This is a live mirror of the Perl 5 development currently hosted at https://github.com/perl/perl5
Extract _restore_shared_globals_after_restart.
[perl5.git] / lib / perl5db.pl
CommitLineData
e22ea7cc 1
b570d64b 2=head1 NAME
69893cff 3
be9a9b1d 4perl5db.pl - the perl debugger
69893cff
RGS
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
b570d64b 25features was done using global variables, globs and the C<local()> operator
69893cff
RGS
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
b570d64b 37debugger itself.
69893cff
RGS
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
69893cff
RGS
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
b570d64b 49As you may recall from reading C<perlfunc>, the C<local()> operator makes a
69893cff 50temporary copy of a variable in the current scope. When the scope ends, the
b570d64b 51old copy is restored. This is often used in the debugger to handle the
69893cff
RGS
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,
b570d64b 62then altered. When the subroutine returns, Perl automatically undoes the
69893cff
RGS
63localization, restoring the previous value. Voila, automatic stack management.
64
b570d64b 65The debugger uses this trick a I<lot>. Of particular note is C<DB::eval>,
69893cff
RGS
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
b570d64b 69value of C<$@> is restored. This makes it simple (well, I<simpler>) to keep
69893cff
RGS
70track of C<$@> 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
b570d64b 76This is used to cleverly reverse the sense of a logical test depending on
69893cff 77the value of an auxiliary variable. For instance, the debugger's C<S>
b570d64b 78(search for subroutines by pattern) allows you to negate the pattern
69893cff
RGS
79like this:
80
81 # Find all non-'foo' subs:
b570d64b 82 S !/foo/
69893cff
RGS
83
84Boolean algebra states that the truth table for XOR looks like this:
85
86=over 4
87
b570d64b 88=item * 0 ^ 0 = 0
69893cff
RGS
89
90(! not present and no match) --> false, don't print
91
b570d64b 92=item * 0 ^ 1 = 1
69893cff
RGS
93
94(! not present and matches) --> true, print
95
b570d64b 96=item * 1 ^ 0 = 1
69893cff
RGS
97
98(! present and no match) --> true, print
99
b570d64b 100=item * 1 ^ 1 = 0
69893cff
RGS
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
b570d64b 108compact a more complicated if-then-elseif-else into a more elegant
69893cff
RGS
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<$frame>, have I<magical> values composed
69893cff 116of 1, 2, 4, etc. (powers of 2) OR'ed together. This allows several pieces
b570d64b 117of state to be stored independently in a single scalar.
69893cff
RGS
118
119A test like
120
121 if ($scalar & 4) ...
122
b570d64b 123is checking to see if the appropriate bit is on. Since each bit can be
69893cff 124"addressed" independently in this way, C<$scalar> is acting sort of like
b570d64b 125an array of bits. Obviously, since the contents of C<$scalar> are just a
69893cff
RGS
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
b570d64b 130all over your program whenever a bit is set, cleared, or checked. So why do
69893cff
RGS
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
b570d64b 140this over-optimization at the expense of readability? Possibly, but the
69893cff
RGS
141debugger accesses these variables a I<lot>. Any rewrite of the code will
142probably have to benchmark alternate implementations and see which is the
b570d64b 143best balance of readability and speed, and then document how it actually
69893cff
RGS
144works.
145
be9a9b1d
AT
146=item *
147
b570d64b 148Second, it's very easy to serialize a scalar number. This is done in
69893cff
RGS
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
b570d64b 151this trivial.
69893cff 152
be9a9b1d
AT
153=item *
154
b570d64b
SF
155Third, some of these variables are being shared with the Perl core
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
69893cff
RGS
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
b570d64b 165speculative - it's not exactly clear what a given variable or chunk of
69893cff
RGS
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
b570d64b 171=head1 DATA STRUCTURES MAINTAINED BY CORE
69893cff
RGS
172
173There are a number of special data structures provided to the debugger by
174the Perl interpreter.
175
7e17a74c
JJ
176The array C<@{$main::{'_<'.$filename}}> (aliased locally to C<@dbline>
177via glob assignment) contains the text from C<$filename>, with each
178element corresponding to a single line of C<$filename>. Additionally,
179breakable lines will be dualvars with the numeric component being the
180memory address of a COP node. Non-breakable lines are dualvar to 0.
69893cff 181
b570d64b
SF
182The hash C<%{'_<'.$filename}> (aliased locally to C<%dbline> via glob
183assignment) contains breakpoints and actions. The keys are line numbers;
184you can set individual values, but not the whole hash. The Perl interpreter
69893cff 185uses this hash to determine where breakpoints have been set. Any true value is
be9a9b1d 186considered to be a breakpoint; C<perl5db.pl> uses C<$break_condition\0$action>.
69893cff
RGS
187Values are magical in numeric context: 1 if the line is breakable, 0 if not.
188
ef18ae63 189The scalar C<${"_<$filename"}> simply contains the string C<<< _<$filename> >>>.
be9a9b1d
AT
190This is also the case for evaluated strings that contain subroutines, or
191which are currently being executed. The $filename for C<eval>ed strings looks
d24ca0c5 192like C<(eval 34).
69893cff
RGS
193
194=head1 DEBUGGER STARTUP
195
196When C<perl5db.pl> starts, it reads an rcfile (C<perl5db.ini> for
197non-interactive sessions, C<.perldb> for interactive ones) that can set a number
198of options. In addition, this file may define a subroutine C<&afterinit>
b570d64b 199that will be executed (in the debugger's context) after the debugger has
69893cff
RGS
200initialized itself.
201
b570d64b 202Next, it checks the C<PERLDB_OPTS> environment variable and treats its
be9a9b1d 203contents as the argument of a C<o> command in the debugger.
69893cff
RGS
204
205=head2 STARTUP-ONLY OPTIONS
206
207The following options can only be specified at startup.
208To set them in your rcfile, add a call to
209C<&parse_options("optionName=new_value")>.
210
211=over 4
212
b570d64b 213=item * TTY
69893cff
RGS
214
215the TTY to use for debugging i/o.
216
b570d64b 217=item * noTTY
69893cff
RGS
218
219if set, goes in NonStop mode. On interrupt, if TTY is not set,
b0e77abc 220uses the value of noTTY or F<$HOME/.perldbtty$$> to find TTY using
69893cff
RGS
221Term::Rendezvous. Current variant is to have the name of TTY in this
222file.
223
b570d64b 224=item * ReadLine
69893cff 225
5561b870 226if false, a dummy ReadLine is used, so you can debug
69893cff
RGS
227ReadLine applications.
228
b570d64b 229=item * NonStop
69893cff
RGS
230
231if true, no i/o is performed until interrupt.
232
b570d64b 233=item * LineInfo
69893cff
RGS
234
235file or pipe to print line number info to. If it is a
236pipe, a short "emacs like" message is used.
237
b570d64b 238=item * RemotePort
69893cff
RGS
239
240host:port to connect to on remote host for remote debugging.
241
5561b870
AK
242=item * HistFile
243
244file to store session history to. There is no default and so no
245history file is written unless this variable is explicitly set.
246
247=item * HistSize
248
249number of commands to store to the file specified in C<HistFile>.
250Default is 100.
251
69893cff
RGS
252=back
253
254=head3 SAMPLE RCFILE
255
256 &parse_options("NonStop=1 LineInfo=db.out");
257 sub afterinit { $trace = 1; }
258
259The script will run without human intervention, putting trace
260information into C<db.out>. (If you interrupt it, you had better
be9a9b1d 261reset C<LineInfo> to something I<interactive>!)
69893cff
RGS
262
263=head1 INTERNALS DESCRIPTION
264
265=head2 DEBUGGER INTERFACE VARIABLES
266
267Perl supplies the values for C<%sub>. It effectively inserts
be9a9b1d 268a C<&DB::DB();> in front of each place that can have a
69893cff
RGS
269breakpoint. At each subroutine call, it calls C<&DB::sub> with
270C<$DB::sub> set to the called subroutine. It also inserts a C<BEGIN
271{require 'perl5db.pl'}> before the first line.
272
273After each C<require>d file is compiled, but before it is executed, a
274call to C<&DB::postponed($main::{'_<'.$filename})> is done. C<$filename>
275is the expanded name of the C<require>d file (as found via C<%INC>).
276
277=head3 IMPORTANT INTERNAL VARIABLES
278
279=head4 C<$CreateTTY>
280
281Used to control when the debugger will attempt to acquire another TTY to be
b570d64b 282used for input.
69893cff 283
b570d64b 284=over
69893cff
RGS
285
286=item * 1 - on C<fork()>
287
288=item * 2 - debugger is started inside debugger
289
290=item * 4 - on startup
291
292=back
293
294=head4 C<$doret>
295
296The value -2 indicates that no return value should be printed.
297Any other positive value causes C<DB::sub> to print return values.
298
299=head4 C<$evalarg>
300
301The item to be eval'ed by C<DB::eval>. Used to prevent messing with the current
302contents of C<@_> when C<DB::eval> is called.
303
304=head4 C<$frame>
305
306Determines what messages (if any) will get printed when a subroutine (or eval)
b570d64b 307is entered or exited.
69893cff
RGS
308
309=over 4
310
311=item * 0 - No enter/exit messages
312
be9a9b1d 313=item * 1 - Print I<entering> messages on subroutine entry
69893cff
RGS
314
315=item * 2 - Adds exit messages on subroutine exit. If no other flag is on, acts like 1+2.
316
be9a9b1d 317=item * 4 - Extended messages: C<< <in|out> I<context>=I<fully-qualified sub name> from I<file>:I<line> >>. If no other flag is on, acts like 1+4.
69893cff
RGS
318
319=item * 8 - Adds parameter information to messages, and overloaded stringify and tied FETCH is enabled on the printed arguments. Ignored if C<4> is not on.
320
321=item * 16 - Adds C<I<context> return from I<subname>: I<value>> messages on subroutine/eval exit. Ignored if C<4> is is not on.
322
323=back
324
be9a9b1d 325To get everything, use C<$frame=30> (or C<o f=30> as a debugger command).
69893cff
RGS
326The debugger internally juggles the value of C<$frame> during execution to
327protect external modules that the debugger uses from getting traced.
328
329=head4 C<$level>
330
b570d64b
SF
331Tracks current debugger nesting level. Used to figure out how many
332C<E<lt>E<gt>> pairs to surround the line number with when the debugger
69893cff
RGS
333outputs a prompt. Also used to help determine if the program has finished
334during command parsing.
335
336=head4 C<$onetimeDump>
337
338Controls what (if anything) C<DB::eval()> will print after evaluating an
339expression.
340
341=over 4
342
343=item * C<undef> - don't print anything
344
345=item * C<dump> - use C<dumpvar.pl> to display the value returned
346
347=item * C<methods> - print the methods callable on the first item returned
348
349=back
350
351=head4 C<$onetimeDumpDepth>
352
be9a9b1d 353Controls how far down C<dumpvar.pl> will go before printing C<...> while
69893cff
RGS
354dumping a structure. Numeric. If C<undef>, print all levels.
355
356=head4 C<$signal>
357
358Used to track whether or not an C<INT> signal has been detected. C<DB::DB()>,
359which is called before every statement, checks this and puts the user into
360command mode if it finds C<$signal> set to a true value.
361
362=head4 C<$single>
363
364Controls behavior during single-stepping. Stacked in C<@stack> on entry to
365each subroutine; popped again at the end of each subroutine.
366
b570d64b 367=over 4
69893cff
RGS
368
369=item * 0 - run continuously.
370
be9a9b1d 371=item * 1 - single-step, go into subs. The C<s> command.
69893cff 372
be9a9b1d 373=item * 2 - single-step, don't go into subs. The C<n> command.
69893cff 374
be9a9b1d
AT
375=item * 4 - print current sub depth (turned on to force this when C<too much
376recursion> occurs.
69893cff
RGS
377
378=back
379
380=head4 C<$trace>
381
b570d64b 382Controls the output of trace information.
69893cff
RGS
383
384=over 4
385
386=item * 1 - The C<t> command was entered to turn on tracing (every line executed is printed)
387
388=item * 2 - watch expressions are active
389
390=item * 4 - user defined a C<watchfunction()> in C<afterinit()>
391
392=back
393
394=head4 C<$slave_editor>
395
3961 if C<LINEINFO> was directed to a pipe; 0 otherwise.
397
398=head4 C<@cmdfhs>
399
400Stack of filehandles that C<DB::readline()> will read commands from.
401Manipulated by the debugger's C<source> command and C<DB::readline()> itself.
402
403=head4 C<@dbline>
404
b570d64b 405Local alias to the magical line array, C<@{$main::{'_<'.$filename}}> ,
69893cff
RGS
406supplied by the Perl interpreter to the debugger. Contains the source.
407
408=head4 C<@old_watch>
409
410Previous values of watch expressions. First set when the expression is
411entered; reset whenever the watch expression changes.
412
413=head4 C<@saved>
414
415Saves important globals (C<$@>, C<$!>, C<$^E>, C<$,>, C<$/>, C<$\>, C<$^W>)
416so that the debugger can substitute safe values while it's running, and
417restore them when it returns control.
418
419=head4 C<@stack>
420
421Saves the current value of C<$single> on entry to a subroutine.
422Manipulated by the C<c> command to turn off tracing in all subs above the
423current one.
424
425=head4 C<@to_watch>
426
427The 'watch' expressions: to be evaluated before each line is executed.
428
429=head4 C<@typeahead>
430
431The typeahead buffer, used by C<DB::readline>.
432
433=head4 C<%alias>
434
435Command aliases. Stored as character strings to be substituted for a command
436entered.
437
438=head4 C<%break_on_load>
439
440Keys are file names, values are 1 (break when this file is loaded) or undef
441(don't break when it is loaded).
442
443=head4 C<%dbline>
444
be9a9b1d 445Keys are line numbers, values are C<condition\0action>. If used in numeric
69893cff
RGS
446context, values are 0 if not breakable, 1 if breakable, no matter what is
447in the actual hash entry.
448
449=head4 C<%had_breakpoints>
450
451Keys are file names; values are bitfields:
452
b570d64b 453=over 4
69893cff
RGS
454
455=item * 1 - file has a breakpoint in it.
456
457=item * 2 - file has an action in it.
458
459=back
460
461A zero or undefined value means this file has neither.
462
463=head4 C<%option>
464
465Stores the debugger options. These are character string values.
466
467=head4 C<%postponed>
468
469Saves breakpoints for code that hasn't been compiled yet.
470Keys are subroutine names, values are:
471
472=over 4
473
be9a9b1d 474=item * C<compile> - break when this sub is compiled
69893cff 475
be9a9b1d 476=item * C<< break +0 if <condition> >> - break (conditionally) at the start of this routine. The condition will be '1' if no condition was specified.
69893cff
RGS
477
478=back
479
480=head4 C<%postponed_file>
481
482This hash keeps track of breakpoints that need to be set for files that have
483not yet been compiled. Keys are filenames; values are references to hashes.
484Each of these hashes is keyed by line number, and its values are breakpoint
be9a9b1d 485definitions (C<condition\0action>).
69893cff
RGS
486
487=head1 DEBUGGER INITIALIZATION
488
489The debugger's initialization actually jumps all over the place inside this
b570d64b
SF
490package. This is because there are several BEGIN blocks (which of course
491execute immediately) spread through the code. Why is that?
69893cff 492
b570d64b 493The debugger needs to be able to change some things and set some things up
69893cff
RGS
494before the debugger code is compiled; most notably, the C<$deep> variable that
495C<DB::sub> uses to tell when a program has recursed deeply. In addition, the
496debugger has to turn off warnings while the debugger code is compiled, but then
497restore them to their original setting before the program being debugged begins
498executing.
499
500The first C<BEGIN> block simply turns off warnings by saving the current
501setting of C<$^W> and then setting it to zero. The second one initializes
502the debugger variables that are needed before the debugger begins executing.
b570d64b 503The third one puts C<$^X> back to its former value.
69893cff
RGS
504
505We'll detail the second C<BEGIN> block later; just remember that if you need
506to initialize something before the debugger starts really executing, that's
507where it has to go.
508
509=cut
510
a687059c
LW
511package DB;
512
6b24a4b7
SF
513use strict;
514
c7e68384 515BEGIN {eval 'use IO::Handle'}; # Needed for flush only? breaks under miniperl
9eba6a4e 516
e56c1e8d
SF
517BEGIN {
518 require feature;
519 $^V =~ /^v(\d+\.\d+)/;
520 feature->import(":$1");
521}
522
54d04a52 523# Debugger for Perl 5.00x; perl5db.pl patch level:
6b24a4b7
SF
524use vars qw($VERSION $header);
525
b5afd346 526$VERSION = '1.39_04';
69893cff 527
e22ea7cc 528$header = "perl5db.pl version $VERSION";
d338d6fe 529
69893cff
RGS
530=head1 DEBUGGER ROUTINES
531
532=head2 C<DB::eval()>
533
534This function replaces straight C<eval()> inside the debugger; it simplifies
535the process of evaluating code in the user's context.
536
b570d64b 537The code to be evaluated is passed via the package global variable
69893cff
RGS
538C<$DB::evalarg>; this is done to avoid fiddling with the contents of C<@_>.
539
be9a9b1d
AT
540Before we do the C<eval()>, we preserve the current settings of C<$trace>,
541C<$single>, C<$^D> and C<$usercontext>. The latter contains the
542preserved values of C<$@>, C<$!>, C<$^E>, C<$,>, C<$/>, C<$\>, C<$^W> and the
543user's current package, grabbed when C<DB::DB> got control. This causes the
544proper context to be used when the eval is actually done. Afterward, we
545restore C<$trace>, C<$single>, and C<$^D>.
