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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
RGS
599
600=back
601
602=head3 The problem of lexicals
603
604The context of C<DB::eval()> presents us with some problems. Obviously,
605we want to be 'sandboxed' away from the debugger's internals when we do
606the eval, but we need some way to control how punctuation variables and
b570d64b 607debugger globals are used.
69893cff
RGS
608
609We can't use local, because the code inside C<DB::eval> can see localized
610variables; and we can't use C<my> either for the same reason. The code
611in this routine compromises and uses C<my>.
612
613After this routine is over, we don't have user code executing in the debugger's
614context, so we can use C<my> freely.
615
616=cut
617
618############################################## Begin lexical danger zone
619
620# 'my' variables used here could leak into (that is, be visible in)
621# the context that the code being evaluated is executing in. This means that
622# the code could modify the debugger's variables.
623#
624# Fiddling with the debugger's context could be Bad. We insulate things as
625# much as we can.
626
6b24a4b7
SF
627use vars qw(
628 @args
629 %break_on_load
630 @cmdfhs
631 $CommandSet
632 $CreateTTY
633 $DBGR
634 @dbline
635 $dbline
636 %dbline
637 $dieLevel
638 $evalarg
639 $filename
640 $frame
641 $hist
642 $histfile
643 $histsize
644 $ImmediateStop
645 $IN
646 $inhibit_exit
647 @ini_INC
648 $ini_warn
649 $line
650 $maxtrace
651 $od
652 $onetimeDump
653 $onetimedumpDepth
654 %option
655 @options
656 $osingle
657 $otrace
658 $OUT
659 $packname
660 $pager
661 $post
662 %postponed
663 $prc
664 $pre
665 $pretype
666 $psh
667 @RememberOnROptions
668 $remoteport
669 @res
670 $rl
671 @saved
672 $signal
673 $signalLevel
674 $single
675 $start
676 $sub
677 %sub
678 $subname
679 $term
680 $trace
681 $usercontext
682 $warnLevel
683 $window
684);
685
686# Used to save @ARGV and extract any debugger-related flags.
687use vars qw(@ARGS);
688
689# Used to prevent multiple entries to diesignal()
690# (if for instance diesignal() itself dies)
691use vars qw($panic);
692
693# Used to prevent the debugger from running nonstop
694# after a restart
695use vars qw($second_time);
696
697sub _calc_usercontext {
698 my ($package) = @_;
699
700 # Cancel strict completely for the evaluated code, so the code
701 # the user evaluates won't be affected by it. (Shlomi Fish)
702 return 'no strict; ($@, $!, $^E, $,, $/, $\, $^W) = @saved;'
703 . "package $package;"; # this won't let them modify, alas
704}
705
c1051fcf 706sub eval {
69893cff 707
c1051fcf 708 # 'my' would make it visible from user code
e22ea7cc 709 # but so does local! --tchrist
69893cff 710 # Remember: this localizes @DB::res, not @main::res.
c1051fcf
IZ
711 local @res;
712 {
e22ea7cc
RF
713
714 # Try to keep the user code from messing with us. Save these so that
715 # even if the eval'ed code changes them, we can put them back again.
716 # Needed because the user could refer directly to the debugger's
69893cff
RGS
717 # package globals (and any 'my' variables in this containing scope)
718 # inside the eval(), and we want to try to stay safe.
e22ea7cc 719 local $otrace = $trace;
69893cff
RGS
720 local $osingle = $single;
721 local $od = $^D;
722
723 # Untaint the incoming eval() argument.
724 { ($evalarg) = $evalarg =~ /(.*)/s; }
725
e22ea7cc 726 # $usercontext built in DB::DB near the comment
69893cff
RGS
727 # "set up the context for DB::eval ..."
728 # Evaluate and save any results.
e22ea7cc 729 @res = eval "$usercontext $evalarg;\n"; # '\n' for nice recursive debug
69893cff
RGS
730
731 # Restore those old values.
732 $trace = $otrace;
733 $single = $osingle;
734 $^D = $od;
c1051fcf 735 }
69893cff
RGS
736
737 # Save the current value of $@, and preserve it in the debugger's copy
738 # of the saved precious globals.
c1051fcf 739 my $at = $@;
69893cff
RGS
740
741 # Since we're only saving $@, we only have to localize the array element
742 # that it will be stored in.
e22ea7cc 743 local $saved[0]; # Preserve the old value of $@
c1051fcf 744 eval { &DB::save };
69893cff
RGS
745
746 # Now see whether we need to report an error back to the user.
c1051fcf 747 if ($at) {
69893cff
RGS
748 local $\ = '';
749 print $OUT $at;
750 }
751
752 # Display as required by the caller. $onetimeDump and $onetimedumpDepth
753 # are package globals.
754 elsif ($onetimeDump) {
e22ea7cc
RF
755 if ( $onetimeDump eq 'dump' ) {
756 local $option{dumpDepth} = $onetimedumpDepth
757 if defined $onetimedumpDepth;
758 dumpit( $OUT, \@res );
759 }
760 elsif ( $onetimeDump eq 'methods' ) {
761 methods( $res[0] );
762 }
69893cff 763 } ## end elsif ($onetimeDump)
c1051fcf 764 @res;
69893cff
RGS
765} ## end sub eval
766
767############################################## End lexical danger zone
c1051fcf 768
e22ea7cc
RF
769# After this point it is safe to introduce lexicals.
770# The code being debugged will be executing in its own context, and
69893cff 771# can't see the inside of the debugger.
d338d6fe 772#
e22ea7cc 773# However, one should not overdo it: leave as much control from outside as
69893cff
RGS
774# possible. If you make something a lexical, it's not going to be addressable
775# from outside the debugger even if you know its name.
776
d338d6fe
PP
777# This file is automatically included if you do perl -d.
778# It's probably not useful to include this yourself.
779#
e22ea7cc 780# Before venturing further into these twisty passages, it is
2f7e9187
MS
781# wise to read the perldebguts man page or risk the ire of dragons.
782#
69893cff
RGS
783# (It should be noted that perldebguts will tell you a lot about
784# the underlying mechanics of how the debugger interfaces into the
785# Perl interpreter, but not a lot about the debugger itself. The new
786# comments in this code try to address this problem.)
787
d338d6fe 788# Note that no subroutine call is possible until &DB::sub is defined
36477c24 789# (for subroutines defined outside of the package DB). In fact the same is
d338d6fe 790# true if $deep is not defined.
055fd3a9
GS
791
792# Enhanced by ilya@math.ohio-state.edu (Ilya Zakharevich)
055fd3a9
GS
793
794# modified Perl debugger, to be run from Emacs in perldb-mode
795# Ray Lischner (uunet!mntgfx!lisch) as of 5 Nov 1990
796# Johan Vromans -- upgrade to 4.0 pl 10
797# Ilya Zakharevich -- patches after 5.001 (and some before ;-)
6fae1ad7 798########################################################################
d338d6fe 799
69893cff
RGS
800=head1 DEBUGGER INITIALIZATION
801
802The debugger starts up in phases.
803
804=head2 BASIC SETUP
805
806First, it initializes the environment it wants to run in: turning off
807warnings during its own compilation, defining variables which it will need
808to avoid warnings later, setting itself up to not exit when the program
809terminates, and defaulting to printing return values for the C<r> command.
810
811=cut
812
eda6e075 813# Needed for the statement after exec():
69893cff
RGS
814#
815# This BEGIN block is simply used to switch off warnings during debugger
98dc9551 816# compilation. Probably it would be better practice to fix the warnings,
69893cff 817# but this is how it's done at the moment.
eda6e075 818
e22ea7cc
RF
819BEGIN {
820 $ini_warn = $^W;
821 $^W = 0;
822} # Switch compilation warnings off until another BEGIN.
d12a4851 823
69893cff
RGS
824local ($^W) = 0; # Switch run-time warnings off during init.
825
2cbb2ee1
RGS
826=head2 THREADS SUPPORT
827
828If we are running under a threaded Perl, we require threads and threads::shared
829if the environment variable C<PERL5DB_THREADED> is set, to enable proper
830threaded debugger control. C<-dt> can also be used to set this.
831
832Each new thread will be announced and the debugger prompt will always inform
833you of each new thread created. It will also indicate the thread id in which
834we are currently running within the prompt like this:
835
836 [tid] DB<$i>
837
838Where C<[tid]> is an integer thread id and C<$i> is the familiar debugger
839command prompt. The prompt will show: C<[0]> when running under threads, but
840not actually in a thread. C<[tid]> is consistent with C<gdb> usage.
841
842While running under threads, when you set or delete a breakpoint (etc.), this
b570d64b 843will apply to all threads, not just the currently running one. When you are
2cbb2ee1
RGS
844in a currently executing thread, you will stay there until it completes. With
845the current implementation it is not currently possible to hop from one thread
846to another.
847
848The C<e> and C<E> commands are currently fairly minimal - see C<h e> and C<h E>.
849
850Note that threading support was built into the debugger as of Perl version
851C<5.8.6> and debugger version C<1.2.8>.
852
853=cut
854
855BEGIN {
856 # ensure we can share our non-threaded variables or no-op
857 if ($ENV{PERL5DB_THREADED}) {
858 require threads;
859 require threads::shared;
860 import threads::shared qw(share);
861 $DBGR;
862 share(\$DBGR);
863 lock($DBGR);
864 print "Threads support enabled\n";
865 } else {
866 *lock = sub(*) {};
867 *share = sub(*) {};
868 }
869}
870
2218c045
SF
871# These variables control the execution of 'dumpvar.pl'.
872{
873 package dumpvar;
874 use vars qw(
875 $hashDepth
876 $arrayDepth
877 $dumpDBFiles
878 $dumpPackages
879 $quoteHighBit
880 $printUndef
881 $globPrint
882 $usageOnly
883 );
884}
69893cff 885
2218c045
SF
886# used to control die() reporting in diesignal()
887{
888 package Carp;
889 use vars qw($CarpLevel);
890}
d338d6fe 891
422c59bf 892# without threads, $filename is not defined until DB::DB is called
2cbb2ee1 893foreach my $k (keys (%INC)) {
fb4d8a6c 894 share(\$main::{'_<'.$filename}) if defined $filename;
2cbb2ee1
RGS
895};
896
54d04a52 897# Command-line + PERLLIB:
69893cff 898# Save the contents of @INC before they are modified elsewhere.
54d04a52
IZ
899@ini_INC = @INC;
900
69893cff
RGS
901# This was an attempt to clear out the previous values of various
902# trapped errors. Apparently it didn't help. XXX More info needed!
d338d6fe
PP
903# $prevwarn = $prevdie = $prevbus = $prevsegv = ''; # Does not help?!
904
69893cff
RGS
905# We set these variables to safe values. We don't want to blindly turn
906# off warnings, because other packages may still want them.
e22ea7cc
RF
907$trace = $signal = $single = 0; # Uninitialized warning suppression
908 # (local $^W cannot help - other packages!).
69893cff
RGS
909
910# Default to not exiting when program finishes; print the return
911# value when the 'r' command is used to return from a subroutine.
55497cff 912$inhibit_exit = $option{PrintRet} = 1;
d338d6fe 913
6b24a4b7
SF
914use vars qw($trace_to_depth);
915
5e2b42dd
SF
916# Default to 1E9 so it won't be limited to a certain recursion depth.
917$trace_to_depth = 1E9;
bdba49ad 918
69893cff
RGS
919=head1 OPTION PROCESSING
920
b570d64b
SF
921The debugger's options are actually spread out over the debugger itself and
922C<dumpvar.pl>; some of these are variables to be set, while others are
69893cff
RGS
923subs to be called with a value. To try to make this a little easier to
924manage, the debugger uses a few data structures to define what options
925are legal and how they are to be processed.
926
927First, the C<@options> array defines the I<names> of all the options that
928are to be accepted.
929
930=cut
931
932@options = qw(
5561b870 933 CommandSet HistFile HistSize
e22ea7cc
RF
934 hashDepth arrayDepth dumpDepth
935 DumpDBFiles DumpPackages DumpReused
936 compactDump veryCompact quote
937 HighBit undefPrint globPrint
938 PrintRet UsageOnly frame
939 AutoTrace TTY noTTY
940 ReadLine NonStop LineInfo
941 maxTraceLen recallCommand ShellBang
942 pager tkRunning ornaments
943 signalLevel warnLevel dieLevel
944 inhibit_exit ImmediateStop bareStringify
945 CreateTTY RemotePort windowSize
584420f0 946 DollarCaretP
e22ea7cc 947);
d12a4851 948
584420f0 949@RememberOnROptions = qw(DollarCaretP);
d12a4851 950
69893cff
RGS
951=pod
952
953Second, C<optionVars> lists the variables that each option uses to save its
954state.
955
956=cut
957
6b24a4b7
SF
958use vars qw(%optionVars);
959
69893cff 960%optionVars = (
e22ea7cc
RF
961 hashDepth => \$dumpvar::hashDepth,
962 arrayDepth => \$dumpvar::arrayDepth,
963 CommandSet => \$CommandSet,
964 DumpDBFiles => \$dumpvar::dumpDBFiles,
965 DumpPackages => \$dumpvar::dumpPackages,
966 DumpReused => \$dumpvar::dumpReused,
967 HighBit => \$dumpvar::quoteHighBit,
968 undefPrint => \$dumpvar::printUndef,
969 globPrint => \$dumpvar::globPrint,
970 UsageOnly => \$dumpvar::usageOnly,
971 CreateTTY => \$CreateTTY,
972 bareStringify => \$dumpvar::bareStringify,
973 frame => \$frame,
974 AutoTrace => \$trace,
975 inhibit_exit => \$inhibit_exit,
976 maxTraceLen => \$maxtrace,
977 ImmediateStop => \$ImmediateStop,
978 RemotePort => \$remoteport,
979 windowSize => \$window,
5561b870
AK
980 HistFile => \$histfile,
981 HistSize => \$histsize,
69893cff
RGS
982);
983
984=pod
985
986Third, C<%optionAction> defines the subroutine to be called to process each
987option.
988
b570d64b 989=cut
69893cff 990
6b24a4b7
SF
991use vars qw(%optionAction);
992
69893cff
RGS
993%optionAction = (
994 compactDump => \&dumpvar::compactDump,
995 veryCompact => \&dumpvar::veryCompact,
996 quote => \&dumpvar::quote,
997 TTY => \&TTY,
998 noTTY => \&noTTY,
999 ReadLine => \&ReadLine,
1000 NonStop => \&NonStop,
1001 LineInfo => \&LineInfo,
1002 recallCommand => \&recallCommand,
1003 ShellBang => \&shellBang,
1004 pager => \&pager,
1005 signalLevel => \&signalLevel,
1006 warnLevel => \&warnLevel,
1007 dieLevel => \&dieLevel,
1008 tkRunning => \&tkRunning,
1009 ornaments => \&ornaments,
1010 RemotePort => \&RemotePort,
1011 DollarCaretP => \&DollarCaretP,
d12a4851
JH
1012);
1013
69893cff
RGS
1014=pod
1015
1016Last, the C<%optionRequire> notes modules that must be C<require>d if an
1017option is used.
1018
1019=cut
d338d6fe 1020
69893cff
RGS
1021# Note that this list is not complete: several options not listed here
1022# actually require that dumpvar.pl be loaded for them to work, but are
1023# not in the table. A subsequent patch will correct this problem; for
1024# the moment, we're just recommenting, and we are NOT going to change
1025# function.
