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e22ea7cc 1
b570d64b 2=head1 NAME
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be9a9b1d 4perl5db.pl - the perl debugger
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5
6=head1 SYNOPSIS
7
8 perl -d your_Perl_script
9
10=head1 DESCRIPTION
11
12C<perl5db.pl> is the perl debugger. It is loaded automatically by Perl when
13you invoke a script with C<perl -d>. This documentation tries to outline the
14structure and services provided by C<perl5db.pl>, and to describe how you
15can use them.
16
17=head1 GENERAL NOTES
18
19The debugger can look pretty forbidding to many Perl programmers. There are
20a number of reasons for this, many stemming out of the debugger's history.
21
22When the debugger was first written, Perl didn't have a lot of its nicer
23features - no references, no lexical variables, no closures, no object-oriented
24programming. So a lot of the things one would normally have done using such
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 *
69893cff 136
be9a9b1d 137First, doing an arithmetical or bitwise operation on a scalar is
69893cff 138just about the fastest thing you can do in Perl: C<use constant> actually
be9a9b1d 139creates a subroutine call, and array and hash lookups are much slower. Is
b570d64b 140this over-optimization at the expense of readability? Possibly, but the
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141debugger accesses these variables a I<lot>. Any rewrite of the code will
142probably have to benchmark alternate implementations and see which is the
b570d64b 143best balance of readability and speed, and then document how it actually
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144works.
145
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146=item *
147
b570d64b 148Second, it's very easy to serialize a scalar number. This is done in
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149the restart code; the debugger state variables are saved in C<%ENV> and then
150restored when the debugger is restarted. Having them be just numbers makes
b570d64b 151this trivial.
69893cff 152
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153=item *
154
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155Third, some of these variables are being shared with the Perl core
156smack in the middle of the interpreter's execution loop. It's much faster for
157a C program (like the interpreter) to check a bit in a scalar than to access
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158several different variables (or a Perl array).
159
160=back
161
162=head2 What are those C<XXX> comments for?
163
164Any comment containing C<XXX> means that the comment is either somewhat
b570d64b 165speculative - it's not exactly clear what a given variable or chunk of
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166code is doing, or that it is incomplete - the basics may be clear, but the
167subtleties are not completely documented.
168
169Send in a patch if you can clear up, fill out, or clarify an C<XXX>.
170
b570d64b 171=head1 DATA STRUCTURES MAINTAINED BY CORE
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172
173There are a number of special data structures provided to the debugger by
174the Perl interpreter.
175
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176The array C<@{$main::{'_<'.$filename}}> (aliased locally to C<@dbline>
177via glob assignment) contains the text from C<$filename>, with each
178element corresponding to a single line of C<$filename>. Additionally,
179breakable lines will be dualvars with the numeric component being the
180memory address of a COP node. Non-breakable lines are dualvar to 0.
69893cff 181
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182The hash C<%{'_<'.$filename}> (aliased locally to C<%dbline> via glob
183assignment) contains breakpoints and actions. The keys are line numbers;
184you can set individual values, but not the whole hash. The Perl interpreter
69893cff 185uses this hash to determine where breakpoints have been set. Any true value is
be9a9b1d 186considered to be a breakpoint; C<perl5db.pl> uses C<$break_condition\0$action>.
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187Values are magical in numeric context: 1 if the line is breakable, 0 if not.
188
ef18ae63 189The scalar C<${"_<$filename"}> simply contains the string C<<< _<$filename> >>>.
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190This is also the case for evaluated strings that contain subroutines, or
191which are currently being executed. The $filename for C<eval>ed strings looks
d24ca0c5 192like C<(eval 34).
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193
194=head1 DEBUGGER STARTUP
195
196When C<perl5db.pl> starts, it reads an rcfile (C<perl5db.ini> for
197non-interactive sessions, C<.perldb> for interactive ones) that can set a number
198of options. In addition, this file may define a subroutine C<&afterinit>
b570d64b 199that will be executed (in the debugger's context) after the debugger has
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200initialized itself.
201
b570d64b 202Next, it checks the C<PERLDB_OPTS> environment variable and treats its
be9a9b1d 203contents as the argument of a C<o> command in the debugger.
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204
205=head2 STARTUP-ONLY OPTIONS
206
207The following options can only be specified at startup.
208To set them in your rcfile, add a call to
209C<&parse_options("optionName=new_value")>.
210
211=over 4
212
b570d64b 213=item * TTY
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214
215the TTY to use for debugging i/o.
216
b570d64b 217=item * noTTY
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218
219if set, goes in NonStop mode. On interrupt, if TTY is not set,
b0e77abc 220uses the value of noTTY or F<$HOME/.perldbtty$$> to find TTY using
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221Term::Rendezvous. Current variant is to have the name of TTY in this
222file.
223
b570d64b 224=item * ReadLine
69893cff 225
5561b870 226if false, a dummy ReadLine is used, so you can debug
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227ReadLine applications.
228
b570d64b 229=item * NonStop
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230
231if true, no i/o is performed until interrupt.
232
b570d64b 233=item * LineInfo
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234
235file or pipe to print line number info to. If it is a
236pipe, a short "emacs like" message is used.
237
b570d64b 238=item * RemotePort
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239
240host:port to connect to on remote host for remote debugging.
241
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242=item * HistFile
243
244file to store session history to. There is no default and so no
245history file is written unless this variable is explicitly set.
246
247=item * HistSize
248
249number of commands to store to the file specified in C<HistFile>.
250Default is 100.
251
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252=back
253
254=head3 SAMPLE RCFILE
255
256 &parse_options("NonStop=1 LineInfo=db.out");
257 sub afterinit { $trace = 1; }
258
259The script will run without human intervention, putting trace
260information into C<db.out>. (If you interrupt it, you had better
be9a9b1d 261reset C<LineInfo> to something I<interactive>!)
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262
263=head1 INTERNALS DESCRIPTION
264
265=head2 DEBUGGER INTERFACE VARIABLES
266
267Perl supplies the values for C<%sub>. It effectively inserts
be9a9b1d 268a C<&DB::DB();> in front of each place that can have a
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269breakpoint. At each subroutine call, it calls C<&DB::sub> with
270C<$DB::sub> set to the called subroutine. It also inserts a C<BEGIN
271{require 'perl5db.pl'}> before the first line.
272
273After each C<require>d file is compiled, but before it is executed, a
274call to C<&DB::postponed($main::{'_<'.$filename})> is done. C<$filename>
275is the expanded name of the C<require>d file (as found via C<%INC>).
276
277=head3 IMPORTANT INTERNAL VARIABLES
278
279=head4 C<$CreateTTY>
280
281Used to control when the debugger will attempt to acquire another TTY to be
b570d64b 282used for input.
69893cff 283
b570d64b 284=over
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285
286=item * 1 - on C<fork()>
287
288=item * 2 - debugger is started inside debugger
289
290=item * 4 - on startup
291
292=back
293
294=head4 C<$doret>
295
296The value -2 indicates that no return value should be printed.
297Any other positive value causes C<DB::sub> to print return values.
298
299=head4 C<$evalarg>
300
301The item to be eval'ed by C<DB::eval>. Used to prevent messing with the current
302contents of C<@_> when C<DB::eval> is called.
303
304=head4 C<$frame>
305
306Determines what messages (if any) will get printed when a subroutine (or eval)
b570d64b 307is entered or exited.
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308
309=over 4
310
311=item * 0 - No enter/exit messages
312
be9a9b1d 313=item * 1 - Print I<entering> messages on subroutine entry
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314
315=item * 2 - Adds exit messages on subroutine exit. If no other flag is on, acts like 1+2.
316
be9a9b1d 317=item * 4 - Extended messages: C<< <in|out> I<context>=I<fully-qualified sub name> from I<file>:I<line> >>. If no other flag is on, acts like 1+4.
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318
319=item * 8 - Adds parameter information to messages, and overloaded stringify and tied FETCH is enabled on the printed arguments. Ignored if C<4> is not on.
320
321=item * 16 - Adds C<I<context> return from I<subname>: I<value>> messages on subroutine/eval exit. Ignored if C<4> is is not on.
322
323=back
324
be9a9b1d 325To get everything, use C<$frame=30> (or C<o f=30> as a debugger command).
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326The debugger internally juggles the value of C<$frame> during execution to
327protect external modules that the debugger uses from getting traced.
328
329=head4 C<$level>
330
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331Tracks current debugger nesting level. Used to figure out how many
332C<E<lt>E<gt>> pairs to surround the line number with when the debugger
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333outputs a prompt. Also used to help determine if the program has finished
334during command parsing.
335
336=head4 C<$onetimeDump>
337
338Controls what (if anything) C<DB::eval()> will print after evaluating an
339expression.
340
341=over 4
342
343=item * C<undef> - don't print anything
344
345=item * C<dump> - use C<dumpvar.pl> to display the value returned
346
347=item * C<methods> - print the methods callable on the first item returned
348
349=back
350
351=head4 C<$onetimeDumpDepth>
352
be9a9b1d 353Controls how far down C<dumpvar.pl> will go before printing C<...> while
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354dumping a structure. Numeric. If C<undef>, print all levels.
355
356=head4 C<$signal>
357
358Used to track whether or not an C<INT> signal has been detected. C<DB::DB()>,
359which is called before every statement, checks this and puts the user into
360command mode if it finds C<$signal> set to a true value.
361
362=head4 C<$single>
363
364Controls behavior during single-stepping. Stacked in C<@stack> on entry to
365each subroutine; popped again at the end of each subroutine.
366
b570d64b 367=over 4
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368
369=item * 0 - run continuously.
370
be9a9b1d 371=item * 1 - single-step, go into subs. The C<s> command.
69893cff 372
be9a9b1d 373=item * 2 - single-step, don't go into subs. The C<n> command.
69893cff 374
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375=item * 4 - print current sub depth (turned on to force this when C<too much
376recursion> occurs.
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377
378=back
379
380=head4 C<$trace>
381
b570d64b 382Controls the output of trace information.
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383
384=over 4
385
386=item * 1 - The C<t> command was entered to turn on tracing (every line executed is printed)
387
388=item * 2 - watch expressions are active
389
390=item * 4 - user defined a C<watchfunction()> in C<afterinit()>
391
392=back
393
394=head4 C<$slave_editor>
395
3961 if C<LINEINFO> was directed to a pipe; 0 otherwise.
397
398=head4 C<@cmdfhs>
399
400Stack of filehandles that C<DB::readline()> will read commands from.
401Manipulated by the debugger's C<source> command and C<DB::readline()> itself.
402
403=head4 C<@dbline>
404
b570d64b 405Local alias to the magical line array, C<@{$main::{'_<'.$filename}}> ,
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406supplied by the Perl interpreter to the debugger. Contains the source.
407
408=head4 C<@old_watch>
409
410Previous values of watch expressions. First set when the expression is
411entered; reset whenever the watch expression changes.
412
413=head4 C<@saved>
414
415Saves important globals (C<$@>, C<$!>, C<$^E>, C<$,>, C<$/>, C<$\>, C<$^W>)
416so that the debugger can substitute safe values while it's running, and
417restore them when it returns control.
418
419=head4 C<@stack>
420
421Saves the current value of C<$single> on entry to a subroutine.
422Manipulated by the C<c> command to turn off tracing in all subs above the
423current one.
424
425=head4 C<@to_watch>
426
427The 'watch' expressions: to be evaluated before each line is executed.
428
429=head4 C<@typeahead>
430
431The typeahead buffer, used by C<DB::readline>.
432
433=head4 C<%alias>
434
435Command aliases. Stored as character strings to be substituted for a command
436entered.
437
438=head4 C<%break_on_load>
439
440Keys are file names, values are 1 (break when this file is loaded) or undef
441(don't break when it is loaded).
442
443=head4 C<%dbline>
444
be9a9b1d 445Keys are line numbers, values are C<condition\0action>. If used in numeric
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446context, values are 0 if not breakable, 1 if breakable, no matter what is
447in the actual hash entry.
448
449=head4 C<%had_breakpoints>
450
451Keys are file names; values are bitfields:
452
b570d64b 453=over 4
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454
455=item * 1 - file has a breakpoint in it.
456
457=item * 2 - file has an action in it.
458
459=back
460
461A zero or undefined value means this file has neither.
462
463=head4 C<%option>
464
465Stores the debugger options. These are character string values.
466
467=head4 C<%postponed>
468
469Saves breakpoints for code that hasn't been compiled yet.
470Keys are subroutine names, values are:
471
472=over 4
473
be9a9b1d 474=item * C<compile> - break when this sub is compiled
69893cff 475
be9a9b1d 476=item * C<< break +0 if <condition> >> - break (conditionally) at the start of this routine. The condition will be '1' if no condition was specified.
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477
478=back
479
480=head4 C<%postponed_file>
481
482This hash keeps track of breakpoints that need to be set for files that have
483not yet been compiled. Keys are filenames; values are references to hashes.
484Each of these hashes is keyed by line number, and its values are breakpoint
be9a9b1d 485definitions (C<condition\0action>).
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486
487=head1 DEBUGGER INITIALIZATION
488
489The debugger's initialization actually jumps all over the place inside this
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490package. This is because there are several BEGIN blocks (which of course
491execute immediately) spread through the code. Why is that?
69893cff 492
b570d64b 493The debugger needs to be able to change some things and set some things up
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494before the debugger code is compiled; most notably, the C<$deep> variable that
495C<DB::sub> uses to tell when a program has recursed deeply. In addition, the
496debugger has to turn off warnings while the debugger code is compiled, but then
497restore them to their original setting before the program being debugged begins
498executing.
499
500The first C<BEGIN> block simply turns off warnings by saving the current
501setting of C<$^W> and then setting it to zero. The second one initializes
502the debugger variables that are needed before the debugger begins executing.
b570d64b 503The third one puts C<$^X> back to its former value.
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504
505We'll detail the second C<BEGIN> block later; just remember that if you need
506to initialize something before the debugger starts really executing, that's
507where it has to go.
508
509=cut
510
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511package DB;
512
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513use strict;
514
2dbd01ad 515BEGIN {eval 'use IO::Handle'}; # Needed for flush only? breaks under miniperl
9eba6a4e 516
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517BEGIN {
518 require feature;
519 $^V =~ /^v(\d+\.\d+)/;
520 feature->import(":$1");
521}
522
54d04a52 523# Debugger for Perl 5.00x; perl5db.pl patch level:
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524use vars qw($VERSION $header);
525
931d9438 526$VERSION = '1.39_05';
69893cff 527
e22ea7cc 528$header = "perl5db.pl version $VERSION";
d338d6fe 529
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530=head1 DEBUGGER ROUTINES
531
532=head2 C<DB::eval()>
533
534This function replaces straight C<eval()> inside the debugger; it simplifies
535the process of evaluating code in the user's context.
536
b570d64b 537The code to be evaluated is passed via the package global variable
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538C<$DB::evalarg>; this is done to avoid fiddling with the contents of C<@_>.
539
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540Before we do the C<eval()>, we preserve the current settings of C<$trace>,
541C<$single>, C<$^D> and C<$usercontext>. The latter contains the
542preserved values of C<$@>, C<$!>, C<$^E>, C<$,>, C<$/>, C<$\>, C<$^W> and the
543user's current package, grabbed when C<DB::DB> got control. This causes the
544proper context to be used when the eval is actually done. Afterward, we
545restore C<$trace>, C<$single>, and C<$^D>.
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546
547Next we need to handle C<$@> without getting confused. We save C<$@> in a
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548local lexical, localize C<$saved[0]> (which is where C<save()> will put
549C<$@>), and then call C<save()> to capture C<$@>, C<$!>, C<$^E>, C<$,>,
69893cff 550C<$/>, C<$\>, and C<$^W>) and set C<$,>, C<$/>, C<$\>, and C<$^W> to values
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551considered sane by the debugger. If there was an C<eval()> error, we print
552it on the debugger's output. If C<$onetimedump> is defined, we call
553C<dumpit> if it's set to 'dump', or C<methods> if it's set to
554'methods'. Setting it to something else causes the debugger to do the eval
555but not print the result - handy if you want to do something else with it
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556(the "watch expressions" code does this to get the value of the watch
557expression but not show it unless it matters).
558
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559In any case, we then return the list of output from C<eval> to the caller,
560and unwinding restores the former version of C<$@> in C<@saved> as well
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561(the localization of C<$saved[0]> goes away at the end of this scope).
562
563=head3 Parameters and variables influencing execution of DB::eval()
564
565C<DB::eval> isn't parameterized in the standard way; this is to keep the
566debugger's calls to C<DB::eval()> from mucking with C<@_>, among other things.
b570d64b 567The variables listed below influence C<DB::eval()>'s execution directly.
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568
569=over 4
570
571=item C<$evalarg> - the thing to actually be eval'ed
572
be9a9b1d 573=item C<$trace> - Current state of execution tracing
69893cff 574
be9a9b1d 575=item C<$single> - Current state of single-stepping
69893cff 576
b570d64b 577=item C<$onetimeDump> - what is to be displayed after the evaluation
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578
579=item C<$onetimeDumpDepth> - how deep C<dumpit()> should go when dumping results
580
581=back
582
583The following variables are altered by C<DB::eval()> during its execution. They
b570d64b 584are "stacked" via C<local()>, enabling recursive calls to C<DB::eval()>.
69893cff
RGS
585
586=over 4
587
588=item C<@res> - used to capture output from actual C<eval>.
