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[perl5db-refactor] Refactoring.
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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 *
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be9a9b1d 137First, doing an arithmetical or bitwise operation on a scalar is
69893cff 138just about the fastest thing you can do in Perl: C<use constant> actually
be9a9b1d 139creates a subroutine call, and array and hash lookups are much slower. Is
b570d64b 140this over-optimization at the expense of readability? Possibly, but the
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141debugger accesses these variables a I<lot>. Any rewrite of the code will
142probably have to benchmark alternate implementations and see which is the
b570d64b 143best balance of readability and speed, and then document how it actually
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144works.
145
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146=item *
147
b570d64b 148Second, it's very easy to serialize a scalar number. This is done in
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149the restart code; the debugger state variables are saved in C<%ENV> and then
150restored when the debugger is restarted. Having them be just numbers makes
b570d64b 151this trivial.
69893cff 152
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153=item *
154
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155Third, some of these variables are being shared with the Perl core
156smack in the middle of the interpreter's execution loop. It's much faster for
157a C program (like the interpreter) to check a bit in a scalar than to access
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158several different variables (or a Perl array).
159
160=back
161
162=head2 What are those C<XXX> comments for?
163
164Any comment containing C<XXX> means that the comment is either somewhat
b570d64b 165speculative - it's not exactly clear what a given variable or chunk of
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166code is doing, or that it is incomplete - the basics may be clear, but the
167subtleties are not completely documented.
168
169Send in a patch if you can clear up, fill out, or clarify an C<XXX>.
170
b570d64b 171=head1 DATA STRUCTURES MAINTAINED BY CORE
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172
173There are a number of special data structures provided to the debugger by
174the Perl interpreter.
175
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176The array C<@{$main::{'_<'.$filename}}> (aliased locally to C<@dbline>
177via glob assignment) contains the text from C<$filename>, with each
178element corresponding to a single line of C<$filename>. Additionally,
179breakable lines will be dualvars with the numeric component being the
180memory address of a COP node. Non-breakable lines are dualvar to 0.
69893cff 181
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182The hash C<%{'_<'.$filename}> (aliased locally to C<%dbline> via glob
183assignment) contains breakpoints and actions. The keys are line numbers;
184you can set individual values, but not the whole hash. The Perl interpreter
69893cff 185uses this hash to determine where breakpoints have been set. Any true value is
be9a9b1d 186considered to be a breakpoint; C<perl5db.pl> uses C<$break_condition\0$action>.
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187Values are magical in numeric context: 1 if the line is breakable, 0 if not.
188
ef18ae63 189The scalar C<${"_<$filename"}> simply contains the string C<<< _<$filename> >>>.
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190This is also the case for evaluated strings that contain subroutines, or
191which are currently being executed. The $filename for C<eval>ed strings looks
d24ca0c5 192like C<(eval 34).
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193
194=head1 DEBUGGER STARTUP
195
196When C<perl5db.pl> starts, it reads an rcfile (C<perl5db.ini> for
197non-interactive sessions, C<.perldb> for interactive ones) that can set a number
198of options. In addition, this file may define a subroutine C<&afterinit>
b570d64b 199that will be executed (in the debugger's context) after the debugger has
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200initialized itself.
201
b570d64b 202Next, it checks the C<PERLDB_OPTS> environment variable and treats its
be9a9b1d 203contents as the argument of a C<o> command in the debugger.
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204
205=head2 STARTUP-ONLY OPTIONS
206
207The following options can only be specified at startup.
208To set them in your rcfile, add a call to
209C<&parse_options("optionName=new_value")>.
210
211=over 4
212
b570d64b 213=item * TTY
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214
215the TTY to use for debugging i/o.
216
b570d64b 217=item * noTTY
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218
219if set, goes in NonStop mode. On interrupt, if TTY is not set,
b0e77abc 220uses the value of noTTY or F<$HOME/.perldbtty$$> to find TTY using
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221Term::Rendezvous. Current variant is to have the name of TTY in this
222file.
223
b570d64b 224=item * ReadLine
69893cff 225
5561b870 226if false, a dummy ReadLine is used, so you can debug
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227ReadLine applications.
228
b570d64b 229=item * NonStop
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230
231if true, no i/o is performed until interrupt.
232
b570d64b 233=item * LineInfo
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234
235file or pipe to print line number info to. If it is a
236pipe, a short "emacs like" message is used.
237
b570d64b 238=item * RemotePort
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239
240host:port to connect to on remote host for remote debugging.
241
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242=item * HistFile
243
244file to store session history to. There is no default and so no
245history file is written unless this variable is explicitly set.
246
247=item * HistSize
248
249number of commands to store to the file specified in C<HistFile>.
250Default is 100.
251
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252=back
253
254=head3 SAMPLE RCFILE
255
256 &parse_options("NonStop=1 LineInfo=db.out");
257 sub afterinit { $trace = 1; }
258
259The script will run without human intervention, putting trace
260information into C<db.out>. (If you interrupt it, you had better
be9a9b1d 261reset C<LineInfo> to something I<interactive>!)
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262
263=head1 INTERNALS DESCRIPTION
264
265=head2 DEBUGGER INTERFACE VARIABLES
266
267Perl supplies the values for C<%sub>. It effectively inserts
be9a9b1d 268a C<&DB::DB();> in front of each place that can have a
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269breakpoint. At each subroutine call, it calls C<&DB::sub> with
270C<$DB::sub> set to the called subroutine. It also inserts a C<BEGIN
271{require 'perl5db.pl'}> before the first line.
272
273After each C<require>d file is compiled, but before it is executed, a
274call to C<&DB::postponed($main::{'_<'.$filename})> is done. C<$filename>
275is the expanded name of the C<require>d file (as found via C<%INC>).
276
277=head3 IMPORTANT INTERNAL VARIABLES
278
279=head4 C<$CreateTTY>
280
281Used to control when the debugger will attempt to acquire another TTY to be
b570d64b 282used for input.
69893cff 283
b570d64b 284=over
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285
286=item * 1 - on C<fork()>
287
288=item * 2 - debugger is started inside debugger
289
290=item * 4 - on startup
291
292=back
293
294=head4 C<$doret>
295
296The value -2 indicates that no return value should be printed.
297Any other positive value causes C<DB::sub> to print return values.
298
299=head4 C<$evalarg>
300
301The item to be eval'ed by C<DB::eval>. Used to prevent messing with the current
302contents of C<@_> when C<DB::eval> is called.
303
304=head4 C<$frame>
305
306Determines what messages (if any) will get printed when a subroutine (or eval)
b570d64b 307is entered or exited.
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308
309=over 4
310
311=item * 0 - No enter/exit messages
312
be9a9b1d 313=item * 1 - Print I<entering> messages on subroutine entry
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314
315=item * 2 - Adds exit messages on subroutine exit. If no other flag is on, acts like 1+2.
316
be9a9b1d 317=item * 4 - Extended messages: C<< <in|out> I<context>=I<fully-qualified sub name> from I<file>:I<line> >>. If no other flag is on, acts like 1+4.
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318
319=item * 8 - Adds parameter information to messages, and overloaded stringify and tied FETCH is enabled on the printed arguments. Ignored if C<4> is not on.
320
321=item * 16 - Adds C<I<context> return from I<subname>: I<value>> messages on subroutine/eval exit. Ignored if C<4> is is not on.
322
323=back
324
be9a9b1d 325To get everything, use C<$frame=30> (or C<o f=30> as a debugger command).
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326The debugger internally juggles the value of C<$frame> during execution to
327protect external modules that the debugger uses from getting traced.
328
329=head4 C<$level>
330
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331Tracks current debugger nesting level. Used to figure out how many
332C<E<lt>E<gt>> pairs to surround the line number with when the debugger
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333outputs a prompt. Also used to help determine if the program has finished
334during command parsing.
335
336=head4 C<$onetimeDump>
337
338Controls what (if anything) C<DB::eval()> will print after evaluating an
339expression.
340
341=over 4
342
343=item * C<undef> - don't print anything
344
345=item * C<dump> - use C<dumpvar.pl> to display the value returned
346
347=item * C<methods> - print the methods callable on the first item returned
348
349=back
350
351=head4 C<$onetimeDumpDepth>
352
be9a9b1d 353Controls how far down C<dumpvar.pl> will go before printing C<...> while
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354dumping a structure. Numeric. If C<undef>, print all levels.
355
356=head4 C<$signal>
357
358Used to track whether or not an C<INT> signal has been detected. C<DB::DB()>,
359which is called before every statement, checks this and puts the user into
360command mode if it finds C<$signal> set to a true value.
361
362=head4 C<$single>
363
364Controls behavior during single-stepping. Stacked in C<@stack> on entry to
365each subroutine; popped again at the end of each subroutine.
366
b570d64b 367=over 4
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368
369=item * 0 - run continuously.
370
be9a9b1d 371=item * 1 - single-step, go into subs. The C<s> command.
69893cff 372
be9a9b1d 373=item * 2 - single-step, don't go into subs. The C<n> command.
69893cff 374
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375=item * 4 - print current sub depth (turned on to force this when C<too much
376recursion> occurs.
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377
378=back
379
380=head4 C<$trace>
381
b570d64b 382Controls the output of trace information.
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383
384=over 4
385
386=item * 1 - The C<t> command was entered to turn on tracing (every line executed is printed)
387
388=item * 2 - watch expressions are active
389
390=item * 4 - user defined a C<watchfunction()> in C<afterinit()>
391
392=back
393
394=head4 C<$slave_editor>
395
3961 if C<LINEINFO> was directed to a pipe; 0 otherwise.
397
398=head4 C<@cmdfhs>
399
400Stack of filehandles that C<DB::readline()> will read commands from.
401Manipulated by the debugger's C<source> command and C<DB::readline()> itself.
402
403=head4 C<@dbline>
404
b570d64b 405Local alias to the magical line array, C<@{$main::{'_<'.$filename}}> ,
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406supplied by the Perl interpreter to the debugger. Contains the source.
407
408=head4 C<@old_watch>
409
410Previous values of watch expressions. First set when the expression is
411entered; reset whenever the watch expression changes.
412
413=head4 C<@saved>
414
415Saves important globals (C<$@>, C<$!>, C<$^E>, C<$,>, C<$/>, C<$\>, C<$^W>)
416so that the debugger can substitute safe values while it's running, and
417restore them when it returns control.
418
419=head4 C<@stack>
420
421Saves the current value of C<$single> on entry to a subroutine.
422Manipulated by the C<c> command to turn off tracing in all subs above the
423current one.
424
425=head4 C<@to_watch>
426
427The 'watch' expressions: to be evaluated before each line is executed.
428
429=head4 C<@typeahead>
430
431The typeahead buffer, used by C<DB::readline>.
432
433=head4 C<%alias>
434
435Command aliases. Stored as character strings to be substituted for a command
436entered.
437
438=head4 C<%break_on_load>
439
440Keys are file names, values are 1 (break when this file is loaded) or undef
441(don't break when it is loaded).
442
443=head4 C<%dbline>
444
be9a9b1d 445Keys are line numbers, values are C<condition\0action>. If used in numeric
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446context, values are 0 if not breakable, 1 if breakable, no matter what is
447in the actual hash entry.
448
449=head4 C<%had_breakpoints>
450
451Keys are file names; values are bitfields:
452
b570d64b 453=over 4
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454
455=item * 1 - file has a breakpoint in it.
456
457=item * 2 - file has an action in it.
458
459=back
460
461A zero or undefined value means this file has neither.
462
463=head4 C<%option>
464
465Stores the debugger options. These are character string values.
466
467=head4 C<%postponed>
468
469Saves breakpoints for code that hasn't been compiled yet.
470Keys are subroutine names, values are:
471
472=over 4
473
be9a9b1d 474=item * C<compile> - break when this sub is compiled
69893cff 475
be9a9b1d 476=item * C<< break +0 if <condition> >> - break (conditionally) at the start of this routine. The condition will be '1' if no condition was specified.
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477
478=back
479
480=head4 C<%postponed_file>
481
482This hash keeps track of breakpoints that need to be set for files that have
483not yet been compiled. Keys are filenames; values are references to hashes.
484Each of these hashes is keyed by line number, and its values are breakpoint
be9a9b1d 485definitions (C<condition\0action>).
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486
487=head1 DEBUGGER INITIALIZATION
488
489The debugger's initialization actually jumps all over the place inside this
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490package. This is because there are several BEGIN blocks (which of course
491execute immediately) spread through the code. Why is that?
69893cff 492
b570d64b 493The debugger needs to be able to change some things and set some things up
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494before the debugger code is compiled; most notably, the C<$deep> variable that
495C<DB::sub> uses to tell when a program has recursed deeply. In addition, the
496debugger has to turn off warnings while the debugger code is compiled, but then
497restore them to their original setting before the program being debugged begins
498executing.
499
500The first C<BEGIN> block simply turns off warnings by saving the current
501setting of C<$^W> and then setting it to zero. The second one initializes
502the debugger variables that are needed before the debugger begins executing.
b570d64b 503The third one puts C<$^X> back to its former value.
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504
505We'll detail the second C<BEGIN> block later; just remember that if you need
506to initialize something before the debugger starts really executing, that's
507where it has to go.
508
509=cut
510
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511package DB;
512
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513use strict;
514
c7e68384 515BEGIN {eval 'use IO::Handle'}; # Needed for flush only? breaks under miniperl
9eba6a4e 516
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517BEGIN {
518 require feature;
519 $^V =~ /^v(\d+\.\d+)/;
520 feature->import(":$1");
521}
522
54d04a52 523# Debugger for Perl 5.00x; perl5db.pl patch level:
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524use vars qw($VERSION $header);
525
b5afd346 526$VERSION = '1.39_04';
69893cff 527
e22ea7cc 528$header = "perl5db.pl version $VERSION";
d338d6fe 529
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530=head1 DEBUGGER ROUTINES
531
532=head2 C<DB::eval()>
533
534This function replaces straight C<eval()> inside the debugger; it simplifies
535the process of evaluating code in the user's context.
536
b570d64b 537The code to be evaluated is passed via the package global variable
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538C<$DB::evalarg>; this is done to avoid fiddling with the contents of C<@_>.
539
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540Before we do the C<eval()>, we preserve the current settings of C<$trace>,
541C<$single>, C<$^D> and C<$usercontext>. The latter contains the
542preserved values of C<$@>, C<$!>, C<$^E>, C<$,>, C<$/>, C<$\>, C<$^W> and the
543user's current package, grabbed when C<DB::DB> got control. This causes the
544proper context to be used when the eval is actually done. Afterward, we
545restore C<$trace>, C<$single>, and C<$^D>.
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546
547Next we need to handle C<$@> without getting confused. We save C<$@> in a
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548local lexical, localize C<$saved[0]> (which is where C<save()> will put
549C<$@>), and then call C<save()> to capture C<$@>, C<$!>, C<$^E>, C<$,>,
69893cff 550C<$/>, C<$\>, and C<$^W>) and set C<$,>, C<$/>, C<$\>, and C<$^W> to values
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551considered sane by the debugger. If there was an C<eval()> error, we print
552it on the debugger's output. If C<$onetimedump> is defined, we call
553C<dumpit> if it's set to 'dump', or C<methods> if it's set to
554'methods'. Setting it to something else causes the debugger to do the eval
555but not print the result - handy if you want to do something else with it
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556(the "watch expressions" code does this to get the value of the watch
557expression but not show it unless it matters).
558
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559In any case, we then return the list of output from C<eval> to the caller,
560and unwinding restores the former version of C<$@> in C<@saved> as well
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561(the localization of C<$saved[0]> goes away at the end of this scope).
562
563=head3 Parameters and variables influencing execution of DB::eval()
564
565C<DB::eval> isn't parameterized in the standard way; this is to keep the
566debugger's calls to C<DB::eval()> from mucking with C<@_>, among other things.
b570d64b 567The variables listed below influence C<DB::eval()>'s execution directly.
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568
569=over 4
570
571=item C<$evalarg> - the thing to actually be eval'ed
572
be9a9b1d 573=item C<$trace> - Current state of execution tracing
69893cff 574
be9a9b1d 575=item C<$single> - Current state of single-stepping
69893cff 576
b570d64b 577=item C<$onetimeDump> - what is to be displayed after the evaluation
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578
579=item C<$onetimeDumpDepth> - how deep C<dumpit()> should go when dumping results
580
581=back
582
583The following variables are altered by C<DB::eval()> during its execution. They
b570d64b 584are "stacked" via C<local()>, enabling recursive calls to C<DB::eval()>.
69893cff
RGS
585
586=over 4
587
588=item C<@res> - used to capture output from actual C<eval>.
589
590=item C<$otrace> - saved value of C<$trace>.
591
b570d64b 592=item C<$osingle> - saved value of C<$single>.
69893cff
RGS
593
594=item C<$od> - saved value of C<$^D>.
595
596=item C<$saved[0]> - saved value of C<$@>.
597
b570d64b 598=item $\ - for output of C<$@> if there is an evaluation error.
69893cff
RGS
599
600=back
601
602=head3 The problem of lexicals
603
604The context of C<DB::eval()> presents us with some problems. Obviously,
605we want to be 'sandboxed' away from the debugger's internals when we do
606the eval, but we need some way to control how punctuation variables and
b570d64b 607debugger globals are used.
69893cff
RGS
608
609We can't use local, because the code inside C<DB::eval> can see localized
610variables; and we can't use C<my> either for the same reason. The code
611in this routine compromises and uses C<my>.
