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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
c7e68384 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
638 $evalarg
639 $filename
640 $frame
641 $hist
642 $histfile
643 $histsize
644 $ImmediateStop
645 $IN
646 $inhibit_exit
647 @ini_INC
648 $ini_warn
649 $line
650 $maxtrace
651 $od
652 $onetimeDump
653 $onetimedumpDepth
654 %option
655 @options
656 $osingle
657 $otrace
658 $OUT
659 $packname
660 $pager
661 $post
662 %postponed
663 $prc
664 $pre
665 $pretype
666 $psh
667 @RememberOnROptions
668 $remoteport
669 @res
670 $rl
671 @saved
672 $signal
673 $signalLevel
674 $single
675 $start
676 $sub
677 %sub
678 $subname
679 $term
680 $trace
681 $usercontext
682 $warnLevel
683 $window
684);
685
686# Used to save @ARGV and extract any debugger-related flags.
687use vars qw(@ARGS);
688
689# Used to prevent multiple entries to diesignal()
690# (if for instance diesignal() itself dies)
691use vars qw($panic);
692
693# Used to prevent the debugger from running nonstop
694# after a restart
695use vars qw($second_time);
696
697sub _calc_usercontext {
698 my ($package) = @_;
699
700 # Cancel strict completely for the evaluated code, so the code
701 # the user evaluates won't be affected by it. (Shlomi Fish)
22fc883d 702 return 'no strict; ($@, $!, $^E, $,, $/, $\, $^W) = @DB::saved;'
6b24a4b7
SF
703 . "package $package;"; # this won't let them modify, alas
704}
705
c1051fcf 706sub eval {
69893cff 707
c1051fcf 708 # 'my' would make it visible from user code
e22ea7cc 709 # but so does local! --tchrist
69893cff 710 # Remember: this localizes @DB::res, not @main::res.
c1051fcf
IZ
711 local @res;
712 {
e22ea7cc
RF
713
714 # Try to keep the user code from messing with us. Save these so that
715 # even if the eval'ed code changes them, we can put them back again.
716 # Needed because the user could refer directly to the debugger's
69893cff
RGS
717 # package globals (and any 'my' variables in this containing scope)
718 # inside the eval(), and we want to try to stay safe.
e22ea7cc 719 local $otrace = $trace;
69893cff
RGS
720 local $osingle = $single;
721 local $od = $^D;
722
723 # Untaint the incoming eval() argument.
724 { ($evalarg) = $evalarg =~ /(.*)/s; }
725
e22ea7cc 726 # $usercontext built in DB::DB near the comment
69893cff
RGS
727 # "set up the context for DB::eval ..."
728 # Evaluate and save any results.
e22ea7cc 729 @res = eval "$usercontext $evalarg;\n"; # '\n' for nice recursive debug
69893cff
RGS
730
731 # Restore those old values.
732 $trace = $otrace;
733 $single = $osingle;
734 $^D = $od;
c1051fcf 735 }
69893cff
RGS
736
737 # Save the current value of $@, and preserve it in the debugger's copy
738 # of the saved precious globals.
c1051fcf 739 my $at = $@;
69893cff
RGS
740
741 # Since we're only saving $@, we only have to localize the array element
742 # that it will be stored in.
e22ea7cc 743 local $saved[0]; # Preserve the old value of $@
7c54f46a 744 eval { DB::save() };
69893cff
RGS
745
746 # Now see whether we need to report an error back to the user.
c1051fcf 747 if ($at) {
69893cff
RGS
748 local $\ = '';
749 print $OUT $at;
750 }
751
752 # Display as required by the caller. $onetimeDump and $onetimedumpDepth
753 # are package globals.
754 elsif ($onetimeDump) {
e22ea7cc
RF
755 if ( $onetimeDump eq 'dump' ) {
756 local $option{dumpDepth} = $onetimedumpDepth
757 if defined $onetimedumpDepth;
758 dumpit( $OUT, \@res );
759 }
760 elsif ( $onetimeDump eq 'methods' ) {
761 methods( $res[0] );
762 }
69893cff 763 } ## end elsif ($onetimeDump)
c1051fcf 764 @res;
69893cff
RGS
765} ## end sub eval
766
767############################################## End lexical danger zone
c1051fcf 768
e22ea7cc
RF
769# After this point it is safe to introduce lexicals.
770# The code being debugged will be executing in its own context, and
69893cff 771# can't see the inside of the debugger.
d338d6fe 772#
e22ea7cc 773# However, one should not overdo it: leave as much control from outside as
69893cff
RGS
774# possible. If you make something a lexical, it's not going to be addressable
775# from outside the debugger even if you know its name.
776
d338d6fe
PP
777# This file is automatically included if you do perl -d.
778# It's probably not useful to include this yourself.
779#
e22ea7cc 780# Before venturing further into these twisty passages, it is
2f7e9187
MS
781# wise to read the perldebguts man page or risk the ire of dragons.
782#
69893cff
RGS
783# (It should be noted that perldebguts will tell you a lot about
784# the underlying mechanics of how the debugger interfaces into the
785# Perl interpreter, but not a lot about the debugger itself. The new
786# comments in this code try to address this problem.)
787
d338d6fe 788# Note that no subroutine call is possible until &DB::sub is defined
36477c24 789# (for subroutines defined outside of the package DB). In fact the same is
d338d6fe 790# true if $deep is not defined.
055fd3a9
GS
791
792# Enhanced by ilya@math.ohio-state.edu (Ilya Zakharevich)
055fd3a9
GS
793
794# modified Perl debugger, to be run from Emacs in perldb-mode
795# Ray Lischner (uunet!mntgfx!lisch) as of 5 Nov 1990
796# Johan Vromans -- upgrade to 4.0 pl 10
797# Ilya Zakharevich -- patches after 5.001 (and some before ;-)
6fae1ad7 798########################################################################
d338d6fe 799
69893cff
RGS
800=head1 DEBUGGER INITIALIZATION
801
802The debugger starts up in phases.
803
804=head2 BASIC SETUP
805
806First, it initializes the environment it wants to run in: turning off
807warnings during its own compilation, defining variables which it will need
808to avoid warnings later, setting itself up to not exit when the program
809terminates, and defaulting to printing return values for the C<r> command.
810
811=cut
812
eda6e075 813# Needed for the statement after exec():
69893cff
RGS
814#
815# This BEGIN block is simply used to switch off warnings during debugger
98dc9551 816# compilation. Probably it would be better practice to fix the warnings,
69893cff 817# but this is how it's done at the moment.
eda6e075 818
e22ea7cc
RF
819BEGIN {
820 $ini_warn = $^W;
821 $^W = 0;
822} # Switch compilation warnings off until another BEGIN.
d12a4851 823
69893cff
RGS
824local ($^W) = 0; # Switch run-time warnings off during init.
825
2cbb2ee1
RGS
826=head2 THREADS SUPPORT
827
828If we are running under a threaded Perl, we require threads and threads::shared
829if the environment variable C<PERL5DB_THREADED> is set, to enable proper
830threaded debugger control. C<-dt> can also be used to set this.
831
832Each new thread will be announced and the debugger prompt will always inform
833you of each new thread created. It will also indicate the thread id in which
834we are currently running within the prompt like this:
835
836 [tid] DB<$i>
837
838Where C<[tid]> is an integer thread id and C<$i> is the familiar debugger
839command prompt. The prompt will show: C<[0]> when running under threads, but
840not actually in a thread. C<[tid]> is consistent with C<gdb> usage.
841
842While running under threads, when you set or delete a breakpoint (etc.), this
b570d64b 843will apply to all threads, not just the currently running one. When you are
2cbb2ee1
RGS
844in a currently executing thread, you will stay there until it completes. With
845the current implementation it is not currently possible to hop from one thread
846to another.
847
848The C<e> and C<E> commands are currently fairly minimal - see C<h e> and C<h E>.
849
850Note that threading support was built into the debugger as of Perl version
851C<5.8.6> and debugger version C<1.2.8>.
852
853=cut
854
855BEGIN {
856 # ensure we can share our non-threaded variables or no-op
857 if ($ENV{PERL5DB_THREADED}) {
858 require threads;
859 require threads::shared;
860 import threads::shared qw(share);
861 $DBGR;
862 share(\$DBGR);
863 lock($DBGR);
864 print "Threads support enabled\n";
865 } else {
866 *lock = sub(*) {};
867 *share = sub(*) {};
868 }
869}
870
2218c045
SF
871# These variables control the execution of 'dumpvar.pl'.
872{
873 package dumpvar;
874 use vars qw(
875 $hashDepth
876 $arrayDepth
877 $dumpDBFiles
878 $dumpPackages
879 $quoteHighBit
880 $printUndef
881 $globPrint
882 $usageOnly
883 );
884}
69893cff 885
2218c045
SF
886# used to control die() reporting in diesignal()
887{
888 package Carp;
889 use vars qw($CarpLevel);
890}
d338d6fe 891
422c59bf 892# without threads, $filename is not defined until DB::DB is called
2cbb2ee1 893foreach my $k (keys (%INC)) {
fb4d8a6c 894 share(\$main::{'_<'.$filename}) if defined $filename;
2cbb2ee1
RGS
895};
896
54d04a52 897# Command-line + PERLLIB:
69893cff 898# Save the contents of @INC before they are modified elsewhere.
54d04a52
IZ
899@ini_INC = @INC;
900
69893cff
RGS
901# This was an attempt to clear out the previous values of various
902# trapped errors. Apparently it didn't help. XXX More info needed!
d338d6fe
PP
903# $prevwarn = $prevdie = $prevbus = $prevsegv = ''; # Does not help?!
904
69893cff
RGS
905# We set these variables to safe values. We don't want to blindly turn
906# off warnings, because other packages may still want them.
e22ea7cc
RF
907$trace = $signal = $single = 0; # Uninitialized warning suppression
908 # (local $^W cannot help - other packages!).
69893cff
RGS
909
910# Default to not exiting when program finishes; print the return
911# value when the 'r' command is used to return from a subroutine.
55497cff 912$inhibit_exit = $option{PrintRet} = 1;
d338d6fe 913
6b24a4b7
SF
914use vars qw($trace_to_depth);
915
5e2b42dd
SF
916# Default to 1E9 so it won't be limited to a certain recursion depth.
917$trace_to_depth = 1E9;
bdba49ad 918
69893cff
RGS
919=head1 OPTION PROCESSING
920
b570d64b
SF
921The debugger's options are actually spread out over the debugger itself and
922C<dumpvar.pl>; some of these are variables to be set, while others are
69893cff
RGS
923subs to be called with a value. To try to make this a little easier to
924manage, the debugger uses a few data structures to define what options
925are legal and how they are to be processed.
926
927First, the C<@options> array defines the I<names> of all the options that
928are to be accepted.
929
930=cut
931
932@options = qw(
5561b870 933 CommandSet HistFile HistSize
e22ea7cc
RF
934 hashDepth arrayDepth dumpDepth
935 DumpDBFiles DumpPackages DumpReused
936 compactDump veryCompact quote
937 HighBit undefPrint globPrint
938 PrintRet UsageOnly frame
939 AutoTrace TTY noTTY
940 ReadLine NonStop LineInfo
941 maxTraceLen recallCommand ShellBang
942 pager tkRunning ornaments
943 signalLevel warnLevel dieLevel
944 inhibit_exit ImmediateStop bareStringify
945 CreateTTY RemotePort windowSize
584420f0 946 DollarCaretP
e22ea7cc 947);
d12a4851 948
584420f0 949@RememberOnROptions = qw(DollarCaretP);
d12a4851 950
69893cff
RGS
951=pod
952
953Second, C<optionVars> lists the variables that each option uses to save its
954state.
955
956=cut
957
6b24a4b7
SF
958use vars qw(%optionVars);
959
69893cff 960%optionVars = (
e22ea7cc
RF
961 hashDepth => \$dumpvar::hashDepth,
962 arrayDepth => \$dumpvar::arrayDepth,
963 CommandSet => \$CommandSet,
964 DumpDBFiles => \$dumpvar::dumpDBFiles,
965 DumpPackages => \$dumpvar::dumpPackages,
966 DumpReused => \$dumpvar::dumpReused,
967 HighBit => \$dumpvar::quoteHighBit,
968 undefPrint => \$dumpvar::printUndef,
969 globPrint => \$dumpvar::globPrint,
970 UsageOnly => \$dumpvar::usageOnly,
971 CreateTTY => \$CreateTTY,
972 bareStringify => \$dumpvar::bareStringify,
973 frame => \$frame,
974 AutoTrace => \$trace,
975 inhibit_exit => \$inhibit_exit,
976 maxTraceLen => \$maxtrace,
977 ImmediateStop => \$ImmediateStop,
978 RemotePort => \$remoteport,
979 windowSize => \$window,
5561b870
AK
980 HistFile => \$histfile,
981 HistSize => \$histsize,
69893cff
RGS
982);
983
984=pod
985
986Third, C<%optionAction> defines the subroutine to be called to process each
987option.
988
b570d64b 989=cut
69893cff 990
6b24a4b7
SF
991use vars qw(%optionAction);
992
69893cff
RGS
993%optionAction = (
994 compactDump => \&dumpvar::compactDump,
995 veryCompact => \&dumpvar::veryCompact,
996 quote => \&dumpvar::quote,
997 TTY => \&TTY,
998 noTTY => \&noTTY,
999 ReadLine => \&ReadLine,
1000 NonStop => \&NonStop,
1001 LineInfo => \&LineInfo,
1002 recallCommand => \&recallCommand,
1003 ShellBang => \&shellBang,
1004 pager => \&pager,
1005 signalLevel => \&signalLevel,
1006 warnLevel => \&warnLevel,
1007 dieLevel => \&dieLevel,
1008 tkRunning => \&tkRunning,
1009 ornaments => \&ornaments,
1010 RemotePort => \&RemotePort,
1011 DollarCaretP => \&DollarCaretP,
d12a4851
JH
1012);
1013
69893cff
RGS
1014=pod
1015
1016Last, the C<%optionRequire> notes modules that must be C<require>d if an
1017option is used.
1018
1019=cut
d338d6fe 1020
69893cff
RGS
1021# Note that this list is not complete: several options not listed here
1022# actually require that dumpvar.pl be loaded for them to work, but are
1023# not in the table. A subsequent patch will correct this problem; for
1024# the moment, we're just recommenting, and we are NOT going to change
1025# function.