589
590=item C<$otrace> - saved value of C<$trace>.
591
b570d64b 592=item C<$osingle> - saved value of C<$single>.
69893cff
RGS
593
594=item C<$od> - saved value of C<$^D>.
595
596=item C<$saved[0]> - saved value of C<$@>.
597
b570d64b 598=item $\ - for output of C<$@> if there is an evaluation error.
69893cff
RGS
599
600=back
601
602=head3 The problem of lexicals
603
604The context of C<DB::eval()> presents us with some problems. Obviously,
605we want to be 'sandboxed' away from the debugger's internals when we do
606the eval, but we need some way to control how punctuation variables and
b570d64b 607debugger globals are used.
69893cff
RGS
608
609We can't use local, because the code inside C<DB::eval> can see localized
610variables; and we can't use C<my> either for the same reason. The code
611in this routine compromises and uses C<my>.
612
613After this routine is over, we don't have user code executing in the debugger's
614context, so we can use C<my> freely.
615
616=cut
617
618############################################## Begin lexical danger zone
619
620# 'my' variables used here could leak into (that is, be visible in)
621# the context that the code being evaluated is executing in. This means that
622# the code could modify the debugger's variables.
623#
624# Fiddling with the debugger's context could be Bad. We insulate things as
625# much as we can.
626
6b24a4b7
SF
627use vars qw(
628 @args
629 %break_on_load
630 @cmdfhs
631 $CommandSet
632 $CreateTTY
633 $DBGR
634 @dbline
635 $dbline
636 %dbline
637 $dieLevel
6b24a4b7 638 $filename
6b24a4b7
SF
639 $hist
640 $histfile
641 $histsize
6b24a4b7
SF
642 $IN
643 $inhibit_exit
644 @ini_INC
645 $ini_warn
6b24a4b7
SF
646 $maxtrace
647 $od
6b24a4b7 648 $onetimedumpDepth
6b24a4b7
SF
649 @options
650 $osingle
651 $otrace
6b24a4b7
SF
652 $pager
653 $post
654 %postponed
655 $prc
656 $pre
657 $pretype
658 $psh
659 @RememberOnROptions
660 $remoteport
661 @res
662 $rl
663 @saved
6b24a4b7 664 $signalLevel
6b24a4b7
SF
665 $start
666 $sub
6b24a4b7 667 $term
6b24a4b7
SF
668 $usercontext
669 $warnLevel
670 $window
671);
672
0b83f3d9
SF
673our (
674 $evalarg,
675 $frame,
676 $ImmediateStop,
677 $line,
678 $onetimeDump,
1ce985d2 679 %option,
0b83f3d9 680 $OUT,
1ce985d2 681 $packname,
0b83f3d9
SF
682 $signal,
683 $single,
9d0b71b3
SF
684 %sub,
685 $subname,
0b83f3d9 686 $trace,
18b5b545 687);
931ac036 688
6b24a4b7
SF
689# Used to save @ARGV and extract any debugger-related flags.
690use vars qw(@ARGS);
691
692# Used to prevent multiple entries to diesignal()
693# (if for instance diesignal() itself dies)
694use vars qw($panic);
695
696# Used to prevent the debugger from running nonstop
697# after a restart
ebd0282e 698our ($second_time);
6b24a4b7
SF
699
700sub _calc_usercontext {
701 my ($package) = @_;
702
703 # Cancel strict completely for the evaluated code, so the code
704 # the user evaluates won't be affected by it. (Shlomi Fish)
22fc883d 705 return 'no strict; ($@, $!, $^E, $,, $/, $\, $^W) = @DB::saved;'
6b24a4b7
SF
706 . "package $package;"; # this won't let them modify, alas
707}
708
c1051fcf 709sub eval {
69893cff 710
c1051fcf 711 # 'my' would make it visible from user code
e22ea7cc 712 # but so does local! --tchrist
69893cff 713 # Remember: this localizes @DB::res, not @main::res.
c1051fcf
IZ
714 local @res;
715 {
e22ea7cc
RF
716
717 # Try to keep the user code from messing with us. Save these so that
718 # even if the eval'ed code changes them, we can put them back again.
719 # Needed because the user could refer directly to the debugger's
69893cff
RGS
720 # package globals (and any 'my' variables in this containing scope)
721 # inside the eval(), and we want to try to stay safe.
e22ea7cc 722 local $otrace = $trace;
69893cff
RGS
723 local $osingle = $single;
724 local $od = $^D;
725
726 # Untaint the incoming eval() argument.
727 { ($evalarg) = $evalarg =~ /(.*)/s; }
728
e22ea7cc 729 # $usercontext built in DB::DB near the comment
69893cff
RGS
730 # "set up the context for DB::eval ..."
731 # Evaluate and save any results.
e22ea7cc 732 @res = eval "$usercontext $evalarg;\n"; # '\n' for nice recursive debug
69893cff
RGS
733
734 # Restore those old values.
735 $trace = $otrace;
736 $single = $osingle;
737 $^D = $od;
c1051fcf 738 }
69893cff
RGS
739
740 # Save the current value of $@, and preserve it in the debugger's copy
741 # of the saved precious globals.
c1051fcf 742 my $at = $@;
69893cff
RGS
743
744 # Since we're only saving $@, we only have to localize the array element
745 # that it will be stored in.
e22ea7cc 746 local $saved[0]; # Preserve the old value of $@
7c54f46a 747 eval { DB::save() };
69893cff
RGS
748
749 # Now see whether we need to report an error back to the user.
c1051fcf 750 if ($at) {
69893cff
RGS
751 local $\ = '';
752 print $OUT $at;
753 }
754
755 # Display as required by the caller. $onetimeDump and $onetimedumpDepth
756 # are package globals.
757 elsif ($onetimeDump) {
e22ea7cc
RF
758 if ( $onetimeDump eq 'dump' ) {
759 local $option{dumpDepth} = $onetimedumpDepth
760 if defined $onetimedumpDepth;
761 dumpit( $OUT, \@res );
762 }
763 elsif ( $onetimeDump eq 'methods' ) {
764 methods( $res[0] );
765 }
69893cff 766 } ## end elsif ($onetimeDump)
c1051fcf 767 @res;
69893cff
RGS
768} ## end sub eval
769
770############################################## End lexical danger zone
c1051fcf 771
e22ea7cc
RF
772# After this point it is safe to introduce lexicals.
773# The code being debugged will be executing in its own context, and
69893cff 774# can't see the inside of the debugger.
d338d6fe 775#
e22ea7cc 776# However, one should not overdo it: leave as much control from outside as
69893cff
RGS
777# possible. If you make something a lexical, it's not going to be addressable
778# from outside the debugger even if you know its name.
779
d338d6fe
PP
780# This file is automatically included if you do perl -d.
781# It's probably not useful to include this yourself.
782#
e22ea7cc 783# Before venturing further into these twisty passages, it is
2f7e9187
MS
784# wise to read the perldebguts man page or risk the ire of dragons.
785#
69893cff
RGS
786# (It should be noted that perldebguts will tell you a lot about
787# the underlying mechanics of how the debugger interfaces into the
788# Perl interpreter, but not a lot about the debugger itself. The new
789# comments in this code try to address this problem.)
790
d338d6fe 791# Note that no subroutine call is possible until &DB::sub is defined
36477c24 792# (for subroutines defined outside of the package DB). In fact the same is
d338d6fe 793# true if $deep is not defined.
055fd3a9
GS
794
795# Enhanced by ilya@math.ohio-state.edu (Ilya Zakharevich)
055fd3a9
GS
796
797# modified Perl debugger, to be run from Emacs in perldb-mode
798# Ray Lischner (uunet!mntgfx!lisch) as of 5 Nov 1990
799# Johan Vromans -- upgrade to 4.0 pl 10
800# Ilya Zakharevich -- patches after 5.001 (and some before ;-)
6fae1ad7 801########################################################################
d338d6fe 802
69893cff
RGS
803=head1 DEBUGGER INITIALIZATION
804
805The debugger starts up in phases.
806
807=head2 BASIC SETUP
808
809First, it initializes the environment it wants to run in: turning off
810warnings during its own compilation, defining variables which it will need
811to avoid warnings later, setting itself up to not exit when the program
812terminates, and defaulting to printing return values for the C<r> command.
813
814=cut
815
eda6e075 816# Needed for the statement after exec():
69893cff
RGS
817#
818# This BEGIN block is simply used to switch off warnings during debugger
98dc9551 819# compilation. Probably it would be better practice to fix the warnings,
69893cff 820# but this is how it's done at the moment.
eda6e075 821
e22ea7cc
RF
822BEGIN {
823 $ini_warn = $^W;
824 $^W = 0;
825} # Switch compilation warnings off until another BEGIN.
d12a4851 826
69893cff
RGS
827local ($^W) = 0; # Switch run-time warnings off during init.
828
2cbb2ee1
RGS
829=head2 THREADS SUPPORT
830
831If we are running under a threaded Perl, we require threads and threads::shared
832if the environment variable C<PERL5DB_THREADED> is set, to enable proper
833threaded debugger control. C<-dt> can also be used to set this.
834
835Each new thread will be announced and the debugger prompt will always inform
836you of each new thread created. It will also indicate the thread id in which
837we are currently running within the prompt like this:
838
2dbd01ad 839 [tid] DB<$i>
2cbb2ee1
RGS
840
841Where C<[tid]> is an integer thread id and C<$i> is the familiar debugger
842command prompt. The prompt will show: C<[0]> when running under threads, but
843not actually in a thread. C<[tid]> is consistent with C<gdb> usage.
844
845While running under threads, when you set or delete a breakpoint (etc.), this
b570d64b 846will apply to all threads, not just the currently running one. When you are
2cbb2ee1
RGS
847in a currently executing thread, you will stay there until it completes. With
848the current implementation it is not currently possible to hop from one thread
849to another.
850
851The C<e> and C<E> commands are currently fairly minimal - see C<h e> and C<h E>.
852
853Note that threading support was built into the debugger as of Perl version
854C<5.8.6> and debugger version C<1.2.8>.
855
856=cut
857
858BEGIN {
2dbd01ad
SF
859 # ensure we can share our non-threaded variables or no-op
860 if ($ENV{PERL5DB_THREADED}) {
861 require threads;
862 require threads::shared;
863 import threads::shared qw(share);
864 $DBGR;
865 share(\$DBGR);
866 lock($DBGR);
867 print "Threads support enabled\n";
868 } else {
869 *lock = sub(*) {};
870 *share = sub(*) {};
871 }
2cbb2ee1
RGS
872}
873
2218c045
SF
874# These variables control the execution of 'dumpvar.pl'.
875{
876 package dumpvar;
877 use vars qw(
878 $hashDepth
879 $arrayDepth
880 $dumpDBFiles
881 $dumpPackages
882 $quoteHighBit
883 $printUndef
884 $globPrint
885 $usageOnly
886 );
887}
69893cff 888
2218c045
SF
889# used to control die() reporting in diesignal()
890{
891 package Carp;
892 use vars qw($CarpLevel);
893}
d338d6fe 894
422c59bf 895# without threads, $filename is not defined until DB::DB is called
2cbb2ee1 896foreach my $k (keys (%INC)) {
2dbd01ad 897 share(\$main::{'_<'.$filename}) if defined $filename;
2cbb2ee1
RGS
898};
899
54d04a52 900# Command-line + PERLLIB:
69893cff 901# Save the contents of @INC before they are modified elsewhere.
54d04a52
IZ
902@ini_INC = @INC;
903
69893cff
RGS
904# This was an attempt to clear out the previous values of various
905# trapped errors. Apparently it didn't help. XXX More info needed!
d338d6fe
PP
906# $prevwarn = $prevdie = $prevbus = $prevsegv = ''; # Does not help?!
907
69893cff
RGS
908# We set these variables to safe values. We don't want to blindly turn
909# off warnings, because other packages may still want them.
e22ea7cc
RF
910$trace = $signal = $single = 0; # Uninitialized warning suppression
911 # (local $^W cannot help - other packages!).
69893cff
RGS
912
913# Default to not exiting when program finishes; print the return
914# value when the 'r' command is used to return from a subroutine.
55497cff 915$inhibit_exit = $option{PrintRet} = 1;
d338d6fe 916
6b24a4b7
SF
917use vars qw($trace_to_depth);
918
5e2b42dd
SF
919# Default to 1E9 so it won't be limited to a certain recursion depth.
920$trace_to_depth = 1E9;
bdba49ad 921
69893cff
RGS
922=head1 OPTION PROCESSING
923
b570d64b
SF
924The debugger's options are actually spread out over the debugger itself and
925C<dumpvar.pl>; some of these are variables to be set, while others are
69893cff
RGS
926subs to be called with a value. To try to make this a little easier to
927manage, the debugger uses a few data structures to define what options
928are legal and how they are to be processed.
929
930First, the C<@options> array defines the I<names> of all the options that
931are to be accepted.
932
933=cut
934
935@options = qw(
5561b870 936 CommandSet HistFile HistSize
e22ea7cc
RF
937 hashDepth arrayDepth dumpDepth
938 DumpDBFiles DumpPackages DumpReused
939 compactDump veryCompact quote
940 HighBit undefPrint globPrint
941 PrintRet UsageOnly frame
942 AutoTrace TTY noTTY
943 ReadLine NonStop LineInfo
944 maxTraceLen recallCommand ShellBang
945 pager tkRunning ornaments
946 signalLevel warnLevel dieLevel
947 inhibit_exit ImmediateStop bareStringify
948 CreateTTY RemotePort windowSize
584420f0 949 DollarCaretP
e22ea7cc 950);
d12a4851 951
584420f0 952@RememberOnROptions = qw(DollarCaretP);
d12a4851 953
69893cff
RGS
954=pod
955
956Second, C<optionVars> lists the variables that each option uses to save its
957state.
958
959=cut
960
6b24a4b7
SF
961use vars qw(%optionVars);
962
69893cff 963%optionVars = (
e22ea7cc
RF
964 hashDepth => \$dumpvar::hashDepth,
965 arrayDepth => \$dumpvar::arrayDepth,
966 CommandSet => \$CommandSet,
967 DumpDBFiles => \$dumpvar::dumpDBFiles,
968 DumpPackages => \$dumpvar::dumpPackages,
969 DumpReused => \$dumpvar::dumpReused,
970 HighBit => \$dumpvar::quoteHighBit,
971 undefPrint => \$dumpvar::printUndef,
972 globPrint => \$dumpvar::globPrint,
973 UsageOnly => \$dumpvar::usageOnly,
974 CreateTTY => \$CreateTTY,
975 bareStringify => \$dumpvar::bareStringify,
976 frame => \$frame,
977 AutoTrace => \$trace,
978 inhibit_exit => \$inhibit_exit,
979 maxTraceLen => \$maxtrace,
980 ImmediateStop => \$ImmediateStop,
981 RemotePort => \$remoteport,
982 windowSize => \$window,
5561b870
AK
983 HistFile => \$histfile,
984 HistSize => \$histsize,
69893cff
RGS
985);
986
987=pod
988
989Third, C<%optionAction> defines the subroutine to be called to process each
990option.
991
b570d64b 992=cut
69893cff 993
6b24a4b7
SF
994use vars qw(%optionAction);
995
69893cff
RGS
996%optionAction = (
997 compactDump => \&dumpvar::compactDump,
998 veryCompact => \&dumpvar::veryCompact,
999 quote => \&dumpvar::quote,
1000 TTY => \&TTY,
1001 noTTY => \&noTTY,
1002 ReadLine => \&ReadLine,
1003 NonStop => \&NonStop,
1004 LineInfo => \&LineInfo,
1005 recallCommand => \&recallCommand,
1006 ShellBang => \&shellBang,
1007 pager => \&pager,
1008 signalLevel => \&signalLevel,
1009 warnLevel => \&warnLevel,
1010 dieLevel => \&dieLevel,
1011 tkRunning => \&tkRunning,
1012 ornaments => \&ornaments,
1013 RemotePort => \&RemotePort,
1014 DollarCaretP => \&DollarCaretP,
d12a4851
JH
1015);
1016
69893cff
RGS
1017=pod
1018
1019Last, the C<%optionRequire> notes modules that must be C<require>d if an
1020option is used.
1021
1022=cut
d338d6fe 1023
69893cff
RGS
1024# Note that this list is not complete: several options not listed here
1025# actually require that dumpvar.pl be loaded for them to work, but are
1026# not in the table. A subsequent patch will correct this problem; for
1027# the moment, we're just recommenting, and we are NOT going to change
1028# function.
