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[perl5db] Refactoring.
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e22ea7cc 1
b570d64b 2=head1 NAME
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be9a9b1d 4perl5db.pl - the perl debugger
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5
6=head1 SYNOPSIS
7
8 perl -d your_Perl_script
9
10=head1 DESCRIPTION
11
12C<perl5db.pl> is the perl debugger. It is loaded automatically by Perl when
13you invoke a script with C<perl -d>. This documentation tries to outline the
14structure and services provided by C<perl5db.pl>, and to describe how you
15can use them.
16
17=head1 GENERAL NOTES
18
19The debugger can look pretty forbidding to many Perl programmers. There are
20a number of reasons for this, many stemming out of the debugger's history.
21
22When the debugger was first written, Perl didn't have a lot of its nicer
23features - no references, no lexical variables, no closures, no object-oriented
24programming. So a lot of the things one would normally have done using such
b570d64b 25features was done using global variables, globs and the C<local()> operator
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26in creative ways.
27
28Some of these have survived into the current debugger; a few of the more
29interesting and still-useful idioms are noted in this section, along with notes
30on the comments themselves.
31
32=head2 Why not use more lexicals?
33
34Experienced Perl programmers will note that the debugger code tends to use
35mostly package globals rather than lexically-scoped variables. This is done
36to allow a significant amount of control of the debugger from outside the
b570d64b 37debugger itself.
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38
39Unfortunately, though the variables are accessible, they're not well
40documented, so it's generally been a decision that hasn't made a lot of
41difference to most users. Where appropriate, comments have been added to
42make variables more accessible and usable, with the understanding that these
be9a9b1d 43I<are> debugger internals, and are therefore subject to change. Future
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44development should probably attempt to replace the globals with a well-defined
45API, but for now, the variables are what we've got.
46
47=head2 Automated variable stacking via C<local()>
48
b570d64b 49As you may recall from reading C<perlfunc>, the C<local()> operator makes a
69893cff 50temporary copy of a variable in the current scope. When the scope ends, the
b570d64b 51old copy is restored. This is often used in the debugger to handle the
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52automatic stacking of variables during recursive calls:
53
54 sub foo {
55 local $some_global++;
56
57 # Do some stuff, then ...
58 return;
59 }
60
61What happens is that on entry to the subroutine, C<$some_global> is localized,
b570d64b 62then altered. When the subroutine returns, Perl automatically undoes the
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63localization, restoring the previous value. Voila, automatic stack management.
64
b570d64b 65The debugger uses this trick a I<lot>. Of particular note is C<DB::eval>,
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66which lets the debugger get control inside of C<eval>'ed code. The debugger
67localizes a saved copy of C<$@> inside the subroutine, which allows it to
68keep C<$@> safe until it C<DB::eval> returns, at which point the previous
b570d64b 69value of C<$@> is restored. This makes it simple (well, I<simpler>) to keep
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70track of C<$@> inside C<eval>s which C<eval> other C<eval's>.
71
72In any case, watch for this pattern. It occurs fairly often.
73
74=head2 The C<^> trick
75
b570d64b 76This is used to cleverly reverse the sense of a logical test depending on
69893cff 77the value of an auxiliary variable. For instance, the debugger's C<S>
b570d64b 78(search for subroutines by pattern) allows you to negate the pattern
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79like this:
80
81 # Find all non-'foo' subs:
b570d64b 82 S !/foo/
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83
84Boolean algebra states that the truth table for XOR looks like this:
85
86=over 4
87
b570d64b 88=item * 0 ^ 0 = 0
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89
90(! not present and no match) --> false, don't print
91
b570d64b 92=item * 0 ^ 1 = 1
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93
94(! not present and matches) --> true, print
95
b570d64b 96=item * 1 ^ 0 = 1
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97
98(! present and no match) --> true, print
99
b570d64b 100=item * 1 ^ 1 = 0
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101
102(! present and matches) --> false, don't print
103
104=back
105
106As you can see, the first pair applies when C<!> isn't supplied, and
be9a9b1d 107the second pair applies when it is. The XOR simply allows us to
b570d64b 108compact a more complicated if-then-elseif-else into a more elegant
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109(but perhaps overly clever) single test. After all, it needed this
110explanation...
111
112=head2 FLAGS, FLAGS, FLAGS
113
114There is a certain C programming legacy in the debugger. Some variables,
be9a9b1d 115such as C<$single>, C<$trace>, and C<$frame>, have I<magical> values composed
69893cff 116of 1, 2, 4, etc. (powers of 2) OR'ed together. This allows several pieces
b570d64b 117of state to be stored independently in a single scalar.
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118
119A test like
120
121 if ($scalar & 4) ...
122
b570d64b 123is checking to see if the appropriate bit is on. Since each bit can be
69893cff 124"addressed" independently in this way, C<$scalar> is acting sort of like
b570d64b 125an array of bits. Obviously, since the contents of C<$scalar> are just a
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126bit-pattern, we can save and restore it easily (it will just look like
127a number).
128
129The problem, is of course, that this tends to leave magic numbers scattered
b570d64b 130all over your program whenever a bit is set, cleared, or checked. So why do
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131it?
132
133=over 4
134
be9a9b1d 135=item *
69893cff 136
be9a9b1d 137First, doing an arithmetical or bitwise operation on a scalar is
69893cff 138just about the fastest thing you can do in Perl: C<use constant> actually
be9a9b1d 139creates a subroutine call, and array and hash lookups are much slower. Is
b570d64b 140this over-optimization at the expense of readability? Possibly, but the
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141debugger accesses these variables a I<lot>. Any rewrite of the code will
142probably have to benchmark alternate implementations and see which is the
b570d64b 143best balance of readability and speed, and then document how it actually
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144works.
145
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146=item *
147
b570d64b 148Second, it's very easy to serialize a scalar number. This is done in
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149the restart code; the debugger state variables are saved in C<%ENV> and then
150restored when the debugger is restarted. Having them be just numbers makes
b570d64b 151this trivial.
69893cff 152
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153=item *
154
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155Third, some of these variables are being shared with the Perl core
156smack in the middle of the interpreter's execution loop. It's much faster for
157a C program (like the interpreter) to check a bit in a scalar than to access
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158several different variables (or a Perl array).
159
160=back
161
162=head2 What are those C<XXX> comments for?
163
164Any comment containing C<XXX> means that the comment is either somewhat
b570d64b 165speculative - it's not exactly clear what a given variable or chunk of
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166code is doing, or that it is incomplete - the basics may be clear, but the
167subtleties are not completely documented.
168
169Send in a patch if you can clear up, fill out, or clarify an C<XXX>.
170
b570d64b 171=head1 DATA STRUCTURES MAINTAINED BY CORE
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172
173There are a number of special data structures provided to the debugger by
174the Perl interpreter.
175
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176The array C<@{$main::{'_<'.$filename}}> (aliased locally to C<@dbline>
177via glob assignment) contains the text from C<$filename>, with each
178element corresponding to a single line of C<$filename>. Additionally,
179breakable lines will be dualvars with the numeric component being the
180memory address of a COP node. Non-breakable lines are dualvar to 0.
69893cff 181
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182The hash C<%{'_<'.$filename}> (aliased locally to C<%dbline> via glob
183assignment) contains breakpoints and actions. The keys are line numbers;
184you can set individual values, but not the whole hash. The Perl interpreter
69893cff 185uses this hash to determine where breakpoints have been set. Any true value is
be9a9b1d 186considered to be a breakpoint; C<perl5db.pl> uses C<$break_condition\0$action>.
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187Values are magical in numeric context: 1 if the line is breakable, 0 if not.
188
ef18ae63 189The scalar C<${"_<$filename"}> simply contains the string C<<< _<$filename> >>>.
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190This is also the case for evaluated strings that contain subroutines, or
191which are currently being executed. The $filename for C<eval>ed strings looks
d24ca0c5 192like C<(eval 34).
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193
194=head1 DEBUGGER STARTUP
195
196When C<perl5db.pl> starts, it reads an rcfile (C<perl5db.ini> for
197non-interactive sessions, C<.perldb> for interactive ones) that can set a number
198of options. In addition, this file may define a subroutine C<&afterinit>
b570d64b 199that will be executed (in the debugger's context) after the debugger has
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200initialized itself.
201
b570d64b 202Next, it checks the C<PERLDB_OPTS> environment variable and treats its
be9a9b1d 203contents as the argument of a C<o> command in the debugger.
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204
205=head2 STARTUP-ONLY OPTIONS
206
207The following options can only be specified at startup.
208To set them in your rcfile, add a call to
209C<&parse_options("optionName=new_value")>.
210
211=over 4
212
b570d64b 213=item * TTY
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214
215the TTY to use for debugging i/o.
216
b570d64b 217=item * noTTY
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218
219if set, goes in NonStop mode. On interrupt, if TTY is not set,
b0e77abc 220uses the value of noTTY or F<$HOME/.perldbtty$$> to find TTY using
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221Term::Rendezvous. Current variant is to have the name of TTY in this
222file.
223
b570d64b 224=item * ReadLine
69893cff 225
5561b870 226if false, a dummy ReadLine is used, so you can debug
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227ReadLine applications.
228
b570d64b 229=item * NonStop
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230
231if true, no i/o is performed until interrupt.
232
b570d64b 233=item * LineInfo
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234
235file or pipe to print line number info to. If it is a
236pipe, a short "emacs like" message is used.
237
b570d64b 238=item * RemotePort
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239
240host:port to connect to on remote host for remote debugging.
241
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242=item * HistFile
243
244file to store session history to. There is no default and so no
245history file is written unless this variable is explicitly set.
246
247=item * HistSize
248
249number of commands to store to the file specified in C<HistFile>.
250Default is 100.
251
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252=back
253
254=head3 SAMPLE RCFILE
255
256 &parse_options("NonStop=1 LineInfo=db.out");
257 sub afterinit { $trace = 1; }
258
259The script will run without human intervention, putting trace
260information into C<db.out>. (If you interrupt it, you had better
be9a9b1d 261reset C<LineInfo> to something I<interactive>!)
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262
263=head1 INTERNALS DESCRIPTION
264
265=head2 DEBUGGER INTERFACE VARIABLES
266
267Perl supplies the values for C<%sub>. It effectively inserts
be9a9b1d 268a C<&DB::DB();> in front of each place that can have a
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269breakpoint. At each subroutine call, it calls C<&DB::sub> with
270C<$DB::sub> set to the called subroutine. It also inserts a C<BEGIN
271{require 'perl5db.pl'}> before the first line.
272
273After each C<require>d file is compiled, but before it is executed, a
274call to C<&DB::postponed($main::{'_<'.$filename})> is done. C<$filename>
275is the expanded name of the C<require>d file (as found via C<%INC>).
276
277=head3 IMPORTANT INTERNAL VARIABLES
278
279=head4 C<$CreateTTY>
280
281Used to control when the debugger will attempt to acquire another TTY to be
b570d64b 282used for input.
69893cff 283
b570d64b 284=over
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285
286=item * 1 - on C<fork()>
287
288=item * 2 - debugger is started inside debugger
289
290=item * 4 - on startup
291
292=back
293
294=head4 C<$doret>
295
296The value -2 indicates that no return value should be printed.
297Any other positive value causes C<DB::sub> to print return values.
298
299=head4 C<$evalarg>
300
301The item to be eval'ed by C<DB::eval>. Used to prevent messing with the current
302contents of C<@_> when C<DB::eval> is called.
303
304=head4 C<$frame>
305
306Determines what messages (if any) will get printed when a subroutine (or eval)
b570d64b 307is entered or exited.
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308
309=over 4
310
311=item * 0 - No enter/exit messages
312
be9a9b1d 313=item * 1 - Print I<entering> messages on subroutine entry
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314
315=item * 2 - Adds exit messages on subroutine exit. If no other flag is on, acts like 1+2.
316
be9a9b1d 317=item * 4 - Extended messages: C<< <in|out> I<context>=I<fully-qualified sub name> from I<file>:I<line> >>. If no other flag is on, acts like 1+4.
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318
319=item * 8 - Adds parameter information to messages, and overloaded stringify and tied FETCH is enabled on the printed arguments. Ignored if C<4> is not on.
320
321=item * 16 - Adds C<I<context> return from I<subname>: I<value>> messages on subroutine/eval exit. Ignored if C<4> is is not on.
322
323=back
324
be9a9b1d 325To get everything, use C<$frame=30> (or C<o f=30> as a debugger command).
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326The debugger internally juggles the value of C<$frame> during execution to
327protect external modules that the debugger uses from getting traced.
328
329=head4 C<$level>
330
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331Tracks current debugger nesting level. Used to figure out how many
332C<E<lt>E<gt>> pairs to surround the line number with when the debugger
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333outputs a prompt. Also used to help determine if the program has finished
334during command parsing.
335
336=head4 C<$onetimeDump>
337
338Controls what (if anything) C<DB::eval()> will print after evaluating an
339expression.
340
341=over 4
342
343=item * C<undef> - don't print anything
344
345=item * C<dump> - use C<dumpvar.pl> to display the value returned
346
347=item * C<methods> - print the methods callable on the first item returned
348
349=back
350
351=head4 C<$onetimeDumpDepth>
352
be9a9b1d 353Controls how far down C<dumpvar.pl> will go before printing C<...> while
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354dumping a structure. Numeric. If C<undef>, print all levels.
355
356=head4 C<$signal>
357
358Used to track whether or not an C<INT> signal has been detected. C<DB::DB()>,
359which is called before every statement, checks this and puts the user into
360command mode if it finds C<$signal> set to a true value.
361
362=head4 C<$single>
363
364Controls behavior during single-stepping. Stacked in C<@stack> on entry to
365each subroutine; popped again at the end of each subroutine.
366
b570d64b 367=over 4
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368
369=item * 0 - run continuously.
370
be9a9b1d 371=item * 1 - single-step, go into subs. The C<s> command.
69893cff 372
be9a9b1d 373=item * 2 - single-step, don't go into subs. The C<n> command.
69893cff 374
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375=item * 4 - print current sub depth (turned on to force this when C<too much
376recursion> occurs.
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377
378=back
379
380=head4 C<$trace>
381
b570d64b 382Controls the output of trace information.
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383
384=over 4
385
386=item * 1 - The C<t> command was entered to turn on tracing (every line executed is printed)
387
388=item * 2 - watch expressions are active
389
390=item * 4 - user defined a C<watchfunction()> in C<afterinit()>
391
392=back
393
394=head4 C<$slave_editor>
395
3961 if C<LINEINFO> was directed to a pipe; 0 otherwise.
397
398=head4 C<@cmdfhs>
399
400Stack of filehandles that C<DB::readline()> will read commands from.
401Manipulated by the debugger's C<source> command and C<DB::readline()> itself.
402
403=head4 C<@dbline>
404
b570d64b 405Local alias to the magical line array, C<@{$main::{'_<'.$filename}}> ,
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406supplied by the Perl interpreter to the debugger. Contains the source.
407
408=head4 C<@old_watch>
409
410Previous values of watch expressions. First set when the expression is
411entered; reset whenever the watch expression changes.
412
413=head4 C<@saved>
414
415Saves important globals (C<$@>, C<$!>, C<$^E>, C<$,>, C<$/>, C<$\>, C<$^W>)
416so that the debugger can substitute safe values while it's running, and
417restore them when it returns control.
418
419=head4 C<@stack>
420
421Saves the current value of C<$single> on entry to a subroutine.
422Manipulated by the C<c> command to turn off tracing in all subs above the
423current one.
424
425=head4 C<@to_watch>
426
427The 'watch' expressions: to be evaluated before each line is executed.
428
429=head4 C<@typeahead>
430
431The typeahead buffer, used by C<DB::readline>.
432
433=head4 C<%alias>
434
435Command aliases. Stored as character strings to be substituted for a command
436entered.
437
438=head4 C<%break_on_load>
439
440Keys are file names, values are 1 (break when this file is loaded) or undef
441(don't break when it is loaded).
442
443=head4 C<%dbline>
444
be9a9b1d 445Keys are line numbers, values are C<condition\0action>. If used in numeric
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446context, values are 0 if not breakable, 1 if breakable, no matter what is
447in the actual hash entry.
448
449=head4 C<%had_breakpoints>
450
451Keys are file names; values are bitfields:
452
b570d64b 453=over 4
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454
455=item * 1 - file has a breakpoint in it.
456
457=item * 2 - file has an action in it.
458
459=back
460
461A zero or undefined value means this file has neither.
462
463=head4 C<%option>
464
465Stores the debugger options. These are character string values.
466
467=head4 C<%postponed>
468
469Saves breakpoints for code that hasn't been compiled yet.
470Keys are subroutine names, values are:
471
472=over 4
473
be9a9b1d 474=item * C<compile> - break when this sub is compiled
69893cff 475
be9a9b1d 476=item * C<< break +0 if <condition> >> - break (conditionally) at the start of this routine. The condition will be '1' if no condition was specified.