6b24a4b7
SF
1026use vars qw(%optionRequire);
1027
eda6e075 1028%optionRequire = (
69893cff
RGS
1029 compactDump => 'dumpvar.pl',
1030 veryCompact => 'dumpvar.pl',
1031 quote => 'dumpvar.pl',
e22ea7cc 1032);
69893cff
RGS
1033
1034=pod
1035
1036There are a number of initialization-related variables which can be set
1037by putting code to set them in a BEGIN block in the C<PERL5DB> environment
1038variable. These are:
1039
1040=over 4
1041
1042=item C<$rl> - readline control XXX needs more explanation
1043
1044=item C<$warnLevel> - whether or not debugger takes over warning handling
1045
1046=item C<$dieLevel> - whether or not debugger takes over die handling
1047
1048=item C<$signalLevel> - whether or not debugger takes over signal handling
1049
1050=item C<$pre> - preprompt actions (array reference)
1051
1052=item C<$post> - postprompt actions (array reference)
1053
1054=item C<$pretype>
1055
1056=item C<$CreateTTY> - whether or not to create a new TTY for this debugger
1057
1058=item C<$CommandSet> - which command set to use (defaults to new, documented set)
1059
1060=back
1061
1062=cut
d338d6fe
PP
1063
1064# These guys may be defined in $ENV{PERL5DB} :
69893cff
RGS
1065$rl = 1 unless defined $rl;
1066$warnLevel = 1 unless defined $warnLevel;
1067$dieLevel = 1 unless defined $dieLevel;
1068$signalLevel = 1 unless defined $signalLevel;
1069$pre = [] unless defined $pre;
1070$post = [] unless defined $post;
1071$pretype = [] unless defined $pretype;
1072$CreateTTY = 3 unless defined $CreateTTY;
1073$CommandSet = '580' unless defined $CommandSet;
1074
2cbb2ee1
RGS
1075share($rl);
1076share($warnLevel);
1077share($dieLevel);
1078share($signalLevel);
1079share($pre);
1080share($post);
1081share($pretype);
1082share($rl);
1083share($CreateTTY);
1084share($CommandSet);
1085
69893cff
RGS
1086=pod
1087
1088The default C<die>, C<warn>, and C<signal> handlers are set up.
1089
1090=cut
055fd3a9 1091
d338d6fe
PP
1092warnLevel($warnLevel);
1093dieLevel($dieLevel);
1094signalLevel($signalLevel);
055fd3a9 1095
69893cff
RGS
1096=pod
1097
1098The pager to be used is needed next. We try to get it from the
5561b870 1099environment first. If it's not defined there, we try to find it in
69893cff
RGS
1100the Perl C<Config.pm>. If it's not there, we default to C<more>. We
1101then call the C<pager()> function to save the pager name.
1102
1103=cut
1104
1105# This routine makes sure $pager is set up so that '|' can use it.
4865a36d 1106pager(
e22ea7cc 1107
69893cff 1108 # If PAGER is defined in the environment, use it.
e22ea7cc
RF
1109 defined $ENV{PAGER}
1110 ? $ENV{PAGER}
69893cff
RGS
1111
1112 # If not, see if Config.pm defines it.
e22ea7cc
RF
1113 : eval { require Config }
1114 && defined $Config::Config{pager}
1115 ? $Config::Config{pager}
69893cff
RGS
1116
1117 # If not, fall back to 'more'.
e22ea7cc
RF
1118 : 'more'
1119 )
1120 unless defined $pager;
69893cff
RGS
1121
1122=pod
1123
1124We set up the command to be used to access the man pages, the command
be9a9b1d
AT
1125recall character (C<!> unless otherwise defined) and the shell escape
1126character (C<!> unless otherwise defined). Yes, these do conflict, and
69893cff
RGS
1127neither works in the debugger at the moment.
1128
1129=cut
1130
055fd3a9 1131setman();
69893cff
RGS
1132
1133# Set up defaults for command recall and shell escape (note:
1134# these currently don't work in linemode debugging).
2218c045
SF
1135recallCommand("!") unless defined $prc;
1136shellBang("!") unless defined $psh;
69893cff
RGS
1137
1138=pod
1139
1140We then set up the gigantic string containing the debugger help.
1141We also set the limit on the number of arguments we'll display during a
1142trace.
1143
1144=cut
1145
04e43a21 1146sethelp();
69893cff
RGS
1147
1148# If we didn't get a default for the length of eval/stack trace args,
1149# set it here.
1d06cb2d 1150$maxtrace = 400 unless defined $maxtrace;
69893cff
RGS
1151
1152=head2 SETTING UP THE DEBUGGER GREETING
1153
be9a9b1d 1154The debugger I<greeting> helps to inform the user how many debuggers are
69893cff
RGS
1155running, and whether the current debugger is the primary or a child.
1156
1157If we are the primary, we just hang onto our pid so we'll have it when
1158or if we start a child debugger. If we are a child, we'll set things up
1159so we'll have a unique greeting and so the parent will give us our own
1160TTY later.
1161
1162We save the current contents of the C<PERLDB_PIDS> environment variable
1163because we mess around with it. We'll also need to hang onto it because
1164we'll need it if we restart.
1165
1166Child debuggers make a label out of the current PID structure recorded in
1167PERLDB_PIDS plus the new PID. They also mark themselves as not having a TTY
1168yet so the parent will give them one later via C<resetterm()>.
1169
1170=cut
1171
e22ea7cc 1172# Save the current contents of the environment; we're about to
69893cff 1173# much with it. We'll need this if we have to restart.
6b24a4b7 1174use vars qw($ini_pids);
f1583d8f 1175$ini_pids = $ENV{PERLDB_PIDS};
69893cff 1176
6b24a4b7
SF
1177use vars qw ($pids $term_pid);
1178
e22ea7cc
RF
1179if ( defined $ENV{PERLDB_PIDS} ) {
1180
69893cff 1181 # We're a child. Make us a label out of the current PID structure
e22ea7cc 1182 # recorded in PERLDB_PIDS plus our (new) PID. Mark us as not having
69893cff 1183 # a term yet so the parent will give us one later via resetterm().
55f4245e
JM
1184
1185 my $env_pids = $ENV{PERLDB_PIDS};
1186 $pids = "[$env_pids]";
1187
1188 # Unless we are on OpenVMS, all programs under the DCL shell run under
1189 # the same PID.
1190
1191 if (($^O eq 'VMS') && ($env_pids =~ /\b$$\b/)) {
1192 $term_pid = $$;
1193 }
1194 else {
1195 $ENV{PERLDB_PIDS} .= "->$$";
1196 $term_pid = -1;
1197 }
1198
69893cff
RGS
1199} ## end if (defined $ENV{PERLDB_PIDS...
1200else {
e22ea7cc
RF
1201
1202 # We're the parent PID. Initialize PERLDB_PID in case we end up with a
69893cff
RGS
1203 # child debugger, and mark us as the parent, so we'll know to set up
1204 # more TTY's is we have to.
1205 $ENV{PERLDB_PIDS} = "$$";
619a0444 1206 $pids = "[pid=$$]";
e22ea7cc 1207 $term_pid = $$;
f1583d8f 1208}
69893cff 1209
6b24a4b7 1210use vars qw($pidprompt);
f1583d8f 1211$pidprompt = '';
69893cff
RGS
1212
1213# Sets up $emacs as a synonym for $slave_editor.
6b24a4b7 1214use vars qw($slave_editor);
69893cff
RGS
1215*emacs = $slave_editor if $slave_editor; # May be used in afterinit()...
1216
1217=head2 READING THE RC FILE
1218
b570d64b 1219The debugger will read a file of initialization options if supplied. If
69893cff
RGS
1220running interactively, this is C<.perldb>; if not, it's C<perldb.ini>.
1221
b570d64b 1222=cut
69893cff
RGS
1223
1224# As noted, this test really doesn't check accurately that the debugger
1225# is running at a terminal or not.
d338d6fe 1226
6b24a4b7 1227use vars qw($rcfile);
fb4d8a6c
SF
1228{
1229 my $dev_tty = (($^O eq 'VMS') ? 'TT:' : '/dev/tty');
1230 # this is the wrong metric!
1231 $rcfile = ((-e $dev_tty) ? ".perldb" : "perldb.ini");
d338d6fe
PP
1232}
1233
69893cff
RGS
1234=pod
1235
1236The debugger does a safety test of the file to be read. It must be owned
1237either by the current user or root, and must only be writable by the owner.
1238
1239=cut
1240
1241# This wraps a safety test around "do" to read and evaluate the init file.
1242#
055fd3a9
GS
1243# This isn't really safe, because there's a race
1244# between checking and opening. The solution is to
1245# open and fstat the handle, but then you have to read and
1246# eval the contents. But then the silly thing gets
69893cff
RGS
1247# your lexical scope, which is unfortunate at best.
1248sub safe_do {
055fd3a9
GS
1249 my $file = shift;
1250
1251 # Just exactly what part of the word "CORE::" don't you understand?
69893cff
RGS
1252 local $SIG{__WARN__};
1253 local $SIG{__DIE__};
055fd3a9 1254
e22ea7cc 1255 unless ( is_safe_file($file) ) {
69893cff 1256 CORE::warn <<EO_GRIPE;
055fd3a9 1257perldb: Must not source insecure rcfile $file.
b570d64b 1258 You or the superuser must be the owner, and it must not
69893cff 1259 be writable by anyone but its owner.
055fd3a9 1260EO_GRIPE
69893cff
RGS
1261 return;
1262 } ## end unless (is_safe_file($file...
055fd3a9
GS
1263
1264 do $file;
1265 CORE::warn("perldb: couldn't parse $file: $@") if $@;
69893cff 1266} ## end sub safe_do
055fd3a9 1267
69893cff
RGS
1268# This is the safety test itself.
1269#
055fd3a9
GS
1270# Verifies that owner is either real user or superuser and that no
1271# one but owner may write to it. This function is of limited use
1272# when called on a path instead of upon a handle, because there are
1273# no guarantees that filename (by dirent) whose file (by ino) is
e22ea7cc 1274# eventually accessed is the same as the one tested.
055fd3a9
GS
1275# Assumes that the file's existence is not in doubt.
1276sub is_safe_file {
1277 my $path = shift;
69893cff 1278 stat($path) || return; # mysteriously vaporized
e22ea7cc 1279 my ( $dev, $ino, $mode, $nlink, $uid, $gid ) = stat(_);
055fd3a9
GS
1280
1281 return 0 if $uid != 0 && $uid != $<;
1282 return 0 if $mode & 022;
1283 return 1;
69893cff 1284} ## end sub is_safe_file
055fd3a9 1285
69893cff 1286# If the rcfile (whichever one we decided was the right one to read)
e22ea7cc
RF
1287# exists, we safely do it.
1288if ( -f $rcfile ) {
055fd3a9 1289 safe_do("./$rcfile");
69893cff 1290}
e22ea7cc 1291
69893cff 1292# If there isn't one here, try the user's home directory.
e22ea7cc 1293elsif ( defined $ENV{HOME} && -f "$ENV{HOME}/$rcfile" ) {
055fd3a9
GS
1294 safe_do("$ENV{HOME}/$rcfile");
1295}
e22ea7cc 1296
69893cff 1297# Else try the login directory.
e22ea7cc 1298elsif ( defined $ENV{LOGDIR} && -f "$ENV{LOGDIR}/$rcfile" ) {
055fd3a9 1299 safe_do("$ENV{LOGDIR}/$rcfile");
d338d6fe
PP
1300}
1301
69893cff 1302# If the PERLDB_OPTS variable has options in it, parse those out next.
e22ea7cc
RF
1303if ( defined $ENV{PERLDB_OPTS} ) {
1304 parse_options( $ENV{PERLDB_OPTS} );
d338d6fe
PP
1305}
1306
69893cff
RGS
1307=pod
1308
1309The last thing we do during initialization is determine which subroutine is
1310to be used to obtain a new terminal when a new debugger is started. Right now,
b0b54b5e 1311the debugger only handles TCP sockets, X11, OS/2, amd Mac OS X
11653f7f 1312(darwin).
69893cff
RGS
1313
1314=cut
1315
1316# Set up the get_fork_TTY subroutine to be aliased to the proper routine.
1317# Works if you're running an xterm or xterm-like window, or you're on
6fae1ad7
RF
1318# OS/2, or on Mac OS X. This may need some expansion.
1319
1320if (not defined &get_fork_TTY) # only if no routine exists
69893cff 1321{
b570d64b 1322 if ( defined $remoteport ) {
11653f7f
JJ
1323 # Expect an inetd-like server
1324 *get_fork_TTY = \&socket_get_fork_TTY; # to listen to us
1325 }
1326 elsif (defined $ENV{TERM} # If we know what kind
6fae1ad7
RF
1327 # of terminal this is,
1328 and $ENV{TERM} eq 'xterm' # and it's an xterm,
1329 and defined $ENV{DISPLAY} # and what display it's on,
1330 )
1331 {
1332 *get_fork_TTY = \&xterm_get_fork_TTY; # use the xterm version
1333 }
1334 elsif ( $^O eq 'os2' ) { # If this is OS/2,
1335 *get_fork_TTY = \&os2_get_fork_TTY; # use the OS/2 version
1336 }
1337 elsif ( $^O eq 'darwin' # If this is Mac OS X
1338 and defined $ENV{TERM_PROGRAM} # and we're running inside
1339 and $ENV{TERM_PROGRAM}
1340 eq 'Apple_Terminal' # Terminal.app
1341 )
1342 {
1343 *get_fork_TTY = \&macosx_get_fork_TTY; # use the Mac OS X version
1344 }
69893cff 1345} ## end if (not defined &get_fork_TTY...
e22ea7cc 1346
dbb46cec
DQ
1347# untaint $^O, which may have been tainted by the last statement.
1348# see bug [perl #24674]
e22ea7cc
RF
1349$^O =~ m/^(.*)\z/;
1350$^O = $1;
f1583d8f 1351
d12a4851 1352# Here begin the unreadable code. It needs fixing.
055fd3a9 1353
69893cff
RGS
1354=head2 RESTART PROCESSING
1355
1356This section handles the restart command. When the C<R> command is invoked, it
1357tries to capture all of the state it can into environment variables, and
1358then sets C<PERLDB_RESTART>. When we start executing again, we check to see
1359if C<PERLDB_RESTART> is there; if so, we reload all the information that
1360the R command stuffed into the environment variables.
1361
b570d64b 1362 PERLDB_RESTART - flag only, contains no restart data itself.
69893cff
RGS
1363 PERLDB_HIST - command history, if it's available
1364 PERLDB_ON_LOAD - breakpoints set by the rc file
1365 PERLDB_POSTPONE - subs that have been loaded/not executed, and have actions
1366 PERLDB_VISITED - files that had breakpoints
1367 PERLDB_FILE_... - breakpoints for a file
1368 PERLDB_OPT - active options
1369 PERLDB_INC - the original @INC
1370 PERLDB_PRETYPE - preprompt debugger actions
1371 PERLDB_PRE - preprompt Perl code
1372 PERLDB_POST - post-prompt Perl code
1373 PERLDB_TYPEAHEAD - typeahead captured by readline()
1374
1375We chug through all these variables and plug the values saved in them
1376back into the appropriate spots in the debugger.
