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e22ea7cc 1
b570d64b 2=head1 NAME
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be9a9b1d 4perl5db.pl - the perl debugger
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6=head1 SYNOPSIS
7
8 perl -d your_Perl_script
9
10=head1 DESCRIPTION
11
12C<perl5db.pl> is the perl debugger. It is loaded automatically by Perl when
13you invoke a script with C<perl -d>. This documentation tries to outline the
14structure and services provided by C<perl5db.pl>, and to describe how you
15can use them.
16
17=head1 GENERAL NOTES
18
19The debugger can look pretty forbidding to many Perl programmers. There are
20a number of reasons for this, many stemming out of the debugger's history.
21
22When the debugger was first written, Perl didn't have a lot of its nicer
23features - no references, no lexical variables, no closures, no object-oriented
24programming. So a lot of the things one would normally have done using such
b570d64b 25features was done using global variables, globs and the C<local()> operator
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26in creative ways.
27
28Some of these have survived into the current debugger; a few of the more
29interesting and still-useful idioms are noted in this section, along with notes
30on the comments themselves.
31
32=head2 Why not use more lexicals?
33
34Experienced Perl programmers will note that the debugger code tends to use
35mostly package globals rather than lexically-scoped variables. This is done
36to allow a significant amount of control of the debugger from outside the
b570d64b 37debugger itself.
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38
39Unfortunately, though the variables are accessible, they're not well
40documented, so it's generally been a decision that hasn't made a lot of
41difference to most users. Where appropriate, comments have been added to
42make variables more accessible and usable, with the understanding that these
be9a9b1d 43I<are> debugger internals, and are therefore subject to change. Future
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44development should probably attempt to replace the globals with a well-defined
45API, but for now, the variables are what we've got.
46
47=head2 Automated variable stacking via C<local()>
48
b570d64b 49As you may recall from reading C<perlfunc>, the C<local()> operator makes a
69893cff 50temporary copy of a variable in the current scope. When the scope ends, the
b570d64b 51old copy is restored. This is often used in the debugger to handle the
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52automatic stacking of variables during recursive calls:
53
54 sub foo {
55 local $some_global++;
56
57 # Do some stuff, then ...
58 return;
59 }
60
61What happens is that on entry to the subroutine, C<$some_global> is localized,
b570d64b 62then altered. When the subroutine returns, Perl automatically undoes the
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63localization, restoring the previous value. Voila, automatic stack management.
64
b570d64b 65The debugger uses this trick a I<lot>. Of particular note is C<DB::eval>,
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66which lets the debugger get control inside of C<eval>'ed code. The debugger
67localizes a saved copy of C<$@> inside the subroutine, which allows it to
68keep C<$@> safe until it C<DB::eval> returns, at which point the previous
b570d64b 69value of C<$@> is restored. This makes it simple (well, I<simpler>) to keep
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70track of C<$@> inside C<eval>s which C<eval> other C<eval's>.
71
72In any case, watch for this pattern. It occurs fairly often.
73
74=head2 The C<^> trick
75
b570d64b 76This is used to cleverly reverse the sense of a logical test depending on
69893cff 77the value of an auxiliary variable. For instance, the debugger's C<S>
b570d64b 78(search for subroutines by pattern) allows you to negate the pattern
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79like this:
80
81 # Find all non-'foo' subs:
b570d64b 82 S !/foo/
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83
84Boolean algebra states that the truth table for XOR looks like this:
85
86=over 4
87
b570d64b 88=item * 0 ^ 0 = 0
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89
90(! not present and no match) --> false, don't print
91
b570d64b 92=item * 0 ^ 1 = 1
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93
94(! not present and matches) --> true, print
95
b570d64b 96=item * 1 ^ 0 = 1
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97
98(! present and no match) --> true, print
99
b570d64b 100=item * 1 ^ 1 = 0
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101
102(! present and matches) --> false, don't print
103
104=back
105
106As you can see, the first pair applies when C<!> isn't supplied, and
be9a9b1d 107the second pair applies when it is. The XOR simply allows us to
b570d64b 108compact a more complicated if-then-elseif-else into a more elegant
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109(but perhaps overly clever) single test. After all, it needed this
110explanation...
111
112=head2 FLAGS, FLAGS, FLAGS
113
114There is a certain C programming legacy in the debugger. Some variables,
be9a9b1d 115such as C<$single>, C<$trace>, and C<$frame>, have I<magical> values composed
69893cff 116of 1, 2, 4, etc. (powers of 2) OR'ed together. This allows several pieces
b570d64b 117of state to be stored independently in a single scalar.
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118
119A test like
120
121 if ($scalar & 4) ...
122
b570d64b 123is checking to see if the appropriate bit is on. Since each bit can be
69893cff 124"addressed" independently in this way, C<$scalar> is acting sort of like
b570d64b 125an array of bits. Obviously, since the contents of C<$scalar> are just a
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126bit-pattern, we can save and restore it easily (it will just look like
127a number).
128
129The problem, is of course, that this tends to leave magic numbers scattered
b570d64b 130all over your program whenever a bit is set, cleared, or checked. So why do
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131it?
132
133=over 4
134
be9a9b1d 135=item *
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be9a9b1d 137First, doing an arithmetical or bitwise operation on a scalar is
69893cff 138just about the fastest thing you can do in Perl: C<use constant> actually
be9a9b1d 139creates a subroutine call, and array and hash lookups are much slower. Is
b570d64b 140this over-optimization at the expense of readability? Possibly, but the
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141debugger accesses these variables a I<lot>. Any rewrite of the code will
142probably have to benchmark alternate implementations and see which is the
b570d64b 143best balance of readability and speed, and then document how it actually
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144works.
145
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146=item *
147
b570d64b 148Second, it's very easy to serialize a scalar number. This is done in
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149the restart code; the debugger state variables are saved in C<%ENV> and then
150restored when the debugger is restarted. Having them be just numbers makes
b570d64b 151this trivial.
69893cff 152
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153=item *
154
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155Third, some of these variables are being shared with the Perl core
156smack in the middle of the interpreter's execution loop. It's much faster for
157a C program (like the interpreter) to check a bit in a scalar than to access
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158several different variables (or a Perl array).
159
160=back
161
162=head2 What are those C<XXX> comments for?
163
164Any comment containing C<XXX> means that the comment is either somewhat
b570d64b 165speculative - it's not exactly clear what a given variable or chunk of
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166code is doing, or that it is incomplete - the basics may be clear, but the
167subtleties are not completely documented.
168
169Send in a patch if you can clear up, fill out, or clarify an C<XXX>.
170
b570d64b 171=head1 DATA STRUCTURES MAINTAINED BY CORE
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172
173There are a number of special data structures provided to the debugger by
174the Perl interpreter.
175
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176The array C<@{$main::{'_<'.$filename}}> (aliased locally to C<@dbline>
177via glob assignment) contains the text from C<$filename>, with each
178element corresponding to a single line of C<$filename>. Additionally,
179breakable lines will be dualvars with the numeric component being the
180memory address of a COP node. Non-breakable lines are dualvar to 0.
69893cff 181
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182The hash C<%{'_<'.$filename}> (aliased locally to C<%dbline> via glob
183assignment) contains breakpoints and actions. The keys are line numbers;
184you can set individual values, but not the whole hash. The Perl interpreter
69893cff 185uses this hash to determine where breakpoints have been set. Any true value is
be9a9b1d 186considered to be a breakpoint; C<perl5db.pl> uses C<$break_condition\0$action>.
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187Values are magical in numeric context: 1 if the line is breakable, 0 if not.
188
ef18ae63 189The scalar C<${"_<$filename"}> simply contains the string C<<< _<$filename> >>>.
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190This is also the case for evaluated strings that contain subroutines, or
191which are currently being executed. The $filename for C<eval>ed strings looks
d24ca0c5 192like C<(eval 34).
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193
194=head1 DEBUGGER STARTUP
195
196When C<perl5db.pl> starts, it reads an rcfile (C<perl5db.ini> for
197non-interactive sessions, C<.perldb> for interactive ones) that can set a number
198of options. In addition, this file may define a subroutine C<&afterinit>
b570d64b 199that will be executed (in the debugger's context) after the debugger has
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200initialized itself.
201
b570d64b 202Next, it checks the C<PERLDB_OPTS> environment variable and treats its
be9a9b1d 203contents as the argument of a C<o> command in the debugger.
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204
205=head2 STARTUP-ONLY OPTIONS
206
207The following options can only be specified at startup.
208To set them in your rcfile, add a call to
209C<&parse_options("optionName=new_value")>.
210
211=over 4
212
b570d64b 213=item * TTY
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214
215the TTY to use for debugging i/o.
216
b570d64b 217=item * noTTY
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218
219if set, goes in NonStop mode. On interrupt, if TTY is not set,
b0e77abc 220uses the value of noTTY or F<$HOME/.perldbtty$$> to find TTY using
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221Term::Rendezvous. Current variant is to have the name of TTY in this
222file.
223
b570d64b 224=item * ReadLine
69893cff 225
5561b870 226if false, a dummy ReadLine is used, so you can debug
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227ReadLine applications.
228
b570d64b 229=item * NonStop
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230
231if true, no i/o is performed until interrupt.
232
b570d64b 233=item * LineInfo
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234
235file or pipe to print line number info to. If it is a
236pipe, a short "emacs like" message is used.
237
b570d64b 238=item * RemotePort
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239
240host:port to connect to on remote host for remote debugging.
241
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242=item * HistFile
243
244file to store session history to. There is no default and so no
245history file is written unless this variable is explicitly set.
246
247=item * HistSize
248
249number of commands to store to the file specified in C<HistFile>.
250Default is 100.
251
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252=back
253
254=head3 SAMPLE RCFILE
255
256 &parse_options("NonStop=1 LineInfo=db.out");
257 sub afterinit { $trace = 1; }
258
259The script will run without human intervention, putting trace
260information into C<db.out>. (If you interrupt it, you had better
be9a9b1d 261reset C<LineInfo> to something I<interactive>!)
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262
263=head1 INTERNALS DESCRIPTION
264
265=head2 DEBUGGER INTERFACE VARIABLES
266
267Perl supplies the values for C<%sub>. It effectively inserts
be9a9b1d 268a C<&DB::DB();> in front of each place that can have a
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269breakpoint. At each subroutine call, it calls C<&DB::sub> with
270C<$DB::sub> set to the called subroutine. It also inserts a C<BEGIN
271{require 'perl5db.pl'}> before the first line.
272
273After each C<require>d file is compiled, but before it is executed, a
274call to C<&DB::postponed($main::{'_<'.$filename})> is done. C<$filename>
275is the expanded name of the C<require>d file (as found via C<%INC>).
276
277=head3 IMPORTANT INTERNAL VARIABLES
278
279=head4 C<$CreateTTY>
280
281Used to control when the debugger will attempt to acquire another TTY to be
b570d64b 282used for input.
69893cff 283
b570d64b 284=over
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285
286=item * 1 - on C<fork()>
287
288=item * 2 - debugger is started inside debugger
289
290=item * 4 - on startup
291
292=back
293
294=head4 C<$doret>
295
296The value -2 indicates that no return value should be printed.
297Any other positive value causes C<DB::sub> to print return values.
298
299=head4 C<$evalarg>
300
301The item to be eval'ed by C<DB::eval>. Used to prevent messing with the current
302contents of C<@_> when C<DB::eval> is called.
303
304=head4 C<$frame>
305
306Determines what messages (if any) will get printed when a subroutine (or eval)
b570d64b 307is entered or exited.
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308
309=over 4
310
311=item * 0 - No enter/exit messages
312
be9a9b1d 313=item * 1 - Print I<entering> messages on subroutine entry
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314
315=item * 2 - Adds exit messages on subroutine exit. If no other flag is on, acts like 1+2.
316
be9a9b1d 317=item * 4 - Extended messages: C<< <in|out> I<context>=I<fully-qualified sub name> from I<file>:I<line> >>. If no other flag is on, acts like 1+4.
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318
319=item * 8 - Adds parameter information to messages, and overloaded stringify and tied FETCH is enabled on the printed arguments. Ignored if C<4> is not on.
320
321=item * 16 - Adds C<I<context> return from I<subname>: I<value>> messages on subroutine/eval exit. Ignored if C<4> is is not on.
322
323=back
324
be9a9b1d 325To get everything, use C<$frame=30> (or C<o f=30> as a debugger command).
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326The debugger internally juggles the value of C<$frame> during execution to
327protect external modules that the debugger uses from getting traced.
328
329=head4 C<$level>
330
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331Tracks current debugger nesting level. Used to figure out how many
332C<E<lt>E<gt>> pairs to surround the line number with when the debugger
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333outputs a prompt. Also used to help determine if the program has finished
334during command parsing.
335
336=head4 C<$onetimeDump>
337
338Controls what (if anything) C<DB::eval()> will print after evaluating an
339expression.
340
341=over 4
342
343=item * C<undef> - don't print anything
344
345=item * C<dump> - use C<dumpvar.pl> to display the value returned
346
347=item * C<methods> - print the methods callable on the first item returned
348
349=back
350
351=head4 C<$onetimeDumpDepth>
352
be9a9b1d 353Controls how far down C<dumpvar.pl> will go before printing C<...> while
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354dumping a structure. Numeric. If C<undef>, print all levels.
355
356=head4 C<$signal>
357
358Used to track whether or not an C<INT> signal has been detected. C<DB::DB()>,
359which is called before every statement, checks this and puts the user into
360command mode if it finds C<$signal> set to a true value.
361
362=head4 C<$single>
363
364Controls behavior during single-stepping. Stacked in C<@stack> on entry to
365each subroutine; popped again at the end of each subroutine.
366
b570d64b 367=over 4
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368
369=item * 0 - run continuously.
370
be9a9b1d 371=item * 1 - single-step, go into subs. The C<s> command.
69893cff 372
be9a9b1d 373=item * 2 - single-step, don't go into subs. The C<n> command.
69893cff 374
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375=item * 4 - print current sub depth (turned on to force this when C<too much
376recursion> occurs.
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377
378=back
379
380=head4 C<$trace>
381
b570d64b 382Controls the output of trace information.
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383
384=over 4
385
386=item * 1 - The C<t> command was entered to turn on tracing (every line executed is printed)
387
388=item * 2 - watch expressions are active
389
390=item * 4 - user defined a C<watchfunction()> in C<afterinit()>
391
392=back
393
394=head4 C<$slave_editor>
395
3961 if C<LINEINFO> was directed to a pipe; 0 otherwise.
397
398=head4 C<@cmdfhs>
399
400Stack of filehandles that C<DB::readline()> will read commands from.
401Manipulated by the debugger's C<source> command and C<DB::readline()> itself.
402
403=head4 C<@dbline>
404
b570d64b 405Local alias to the magical line array, C<@{$main::{'_<'.$filename}}> ,
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406supplied by the Perl interpreter to the debugger. Contains the source.
407
408=head4 C<@old_watch>
409
410Previous values of watch expressions. First set when the expression is
411entered; reset whenever the watch expression changes.
412
413=head4 C<@saved>
414
415Saves important globals (C<$@>, C<$!>, C<$^E>, C<$,>, C<$/>, C<$\>, C<$^W>)
416so that the debugger can substitute safe values while it's running, and
417restore them when it returns control.
418
419=head4 C<@stack>
420
421Saves the current value of C<$single> on entry to a subroutine.
422Manipulated by the C<c> command to turn off tracing in all subs above the
423current one.
424
425=head4 C<@to_watch>
426
427The 'watch' expressions: to be evaluated before each line is executed.
428
429=head4 C<@typeahead>
430
431The typeahead buffer, used by C<DB::readline>.
432
433=head4 C<%alias>
434
435Command aliases. Stored as character strings to be substituted for a command
436entered.
437
438=head4 C<%break_on_load>
439
440Keys are file names, values are 1 (break when this file is loaded) or undef
441(don't break when it is loaded).
442
443=head4 C<%dbline>
444
be9a9b1d 445Keys are line numbers, values are C<condition\0action>. If used in numeric
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446context, values are 0 if not breakable, 1 if breakable, no matter what is
447in the actual hash entry.
448
449=head4 C<%had_breakpoints>
450
451Keys are file names; values are bitfields:
452
b570d64b 453=over 4
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454
455=item * 1 - file has a breakpoint in it.
456
457=item * 2 - file has an action in it.
458
459=back
460
461A zero or undefined value means this file has neither.
462
463=head4 C<%option>
464
465Stores the debugger options. These are character string values.
466
467=head4 C<%postponed>
468
469Saves breakpoints for code that hasn't been compiled yet.
470Keys are subroutine names, values are:
471
472=over 4
473
be9a9b1d 474=item * C<compile> - break when this sub is compiled
69893cff 475
be9a9b1d 476=item * C<< break +0 if <condition> >> - break (conditionally) at the start of this routine. The condition will be '1' if no condition was specified.
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477
478=back
479
480=head4 C<%postponed_file>
481
482This hash keeps track of breakpoints that need to be set for files that have
483not yet been compiled. Keys are filenames; values are references to hashes.
484Each of these hashes is keyed by line number, and its values are breakpoint
be9a9b1d 485definitions (C<condition\0action>).
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486
487=head1 DEBUGGER INITIALIZATION
488
489The debugger's initialization actually jumps all over the place inside this
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490package. This is because there are several BEGIN blocks (which of course
491execute immediately) spread through the code. Why is that?
69893cff 492
b570d64b 493The debugger needs to be able to change some things and set some things up
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494before the debugger code is compiled; most notably, the C<$deep> variable that
495C<DB::sub> uses to tell when a program has recursed deeply. In addition, the
496debugger has to turn off warnings while the debugger code is compiled, but then
497restore them to their original setting before the program being debugged begins
498executing.
