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e22ea7cc 1
b570d64b 2=head1 NAME
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be9a9b1d 4perl5db.pl - the perl debugger
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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
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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.
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38
39Unfortunately, though the variables are accessible, they're not well
40documented, so it's generally been a decision that hasn't made a lot of
41difference to most users. Where appropriate, comments have been added to
42make variables more accessible and usable, with the understanding that these
be9a9b1d 43I<are> debugger internals, and are therefore subject to change. Future
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44development should probably attempt to replace the globals with a well-defined
45API, but for now, the variables are what we've got.
46
47=head2 Automated variable stacking via C<local()>
48
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
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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
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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>,
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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<$@> is restored. This makes it simple (well, I<simpler>) to keep
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70track of C<$@> 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
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79like this:
80
81 # Find all non-'foo' subs:
b570d64b 82 S !/foo/
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83
84Boolean algebra states that the truth table for XOR looks like this:
85
86=over 4
87
b570d64b 88=item * 0 ^ 0 = 0
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89
90(! not present and no match) --> false, don't print
91
b570d64b 92=item * 0 ^ 1 = 1
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93
94(! not present and matches) --> true, print
95
b570d64b 96=item * 1 ^ 0 = 1
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97
98(! present and no match) --> true, print
99
b570d64b 100=item * 1 ^ 1 = 0
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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
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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<$frame>, have I<magical> values composed
69893cff 116of 1, 2, 4, etc. (powers of 2) OR'ed together. This allows several pieces
b570d64b 117of state to be stored independently in a single scalar.
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118
119A test like
120
121 if ($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
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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
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131it?
132
133=over 4
134
be9a9b1d 135=item *
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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
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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
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144works.
145
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146=item *
147
b570d64b 148Second, it's very easy to serialize a scalar number. This is done in
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149the restart code; the debugger state variables are saved in C<%ENV> and then
150restored when the debugger is restarted. Having them be just numbers makes
b570d64b 151this trivial.
69893cff 152
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153=item *
154
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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
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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
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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
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172
173There are a number of special data structures provided to the debugger by
174the Perl interpreter.
175
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176The array C<@{$main::{'_<'.$filename}}> (aliased locally to C<@dbline>
177via glob assignment) contains the text from C<$filename>, with each
178element corresponding to a single line of C<$filename>. Additionally,
179breakable lines will be dualvars with the numeric component being the
180memory address of a COP node. Non-breakable lines are dualvar to 0.
69893cff 181
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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$action>.
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187Values are magical in numeric context: 1 if the line is breakable, 0 if not.
188
ef18ae63 189The scalar C<${"_<$filename"}> simply contains the string C<<< _<$filename> >>>.
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190This is also the case for evaluated strings that contain subroutines, or
191which are currently being executed. The $filename for C<eval>ed strings looks
d24ca0c5 192like C<(eval 34).
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193
194=head1 DEBUGGER STARTUP
195
196When C<perl5db.pl> starts, it reads an rcfile (C<perl5db.ini> for
197non-interactive sessions, C<.perldb> for interactive ones) that can set a number
198of options. In addition, this file may define a subroutine C<&afterinit>
b570d64b 199that will be executed (in the debugger's context) after the debugger has
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200initialized itself.
201
b570d64b 202Next, it checks the C<PERLDB_OPTS> environment variable and treats its
be9a9b1d 203contents as the argument of a C<o> command in the debugger.
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204
205=head2 STARTUP-ONLY OPTIONS
206
207The following options can only be specified at startup.
208To set them in your rcfile, add a call to
209C<&parse_options("optionName=new_value")>.
210
211=over 4
212
b570d64b 213=item * TTY
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214
215the TTY to use for debugging i/o.
216
b570d64b 217=item * noTTY
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218
219if set, goes in NonStop mode. On interrupt, if TTY is not set,
b0e77abc 220uses the value of noTTY or F<$HOME/.perldbtty$$> to find TTY using
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221Term::Rendezvous. Current variant is to have the name of TTY in this
222file.
223
b570d64b 224=item * ReadLine
69893cff 225
5561b870 226if false, a dummy ReadLine is used, so you can debug
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227ReadLine applications.
228
b570d64b 229=item * NonStop
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230
231if true, no i/o is performed until interrupt.
232
b570d64b 233=item * LineInfo
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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
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239
240host:port to connect to on remote host for remote debugging.
241
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242=item * HistFile
243
244file to store session history to. There is no default and so no
245history file is written unless this variable is explicitly set.
246
247=item * HistSize
248
249number of commands to store to the file specified in C<HistFile>.
250Default is 100.
251
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252=back
253
254=head3 SAMPLE RCFILE
255
256 &parse_options("NonStop=1 LineInfo=db.out");
257 sub afterinit { $trace = 1; }
258
259The script will run without human intervention, putting trace
260information into C<db.out>. (If you interrupt it, you had better
be9a9b1d 261reset C<LineInfo> to something I<interactive>!)
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262
263=head1 INTERNALS DESCRIPTION
264
265=head2 DEBUGGER INTERFACE VARIABLES
266
267Perl supplies the values for C<%sub>. It effectively inserts
be9a9b1d 268a C<&DB::DB();> in front of each place that can have a
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269breakpoint. At each subroutine call, it calls C<&DB::sub> with
270C<$DB::sub> set to the called subroutine. It also inserts a C<BEGIN
271{require 'perl5db.pl'}> before the first line.
272
273After each C<require>d file is compiled, but before it is executed, a
274call to C<&DB::postponed($main::{'_<'.$filename})> is done. C<$filename>
275is the expanded name of the C<require>d file (as found via C<%INC>).
276
277=head3 IMPORTANT INTERNAL VARIABLES
278
279=head4 C<$CreateTTY>
280
281Used to control when the debugger will attempt to acquire another TTY to be
b570d64b 282used for input.
69893cff 283
b570d64b 284=over
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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.
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308
309=over 4
310
311=item * 0 - No enter/exit messages
312
be9a9b1d 313=item * 1 - Print I<entering> messages on subroutine entry
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314
315=item * 2 - Adds exit messages on subroutine exit. If no other flag is on, acts like 1+2.
316
be9a9b1d 317=item * 4 - Extended messages: C<< <in|out> I<context>=I<fully-qualified sub name> from I<file>:I<line> >>. If no other flag is on, acts like 1+4.
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318
319=item * 8 - Adds parameter information to messages, and overloaded stringify and tied FETCH is enabled on the printed arguments. Ignored if C<4> is not on.
320
321=item * 16 - Adds C<I<context> return from I<subname>: I<value>> messages on subroutine/eval exit. Ignored if C<4> is is not on.
322
323=back
324
be9a9b1d 325To get everything, use C<$frame=30> (or C<o f=30> as a debugger command).
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326The debugger internally juggles the value of C<$frame> during execution to
327protect external modules that the debugger uses from getting traced.
328
329=head4 C<$level>
330
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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
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333outputs a prompt. Also used to help determine if the program has finished
334during command parsing.
335
336=head4 C<$onetimeDump>
337
338Controls what (if anything) C<DB::eval()> will print after evaluating an
339expression.
340
341=over 4
342
343=item * C<undef> - don't print anything
344
345=item * C<dump> - use C<dumpvar.pl> to display the value returned
346
347=item * C<methods> - print the methods callable on the first item returned
348
349=back
350
351=head4 C<$onetimeDumpDepth>
352
be9a9b1d 353Controls how far down C<dumpvar.pl> will go before printing C<...> while
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354dumping a structure. Numeric. If C<undef>, print all levels.
355
356=head4 C<$signal>
357
358Used to track whether or not an C<INT> signal has been detected. C<DB::DB()>,
359which is called before every statement, checks this and puts the user into
360command mode if it finds C<$signal> set to a true value.
361
362=head4 C<$single>
363
364Controls behavior during single-stepping. Stacked in C<@stack> on entry to
365each subroutine; popped again at the end of each subroutine.
366
b570d64b 367=over 4
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368
369=item * 0 - run continuously.
370
be9a9b1d 371=item * 1 - single-step, go into subs. The C<s> command.
69893cff 372
be9a9b1d 373=item * 2 - single-step, don't go into subs. The C<n> command.
69893cff 374
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375=item * 4 - print current sub depth (turned on to force this when C<too much
376recursion> occurs.
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377
378=back
379
380=head4 C<$trace>
381
b570d64b 382Controls the output of trace information.
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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}}> ,
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406supplied by the Perl interpreter to the debugger. Contains the source.
407
408=head4 C<@old_watch>
409
410Previous values of watch expressions. First set when the expression is
411entered; reset whenever the watch expression changes.
412
413=head4 C<@saved>
414
415Saves important globals (C<$@>, C<$!>, C<$^E>, C<$,>, C<$/>, C<$\>, C<$^W>)
416so that the debugger can substitute safe values while it's running, and
417restore them when it returns control.
418
419=head4 C<@stack>
420
421Saves the current value of C<$single> on entry to a subroutine.
422Manipulated by the C<c> command to turn off tracing in all subs above the
423current one.
424
425=head4 C<@to_watch>
426
427The 'watch' expressions: to be evaluated before each line is executed.
428
429=head4 C<@typeahead>
430
431The typeahead buffer, used by C<DB::readline>.
432
433=head4 C<%alias>
434
435Command aliases. Stored as character strings to be substituted for a command
436entered.
437
438=head4 C<%break_on_load>
439
440Keys are file names, values are 1 (break when this file is loaded) or undef
441(don't break when it is loaded).
442
443=head4 C<%dbline>
444
be9a9b1d 445Keys are line numbers, values are C<condition\0action>. If used in numeric
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446context, values are 0 if not breakable, 1 if breakable, no matter what is
447in the actual hash entry.
448
449=head4 C<%had_breakpoints>
450
451Keys are file names; values are bitfields:
452
b570d64b 453=over 4
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454
455=item * 1 - file has a breakpoint in it.
456
457=item * 2 - file has an action in it.
458
459=back
460
461A zero or undefined value means this file has neither.
462
463=head4 C<%option>
464
465Stores the debugger options. These are character string values.
466
467=head4 C<%postponed>
468
469Saves breakpoints for code that hasn't been compiled yet.
470Keys are subroutine names, values are:
471
472=over 4
473
be9a9b1d 474=item * C<compile> - break when this sub is compiled
69893cff 475
be9a9b1d 476=item * C<< break +0 if <condition> >> - break (conditionally) at the start of this routine. The condition will be '1' if no condition was specified.
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477
478=back
479
480=head4 C<%postponed_file>
481
482This hash keeps track of breakpoints that need to be set for files that have
483not yet been compiled. Keys are filenames; values are references to hashes.
484Each of these hashes is keyed by line number, and its values are breakpoint
be9a9b1d 485definitions (C<condition\0action>).
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486
487=head1 DEBUGGER INITIALIZATION
488
489The debugger's initialization actually jumps all over the place inside this
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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
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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.
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504
505We'll detail the second C<BEGIN> block later; just remember that if you need
506to initialize something before the debugger starts really executing, that's
507where it has to go.
508
509=cut
510
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511package DB;
512
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513use strict;
514
2dbd01ad 515BEGIN {eval 'use IO::Handle'}; # Needed for flush only? breaks under miniperl
9eba6a4e 516
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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:
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524use vars qw($VERSION $header);
525
931d9438 526$VERSION = '1.39_05';
69893cff 527
e22ea7cc 528$header = "perl5db.pl version $VERSION";
d338d6fe 529
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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
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538C<$DB::evalarg>; this is done to avoid fiddling with the contents of C<@_>.
539
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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>.
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546
547Next we need to handle C<$@> without getting confused. We save C<$@> in a
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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
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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
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556(the "watch expressions" code does this to get the value of the watch
557expression but not show it unless it matters).
558
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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
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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.
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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
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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
6b24a4b7 638 $filename
6b24a4b7
SF
639 $hist
640 $histfile
641 $histsize
6b24a4b7
SF
642 $IN
643 $inhibit_exit
644 @ini_INC
645 $ini_warn
6b24a4b7
SF
646 $maxtrace
647 $od
6b24a4b7 648 $onetimedumpDepth
6b24a4b7
SF
649 @options
650 $osingle
651 $otrace
6b24a4b7
SF
652 $pager
653 $post
654 %postponed
655 $prc
656 $pre
657 $pretype
658 $psh
659 @RememberOnROptions
660 $remoteport
661 @res
662 $rl
663 @saved
6b24a4b7 664 $signalLevel
6b24a4b7 665 $sub
6b24a4b7 666 $term
6b24a4b7
SF
667 $usercontext
668 $warnLevel
6b24a4b7
SF
669);
670
0b83f3d9
SF
671our (
672 $evalarg,
673 $frame,
674 $ImmediateStop,
675 $line,
676 $onetimeDump,
1ce985d2 677 %option,
0b83f3d9 678 $OUT,
1ce985d2 679 $packname,
0b83f3d9
SF
680 $signal,
681 $single,
d1450c23 682 $start,
9d0b71b3
SF
683 %sub,
684 $subname,
0b83f3d9 685 $trace,
d1450c23 686 $window,
18b5b545 687);
931ac036 688
6b24a4b7
SF
689# Used to save @ARGV and extract any debugger-related flags.
690use vars qw(@ARGS);
691
692# Used to prevent multiple entries to diesignal()
693# (if for instance diesignal() itself dies)
694use vars qw($panic);
695
696# Used to prevent the debugger from running nonstop
697# after a restart
ebd0282e 698our ($second_time);
6b24a4b7
SF
699
700sub _calc_usercontext {
701 my ($package) = @_;
702
703 # Cancel strict completely for the evaluated code, so the code
704 # the user evaluates won't be affected by it. (Shlomi Fish)
22fc883d 705 return 'no strict; ($@, $!, $^E, $,, $/, $\, $^W) = @DB::saved;'
6b24a4b7
SF
706 . "package $package;"; # this won't let them modify, alas
707}
708
c1051fcf 709sub eval {
69893cff 710
c1051fcf 711 # 'my' would make it visible from user code
e22ea7cc 712 # but so does local! --tchrist
69893cff 713 # Remember: this localizes @DB::res, not @main::res.
c1051fcf
IZ
714 local @res;
715 {
e22ea7cc
RF
716
717 # Try to keep the user code from messing with us. Save these so that
718 # even if the eval'ed code changes them, we can put them back again.
719 # Needed because the user could refer directly to the debugger's
69893cff
RGS
720 # package globals (and any 'my' variables in this containing scope)
721 # inside the eval(), and we want to try to stay safe.
e22ea7cc 722 local $otrace = $trace;
69893cff
RGS
723 local $osingle = $single;
724 local $od = $^D;
725
726 # Untaint the incoming eval() argument.
727 { ($evalarg) = $evalarg =~ /(.*)/s; }
728
e22ea7cc 729 # $usercontext built in DB::DB near the comment
69893cff
RGS
730 # "set up the context for DB::eval ..."
731 # Evaluate and save any results.
e22ea7cc 732 @res = eval "$usercontext $evalarg;\n"; # '\n' for nice recursive debug
69893cff
RGS
733
734 # Restore those old values.
735 $trace = $otrace;
736 $single = $osingle;
737 $^D = $od;
c1051fcf 738 }
69893cff
RGS
739
740 # Save the current value of $@, and preserve it in the debugger's copy
741 # of the saved precious globals.
c1051fcf 742 my $at = $@;
69893cff
RGS
743
744 # Since we're only saving $@, we only have to localize the array element
745 # that it will be stored in.
e22ea7cc 746 local $saved[0]; # Preserve the old value of $@
7c54f46a 747 eval { DB::save() };
69893cff
RGS
748
749 # Now see whether we need to report an error back to the user.
c1051fcf 750 if ($at) {
69893cff
RGS
751 local $\ = '';
752 print $OUT $at;
753 }
754
755 # Display as required by the caller. $onetimeDump and $onetimedumpDepth
756 # are package globals.
757 elsif ($onetimeDump) {
e22ea7cc
RF
758 if ( $onetimeDump eq 'dump' ) {
759 local $option{dumpDepth} = $onetimedumpDepth
760 if defined $onetimedumpDepth;
761 dumpit( $OUT, \@res );
762 }
763 elsif ( $onetimeDump eq 'methods' ) {
764 methods( $res[0] );
765 }
69893cff 766 } ## end elsif ($onetimeDump)
c1051fcf 767 @res;
69893cff
RGS
768} ## end sub eval
769
770############################################## End lexical danger zone
c1051fcf 771
e22ea7cc
RF
772# After this point it is safe to introduce lexicals.