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477
478=back
479
480=head4 C<%postponed_file>
481
482This hash keeps track of breakpoints that need to be set for files that have
483not yet been compiled. Keys are filenames; values are references to hashes.
484Each of these hashes is keyed by line number, and its values are breakpoint
be9a9b1d 485definitions (C<condition\0action>).
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486
487=head1 DEBUGGER INITIALIZATION
488
489The debugger's initialization actually jumps all over the place inside this
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490package. This is because there are several BEGIN blocks (which of course
491execute immediately) spread through the code. Why is that?
69893cff 492
b570d64b 493The debugger needs to be able to change some things and set some things up
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494before the debugger code is compiled; most notably, the C<$deep> variable that
495C<DB::sub> uses to tell when a program has recursed deeply. In addition, the
496debugger has to turn off warnings while the debugger code is compiled, but then
497restore them to their original setting before the program being debugged begins
498executing.
499
500The first C<BEGIN> block simply turns off warnings by saving the current
501setting of C<$^W> and then setting it to zero. The second one initializes
502the debugger variables that are needed before the debugger begins executing.
b570d64b 503The third one puts C<$^X> back to its former value.
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504
505We'll detail the second C<BEGIN> block later; just remember that if you need
506to initialize something before the debugger starts really executing, that's
507where it has to go.
508
509=cut
510
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511package DB;
512
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513use strict;
514
2dbd01ad 515BEGIN {eval 'use IO::Handle'}; # Needed for flush only? breaks under miniperl
9eba6a4e 516
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517BEGIN {
518 require feature;
519 $^V =~ /^v(\d+\.\d+)/;
520 feature->import(":$1");
521}
522
54d04a52 523# Debugger for Perl 5.00x; perl5db.pl patch level:
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524use vars qw($VERSION $header);
525
931d9438 526$VERSION = '1.39_05';
69893cff 527
e22ea7cc 528$header = "perl5db.pl version $VERSION";
d338d6fe 529
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530=head1 DEBUGGER ROUTINES
531
532=head2 C<DB::eval()>
533
534This function replaces straight C<eval()> inside the debugger; it simplifies
535the process of evaluating code in the user's context.
536
b570d64b 537The code to be evaluated is passed via the package global variable
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538C<$DB::evalarg>; this is done to avoid fiddling with the contents of C<@_>.
539
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540Before we do the C<eval()>, we preserve the current settings of C<$trace>,
541C<$single>, C<$^D> and C<$usercontext>. The latter contains the
542preserved values of C<$@>, C<$!>, C<$^E>, C<$,>, C<$/>, C<$\>, C<$^W> and the
543user's current package, grabbed when C<DB::DB> got control. This causes the
544proper context to be used when the eval is actually done. Afterward, we
545restore C<$trace>, C<$single>, and C<$^D>.
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546
547Next we need to handle C<$@> without getting confused. We save C<$@> in a
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548local lexical, localize C<$saved[0]> (which is where C<save()> will put
549C<$@>), and then call C<save()> to capture C<$@>, C<$!>, C<$^E>, C<$,>,
69893cff 550C<$/>, C<$\>, and C<$^W>) and set C<$,>, C<$/>, C<$\>, and C<$^W> to values
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551considered sane by the debugger. If there was an C<eval()> error, we print
552it on the debugger's output. If C<$onetimedump> is defined, we call
553C<dumpit> if it's set to 'dump', or C<methods> if it's set to
554'methods'. Setting it to something else causes the debugger to do the eval
555but not print the result - handy if you want to do something else with it
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556(the "watch expressions" code does this to get the value of the watch
557expression but not show it unless it matters).
558
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559In any case, we then return the list of output from C<eval> to the caller,
560and unwinding restores the former version of C<$@> in C<@saved> as well
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561(the localization of C<$saved[0]> goes away at the end of this scope).
562
563=head3 Parameters and variables influencing execution of DB::eval()
564
565C<DB::eval> isn't parameterized in the standard way; this is to keep the
566debugger's calls to C<DB::eval()> from mucking with C<@_>, among other things.
b570d64b 567The variables listed below influence C<DB::eval()>'s execution directly.
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568
569=over 4
570
571=item C<$evalarg> - the thing to actually be eval'ed
572
be9a9b1d 573=item C<$trace> - Current state of execution tracing
69893cff 574
be9a9b1d 575=item C<$single> - Current state of single-stepping
69893cff 576
b570d64b 577=item C<$onetimeDump> - what is to be displayed after the evaluation
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578
579=item C<$onetimeDumpDepth> - how deep C<dumpit()> should go when dumping results
580
581=back
582
583The following variables are altered by C<DB::eval()> during its execution. They
b570d64b 584are "stacked" via C<local()>, enabling recursive calls to C<DB::eval()>.
69893cff
RGS
585
586=over 4
587
588=item C<@res> - used to capture output from actual C<eval>.
589
590=item C<$otrace> - saved value of C<$trace>.
591
b570d64b 592=item C<$osingle> - saved value of C<$single>.
69893cff
RGS
593
594=item C<$od> - saved value of C<$^D>.
595
596=item C<$saved[0]> - saved value of C<$@>.
597
b570d64b 598=item $\ - for output of C<$@> if there is an evaluation error.
69893cff
RGS
599
600=back
601
602=head3 The problem of lexicals
603
604The context of C<DB::eval()> presents us with some problems. Obviously,
605we want to be 'sandboxed' away from the debugger's internals when we do
606the eval, but we need some way to control how punctuation variables and
b570d64b 607debugger globals are used.
69893cff
RGS
608
609We can't use local, because the code inside C<DB::eval> can see localized
610variables; and we can't use C<my> either for the same reason. The code
611in this routine compromises and uses C<my>.
612
613After this routine is over, we don't have user code executing in the debugger's
614context, so we can use C<my> freely.
615
616=cut
617
618############################################## Begin lexical danger zone
619
620# 'my' variables used here could leak into (that is, be visible in)
621# the context that the code being evaluated is executing in. This means that
622# the code could modify the debugger's variables.
623#
624# Fiddling with the debugger's context could be Bad. We insulate things as
625# much as we can.
626
6b24a4b7
SF
627use vars qw(
628 @args
629 %break_on_load
630 @cmdfhs
631 $CommandSet
632 $CreateTTY
633 $DBGR
634 @dbline
635 $dbline
636 %dbline
637 $dieLevel
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)
22fc883d 702 return 'no strict; ($@, $!, $^E, $,, $/, $\, $^W) = @DB::saved;'
6b24a4b7
SF
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 $@
7c54f46a 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
2dbd01ad 836 [tid] DB<$i>
2cbb2ee1
RGS
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 {
2dbd01ad
SF
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 }
2cbb2ee1
RGS
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)) {
2dbd01ad 894 share(\$main::{'_<'.$filename}) if defined $filename;
2cbb2ee1
RGS
895};
896
54d04a52 897# Command-line + PERLLIB:
69893cff 898# Save the contents of @INC before they are modified elsewhere.
54d04a52
IZ
899@ini_INC = @INC;
900
69893cff
RGS
901# This was an attempt to clear out the previous values of various
902# trapped errors. Apparently it didn't help. XXX More info needed!
d338d6fe
PP
903# $prevwarn = $prevdie = $prevbus = $prevsegv = ''; # Does not help?!
904
69893cff
RGS
905# We set these variables to safe values. We don't want to blindly turn
906# off warnings, because other packages may still want them.
e22ea7cc
RF
907$trace = $signal = $single = 0; # Uninitialized warning suppression
908 # (local $^W cannot help - other packages!).
69893cff
RGS
909
910# Default to not exiting when program finishes; print the return
911# value when the 'r' command is used to return from a subroutine.
55497cff 912$inhibit_exit = $option{PrintRet} = 1;
d338d6fe 913
6b24a4b7
SF
914use vars qw($trace_to_depth);
915
5e2b42dd
SF
916# Default to 1E9 so it won't be limited to a certain recursion depth.
917$trace_to_depth = 1E9;
bdba49ad 918
69893cff
RGS
919=head1 OPTION PROCESSING
920
b570d64b
SF
921The debugger's options are actually spread out over the debugger itself and
922C<dumpvar.pl>; some of these are variables to be set, while others are
69893cff
RGS
923subs to be called with a value. To try to make this a little easier to
924manage, the debugger uses a few data structures to define what options
925are legal and how they are to be processed.
926
927First, the C<@options> array defines the I<names> of all the options that
928are to be accepted.
929
930=cut
931
932@options = qw(
5561b870 933 CommandSet HistFile HistSize
e22ea7cc
RF
934 hashDepth arrayDepth dumpDepth
935 DumpDBFiles DumpPackages DumpReused
936 compactDump veryCompact quote
937 HighBit undefPrint globPrint
938 PrintRet UsageOnly frame
939 AutoTrace TTY noTTY
940 ReadLine NonStop LineInfo
941 maxTraceLen recallCommand ShellBang
942 pager tkRunning ornaments
943 signalLevel warnLevel dieLevel
944 inhibit_exit ImmediateStop bareStringify
945 CreateTTY RemotePort windowSize
584420f0 946 DollarCaretP
e22ea7cc 947);
d12a4851 948
584420f0 949@RememberOnROptions = qw(DollarCaretP);
d12a4851 950
69893cff
RGS
951=pod
952
953Second, C<optionVars> lists the variables that each option uses to save its
954state.
955
956=cut
957
6b24a4b7
SF
958use vars qw(%optionVars);
959
69893cff 960%optionVars = (
e22ea7cc
RF
961 hashDepth => \$dumpvar::hashDepth,
962 arrayDepth => \$dumpvar::arrayDepth,
963 CommandSet => \$CommandSet,
964 DumpDBFiles => \$dumpvar::dumpDBFiles,
965 DumpPackages => \$dumpvar::dumpPackages,
966 DumpReused => \$dumpvar::dumpReused,
967 HighBit => \$dumpvar::quoteHighBit,
968 undefPrint => \$dumpvar::printUndef,
969 globPrint => \$dumpvar::globPrint,
970 UsageOnly => \$dumpvar::usageOnly,
971 CreateTTY => \$CreateTTY,
972 bareStringify => \$dumpvar::bareStringify,
973 frame => \$frame,
974 AutoTrace => \$trace,
975 inhibit_exit => \$inhibit_exit,
976 maxTraceLen => \$maxtrace,
977 ImmediateStop => \$ImmediateStop,
978 RemotePort => \$remoteport,
979 windowSize => \$window,
5561b870
AK
980 HistFile => \$histfile,
981 HistSize => \$histsize,
69893cff
RGS
982);
983
984=pod
985
986Third, C<%optionAction> defines the subroutine to be called to process each
987option.
988
b570d64b 989=cut
69893cff 990
6b24a4b7
SF
991use vars qw(%optionAction);
992
69893cff
RGS
993%optionAction = (
994 compactDump => \&dumpvar::compactDump,
995 veryCompact => \&dumpvar::veryCompact,
996 quote => \&dumpvar::quote,
997 TTY => \&TTY,
998 noTTY => \&noTTY,
999 ReadLine => \&ReadLine,
1000 NonStop => \&NonStop,
1001 LineInfo => \&LineInfo,
1002 recallCommand => \&recallCommand,
1003 ShellBang => \&shellBang,
1004 pager => \&pager,
1005 signalLevel => \&signalLevel,
1006 warnLevel => \&warnLevel,
1007 dieLevel => \&dieLevel,
1008 tkRunning => \&tkRunning,
1009 ornaments => \&ornaments,
1010 RemotePort => \&RemotePort,
1011 DollarCaretP => \&DollarCaretP,
d12a4851
JH
1012);
1013
69893cff
RGS
1014=pod
1015
1016Last, the C<%optionRequire> notes modules that must be C<require>d if an
1017option is used.
1018
1019=cut
d338d6fe 1020
69893cff
RGS
1021# Note that this list is not complete: several options not listed here
1022# actually require that dumpvar.pl be loaded for them to work, but are
1023# not in the table. A subsequent patch will correct this problem; for
1024# the moment, we're just recommenting, and we are NOT going to change
1025# function.
6b24a4b7
SF
1026use vars qw(%optionRequire);
1027
eda6e075 1028%optionRequire = (
69893cff
RGS
1029 compactDump => 'dumpvar.pl',
1030 veryCompact => 'dumpvar.pl',
1031 quote => 'dumpvar.pl',
e22ea7cc 1032);
69893cff
RGS
1033
1034=pod
1035
1036There are a number of initialization-related variables which can be set
1037by putting code to set them in a BEGIN block in the C<PERL5DB> environment
1038variable. These are:
1039
1040=over 4
1041
1042=item C<$rl> - readline control XXX needs more explanation
1043
1044=item C<$warnLevel> - whether or not debugger takes over warning handling
1045
1046=item C<$dieLevel> - whether or not debugger takes over die handling
1047
1048=item C<$signalLevel> - whether or not debugger takes over signal handling
1049
1050=item C<$pre> - preprompt actions (array reference)
1051
1052=item C<$post> - postprompt actions (array reference)
1053
1054=item C<$pretype>
1055
1056=item C<$CreateTTY> - whether or not to create a new TTY for this debugger
1057
1058=item C<$CommandSet> - which command set to use (defaults to new, documented set)
1059
1060=back
1061
1062=cut
d338d6fe
PP
1063
1064# These guys may be defined in $ENV{PERL5DB} :
69893cff
RGS
1065$rl = 1 unless defined $rl;
1066$warnLevel = 1 unless defined $warnLevel;
1067$dieLevel = 1 unless defined $dieLevel;
1068$signalLevel = 1 unless defined $signalLevel;
1069$pre = [] unless defined $pre;
1070$post = [] unless defined $post;
1071$pretype = [] unless defined $pretype;
1072$CreateTTY = 3 unless defined $CreateTTY;
1073$CommandSet = '580' unless defined $CommandSet;
1074
2cbb2ee1
RGS
1075share($rl);
1076share($warnLevel);
1077share($dieLevel);
1078share($signalLevel);
1079share($pre);
1080share($post);
1081share($pretype);
1082share($rl);
1083share($CreateTTY);
1084share($CommandSet);
1085
69893cff
RGS
1086=pod
1087
1088The default C<die>, C<warn>, and C<signal> handlers are set up.
1089
1090=cut
055fd3a9 1091
d338d6fe
PP
1092warnLevel($warnLevel);
1093dieLevel($dieLevel);
1094signalLevel($signalLevel);
055fd3a9 1095
69893cff
RGS
1096=pod
1097
1098The pager to be used is needed next. We try to get it from the
5561b870 1099environment first. If it's not defined there, we try to find it in
69893cff
RGS
1100the Perl C<Config.pm>. If it's not there, we default to C<more>. We
1101then call the C<pager()> function to save the pager name.
1102
1103=cut
1104
1105# This routine makes sure $pager is set up so that '|' can use it.
4865a36d 1106pager(
e22ea7cc 1107
69893cff 1108 # If PAGER is defined in the environment, use it.
e22ea7cc
RF
1109 defined $ENV{PAGER}
1110 ? $ENV{PAGER}
69893cff
RGS
1111
1112 # If not, see if Config.pm defines it.
e22ea7cc
RF
1113 : eval { require Config }
1114 && defined $Config::Config{pager}
1115 ? $Config::Config{pager}
69893cff
RGS
1116
1117 # If not, fall back to 'more'.
e22ea7cc
RF
1118 : 'more'
1119 )
1120 unless defined $pager;
69893cff
RGS
1121
1122=pod
1123
1124We set up the command to be used to access the man pages, the command
be9a9b1d
AT
1125recall character (C<!> unless otherwise defined) and the shell escape
1126character (C<!> unless otherwise defined). Yes, these do conflict, and
69893cff
RGS
1127neither works in the debugger at the moment.
1128
1129=cut
1130
055fd3a9 1131setman();
69893cff
RGS
1132
1133# Set up defaults for command recall and shell escape (note:
1134# these currently don't work in linemode debugging).
2218c045
SF
1135recallCommand("!") unless defined $prc;
1136shellBang("!") unless defined $psh;
69893cff
RGS
1137
1138=pod
1139
1140We then set up the gigantic string containing the debugger help.
1141We also set the limit on the number of arguments we'll display during a
1142trace.
1143
1144=cut
1145
04e43a21 1146sethelp();
69893cff
RGS
1147
1148# If we didn't get a default for the length of eval/stack trace args,
1149# set it here.
1d06cb2d 1150$maxtrace = 400 unless defined $maxtrace;
69893cff
RGS
1151
1152=head2 SETTING UP THE DEBUGGER GREETING
1153
be9a9b1d 1154The debugger I<greeting> helps to inform the user how many debuggers are
69893cff
RGS
1155running, and whether the current debugger is the primary or a child.
1156
1157If we are the primary, we just hang onto our pid so we'll have it when
1158or if we start a child debugger. If we are a child, we'll set things up
1159so we'll have a unique greeting and so the parent will give us our own
1160TTY later.