69893cff
RGS
546
547Next we need to handle C<$@> without getting confused. We save C<$@> in a
b570d64b
SF
548local lexical, localize C<$saved[0]> (which is where C<save()> will put
549C<$@>), and then call C<save()> to capture C<$@>, C<$!>, C<$^E>, C<$,>,
69893cff 550C<$/>, C<$\>, and C<$^W>) and set C<$,>, C<$/>, C<$\>, and C<$^W> to values
b570d64b
SF
551considered sane by the debugger. If there was an C<eval()> error, we print
552it on the debugger's output. If C<$onetimedump> is defined, we call
553C<dumpit> if it's set to 'dump', or C<methods> if it's set to
554'methods'. Setting it to something else causes the debugger to do the eval
555but not print the result - handy if you want to do something else with it
69893cff
RGS
556(the "watch expressions" code does this to get the value of the watch
557expression but not show it unless it matters).
558
b570d64b
SF
559In any case, we then return the list of output from C<eval> to the caller,
560and unwinding restores the former version of C<$@> in C<@saved> as well
69893cff
RGS
561(the localization of C<$saved[0]> goes away at the end of this scope).
562
563=head3 Parameters and variables influencing execution of DB::eval()
564
565C<DB::eval> isn't parameterized in the standard way; this is to keep the
566debugger's calls to C<DB::eval()> from mucking with C<@_>, among other things.
b570d64b 567The variables listed below influence C<DB::eval()>'s execution directly.
69893cff
RGS
568
569=over 4
570
571=item C<$evalarg> - the thing to actually be eval'ed
572
be9a9b1d 573=item C<$trace> - Current state of execution tracing
69893cff 574
be9a9b1d 575=item C<$single> - Current state of single-stepping
69893cff 576
b570d64b 577=item C<$onetimeDump> - what is to be displayed after the evaluation
69893cff
RGS
578
579=item C<$onetimeDumpDepth> - how deep C<dumpit()> should go when dumping results
580
581=back
582
583The following variables are altered by C<DB::eval()> during its execution. They
b570d64b 584are "stacked" via C<local()>, enabling recursive calls to C<DB::eval()>.
69893cff
RGS
585
586=over 4
587
588=item C<@res> - used to capture output from actual C<eval>.
589
590=item C<$otrace> - saved value of C<$trace>.
591
b570d64b 592=item C<$osingle> - saved value of C<$single>.
69893cff
RGS
593
594=item C<$od> - saved value of C<$^D>.
595
596=item C<$saved[0]> - saved value of C<$@>.
597
b570d64b 598=item $\ - for output of C<$@> if there is an evaluation error.
69893cff
RGS
599
600=back
601
602=head3 The problem of lexicals
603
604The context of C<DB::eval()> presents us with some problems. Obviously,
605we want to be 'sandboxed' away from the debugger's internals when we do
606the eval, but we need some way to control how punctuation variables and
b570d64b 607debugger globals are used.
69893cff
RGS
608
609We can't use local, because the code inside C<DB::eval> can see localized
610variables; and we can't use C<my> either for the same reason. The code
611in this routine compromises and uses C<my>.
612
613After this routine is over, we don't have user code executing in the debugger's
614context, so we can use C<my> freely.
615
616=cut
617
618############################################## Begin lexical danger zone
619
620# 'my' variables used here could leak into (that is, be visible in)
621# the context that the code being evaluated is executing in. This means that
622# the code could modify the debugger's variables.
623#
624# Fiddling with the debugger's context could be Bad. We insulate things as
625# much as we can.
626
6b24a4b7
SF
627use vars qw(
628 @args
629 %break_on_load
630 @cmdfhs
631 $CommandSet
632 $CreateTTY
633 $DBGR
634 @dbline
635 $dbline
636 %dbline
637 $dieLevel
638 $evalarg
639 $filename
640 $frame
641 $hist
642 $histfile
643 $histsize
644 $ImmediateStop
645 $IN
646 $inhibit_exit
647 @ini_INC
648 $ini_warn
649 $line
650 $maxtrace
651 $od
652 $onetimeDump
653 $onetimedumpDepth
654 %option
655 @options
656 $osingle
657 $otrace
658 $OUT
659 $packname
660 $pager
661 $post
662 %postponed
663 $prc
664 $pre
665 $pretype
666 $psh
667 @RememberOnROptions
668 $remoteport
669 @res
670 $rl
671 @saved
672 $signal
673 $signalLevel
674 $single
675 $start
676 $sub
677 %sub
678 $subname
679 $term
680 $trace
681 $usercontext
682 $warnLevel
683 $window
684);
685
686# Used to save @ARGV and extract any debugger-related flags.
687use vars qw(@ARGS);
688
689# Used to prevent multiple entries to diesignal()
690# (if for instance diesignal() itself dies)
691use vars qw($panic);
692
693# Used to prevent the debugger from running nonstop
694# after a restart
695use vars qw($second_time);
696
697sub _calc_usercontext {
698 my ($package) = @_;
699
700 # Cancel strict completely for the evaluated code, so the code
701 # the user evaluates won't be affected by it. (Shlomi Fish)
702 return 'no strict; ($@, $!, $^E, $,, $/, $\, $^W) = @saved;'
703 . "package $package;"; # this won't let them modify, alas
704}
705
c1051fcf 706sub eval {
69893cff 707
c1051fcf 708 # 'my' would make it visible from user code
e22ea7cc 709 # but so does local! --tchrist
69893cff 710 # Remember: this localizes @DB::res, not @main::res.
c1051fcf
IZ
711 local @res;
712 {
e22ea7cc
RF
713
714 # Try to keep the user code from messing with us. Save these so that
715 # even if the eval'ed code changes them, we can put them back again.
716 # Needed because the user could refer directly to the debugger's
69893cff
RGS
717 # package globals (and any 'my' variables in this containing scope)
718 # inside the eval(), and we want to try to stay safe.
e22ea7cc 719 local $otrace = $trace;
69893cff
RGS
720 local $osingle = $single;
721 local $od = $^D;
722
723 # Untaint the incoming eval() argument.
724 { ($evalarg) = $evalarg =~ /(.*)/s; }
725
e22ea7cc 726 # $usercontext built in DB::DB near the comment
69893cff
RGS
727 # "set up the context for DB::eval ..."
728 # Evaluate and save any results.
e22ea7cc 729 @res = eval "$usercontext $evalarg;\n"; # '\n' for nice recursive debug
69893cff
RGS
730
731 # Restore those old values.
732 $trace = $otrace;
733 $single = $osingle;
734 $^D = $od;
c1051fcf 735 }
69893cff
RGS
736
737 # Save the current value of $@, and preserve it in the debugger's copy
738 # of the saved precious globals.
c1051fcf 739 my $at = $@;
69893cff
RGS
740
741 # Since we're only saving $@, we only have to localize the array element
742 # that it will be stored in.
e22ea7cc 743 local $saved[0]; # Preserve the old value of $@
c1051fcf 744 eval { &DB::save };
69893cff
RGS
745
746 # Now see whether we need to report an error back to the user.
c1051fcf 747 if ($at) {
69893cff
RGS
748 local $\ = '';
749 print $OUT $at;
750 }
751
752 # Display as required by the caller. $onetimeDump and $onetimedumpDepth
753 # are package globals.
754 elsif ($onetimeDump) {
e22ea7cc
RF
755 if ( $onetimeDump eq 'dump' ) {
756 local $option{dumpDepth} = $onetimedumpDepth
757 if defined $onetimedumpDepth;
758 dumpit( $OUT, \@res );
759 }
760 elsif ( $onetimeDump eq 'methods' ) {
761 methods( $res[0] );
762 }
69893cff 763 } ## end elsif ($onetimeDump)
c1051fcf 764 @res;
69893cff
RGS
765} ## end sub eval
766
767############################################## End lexical danger zone
c1051fcf 768
e22ea7cc
RF
769# After this point it is safe to introduce lexicals.
770# The code being debugged will be executing in its own context, and
69893cff 771# can't see the inside of the debugger.
d338d6fe 772#
e22ea7cc 773# However, one should not overdo it: leave as much control from outside as
69893cff
RGS
774# possible. If you make something a lexical, it's not going to be addressable
775# from outside the debugger even if you know its name.
776
d338d6fe
PP
777# This file is automatically included if you do perl -d.
778# It's probably not useful to include this yourself.
779#
e22ea7cc 780# Before venturing further into these twisty passages, it is
2f7e9187
MS
781# wise to read the perldebguts man page or risk the ire of dragons.
782#
69893cff
RGS
783# (It should be noted that perldebguts will tell you a lot about
784# the underlying mechanics of how the debugger interfaces into the
785# Perl interpreter, but not a lot about the debugger itself. The new
786# comments in this code try to address this problem.)
787
d338d6fe 788# Note that no subroutine call is possible until &DB::sub is defined
36477c24 789# (for subroutines defined outside of the package DB). In fact the same is
d338d6fe 790# true if $deep is not defined.
055fd3a9
GS
791
792# Enhanced by ilya@math.ohio-state.edu (Ilya Zakharevich)
055fd3a9
GS
793
794# modified Perl debugger, to be run from Emacs in perldb-mode
795# Ray Lischner (uunet!mntgfx!lisch) as of 5 Nov 1990
796# Johan Vromans -- upgrade to 4.0 pl 10
797# Ilya Zakharevich -- patches after 5.001 (and some before ;-)
6fae1ad7 798########################################################################
d338d6fe 799
69893cff
RGS
800=head1 DEBUGGER INITIALIZATION
801
802The debugger starts up in phases.
803
804=head2 BASIC SETUP
805
806First, it initializes the environment it wants to run in: turning off
807warnings during its own compilation, defining variables which it will need
808to avoid warnings later, setting itself up to not exit when the program
809terminates, and defaulting to printing return values for the C<r> command.
810
811=cut
812
eda6e075 813# Needed for the statement after exec():
69893cff
RGS
814#
815# This BEGIN block is simply used to switch off warnings during debugger
98dc9551 816# compilation. Probably it would be better practice to fix the warnings,
69893cff 817# but this is how it's done at the moment.
eda6e075 818
e22ea7cc
RF
819BEGIN {
820 $ini_warn = $^W;
821 $^W = 0;
822} # Switch compilation warnings off until another BEGIN.
d12a4851 823
69893cff
RGS
824local ($^W) = 0; # Switch run-time warnings off during init.
825
2cbb2ee1
RGS
826=head2 THREADS SUPPORT
827
828If we are running under a threaded Perl, we require threads and threads::shared
829if the environment variable C<PERL5DB_THREADED> is set, to enable proper
830threaded debugger control. C<-dt> can also be used to set this.
831
832Each new thread will be announced and the debugger prompt will always inform
833you of each new thread created. It will also indicate the thread id in which
834we are currently running within the prompt like this:
835
836 [tid] DB<$i>
837
838Where C<[tid]> is an integer thread id and C<$i> is the familiar debugger
839command prompt. The prompt will show: C<[0]> when running under threads, but
840not actually in a thread. C<[tid]> is consistent with C<gdb> usage.
841
842While running under threads, when you set or delete a breakpoint (etc.), this
b570d64b 843will apply to all threads, not just the currently running one. When you are
2cbb2ee1
RGS
844in a currently executing thread, you will stay there until it completes. With
845the current implementation it is not currently possible to hop from one thread
846to another.
847
848The C<e> and C<E> commands are currently fairly minimal - see C<h e> and C<h E>.
849
850Note that threading support was built into the debugger as of Perl version
851C<5.8.6> and debugger version C<1.2.8>.
852
853=cut
854
855BEGIN {
856 # ensure we can share our non-threaded variables or no-op
857 if ($ENV{PERL5DB_THREADED}) {
858 require threads;
859 require threads::shared;
860 import threads::shared qw(share);
861 $DBGR;
862 share(\$DBGR);
863 lock($DBGR);
864 print "Threads support enabled\n";
865 } else {
866 *lock = sub(*) {};
867 *share = sub(*) {};
868 }
869}
870
2218c045
SF
871# These variables control the execution of 'dumpvar.pl'.
872{
873 package dumpvar;
874 use vars qw(
875 $hashDepth
876 $arrayDepth
877 $dumpDBFiles
878 $dumpPackages
879 $quoteHighBit
880 $printUndef
881 $globPrint
882 $usageOnly
883 );
884}
69893cff 885
2218c045
SF
886# used to control die() reporting in diesignal()
887{
888 package Carp;
889 use vars qw($CarpLevel);
890}
d338d6fe 891
422c59bf 892# without threads, $filename is not defined until DB::DB is called
2cbb2ee1 893foreach my $k (keys (%INC)) {
fb4d8a6c 894 share(\$main::{'_<'.$filename}) if defined $filename;
2cbb2ee1
RGS
895};
896
54d04a52 897# Command-line + PERLLIB:
69893cff 898# Save the contents of @INC before they are modified elsewhere.
54d04a52
IZ
899@ini_INC = @INC;
900
69893cff
RGS
901# This was an attempt to clear out the previous values of various
902# trapped errors. Apparently it didn't help. XXX More info needed!
d338d6fe
PP
903# $prevwarn = $prevdie = $prevbus = $prevsegv = ''; # Does not help?!
904
69893cff
RGS
905# We set these variables to safe values. We don't want to blindly turn
906# off warnings, because other packages may still want them.
e22ea7cc
RF
907$trace = $signal = $single = 0; # Uninitialized warning suppression
908 # (local $^W cannot help - other packages!).
69893cff
RGS
909
910# Default to not exiting when program finishes; print the return
911# value when the 'r' command is used to return from a subroutine.
55497cff 912$inhibit_exit = $option{PrintRet} = 1;
d338d6fe 913
6b24a4b7
SF
914use vars qw($trace_to_depth);
915
5e2b42dd
SF
916# Default to 1E9 so it won't be limited to a certain recursion depth.
917$trace_to_depth = 1E9;
bdba49ad 918
69893cff
RGS
919=head1 OPTION PROCESSING
920
b570d64b
SF
921The debugger's options are actually spread out over the debugger itself and
922C<dumpvar.pl>; some of these are variables to be set, while others are
69893cff
RGS
923subs to be called with a value. To try to make this a little easier to
924manage, the debugger uses a few data structures to define what options
925are legal and how they are to be processed.
926
927First, the C<@options> array defines the I<names> of all the options that
928are to be accepted.
929
930=cut
931
932@options = qw(
5561b870 933 CommandSet HistFile HistSize
e22ea7cc
RF
934 hashDepth arrayDepth dumpDepth
935 DumpDBFiles DumpPackages DumpReused
936 compactDump veryCompact quote
937 HighBit undefPrint globPrint
938 PrintRet UsageOnly frame
939 AutoTrace TTY noTTY
940 ReadLine NonStop LineInfo
941 maxTraceLen recallCommand ShellBang
942 pager tkRunning ornaments
943 signalLevel warnLevel dieLevel
944 inhibit_exit ImmediateStop bareStringify
945 CreateTTY RemotePort windowSize
584420f0 946 DollarCaretP
e22ea7cc 947);
d12a4851 948
584420f0 949@RememberOnROptions = qw(DollarCaretP);
d12a4851 950
69893cff
RGS
951=pod
952
953Second, C<optionVars> lists the variables that each option uses to save its
954state.
955
956=cut
957
6b24a4b7
SF
958use vars qw(%optionVars);
959
69893cff 960%optionVars = (
e22ea7cc
RF
961 hashDepth => \$dumpvar::hashDepth,
962 arrayDepth => \$dumpvar::arrayDepth,
963 CommandSet => \$CommandSet,
964 DumpDBFiles => \$dumpvar::dumpDBFiles,
965 DumpPackages => \$dumpvar::dumpPackages,
966 DumpReused => \$dumpvar::dumpReused,
967 HighBit => \$dumpvar::quoteHighBit,
968 undefPrint => \$dumpvar::printUndef,
969 globPrint => \$dumpvar::globPrint,
970 UsageOnly => \$dumpvar::usageOnly,
971 CreateTTY => \$CreateTTY,
972 bareStringify => \$dumpvar::bareStringify,
973 frame => \$frame,
974 AutoTrace => \$trace,
975 inhibit_exit => \$inhibit_exit,
976 maxTraceLen => \$maxtrace,
977 ImmediateStop => \$ImmediateStop,
978 RemotePort => \$remoteport,
979 windowSize => \$window,
5561b870
AK
980 HistFile => \$histfile,
981 HistSize => \$histsize,
69893cff
RGS
982);
983
984=pod
985
986Third, C<%optionAction> defines the subroutine to be called to process each
987option.
988
b570d64b 989=cut
69893cff 990
6b24a4b7
SF
991use vars qw(%optionAction);
992
69893cff
RGS
993%optionAction = (
994 compactDump => \&dumpvar::compactDump,
995 veryCompact => \&dumpvar::veryCompact,
996 quote => \&dumpvar::quote,
997 TTY => \&TTY,
998 noTTY => \&noTTY,
999 ReadLine => \&ReadLine,
1000 NonStop => \&NonStop,
1001 LineInfo => \&LineInfo,
1002 recallCommand => \&recallCommand,
1003 ShellBang => \&shellBang,
1004 pager => \&pager,
1005 signalLevel => \&signalLevel,
1006 warnLevel => \&warnLevel,
1007 dieLevel => \&dieLevel,
1008 tkRunning => \&tkRunning,
1009 ornaments => \&ornaments,
1010 RemotePort => \&RemotePort,
1011 DollarCaretP => \&DollarCaretP,
d12a4851
JH
1012);
1013
69893cff
RGS
1014=pod
1015
1016Last, the C<%optionRequire> notes modules that must be C<require>d if an
1017option is used.
1018
1019=cut
d338d6fe 1020
69893cff
RGS
1021# Note that this list is not complete: several options not listed here
1022# actually require that dumpvar.pl be loaded for them to work, but are
1023# not in the table. A subsequent patch will correct this problem; for
1024# the moment, we're just recommenting, and we are NOT going to change
1025# function.