6b24a4b7
SF
1026use vars qw(%optionRequire);
1027
eda6e075 1028%optionRequire = (
69893cff
RGS
1029 compactDump => 'dumpvar.pl',
1030 veryCompact => 'dumpvar.pl',
1031 quote => 'dumpvar.pl',
e22ea7cc 1032);
69893cff
RGS
1033
1034=pod
1035
1036There are a number of initialization-related variables which can be set
1037by putting code to set them in a BEGIN block in the C<PERL5DB> environment
1038variable. These are:
1039
1040=over 4
1041
1042=item C<$rl> - readline control XXX needs more explanation
1043
1044=item C<$warnLevel> - whether or not debugger takes over warning handling
1045
1046=item C<$dieLevel> - whether or not debugger takes over die handling
1047
1048=item C<$signalLevel> - whether or not debugger takes over signal handling
1049
1050=item C<$pre> - preprompt actions (array reference)
1051
1052=item C<$post> - postprompt actions (array reference)
1053
1054=item C<$pretype>
1055
1056=item C<$CreateTTY> - whether or not to create a new TTY for this debugger
1057
1058=item C<$CommandSet> - which command set to use (defaults to new, documented set)
1059
1060=back
1061
1062=cut
d338d6fe
PP
1063
1064# These guys may be defined in $ENV{PERL5DB} :
69893cff
RGS
1065$rl = 1 unless defined $rl;
1066$warnLevel = 1 unless defined $warnLevel;
1067$dieLevel = 1 unless defined $dieLevel;
1068$signalLevel = 1 unless defined $signalLevel;
1069$pre = [] unless defined $pre;
1070$post = [] unless defined $post;
1071$pretype = [] unless defined $pretype;
1072$CreateTTY = 3 unless defined $CreateTTY;
1073$CommandSet = '580' unless defined $CommandSet;
1074
2cbb2ee1
RGS
1075share($rl);
1076share($warnLevel);
1077share($dieLevel);
1078share($signalLevel);
1079share($pre);
1080share($post);
1081share($pretype);
1082share($rl);
1083share($CreateTTY);
1084share($CommandSet);
1085
69893cff
RGS
1086=pod
1087
1088The default C<die>, C<warn>, and C<signal> handlers are set up.
1089
1090=cut
055fd3a9 1091
d338d6fe
PP
1092warnLevel($warnLevel);
1093dieLevel($dieLevel);
1094signalLevel($signalLevel);
055fd3a9 1095
69893cff
RGS
1096=pod
1097
1098The pager to be used is needed next. We try to get it from the
5561b870 1099environment first. If it's not defined there, we try to find it in
69893cff
RGS
1100the Perl C<Config.pm>. If it's not there, we default to C<more>. We
1101then call the C<pager()> function to save the pager name.
1102
1103=cut
1104
1105# This routine makes sure $pager is set up so that '|' can use it.
4865a36d 1106pager(
e22ea7cc 1107
69893cff 1108 # If PAGER is defined in the environment, use it.
e22ea7cc
RF
1109 defined $ENV{PAGER}
1110 ? $ENV{PAGER}
69893cff
RGS
1111
1112 # If not, see if Config.pm defines it.
e22ea7cc
RF
1113 : eval { require Config }
1114 && defined $Config::Config{pager}
1115 ? $Config::Config{pager}
69893cff
RGS
1116
1117 # If not, fall back to 'more'.
e22ea7cc
RF
1118 : 'more'
1119 )
1120 unless defined $pager;
69893cff
RGS
1121
1122=pod
1123
1124We set up the command to be used to access the man pages, the command
be9a9b1d
AT
1125recall character (C<!> unless otherwise defined) and the shell escape
1126character (C<!> unless otherwise defined). Yes, these do conflict, and
69893cff
RGS
1127neither works in the debugger at the moment.
1128
1129=cut
1130
055fd3a9 1131setman();
69893cff
RGS
1132
1133# Set up defaults for command recall and shell escape (note:
1134# these currently don't work in linemode debugging).
2218c045
SF
1135recallCommand("!") unless defined $prc;
1136shellBang("!") unless defined $psh;
69893cff
RGS
1137
1138=pod
1139
1140We then set up the gigantic string containing the debugger help.
1141We also set the limit on the number of arguments we'll display during a
1142trace.
1143
1144=cut
1145
04e43a21 1146sethelp();
69893cff
RGS
1147
1148# If we didn't get a default for the length of eval/stack trace args,
1149# set it here.
1d06cb2d 1150$maxtrace = 400 unless defined $maxtrace;
69893cff
RGS
1151
1152=head2 SETTING UP THE DEBUGGER GREETING
1153
be9a9b1d 1154The debugger I<greeting> helps to inform the user how many debuggers are
69893cff
RGS
1155running, and whether the current debugger is the primary or a child.
1156
1157If we are the primary, we just hang onto our pid so we'll have it when
1158or if we start a child debugger. If we are a child, we'll set things up
1159so we'll have a unique greeting and so the parent will give us our own
1160TTY later.
1161
1162We save the current contents of the C<PERLDB_PIDS> environment variable
1163because we mess around with it. We'll also need to hang onto it because
1164we'll need it if we restart.
1165
1166Child debuggers make a label out of the current PID structure recorded in
1167PERLDB_PIDS plus the new PID. They also mark themselves as not having a TTY
1168yet so the parent will give them one later via C<resetterm()>.
1169
1170=cut
1171
e22ea7cc 1172# Save the current contents of the environment; we're about to
69893cff 1173# much with it. We'll need this if we have to restart.
6b24a4b7 1174use vars qw($ini_pids);
f1583d8f 1175$ini_pids = $ENV{PERLDB_PIDS};
69893cff 1176
6b24a4b7
SF
1177use vars qw ($pids $term_pid);
1178
e22ea7cc
RF
1179if ( defined $ENV{PERLDB_PIDS} ) {
1180
69893cff 1181 # We're a child. Make us a label out of the current PID structure
e22ea7cc 1182 # recorded in PERLDB_PIDS plus our (new) PID. Mark us as not having
69893cff 1183 # a term yet so the parent will give us one later via resetterm().
55f4245e
JM
1184
1185 my $env_pids = $ENV{PERLDB_PIDS};
1186 $pids = "[$env_pids]";
1187
1188 # Unless we are on OpenVMS, all programs under the DCL shell run under
1189 # the same PID.
1190
1191 if (($^O eq 'VMS') && ($env_pids =~ /\b$$\b/)) {
1192 $term_pid = $$;
1193 }
1194 else {
1195 $ENV{PERLDB_PIDS} .= "->$$";
1196 $term_pid = -1;
1197 }
1198
69893cff
RGS
1199} ## end if (defined $ENV{PERLDB_PIDS...
1200else {
e22ea7cc
RF
1201
1202 # We're the parent PID. Initialize PERLDB_PID in case we end up with a
69893cff
RGS
1203 # child debugger, and mark us as the parent, so we'll know to set up
1204 # more TTY's is we have to.
1205 $ENV{PERLDB_PIDS} = "$$";
619a0444 1206 $pids = "[pid=$$]";
e22ea7cc 1207 $term_pid = $$;
f1583d8f 1208}
69893cff 1209
6b24a4b7 1210use vars qw($pidprompt);
f1583d8f 1211$pidprompt = '';
69893cff
RGS
1212
1213# Sets up $emacs as a synonym for $slave_editor.
6b24a4b7 1214use vars qw($slave_editor);
69893cff
RGS
1215*emacs = $slave_editor if $slave_editor; # May be used in afterinit()...
1216
1217=head2 READING THE RC FILE
1218
b570d64b 1219The debugger will read a file of initialization options if supplied. If
69893cff
RGS
1220running interactively, this is C<.perldb>; if not, it's C<perldb.ini>.
1221
b570d64b 1222=cut
69893cff
RGS
1223
1224# As noted, this test really doesn't check accurately that the debugger
1225# is running at a terminal or not.
d338d6fe 1226
6b24a4b7 1227use vars qw($rcfile);
fb4d8a6c
SF
1228{
1229 my $dev_tty = (($^O eq 'VMS') ? 'TT:' : '/dev/tty');
1230 # this is the wrong metric!
1231 $rcfile = ((-e $dev_tty) ? ".perldb" : "perldb.ini");
d338d6fe
PP
1232}
1233
69893cff
RGS
1234=pod
1235
1236The debugger does a safety test of the file to be read. It must be owned
1237either by the current user or root, and must only be writable by the owner.
1238
1239=cut
1240
1241# This wraps a safety test around "do" to read and evaluate the init file.
1242#
055fd3a9
GS
1243# This isn't really safe, because there's a race
1244# between checking and opening. The solution is to
1245# open and fstat the handle, but then you have to read and
1246# eval the contents. But then the silly thing gets
69893cff
RGS
1247# your lexical scope, which is unfortunate at best.
1248sub safe_do {
055fd3a9
GS
1249 my $file = shift;
1250
1251 # Just exactly what part of the word "CORE::" don't you understand?
69893cff
RGS
1252 local $SIG{__WARN__};
1253 local $SIG{__DIE__};
055fd3a9 1254
e22ea7cc 1255 unless ( is_safe_file($file) ) {
69893cff 1256 CORE::warn <<EO_GRIPE;
055fd3a9 1257perldb: Must not source insecure rcfile $file.
b570d64b 1258 You or the superuser must be the owner, and it must not
69893cff 1259 be writable by anyone but its owner.
055fd3a9 1260EO_GRIPE
69893cff
RGS
1261 return;
1262 } ## end unless (is_safe_file($file...
055fd3a9
GS
1263
1264 do $file;
1265 CORE::warn("perldb: couldn't parse $file: $@") if $@;
69893cff 1266} ## end sub safe_do
055fd3a9 1267
69893cff
RGS
1268# This is the safety test itself.
1269#
055fd3a9
GS
1270# Verifies that owner is either real user or superuser and that no
1271# one but owner may write to it. This function is of limited use
1272# when called on a path instead of upon a handle, because there are
1273# no guarantees that filename (by dirent) whose file (by ino) is
e22ea7cc 1274# eventually accessed is the same as the one tested.
055fd3a9
GS
1275# Assumes that the file's existence is not in doubt.
1276sub is_safe_file {
1277 my $path = shift;
69893cff 1278 stat($path) || return; # mysteriously vaporized
e22ea7cc 1279 my ( $dev, $ino, $mode, $nlink, $uid, $gid ) = stat(_);
055fd3a9
GS
1280
1281 return 0 if $uid != 0 && $uid != $<;
1282 return 0 if $mode & 022;
1283 return 1;
69893cff 1284} ## end sub is_safe_file
055fd3a9 1285
69893cff 1286# If the rcfile (whichever one we decided was the right one to read)
e22ea7cc
RF
1287# exists, we safely do it.
1288if ( -f $rcfile ) {
055fd3a9 1289 safe_do("./$rcfile");
69893cff 1290}
e22ea7cc 1291
69893cff 1292# If there isn't one here, try the user's home directory.
e22ea7cc 1293elsif ( defined $ENV{HOME} && -f "$ENV{HOME}/$rcfile" ) {
055fd3a9
GS
1294 safe_do("$ENV{HOME}/$rcfile");
1295}
e22ea7cc 1296
69893cff 1297# Else try the login directory.
e22ea7cc 1298elsif ( defined $ENV{LOGDIR} && -f "$ENV{LOGDIR}/$rcfile" ) {
055fd3a9 1299 safe_do("$ENV{LOGDIR}/$rcfile");
d338d6fe
PP
1300}
1301
69893cff 1302# If the PERLDB_OPTS variable has options in it, parse those out next.
e22ea7cc
RF
1303if ( defined $ENV{PERLDB_OPTS} ) {
1304 parse_options( $ENV{PERLDB_OPTS} );
d338d6fe
PP
1305}
1306
69893cff
RGS
1307=pod
1308
1309The last thing we do during initialization is determine which subroutine is
1310to be used to obtain a new terminal when a new debugger is started. Right now,
b0b54b5e 1311the debugger only handles TCP sockets, X11, OS/2, amd Mac OS X
11653f7f 1312(darwin).
69893cff
RGS
1313
1314=cut
1315
1316# Set up the get_fork_TTY subroutine to be aliased to the proper routine.
1317# Works if you're running an xterm or xterm-like window, or you're on
6fae1ad7
RF
1318# OS/2, or on Mac OS X. This may need some expansion.
1319
1320if (not defined &get_fork_TTY) # only if no routine exists
69893cff 1321{
b570d64b 1322 if ( defined $remoteport ) {
11653f7f
JJ
1323 # Expect an inetd-like server
1324 *get_fork_TTY = \&socket_get_fork_TTY; # to listen to us
1325 }
1326 elsif (defined $ENV{TERM} # If we know what kind
6fae1ad7
RF
1327 # of terminal this is,
1328 and $ENV{TERM} eq 'xterm' # and it's an xterm,
1329 and defined $ENV{DISPLAY} # and what display it's on,
1330 )
1331 {
1332 *get_fork_TTY = \&xterm_get_fork_TTY; # use the xterm version
1333 }
1334 elsif ( $^O eq 'os2' ) { # If this is OS/2,
1335 *get_fork_TTY = \&os2_get_fork_TTY; # use the OS/2 version
1336 }
1337 elsif ( $^O eq 'darwin' # If this is Mac OS X
1338 and defined $ENV{TERM_PROGRAM} # and we're running inside
1339 and $ENV{TERM_PROGRAM}
1340 eq 'Apple_Terminal' # Terminal.app
1341 )
1342 {
1343 *get_fork_TTY = \&macosx_get_fork_TTY; # use the Mac OS X version
1344 }
69893cff 1345} ## end if (not defined &get_fork_TTY...
e22ea7cc 1346
dbb46cec
DQ
1347# untaint $^O, which may have been tainted by the last statement.
1348# see bug [perl #24674]
e22ea7cc
RF
1349$^O =~ m/^(.*)\z/;
1350$^O = $1;
f1583d8f 1351
d12a4851 1352# Here begin the unreadable code. It needs fixing.
055fd3a9 1353
69893cff
RGS
1354=head2 RESTART PROCESSING
1355
1356This section handles the restart command. When the C<R> command is invoked, it
1357tries to capture all of the state it can into environment variables, and
1358then sets C<PERLDB_RESTART>. When we start executing again, we check to see
1359if C<PERLDB_RESTART> is there; if so, we reload all the information that
1360the R command stuffed into the environment variables.
1361
b570d64b 1362 PERLDB_RESTART - flag only, contains no restart data itself.
69893cff
RGS
1363 PERLDB_HIST - command history, if it's available
1364 PERLDB_ON_LOAD - breakpoints set by the rc file
1365 PERLDB_POSTPONE - subs that have been loaded/not executed, and have actions
1366 PERLDB_VISITED - files that had breakpoints
1367 PERLDB_FILE_... - breakpoints for a file
1368 PERLDB_OPT - active options
1369 PERLDB_INC - the original @INC
1370 PERLDB_PRETYPE - preprompt debugger actions
1371 PERLDB_PRE - preprompt Perl code
1372 PERLDB_POST - post-prompt Perl code
1373 PERLDB_TYPEAHEAD - typeahead captured by readline()
1374
1375We chug through all these variables and plug the values saved in them
1376back into the appropriate spots in the debugger.