1161
1162We save the current contents of the C<PERLDB_PIDS> environment variable
1163because we mess around with it. We'll also need to hang onto it because
1164we'll need it if we restart.
1165
1166Child debuggers make a label out of the current PID structure recorded in
1167PERLDB_PIDS plus the new PID. They also mark themselves as not having a TTY
1168yet so the parent will give them one later via C<resetterm()>.
1169
1170=cut
1171
e22ea7cc 1172# Save the current contents of the environment; we're about to
69893cff 1173# much with it. We'll need this if we have to restart.
6b24a4b7 1174use vars qw($ini_pids);
f1583d8f 1175$ini_pids = $ENV{PERLDB_PIDS};
69893cff 1176
6b24a4b7
SF
1177use vars qw ($pids $term_pid);
1178
e22ea7cc
RF
1179if ( defined $ENV{PERLDB_PIDS} ) {
1180
69893cff 1181 # We're a child. Make us a label out of the current PID structure
e22ea7cc 1182 # recorded in PERLDB_PIDS plus our (new) PID. Mark us as not having
69893cff 1183 # a term yet so the parent will give us one later via resetterm().
55f4245e
JM
1184
1185 my $env_pids = $ENV{PERLDB_PIDS};
1186 $pids = "[$env_pids]";
1187
1188 # Unless we are on OpenVMS, all programs under the DCL shell run under
1189 # the same PID.
1190
1191 if (($^O eq 'VMS') && ($env_pids =~ /\b$$\b/)) {
1192 $term_pid = $$;
1193 }
1194 else {
1195 $ENV{PERLDB_PIDS} .= "->$$";
1196 $term_pid = -1;
1197 }
1198
69893cff
RGS
1199} ## end if (defined $ENV{PERLDB_PIDS...
1200else {
e22ea7cc
RF
1201
1202 # We're the parent PID. Initialize PERLDB_PID in case we end up with a
69893cff
RGS
1203 # child debugger, and mark us as the parent, so we'll know to set up
1204 # more TTY's is we have to.
1205 $ENV{PERLDB_PIDS} = "$$";
619a0444 1206 $pids = "[pid=$$]";
e22ea7cc 1207 $term_pid = $$;
f1583d8f 1208}
69893cff 1209
6b24a4b7 1210use vars qw($pidprompt);
f1583d8f 1211$pidprompt = '';
69893cff
RGS
1212
1213# Sets up $emacs as a synonym for $slave_editor.
6b24a4b7 1214use vars qw($slave_editor);
69893cff
RGS
1215*emacs = $slave_editor if $slave_editor; # May be used in afterinit()...
1216
1217=head2 READING THE RC FILE
1218
b570d64b 1219The debugger will read a file of initialization options if supplied. If
69893cff
RGS
1220running interactively, this is C<.perldb>; if not, it's C<perldb.ini>.
1221
b570d64b 1222=cut
69893cff
RGS
1223
1224# As noted, this test really doesn't check accurately that the debugger
1225# is running at a terminal or not.
d338d6fe 1226
6b24a4b7 1227use vars qw($rcfile);
fb4d8a6c
SF
1228{
1229 my $dev_tty = (($^O eq 'VMS') ? 'TT:' : '/dev/tty');
1230 # this is the wrong metric!
1231 $rcfile = ((-e $dev_tty) ? ".perldb" : "perldb.ini");
d338d6fe
PP
1232}
1233
69893cff
RGS
1234=pod
1235
1236The debugger does a safety test of the file to be read. It must be owned
1237either by the current user or root, and must only be writable by the owner.
1238
1239=cut
1240
1241# This wraps a safety test around "do" to read and evaluate the init file.
1242#
055fd3a9
GS
1243# This isn't really safe, because there's a race
1244# between checking and opening. The solution is to
1245# open and fstat the handle, but then you have to read and
1246# eval the contents. But then the silly thing gets
69893cff
RGS
1247# your lexical scope, which is unfortunate at best.
1248sub safe_do {
055fd3a9
GS
1249 my $file = shift;
1250
1251 # Just exactly what part of the word "CORE::" don't you understand?
69893cff
RGS
1252 local $SIG{__WARN__};
1253 local $SIG{__DIE__};
055fd3a9 1254
e22ea7cc 1255 unless ( is_safe_file($file) ) {
69893cff 1256 CORE::warn <<EO_GRIPE;
055fd3a9 1257perldb: Must not source insecure rcfile $file.
b570d64b 1258 You or the superuser must be the owner, and it must not
69893cff 1259 be writable by anyone but its owner.
055fd3a9 1260EO_GRIPE
69893cff
RGS
1261 return;
1262 } ## end unless (is_safe_file($file...
055fd3a9
GS
1263
1264 do $file;
1265 CORE::warn("perldb: couldn't parse $file: $@") if $@;
69893cff 1266} ## end sub safe_do
055fd3a9 1267
69893cff
RGS
1268# This is the safety test itself.
1269#
055fd3a9
GS
1270# Verifies that owner is either real user or superuser and that no
1271# one but owner may write to it. This function is of limited use
1272# when called on a path instead of upon a handle, because there are
1273# no guarantees that filename (by dirent) whose file (by ino) is
e22ea7cc 1274# eventually accessed is the same as the one tested.
055fd3a9
GS
1275# Assumes that the file's existence is not in doubt.
1276sub is_safe_file {
1277 my $path = shift;
69893cff 1278 stat($path) || return; # mysteriously vaporized
e22ea7cc 1279 my ( $dev, $ino, $mode, $nlink, $uid, $gid ) = stat(_);
055fd3a9
GS
1280
1281 return 0 if $uid != 0 && $uid != $<;
1282 return 0 if $mode & 022;
1283 return 1;
69893cff 1284} ## end sub is_safe_file
055fd3a9 1285
69893cff 1286# If the rcfile (whichever one we decided was the right one to read)
e22ea7cc
RF
1287# exists, we safely do it.
1288if ( -f $rcfile ) {
055fd3a9 1289 safe_do("./$rcfile");
69893cff 1290}
e22ea7cc 1291
69893cff 1292# If there isn't one here, try the user's home directory.
e22ea7cc 1293elsif ( defined $ENV{HOME} && -f "$ENV{HOME}/$rcfile" ) {
055fd3a9
GS
1294 safe_do("$ENV{HOME}/$rcfile");
1295}
e22ea7cc 1296
69893cff 1297# Else try the login directory.
e22ea7cc 1298elsif ( defined $ENV{LOGDIR} && -f "$ENV{LOGDIR}/$rcfile" ) {
055fd3a9 1299 safe_do("$ENV{LOGDIR}/$rcfile");
d338d6fe
PP
1300}
1301
69893cff 1302# If the PERLDB_OPTS variable has options in it, parse those out next.
e22ea7cc
RF
1303if ( defined $ENV{PERLDB_OPTS} ) {
1304 parse_options( $ENV{PERLDB_OPTS} );
d338d6fe
PP
1305}
1306
69893cff
RGS
1307=pod
1308
1309The last thing we do during initialization is determine which subroutine is
1310to be used to obtain a new terminal when a new debugger is started. Right now,
b0b54b5e 1311the debugger only handles TCP sockets, X11, OS/2, amd Mac OS X
11653f7f 1312(darwin).
69893cff
RGS
1313
1314=cut
1315
1316# Set up the get_fork_TTY subroutine to be aliased to the proper routine.
1317# Works if you're running an xterm or xterm-like window, or you're on
6fae1ad7
RF
1318# OS/2, or on Mac OS X. This may need some expansion.
1319
1320if (not defined &get_fork_TTY) # only if no routine exists
69893cff 1321{
b570d64b 1322 if ( defined $remoteport ) {
11653f7f
JJ
1323 # Expect an inetd-like server
1324 *get_fork_TTY = \&socket_get_fork_TTY; # to listen to us
1325 }
1326 elsif (defined $ENV{TERM} # If we know what kind
6fae1ad7
RF
1327 # of terminal this is,
1328 and $ENV{TERM} eq 'xterm' # and it's an xterm,
1329 and defined $ENV{DISPLAY} # and what display it's on,
1330 )
1331 {
1332 *get_fork_TTY = \&xterm_get_fork_TTY; # use the xterm version
1333 }
1334 elsif ( $^O eq 'os2' ) { # If this is OS/2,
1335 *get_fork_TTY = \&os2_get_fork_TTY; # use the OS/2 version
1336 }
1337 elsif ( $^O eq 'darwin' # If this is Mac OS X
1338 and defined $ENV{TERM_PROGRAM} # and we're running inside
1339 and $ENV{TERM_PROGRAM}
1340 eq 'Apple_Terminal' # Terminal.app
1341 )
1342 {
1343 *get_fork_TTY = \&macosx_get_fork_TTY; # use the Mac OS X version
1344 }
69893cff 1345} ## end if (not defined &get_fork_TTY...
e22ea7cc 1346
dbb46cec
DQ
1347# untaint $^O, which may have been tainted by the last statement.
1348# see bug [perl #24674]
e22ea7cc
RF
1349$^O =~ m/^(.*)\z/;
1350$^O = $1;
f1583d8f 1351
d12a4851 1352# Here begin the unreadable code. It needs fixing.
055fd3a9 1353
69893cff
RGS
1354=head2 RESTART PROCESSING
1355
1356This section handles the restart command. When the C<R> command is invoked, it
1357tries to capture all of the state it can into environment variables, and
1358then sets C<PERLDB_RESTART>. When we start executing again, we check to see
1359if C<PERLDB_RESTART> is there; if so, we reload all the information that
1360the R command stuffed into the environment variables.
1361
b570d64b 1362 PERLDB_RESTART - flag only, contains no restart data itself.
69893cff
RGS
1363 PERLDB_HIST - command history, if it's available
1364 PERLDB_ON_LOAD - breakpoints set by the rc file
1365 PERLDB_POSTPONE - subs that have been loaded/not executed, and have actions
1366 PERLDB_VISITED - files that had breakpoints
1367 PERLDB_FILE_... - breakpoints for a file
1368 PERLDB_OPT - active options
1369 PERLDB_INC - the original @INC
1370 PERLDB_PRETYPE - preprompt debugger actions
1371 PERLDB_PRE - preprompt Perl code
1372 PERLDB_POST - post-prompt Perl code
1373 PERLDB_TYPEAHEAD - typeahead captured by readline()
1374
1375We chug through all these variables and plug the values saved in them
1376back into the appropriate spots in the debugger.
1377
1378=cut
1379
6b24a4b7
SF
1380use vars qw(@hist @truehist %postponed_file @typeahead);
1381
fb0fb5f4
SF
1382sub _restore_shared_globals_after_restart
1383{
1384 @hist = get_list('PERLDB_HIST');
1385 %break_on_load = get_list("PERLDB_ON_LOAD");
1386 %postponed = get_list("PERLDB_POSTPONE");
1387
1388 share(@hist);
1389 share(@truehist);
1390 share(%break_on_load);
1391 share(%postponed);
1392}
1393
e18a02a6 1394sub _restore_breakpoints_and_actions {
e22ea7cc 1395
e22ea7cc 1396 my @had_breakpoints = get_list("PERLDB_VISITED");
e18a02a6 1397
bdba49ad
SF
1398 for my $file_idx ( 0 .. $#had_breakpoints ) {
1399 my $filename = $had_breakpoints[$file_idx];
1400 my %pf = get_list("PERLDB_FILE_$file_idx");
1401 $postponed_file{ $filename } = \%pf if %pf;
1402 my @lines = sort {$a <=> $b} keys(%pf);
1403 my @enabled_statuses = get_list("PERLDB_FILE_ENABLED_$file_idx");
1404 for my $line_idx (0 .. $#lines) {
1405 _set_breakpoint_enabled_status(
1406 $filename,
1407 $lines[$line_idx],
1408 ($enabled_statuses[$line_idx] ? 1 : ''),
1409 );
1410 }
e22ea7cc 1411 }
69893cff 1412
e18a02a6
SF
1413 return;
1414}
1415
ca50076b
SF
1416sub _restore_options_after_restart
1417{
1418 my %options_map = get_list("PERLDB_OPT");
1419
1420 while ( my ( $opt, $val ) = each %options_map ) {
1421 $val =~ s/[\\\']/\\$1/g;
1422 parse_options("$opt'$val'");
1423 }
1424
1425 return;
1426}
1427
18580168
SF
1428sub _restore_globals_after_restart
1429{
1430 # restore original @INC
1431 @INC = get_list("PERLDB_INC");
1432 @ini_INC = @INC;
1433
1434 # return pre/postprompt actions and typeahead buffer
1435 $pretype = [ get_list("PERLDB_PRETYPE") ];
1436 $pre = [ get_list("PERLDB_PRE") ];
1437 $post = [ get_list("PERLDB_POST") ];
1438 @typeahead = get_list( "PERLDB_TYPEAHEAD", @typeahead );
1439
1440 return;
1441}
1442
fb0fb5f4 1443
e18a02a6
SF
1444if ( exists $ENV{PERLDB_RESTART} ) {
1445
1446 # We're restarting, so we don't need the flag that says to restart anymore.
1447 delete $ENV{PERLDB_RESTART};
1448
1449 # $restart = 1;
fb0fb5f4 1450 _restore_shared_globals_after_restart();
e18a02a6
SF
1451
1452 _restore_breakpoints_and_actions();
1453
69893cff 1454 # restore options
ca50076b 1455 _restore_options_after_restart();
69893cff 1456
18580168 1457 _restore_globals_after_restart();
69893cff
RGS
1458} ## end if (exists $ENV{PERLDB_RESTART...
1459
1460=head2 SETTING UP THE TERMINAL
1461
1462Now, we'll decide how the debugger is going to interact with the user.
1463If there's no TTY, we set the debugger to run non-stop; there's not going
1464to be anyone there to enter commands.
1465
1466=cut
54d04a52 1467
6b24a4b7
SF
1468use vars qw($notty $runnonstop $console $tty $LINEINFO);
1469use vars qw($lineinfo $doccmd);
1470
d338d6fe 1471if ($notty) {
69893cff 1472 $runnonstop = 1;
2dbd01ad 1473 share($runnonstop);
69893cff 1474}
d12a4851 1475
69893cff
RGS
1476=pod
1477
1478If there is a TTY, we have to determine who it belongs to before we can
1479proceed. If this is a slave editor or graphical debugger (denoted by
1480the first command-line switch being '-emacs'), we shift this off and
1481set C<$rl> to 0 (XXX ostensibly to do straight reads).
1482
1483=cut
1484
1485else {
e22ea7cc 1486
69893cff
RGS
1487 # Is Perl being run from a slave editor or graphical debugger?
1488 # If so, don't use readline, and set $slave_editor = 1.
2b0b9dd1
SF
1489 if ($slave_editor = ( @main::ARGV && ( $main::ARGV[0] eq '-emacs' ) )) {
1490 $rl = 0;
1491 shift(@main::ARGV);
1492 }
e22ea7cc
RF
1493
1494 #require Term::ReadLine;
d12a4851 1495
69893cff
RGS
1496=pod
1497
1498We then determine what the console should be on various systems:
1499
1500=over 4
1501
1502=item * Cygwin - We use C<stdin> instead of a separate device.
1503
1504=cut
1505
e22ea7cc
RF
1506 if ( $^O eq 'cygwin' ) {
1507
69893cff
RGS
1508 # /dev/tty is binary. use stdin for textmode
1509 undef $console;
1510 }
1511
1512=item * Unix - use C</dev/tty>.
1513
1514=cut
1515
e22ea7cc 1516 elsif ( -e "/dev/tty" ) {
69893cff
RGS
1517 $console = "/dev/tty";
1518 }
1519
1520=item * Windows or MSDOS - use C<con>.
1521
1522=cut
1523
e22ea7cc 1524 elsif ( $^O eq 'dos' or -e "con" or $^O eq 'MSWin32' ) {
69893cff
RGS
1525 $console = "con";
1526 }
1527
69893cff
RGS
1528=item * VMS - use C<sys$command>.
1529
1530=cut
1531
1532 else {
e22ea7cc 1533
69893cff
RGS
1534 # everything else is ...
1535 $console = "sys\$command";
d12a4851 1536 }
69893cff
RGS
1537
1538=pod
1539
1540=back
1541
1542Several other systems don't use a specific console. We C<undef $console>
1543for those (Windows using a slave editor/graphical debugger, NetWare, OS/2
1544with a slave editor, Epoc).
