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[perl5db] More refactoring.
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e22ea7cc 1
b570d64b 2=head1 NAME
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be9a9b1d 4perl5db.pl - the perl debugger
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5
6=head1 SYNOPSIS
7
8 perl -d your_Perl_script
9
10=head1 DESCRIPTION
11
12C<perl5db.pl> is the perl debugger. It is loaded automatically by Perl when
13you invoke a script with C<perl -d>. This documentation tries to outline the
14structure and services provided by C<perl5db.pl>, and to describe how you
15can use them.
16
17=head1 GENERAL NOTES
18
19The debugger can look pretty forbidding to many Perl programmers. There are
20a number of reasons for this, many stemming out of the debugger's history.
21
22When the debugger was first written, Perl didn't have a lot of its nicer
23features - no references, no lexical variables, no closures, no object-oriented
24programming. So a lot of the things one would normally have done using such
b570d64b 25features was done using global variables, globs and the C<local()> operator
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26in creative ways.
27
28Some of these have survived into the current debugger; a few of the more
29interesting and still-useful idioms are noted in this section, along with notes
30on the comments themselves.
31
32=head2 Why not use more lexicals?
33
34Experienced Perl programmers will note that the debugger code tends to use
35mostly package globals rather than lexically-scoped variables. This is done
36to allow a significant amount of control of the debugger from outside the
b570d64b 37debugger itself.
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38
39Unfortunately, though the variables are accessible, they're not well
40documented, so it's generally been a decision that hasn't made a lot of
41difference to most users. Where appropriate, comments have been added to
42make variables more accessible and usable, with the understanding that these
be9a9b1d 43I<are> debugger internals, and are therefore subject to change. Future
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44development should probably attempt to replace the globals with a well-defined
45API, but for now, the variables are what we've got.
46
47=head2 Automated variable stacking via C<local()>
48
b570d64b 49As you may recall from reading C<perlfunc>, the C<local()> operator makes a
69893cff 50temporary copy of a variable in the current scope. When the scope ends, the
b570d64b 51old copy is restored. This is often used in the debugger to handle the
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52automatic stacking of variables during recursive calls:
53
54 sub foo {
55 local $some_global++;
56
57 # Do some stuff, then ...
58 return;
59 }
60
61What happens is that on entry to the subroutine, C<$some_global> is localized,
b570d64b 62then altered. When the subroutine returns, Perl automatically undoes the
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63localization, restoring the previous value. Voila, automatic stack management.
64
b570d64b 65The debugger uses this trick a I<lot>. Of particular note is C<DB::eval>,
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66which lets the debugger get control inside of C<eval>'ed code. The debugger
67localizes a saved copy of C<$@> inside the subroutine, which allows it to
68keep C<$@> safe until it C<DB::eval> returns, at which point the previous
b570d64b 69value of C<$@> is restored. This makes it simple (well, I<simpler>) to keep
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70track of C<$@> inside C<eval>s which C<eval> other C<eval's>.
71
72In any case, watch for this pattern. It occurs fairly often.
73
74=head2 The C<^> trick
75
b570d64b 76This is used to cleverly reverse the sense of a logical test depending on
69893cff 77the value of an auxiliary variable. For instance, the debugger's C<S>
b570d64b 78(search for subroutines by pattern) allows you to negate the pattern
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79like this:
80
81 # Find all non-'foo' subs:
b570d64b 82 S !/foo/
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83
84Boolean algebra states that the truth table for XOR looks like this:
85
86=over 4
87
b570d64b 88=item * 0 ^ 0 = 0
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89
90(! not present and no match) --> false, don't print
91
b570d64b 92=item * 0 ^ 1 = 1
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93
94(! not present and matches) --> true, print
95
b570d64b 96=item * 1 ^ 0 = 1
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97
98(! present and no match) --> true, print
99
b570d64b 100=item * 1 ^ 1 = 0
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101
102(! present and matches) --> false, don't print
103
104=back
105
106As you can see, the first pair applies when C<!> isn't supplied, and
be9a9b1d 107the second pair applies when it is. The XOR simply allows us to
b570d64b 108compact a more complicated if-then-elseif-else into a more elegant
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109(but perhaps overly clever) single test. After all, it needed this
110explanation...
111
112=head2 FLAGS, FLAGS, FLAGS
113
114There is a certain C programming legacy in the debugger. Some variables,
be9a9b1d 115such as C<$single>, C<$trace>, and C<$frame>, have I<magical> values composed
69893cff 116of 1, 2, 4, etc. (powers of 2) OR'ed together. This allows several pieces
b570d64b 117of state to be stored independently in a single scalar.
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118
119A test like
120
121 if ($scalar & 4) ...
122
b570d64b 123is checking to see if the appropriate bit is on. Since each bit can be
69893cff 124"addressed" independently in this way, C<$scalar> is acting sort of like
b570d64b 125an array of bits. Obviously, since the contents of C<$scalar> are just a
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126bit-pattern, we can save and restore it easily (it will just look like
127a number).
128
129The problem, is of course, that this tends to leave magic numbers scattered
b570d64b 130all over your program whenever a bit is set, cleared, or checked. So why do
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131it?
132
133=over 4
134
be9a9b1d 135=item *
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be9a9b1d 137First, doing an arithmetical or bitwise operation on a scalar is
69893cff 138just about the fastest thing you can do in Perl: C<use constant> actually
be9a9b1d 139creates a subroutine call, and array and hash lookups are much slower. Is
b570d64b 140this over-optimization at the expense of readability? Possibly, but the
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141debugger accesses these variables a I<lot>. Any rewrite of the code will
142probably have to benchmark alternate implementations and see which is the
b570d64b 143best balance of readability and speed, and then document how it actually
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144works.
145
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146=item *
147
b570d64b 148Second, it's very easy to serialize a scalar number. This is done in
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149the restart code; the debugger state variables are saved in C<%ENV> and then
150restored when the debugger is restarted. Having them be just numbers makes
b570d64b 151this trivial.
69893cff 152
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153=item *
154
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155Third, some of these variables are being shared with the Perl core
156smack in the middle of the interpreter's execution loop. It's much faster for
157a C program (like the interpreter) to check a bit in a scalar than to access
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158several different variables (or a Perl array).
159
160=back
161
162=head2 What are those C<XXX> comments for?
163
164Any comment containing C<XXX> means that the comment is either somewhat
b570d64b 165speculative - it's not exactly clear what a given variable or chunk of
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166code is doing, or that it is incomplete - the basics may be clear, but the
167subtleties are not completely documented.
168
169Send in a patch if you can clear up, fill out, or clarify an C<XXX>.
170
b570d64b 171=head1 DATA STRUCTURES MAINTAINED BY CORE
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172
173There are a number of special data structures provided to the debugger by
174the Perl interpreter.
175
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176The array C<@{$main::{'_<'.$filename}}> (aliased locally to C<@dbline>
177via glob assignment) contains the text from C<$filename>, with each
178element corresponding to a single line of C<$filename>. Additionally,
179breakable lines will be dualvars with the numeric component being the
180memory address of a COP node. Non-breakable lines are dualvar to 0.
69893cff 181
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182The hash C<%{'_<'.$filename}> (aliased locally to C<%dbline> via glob
183assignment) contains breakpoints and actions. The keys are line numbers;
184you can set individual values, but not the whole hash. The Perl interpreter
69893cff 185uses this hash to determine where breakpoints have been set. Any true value is
be9a9b1d 186considered to be a breakpoint; C<perl5db.pl> uses C<$break_condition\0$action>.
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187Values are magical in numeric context: 1 if the line is breakable, 0 if not.
188
ef18ae63 189The scalar C<${"_<$filename"}> simply contains the string C<<< _<$filename> >>>.
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190This is also the case for evaluated strings that contain subroutines, or
191which are currently being executed. The $filename for C<eval>ed strings looks
d24ca0c5 192like C<(eval 34).
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193
194=head1 DEBUGGER STARTUP
195
196When C<perl5db.pl> starts, it reads an rcfile (C<perl5db.ini> for
197non-interactive sessions, C<.perldb> for interactive ones) that can set a number
198of options. In addition, this file may define a subroutine C<&afterinit>
b570d64b 199that will be executed (in the debugger's context) after the debugger has
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200initialized itself.
201
b570d64b 202Next, it checks the C<PERLDB_OPTS> environment variable and treats its
be9a9b1d 203contents as the argument of a C<o> command in the debugger.
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204
205=head2 STARTUP-ONLY OPTIONS
206
207The following options can only be specified at startup.
208To set them in your rcfile, add a call to
209C<&parse_options("optionName=new_value")>.
210
211=over 4
212
b570d64b 213=item * TTY
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214
215the TTY to use for debugging i/o.
216
b570d64b 217=item * noTTY
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218
219if set, goes in NonStop mode. On interrupt, if TTY is not set,
b0e77abc 220uses the value of noTTY or F<$HOME/.perldbtty$$> to find TTY using
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221Term::Rendezvous. Current variant is to have the name of TTY in this
222file.
223
b570d64b 224=item * ReadLine
69893cff 225
5561b870 226if false, a dummy ReadLine is used, so you can debug
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227ReadLine applications.
228
b570d64b 229=item * NonStop
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230
231if true, no i/o is performed until interrupt.
232
b570d64b 233=item * LineInfo
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234
235file or pipe to print line number info to. If it is a
236pipe, a short "emacs like" message is used.
237
b570d64b 238=item * RemotePort
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239
240host:port to connect to on remote host for remote debugging.
241
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242=item * HistFile
243
244file to store session history to. There is no default and so no
245history file is written unless this variable is explicitly set.
246
247=item * HistSize
248
249number of commands to store to the file specified in C<HistFile>.