1377
1378=cut
1379
6b24a4b7
SF
1380use vars qw(@hist @truehist %postponed_file @typeahead);
1381
fb0fb5f4
SF
1382sub _restore_shared_globals_after_restart
1383{
1384 @hist = get_list('PERLDB_HIST');
1385 %break_on_load = get_list("PERLDB_ON_LOAD");
1386 %postponed = get_list("PERLDB_POSTPONE");
1387
1388 share(@hist);
1389 share(@truehist);
1390 share(%break_on_load);
1391 share(%postponed);
1392}
1393
e18a02a6 1394sub _restore_breakpoints_and_actions {
e22ea7cc 1395
e22ea7cc 1396 my @had_breakpoints = get_list("PERLDB_VISITED");
e18a02a6 1397
bdba49ad
SF
1398 for my $file_idx ( 0 .. $#had_breakpoints ) {
1399 my $filename = $had_breakpoints[$file_idx];
1400 my %pf = get_list("PERLDB_FILE_$file_idx");
1401 $postponed_file{ $filename } = \%pf if %pf;
1402 my @lines = sort {$a <=> $b} keys(%pf);
1403 my @enabled_statuses = get_list("PERLDB_FILE_ENABLED_$file_idx");
1404 for my $line_idx (0 .. $#lines) {
1405 _set_breakpoint_enabled_status(
1406 $filename,
1407 $lines[$line_idx],
1408 ($enabled_statuses[$line_idx] ? 1 : ''),
1409 );
1410 }
e22ea7cc 1411 }
69893cff 1412
e18a02a6
SF
1413 return;
1414}
1415
ca50076b
SF
1416sub _restore_options_after_restart
1417{
1418 my %options_map = get_list("PERLDB_OPT");
1419
1420 while ( my ( $opt, $val ) = each %options_map ) {
1421 $val =~ s/[\\\']/\\$1/g;
1422 parse_options("$opt'$val'");
1423 }
1424
1425 return;
1426}
1427
18580168
SF
1428sub _restore_globals_after_restart
1429{
1430 # restore original @INC
1431 @INC = get_list("PERLDB_INC");
1432 @ini_INC = @INC;
1433
1434 # return pre/postprompt actions and typeahead buffer
1435 $pretype = [ get_list("PERLDB_PRETYPE") ];
1436 $pre = [ get_list("PERLDB_PRE") ];
1437 $post = [ get_list("PERLDB_POST") ];
1438 @typeahead = get_list( "PERLDB_TYPEAHEAD", @typeahead );
1439
1440 return;
1441}
1442
fb0fb5f4 1443
e18a02a6
SF
1444if ( exists $ENV{PERLDB_RESTART} ) {
1445
1446 # We're restarting, so we don't need the flag that says to restart anymore.
1447 delete $ENV{PERLDB_RESTART};
1448
1449 # $restart = 1;
fb0fb5f4 1450 _restore_shared_globals_after_restart();
e18a02a6
SF
1451
1452 _restore_breakpoints_and_actions();
1453
69893cff 1454 # restore options
ca50076b 1455 _restore_options_after_restart();
69893cff 1456
18580168 1457 _restore_globals_after_restart();
69893cff
RGS
1458} ## end if (exists $ENV{PERLDB_RESTART...
1459
1460=head2 SETTING UP THE TERMINAL
1461
1462Now, we'll decide how the debugger is going to interact with the user.
1463If there's no TTY, we set the debugger to run non-stop; there's not going
1464to be anyone there to enter commands.
1465
1466=cut
54d04a52 1467
6b24a4b7
SF
1468use vars qw($notty $runnonstop $console $tty $LINEINFO);
1469use vars qw($lineinfo $doccmd);
1470
d338d6fe 1471if ($notty) {
69893cff 1472 $runnonstop = 1;
2cbb2ee1 1473 share($runnonstop);
69893cff 1474}
d12a4851 1475
69893cff
RGS
1476=pod
1477
1478If there is a TTY, we have to determine who it belongs to before we can
1479proceed. If this is a slave editor or graphical debugger (denoted by
1480the first command-line switch being '-emacs'), we shift this off and
1481set C<$rl> to 0 (XXX ostensibly to do straight reads).
1482
1483=cut
1484
1485else {
e22ea7cc 1486
69893cff
RGS
1487 # Is Perl being run from a slave editor or graphical debugger?
1488 # If so, don't use readline, and set $slave_editor = 1.
2b0b9dd1
SF
1489 if ($slave_editor = ( @main::ARGV && ( $main::ARGV[0] eq '-emacs' ) )) {
1490 $rl = 0;
1491 shift(@main::ARGV);
1492 }
e22ea7cc
RF
1493
1494 #require Term::ReadLine;
d12a4851 1495
69893cff
RGS
1496=pod
1497
1498We then determine what the console should be on various systems:
1499
1500=over 4
1501
1502=item * Cygwin - We use C<stdin> instead of a separate device.
1503
1504=cut
1505
e22ea7cc
RF
1506 if ( $^O eq 'cygwin' ) {
1507
69893cff
RGS
1508 # /dev/tty is binary. use stdin for textmode
1509 undef $console;
1510 }
1511
1512=item * Unix - use C</dev/tty>.
1513
1514=cut
1515
e22ea7cc 1516 elsif ( -e "/dev/tty" ) {
69893cff
RGS
1517 $console = "/dev/tty";
1518 }
1519
1520=item * Windows or MSDOS - use C<con>.
1521
1522=cut
1523
e22ea7cc 1524 elsif ( $^O eq 'dos' or -e "con" or $^O eq 'MSWin32' ) {
69893cff
RGS
1525 $console = "con";
1526 }
1527
69893cff
RGS
1528=item * VMS - use C<sys$command>.
1529
1530=cut
1531
1532 else {
e22ea7cc 1533
69893cff
RGS
1534 # everything else is ...
1535 $console = "sys\$command";
d12a4851 1536 }
69893cff
RGS
1537
1538=pod
1539
1540=back
1541
1542Several other systems don't use a specific console. We C<undef $console>
1543for those (Windows using a slave editor/graphical debugger, NetWare, OS/2
1544with a slave editor, Epoc).
1545
1546=cut
d12a4851 1547
e22ea7cc
RF
1548 if ( ( $^O eq 'MSWin32' ) and ( $slave_editor or defined $ENV{EMACS} ) ) {
1549
69893cff 1550 # /dev/tty is binary. use stdin for textmode
e22ea7cc
RF
1551 $console = undef;
1552 }
1553
1554 if ( $^O eq 'NetWare' ) {
d12a4851 1555
69893cff
RGS
1556 # /dev/tty is binary. use stdin for textmode
1557 $console = undef;
1558 }
d12a4851 1559
69893cff
RGS
1560 # In OS/2, we need to use STDIN to get textmode too, even though
1561 # it pretty much looks like Unix otherwise.
e22ea7cc
RF
1562 if ( defined $ENV{OS2_SHELL} and ( $slave_editor or $ENV{WINDOWID} ) )
1563 { # In OS/2
1564 $console = undef;
1565 }
1566
1567 # EPOC also falls into the 'got to use STDIN' camp.
1568 if ( $^O eq 'epoc' ) {
1569 $console = undef;
1570 }
d12a4851 1571
69893cff
RGS
1572=pod
1573
1574If there is a TTY hanging around from a parent, we use that as the console.
1575
1576=cut
1577
e22ea7cc 1578 $console = $tty if defined $tty;
d12a4851 1579
b570d64b 1580=head2 SOCKET HANDLING
69893cff
RGS
1581
1582The debugger is capable of opening a socket and carrying out a debugging
1583session over the socket.
1584
1585If C<RemotePort> was defined in the options, the debugger assumes that it
1586should try to start a debugging session on that port. It builds the socket
1587and then tries to connect the input and output filehandles to it.
1588
1589=cut
1590
1591 # Handle socket stuff.
e22ea7cc
RF
1592
1593 if ( defined $remoteport ) {
1594
69893cff
RGS
1595 # If RemotePort was defined in the options, connect input and output
1596 # to the socket.
11653f7f 1597 $IN = $OUT = connect_remoteport();
69893cff
RGS
1598 } ## end if (defined $remoteport)
1599
1600=pod
1601
1602If no C<RemotePort> was defined, and we want to create a TTY on startup,
1603this is probably a situation where multiple debuggers are running (for example,
1604a backticked command that starts up another debugger). We create a new IN and
1605OUT filehandle, and do the necessary mojo to create a new TTY if we know how
1606and if we can.
1607
1608=cut
1609
1610 # Non-socket.
1611 else {
e22ea7cc 1612
69893cff
RGS
1613 # Two debuggers running (probably a system or a backtick that invokes
1614 # the debugger itself under the running one). create a new IN and OUT
e22ea7cc 1615 # filehandle, and do the necessary mojo to create a new tty if we
69893cff 1616 # know how, and we can.
e22ea7cc
RF
1617 create_IN_OUT(4) if $CreateTTY & 4;
1618 if ($console) {
1619
69893cff 1620 # If we have a console, check to see if there are separate ins and
cd1191f1 1621 # outs to open. (They are assumed identical if not.)
69893cff 1622
e22ea7cc
RF
1623 my ( $i, $o ) = split /,/, $console;
1624 $o = $i unless defined $o;
69893cff 1625
69893cff 1626 # read/write on in, or just read, or read on STDIN.
e22ea7cc
RF
1627 open( IN, "+<$i" )
1628 || open( IN, "<$i" )
1629 || open( IN, "<&STDIN" );
1630
69893cff
RGS
1631 # read/write/create/clobber out, or write/create/clobber out,
1632 # or merge with STDERR, or merge with STDOUT.
e22ea7cc
RF
1633 open( OUT, "+>$o" )
1634 || open( OUT, ">$o" )
1635 || open( OUT, ">&STDERR" )
1636 || open( OUT, ">&STDOUT" ); # so we don't dongle stdout
1637
1638 } ## end if ($console)
1639 elsif ( not defined $console ) {
1640
1641 # No console. Open STDIN.
1642 open( IN, "<&STDIN" );
1643
1644 # merge with STDERR, or with STDOUT.
1645 open( OUT, ">&STDERR" )
1646 || open( OUT, ">&STDOUT" ); # so we don't dongle stdout
1647 $console = 'STDIN/OUT';
69893cff
RGS
1648 } ## end elsif (not defined $console)
1649
1650 # Keep copies of the filehandles so that when the pager runs, it
1651 # can close standard input without clobbering ours.
2b0b9dd1
SF
1652 if ($console or (not defined($console))) {
1653 $IN = \*IN;
1654 $OUT = \*OUT;
1655 }
e22ea7cc
RF
1656 } ## end elsif (from if(defined $remoteport))
1657
1658 # Unbuffer DB::OUT. We need to see responses right away.
70c9432b 1659 $OUT->autoflush(1);
e22ea7cc
RF
1660
1661 # Line info goes to debugger output unless pointed elsewhere.
1662 # Pointing elsewhere makes it possible for slave editors to
1663 # keep track of file and position. We have both a filehandle
1664 # and a I/O description to keep track of.
1665 $LINEINFO = $OUT unless defined $LINEINFO;
1666 $lineinfo = $console unless defined $lineinfo;
2cbb2ee1 1667 # share($LINEINFO); # <- unable to share globs
b570d64b 1668 share($lineinfo); #
e22ea7cc 1669
69893cff
RGS
1670=pod
1671
1672To finish initialization, we show the debugger greeting,
1673and then call the C<afterinit()> subroutine if there is one.
1674
1675=cut
d12a4851 1676
e22ea7cc
RF
1677 # Show the debugger greeting.
1678 $header =~ s/.Header: ([^,]+),v(\s+\S+\s+\S+).*$/$1$2/;
1679 unless ($runnonstop) {
1680 local $\ = '';
1681 local $, = '';
1682 if ( $term_pid eq '-1' ) {
1683 print $OUT "\nDaughter DB session started...\n";
1684 }
1685 else {
1686 print $OUT "\nLoading DB routines from $header\n";
1687 print $OUT (
1688 "Editor support ",
1689 $slave_editor ? "enabled" : "available", ".\n"
1690 );
1691 print $OUT
1f874cb6 1692"\nEnter h or 'h h' for help, or '$doccmd perldebug' for more help.\n\n";
69893cff
RGS
1693 } ## end else [ if ($term_pid eq '-1')
1694 } ## end unless ($runnonstop)
1695} ## end else [ if ($notty)
1696
1697# XXX This looks like a bug to me.
1698# Why copy to @ARGS and then futz with @args?
d338d6fe 1699@ARGS = @ARGV;
6b24a4b7 1700# for (@args) {
69893cff
RGS
1701 # Make sure backslashes before single quotes are stripped out, and
1702 # keep args unless they are numeric (XXX why?)
e22ea7cc
RF
1703 # s/\'/\\\'/g; # removed while not justified understandably
1704 # s/(.*)/'$1'/ unless /^-?[\d.]+$/; # ditto
6b24a4b7 1705# }
d338d6fe 1706
e22ea7cc 1707# If there was an afterinit() sub defined, call it. It will get
69893cff 1708# executed in our scope, so it can fiddle with debugger globals.
e22ea7cc 1709if ( defined &afterinit ) { # May be defined in $rcfile
2b0b9dd1 1710 afterinit();
d338d6fe 1711}
e22ea7cc 1712
69893cff 1713# Inform us about "Stack dump during die enabled ..." in dieLevel().
6b24a4b7
SF
1714use vars qw($I_m_init);
1715
43aed9ee
IZ
1716$I_m_init = 1;
1717
d338d6fe
PP
1718############################################################ Subroutines
1719
69893cff
RGS
1720=head1 SUBROUTINES
1721
1722=head2 DB
1723
1724This gigantic subroutine is the heart of the debugger. Called before every
1725statement, its job is to determine if a breakpoint has been reached, and
1726stop if so; read commands from the user, parse them, and execute
b468dcb6 1727them, and then send execution off to the next statement.
69893cff
RGS
1728
1729Note that the order in which the commands are processed is very important;
1730some commands earlier in the loop will actually alter the C<$cmd> variable
be9a9b1d 1731to create other commands to be executed later. This is all highly I<optimized>
69893cff
RGS
1732but can be confusing. Check the comments for each C<$cmd ... && do {}> to
1733see what's happening in any given command.
1734
1735=cut
1736
6b24a4b7
SF
1737use vars qw(
1738 $action
1739 %alias
1740 $cmd
1741 $doret
1742 $fall_off_end
1743 $file
1744 $filename_ini
1745 $finished
1746 %had_breakpoints
1747 $incr
1748 $laststep
1749 $level
1750 $max
1751 @old_watch
1752 $package
1753 $rc
1754 $sh
1755 @stack
1756 $stack_depth
1757 @to_watch
1758 $try
2c247e84 1759 $end
6b24a4b7
SF
1760);
1761
6791e41b
SF
1762sub _DB__determine_if_we_should_break
1763{
1764 # if we have something here, see if we should break.
1765 # $stop is lexical and local to this block - $action on the other hand
1766 # is global.
1767 my $stop;
1768
1769 if ( $dbline{$line}
1770 && _is_breakpoint_enabled($filename, $line)
1771 && (( $stop, $action ) = split( /\0/, $dbline{$line} ) ) )
1772 {
1773
1774 # Stop if the stop criterion says to just stop.
1775 if ( $stop eq '1' ) {
1776 $signal |= 1;
1777 }
1778
1779 # It's a conditional stop; eval it in the user's context and
1780 # see if we should stop. If so, remove the one-time sigil.
1781 elsif ($stop) {
1782 $evalarg = "\$DB::signal |= 1 if do {$stop}";
1783 &eval;
1784 # If the breakpoint is temporary, then delete its enabled status.