612
613After this routine is over, we don't have user code executing in the debugger's
614context, so we can use C<my> freely.
615
616=cut
617
618############################################## Begin lexical danger zone
619
620# 'my' variables used here could leak into (that is, be visible in)
621# the context that the code being evaluated is executing in. This means that
622# the code could modify the debugger's variables.
623#
624# Fiddling with the debugger's context could be Bad. We insulate things as
625# much as we can.
626
6b24a4b7
SF
627use vars qw(
628 @args
629 %break_on_load
630 @cmdfhs
631 $CommandSet
632 $CreateTTY
633 $DBGR
634 @dbline
635 $dbline
636 %dbline
637 $dieLevel
638 $evalarg
639 $filename
640 $frame
641 $hist
642 $histfile
643 $histsize
644 $ImmediateStop
645 $IN
646 $inhibit_exit
647 @ini_INC
648 $ini_warn
649 $line
650 $maxtrace
651 $od
652 $onetimeDump
653 $onetimedumpDepth
654 %option
655 @options
656 $osingle
657 $otrace
658 $OUT
659 $packname
660 $pager
661 $post
662 %postponed
663 $prc
664 $pre
665 $pretype
666 $psh
667 @RememberOnROptions
668 $remoteport
669 @res
670 $rl
671 @saved
672 $signal
673 $signalLevel
674 $single
675 $start
676 $sub
677 %sub
678 $subname
679 $term
680 $trace
681 $usercontext
682 $warnLevel
683 $window
684);
685
686# Used to save @ARGV and extract any debugger-related flags.
687use vars qw(@ARGS);
688
689# Used to prevent multiple entries to diesignal()
690# (if for instance diesignal() itself dies)
691use vars qw($panic);
692
693# Used to prevent the debugger from running nonstop
694# after a restart
695use vars qw($second_time);
696
697sub _calc_usercontext {
698 my ($package) = @_;
699
700 # Cancel strict completely for the evaluated code, so the code
701 # the user evaluates won't be affected by it. (Shlomi Fish)
702 return 'no strict; ($@, $!, $^E, $,, $/, $\, $^W) = @saved;'
703 . "package $package;"; # this won't let them modify, alas
704}
705
c1051fcf 706sub eval {
69893cff 707
c1051fcf 708 # 'my' would make it visible from user code
e22ea7cc 709 # but so does local! --tchrist
69893cff 710 # Remember: this localizes @DB::res, not @main::res.
c1051fcf
IZ
711 local @res;
712 {
e22ea7cc
RF
713
714 # Try to keep the user code from messing with us. Save these so that
715 # even if the eval'ed code changes them, we can put them back again.
716 # Needed because the user could refer directly to the debugger's
69893cff
RGS
717 # package globals (and any 'my' variables in this containing scope)
718 # inside the eval(), and we want to try to stay safe.
e22ea7cc 719 local $otrace = $trace;
69893cff
RGS
720 local $osingle = $single;
721 local $od = $^D;
722
723 # Untaint the incoming eval() argument.
724 { ($evalarg) = $evalarg =~ /(.*)/s; }
725
e22ea7cc 726 # $usercontext built in DB::DB near the comment
69893cff
RGS
727 # "set up the context for DB::eval ..."
728 # Evaluate and save any results.
e22ea7cc 729 @res = eval "$usercontext $evalarg;\n"; # '\n' for nice recursive debug
69893cff
RGS
730
731 # Restore those old values.
732 $trace = $otrace;
733 $single = $osingle;
734 $^D = $od;
c1051fcf 735 }
69893cff
RGS
736
737 # Save the current value of $@, and preserve it in the debugger's copy
738 # of the saved precious globals.
c1051fcf 739 my $at = $@;
69893cff
RGS
740
741 # Since we're only saving $@, we only have to localize the array element
742 # that it will be stored in.
e22ea7cc 743 local $saved[0]; # Preserve the old value of $@
c1051fcf 744 eval { &DB::save };
69893cff
RGS
745
746 # Now see whether we need to report an error back to the user.
c1051fcf 747 if ($at) {
69893cff
RGS
748 local $\ = '';
749 print $OUT $at;
750 }
751
752 # Display as required by the caller. $onetimeDump and $onetimedumpDepth
753 # are package globals.
754 elsif ($onetimeDump) {
e22ea7cc
RF
755 if ( $onetimeDump eq 'dump' ) {
756 local $option{dumpDepth} = $onetimedumpDepth
757 if defined $onetimedumpDepth;
758 dumpit( $OUT, \@res );
759 }
760 elsif ( $onetimeDump eq 'methods' ) {
761 methods( $res[0] );
762 }
69893cff 763 } ## end elsif ($onetimeDump)
c1051fcf 764 @res;
69893cff
RGS
765} ## end sub eval
766
767############################################## End lexical danger zone
c1051fcf 768
e22ea7cc
RF
769# After this point it is safe to introduce lexicals.
770# The code being debugged will be executing in its own context, and
69893cff 771# can't see the inside of the debugger.
d338d6fe 772#
e22ea7cc 773# However, one should not overdo it: leave as much control from outside as
69893cff
RGS
774# possible. If you make something a lexical, it's not going to be addressable
775# from outside the debugger even if you know its name.
776
d338d6fe
PP
777# This file is automatically included if you do perl -d.
778# It's probably not useful to include this yourself.
779#
e22ea7cc 780# Before venturing further into these twisty passages, it is
2f7e9187
MS
781# wise to read the perldebguts man page or risk the ire of dragons.
782#
69893cff
RGS
783# (It should be noted that perldebguts will tell you a lot about
784# the underlying mechanics of how the debugger interfaces into the
785# Perl interpreter, but not a lot about the debugger itself. The new
786# comments in this code try to address this problem.)
787
d338d6fe 788# Note that no subroutine call is possible until &DB::sub is defined
36477c24 789# (for subroutines defined outside of the package DB). In fact the same is
d338d6fe 790# true if $deep is not defined.
055fd3a9
GS
791
792# Enhanced by ilya@math.ohio-state.edu (Ilya Zakharevich)
055fd3a9
GS
793
794# modified Perl debugger, to be run from Emacs in perldb-mode
795# Ray Lischner (uunet!mntgfx!lisch) as of 5 Nov 1990
796# Johan Vromans -- upgrade to 4.0 pl 10
797# Ilya Zakharevich -- patches after 5.001 (and some before ;-)
6fae1ad7 798########################################################################
d338d6fe 799
69893cff
RGS
800=head1 DEBUGGER INITIALIZATION
801
802The debugger starts up in phases.
803
804=head2 BASIC SETUP
805
806First, it initializes the environment it wants to run in: turning off
807warnings during its own compilation, defining variables which it will need
808to avoid warnings later, setting itself up to not exit when the program
809terminates, and defaulting to printing return values for the C<r> command.
810
811=cut
812
eda6e075 813# Needed for the statement after exec():
69893cff
RGS
814#
815# This BEGIN block is simply used to switch off warnings during debugger
98dc9551 816# compilation. Probably it would be better practice to fix the warnings,
69893cff 817# but this is how it's done at the moment.
eda6e075 818
e22ea7cc
RF
819BEGIN {
820 $ini_warn = $^W;
821 $^W = 0;
822} # Switch compilation warnings off until another BEGIN.
d12a4851 823
69893cff
RGS
824local ($^W) = 0; # Switch run-time warnings off during init.
825
2cbb2ee1
RGS
826=head2 THREADS SUPPORT
827
828If we are running under a threaded Perl, we require threads and threads::shared
829if the environment variable C<PERL5DB_THREADED> is set, to enable proper
830threaded debugger control. C<-dt> can also be used to set this.
831
832Each new thread will be announced and the debugger prompt will always inform
833you of each new thread created. It will also indicate the thread id in which
834we are currently running within the prompt like this:
835
836 [tid] DB<$i>
837
838Where C<[tid]> is an integer thread id and C<$i> is the familiar debugger
839command prompt. The prompt will show: C<[0]> when running under threads, but
840not actually in a thread. C<[tid]> is consistent with C<gdb> usage.
841
842While running under threads, when you set or delete a breakpoint (etc.), this
b570d64b 843will apply to all threads, not just the currently running one. When you are
2cbb2ee1
RGS
844in a currently executing thread, you will stay there until it completes. With
845the current implementation it is not currently possible to hop from one thread
846to another.
847
848The C<e> and C<E> commands are currently fairly minimal - see C<h e> and C<h E>.
849
850Note that threading support was built into the debugger as of Perl version
851C<5.8.6> and debugger version C<1.2.8>.
852
853=cut
854
855BEGIN {
856 # ensure we can share our non-threaded variables or no-op
857 if ($ENV{PERL5DB_THREADED}) {
858 require threads;
859 require threads::shared;
860 import threads::shared qw(share);
861 $DBGR;
862 share(\$DBGR);
863 lock($DBGR);
864 print "Threads support enabled\n";
865 } else {
866 *lock = sub(*) {};
867 *share = sub(*) {};
868 }
869}
870
2218c045
SF
871# These variables control the execution of 'dumpvar.pl'.
872{
873 package dumpvar;
874 use vars qw(
875 $hashDepth
876 $arrayDepth
877 $dumpDBFiles
878 $dumpPackages
879 $quoteHighBit
880 $printUndef
881 $globPrint
882 $usageOnly
883 );
884}
69893cff 885
2218c045
SF
886# used to control die() reporting in diesignal()
887{
888 package Carp;
889 use vars qw($CarpLevel);
890}
d338d6fe 891
422c59bf 892# without threads, $filename is not defined until DB::DB is called
2cbb2ee1 893foreach my $k (keys (%INC)) {
fb4d8a6c 894 share(\$main::{'_<'.$filename}) if defined $filename;
2cbb2ee1
RGS
895};
896
54d04a52 897# Command-line + PERLLIB:
69893cff 898# Save the contents of @INC before they are modified elsewhere.
54d04a52
IZ
899@ini_INC = @INC;
900
69893cff
RGS
901# This was an attempt to clear out the previous values of various
902# trapped errors. Apparently it didn't help. XXX More info needed!
d338d6fe
PP
903# $prevwarn = $prevdie = $prevbus = $prevsegv = ''; # Does not help?!
904
69893cff
RGS
905# We set these variables to safe values. We don't want to blindly turn
906# off warnings, because other packages may still want them.
e22ea7cc
RF
907$trace = $signal = $single = 0; # Uninitialized warning suppression
908 # (local $^W cannot help - other packages!).
69893cff
RGS
909
910# Default to not exiting when program finishes; print the return
911# value when the 'r' command is used to return from a subroutine.
55497cff 912$inhibit_exit = $option{PrintRet} = 1;
d338d6fe 913
6b24a4b7
SF
914use vars qw($trace_to_depth);
915
5e2b42dd
SF
916# Default to 1E9 so it won't be limited to a certain recursion depth.
917$trace_to_depth = 1E9;
bdba49ad 918
69893cff
RGS
919=head1 OPTION PROCESSING
920
b570d64b
SF
921The debugger's options are actually spread out over the debugger itself and
922C<dumpvar.pl>; some of these are variables to be set, while others are
69893cff
RGS
923subs to be called with a value. To try to make this a little easier to
924manage, the debugger uses a few data structures to define what options
925are legal and how they are to be processed.
926
927First, the C<@options> array defines the I<names> of all the options that
928are to be accepted.
929
930=cut
931
932@options = qw(
5561b870 933 CommandSet HistFile HistSize
e22ea7cc
RF
934 hashDepth arrayDepth dumpDepth
935 DumpDBFiles DumpPackages DumpReused
936 compactDump veryCompact quote
937 HighBit undefPrint globPrint
938 PrintRet UsageOnly frame
939 AutoTrace TTY noTTY
940 ReadLine NonStop LineInfo
941 maxTraceLen recallCommand ShellBang
942 pager tkRunning ornaments
943 signalLevel warnLevel dieLevel
944 inhibit_exit ImmediateStop bareStringify
945 CreateTTY RemotePort windowSize
584420f0 946 DollarCaretP
e22ea7cc 947);
d12a4851 948
584420f0 949@RememberOnROptions = qw(DollarCaretP);
d12a4851 950
69893cff
RGS
951=pod
952
953Second, C<optionVars> lists the variables that each option uses to save its
954state.
955
956=cut
957
6b24a4b7
SF
958use vars qw(%optionVars);
959
69893cff 960%optionVars = (
e22ea7cc
RF
961 hashDepth => \$dumpvar::hashDepth,
962 arrayDepth => \$dumpvar::arrayDepth,
963 CommandSet => \$CommandSet,
964 DumpDBFiles => \$dumpvar::dumpDBFiles,
965 DumpPackages => \$dumpvar::dumpPackages,
966 DumpReused => \$dumpvar::dumpReused,
967 HighBit => \$dumpvar::quoteHighBit,
968 undefPrint => \$dumpvar::printUndef,
969 globPrint => \$dumpvar::globPrint,
970 UsageOnly => \$dumpvar::usageOnly,
971 CreateTTY => \$CreateTTY,
972 bareStringify => \$dumpvar::bareStringify,
973 frame => \$frame,
974 AutoTrace => \$trace,
975 inhibit_exit => \$inhibit_exit,
976 maxTraceLen => \$maxtrace,
977 ImmediateStop => \$ImmediateStop,
978 RemotePort => \$remoteport,
979 windowSize => \$window,
5561b870
AK
980 HistFile => \$histfile,
981 HistSize => \$histsize,
69893cff
RGS
982);
983
984=pod
985
986Third, C<%optionAction> defines the subroutine to be called to process each
987option.
988
b570d64b 989=cut
69893cff 990
6b24a4b7
SF
991use vars qw(%optionAction);
992
69893cff
RGS
993%optionAction = (
994 compactDump => \&dumpvar::compactDump,
995 veryCompact => \&dumpvar::veryCompact,
996 quote => \&dumpvar::quote,
997 TTY => \&TTY,
998 noTTY => \&noTTY,
999 ReadLine => \&ReadLine,
1000 NonStop => \&NonStop,
1001 LineInfo => \&LineInfo,
1002 recallCommand => \&recallCommand,
1003 ShellBang => \&shellBang,
1004 pager => \&pager,
1005 signalLevel => \&signalLevel,
1006 warnLevel => \&warnLevel,
1007 dieLevel => \&dieLevel,
1008 tkRunning => \&tkRunning,
1009 ornaments => \&ornaments,
1010 RemotePort => \&RemotePort,
1011 DollarCaretP => \&DollarCaretP,
d12a4851
JH
1012);
1013
69893cff
RGS
1014=pod
1015
1016Last, the C<%optionRequire> notes modules that must be C<require>d if an
1017option is used.
1018
1019=cut
d338d6fe 1020
69893cff
RGS
1021# Note that this list is not complete: several options not listed here
1022# actually require that dumpvar.pl be loaded for them to work, but are
1023# not in the table. A subsequent patch will correct this problem; for
1024# the moment, we're just recommenting, and we are NOT going to change
1025# function.
6b24a4b7
SF
1026use vars qw(%optionRequire);
1027
eda6e075 1028%optionRequire = (
69893cff
RGS
1029 compactDump => 'dumpvar.pl',
1030 veryCompact => 'dumpvar.pl',
1031 quote => 'dumpvar.pl',
e22ea7cc 1032);
69893cff
RGS
1033
1034=pod
1035
1036There are a number of initialization-related variables which can be set
1037by putting code to set them in a BEGIN block in the C<PERL5DB> environment
1038variable. These are:
1039
1040=over 4
1041
1042=item C<$rl> - readline control XXX needs more explanation
1043
1044=item C<$warnLevel> - whether or not debugger takes over warning handling
1045
1046=item C<$dieLevel> - whether or not debugger takes over die handling
1047
1048=item C<$signalLevel> - whether or not debugger takes over signal handling
1049
1050=item C<$pre> - preprompt actions (array reference)
1051
1052=item C<$post> - postprompt actions (array reference)
1053
1054=item C<$pretype>
1055
1056=item C<$CreateTTY> - whether or not to create a new TTY for this debugger
1057
1058=item C<$CommandSet> - which command set to use (defaults to new, documented set)
1059
1060=back
1061
1062=cut
d338d6fe
PP
1063
1064# These guys may be defined in $ENV{PERL5DB} :
69893cff
RGS
1065$rl = 1 unless defined $rl;
1066$warnLevel = 1 unless defined $warnLevel;
1067$dieLevel = 1 unless defined $dieLevel;
1068$signalLevel = 1 unless defined $signalLevel;
1069$pre = [] unless defined $pre;
1070$post = [] unless defined $post;
1071$pretype = [] unless defined $pretype;
1072$CreateTTY = 3 unless defined $CreateTTY;
1073$CommandSet = '580' unless defined $CommandSet;
1074
2cbb2ee1
RGS
1075share($rl);
1076share($warnLevel);
1077share($dieLevel);
1078share($signalLevel);
1079share($pre);
1080share($post);
1081share($pretype);
1082share($rl);
1083share($CreateTTY);
1084share($CommandSet);
1085
69893cff
RGS
1086=pod
1087
1088The default C<die>, C<warn>, and C<signal> handlers are set up.
1089
1090=cut
055fd3a9 1091
d338d6fe
PP
1092warnLevel($warnLevel);
1093dieLevel($dieLevel);
1094signalLevel($signalLevel);
055fd3a9 1095
69893cff
RGS
1096=pod
1097
1098The pager to be used is needed next. We try to get it from the
5561b870 1099environment first. If it's not defined there, we try to find it in
69893cff
RGS
1100the Perl C<Config.pm>. If it's not there, we default to C<more>. We
1101then call the C<pager()> function to save the pager name.