250Default is 100.
251
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252=back
253
254=head3 SAMPLE RCFILE
255
256 &parse_options("NonStop=1 LineInfo=db.out");
257 sub afterinit { $trace = 1; }
258
259The script will run without human intervention, putting trace
260information into C<db.out>. (If you interrupt it, you had better
be9a9b1d 261reset C<LineInfo> to something I<interactive>!)
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262
263=head1 INTERNALS DESCRIPTION
264
265=head2 DEBUGGER INTERFACE VARIABLES
266
267Perl supplies the values for C<%sub>. It effectively inserts
be9a9b1d 268a C<&DB::DB();> in front of each place that can have a
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269breakpoint. At each subroutine call, it calls C<&DB::sub> with
270C<$DB::sub> set to the called subroutine. It also inserts a C<BEGIN
271{require 'perl5db.pl'}> before the first line.
272
273After each C<require>d file is compiled, but before it is executed, a
274call to C<&DB::postponed($main::{'_<'.$filename})> is done. C<$filename>
275is the expanded name of the C<require>d file (as found via C<%INC>).
276
277=head3 IMPORTANT INTERNAL VARIABLES
278
279=head4 C<$CreateTTY>
280
281Used to control when the debugger will attempt to acquire another TTY to be
b570d64b 282used for input.
69893cff 283
b570d64b 284=over
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285
286=item * 1 - on C<fork()>
287
288=item * 2 - debugger is started inside debugger
289
290=item * 4 - on startup
291
292=back
293
294=head4 C<$doret>
295
296The value -2 indicates that no return value should be printed.
297Any other positive value causes C<DB::sub> to print return values.
298
299=head4 C<$evalarg>
300
301The item to be eval'ed by C<DB::eval>. Used to prevent messing with the current
302contents of C<@_> when C<DB::eval> is called.
303
304=head4 C<$frame>
305
306Determines what messages (if any) will get printed when a subroutine (or eval)
b570d64b 307is entered or exited.
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308
309=over 4
310
311=item * 0 - No enter/exit messages
312
be9a9b1d 313=item * 1 - Print I<entering> messages on subroutine entry
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314
315=item * 2 - Adds exit messages on subroutine exit. If no other flag is on, acts like 1+2.
316
be9a9b1d 317=item * 4 - Extended messages: C<< <in|out> I<context>=I<fully-qualified sub name> from I<file>:I<line> >>. If no other flag is on, acts like 1+4.
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318
319=item * 8 - Adds parameter information to messages, and overloaded stringify and tied FETCH is enabled on the printed arguments. Ignored if C<4> is not on.
320
321=item * 16 - Adds C<I<context> return from I<subname>: I<value>> messages on subroutine/eval exit. Ignored if C<4> is is not on.
322
323=back
324
be9a9b1d 325To get everything, use C<$frame=30> (or C<o f=30> as a debugger command).
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326The debugger internally juggles the value of C<$frame> during execution to
327protect external modules that the debugger uses from getting traced.
328
329=head4 C<$level>
330
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331Tracks current debugger nesting level. Used to figure out how many
332C<E<lt>E<gt>> pairs to surround the line number with when the debugger
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333outputs a prompt. Also used to help determine if the program has finished
334during command parsing.
335
336=head4 C<$onetimeDump>
337
338Controls what (if anything) C<DB::eval()> will print after evaluating an
339expression.
340
341=over 4
342
343=item * C<undef> - don't print anything
344
345=item * C<dump> - use C<dumpvar.pl> to display the value returned
346
347=item * C<methods> - print the methods callable on the first item returned
348
349=back
350
351=head4 C<$onetimeDumpDepth>
352
be9a9b1d 353Controls how far down C<dumpvar.pl> will go before printing C<...> while
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354dumping a structure. Numeric. If C<undef>, print all levels.
355
356=head4 C<$signal>
357
358Used to track whether or not an C<INT> signal has been detected. C<DB::DB()>,
359which is called before every statement, checks this and puts the user into
360command mode if it finds C<$signal> set to a true value.
361
362=head4 C<$single>
363
364Controls behavior during single-stepping. Stacked in C<@stack> on entry to
365each subroutine; popped again at the end of each subroutine.
366
b570d64b 367=over 4
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368
369=item * 0 - run continuously.
370
be9a9b1d 371=item * 1 - single-step, go into subs. The C<s> command.
69893cff 372
be9a9b1d 373=item * 2 - single-step, don't go into subs. The C<n> command.
69893cff 374
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375=item * 4 - print current sub depth (turned on to force this when C<too much
376recursion> occurs.
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377
378=back
379
380=head4 C<$trace>
381
b570d64b 382Controls the output of trace information.
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383
384=over 4
385
386=item * 1 - The C<t> command was entered to turn on tracing (every line executed is printed)
387
388=item * 2 - watch expressions are active
389
390=item * 4 - user defined a C<watchfunction()> in C<afterinit()>
391
392=back
393
394=head4 C<$slave_editor>
395
3961 if C<LINEINFO> was directed to a pipe; 0 otherwise.
397
398=head4 C<@cmdfhs>
399
400Stack of filehandles that C<DB::readline()> will read commands from.
401Manipulated by the debugger's C<source> command and C<DB::readline()> itself.
402
403=head4 C<@dbline>
404
b570d64b 405Local alias to the magical line array, C<@{$main::{'_<'.$filename}}> ,
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406supplied by the Perl interpreter to the debugger. Contains the source.
407
408=head4 C<@old_watch>
409
410Previous values of watch expressions. First set when the expression is
411entered; reset whenever the watch expression changes.
412
413=head4 C<@saved>
414
415Saves important globals (C<$@>, C<$!>, C<$^E>, C<$,>, C<$/>, C<$\>, C<$^W>)
416so that the debugger can substitute safe values while it's running, and
417restore them when it returns control.
418
419=head4 C<@stack>
420
421Saves the current value of C<$single> on entry to a subroutine.
422Manipulated by the C<c> command to turn off tracing in all subs above the
423current one.
424
425=head4 C<@to_watch>
426
427The 'watch' expressions: to be evaluated before each line is executed.
428
429=head4 C<@typeahead>
430
431The typeahead buffer, used by C<DB::readline>.
432
433=head4 C<%alias>
434
435Command aliases. Stored as character strings to be substituted for a command
436entered.
437
438=head4 C<%break_on_load>
439
440Keys are file names, values are 1 (break when this file is loaded) or undef
441(don't break when it is loaded).
442
443=head4 C<%dbline>
444
be9a9b1d 445Keys are line numbers, values are C<condition\0action>. If used in numeric
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446context, values are 0 if not breakable, 1 if breakable, no matter what is
447in the actual hash entry.
448
449=head4 C<%had_breakpoints>
450
451Keys are file names; values are bitfields:
452
b570d64b 453=over 4
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454
455=item * 1 - file has a breakpoint in it.
456
457=item * 2 - file has an action in it.
458
459=back
460
461A zero or undefined value means this file has neither.
462
463=head4 C<%option>
464
465Stores the debugger options. These are character string values.
466
467=head4 C<%postponed>
468
469Saves breakpoints for code that hasn't been compiled yet.
470Keys are subroutine names, values are:
471
472=over 4
473
be9a9b1d 474=item * C<compile> - break when this sub is compiled
69893cff 475
be9a9b1d 476=item * C<< break +0 if <condition> >> - break (conditionally) at the start of this routine. The condition will be '1' if no condition was specified.
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477
478=back
479
480=head4 C<%postponed_file>
481
482This hash keeps track of breakpoints that need to be set for files that have
483not yet been compiled. Keys are filenames; values are references to hashes.
484Each of these hashes is keyed by line number, and its values are breakpoint
be9a9b1d 485definitions (C<condition\0action>).
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486
487=head1 DEBUGGER INITIALIZATION
488
489The debugger's initialization actually jumps all over the place inside this
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490package. This is because there are several BEGIN blocks (which of course
491execute immediately) spread through the code. Why is that?
69893cff 492
b570d64b 493The debugger needs to be able to change some things and set some things up
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494before the debugger code is compiled; most notably, the C<$deep> variable that
495C<DB::sub> uses to tell when a program has recursed deeply. In addition, the
496debugger has to turn off warnings while the debugger code is compiled, but then
497restore them to their original setting before the program being debugged begins
498executing.
499
500The first C<BEGIN> block simply turns off warnings by saving the current
501setting of C<$^W> and then setting it to zero. The second one initializes
502the debugger variables that are needed before the debugger begins executing.
b570d64b 503The third one puts C<$^X> back to its former value.
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504
505We'll detail the second C<BEGIN> block later; just remember that if you need
506to initialize something before the debugger starts really executing, that's
507where it has to go.
508
509=cut
510
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511package DB;
512
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513use strict;
514
c7e68384 515BEGIN {eval 'use IO::Handle'}; # Needed for flush only? breaks under miniperl
9eba6a4e 516
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517BEGIN {
518 require feature;
519 $^V =~ /^v(\d+\.\d+)/;
520 feature->import(":$1");
521}
522
54d04a52 523# Debugger for Perl 5.00x; perl5db.pl patch level:
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524use vars qw($VERSION $header);
525
b5afd346 526$VERSION = '1.39_04';
69893cff 527
e22ea7cc 528$header = "perl5db.pl version $VERSION";
d338d6fe 529
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530=head1 DEBUGGER ROUTINES
531
532=head2 C<DB::eval()>
533
534This function replaces straight C<eval()> inside the debugger; it simplifies
535the process of evaluating code in the user's context.
536
b570d64b 537The code to be evaluated is passed via the package global variable
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538C<$DB::evalarg>; this is done to avoid fiddling with the contents of C<@_>.
