
466=back
467
468=head4 C<%postponed_file>
469
470This hash keeps track of breakpoints that need to be set for files that have
471not yet been compiled. Keys are filenames; values are references to hashes.
472Each of these hashes is keyed by line number, and its values are breakpoint
be9a9b1d 473definitions (C<condition\0action>).
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474
475=head1 DEBUGGER INITIALIZATION
476
477The debugger's initialization actually jumps all over the place inside this
478package. This is because there are several BEGIN blocks (which of course
479execute immediately) spread through the code. Why is that?
480
481The debugger needs to be able to change some things and set some things up
482before the debugger code is compiled; most notably, the C<$deep> variable that
483C<DB::sub> uses to tell when a program has recursed deeply. In addition, the
484debugger has to turn off warnings while the debugger code is compiled, but then
485restore them to their original setting before the program being debugged begins
486executing.
487
488The first C<BEGIN> block simply turns off warnings by saving the current
489setting of C<$^W> and then setting it to zero. The second one initializes
490the debugger variables that are needed before the debugger begins executing.
491The third one puts C<$^X> back to its former value.
492
493We'll detail the second C<BEGIN> block later; just remember that if you need
494to initialize something before the debugger starts really executing, that's
495where it has to go.
496
497=cut
498
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499package DB;
500
c7e68384 501BEGIN {eval 'use IO::Handle'}; # Needed for flush only? breaks under miniperl
9eba6a4e 502
54d04a52 503# Debugger for Perl 5.00x; perl5db.pl patch level:
2cbb2ee1 504$VERSION = 1.28;
69893cff 505
e22ea7cc 506$header = "perl5db.pl version $VERSION";
d338d6fe 507
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508=head1 DEBUGGER ROUTINES
509
510=head2 C<DB::eval()>
511
512This function replaces straight C<eval()> inside the debugger; it simplifies
513the process of evaluating code in the user's context.
514
515The code to be evaluated is passed via the package global variable
516C<$DB::evalarg>; this is done to avoid fiddling with the contents of C<@_>.
517
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518Before we do the C<eval()>, we preserve the current settings of C<$trace>,
519C<$single>, C<$^D> and C<$usercontext>. The latter contains the
520preserved values of C<$@>, C<$!>, C<$^E>, C<$,>, C<$/>, C<$\>, C<$^W> and the
521user's current package, grabbed when C<DB::DB> got control. This causes the
522proper context to be used when the eval is actually done. Afterward, we
523restore C<$trace>, C<$single>, and C<$^D>.
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524
525Next we need to handle C<$@> without getting confused. We save C<$@> in a
526local lexical, localize C<$saved[0]> (which is where C<save()> will put
527C<$@>), and then call C<save()> to capture C<$@>, C<$!>, C<$^E>, C<$,>,
528C<$/>, C<$\>, and C<$^W>) and set C<$,>, C<$/>, C<$\>, and C<$^W> to values
529considered sane by the debugger. If there was an C<eval()> error, we print
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530it on the debugger's output. If C<$onetimedump> is defined, we call
531C<dumpit> if it's set to 'dump', or C<methods> if it's set to
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532'methods'. Setting it to something else causes the debugger to do the eval
533but not print the result - handy if you want to do something else with it
534(the "watch expressions" code does this to get the value of the watch
535expression but not show it unless it matters).
536
537In any case, we then return the list of output from C<eval> to the caller,
538and unwinding restores the former version of C<$@> in C<@saved> as well
539(the localization of C<$saved[0]> goes away at the end of this scope).
540
541=head3 Parameters and variables influencing execution of DB::eval()
542
543C<DB::eval> isn't parameterized in the standard way; this is to keep the
544debugger's calls to C<DB::eval()> from mucking with C<@_>, among other things.
545The variables listed below influence C<DB::eval()>'s execution directly.
546
547=over 4
548
549=item C<$evalarg> - the thing to actually be eval'ed
550
be9a9b1d 551=item C<$trace> - Current state of execution tracing
69893cff 552
be9a9b1d 553=item C<$single> - Current state of single-stepping
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554
555=item C<$onetimeDump> - what is to be displayed after the evaluation
556
557=item C<$onetimeDumpDepth> - how deep C<dumpit()> should go when dumping results
558
559=back
560
561The following variables are altered by C<DB::eval()> during its execution. They
562are "stacked" via C<local()>, enabling recursive calls to C<DB::eval()>.
563
564=over 4
565
566=item C<@res> - used to capture output from actual C<eval>.
567
568=item C<$otrace> - saved value of C<$trace>.
569
570=item C<$osingle> - saved value of C<$single>.
571
572=item C<$od> - saved value of C<$^D>.
573
574=item C<$saved[0]> - saved value of C<$@>.
575
576=item $\ - for output of C<$@> if there is an evaluation error.
577
578=back
579
580=head3 The problem of lexicals
581
582The context of C<DB::eval()> presents us with some problems. Obviously,
583we want to be 'sandboxed' away from the debugger's internals when we do
584the eval, but we need some way to control how punctuation variables and
585debugger globals are used.
586
587We can't use local, because the code inside C<DB::eval> can see localized
588variables; and we can't use C<my> either for the same reason. The code
589in this routine compromises and uses C<my>.
590
591After this routine is over, we don't have user code executing in the debugger's
592context, so we can use C<my> freely.
593
594=cut
595
596############################################## Begin lexical danger zone
597
598# 'my' variables used here could leak into (that is, be visible in)
599# the context that the code being evaluated is executing in. This means that
600# the code could modify the debugger's variables.
601#
602# Fiddling with the debugger's context could be Bad. We insulate things as
603# much as we can.
604
c1051fcf 605sub eval {
69893cff 606
c1051fcf 607 # 'my' would make it visible from user code
e22ea7cc 608 # but so does local! --tchrist
69893cff 609 # Remember: this localizes @DB::res, not @main::res.
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610 local @res;
611 {
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612
613 # Try to keep the user code from messing with us. Save these so that
614 # even if the eval'ed code changes them, we can put them back again.
615 # Needed because the user could refer directly to the debugger's
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616 # package globals (and any 'my' variables in this containing scope)
617 # inside the eval(), and we want to try to stay safe.
e22ea7cc 618 local $otrace = $trace;
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619 local $osingle = $single;
620 local $od = $^D;
621
622 # Untaint the incoming eval() argument.
623 { ($evalarg) = $evalarg =~ /(.*)/s; }
624
e22ea7cc 625 # $usercontext built in DB::DB near the comment
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626 # "set up the context for DB::eval ..."
627 # Evaluate and save any results.
e22ea7cc 628 @res = eval "$usercontext $evalarg;\n"; # '\n' for nice recursive debug
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629
630 # Restore those old values.
631 $trace = $otrace;
632 $single = $osingle;
633 $^D = $od;
c1051fcf 634 }
69893cff
RGS
635
636 # Save the current value of $@, and preserve it in the debugger's copy
637 # of the saved precious globals.
c1051fcf 638 my $at = $@;
69893cff
RGS
639
640 # Since we're only saving $@, we only have to localize the array element
641 # that it will be stored in.
e22ea7cc 642 local $saved[0]; # Preserve the old value of $@
c1051fcf 643 eval { &DB::save };
69893cff
RGS
644
645 # Now see whether we need to report an error back to the user.
c1051fcf 646 if ($at) {
69893cff
RGS
647 local $\ = '';
648 print $OUT $at;
649 }
650
651 # Display as required by the caller. $onetimeDump and $onetimedumpDepth
652 # are package globals.
653 elsif ($onetimeDump) {
e22ea7cc
RF
654 if ( $onetimeDump eq 'dump' ) {
655 local $option{dumpDepth} = $onetimedumpDepth
656 if defined $onetimedumpDepth;
657 dumpit( $OUT, \@res );
658 }
659 elsif ( $onetimeDump eq 'methods' ) {
660 methods( $res[0] );
661 }
69893cff 662 } ## end elsif ($onetimeDump)
c1051fcf 663 @res;
69893cff
RGS
664} ## end sub eval
665
666############################################## End lexical danger zone
c1051fcf 667
e22ea7cc
RF
668# After this point it is safe to introduce lexicals.
669# The code being debugged will be executing in its own context, and
69893cff 670# can't see the inside of the debugger.
d338d6fe 671#
e22ea7cc 672# However, one should not overdo it: leave as much control from outside as
69893cff
RGS
673# possible. If you make something a lexical, it's not going to be addressable
674# from outside the debugger even if you know its name.
675
d338d6fe
PP
676# This file is automatically included if you do perl -d.
677# It's probably not useful to include this yourself.
678#
e22ea7cc 679# Before venturing further into these twisty passages, it is
2f7e9187
MS
680# wise to read the perldebguts man page or risk the ire of dragons.
681#
69893cff
RGS
682# (It should be noted that perldebguts will tell you a lot about
683# the underlying mechanics of how the debugger interfaces into the
684# Perl interpreter, but not a lot about the debugger itself. The new
685# comments in this code try to address this problem.)
686
d338d6fe 687# Note that no subroutine call is possible until &DB::sub is defined
36477c24 688# (for subroutines defined outside of the package DB). In fact the same is
d338d6fe 689# true if $deep is not defined.
055fd3a9
GS
690
691# Enhanced by ilya@math.ohio-state.edu (Ilya Zakharevich)
055fd3a9
GS
692
693# modified Perl debugger, to be run from Emacs in perldb-mode
694# Ray Lischner (uunet!mntgfx!lisch) as of 5 Nov 1990
695# Johan Vromans -- upgrade to 4.0 pl 10
696# Ilya Zakharevich -- patches after 5.001 (and some before ;-)
697
69893cff
RGS
698# (We have made efforts to clarify the comments in the change log
699# in other places; some of them may seem somewhat obscure as they
700# were originally written, and explaining them away from the code
701# in question seems conterproductive.. -JM)
702
703########################################################################
704# Changes: 0.94
705# + A lot of things changed after 0.94. First of all, core now informs
706# debugger about entry into XSUBs, overloaded operators, tied operations,
707# BEGIN and END. Handy with `O f=2'.
708# + This can make debugger a little bit too verbose, please be patient
709# and report your problems promptly.
710# + Now the option frame has 3 values: 0,1,2. XXX Document!
711# + Note that if DESTROY returns a reference to the object (or object),
712# the deletion of data may be postponed until the next function call,
713# due to the need to examine the return value.
714#
715# Changes: 0.95
716# + `v' command shows versions.
717#
e22ea7cc 718# Changes: 0.96
69893cff
RGS
719# + `v' command shows version of readline.
720# primitive completion works (dynamic variables, subs for `b' and `l',
721# options). Can `p %var'
722# + Better help (`h <' now works). New commands <<, >>, {, {{.
723# {dump|print}_trace() coded (to be able to do it from <<cmd).
724# + `c sub' documented.
725# + At last enough magic combined to stop after the end of debuggee.
726# + !! should work now (thanks to Emacs bracket matching an extra
727# `]' in a regexp is caught).
728# + `L', `D' and `A' span files now (as documented).
729# + Breakpoints in `require'd code are possible (used in `R').
730# + Some additional words on internal work of debugger.
731# + `b load filename' implemented.
732# + `b postpone subr' implemented.
733# + now only `q' exits debugger (overwritable on $inhibit_exit).
734# + When restarting debugger breakpoints/actions persist.
e22ea7cc 735# + Buglet: When restarting debugger only one breakpoint/action per
69893cff
RGS
736# autoloaded function persists.
737#
36477c24 738# Changes: 0.97: NonStop will not stop in at_exit().
69893cff
RGS
739# + Option AutoTrace implemented.
740# + Trace printed differently if frames are printed too.
741# + new `inhibitExit' option.
742# + printing of a very long statement interruptible.
1d06cb2d 743# Changes: 0.98: New command `m' for printing possible methods
69893cff
RGS
744# + 'l -' is a synonym for `-'.
745# + Cosmetic bugs in printing stack trace.
746# + `frame' & 8 to print "expanded args" in stack trace.
747# + Can list/break in imported subs.
748# + new `maxTraceLen' option.
749# + frame & 4 and frame & 8 granted.
750# + new command `m'
751# + nonstoppable lines do not have `:' near the line number.
752# + `b compile subname' implemented.
753# + Will not use $` any more.
754# + `-' behaves sane now.
477ea2b1 755# Changes: 0.99: Completion for `f', `m'.
69893cff
RGS
756# + `m' will remove duplicate names instead of duplicate functions.
757# + `b load' strips trailing whitespace.
758# completion ignores leading `|'; takes into account current package
759# when completing a subroutine name (same for `l').
055fd3a9
GS
760# Changes: 1.07: Many fixed by tchrist 13-March-2000
761# BUG FIXES:
04e43a21 762# + Added bare minimal security checks on perldb rc files, plus
055fd3a9
GS
763# comments on what else is needed.
764# + Fixed the ornaments that made "|h" completely unusable.
765# They are not used in print_help if they will hurt. Strip pod
766# if we're paging to less.
767# + Fixed mis-formatting of help messages caused by ornaments
e22ea7cc
RF
768# to restore Larry's original formatting.
769# + Fixed many other formatting errors. The code is still suboptimal,
04e43a21 770# and needs a lot of work at restructuring. It's also misindented
055fd3a9
GS
771# in many places.
772# + Fixed bug where trying to look at an option like your pager
e22ea7cc 773# shows "1".
055fd3a9
GS
774# + Fixed some $? processing. Note: if you use csh or tcsh, you will
775# lose. You should consider shell escapes not using their shell,
776# or else not caring about detailed status. This should really be
777# unified into one place, too.
778# + Fixed bug where invisible trailing whitespace on commands hoses you,
04e43a21 779# tricking Perl into thinking you weren't calling a debugger command!
055fd3a9
GS
780# + Fixed bug where leading whitespace on commands hoses you. (One
781# suggests a leading semicolon or any other irrelevant non-whitespace
782# to indicate literal Perl code.)
783# + Fixed bugs that ate warnings due to wrong selected handle.
784# + Fixed a precedence bug on signal stuff.
785# + Fixed some unseemly wording.
786# + Fixed bug in help command trying to call perl method code.
787# + Fixed to call dumpvar from exception handler. SIGPIPE killed us.
788# ENHANCEMENTS:
789# + Added some comments. This code is still nasty spaghetti.
790# + Added message if you clear your pre/post command stacks which was
791# very easy to do if you just typed a bare >, <, or {. (A command
792# without an argument should *never* be a destructive action; this
793# API is fundamentally screwed up; likewise option setting, which
794# is equally buggered.)
795# + Added command stack dump on argument of "?" for >, <, or {.
796# + Added a semi-built-in doc viewer command that calls man with the
797# proper %Config::Config path (and thus gets caching, man -k, etc),
798# or else perldoc on obstreperous platforms.
799# + Added to and rearranged the help information.
800# + Detected apparent misuse of { ... } to declare a block; this used
801# to work but now is a command, and mysteriously gave no complaint.
04e43a21
DL
802#
803# Changes: 1.08: Apr 25, 2001 Jon Eveland <jweveland@yahoo.com>
804# BUG FIX:
805# + This patch to perl5db.pl cleans up formatting issues on the help
806# summary (h h) screen in the debugger. Mostly columnar alignment
807# issues, plus converted the printed text to use all spaces, since
808# tabs don't seem to help much here.
809#
810# Changes: 1.09: May 19, 2001 Ilya Zakharevich <ilya@math.ohio-state.edu>
69893cff
RGS
811# Minor bugs corrected;
812# + Support for auto-creation of new TTY window on startup, either
813# unconditionally, or if started as a kid of another debugger session;
814# + New `O'ption CreateTTY
815# I<CreateTTY> bits control attempts to create a new TTY on events:
e22ea7cc 816# 1: on fork()
69893cff
RGS
817# 2: debugger is started inside debugger
818# 4: on startup
819# + Code to auto-create a new TTY window on OS/2 (currently one
820# extra window per session - need named pipes to have more...);
821# + Simplified interface for custom createTTY functions (with a backward
822# compatibility hack); now returns the TTY name to use; return of ''
823# means that the function reset the I/O handles itself;
824# + Better message on the semantic of custom createTTY function;
825# + Convert the existing code to create a TTY into a custom createTTY
826# function;
827# + Consistent support for TTY names of the form "TTYin,TTYout";
828# + Switch line-tracing output too to the created TTY window;
829# + make `b fork' DWIM with CORE::GLOBAL::fork;
830# + High-level debugger API cmd_*():
04e43a21
DL
831# cmd_b_load($filenamepart) # b load filenamepart
832# cmd_b_line($lineno [, $cond]) # b lineno [cond]
833# cmd_b_sub($sub [, $cond]) # b sub [cond]
834# cmd_stop() # Control-C
492652be 835# cmd_d($lineno) # d lineno (B)
04e43a21
DL
836# The cmd_*() API returns FALSE on failure; in this case it outputs
837# the error message to the debugging output.
