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[perl5db-refactor] convert to use vars and &s.
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e22ea7cc 1
b570d64b 2=head1 NAME
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be9a9b1d 4perl5db.pl - the perl debugger
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5
6=head1 SYNOPSIS
7
8 perl -d your_Perl_script
9
10=head1 DESCRIPTION
11
12C<perl5db.pl> is the perl debugger. It is loaded automatically by Perl when
13you invoke a script with C<perl -d>. This documentation tries to outline the
14structure and services provided by C<perl5db.pl>, and to describe how you
15can use them.
16
17=head1 GENERAL NOTES
18
19The debugger can look pretty forbidding to many Perl programmers. There are
20a number of reasons for this, many stemming out of the debugger's history.
21
22When the debugger was first written, Perl didn't have a lot of its nicer
23features - no references, no lexical variables, no closures, no object-oriented
24programming. So a lot of the things one would normally have done using such
b570d64b 25features was done using global variables, globs and the C<local()> operator
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26in creative ways.
27
28Some of these have survived into the current debugger; a few of the more
29interesting and still-useful idioms are noted in this section, along with notes
30on the comments themselves.
31
32=head2 Why not use more lexicals?
33
34Experienced Perl programmers will note that the debugger code tends to use
35mostly package globals rather than lexically-scoped variables. This is done
36to allow a significant amount of control of the debugger from outside the
b570d64b 37debugger itself.
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38
39Unfortunately, though the variables are accessible, they're not well
40documented, so it's generally been a decision that hasn't made a lot of
41difference to most users. Where appropriate, comments have been added to
42make variables more accessible and usable, with the understanding that these
be9a9b1d 43I<are> debugger internals, and are therefore subject to change. Future
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44development should probably attempt to replace the globals with a well-defined
45API, but for now, the variables are what we've got.
46
47=head2 Automated variable stacking via C<local()>
48
b570d64b 49As you may recall from reading C<perlfunc>, the C<local()> operator makes a
69893cff 50temporary copy of a variable in the current scope. When the scope ends, the
b570d64b 51old copy is restored. This is often used in the debugger to handle the
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52automatic stacking of variables during recursive calls:
53
54 sub foo {
55 local $some_global++;
56
57 # Do some stuff, then ...
58 return;
59 }
60
61What happens is that on entry to the subroutine, C<$some_global> is localized,
b570d64b 62then altered. When the subroutine returns, Perl automatically undoes the
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63localization, restoring the previous value. Voila, automatic stack management.
64
b570d64b 65The debugger uses this trick a I<lot>. Of particular note is C<DB::eval>,
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66which lets the debugger get control inside of C<eval>'ed code. The debugger
67localizes a saved copy of C<$@> inside the subroutine, which allows it to
68keep C<$@> safe until it C<DB::eval> returns, at which point the previous
b570d64b 69value of C<$@> is restored. This makes it simple (well, I<simpler>) to keep
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70track of C<$@> inside C<eval>s which C<eval> other C<eval's>.
71
72In any case, watch for this pattern. It occurs fairly often.
73
74=head2 The C<^> trick
75
b570d64b 76This is used to cleverly reverse the sense of a logical test depending on
69893cff 77the value of an auxiliary variable. For instance, the debugger's C<S>
b570d64b 78(search for subroutines by pattern) allows you to negate the pattern
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79like this:
80
81 # Find all non-'foo' subs:
b570d64b 82 S !/foo/
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83
84Boolean algebra states that the truth table for XOR looks like this:
85
86=over 4
87
b570d64b 88=item * 0 ^ 0 = 0
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89
90(! not present and no match) --> false, don't print
91
b570d64b 92=item * 0 ^ 1 = 1
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93
94(! not present and matches) --> true, print
95
b570d64b 96=item * 1 ^ 0 = 1
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97
98(! present and no match) --> true, print
99
b570d64b 100=item * 1 ^ 1 = 0
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101
102(! present and matches) --> false, don't print
103
104=back
105
106As you can see, the first pair applies when C<!> isn't supplied, and
be9a9b1d 107the second pair applies when it is. The XOR simply allows us to
b570d64b 108compact a more complicated if-then-elseif-else into a more elegant
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109(but perhaps overly clever) single test. After all, it needed this
110explanation...
111
112=head2 FLAGS, FLAGS, FLAGS
113
114There is a certain C programming legacy in the debugger. Some variables,
be9a9b1d 115such as C<$single>, C<$trace>, and C<$frame>, have I<magical> values composed
69893cff 116of 1, 2, 4, etc. (powers of 2) OR'ed together. This allows several pieces
b570d64b 117of state to be stored independently in a single scalar.
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118
119A test like
120
121 if ($scalar & 4) ...
122
b570d64b 123is checking to see if the appropriate bit is on. Since each bit can be
69893cff 124"addressed" independently in this way, C<$scalar> is acting sort of like
b570d64b 125an array of bits. Obviously, since the contents of C<$scalar> are just a
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126bit-pattern, we can save and restore it easily (it will just look like
127a number).
128
129The problem, is of course, that this tends to leave magic numbers scattered
b570d64b 130all over your program whenever a bit is set, cleared, or checked. So why do
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131it?
132
133=over 4
134
be9a9b1d 135=item *
69893cff 136
be9a9b1d 137First, doing an arithmetical or bitwise operation on a scalar is
69893cff 138just about the fastest thing you can do in Perl: C<use constant> actually
be9a9b1d 139creates a subroutine call, and array and hash lookups are much slower. Is
b570d64b 140this over-optimization at the expense of readability? Possibly, but the
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141debugger accesses these variables a I<lot>. Any rewrite of the code will
142probably have to benchmark alternate implementations and see which is the
b570d64b 143best balance of readability and speed, and then document how it actually
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144works.
145
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146=item *
147
b570d64b 148Second, it's very easy to serialize a scalar number. This is done in
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149the restart code; the debugger state variables are saved in C<%ENV> and then
150restored when the debugger is restarted. Having them be just numbers makes
b570d64b 151this trivial.
69893cff 152
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153=item *
154
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155Third, some of these variables are being shared with the Perl core
156smack in the middle of the interpreter's execution loop. It's much faster for
157a C program (like the interpreter) to check a bit in a scalar than to access
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158several different variables (or a Perl array).
159
160=back
161
162=head2 What are those C<XXX> comments for?
163
164Any comment containing C<XXX> means that the comment is either somewhat
b570d64b 165speculative - it's not exactly clear what a given variable or chunk of
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166code is doing, or that it is incomplete - the basics may be clear, but the
167subtleties are not completely documented.
168
169Send in a patch if you can clear up, fill out, or clarify an C<XXX>.
170
b570d64b 171=head1 DATA STRUCTURES MAINTAINED BY CORE
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172
173There are a number of special data structures provided to the debugger by
174the Perl interpreter.
175
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176The array C<@{$main::{'_<'.$filename}}> (aliased locally to C<@dbline>
177via glob assignment) contains the text from C<$filename>, with each
178element corresponding to a single line of C<$filename>. Additionally,
179breakable lines will be dualvars with the numeric component being the
180memory address of a COP node. Non-breakable lines are dualvar to 0.
69893cff 181
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182The hash C<%{'_<'.$filename}> (aliased locally to C<%dbline> via glob
183assignment) contains breakpoints and actions. The keys are line numbers;
184you can set individual values, but not the whole hash. The Perl interpreter
69893cff 185uses this hash to determine where breakpoints have been set. Any true value is
be9a9b1d 186considered to be a breakpoint; C<perl5db.pl> uses C<$break_condition\0$action>.
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187Values are magical in numeric context: 1 if the line is breakable, 0 if not.
188
ef18ae63 189The scalar C<${"_<$filename"}> simply contains the string C<<< _<$filename> >>>.
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190This is also the case for evaluated strings that contain subroutines, or
191which are currently being executed. The $filename for C<eval>ed strings looks
d24ca0c5 192like C<(eval 34).
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193
194=head1 DEBUGGER STARTUP
195
196When C<perl5db.pl> starts, it reads an rcfile (C<perl5db.ini> for
197non-interactive sessions, C<.perldb> for interactive ones) that can set a number
198of options. In addition, this file may define a subroutine C<&afterinit>
b570d64b 199that will be executed (in the debugger's context) after the debugger has
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200initialized itself.
201
b570d64b 202Next, it checks the C<PERLDB_OPTS> environment variable and treats its
be9a9b1d 203contents as the argument of a C<o> command in the debugger.
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204
205=head2 STARTUP-ONLY OPTIONS
206
207The following options can only be specified at startup.
208To set them in your rcfile, add a call to
209C<&parse_options("optionName=new_value")>.
210
211=over 4
212
b570d64b 213=item * TTY
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214
215the TTY to use for debugging i/o.
216
b570d64b 217=item * noTTY
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218
219if set, goes in NonStop mode. On interrupt, if TTY is not set,
b0e77abc 220uses the value of noTTY or F<$HOME/.perldbtty$$> to find TTY using
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221Term::Rendezvous. Current variant is to have the name of TTY in this
222file.
223
b570d64b 224=item * ReadLine
69893cff 225
5561b870 226if false, a dummy ReadLine is used, so you can debug
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227ReadLine applications.
228
b570d64b 229=item * NonStop
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230
231if true, no i/o is performed until interrupt.
232
b570d64b 233=item * LineInfo
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234
235file or pipe to print line number info to. If it is a
236pipe, a short "emacs like" message is used.
237
b570d64b 238=item * RemotePort
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239
240host:port to connect to on remote host for remote debugging.
241
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242=item * HistFile
243
244file to store session history to. There is no default and so no
245history file is written unless this variable is explicitly set.
246
247=item * HistSize
248
249number of commands to store to the file specified in C<HistFile>.
250Default is 100.
251
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252=back
253
254=head3 SAMPLE RCFILE
255
256 &parse_options("NonStop=1 LineInfo=db.out");
257 sub afterinit { $trace = 1; }
258
259The script will run without human intervention, putting trace
260information into C<db.out>. (If you interrupt it, you had better
be9a9b1d 261reset C<LineInfo> to something I<interactive>!)
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262
263=head1 INTERNALS DESCRIPTION
264
265=head2 DEBUGGER INTERFACE VARIABLES
266
267Perl supplies the values for C<%sub>. It effectively inserts
be9a9b1d 268a C<&DB::DB();> in front of each place that can have a
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269breakpoint. At each subroutine call, it calls C<&DB::sub> with
270C<$DB::sub> set to the called subroutine. It also inserts a C<BEGIN
271{require 'perl5db.pl'}> before the first line.
272
273After each C<require>d file is compiled, but before it is executed, a
274call to C<&DB::postponed($main::{'_<'.$filename})> is done. C<$filename>
275is the expanded name of the C<require>d file (as found via C<%INC>).
276
277=head3 IMPORTANT INTERNAL VARIABLES
278
279=head4 C<$CreateTTY>
280
281Used to control when the debugger will attempt to acquire another TTY to be
b570d64b 282used for input.
69893cff 283
b570d64b 284=over
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285
286=item * 1 - on C<fork()>
287
288=item * 2 - debugger is started inside debugger
289
290=item * 4 - on startup
291
292=back
293
294=head4 C<$doret>
295
296The value -2 indicates that no return value should be printed.
297Any other positive value causes C<DB::sub> to print return values.
298
299=head4 C<$evalarg>
300
301The item to be eval'ed by C<DB::eval>. Used to prevent messing with the current
302contents of C<@_> when C<DB::eval> is called.
303
304=head4 C<$frame>
305
306Determines what messages (if any) will get printed when a subroutine (or eval)
b570d64b 307is entered or exited.
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308
309=over 4
310
311=item * 0 - No enter/exit messages
312
be9a9b1d 313=item * 1 - Print I<entering> messages on subroutine entry
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314
315=item * 2 - Adds exit messages on subroutine exit. If no other flag is on, acts like 1+2.
316
be9a9b1d 317=item * 4 - Extended messages: C<< <in|out> I<context>=I<fully-qualified sub name> from I<file>:I<line> >>. If no other flag is on, acts like 1+4.
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318
319=item * 8 - Adds parameter information to messages, and overloaded stringify and tied FETCH is enabled on the printed arguments. Ignored if C<4> is not on.
320
321=item * 16 - Adds C<I<context> return from I<subname>: I<value>> messages on subroutine/eval exit. Ignored if C<4> is is not on.
322
323=back
324
be9a9b1d 325To get everything, use C<$frame=30> (or C<o f=30> as a debugger command).
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326The debugger internally juggles the value of C<$frame> during execution to
327protect external modules that the debugger uses from getting traced.
328
329=head4 C<$level>
330
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331Tracks current debugger nesting level. Used to figure out how many
332C<E<lt>E<gt>> pairs to surround the line number with when the debugger
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333outputs a prompt. Also used to help determine if the program has finished
334during command parsing.
335
336=head4 C<$onetimeDump>
337
338Controls what (if anything) C<DB::eval()> will print after evaluating an
339expression.
340
341=over 4
342
343=item * C<undef> - don't print anything
344
345=item * C<dump> - use C<dumpvar.pl> to display the value returned
346
347=item * C<methods> - print the methods callable on the first item returned
348
349=back
350
351=head4 C<$onetimeDumpDepth>
352
be9a9b1d 353Controls how far down C<dumpvar.pl> will go before printing C<...> while
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354dumping a structure. Numeric. If C<undef>, print all levels.
355
356=head4 C<$signal>
357
358Used to track whether or not an C<INT> signal has been detected. C<DB::DB()>,
359which is called before every statement, checks this and puts the user into
360command mode if it finds C<$signal> set to a true value.
361
362=head4 C<$single>
363
364Controls behavior during single-stepping. Stacked in C<@stack> on entry to
365each subroutine; popped again at the end of each subroutine.
366
b570d64b 367=over 4
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368
369=item * 0 - run continuously.
370
be9a9b1d 371=item * 1 - single-step, go into subs. The C<s> command.
69893cff 372
be9a9b1d 373=item * 2 - single-step, don't go into subs. The C<n> command.
69893cff 374
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375=item * 4 - print current sub depth (turned on to force this when C<too much
376recursion> occurs.
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377
378=back
379
380=head4 C<$trace>
381
b570d64b 382Controls the output of trace information.
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383
384=over 4
385
386=item * 1 - The C<t> command was entered to turn on tracing (every line executed is printed)
387
388=item * 2 - watch expressions are active
389
390=item * 4 - user defined a C<watchfunction()> in C<afterinit()>
391
392=back
393
394=head4 C<$slave_editor>
395
3961 if C<LINEINFO> was directed to a pipe; 0 otherwise.
397
398=head4 C<@cmdfhs>
399
400Stack of filehandles that C<DB::readline()> will read commands from.
401Manipulated by the debugger's C<source> command and C<DB::readline()> itself.