499
500The first C<BEGIN> block simply turns off warnings by saving the current
501setting of C<$^W> and then setting it to zero. The second one initializes
502the debugger variables that are needed before the debugger begins executing.
b570d64b 503The third one puts C<$^X> back to its former value.
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504
505We'll detail the second C<BEGIN> block later; just remember that if you need
506to initialize something before the debugger starts really executing, that's
507where it has to go.
508
509=cut
510
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511package DB;
512
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513use strict;
514
c7e68384 515BEGIN {eval 'use IO::Handle'}; # Needed for flush only? breaks under miniperl
9eba6a4e 516
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517BEGIN {
518 require feature;
519 $^V =~ /^v(\d+\.\d+)/;
520 feature->import(":$1");
521}
522
54d04a52 523# Debugger for Perl 5.00x; perl5db.pl patch level:
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524use vars qw($VERSION $header);
525
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
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599
600=back
601
602=head3 The problem of lexicals
603
604The context of C<DB::eval()> presents us with some problems. Obviously,
605we want to be 'sandboxed' away from the debugger's internals when we do
606the eval, but we need some way to control how punctuation variables and
b570d64b 607debugger globals are used.
69893cff
RGS
608
609We can't use local, because the code inside C<DB::eval> can see localized
610variables; and we can't use C<my> either for the same reason. The code
611in this routine compromises and uses C<my>.
612
613After this routine is over, we don't have user code executing in the debugger's
614context, so we can use C<my> freely.
615
616=cut
617
618############################################## Begin lexical danger zone
619
620# 'my' variables used here could leak into (that is, be visible in)
621# the context that the code being evaluated is executing in. This means that
622# the code could modify the debugger's variables.
623#
624# Fiddling with the debugger's context could be Bad. We insulate things as
625# much as we can.
626
6b24a4b7
SF
627use vars qw(
628 @args
629 %break_on_load
630 @cmdfhs
631 $CommandSet
632 $CreateTTY
633 $DBGR
634 @dbline
635 $dbline
636 %dbline
637 $dieLevel
638 $evalarg
639 $filename
640 $frame
641 $hist
642 $histfile
643 $histsize
644 $ImmediateStop
645 $IN
646 $inhibit_exit
647 @ini_INC
648 $ini_warn
649 $line
650 $maxtrace
651 $od
652 $onetimeDump
653 $onetimedumpDepth
654 %option
655 @options
656 $osingle
657 $otrace
658 $OUT
659 $packname
660 $pager
661 $post
662 %postponed
663 $prc
664 $pre
665 $pretype
666 $psh
667 @RememberOnROptions
668 $remoteport
669 @res
670 $rl
671 @saved
672 $signal
673 $signalLevel
674 $single
675 $start
676 $sub
677 %sub
678 $subname
679 $term
680 $trace
681 $usercontext
682 $warnLevel
683 $window
684);
685
686# Used to save @ARGV and extract any debugger-related flags.
687use vars qw(@ARGS);
688
689# Used to prevent multiple entries to diesignal()
690# (if for instance diesignal() itself dies)
691use vars qw($panic);
692
693# Used to prevent the debugger from running nonstop
694# after a restart
695use vars qw($second_time);
696
697sub _calc_usercontext {
698 my ($package) = @_;
699
700 # Cancel strict completely for the evaluated code, so the code
701 # the user evaluates won't be affected by it. (Shlomi Fish)
702 return 'no strict; ($@, $!, $^E, $,, $/, $\, $^W) = @saved;'
703 . "package $package;"; # this won't let them modify, alas
704}
705
c1051fcf 706sub eval {
69893cff 707
c1051fcf 708 # 'my' would make it visible from user code
e22ea7cc 709 # but so does local! --tchrist
69893cff 710 # Remember: this localizes @DB::res, not @main::res.
c1051fcf
IZ
711 local @res;
712 {
e22ea7cc
RF
713
714 # Try to keep the user code from messing with us. Save these so that
715 # even if the eval'ed code changes them, we can put them back again.
716 # Needed because the user could refer directly to the debugger's
69893cff
RGS
717 # package globals (and any 'my' variables in this containing scope)
718 # inside the eval(), and we want to try to stay safe.
e22ea7cc 719 local $otrace = $trace;
69893cff
RGS
720 local $osingle = $single;
721 local $od = $^D;
722
723 # Untaint the incoming eval() argument.
724 { ($evalarg) = $evalarg =~ /(.*)/s; }
725
e22ea7cc 726 # $usercontext built in DB::DB near the comment
69893cff
RGS
727 # "set up the context for DB::eval ..."
728 # Evaluate and save any results.
e22ea7cc 729 @res = eval "$usercontext $evalarg;\n"; # '\n' for nice recursive debug
69893cff
RGS
730
731 # Restore those old values.
732 $trace = $otrace;
733 $single = $osingle;
734 $^D = $od;
c1051fcf 735 }
69893cff
RGS
736
737 # Save the current value of $@, and preserve it in the debugger's copy
738 # of the saved precious globals.
c1051fcf 739 my $at = $@;
69893cff
RGS
740
741 # Since we're only saving $@, we only have to localize the array element
742 # that it will be stored in.
e22ea7cc 743 local $saved[0]; # Preserve the old value of $@
c1051fcf 744 eval { &DB::save };
69893cff
RGS
745
746 # Now see whether we need to report an error back to the user.
c1051fcf 747 if ($at) {
69893cff
RGS
748 local $\ = '';
749 print $OUT $at;
750 }
751
752 # Display as required by the caller. $onetimeDump and $onetimedumpDepth
753 # are package globals.
754 elsif ($onetimeDump) {
e22ea7cc
RF
755 if ( $onetimeDump eq 'dump' ) {
756 local $option{dumpDepth} = $onetimedumpDepth
757 if defined $onetimedumpDepth;
758 dumpit( $OUT, \@res );
759 }
760 elsif ( $onetimeDump eq 'methods' ) {
761 methods( $res[0] );
762 }
69893cff 763 } ## end elsif ($onetimeDump)
c1051fcf 764 @res;
69893cff
RGS
765} ## end sub eval
766
767############################################## End lexical danger zone
c1051fcf 768
e22ea7cc
RF
769# After this point it is safe to introduce lexicals.
770# The code being debugged will be executing in its own context, and
69893cff 771# can't see the inside of the debugger.
d338d6fe 772#
e22ea7cc 773# However, one should not overdo it: leave as much control from outside as
69893cff
RGS
774# possible. If you make something a lexical, it's not going to be addressable
775# from outside the debugger even if you know its name.
776
d338d6fe
PP
777# This file is automatically included if you do perl -d.
778# It's probably not useful to include this yourself.
779#
e22ea7cc 780# Before venturing further into these twisty passages, it is
2f7e9187
MS
781# wise to read the perldebguts man page or risk the ire of dragons.
782#
69893cff
RGS
783# (It should be noted that perldebguts will tell you a lot about
784# the underlying mechanics of how the debugger interfaces into the
785# Perl interpreter, but not a lot about the debugger itself. The new
786# comments in this code try to address this problem.)
787
d338d6fe 788# Note that no subroutine call is possible until &DB::sub is defined
36477c24 789# (for subroutines defined outside of the package DB). In fact the same is
d338d6fe 790# true if $deep is not defined.
055fd3a9
GS
791
792# Enhanced by ilya@math.ohio-state.edu (Ilya Zakharevich)
055fd3a9
GS
793
794# modified Perl debugger, to be run from Emacs in perldb-mode
795# Ray Lischner (uunet!mntgfx!lisch) as of 5 Nov 1990
796# Johan Vromans -- upgrade to 4.0 pl 10
797# Ilya Zakharevich -- patches after 5.001 (and some before ;-)
6fae1ad7 798########################################################################
d338d6fe 799
69893cff
RGS
800=head1 DEBUGGER INITIALIZATION
801
802The debugger starts up in phases.
803
804=head2 BASIC SETUP
805
806First, it initializes the environment it wants to run in: turning off
807warnings during its own compilation, defining variables which it will need
808to avoid warnings later, setting itself up to not exit when the program
809terminates, and defaulting to printing return values for the C<r> command.
810
811=cut
812
eda6e075 813# Needed for the statement after exec():
69893cff
RGS
814#
815# This BEGIN block is simply used to switch off warnings during debugger
98dc9551 816# compilation. Probably it would be better practice to fix the warnings,
69893cff 817# but this is how it's done at the moment.
eda6e075 818
e22ea7cc
RF
819BEGIN {
820 $ini_warn = $^W;
821 $^W = 0;
822} # Switch compilation warnings off until another BEGIN.
d12a4851 823
69893cff
RGS
824local ($^W) = 0; # Switch run-time warnings off during init.
825
2cbb2ee1
RGS
826=head2 THREADS SUPPORT
827
828If we are running under a threaded Perl, we require threads and threads::shared
829if the environment variable C<PERL5DB_THREADED> is set, to enable proper
830threaded debugger control. C<-dt> can also be used to set this.
831
832Each new thread will be announced and the debugger prompt will always inform
833you of each new thread created. It will also indicate the thread id in which
834we are currently running within the prompt like this:
835
836 [tid] DB<$i>
837
838Where C<[tid]> is an integer thread id and C<$i> is the familiar debugger
839command prompt. The prompt will show: C<[0]> when running under threads, but
840not actually in a thread. C<[tid]> is consistent with C<gdb> usage.
841
842While running under threads, when you set or delete a breakpoint (etc.), this
b570d64b 843will apply to all threads, not just the currently running one. When you are
2cbb2ee1
RGS
844in a currently executing thread, you will stay there until it completes. With
845the current implementation it is not currently possible to hop from one thread
846to another.
847
848The C<e> and C<E> commands are currently fairly minimal - see C<h e> and C<h E>.
849
850Note that threading support was built into the debugger as of Perl version
851C<5.8.6> and debugger version C<1.2.8>.
852
853=cut
854
855BEGIN {
856 # ensure we can share our non-threaded variables or no-op
857 if ($ENV{PERL5DB_THREADED}) {
858 require threads;
859 require threads::shared;
860 import threads::shared qw(share);
861 $DBGR;
862 share(\$DBGR);
863 lock($DBGR);
864 print "Threads support enabled\n";
865 } else {
866 *lock = sub(*) {};
867 *share = sub(*) {};
868 }
869}
870
2218c045
SF
871# These variables control the execution of 'dumpvar.pl'.
872{
873 package dumpvar;
874 use vars qw(
875 $hashDepth
876 $arrayDepth
877 $dumpDBFiles
878 $dumpPackages
879 $quoteHighBit
880 $printUndef
881 $globPrint
882 $usageOnly
883 );
884}
69893cff 885
2218c045
SF
886# used to control die() reporting in diesignal()
887{
888 package Carp;
889 use vars qw($CarpLevel);
890}
d338d6fe 891
422c59bf 892# without threads, $filename is not defined until DB::DB is called
2cbb2ee1 893foreach my $k (keys (%INC)) {
fb4d8a6c 894 share(\$main::{'_<'.$filename}) if defined $filename;
2cbb2ee1
RGS
895};
896
54d04a52 897# Command-line + PERLLIB:
69893cff 898# Save the contents of @INC before they are modified elsewhere.
54d04a52
IZ
899@ini_INC = @INC;
900
69893cff
RGS
901# This was an attempt to clear out the previous values of various
902# trapped errors. Apparently it didn't help. XXX More info needed!
d338d6fe
PP
903# $prevwarn = $prevdie = $prevbus = $prevsegv = ''; # Does not help?!
904
69893cff
RGS
905# We set these variables to safe values. We don't want to blindly turn
906# off warnings, because other packages may still want them.
e22ea7cc
RF
907$trace = $signal = $single = 0; # Uninitialized warning suppression
908 # (local $^W cannot help - other packages!).
69893cff
RGS
909
910# Default to not exiting when program finishes; print the return
911# value when the 'r' command is used to return from a subroutine.
55497cff 912$inhibit_exit = $option{PrintRet} = 1;
d338d6fe 913
6b24a4b7
SF
914use vars qw($trace_to_depth);
915
5e2b42dd
SF
916# Default to 1E9 so it won't be limited to a certain recursion depth.
917$trace_to_depth = 1E9;
bdba49ad 918
69893cff
RGS
919=head1 OPTION PROCESSING
920
b570d64b
SF
921The debugger's options are actually spread out over the debugger itself and
922C<dumpvar.pl>; some of these are variables to be set, while others are
69893cff
RGS
923subs to be called with a value. To try to make this a little easier to
924manage, the debugger uses a few data structures to define what options
925are legal and how they are to be processed.
926
927First, the C<@options> array defines the I<names> of all the options that
928are to be accepted.
929
930=cut
931
932@options = qw(
5561b870 933 CommandSet HistFile HistSize
e22ea7cc
RF
934 hashDepth arrayDepth dumpDepth
935 DumpDBFiles DumpPackages DumpReused
936 compactDump veryCompact quote
937 HighBit undefPrint globPrint
938 PrintRet UsageOnly frame
939 AutoTrace TTY noTTY
940 ReadLine NonStop LineInfo
941 maxTraceLen recallCommand ShellBang
942 pager tkRunning ornaments
943 signalLevel warnLevel dieLevel
944 inhibit_exit ImmediateStop bareStringify
945 CreateTTY RemotePort windowSize
584420f0 946 DollarCaretP
e22ea7cc 947);
d12a4851 948
584420f0 949@RememberOnROptions = qw(DollarCaretP);
d12a4851 950
69893cff
RGS
951=pod
952
953Second, C<optionVars> lists the variables that each option uses to save its
954state.
955
956=cut
957
6b24a4b7
SF
958use vars qw(%optionVars);
959
69893cff 960%optionVars = (
e22ea7cc
RF
961 hashDepth => \$dumpvar::hashDepth,
962 arrayDepth => \$dumpvar::arrayDepth,
963 CommandSet => \$CommandSet,
964 DumpDBFiles => \$dumpvar::dumpDBFiles,
965 DumpPackages => \$dumpvar::dumpPackages,
966 DumpReused => \$dumpvar::dumpReused,
967 HighBit => \$dumpvar::quoteHighBit,
968 undefPrint => \$dumpvar::printUndef,
969 globPrint => \$dumpvar::globPrint,
970 UsageOnly => \$dumpvar::usageOnly,
971 CreateTTY => \$CreateTTY,
972 bareStringify => \$dumpvar::bareStringify,
973 frame => \$frame,
974 AutoTrace => \$trace,
975 inhibit_exit => \$inhibit_exit,
976 maxTraceLen => \$maxtrace,
977 ImmediateStop => \$ImmediateStop,
978 RemotePort => \$remoteport,
979 windowSize => \$window,
5561b870
AK
980 HistFile => \$histfile,
981 HistSize => \$histsize,
69893cff
RGS
982);
983
984=pod
985
986Third, C<%optionAction> defines the subroutine to be called to process each
987option.
988
b570d64b 989=cut
69893cff 990
6b24a4b7
SF
991use vars qw(%optionAction);
992
69893cff
RGS
993%optionAction = (
994 compactDump => \&dumpvar::compactDump,
995 veryCompact => \&dumpvar::veryCompact,
996 quote => \&dumpvar::quote,
997 TTY => \&TTY,
998 noTTY => \&noTTY,
999 ReadLine => \&ReadLine,
1000 NonStop => \&NonStop,
1001 LineInfo => \&LineInfo,
1002 recallCommand => \&recallCommand,
1003 ShellBang => \&shellBang,
1004 pager => \&pager,
1005 signalLevel => \&signalLevel,
1006 warnLevel => \&warnLevel,
1007 dieLevel => \&dieLevel,
1008 tkRunning => \&tkRunning,
1009 ornaments => \&ornaments,
1010 RemotePort => \&RemotePort,
1011 DollarCaretP => \&DollarCaretP,
d12a4851
JH
1012);
1013
69893cff
RGS
1014=pod
1015
1016Last, the C<%optionRequire> notes modules that must be C<require>d if an
1017option is used.
1018
1019=cut
d338d6fe 1020
69893cff
RGS
1021# Note that this list is not complete: several options not listed here
1022# actually require that dumpvar.pl be loaded for them to work, but are
1023# not in the table. A subsequent patch will correct this problem; for
1024# the moment, we're just recommenting, and we are NOT going to change
1025# function.
6b24a4b7
SF
1026use vars qw(%optionRequire);
1027
eda6e075 1028%optionRequire = (
69893cff
RGS
1029 compactDump => 'dumpvar.pl',
1030 veryCompact => 'dumpvar.pl',
1031 quote => 'dumpvar.pl',
e22ea7cc 1032);
69893cff
RGS
1033
1034=pod
1035
1036There are a number of initialization-related variables which can be set
1037by putting code to set them in a BEGIN block in the C<PERL5DB> environment
1038variable. These are:
1039
1040=over 4
1041
1042=item C<$rl> - readline control XXX needs more explanation
1043
1044=item C<$warnLevel> - whether or not debugger takes over warning handling
1045
1046=item C<$dieLevel> - whether or not debugger takes over die handling
1047
1048=item C<$signalLevel> - whether or not debugger takes over signal handling
1049
1050=item C<$pre> - preprompt actions (array reference)
1051
1052=item C<$post> - postprompt actions (array reference)
1053
1054=item C<$pretype>
1055
1056=item C<$CreateTTY> - whether or not to create a new TTY for this debugger
1057
1058=item C<$CommandSet> - which command set to use (defaults to new, documented set)
1059
1060=back
1061
1062=cut
d338d6fe
PP
1063
1064# These guys may be defined in $ENV{PERL5DB} :
69893cff
RGS
1065$rl = 1 unless defined $rl;
1066$warnLevel = 1 unless defined $warnLevel;
1067$dieLevel = 1 unless defined $dieLevel;
1068$signalLevel = 1 unless defined $signalLevel;
1069$pre = [] unless defined $pre;
1070$post = [] unless defined $post;
1071$pretype = [] unless defined $pretype;
1072$CreateTTY = 3 unless defined $CreateTTY;
1073$CommandSet = '580' unless defined $CommandSet;
1074
2cbb2ee1
RGS
1075share($rl);
1076share($warnLevel);
1077share($dieLevel);
1078share($signalLevel);
1079share($pre);
1080share($post);
1081share($pretype);
1082share($rl);
1083share($CreateTTY);
1084share($CommandSet);
1085
69893cff
RGS
1086=pod
1087
1088The default C<die>, C<warn>, and C<signal> handlers are set up.