69893cff 838# + Low-level debugger API
04e43a21
DL
839# break_on_load($filename) # b load filename
840# @files = report_break_on_load() # List files with load-breakpoints
841# breakable_line_in_filename($name, $from [, $to])
842# # First breakable line in the
843# # range $from .. $to. $to defaults
e22ea7cc 844# # to $from, and may be less than
69893cff 845# # $to
04e43a21
DL
846# breakable_line($from [, $to]) # Same for the current file
847# break_on_filename_line($name, $lineno [, $cond])
e22ea7cc 848# # Set breakpoint,$cond defaults to
69893cff 849# # 1
04e43a21
DL
850# break_on_filename_line_range($name, $from, $to [, $cond])
851# # As above, on the first
852# # breakable line in range
853# break_on_line($lineno [, $cond]) # As above, in the current file
854# break_subroutine($sub [, $cond]) # break on the first breakable line
855# ($name, $from, $to) = subroutine_filename_lines($sub)
856# # The range of lines of the text
857# The low-level API returns TRUE on success, and die()s on failure.
858#
859# Changes: 1.10: May 23, 2001 Daniel Lewart <d-lewart@uiuc.edu>
860# BUG FIXES:
861# + Fixed warnings generated by "perl -dWe 42"
862# + Corrected spelling errors
863# + Squeezed Help (h) output into 80 columns
600d99fa
DL
864#
865# Changes: 1.11: May 24, 2001 David Dyck <dcd@tc.fluke.com>
866# + Made "x @INC" work like it used to
867#
868# Changes: 1.12: May 24, 2001 Daniel Lewart <d-lewart@uiuc.edu>
869# + Fixed warnings generated by "O" (Show debugger options)
870# + Fixed warnings generated by "p 42" (Print expression)
6f891d7d 871# Changes: 1.13: Jun 19, 2001 Scott.L.Miller@compaq.com
e22ea7cc 872# + Added windowSize option
2f7e9187
MS
873# Changes: 1.14: Oct 9, 2001 multiple
874# + Clean up after itself on VMS (Charles Lane in 12385)
875# + Adding "@ file" syntax (Peter Scott in 12014)
876# + Debug reloading selfloaded stuff (Ilya Zakharevich in 11457)
877# + $^S and other debugger fixes (Ilya Zakharevich in 11120)
878# + Forgot a my() declaration (Ilya Zakharevich in 11085)
879# Changes: 1.15: Nov 6, 2001 Michael G Schwern <schwern@pobox.com>
880# + Updated 1.14 change log
881# + Added *dbline explainatory comments
882# + Mentioning perldebguts man page
492652be 883# Changes: 1.16: Feb 15, 2002 Mark-Jason Dominus <mjd@plover.com>
69893cff 884# + $onetimeDump improvements
492652be
RF
885# Changes: 1.17: Feb 20, 2002 Richard Foley <richard.foley@rfi.net>
886# Moved some code to cmd_[.]()'s for clarity and ease of handling,
e22ea7cc
RF
887# rationalised the following commands and added cmd_wrapper() to
888# enable switching between old and frighteningly consistent new
492652be
RF
889# behaviours for diehards: 'o CommandSet=pre580' (sigh...)
890# a(add), A(del) # action expr (added del by line)
891# + b(add), B(del) # break [line] (was b,D)
e22ea7cc 892# + w(add), W(del) # watch expr (was W,W)
69893cff 893# # added del by expr
492652be
RF
894# + h(summary), h h(long) # help (hh) (was h h,h)
895# + m(methods), M(modules) # ... (was m,v)
896# + o(option) # lc (was O)
897# + v(view code), V(view Variables) # ... (was w,V)
aef14ef9
RF
898# Changes: 1.18: Mar 17, 2002 Richard Foley <richard.foley@rfi.net>
899# + fixed missing cmd_O bug
471505cc 900# Changes: 1.19: Mar 29, 2002 Spider Boardman
901# + Added missing local()s -- DB::DB is called recursively.
35408c4e
RF
902# Changes: 1.20: Feb 17, 2003 Richard Foley <richard.foley@rfi.net>
903# + pre'n'post commands no longer trashed with no args
904# + watch val joined out of eval()
69893cff
RGS
905# Changes: 1.21: Jun 04, 2003 Joe McMahon <mcmahon@ibiblio.org>
906# + Added comments and reformatted source. No bug fixes/enhancements.
907# + Includes cleanup by Robin Barker and Jarkko Hietaniemi.
908# Changes: 1.22 Jun 09, 2003 Alex Vandiver <alexmv@MIT.EDU>
909# + Flush stdout/stderr before the debugger prompt is printed.
910# Changes: 1.23: Dec 21, 2003 Dominique Quatravaux
de5e1a3d 911# + Fix a side-effect of bug #24674 in the perl debugger ("odd taint bug")
e219e2fb
RF
912# Changes: 1.24: Mar 03, 2004 Richard Foley <richard.foley@rfi.net>
913# + Added command to save all debugger commands for sourcing later.
3c4b39be 914# + Added command to display parent inheritance tree of given class.
e219e2fb 915# + Fixed minor newline in history bug.
e22ea7cc
RF
916# Changes: 1.25: Apr 17, 2004 Richard Foley <richard.foley@rfi.net>
917# + Fixed option bug (setting invalid options + not recognising valid short forms)
918# Changes: 1.26: Apr 22, 2004 Richard Foley <richard.foley@rfi.net>
919# + unfork the 5.8.x and 5.9.x debuggers.
920# + whitespace and assertions call cleanup across versions
921# + H * deletes (resets) history
922# + i now handles Class + blessed objects
7fddc82f
RF
923# Changes: 1.27: May 09, 2004 Richard Foley <richard.foley@rfi.net>
924# + updated pod page references - clunky.
925# + removed windowid restriction for forking into an xterm.
926# + more whitespace again.
927# + wrapped restart and enabled rerun [-n] (go back n steps) command.
2cbb2ee1
RGS
928# Changes: 1.28: Oct 12, 2004 Richard Foley <richard.foley@rfi.net>
929# + Added threads support (inc. e and E commands)
ee971a18 930####################################################################
d338d6fe 931
69893cff
RGS
932=head1 DEBUGGER INITIALIZATION
933
934The debugger starts up in phases.
935
936=head2 BASIC SETUP
937
938First, it initializes the environment it wants to run in: turning off
939warnings during its own compilation, defining variables which it will need
940to avoid warnings later, setting itself up to not exit when the program
941terminates, and defaulting to printing return values for the C<r> command.
942
943=cut
944
eda6e075 945# Needed for the statement after exec():
69893cff
RGS
946#
947# This BEGIN block is simply used to switch off warnings during debugger
948# compiliation. Probably it would be better practice to fix the warnings,
949# but this is how it's done at the moment.
eda6e075 950
e22ea7cc
RF
951BEGIN {
952 $ini_warn = $^W;
953 $^W = 0;
954} # Switch compilation warnings off until another BEGIN.
d12a4851
JH
955
956# test if assertions are supported and actived:
eda6e075 957BEGIN {
e22ea7cc
RF
958 $ini_assertion = eval "sub asserting_test : assertion {1}; 1";
959
d12a4851 960 # $ini_assertion = undef => assertions unsupported,
e22ea7cc 961 # " = 1 => assertions supported
d12a4851
JH
962 # print "\$ini_assertion=$ini_assertion\n";
963}
964
69893cff
RGS
965local ($^W) = 0; # Switch run-time warnings off during init.
966
2cbb2ee1
RGS
967=head2 THREADS SUPPORT
968
969If we are running under a threaded Perl, we require threads and threads::shared
970if the environment variable C<PERL5DB_THREADED> is set, to enable proper
971threaded debugger control. C<-dt> can also be used to set this.
972
973Each new thread will be announced and the debugger prompt will always inform
974you of each new thread created. It will also indicate the thread id in which
975we are currently running within the prompt like this:
976
977 [tid] DB<$i>
978
979Where C<[tid]> is an integer thread id and C<$i> is the familiar debugger
980command prompt. The prompt will show: C<[0]> when running under threads, but
981not actually in a thread. C<[tid]> is consistent with C<gdb> usage.
982
983While running under threads, when you set or delete a breakpoint (etc.), this
984will apply to all threads, not just the currently running one. When you are
985in a currently executing thread, you will stay there until it completes. With
986the current implementation it is not currently possible to hop from one thread
987to another.
988
989The C<e> and C<E> commands are currently fairly minimal - see C<h e> and C<h E>.
990
991Note that threading support was built into the debugger as of Perl version
992C<5.8.6> and debugger version C<1.2.8>.
993
994=cut
995
996BEGIN {
997 # ensure we can share our non-threaded variables or no-op
998 if ($ENV{PERL5DB_THREADED}) {
999 require threads;
1000 require threads::shared;
1001 import threads::shared qw(share);
1002 $DBGR;
1003 share(\$DBGR);
1004 lock($DBGR);
1005 print "Threads support enabled\n";
1006 } else {
1007 *lock = sub(*) {};
1008 *share = sub(*) {};
1009 }
1010}
1011
69893cff
RGS
1012# This would probably be better done with "use vars", but that wasn't around
1013# when this code was originally written. (Neither was "use strict".) And on
1014# the principle of not fiddling with something that was working, this was
1015# left alone.
1016warn( # Do not ;-)
2cbb2ee1 1017 # These variables control the execution of 'dumpvar.pl'.
69893cff
RGS
1018 $dumpvar::hashDepth,
1019 $dumpvar::arrayDepth,
1020 $dumpvar::dumpDBFiles,
1021 $dumpvar::dumpPackages,
1022 $dumpvar::quoteHighBit,
1023 $dumpvar::printUndef,
1024 $dumpvar::globPrint,
1025 $dumpvar::usageOnly,
1026
1027 # used to save @ARGV and extract any debugger-related flags.
1028 @ARGS,
1029
1030 # used to control die() reporting in diesignal()
1031 $Carp::CarpLevel,
1032
1033 # used to prevent multiple entries to diesignal()
1034 # (if for instance diesignal() itself dies)
1035 $panic,
1036
1037 # used to prevent the debugger from running nonstop
1038 # after a restart
1039 $second_time,
1040 )
1041 if 0;
d338d6fe 1042
2cbb2ee1
RGS
1043foreach my $k (keys (%INC)) {
1044 &share(\$main::{'_<'.$filename});
1045};
1046
54d04a52 1047# Command-line + PERLLIB:
69893cff 1048# Save the contents of @INC before they are modified elsewhere.
54d04a52
IZ
1049@ini_INC = @INC;
1050
69893cff
RGS
1051# This was an attempt to clear out the previous values of various
1052# trapped errors. Apparently it didn't help. XXX More info needed!
d338d6fe
PP
1053# $prevwarn = $prevdie = $prevbus = $prevsegv = ''; # Does not help?!
1054
69893cff
RGS
1055# We set these variables to safe values. We don't want to blindly turn
1056# off warnings, because other packages may still want them.
e22ea7cc
RF
1057$trace = $signal = $single = 0; # Uninitialized warning suppression
1058 # (local $^W cannot help - other packages!).
69893cff
RGS
1059
1060# Default to not exiting when program finishes; print the return
1061# value when the 'r' command is used to return from a subroutine.
55497cff 1062$inhibit_exit = $option{PrintRet} = 1;
d338d6fe 1063
69893cff
RGS
1064=head1 OPTION PROCESSING
1065
1066The debugger's options are actually spread out over the debugger itself and
1067C<dumpvar.pl>; some of these are variables to be set, while others are
1068subs to be called with a value. To try to make this a little easier to
1069manage, the debugger uses a few data structures to define what options
1070are legal and how they are to be processed.
1071
1072First, the C<@options> array defines the I<names> of all the options that
1073are to be accepted.
1074
1075=cut
1076
1077@options = qw(
e22ea7cc
RF
1078 CommandSet
1079 hashDepth arrayDepth dumpDepth
1080 DumpDBFiles DumpPackages DumpReused
1081 compactDump veryCompact quote
1082 HighBit undefPrint globPrint
1083 PrintRet UsageOnly frame
1084 AutoTrace TTY noTTY
1085 ReadLine NonStop LineInfo
1086 maxTraceLen recallCommand ShellBang
1087 pager tkRunning ornaments
1088 signalLevel warnLevel dieLevel
1089 inhibit_exit ImmediateStop bareStringify
1090 CreateTTY RemotePort windowSize
1091 DollarCaretP OnlyAssertions WarnAssertions
1092);
d12a4851
JH
1093
1094@RememberOnROptions = qw(DollarCaretP OnlyAssertions);
1095
69893cff
RGS
1096=pod
1097
1098Second, C<optionVars> lists the variables that each option uses to save its
1099state.
1100
1101=cut
1102
1103%optionVars = (
e22ea7cc
RF
1104 hashDepth => \$dumpvar::hashDepth,
1105 arrayDepth => \$dumpvar::arrayDepth,
1106 CommandSet => \$CommandSet,
1107 DumpDBFiles => \$dumpvar::dumpDBFiles,
1108 DumpPackages => \$dumpvar::dumpPackages,
1109 DumpReused => \$dumpvar::dumpReused,
1110 HighBit => \$dumpvar::quoteHighBit,
1111 undefPrint => \$dumpvar::printUndef,
1112 globPrint => \$dumpvar::globPrint,
1113 UsageOnly => \$dumpvar::usageOnly,
1114 CreateTTY => \$CreateTTY,
1115 bareStringify => \$dumpvar::bareStringify,
1116 frame => \$frame,
1117 AutoTrace => \$trace,
1118 inhibit_exit => \$inhibit_exit,
1119 maxTraceLen => \$maxtrace,
1120 ImmediateStop => \$ImmediateStop,
1121 RemotePort => \$remoteport,
1122 windowSize => \$window,
1123 WarnAssertions => \$warnassertions,
69893cff
RGS
1124);
1125
1126=pod
1127
1128Third, C<%optionAction> defines the subroutine to be called to process each
1129option.
1130
1131=cut
1132
1133%optionAction = (
1134 compactDump => \&dumpvar::compactDump,
1135 veryCompact => \&dumpvar::veryCompact,
1136 quote => \&dumpvar::quote,
1137 TTY => \&TTY,
1138 noTTY => \&noTTY,
1139 ReadLine => \&ReadLine,
1140 NonStop => \&NonStop,
1141 LineInfo => \&LineInfo,
1142 recallCommand => \&recallCommand,
1143 ShellBang => \&shellBang,
1144 pager => \&pager,
1145 signalLevel => \&signalLevel,
1146 warnLevel => \&warnLevel,
1147 dieLevel => \&dieLevel,
1148 tkRunning => \&tkRunning,
1149 ornaments => \&ornaments,
1150 RemotePort => \&RemotePort,
1151 DollarCaretP => \&DollarCaretP,
1152 OnlyAssertions=> \&OnlyAssertions,
d12a4851
JH
1153);
1154
69893cff
RGS
1155=pod
1156
1157Last, the C<%optionRequire> notes modules that must be C<require>d if an
1158option is used.
1159
1160=cut
d338d6fe 1161
69893cff
RGS
1162# Note that this list is not complete: several options not listed here
1163# actually require that dumpvar.pl be loaded for them to work, but are
1164# not in the table. A subsequent patch will correct this problem; for
1165# the moment, we're just recommenting, and we are NOT going to change
1166# function.
eda6e075 1167%optionRequire = (
69893cff
RGS
1168 compactDump => 'dumpvar.pl',
1169 veryCompact => 'dumpvar.pl',
1170 quote => 'dumpvar.pl',
e22ea7cc 1171);
69893cff
RGS
1172
1173=pod
1174
1175There are a number of initialization-related variables which can be set
1176by putting code to set them in a BEGIN block in the C<PERL5DB> environment
1177variable. These are:
1178
1179=over 4
1180
1181=item C<$rl> - readline control XXX needs more explanation
1182
1183=item C<$warnLevel> - whether or not debugger takes over warning handling
1184
1185=item C<$dieLevel> - whether or not debugger takes over die handling
1186
1187=item C<$signalLevel> - whether or not debugger takes over signal handling
1188
1189=item C<$pre> - preprompt actions (array reference)
1190
1191=item C<$post> - postprompt actions (array reference)
1192
1193=item C<$pretype>
1194
1195=item C<$CreateTTY> - whether or not to create a new TTY for this debugger
1196
1197=item C<$CommandSet> - which command set to use (defaults to new, documented set)
1198
1199=back
1200
1201=cut
d338d6fe
PP
1202
1203# These guys may be defined in $ENV{PERL5DB} :
69893cff
RGS
1204$rl = 1 unless defined $rl;
1205$warnLevel = 1 unless defined $warnLevel;
1206$dieLevel = 1 unless defined $dieLevel;
1207$signalLevel = 1 unless defined $signalLevel;
1208$pre = [] unless defined $pre;
1209$post = [] unless defined $post;
1210$pretype = [] unless defined $pretype;
1211$CreateTTY = 3 unless defined $CreateTTY;
1212$CommandSet = '580' unless defined $CommandSet;
1213
2cbb2ee1
RGS
1214share($rl);
1215share($warnLevel);
1216share($dieLevel);
1217share($signalLevel);
1218share($pre);
1219share($post);
1220share($pretype);
1221share($rl);
1222share($CreateTTY);
1223share($CommandSet);
1224
69893cff
RGS
1225=pod
1226
1227The default C<die>, C<warn>, and C<signal> handlers are set up.