773# The code being debugged will be executing in its own context, and
69893cff 774# can't see the inside of the debugger.
d338d6fe 775#
e22ea7cc 776# However, one should not overdo it: leave as much control from outside as
69893cff
RGS
777# possible. If you make something a lexical, it's not going to be addressable
778# from outside the debugger even if you know its name.
779
d338d6fe
PP
780# This file is automatically included if you do perl -d.
781# It's probably not useful to include this yourself.
782#
e22ea7cc 783# Before venturing further into these twisty passages, it is
2f7e9187
MS
784# wise to read the perldebguts man page or risk the ire of dragons.
785#
69893cff
RGS
786# (It should be noted that perldebguts will tell you a lot about
787# the underlying mechanics of how the debugger interfaces into the
788# Perl interpreter, but not a lot about the debugger itself. The new
789# comments in this code try to address this problem.)
790
d338d6fe 791# Note that no subroutine call is possible until &DB::sub is defined
36477c24 792# (for subroutines defined outside of the package DB). In fact the same is
d338d6fe 793# true if $deep is not defined.
055fd3a9
GS
794
795# Enhanced by ilya@math.ohio-state.edu (Ilya Zakharevich)
055fd3a9
GS
796
797# modified Perl debugger, to be run from Emacs in perldb-mode
798# Ray Lischner (uunet!mntgfx!lisch) as of 5 Nov 1990
799# Johan Vromans -- upgrade to 4.0 pl 10
800# Ilya Zakharevich -- patches after 5.001 (and some before ;-)
6fae1ad7 801########################################################################
d338d6fe 802
69893cff
RGS
803=head1 DEBUGGER INITIALIZATION
804
805The debugger starts up in phases.
806
807=head2 BASIC SETUP
808
809First, it initializes the environment it wants to run in: turning off
810warnings during its own compilation, defining variables which it will need
811to avoid warnings later, setting itself up to not exit when the program
812terminates, and defaulting to printing return values for the C<r> command.
813
814=cut
815
eda6e075 816# Needed for the statement after exec():
69893cff
RGS
817#
818# This BEGIN block is simply used to switch off warnings during debugger
98dc9551 819# compilation. Probably it would be better practice to fix the warnings,
69893cff 820# but this is how it's done at the moment.
eda6e075 821
e22ea7cc
RF
822BEGIN {
823 $ini_warn = $^W;
824 $^W = 0;
825} # Switch compilation warnings off until another BEGIN.
d12a4851 826
69893cff
RGS
827local ($^W) = 0; # Switch run-time warnings off during init.
828
2cbb2ee1
RGS
829=head2 THREADS SUPPORT
830
831If we are running under a threaded Perl, we require threads and threads::shared
832if the environment variable C<PERL5DB_THREADED> is set, to enable proper
833threaded debugger control. C<-dt> can also be used to set this.
834
835Each new thread will be announced and the debugger prompt will always inform
836you of each new thread created. It will also indicate the thread id in which
837we are currently running within the prompt like this:
838
2dbd01ad 839 [tid] DB<$i>
2cbb2ee1
RGS
840
841Where C<[tid]> is an integer thread id and C<$i> is the familiar debugger
842command prompt. The prompt will show: C<[0]> when running under threads, but
843not actually in a thread. C<[tid]> is consistent with C<gdb> usage.
844
845While running under threads, when you set or delete a breakpoint (etc.), this
b570d64b 846will apply to all threads, not just the currently running one. When you are
2cbb2ee1
RGS
847in a currently executing thread, you will stay there until it completes. With
848the current implementation it is not currently possible to hop from one thread
849to another.
850
851The C<e> and C<E> commands are currently fairly minimal - see C<h e> and C<h E>.
852
853Note that threading support was built into the debugger as of Perl version
854C<5.8.6> and debugger version C<1.2.8>.
855
856=cut
857
858BEGIN {
2dbd01ad
SF
859 # ensure we can share our non-threaded variables or no-op
860 if ($ENV{PERL5DB_THREADED}) {
861 require threads;
862 require threads::shared;
863 import threads::shared qw(share);
864 $DBGR;
865 share(\$DBGR);
866 lock($DBGR);
867 print "Threads support enabled\n";
868 } else {
869 *lock = sub(*) {};
870 *share = sub(*) {};
871 }
2cbb2ee1
RGS
872}
873
2218c045
SF
874# These variables control the execution of 'dumpvar.pl'.
875{
876 package dumpvar;
877 use vars qw(
878 $hashDepth
879 $arrayDepth
880 $dumpDBFiles
881 $dumpPackages
882 $quoteHighBit
883 $printUndef
884 $globPrint
885 $usageOnly
886 );
887}
69893cff 888
2218c045
SF
889# used to control die() reporting in diesignal()
890{
891 package Carp;
892 use vars qw($CarpLevel);
893}
d338d6fe 894
422c59bf 895# without threads, $filename is not defined until DB::DB is called
2cbb2ee1 896foreach my $k (keys (%INC)) {
2dbd01ad 897 share(\$main::{'_<'.$filename}) if defined $filename;
2cbb2ee1
RGS
898};
899
54d04a52 900# Command-line + PERLLIB:
69893cff 901# Save the contents of @INC before they are modified elsewhere.
54d04a52
IZ
902@ini_INC = @INC;
903
69893cff
RGS
904# This was an attempt to clear out the previous values of various
905# trapped errors. Apparently it didn't help. XXX More info needed!
d338d6fe
PP
906# $prevwarn = $prevdie = $prevbus = $prevsegv = ''; # Does not help?!
907
69893cff
RGS
908# We set these variables to safe values. We don't want to blindly turn
909# off warnings, because other packages may still want them.
e22ea7cc
RF
910$trace = $signal = $single = 0; # Uninitialized warning suppression
911 # (local $^W cannot help - other packages!).
69893cff
RGS
912
913# Default to not exiting when program finishes; print the return
914# value when the 'r' command is used to return from a subroutine.
55497cff 915$inhibit_exit = $option{PrintRet} = 1;
d338d6fe 916
6b24a4b7
SF
917use vars qw($trace_to_depth);
918
5e2b42dd
SF
919# Default to 1E9 so it won't be limited to a certain recursion depth.
920$trace_to_depth = 1E9;
bdba49ad 921
69893cff
RGS
922=head1 OPTION PROCESSING
923
b570d64b
SF
924The debugger's options are actually spread out over the debugger itself and
925C<dumpvar.pl>; some of these are variables to be set, while others are
69893cff
RGS
926subs to be called with a value. To try to make this a little easier to
927manage, the debugger uses a few data structures to define what options
928are legal and how they are to be processed.
929
930First, the C<@options> array defines the I<names> of all the options that
931are to be accepted.
932
933=cut
934
935@options = qw(
5561b870 936 CommandSet HistFile HistSize
e22ea7cc
RF
937 hashDepth arrayDepth dumpDepth
938 DumpDBFiles DumpPackages DumpReused
939 compactDump veryCompact quote
940 HighBit undefPrint globPrint
941 PrintRet UsageOnly frame
942 AutoTrace TTY noTTY
943 ReadLine NonStop LineInfo
944 maxTraceLen recallCommand ShellBang
945 pager tkRunning ornaments
946 signalLevel warnLevel dieLevel
947 inhibit_exit ImmediateStop bareStringify
948 CreateTTY RemotePort windowSize
584420f0 949 DollarCaretP
e22ea7cc 950);
d12a4851 951
584420f0 952@RememberOnROptions = qw(DollarCaretP);
d12a4851 953
69893cff
RGS
954=pod
955
956Second, C<optionVars> lists the variables that each option uses to save its
957state.
958
959=cut
960
6b24a4b7
SF
961use vars qw(%optionVars);
962
69893cff 963%optionVars = (
e22ea7cc
RF
964 hashDepth => \$dumpvar::hashDepth,
965 arrayDepth => \$dumpvar::arrayDepth,
966 CommandSet => \$CommandSet,
967 DumpDBFiles => \$dumpvar::dumpDBFiles,
968 DumpPackages => \$dumpvar::dumpPackages,
969 DumpReused => \$dumpvar::dumpReused,
970 HighBit => \$dumpvar::quoteHighBit,
971 undefPrint => \$dumpvar::printUndef,
972 globPrint => \$dumpvar::globPrint,
973 UsageOnly => \$dumpvar::usageOnly,
974 CreateTTY => \$CreateTTY,
975 bareStringify => \$dumpvar::bareStringify,
976 frame => \$frame,
977 AutoTrace => \$trace,
978 inhibit_exit => \$inhibit_exit,
979 maxTraceLen => \$maxtrace,
980 ImmediateStop => \$ImmediateStop,
981 RemotePort => \$remoteport,
982 windowSize => \$window,
5561b870
AK
983 HistFile => \$histfile,
984 HistSize => \$histsize,
69893cff
RGS
985);
986
987=pod
988
989Third, C<%optionAction> defines the subroutine to be called to process each
990option.
991
b570d64b 992=cut
69893cff 993
6b24a4b7
SF
994use vars qw(%optionAction);
995
69893cff
RGS
996%optionAction = (
997 compactDump => \&dumpvar::compactDump,
998 veryCompact => \&dumpvar::veryCompact,
999 quote => \&dumpvar::quote,
1000 TTY => \&TTY,
1001 noTTY => \&noTTY,
1002 ReadLine => \&ReadLine,
1003 NonStop => \&NonStop,
1004 LineInfo => \&LineInfo,
1005 recallCommand => \&recallCommand,
1006 ShellBang => \&shellBang,
1007 pager => \&pager,
1008 signalLevel => \&signalLevel,
1009 warnLevel => \&warnLevel,
1010 dieLevel => \&dieLevel,
1011 tkRunning => \&tkRunning,
1012 ornaments => \&ornaments,
1013 RemotePort => \&RemotePort,
1014 DollarCaretP => \&DollarCaretP,
d12a4851
JH
1015);
1016
69893cff
RGS
1017=pod
1018
1019Last, the C<%optionRequire> notes modules that must be C<require>d if an
1020option is used.
1021
1022=cut
d338d6fe 1023
69893cff
RGS
1024# Note that this list is not complete: several options not listed here
1025# actually require that dumpvar.pl be loaded for them to work, but are
1026# not in the table. A subsequent patch will correct this problem; for
1027# the moment, we're just recommenting, and we are NOT going to change
1028# function.
6b24a4b7
SF
1029use vars qw(%optionRequire);
1030
eda6e075 1031%optionRequire = (
69893cff
RGS
1032 compactDump => 'dumpvar.pl',
1033 veryCompact => 'dumpvar.pl',
1034 quote => 'dumpvar.pl',
e22ea7cc 1035);
69893cff
RGS
1036
1037=pod
1038
1039There are a number of initialization-related variables which can be set
1040by putting code to set them in a BEGIN block in the C<PERL5DB> environment
1041variable. These are:
1042
1043=over 4
1044
1045=item C<$rl> - readline control XXX needs more explanation
1046
1047=item C<$warnLevel> - whether or not debugger takes over warning handling
1048
1049=item C<$dieLevel> - whether or not debugger takes over die handling
1050
1051=item C<$signalLevel> - whether or not debugger takes over signal handling
1052
1053=item C<$pre> - preprompt actions (array reference)
1054
1055=item C<$post> - postprompt actions (array reference)
1056
1057=item C<$pretype>
1058
1059=item C<$CreateTTY> - whether or not to create a new TTY for this debugger
1060
1061=item C<$CommandSet> - which command set to use (defaults to new, documented set)
1062
1063=back
1064
1065=cut
d338d6fe
PP
1066
1067# These guys may be defined in $ENV{PERL5DB} :
69893cff
RGS
1068$rl = 1 unless defined $rl;
1069$warnLevel = 1 unless defined $warnLevel;
1070$dieLevel = 1 unless defined $dieLevel;
1071$signalLevel = 1 unless defined $signalLevel;
1072$pre = [] unless defined $pre;
1073$post = [] unless defined $post;
1074$pretype = [] unless defined $pretype;
1075$CreateTTY = 3 unless defined $CreateTTY;
1076$CommandSet = '580' unless defined $CommandSet;
1077
2cbb2ee1
RGS
1078share($rl);
1079share($warnLevel);
1080share($dieLevel);
1081share($signalLevel);
1082share($pre);
1083share($post);
1084share($pretype);
1085share($rl);
1086share($CreateTTY);
1087share($CommandSet);
1088
69893cff
RGS
1089=pod
1090
1091The default C<die>, C<warn>, and C<signal> handlers are set up.
1092
1093=cut
055fd3a9 1094
d338d6fe
PP
1095warnLevel($warnLevel);
1096dieLevel($dieLevel);
1097signalLevel($signalLevel);
055fd3a9 1098
69893cff
RGS
1099=pod
1100
1101The pager to be used is needed next. We try to get it from the
5561b870 1102environment first. If it's not defined there, we try to find it in
69893cff
RGS
1103the Perl C<Config.pm>. If it's not there, we default to C<more>. We
1104then call the C<pager()> function to save the pager name.
1105
1106=cut
1107
1108# This routine makes sure $pager is set up so that '|' can use it.
4865a36d 1109pager(
e22ea7cc 1110
69893cff 1111 # If PAGER is defined in the environment, use it.
e22ea7cc
RF
1112 defined $ENV{PAGER}
1113 ? $ENV{PAGER}
69893cff
RGS
1114
1115 # If not, see if Config.pm defines it.
e22ea7cc
RF
1116 : eval { require Config }
1117 && defined $Config::Config{pager}
1118 ? $Config::Config{pager}
69893cff
RGS
1119
1120 # If not, fall back to 'more'.
e22ea7cc
RF
1121 : 'more'
1122 )
1123 unless defined $pager;
69893cff
RGS
1124
1125=pod
1126
1127We set up the command to be used to access the man pages, the command
be9a9b1d
AT
1128recall character (C<!> unless otherwise defined) and the shell escape
1129character (C<!> unless otherwise defined). Yes, these do conflict, and
69893cff
RGS
1130neither works in the debugger at the moment.
1131
1132=cut
1133
055fd3a9 1134setman();
69893cff
RGS
1135
1136# Set up defaults for command recall and shell escape (note:
1137# these currently don't work in linemode debugging).
2218c045
SF
1138recallCommand("!") unless defined $prc;
1139shellBang("!") unless defined $psh;
69893cff
RGS
1140
1141=pod
1142
1143We then set up the gigantic string containing the debugger help.
1144We also set the limit on the number of arguments we'll display during a
1145trace.
1146
1147=cut
1148
04e43a21 1149sethelp();
69893cff
RGS
1150
1151# If we didn't get a default for the length of eval/stack trace args,
1152# set it here.
1d06cb2d 1153$maxtrace = 400 unless defined $maxtrace;
69893cff
RGS
1154
1155=head2 SETTING UP THE DEBUGGER GREETING
1156
be9a9b1d 1157The debugger I<greeting> helps to inform the user how many debuggers are
69893cff
RGS
1158running, and whether the current debugger is the primary or a child.
1159
1160If we are the primary, we just hang onto our pid so we'll have it when
1161or if we start a child debugger. If we are a child, we'll set things up
1162so we'll have a unique greeting and so the parent will give us our own
1163TTY later.
1164
1165We save the current contents of the C<PERLDB_PIDS> environment variable
1166because we mess around with it. We'll also need to hang onto it because
1167we'll need it if we restart.
1168
1169Child debuggers make a label out of the current PID structure recorded in
1170PERLDB_PIDS plus the new PID. They also mark themselves as not having a TTY
1171yet so the parent will give them one later via C<resetterm()>.
1172
1173=cut
1174
e22ea7cc 1175# Save the current contents of the environment; we're about to
69893cff 1176# much with it. We'll need this if we have to restart.
6b24a4b7 1177use vars qw($ini_pids);
f1583d8f 1178$ini_pids = $ENV{PERLDB_PIDS};
69893cff 1179
6b24a4b7
SF
1180use vars qw ($pids $term_pid);
1181
e22ea7cc
RF
1182if ( defined $ENV{PERLDB_PIDS} ) {
1183
69893cff 1184 # We're a child. Make us a label out of the current PID structure
e22ea7cc 1185 # recorded in PERLDB_PIDS plus our (new) PID. Mark us as not having
69893cff 1186 # a term yet so the parent will give us one later via resetterm().
55f4245e
JM
1187
1188 my $env_pids = $ENV{PERLDB_PIDS};
1189 $pids = "[$env_pids]";
1190
1191 # Unless we are on OpenVMS, all programs under the DCL shell run under
1192 # the same PID.