1377
1378=cut
1379
6b24a4b7
SF
1380use vars qw(@hist @truehist %postponed_file @typeahead);
1381
e18a02a6 1382sub _restore_breakpoints_and_actions {
e22ea7cc 1383
e22ea7cc 1384 my @had_breakpoints = get_list("PERLDB_VISITED");
e18a02a6 1385
bdba49ad
SF
1386 for my $file_idx ( 0 .. $#had_breakpoints ) {
1387 my $filename = $had_breakpoints[$file_idx];
1388 my %pf = get_list("PERLDB_FILE_$file_idx");
1389 $postponed_file{ $filename } = \%pf if %pf;
1390 my @lines = sort {$a <=> $b} keys(%pf);
1391 my @enabled_statuses = get_list("PERLDB_FILE_ENABLED_$file_idx");
1392 for my $line_idx (0 .. $#lines) {
1393 _set_breakpoint_enabled_status(
1394 $filename,
1395 $lines[$line_idx],
1396 ($enabled_statuses[$line_idx] ? 1 : ''),
1397 );
1398 }
e22ea7cc 1399 }
69893cff 1400
e18a02a6
SF
1401 return;
1402}
1403
1404if ( exists $ENV{PERLDB_RESTART} ) {
1405
1406 # We're restarting, so we don't need the flag that says to restart anymore.
1407 delete $ENV{PERLDB_RESTART};
1408
1409 # $restart = 1;
1410 @hist = get_list('PERLDB_HIST');
1411 %break_on_load = get_list("PERLDB_ON_LOAD");
1412 %postponed = get_list("PERLDB_POSTPONE");
1413
1414 share(@hist);
1415 share(@truehist);
1416 share(%break_on_load);
1417 share(%postponed);
1418
1419 _restore_breakpoints_and_actions();
1420
69893cff 1421 # restore options
e22ea7cc
RF
1422 my %opt = get_list("PERLDB_OPT");
1423 my ( $opt, $val );
1424 while ( ( $opt, $val ) = each %opt ) {
1425 $val =~ s/[\\\']/\\$1/g;
1426 parse_options("$opt'$val'");
1427 }
69893cff
RGS
1428
1429 # restore original @INC
e22ea7cc
RF
1430 @INC = get_list("PERLDB_INC");
1431 @ini_INC = @INC;
1432
1433 # return pre/postprompt actions and typeahead buffer
1434 $pretype = [ get_list("PERLDB_PRETYPE") ];
1435 $pre = [ get_list("PERLDB_PRE") ];
1436 $post = [ get_list("PERLDB_POST") ];
1437 @typeahead = get_list( "PERLDB_TYPEAHEAD", @typeahead );
69893cff
RGS
1438} ## end if (exists $ENV{PERLDB_RESTART...
1439
1440=head2 SETTING UP THE TERMINAL
1441
1442Now, we'll decide how the debugger is going to interact with the user.
1443If there's no TTY, we set the debugger to run non-stop; there's not going
1444to be anyone there to enter commands.
1445
1446=cut
54d04a52 1447
6b24a4b7
SF
1448use vars qw($notty $runnonstop $console $tty $LINEINFO);
1449use vars qw($lineinfo $doccmd);
1450
d338d6fe 1451if ($notty) {
69893cff 1452 $runnonstop = 1;
2cbb2ee1 1453 share($runnonstop);
69893cff 1454}
d12a4851 1455
69893cff
RGS
1456=pod
1457
1458If there is a TTY, we have to determine who it belongs to before we can
1459proceed. If this is a slave editor or graphical debugger (denoted by
1460the first command-line switch being '-emacs'), we shift this off and
1461set C<$rl> to 0 (XXX ostensibly to do straight reads).
1462
1463=cut
1464
1465else {
e22ea7cc 1466
69893cff
RGS
1467 # Is Perl being run from a slave editor or graphical debugger?
1468 # If so, don't use readline, and set $slave_editor = 1.
e22ea7cc
RF
1469 $slave_editor =
1470 ( ( defined $main::ARGV[0] ) and ( $main::ARGV[0] eq '-emacs' ) );
1471 $rl = 0, shift(@main::ARGV) if $slave_editor;
1472
1473 #require Term::ReadLine;
d12a4851 1474
69893cff
RGS
1475=pod
1476
1477We then determine what the console should be on various systems:
1478
1479=over 4
1480
1481=item * Cygwin - We use C<stdin> instead of a separate device.
1482
1483=cut
1484
e22ea7cc
RF
1485 if ( $^O eq 'cygwin' ) {
1486
69893cff
RGS
1487 # /dev/tty is binary. use stdin for textmode
1488 undef $console;
1489 }
1490
1491=item * Unix - use C</dev/tty>.
1492
1493=cut
1494
e22ea7cc 1495 elsif ( -e "/dev/tty" ) {
69893cff
RGS
1496 $console = "/dev/tty";
1497 }
1498
1499=item * Windows or MSDOS - use C<con>.
1500
1501=cut
1502
e22ea7cc 1503 elsif ( $^O eq 'dos' or -e "con" or $^O eq 'MSWin32' ) {
69893cff
RGS
1504 $console = "con";
1505 }
1506
69893cff
RGS
1507=item * VMS - use C<sys$command>.
1508
1509=cut
1510
1511 else {
e22ea7cc 1512
69893cff
RGS
1513 # everything else is ...
1514 $console = "sys\$command";
d12a4851 1515 }
69893cff
RGS
1516
1517=pod
1518
1519=back
1520
1521Several other systems don't use a specific console. We C<undef $console>
1522for those (Windows using a slave editor/graphical debugger, NetWare, OS/2
1523with a slave editor, Epoc).
1524
1525=cut
d12a4851 1526
e22ea7cc
RF
1527 if ( ( $^O eq 'MSWin32' ) and ( $slave_editor or defined $ENV{EMACS} ) ) {
1528
69893cff 1529 # /dev/tty is binary. use stdin for textmode
e22ea7cc
RF
1530 $console = undef;
1531 }
1532
1533 if ( $^O eq 'NetWare' ) {
d12a4851 1534
69893cff
RGS
1535 # /dev/tty is binary. use stdin for textmode
1536 $console = undef;
1537 }
d12a4851 1538
69893cff
RGS
1539 # In OS/2, we need to use STDIN to get textmode too, even though
1540 # it pretty much looks like Unix otherwise.
e22ea7cc
RF
1541 if ( defined $ENV{OS2_SHELL} and ( $slave_editor or $ENV{WINDOWID} ) )
1542 { # In OS/2
1543 $console = undef;
1544 }
1545
1546 # EPOC also falls into the 'got to use STDIN' camp.
1547 if ( $^O eq 'epoc' ) {
1548 $console = undef;
1549 }
d12a4851 1550
69893cff
RGS
1551=pod
1552
1553If there is a TTY hanging around from a parent, we use that as the console.
1554
1555=cut
1556
e22ea7cc 1557 $console = $tty if defined $tty;
d12a4851 1558
b570d64b 1559=head2 SOCKET HANDLING
69893cff
RGS
1560
1561The debugger is capable of opening a socket and carrying out a debugging
1562session over the socket.
1563
1564If C<RemotePort> was defined in the options, the debugger assumes that it
1565should try to start a debugging session on that port. It builds the socket
1566and then tries to connect the input and output filehandles to it.
1567
1568=cut
1569
1570 # Handle socket stuff.
e22ea7cc
RF
1571
1572 if ( defined $remoteport ) {
1573
69893cff
RGS
1574 # If RemotePort was defined in the options, connect input and output
1575 # to the socket.
11653f7f 1576 $IN = $OUT = connect_remoteport();
69893cff
RGS
1577 } ## end if (defined $remoteport)
1578
1579=pod
1580
1581If no C<RemotePort> was defined, and we want to create a TTY on startup,
1582this is probably a situation where multiple debuggers are running (for example,
1583a backticked command that starts up another debugger). We create a new IN and
1584OUT filehandle, and do the necessary mojo to create a new TTY if we know how
1585and if we can.
1586
1587=cut
1588
1589 # Non-socket.
1590 else {
e22ea7cc 1591
69893cff
RGS
1592 # Two debuggers running (probably a system or a backtick that invokes
1593 # the debugger itself under the running one). create a new IN and OUT
e22ea7cc 1594 # filehandle, and do the necessary mojo to create a new tty if we
69893cff 1595 # know how, and we can.
e22ea7cc
RF
1596 create_IN_OUT(4) if $CreateTTY & 4;
1597 if ($console) {
1598
69893cff 1599 # If we have a console, check to see if there are separate ins and
cd1191f1 1600 # outs to open. (They are assumed identical if not.)
69893cff 1601
e22ea7cc
RF
1602 my ( $i, $o ) = split /,/, $console;
1603 $o = $i unless defined $o;
69893cff 1604
69893cff 1605 # read/write on in, or just read, or read on STDIN.
e22ea7cc
RF
1606 open( IN, "+<$i" )
1607 || open( IN, "<$i" )
1608 || open( IN, "<&STDIN" );
1609
69893cff
RGS
1610 # read/write/create/clobber out, or write/create/clobber out,
1611 # or merge with STDERR, or merge with STDOUT.
e22ea7cc
RF
1612 open( OUT, "+>$o" )
1613 || open( OUT, ">$o" )
1614 || open( OUT, ">&STDERR" )
1615 || open( OUT, ">&STDOUT" ); # so we don't dongle stdout
1616
1617 } ## end if ($console)
1618 elsif ( not defined $console ) {
1619
1620 # No console. Open STDIN.
1621 open( IN, "<&STDIN" );
1622
1623 # merge with STDERR, or with STDOUT.
1624 open( OUT, ">&STDERR" )
1625 || open( OUT, ">&STDOUT" ); # so we don't dongle stdout
1626 $console = 'STDIN/OUT';
69893cff
RGS
1627 } ## end elsif (not defined $console)
1628
1629 # Keep copies of the filehandles so that when the pager runs, it
1630 # can close standard input without clobbering ours.
e22ea7cc
RF
1631 $IN = \*IN, $OUT = \*OUT if $console or not defined $console;
1632 } ## end elsif (from if(defined $remoteport))
1633
1634 # Unbuffer DB::OUT. We need to see responses right away.
70c9432b 1635 $OUT->autoflush(1);
e22ea7cc
RF
1636
1637 # Line info goes to debugger output unless pointed elsewhere.
1638 # Pointing elsewhere makes it possible for slave editors to
1639 # keep track of file and position. We have both a filehandle
1640 # and a I/O description to keep track of.
1641 $LINEINFO = $OUT unless defined $LINEINFO;
1642 $lineinfo = $console unless defined $lineinfo;
2cbb2ee1 1643 # share($LINEINFO); # <- unable to share globs
b570d64b 1644 share($lineinfo); #
e22ea7cc 1645
69893cff
RGS
1646=pod
1647
1648To finish initialization, we show the debugger greeting,
1649and then call the C<afterinit()> subroutine if there is one.
1650
1651=cut
d12a4851 1652
e22ea7cc
RF
1653 # Show the debugger greeting.
1654 $header =~ s/.Header: ([^,]+),v(\s+\S+\s+\S+).*$/$1$2/;
1655 unless ($runnonstop) {
1656 local $\ = '';
1657 local $, = '';
1658 if ( $term_pid eq '-1' ) {
1659 print $OUT "\nDaughter DB session started...\n";
1660 }
1661 else {
1662 print $OUT "\nLoading DB routines from $header\n";
1663 print $OUT (
1664 "Editor support ",
1665 $slave_editor ? "enabled" : "available", ".\n"
1666 );
1667 print $OUT
1f874cb6 1668"\nEnter h or 'h h' for help, or '$doccmd perldebug' for more help.\n\n";
69893cff
RGS
1669 } ## end else [ if ($term_pid eq '-1')
1670 } ## end unless ($runnonstop)
1671} ## end else [ if ($notty)
1672
1673# XXX This looks like a bug to me.
1674# Why copy to @ARGS and then futz with @args?
d338d6fe 1675@ARGS = @ARGV;
6b24a4b7 1676# for (@args) {
69893cff
RGS
1677 # Make sure backslashes before single quotes are stripped out, and
1678 # keep args unless they are numeric (XXX why?)
e22ea7cc
RF
1679 # s/\'/\\\'/g; # removed while not justified understandably
1680 # s/(.*)/'$1'/ unless /^-?[\d.]+$/; # ditto
6b24a4b7 1681# }
d338d6fe 1682
e22ea7cc 1683# If there was an afterinit() sub defined, call it. It will get
69893cff 1684# executed in our scope, so it can fiddle with debugger globals.
e22ea7cc 1685if ( defined &afterinit ) { # May be defined in $rcfile
69893cff 1686 &afterinit();
d338d6fe 1687}
e22ea7cc 1688
69893cff 1689# Inform us about "Stack dump during die enabled ..." in dieLevel().
6b24a4b7
SF
1690use vars qw($I_m_init);
1691
43aed9ee
IZ
1692$I_m_init = 1;
1693
d338d6fe
PP
1694############################################################ Subroutines
1695
69893cff
RGS
1696=head1 SUBROUTINES
1697
1698=head2 DB
1699
1700This gigantic subroutine is the heart of the debugger. Called before every
1701statement, its job is to determine if a breakpoint has been reached, and
1702stop if so; read commands from the user, parse them, and execute
b468dcb6 1703them, and then send execution off to the next statement.
69893cff
RGS
1704
1705Note that the order in which the commands are processed is very important;
1706some commands earlier in the loop will actually alter the C<$cmd> variable
be9a9b1d 1707to create other commands to be executed later. This is all highly I<optimized>
69893cff
RGS
1708but can be confusing. Check the comments for each C<$cmd ... && do {}> to
1709see what's happening in any given command.
1710
1711=cut
1712
6b24a4b7
SF
1713use vars qw(
1714 $action
1715 %alias
1716 $cmd
1717 $doret
1718 $fall_off_end
1719 $file
1720 $filename_ini
1721 $finished
1722 %had_breakpoints
1723 $incr
1724 $laststep
1725 $level
1726 $max
1727 @old_watch
1728 $package
1729 $rc
1730 $sh
1731 @stack
1732 $stack_depth
1733 @to_watch
1734 $try
2c247e84 1735 $end
6b24a4b7
SF
1736);
1737
d338d6fe 1738sub DB {
69893cff 1739
2cbb2ee1
RGS
1740 # lock the debugger and get the thread id for the prompt
1741 lock($DBGR);
1742 my $tid;
6b24a4b7
SF
1743 my $position;
1744 my ($prefix, $after, $infix);
1745 my $pat;
6b24a4b7 1746
2cbb2ee1 1747 if ($ENV{PERL5DB_THREADED}) {
878090d5 1748 $tid = eval { "[".threads->tid."]" };
2cbb2ee1
RGS
1749 }
1750
69893cff 1751 # Check for whether we should be running continuously or not.
36477c24 1752 # _After_ the perl program is compiled, $single is set to 1:
e22ea7cc
RF
1753 if ( $single and not $second_time++ ) {
1754
69893cff 1755 # Options say run non-stop. Run until we get an interrupt.
e22ea7cc
RF
1756 if ($runnonstop) { # Disable until signal
1757 # If there's any call stack in place, turn off single
1758 # stepping into subs throughout the stack.