1228
1229=cut
055fd3a9 1230
d338d6fe
PP
1231warnLevel($warnLevel);
1232dieLevel($dieLevel);
1233signalLevel($signalLevel);
055fd3a9 1234
69893cff
RGS
1235=pod
1236
1237The pager to be used is needed next. We try to get it from the
1238environment first. if it's not defined there, we try to find it in
1239the Perl C<Config.pm>. If it's not there, we default to C<more>. We
1240then call the C<pager()> function to save the pager name.
1241
1242=cut
1243
1244# This routine makes sure $pager is set up so that '|' can use it.
4865a36d 1245pager(
e22ea7cc 1246
69893cff 1247 # If PAGER is defined in the environment, use it.
e22ea7cc
RF
1248 defined $ENV{PAGER}
1249 ? $ENV{PAGER}
69893cff
RGS
1250
1251 # If not, see if Config.pm defines it.
e22ea7cc
RF
1252 : eval { require Config }
1253 && defined $Config::Config{pager}
1254 ? $Config::Config{pager}
69893cff
RGS
1255
1256 # If not, fall back to 'more'.
e22ea7cc
RF
1257 : 'more'
1258 )
1259 unless defined $pager;
69893cff
RGS
1260
1261=pod
1262
1263We set up the command to be used to access the man pages, the command
be9a9b1d
AT
1264recall character (C<!> unless otherwise defined) and the shell escape
1265character (C<!> unless otherwise defined). Yes, these do conflict, and
69893cff
RGS
1266neither works in the debugger at the moment.
1267
1268=cut
1269
055fd3a9 1270setman();
69893cff
RGS
1271
1272# Set up defaults for command recall and shell escape (note:
1273# these currently don't work in linemode debugging).
d338d6fe 1274&recallCommand("!") unless defined $prc;
69893cff
RGS
1275&shellBang("!") unless defined $psh;
1276
1277=pod
1278
1279We then set up the gigantic string containing the debugger help.
1280We also set the limit on the number of arguments we'll display during a
1281trace.
1282
1283=cut
1284
04e43a21 1285sethelp();
69893cff
RGS
1286
1287# If we didn't get a default for the length of eval/stack trace args,
1288# set it here.
1d06cb2d 1289$maxtrace = 400 unless defined $maxtrace;
69893cff
RGS
1290
1291=head2 SETTING UP THE DEBUGGER GREETING
1292
be9a9b1d 1293The debugger I<greeting> helps to inform the user how many debuggers are
69893cff
RGS
1294running, and whether the current debugger is the primary or a child.
1295
1296If we are the primary, we just hang onto our pid so we'll have it when
1297or if we start a child debugger. If we are a child, we'll set things up
1298so we'll have a unique greeting and so the parent will give us our own
1299TTY later.
1300
1301We save the current contents of the C<PERLDB_PIDS> environment variable
1302because we mess around with it. We'll also need to hang onto it because
1303we'll need it if we restart.
1304
1305Child debuggers make a label out of the current PID structure recorded in
1306PERLDB_PIDS plus the new PID. They also mark themselves as not having a TTY
1307yet so the parent will give them one later via C<resetterm()>.
1308
1309=cut
1310
e22ea7cc 1311# Save the current contents of the environment; we're about to
69893cff 1312# much with it. We'll need this if we have to restart.
f1583d8f 1313$ini_pids = $ENV{PERLDB_PIDS};
69893cff 1314
e22ea7cc
RF
1315if ( defined $ENV{PERLDB_PIDS} ) {
1316
69893cff 1317 # We're a child. Make us a label out of the current PID structure
e22ea7cc 1318 # recorded in PERLDB_PIDS plus our (new) PID. Mark us as not having
69893cff 1319 # a term yet so the parent will give us one later via resetterm().
55f4245e
JM
1320
1321 my $env_pids = $ENV{PERLDB_PIDS};
1322 $pids = "[$env_pids]";
1323
1324 # Unless we are on OpenVMS, all programs under the DCL shell run under
1325 # the same PID.
1326
1327 if (($^O eq 'VMS') && ($env_pids =~ /\b$$\b/)) {
1328 $term_pid = $$;
1329 }
1330 else {
1331 $ENV{PERLDB_PIDS} .= "->$$";
1332 $term_pid = -1;
1333 }
1334
69893cff
RGS
1335} ## end if (defined $ENV{PERLDB_PIDS...
1336else {
e22ea7cc
RF
1337
1338 # We're the parent PID. Initialize PERLDB_PID in case we end up with a
69893cff
RGS
1339 # child debugger, and mark us as the parent, so we'll know to set up
1340 # more TTY's is we have to.
1341 $ENV{PERLDB_PIDS} = "$$";
e22ea7cc
RF
1342 $pids = "{pid=$$}";
1343 $term_pid = $$;
f1583d8f 1344}
69893cff 1345
f1583d8f 1346$pidprompt = '';
69893cff
RGS
1347
1348# Sets up $emacs as a synonym for $slave_editor.
1349*emacs = $slave_editor if $slave_editor; # May be used in afterinit()...
1350
1351=head2 READING THE RC FILE
1352
1353The debugger will read a file of initialization options if supplied. If
1354running interactively, this is C<.perldb>; if not, it's C<perldb.ini>.
1355
1356=cut
1357
1358# As noted, this test really doesn't check accurately that the debugger
1359# is running at a terminal or not.
d338d6fe 1360
e22ea7cc
RF
1361if ( -e "/dev/tty" ) { # this is the wrong metric!
1362 $rcfile = ".perldb";
1363}
69893cff
RGS
1364else {
1365 $rcfile = "perldb.ini";
d338d6fe
PP
1366}
1367
69893cff
RGS
1368=pod
1369
1370The debugger does a safety test of the file to be read. It must be owned
1371either by the current user or root, and must only be writable by the owner.
1372
1373=cut
1374
1375# This wraps a safety test around "do" to read and evaluate the init file.
1376#
055fd3a9
GS
1377# This isn't really safe, because there's a race
1378# between checking and opening. The solution is to
1379# open and fstat the handle, but then you have to read and
1380# eval the contents. But then the silly thing gets
69893cff
RGS
1381# your lexical scope, which is unfortunate at best.
1382sub safe_do {
055fd3a9
GS
1383 my $file = shift;
1384
1385 # Just exactly what part of the word "CORE::" don't you understand?
69893cff
RGS
1386 local $SIG{__WARN__};
1387 local $SIG{__DIE__};
055fd3a9 1388
e22ea7cc 1389 unless ( is_safe_file($file) ) {
69893cff 1390 CORE::warn <<EO_GRIPE;
055fd3a9
GS
1391perldb: Must not source insecure rcfile $file.
1392 You or the superuser must be the owner, and it must not
69893cff 1393 be writable by anyone but its owner.
055fd3a9 1394EO_GRIPE
69893cff
RGS
1395 return;
1396 } ## end unless (is_safe_file($file...
055fd3a9
GS
1397
1398 do $file;
1399 CORE::warn("perldb: couldn't parse $file: $@") if $@;
69893cff 1400} ## end sub safe_do
055fd3a9 1401
69893cff
RGS
1402# This is the safety test itself.
1403#
055fd3a9
GS
1404# Verifies that owner is either real user or superuser and that no
1405# one but owner may write to it. This function is of limited use
1406# when called on a path instead of upon a handle, because there are
1407# no guarantees that filename (by dirent) whose file (by ino) is
e22ea7cc 1408# eventually accessed is the same as the one tested.
055fd3a9
GS
1409# Assumes that the file's existence is not in doubt.
1410sub is_safe_file {
1411 my $path = shift;
69893cff 1412 stat($path) || return; # mysteriously vaporized
e22ea7cc 1413 my ( $dev, $ino, $mode, $nlink, $uid, $gid ) = stat(_);
055fd3a9
GS
1414
1415 return 0 if $uid != 0 && $uid != $<;
1416 return 0 if $mode & 022;
1417 return 1;
69893cff 1418} ## end sub is_safe_file
055fd3a9 1419
69893cff 1420# If the rcfile (whichever one we decided was the right one to read)
e22ea7cc
RF
1421# exists, we safely do it.
1422if ( -f $rcfile ) {
055fd3a9 1423 safe_do("./$rcfile");
69893cff 1424}
e22ea7cc 1425
69893cff 1426# If there isn't one here, try the user's home directory.
e22ea7cc 1427elsif ( defined $ENV{HOME} && -f "$ENV{HOME}/$rcfile" ) {
055fd3a9
GS
1428 safe_do("$ENV{HOME}/$rcfile");
1429}
e22ea7cc 1430
69893cff 1431# Else try the login directory.
e22ea7cc 1432elsif ( defined $ENV{LOGDIR} && -f "$ENV{LOGDIR}/$rcfile" ) {
055fd3a9 1433 safe_do("$ENV{LOGDIR}/$rcfile");
d338d6fe
PP
1434}
1435
69893cff 1436# If the PERLDB_OPTS variable has options in it, parse those out next.
e22ea7cc
RF
1437if ( defined $ENV{PERLDB_OPTS} ) {
1438 parse_options( $ENV{PERLDB_OPTS} );
d338d6fe
PP
1439}
1440
69893cff
RGS
1441=pod
1442
1443The last thing we do during initialization is determine which subroutine is
1444to be used to obtain a new terminal when a new debugger is started. Right now,
1445the debugger only handles X Windows and OS/2.
1446
1447=cut
1448
1449# Set up the get_fork_TTY subroutine to be aliased to the proper routine.
1450# Works if you're running an xterm or xterm-like window, or you're on
1451# OS/2. This may need some expansion: for instance, this doesn't handle
e22ea7cc
RF
1452# OS X Terminal windows.
1453
1454if (
1455 not defined &get_fork_TTY # no routine exists,
1456 and defined $ENV{TERM} # and we know what kind
1457 # of terminal this is,
1458 and $ENV{TERM} eq 'xterm' # and it's an xterm,
7fddc82f
RF
1459# and defined $ENV{WINDOWID} # and we know what window this is, <- wrong metric
1460 and defined $ENV{DISPLAY} # and what display it's on,
1461 )
69893cff 1462{
e22ea7cc 1463 *get_fork_TTY = \&xterm_get_fork_TTY; # use the xterm version
69893cff 1464} ## end if (not defined &get_fork_TTY...
e22ea7cc
RF
1465elsif ( $^O eq 'os2' ) { # If this is OS/2,
1466 *get_fork_TTY = \&os2_get_fork_TTY; # use the OS/2 version
f1583d8f 1467}
e22ea7cc 1468
dbb46cec
DQ
1469# untaint $^O, which may have been tainted by the last statement.
1470# see bug [perl #24674]
e22ea7cc
RF
1471$^O =~ m/^(.*)\z/;
1472$^O = $1;
f1583d8f 1473
d12a4851 1474# Here begin the unreadable code. It needs fixing.
055fd3a9 1475
69893cff
RGS
1476=head2 RESTART PROCESSING
1477
1478This section handles the restart command. When the C<R> command is invoked, it
1479tries to capture all of the state it can into environment variables, and
1480then sets C<PERLDB_RESTART>. When we start executing again, we check to see
1481if C<PERLDB_RESTART> is there; if so, we reload all the information that
1482the R command stuffed into the environment variables.
1483
1484 PERLDB_RESTART - flag only, contains no restart data itself.
1485 PERLDB_HIST - command history, if it's available
1486 PERLDB_ON_LOAD - breakpoints set by the rc file
1487 PERLDB_POSTPONE - subs that have been loaded/not executed, and have actions
1488 PERLDB_VISITED - files that had breakpoints
1489 PERLDB_FILE_... - breakpoints for a file
1490 PERLDB_OPT - active options
1491 PERLDB_INC - the original @INC
1492 PERLDB_PRETYPE - preprompt debugger actions
1493 PERLDB_PRE - preprompt Perl code
1494 PERLDB_POST - post-prompt Perl code
1495 PERLDB_TYPEAHEAD - typeahead captured by readline()
1496
1497We chug through all these variables and plug the values saved in them
1498back into the appropriate spots in the debugger.
1499
1500=cut
1501
e22ea7cc
RF
1502if ( exists $ENV{PERLDB_RESTART} ) {
1503
69893cff 1504 # We're restarting, so we don't need the flag that says to restart anymore.
e22ea7cc
RF
1505 delete $ENV{PERLDB_RESTART};
1506
1507 # $restart = 1;
1508 @hist = get_list('PERLDB_HIST');
1509 %break_on_load = get_list("PERLDB_ON_LOAD");
1510 %postponed = get_list("PERLDB_POSTPONE");
69893cff 1511
2cbb2ee1
RGS
1512 share(@hist);
1513 share(@truehist);
1514 share(%break_on_load);
1515 share(%postponed);
1516
69893cff 1517 # restore breakpoints/actions
e22ea7cc
RF
1518 my @had_breakpoints = get_list("PERLDB_VISITED");
1519 for ( 0 .. $#had_breakpoints ) {
1520 my %pf = get_list("PERLDB_FILE_$_");
1521 $postponed_file{ $had_breakpoints[$_] } = \%pf if %pf;
1522 }
69893cff
RGS
1523
1524 # restore options
e22ea7cc
RF
1525 my %opt = get_list("PERLDB_OPT");
1526 my ( $opt, $val );
1527 while ( ( $opt, $val ) = each %opt ) {
1528 $val =~ s/[\\\']/\\$1/g;
1529 parse_options("$opt'$val'");
1530 }
69893cff
RGS
1531
1532 # restore original @INC
e22ea7cc
RF
1533 @INC = get_list("PERLDB_INC");
1534 @ini_INC = @INC;
1535
1536 # return pre/postprompt actions and typeahead buffer
1537 $pretype = [ get_list("PERLDB_PRETYPE") ];
1538 $pre = [ get_list("PERLDB_PRE") ];
1539 $post = [ get_list("PERLDB_POST") ];
1540 @typeahead = get_list( "PERLDB_TYPEAHEAD", @typeahead );
69893cff
RGS
1541} ## end if (exists $ENV{PERLDB_RESTART...
1542
1543=head2 SETTING UP THE TERMINAL
1544
1545Now, we'll decide how the debugger is going to interact with the user.
1546If there's no TTY, we set the debugger to run non-stop; there's not going
1547to be anyone there to enter commands.
1548
1549=cut
54d04a52 1550
d338d6fe 1551if ($notty) {
69893cff 1552 $runnonstop = 1;
2cbb2ee1 1553 share($runnonstop);
69893cff 1554}
d12a4851 1555
69893cff
RGS
1556=pod
1557
1558If there is a TTY, we have to determine who it belongs to before we can
1559proceed. If this is a slave editor or graphical debugger (denoted by
1560the first command-line switch being '-emacs'), we shift this off and
1561set C<$rl> to 0 (XXX ostensibly to do straight reads).
1562
1563=cut
1564
1565else {
e22ea7cc 1566
69893cff
RGS
1567 # Is Perl being run from a slave editor or graphical debugger?
1568 # If so, don't use readline, and set $slave_editor = 1.
e22ea7cc
RF
1569 $slave_editor =
1570 ( ( defined $main::ARGV[0] ) and ( $main::ARGV[0] eq '-emacs' ) );
1571 $rl = 0, shift(@main::ARGV) if $slave_editor;
1572
1573 #require Term::ReadLine;
d12a4851 1574
69893cff
RGS
1575=pod
1576
1577We then determine what the console should be on various systems:
1578
1579=over 4
1580
1581=item * Cygwin - We use C<stdin> instead of a separate device.
1582
1583=cut
1584
e22ea7cc
RF
1585 if ( $^O eq 'cygwin' ) {
1586
69893cff
RGS
1587 # /dev/tty is binary. use stdin for textmode
1588 undef $console;
1589 }
1590
1591=item * Unix - use C</dev/tty>.
1592
1593=cut
1594
e22ea7cc 1595 elsif ( -e "/dev/tty" ) {
69893cff
RGS
1596 $console = "/dev/tty";
1597 }
1598
1599=item * Windows or MSDOS - use C<con>.
1600
1601=cut
1602
e22ea7cc 1603 elsif ( $^O eq 'dos' or -e "con" or $^O eq 'MSWin32' ) {
69893cff
RGS
1604 $console = "con";
1605 }
1606
1607=item * MacOS - use C<Dev:Console:Perl Debug> if this is the MPW version; C<Dev:
be9a9b1d
AT
1608Console> if not.
1609
1610Note 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
1611
1612=cut
1613
e22ea7cc
RF
1614 elsif ( $^O eq 'MacOS' ) {
1615 if ( $MacPerl::Version !~ /MPW/ ) {
1616 $console =
1617 "Dev:Console:Perl Debug"; # Separate window for application
69893cff
RGS
1618 }
1619 else {
1620 $console = "Dev:Console";
1621 }
1622 } ## end elsif ($^O eq 'MacOS')
1623
1624=item * VMS - use C<sys$command>.
1625
1626=cut
1627
1628 else {
e22ea7cc 1629
69893cff
RGS
1630 # everything else is ...