1089
1090=cut
055fd3a9 1091
d338d6fe
PP
1092warnLevel($warnLevel);
1093dieLevel($dieLevel);
1094signalLevel($signalLevel);
055fd3a9 1095
69893cff
RGS
1096=pod
1097
1098The pager to be used is needed next. We try to get it from the
5561b870 1099environment first. If it's not defined there, we try to find it in
69893cff
RGS
1100the Perl C<Config.pm>. If it's not there, we default to C<more>. We
1101then call the C<pager()> function to save the pager name.
1102
1103=cut
1104
1105# This routine makes sure $pager is set up so that '|' can use it.
4865a36d 1106pager(
e22ea7cc 1107
69893cff 1108 # If PAGER is defined in the environment, use it.
e22ea7cc
RF
1109 defined $ENV{PAGER}
1110 ? $ENV{PAGER}
69893cff
RGS
1111
1112 # If not, see if Config.pm defines it.
e22ea7cc
RF
1113 : eval { require Config }
1114 && defined $Config::Config{pager}
1115 ? $Config::Config{pager}
69893cff
RGS
1116
1117 # If not, fall back to 'more'.
e22ea7cc
RF
1118 : 'more'
1119 )
1120 unless defined $pager;
69893cff
RGS
1121
1122=pod
1123
1124We set up the command to be used to access the man pages, the command
be9a9b1d
AT
1125recall character (C<!> unless otherwise defined) and the shell escape
1126character (C<!> unless otherwise defined). Yes, these do conflict, and
69893cff
RGS
1127neither works in the debugger at the moment.
1128
1129=cut
1130
055fd3a9 1131setman();
69893cff
RGS
1132
1133# Set up defaults for command recall and shell escape (note:
1134# these currently don't work in linemode debugging).
2218c045
SF
1135recallCommand("!") unless defined $prc;
1136shellBang("!") unless defined $psh;
69893cff
RGS
1137
1138=pod
1139
1140We then set up the gigantic string containing the debugger help.
1141We also set the limit on the number of arguments we'll display during a
1142trace.
1143
1144=cut
1145
04e43a21 1146sethelp();
69893cff
RGS
1147
1148# If we didn't get a default for the length of eval/stack trace args,
1149# set it here.
1d06cb2d 1150$maxtrace = 400 unless defined $maxtrace;
69893cff
RGS
1151
1152=head2 SETTING UP THE DEBUGGER GREETING
1153
be9a9b1d 1154The debugger I<greeting> helps to inform the user how many debuggers are
69893cff
RGS
1155running, and whether the current debugger is the primary or a child.
1156
1157If we are the primary, we just hang onto our pid so we'll have it when
1158or if we start a child debugger. If we are a child, we'll set things up
1159so we'll have a unique greeting and so the parent will give us our own
1160TTY later.
1161
1162We save the current contents of the C<PERLDB_PIDS> environment variable
1163because we mess around with it. We'll also need to hang onto it because
1164we'll need it if we restart.
1165
1166Child debuggers make a label out of the current PID structure recorded in
1167PERLDB_PIDS plus the new PID. They also mark themselves as not having a TTY
1168yet so the parent will give them one later via C<resetterm()>.
1169
1170=cut
1171
e22ea7cc 1172# Save the current contents of the environment; we're about to
69893cff 1173# much with it. We'll need this if we have to restart.
6b24a4b7 1174use vars qw($ini_pids);
f1583d8f 1175$ini_pids = $ENV{PERLDB_PIDS};
69893cff 1176
6b24a4b7
SF
1177use vars qw ($pids $term_pid);
1178
e22ea7cc
RF
1179if ( defined $ENV{PERLDB_PIDS} ) {
1180
69893cff 1181 # We're a child. Make us a label out of the current PID structure
e22ea7cc 1182 # recorded in PERLDB_PIDS plus our (new) PID. Mark us as not having
69893cff 1183 # a term yet so the parent will give us one later via resetterm().
55f4245e
JM
1184
1185 my $env_pids = $ENV{PERLDB_PIDS};
1186 $pids = "[$env_pids]";
1187
1188 # Unless we are on OpenVMS, all programs under the DCL shell run under
1189 # the same PID.
1190
1191 if (($^O eq 'VMS') && ($env_pids =~ /\b$$\b/)) {
1192 $term_pid = $$;
1193 }
1194 else {
1195 $ENV{PERLDB_PIDS} .= "->$$";
1196 $term_pid = -1;
1197 }
1198
69893cff
RGS
1199} ## end if (defined $ENV{PERLDB_PIDS...
1200else {
e22ea7cc
RF
1201
1202 # We're the parent PID. Initialize PERLDB_PID in case we end up with a
69893cff
RGS
1203 # child debugger, and mark us as the parent, so we'll know to set up
1204 # more TTY's is we have to.
1205 $ENV{PERLDB_PIDS} = "$$";
619a0444 1206 $pids = "[pid=$$]";
e22ea7cc 1207 $term_pid = $$;
f1583d8f 1208}
69893cff 1209
6b24a4b7 1210use vars qw($pidprompt);
f1583d8f 1211$pidprompt = '';
69893cff
RGS
1212
1213# Sets up $emacs as a synonym for $slave_editor.
6b24a4b7 1214use vars qw($slave_editor);
69893cff
RGS
1215*emacs = $slave_editor if $slave_editor; # May be used in afterinit()...
1216
1217=head2 READING THE RC FILE
1218
b570d64b 1219The debugger will read a file of initialization options if supplied. If
69893cff
RGS
1220running interactively, this is C<.perldb>; if not, it's C<perldb.ini>.
1221
b570d64b 1222=cut
69893cff
RGS
1223
1224# As noted, this test really doesn't check accurately that the debugger
1225# is running at a terminal or not.
d338d6fe 1226
6b24a4b7 1227use vars qw($rcfile);
fb4d8a6c
SF
1228{
1229 my $dev_tty = (($^O eq 'VMS') ? 'TT:' : '/dev/tty');
1230 # this is the wrong metric!
1231 $rcfile = ((-e $dev_tty) ? ".perldb" : "perldb.ini");
d338d6fe
PP
1232}
1233
69893cff
RGS
1234=pod
1235
1236The debugger does a safety test of the file to be read. It must be owned
1237either by the current user or root, and must only be writable by the owner.
1238
1239=cut
1240
1241# This wraps a safety test around "do" to read and evaluate the init file.
1242#
055fd3a9
GS
1243# This isn't really safe, because there's a race
1244# between checking and opening. The solution is to
1245# open and fstat the handle, but then you have to read and
1246# eval the contents. But then the silly thing gets
69893cff
RGS
1247# your lexical scope, which is unfortunate at best.
1248sub safe_do {
055fd3a9
GS
1249 my $file = shift;
1250
1251 # Just exactly what part of the word "CORE::" don't you understand?
69893cff
RGS
1252 local $SIG{__WARN__};
1253 local $SIG{__DIE__};
055fd3a9 1254
e22ea7cc 1255 unless ( is_safe_file($file) ) {
69893cff 1256 CORE::warn <<EO_GRIPE;
055fd3a9 1257perldb: Must not source insecure rcfile $file.
b570d64b 1258 You or the superuser must be the owner, and it must not
69893cff 1259 be writable by anyone but its owner.
055fd3a9 1260EO_GRIPE
69893cff
RGS
1261 return;
1262 } ## end unless (is_safe_file($file...
055fd3a9
GS
1263
1264 do $file;
1265 CORE::warn("perldb: couldn't parse $file: $@") if $@;
69893cff 1266} ## end sub safe_do
055fd3a9 1267
69893cff
RGS
1268# This is the safety test itself.
1269#
055fd3a9
GS
1270# Verifies that owner is either real user or superuser and that no
1271# one but owner may write to it. This function is of limited use
1272# when called on a path instead of upon a handle, because there are
1273# no guarantees that filename (by dirent) whose file (by ino) is
e22ea7cc 1274# eventually accessed is the same as the one tested.
055fd3a9
GS
1275# Assumes that the file's existence is not in doubt.
1276sub is_safe_file {
1277 my $path = shift;
69893cff 1278 stat($path) || return; # mysteriously vaporized
e22ea7cc 1279 my ( $dev, $ino, $mode, $nlink, $uid, $gid ) = stat(_);
055fd3a9
GS
1280
1281 return 0 if $uid != 0 && $uid != $<;
1282 return 0 if $mode & 022;
1283 return 1;
69893cff 1284} ## end sub is_safe_file
055fd3a9 1285
69893cff 1286# If the rcfile (whichever one we decided was the right one to read)
e22ea7cc
RF
1287# exists, we safely do it.
1288if ( -f $rcfile ) {
055fd3a9 1289 safe_do("./$rcfile");
69893cff 1290}
e22ea7cc 1291
69893cff 1292# If there isn't one here, try the user's home directory.
e22ea7cc 1293elsif ( defined $ENV{HOME} && -f "$ENV{HOME}/$rcfile" ) {
055fd3a9
GS
1294 safe_do("$ENV{HOME}/$rcfile");
1295}
e22ea7cc 1296
69893cff 1297# Else try the login directory.
e22ea7cc 1298elsif ( defined $ENV{LOGDIR} && -f "$ENV{LOGDIR}/$rcfile" ) {
055fd3a9 1299 safe_do("$ENV{LOGDIR}/$rcfile");
d338d6fe
PP
1300}
1301
69893cff 1302# If the PERLDB_OPTS variable has options in it, parse those out next.
e22ea7cc
RF
1303if ( defined $ENV{PERLDB_OPTS} ) {
1304 parse_options( $ENV{PERLDB_OPTS} );
d338d6fe
PP
1305}
1306
69893cff
RGS
1307=pod
1308
1309The last thing we do during initialization is determine which subroutine is
1310to be used to obtain a new terminal when a new debugger is started. Right now,
b0b54b5e 1311the debugger only handles TCP sockets, X11, OS/2, amd Mac OS X
11653f7f 1312(darwin).
69893cff
RGS
1313
1314=cut
1315
1316# Set up the get_fork_TTY subroutine to be aliased to the proper routine.
1317# Works if you're running an xterm or xterm-like window, or you're on
6fae1ad7
RF
1318# OS/2, or on Mac OS X. This may need some expansion.
1319
1320if (not defined &get_fork_TTY) # only if no routine exists
69893cff 1321{
b570d64b 1322 if ( defined $remoteport ) {
11653f7f
JJ
1323 # Expect an inetd-like server
1324 *get_fork_TTY = \&socket_get_fork_TTY; # to listen to us
1325 }
1326 elsif (defined $ENV{TERM} # If we know what kind
6fae1ad7
RF
1327 # of terminal this is,
1328 and $ENV{TERM} eq 'xterm' # and it's an xterm,
1329 and defined $ENV{DISPLAY} # and what display it's on,
1330 )
1331 {
1332 *get_fork_TTY = \&xterm_get_fork_TTY; # use the xterm version
1333 }
1334 elsif ( $^O eq 'os2' ) { # If this is OS/2,
1335 *get_fork_TTY = \&os2_get_fork_TTY; # use the OS/2 version
1336 }
1337 elsif ( $^O eq 'darwin' # If this is Mac OS X
1338 and defined $ENV{TERM_PROGRAM} # and we're running inside
1339 and $ENV{TERM_PROGRAM}
1340 eq 'Apple_Terminal' # Terminal.app
1341 )
1342 {
1343 *get_fork_TTY = \&macosx_get_fork_TTY; # use the Mac OS X version
1344 }
69893cff 1345} ## end if (not defined &get_fork_TTY...
e22ea7cc 1346
dbb46cec
DQ
1347# untaint $^O, which may have been tainted by the last statement.
1348# see bug [perl #24674]
e22ea7cc
RF
1349$^O =~ m/^(.*)\z/;
1350$^O = $1;
f1583d8f 1351
d12a4851 1352# Here begin the unreadable code. It needs fixing.
055fd3a9 1353
69893cff
RGS
1354=head2 RESTART PROCESSING
1355
1356This section handles the restart command. When the C<R> command is invoked, it
1357tries to capture all of the state it can into environment variables, and
1358then sets C<PERLDB_RESTART>. When we start executing again, we check to see
1359if C<PERLDB_RESTART> is there; if so, we reload all the information that
1360the R command stuffed into the environment variables.
1361
b570d64b 1362 PERLDB_RESTART - flag only, contains no restart data itself.
69893cff
RGS
1363 PERLDB_HIST - command history, if it's available
1364 PERLDB_ON_LOAD - breakpoints set by the rc file
1365 PERLDB_POSTPONE - subs that have been loaded/not executed, and have actions
1366 PERLDB_VISITED - files that had breakpoints
1367 PERLDB_FILE_... - breakpoints for a file
1368 PERLDB_OPT - active options
1369 PERLDB_INC - the original @INC
1370 PERLDB_PRETYPE - preprompt debugger actions
1371 PERLDB_PRE - preprompt Perl code
1372 PERLDB_POST - post-prompt Perl code
1373 PERLDB_TYPEAHEAD - typeahead captured by readline()
1374
1375We chug through all these variables and plug the values saved in them
1376back into the appropriate spots in the debugger.
1377
1378=cut
1379
6b24a4b7
SF
1380use vars qw(@hist @truehist %postponed_file @typeahead);
1381
fb0fb5f4
SF
1382sub _restore_shared_globals_after_restart
1383{
1384 @hist = get_list('PERLDB_HIST');
1385 %break_on_load = get_list("PERLDB_ON_LOAD");
1386 %postponed = get_list("PERLDB_POSTPONE");
1387
1388 share(@hist);
1389 share(@truehist);
1390 share(%break_on_load);
1391 share(%postponed);
1392}
1393
e18a02a6 1394sub _restore_breakpoints_and_actions {
e22ea7cc 1395
e22ea7cc 1396 my @had_breakpoints = get_list("PERLDB_VISITED");
e18a02a6 1397
bdba49ad
SF
1398 for my $file_idx ( 0 .. $#had_breakpoints ) {
1399 my $filename = $had_breakpoints[$file_idx];
1400 my %pf = get_list("PERLDB_FILE_$file_idx");
1401 $postponed_file{ $filename } = \%pf if %pf;
1402 my @lines = sort {$a <=> $b} keys(%pf);
1403 my @enabled_statuses = get_list("PERLDB_FILE_ENABLED_$file_idx");
1404 for my $line_idx (0 .. $#lines) {
1405 _set_breakpoint_enabled_status(
1406 $filename,
1407 $lines[$line_idx],
1408 ($enabled_statuses[$line_idx] ? 1 : ''),
1409 );
1410 }
e22ea7cc 1411 }
69893cff 1412
e18a02a6
SF
1413 return;
1414}
1415
ca50076b
SF
1416sub _restore_options_after_restart
1417{
1418 my %options_map = get_list("PERLDB_OPT");
1419
1420 while ( my ( $opt, $val ) = each %options_map ) {
1421 $val =~ s/[\\\']/\\$1/g;
1422 parse_options("$opt'$val'");
1423 }
1424
1425 return;
1426}
1427
18580168
SF
1428sub _restore_globals_after_restart
1429{
1430 # restore original @INC
1431 @INC = get_list("PERLDB_INC");
1432 @ini_INC = @INC;
1433
1434 # return pre/postprompt actions and typeahead buffer
1435 $pretype = [ get_list("PERLDB_PRETYPE") ];
1436 $pre = [ get_list("PERLDB_PRE") ];
1437 $post = [ get_list("PERLDB_POST") ];
1438 @typeahead = get_list( "PERLDB_TYPEAHEAD", @typeahead );
1439
1440 return;
1441}
1442
fb0fb5f4 1443
e18a02a6
SF
1444if ( exists $ENV{PERLDB_RESTART} ) {
1445
1446 # We're restarting, so we don't need the flag that says to restart anymore.
1447 delete $ENV{PERLDB_RESTART};
1448
1449 # $restart = 1;
fb0fb5f4 1450 _restore_shared_globals_after_restart();
e18a02a6
SF
1451
1452 _restore_breakpoints_and_actions();
1453
69893cff 1454 # restore options
ca50076b 1455 _restore_options_after_restart();
69893cff 1456
18580168 1457 _restore_globals_after_restart();
69893cff
RGS
1458} ## end if (exists $ENV{PERLDB_RESTART...
1459
1460=head2 SETTING UP THE TERMINAL
1461
1462Now, we'll decide how the debugger is going to interact with the user.
1463If there's no TTY, we set the debugger to run non-stop; there's not going
1464to be anyone there to enter commands.