1102
1103=cut
1104
1105# This routine makes sure $pager is set up so that '|' can use it.
4865a36d 1106pager(
e22ea7cc 1107
69893cff 1108 # If PAGER is defined in the environment, use it.
e22ea7cc
RF
1109 defined $ENV{PAGER}
1110 ? $ENV{PAGER}
69893cff
RGS
1111
1112 # If not, see if Config.pm defines it.
e22ea7cc
RF
1113 : eval { require Config }
1114 && defined $Config::Config{pager}
1115 ? $Config::Config{pager}
69893cff
RGS
1116
1117 # If not, fall back to 'more'.
e22ea7cc
RF
1118 : 'more'
1119 )
1120 unless defined $pager;
69893cff
RGS
1121
1122=pod
1123
1124We set up the command to be used to access the man pages, the command
be9a9b1d
AT
1125recall character (C<!> unless otherwise defined) and the shell escape
1126character (C<!> unless otherwise defined). Yes, these do conflict, and
69893cff
RGS
1127neither works in the debugger at the moment.
1128
1129=cut
1130
055fd3a9 1131setman();
69893cff
RGS
1132
1133# Set up defaults for command recall and shell escape (note:
1134# these currently don't work in linemode debugging).
2218c045
SF
1135recallCommand("!") unless defined $prc;
1136shellBang("!") unless defined $psh;
69893cff
RGS
1137
1138=pod
1139
1140We then set up the gigantic string containing the debugger help.
1141We also set the limit on the number of arguments we'll display during a
1142trace.
1143
1144=cut
1145
04e43a21 1146sethelp();
69893cff
RGS
1147
1148# If we didn't get a default for the length of eval/stack trace args,
1149# set it here.
1d06cb2d 1150$maxtrace = 400 unless defined $maxtrace;
69893cff
RGS
1151
1152=head2 SETTING UP THE DEBUGGER GREETING
1153
be9a9b1d 1154The debugger I<greeting> helps to inform the user how many debuggers are
69893cff
RGS
1155running, and whether the current debugger is the primary or a child.
1156
1157If we are the primary, we just hang onto our pid so we'll have it when
1158or if we start a child debugger. If we are a child, we'll set things up
1159so we'll have a unique greeting and so the parent will give us our own
1160TTY later.
1161
1162We save the current contents of the C<PERLDB_PIDS> environment variable
1163because we mess around with it. We'll also need to hang onto it because
1164we'll need it if we restart.
1165
1166Child debuggers make a label out of the current PID structure recorded in
1167PERLDB_PIDS plus the new PID. They also mark themselves as not having a TTY
1168yet so the parent will give them one later via C<resetterm()>.
1169
1170=cut
1171
e22ea7cc 1172# Save the current contents of the environment; we're about to
69893cff 1173# much with it. We'll need this if we have to restart.
6b24a4b7 1174use vars qw($ini_pids);
f1583d8f 1175$ini_pids = $ENV{PERLDB_PIDS};
69893cff 1176
6b24a4b7
SF
1177use vars qw ($pids $term_pid);
1178
e22ea7cc
RF
1179if ( defined $ENV{PERLDB_PIDS} ) {
1180
69893cff 1181 # We're a child. Make us a label out of the current PID structure
e22ea7cc 1182 # recorded in PERLDB_PIDS plus our (new) PID. Mark us as not having
69893cff 1183 # a term yet so the parent will give us one later via resetterm().
55f4245e
JM
1184
1185 my $env_pids = $ENV{PERLDB_PIDS};
1186 $pids = "[$env_pids]";
1187
1188 # Unless we are on OpenVMS, all programs under the DCL shell run under
1189 # the same PID.
1190
1191 if (($^O eq 'VMS') && ($env_pids =~ /\b$$\b/)) {
1192 $term_pid = $$;
1193 }
1194 else {
1195 $ENV{PERLDB_PIDS} .= "->$$";
1196 $term_pid = -1;
1197 }
1198
69893cff
RGS
1199} ## end if (defined $ENV{PERLDB_PIDS...
1200else {
e22ea7cc
RF
1201
1202 # We're the parent PID. Initialize PERLDB_PID in case we end up with a
69893cff
RGS
1203 # child debugger, and mark us as the parent, so we'll know to set up
1204 # more TTY's is we have to.
1205 $ENV{PERLDB_PIDS} = "$$";
619a0444 1206 $pids = "[pid=$$]";
e22ea7cc 1207 $term_pid = $$;
f1583d8f 1208}
69893cff 1209
6b24a4b7 1210use vars qw($pidprompt);
f1583d8f 1211$pidprompt = '';
69893cff
RGS
1212
1213# Sets up $emacs as a synonym for $slave_editor.
6b24a4b7 1214use vars qw($slave_editor);
69893cff
RGS
1215*emacs = $slave_editor if $slave_editor; # May be used in afterinit()...
1216
1217=head2 READING THE RC FILE
1218
b570d64b 1219The debugger will read a file of initialization options if supplied. If
69893cff
RGS
1220running interactively, this is C<.perldb>; if not, it's C<perldb.ini>.
1221
b570d64b 1222=cut
69893cff
RGS
1223
1224# As noted, this test really doesn't check accurately that the debugger
1225# is running at a terminal or not.
d338d6fe 1226
6b24a4b7 1227use vars qw($rcfile);
fb4d8a6c
SF
1228{
1229 my $dev_tty = (($^O eq 'VMS') ? 'TT:' : '/dev/tty');
1230 # this is the wrong metric!
1231 $rcfile = ((-e $dev_tty) ? ".perldb" : "perldb.ini");
d338d6fe
PP
1232}
1233
69893cff
RGS
1234=pod
1235
1236The debugger does a safety test of the file to be read. It must be owned
1237either by the current user or root, and must only be writable by the owner.
1238
1239=cut
1240
1241# This wraps a safety test around "do" to read and evaluate the init file.
1242#
055fd3a9
GS
1243# This isn't really safe, because there's a race
1244# between checking and opening. The solution is to
1245# open and fstat the handle, but then you have to read and
1246# eval the contents. But then the silly thing gets
69893cff
RGS
1247# your lexical scope, which is unfortunate at best.
1248sub safe_do {
055fd3a9
GS
1249 my $file = shift;
1250
1251 # Just exactly what part of the word "CORE::" don't you understand?
69893cff
RGS
1252 local $SIG{__WARN__};
1253 local $SIG{__DIE__};
055fd3a9 1254
e22ea7cc 1255 unless ( is_safe_file($file) ) {
69893cff 1256 CORE::warn <<EO_GRIPE;
055fd3a9 1257perldb: Must not source insecure rcfile $file.
b570d64b 1258 You or the superuser must be the owner, and it must not
69893cff 1259 be writable by anyone but its owner.
055fd3a9 1260EO_GRIPE
69893cff
RGS
1261 return;
1262 } ## end unless (is_safe_file($file...
055fd3a9
GS
1263
1264 do $file;
1265 CORE::warn("perldb: couldn't parse $file: $@") if $@;
69893cff 1266} ## end sub safe_do
055fd3a9 1267
69893cff
RGS
1268# This is the safety test itself.
1269#
055fd3a9
GS
1270# Verifies that owner is either real user or superuser and that no
1271# one but owner may write to it. This function is of limited use
1272# when called on a path instead of upon a handle, because there are
1273# no guarantees that filename (by dirent) whose file (by ino) is
e22ea7cc 1274# eventually accessed is the same as the one tested.
055fd3a9
GS
1275# Assumes that the file's existence is not in doubt.
1276sub is_safe_file {
1277 my $path = shift;
69893cff 1278 stat($path) || return; # mysteriously vaporized
e22ea7cc 1279 my ( $dev, $ino, $mode, $nlink, $uid, $gid ) = stat(_);
055fd3a9
GS
1280
1281 return 0 if $uid != 0 && $uid != $<;
1282 return 0 if $mode & 022;
1283 return 1;
69893cff 1284} ## end sub is_safe_file
055fd3a9 1285
69893cff 1286# If the rcfile (whichever one we decided was the right one to read)
e22ea7cc
RF
1287# exists, we safely do it.
1288if ( -f $rcfile ) {
055fd3a9 1289 safe_do("./$rcfile");
69893cff 1290}
e22ea7cc 1291
69893cff 1292# If there isn't one here, try the user's home directory.
e22ea7cc 1293elsif ( defined $ENV{HOME} && -f "$ENV{HOME}/$rcfile" ) {
055fd3a9
GS
1294 safe_do("$ENV{HOME}/$rcfile");
1295}
e22ea7cc 1296
69893cff 1297# Else try the login directory.
e22ea7cc 1298elsif ( defined $ENV{LOGDIR} && -f "$ENV{LOGDIR}/$rcfile" ) {
055fd3a9 1299 safe_do("$ENV{LOGDIR}/$rcfile");
d338d6fe
PP
1300}
1301
69893cff 1302# If the PERLDB_OPTS variable has options in it, parse those out next.
e22ea7cc
RF
1303if ( defined $ENV{PERLDB_OPTS} ) {
1304 parse_options( $ENV{PERLDB_OPTS} );
d338d6fe
PP
1305}
1306
69893cff
RGS
1307=pod
1308
1309The last thing we do during initialization is determine which subroutine is
1310to be used to obtain a new terminal when a new debugger is started. Right now,
b0b54b5e 1311the debugger only handles TCP sockets, X11, OS/2, amd Mac OS X
11653f7f 1312(darwin).
69893cff
RGS
1313
1314=cut
1315
1316# Set up the get_fork_TTY subroutine to be aliased to the proper routine.
1317# Works if you're running an xterm or xterm-like window, or you're on
6fae1ad7
RF
1318# OS/2, or on Mac OS X. This may need some expansion.
1319
1320if (not defined &get_fork_TTY) # only if no routine exists
69893cff 1321{
b570d64b 1322 if ( defined $remoteport ) {
11653f7f
JJ
1323 # Expect an inetd-like server
1324 *get_fork_TTY = \&socket_get_fork_TTY; # to listen to us
1325 }
1326 elsif (defined $ENV{TERM} # If we know what kind
6fae1ad7
RF
1327 # of terminal this is,
1328 and $ENV{TERM} eq 'xterm' # and it's an xterm,
1329 and defined $ENV{DISPLAY} # and what display it's on,
1330 )
1331 {
1332 *get_fork_TTY = \&xterm_get_fork_TTY; # use the xterm version
1333 }
1334 elsif ( $^O eq 'os2' ) { # If this is OS/2,
1335 *get_fork_TTY = \&os2_get_fork_TTY; # use the OS/2 version
1336 }
1337 elsif ( $^O eq 'darwin' # If this is Mac OS X
1338 and defined $ENV{TERM_PROGRAM} # and we're running inside
1339 and $ENV{TERM_PROGRAM}
1340 eq 'Apple_Terminal' # Terminal.app
1341 )
1342 {
1343 *get_fork_TTY = \&macosx_get_fork_TTY; # use the Mac OS X version
1344 }
69893cff 1345} ## end if (not defined &get_fork_TTY...
e22ea7cc 1346
dbb46cec
DQ
1347# untaint $^O, which may have been tainted by the last statement.
1348# see bug [perl #24674]
e22ea7cc
RF
1349$^O =~ m/^(.*)\z/;
1350$^O = $1;
f1583d8f 1351
d12a4851 1352# Here begin the unreadable code. It needs fixing.
055fd3a9 1353
69893cff
RGS
1354=head2 RESTART PROCESSING
1355
1356This section handles the restart command. When the C<R> command is invoked, it
1357tries to capture all of the state it can into environment variables, and
1358then sets C<PERLDB_RESTART>. When we start executing again, we check to see
1359if C<PERLDB_RESTART> is there; if so, we reload all the information that
1360the R command stuffed into the environment variables.
1361
b570d64b 1362 PERLDB_RESTART - flag only, contains no restart data itself.
69893cff
RGS
1363 PERLDB_HIST - command history, if it's available
1364 PERLDB_ON_LOAD - breakpoints set by the rc file
1365 PERLDB_POSTPONE - subs that have been loaded/not executed, and have actions
1366 PERLDB_VISITED - files that had breakpoints
1367 PERLDB_FILE_... - breakpoints for a file
1368 PERLDB_OPT - active options
1369 PERLDB_INC - the original @INC
1370 PERLDB_PRETYPE - preprompt debugger actions
1371 PERLDB_PRE - preprompt Perl code
1372 PERLDB_POST - post-prompt Perl code
1373 PERLDB_TYPEAHEAD - typeahead captured by readline()
1374
1375We chug through all these variables and plug the values saved in them
1376back into the appropriate spots in the debugger.
1377
1378=cut
1379
6b24a4b7
SF
1380use vars qw(@hist @truehist %postponed_file @typeahead);
1381
e22ea7cc
RF
1382if ( exists $ENV{PERLDB_RESTART} ) {
1383
69893cff 1384 # We're restarting, so we don't need the flag that says to restart anymore.
e22ea7cc
RF
1385 delete $ENV{PERLDB_RESTART};
1386
1387 # $restart = 1;
1388 @hist = get_list('PERLDB_HIST');
1389 %break_on_load = get_list("PERLDB_ON_LOAD");
1390 %postponed = get_list("PERLDB_POSTPONE");
69893cff 1391
2cbb2ee1
RGS
1392 share(@hist);
1393 share(@truehist);
1394 share(%break_on_load);
1395 share(%postponed);
1396
69893cff 1397 # restore breakpoints/actions
e22ea7cc 1398 my @had_breakpoints = get_list("PERLDB_VISITED");
bdba49ad
SF
1399 for my $file_idx ( 0 .. $#had_breakpoints ) {
1400 my $filename = $had_breakpoints[$file_idx];
1401 my %pf = get_list("PERLDB_FILE_$file_idx");
1402 $postponed_file{ $filename } = \%pf if %pf;
1403 my @lines = sort {$a <=> $b} keys(%pf);
1404 my @enabled_statuses = get_list("PERLDB_FILE_ENABLED_$file_idx");
1405 for my $line_idx (0 .. $#lines) {
1406 _set_breakpoint_enabled_status(
1407 $filename,
1408 $lines[$line_idx],
1409 ($enabled_statuses[$line_idx] ? 1 : ''),
1410 );
1411 }
e22ea7cc 1412 }
69893cff
RGS
1413
1414 # restore options
e22ea7cc
RF
1415 my %opt = get_list("PERLDB_OPT");
1416 my ( $opt, $val );
1417 while ( ( $opt, $val ) = each %opt ) {
1418 $val =~ s/[\\\']/\\$1/g;
1419 parse_options("$opt'$val'");
1420 }
69893cff
RGS
1421
1422 # restore original @INC
e22ea7cc
RF
1423 @INC = get_list("PERLDB_INC");
1424 @ini_INC = @INC;
1425
1426 # return pre/postprompt actions and typeahead buffer
1427 $pretype = [ get_list("PERLDB_PRETYPE") ];
1428 $pre = [ get_list("PERLDB_PRE") ];
1429 $post = [ get_list("PERLDB_POST") ];
1430 @typeahead = get_list( "PERLDB_TYPEAHEAD", @typeahead );
69893cff
RGS
1431} ## end if (exists $ENV{PERLDB_RESTART...
1432
1433=head2 SETTING UP THE TERMINAL
1434
1435Now, we'll decide how the debugger is going to interact with the user.
1436If there's no TTY, we set the debugger to run non-stop; there's not going
1437to be anyone there to enter commands.
1438
1439=cut
54d04a52 1440
6b24a4b7
SF
1441use vars qw($notty $runnonstop $console $tty $LINEINFO);
1442use vars qw($lineinfo $doccmd);
1443
d338d6fe 1444if ($notty) {
69893cff 1445 $runnonstop = 1;
2cbb2ee1 1446 share($runnonstop);
69893cff 1447}
d12a4851 1448
69893cff
RGS
1449=pod
1450
1451If there is a TTY, we have to determine who it belongs to before we can
1452proceed. If this is a slave editor or graphical debugger (denoted by
1453the first command-line switch being '-emacs'), we shift this off and
1454set C<$rl> to 0 (XXX ostensibly to do straight reads).
1455
1456=cut
1457
1458else {
e22ea7cc 1459
69893cff
RGS
1460 # Is Perl being run from a slave editor or graphical debugger?
1461 # If so, don't use readline, and set $slave_editor = 1.
e22ea7cc
RF
1462 $slave_editor =
1463 ( ( defined $main::ARGV[0] ) and ( $main::ARGV[0] eq '-emacs' ) );
1464 $rl = 0, shift(@main::ARGV) if $slave_editor;
1465
1466 #require Term::ReadLine;
d12a4851 1467
69893cff
RGS
1468=pod
1469
1470We then determine what the console should be on various systems:
1471
1472=over 4
1473
1474=item * Cygwin - We use C<stdin> instead of a separate device.
1475
1476=cut
1477
e22ea7cc
RF
1478 if ( $^O eq 'cygwin' ) {
1479
69893cff
RGS
1480 # /dev/tty is binary. use stdin for textmode
1481 undef $console;
1482 }
1483
1484=item * Unix - use C</dev/tty>.
1485
1486=cut
1487
e22ea7cc 1488 elsif ( -e "/dev/tty" ) {
69893cff
RGS
1489 $console = "/dev/tty";
1490 }
1491
1492=item * Windows or MSDOS - use C<con>.