402
403=head4 C<@dbline>
404
b570d64b 405Local alias to the magical line array, C<@{$main::{'_<'.$filename}}> ,
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406supplied by the Perl interpreter to the debugger. Contains the source.
407
408=head4 C<@old_watch>
409
410Previous values of watch expressions. First set when the expression is
411entered; reset whenever the watch expression changes.
412
413=head4 C<@saved>
414
415Saves important globals (C<$@>, C<$!>, C<$^E>, C<$,>, C<$/>, C<$\>, C<$^W>)
416so that the debugger can substitute safe values while it's running, and
417restore them when it returns control.
418
419=head4 C<@stack>
420
421Saves the current value of C<$single> on entry to a subroutine.
422Manipulated by the C<c> command to turn off tracing in all subs above the
423current one.
424
425=head4 C<@to_watch>
426
427The 'watch' expressions: to be evaluated before each line is executed.
428
429=head4 C<@typeahead>
430
431The typeahead buffer, used by C<DB::readline>.
432
433=head4 C<%alias>
434
435Command aliases. Stored as character strings to be substituted for a command
436entered.
437
438=head4 C<%break_on_load>
439
440Keys are file names, values are 1 (break when this file is loaded) or undef
441(don't break when it is loaded).
442
443=head4 C<%dbline>
444
be9a9b1d 445Keys are line numbers, values are C<condition\0action>. If used in numeric
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446context, values are 0 if not breakable, 1 if breakable, no matter what is
447in the actual hash entry.
448
449=head4 C<%had_breakpoints>
450
451Keys are file names; values are bitfields:
452
b570d64b 453=over 4
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454
455=item * 1 - file has a breakpoint in it.
456
457=item * 2 - file has an action in it.
458
459=back
460
461A zero or undefined value means this file has neither.
462
463=head4 C<%option>
464
465Stores the debugger options. These are character string values.
466
467=head4 C<%postponed>
468
469Saves breakpoints for code that hasn't been compiled yet.
470Keys are subroutine names, values are:
471
472=over 4
473
be9a9b1d 474=item * C<compile> - break when this sub is compiled
69893cff 475
be9a9b1d 476=item * C<< break +0 if <condition> >> - break (conditionally) at the start of this routine. The condition will be '1' if no condition was specified.
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477
478=back
479
480=head4 C<%postponed_file>
481
482This hash keeps track of breakpoints that need to be set for files that have
483not yet been compiled. Keys are filenames; values are references to hashes.
484Each of these hashes is keyed by line number, and its values are breakpoint
be9a9b1d 485definitions (C<condition\0action>).
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486
487=head1 DEBUGGER INITIALIZATION
488
489The debugger's initialization actually jumps all over the place inside this
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490package. This is because there are several BEGIN blocks (which of course
491execute immediately) spread through the code. Why is that?
69893cff 492
b570d64b 493The debugger needs to be able to change some things and set some things up
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494before the debugger code is compiled; most notably, the C<$deep> variable that
495C<DB::sub> uses to tell when a program has recursed deeply. In addition, the
496debugger has to turn off warnings while the debugger code is compiled, but then
497restore them to their original setting before the program being debugged begins
498executing.
499
500The first C<BEGIN> block simply turns off warnings by saving the current
501setting of C<$^W> and then setting it to zero. The second one initializes
502the debugger variables that are needed before the debugger begins executing.
b570d64b 503The third one puts C<$^X> back to its former value.
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504
505We'll detail the second C<BEGIN> block later; just remember that if you need
506to initialize something before the debugger starts really executing, that's
507where it has to go.
508
509=cut
510
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511package DB;
512
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513use strict;
514
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)) {
bc6438f2 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
98274836
JM
1227my $dev_tty = '/dev/tty';
1228 $dev_tty = 'TT:' if ($^O eq 'VMS');
6b24a4b7 1229use vars qw($rcfile);
98274836 1230if ( -e $dev_tty ) { # this is the wrong metric!
e22ea7cc
RF
1231 $rcfile = ".perldb";
1232}
69893cff
RGS
1233else {
1234 $rcfile = "perldb.ini";
d338d6fe
PP
1235}
1236
69893cff
RGS
1237=pod
1238
1239The debugger does a safety test of the file to be read. It must be owned
1240either by the current user or root, and must only be writable by the owner.
1241
1242=cut
1243
1244# This wraps a safety test around "do" to read and evaluate the init file.
1245#
055fd3a9
GS
1246# This isn't really safe, because there's a race
1247# between checking and opening. The solution is to
1248# open and fstat the handle, but then you have to read and
1249# eval the contents. But then the silly thing gets
69893cff
RGS
1250# your lexical scope, which is unfortunate at best.
1251sub safe_do {
055fd3a9
GS
1252 my $file = shift;
1253
1254 # Just exactly what part of the word "CORE::" don't you understand?
69893cff
RGS
1255 local $SIG{__WARN__};
1256 local $SIG{__DIE__};
055fd3a9 1257
e22ea7cc 1258 unless ( is_safe_file($file) ) {
69893cff 1259 CORE::warn <<EO_GRIPE;
055fd3a9 1260perldb: Must not source insecure rcfile $file.
b570d64b 1261 You or the superuser must be the owner, and it must not
69893cff 1262 be writable by anyone but its owner.
055fd3a9 1263EO_GRIPE
69893cff
RGS
1264 return;
1265 } ## end unless (is_safe_file($file...
055fd3a9
GS
1266
1267 do $file;
1268 CORE::warn("perldb: couldn't parse $file: $@") if $@;
69893cff 1269} ## end sub safe_do
055fd3a9 1270
69893cff
RGS
1271# This is the safety test itself.
1272#
055fd3a9
GS
1273# Verifies that owner is either real user or superuser and that no
1274# one but owner may write to it. This function is of limited use
1275# when called on a path instead of upon a handle, because there are
1276# no guarantees that filename (by dirent) whose file (by ino) is
e22ea7cc 1277# eventually accessed is the same as the one tested.
055fd3a9
GS
1278# Assumes that the file's existence is not in doubt.
1279sub is_safe_file {
1280 my $path = shift;
69893cff 1281 stat($path) || return; # mysteriously vaporized
e22ea7cc 1282 my ( $dev, $ino, $mode, $nlink, $uid, $gid ) = stat(_);
055fd3a9
GS
1283
1284 return 0 if $uid != 0 && $uid != $<;
1285 return 0 if $mode & 022;
1286 return 1;
69893cff 1287} ## end sub is_safe_file
055fd3a9 1288
69893cff 1289# If the rcfile (whichever one we decided was the right one to read)
e22ea7cc
RF
1290# exists, we safely do it.
1291if ( -f $rcfile ) {
055fd3a9 1292 safe_do("./$rcfile");
69893cff 1293}
e22ea7cc 1294
69893cff 1295# If there isn't one here, try the user's home directory.
e22ea7cc 1296elsif ( defined $ENV{HOME} && -f "$ENV{HOME}/$rcfile" ) {
055fd3a9
GS
1297 safe_do("$ENV{HOME}/$rcfile");
1298}
e22ea7cc 1299
69893cff 1300# Else try the login directory.
e22ea7cc 1301elsif ( defined $ENV{LOGDIR} && -f "$ENV{LOGDIR}/$rcfile" ) {
055fd3a9 1302 safe_do("$ENV{LOGDIR}/$rcfile");
d338d6fe
PP
1303}
1304
69893cff 1305# If the PERLDB_OPTS variable has options in it, parse those out next.
e22ea7cc
RF
1306if ( defined $ENV{PERLDB_OPTS} ) {
1307 parse_options( $ENV{PERLDB_OPTS} );
d338d6fe
PP
1308}
1309
69893cff
RGS
1310=pod
1311
1312The last thing we do during initialization is determine which subroutine is
1313to be used to obtain a new terminal when a new debugger is started. Right now,
b0b54b5e 1314the debugger only handles TCP sockets, X11, OS/2, amd Mac OS X
11653f7f 1315(darwin).
69893cff
RGS
1316
1317=cut
1318
1319# Set up the get_fork_TTY subroutine to be aliased to the proper routine.
1320# Works if you're running an xterm or xterm-like window, or you're on
6fae1ad7
RF
1321# OS/2, or on Mac OS X. This may need some expansion.
1322
1323if (not defined &get_fork_TTY) # only if no routine exists
69893cff 1324{
b570d64b 1325 if ( defined $remoteport ) {
11653f7f
JJ
1326 # Expect an inetd-like server
1327 *get_fork_TTY = \&socket_get_fork_TTY; # to listen to us
1328 }
1329 elsif (defined $ENV{TERM} # If we know what kind
6fae1ad7
RF
1330 # of terminal this is,
1331 and $ENV{TERM} eq 'xterm' # and it's an xterm,
1332 and defined $ENV{DISPLAY} # and what display it's on,
1333 )
1334 {
1335 *get_fork_TTY = \&xterm_get_fork_TTY; # use the xterm version
1336 }
1337 elsif ( $^O eq 'os2' ) { # If this is OS/2,
1338 *get_fork_TTY = \&os2_get_fork_TTY; # use the OS/2 version
1339 }
1340 elsif ( $^O eq 'darwin' # If this is Mac OS X
1341 and defined $ENV{TERM_PROGRAM} # and we're running inside
1342 and $ENV{TERM_PROGRAM}
1343 eq 'Apple_Terminal' # Terminal.app
1344 )
1345 {
1346 *get_fork_TTY = \&macosx_get_fork_TTY; # use the Mac OS X version
1347 }
69893cff 1348} ## end if (not defined &get_fork_TTY...
e22ea7cc 1349
dbb46cec
DQ
1350# untaint $^O, which may have been tainted by the last statement.
1351# see bug [perl #24674]
e22ea7cc
RF
1352$^O =~ m/^(.*)\z/;
1353$^O = $1;
f1583d8f 1354
d12a4851 1355# Here begin the unreadable code. It needs fixing.
055fd3a9 1356
69893cff
RGS
1357=head2 RESTART PROCESSING
1358
1359This section handles the restart command. When the C<R> command is invoked, it
1360tries to capture all of the state it can into environment variables, and
1361then sets C<PERLDB_RESTART>. When we start executing again, we check to see
1362if C<PERLDB_RESTART> is there; if so, we reload all the information that
1363the R command stuffed into the environment variables.
1364
b570d64b 1365 PERLDB_RESTART - flag only, contains no restart data itself.
69893cff
RGS
1366 PERLDB_HIST - command history, if it's available
1367 PERLDB_ON_LOAD - breakpoints set by the rc file
1368 PERLDB_POSTPONE - subs that have been loaded/not executed, and have actions
1369 PERLDB_VISITED - files that had breakpoints
1370 PERLDB_FILE_... - breakpoints for a file
1371 PERLDB_OPT - active options
1372 PERLDB_INC - the original @INC
1373 PERLDB_PRETYPE - preprompt debugger actions
1374 PERLDB_PRE - preprompt Perl code
1375 PERLDB_POST - post-prompt Perl code
1376 PERLDB_TYPEAHEAD - typeahead captured by readline()
1377
1378We chug through all these variables and plug the values saved in them
1379back into the appropriate spots in the debugger.
1380
1381=cut
1382
6b24a4b7
SF
1383use vars qw(@hist @truehist %postponed_file @typeahead);
1384
e22ea7cc
RF
1385if ( exists $ENV{PERLDB_RESTART} ) {
1386
69893cff 1387 # We're restarting, so we don't need the flag that says to restart anymore.
e22ea7cc
RF
1388 delete $ENV{PERLDB_RESTART};
1389
1390 # $restart = 1;
1391 @hist = get_list('PERLDB_HIST');
1392 %break_on_load = get_list("PERLDB_ON_LOAD");
1393 %postponed = get_list("PERLDB_POSTPONE");
69893cff 1394
2cbb2ee1
RGS
1395 share(@hist);
1396 share(@truehist);
1397 share(%break_on_load);
1398 share(%postponed);
1399
69893cff 1400 # restore breakpoints/actions
e22ea7cc 1401 my @had_breakpoints = get_list("PERLDB_VISITED");
bdba49ad
SF
1402 for my $file_idx ( 0 .. $#had_breakpoints ) {
1403 my $filename = $had_breakpoints[$file_idx];
1404 my %pf = get_list("PERLDB_FILE_$file_idx");
1405 $postponed_file{ $filename } = \%pf if %pf;
1406 my @lines = sort {$a <=> $b} keys(%pf);
1407 my @enabled_statuses = get_list("PERLDB_FILE_ENABLED_$file_idx");
1408 for my $line_idx (0 .. $#lines) {
1409 _set_breakpoint_enabled_status(
1410 $filename,
1411 $lines[$line_idx],
1412 ($enabled_statuses[$line_idx] ? 1 : ''),
1413 );
1414 }
e22ea7cc 1415 }
69893cff
RGS
1416
1417 # restore options
e22ea7cc
RF
1418 my %opt = get_list("PERLDB_OPT");
1419 my ( $opt, $val );
1420 while ( ( $opt, $val ) = each %opt ) {
1421 $val =~ s/[\\\']/\\$1/g;
1422 parse_options("$opt'$val'");
1423 }
69893cff
RGS
1424
1425 # restore original @INC
e22ea7cc
RF
1426 @INC = get_list("PERLDB_INC");
1427 @ini_INC = @INC;
1428
1429 # return pre/postprompt actions and typeahead buffer
1430 $pretype = [ get_list("PERLDB_PRETYPE") ];
1431 $pre = [ get_list("PERLDB_PRE") ];
1432 $post = [ get_list("PERLDB_POST") ];
1433 @typeahead = get_list( "PERLDB_TYPEAHEAD", @typeahead );
69893cff
RGS
1434} ## end if (exists $ENV{PERLDB_RESTART...
1435
1436=head2 SETTING UP THE TERMINAL
1437
1438Now, we'll decide how the debugger is going to interact with the user.
1439If there's no TTY, we set the debugger to run non-stop; there's not going
1440to be anyone there to enter commands.
1441
1442=cut
54d04a52 1443
6b24a4b7
SF
1444use vars qw($notty $runnonstop $console $tty $LINEINFO);
1445use vars qw($lineinfo $doccmd);
1446
d338d6fe 1447if ($notty) {
69893cff 1448 $runnonstop = 1;
2cbb2ee1 1449 share($runnonstop);
69893cff 1450}
d12a4851 1451
69893cff
RGS
1452=pod
1453
1454If there is a TTY, we have to determine who it belongs to before we can
1455proceed. If this is a slave editor or graphical debugger (denoted by
1456the first command-line switch being '-emacs'), we shift this off and
1457set C<$rl> to 0 (XXX ostensibly to do straight reads).