1465
1466=cut
54d04a52 1467
6b24a4b7
SF
1468use vars qw($notty $runnonstop $console $tty $LINEINFO);
1469use vars qw($lineinfo $doccmd);
1470
d338d6fe 1471if ($notty) {
69893cff 1472 $runnonstop = 1;
2cbb2ee1 1473 share($runnonstop);
69893cff 1474}
d12a4851 1475
69893cff
RGS
1476=pod
1477
1478If there is a TTY, we have to determine who it belongs to before we can
1479proceed. If this is a slave editor or graphical debugger (denoted by
1480the first command-line switch being '-emacs'), we shift this off and
1481set C<$rl> to 0 (XXX ostensibly to do straight reads).
1482
1483=cut
1484
1485else {
e22ea7cc 1486
69893cff
RGS
1487 # Is Perl being run from a slave editor or graphical debugger?
1488 # If so, don't use readline, and set $slave_editor = 1.
2b0b9dd1
SF
1489 if ($slave_editor = ( @main::ARGV && ( $main::ARGV[0] eq '-emacs' ) )) {
1490 $rl = 0;
1491 shift(@main::ARGV);
1492 }
e22ea7cc
RF
1493
1494 #require Term::ReadLine;
d12a4851 1495
69893cff
RGS
1496=pod
1497
1498We then determine what the console should be on various systems:
1499
1500=over 4
1501
1502=item * Cygwin - We use C<stdin> instead of a separate device.
1503
1504=cut
1505
e22ea7cc
RF
1506 if ( $^O eq 'cygwin' ) {
1507
69893cff
RGS
1508 # /dev/tty is binary. use stdin for textmode
1509 undef $console;
1510 }
1511
1512=item * Unix - use C</dev/tty>.
1513
1514=cut
1515
e22ea7cc 1516 elsif ( -e "/dev/tty" ) {
69893cff
RGS
1517 $console = "/dev/tty";
1518 }
1519
1520=item * Windows or MSDOS - use C<con>.
1521
1522=cut
1523
e22ea7cc 1524 elsif ( $^O eq 'dos' or -e "con" or $^O eq 'MSWin32' ) {
69893cff
RGS
1525 $console = "con";
1526 }
1527
69893cff
RGS
1528=item * VMS - use C<sys$command>.
1529
1530=cut
1531
1532 else {
e22ea7cc 1533
69893cff
RGS
1534 # everything else is ...
1535 $console = "sys\$command";
d12a4851 1536 }
69893cff
RGS
1537
1538=pod
1539
1540=back
1541
1542Several other systems don't use a specific console. We C<undef $console>
1543for those (Windows using a slave editor/graphical debugger, NetWare, OS/2
1544with a slave editor, Epoc).
1545
1546=cut
d12a4851 1547
e22ea7cc
RF
1548 if ( ( $^O eq 'MSWin32' ) and ( $slave_editor or defined $ENV{EMACS} ) ) {
1549
69893cff 1550 # /dev/tty is binary. use stdin for textmode
e22ea7cc
RF
1551 $console = undef;
1552 }
1553
1554 if ( $^O eq 'NetWare' ) {
d12a4851 1555
69893cff
RGS
1556 # /dev/tty is binary. use stdin for textmode
1557 $console = undef;
1558 }
d12a4851 1559
69893cff
RGS
1560 # In OS/2, we need to use STDIN to get textmode too, even though
1561 # it pretty much looks like Unix otherwise.
e22ea7cc
RF
1562 if ( defined $ENV{OS2_SHELL} and ( $slave_editor or $ENV{WINDOWID} ) )
1563 { # In OS/2
1564 $console = undef;
1565 }
1566
1567 # EPOC also falls into the 'got to use STDIN' camp.
1568 if ( $^O eq 'epoc' ) {
1569 $console = undef;
1570 }
d12a4851 1571
69893cff
RGS
1572=pod
1573
1574If there is a TTY hanging around from a parent, we use that as the console.
1575
1576=cut
1577
e22ea7cc 1578 $console = $tty if defined $tty;
d12a4851 1579
b570d64b 1580=head2 SOCKET HANDLING
69893cff
RGS
1581
1582The debugger is capable of opening a socket and carrying out a debugging
1583session over the socket.
1584
1585If C<RemotePort> was defined in the options, the debugger assumes that it
1586should try to start a debugging session on that port. It builds the socket
1587and then tries to connect the input and output filehandles to it.
1588
1589=cut
1590
1591 # Handle socket stuff.
e22ea7cc
RF
1592
1593 if ( defined $remoteport ) {
1594
69893cff
RGS
1595 # If RemotePort was defined in the options, connect input and output
1596 # to the socket.
11653f7f 1597 $IN = $OUT = connect_remoteport();
69893cff
RGS
1598 } ## end if (defined $remoteport)
1599
1600=pod
1601
1602If no C<RemotePort> was defined, and we want to create a TTY on startup,
1603this is probably a situation where multiple debuggers are running (for example,
1604a backticked command that starts up another debugger). We create a new IN and
1605OUT filehandle, and do the necessary mojo to create a new TTY if we know how
1606and if we can.
1607
1608=cut
1609
1610 # Non-socket.
1611 else {
e22ea7cc 1612
69893cff
RGS
1613 # Two debuggers running (probably a system or a backtick that invokes
1614 # the debugger itself under the running one). create a new IN and OUT
e22ea7cc 1615 # filehandle, and do the necessary mojo to create a new tty if we
69893cff 1616 # know how, and we can.
e22ea7cc
RF
1617 create_IN_OUT(4) if $CreateTTY & 4;
1618 if ($console) {
1619
69893cff 1620 # If we have a console, check to see if there are separate ins and
cd1191f1 1621 # outs to open. (They are assumed identical if not.)
69893cff 1622
e22ea7cc
RF
1623 my ( $i, $o ) = split /,/, $console;
1624 $o = $i unless defined $o;
69893cff 1625
69893cff 1626 # read/write on in, or just read, or read on STDIN.
e22ea7cc
RF
1627 open( IN, "+<$i" )
1628 || open( IN, "<$i" )
1629 || open( IN, "<&STDIN" );
1630
69893cff
RGS
1631 # read/write/create/clobber out, or write/create/clobber out,
1632 # or merge with STDERR, or merge with STDOUT.
e22ea7cc
RF
1633 open( OUT, "+>$o" )
1634 || open( OUT, ">$o" )
1635 || open( OUT, ">&STDERR" )
1636 || open( OUT, ">&STDOUT" ); # so we don't dongle stdout
1637
1638 } ## end if ($console)
1639 elsif ( not defined $console ) {
1640
1641 # No console. Open STDIN.
1642 open( IN, "<&STDIN" );
1643
1644 # merge with STDERR, or with STDOUT.
1645 open( OUT, ">&STDERR" )
1646 || open( OUT, ">&STDOUT" ); # so we don't dongle stdout
1647 $console = 'STDIN/OUT';
69893cff
RGS
1648 } ## end elsif (not defined $console)
1649
1650 # Keep copies of the filehandles so that when the pager runs, it
1651 # can close standard input without clobbering ours.
2b0b9dd1
SF
1652 if ($console or (not defined($console))) {
1653 $IN = \*IN;
1654 $OUT = \*OUT;
1655 }
e22ea7cc
RF
1656 } ## end elsif (from if(defined $remoteport))
1657
1658 # Unbuffer DB::OUT. We need to see responses right away.
70c9432b 1659 $OUT->autoflush(1);
e22ea7cc
RF
1660
1661 # Line info goes to debugger output unless pointed elsewhere.
1662 # Pointing elsewhere makes it possible for slave editors to
1663 # keep track of file and position. We have both a filehandle
1664 # and a I/O description to keep track of.
1665 $LINEINFO = $OUT unless defined $LINEINFO;
1666 $lineinfo = $console unless defined $lineinfo;
2cbb2ee1 1667 # share($LINEINFO); # <- unable to share globs
b570d64b 1668 share($lineinfo); #
e22ea7cc 1669
69893cff
RGS
1670=pod
1671
1672To finish initialization, we show the debugger greeting,
1673and then call the C<afterinit()> subroutine if there is one.
1674
1675=cut
d12a4851 1676
e22ea7cc
RF
1677 # Show the debugger greeting.
1678 $header =~ s/.Header: ([^,]+),v(\s+\S+\s+\S+).*$/$1$2/;
1679 unless ($runnonstop) {
1680 local $\ = '';
1681 local $, = '';
1682 if ( $term_pid eq '-1' ) {
1683 print $OUT "\nDaughter DB session started...\n";
1684 }
1685 else {
1686 print $OUT "\nLoading DB routines from $header\n";
1687 print $OUT (
1688 "Editor support ",
1689 $slave_editor ? "enabled" : "available", ".\n"
1690 );
1691 print $OUT
1f874cb6 1692"\nEnter h or 'h h' for help, or '$doccmd perldebug' for more help.\n\n";
69893cff
RGS
1693 } ## end else [ if ($term_pid eq '-1')
1694 } ## end unless ($runnonstop)
1695} ## end else [ if ($notty)
1696
1697# XXX This looks like a bug to me.
1698# Why copy to @ARGS and then futz with @args?
d338d6fe 1699@ARGS = @ARGV;
6b24a4b7 1700# for (@args) {
69893cff
RGS
1701 # Make sure backslashes before single quotes are stripped out, and
1702 # keep args unless they are numeric (XXX why?)
e22ea7cc
RF
1703 # s/\'/\\\'/g; # removed while not justified understandably
1704 # s/(.*)/'$1'/ unless /^-?[\d.]+$/; # ditto
6b24a4b7 1705# }
d338d6fe 1706
e22ea7cc 1707# If there was an afterinit() sub defined, call it. It will get
69893cff 1708# executed in our scope, so it can fiddle with debugger globals.
e22ea7cc 1709if ( defined &afterinit ) { # May be defined in $rcfile
2b0b9dd1 1710 afterinit();
d338d6fe 1711}
e22ea7cc 1712
69893cff 1713# Inform us about "Stack dump during die enabled ..." in dieLevel().
6b24a4b7
SF
1714use vars qw($I_m_init);
1715
43aed9ee
IZ
1716$I_m_init = 1;
1717
d338d6fe
PP
1718############################################################ Subroutines
1719
69893cff
RGS
1720=head1 SUBROUTINES
1721
1722=head2 DB
1723
1724This gigantic subroutine is the heart of the debugger. Called before every
1725statement, its job is to determine if a breakpoint has been reached, and
1726stop if so; read commands from the user, parse them, and execute
b468dcb6 1727them, and then send execution off to the next statement.
69893cff
RGS
1728
1729Note that the order in which the commands are processed is very important;
1730some commands earlier in the loop will actually alter the C<$cmd> variable
be9a9b1d 1731to create other commands to be executed later. This is all highly I<optimized>
69893cff
RGS
1732but can be confusing. Check the comments for each C<$cmd ... && do {}> to
1733see what's happening in any given command.
1734
1735=cut
1736
6b24a4b7
SF
1737use vars qw(
1738 $action
1739 %alias
1740 $cmd
1741 $doret
1742 $fall_off_end
1743 $file
1744 $filename_ini
1745 $finished
1746 %had_breakpoints
1747 $incr
1748 $laststep
1749 $level
1750 $max
1751 @old_watch
1752 $package
1753 $rc
1754 $sh
1755 @stack
1756 $stack_depth
1757 @to_watch
1758 $try
2c247e84 1759 $end
6b24a4b7
SF
1760);
1761
2b0b9dd1
SF
1762sub _DB_on_init__initialize_globals
1763{
69893cff 1764 # Check for whether we should be running continuously or not.
36477c24 1765 # _After_ the perl program is compiled, $single is set to 1:
e22ea7cc
RF
1766 if ( $single and not $second_time++ ) {
1767
69893cff 1768 # Options say run non-stop. Run until we get an interrupt.
e22ea7cc
RF
1769 if ($runnonstop) { # Disable until signal
1770 # If there's any call stack in place, turn off single
1771 # stepping into subs throughout the stack.
2c247e84 1772 for my $i (0 .. $stack_depth) {
72d7d80d 1773 $stack[ $i ] &= ~1;
e22ea7cc
RF
1774 }
1775
69893cff 1776 # And we are now no longer in single-step mode.
e22ea7cc 1777 $single = 0;
69893cff
RGS
1778
1779 # If we simply returned at this point, we wouldn't get
1780 # the trace info. Fall on through.
e22ea7cc 1781 # return;
69893cff
RGS
1782 } ## end if ($runnonstop)
1783
e22ea7cc
RF
1784 elsif ($ImmediateStop) {
1785
1786 # We are supposed to stop here; XXX probably a break.
1787 $ImmediateStop = 0; # We've processed it; turn it off
1788 $signal = 1; # Simulate an interrupt to force
1789 # us into the command loop
69893cff
RGS
1790 }
1791 } ## end if ($single and not $second_time...
1792
1793 # If we're in single-step mode, or an interrupt (real or fake)
1794 # has occurred, turn off non-stop mode.
1795 $runnonstop = 0 if $single or $signal;
1796
2b0b9dd1
SF
1797 return;
1798}
1799
6791e41b
SF
1800sub _DB__determine_if_we_should_break
1801{
1802 # if we have something here, see if we should break.
1803 # $stop is lexical and local to this block - $action on the other hand
1804 # is global.
1805 my $stop;
1806
1807 if ( $dbline{$line}
1808 && _is_breakpoint_enabled($filename, $line)
1809 && (( $stop, $action ) = split( /\0/, $dbline{$line} ) ) )
1810 {
1811
1812 # Stop if the stop criterion says to just stop.
1813 if ( $stop eq '1' ) {
1814 $signal |= 1;
1815 }
1816
1817 # It's a conditional stop; eval it in the user's context and
1818 # see if we should stop. If so, remove the one-time sigil.
1819 elsif ($stop) {
1820 $evalarg = "\$DB::signal |= 1 if do {$stop}";
1821 &eval;
1822 # If the breakpoint is temporary, then delete its enabled status.
1823 if ($dbline{$line} =~ s/;9($|\0)/$1/) {
1824 _cancel_breakpoint_temp_enabled_status($filename, $line);
1825 }
1826 }
1827 } ## end if ($dbline{$line} && ...
1828}
1829
2b0b9dd1
SF
1830sub DB {
1831
1832 # lock the debugger and get the thread id for the prompt
1833 lock($DBGR);
1834 my $tid;
1835 my $position;
1836 my ($prefix, $after, $infix);
1837 my $pat;
1838
1839 if ($ENV{PERL5DB_THREADED}) {
1840 $tid = eval { "[".threads->tid."]" };
1841 }
1842
1843 _DB_on_init__initialize_globals();
1844
69893cff
RGS
1845 # Preserve current values of $@, $!, $^E, $,, $/, $\, $^W.
1846 # The code being debugged may have altered them.
d338d6fe 1847 &save;
69893cff
RGS
1848
1849 # Since DB::DB gets called after every line, we can use caller() to
1850 # figure out where we last were executing. Sneaky, eh? This works because
e22ea7cc 1851 # caller is returning all the extra information when called from the
69893cff 1852 # debugger.
e22ea7cc 1853 local ( $package, $filename, $line ) = caller;
6b24a4b7 1854 $filename_ini = $filename;
69893cff
RGS
1855
1856 # set up the context for DB::eval, so it can properly execute
1857 # code on behalf of the user. We add the package in so that the
1858 # code is eval'ed in the proper package (not in the debugger!).
6b24a4b7 1859 local $usercontext = _calc_usercontext($package);
69893cff
RGS
1860
1861 # Create an alias to the active file magical array to simplify
1862 # the code here.
e22ea7cc 1863 local (*dbline) = $main::{ '_<' . $filename };
aa057b67 1864
69893cff 1865 # Last line in the program.
55783941 1866 $max = $#dbline;
69893cff 1867
6791e41b 1868 _DB__determine_if_we_should_break();
69893cff
RGS
1869
1870 # Preserve the current stop-or-not, and see if any of the W
1871 # (watch expressions) has changed.
36477c24 1872 my $was_signal = $signal;
69893cff
RGS
1873
1874 # If we have any watch expressions ...
e22ea7cc 1875 if ( $trace & 2 ) {
2c247e84 1876 for my $n (0 .. $#to_watch) {
e22ea7cc
RF
1877 $evalarg = $to_watch[$n];
1878 local $onetimeDump; # Tell DB::eval() to not output results
69893cff
RGS
1879
1880 # Fix context DB::eval() wants to return an array, but
1881 # we need a scalar here.
e22ea7cc
RF
1882 my ($val) = join( "', '", &eval );
1883 $val = ( ( defined $val ) ? "'$val'" : 'undef' );
69893cff
RGS
1884
1885 # Did it change?
e22ea7cc
RF
1886 if ( $val ne $old_watch[$n] ) {
1887
69893cff 1888 # Yep! Show the difference, and fake an interrupt.
e22ea7cc
RF
1889 $signal = 1;
1890 print $OUT <<EOP;
405ff068 1891Watchpoint $n:\t$to_watch[$n] changed:
69893cff
RGS
1892 old value:\t$old_watch[$n]
1893 new value:\t$val
6027b9a3 1894EOP
e22ea7cc 1895 $old_watch[$n] = $val;
69893cff 1896 } ## end if ($val ne $old_watch...
2c247e84 1897 } ## end for my $n (0 ..
69893cff
RGS
1898 } ## end if ($trace & 2)
1899
1900=head2 C<watchfunction()>
1901
1902C<watchfunction()> is a function that can be defined by the user; it is a
b570d64b 1903function which will be run on each entry to C<DB::DB>; it gets the
69893cff
RGS
1904current package, filename, and line as its parameters.
1905
b570d64b 1906The watchfunction can do anything it likes; it is executing in the
69893cff
RGS
1907debugger's context, so it has access to all of the debugger's internal
1908data structures and functions.