6b24a4b7
SF
1029use vars qw(%optionRequire);
1030
eda6e075 1031%optionRequire = (
69893cff
RGS
1032 compactDump => 'dumpvar.pl',
1033 veryCompact => 'dumpvar.pl',
1034 quote => 'dumpvar.pl',
e22ea7cc 1035);
69893cff
RGS
1036
1037=pod
1038
1039There are a number of initialization-related variables which can be set
1040by putting code to set them in a BEGIN block in the C<PERL5DB> environment
1041variable. These are:
1042
1043=over 4
1044
1045=item C<$rl> - readline control XXX needs more explanation
1046
1047=item C<$warnLevel> - whether or not debugger takes over warning handling
1048
1049=item C<$dieLevel> - whether or not debugger takes over die handling
1050
1051=item C<$signalLevel> - whether or not debugger takes over signal handling
1052
1053=item C<$pre> - preprompt actions (array reference)
1054
1055=item C<$post> - postprompt actions (array reference)
1056
1057=item C<$pretype>
1058
1059=item C<$CreateTTY> - whether or not to create a new TTY for this debugger
1060
1061=item C<$CommandSet> - which command set to use (defaults to new, documented set)
1062
1063=back
1064
1065=cut
d338d6fe
PP
1066
1067# These guys may be defined in $ENV{PERL5DB} :
69893cff
RGS
1068$rl = 1 unless defined $rl;
1069$warnLevel = 1 unless defined $warnLevel;
1070$dieLevel = 1 unless defined $dieLevel;
1071$signalLevel = 1 unless defined $signalLevel;
1072$pre = [] unless defined $pre;
1073$post = [] unless defined $post;
1074$pretype = [] unless defined $pretype;
1075$CreateTTY = 3 unless defined $CreateTTY;
1076$CommandSet = '580' unless defined $CommandSet;
1077
2cbb2ee1
RGS
1078share($rl);
1079share($warnLevel);
1080share($dieLevel);
1081share($signalLevel);
1082share($pre);
1083share($post);
1084share($pretype);
1085share($rl);
1086share($CreateTTY);
1087share($CommandSet);
1088
69893cff
RGS
1089=pod
1090
1091The default C<die>, C<warn>, and C<signal> handlers are set up.
1092
1093=cut
055fd3a9 1094
d338d6fe
PP
1095warnLevel($warnLevel);
1096dieLevel($dieLevel);
1097signalLevel($signalLevel);
055fd3a9 1098
69893cff
RGS
1099=pod
1100
1101The pager to be used is needed next. We try to get it from the
5561b870 1102environment first. If it's not defined there, we try to find it in
69893cff
RGS
1103the Perl C<Config.pm>. If it's not there, we default to C<more>. We
1104then call the C<pager()> function to save the pager name.
1105
1106=cut
1107
1108# This routine makes sure $pager is set up so that '|' can use it.
4865a36d 1109pager(
e22ea7cc 1110
69893cff 1111 # If PAGER is defined in the environment, use it.
e22ea7cc
RF
1112 defined $ENV{PAGER}
1113 ? $ENV{PAGER}
69893cff
RGS
1114
1115 # If not, see if Config.pm defines it.
e22ea7cc
RF
1116 : eval { require Config }
1117 && defined $Config::Config{pager}
1118 ? $Config::Config{pager}
69893cff
RGS
1119
1120 # If not, fall back to 'more'.
e22ea7cc
RF
1121 : 'more'
1122 )
1123 unless defined $pager;
69893cff
RGS
1124
1125=pod
1126
1127We set up the command to be used to access the man pages, the command
be9a9b1d
AT
1128recall character (C<!> unless otherwise defined) and the shell escape
1129character (C<!> unless otherwise defined). Yes, these do conflict, and
69893cff
RGS
1130neither works in the debugger at the moment.
1131
1132=cut
1133
055fd3a9 1134setman();
69893cff
RGS
1135
1136# Set up defaults for command recall and shell escape (note:
1137# these currently don't work in linemode debugging).
2218c045
SF
1138recallCommand("!") unless defined $prc;
1139shellBang("!") unless defined $psh;
69893cff
RGS
1140
1141=pod
1142
1143We then set up the gigantic string containing the debugger help.
1144We also set the limit on the number of arguments we'll display during a
1145trace.
1146
1147=cut
1148
04e43a21 1149sethelp();
69893cff
RGS
1150
1151# If we didn't get a default for the length of eval/stack trace args,
1152# set it here.
1d06cb2d 1153$maxtrace = 400 unless defined $maxtrace;
69893cff
RGS
1154
1155=head2 SETTING UP THE DEBUGGER GREETING
1156
be9a9b1d 1157The debugger I<greeting> helps to inform the user how many debuggers are
69893cff
RGS
1158running, and whether the current debugger is the primary or a child.
1159
1160If we are the primary, we just hang onto our pid so we'll have it when
1161or if we start a child debugger. If we are a child, we'll set things up
1162so we'll have a unique greeting and so the parent will give us our own
1163TTY later.
1164
1165We save the current contents of the C<PERLDB_PIDS> environment variable
1166because we mess around with it. We'll also need to hang onto it because
1167we'll need it if we restart.
1168
1169Child debuggers make a label out of the current PID structure recorded in
1170PERLDB_PIDS plus the new PID. They also mark themselves as not having a TTY
1171yet so the parent will give them one later via C<resetterm()>.
1172
1173=cut
1174
e22ea7cc 1175# Save the current contents of the environment; we're about to
69893cff 1176# much with it. We'll need this if we have to restart.
6b24a4b7 1177use vars qw($ini_pids);
f1583d8f 1178$ini_pids = $ENV{PERLDB_PIDS};
69893cff 1179
6b24a4b7
SF
1180use vars qw ($pids $term_pid);
1181
e22ea7cc
RF
1182if ( defined $ENV{PERLDB_PIDS} ) {
1183
69893cff 1184 # We're a child. Make us a label out of the current PID structure
e22ea7cc 1185 # recorded in PERLDB_PIDS plus our (new) PID. Mark us as not having
69893cff 1186 # a term yet so the parent will give us one later via resetterm().
55f4245e
JM
1187
1188 my $env_pids = $ENV{PERLDB_PIDS};
1189 $pids = "[$env_pids]";
1190
1191 # Unless we are on OpenVMS, all programs under the DCL shell run under
1192 # the same PID.
1193
1194 if (($^O eq 'VMS') && ($env_pids =~ /\b$$\b/)) {
1195 $term_pid = $$;
1196 }
1197 else {
1198 $ENV{PERLDB_PIDS} .= "->$$";
1199 $term_pid = -1;
1200 }
1201
69893cff
RGS
1202} ## end if (defined $ENV{PERLDB_PIDS...
1203else {
e22ea7cc
RF
1204
1205 # We're the parent PID. Initialize PERLDB_PID in case we end up with a
69893cff
RGS
1206 # child debugger, and mark us as the parent, so we'll know to set up
1207 # more TTY's is we have to.
1208 $ENV{PERLDB_PIDS} = "$$";
619a0444 1209 $pids = "[pid=$$]";
e22ea7cc 1210 $term_pid = $$;
f1583d8f 1211}
69893cff 1212
6b24a4b7 1213use vars qw($pidprompt);
f1583d8f 1214$pidprompt = '';
69893cff
RGS
1215
1216# Sets up $emacs as a synonym for $slave_editor.
7793e5c2 1217our ($slave_editor);
69893cff
RGS
1218*emacs = $slave_editor if $slave_editor; # May be used in afterinit()...
1219
1220=head2 READING THE RC FILE
1221
b570d64b 1222The debugger will read a file of initialization options if supplied. If
69893cff
RGS
1223running interactively, this is C<.perldb>; if not, it's C<perldb.ini>.
1224
b570d64b 1225=cut
69893cff
RGS
1226
1227# As noted, this test really doesn't check accurately that the debugger
1228# is running at a terminal or not.
d338d6fe 1229
6b24a4b7 1230use vars qw($rcfile);
fb4d8a6c
SF
1231{
1232 my $dev_tty = (($^O eq 'VMS') ? 'TT:' : '/dev/tty');
1233 # this is the wrong metric!
1234 $rcfile = ((-e $dev_tty) ? ".perldb" : "perldb.ini");
d338d6fe
PP
1235}
1236
69893cff
RGS
1237=pod
1238
1239The debugger does a safety test of the file to be read. It must be owned
1240either by the current user or root, and must only be writable by the owner.
1241
1242=cut
1243
1244# This wraps a safety test around "do" to read and evaluate the init file.
1245#
055fd3a9
GS
1246# This isn't really safe, because there's a race
1247# between checking and opening. The solution is to
1248# open and fstat the handle, but then you have to read and
1249# eval the contents. But then the silly thing gets
69893cff
RGS
1250# your lexical scope, which is unfortunate at best.
1251sub safe_do {
055fd3a9
GS
1252 my $file = shift;
1253
1254 # Just exactly what part of the word "CORE::" don't you understand?
69893cff
RGS
1255 local $SIG{__WARN__};
1256 local $SIG{__DIE__};
055fd3a9 1257
e22ea7cc 1258 unless ( is_safe_file($file) ) {
69893cff 1259 CORE::warn <<EO_GRIPE;
055fd3a9 1260perldb: Must not source insecure rcfile $file.
b570d64b 1261 You or the superuser must be the owner, and it must not
69893cff 1262 be writable by anyone but its owner.
055fd3a9 1263EO_GRIPE
69893cff
RGS
1264 return;
1265 } ## end unless (is_safe_file($file...
055fd3a9
GS
1266
1267 do $file;
1268 CORE::warn("perldb: couldn't parse $file: $@") if $@;
69893cff 1269} ## end sub safe_do
055fd3a9 1270
69893cff
RGS
1271# This is the safety test itself.
1272#
055fd3a9
GS
1273# Verifies that owner is either real user or superuser and that no
1274# one but owner may write to it. This function is of limited use
1275# when called on a path instead of upon a handle, because there are
1276# no guarantees that filename (by dirent) whose file (by ino) is
e22ea7cc 1277# eventually accessed is the same as the one tested.
055fd3a9
GS
1278# Assumes that the file's existence is not in doubt.
1279sub is_safe_file {
1280 my $path = shift;
69893cff 1281 stat($path) || return; # mysteriously vaporized
e22ea7cc 1282 my ( $dev, $ino, $mode, $nlink, $uid, $gid ) = stat(_);
055fd3a9
GS
1283
1284 return 0 if $uid != 0 && $uid != $<;
1285 return 0 if $mode & 022;
1286 return 1;
69893cff 1287} ## end sub is_safe_file
055fd3a9 1288
69893cff 1289# If the rcfile (whichever one we decided was the right one to read)
e22ea7cc
RF
1290# exists, we safely do it.
1291if ( -f $rcfile ) {
055fd3a9 1292 safe_do("./$rcfile");
69893cff 1293}
e22ea7cc 1294
69893cff 1295# If there isn't one here, try the user's home directory.
e22ea7cc 1296elsif ( defined $ENV{HOME} && -f "$ENV{HOME}/$rcfile" ) {
055fd3a9
GS
1297 safe_do("$ENV{HOME}/$rcfile");
1298}
e22ea7cc 1299
69893cff 1300# Else try the login directory.
e22ea7cc 1301elsif ( defined $ENV{LOGDIR} && -f "$ENV{LOGDIR}/$rcfile" ) {
055fd3a9 1302 safe_do("$ENV{LOGDIR}/$rcfile");
d338d6fe
PP
1303}
1304
69893cff 1305# If the PERLDB_OPTS variable has options in it, parse those out next.
e22ea7cc
RF
1306if ( defined $ENV{PERLDB_OPTS} ) {
1307 parse_options( $ENV{PERLDB_OPTS} );
d338d6fe
PP
1308}
1309
69893cff
RGS
1310=pod
1311
1312The last thing we do during initialization is determine which subroutine is
1313to be used to obtain a new terminal when a new debugger is started. Right now,
b0b54b5e 1314the debugger only handles TCP sockets, X11, OS/2, amd Mac OS X
11653f7f 1315(darwin).
69893cff
RGS
1316
1317=cut
1318
1319# Set up the get_fork_TTY subroutine to be aliased to the proper routine.
1320# Works if you're running an xterm or xterm-like window, or you're on
6fae1ad7
RF
1321# OS/2, or on Mac OS X. This may need some expansion.
1322
1323if (not defined &get_fork_TTY) # only if no routine exists
69893cff 1324{
b570d64b 1325 if ( defined $remoteport ) {
11653f7f
JJ
1326 # Expect an inetd-like server
1327 *get_fork_TTY = \&socket_get_fork_TTY; # to listen to us
1328 }
1329 elsif (defined $ENV{TERM} # If we know what kind
6fae1ad7
RF
1330 # of terminal this is,
1331 and $ENV{TERM} eq 'xterm' # and it's an xterm,
1332 and defined $ENV{DISPLAY} # and what display it's on,
1333 )
1334 {
1335 *get_fork_TTY = \&xterm_get_fork_TTY; # use the xterm version
1336 }
1337 elsif ( $^O eq 'os2' ) { # If this is OS/2,
1338 *get_fork_TTY = \&os2_get_fork_TTY; # use the OS/2 version
1339 }
1340 elsif ( $^O eq 'darwin' # If this is Mac OS X
1341 and defined $ENV{TERM_PROGRAM} # and we're running inside
1342 and $ENV{TERM_PROGRAM}
1343 eq 'Apple_Terminal' # Terminal.app
1344 )
1345 {
1346 *get_fork_TTY = \&macosx_get_fork_TTY; # use the Mac OS X version
1347 }
69893cff 1348} ## end if (not defined &get_fork_TTY...
e22ea7cc 1349
dbb46cec
DQ
1350# untaint $^O, which may have been tainted by the last statement.
1351# see bug [perl #24674]
e22ea7cc
RF
1352$^O =~ m/^(.*)\z/;
1353$^O = $1;
f1583d8f 1354
d12a4851 1355# Here begin the unreadable code. It needs fixing.
055fd3a9 1356
69893cff
RGS
1357=head2 RESTART PROCESSING
1358
1359This section handles the restart command. When the C<R> command is invoked, it
1360tries to capture all of the state it can into environment variables, and
1361then sets C<PERLDB_RESTART>. When we start executing again, we check to see
1362if C<PERLDB_RESTART> is there; if so, we reload all the information that
1363the R command stuffed into the environment variables.
1364
b570d64b 1365 PERLDB_RESTART - flag only, contains no restart data itself.
69893cff
RGS
1366 PERLDB_HIST - command history, if it's available
1367 PERLDB_ON_LOAD - breakpoints set by the rc file
1368 PERLDB_POSTPONE - subs that have been loaded/not executed, and have actions
1369 PERLDB_VISITED - files that had breakpoints
1370 PERLDB_FILE_... - breakpoints for a file
1371 PERLDB_OPT - active options
1372 PERLDB_INC - the original @INC
1373 PERLDB_PRETYPE - preprompt debugger actions
1374 PERLDB_PRE - preprompt Perl code
1375 PERLDB_POST - post-prompt Perl code
1376 PERLDB_TYPEAHEAD - typeahead captured by readline()
1377
1378We chug through all these variables and plug the values saved in them
1379back into the appropriate spots in the debugger.
1380
1381=cut
1382
6b24a4b7
SF
1383use vars qw(@hist @truehist %postponed_file @typeahead);
1384
fb0fb5f4
SF
1385sub _restore_shared_globals_after_restart
1386{
1387 @hist = get_list('PERLDB_HIST');
1388 %break_on_load = get_list("PERLDB_ON_LOAD");
1389 %postponed = get_list("PERLDB_POSTPONE");
1390
1391 share(@hist);
1392 share(@truehist);
1393 share(%break_on_load);
1394 share(%postponed);
1395}
1396
e18a02a6 1397sub _restore_breakpoints_and_actions {
e22ea7cc 1398
e22ea7cc 1399 my @had_breakpoints = get_list("PERLDB_VISITED");
e18a02a6 1400
bdba49ad
SF
1401 for my $file_idx ( 0 .. $#had_breakpoints ) {
1402 my $filename = $had_breakpoints[$file_idx];
1403 my %pf = get_list("PERLDB_FILE_$file_idx");
1404 $postponed_file{ $filename } = \%pf if %pf;
1405 my @lines = sort {$a <=> $b} keys(%pf);
1406 my @enabled_statuses = get_list("PERLDB_FILE_ENABLED_$file_idx");
1407 for my $line_idx (0 .. $#lines) {
1408 _set_breakpoint_enabled_status(
1409 $filename,
1410 $lines[$line_idx],
1411 ($enabled_statuses[$line_idx] ? 1 : ''),
1412 );
1413 }
e22ea7cc 1414 }
69893cff 1415
e18a02a6
SF
1416 return;
1417}
1418
ca50076b
SF
1419sub _restore_options_after_restart
1420{
1421 my %options_map = get_list("PERLDB_OPT");
1422
1423 while ( my ( $opt, $val ) = each %options_map ) {
1424 $val =~ s/[\\\']/\\$1/g;
1425 parse_options("$opt'$val'");
1426 }
1427
1428 return;
1429}
1430
18580168
SF
1431sub _restore_globals_after_restart
1432{
1433 # restore original @INC
1434 @INC = get_list("PERLDB_INC");
1435 @ini_INC = @INC;
1436
1437 # return pre/postprompt actions and typeahead buffer
1438 $pretype = [ get_list("PERLDB_PRETYPE") ];
1439 $pre = [ get_list("PERLDB_PRE") ];
1440 $post = [ get_list("PERLDB_POST") ];
1441 @typeahead = get_list( "PERLDB_TYPEAHEAD", @typeahead );
1442
1443 return;
1444}
1445
fb0fb5f4 1446
e18a02a6
SF
1447if ( exists $ENV{PERLDB_RESTART} ) {
1448
1449 # We're restarting, so we don't need the flag that says to restart anymore.
1450 delete $ENV{PERLDB_RESTART};
1451
1452 # $restart = 1;
fb0fb5f4 1453 _restore_shared_globals_after_restart();
e18a02a6
SF
1454
1455 _restore_breakpoints_and_actions();
1456
69893cff 1457 # restore options
ca50076b 1458 _restore_options_after_restart();
69893cff 1459
18580168 1460 _restore_globals_after_restart();
69893cff
RGS
1461} ## end if (exists $ENV{PERLDB_RESTART...