1785 if ($dbline{$line} =~ s/;9($|\0)/$1/) {
1786 _cancel_breakpoint_temp_enabled_status($filename, $line);
1787 }
1788 }
1789 } ## end if ($dbline{$line} && ...
1790}
1791
2b0b9dd1
SF
1792sub DB {
1793
1794 # lock the debugger and get the thread id for the prompt
1795 lock($DBGR);
1796 my $tid;
1797 my $position;
1798 my ($prefix, $after, $infix);
1799 my $pat;
22fc883d 1800 my $explicit_stop;
2b0b9dd1
SF
1801
1802 if ($ENV{PERL5DB_THREADED}) {
1803 $tid = eval { "[".threads->tid."]" };
1804 }
1805
22fc883d
SF
1806 my $obj = DB::Obj->new(
1807 {
1808 position => \$position,
1809 prefix => \$prefix,
1810 after => \$after,
1811 explicit_stop => \$explicit_stop,
1812 infix => \$infix,
1813 },
1814 );
1815
1816 $obj->_DB_on_init__initialize_globals(@_);
2b0b9dd1 1817
69893cff
RGS
1818 # Preserve current values of $@, $!, $^E, $,, $/, $\, $^W.
1819 # The code being debugged may have altered them.
d338d6fe 1820 &save;
69893cff
RGS
1821
1822 # Since DB::DB gets called after every line, we can use caller() to
1823 # figure out where we last were executing. Sneaky, eh? This works because
e22ea7cc 1824 # caller is returning all the extra information when called from the
69893cff 1825 # debugger.
e22ea7cc 1826 local ( $package, $filename, $line ) = caller;
6b24a4b7 1827 $filename_ini = $filename;
69893cff
RGS
1828
1829 # set up the context for DB::eval, so it can properly execute
1830 # code on behalf of the user. We add the package in so that the
1831 # code is eval'ed in the proper package (not in the debugger!).
6b24a4b7 1832 local $usercontext = _calc_usercontext($package);
69893cff
RGS
1833
1834 # Create an alias to the active file magical array to simplify
1835 # the code here.
e22ea7cc 1836 local (*dbline) = $main::{ '_<' . $filename };
aa057b67 1837
69893cff 1838 # Last line in the program.
55783941 1839 $max = $#dbline;
69893cff 1840
22fc883d 1841 _DB__determine_if_we_should_break(@_);
69893cff
RGS
1842
1843 # Preserve the current stop-or-not, and see if any of the W
1844 # (watch expressions) has changed.
36477c24 1845 my $was_signal = $signal;
69893cff
RGS
1846
1847 # If we have any watch expressions ...
22fc883d 1848 $obj->_DB__handle_watch_expressions(@_);
69893cff
RGS
1849
1850=head2 C<watchfunction()>
1851
1852C<watchfunction()> is a function that can be defined by the user; it is a
b570d64b 1853function which will be run on each entry to C<DB::DB>; it gets the
69893cff
RGS
1854current package, filename, and line as its parameters.
1855
b570d64b 1856The watchfunction can do anything it likes; it is executing in the
69893cff
RGS
1857debugger's context, so it has access to all of the debugger's internal
1858data structures and functions.
1859
1860C<watchfunction()> can control the debugger's actions. Any of the following
1861will cause the debugger to return control to the user's program after
1862C<watchfunction()> executes:
1863
b570d64b 1864=over 4
69893cff 1865
be9a9b1d
AT
1866=item *
1867
1868Returning a false value from the C<watchfunction()> itself.
1869
1870=item *
1871
1872Altering C<$single> to a false value.
1873
1874=item *
69893cff 1875
be9a9b1d 1876Altering C<$signal> to a false value.
69893cff 1877
be9a9b1d 1878=item *
69893cff 1879
be9a9b1d 1880Turning off the C<4> bit in C<$trace> (this also disables the
69893cff
RGS
1881check for C<watchfunction()>. This can be done with
1882
1883 $trace &= ~4;
1884
1885=back
1886
1887=cut
1888
e22ea7cc 1889 # If there's a user-defined DB::watchfunction, call it with the
69893cff
RGS
1890 # current package, filename, and line. The function executes in
1891 # the DB:: package.
e22ea7cc
RF
1892 if ( $trace & 4 ) { # User-installed watch
1893 return
1894 if watchfunction( $package, $filename, $line )
1895 and not $single
1896 and not $was_signal
1897 and not( $trace & ~4 );
69893cff
RGS
1898 } ## end if ($trace & 4)
1899
e22ea7cc 1900 # Pick up any alteration to $signal in the watchfunction, and
69893cff 1901 # turn off the signal now.
6027b9a3 1902 $was_signal = $signal;
69893cff
RGS
1903 $signal = 0;
1904
1905=head2 GETTING READY TO EXECUTE COMMANDS
1906
1907The debugger decides to take control if single-step mode is on, the
1908C<t> command was entered, or the user generated a signal. If the program
1909has fallen off the end, we set things up so that entering further commands
1910won't cause trouble, and we say that the program is over.
1911
1912=cut
1913
8dc67a69
SF
1914 # Make sure that we always print if asked for explicitly regardless
1915 # of $trace_to_depth .
22fc883d 1916 $explicit_stop = ($single || $was_signal);
8dc67a69 1917
69893cff
RGS
1918 # Check to see if we should grab control ($single true,
1919 # trace set appropriately, or we got a signal).
8dc67a69 1920 if ( $explicit_stop || ( $trace & 1 ) ) {
22fc883d 1921 $obj->_DB__grab_control(@_);
69893cff
RGS
1922 } ## end if ($single || ($trace...
1923
1924=pod
1925
1926If there's an action to be executed for the line we stopped at, execute it.
b570d64b 1927If there are any preprompt actions, execute those as well.
e219e2fb
RF
1928
1929=cut
1930
69893cff 1931 # If there's an action, do it now.
05da04df
SF
1932 if ($action) {
1933 $evalarg = $action;
1934 DB::eval();
1935 }
e219e2fb 1936
69893cff
RGS
1937 # Are we nested another level (e.g., did we evaluate a function
1938 # that had a breakpoint in it at the debugger prompt)?
e22ea7cc
RF
1939 if ( $single || $was_signal ) {
1940
69893cff 1941 # Yes, go down a level.
e22ea7cc 1942 local $level = $level + 1;
69893cff
RGS
1943
1944 # Do any pre-prompt actions.
e22ea7cc 1945 foreach $evalarg (@$pre) {
7c54f46a 1946 DB::eval();
e22ea7cc 1947 }
69893cff
RGS
1948
1949 # Complain about too much recursion if we passed the limit.
05da04df
SF
1950 if ($single & 4) {
1951 print $OUT $stack_depth . " levels deep in subroutine calls!\n";
1952 }
69893cff
RGS
1953
1954 # The line we're currently on. Set $incr to -1 to stay here
1955 # until we get a command that tells us to advance.
e22ea7cc
RF
1956 $start = $line;
1957 $incr = -1; # for backward motion.
69893cff
RGS
1958
1959 # Tack preprompt debugger actions ahead of any actual input.
e22ea7cc 1960 @typeahead = ( @$pretype, @typeahead );
69893cff
RGS
1961
1962=head2 WHERE ARE WE?
1963
1964XXX Relocate this section?
1965
1966The debugger normally shows the line corresponding to the current line of
1967execution. Sometimes, though, we want to see the next line, or to move elsewhere
1968in the file. This is done via the C<$incr>, C<$start>, and C<$max> variables.
1969
be9a9b1d
AT
1970C<$incr> controls by how many lines the I<current> line should move forward
1971after a command is executed. If set to -1, this indicates that the I<current>
69893cff
RGS
1972line shouldn't change.
1973
be9a9b1d 1974C<$start> is the I<current> line. It is used for things like knowing where to
69893cff
RGS
1975move forwards or backwards from when doing an C<L> or C<-> command.
1976
1977C<$max> tells the debugger where the last line of the current file is. It's
1978used to terminate loops most often.
1979
1980=head2 THE COMMAND LOOP
1981
1982Most of C<DB::DB> is actually a command parsing and dispatch loop. It comes
1983in two parts:
1984
1985=over 4
1986
be9a9b1d
AT
1987=item *
1988
1989The outer part of the loop, starting at the C<CMD> label. This loop
69893cff
RGS
1990reads a command and then executes it.
1991
be9a9b1d
AT
1992=item *
1993
1994The inner part of the loop, starting at the C<PIPE> label. This part
69893cff
RGS
1995is wholly contained inside the C<CMD> block and only executes a command.
1996Used to handle commands running inside a pager.
1997
1998=back
1999
2000So why have two labels to restart the loop? Because sometimes, it's easier to
2001have a command I<generate> another command and then re-execute the loop to do
2002the new command. This is faster, but perhaps a bit more convoluted.
2003
2004=cut
2005
2006 # The big command dispatch loop. It keeps running until the
2007 # user yields up control again.
2008 #
2009 # If we have a terminal for input, and we get something back
2010 # from readline(), keep on processing.
6b24a4b7
SF
2011 my $piped;
2012 my $selected;
2013
e22ea7cc
RF
2014 CMD:
2015 while (
2016
69893cff 2017 # We have a terminal, or can get one ...
e22ea7cc
RF
2018 ( $term || &setterm ),
2019
69893cff 2020 # ... and it belogs to this PID or we get one for this PID ...
e22ea7cc
RF
2021 ( $term_pid == $$ or resetterm(1) ),
2022
69893cff 2023 # ... and we got a line of command input ...
e22ea7cc
RF
2024 defined(
2025 $cmd = &readline(
2cbb2ee1 2026 "$pidprompt $tid DB"
e22ea7cc
RF
2027 . ( '<' x $level )
2028 . ( $#hist + 1 )
2029 . ( '>' x $level ) . " "
69893cff
RGS
2030 )
2031 )
2032 )
2033 {
e22ea7cc 2034
2cbb2ee1 2035 share($cmd);
69893cff
RGS
2036 # ... try to execute the input as debugger commands.
2037
2038 # Don't stop running.
2039 $single = 0;
2040
2041 # No signal is active.
2042 $signal = 0;
2043
2044 # Handle continued commands (ending with \):
3d7a2a93 2045 if ($cmd =~ s/\\\z/\n/) {
e22ea7cc
RF
2046 $cmd .= &readline(" cont: ");
2047 redo CMD;
3d7a2a93 2048 }
69893cff
RGS
2049
2050=head4 The null command
2051
be9a9b1d 2052A newline entered by itself means I<re-execute the last command>. We grab the
69893cff
RGS
2053command out of C<$laststep> (where it was recorded previously), and copy it
2054back into C<$cmd> to be executed below. If there wasn't any previous command,
2055we'll do nothing below (no command will match). If there was, we also save it
2056in the command history and fall through to allow the command parsing to pick
2057it up.
2058
2059=cut
2060
2061 # Empty input means repeat the last command.
e22ea7cc
RF
2062 $cmd =~ /^$/ && ( $cmd = $laststep );
2063 chomp($cmd); # get rid of the annoying extra newline
2064 push( @hist, $cmd ) if length($cmd) > 1;
2065 push( @truehist, $cmd );
2cbb2ee1
RGS
2066 share(@hist);
2067 share(@truehist);
e22ea7cc
RF
2068
2069 # This is a restart point for commands that didn't arrive
2070 # via direct user input. It allows us to 'redo PIPE' to
2071 # re-execute command processing without reading a new command.
69893cff 2072 PIPE: {
e22ea7cc
RF
2073 $cmd =~ s/^\s+//s; # trim annoying leading whitespace
2074 $cmd =~ s/\s+$//s; # trim annoying trailing whitespace
6b24a4b7 2075 my ($i) = split( /\s+/, $cmd );
69893cff
RGS
2076
2077=head3 COMMAND ALIASES
2078
2079The debugger can create aliases for commands (these are stored in the
2080C<%alias> hash). Before a command is executed, the command loop looks it up
2081in the alias hash and substitutes the contents of the alias for the command,
2082completely replacing it.
2083
2084=cut
2085
2086 # See if there's an alias for the command, and set it up if so.
e22ea7cc
RF
2087 if ( $alias{$i} ) {
2088
69893cff
RGS
2089 # Squelch signal handling; we want to keep control here
2090 # if something goes loco during the alias eval.
2091 local $SIG{__DIE__};
2092 local $SIG{__WARN__};
2093
2094 # This is a command, so we eval it in the DEBUGGER's
2095 # scope! Otherwise, we can't see the special debugger
2096 # variables, or get to the debugger's subs. (Well, we
2097 # _could_, but why make it even more complicated?)
2098 eval "\$cmd =~ $alias{$i}";
2099 if ($@) {
2100 local $\ = '';
1f874cb6 2101 print $OUT "Couldn't evaluate '$i' alias: $@";
69893cff
RGS
2102 next CMD;
2103 }
2104 } ## end if ($alias{$i})
2105
2106=head3 MAIN-LINE COMMANDS
2107
2108All of these commands work up to and after the program being debugged has
b570d64b 2109terminated.
69893cff
RGS
2110
2111=head4 C<q> - quit
2112
b570d64b 2113Quit the debugger. This entails setting the C<$fall_off_end> flag, so we don't
69893cff
RGS
2114try to execute further, cleaning any restart-related stuff out of the
2115environment, and executing with the last value of C<$?>.
2116
2117=cut
2118
3d7a2a93 2119 if ($cmd eq 'q') {
69893cff
RGS
2120 $fall_off_end = 1;
2121 clean_ENV();
2122 exit $?;
3d7a2a93 2123 }
69893cff 2124
611272bb 2125=head4 C<t> - trace [n]
69893cff
RGS
2126
2127Turn tracing on or off. Inverts the appropriate bit in C<$trace> (q.v.).
611272bb 2128If level is specified, set C<$trace_to_depth>.
69893cff
RGS
2129
2130=cut
2131
3d7a2a93 2132 if (my ($levels) = $cmd =~ /\At(?:\s+(\d+))?\z/) {
e22ea7cc
RF
2133 $trace ^= 1;
2134 local $\ = '';
611272bb 2135 $trace_to_depth = $levels ? $stack_depth + $levels : 1E9;
e22ea7cc 2136 print $OUT "Trace = "
611272bb
PS
2137 . ( ( $trace & 1 )
2138 ? ( $levels ? "on (to level $trace_to_depth)" : "on" )
2139 : "off" ) . "\n";
e22ea7cc 2140 next CMD;
3d7a2a93 2141 }
69893cff
RGS
2142
2143=head4 C<S> - list subroutines matching/not matching a pattern
2144
2145Walks through C<%sub>, checking to see whether or not to print the name.
2146
2147=cut
2148
826b9a2e
SF
2149 if (my ($print_all_subs, $should_reverse, $Spatt)
2150 = $cmd =~ /\AS(\s+(!)?(.+))?\z/) {
2151 # $Spatt is the pattern (if any) to use.
2152 # Reverse scan?
2153 my $Srev = defined $should_reverse;
2154 # No args - print all subs.