1631 $console = "sys\$command";
d12a4851 1632 }
69893cff
RGS
1633
1634=pod
1635
1636=back
1637
1638Several other systems don't use a specific console. We C<undef $console>
1639for those (Windows using a slave editor/graphical debugger, NetWare, OS/2
1640with a slave editor, Epoc).
1641
1642=cut
d12a4851 1643
e22ea7cc
RF
1644 if ( ( $^O eq 'MSWin32' ) and ( $slave_editor or defined $ENV{EMACS} ) ) {
1645
69893cff 1646 # /dev/tty is binary. use stdin for textmode
e22ea7cc
RF
1647 $console = undef;
1648 }
1649
1650 if ( $^O eq 'NetWare' ) {
d12a4851 1651
69893cff
RGS
1652 # /dev/tty is binary. use stdin for textmode
1653 $console = undef;
1654 }
d12a4851 1655
69893cff
RGS
1656 # In OS/2, we need to use STDIN to get textmode too, even though
1657 # it pretty much looks like Unix otherwise.
e22ea7cc
RF
1658 if ( defined $ENV{OS2_SHELL} and ( $slave_editor or $ENV{WINDOWID} ) )
1659 { # In OS/2
1660 $console = undef;
1661 }
1662
1663 # EPOC also falls into the 'got to use STDIN' camp.
1664 if ( $^O eq 'epoc' ) {
1665 $console = undef;
1666 }
d12a4851 1667
69893cff
RGS
1668=pod
1669
1670If there is a TTY hanging around from a parent, we use that as the console.
1671
1672=cut
1673
e22ea7cc 1674 $console = $tty if defined $tty;
d12a4851 1675
69893cff
RGS
1676=head2 SOCKET HANDLING
1677
1678The debugger is capable of opening a socket and carrying out a debugging
1679session over the socket.
1680
1681If C<RemotePort> was defined in the options, the debugger assumes that it
1682should try to start a debugging session on that port. It builds the socket
1683and then tries to connect the input and output filehandles to it.
1684
1685=cut
1686
1687 # Handle socket stuff.
e22ea7cc
RF
1688
1689 if ( defined $remoteport ) {
1690
69893cff
RGS
1691 # If RemotePort was defined in the options, connect input and output
1692 # to the socket.
e22ea7cc
RF
1693 require IO::Socket;
1694 $OUT = new IO::Socket::INET(
1695 Timeout => '10',
1696 PeerAddr => $remoteport,
1697 Proto => 'tcp',
69893cff 1698 );
e22ea7cc
RF
1699 if ( !$OUT ) { die "Unable to connect to remote host: $remoteport\n"; }
1700 $IN = $OUT;
69893cff
RGS
1701 } ## end if (defined $remoteport)
1702
1703=pod
1704
1705If no C<RemotePort> was defined, and we want to create a TTY on startup,
1706this is probably a situation where multiple debuggers are running (for example,
1707a backticked command that starts up another debugger). We create a new IN and
1708OUT filehandle, and do the necessary mojo to create a new TTY if we know how
1709and if we can.
1710
1711=cut
1712
1713 # Non-socket.
1714 else {
e22ea7cc 1715
69893cff
RGS
1716 # Two debuggers running (probably a system or a backtick that invokes
1717 # the debugger itself under the running one). create a new IN and OUT
e22ea7cc 1718 # filehandle, and do the necessary mojo to create a new tty if we
69893cff 1719 # know how, and we can.
e22ea7cc
RF
1720 create_IN_OUT(4) if $CreateTTY & 4;
1721 if ($console) {
1722
69893cff 1723 # If we have a console, check to see if there are separate ins and
cd1191f1 1724 # outs to open. (They are assumed identical if not.)
69893cff 1725
e22ea7cc
RF
1726 my ( $i, $o ) = split /,/, $console;
1727 $o = $i unless defined $o;
69893cff 1728
69893cff 1729 # read/write on in, or just read, or read on STDIN.
e22ea7cc
RF
1730 open( IN, "+<$i" )
1731 || open( IN, "<$i" )
1732 || open( IN, "<&STDIN" );
1733
69893cff
RGS
1734 # read/write/create/clobber out, or write/create/clobber out,
1735 # or merge with STDERR, or merge with STDOUT.
e22ea7cc
RF
1736 open( OUT, "+>$o" )
1737 || open( OUT, ">$o" )
1738 || open( OUT, ">&STDERR" )
1739 || open( OUT, ">&STDOUT" ); # so we don't dongle stdout
1740
1741 } ## end if ($console)
1742 elsif ( not defined $console ) {
1743
1744 # No console. Open STDIN.
1745 open( IN, "<&STDIN" );
1746
1747 # merge with STDERR, or with STDOUT.
1748 open( OUT, ">&STDERR" )
1749 || open( OUT, ">&STDOUT" ); # so we don't dongle stdout
1750 $console = 'STDIN/OUT';
69893cff
RGS
1751 } ## end elsif (not defined $console)
1752
1753 # Keep copies of the filehandles so that when the pager runs, it
1754 # can close standard input without clobbering ours.
e22ea7cc
RF
1755 $IN = \*IN, $OUT = \*OUT if $console or not defined $console;
1756 } ## end elsif (from if(defined $remoteport))
1757
1758 # Unbuffer DB::OUT. We need to see responses right away.
1759 my $previous = select($OUT);
1760 $| = 1; # for DB::OUT
1761 select($previous);
1762
1763 # Line info goes to debugger output unless pointed elsewhere.
1764 # Pointing elsewhere makes it possible for slave editors to
1765 # keep track of file and position. We have both a filehandle
1766 # and a I/O description to keep track of.
1767 $LINEINFO = $OUT unless defined $LINEINFO;
1768 $lineinfo = $console unless defined $lineinfo;
2cbb2ee1
RGS
1769 # share($LINEINFO); # <- unable to share globs
1770 share($lineinfo); #
e22ea7cc 1771
69893cff
RGS
1772=pod
1773
1774To finish initialization, we show the debugger greeting,
1775and then call the C<afterinit()> subroutine if there is one.
1776
1777=cut
d12a4851 1778
e22ea7cc
RF
1779 # Show the debugger greeting.
1780 $header =~ s/.Header: ([^,]+),v(\s+\S+\s+\S+).*$/$1$2/;
1781 unless ($runnonstop) {
1782 local $\ = '';
1783 local $, = '';
1784 if ( $term_pid eq '-1' ) {
1785 print $OUT "\nDaughter DB session started...\n";
1786 }
1787 else {
1788 print $OUT "\nLoading DB routines from $header\n";
1789 print $OUT (
1790 "Editor support ",
1791 $slave_editor ? "enabled" : "available", ".\n"
1792 );
1793 print $OUT
69893cff
RGS
1794"\nEnter h or `h h' for help, or `$doccmd perldebug' for more help.\n\n";
1795 } ## end else [ if ($term_pid eq '-1')
1796 } ## end unless ($runnonstop)
1797} ## end else [ if ($notty)
1798
1799# XXX This looks like a bug to me.
1800# Why copy to @ARGS and then futz with @args?
d338d6fe
PP
1801@ARGS = @ARGV;
1802for (@args) {
69893cff
RGS
1803 # Make sure backslashes before single quotes are stripped out, and
1804 # keep args unless they are numeric (XXX why?)
e22ea7cc
RF
1805 # s/\'/\\\'/g; # removed while not justified understandably
1806 # s/(.*)/'$1'/ unless /^-?[\d.]+$/; # ditto
d338d6fe
PP
1807}
1808
e22ea7cc 1809# If there was an afterinit() sub defined, call it. It will get
69893cff 1810# executed in our scope, so it can fiddle with debugger globals.
e22ea7cc 1811if ( defined &afterinit ) { # May be defined in $rcfile
69893cff 1812 &afterinit();
d338d6fe 1813}
e22ea7cc 1814
69893cff 1815# Inform us about "Stack dump during die enabled ..." in dieLevel().
43aed9ee
IZ
1816$I_m_init = 1;
1817
d338d6fe
PP
1818############################################################ Subroutines
1819
69893cff
RGS
1820=head1 SUBROUTINES
1821
1822=head2 DB
1823
1824This gigantic subroutine is the heart of the debugger. Called before every
1825statement, its job is to determine if a breakpoint has been reached, and
1826stop if so; read commands from the user, parse them, and execute
1827them, and hen send execution off to the next statement.
1828
1829Note that the order in which the commands are processed is very important;
1830some commands earlier in the loop will actually alter the C<$cmd> variable
be9a9b1d 1831to create other commands to be executed later. This is all highly I<optimized>
69893cff
RGS
1832but can be confusing. Check the comments for each C<$cmd ... && do {}> to
1833see what's happening in any given command.
1834
1835=cut
1836
d338d6fe 1837sub DB {
69893cff 1838
2cbb2ee1
RGS
1839 # lock the debugger and get the thread id for the prompt
1840 lock($DBGR);
1841 my $tid;
1842 if ($ENV{PERL5DB_THREADED}) {
1843 $tid = eval { "[".threads->self->tid."]" };
1844 }
1845
69893cff 1846 # Check for whether we should be running continuously or not.
36477c24 1847 # _After_ the perl program is compiled, $single is set to 1:
e22ea7cc
RF
1848 if ( $single and not $second_time++ ) {
1849
69893cff 1850 # Options say run non-stop. Run until we get an interrupt.
e22ea7cc
RF
1851 if ($runnonstop) { # Disable until signal
1852 # If there's any call stack in place, turn off single
1853 # stepping into subs throughout the stack.
1854 for ( $i = 0 ; $i <= $stack_depth ; ) {
1855 $stack[ $i++ ] &= ~1;
1856 }
1857
69893cff 1858 # And we are now no longer in single-step mode.
e22ea7cc 1859 $single = 0;
69893cff
RGS
1860
1861 # If we simply returned at this point, we wouldn't get
1862 # the trace info. Fall on through.
e22ea7cc 1863 # return;
69893cff
RGS
1864 } ## end if ($runnonstop)
1865
e22ea7cc
RF
1866 elsif ($ImmediateStop) {
1867
1868 # We are supposed to stop here; XXX probably a break.
1869 $ImmediateStop = 0; # We've processed it; turn it off
1870 $signal = 1; # Simulate an interrupt to force
1871 # us into the command loop
69893cff
RGS
1872 }
1873 } ## end if ($single and not $second_time...
1874
1875 # If we're in single-step mode, or an interrupt (real or fake)
1876 # has occurred, turn off non-stop mode.
1877 $runnonstop = 0 if $single or $signal;
1878
1879 # Preserve current values of $@, $!, $^E, $,, $/, $\, $^W.
1880 # The code being debugged may have altered them.
d338d6fe 1881 &save;
69893cff
RGS
1882
1883 # Since DB::DB gets called after every line, we can use caller() to
1884 # figure out where we last were executing. Sneaky, eh? This works because
e22ea7cc 1885 # caller is returning all the extra information when called from the
69893cff 1886 # debugger.
e22ea7cc 1887 local ( $package, $filename, $line ) = caller;
471505cc 1888 local $filename_ini = $filename;
69893cff
RGS
1889
1890 # set up the context for DB::eval, so it can properly execute
1891 # code on behalf of the user. We add the package in so that the
1892 # code is eval'ed in the proper package (not in the debugger!).
1893 local $usercontext =
e22ea7cc 1894 '($@, $!, $^E, $,, $/, $\, $^W) = @saved;' . "package $package;";
69893cff
RGS
1895
1896 # Create an alias to the active file magical array to simplify
1897 # the code here.
e22ea7cc 1898 local (*dbline) = $main::{ '_<' . $filename };
aa057b67
CN
1899
1900 # we need to check for pseudofiles on Mac OS (these are files
1901 # not attached to a filename, but instead stored in Dev:Pseudo)
e22ea7cc
RF
1902 if ( $^O eq 'MacOS' && $#dbline < 0 ) {
1903 $filename_ini = $filename = 'Dev:Pseudo';
1904 *dbline = $main::{ '_<' . $filename };
aa057b67
CN
1905 }
1906
69893cff 1907 # Last line in the program.
471505cc 1908 local $max = $#dbline;
69893cff
RGS
1909
1910 # if we have something here, see if we should break.
e22ea7cc
RF
1911 if ( $dbline{$line}
1912 && ( ( $stop, $action ) = split( /\0/, $dbline{$line} ) ) )
1913 {
1914
69893cff 1915 # Stop if the stop criterion says to just stop.
e22ea7cc 1916 if ( $stop eq '1' ) {
69893cff
RGS
1917 $signal |= 1;
1918 }
e22ea7cc 1919
69893cff
RGS
1920 # It's a conditional stop; eval it in the user's context and
1921 # see if we should stop. If so, remove the one-time sigil.
1922 elsif ($stop) {
e22ea7cc 1923 $evalarg = "\$DB::signal |= 1 if do {$stop}";
69893cff
RGS
1924 &eval;
1925 $dbline{$line} =~ s/;9($|\0)/$1/;
1926 }
1927 } ## end if ($dbline{$line} && ...
1928
1929 # Preserve the current stop-or-not, and see if any of the W
1930 # (watch expressions) has changed.
36477c24 1931 my $was_signal = $signal;
69893cff
RGS
1932
1933 # If we have any watch expressions ...
e22ea7cc
RF
1934 if ( $trace & 2 ) {
1935 for ( my $n = 0 ; $n <= $#to_watch ; $n++ ) {
1936 $evalarg = $to_watch[$n];
1937 local $onetimeDump; # Tell DB::eval() to not output results
69893cff
RGS
1938
1939 # Fix context DB::eval() wants to return an array, but
1940 # we need a scalar here.
e22ea7cc
RF
1941 my ($val) = join( "', '", &eval );
1942 $val = ( ( defined $val ) ? "'$val'" : 'undef' );
69893cff
RGS
1943
1944 # Did it change?
e22ea7cc
RF
1945 if ( $val ne $old_watch[$n] ) {
1946
69893cff 1947 # Yep! Show the difference, and fake an interrupt.
e22ea7cc
RF
1948 $signal = 1;
1949 print $OUT <<EOP;
405ff068 1950Watchpoint $n:\t$to_watch[$n] changed:
69893cff
RGS
1951 old value:\t$old_watch[$n]
1952 new value:\t$val
6027b9a3 1953EOP
e22ea7cc 1954 $old_watch[$n] = $val;
69893cff
RGS
1955 } ## end if ($val ne $old_watch...
1956 } ## end for (my $n = 0 ; $n <= ...
1957 } ## end if ($trace & 2)
1958
1959=head2 C<watchfunction()>
1960
1961C<watchfunction()> is a function that can be defined by the user; it is a
1962function which will be run on each entry to C<DB::DB>; it gets the
1963current package, filename, and line as its parameters.
1964
1965The watchfunction can do anything it likes; it is executing in the
1966debugger's context, so it has access to all of the debugger's internal
1967data structures and functions.
1968
1969C<watchfunction()> can control the debugger's actions. Any of the following
1970will cause the debugger to return control to the user's program after
1971C<watchfunction()> executes:
1972
1973=over 4
1974
be9a9b1d
AT
1975=item *
1976
1977Returning a false value from the C<watchfunction()> itself.
1978
1979=item *
1980
1981Altering C<$single> to a false value.
1982
1983=item *
69893cff 1984
be9a9b1d 1985Altering C<$signal> to a false value.
69893cff 1986
be9a9b1d 1987=item *
69893cff 1988
be9a9b1d 1989Turning off the C<4> bit in C<$trace> (this also disables the
69893cff
RGS
1990check for C<watchfunction()>. This can be done with
1991
1992 $trace &= ~4;
1993
1994=back
1995
1996=cut
1997
e22ea7cc 1998 # If there's a user-defined DB::watchfunction, call it with the
69893cff
RGS
1999 # current package, filename, and line. The function executes in
2000 # the DB:: package.
e22ea7cc
RF
2001 if ( $trace & 4 ) { # User-installed watch
2002 return
2003 if watchfunction( $package, $filename, $line )
2004 and not $single
2005 and not $was_signal
2006 and not( $trace & ~4 );
69893cff
RGS
2007 } ## end if ($trace & 4)
2008
e22ea7cc 2009 # Pick up any alteration to $signal in the watchfunction, and
69893cff 2010 # turn off the signal now.
6027b9a3 2011 $was_signal = $signal;
69893cff
RGS
2012 $signal = 0;
2013
2014=head2 GETTING READY TO EXECUTE COMMANDS
2015
2016The debugger decides to take control if single-step mode is on, the
2017C<t> command was entered, or the user generated a signal. If the program
2018has fallen off the end, we set things up so that entering further commands
2019won't cause trouble, and we say that the program is over.
2020
2021=cut
2022
2023 # Check to see if we should grab control ($single true,
2024 # trace set appropriately, or we got a signal).
e22ea7cc
RF
2025 if ( $single || ( $trace & 1 ) || $was_signal ) {
2026
69893cff 2027 # Yes, grab control.
e22ea7cc
RF
2028 if ($slave_editor) {
2029
69893cff 2030 # Tell the editor to update its position.
e22ea7cc
RF
2031 $position = "\032\032$filename:$line:0\n";
2032 print_lineinfo($position);
2033 }
69893cff
RGS
2034
2035=pod
2036
2037Special check: if we're in package C<DB::fake>, we've gone through the
2038C<END> block at least once. We set up everything so that we can continue
2039to enter commands and have a valid context to be in.