1545
1546=cut
d12a4851 1547
e22ea7cc
RF
1548 if ( ( $^O eq 'MSWin32' ) and ( $slave_editor or defined $ENV{EMACS} ) ) {
1549
69893cff 1550 # /dev/tty is binary. use stdin for textmode
e22ea7cc
RF
1551 $console = undef;
1552 }
1553
1554 if ( $^O eq 'NetWare' ) {
d12a4851 1555
69893cff
RGS
1556 # /dev/tty is binary. use stdin for textmode
1557 $console = undef;
1558 }
d12a4851 1559
69893cff
RGS
1560 # In OS/2, we need to use STDIN to get textmode too, even though
1561 # it pretty much looks like Unix otherwise.
e22ea7cc
RF
1562 if ( defined $ENV{OS2_SHELL} and ( $slave_editor or $ENV{WINDOWID} ) )
1563 { # In OS/2
1564 $console = undef;
1565 }
1566
1567 # EPOC also falls into the 'got to use STDIN' camp.
1568 if ( $^O eq 'epoc' ) {
1569 $console = undef;
1570 }
d12a4851 1571
69893cff
RGS
1572=pod
1573
1574If there is a TTY hanging around from a parent, we use that as the console.
1575
1576=cut
1577
e22ea7cc 1578 $console = $tty if defined $tty;
d12a4851 1579
b570d64b 1580=head2 SOCKET HANDLING
69893cff
RGS
1581
1582The debugger is capable of opening a socket and carrying out a debugging
1583session over the socket.
1584
1585If C<RemotePort> was defined in the options, the debugger assumes that it
1586should try to start a debugging session on that port. It builds the socket
1587and then tries to connect the input and output filehandles to it.
1588
1589=cut
1590
1591 # Handle socket stuff.
e22ea7cc
RF
1592
1593 if ( defined $remoteport ) {
1594
69893cff
RGS
1595 # If RemotePort was defined in the options, connect input and output
1596 # to the socket.
11653f7f 1597 $IN = $OUT = connect_remoteport();
69893cff
RGS
1598 } ## end if (defined $remoteport)
1599
1600=pod
1601
1602If no C<RemotePort> was defined, and we want to create a TTY on startup,
1603this is probably a situation where multiple debuggers are running (for example,
1604a backticked command that starts up another debugger). We create a new IN and
1605OUT filehandle, and do the necessary mojo to create a new TTY if we know how
1606and if we can.
1607
1608=cut
1609
1610 # Non-socket.
1611 else {
e22ea7cc 1612
69893cff
RGS
1613 # Two debuggers running (probably a system or a backtick that invokes
1614 # the debugger itself under the running one). create a new IN and OUT
e22ea7cc 1615 # filehandle, and do the necessary mojo to create a new tty if we
69893cff 1616 # know how, and we can.
e22ea7cc
RF
1617 create_IN_OUT(4) if $CreateTTY & 4;
1618 if ($console) {
1619
69893cff 1620 # If we have a console, check to see if there are separate ins and
cd1191f1 1621 # outs to open. (They are assumed identical if not.)
69893cff 1622
e22ea7cc
RF
1623 my ( $i, $o ) = split /,/, $console;
1624 $o = $i unless defined $o;
69893cff 1625
69893cff 1626 # read/write on in, or just read, or read on STDIN.
e22ea7cc
RF
1627 open( IN, "+<$i" )
1628 || open( IN, "<$i" )
1629 || open( IN, "<&STDIN" );
1630
69893cff
RGS
1631 # read/write/create/clobber out, or write/create/clobber out,
1632 # or merge with STDERR, or merge with STDOUT.
e22ea7cc
RF
1633 open( OUT, "+>$o" )
1634 || open( OUT, ">$o" )
1635 || open( OUT, ">&STDERR" )
1636 || open( OUT, ">&STDOUT" ); # so we don't dongle stdout
1637
1638 } ## end if ($console)
1639 elsif ( not defined $console ) {
1640
1641 # No console. Open STDIN.
1642 open( IN, "<&STDIN" );
1643
1644 # merge with STDERR, or with STDOUT.
1645 open( OUT, ">&STDERR" )
1646 || open( OUT, ">&STDOUT" ); # so we don't dongle stdout
1647 $console = 'STDIN/OUT';
69893cff
RGS
1648 } ## end elsif (not defined $console)
1649
1650 # Keep copies of the filehandles so that when the pager runs, it
1651 # can close standard input without clobbering ours.
2b0b9dd1
SF
1652 if ($console or (not defined($console))) {
1653 $IN = \*IN;
1654 $OUT = \*OUT;
1655 }
e22ea7cc
RF
1656 } ## end elsif (from if(defined $remoteport))
1657
1658 # Unbuffer DB::OUT. We need to see responses right away.
70c9432b 1659 $OUT->autoflush(1);
e22ea7cc
RF
1660
1661 # Line info goes to debugger output unless pointed elsewhere.
1662 # Pointing elsewhere makes it possible for slave editors to
1663 # keep track of file and position. We have both a filehandle
1664 # and a I/O description to keep track of.
1665 $LINEINFO = $OUT unless defined $LINEINFO;
1666 $lineinfo = $console unless defined $lineinfo;
2dbd01ad
SF
1667 # share($LINEINFO); # <- unable to share globs
1668 share($lineinfo); #
e22ea7cc 1669
69893cff
RGS
1670=pod
1671
1672To finish initialization, we show the debugger greeting,
1673and then call the C<afterinit()> subroutine if there is one.
1674
1675=cut
d12a4851 1676
e22ea7cc
RF
1677 # Show the debugger greeting.
1678 $header =~ s/.Header: ([^,]+),v(\s+\S+\s+\S+).*$/$1$2/;
1679 unless ($runnonstop) {
1680 local $\ = '';
1681 local $, = '';
1682 if ( $term_pid eq '-1' ) {
1683 print $OUT "\nDaughter DB session started...\n";
1684 }
1685 else {
1686 print $OUT "\nLoading DB routines from $header\n";
1687 print $OUT (
1688 "Editor support ",
1689 $slave_editor ? "enabled" : "available", ".\n"
1690 );
1691 print $OUT
1f874cb6 1692"\nEnter h or 'h h' for help, or '$doccmd perldebug' for more help.\n\n";
69893cff
RGS
1693 } ## end else [ if ($term_pid eq '-1')
1694 } ## end unless ($runnonstop)
1695} ## end else [ if ($notty)
1696
1697# XXX This looks like a bug to me.
1698# Why copy to @ARGS and then futz with @args?
d338d6fe 1699@ARGS = @ARGV;
6b24a4b7 1700# for (@args) {
69893cff
RGS
1701 # Make sure backslashes before single quotes are stripped out, and
1702 # keep args unless they are numeric (XXX why?)
e22ea7cc
RF
1703 # s/\'/\\\'/g; # removed while not justified understandably
1704 # s/(.*)/'$1'/ unless /^-?[\d.]+$/; # ditto
6b24a4b7 1705# }
d338d6fe 1706
e22ea7cc 1707# If there was an afterinit() sub defined, call it. It will get
69893cff 1708# executed in our scope, so it can fiddle with debugger globals.
e22ea7cc 1709if ( defined &afterinit ) { # May be defined in $rcfile
2b0b9dd1 1710 afterinit();
d338d6fe 1711}
e22ea7cc 1712
69893cff 1713# Inform us about "Stack dump during die enabled ..." in dieLevel().
6b24a4b7
SF
1714use vars qw($I_m_init);
1715
43aed9ee
IZ
1716$I_m_init = 1;
1717
d338d6fe
PP
1718############################################################ Subroutines
1719
69893cff
RGS
1720=head1 SUBROUTINES
1721
1722=head2 DB
1723
1724This gigantic subroutine is the heart of the debugger. Called before every
1725statement, its job is to determine if a breakpoint has been reached, and
1726stop if so; read commands from the user, parse them, and execute
b468dcb6 1727them, and then send execution off to the next statement.
69893cff
RGS
1728
1729Note that the order in which the commands are processed is very important;
1730some commands earlier in the loop will actually alter the C<$cmd> variable
be9a9b1d 1731to create other commands to be executed later. This is all highly I<optimized>
69893cff
RGS
1732but can be confusing. Check the comments for each C<$cmd ... && do {}> to
1733see what's happening in any given command.
1734
1735=cut
1736
6b24a4b7
SF
1737use vars qw(
1738 $action
1739 %alias
1740 $cmd
1741 $doret
1742 $fall_off_end
1743 $file
1744 $filename_ini
1745 $finished
1746 %had_breakpoints
1747 $incr
1748 $laststep
1749 $level
1750 $max
1751 @old_watch
1752 $package
1753 $rc
1754 $sh
1755 @stack
1756 $stack_depth
1757 @to_watch
1758 $try
2c247e84 1759 $end
6b24a4b7
SF
1760);
1761
6791e41b
SF
1762sub _DB__determine_if_we_should_break
1763{
1764 # if we have something here, see if we should break.
1765 # $stop is lexical and local to this block - $action on the other hand
1766 # is global.
1767 my $stop;
1768
1769 if ( $dbline{$line}
1770 && _is_breakpoint_enabled($filename, $line)
1771 && (( $stop, $action ) = split( /\0/, $dbline{$line} ) ) )
1772 {
1773
1774 # Stop if the stop criterion says to just stop.
1775 if ( $stop eq '1' ) {
1776 $signal |= 1;
1777 }
1778
1779 # It's a conditional stop; eval it in the user's context and
1780 # see if we should stop. If so, remove the one-time sigil.
1781 elsif ($stop) {
1782 $evalarg = "\$DB::signal |= 1 if do {$stop}";
1783 &eval;
1784 # If the breakpoint is temporary, then delete its enabled status.
1785 if ($dbline{$line} =~ s/;9($|\0)/$1/) {
1786 _cancel_breakpoint_temp_enabled_status($filename, $line);
1787 }
1788 }
1789 } ## end if ($dbline{$line} && ...
1790}
1791
8481f647
SF
1792sub _DB__is_finished {
1793 if ($finished and $level <= 1) {
1794 end_report();
1795 return 1;
1796 }
1797 else {
1798 return;
1799 }
1800}
1801
32bbadc6
SF
1802sub _DB__read_next_cmd
1803{
1804 my ($tid) = @_;
1805
1806 # We have a terminal, or can get one ...
1807 if (!$term) {
1808 setterm();
1809 }
1810
1811 # ... and it belogs to this PID or we get one for this PID ...
1812 if ($term_pid != $$) {
1813 resetterm(1);
1814 }
1815
1816 # ... and we got a line of command input ...
1817 $cmd = DB::readline(
1818 "$pidprompt $tid DB"
1819 . ( '<' x $level )
1820 . ( $#hist + 1 )
1821 . ( '>' x $level ) . " "
1822 );
1823
1824 return defined($cmd);
1825}
1826
7013f40c
SF
1827sub _DB__trim_command_and_return_first_component {
1828 $cmd =~ s/\A\s+//s; # trim annoying leading whitespace
1829 $cmd =~ s/\s+\z//s; # trim annoying trailing whitespace
1830
1831 $cmd =~ m{\A(\S*)};
1832 return $1;
1833}
1834
2b0b9dd1
SF
1835sub DB {
1836
1837 # lock the debugger and get the thread id for the prompt
1838 lock($DBGR);
1839 my $tid;
1840 my $position;
1841 my ($prefix, $after, $infix);
1842 my $pat;
22fc883d 1843 my $explicit_stop;
2b0b9dd1
SF
1844
1845 if ($ENV{PERL5DB_THREADED}) {
1846 $tid = eval { "[".threads->tid."]" };
1847 }
1848
22fc883d
SF
1849 my $obj = DB::Obj->new(
1850 {
1851 position => \$position,
1852 prefix => \$prefix,
1853 after => \$after,
1854 explicit_stop => \$explicit_stop,
1855 infix => \$infix,
1856 },
1857 );
1858
1859 $obj->_DB_on_init__initialize_globals(@_);
2b0b9dd1 1860
69893cff
RGS
1861 # Preserve current values of $@, $!, $^E, $,, $/, $\, $^W.
1862 # The code being debugged may have altered them.
d338d6fe 1863 &save;
69893cff
RGS
1864
1865 # Since DB::DB gets called after every line, we can use caller() to
1866 # figure out where we last were executing. Sneaky, eh? This works because
e22ea7cc 1867 # caller is returning all the extra information when called from the
69893cff 1868 # debugger.
e22ea7cc 1869 local ( $package, $filename, $line ) = caller;
6b24a4b7 1870 $filename_ini = $filename;
69893cff
RGS
1871
1872 # set up the context for DB::eval, so it can properly execute
1873 # code on behalf of the user. We add the package in so that the
1874 # code is eval'ed in the proper package (not in the debugger!).
6b24a4b7 1875 local $usercontext = _calc_usercontext($package);
69893cff
RGS
1876
1877 # Create an alias to the active file magical array to simplify
1878 # the code here.
e22ea7cc 1879 local (*dbline) = $main::{ '_<' . $filename };
aa057b67 1880
69893cff 1881 # Last line in the program.
55783941 1882 $max = $#dbline;
69893cff 1883
22fc883d 1884 _DB__determine_if_we_should_break(@_);
69893cff
RGS
1885
1886 # Preserve the current stop-or-not, and see if any of the W
1887 # (watch expressions) has changed.
36477c24 1888 my $was_signal = $signal;
69893cff
RGS
1889
1890 # If we have any watch expressions ...
22fc883d 1891 $obj->_DB__handle_watch_expressions(@_);
69893cff
RGS
1892
1893=head2 C<watchfunction()>
1894
1895C<watchfunction()> is a function that can be defined by the user; it is a
b570d64b 1896function which will be run on each entry to C<DB::DB>; it gets the
69893cff
RGS
1897current package, filename, and line as its parameters.
1898
b570d64b 1899The watchfunction can do anything it likes; it is executing in the
69893cff
RGS
1900debugger's context, so it has access to all of the debugger's internal
1901data structures and functions.
1902
1903C<watchfunction()> can control the debugger's actions. Any of the following
1904will cause the debugger to return control to the user's program after
1905C<watchfunction()> executes:
1906
b570d64b 1907=over 4
69893cff 1908
be9a9b1d
AT
1909=item *
1910
1911Returning a false value from the C<watchfunction()> itself.
1912
1913=item *
1914
1915Altering C<$single> to a false value.
1916
1917=item *
69893cff 1918
be9a9b1d 1919Altering C<$signal> to a false value.
69893cff 1920
be9a9b1d 1921=item *
69893cff 1922
be9a9b1d 1923Turning off the C<4> bit in C<$trace> (this also disables the
69893cff
RGS
1924check for C<watchfunction()>. This can be done with
1925
1926 $trace &= ~4;
1927
1928=back
1929
1930=cut
1931
e22ea7cc 1932 # If there's a user-defined DB::watchfunction, call it with the
69893cff
RGS
1933 # current package, filename, and line. The function executes in
1934 # the DB:: package.
e22ea7cc
RF
1935 if ( $trace & 4 ) { # User-installed watch
1936 return
1937 if watchfunction( $package, $filename, $line )
1938 and not $single
1939 and not $was_signal
1940 and not( $trace & ~4 );
69893cff
RGS
1941 } ## end if ($trace & 4)
1942
e22ea7cc 1943 # Pick up any alteration to $signal in the watchfunction, and
69893cff 1944 # turn off the signal now.
6027b9a3 1945 $was_signal = $signal;
69893cff
RGS
1946 $signal = 0;
1947
1948=head2 GETTING READY TO EXECUTE COMMANDS
1949
1950The debugger decides to take control if single-step mode is on, the
1951C<t> command was entered, or the user generated a signal. If the program
1952has fallen off the end, we set things up so that entering further commands
1953won't cause trouble, and we say that the program is over.
1954
1955=cut
1956
8dc67a69
SF
1957 # Make sure that we always print if asked for explicitly regardless
1958 # of $trace_to_depth .
22fc883d 1959 $explicit_stop = ($single || $was_signal);
8dc67a69 1960
69893cff
RGS
1961 # Check to see if we should grab control ($single true,
1962 # trace set appropriately, or we got a signal).
8dc67a69 1963 if ( $explicit_stop || ( $trace & 1 ) ) {
22fc883d 1964 $obj->_DB__grab_control(@_);
69893cff
RGS
1965 } ## end if ($single || ($trace...
1966
1967=pod
1968
1969If there's an action to be executed for the line we stopped at, execute it.
b570d64b 1970If there are any preprompt actions, execute those as well.
e219e2fb
RF
1971
1972=cut
1973
69893cff 1974 # If there's an action, do it now.
05da04df
SF
1975 if ($action) {
1976 $evalarg = $action;
1977 DB::eval();
1978 }
e219e2fb 1979
69893cff
RGS
1980 # Are we nested another level (e.g., did we evaluate a function
1981 # that had a breakpoint in it at the debugger prompt)?
e22ea7cc
RF
1982 if ( $single || $was_signal ) {
1983
69893cff 1984 # Yes, go down a level.
e22ea7cc 1985 local $level = $level + 1;
69893cff
RGS
1986
1987 # Do any pre-prompt actions.
e22ea7cc 1988 foreach $evalarg (@$pre) {
7c54f46a 1989 DB::eval();
e22ea7cc 1990 }
69893cff
RGS
1991
1992 # Complain about too much recursion if we passed the limit.