2c247e84 1759 for my $i (0 .. $stack_depth) {
72d7d80d 1760 $stack[ $i ] &= ~1;
e22ea7cc
RF
1761 }
1762
69893cff 1763 # And we are now no longer in single-step mode.
e22ea7cc 1764 $single = 0;
69893cff
RGS
1765
1766 # If we simply returned at this point, we wouldn't get
1767 # the trace info. Fall on through.
e22ea7cc 1768 # return;
69893cff
RGS
1769 } ## end if ($runnonstop)
1770
e22ea7cc
RF
1771 elsif ($ImmediateStop) {
1772
1773 # We are supposed to stop here; XXX probably a break.
1774 $ImmediateStop = 0; # We've processed it; turn it off
1775 $signal = 1; # Simulate an interrupt to force
1776 # us into the command loop
69893cff
RGS
1777 }
1778 } ## end if ($single and not $second_time...
1779
1780 # If we're in single-step mode, or an interrupt (real or fake)
1781 # has occurred, turn off non-stop mode.
1782 $runnonstop = 0 if $single or $signal;
1783
1784 # Preserve current values of $@, $!, $^E, $,, $/, $\, $^W.
1785 # The code being debugged may have altered them.
d338d6fe 1786 &save;
69893cff
RGS
1787
1788 # Since DB::DB gets called after every line, we can use caller() to
1789 # figure out where we last were executing. Sneaky, eh? This works because
e22ea7cc 1790 # caller is returning all the extra information when called from the
69893cff 1791 # debugger.
e22ea7cc 1792 local ( $package, $filename, $line ) = caller;
6b24a4b7 1793 $filename_ini = $filename;
69893cff
RGS
1794
1795 # set up the context for DB::eval, so it can properly execute
1796 # code on behalf of the user. We add the package in so that the
1797 # code is eval'ed in the proper package (not in the debugger!).
6b24a4b7 1798 local $usercontext = _calc_usercontext($package);
69893cff
RGS
1799
1800 # Create an alias to the active file magical array to simplify
1801 # the code here.
e22ea7cc 1802 local (*dbline) = $main::{ '_<' . $filename };
aa057b67 1803
69893cff 1804 # Last line in the program.
55783941 1805 $max = $#dbline;
69893cff
RGS
1806
1807 # if we have something here, see if we should break.
e22ea7cc 1808 {
72d7d80d
SF
1809 # $stop is lexical and local to this block - $action on the other hand
1810 # is global.
1811 my $stop;
e22ea7cc 1812
72d7d80d
SF
1813 if ( $dbline{$line}
1814 && _is_breakpoint_enabled($filename, $line)
1815 && (( $stop, $action ) = split( /\0/, $dbline{$line} ) ) )
1816 {
e22ea7cc 1817
72d7d80d
SF
1818 # Stop if the stop criterion says to just stop.
1819 if ( $stop eq '1' ) {
1820 $signal |= 1;
5d5d9ea3 1821 }
72d7d80d
SF
1822
1823 # It's a conditional stop; eval it in the user's context and
1824 # see if we should stop. If so, remove the one-time sigil.
1825 elsif ($stop) {
1826 $evalarg = "\$DB::signal |= 1 if do {$stop}";
1827 &eval;
1828 # If the breakpoint is temporary, then delete its enabled status.
1829 if ($dbline{$line} =~ s/;9($|\0)/$1/) {
1830 _cancel_breakpoint_temp_enabled_status($filename, $line);
1831 }
1832 }
1833 } ## end if ($dbline{$line} && ...
1834 }
69893cff
RGS
1835
1836 # Preserve the current stop-or-not, and see if any of the W
1837 # (watch expressions) has changed.
36477c24 1838 my $was_signal = $signal;
69893cff
RGS
1839
1840 # If we have any watch expressions ...
e22ea7cc 1841 if ( $trace & 2 ) {
2c247e84 1842 for my $n (0 .. $#to_watch) {
e22ea7cc
RF
1843 $evalarg = $to_watch[$n];
1844 local $onetimeDump; # Tell DB::eval() to not output results
69893cff
RGS
1845
1846 # Fix context DB::eval() wants to return an array, but
1847 # we need a scalar here.
e22ea7cc
RF
1848 my ($val) = join( "', '", &eval );
1849 $val = ( ( defined $val ) ? "'$val'" : 'undef' );
69893cff
RGS
1850
1851 # Did it change?
e22ea7cc
RF
1852 if ( $val ne $old_watch[$n] ) {
1853
69893cff 1854 # Yep! Show the difference, and fake an interrupt.
e22ea7cc
RF
1855 $signal = 1;
1856 print $OUT <<EOP;
405ff068 1857Watchpoint $n:\t$to_watch[$n] changed:
69893cff
RGS
1858 old value:\t$old_watch[$n]
1859 new value:\t$val
6027b9a3 1860EOP
e22ea7cc 1861 $old_watch[$n] = $val;
69893cff 1862 } ## end if ($val ne $old_watch...
2c247e84 1863 } ## end for my $n (0 ..
69893cff
RGS
1864 } ## end if ($trace & 2)
1865
1866=head2 C<watchfunction()>
1867
1868C<watchfunction()> is a function that can be defined by the user; it is a
b570d64b 1869function which will be run on each entry to C<DB::DB>; it gets the
69893cff
RGS
1870current package, filename, and line as its parameters.
1871
b570d64b 1872The watchfunction can do anything it likes; it is executing in the
69893cff
RGS
1873debugger's context, so it has access to all of the debugger's internal
1874data structures and functions.
1875
1876C<watchfunction()> can control the debugger's actions. Any of the following
1877will cause the debugger to return control to the user's program after
1878C<watchfunction()> executes:
1879
b570d64b 1880=over 4
69893cff 1881
be9a9b1d
AT
1882=item *
1883
1884Returning a false value from the C<watchfunction()> itself.
1885
1886=item *
1887
1888Altering C<$single> to a false value.
1889
1890=item *
69893cff 1891
be9a9b1d 1892Altering C<$signal> to a false value.
69893cff 1893
be9a9b1d 1894=item *
69893cff 1895
be9a9b1d 1896Turning off the C<4> bit in C<$trace> (this also disables the
69893cff
RGS
1897check for C<watchfunction()>. This can be done with
1898
1899 $trace &= ~4;
1900
1901=back
1902
1903=cut
1904
e22ea7cc 1905 # If there's a user-defined DB::watchfunction, call it with the
69893cff
RGS
1906 # current package, filename, and line. The function executes in
1907 # the DB:: package.
e22ea7cc
RF
1908 if ( $trace & 4 ) { # User-installed watch
1909 return
1910 if watchfunction( $package, $filename, $line )
1911 and not $single
1912 and not $was_signal
1913 and not( $trace & ~4 );
69893cff
RGS
1914 } ## end if ($trace & 4)
1915
e22ea7cc 1916 # Pick up any alteration to $signal in the watchfunction, and
69893cff 1917 # turn off the signal now.
6027b9a3 1918 $was_signal = $signal;
69893cff
RGS
1919 $signal = 0;
1920
1921=head2 GETTING READY TO EXECUTE COMMANDS
1922
1923The debugger decides to take control if single-step mode is on, the
1924C<t> command was entered, or the user generated a signal. If the program
1925has fallen off the end, we set things up so that entering further commands
1926won't cause trouble, and we say that the program is over.
1927
1928=cut
1929
8dc67a69
SF
1930 # Make sure that we always print if asked for explicitly regardless
1931 # of $trace_to_depth .
1932 my $explicit_stop = ($single || $was_signal);
1933
69893cff
RGS
1934 # Check to see if we should grab control ($single true,
1935 # trace set appropriately, or we got a signal).
8dc67a69 1936 if ( $explicit_stop || ( $trace & 1 ) ) {
e22ea7cc 1937
69893cff 1938 # Yes, grab control.
e22ea7cc
RF
1939 if ($slave_editor) {
1940
69893cff 1941 # Tell the editor to update its position.
e22ea7cc
RF
1942 $position = "\032\032$filename:$line:0\n";
1943 print_lineinfo($position);
1944 }
69893cff
RGS
1945
1946=pod
1947
b570d64b 1948Special check: if we're in package C<DB::fake>, we've gone through the
69893cff
RGS
1949C<END> block at least once. We set up everything so that we can continue
1950to enter commands and have a valid context to be in.
1951
1952=cut
1953
e22ea7cc 1954 elsif ( $package eq 'DB::fake' ) {
69893cff 1955
69893cff 1956 # Fallen off the end already.
e22ea7cc
RF
1957 $term || &setterm;
1958 print_help(<<EOP);
405ff068 1959Debugged program terminated. Use B<q> to quit or B<R> to restart,
6b27b0a0 1960 use B<o> I<inhibit_exit> to avoid stopping after program termination,
b570d64b 1961 B<h q>, B<h R> or B<h o> to get additional info.
405ff068 1962EOP
e22ea7cc 1963
69893cff 1964 # Set the DB::eval context appropriately.
e22ea7cc 1965 $package = 'main';
6b24a4b7 1966 $usercontext = _calc_usercontext($package);
69893cff 1967 } ## end elsif ($package eq 'DB::fake')
e219e2fb 1968
69893cff 1969=pod
e219e2fb 1970
69893cff
RGS
1971If the program hasn't finished executing, we scan forward to the
1972next executable line, print that out, build the prompt from the file and line
b570d64b 1973number information, and print that.
e219e2fb 1974
69893cff
RGS
1975=cut
1976
e22ea7cc
RF
1977 else {
1978
8dc67a69 1979
69893cff
RGS
1980 # Still somewhere in the midst of execution. Set up the
1981 # debugger prompt.
1982 $sub =~ s/\'/::/; # Swap Perl 4 package separators (') to
e22ea7cc 1983 # Perl 5 ones (sorry, we don't print Klingon
69893cff
RGS
1984 #module names)
1985
6b24a4b7 1986 $prefix = $sub =~ /::/ ? "" : ($package . '::');
e22ea7cc
RF
1987 $prefix .= "$sub($filename:";
1988 $after = ( $dbline[$line] =~ /\n$/ ? '' : "\n" );
69893cff
RGS
1989
1990 # Break up the prompt if it's really long.
e22ea7cc
RF
1991 if ( length($prefix) > 30 ) {
1992 $position = "$prefix$line):\n$line:\t$dbline[$line]$after";
1993 $prefix = "";
1994 $infix = ":\t";
1995 }
1996 else {
1997 $infix = "):\t";
1998 $position = "$prefix$line$infix$dbline[$line]$after";
1999 }
69893cff
RGS
2000
2001 # Print current line info, indenting if necessary.
e22ea7cc
RF
2002 if ($frame) {
2003 print_lineinfo( ' ' x $stack_depth,
2004 "$line:\t$dbline[$line]$after" );
2005 }
2006 else {
8dc67a69 2007 depth_print_lineinfo($explicit_stop, $position);
e22ea7cc 2008 }
69893cff
RGS
2009
2010 # Scan forward, stopping at either the end or the next
2011 # unbreakable line.
72d7d80d 2012 for ( my $i = $line + 1 ; $i <= $max && $dbline[$i] == 0 ; ++$i )
e22ea7cc 2013 { #{ vi
69893cff
RGS
2014
2015 # Drop out on null statements, block closers, and comments.
2016 last if $dbline[$i] =~ /^\s*[\;\}\#\n]/;
2017
2018 # Drop out if the user interrupted us.
2019 last if $signal;
2020
2021 # Append a newline if the line doesn't have one. Can happen
2022 # in eval'ed text, for instance.
e22ea7cc 2023 $after = ( $dbline[$i] =~ /\n$/ ? '' : "\n" );
69893cff
RGS
2024
2025 # Next executable line.
6b24a4b7 2026 my $incr_pos = "$prefix$i$infix$dbline[$i]$after";
69893cff
RGS
2027 $position .= $incr_pos;
2028 if ($frame) {
e22ea7cc 2029
69893cff 2030 # Print it indented if tracing is on.
e22ea7cc
RF
2031 print_lineinfo( ' ' x $stack_depth,
2032 "$i:\t$dbline[$i]$after" );
69893cff
RGS
2033 }
2034 else {
8dc67a69 2035 depth_print_lineinfo($explicit_stop, $incr_pos);
69893cff 2036 }
72d7d80d 2037 } ## end for ($i = $line + 1 ; $i...
69893cff
RGS
2038 } ## end else [ if ($slave_editor)
2039 } ## end if ($single || ($trace...
2040
2041=pod
2042
2043If there's an action to be executed for the line we stopped at, execute it.
b570d64b 2044If there are any preprompt actions, execute those as well.
e219e2fb
RF
2045
2046=cut
2047
69893cff
RGS
2048 # If there's an action, do it now.
2049 $evalarg = $action, &eval if $action;
e219e2fb 2050
69893cff
RGS
2051 # Are we nested another level (e.g., did we evaluate a function
2052 # that had a breakpoint in it at the debugger prompt)?
e22ea7cc
RF
2053 if ( $single || $was_signal ) {
2054
69893cff 2055 # Yes, go down a level.
e22ea7cc 2056 local $level = $level + 1;
69893cff
RGS
2057
2058 # Do any pre-prompt actions.
e22ea7cc
RF
2059 foreach $evalarg (@$pre) {
2060 &eval;
2061 }
69893cff
RGS
2062
2063 # Complain about too much recursion if we passed the limit.
e22ea7cc 2064 print $OUT $stack_depth . " levels deep in subroutine calls!\n"
69893cff
RGS
2065 if $single & 4;
2066
2067 # The line we're currently on. Set $incr to -1 to stay here
2068 # until we get a command that tells us to advance.
e22ea7cc
RF
2069 $start = $line;
2070 $incr = -1; # for backward motion.
69893cff
RGS
2071
2072 # Tack preprompt debugger actions ahead of any actual input.
e22ea7cc 2073 @typeahead = ( @$pretype, @typeahead );
69893cff
RGS
2074
2075=head2 WHERE ARE WE?
2076
2077XXX Relocate this section?
2078
2079The debugger normally shows the line corresponding to the current line of
2080execution. Sometimes, though, we want to see the next line, or to move elsewhere
2081in the file. This is done via the C<$incr>, C<$start>, and C<$max> variables.
2082
be9a9b1d
AT
2083C<$incr> controls by how many lines the I<current> line should move forward
2084after a command is executed. If set to -1, this indicates that the I<current>
69893cff
RGS
2085line shouldn't change.
2086
be9a9b1d 2087C<$start> is the I<current> line. It is used for things like knowing where to
69893cff
RGS
2088move forwards or backwards from when doing an C<L> or C<-> command.
2089
2090C<$max> tells the debugger where the last line of the current file is. It's
2091used to terminate loops most often.
2092
2093=head2 THE COMMAND LOOP
2094
2095Most of C<DB::DB> is actually a command parsing and dispatch loop. It comes
2096in two parts:
2097
2098=over 4
2099
be9a9b1d
AT
2100=item *
2101
2102The outer part of the loop, starting at the C<CMD> label. This loop
69893cff
RGS
2103reads a command and then executes it.
2104
be9a9b1d
AT
2105=item *
2106
2107The inner part of the loop, starting at the C<PIPE> label. This part
69893cff
RGS
2108is wholly contained inside the C<CMD> block and only executes a command.
2109Used to handle commands running inside a pager.
2110
2111=back
2112
2113So why have two labels to restart the loop? Because sometimes, it's easier to
2114have a command I<generate> another command and then re-execute the loop to do
2115the new command. This is faster, but perhaps a bit more convoluted.