1193
1194 if (($^O eq 'VMS') && ($env_pids =~ /\b$$\b/)) {
1195 $term_pid = $$;
1196 }
1197 else {
1198 $ENV{PERLDB_PIDS} .= "->$$";
1199 $term_pid = -1;
1200 }
1201
69893cff
RGS
1202} ## end if (defined $ENV{PERLDB_PIDS...
1203else {
e22ea7cc
RF
1204
1205 # We're the parent PID. Initialize PERLDB_PID in case we end up with a
69893cff
RGS
1206 # child debugger, and mark us as the parent, so we'll know to set up
1207 # more TTY's is we have to.
1208 $ENV{PERLDB_PIDS} = "$$";
619a0444 1209 $pids = "[pid=$$]";
e22ea7cc 1210 $term_pid = $$;
f1583d8f 1211}
69893cff 1212
6b24a4b7 1213use vars qw($pidprompt);
f1583d8f 1214$pidprompt = '';
69893cff
RGS
1215
1216# Sets up $emacs as a synonym for $slave_editor.
7793e5c2 1217our ($slave_editor);
69893cff
RGS
1218*emacs = $slave_editor if $slave_editor; # May be used in afterinit()...
1219
1220=head2 READING THE RC FILE
1221
b570d64b 1222The debugger will read a file of initialization options if supplied. If
69893cff
RGS
1223running interactively, this is C<.perldb>; if not, it's C<perldb.ini>.
1224
b570d64b 1225=cut
69893cff
RGS
1226
1227# As noted, this test really doesn't check accurately that the debugger
1228# is running at a terminal or not.
d338d6fe 1229
6b24a4b7 1230use vars qw($rcfile);
fb4d8a6c
SF
1231{
1232 my $dev_tty = (($^O eq 'VMS') ? 'TT:' : '/dev/tty');
1233 # this is the wrong metric!
1234 $rcfile = ((-e $dev_tty) ? ".perldb" : "perldb.ini");
d338d6fe
PP
1235}
1236
69893cff
RGS
1237=pod
1238
1239The debugger does a safety test of the file to be read. It must be owned
1240either by the current user or root, and must only be writable by the owner.
1241
1242=cut
1243
1244# This wraps a safety test around "do" to read and evaluate the init file.
1245#
055fd3a9
GS
1246# This isn't really safe, because there's a race
1247# between checking and opening. The solution is to
1248# open and fstat the handle, but then you have to read and
1249# eval the contents. But then the silly thing gets
69893cff
RGS
1250# your lexical scope, which is unfortunate at best.
1251sub safe_do {
055fd3a9
GS
1252 my $file = shift;
1253
1254 # Just exactly what part of the word "CORE::" don't you understand?
69893cff
RGS
1255 local $SIG{__WARN__};
1256 local $SIG{__DIE__};
055fd3a9 1257
e22ea7cc 1258 unless ( is_safe_file($file) ) {
69893cff 1259 CORE::warn <<EO_GRIPE;
055fd3a9 1260perldb: Must not source insecure rcfile $file.
b570d64b 1261 You or the superuser must be the owner, and it must not
69893cff 1262 be writable by anyone but its owner.
055fd3a9 1263EO_GRIPE
69893cff
RGS
1264 return;
1265 } ## end unless (is_safe_file($file...
055fd3a9
GS
1266
1267 do $file;
1268 CORE::warn("perldb: couldn't parse $file: $@") if $@;
69893cff 1269} ## end sub safe_do
055fd3a9 1270
69893cff
RGS
1271# This is the safety test itself.
1272#
055fd3a9
GS
1273# Verifies that owner is either real user or superuser and that no
1274# one but owner may write to it. This function is of limited use
1275# when called on a path instead of upon a handle, because there are
1276# no guarantees that filename (by dirent) whose file (by ino) is
e22ea7cc 1277# eventually accessed is the same as the one tested.
055fd3a9
GS
1278# Assumes that the file's existence is not in doubt.
1279sub is_safe_file {
1280 my $path = shift;
69893cff 1281 stat($path) || return; # mysteriously vaporized
e22ea7cc 1282 my ( $dev, $ino, $mode, $nlink, $uid, $gid ) = stat(_);
055fd3a9
GS
1283
1284 return 0 if $uid != 0 && $uid != $<;
1285 return 0 if $mode & 022;
1286 return 1;
69893cff 1287} ## end sub is_safe_file
055fd3a9 1288
69893cff 1289# If the rcfile (whichever one we decided was the right one to read)
e22ea7cc
RF
1290# exists, we safely do it.
1291if ( -f $rcfile ) {
055fd3a9 1292 safe_do("./$rcfile");
69893cff 1293}
e22ea7cc 1294
69893cff 1295# If there isn't one here, try the user's home directory.
e22ea7cc 1296elsif ( defined $ENV{HOME} && -f "$ENV{HOME}/$rcfile" ) {
055fd3a9
GS
1297 safe_do("$ENV{HOME}/$rcfile");
1298}
e22ea7cc 1299
69893cff 1300# Else try the login directory.
e22ea7cc 1301elsif ( defined $ENV{LOGDIR} && -f "$ENV{LOGDIR}/$rcfile" ) {
055fd3a9 1302 safe_do("$ENV{LOGDIR}/$rcfile");
d338d6fe
PP
1303}
1304
69893cff 1305# If the PERLDB_OPTS variable has options in it, parse those out next.
e22ea7cc
RF
1306if ( defined $ENV{PERLDB_OPTS} ) {
1307 parse_options( $ENV{PERLDB_OPTS} );
d338d6fe
PP
1308}
1309
69893cff
RGS
1310=pod
1311
1312The last thing we do during initialization is determine which subroutine is
1313to be used to obtain a new terminal when a new debugger is started. Right now,
b0b54b5e 1314the debugger only handles TCP sockets, X11, OS/2, amd Mac OS X
11653f7f 1315(darwin).
69893cff
RGS
1316
1317=cut
1318
1319# Set up the get_fork_TTY subroutine to be aliased to the proper routine.
1320# Works if you're running an xterm or xterm-like window, or you're on
6fae1ad7
RF
1321# OS/2, or on Mac OS X. This may need some expansion.
1322
1323if (not defined &get_fork_TTY) # only if no routine exists
69893cff 1324{
b570d64b 1325 if ( defined $remoteport ) {
11653f7f
JJ
1326 # Expect an inetd-like server
1327 *get_fork_TTY = \&socket_get_fork_TTY; # to listen to us
1328 }
1329 elsif (defined $ENV{TERM} # If we know what kind
6fae1ad7
RF
1330 # of terminal this is,
1331 and $ENV{TERM} eq 'xterm' # and it's an xterm,
1332 and defined $ENV{DISPLAY} # and what display it's on,
1333 )
1334 {
1335 *get_fork_TTY = \&xterm_get_fork_TTY; # use the xterm version
1336 }
1337 elsif ( $^O eq 'os2' ) { # If this is OS/2,
1338 *get_fork_TTY = \&os2_get_fork_TTY; # use the OS/2 version
1339 }
1340 elsif ( $^O eq 'darwin' # If this is Mac OS X
1341 and defined $ENV{TERM_PROGRAM} # and we're running inside
1342 and $ENV{TERM_PROGRAM}
1343 eq 'Apple_Terminal' # Terminal.app
1344 )
1345 {
1346 *get_fork_TTY = \&macosx_get_fork_TTY; # use the Mac OS X version
1347 }
69893cff 1348} ## end if (not defined &get_fork_TTY...
e22ea7cc 1349
dbb46cec
DQ
1350# untaint $^O, which may have been tainted by the last statement.
1351# see bug [perl #24674]
e22ea7cc
RF
1352$^O =~ m/^(.*)\z/;
1353$^O = $1;
f1583d8f 1354
d12a4851 1355# Here begin the unreadable code. It needs fixing.
055fd3a9 1356
69893cff
RGS
1357=head2 RESTART PROCESSING
1358
1359This section handles the restart command. When the C<R> command is invoked, it
1360tries to capture all of the state it can into environment variables, and
1361then sets C<PERLDB_RESTART>. When we start executing again, we check to see
1362if C<PERLDB_RESTART> is there; if so, we reload all the information that
1363the R command stuffed into the environment variables.
1364
b570d64b 1365 PERLDB_RESTART - flag only, contains no restart data itself.
69893cff
RGS
1366 PERLDB_HIST - command history, if it's available
1367 PERLDB_ON_LOAD - breakpoints set by the rc file
1368 PERLDB_POSTPONE - subs that have been loaded/not executed, and have actions
1369 PERLDB_VISITED - files that had breakpoints
1370 PERLDB_FILE_... - breakpoints for a file
1371 PERLDB_OPT - active options
1372 PERLDB_INC - the original @INC
1373 PERLDB_PRETYPE - preprompt debugger actions
1374 PERLDB_PRE - preprompt Perl code
1375 PERLDB_POST - post-prompt Perl code
1376 PERLDB_TYPEAHEAD - typeahead captured by readline()
1377
1378We chug through all these variables and plug the values saved in them
1379back into the appropriate spots in the debugger.
1380
1381=cut
1382
14f38b27
SF
1383use vars qw(@truehist %postponed_file @typeahead);
1384
1385our (@hist);
6b24a4b7 1386
fb0fb5f4
SF
1387sub _restore_shared_globals_after_restart
1388{
1389 @hist = get_list('PERLDB_HIST');
1390 %break_on_load = get_list("PERLDB_ON_LOAD");
1391 %postponed = get_list("PERLDB_POSTPONE");
1392
1393 share(@hist);
1394 share(@truehist);
1395 share(%break_on_load);
1396 share(%postponed);
1397}
1398
e18a02a6 1399sub _restore_breakpoints_and_actions {
e22ea7cc 1400
e22ea7cc 1401 my @had_breakpoints = get_list("PERLDB_VISITED");
e18a02a6 1402
bdba49ad
SF
1403 for my $file_idx ( 0 .. $#had_breakpoints ) {
1404 my $filename = $had_breakpoints[$file_idx];
1405 my %pf = get_list("PERLDB_FILE_$file_idx");
1406 $postponed_file{ $filename } = \%pf if %pf;
1407 my @lines = sort {$a <=> $b} keys(%pf);
1408 my @enabled_statuses = get_list("PERLDB_FILE_ENABLED_$file_idx");
1409 for my $line_idx (0 .. $#lines) {
1410 _set_breakpoint_enabled_status(
1411 $filename,
1412 $lines[$line_idx],
1413 ($enabled_statuses[$line_idx] ? 1 : ''),
1414 );
1415 }
e22ea7cc 1416 }
69893cff 1417
e18a02a6
SF
1418 return;
1419}
1420
ca50076b
SF
1421sub _restore_options_after_restart
1422{
1423 my %options_map = get_list("PERLDB_OPT");
1424
1425 while ( my ( $opt, $val ) = each %options_map ) {
1426 $val =~ s/[\\\']/\\$1/g;
1427 parse_options("$opt'$val'");
1428 }
1429
1430 return;
1431}
1432
18580168
SF
1433sub _restore_globals_after_restart
1434{
1435 # restore original @INC
1436 @INC = get_list("PERLDB_INC");
1437 @ini_INC = @INC;
1438
1439 # return pre/postprompt actions and typeahead buffer
1440 $pretype = [ get_list("PERLDB_PRETYPE") ];
1441 $pre = [ get_list("PERLDB_PRE") ];
1442 $post = [ get_list("PERLDB_POST") ];
1443 @typeahead = get_list( "PERLDB_TYPEAHEAD", @typeahead );
1444
1445 return;
1446}
1447
fb0fb5f4 1448
e18a02a6
SF
1449if ( exists $ENV{PERLDB_RESTART} ) {
1450
1451 # We're restarting, so we don't need the flag that says to restart anymore.
1452 delete $ENV{PERLDB_RESTART};
1453
1454 # $restart = 1;
fb0fb5f4 1455 _restore_shared_globals_after_restart();
e18a02a6
SF
1456
1457 _restore_breakpoints_and_actions();
1458
69893cff 1459 # restore options
ca50076b 1460 _restore_options_after_restart();
69893cff 1461
18580168 1462 _restore_globals_after_restart();
69893cff
RGS
1463} ## end if (exists $ENV{PERLDB_RESTART...
1464
1465=head2 SETTING UP THE TERMINAL
1466
1467Now, we'll decide how the debugger is going to interact with the user.
1468If there's no TTY, we set the debugger to run non-stop; there's not going
1469to be anyone there to enter commands.
1470
1471=cut
54d04a52 1472
ebd0282e 1473use vars qw($notty $console $tty $LINEINFO);
6b24a4b7
SF
1474use vars qw($lineinfo $doccmd);
1475
ebd0282e
SF
1476our ($runnonstop);
1477
d338d6fe 1478if ($notty) {
69893cff 1479 $runnonstop = 1;
2dbd01ad 1480 share($runnonstop);
69893cff 1481}
d12a4851 1482
69893cff
RGS
1483=pod
1484
1485If there is a TTY, we have to determine who it belongs to before we can
1486proceed. If this is a slave editor or graphical debugger (denoted by
1487the first command-line switch being '-emacs'), we shift this off and
1488set C<$rl> to 0 (XXX ostensibly to do straight reads).
1489
1490=cut
1491
1492else {
e22ea7cc 1493
69893cff
RGS
1494 # Is Perl being run from a slave editor or graphical debugger?
1495 # If so, don't use readline, and set $slave_editor = 1.
2b0b9dd1
SF
1496 if ($slave_editor = ( @main::ARGV && ( $main::ARGV[0] eq '-emacs' ) )) {
1497 $rl = 0;
1498 shift(@main::ARGV);
1499 }
e22ea7cc
RF
1500
1501 #require Term::ReadLine;
d12a4851 1502
69893cff
RGS
1503=pod
1504
1505We then determine what the console should be on various systems:
1506
1507=over 4
1508
1509=item * Cygwin - We use C<stdin> instead of a separate device.
1510
1511=cut
1512
e22ea7cc
RF
1513 if ( $^O eq 'cygwin' ) {
1514
69893cff
RGS
1515 # /dev/tty is binary. use stdin for textmode
1516 undef $console;
1517 }
1518
1519=item * Unix - use C</dev/tty>.
1520
1521=cut
1522
e22ea7cc 1523 elsif ( -e "/dev/tty" ) {
69893cff
RGS
1524 $console = "/dev/tty";
1525 }
1526
1527=item * Windows or MSDOS - use C<con>.
1528
1529=cut
1530
e22ea7cc 1531 elsif ( $^O eq 'dos' or -e "con" or $^O eq 'MSWin32' ) {
69893cff
RGS
1532 $console = "con";
1533 }
1534
69893cff
RGS
1535=item * VMS - use C<sys$command>.
1536
1537=cut
1538
1539 else {
e22ea7cc 1540
69893cff
RGS
1541 # everything else is ...
1542 $console = "sys\$command";
d12a4851 1543 }
69893cff
RGS
1544
1545=pod
1546
1547=back
1548
1549Several other systems don't use a specific console. We C<undef $console>
1550for those (Windows using a slave editor/graphical debugger, NetWare, OS/2
1551with a slave editor, Epoc).
1552
1553=cut
d12a4851 1554
e22ea7cc
RF
1555 if ( ( $^O eq 'MSWin32' ) and ( $slave_editor or defined $ENV{EMACS} ) ) {
1556
69893cff 1557 # /dev/tty is binary. use stdin for textmode
e22ea7cc
RF
1558 $console = undef;
1559 }
1560
1561 if ( $^O eq 'NetWare' ) {
d12a4851 1562
69893cff
RGS
1563 # /dev/tty is binary. use stdin for textmode
1564 $console = undef;
1565 }
d12a4851 1566
69893cff
RGS
1567 # In OS/2, we need to use STDIN to get textmode too, even though
1568 # it pretty much looks like Unix otherwise.
e22ea7cc
RF
1569 if ( defined $ENV{OS2_SHELL} and ( $slave_editor or $ENV{WINDOWID} ) )
1570 { # In OS/2
1571 $console = undef;
1572 }
1573
1574 # EPOC also falls into the 'got to use STDIN' camp.
1575 if ( $^O eq 'epoc' ) {
1576 $console = undef;
1577 }
d12a4851 1578
69893cff
RGS
1579=pod
1580
1581If there is a TTY hanging around from a parent, we use that as the console.
1582
1583=cut
1584
e22ea7cc 1585 $console = $tty if defined $tty;
d12a4851 1586
b570d64b 1587=head2 SOCKET HANDLING
69893cff
RGS
1588
1589The debugger is capable of opening a socket and carrying out a debugging
1590session over the socket.
1591
1592If C<RemotePort> was defined in the options, the debugger assumes that it
1593should try to start a debugging session on that port. It builds the socket
1594and then tries to connect the input and output filehandles to it.