539
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540Before we do the C<eval()>, we preserve the current settings of C<$trace>,
541C<$single>, C<$^D> and C<$usercontext>. The latter contains the
542preserved values of C<$@>, C<$!>, C<$^E>, C<$,>, C<$/>, C<$\>, C<$^W> and the
543user's current package, grabbed when C<DB::DB> got control. This causes the
544proper context to be used when the eval is actually done. Afterward, we
545restore C<$trace>, C<$single>, and C<$^D>.
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546
547Next we need to handle C<$@> without getting confused. We save C<$@> in a
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548local lexical, localize C<$saved[0]> (which is where C<save()> will put
549C<$@>), and then call C<save()> to capture C<$@>, C<$!>, C<$^E>, C<$,>,
69893cff 550C<$/>, C<$\>, and C<$^W>) and set C<$,>, C<$/>, C<$\>, and C<$^W> to values
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551considered sane by the debugger. If there was an C<eval()> error, we print
552it on the debugger's output. If C<$onetimedump> is defined, we call
553C<dumpit> if it's set to 'dump', or C<methods> if it's set to
554'methods'. Setting it to something else causes the debugger to do the eval
555but not print the result - handy if you want to do something else with it
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556(the "watch expressions" code does this to get the value of the watch
557expression but not show it unless it matters).
558
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559In any case, we then return the list of output from C<eval> to the caller,
560and unwinding restores the former version of C<$@> in C<@saved> as well
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561(the localization of C<$saved[0]> goes away at the end of this scope).
562
563=head3 Parameters and variables influencing execution of DB::eval()
564
565C<DB::eval> isn't parameterized in the standard way; this is to keep the
566debugger's calls to C<DB::eval()> from mucking with C<@_>, among other things.
b570d64b 567The variables listed below influence C<DB::eval()>'s execution directly.
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568
569=over 4
570
571=item C<$evalarg> - the thing to actually be eval'ed
572
be9a9b1d 573=item C<$trace> - Current state of execution tracing
69893cff 574
be9a9b1d 575=item C<$single> - Current state of single-stepping
69893cff 576
b570d64b 577=item C<$onetimeDump> - what is to be displayed after the evaluation
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578
579=item C<$onetimeDumpDepth> - how deep C<dumpit()> should go when dumping results
580
581=back
582
583The following variables are altered by C<DB::eval()> during its execution. They
b570d64b 584are "stacked" via C<local()>, enabling recursive calls to C<DB::eval()>.
69893cff
RGS
585
586=over 4
587
588=item C<@res> - used to capture output from actual C<eval>.
589
590=item C<$otrace> - saved value of C<$trace>.
591
b570d64b 592=item C<$osingle> - saved value of C<$single>.
69893cff
RGS
593
594=item C<$od> - saved value of C<$^D>.
595
596=item C<$saved[0]> - saved value of C<$@>.
597
b570d64b 598=item $\ - for output of C<$@> if there is an evaluation error.
69893cff
RGS
599
600=back
601
602=head3 The problem of lexicals
603
604The context of C<DB::eval()> presents us with some problems. Obviously,
605we want to be 'sandboxed' away from the debugger's internals when we do
606the eval, but we need some way to control how punctuation variables and
b570d64b 607debugger globals are used.
69893cff
RGS
608
609We can't use local, because the code inside C<DB::eval> can see localized
610variables; and we can't use C<my> either for the same reason. The code
611in this routine compromises and uses C<my>.
612
613After this routine is over, we don't have user code executing in the debugger's
614context, so we can use C<my> freely.
615
616=cut
617
618############################################## Begin lexical danger zone
619
620# 'my' variables used here could leak into (that is, be visible in)
621# the context that the code being evaluated is executing in. This means that
622# the code could modify the debugger's variables.
623#
624# Fiddling with the debugger's context could be Bad. We insulate things as
625# much as we can.
626
6b24a4b7
SF
627use vars qw(
628 @args
629 %break_on_load
630 @cmdfhs
631 $CommandSet
632 $CreateTTY
633 $DBGR
634 @dbline
635 $dbline
636 %dbline
637 $dieLevel
638 $evalarg
639 $filename
640 $frame
641 $hist
642 $histfile
643 $histsize
644 $ImmediateStop
645 $IN
646 $inhibit_exit
647 @ini_INC
648 $ini_warn
649 $line
650 $maxtrace
651 $od
652 $onetimeDump
653 $onetimedumpDepth
654 %option
655 @options
656 $osingle
657 $otrace
658 $OUT
659 $packname
660 $pager
661 $post
662 %postponed
663 $prc
664 $pre
665 $pretype
666 $psh
667 @RememberOnROptions
668 $remoteport
669 @res
670 $rl
671 @saved
672 $signal
673 $signalLevel
674 $single
675 $start
676 $sub
677 %sub
678 $subname
679 $term
680 $trace
681 $usercontext
682 $warnLevel
683 $window
684);
685
686# Used to save @ARGV and extract any debugger-related flags.
687use vars qw(@ARGS);
688
689# Used to prevent multiple entries to diesignal()
690# (if for instance diesignal() itself dies)
691use vars qw($panic);
692
693# Used to prevent the debugger from running nonstop
694# after a restart
695use vars qw($second_time);
696
697sub _calc_usercontext {
698 my ($package) = @_;
699
700 # Cancel strict completely for the evaluated code, so the code
701 # the user evaluates won't be affected by it. (Shlomi Fish)
702 return 'no strict; ($@, $!, $^E, $,, $/, $\, $^W) = @saved;'
703 . "package $package;"; # this won't let them modify, alas
704}
705
c1051fcf 706sub eval {
69893cff 707
c1051fcf 708 # 'my' would make it visible from user code
e22ea7cc 709 # but so does local! --tchrist
69893cff 710 # Remember: this localizes @DB::res, not @main::res.
c1051fcf
IZ
711 local @res;
712 {
e22ea7cc
RF
713
714 # Try to keep the user code from messing with us. Save these so that
715 # even if the eval'ed code changes them, we can put them back again.
716 # Needed because the user could refer directly to the debugger's
69893cff
RGS
717 # package globals (and any 'my' variables in this containing scope)
718 # inside the eval(), and we want to try to stay safe.
e22ea7cc 719 local $otrace = $trace;
69893cff
RGS
720 local $osingle = $single;
721 local $od = $^D;
722
723 # Untaint the incoming eval() argument.
724 { ($evalarg) = $evalarg =~ /(.*)/s; }
725
e22ea7cc 726 # $usercontext built in DB::DB near the comment
69893cff
RGS
727 # "set up the context for DB::eval ..."
728 # Evaluate and save any results.
e22ea7cc 729 @res = eval "$usercontext $evalarg;\n"; # '\n' for nice recursive debug
69893cff
RGS
730
731 # Restore those old values.
732 $trace = $otrace;
733 $single = $osingle;
734 $^D = $od;
c1051fcf 735 }
69893cff
RGS
736
737 # Save the current value of $@, and preserve it in the debugger's copy
738 # of the saved precious globals.
c1051fcf 739 my $at = $@;
69893cff
RGS
740
741 # Since we're only saving $@, we only have to localize the array element
742 # that it will be stored in.
e22ea7cc 743 local $saved[0]; # Preserve the old value of $@
c1051fcf 744 eval { &DB::save };
69893cff
RGS
745
746 # Now see whether we need to report an error back to the user.
c1051fcf 747 if ($at) {
69893cff
RGS
748 local $\ = '';
749 print $OUT $at;
750 }
751
752 # Display as required by the caller. $onetimeDump and $onetimedumpDepth
753 # are package globals.
754 elsif ($onetimeDump) {
e22ea7cc
RF
755 if ( $onetimeDump eq 'dump' ) {
756 local $option{dumpDepth} = $onetimedumpDepth
757 if defined $onetimedumpDepth;
758 dumpit( $OUT, \@res );
759 }
760 elsif ( $onetimeDump eq 'methods' ) {
761 methods( $res[0] );
762 }
69893cff 763 } ## end elsif ($onetimeDump)
c1051fcf 764 @res;
69893cff
RGS
765} ## end sub eval
766
767############################################## End lexical danger zone
c1051fcf 768
e22ea7cc
RF
769# After this point it is safe to introduce lexicals.
770# The code being debugged will be executing in its own context, and
69893cff 771# can't see the inside of the debugger.
d338d6fe 772#
e22ea7cc 773# However, one should not overdo it: leave as much control from outside as
69893cff
RGS
774# possible. If you make something a lexical, it's not going to be addressable
775# from outside the debugger even if you know its name.
776
d338d6fe
PP
777# This file is automatically included if you do perl -d.
778# It's probably not useful to include this yourself.
779#
e22ea7cc 780# Before venturing further into these twisty passages, it is
2f7e9187
MS
781# wise to read the perldebguts man page or risk the ire of dragons.
782#
69893cff
RGS
783# (It should be noted that perldebguts will tell you a lot about
784# the underlying mechanics of how the debugger interfaces into the
785# Perl interpreter, but not a lot about the debugger itself. The new
786# comments in this code try to address this problem.)
787
d338d6fe 788# Note that no subroutine call is possible until &DB::sub is defined
36477c24 789# (for subroutines defined outside of the package DB). In fact the same is
d338d6fe 790# true if $deep is not defined.
055fd3a9
GS
791
792# Enhanced by ilya@math.ohio-state.edu (Ilya Zakharevich)
055fd3a9
GS
793
794# modified Perl debugger, to be run from Emacs in perldb-mode
795# Ray Lischner (uunet!mntgfx!lisch) as of 5 Nov 1990
796# Johan Vromans -- upgrade to 4.0 pl 10
797# Ilya Zakharevich -- patches after 5.001 (and some before ;-)
6fae1ad7 798########################################################################
d338d6fe 799
69893cff
RGS
800=head1 DEBUGGER INITIALIZATION
801
802The debugger starts up in phases.