2040
2041=cut
2042
e22ea7cc 2043 elsif ( $package eq 'DB::fake' ) {
69893cff 2044
69893cff 2045 # Fallen off the end already.
e22ea7cc
RF
2046 $term || &setterm;
2047 print_help(<<EOP);
405ff068 2048Debugged program terminated. Use B<q> to quit or B<R> to restart,
6b27b0a0
BD
2049 use B<o> I<inhibit_exit> to avoid stopping after program termination,
2050 B<h q>, B<h R> or B<h o> to get additional info.
405ff068 2051EOP
e22ea7cc 2052
69893cff 2053 # Set the DB::eval context appropriately.
e22ea7cc
RF
2054 $package = 'main';
2055 $usercontext =
2056 '($@, $!, $^E, $,, $/, $\, $^W) = @saved;'
2057 . "package $package;"; # this won't let them modify, alas
69893cff 2058 } ## end elsif ($package eq 'DB::fake')
e219e2fb 2059
69893cff 2060=pod
e219e2fb 2061
69893cff
RGS
2062If the program hasn't finished executing, we scan forward to the
2063next executable line, print that out, build the prompt from the file and line
2064number information, and print that.
e219e2fb 2065
69893cff
RGS
2066=cut
2067
e22ea7cc
RF
2068 else {
2069
69893cff
RGS
2070 # Still somewhere in the midst of execution. Set up the
2071 # debugger prompt.
2072 $sub =~ s/\'/::/; # Swap Perl 4 package separators (') to
e22ea7cc 2073 # Perl 5 ones (sorry, we don't print Klingon
69893cff
RGS
2074 #module names)
2075
e22ea7cc
RF
2076 $prefix = $sub =~ /::/ ? "" : "${'package'}::";
2077 $prefix .= "$sub($filename:";
2078 $after = ( $dbline[$line] =~ /\n$/ ? '' : "\n" );
69893cff
RGS
2079
2080 # Break up the prompt if it's really long.
e22ea7cc
RF
2081 if ( length($prefix) > 30 ) {
2082 $position = "$prefix$line):\n$line:\t$dbline[$line]$after";
2083 $prefix = "";
2084 $infix = ":\t";
2085 }
2086 else {
2087 $infix = "):\t";
2088 $position = "$prefix$line$infix$dbline[$line]$after";
2089 }
69893cff
RGS
2090
2091 # Print current line info, indenting if necessary.
e22ea7cc
RF
2092 if ($frame) {
2093 print_lineinfo( ' ' x $stack_depth,
2094 "$line:\t$dbline[$line]$after" );
2095 }
2096 else {
2097 print_lineinfo($position);
2098 }
69893cff
RGS
2099
2100 # Scan forward, stopping at either the end or the next
2101 # unbreakable line.
e22ea7cc
RF
2102 for ( $i = $line + 1 ; $i <= $max && $dbline[$i] == 0 ; ++$i )
2103 { #{ vi
69893cff
RGS
2104
2105 # Drop out on null statements, block closers, and comments.
2106 last if $dbline[$i] =~ /^\s*[\;\}\#\n]/;
2107
2108 # Drop out if the user interrupted us.
2109 last if $signal;
2110
2111 # Append a newline if the line doesn't have one. Can happen
2112 # in eval'ed text, for instance.
e22ea7cc 2113 $after = ( $dbline[$i] =~ /\n$/ ? '' : "\n" );
69893cff
RGS
2114
2115 # Next executable line.
2116 $incr_pos = "$prefix$i$infix$dbline[$i]$after";
2117 $position .= $incr_pos;
2118 if ($frame) {
e22ea7cc 2119
69893cff 2120 # Print it indented if tracing is on.
e22ea7cc
RF
2121 print_lineinfo( ' ' x $stack_depth,
2122 "$i:\t$dbline[$i]$after" );
69893cff
RGS
2123 }
2124 else {
2125 print_lineinfo($incr_pos);
2126 }
2127 } ## end for ($i = $line + 1 ; $i...
2128 } ## end else [ if ($slave_editor)
2129 } ## end if ($single || ($trace...
2130
2131=pod
2132
2133If there's an action to be executed for the line we stopped at, execute it.
2134If there are any preprompt actions, execute those as well.
e219e2fb
RF
2135
2136=cut
2137
69893cff
RGS
2138 # If there's an action, do it now.
2139 $evalarg = $action, &eval if $action;
e219e2fb 2140
69893cff
RGS
2141 # Are we nested another level (e.g., did we evaluate a function
2142 # that had a breakpoint in it at the debugger prompt)?
e22ea7cc
RF
2143 if ( $single || $was_signal ) {
2144
69893cff 2145 # Yes, go down a level.
e22ea7cc 2146 local $level = $level + 1;
69893cff
RGS
2147
2148 # Do any pre-prompt actions.
e22ea7cc
RF
2149 foreach $evalarg (@$pre) {
2150 &eval;
2151 }
69893cff
RGS
2152
2153 # Complain about too much recursion if we passed the limit.
e22ea7cc 2154 print $OUT $stack_depth . " levels deep in subroutine calls!\n"
69893cff
RGS
2155 if $single & 4;
2156
2157 # The line we're currently on. Set $incr to -1 to stay here
2158 # until we get a command that tells us to advance.
e22ea7cc
RF
2159 $start = $line;
2160 $incr = -1; # for backward motion.
69893cff
RGS
2161
2162 # Tack preprompt debugger actions ahead of any actual input.
e22ea7cc 2163 @typeahead = ( @$pretype, @typeahead );
69893cff
RGS
2164
2165=head2 WHERE ARE WE?
2166
2167XXX Relocate this section?
2168
2169The debugger normally shows the line corresponding to the current line of
2170execution. Sometimes, though, we want to see the next line, or to move elsewhere
2171in the file. This is done via the C<$incr>, C<$start>, and C<$max> variables.
2172
be9a9b1d
AT
2173C<$incr> controls by how many lines the I<current> line should move forward
2174after a command is executed. If set to -1, this indicates that the I<current>
69893cff
RGS
2175line shouldn't change.
2176
be9a9b1d 2177C<$start> is the I<current> line. It is used for things like knowing where to
69893cff
RGS
2178move forwards or backwards from when doing an C<L> or C<-> command.
2179
2180C<$max> tells the debugger where the last line of the current file is. It's
2181used to terminate loops most often.
2182
2183=head2 THE COMMAND LOOP
2184
2185Most of C<DB::DB> is actually a command parsing and dispatch loop. It comes
2186in two parts:
2187
2188=over 4
2189
be9a9b1d
AT
2190=item *
2191
2192The outer part of the loop, starting at the C<CMD> label. This loop
69893cff
RGS
2193reads a command and then executes it.
2194
be9a9b1d
AT
2195=item *
2196
2197The inner part of the loop, starting at the C<PIPE> label. This part
69893cff
RGS
2198is wholly contained inside the C<CMD> block and only executes a command.
2199Used to handle commands running inside a pager.
2200
2201=back
2202
2203So why have two labels to restart the loop? Because sometimes, it's easier to
2204have a command I<generate> another command and then re-execute the loop to do
2205the new command. This is faster, but perhaps a bit more convoluted.
2206
2207=cut
2208
2209 # The big command dispatch loop. It keeps running until the
2210 # user yields up control again.
2211 #
2212 # If we have a terminal for input, and we get something back
2213 # from readline(), keep on processing.
e22ea7cc
RF
2214 CMD:
2215 while (
2216
69893cff 2217 # We have a terminal, or can get one ...
e22ea7cc
RF
2218 ( $term || &setterm ),
2219
69893cff 2220 # ... and it belogs to this PID or we get one for this PID ...
e22ea7cc
RF
2221 ( $term_pid == $$ or resetterm(1) ),
2222
69893cff 2223 # ... and we got a line of command input ...
e22ea7cc
RF
2224 defined(
2225 $cmd = &readline(
2cbb2ee1 2226 "$pidprompt $tid DB"
e22ea7cc
RF
2227 . ( '<' x $level )
2228 . ( $#hist + 1 )
2229 . ( '>' x $level ) . " "
69893cff
RGS
2230 )
2231 )
2232 )
2233 {
e22ea7cc 2234
2cbb2ee1 2235 share($cmd);
69893cff
RGS
2236 # ... try to execute the input as debugger commands.
2237
2238 # Don't stop running.
2239 $single = 0;
2240
2241 # No signal is active.
2242 $signal = 0;
2243
2244 # Handle continued commands (ending with \):
e22ea7cc
RF
2245 $cmd =~ s/\\$/\n/ && do {
2246 $cmd .= &readline(" cont: ");
2247 redo CMD;
2248 };
69893cff
RGS
2249
2250=head4 The null command
2251
be9a9b1d 2252A newline entered by itself means I<re-execute the last command>. We grab the
69893cff
RGS
2253command out of C<$laststep> (where it was recorded previously), and copy it
2254back into C<$cmd> to be executed below. If there wasn't any previous command,
2255we'll do nothing below (no command will match). If there was, we also save it
2256in the command history and fall through to allow the command parsing to pick
2257it up.
2258
2259=cut
2260
2261 # Empty input means repeat the last command.
e22ea7cc
RF
2262 $cmd =~ /^$/ && ( $cmd = $laststep );
2263 chomp($cmd); # get rid of the annoying extra newline
2264 push( @hist, $cmd ) if length($cmd) > 1;
2265 push( @truehist, $cmd );
2cbb2ee1
RGS
2266 share(@hist);
2267 share(@truehist);
e22ea7cc
RF
2268
2269 # This is a restart point for commands that didn't arrive
2270 # via direct user input. It allows us to 'redo PIPE' to
2271 # re-execute command processing without reading a new command.
69893cff 2272 PIPE: {
e22ea7cc
RF
2273 $cmd =~ s/^\s+//s; # trim annoying leading whitespace
2274 $cmd =~ s/\s+$//s; # trim annoying trailing whitespace
2275 ($i) = split( /\s+/, $cmd );
69893cff
RGS
2276
2277=head3 COMMAND ALIASES
2278
2279The debugger can create aliases for commands (these are stored in the
2280C<%alias> hash). Before a command is executed, the command loop looks it up
2281in the alias hash and substitutes the contents of the alias for the command,
2282completely replacing it.
2283
2284=cut
2285
2286 # See if there's an alias for the command, and set it up if so.
e22ea7cc
RF
2287 if ( $alias{$i} ) {
2288
69893cff
RGS
2289 # Squelch signal handling; we want to keep control here
2290 # if something goes loco during the alias eval.
2291 local $SIG{__DIE__};
2292 local $SIG{__WARN__};
2293
2294 # This is a command, so we eval it in the DEBUGGER's
2295 # scope! Otherwise, we can't see the special debugger
2296 # variables, or get to the debugger's subs. (Well, we
2297 # _could_, but why make it even more complicated?)
2298 eval "\$cmd =~ $alias{$i}";
2299 if ($@) {
2300 local $\ = '';
2301 print $OUT "Couldn't evaluate `$i' alias: $@";
2302 next CMD;
2303 }
2304 } ## end if ($alias{$i})
2305
2306=head3 MAIN-LINE COMMANDS
2307
2308All of these commands work up to and after the program being debugged has
2309terminated.
2310
2311=head4 C<q> - quit
2312
2313Quit the debugger. This entails setting the C<$fall_off_end> flag, so we don't
2314try to execute further, cleaning any restart-related stuff out of the
2315environment, and executing with the last value of C<$?>.
2316
2317=cut
2318
2319 $cmd =~ /^q$/ && do {
2320 $fall_off_end = 1;
2321 clean_ENV();
2322 exit $?;
2323 };
2324
2325=head4 C<t> - trace
2326
2327Turn tracing on or off. Inverts the appropriate bit in C<$trace> (q.v.).
2328
2329=cut
2330
e22ea7cc
RF
2331 $cmd =~ /^t$/ && do {
2332 $trace ^= 1;
2333 local $\ = '';
2334 print $OUT "Trace = "
2335 . ( ( $trace & 1 ) ? "on" : "off" ) . "\n";
2336 next CMD;
2337 };
69893cff
RGS
2338
2339=head4 C<S> - list subroutines matching/not matching a pattern
2340
2341Walks through C<%sub>, checking to see whether or not to print the name.
2342
2343=cut
2344
e22ea7cc 2345 $cmd =~ /^S(\s+(!)?(.+))?$/ && do {
69893cff 2346
e22ea7cc 2347 $Srev = defined $2; # Reverse scan?
69893cff
RGS
2348 $Spatt = $3; # The pattern (if any) to use.
2349 $Snocheck = !defined $1; # No args - print all subs.
2350
2351 # Need to make these sane here.
e22ea7cc
RF
2352 local $\ = '';
2353 local $, = '';
69893cff
RGS
2354
2355 # Search through the debugger's magical hash of subs.
2356 # If $nocheck is true, just print the sub name.
2357 # Otherwise, check it against the pattern. We then use
2358 # the XOR trick to reverse the condition as required.
e22ea7cc
RF
2359 foreach $subname ( sort( keys %sub ) ) {
2360 if ( $Snocheck or $Srev ^ ( $subname =~ /$Spatt/ ) ) {
2361 print $OUT $subname, "\n";
2362 }
2363 }
2364 next CMD;
2365 };
69893cff
RGS
2366
2367=head4 C<X> - list variables in current package
2368
2369Since the C<V> command actually processes this, just change this to the
2370appropriate C<V> command and fall through.
2371
2372=cut
2373
e22ea7cc 2374 $cmd =~ s/^X\b/V $package/;
69893cff
RGS
2375
2376=head4 C<V> - list variables
2377
2378Uses C<dumpvar.pl> to dump out the current values for selected variables.
2379
2380=cut
2381
2382 # Bare V commands get the currently-being-debugged package
2383 # added.
e22ea7cc
RF
2384 $cmd =~ /^V$/ && do {
2385 $cmd = "V $package";
2386 };
69893cff
RGS
2387
2388 # V - show variables in package.
2389 $cmd =~ /^V\b\s*(\S+)\s*(.*)/ && do {
e22ea7cc 2390
69893cff
RGS
2391 # Save the currently selected filehandle and
2392 # force output to debugger's filehandle (dumpvar
2393 # just does "print" for output).
e22ea7cc 2394 local ($savout) = select($OUT);
69893cff
RGS
2395
2396 # Grab package name and variables to dump.
e22ea7cc
RF
2397 $packname = $1;
2398 @vars = split( ' ', $2 );
69893cff
RGS
2399
2400 # If main::dumpvar isn't here, get it.
e22ea7cc
RF
2401 do 'dumpvar.pl' unless defined &main::dumpvar;
2402 if ( defined &main::dumpvar ) {
2403
69893cff
RGS
2404 # We got it. Turn off subroutine entry/exit messages
2405 # for the moment, along with return values.
e22ea7cc
RF
2406 local $frame = 0;
2407 local $doret = -2;
69893cff
RGS
2408
2409 # must detect sigpipe failures - not catching
2410 # then will cause the debugger to die.
2411 eval {
2412 &main::dumpvar(
2413 $packname,
2414 defined $option{dumpDepth}
e22ea7cc
RF
2415 ? $option{dumpDepth}
2416 : -1, # assume -1 unless specified
69893cff 2417 @vars
e22ea7cc
RF
2418 );
2419 };
2420
2421 # The die doesn't need to include the $@, because
2422 # it will automatically get propagated for us.
2423 if ($@) {
2424 die unless $@ =~ /dumpvar print failed/;
2425 }
2426 } ## end if (defined &main::dumpvar)
2427 else {
2428
2429 # Couldn't load dumpvar.
2430 print $OUT "dumpvar.pl not available.\n";
2431 }
69893cff 2432
69893cff 2433 # Restore the output filehandle, and go round again.
e22ea7cc
RF
2434 select($savout);
2435 next CMD;
2436 };
69893cff
RGS
2437
2438=head4 C<x> - evaluate and print an expression
2439
2440Hands the expression off to C<DB::eval>, setting it up to print the value
2441via C<dumpvar.pl> instead of just printing it directly.
2442
2443=cut
2444
e22ea7cc
RF
2445 $cmd =~ s/^x\b/ / && do { # Remainder gets done by DB::eval()
2446 $onetimeDump = 'dump'; # main::dumpvar shows the output
69893cff
RGS
2447
2448 # handle special "x 3 blah" syntax XXX propagate
2449 # doc back to special variables.
e22ea7cc
RF
2450 if ( $cmd =~ s/^\s*(\d+)(?=\s)/ / ) {
2451 $onetimedumpDepth = $1;
2452 }
2453 };
69893cff
RGS
2454
2455=head4 C<m> - print methods
2456
2457Just uses C<DB::methods> to determine what methods are available.