1595
1596=cut
1597
1598 # Handle socket stuff.
e22ea7cc
RF
1599
1600 if ( defined $remoteport ) {
1601
69893cff
RGS
1602 # If RemotePort was defined in the options, connect input and output
1603 # to the socket.
11653f7f 1604 $IN = $OUT = connect_remoteport();
69893cff
RGS
1605 } ## end if (defined $remoteport)
1606
1607=pod
1608
1609If no C<RemotePort> was defined, and we want to create a TTY on startup,
1610this is probably a situation where multiple debuggers are running (for example,
1611a backticked command that starts up another debugger). We create a new IN and
1612OUT filehandle, and do the necessary mojo to create a new TTY if we know how
1613and if we can.
1614
1615=cut
1616
1617 # Non-socket.
1618 else {
e22ea7cc 1619
69893cff
RGS
1620 # Two debuggers running (probably a system or a backtick that invokes
1621 # the debugger itself under the running one). create a new IN and OUT
e22ea7cc 1622 # filehandle, and do the necessary mojo to create a new tty if we
69893cff 1623 # know how, and we can.
e22ea7cc
RF
1624 create_IN_OUT(4) if $CreateTTY & 4;
1625 if ($console) {
1626
69893cff 1627 # If we have a console, check to see if there are separate ins and
cd1191f1 1628 # outs to open. (They are assumed identical if not.)
69893cff 1629
e22ea7cc
RF
1630 my ( $i, $o ) = split /,/, $console;
1631 $o = $i unless defined $o;
69893cff 1632
69893cff 1633 # read/write on in, or just read, or read on STDIN.
e22ea7cc
RF
1634 open( IN, "+<$i" )
1635 || open( IN, "<$i" )
1636 || open( IN, "<&STDIN" );
1637
69893cff
RGS
1638 # read/write/create/clobber out, or write/create/clobber out,
1639 # or merge with STDERR, or merge with STDOUT.
e22ea7cc
RF
1640 open( OUT, "+>$o" )
1641 || open( OUT, ">$o" )
1642 || open( OUT, ">&STDERR" )
1643 || open( OUT, ">&STDOUT" ); # so we don't dongle stdout
1644
1645 } ## end if ($console)
1646 elsif ( not defined $console ) {
1647
1648 # No console. Open STDIN.
1649 open( IN, "<&STDIN" );
1650
1651 # merge with STDERR, or with STDOUT.
1652 open( OUT, ">&STDERR" )
1653 || open( OUT, ">&STDOUT" ); # so we don't dongle stdout
1654 $console = 'STDIN/OUT';
69893cff
RGS
1655 } ## end elsif (not defined $console)
1656
1657 # Keep copies of the filehandles so that when the pager runs, it
1658 # can close standard input without clobbering ours.
2b0b9dd1
SF
1659 if ($console or (not defined($console))) {
1660 $IN = \*IN;
1661 $OUT = \*OUT;
1662 }
e22ea7cc
RF
1663 } ## end elsif (from if(defined $remoteport))
1664
1665 # Unbuffer DB::OUT. We need to see responses right away.
70c9432b 1666 $OUT->autoflush(1);
e22ea7cc
RF
1667
1668 # Line info goes to debugger output unless pointed elsewhere.
1669 # Pointing elsewhere makes it possible for slave editors to
1670 # keep track of file and position. We have both a filehandle
1671 # and a I/O description to keep track of.
1672 $LINEINFO = $OUT unless defined $LINEINFO;
1673 $lineinfo = $console unless defined $lineinfo;
2dbd01ad
SF
1674 # share($LINEINFO); # <- unable to share globs
1675 share($lineinfo); #
e22ea7cc 1676
69893cff
RGS
1677=pod
1678
1679To finish initialization, we show the debugger greeting,
1680and then call the C<afterinit()> subroutine if there is one.
1681
1682=cut
d12a4851 1683
e22ea7cc
RF
1684 # Show the debugger greeting.
1685 $header =~ s/.Header: ([^,]+),v(\s+\S+\s+\S+).*$/$1$2/;
1686 unless ($runnonstop) {
1687 local $\ = '';
1688 local $, = '';
1689 if ( $term_pid eq '-1' ) {
1690 print $OUT "\nDaughter DB session started...\n";
1691 }
1692 else {
1693 print $OUT "\nLoading DB routines from $header\n";
1694 print $OUT (
1695 "Editor support ",
1696 $slave_editor ? "enabled" : "available", ".\n"
1697 );
1698 print $OUT
1f874cb6 1699"\nEnter h or 'h h' for help, or '$doccmd perldebug' for more help.\n\n";
69893cff
RGS
1700 } ## end else [ if ($term_pid eq '-1')
1701 } ## end unless ($runnonstop)
1702} ## end else [ if ($notty)
1703
1704# XXX This looks like a bug to me.
1705# Why copy to @ARGS and then futz with @args?
d338d6fe 1706@ARGS = @ARGV;
6b24a4b7 1707# for (@args) {
69893cff
RGS
1708 # Make sure backslashes before single quotes are stripped out, and
1709 # keep args unless they are numeric (XXX why?)
e22ea7cc
RF
1710 # s/\'/\\\'/g; # removed while not justified understandably
1711 # s/(.*)/'$1'/ unless /^-?[\d.]+$/; # ditto
6b24a4b7 1712# }
d338d6fe 1713
e22ea7cc 1714# If there was an afterinit() sub defined, call it. It will get
69893cff 1715# executed in our scope, so it can fiddle with debugger globals.
e22ea7cc 1716if ( defined &afterinit ) { # May be defined in $rcfile
2b0b9dd1 1717 afterinit();
d338d6fe 1718}
e22ea7cc 1719
69893cff 1720# Inform us about "Stack dump during die enabled ..." in dieLevel().
6b24a4b7
SF
1721use vars qw($I_m_init);
1722
43aed9ee
IZ
1723$I_m_init = 1;
1724
d338d6fe
PP
1725############################################################ Subroutines
1726
69893cff
RGS
1727=head1 SUBROUTINES
1728
1729=head2 DB
1730
1731This gigantic subroutine is the heart of the debugger. Called before every
1732statement, its job is to determine if a breakpoint has been reached, and
1733stop if so; read commands from the user, parse them, and execute
b468dcb6 1734them, and then send execution off to the next statement.
69893cff
RGS
1735
1736Note that the order in which the commands are processed is very important;
1737some commands earlier in the loop will actually alter the C<$cmd> variable
be9a9b1d 1738to create other commands to be executed later. This is all highly I<optimized>
69893cff
RGS
1739but can be confusing. Check the comments for each C<$cmd ... && do {}> to
1740see what's happening in any given command.
1741
1742=cut
1743
136ae23d
SF
1744# $cmd cannot be an our() variable unfortunately (possible perl bug?).
1745
6b24a4b7
SF
1746use vars qw(
1747 $action
1748 %alias
1749 $cmd
6b24a4b7
SF
1750 $fall_off_end
1751 $file
1752 $filename_ini
1753 $finished
1754 %had_breakpoints
6b24a4b7
SF
1755 $level
1756 $max
6b24a4b7 1757 $package
6b24a4b7 1758 $sh
6b24a4b7 1759 $try
2c247e84 1760 $end
6b24a4b7
SF
1761);
1762
1ce985d2
SF
1763our (
1764 $doret,
d1450c23 1765 $incr,
73c5e526 1766 $laststep,
14f38b27 1767 $rc,
1ce985d2
SF
1768 $stack_depth,
1769 @stack,
1770 @to_watch,
1771 @old_watch,
1772);
8ad70697 1773
6791e41b
SF
1774sub _DB__determine_if_we_should_break
1775{
1776 # if we have something here, see if we should break.
1777 # $stop is lexical and local to this block - $action on the other hand
1778 # is global.
1779 my $stop;
1780
1781 if ( $dbline{$line}
1782 && _is_breakpoint_enabled($filename, $line)
1783 && (( $stop, $action ) = split( /\0/, $dbline{$line} ) ) )
1784 {
1785
1786 # Stop if the stop criterion says to just stop.
1787 if ( $stop eq '1' ) {
1788 $signal |= 1;
1789 }
1790
1791 # It's a conditional stop; eval it in the user's context and
1792 # see if we should stop. If so, remove the one-time sigil.
1793 elsif ($stop) {
1794 $evalarg = "\$DB::signal |= 1 if do {$stop}";
6cff0f90 1795 DB::eval();
6791e41b
SF
1796 # If the breakpoint is temporary, then delete its enabled status.
1797 if ($dbline{$line} =~ s/;9($|\0)/$1/) {
1798 _cancel_breakpoint_temp_enabled_status($filename, $line);
1799 }
1800 }
1801 } ## end if ($dbline{$line} && ...
1802}
1803
8481f647
SF
1804sub _DB__is_finished {
1805 if ($finished and $level <= 1) {
1806 end_report();
1807 return 1;
1808 }
1809 else {
1810 return;
1811 }
1812}
1813
32bbadc6
SF
1814sub _DB__read_next_cmd
1815{
1816 my ($tid) = @_;
1817
1818 # We have a terminal, or can get one ...
1819 if (!$term) {
1820 setterm();
1821 }
1822
1823 # ... and it belogs to this PID or we get one for this PID ...
1824 if ($term_pid != $$) {
1825 resetterm(1);
1826 }
1827
1828 # ... and we got a line of command input ...
1829 $cmd = DB::readline(
1830 "$pidprompt $tid DB"
1831 . ( '<' x $level )
1832 . ( $#hist + 1 )
1833 . ( '>' x $level ) . " "
1834 );
1835
1836 return defined($cmd);
1837}
1838
7013f40c
SF
1839sub _DB__trim_command_and_return_first_component {
1840 $cmd =~ s/\A\s+//s; # trim annoying leading whitespace
1841 $cmd =~ s/\s+\z//s; # trim annoying trailing whitespace
1842
1843 $cmd =~ m{\A(\S*)};
1844 return $1;
1845}
1846
2a802473
SF
1847sub _DB__handle_f_command {
1848 if (($file) = $cmd =~ /\Af\b\s*(.*)/) {
1849 $file =~ s/\s+$//;
1850
1851 # help for no arguments (old-style was return from sub).
1852 if ( !$file ) {
1853 print $OUT
1854 "The old f command is now the r command.\n"; # hint
1855 print $OUT "The new f command switches filenames.\n";
1856 next CMD;
1857 } ## end if (!$file)
1858
1859 # if not in magic file list, try a close match.
1860 if ( !defined $main::{ '_<' . $file } ) {
1861 if ( ($try) = grep( m#^_<.*$file#, keys %main:: ) ) {
1862 {
1863 $try = substr( $try, 2 );
1864 print $OUT "Choosing $try matching '$file':\n";
1865 $file = $try;
1866 }
1867 } ## end if (($try) = grep(m#^_<.*$file#...
1868 } ## end if (!defined $main::{ ...
1869
1870 # If not successfully switched now, we failed.
1871 if ( !defined $main::{ '_<' . $file } ) {
1872 print $OUT "No file matching '$file' is loaded.\n";
1873 next CMD;
1874 }
1875
1876 # We switched, so switch the debugger internals around.
1877 elsif ( $file ne $filename ) {
1878 *dbline = $main::{ '_<' . $file };
1879 $max = $#dbline;
1880 $filename = $file;
1881 $start = 1;
1882 $cmd = "l";
1883 } ## end elsif ($file ne $filename)
1884
1885 # We didn't switch; say we didn't.
1886 else {
1887 print $OUT "Already in $file.\n";
1888 next CMD;
1889 }
1890 }
1891
1892 return;
1893}
1894
6115a173
SF
1895sub _DB__handle_dot_command {
1896 my ($obj) = @_;
1897
1898 # . command.
1899 if ($cmd eq '.') {
1900 $incr = -1; # stay at current line
1901
1902 # Reset everything to the old location.
1903 $start = $line;
1904 $filename = $filename_ini;
1905 *dbline = $main::{ '_<' . $filename };
1906 $max = $#dbline;
1907
1908 # Now where are we?
1909 print_lineinfo($obj->position());
1910 next CMD;
1911 }
1912
1913 return;
1914}
1915
5c2b78e7
SF
1916sub _DB__handle_y_command {
1917 my ($obj) = @_;
1918
1919 if (my ($match_level, $match_vars)
1920 = $cmd =~ /^y(?:\s+(\d*)\s*(.*))?$/) {
1921
1922 # See if we've got the necessary support.
84e7f475
SF
1923 if (!eval { require PadWalker; PadWalker->VERSION(0.08) }) {
1924 my $Err = $@;
1925 DB::warn(
1926 $Err =~ /locate/
1927 ? "PadWalker module not found - please install\n"
1928 : $Err
1929 );
1930 next CMD;
1931 }
5c2b78e7
SF
1932
1933 # Load up dumpvar if we don't have it. If we can, that is.
1934 do 'dumpvar.pl' || die $@ unless defined &main::dumpvar;
1935 defined &main::dumpvar
1936 or print $OUT "dumpvar.pl not available.\n"
1937 and next CMD;
1938
1939 # Got all the modules we need. Find them and print them.
1940 my @vars = split( ' ', $match_vars || '' );
1941
1942 # Find the pad.
1943 my $h = eval { PadWalker::peek_my( ( $match_level || 0 ) + 1 ) };
1944
1945 # Oops. Can't find it.
84e7f475
SF
1946 if (my $Err = $@) {
1947 $Err =~ s/ at .*//;
1948 DB::warn($Err);
1949 next CMD;
1950 }
5c2b78e7
SF
1951
1952 # Show the desired vars with dumplex().
1953 my $savout = select($OUT);
1954
1955 # Have dumplex dump the lexicals.
84e7f475
SF
1956 foreach my $key (sort keys %$h) {
1957 dumpvar::dumplex( $key, $h->{$key},
1958 defined $option{dumpDepth} ? $option{dumpDepth} : -1,
1959 @vars );
1960 }
5c2b78e7
SF
1961 select($savout);
1962 next CMD;
1963 }
1964}
1965
35cd713a
SF
1966sub _DB__handle_c_command {
1967 my ($obj) = @_;
1968
1969 if (my ($new_i) = $cmd =~ m#\Ac\b\s*([\w:]*)\s*\z#) {
1970
1971 $obj->i_cmd($new_i);
1972
1973 # Hey, show's over. The debugged program finished
1974 # executing already.
1975 next CMD if _DB__is_finished();
1976
1977 # Capture the place to put a one-time break.
1978 $subname = $obj->i_cmd;
1979
1980 # Probably not needed, since we finish an interactive
1981 # sub-session anyway...
1982 # local $filename = $filename;
1983 # local *dbline = *dbline; # XXX Would this work?!
1984 #
1985 # The above question wonders if localizing the alias
1986 # to the magic array works or not. Since it's commented
1987 # out, we'll just leave that to speculation for now.
1988
1989 # If the "subname" isn't all digits, we'll assume it
1990 # is a subroutine name, and try to find it.
1991 if ( $subname =~ /\D/ ) { # subroutine name
1992 # Qualify it to the current package unless it's
1993 # already qualified.
1994 $subname = $package . "::" . $subname
1995 unless $subname =~ /::/;
1996
1997 # find_sub will return "file:line_number" corresponding
1998 # to where the subroutine is defined; we call find_sub,
1999 # break up the return value, and assign it in one
2000 # operation.
2001 ( $file, $new_i ) = ( find_sub($subname) =~ /^(.*):(.*)$/ );
2002
2003 # Force the line number to be numeric.
2004 $obj->i_cmd($new_i + 0);
2005
2006 # If we got a line number, we found the sub.
2007 if ($obj->i_cmd) {
2008
2009 # Switch all the debugger's internals around so
2010 # we're actually working with that file.
2011 $filename = $file;
2012 *dbline = $main::{ '_<' . $filename };
2013
2014 # Mark that there's a breakpoint in this file.
2015 $had_breakpoints{$filename} |= 1;
2016
2017 # Scan forward to the first executable line
2018 # after the 'sub whatever' line.
2019 $max = $#dbline;
2020 my $ii = $obj->i_cmd;
2021 ++$ii while $dbline[$ii] == 0 && $ii < $max;
2022 $obj->i_cmd($ii);
2023 } ## end if ($i)
2024
2025 # We didn't find a sub by that name.
2026 else {
2027 print $OUT "Subroutine $subname not found.\n";
2028 next CMD;
2029 }
2030 } ## end if ($subname =~ /\D/)
2031
2032 # At this point, either the subname was all digits (an
2033 # absolute line-break request) or we've scanned through
2034 # the code following the definition of the sub, looking
2035 # for an executable, which we may or may not have found.