803
804=head2 BASIC SETUP
805
806First, it initializes the environment it wants to run in: turning off
807warnings during its own compilation, defining variables which it will need
808to avoid warnings later, setting itself up to not exit when the program
809terminates, and defaulting to printing return values for the C<r> command.
810
811=cut
812
eda6e075 813# Needed for the statement after exec():
69893cff
RGS
814#
815# This BEGIN block is simply used to switch off warnings during debugger
98dc9551 816# compilation. Probably it would be better practice to fix the warnings,
69893cff 817# but this is how it's done at the moment.
eda6e075 818
e22ea7cc
RF
819BEGIN {
820 $ini_warn = $^W;
821 $^W = 0;
822} # Switch compilation warnings off until another BEGIN.
d12a4851 823
69893cff
RGS
824local ($^W) = 0; # Switch run-time warnings off during init.
825
2cbb2ee1
RGS
826=head2 THREADS SUPPORT
827
828If we are running under a threaded Perl, we require threads and threads::shared
829if the environment variable C<PERL5DB_THREADED> is set, to enable proper
830threaded debugger control. C<-dt> can also be used to set this.
831
832Each new thread will be announced and the debugger prompt will always inform
833you of each new thread created. It will also indicate the thread id in which
834we are currently running within the prompt like this:
835
836 [tid] DB<$i>
837
838Where C<[tid]> is an integer thread id and C<$i> is the familiar debugger
839command prompt. The prompt will show: C<[0]> when running under threads, but
840not actually in a thread. C<[tid]> is consistent with C<gdb> usage.
841
842While running under threads, when you set or delete a breakpoint (etc.), this
b570d64b 843will apply to all threads, not just the currently running one. When you are
2cbb2ee1
RGS
844in a currently executing thread, you will stay there until it completes. With
845the current implementation it is not currently possible to hop from one thread
846to another.
847
848The C<e> and C<E> commands are currently fairly minimal - see C<h e> and C<h E>.
849
850Note that threading support was built into the debugger as of Perl version
851C<5.8.6> and debugger version C<1.2.8>.
852
853=cut
854
855BEGIN {
856 # ensure we can share our non-threaded variables or no-op
857 if ($ENV{PERL5DB_THREADED}) {
858 require threads;
859 require threads::shared;
860 import threads::shared qw(share);
861 $DBGR;
862 share(\$DBGR);
863 lock($DBGR);
864 print "Threads support enabled\n";
865 } else {
866 *lock = sub(*) {};
867 *share = sub(*) {};
868 }
869}
870
2218c045
SF
871# These variables control the execution of 'dumpvar.pl'.
872{
873 package dumpvar;
874 use vars qw(
875 $hashDepth
876 $arrayDepth
877 $dumpDBFiles
878 $dumpPackages
879 $quoteHighBit
880 $printUndef
881 $globPrint
882 $usageOnly
883 );
884}
69893cff 885
2218c045
SF
886# used to control die() reporting in diesignal()
887{
888 package Carp;
889 use vars qw($CarpLevel);
890}
d338d6fe 891
422c59bf 892# without threads, $filename is not defined until DB::DB is called
2cbb2ee1 893foreach my $k (keys (%INC)) {
fb4d8a6c 894 share(\$main::{'_<'.$filename}) if defined $filename;
2cbb2ee1
RGS
895};
896
54d04a52 897# Command-line + PERLLIB:
69893cff 898# Save the contents of @INC before they are modified elsewhere.
54d04a52
IZ
899@ini_INC = @INC;
900
69893cff
RGS
901# This was an attempt to clear out the previous values of various
902# trapped errors. Apparently it didn't help. XXX More info needed!
d338d6fe
PP
903# $prevwarn = $prevdie = $prevbus = $prevsegv = ''; # Does not help?!
904
69893cff
RGS
905# We set these variables to safe values. We don't want to blindly turn
906# off warnings, because other packages may still want them.
e22ea7cc
RF
907$trace = $signal = $single = 0; # Uninitialized warning suppression
908 # (local $^W cannot help - other packages!).
69893cff
RGS
909
910# Default to not exiting when program finishes; print the return
911# value when the 'r' command is used to return from a subroutine.
55497cff 912$inhibit_exit = $option{PrintRet} = 1;
d338d6fe 913
6b24a4b7
SF
914use vars qw($trace_to_depth);
915
5e2b42dd
SF
916# Default to 1E9 so it won't be limited to a certain recursion depth.
917$trace_to_depth = 1E9;
bdba49ad 918
69893cff
RGS
919=head1 OPTION PROCESSING
920
b570d64b
SF
921The debugger's options are actually spread out over the debugger itself and
922C<dumpvar.pl>; some of these are variables to be set, while others are
69893cff
RGS
923subs to be called with a value. To try to make this a little easier to
924manage, the debugger uses a few data structures to define what options
925are legal and how they are to be processed.
926
927First, the C<@options> array defines the I<names> of all the options that
928are to be accepted.
929
930=cut
931
932@options = qw(
5561b870 933 CommandSet HistFile HistSize
e22ea7cc
RF
934 hashDepth arrayDepth dumpDepth
935 DumpDBFiles DumpPackages DumpReused
936 compactDump veryCompact quote
937 HighBit undefPrint globPrint
938 PrintRet UsageOnly frame
939 AutoTrace TTY noTTY
940 ReadLine NonStop LineInfo
941 maxTraceLen recallCommand ShellBang
942 pager tkRunning ornaments
943 signalLevel warnLevel dieLevel
944 inhibit_exit ImmediateStop bareStringify
945 CreateTTY RemotePort windowSize
584420f0 946 DollarCaretP
e22ea7cc 947);
d12a4851 948
584420f0 949@RememberOnROptions = qw(DollarCaretP);
d12a4851 950
69893cff
RGS
951=pod
952
953Second, C<optionVars> lists the variables that each option uses to save its
954state.
955
956=cut
957
6b24a4b7
SF
958use vars qw(%optionVars);
959
69893cff 960%optionVars = (
e22ea7cc
RF
961 hashDepth => \$dumpvar::hashDepth,
962 arrayDepth => \$dumpvar::arrayDepth,
963 CommandSet => \$CommandSet,
964 DumpDBFiles => \$dumpvar::dumpDBFiles,
965 DumpPackages => \$dumpvar::dumpPackages,
966 DumpReused => \$dumpvar::dumpReused,
967 HighBit => \$dumpvar::quoteHighBit,
968 undefPrint => \$dumpvar::printUndef,
969 globPrint => \$dumpvar::globPrint,
970 UsageOnly => \$dumpvar::usageOnly,
971 CreateTTY => \$CreateTTY,
972 bareStringify => \$dumpvar::bareStringify,
973 frame => \$frame,
974 AutoTrace => \$trace,
975 inhibit_exit => \$inhibit_exit,
976 maxTraceLen => \$maxtrace,
977 ImmediateStop => \$ImmediateStop,
978 RemotePort => \$remoteport,
979 windowSize => \$window,
5561b870
AK
980 HistFile => \$histfile,
981 HistSize => \$histsize,
69893cff
RGS
982);
983
984=pod
985
986Third, C<%optionAction> defines the subroutine to be called to process each
987option.
988
b570d64b 989=cut
69893cff 990
6b24a4b7
SF
991use vars qw(%optionAction);
992
69893cff
RGS
993%optionAction = (
994 compactDump => \&dumpvar::compactDump,
995 veryCompact => \&dumpvar::veryCompact,
996 quote => \&dumpvar::quote,
997 TTY => \&TTY,
998 noTTY => \&noTTY,
999 ReadLine => \&ReadLine,
1000 NonStop => \&NonStop,
1001 LineInfo => \&LineInfo,
1002 recallCommand => \&recallCommand,
1003 ShellBang => \&shellBang,
1004 pager => \&pager,
1005 signalLevel => \&signalLevel,
1006 warnLevel => \&warnLevel,
1007 dieLevel => \&dieLevel,
1008 tkRunning => \&tkRunning,
1009 ornaments => \&ornaments,
1010 RemotePort => \&RemotePort,
1011 DollarCaretP => \&DollarCaretP,
d12a4851
JH
1012);
1013
69893cff
RGS
1014=pod
1015
1016Last, the C<%optionRequire> notes modules that must be C<require>d if an
1017option is used.
1018
1019=cut
d338d6fe 1020
69893cff
RGS
1021# Note that this list is not complete: several options not listed here
1022# actually require that dumpvar.pl be loaded for them to work, but are
1023# not in the table. A subsequent patch will correct this problem; for
1024# the moment, we're just recommenting, and we are NOT going to change
1025# function.