1462
1463=head2 SETTING UP THE TERMINAL
1464
1465Now, we'll decide how the debugger is going to interact with the user.
1466If there's no TTY, we set the debugger to run non-stop; there's not going
1467to be anyone there to enter commands.
1468
1469=cut
54d04a52 1470
ebd0282e 1471use vars qw($notty $console $tty $LINEINFO);
6b24a4b7
SF
1472use vars qw($lineinfo $doccmd);
1473
ebd0282e
SF
1474our ($runnonstop);
1475
d338d6fe 1476if ($notty) {
69893cff 1477 $runnonstop = 1;
2dbd01ad 1478 share($runnonstop);
69893cff 1479}
d12a4851 1480
69893cff
RGS
1481=pod
1482
1483If there is a TTY, we have to determine who it belongs to before we can
1484proceed. If this is a slave editor or graphical debugger (denoted by
1485the first command-line switch being '-emacs'), we shift this off and
1486set C<$rl> to 0 (XXX ostensibly to do straight reads).
1487
1488=cut
1489
1490else {
e22ea7cc 1491
69893cff
RGS
1492 # Is Perl being run from a slave editor or graphical debugger?
1493 # If so, don't use readline, and set $slave_editor = 1.
2b0b9dd1
SF
1494 if ($slave_editor = ( @main::ARGV && ( $main::ARGV[0] eq '-emacs' ) )) {
1495 $rl = 0;
1496 shift(@main::ARGV);
1497 }
e22ea7cc
RF
1498
1499 #require Term::ReadLine;
d12a4851 1500
69893cff
RGS
1501=pod
1502
1503We then determine what the console should be on various systems:
1504
1505=over 4
1506
1507=item * Cygwin - We use C<stdin> instead of a separate device.
1508
1509=cut
1510
e22ea7cc
RF
1511 if ( $^O eq 'cygwin' ) {
1512
69893cff
RGS
1513 # /dev/tty is binary. use stdin for textmode
1514 undef $console;
1515 }
1516
1517=item * Unix - use C</dev/tty>.
1518
1519=cut
1520
e22ea7cc 1521 elsif ( -e "/dev/tty" ) {
69893cff
RGS
1522 $console = "/dev/tty";
1523 }
1524
1525=item * Windows or MSDOS - use C<con>.
1526
1527=cut
1528
e22ea7cc 1529 elsif ( $^O eq 'dos' or -e "con" or $^O eq 'MSWin32' ) {
69893cff
RGS
1530 $console = "con";
1531 }
1532
69893cff
RGS
1533=item * VMS - use C<sys$command>.
1534
1535=cut
1536
1537 else {
e22ea7cc 1538
69893cff
RGS
1539 # everything else is ...
1540 $console = "sys\$command";
d12a4851 1541 }
69893cff
RGS
1542
1543=pod
1544
1545=back
1546
1547Several other systems don't use a specific console. We C<undef $console>
1548for those (Windows using a slave editor/graphical debugger, NetWare, OS/2
1549with a slave editor, Epoc).
1550
1551=cut
d12a4851 1552
e22ea7cc
RF
1553 if ( ( $^O eq 'MSWin32' ) and ( $slave_editor or defined $ENV{EMACS} ) ) {
1554
69893cff 1555 # /dev/tty is binary. use stdin for textmode
e22ea7cc
RF
1556 $console = undef;
1557 }
1558
1559 if ( $^O eq 'NetWare' ) {
d12a4851 1560
69893cff
RGS
1561 # /dev/tty is binary. use stdin for textmode
1562 $console = undef;
1563 }
d12a4851 1564
69893cff
RGS
1565 # In OS/2, we need to use STDIN to get textmode too, even though
1566 # it pretty much looks like Unix otherwise.
e22ea7cc
RF
1567 if ( defined $ENV{OS2_SHELL} and ( $slave_editor or $ENV{WINDOWID} ) )
1568 { # In OS/2
1569 $console = undef;
1570 }
1571
1572 # EPOC also falls into the 'got to use STDIN' camp.
1573 if ( $^O eq 'epoc' ) {
1574 $console = undef;
1575 }
d12a4851 1576
69893cff
RGS
1577=pod
1578
1579If there is a TTY hanging around from a parent, we use that as the console.
1580
1581=cut
1582
e22ea7cc 1583 $console = $tty if defined $tty;
d12a4851 1584
b570d64b 1585=head2 SOCKET HANDLING
69893cff
RGS
1586
1587The debugger is capable of opening a socket and carrying out a debugging
1588session over the socket.
1589
1590If C<RemotePort> was defined in the options, the debugger assumes that it
1591should try to start a debugging session on that port. It builds the socket
1592and then tries to connect the input and output filehandles to it.
1593
1594=cut
1595
1596 # Handle socket stuff.
e22ea7cc
RF
1597
1598 if ( defined $remoteport ) {
1599
69893cff
RGS
1600 # If RemotePort was defined in the options, connect input and output
1601 # to the socket.
11653f7f 1602 $IN = $OUT = connect_remoteport();
69893cff
RGS
1603 } ## end if (defined $remoteport)
1604
1605=pod
1606
1607If no C<RemotePort> was defined, and we want to create a TTY on startup,
1608this is probably a situation where multiple debuggers are running (for example,
1609a backticked command that starts up another debugger). We create a new IN and
1610OUT filehandle, and do the necessary mojo to create a new TTY if we know how
1611and if we can.
1612
1613=cut
1614
1615 # Non-socket.
1616 else {
e22ea7cc 1617
69893cff
RGS
1618 # Two debuggers running (probably a system or a backtick that invokes
1619 # the debugger itself under the running one). create a new IN and OUT
e22ea7cc 1620 # filehandle, and do the necessary mojo to create a new tty if we
69893cff 1621 # know how, and we can.
e22ea7cc
RF
1622 create_IN_OUT(4) if $CreateTTY & 4;
1623 if ($console) {
1624
69893cff 1625 # If we have a console, check to see if there are separate ins and
cd1191f1 1626 # outs to open. (They are assumed identical if not.)
69893cff 1627
e22ea7cc
RF
1628 my ( $i, $o ) = split /,/, $console;
1629 $o = $i unless defined $o;
69893cff 1630
69893cff 1631 # read/write on in, or just read, or read on STDIN.
e22ea7cc
RF
1632 open( IN, "+<$i" )
1633 || open( IN, "<$i" )
1634 || open( IN, "<&STDIN" );
1635
69893cff
RGS
1636 # read/write/create/clobber out, or write/create/clobber out,
1637 # or merge with STDERR, or merge with STDOUT.
e22ea7cc
RF
1638 open( OUT, "+>$o" )
1639 || open( OUT, ">$o" )
1640 || open( OUT, ">&STDERR" )
1641 || open( OUT, ">&STDOUT" ); # so we don't dongle stdout
1642
1643 } ## end if ($console)
1644 elsif ( not defined $console ) {
1645
1646 # No console. Open STDIN.
1647 open( IN, "<&STDIN" );
1648
1649 # merge with STDERR, or with STDOUT.
1650 open( OUT, ">&STDERR" )
1651 || open( OUT, ">&STDOUT" ); # so we don't dongle stdout
1652 $console = 'STDIN/OUT';
69893cff
RGS
1653 } ## end elsif (not defined $console)
1654
1655 # Keep copies of the filehandles so that when the pager runs, it
1656 # can close standard input without clobbering ours.
2b0b9dd1
SF
1657 if ($console or (not defined($console))) {
1658 $IN = \*IN;
1659 $OUT = \*OUT;
1660 }
e22ea7cc
RF
1661 } ## end elsif (from if(defined $remoteport))
1662
1663 # Unbuffer DB::OUT. We need to see responses right away.
70c9432b 1664 $OUT->autoflush(1);
e22ea7cc
RF
1665
1666 # Line info goes to debugger output unless pointed elsewhere.
1667 # Pointing elsewhere makes it possible for slave editors to
1668 # keep track of file and position. We have both a filehandle
1669 # and a I/O description to keep track of.
1670 $LINEINFO = $OUT unless defined $LINEINFO;
1671 $lineinfo = $console unless defined $lineinfo;
2dbd01ad
SF
1672 # share($LINEINFO); # <- unable to share globs
1673 share($lineinfo); #
e22ea7cc 1674
69893cff
RGS
1675=pod
1676
1677To finish initialization, we show the debugger greeting,
1678and then call the C<afterinit()> subroutine if there is one.
1679
1680=cut
d12a4851 1681
e22ea7cc
RF
1682 # Show the debugger greeting.
1683 $header =~ s/.Header: ([^,]+),v(\s+\S+\s+\S+).*$/$1$2/;
1684 unless ($runnonstop) {
1685 local $\ = '';
1686 local $, = '';
1687 if ( $term_pid eq '-1' ) {
1688 print $OUT "\nDaughter DB session started...\n";
1689 }
1690 else {
1691 print $OUT "\nLoading DB routines from $header\n";
1692 print $OUT (
1693 "Editor support ",
1694 $slave_editor ? "enabled" : "available", ".\n"
1695 );
1696 print $OUT
1f874cb6 1697"\nEnter h or 'h h' for help, or '$doccmd perldebug' for more help.\n\n";
69893cff
RGS
1698 } ## end else [ if ($term_pid eq '-1')
1699 } ## end unless ($runnonstop)
1700} ## end else [ if ($notty)
1701
1702# XXX This looks like a bug to me.
1703# Why copy to @ARGS and then futz with @args?
d338d6fe 1704@ARGS = @ARGV;
6b24a4b7 1705# for (@args) {
69893cff
RGS
1706 # Make sure backslashes before single quotes are stripped out, and
1707 # keep args unless they are numeric (XXX why?)
e22ea7cc
RF
1708 # s/\'/\\\'/g; # removed while not justified understandably
1709 # s/(.*)/'$1'/ unless /^-?[\d.]+$/; # ditto
6b24a4b7 1710# }
d338d6fe 1711
e22ea7cc 1712# If there was an afterinit() sub defined, call it. It will get
69893cff 1713# executed in our scope, so it can fiddle with debugger globals.
e22ea7cc 1714if ( defined &afterinit ) { # May be defined in $rcfile
2b0b9dd1 1715 afterinit();
d338d6fe 1716}
e22ea7cc 1717
69893cff 1718# Inform us about "Stack dump during die enabled ..." in dieLevel().
6b24a4b7
SF
1719use vars qw($I_m_init);
1720
43aed9ee
IZ
1721$I_m_init = 1;
1722
d338d6fe
PP
1723############################################################ Subroutines
1724
69893cff
RGS
1725=head1 SUBROUTINES
1726
1727=head2 DB
1728
1729This gigantic subroutine is the heart of the debugger. Called before every
1730statement, its job is to determine if a breakpoint has been reached, and
1731stop if so; read commands from the user, parse them, and execute
b468dcb6 1732them, and then send execution off to the next statement.
69893cff
RGS
1733
1734Note that the order in which the commands are processed is very important;
1735some commands earlier in the loop will actually alter the C<$cmd> variable
be9a9b1d 1736to create other commands to be executed later. This is all highly I<optimized>
69893cff
RGS
1737but can be confusing. Check the comments for each C<$cmd ... && do {}> to
1738see what's happening in any given command.
1739
1740=cut
1741
6b24a4b7
SF
1742use vars qw(
1743 $action
1744 %alias
1745 $cmd
6b24a4b7
SF
1746 $fall_off_end
1747 $file
1748 $filename_ini
1749 $finished
1750 %had_breakpoints
1751 $incr
1752 $laststep
1753 $level
1754 $max
6b24a4b7
SF
1755 $package
1756 $rc
1757 $sh
6b24a4b7 1758 $try
2c247e84 1759 $end
6b24a4b7
SF
1760);
1761
1ce985d2
SF
1762our (
1763 $doret,
1764 $stack_depth,
1765 @stack,
1766 @to_watch,
1767 @old_watch,
1768);
8ad70697 1769
6791e41b
SF
1770sub _DB__determine_if_we_should_break
1771{
1772 # if we have something here, see if we should break.
1773 # $stop is lexical and local to this block - $action on the other hand
1774 # is global.
1775 my $stop;
1776
1777 if ( $dbline{$line}
1778 && _is_breakpoint_enabled($filename, $line)
1779 && (( $stop, $action ) = split( /\0/, $dbline{$line} ) ) )
1780 {
1781
1782 # Stop if the stop criterion says to just stop.
1783 if ( $stop eq '1' ) {
1784 $signal |= 1;
1785 }
1786
1787 # It's a conditional stop; eval it in the user's context and
1788 # see if we should stop. If so, remove the one-time sigil.
1789 elsif ($stop) {
1790 $evalarg = "\$DB::signal |= 1 if do {$stop}";
1791 &eval;
1792 # If the breakpoint is temporary, then delete its enabled status.
1793 if ($dbline{$line} =~ s/;9($|\0)/$1/) {
1794 _cancel_breakpoint_temp_enabled_status($filename, $line);
1795 }
1796 }
1797 } ## end if ($dbline{$line} && ...
1798}
1799
8481f647
SF
1800sub _DB__is_finished {
1801 if ($finished and $level <= 1) {
1802 end_report();
1803 return 1;
1804 }
1805 else {
1806 return;
1807 }
1808}
1809
32bbadc6
SF
1810sub _DB__read_next_cmd
1811{
1812 my ($tid) = @_;
1813
1814 # We have a terminal, or can get one ...
1815 if (!$term) {
1816 setterm();
1817 }
1818
1819 # ... and it belogs to this PID or we get one for this PID ...
1820 if ($term_pid != $$) {
1821 resetterm(1);
1822 }
1823
1824 # ... and we got a line of command input ...
1825 $cmd = DB::readline(
1826 "$pidprompt $tid DB"
1827 . ( '<' x $level )
1828 . ( $#hist + 1 )
1829 . ( '>' x $level ) . " "
1830 );
1831
1832 return defined($cmd);
1833}
1834
7013f40c
SF
1835sub _DB__trim_command_and_return_first_component {
1836 $cmd =~ s/\A\s+//s; # trim annoying leading whitespace
1837 $cmd =~ s/\s+\z//s; # trim annoying trailing whitespace
1838
1839 $cmd =~ m{\A(\S*)};
1840 return $1;
1841}
1842
2a802473
SF
1843sub _DB__handle_f_command {
1844 if (($file) = $cmd =~ /\Af\b\s*(.*)/) {
1845 $file =~ s/\s+$//;
1846
1847 # help for no arguments (old-style was return from sub).
1848 if ( !$file ) {
1849 print $OUT
1850 "The old f command is now the r command.\n"; # hint
1851 print $OUT "The new f command switches filenames.\n";
1852 next CMD;
1853 } ## end if (!$file)
1854
1855 # if not in magic file list, try a close match.
1856 if ( !defined $main::{ '_<' . $file } ) {
1857 if ( ($try) = grep( m#^_<.*$file#, keys %main:: ) ) {
1858 {
1859 $try = substr( $try, 2 );
1860 print $OUT "Choosing $try matching '$file':\n";
1861 $file = $try;
1862 }
1863 } ## end if (($try) = grep(m#^_<.*$file#...
1864 } ## end if (!defined $main::{ ...
1865
1866 # If not successfully switched now, we failed.
1867 if ( !defined $main::{ '_<' . $file } ) {
1868 print $OUT "No file matching '$file' is loaded.\n";
1869 next CMD;
1870 }
1871
1872 # We switched, so switch the debugger internals around.
1873 elsif ( $file ne $filename ) {
1874 *dbline = $main::{ '_<' . $file };
1875 $max = $#dbline;
1876 $filename = $file;
1877 $start = 1;
1878 $cmd = "l";
1879 } ## end elsif ($file ne $filename)
1880
1881 # We didn't switch; say we didn't.
1882 else {
1883 print $OUT "Already in $file.\n";
1884 next CMD;
1885 }
1886 }
1887
1888 return;
1889}
1890
6115a173
SF
1891sub _DB__handle_dot_command {
1892 my ($obj) = @_;
1893
1894 # . command.
1895 if ($cmd eq '.') {
1896 $incr = -1; # stay at current line
1897
1898 # Reset everything to the old location.
1899 $start = $line;
1900 $filename = $filename_ini;
1901 *dbline = $main::{ '_<' . $filename };
1902 $max = $#dbline;
1903
1904 # Now where are we?
1905 print_lineinfo($obj->position());
1906 next CMD;
1907 }
1908
1909 return;
1910}
1911
2b0b9dd1
SF
1912sub DB {
1913
1914 # lock the debugger and get the thread id for the prompt
1915 lock($DBGR);
1916 my $tid;
1917 my $position;
1918 my ($prefix, $after, $infix);
1919 my $pat;
22fc883d 1920 my $explicit_stop;
2b0b9dd1
SF
1921
1922 if ($ENV{PERL5DB_THREADED}) {
1923 $tid = eval { "[".threads->tid."]" };
1924 }
1925
22fc883d
SF
1926 my $obj = DB::Obj->new(
1927 {
1928 position => \$position,
1929 prefix => \$prefix,
1930 after => \$after,
1931 explicit_stop => \$explicit_stop,
1932 infix => \$infix,
1933 },
1934 );
1935
1936 $obj->_DB_on_init__initialize_globals(@_);
2b0b9dd1 1937
69893cff
RGS
1938 # Preserve current values of $@, $!, $^E, $,, $/, $\, $^W.