2036 #
2037 # If $i (which we set $subname from) is non-zero, we
2038 # got a request to break at some line somewhere. On
2039 # one hand, if there wasn't any real subroutine name
2040 # involved, this will be a request to break in the current
2041 # file at the specified line, so we have to check to make
2042 # sure that the line specified really is breakable.
2043 #
2044 # On the other hand, if there was a subname supplied, the
2045 # preceding block has moved us to the proper file and
2046 # location within that file, and then scanned forward
2047 # looking for the next executable line. We have to make
2048 # sure that one was found.
2049 #
2050 # On the gripping hand, we can't do anything unless the
2051 # current value of $i points to a valid breakable line.
2052 # Check that.
2053 if ($obj->i_cmd) {
2054
2055 # Breakable?
2056 if ( $dbline[$obj->i_cmd] == 0 ) {
2057 print $OUT "Line " . $obj->i_cmd . " not breakable.\n";
2058 next CMD;
2059 }
2060
2061 # Yes. Set up the one-time-break sigil.
2062 $dbline{$obj->i_cmd} =~ s/($|\0)/;9$1/; # add one-time-only b.p.
2063 _enable_breakpoint_temp_enabled_status($filename, $obj->i_cmd);
2064 } ## end if ($i)
2065
2066 # Turn off stack tracing from here up.
2067 for my $i (0 .. $stack_depth) {
2068 $stack[ $i ] &= ~1;
2069 }
2070 last CMD;
2071 }
2072
2073 return;
2074}
2075
a4d311a3
SF
2076sub _DB__handle_forward_slash_command {
2077 my ($obj) = @_;
2078
2079 # The pattern as a string.
2080 use vars qw($inpat);
2081
2082 if (($inpat) = $cmd =~ m#\A/(.*)\z#) {
2083
2084 # Remove the final slash.
2085 $inpat =~ s:([^\\])/$:$1:;
2086
2087 # If the pattern isn't null ...
2088 if ( $inpat ne "" ) {
2089
2090 # Turn of warn and die procesing for a bit.
2091 local $SIG{__DIE__};
2092 local $SIG{__WARN__};
2093
2094 # Create the pattern.
2095 eval 'no strict q/vars/; $inpat =~ m' . "\a$inpat\a";
2096 if ( $@ ne "" ) {
2097
2098 # Oops. Bad pattern. No biscuit.
2099 # Print the eval error and go back for more
2100 # commands.
2101 print $OUT "$@";
2102 next CMD;
2103 }
2104 $obj->pat($inpat);
2105 } ## end if ($inpat ne "")
2106
2107 # Set up to stop on wrap-around.
2108 $end = $start;
2109
2110 # Don't move off the current line.
2111 $incr = -1;
2112
2113 my $pat = $obj->pat;
2114
2115 # Done in eval so nothing breaks if the pattern
2116 # does something weird.
2117 eval
2118 {
2119 no strict q/vars/;
2120 for (;;) {
2121 # Move ahead one line.
2122 ++$start;
2123
2124 # Wrap if we pass the last line.
2125 $start = 1 if ($start > $max);
2126
2127 # Stop if we have gotten back to this line again,
2128 last if ($start == $end);
2129
2130 # A hit! (Note, though, that we are doing
2131 # case-insensitive matching. Maybe a qr//
2132 # expression would be better, so the user could
2133 # do case-sensitive matching if desired.
2134 if ($dbline[$start] =~ m/$pat/i) {
2135 if ($slave_editor) {
2136 # Handle proper escaping in the slave.
2137 print $OUT "\032\032$filename:$start:0\n";
2138 }
2139 else {
2140 # Just print the line normally.
2141 print $OUT "$start:\t",$dbline[$start],"\n";
2142 }
2143 # And quit since we found something.
2144 last;
2145 }
2146 }
2147 };
2148
2149 if ($@) {
2150 warn $@;
2151 }
2152
2153 # If we wrapped, there never was a match.
2154 if ( $start == $end ) {
2155 print {$OUT} "/$pat/: not found\n";
2156 }
2157 next CMD;
2158 }
2159
2160 return;
2161}
2162
11f0f050
SF
2163sub _DB__handle_question_mark_command {
2164 my ($obj) = @_;
2165
2166 # ? - backward pattern search.
2167 if (my ($inpat) = $cmd =~ m#\A\?(.*)\z#) {
2168
2169 # Get the pattern, remove trailing question mark.
2170 $inpat =~ s:([^\\])\?$:$1:;
2171
2172 # If we've got one ...
2173 if ( $inpat ne "" ) {
2174
2175 # Turn off die & warn handlers.
2176 local $SIG{__DIE__};
2177 local $SIG{__WARN__};
2178 eval '$inpat =~ m' . "\a$inpat\a";
2179
2180 if ( $@ ne "" ) {
2181
2182 # Ouch. Not good. Print the error.
2183 print $OUT $@;
2184 next CMD;
2185 }
2186 $obj->pat($inpat);
2187 } ## end if ($inpat ne "")
2188
2189 # Where we are now is where to stop after wraparound.
2190 $end = $start;
2191
2192 # Don't move away from this line.
2193 $incr = -1;
2194
2195 my $pat = $obj->pat;
2196 # Search inside the eval to prevent pattern badness
2197 # from killing us.
2198 eval {
2199 no strict q/vars/;
2200 for (;;) {
2201 # Back up a line.
2202 --$start;
2203
2204 # Wrap if we pass the first line.
2205
2206 $start = $max if ($start <= 0);
2207
2208 # Quit if we get back where we started,
2209 last if ($start == $end);
2210
2211 # Match?
2212 if ($dbline[$start] =~ m/$pat/i) {
2213 if ($slave_editor) {
2214 # Yep, follow slave editor requirements.
2215 print $OUT "\032\032$filename:$start:0\n";
2216 }
2217 else {
2218 # Yep, just print normally.
2219 print $OUT "$start:\t",$dbline[$start],"\n";
2220 }
2221
2222 # Found, so done.
2223 last;
2224 }
2225 }
2226 };
2227
2228 # Say we failed if the loop never found anything,
2229 if ( $start == $end ) {
2230 print {$OUT} "?$pat?: not found\n";
2231 }
2232 next CMD;
2233 }
2234
2235 return;
2236}
2237
2b0b9dd1
SF
2238sub DB {
2239
2240 # lock the debugger and get the thread id for the prompt
2241 lock($DBGR);
2242 my $tid;
2243 my $position;
2244 my ($prefix, $after, $infix);
2245 my $pat;
22fc883d 2246 my $explicit_stop;
2b0b9dd1
SF
2247
2248 if ($ENV{PERL5DB_THREADED}) {
2249 $tid = eval { "[".threads->tid."]" };
2250 }
2251
35cd713a
SF
2252 my $i;
2253
22fc883d
SF
2254 my $obj = DB::Obj->new(
2255 {
2256 position => \$position,
2257 prefix => \$prefix,
2258 after => \$after,
2259 explicit_stop => \$explicit_stop,
2260 infix => \$infix,
35cd713a 2261 i_cmd => \$i,
a4d311a3 2262 pat => \$pat,
22fc883d
SF
2263 },
2264 );
2265
2266 $obj->_DB_on_init__initialize_globals(@_);
2b0b9dd1 2267
69893cff
RGS
2268 # Preserve current values of $@, $!, $^E, $,, $/, $\, $^W.
2269 # The code being debugged may have altered them.
d338d6fe 2270 &save;
69893cff
RGS
2271
2272 # Since DB::DB gets called after every line, we can use caller() to
2273 # figure out where we last were executing. Sneaky, eh? This works because
e22ea7cc 2274 # caller is returning all the extra information when called from the
69893cff 2275 # debugger.
e22ea7cc 2276 local ( $package, $filename, $line ) = caller;
6b24a4b7 2277 $filename_ini = $filename;
69893cff
RGS
2278
2279 # set up the context for DB::eval, so it can properly execute
2280 # code on behalf of the user. We add the package in so that the
2281 # code is eval'ed in the proper package (not in the debugger!).
6b24a4b7 2282 local $usercontext = _calc_usercontext($package);
69893cff
RGS
2283
2284 # Create an alias to the active file magical array to simplify
2285 # the code here.
e22ea7cc 2286 local (*dbline) = $main::{ '_<' . $filename };
aa057b67 2287
69893cff 2288 # Last line in the program.
55783941 2289 $max = $#dbline;
69893cff 2290
22fc883d 2291 _DB__determine_if_we_should_break(@_);
69893cff
RGS
2292
2293 # Preserve the current stop-or-not, and see if any of the W
2294 # (watch expressions) has changed.
36477c24 2295 my $was_signal = $signal;
69893cff
RGS
2296
2297 # If we have any watch expressions ...
22fc883d 2298 $obj->_DB__handle_watch_expressions(@_);
69893cff
RGS
2299
2300=head2 C<watchfunction()>
2301
2302C<watchfunction()> is a function that can be defined by the user; it is a
b570d64b 2303function which will be run on each entry to C<DB::DB>; it gets the
69893cff
RGS
2304current package, filename, and line as its parameters.
2305
b570d64b 2306The watchfunction can do anything it likes; it is executing in the
69893cff
RGS
2307debugger's context, so it has access to all of the debugger's internal
2308data structures and functions.
2309
2310C<watchfunction()> can control the debugger's actions. Any of the following
2311will cause the debugger to return control to the user's program after
2312C<watchfunction()> executes:
2313
b570d64b 2314=over 4
69893cff 2315
be9a9b1d
AT
2316=item *
2317
2318Returning a false value from the C<watchfunction()> itself.
2319
2320=item *
2321
2322Altering C<$single> to a false value.
2323
2324=item *
69893cff 2325
be9a9b1d 2326Altering C<$signal> to a false value.
69893cff 2327
be9a9b1d 2328=item *
69893cff 2329
be9a9b1d 2330Turning off the C<4> bit in C<$trace> (this also disables the
69893cff
RGS
2331check for C<watchfunction()>. This can be done with
2332
2333 $trace &= ~4;
2334
2335=back
2336
2337=cut
2338
e22ea7cc 2339 # If there's a user-defined DB::watchfunction, call it with the
69893cff
RGS
2340 # current package, filename, and line. The function executes in
2341 # the DB:: package.
e22ea7cc
RF
2342 if ( $trace & 4 ) { # User-installed watch
2343 return
2344 if watchfunction( $package, $filename, $line )
2345 and not $single
2346 and not $was_signal
2347 and not( $trace & ~4 );
69893cff
RGS
2348 } ## end if ($trace & 4)
2349
e22ea7cc 2350 # Pick up any alteration to $signal in the watchfunction, and
69893cff 2351 # turn off the signal now.
6027b9a3 2352 $was_signal = $signal;
69893cff
RGS
2353 $signal = 0;
2354
2355=head2 GETTING READY TO EXECUTE COMMANDS
2356
2357The debugger decides to take control if single-step mode is on, the
2358C<t> command was entered, or the user generated a signal. If the program
2359has fallen off the end, we set things up so that entering further commands
2360won't cause trouble, and we say that the program is over.
2361
2362=cut
2363
8dc67a69
SF
2364 # Make sure that we always print if asked for explicitly regardless
2365 # of $trace_to_depth .
22fc883d 2366 $explicit_stop = ($single || $was_signal);
8dc67a69 2367
69893cff
RGS
2368 # Check to see if we should grab control ($single true,
2369 # trace set appropriately, or we got a signal).
8dc67a69 2370 if ( $explicit_stop || ( $trace & 1 ) ) {
22fc883d 2371 $obj->_DB__grab_control(@_);
69893cff
RGS
2372 } ## end if ($single || ($trace...
2373
2374=pod
2375
2376If there's an action to be executed for the line we stopped at, execute it.
b570d64b 2377If there are any preprompt actions, execute those as well.
e219e2fb
RF
2378
2379=cut
2380
69893cff 2381 # If there's an action, do it now.
05da04df
SF
2382 if ($action) {
2383 $evalarg = $action;
2384 DB::eval();
2385 }
e219e2fb 2386
69893cff
RGS
2387 # Are we nested another level (e.g., did we evaluate a function
2388 # that had a breakpoint in it at the debugger prompt)?
e22ea7cc
RF
2389 if ( $single || $was_signal ) {
2390
69893cff 2391 # Yes, go down a level.
e22ea7cc 2392 local $level = $level + 1;
69893cff
RGS
2393
2394 # Do any pre-prompt actions.
e22ea7cc 2395 foreach $evalarg (@$pre) {
7c54f46a 2396 DB::eval();
e22ea7cc 2397 }
69893cff
RGS
2398
2399 # Complain about too much recursion if we passed the limit.
05da04df
SF
2400 if ($single & 4) {
2401 print $OUT $stack_depth . " levels deep in subroutine calls!\n";
2402 }
69893cff
RGS
2403
2404 # The line we're currently on. Set $incr to -1 to stay here
2405 # until we get a command that tells us to advance.
e22ea7cc
RF
2406 $start = $line;
2407 $incr = -1; # for backward motion.
69893cff
RGS
2408
2409 # Tack preprompt debugger actions ahead of any actual input.
e22ea7cc 2410 @typeahead = ( @$pretype, @typeahead );
69893cff
RGS
2411
2412=head2 WHERE ARE WE?
2413
2414XXX Relocate this section?
2415
2416The debugger normally shows the line corresponding to the current line of
2417execution. Sometimes, though, we want to see the next line, or to move elsewhere
2418in the file. This is done via the C<$incr>, C<$start>, and C<$max> variables.
2419
be9a9b1d
AT
2420C<$incr> controls by how many lines the I<current> line should move forward
2421after a command is executed. If set to -1, this indicates that the I<current>
69893cff
RGS
2422line shouldn't change.
2423
be9a9b1d 2424C<$start> is the I<current> line. It is used for things like knowing where to
69893cff
RGS
2425move forwards or backwards from when doing an C<L> or C<-> command.
2426
2427C<$max> tells the debugger where the last line of the current file is. It's
2428used to terminate loops most often.
2429
2430=head2 THE COMMAND LOOP
2431
2432Most of C<DB::DB> is actually a command parsing and dispatch loop. It comes
2433in two parts:
2434
2435=over 4
2436
be9a9b1d
AT
2437=item *
2438
2439The outer part of the loop, starting at the C<CMD> label. This loop
69893cff
RGS
2440reads a command and then executes it.
2441
be9a9b1d
AT
2442=item *
2443
2444The inner part of the loop, starting at the C<PIPE> label. This part
69893cff
RGS
2445is wholly contained inside the C<CMD> block and only executes a command.
2446Used to handle commands running inside a pager.
2447
2448=back
2449
2450So why have two labels to restart the loop? Because sometimes, it's easier to
2451have a command I<generate> another command and then re-execute the loop to do
2452the new command. This is faster, but perhaps a bit more convoluted.
2453
2454=cut
2455
2456 # The big command dispatch loop. It keeps running until the
2457 # user yields up control again.
2458 #
2459 # If we have a terminal for input, and we get something back
2460 # from readline(), keep on processing.
6b24a4b7
SF
2461 my $piped;
2462 my $selected;
2463
e22ea7cc 2464 CMD:
32bbadc6 2465 while (_DB__read_next_cmd($tid))
69893cff 2466 {
e22ea7cc 2467
8380a245 2468 share($cmd);
69893cff
RGS
2469 # ... try to execute the input as debugger commands.
2470
2471 # Don't stop running.
2472 $single = 0;
2473
2474 # No signal is active.
2475 $signal = 0;
2476
2477 # Handle continued commands (ending with \):
3d7a2a93 2478 if ($cmd =~ s/\\\z/\n/) {
eeb7da96 2479 $cmd .= DB::readline(" cont: ");
e22ea7cc 2480 redo CMD;
3d7a2a93 2481 }
69893cff
RGS
2482
2483=head4 The null command
2484
be9a9b1d 2485A newline entered by itself means I<re-execute the last command>. We grab the
69893cff
RGS
2486command out of C<$laststep> (where it was recorded previously), and copy it
2487back into C<$cmd> to be executed below. If there wasn't any previous command,
2488we'll do nothing below (no command will match). If there was, we also save it
2489in the command history and fall through to allow the command parsing to pick
2490it up.
2491
2492=cut
2493
2494 # Empty input means repeat the last command.
eeb7da96
SF
2495 if ($cmd eq '') {
2496 $cmd = $laststep;
2497 }
e22ea7cc 2498 chomp($cmd); # get rid of the annoying extra newline
eeb7da96
SF
2499 if (length($cmd) >= 2) {
2500 push( @hist, $cmd );
2501 }
e22ea7cc 2502 push( @truehist, $cmd );
2dbd01ad
SF
2503 share(@hist);
2504 share(@truehist);
e22ea7cc
RF
2505
2506 # This is a restart point for commands that didn't arrive
2507 # via direct user input. It allows us to 'redo PIPE' to
2508 # re-execute command processing without reading a new command.