6b24a4b7
SF
1026use vars qw(%optionRequire);
1027
eda6e075 1028%optionRequire = (
69893cff
RGS
1029 compactDump => 'dumpvar.pl',
1030 veryCompact => 'dumpvar.pl',
1031 quote => 'dumpvar.pl',
e22ea7cc 1032);
69893cff
RGS
1033
1034=pod
1035
1036There are a number of initialization-related variables which can be set
1037by putting code to set them in a BEGIN block in the C<PERL5DB> environment
1038variable. These are:
1039
1040=over 4
1041
1042=item C<$rl> - readline control XXX needs more explanation
1043
1044=item C<$warnLevel> - whether or not debugger takes over warning handling
1045
1046=item C<$dieLevel> - whether or not debugger takes over die handling
1047
1048=item C<$signalLevel> - whether or not debugger takes over signal handling
1049
1050=item C<$pre> - preprompt actions (array reference)
1051
1052=item C<$post> - postprompt actions (array reference)
1053
1054=item C<$pretype>
1055
1056=item C<$CreateTTY> - whether or not to create a new TTY for this debugger
1057
1058=item C<$CommandSet> - which command set to use (defaults to new, documented set)
1059
1060=back
1061
1062=cut
d338d6fe
PP
1063
1064# These guys may be defined in $ENV{PERL5DB} :
69893cff
RGS
1065$rl = 1 unless defined $rl;
1066$warnLevel = 1 unless defined $warnLevel;
1067$dieLevel = 1 unless defined $dieLevel;
1068$signalLevel = 1 unless defined $signalLevel;
1069$pre = [] unless defined $pre;
1070$post = [] unless defined $post;
1071$pretype = [] unless defined $pretype;
1072$CreateTTY = 3 unless defined $CreateTTY;
1073$CommandSet = '580' unless defined $CommandSet;
1074
2cbb2ee1
RGS
1075share($rl);
1076share($warnLevel);
1077share($dieLevel);
1078share($signalLevel);
1079share($pre);
1080share($post);
1081share($pretype);
1082share($rl);
1083share($CreateTTY);
1084share($CommandSet);
1085
69893cff
RGS
1086=pod
1087
1088The default C<die>, C<warn>, and C<signal> handlers are set up.
1089
1090=cut
055fd3a9 1091
d338d6fe
PP
1092warnLevel($warnLevel);
1093dieLevel($dieLevel);
1094signalLevel($signalLevel);
055fd3a9 1095
69893cff
RGS
1096=pod
1097
1098The pager to be used is needed next. We try to get it from the
5561b870 1099environment first. If it's not defined there, we try to find it in
69893cff
RGS
1100the Perl C<Config.pm>. If it's not there, we default to C<more>. We
1101then call the C<pager()> function to save the pager name.
1102
1103=cut
1104
1105# This routine makes sure $pager is set up so that '|' can use it.
4865a36d 1106pager(
e22ea7cc 1107
69893cff 1108 # If PAGER is defined in the environment, use it.
e22ea7cc
RF
1109 defined $ENV{PAGER}
1110 ? $ENV{PAGER}
69893cff
RGS
1111
1112 # If not, see if Config.pm defines it.
e22ea7cc
RF
1113 : eval { require Config }
1114 && defined $Config::Config{pager}
1115 ? $Config::Config{pager}
69893cff
RGS
1116
1117 # If not, fall back to 'more'.
e22ea7cc
RF
1118 : 'more'
1119 )
1120 unless defined $pager;
69893cff
RGS
1121
1122=pod
1123
1124We set up the command to be used to access the man pages, the command
be9a9b1d
AT
1125recall character (C<!> unless otherwise defined) and the shell escape
1126character (C<!> unless otherwise defined). Yes, these do conflict, and
69893cff
RGS
1127neither works in the debugger at the moment.
1128
1129=cut
1130
055fd3a9 1131setman();
69893cff
RGS
1132
1133# Set up defaults for command recall and shell escape (note:
1134# these currently don't work in linemode debugging).
2218c045
SF
1135recallCommand("!") unless defined $prc;
1136shellBang("!") unless defined $psh;
69893cff
RGS
1137
1138=pod
1139
1140We then set up the gigantic string containing the debugger help.
1141We also set the limit on the number of arguments we'll display during a
1142trace.
1143
1144=cut
1145
04e43a21 1146sethelp();
69893cff
RGS
1147
1148# If we didn't get a default for the length of eval/stack trace args,
1149# set it here.
1d06cb2d 1150$maxtrace = 400 unless defined $maxtrace;
69893cff
RGS
1151
1152=head2 SETTING UP THE DEBUGGER GREETING
1153
be9a9b1d 1154The debugger I<greeting> helps to inform the user how many debuggers are
69893cff
RGS
1155running, and whether the current debugger is the primary or a child.
1156
1157If we are the primary, we just hang onto our pid so we'll have it when
1158or if we start a child debugger. If we are a child, we'll set things up
1159so we'll have a unique greeting and so the parent will give us our own
1160TTY later.
1161
1162We save the current contents of the C<PERLDB_PIDS> environment variable
1163because we mess around with it. We'll also need to hang onto it because
1164we'll need it if we restart.
1165
1166Child debuggers make a label out of the current PID structure recorded in
1167PERLDB_PIDS plus the new PID. They also mark themselves as not having a TTY
1168yet so the parent will give them one later via C<resetterm()>.
1169
1170=cut
1171
e22ea7cc 1172# Save the current contents of the environment; we're about to
69893cff 1173# much with it. We'll need this if we have to restart.
6b24a4b7 1174use vars qw($ini_pids);
f1583d8f 1175$ini_pids = $ENV{PERLDB_PIDS};
69893cff 1176
6b24a4b7
SF
1177use vars qw ($pids $term_pid);
1178
e22ea7cc
RF
1179if ( defined $ENV{PERLDB_PIDS} ) {
1180
69893cff 1181 # We're a child. Make us a label out of the current PID structure
e22ea7cc 1182 # recorded in PERLDB_PIDS plus our (new) PID. Mark us as not having
69893cff 1183 # a term yet so the parent will give us one later via resetterm().
55f4245e
JM
1184
1185 my $env_pids = $ENV{PERLDB_PIDS};
1186 $pids = "[$env_pids]";
1187
1188 # Unless we are on OpenVMS, all programs under the DCL shell run under
1189 # the same PID.
1190
1191 if (($^O eq 'VMS') && ($env_pids =~ /\b$$\b/)) {
1192 $term_pid = $$;
1193 }
1194 else {
1195 $ENV{PERLDB_PIDS} .= "->$$";
1196 $term_pid = -1;
1197 }
1198
69893cff
RGS
1199} ## end if (defined $ENV{PERLDB_PIDS...
1200else {
e22ea7cc
RF
1201
1202 # We're the parent PID. Initialize PERLDB_PID in case we end up with a
69893cff
RGS
1203 # child debugger, and mark us as the parent, so we'll know to set up
1204 # more TTY's is we have to.
1205 $ENV{PERLDB_PIDS} = "$$";
619a0444 1206 $pids = "[pid=$$]";
e22ea7cc 1207 $term_pid = $$;
f1583d8f 1208}
69893cff 1209
6b24a4b7 1210use vars qw($pidprompt);
f1583d8f 1211$pidprompt = '';
69893cff
RGS
1212
1213# Sets up $emacs as a synonym for $slave_editor.
6b24a4b7 1214use vars qw($slave_editor);
69893cff
RGS
1215*emacs = $slave_editor if $slave_editor; # May be used in afterinit()...
1216
1217=head2 READING THE RC FILE
1218
b570d64b 1219The debugger will read a file of initialization options if supplied. If
69893cff
RGS
1220running interactively, this is C<.perldb>; if not, it's C<perldb.ini>.
1221
b570d64b 1222=cut
69893cff
RGS
1223
1224# As noted, this test really doesn't check accurately that the debugger
1225# is running at a terminal or not.
d338d6fe 1226
6b24a4b7 1227use vars qw($rcfile);
fb4d8a6c
SF
1228{
1229 my $dev_tty = (($^O eq 'VMS') ? 'TT:' : '/dev/tty');
1230 # this is the wrong metric!
1231 $rcfile = ((-e $dev_tty) ? ".perldb" : "perldb.ini");
d338d6fe
PP
1232}
1233
69893cff
RGS
1234=pod
1235
1236The debugger does a safety test of the file to be read. It must be owned
1237either by the current user or root, and must only be writable by the owner.
1238
1239=cut
1240
1241# This wraps a safety test around "do" to read and evaluate the init file.
1242#
055fd3a9
GS
1243# This isn't really safe, because there's a race
1244# between checking and opening. The solution is to
1245# open and fstat the handle, but then you have to read and
1246# eval the contents. But then the silly thing gets
69893cff
RGS
1247# your lexical scope, which is unfortunate at best.
1248sub safe_do {
055fd3a9
GS
1249 my $file = shift;
1250
1251 # Just exactly what part of the word "CORE::" don't you understand?
69893cff
RGS
1252 local $SIG{__WARN__};
1253 local $SIG{__DIE__};
055fd3a9 1254
e22ea7cc 1255 unless ( is_safe_file($file) ) {
69893cff 1256 CORE::warn <<EO_GRIPE;
055fd3a9 1257perldb: Must not source insecure rcfile $file.
b570d64b 1258 You or the superuser must be the owner, and it must not
69893cff 1259 be writable by anyone but its owner.
055fd3a9 1260EO_GRIPE
69893cff
RGS
1261 return;
1262 } ## end unless (is_safe_file($file...
055fd3a9
GS
1263
1264 do $file;
1265 CORE::warn("perldb: couldn't parse $file: $@") if $@;
69893cff 1266} ## end sub safe_do
055fd3a9 1267
69893cff
RGS
1268# This is the safety test itself.
1269#
055fd3a9
GS
1270# Verifies that owner is either real user or superuser and that no
1271# one but owner may write to it. This function is of limited use
1272# when called on a path instead of upon a handle, because there are
1273# no guarantees that filename (by dirent) whose file (by ino) is
e22ea7cc 1274# eventually accessed is the same as the one tested.
055fd3a9
GS
1275# Assumes that the file's existence is not in doubt.
1276sub is_safe_file {
1277 my $path = shift;
69893cff 1278 stat($path) || return; # mysteriously vaporized
e22ea7cc 1279 my ( $dev, $ino, $mode, $nlink, $uid, $gid ) = stat(_);
055fd3a9
GS
1280
1281 return 0 if $uid != 0 && $uid != $<;
1282 return 0 if $mode & 022;
1283 return 1;
69893cff 1284} ## end sub is_safe_file
055fd3a9 1285
69893cff 1286# If the rcfile (whichever one we decided was the right one to read)
e22ea7cc
RF
1287# exists, we safely do it.