6b24a4b7
SF
1026use vars qw(%optionRequire);
1027
eda6e075 1028%optionRequire = (
69893cff
RGS
1029 compactDump => 'dumpvar.pl',
1030 veryCompact => 'dumpvar.pl',
1031 quote => 'dumpvar.pl',
e22ea7cc 1032);
69893cff
RGS
1033
1034=pod
1035
1036There are a number of initialization-related variables which can be set
1037by putting code to set them in a BEGIN block in the C<PERL5DB> environment
1038variable. These are:
1039
1040=over 4
1041
1042=item C<$rl> - readline control XXX needs more explanation
1043
1044=item C<$warnLevel> - whether or not debugger takes over warning handling
1045
1046=item C<$dieLevel> - whether or not debugger takes over die handling
1047
1048=item C<$signalLevel> - whether or not debugger takes over signal handling
1049
1050=item C<$pre> - preprompt actions (array reference)
1051
1052=item C<$post> - postprompt actions (array reference)
1053
1054=item C<$pretype>
1055
1056=item C<$CreateTTY> - whether or not to create a new TTY for this debugger
1057
1058=item C<$CommandSet> - which command set to use (defaults to new, documented set)
1059
1060=back
1061
1062=cut
d338d6fe
PP
1063
1064# These guys may be defined in $ENV{PERL5DB} :
69893cff
RGS
1065$rl = 1 unless defined $rl;
1066$warnLevel = 1 unless defined $warnLevel;
1067$dieLevel = 1 unless defined $dieLevel;
1068$signalLevel = 1 unless defined $signalLevel;
1069$pre = [] unless defined $pre;
1070$post = [] unless defined $post;
1071$pretype = [] unless defined $pretype;
1072$CreateTTY = 3 unless defined $CreateTTY;
1073$CommandSet = '580' unless defined $CommandSet;
1074
2cbb2ee1
RGS
1075share($rl);
1076share($warnLevel);
1077share($dieLevel);
1078share($signalLevel);
1079share($pre);
1080share($post);
1081share($pretype);
1082share($rl);
1083share($CreateTTY);
1084share($CommandSet);
1085
69893cff
RGS
1086=pod
1087
1088The default C<die>, C<warn>, and C<signal> handlers are set up.
1089
1090=cut
055fd3a9 1091
d338d6fe
PP
1092warnLevel($warnLevel);
1093dieLevel($dieLevel);
1094signalLevel($signalLevel);
055fd3a9 1095
69893cff
RGS
1096=pod
1097
1098The pager to be used is needed next. We try to get it from the
5561b870 1099environment first. If it's not defined there, we try to find it in
69893cff
RGS
1100the Perl C<Config.pm>. If it's not there, we default to C<more>. We
1101then call the C<pager()> function to save the pager name.
1102
1103=cut
1104
1105# This routine makes sure $pager is set up so that '|' can use it.
4865a36d 1106pager(
e22ea7cc 1107
69893cff 1108 # If PAGER is defined in the environment, use it.
e22ea7cc
RF
1109 defined $ENV{PAGER}
1110 ? $ENV{PAGER}
69893cff
RGS
1111
1112 # If not, see if Config.pm defines it.
e22ea7cc
RF
1113 : eval { require Config }
1114 && defined $Config::Config{pager}
1115 ? $Config::Config{pager}
69893cff
RGS
1116
1117 # If not, fall back to 'more'.
e22ea7cc
RF
1118 : 'more'
1119 )
1120 unless defined $pager;
69893cff
RGS
1121
1122=pod
1123
1124We set up the command to be used to access the man pages, the command
be9a9b1d
AT
1125recall character (C<!> unless otherwise defined) and the shell escape
1126character (C<!> unless otherwise defined). Yes, these do conflict, and
69893cff
RGS
1127neither works in the debugger at the moment.
1128
1129=cut
1130
055fd3a9 1131setman();
69893cff
RGS
1132
1133# Set up defaults for command recall and shell escape (note:
1134# these currently don't work in linemode debugging).
2218c045
SF
1135recallCommand("!") unless defined $prc;
1136shellBang("!") unless defined $psh;
69893cff
RGS
1137
1138=pod
1139
1140We then set up the gigantic string containing the debugger help.
1141We also set the limit on the number of arguments we'll display during a
1142trace.
1143
1144=cut
1145
04e43a21 1146sethelp();
69893cff
RGS
1147
1148# If we didn't get a default for the length of eval/stack trace args,
1149# set it here.
1d06cb2d 1150$maxtrace = 400 unless defined $maxtrace;
69893cff
RGS
1151
1152=head2 SETTING UP THE DEBUGGER GREETING
1153
be9a9b1d 1154The debugger I<greeting> helps to inform the user how many debuggers are
69893cff
RGS
1155running, and whether the current debugger is the primary or a child.
1156
1157If we are the primary, we just hang onto our pid so we'll have it when
1158or if we start a child debugger. If we are a child, we'll set things up
1159so we'll have a unique greeting and so the parent will give us our own
1160TTY later.
1161
1162We save the current contents of the C<PERLDB_PIDS> environment variable
1163because we mess around with it. We'll also need to hang onto it because
1164we'll need it if we restart.
1165
1166Child debuggers make a label out of the current PID structure recorded in
1167PERLDB_PIDS plus the new PID. They also mark themselves as not having a TTY
1168yet so the parent will give them one later via C<resetterm()>.
1169
1170=cut
1171
e22ea7cc 1172# Save the current contents of the environment; we're about to
69893cff 1173# much with it. We'll need this if we have to restart.
6b24a4b7 1174use vars qw($ini_pids);
f1583d8f 1175$ini_pids = $ENV{PERLDB_PIDS};
69893cff 1176
6b24a4b7
SF
1177use vars qw ($pids $term_pid);
1178
e22ea7cc
RF
1179if ( defined $ENV{PERLDB_PIDS} ) {
1180
69893cff 1181 # We're a child. Make us a label out of the current PID structure
e22ea7cc 1182 # recorded in PERLDB_PIDS plus our (new) PID. Mark us as not having
69893cff 1183 # a term yet so the parent will give us one later via resetterm().
55f4245e
JM
1184
1185 my $env_pids = $ENV{PERLDB_PIDS};
1186 $pids = "[$env_pids]";
1187
1188 # Unless we are on OpenVMS, all programs under the DCL shell run under
1189 # the same PID.
1190
1191 if (($^O eq 'VMS') && ($env_pids =~ /\b$$\b/)) {
1192 $term_pid = $$;
1193 }
1194 else {
1195 $ENV{PERLDB_PIDS} .= "->$$";
1196 $term_pid = -1;
1197 }
1198
69893cff
RGS
1199} ## end if (defined $ENV{PERLDB_PIDS...
1200else {
e22ea7cc
RF
1201
1202 # We're the parent PID. Initialize PERLDB_PID in case we end up with a
69893cff
RGS
1203 # child debugger, and mark us as the parent, so we'll know to set up
1204 # more TTY's is we have to.
1205 $ENV{PERLDB_PIDS} = "$$";
619a0444 1206 $pids = "[pid=$$]";
e22ea7cc 1207 $term_pid = $$;
f1583d8f 1208}
69893cff 1209
6b24a4b7 1210use vars qw($pidprompt);
f1583d8f 1211$pidprompt = '';
69893cff
RGS
1212
1213# Sets up $emacs as a synonym for $slave_editor.
6b24a4b7 1214use vars qw($slave_editor);
69893cff
RGS
1215*emacs = $slave_editor if $slave_editor; # May be used in afterinit()...
1216
1217=head2 READING THE RC FILE
1218
b570d64b 1219The debugger will read a file of initialization options if supplied. If
69893cff
RGS
1220running interactively, this is C<.perldb>; if not, it's C<perldb.ini>.
1221
b570d64b 1222=cut
69893cff
RGS
1223
1224# As noted, this test really doesn't check accurately that the debugger
1225# is running at a terminal or not.
d338d6fe 1226
6b24a4b7 1227use vars qw($rcfile);
fb4d8a6c
SF
1228{
1229 my $dev_tty = (($^O eq 'VMS') ? 'TT:' : '/dev/tty');
1230 # this is the wrong metric!
1231 $rcfile = ((-e $dev_tty) ? ".perldb" : "perldb.ini");
d338d6fe
PP
1232}
1233
69893cff
RGS
1234=pod
1235
1236The debugger does a safety test of the file to be read. It must be owned
1237either by the current user or root, and must only be writable by the owner.
1238
1239=cut
1240
1241# This wraps a safety test around "do" to read and evaluate the init file.
1242#
055fd3a9
GS
1243# This isn't really safe, because there's a race
1244# between checking and opening. The solution is to
1245# open and fstat the handle, but then you have to read and
1246# eval the contents. But then the silly thing gets
69893cff
RGS
1247# your lexical scope, which is unfortunate at best.
1248sub safe_do {
055fd3a9
GS
1249 my $file = shift;
1250
1251 # Just exactly what part of the word "CORE::" don't you understand?
69893cff
RGS
1252 local $SIG{__WARN__};
1253 local $SIG{__DIE__};
055fd3a9 1254
e22ea7cc 1255 unless ( is_safe_file($file) ) {
69893cff 1256 CORE::warn <<EO_GRIPE;
055fd3a9 1257perldb: Must not source insecure rcfile $file.
b570d64b 1258 You or the superuser must be the owner, and it must not
69893cff 1259 be writable by anyone but its owner.
055fd3a9 1260EO_GRIPE
69893cff
RGS
1261 return;
1262 } ## end unless (is_safe_file($file...
055fd3a9
GS
1263
1264 do $file;
1265 CORE::warn("perldb: couldn't parse $file: $@") if $@;
69893cff 1266} ## end sub safe_do
055fd3a9 1267
69893cff
RGS
1268# This is the safety test itself.
1269#
055fd3a9
GS
1270# Verifies that owner is either real user or superuser and that no
1271# one but owner may write to it. This function is of limited use
1272# when called on a path instead of upon a handle, because there are
1273# no guarantees that filename (by dirent) whose file (by ino) is
e22ea7cc 1274# eventually accessed is the same as the one tested.
055fd3a9
GS
1275# Assumes that the file's existence is not in doubt.
1276sub is_safe_file {
1277 my $path = shift;
69893cff 1278 stat($path) || return; # mysteriously vaporized
e22ea7cc 1279 my ( $dev, $ino, $mode, $nlink, $uid, $gid ) = stat(_);
055fd3a9
GS
1280
1281 return 0 if $uid != 0 && $uid != $<;
1282 return 0 if $mode & 022;
1283 return 1;
69893cff 1284} ## end sub is_safe_file
055fd3a9 1285
69893cff 1286# If the rcfile (whichever one we decided was the right one to read)
e22ea7cc
RF
1287# exists, we safely do it.
1288if ( -f $rcfile ) {
055fd3a9 1289 safe_do("./$rcfile");
69893cff 1290}
e22ea7cc 1291
69893cff 1292# If there isn't one here, try the user's home directory.
e22ea7cc 1293elsif ( defined $ENV{HOME} && -f "$ENV{HOME}/$rcfile" ) {
055fd3a9
GS
1294 safe_do("$ENV{HOME}/$rcfile");
1295}
e22ea7cc 1296
69893cff 1297# Else try the login directory.
e22ea7cc 1298elsif ( defined $ENV{LOGDIR} && -f "$ENV{LOGDIR}/$rcfile" ) {
055fd3a9 1299 safe_do("$ENV{LOGDIR}/$rcfile");
d338d6fe
PP
1300}
1301
69893cff 1302# If the PERLDB_OPTS variable has options in it, parse those out next.
e22ea7cc
RF
1303if ( defined $ENV{PERLDB_OPTS} ) {
1304 parse_options( $ENV{PERLDB_OPTS} );
d338d6fe
PP
1305}
1306
69893cff
RGS
1307=pod
1308
1309The last thing we do during initialization is determine which subroutine is
1310to be used to obtain a new terminal when a new debugger is started. Right now,
b0b54b5e 1311the debugger only handles TCP sockets, X11, OS/2, amd Mac OS X
11653f7f 1312(darwin).
69893cff
RGS
1313
1314=cut
1315
1316# Set up the get_fork_TTY subroutine to be aliased to the proper routine.
1317# Works if you're running an xterm or xterm-like window, or you're on
6fae1ad7
RF
1318# OS/2, or on Mac OS X. This may need some expansion.
1319
1320if (not defined &get_fork_TTY) # only if no routine exists
69893cff 1321{
b570d64b 1322 if ( defined $remoteport ) {
11653f7f
JJ
1323 # Expect an inetd-like server
1324 *get_fork_TTY = \&socket_get_fork_TTY; # to listen to us
1325 }
1326 elsif (defined $ENV{TERM} # If we know what kind
6fae1ad7
RF
1327 # of terminal this is,
1328 and $ENV{TERM} eq 'xterm' # and it's an xterm,
1329 and defined $ENV{DISPLAY} # and what display it's on,
1330 )
1331 {
1332 *get_fork_TTY = \&xterm_get_fork_TTY; # use the xterm version
1333 }
1334 elsif ( $^O eq 'os2' ) { # If this is OS/2,
1335 *get_fork_TTY = \&os2_get_fork_TTY; # use the OS/2 version
1336 }
1337 elsif ( $^O eq 'darwin' # If this is Mac OS X
1338 and defined $ENV{TERM_PROGRAM} # and we're running inside
1339 and $ENV{TERM_PROGRAM}
1340 eq 'Apple_Terminal' # Terminal.app
1341 )
1342 {
1343 *get_fork_TTY = \&macosx_get_fork_TTY; # use the Mac OS X version
1344 }
69893cff 1345} ## end if (not defined &get_fork_TTY...
e22ea7cc 1346
dbb46cec
DQ
1347# untaint $^O, which may have been tainted by the last statement.
1348# see bug [perl #24674]
e22ea7cc
RF
1349$^O =~ m/^(.*)\z/;
1350$^O = $1;
f1583d8f 1351
d12a4851 1352# Here begin the unreadable code. It needs fixing.
055fd3a9 1353
69893cff
RGS
1354=head2 RESTART PROCESSING
1355
1356This section handles the restart command. When the C<R> command is invoked, it
1357tries to capture all of the state it can into environment variables, and
1358then sets C<PERLDB_RESTART>. When we start executing again, we check to see
1359if C<PERLDB_RESTART> is there; if so, we reload all the information that
1360the R command stuffed into the environment variables.
1361
b570d64b 1362 PERLDB_RESTART - flag only, contains no restart data itself.
69893cff
RGS
1363 PERLDB_HIST - command history, if it's available
1364 PERLDB_ON_LOAD - breakpoints set by the rc file
1365 PERLDB_POSTPONE - subs that have been loaded/not executed, and have actions
1366 PERLDB_VISITED - files that had breakpoints
1367 PERLDB_FILE_... - breakpoints for a file
1368 PERLDB_OPT - active options
1369 PERLDB_INC - the original @INC
1370 PERLDB_PRETYPE - preprompt debugger actions
1371 PERLDB_PRE - preprompt Perl code
1372 PERLDB_POST - post-prompt Perl code
1373 PERLDB_TYPEAHEAD - typeahead captured by readline()
1374
1375We chug through all these variables and plug the values saved in them
1376back into the appropriate spots in the debugger.
1377
1378=cut
1379
6b24a4b7
SF
1380use vars qw(@hist @truehist %postponed_file @typeahead);
1381
fb0fb5f4
SF
1382sub _restore_shared_globals_after_restart
1383{
1384 @hist = get_list('PERLDB_HIST');
1385 %break_on_load = get_list("PERLDB_ON_LOAD");
1386 %postponed = get_list("PERLDB_POSTPONE");
1387
1388 share(@hist);
1389 share(@truehist);
1390 share(%break_on_load);
1391 share(%postponed);
1392}
1393
e18a02a6 1394sub _restore_breakpoints_and_actions {
e22ea7cc 1395
e22ea7cc 1396 my @had_breakpoints = get_list("PERLDB_VISITED");
e18a02a6 1397
bdba49ad
SF
1398 for my $file_idx ( 0 .. $#had_breakpoints ) {
1399 my $filename = $had_breakpoints[$file_idx];
1400 my %pf = get_list("PERLDB_FILE_$file_idx");
1401 $postponed_file{ $filename } = \%pf if %pf;
1402 my @lines = sort {$a <=> $b} keys(%pf);
1403 my @enabled_statuses = get_list("PERLDB_FILE_ENABLED_$file_idx");
1404 for my $line_idx (0 .. $#lines) {
1405 _set_breakpoint_enabled_status(
1406 $filename,
1407 $lines[$line_idx],
1408 ($enabled_statuses[$line_idx] ? 1 : ''),
1409 );
1410 }
e22ea7cc 1411 }
69893cff 1412
e18a02a6
SF
1413 return;
1414}
1415
ca50076b
SF
1416sub _restore_options_after_restart
1417{
1418 my %options_map = get_list("PERLDB_OPT");
1419
1420 while ( my ( $opt, $val ) = each %options_map ) {
1421 $val =~ s/[\\\']/\\$1/g;
1422 parse_options("$opt'$val'");
1423 }
1424
1425 return;
1426}
1427
18580168
SF
1428sub _restore_globals_after_restart
1429{
1430 # restore original @INC
1431 @INC = get_list("PERLDB_INC");
1432 @ini_INC = @INC;
1433
1434 # return pre/postprompt actions and typeahead buffer
1435 $pretype = [ get_list("PERLDB_PRETYPE") ];
1436 $pre = [ get_list("PERLDB_PRE") ];
1437 $post = [ get_list("PERLDB_POST") ];
1438 @typeahead = get_list( "PERLDB_TYPEAHEAD", @typeahead );
1439
1440 return;
1441}
1442
fb0fb5f4 1443
e18a02a6
SF
1444if ( exists $ENV{PERLDB_RESTART} ) {
1445
1446 # We're restarting, so we don't need the flag that says to restart anymore.