69893cff 2509 PIPE: {
35cd713a 2510 $i = _DB__trim_command_and_return_first_component();
69893cff
RGS
2511
2512=head3 COMMAND ALIASES
2513
2514The debugger can create aliases for commands (these are stored in the
2515C<%alias> hash). Before a command is executed, the command loop looks it up
2516in the alias hash and substitutes the contents of the alias for the command,
2517completely replacing it.
2518
2519=cut
2520
2521 # See if there's an alias for the command, and set it up if so.
e22ea7cc
RF
2522 if ( $alias{$i} ) {
2523
69893cff
RGS
2524 # Squelch signal handling; we want to keep control here
2525 # if something goes loco during the alias eval.
2526 local $SIG{__DIE__};
2527 local $SIG{__WARN__};
2528
2529 # This is a command, so we eval it in the DEBUGGER's
2530 # scope! Otherwise, we can't see the special debugger
2531 # variables, or get to the debugger's subs. (Well, we
2532 # _could_, but why make it even more complicated?)
2533 eval "\$cmd =~ $alias{$i}";
2534 if ($@) {
2535 local $\ = '';
1f874cb6 2536 print $OUT "Couldn't evaluate '$i' alias: $@";
69893cff
RGS
2537 next CMD;
2538 }
2539 } ## end if ($alias{$i})
2540
2541=head3 MAIN-LINE COMMANDS
2542
2543All of these commands work up to and after the program being debugged has
b570d64b 2544terminated.
69893cff
RGS
2545
2546=head4 C<q> - quit
2547
b570d64b 2548Quit the debugger. This entails setting the C<$fall_off_end> flag, so we don't
69893cff
RGS
2549try to execute further, cleaning any restart-related stuff out of the
2550environment, and executing with the last value of C<$?>.
2551
2552=cut
2553
3d7a2a93 2554 if ($cmd eq 'q') {
69893cff
RGS
2555 $fall_off_end = 1;
2556 clean_ENV();
2557 exit $?;
3d7a2a93 2558 }
69893cff 2559
611272bb 2560=head4 C<t> - trace [n]
69893cff
RGS
2561
2562Turn tracing on or off. Inverts the appropriate bit in C<$trace> (q.v.).
611272bb 2563If level is specified, set C<$trace_to_depth>.
69893cff
RGS
2564
2565=cut
2566
9d0b71b3 2567 $obj->_handle_t_command;
69893cff
RGS
2568
2569=head4 C<S> - list subroutines matching/not matching a pattern
2570
2571Walks through C<%sub>, checking to see whether or not to print the name.
2572
2573=cut
2574
9d0b71b3 2575 $obj->_handle_S_command;
69893cff
RGS
2576
2577=head4 C<X> - list variables in current package
2578
b570d64b 2579Since the C<V> command actually processes this, just change this to the
69893cff
RGS
2580appropriate C<V> command and fall through.
2581
69893cff
RGS
2582=head4 C<V> - list variables
2583
b570d64b 2584Uses C<dumpvar.pl> to dump out the current values for selected variables.
69893cff
RGS
2585
2586=cut
2587
1ce985d2 2588 $obj->_handle_V_command_and_X_command;
69893cff
RGS
2589
2590=head4 C<x> - evaluate and print an expression
2591
2592Hands the expression off to C<DB::eval>, setting it up to print the value
2593via C<dumpvar.pl> instead of just printing it directly.
2594
2595=cut
2596
826b9a2e 2597 if ($cmd =~ s#\Ax\b# #) { # Remainder gets done by DB::eval()
e22ea7cc 2598 $onetimeDump = 'dump'; # main::dumpvar shows the output
69893cff
RGS
2599
2600 # handle special "x 3 blah" syntax XXX propagate
2601 # doc back to special variables.
826b9a2e 2602 if ( $cmd =~ s#\A\s*(\d+)(?=\s)# #) {
e22ea7cc
RF
2603 $onetimedumpDepth = $1;
2604 }
826b9a2e 2605 }
69893cff
RGS
2606
2607=head4 C<m> - print methods
2608
2609Just uses C<DB::methods> to determine what methods are available.
2610
2611=cut
2612
826b9a2e 2613 if ($cmd =~ s#\Am\s+([\w:]+)\s*\z# #) {
e22ea7cc
RF
2614 methods($1);
2615 next CMD;
826b9a2e 2616 }
69893cff
RGS
2617
2618 # m expr - set up DB::eval to do the work
826b9a2e 2619 if ($cmd =~ s#\Am\b# #) { # Rest gets done by DB::eval()
e22ea7cc 2620 $onetimeDump = 'methods'; # method output gets used there
826b9a2e 2621 }
69893cff
RGS
2622
2623=head4 C<f> - switch files
2624
2625=cut
2626
2a802473 2627 _DB__handle_f_command();
69893cff
RGS
2628
2629=head4 C<.> - return to last-executed line.
2630
2631We set C<$incr> to -1 to indicate that the debugger shouldn't move ahead,
2632and then we look up the line in the magical C<%dbline> hash.
2633
2634=cut
2635
6115a173 2636 _DB__handle_dot_command($obj);
69893cff
RGS
2637
2638=head4 C<-> - back one window
2639
2640We change C<$start> to be one window back; if we go back past the first line,
2641we set it to be the first line. We ser C<$incr> to put us back at the
2642currently-executing line, and then put a C<l $start +> (list one window from
2643C<$start>) in C<$cmd> to be executed later.
2644
2645=cut
2646
2647 # - - back a window.
d1450c23 2648 $obj->_handle_dash_command;
69893cff 2649
8481f647 2650=head3 PRE-580 COMMANDS VS. NEW COMMANDS: C<a, A, b, B, h, l, L, M, o, O, P, v, w, W, E<lt>, E<lt>E<lt>, E<0x7B>, E<0x7B>E<0x7B>>
69893cff
RGS
2651
2652In Perl 5.8.0, a realignment of the commands was done to fix up a number of
2653problems, most notably that the default case of several commands destroying
2654the user's work in setting watchpoints, actions, etc. We wanted, however, to
2655retain the old commands for those who were used to using them or who preferred
2656them. At this point, we check for the new commands and call C<cmd_wrapper> to
2657deal with them instead of processing them in-line.
2658
2659=cut
2660
2661 # All of these commands were remapped in perl 5.8.0;
e22ea7cc 2662 # we send them off to the secondary dispatcher (see below).
826b9a2e
SF
2663 if (my ($cmd_letter, $my_arg) = $cmd =~ /\A([aAbBeEhilLMoOPvwW]\b|[<>\{]{1,2})\s*(.*)/so) {
2664 &cmd_wrapper( $cmd_letter, $my_arg, $line );
e22ea7cc 2665 next CMD;
826b9a2e 2666 }
69893cff
RGS
2667
2668=head4 C<y> - List lexicals in higher scope
2669
826b9a2e 2670Uses C<PadWalker> to find the lexicals supplied as arguments in a scope
69893cff
RGS
2671above the current one and then displays then using C<dumpvar.pl>.
2672
2673=cut
2674
5c2b78e7 2675 _DB__handle_y_command($obj);
69893cff
RGS
2676
2677=head3 COMMANDS NOT WORKING AFTER PROGRAM ENDS
2678
2679All of the commands below this point don't work after the program being
2680debugged has ended. All of them check to see if the program has ended; this
2681allows the commands to be relocated without worrying about a 'line of
2682demarcation' above which commands can be entered anytime, and below which
2683they can't.
2684
2685=head4 C<n> - single step, but don't trace down into subs
2686
2687Done by setting C<$single> to 2, which forces subs to execute straight through
be9a9b1d 2688when entered (see C<DB::sub>). We also save the C<n> command in C<$laststep>,
826b9a2e 2689so a null command knows what to re-execute.
69893cff
RGS
2690
2691=cut
2692
e22ea7cc 2693 # n - next
73c5e526 2694 $obj->_handle_n_command;
69893cff
RGS
2695
2696=head4 C<s> - single-step, entering subs
2697
826b9a2e 2698Sets C<$single> to 1, which causes C<DB::sub> to continue tracing inside
69893cff
RGS
2699subs. Also saves C<s> as C<$lastcmd>.
2700
2701=cut
2702
cb9d1513 2703 $obj->_handle_s_command;
69893cff
RGS
2704
2705=head4 C<c> - run continuously, setting an optional breakpoint
2706
2707Most of the code for this command is taken up with locating the optional
2708breakpoint, which is either a subroutine name or a line number. We set
2709the appropriate one-time-break in C<@dbline> and then turn off single-stepping
2710in this and all call levels above this one.
2711
2712=cut
2713
2714 # c - start continuous execution.
35cd713a 2715 _DB__handle_c_command($obj);
69893cff
RGS
2716
2717=head4 C<r> - return from a subroutine
2718
2719For C<r> to work properly, the debugger has to stop execution again
2720immediately after the return is executed. This is done by forcing
2721single-stepping to be on in the call level above the current one. If
2722we are printing return values when a C<r> is executed, set C<$doret>
2723appropriately, and force us out of the command loop.
2724
2725=cut
2726
2727 # r - return from the current subroutine.
573b5003 2728 $obj->_handle_r_command;
69893cff 2729
69893cff
RGS
2730=head4 C<T> - stack trace
2731
2732Just calls C<DB::print_trace>.
2733
2734=cut
2735
d4038e14 2736 $obj->_handle_T_command;
69893cff
RGS
2737
2738=head4 C<w> - List window around current line.
2739
2740Just calls C<DB::cmd_w>.
2741
2742=cut
2743
b6e88520 2744 $obj->_handle_w_command;
69893cff
RGS
2745
2746=head4 C<W> - watch-expression processing.
2747
b570d64b 2748Just calls C<DB::cmd_W>.
69893cff
RGS
2749
2750=cut
2751
25953301 2752 $obj->_handle_W_command;
69893cff
RGS
2753
2754=head4 C</> - search forward for a string in the source
2755
ef18ae63 2756We take the argument and treat it as a pattern. If it turns out to be a
69893cff 2757bad one, we return the error we got from trying to C<eval> it and exit.
ef18ae63 2758If not, we create some code to do the search and C<eval> it so it can't
69893cff
RGS
2759mess us up.
2760
2761=cut
2762
a4d311a3 2763 _DB__handle_forward_slash_command($obj);
69893cff
RGS
2764
2765=head4 C<?> - search backward for a string in the source
2766
2767Same as for C</>, except the loop runs backwards.
2768
2769=cut
2770
11f0f050 2771 _DB__handle_question_mark_command($obj);
69893cff
RGS
2772
2773=head4 C<$rc> - Recall command
2774
2775Manages the commands in C<@hist> (which is created if C<Term::ReadLine> reports
2776that the terminal supports history). It find the the command required, puts it
2777into C<$cmd>, and redoes the loop to execute it.
2778
2779=cut
2780
e22ea7cc 2781 # $rc - recall command.
14f38b27 2782 $obj->_handle_rc_recall_command;
69893cff
RGS
2783
2784=head4 C<$sh$sh> - C<system()> command
2785
2786Calls the C<DB::system()> to handle the command. This keeps the C<STDIN> and
2787C<STDOUT> from getting messed up.
2788
2789=cut
2790
2791 # $sh$sh - run a shell command (if it's all ASCII).
2792 # Can't run shell commands with Unicode in the debugger, hmm.
ef18ae63 2793 if (my ($arg) = $cmd =~ m#\A$sh$sh\s*(.*)#ms) {
e22ea7cc 2794
69893cff 2795 # System it.
6bffb264 2796 DB::system($arg);
e22ea7cc 2797 next CMD;
ef18ae63 2798 }
69893cff
RGS
2799
2800=head4 C<$rc I<pattern> $rc> - Search command history
2801
2802Another command to manipulate C<@hist>: this one searches it with a pattern.
be9a9b1d 2803If a command is found, it is placed in C<$cmd> and executed via C<redo>.
69893cff
RGS
2804
2805=cut
2806
0d2c714c 2807 $obj->_handle_rc_search_history_command;
69893cff 2808
ef18ae63 2809=head4 C<$sh> - Invoke a shell
69893cff
RGS
2810
2811Uses C<DB::system> to invoke a shell.
2812
2813=cut
2814
2815 # $sh - start a shell.
ef18ae63 2816 if ($cmd =~ /\A$sh\z/) {
e22ea7cc 2817
69893cff
RGS
2818 # Run the user's shell. If none defined, run Bourne.
2819 # We resume execution when the shell terminates.
e22ea7cc
RF
2820 &system( $ENV{SHELL} || "/bin/sh" );
2821 next CMD;
ef18ae63 2822 }
69893cff
RGS
2823
2824=head4 C<$sh I<command>> - Force execution of a command in a shell
2825
2826Like the above, but the command is passed to the shell. Again, we use
2827C<DB::system> to avoid problems with C<STDIN> and C<STDOUT>.
2828
2829=cut
2830
2831 # $sh command - start a shell and run a command in it.
ef18ae63 2832 if (my ($arg) = $cmd =~ m#\A$sh\s*(.*)#ms) {
e22ea7cc
RF
2833
2834 # XXX: using csh or tcsh destroys sigint retvals!
2835 #&system($1); # use this instead
69893cff
RGS
2836
2837 # use the user's shell, or Bourne if none defined.
ef18ae63 2838 &system( $ENV{SHELL} || "/bin/sh", "-c", $arg );
e22ea7cc 2839 next CMD;
ef18ae63 2840 }
69893cff
RGS
2841
2842=head4 C<H> - display commands in history
2843
2844Prints the contents of C<@hist> (if any).
2845
2846=cut
2847
ef18ae63 2848 if ($cmd =~ /\AH\b\s*\*/) {
7fddc82f
RF
2849 @hist = @truehist = ();
2850 print $OUT "History cleansed\n";
2851 next CMD;
ef18ae63 2852 }
e22ea7cc 2853
ef18ae63
SF
2854 if (my ($num)
2855 = $cmd =~ /\AH\b\s*(?:-(\d+))?/) {
e22ea7cc
RF
2856
2857 # Anything other than negative numbers is ignored by
69893cff 2858 # the (incorrect) pattern, so this test does nothing.
ef18ae63 2859 $end = $num ? ( $#hist - $num ) : 0;
69893cff
RGS
2860
2861 # Set to the minimum if less than zero.
e22ea7cc 2862 $hist = 0 if $hist < 0;
69893cff 2863
e22ea7cc 2864 # Start at the end of the array.
69893cff
RGS
2865 # Stay in while we're still above the ending value.
2866 # Tick back by one each time around the loop.
72d7d80d 2867 for ( $i = $#hist ; $i > $end ; $i-- ) {
69893cff
RGS
2868
2869 # Print the command unless it has no arguments.
e22ea7cc
RF
2870 print $OUT "$i: ", $hist[$i], "\n"
2871 unless $hist[$i] =~ /^.?$/;
2872 }
2873 next CMD;
ef18ae63 2874 }
69893cff
RGS
2875
2876=head4 C<man, doc, perldoc> - look up documentation
2877
2878Just calls C<runman()> to print the appropriate document.
2879
2880=cut
2881
e22ea7cc 2882 # man, perldoc, doc - show manual pages.
ef18ae63
SF
2883 if (my ($man_page)
2884 = $cmd =~ /\A(?:man|(?:perl)?doc)\b(?:\s+([^(]*))?\z/) {
2885 runman($man_page);
e22ea7cc 2886 next CMD;
ef18ae63 2887 }
69893cff
RGS
2888
2889=head4 C<p> - print
2890
2891Builds a C<print EXPR> expression in the C<$cmd>; this will get executed at
2892the bottom of the loop.
2893
2894=cut
2895
ef18ae63 2896 my $print_cmd = 'print {$DB::OUT} ';
69893cff 2897 # p - print (no args): print $_.
ef18ae63
SF
2898 if ($cmd eq 'p') {
2899 $cmd = $print_cmd . '$_';
2900 }
69893cff
RGS
2901
2902 # p - print the given expression.
ef18ae63 2903 $cmd =~ s/\Ap\b/$print_cmd /;
69893cff
RGS
2904
2905=head4 C<=> - define command alias
2906
2907Manipulates C<%alias> to add or list command aliases.