1909
1910C<watchfunction()> can control the debugger's actions. Any of the following
1911will cause the debugger to return control to the user's program after
1912C<watchfunction()> executes:
1913
b570d64b 1914=over 4
69893cff 1915
be9a9b1d
AT
1916=item *
1917
1918Returning a false value from the C<watchfunction()> itself.
1919
1920=item *
1921
1922Altering C<$single> to a false value.
1923
1924=item *
69893cff 1925
be9a9b1d 1926Altering C<$signal> to a false value.
69893cff 1927
be9a9b1d 1928=item *
69893cff 1929
be9a9b1d 1930Turning off the C<4> bit in C<$trace> (this also disables the
69893cff
RGS
1931check for C<watchfunction()>. This can be done with
1932
1933 $trace &= ~4;
1934
1935=back
1936
1937=cut
1938
e22ea7cc 1939 # If there's a user-defined DB::watchfunction, call it with the
69893cff
RGS
1940 # current package, filename, and line. The function executes in
1941 # the DB:: package.
e22ea7cc
RF
1942 if ( $trace & 4 ) { # User-installed watch
1943 return
1944 if watchfunction( $package, $filename, $line )
1945 and not $single
1946 and not $was_signal
1947 and not( $trace & ~4 );
69893cff
RGS
1948 } ## end if ($trace & 4)
1949
e22ea7cc 1950 # Pick up any alteration to $signal in the watchfunction, and
69893cff 1951 # turn off the signal now.
6027b9a3 1952 $was_signal = $signal;
69893cff
RGS
1953 $signal = 0;
1954
1955=head2 GETTING READY TO EXECUTE COMMANDS
1956
1957The debugger decides to take control if single-step mode is on, the
1958C<t> command was entered, or the user generated a signal. If the program
1959has fallen off the end, we set things up so that entering further commands
1960won't cause trouble, and we say that the program is over.
1961
1962=cut
1963
8dc67a69
SF
1964 # Make sure that we always print if asked for explicitly regardless
1965 # of $trace_to_depth .
1966 my $explicit_stop = ($single || $was_signal);
1967
69893cff
RGS
1968 # Check to see if we should grab control ($single true,
1969 # trace set appropriately, or we got a signal).
8dc67a69 1970 if ( $explicit_stop || ( $trace & 1 ) ) {
e22ea7cc 1971
69893cff 1972 # Yes, grab control.
e22ea7cc
RF
1973 if ($slave_editor) {
1974
69893cff 1975 # Tell the editor to update its position.
e22ea7cc
RF
1976 $position = "\032\032$filename:$line:0\n";
1977 print_lineinfo($position);
1978 }
69893cff
RGS
1979
1980=pod
1981
b570d64b 1982Special check: if we're in package C<DB::fake>, we've gone through the
69893cff
RGS
1983C<END> block at least once. We set up everything so that we can continue
1984to enter commands and have a valid context to be in.
1985
1986=cut
1987
e22ea7cc 1988 elsif ( $package eq 'DB::fake' ) {
69893cff 1989
69893cff 1990 # Fallen off the end already.
e22ea7cc
RF
1991 $term || &setterm;
1992 print_help(<<EOP);
405ff068 1993Debugged program terminated. Use B<q> to quit or B<R> to restart,
6b27b0a0 1994 use B<o> I<inhibit_exit> to avoid stopping after program termination,
b570d64b 1995 B<h q>, B<h R> or B<h o> to get additional info.
405ff068 1996EOP
e22ea7cc 1997
69893cff 1998 # Set the DB::eval context appropriately.
e22ea7cc 1999 $package = 'main';
6b24a4b7 2000 $usercontext = _calc_usercontext($package);
69893cff 2001 } ## end elsif ($package eq 'DB::fake')
e219e2fb 2002
69893cff 2003=pod
e219e2fb 2004
69893cff
RGS
2005If the program hasn't finished executing, we scan forward to the
2006next executable line, print that out, build the prompt from the file and line
b570d64b 2007number information, and print that.
e219e2fb 2008
69893cff
RGS
2009=cut
2010
e22ea7cc
RF
2011 else {
2012
8dc67a69 2013
69893cff
RGS
2014 # Still somewhere in the midst of execution. Set up the
2015 # debugger prompt.
2016 $sub =~ s/\'/::/; # Swap Perl 4 package separators (') to
e22ea7cc 2017 # Perl 5 ones (sorry, we don't print Klingon
69893cff
RGS
2018 #module names)
2019
6b24a4b7 2020 $prefix = $sub =~ /::/ ? "" : ($package . '::');
e22ea7cc
RF
2021 $prefix .= "$sub($filename:";
2022 $after = ( $dbline[$line] =~ /\n$/ ? '' : "\n" );
69893cff
RGS
2023
2024 # Break up the prompt if it's really long.
e22ea7cc
RF
2025 if ( length($prefix) > 30 ) {
2026 $position = "$prefix$line):\n$line:\t$dbline[$line]$after";
2027 $prefix = "";
2028 $infix = ":\t";
2029 }
2030 else {
2031 $infix = "):\t";
2032 $position = "$prefix$line$infix$dbline[$line]$after";
2033 }
69893cff
RGS
2034
2035 # Print current line info, indenting if necessary.
e22ea7cc
RF
2036 if ($frame) {
2037 print_lineinfo( ' ' x $stack_depth,
2038 "$line:\t$dbline[$line]$after" );
2039 }
2040 else {
8dc67a69 2041 depth_print_lineinfo($explicit_stop, $position);
e22ea7cc 2042 }
69893cff
RGS
2043
2044 # Scan forward, stopping at either the end or the next
2045 # unbreakable line.
72d7d80d 2046 for ( my $i = $line + 1 ; $i <= $max && $dbline[$i] == 0 ; ++$i )
e22ea7cc 2047 { #{ vi
69893cff
RGS
2048
2049 # Drop out on null statements, block closers, and comments.
2050 last if $dbline[$i] =~ /^\s*[\;\}\#\n]/;
2051
2052 # Drop out if the user interrupted us.
2053 last if $signal;
2054
2055 # Append a newline if the line doesn't have one. Can happen
2056 # in eval'ed text, for instance.
e22ea7cc 2057 $after = ( $dbline[$i] =~ /\n$/ ? '' : "\n" );
69893cff
RGS
2058
2059 # Next executable line.
6b24a4b7 2060 my $incr_pos = "$prefix$i$infix$dbline[$i]$after";
69893cff
RGS
2061 $position .= $incr_pos;
2062 if ($frame) {
e22ea7cc 2063
69893cff 2064 # Print it indented if tracing is on.
e22ea7cc
RF
2065 print_lineinfo( ' ' x $stack_depth,
2066 "$i:\t$dbline[$i]$after" );
69893cff
RGS
2067 }
2068 else {
8dc67a69 2069 depth_print_lineinfo($explicit_stop, $incr_pos);
69893cff 2070 }
72d7d80d 2071 } ## end for ($i = $line + 1 ; $i...
69893cff
RGS
2072 } ## end else [ if ($slave_editor)
2073 } ## end if ($single || ($trace...
2074
2075=pod
2076
2077If there's an action to be executed for the line we stopped at, execute it.
b570d64b 2078If there are any preprompt actions, execute those as well.
e219e2fb
RF
2079
2080=cut
2081
69893cff
RGS
2082 # If there's an action, do it now.
2083 $evalarg = $action, &eval if $action;
e219e2fb 2084
69893cff
RGS
2085 # Are we nested another level (e.g., did we evaluate a function
2086 # that had a breakpoint in it at the debugger prompt)?
e22ea7cc
RF
2087 if ( $single || $was_signal ) {
2088
69893cff 2089 # Yes, go down a level.
e22ea7cc 2090 local $level = $level + 1;
69893cff
RGS
2091
2092 # Do any pre-prompt actions.
e22ea7cc
RF
2093 foreach $evalarg (@$pre) {
2094 &eval;
2095 }
69893cff
RGS
2096
2097 # Complain about too much recursion if we passed the limit.
e22ea7cc 2098 print $OUT $stack_depth . " levels deep in subroutine calls!\n"
69893cff
RGS
2099 if $single & 4;
2100
2101 # The line we're currently on. Set $incr to -1 to stay here
2102 # until we get a command that tells us to advance.
e22ea7cc
RF
2103 $start = $line;
2104 $incr = -1; # for backward motion.
69893cff
RGS
2105
2106 # Tack preprompt debugger actions ahead of any actual input.
e22ea7cc 2107 @typeahead = ( @$pretype, @typeahead );
69893cff
RGS
2108
2109=head2 WHERE ARE WE?
2110
2111XXX Relocate this section?
2112
2113The debugger normally shows the line corresponding to the current line of
2114execution. Sometimes, though, we want to see the next line, or to move elsewhere
2115in the file. This is done via the C<$incr>, C<$start>, and C<$max> variables.
2116
be9a9b1d
AT
2117C<$incr> controls by how many lines the I<current> line should move forward
2118after a command is executed. If set to -1, this indicates that the I<current>
69893cff
RGS
2119line shouldn't change.
2120
be9a9b1d 2121C<$start> is the I<current> line. It is used for things like knowing where to
69893cff
RGS
2122move forwards or backwards from when doing an C<L> or C<-> command.
2123
2124C<$max> tells the debugger where the last line of the current file is. It's
2125used to terminate loops most often.
2126
2127=head2 THE COMMAND LOOP
2128
2129Most of C<DB::DB> is actually a command parsing and dispatch loop. It comes
2130in two parts:
2131
2132=over 4
2133
be9a9b1d
AT
2134=item *
2135
2136The outer part of the loop, starting at the C<CMD> label. This loop
69893cff
RGS
2137reads a command and then executes it.
2138
be9a9b1d
AT
2139=item *
2140
2141The inner part of the loop, starting at the C<PIPE> label. This part
69893cff
RGS
2142is wholly contained inside the C<CMD> block and only executes a command.
2143Used to handle commands running inside a pager.
2144
2145=back
2146
2147So why have two labels to restart the loop? Because sometimes, it's easier to
2148have a command I<generate> another command and then re-execute the loop to do
2149the new command. This is faster, but perhaps a bit more convoluted.
2150
2151=cut
2152
2153 # The big command dispatch loop. It keeps running until the
2154 # user yields up control again.
2155 #
2156 # If we have a terminal for input, and we get something back
2157 # from readline(), keep on processing.
6b24a4b7
SF
2158 my $piped;
2159 my $selected;
2160
e22ea7cc
RF
2161 CMD:
2162 while (
2163
69893cff 2164 # We have a terminal, or can get one ...
e22ea7cc
RF
2165 ( $term || &setterm ),
2166
69893cff 2167 # ... and it belogs to this PID or we get one for this PID ...
e22ea7cc
RF
2168 ( $term_pid == $$ or resetterm(1) ),
2169
69893cff 2170 # ... and we got a line of command input ...
e22ea7cc
RF
2171 defined(
2172 $cmd = &readline(
2cbb2ee1 2173 "$pidprompt $tid DB"
e22ea7cc
RF
2174 . ( '<' x $level )
2175 . ( $#hist + 1 )
2176 . ( '>' x $level ) . " "
69893cff
RGS
2177 )
2178 )
2179 )
2180 {
e22ea7cc 2181
2cbb2ee1 2182 share($cmd);
69893cff
RGS
2183 # ... try to execute the input as debugger commands.
2184
2185 # Don't stop running.
2186 $single = 0;
2187
2188 # No signal is active.
2189 $signal = 0;
2190
2191 # Handle continued commands (ending with \):
3d7a2a93 2192 if ($cmd =~ s/\\\z/\n/) {
e22ea7cc
RF
2193 $cmd .= &readline(" cont: ");
2194 redo CMD;
3d7a2a93 2195 }
69893cff
RGS
2196
2197=head4 The null command
2198
be9a9b1d 2199A newline entered by itself means I<re-execute the last command>. We grab the
69893cff
RGS
2200command out of C<$laststep> (where it was recorded previously), and copy it
2201back into C<$cmd> to be executed below. If there wasn't any previous command,
2202we'll do nothing below (no command will match). If there was, we also save it
2203in the command history and fall through to allow the command parsing to pick
2204it up.
2205
2206=cut
2207
2208 # Empty input means repeat the last command.
e22ea7cc
RF
2209 $cmd =~ /^$/ && ( $cmd = $laststep );
2210 chomp($cmd); # get rid of the annoying extra newline
2211 push( @hist, $cmd ) if length($cmd) > 1;
2212 push( @truehist, $cmd );
2cbb2ee1
RGS
2213 share(@hist);
2214 share(@truehist);
e22ea7cc
RF
2215
2216 # This is a restart point for commands that didn't arrive
2217 # via direct user input. It allows us to 'redo PIPE' to
2218 # re-execute command processing without reading a new command.
69893cff 2219 PIPE: {
e22ea7cc
RF
2220 $cmd =~ s/^\s+//s; # trim annoying leading whitespace
2221 $cmd =~ s/\s+$//s; # trim annoying trailing whitespace
6b24a4b7 2222 my ($i) = split( /\s+/, $cmd );
69893cff
RGS
2223
2224=head3 COMMAND ALIASES
2225
2226The debugger can create aliases for commands (these are stored in the
2227C<%alias> hash). Before a command is executed, the command loop looks it up
2228in the alias hash and substitutes the contents of the alias for the command,
2229completely replacing it.
2230
2231=cut
2232
2233 # See if there's an alias for the command, and set it up if so.
e22ea7cc
RF
2234 if ( $alias{$i} ) {
2235
69893cff
RGS
2236 # Squelch signal handling; we want to keep control here
2237 # if something goes loco during the alias eval.
2238 local $SIG{__DIE__};
2239 local $SIG{__WARN__};
2240
2241 # This is a command, so we eval it in the DEBUGGER's
2242 # scope! Otherwise, we can't see the special debugger
2243 # variables, or get to the debugger's subs. (Well, we
2244 # _could_, but why make it even more complicated?)
2245 eval "\$cmd =~ $alias{$i}";
2246 if ($@) {
2247 local $\ = '';
1f874cb6 2248 print $OUT "Couldn't evaluate '$i' alias: $@";
69893cff
RGS
2249 next CMD;
2250 }
2251 } ## end if ($alias{$i})
2252
2253=head3 MAIN-LINE COMMANDS
2254
2255All of these commands work up to and after the program being debugged has
b570d64b 2256terminated.
69893cff
RGS
2257
2258=head4 C<q> - quit
2259
b570d64b 2260Quit the debugger. This entails setting the C<$fall_off_end> flag, so we don't
69893cff
RGS
2261try to execute further, cleaning any restart-related stuff out of the
2262environment, and executing with the last value of C<$?>.
2263
2264=cut
2265
3d7a2a93 2266 if ($cmd eq 'q') {
69893cff
RGS
2267 $fall_off_end = 1;
2268 clean_ENV();
2269 exit $?;
3d7a2a93 2270 }
69893cff 2271
611272bb 2272=head4 C<t> - trace [n]
69893cff
RGS
2273
2274Turn tracing on or off. Inverts the appropriate bit in C<$trace> (q.v.).
611272bb 2275If level is specified, set C<$trace_to_depth>.
69893cff
RGS
2276
2277=cut
2278
3d7a2a93 2279 if (my ($levels) = $cmd =~ /\At(?:\s+(\d+))?\z/) {
e22ea7cc
RF
2280 $trace ^= 1;
2281 local $\ = '';
611272bb 2282 $trace_to_depth = $levels ? $stack_depth + $levels : 1E9;
e22ea7cc 2283 print $OUT "Trace = "
611272bb
PS
2284 . ( ( $trace & 1 )
2285 ? ( $levels ? "on (to level $trace_to_depth)" : "on" )
2286 : "off" ) . "\n";
e22ea7cc 2287 next CMD;
3d7a2a93 2288 }
69893cff
RGS
2289
2290=head4 C<S> - list subroutines matching/not matching a pattern
2291
2292Walks through C<%sub>, checking to see whether or not to print the name.
2293
2294=cut
2295
826b9a2e
SF
2296 if (my ($print_all_subs, $should_reverse, $Spatt)
2297 = $cmd =~ /\AS(\s+(!)?(.+))?\z/) {
2298 # $Spatt is the pattern (if any) to use.
2299 # Reverse scan?
2300 my $Srev = defined $should_reverse;
2301 # No args - print all subs.
2302 my $Snocheck = !defined $print_all_subs;
69893cff
RGS
2303
2304 # Need to make these sane here.
e22ea7cc
RF
2305 local $\ = '';
2306 local $, = '';
69893cff
RGS
2307
2308 # Search through the debugger's magical hash of subs.
2309 # If $nocheck is true, just print the sub name.
2310 # Otherwise, check it against the pattern. We then use
2311 # the XOR trick to reverse the condition as required.
e22ea7cc
RF
2312 foreach $subname ( sort( keys %sub ) ) {
2313 if ( $Snocheck or $Srev ^ ( $subname =~ /$Spatt/ ) ) {
2314 print $OUT $subname, "\n";
2315 }
2316 }
2317 next CMD;
826b9a2e 2318 }
69893cff
RGS
2319
2320=head4 C<X> - list variables in current package
2321
b570d64b 2322Since the C<V> command actually processes this, just change this to the
69893cff
RGS
2323appropriate C<V> command and fall through.
2324
2325=cut
2326
e22ea7cc 2327 $cmd =~ s/^X\b/V $package/;
69893cff
RGS
2328
2329=head4 C<V> - list variables
2330
b570d64b 2331Uses C<dumpvar.pl> to dump out the current values for selected variables.