1458
1459=cut
1460
1461else {
e22ea7cc 1462
69893cff
RGS
1463 # Is Perl being run from a slave editor or graphical debugger?
1464 # If so, don't use readline, and set $slave_editor = 1.
e22ea7cc
RF
1465 $slave_editor =
1466 ( ( defined $main::ARGV[0] ) and ( $main::ARGV[0] eq '-emacs' ) );
1467 $rl = 0, shift(@main::ARGV) if $slave_editor;
1468
1469 #require Term::ReadLine;
d12a4851 1470
69893cff
RGS
1471=pod
1472
1473We then determine what the console should be on various systems:
1474
1475=over 4
1476
1477=item * Cygwin - We use C<stdin> instead of a separate device.
1478
1479=cut
1480
e22ea7cc
RF
1481 if ( $^O eq 'cygwin' ) {
1482
69893cff
RGS
1483 # /dev/tty is binary. use stdin for textmode
1484 undef $console;
1485 }
1486
1487=item * Unix - use C</dev/tty>.
1488
1489=cut
1490
e22ea7cc 1491 elsif ( -e "/dev/tty" ) {
69893cff
RGS
1492 $console = "/dev/tty";
1493 }
1494
1495=item * Windows or MSDOS - use C<con>.
1496
1497=cut
1498
e22ea7cc 1499 elsif ( $^O eq 'dos' or -e "con" or $^O eq 'MSWin32' ) {
69893cff
RGS
1500 $console = "con";
1501 }
1502
69893cff
RGS
1503=item * VMS - use C<sys$command>.
1504
1505=cut
1506
1507 else {
e22ea7cc 1508
69893cff
RGS
1509 # everything else is ...
1510 $console = "sys\$command";
d12a4851 1511 }
69893cff
RGS
1512
1513=pod
1514
1515=back
1516
1517Several other systems don't use a specific console. We C<undef $console>
1518for those (Windows using a slave editor/graphical debugger, NetWare, OS/2
1519with a slave editor, Epoc).
1520
1521=cut
d12a4851 1522
e22ea7cc
RF
1523 if ( ( $^O eq 'MSWin32' ) and ( $slave_editor or defined $ENV{EMACS} ) ) {
1524
69893cff 1525 # /dev/tty is binary. use stdin for textmode
e22ea7cc
RF
1526 $console = undef;
1527 }
1528
1529 if ( $^O eq 'NetWare' ) {
d12a4851 1530
69893cff
RGS
1531 # /dev/tty is binary. use stdin for textmode
1532 $console = undef;
1533 }
d12a4851 1534
69893cff
RGS
1535 # In OS/2, we need to use STDIN to get textmode too, even though
1536 # it pretty much looks like Unix otherwise.
e22ea7cc
RF
1537 if ( defined $ENV{OS2_SHELL} and ( $slave_editor or $ENV{WINDOWID} ) )
1538 { # In OS/2
1539 $console = undef;
1540 }
1541
1542 # EPOC also falls into the 'got to use STDIN' camp.
1543 if ( $^O eq 'epoc' ) {
1544 $console = undef;
1545 }
d12a4851 1546
69893cff
RGS
1547=pod
1548
1549If there is a TTY hanging around from a parent, we use that as the console.
1550
1551=cut
1552
e22ea7cc 1553 $console = $tty if defined $tty;
d12a4851 1554
b570d64b 1555=head2 SOCKET HANDLING
69893cff
RGS
1556
1557The debugger is capable of opening a socket and carrying out a debugging
1558session over the socket.
1559
1560If C<RemotePort> was defined in the options, the debugger assumes that it
1561should try to start a debugging session on that port. It builds the socket
1562and then tries to connect the input and output filehandles to it.
1563
1564=cut
1565
1566 # Handle socket stuff.
e22ea7cc
RF
1567
1568 if ( defined $remoteport ) {
1569
69893cff
RGS
1570 # If RemotePort was defined in the options, connect input and output
1571 # to the socket.
11653f7f 1572 $IN = $OUT = connect_remoteport();
69893cff
RGS
1573 } ## end if (defined $remoteport)
1574
1575=pod
1576
1577If no C<RemotePort> was defined, and we want to create a TTY on startup,
1578this is probably a situation where multiple debuggers are running (for example,
1579a backticked command that starts up another debugger). We create a new IN and
1580OUT filehandle, and do the necessary mojo to create a new TTY if we know how
1581and if we can.
1582
1583=cut
1584
1585 # Non-socket.
1586 else {
e22ea7cc 1587
69893cff
RGS
1588 # Two debuggers running (probably a system or a backtick that invokes
1589 # the debugger itself under the running one). create a new IN and OUT
e22ea7cc 1590 # filehandle, and do the necessary mojo to create a new tty if we
69893cff 1591 # know how, and we can.
e22ea7cc
RF
1592 create_IN_OUT(4) if $CreateTTY & 4;
1593 if ($console) {
1594
69893cff 1595 # If we have a console, check to see if there are separate ins and
cd1191f1 1596 # outs to open. (They are assumed identical if not.)
69893cff 1597
e22ea7cc
RF
1598 my ( $i, $o ) = split /,/, $console;
1599 $o = $i unless defined $o;
69893cff 1600
69893cff 1601 # read/write on in, or just read, or read on STDIN.
e22ea7cc
RF
1602 open( IN, "+<$i" )
1603 || open( IN, "<$i" )
1604 || open( IN, "<&STDIN" );
1605
69893cff
RGS
1606 # read/write/create/clobber out, or write/create/clobber out,
1607 # or merge with STDERR, or merge with STDOUT.
e22ea7cc
RF
1608 open( OUT, "+>$o" )
1609 || open( OUT, ">$o" )
1610 || open( OUT, ">&STDERR" )
1611 || open( OUT, ">&STDOUT" ); # so we don't dongle stdout
1612
1613 } ## end if ($console)
1614 elsif ( not defined $console ) {
1615
1616 # No console. Open STDIN.
1617 open( IN, "<&STDIN" );
1618
1619 # merge with STDERR, or with STDOUT.
1620 open( OUT, ">&STDERR" )
1621 || open( OUT, ">&STDOUT" ); # so we don't dongle stdout
1622 $console = 'STDIN/OUT';
69893cff
RGS
1623 } ## end elsif (not defined $console)
1624
1625 # Keep copies of the filehandles so that when the pager runs, it
1626 # can close standard input without clobbering ours.
e22ea7cc
RF
1627 $IN = \*IN, $OUT = \*OUT if $console or not defined $console;
1628 } ## end elsif (from if(defined $remoteport))
1629
1630 # Unbuffer DB::OUT. We need to see responses right away.
70c9432b 1631 $OUT->autoflush(1);
e22ea7cc
RF
1632
1633 # Line info goes to debugger output unless pointed elsewhere.
1634 # Pointing elsewhere makes it possible for slave editors to
1635 # keep track of file and position. We have both a filehandle
1636 # and a I/O description to keep track of.
1637 $LINEINFO = $OUT unless defined $LINEINFO;
1638 $lineinfo = $console unless defined $lineinfo;
2cbb2ee1 1639 # share($LINEINFO); # <- unable to share globs
b570d64b 1640 share($lineinfo); #
e22ea7cc 1641
69893cff
RGS
1642=pod
1643
1644To finish initialization, we show the debugger greeting,
1645and then call the C<afterinit()> subroutine if there is one.
1646
1647=cut
d12a4851 1648
e22ea7cc
RF
1649 # Show the debugger greeting.
1650 $header =~ s/.Header: ([^,]+),v(\s+\S+\s+\S+).*$/$1$2/;
1651 unless ($runnonstop) {
1652 local $\ = '';
1653 local $, = '';
1654 if ( $term_pid eq '-1' ) {
1655 print $OUT "\nDaughter DB session started...\n";
1656 }
1657 else {
1658 print $OUT "\nLoading DB routines from $header\n";
1659 print $OUT (
1660 "Editor support ",
1661 $slave_editor ? "enabled" : "available", ".\n"
1662 );
1663 print $OUT
1f874cb6 1664"\nEnter h or 'h h' for help, or '$doccmd perldebug' for more help.\n\n";
69893cff
RGS
1665 } ## end else [ if ($term_pid eq '-1')
1666 } ## end unless ($runnonstop)
1667} ## end else [ if ($notty)
1668
1669# XXX This looks like a bug to me.
1670# Why copy to @ARGS and then futz with @args?
d338d6fe 1671@ARGS = @ARGV;
6b24a4b7 1672# for (@args) {
69893cff
RGS
1673 # Make sure backslashes before single quotes are stripped out, and
1674 # keep args unless they are numeric (XXX why?)
e22ea7cc
RF
1675 # s/\'/\\\'/g; # removed while not justified understandably
1676 # s/(.*)/'$1'/ unless /^-?[\d.]+$/; # ditto
6b24a4b7 1677# }
d338d6fe 1678
e22ea7cc 1679# If there was an afterinit() sub defined, call it. It will get
69893cff 1680# executed in our scope, so it can fiddle with debugger globals.
e22ea7cc 1681if ( defined &afterinit ) { # May be defined in $rcfile
69893cff 1682 &afterinit();
d338d6fe 1683}
e22ea7cc 1684
69893cff 1685# Inform us about "Stack dump during die enabled ..." in dieLevel().
6b24a4b7
SF
1686use vars qw($I_m_init);
1687
43aed9ee
IZ
1688$I_m_init = 1;
1689
d338d6fe
PP
1690############################################################ Subroutines
1691
69893cff
RGS
1692=head1 SUBROUTINES
1693
1694=head2 DB
1695
1696This gigantic subroutine is the heart of the debugger. Called before every
1697statement, its job is to determine if a breakpoint has been reached, and
1698stop if so; read commands from the user, parse them, and execute
b468dcb6 1699them, and then send execution off to the next statement.
69893cff
RGS
1700
1701Note that the order in which the commands are processed is very important;
1702some commands earlier in the loop will actually alter the C<$cmd> variable
be9a9b1d 1703to create other commands to be executed later. This is all highly I<optimized>
69893cff
RGS
1704but can be confusing. Check the comments for each C<$cmd ... && do {}> to
1705see what's happening in any given command.
1706
1707=cut
1708
6b24a4b7
SF
1709use vars qw(
1710 $action
1711 %alias
1712 $cmd
1713 $doret
1714 $fall_off_end
1715 $file
1716 $filename_ini
1717 $finished
1718 %had_breakpoints
1719 $incr
1720 $laststep
1721 $level
1722 $max
1723 @old_watch
1724 $package
1725 $rc
1726 $sh
1727 @stack
1728 $stack_depth
1729 @to_watch
1730 $try
2c247e84 1731 $end
6b24a4b7
SF
1732);
1733
d338d6fe 1734sub DB {
69893cff 1735
2cbb2ee1
RGS
1736 # lock the debugger and get the thread id for the prompt
1737 lock($DBGR);
1738 my $tid;
6b24a4b7
SF
1739 my $position;
1740 my ($prefix, $after, $infix);
1741 my $pat;
6b24a4b7 1742
2cbb2ee1 1743 if ($ENV{PERL5DB_THREADED}) {
878090d5 1744 $tid = eval { "[".threads->tid."]" };
2cbb2ee1
RGS
1745 }
1746
69893cff 1747 # Check for whether we should be running continuously or not.
36477c24 1748 # _After_ the perl program is compiled, $single is set to 1:
e22ea7cc
RF
1749 if ( $single and not $second_time++ ) {
1750
69893cff 1751 # Options say run non-stop. Run until we get an interrupt.
e22ea7cc
RF
1752 if ($runnonstop) { # Disable until signal
1753 # If there's any call stack in place, turn off single
1754 # stepping into subs throughout the stack.
2c247e84 1755 for my $i (0 .. $stack_depth) {
72d7d80d 1756 $stack[ $i ] &= ~1;
e22ea7cc
RF
1757 }
1758
69893cff 1759 # And we are now no longer in single-step mode.
e22ea7cc 1760 $single = 0;
69893cff
RGS
1761
1762 # If we simply returned at this point, we wouldn't get
1763 # the trace info. Fall on through.
e22ea7cc 1764 # return;
69893cff
RGS
1765 } ## end if ($runnonstop)
1766
e22ea7cc
RF
1767 elsif ($ImmediateStop) {
1768
1769 # We are supposed to stop here; XXX probably a break.
1770 $ImmediateStop = 0; # We've processed it; turn it off
1771 $signal = 1; # Simulate an interrupt to force
1772 # us into the command loop
69893cff
RGS
1773 }
1774 } ## end if ($single and not $second_time...
1775
1776 # If we're in single-step mode, or an interrupt (real or fake)
1777 # has occurred, turn off non-stop mode.
1778 $runnonstop = 0 if $single or $signal;
1779
1780 # Preserve current values of $@, $!, $^E, $,, $/, $\, $^W.
1781 # The code being debugged may have altered them.
d338d6fe 1782 &save;
69893cff
RGS
1783
1784 # Since DB::DB gets called after every line, we can use caller() to
1785 # figure out where we last were executing. Sneaky, eh? This works because
e22ea7cc 1786 # caller is returning all the extra information when called from the
69893cff 1787 # debugger.
e22ea7cc 1788 local ( $package, $filename, $line ) = caller;
6b24a4b7 1789 $filename_ini = $filename;
69893cff
RGS
1790
1791 # set up the context for DB::eval, so it can properly execute
1792 # code on behalf of the user. We add the package in so that the
1793 # code is eval'ed in the proper package (not in the debugger!).
6b24a4b7 1794 local $usercontext = _calc_usercontext($package);
69893cff
RGS
1795
1796 # Create an alias to the active file magical array to simplify
1797 # the code here.
e22ea7cc 1798 local (*dbline) = $main::{ '_<' . $filename };
aa057b67 1799
69893cff 1800 # Last line in the program.
55783941 1801 $max = $#dbline;
69893cff
RGS
1802
1803 # if we have something here, see if we should break.
e22ea7cc 1804 {
72d7d80d
SF
1805 # $stop is lexical and local to this block - $action on the other hand
1806 # is global.
1807 my $stop;
e22ea7cc 1808
72d7d80d
SF
1809 if ( $dbline{$line}
1810 && _is_breakpoint_enabled($filename, $line)
1811 && (( $stop, $action ) = split( /\0/, $dbline{$line} ) ) )
1812 {
e22ea7cc 1813
72d7d80d
SF
1814 # Stop if the stop criterion says to just stop.
1815 if ( $stop eq '1' ) {
1816 $signal |= 1;
5d5d9ea3 1817 }
72d7d80d
SF
1818
1819 # It's a conditional stop; eval it in the user's context and
1820 # see if we should stop. If so, remove the one-time sigil.
1821 elsif ($stop) {
1822 $evalarg = "\$DB::signal |= 1 if do {$stop}";
1823 &eval;
1824 # If the breakpoint is temporary, then delete its enabled status.