1447 delete $ENV{PERLDB_RESTART};
1448
1449 # $restart = 1;
fb0fb5f4 1450 _restore_shared_globals_after_restart();
e18a02a6
SF
1451
1452 _restore_breakpoints_and_actions();
1453
69893cff 1454 # restore options
ca50076b 1455 _restore_options_after_restart();
69893cff 1456
18580168 1457 _restore_globals_after_restart();
69893cff
RGS
1458} ## end if (exists $ENV{PERLDB_RESTART...
1459
1460=head2 SETTING UP THE TERMINAL
1461
1462Now, we'll decide how the debugger is going to interact with the user.
1463If there's no TTY, we set the debugger to run non-stop; there's not going
1464to be anyone there to enter commands.
1465
1466=cut
54d04a52 1467
6b24a4b7
SF
1468use vars qw($notty $runnonstop $console $tty $LINEINFO);
1469use vars qw($lineinfo $doccmd);
1470
d338d6fe 1471if ($notty) {
69893cff 1472 $runnonstop = 1;
2cbb2ee1 1473 share($runnonstop);
69893cff 1474}
d12a4851 1475
69893cff
RGS
1476=pod
1477
1478If there is a TTY, we have to determine who it belongs to before we can
1479proceed. If this is a slave editor or graphical debugger (denoted by
1480the first command-line switch being '-emacs'), we shift this off and
1481set C<$rl> to 0 (XXX ostensibly to do straight reads).
1482
1483=cut
1484
1485else {
e22ea7cc 1486
69893cff
RGS
1487 # Is Perl being run from a slave editor or graphical debugger?
1488 # If so, don't use readline, and set $slave_editor = 1.
e22ea7cc
RF
1489 $slave_editor =
1490 ( ( defined $main::ARGV[0] ) and ( $main::ARGV[0] eq '-emacs' ) );
1491 $rl = 0, shift(@main::ARGV) if $slave_editor;
1492
1493 #require Term::ReadLine;
d12a4851 1494
69893cff
RGS
1495=pod
1496
1497We then determine what the console should be on various systems:
1498
1499=over 4
1500
1501=item * Cygwin - We use C<stdin> instead of a separate device.
1502
1503=cut
1504
e22ea7cc
RF
1505 if ( $^O eq 'cygwin' ) {
1506
69893cff
RGS
1507 # /dev/tty is binary. use stdin for textmode
1508 undef $console;
1509 }
1510
1511=item * Unix - use C</dev/tty>.
1512
1513=cut
1514
e22ea7cc 1515 elsif ( -e "/dev/tty" ) {
69893cff
RGS
1516 $console = "/dev/tty";
1517 }
1518
1519=item * Windows or MSDOS - use C<con>.
1520
1521=cut
1522
e22ea7cc 1523 elsif ( $^O eq 'dos' or -e "con" or $^O eq 'MSWin32' ) {
69893cff
RGS
1524 $console = "con";
1525 }
1526
69893cff
RGS
1527=item * VMS - use C<sys$command>.
1528
1529=cut
1530
1531 else {
e22ea7cc 1532
69893cff
RGS
1533 # everything else is ...
1534 $console = "sys\$command";
d12a4851 1535 }
69893cff
RGS
1536
1537=pod
1538
1539=back
1540
1541Several other systems don't use a specific console. We C<undef $console>
1542for those (Windows using a slave editor/graphical debugger, NetWare, OS/2
1543with a slave editor, Epoc).
1544
1545=cut
d12a4851 1546
e22ea7cc
RF
1547 if ( ( $^O eq 'MSWin32' ) and ( $slave_editor or defined $ENV{EMACS} ) ) {
1548
69893cff 1549 # /dev/tty is binary. use stdin for textmode
e22ea7cc
RF
1550 $console = undef;
1551 }
1552
1553 if ( $^O eq 'NetWare' ) {
d12a4851 1554
69893cff
RGS
1555 # /dev/tty is binary. use stdin for textmode
1556 $console = undef;
1557 }
d12a4851 1558
69893cff
RGS
1559 # In OS/2, we need to use STDIN to get textmode too, even though
1560 # it pretty much looks like Unix otherwise.
e22ea7cc
RF
1561 if ( defined $ENV{OS2_SHELL} and ( $slave_editor or $ENV{WINDOWID} ) )
1562 { # In OS/2
1563 $console = undef;
1564 }
1565
1566 # EPOC also falls into the 'got to use STDIN' camp.
1567 if ( $^O eq 'epoc' ) {
1568 $console = undef;
1569 }
d12a4851 1570
69893cff
RGS
1571=pod
1572
1573If there is a TTY hanging around from a parent, we use that as the console.
1574
1575=cut
1576
e22ea7cc 1577 $console = $tty if defined $tty;
d12a4851 1578
b570d64b 1579=head2 SOCKET HANDLING
69893cff
RGS
1580
1581The debugger is capable of opening a socket and carrying out a debugging
1582session over the socket.
1583
1584If C<RemotePort> was defined in the options, the debugger assumes that it
1585should try to start a debugging session on that port. It builds the socket
1586and then tries to connect the input and output filehandles to it.
1587
1588=cut
1589
1590 # Handle socket stuff.
e22ea7cc
RF
1591
1592 if ( defined $remoteport ) {
1593
69893cff
RGS
1594 # If RemotePort was defined in the options, connect input and output
1595 # to the socket.
11653f7f 1596 $IN = $OUT = connect_remoteport();
69893cff
RGS
1597 } ## end if (defined $remoteport)
1598
1599=pod
1600
1601If no C<RemotePort> was defined, and we want to create a TTY on startup,
1602this is probably a situation where multiple debuggers are running (for example,
1603a backticked command that starts up another debugger). We create a new IN and
1604OUT filehandle, and do the necessary mojo to create a new TTY if we know how
1605and if we can.
1606
1607=cut
1608
1609 # Non-socket.
1610 else {
e22ea7cc 1611
69893cff
RGS
1612 # Two debuggers running (probably a system or a backtick that invokes
1613 # the debugger itself under the running one). create a new IN and OUT
e22ea7cc 1614 # filehandle, and do the necessary mojo to create a new tty if we
69893cff 1615 # know how, and we can.
e22ea7cc
RF
1616 create_IN_OUT(4) if $CreateTTY & 4;
1617 if ($console) {
1618
69893cff 1619 # If we have a console, check to see if there are separate ins and
cd1191f1 1620 # outs to open. (They are assumed identical if not.)
69893cff 1621
e22ea7cc
RF
1622 my ( $i, $o ) = split /,/, $console;
1623 $o = $i unless defined $o;
69893cff 1624
69893cff 1625 # read/write on in, or just read, or read on STDIN.
e22ea7cc
RF
1626 open( IN, "+<$i" )
1627 || open( IN, "<$i" )
1628 || open( IN, "<&STDIN" );
1629
69893cff
RGS
1630 # read/write/create/clobber out, or write/create/clobber out,
1631 # or merge with STDERR, or merge with STDOUT.
e22ea7cc
RF
1632 open( OUT, "+>$o" )
1633 || open( OUT, ">$o" )
1634 || open( OUT, ">&STDERR" )
1635 || open( OUT, ">&STDOUT" ); # so we don't dongle stdout
1636
1637 } ## end if ($console)
1638 elsif ( not defined $console ) {
1639
1640 # No console. Open STDIN.
1641 open( IN, "<&STDIN" );
1642
1643 # merge with STDERR, or with STDOUT.
1644 open( OUT, ">&STDERR" )
1645 || open( OUT, ">&STDOUT" ); # so we don't dongle stdout
1646 $console = 'STDIN/OUT';
69893cff
RGS
1647 } ## end elsif (not defined $console)
1648
1649 # Keep copies of the filehandles so that when the pager runs, it
1650 # can close standard input without clobbering ours.
e22ea7cc
RF
1651 $IN = \*IN, $OUT = \*OUT if $console or not defined $console;
1652 } ## end elsif (from if(defined $remoteport))
1653
1654 # Unbuffer DB::OUT. We need to see responses right away.
70c9432b 1655 $OUT->autoflush(1);
e22ea7cc
RF
1656
1657 # Line info goes to debugger output unless pointed elsewhere.
1658 # Pointing elsewhere makes it possible for slave editors to
1659 # keep track of file and position. We have both a filehandle
1660 # and a I/O description to keep track of.
1661 $LINEINFO = $OUT unless defined $LINEINFO;
1662 $lineinfo = $console unless defined $lineinfo;
2cbb2ee1 1663 # share($LINEINFO); # <- unable to share globs
b570d64b 1664 share($lineinfo); #
e22ea7cc 1665
69893cff
RGS
1666=pod
1667
1668To finish initialization, we show the debugger greeting,
1669and then call the C<afterinit()> subroutine if there is one.
1670
1671=cut
d12a4851 1672
e22ea7cc
RF
1673 # Show the debugger greeting.
1674 $header =~ s/.Header: ([^,]+),v(\s+\S+\s+\S+).*$/$1$2/;
1675 unless ($runnonstop) {
1676 local $\ = '';
1677 local $, = '';
1678 if ( $term_pid eq '-1' ) {
1679 print $OUT "\nDaughter DB session started...\n";
1680 }
1681 else {
1682 print $OUT "\nLoading DB routines from $header\n";
1683 print $OUT (
1684 "Editor support ",
1685 $slave_editor ? "enabled" : "available", ".\n"
1686 );
1687 print $OUT
1f874cb6 1688"\nEnter h or 'h h' for help, or '$doccmd perldebug' for more help.\n\n";
69893cff
RGS
1689 } ## end else [ if ($term_pid eq '-1')
1690 } ## end unless ($runnonstop)
1691} ## end else [ if ($notty)
1692
1693# XXX This looks like a bug to me.
1694# Why copy to @ARGS and then futz with @args?
d338d6fe 1695@ARGS = @ARGV;
6b24a4b7 1696# for (@args) {
69893cff
RGS
1697 # Make sure backslashes before single quotes are stripped out, and
1698 # keep args unless they are numeric (XXX why?)
e22ea7cc
RF
1699 # s/\'/\\\'/g; # removed while not justified understandably
1700 # s/(.*)/'$1'/ unless /^-?[\d.]+$/; # ditto
6b24a4b7 1701# }
d338d6fe 1702
e22ea7cc 1703# If there was an afterinit() sub defined, call it. It will get
69893cff 1704# executed in our scope, so it can fiddle with debugger globals.
e22ea7cc 1705if ( defined &afterinit ) { # May be defined in $rcfile
69893cff 1706 &afterinit();
d338d6fe 1707}
e22ea7cc 1708
69893cff 1709# Inform us about "Stack dump during die enabled ..." in dieLevel().
6b24a4b7
SF
1710use vars qw($I_m_init);
1711
43aed9ee
IZ
1712$I_m_init = 1;
1713
d338d6fe
PP
1714############################################################ Subroutines
1715
69893cff
RGS
1716=head1 SUBROUTINES
1717
1718=head2 DB
1719
1720This gigantic subroutine is the heart of the debugger. Called before every
1721statement, its job is to determine if a breakpoint has been reached, and
1722stop if so; read commands from the user, parse them, and execute
b468dcb6 1723them, and then send execution off to the next statement.
69893cff
RGS
1724
1725Note that the order in which the commands are processed is very important;
1726some commands earlier in the loop will actually alter the C<$cmd> variable
be9a9b1d 1727to create other commands to be executed later. This is all highly I<optimized>
69893cff
RGS
1728but can be confusing. Check the comments for each C<$cmd ... && do {}> to
1729see what's happening in any given command.
1730
1731=cut
1732
6b24a4b7
SF
1733use vars qw(
1734 $action
1735 %alias
1736 $cmd
1737 $doret
1738 $fall_off_end
1739 $file
1740 $filename_ini
1741 $finished
1742 %had_breakpoints
1743 $incr
1744 $laststep
1745 $level
1746 $max
1747 @old_watch
1748 $package
1749 $rc
1750 $sh
1751 @stack
1752 $stack_depth
1753 @to_watch
1754 $try
2c247e84 1755 $end
6b24a4b7
SF
1756);
1757
d338d6fe 1758sub DB {
69893cff 1759
2cbb2ee1
RGS
1760 # lock the debugger and get the thread id for the prompt
1761 lock($DBGR);
1762 my $tid;
6b24a4b7
SF
1763 my $position;
1764 my ($prefix, $after, $infix);
1765 my $pat;
6b24a4b7 1766
2cbb2ee1 1767 if ($ENV{PERL5DB_THREADED}) {
878090d5 1768 $tid = eval { "[".threads->tid."]" };
2cbb2ee1
RGS
1769 }
1770
69893cff 1771 # Check for whether we should be running continuously or not.
36477c24 1772 # _After_ the perl program is compiled, $single is set to 1:
e22ea7cc
RF
1773 if ( $single and not $second_time++ ) {
1774
69893cff 1775 # Options say run non-stop. Run until we get an interrupt.
e22ea7cc
RF
1776 if ($runnonstop) { # Disable until signal
1777 # If there's any call stack in place, turn off single
1778 # stepping into subs throughout the stack.
2c247e84 1779 for my $i (0 .. $stack_depth) {
72d7d80d 1780 $stack[ $i ] &= ~1;
e22ea7cc
RF
1781 }
1782
69893cff 1783 # And we are now no longer in single-step mode.
e22ea7cc 1784 $single = 0;
69893cff
RGS
1785
1786 # If we simply returned at this point, we wouldn't get
1787 # the trace info. Fall on through.
e22ea7cc 1788 # return;
69893cff
RGS
1789 } ## end if ($runnonstop)
1790
e22ea7cc
RF
1791 elsif ($ImmediateStop) {
1792
1793 # We are supposed to stop here; XXX probably a break.
1794 $ImmediateStop = 0; # We've processed it; turn it off
1795 $signal = 1; # Simulate an interrupt to force
1796 # us into the command loop
69893cff
RGS
1797 }
1798 } ## end if ($single and not $second_time...
1799
1800 # If we're in single-step mode, or an interrupt (real or fake)
1801 # has occurred, turn off non-stop mode.
1802 $runnonstop = 0 if $single or $signal;
1803
1804 # Preserve current values of $@, $!, $^E, $,, $/, $\, $^W.
1805 # The code being debugged may have altered them.
d338d6fe 1806 &save;
69893cff
RGS
1807
1808 # Since DB::DB gets called after every line, we can use caller() to
1809 # figure out where we last were executing. Sneaky, eh? This works because
e22ea7cc 1810 # caller is returning all the extra information when called from the
69893cff 1811 # debugger.
e22ea7cc 1812 local ( $package, $filename, $line ) = caller;
6b24a4b7 1813 $filename_ini = $filename;
69893cff
RGS
1814
1815 # set up the context for DB::eval, so it can properly execute
1816 # code on behalf of the user. We add the package in so that the
1817 # code is eval'ed in the proper package (not in the debugger!).
6b24a4b7 1818 local $usercontext = _calc_usercontext($package);
69893cff
RGS
1819
1820 # Create an alias to the active file magical array to simplify
1821 # the code here.
e22ea7cc 1822 local (*dbline) = $main::{ '_<' . $filename };
aa057b67 1823
69893cff 1824 # Last line in the program.
55783941 1825 $max = $#dbline;
69893cff
RGS
1826
1827 # if we have something here, see if we should break.
e22ea7cc 1828 {
72d7d80d
SF
1829 # $stop is lexical and local to this block - $action on the other hand
1830 # is global.
1831 my $stop;
e22ea7cc 1832
72d7d80d
SF
1833 if ( $dbline{$line}
1834 && _is_breakpoint_enabled($filename, $line)
1835 && (( $stop, $action ) = split( /\0/, $dbline{$line} ) ) )
1836 {
e22ea7cc 1837
72d7d80d
SF
1838 # Stop if the stop criterion says to just stop.
1839 if ( $stop eq '1' ) {
1840 $signal |= 1;
5d5d9ea3 1841 }
72d7d80d
SF
1842
1843 # It's a conditional stop; eval it in the user's context and
1844 # see if we should stop. If so, remove the one-time sigil.
1845 elsif ($stop) {
1846 $evalarg = "\$DB::signal |= 1 if do {$stop}";
1847 &eval;
1848 # If the breakpoint is temporary, then delete its enabled status.
1849 if ($dbline{$line} =~ s/;9($|\0)/$1/) {
1850 _cancel_breakpoint_temp_enabled_status($filename, $line);
1851 }
1852 }
1853 } ## end if ($dbline{$line} && ...
1854 }
69893cff
RGS
1855
1856 # Preserve the current stop-or-not, and see if any of the W
1857 # (watch expressions) has changed.
36477c24 1858 my $was_signal = $signal;
69893cff
RGS
1859
1860 # If we have any watch expressions ...
e22ea7cc 1861 if ( $trace & 2 ) {
2c247e84 1862 for my $n (0 .. $#to_watch) {
e22ea7cc
RF
1863 $evalarg = $to_watch[$n];
1864 local $onetimeDump; # Tell DB::eval() to not output results
69893cff
RGS
1865
1866 # Fix context DB::eval() wants to return an array, but
1867 # we need a scalar here.
e22ea7cc
RF
1868 my ($val) = join( "', '", &eval );
1869 $val = ( ( defined $val ) ? "'$val'" : 'undef' );
69893cff
RGS
1870
1871 # Did it change?
e22ea7cc
RF
1872 if ( $val ne $old_watch[$n] ) {
1873
69893cff 1874 # Yep! Show the difference, and fake an interrupt.
e22ea7cc
RF
1875 $signal = 1;
1876 print $OUT <<EOP;
405ff068 1877Watchpoint $n:\t$to_watch[$n] changed:
69893cff
RGS
1878 old value:\t$old_watch[$n]
1879 new value:\t$val
6027b9a3 1880EOP
e22ea7cc 1881 $old_watch[$n] = $val;
69893cff 1882 } ## end if ($val ne $old_watch...