1493
1494=cut
1495
e22ea7cc 1496 elsif ( $^O eq 'dos' or -e "con" or $^O eq 'MSWin32' ) {
69893cff
RGS
1497 $console = "con";
1498 }
1499
69893cff
RGS
1500=item * VMS - use C<sys$command>.
1501
1502=cut
1503
1504 else {
e22ea7cc 1505
69893cff
RGS
1506 # everything else is ...
1507 $console = "sys\$command";
d12a4851 1508 }
69893cff
RGS
1509
1510=pod
1511
1512=back
1513
1514Several other systems don't use a specific console. We C<undef $console>
1515for those (Windows using a slave editor/graphical debugger, NetWare, OS/2
1516with a slave editor, Epoc).
1517
1518=cut
d12a4851 1519
e22ea7cc
RF
1520 if ( ( $^O eq 'MSWin32' ) and ( $slave_editor or defined $ENV{EMACS} ) ) {
1521
69893cff 1522 # /dev/tty is binary. use stdin for textmode
e22ea7cc
RF
1523 $console = undef;
1524 }
1525
1526 if ( $^O eq 'NetWare' ) {
d12a4851 1527
69893cff
RGS
1528 # /dev/tty is binary. use stdin for textmode
1529 $console = undef;
1530 }
d12a4851 1531
69893cff
RGS
1532 # In OS/2, we need to use STDIN to get textmode too, even though
1533 # it pretty much looks like Unix otherwise.
e22ea7cc
RF
1534 if ( defined $ENV{OS2_SHELL} and ( $slave_editor or $ENV{WINDOWID} ) )
1535 { # In OS/2
1536 $console = undef;
1537 }
1538
1539 # EPOC also falls into the 'got to use STDIN' camp.
1540 if ( $^O eq 'epoc' ) {
1541 $console = undef;
1542 }
d12a4851 1543
69893cff
RGS
1544=pod
1545
1546If there is a TTY hanging around from a parent, we use that as the console.
1547
1548=cut
1549
e22ea7cc 1550 $console = $tty if defined $tty;
d12a4851 1551
b570d64b 1552=head2 SOCKET HANDLING
69893cff
RGS
1553
1554The debugger is capable of opening a socket and carrying out a debugging
1555session over the socket.
1556
1557If C<RemotePort> was defined in the options, the debugger assumes that it
1558should try to start a debugging session on that port. It builds the socket
1559and then tries to connect the input and output filehandles to it.
1560
1561=cut
1562
1563 # Handle socket stuff.
e22ea7cc
RF
1564
1565 if ( defined $remoteport ) {
1566
69893cff
RGS
1567 # If RemotePort was defined in the options, connect input and output
1568 # to the socket.
11653f7f 1569 $IN = $OUT = connect_remoteport();
69893cff
RGS
1570 } ## end if (defined $remoteport)
1571
1572=pod
1573
1574If no C<RemotePort> was defined, and we want to create a TTY on startup,
1575this is probably a situation where multiple debuggers are running (for example,
1576a backticked command that starts up another debugger). We create a new IN and
1577OUT filehandle, and do the necessary mojo to create a new TTY if we know how
1578and if we can.
1579
1580=cut
1581
1582 # Non-socket.
1583 else {
e22ea7cc 1584
69893cff
RGS
1585 # Two debuggers running (probably a system or a backtick that invokes
1586 # the debugger itself under the running one). create a new IN and OUT
e22ea7cc 1587 # filehandle, and do the necessary mojo to create a new tty if we
69893cff 1588 # know how, and we can.
e22ea7cc
RF
1589 create_IN_OUT(4) if $CreateTTY & 4;
1590 if ($console) {
1591
69893cff 1592 # If we have a console, check to see if there are separate ins and
cd1191f1 1593 # outs to open. (They are assumed identical if not.)
69893cff 1594
e22ea7cc
RF
1595 my ( $i, $o ) = split /,/, $console;
1596 $o = $i unless defined $o;
69893cff 1597
69893cff 1598 # read/write on in, or just read, or read on STDIN.
e22ea7cc
RF
1599 open( IN, "+<$i" )
1600 || open( IN, "<$i" )
1601 || open( IN, "<&STDIN" );
1602
69893cff
RGS
1603 # read/write/create/clobber out, or write/create/clobber out,
1604 # or merge with STDERR, or merge with STDOUT.
e22ea7cc
RF
1605 open( OUT, "+>$o" )
1606 || open( OUT, ">$o" )
1607 || open( OUT, ">&STDERR" )
1608 || open( OUT, ">&STDOUT" ); # so we don't dongle stdout
1609
1610 } ## end if ($console)
1611 elsif ( not defined $console ) {
1612
1613 # No console. Open STDIN.
1614 open( IN, "<&STDIN" );
1615
1616 # merge with STDERR, or with STDOUT.
1617 open( OUT, ">&STDERR" )
1618 || open( OUT, ">&STDOUT" ); # so we don't dongle stdout
1619 $console = 'STDIN/OUT';
69893cff
RGS
1620 } ## end elsif (not defined $console)
1621
1622 # Keep copies of the filehandles so that when the pager runs, it
1623 # can close standard input without clobbering ours.
e22ea7cc
RF
1624 $IN = \*IN, $OUT = \*OUT if $console or not defined $console;
1625 } ## end elsif (from if(defined $remoteport))
1626
1627 # Unbuffer DB::OUT. We need to see responses right away.
70c9432b 1628 $OUT->autoflush(1);
e22ea7cc
RF
1629
1630 # Line info goes to debugger output unless pointed elsewhere.
1631 # Pointing elsewhere makes it possible for slave editors to
1632 # keep track of file and position. We have both a filehandle
1633 # and a I/O description to keep track of.
1634 $LINEINFO = $OUT unless defined $LINEINFO;
1635 $lineinfo = $console unless defined $lineinfo;
2cbb2ee1 1636 # share($LINEINFO); # <- unable to share globs
b570d64b 1637 share($lineinfo); #
e22ea7cc 1638
69893cff
RGS
1639=pod
1640
1641To finish initialization, we show the debugger greeting,
1642and then call the C<afterinit()> subroutine if there is one.
1643
1644=cut
d12a4851 1645
e22ea7cc
RF
1646 # Show the debugger greeting.
1647 $header =~ s/.Header: ([^,]+),v(\s+\S+\s+\S+).*$/$1$2/;
1648 unless ($runnonstop) {
1649 local $\ = '';
1650 local $, = '';
1651 if ( $term_pid eq '-1' ) {
1652 print $OUT "\nDaughter DB session started...\n";
1653 }
1654 else {
1655 print $OUT "\nLoading DB routines from $header\n";
1656 print $OUT (
1657 "Editor support ",
1658 $slave_editor ? "enabled" : "available", ".\n"
1659 );
1660 print $OUT
1f874cb6 1661"\nEnter h or 'h h' for help, or '$doccmd perldebug' for more help.\n\n";
69893cff
RGS
1662 } ## end else [ if ($term_pid eq '-1')
1663 } ## end unless ($runnonstop)
1664} ## end else [ if ($notty)
1665
1666# XXX This looks like a bug to me.
1667# Why copy to @ARGS and then futz with @args?
d338d6fe 1668@ARGS = @ARGV;
6b24a4b7 1669# for (@args) {
69893cff
RGS
1670 # Make sure backslashes before single quotes are stripped out, and
1671 # keep args unless they are numeric (XXX why?)
e22ea7cc
RF
1672 # s/\'/\\\'/g; # removed while not justified understandably
1673 # s/(.*)/'$1'/ unless /^-?[\d.]+$/; # ditto
6b24a4b7 1674# }
d338d6fe 1675
e22ea7cc 1676# If there was an afterinit() sub defined, call it. It will get
69893cff 1677# executed in our scope, so it can fiddle with debugger globals.
e22ea7cc 1678if ( defined &afterinit ) { # May be defined in $rcfile
69893cff 1679 &afterinit();
d338d6fe 1680}
e22ea7cc 1681
69893cff 1682# Inform us about "Stack dump during die enabled ..." in dieLevel().
6b24a4b7
SF
1683use vars qw($I_m_init);
1684
43aed9ee
IZ
1685$I_m_init = 1;
1686
d338d6fe
PP
1687############################################################ Subroutines
1688
69893cff
RGS
1689=head1 SUBROUTINES
1690
1691=head2 DB
1692
1693This gigantic subroutine is the heart of the debugger. Called before every
1694statement, its job is to determine if a breakpoint has been reached, and
1695stop if so; read commands from the user, parse them, and execute
b468dcb6 1696them, and then send execution off to the next statement.
69893cff
RGS
1697
1698Note that the order in which the commands are processed is very important;
1699some commands earlier in the loop will actually alter the C<$cmd> variable
be9a9b1d 1700to create other commands to be executed later. This is all highly I<optimized>
69893cff
RGS
1701but can be confusing. Check the comments for each C<$cmd ... && do {}> to
1702see what's happening in any given command.
1703
1704=cut
1705
6b24a4b7
SF
1706use vars qw(
1707 $action
1708 %alias
1709 $cmd
1710 $doret
1711 $fall_off_end
1712 $file
1713 $filename_ini
1714 $finished
1715 %had_breakpoints
1716 $incr
1717 $laststep
1718 $level
1719 $max
1720 @old_watch
1721 $package
1722 $rc
1723 $sh
1724 @stack
1725 $stack_depth
1726 @to_watch
1727 $try
2c247e84 1728 $end
6b24a4b7
SF
1729);
1730
d338d6fe 1731sub DB {
69893cff 1732
2cbb2ee1
RGS
1733 # lock the debugger and get the thread id for the prompt
1734 lock($DBGR);
1735 my $tid;
6b24a4b7
SF
1736 my $position;
1737 my ($prefix, $after, $infix);
1738 my $pat;
6b24a4b7 1739
2cbb2ee1 1740 if ($ENV{PERL5DB_THREADED}) {
878090d5 1741 $tid = eval { "[".threads->tid."]" };
2cbb2ee1
RGS
1742 }
1743
69893cff 1744 # Check for whether we should be running continuously or not.
36477c24 1745 # _After_ the perl program is compiled, $single is set to 1:
e22ea7cc
RF
1746 if ( $single and not $second_time++ ) {
1747
69893cff 1748 # Options say run non-stop. Run until we get an interrupt.
e22ea7cc
RF
1749 if ($runnonstop) { # Disable until signal
1750 # If there's any call stack in place, turn off single
1751 # stepping into subs throughout the stack.
2c247e84 1752 for my $i (0 .. $stack_depth) {
72d7d80d 1753 $stack[ $i ] &= ~1;
e22ea7cc
RF
1754 }
1755
69893cff 1756 # And we are now no longer in single-step mode.
e22ea7cc 1757 $single = 0;
69893cff
RGS
1758
1759 # If we simply returned at this point, we wouldn't get
1760 # the trace info. Fall on through.
e22ea7cc 1761 # return;
69893cff
RGS
1762 } ## end if ($runnonstop)
1763
e22ea7cc
RF
1764 elsif ($ImmediateStop) {
1765
1766 # We are supposed to stop here; XXX probably a break.
1767 $ImmediateStop = 0; # We've processed it; turn it off
1768 $signal = 1; # Simulate an interrupt to force
1769 # us into the command loop
69893cff
RGS
1770 }
1771 } ## end if ($single and not $second_time...
1772
1773 # If we're in single-step mode, or an interrupt (real or fake)
1774 # has occurred, turn off non-stop mode.
1775 $runnonstop = 0 if $single or $signal;
1776
1777 # Preserve current values of $@, $!, $^E, $,, $/, $\, $^W.
1778 # The code being debugged may have altered them.
d338d6fe 1779 &save;
69893cff
RGS
1780
1781 # Since DB::DB gets called after every line, we can use caller() to
1782 # figure out where we last were executing. Sneaky, eh? This works because
e22ea7cc 1783 # caller is returning all the extra information when called from the
69893cff 1784 # debugger.
e22ea7cc 1785 local ( $package, $filename, $line ) = caller;
6b24a4b7 1786 $filename_ini = $filename;
69893cff
RGS
1787
1788 # set up the context for DB::eval, so it can properly execute
1789 # code on behalf of the user. We add the package in so that the
1790 # code is eval'ed in the proper package (not in the debugger!).
6b24a4b7 1791 local $usercontext = _calc_usercontext($package);
69893cff
RGS
1792
1793 # Create an alias to the active file magical array to simplify
1794 # the code here.
e22ea7cc 1795 local (*dbline) = $main::{ '_<' . $filename };
aa057b67 1796
69893cff 1797 # Last line in the program.
55783941 1798 $max = $#dbline;
69893cff
RGS
1799
1800 # if we have something here, see if we should break.
e22ea7cc 1801 {
72d7d80d
SF
1802 # $stop is lexical and local to this block - $action on the other hand
1803 # is global.
1804 my $stop;
e22ea7cc 1805
72d7d80d
SF
1806 if ( $dbline{$line}
1807 && _is_breakpoint_enabled($filename, $line)
1808 && (( $stop, $action ) = split( /\0/, $dbline{$line} ) ) )
1809 {
e22ea7cc 1810
72d7d80d
SF
1811 # Stop if the stop criterion says to just stop.
1812 if ( $stop eq '1' ) {
1813 $signal |= 1;
5d5d9ea3 1814 }
72d7d80d
SF
1815
1816 # It's a conditional stop; eval it in the user's context and
1817 # see if we should stop. If so, remove the one-time sigil.
1818 elsif ($stop) {
1819 $evalarg = "\$DB::signal |= 1 if do {$stop}";
1820 &eval;
1821 # If the breakpoint is temporary, then delete its enabled status.
1822 if ($dbline{$line} =~ s/;9($|\0)/$1/) {
1823 _cancel_breakpoint_temp_enabled_status($filename, $line);
1824 }
1825 }
1826 } ## end if ($dbline{$line} && ...
1827 }
69893cff
RGS
1828
1829 # Preserve the current stop-or-not, and see if any of the W
1830 # (watch expressions) has changed.
36477c24 1831 my $was_signal = $signal;
69893cff
RGS
1832
1833 # If we have any watch expressions ...
e22ea7cc 1834 if ( $trace & 2 ) {
2c247e84 1835 for my $n (0 .. $#to_watch) {
e22ea7cc
RF
1836 $evalarg = $to_watch[$n];
1837 local $onetimeDump; # Tell DB::eval() to not output results
69893cff
RGS
1838
1839 # Fix context DB::eval() wants to return an array, but
1840 # we need a scalar here.
e22ea7cc
RF
1841 my ($val) = join( "', '", &eval );
1842 $val = ( ( defined $val ) ? "'$val'" : 'undef' );
69893cff
RGS
1843
1844 # Did it change?
e22ea7cc
RF
1845 if ( $val ne $old_watch[$n] ) {
1846
69893cff 1847 # Yep! Show the difference, and fake an interrupt.
e22ea7cc
RF
1848 $signal = 1;
1849 print $OUT <<EOP;
405ff068 1850Watchpoint $n:\t$to_watch[$n] changed:
69893cff
RGS
1851 old value:\t$old_watch[$n]
1852 new value:\t$val
6027b9a3 1853EOP
e22ea7cc 1854 $old_watch[$n] = $val;
69893cff 1855 } ## end if ($val ne $old_watch...
2c247e84 1856 } ## end for my $n (0 ..
69893cff
RGS
1857 } ## end if ($trace & 2)
1858
1859=head2 C<watchfunction()>
1860
1861C<watchfunction()> is a function that can be defined by the user; it is a
b570d64b 1862function which will be run on each entry to C<DB::DB>; it gets the
69893cff
RGS
1863current package, filename, and line as its parameters.
1864
b570d64b 1865The watchfunction can do anything it likes; it is executing in the
69893cff
RGS
1866debugger's context, so it has access to all of the debugger's internal
1867data structures and functions.
1868
1869C<watchfunction()> can control the debugger's actions. Any of the following
1870will cause the debugger to return control to the user's program after
1871C<watchfunction()> executes:
1872
b570d64b 1873=over 4
69893cff 1874
be9a9b1d
AT
1875=item *
1876
1877Returning a false value from the C<watchfunction()> itself.
1878
1879=item *
1880
1881Altering C<$single> to a false value.
1882
1883=item *
69893cff 1884
be9a9b1d 1885Altering C<$signal> to a false value.
69893cff 1886
be9a9b1d 1887=item *
69893cff 1888
be9a9b1d 1889Turning off the C<4> bit in C<$trace> (this also disables the
69893cff
RGS
1890check for C<watchfunction()>. This can be done with
1891
1892 $trace &= ~4;
1893
1894=back
1895
1896=cut
1897
e22ea7cc 1898 # If there's a user-defined DB::watchfunction, call it with the
69893cff
RGS
1899 # current package, filename, and line. The function executes in
1900 # the DB:: package.
e22ea7cc
RF
1901 if ( $trace & 4 ) { # User-installed watch
1902 return
1903 if watchfunction( $package, $filename, $line )
1904 and not $single
1905 and not $was_signal
1906 and not( $trace & ~4 );
69893cff
RGS
1907 } ## end if ($trace & 4)
1908
e22ea7cc 1909 # Pick up any alteration to $signal in the watchfunction, and
69893cff 1910 # turn off the signal now.