1939 # The code being debugged may have altered them.
d338d6fe 1940 &save;
69893cff
RGS
1941
1942 # Since DB::DB gets called after every line, we can use caller() to
1943 # figure out where we last were executing. Sneaky, eh? This works because
e22ea7cc 1944 # caller is returning all the extra information when called from the
69893cff 1945 # debugger.
e22ea7cc 1946 local ( $package, $filename, $line ) = caller;
6b24a4b7 1947 $filename_ini = $filename;
69893cff
RGS
1948
1949 # set up the context for DB::eval, so it can properly execute
1950 # code on behalf of the user. We add the package in so that the
1951 # code is eval'ed in the proper package (not in the debugger!).
6b24a4b7 1952 local $usercontext = _calc_usercontext($package);
69893cff
RGS
1953
1954 # Create an alias to the active file magical array to simplify
1955 # the code here.
e22ea7cc 1956 local (*dbline) = $main::{ '_<' . $filename };
aa057b67 1957
69893cff 1958 # Last line in the program.
55783941 1959 $max = $#dbline;
69893cff 1960
22fc883d 1961 _DB__determine_if_we_should_break(@_);
69893cff
RGS
1962
1963 # Preserve the current stop-or-not, and see if any of the W
1964 # (watch expressions) has changed.
36477c24 1965 my $was_signal = $signal;
69893cff
RGS
1966
1967 # If we have any watch expressions ...
22fc883d 1968 $obj->_DB__handle_watch_expressions(@_);
69893cff
RGS
1969
1970=head2 C<watchfunction()>
1971
1972C<watchfunction()> is a function that can be defined by the user; it is a
b570d64b 1973function which will be run on each entry to C<DB::DB>; it gets the
69893cff
RGS
1974current package, filename, and line as its parameters.
1975
b570d64b 1976The watchfunction can do anything it likes; it is executing in the
69893cff
RGS
1977debugger's context, so it has access to all of the debugger's internal
1978data structures and functions.
1979
1980C<watchfunction()> can control the debugger's actions. Any of the following
1981will cause the debugger to return control to the user's program after
1982C<watchfunction()> executes:
1983
b570d64b 1984=over 4
69893cff 1985
be9a9b1d
AT
1986=item *
1987
1988Returning a false value from the C<watchfunction()> itself.
1989
1990=item *
1991
1992Altering C<$single> to a false value.
1993
1994=item *
69893cff 1995
be9a9b1d 1996Altering C<$signal> to a false value.
69893cff 1997
be9a9b1d 1998=item *
69893cff 1999
be9a9b1d 2000Turning off the C<4> bit in C<$trace> (this also disables the
69893cff
RGS
2001check for C<watchfunction()>. This can be done with
2002
2003 $trace &= ~4;
2004
2005=back
2006
2007=cut
2008
e22ea7cc 2009 # If there's a user-defined DB::watchfunction, call it with the
69893cff
RGS
2010 # current package, filename, and line. The function executes in
2011 # the DB:: package.
e22ea7cc
RF
2012 if ( $trace & 4 ) { # User-installed watch
2013 return
2014 if watchfunction( $package, $filename, $line )
2015 and not $single
2016 and not $was_signal
2017 and not( $trace & ~4 );
69893cff
RGS
2018 } ## end if ($trace & 4)
2019
e22ea7cc 2020 # Pick up any alteration to $signal in the watchfunction, and
69893cff 2021 # turn off the signal now.
6027b9a3 2022 $was_signal = $signal;
69893cff
RGS
2023 $signal = 0;
2024
2025=head2 GETTING READY TO EXECUTE COMMANDS
2026
2027The debugger decides to take control if single-step mode is on, the
2028C<t> command was entered, or the user generated a signal. If the program
2029has fallen off the end, we set things up so that entering further commands
2030won't cause trouble, and we say that the program is over.
2031
2032=cut
2033
8dc67a69
SF
2034 # Make sure that we always print if asked for explicitly regardless
2035 # of $trace_to_depth .
22fc883d 2036 $explicit_stop = ($single || $was_signal);
8dc67a69 2037
69893cff
RGS
2038 # Check to see if we should grab control ($single true,
2039 # trace set appropriately, or we got a signal).
8dc67a69 2040 if ( $explicit_stop || ( $trace & 1 ) ) {
22fc883d 2041 $obj->_DB__grab_control(@_);
69893cff
RGS
2042 } ## end if ($single || ($trace...
2043
2044=pod
2045
2046If there's an action to be executed for the line we stopped at, execute it.
b570d64b 2047If there are any preprompt actions, execute those as well.
e219e2fb
RF
2048
2049=cut
2050
69893cff 2051 # If there's an action, do it now.
05da04df
SF
2052 if ($action) {
2053 $evalarg = $action;
2054 DB::eval();
2055 }
e219e2fb 2056
69893cff
RGS
2057 # Are we nested another level (e.g., did we evaluate a function
2058 # that had a breakpoint in it at the debugger prompt)?
e22ea7cc
RF
2059 if ( $single || $was_signal ) {
2060
69893cff 2061 # Yes, go down a level.
e22ea7cc 2062 local $level = $level + 1;
69893cff
RGS
2063
2064 # Do any pre-prompt actions.
e22ea7cc 2065 foreach $evalarg (@$pre) {
7c54f46a 2066 DB::eval();
e22ea7cc 2067 }
69893cff
RGS
2068
2069 # Complain about too much recursion if we passed the limit.
05da04df
SF
2070 if ($single & 4) {
2071 print $OUT $stack_depth . " levels deep in subroutine calls!\n";
2072 }
69893cff
RGS
2073
2074 # The line we're currently on. Set $incr to -1 to stay here
2075 # until we get a command that tells us to advance.
e22ea7cc
RF
2076 $start = $line;
2077 $incr = -1; # for backward motion.
69893cff
RGS
2078
2079 # Tack preprompt debugger actions ahead of any actual input.
e22ea7cc 2080 @typeahead = ( @$pretype, @typeahead );
69893cff
RGS
2081
2082=head2 WHERE ARE WE?
2083
2084XXX Relocate this section?
2085
2086The debugger normally shows the line corresponding to the current line of
2087execution. Sometimes, though, we want to see the next line, or to move elsewhere
2088in the file. This is done via the C<$incr>, C<$start>, and C<$max> variables.
2089
be9a9b1d
AT
2090C<$incr> controls by how many lines the I<current> line should move forward
2091after a command is executed. If set to -1, this indicates that the I<current>
69893cff
RGS
2092line shouldn't change.
2093
be9a9b1d 2094C<$start> is the I<current> line. It is used for things like knowing where to
69893cff
RGS
2095move forwards or backwards from when doing an C<L> or C<-> command.
2096
2097C<$max> tells the debugger where the last line of the current file is. It's
2098used to terminate loops most often.
2099
2100=head2 THE COMMAND LOOP
2101
2102Most of C<DB::DB> is actually a command parsing and dispatch loop. It comes
2103in two parts:
2104
2105=over 4
2106
be9a9b1d
AT
2107=item *
2108
2109The outer part of the loop, starting at the C<CMD> label. This loop
69893cff
RGS
2110reads a command and then executes it.
2111
be9a9b1d
AT
2112=item *
2113
2114The inner part of the loop, starting at the C<PIPE> label. This part
69893cff
RGS
2115is wholly contained inside the C<CMD> block and only executes a command.
2116Used to handle commands running inside a pager.
2117
2118=back
2119
2120So why have two labels to restart the loop? Because sometimes, it's easier to
2121have a command I<generate> another command and then re-execute the loop to do
2122the new command. This is faster, but perhaps a bit more convoluted.
2123
2124=cut
2125
2126 # The big command dispatch loop. It keeps running until the
2127 # user yields up control again.
2128 #
2129 # If we have a terminal for input, and we get something back
2130 # from readline(), keep on processing.
6b24a4b7
SF
2131 my $piped;
2132 my $selected;
2133
e22ea7cc 2134 CMD:
32bbadc6 2135 while (_DB__read_next_cmd($tid))
69893cff 2136 {
e22ea7cc 2137
8380a245 2138 share($cmd);
69893cff
RGS
2139 # ... try to execute the input as debugger commands.
2140
2141 # Don't stop running.
2142 $single = 0;
2143
2144 # No signal is active.
2145 $signal = 0;
2146
2147 # Handle continued commands (ending with \):
3d7a2a93 2148 if ($cmd =~ s/\\\z/\n/) {
eeb7da96 2149 $cmd .= DB::readline(" cont: ");
e22ea7cc 2150 redo CMD;
3d7a2a93 2151 }
69893cff
RGS
2152
2153=head4 The null command
2154
be9a9b1d 2155A newline entered by itself means I<re-execute the last command>. We grab the
69893cff
RGS
2156command out of C<$laststep> (where it was recorded previously), and copy it
2157back into C<$cmd> to be executed below. If there wasn't any previous command,
2158we'll do nothing below (no command will match). If there was, we also save it
2159in the command history and fall through to allow the command parsing to pick
2160it up.
2161
2162=cut
2163
2164 # Empty input means repeat the last command.
eeb7da96
SF
2165 if ($cmd eq '') {
2166 $cmd = $laststep;
2167 }
e22ea7cc 2168 chomp($cmd); # get rid of the annoying extra newline
eeb7da96
SF
2169 if (length($cmd) >= 2) {
2170 push( @hist, $cmd );
2171 }
e22ea7cc 2172 push( @truehist, $cmd );
2dbd01ad
SF
2173 share(@hist);
2174 share(@truehist);
e22ea7cc
RF
2175
2176 # This is a restart point for commands that didn't arrive
2177 # via direct user input. It allows us to 'redo PIPE' to
2178 # re-execute command processing without reading a new command.
69893cff 2179 PIPE: {
7013f40c 2180 my $i = _DB__trim_command_and_return_first_component();
69893cff
RGS
2181
2182=head3 COMMAND ALIASES
2183
2184The debugger can create aliases for commands (these are stored in the
2185C<%alias> hash). Before a command is executed, the command loop looks it up
2186in the alias hash and substitutes the contents of the alias for the command,
2187completely replacing it.
2188
2189=cut
2190
2191 # See if there's an alias for the command, and set it up if so.
e22ea7cc
RF
2192 if ( $alias{$i} ) {
2193
69893cff
RGS
2194 # Squelch signal handling; we want to keep control here
2195 # if something goes loco during the alias eval.
2196 local $SIG{__DIE__};
2197 local $SIG{__WARN__};
2198
2199 # This is a command, so we eval it in the DEBUGGER's
2200 # scope! Otherwise, we can't see the special debugger
2201 # variables, or get to the debugger's subs. (Well, we
2202 # _could_, but why make it even more complicated?)
2203 eval "\$cmd =~ $alias{$i}";
2204 if ($@) {
2205 local $\ = '';
1f874cb6 2206 print $OUT "Couldn't evaluate '$i' alias: $@";
69893cff
RGS
2207 next CMD;
2208 }
2209 } ## end if ($alias{$i})
2210
2211=head3 MAIN-LINE COMMANDS
2212
2213All of these commands work up to and after the program being debugged has
b570d64b 2214terminated.
69893cff
RGS
2215
2216=head4 C<q> - quit
2217
b570d64b 2218Quit the debugger. This entails setting the C<$fall_off_end> flag, so we don't
69893cff
RGS
2219try to execute further, cleaning any restart-related stuff out of the
2220environment, and executing with the last value of C<$?>.
2221
2222=cut
2223
3d7a2a93 2224 if ($cmd eq 'q') {
69893cff
RGS
2225 $fall_off_end = 1;
2226 clean_ENV();
2227 exit $?;
3d7a2a93 2228 }
69893cff 2229
611272bb 2230=head4 C<t> - trace [n]
69893cff
RGS
2231
2232Turn tracing on or off. Inverts the appropriate bit in C<$trace> (q.v.).
611272bb 2233If level is specified, set C<$trace_to_depth>.
69893cff
RGS
2234
2235=cut
2236
9d0b71b3 2237 $obj->_handle_t_command;
69893cff
RGS
2238
2239=head4 C<S> - list subroutines matching/not matching a pattern
2240
2241Walks through C<%sub>, checking to see whether or not to print the name.
2242
2243=cut
2244
9d0b71b3 2245 $obj->_handle_S_command;
69893cff
RGS
2246
2247=head4 C<X> - list variables in current package
2248
b570d64b 2249Since the C<V> command actually processes this, just change this to the
69893cff
RGS
2250appropriate C<V> command and fall through.
2251
69893cff
RGS
2252=head4 C<V> - list variables
2253
b570d64b 2254Uses C<dumpvar.pl> to dump out the current values for selected variables.
69893cff
RGS
2255
2256=cut
2257
1ce985d2 2258 $obj->_handle_V_command_and_X_command;
69893cff
RGS
2259
2260=head4 C<x> - evaluate and print an expression
2261
2262Hands the expression off to C<DB::eval>, setting it up to print the value
2263via C<dumpvar.pl> instead of just printing it directly.
2264
2265=cut
2266
826b9a2e 2267 if ($cmd =~ s#\Ax\b# #) { # Remainder gets done by DB::eval()
e22ea7cc 2268 $onetimeDump = 'dump'; # main::dumpvar shows the output
69893cff
RGS
2269
2270 # handle special "x 3 blah" syntax XXX propagate
2271 # doc back to special variables.
826b9a2e 2272 if ( $cmd =~ s#\A\s*(\d+)(?=\s)# #) {
e22ea7cc
RF
2273 $onetimedumpDepth = $1;
2274 }
826b9a2e 2275 }
69893cff
RGS
2276
2277=head4 C<m> - print methods
2278
2279Just uses C<DB::methods> to determine what methods are available.
2280
2281=cut
2282
826b9a2e 2283 if ($cmd =~ s#\Am\s+([\w:]+)\s*\z# #) {
e22ea7cc
RF
2284 methods($1);
2285 next CMD;
826b9a2e 2286 }
69893cff
RGS
2287
2288 # m expr - set up DB::eval to do the work
826b9a2e 2289 if ($cmd =~ s#\Am\b# #) { # Rest gets done by DB::eval()
e22ea7cc 2290 $onetimeDump = 'methods'; # method output gets used there
826b9a2e 2291 }
69893cff
RGS
2292
2293=head4 C<f> - switch files
2294
2295=cut
2296
2a802473 2297 _DB__handle_f_command();
69893cff
RGS
2298
2299=head4 C<.> - return to last-executed line.
2300
2301We set C<$incr> to -1 to indicate that the debugger shouldn't move ahead,
2302and then we look up the line in the magical C<%dbline> hash.
2303
2304=cut
2305
6115a173 2306 _DB__handle_dot_command($obj);
69893cff
RGS
2307
2308=head4 C<-> - back one window
2309
2310We change C<$start> to be one window back; if we go back past the first line,
2311we set it to be the first line. We ser C<$incr> to put us back at the
2312currently-executing line, and then put a C<l $start +> (list one window from
2313C<$start>) in C<$cmd> to be executed later.
2314
2315=cut
2316
2317 # - - back a window.
826b9a2e 2318 if ($cmd eq '-') {
e22ea7cc 2319
69893cff 2320 # back up by a window; go to 1 if back too far.
e22ea7cc
RF
2321 $start -= $incr + $window + 1;
2322 $start = 1 if $start <= 0;
2323 $incr = $window - 1;
69893cff
RGS
2324
2325 # Generate and execute a "l +" command (handled below).
e22ea7cc 2326 $cmd = 'l ' . ($start) . '+';
826b9a2e 2327 }
69893cff 2328
8481f647 2329=head3 PRE-580 COMMANDS VS. NEW COMMANDS: C<a, A, b, B, h, l, L, M, o, O, P, v, w, W, E<lt>, E<lt>E<lt>, E<0x7B>, E<0x7B>E<0x7B>>
69893cff
RGS
2330
2331In Perl 5.8.0, a realignment of the commands was done to fix up a number of
2332problems, most notably that the default case of several commands destroying
2333the user's work in setting watchpoints, actions, etc. We wanted, however, to
2334retain the old commands for those who were used to using them or who preferred
2335them. At this point, we check for the new commands and call C<cmd_wrapper> to
2336deal with them instead of processing them in-line.
2337
2338=cut
2339
2340 # All of these commands were remapped in perl 5.8.0;
e22ea7cc 2341 # we send them off to the secondary dispatcher (see below).
826b9a2e
SF
2342 if (my ($cmd_letter, $my_arg) = $cmd =~ /\A([aAbBeEhilLMoOPvwW]\b|[<>\{]{1,2})\s*(.*)/so) {
2343 &cmd_wrapper( $cmd_letter, $my_arg, $line );
e22ea7cc 2344 next CMD;
826b9a2e 2345 }
69893cff
RGS
2346
2347=head4 C<y> - List lexicals in higher scope
2348
826b9a2e 2349Uses C<PadWalker> to find the lexicals supplied as arguments in a scope
69893cff
RGS
2350above the current one and then displays then using C<dumpvar.pl>.
2351
2352=cut
2353
826b9a2e
SF
2354 if (my ($match_level, $match_vars)
2355 = $cmd =~ /^y(?:\s+(\d*)\s*(.*))?$/) {
69893cff
RGS
2356
2357 # See if we've got the necessary support.