05da04df
SF
1993 if ($single & 4) {
1994 print $OUT $stack_depth . " levels deep in subroutine calls!\n";
1995 }
69893cff
RGS
1996
1997 # The line we're currently on. Set $incr to -1 to stay here
1998 # until we get a command that tells us to advance.
e22ea7cc
RF
1999 $start = $line;
2000 $incr = -1; # for backward motion.
69893cff
RGS
2001
2002 # Tack preprompt debugger actions ahead of any actual input.
e22ea7cc 2003 @typeahead = ( @$pretype, @typeahead );
69893cff
RGS
2004
2005=head2 WHERE ARE WE?
2006
2007XXX Relocate this section?
2008
2009The debugger normally shows the line corresponding to the current line of
2010execution. Sometimes, though, we want to see the next line, or to move elsewhere
2011in the file. This is done via the C<$incr>, C<$start>, and C<$max> variables.
2012
be9a9b1d
AT
2013C<$incr> controls by how many lines the I<current> line should move forward
2014after a command is executed. If set to -1, this indicates that the I<current>
69893cff
RGS
2015line shouldn't change.
2016
be9a9b1d 2017C<$start> is the I<current> line. It is used for things like knowing where to
69893cff
RGS
2018move forwards or backwards from when doing an C<L> or C<-> command.
2019
2020C<$max> tells the debugger where the last line of the current file is. It's
2021used to terminate loops most often.
2022
2023=head2 THE COMMAND LOOP
2024
2025Most of C<DB::DB> is actually a command parsing and dispatch loop. It comes
2026in two parts:
2027
2028=over 4
2029
be9a9b1d
AT
2030=item *
2031
2032The outer part of the loop, starting at the C<CMD> label. This loop
69893cff
RGS
2033reads a command and then executes it.
2034
be9a9b1d
AT
2035=item *
2036
2037The inner part of the loop, starting at the C<PIPE> label. This part
69893cff
RGS
2038is wholly contained inside the C<CMD> block and only executes a command.
2039Used to handle commands running inside a pager.
2040
2041=back
2042
2043So why have two labels to restart the loop? Because sometimes, it's easier to
2044have a command I<generate> another command and then re-execute the loop to do
2045the new command. This is faster, but perhaps a bit more convoluted.
2046
2047=cut
2048
2049 # The big command dispatch loop. It keeps running until the
2050 # user yields up control again.
2051 #
2052 # If we have a terminal for input, and we get something back
2053 # from readline(), keep on processing.
6b24a4b7
SF
2054 my $piped;
2055 my $selected;
2056
e22ea7cc 2057 CMD:
32bbadc6 2058 while (_DB__read_next_cmd($tid))
69893cff 2059 {
e22ea7cc 2060
8380a245 2061 share($cmd);
69893cff
RGS
2062 # ... try to execute the input as debugger commands.
2063
2064 # Don't stop running.
2065 $single = 0;
2066
2067 # No signal is active.
2068 $signal = 0;
2069
2070 # Handle continued commands (ending with \):
3d7a2a93 2071 if ($cmd =~ s/\\\z/\n/) {
eeb7da96 2072 $cmd .= DB::readline(" cont: ");
e22ea7cc 2073 redo CMD;
3d7a2a93 2074 }
69893cff
RGS
2075
2076=head4 The null command
2077
be9a9b1d 2078A newline entered by itself means I<re-execute the last command>. We grab the
69893cff
RGS
2079command out of C<$laststep> (where it was recorded previously), and copy it
2080back into C<$cmd> to be executed below. If there wasn't any previous command,
2081we'll do nothing below (no command will match). If there was, we also save it
2082in the command history and fall through to allow the command parsing to pick
2083it up.
2084
2085=cut
2086
2087 # Empty input means repeat the last command.
eeb7da96
SF
2088 if ($cmd eq '') {
2089 $cmd = $laststep;
2090 }
e22ea7cc 2091 chomp($cmd); # get rid of the annoying extra newline
eeb7da96
SF
2092 if (length($cmd) >= 2) {
2093 push( @hist, $cmd );
2094 }
e22ea7cc 2095 push( @truehist, $cmd );
2dbd01ad
SF
2096 share(@hist);
2097 share(@truehist);
e22ea7cc
RF
2098
2099 # This is a restart point for commands that didn't arrive
2100 # via direct user input. It allows us to 'redo PIPE' to
2101 # re-execute command processing without reading a new command.
69893cff 2102 PIPE: {
7013f40c 2103 my $i = _DB__trim_command_and_return_first_component();
69893cff
RGS
2104
2105=head3 COMMAND ALIASES
2106
2107The debugger can create aliases for commands (these are stored in the
2108C<%alias> hash). Before a command is executed, the command loop looks it up
2109in the alias hash and substitutes the contents of the alias for the command,
2110completely replacing it.
2111
2112=cut
2113
2114 # See if there's an alias for the command, and set it up if so.
e22ea7cc
RF
2115 if ( $alias{$i} ) {
2116
69893cff
RGS
2117 # Squelch signal handling; we want to keep control here
2118 # if something goes loco during the alias eval.
2119 local $SIG{__DIE__};
2120 local $SIG{__WARN__};
2121
2122 # This is a command, so we eval it in the DEBUGGER's
2123 # scope! Otherwise, we can't see the special debugger
2124 # variables, or get to the debugger's subs. (Well, we
2125 # _could_, but why make it even more complicated?)
2126 eval "\$cmd =~ $alias{$i}";
2127 if ($@) {
2128 local $\ = '';
1f874cb6 2129 print $OUT "Couldn't evaluate '$i' alias: $@";
69893cff
RGS
2130 next CMD;
2131 }
2132 } ## end if ($alias{$i})
2133
2134=head3 MAIN-LINE COMMANDS
2135
2136All of these commands work up to and after the program being debugged has
b570d64b 2137terminated.
69893cff
RGS
2138
2139=head4 C<q> - quit
2140
b570d64b 2141Quit the debugger. This entails setting the C<$fall_off_end> flag, so we don't
69893cff
RGS
2142try to execute further, cleaning any restart-related stuff out of the
2143environment, and executing with the last value of C<$?>.
2144
2145=cut
2146
3d7a2a93 2147 if ($cmd eq 'q') {
69893cff
RGS
2148 $fall_off_end = 1;
2149 clean_ENV();
2150 exit $?;
3d7a2a93 2151 }
69893cff 2152
611272bb 2153=head4 C<t> - trace [n]
69893cff
RGS
2154
2155Turn tracing on or off. Inverts the appropriate bit in C<$trace> (q.v.).
611272bb 2156If level is specified, set C<$trace_to_depth>.
69893cff
RGS
2157
2158=cut
2159
3d7a2a93 2160 if (my ($levels) = $cmd =~ /\At(?:\s+(\d+))?\z/) {
e22ea7cc
RF
2161 $trace ^= 1;
2162 local $\ = '';
611272bb 2163 $trace_to_depth = $levels ? $stack_depth + $levels : 1E9;
e22ea7cc 2164 print $OUT "Trace = "
611272bb
PS
2165 . ( ( $trace & 1 )
2166 ? ( $levels ? "on (to level $trace_to_depth)" : "on" )
2167 : "off" ) . "\n";
e22ea7cc 2168 next CMD;
3d7a2a93 2169 }
69893cff
RGS
2170
2171=head4 C<S> - list subroutines matching/not matching a pattern
2172
2173Walks through C<%sub>, checking to see whether or not to print the name.
2174
2175=cut
2176
826b9a2e
SF
2177 if (my ($print_all_subs, $should_reverse, $Spatt)
2178 = $cmd =~ /\AS(\s+(!)?(.+))?\z/) {
2179 # $Spatt is the pattern (if any) to use.
2180 # Reverse scan?
2181 my $Srev = defined $should_reverse;
2182 # No args - print all subs.
2183 my $Snocheck = !defined $print_all_subs;
69893cff
RGS
2184
2185 # Need to make these sane here.
e22ea7cc
RF
2186 local $\ = '';
2187 local $, = '';
69893cff
RGS
2188
2189 # Search through the debugger's magical hash of subs.
2190 # If $nocheck is true, just print the sub name.
2191 # Otherwise, check it against the pattern. We then use
2192 # the XOR trick to reverse the condition as required.
e22ea7cc
RF
2193 foreach $subname ( sort( keys %sub ) ) {
2194 if ( $Snocheck or $Srev ^ ( $subname =~ /$Spatt/ ) ) {
2195 print $OUT $subname, "\n";
2196 }
2197 }
2198 next CMD;
826b9a2e 2199 }
69893cff
RGS
2200
2201=head4 C<X> - list variables in current package
2202
b570d64b 2203Since the C<V> command actually processes this, just change this to the
69893cff
RGS
2204appropriate C<V> command and fall through.
2205
2206=cut
2207
e22ea7cc 2208 $cmd =~ s/^X\b/V $package/;
69893cff
RGS
2209
2210=head4 C<V> - list variables
2211
b570d64b 2212Uses C<dumpvar.pl> to dump out the current values for selected variables.
69893cff
RGS
2213
2214=cut
2215
2216 # Bare V commands get the currently-being-debugged package
2217 # added.
826b9a2e 2218 if ($cmd eq "V") {
e22ea7cc 2219 $cmd = "V $package";
826b9a2e 2220 }
69893cff
RGS
2221
2222 # V - show variables in package.
826b9a2e
SF
2223 if (my ($new_packname, $new_vars_str) =
2224 $cmd =~ /\AV\b\s*(\S+)\s*(.*)/) {
e22ea7cc 2225
69893cff
RGS
2226 # Save the currently selected filehandle and
2227 # force output to debugger's filehandle (dumpvar
2228 # just does "print" for output).
6b24a4b7 2229 my $savout = select($OUT);
69893cff
RGS
2230
2231 # Grab package name and variables to dump.
826b9a2e
SF
2232 $packname = $new_packname;
2233 my @vars = split( ' ', $new_vars_str );
69893cff
RGS
2234
2235 # If main::dumpvar isn't here, get it.
e81465be 2236 do 'dumpvar.pl' || die $@ unless defined &main::dumpvar;
e22ea7cc
RF
2237 if ( defined &main::dumpvar ) {
2238
69893cff
RGS
2239 # We got it. Turn off subroutine entry/exit messages
2240 # for the moment, along with return values.
e22ea7cc
RF
2241 local $frame = 0;
2242 local $doret = -2;
69893cff
RGS
2243
2244 # must detect sigpipe failures - not catching
2245 # then will cause the debugger to die.
2246 eval {
2247 &main::dumpvar(
2248 $packname,
2249 defined $option{dumpDepth}
e22ea7cc
RF
2250 ? $option{dumpDepth}
2251 : -1, # assume -1 unless specified
69893cff 2252 @vars
e22ea7cc
RF
2253 );
2254 };
2255
2256 # The die doesn't need to include the $@, because
2257 # it will automatically get propagated for us.
2258 if ($@) {
2259 die unless $@ =~ /dumpvar print failed/;
2260 }
2261 } ## end if (defined &main::dumpvar)
2262 else {
2263
2264 # Couldn't load dumpvar.
2265 print $OUT "dumpvar.pl not available.\n";
2266 }
69893cff 2267
69893cff 2268 # Restore the output filehandle, and go round again.
e22ea7cc
RF
2269 select($savout);
2270 next CMD;
826b9a2e 2271 }
69893cff
RGS
2272
2273=head4 C<x> - evaluate and print an expression
2274
2275Hands the expression off to C<DB::eval>, setting it up to print the value
2276via C<dumpvar.pl> instead of just printing it directly.
2277
2278=cut
2279
826b9a2e 2280 if ($cmd =~ s#\Ax\b# #) { # Remainder gets done by DB::eval()
e22ea7cc 2281 $onetimeDump = 'dump'; # main::dumpvar shows the output
69893cff
RGS
2282
2283 # handle special "x 3 blah" syntax XXX propagate
2284 # doc back to special variables.
826b9a2e 2285 if ( $cmd =~ s#\A\s*(\d+)(?=\s)# #) {
e22ea7cc
RF
2286 $onetimedumpDepth = $1;
2287 }
826b9a2e 2288 }
69893cff
RGS
2289
2290=head4 C<m> - print methods
2291
2292Just uses C<DB::methods> to determine what methods are available.
2293
2294=cut
2295
826b9a2e 2296 if ($cmd =~ s#\Am\s+([\w:]+)\s*\z# #) {
e22ea7cc
RF
2297 methods($1);
2298 next CMD;
826b9a2e 2299 }
69893cff
RGS
2300
2301 # m expr - set up DB::eval to do the work
826b9a2e 2302 if ($cmd =~ s#\Am\b# #) { # Rest gets done by DB::eval()
e22ea7cc 2303 $onetimeDump = 'methods'; # method output gets used there
826b9a2e 2304 }
69893cff
RGS
2305
2306=head4 C<f> - switch files
2307
2308=cut
2309
826b9a2e 2310 if (($file) = $cmd =~ /\Af\b\s*(.*)/) {
e22ea7cc 2311 $file =~ s/\s+$//;
69893cff
RGS
2312
2313 # help for no arguments (old-style was return from sub).
e22ea7cc
RF
2314 if ( !$file ) {
2315 print $OUT
2316 "The old f command is now the r command.\n"; # hint
2317 print $OUT "The new f command switches filenames.\n";
2318 next CMD;
2319 } ## end if (!$file)
69893cff
RGS
2320
2321 # if not in magic file list, try a close match.
e22ea7cc
RF
2322 if ( !defined $main::{ '_<' . $file } ) {
2323 if ( ($try) = grep( m#^_<.*$file#, keys %main:: ) ) {
2324 {
2325 $try = substr( $try, 2 );
1f874cb6 2326 print $OUT "Choosing $try matching '$file':\n";
e22ea7cc
RF
2327 $file = $try;
2328 }
2329 } ## end if (($try) = grep(m#^_<.*$file#...
2330 } ## end if (!defined $main::{ ...
69893cff
RGS
2331
2332 # If not successfully switched now, we failed.
e22ea7cc 2333 if ( !defined $main::{ '_<' . $file } ) {
1f874cb6 2334 print $OUT "No file matching '$file' is loaded.\n";
e22ea7cc
RF
2335 next CMD;
2336 }
69893cff 2337
e22ea7cc
RF
2338 # We switched, so switch the debugger internals around.
2339 elsif ( $file ne $filename ) {
2340 *dbline = $main::{ '_<' . $file };
2341 $max = $#dbline;
2342 $filename = $file;
2343 $start = 1;
2344 $cmd = "l";
2345 } ## end elsif ($file ne $filename)
2346
2347 # We didn't switch; say we didn't.
2348 else {
2349 print $OUT "Already in $file.\n";
2350 next CMD;
2351 }
826b9a2e 2352 }
69893cff
RGS
2353
2354=head4 C<.> - return to last-executed line.
2355
2356We set C<$incr> to -1 to indicate that the debugger shouldn't move ahead,
2357and then we look up the line in the magical C<%dbline> hash.
2358
2359=cut
2360
2361 # . command.
826b9a2e 2362 if ($cmd eq '.') {
e22ea7cc 2363 $incr = -1; # stay at current line
69893cff
RGS
2364
2365 # Reset everything to the old location.
e22ea7cc
RF
2366 $start = $line;
2367 $filename = $filename_ini;
2368 *dbline = $main::{ '_<' . $filename };
2369 $max = $#dbline;
69893cff
RGS
2370
2371 # Now where are we?
e22ea7cc
RF
2372 print_lineinfo($position);
2373 next CMD;
826b9a2e 2374 }
69893cff
RGS
2375
2376=head4 C<-> - back one window
2377
2378We change C<$start> to be one window back; if we go back past the first line,
2379we set it to be the first line. We ser C<$incr> to put us back at the
2380currently-executing line, and then put a C<l $start +> (list one window from
2381C<$start>) in C<$cmd> to be executed later.
2382
2383=cut
2384
2385 # - - back a window.
826b9a2e 2386 if ($cmd eq '-') {
e22ea7cc 2387
69893cff 2388 # back up by a window; go to 1 if back too far.
e22ea7cc
RF
2389 $start -= $incr + $window + 1;
2390 $start = 1 if $start <= 0;
2391 $incr = $window - 1;
69893cff
RGS
2392
2393 # Generate and execute a "l +" command (handled below).
e22ea7cc 2394 $cmd = 'l ' . ($start) . '+';
826b9a2e 2395 }
69893cff 2396
8481f647 2397=head3 PRE-580 COMMANDS VS. NEW COMMANDS: C<a, A, b, B, h, l, L, M, o, O, P, v, w, W, E<lt>, E<lt>E<lt>, E<0x7B>, E<0x7B>E<0x7B>>
69893cff
RGS
2398
2399In Perl 5.8.0, a realignment of the commands was done to fix up a number of
2400problems, most notably that the default case of several commands destroying
2401the user's work in setting watchpoints, actions, etc. We wanted, however, to
2402retain the old commands for those who were used to using them or who preferred
2403them. At this point, we check for the new commands and call C<cmd_wrapper> to
2404deal with them instead of processing them in-line.