2c247e84 1883 } ## end for my $n (0 ..
69893cff
RGS
1884 } ## end if ($trace & 2)
1885
1886=head2 C<watchfunction()>
1887
1888C<watchfunction()> is a function that can be defined by the user; it is a
b570d64b 1889function which will be run on each entry to C<DB::DB>; it gets the
69893cff
RGS
1890current package, filename, and line as its parameters.
1891
b570d64b 1892The watchfunction can do anything it likes; it is executing in the
69893cff
RGS
1893debugger's context, so it has access to all of the debugger's internal
1894data structures and functions.
1895
1896C<watchfunction()> can control the debugger's actions. Any of the following
1897will cause the debugger to return control to the user's program after
1898C<watchfunction()> executes:
1899
b570d64b 1900=over 4
69893cff 1901
be9a9b1d
AT
1902=item *
1903
1904Returning a false value from the C<watchfunction()> itself.
1905
1906=item *
1907
1908Altering C<$single> to a false value.
1909
1910=item *
69893cff 1911
be9a9b1d 1912Altering C<$signal> to a false value.
69893cff 1913
be9a9b1d 1914=item *
69893cff 1915
be9a9b1d 1916Turning off the C<4> bit in C<$trace> (this also disables the
69893cff
RGS
1917check for C<watchfunction()>. This can be done with
1918
1919 $trace &= ~4;
1920
1921=back
1922
1923=cut
1924
e22ea7cc 1925 # If there's a user-defined DB::watchfunction, call it with the
69893cff
RGS
1926 # current package, filename, and line. The function executes in
1927 # the DB:: package.
e22ea7cc
RF
1928 if ( $trace & 4 ) { # User-installed watch
1929 return
1930 if watchfunction( $package, $filename, $line )
1931 and not $single
1932 and not $was_signal
1933 and not( $trace & ~4 );
69893cff
RGS
1934 } ## end if ($trace & 4)
1935
e22ea7cc 1936 # Pick up any alteration to $signal in the watchfunction, and
69893cff 1937 # turn off the signal now.
6027b9a3 1938 $was_signal = $signal;
69893cff
RGS
1939 $signal = 0;
1940
1941=head2 GETTING READY TO EXECUTE COMMANDS
1942
1943The debugger decides to take control if single-step mode is on, the
1944C<t> command was entered, or the user generated a signal. If the program
1945has fallen off the end, we set things up so that entering further commands
1946won't cause trouble, and we say that the program is over.
1947
1948=cut
1949
8dc67a69
SF
1950 # Make sure that we always print if asked for explicitly regardless
1951 # of $trace_to_depth .
1952 my $explicit_stop = ($single || $was_signal);
1953
69893cff
RGS
1954 # Check to see if we should grab control ($single true,
1955 # trace set appropriately, or we got a signal).
8dc67a69 1956 if ( $explicit_stop || ( $trace & 1 ) ) {
e22ea7cc 1957
69893cff 1958 # Yes, grab control.
e22ea7cc
RF
1959 if ($slave_editor) {
1960
69893cff 1961 # Tell the editor to update its position.
e22ea7cc
RF
1962 $position = "\032\032$filename:$line:0\n";
1963 print_lineinfo($position);
1964 }
69893cff
RGS
1965
1966=pod
1967
b570d64b 1968Special check: if we're in package C<DB::fake>, we've gone through the
69893cff
RGS
1969C<END> block at least once. We set up everything so that we can continue
1970to enter commands and have a valid context to be in.
1971
1972=cut
1973
e22ea7cc 1974 elsif ( $package eq 'DB::fake' ) {
69893cff 1975
69893cff 1976 # Fallen off the end already.
e22ea7cc
RF
1977 $term || &setterm;
1978 print_help(<<EOP);
405ff068 1979Debugged program terminated. Use B<q> to quit or B<R> to restart,
6b27b0a0 1980 use B<o> I<inhibit_exit> to avoid stopping after program termination,
b570d64b 1981 B<h q>, B<h R> or B<h o> to get additional info.
405ff068 1982EOP
e22ea7cc 1983
69893cff 1984 # Set the DB::eval context appropriately.
e22ea7cc 1985 $package = 'main';
6b24a4b7 1986 $usercontext = _calc_usercontext($package);
69893cff 1987 } ## end elsif ($package eq 'DB::fake')
e219e2fb 1988
69893cff 1989=pod
e219e2fb 1990
69893cff
RGS
1991If the program hasn't finished executing, we scan forward to the
1992next executable line, print that out, build the prompt from the file and line
b570d64b 1993number information, and print that.
e219e2fb 1994
69893cff
RGS
1995=cut
1996
e22ea7cc
RF
1997 else {
1998
8dc67a69 1999
69893cff
RGS
2000 # Still somewhere in the midst of execution. Set up the
2001 # debugger prompt.
2002 $sub =~ s/\'/::/; # Swap Perl 4 package separators (') to
e22ea7cc 2003 # Perl 5 ones (sorry, we don't print Klingon
69893cff
RGS
2004 #module names)
2005
6b24a4b7 2006 $prefix = $sub =~ /::/ ? "" : ($package . '::');
e22ea7cc
RF
2007 $prefix .= "$sub($filename:";
2008 $after = ( $dbline[$line] =~ /\n$/ ? '' : "\n" );
69893cff
RGS
2009
2010 # Break up the prompt if it's really long.
e22ea7cc
RF
2011 if ( length($prefix) > 30 ) {
2012 $position = "$prefix$line):\n$line:\t$dbline[$line]$after";
2013 $prefix = "";
2014 $infix = ":\t";
2015 }
2016 else {
2017 $infix = "):\t";
2018 $position = "$prefix$line$infix$dbline[$line]$after";
2019 }
69893cff
RGS
2020
2021 # Print current line info, indenting if necessary.
e22ea7cc
RF
2022 if ($frame) {
2023 print_lineinfo( ' ' x $stack_depth,
2024 "$line:\t$dbline[$line]$after" );
2025 }
2026 else {
8dc67a69 2027 depth_print_lineinfo($explicit_stop, $position);
e22ea7cc 2028 }
69893cff
RGS
2029
2030 # Scan forward, stopping at either the end or the next
2031 # unbreakable line.
72d7d80d 2032 for ( my $i = $line + 1 ; $i <= $max && $dbline[$i] == 0 ; ++$i )
e22ea7cc 2033 { #{ vi
69893cff
RGS
2034
2035 # Drop out on null statements, block closers, and comments.
2036 last if $dbline[$i] =~ /^\s*[\;\}\#\n]/;
2037
2038 # Drop out if the user interrupted us.
2039 last if $signal;
2040
2041 # Append a newline if the line doesn't have one. Can happen
2042 # in eval'ed text, for instance.
e22ea7cc 2043 $after = ( $dbline[$i] =~ /\n$/ ? '' : "\n" );
69893cff
RGS
2044
2045 # Next executable line.
6b24a4b7 2046 my $incr_pos = "$prefix$i$infix$dbline[$i]$after";
69893cff
RGS
2047 $position .= $incr_pos;
2048 if ($frame) {
e22ea7cc 2049
69893cff 2050 # Print it indented if tracing is on.
e22ea7cc
RF
2051 print_lineinfo( ' ' x $stack_depth,
2052 "$i:\t$dbline[$i]$after" );
69893cff
RGS
2053 }
2054 else {
8dc67a69 2055 depth_print_lineinfo($explicit_stop, $incr_pos);
69893cff 2056 }
72d7d80d 2057 } ## end for ($i = $line + 1 ; $i...
69893cff
RGS
2058 } ## end else [ if ($slave_editor)
2059 } ## end if ($single || ($trace...
2060
2061=pod
2062
2063If there's an action to be executed for the line we stopped at, execute it.
b570d64b 2064If there are any preprompt actions, execute those as well.
e219e2fb
RF
2065
2066=cut
2067
69893cff
RGS
2068 # If there's an action, do it now.
2069 $evalarg = $action, &eval if $action;
e219e2fb 2070
69893cff
RGS
2071 # Are we nested another level (e.g., did we evaluate a function
2072 # that had a breakpoint in it at the debugger prompt)?
e22ea7cc
RF
2073 if ( $single || $was_signal ) {
2074
69893cff 2075 # Yes, go down a level.
e22ea7cc 2076 local $level = $level + 1;
69893cff
RGS
2077
2078 # Do any pre-prompt actions.
e22ea7cc
RF
2079 foreach $evalarg (@$pre) {
2080 &eval;
2081 }
69893cff
RGS
2082
2083 # Complain about too much recursion if we passed the limit.
e22ea7cc 2084 print $OUT $stack_depth . " levels deep in subroutine calls!\n"
69893cff
RGS
2085 if $single & 4;
2086
2087 # The line we're currently on. Set $incr to -1 to stay here
2088 # until we get a command that tells us to advance.
e22ea7cc
RF
2089 $start = $line;
2090 $incr = -1; # for backward motion.
69893cff
RGS
2091
2092 # Tack preprompt debugger actions ahead of any actual input.
e22ea7cc 2093 @typeahead = ( @$pretype, @typeahead );
69893cff
RGS
2094
2095=head2 WHERE ARE WE?
2096
2097XXX Relocate this section?
2098
2099The debugger normally shows the line corresponding to the current line of
2100execution. Sometimes, though, we want to see the next line, or to move elsewhere
2101in the file. This is done via the C<$incr>, C<$start>, and C<$max> variables.
2102
be9a9b1d
AT
2103C<$incr> controls by how many lines the I<current> line should move forward
2104after a command is executed. If set to -1, this indicates that the I<current>
69893cff
RGS
2105line shouldn't change.
2106
be9a9b1d 2107C<$start> is the I<current> line. It is used for things like knowing where to
69893cff
RGS
2108move forwards or backwards from when doing an C<L> or C<-> command.
2109
2110C<$max> tells the debugger where the last line of the current file is. It's
2111used to terminate loops most often.
2112
2113=head2 THE COMMAND LOOP
2114
2115Most of C<DB::DB> is actually a command parsing and dispatch loop. It comes
2116in two parts:
2117
2118=over 4
2119
be9a9b1d
AT
2120=item *
2121
2122The outer part of the loop, starting at the C<CMD> label. This loop
69893cff
RGS
2123reads a command and then executes it.
2124
be9a9b1d
AT
2125=item *
2126
2127The inner part of the loop, starting at the C<PIPE> label. This part
69893cff
RGS
2128is wholly contained inside the C<CMD> block and only executes a command.
2129Used to handle commands running inside a pager.
2130
2131=back
2132
2133So why have two labels to restart the loop? Because sometimes, it's easier to
2134have a command I<generate> another command and then re-execute the loop to do
2135the new command. This is faster, but perhaps a bit more convoluted.
2136
2137=cut
2138
2139 # The big command dispatch loop. It keeps running until the
2140 # user yields up control again.
2141 #
2142 # If we have a terminal for input, and we get something back
2143 # from readline(), keep on processing.
6b24a4b7
SF
2144 my $piped;
2145 my $selected;
2146
e22ea7cc
RF
2147 CMD:
2148 while (
2149
69893cff 2150 # We have a terminal, or can get one ...
e22ea7cc
RF
2151 ( $term || &setterm ),
2152
69893cff 2153 # ... and it belogs to this PID or we get one for this PID ...
e22ea7cc
RF
2154 ( $term_pid == $$ or resetterm(1) ),
2155
69893cff 2156 # ... and we got a line of command input ...
e22ea7cc
RF
2157 defined(
2158 $cmd = &readline(
2cbb2ee1 2159 "$pidprompt $tid DB"
e22ea7cc
RF
2160 . ( '<' x $level )
2161 . ( $#hist + 1 )
2162 . ( '>' x $level ) . " "
69893cff
RGS
2163 )
2164 )
2165 )
2166 {
e22ea7cc 2167
2cbb2ee1 2168 share($cmd);
69893cff
RGS
2169 # ... try to execute the input as debugger commands.
2170
2171 # Don't stop running.
2172 $single = 0;
2173
2174 # No signal is active.
2175 $signal = 0;
2176
2177 # Handle continued commands (ending with \):
3d7a2a93 2178 if ($cmd =~ s/\\\z/\n/) {
e22ea7cc
RF
2179 $cmd .= &readline(" cont: ");
2180 redo CMD;
3d7a2a93 2181 }
69893cff
RGS
2182
2183=head4 The null command
2184
be9a9b1d 2185A newline entered by itself means I<re-execute the last command>. We grab the
69893cff
RGS
2186command out of C<$laststep> (where it was recorded previously), and copy it
2187back into C<$cmd> to be executed below. If there wasn't any previous command,
2188we'll do nothing below (no command will match). If there was, we also save it
2189in the command history and fall through to allow the command parsing to pick
2190it up.
2191
2192=cut
2193
2194 # Empty input means repeat the last command.
e22ea7cc
RF
2195 $cmd =~ /^$/ && ( $cmd = $laststep );
2196 chomp($cmd); # get rid of the annoying extra newline
2197 push( @hist, $cmd ) if length($cmd) > 1;
2198 push( @truehist, $cmd );
2cbb2ee1
RGS
2199 share(@hist);
2200 share(@truehist);
e22ea7cc
RF
2201
2202 # This is a restart point for commands that didn't arrive
2203 # via direct user input. It allows us to 'redo PIPE' to
2204 # re-execute command processing without reading a new command.
69893cff 2205 PIPE: {
e22ea7cc
RF
2206 $cmd =~ s/^\s+//s; # trim annoying leading whitespace
2207 $cmd =~ s/\s+$//s; # trim annoying trailing whitespace
6b24a4b7 2208 my ($i) = split( /\s+/, $cmd );
69893cff
RGS
2209
2210=head3 COMMAND ALIASES
2211
2212The debugger can create aliases for commands (these are stored in the
2213C<%alias> hash). Before a command is executed, the command loop looks it up
2214in the alias hash and substitutes the contents of the alias for the command,
2215completely replacing it.
2216
2217=cut
2218
2219 # See if there's an alias for the command, and set it up if so.
e22ea7cc
RF
2220 if ( $alias{$i} ) {
2221
69893cff
RGS
2222 # Squelch signal handling; we want to keep control here
2223 # if something goes loco during the alias eval.
2224 local $SIG{__DIE__};
2225 local $SIG{__WARN__};
2226
2227 # This is a command, so we eval it in the DEBUGGER's
2228 # scope! Otherwise, we can't see the special debugger
2229 # variables, or get to the debugger's subs. (Well, we
2230 # _could_, but why make it even more complicated?)
2231 eval "\$cmd =~ $alias{$i}";
2232 if ($@) {
2233 local $\ = '';
1f874cb6 2234 print $OUT "Couldn't evaluate '$i' alias: $@";
69893cff
RGS
2235 next CMD;
2236 }
2237 } ## end if ($alias{$i})
2238
2239=head3 MAIN-LINE COMMANDS
2240
2241All of these commands work up to and after the program being debugged has
b570d64b 2242terminated.
69893cff
RGS
2243
2244=head4 C<q> - quit
2245
b570d64b 2246Quit the debugger. This entails setting the C<$fall_off_end> flag, so we don't
69893cff
RGS
2247try to execute further, cleaning any restart-related stuff out of the
2248environment, and executing with the last value of C<$?>.
2249
2250=cut
2251
3d7a2a93 2252 if ($cmd eq 'q') {
69893cff
RGS
2253 $fall_off_end = 1;
2254 clean_ENV();
2255 exit $?;
3d7a2a93 2256 }
69893cff 2257
611272bb 2258=head4 C<t> - trace [n]
69893cff
RGS
2259
2260Turn tracing on or off. Inverts the appropriate bit in C<$trace> (q.v.).
611272bb 2261If level is specified, set C<$trace_to_depth>.
69893cff
RGS
2262
2263=cut
2264
3d7a2a93 2265 if (my ($levels) = $cmd =~ /\At(?:\s+(\d+))?\z/) {
e22ea7cc
RF
2266 $trace ^= 1;
2267 local $\ = '';
611272bb 2268 $trace_to_depth = $levels ? $stack_depth + $levels : 1E9;
e22ea7cc 2269 print $OUT "Trace = "
611272bb
PS
2270 . ( ( $trace & 1 )
2271 ? ( $levels ? "on (to level $trace_to_depth)" : "on" )
2272 : "off" ) . "\n";
e22ea7cc 2273 next CMD;
3d7a2a93 2274 }
69893cff
RGS
2275
2276=head4 C<S> - list subroutines matching/not matching a pattern
2277
2278Walks through C<%sub>, checking to see whether or not to print the name.
2279
2280=cut
2281
826b9a2e
SF
2282 if (my ($print_all_subs, $should_reverse, $Spatt)
2283 = $cmd =~ /\AS(\s+(!)?(.+))?\z/) {
2284 # $Spatt is the pattern (if any) to use.
2285 # Reverse scan?
2286 my $Srev = defined $should_reverse;
2287 # No args - print all subs.
2288 my $Snocheck = !defined $print_all_subs;
69893cff
RGS
2289
2290 # Need to make these sane here.
e22ea7cc
RF
2291 local $\ = '';
2292 local $, = '';
69893cff
RGS
2293
2294 # Search through the debugger's magical hash of subs.
2295 # If $nocheck is true, just print the sub name.
2296 # Otherwise, check it against the pattern. We then use
2297 # the XOR trick to reverse the condition as required.
e22ea7cc
RF
2298 foreach $subname ( sort( keys %sub ) ) {
2299 if ( $Snocheck or $Srev ^ ( $subname =~ /$Spatt/ ) ) {
2300 print $OUT $subname, "\n";
2301 }
2302 }
2303 next CMD;
826b9a2e 2304 }
69893cff
RGS
2305
2306=head4 C<X> - list variables in current package
2307
b570d64b 2308Since the C<V> command actually processes this, just change this to the
69893cff
RGS
2309appropriate C<V> command and fall through.