69893cff
RGS
2332
2333=cut
2334
2335 # Bare V commands get the currently-being-debugged package
2336 # added.
826b9a2e 2337 if ($cmd eq "V") {
e22ea7cc 2338 $cmd = "V $package";
826b9a2e 2339 }
69893cff
RGS
2340
2341 # V - show variables in package.
826b9a2e
SF
2342 if (my ($new_packname, $new_vars_str) =
2343 $cmd =~ /\AV\b\s*(\S+)\s*(.*)/) {
e22ea7cc 2344
69893cff
RGS
2345 # Save the currently selected filehandle and
2346 # force output to debugger's filehandle (dumpvar
2347 # just does "print" for output).
6b24a4b7 2348 my $savout = select($OUT);
69893cff
RGS
2349
2350 # Grab package name and variables to dump.
826b9a2e
SF
2351 $packname = $new_packname;
2352 my @vars = split( ' ', $new_vars_str );
69893cff
RGS
2353
2354 # If main::dumpvar isn't here, get it.
e81465be 2355 do 'dumpvar.pl' || die $@ unless defined &main::dumpvar;
e22ea7cc
RF
2356 if ( defined &main::dumpvar ) {
2357
69893cff
RGS
2358 # We got it. Turn off subroutine entry/exit messages
2359 # for the moment, along with return values.
e22ea7cc
RF
2360 local $frame = 0;
2361 local $doret = -2;
69893cff
RGS
2362
2363 # must detect sigpipe failures - not catching
2364 # then will cause the debugger to die.
2365 eval {
2366 &main::dumpvar(
2367 $packname,
2368 defined $option{dumpDepth}
e22ea7cc
RF
2369 ? $option{dumpDepth}
2370 : -1, # assume -1 unless specified
69893cff 2371 @vars
e22ea7cc
RF
2372 );
2373 };
2374
2375 # The die doesn't need to include the $@, because
2376 # it will automatically get propagated for us.
2377 if ($@) {
2378 die unless $@ =~ /dumpvar print failed/;
2379 }
2380 } ## end if (defined &main::dumpvar)
2381 else {
2382
2383 # Couldn't load dumpvar.
2384 print $OUT "dumpvar.pl not available.\n";
2385 }
69893cff 2386
69893cff 2387 # Restore the output filehandle, and go round again.
e22ea7cc
RF
2388 select($savout);
2389 next CMD;
826b9a2e 2390 }
69893cff
RGS
2391
2392=head4 C<x> - evaluate and print an expression
2393
2394Hands the expression off to C<DB::eval>, setting it up to print the value
2395via C<dumpvar.pl> instead of just printing it directly.
2396
2397=cut
2398
826b9a2e 2399 if ($cmd =~ s#\Ax\b# #) { # Remainder gets done by DB::eval()
e22ea7cc 2400 $onetimeDump = 'dump'; # main::dumpvar shows the output
69893cff
RGS
2401
2402 # handle special "x 3 blah" syntax XXX propagate
2403 # doc back to special variables.
826b9a2e 2404 if ( $cmd =~ s#\A\s*(\d+)(?=\s)# #) {
e22ea7cc
RF
2405 $onetimedumpDepth = $1;
2406 }
826b9a2e 2407 }
69893cff
RGS
2408
2409=head4 C<m> - print methods
2410
2411Just uses C<DB::methods> to determine what methods are available.
2412
2413=cut
2414
826b9a2e 2415 if ($cmd =~ s#\Am\s+([\w:]+)\s*\z# #) {
e22ea7cc
RF
2416 methods($1);
2417 next CMD;
826b9a2e 2418 }
69893cff
RGS
2419
2420 # m expr - set up DB::eval to do the work
826b9a2e 2421 if ($cmd =~ s#\Am\b# #) { # Rest gets done by DB::eval()
e22ea7cc 2422 $onetimeDump = 'methods'; # method output gets used there
826b9a2e 2423 }
69893cff
RGS
2424
2425=head4 C<f> - switch files
2426
2427=cut
2428
826b9a2e 2429 if (($file) = $cmd =~ /\Af\b\s*(.*)/) {
e22ea7cc 2430 $file =~ s/\s+$//;
69893cff
RGS
2431
2432 # help for no arguments (old-style was return from sub).
e22ea7cc
RF
2433 if ( !$file ) {
2434 print $OUT
2435 "The old f command is now the r command.\n"; # hint
2436 print $OUT "The new f command switches filenames.\n";
2437 next CMD;
2438 } ## end if (!$file)
69893cff
RGS
2439
2440 # if not in magic file list, try a close match.
e22ea7cc
RF
2441 if ( !defined $main::{ '_<' . $file } ) {
2442 if ( ($try) = grep( m#^_<.*$file#, keys %main:: ) ) {
2443 {
2444 $try = substr( $try, 2 );
1f874cb6 2445 print $OUT "Choosing $try matching '$file':\n";
e22ea7cc
RF
2446 $file = $try;
2447 }
2448 } ## end if (($try) = grep(m#^_<.*$file#...
2449 } ## end if (!defined $main::{ ...
69893cff
RGS
2450
2451 # If not successfully switched now, we failed.
e22ea7cc 2452 if ( !defined $main::{ '_<' . $file } ) {
1f874cb6 2453 print $OUT "No file matching '$file' is loaded.\n";
e22ea7cc
RF
2454 next CMD;
2455 }
69893cff 2456
e22ea7cc
RF
2457 # We switched, so switch the debugger internals around.
2458 elsif ( $file ne $filename ) {
2459 *dbline = $main::{ '_<' . $file };
2460 $max = $#dbline;
2461 $filename = $file;
2462 $start = 1;
2463 $cmd = "l";
2464 } ## end elsif ($file ne $filename)
2465
2466 # We didn't switch; say we didn't.
2467 else {
2468 print $OUT "Already in $file.\n";
2469 next CMD;
2470 }
826b9a2e 2471 }
69893cff
RGS
2472
2473=head4 C<.> - return to last-executed line.
2474
2475We set C<$incr> to -1 to indicate that the debugger shouldn't move ahead,
2476and then we look up the line in the magical C<%dbline> hash.
2477
2478=cut
2479
2480 # . command.
826b9a2e 2481 if ($cmd eq '.') {
e22ea7cc 2482 $incr = -1; # stay at current line
69893cff
RGS
2483
2484 # Reset everything to the old location.
e22ea7cc
RF
2485 $start = $line;
2486 $filename = $filename_ini;
2487 *dbline = $main::{ '_<' . $filename };
2488 $max = $#dbline;
69893cff
RGS
2489
2490 # Now where are we?
e22ea7cc
RF
2491 print_lineinfo($position);
2492 next CMD;
826b9a2e 2493 }
69893cff
RGS
2494
2495=head4 C<-> - back one window
2496
2497We change C<$start> to be one window back; if we go back past the first line,
2498we set it to be the first line. We ser C<$incr> to put us back at the
2499currently-executing line, and then put a C<l $start +> (list one window from
2500C<$start>) in C<$cmd> to be executed later.
2501
2502=cut
2503
2504 # - - back a window.
826b9a2e 2505 if ($cmd eq '-') {
e22ea7cc 2506
69893cff 2507 # back up by a window; go to 1 if back too far.
e22ea7cc
RF
2508 $start -= $incr + $window + 1;
2509 $start = 1 if $start <= 0;
2510 $incr = $window - 1;
69893cff
RGS
2511
2512 # Generate and execute a "l +" command (handled below).
e22ea7cc 2513 $cmd = 'l ' . ($start) . '+';
826b9a2e 2514 }
69893cff
RGS
2515
2516=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>, {, {{>
2517
2518In Perl 5.8.0, a realignment of the commands was done to fix up a number of
2519problems, most notably that the default case of several commands destroying
2520the user's work in setting watchpoints, actions, etc. We wanted, however, to
2521retain the old commands for those who were used to using them or who preferred
2522them. At this point, we check for the new commands and call C<cmd_wrapper> to
2523deal with them instead of processing them in-line.
2524
2525=cut
2526
2527 # All of these commands were remapped in perl 5.8.0;
e22ea7cc 2528 # we send them off to the secondary dispatcher (see below).
826b9a2e
SF
2529 if (my ($cmd_letter, $my_arg) = $cmd =~ /\A([aAbBeEhilLMoOPvwW]\b|[<>\{]{1,2})\s*(.*)/so) {
2530 &cmd_wrapper( $cmd_letter, $my_arg, $line );
e22ea7cc 2531 next CMD;
826b9a2e 2532 }
69893cff
RGS
2533
2534=head4 C<y> - List lexicals in higher scope
2535
826b9a2e 2536Uses C<PadWalker> to find the lexicals supplied as arguments in a scope
69893cff
RGS
2537above the current one and then displays then using C<dumpvar.pl>.
2538
2539=cut
2540
826b9a2e
SF
2541 if (my ($match_level, $match_vars)
2542 = $cmd =~ /^y(?:\s+(\d*)\s*(.*))?$/) {
69893cff
RGS
2543
2544 # See if we've got the necessary support.
2545 eval { require PadWalker; PadWalker->VERSION(0.08) }
2546 or &warn(
2547 $@ =~ /locate/
2548 ? "PadWalker module not found - please install\n"
2549 : $@
2550 )
2551 and next CMD;
2552
2553 # Load up dumpvar if we don't have it. If we can, that is.
e81465be 2554 do 'dumpvar.pl' || die $@ unless defined &main::dumpvar;
69893cff
RGS
2555 defined &main::dumpvar
2556 or print $OUT "dumpvar.pl not available.\n"
2557 and next CMD;
2558
2559 # Got all the modules we need. Find them and print them.
826b9a2e 2560 my @vars = split( ' ', $match_vars || '' );
69893cff
RGS
2561
2562 # Find the pad.
826b9a2e 2563 my $h = eval { PadWalker::peek_my( ( $match_level || 0 ) + 1 ) };
69893cff
RGS
2564
2565 # Oops. Can't find it.
2566 $@ and $@ =~ s/ at .*//, &warn($@), next CMD;
2567
2568 # Show the desired vars with dumplex().
2569 my $savout = select($OUT);
2570
2571 # Have dumplex dump the lexicals.
e22ea7cc 2572 dumpvar::dumplex( $_, $h->{$_},
69893cff 2573 defined $option{dumpDepth} ? $option{dumpDepth} : -1,
e22ea7cc
RF
2574 @vars )
2575 for sort keys %$h;
69893cff
RGS
2576 select($savout);
2577 next CMD;
826b9a2e 2578 }
69893cff
RGS
2579
2580=head3 COMMANDS NOT WORKING AFTER PROGRAM ENDS
2581
2582All of the commands below this point don't work after the program being
2583debugged has ended. All of them check to see if the program has ended; this
2584allows the commands to be relocated without worrying about a 'line of
2585demarcation' above which commands can be entered anytime, and below which
2586they can't.
2587
2588=head4 C<n> - single step, but don't trace down into subs
2589
2590Done by setting C<$single> to 2, which forces subs to execute straight through
be9a9b1d 2591when entered (see C<DB::sub>). We also save the C<n> command in C<$laststep>,
826b9a2e 2592so a null command knows what to re-execute.
69893cff
RGS
2593
2594=cut
2595
e22ea7cc 2596 # n - next
826b9a2e 2597 if ($cmd eq 'n') {
69893cff 2598 end_report(), next CMD if $finished and $level <= 1;
e22ea7cc 2599
69893cff
RGS
2600 # Single step, but don't enter subs.
2601 $single = 2;
e22ea7cc 2602
69893cff 2603 # Save for empty command (repeat last).
e22ea7cc
RF
2604 $laststep = $cmd;
2605 last CMD;
826b9a2e 2606 }
69893cff
RGS
2607
2608=head4 C<s> - single-step, entering subs
2609
826b9a2e 2610Sets C<$single> to 1, which causes C<DB::sub> to continue tracing inside
69893cff
RGS
2611subs. Also saves C<s> as C<$lastcmd>.
2612
2613=cut
2614
2615 # s - single step.
826b9a2e 2616 if ($cmd eq 's') {
e22ea7cc 2617
69893cff
RGS
2618 # Get out and restart the command loop if program
2619 # has finished.
e22ea7cc
RF
2620 end_report(), next CMD if $finished and $level <= 1;
2621
69893cff 2622 # Single step should enter subs.
e22ea7cc
RF
2623 $single = 1;
2624
69893cff 2625 # Save for empty command (repeat last).
e22ea7cc
RF
2626 $laststep = $cmd;
2627 last CMD;
826b9a2e 2628 }
69893cff
RGS
2629
2630=head4 C<c> - run continuously, setting an optional breakpoint
2631
2632Most of the code for this command is taken up with locating the optional
2633breakpoint, which is either a subroutine name or a line number. We set
2634the appropriate one-time-break in C<@dbline> and then turn off single-stepping
2635in this and all call levels above this one.
2636
2637=cut
2638
2639 # c - start continuous execution.
ef18ae63 2640 if (($i) = $cmd =~ m#\Ac\b\s*([\w:]*)\s*\z#) {
e22ea7cc 2641
69893cff
RGS
2642 # Hey, show's over. The debugged program finished
2643 # executing already.
2644 end_report(), next CMD if $finished and $level <= 1;
2645
2646 # Capture the place to put a one-time break.
ef18ae63 2647 $subname = $i;
69893cff 2648
e22ea7cc
RF
2649 # Probably not needed, since we finish an interactive
2650 # sub-session anyway...
2651 # local $filename = $filename;
2652 # local *dbline = *dbline; # XXX Would this work?!
69893cff
RGS
2653 #
2654 # The above question wonders if localizing the alias
2655 # to the magic array works or not. Since it's commented
2656 # out, we'll just leave that to speculation for now.
2657
2658 # If the "subname" isn't all digits, we'll assume it
2659 # is a subroutine name, and try to find it.
e22ea7cc
RF
2660 if ( $subname =~ /\D/ ) { # subroutine name
2661 # Qualify it to the current package unless it's
2662 # already qualified.
69893cff
RGS
2663 $subname = $package . "::" . $subname
2664 unless $subname =~ /::/;
e22ea7cc 2665
69893cff
RGS
2666 # find_sub will return "file:line_number" corresponding
2667 # to where the subroutine is defined; we call find_sub,
e22ea7cc 2668 # break up the return value, and assign it in one
69893cff 2669 # operation.
e22ea7cc 2670 ( $file, $i ) = ( find_sub($subname) =~ /^(.*):(.*)$/ );
69893cff
RGS
2671
2672 # Force the line number to be numeric.
e22ea7cc 2673 $i += 0;
69893cff
RGS
2674
2675 # If we got a line number, we found the sub.
e22ea7cc
RF
2676 if ($i) {
2677
69893cff
RGS
2678 # Switch all the debugger's internals around so
2679 # we're actually working with that file.
e22ea7cc
RF
2680 $filename = $file;
2681 *dbline = $main::{ '_<' . $filename };
2682
69893cff 2683 # Mark that there's a breakpoint in this file.
e22ea7cc
RF
2684 $had_breakpoints{$filename} |= 1;
2685
69893cff
RGS
2686 # Scan forward to the first executable line
2687 # after the 'sub whatever' line.
e22ea7cc
RF
2688 $max = $#dbline;
2689 ++$i while $dbline[$i] == 0 && $i < $max;
2690 } ## end if ($i)
69893cff
RGS
2691
2692 # We didn't find a sub by that name.
e22ea7cc
RF
2693 else {
2694 print $OUT "Subroutine $subname not found.\n";
2695 next CMD;
2696 }
2697 } ## end if ($subname =~ /\D/)
69893cff
RGS
2698
2699 # At this point, either the subname was all digits (an
2700 # absolute line-break request) or we've scanned through
2701 # the code following the definition of the sub, looking
2702 # for an executable, which we may or may not have found.
2703 #
2704 # If $i (which we set $subname from) is non-zero, we
e22ea7cc
RF
2705 # got a request to break at some line somewhere. On
2706 # one hand, if there wasn't any real subroutine name
2707 # involved, this will be a request to break in the current
2708 # file at the specified line, so we have to check to make
69893cff
RGS
2709 # sure that the line specified really is breakable.
2710 #
2711 # On the other hand, if there was a subname supplied, the
3c4b39be 2712 # preceding block has moved us to the proper file and
69893cff
RGS
2713 # location within that file, and then scanned forward
2714 # looking for the next executable line. We have to make
2715 # sure that one was found.
2716 #
2717 # On the gripping hand, we can't do anything unless the
2718 # current value of $i points to a valid breakable line.
2719 # Check that.
e22ea7cc
RF
2720 if ($i) {
2721
69893cff 2722 # Breakable?
e22ea7cc
RF
2723 if ( $dbline[$i] == 0 ) {
2724 print $OUT "Line $i not breakable.\n";
2725 next CMD;
2726 }
2727
69893cff 2728 # Yes. Set up the one-time-break sigil.
e22ea7cc 2729 $dbline{$i} =~ s/($|\0)/;9$1/; # add one-time-only b.p.
5d5d9ea3 2730 _enable_breakpoint_temp_enabled_status($filename, $i);
e22ea7cc 2731 } ## end if ($i)
69893cff
RGS
2732
2733 # Turn off stack tracing from here up.
2c247e84
SF
2734 for my $i (0 .. $stack_depth) {
2735 $stack[ $i ] &= ~1;
e22ea7cc
RF
2736 }
2737 last CMD;
ef18ae63 2738 }
69893cff
RGS
2739
2740=head4 C<r> - return from a subroutine
2741
2742For C<r> to work properly, the debugger has to stop execution again
2743immediately after the return is executed. This is done by forcing
2744single-stepping to be on in the call level above the current one. If
2745we are printing return values when a C<r> is executed, set C<$doret>
2746appropriately, and force us out of the command loop.