6027b9a3 1911 $was_signal = $signal;
69893cff
RGS
1912 $signal = 0;
1913
1914=head2 GETTING READY TO EXECUTE COMMANDS
1915
1916The debugger decides to take control if single-step mode is on, the
1917C<t> command was entered, or the user generated a signal. If the program
1918has fallen off the end, we set things up so that entering further commands
1919won't cause trouble, and we say that the program is over.
1920
1921=cut
1922
8dc67a69
SF
1923 # Make sure that we always print if asked for explicitly regardless
1924 # of $trace_to_depth .
1925 my $explicit_stop = ($single || $was_signal);
1926
69893cff
RGS
1927 # Check to see if we should grab control ($single true,
1928 # trace set appropriately, or we got a signal).
8dc67a69 1929 if ( $explicit_stop || ( $trace & 1 ) ) {
e22ea7cc 1930
69893cff 1931 # Yes, grab control.
e22ea7cc
RF
1932 if ($slave_editor) {
1933
69893cff 1934 # Tell the editor to update its position.
e22ea7cc
RF
1935 $position = "\032\032$filename:$line:0\n";
1936 print_lineinfo($position);
1937 }
69893cff
RGS
1938
1939=pod
1940
b570d64b 1941Special check: if we're in package C<DB::fake>, we've gone through the
69893cff
RGS
1942C<END> block at least once. We set up everything so that we can continue
1943to enter commands and have a valid context to be in.
1944
1945=cut
1946
e22ea7cc 1947 elsif ( $package eq 'DB::fake' ) {
69893cff 1948
69893cff 1949 # Fallen off the end already.
e22ea7cc
RF
1950 $term || &setterm;
1951 print_help(<<EOP);
405ff068 1952Debugged program terminated. Use B<q> to quit or B<R> to restart,
6b27b0a0 1953 use B<o> I<inhibit_exit> to avoid stopping after program termination,
b570d64b 1954 B<h q>, B<h R> or B<h o> to get additional info.
405ff068 1955EOP
e22ea7cc 1956
69893cff 1957 # Set the DB::eval context appropriately.
e22ea7cc 1958 $package = 'main';
6b24a4b7 1959 $usercontext = _calc_usercontext($package);
69893cff 1960 } ## end elsif ($package eq 'DB::fake')
e219e2fb 1961
69893cff 1962=pod
e219e2fb 1963
69893cff
RGS
1964If the program hasn't finished executing, we scan forward to the
1965next executable line, print that out, build the prompt from the file and line
b570d64b 1966number information, and print that.
e219e2fb 1967
69893cff
RGS
1968=cut
1969
e22ea7cc
RF
1970 else {
1971
8dc67a69 1972
69893cff
RGS
1973 # Still somewhere in the midst of execution. Set up the
1974 # debugger prompt.
1975 $sub =~ s/\'/::/; # Swap Perl 4 package separators (') to
e22ea7cc 1976 # Perl 5 ones (sorry, we don't print Klingon
69893cff
RGS
1977 #module names)
1978
6b24a4b7 1979 $prefix = $sub =~ /::/ ? "" : ($package . '::');
e22ea7cc
RF
1980 $prefix .= "$sub($filename:";
1981 $after = ( $dbline[$line] =~ /\n$/ ? '' : "\n" );
69893cff
RGS
1982
1983 # Break up the prompt if it's really long.
e22ea7cc
RF
1984 if ( length($prefix) > 30 ) {
1985 $position = "$prefix$line):\n$line:\t$dbline[$line]$after";
1986 $prefix = "";
1987 $infix = ":\t";
1988 }
1989 else {
1990 $infix = "):\t";
1991 $position = "$prefix$line$infix$dbline[$line]$after";
1992 }
69893cff
RGS
1993
1994 # Print current line info, indenting if necessary.
e22ea7cc
RF
1995 if ($frame) {
1996 print_lineinfo( ' ' x $stack_depth,
1997 "$line:\t$dbline[$line]$after" );
1998 }
1999 else {
8dc67a69 2000 depth_print_lineinfo($explicit_stop, $position);
e22ea7cc 2001 }
69893cff
RGS
2002
2003 # Scan forward, stopping at either the end or the next
2004 # unbreakable line.
72d7d80d 2005 for ( my $i = $line + 1 ; $i <= $max && $dbline[$i] == 0 ; ++$i )
e22ea7cc 2006 { #{ vi
69893cff
RGS
2007
2008 # Drop out on null statements, block closers, and comments.
2009 last if $dbline[$i] =~ /^\s*[\;\}\#\n]/;
2010
2011 # Drop out if the user interrupted us.
2012 last if $signal;
2013
2014 # Append a newline if the line doesn't have one. Can happen
2015 # in eval'ed text, for instance.
e22ea7cc 2016 $after = ( $dbline[$i] =~ /\n$/ ? '' : "\n" );
69893cff
RGS
2017
2018 # Next executable line.
6b24a4b7 2019 my $incr_pos = "$prefix$i$infix$dbline[$i]$after";
69893cff
RGS
2020 $position .= $incr_pos;
2021 if ($frame) {
e22ea7cc 2022
69893cff 2023 # Print it indented if tracing is on.
e22ea7cc
RF
2024 print_lineinfo( ' ' x $stack_depth,
2025 "$i:\t$dbline[$i]$after" );
69893cff
RGS
2026 }
2027 else {
8dc67a69 2028 depth_print_lineinfo($explicit_stop, $incr_pos);
69893cff 2029 }
72d7d80d 2030 } ## end for ($i = $line + 1 ; $i...
69893cff
RGS
2031 } ## end else [ if ($slave_editor)
2032 } ## end if ($single || ($trace...
2033
2034=pod
2035
2036If there's an action to be executed for the line we stopped at, execute it.
b570d64b 2037If there are any preprompt actions, execute those as well.
e219e2fb
RF
2038
2039=cut
2040
69893cff
RGS
2041 # If there's an action, do it now.
2042 $evalarg = $action, &eval if $action;
e219e2fb 2043
69893cff
RGS
2044 # Are we nested another level (e.g., did we evaluate a function
2045 # that had a breakpoint in it at the debugger prompt)?
e22ea7cc
RF
2046 if ( $single || $was_signal ) {
2047
69893cff 2048 # Yes, go down a level.
e22ea7cc 2049 local $level = $level + 1;
69893cff
RGS
2050
2051 # Do any pre-prompt actions.
e22ea7cc
RF
2052 foreach $evalarg (@$pre) {
2053 &eval;
2054 }
69893cff
RGS
2055
2056 # Complain about too much recursion if we passed the limit.
e22ea7cc 2057 print $OUT $stack_depth . " levels deep in subroutine calls!\n"
69893cff
RGS
2058 if $single & 4;
2059
2060 # The line we're currently on. Set $incr to -1 to stay here
2061 # until we get a command that tells us to advance.
e22ea7cc
RF
2062 $start = $line;
2063 $incr = -1; # for backward motion.
69893cff
RGS
2064
2065 # Tack preprompt debugger actions ahead of any actual input.
e22ea7cc 2066 @typeahead = ( @$pretype, @typeahead );
69893cff
RGS
2067
2068=head2 WHERE ARE WE?
2069
2070XXX Relocate this section?
2071
2072The debugger normally shows the line corresponding to the current line of
2073execution. Sometimes, though, we want to see the next line, or to move elsewhere
2074in the file. This is done via the C<$incr>, C<$start>, and C<$max> variables.
2075
be9a9b1d
AT
2076C<$incr> controls by how many lines the I<current> line should move forward
2077after a command is executed. If set to -1, this indicates that the I<current>
69893cff
RGS
2078line shouldn't change.
2079
be9a9b1d 2080C<$start> is the I<current> line. It is used for things like knowing where to
69893cff
RGS
2081move forwards or backwards from when doing an C<L> or C<-> command.
2082
2083C<$max> tells the debugger where the last line of the current file is. It's
2084used to terminate loops most often.
2085
2086=head2 THE COMMAND LOOP
2087
2088Most of C<DB::DB> is actually a command parsing and dispatch loop. It comes
2089in two parts:
2090
2091=over 4
2092
be9a9b1d
AT
2093=item *
2094
2095The outer part of the loop, starting at the C<CMD> label. This loop
69893cff
RGS
2096reads a command and then executes it.
2097
be9a9b1d
AT
2098=item *
2099
2100The inner part of the loop, starting at the C<PIPE> label. This part
69893cff
RGS
2101is wholly contained inside the C<CMD> block and only executes a command.
2102Used to handle commands running inside a pager.
2103
2104=back
2105
2106So why have two labels to restart the loop? Because sometimes, it's easier to
2107have a command I<generate> another command and then re-execute the loop to do
2108the new command. This is faster, but perhaps a bit more convoluted.
2109
2110=cut
2111
2112 # The big command dispatch loop. It keeps running until the
2113 # user yields up control again.
2114 #
2115 # If we have a terminal for input, and we get something back
2116 # from readline(), keep on processing.
6b24a4b7
SF
2117 my $piped;
2118 my $selected;
2119
e22ea7cc
RF
2120 CMD:
2121 while (
2122
69893cff 2123 # We have a terminal, or can get one ...
e22ea7cc
RF
2124 ( $term || &setterm ),
2125
69893cff 2126 # ... and it belogs to this PID or we get one for this PID ...
e22ea7cc
RF
2127 ( $term_pid == $$ or resetterm(1) ),
2128
69893cff 2129 # ... and we got a line of command input ...
e22ea7cc
RF
2130 defined(
2131 $cmd = &readline(
2cbb2ee1 2132 "$pidprompt $tid DB"
e22ea7cc
RF
2133 . ( '<' x $level )
2134 . ( $#hist + 1 )
2135 . ( '>' x $level ) . " "
69893cff
RGS
2136 )
2137 )
2138 )
2139 {
e22ea7cc 2140
2cbb2ee1 2141 share($cmd);
69893cff
RGS
2142 # ... try to execute the input as debugger commands.
2143
2144 # Don't stop running.
2145 $single = 0;
2146
2147 # No signal is active.
2148 $signal = 0;
2149
2150 # Handle continued commands (ending with \):
3d7a2a93 2151 if ($cmd =~ s/\\\z/\n/) {
e22ea7cc
RF
2152 $cmd .= &readline(" cont: ");
2153 redo CMD;
3d7a2a93 2154 }
69893cff
RGS
2155
2156=head4 The null command
2157
be9a9b1d 2158A newline entered by itself means I<re-execute the last command>. We grab the
69893cff
RGS
2159command out of C<$laststep> (where it was recorded previously), and copy it
2160back into C<$cmd> to be executed below. If there wasn't any previous command,
2161we'll do nothing below (no command will match). If there was, we also save it
2162in the command history and fall through to allow the command parsing to pick
2163it up.
2164
2165=cut
2166
2167 # Empty input means repeat the last command.
e22ea7cc
RF
2168 $cmd =~ /^$/ && ( $cmd = $laststep );
2169 chomp($cmd); # get rid of the annoying extra newline
2170 push( @hist, $cmd ) if length($cmd) > 1;
2171 push( @truehist, $cmd );
2cbb2ee1
RGS
2172 share(@hist);
2173 share(@truehist);
e22ea7cc
RF
2174
2175 # This is a restart point for commands that didn't arrive
2176 # via direct user input. It allows us to 'redo PIPE' to
2177 # re-execute command processing without reading a new command.
69893cff 2178 PIPE: {
e22ea7cc
RF
2179 $cmd =~ s/^\s+//s; # trim annoying leading whitespace
2180 $cmd =~ s/\s+$//s; # trim annoying trailing whitespace
6b24a4b7 2181 my ($i) = split( /\s+/, $cmd );
69893cff
RGS
2182
2183=head3 COMMAND ALIASES
2184
2185The debugger can create aliases for commands (these are stored in the
2186C<%alias> hash). Before a command is executed, the command loop looks it up
2187in the alias hash and substitutes the contents of the alias for the command,
2188completely replacing it.
2189
2190=cut
2191
2192 # See if there's an alias for the command, and set it up if so.
e22ea7cc
RF
2193 if ( $alias{$i} ) {
2194
69893cff
RGS
2195 # Squelch signal handling; we want to keep control here
2196 # if something goes loco during the alias eval.
2197 local $SIG{__DIE__};
2198 local $SIG{__WARN__};
2199
2200 # This is a command, so we eval it in the DEBUGGER's
2201 # scope! Otherwise, we can't see the special debugger
2202 # variables, or get to the debugger's subs. (Well, we
2203 # _could_, but why make it even more complicated?)
2204 eval "\$cmd =~ $alias{$i}";
2205 if ($@) {
2206 local $\ = '';
1f874cb6 2207 print $OUT "Couldn't evaluate '$i' alias: $@";
69893cff
RGS
2208 next CMD;
2209 }
2210 } ## end if ($alias{$i})
2211
2212=head3 MAIN-LINE COMMANDS
2213
2214All of these commands work up to and after the program being debugged has
b570d64b 2215terminated.
69893cff
RGS
2216
2217=head4 C<q> - quit
2218
b570d64b 2219Quit the debugger. This entails setting the C<$fall_off_end> flag, so we don't
69893cff
RGS
2220try to execute further, cleaning any restart-related stuff out of the
2221environment, and executing with the last value of C<$?>.
2222
2223=cut
2224
3d7a2a93 2225 if ($cmd eq 'q') {
69893cff
RGS
2226 $fall_off_end = 1;
2227 clean_ENV();
2228 exit $?;
3d7a2a93 2229 }
69893cff 2230
611272bb 2231=head4 C<t> - trace [n]
69893cff
RGS
2232
2233Turn tracing on or off. Inverts the appropriate bit in C<$trace> (q.v.).
611272bb 2234If level is specified, set C<$trace_to_depth>.
69893cff
RGS
2235
2236=cut
2237
3d7a2a93 2238 if (my ($levels) = $cmd =~ /\At(?:\s+(\d+))?\z/) {
e22ea7cc
RF
2239 $trace ^= 1;
2240 local $\ = '';
611272bb 2241 $trace_to_depth = $levels ? $stack_depth + $levels : 1E9;
e22ea7cc 2242 print $OUT "Trace = "
611272bb
PS
2243 . ( ( $trace & 1 )
2244 ? ( $levels ? "on (to level $trace_to_depth)" : "on" )
2245 : "off" ) . "\n";
e22ea7cc 2246 next CMD;
3d7a2a93 2247 }
69893cff
RGS
2248
2249=head4 C<S> - list subroutines matching/not matching a pattern
2250
2251Walks through C<%sub>, checking to see whether or not to print the name.
2252
2253=cut
2254
826b9a2e
SF
2255 if (my ($print_all_subs, $should_reverse, $Spatt)
2256 = $cmd =~ /\AS(\s+(!)?(.+))?\z/) {
2257 # $Spatt is the pattern (if any) to use.
2258 # Reverse scan?
2259 my $Srev = defined $should_reverse;
2260 # No args - print all subs.
2261 my $Snocheck = !defined $print_all_subs;
69893cff
RGS
2262
2263 # Need to make these sane here.
e22ea7cc
RF
2264 local $\ = '';
2265 local $, = '';
69893cff
RGS
2266
2267 # Search through the debugger's magical hash of subs.
2268 # If $nocheck is true, just print the sub name.
2269 # Otherwise, check it against the pattern. We then use
2270 # the XOR trick to reverse the condition as required.
e22ea7cc
RF
2271 foreach $subname ( sort( keys %sub ) ) {
2272 if ( $Snocheck or $Srev ^ ( $subname =~ /$Spatt/ ) ) {
2273 print $OUT $subname, "\n";
2274 }
2275 }
2276 next CMD;
826b9a2e 2277 }
69893cff
RGS
2278
2279=head4 C<X> - list variables in current package
2280
b570d64b 2281Since the C<V> command actually processes this, just change this to the
69893cff
RGS
2282appropriate C<V> command and fall through.
2283
2284=cut
2285
e22ea7cc 2286 $cmd =~ s/^X\b/V $package/;
69893cff
RGS
2287
2288=head4 C<V> - list variables
2289
b570d64b 2290Uses C<dumpvar.pl> to dump out the current values for selected variables.
69893cff
RGS
2291
2292=cut
2293
2294 # Bare V commands get the currently-being-debugged package
2295 # added.
826b9a2e 2296 if ($cmd eq "V") {
e22ea7cc 2297 $cmd = "V $package";
826b9a2e 2298 }
69893cff
RGS
2299
2300 # V - show variables in package.
826b9a2e
SF
2301 if (my ($new_packname, $new_vars_str) =
2302 $cmd =~ /\AV\b\s*(\S+)\s*(.*)/) {
e22ea7cc 2303
69893cff
RGS
2304 # Save the currently selected filehandle and
2305 # force output to debugger's filehandle (dumpvar
2306 # just does "print" for output).
6b24a4b7 2307 my $savout = select($OUT);
69893cff
RGS
2308
2309 # Grab package name and variables to dump.
826b9a2e
SF
2310 $packname = $new_packname;
2311 my @vars = split( ' ', $new_vars_str );
69893cff
RGS
2312
2313 # If main::dumpvar isn't here, get it.
e81465be 2314 do 'dumpvar.pl' || die $@ unless defined &main::dumpvar;
e22ea7cc
RF
2315 if ( defined &main::dumpvar ) {
2316
69893cff
RGS
2317 # We got it. Turn off subroutine entry/exit messages
2318 # for the moment, along with return values.
e22ea7cc
RF
2319 local $frame = 0;
2320 local $doret = -2;
69893cff
RGS
2321
2322 # must detect sigpipe failures - not catching
2323 # then will cause the debugger to die.