2155 my $Snocheck = !defined $print_all_subs;
69893cff
RGS
2156
2157 # Need to make these sane here.
e22ea7cc
RF
2158 local $\ = '';
2159 local $, = '';
69893cff
RGS
2160
2161 # Search through the debugger's magical hash of subs.
2162 # If $nocheck is true, just print the sub name.
2163 # Otherwise, check it against the pattern. We then use
2164 # the XOR trick to reverse the condition as required.
e22ea7cc
RF
2165 foreach $subname ( sort( keys %sub ) ) {
2166 if ( $Snocheck or $Srev ^ ( $subname =~ /$Spatt/ ) ) {
2167 print $OUT $subname, "\n";
2168 }
2169 }
2170 next CMD;
826b9a2e 2171 }
69893cff
RGS
2172
2173=head4 C<X> - list variables in current package
2174
b570d64b 2175Since the C<V> command actually processes this, just change this to the
69893cff
RGS
2176appropriate C<V> command and fall through.
2177
2178=cut
2179
e22ea7cc 2180 $cmd =~ s/^X\b/V $package/;
69893cff
RGS
2181
2182=head4 C<V> - list variables
2183
b570d64b 2184Uses C<dumpvar.pl> to dump out the current values for selected variables.
69893cff
RGS
2185
2186=cut
2187
2188 # Bare V commands get the currently-being-debugged package
2189 # added.
826b9a2e 2190 if ($cmd eq "V") {
e22ea7cc 2191 $cmd = "V $package";
826b9a2e 2192 }
69893cff
RGS
2193
2194 # V - show variables in package.
826b9a2e
SF
2195 if (my ($new_packname, $new_vars_str) =
2196 $cmd =~ /\AV\b\s*(\S+)\s*(.*)/) {
e22ea7cc 2197
69893cff
RGS
2198 # Save the currently selected filehandle and
2199 # force output to debugger's filehandle (dumpvar
2200 # just does "print" for output).
6b24a4b7 2201 my $savout = select($OUT);
69893cff
RGS
2202
2203 # Grab package name and variables to dump.
826b9a2e
SF
2204 $packname = $new_packname;
2205 my @vars = split( ' ', $new_vars_str );
69893cff
RGS
2206
2207 # If main::dumpvar isn't here, get it.
e81465be 2208 do 'dumpvar.pl' || die $@ unless defined &main::dumpvar;
e22ea7cc
RF
2209 if ( defined &main::dumpvar ) {
2210
69893cff
RGS
2211 # We got it. Turn off subroutine entry/exit messages
2212 # for the moment, along with return values.
e22ea7cc
RF
2213 local $frame = 0;
2214 local $doret = -2;
69893cff
RGS
2215
2216 # must detect sigpipe failures - not catching
2217 # then will cause the debugger to die.
2218 eval {
2219 &main::dumpvar(
2220 $packname,
2221 defined $option{dumpDepth}
e22ea7cc
RF
2222 ? $option{dumpDepth}
2223 : -1, # assume -1 unless specified
69893cff 2224 @vars
e22ea7cc
RF
2225 );
2226 };
2227
2228 # The die doesn't need to include the $@, because
2229 # it will automatically get propagated for us.
2230 if ($@) {
2231 die unless $@ =~ /dumpvar print failed/;
2232 }
2233 } ## end if (defined &main::dumpvar)
2234 else {
2235
2236 # Couldn't load dumpvar.
2237 print $OUT "dumpvar.pl not available.\n";
2238 }
69893cff 2239
69893cff 2240 # Restore the output filehandle, and go round again.
e22ea7cc
RF
2241 select($savout);
2242 next CMD;
826b9a2e 2243 }
69893cff
RGS
2244
2245=head4 C<x> - evaluate and print an expression
2246
2247Hands the expression off to C<DB::eval>, setting it up to print the value
2248via C<dumpvar.pl> instead of just printing it directly.
2249
2250=cut
2251
826b9a2e 2252 if ($cmd =~ s#\Ax\b# #) { # Remainder gets done by DB::eval()
e22ea7cc 2253 $onetimeDump = 'dump'; # main::dumpvar shows the output
69893cff
RGS
2254
2255 # handle special "x 3 blah" syntax XXX propagate
2256 # doc back to special variables.
826b9a2e 2257 if ( $cmd =~ s#\A\s*(\d+)(?=\s)# #) {
e22ea7cc
RF
2258 $onetimedumpDepth = $1;
2259 }
826b9a2e 2260 }
69893cff
RGS
2261
2262=head4 C<m> - print methods
2263
2264Just uses C<DB::methods> to determine what methods are available.
2265
2266=cut
2267
826b9a2e 2268 if ($cmd =~ s#\Am\s+([\w:]+)\s*\z# #) {
e22ea7cc
RF
2269 methods($1);
2270 next CMD;
826b9a2e 2271 }
69893cff
RGS
2272
2273 # m expr - set up DB::eval to do the work
826b9a2e 2274 if ($cmd =~ s#\Am\b# #) { # Rest gets done by DB::eval()
e22ea7cc 2275 $onetimeDump = 'methods'; # method output gets used there
826b9a2e 2276 }
69893cff
RGS
2277
2278=head4 C<f> - switch files
2279
2280=cut
2281
826b9a2e 2282 if (($file) = $cmd =~ /\Af\b\s*(.*)/) {
e22ea7cc 2283 $file =~ s/\s+$//;
69893cff
RGS
2284
2285 # help for no arguments (old-style was return from sub).
e22ea7cc
RF
2286 if ( !$file ) {
2287 print $OUT
2288 "The old f command is now the r command.\n"; # hint
2289 print $OUT "The new f command switches filenames.\n";
2290 next CMD;
2291 } ## end if (!$file)
69893cff
RGS
2292
2293 # if not in magic file list, try a close match.
e22ea7cc
RF
2294 if ( !defined $main::{ '_<' . $file } ) {
2295 if ( ($try) = grep( m#^_<.*$file#, keys %main:: ) ) {
2296 {
2297 $try = substr( $try, 2 );
1f874cb6 2298 print $OUT "Choosing $try matching '$file':\n";
e22ea7cc
RF
2299 $file = $try;
2300 }
2301 } ## end if (($try) = grep(m#^_<.*$file#...
2302 } ## end if (!defined $main::{ ...
69893cff
RGS
2303
2304 # If not successfully switched now, we failed.
e22ea7cc 2305 if ( !defined $main::{ '_<' . $file } ) {
1f874cb6 2306 print $OUT "No file matching '$file' is loaded.\n";
e22ea7cc
RF
2307 next CMD;
2308 }
69893cff 2309
e22ea7cc
RF
2310 # We switched, so switch the debugger internals around.
2311 elsif ( $file ne $filename ) {
2312 *dbline = $main::{ '_<' . $file };
2313 $max = $#dbline;
2314 $filename = $file;
2315 $start = 1;
2316 $cmd = "l";
2317 } ## end elsif ($file ne $filename)
2318
2319 # We didn't switch; say we didn't.
2320 else {
2321 print $OUT "Already in $file.\n";
2322 next CMD;
2323 }
826b9a2e 2324 }
69893cff
RGS
2325
2326=head4 C<.> - return to last-executed line.
2327
2328We set C<$incr> to -1 to indicate that the debugger shouldn't move ahead,
2329and then we look up the line in the magical C<%dbline> hash.
2330
2331=cut
2332
2333 # . command.
826b9a2e 2334 if ($cmd eq '.') {
e22ea7cc 2335 $incr = -1; # stay at current line
69893cff
RGS
2336
2337 # Reset everything to the old location.
e22ea7cc
RF
2338 $start = $line;
2339 $filename = $filename_ini;
2340 *dbline = $main::{ '_<' . $filename };
2341 $max = $#dbline;
69893cff
RGS
2342
2343 # Now where are we?
e22ea7cc
RF
2344 print_lineinfo($position);
2345 next CMD;
826b9a2e 2346 }
69893cff
RGS
2347
2348=head4 C<-> - back one window
2349
2350We change C<$start> to be one window back; if we go back past the first line,
2351we set it to be the first line. We ser C<$incr> to put us back at the
2352currently-executing line, and then put a C<l $start +> (list one window from
2353C<$start>) in C<$cmd> to be executed later.
2354
2355=cut
2356
2357 # - - back a window.
826b9a2e 2358 if ($cmd eq '-') {
e22ea7cc 2359
69893cff 2360 # back up by a window; go to 1 if back too far.
e22ea7cc
RF
2361 $start -= $incr + $window + 1;
2362 $start = 1 if $start <= 0;
2363 $incr = $window - 1;
69893cff
RGS
2364
2365 # Generate and execute a "l +" command (handled below).
e22ea7cc 2366 $cmd = 'l ' . ($start) . '+';
826b9a2e 2367 }
69893cff
RGS
2368
2369=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>, {, {{>
2370
2371In Perl 5.8.0, a realignment of the commands was done to fix up a number of
2372problems, most notably that the default case of several commands destroying
2373the user's work in setting watchpoints, actions, etc. We wanted, however, to
2374retain the old commands for those who were used to using them or who preferred
2375them. At this point, we check for the new commands and call C<cmd_wrapper> to
2376deal with them instead of processing them in-line.
2377
2378=cut
2379
2380 # All of these commands were remapped in perl 5.8.0;
e22ea7cc 2381 # we send them off to the secondary dispatcher (see below).
826b9a2e
SF
2382 if (my ($cmd_letter, $my_arg) = $cmd =~ /\A([aAbBeEhilLMoOPvwW]\b|[<>\{]{1,2})\s*(.*)/so) {
2383 &cmd_wrapper( $cmd_letter, $my_arg, $line );
e22ea7cc 2384 next CMD;
826b9a2e 2385 }
69893cff
RGS
2386
2387=head4 C<y> - List lexicals in higher scope
2388
826b9a2e 2389Uses C<PadWalker> to find the lexicals supplied as arguments in a scope
69893cff
RGS
2390above the current one and then displays then using C<dumpvar.pl>.
2391
2392=cut
2393
826b9a2e
SF
2394 if (my ($match_level, $match_vars)
2395 = $cmd =~ /^y(?:\s+(\d*)\s*(.*))?$/) {
69893cff
RGS
2396
2397 # See if we've got the necessary support.
2398 eval { require PadWalker; PadWalker->VERSION(0.08) }
2399 or &warn(
2400 $@ =~ /locate/
2401 ? "PadWalker module not found - please install\n"
2402 : $@
2403 )
2404 and next CMD;
2405
2406 # Load up dumpvar if we don't have it. If we can, that is.
e81465be 2407 do 'dumpvar.pl' || die $@ unless defined &main::dumpvar;
69893cff
RGS
2408 defined &main::dumpvar
2409 or print $OUT "dumpvar.pl not available.\n"
2410 and next CMD;
2411
2412 # Got all the modules we need. Find them and print them.
826b9a2e 2413 my @vars = split( ' ', $match_vars || '' );
69893cff
RGS
2414
2415 # Find the pad.
826b9a2e 2416 my $h = eval { PadWalker::peek_my( ( $match_level || 0 ) + 1 ) };
69893cff
RGS
2417
2418 # Oops. Can't find it.
2419 $@ and $@ =~ s/ at .*//, &warn($@), next CMD;
2420
2421 # Show the desired vars with dumplex().
2422 my $savout = select($OUT);
2423
2424 # Have dumplex dump the lexicals.
e22ea7cc 2425 dumpvar::dumplex( $_, $h->{$_},
69893cff 2426 defined $option{dumpDepth} ? $option{dumpDepth} : -1,
e22ea7cc
RF
2427 @vars )
2428 for sort keys %$h;
69893cff
RGS
2429 select($savout);
2430 next CMD;
826b9a2e 2431 }
69893cff
RGS
2432
2433=head3 COMMANDS NOT WORKING AFTER PROGRAM ENDS
2434
2435All of the commands below this point don't work after the program being
2436debugged has ended. All of them check to see if the program has ended; this
2437allows the commands to be relocated without worrying about a 'line of
2438demarcation' above which commands can be entered anytime, and below which
2439they can't.
2440
2441=head4 C<n> - single step, but don't trace down into subs
2442
2443Done by setting C<$single> to 2, which forces subs to execute straight through
be9a9b1d 2444when entered (see C<DB::sub>). We also save the C<n> command in C<$laststep>,
826b9a2e 2445so a null command knows what to re-execute.
69893cff
RGS
2446
2447=cut
2448
e22ea7cc 2449 # n - next
826b9a2e 2450 if ($cmd eq 'n') {
44909c61
SF
2451 if ($finished and $level <= 1) {
2452 end_report();
2453 next CMD;
2454 }
e22ea7cc 2455
69893cff
RGS
2456 # Single step, but don't enter subs.
2457 $single = 2;
e22ea7cc 2458
69893cff 2459 # Save for empty command (repeat last).
e22ea7cc
RF
2460 $laststep = $cmd;
2461 last CMD;
826b9a2e 2462 }
69893cff
RGS
2463
2464=head4 C<s> - single-step, entering subs
2465
826b9a2e 2466Sets C<$single> to 1, which causes C<DB::sub> to continue tracing inside
69893cff
RGS
2467subs. Also saves C<s> as C<$lastcmd>.
2468
2469=cut
2470
2471 # s - single step.
826b9a2e 2472 if ($cmd eq 's') {
e22ea7cc 2473
69893cff
RGS
2474 # Get out and restart the command loop if program
2475 # has finished.
1750bb2a
SF
2476 if ($finished and $level <= 1) {
2477 end_report();
2478 next CMD;
2479 }
e22ea7cc 2480
69893cff 2481 # Single step should enter subs.
e22ea7cc
RF
2482 $single = 1;
2483
69893cff 2484 # Save for empty command (repeat last).
e22ea7cc
RF
2485 $laststep = $cmd;
2486 last CMD;
826b9a2e 2487 }
69893cff
RGS
2488
2489=head4 C<c> - run continuously, setting an optional breakpoint
2490
2491Most of the code for this command is taken up with locating the optional
2492breakpoint, which is either a subroutine name or a line number. We set
2493the appropriate one-time-break in C<@dbline> and then turn off single-stepping
2494in this and all call levels above this one.
2495
2496=cut
2497
2498 # c - start continuous execution.
ef18ae63 2499 if (($i) = $cmd =~ m#\Ac\b\s*([\w:]*)\s*\z#) {
e22ea7cc 2500
69893cff
RGS
2501 # Hey, show's over. The debugged program finished
2502 # executing already.
1750bb2a
SF
2503 if ($finished and $level <= 1) {
2504 end_report();
2505 next CMD;
2506 }
69893cff
RGS
2507
2508 # Capture the place to put a one-time break.
ef18ae63 2509 $subname = $i;
69893cff 2510
e22ea7cc
RF
2511 # Probably not needed, since we finish an interactive
2512 # sub-session anyway...
2513 # local $filename = $filename;
2514 # local *dbline = *dbline; # XXX Would this work?!
69893cff
RGS
2515 #
2516 # The above question wonders if localizing the alias
2517 # to the magic array works or not. Since it's commented
2518 # out, we'll just leave that to speculation for now.