1825 if ($dbline{$line} =~ s/;9($|\0)/$1/) {
1826 _cancel_breakpoint_temp_enabled_status($filename, $line);
1827 }
1828 }
1829 } ## end if ($dbline{$line} && ...
1830 }
69893cff
RGS
1831
1832 # Preserve the current stop-or-not, and see if any of the W
1833 # (watch expressions) has changed.
36477c24 1834 my $was_signal = $signal;
69893cff
RGS
1835
1836 # If we have any watch expressions ...
e22ea7cc 1837 if ( $trace & 2 ) {
2c247e84 1838 for my $n (0 .. $#to_watch) {
e22ea7cc
RF
1839 $evalarg = $to_watch[$n];
1840 local $onetimeDump; # Tell DB::eval() to not output results
69893cff
RGS
1841
1842 # Fix context DB::eval() wants to return an array, but
1843 # we need a scalar here.
e22ea7cc
RF
1844 my ($val) = join( "', '", &eval );
1845 $val = ( ( defined $val ) ? "'$val'" : 'undef' );
69893cff
RGS
1846
1847 # Did it change?
e22ea7cc
RF
1848 if ( $val ne $old_watch[$n] ) {
1849
69893cff 1850 # Yep! Show the difference, and fake an interrupt.
e22ea7cc
RF
1851 $signal = 1;
1852 print $OUT <<EOP;
405ff068 1853Watchpoint $n:\t$to_watch[$n] changed:
69893cff
RGS
1854 old value:\t$old_watch[$n]
1855 new value:\t$val
6027b9a3 1856EOP
e22ea7cc 1857 $old_watch[$n] = $val;
69893cff 1858 } ## end if ($val ne $old_watch...
2c247e84 1859 } ## end for my $n (0 ..
69893cff
RGS
1860 } ## end if ($trace & 2)
1861
1862=head2 C<watchfunction()>
1863
1864C<watchfunction()> is a function that can be defined by the user; it is a
b570d64b 1865function which will be run on each entry to C<DB::DB>; it gets the
69893cff
RGS
1866current package, filename, and line as its parameters.
1867
b570d64b 1868The watchfunction can do anything it likes; it is executing in the
69893cff
RGS
1869debugger's context, so it has access to all of the debugger's internal
1870data structures and functions.
1871
1872C<watchfunction()> can control the debugger's actions. Any of the following
1873will cause the debugger to return control to the user's program after
1874C<watchfunction()> executes:
1875
b570d64b 1876=over 4
69893cff 1877
be9a9b1d
AT
1878=item *
1879
1880Returning a false value from the C<watchfunction()> itself.
1881
1882=item *
1883
1884Altering C<$single> to a false value.
1885
1886=item *
69893cff 1887
be9a9b1d 1888Altering C<$signal> to a false value.
69893cff 1889
be9a9b1d 1890=item *
69893cff 1891
be9a9b1d 1892Turning off the C<4> bit in C<$trace> (this also disables the
69893cff
RGS
1893check for C<watchfunction()>. This can be done with
1894
1895 $trace &= ~4;
1896
1897=back
1898
1899=cut
1900
e22ea7cc 1901 # If there's a user-defined DB::watchfunction, call it with the
69893cff
RGS
1902 # current package, filename, and line. The function executes in
1903 # the DB:: package.
e22ea7cc
RF
1904 if ( $trace & 4 ) { # User-installed watch
1905 return
1906 if watchfunction( $package, $filename, $line )
1907 and not $single
1908 and not $was_signal
1909 and not( $trace & ~4 );
69893cff
RGS
1910 } ## end if ($trace & 4)
1911
e22ea7cc 1912 # Pick up any alteration to $signal in the watchfunction, and
69893cff 1913 # turn off the signal now.
6027b9a3 1914 $was_signal = $signal;
69893cff
RGS
1915 $signal = 0;
1916
1917=head2 GETTING READY TO EXECUTE COMMANDS
1918
1919The debugger decides to take control if single-step mode is on, the
1920C<t> command was entered, or the user generated a signal. If the program
1921has fallen off the end, we set things up so that entering further commands
1922won't cause trouble, and we say that the program is over.
1923
1924=cut
1925
8dc67a69
SF
1926 # Make sure that we always print if asked for explicitly regardless
1927 # of $trace_to_depth .
1928 my $explicit_stop = ($single || $was_signal);
1929
69893cff
RGS
1930 # Check to see if we should grab control ($single true,
1931 # trace set appropriately, or we got a signal).
8dc67a69 1932 if ( $explicit_stop || ( $trace & 1 ) ) {
e22ea7cc 1933
69893cff 1934 # Yes, grab control.
e22ea7cc
RF
1935 if ($slave_editor) {
1936
69893cff 1937 # Tell the editor to update its position.
e22ea7cc
RF
1938 $position = "\032\032$filename:$line:0\n";
1939 print_lineinfo($position);
1940 }
69893cff
RGS
1941
1942=pod
1943
b570d64b 1944Special check: if we're in package C<DB::fake>, we've gone through the
69893cff
RGS
1945C<END> block at least once. We set up everything so that we can continue
1946to enter commands and have a valid context to be in.
1947
1948=cut
1949
e22ea7cc 1950 elsif ( $package eq 'DB::fake' ) {
69893cff 1951
69893cff 1952 # Fallen off the end already.
e22ea7cc
RF
1953 $term || &setterm;
1954 print_help(<<EOP);
405ff068 1955Debugged program terminated. Use B<q> to quit or B<R> to restart,
6b27b0a0 1956 use B<o> I<inhibit_exit> to avoid stopping after program termination,
b570d64b 1957 B<h q>, B<h R> or B<h o> to get additional info.
405ff068 1958EOP
e22ea7cc 1959
69893cff 1960 # Set the DB::eval context appropriately.
e22ea7cc 1961 $package = 'main';
6b24a4b7 1962 $usercontext = _calc_usercontext($package);
69893cff 1963 } ## end elsif ($package eq 'DB::fake')
e219e2fb 1964
69893cff 1965=pod
e219e2fb 1966
69893cff
RGS
1967If the program hasn't finished executing, we scan forward to the
1968next executable line, print that out, build the prompt from the file and line
b570d64b 1969number information, and print that.
e219e2fb 1970
69893cff
RGS
1971=cut
1972
e22ea7cc
RF
1973 else {
1974
8dc67a69 1975
69893cff
RGS
1976 # Still somewhere in the midst of execution. Set up the
1977 # debugger prompt.
1978 $sub =~ s/\'/::/; # Swap Perl 4 package separators (') to
e22ea7cc 1979 # Perl 5 ones (sorry, we don't print Klingon
69893cff
RGS
1980 #module names)
1981
6b24a4b7 1982 $prefix = $sub =~ /::/ ? "" : ($package . '::');
e22ea7cc
RF
1983 $prefix .= "$sub($filename:";
1984 $after = ( $dbline[$line] =~ /\n$/ ? '' : "\n" );
69893cff
RGS
1985
1986 # Break up the prompt if it's really long.
e22ea7cc
RF
1987 if ( length($prefix) > 30 ) {
1988 $position = "$prefix$line):\n$line:\t$dbline[$line]$after";
1989 $prefix = "";
1990 $infix = ":\t";
1991 }
1992 else {
1993 $infix = "):\t";
1994 $position = "$prefix$line$infix$dbline[$line]$after";
1995 }
69893cff
RGS
1996
1997 # Print current line info, indenting if necessary.
e22ea7cc
RF
1998 if ($frame) {
1999 print_lineinfo( ' ' x $stack_depth,
2000 "$line:\t$dbline[$line]$after" );
2001 }
2002 else {
8dc67a69 2003 depth_print_lineinfo($explicit_stop, $position);
e22ea7cc 2004 }
69893cff
RGS
2005
2006 # Scan forward, stopping at either the end or the next
2007 # unbreakable line.
72d7d80d 2008 for ( my $i = $line + 1 ; $i <= $max && $dbline[$i] == 0 ; ++$i )
e22ea7cc 2009 { #{ vi
69893cff
RGS
2010
2011 # Drop out on null statements, block closers, and comments.
2012 last if $dbline[$i] =~ /^\s*[\;\}\#\n]/;
2013
2014 # Drop out if the user interrupted us.
2015 last if $signal;
2016
2017 # Append a newline if the line doesn't have one. Can happen
2018 # in eval'ed text, for instance.
e22ea7cc 2019 $after = ( $dbline[$i] =~ /\n$/ ? '' : "\n" );
69893cff
RGS
2020
2021 # Next executable line.
6b24a4b7 2022 my $incr_pos = "$prefix$i$infix$dbline[$i]$after";
69893cff
RGS
2023 $position .= $incr_pos;
2024 if ($frame) {
e22ea7cc 2025
69893cff 2026 # Print it indented if tracing is on.
e22ea7cc
RF
2027 print_lineinfo( ' ' x $stack_depth,
2028 "$i:\t$dbline[$i]$after" );
69893cff
RGS
2029 }
2030 else {
8dc67a69 2031 depth_print_lineinfo($explicit_stop, $incr_pos);
69893cff 2032 }
72d7d80d 2033 } ## end for ($i = $line + 1 ; $i...
69893cff
RGS
2034 } ## end else [ if ($slave_editor)
2035 } ## end if ($single || ($trace...
2036
2037=pod
2038
2039If there's an action to be executed for the line we stopped at, execute it.
b570d64b 2040If there are any preprompt actions, execute those as well.
e219e2fb
RF
2041
2042=cut
2043
69893cff
RGS
2044 # If there's an action, do it now.
2045 $evalarg = $action, &eval if $action;
e219e2fb 2046
69893cff
RGS
2047 # Are we nested another level (e.g., did we evaluate a function
2048 # that had a breakpoint in it at the debugger prompt)?
e22ea7cc
RF
2049 if ( $single || $was_signal ) {
2050
69893cff 2051 # Yes, go down a level.
e22ea7cc 2052 local $level = $level + 1;
69893cff
RGS
2053
2054 # Do any pre-prompt actions.
e22ea7cc
RF
2055 foreach $evalarg (@$pre) {
2056 &eval;
2057 }
69893cff
RGS
2058
2059 # Complain about too much recursion if we passed the limit.
e22ea7cc 2060 print $OUT $stack_depth . " levels deep in subroutine calls!\n"
69893cff
RGS
2061 if $single & 4;
2062
2063 # The line we're currently on. Set $incr to -1 to stay here
2064 # until we get a command that tells us to advance.
e22ea7cc
RF
2065 $start = $line;
2066 $incr = -1; # for backward motion.
69893cff
RGS
2067
2068 # Tack preprompt debugger actions ahead of any actual input.
e22ea7cc 2069 @typeahead = ( @$pretype, @typeahead );
69893cff
RGS
2070
2071=head2 WHERE ARE WE?
2072
2073XXX Relocate this section?
2074
2075The debugger normally shows the line corresponding to the current line of
2076execution. Sometimes, though, we want to see the next line, or to move elsewhere
2077in the file. This is done via the C<$incr>, C<$start>, and C<$max> variables.
2078
be9a9b1d
AT
2079C<$incr> controls by how many lines the I<current> line should move forward
2080after a command is executed. If set to -1, this indicates that the I<current>
69893cff
RGS
2081line shouldn't change.
2082
be9a9b1d 2083C<$start> is the I<current> line. It is used for things like knowing where to
69893cff
RGS
2084move forwards or backwards from when doing an C<L> or C<-> command.
2085
2086C<$max> tells the debugger where the last line of the current file is. It's
2087used to terminate loops most often.
2088
2089=head2 THE COMMAND LOOP
2090
2091Most of C<DB::DB> is actually a command parsing and dispatch loop. It comes
2092in two parts:
2093
2094=over 4
2095
be9a9b1d
AT
2096=item *
2097
2098The outer part of the loop, starting at the C<CMD> label. This loop
69893cff
RGS
2099reads a command and then executes it.
2100
be9a9b1d
AT
2101=item *
2102
2103The inner part of the loop, starting at the C<PIPE> label. This part
69893cff
RGS
2104is wholly contained inside the C<CMD> block and only executes a command.
2105Used to handle commands running inside a pager.
2106
2107=back
2108
2109So why have two labels to restart the loop? Because sometimes, it's easier to
2110have a command I<generate> another command and then re-execute the loop to do
2111the new command. This is faster, but perhaps a bit more convoluted.
2112
2113=cut
2114
2115 # The big command dispatch loop. It keeps running until the
2116 # user yields up control again.
2117 #
2118 # If we have a terminal for input, and we get something back
2119 # from readline(), keep on processing.
6b24a4b7
SF
2120 my $piped;
2121 my $selected;
2122
e22ea7cc
RF
2123 CMD:
2124 while (
2125
69893cff 2126 # We have a terminal, or can get one ...
e22ea7cc
RF
2127 ( $term || &setterm ),
2128
69893cff 2129 # ... and it belogs to this PID or we get one for this PID ...
e22ea7cc
RF
2130 ( $term_pid == $$ or resetterm(1) ),
2131
69893cff 2132 # ... and we got a line of command input ...
e22ea7cc
RF
2133 defined(
2134 $cmd = &readline(
2cbb2ee1 2135 "$pidprompt $tid DB"
e22ea7cc
RF
2136 . ( '<' x $level )
2137 . ( $#hist + 1 )
2138 . ( '>' x $level ) . " "
69893cff
RGS
2139 )
2140 )
2141 )
2142 {
e22ea7cc 2143
2cbb2ee1 2144 share($cmd);
69893cff
RGS
2145 # ... try to execute the input as debugger commands.
2146
2147 # Don't stop running.
2148 $single = 0;
2149
2150 # No signal is active.
2151 $signal = 0;
2152
2153 # Handle continued commands (ending with \):
3d7a2a93 2154 if ($cmd =~ s/\\\z/\n/) {
e22ea7cc
RF
2155 $cmd .= &readline(" cont: ");
2156 redo CMD;
3d7a2a93 2157 }
69893cff
RGS
2158
2159=head4 The null command
2160
be9a9b1d 2161A newline entered by itself means I<re-execute the last command>. We grab the
69893cff
RGS
2162command out of C<$laststep> (where it was recorded previously), and copy it
2163back into C<$cmd> to be executed below. If there wasn't any previous command,
2164we'll do nothing below (no command will match). If there was, we also save it
2165in the command history and fall through to allow the command parsing to pick
2166it up.
2167
2168=cut
2169
2170 # Empty input means repeat the last command.
e22ea7cc
RF
2171 $cmd =~ /^$/ && ( $cmd = $laststep );
2172 chomp($cmd); # get rid of the annoying extra newline
2173 push( @hist, $cmd ) if length($cmd) > 1;
2174 push( @truehist, $cmd );
2cbb2ee1
RGS
2175 share(@hist);
2176 share(@truehist);
e22ea7cc
RF
2177
2178 # This is a restart point for commands that didn't arrive
2179 # via direct user input. It allows us to 'redo PIPE' to
2180 # re-execute command processing without reading a new command.