2324 eval {
2325 &main::dumpvar(
2326 $packname,
2327 defined $option{dumpDepth}
e22ea7cc
RF
2328 ? $option{dumpDepth}
2329 : -1, # assume -1 unless specified
69893cff 2330 @vars
e22ea7cc
RF
2331 );
2332 };
2333
2334 # The die doesn't need to include the $@, because
2335 # it will automatically get propagated for us.
2336 if ($@) {
2337 die unless $@ =~ /dumpvar print failed/;
2338 }
2339 } ## end if (defined &main::dumpvar)
2340 else {
2341
2342 # Couldn't load dumpvar.
2343 print $OUT "dumpvar.pl not available.\n";
2344 }
69893cff 2345
69893cff 2346 # Restore the output filehandle, and go round again.
e22ea7cc
RF
2347 select($savout);
2348 next CMD;
826b9a2e 2349 }
69893cff
RGS
2350
2351=head4 C<x> - evaluate and print an expression
2352
2353Hands the expression off to C<DB::eval>, setting it up to print the value
2354via C<dumpvar.pl> instead of just printing it directly.
2355
2356=cut
2357
826b9a2e 2358 if ($cmd =~ s#\Ax\b# #) { # Remainder gets done by DB::eval()
e22ea7cc 2359 $onetimeDump = 'dump'; # main::dumpvar shows the output
69893cff
RGS
2360
2361 # handle special "x 3 blah" syntax XXX propagate
2362 # doc back to special variables.
826b9a2e 2363 if ( $cmd =~ s#\A\s*(\d+)(?=\s)# #) {
e22ea7cc
RF
2364 $onetimedumpDepth = $1;
2365 }
826b9a2e 2366 }
69893cff
RGS
2367
2368=head4 C<m> - print methods
2369
2370Just uses C<DB::methods> to determine what methods are available.
2371
2372=cut
2373
826b9a2e 2374 if ($cmd =~ s#\Am\s+([\w:]+)\s*\z# #) {
e22ea7cc
RF
2375 methods($1);
2376 next CMD;
826b9a2e 2377 }
69893cff
RGS
2378
2379 # m expr - set up DB::eval to do the work
826b9a2e 2380 if ($cmd =~ s#\Am\b# #) { # Rest gets done by DB::eval()
e22ea7cc 2381 $onetimeDump = 'methods'; # method output gets used there
826b9a2e 2382 }
69893cff
RGS
2383
2384=head4 C<f> - switch files
2385
2386=cut
2387
826b9a2e 2388 if (($file) = $cmd =~ /\Af\b\s*(.*)/) {
e22ea7cc 2389 $file =~ s/\s+$//;
69893cff
RGS
2390
2391 # help for no arguments (old-style was return from sub).
e22ea7cc
RF
2392 if ( !$file ) {
2393 print $OUT
2394 "The old f command is now the r command.\n"; # hint
2395 print $OUT "The new f command switches filenames.\n";
2396 next CMD;
2397 } ## end if (!$file)
69893cff
RGS
2398
2399 # if not in magic file list, try a close match.
e22ea7cc
RF
2400 if ( !defined $main::{ '_<' . $file } ) {
2401 if ( ($try) = grep( m#^_<.*$file#, keys %main:: ) ) {
2402 {
2403 $try = substr( $try, 2 );
1f874cb6 2404 print $OUT "Choosing $try matching '$file':\n";
e22ea7cc
RF
2405 $file = $try;
2406 }
2407 } ## end if (($try) = grep(m#^_<.*$file#...
2408 } ## end if (!defined $main::{ ...
69893cff
RGS
2409
2410 # If not successfully switched now, we failed.
e22ea7cc 2411 if ( !defined $main::{ '_<' . $file } ) {
1f874cb6 2412 print $OUT "No file matching '$file' is loaded.\n";
e22ea7cc
RF
2413 next CMD;
2414 }
69893cff 2415
e22ea7cc
RF
2416 # We switched, so switch the debugger internals around.
2417 elsif ( $file ne $filename ) {
2418 *dbline = $main::{ '_<' . $file };
2419 $max = $#dbline;
2420 $filename = $file;
2421 $start = 1;
2422 $cmd = "l";
2423 } ## end elsif ($file ne $filename)
2424
2425 # We didn't switch; say we didn't.
2426 else {
2427 print $OUT "Already in $file.\n";
2428 next CMD;
2429 }
826b9a2e 2430 }
69893cff
RGS
2431
2432=head4 C<.> - return to last-executed line.
2433
2434We set C<$incr> to -1 to indicate that the debugger shouldn't move ahead,
2435and then we look up the line in the magical C<%dbline> hash.
2436
2437=cut
2438
2439 # . command.
826b9a2e 2440 if ($cmd eq '.') {
e22ea7cc 2441 $incr = -1; # stay at current line
69893cff
RGS
2442
2443 # Reset everything to the old location.
e22ea7cc
RF
2444 $start = $line;
2445 $filename = $filename_ini;
2446 *dbline = $main::{ '_<' . $filename };
2447 $max = $#dbline;
69893cff
RGS
2448
2449 # Now where are we?
e22ea7cc
RF
2450 print_lineinfo($position);
2451 next CMD;
826b9a2e 2452 }
69893cff
RGS
2453
2454=head4 C<-> - back one window
2455
2456We change C<$start> to be one window back; if we go back past the first line,
2457we set it to be the first line. We ser C<$incr> to put us back at the
2458currently-executing line, and then put a C<l $start +> (list one window from
2459C<$start>) in C<$cmd> to be executed later.
2460
2461=cut
2462
2463 # - - back a window.
826b9a2e 2464 if ($cmd eq '-') {
e22ea7cc 2465
69893cff 2466 # back up by a window; go to 1 if back too far.
e22ea7cc
RF
2467 $start -= $incr + $window + 1;
2468 $start = 1 if $start <= 0;
2469 $incr = $window - 1;
69893cff
RGS
2470
2471 # Generate and execute a "l +" command (handled below).
e22ea7cc 2472 $cmd = 'l ' . ($start) . '+';
826b9a2e 2473 }
69893cff
RGS
2474
2475=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>, {, {{>
2476
2477In Perl 5.8.0, a realignment of the commands was done to fix up a number of
2478problems, most notably that the default case of several commands destroying
2479the user's work in setting watchpoints, actions, etc. We wanted, however, to
2480retain the old commands for those who were used to using them or who preferred
2481them. At this point, we check for the new commands and call C<cmd_wrapper> to
2482deal with them instead of processing them in-line.
2483
2484=cut
2485
2486 # All of these commands were remapped in perl 5.8.0;
e22ea7cc 2487 # we send them off to the secondary dispatcher (see below).
826b9a2e
SF
2488 if (my ($cmd_letter, $my_arg) = $cmd =~ /\A([aAbBeEhilLMoOPvwW]\b|[<>\{]{1,2})\s*(.*)/so) {
2489 &cmd_wrapper( $cmd_letter, $my_arg, $line );
e22ea7cc 2490 next CMD;
826b9a2e 2491 }
69893cff
RGS
2492
2493=head4 C<y> - List lexicals in higher scope
2494
826b9a2e 2495Uses C<PadWalker> to find the lexicals supplied as arguments in a scope
69893cff
RGS
2496above the current one and then displays then using C<dumpvar.pl>.
2497
2498=cut
2499
826b9a2e
SF
2500 if (my ($match_level, $match_vars)
2501 = $cmd =~ /^y(?:\s+(\d*)\s*(.*))?$/) {
69893cff
RGS
2502
2503 # See if we've got the necessary support.
2504 eval { require PadWalker; PadWalker->VERSION(0.08) }
2505 or &warn(
2506 $@ =~ /locate/
2507 ? "PadWalker module not found - please install\n"
2508 : $@
2509 )
2510 and next CMD;
2511
2512 # Load up dumpvar if we don't have it. If we can, that is.
e81465be 2513 do 'dumpvar.pl' || die $@ unless defined &main::dumpvar;
69893cff
RGS
2514 defined &main::dumpvar
2515 or print $OUT "dumpvar.pl not available.\n"
2516 and next CMD;
2517
2518 # Got all the modules we need. Find them and print them.
826b9a2e 2519 my @vars = split( ' ', $match_vars || '' );
69893cff
RGS
2520
2521 # Find the pad.
826b9a2e 2522 my $h = eval { PadWalker::peek_my( ( $match_level || 0 ) + 1 ) };
69893cff
RGS
2523
2524 # Oops. Can't find it.
2525 $@ and $@ =~ s/ at .*//, &warn($@), next CMD;
2526
2527 # Show the desired vars with dumplex().
2528 my $savout = select($OUT);
2529
2530 # Have dumplex dump the lexicals.
e22ea7cc 2531 dumpvar::dumplex( $_, $h->{$_},
69893cff 2532 defined $option{dumpDepth} ? $option{dumpDepth} : -1,
e22ea7cc
RF
2533 @vars )
2534 for sort keys %$h;
69893cff
RGS
2535 select($savout);
2536 next CMD;
826b9a2e 2537 }
69893cff
RGS
2538
2539=head3 COMMANDS NOT WORKING AFTER PROGRAM ENDS
2540
2541All of the commands below this point don't work after the program being
2542debugged has ended. All of them check to see if the program has ended; this
2543allows the commands to be relocated without worrying about a 'line of
2544demarcation' above which commands can be entered anytime, and below which
2545they can't.
2546
2547=head4 C<n> - single step, but don't trace down into subs
2548
2549Done by setting C<$single> to 2, which forces subs to execute straight through
be9a9b1d 2550when entered (see C<DB::sub>). We also save the C<n> command in C<$laststep>,
826b9a2e 2551so a null command knows what to re-execute.
69893cff
RGS
2552
2553=cut
2554
e22ea7cc 2555 # n - next
826b9a2e 2556 if ($cmd eq 'n') {
69893cff 2557 end_report(), next CMD if $finished and $level <= 1;
e22ea7cc 2558
69893cff
RGS
2559 # Single step, but don't enter subs.
2560 $single = 2;
e22ea7cc 2561
69893cff 2562 # Save for empty command (repeat last).
e22ea7cc
RF
2563 $laststep = $cmd;
2564 last CMD;
826b9a2e 2565 }
69893cff
RGS
2566
2567=head4 C<s> - single-step, entering subs
2568
826b9a2e 2569Sets C<$single> to 1, which causes C<DB::sub> to continue tracing inside
69893cff
RGS
2570subs. Also saves C<s> as C<$lastcmd>.
2571
2572=cut
2573
2574 # s - single step.
826b9a2e 2575 if ($cmd eq 's') {
e22ea7cc 2576
69893cff
RGS
2577 # Get out and restart the command loop if program
2578 # has finished.
e22ea7cc
RF
2579 end_report(), next CMD if $finished and $level <= 1;
2580
69893cff 2581 # Single step should enter subs.
e22ea7cc
RF
2582 $single = 1;
2583
69893cff 2584 # Save for empty command (repeat last).
e22ea7cc
RF
2585 $laststep = $cmd;
2586 last CMD;
826b9a2e 2587 }
69893cff
RGS
2588
2589=head4 C<c> - run continuously, setting an optional breakpoint
2590
2591Most of the code for this command is taken up with locating the optional
2592breakpoint, which is either a subroutine name or a line number. We set
2593the appropriate one-time-break in C<@dbline> and then turn off single-stepping
2594in this and all call levels above this one.
2595
2596=cut
2597
2598 # c - start continuous execution.
ef18ae63 2599 if (($i) = $cmd =~ m#\Ac\b\s*([\w:]*)\s*\z#) {
e22ea7cc 2600
69893cff
RGS
2601 # Hey, show's over. The debugged program finished
2602 # executing already.
2603 end_report(), next CMD if $finished and $level <= 1;
2604
2605 # Capture the place to put a one-time break.
ef18ae63 2606 $subname = $i;
69893cff 2607
e22ea7cc
RF
2608 # Probably not needed, since we finish an interactive
2609 # sub-session anyway...
2610 # local $filename = $filename;
2611 # local *dbline = *dbline; # XXX Would this work?!
69893cff
RGS
2612 #
2613 # The above question wonders if localizing the alias
2614 # to the magic array works or not. Since it's commented
2615 # out, we'll just leave that to speculation for now.
2616
2617 # If the "subname" isn't all digits, we'll assume it
2618 # is a subroutine name, and try to find it.
e22ea7cc
RF
2619 if ( $subname =~ /\D/ ) { # subroutine name
2620 # Qualify it to the current package unless it's
2621 # already qualified.
69893cff
RGS
2622 $subname = $package . "::" . $subname
2623 unless $subname =~ /::/;
e22ea7cc 2624
69893cff
RGS
2625 # find_sub will return "file:line_number" corresponding
2626 # to where the subroutine is defined; we call find_sub,
e22ea7cc 2627 # break up the return value, and assign it in one
69893cff 2628 # operation.
e22ea7cc 2629 ( $file, $i ) = ( find_sub($subname) =~ /^(.*):(.*)$/ );
69893cff
RGS
2630
2631 # Force the line number to be numeric.
e22ea7cc 2632 $i += 0;
69893cff
RGS
2633
2634 # If we got a line number, we found the sub.
e22ea7cc
RF
2635 if ($i) {
2636
69893cff
RGS
2637 # Switch all the debugger's internals around so
2638 # we're actually working with that file.
e22ea7cc
RF
2639 $filename = $file;
2640 *dbline = $main::{ '_<' . $filename };
2641
69893cff 2642 # Mark that there's a breakpoint in this file.
e22ea7cc
RF
2643 $had_breakpoints{$filename} |= 1;
2644
69893cff
RGS
2645 # Scan forward to the first executable line
2646 # after the 'sub whatever' line.
e22ea7cc
RF
2647 $max = $#dbline;
2648 ++$i while $dbline[$i] == 0 && $i < $max;
2649 } ## end if ($i)
69893cff
RGS
2650
2651 # We didn't find a sub by that name.
e22ea7cc
RF
2652 else {
2653 print $OUT "Subroutine $subname not found.\n";
2654 next CMD;
2655 }
2656 } ## end if ($subname =~ /\D/)
69893cff
RGS
2657
2658 # At this point, either the subname was all digits (an
2659 # absolute line-break request) or we've scanned through
2660 # the code following the definition of the sub, looking
2661 # for an executable, which we may or may not have found.
2662 #
2663 # If $i (which we set $subname from) is non-zero, we
e22ea7cc
RF
2664 # got a request to break at some line somewhere. On
2665 # one hand, if there wasn't any real subroutine name
2666 # involved, this will be a request to break in the current
2667 # file at the specified line, so we have to check to make
69893cff
RGS
2668 # sure that the line specified really is breakable.
2669 #
2670 # On the other hand, if there was a subname supplied, the
3c4b39be 2671 # preceding block has moved us to the proper file and
69893cff
RGS
2672 # location within that file, and then scanned forward
2673 # looking for the next executable line. We have to make
2674 # sure that one was found.
2675 #
2676 # On the gripping hand, we can't do anything unless the
2677 # current value of $i points to a valid breakable line.
2678 # Check that.
e22ea7cc
RF
2679 if ($i) {
2680
69893cff 2681 # Breakable?
e22ea7cc
RF
2682 if ( $dbline[$i] == 0 ) {
2683 print $OUT "Line $i not breakable.\n";
2684 next CMD;
2685 }
2686
69893cff 2687 # Yes. Set up the one-time-break sigil.
e22ea7cc 2688 $dbline{$i} =~ s/($|\0)/;9$1/; # add one-time-only b.p.
5d5d9ea3 2689 _enable_breakpoint_temp_enabled_status($filename, $i);
e22ea7cc 2690 } ## end if ($i)
69893cff
RGS
2691
2692 # Turn off stack tracing from here up.
2c247e84
SF
2693 for my $i (0 .. $stack_depth) {
2694 $stack[ $i ] &= ~1;
e22ea7cc
RF
2695 }
2696 last CMD;
ef18ae63 2697 }
69893cff
RGS
2698
2699=head4 C<r> - return from a subroutine
2700
2701For C<r> to work properly, the debugger has to stop execution again
2702immediately after the return is executed. This is done by forcing
2703single-stepping to be on in the call level above the current one. If
2704we are printing return values when a C<r> is executed, set C<$doret>
2705appropriately, and force us out of the command loop.
2706
2707=cut
2708
2709 # r - return from the current subroutine.
ef18ae63 2710 if ($cmd eq 'r') {
e22ea7cc 2711
98dc9551 2712 # Can't do anything if the program's over.
e22ea7cc
RF
2713 end_report(), next CMD if $finished and $level <= 1;
2714
69893cff 2715 # Turn on stack trace.
e22ea7cc
RF
2716 $stack[$stack_depth] |= 1;
2717
69893cff 2718 # Print return value unless the stack is empty.
e22ea7cc
RF
2719 $doret = $option{PrintRet} ? $stack_depth - 1 : -2;
2720 last CMD;
ef18ae63 2721 }
69893cff 2722
69893cff
RGS
2723=head4 C<T> - stack trace
2724
2725Just calls C<DB::print_trace>.
2726
2727=cut
2728
ef18ae63 2729 if ($cmd eq 'T') {
e22ea7cc
RF
2730 print_trace( $OUT, 1 ); # skip DB
2731 next CMD;
ef18ae63 2732 }
69893cff
RGS
2733
2734=head4 C<w> - List window around current line.
2735
2736Just calls C<DB::cmd_w>.