2310
2311=cut
2312
e22ea7cc 2313 $cmd =~ s/^X\b/V $package/;
69893cff
RGS
2314
2315=head4 C<V> - list variables
2316
b570d64b 2317Uses C<dumpvar.pl> to dump out the current values for selected variables.
69893cff
RGS
2318
2319=cut
2320
2321 # Bare V commands get the currently-being-debugged package
2322 # added.
826b9a2e 2323 if ($cmd eq "V") {
e22ea7cc 2324 $cmd = "V $package";
826b9a2e 2325 }
69893cff
RGS
2326
2327 # V - show variables in package.
826b9a2e
SF
2328 if (my ($new_packname, $new_vars_str) =
2329 $cmd =~ /\AV\b\s*(\S+)\s*(.*)/) {
e22ea7cc 2330
69893cff
RGS
2331 # Save the currently selected filehandle and
2332 # force output to debugger's filehandle (dumpvar
2333 # just does "print" for output).
6b24a4b7 2334 my $savout = select($OUT);
69893cff
RGS
2335
2336 # Grab package name and variables to dump.
826b9a2e
SF
2337 $packname = $new_packname;
2338 my @vars = split( ' ', $new_vars_str );
69893cff
RGS
2339
2340 # If main::dumpvar isn't here, get it.
e81465be 2341 do 'dumpvar.pl' || die $@ unless defined &main::dumpvar;
e22ea7cc
RF
2342 if ( defined &main::dumpvar ) {
2343
69893cff
RGS
2344 # We got it. Turn off subroutine entry/exit messages
2345 # for the moment, along with return values.
e22ea7cc
RF
2346 local $frame = 0;
2347 local $doret = -2;
69893cff
RGS
2348
2349 # must detect sigpipe failures - not catching
2350 # then will cause the debugger to die.
2351 eval {
2352 &main::dumpvar(
2353 $packname,
2354 defined $option{dumpDepth}
e22ea7cc
RF
2355 ? $option{dumpDepth}
2356 : -1, # assume -1 unless specified
69893cff 2357 @vars
e22ea7cc
RF
2358 );
2359 };
2360
2361 # The die doesn't need to include the $@, because
2362 # it will automatically get propagated for us.
2363 if ($@) {
2364 die unless $@ =~ /dumpvar print failed/;
2365 }
2366 } ## end if (defined &main::dumpvar)
2367 else {
2368
2369 # Couldn't load dumpvar.
2370 print $OUT "dumpvar.pl not available.\n";
2371 }
69893cff 2372
69893cff 2373 # Restore the output filehandle, and go round again.
e22ea7cc
RF
2374 select($savout);
2375 next CMD;
826b9a2e 2376 }
69893cff
RGS
2377
2378=head4 C<x> - evaluate and print an expression
2379
2380Hands the expression off to C<DB::eval>, setting it up to print the value
2381via C<dumpvar.pl> instead of just printing it directly.
2382
2383=cut
2384
826b9a2e 2385 if ($cmd =~ s#\Ax\b# #) { # Remainder gets done by DB::eval()
e22ea7cc 2386 $onetimeDump = 'dump'; # main::dumpvar shows the output
69893cff
RGS
2387
2388 # handle special "x 3 blah" syntax XXX propagate
2389 # doc back to special variables.
826b9a2e 2390 if ( $cmd =~ s#\A\s*(\d+)(?=\s)# #) {
e22ea7cc
RF
2391 $onetimedumpDepth = $1;
2392 }
826b9a2e 2393 }
69893cff
RGS
2394
2395=head4 C<m> - print methods
2396
2397Just uses C<DB::methods> to determine what methods are available.
2398
2399=cut
2400
826b9a2e 2401 if ($cmd =~ s#\Am\s+([\w:]+)\s*\z# #) {
e22ea7cc
RF
2402 methods($1);
2403 next CMD;
826b9a2e 2404 }
69893cff
RGS
2405
2406 # m expr - set up DB::eval to do the work
826b9a2e 2407 if ($cmd =~ s#\Am\b# #) { # Rest gets done by DB::eval()
e22ea7cc 2408 $onetimeDump = 'methods'; # method output gets used there
826b9a2e 2409 }
69893cff
RGS
2410
2411=head4 C<f> - switch files
2412
2413=cut
2414
826b9a2e 2415 if (($file) = $cmd =~ /\Af\b\s*(.*)/) {
e22ea7cc 2416 $file =~ s/\s+$//;
69893cff
RGS
2417
2418 # help for no arguments (old-style was return from sub).
e22ea7cc
RF
2419 if ( !$file ) {
2420 print $OUT
2421 "The old f command is now the r command.\n"; # hint
2422 print $OUT "The new f command switches filenames.\n";
2423 next CMD;
2424 } ## end if (!$file)
69893cff
RGS
2425
2426 # if not in magic file list, try a close match.
e22ea7cc
RF
2427 if ( !defined $main::{ '_<' . $file } ) {
2428 if ( ($try) = grep( m#^_<.*$file#, keys %main:: ) ) {
2429 {
2430 $try = substr( $try, 2 );
1f874cb6 2431 print $OUT "Choosing $try matching '$file':\n";
e22ea7cc
RF
2432 $file = $try;
2433 }
2434 } ## end if (($try) = grep(m#^_<.*$file#...
2435 } ## end if (!defined $main::{ ...
69893cff
RGS
2436
2437 # If not successfully switched now, we failed.
e22ea7cc 2438 if ( !defined $main::{ '_<' . $file } ) {
1f874cb6 2439 print $OUT "No file matching '$file' is loaded.\n";
e22ea7cc
RF
2440 next CMD;
2441 }
69893cff 2442
e22ea7cc
RF
2443 # We switched, so switch the debugger internals around.
2444 elsif ( $file ne $filename ) {
2445 *dbline = $main::{ '_<' . $file };
2446 $max = $#dbline;
2447 $filename = $file;
2448 $start = 1;
2449 $cmd = "l";
2450 } ## end elsif ($file ne $filename)
2451
2452 # We didn't switch; say we didn't.
2453 else {
2454 print $OUT "Already in $file.\n";
2455 next CMD;
2456 }
826b9a2e 2457 }
69893cff
RGS
2458
2459=head4 C<.> - return to last-executed line.
2460
2461We set C<$incr> to -1 to indicate that the debugger shouldn't move ahead,
2462and then we look up the line in the magical C<%dbline> hash.
2463
2464=cut
2465
2466 # . command.
826b9a2e 2467 if ($cmd eq '.') {
e22ea7cc 2468 $incr = -1; # stay at current line
69893cff
RGS
2469
2470 # Reset everything to the old location.
e22ea7cc
RF
2471 $start = $line;
2472 $filename = $filename_ini;
2473 *dbline = $main::{ '_<' . $filename };
2474 $max = $#dbline;
69893cff
RGS
2475
2476 # Now where are we?
e22ea7cc
RF
2477 print_lineinfo($position);
2478 next CMD;
826b9a2e 2479 }
69893cff
RGS
2480
2481=head4 C<-> - back one window
2482
2483We change C<$start> to be one window back; if we go back past the first line,
2484we set it to be the first line. We ser C<$incr> to put us back at the
2485currently-executing line, and then put a C<l $start +> (list one window from
2486C<$start>) in C<$cmd> to be executed later.
2487
2488=cut
2489
2490 # - - back a window.
826b9a2e 2491 if ($cmd eq '-') {
e22ea7cc 2492
69893cff 2493 # back up by a window; go to 1 if back too far.
e22ea7cc
RF
2494 $start -= $incr + $window + 1;
2495 $start = 1 if $start <= 0;
2496 $incr = $window - 1;
69893cff
RGS
2497
2498 # Generate and execute a "l +" command (handled below).
e22ea7cc 2499 $cmd = 'l ' . ($start) . '+';
826b9a2e 2500 }
69893cff
RGS
2501
2502=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>, {, {{>
2503
2504In Perl 5.8.0, a realignment of the commands was done to fix up a number of
2505problems, most notably that the default case of several commands destroying
2506the user's work in setting watchpoints, actions, etc. We wanted, however, to
2507retain the old commands for those who were used to using them or who preferred
2508them. At this point, we check for the new commands and call C<cmd_wrapper> to
2509deal with them instead of processing them in-line.
2510
2511=cut
2512
2513 # All of these commands were remapped in perl 5.8.0;
e22ea7cc 2514 # we send them off to the secondary dispatcher (see below).
826b9a2e
SF
2515 if (my ($cmd_letter, $my_arg) = $cmd =~ /\A([aAbBeEhilLMoOPvwW]\b|[<>\{]{1,2})\s*(.*)/so) {
2516 &cmd_wrapper( $cmd_letter, $my_arg, $line );
e22ea7cc 2517 next CMD;
826b9a2e 2518 }
69893cff
RGS
2519
2520=head4 C<y> - List lexicals in higher scope
2521
826b9a2e 2522Uses C<PadWalker> to find the lexicals supplied as arguments in a scope
69893cff
RGS
2523above the current one and then displays then using C<dumpvar.pl>.
2524
2525=cut
2526
826b9a2e
SF
2527 if (my ($match_level, $match_vars)
2528 = $cmd =~ /^y(?:\s+(\d*)\s*(.*))?$/) {
69893cff
RGS
2529
2530 # See if we've got the necessary support.
2531 eval { require PadWalker; PadWalker->VERSION(0.08) }
2532 or &warn(
2533 $@ =~ /locate/
2534 ? "PadWalker module not found - please install\n"
2535 : $@
2536 )
2537 and next CMD;
2538
2539 # Load up dumpvar if we don't have it. If we can, that is.
e81465be 2540 do 'dumpvar.pl' || die $@ unless defined &main::dumpvar;
69893cff
RGS
2541 defined &main::dumpvar
2542 or print $OUT "dumpvar.pl not available.\n"
2543 and next CMD;
2544
2545 # Got all the modules we need. Find them and print them.
826b9a2e 2546 my @vars = split( ' ', $match_vars || '' );
69893cff
RGS
2547
2548 # Find the pad.
826b9a2e 2549 my $h = eval { PadWalker::peek_my( ( $match_level || 0 ) + 1 ) };
69893cff
RGS
2550
2551 # Oops. Can't find it.
2552 $@ and $@ =~ s/ at .*//, &warn($@), next CMD;
2553
2554 # Show the desired vars with dumplex().
2555 my $savout = select($OUT);
2556
2557 # Have dumplex dump the lexicals.
e22ea7cc 2558 dumpvar::dumplex( $_, $h->{$_},
69893cff 2559 defined $option{dumpDepth} ? $option{dumpDepth} : -1,
e22ea7cc
RF
2560 @vars )
2561 for sort keys %$h;
69893cff
RGS
2562 select($savout);
2563 next CMD;
826b9a2e 2564 }
69893cff
RGS
2565
2566=head3 COMMANDS NOT WORKING AFTER PROGRAM ENDS
2567
2568All of the commands below this point don't work after the program being
2569debugged has ended. All of them check to see if the program has ended; this
2570allows the commands to be relocated without worrying about a 'line of
2571demarcation' above which commands can be entered anytime, and below which
2572they can't.
2573
2574=head4 C<n> - single step, but don't trace down into subs
2575
2576Done by setting C<$single> to 2, which forces subs to execute straight through
be9a9b1d 2577when entered (see C<DB::sub>). We also save the C<n> command in C<$laststep>,
826b9a2e 2578so a null command knows what to re-execute.
69893cff
RGS
2579
2580=cut
2581
e22ea7cc 2582 # n - next
826b9a2e 2583 if ($cmd eq 'n') {
69893cff 2584 end_report(), next CMD if $finished and $level <= 1;
e22ea7cc 2585
69893cff
RGS
2586 # Single step, but don't enter subs.
2587 $single = 2;
e22ea7cc 2588
69893cff 2589 # Save for empty command (repeat last).
e22ea7cc
RF
2590 $laststep = $cmd;
2591 last CMD;
826b9a2e 2592 }
69893cff
RGS
2593
2594=head4 C<s> - single-step, entering subs
2595
826b9a2e 2596Sets C<$single> to 1, which causes C<DB::sub> to continue tracing inside
69893cff
RGS
2597subs. Also saves C<s> as C<$lastcmd>.
2598
2599=cut
2600
2601 # s - single step.
826b9a2e 2602 if ($cmd eq 's') {
e22ea7cc 2603
69893cff
RGS
2604 # Get out and restart the command loop if program
2605 # has finished.
e22ea7cc
RF
2606 end_report(), next CMD if $finished and $level <= 1;
2607
69893cff 2608 # Single step should enter subs.
e22ea7cc
RF
2609 $single = 1;
2610
69893cff 2611 # Save for empty command (repeat last).
e22ea7cc
RF
2612 $laststep = $cmd;
2613 last CMD;
826b9a2e 2614 }
69893cff
RGS
2615
2616=head4 C<c> - run continuously, setting an optional breakpoint
2617
2618Most of the code for this command is taken up with locating the optional
2619breakpoint, which is either a subroutine name or a line number. We set
2620the appropriate one-time-break in C<@dbline> and then turn off single-stepping
2621in this and all call levels above this one.
2622
2623=cut
2624
2625 # c - start continuous execution.
ef18ae63 2626 if (($i) = $cmd =~ m#\Ac\b\s*([\w:]*)\s*\z#) {
e22ea7cc 2627
69893cff
RGS
2628 # Hey, show's over. The debugged program finished
2629 # executing already.
2630 end_report(), next CMD if $finished and $level <= 1;
2631
2632 # Capture the place to put a one-time break.
ef18ae63 2633 $subname = $i;
69893cff 2634
e22ea7cc
RF
2635 # Probably not needed, since we finish an interactive
2636 # sub-session anyway...
2637 # local $filename = $filename;
2638 # local *dbline = *dbline; # XXX Would this work?!
69893cff
RGS
2639 #
2640 # The above question wonders if localizing the alias
2641 # to the magic array works or not. Since it's commented
2642 # out, we'll just leave that to speculation for now.
2643
2644 # If the "subname" isn't all digits, we'll assume it
2645 # is a subroutine name, and try to find it.
e22ea7cc
RF
2646 if ( $subname =~ /\D/ ) { # subroutine name
2647 # Qualify it to the current package unless it's
2648 # already qualified.
69893cff
RGS
2649 $subname = $package . "::" . $subname
2650 unless $subname =~ /::/;
e22ea7cc 2651
69893cff
RGS
2652 # find_sub will return "file:line_number" corresponding
2653 # to where the subroutine is defined; we call find_sub,
e22ea7cc 2654 # break up the return value, and assign it in one
69893cff 2655 # operation.
e22ea7cc 2656 ( $file, $i ) = ( find_sub($subname) =~ /^(.*):(.*)$/ );
69893cff
RGS
2657
2658 # Force the line number to be numeric.
e22ea7cc 2659 $i += 0;
69893cff
RGS
2660
2661 # If we got a line number, we found the sub.
e22ea7cc
RF
2662 if ($i) {
2663
69893cff
RGS
2664 # Switch all the debugger's internals around so
2665 # we're actually working with that file.
e22ea7cc
RF
2666 $filename = $file;
2667 *dbline = $main::{ '_<' . $filename };
2668
69893cff 2669 # Mark that there's a breakpoint in this file.
e22ea7cc
RF
2670 $had_breakpoints{$filename} |= 1;
2671
69893cff
RGS
2672 # Scan forward to the first executable line
2673 # after the 'sub whatever' line.
e22ea7cc
RF
2674 $max = $#dbline;
2675 ++$i while $dbline[$i] == 0 && $i < $max;
2676 } ## end if ($i)
69893cff
RGS
2677
2678 # We didn't find a sub by that name.
e22ea7cc
RF
2679 else {
2680 print $OUT "Subroutine $subname not found.\n";
2681 next CMD;
2682 }
2683 } ## end if ($subname =~ /\D/)
69893cff
RGS
2684
2685 # At this point, either the subname was all digits (an
2686 # absolute line-break request) or we've scanned through
2687 # the code following the definition of the sub, looking
2688 # for an executable, which we may or may not have found.
2689 #
2690 # If $i (which we set $subname from) is non-zero, we
e22ea7cc
RF
2691 # got a request to break at some line somewhere. On
2692 # one hand, if there wasn't any real subroutine name
2693 # involved, this will be a request to break in the current
2694 # file at the specified line, so we have to check to make
69893cff
RGS
2695 # sure that the line specified really is breakable.
2696 #
2697 # On the other hand, if there was a subname supplied, the
3c4b39be 2698 # preceding block has moved us to the proper file and
69893cff
RGS
2699 # location within that file, and then scanned forward
2700 # looking for the next executable line. We have to make
2701 # sure that one was found.
2702 #
2703 # On the gripping hand, we can't do anything unless the
2704 # current value of $i points to a valid breakable line.
2705 # Check that.
e22ea7cc
RF
2706 if ($i) {
2707
69893cff 2708 # Breakable?
e22ea7cc
RF
2709 if ( $dbline[$i] == 0 ) {
2710 print $OUT "Line $i not breakable.\n";
2711 next CMD;
2712 }
2713
69893cff 2714 # Yes. Set up the one-time-break sigil.
e22ea7cc 2715 $dbline{$i} =~ s/($|\0)/;9$1/; # add one-time-only b.p.
5d5d9ea3 2716 _enable_breakpoint_temp_enabled_status($filename, $i);
e22ea7cc 2717 } ## end if ($i)
69893cff
RGS
2718
2719 # Turn off stack tracing from here up.
2c247e84
SF
2720 for my $i (0 .. $stack_depth) {
2721 $stack[ $i ] &= ~1;
e22ea7cc
RF
2722 }
2723 last CMD;
ef18ae63 2724 }
69893cff
RGS
2725
2726=head4 C<r> - return from a subroutine
2727
2728For C<r> to work properly, the debugger has to stop execution again
2729immediately after the return is executed. This is done by forcing
2730single-stepping to be on in the call level above the current one. If
2731we are printing return values when a C<r> is executed, set C<$doret>
2732appropriately, and force us out of the command loop.