2519
2520 # If the "subname" isn't all digits, we'll assume it
2521 # is a subroutine name, and try to find it.
e22ea7cc
RF
2522 if ( $subname =~ /\D/ ) { # subroutine name
2523 # Qualify it to the current package unless it's
2524 # already qualified.
69893cff
RGS
2525 $subname = $package . "::" . $subname
2526 unless $subname =~ /::/;
e22ea7cc 2527
69893cff
RGS
2528 # find_sub will return "file:line_number" corresponding
2529 # to where the subroutine is defined; we call find_sub,
e22ea7cc 2530 # break up the return value, and assign it in one
69893cff 2531 # operation.
e22ea7cc 2532 ( $file, $i ) = ( find_sub($subname) =~ /^(.*):(.*)$/ );
69893cff
RGS
2533
2534 # Force the line number to be numeric.
e22ea7cc 2535 $i += 0;
69893cff
RGS
2536
2537 # If we got a line number, we found the sub.
e22ea7cc
RF
2538 if ($i) {
2539
69893cff
RGS
2540 # Switch all the debugger's internals around so
2541 # we're actually working with that file.
e22ea7cc
RF
2542 $filename = $file;
2543 *dbline = $main::{ '_<' . $filename };
2544
69893cff 2545 # Mark that there's a breakpoint in this file.
e22ea7cc
RF
2546 $had_breakpoints{$filename} |= 1;
2547
69893cff
RGS
2548 # Scan forward to the first executable line
2549 # after the 'sub whatever' line.
e22ea7cc
RF
2550 $max = $#dbline;
2551 ++$i while $dbline[$i] == 0 && $i < $max;
2552 } ## end if ($i)
69893cff
RGS
2553
2554 # We didn't find a sub by that name.
e22ea7cc
RF
2555 else {
2556 print $OUT "Subroutine $subname not found.\n";
2557 next CMD;
2558 }
2559 } ## end if ($subname =~ /\D/)
69893cff
RGS
2560
2561 # At this point, either the subname was all digits (an
2562 # absolute line-break request) or we've scanned through
2563 # the code following the definition of the sub, looking
2564 # for an executable, which we may or may not have found.
2565 #
2566 # If $i (which we set $subname from) is non-zero, we
e22ea7cc
RF
2567 # got a request to break at some line somewhere. On
2568 # one hand, if there wasn't any real subroutine name
2569 # involved, this will be a request to break in the current
2570 # file at the specified line, so we have to check to make
69893cff
RGS
2571 # sure that the line specified really is breakable.
2572 #
2573 # On the other hand, if there was a subname supplied, the
3c4b39be 2574 # preceding block has moved us to the proper file and
69893cff
RGS
2575 # location within that file, and then scanned forward
2576 # looking for the next executable line. We have to make
2577 # sure that one was found.
2578 #
2579 # On the gripping hand, we can't do anything unless the
2580 # current value of $i points to a valid breakable line.
2581 # Check that.
e22ea7cc
RF
2582 if ($i) {
2583
69893cff 2584 # Breakable?
e22ea7cc
RF
2585 if ( $dbline[$i] == 0 ) {
2586 print $OUT "Line $i not breakable.\n";
2587 next CMD;
2588 }
2589
69893cff 2590 # Yes. Set up the one-time-break sigil.
e22ea7cc 2591 $dbline{$i} =~ s/($|\0)/;9$1/; # add one-time-only b.p.
5d5d9ea3 2592 _enable_breakpoint_temp_enabled_status($filename, $i);
e22ea7cc 2593 } ## end if ($i)
69893cff
RGS
2594
2595 # Turn off stack tracing from here up.
2c247e84
SF
2596 for my $i (0 .. $stack_depth) {
2597 $stack[ $i ] &= ~1;
e22ea7cc
RF
2598 }
2599 last CMD;
ef18ae63 2600 }
69893cff
RGS
2601
2602=head4 C<r> - return from a subroutine
2603
2604For C<r> to work properly, the debugger has to stop execution again
2605immediately after the return is executed. This is done by forcing
2606single-stepping to be on in the call level above the current one. If
2607we are printing return values when a C<r> is executed, set C<$doret>
2608appropriately, and force us out of the command loop.
2609
2610=cut
2611
2612 # r - return from the current subroutine.
ef18ae63 2613 if ($cmd eq 'r') {
e22ea7cc 2614
98dc9551 2615 # Can't do anything if the program's over.
1750bb2a
SF
2616 if ($finished and $level <= 1) {
2617 end_report();
2618 next CMD;
2619 }
e22ea7cc 2620
69893cff 2621 # Turn on stack trace.
e22ea7cc
RF
2622 $stack[$stack_depth] |= 1;
2623
69893cff 2624 # Print return value unless the stack is empty.
e22ea7cc
RF
2625 $doret = $option{PrintRet} ? $stack_depth - 1 : -2;
2626 last CMD;
ef18ae63 2627 }
69893cff 2628
69893cff
RGS
2629=head4 C<T> - stack trace
2630
2631Just calls C<DB::print_trace>.
2632
2633=cut
2634
ef18ae63 2635 if ($cmd eq 'T') {
e22ea7cc
RF
2636 print_trace( $OUT, 1 ); # skip DB
2637 next CMD;
ef18ae63 2638 }
69893cff
RGS
2639
2640=head4 C<w> - List window around current line.
2641
2642Just calls C<DB::cmd_w>.
2643
2644=cut
2645
ef18ae63
SF
2646 if (my ($arg) = $cmd =~ /\Aw\b\s*(.*)/s) {
2647 &cmd_w( 'w', $arg );
2648 next CMD;
2649 }
69893cff
RGS
2650
2651=head4 C<W> - watch-expression processing.
2652
b570d64b 2653Just calls C<DB::cmd_W>.
69893cff
RGS
2654
2655=cut
2656
ef18ae63
SF
2657 if (my ($arg) = $cmd =~ /\AW\b\s*(.*)/s) {
2658 &cmd_W( 'W', $arg );
2659 next CMD;
2660 }
69893cff
RGS
2661
2662=head4 C</> - search forward for a string in the source
2663
ef18ae63 2664We take the argument and treat it as a pattern. If it turns out to be a
69893cff 2665bad one, we return the error we got from trying to C<eval> it and exit.
ef18ae63 2666If not, we create some code to do the search and C<eval> it so it can't
69893cff
RGS
2667mess us up.
2668
2669=cut
2670
ef18ae63
SF
2671 # The pattern as a string.
2672 use vars qw($inpat);
69893cff 2673
ef18ae63 2674 if (($inpat) = $cmd =~ m#\A/(.*)\z#) {
69893cff
RGS
2675
2676 # Remove the final slash.
e22ea7cc 2677 $inpat =~ s:([^\\])/$:$1:;
69893cff
RGS
2678
2679 # If the pattern isn't null ...
e22ea7cc 2680 if ( $inpat ne "" ) {
69893cff
RGS
2681
2682 # Turn of warn and die procesing for a bit.
e22ea7cc
RF
2683 local $SIG{__DIE__};
2684 local $SIG{__WARN__};
69893cff
RGS
2685
2686 # Create the pattern.
22fc883d 2687 eval 'no strict q/vars/; $inpat =~ m' . "\a$inpat\a";
e22ea7cc
RF
2688 if ( $@ ne "" ) {
2689
69893cff 2690 # Oops. Bad pattern. No biscuit.
e22ea7cc 2691 # Print the eval error and go back for more
69893cff 2692 # commands.
e22ea7cc
RF
2693 print $OUT "$@";
2694 next CMD;
2695 }
2696 $pat = $inpat;
2697 } ## end if ($inpat ne "")
69893cff
RGS
2698
2699 # Set up to stop on wrap-around.
e22ea7cc 2700 $end = $start;
69893cff
RGS
2701
2702 # Don't move off the current line.
e22ea7cc 2703 $incr = -1;
69893cff
RGS
2704
2705 # Done in eval so nothing breaks if the pattern
2706 # does something weird.
e22ea7cc 2707 eval '
22fc883d 2708 no strict q/vars/;
e22ea7cc 2709 for (;;) {
69893cff 2710 # Move ahead one line.
e22ea7cc 2711 ++$start;
69893cff
RGS
2712
2713 # Wrap if we pass the last line.
e22ea7cc 2714 $start = 1 if ($start > $max);
69893cff
RGS
2715
2716 # Stop if we have gotten back to this line again,
e22ea7cc 2717 last if ($start == $end);
69893cff
RGS
2718
2719 # A hit! (Note, though, that we are doing
2720 # case-insensitive matching. Maybe a qr//
2721 # expression would be better, so the user could
2722 # do case-sensitive matching if desired.
e22ea7cc
RF
2723 if ($dbline[$start] =~ m' . "\a$pat\a" . 'i) {
2724 if ($slave_editor) {
69893cff 2725 # Handle proper escaping in the slave.
e22ea7cc 2726 print $OUT "\032\032$filename:$start:0\n";
b570d64b 2727 }
e22ea7cc 2728 else {
69893cff 2729 # Just print the line normally.
e22ea7cc
RF
2730 print $OUT "$start:\t",$dbline[$start],"\n";
2731 }
69893cff 2732 # And quit since we found something.
e22ea7cc
RF
2733 last;
2734 }
2735 } ';
2736
69893cff 2737 # If we wrapped, there never was a match.
e22ea7cc
RF
2738 print $OUT "/$pat/: not found\n" if ( $start == $end );
2739 next CMD;
ef18ae63 2740 }
69893cff
RGS
2741
2742=head4 C<?> - search backward for a string in the source
2743
2744Same as for C</>, except the loop runs backwards.
2745
2746=cut
2747
2748 # ? - backward pattern search.
ef18ae63 2749 if (my ($inpat) = $cmd =~ m#\A\?(.*)\z#) {
69893cff
RGS
2750
2751 # Get the pattern, remove trailing question mark.
e22ea7cc 2752 $inpat =~ s:([^\\])\?$:$1:;
69893cff
RGS
2753
2754 # If we've got one ...
e22ea7cc 2755 if ( $inpat ne "" ) {
69893cff
RGS
2756
2757 # Turn off die & warn handlers.
e22ea7cc
RF
2758 local $SIG{__DIE__};
2759 local $SIG{__WARN__};
2760 eval '$inpat =~ m' . "\a$inpat\a";
2761
2762 if ( $@ ne "" ) {
2763
69893cff 2764 # Ouch. Not good. Print the error.
e22ea7cc
RF
2765 print $OUT $@;
2766 next CMD;
2767 }
2768 $pat = $inpat;
69893cff 2769 } ## end if ($inpat ne "")
e22ea7cc 2770
69893cff 2771 # Where we are now is where to stop after wraparound.
e22ea7cc 2772 $end = $start;
69893cff
RGS
2773
2774 # Don't move away from this line.
e22ea7cc 2775 $incr = -1;
69893cff
RGS
2776
2777 # Search inside the eval to prevent pattern badness
2778 # from killing us.
e22ea7cc 2779 eval '
22fc883d 2780 no strict q/vars/;
e22ea7cc 2781 for (;;) {
69893cff 2782 # Back up a line.
e22ea7cc 2783 --$start;
69893cff
RGS
2784
2785 # Wrap if we pass the first line.
e22ea7cc
RF
2786
2787 $start = $max if ($start <= 0);
69893cff
RGS
2788
2789 # Quit if we get back where we started,
e22ea7cc 2790 last if ($start == $end);
69893cff
RGS
2791
2792 # Match?
e22ea7cc
RF
2793 if ($dbline[$start] =~ m' . "\a$pat\a" . 'i) {
2794 if ($slave_editor) {
69893cff 2795 # Yep, follow slave editor requirements.
e22ea7cc 2796 print $OUT "\032\032$filename:$start:0\n";
b570d64b 2797 }
e22ea7cc 2798 else {
69893cff 2799 # Yep, just print normally.
e22ea7cc
RF
2800 print $OUT "$start:\t",$dbline[$start],"\n";
2801 }
69893cff
RGS
2802
2803 # Found, so done.
e22ea7cc
RF
2804 last;
2805 }
2806 } ';
2807
2808 # Say we failed if the loop never found anything,
2809 print $OUT "?$pat?: not found\n" if ( $start == $end );
2810 next CMD;
ef18ae63 2811 }
69893cff
RGS
2812
2813=head4 C<$rc> - Recall command
2814
2815Manages the commands in C<@hist> (which is created if C<Term::ReadLine> reports
2816that the terminal supports history). It find the the command required, puts it
2817into C<$cmd>, and redoes the loop to execute it.
2818
2819=cut
2820
e22ea7cc 2821 # $rc - recall command.
ef18ae63 2822 if (my ($minus, $arg) = $cmd =~ m#\A$rc+\s*(-)?(\d+)?\z#) {
69893cff
RGS
2823
2824 # No arguments, take one thing off history.
e22ea7cc 2825 pop(@hist) if length($cmd) > 1;
69893cff 2826
e22ea7cc 2827 # Relative (- found)?
69893cff 2828 # Y - index back from most recent (by 1 if bare minus)
e22ea7cc 2829 # N - go to that particular command slot or the last
69893cff 2830 # thing if nothing following.
ef18ae63 2831 $i = $minus ? ( $#hist - ( $arg || 1 ) ) : ( $arg || $#hist );
69893cff
RGS
2832
2833 # Pick out the command desired.
e22ea7cc 2834 $cmd = $hist[$i];
69893cff
RGS
2835
2836 # Print the command to be executed and restart the loop
2837 # with that command in the buffer.
e22ea7cc
RF
2838 print $OUT $cmd, "\n";
2839 redo CMD;
ef18ae63 2840 }
69893cff
RGS
2841
2842=head4 C<$sh$sh> - C<system()> command
2843
2844Calls the C<DB::system()> to handle the command. This keeps the C<STDIN> and
2845C<STDOUT> from getting messed up.
2846
2847=cut
2848
2849 # $sh$sh - run a shell command (if it's all ASCII).
2850 # Can't run shell commands with Unicode in the debugger, hmm.
ef18ae63 2851 if (my ($arg) = $cmd =~ m#\A$sh$sh\s*(.*)#ms) {
e22ea7cc 2852
69893cff 2853 # System it.
ef18ae63 2854 &system($arg);
e22ea7cc 2855 next CMD;
ef18ae63 2856 }
69893cff
RGS
2857
2858=head4 C<$rc I<pattern> $rc> - Search command history
2859
2860Another command to manipulate C<@hist>: this one searches it with a pattern.
be9a9b1d 2861If a command is found, it is placed in C<$cmd> and executed via C<redo>.
69893cff
RGS
2862
2863=cut
2864
e22ea7cc 2865 # $rc pattern $rc - find a command in the history.
ef18ae63 2866 if (my ($arg) = $cmd =~ /\A$rc([^$rc].*)\z/) {
e22ea7cc 2867
69893cff 2868 # Create the pattern to use.
ef18ae63 2869 $pat = "^$arg";
69893cff
RGS
2870
2871 # Toss off last entry if length is >1 (and it always is).
e22ea7cc 2872 pop(@hist) if length($cmd) > 1;
69893cff
RGS
2873
2874 # Look backward through the history.