2116
2117=cut
2118
2119 # The big command dispatch loop. It keeps running until the
2120 # user yields up control again.
2121 #
2122 # If we have a terminal for input, and we get something back
2123 # from readline(), keep on processing.
6b24a4b7
SF
2124 my $piped;
2125 my $selected;
2126
e22ea7cc
RF
2127 CMD:
2128 while (
2129
69893cff 2130 # We have a terminal, or can get one ...
e22ea7cc
RF
2131 ( $term || &setterm ),
2132
69893cff 2133 # ... and it belogs to this PID or we get one for this PID ...
e22ea7cc
RF
2134 ( $term_pid == $$ or resetterm(1) ),
2135
69893cff 2136 # ... and we got a line of command input ...
e22ea7cc
RF
2137 defined(
2138 $cmd = &readline(
2cbb2ee1 2139 "$pidprompt $tid DB"
e22ea7cc
RF
2140 . ( '<' x $level )
2141 . ( $#hist + 1 )
2142 . ( '>' x $level ) . " "
69893cff
RGS
2143 )
2144 )
2145 )
2146 {
e22ea7cc 2147
2cbb2ee1 2148 share($cmd);
69893cff
RGS
2149 # ... try to execute the input as debugger commands.
2150
2151 # Don't stop running.
2152 $single = 0;
2153
2154 # No signal is active.
2155 $signal = 0;
2156
2157 # Handle continued commands (ending with \):
3d7a2a93 2158 if ($cmd =~ s/\\\z/\n/) {
e22ea7cc
RF
2159 $cmd .= &readline(" cont: ");
2160 redo CMD;
3d7a2a93 2161 }
69893cff
RGS
2162
2163=head4 The null command
2164
be9a9b1d 2165A newline entered by itself means I<re-execute the last command>. We grab the
69893cff
RGS
2166command out of C<$laststep> (where it was recorded previously), and copy it
2167back into C<$cmd> to be executed below. If there wasn't any previous command,
2168we'll do nothing below (no command will match). If there was, we also save it
2169in the command history and fall through to allow the command parsing to pick
2170it up.
2171
2172=cut
2173
2174 # Empty input means repeat the last command.
e22ea7cc
RF
2175 $cmd =~ /^$/ && ( $cmd = $laststep );
2176 chomp($cmd); # get rid of the annoying extra newline
2177 push( @hist, $cmd ) if length($cmd) > 1;
2178 push( @truehist, $cmd );
2cbb2ee1
RGS
2179 share(@hist);
2180 share(@truehist);
e22ea7cc
RF
2181
2182 # This is a restart point for commands that didn't arrive
2183 # via direct user input. It allows us to 'redo PIPE' to
2184 # re-execute command processing without reading a new command.
69893cff 2185 PIPE: {
e22ea7cc
RF
2186 $cmd =~ s/^\s+//s; # trim annoying leading whitespace
2187 $cmd =~ s/\s+$//s; # trim annoying trailing whitespace
6b24a4b7 2188 my ($i) = split( /\s+/, $cmd );
69893cff
RGS
2189
2190=head3 COMMAND ALIASES
2191
2192The debugger can create aliases for commands (these are stored in the
2193C<%alias> hash). Before a command is executed, the command loop looks it up
2194in the alias hash and substitutes the contents of the alias for the command,
2195completely replacing it.
2196
2197=cut
2198
2199 # See if there's an alias for the command, and set it up if so.
e22ea7cc
RF
2200 if ( $alias{$i} ) {
2201
69893cff
RGS
2202 # Squelch signal handling; we want to keep control here
2203 # if something goes loco during the alias eval.
2204 local $SIG{__DIE__};
2205 local $SIG{__WARN__};
2206
2207 # This is a command, so we eval it in the DEBUGGER's
2208 # scope! Otherwise, we can't see the special debugger
2209 # variables, or get to the debugger's subs. (Well, we
2210 # _could_, but why make it even more complicated?)
2211 eval "\$cmd =~ $alias{$i}";
2212 if ($@) {
2213 local $\ = '';
1f874cb6 2214 print $OUT "Couldn't evaluate '$i' alias: $@";
69893cff
RGS
2215 next CMD;
2216 }
2217 } ## end if ($alias{$i})
2218
2219=head3 MAIN-LINE COMMANDS
2220
2221All of these commands work up to and after the program being debugged has
b570d64b 2222terminated.
69893cff
RGS
2223
2224=head4 C<q> - quit
2225
b570d64b 2226Quit the debugger. This entails setting the C<$fall_off_end> flag, so we don't
69893cff
RGS
2227try to execute further, cleaning any restart-related stuff out of the
2228environment, and executing with the last value of C<$?>.
2229
2230=cut
2231
3d7a2a93 2232 if ($cmd eq 'q') {
69893cff
RGS
2233 $fall_off_end = 1;
2234 clean_ENV();
2235 exit $?;
3d7a2a93 2236 }
69893cff 2237
611272bb 2238=head4 C<t> - trace [n]
69893cff
RGS
2239
2240Turn tracing on or off. Inverts the appropriate bit in C<$trace> (q.v.).
611272bb 2241If level is specified, set C<$trace_to_depth>.
69893cff
RGS
2242
2243=cut
2244
3d7a2a93 2245 if (my ($levels) = $cmd =~ /\At(?:\s+(\d+))?\z/) {
e22ea7cc
RF
2246 $trace ^= 1;
2247 local $\ = '';
611272bb 2248 $trace_to_depth = $levels ? $stack_depth + $levels : 1E9;
e22ea7cc 2249 print $OUT "Trace = "
611272bb
PS
2250 . ( ( $trace & 1 )
2251 ? ( $levels ? "on (to level $trace_to_depth)" : "on" )
2252 : "off" ) . "\n";
e22ea7cc 2253 next CMD;
3d7a2a93 2254 }
69893cff
RGS
2255
2256=head4 C<S> - list subroutines matching/not matching a pattern
2257
2258Walks through C<%sub>, checking to see whether or not to print the name.
2259
2260=cut
2261
826b9a2e
SF
2262 if (my ($print_all_subs, $should_reverse, $Spatt)
2263 = $cmd =~ /\AS(\s+(!)?(.+))?\z/) {
2264 # $Spatt is the pattern (if any) to use.
2265 # Reverse scan?
2266 my $Srev = defined $should_reverse;
2267 # No args - print all subs.
2268 my $Snocheck = !defined $print_all_subs;
69893cff
RGS
2269
2270 # Need to make these sane here.
e22ea7cc
RF
2271 local $\ = '';
2272 local $, = '';
69893cff
RGS
2273
2274 # Search through the debugger's magical hash of subs.
2275 # If $nocheck is true, just print the sub name.
2276 # Otherwise, check it against the pattern. We then use
2277 # the XOR trick to reverse the condition as required.
e22ea7cc
RF
2278 foreach $subname ( sort( keys %sub ) ) {
2279 if ( $Snocheck or $Srev ^ ( $subname =~ /$Spatt/ ) ) {
2280 print $OUT $subname, "\n";
2281 }
2282 }
2283 next CMD;
826b9a2e 2284 }
69893cff
RGS
2285
2286=head4 C<X> - list variables in current package
2287
b570d64b 2288Since the C<V> command actually processes this, just change this to the
69893cff
RGS
2289appropriate C<V> command and fall through.
2290
2291=cut
2292
e22ea7cc 2293 $cmd =~ s/^X\b/V $package/;
69893cff
RGS
2294
2295=head4 C<V> - list variables
2296
b570d64b 2297Uses C<dumpvar.pl> to dump out the current values for selected variables.
69893cff
RGS
2298
2299=cut
2300
2301 # Bare V commands get the currently-being-debugged package
2302 # added.
826b9a2e 2303 if ($cmd eq "V") {
e22ea7cc 2304 $cmd = "V $package";
826b9a2e 2305 }
69893cff
RGS
2306
2307 # V - show variables in package.
826b9a2e
SF
2308 if (my ($new_packname, $new_vars_str) =
2309 $cmd =~ /\AV\b\s*(\S+)\s*(.*)/) {
e22ea7cc 2310
69893cff
RGS
2311 # Save the currently selected filehandle and
2312 # force output to debugger's filehandle (dumpvar
2313 # just does "print" for output).
6b24a4b7 2314 my $savout = select($OUT);
69893cff
RGS
2315
2316 # Grab package name and variables to dump.
826b9a2e
SF
2317 $packname = $new_packname;
2318 my @vars = split( ' ', $new_vars_str );
69893cff
RGS
2319
2320 # If main::dumpvar isn't here, get it.
e81465be 2321 do 'dumpvar.pl' || die $@ unless defined &main::dumpvar;
e22ea7cc
RF
2322 if ( defined &main::dumpvar ) {
2323
69893cff
RGS
2324 # We got it. Turn off subroutine entry/exit messages
2325 # for the moment, along with return values.
e22ea7cc
RF
2326 local $frame = 0;
2327 local $doret = -2;
69893cff
RGS
2328
2329 # must detect sigpipe failures - not catching
2330 # then will cause the debugger to die.
2331 eval {
2332 &main::dumpvar(
2333 $packname,
2334 defined $option{dumpDepth}
e22ea7cc
RF
2335 ? $option{dumpDepth}
2336 : -1, # assume -1 unless specified
69893cff 2337 @vars
e22ea7cc
RF
2338 );
2339 };
2340
2341 # The die doesn't need to include the $@, because
2342 # it will automatically get propagated for us.
2343 if ($@) {
2344 die unless $@ =~ /dumpvar print failed/;
2345 }
2346 } ## end if (defined &main::dumpvar)
2347 else {
2348
2349 # Couldn't load dumpvar.
2350 print $OUT "dumpvar.pl not available.\n";
2351 }
69893cff 2352
69893cff 2353 # Restore the output filehandle, and go round again.
e22ea7cc
RF
2354 select($savout);
2355 next CMD;
826b9a2e 2356 }
69893cff
RGS
2357
2358=head4 C<x> - evaluate and print an expression
2359
2360Hands the expression off to C<DB::eval>, setting it up to print the value
2361via C<dumpvar.pl> instead of just printing it directly.
2362
2363=cut
2364
826b9a2e 2365 if ($cmd =~ s#\Ax\b# #) { # Remainder gets done by DB::eval()
e22ea7cc 2366 $onetimeDump = 'dump'; # main::dumpvar shows the output
69893cff
RGS
2367
2368 # handle special "x 3 blah" syntax XXX propagate
2369 # doc back to special variables.
826b9a2e 2370 if ( $cmd =~ s#\A\s*(\d+)(?=\s)# #) {
e22ea7cc
RF
2371 $onetimedumpDepth = $1;
2372 }
826b9a2e 2373 }
69893cff
RGS
2374
2375=head4 C<m> - print methods
2376
2377Just uses C<DB::methods> to determine what methods are available.
2378
2379=cut
2380
826b9a2e 2381 if ($cmd =~ s#\Am\s+([\w:]+)\s*\z# #) {
e22ea7cc
RF
2382 methods($1);
2383 next CMD;
826b9a2e 2384 }
69893cff
RGS
2385
2386 # m expr - set up DB::eval to do the work
826b9a2e 2387 if ($cmd =~ s#\Am\b# #) { # Rest gets done by DB::eval()
e22ea7cc 2388 $onetimeDump = 'methods'; # method output gets used there
826b9a2e 2389 }
69893cff
RGS
2390
2391=head4 C<f> - switch files
2392
2393=cut
2394
826b9a2e 2395 if (($file) = $cmd =~ /\Af\b\s*(.*)/) {
e22ea7cc 2396 $file =~ s/\s+$//;
69893cff
RGS
2397
2398 # help for no arguments (old-style was return from sub).
e22ea7cc
RF
2399 if ( !$file ) {
2400 print $OUT
2401 "The old f command is now the r command.\n"; # hint
2402 print $OUT "The new f command switches filenames.\n";
2403 next CMD;
2404 } ## end if (!$file)
69893cff
RGS
2405
2406 # if not in magic file list, try a close match.
e22ea7cc
RF
2407 if ( !defined $main::{ '_<' . $file } ) {
2408 if ( ($try) = grep( m#^_<.*$file#, keys %main:: ) ) {
2409 {
2410 $try = substr( $try, 2 );
1f874cb6 2411 print $OUT "Choosing $try matching '$file':\n";
e22ea7cc
RF
2412 $file = $try;
2413 }
2414 } ## end if (($try) = grep(m#^_<.*$file#...
2415 } ## end if (!defined $main::{ ...
69893cff
RGS
2416
2417 # If not successfully switched now, we failed.
e22ea7cc 2418 if ( !defined $main::{ '_<' . $file } ) {
1f874cb6 2419 print $OUT "No file matching '$file' is loaded.\n";
e22ea7cc
RF
2420 next CMD;
2421 }
69893cff 2422
e22ea7cc
RF
2423 # We switched, so switch the debugger internals around.
2424 elsif ( $file ne $filename ) {
2425 *dbline = $main::{ '_<' . $file };
2426 $max = $#dbline;
2427 $filename = $file;
2428 $start = 1;
2429 $cmd = "l";
2430 } ## end elsif ($file ne $filename)
2431
2432 # We didn't switch; say we didn't.
2433 else {
2434 print $OUT "Already in $file.\n";
2435 next CMD;
2436 }
826b9a2e 2437 }
69893cff
RGS
2438
2439=head4 C<.> - return to last-executed line.
2440
2441We set C<$incr> to -1 to indicate that the debugger shouldn't move ahead,
2442and then we look up the line in the magical C<%dbline> hash.
2443
2444=cut
2445
2446 # . command.
826b9a2e 2447 if ($cmd eq '.') {
e22ea7cc 2448 $incr = -1; # stay at current line
69893cff
RGS
2449
2450 # Reset everything to the old location.
e22ea7cc
RF
2451 $start = $line;
2452 $filename = $filename_ini;
2453 *dbline = $main::{ '_<' . $filename };
2454 $max = $#dbline;
69893cff
RGS
2455
2456 # Now where are we?
e22ea7cc
RF
2457 print_lineinfo($position);
2458 next CMD;
826b9a2e 2459 }
69893cff
RGS
2460
2461=head4 C<-> - back one window
2462
2463We change C<$start> to be one window back; if we go back past the first line,
2464we set it to be the first line. We ser C<$incr> to put us back at the
2465currently-executing line, and then put a C<l $start +> (list one window from
2466C<$start>) in C<$cmd> to be executed later.
2467
2468=cut
2469
2470 # - - back a window.
826b9a2e 2471 if ($cmd eq '-') {
e22ea7cc 2472
69893cff 2473 # back up by a window; go to 1 if back too far.
e22ea7cc
RF
2474 $start -= $incr + $window + 1;
2475 $start = 1 if $start <= 0;
2476 $incr = $window - 1;
69893cff
RGS
2477
2478 # Generate and execute a "l +" command (handled below).
e22ea7cc 2479 $cmd = 'l ' . ($start) . '+';
826b9a2e 2480 }
69893cff
RGS
2481
2482=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>, {, {{>
2483
2484In Perl 5.8.0, a realignment of the commands was done to fix up a number of
2485problems, most notably that the default case of several commands destroying
2486the user's work in setting watchpoints, actions, etc. We wanted, however, to
2487retain the old commands for those who were used to using them or who preferred
2488them. At this point, we check for the new commands and call C<cmd_wrapper> to
2489deal with them instead of processing them in-line.