2737
2738=cut
2739
ef18ae63
SF
2740 if (my ($arg) = $cmd =~ /\Aw\b\s*(.*)/s) {
2741 &cmd_w( 'w', $arg );
2742 next CMD;
2743 }
69893cff
RGS
2744
2745=head4 C<W> - watch-expression processing.
2746
b570d64b 2747Just calls C<DB::cmd_W>.
69893cff
RGS
2748
2749=cut
2750
ef18ae63
SF
2751 if (my ($arg) = $cmd =~ /\AW\b\s*(.*)/s) {
2752 &cmd_W( 'W', $arg );
2753 next CMD;
2754 }
69893cff
RGS
2755
2756=head4 C</> - search forward for a string in the source
2757
ef18ae63 2758We take the argument and treat it as a pattern. If it turns out to be a
69893cff 2759bad one, we return the error we got from trying to C<eval> it and exit.
ef18ae63 2760If not, we create some code to do the search and C<eval> it so it can't
69893cff
RGS
2761mess us up.
2762
2763=cut
2764
ef18ae63
SF
2765 # The pattern as a string.
2766 use vars qw($inpat);
69893cff 2767
ef18ae63 2768 if (($inpat) = $cmd =~ m#\A/(.*)\z#) {
69893cff
RGS
2769
2770 # Remove the final slash.
e22ea7cc 2771 $inpat =~ s:([^\\])/$:$1:;
69893cff
RGS
2772
2773 # If the pattern isn't null ...
e22ea7cc 2774 if ( $inpat ne "" ) {
69893cff
RGS
2775
2776 # Turn of warn and die procesing for a bit.
e22ea7cc
RF
2777 local $SIG{__DIE__};
2778 local $SIG{__WARN__};
69893cff
RGS
2779
2780 # Create the pattern.
e22ea7cc
RF
2781 eval '$inpat =~ m' . "\a$inpat\a";
2782 if ( $@ ne "" ) {
2783
69893cff 2784 # Oops. Bad pattern. No biscuit.
e22ea7cc 2785 # Print the eval error and go back for more
69893cff 2786 # commands.
e22ea7cc
RF
2787 print $OUT "$@";
2788 next CMD;
2789 }
2790 $pat = $inpat;
2791 } ## end if ($inpat ne "")
69893cff
RGS
2792
2793 # Set up to stop on wrap-around.
e22ea7cc 2794 $end = $start;
69893cff
RGS
2795
2796 # Don't move off the current line.
e22ea7cc 2797 $incr = -1;
69893cff
RGS
2798
2799 # Done in eval so nothing breaks if the pattern
2800 # does something weird.
e22ea7cc
RF
2801 eval '
2802 for (;;) {
69893cff 2803 # Move ahead one line.
e22ea7cc 2804 ++$start;
69893cff
RGS
2805
2806 # Wrap if we pass the last line.
e22ea7cc 2807 $start = 1 if ($start > $max);
69893cff
RGS
2808
2809 # Stop if we have gotten back to this line again,
e22ea7cc 2810 last if ($start == $end);
69893cff
RGS
2811
2812 # A hit! (Note, though, that we are doing
2813 # case-insensitive matching. Maybe a qr//
2814 # expression would be better, so the user could
2815 # do case-sensitive matching if desired.
e22ea7cc
RF
2816 if ($dbline[$start] =~ m' . "\a$pat\a" . 'i) {
2817 if ($slave_editor) {
69893cff 2818 # Handle proper escaping in the slave.
e22ea7cc 2819 print $OUT "\032\032$filename:$start:0\n";
b570d64b 2820 }
e22ea7cc 2821 else {
69893cff 2822 # Just print the line normally.
e22ea7cc
RF
2823 print $OUT "$start:\t",$dbline[$start],"\n";
2824 }
69893cff 2825 # And quit since we found something.
e22ea7cc
RF
2826 last;
2827 }
2828 } ';
2829
69893cff 2830 # If we wrapped, there never was a match.
e22ea7cc
RF
2831 print $OUT "/$pat/: not found\n" if ( $start == $end );
2832 next CMD;
ef18ae63 2833 }
69893cff
RGS
2834
2835=head4 C<?> - search backward for a string in the source
2836
2837Same as for C</>, except the loop runs backwards.
2838
2839=cut
2840
2841 # ? - backward pattern search.
ef18ae63 2842 if (my ($inpat) = $cmd =~ m#\A\?(.*)\z#) {
69893cff
RGS
2843
2844 # Get the pattern, remove trailing question mark.
e22ea7cc 2845 $inpat =~ s:([^\\])\?$:$1:;
69893cff
RGS
2846
2847 # If we've got one ...
e22ea7cc 2848 if ( $inpat ne "" ) {
69893cff
RGS
2849
2850 # Turn off die & warn handlers.
e22ea7cc
RF
2851 local $SIG{__DIE__};
2852 local $SIG{__WARN__};
2853 eval '$inpat =~ m' . "\a$inpat\a";
2854
2855 if ( $@ ne "" ) {
2856
69893cff 2857 # Ouch. Not good. Print the error.
e22ea7cc
RF
2858 print $OUT $@;
2859 next CMD;
2860 }
2861 $pat = $inpat;
69893cff 2862 } ## end if ($inpat ne "")
e22ea7cc 2863
69893cff 2864 # Where we are now is where to stop after wraparound.
e22ea7cc 2865 $end = $start;
69893cff
RGS
2866
2867 # Don't move away from this line.
e22ea7cc 2868 $incr = -1;
69893cff
RGS
2869
2870 # Search inside the eval to prevent pattern badness
2871 # from killing us.
e22ea7cc
RF
2872 eval '
2873 for (;;) {
69893cff 2874 # Back up a line.
e22ea7cc 2875 --$start;
69893cff
RGS
2876
2877 # Wrap if we pass the first line.
e22ea7cc
RF
2878
2879 $start = $max if ($start <= 0);
69893cff
RGS
2880
2881 # Quit if we get back where we started,
e22ea7cc 2882 last if ($start == $end);
69893cff
RGS
2883
2884 # Match?
e22ea7cc
RF
2885 if ($dbline[$start] =~ m' . "\a$pat\a" . 'i) {
2886 if ($slave_editor) {
69893cff 2887 # Yep, follow slave editor requirements.
e22ea7cc 2888 print $OUT "\032\032$filename:$start:0\n";
b570d64b 2889 }
e22ea7cc 2890 else {
69893cff 2891 # Yep, just print normally.
e22ea7cc
RF
2892 print $OUT "$start:\t",$dbline[$start],"\n";
2893 }
69893cff
RGS
2894
2895 # Found, so done.
e22ea7cc
RF
2896 last;
2897 }
2898 } ';
2899
2900 # Say we failed if the loop never found anything,
2901 print $OUT "?$pat?: not found\n" if ( $start == $end );
2902 next CMD;
ef18ae63 2903 }
69893cff
RGS
2904
2905=head4 C<$rc> - Recall command
2906
2907Manages the commands in C<@hist> (which is created if C<Term::ReadLine> reports
2908that the terminal supports history). It find the the command required, puts it
2909into C<$cmd>, and redoes the loop to execute it.
2910
2911=cut
2912
e22ea7cc 2913 # $rc - recall command.
ef18ae63 2914 if (my ($minus, $arg) = $cmd =~ m#\A$rc+\s*(-)?(\d+)?\z#) {
69893cff
RGS
2915
2916 # No arguments, take one thing off history.
e22ea7cc 2917 pop(@hist) if length($cmd) > 1;
69893cff 2918
e22ea7cc 2919 # Relative (- found)?
69893cff 2920 # Y - index back from most recent (by 1 if bare minus)
e22ea7cc 2921 # N - go to that particular command slot or the last
69893cff 2922 # thing if nothing following.
ef18ae63 2923 $i = $minus ? ( $#hist - ( $arg || 1 ) ) : ( $arg || $#hist );
69893cff
RGS
2924
2925 # Pick out the command desired.
e22ea7cc 2926 $cmd = $hist[$i];
69893cff
RGS
2927
2928 # Print the command to be executed and restart the loop
2929 # with that command in the buffer.
e22ea7cc
RF
2930 print $OUT $cmd, "\n";
2931 redo CMD;
ef18ae63 2932 }
69893cff
RGS
2933
2934=head4 C<$sh$sh> - C<system()> command
2935
2936Calls the C<DB::system()> to handle the command. This keeps the C<STDIN> and
2937C<STDOUT> from getting messed up.
2938
2939=cut
2940
2941 # $sh$sh - run a shell command (if it's all ASCII).
2942 # Can't run shell commands with Unicode in the debugger, hmm.
ef18ae63 2943 if (my ($arg) = $cmd =~ m#\A$sh$sh\s*(.*)#ms) {
e22ea7cc 2944
69893cff 2945 # System it.
ef18ae63 2946 &system($arg);
e22ea7cc 2947 next CMD;
ef18ae63 2948 }
69893cff
RGS
2949
2950=head4 C<$rc I<pattern> $rc> - Search command history
2951
2952Another command to manipulate C<@hist>: this one searches it with a pattern.
be9a9b1d 2953If a command is found, it is placed in C<$cmd> and executed via C<redo>.
69893cff
RGS
2954
2955=cut
2956
e22ea7cc 2957 # $rc pattern $rc - find a command in the history.
ef18ae63 2958 if (my ($arg) = $cmd =~ /\A$rc([^$rc].*)\z/) {
e22ea7cc 2959
69893cff 2960 # Create the pattern to use.
ef18ae63 2961 $pat = "^$arg";
69893cff
RGS
2962
2963 # Toss off last entry if length is >1 (and it always is).
e22ea7cc 2964 pop(@hist) if length($cmd) > 1;
69893cff
RGS
2965
2966 # Look backward through the history.
72d7d80d 2967 for ( $i = $#hist ; $i ; --$i ) {
69893cff 2968 # Stop if we find it.
e22ea7cc
RF
2969 last if $hist[$i] =~ /$pat/;
2970 }
2971
2972 if ( !$i ) {
69893cff 2973
69893cff 2974 # Never found it.
e22ea7cc
RF
2975 print $OUT "No such command!\n\n";
2976 next CMD;
2977 }
69893cff
RGS
2978
2979 # Found it. Put it in the buffer, print it, and process it.
e22ea7cc
RF
2980 $cmd = $hist[$i];
2981 print $OUT $cmd, "\n";
2982 redo CMD;
ef18ae63 2983 }
69893cff 2984
ef18ae63 2985=head4 C<$sh> - Invoke a shell
69893cff
RGS
2986
2987Uses C<DB::system> to invoke a shell.
2988
2989=cut
2990
2991 # $sh - start a shell.
ef18ae63 2992 if ($cmd =~ /\A$sh\z/) {
e22ea7cc 2993
69893cff
RGS
2994 # Run the user's shell. If none defined, run Bourne.
2995 # We resume execution when the shell terminates.
e22ea7cc
RF
2996 &system( $ENV{SHELL} || "/bin/sh" );
2997 next CMD;
ef18ae63 2998 }
69893cff
RGS
2999
3000=head4 C<$sh I<command>> - Force execution of a command in a shell
3001
3002Like the above, but the command is passed to the shell. Again, we use
3003C<DB::system> to avoid problems with C<STDIN> and C<STDOUT>.
3004
3005=cut
3006
3007 # $sh command - start a shell and run a command in it.
ef18ae63 3008 if (my ($arg) = $cmd =~ m#\A$sh\s*(.*)#ms) {
e22ea7cc
RF
3009
3010 # XXX: using csh or tcsh destroys sigint retvals!
3011 #&system($1); # use this instead
69893cff
RGS
3012
3013 # use the user's shell, or Bourne if none defined.
ef18ae63 3014 &system( $ENV{SHELL} || "/bin/sh", "-c", $arg );
e22ea7cc 3015 next CMD;
ef18ae63 3016 }
69893cff
RGS
3017
3018=head4 C<H> - display commands in history
3019
3020Prints the contents of C<@hist> (if any).
3021
3022=cut
3023
ef18ae63 3024 if ($cmd =~ /\AH\b\s*\*/) {
7fddc82f
RF
3025 @hist = @truehist = ();
3026 print $OUT "History cleansed\n";
3027 next CMD;
ef18ae63 3028 }
e22ea7cc 3029
ef18ae63
SF
3030 if (my ($num)
3031 = $cmd =~ /\AH\b\s*(?:-(\d+))?/) {
e22ea7cc
RF
3032
3033 # Anything other than negative numbers is ignored by
69893cff 3034 # the (incorrect) pattern, so this test does nothing.
ef18ae63 3035 $end = $num ? ( $#hist - $num ) : 0;
69893cff
RGS
3036
3037 # Set to the minimum if less than zero.
e22ea7cc 3038 $hist = 0 if $hist < 0;
69893cff 3039
e22ea7cc 3040 # Start at the end of the array.
69893cff
RGS
3041 # Stay in while we're still above the ending value.
3042 # Tick back by one each time around the loop.
72d7d80d 3043 for ( $i = $#hist ; $i > $end ; $i-- ) {
69893cff
RGS
3044
3045 # Print the command unless it has no arguments.
e22ea7cc
RF
3046 print $OUT "$i: ", $hist[$i], "\n"
3047 unless $hist[$i] =~ /^.?$/;
3048 }
3049 next CMD;
ef18ae63 3050 }
69893cff
RGS
3051
3052=head4 C<man, doc, perldoc> - look up documentation
3053
3054Just calls C<runman()> to print the appropriate document.
3055
3056=cut
3057
e22ea7cc 3058 # man, perldoc, doc - show manual pages.
ef18ae63
SF
3059 if (my ($man_page)
3060 = $cmd =~ /\A(?:man|(?:perl)?doc)\b(?:\s+([^(]*))?\z/) {
3061 runman($man_page);
e22ea7cc 3062 next CMD;
ef18ae63 3063 }
69893cff
RGS
3064
3065=head4 C<p> - print
3066
3067Builds a C<print EXPR> expression in the C<$cmd>; this will get executed at
3068the bottom of the loop.
3069
3070=cut
3071
ef18ae63 3072 my $print_cmd = 'print {$DB::OUT} ';
69893cff 3073 # p - print (no args): print $_.
ef18ae63
SF
3074 if ($cmd eq 'p') {
3075 $cmd = $print_cmd . '$_';
3076 }
69893cff
RGS
3077
3078 # p - print the given expression.
ef18ae63 3079 $cmd =~ s/\Ap\b/$print_cmd /;
69893cff
RGS
3080
3081=head4 C<=> - define command alias
3082
3083Manipulates C<%alias> to add or list command aliases.
3084
3085=cut
3086
e22ea7cc 3087 # = - set up a command alias.
ef18ae63 3088 if ($cmd =~ s/\A=\s*//) {
e22ea7cc
RF
3089 my @keys;
3090 if ( length $cmd == 0 ) {
3091
69893cff 3092 # No args, get current aliases.
e22ea7cc
RF
3093 @keys = sort keys %alias;
3094 }
3095 elsif ( my ( $k, $v ) = ( $cmd =~ /^(\S+)\s+(\S.*)/ ) ) {
3096
69893cff
RGS
3097 # Creating a new alias. $k is alias name, $v is
3098 # alias value.
3099
e22ea7cc
RF
3100 # can't use $_ or kill //g state
3101 for my $x ( $k, $v ) {
3102
3103 # Escape "alarm" characters.
3104 $x =~ s/\a/\\a/g;
3105 }
69893cff
RGS
3106
3107 # Substitute key for value, using alarm chars
e22ea7cc 3108 # as separators (which is why we escaped them in
69893cff 3109 # the command).
e22ea7cc 3110 $alias{$k} = "s\a$k\a$v\a";
69893cff
RGS
3111
3112 # Turn off standard warn and die behavior.
e22ea7cc
RF
3113 local $SIG{__DIE__};
3114 local $SIG{__WARN__};
69893cff
RGS
3115
3116 # Is it valid Perl?
e22ea7cc
RF
3117 unless ( eval "sub { s\a$k\a$v\a }; 1" ) {
3118
69893cff 3119 # Nope. Bad alias. Say so and get out.
e22ea7cc
RF
3120 print $OUT "Can't alias $k to $v: $@\n";
3121 delete $alias{$k};
3122 next CMD;
3123 }
3124
69893cff 3125 # We'll only list the new one.
e22ea7cc 3126 @keys = ($k);
69893cff
RGS
3127 } ## end elsif (my ($k, $v) = ($cmd...
3128
3129 # The argument is the alias to list.
e22ea7cc
RF
3130 else {
3131 @keys = ($cmd);
3132 }
69893cff
RGS
3133
3134 # List aliases.
e22ea7cc
RF
3135 for my $k (@keys) {
3136
98dc9551 3137 # Messy metaquoting: Trim the substitution code off.
69893cff
RGS
3138 # We use control-G as the delimiter because it's not
3139 # likely to appear in the alias.
e22ea7cc
RF
3140 if ( ( my $v = $alias{$k} ) =~ s\as\a$k\a(.*)\a$\a1\a ) {
3141
69893cff 3142 # Print the alias.
e22ea7cc
RF
3143 print $OUT "$k\t= $1\n";
3144 }
3145 elsif ( defined $alias{$k} ) {
3146
69893cff 3147 # Couldn't trim it off; just print the alias code.
e22ea7cc
RF
3148 print $OUT "$k\t$alias{$k}\n";
3149 }
3150 else {
3151
69893cff 3152 # No such, dude.
e22ea7cc
RF
3153 print "No alias for $k\n";
3154 }
69893cff 3155 } ## end for my $k (@keys)
e22ea7cc 3156 next CMD;
ef18ae63 3157 }
69893cff
RGS
3158
3159=head4 C<source> - read commands from a file.