2405
2406=cut
2407
2408 # All of these commands were remapped in perl 5.8.0;
e22ea7cc 2409 # we send them off to the secondary dispatcher (see below).
826b9a2e
SF
2410 if (my ($cmd_letter, $my_arg) = $cmd =~ /\A([aAbBeEhilLMoOPvwW]\b|[<>\{]{1,2})\s*(.*)/so) {
2411 &cmd_wrapper( $cmd_letter, $my_arg, $line );
e22ea7cc 2412 next CMD;
826b9a2e 2413 }
69893cff
RGS
2414
2415=head4 C<y> - List lexicals in higher scope
2416
826b9a2e 2417Uses C<PadWalker> to find the lexicals supplied as arguments in a scope
69893cff
RGS
2418above the current one and then displays then using C<dumpvar.pl>.
2419
2420=cut
2421
826b9a2e
SF
2422 if (my ($match_level, $match_vars)
2423 = $cmd =~ /^y(?:\s+(\d*)\s*(.*))?$/) {
69893cff
RGS
2424
2425 # See if we've got the necessary support.
2426 eval { require PadWalker; PadWalker->VERSION(0.08) }
2427 or &warn(
2428 $@ =~ /locate/
2429 ? "PadWalker module not found - please install\n"
2430 : $@
2431 )
2432 and next CMD;
2433
2434 # Load up dumpvar if we don't have it. If we can, that is.
e81465be 2435 do 'dumpvar.pl' || die $@ unless defined &main::dumpvar;
69893cff
RGS
2436 defined &main::dumpvar
2437 or print $OUT "dumpvar.pl not available.\n"
2438 and next CMD;
2439
2440 # Got all the modules we need. Find them and print them.
826b9a2e 2441 my @vars = split( ' ', $match_vars || '' );
69893cff
RGS
2442
2443 # Find the pad.
826b9a2e 2444 my $h = eval { PadWalker::peek_my( ( $match_level || 0 ) + 1 ) };
69893cff
RGS
2445
2446 # Oops. Can't find it.
2447 $@ and $@ =~ s/ at .*//, &warn($@), next CMD;
2448
2449 # Show the desired vars with dumplex().
2450 my $savout = select($OUT);
2451
2452 # Have dumplex dump the lexicals.
e22ea7cc 2453 dumpvar::dumplex( $_, $h->{$_},
69893cff 2454 defined $option{dumpDepth} ? $option{dumpDepth} : -1,
e22ea7cc
RF
2455 @vars )
2456 for sort keys %$h;
69893cff
RGS
2457 select($savout);
2458 next CMD;
826b9a2e 2459 }
69893cff
RGS
2460
2461=head3 COMMANDS NOT WORKING AFTER PROGRAM ENDS
2462
2463All of the commands below this point don't work after the program being
2464debugged has ended. All of them check to see if the program has ended; this
2465allows the commands to be relocated without worrying about a 'line of
2466demarcation' above which commands can be entered anytime, and below which
2467they can't.
2468
2469=head4 C<n> - single step, but don't trace down into subs
2470
2471Done by setting C<$single> to 2, which forces subs to execute straight through
be9a9b1d 2472when entered (see C<DB::sub>). We also save the C<n> command in C<$laststep>,
826b9a2e 2473so a null command knows what to re-execute.
69893cff
RGS
2474
2475=cut
2476
e22ea7cc 2477 # n - next
826b9a2e 2478 if ($cmd eq 'n') {
8481f647 2479 next CMD if _DB__is_finished();
e22ea7cc 2480
69893cff
RGS
2481 # Single step, but don't enter subs.
2482 $single = 2;
e22ea7cc 2483
69893cff 2484 # Save for empty command (repeat last).
e22ea7cc
RF
2485 $laststep = $cmd;
2486 last CMD;
826b9a2e 2487 }
69893cff
RGS
2488
2489=head4 C<s> - single-step, entering subs
2490
826b9a2e 2491Sets C<$single> to 1, which causes C<DB::sub> to continue tracing inside
69893cff
RGS
2492subs. Also saves C<s> as C<$lastcmd>.
2493
2494=cut
2495
2496 # s - single step.
826b9a2e 2497 if ($cmd eq 's') {
e22ea7cc 2498
69893cff
RGS
2499 # Get out and restart the command loop if program
2500 # has finished.
8481f647 2501 next CMD if _DB__is_finished();
e22ea7cc 2502
69893cff 2503 # Single step should enter subs.
e22ea7cc
RF
2504 $single = 1;
2505
69893cff 2506 # Save for empty command (repeat last).
e22ea7cc
RF
2507 $laststep = $cmd;
2508 last CMD;
826b9a2e 2509 }
69893cff
RGS
2510
2511=head4 C<c> - run continuously, setting an optional breakpoint
2512
2513Most of the code for this command is taken up with locating the optional
2514breakpoint, which is either a subroutine name or a line number. We set
2515the appropriate one-time-break in C<@dbline> and then turn off single-stepping
2516in this and all call levels above this one.
2517
2518=cut
2519
2520 # c - start continuous execution.
ef18ae63 2521 if (($i) = $cmd =~ m#\Ac\b\s*([\w:]*)\s*\z#) {
e22ea7cc 2522
69893cff
RGS
2523 # Hey, show's over. The debugged program finished
2524 # executing already.
8481f647 2525 next CMD if _DB__is_finished();
69893cff
RGS
2526
2527 # Capture the place to put a one-time break.
ef18ae63 2528 $subname = $i;
69893cff 2529
e22ea7cc
RF
2530 # Probably not needed, since we finish an interactive
2531 # sub-session anyway...
2532 # local $filename = $filename;
2533 # local *dbline = *dbline; # XXX Would this work?!
69893cff
RGS
2534 #
2535 # The above question wonders if localizing the alias
2536 # to the magic array works or not. Since it's commented
2537 # out, we'll just leave that to speculation for now.
2538
2539 # If the "subname" isn't all digits, we'll assume it
2540 # is a subroutine name, and try to find it.
e22ea7cc
RF
2541 if ( $subname =~ /\D/ ) { # subroutine name
2542 # Qualify it to the current package unless it's
2543 # already qualified.
69893cff
RGS
2544 $subname = $package . "::" . $subname
2545 unless $subname =~ /::/;
e22ea7cc 2546
69893cff
RGS
2547 # find_sub will return "file:line_number" corresponding
2548 # to where the subroutine is defined; we call find_sub,
e22ea7cc 2549 # break up the return value, and assign it in one
69893cff 2550 # operation.
e22ea7cc 2551 ( $file, $i ) = ( find_sub($subname) =~ /^(.*):(.*)$/ );
69893cff
RGS
2552
2553 # Force the line number to be numeric.
e22ea7cc 2554 $i += 0;
69893cff
RGS
2555
2556 # If we got a line number, we found the sub.
e22ea7cc
RF
2557 if ($i) {
2558
69893cff
RGS
2559 # Switch all the debugger's internals around so
2560 # we're actually working with that file.
e22ea7cc
RF
2561 $filename = $file;
2562 *dbline = $main::{ '_<' . $filename };
2563
69893cff 2564 # Mark that there's a breakpoint in this file.
e22ea7cc
RF
2565 $had_breakpoints{$filename} |= 1;
2566
69893cff
RGS
2567 # Scan forward to the first executable line
2568 # after the 'sub whatever' line.
e22ea7cc
RF
2569 $max = $#dbline;
2570 ++$i while $dbline[$i] == 0 && $i < $max;
2571 } ## end if ($i)
69893cff
RGS
2572
2573 # We didn't find a sub by that name.
e22ea7cc
RF
2574 else {
2575 print $OUT "Subroutine $subname not found.\n";
2576 next CMD;
2577 }
2578 } ## end if ($subname =~ /\D/)
69893cff
RGS
2579
2580 # At this point, either the subname was all digits (an
2581 # absolute line-break request) or we've scanned through
2582 # the code following the definition of the sub, looking
2583 # for an executable, which we may or may not have found.
2584 #
2585 # If $i (which we set $subname from) is non-zero, we
e22ea7cc
RF
2586 # got a request to break at some line somewhere. On
2587 # one hand, if there wasn't any real subroutine name
2588 # involved, this will be a request to break in the current
2589 # file at the specified line, so we have to check to make
69893cff
RGS
2590 # sure that the line specified really is breakable.
2591 #
2592 # On the other hand, if there was a subname supplied, the
3c4b39be 2593 # preceding block has moved us to the proper file and
69893cff
RGS
2594 # location within that file, and then scanned forward
2595 # looking for the next executable line. We have to make
2596 # sure that one was found.
2597 #
2598 # On the gripping hand, we can't do anything unless the
2599 # current value of $i points to a valid breakable line.
2600 # Check that.
e22ea7cc
RF
2601 if ($i) {
2602
69893cff 2603 # Breakable?
e22ea7cc
RF
2604 if ( $dbline[$i] == 0 ) {
2605 print $OUT "Line $i not breakable.\n";
2606 next CMD;
2607 }
2608
69893cff 2609 # Yes. Set up the one-time-break sigil.
e22ea7cc 2610 $dbline{$i} =~ s/($|\0)/;9$1/; # add one-time-only b.p.
5d5d9ea3 2611 _enable_breakpoint_temp_enabled_status($filename, $i);
e22ea7cc 2612 } ## end if ($i)
69893cff
RGS
2613
2614 # Turn off stack tracing from here up.
2c247e84
SF
2615 for my $i (0 .. $stack_depth) {
2616 $stack[ $i ] &= ~1;
e22ea7cc
RF
2617 }
2618 last CMD;
ef18ae63 2619 }
69893cff
RGS
2620
2621=head4 C<r> - return from a subroutine
2622
2623For C<r> to work properly, the debugger has to stop execution again
2624immediately after the return is executed. This is done by forcing
2625single-stepping to be on in the call level above the current one. If
2626we are printing return values when a C<r> is executed, set C<$doret>
2627appropriately, and force us out of the command loop.
2628
2629=cut
2630
2631 # r - return from the current subroutine.
ef18ae63 2632 if ($cmd eq 'r') {
e22ea7cc 2633
98dc9551 2634 # Can't do anything if the program's over.
8481f647 2635 next CMD if _DB__is_finished();
e22ea7cc 2636
69893cff 2637 # Turn on stack trace.
e22ea7cc
RF
2638 $stack[$stack_depth] |= 1;
2639
69893cff 2640 # Print return value unless the stack is empty.
e22ea7cc
RF
2641 $doret = $option{PrintRet} ? $stack_depth - 1 : -2;
2642 last CMD;
ef18ae63 2643 }
69893cff 2644
69893cff
RGS
2645=head4 C<T> - stack trace
2646
2647Just calls C<DB::print_trace>.
2648
2649=cut
2650
ef18ae63 2651 if ($cmd eq 'T') {
e22ea7cc
RF
2652 print_trace( $OUT, 1 ); # skip DB
2653 next CMD;
ef18ae63 2654 }
69893cff
RGS
2655
2656=head4 C<w> - List window around current line.
2657
2658Just calls C<DB::cmd_w>.
2659
2660=cut
2661
ef18ae63
SF
2662 if (my ($arg) = $cmd =~ /\Aw\b\s*(.*)/s) {
2663 &cmd_w( 'w', $arg );
2664 next CMD;
2665 }
69893cff
RGS
2666
2667=head4 C<W> - watch-expression processing.
2668
b570d64b 2669Just calls C<DB::cmd_W>.
69893cff
RGS
2670
2671=cut
2672
ef18ae63
SF
2673 if (my ($arg) = $cmd =~ /\AW\b\s*(.*)/s) {
2674 &cmd_W( 'W', $arg );
2675 next CMD;
2676 }
69893cff
RGS
2677
2678=head4 C</> - search forward for a string in the source
2679
ef18ae63 2680We take the argument and treat it as a pattern. If it turns out to be a
69893cff 2681bad one, we return the error we got from trying to C<eval> it and exit.
ef18ae63 2682If not, we create some code to do the search and C<eval> it so it can't
69893cff
RGS
2683mess us up.
2684
2685=cut
2686
ef18ae63
SF
2687 # The pattern as a string.
2688 use vars qw($inpat);
69893cff 2689
ef18ae63 2690 if (($inpat) = $cmd =~ m#\A/(.*)\z#) {
69893cff
RGS
2691
2692 # Remove the final slash.
e22ea7cc 2693 $inpat =~ s:([^\\])/$:$1:;
69893cff
RGS
2694
2695 # If the pattern isn't null ...
e22ea7cc 2696 if ( $inpat ne "" ) {
69893cff
RGS
2697
2698 # Turn of warn and die procesing for a bit.
e22ea7cc
RF
2699 local $SIG{__DIE__};
2700 local $SIG{__WARN__};
69893cff
RGS
2701
2702 # Create the pattern.
22fc883d 2703 eval 'no strict q/vars/; $inpat =~ m' . "\a$inpat\a";
e22ea7cc
RF
2704 if ( $@ ne "" ) {
2705
69893cff 2706 # Oops. Bad pattern. No biscuit.
e22ea7cc 2707 # Print the eval error and go back for more
69893cff 2708 # commands.
e22ea7cc
RF
2709 print $OUT "$@";
2710 next CMD;
2711 }
2712 $pat = $inpat;
2713 } ## end if ($inpat ne "")
69893cff
RGS
2714
2715 # Set up to stop on wrap-around.
e22ea7cc 2716 $end = $start;
69893cff
RGS
2717
2718 # Don't move off the current line.
e22ea7cc 2719 $incr = -1;
69893cff
RGS
2720
2721 # Done in eval so nothing breaks if the pattern
2722 # does something weird.
e22ea7cc 2723 eval '
22fc883d 2724 no strict q/vars/;
e22ea7cc 2725 for (;;) {
69893cff 2726 # Move ahead one line.
e22ea7cc 2727 ++$start;
69893cff
RGS
2728
2729 # Wrap if we pass the last line.
e22ea7cc 2730 $start = 1 if ($start > $max);
69893cff
RGS
2731
2732 # Stop if we have gotten back to this line again,
e22ea7cc 2733 last if ($start == $end);
69893cff
RGS
2734
2735 # A hit! (Note, though, that we are doing
2736 # case-insensitive matching. Maybe a qr//
2737 # expression would be better, so the user could
2738 # do case-sensitive matching if desired.
e22ea7cc
RF
2739 if ($dbline[$start] =~ m' . "\a$pat\a" . 'i) {
2740 if ($slave_editor) {
69893cff 2741 # Handle proper escaping in the slave.
e22ea7cc 2742 print $OUT "\032\032$filename:$start:0\n";
b570d64b 2743 }
e22ea7cc 2744 else {
69893cff 2745 # Just print the line normally.
e22ea7cc
RF
2746 print $OUT "$start:\t",$dbline[$start],"\n";
2747 }
69893cff 2748 # And quit since we found something.
e22ea7cc
RF
2749 last;
2750 }
2751 } ';
2752
69893cff 2753 # If we wrapped, there never was a match.
e22ea7cc
RF
2754 print $OUT "/$pat/: not found\n" if ( $start == $end );
2755 next CMD;
ef18ae63 2756 }
69893cff
RGS
2757
2758=head4 C<?> - search backward for a string in the source
2759
2760Same as for C</>, except the loop runs backwards.
2761
2762=cut
2763
2764 # ? - backward pattern search.
ef18ae63 2765 if (my ($inpat) = $cmd =~ m#\A\?(.*)\z#) {
69893cff
RGS
2766
2767 # Get the pattern, remove trailing question mark.
e22ea7cc 2768 $inpat =~ s:([^\\])\?$:$1:;
69893cff
RGS
2769
2770 # If we've got one ...
e22ea7cc 2771 if ( $inpat ne "" ) {
69893cff
RGS
2772
2773 # Turn off die & warn handlers.
e22ea7cc
RF
2774 local $SIG{__DIE__};
2775 local $SIG{__WARN__};
2776 eval '$inpat =~ m' . "\a$inpat\a";
2777
2778 if ( $@ ne "" ) {
2779
69893cff 2780 # Ouch. Not good. Print the error.
e22ea7cc
RF
2781 print $OUT $@;
2782 next CMD;
2783 }
2784 $pat = $inpat;
69893cff 2785 } ## end if ($inpat ne "")
e22ea7cc 2786
69893cff 2787 # Where we are now is where to stop after wraparound.
e22ea7cc 2788 $end = $start;
69893cff
RGS
2789
2790 # Don't move away from this line.
e22ea7cc 2791 $incr = -1;
69893cff
RGS
2792
2793 # Search inside the eval to prevent pattern badness
2794 # from killing us.
e22ea7cc 2795 eval '
22fc883d 2796 no strict q/vars/;
e22ea7cc 2797 for (;;) {
69893cff 2798 # Back up a line.
e22ea7cc 2799 --$start;
69893cff
RGS
2800
2801 # Wrap if we pass the first line.
e22ea7cc
RF
2802
2803 $start = $max if ($start <= 0);
69893cff
RGS
2804
2805 # Quit if we get back where we started,
e22ea7cc 2806 last if ($start == $end);
69893cff
RGS
2807
2808 # Match?
e22ea7cc
RF
2809 if ($dbline[$start] =~ m' . "\a$pat\a" . 'i) {
2810 if ($slave_editor) {
69893cff 2811 # Yep, follow slave editor requirements.
e22ea7cc 2812 print $OUT "\032\032$filename:$start:0\n";
b570d64b 2813 }
e22ea7cc 2814 else {
69893cff 2815 # Yep, just print normally.
e22ea7cc
RF
2816 print $OUT "$start:\t",$dbline[$start],"\n";
2817 }
69893cff
RGS
2818
2819 # Found, so done.
e22ea7cc
RF
2820 last;
2821 }
2822 } ';
2823
2824 # Say we failed if the loop never found anything,
2825 print $OUT "?$pat?: not found\n" if ( $start == $end );
2826 next CMD;
ef18ae63 2827 }
69893cff
RGS
2828
2829=head4 C<$rc> - Recall command
2830
2831Manages the commands in C<@hist> (which is created if C<Term::ReadLine> reports
2832that the terminal supports history). It find the the command required, puts it
2833into C<$cmd>, and redoes the loop to execute it.