2747
2748=cut
2749
2750 # r - return from the current subroutine.
ef18ae63 2751 if ($cmd eq 'r') {
e22ea7cc 2752
98dc9551 2753 # Can't do anything if the program's over.
e22ea7cc
RF
2754 end_report(), next CMD if $finished and $level <= 1;
2755
69893cff 2756 # Turn on stack trace.
e22ea7cc
RF
2757 $stack[$stack_depth] |= 1;
2758
69893cff 2759 # Print return value unless the stack is empty.
e22ea7cc
RF
2760 $doret = $option{PrintRet} ? $stack_depth - 1 : -2;
2761 last CMD;
ef18ae63 2762 }
69893cff 2763
69893cff
RGS
2764=head4 C<T> - stack trace
2765
2766Just calls C<DB::print_trace>.
2767
2768=cut
2769
ef18ae63 2770 if ($cmd eq 'T') {
e22ea7cc
RF
2771 print_trace( $OUT, 1 ); # skip DB
2772 next CMD;
ef18ae63 2773 }
69893cff
RGS
2774
2775=head4 C<w> - List window around current line.
2776
2777Just calls C<DB::cmd_w>.
2778
2779=cut
2780
ef18ae63
SF
2781 if (my ($arg) = $cmd =~ /\Aw\b\s*(.*)/s) {
2782 &cmd_w( 'w', $arg );
2783 next CMD;
2784 }
69893cff
RGS
2785
2786=head4 C<W> - watch-expression processing.
2787
b570d64b 2788Just calls C<DB::cmd_W>.
69893cff
RGS
2789
2790=cut
2791
ef18ae63
SF
2792 if (my ($arg) = $cmd =~ /\AW\b\s*(.*)/s) {
2793 &cmd_W( 'W', $arg );
2794 next CMD;
2795 }
69893cff
RGS
2796
2797=head4 C</> - search forward for a string in the source
2798
ef18ae63 2799We take the argument and treat it as a pattern. If it turns out to be a
69893cff 2800bad one, we return the error we got from trying to C<eval> it and exit.
ef18ae63 2801If not, we create some code to do the search and C<eval> it so it can't
69893cff
RGS
2802mess us up.
2803
2804=cut
2805
ef18ae63
SF
2806 # The pattern as a string.
2807 use vars qw($inpat);
69893cff 2808
ef18ae63 2809 if (($inpat) = $cmd =~ m#\A/(.*)\z#) {
69893cff
RGS
2810
2811 # Remove the final slash.
e22ea7cc 2812 $inpat =~ s:([^\\])/$:$1:;
69893cff
RGS
2813
2814 # If the pattern isn't null ...
e22ea7cc 2815 if ( $inpat ne "" ) {
69893cff
RGS
2816
2817 # Turn of warn and die procesing for a bit.
e22ea7cc
RF
2818 local $SIG{__DIE__};
2819 local $SIG{__WARN__};
69893cff
RGS
2820
2821 # Create the pattern.
e22ea7cc
RF
2822 eval '$inpat =~ m' . "\a$inpat\a";
2823 if ( $@ ne "" ) {
2824
69893cff 2825 # Oops. Bad pattern. No biscuit.
e22ea7cc 2826 # Print the eval error and go back for more
69893cff 2827 # commands.
e22ea7cc
RF
2828 print $OUT "$@";
2829 next CMD;
2830 }
2831 $pat = $inpat;
2832 } ## end if ($inpat ne "")
69893cff
RGS
2833
2834 # Set up to stop on wrap-around.
e22ea7cc 2835 $end = $start;
69893cff
RGS
2836
2837 # Don't move off the current line.
e22ea7cc 2838 $incr = -1;
69893cff
RGS
2839
2840 # Done in eval so nothing breaks if the pattern
2841 # does something weird.
e22ea7cc
RF
2842 eval '
2843 for (;;) {
69893cff 2844 # Move ahead one line.
e22ea7cc 2845 ++$start;
69893cff
RGS
2846
2847 # Wrap if we pass the last line.
e22ea7cc 2848 $start = 1 if ($start > $max);
69893cff
RGS
2849
2850 # Stop if we have gotten back to this line again,
e22ea7cc 2851 last if ($start == $end);
69893cff
RGS
2852
2853 # A hit! (Note, though, that we are doing
2854 # case-insensitive matching. Maybe a qr//
2855 # expression would be better, so the user could
2856 # do case-sensitive matching if desired.
e22ea7cc
RF
2857 if ($dbline[$start] =~ m' . "\a$pat\a" . 'i) {
2858 if ($slave_editor) {
69893cff 2859 # Handle proper escaping in the slave.
e22ea7cc 2860 print $OUT "\032\032$filename:$start:0\n";
b570d64b 2861 }
e22ea7cc 2862 else {
69893cff 2863 # Just print the line normally.
e22ea7cc
RF
2864 print $OUT "$start:\t",$dbline[$start],"\n";
2865 }
69893cff 2866 # And quit since we found something.
e22ea7cc
RF
2867 last;
2868 }
2869 } ';
2870
69893cff 2871 # If we wrapped, there never was a match.
e22ea7cc
RF
2872 print $OUT "/$pat/: not found\n" if ( $start == $end );
2873 next CMD;
ef18ae63 2874 }
69893cff
RGS
2875
2876=head4 C<?> - search backward for a string in the source
2877
2878Same as for C</>, except the loop runs backwards.
2879
2880=cut
2881
2882 # ? - backward pattern search.
ef18ae63 2883 if (my ($inpat) = $cmd =~ m#\A\?(.*)\z#) {
69893cff
RGS
2884
2885 # Get the pattern, remove trailing question mark.
e22ea7cc 2886 $inpat =~ s:([^\\])\?$:$1:;
69893cff
RGS
2887
2888 # If we've got one ...
e22ea7cc 2889 if ( $inpat ne "" ) {
69893cff
RGS
2890
2891 # Turn off die & warn handlers.
e22ea7cc
RF
2892 local $SIG{__DIE__};
2893 local $SIG{__WARN__};
2894 eval '$inpat =~ m' . "\a$inpat\a";
2895
2896 if ( $@ ne "" ) {
2897
69893cff 2898 # Ouch. Not good. Print the error.
e22ea7cc
RF
2899 print $OUT $@;
2900 next CMD;
2901 }
2902 $pat = $inpat;
69893cff 2903 } ## end if ($inpat ne "")
e22ea7cc 2904
69893cff 2905 # Where we are now is where to stop after wraparound.
e22ea7cc 2906 $end = $start;
69893cff
RGS
2907
2908 # Don't move away from this line.
e22ea7cc 2909 $incr = -1;
69893cff
RGS
2910
2911 # Search inside the eval to prevent pattern badness
2912 # from killing us.
e22ea7cc
RF
2913 eval '
2914 for (;;) {
69893cff 2915 # Back up a line.
e22ea7cc 2916 --$start;
69893cff
RGS
2917
2918 # Wrap if we pass the first line.
e22ea7cc
RF
2919
2920 $start = $max if ($start <= 0);
69893cff
RGS
2921
2922 # Quit if we get back where we started,
e22ea7cc 2923 last if ($start == $end);
69893cff
RGS
2924
2925 # Match?
e22ea7cc
RF
2926 if ($dbline[$start] =~ m' . "\a$pat\a" . 'i) {
2927 if ($slave_editor) {
69893cff 2928 # Yep, follow slave editor requirements.
e22ea7cc 2929 print $OUT "\032\032$filename:$start:0\n";
b570d64b 2930 }
e22ea7cc 2931 else {
69893cff 2932 # Yep, just print normally.
e22ea7cc
RF
2933 print $OUT "$start:\t",$dbline[$start],"\n";
2934 }
69893cff
RGS
2935
2936 # Found, so done.
e22ea7cc
RF
2937 last;
2938 }
2939 } ';
2940
2941 # Say we failed if the loop never found anything,
2942 print $OUT "?$pat?: not found\n" if ( $start == $end );
2943 next CMD;
ef18ae63 2944 }
69893cff
RGS
2945
2946=head4 C<$rc> - Recall command
2947
2948Manages the commands in C<@hist> (which is created if C<Term::ReadLine> reports
2949that the terminal supports history). It find the the command required, puts it
2950into C<$cmd>, and redoes the loop to execute it.
2951
2952=cut
2953
e22ea7cc 2954 # $rc - recall command.
ef18ae63 2955 if (my ($minus, $arg) = $cmd =~ m#\A$rc+\s*(-)?(\d+)?\z#) {
69893cff
RGS
2956
2957 # No arguments, take one thing off history.
e22ea7cc 2958 pop(@hist) if length($cmd) > 1;
69893cff 2959
e22ea7cc 2960 # Relative (- found)?
69893cff 2961 # Y - index back from most recent (by 1 if bare minus)
e22ea7cc 2962 # N - go to that particular command slot or the last
69893cff 2963 # thing if nothing following.
ef18ae63 2964 $i = $minus ? ( $#hist - ( $arg || 1 ) ) : ( $arg || $#hist );
69893cff
RGS
2965
2966 # Pick out the command desired.
e22ea7cc 2967 $cmd = $hist[$i];
69893cff
RGS
2968
2969 # Print the command to be executed and restart the loop
2970 # with that command in the buffer.
e22ea7cc
RF
2971 print $OUT $cmd, "\n";
2972 redo CMD;
ef18ae63 2973 }
69893cff
RGS
2974
2975=head4 C<$sh$sh> - C<system()> command
2976
2977Calls the C<DB::system()> to handle the command. This keeps the C<STDIN> and
2978C<STDOUT> from getting messed up.
2979
2980=cut
2981
2982 # $sh$sh - run a shell command (if it's all ASCII).
2983 # Can't run shell commands with Unicode in the debugger, hmm.
ef18ae63 2984 if (my ($arg) = $cmd =~ m#\A$sh$sh\s*(.*)#ms) {
e22ea7cc 2985
69893cff 2986 # System it.
ef18ae63 2987 &system($arg);
e22ea7cc 2988 next CMD;
ef18ae63 2989 }
69893cff
RGS
2990
2991=head4 C<$rc I<pattern> $rc> - Search command history
2992
2993Another command to manipulate C<@hist>: this one searches it with a pattern.
be9a9b1d 2994If a command is found, it is placed in C<$cmd> and executed via C<redo>.
69893cff
RGS
2995
2996=cut
2997
e22ea7cc 2998 # $rc pattern $rc - find a command in the history.
ef18ae63 2999 if (my ($arg) = $cmd =~ /\A$rc([^$rc].*)\z/) {
e22ea7cc 3000
69893cff 3001 # Create the pattern to use.
ef18ae63 3002 $pat = "^$arg";
69893cff
RGS
3003
3004 # Toss off last entry if length is >1 (and it always is).
e22ea7cc 3005 pop(@hist) if length($cmd) > 1;
69893cff
RGS
3006
3007 # Look backward through the history.
72d7d80d 3008 for ( $i = $#hist ; $i ; --$i ) {
69893cff 3009 # Stop if we find it.
e22ea7cc
RF
3010 last if $hist[$i] =~ /$pat/;
3011 }
3012
3013 if ( !$i ) {
69893cff 3014
69893cff 3015 # Never found it.
e22ea7cc
RF
3016 print $OUT "No such command!\n\n";
3017 next CMD;
3018 }
69893cff
RGS
3019
3020 # Found it. Put it in the buffer, print it, and process it.
e22ea7cc
RF
3021 $cmd = $hist[$i];
3022 print $OUT $cmd, "\n";
3023 redo CMD;
ef18ae63 3024 }
69893cff 3025
ef18ae63 3026=head4 C<$sh> - Invoke a shell
69893cff
RGS
3027
3028Uses C<DB::system> to invoke a shell.
3029
3030=cut
3031
3032 # $sh - start a shell.
ef18ae63 3033 if ($cmd =~ /\A$sh\z/) {
e22ea7cc 3034
69893cff
RGS
3035 # Run the user's shell. If none defined, run Bourne.
3036 # We resume execution when the shell terminates.
e22ea7cc
RF
3037 &system( $ENV{SHELL} || "/bin/sh" );
3038 next CMD;
ef18ae63 3039 }
69893cff
RGS
3040
3041=head4 C<$sh I<command>> - Force execution of a command in a shell
3042
3043Like the above, but the command is passed to the shell. Again, we use
3044C<DB::system> to avoid problems with C<STDIN> and C<STDOUT>.
3045
3046=cut
3047
3048 # $sh command - start a shell and run a command in it.
ef18ae63 3049 if (my ($arg) = $cmd =~ m#\A$sh\s*(.*)#ms) {
e22ea7cc
RF
3050
3051 # XXX: using csh or tcsh destroys sigint retvals!
3052 #&system($1); # use this instead
69893cff
RGS
3053
3054 # use the user's shell, or Bourne if none defined.
ef18ae63 3055 &system( $ENV{SHELL} || "/bin/sh", "-c", $arg );
e22ea7cc 3056 next CMD;
ef18ae63 3057 }
69893cff
RGS
3058
3059=head4 C<H> - display commands in history
3060
3061Prints the contents of C<@hist> (if any).
3062
3063=cut
3064
ef18ae63 3065 if ($cmd =~ /\AH\b\s*\*/) {
7fddc82f
RF
3066 @hist = @truehist = ();
3067 print $OUT "History cleansed\n";
3068 next CMD;
ef18ae63 3069 }
e22ea7cc 3070
ef18ae63
SF
3071 if (my ($num)
3072 = $cmd =~ /\AH\b\s*(?:-(\d+))?/) {
e22ea7cc
RF
3073
3074 # Anything other than negative numbers is ignored by
69893cff 3075 # the (incorrect) pattern, so this test does nothing.
ef18ae63 3076 $end = $num ? ( $#hist - $num ) : 0;
69893cff
RGS
3077
3078 # Set to the minimum if less than zero.
e22ea7cc 3079 $hist = 0 if $hist < 0;
69893cff 3080
e22ea7cc 3081 # Start at the end of the array.
69893cff
RGS
3082 # Stay in while we're still above the ending value.
3083 # Tick back by one each time around the loop.
72d7d80d 3084 for ( $i = $#hist ; $i > $end ; $i-- ) {
69893cff
RGS
3085
3086 # Print the command unless it has no arguments.
e22ea7cc
RF
3087 print $OUT "$i: ", $hist[$i], "\n"
3088 unless $hist[$i] =~ /^.?$/;
3089 }
3090 next CMD;
ef18ae63 3091 }
69893cff
RGS
3092
3093=head4 C<man, doc, perldoc> - look up documentation
3094
3095Just calls C<runman()> to print the appropriate document.
3096
3097=cut
3098
e22ea7cc 3099 # man, perldoc, doc - show manual pages.
ef18ae63
SF
3100 if (my ($man_page)
3101 = $cmd =~ /\A(?:man|(?:perl)?doc)\b(?:\s+([^(]*))?\z/) {
3102 runman($man_page);
e22ea7cc 3103 next CMD;
ef18ae63 3104 }
69893cff
RGS
3105
3106=head4 C<p> - print
3107
3108Builds a C<print EXPR> expression in the C<$cmd>; this will get executed at
3109the bottom of the loop.
3110
3111=cut
3112
ef18ae63 3113 my $print_cmd = 'print {$DB::OUT} ';
69893cff 3114 # p - print (no args): print $_.
ef18ae63
SF
3115 if ($cmd eq 'p') {
3116 $cmd = $print_cmd . '$_';
3117 }
69893cff
RGS
3118
3119 # p - print the given expression.
ef18ae63 3120 $cmd =~ s/\Ap\b/$print_cmd /;
69893cff
RGS
3121
3122=head4 C<=> - define command alias
3123
3124Manipulates C<%alias> to add or list command aliases.
3125
3126=cut
3127
e22ea7cc 3128 # = - set up a command alias.
ef18ae63 3129 if ($cmd =~ s/\A=\s*//) {
e22ea7cc
RF
3130 my @keys;
3131 if ( length $cmd == 0 ) {
3132
69893cff 3133 # No args, get current aliases.
e22ea7cc
RF
3134 @keys = sort keys %alias;
3135 }
3136 elsif ( my ( $k, $v ) = ( $cmd =~ /^(\S+)\s+(\S.*)/ ) ) {
3137
69893cff
RGS
3138 # Creating a new alias. $k is alias name, $v is
3139 # alias value.
3140
e22ea7cc
RF
3141 # can't use $_ or kill //g state
3142 for my $x ( $k, $v ) {
3143
3144 # Escape "alarm" characters.
3145 $x =~ s/\a/\\a/g;
3146 }
69893cff
RGS
3147
3148 # Substitute key for value, using alarm chars
e22ea7cc 3149 # as separators (which is why we escaped them in
69893cff 3150 # the command).
e22ea7cc 3151 $alias{$k} = "s\a$k\a$v\a";
69893cff
RGS
3152
3153 # Turn off standard warn and die behavior.
e22ea7cc
RF
3154 local $SIG{__DIE__};
3155 local $SIG{__WARN__};
69893cff
RGS
3156
3157 # Is it valid Perl?
e22ea7cc
RF
3158 unless ( eval "sub { s\a$k\a$v\a }; 1" ) {
3159
69893cff 3160 # Nope. Bad alias. Say so and get out.
e22ea7cc
RF
3161 print $OUT "Can't alias $k to $v: $@\n";
3162 delete $alias{$k};
3163 next CMD;
3164 }
3165
69893cff 3166 # We'll only list the new one.
e22ea7cc 3167 @keys = ($k);
69893cff
RGS
3168 } ## end elsif (my ($k, $v) = ($cmd...