2490
2491=cut
2492
2493 # All of these commands were remapped in perl 5.8.0;
e22ea7cc 2494 # we send them off to the secondary dispatcher (see below).
826b9a2e
SF
2495 if (my ($cmd_letter, $my_arg) = $cmd =~ /\A([aAbBeEhilLMoOPvwW]\b|[<>\{]{1,2})\s*(.*)/so) {
2496 &cmd_wrapper( $cmd_letter, $my_arg, $line );
e22ea7cc 2497 next CMD;
826b9a2e 2498 }
69893cff
RGS
2499
2500=head4 C<y> - List lexicals in higher scope
2501
826b9a2e 2502Uses C<PadWalker> to find the lexicals supplied as arguments in a scope
69893cff
RGS
2503above the current one and then displays then using C<dumpvar.pl>.
2504
2505=cut
2506
826b9a2e
SF
2507 if (my ($match_level, $match_vars)
2508 = $cmd =~ /^y(?:\s+(\d*)\s*(.*))?$/) {
69893cff
RGS
2509
2510 # See if we've got the necessary support.
2511 eval { require PadWalker; PadWalker->VERSION(0.08) }
2512 or &warn(
2513 $@ =~ /locate/
2514 ? "PadWalker module not found - please install\n"
2515 : $@
2516 )
2517 and next CMD;
2518
2519 # Load up dumpvar if we don't have it. If we can, that is.
e81465be 2520 do 'dumpvar.pl' || die $@ unless defined &main::dumpvar;
69893cff
RGS
2521 defined &main::dumpvar
2522 or print $OUT "dumpvar.pl not available.\n"
2523 and next CMD;
2524
2525 # Got all the modules we need. Find them and print them.
826b9a2e 2526 my @vars = split( ' ', $match_vars || '' );
69893cff
RGS
2527
2528 # Find the pad.
826b9a2e 2529 my $h = eval { PadWalker::peek_my( ( $match_level || 0 ) + 1 ) };
69893cff
RGS
2530
2531 # Oops. Can't find it.
2532 $@ and $@ =~ s/ at .*//, &warn($@), next CMD;
2533
2534 # Show the desired vars with dumplex().
2535 my $savout = select($OUT);
2536
2537 # Have dumplex dump the lexicals.
e22ea7cc 2538 dumpvar::dumplex( $_, $h->{$_},
69893cff 2539 defined $option{dumpDepth} ? $option{dumpDepth} : -1,
e22ea7cc
RF
2540 @vars )
2541 for sort keys %$h;
69893cff
RGS
2542 select($savout);
2543 next CMD;
826b9a2e 2544 }
69893cff
RGS
2545
2546=head3 COMMANDS NOT WORKING AFTER PROGRAM ENDS
2547
2548All of the commands below this point don't work after the program being
2549debugged has ended. All of them check to see if the program has ended; this
2550allows the commands to be relocated without worrying about a 'line of
2551demarcation' above which commands can be entered anytime, and below which
2552they can't.
2553
2554=head4 C<n> - single step, but don't trace down into subs
2555
2556Done by setting C<$single> to 2, which forces subs to execute straight through
be9a9b1d 2557when entered (see C<DB::sub>). We also save the C<n> command in C<$laststep>,
826b9a2e 2558so a null command knows what to re-execute.
69893cff
RGS
2559
2560=cut
2561
e22ea7cc 2562 # n - next
826b9a2e 2563 if ($cmd eq 'n') {
69893cff 2564 end_report(), next CMD if $finished and $level <= 1;
e22ea7cc 2565
69893cff
RGS
2566 # Single step, but don't enter subs.
2567 $single = 2;
e22ea7cc 2568
69893cff 2569 # Save for empty command (repeat last).
e22ea7cc
RF
2570 $laststep = $cmd;
2571 last CMD;
826b9a2e 2572 }
69893cff
RGS
2573
2574=head4 C<s> - single-step, entering subs
2575
826b9a2e 2576Sets C<$single> to 1, which causes C<DB::sub> to continue tracing inside
69893cff
RGS
2577subs. Also saves C<s> as C<$lastcmd>.
2578
2579=cut
2580
2581 # s - single step.
826b9a2e 2582 if ($cmd eq 's') {
e22ea7cc 2583
69893cff
RGS
2584 # Get out and restart the command loop if program
2585 # has finished.
e22ea7cc
RF
2586 end_report(), next CMD if $finished and $level <= 1;
2587
69893cff 2588 # Single step should enter subs.
e22ea7cc
RF
2589 $single = 1;
2590
69893cff 2591 # Save for empty command (repeat last).
e22ea7cc
RF
2592 $laststep = $cmd;
2593 last CMD;
826b9a2e 2594 }
69893cff
RGS
2595
2596=head4 C<c> - run continuously, setting an optional breakpoint
2597
2598Most of the code for this command is taken up with locating the optional
2599breakpoint, which is either a subroutine name or a line number. We set
2600the appropriate one-time-break in C<@dbline> and then turn off single-stepping
2601in this and all call levels above this one.
2602
2603=cut
2604
2605 # c - start continuous execution.
ef18ae63 2606 if (($i) = $cmd =~ m#\Ac\b\s*([\w:]*)\s*\z#) {
e22ea7cc 2607
69893cff
RGS
2608 # Hey, show's over. The debugged program finished
2609 # executing already.
2610 end_report(), next CMD if $finished and $level <= 1;
2611
2612 # Capture the place to put a one-time break.
ef18ae63 2613 $subname = $i;
69893cff 2614
e22ea7cc
RF
2615 # Probably not needed, since we finish an interactive
2616 # sub-session anyway...
2617 # local $filename = $filename;
2618 # local *dbline = *dbline; # XXX Would this work?!
69893cff
RGS
2619 #
2620 # The above question wonders if localizing the alias
2621 # to the magic array works or not. Since it's commented
2622 # out, we'll just leave that to speculation for now.
2623
2624 # If the "subname" isn't all digits, we'll assume it
2625 # is a subroutine name, and try to find it.
e22ea7cc
RF
2626 if ( $subname =~ /\D/ ) { # subroutine name
2627 # Qualify it to the current package unless it's
2628 # already qualified.
69893cff
RGS
2629 $subname = $package . "::" . $subname
2630 unless $subname =~ /::/;
e22ea7cc 2631
69893cff
RGS
2632 # find_sub will return "file:line_number" corresponding
2633 # to where the subroutine is defined; we call find_sub,
e22ea7cc 2634 # break up the return value, and assign it in one
69893cff 2635 # operation.
e22ea7cc 2636 ( $file, $i ) = ( find_sub($subname) =~ /^(.*):(.*)$/ );
69893cff
RGS
2637
2638 # Force the line number to be numeric.
e22ea7cc 2639 $i += 0;
69893cff
RGS
2640
2641 # If we got a line number, we found the sub.
e22ea7cc
RF
2642 if ($i) {
2643
69893cff
RGS
2644 # Switch all the debugger's internals around so
2645 # we're actually working with that file.
e22ea7cc
RF
2646 $filename = $file;
2647 *dbline = $main::{ '_<' . $filename };
2648
69893cff 2649 # Mark that there's a breakpoint in this file.
e22ea7cc
RF
2650 $had_breakpoints{$filename} |= 1;
2651
69893cff
RGS
2652 # Scan forward to the first executable line
2653 # after the 'sub whatever' line.
e22ea7cc
RF
2654 $max = $#dbline;
2655 ++$i while $dbline[$i] == 0 && $i < $max;
2656 } ## end if ($i)
69893cff
RGS
2657
2658 # We didn't find a sub by that name.
e22ea7cc
RF
2659 else {
2660 print $OUT "Subroutine $subname not found.\n";
2661 next CMD;
2662 }
2663 } ## end if ($subname =~ /\D/)
69893cff
RGS
2664
2665 # At this point, either the subname was all digits (an
2666 # absolute line-break request) or we've scanned through
2667 # the code following the definition of the sub, looking
2668 # for an executable, which we may or may not have found.
2669 #
2670 # If $i (which we set $subname from) is non-zero, we
e22ea7cc
RF
2671 # got a request to break at some line somewhere. On
2672 # one hand, if there wasn't any real subroutine name
2673 # involved, this will be a request to break in the current
2674 # file at the specified line, so we have to check to make
69893cff
RGS
2675 # sure that the line specified really is breakable.
2676 #
2677 # On the other hand, if there was a subname supplied, the
3c4b39be 2678 # preceding block has moved us to the proper file and
69893cff
RGS
2679 # location within that file, and then scanned forward
2680 # looking for the next executable line. We have to make
2681 # sure that one was found.
2682 #
2683 # On the gripping hand, we can't do anything unless the
2684 # current value of $i points to a valid breakable line.
2685 # Check that.
e22ea7cc
RF
2686 if ($i) {
2687
69893cff 2688 # Breakable?
e22ea7cc
RF
2689 if ( $dbline[$i] == 0 ) {
2690 print $OUT "Line $i not breakable.\n";
2691 next CMD;
2692 }
2693
69893cff 2694 # Yes. Set up the one-time-break sigil.
e22ea7cc 2695 $dbline{$i} =~ s/($|\0)/;9$1/; # add one-time-only b.p.
5d5d9ea3 2696 _enable_breakpoint_temp_enabled_status($filename, $i);
e22ea7cc 2697 } ## end if ($i)
69893cff
RGS
2698
2699 # Turn off stack tracing from here up.
2c247e84
SF
2700 for my $i (0 .. $stack_depth) {
2701 $stack[ $i ] &= ~1;
e22ea7cc
RF
2702 }
2703 last CMD;
ef18ae63 2704 }
69893cff
RGS
2705
2706=head4 C<r> - return from a subroutine
2707
2708For C<r> to work properly, the debugger has to stop execution again
2709immediately after the return is executed. This is done by forcing
2710single-stepping to be on in the call level above the current one. If
2711we are printing return values when a C<r> is executed, set C<$doret>
2712appropriately, and force us out of the command loop.
2713
2714=cut
2715
2716 # r - return from the current subroutine.
ef18ae63 2717 if ($cmd eq 'r') {
e22ea7cc 2718
98dc9551 2719 # Can't do anything if the program's over.
e22ea7cc
RF
2720 end_report(), next CMD if $finished and $level <= 1;
2721
69893cff 2722 # Turn on stack trace.
e22ea7cc
RF
2723 $stack[$stack_depth] |= 1;
2724
69893cff 2725 # Print return value unless the stack is empty.
e22ea7cc
RF
2726 $doret = $option{PrintRet} ? $stack_depth - 1 : -2;
2727 last CMD;
ef18ae63 2728 }
69893cff 2729
69893cff
RGS
2730=head4 C<T> - stack trace
2731
2732Just calls C<DB::print_trace>.
2733
2734=cut
2735
ef18ae63 2736 if ($cmd eq 'T') {
e22ea7cc
RF
2737 print_trace( $OUT, 1 ); # skip DB
2738 next CMD;
ef18ae63 2739 }
69893cff
RGS
2740
2741=head4 C<w> - List window around current line.
2742
2743Just calls C<DB::cmd_w>.
2744
2745=cut
2746
ef18ae63
SF
2747 if (my ($arg) = $cmd =~ /\Aw\b\s*(.*)/s) {
2748 &cmd_w( 'w', $arg );
2749 next CMD;
2750 }
69893cff
RGS
2751
2752=head4 C<W> - watch-expression processing.
2753
b570d64b 2754Just calls C<DB::cmd_W>.
69893cff
RGS
2755
2756=cut
2757
ef18ae63
SF
2758 if (my ($arg) = $cmd =~ /\AW\b\s*(.*)/s) {
2759 &cmd_W( 'W', $arg );
2760 next CMD;
2761 }
69893cff
RGS
2762
2763=head4 C</> - search forward for a string in the source
2764
ef18ae63 2765We take the argument and treat it as a pattern. If it turns out to be a
69893cff 2766bad one, we return the error we got from trying to C<eval> it and exit.
ef18ae63 2767If not, we create some code to do the search and C<eval> it so it can't
69893cff
RGS
2768mess us up.
2769
2770=cut
2771
ef18ae63
SF
2772 # The pattern as a string.
2773 use vars qw($inpat);
69893cff 2774
ef18ae63 2775 if (($inpat) = $cmd =~ m#\A/(.*)\z#) {
69893cff
RGS
2776
2777 # Remove the final slash.
e22ea7cc 2778 $inpat =~ s:([^\\])/$:$1:;
69893cff
RGS
2779
2780 # If the pattern isn't null ...
e22ea7cc 2781 if ( $inpat ne "" ) {
69893cff
RGS
2782
2783 # Turn of warn and die procesing for a bit.
e22ea7cc
RF
2784 local $SIG{__DIE__};
2785 local $SIG{__WARN__};
69893cff
RGS
2786
2787 # Create the pattern.
e22ea7cc
RF
2788 eval '$inpat =~ m' . "\a$inpat\a";
2789 if ( $@ ne "" ) {
2790
69893cff 2791 # Oops. Bad pattern. No biscuit.
e22ea7cc 2792 # Print the eval error and go back for more
69893cff 2793 # commands.
e22ea7cc
RF
2794 print $OUT "$@";
2795 next CMD;
2796 }
2797 $pat = $inpat;
2798 } ## end if ($inpat ne "")
69893cff
RGS
2799
2800 # Set up to stop on wrap-around.
e22ea7cc 2801 $end = $start;
69893cff
RGS
2802
2803 # Don't move off the current line.
e22ea7cc 2804 $incr = -1;
69893cff
RGS
2805
2806 # Done in eval so nothing breaks if the pattern
2807 # does something weird.
e22ea7cc
RF
2808 eval '
2809 for (;;) {
69893cff 2810 # Move ahead one line.
e22ea7cc 2811 ++$start;
69893cff
RGS
2812
2813 # Wrap if we pass the last line.
e22ea7cc 2814 $start = 1 if ($start > $max);
69893cff
RGS
2815
2816 # Stop if we have gotten back to this line again,
e22ea7cc 2817 last if ($start == $end);
69893cff
RGS
2818
2819 # A hit! (Note, though, that we are doing
2820 # case-insensitive matching. Maybe a qr//
2821 # expression would be better, so the user could
2822 # do case-sensitive matching if desired.
e22ea7cc
RF
2823 if ($dbline[$start] =~ m' . "\a$pat\a" . 'i) {
2824 if ($slave_editor) {
69893cff 2825 # Handle proper escaping in the slave.
e22ea7cc 2826 print $OUT "\032\032$filename:$start:0\n";
b570d64b 2827 }
e22ea7cc 2828 else {
69893cff 2829 # Just print the line normally.
e22ea7cc
RF
2830 print $OUT "$start:\t",$dbline[$start],"\n";
2831 }
69893cff 2832 # And quit since we found something.
e22ea7cc
RF
2833 last;
2834 }
2835 } ';
2836
69893cff 2837 # If we wrapped, there never was a match.
e22ea7cc
RF
2838 print $OUT "/$pat/: not found\n" if ( $start == $end );
2839 next CMD;
ef18ae63 2840 }
69893cff
RGS
2841
2842=head4 C<?> - search backward for a string in the source
2843
2844Same as for C</>, except the loop runs backwards.