2834
2835=cut
2836
e22ea7cc 2837 # $rc - recall command.
ef18ae63 2838 if (my ($minus, $arg) = $cmd =~ m#\A$rc+\s*(-)?(\d+)?\z#) {
69893cff
RGS
2839
2840 # No arguments, take one thing off history.
e22ea7cc 2841 pop(@hist) if length($cmd) > 1;
69893cff 2842
e22ea7cc 2843 # Relative (- found)?
69893cff 2844 # Y - index back from most recent (by 1 if bare minus)
e22ea7cc 2845 # N - go to that particular command slot or the last
69893cff 2846 # thing if nothing following.
ef18ae63 2847 $i = $minus ? ( $#hist - ( $arg || 1 ) ) : ( $arg || $#hist );
69893cff
RGS
2848
2849 # Pick out the command desired.
e22ea7cc 2850 $cmd = $hist[$i];
69893cff
RGS
2851
2852 # Print the command to be executed and restart the loop
2853 # with that command in the buffer.
e22ea7cc
RF
2854 print $OUT $cmd, "\n";
2855 redo CMD;
ef18ae63 2856 }
69893cff
RGS
2857
2858=head4 C<$sh$sh> - C<system()> command
2859
2860Calls the C<DB::system()> to handle the command. This keeps the C<STDIN> and
2861C<STDOUT> from getting messed up.
2862
2863=cut
2864
2865 # $sh$sh - run a shell command (if it's all ASCII).
2866 # Can't run shell commands with Unicode in the debugger, hmm.
ef18ae63 2867 if (my ($arg) = $cmd =~ m#\A$sh$sh\s*(.*)#ms) {
e22ea7cc 2868
69893cff 2869 # System it.
ef18ae63 2870 &system($arg);
e22ea7cc 2871 next CMD;
ef18ae63 2872 }
69893cff
RGS
2873
2874=head4 C<$rc I<pattern> $rc> - Search command history
2875
2876Another command to manipulate C<@hist>: this one searches it with a pattern.
be9a9b1d 2877If a command is found, it is placed in C<$cmd> and executed via C<redo>.
69893cff
RGS
2878
2879=cut
2880
e22ea7cc 2881 # $rc pattern $rc - find a command in the history.
ef18ae63 2882 if (my ($arg) = $cmd =~ /\A$rc([^$rc].*)\z/) {
e22ea7cc 2883
69893cff 2884 # Create the pattern to use.
ef18ae63 2885 $pat = "^$arg";
69893cff
RGS
2886
2887 # Toss off last entry if length is >1 (and it always is).
e22ea7cc 2888 pop(@hist) if length($cmd) > 1;
69893cff
RGS
2889
2890 # Look backward through the history.
72d7d80d 2891 for ( $i = $#hist ; $i ; --$i ) {
69893cff 2892 # Stop if we find it.
e22ea7cc
RF
2893 last if $hist[$i] =~ /$pat/;
2894 }
2895
2896 if ( !$i ) {
69893cff 2897
69893cff 2898 # Never found it.
e22ea7cc
RF
2899 print $OUT "No such command!\n\n";
2900 next CMD;
2901 }
69893cff
RGS
2902
2903 # Found it. Put it in the buffer, print it, and process it.
e22ea7cc
RF
2904 $cmd = $hist[$i];
2905 print $OUT $cmd, "\n";
2906 redo CMD;
ef18ae63 2907 }
69893cff 2908
ef18ae63 2909=head4 C<$sh> - Invoke a shell
69893cff
RGS
2910
2911Uses C<DB::system> to invoke a shell.
2912
2913=cut
2914
2915 # $sh - start a shell.
ef18ae63 2916 if ($cmd =~ /\A$sh\z/) {
e22ea7cc 2917
69893cff
RGS
2918 # Run the user's shell. If none defined, run Bourne.
2919 # We resume execution when the shell terminates.
e22ea7cc
RF
2920 &system( $ENV{SHELL} || "/bin/sh" );
2921 next CMD;
ef18ae63 2922 }
69893cff
RGS
2923
2924=head4 C<$sh I<command>> - Force execution of a command in a shell
2925
2926Like the above, but the command is passed to the shell. Again, we use
2927C<DB::system> to avoid problems with C<STDIN> and C<STDOUT>.
2928
2929=cut
2930
2931 # $sh command - start a shell and run a command in it.
ef18ae63 2932 if (my ($arg) = $cmd =~ m#\A$sh\s*(.*)#ms) {
e22ea7cc
RF
2933
2934 # XXX: using csh or tcsh destroys sigint retvals!
2935 #&system($1); # use this instead
69893cff
RGS
2936
2937 # use the user's shell, or Bourne if none defined.
ef18ae63 2938 &system( $ENV{SHELL} || "/bin/sh", "-c", $arg );
e22ea7cc 2939 next CMD;
ef18ae63 2940 }
69893cff
RGS
2941
2942=head4 C<H> - display commands in history
2943
2944Prints the contents of C<@hist> (if any).
2945
2946=cut
2947
ef18ae63 2948 if ($cmd =~ /\AH\b\s*\*/) {
7fddc82f
RF
2949 @hist = @truehist = ();
2950 print $OUT "History cleansed\n";
2951 next CMD;
ef18ae63 2952 }
e22ea7cc 2953
ef18ae63
SF
2954 if (my ($num)
2955 = $cmd =~ /\AH\b\s*(?:-(\d+))?/) {
e22ea7cc
RF
2956
2957 # Anything other than negative numbers is ignored by
69893cff 2958 # the (incorrect) pattern, so this test does nothing.
ef18ae63 2959 $end = $num ? ( $#hist - $num ) : 0;
69893cff
RGS
2960
2961 # Set to the minimum if less than zero.
e22ea7cc 2962 $hist = 0 if $hist < 0;
69893cff 2963
e22ea7cc 2964 # Start at the end of the array.
69893cff
RGS
2965 # Stay in while we're still above the ending value.
2966 # Tick back by one each time around the loop.
72d7d80d 2967 for ( $i = $#hist ; $i > $end ; $i-- ) {
69893cff
RGS
2968
2969 # Print the command unless it has no arguments.
e22ea7cc
RF
2970 print $OUT "$i: ", $hist[$i], "\n"
2971 unless $hist[$i] =~ /^.?$/;
2972 }
2973 next CMD;
ef18ae63 2974 }
69893cff
RGS
2975
2976=head4 C<man, doc, perldoc> - look up documentation
2977
2978Just calls C<runman()> to print the appropriate document.
2979
2980=cut
2981
e22ea7cc 2982 # man, perldoc, doc - show manual pages.
ef18ae63
SF
2983 if (my ($man_page)
2984 = $cmd =~ /\A(?:man|(?:perl)?doc)\b(?:\s+([^(]*))?\z/) {
2985 runman($man_page);
e22ea7cc 2986 next CMD;
ef18ae63 2987 }
69893cff
RGS
2988
2989=head4 C<p> - print
2990
2991Builds a C<print EXPR> expression in the C<$cmd>; this will get executed at
2992the bottom of the loop.
2993
2994=cut
2995
ef18ae63 2996 my $print_cmd = 'print {$DB::OUT} ';
69893cff 2997 # p - print (no args): print $_.
ef18ae63
SF
2998 if ($cmd eq 'p') {
2999 $cmd = $print_cmd . '$_';
3000 }
69893cff
RGS
3001
3002 # p - print the given expression.
ef18ae63 3003 $cmd =~ s/\Ap\b/$print_cmd /;
69893cff
RGS
3004
3005=head4 C<=> - define command alias
3006
3007Manipulates C<%alias> to add or list command aliases.
3008
3009=cut
3010
e22ea7cc 3011 # = - set up a command alias.
ef18ae63 3012 if ($cmd =~ s/\A=\s*//) {
e22ea7cc
RF
3013 my @keys;
3014 if ( length $cmd == 0 ) {
3015
69893cff 3016 # No args, get current aliases.
e22ea7cc
RF
3017 @keys = sort keys %alias;
3018 }
3019 elsif ( my ( $k, $v ) = ( $cmd =~ /^(\S+)\s+(\S.*)/ ) ) {
3020
69893cff
RGS
3021 # Creating a new alias. $k is alias name, $v is
3022 # alias value.
3023
e22ea7cc
RF
3024 # can't use $_ or kill //g state
3025 for my $x ( $k, $v ) {
3026
3027 # Escape "alarm" characters.
3028 $x =~ s/\a/\\a/g;
3029 }
69893cff
RGS
3030
3031 # Substitute key for value, using alarm chars
e22ea7cc 3032 # as separators (which is why we escaped them in
69893cff 3033 # the command).
e22ea7cc 3034 $alias{$k} = "s\a$k\a$v\a";
69893cff
RGS
3035
3036 # Turn off standard warn and die behavior.
e22ea7cc
RF
3037 local $SIG{__DIE__};
3038 local $SIG{__WARN__};
69893cff
RGS
3039
3040 # Is it valid Perl?
e22ea7cc
RF
3041 unless ( eval "sub { s\a$k\a$v\a }; 1" ) {
3042
69893cff 3043 # Nope. Bad alias. Say so and get out.
e22ea7cc
RF
3044 print $OUT "Can't alias $k to $v: $@\n";
3045 delete $alias{$k};
3046 next CMD;
3047 }
3048
69893cff 3049 # We'll only list the new one.
e22ea7cc 3050 @keys = ($k);
69893cff
RGS
3051 } ## end elsif (my ($k, $v) = ($cmd...
3052
3053 # The argument is the alias to list.
e22ea7cc
RF
3054 else {
3055 @keys = ($cmd);
3056 }
69893cff
RGS
3057
3058 # List aliases.
e22ea7cc
RF
3059 for my $k (@keys) {
3060
98dc9551 3061 # Messy metaquoting: Trim the substitution code off.
69893cff
RGS
3062 # We use control-G as the delimiter because it's not
3063 # likely to appear in the alias.
e22ea7cc
RF
3064 if ( ( my $v = $alias{$k} ) =~ s\as\a$k\a(.*)\a$\a1\a ) {
3065
69893cff 3066 # Print the alias.
e22ea7cc
RF
3067 print $OUT "$k\t= $1\n";
3068 }
3069 elsif ( defined $alias{$k} ) {
3070
69893cff 3071 # Couldn't trim it off; just print the alias code.
e22ea7cc
RF
3072 print $OUT "$k\t$alias{$k}\n";
3073 }
3074 else {
3075
69893cff 3076 # No such, dude.
e22ea7cc
RF
3077 print "No alias for $k\n";
3078 }
69893cff 3079 } ## end for my $k (@keys)
e22ea7cc 3080 next CMD;
ef18ae63 3081 }
69893cff
RGS
3082
3083=head4 C<source> - read commands from a file.
3084
3085Opens a lexical filehandle and stacks it on C<@cmdfhs>; C<DB::readline> will
3086pick it up.
3087
3088=cut
3089
e22ea7cc 3090 # source - read commands from a file (or pipe!) and execute.
ef18ae63
SF
3091 if (my ($sourced_fn) = $cmd =~ /\Asource\s+(.*\S)/) {
3092 if ( open my $fh, $sourced_fn ) {
e22ea7cc 3093
69893cff 3094 # Opened OK; stick it in the list of file handles.
e22ea7cc
RF
3095 push @cmdfhs, $fh;
3096 }
3097 else {
3098
3099 # Couldn't open it.
ef18ae63 3100 &warn("Can't execute '$sourced_fn': $!\n");
e22ea7cc
RF
3101 }
3102 next CMD;
ef18ae63 3103 }
69893cff 3104
ef18ae63
SF
3105 if (my ($which_cmd, $position)
3106 = $cmd =~ /^(enable|disable)\s+(\S+)\s*$/) {
e09195af
SF
3107
3108 my ($fn, $line_num);
3109 if ($position =~ m{\A\d+\z})
3110 {
3111 $fn = $filename;
3112 $line_num = $position;
3113 }
ef18ae63
SF
3114 elsif (my ($new_fn, $new_line_num)
3115 = $position =~ m{\A(.*):(\d+)\z}) {
3116 ($fn, $line_num) = ($new_fn, $new_line_num);
e09195af
SF
3117 }
3118 else
3119 {
3120 &warn("Wrong spec for enable/disable argument.\n");
3121 }
3122
3123 if (defined($fn)) {
3124 if (_has_breakpoint_data_ref($fn, $line_num)) {
3125 _set_breakpoint_enabled_status($fn, $line_num,
ef18ae63 3126 ($which_cmd eq 'enable' ? 1 : '')
e09195af
SF
3127 );
3128 }
3129 else {
3130 &warn("No breakpoint set at ${fn}:${line_num}\n");
3131 }
3132 }
3133
3134 next CMD;
ef18ae63 3135 }
e09195af 3136
69893cff
RGS
3137=head4 C<save> - send current history to a file
3138
3139Takes the complete history, (not the shrunken version you see with C<H>),
3140and saves it to the given filename, so it can be replayed using C<source>.
3141
3142Note that all C<^(save|source)>'s are commented out with a view to minimise recursion.
3143
3144=cut
3145
3146 # save source - write commands to a file for later use
ef18ae63
SF
3147 if (my ($new_fn) = $cmd =~ /\Asave\s*(.*)\z/) {
3148 my $filename = $new_fn || '.perl5dbrc'; # default?
3149 if ( open my $fh, '>', $filename ) {
e22ea7cc
RF
3150
3151 # chomp to remove extraneous newlines from source'd files
3152 chomp( my @truelist =
3153 map { m/^\s*(save|source)/ ? "#$_" : $_ }
3154 @truehist );
3155 print $fh join( "\n", @truelist );
69893cff 3156 print "commands saved in $file\n";
e22ea7cc
RF
3157 }
3158 else {
ef18ae63 3159 &warn("Can't save debugger commands in '$new_fn': $!\n");
69893cff
RGS
3160 }
3161 next CMD;
ef18ae63 3162 }
69893cff 3163
7fddc82f
RF
3164=head4 C<R> - restart
3165
ef18ae63 3166Restart the debugger session.
7fddc82f
RF
3167
3168=head4 C<rerun> - rerun the current session
3169
3170Return to any given position in the B<true>-history list
3171
3172=cut
3173
3174 # R - restart execution.
3175 # rerun - controlled restart execution.
ff41e38d
SF
3176 if (my ($cmd_cmd, $cmd_params) =
3177 $cmd =~ /\A((?:R)|(?:rerun\s*(.*)))\z/) {
3178 my @args = ($cmd_cmd eq 'R' ? restart() : rerun($cmd_params));
7fddc82f 3179
ca28b541
AP
3180 # Close all non-system fds for a clean restart. A more
3181 # correct method would be to close all fds that were not
3182 # open when the process started, but this seems to be
3183 # hard. See "debugger 'R'estart and open database
3184 # connections" on p5p.
3185
47d3bbda 3186 my $max_fd = 1024; # default if POSIX can't be loaded
ca28b541 3187 if (eval { require POSIX }) {
5332cc68 3188 eval { $max_fd = POSIX::sysconf(POSIX::_SC_OPEN_MAX()) };
ca28b541
AP
3189 }
3190
3191 if (defined $max_fd) {
3192 foreach ($^F+1 .. $max_fd-1) {
3193 next unless open FD_TO_CLOSE, "<&=$_";
3194 close(FD_TO_CLOSE);
3195 }
3196 }
3197
7fddc82f
RF
3198 # And run Perl again. We use exec() to keep the
3199 # PID stable (and that way $ini_pids is still valid).