1288if ( -f $rcfile ) {
055fd3a9 1289 safe_do("./$rcfile");
69893cff 1290}
e22ea7cc 1291
69893cff 1292# If there isn't one here, try the user's home directory.
e22ea7cc 1293elsif ( defined $ENV{HOME} && -f "$ENV{HOME}/$rcfile" ) {
055fd3a9
GS
1294 safe_do("$ENV{HOME}/$rcfile");
1295}
e22ea7cc 1296
69893cff 1297# Else try the login directory.
e22ea7cc 1298elsif ( defined $ENV{LOGDIR} && -f "$ENV{LOGDIR}/$rcfile" ) {
055fd3a9 1299 safe_do("$ENV{LOGDIR}/$rcfile");
d338d6fe
PP
1300}
1301
69893cff 1302# If the PERLDB_OPTS variable has options in it, parse those out next.
e22ea7cc
RF
1303if ( defined $ENV{PERLDB_OPTS} ) {
1304 parse_options( $ENV{PERLDB_OPTS} );
d338d6fe
PP
1305}
1306
69893cff
RGS
1307=pod
1308
1309The last thing we do during initialization is determine which subroutine is
1310to be used to obtain a new terminal when a new debugger is started. Right now,
b0b54b5e 1311the debugger only handles TCP sockets, X11, OS/2, amd Mac OS X
11653f7f 1312(darwin).
69893cff
RGS
1313
1314=cut
1315
1316# Set up the get_fork_TTY subroutine to be aliased to the proper routine.
1317# Works if you're running an xterm or xterm-like window, or you're on
6fae1ad7
RF
1318# OS/2, or on Mac OS X. This may need some expansion.
1319
1320if (not defined &get_fork_TTY) # only if no routine exists
69893cff 1321{
b570d64b 1322 if ( defined $remoteport ) {
11653f7f
JJ
1323 # Expect an inetd-like server
1324 *get_fork_TTY = \&socket_get_fork_TTY; # to listen to us
1325 }
1326 elsif (defined $ENV{TERM} # If we know what kind
6fae1ad7
RF
1327 # of terminal this is,
1328 and $ENV{TERM} eq 'xterm' # and it's an xterm,
1329 and defined $ENV{DISPLAY} # and what display it's on,
1330 )
1331 {
1332 *get_fork_TTY = \&xterm_get_fork_TTY; # use the xterm version
1333 }
1334 elsif ( $^O eq 'os2' ) { # If this is OS/2,
1335 *get_fork_TTY = \&os2_get_fork_TTY; # use the OS/2 version
1336 }
1337 elsif ( $^O eq 'darwin' # If this is Mac OS X
1338 and defined $ENV{TERM_PROGRAM} # and we're running inside
1339 and $ENV{TERM_PROGRAM}
1340 eq 'Apple_Terminal' # Terminal.app
1341 )
1342 {
1343 *get_fork_TTY = \&macosx_get_fork_TTY; # use the Mac OS X version
1344 }
69893cff 1345} ## end if (not defined &get_fork_TTY...
e22ea7cc 1346
dbb46cec
DQ
1347# untaint $^O, which may have been tainted by the last statement.
1348# see bug [perl #24674]
e22ea7cc
RF
1349$^O =~ m/^(.*)\z/;
1350$^O = $1;
f1583d8f 1351
d12a4851 1352# Here begin the unreadable code. It needs fixing.
055fd3a9 1353
69893cff
RGS
1354=head2 RESTART PROCESSING
1355
1356This section handles the restart command. When the C<R> command is invoked, it
1357tries to capture all of the state it can into environment variables, and
1358then sets C<PERLDB_RESTART>. When we start executing again, we check to see
1359if C<PERLDB_RESTART> is there; if so, we reload all the information that
1360the R command stuffed into the environment variables.
1361
b570d64b 1362 PERLDB_RESTART - flag only, contains no restart data itself.
69893cff
RGS
1363 PERLDB_HIST - command history, if it's available
1364 PERLDB_ON_LOAD - breakpoints set by the rc file
1365 PERLDB_POSTPONE - subs that have been loaded/not executed, and have actions
1366 PERLDB_VISITED - files that had breakpoints
1367 PERLDB_FILE_... - breakpoints for a file
1368 PERLDB_OPT - active options
1369 PERLDB_INC - the original @INC
1370 PERLDB_PRETYPE - preprompt debugger actions
1371 PERLDB_PRE - preprompt Perl code
1372 PERLDB_POST - post-prompt Perl code
1373 PERLDB_TYPEAHEAD - typeahead captured by readline()
1374
1375We chug through all these variables and plug the values saved in them
1376back into the appropriate spots in the debugger.
1377
1378=cut
1379
6b24a4b7
SF
1380use vars qw(@hist @truehist %postponed_file @typeahead);
1381
fb0fb5f4
SF
1382sub _restore_shared_globals_after_restart
1383{
1384 @hist = get_list('PERLDB_HIST');
1385 %break_on_load = get_list("PERLDB_ON_LOAD");
1386 %postponed = get_list("PERLDB_POSTPONE");
1387
1388 share(@hist);
1389 share(@truehist);
1390 share(%break_on_load);
1391 share(%postponed);
1392}
1393
e18a02a6 1394sub _restore_breakpoints_and_actions {
e22ea7cc 1395
e22ea7cc 1396 my @had_breakpoints = get_list("PERLDB_VISITED");
e18a02a6 1397
bdba49ad
SF
1398 for my $file_idx ( 0 .. $#had_breakpoints ) {
1399 my $filename = $had_breakpoints[$file_idx];
1400 my %pf = get_list("PERLDB_FILE_$file_idx");
1401 $postponed_file{ $filename } = \%pf if %pf;
1402 my @lines = sort {$a <=> $b} keys(%pf);
1403 my @enabled_statuses = get_list("PERLDB_FILE_ENABLED_$file_idx");
1404 for my $line_idx (0 .. $#lines) {
1405 _set_breakpoint_enabled_status(
1406 $filename,
1407 $lines[$line_idx],
1408 ($enabled_statuses[$line_idx] ? 1 : ''),
1409 );
1410 }
e22ea7cc 1411 }
69893cff 1412
e18a02a6
SF
1413 return;
1414}
1415
ca50076b
SF
1416sub _restore_options_after_restart
1417{
1418 my %options_map = get_list("PERLDB_OPT");
1419
1420 while ( my ( $opt, $val ) = each %options_map ) {
1421 $val =~ s/[\\\']/\\$1/g;
1422 parse_options("$opt'$val'");
1423 }
1424
1425 return;
1426}
1427
18580168
SF
1428sub _restore_globals_after_restart
1429{
1430 # restore original @INC
1431 @INC = get_list("PERLDB_INC");
1432 @ini_INC = @INC;
1433
1434 # return pre/postprompt actions and typeahead buffer
1435 $pretype = [ get_list("PERLDB_PRETYPE") ];
1436 $pre = [ get_list("PERLDB_PRE") ];
1437 $post = [ get_list("PERLDB_POST") ];
1438 @typeahead = get_list( "PERLDB_TYPEAHEAD", @typeahead );
1439
1440 return;
1441}
1442
fb0fb5f4 1443
e18a02a6
SF
1444if ( exists $ENV{PERLDB_RESTART} ) {
1445
1446 # We're restarting, so we don't need the flag that says to restart anymore.
1447 delete $ENV{PERLDB_RESTART};
1448
1449 # $restart = 1;
fb0fb5f4 1450 _restore_shared_globals_after_restart();
e18a02a6
SF
1451
1452 _restore_breakpoints_and_actions();
1453
69893cff 1454 # restore options
ca50076b 1455 _restore_options_after_restart();
69893cff 1456
18580168 1457 _restore_globals_after_restart();
69893cff
RGS
1458} ## end if (exists $ENV{PERLDB_RESTART...
1459
1460=head2 SETTING UP THE TERMINAL
1461
1462Now, we'll decide how the debugger is going to interact with the user.
1463If there's no TTY, we set the debugger to run non-stop; there's not going
1464to be anyone there to enter commands.
1465
1466=cut
54d04a52 1467
6b24a4b7
SF
1468use vars qw($notty $runnonstop $console $tty $LINEINFO);
1469use vars qw($lineinfo $doccmd);
1470
d338d6fe 1471if ($notty) {
69893cff 1472 $runnonstop = 1;
2cbb2ee1 1473 share($runnonstop);
69893cff 1474}
d12a4851 1475
69893cff
RGS
1476=pod
1477
1478If there is a TTY, we have to determine who it belongs to before we can
1479proceed. If this is a slave editor or graphical debugger (denoted by
1480the first command-line switch being '-emacs'), we shift this off and
1481set C<$rl> to 0 (XXX ostensibly to do straight reads).
1482
1483=cut
1484
1485else {
e22ea7cc 1486
69893cff
RGS
1487 # Is Perl being run from a slave editor or graphical debugger?
1488 # If so, don't use readline, and set $slave_editor = 1.
2b0b9dd1
SF
1489 if ($slave_editor = ( @main::ARGV && ( $main::ARGV[0] eq '-emacs' ) )) {
1490 $rl = 0;
1491 shift(@main::ARGV);
1492 }
e22ea7cc
RF
1493
1494 #require Term::ReadLine;
d12a4851 1495
69893cff
RGS
1496=pod
1497
1498We then determine what the console should be on various systems:
1499
1500=over 4
1501
1502=item * Cygwin - We use C<stdin> instead of a separate device.