2358 eval { require PadWalker; PadWalker->VERSION(0.08) }
2359 or &warn(
2360 $@ =~ /locate/
2361 ? "PadWalker module not found - please install\n"
2362 : $@
2363 )
2364 and next CMD;
2365
2366 # Load up dumpvar if we don't have it. If we can, that is.
e81465be 2367 do 'dumpvar.pl' || die $@ unless defined &main::dumpvar;
69893cff
RGS
2368 defined &main::dumpvar
2369 or print $OUT "dumpvar.pl not available.\n"
2370 and next CMD;
2371
2372 # Got all the modules we need. Find them and print them.
826b9a2e 2373 my @vars = split( ' ', $match_vars || '' );
69893cff
RGS
2374
2375 # Find the pad.
826b9a2e 2376 my $h = eval { PadWalker::peek_my( ( $match_level || 0 ) + 1 ) };
69893cff
RGS
2377
2378 # Oops. Can't find it.
2379 $@ and $@ =~ s/ at .*//, &warn($@), next CMD;
2380
2381 # Show the desired vars with dumplex().
2382 my $savout = select($OUT);
2383
2384 # Have dumplex dump the lexicals.
e22ea7cc 2385 dumpvar::dumplex( $_, $h->{$_},
69893cff 2386 defined $option{dumpDepth} ? $option{dumpDepth} : -1,
e22ea7cc
RF
2387 @vars )
2388 for sort keys %$h;
69893cff
RGS
2389 select($savout);
2390 next CMD;
826b9a2e 2391 }
69893cff
RGS
2392
2393=head3 COMMANDS NOT WORKING AFTER PROGRAM ENDS
2394
2395All of the commands below this point don't work after the program being
2396debugged has ended. All of them check to see if the program has ended; this
2397allows the commands to be relocated without worrying about a 'line of
2398demarcation' above which commands can be entered anytime, and below which
2399they can't.
2400
2401=head4 C<n> - single step, but don't trace down into subs
2402
2403Done by setting C<$single> to 2, which forces subs to execute straight through
be9a9b1d 2404when entered (see C<DB::sub>). We also save the C<n> command in C<$laststep>,
826b9a2e 2405so a null command knows what to re-execute.
69893cff
RGS
2406
2407=cut
2408
e22ea7cc 2409 # n - next
826b9a2e 2410 if ($cmd eq 'n') {
8481f647 2411 next CMD if _DB__is_finished();
e22ea7cc 2412
69893cff
RGS
2413 # Single step, but don't enter subs.
2414 $single = 2;
e22ea7cc 2415
69893cff 2416 # Save for empty command (repeat last).
e22ea7cc
RF
2417 $laststep = $cmd;
2418 last CMD;
826b9a2e 2419 }
69893cff
RGS
2420
2421=head4 C<s> - single-step, entering subs
2422
826b9a2e 2423Sets C<$single> to 1, which causes C<DB::sub> to continue tracing inside
69893cff
RGS
2424subs. Also saves C<s> as C<$lastcmd>.
2425
2426=cut
2427
2428 # s - single step.
826b9a2e 2429 if ($cmd eq 's') {
e22ea7cc 2430
69893cff
RGS
2431 # Get out and restart the command loop if program
2432 # has finished.
8481f647 2433 next CMD if _DB__is_finished();
e22ea7cc 2434
69893cff 2435 # Single step should enter subs.
e22ea7cc
RF
2436 $single = 1;
2437
69893cff 2438 # Save for empty command (repeat last).
e22ea7cc
RF
2439 $laststep = $cmd;
2440 last CMD;
826b9a2e 2441 }
69893cff
RGS
2442
2443=head4 C<c> - run continuously, setting an optional breakpoint
2444
2445Most of the code for this command is taken up with locating the optional
2446breakpoint, which is either a subroutine name or a line number. We set
2447the appropriate one-time-break in C<@dbline> and then turn off single-stepping
2448in this and all call levels above this one.
2449
2450=cut
2451
2452 # c - start continuous execution.
ef18ae63 2453 if (($i) = $cmd =~ m#\Ac\b\s*([\w:]*)\s*\z#) {
e22ea7cc 2454
69893cff
RGS
2455 # Hey, show's over. The debugged program finished
2456 # executing already.
8481f647 2457 next CMD if _DB__is_finished();
69893cff
RGS
2458
2459 # Capture the place to put a one-time break.
ef18ae63 2460 $subname = $i;
69893cff 2461
e22ea7cc
RF
2462 # Probably not needed, since we finish an interactive
2463 # sub-session anyway...
2464 # local $filename = $filename;
2465 # local *dbline = *dbline; # XXX Would this work?!
69893cff
RGS
2466 #
2467 # The above question wonders if localizing the alias
2468 # to the magic array works or not. Since it's commented
2469 # out, we'll just leave that to speculation for now.
2470
2471 # If the "subname" isn't all digits, we'll assume it
2472 # is a subroutine name, and try to find it.
e22ea7cc
RF
2473 if ( $subname =~ /\D/ ) { # subroutine name
2474 # Qualify it to the current package unless it's
2475 # already qualified.
69893cff
RGS
2476 $subname = $package . "::" . $subname
2477 unless $subname =~ /::/;
e22ea7cc 2478
69893cff
RGS
2479 # find_sub will return "file:line_number" corresponding
2480 # to where the subroutine is defined; we call find_sub,
e22ea7cc 2481 # break up the return value, and assign it in one
69893cff 2482 # operation.
e22ea7cc 2483 ( $file, $i ) = ( find_sub($subname) =~ /^(.*):(.*)$/ );
69893cff
RGS
2484
2485 # Force the line number to be numeric.
e22ea7cc 2486 $i += 0;
69893cff
RGS
2487
2488 # If we got a line number, we found the sub.
e22ea7cc
RF
2489 if ($i) {
2490
69893cff
RGS
2491 # Switch all the debugger's internals around so
2492 # we're actually working with that file.
e22ea7cc
RF
2493 $filename = $file;
2494 *dbline = $main::{ '_<' . $filename };
2495
69893cff 2496 # Mark that there's a breakpoint in this file.
e22ea7cc
RF
2497 $had_breakpoints{$filename} |= 1;
2498
69893cff
RGS
2499 # Scan forward to the first executable line
2500 # after the 'sub whatever' line.
e22ea7cc
RF
2501 $max = $#dbline;
2502 ++$i while $dbline[$i] == 0 && $i < $max;
2503 } ## end if ($i)
69893cff
RGS
2504
2505 # We didn't find a sub by that name.
e22ea7cc
RF
2506 else {
2507 print $OUT "Subroutine $subname not found.\n";
2508 next CMD;
2509 }
2510 } ## end if ($subname =~ /\D/)
69893cff
RGS
2511
2512 # At this point, either the subname was all digits (an
2513 # absolute line-break request) or we've scanned through
2514 # the code following the definition of the sub, looking
2515 # for an executable, which we may or may not have found.
2516 #
2517 # If $i (which we set $subname from) is non-zero, we
e22ea7cc
RF
2518 # got a request to break at some line somewhere. On
2519 # one hand, if there wasn't any real subroutine name
2520 # involved, this will be a request to break in the current
2521 # file at the specified line, so we have to check to make
69893cff
RGS
2522 # sure that the line specified really is breakable.
2523 #
2524 # On the other hand, if there was a subname supplied, the
3c4b39be 2525 # preceding block has moved us to the proper file and
69893cff
RGS
2526 # location within that file, and then scanned forward
2527 # looking for the next executable line. We have to make
2528 # sure that one was found.
2529 #
2530 # On the gripping hand, we can't do anything unless the
2531 # current value of $i points to a valid breakable line.
2532 # Check that.
e22ea7cc
RF
2533 if ($i) {
2534
69893cff 2535 # Breakable?
e22ea7cc
RF
2536 if ( $dbline[$i] == 0 ) {
2537 print $OUT "Line $i not breakable.\n";
2538 next CMD;
2539 }
2540
69893cff 2541 # Yes. Set up the one-time-break sigil.
e22ea7cc 2542 $dbline{$i} =~ s/($|\0)/;9$1/; # add one-time-only b.p.
5d5d9ea3 2543 _enable_breakpoint_temp_enabled_status($filename, $i);
e22ea7cc 2544 } ## end if ($i)
69893cff
RGS
2545
2546 # Turn off stack tracing from here up.
2c247e84
SF
2547 for my $i (0 .. $stack_depth) {
2548 $stack[ $i ] &= ~1;
e22ea7cc
RF
2549 }
2550 last CMD;
ef18ae63 2551 }
69893cff
RGS
2552
2553=head4 C<r> - return from a subroutine
2554
2555For C<r> to work properly, the debugger has to stop execution again
2556immediately after the return is executed. This is done by forcing
2557single-stepping to be on in the call level above the current one. If
2558we are printing return values when a C<r> is executed, set C<$doret>
2559appropriately, and force us out of the command loop.
2560
2561=cut
2562
2563 # r - return from the current subroutine.
ef18ae63 2564 if ($cmd eq 'r') {
e22ea7cc 2565
98dc9551 2566 # Can't do anything if the program's over.
8481f647 2567 next CMD if _DB__is_finished();
e22ea7cc 2568
69893cff 2569 # Turn on stack trace.
e22ea7cc
RF
2570 $stack[$stack_depth] |= 1;
2571
69893cff 2572 # Print return value unless the stack is empty.
e22ea7cc
RF
2573 $doret = $option{PrintRet} ? $stack_depth - 1 : -2;
2574 last CMD;
ef18ae63 2575 }
69893cff 2576
69893cff
RGS
2577=head4 C<T> - stack trace
2578
2579Just calls C<DB::print_trace>.
2580
2581=cut
2582
ef18ae63 2583 if ($cmd eq 'T') {
e22ea7cc
RF
2584 print_trace( $OUT, 1 ); # skip DB
2585 next CMD;
ef18ae63 2586 }
69893cff
RGS
2587
2588=head4 C<w> - List window around current line.
2589
2590Just calls C<DB::cmd_w>.
2591
2592=cut
2593
ef18ae63
SF
2594 if (my ($arg) = $cmd =~ /\Aw\b\s*(.*)/s) {
2595 &cmd_w( 'w', $arg );
2596 next CMD;
2597 }
69893cff
RGS
2598
2599=head4 C<W> - watch-expression processing.
2600
b570d64b 2601Just calls C<DB::cmd_W>.
69893cff
RGS
2602
2603=cut
2604
ef18ae63
SF
2605 if (my ($arg) = $cmd =~ /\AW\b\s*(.*)/s) {
2606 &cmd_W( 'W', $arg );
2607 next CMD;
2608 }
69893cff
RGS
2609
2610=head4 C</> - search forward for a string in the source
2611
ef18ae63 2612We take the argument and treat it as a pattern. If it turns out to be a
69893cff 2613bad one, we return the error we got from trying to C<eval> it and exit.
ef18ae63 2614If not, we create some code to do the search and C<eval> it so it can't
69893cff
RGS
2615mess us up.
2616
2617=cut
2618
ef18ae63
SF
2619 # The pattern as a string.
2620 use vars qw($inpat);
69893cff 2621
ef18ae63 2622 if (($inpat) = $cmd =~ m#\A/(.*)\z#) {
69893cff
RGS
2623
2624 # Remove the final slash.
e22ea7cc 2625 $inpat =~ s:([^\\])/$:$1:;
69893cff
RGS
2626
2627 # If the pattern isn't null ...
e22ea7cc 2628 if ( $inpat ne "" ) {
69893cff
RGS
2629
2630 # Turn of warn and die procesing for a bit.
e22ea7cc
RF
2631 local $SIG{__DIE__};
2632 local $SIG{__WARN__};
69893cff
RGS
2633
2634 # Create the pattern.
22fc883d 2635 eval 'no strict q/vars/; $inpat =~ m' . "\a$inpat\a";
e22ea7cc
RF
2636 if ( $@ ne "" ) {
2637
69893cff 2638 # Oops. Bad pattern. No biscuit.
e22ea7cc 2639 # Print the eval error and go back for more
69893cff 2640 # commands.
e22ea7cc
RF
2641 print $OUT "$@";
2642 next CMD;
2643 }
2644 $pat = $inpat;
2645 } ## end if ($inpat ne "")
69893cff
RGS
2646
2647 # Set up to stop on wrap-around.
e22ea7cc 2648 $end = $start;
69893cff
RGS
2649
2650 # Don't move off the current line.
e22ea7cc 2651 $incr = -1;
69893cff
RGS
2652
2653 # Done in eval so nothing breaks if the pattern
2654 # does something weird.
e22ea7cc 2655 eval '
22fc883d 2656 no strict q/vars/;
e22ea7cc 2657 for (;;) {
69893cff 2658 # Move ahead one line.
e22ea7cc 2659 ++$start;
69893cff
RGS
2660
2661 # Wrap if we pass the last line.
e22ea7cc 2662 $start = 1 if ($start > $max);
69893cff
RGS
2663
2664 # Stop if we have gotten back to this line again,
e22ea7cc 2665 last if ($start == $end);
69893cff
RGS
2666
2667 # A hit! (Note, though, that we are doing
2668 # case-insensitive matching. Maybe a qr//
2669 # expression would be better, so the user could
2670 # do case-sensitive matching if desired.
e22ea7cc
RF
2671 if ($dbline[$start] =~ m' . "\a$pat\a" . 'i) {
2672 if ($slave_editor) {
69893cff 2673 # Handle proper escaping in the slave.
e22ea7cc 2674 print $OUT "\032\032$filename:$start:0\n";
b570d64b 2675 }
e22ea7cc 2676 else {
69893cff 2677 # Just print the line normally.
e22ea7cc
RF
2678 print $OUT "$start:\t",$dbline[$start],"\n";
2679 }
69893cff 2680 # And quit since we found something.
e22ea7cc
RF
2681 last;
2682 }
2683 } ';
2684
69893cff 2685 # If we wrapped, there never was a match.
e22ea7cc
RF
2686 print $OUT "/$pat/: not found\n" if ( $start == $end );
2687 next CMD;
ef18ae63 2688 }
69893cff
RGS
2689
2690=head4 C<?> - search backward for a string in the source
2691
2692Same as for C</>, except the loop runs backwards.
2693
2694=cut
2695
2696 # ? - backward pattern search.
ef18ae63 2697 if (my ($inpat) = $cmd =~ m#\A\?(.*)\z#) {
69893cff
RGS
2698
2699 # Get the pattern, remove trailing question mark.
e22ea7cc 2700 $inpat =~ s:([^\\])\?$:$1:;
69893cff
RGS
2701
2702 # If we've got one ...
e22ea7cc 2703 if ( $inpat ne "" ) {
69893cff
RGS
2704
2705 # Turn off die & warn handlers.
e22ea7cc
RF
2706 local $SIG{__DIE__};
2707 local $SIG{__WARN__};
2708 eval '$inpat =~ m' . "\a$inpat\a";
2709
2710 if ( $@ ne "" ) {
2711
69893cff 2712 # Ouch. Not good. Print the error.
e22ea7cc
RF
2713 print $OUT $@;
2714 next CMD;
2715 }
2716 $pat = $inpat;
69893cff 2717 } ## end if ($inpat ne "")
e22ea7cc 2718
69893cff 2719 # Where we are now is where to stop after wraparound.
e22ea7cc 2720 $end = $start;
69893cff
RGS
2721
2722 # Don't move away from this line.
e22ea7cc 2723 $incr = -1;
69893cff
RGS
2724
2725 # Search inside the eval to prevent pattern badness
2726 # from killing us.
e22ea7cc 2727 eval '
22fc883d 2728 no strict q/vars/;
e22ea7cc 2729 for (;;) {
69893cff 2730 # Back up a line.
e22ea7cc 2731 --$start;
69893cff
RGS
2732
2733 # Wrap if we pass the first line.
e22ea7cc
RF
2734
2735 $start = $max if ($start <= 0);
69893cff
RGS
2736
2737 # Quit if we get back where we started,
e22ea7cc 2738 last if ($start == $end);
69893cff
RGS
2739
2740 # Match?
e22ea7cc
RF
2741 if ($dbline[$start] =~ m' . "\a$pat\a" . 'i) {
2742 if ($slave_editor) {
69893cff 2743 # Yep, follow slave editor requirements.
e22ea7cc 2744 print $OUT "\032\032$filename:$start:0\n";
b570d64b 2745 }
e22ea7cc 2746 else {
69893cff 2747 # Yep, just print normally.
e22ea7cc
RF
2748 print $OUT "$start:\t",$dbline[$start],"\n";
2749 }
69893cff
RGS
2750
2751 # Found, so done.
e22ea7cc
RF
2752 last;
2753 }
2754 } ';
2755
2756 # Say we failed if the loop never found anything,
2757 print $OUT "?$pat?: not found\n" if ( $start == $end );
2758 next CMD;
ef18ae63 2759 }
69893cff
RGS
2760
2761=head4 C<$rc> - Recall command
2762
2763Manages the commands in C<@hist> (which is created if C<Term::ReadLine> reports
2764that the terminal supports history). It find the the command required, puts it
2765into C<$cmd>, and redoes the loop to execute it.
2766
2767=cut
2768
e22ea7cc 2769 # $rc - recall command.
ef18ae63 2770 if (my ($minus, $arg) = $cmd =~ m#\A$rc+\s*(-)?(\d+)?\z#) {
69893cff
RGS
2771
2772 # No arguments, take one thing off history.
e22ea7cc 2773 pop(@hist) if length($cmd) > 1;
69893cff 2774
e22ea7cc 2775 # Relative (- found)?