69893cff 2181 PIPE: {
e22ea7cc
RF
2182 $cmd =~ s/^\s+//s; # trim annoying leading whitespace
2183 $cmd =~ s/\s+$//s; # trim annoying trailing whitespace
6b24a4b7 2184 my ($i) = split( /\s+/, $cmd );
69893cff
RGS
2185
2186=head3 COMMAND ALIASES
2187
2188The debugger can create aliases for commands (these are stored in the
2189C<%alias> hash). Before a command is executed, the command loop looks it up
2190in the alias hash and substitutes the contents of the alias for the command,
2191completely replacing it.
2192
2193=cut
2194
2195 # See if there's an alias for the command, and set it up if so.
e22ea7cc
RF
2196 if ( $alias{$i} ) {
2197
69893cff
RGS
2198 # Squelch signal handling; we want to keep control here
2199 # if something goes loco during the alias eval.
2200 local $SIG{__DIE__};
2201 local $SIG{__WARN__};
2202
2203 # This is a command, so we eval it in the DEBUGGER's
2204 # scope! Otherwise, we can't see the special debugger
2205 # variables, or get to the debugger's subs. (Well, we
2206 # _could_, but why make it even more complicated?)
2207 eval "\$cmd =~ $alias{$i}";
2208 if ($@) {
2209 local $\ = '';
1f874cb6 2210 print $OUT "Couldn't evaluate '$i' alias: $@";
69893cff
RGS
2211 next CMD;
2212 }
2213 } ## end if ($alias{$i})
2214
2215=head3 MAIN-LINE COMMANDS
2216
2217All of these commands work up to and after the program being debugged has
b570d64b 2218terminated.
69893cff
RGS
2219
2220=head4 C<q> - quit
2221
b570d64b 2222Quit the debugger. This entails setting the C<$fall_off_end> flag, so we don't
69893cff
RGS
2223try to execute further, cleaning any restart-related stuff out of the
2224environment, and executing with the last value of C<$?>.
2225
2226=cut
2227
3d7a2a93 2228 if ($cmd eq 'q') {
69893cff
RGS
2229 $fall_off_end = 1;
2230 clean_ENV();
2231 exit $?;
3d7a2a93 2232 }
69893cff 2233
611272bb 2234=head4 C<t> - trace [n]
69893cff
RGS
2235
2236Turn tracing on or off. Inverts the appropriate bit in C<$trace> (q.v.).
611272bb 2237If level is specified, set C<$trace_to_depth>.
69893cff
RGS
2238
2239=cut
2240
3d7a2a93 2241 if (my ($levels) = $cmd =~ /\At(?:\s+(\d+))?\z/) {
e22ea7cc
RF
2242 $trace ^= 1;
2243 local $\ = '';
611272bb 2244 $trace_to_depth = $levels ? $stack_depth + $levels : 1E9;
e22ea7cc 2245 print $OUT "Trace = "
611272bb
PS
2246 . ( ( $trace & 1 )
2247 ? ( $levels ? "on (to level $trace_to_depth)" : "on" )
2248 : "off" ) . "\n";
e22ea7cc 2249 next CMD;
3d7a2a93 2250 }
69893cff
RGS
2251
2252=head4 C<S> - list subroutines matching/not matching a pattern
2253
2254Walks through C<%sub>, checking to see whether or not to print the name.
2255
2256=cut
2257
826b9a2e
SF
2258 if (my ($print_all_subs, $should_reverse, $Spatt)
2259 = $cmd =~ /\AS(\s+(!)?(.+))?\z/) {
2260 # $Spatt is the pattern (if any) to use.
2261 # Reverse scan?
2262 my $Srev = defined $should_reverse;
2263 # No args - print all subs.
2264 my $Snocheck = !defined $print_all_subs;
69893cff
RGS
2265
2266 # Need to make these sane here.
e22ea7cc
RF
2267 local $\ = '';
2268 local $, = '';
69893cff
RGS
2269
2270 # Search through the debugger's magical hash of subs.
2271 # If $nocheck is true, just print the sub name.
2272 # Otherwise, check it against the pattern. We then use
2273 # the XOR trick to reverse the condition as required.
e22ea7cc
RF
2274 foreach $subname ( sort( keys %sub ) ) {
2275 if ( $Snocheck or $Srev ^ ( $subname =~ /$Spatt/ ) ) {
2276 print $OUT $subname, "\n";
2277 }
2278 }
2279 next CMD;
826b9a2e 2280 }
69893cff
RGS
2281
2282=head4 C<X> - list variables in current package
2283
b570d64b 2284Since the C<V> command actually processes this, just change this to the
69893cff
RGS
2285appropriate C<V> command and fall through.
2286
2287=cut
2288
e22ea7cc 2289 $cmd =~ s/^X\b/V $package/;
69893cff
RGS
2290
2291=head4 C<V> - list variables
2292
b570d64b 2293Uses C<dumpvar.pl> to dump out the current values for selected variables.
69893cff
RGS
2294
2295=cut
2296
2297 # Bare V commands get the currently-being-debugged package
2298 # added.
826b9a2e 2299 if ($cmd eq "V") {
e22ea7cc 2300 $cmd = "V $package";
826b9a2e 2301 }
69893cff
RGS
2302
2303 # V - show variables in package.
826b9a2e
SF
2304 if (my ($new_packname, $new_vars_str) =
2305 $cmd =~ /\AV\b\s*(\S+)\s*(.*)/) {
e22ea7cc 2306
69893cff
RGS
2307 # Save the currently selected filehandle and
2308 # force output to debugger's filehandle (dumpvar
2309 # just does "print" for output).
6b24a4b7 2310 my $savout = select($OUT);
69893cff
RGS
2311
2312 # Grab package name and variables to dump.
826b9a2e
SF
2313 $packname = $new_packname;
2314 my @vars = split( ' ', $new_vars_str );
69893cff
RGS
2315
2316 # If main::dumpvar isn't here, get it.
e81465be 2317 do 'dumpvar.pl' || die $@ unless defined &main::dumpvar;
e22ea7cc
RF
2318 if ( defined &main::dumpvar ) {
2319
69893cff
RGS
2320 # We got it. Turn off subroutine entry/exit messages
2321 # for the moment, along with return values.
e22ea7cc
RF
2322 local $frame = 0;
2323 local $doret = -2;
69893cff
RGS
2324
2325 # must detect sigpipe failures - not catching
2326 # then will cause the debugger to die.
2327 eval {
2328 &main::dumpvar(
2329 $packname,
2330 defined $option{dumpDepth}
e22ea7cc
RF
2331 ? $option{dumpDepth}
2332 : -1, # assume -1 unless specified
69893cff 2333 @vars
e22ea7cc
RF
2334 );
2335 };
2336
2337 # The die doesn't need to include the $@, because
2338 # it will automatically get propagated for us.
2339 if ($@) {
2340 die unless $@ =~ /dumpvar print failed/;
2341 }
2342 } ## end if (defined &main::dumpvar)
2343 else {
2344
2345 # Couldn't load dumpvar.
2346 print $OUT "dumpvar.pl not available.\n";
2347 }
69893cff 2348
69893cff 2349 # Restore the output filehandle, and go round again.
e22ea7cc
RF
2350 select($savout);
2351 next CMD;
826b9a2e 2352 }
69893cff
RGS
2353
2354=head4 C<x> - evaluate and print an expression
2355
2356Hands the expression off to C<DB::eval>, setting it up to print the value
2357via C<dumpvar.pl> instead of just printing it directly.
2358
2359=cut
2360
826b9a2e 2361 if ($cmd =~ s#\Ax\b# #) { # Remainder gets done by DB::eval()
e22ea7cc 2362 $onetimeDump = 'dump'; # main::dumpvar shows the output
69893cff
RGS
2363
2364 # handle special "x 3 blah" syntax XXX propagate
2365 # doc back to special variables.
826b9a2e 2366 if ( $cmd =~ s#\A\s*(\d+)(?=\s)# #) {
e22ea7cc
RF
2367 $onetimedumpDepth = $1;
2368 }
826b9a2e 2369 }
69893cff
RGS
2370
2371=head4 C<m> - print methods
2372
2373Just uses C<DB::methods> to determine what methods are available.
2374
2375=cut
2376
826b9a2e 2377 if ($cmd =~ s#\Am\s+([\w:]+)\s*\z# #) {
e22ea7cc
RF
2378 methods($1);
2379 next CMD;
826b9a2e 2380 }
69893cff
RGS
2381
2382 # m expr - set up DB::eval to do the work
826b9a2e 2383 if ($cmd =~ s#\Am\b# #) { # Rest gets done by DB::eval()
e22ea7cc 2384 $onetimeDump = 'methods'; # method output gets used there
826b9a2e 2385 }
69893cff
RGS
2386
2387=head4 C<f> - switch files
2388
2389=cut
2390
826b9a2e 2391 if (($file) = $cmd =~ /\Af\b\s*(.*)/) {
e22ea7cc 2392 $file =~ s/\s+$//;
69893cff
RGS
2393
2394 # help for no arguments (old-style was return from sub).
e22ea7cc
RF
2395 if ( !$file ) {
2396 print $OUT
2397 "The old f command is now the r command.\n"; # hint
2398 print $OUT "The new f command switches filenames.\n";
2399 next CMD;
2400 } ## end if (!$file)
69893cff
RGS
2401
2402 # if not in magic file list, try a close match.
e22ea7cc
RF
2403 if ( !defined $main::{ '_<' . $file } ) {
2404 if ( ($try) = grep( m#^_<.*$file#, keys %main:: ) ) {
2405 {
2406 $try = substr( $try, 2 );
1f874cb6 2407 print $OUT "Choosing $try matching '$file':\n";
e22ea7cc
RF
2408 $file = $try;
2409 }
2410 } ## end if (($try) = grep(m#^_<.*$file#...
2411 } ## end if (!defined $main::{ ...
69893cff
RGS
2412
2413 # If not successfully switched now, we failed.
e22ea7cc 2414 if ( !defined $main::{ '_<' . $file } ) {
1f874cb6 2415 print $OUT "No file matching '$file' is loaded.\n";
e22ea7cc
RF
2416 next CMD;
2417 }
69893cff 2418
e22ea7cc
RF
2419 # We switched, so switch the debugger internals around.
2420 elsif ( $file ne $filename ) {
2421 *dbline = $main::{ '_<' . $file };
2422 $max = $#dbline;
2423 $filename = $file;
2424 $start = 1;
2425 $cmd = "l";
2426 } ## end elsif ($file ne $filename)
2427
2428 # We didn't switch; say we didn't.
2429 else {
2430 print $OUT "Already in $file.\n";
2431 next CMD;
2432 }
826b9a2e 2433 }
69893cff
RGS
2434
2435=head4 C<.> - return to last-executed line.
2436
2437We set C<$incr> to -1 to indicate that the debugger shouldn't move ahead,
2438and then we look up the line in the magical C<%dbline> hash.
2439
2440=cut
2441
2442 # . command.
826b9a2e 2443 if ($cmd eq '.') {
e22ea7cc 2444 $incr = -1; # stay at current line
69893cff
RGS
2445
2446 # Reset everything to the old location.
e22ea7cc
RF
2447 $start = $line;
2448 $filename = $filename_ini;
2449 *dbline = $main::{ '_<' . $filename };
2450 $max = $#dbline;
69893cff
RGS
2451
2452 # Now where are we?
e22ea7cc
RF
2453 print_lineinfo($position);
2454 next CMD;
826b9a2e 2455 }
69893cff
RGS
2456
2457=head4 C<-> - back one window
2458
2459We change C<$start> to be one window back; if we go back past the first line,
2460we set it to be the first line. We ser C<$incr> to put us back at the
2461currently-executing line, and then put a C<l $start +> (list one window from
2462C<$start>) in C<$cmd> to be executed later.
2463
2464=cut
2465
2466 # - - back a window.
826b9a2e 2467 if ($cmd eq '-') {
e22ea7cc 2468
69893cff 2469 # back up by a window; go to 1 if back too far.
e22ea7cc
RF
2470 $start -= $incr + $window + 1;
2471 $start = 1 if $start <= 0;
2472 $incr = $window - 1;
69893cff
RGS
2473
2474 # Generate and execute a "l +" command (handled below).
e22ea7cc 2475 $cmd = 'l ' . ($start) . '+';
826b9a2e 2476 }
69893cff
RGS
2477
2478=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>, {, {{>
2479
2480In Perl 5.8.0, a realignment of the commands was done to fix up a number of
2481problems, most notably that the default case of several commands destroying
2482the user's work in setting watchpoints, actions, etc. We wanted, however, to
2483retain the old commands for those who were used to using them or who preferred
2484them. At this point, we check for the new commands and call C<cmd_wrapper> to
2485deal with them instead of processing them in-line.
2486
2487=cut
2488
2489 # All of these commands were remapped in perl 5.8.0;
e22ea7cc 2490 # we send them off to the secondary dispatcher (see below).
826b9a2e
SF
2491 if (my ($cmd_letter, $my_arg) = $cmd =~ /\A([aAbBeEhilLMoOPvwW]\b|[<>\{]{1,2})\s*(.*)/so) {
2492 &cmd_wrapper( $cmd_letter, $my_arg, $line );
e22ea7cc 2493 next CMD;
826b9a2e 2494 }
69893cff
RGS
2495
2496=head4 C<y> - List lexicals in higher scope
2497
826b9a2e 2498Uses C<PadWalker> to find the lexicals supplied as arguments in a scope
69893cff
RGS
2499above the current one and then displays then using C<dumpvar.pl>.
2500
2501=cut
2502
826b9a2e
SF
2503 if (my ($match_level, $match_vars)
2504 = $cmd =~ /^y(?:\s+(\d*)\s*(.*))?$/) {
69893cff
RGS
2505
2506 # See if we've got the necessary support.
2507 eval { require PadWalker; PadWalker->VERSION(0.08) }
2508 or &warn(
2509 $@ =~ /locate/
2510 ? "PadWalker module not found - please install\n"
2511 : $@
2512 )
2513 and next CMD;
2514
2515 # Load up dumpvar if we don't have it. If we can, that is.
e81465be 2516 do 'dumpvar.pl' || die $@ unless defined &main::dumpvar;
69893cff
RGS
2517 defined &main::dumpvar
2518 or print $OUT "dumpvar.pl not available.\n"
2519 and next CMD;
2520
2521 # Got all the modules we need. Find them and print them.