2458
2459=cut
2460
e22ea7cc
RF
2461 $cmd =~ s/^m\s+([\w:]+)\s*$/ / && do {
2462 methods($1);
2463 next CMD;
2464 };
69893cff
RGS
2465
2466 # m expr - set up DB::eval to do the work
e22ea7cc
RF
2467 $cmd =~ s/^m\b/ / && do { # Rest gets done by DB::eval()
2468 $onetimeDump = 'methods'; # method output gets used there
2469 };
69893cff
RGS
2470
2471=head4 C<f> - switch files
2472
2473=cut
2474
e22ea7cc
RF
2475 $cmd =~ /^f\b\s*(.*)/ && do {
2476 $file = $1;
2477 $file =~ s/\s+$//;
69893cff
RGS
2478
2479 # help for no arguments (old-style was return from sub).
e22ea7cc
RF
2480 if ( !$file ) {
2481 print $OUT
2482 "The old f command is now the r command.\n"; # hint
2483 print $OUT "The new f command switches filenames.\n";
2484 next CMD;
2485 } ## end if (!$file)
69893cff
RGS
2486
2487 # if not in magic file list, try a close match.
e22ea7cc
RF
2488 if ( !defined $main::{ '_<' . $file } ) {
2489 if ( ($try) = grep( m#^_<.*$file#, keys %main:: ) ) {
2490 {
2491 $try = substr( $try, 2 );
2492 print $OUT "Choosing $try matching `$file':\n";
2493 $file = $try;
2494 }
2495 } ## end if (($try) = grep(m#^_<.*$file#...
2496 } ## end if (!defined $main::{ ...
69893cff
RGS
2497
2498 # If not successfully switched now, we failed.
e22ea7cc
RF
2499 if ( !defined $main::{ '_<' . $file } ) {
2500 print $OUT "No file matching `$file' is loaded.\n";
2501 next CMD;
2502 }
69893cff 2503
e22ea7cc
RF
2504 # We switched, so switch the debugger internals around.
2505 elsif ( $file ne $filename ) {
2506 *dbline = $main::{ '_<' . $file };
2507 $max = $#dbline;
2508 $filename = $file;
2509 $start = 1;
2510 $cmd = "l";
2511 } ## end elsif ($file ne $filename)
2512
2513 # We didn't switch; say we didn't.
2514 else {
2515 print $OUT "Already in $file.\n";
2516 next CMD;
2517 }
2518 };
69893cff
RGS
2519
2520=head4 C<.> - return to last-executed line.
2521
2522We set C<$incr> to -1 to indicate that the debugger shouldn't move ahead,
2523and then we look up the line in the magical C<%dbline> hash.
2524
2525=cut
2526
2527 # . command.
e22ea7cc
RF
2528 $cmd =~ /^\.$/ && do {
2529 $incr = -1; # stay at current line
69893cff
RGS
2530
2531 # Reset everything to the old location.
e22ea7cc
RF
2532 $start = $line;
2533 $filename = $filename_ini;
2534 *dbline = $main::{ '_<' . $filename };
2535 $max = $#dbline;
69893cff
RGS
2536
2537 # Now where are we?
e22ea7cc
RF
2538 print_lineinfo($position);
2539 next CMD;
2540 };
69893cff
RGS
2541
2542=head4 C<-> - back one window
2543
2544We change C<$start> to be one window back; if we go back past the first line,
2545we set it to be the first line. We ser C<$incr> to put us back at the
2546currently-executing line, and then put a C<l $start +> (list one window from
2547C<$start>) in C<$cmd> to be executed later.
2548
2549=cut
2550
2551 # - - back a window.
e22ea7cc
RF
2552 $cmd =~ /^-$/ && do {
2553
69893cff 2554 # back up by a window; go to 1 if back too far.
e22ea7cc
RF
2555 $start -= $incr + $window + 1;
2556 $start = 1 if $start <= 0;
2557 $incr = $window - 1;
69893cff
RGS
2558
2559 # Generate and execute a "l +" command (handled below).
e22ea7cc
RF
2560 $cmd = 'l ' . ($start) . '+';
2561 };
69893cff
RGS
2562
2563=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>, {, {{>
2564
2565In Perl 5.8.0, a realignment of the commands was done to fix up a number of
2566problems, most notably that the default case of several commands destroying
2567the user's work in setting watchpoints, actions, etc. We wanted, however, to
2568retain the old commands for those who were used to using them or who preferred
2569them. At this point, we check for the new commands and call C<cmd_wrapper> to
2570deal with them instead of processing them in-line.
2571
2572=cut
2573
2574 # All of these commands were remapped in perl 5.8.0;
e22ea7cc 2575 # we send them off to the secondary dispatcher (see below).
2cbb2ee1 2576 $cmd =~ /^([aAbBeEhilLMoOPvwW]\b|[<>\{]{1,2})\s*(.*)/so && do {
e22ea7cc
RF
2577 &cmd_wrapper( $1, $2, $line );
2578 next CMD;
2579 };
69893cff
RGS
2580
2581=head4 C<y> - List lexicals in higher scope
2582
2583Uses C<PadWalker> to find the lexicals supplied as arguments in a scope
2584above the current one and then displays then using C<dumpvar.pl>.
2585
2586=cut
2587
2588 $cmd =~ /^y(?:\s+(\d*)\s*(.*))?$/ && do {
2589
2590 # See if we've got the necessary support.
2591 eval { require PadWalker; PadWalker->VERSION(0.08) }
2592 or &warn(
2593 $@ =~ /locate/
2594 ? "PadWalker module not found - please install\n"
2595 : $@
2596 )
2597 and next CMD;
2598
2599 # Load up dumpvar if we don't have it. If we can, that is.
2600 do 'dumpvar.pl' unless defined &main::dumpvar;
2601 defined &main::dumpvar
2602 or print $OUT "dumpvar.pl not available.\n"
2603 and next CMD;
2604
2605 # Got all the modules we need. Find them and print them.
e22ea7cc 2606 my @vars = split( ' ', $2 || '' );
69893cff
RGS
2607
2608 # Find the pad.
e22ea7cc 2609 my $h = eval { PadWalker::peek_my( ( $1 || 0 ) + 1 ) };
69893cff
RGS
2610
2611 # Oops. Can't find it.
2612 $@ and $@ =~ s/ at .*//, &warn($@), next CMD;
2613
2614 # Show the desired vars with dumplex().
2615 my $savout = select($OUT);
2616
2617 # Have dumplex dump the lexicals.
e22ea7cc 2618 dumpvar::dumplex( $_, $h->{$_},
69893cff 2619 defined $option{dumpDepth} ? $option{dumpDepth} : -1,
e22ea7cc
RF
2620 @vars )
2621 for sort keys %$h;
69893cff
RGS
2622 select($savout);
2623 next CMD;
2624 };
2625
2626=head3 COMMANDS NOT WORKING AFTER PROGRAM ENDS
2627
2628All of the commands below this point don't work after the program being
2629debugged has ended. All of them check to see if the program has ended; this
2630allows the commands to be relocated without worrying about a 'line of
2631demarcation' above which commands can be entered anytime, and below which
2632they can't.
2633
2634=head4 C<n> - single step, but don't trace down into subs
2635
2636Done by setting C<$single> to 2, which forces subs to execute straight through
be9a9b1d 2637when entered (see C<DB::sub>). We also save the C<n> command in C<$laststep>,
69893cff
RGS
2638so a null command knows what to re-execute.
2639
2640=cut
2641
e22ea7cc 2642 # n - next
69893cff
RGS
2643 $cmd =~ /^n$/ && do {
2644 end_report(), next CMD if $finished and $level <= 1;
e22ea7cc 2645
69893cff
RGS
2646 # Single step, but don't enter subs.
2647 $single = 2;
e22ea7cc 2648
69893cff 2649 # Save for empty command (repeat last).
e22ea7cc
RF
2650 $laststep = $cmd;
2651 last CMD;
2652 };
69893cff
RGS
2653
2654=head4 C<s> - single-step, entering subs
2655
be9a9b1d 2656Sets C<$single> to 1, which causes C<DB::sub> to continue tracing inside
69893cff
RGS
2657subs. Also saves C<s> as C<$lastcmd>.
2658
2659=cut
2660
2661 # s - single step.
2662 $cmd =~ /^s$/ && do {
e22ea7cc 2663
69893cff
RGS
2664 # Get out and restart the command loop if program
2665 # has finished.
e22ea7cc
RF
2666 end_report(), next CMD if $finished and $level <= 1;
2667
69893cff 2668 # Single step should enter subs.
e22ea7cc
RF
2669 $single = 1;
2670
69893cff 2671 # Save for empty command (repeat last).
e22ea7cc
RF
2672 $laststep = $cmd;
2673 last CMD;
2674 };
69893cff
RGS
2675
2676=head4 C<c> - run continuously, setting an optional breakpoint
2677
2678Most of the code for this command is taken up with locating the optional
2679breakpoint, which is either a subroutine name or a line number. We set
2680the appropriate one-time-break in C<@dbline> and then turn off single-stepping
2681in this and all call levels above this one.
2682
2683=cut
2684
2685 # c - start continuous execution.
2686 $cmd =~ /^c\b\s*([\w:]*)\s*$/ && do {
e22ea7cc 2687
69893cff
RGS
2688 # Hey, show's over. The debugged program finished
2689 # executing already.
2690 end_report(), next CMD if $finished and $level <= 1;
2691
2692 # Capture the place to put a one-time break.
2693 $subname = $i = $1;
2694
e22ea7cc
RF
2695 # Probably not needed, since we finish an interactive
2696 # sub-session anyway...
2697 # local $filename = $filename;
2698 # local *dbline = *dbline; # XXX Would this work?!
69893cff
RGS
2699 #
2700 # The above question wonders if localizing the alias
2701 # to the magic array works or not. Since it's commented
2702 # out, we'll just leave that to speculation for now.
2703
2704 # If the "subname" isn't all digits, we'll assume it
2705 # is a subroutine name, and try to find it.
e22ea7cc
RF
2706 if ( $subname =~ /\D/ ) { # subroutine name
2707 # Qualify it to the current package unless it's
2708 # already qualified.
69893cff
RGS
2709 $subname = $package . "::" . $subname
2710 unless $subname =~ /::/;
e22ea7cc 2711
69893cff
RGS
2712 # find_sub will return "file:line_number" corresponding
2713 # to where the subroutine is defined; we call find_sub,
e22ea7cc 2714 # break up the return value, and assign it in one
69893cff 2715 # operation.
e22ea7cc 2716 ( $file, $i ) = ( find_sub($subname) =~ /^(.*):(.*)$/ );
69893cff
RGS
2717
2718 # Force the line number to be numeric.
e22ea7cc 2719 $i += 0;
69893cff
RGS
2720
2721 # If we got a line number, we found the sub.
e22ea7cc
RF
2722 if ($i) {
2723
69893cff
RGS
2724 # Switch all the debugger's internals around so
2725 # we're actually working with that file.
e22ea7cc
RF
2726 $filename = $file;
2727 *dbline = $main::{ '_<' . $filename };
2728
69893cff 2729 # Mark that there's a breakpoint in this file.
e22ea7cc
RF
2730 $had_breakpoints{$filename} |= 1;
2731
69893cff
RGS
2732 # Scan forward to the first executable line
2733 # after the 'sub whatever' line.
e22ea7cc
RF
2734 $max = $#dbline;
2735 ++$i while $dbline[$i] == 0 && $i < $max;
2736 } ## end if ($i)
69893cff
RGS
2737
2738 # We didn't find a sub by that name.
e22ea7cc
RF
2739 else {
2740 print $OUT "Subroutine $subname not found.\n";
2741 next CMD;
2742 }
2743 } ## end if ($subname =~ /\D/)
69893cff
RGS
2744
2745 # At this point, either the subname was all digits (an
2746 # absolute line-break request) or we've scanned through
2747 # the code following the definition of the sub, looking
2748 # for an executable, which we may or may not have found.
2749 #
2750 # If $i (which we set $subname from) is non-zero, we
e22ea7cc
RF
2751 # got a request to break at some line somewhere. On
2752 # one hand, if there wasn't any real subroutine name
2753 # involved, this will be a request to break in the current
2754 # file at the specified line, so we have to check to make
69893cff
RGS
2755 # sure that the line specified really is breakable.
2756 #
2757 # On the other hand, if there was a subname supplied, the
3c4b39be 2758 # preceding block has moved us to the proper file and
69893cff
RGS
2759 # location within that file, and then scanned forward
2760 # looking for the next executable line. We have to make
2761 # sure that one was found.
2762 #
2763 # On the gripping hand, we can't do anything unless the
2764 # current value of $i points to a valid breakable line.
2765 # Check that.
e22ea7cc
RF
2766 if ($i) {
2767
69893cff 2768 # Breakable?
e22ea7cc
RF
2769 if ( $dbline[$i] == 0 ) {
2770 print $OUT "Line $i not breakable.\n";
2771 next CMD;
2772 }
2773
69893cff 2774 # Yes. Set up the one-time-break sigil.
e22ea7cc
RF
2775 $dbline{$i} =~ s/($|\0)/;9$1/; # add one-time-only b.p.
2776 } ## end if ($i)
69893cff
RGS
2777
2778 # Turn off stack tracing from here up.
e22ea7cc
RF
2779 for ( $i = 0 ; $i <= $stack_depth ; ) {
2780 $stack[ $i++ ] &= ~1;
2781 }
2782 last CMD;
2783 };
69893cff
RGS
2784
2785=head4 C<r> - return from a subroutine
2786
2787For C<r> to work properly, the debugger has to stop execution again
2788immediately after the return is executed. This is done by forcing
2789single-stepping to be on in the call level above the current one. If
2790we are printing return values when a C<r> is executed, set C<$doret>
2791appropriately, and force us out of the command loop.
2792
2793=cut
2794
2795 # r - return from the current subroutine.
e22ea7cc
RF
2796 $cmd =~ /^r$/ && do {
2797
69893cff 2798 # Can't do anythign if the program's over.
e22ea7cc
RF
2799 end_report(), next CMD if $finished and $level <= 1;
2800
69893cff 2801 # Turn on stack trace.
e22ea7cc
RF
2802 $stack[$stack_depth] |= 1;
2803
69893cff 2804 # Print return value unless the stack is empty.
e22ea7cc
RF
2805 $doret = $option{PrintRet} ? $stack_depth - 1 : -2;
2806 last CMD;
2807 };
69893cff 2808
69893cff
RGS
2809=head4 C<T> - stack trace
2810
2811Just calls C<DB::print_trace>.
2812
2813=cut
2814
e22ea7cc
RF
2815 $cmd =~ /^T$/ && do {
2816 print_trace( $OUT, 1 ); # skip DB
2817 next CMD;
2818 };
69893cff
RGS
2819
2820=head4 C<w> - List window around current line.
2821
2822Just calls C<DB::cmd_w>.
2823
2824=cut
2825
e22ea7cc 2826 $cmd =~ /^w\b\s*(.*)/s && do { &cmd_w( 'w', $1 ); next CMD; };
69893cff
RGS
2827
2828=head4 C<W> - watch-expression processing.
2829
2830Just calls C<DB::cmd_W>.
2831
2832=cut
2833
e22ea7cc 2834 $cmd =~ /^W\b\s*(.*)/s && do { &cmd_W( 'W', $1 ); next CMD; };
69893cff
RGS
2835
2836=head4 C</> - search forward for a string in the source
2837
2838We take the argument and treat it as a pattern. If it turns out to be a
2839bad one, we return the error we got from trying to C<eval> it and exit.
2840If not, we create some code to do the search and C<eval> it so it can't
2841mess us up.
2842
2843=cut
2844
e22ea7cc 2845 $cmd =~ /^\/(.*)$/ && do {
69893cff
RGS
2846
2847 # The pattern as a string.
e22ea7cc 2848 $inpat = $1;
69893cff
RGS
2849
2850 # Remove the final slash.
e22ea7cc 2851 $inpat =~ s:([^\\])/$:$1:;
69893cff
RGS
2852
2853 # If the pattern isn't null ...
e22ea7cc 2854 if ( $inpat ne "" ) {
69893cff
RGS
2855
2856 # Turn of warn and die procesing for a bit.
e22ea7cc
RF
2857 local $SIG{__DIE__};
2858 local $SIG{__WARN__};
69893cff
RGS
2859
2860 # Create the pattern.
e22ea7cc
RF
2861 eval '$inpat =~ m' . "\a$inpat\a";
2862 if ( $@ ne "" ) {
2863
69893cff 2864 # Oops. Bad pattern. No biscuit.
e22ea7cc 2865 # Print the eval error and go back for more
69893cff 2866 # commands.
e22ea7cc
RF
2867 print $OUT "$@";
2868 next CMD;
2869 }
2870 $pat = $inpat;
2871 } ## end if ($inpat ne "")
69893cff
RGS
2872
2873 # Set up to stop on wrap-around.
e22ea7cc 2874 $end = $start;
69893cff
RGS
2875
2876 # Don't move off the current line.
e22ea7cc 2877 $incr = -1;
69893cff
RGS
2878
2879 # Done in eval so nothing breaks if the pattern
2880 # does something weird.
e22ea7cc
RF
2881 eval '
2882 for (;;) {
69893cff 2883 # Move ahead one line.
e22ea7cc 2884 ++$start;
69893cff
RGS
2885
2886 # Wrap if we pass the last line.
e22ea7cc 2887 $start = 1 if ($start > $max);
69893cff
RGS
2888
2889 # Stop if we have gotten back to this line again,
e22ea7cc 2890 last if ($start == $end);
69893cff
RGS
2891
2892 # A hit! (Note, though, that we are doing
2893 # case-insensitive matching. Maybe a qr//
2894 # expression would be better, so the user could
2895 # do case-sensitive matching if desired.
e22ea7cc
RF
2896 if ($dbline[$start] =~ m' . "\a$pat\a" . 'i) {
2897 if ($slave_editor) {
69893cff 2898 # Handle proper escaping in the slave.
e22ea7cc
RF
2899 print $OUT "\032\032$filename:$start:0\n";
2900 }
2901 else {
69893cff 2902 # Just print the line normally.
e22ea7cc
RF
2903 print $OUT "$start:\t",$dbline[$start],"\n";
2904 }
69893cff 2905 # And quit since we found something.
e22ea7cc
RF
2906 last;
2907 }
2908 } ';
2909
69893cff 2910 # If we wrapped, there never was a match.
e22ea7cc
RF
2911 print $OUT "/$pat/: not found\n" if ( $start == $end );
2912 next CMD;
2913 };
69893cff
RGS
2914
2915=head4 C<?> - search backward for a string in the source
2916
2917Same as for C</>, except the loop runs backwards.