1503
1504=cut
1505
e22ea7cc
RF
1506 if ( $^O eq 'cygwin' ) {
1507
69893cff
RGS
1508 # /dev/tty is binary. use stdin for textmode
1509 undef $console;
1510 }
1511
1512=item * Unix - use C</dev/tty>.
1513
1514=cut
1515
e22ea7cc 1516 elsif ( -e "/dev/tty" ) {
69893cff
RGS
1517 $console = "/dev/tty";
1518 }
1519
1520=item * Windows or MSDOS - use C<con>.
1521
1522=cut
1523
e22ea7cc 1524 elsif ( $^O eq 'dos' or -e "con" or $^O eq 'MSWin32' ) {
69893cff
RGS
1525 $console = "con";
1526 }
1527
69893cff
RGS
1528=item * VMS - use C<sys$command>.
1529
1530=cut
1531
1532 else {
e22ea7cc 1533
69893cff
RGS
1534 # everything else is ...
1535 $console = "sys\$command";
d12a4851 1536 }
69893cff
RGS
1537
1538=pod
1539
1540=back
1541
1542Several other systems don't use a specific console. We C<undef $console>
1543for those (Windows using a slave editor/graphical debugger, NetWare, OS/2
1544with a slave editor, Epoc).
1545
1546=cut
d12a4851 1547
e22ea7cc
RF
1548 if ( ( $^O eq 'MSWin32' ) and ( $slave_editor or defined $ENV{EMACS} ) ) {
1549
69893cff 1550 # /dev/tty is binary. use stdin for textmode
e22ea7cc
RF
1551 $console = undef;
1552 }
1553
1554 if ( $^O eq 'NetWare' ) {
d12a4851 1555
69893cff
RGS
1556 # /dev/tty is binary. use stdin for textmode
1557 $console = undef;
1558 }
d12a4851 1559
69893cff
RGS
1560 # In OS/2, we need to use STDIN to get textmode too, even though
1561 # it pretty much looks like Unix otherwise.
e22ea7cc
RF
1562 if ( defined $ENV{OS2_SHELL} and ( $slave_editor or $ENV{WINDOWID} ) )
1563 { # In OS/2
1564 $console = undef;
1565 }
1566
1567 # EPOC also falls into the 'got to use STDIN' camp.
1568 if ( $^O eq 'epoc' ) {
1569 $console = undef;
1570 }
d12a4851 1571
69893cff
RGS
1572=pod
1573
1574If there is a TTY hanging around from a parent, we use that as the console.
1575
1576=cut
1577
e22ea7cc 1578 $console = $tty if defined $tty;
d12a4851 1579
b570d64b 1580=head2 SOCKET HANDLING
69893cff
RGS
1581
1582The debugger is capable of opening a socket and carrying out a debugging
1583session over the socket.
1584
1585If C<RemotePort> was defined in the options, the debugger assumes that it
1586should try to start a debugging session on that port. It builds the socket
1587and then tries to connect the input and output filehandles to it.
1588
1589=cut
1590
1591 # Handle socket stuff.
e22ea7cc
RF
1592
1593 if ( defined $remoteport ) {
1594
69893cff
RGS
1595 # If RemotePort was defined in the options, connect input and output
1596 # to the socket.
11653f7f 1597 $IN = $OUT = connect_remoteport();
69893cff
RGS
1598 } ## end if (defined $remoteport)
1599
1600=pod
1601
1602If no C<RemotePort> was defined, and we want to create a TTY on startup,
1603this is probably a situation where multiple debuggers are running (for example,
1604a backticked command that starts up another debugger). We create a new IN and
1605OUT filehandle, and do the necessary mojo to create a new TTY if we know how
1606and if we can.
1607
1608=cut
1609
1610 # Non-socket.
1611 else {
e22ea7cc 1612
69893cff
RGS
1613 # Two debuggers running (probably a system or a backtick that invokes
1614 # the debugger itself under the running one). create a new IN and OUT
e22ea7cc 1615 # filehandle, and do the necessary mojo to create a new tty if we
69893cff 1616 # know how, and we can.
e22ea7cc
RF
1617 create_IN_OUT(4) if $CreateTTY & 4;
1618 if ($console) {
1619
69893cff 1620 # If we have a console, check to see if there are separate ins and
cd1191f1 1621 # outs to open. (They are assumed identical if not.)
69893cff 1622
e22ea7cc
RF
1623 my ( $i, $o ) = split /,/, $console;
1624 $o = $i unless defined $o;
69893cff 1625
69893cff 1626 # read/write on in, or just read, or read on STDIN.
e22ea7cc
RF
1627 open( IN, "+<$i" )
1628 || open( IN, "<$i" )
1629 || open( IN, "<&STDIN" );
1630
69893cff
RGS
1631 # read/write/create/clobber out, or write/create/clobber out,
1632 # or merge with STDERR, or merge with STDOUT.
e22ea7cc
RF
1633 open( OUT, "+>$o" )
1634 || open( OUT, ">$o" )
1635 || open( OUT, ">&STDERR" )
1636 || open( OUT, ">&STDOUT" ); # so we don't dongle stdout
1637
1638 } ## end if ($console)
1639 elsif ( not defined $console ) {
1640
1641 # No console. Open STDIN.
1642 open( IN, "<&STDIN" );
1643
1644 # merge with STDERR, or with STDOUT.
1645 open( OUT, ">&STDERR" )
1646 || open( OUT, ">&STDOUT" ); # so we don't dongle stdout
1647 $console = 'STDIN/OUT';
69893cff
RGS
1648 } ## end elsif (not defined $console)
1649
1650 # Keep copies of the filehandles so that when the pager runs, it
1651 # can close standard input without clobbering ours.
2b0b9dd1
SF
1652 if ($console or (not defined($console))) {
1653 $IN = \*IN;
1654 $OUT = \*OUT;
1655 }
e22ea7cc
RF
1656 } ## end elsif (from if(defined $remoteport))
1657
1658 # Unbuffer DB::OUT. We need to see responses right away.
70c9432b 1659 $OUT->autoflush(1);
e22ea7cc
RF
1660
1661 # Line info goes to debugger output unless pointed elsewhere.
1662 # Pointing elsewhere makes it possible for slave editors to
1663 # keep track of file and position. We have both a filehandle
1664 # and a I/O description to keep track of.
1665 $LINEINFO = $OUT unless defined $LINEINFO;
1666 $lineinfo = $console unless defined $lineinfo;
2cbb2ee1 1667 # share($LINEINFO); # <- unable to share globs
b570d64b 1668 share($lineinfo); #
e22ea7cc 1669
69893cff
RGS
1670=pod
1671
1672To finish initialization, we show the debugger greeting,
1673and then call the C<afterinit()> subroutine if there is one.
1674
1675=cut
d12a4851 1676
e22ea7cc
RF
1677 # Show the debugger greeting.
1678 $header =~ s/.Header: ([^,]+),v(\s+\S+\s+\S+).*$/$1$2/;
1679 unless ($runnonstop) {
1680 local $\ = '';
1681 local $, = '';
1682 if ( $term_pid eq '-1' ) {
1683 print $OUT "\nDaughter DB session started...\n";
1684 }
1685 else {
1686 print $OUT "\nLoading DB routines from $header\n";
1687 print $OUT (
1688 "Editor support ",
1689 $slave_editor ? "enabled" : "available", ".\n"
1690 );
1691 print $OUT
1f874cb6 1692"\nEnter h or 'h h' for help, or '$doccmd perldebug' for more help.\n\n";
69893cff
RGS
1693 } ## end else [ if ($term_pid eq '-1')
1694 } ## end unless ($runnonstop)
1695} ## end else [ if ($notty)
1696
1697# XXX This looks like a bug to me.
1698# Why copy to @ARGS and then futz with @args?
d338d6fe 1699@ARGS = @ARGV;
6b24a4b7 1700# for (@args) {
69893cff
RGS
1701 # Make sure backslashes before single quotes are stripped out, and
1702 # keep args unless they are numeric (XXX why?)
e22ea7cc
RF
1703 # s/\'/\\\'/g; # removed while not justified understandably
1704 # s/(.*)/'$1'/ unless /^-?[\d.]+$/; # ditto
6b24a4b7 1705# }
d338d6fe 1706
e22ea7cc 1707# If there was an afterinit() sub defined, call it. It will get
69893cff 1708# executed in our scope, so it can fiddle with debugger globals.
e22ea7cc 1709if ( defined &afterinit ) { # May be defined in $rcfile
2b0b9dd1 1710 afterinit();
d338d6fe 1711}
e22ea7cc 1712
69893cff 1713# Inform us about "Stack dump during die enabled ..." in dieLevel().
6b24a4b7
SF
1714use vars qw($I_m_init);
1715
43aed9ee
IZ
1716$I_m_init = 1;
1717
d338d6fe
PP
1718############################################################ Subroutines
1719
69893cff
RGS
1720=head1 SUBROUTINES
1721
1722=head2 DB
1723
1724This gigantic subroutine is the heart of the debugger. Called before every
1725statement, its job is to determine if a breakpoint has been reached, and
1726stop if so; read commands from the user, parse them, and execute
b468dcb6 1727them, and then send execution off to the next statement.
69893cff
RGS
1728
1729Note that the order in which the commands are processed is very important;
1730some commands earlier in the loop will actually alter the C<$cmd> variable
be9a9b1d 1731to create other commands to be executed later. This is all highly I<optimized>
69893cff
RGS
1732but can be confusing. Check the comments for each C<$cmd ... && do {}> to
1733see what's happening in any given command.