2908
2909=cut
2910
e22ea7cc 2911 # = - set up a command alias.
ef18ae63 2912 if ($cmd =~ s/\A=\s*//) {
e22ea7cc
RF
2913 my @keys;
2914 if ( length $cmd == 0 ) {
2915
69893cff 2916 # No args, get current aliases.
e22ea7cc
RF
2917 @keys = sort keys %alias;
2918 }
2919 elsif ( my ( $k, $v ) = ( $cmd =~ /^(\S+)\s+(\S.*)/ ) ) {
2920
69893cff
RGS
2921 # Creating a new alias. $k is alias name, $v is
2922 # alias value.
2923
e22ea7cc
RF
2924 # can't use $_ or kill //g state
2925 for my $x ( $k, $v ) {
2926
2927 # Escape "alarm" characters.
2928 $x =~ s/\a/\\a/g;
2929 }
69893cff
RGS
2930
2931 # Substitute key for value, using alarm chars
e22ea7cc 2932 # as separators (which is why we escaped them in
69893cff 2933 # the command).
e22ea7cc 2934 $alias{$k} = "s\a$k\a$v\a";
69893cff
RGS
2935
2936 # Turn off standard warn and die behavior.
e22ea7cc
RF
2937 local $SIG{__DIE__};
2938 local $SIG{__WARN__};
69893cff
RGS
2939
2940 # Is it valid Perl?
e22ea7cc
RF
2941 unless ( eval "sub { s\a$k\a$v\a }; 1" ) {
2942
69893cff 2943 # Nope. Bad alias. Say so and get out.
e22ea7cc
RF
2944 print $OUT "Can't alias $k to $v: $@\n";
2945 delete $alias{$k};
2946 next CMD;
2947 }
2948
69893cff 2949 # We'll only list the new one.
e22ea7cc 2950 @keys = ($k);
69893cff
RGS
2951 } ## end elsif (my ($k, $v) = ($cmd...
2952
2953 # The argument is the alias to list.
e22ea7cc
RF
2954 else {
2955 @keys = ($cmd);
2956 }
69893cff
RGS
2957
2958 # List aliases.
e22ea7cc
RF
2959 for my $k (@keys) {
2960
98dc9551 2961 # Messy metaquoting: Trim the substitution code off.
69893cff
RGS
2962 # We use control-G as the delimiter because it's not
2963 # likely to appear in the alias.
e22ea7cc
RF
2964 if ( ( my $v = $alias{$k} ) =~ s\as\a$k\a(.*)\a$\a1\a ) {
2965
69893cff 2966 # Print the alias.
e22ea7cc
RF
2967 print $OUT "$k\t= $1\n";
2968 }
2969 elsif ( defined $alias{$k} ) {
2970
69893cff 2971 # Couldn't trim it off; just print the alias code.
e22ea7cc
RF
2972 print $OUT "$k\t$alias{$k}\n";
2973 }
2974 else {
2975
69893cff 2976 # No such, dude.
e22ea7cc
RF
2977 print "No alias for $k\n";
2978 }
69893cff 2979 } ## end for my $k (@keys)
e22ea7cc 2980 next CMD;
ef18ae63 2981 }
69893cff
RGS
2982
2983=head4 C<source> - read commands from a file.
2984
2985Opens a lexical filehandle and stacks it on C<@cmdfhs>; C<DB::readline> will
2986pick it up.
2987
2988=cut
2989
e22ea7cc 2990 # source - read commands from a file (or pipe!) and execute.
ef18ae63
SF
2991 if (my ($sourced_fn) = $cmd =~ /\Asource\s+(.*\S)/) {
2992 if ( open my $fh, $sourced_fn ) {
e22ea7cc 2993
69893cff 2994 # Opened OK; stick it in the list of file handles.
e22ea7cc
RF
2995 push @cmdfhs, $fh;
2996 }
2997 else {
2998
2999 # Couldn't open it.
ef18ae63 3000 &warn("Can't execute '$sourced_fn': $!\n");
e22ea7cc
RF
3001 }
3002 next CMD;
ef18ae63 3003 }
69893cff 3004
ef18ae63
SF
3005 if (my ($which_cmd, $position)
3006 = $cmd =~ /^(enable|disable)\s+(\S+)\s*$/) {
e09195af
SF
3007
3008 my ($fn, $line_num);
3009 if ($position =~ m{\A\d+\z})
3010 {
3011 $fn = $filename;
3012 $line_num = $position;
3013 }
ef18ae63
SF
3014 elsif (my ($new_fn, $new_line_num)
3015 = $position =~ m{\A(.*):(\d+)\z}) {
3016 ($fn, $line_num) = ($new_fn, $new_line_num);
e09195af
SF
3017 }
3018 else
3019 {
3020 &warn("Wrong spec for enable/disable argument.\n");
3021 }
3022
3023 if (defined($fn)) {
3024 if (_has_breakpoint_data_ref($fn, $line_num)) {
3025 _set_breakpoint_enabled_status($fn, $line_num,
ef18ae63 3026 ($which_cmd eq 'enable' ? 1 : '')
e09195af
SF
3027 );
3028 }
3029 else {
3030 &warn("No breakpoint set at ${fn}:${line_num}\n");
3031 }
3032 }
3033
3034 next CMD;
ef18ae63 3035 }
e09195af 3036
69893cff
RGS
3037=head4 C<save> - send current history to a file
3038
3039Takes the complete history, (not the shrunken version you see with C<H>),
3040and saves it to the given filename, so it can be replayed using C<source>.
3041
3042Note that all C<^(save|source)>'s are commented out with a view to minimise recursion.
3043
3044=cut
3045
3046 # save source - write commands to a file for later use
ef18ae63
SF
3047 if (my ($new_fn) = $cmd =~ /\Asave\s*(.*)\z/) {
3048 my $filename = $new_fn || '.perl5dbrc'; # default?
3049 if ( open my $fh, '>', $filename ) {
e22ea7cc
RF
3050
3051 # chomp to remove extraneous newlines from source'd files
3052 chomp( my @truelist =
3053 map { m/^\s*(save|source)/ ? "#$_" : $_ }
3054 @truehist );
3055 print $fh join( "\n", @truelist );
69893cff 3056 print "commands saved in $file\n";
e22ea7cc
RF
3057 }
3058 else {
ef18ae63 3059 &warn("Can't save debugger commands in '$new_fn': $!\n");
69893cff
RGS
3060 }
3061 next CMD;
ef18ae63 3062 }
69893cff 3063
7fddc82f
RF
3064=head4 C<R> - restart
3065
ef18ae63 3066Restart the debugger session.
7fddc82f
RF
3067
3068=head4 C<rerun> - rerun the current session
3069
3070Return to any given position in the B<true>-history list
3071
3072=cut
3073
3074 # R - restart execution.
3075 # rerun - controlled restart execution.
ff41e38d
SF
3076 if (my ($cmd_cmd, $cmd_params) =
3077 $cmd =~ /\A((?:R)|(?:rerun\s*(.*)))\z/) {
3078 my @args = ($cmd_cmd eq 'R' ? restart() : rerun($cmd_params));
7fddc82f 3079
ca28b541
AP
3080 # Close all non-system fds for a clean restart. A more
3081 # correct method would be to close all fds that were not
3082 # open when the process started, but this seems to be
3083 # hard. See "debugger 'R'estart and open database
3084 # connections" on p5p.
3085
47d3bbda 3086 my $max_fd = 1024; # default if POSIX can't be loaded
ca28b541 3087 if (eval { require POSIX }) {
5332cc68 3088 eval { $max_fd = POSIX::sysconf(POSIX::_SC_OPEN_MAX()) };
ca28b541
AP
3089 }
3090
3091 if (defined $max_fd) {
3092 foreach ($^F+1 .. $max_fd-1) {
3093 next unless open FD_TO_CLOSE, "<&=$_";
3094 close(FD_TO_CLOSE);
3095 }
3096 }
3097
7fddc82f
RF
3098 # And run Perl again. We use exec() to keep the
3099 # PID stable (and that way $ini_pids is still valid).
3100 exec(@args) || print $OUT "exec failed: $!\n";
3101
3102 last CMD;
ff41e38d 3103 }
7fddc82f 3104
69893cff
RGS
3105=head4 C<|, ||> - pipe output through the pager.
3106
be9a9b1d 3107For C<|>, we save C<OUT> (the debugger's output filehandle) and C<STDOUT>
69893cff
RGS
3108(the program's standard output). For C<||>, we only save C<OUT>. We open a
3109pipe to the pager (restoring the output filehandles if this fails). If this
b570d64b 3110is the C<|> command, we also set up a C<SIGPIPE> handler which will simply
69893cff
RGS
3111set C<$signal>, sending us back into the debugger.
3112
3113We then trim off the pipe symbols and C<redo> the command loop at the
3114C<PIPE> label, causing us to evaluate the command in C<$cmd> without
3115reading another.
3116
3117=cut
3118
3119 # || - run command in the pager, with output to DB::OUT.
ff41e38d 3120 if ($cmd =~ m#\A\|\|?\s*[^|]#) {
e22ea7cc
RF
3121 if ( $pager =~ /^\|/ ) {
3122
69893cff 3123 # Default pager is into a pipe. Redirect I/O.
e22ea7cc
RF
3124 open( SAVEOUT, ">&STDOUT" )
3125 || &warn("Can't save STDOUT");
3126 open( STDOUT, ">&OUT" )
3127 || &warn("Can't redirect STDOUT");
69893cff 3128 } ## end if ($pager =~ /^\|/)
e22ea7cc
RF
3129 else {
3130
69893cff 3131 # Not into a pipe. STDOUT is safe.
e22ea7cc
RF
3132 open( SAVEOUT, ">&OUT" ) || &warn("Can't save DB::OUT");
3133 }
69893cff
RGS
3134
3135 # Fix up environment to record we have less if so.
e22ea7cc
RF
3136 fix_less();
3137
3138 unless ( $piped = open( OUT, $pager ) ) {
69893cff 3139
69893cff 3140 # Couldn't open pipe to pager.
1f874cb6 3141 &warn("Can't pipe output to '$pager'");
e22ea7cc
RF
3142 if ( $pager =~ /^\|/ ) {
3143
69893cff 3144 # Redirect I/O back again.
e22ea7cc
RF
3145 open( OUT, ">&STDOUT" ) # XXX: lost message
3146 || &warn("Can't restore DB::OUT");
3147 open( STDOUT, ">&SAVEOUT" )
3148 || &warn("Can't restore STDOUT");
3149 close(SAVEOUT);
69893cff 3150 } ## end if ($pager =~ /^\|/)
e22ea7cc
RF
3151 else {
3152
69893cff 3153 # Redirect I/O. STDOUT already safe.
e22ea7cc
RF
3154 open( OUT, ">&STDOUT" ) # XXX: lost message
3155 || &warn("Can't restore DB::OUT");
3156 }
3157 next CMD;
69893cff
RGS
3158 } ## end unless ($piped = open(OUT,...
3159
3160 # Set up broken-pipe handler if necessary.
e22ea7cc
RF
3161 $SIG{PIPE} = \&DB::catch
3162 if $pager =~ /^\|/
3163 && ( "" eq $SIG{PIPE} || "DEFAULT" eq $SIG{PIPE} );
69893cff 3164
70c9432b
SF
3165 OUT->autoflush(1);
3166 # Save current filehandle, and put it back.
e22ea7cc 3167 $selected = select(OUT);
69893cff 3168 # Don't put it back if pager was a pipe.
e22ea7cc 3169 select($selected), $selected = "" unless $cmd =~ /^\|\|/;
69893cff
RGS
3170
3171 # Trim off the pipe symbols and run the command now.
ff41e38d 3172 $cmd =~ s#\A\|+\s*##;
e22ea7cc 3173 redo PIPE;
ff41e38d 3174 }
69893cff
RGS
3175
3176=head3 END OF COMMAND PARSING
3177
ff41e38d
SF
3178Anything left in C<$cmd> at this point is a Perl expression that we want to
3179evaluate. We'll always evaluate in the user's context, and fully qualify
69893cff
RGS
3180any variables we might want to address in the C<DB> package.
3181
3182=cut
3183
3184 # t - turn trace on.
ff41e38d
SF
3185 if ($cmd =~ s#\At\s+(\d+)?#\$DB::trace |= 1;\n#) {
3186 my $trace_arg = $1;
3187 $trace_to_depth = $trace_arg ? $stack_depth||0 + $1 : 1E9;
3188 }
69893cff
RGS
3189
3190 # s - single-step. Remember the last command was 's'.
ff41e38d
SF
3191 if ($cmd =~ s/\As\s/\$DB::single = 1;\n/) {
3192 $laststep = 's';
3193 }
69893cff
RGS
3194
3195 # n - single-step, but not into subs. Remember last command
e22ea7cc 3196 # was 'n'.
ff41e38d
SF
3197 if ($cmd =~ s#\An\s#\$DB::single = 2;\n#) {
3198 $laststep = 'n';
3199 }
69893cff 3200
e22ea7cc 3201 } # PIPE:
69893cff 3202
e22ea7cc 3203 # Make sure the flag that says "the debugger's running" is
69893cff 3204 # still on, to make sure we get control again.
e22ea7cc 3205 $evalarg = "\$^D = \$^D | \$DB::db_stop;\n$cmd";
69893cff
RGS
3206
3207 # Run *our* eval that executes in the caller's context.
7c54f46a 3208 DB::eval();
69893cff
RGS
3209
3210 # Turn off the one-time-dump stuff now.
e22ea7cc
RF
3211 if ($onetimeDump) {
3212 $onetimeDump = undef;
69893cff 3213 $onetimedumpDepth = undef;
e22ea7cc
RF
3214 }
3215 elsif ( $term_pid == $$ ) {
8380a245 3216 eval { # May run under miniperl, when not available...
c7e68384
IZ
3217 STDOUT->flush();
3218 STDERR->flush();
8380a245 3219 };
e22ea7cc 3220
69893cff 3221 # XXX If this is the master pid, print a newline.
8380a245 3222 print {$OUT} "\n";
e22ea7cc
RF
3223 }
3224 } ## end while (($term || &setterm...
69893cff
RGS
3225
3226=head3 POST-COMMAND PROCESSING
3227
3228After each command, we check to see if the command output was piped anywhere.
3229If so, we go through the necessary code to unhook the pipe and go back to
3230our standard filehandles for input and output.
3231
3232=cut
3233
e22ea7cc 3234 continue { # CMD:
69893cff
RGS
3235
3236 # At the end of every command:
e22ea7cc
RF
3237 if ($piped) {
3238
69893cff 3239 # Unhook the pipe mechanism now.
e22ea7cc
RF
3240 if ( $pager =~ /^\|/ ) {
3241
69893cff 3242 # No error from the child.
e22ea7cc 3243 $? = 0;
69893cff 3244
e22ea7cc
RF
3245 # we cannot warn here: the handle is missing --tchrist
3246 close(OUT) || print SAVEOUT "\nCan't close DB::OUT\n";
69893cff 3247
e22ea7cc 3248 # most of the $? crud was coping with broken cshisms
69893cff 3249 # $? is explicitly set to 0, so this never runs.
e22ea7cc 3250 if ($?) {
1f874cb6 3251 print SAVEOUT "Pager '$pager' failed: ";
e22ea7cc
RF
3252 if ( $? == -1 ) {
3253 print SAVEOUT "shell returned -1\n";
3254 }
3255 elsif ( $? >> 8 ) {
3256 print SAVEOUT ( $? & 127 )
3257 ? " (SIG#" . ( $? & 127 ) . ")"
3258 : "", ( $? & 128 ) ? " -- core dumped" : "", "\n";
3259 }
3260 else {
3261 print SAVEOUT "status ", ( $? >> 8 ), "\n";
3262 }
69893cff
RGS
3263 } ## end if ($?)
3264
e22ea7cc 3265 # Reopen filehandle for our output (if we can) and
69893cff 3266 # restore STDOUT (if we can).
e22ea7cc
RF
3267 open( OUT, ">&STDOUT" ) || &warn("Can't restore DB::OUT");
3268 open( STDOUT, ">&SAVEOUT" )
3269 || &warn("Can't restore STDOUT");
69893cff
RGS
3270
3271 # Turn off pipe exception handler if necessary.
e22ea7cc 3272 $SIG{PIPE} = "DEFAULT" if $SIG{PIPE} eq \&DB::catch;
69893cff 3273
e22ea7cc
RF
3274 # Will stop ignoring SIGPIPE if done like nohup(1)
3275 # does SIGINT but Perl doesn't give us a choice.