826b9a2e 2522 my @vars = split( ' ', $match_vars || '' );
69893cff
RGS
2523
2524 # Find the pad.
826b9a2e 2525 my $h = eval { PadWalker::peek_my( ( $match_level || 0 ) + 1 ) };
69893cff
RGS
2526
2527 # Oops. Can't find it.
2528 $@ and $@ =~ s/ at .*//, &warn($@), next CMD;
2529
2530 # Show the desired vars with dumplex().
2531 my $savout = select($OUT);
2532
2533 # Have dumplex dump the lexicals.
e22ea7cc 2534 dumpvar::dumplex( $_, $h->{$_},
69893cff 2535 defined $option{dumpDepth} ? $option{dumpDepth} : -1,
e22ea7cc
RF
2536 @vars )
2537 for sort keys %$h;
69893cff
RGS
2538 select($savout);
2539 next CMD;
826b9a2e 2540 }
69893cff
RGS
2541
2542=head3 COMMANDS NOT WORKING AFTER PROGRAM ENDS
2543
2544All of the commands below this point don't work after the program being
2545debugged has ended. All of them check to see if the program has ended; this
2546allows the commands to be relocated without worrying about a 'line of
2547demarcation' above which commands can be entered anytime, and below which
2548they can't.
2549
2550=head4 C<n> - single step, but don't trace down into subs
2551
2552Done by setting C<$single> to 2, which forces subs to execute straight through
be9a9b1d 2553when entered (see C<DB::sub>). We also save the C<n> command in C<$laststep>,
826b9a2e 2554so a null command knows what to re-execute.
69893cff
RGS
2555
2556=cut
2557
e22ea7cc 2558 # n - next
826b9a2e 2559 if ($cmd eq 'n') {
69893cff 2560 end_report(), next CMD if $finished and $level <= 1;
e22ea7cc 2561
69893cff
RGS
2562 # Single step, but don't enter subs.
2563 $single = 2;
e22ea7cc 2564
69893cff 2565 # Save for empty command (repeat last).
e22ea7cc
RF
2566 $laststep = $cmd;
2567 last CMD;
826b9a2e 2568 }
69893cff
RGS
2569
2570=head4 C<s> - single-step, entering subs
2571
826b9a2e 2572Sets C<$single> to 1, which causes C<DB::sub> to continue tracing inside
69893cff
RGS
2573subs. Also saves C<s> as C<$lastcmd>.
2574
2575=cut
2576
2577 # s - single step.
826b9a2e 2578 if ($cmd eq 's') {
e22ea7cc 2579
69893cff
RGS
2580 # Get out and restart the command loop if program
2581 # has finished.
e22ea7cc
RF
2582 end_report(), next CMD if $finished and $level <= 1;
2583
69893cff 2584 # Single step should enter subs.
e22ea7cc
RF
2585 $single = 1;
2586
69893cff 2587 # Save for empty command (repeat last).
e22ea7cc
RF
2588 $laststep = $cmd;
2589 last CMD;
826b9a2e 2590 }
69893cff
RGS
2591
2592=head4 C<c> - run continuously, setting an optional breakpoint
2593
2594Most of the code for this command is taken up with locating the optional
2595breakpoint, which is either a subroutine name or a line number. We set
2596the appropriate one-time-break in C<@dbline> and then turn off single-stepping
2597in this and all call levels above this one.
2598
2599=cut
2600
2601 # c - start continuous execution.
ef18ae63 2602 if (($i) = $cmd =~ m#\Ac\b\s*([\w:]*)\s*\z#) {
e22ea7cc 2603
69893cff
RGS
2604 # Hey, show's over. The debugged program finished
2605 # executing already.
2606 end_report(), next CMD if $finished and $level <= 1;
2607
2608 # Capture the place to put a one-time break.
ef18ae63 2609 $subname = $i;
69893cff 2610
e22ea7cc
RF
2611 # Probably not needed, since we finish an interactive
2612 # sub-session anyway...
2613 # local $filename = $filename;
2614 # local *dbline = *dbline; # XXX Would this work?!
69893cff
RGS
2615 #
2616 # The above question wonders if localizing the alias
2617 # to the magic array works or not. Since it's commented
2618 # out, we'll just leave that to speculation for now.
2619
2620 # If the "subname" isn't all digits, we'll assume it
2621 # is a subroutine name, and try to find it.
e22ea7cc
RF
2622 if ( $subname =~ /\D/ ) { # subroutine name
2623 # Qualify it to the current package unless it's
2624 # already qualified.
69893cff
RGS
2625 $subname = $package . "::" . $subname
2626 unless $subname =~ /::/;
e22ea7cc 2627
69893cff
RGS
2628 # find_sub will return "file:line_number" corresponding
2629 # to where the subroutine is defined; we call find_sub,
e22ea7cc 2630 # break up the return value, and assign it in one
69893cff 2631 # operation.
e22ea7cc 2632 ( $file, $i ) = ( find_sub($subname) =~ /^(.*):(.*)$/ );
69893cff
RGS
2633
2634 # Force the line number to be numeric.
e22ea7cc 2635 $i += 0;
69893cff
RGS
2636
2637 # If we got a line number, we found the sub.
e22ea7cc
RF
2638 if ($i) {
2639
69893cff
RGS
2640 # Switch all the debugger's internals around so
2641 # we're actually working with that file.
e22ea7cc
RF
2642 $filename = $file;
2643 *dbline = $main::{ '_<' . $filename };
2644
69893cff 2645 # Mark that there's a breakpoint in this file.
e22ea7cc
RF
2646 $had_breakpoints{$filename} |= 1;
2647
69893cff
RGS
2648 # Scan forward to the first executable line
2649 # after the 'sub whatever' line.
e22ea7cc
RF
2650 $max = $#dbline;
2651 ++$i while $dbline[$i] == 0 && $i < $max;
2652 } ## end if ($i)
69893cff
RGS
2653
2654 # We didn't find a sub by that name.
e22ea7cc
RF
2655 else {
2656 print $OUT "Subroutine $subname not found.\n";
2657 next CMD;
2658 }
2659 } ## end if ($subname =~ /\D/)
69893cff
RGS
2660
2661 # At this point, either the subname was all digits (an
2662 # absolute line-break request) or we've scanned through
2663 # the code following the definition of the sub, looking
2664 # for an executable, which we may or may not have found.
2665 #
2666 # If $i (which we set $subname from) is non-zero, we
e22ea7cc
RF
2667 # got a request to break at some line somewhere. On
2668 # one hand, if there wasn't any real subroutine name
2669 # involved, this will be a request to break in the current
2670 # file at the specified line, so we have to check to make
69893cff
RGS
2671 # sure that the line specified really is breakable.
2672 #
2673 # On the other hand, if there was a subname supplied, the
3c4b39be 2674 # preceding block has moved us to the proper file and
69893cff
RGS
2675 # location within that file, and then scanned forward
2676 # looking for the next executable line. We have to make
2677 # sure that one was found.
2678 #
2679 # On the gripping hand, we can't do anything unless the
2680 # current value of $i points to a valid breakable line.
2681 # Check that.
e22ea7cc
RF
2682 if ($i) {
2683
69893cff 2684 # Breakable?
e22ea7cc
RF
2685 if ( $dbline[$i] == 0 ) {
2686 print $OUT "Line $i not breakable.\n";
2687 next CMD;
2688 }
2689
69893cff 2690 # Yes. Set up the one-time-break sigil.
e22ea7cc 2691 $dbline{$i} =~ s/($|\0)/;9$1/; # add one-time-only b.p.
5d5d9ea3 2692 _enable_breakpoint_temp_enabled_status($filename, $i);
e22ea7cc 2693 } ## end if ($i)
69893cff
RGS
2694
2695 # Turn off stack tracing from here up.
2c247e84
SF
2696 for my $i (0 .. $stack_depth) {
2697 $stack[ $i ] &= ~1;
e22ea7cc
RF
2698 }
2699 last CMD;
ef18ae63 2700 }
69893cff
RGS
2701
2702=head4 C<r> - return from a subroutine
2703
2704For C<r> to work properly, the debugger has to stop execution again
2705immediately after the return is executed. This is done by forcing
2706single-stepping to be on in the call level above the current one. If
2707we are printing return values when a C<r> is executed, set C<$doret>
2708appropriately, and force us out of the command loop.
2709
2710=cut
2711
2712 # r - return from the current subroutine.
ef18ae63 2713 if ($cmd eq 'r') {
e22ea7cc 2714
98dc9551 2715 # Can't do anything if the program's over.
e22ea7cc
RF
2716 end_report(), next CMD if $finished and $level <= 1;
2717
69893cff 2718 # Turn on stack trace.
e22ea7cc
RF
2719 $stack[$stack_depth] |= 1;
2720
69893cff 2721 # Print return value unless the stack is empty.
e22ea7cc
RF
2722 $doret = $option{PrintRet} ? $stack_depth - 1 : -2;
2723 last CMD;
ef18ae63 2724 }
69893cff 2725
69893cff
RGS
2726=head4 C<T> - stack trace
2727
2728Just calls C<DB::print_trace>.
2729
2730=cut
2731
ef18ae63 2732 if ($cmd eq 'T') {
e22ea7cc
RF
2733 print_trace( $OUT, 1 ); # skip DB
2734 next CMD;
ef18ae63 2735 }
69893cff
RGS
2736
2737=head4 C<w> - List window around current line.
2738
2739Just calls C<DB::cmd_w>.
2740
2741=cut
2742
ef18ae63
SF
2743 if (my ($arg) = $cmd =~ /\Aw\b\s*(.*)/s) {
2744 &cmd_w( 'w', $arg );
2745 next CMD;
2746 }
69893cff
RGS
2747
2748=head4 C<W> - watch-expression processing.
2749
b570d64b 2750Just calls C<DB::cmd_W>.
69893cff
RGS
2751
2752=cut
2753
ef18ae63
SF
2754 if (my ($arg) = $cmd =~ /\AW\b\s*(.*)/s) {
2755 &cmd_W( 'W', $arg );
2756 next CMD;
2757 }
69893cff
RGS
2758
2759=head4 C</> - search forward for a string in the source
2760
ef18ae63 2761We take the argument and treat it as a pattern. If it turns out to be a
69893cff 2762bad one, we return the error we got from trying to C<eval> it and exit.
ef18ae63 2763If not, we create some code to do the search and C<eval> it so it can't
69893cff
RGS
2764mess us up.
2765
2766=cut
2767
ef18ae63
SF
2768 # The pattern as a string.
2769 use vars qw($inpat);
69893cff 2770
ef18ae63 2771 if (($inpat) = $cmd =~ m#\A/(.*)\z#) {
69893cff
RGS
2772
2773 # Remove the final slash.
e22ea7cc 2774 $inpat =~ s:([^\\])/$:$1:;
69893cff
RGS
2775
2776 # If the pattern isn't null ...
e22ea7cc 2777 if ( $inpat ne "" ) {
69893cff
RGS
2778
2779 # Turn of warn and die procesing for a bit.
e22ea7cc
RF
2780 local $SIG{__DIE__};
2781 local $SIG{__WARN__};
69893cff
RGS
2782
2783 # Create the pattern.
e22ea7cc
RF
2784 eval '$inpat =~ m' . "\a$inpat\a";
2785 if ( $@ ne "" ) {
2786
69893cff 2787 # Oops. Bad pattern. No biscuit.
e22ea7cc 2788 # Print the eval error and go back for more
69893cff 2789 # commands.
e22ea7cc
RF
2790 print $OUT "$@";
2791 next CMD;
2792 }
2793 $pat = $inpat;
2794 } ## end if ($inpat ne "")
69893cff
RGS
2795
2796 # Set up to stop on wrap-around.
e22ea7cc 2797 $end = $start;
69893cff
RGS
2798
2799 # Don't move off the current line.
e22ea7cc 2800 $incr = -1;
69893cff
RGS
2801
2802 # Done in eval so nothing breaks if the pattern
2803 # does something weird.
e22ea7cc
RF
2804 eval '
2805 for (;;) {
69893cff 2806 # Move ahead one line.
e22ea7cc 2807 ++$start;
69893cff
RGS
2808
2809 # Wrap if we pass the last line.
e22ea7cc 2810 $start = 1 if ($start > $max);
69893cff
RGS
2811
2812 # Stop if we have gotten back to this line again,
e22ea7cc 2813 last if ($start == $end);
69893cff
RGS
2814
2815 # A hit! (Note, though, that we are doing
2816 # case-insensitive matching. Maybe a qr//
2817 # expression would be better, so the user could
2818 # do case-sensitive matching if desired.
e22ea7cc
RF
2819 if ($dbline[$start] =~ m' . "\a$pat\a" . 'i) {
2820 if ($slave_editor) {
69893cff 2821 # Handle proper escaping in the slave.
e22ea7cc 2822 print $OUT "\032\032$filename:$start:0\n";
b570d64b 2823 }
e22ea7cc 2824 else {
69893cff 2825 # Just print the line normally.
e22ea7cc
RF
2826 print $OUT "$start:\t",$dbline[$start],"\n";
2827 }
69893cff 2828 # And quit since we found something.
e22ea7cc
RF
2829 last;
2830 }
2831 } ';
2832
69893cff 2833 # If we wrapped, there never was a match.
e22ea7cc
RF
2834 print $OUT "/$pat/: not found\n" if ( $start == $end );
2835 next CMD;
ef18ae63 2836 }
69893cff
RGS
2837
2838=head4 C<?> - search backward for a string in the source
2839
2840Same as for C</>, except the loop runs backwards.