2845
2846=cut
2847
2848 # ? - backward pattern search.
ef18ae63 2849 if (my ($inpat) = $cmd =~ m#\A\?(.*)\z#) {
69893cff
RGS
2850
2851 # Get the pattern, remove trailing question mark.
e22ea7cc 2852 $inpat =~ s:([^\\])\?$:$1:;
69893cff
RGS
2853
2854 # If we've got one ...
e22ea7cc 2855 if ( $inpat ne "" ) {
69893cff
RGS
2856
2857 # Turn off die & warn handlers.
e22ea7cc
RF
2858 local $SIG{__DIE__};
2859 local $SIG{__WARN__};
2860 eval '$inpat =~ m' . "\a$inpat\a";
2861
2862 if ( $@ ne "" ) {
2863
69893cff 2864 # Ouch. Not good. Print the error.
e22ea7cc
RF
2865 print $OUT $@;
2866 next CMD;
2867 }
2868 $pat = $inpat;
69893cff 2869 } ## end if ($inpat ne "")
e22ea7cc 2870
69893cff 2871 # Where we are now is where to stop after wraparound.
e22ea7cc 2872 $end = $start;
69893cff
RGS
2873
2874 # Don't move away from this line.
e22ea7cc 2875 $incr = -1;
69893cff
RGS
2876
2877 # Search inside the eval to prevent pattern badness
2878 # from killing us.
e22ea7cc
RF
2879 eval '
2880 for (;;) {
69893cff 2881 # Back up a line.
e22ea7cc 2882 --$start;
69893cff
RGS
2883
2884 # Wrap if we pass the first line.
e22ea7cc
RF
2885
2886 $start = $max if ($start <= 0);
69893cff
RGS
2887
2888 # Quit if we get back where we started,
e22ea7cc 2889 last if ($start == $end);
69893cff
RGS
2890
2891 # Match?
e22ea7cc
RF
2892 if ($dbline[$start] =~ m' . "\a$pat\a" . 'i) {
2893 if ($slave_editor) {
69893cff 2894 # Yep, follow slave editor requirements.
e22ea7cc 2895 print $OUT "\032\032$filename:$start:0\n";
b570d64b 2896 }
e22ea7cc 2897 else {
69893cff 2898 # Yep, just print normally.
e22ea7cc
RF
2899 print $OUT "$start:\t",$dbline[$start],"\n";
2900 }
69893cff
RGS
2901
2902 # Found, so done.
e22ea7cc
RF
2903 last;
2904 }
2905 } ';
2906
2907 # Say we failed if the loop never found anything,
2908 print $OUT "?$pat?: not found\n" if ( $start == $end );
2909 next CMD;
ef18ae63 2910 }
69893cff
RGS
2911
2912=head4 C<$rc> - Recall command
2913
2914Manages the commands in C<@hist> (which is created if C<Term::ReadLine> reports
2915that the terminal supports history). It find the the command required, puts it
2916into C<$cmd>, and redoes the loop to execute it.
2917
2918=cut
2919
e22ea7cc 2920 # $rc - recall command.
ef18ae63 2921 if (my ($minus, $arg) = $cmd =~ m#\A$rc+\s*(-)?(\d+)?\z#) {
69893cff
RGS
2922
2923 # No arguments, take one thing off history.
e22ea7cc 2924 pop(@hist) if length($cmd) > 1;
69893cff 2925
e22ea7cc 2926 # Relative (- found)?
69893cff 2927 # Y - index back from most recent (by 1 if bare minus)
e22ea7cc 2928 # N - go to that particular command slot or the last
69893cff 2929 # thing if nothing following.
ef18ae63 2930 $i = $minus ? ( $#hist - ( $arg || 1 ) ) : ( $arg || $#hist );
69893cff
RGS
2931
2932 # Pick out the command desired.
e22ea7cc 2933 $cmd = $hist[$i];
69893cff
RGS
2934
2935 # Print the command to be executed and restart the loop
2936 # with that command in the buffer.
e22ea7cc
RF
2937 print $OUT $cmd, "\n";
2938 redo CMD;
ef18ae63 2939 }
69893cff
RGS
2940
2941=head4 C<$sh$sh> - C<system()> command
2942
2943Calls the C<DB::system()> to handle the command. This keeps the C<STDIN> and
2944C<STDOUT> from getting messed up.
2945
2946=cut
2947
2948 # $sh$sh - run a shell command (if it's all ASCII).
2949 # Can't run shell commands with Unicode in the debugger, hmm.
ef18ae63 2950 if (my ($arg) = $cmd =~ m#\A$sh$sh\s*(.*)#ms) {
e22ea7cc 2951
69893cff 2952 # System it.
ef18ae63 2953 &system($arg);
e22ea7cc 2954 next CMD;
ef18ae63 2955 }
69893cff
RGS
2956
2957=head4 C<$rc I<pattern> $rc> - Search command history
2958
2959Another command to manipulate C<@hist>: this one searches it with a pattern.
be9a9b1d 2960If a command is found, it is placed in C<$cmd> and executed via C<redo>.
69893cff
RGS
2961
2962=cut
2963
e22ea7cc 2964 # $rc pattern $rc - find a command in the history.
ef18ae63 2965 if (my ($arg) = $cmd =~ /\A$rc([^$rc].*)\z/) {
e22ea7cc 2966
69893cff 2967 # Create the pattern to use.
ef18ae63 2968 $pat = "^$arg";
69893cff
RGS
2969
2970 # Toss off last entry if length is >1 (and it always is).
e22ea7cc 2971 pop(@hist) if length($cmd) > 1;
69893cff
RGS
2972
2973 # Look backward through the history.
72d7d80d 2974 for ( $i = $#hist ; $i ; --$i ) {
69893cff 2975 # Stop if we find it.
e22ea7cc
RF
2976 last if $hist[$i] =~ /$pat/;
2977 }
2978
2979 if ( !$i ) {
69893cff 2980
69893cff 2981 # Never found it.
e22ea7cc
RF
2982 print $OUT "No such command!\n\n";
2983 next CMD;
2984 }
69893cff
RGS
2985
2986 # Found it. Put it in the buffer, print it, and process it.
e22ea7cc
RF
2987 $cmd = $hist[$i];
2988 print $OUT $cmd, "\n";
2989 redo CMD;
ef18ae63 2990 }
69893cff 2991
ef18ae63 2992=head4 C<$sh> - Invoke a shell
69893cff
RGS
2993
2994Uses C<DB::system> to invoke a shell.
2995
2996=cut
2997
2998 # $sh - start a shell.
ef18ae63 2999 if ($cmd =~ /\A$sh\z/) {
e22ea7cc 3000
69893cff
RGS
3001 # Run the user's shell. If none defined, run Bourne.
3002 # We resume execution when the shell terminates.
e22ea7cc
RF
3003 &system( $ENV{SHELL} || "/bin/sh" );
3004 next CMD;
ef18ae63 3005 }
69893cff
RGS
3006
3007=head4 C<$sh I<command>> - Force execution of a command in a shell
3008
3009Like the above, but the command is passed to the shell. Again, we use
3010C<DB::system> to avoid problems with C<STDIN> and C<STDOUT>.
3011
3012=cut
3013
3014 # $sh command - start a shell and run a command in it.
ef18ae63 3015 if (my ($arg) = $cmd =~ m#\A$sh\s*(.*)#ms) {
e22ea7cc
RF
3016
3017 # XXX: using csh or tcsh destroys sigint retvals!
3018 #&system($1); # use this instead
69893cff
RGS
3019
3020 # use the user's shell, or Bourne if none defined.
ef18ae63 3021 &system( $ENV{SHELL} || "/bin/sh", "-c", $arg );
e22ea7cc 3022 next CMD;
ef18ae63 3023 }
69893cff
RGS
3024
3025=head4 C<H> - display commands in history
3026
3027Prints the contents of C<@hist> (if any).
3028
3029=cut
3030
ef18ae63 3031 if ($cmd =~ /\AH\b\s*\*/) {
7fddc82f
RF
3032 @hist = @truehist = ();
3033 print $OUT "History cleansed\n";
3034 next CMD;
ef18ae63 3035 }
e22ea7cc 3036
ef18ae63
SF
3037 if (my ($num)
3038 = $cmd =~ /\AH\b\s*(?:-(\d+))?/) {
e22ea7cc
RF
3039
3040 # Anything other than negative numbers is ignored by
69893cff 3041 # the (incorrect) pattern, so this test does nothing.
ef18ae63 3042 $end = $num ? ( $#hist - $num ) : 0;
69893cff
RGS
3043
3044 # Set to the minimum if less than zero.
e22ea7cc 3045 $hist = 0 if $hist < 0;
69893cff 3046
e22ea7cc 3047 # Start at the end of the array.
69893cff
RGS
3048 # Stay in while we're still above the ending value.
3049 # Tick back by one each time around the loop.
72d7d80d 3050 for ( $i = $#hist ; $i > $end ; $i-- ) {
69893cff
RGS
3051
3052 # Print the command unless it has no arguments.
e22ea7cc
RF
3053 print $OUT "$i: ", $hist[$i], "\n"
3054 unless $hist[$i] =~ /^.?$/;
3055 }
3056 next CMD;
ef18ae63 3057 }
69893cff
RGS
3058
3059=head4 C<man, doc, perldoc> - look up documentation
3060
3061Just calls C<runman()> to print the appropriate document.
3062
3063=cut
3064
e22ea7cc 3065 # man, perldoc, doc - show manual pages.
ef18ae63
SF
3066 if (my ($man_page)
3067 = $cmd =~ /\A(?:man|(?:perl)?doc)\b(?:\s+([^(]*))?\z/) {
3068 runman($man_page);
e22ea7cc 3069 next CMD;
ef18ae63 3070 }
69893cff
RGS
3071
3072=head4 C<p> - print
3073
3074Builds a C<print EXPR> expression in the C<$cmd>; this will get executed at
3075the bottom of the loop.
3076
3077=cut
3078
ef18ae63 3079 my $print_cmd = 'print {$DB::OUT} ';
69893cff 3080 # p - print (no args): print $_.
ef18ae63
SF
3081 if ($cmd eq 'p') {
3082 $cmd = $print_cmd . '$_';
3083 }
69893cff
RGS
3084
3085 # p - print the given expression.
ef18ae63 3086 $cmd =~ s/\Ap\b/$print_cmd /;
69893cff
RGS
3087
3088=head4 C<=> - define command alias
3089
3090Manipulates C<%alias> to add or list command aliases.
3091
3092=cut
3093
e22ea7cc 3094 # = - set up a command alias.
ef18ae63 3095 if ($cmd =~ s/\A=\s*//) {
e22ea7cc
RF
3096 my @keys;
3097 if ( length $cmd == 0 ) {
3098
69893cff 3099 # No args, get current aliases.
e22ea7cc
RF
3100 @keys = sort keys %alias;
3101 }
3102 elsif ( my ( $k, $v ) = ( $cmd =~ /^(\S+)\s+(\S.*)/ ) ) {
3103
69893cff
RGS
3104 # Creating a new alias. $k is alias name, $v is
3105 # alias value.
3106
e22ea7cc
RF
3107 # can't use $_ or kill //g state
3108 for my $x ( $k, $v ) {
3109
3110 # Escape "alarm" characters.
3111 $x =~ s/\a/\\a/g;
3112 }
69893cff
RGS
3113
3114 # Substitute key for value, using alarm chars
e22ea7cc 3115 # as separators (which is why we escaped them in
69893cff 3116 # the command).
e22ea7cc 3117 $alias{$k} = "s\a$k\a$v\a";
69893cff
RGS
3118
3119 # Turn off standard warn and die behavior.
e22ea7cc
RF
3120 local $SIG{__DIE__};
3121 local $SIG{__WARN__};
69893cff
RGS
3122
3123 # Is it valid Perl?
e22ea7cc
RF
3124 unless ( eval "sub { s\a$k\a$v\a }; 1" ) {
3125
69893cff 3126 # Nope. Bad alias. Say so and get out.
e22ea7cc
RF
3127 print $OUT "Can't alias $k to $v: $@\n";
3128 delete $alias{$k};
3129 next CMD;
3130 }
3131
69893cff 3132 # We'll only list the new one.
e22ea7cc 3133 @keys = ($k);
69893cff
RGS
3134 } ## end elsif (my ($k, $v) = ($cmd...
3135
3136 # The argument is the alias to list.
e22ea7cc
RF
3137 else {
3138 @keys = ($cmd);
3139 }
69893cff
RGS
3140
3141 # List aliases.
e22ea7cc
RF
3142 for my $k (@keys) {
3143
98dc9551 3144 # Messy metaquoting: Trim the substitution code off.
69893cff
RGS
3145 # We use control-G as the delimiter because it's not
3146 # likely to appear in the alias.
e22ea7cc
RF
3147 if ( ( my $v = $alias{$k} ) =~ s\as\a$k\a(.*)\a$\a1\a ) {
3148
69893cff 3149 # Print the alias.
e22ea7cc
RF
3150 print $OUT "$k\t= $1\n";
3151 }
3152 elsif ( defined $alias{$k} ) {
3153
69893cff 3154 # Couldn't trim it off; just print the alias code.
e22ea7cc
RF
3155 print $OUT "$k\t$alias{$k}\n";
3156 }
3157 else {
3158
69893cff 3159 # No such, dude.
e22ea7cc
RF
3160 print "No alias for $k\n";
3161 }
69893cff 3162 } ## end for my $k (@keys)
e22ea7cc 3163 next CMD;
ef18ae63 3164 }
69893cff
RGS
3165
3166=head4 C<source> - read commands from a file.
3167
3168Opens a lexical filehandle and stacks it on C<@cmdfhs>; C<DB::readline> will
3169pick it up.
3170
3171=cut
3172
e22ea7cc 3173 # source - read commands from a file (or pipe!) and execute.
ef18ae63
SF
3174 if (my ($sourced_fn) = $cmd =~ /\Asource\s+(.*\S)/) {
3175 if ( open my $fh, $sourced_fn ) {
e22ea7cc 3176
69893cff 3177 # Opened OK; stick it in the list of file handles.
e22ea7cc
RF
3178 push @cmdfhs, $fh;
3179 }
3180 else {
3181
3182 # Couldn't open it.
ef18ae63 3183 &warn("Can't execute '$sourced_fn': $!\n");
e22ea7cc
RF
3184 }
3185 next CMD;
ef18ae63 3186 }
69893cff 3187
ef18ae63
SF
3188 if (my ($which_cmd, $position)
3189 = $cmd =~ /^(enable|disable)\s+(\S+)\s*$/) {
e09195af
SF
3190
3191 my ($fn, $line_num);
3192 if ($position =~ m{\A\d+\z})
3193 {
3194 $fn = $filename;
3195 $line_num = $position;
3196 }
ef18ae63
SF
3197 elsif (my ($new_fn, $new_line_num)
3198 = $position =~ m{\A(.*):(\d+)\z}) {
3199 ($fn, $line_num) = ($new_fn, $new_line_num);
e09195af
SF
3200 }
3201 else
3202 {
3203 &warn("Wrong spec for enable/disable argument.\n");
3204 }
3205
3206 if (defined($fn)) {
3207 if (_has_breakpoint_data_ref($fn, $line_num)) {
3208 _set_breakpoint_enabled_status($fn, $line_num,
ef18ae63 3209 ($which_cmd eq 'enable' ? 1 : '')
e09195af
SF
3210 );
3211 }
3212 else {
3213 &warn("No breakpoint set at ${fn}:${line_num}\n");
3214 }
3215 }
3216
3217 next CMD;
ef18ae63 3218 }
e09195af 3219
69893cff
RGS
3220=head4 C<save> - send current history to a file
3221
3222Takes the complete history, (not the shrunken version you see with C<H>),
3223and saves it to the given filename, so it can be replayed using C<source>.