3169
3170 # The argument is the alias to list.
e22ea7cc
RF
3171 else {
3172 @keys = ($cmd);
3173 }
69893cff
RGS
3174
3175 # List aliases.
e22ea7cc
RF
3176 for my $k (@keys) {
3177
98dc9551 3178 # Messy metaquoting: Trim the substitution code off.
69893cff
RGS
3179 # We use control-G as the delimiter because it's not
3180 # likely to appear in the alias.
e22ea7cc
RF
3181 if ( ( my $v = $alias{$k} ) =~ s\as\a$k\a(.*)\a$\a1\a ) {
3182
69893cff 3183 # Print the alias.
e22ea7cc
RF
3184 print $OUT "$k\t= $1\n";
3185 }
3186 elsif ( defined $alias{$k} ) {
3187
69893cff 3188 # Couldn't trim it off; just print the alias code.
e22ea7cc
RF
3189 print $OUT "$k\t$alias{$k}\n";
3190 }
3191 else {
3192
69893cff 3193 # No such, dude.
e22ea7cc
RF
3194 print "No alias for $k\n";
3195 }
69893cff 3196 } ## end for my $k (@keys)
e22ea7cc 3197 next CMD;
ef18ae63 3198 }
69893cff
RGS
3199
3200=head4 C<source> - read commands from a file.
3201
3202Opens a lexical filehandle and stacks it on C<@cmdfhs>; C<DB::readline> will
3203pick it up.
3204
3205=cut
3206
e22ea7cc 3207 # source - read commands from a file (or pipe!) and execute.
ef18ae63
SF
3208 if (my ($sourced_fn) = $cmd =~ /\Asource\s+(.*\S)/) {
3209 if ( open my $fh, $sourced_fn ) {
e22ea7cc 3210
69893cff 3211 # Opened OK; stick it in the list of file handles.
e22ea7cc
RF
3212 push @cmdfhs, $fh;
3213 }
3214 else {
3215
3216 # Couldn't open it.
ef18ae63 3217 &warn("Can't execute '$sourced_fn': $!\n");
e22ea7cc
RF
3218 }
3219 next CMD;
ef18ae63 3220 }
69893cff 3221
ef18ae63
SF
3222 if (my ($which_cmd, $position)
3223 = $cmd =~ /^(enable|disable)\s+(\S+)\s*$/) {
e09195af
SF
3224
3225 my ($fn, $line_num);
3226 if ($position =~ m{\A\d+\z})
3227 {
3228 $fn = $filename;
3229 $line_num = $position;
3230 }
ef18ae63
SF
3231 elsif (my ($new_fn, $new_line_num)
3232 = $position =~ m{\A(.*):(\d+)\z}) {
3233 ($fn, $line_num) = ($new_fn, $new_line_num);
e09195af
SF
3234 }
3235 else
3236 {
3237 &warn("Wrong spec for enable/disable argument.\n");
3238 }
3239
3240 if (defined($fn)) {
3241 if (_has_breakpoint_data_ref($fn, $line_num)) {
3242 _set_breakpoint_enabled_status($fn, $line_num,
ef18ae63 3243 ($which_cmd eq 'enable' ? 1 : '')
e09195af
SF
3244 );
3245 }
3246 else {
3247 &warn("No breakpoint set at ${fn}:${line_num}\n");
3248 }
3249 }
3250
3251 next CMD;
ef18ae63 3252 }
e09195af 3253
69893cff
RGS
3254=head4 C<save> - send current history to a file
3255
3256Takes the complete history, (not the shrunken version you see with C<H>),
3257and saves it to the given filename, so it can be replayed using C<source>.
3258
3259Note that all C<^(save|source)>'s are commented out with a view to minimise recursion.
3260
3261=cut
3262
3263 # save source - write commands to a file for later use
ef18ae63
SF
3264 if (my ($new_fn) = $cmd =~ /\Asave\s*(.*)\z/) {
3265 my $filename = $new_fn || '.perl5dbrc'; # default?
3266 if ( open my $fh, '>', $filename ) {
e22ea7cc
RF
3267
3268 # chomp to remove extraneous newlines from source'd files
3269 chomp( my @truelist =
3270 map { m/^\s*(save|source)/ ? "#$_" : $_ }
3271 @truehist );
3272 print $fh join( "\n", @truelist );
69893cff 3273 print "commands saved in $file\n";
e22ea7cc
RF
3274 }
3275 else {
ef18ae63 3276 &warn("Can't save debugger commands in '$new_fn': $!\n");
69893cff
RGS
3277 }
3278 next CMD;
ef18ae63 3279 }
69893cff 3280
7fddc82f
RF
3281=head4 C<R> - restart
3282
ef18ae63 3283Restart the debugger session.
7fddc82f
RF
3284
3285=head4 C<rerun> - rerun the current session
3286
3287Return to any given position in the B<true>-history list
3288
3289=cut
3290
3291 # R - restart execution.
3292 # rerun - controlled restart execution.
ff41e38d
SF
3293 if (my ($cmd_cmd, $cmd_params) =
3294 $cmd =~ /\A((?:R)|(?:rerun\s*(.*)))\z/) {
3295 my @args = ($cmd_cmd eq 'R' ? restart() : rerun($cmd_params));
7fddc82f 3296
ca28b541
AP
3297 # Close all non-system fds for a clean restart. A more
3298 # correct method would be to close all fds that were not
3299 # open when the process started, but this seems to be
3300 # hard. See "debugger 'R'estart and open database
3301 # connections" on p5p.
3302
47d3bbda 3303 my $max_fd = 1024; # default if POSIX can't be loaded
ca28b541 3304 if (eval { require POSIX }) {
5332cc68 3305 eval { $max_fd = POSIX::sysconf(POSIX::_SC_OPEN_MAX()) };
ca28b541
AP
3306 }
3307
3308 if (defined $max_fd) {
3309 foreach ($^F+1 .. $max_fd-1) {
3310 next unless open FD_TO_CLOSE, "<&=$_";
3311 close(FD_TO_CLOSE);
3312 }
3313 }
3314
7fddc82f
RF
3315 # And run Perl again. We use exec() to keep the
3316 # PID stable (and that way $ini_pids is still valid).
3317 exec(@args) || print $OUT "exec failed: $!\n";
3318
3319 last CMD;
ff41e38d 3320 }
7fddc82f 3321
69893cff
RGS
3322=head4 C<|, ||> - pipe output through the pager.
3323
be9a9b1d 3324For C<|>, we save C<OUT> (the debugger's output filehandle) and C<STDOUT>
69893cff
RGS
3325(the program's standard output). For C<||>, we only save C<OUT>. We open a
3326pipe to the pager (restoring the output filehandles if this fails). If this
b570d64b 3327is the C<|> command, we also set up a C<SIGPIPE> handler which will simply
69893cff
RGS
3328set C<$signal>, sending us back into the debugger.
3329
3330We then trim off the pipe symbols and C<redo> the command loop at the
3331C<PIPE> label, causing us to evaluate the command in C<$cmd> without
3332reading another.
3333
3334=cut
3335
3336 # || - run command in the pager, with output to DB::OUT.
ff41e38d 3337 if ($cmd =~ m#\A\|\|?\s*[^|]#) {
e22ea7cc
RF
3338 if ( $pager =~ /^\|/ ) {
3339
69893cff 3340 # Default pager is into a pipe. Redirect I/O.
e22ea7cc
RF
3341 open( SAVEOUT, ">&STDOUT" )
3342 || &warn("Can't save STDOUT");
3343 open( STDOUT, ">&OUT" )
3344 || &warn("Can't redirect STDOUT");
69893cff 3345 } ## end if ($pager =~ /^\|/)
e22ea7cc
RF
3346 else {
3347
69893cff 3348 # Not into a pipe. STDOUT is safe.
e22ea7cc
RF
3349 open( SAVEOUT, ">&OUT" ) || &warn("Can't save DB::OUT");
3350 }
69893cff
RGS
3351
3352 # Fix up environment to record we have less if so.
e22ea7cc
RF
3353 fix_less();
3354
3355 unless ( $piped = open( OUT, $pager ) ) {
69893cff 3356
69893cff 3357 # Couldn't open pipe to pager.
1f874cb6 3358 &warn("Can't pipe output to '$pager'");
e22ea7cc
RF
3359 if ( $pager =~ /^\|/ ) {
3360
69893cff 3361 # Redirect I/O back again.
e22ea7cc
RF
3362 open( OUT, ">&STDOUT" ) # XXX: lost message
3363 || &warn("Can't restore DB::OUT");
3364 open( STDOUT, ">&SAVEOUT" )
3365 || &warn("Can't restore STDOUT");
3366 close(SAVEOUT);
69893cff 3367 } ## end if ($pager =~ /^\|/)
e22ea7cc
RF
3368 else {
3369
69893cff 3370 # Redirect I/O. STDOUT already safe.
e22ea7cc
RF
3371 open( OUT, ">&STDOUT" ) # XXX: lost message
3372 || &warn("Can't restore DB::OUT");
3373 }
3374 next CMD;
69893cff
RGS
3375 } ## end unless ($piped = open(OUT,...
3376
3377 # Set up broken-pipe handler if necessary.
e22ea7cc
RF
3378 $SIG{PIPE} = \&DB::catch
3379 if $pager =~ /^\|/
3380 && ( "" eq $SIG{PIPE} || "DEFAULT" eq $SIG{PIPE} );
69893cff 3381
70c9432b
SF
3382 OUT->autoflush(1);
3383 # Save current filehandle, and put it back.
e22ea7cc 3384 $selected = select(OUT);
69893cff 3385 # Don't put it back if pager was a pipe.
e22ea7cc 3386 select($selected), $selected = "" unless $cmd =~ /^\|\|/;
69893cff
RGS
3387
3388 # Trim off the pipe symbols and run the command now.
ff41e38d 3389 $cmd =~ s#\A\|+\s*##;
e22ea7cc 3390 redo PIPE;
ff41e38d 3391 }
69893cff
RGS
3392
3393=head3 END OF COMMAND PARSING
3394
ff41e38d
SF
3395Anything left in C<$cmd> at this point is a Perl expression that we want to
3396evaluate. We'll always evaluate in the user's context, and fully qualify
69893cff
RGS
3397any variables we might want to address in the C<DB> package.
3398
3399=cut
3400
3401 # t - turn trace on.
ff41e38d
SF
3402 if ($cmd =~ s#\At\s+(\d+)?#\$DB::trace |= 1;\n#) {
3403 my $trace_arg = $1;
3404 $trace_to_depth = $trace_arg ? $stack_depth||0 + $1 : 1E9;
3405 }
69893cff
RGS
3406
3407 # s - single-step. Remember the last command was 's'.
ff41e38d
SF
3408 if ($cmd =~ s/\As\s/\$DB::single = 1;\n/) {
3409 $laststep = 's';
3410 }
69893cff
RGS
3411
3412 # n - single-step, but not into subs. Remember last command
e22ea7cc 3413 # was 'n'.
ff41e38d
SF
3414 if ($cmd =~ s#\An\s#\$DB::single = 2;\n#) {
3415 $laststep = 'n';
3416 }
69893cff 3417
e22ea7cc 3418 } # PIPE:
69893cff 3419
e22ea7cc 3420 # Make sure the flag that says "the debugger's running" is
69893cff 3421 # still on, to make sure we get control again.
e22ea7cc 3422 $evalarg = "\$^D = \$^D | \$DB::db_stop;\n$cmd";
69893cff
RGS
3423
3424 # Run *our* eval that executes in the caller's context.
e22ea7cc 3425 &eval;
69893cff
RGS
3426
3427 # Turn off the one-time-dump stuff now.
e22ea7cc
RF
3428 if ($onetimeDump) {
3429 $onetimeDump = undef;
69893cff 3430 $onetimedumpDepth = undef;
e22ea7cc
RF
3431 }
3432 elsif ( $term_pid == $$ ) {
c7e68384
IZ
3433 eval { # May run under miniperl, when not available...
3434 STDOUT->flush();
3435 STDERR->flush();
3436 };
e22ea7cc 3437
69893cff 3438 # XXX If this is the master pid, print a newline.
e22ea7cc
RF
3439 print $OUT "\n";
3440 }
3441 } ## end while (($term || &setterm...
69893cff
RGS
3442
3443=head3 POST-COMMAND PROCESSING
3444
3445After each command, we check to see if the command output was piped anywhere.
3446If so, we go through the necessary code to unhook the pipe and go back to
3447our standard filehandles for input and output.
3448
3449=cut
3450
e22ea7cc 3451 continue { # CMD:
69893cff
RGS
3452
3453 # At the end of every command:
e22ea7cc
RF
3454 if ($piped) {
3455
69893cff 3456 # Unhook the pipe mechanism now.
e22ea7cc
RF
3457 if ( $pager =~ /^\|/ ) {
3458
69893cff 3459 # No error from the child.
e22ea7cc 3460 $? = 0;
69893cff 3461
e22ea7cc
RF
3462 # we cannot warn here: the handle is missing --tchrist
3463 close(OUT) || print SAVEOUT "\nCan't close DB::OUT\n";
69893cff 3464
e22ea7cc 3465 # most of the $? crud was coping with broken cshisms
69893cff 3466 # $? is explicitly set to 0, so this never runs.
e22ea7cc 3467 if ($?) {
1f874cb6 3468 print SAVEOUT "Pager '$pager' failed: ";
e22ea7cc
RF
3469 if ( $? == -1 ) {
3470 print SAVEOUT "shell returned -1\n";
3471 }
3472 elsif ( $? >> 8 ) {
3473 print SAVEOUT ( $? & 127 )
3474 ? " (SIG#" . ( $? & 127 ) . ")"
3475 : "", ( $? & 128 ) ? " -- core dumped" : "", "\n";
3476 }
3477 else {
3478 print SAVEOUT "status ", ( $? >> 8 ), "\n";
3479 }
69893cff
RGS
3480 } ## end if ($?)
3481
e22ea7cc 3482 # Reopen filehandle for our output (if we can) and
69893cff 3483 # restore STDOUT (if we can).
e22ea7cc
RF
3484 open( OUT, ">&STDOUT" ) || &warn("Can't restore DB::OUT");
3485 open( STDOUT, ">&SAVEOUT" )
3486 || &warn("Can't restore STDOUT");
69893cff
RGS
3487
3488 # Turn off pipe exception handler if necessary.
e22ea7cc 3489 $SIG{PIPE} = "DEFAULT" if $SIG{PIPE} eq \&DB::catch;
69893cff 3490
e22ea7cc
RF
3491 # Will stop ignoring SIGPIPE if done like nohup(1)
3492 # does SIGINT but Perl doesn't give us a choice.
69893cff 3493 } ## end if ($pager =~ /^\|/)
e22ea7cc
RF
3494 else {
3495
69893cff 3496 # Non-piped "pager". Just restore STDOUT.
e22ea7cc
RF
3497 open( OUT, ">&SAVEOUT" ) || &warn("Can't restore DB::OUT");
3498 }
69893cff
RGS
3499
3500 # Close filehandle pager was using, restore the normal one
3501 # if necessary,
3502 close(SAVEOUT);
e22ea7cc 3503 select($selected), $selected = "" unless $selected eq "";
69893cff
RGS
3504
3505 # No pipes now.
e22ea7cc 3506 $piped = "";
69893cff 3507 } ## end if ($piped)
e22ea7cc 3508 } # CMD:
69893cff
RGS
3509
3510=head3 COMMAND LOOP TERMINATION
3511
3512When commands have finished executing, we come here. If the user closed the
3513input filehandle, we turn on C<$fall_off_end> to emulate a C<q> command. We
3514evaluate any post-prompt items. We restore C<$@>, C<$!>, C<$^E>, C<$,>, C<$/>,
3515C<$\>, and C<$^W>, and return a null list as expected by the Perl interpreter.
3516The interpreter will then execute the next line and then return control to us
3517again.
3518
3519=cut
3520
3521 # No more commands? Quit.
1f874cb6 3522 $fall_off_end = 1 unless defined $cmd; # Emulate 'q' on EOF
69893cff
RGS
3523
3524 # Evaluate post-prompt commands.
e22ea7cc
RF
3525 foreach $evalarg (@$post) {
3526 &eval;
3527 }
3528 } # if ($single || $signal)
69893cff
RGS
3529
3530 # Put the user's globals back where you found them.
e22ea7cc 3531 ( $@, $!, $^E, $,, $/, $\, $^W ) = @saved;
69893cff
RGS
3532 ();
3533} ## end sub DB
3534
3535# The following code may be executed now:
3536# BEGIN {warn 4}
3537
3538=head2 sub
3539
b570d64b 3540C<sub> is called whenever a subroutine call happens in the program being
69893cff
RGS
3541debugged. The variable C<$DB::sub> contains the name of the subroutine
3542being called.
3543
3544The core function of this subroutine is to actually call the sub in the proper
3545context, capturing its output. This of course causes C<DB::DB> to get called
3546again, repeating until the subroutine ends and returns control to C<DB::sub>
3547again. Once control returns, C<DB::sub> figures out whether or not to dump the
3548return value, and returns its captured copy of the return value as its own
3549return value. The value then feeds back into the program being debugged as if
3550C<DB::sub> hadn't been there at all.
3551
3552C<sub> does all the work of printing the subroutine entry and exit messages
3553enabled by setting C<$frame>. It notes what sub the autoloader got called for,
b570d64b 3554and also prints the return value if needed (for the C<r> command and if
69893cff
RGS
3555the 16 bit is set in C<$frame>).
3556
3557It also tracks the subroutine call depth by saving the c