2841
2842=cut
2843
2844 # ? - backward pattern search.
ef18ae63 2845 if (my ($inpat) = $cmd =~ m#\A\?(.*)\z#) {
69893cff
RGS
2846
2847 # Get the pattern, remove trailing question mark.
e22ea7cc 2848 $inpat =~ s:([^\\])\?$:$1:;
69893cff
RGS
2849
2850 # If we've got one ...
e22ea7cc 2851 if ( $inpat ne "" ) {
69893cff
RGS
2852
2853 # Turn off die & warn handlers.
e22ea7cc
RF
2854 local $SIG{__DIE__};
2855 local $SIG{__WARN__};
2856 eval '$inpat =~ m' . "\a$inpat\a";
2857
2858 if ( $@ ne "" ) {
2859
69893cff 2860 # Ouch. Not good. Print the error.
e22ea7cc
RF
2861 print $OUT $@;
2862 next CMD;
2863 }
2864 $pat = $inpat;
69893cff 2865 } ## end if ($inpat ne "")
e22ea7cc 2866
69893cff 2867 # Where we are now is where to stop after wraparound.
e22ea7cc 2868 $end = $start;
69893cff
RGS
2869
2870 # Don't move away from this line.
e22ea7cc 2871 $incr = -1;
69893cff
RGS
2872
2873 # Search inside the eval to prevent pattern badness
2874 # from killing us.
e22ea7cc
RF
2875 eval '
2876 for (;;) {
69893cff 2877 # Back up a line.
e22ea7cc 2878 --$start;
69893cff
RGS
2879
2880 # Wrap if we pass the first line.
e22ea7cc
RF
2881
2882 $start = $max if ($start <= 0);
69893cff
RGS
2883
2884 # Quit if we get back where we started,
e22ea7cc 2885 last if ($start == $end);
69893cff
RGS
2886
2887 # Match?
e22ea7cc
RF
2888 if ($dbline[$start] =~ m' . "\a$pat\a" . 'i) {
2889 if ($slave_editor) {
69893cff 2890 # Yep, follow slave editor requirements.
e22ea7cc 2891 print $OUT "\032\032$filename:$start:0\n";
b570d64b 2892 }
e22ea7cc 2893 else {
69893cff 2894 # Yep, just print normally.
e22ea7cc
RF
2895 print $OUT "$start:\t",$dbline[$start],"\n";
2896 }
69893cff
RGS
2897
2898 # Found, so done.
e22ea7cc
RF
2899 last;
2900 }
2901 } ';
2902
2903 # Say we failed if the loop never found anything,
2904 print $OUT "?$pat?: not found\n" if ( $start == $end );
2905 next CMD;
ef18ae63 2906 }
69893cff
RGS
2907
2908=head4 C<$rc> - Recall command
2909
2910Manages the commands in C<@hist> (which is created if C<Term::ReadLine> reports
2911that the terminal supports history). It find the the command required, puts it
2912into C<$cmd>, and redoes the loop to execute it.
2913
2914=cut
2915
e22ea7cc 2916 # $rc - recall command.
ef18ae63 2917 if (my ($minus, $arg) = $cmd =~ m#\A$rc+\s*(-)?(\d+)?\z#) {
69893cff
RGS
2918
2919 # No arguments, take one thing off history.
e22ea7cc 2920 pop(@hist) if length($cmd) > 1;
69893cff 2921
e22ea7cc 2922 # Relative (- found)?
69893cff 2923 # Y - index back from most recent (by 1 if bare minus)
e22ea7cc 2924 # N - go to that particular command slot or the last
69893cff 2925 # thing if nothing following.
ef18ae63 2926 $i = $minus ? ( $#hist - ( $arg || 1 ) ) : ( $arg || $#hist );
69893cff
RGS
2927
2928 # Pick out the command desired.
e22ea7cc 2929 $cmd = $hist[$i];
69893cff
RGS
2930
2931 # Print the command to be executed and restart the loop
2932 # with that command in the buffer.
e22ea7cc
RF
2933 print $OUT $cmd, "\n";
2934 redo CMD;
ef18ae63 2935 }
69893cff
RGS
2936
2937=head4 C<$sh$sh> - C<system()> command
2938
2939Calls the C<DB::system()> to handle the command. This keeps the C<STDIN> and
2940C<STDOUT> from getting messed up.
2941
2942=cut
2943
2944 # $sh$sh - run a shell command (if it's all ASCII).
2945 # Can't run shell commands with Unicode in the debugger, hmm.
ef18ae63 2946 if (my ($arg) = $cmd =~ m#\A$sh$sh\s*(.*)#ms) {
e22ea7cc 2947
69893cff 2948 # System it.
ef18ae63 2949 &system($arg);
e22ea7cc 2950 next CMD;
ef18ae63 2951 }
69893cff
RGS
2952
2953=head4 C<$rc I<pattern> $rc> - Search command history
2954
2955Another command to manipulate C<@hist>: this one searches it with a pattern.
be9a9b1d 2956If a command is found, it is placed in C<$cmd> and executed via C<redo>.
69893cff
RGS
2957
2958=cut
2959
e22ea7cc 2960 # $rc pattern $rc - find a command in the history.
ef18ae63 2961 if (my ($arg) = $cmd =~ /\A$rc([^$rc].*)\z/) {
e22ea7cc 2962
69893cff 2963 # Create the pattern to use.
ef18ae63 2964 $pat = "^$arg";
69893cff
RGS
2965
2966 # Toss off last entry if length is >1 (and it always is).
e22ea7cc 2967 pop(@hist) if length($cmd) > 1;
69893cff
RGS
2968
2969 # Look backward through the history.
72d7d80d 2970 for ( $i = $#hist ; $i ; --$i ) {
69893cff 2971 # Stop if we find it.
e22ea7cc
RF
2972 last if $hist[$i] =~ /$pat/;
2973 }
2974
2975 if ( !$i ) {
69893cff 2976
69893cff 2977 # Never found it.
e22ea7cc
RF
2978 print $OUT "No such command!\n\n";
2979 next CMD;
2980 }
69893cff
RGS
2981
2982 # Found it. Put it in the buffer, print it, and process it.
e22ea7cc
RF
2983 $cmd = $hist[$i];
2984 print $OUT $cmd, "\n";
2985 redo CMD;
ef18ae63 2986 }
69893cff 2987
ef18ae63 2988=head4 C<$sh> - Invoke a shell
69893cff
RGS
2989
2990Uses C<DB::system> to invoke a shell.
2991
2992=cut
2993
2994 # $sh - start a shell.
ef18ae63 2995 if ($cmd =~ /\A$sh\z/) {
e22ea7cc 2996
69893cff
RGS
2997 # Run the user's shell. If none defined, run Bourne.
2998 # We resume execution when the shell terminates.
e22ea7cc
RF
2999 &system( $ENV{SHELL} || "/bin/sh" );
3000 next CMD;
ef18ae63 3001 }
69893cff
RGS
3002
3003=head4 C<$sh I<command>> - Force execution of a command in a shell
3004
3005Like the above, but the command is passed to the shell. Again, we use
3006C<DB::system> to avoid problems with C<STDIN> and C<STDOUT>.
3007
3008=cut
3009
3010 # $sh command - start a shell and run a command in it.
ef18ae63 3011 if (my ($arg) = $cmd =~ m#\A$sh\s*(.*)#ms) {
e22ea7cc
RF
3012
3013 # XXX: using csh or tcsh destroys sigint retvals!
3014 #&system($1); # use this instead
69893cff
RGS
3015
3016 # use the user's shell, or Bourne if none defined.
ef18ae63 3017 &system( $ENV{SHELL} || "/bin/sh", "-c", $arg );
e22ea7cc 3018 next CMD;
ef18ae63 3019 }
69893cff
RGS
3020
3021=head4 C<H> - display commands in history
3022
3023Prints the contents of C<@hist> (if any).
3024
3025=cut
3026
ef18ae63 3027 if ($cmd =~ /\AH\b\s*\*/) {
7fddc82f
RF
3028 @hist = @truehist = ();
3029 print $OUT "History cleansed\n";
3030 next CMD;
ef18ae63 3031 }
e22ea7cc 3032
ef18ae63
SF
3033 if (my ($num)
3034 = $cmd =~ /\AH\b\s*(?:-(\d+))?/) {
e22ea7cc
RF
3035
3036 # Anything other than negative numbers is ignored by
69893cff 3037 # the (incorrect) pattern, so this test does nothing.
ef18ae63 3038 $end = $num ? ( $#hist - $num ) : 0;
69893cff
RGS
3039
3040 # Set to the minimum if less than zero.
e22ea7cc 3041 $hist = 0 if $hist < 0;
69893cff 3042
e22ea7cc 3043 # Start at the end of the array.
69893cff
RGS
3044 # Stay in while we're still above the ending value.
3045 # Tick back by one each time around the loop.
72d7d80d 3046 for ( $i = $#hist ; $i > $end ; $i-- ) {
69893cff
RGS
3047
3048 # Print the command unless it has no arguments.
e22ea7cc
RF
3049 print $OUT "$i: ", $hist[$i], "\n"
3050 unless $hist[$i] =~ /^.?$/;
3051 }
3052 next CMD;
ef18ae63 3053 }
69893cff
RGS
3054
3055=head4 C<man, doc, perldoc> - look up documentation
3056
3057Just calls C<runman()> to print the appropriate document.
3058
3059=cut
3060
e22ea7cc 3061 # man, perldoc, doc - show manual pages.
ef18ae63
SF
3062 if (my ($man_page)
3063 = $cmd =~ /\A(?:man|(?:perl)?doc)\b(?:\s+([^(]*))?\z/) {
3064 runman($man_page);
e22ea7cc 3065 next CMD;
ef18ae63 3066 }
69893cff
RGS
3067
3068=head4 C<p> - print
3069
3070Builds a C<print EXPR> expression in the C<$cmd>; this will get executed at
3071the bottom of the loop.
3072
3073=cut
3074
ef18ae63 3075 my $print_cmd = 'print {$DB::OUT} ';
69893cff 3076 # p - print (no args): print $_.
ef18ae63
SF
3077 if ($cmd eq 'p') {
3078 $cmd = $print_cmd . '$_';
3079 }
69893cff
RGS
3080
3081 # p - print the given expression.
ef18ae63 3082 $cmd =~ s/\Ap\b/$print_cmd /;
69893cff
RGS
3083
3084=head4 C<=> - define command alias
3085
3086Manipulates C<%alias> to add or list command aliases.
3087
3088=cut
3089
e22ea7cc 3090 # = - set up a command alias.
ef18ae63 3091 if ($cmd =~ s/\A=\s*//) {
e22ea7cc
RF
3092 my @keys;
3093 if ( length $cmd == 0 ) {
3094
69893cff 3095 # No args, get current aliases.
e22ea7cc
RF
3096 @keys = sort keys %alias;
3097 }
3098 elsif ( my ( $k, $v ) = ( $cmd =~ /^(\S+)\s+(\S.*)/ ) ) {
3099
69893cff
RGS
3100 # Creating a new alias. $k is alias name, $v is
3101 # alias value.
3102
e22ea7cc
RF
3103 # can't use $_ or kill //g state
3104 for my $x ( $k, $v ) {
3105
3106 # Escape "alarm" characters.
3107 $x =~ s/\a/\\a/g;
3108 }
69893cff
RGS
3109
3110 # Substitute key for value, using alarm chars
e22ea7cc 3111 # as separators (which is why we escaped them in
69893cff 3112 # the command).
e22ea7cc 3113 $alias{$k} = "s\a$k\a$v\a";
69893cff
RGS
3114
3115 # Turn off standard warn and die behavior.
e22ea7cc
RF
3116 local $SIG{__DIE__};
3117 local $SIG{__WARN__};
69893cff
RGS
3118
3119 # Is it valid Perl?
e22ea7cc
RF
3120 unless ( eval "sub { s\a$k\a$v\a }; 1" ) {
3121
69893cff 3122 # Nope. Bad alias. Say so and get out.
e22ea7cc
RF
3123 print $OUT "Can't alias $k to $v: $@\n";
3124 delete $alias{$k};
3125 next CMD;
3126 }
3127
69893cff 3128 # We'll only list the new one.
e22ea7cc 3129 @keys = ($k);
69893cff
RGS
3130 } ## end elsif (my ($k, $v) = ($cmd...
3131
3132 # The argument is the alias to list.
e22ea7cc
RF
3133 else {
3134 @keys = ($cmd);
3135 }
69893cff
RGS
3136
3137 # List aliases.
e22ea7cc
RF
3138 for my $k (@keys) {
3139
98dc9551 3140 # Messy metaquoting: Trim the substitution code off.
69893cff
RGS
3141 # We use control-G as the delimiter because it's not
3142 # likely to appear in the alias.
e22ea7cc
RF
3143 if ( ( my $v = $alias{$k} ) =~ s\as\a$k\a(.*)\a$\a1\a ) {
3144
69893cff 3145 # Print the alias.
e22ea7cc
RF
3146 print $OUT "$k\t= $1\n";
3147 }
3148 elsif ( defined $alias{$k} ) {
3149
69893cff 3150 # Couldn't trim it off; just print the alias code.
e22ea7cc
RF
3151 print $OUT "$k\t$alias{$k}\n";
3152 }
3153 else {
3154
69893cff 3155 # No such, dude.
e22ea7cc
RF
3156 print "No alias for $k\n";
3157 }
69893cff 3158 } ## end for my $k (@keys)
e22ea7cc 3159 next CMD;
ef18ae63 3160 }
69893cff
RGS
3161
3162=head4 C<source> - read commands from a file.
3163
3164Opens a lexical filehandle and stacks it on C<@cmdfhs>; C<DB::readline> will
3165pick it up.
3166
3167=cut
3168
e22ea7cc 3169 # source - read commands from a file (or pipe!) and execute.
ef18ae63
SF
3170 if (my ($sourced_fn) = $cmd =~ /\Asource\s+(.*\S)/) {
3171 if ( open my $fh, $sourced_fn ) {
e22ea7cc 3172
69893cff 3173 # Opened OK; stick it in the list of file handles.
e22ea7cc
RF
3174 push @cmdfhs, $fh;
3175 }
3176 else {
3177
3178 # Couldn't open it.
ef18ae63 3179 &warn("Can't execute '$sourced_fn': $!\n");
e22ea7cc
RF
3180 }
3181 next CMD;
ef18ae63 3182 }
69893cff 3183
ef18ae63
SF
3184 if (my ($which_cmd, $position)
3185 = $cmd =~ /^(enable|disable)\s+(\S+)\s*$/) {
e09195af
SF
3186
3187 my ($fn, $line_num);
3188 if ($position =~ m{\A\d+\z})
3189 {
3190 $fn = $filename;
3191 $line_num = $position;
3192 }
ef18ae63
SF
3193 elsif (my ($new_fn, $new_line_num)
3194 = $position =~ m{\A(.*):(\d+)\z}) {
3195 ($fn, $line_num) = ($new_fn, $new_line_num);
e09195af
SF
3196 }
3197 else
3198 {
3199 &warn("Wrong spec for enable/disable argument.\n");
3200 }
3201
3202 if (defined($fn)) {
3203 if (_has_breakpoint_data_ref($fn, $line_num)) {
3204 _set_breakpoint_enabled_status($fn, $line_num,
ef18ae63 3205 ($which_cmd eq 'enable' ? 1 : '')
e09195af
SF
3206 );
3207 }
3208 else {
3209 &warn("No breakpoint set at ${fn}:${line_num}\n");
3210 }
3211 }
3212
3213 next CMD;
ef18ae63 3214 }
e09195af 3215
69893cff
RGS
3216=head4 C<save> - send current history to a file
3217
3218Takes the complete history, (not the shrunken version you see with C<H>),
3219and saves it to the given filename, so it can be replayed using C<source>.
3220
3221Note that all C<^(save|source)>'s are commented out with a view to minimise recursion.