3160
3161Opens a lexical filehandle and stacks it on C<@cmdfhs>; C<DB::readline> will
3162pick it up.
3163
3164=cut
3165
e22ea7cc 3166 # source - read commands from a file (or pipe!) and execute.
ef18ae63
SF
3167 if (my ($sourced_fn) = $cmd =~ /\Asource\s+(.*\S)/) {
3168 if ( open my $fh, $sourced_fn ) {
e22ea7cc 3169
69893cff 3170 # Opened OK; stick it in the list of file handles.
e22ea7cc
RF
3171 push @cmdfhs, $fh;
3172 }
3173 else {
3174
3175 # Couldn't open it.
ef18ae63 3176 &warn("Can't execute '$sourced_fn': $!\n");
e22ea7cc
RF
3177 }
3178 next CMD;
ef18ae63 3179 }
69893cff 3180
ef18ae63
SF
3181 if (my ($which_cmd, $position)
3182 = $cmd =~ /^(enable|disable)\s+(\S+)\s*$/) {
e09195af
SF
3183
3184 my ($fn, $line_num);
3185 if ($position =~ m{\A\d+\z})
3186 {
3187 $fn = $filename;
3188 $line_num = $position;
3189 }
ef18ae63
SF
3190 elsif (my ($new_fn, $new_line_num)
3191 = $position =~ m{\A(.*):(\d+)\z}) {
3192 ($fn, $line_num) = ($new_fn, $new_line_num);
e09195af
SF
3193 }
3194 else
3195 {
3196 &warn("Wrong spec for enable/disable argument.\n");
3197 }
3198
3199 if (defined($fn)) {
3200 if (_has_breakpoint_data_ref($fn, $line_num)) {
3201 _set_breakpoint_enabled_status($fn, $line_num,
ef18ae63 3202 ($which_cmd eq 'enable' ? 1 : '')
e09195af
SF
3203 );
3204 }
3205 else {
3206 &warn("No breakpoint set at ${fn}:${line_num}\n");
3207 }
3208 }
3209
3210 next CMD;
ef18ae63 3211 }
e09195af 3212
69893cff
RGS
3213=head4 C<save> - send current history to a file
3214
3215Takes the complete history, (not the shrunken version you see with C<H>),
3216and saves it to the given filename, so it can be replayed using C<source>.
3217
3218Note that all C<^(save|source)>'s are commented out with a view to minimise recursion.
3219
3220=cut
3221
3222 # save source - write commands to a file for later use
ef18ae63
SF
3223 if (my ($new_fn) = $cmd =~ /\Asave\s*(.*)\z/) {
3224 my $filename = $new_fn || '.perl5dbrc'; # default?
3225 if ( open my $fh, '>', $filename ) {
e22ea7cc
RF
3226
3227 # chomp to remove extraneous newlines from source'd files
3228 chomp( my @truelist =
3229 map { m/^\s*(save|source)/ ? "#$_" : $_ }
3230 @truehist );
3231 print $fh join( "\n", @truelist );
69893cff 3232 print "commands saved in $file\n";
e22ea7cc
RF
3233 }
3234 else {
ef18ae63 3235 &warn("Can't save debugger commands in '$new_fn': $!\n");
69893cff
RGS
3236 }
3237 next CMD;
ef18ae63 3238 }
69893cff 3239
7fddc82f
RF
3240=head4 C<R> - restart
3241
ef18ae63 3242Restart the debugger session.
7fddc82f
RF
3243
3244=head4 C<rerun> - rerun the current session
3245
3246Return to any given position in the B<true>-history list
3247
3248=cut
3249
3250 # R - restart execution.
3251 # rerun - controlled restart execution.
ff41e38d
SF
3252 if (my ($cmd_cmd, $cmd_params) =
3253 $cmd =~ /\A((?:R)|(?:rerun\s*(.*)))\z/) {
3254 my @args = ($cmd_cmd eq 'R' ? restart() : rerun($cmd_params));
7fddc82f 3255
ca28b541
AP
3256 # Close all non-system fds for a clean restart. A more
3257 # correct method would be to close all fds that were not
3258 # open when the process started, but this seems to be
3259 # hard. See "debugger 'R'estart and open database
3260 # connections" on p5p.
3261
47d3bbda 3262 my $max_fd = 1024; # default if POSIX can't be loaded
ca28b541 3263 if (eval { require POSIX }) {
5332cc68 3264 eval { $max_fd = POSIX::sysconf(POSIX::_SC_OPEN_MAX()) };
ca28b541
AP
3265 }
3266
3267 if (defined $max_fd) {
3268 foreach ($^F+1 .. $max_fd-1) {
3269 next unless open FD_TO_CLOSE, "<&=$_";
3270 close(FD_TO_CLOSE);
3271 }
3272 }
3273
7fddc82f
RF
3274 # And run Perl again. We use exec() to keep the
3275 # PID stable (and that way $ini_pids is still valid).
3276 exec(@args) || print $OUT "exec failed: $!\n";
3277
3278 last CMD;
ff41e38d 3279 }
7fddc82f 3280
69893cff
RGS
3281=head4 C<|, ||> - pipe output through the pager.
3282
be9a9b1d 3283For C<|>, we save C<OUT> (the debugger's output filehandle) and C<STDOUT>
69893cff
RGS
3284(the program's standard output). For C<||>, we only save C<OUT>. We open a
3285pipe to the pager (restoring the output filehandles if this fails). If this
b570d64b 3286is the C<|> command, we also set up a C<SIGPIPE> handler which will simply
69893cff
RGS
3287set C<$signal>, sending us back into the debugger.
3288
3289We then trim off the pipe symbols and C<redo> the command loop at the
3290C<PIPE> label, causing us to evaluate the command in C<$cmd> without
3291reading another.
3292
3293=cut
3294
3295 # || - run command in the pager, with output to DB::OUT.
ff41e38d 3296 if ($cmd =~ m#\A\|\|?\s*[^|]#) {
e22ea7cc
RF
3297 if ( $pager =~ /^\|/ ) {
3298
69893cff 3299 # Default pager is into a pipe. Redirect I/O.
e22ea7cc
RF
3300 open( SAVEOUT, ">&STDOUT" )
3301 || &warn("Can't save STDOUT");
3302 open( STDOUT, ">&OUT" )
3303 || &warn("Can't redirect STDOUT");
69893cff 3304 } ## end if ($pager =~ /^\|/)
e22ea7cc
RF
3305 else {
3306
69893cff 3307 # Not into a pipe. STDOUT is safe.
e22ea7cc
RF
3308 open( SAVEOUT, ">&OUT" ) || &warn("Can't save DB::OUT");
3309 }
69893cff
RGS
3310
3311 # Fix up environment to record we have less if so.
e22ea7cc
RF
3312 fix_less();
3313
3314 unless ( $piped = open( OUT, $pager ) ) {
69893cff 3315
69893cff 3316 # Couldn't open pipe to pager.
1f874cb6 3317 &warn("Can't pipe output to '$pager'");
e22ea7cc
RF
3318 if ( $pager =~ /^\|/ ) {
3319
69893cff 3320 # Redirect I/O back again.
e22ea7cc
RF
3321 open( OUT, ">&STDOUT" ) # XXX: lost message
3322 || &warn("Can't restore DB::OUT");
3323 open( STDOUT, ">&SAVEOUT" )
3324 || &warn("Can't restore STDOUT");
3325 close(SAVEOUT);
69893cff 3326 } ## end if ($pager =~ /^\|/)
e22ea7cc
RF
3327 else {
3328
69893cff 3329 # Redirect I/O. STDOUT already safe.
e22ea7cc
RF
3330 open( OUT, ">&STDOUT" ) # XXX: lost message
3331 || &warn("Can't restore DB::OUT");
3332 }
3333 next CMD;
69893cff
RGS
3334 } ## end unless ($piped = open(OUT,...
3335
3336 # Set up broken-pipe handler if necessary.
e22ea7cc
RF
3337 $SIG{PIPE} = \&DB::catch
3338 if $pager =~ /^\|/
3339 && ( "" eq $SIG{PIPE} || "DEFAULT" eq $SIG{PIPE} );
69893cff 3340
70c9432b
SF
3341 OUT->autoflush(1);
3342 # Save current filehandle, and put it back.
e22ea7cc 3343 $selected = select(OUT);
69893cff 3344 # Don't put it back if pager was a pipe.
e22ea7cc 3345 select($selected), $selected = "" unless $cmd =~ /^\|\|/;
69893cff
RGS
3346
3347 # Trim off the pipe symbols and run the command now.
ff41e38d 3348 $cmd =~ s#\A\|+\s*##;
e22ea7cc 3349 redo PIPE;
ff41e38d 3350 }
69893cff
RGS
3351
3352=head3 END OF COMMAND PARSING
3353
ff41e38d
SF
3354Anything left in C<$cmd> at this point is a Perl expression that we want to
3355evaluate. We'll always evaluate in the user's context, and fully qualify
69893cff
RGS
3356any variables we might want to address in the C<DB> package.
3357
3358=cut
3359
3360 # t - turn trace on.
ff41e38d
SF
3361 if ($cmd =~ s#\At\s+(\d+)?#\$DB::trace |= 1;\n#) {
3362 my $trace_arg = $1;
3363 $trace_to_depth = $trace_arg ? $stack_depth||0 + $1 : 1E9;
3364 }
69893cff
RGS
3365
3366 # s - single-step. Remember the last command was 's'.
ff41e38d
SF
3367 if ($cmd =~ s/\As\s/\$DB::single = 1;\n/) {
3368 $laststep = 's';
3369 }
69893cff
RGS
3370
3371 # n - single-step, but not into subs. Remember last command
e22ea7cc 3372 # was 'n'.
ff41e38d
SF
3373 if ($cmd =~ s#\An\s#\$DB::single = 2;\n#) {
3374 $laststep = 'n';
3375 }
69893cff 3376
e22ea7cc 3377 } # PIPE:
69893cff 3378
e22ea7cc 3379 # Make sure the flag that says "the debugger's running" is
69893cff 3380 # still on, to make sure we get control again.
e22ea7cc 3381 $evalarg = "\$^D = \$^D | \$DB::db_stop;\n$cmd";
69893cff
RGS
3382
3383 # Run *our* eval that executes in the caller's context.
e22ea7cc 3384 &eval;
69893cff
RGS
3385
3386 # Turn off the one-time-dump stuff now.
e22ea7cc
RF
3387 if ($onetimeDump) {
3388 $onetimeDump = undef;
69893cff 3389 $onetimedumpDepth = undef;
e22ea7cc
RF
3390 }
3391 elsif ( $term_pid == $$ ) {
c7e68384
IZ
3392 eval { # May run under miniperl, when not available...
3393 STDOUT->flush();
3394 STDERR->flush();
3395 };
e22ea7cc 3396
69893cff 3397 # XXX If this is the master pid, print a newline.
e22ea7cc
RF
3398 print $OUT "\n";
3399 }
3400 } ## end while (($term || &setterm...
69893cff
RGS
3401
3402=head3 POST-COMMAND PROCESSING
3403
3404After each command, we check to see if the command output was piped anywhere.
3405If so, we go through the necessary code to unhook the pipe and go back to
3406our standard filehandles for input and output.
3407
3408=cut
3409
e22ea7cc 3410 continue { # CMD:
69893cff
RGS
3411
3412 # At the end of every command:
e22ea7cc
RF
3413 if ($piped) {
3414
69893cff 3415 # Unhook the pipe mechanism now.
e22ea7cc
RF
3416 if ( $pager =~ /^\|/ ) {
3417
69893cff 3418 # No error from the child.
e22ea7cc 3419 $? = 0;
69893cff 3420
e22ea7cc
RF
3421 # we cannot warn here: the handle is missing --tchrist
3422 close(OUT) || print SAVEOUT "\nCan't close DB::OUT\n";
69893cff 3423
e22ea7cc 3424 # most of the $? crud was coping with broken cshisms
69893cff 3425 # $? is explicitly set to 0, so this never runs.
e22ea7cc 3426 if ($?) {
1f874cb6 3427 print SAVEOUT "Pager '$pager' failed: ";
e22ea7cc
RF
3428 if ( $? == -1 ) {
3429 print SAVEOUT "shell returned -1\n";
3430 }
3431 elsif ( $? >> 8 ) {
3432 print SAVEOUT ( $? & 127 )
3433 ? " (SIG#" . ( $? & 127 ) . ")"
3434 : "", ( $? & 128 ) ? " -- core dumped" : "", "\n";
3435 }
3436 else {
3437 print SAVEOUT "status ", ( $? >> 8 ), "\n";
3438 }
69893cff
RGS
3439 } ## end if ($?)
3440
e22ea7cc 3441 # Reopen filehandle for our output (if we can) and
69893cff 3442 # restore STDOUT (if we can).
e22ea7cc
RF
3443 open( OUT, ">&STDOUT" ) || &warn("Can't restore DB::OUT");
3444 open( STDOUT, ">&SAVEOUT" )
3445 || &warn("Can't restore STDOUT");
69893cff
RGS
3446
3447 # Turn off pipe exception handler if necessary.
e22ea7cc 3448 $SIG{PIPE} = "DEFAULT" if $SIG{PIPE} eq \&DB::catch;
69893cff 3449
e22ea7cc
RF
3450 # Will stop ignoring SIGPIPE if done like nohup(1)
3451 # does SIGINT but Perl doesn't give us a choice.
69893cff 3452 } ## end if ($pager =~ /^\|/)
e22ea7cc
RF
3453 else {
3454
69893cff 3455 # Non-piped "pager". Just restore STDOUT.
e22ea7cc
RF
3456 open( OUT, ">&SAVEOUT" ) || &warn("Can't restore DB::OUT");
3457 }
69893cff
RGS
3458
3459 # Close filehandle pager was using, restore the normal one
3460 # if necessary,
3461 close(SAVEOUT);
e22ea7cc 3462 select($selected), $selected = "" unless $selected eq "";
69893cff
RGS
3463
3464 # No pipes now.
e22ea7cc 3465 $piped = "";
69893cff 3466 } ## end if ($piped)
e22ea7cc 3467 } # CMD:
69893cff
RGS
3468
3469=head3 COMMAND LOOP TERMINATION
3470
3471When commands have finished executing, we come here. If the user closed the
3472input filehandle, we turn on C<$fall_off_end> to emulate a C<q> command. We
3473evaluate any post-prompt items. We restore C<$@>, C<$!>, C<$^E>, C<$,>, C<$/>,
3474C<$\>, and C<$^W>, and return a null list as expected by the Perl interpreter.
3475The interpreter will then execute the next line and then return control to us
3476again.
3477
3478=cut
3479
3480 # No more commands? Quit.
1f874cb6 3481 $fall_off_end = 1 unless defined $cmd; # Emulate 'q' on EOF
69893cff
RGS
3482
3483 # Evaluate post-prompt commands.
e22ea7cc
RF
3484 foreach $evalarg (@$post) {
3485 &eval;
3486 }
3487 } # if ($single || $signal)
69893cff
RGS
3488
3489 # Put the user's globals back where you found them.
e22ea7cc 3490 ( $@, $!, $^E, $,, $/, $\, $^W ) = @saved;
69893cff
RGS
3491 ();
3492} ## end sub DB
3493
3494# The following code may be executed now:
3495# BEGIN {warn 4}
3496
3497=head2 sub
3498
b570d64b 3499C<sub> is called whenever a subroutine call happens in the program being
69893cff
RGS
3500debugged. The variable C<$DB::sub> contains the name of the subroutine
3501being called.
3502
3503The core function of this subroutine is to actually call the sub in the proper
3504context, capturing its output. This of course causes C<DB::DB> to get called
3505again, repeating until the subroutine ends and returns control to C<DB::sub>
3506again. Once control returns, C<DB::sub> figures out whether or not to dump the
3507return value, and returns its captured copy of the return value as its own
3508return value. The value then feeds back into the program being debugged as if
3509C<DB::sub> hadn't been there at all.
3510
3511C<sub> does all the work of printing the subroutine entry and exit messages
3512enabled by setting C<$frame>. It notes what sub the autoloader got called for,
b570d64b 3513and also prints the return value if needed (for the C<r> command and if
69893cff
RGS
3514the 16 bit is set in C<$frame>).
3515
3516It also tracks the subroutine call depth by saving the current setting of
3517C<$single> in the C<@stack> package global; if this exceeds the value in
3518C<$deep>, C<sub> automatically turns on printing of the current depth by
be9a9b1d 3519setting the C<4> bit in C<$single>. In any case, it keeps the current setting
69893cff
RGS
3520of stop/don't stop on entry to subs set as it currently is set.
3521
3522=head3 C<caller()> support
3523
3524If C<caller()> is called from the package C<DB>, it provides some
3525additional data, in the following order:
3526
3527=over 4
3528
3529=item * C<$package>
3530
3531The package name the sub was in
3532
3533=item * C<$filename>
3534
3535The filename it was defined in
3536
3537=item * C<$line>
3538
3539The line number it was defined on
3540
3541=item * C<$subroutine>
3542
be9a9b1d 3543The subroutine name; C<(eval)> if an C<eval>().
69893cff
RGS
3544
3545=item * C<$hasargs>
3546
35471 if it has arguments, 0 if not
3548
3549=item * C<$wantarray>