72d7d80d 2875 for ( $i = $#hist ; $i ; --$i ) {
69893cff 2876 # Stop if we find it.
e22ea7cc
RF
2877 last if $hist[$i] =~ /$pat/;
2878 }
2879
2880 if ( !$i ) {
69893cff 2881
69893cff 2882 # Never found it.
e22ea7cc
RF
2883 print $OUT "No such command!\n\n";
2884 next CMD;
2885 }
69893cff
RGS
2886
2887 # Found it. Put it in the buffer, print it, and process it.
e22ea7cc
RF
2888 $cmd = $hist[$i];
2889 print $OUT $cmd, "\n";
2890 redo CMD;
ef18ae63 2891 }
69893cff 2892
ef18ae63 2893=head4 C<$sh> - Invoke a shell
69893cff
RGS
2894
2895Uses C<DB::system> to invoke a shell.
2896
2897=cut
2898
2899 # $sh - start a shell.
ef18ae63 2900 if ($cmd =~ /\A$sh\z/) {
e22ea7cc 2901
69893cff
RGS
2902 # Run the user's shell. If none defined, run Bourne.
2903 # We resume execution when the shell terminates.
e22ea7cc
RF
2904 &system( $ENV{SHELL} || "/bin/sh" );
2905 next CMD;
ef18ae63 2906 }
69893cff
RGS
2907
2908=head4 C<$sh I<command>> - Force execution of a command in a shell
2909
2910Like the above, but the command is passed to the shell. Again, we use
2911C<DB::system> to avoid problems with C<STDIN> and C<STDOUT>.
2912
2913=cut
2914
2915 # $sh command - start a shell and run a command in it.
ef18ae63 2916 if (my ($arg) = $cmd =~ m#\A$sh\s*(.*)#ms) {
e22ea7cc
RF
2917
2918 # XXX: using csh or tcsh destroys sigint retvals!
2919 #&system($1); # use this instead
69893cff
RGS
2920
2921 # use the user's shell, or Bourne if none defined.
ef18ae63 2922 &system( $ENV{SHELL} || "/bin/sh", "-c", $arg );
e22ea7cc 2923 next CMD;
ef18ae63 2924 }
69893cff
RGS
2925
2926=head4 C<H> - display commands in history
2927
2928Prints the contents of C<@hist> (if any).
2929
2930=cut
2931
ef18ae63 2932 if ($cmd =~ /\AH\b\s*\*/) {
7fddc82f
RF
2933 @hist = @truehist = ();
2934 print $OUT "History cleansed\n";
2935 next CMD;
ef18ae63 2936 }
e22ea7cc 2937
ef18ae63
SF
2938 if (my ($num)
2939 = $cmd =~ /\AH\b\s*(?:-(\d+))?/) {
e22ea7cc
RF
2940
2941 # Anything other than negative numbers is ignored by
69893cff 2942 # the (incorrect) pattern, so this test does nothing.
ef18ae63 2943 $end = $num ? ( $#hist - $num ) : 0;
69893cff
RGS
2944
2945 # Set to the minimum if less than zero.
e22ea7cc 2946 $hist = 0 if $hist < 0;
69893cff 2947
e22ea7cc 2948 # Start at the end of the array.
69893cff
RGS
2949 # Stay in while we're still above the ending value.
2950 # Tick back by one each time around the loop.
72d7d80d 2951 for ( $i = $#hist ; $i > $end ; $i-- ) {
69893cff
RGS
2952
2953 # Print the command unless it has no arguments.
e22ea7cc
RF
2954 print $OUT "$i: ", $hist[$i], "\n"
2955 unless $hist[$i] =~ /^.?$/;
2956 }
2957 next CMD;
ef18ae63 2958 }
69893cff
RGS
2959
2960=head4 C<man, doc, perldoc> - look up documentation
2961
2962Just calls C<runman()> to print the appropriate document.
2963
2964=cut
2965
e22ea7cc 2966 # man, perldoc, doc - show manual pages.
ef18ae63
SF
2967 if (my ($man_page)
2968 = $cmd =~ /\A(?:man|(?:perl)?doc)\b(?:\s+([^(]*))?\z/) {
2969 runman($man_page);
e22ea7cc 2970 next CMD;
ef18ae63 2971 }
69893cff
RGS
2972
2973=head4 C<p> - print
2974
2975Builds a C<print EXPR> expression in the C<$cmd>; this will get executed at
2976the bottom of the loop.
2977
2978=cut
2979
ef18ae63 2980 my $print_cmd = 'print {$DB::OUT} ';
69893cff 2981 # p - print (no args): print $_.
ef18ae63
SF
2982 if ($cmd eq 'p') {
2983 $cmd = $print_cmd . '$_';
2984 }
69893cff
RGS
2985
2986 # p - print the given expression.
ef18ae63 2987 $cmd =~ s/\Ap\b/$print_cmd /;
69893cff
RGS
2988
2989=head4 C<=> - define command alias
2990
2991Manipulates C<%alias> to add or list command aliases.
2992
2993=cut
2994
e22ea7cc 2995 # = - set up a command alias.
ef18ae63 2996 if ($cmd =~ s/\A=\s*//) {
e22ea7cc
RF
2997 my @keys;
2998 if ( length $cmd == 0 ) {
2999
69893cff 3000 # No args, get current aliases.
e22ea7cc
RF
3001 @keys = sort keys %alias;
3002 }
3003 elsif ( my ( $k, $v ) = ( $cmd =~ /^(\S+)\s+(\S.*)/ ) ) {
3004
69893cff
RGS
3005 # Creating a new alias. $k is alias name, $v is
3006 # alias value.
3007
e22ea7cc
RF
3008 # can't use $_ or kill //g state
3009 for my $x ( $k, $v ) {
3010
3011 # Escape "alarm" characters.
3012 $x =~ s/\a/\\a/g;
3013 }
69893cff
RGS
3014
3015 # Substitute key for value, using alarm chars
e22ea7cc 3016 # as separators (which is why we escaped them in
69893cff 3017 # the command).
e22ea7cc 3018 $alias{$k} = "s\a$k\a$v\a";
69893cff
RGS
3019
3020 # Turn off standard warn and die behavior.
e22ea7cc
RF
3021 local $SIG{__DIE__};
3022 local $SIG{__WARN__};
69893cff
RGS
3023
3024 # Is it valid Perl?
e22ea7cc
RF
3025 unless ( eval "sub { s\a$k\a$v\a }; 1" ) {
3026
69893cff 3027 # Nope. Bad alias. Say so and get out.
e22ea7cc
RF
3028 print $OUT "Can't alias $k to $v: $@\n";
3029 delete $alias{$k};
3030 next CMD;
3031 }
3032
69893cff 3033 # We'll only list the new one.
e22ea7cc 3034 @keys = ($k);
69893cff
RGS
3035 } ## end elsif (my ($k, $v) = ($cmd...
3036
3037 # The argument is the alias to list.
e22ea7cc
RF
3038 else {
3039 @keys = ($cmd);
3040 }
69893cff
RGS
3041
3042 # List aliases.
e22ea7cc
RF
3043 for my $k (@keys) {
3044
98dc9551 3045 # Messy metaquoting: Trim the substitution code off.
69893cff
RGS
3046 # We use control-G as the delimiter because it's not
3047 # likely to appear in the alias.
e22ea7cc
RF
3048 if ( ( my $v = $alias{$k} ) =~ s\as\a$k\a(.*)\a$\a1\a ) {
3049
69893cff 3050 # Print the alias.
e22ea7cc
RF
3051 print $OUT "$k\t= $1\n";
3052 }
3053 elsif ( defined $alias{$k} ) {
3054
69893cff 3055 # Couldn't trim it off; just print the alias code.
e22ea7cc
RF
3056 print $OUT "$k\t$alias{$k}\n";
3057 }
3058 else {
3059
69893cff 3060 # No such, dude.
e22ea7cc
RF
3061 print "No alias for $k\n";
3062 }
69893cff 3063 } ## end for my $k (@keys)
e22ea7cc 3064 next CMD;
ef18ae63 3065 }
69893cff
RGS
3066
3067=head4 C<source> - read commands from a file.
3068
3069Opens a lexical filehandle and stacks it on C<@cmdfhs>; C<DB::readline> will
3070pick it up.
3071
3072=cut
3073
e22ea7cc 3074 # source - read commands from a file (or pipe!) and execute.
ef18ae63
SF
3075 if (my ($sourced_fn) = $cmd =~ /\Asource\s+(.*\S)/) {
3076 if ( open my $fh, $sourced_fn ) {
e22ea7cc 3077
69893cff 3078 # Opened OK; stick it in the list of file handles.
e22ea7cc
RF
3079 push @cmdfhs, $fh;
3080 }
3081 else {
3082
3083 # Couldn't open it.
ef18ae63 3084 &warn("Can't execute '$sourced_fn': $!\n");
e22ea7cc
RF
3085 }
3086 next CMD;
ef18ae63 3087 }
69893cff 3088
ef18ae63
SF
3089 if (my ($which_cmd, $position)
3090 = $cmd =~ /^(enable|disable)\s+(\S+)\s*$/) {
e09195af
SF
3091
3092 my ($fn, $line_num);
3093 if ($position =~ m{\A\d+\z})
3094 {
3095 $fn = $filename;
3096 $line_num = $position;
3097 }
ef18ae63
SF
3098 elsif (my ($new_fn, $new_line_num)
3099 = $position =~ m{\A(.*):(\d+)\z}) {
3100 ($fn, $line_num) = ($new_fn, $new_line_num);
e09195af
SF
3101 }
3102 else
3103 {
3104 &warn("Wrong spec for enable/disable argument.\n");
3105 }
3106
3107 if (defined($fn)) {
3108 if (_has_breakpoint_data_ref($fn, $line_num)) {
3109 _set_breakpoint_enabled_status($fn, $line_num,
ef18ae63 3110 ($which_cmd eq 'enable' ? 1 : '')
e09195af
SF
3111 );
3112 }
3113 else {
3114 &warn("No breakpoint set at ${fn}:${line_num}\n");
3115 }
3116 }
3117
3118 next CMD;
ef18ae63 3119 }
e09195af 3120
69893cff
RGS
3121=head4 C<save> - send current history to a file
3122
3123Takes the complete history, (not the shrunken version you see with C<H>),
3124and saves it to the given filename, so it can be replayed using C<source>.
3125
3126Note that all C<^(save|source)>'s are commented out with a view to minimise recursion.
3127
3128=cut
3129
3130 # save source - write commands to a file for later use
ef18ae63
SF
3131 if (my ($new_fn) = $cmd =~ /\Asave\s*(.*)\z/) {
3132 my $filename = $new_fn || '.perl5dbrc'; # default?
3133 if ( open my $fh, '>', $filename ) {
e22ea7cc
RF
3134
3135 # chomp to remove extraneous newlines from source'd files
3136 chomp( my @truelist =
3137 map { m/^\s*(save|source)/ ? "#$_" : $_ }
3138 @truehist );
3139 print $fh join( "\n", @truelist );
69893cff 3140 print "commands saved in $file\n";
e22ea7cc
RF
3141 }
3142 else {
ef18ae63 3143 &warn("Can't save debugger commands in '$new_fn': $!\n");
69893cff
RGS
3144 }
3145 next CMD;
ef18ae63 3146 }
69893cff 3147
7fddc82f
RF
3148=head4 C<R> - restart
3149
ef18ae63 3150Restart the debugger session.
7fddc82f
RF
3151
3152=head4 C<rerun> - rerun the current session
3153
3154Return to any given position in the B<true>-history list
3155
3156=cut
3157
3158 # R - restart execution.
3159 # rerun - controlled restart execution.
ff41e38d
SF
3160 if (my ($cmd_cmd, $cmd_params) =
3161 $cmd =~ /\A((?:R)|(?:rerun\s*(.*)))\z/) {
3162 my @args = ($cmd_cmd eq 'R' ? restart() : rerun($cmd_params));
7fddc82f 3163
ca28b541
AP
3164 # Close all non-system fds for a clean restart. A more
3165 # correct method would be to close all fds that were not
3166 # open when the process started, but this seems to be
3167 # hard. See "debugger 'R'estart and open database
3168 # connections" on p5p.
3169
47d3bbda 3170 my $max_fd = 1024; # default if POSIX can't be loaded
ca28b541 3171 if (eval { require POSIX }) {
5332cc68 3172 eval { $max_fd = POSIX::sysconf(POSIX::_SC_OPEN_MAX()) };
ca28b541
AP
3173 }
3174
3175 if (defined $max_fd) {
3176 foreach ($^F+1 .. $max_fd-1) {
3177 next unless open FD_TO_CLOSE, "<&=$_";
3178 close(FD_TO_CLOSE);
3179 }
3180 }
3181
7fddc82f
RF
3182 # And run Perl again. We use exec() to keep the
3183 # PID stable (and that way $ini_pids is still valid).
3184 exec(@args) || print $OUT "exec failed: $!\n";
3185
3186 last CMD;
ff41e38d 3187 }
7fddc82f 3188
69893cff
RGS
3189=head4 C<|, ||> - pipe output through the pager.
3190
be9a9b1d 3191For C<|>, we save C<OUT> (the debugger's output filehandle) and C<STDOUT>
69893cff
RGS
3192(the program's standard output). For C<||>, we only save C<OUT>. We open a
3193pipe to the pager (restoring the output filehandles if this fails). If this
b570d64b 3194is the C<|> command, we also set up a C<SIGPIPE> handler which will simply
69893cff
RGS
3195set C<$signal>, sending us back into the debugger.
3196
3197We then trim off the pipe symbols and C<redo> the command loop at the
3198C<PIPE> label, causing us to evaluate the command in C<$cmd> without
3199reading another.
3200
3201=cut
3202
3203 # || - run command in the pager, with output to DB::OUT.
ff41e38d 3204 if ($cmd =~ m#\A\|\|?\s*[^|]#) {
e22ea7cc
RF
3205 if ( $pager =~ /^\|/ ) {
3206
69893cff 3207 # Default pager is into a pipe. Redirect I/O.
e22ea7cc
RF
3208 open( SAVEOUT, ">&STDOUT" )
3209 || &warn("Can't save STDOUT");
3210 open( STDOUT, ">&OUT" )
3211 || &warn("Can't redirect STDOUT");
69893cff 3212 } ## end if ($pager =~ /^\|/)
e22ea7cc
RF
3213 else {
3214
69893cff 3215 # Not into a pipe. STDOUT is safe.
e22ea7cc
RF
3216 open( SAVEOUT, ">&OUT" ) || &warn("Can't save DB::OUT");
3217 }
69893cff
RGS
3218
3219 # Fix up environment to record we have less if so.
e22ea7cc
RF
3220 fix_less();
3221
3222 unless ( $piped = open( OUT, $pager ) ) {
69893cff 3223
69893cff 3224 # Couldn't open pipe to pager.