3200 exec(@args) || print $OUT "exec failed: $!\n";
3201
3202 last CMD;
ff41e38d 3203 }
7fddc82f 3204
69893cff
RGS
3205=head4 C<|, ||> - pipe output through the pager.
3206
be9a9b1d 3207For C<|>, we save C<OUT> (the debugger's output filehandle) and C<STDOUT>
69893cff
RGS
3208(the program's standard output). For C<||>, we only save C<OUT>. We open a
3209pipe to the pager (restoring the output filehandles if this fails). If this
b570d64b 3210is the C<|> command, we also set up a C<SIGPIPE> handler which will simply
69893cff
RGS
3211set C<$signal>, sending us back into the debugger.
3212
3213We then trim off the pipe symbols and C<redo> the command loop at the
3214C<PIPE> label, causing us to evaluate the command in C<$cmd> without
3215reading another.
3216
3217=cut
3218
3219 # || - run command in the pager, with output to DB::OUT.
ff41e38d 3220 if ($cmd =~ m#\A\|\|?\s*[^|]#) {
e22ea7cc
RF
3221 if ( $pager =~ /^\|/ ) {
3222
69893cff 3223 # Default pager is into a pipe. Redirect I/O.
e22ea7cc
RF
3224 open( SAVEOUT, ">&STDOUT" )
3225 || &warn("Can't save STDOUT");
3226 open( STDOUT, ">&OUT" )
3227 || &warn("Can't redirect STDOUT");
69893cff 3228 } ## end if ($pager =~ /^\|/)
e22ea7cc
RF
3229 else {
3230
69893cff 3231 # Not into a pipe. STDOUT is safe.
e22ea7cc
RF
3232 open( SAVEOUT, ">&OUT" ) || &warn("Can't save DB::OUT");
3233 }
69893cff
RGS
3234
3235 # Fix up environment to record we have less if so.
e22ea7cc
RF
3236 fix_less();
3237
3238 unless ( $piped = open( OUT, $pager ) ) {
69893cff 3239
69893cff 3240 # Couldn't open pipe to pager.
1f874cb6 3241 &warn("Can't pipe output to '$pager'");
e22ea7cc
RF
3242 if ( $pager =~ /^\|/ ) {
3243
69893cff 3244 # Redirect I/O back again.
e22ea7cc
RF
3245 open( OUT, ">&STDOUT" ) # XXX: lost message
3246 || &warn("Can't restore DB::OUT");
3247 open( STDOUT, ">&SAVEOUT" )
3248 || &warn("Can't restore STDOUT");
3249 close(SAVEOUT);
69893cff 3250 } ## end if ($pager =~ /^\|/)
e22ea7cc
RF
3251 else {
3252
69893cff 3253 # Redirect I/O. STDOUT already safe.
e22ea7cc
RF
3254 open( OUT, ">&STDOUT" ) # XXX: lost message
3255 || &warn("Can't restore DB::OUT");
3256 }
3257 next CMD;
69893cff
RGS
3258 } ## end unless ($piped = open(OUT,...
3259
3260 # Set up broken-pipe handler if necessary.
e22ea7cc
RF
3261 $SIG{PIPE} = \&DB::catch
3262 if $pager =~ /^\|/
3263 && ( "" eq $SIG{PIPE} || "DEFAULT" eq $SIG{PIPE} );
69893cff 3264
70c9432b
SF
3265 OUT->autoflush(1);
3266 # Save current filehandle, and put it back.
e22ea7cc 3267 $selected = select(OUT);
69893cff 3268 # Don't put it back if pager was a pipe.
e22ea7cc 3269 select($selected), $selected = "" unless $cmd =~ /^\|\|/;
69893cff
RGS
3270
3271 # Trim off the pipe symbols and run the command now.
ff41e38d 3272 $cmd =~ s#\A\|+\s*##;
e22ea7cc 3273 redo PIPE;
ff41e38d 3274 }
69893cff
RGS
3275
3276=head3 END OF COMMAND PARSING
3277
ff41e38d
SF
3278Anything left in C<$cmd> at this point is a Perl expression that we want to
3279evaluate. We'll always evaluate in the user's context, and fully qualify
69893cff
RGS
3280any variables we might want to address in the C<DB> package.
3281
3282=cut
3283
3284 # t - turn trace on.
ff41e38d
SF
3285 if ($cmd =~ s#\At\s+(\d+)?#\$DB::trace |= 1;\n#) {
3286 my $trace_arg = $1;
3287 $trace_to_depth = $trace_arg ? $stack_depth||0 + $1 : 1E9;
3288 }
69893cff
RGS
3289
3290 # s - single-step. Remember the last command was 's'.
ff41e38d
SF
3291 if ($cmd =~ s/\As\s/\$DB::single = 1;\n/) {
3292 $laststep = 's';
3293 }
69893cff
RGS
3294
3295 # n - single-step, but not into subs. Remember last command
e22ea7cc 3296 # was 'n'.
ff41e38d
SF
3297 if ($cmd =~ s#\An\s#\$DB::single = 2;\n#) {
3298 $laststep = 'n';
3299 }
69893cff 3300
e22ea7cc 3301 } # PIPE:
69893cff 3302
e22ea7cc 3303 # Make sure the flag that says "the debugger's running" is
69893cff 3304 # still on, to make sure we get control again.
e22ea7cc 3305 $evalarg = "\$^D = \$^D | \$DB::db_stop;\n$cmd";
69893cff
RGS
3306
3307 # Run *our* eval that executes in the caller's context.
7c54f46a 3308 DB::eval();
69893cff
RGS
3309
3310 # Turn off the one-time-dump stuff now.
e22ea7cc
RF
3311 if ($onetimeDump) {
3312 $onetimeDump = undef;
69893cff 3313 $onetimedumpDepth = undef;
e22ea7cc
RF
3314 }
3315 elsif ( $term_pid == $$ ) {
8380a245 3316 eval { # May run under miniperl, when not available...
c7e68384
IZ
3317 STDOUT->flush();
3318 STDERR->flush();
8380a245 3319 };
e22ea7cc 3320
69893cff 3321 # XXX If this is the master pid, print a newline.
8380a245 3322 print {$OUT} "\n";
e22ea7cc
RF
3323 }
3324 } ## end while (($term || &setterm...
69893cff
RGS
3325
3326=head3 POST-COMMAND PROCESSING
3327
3328After each command, we check to see if the command output was piped anywhere.
3329If so, we go through the necessary code to unhook the pipe and go back to
3330our standard filehandles for input and output.
3331
3332=cut
3333
e22ea7cc 3334 continue { # CMD:
69893cff
RGS
3335
3336 # At the end of every command:
e22ea7cc
RF
3337 if ($piped) {
3338
69893cff 3339 # Unhook the pipe mechanism now.
e22ea7cc
RF
3340 if ( $pager =~ /^\|/ ) {
3341
69893cff 3342 # No error from the child.
e22ea7cc 3343 $? = 0;
69893cff 3344
e22ea7cc
RF
3345 # we cannot warn here: the handle is missing --tchrist
3346 close(OUT) || print SAVEOUT "\nCan't close DB::OUT\n";
69893cff 3347
e22ea7cc 3348 # most of the $? crud was coping with broken cshisms
69893cff 3349 # $? is explicitly set to 0, so this never runs.
e22ea7cc 3350 if ($?) {
1f874cb6 3351 print SAVEOUT "Pager '$pager' failed: ";
e22ea7cc
RF
3352 if ( $? == -1 ) {
3353 print SAVEOUT "shell returned -1\n";
3354 }
3355 elsif ( $? >> 8 ) {
3356 print SAVEOUT ( $? & 127 )
3357 ? " (SIG#" . ( $? & 127 ) . ")"
3358 : "", ( $? & 128 ) ? " -- core dumped" : "", "\n";
3359 }
3360 else {
3361 print SAVEOUT "status ", ( $? >> 8 ), "\n";
3362 }
69893cff
RGS
3363 } ## end if ($?)
3364
e22ea7cc 3365 # Reopen filehandle for our output (if we can) and
69893cff 3366 # restore STDOUT (if we can).
e22ea7cc
RF
3367 open( OUT, ">&STDOUT" ) || &warn("Can't restore DB::OUT");
3368 open( STDOUT, ">&SAVEOUT" )
3369 || &warn("Can't restore STDOUT");
69893cff
RGS
3370
3371 # Turn off pipe exception handler if necessary.
e22ea7cc 3372 $SIG{PIPE} = "DEFAULT" if $SIG{PIPE} eq \&DB::catch;
69893cff 3373
e22ea7cc
RF
3374 # Will stop ignoring SIGPIPE if done like nohup(1)
3375 # does SIGINT but Perl doesn't give us a choice.
69893cff 3376 } ## end if ($pager =~ /^\|/)
e22ea7cc
RF
3377 else {
3378
69893cff 3379 # Non-piped "pager". Just restore STDOUT.
e22ea7cc
RF
3380 open( OUT, ">&SAVEOUT" ) || &warn("Can't restore DB::OUT");
3381 }
69893cff
RGS
3382
3383 # Close filehandle pager was using, restore the normal one
3384 # if necessary,
3385 close(SAVEOUT);
e22ea7cc 3386 select($selected), $selected = "" unless $selected eq "";
69893cff
RGS
3387
3388 # No pipes now.
e22ea7cc 3389 $piped = "";
69893cff 3390 } ## end if ($piped)
e22ea7cc 3391 } # CMD:
69893cff
RGS
3392
3393=head3 COMMAND LOOP TERMINATION
3394
3395When commands have finished executing, we come here. If the user closed the
3396input filehandle, we turn on C<$fall_off_end> to emulate a C<q> command. We
3397evaluate any post-prompt items. We restore C<$@>, C<$!>, C<$^E>, C<$,>, C<$/>,
3398C<$\>, and C<$^W>, and return a null list as expected by the Perl interpreter.
3399The interpreter will then execute the next line and then return control to us
3400again.
3401
3402=cut
3403
3404 # No more commands? Quit.
1f874cb6 3405 $fall_off_end = 1 unless defined $cmd; # Emulate 'q' on EOF
69893cff
RGS
3406
3407 # Evaluate post-prompt commands.
e22ea7cc 3408 foreach $evalarg (@$post) {
7c54f46a 3409 DB::eval();
e22ea7cc
RF
3410 }
3411 } # if ($single || $signal)
69893cff
RGS
3412
3413 # Put the user's globals back where you found them.
e22ea7cc 3414 ( $@, $!, $^E, $,, $/, $\, $^W ) = @saved;
69893cff
RGS
3415 ();
3416} ## end sub DB
3417
22fc883d
SF
3418package DB::Obj;
3419
3420sub new {
3421 my $class = shift;
3422
3423 my $self = bless {}, $class;
3424
3425 $self->_init(@_);
3426
3427 return $self;
3428}
3429
3430sub _init {
3431 my ($self, $args) = @_;
3432
3433 %{$self} = (%$self, %$args);
3434
3435 return;
3436}
3437
3438{
3439 no strict 'refs';
3440 foreach my $slot_name (qw(after explicit_stop infix position prefix)) {
3441 my $slot = $slot_name;
3442 *{$slot} = sub {
3443 my $self = shift;
3444
3445 if (@_) {
3446 ${ $self->{$slot} } = shift;
3447 }
3448
3449 return ${ $self->{$slot} };
3450 };
8def6eff
SF
3451
3452 *{"append_to_$slot"} = sub {
3453 my $self = shift;
3454 my $s = shift;
3455
3456 return $self->$slot($self->$slot . $s);
3457 };
22fc883d
SF
3458 }
3459}
3460
3461sub _DB_on_init__initialize_globals
3462{
3463 my $self = shift;
3464
3465 # Check for whether we should be running continuously or not.
3466 # _After_ the perl program is compiled, $single is set to 1:
3467 if ( $DB::single and not $DB::second_time++ ) {
3468
3469 # Options say run non-stop. Run until we get an interrupt.
3470 if ($DB::runnonstop) { # Disable until signal
3471 # If there's any call stack in place, turn off single
3472 # stepping into subs throughout the stack.
3473 for my $i (0 .. $DB::stack_depth) {
3474 $DB::stack[ $i ] &= ~1;
3475 }
3476
3477 # And we are now no longer in single-step mode.
3478 $DB::single = 0;
3479
3480 # If we simply returned at this point, we wouldn't get
3481 # the trace info. Fall on through.
3482 # return;
3483 } ## end if ($runnonstop)
3484
3485 elsif ($DB::ImmediateStop) {
3486
3487 # We are supposed to stop here; XXX probably a break.
3488 $DB::ImmediateStop = 0; # We've processed it; turn it off
3489 $DB::signal = 1; # Simulate an interrupt to force
3490 # us into the command loop
3491 }
3492 } ## end if ($single and not $second_time...
3493
3494 # If we're in single-step mode, or an interrupt (real or fake)
3495 # has occurred, turn off non-stop mode.
3496 $DB::runnonstop = 0 if $DB::single or $DB::signal;
3497
3498 return;
3499}
3500
3501sub _DB__handle_watch_expressions
3502{
3503 my $self = shift;
3504
3505 if ( $DB::trace & 2 ) {
3506 for my $n (0 .. $#DB::to_watch) {
3507 $DB::evalarg = $DB::to_watch[$n];
3508 local $DB::onetimeDump; # Tell DB::eval() to not output results
3509
3510 # Fix context DB::eval() wants to return an array, but
3511 # we need a scalar here.
7c54f46a 3512 my ($val) = join( "', '", DB::eval() );
22fc883d
SF
3513 $val = ( ( defined $val ) ? "'$val'" : 'undef' );
3514
3515 # Did it change?
3516 if ( $val ne $DB::old_watch[$n] ) {
3517
3518 # Yep! Show the difference, and fake an interrupt.
3519 $DB::signal = 1;
3520 print {$DB::OUT} <<EOP;
3521Watchpoint $n:\t$DB::to_watch[$n] changed:
3522 old value:\t$DB::old_watch[$n]
3523 new value:\t$val
3524EOP
3525 $DB::old_watch[$n] = $val;
3526 } ## end if ($val ne $old_watch...
3527 } ## end for my $n (0 ..
3528 } ## end if ($trace & 2)
3529
3530 return;
3531}
3532
ad46ac70
SF
3533sub _my_print_lineinfo
3534{
3535 my ($self, $i, $incr_pos) = @_;
3536
3537 if ($DB::frame) {
3538 # Print it indented if tracing is on.
3539 DB::print_lineinfo( ' ' x $DB::stack_depth,
3540 "$i:\t$DB::dbline[$i]" . $self->after );
3541 }
3542 else {
3543 DB::depth_print_lineinfo($self->explicit_stop, $incr_pos);
3544 }
3545}
3546
44a07e3e
SF
3547sub _curr_line {
3548 return $DB::dbline[$DB::line];
3549}
3550
22fc883d
SF
3551sub _DB__grab_control
3552{
3553 my $self = shift;
3554
3555 # Yes, grab control.
3556 if ($DB::slave_editor) {
3557
3558 # Tell the editor to update its position.
3559 $self->position("\032\032${DB::filename}:${DB::line}:0\n");
3560 DB::print_lineinfo($self->position());
3561 }
3562
3563=pod
3564
3565Special check: if we're in package C<DB::fake>, we've gone through the
3566C<END> block at least once. We set up everything so that we can continue
3567to enter commands and have a valid context to be in.
3568
3569=cut
3570
3571 elsif ( $DB::package eq 'DB::fake' ) {
3572
3573 # Fallen off the end already.
3574 if (!$DB::term) {
3575 DB::setterm();
3576 }
3577
3578 DB::print_help(<<EOP);
3579Debugged program terminated. Use B<q> to quit or B<R> to restart,
3580use B<o> I<inhibit_exit> to avoid stopping after program termination,
3581B<h q>, B<h R> or B<h o> to get additional info.
3582EOP
3583
3584 # Set the DB::eval context appropriately.
3585 $DB::package = 'main';
3586 $DB::usercontext = DB::_calc_usercontext($DB::package);
3587 } ## end elsif ($package eq 'DB::fake')
3588
3589=pod
3590
3591If the program hasn't finished executing, we scan forward to the
3592next executable line, print that out, build the prompt from the file and line
3593number information, and print that.
3594
3595=cut
3596
3597 else {
3598
3599
3600 # Still somewhere in the midst of execution. Set up the
3601 # debugger prompt.
3602 $DB::sub =~ s/\'/::/; # Swap Perl 4 package separators (') to
3603 # Perl 5 ones (sorry, we don't print Klingon
3604 #module names)
3605
3606 $self->prefix($DB::sub =~ /::/ ? "" : ($DB::package . '::'));
8def6eff 3607 $self->append_to_prefix( "$DB::sub(${DB::filename}:" );
44a07e3e 3608 $self->after( $self->_curr_line =~ /\n$/ ? '' : "\n" );
22fc883d
SF
3609