2733
2734=cut
2735
2736 # r - return from the current subroutine.
ef18ae63 2737 if ($cmd eq 'r') {
e22ea7cc 2738
98dc9551 2739 # Can't do anything if the program's over.
e22ea7cc
RF
2740 end_report(), next CMD if $finished and $level <= 1;
2741
69893cff 2742 # Turn on stack trace.
e22ea7cc
RF
2743 $stack[$stack_depth] |= 1;
2744
69893cff 2745 # Print return value unless the stack is empty.
e22ea7cc
RF
2746 $doret = $option{PrintRet} ? $stack_depth - 1 : -2;
2747 last CMD;
ef18ae63 2748 }
69893cff 2749
69893cff
RGS
2750=head4 C<T> - stack trace
2751
2752Just calls C<DB::print_trace>.
2753
2754=cut
2755
ef18ae63 2756 if ($cmd eq 'T') {
e22ea7cc
RF
2757 print_trace( $OUT, 1 ); # skip DB
2758 next CMD;
ef18ae63 2759 }
69893cff
RGS
2760
2761=head4 C<w> - List window around current line.
2762
2763Just calls C<DB::cmd_w>.
2764
2765=cut
2766
ef18ae63
SF
2767 if (my ($arg) = $cmd =~ /\Aw\b\s*(.*)/s) {
2768 &cmd_w( 'w', $arg );
2769 next CMD;
2770 }
69893cff
RGS
2771
2772=head4 C<W> - watch-expression processing.
2773
b570d64b 2774Just calls C<DB::cmd_W>.
69893cff
RGS
2775
2776=cut
2777
ef18ae63
SF
2778 if (my ($arg) = $cmd =~ /\AW\b\s*(.*)/s) {
2779 &cmd_W( 'W', $arg );
2780 next CMD;
2781 }
69893cff
RGS
2782
2783=head4 C</> - search forward for a string in the source
2784
ef18ae63 2785We take the argument and treat it as a pattern. If it turns out to be a
69893cff 2786bad one, we return the error we got from trying to C<eval> it and exit.
ef18ae63 2787If not, we create some code to do the search and C<eval> it so it can't
69893cff
RGS
2788mess us up.
2789
2790=cut
2791
ef18ae63
SF
2792 # The pattern as a string.
2793 use vars qw($inpat);
69893cff 2794
ef18ae63 2795 if (($inpat) = $cmd =~ m#\A/(.*)\z#) {
69893cff
RGS
2796
2797 # Remove the final slash.
e22ea7cc 2798 $inpat =~ s:([^\\])/$:$1:;
69893cff
RGS
2799
2800 # If the pattern isn't null ...
e22ea7cc 2801 if ( $inpat ne "" ) {
69893cff
RGS
2802
2803 # Turn of warn and die procesing for a bit.
e22ea7cc
RF
2804 local $SIG{__DIE__};
2805 local $SIG{__WARN__};
69893cff
RGS
2806
2807 # Create the pattern.
e22ea7cc
RF
2808 eval '$inpat =~ m' . "\a$inpat\a";
2809 if ( $@ ne "" ) {
2810
69893cff 2811 # Oops. Bad pattern. No biscuit.
e22ea7cc 2812 # Print the eval error and go back for more
69893cff 2813 # commands.
e22ea7cc
RF
2814 print $OUT "$@";
2815 next CMD;
2816 }
2817 $pat = $inpat;
2818 } ## end if ($inpat ne "")
69893cff
RGS
2819
2820 # Set up to stop on wrap-around.
e22ea7cc 2821 $end = $start;
69893cff
RGS
2822
2823 # Don't move off the current line.
e22ea7cc 2824 $incr = -1;
69893cff
RGS
2825
2826 # Done in eval so nothing breaks if the pattern
2827 # does something weird.
e22ea7cc
RF
2828 eval '
2829 for (;;) {
69893cff 2830 # Move ahead one line.
e22ea7cc 2831 ++$start;
69893cff
RGS
2832
2833 # Wrap if we pass the last line.
e22ea7cc 2834 $start = 1 if ($start > $max);
69893cff
RGS
2835
2836 # Stop if we have gotten back to this line again,
e22ea7cc 2837 last if ($start == $end);
69893cff
RGS
2838
2839 # A hit! (Note, though, that we are doing
2840 # case-insensitive matching. Maybe a qr//
2841 # expression would be better, so the user could
2842 # do case-sensitive matching if desired.
e22ea7cc
RF
2843 if ($dbline[$start] =~ m' . "\a$pat\a" . 'i) {
2844 if ($slave_editor) {
69893cff 2845 # Handle proper escaping in the slave.
e22ea7cc 2846 print $OUT "\032\032$filename:$start:0\n";
b570d64b 2847 }
e22ea7cc 2848 else {
69893cff 2849 # Just print the line normally.
e22ea7cc
RF
2850 print $OUT "$start:\t",$dbline[$start],"\n";
2851 }
69893cff 2852 # And quit since we found something.
e22ea7cc
RF
2853 last;
2854 }
2855 } ';
2856
69893cff 2857 # If we wrapped, there never was a match.
e22ea7cc
RF
2858 print $OUT "/$pat/: not found\n" if ( $start == $end );
2859 next CMD;
ef18ae63 2860 }
69893cff
RGS
2861
2862=head4 C<?> - search backward for a string in the source
2863
2864Same as for C</>, except the loop runs backwards.
2865
2866=cut
2867
2868 # ? - backward pattern search.
ef18ae63 2869 if (my ($inpat) = $cmd =~ m#\A\?(.*)\z#) {
69893cff
RGS
2870
2871 # Get the pattern, remove trailing question mark.
e22ea7cc 2872 $inpat =~ s:([^\\])\?$:$1:;
69893cff
RGS
2873
2874 # If we've got one ...
e22ea7cc 2875 if ( $inpat ne "" ) {
69893cff
RGS
2876
2877 # Turn off die & warn handlers.
e22ea7cc
RF
2878 local $SIG{__DIE__};
2879 local $SIG{__WARN__};
2880 eval '$inpat =~ m' . "\a$inpat\a";
2881
2882 if ( $@ ne "" ) {
2883
69893cff 2884 # Ouch. Not good. Print the error.
e22ea7cc
RF
2885 print $OUT $@;
2886 next CMD;
2887 }
2888 $pat = $inpat;
69893cff 2889 } ## end if ($inpat ne "")
e22ea7cc 2890
69893cff 2891 # Where we are now is where to stop after wraparound.
e22ea7cc 2892 $end = $start;
69893cff
RGS
2893
2894 # Don't move away from this line.
e22ea7cc 2895 $incr = -1;
69893cff
RGS
2896
2897 # Search inside the eval to prevent pattern badness
2898 # from killing us.
e22ea7cc
RF
2899 eval '
2900 for (;;) {
69893cff 2901 # Back up a line.
e22ea7cc 2902 --$start;
69893cff
RGS
2903
2904 # Wrap if we pass the first line.
e22ea7cc
RF
2905
2906 $start = $max if ($start <= 0);
69893cff
RGS
2907
2908 # Quit if we get back where we started,
e22ea7cc 2909 last if ($start == $end);
69893cff
RGS
2910
2911 # Match?
e22ea7cc
RF
2912 if ($dbline[$start] =~ m' . "\a$pat\a" . 'i) {
2913 if ($slave_editor) {
69893cff 2914 # Yep, follow slave editor requirements.
e22ea7cc 2915 print $OUT "\032\032$filename:$start:0\n";
b570d64b 2916 }
e22ea7cc 2917 else {
69893cff 2918 # Yep, just print normally.
e22ea7cc
RF
2919 print $OUT "$start:\t",$dbline[$start],"\n";
2920 }
69893cff
RGS
2921
2922 # Found, so done.
e22ea7cc
RF
2923 last;
2924 }
2925 } ';
2926
2927 # Say we failed if the loop never found anything,
2928 print $OUT "?$pat?: not found\n" if ( $start == $end );
2929 next CMD;
ef18ae63 2930 }
69893cff
RGS
2931
2932=head4 C<$rc> - Recall command
2933
2934Manages the commands in C<@hist> (which is created if C<Term::ReadLine> reports
2935that the terminal supports history). It find the the command required, puts it
2936into C<$cmd>, and redoes the loop to execute it.
2937
2938=cut
2939
e22ea7cc 2940 # $rc - recall command.
ef18ae63 2941 if (my ($minus, $arg) = $cmd =~ m#\A$rc+\s*(-)?(\d+)?\z#) {
69893cff
RGS
2942
2943 # No arguments, take one thing off history.
e22ea7cc 2944 pop(@hist) if length($cmd) > 1;
69893cff 2945
e22ea7cc 2946 # Relative (- found)?
69893cff 2947 # Y - index back from most recent (by 1 if bare minus)
e22ea7cc 2948 # N - go to that particular command slot or the last
69893cff 2949 # thing if nothing following.
ef18ae63 2950 $i = $minus ? ( $#hist - ( $arg || 1 ) ) : ( $arg || $#hist );
69893cff
RGS
2951
2952 # Pick out the command desired.
e22ea7cc 2953 $cmd = $hist[$i];
69893cff
RGS
2954
2955 # Print the command to be executed and restart the loop
2956 # with that command in the buffer.
e22ea7cc
RF
2957 print $OUT $cmd, "\n";
2958 redo CMD;
ef18ae63 2959 }
69893cff
RGS
2960
2961=head4 C<$sh$sh> - C<system()> command
2962
2963Calls the C<DB::system()> to handle the command. This keeps the C<STDIN> and
2964C<STDOUT> from getting messed up.
2965
2966=cut
2967
2968 # $sh$sh - run a shell command (if it's all ASCII).
2969 # Can't run shell commands with Unicode in the debugger, hmm.
ef18ae63 2970 if (my ($arg) = $cmd =~ m#\A$sh$sh\s*(.*)#ms) {
e22ea7cc 2971
69893cff 2972 # System it.
ef18ae63 2973 &system($arg);
e22ea7cc 2974 next CMD;
ef18ae63 2975 }
69893cff
RGS
2976
2977=head4 C<$rc I<pattern> $rc> - Search command history
2978
2979Another command to manipulate C<@hist>: this one searches it with a pattern.
be9a9b1d 2980If a command is found, it is placed in C<$cmd> and executed via C<redo>.
69893cff
RGS
2981
2982=cut
2983
e22ea7cc 2984 # $rc pattern $rc - find a command in the history.
ef18ae63 2985 if (my ($arg) = $cmd =~ /\A$rc([^$rc].*)\z/) {
e22ea7cc 2986
69893cff 2987 # Create the pattern to use.
ef18ae63 2988 $pat = "^$arg";
69893cff
RGS
2989
2990 # Toss off last entry if length is >1 (and it always is).
e22ea7cc 2991 pop(@hist) if length($cmd) > 1;
69893cff
RGS
2992
2993 # Look backward through the history.
72d7d80d 2994 for ( $i = $#hist ; $i ; --$i ) {
69893cff 2995 # Stop if we find it.
e22ea7cc
RF
2996 last if $hist[$i] =~ /$pat/;
2997 }
2998
2999 if ( !$i ) {
69893cff 3000
69893cff 3001 # Never found it.
e22ea7cc
RF
3002 print $OUT "No such command!\n\n";
3003 next CMD;
3004 }
69893cff
RGS
3005
3006 # Found it. Put it in the buffer, print it, and process it.
e22ea7cc
RF
3007 $cmd = $hist[$i];
3008 print $OUT $cmd, "\n";
3009 redo CMD;
ef18ae63 3010 }
69893cff 3011
ef18ae63 3012=head4 C<$sh> - Invoke a shell
69893cff
RGS
3013
3014Uses C<DB::system> to invoke a shell.
3015
3016=cut
3017
3018 # $sh - start a shell.
ef18ae63 3019 if ($cmd =~ /\A$sh\z/) {
e22ea7cc 3020
69893cff
RGS
3021 # Run the user's shell. If none defined, run Bourne.
3022 # We resume execution when the shell terminates.
e22ea7cc
RF
3023 &system( $ENV{SHELL} || "/bin/sh" );
3024 next CMD;
ef18ae63 3025 }
69893cff
RGS
3026
3027=head4 C<$sh I<command>> - Force execution of a command in a shell
3028
3029Like the above, but the command is passed to the shell. Again, we use
3030C<DB::system> to avoid problems with C<STDIN> and C<STDOUT>.
3031
3032=cut
3033
3034 # $sh command - start a shell and run a command in it.
ef18ae63 3035 if (my ($arg) = $cmd =~ m#\A$sh\s*(.*)#ms) {
e22ea7cc
RF
3036
3037 # XXX: using csh or tcsh destroys sigint retvals!
3038 #&system($1); # use this instead
69893cff
RGS
3039
3040 # use the user's shell, or Bourne if none defined.
ef18ae63 3041 &system( $ENV{SHELL} || "/bin/sh", "-c", $arg );
e22ea7cc 3042 next CMD;
ef18ae63 3043 }
69893cff
RGS
3044
3045=head4 C<H> - display commands in history
3046
3047Prints the contents of C<@hist> (if any).
3048
3049=cut
3050
ef18ae63 3051 if ($cmd =~ /\AH\b\s*\*/) {
7fddc82f
RF
3052 @hist = @truehist = ();
3053 print $OUT "History cleansed\n";
3054 next CMD;
ef18ae63 3055 }
e22ea7cc 3056
ef18ae63
SF
3057 if (my ($num)
3058 = $cmd =~ /\AH\b\s*(?:-(\d+))?/) {
e22ea7cc
RF
3059
3060 # Anything other than negative numbers is ignored by
69893cff 3061 # the (incorrect) pattern, so this test does nothing.
ef18ae63 3062 $end = $num ? ( $#hist - $num ) : 0;
69893cff
RGS
3063
3064 # Set to the minimum if less than zero.
e22ea7cc 3065 $hist = 0 if $hist < 0;
69893cff 3066
e22ea7cc 3067 # Start at the end of the array.
69893cff
RGS
3068 # Stay in while we're still above the ending value.
3069 # Tick back by one each time around the loop.
72d7d80d 3070 for ( $i = $#hist ; $i > $end ; $i-- ) {
69893cff
RGS
3071
3072 # Print the command unless it has no arguments.
e22ea7cc
RF
3073 print $OUT "$i: ", $hist[$i], "\n"
3074 unless $hist[$i] =~ /^.?$/;
3075 }
3076 next CMD;
ef18ae63 3077 }
69893cff
RGS
3078
3079=head4 C<man, doc, perldoc> - look up documentation
3080
3081Just calls C<runman()> to print the appropriate document.
3082
3083=cut
3084
e22ea7cc 3085 # man, perldoc, doc - show manual pages.
ef18ae63
SF
3086 if (my ($man_page)
3087 = $cmd =~ /\A(?:man|(?:perl)?doc)\b(?:\s+([^(]*))?\z/) {
3088 runman($man_page);
e22ea7cc 3089 next CMD;
ef18ae63 3090 }
69893cff
RGS
3091
3092=head4 C<p> - print
3093
3094Builds a C<print EXPR> expression in the C<$cmd>; this will get executed at
3095the bottom of the loop.
3096
3097=cut
3098
ef18ae63 3099 my $print_cmd = 'print {$DB::OUT} ';
69893cff 3100 # p - print (no args): print $_.
ef18ae63
SF
3101 if ($cmd eq 'p') {
3102 $cmd = $print_cmd . '$_';
3103 }
69893cff
RGS
3104
3105 # p - print the given expression.
ef18ae63 3106 $cmd =~ s/\Ap\b/$print_cmd /;
69893cff
RGS
3107
3108=head4 C<=> - define command alias
3109
3110Manipulates C<%alias> to add or list command aliases.
3111
3112=cut
3113
e22ea7cc 3114 # = - set up a command alias.
ef18ae63 3115 if ($cmd =~ s/\A=\s*//) {
e22ea7cc
RF
3116 my @keys;
3117 if ( length $cmd == 0 ) {
3118
69893cff 3119 # No args, get current aliases.
e22ea7cc
RF
3120 @keys = sort keys %alias;
3121 }
3122 elsif ( my ( $k, $v ) = ( $cmd =~ /^(\S+)\s+(\S.*)/ ) ) {
3123
69893cff
RGS
3124 # Creating a new alias. $k is alias name, $v is
3125 # alias value.
3126
e22ea7cc
RF
3127 # can't use $_ or kill //g state
3128 for my $x ( $k, $v ) {
3129
3130 # Escape "alarm" characters.
3131 $x =~ s/\a/\\a/g;
3132 }
69893cff
RGS
3133
3134 # Substitute key for value, using alarm chars
e22ea7cc 3135 # as separators (which is why we escaped them in
69893cff 3136 # the command).
e22ea7cc 3137 $alias{$k} = "s\a$k\a$v\a";
69893cff
RGS
3138
3139 # Turn off standard warn and die behavior.
e22ea7cc
RF
3140 local $SIG{__DIE__};
3141 local $SIG{__WARN__};
69893cff
RGS
3142
3143 # Is it valid Perl?
e22ea7cc
RF
3144 unless ( eval "sub { s\a$k\a$v\a }; 1" ) {
3145
69893cff 3146 # Nope. Bad alias. Say so and get out.
e22ea7cc
RF
3147 print $OUT "Can't alias $k to $v: $@\n";
3148 delete $alias{$k};
3149 next CMD;
3150 }
3151
69893cff 3152 # We'll only list the new one.
e22ea7cc 3153 @keys = ($k);
69893cff
RGS
3154 } ## end elsif (my ($k, $v) = ($cmd...