69893cff 2776 # Y - index back from most recent (by 1 if bare minus)
e22ea7cc 2777 # N - go to that particular command slot or the last
69893cff 2778 # thing if nothing following.
ef18ae63 2779 $i = $minus ? ( $#hist - ( $arg || 1 ) ) : ( $arg || $#hist );
69893cff
RGS
2780
2781 # Pick out the command desired.
e22ea7cc 2782 $cmd = $hist[$i];
69893cff
RGS
2783
2784 # Print the command to be executed and restart the loop
2785 # with that command in the buffer.
e22ea7cc
RF
2786 print $OUT $cmd, "\n";
2787 redo CMD;
ef18ae63 2788 }
69893cff
RGS
2789
2790=head4 C<$sh$sh> - C<system()> command
2791
2792Calls the C<DB::system()> to handle the command. This keeps the C<STDIN> and
2793C<STDOUT> from getting messed up.
2794
2795=cut
2796
2797 # $sh$sh - run a shell command (if it's all ASCII).
2798 # Can't run shell commands with Unicode in the debugger, hmm.
ef18ae63 2799 if (my ($arg) = $cmd =~ m#\A$sh$sh\s*(.*)#ms) {
e22ea7cc 2800
69893cff 2801 # System it.
ef18ae63 2802 &system($arg);
e22ea7cc 2803 next CMD;
ef18ae63 2804 }
69893cff
RGS
2805
2806=head4 C<$rc I<pattern> $rc> - Search command history
2807
2808Another command to manipulate C<@hist>: this one searches it with a pattern.
be9a9b1d 2809If a command is found, it is placed in C<$cmd> and executed via C<redo>.
69893cff
RGS
2810
2811=cut
2812
e22ea7cc 2813 # $rc pattern $rc - find a command in the history.
ef18ae63 2814 if (my ($arg) = $cmd =~ /\A$rc([^$rc].*)\z/) {
e22ea7cc 2815
69893cff 2816 # Create the pattern to use.
ef18ae63 2817 $pat = "^$arg";
69893cff
RGS
2818
2819 # Toss off last entry if length is >1 (and it always is).
e22ea7cc 2820 pop(@hist) if length($cmd) > 1;
69893cff
RGS
2821
2822 # Look backward through the history.
72d7d80d 2823 for ( $i = $#hist ; $i ; --$i ) {
69893cff 2824 # Stop if we find it.
e22ea7cc
RF
2825 last if $hist[$i] =~ /$pat/;
2826 }
2827
2828 if ( !$i ) {
69893cff 2829
69893cff 2830 # Never found it.
e22ea7cc
RF
2831 print $OUT "No such command!\n\n";
2832 next CMD;
2833 }
69893cff
RGS
2834
2835 # Found it. Put it in the buffer, print it, and process it.
e22ea7cc
RF
2836 $cmd = $hist[$i];
2837 print $OUT $cmd, "\n";
2838 redo CMD;
ef18ae63 2839 }
69893cff 2840
ef18ae63 2841=head4 C<$sh> - Invoke a shell
69893cff
RGS
2842
2843Uses C<DB::system> to invoke a shell.
2844
2845=cut
2846
2847 # $sh - start a shell.
ef18ae63 2848 if ($cmd =~ /\A$sh\z/) {
e22ea7cc 2849
69893cff
RGS
2850 # Run the user's shell. If none defined, run Bourne.
2851 # We resume execution when the shell terminates.
e22ea7cc
RF
2852 &system( $ENV{SHELL} || "/bin/sh" );
2853 next CMD;
ef18ae63 2854 }
69893cff
RGS
2855
2856=head4 C<$sh I<command>> - Force execution of a command in a shell
2857
2858Like the above, but the command is passed to the shell. Again, we use
2859C<DB::system> to avoid problems with C<STDIN> and C<STDOUT>.
2860
2861=cut
2862
2863 # $sh command - start a shell and run a command in it.
ef18ae63 2864 if (my ($arg) = $cmd =~ m#\A$sh\s*(.*)#ms) {
e22ea7cc
RF
2865
2866 # XXX: using csh or tcsh destroys sigint retvals!
2867 #&system($1); # use this instead
69893cff
RGS
2868
2869 # use the user's shell, or Bourne if none defined.
ef18ae63 2870 &system( $ENV{SHELL} || "/bin/sh", "-c", $arg );
e22ea7cc 2871 next CMD;
ef18ae63 2872 }
69893cff
RGS
2873
2874=head4 C<H> - display commands in history
2875
2876Prints the contents of C<@hist> (if any).
2877
2878=cut
2879
ef18ae63 2880 if ($cmd =~ /\AH\b\s*\*/) {
7fddc82f
RF
2881 @hist = @truehist = ();
2882 print $OUT "History cleansed\n";
2883 next CMD;
ef18ae63 2884 }
e22ea7cc 2885
ef18ae63
SF
2886 if (my ($num)
2887 = $cmd =~ /\AH\b\s*(?:-(\d+))?/) {
e22ea7cc
RF
2888
2889 # Anything other than negative numbers is ignored by
69893cff 2890 # the (incorrect) pattern, so this test does nothing.
ef18ae63 2891 $end = $num ? ( $#hist - $num ) : 0;
69893cff
RGS
2892
2893 # Set to the minimum if less than zero.
e22ea7cc 2894 $hist = 0 if $hist < 0;
69893cff 2895
e22ea7cc 2896 # Start at the end of the array.
69893cff
RGS
2897 # Stay in while we're still above the ending value.
2898 # Tick back by one each time around the loop.
72d7d80d 2899 for ( $i = $#hist ; $i > $end ; $i-- ) {
69893cff
RGS
2900
2901 # Print the command unless it has no arguments.
e22ea7cc
RF
2902 print $OUT "$i: ", $hist[$i], "\n"
2903 unless $hist[$i] =~ /^.?$/;
2904 }
2905 next CMD;
ef18ae63 2906 }
69893cff
RGS
2907
2908=head4 C<man, doc, perldoc> - look up documentation
2909
2910Just calls C<runman()> to print the appropriate document.
2911
2912=cut
2913
e22ea7cc 2914 # man, perldoc, doc - show manual pages.
ef18ae63
SF
2915 if (my ($man_page)
2916 = $cmd =~ /\A(?:man|(?:perl)?doc)\b(?:\s+([^(]*))?\z/) {
2917 runman($man_page);
e22ea7cc 2918 next CMD;
ef18ae63 2919 }
69893cff
RGS
2920
2921=head4 C<p> - print
2922
2923Builds a C<print EXPR> expression in the C<$cmd>; this will get executed at
2924the bottom of the loop.
2925
2926=cut
2927
ef18ae63 2928 my $print_cmd = 'print {$DB::OUT} ';
69893cff 2929 # p - print (no args): print $_.
ef18ae63
SF
2930 if ($cmd eq 'p') {
2931 $cmd = $print_cmd . '$_';
2932 }
69893cff
RGS
2933
2934 # p - print the given expression.
ef18ae63 2935 $cmd =~ s/\Ap\b/$print_cmd /;
69893cff
RGS
2936
2937=head4 C<=> - define command alias
2938
2939Manipulates C<%alias> to add or list command aliases.
2940
2941=cut
2942
e22ea7cc 2943 # = - set up a command alias.
ef18ae63 2944 if ($cmd =~ s/\A=\s*//) {
e22ea7cc
RF
2945 my @keys;
2946 if ( length $cmd == 0 ) {
2947
69893cff 2948 # No args, get current aliases.
e22ea7cc
RF
2949 @keys = sort keys %alias;
2950 }
2951 elsif ( my ( $k, $v ) = ( $cmd =~ /^(\S+)\s+(\S.*)/ ) ) {
2952
69893cff
RGS
2953 # Creating a new alias. $k is alias name, $v is
2954 # alias value.
2955
e22ea7cc
RF
2956 # can't use $_ or kill //g state
2957 for my $x ( $k, $v ) {
2958
2959 # Escape "alarm" characters.
2960 $x =~ s/\a/\\a/g;
2961 }
69893cff
RGS
2962
2963 # Substitute key for value, using alarm chars
e22ea7cc 2964 # as separators (which is why we escaped them in
69893cff 2965 # the command).
e22ea7cc 2966 $alias{$k} = "s\a$k\a$v\a";
69893cff
RGS
2967
2968 # Turn off standard warn and die behavior.
e22ea7cc
RF
2969 local $SIG{__DIE__};
2970 local $SIG{__WARN__};
69893cff
RGS
2971
2972 # Is it valid Perl?
e22ea7cc
RF
2973 unless ( eval "sub { s\a$k\a$v\a }; 1" ) {
2974
69893cff 2975 # Nope. Bad alias. Say so and get out.
e22ea7cc
RF
2976 print $OUT "Can't alias $k to $v: $@\n";
2977 delete $alias{$k};
2978 next CMD;
2979 }
2980
69893cff 2981 # We'll only list the new one.
e22ea7cc 2982 @keys = ($k);
69893cff
RGS
2983 } ## end elsif (my ($k, $v) = ($cmd...
2984
2985 # The argument is the alias to list.
e22ea7cc
RF
2986 else {
2987 @keys = ($cmd);
2988 }
69893cff
RGS
2989
2990 # List aliases.
e22ea7cc
RF
2991 for my $k (@keys) {
2992
98dc9551 2993 # Messy metaquoting: Trim the substitution code off.
69893cff
RGS
2994 # We use control-G as the delimiter because it's not
2995 # likely to appear in the alias.
e22ea7cc
RF
2996 if ( ( my $v = $alias{$k} ) =~ s\as\a$k\a(.*)\a$\a1\a ) {
2997
69893cff 2998 # Print the alias.
e22ea7cc
RF
2999 print $OUT "$k\t= $1\n";
3000 }
3001 elsif ( defined $alias{$k} ) {
3002
69893cff 3003 # Couldn't trim it off; just print the alias code.
e22ea7cc
RF
3004 print $OUT "$k\t$alias{$k}\n";
3005 }
3006 else {
3007
69893cff 3008 # No such, dude.
e22ea7cc
RF
3009 print "No alias for $k\n";
3010 }
69893cff 3011 } ## end for my $k (@keys)
e22ea7cc 3012 next CMD;
ef18ae63 3013 }
69893cff
RGS
3014
3015=head4 C<source> - read commands from a file.
3016
3017Opens a lexical filehandle and stacks it on C<@cmdfhs>; C<DB::readline> will
3018pick it up.
3019
3020=cut
3021
e22ea7cc 3022 # source - read commands from a file (or pipe!) and execute.
ef18ae63
SF
3023 if (my ($sourced_fn) = $cmd =~ /\Asource\s+(.*\S)/) {
3024 if ( open my $fh, $sourced_fn ) {
e22ea7cc 3025
69893cff 3026 # Opened OK; stick it in the list of file handles.
e22ea7cc
RF
3027 push @cmdfhs, $fh;
3028 }
3029 else {
3030
3031 # Couldn't open it.
ef18ae63 3032 &warn("Can't execute '$sourced_fn': $!\n");
e22ea7cc
RF
3033 }
3034 next CMD;
ef18ae63 3035 }
69893cff 3036
ef18ae63
SF
3037 if (my ($which_cmd, $position)
3038 = $cmd =~ /^(enable|disable)\s+(\S+)\s*$/) {
e09195af
SF
3039
3040 my ($fn, $line_num);
3041 if ($position =~ m{\A\d+\z})
3042 {
3043 $fn = $filename;
3044 $line_num = $position;
3045 }
ef18ae63
SF
3046 elsif (my ($new_fn, $new_line_num)
3047 = $position =~ m{\A(.*):(\d+)\z}) {
3048 ($fn, $line_num) = ($new_fn, $new_line_num);
e09195af
SF
3049 }
3050 else
3051 {
3052 &warn("Wrong spec for enable/disable argument.\n");
3053 }
3054
3055 if (defined($fn)) {
3056 if (_has_breakpoint_data_ref($fn, $line_num)) {
3057 _set_breakpoint_enabled_status($fn, $line_num,
ef18ae63 3058 ($which_cmd eq 'enable' ? 1 : '')
e09195af
SF
3059 );
3060 }
3061 else {
3062 &warn("No breakpoint set at ${fn}:${line_num}\n");
3063 }
3064 }
3065
3066 next CMD;
ef18ae63 3067 }
e09195af 3068
69893cff
RGS
3069=head4 C<save> - send current history to a file
3070
3071Takes the complete history, (not the shrunken version you see with C<H>),
3072and saves it to the given filename, so it can be replayed using C<source>.
3073
3074Note that all C<^(save|source)>'s are commented out with a view to minimise recursion.
3075
3076=cut
3077
3078 # save source - write commands to a file for later use
ef18ae63
SF
3079 if (my ($new_fn) = $cmd =~ /\Asave\s*(.*)\z/) {
3080 my $filename = $new_fn || '.perl5dbrc'; # default?
3081 if ( open my $fh, '>', $filename ) {
e22ea7cc
RF
3082
3083 # chomp to remove extraneous newlines from source'd files
3084 chomp( my @truelist =
3085 map { m/^\s*(save|source)/ ? "#$_" : $_ }
3086 @truehist );
3087 print $fh join( "\n", @truelist );
69893cff 3088 print "commands saved in $file\n";
e22ea7cc
RF
3089 }
3090 else {
ef18ae63 3091 &warn("Can't save debugger commands in '$new_fn': $!\n");
69893cff
RGS
3092 }
3093 next CMD;
ef18ae63 3094 }
69893cff 3095
7fddc82f
RF
3096=head4 C<R> - restart
3097
ef18ae63 3098Restart the debugger session.
7fddc82f
RF
3099
3100=head4 C<rerun> - rerun the current session
3101
3102Return to any given position in the B<true>-history list
3103
3104=cut
3105
3106 # R - restart execution.
3107 # rerun - controlled restart execution.
ff41e38d
SF
3108 if (my ($cmd_cmd, $cmd_params) =
3109 $cmd =~ /\A((?:R)|(?:rerun\s*(.*)))\z/) {
3110 my @args = ($cmd_cmd eq 'R' ? restart() : rerun($cmd_params));
7fddc82f 3111
ca28b541
AP
3112 # Close all non-system fds for a clean restart. A more
3113 # correct method would be to close all fds that were not
3114 # open when the process started, but this seems to be
3115 # hard. See "debugger 'R'estart and open database
3116 # connections" on p5p.
3117
47d3bbda 3118 my $max_fd = 1024; # default if POSIX can't be loaded
ca28b541 3119 if (eval { require POSIX }) {
5332cc68 3120 eval { $max_fd = POSIX::sysconf(POSIX::_SC_OPEN_MAX()) };
ca28b541
AP
3121 }
3122
3123 if (defined $max_fd) {
3124 foreach ($^F+1 .. $max_fd-1) {
3125 next unless open FD_TO_CLOSE, "<&=$_";
3126 close(FD_TO_CLOSE);
3127 }
3128 }
3129
7fddc82f
RF
3130 # And run Perl again. We use exec() to keep the
3131 # PID stable (and that way $ini_pids is still valid).
3132 exec(@args) || print $OUT "exec failed: $!\n";
3133
3134 last CMD;
ff41e38d 3135 }
7fddc82f 3136
69893cff
RGS
3137=head4 C<|, ||> - pipe output through the pager.
3138
be9a9b1d 3139For C<|>, we save C<OUT> (the debugger's output filehandle) and C<STDOUT>
69893cff
RGS
3140(the program's standard output). For C<||>, we only save C<OUT>. We open a
3141pipe to the pager (restoring the output filehandles if this fails). If this
b570d64b 3142is the C<|> command, we also set up a C<SIGPIPE> handler which will simply
69893cff
RGS
3143set C<$signal>, sending us back into the debugger.
3144
3145We then trim off the pipe symbols and C<redo> the command loop at the
3146C<PIPE> label, causing us to evaluate the command in C<$cmd> without
3147reading another.
3148
3149=cut
3150
3151 # || - run command in the pager, with output to DB::OUT.
ff41e38d 3152 if ($cmd =~ m#\A\|\|?\s*[^|]#) {
e22ea7cc
RF
3153 if ( $pager =~ /^\|/ ) {
3154
69893cff 3155 # Default pager is into a pipe. Redirect I/O.
e22ea7cc
RF
3156 open( SAVEOUT, ">&STDOUT" )
3157 || &warn("Can't save STDOUT");
3158 open( STDOUT, ">&OUT" )
3159 || &warn("Can't redirect STDOUT");
69893cff 3160 } ## end if ($pager =~ /^\|/)
e22ea7cc
RF
3161 else {
3162
69893cff 3163 # Not into a pipe. STDOUT is safe.
e22ea7cc
RF
3164 open( SAVEOUT, ">&OUT" ) || &warn("Can't save DB::OUT");
3165 }
69893cff
RGS
3166
3167 # Fix up environment to record we have less if so.
e22ea7cc
RF
3168 fix_less();
3169
3170 unless ( $piped = open( OUT, $pager ) ) {
69893cff 3171
69893cff 3172 # Couldn't open pipe to pager.