2918
2919=cut
2920
2921 # ? - backward pattern search.
e22ea7cc 2922 $cmd =~ /^\?(.*)$/ && do {
69893cff
RGS
2923
2924 # Get the pattern, remove trailing question mark.
e22ea7cc
RF
2925 $inpat = $1;
2926 $inpat =~ s:([^\\])\?$:$1:;
69893cff
RGS
2927
2928 # If we've got one ...
e22ea7cc 2929 if ( $inpat ne "" ) {
69893cff
RGS
2930
2931 # Turn off die & warn handlers.
e22ea7cc
RF
2932 local $SIG{__DIE__};
2933 local $SIG{__WARN__};
2934 eval '$inpat =~ m' . "\a$inpat\a";
2935
2936 if ( $@ ne "" ) {
2937
69893cff 2938 # Ouch. Not good. Print the error.
e22ea7cc
RF
2939 print $OUT $@;
2940 next CMD;
2941 }
2942 $pat = $inpat;
69893cff 2943 } ## end if ($inpat ne "")
e22ea7cc 2944
69893cff 2945 # Where we are now is where to stop after wraparound.
e22ea7cc 2946 $end = $start;
69893cff
RGS
2947
2948 # Don't move away from this line.
e22ea7cc 2949 $incr = -1;
69893cff
RGS
2950
2951 # Search inside the eval to prevent pattern badness
2952 # from killing us.
e22ea7cc
RF
2953 eval '
2954 for (;;) {
69893cff 2955 # Back up a line.
e22ea7cc 2956 --$start;
69893cff
RGS
2957
2958 # Wrap if we pass the first line.
e22ea7cc
RF
2959
2960 $start = $max if ($start <= 0);
69893cff
RGS
2961
2962 # Quit if we get back where we started,
e22ea7cc 2963 last if ($start == $end);
69893cff
RGS
2964
2965 # Match?
e22ea7cc
RF
2966 if ($dbline[$start] =~ m' . "\a$pat\a" . 'i) {
2967 if ($slave_editor) {
69893cff 2968 # Yep, follow slave editor requirements.
e22ea7cc
RF
2969 print $OUT "\032\032$filename:$start:0\n";
2970 }
2971 else {
69893cff 2972 # Yep, just print normally.
e22ea7cc
RF
2973 print $OUT "$start:\t",$dbline[$start],"\n";
2974 }
69893cff
RGS
2975
2976 # Found, so done.
e22ea7cc
RF
2977 last;
2978 }
2979 } ';
2980
2981 # Say we failed if the loop never found anything,
2982 print $OUT "?$pat?: not found\n" if ( $start == $end );
2983 next CMD;
2984 };
69893cff
RGS
2985
2986=head4 C<$rc> - Recall command
2987
2988Manages the commands in C<@hist> (which is created if C<Term::ReadLine> reports
2989that the terminal supports history). It find the the command required, puts it
2990into C<$cmd>, and redoes the loop to execute it.
2991
2992=cut
2993
e22ea7cc
RF
2994 # $rc - recall command.
2995 $cmd =~ /^$rc+\s*(-)?(\d+)?$/ && do {
69893cff
RGS
2996
2997 # No arguments, take one thing off history.
e22ea7cc 2998 pop(@hist) if length($cmd) > 1;
69893cff 2999
e22ea7cc 3000 # Relative (- found)?
69893cff 3001 # Y - index back from most recent (by 1 if bare minus)
e22ea7cc 3002 # N - go to that particular command slot or the last
69893cff 3003 # thing if nothing following.
e22ea7cc 3004 $i = $1 ? ( $#hist - ( $2 || 1 ) ) : ( $2 || $#hist );
69893cff
RGS
3005
3006 # Pick out the command desired.
e22ea7cc 3007 $cmd = $hist[$i];
69893cff
RGS
3008
3009 # Print the command to be executed and restart the loop
3010 # with that command in the buffer.
e22ea7cc
RF
3011 print $OUT $cmd, "\n";
3012 redo CMD;
3013 };
69893cff
RGS
3014
3015=head4 C<$sh$sh> - C<system()> command
3016
3017Calls the C<DB::system()> to handle the command. This keeps the C<STDIN> and
3018C<STDOUT> from getting messed up.
3019
3020=cut
3021
3022 # $sh$sh - run a shell command (if it's all ASCII).
3023 # Can't run shell commands with Unicode in the debugger, hmm.
e22ea7cc
RF
3024 $cmd =~ /^$sh$sh\s*([\x00-\xff]*)/ && do {
3025
69893cff 3026 # System it.
e22ea7cc
RF
3027 &system($1);
3028 next CMD;
3029 };
69893cff
RGS
3030
3031=head4 C<$rc I<pattern> $rc> - Search command history
3032
3033Another command to manipulate C<@hist>: this one searches it with a pattern.
be9a9b1d 3034If a command is found, it is placed in C<$cmd> and executed via C<redo>.
69893cff
RGS
3035
3036=cut
3037
e22ea7cc
RF
3038 # $rc pattern $rc - find a command in the history.
3039 $cmd =~ /^$rc([^$rc].*)$/ && do {
3040
69893cff 3041 # Create the pattern to use.
e22ea7cc 3042 $pat = "^$1";
69893cff
RGS
3043
3044 # Toss off last entry if length is >1 (and it always is).
e22ea7cc 3045 pop(@hist) if length($cmd) > 1;
69893cff
RGS
3046
3047 # Look backward through the history.
e22ea7cc
RF
3048 for ( $i = $#hist ; $i ; --$i ) {
3049
69893cff 3050 # Stop if we find it.
e22ea7cc
RF
3051 last if $hist[$i] =~ /$pat/;
3052 }
3053
3054 if ( !$i ) {
69893cff 3055
69893cff 3056 # Never found it.
e22ea7cc
RF
3057 print $OUT "No such command!\n\n";
3058 next CMD;
3059 }
69893cff
RGS
3060
3061 # Found it. Put it in the buffer, print it, and process it.
e22ea7cc
RF
3062 $cmd = $hist[$i];
3063 print $OUT $cmd, "\n";
3064 redo CMD;
3065 };
69893cff
RGS
3066
3067=head4 C<$sh> - Invoke a shell
3068
3069Uses C<DB::system> to invoke a shell.
3070
3071=cut
3072
3073 # $sh - start a shell.
e22ea7cc
RF
3074 $cmd =~ /^$sh$/ && do {
3075
69893cff
RGS
3076 # Run the user's shell. If none defined, run Bourne.
3077 # We resume execution when the shell terminates.
e22ea7cc
RF
3078 &system( $ENV{SHELL} || "/bin/sh" );
3079 next CMD;
3080 };
69893cff
RGS
3081
3082=head4 C<$sh I<command>> - Force execution of a command in a shell
3083
3084Like the above, but the command is passed to the shell. Again, we use
3085C<DB::system> to avoid problems with C<STDIN> and C<STDOUT>.
3086
3087=cut
3088
3089 # $sh command - start a shell and run a command in it.
e22ea7cc
RF
3090 $cmd =~ /^$sh\s*([\x00-\xff]*)/ && do {
3091
3092 # XXX: using csh or tcsh destroys sigint retvals!
3093 #&system($1); # use this instead
69893cff
RGS
3094
3095 # use the user's shell, or Bourne if none defined.
e22ea7cc
RF
3096 &system( $ENV{SHELL} || "/bin/sh", "-c", $1 );
3097 next CMD;
3098 };
69893cff
RGS
3099
3100=head4 C<H> - display commands in history
3101
3102Prints the contents of C<@hist> (if any).
3103
3104=cut
3105
7fddc82f
RF
3106 $cmd =~ /^H\b\s*\*/ && do {
3107 @hist = @truehist = ();
3108 print $OUT "History cleansed\n";
3109 next CMD;
3110 };
e22ea7cc
RF
3111
3112 $cmd =~ /^H\b\s*(-(\d+))?/ && do {
3113
3114 # Anything other than negative numbers is ignored by
69893cff 3115 # the (incorrect) pattern, so this test does nothing.
e22ea7cc 3116 $end = $2 ? ( $#hist - $2 ) : 0;
69893cff
RGS
3117
3118 # Set to the minimum if less than zero.
e22ea7cc 3119 $hist = 0 if $hist < 0;
69893cff 3120
e22ea7cc 3121 # Start at the end of the array.
69893cff
RGS
3122 # Stay in while we're still above the ending value.
3123 # Tick back by one each time around the loop.
e22ea7cc 3124 for ( $i = $#hist ; $i > $end ; $i-- ) {
69893cff
RGS
3125
3126 # Print the command unless it has no arguments.
e22ea7cc
RF
3127 print $OUT "$i: ", $hist[$i], "\n"
3128 unless $hist[$i] =~ /^.?$/;
3129 }
3130 next CMD;
3131 };
69893cff
RGS
3132
3133=head4 C<man, doc, perldoc> - look up documentation
3134
3135Just calls C<runman()> to print the appropriate document.
3136
3137=cut
3138
e22ea7cc
RF
3139 # man, perldoc, doc - show manual pages.
3140 $cmd =~ /^(?:man|(?:perl)?doc)\b(?:\s+([^(]*))?$/ && do {
3141 runman($1);
3142 next CMD;
3143 };
69893cff
RGS
3144
3145=head4 C<p> - print
3146
3147Builds a C<print EXPR> expression in the C<$cmd>; this will get executed at
3148the bottom of the loop.
3149
3150=cut
3151
3152 # p - print (no args): print $_.
e22ea7cc 3153 $cmd =~ s/^p$/print {\$DB::OUT} \$_/;
69893cff
RGS
3154
3155 # p - print the given expression.
e22ea7cc 3156 $cmd =~ s/^p\b/print {\$DB::OUT} /;
69893cff
RGS
3157
3158=head4 C<=> - define command alias
3159
3160Manipulates C<%alias> to add or list command aliases.
3161
3162=cut
3163
e22ea7cc
RF
3164 # = - set up a command alias.
3165 $cmd =~ s/^=\s*// && do {
3166 my @keys;
3167 if ( length $cmd == 0 ) {
3168
69893cff 3169 # No args, get current aliases.
e22ea7cc
RF
3170 @keys = sort keys %alias;
3171 }
3172 elsif ( my ( $k, $v ) = ( $cmd =~ /^(\S+)\s+(\S.*)/ ) ) {
3173
69893cff
RGS
3174 # Creating a new alias. $k is alias name, $v is
3175 # alias value.
3176
e22ea7cc
RF
3177 # can't use $_ or kill //g state
3178 for my $x ( $k, $v ) {
3179
3180 # Escape "alarm" characters.
3181 $x =~ s/\a/\\a/g;
3182 }
69893cff
RGS
3183
3184 # Substitute key for value, using alarm chars
e22ea7cc 3185 # as separators (which is why we escaped them in
69893cff 3186 # the command).
e22ea7cc 3187 $alias{$k} = "s\a$k\a$v\a";
69893cff
RGS
3188
3189 # Turn off standard warn and die behavior.
e22ea7cc
RF
3190 local $SIG{__DIE__};
3191 local $SIG{__WARN__};
69893cff
RGS
3192
3193 # Is it valid Perl?
e22ea7cc
RF
3194 unless ( eval "sub { s\a$k\a$v\a }; 1" ) {
3195
69893cff 3196 # Nope. Bad alias. Say so and get out.
e22ea7cc
RF
3197 print $OUT "Can't alias $k to $v: $@\n";
3198 delete $alias{$k};
3199 next CMD;
3200 }
3201
69893cff 3202 # We'll only list the new one.
e22ea7cc 3203 @keys = ($k);
69893cff
RGS
3204 } ## end elsif (my ($k, $v) = ($cmd...
3205
3206 # The argument is the alias to list.
e22ea7cc
RF
3207 else {
3208 @keys = ($cmd);
3209 }
69893cff
RGS
3210
3211 # List aliases.
e22ea7cc
RF
3212 for my $k (@keys) {
3213
69893cff
RGS
3214 # Messy metaquoting: Trim the substiution code off.
3215 # We use control-G as the delimiter because it's not
3216 # likely to appear in the alias.
e22ea7cc
RF
3217 if ( ( my $v = $alias{$k} ) =~ s\as\a$k\a(.*)\a$\a1\a ) {
3218
69893cff 3219 # Print the alias.
e22ea7cc
RF
3220 print $OUT "$k\t= $1\n";
3221 }
3222 elsif ( defined $alias{$k} ) {
3223
69893cff 3224 # Couldn't trim it off; just print the alias code.
e22ea7cc
RF
3225 print $OUT "$k\t$alias{$k}\n";
3226 }
3227 else {
3228
69893cff 3229 # No such, dude.
e22ea7cc
RF
3230 print "No alias for $k\n";
3231 }
69893cff 3232 } ## end for my $k (@keys)
e22ea7cc
RF
3233 next CMD;
3234 };
69893cff
RGS
3235
3236=head4 C<source> - read commands from a file.
3237
3238Opens a lexical filehandle and stacks it on C<@cmdfhs>; C<DB::readline> will
3239pick it up.
3240
3241=cut
3242
e22ea7cc
RF
3243 # source - read commands from a file (or pipe!) and execute.
3244 $cmd =~ /^source\s+(.*\S)/ && do {
3245 if ( open my $fh, $1 ) {
3246
69893cff 3247 # Opened OK; stick it in the list of file handles.
e22ea7cc
RF
3248 push @cmdfhs, $fh;
3249 }
3250 else {
3251
3252 # Couldn't open it.
3253 &warn("Can't execute `$1': $!\n");
3254 }
3255 next CMD;
3256 };
69893cff
RGS
3257
3258=head4 C<save> - send current history to a file
3259
3260Takes the complete history, (not the shrunken version you see with C<H>),
3261and saves it to the given filename, so it can be replayed using C<source>.
3262
3263Note that all C<^(save|source)>'s are commented out with a view to minimise recursion.
3264
3265=cut
3266
3267 # save source - write commands to a file for later use
3268 $cmd =~ /^save\s*(.*)$/ && do {
e22ea7cc
RF
3269 my $file = $1 || '.perl5dbrc'; # default?
3270 if ( open my $fh, "> $file" ) {
3271
3272 # chomp to remove extraneous newlines from source'd files
3273 chomp( my @truelist =
3274 map { m/^\s*(save|source)/ ? "#$_" : $_ }
3275 @truehist );
3276 print $fh join( "\n", @truelist );
69893cff 3277 print "commands saved in $file\n";
e22ea7cc
RF
3278 }
3279 else {
69893cff
RGS
3280 &warn("Can't save debugger commands in '$1': $!\n");
3281 }
3282 next CMD;
3283 };
3284
7fddc82f
RF
3285=head4 C<R> - restart
3286
3287Restart the debugger session.
3288
3289=head4 C<rerun> - rerun the current session
3290
3291Return to any given position in the B<true>-history list
3292
3293=cut
3294
3295 # R - restart execution.
3296 # rerun - controlled restart execution.
3297 $cmd =~ /^(R|rerun\s*(.*))$/ && do {
3298 my @args = ($1 eq 'R' ? restart() : rerun($2));
3299
ca28b541
AP
3300 # Close all non-system fds for a clean restart. A more
3301 # correct method would be to close all fds that were not
3302 # open when the process started, but this seems to be
3303 # hard. See "debugger 'R'estart and open database
3304 # connections" on p5p.
3305
47d3bbda 3306 my $max_fd = 1024; # default if POSIX can't be loaded
ca28b541
AP
3307 if (eval { require POSIX }) {
3308 $max_fd = POSIX::sysconf(POSIX::_SC_OPEN_MAX());
3309 }
3310
3311 if (defined $max_fd) {
3312 foreach ($^F+1 .. $max_fd-1) {
3313 next unless open FD_TO_CLOSE, "<&=$_";
3314 close(FD_TO_CLOSE);
3315 }
3316 }
3317
7fddc82f
RF
3318 # And run Perl again. We use exec() to keep the
3319 # PID stable (and that way $ini_pids is still valid).