1f874cb6 3225 &warn("Can't pipe output to '$pager'");
e22ea7cc
RF
3226 if ( $pager =~ /^\|/ ) {
3227
69893cff 3228 # Redirect I/O back again.
e22ea7cc
RF
3229 open( OUT, ">&STDOUT" ) # XXX: lost message
3230 || &warn("Can't restore DB::OUT");
3231 open( STDOUT, ">&SAVEOUT" )
3232 || &warn("Can't restore STDOUT");
3233 close(SAVEOUT);
69893cff 3234 } ## end if ($pager =~ /^\|/)
e22ea7cc
RF
3235 else {
3236
69893cff 3237 # Redirect I/O. STDOUT already safe.
e22ea7cc
RF
3238 open( OUT, ">&STDOUT" ) # XXX: lost message
3239 || &warn("Can't restore DB::OUT");
3240 }
3241 next CMD;
69893cff
RGS
3242 } ## end unless ($piped = open(OUT,...
3243
3244 # Set up broken-pipe handler if necessary.
e22ea7cc
RF
3245 $SIG{PIPE} = \&DB::catch
3246 if $pager =~ /^\|/
3247 && ( "" eq $SIG{PIPE} || "DEFAULT" eq $SIG{PIPE} );
69893cff 3248
70c9432b
SF
3249 OUT->autoflush(1);
3250 # Save current filehandle, and put it back.
e22ea7cc 3251 $selected = select(OUT);
69893cff 3252 # Don't put it back if pager was a pipe.
e22ea7cc 3253 select($selected), $selected = "" unless $cmd =~ /^\|\|/;
69893cff
RGS
3254
3255 # Trim off the pipe symbols and run the command now.
ff41e38d 3256 $cmd =~ s#\A\|+\s*##;
e22ea7cc 3257 redo PIPE;
ff41e38d 3258 }
69893cff
RGS
3259
3260=head3 END OF COMMAND PARSING
3261
ff41e38d
SF
3262Anything left in C<$cmd> at this point is a Perl expression that we want to
3263evaluate. We'll always evaluate in the user's context, and fully qualify
69893cff
RGS
3264any variables we might want to address in the C<DB> package.
3265
3266=cut
3267
3268 # t - turn trace on.
ff41e38d
SF
3269 if ($cmd =~ s#\At\s+(\d+)?#\$DB::trace |= 1;\n#) {
3270 my $trace_arg = $1;
3271 $trace_to_depth = $trace_arg ? $stack_depth||0 + $1 : 1E9;
3272 }
69893cff
RGS
3273
3274 # s - single-step. Remember the last command was 's'.
ff41e38d
SF
3275 if ($cmd =~ s/\As\s/\$DB::single = 1;\n/) {
3276 $laststep = 's';
3277 }
69893cff
RGS
3278
3279 # n - single-step, but not into subs. Remember last command
e22ea7cc 3280 # was 'n'.
ff41e38d
SF
3281 if ($cmd =~ s#\An\s#\$DB::single = 2;\n#) {
3282 $laststep = 'n';
3283 }
69893cff 3284
e22ea7cc 3285 } # PIPE:
69893cff 3286
e22ea7cc 3287 # Make sure the flag that says "the debugger's running" is
69893cff 3288 # still on, to make sure we get control again.
e22ea7cc 3289 $evalarg = "\$^D = \$^D | \$DB::db_stop;\n$cmd";
69893cff
RGS
3290
3291 # Run *our* eval that executes in the caller's context.
7c54f46a 3292 DB::eval();
69893cff
RGS
3293
3294 # Turn off the one-time-dump stuff now.
e22ea7cc
RF
3295 if ($onetimeDump) {
3296 $onetimeDump = undef;
69893cff 3297 $onetimedumpDepth = undef;
e22ea7cc
RF
3298 }
3299 elsif ( $term_pid == $$ ) {
c7e68384
IZ
3300 eval { # May run under miniperl, when not available...
3301 STDOUT->flush();
3302 STDERR->flush();
3303 };
e22ea7cc 3304
69893cff 3305 # XXX If this is the master pid, print a newline.
e22ea7cc
RF
3306 print $OUT "\n";
3307 }
3308 } ## end while (($term || &setterm...
69893cff
RGS
3309
3310=head3 POST-COMMAND PROCESSING
3311
3312After each command, we check to see if the command output was piped anywhere.
3313If so, we go through the necessary code to unhook the pipe and go back to
3314our standard filehandles for input and output.
3315
3316=cut
3317
e22ea7cc 3318 continue { # CMD:
69893cff
RGS
3319
3320 # At the end of every command:
e22ea7cc
RF
3321 if ($piped) {
3322
69893cff 3323 # Unhook the pipe mechanism now.
e22ea7cc
RF
3324 if ( $pager =~ /^\|/ ) {
3325
69893cff 3326 # No error from the child.
e22ea7cc 3327 $? = 0;
69893cff 3328
e22ea7cc
RF
3329 # we cannot warn here: the handle is missing --tchrist
3330 close(OUT) || print SAVEOUT "\nCan't close DB::OUT\n";
69893cff 3331
e22ea7cc 3332 # most of the $? crud was coping with broken cshisms
69893cff 3333 # $? is explicitly set to 0, so this never runs.
e22ea7cc 3334 if ($?) {
1f874cb6 3335 print SAVEOUT "Pager '$pager' failed: ";
e22ea7cc
RF
3336 if ( $? == -1 ) {
3337 print SAVEOUT "shell returned -1\n";
3338 }
3339 elsif ( $? >> 8 ) {
3340 print SAVEOUT ( $? & 127 )
3341 ? " (SIG#" . ( $? & 127 ) . ")"
3342 : "", ( $? & 128 ) ? " -- core dumped" : "", "\n";
3343 }
3344 else {
3345 print SAVEOUT "status ", ( $? >> 8 ), "\n";
3346 }
69893cff
RGS
3347 } ## end if ($?)
3348
e22ea7cc 3349 # Reopen filehandle for our output (if we can) and
69893cff 3350 # restore STDOUT (if we can).
e22ea7cc
RF
3351 open( OUT, ">&STDOUT" ) || &warn("Can't restore DB::OUT");
3352 open( STDOUT, ">&SAVEOUT" )
3353 || &warn("Can't restore STDOUT");
69893cff
RGS
3354
3355 # Turn off pipe exception handler if necessary.
e22ea7cc 3356 $SIG{PIPE} = "DEFAULT" if $SIG{PIPE} eq \&DB::catch;
69893cff 3357
e22ea7cc
RF
3358 # Will stop ignoring SIGPIPE if done like nohup(1)
3359 # does SIGINT but Perl doesn't give us a choice.
69893cff 3360 } ## end if ($pager =~ /^\|/)
e22ea7cc
RF
3361 else {
3362
69893cff 3363 # Non-piped "pager". Just restore STDOUT.
e22ea7cc
RF
3364 open( OUT, ">&SAVEOUT" ) || &warn("Can't restore DB::OUT");
3365 }
69893cff
RGS
3366
3367 # Close filehandle pager was using, restore the normal one
3368 # if necessary,
3369 close(SAVEOUT);
e22ea7cc 3370 select($selected), $selected = "" unless $selected eq "";
69893cff
RGS
3371
3372 # No pipes now.
e22ea7cc 3373 $piped = "";
69893cff 3374 } ## end if ($piped)
e22ea7cc 3375 } # CMD:
69893cff
RGS
3376
3377=head3 COMMAND LOOP TERMINATION
3378
3379When commands have finished executing, we come here. If the user closed the
3380input filehandle, we turn on C<$fall_off_end> to emulate a C<q> command. We
3381evaluate any post-prompt items. We restore C<$@>, C<$!>, C<$^E>, C<$,>, C<$/>,
3382C<$\>, and C<$^W>, and return a null list as expected by the Perl interpreter.
3383The interpreter will then execute the next line and then return control to us
3384again.
3385
3386=cut
3387
3388 # No more commands? Quit.
1f874cb6 3389 $fall_off_end = 1 unless defined $cmd; # Emulate 'q' on EOF
69893cff
RGS
3390
3391 # Evaluate post-prompt commands.
e22ea7cc 3392 foreach $evalarg (@$post) {
7c54f46a 3393 DB::eval();
e22ea7cc
RF
3394 }
3395 } # if ($single || $signal)
69893cff
RGS
3396
3397 # Put the user's globals back where you found them.
e22ea7cc 3398 ( $@, $!, $^E, $,, $/, $\, $^W ) = @saved;
69893cff
RGS
3399 ();
3400} ## end sub DB
3401
22fc883d
SF
3402package DB::Obj;
3403
3404sub new {
3405 my $class = shift;
3406
3407 my $self = bless {}, $class;
3408
3409 $self->_init(@_);
3410
3411 return $self;
3412}
3413
3414sub _init {
3415 my ($self, $args) = @_;
3416
3417 %{$self} = (%$self, %$args);
3418
3419 return;
3420}
3421
3422{
3423 no strict 'refs';
3424 foreach my $slot_name (qw(after explicit_stop infix position prefix)) {
3425 my $slot = $slot_name;
3426 *{$slot} = sub {
3427 my $self = shift;
3428
3429 if (@_) {
3430 ${ $self->{$slot} } = shift;
3431 }
3432
3433 return ${ $self->{$slot} };
3434 };
8def6eff
SF
3435
3436 *{"append_to_$slot"} = sub {
3437 my $self = shift;
3438 my $s = shift;
3439
3440 return $self->$slot($self->$slot . $s);
3441 };
22fc883d
SF
3442 }
3443}
3444
3445sub _DB_on_init__initialize_globals
3446{
3447 my $self = shift;
3448
3449 # Check for whether we should be running continuously or not.
3450 # _After_ the perl program is compiled, $single is set to 1:
3451 if ( $DB::single and not $DB::second_time++ ) {
3452
3453 # Options say run non-stop. Run until we get an interrupt.
3454 if ($DB::runnonstop) { # Disable until signal
3455 # If there's any call stack in place, turn off single
3456 # stepping into subs throughout the stack.
3457 for my $i (0 .. $DB::stack_depth) {
3458 $DB::stack[ $i ] &= ~1;
3459 }
3460
3461 # And we are now no longer in single-step mode.
3462 $DB::single = 0;
3463
3464 # If we simply returned at this point, we wouldn't get
3465 # the trace info. Fall on through.
3466 # return;
3467 } ## end if ($runnonstop)
3468
3469 elsif ($DB::ImmediateStop) {
3470
3471 # We are supposed to stop here; XXX probably a break.
3472 $DB::ImmediateStop = 0; # We've processed it; turn it off
3473 $DB::signal = 1; # Simulate an interrupt to force
3474 # us into the command loop
3475 }
3476 } ## end if ($single and not $second_time...
3477
3478 # If we're in single-step mode, or an interrupt (real or fake)
3479 # has occurred, turn off non-stop mode.
3480 $DB::runnonstop = 0 if $DB::single or $DB::signal;
3481
3482 return;
3483}
3484
3485sub _DB__handle_watch_expressions
3486{
3487 my $self = shift;
3488
3489 if ( $DB::trace & 2 ) {
3490 for my $n (0 .. $#DB::to_watch) {
3491 $DB::evalarg = $DB::to_watch[$n];
3492 local $DB::onetimeDump; # Tell DB::eval() to not output results
3493
3494 # Fix context DB::eval() wants to return an array, but
3495 # we need a scalar here.
7c54f46a 3496 my ($val) = join( "', '", DB::eval() );
22fc883d
SF
3497 $val = ( ( defined $val ) ? "'$val'" : 'undef' );
3498
3499 # Did it change?
3500 if ( $val ne $DB::old_watch[$n] ) {
3501
3502 # Yep! Show the difference, and fake an interrupt.
3503 $DB::signal = 1;
3504 print {$DB::OUT} <<EOP;
3505Watchpoint $n:\t$DB::to_watch[$n] changed:
3506 old value:\t$DB::old_watch[$n]
3507 new value:\t$val
3508EOP
3509 $DB::old_watch[$n] = $val;
3510 } ## end if ($val ne $old_watch...
3511 } ## end for my $n (0 ..
3512 } ## end if ($trace & 2)
3513
3514 return;
3515}
3516
ad46ac70
SF
3517sub _my_print_lineinfo
3518{
3519 my ($self, $i, $incr_pos) = @_;
3520
3521 if ($DB::frame) {
3522 # Print it indented if tracing is on.
3523 DB::print_lineinfo( ' ' x $DB::stack_depth,
3524 "$i:\t$DB::dbline[$i]" . $self->after );
3525 }
3526 else {
3527 DB::depth_print_lineinfo($self->explicit_stop, $incr_pos);
3528 }
3529}
3530
44a07e3e
SF
3531sub _curr_line {
3532 return $DB::dbline[$DB::line];
3533}
3534
22fc883d
SF
3535sub _DB__grab_control
3536{
3537 my $self = shift;
3538
3539 # Yes, grab control.
3540 if ($DB::slave_editor) {
3541
3542 # Tell the editor to update its position.
3543 $self->position("\032\032${DB::filename}:${DB::line}:0\n");
3544 DB::print_lineinfo($self->position());
3545 }
3546
3547=pod
3548
3549Special check: if we're in package C<DB::fake>, we've gone through the
3550C<END> block at least once. We set up everything so that we can continue
3551to enter commands and have a valid context to be in.
3552
3553=cut
3554
3555 elsif ( $DB::package eq 'DB::fake' ) {
3556
3557 # Fallen off the end already.
3558 if (!$DB::term) {
3559 DB::setterm();
3560 }
3561
3562 DB::print_help(<<EOP);
3563Debugged program terminated. Use B<q> to quit or B<R> to restart,
3564use B<o> I<inhibit_exit> to avoid stopping after program termination,
3565B<h q>, B<h R> or B<h o> to get additional info.
3566EOP
3567
3568 # Set the DB::eval context appropriately.
3569 $DB::package = 'main';
3570 $DB::usercontext = DB::_calc_usercontext($DB::package);
3571 } ## end elsif ($package eq 'DB::fake')
3572
3573=pod
3574
3575If the program hasn't finished executing, we scan forward to the
3576next executable line, print that out, build the prompt from the file and line
3577number information, and print that.
3578
3579=cut
3580
3581 else {
3582
3583
3584 # Still somewhere in the midst of execution. Set up the
3585 # debugger prompt.
3586 $DB::sub =~ s/\'/::/; # Swap Perl 4 package separators (') to
3587 # Perl 5 ones (sorry, we don't print Klingon
3588 #module names)
3589
3590 $self->prefix($DB::sub =~ /::/ ? "" : ($DB::package . '::'));
8def6eff 3591 $self->append_to_prefix( "$DB::sub(${DB::filename}:" );
44a07e3e 3592 $self->after( $self->_curr_line =~ /\n$/ ? '' : "\n" );
22fc883d
SF
3593
3594 # Break up the prompt if it's really long.
3595 if ( length($self->prefix()) > 30 ) {
44a07e3e 3596 $self->position($self->prefix . "$DB::line):\n$DB::line:\t" . $self->_curr_line . $self->after);
22fc883d
SF
3597 $self->prefix("");
3598 $self->infix(":\t");
3599 }
3600 else {
3601 $self->infix("):\t");
3602 $self->position(
3603 $self->prefix . $DB::line. $self->infix
44a07e3e 3604 . $self->_curr_line . $self->after
22fc883d
SF
3605 );
3606 }
3607
3608 # Print current line info, indenting if necessary.