3155
3156 # The argument is the alias to list.
e22ea7cc
RF
3157 else {
3158 @keys = ($cmd);
3159 }
69893cff
RGS
3160
3161 # List aliases.
e22ea7cc
RF
3162 for my $k (@keys) {
3163
98dc9551 3164 # Messy metaquoting: Trim the substitution code off.
69893cff
RGS
3165 # We use control-G as the delimiter because it's not
3166 # likely to appear in the alias.
e22ea7cc
RF
3167 if ( ( my $v = $alias{$k} ) =~ s\as\a$k\a(.*)\a$\a1\a ) {
3168
69893cff 3169 # Print the alias.
e22ea7cc
RF
3170 print $OUT "$k\t= $1\n";
3171 }
3172 elsif ( defined $alias{$k} ) {
3173
69893cff 3174 # Couldn't trim it off; just print the alias code.
e22ea7cc
RF
3175 print $OUT "$k\t$alias{$k}\n";
3176 }
3177 else {
3178
69893cff 3179 # No such, dude.
e22ea7cc
RF
3180 print "No alias for $k\n";
3181 }
69893cff 3182 } ## end for my $k (@keys)
e22ea7cc 3183 next CMD;
ef18ae63 3184 }
69893cff
RGS
3185
3186=head4 C<source> - read commands from a file.
3187
3188Opens a lexical filehandle and stacks it on C<@cmdfhs>; C<DB::readline> will
3189pick it up.
3190
3191=cut
3192
e22ea7cc 3193 # source - read commands from a file (or pipe!) and execute.
ef18ae63
SF
3194 if (my ($sourced_fn) = $cmd =~ /\Asource\s+(.*\S)/) {
3195 if ( open my $fh, $sourced_fn ) {
e22ea7cc 3196
69893cff 3197 # Opened OK; stick it in the list of file handles.
e22ea7cc
RF
3198 push @cmdfhs, $fh;
3199 }
3200 else {
3201
3202 # Couldn't open it.
ef18ae63 3203 &warn("Can't execute '$sourced_fn': $!\n");
e22ea7cc
RF
3204 }
3205 next CMD;
ef18ae63 3206 }
69893cff 3207
ef18ae63
SF
3208 if (my ($which_cmd, $position)
3209 = $cmd =~ /^(enable|disable)\s+(\S+)\s*$/) {
e09195af
SF
3210
3211 my ($fn, $line_num);
3212 if ($position =~ m{\A\d+\z})
3213 {
3214 $fn = $filename;
3215 $line_num = $position;
3216 }
ef18ae63
SF
3217 elsif (my ($new_fn, $new_line_num)
3218 = $position =~ m{\A(.*):(\d+)\z}) {
3219 ($fn, $line_num) = ($new_fn, $new_line_num);
e09195af
SF
3220 }
3221 else
3222 {
3223 &warn("Wrong spec for enable/disable argument.\n");
3224 }
3225
3226 if (defined($fn)) {
3227 if (_has_breakpoint_data_ref($fn, $line_num)) {
3228 _set_breakpoint_enabled_status($fn, $line_num,
ef18ae63 3229 ($which_cmd eq 'enable' ? 1 : '')
e09195af
SF
3230 );
3231 }
3232 else {
3233 &warn("No breakpoint set at ${fn}:${line_num}\n");
3234 }
3235 }
3236
3237 next CMD;
ef18ae63 3238 }
e09195af 3239
69893cff
RGS
3240=head4 C<save> - send current history to a file
3241
3242Takes the complete history, (not the shrunken version you see with C<H>),
3243and saves it to the given filename, so it can be replayed using C<source>.
3244
3245Note that all C<^(save|source)>'s are commented out with a view to minimise recursion.
3246
3247=cut
3248
3249 # save source - write commands to a file for later use
ef18ae63
SF
3250 if (my ($new_fn) = $cmd =~ /\Asave\s*(.*)\z/) {
3251 my $filename = $new_fn || '.perl5dbrc'; # default?
3252 if ( open my $fh, '>', $filename ) {
e22ea7cc
RF
3253
3254 # chomp to remove extraneous newlines from source'd files
3255 chomp( my @truelist =
3256 map { m/^\s*(save|source)/ ? "#$_" : $_ }
3257 @truehist );
3258 print $fh join( "\n", @truelist );
69893cff 3259 print "commands saved in $file\n";
e22ea7cc
RF
3260 }
3261 else {
ef18ae63 3262 &warn("Can't save debugger commands in '$new_fn': $!\n");
69893cff
RGS
3263 }
3264 next CMD;
ef18ae63 3265 }
69893cff 3266
7fddc82f
RF
3267=head4 C<R> - restart
3268
ef18ae63 3269Restart the debugger session.
7fddc82f
RF
3270
3271=head4 C<rerun> - rerun the current session
3272
3273Return to any given position in the B<true>-history list
3274
3275=cut
3276
3277 # R - restart execution.
3278 # rerun - controlled restart execution.
ff41e38d
SF
3279 if (my ($cmd_cmd, $cmd_params) =
3280 $cmd =~ /\A((?:R)|(?:rerun\s*(.*)))\z/) {
3281 my @args = ($cmd_cmd eq 'R' ? restart() : rerun($cmd_params));
7fddc82f 3282
ca28b541
AP
3283 # Close all non-system fds for a clean restart. A more
3284 # correct method would be to close all fds that were not
3285 # open when the process started, but this seems to be
3286 # hard. See "debugger 'R'estart and open database
3287 # connections" on p5p.
3288
47d3bbda 3289 my $max_fd = 1024; # default if POSIX can't be loaded
ca28b541 3290 if (eval { require POSIX }) {
5332cc68 3291 eval { $max_fd = POSIX::sysconf(POSIX::_SC_OPEN_MAX()) };
ca28b541
AP
3292 }
3293
3294 if (defined $max_fd) {
3295 foreach ($^F+1 .. $max_fd-1) {
3296 next unless open FD_TO_CLOSE, "<&=$_";
3297 close(FD_TO_CLOSE);
3298 }
3299 }
3300
7fddc82f
RF
3301 # And run Perl again. We use exec() to keep the
3302 # PID stable (and that way $ini_pids is still valid).
3303 exec(@args) || print $OUT "exec failed: $!\n";
3304
3305 last CMD;
ff41e38d 3306 }
7fddc82f 3307
69893cff
RGS
3308=head4 C<|, ||> - pipe output through the pager.
3309
be9a9b1d 3310For C<|>, we save C<OUT> (the debugger's output filehandle) and C<STDOUT>
69893cff
RGS
3311(the program's standard output). For C<||>, we only save C<OUT>. We open a
3312pipe to the pager (restoring the output filehandles if this fails). If this
b570d64b 3313is the C<|> command, we also set up a C<SIGPIPE> handler which will simply
69893cff
RGS
3314set C<$signal>, sending us back into the debugger.
3315
3316We then trim off the pipe symbols and C<redo> the command loop at the
3317C<PIPE> label, causing us to evaluate the command in C<$cmd> without
3318reading another.
3319
3320=cut
3321
3322 # || - run command in the pager, with output to DB::OUT.
ff41e38d 3323 if ($cmd =~ m#\A\|\|?\s*[^|]#) {
e22ea7cc
RF
3324 if ( $pager =~ /^\|/ ) {
3325
69893cff 3326 # Default pager is into a pipe. Redirect I/O.
e22ea7cc
RF
3327 open( SAVEOUT, ">&STDOUT" )
3328 || &warn("Can't save STDOUT");
3329 open( STDOUT, ">&OUT" )
3330 || &warn("Can't redirect STDOUT");
69893cff 3331 } ## end if ($pager =~ /^\|/)
e22ea7cc
RF
3332 else {
3333
69893cff 3334 # Not into a pipe. STDOUT is safe.
e22ea7cc
RF
3335 open( SAVEOUT, ">&OUT" ) || &warn("Can't save DB::OUT");
3336 }
69893cff
RGS
3337
3338 # Fix up environment to record we have less if so.
e22ea7cc
RF
3339 fix_less();
3340
3341 unless ( $piped = open( OUT, $pager ) ) {
69893cff 3342
69893cff 3343 # Couldn't open pipe to pager.
1f874cb6 3344 &warn("Can't pipe output to '$pager'");
e22ea7cc
RF
3345 if ( $pager =~ /^\|/ ) {
3346
69893cff 3347 # Redirect I/O back again.
e22ea7cc
RF
3348 open( OUT, ">&STDOUT" ) # XXX: lost message
3349 || &warn("Can't restore DB::OUT");
3350 open( STDOUT, ">&SAVEOUT" )
3351 || &warn("Can't restore STDOUT");
3352 close(SAVEOUT);
69893cff 3353 } ## end if ($pager =~ /^\|/)
e22ea7cc
RF
3354 else {
3355
69893cff 3356 # Redirect I/O. STDOUT already safe.
e22ea7cc
RF
3357 open( OUT, ">&STDOUT" ) # XXX: lost message
3358 || &warn("Can't restore DB::OUT");
3359 }
3360 next CMD;
69893cff
RGS
3361 } ## end unless ($piped = open(OUT,...
3362
3363 # Set up broken-pipe handler if necessary.
e22ea7cc
RF
3364 $SIG{PIPE} = \&DB::catch
3365 if $pager =~ /^\|/
3366 && ( "" eq $SIG{PIPE} || "DEFAULT" eq $SIG{PIPE} );
69893cff 3367
70c9432b
SF
3368 OUT->autoflush(1);
3369 # Save current filehandle, and put it back.
e22ea7cc 3370 $selected = select(OUT);
69893cff 3371 # Don't put it back if pager was a pipe.
e22ea7cc 3372 select($selected), $selected = "" unless $cmd =~ /^\|\|/;
69893cff
RGS
3373
3374 # Trim off the pipe symbols and run the command now.
ff41e38d 3375 $cmd =~ s#\A\|+\s*##;
e22ea7cc 3376 redo PIPE;
ff41e38d 3377 }
69893cff
RGS
3378
3379=head3 END OF COMMAND PARSING
3380
ff41e38d
SF
3381Anything left in C<$cmd> at this point is a Perl expression that we want to
3382evaluate. We'll always evaluate in the user's context, and fully qualify
69893cff
RGS
3383any variables we might want to address in the C<DB> package.
3384
3385=cut
3386
3387 # t - turn trace on.
ff41e38d
SF
3388 if ($cmd =~ s#\At\s+(\d+)?#\$DB::trace |= 1;\n#) {
3389 my $trace_arg = $1;
3390 $trace_to_depth = $trace_arg ? $stack_depth||0 + $1 : 1E9;
3391 }
69893cff
RGS
3392
3393 # s - single-step. Remember the last command was 's'.
ff41e38d
SF
3394 if ($cmd =~ s/\As\s/\$DB::single = 1;\n/) {
3395 $laststep = 's';
3396 }
69893cff
RGS
3397
3398 # n - single-step, but not into subs. Remember last command
e22ea7cc 3399 # was 'n'.
ff41e38d
SF
3400 if ($cmd =~ s#\An\s#\$DB::single = 2;\n#) {
3401 $laststep = 'n';
3402 }
69893cff 3403
e22ea7cc 3404 } # PIPE:
69893cff 3405
e22ea7cc 3406 # Make sure the flag that says "the debugger's running" is
69893cff 3407 # still on, to make sure we get control again.
e22ea7cc 3408 $evalarg = "\$^D = \$^D | \$DB::db_stop;\n$cmd";
69893cff
RGS
3409
3410 # Run *our* eval that executes in the caller's context.
e22ea7cc 3411 &eval;
69893cff
RGS
3412
3413 # Turn off the one-time-dump stuff now.
e22ea7cc
RF
3414 if ($onetimeDump) {
3415 $onetimeDump = undef;
69893cff 3416 $onetimedumpDepth = undef;
e22ea7cc
RF
3417 }
3418 elsif ( $term_pid == $$ ) {
c7e68384
IZ
3419 eval { # May run under miniperl, when not available...
3420 STDOUT->flush();
3421 STDERR->flush();
3422 };
e22ea7cc 3423
69893cff 3424 # XXX If this is the master pid, print a newline.
e22ea7cc
RF
3425 print $OUT "\n";
3426 }
3427 } ## end while (($term || &setterm...
69893cff
RGS
3428
3429=head3 POST-COMMAND PROCESSING
3430
3431After each command, we check to see if the command output was piped anywhere.
3432If so, we go through the necessary code to unhook the pipe and go back to
3433our standard filehandles for input and output.
3434
3435=cut
3436
e22ea7cc 3437 continue { # CMD:
69893cff
RGS
3438
3439 # At the end of every command:
e22ea7cc
RF
3440 if ($piped) {
3441
69893cff 3442 # Unhook the pipe mechanism now.
e22ea7cc
RF
3443 if ( $pager =~ /^\|/ ) {
3444
69893cff 3445 # No error from the child.
e22ea7cc 3446 $? = 0;
69893cff 3447
e22ea7cc
RF
3448 # we cannot warn here: the handle is missing --tchrist
3449 close(OUT) || print SAVEOUT "\nCan't close DB::OUT\n";
69893cff 3450
e22ea7cc 3451 # most of the $? crud was coping with broken cshisms
69893cff 3452 # $? is explicitly set to 0, so this never runs.
e22ea7cc 3453 if ($?) {
1f874cb6 3454 print SAVEOUT "Pager '$pager' failed: ";
e22ea7cc
RF
3455 if ( $? == -1 ) {
3456 print SAVEOUT "shell returned -1\n";
3457 }
3458 elsif ( $? >> 8 ) {
3459 print SAVEOUT ( $? & 127 )
3460 ? " (SIG#" . ( $? & 127 ) . ")"
3461 : "", ( $? & 128 ) ? " -- core dumped" : "", "\n";
3462 }
3463 else {
3464 print SAVEOUT "status ", ( $? >> 8 ), "\n";
3465 }
69893cff
RGS
3466 } ## end if ($?)
3467
e22ea7cc 3468 # Reopen filehandle for our output (if we can) and
69893cff 3469 # restore STDOUT (if we can).
e22ea7cc
RF
3470 open( OUT, ">&STDOUT" ) || &warn("Can't restore DB::OUT");
3471 open( STDOUT, ">&SAVEOUT" )
3472 || &warn("Can't restore STDOUT");
69893cff
RGS
3473
3474 # Turn off pipe exception handler if necessary.
e22ea7cc 3475 $SIG{PIPE} = "DEFAULT" if $SIG{PIPE} eq \&DB::catch;
69893cff 3476
e22ea7cc
RF
3477 # Will stop ignoring SIGPIPE if done like nohup(1)
3478 # does SIGINT but Perl doesn't give us a choice.
69893cff 3479 } ## end if ($pager =~ /^\|/)
e22ea7cc
RF
3480 else {
3481
69893cff 3482 # Non-piped "pager". Just restore STDOUT.
e22ea7cc
RF
3483 open( OUT, ">&SAVEOUT" ) || &warn("Can't restore DB::OUT");
3484 }
69893cff
RGS
3485
3486 # Close filehandle pager was using, restore the normal one
3487 # if necessary,
3488 close(SAVEOUT);
e22ea7cc 3489 select($selected), $selected = "" unless $selected eq "";
69893cff
RGS
3490
3491 # No pipes now.
e22ea7cc 3492 $piped = "";
69893cff 3493 } ## end if ($piped)
e22ea7cc 3494 } # CMD:
69893cff
RGS
3495
3496=head3 COMMAND LOOP TERMINATION
3497
3498When commands have finished executing, we come here. If the user closed the
3499input filehandle, we turn on C<$fall_off_end> to emulate a C<q> command. We
3500evaluate any post-prompt items. We restore C<$@>, C<$!>, C<$^E>, C<$,>, C<$/>,
3501C<$\>, and C<$^W>, and return a null list as expected by the Perl interpreter.
3502The interpreter will then execute the next line and then return control to us
3503again.
3504
3505=cut
3506
3507 # No more commands? Quit.
1f874cb6 3508 $fall_off_end = 1 unless defined $cmd; # Emulate 'q' on EOF
69893cff
RGS
3509
3510 # Evaluate post-prompt commands.
e22ea7cc
RF
3511 foreach $evalarg (@$post) {
3512 &eval;
3513 }
3514 } # if ($single || $signal)
69893cff
RGS
3515
3516 # Put the user's globals back where you found them.
e22ea7cc 3517 ( $@, $!, $^E, $,, $/, $\, $^W ) = @saved;
69893cff
RGS
3518 ();
3519} ## end sub DB
3520
3521# The following code may be executed now:
3522# BEGIN {warn 4}
3523
3524=head2 sub
3525
b570d64b 3526C<sub> is called whenever a subroutine call happens in the program being
69893cff
RGS
3527debugged. The variable C<$DB::sub> contains the name of the subroutine
3528being called.
3529
3530The core function of this subroutine is to actually call the sub in the proper
3531context, capturing its output. This of course causes C<DB::DB> to get called
3532again, repeating until the subroutine ends and returns control to C<DB::sub>
3533again. Once control returns, C<DB::sub> figures out whether or not to dump the
3534return value, and returns its captured copy of the return value as its own
3535return value. The value then feeds back into the program being debugged as if
3536C<DB::sub> hadn't been there at all.
3537
3538C<sub> does all the work of printing the subroutine entry and exit messages
3539enabled by setting C<$frame>. It notes what sub the autoloader got called for,
b570d64b 3540and also prints the return value if needed (for the C<r> command and if
69893cff
RGS
3541the 16 bit is set in C<$frame>).
3542
3543It also tracks the subroutine call depth by saving the current setting of
3544C<$single> in the C<@stack> package global; if this exceeds the value in
3545C<$deep>, C<sub> automatically turns on printing of the current depth by
be9a9b1d 3546setting the C<4> bit in C<$single>. In any case, it keeps the current setting
69893cff
RGS
3547of stop/don't stop on entry to subs set a