3320 exec(@args) || print $OUT "exec failed: $!\n";
3321
3322 last CMD;
3323 };
3324
69893cff
RGS
3325=head4 C<|, ||> - pipe output through the pager.
3326
be9a9b1d 3327For C<|>, we save C<OUT> (the debugger's output filehandle) and C<STDOUT>
69893cff
RGS
3328(the program's standard output). For C<||>, we only save C<OUT>. We open a
3329pipe to the pager (restoring the output filehandles if this fails). If this
3330is the C<|> command, we also set up a C<SIGPIPE> handler which will simply
3331set C<$signal>, sending us back into the debugger.
3332
3333We then trim off the pipe symbols and C<redo> the command loop at the
3334C<PIPE> label, causing us to evaluate the command in C<$cmd> without
3335reading another.
3336
3337=cut
3338
3339 # || - run command in the pager, with output to DB::OUT.
e22ea7cc
RF
3340 $cmd =~ /^\|\|?\s*[^|]/ && do {
3341 if ( $pager =~ /^\|/ ) {
3342
69893cff 3343 # Default pager is into a pipe. Redirect I/O.
e22ea7cc
RF
3344 open( SAVEOUT, ">&STDOUT" )
3345 || &warn("Can't save STDOUT");
3346 open( STDOUT, ">&OUT" )
3347 || &warn("Can't redirect STDOUT");
69893cff 3348 } ## end if ($pager =~ /^\|/)
e22ea7cc
RF
3349 else {
3350
69893cff 3351 # Not into a pipe. STDOUT is safe.
e22ea7cc
RF
3352 open( SAVEOUT, ">&OUT" ) || &warn("Can't save DB::OUT");
3353 }
69893cff
RGS
3354
3355 # Fix up environment to record we have less if so.
e22ea7cc
RF
3356 fix_less();
3357
3358 unless ( $piped = open( OUT, $pager ) ) {
69893cff 3359
69893cff 3360 # Couldn't open pipe to pager.
e22ea7cc
RF
3361 &warn("Can't pipe output to `$pager'");
3362 if ( $pager =~ /^\|/ ) {
3363
69893cff 3364 # Redirect I/O back again.
e22ea7cc
RF
3365 open( OUT, ">&STDOUT" ) # XXX: lost message
3366 || &warn("Can't restore DB::OUT");
3367 open( STDOUT, ">&SAVEOUT" )
3368 || &warn("Can't restore STDOUT");
3369 close(SAVEOUT);
69893cff 3370 } ## end if ($pager =~ /^\|/)
e22ea7cc
RF
3371 else {
3372
69893cff 3373 # Redirect I/O. STDOUT already safe.
e22ea7cc
RF
3374 open( OUT, ">&STDOUT" ) # XXX: lost message
3375 || &warn("Can't restore DB::OUT");
3376 }
3377 next CMD;
69893cff
RGS
3378 } ## end unless ($piped = open(OUT,...
3379
3380 # Set up broken-pipe handler if necessary.
e22ea7cc
RF
3381 $SIG{PIPE} = \&DB::catch
3382 if $pager =~ /^\|/
3383 && ( "" eq $SIG{PIPE} || "DEFAULT" eq $SIG{PIPE} );
69893cff
RGS
3384
3385 # Save current filehandle, unbuffer out, and put it back.
e22ea7cc
RF
3386 $selected = select(OUT);
3387 $| = 1;
69893cff
RGS
3388
3389 # Don't put it back if pager was a pipe.
e22ea7cc 3390 select($selected), $selected = "" unless $cmd =~ /^\|\|/;
69893cff
RGS
3391
3392 # Trim off the pipe symbols and run the command now.
e22ea7cc
RF
3393 $cmd =~ s/^\|+\s*//;
3394 redo PIPE;
3395 };
69893cff
RGS
3396
3397=head3 END OF COMMAND PARSING
3398
3399Anything left in C<$cmd> at this point is a Perl expression that we want to
3400evaluate. We'll always evaluate in the user's context, and fully qualify
3401any variables we might want to address in the C<DB> package.
3402
3403=cut
3404
3405 # t - turn trace on.
e22ea7cc 3406 $cmd =~ s/^t\s/\$DB::trace |= 1;\n/;
69893cff
RGS
3407
3408 # s - single-step. Remember the last command was 's'.
e22ea7cc 3409 $cmd =~ s/^s\s/\$DB::single = 1;\n/ && do { $laststep = 's' };
69893cff
RGS
3410
3411 # n - single-step, but not into subs. Remember last command
e22ea7cc
RF
3412 # was 'n'.
3413 $cmd =~ s/^n\s/\$DB::single = 2;\n/ && do { $laststep = 'n' };
69893cff 3414
e22ea7cc 3415 } # PIPE:
69893cff 3416
e22ea7cc 3417 # Make sure the flag that says "the debugger's running" is
69893cff 3418 # still on, to make sure we get control again.
e22ea7cc 3419 $evalarg = "\$^D = \$^D | \$DB::db_stop;\n$cmd";
69893cff
RGS
3420
3421 # Run *our* eval that executes in the caller's context.
e22ea7cc 3422 &eval;
69893cff
RGS
3423
3424 # Turn off the one-time-dump stuff now.
e22ea7cc
RF
3425 if ($onetimeDump) {
3426 $onetimeDump = undef;
69893cff 3427 $onetimedumpDepth = undef;
e22ea7cc
RF
3428 }
3429 elsif ( $term_pid == $$ ) {
c7e68384
IZ
3430 eval { # May run under miniperl, when not available...
3431 STDOUT->flush();
3432 STDERR->flush();
3433 };
e22ea7cc 3434
69893cff 3435 # XXX If this is the master pid, print a newline.
e22ea7cc
RF
3436 print $OUT "\n";
3437 }
3438 } ## end while (($term || &setterm...
69893cff
RGS
3439
3440=head3 POST-COMMAND PROCESSING
3441
3442After each command, we check to see if the command output was piped anywhere.
3443If so, we go through the necessary code to unhook the pipe and go back to
3444our standard filehandles for input and output.
3445
3446=cut
3447
e22ea7cc 3448 continue { # CMD:
69893cff
RGS
3449
3450 # At the end of every command:
e22ea7cc
RF
3451 if ($piped) {
3452
69893cff 3453 # Unhook the pipe mechanism now.
e22ea7cc
RF
3454 if ( $pager =~ /^\|/ ) {
3455
69893cff 3456 # No error from the child.
e22ea7cc 3457 $? = 0;
69893cff 3458
e22ea7cc
RF
3459 # we cannot warn here: the handle is missing --tchrist
3460 close(OUT) || print SAVEOUT "\nCan't close DB::OUT\n";
69893cff 3461
e22ea7cc 3462 # most of the $? crud was coping with broken cshisms
69893cff 3463 # $? is explicitly set to 0, so this never runs.
e22ea7cc
RF
3464 if ($?) {
3465 print SAVEOUT "Pager `$pager' failed: ";
3466 if ( $? == -1 ) {
3467 print SAVEOUT "shell returned -1\n";
3468 }
3469 elsif ( $? >> 8 ) {
3470 print SAVEOUT ( $? & 127 )
3471 ? " (SIG#" . ( $? & 127 ) . ")"
3472 : "", ( $? & 128 ) ? " -- core dumped" : "", "\n";
3473 }
3474 else {
3475 print SAVEOUT "status ", ( $? >> 8 ), "\n";
3476 }
69893cff
RGS
3477 } ## end if ($?)
3478
e22ea7cc 3479 # Reopen filehandle for our output (if we can) and
69893cff 3480 # restore STDOUT (if we can).
e22ea7cc
RF
3481 open( OUT, ">&STDOUT" ) || &warn("Can't restore DB::OUT");
3482 open( STDOUT, ">&SAVEOUT" )
3483 || &warn("Can't restore STDOUT");
69893cff
RGS
3484
3485 # Turn off pipe exception handler if necessary.
e22ea7cc 3486 $SIG{PIPE} = "DEFAULT" if $SIG{PIPE} eq \&DB::catch;
69893cff 3487
e22ea7cc
RF
3488 # Will stop ignoring SIGPIPE if done like nohup(1)
3489 # does SIGINT but Perl doesn't give us a choice.
69893cff 3490 } ## end if ($pager =~ /^\|/)
e22ea7cc
RF
3491 else {
3492
69893cff 3493 # Non-piped "pager". Just restore STDOUT.
e22ea7cc
RF
3494 open( OUT, ">&SAVEOUT" ) || &warn("Can't restore DB::OUT");
3495 }
69893cff
RGS
3496
3497 # Close filehandle pager was using, restore the normal one
3498 # if necessary,
3499 close(SAVEOUT);
e22ea7cc 3500 select($selected), $selected = "" unless $selected eq "";
69893cff
RGS
3501
3502 # No pipes now.
e22ea7cc 3503 $piped = "";
69893cff 3504 } ## end if ($piped)
e22ea7cc 3505 } # CMD:
69893cff
RGS
3506
3507=head3 COMMAND LOOP TERMINATION
3508
3509When commands have finished executing, we come here. If the user closed the
3510input filehandle, we turn on C<$fall_off_end> to emulate a C<q> command. We
3511evaluate any post-prompt items. We restore C<$@>, C<$!>, C<$^E>, C<$,>, C<$/>,
3512C<$\>, and C<$^W>, and return a null list as expected by the Perl interpreter.
3513The interpreter will then execute the next line and then return control to us
3514again.
3515
3516=cut
3517
3518 # No more commands? Quit.
e22ea7cc 3519 $fall_off_end = 1 unless defined $cmd; # Emulate `q' on EOF
69893cff
RGS
3520
3521 # Evaluate post-prompt commands.
e22ea7cc
RF
3522 foreach $evalarg (@$post) {
3523 &eval;
3524 }
3525 } # if ($single || $signal)
69893cff
RGS
3526
3527 # Put the user's globals back where you found them.
e22ea7cc 3528 ( $@, $!, $^E, $,, $/, $\, $^W ) = @saved;
69893cff
RGS
3529 ();
3530} ## end sub DB
3531
3532# The following code may be executed now:
3533# BEGIN {warn 4}
3534
3535=head2 sub
3536
3537C<sub> is called whenever a subroutine call happens in the program being
3538debugged. The variable C<$DB::sub> contains the name of the subroutine
3539being called.
3540
3541The core function of this subroutine is to actually call the sub in the proper
3542context, capturing its output. This of course causes C<DB::DB> to get called
3543again, repeating until the subroutine ends and returns control to C<DB::sub>
3544again. Once control returns, C<DB::sub> figures out whether or not to dump the
3545return value, and returns its captured copy of the return value as its own
3546return value. The value then feeds back into the program being debugged as if
3547C<DB::sub> hadn't been there at all.
3548
3549C<sub> does all the work of printing the subroutine entry and exit messages
3550enabled by setting C<$frame>. It notes what sub the autoloader got called for,
3551and also prints the return value if needed (for the C<r> command and if
3552the 16 bit is set in C<$frame>).
3553
3554It also tracks the subroutine call depth by saving the current setting of
3555C<$single> in the C<@stack> package global; if this exceeds the value in
3556C<$deep>, C<sub> automatically turns on printing of the current depth by
be9a9b1d 3557setting the C<4> bit in C<$single>. In any case, it keeps the current setting
69893cff
RGS
3558of stop/don't stop on entry to subs set as it currently is set.
3559
3560=head3 C<caller()> support
3561
3562If C<caller()> is called from the package C<DB>, it provides some
3563additional data, in the following order:
3564
3565=over 4
3566
3567=item * C<$package>
3568
3569The package name the sub was in
3570
3571=item * C<$filename>
3572
3573The filename it was defined in
3574
3575=item * C<$line>
3576
3577The line number it was defined on
3578
3579=item * C<$subroutine>
3580
be9a9b1d 3581The subroutine name; C<(eval)> if an C<eval>().
69893cff
RGS
3582
3583=item * C<$hasargs>
3584
35851 if it has arguments, 0 if not
3586
3587=item * C<$wantarray>
3588
35891 if array context, 0 if scalar context
3590
3591=item * C<$evaltext>
3592
3593The C<eval>() text, if any (undefined for C<eval BLOCK>)
3594
3595=item * C<$is_require>
3596
3597frame was created by a C<use> or C<require> statement
3598
3599=item * C<$hints>
3600
3601pragma information; subject to change between versions
3602
3603=item * C<$bitmask>
3604
be9a9b1d 3605pragma information; subject to change between versions
69893cff
RGS
3606
3607=item * C<@DB::args>
3608
3609arguments with which the subroutine was invoked
3610
3611=back
3612
3613=cut
d338d6fe 3614
d12a4851 3615sub sub {
69893cff 3616
2cbb2ee1
RGS
3617 # lock ourselves under threads
3618 lock($DBGR);
3619
69893cff
RGS
3620 # Whether or not the autoloader was running, a scalar to put the
3621 # sub's return value in (if needed), and an array to put the sub's
3622 # return value in (if needed).
e22ea7cc 3623 my ( $al, $ret, @ret ) = "";
2cbb2ee1
RGS
3624 if ($sub =~ /^threads::new$/ && $ENV{PERL5DB_THREADED}) {
3625 print "creating new thread\n";
3626 }
69893cff
RGS
3627
3628 # If the last ten characters are C'::AUTOLOAD', note we've traced
3629 # into AUTOLOAD for $sub.
e22ea7cc
RF
3630 if ( length($sub) > 10 && substr( $sub, -10, 10 ) eq '::AUTOLOAD' ) {
3631 $al = " for $$sub";
d12a4851 3632 }
69893cff
RGS
3633
3634 # We stack the stack pointer and then increment it to protect us
3635 # from a situation that might unwind a whole bunch of call frames
3636 # at once. Localizing the stack pointer means that it will automatically
3637 # unwind the same amount when multiple stack frames are unwound.
e22ea7cc 3638 local $stack_depth = $stack_depth + 1; # Protect from non-local exits
69893cff
RGS
3639
3640 # Expand @stack.
d12a4851 3641 $#stack = $stack_depth;
69893cff
RGS
3642
3643 # Save current single-step setting.
d12a4851 3644 $stack[-1] = $single;
69893cff 3645
e22ea7cc 3646 # Turn off all flags except single-stepping.
d12a4851 3647 $single &= 1;
69893cff
RGS
3648
3649 # If we've gotten really deeply recursed, turn on the flag that will
3650 # make us stop with the 'deep recursion' message.
d12a4851 3651 $single |= 4 if $stack_depth == $deep;
69893cff
RGS
3652
3653 # If frame messages are on ...
3654 (
3655 $frame & 4 # Extended frame entry message
e22ea7cc
RF
3656 ? (
3657 print_lineinfo( ' ' x ( $stack_depth - 1 ), "in " ),
69893cff 3658
e22ea7cc 3659 # Why -1? But it works! :-(
69893cff
RGS
3660 # Because print_trace will call add 1 to it and then call
3661 # dump_trace; this results in our skipping -1+1 = 0 stack frames
3662 # in dump_trace.
e22ea7cc
RF
3663 print_trace( $LINEINFO, -1, 1, 1, "$sub$al" )
3664 )
3665 : print_lineinfo( ' ' x ( $stack_depth - 1 ), "entering $sub$al\n" )
3666
69893cff 3667 # standard frame entry message
e22ea7cc
RF
3668 )
3669 if $frame;
69893cff
RGS
3670
3671 # Determine the sub's return type,and capture approppriately.
d12a4851 3672 if (wantarray) {
e22ea7cc 3673
69893cff
RGS
3674 # Called in array context. call sub and capture output.
3675 # DB::DB will recursively get control again if appropriate; we'll come
3676 # back here when the sub is finished.
d12a4851 3677 if ($assertion) {
e22ea7cc
RF
3678 $assertion = 0;
3679 eval { @ret = &$sub; };
3680 if ($@) {
3681 print $OUT $@;
3682 $signal = 1 unless $warnassertions;
3683 }
3684 }
3685 else {
69893cff 3686 @ret = &$sub;
69893cff 3687 }
69893cff
RGS
3688
3689 # Pop the single-step value back off the stack.
e22ea7cc 3690 $single |= $stack[ $stack_depth-- ];
69893cff
RGS
3691
3692 # Check for exit trace messages...
e22ea7cc
RF
3693 (
3694 $frame & 4 # Extended exit message
3695 ? (
3696 print_lineinfo( ' ' x $stack_depth, "out " ),
3697 print_trace( $LINEINFO, -1, 1, 1, "$sub$al" )
3698 )
3699 : print_lineinfo( ' ' x $stack_depth, "exited $sub$al\n" )
3700
69893cff 3701 # Standard exit message
e22ea7cc
RF
3702 )
3703 if $frame & 2;
69893cff
RGS
3704
3705 # Print the return info if we need to.
e22ea7cc
RF
3706 if ( $doret eq $stack_depth or $frame & 16 ) {
3707
69893cff 3708 # Turn off output record separator.
e22ea7cc
RF