69893cff 3276 } ## end if ($pager =~ /^\|/)
e22ea7cc
RF
3277 else {
3278
69893cff 3279 # Non-piped "pager". Just restore STDOUT.
e22ea7cc
RF
3280 open( OUT, ">&SAVEOUT" ) || &warn("Can't restore DB::OUT");
3281 }
69893cff
RGS
3282
3283 # Close filehandle pager was using, restore the normal one
3284 # if necessary,
3285 close(SAVEOUT);
e22ea7cc 3286 select($selected), $selected = "" unless $selected eq "";
69893cff
RGS
3287
3288 # No pipes now.
e22ea7cc 3289 $piped = "";
69893cff 3290 } ## end if ($piped)
e22ea7cc 3291 } # CMD:
69893cff
RGS
3292
3293=head3 COMMAND LOOP TERMINATION
3294
3295When commands have finished executing, we come here. If the user closed the
3296input filehandle, we turn on C<$fall_off_end> to emulate a C<q> command. We
3297evaluate any post-prompt items. We restore C<$@>, C<$!>, C<$^E>, C<$,>, C<$/>,
3298C<$\>, and C<$^W>, and return a null list as expected by the Perl interpreter.
3299The interpreter will then execute the next line and then return control to us
3300again.
3301
3302=cut
3303
3304 # No more commands? Quit.
1f874cb6 3305 $fall_off_end = 1 unless defined $cmd; # Emulate 'q' on EOF
69893cff
RGS
3306
3307 # Evaluate post-prompt commands.
e22ea7cc 3308 foreach $evalarg (@$post) {
7c54f46a 3309 DB::eval();
e22ea7cc
RF
3310 }
3311 } # if ($single || $signal)
69893cff
RGS
3312
3313 # Put the user's globals back where you found them.
e22ea7cc 3314 ( $@, $!, $^E, $,, $/, $\, $^W ) = @saved;
69893cff
RGS
3315 ();
3316} ## end sub DB
3317
22fc883d
SF
3318package DB::Obj;
3319
3320sub new {
3321 my $class = shift;
3322
3323 my $self = bless {}, $class;
3324
3325 $self->_init(@_);
3326
3327 return $self;
3328}
3329
3330sub _init {
3331 my ($self, $args) = @_;
3332
3333 %{$self} = (%$self, %$args);
3334
3335 return;
3336}
3337
3338{
3339 no strict 'refs';
a4d311a3
SF
3340 foreach my $slot_name (qw(
3341 after explicit_stop infix pat position prefix i_cmd
3342 )) {
22fc883d
SF
3343 my $slot = $slot_name;
3344 *{$slot} = sub {
3345 my $self = shift;
3346
3347 if (@_) {
3348 ${ $self->{$slot} } = shift;
3349 }
3350
3351 return ${ $self->{$slot} };
3352 };
8def6eff
SF
3353
3354 *{"append_to_$slot"} = sub {
3355 my $self = shift;
3356 my $s = shift;
3357
3358 return $self->$slot($self->$slot . $s);
3359 };
22fc883d
SF
3360 }
3361}
3362
3363sub _DB_on_init__initialize_globals
3364{
3365 my $self = shift;
3366
3367 # Check for whether we should be running continuously or not.
3368 # _After_ the perl program is compiled, $single is set to 1:
ebd0282e 3369 if ( $single and not $second_time++ ) {
22fc883d
SF
3370
3371 # Options say run non-stop. Run until we get an interrupt.
ebd0282e 3372 if ($runnonstop) { # Disable until signal
22fc883d
SF
3373 # If there's any call stack in place, turn off single
3374 # stepping into subs throughout the stack.
8ad70697
SF
3375 for my $i (0 .. $stack_depth) {
3376 $stack[ $i ] &= ~1;
22fc883d
SF
3377 }
3378
3379 # And we are now no longer in single-step mode.
ebd0282e 3380 $single = 0;
22fc883d
SF
3381
3382 # If we simply returned at this point, we wouldn't get
3383 # the trace info. Fall on through.
3384 # return;
3385 } ## end if ($runnonstop)
3386
8ad70697 3387 elsif ($ImmediateStop) {
22fc883d
SF
3388
3389 # We are supposed to stop here; XXX probably a break.
8ad70697 3390 $ImmediateStop = 0; # We've processed it; turn it off
ebd0282e 3391 $signal = 1; # Simulate an interrupt to force
22fc883d
SF
3392 # us into the command loop
3393 }
3394 } ## end if ($single and not $second_time...
3395
3396 # If we're in single-step mode, or an interrupt (real or fake)
3397 # has occurred, turn off non-stop mode.
ebd0282e 3398 $runnonstop = 0 if $single or $signal;
22fc883d
SF
3399
3400 return;
3401}
3402
3403sub _DB__handle_watch_expressions
3404{
3405 my $self = shift;
3406
931ac036 3407 if ( $trace & 2 ) {
8ad70697
SF
3408 for my $n (0 .. $#to_watch) {
3409 $evalarg = $to_watch[$n];
3410 local $onetimeDump; # Tell DB::eval() to not output results
22fc883d
SF
3411
3412 # Fix context DB::eval() wants to return an array, but
3413 # we need a scalar here.
7c54f46a 3414 my ($val) = join( "', '", DB::eval() );
22fc883d
SF
3415 $val = ( ( defined $val ) ? "'$val'" : 'undef' );
3416
3417 # Did it change?
8ad70697 3418 if ( $val ne $old_watch[$n] ) {
22fc883d
SF
3419
3420 # Yep! Show the difference, and fake an interrupt.
ebd0282e 3421 $signal = 1;
8ad70697
SF
3422 print {$OUT} <<EOP;
3423Watchpoint $n:\t$to_watch[$n] changed:
3424 old value:\t$old_watch[$n]
22fc883d
SF
3425 new value:\t$val
3426EOP
8ad70697 3427 $old_watch[$n] = $val;
22fc883d
SF
3428 } ## end if ($val ne $old_watch...
3429 } ## end for my $n (0 ..
3430 } ## end if ($trace & 2)
3431
3432 return;
3433}
3434
ad46ac70
SF
3435sub _my_print_lineinfo
3436{
3437 my ($self, $i, $incr_pos) = @_;
3438
18b5b545 3439 if ($frame) {
ad46ac70 3440 # Print it indented if tracing is on.
8ad70697 3441 DB::print_lineinfo( ' ' x $stack_depth,
ad46ac70
SF
3442 "$i:\t$DB::dbline[$i]" . $self->after );
3443 }
3444 else {
3445 DB::depth_print_lineinfo($self->explicit_stop, $incr_pos);
3446 }
3447}
3448
44a07e3e 3449sub _curr_line {
18b5b545 3450 return $DB::dbline[$line];
44a07e3e
SF
3451}
3452
22fc883d
SF
3453sub _DB__grab_control
3454{
3455 my $self = shift;
3456
3457 # Yes, grab control.
7793e5c2 3458 if ($slave_editor) {
22fc883d
SF
3459
3460 # Tell the editor to update its position.
18b5b545 3461 $self->position("\032\032${DB::filename}:$line:0\n");
22fc883d
SF
3462 DB::print_lineinfo($self->position());
3463 }
3464
3465=pod
3466
3467Special check: if we're in package C<DB::fake>, we've gone through the
3468C<END> block at least once. We set up everything so that we can continue
3469to enter commands and have a valid context to be in.
3470
3471=cut
3472
3473 elsif ( $DB::package eq 'DB::fake' ) {
3474
3475 # Fallen off the end already.
3476 if (!$DB::term) {
3477 DB::setterm();
3478 }
3479
3480 DB::print_help(<<EOP);
3481Debugged program terminated. Use B<q> to quit or B<R> to restart,
3482use B<o> I<inhibit_exit> to avoid stopping after program termination,
3483B<h q>, B<h R> or B<h o> to get additional info.
3484EOP
3485
3486 # Set the DB::eval context appropriately.
3487 $DB::package = 'main';
3488 $DB::usercontext = DB::_calc_usercontext($DB::package);
3489 } ## end elsif ($package eq 'DB::fake')
3490
3491=pod
3492
3493If the program hasn't finished executing, we scan forward to the
3494next executable line, print that out, build the prompt from the file and line
3495number information, and print that.
3496
3497=cut
3498
3499 else {
3500
3501
3502 # Still somewhere in the midst of execution. Set up the
3503 # debugger prompt.
3504 $DB::sub =~ s/\'/::/; # Swap Perl 4 package separators (') to
3505 # Perl 5 ones (sorry, we don't print Klingon
3506 #module names)
3507
3508 $self->prefix($DB::sub =~ /::/ ? "" : ($DB::package . '::'));
8def6eff 3509 $self->append_to_prefix( "$DB::sub(${DB::filename}:" );
44a07e3e 3510 $self->after( $self->_curr_line =~ /\n$/ ? '' : "\n" );
22fc883d
SF
3511
3512 # Break up the prompt if it's really long.
3513 if ( length($self->prefix()) > 30 ) {
18b5b545 3514 $self->position($self->prefix . "$line):\n$line:\t" . $self->_curr_line . $self->after);
22fc883d
SF
3515 $self->prefix("");
3516 $self->infix(":\t");
3517 }
3518 else {
3519 $self->infix("):\t");
3520 $self->position(
18b5b545 3521 $self->prefix . $line. $self->infix
44a07e3e 3522 . $self->_curr_line . $self->after
22fc883d
SF
3523 );
3524 }
3525
3526 # Print current line info, indenting if necessary.
18b5b545 3527 $self->_my_print_lineinfo($line, $self->position);
22fc883d 3528
44a07e3e
SF
3529 my $i;
3530 my $line_i = sub { return $DB::dbline[$i]; };
3531
22fc883d
SF
3532 # Scan forward, stopping at either the end or the next
3533 # unbreakable line.
18b5b545 3534 for ( $i = $line + 1 ; $i <= $DB::max && $line_i->() == 0 ; ++$i )
22fc883d
SF
3535 { #{ vi
3536
3537 # Drop out on null statements, block closers, and comments.
44a07e3e 3538 last if $line_i->() =~ /^\s*[\;\}\#\n]/;
22fc883d
SF
3539
3540 # Drop out if the user interrupted us.
ebd0282e 3541 last if $signal;
22fc883d
SF
3542
3543 # Append a newline if the line doesn't have one. Can happen
3544 # in eval'ed text, for instance.
44a07e3e 3545 $self->after( $line_i->() =~ /\n$/ ? '' : "\n" );
22fc883d
SF
3546
3547 # Next executable line.
44a07e3e 3548 my $incr_pos = $self->prefix . $i . $self->infix . $line_i->()
22fc883d 3549 . $self->after;
8def6eff 3550 $self->append_to_position($incr_pos);
ad46ac70 3551 $self->_my_print_lineinfo($i, $incr_pos);
22fc883d
SF
3552 } ## end for ($i = $line + 1 ; $i...
3553 } ## end else [ if ($slave_editor)
3554
3555 return;
3556}
3557
174f9c5e
SF
3558sub _handle_t_command {
3559 if (my ($levels) = $DB::cmd =~ /\At(?:\s+(\d+))?\z/) {
931ac036 3560 $trace ^= 1;
174f9c5e 3561 local $\ = '';
8ad70697
SF
3562 $DB::trace_to_depth = $levels ? $stack_depth + $levels : 1E9;
3563 print {$OUT} "Trace = "
931ac036 3564 . ( ( $trace & 1 )
174f9c5e
SF
3565 ? ( $levels ? "on (to level $DB::trace_to_depth)" : "on" )
3566 : "off" ) . "\n";
3567 next CMD;
3568 }
3569
3570 return;
3571}
3572
9d0b71b3
SF
3573
3574sub _handle_S_command {
3575 if (my ($print_all_subs, $should_reverse, $Spatt)
3576 = $DB::cmd =~ /\AS(\s+(!)?(.+))?\z/) {
3577 # $Spatt is the pattern (if any) to use.
3578 # Reverse scan?
3579 my $Srev = defined $should_reverse;
3580 # No args - print all subs.
3581 my $Snocheck = !defined $print_all_subs;
3582
3583 # Need to make these sane here.
3584 local $\ = '';
3585 local $, = '';
3586
3587 # Search through the debugger's magical hash of subs.
3588 # If $nocheck is true, just print the sub name.
3589 # Otherwise, check it against the pattern. We then use
3590 # the XOR trick to reverse the condition as required.
3591 foreach $subname ( sort( keys %sub ) ) {
3592 if ( $Snocheck or $Srev ^ ( $subname =~ /$Spatt/ ) ) {
3593 print $OUT $subname, "\n";
3594 }
3595 }
3596 next CMD;
3597 }
3598
3599 return;
3600}
3601
1ce985d2
SF
3602sub _handle_V_command_and_X_command {
3603
3604 $DB::cmd =~ s/^X\b/V $DB::package/;
3605
3606 # Bare V commands get the currently-being-debugged package
3607 # added.
3608 if ($DB::cmd eq "V") {
3609 $DB::cmd = "V $DB::package";
3610 }
3611
3612 # V - show variables in package.
3613 if (my ($new_packname, $new_vars_str) =
3614 $DB::cmd =~ /\AV\b\s*(\S+)\s*(.*)/) {
3615
3616 # Save the currently selected filehandle and
3617 # force output to debugger's filehandle (dumpvar
3618 # just does "print" for output).
3619 my $savout = select($OUT);
3620
3621 # Grab package name and variables to dump.
3622 $packname = $new_packname;
3623 my @vars = split( ' ', $new_vars_str );
3624
3625 # If main::dumpvar isn't here, get it.
3626 do 'dumpvar.pl' || die $@ unless defined &main::dumpvar;
3627 if ( defined &main::dumpvar ) {
3628
3629 # We got it. Turn off subroutine entry/exit messages
3630 # for the moment, along with return values.
3631 local $frame = 0;
3632 local $doret = -2;
3633
3634 # must detect sigpipe failures - not catching
3635 # then will cause the debugger to die.
3636 eval {
3637 &main::dumpvar(
3638 $packname,
3639 defined $option{dumpDepth}
3640 ? $option{dumpDepth}
3641 : -1, # assume -1 unless specified
3642 @vars
3643 );
3644 };
3645
3646 # The die doesn't need to include the $@, because
3647 # it will automatically get propagated for us.
3648 if ($@) {
3649 die unless $@ =~ /dumpvar print failed/;
3650 }
3651 } ## end if (defined &main::dumpvar)
3652 else {
3653
3654 # Couldn't load dumpvar.
3655 print $OUT "dumpvar.pl not available.\n";
3656 }
3657
3658 # Restore the output filehandle, and go round again.
3659 select($savout);
3660 next CMD;
3661 }
3662
3663 return;
3664}
3665
d1450c23
SF
3666sub _handle_dash_command {
3667
3668 if ($DB::cmd eq '-') {
3669
3670 # back up by a window; go to 1 if back too far.
3671 $start -= $incr + $window + 1;
3672 $start = 1 if $start <= 0;
3673 $incr = $window - 1;
3674
3675 # Generate and execute a "l +" command (handled below).
3676 $DB::cmd = 'l ' . ($start) . '+';
3677 }
3678 return;
3679}
3680
cb9d1513
SF
3681sub _n_or_s_commands_generic {
3682 my ($self, $new_val) = @_;
73c5e526 3683 # n - next
cb9d1513 3684 next CMD if DB::_DB__is_finished();
73c5e526 3685
cb9d1513
SF
3686 # Single step, but don't enter subs.
3687 $single = $new_val;
3688
3689 # Save for empty command (repeat last).
3690 $laststep = $DB::cmd;
3691 last CMD;
3692}
73c5e526 3693
cb9d1513
SF
3694sub _n_or_s {
3695 my ($self, $letter, $new_val) = @_;
3696
3697 if ($DB::cmd eq $letter) {
3698 $self->_n_or_s_commands_generic($new_val);
73c5e526
SF
3699 }
3700
3701 return;
3702}
3703
cb9d1513
SF
3704sub _handle_n_command {
3705 my $self = shift;
3706
3707 return $self->_n_or_s('n', 2);
3708}
3709
3710sub _handle_s_command {
3711 my $self = shift;
3712
3713 return $self->_n_or_s('s', 1);
3714}
3715
573b5003
SF
3716sub _handle_r_command {
3717 my $self = shift;
3718 # r - return from the current subroutine.
3719 if ($DB::cmd eq 'r') {
3720
3721 # Can't do anything if the program's over.
3722 next CMD if DB::_DB__is_finished();
3723
3724 # Turn on stack trace.
3725 $stack[$stack_depth] |= 1;
3726
3727 # Print return value unless the stack is empty.
3728 $doret = $option{PrintRet} ? $stack_depth - 1 : -2;
3729 last CMD;
3730 }
3731
3732 return;