3224
3225Note that all C<^(save|source)>'s are commented out with a view to minimise recursion.
3226
3227=cut
3228
3229 # save source - write commands to a file for later use
ef18ae63
SF
3230 if (my ($new_fn) = $cmd =~ /\Asave\s*(.*)\z/) {
3231 my $filename = $new_fn || '.perl5dbrc'; # default?
3232 if ( open my $fh, '>', $filename ) {
e22ea7cc
RF
3233
3234 # chomp to remove extraneous newlines from source'd files
3235 chomp( my @truelist =
3236 map { m/^\s*(save|source)/ ? "#$_" : $_ }
3237 @truehist );
3238 print $fh join( "\n", @truelist );
69893cff 3239 print "commands saved in $file\n";
e22ea7cc
RF
3240 }
3241 else {
ef18ae63 3242 &warn("Can't save debugger commands in '$new_fn': $!\n");
69893cff
RGS
3243 }
3244 next CMD;
ef18ae63 3245 }
69893cff 3246
7fddc82f
RF
3247=head4 C<R> - restart
3248
ef18ae63 3249Restart the debugger session.
7fddc82f
RF
3250
3251=head4 C<rerun> - rerun the current session
3252
3253Return to any given position in the B<true>-history list
3254
3255=cut
3256
3257 # R - restart execution.
3258 # rerun - controlled restart execution.
ff41e38d
SF
3259 if (my ($cmd_cmd, $cmd_params) =
3260 $cmd =~ /\A((?:R)|(?:rerun\s*(.*)))\z/) {
3261 my @args = ($cmd_cmd eq 'R' ? restart() : rerun($cmd_params));
7fddc82f 3262
ca28b541
AP
3263 # Close all non-system fds for a clean restart. A more
3264 # correct method would be to close all fds that were not
3265 # open when the process started, but this seems to be
3266 # hard. See "debugger 'R'estart and open database
3267 # connections" on p5p.
3268
47d3bbda 3269 my $max_fd = 1024; # default if POSIX can't be loaded
ca28b541 3270 if (eval { require POSIX }) {
5332cc68 3271 eval { $max_fd = POSIX::sysconf(POSIX::_SC_OPEN_MAX()) };
ca28b541
AP
3272 }
3273
3274 if (defined $max_fd) {
3275 foreach ($^F+1 .. $max_fd-1) {
3276 next unless open FD_TO_CLOSE, "<&=$_";
3277 close(FD_TO_CLOSE);
3278 }
3279 }
3280
7fddc82f
RF
3281 # And run Perl again. We use exec() to keep the
3282 # PID stable (and that way $ini_pids is still valid).
3283 exec(@args) || print $OUT "exec failed: $!\n";
3284
3285 last CMD;
ff41e38d 3286 }
7fddc82f 3287
69893cff
RGS
3288=head4 C<|, ||> - pipe output through the pager.
3289
be9a9b1d 3290For C<|>, we save C<OUT> (the debugger's output filehandle) and C<STDOUT>
69893cff
RGS
3291(the program's standard output). For C<||>, we only save C<OUT>. We open a
3292pipe to the pager (restoring the output filehandles if this fails). If this
b570d64b 3293is the C<|> command, we also set up a C<SIGPIPE> handler which will simply
69893cff
RGS
3294set C<$signal>, sending us back into the debugger.
3295
3296We then trim off the pipe symbols and C<redo> the command loop at the
3297C<PIPE> label, causing us to evaluate the command in C<$cmd> without
3298reading another.
3299
3300=cut
3301
3302 # || - run command in the pager, with output to DB::OUT.
ff41e38d 3303 if ($cmd =~ m#\A\|\|?\s*[^|]#) {
e22ea7cc
RF
3304 if ( $pager =~ /^\|/ ) {
3305
69893cff 3306 # Default pager is into a pipe. Redirect I/O.
e22ea7cc
RF
3307 open( SAVEOUT, ">&STDOUT" )
3308 || &warn("Can't save STDOUT");
3309 open( STDOUT, ">&OUT" )
3310 || &warn("Can't redirect STDOUT");
69893cff 3311 } ## end if ($pager =~ /^\|/)
e22ea7cc
RF
3312 else {
3313
69893cff 3314 # Not into a pipe. STDOUT is safe.
e22ea7cc
RF
3315 open( SAVEOUT, ">&OUT" ) || &warn("Can't save DB::OUT");
3316 }
69893cff
RGS
3317
3318 # Fix up environment to record we have less if so.
e22ea7cc
RF
3319 fix_less();
3320
3321 unless ( $piped = open( OUT, $pager ) ) {
69893cff 3322
69893cff 3323 # Couldn't open pipe to pager.
1f874cb6 3324 &warn("Can't pipe output to '$pager'");
e22ea7cc
RF
3325 if ( $pager =~ /^\|/ ) {
3326
69893cff 3327 # Redirect I/O back again.
e22ea7cc
RF
3328 open( OUT, ">&STDOUT" ) # XXX: lost message
3329 || &warn("Can't restore DB::OUT");
3330 open( STDOUT, ">&SAVEOUT" )
3331 || &warn("Can't restore STDOUT");
3332 close(SAVEOUT);
69893cff 3333 } ## end if ($pager =~ /^\|/)
e22ea7cc
RF
3334 else {
3335
69893cff 3336 # Redirect I/O. STDOUT already safe.
e22ea7cc
RF
3337 open( OUT, ">&STDOUT" ) # XXX: lost message
3338 || &warn("Can't restore DB::OUT");
3339 }
3340 next CMD;
69893cff
RGS
3341 } ## end unless ($piped = open(OUT,...
3342
3343 # Set up broken-pipe handler if necessary.
e22ea7cc
RF
3344 $SIG{PIPE} = \&DB::catch
3345 if $pager =~ /^\|/
3346 && ( "" eq $SIG{PIPE} || "DEFAULT" eq $SIG{PIPE} );
69893cff 3347
70c9432b
SF
3348 OUT->autoflush(1);
3349 # Save current filehandle, and put it back.
e22ea7cc 3350 $selected = select(OUT);
69893cff 3351 # Don't put it back if pager was a pipe.
e22ea7cc 3352 select($selected), $selected = "" unless $cmd =~ /^\|\|/;
69893cff
RGS
3353
3354 # Trim off the pipe symbols and run the command now.
ff41e38d 3355 $cmd =~ s#\A\|+\s*##;
e22ea7cc 3356 redo PIPE;
ff41e38d 3357 }
69893cff
RGS
3358
3359=head3 END OF COMMAND PARSING
3360
ff41e38d
SF
3361Anything left in C<$cmd> at this point is a Perl expression that we want to
3362evaluate. We'll always evaluate in the user's context, and fully qualify
69893cff
RGS
3363any variables we might want to address in the C<DB> package.
3364
3365=cut
3366
3367 # t - turn trace on.
ff41e38d
SF
3368 if ($cmd =~ s#\At\s+(\d+)?#\$DB::trace |= 1;\n#) {
3369 my $trace_arg = $1;
3370 $trace_to_depth = $trace_arg ? $stack_depth||0 + $1 : 1E9;
3371 }
69893cff
RGS
3372
3373 # s - single-step. Remember the last command was 's'.
ff41e38d
SF
3374 if ($cmd =~ s/\As\s/\$DB::single = 1;\n/) {
3375 $laststep = 's';
3376 }
69893cff
RGS
3377
3378 # n - single-step, but not into subs. Remember last command
e22ea7cc 3379 # was 'n'.
ff41e38d
SF
3380 if ($cmd =~ s#\An\s#\$DB::single = 2;\n#) {
3381 $laststep = 'n';
3382 }
69893cff 3383
e22ea7cc 3384 } # PIPE:
69893cff 3385
e22ea7cc 3386 # Make sure the flag that says "the debugger's running" is
69893cff 3387 # still on, to make sure we get control again.
e22ea7cc 3388 $evalarg = "\$^D = \$^D | \$DB::db_stop;\n$cmd";
69893cff
RGS
3389
3390 # Run *our* eval that executes in the caller's context.
e22ea7cc 3391 &eval;
69893cff
RGS
3392
3393 # Turn off the one-time-dump stuff now.
e22ea7cc
RF
3394 if ($onetimeDump) {
3395 $onetimeDump = undef;
69893cff 3396 $onetimedumpDepth = undef;
e22ea7cc
RF
3397 }
3398 elsif ( $term_pid == $$ ) {
c7e68384
IZ
3399 eval { # May run under miniperl, when not available...
3400 STDOUT->flush();
3401 STDERR->flush();
3402 };
e22ea7cc 3403
69893cff 3404 # XXX If this is the master pid, print a newline.
e22ea7cc
RF
3405 print $OUT "\n";
3406 }
3407 } ## end while (($term || &setterm...
69893cff
RGS
3408
3409=head3 POST-COMMAND PROCESSING
3410
3411After each command, we check to see if the command output was piped anywhere.
3412If so, we go through the necessary code to unhook the pipe and go back to
3413our standard filehandles for input and output.
3414
3415=cut
3416
e22ea7cc 3417 continue { # CMD:
69893cff
RGS
3418
3419 # At the end of every command:
e22ea7cc
RF
3420 if ($piped) {
3421
69893cff 3422 # Unhook the pipe mechanism now.
e22ea7cc
RF
3423 if ( $pager =~ /^\|/ ) {
3424
69893cff 3425 # No error from the child.
e22ea7cc 3426 $? = 0;
69893cff 3427
e22ea7cc
RF
3428 # we cannot warn here: the handle is missing --tchrist
3429 close(OUT) || print SAVEOUT "\nCan't close DB::OUT\n";
69893cff 3430
e22ea7cc 3431 # most of the $? crud was coping with broken cshisms
69893cff 3432 # $? is explicitly set to 0, so this never runs.
e22ea7cc 3433 if ($?) {
1f874cb6 3434 print SAVEOUT "Pager '$pager' failed: ";
e22ea7cc
RF
3435 if ( $? == -1 ) {
3436 print SAVEOUT "shell returned -1\n";
3437 }
3438 elsif ( $? >> 8 ) {
3439 print SAVEOUT ( $? & 127 )
3440 ? " (SIG#" . ( $? & 127 ) . ")"
3441 : "", ( $? & 128 ) ? " -- core dumped" : "", "\n";
3442 }
3443 else {
3444 print SAVEOUT "status ", ( $? >> 8 ), "\n";
3445 }
69893cff
RGS
3446 } ## end if ($?)
3447
e22ea7cc 3448 # Reopen filehandle for our output (if we can) and
69893cff 3449 # restore STDOUT (if we can).
e22ea7cc
RF
3450 open( OUT, ">&STDOUT" ) || &warn("Can't restore DB::OUT");
3451 open( STDOUT, ">&SAVEOUT" )
3452 || &warn("Can't restore STDOUT");
69893cff
RGS
3453
3454 # Turn off pipe exception handler if necessary.
e22ea7cc 3455 $SIG{PIPE} = "DEFAULT" if $SIG{PIPE} eq \&DB::catch;
69893cff 3456
e22ea7cc
RF
3457 # Will stop ignoring SIGPIPE if done like nohup(1)
3458 # does SIGINT but Perl doesn't give us a choice.
69893cff 3459 } ## end if ($pager =~ /^\|/)
e22ea7cc
RF
3460 else {
3461
69893cff 3462 # Non-piped "pager". Just restore STDOUT.
e22ea7cc
RF
3463 open( OUT, ">&SAVEOUT" ) || &warn("Can't restore DB::OUT");
3464 }
69893cff
RGS
3465
3466 # Close filehandle pager was using, restore the normal one
3467 # if necessary,
3468 close(SAVEOUT);
e22ea7cc 3469 select($selected), $selected = "" unless $selected eq "";
69893cff
RGS
3470
3471 # No pipes now.
e22ea7cc 3472 $piped = "";
69893cff 3473 } ## end if ($piped)
e22ea7cc 3474 } # CMD:
69893cff
RGS
3475
3476=head3 COMMAND LOOP TERMINATION
3477
3478When commands have finished executing, we come here. If the user closed the
3479input filehandle, we turn on C<$fall_off_end> to emulate a C<q> command. We
3480evaluate any post-prompt items. We restore C<$@>, C<$!>, C<$^E>, C<$,>, C<$/>,
3481C<$\>, and C<$^W>, and return a null list as expected by the Perl interpreter.
3482The interpreter will then execute the next line and then return control to us
3483again.
3484
3485=cut
3486
3487 # No more commands? Quit.
1f874cb6 3488 $fall_off_end = 1 unless defined $cmd; # Emulate 'q' on EOF
69893cff
RGS
3489
3490 # Evaluate post-prompt commands.
e22ea7cc
RF
3491 foreach $evalarg (@$post) {
3492 &eval;
3493 }
3494 } # if ($single || $signal)
69893cff
RGS
3495
3496 # Put the user's globals back where you found them.
e22ea7cc 3497 ( $@, $!, $^E, $,, $/, $\, $^W ) = @saved;
69893cff
RGS
3498 ();
3499} ## end sub DB
3500
3501# The following code may be executed now:
3502# BEGIN {warn 4}
3503
3504=head2 sub
3505
b570d64b 3506C<sub> is called whenever a subroutine call happens in the program being
69893cff
RGS
3507debugged. The variable C<$DB::sub> contains the name of the subroutine
3508being called.
3509
3510The core function of this subroutine is to actually call the sub in the proper
3511context, capturing its output. This of course causes C<DB::DB> to get called
3512again, repeating until the subroutine ends and returns control to C<DB::sub>
3513again. Once control returns, C<DB::sub> figures out whether or not to dump the
3514return value, and returns its captured copy of the return value as its own
3515return value. The value then feeds back into the program being debugged as if
3516C<DB::sub> hadn't been there at all.
3517
3518C<sub> does all the work of printing the subroutine entry and exit messages
3519enabled by setting C<$frame>. It notes what sub the autoloader got called for,
b570d64b 3520and also prints the return value if needed (for the C<r> command and if
69893cff
RGS
3521the 16 bit is set in C<$frame>).
3522
3523It also tracks the subroutine call depth by saving the current setting of
3524C<$single> in the C<@stack> package global; if this exceeds the value in
3525C<$deep>, C<sub> automatically turns on printing of the current depth by
be9a9b1d 3526setting the C<4> bit in C<$single>. In any case, it keeps the current setting
69893cff
RGS
3527of stop/don't stop on entry to subs set as it currently is set.
3528
3529=head3 C<caller()> support
3530
3531If C<caller()> is called from the package C<DB>, it provides some
3532additional data, in the following order:
3533
3534=over 4
3535
3536=item * C<$package>
3537
3538The package name the sub was in
3539
3540=item * C<$filename>
3541
3542The filename it was defined in
3543
3544=item * C<$line>
3545
3546The line number it was defined on
3547
3548=item * C<$subroutine>
3549
be9a9b1d 3550The subroutine name; C<(eval)> if an C<eval>().