3222
3223=cut
3224
3225 # save source - write commands to a file for later use
ef18ae63
SF
3226 if (my ($new_fn) = $cmd =~ /\Asave\s*(.*)\z/) {
3227 my $filename = $new_fn || '.perl5dbrc'; # default?
3228 if ( open my $fh, '>', $filename ) {
e22ea7cc
RF
3229
3230 # chomp to remove extraneous newlines from source'd files
3231 chomp( my @truelist =
3232 map { m/^\s*(save|source)/ ? "#$_" : $_ }
3233 @truehist );
3234 print $fh join( "\n", @truelist );
69893cff 3235 print "commands saved in $file\n";
e22ea7cc
RF
3236 }
3237 else {
ef18ae63 3238 &warn("Can't save debugger commands in '$new_fn': $!\n");
69893cff
RGS
3239 }
3240 next CMD;
ef18ae63 3241 }
69893cff 3242
7fddc82f
RF
3243=head4 C<R> - restart
3244
ef18ae63 3245Restart the debugger session.
7fddc82f
RF
3246
3247=head4 C<rerun> - rerun the current session
3248
3249Return to any given position in the B<true>-history list
3250
3251=cut
3252
3253 # R - restart execution.
3254 # rerun - controlled restart execution.
ff41e38d
SF
3255 if (my ($cmd_cmd, $cmd_params) =
3256 $cmd =~ /\A((?:R)|(?:rerun\s*(.*)))\z/) {
3257 my @args = ($cmd_cmd eq 'R' ? restart() : rerun($cmd_params));
7fddc82f 3258
ca28b541
AP
3259 # Close all non-system fds for a clean restart. A more
3260 # correct method would be to close all fds that were not
3261 # open when the process started, but this seems to be
3262 # hard. See "debugger 'R'estart and open database
3263 # connections" on p5p.
3264
47d3bbda 3265 my $max_fd = 1024; # default if POSIX can't be loaded
ca28b541 3266 if (eval { require POSIX }) {
5332cc68 3267 eval { $max_fd = POSIX::sysconf(POSIX::_SC_OPEN_MAX()) };
ca28b541
AP
3268 }
3269
3270 if (defined $max_fd) {
3271 foreach ($^F+1 .. $max_fd-1) {
3272 next unless open FD_TO_CLOSE, "<&=$_";
3273 close(FD_TO_CLOSE);
3274 }
3275 }
3276
7fddc82f
RF
3277 # And run Perl again. We use exec() to keep the
3278 # PID stable (and that way $ini_pids is still valid).
3279 exec(@args) || print $OUT "exec failed: $!\n";
3280
3281 last CMD;
ff41e38d 3282 }
7fddc82f 3283
69893cff
RGS
3284=head4 C<|, ||> - pipe output through the pager.
3285
be9a9b1d 3286For C<|>, we save C<OUT> (the debugger's output filehandle) and C<STDOUT>
69893cff
RGS
3287(the program's standard output). For C<||>, we only save C<OUT>. We open a
3288pipe to the pager (restoring the output filehandles if this fails). If this
b570d64b 3289is the C<|> command, we also set up a C<SIGPIPE> handler which will simply
69893cff
RGS
3290set C<$signal>, sending us back into the debugger.
3291
3292We then trim off the pipe symbols and C<redo> the command loop at the
3293C<PIPE> label, causing us to evaluate the command in C<$cmd> without
3294reading another.
3295
3296=cut
3297
3298 # || - run command in the pager, with output to DB::OUT.
ff41e38d 3299 if ($cmd =~ m#\A\|\|?\s*[^|]#) {
e22ea7cc
RF
3300 if ( $pager =~ /^\|/ ) {
3301
69893cff 3302 # Default pager is into a pipe. Redirect I/O.
e22ea7cc
RF
3303 open( SAVEOUT, ">&STDOUT" )
3304 || &warn("Can't save STDOUT");
3305 open( STDOUT, ">&OUT" )
3306 || &warn("Can't redirect STDOUT");
69893cff 3307 } ## end if ($pager =~ /^\|/)
e22ea7cc
RF
3308 else {
3309
69893cff 3310 # Not into a pipe. STDOUT is safe.
e22ea7cc
RF
3311 open( SAVEOUT, ">&OUT" ) || &warn("Can't save DB::OUT");
3312 }
69893cff
RGS
3313
3314 # Fix up environment to record we have less if so.
e22ea7cc
RF
3315 fix_less();
3316
3317 unless ( $piped = open( OUT, $pager ) ) {
69893cff 3318
69893cff 3319 # Couldn't open pipe to pager.
1f874cb6 3320 &warn("Can't pipe output to '$pager'");
e22ea7cc
RF
3321 if ( $pager =~ /^\|/ ) {
3322
69893cff 3323 # Redirect I/O back again.
e22ea7cc
RF
3324 open( OUT, ">&STDOUT" ) # XXX: lost message
3325 || &warn("Can't restore DB::OUT");
3326 open( STDOUT, ">&SAVEOUT" )
3327 || &warn("Can't restore STDOUT");
3328 close(SAVEOUT);
69893cff 3329 } ## end if ($pager =~ /^\|/)
e22ea7cc
RF
3330 else {
3331
69893cff 3332 # Redirect I/O. STDOUT already safe.
e22ea7cc
RF
3333 open( OUT, ">&STDOUT" ) # XXX: lost message
3334 || &warn("Can't restore DB::OUT");
3335 }
3336 next CMD;
69893cff
RGS
3337 } ## end unless ($piped = open(OUT,...
3338
3339 # Set up broken-pipe handler if necessary.
e22ea7cc
RF
3340 $SIG{PIPE} = \&DB::catch
3341 if $pager =~ /^\|/
3342 && ( "" eq $SIG{PIPE} || "DEFAULT" eq $SIG{PIPE} );
69893cff 3343
70c9432b
SF
3344 OUT->autoflush(1);
3345 # Save current filehandle, and put it back.
e22ea7cc 3346 $selected = select(OUT);
69893cff 3347 # Don't put it back if pager was a pipe.
e22ea7cc 3348 select($selected), $selected = "" unless $cmd =~ /^\|\|/;
69893cff
RGS
3349
3350 # Trim off the pipe symbols and run the command now.
ff41e38d 3351 $cmd =~ s#\A\|+\s*##;
e22ea7cc 3352 redo PIPE;
ff41e38d 3353 }
69893cff
RGS
3354
3355=head3 END OF COMMAND PARSING
3356
ff41e38d
SF
3357Anything left in C<$cmd> at this point is a Perl expression that we want to
3358evaluate. We'll always evaluate in the user's context, and fully qualify
69893cff
RGS
3359any variables we might want to address in the C<DB> package.
3360
3361=cut
3362
3363 # t - turn trace on.
ff41e38d
SF
3364 if ($cmd =~ s#\At\s+(\d+)?#\$DB::trace |= 1;\n#) {
3365 my $trace_arg = $1;
3366 $trace_to_depth = $trace_arg ? $stack_depth||0 + $1 : 1E9;
3367 }
69893cff
RGS
3368
3369 # s - single-step. Remember the last command was 's'.
ff41e38d
SF
3370 if ($cmd =~ s/\As\s/\$DB::single = 1;\n/) {
3371 $laststep = 's';
3372 }
69893cff
RGS
3373
3374 # n - single-step, but not into subs. Remember last command
e22ea7cc 3375 # was 'n'.
ff41e38d
SF
3376 if ($cmd =~ s#\An\s#\$DB::single = 2;\n#) {
3377 $laststep = 'n';
3378 }
69893cff 3379
e22ea7cc 3380 } # PIPE:
69893cff 3381
e22ea7cc 3382 # Make sure the flag that says "the debugger's running" is
69893cff 3383 # still on, to make sure we get control again.
e22ea7cc 3384 $evalarg = "\$^D = \$^D | \$DB::db_stop;\n$cmd";
69893cff
RGS
3385
3386 # Run *our* eval that executes in the caller's context.
e22ea7cc 3387 &eval;
69893cff
RGS
3388
3389 # Turn off the one-time-dump stuff now.
e22ea7cc
RF
3390 if ($onetimeDump) {
3391 $onetimeDump = undef;
69893cff 3392 $onetimedumpDepth = undef;
e22ea7cc
RF
3393 }
3394 elsif ( $term_pid == $$ ) {
c7e68384
IZ
3395 eval { # May run under miniperl, when not available...
3396 STDOUT->flush();
3397 STDERR->flush();
3398 };
e22ea7cc 3399
69893cff 3400 # XXX If this is the master pid, print a newline.
e22ea7cc
RF
3401 print $OUT "\n";
3402 }
3403 } ## end while (($term || &setterm...
69893cff
RGS
3404
3405=head3 POST-COMMAND PROCESSING
3406
3407After each command, we check to see if the command output was piped anywhere.
3408If so, we go through the necessary code to unhook the pipe and go back to
3409our standard filehandles for input and output.
3410
3411=cut
3412
e22ea7cc 3413 continue { # CMD:
69893cff
RGS
3414
3415 # At the end of every command:
e22ea7cc
RF
3416 if ($piped) {
3417
69893cff 3418 # Unhook the pipe mechanism now.
e22ea7cc
RF
3419 if ( $pager =~ /^\|/ ) {
3420
69893cff 3421 # No error from the child.
e22ea7cc 3422 $? = 0;
69893cff 3423
e22ea7cc
RF
3424 # we cannot warn here: the handle is missing --tchrist
3425 close(OUT) || print SAVEOUT "\nCan't close DB::OUT\n";
69893cff 3426
e22ea7cc 3427 # most of the $? crud was coping with broken cshisms
69893cff 3428 # $? is explicitly set to 0, so this never runs.
e22ea7cc 3429 if ($?) {
1f874cb6 3430 print SAVEOUT "Pager '$pager' failed: ";
e22ea7cc
RF
3431 if ( $? == -1 ) {
3432 print SAVEOUT "shell returned -1\n";
3433 }
3434 elsif ( $? >> 8 ) {
3435 print SAVEOUT ( $? & 127 )
3436 ? " (SIG#" . ( $? & 127 ) . ")"
3437 : "", ( $? & 128 ) ? " -- core dumped" : "", "\n";
3438 }
3439 else {
3440 print SAVEOUT "status ", ( $? >> 8 ), "\n";
3441 }
69893cff
RGS
3442 } ## end if ($?)
3443
e22ea7cc 3444 # Reopen filehandle for our output (if we can) and
69893cff 3445 # restore STDOUT (if we can).
e22ea7cc
RF
3446 open( OUT, ">&STDOUT" ) || &warn("Can't restore DB::OUT");
3447 open( STDOUT, ">&SAVEOUT" )
3448 || &warn("Can't restore STDOUT");
69893cff
RGS
3449
3450 # Turn off pipe exception handler if necessary.
e22ea7cc 3451 $SIG{PIPE} = "DEFAULT" if $SIG{PIPE} eq \&DB::catch;
69893cff 3452
e22ea7cc
RF
3453 # Will stop ignoring SIGPIPE if done like nohup(1)
3454 # does SIGINT but Perl doesn't give us a choice.
69893cff 3455 } ## end if ($pager =~ /^\|/)
e22ea7cc
RF
3456 else {
3457
69893cff 3458 # Non-piped "pager". Just restore STDOUT.
e22ea7cc
RF
3459 open( OUT, ">&SAVEOUT" ) || &warn("Can't restore DB::OUT");
3460 }
69893cff
RGS
3461
3462 # Close filehandle pager was using, restore the normal one
3463 # if necessary,
3464 close(SAVEOUT);
e22ea7cc 3465 select($selected), $selected = "" unless $selected eq "";
69893cff
RGS
3466
3467 # No pipes now.
e22ea7cc 3468 $piped = "";
69893cff 3469 } ## end if ($piped)
e22ea7cc 3470 } # CMD:
69893cff
RGS
3471
3472=head3 COMMAND LOOP TERMINATION
3473
3474When commands have finished executing, we come here. If the user closed the
3475input filehandle, we turn on C<$fall_off_end> to emulate a C<q> command. We
3476evaluate any post-prompt items. We restore C<$@>, C<$!>, C<$^E>, C<$,>, C<$/>,
3477C<$\>, and C<$^W>, and return a null list as expected by the Perl interpreter.
3478The interpreter will then execute the next line and then return control to us
3479again.
3480
3481=cut
3482
3483 # No more commands? Quit.
1f874cb6 3484 $fall_off_end = 1 unless defined $cmd; # Emulate 'q' on EOF
69893cff
RGS
3485
3486 # Evaluate post-prompt commands.
e22ea7cc
RF
3487 foreach $evalarg (@$post) {
3488 &eval;
3489 }
3490 } # if ($single || $signal)
69893cff
RGS
3491
3492 # Put the user's globals back where you found them.
e22ea7cc 3493 ( $@, $!, $^E, $,, $/, $\, $^W ) = @saved;
69893cff
RGS
3494 ();
3495} ## end sub DB
3496
3497# The following code may be executed now:
3498# BEGIN {warn 4}
3499
3500=head2 sub
3501
b570d64b 3502C<sub> is called whenever a subroutine call happens in the program being
69893cff
RGS
3503debugged. The variable C<$DB::sub> contains the name of the subroutine
3504being called.
3505
3506The core function of this subroutine is to actually call the sub in the proper
3507context, capturing its output. This of course causes C<DB::DB> to get called
3508again, repeating until the subroutine ends and returns control to C<DB::sub>
3509again. Once control returns, C<DB::sub> figures out whether or not to dump the
3510return value, and returns its captured copy of the return value as its own
3511return value. The value then feeds back into the program being debugged as if
3512C<DB::sub> hadn't been there at all.
3513
3514C<sub> does all the work of printing the subroutine entry and exit messages
3515enabled by setting C<$frame>. It notes what sub the autoloader got called for,
b570d64b 3516and also prints the return value if needed (for the C<r> command and if
69893cff
RGS
3517the 16 bit is set in C<$frame>).
3518
3519It also tracks the subroutine call depth by saving the current setting of
3520C<$single> in the C<@stack> package global; if this exceeds the value in
3521C<$deep>, C<sub> automatically turns on printing of the current depth by
be9a9b1d 3522setting the C<4> bit in C<$single>. In any case, it keeps the current setting
69893cff
RGS
3523of stop/don't stop on entry to subs set as it currently is set.
3524
3525=head3 C<caller()> support
3526
3527If C<caller()> is called from the package C<DB>, it provides some
3528additional data, in the following order:
3529
3530=over 4
3531
3532=item * C<$package>
3533
3534The package name the sub was in
3535
3536=item * C<$filename>
3537
3538The filename it was defined in
3539
3540=item * C<$line>
3541
3542The line number it was defined on
3543
3544=item * C<$subroutine>
3545
be9a9b1d 3546The subroutine name; C<(eval)> if an C<eval>().