1f874cb6 3173 &warn("Can't pipe output to '$pager'");
e22ea7cc
RF
3174 if ( $pager =~ /^\|/ ) {
3175
69893cff 3176 # Redirect I/O back again.
e22ea7cc
RF
3177 open( OUT, ">&STDOUT" ) # XXX: lost message
3178 || &warn("Can't restore DB::OUT");
3179 open( STDOUT, ">&SAVEOUT" )
3180 || &warn("Can't restore STDOUT");
3181 close(SAVEOUT);
69893cff 3182 } ## end if ($pager =~ /^\|/)
e22ea7cc
RF
3183 else {
3184
69893cff 3185 # Redirect I/O. STDOUT already safe.
e22ea7cc
RF
3186 open( OUT, ">&STDOUT" ) # XXX: lost message
3187 || &warn("Can't restore DB::OUT");
3188 }
3189 next CMD;
69893cff
RGS
3190 } ## end unless ($piped = open(OUT,...
3191
3192 # Set up broken-pipe handler if necessary.
e22ea7cc
RF
3193 $SIG{PIPE} = \&DB::catch
3194 if $pager =~ /^\|/
3195 && ( "" eq $SIG{PIPE} || "DEFAULT" eq $SIG{PIPE} );
69893cff 3196
70c9432b
SF
3197 OUT->autoflush(1);
3198 # Save current filehandle, and put it back.
e22ea7cc 3199 $selected = select(OUT);
69893cff 3200 # Don't put it back if pager was a pipe.
e22ea7cc 3201 select($selected), $selected = "" unless $cmd =~ /^\|\|/;
69893cff
RGS
3202
3203 # Trim off the pipe symbols and run the command now.
ff41e38d 3204 $cmd =~ s#\A\|+\s*##;
e22ea7cc 3205 redo PIPE;
ff41e38d 3206 }
69893cff
RGS
3207
3208=head3 END OF COMMAND PARSING
3209
ff41e38d
SF
3210Anything left in C<$cmd> at this point is a Perl expression that we want to
3211evaluate. We'll always evaluate in the user's context, and fully qualify
69893cff
RGS
3212any variables we might want to address in the C<DB> package.
3213
3214=cut
3215
3216 # t - turn trace on.
ff41e38d
SF
3217 if ($cmd =~ s#\At\s+(\d+)?#\$DB::trace |= 1;\n#) {
3218 my $trace_arg = $1;
3219 $trace_to_depth = $trace_arg ? $stack_depth||0 + $1 : 1E9;
3220 }
69893cff
RGS
3221
3222 # s - single-step. Remember the last command was 's'.
ff41e38d
SF
3223 if ($cmd =~ s/\As\s/\$DB::single = 1;\n/) {
3224 $laststep = 's';
3225 }
69893cff
RGS
3226
3227 # n - single-step, but not into subs. Remember last command
e22ea7cc 3228 # was 'n'.
ff41e38d
SF
3229 if ($cmd =~ s#\An\s#\$DB::single = 2;\n#) {
3230 $laststep = 'n';
3231 }
69893cff 3232
e22ea7cc 3233 } # PIPE:
69893cff 3234
e22ea7cc 3235 # Make sure the flag that says "the debugger's running" is
69893cff 3236 # still on, to make sure we get control again.
e22ea7cc 3237 $evalarg = "\$^D = \$^D | \$DB::db_stop;\n$cmd";
69893cff
RGS
3238
3239 # Run *our* eval that executes in the caller's context.
7c54f46a 3240 DB::eval();
69893cff
RGS
3241
3242 # Turn off the one-time-dump stuff now.
e22ea7cc
RF
3243 if ($onetimeDump) {
3244 $onetimeDump = undef;
69893cff 3245 $onetimedumpDepth = undef;
e22ea7cc
RF
3246 }
3247 elsif ( $term_pid == $$ ) {
8380a245 3248 eval { # May run under miniperl, when not available...
c7e68384
IZ
3249 STDOUT->flush();
3250 STDERR->flush();
8380a245 3251 };
e22ea7cc 3252
69893cff 3253 # XXX If this is the master pid, print a newline.
8380a245 3254 print {$OUT} "\n";
e22ea7cc
RF
3255 }
3256 } ## end while (($term || &setterm...
69893cff
RGS
3257
3258=head3 POST-COMMAND PROCESSING
3259
3260After each command, we check to see if the command output was piped anywhere.
3261If so, we go through the necessary code to unhook the pipe and go back to
3262our standard filehandles for input and output.
3263
3264=cut
3265
e22ea7cc 3266 continue { # CMD:
69893cff
RGS
3267
3268 # At the end of every command:
e22ea7cc
RF
3269 if ($piped) {
3270
69893cff 3271 # Unhook the pipe mechanism now.
e22ea7cc
RF
3272 if ( $pager =~ /^\|/ ) {
3273
69893cff 3274 # No error from the child.
e22ea7cc 3275 $? = 0;
69893cff 3276
e22ea7cc
RF
3277 # we cannot warn here: the handle is missing --tchrist
3278 close(OUT) || print SAVEOUT "\nCan't close DB::OUT\n";
69893cff 3279
e22ea7cc 3280 # most of the $? crud was coping with broken cshisms
69893cff 3281 # $? is explicitly set to 0, so this never runs.
e22ea7cc 3282 if ($?) {
1f874cb6 3283 print SAVEOUT "Pager '$pager' failed: ";
e22ea7cc
RF
3284 if ( $? == -1 ) {
3285 print SAVEOUT "shell returned -1\n";
3286 }
3287 elsif ( $? >> 8 ) {
3288 print SAVEOUT ( $? & 127 )
3289 ? " (SIG#" . ( $? & 127 ) . ")"
3290 : "", ( $? & 128 ) ? " -- core dumped" : "", "\n";
3291 }
3292 else {
3293 print SAVEOUT "status ", ( $? >> 8 ), "\n";
3294 }
69893cff
RGS
3295 } ## end if ($?)
3296
e22ea7cc 3297 # Reopen filehandle for our output (if we can) and
69893cff 3298 # restore STDOUT (if we can).
e22ea7cc
RF
3299 open( OUT, ">&STDOUT" ) || &warn("Can't restore DB::OUT");
3300 open( STDOUT, ">&SAVEOUT" )
3301 || &warn("Can't restore STDOUT");
69893cff
RGS
3302
3303 # Turn off pipe exception handler if necessary.
e22ea7cc 3304 $SIG{PIPE} = "DEFAULT" if $SIG{PIPE} eq \&DB::catch;
69893cff 3305
e22ea7cc
RF
3306 # Will stop ignoring SIGPIPE if done like nohup(1)
3307 # does SIGINT but Perl doesn't give us a choice.
69893cff 3308 } ## end if ($pager =~ /^\|/)
e22ea7cc
RF
3309 else {
3310
69893cff 3311 # Non-piped "pager". Just restore STDOUT.
e22ea7cc
RF
3312 open( OUT, ">&SAVEOUT" ) || &warn("Can't restore DB::OUT");
3313 }
69893cff
RGS
3314
3315 # Close filehandle pager was using, restore the normal one
3316 # if necessary,
3317 close(SAVEOUT);
e22ea7cc 3318 select($selected), $selected = "" unless $selected eq "";
69893cff
RGS
3319
3320 # No pipes now.
e22ea7cc 3321 $piped = "";
69893cff 3322 } ## end if ($piped)
e22ea7cc 3323 } # CMD:
69893cff
RGS
3324
3325=head3 COMMAND LOOP TERMINATION
3326
3327When commands have finished executing, we come here. If the user closed the
3328input filehandle, we turn on C<$fall_off_end> to emulate a C<q> command. We
3329evaluate any post-prompt items. We restore C<$@>, C<$!>, C<$^E>, C<$,>, C<$/>,
3330C<$\>, and C<$^W>, and return a null list as expected by the Perl interpreter.
3331The interpreter will then execute the next line and then return control to us
3332again.
3333
3334=cut
3335
3336 # No more commands? Quit.
1f874cb6 3337 $fall_off_end = 1 unless defined $cmd; # Emulate 'q' on EOF
69893cff
RGS
3338
3339 # Evaluate post-prompt commands.
e22ea7cc 3340 foreach $evalarg (@$post) {
7c54f46a 3341 DB::eval();
e22ea7cc
RF
3342 }
3343 } # if ($single || $signal)
69893cff
RGS
3344
3345 # Put the user's globals back where you found them.
e22ea7cc 3346 ( $@, $!, $^E, $,, $/, $\, $^W ) = @saved;
69893cff
RGS
3347 ();
3348} ## end sub DB
3349
22fc883d
SF
3350package DB::Obj;
3351
3352sub new {
3353 my $class = shift;
3354
3355 my $self = bless {}, $class;
3356
3357 $self->_init(@_);
3358
3359 return $self;
3360}
3361
3362sub _init {
3363 my ($self, $args) = @_;
3364
3365 %{$self} = (%$self, %$args);
3366
3367 return;
3368}
3369
3370{
3371 no strict 'refs';
3372 foreach my $slot_name (qw(after explicit_stop infix position prefix)) {
3373 my $slot = $slot_name;
3374 *{$slot} = sub {
3375 my $self = shift;
3376
3377 if (@_) {
3378 ${ $self->{$slot} } = shift;
3379 }
3380
3381 return ${ $self->{$slot} };
3382 };
8def6eff
SF
3383
3384 *{"append_to_$slot"} = sub {
3385 my $self = shift;
3386 my $s = shift;
3387
3388 return $self->$slot($self->$slot . $s);
3389 };
22fc883d
SF
3390 }
3391}
3392
3393sub _DB_on_init__initialize_globals
3394{
3395 my $self = shift;
3396
3397 # Check for whether we should be running continuously or not.
3398 # _After_ the perl program is compiled, $single is set to 1:
ebd0282e 3399 if ( $single and not $second_time++ ) {
22fc883d
SF
3400
3401 # Options say run non-stop. Run until we get an interrupt.
ebd0282e 3402 if ($runnonstop) { # Disable until signal
22fc883d
SF
3403 # If there's any call stack in place, turn off single
3404 # stepping into subs throughout the stack.
8ad70697
SF
3405 for my $i (0 .. $stack_depth) {
3406 $stack[ $i ] &= ~1;
22fc883d
SF
3407 }
3408
3409 # And we are now no longer in single-step mode.
ebd0282e 3410 $single = 0;
22fc883d
SF
3411
3412 # If we simply returned at this point, we wouldn't get
3413 # the trace info. Fall on through.
3414 # return;
3415 } ## end if ($runnonstop)
3416
8ad70697 3417 elsif ($ImmediateStop) {
22fc883d
SF
3418
3419 # We are supposed to stop here; XXX probably a break.
8ad70697 3420 $ImmediateStop = 0; # We've processed it; turn it off
ebd0282e 3421 $signal = 1; # Simulate an interrupt to force
22fc883d
SF
3422 # us into the command loop
3423 }
3424 } ## end if ($single and not $second_time...
3425
3426 # If we're in single-step mode, or an interrupt (real or fake)
3427 # has occurred, turn off non-stop mode.
ebd0282e 3428 $runnonstop = 0 if $single or $signal;
22fc883d
SF
3429
3430 return;
3431}
3432
3433sub _DB__handle_watch_expressions
3434{
3435 my $self = shift;
3436
931ac036 3437 if ( $trace & 2 ) {
8ad70697
SF
3438 for my $n (0 .. $#to_watch) {
3439 $evalarg = $to_watch[$n];
3440 local $onetimeDump; # Tell DB::eval() to not output results
22fc883d
SF
3441
3442 # Fix context DB::eval() wants to return an array, but
3443 # we need a scalar here.
7c54f46a 3444 my ($val) = join( "', '", DB::eval() );
22fc883d
SF
3445 $val = ( ( defined $val ) ? "'$val'" : 'undef' );
3446
3447 # Did it change?
8ad70697 3448 if ( $val ne $old_watch[$n] ) {
22fc883d
SF
3449
3450 # Yep! Show the difference, and fake an interrupt.
ebd0282e 3451 $signal = 1;
8ad70697
SF
3452 print {$OUT} <<EOP;
3453Watchpoint $n:\t$to_watch[$n] changed:
3454 old value:\t$old_watch[$n]
22fc883d
SF
3455 new value:\t$val
3456EOP
8ad70697 3457 $old_watch[$n] = $val;
22fc883d
SF
3458 } ## end if ($val ne $old_watch...
3459 } ## end for my $n (0 ..
3460 } ## end if ($trace & 2)
3461
3462 return;
3463}
3464
ad46ac70
SF
3465sub _my_print_lineinfo
3466{
3467 my ($self, $i, $incr_pos) = @_;
3468
18b5b545 3469 if ($frame) {
ad46ac70 3470 # Print it indented if tracing is on.
8ad70697 3471 DB::print_lineinfo( ' ' x $stack_depth,
ad46ac70
SF
3472 "$i:\t$DB::dbline[$i]" . $self->after );
3473 }
3474 else {
3475 DB::depth_print_lineinfo($self->explicit_stop, $incr_pos);
3476 }
3477}
3478
44a07e3e 3479sub _curr_line {
18b5b545 3480 return $DB::dbline[$line];
44a07e3e
SF
3481}
3482
22fc883d
SF
3483sub _DB__grab_control
3484{
3485 my $self = shift;
3486
3487 # Yes, grab control.
7793e5c2 3488 if ($slave_editor) {
22fc883d
SF
3489
3490 # Tell the editor to update its position.
18b5b545 3491 $self->position("\032\032${DB::filename}:$line:0\n");
22fc883d
SF
3492 DB::print_lineinfo($self->position());
3493 }
3494
3495=pod
3496
3497Special check: if we're in package C<DB::fake>, we've gone through the
3498C<END> block at least once. We set up everything so that we can continue
3499to enter commands and have a valid context to be in.
3500
3501=cut
3502
3503 elsif ( $DB::package eq 'DB::fake' ) {
3504
3505 # Fallen off the end already.
3506 if (!$DB::term) {
3507 DB::setterm();
3508 }
3509
3510 DB::print_help(<<EOP);
3511Debugged program terminated. Use B<q> to quit or B<R> to restart,
3512use B<o> I<inhibit_exit> to avoid stopping after program termination,
3513B<h q>, B<h R> or B<h o> to get additional info.
3514EOP
3515
3516 # Set the DB::eval context appropriately.
3517 $DB::package = 'main';
3518 $DB::usercontext = DB::_calc_usercontext($DB::package);
3519 } ## end elsif ($package eq 'DB::fake')
3520
3521=pod
3522
3523If the program hasn't finished executing, we scan forward to the
3524next executable line, print that out, build the prompt from the file and line
3525number information, and print that.
3526
3527=cut
3528
3529 else {
3530
3531
3532 # Still somewhere in the midst of execution. Set up the
3533 # debugger prompt.
3534 $DB::sub =~ s/\'/::/; # Swap Perl 4 package separators (') to
3535 # Perl 5 ones (sorry, we don't print Klingon
3536 #module names)
3537
3538 $self->prefix($DB::sub =~ /::/ ? "" : ($DB::package . '::'));
8def6eff 3539 $self->append_to_prefix( "$DB::sub(${DB::filename}:" );
44a07e3e 3540 $self->after( $self->_curr_line =~ /\n$/ ? '' : "\n" );
22fc883d
SF
3541
3542 # Break up the prompt if it's really long.
3543 if ( length($self->prefix()) > 30 ) {
18b5b545 3544 $self->position($self->prefix . "$line):\n$line:\t" . $self->_curr_line . $self->after);
22fc883d
SF
3545 $self->prefix("");
3546 $self->infix(":\t");
3547 }
3548 else {
3549 $self->infix("):\t");
3550 $self->position(
18b5b545 3551 $self->prefix . $line. $self->infix
44a07e3e 3552 . $self->_curr_line . $self->after
22fc883d
SF
3553 );
3554 }
3555
3556 # Print current line info, indenting if necessary.
18b5b545 3557 $self->_my_print_lineinfo($line, $self->position);
22fc883d 3558
44a07e3e
SF
3559 my $i;
3560 my $line_i = sub { return $DB::dbline[$i]; };
3561
22fc883d
SF
3562 # Scan forward, stopping at either the end or the next
3563 # unbreakable line.
18b5b545 3564 for ( $i = $line + 1 ; $i <= $DB::max && $line_i->() == 0 ; ++$i )
22fc883d
SF
3565 { #{ vi
3566
3567 # Drop out on null statements, block closers, and comments.
44a07e3e 3568 last if $line_i->() =~ /^\s*[\;\}\#\n]/;
22fc883d
SF
3569
3570 # Drop out if the user interrupted us.
ebd0282e 3571 last if $signal;
22fc883d
SF
3572
3573 # Append a newline if the line doesn't have one. Can happen
3574 # in eval'ed text, for instance.
44a07e3e 3575 $self->after( $line_i->() =~ /\n$/ ? '' : "\n" );
22fc883d
SF
3576
3577 # Next executable line.
44a07e3e 3578 my $incr_pos = $self->prefix . $i . $self->infix . $line_i->()
22fc883d 3579 . $self->after;
8def6eff 3580 $self->append_to_position($incr_pos);
ad46ac70 3581 $self->_my_print_lineinfo($i, $incr_pos);
22fc883d
SF
3582 } ## end for ($i = $line + 1 ; $i...
3583 } ## end else [ if ($slave_editor)
3584
3585 return;
3586}
3587
174f9c5e
SF
3588sub _handle_t_command {
3589 if (my ($levels) = $DB::cmd =~ /\At(?:\s+(\d+))?\z/) {
931ac036 3590 $trace ^= 1;
174f9c5e