1734
1735=cut
1736
6b24a4b7
SF
1737use vars qw(
1738 $action
1739 %alias
1740 $cmd
1741 $doret
1742 $fall_off_end
1743 $file
1744 $filename_ini
1745 $finished
1746 %had_breakpoints
1747 $incr
1748 $laststep
1749 $level
1750 $max
1751 @old_watch
1752 $package
1753 $rc
1754 $sh
1755 @stack
1756 $stack_depth
1757 @to_watch
1758 $try
2c247e84 1759 $end
6b24a4b7
SF
1760);
1761
2b0b9dd1
SF
1762sub _DB_on_init__initialize_globals
1763{
69893cff 1764 # Check for whether we should be running continuously or not.
36477c24 1765 # _After_ the perl program is compiled, $single is set to 1:
e22ea7cc
RF
1766 if ( $single and not $second_time++ ) {
1767
69893cff 1768 # Options say run non-stop. Run until we get an interrupt.
e22ea7cc
RF
1769 if ($runnonstop) { # Disable until signal
1770 # If there's any call stack in place, turn off single
1771 # stepping into subs throughout the stack.
2c247e84 1772 for my $i (0 .. $stack_depth) {
72d7d80d 1773 $stack[ $i ] &= ~1;
e22ea7cc
RF
1774 }
1775
69893cff 1776 # And we are now no longer in single-step mode.
e22ea7cc 1777 $single = 0;
69893cff
RGS
1778
1779 # If we simply returned at this point, we wouldn't get
1780 # the trace info. Fall on through.
e22ea7cc 1781 # return;
69893cff
RGS
1782 } ## end if ($runnonstop)
1783
e22ea7cc
RF
1784 elsif ($ImmediateStop) {
1785
1786 # We are supposed to stop here; XXX probably a break.
1787 $ImmediateStop = 0; # We've processed it; turn it off
1788 $signal = 1; # Simulate an interrupt to force
1789 # us into the command loop
69893cff
RGS
1790 }
1791 } ## end if ($single and not $second_time...
1792
1793 # If we're in single-step mode, or an interrupt (real or fake)
1794 # has occurred, turn off non-stop mode.
1795 $runnonstop = 0 if $single or $signal;
1796
2b0b9dd1
SF
1797 return;
1798}
1799
1800sub DB {
1801
1802 # lock the debugger and get the thread id for the prompt
1803 lock($DBGR);
1804 my $tid;
1805 my $position;
1806 my ($prefix, $after, $infix);
1807 my $pat;
1808
1809 if ($ENV{PERL5DB_THREADED}) {
1810 $tid = eval { "[".threads->tid."]" };
1811 }
1812
1813 _DB_on_init__initialize_globals();
1814
69893cff
RGS
1815 # Preserve current values of $@, $!, $^E, $,, $/, $\, $^W.
1816 # The code being debugged may have altered them.
d338d6fe 1817 &save;
69893cff
RGS
1818
1819 # Since DB::DB gets called after every line, we can use caller() to
1820 # figure out where we last were executing. Sneaky, eh? This works because
e22ea7cc 1821 # caller is returning all the extra information when called from the
69893cff 1822 # debugger.
e22ea7cc 1823 local ( $package, $filename, $line ) = caller;
6b24a4b7 1824 $filename_ini = $filename;
69893cff
RGS
1825
1826 # set up the context for DB::eval, so it can properly execute
1827 # code on behalf of the user. We add the package in so that the
1828 # code is eval'ed in the proper package (not in the debugger!).
6b24a4b7 1829 local $usercontext = _calc_usercontext($package);
69893cff
RGS
1830
1831 # Create an alias to the active file magical array to simplify
1832 # the code here.
e22ea7cc 1833 local (*dbline) = $main::{ '_<' . $filename };
aa057b67 1834
69893cff 1835 # Last line in the program.
55783941 1836 $max = $#dbline;
69893cff
RGS
1837
1838 # if we have something here, see if we should break.
e22ea7cc 1839 {
72d7d80d
SF
1840 # $stop is lexical and local to this block - $action on the other hand
1841 # is global.
1842 my $stop;
e22ea7cc 1843
72d7d80d
SF
1844 if ( $dbline{$line}
1845 && _is_breakpoint_enabled($filename, $line)
1846 && (( $stop, $action ) = split( /\0/, $dbline{$line} ) ) )
1847 {
e22ea7cc 1848
72d7d80d
SF
1849 # Stop if the stop criterion says to just stop.
1850 if ( $stop eq '1' ) {
1851 $signal |= 1;
5d5d9ea3 1852 }
72d7d80d
SF
1853
1854 # It's a conditional stop; eval it in the user's context and
1855 # see if we should stop. If so, remove the one-time sigil.
1856 elsif ($stop) {
1857 $evalarg = "\$DB::signal |= 1 if do {$stop}";
1858 &eval;
1859 # If the breakpoint is temporary, then delete its enabled status.
1860 if ($dbline{$line} =~ s/;9($|\0)/$1/) {
1861 _cancel_breakpoint_temp_enabled_status($filename, $line);
1862 }
1863 }
1864 } ## end if ($dbline{$line} && ...
1865 }
69893cff
RGS
1866
1867 # Preserve the current stop-or-not, and see if any of the W
1868 # (watch expressions) has changed.
36477c24 1869 my $was_signal = $signal;
69893cff
RGS
1870
1871 # If we have any watch expressions ...
e22ea7cc 1872 if ( $trace & 2 ) {
2c247e84 1873 for my $n (0 .. $#to_watch) {
e22ea7cc
RF
1874 $evalarg = $to_watch[$n];
1875 local $onetimeDump; # Tell DB::eval() to not output results
69893cff
RGS
1876
1877 # Fix context DB::eval() wants to return an array, but
1878 # we need a scalar here.
e22ea7cc
RF
1879 my ($val) = join( "', '", &eval );
1880 $val = ( ( defined $val ) ? "'$val'" : 'undef' );
69893cff
RGS
1881
1882 # Did it change?
e22ea7cc
RF
1883 if ( $val ne $old_watch[$n] ) {
1884
69893cff 1885 # Yep! Show the difference, and fake an interrupt.
e22ea7cc
RF
1886 $signal = 1;
1887 print $OUT <<EOP;
405ff068 1888Watchpoint $n:\t$to_watch[$n] changed:
69893cff
RGS
1889 old value:\t$old_watch[$n]
1890 new value:\t$val
6027b9a3 1891EOP
e22ea7cc 1892 $old_watch[$n] = $val;
69893cff 1893 } ## end if ($val ne $old_watch...
2c247e84 1894 } ## end for my $n (0 ..
69893cff
RGS
1895 } ## end if ($trace & 2)
1896
1897=head2 C<watchfunction()>
1898
1899C<watchfunction()> is a function that can be defined by the user; it is a
b570d64b 1900function which will be run on each entry to C<DB::DB>; it gets the
69893cff
RGS
1901current package, filename, and line as its parameters.
1902
b570d64b 1903The watchfunction can do anything it likes; it is executing in the
69893cff
RGS
1904debugger's context, so it has access to all of the debugger's internal
1905data structures and functions.
1906
1907C<watchfunction()> can control the debugger's actions. Any of the following
1908will cause the debugger to return control to the user's program after
1909C<watchfunction()> executes:
1910
b570d64b 1911=over 4
69893cff 1912
be9a9b1d
AT
1913=item *
1914
1915Returning a false value from the C<watchfunction()> itself.
1916
1917=item *
1918
1919Altering C<$single> to a false value.
1920
1921=item *
69893cff 1922
be9a9b1d 1923Altering C<$signal> to a false value.
69893cff 1924
be9a9b1d 1925=item *
69893cff 1926
be9a9b1d 1927Turning off the C<4> bit in C<$trace> (this also disables the
69893cff
RGS
1928check for C<watchfunction()>. This can be done with
1929
1930 $trace &= ~4;
1931
1932=back
1933
1934=cut
1935
e22ea7cc 1936 # If there's a user-defined DB::watchfunction, call it with the
69893cff
RGS
1937 # current package, filename, and line. The function executes in
1938 # the DB:: package.
e22ea7cc
RF
1939 if ( $trace & 4 ) { # User-installed watch
1940 return
1941 if watchfunction( $package, $filename, $line )
1942 and not $single
1943 and not $was_signal
1944 and not( $trace & ~4 );
69893cff
RGS
1945 } ## end if ($trace & 4)
1946
e22ea7cc 1947 # Pick up any alteration to $signal in the watchfunction, and
69893cff 1948 # turn off the signal now.
6027b9a3 1949 $was_signal = $signal;
69893cff
RGS
1950 $signal = 0;
1951
1952=head2 GETTING READY TO EXECUTE COMMANDS
1953
1954The debugger decides to take control if single-step mode is on, the
1955C<t> command was entered, or the user generated a signal. If the program
1956has fallen off the end, we set things up so that entering further commands
1957won't cause trouble, and we say that the program is over.
1958
1959=cut
1960
8dc67a69
SF
1961 # Make sure that we always print if asked for explicitly regardless
1962 # of $trace_to_depth .
1963 my $explicit_stop = ($single || $was_signal);
1964
69893cff
RGS
1965 # Check to see if we should grab control ($single true,
1966 # trace set appropriately, or we got a signal).
8dc67a69 1967 if ( $explicit_stop || ( $trace & 1 ) ) {
e22ea7cc 1968
69893cff 1969 # Yes, grab control.
e22ea7cc
RF
1970 if ($slave_editor) {
1971
69893cff 1972 # Tell the editor to update its position.
e22ea7cc
RF
1973 $position = "\032\032$filename:$line:0\n";
1974 print_lineinfo($position);
1975 }
69893cff
RGS
1976
1977=pod
1978
b570d64b 1979Special check: if we're in package C<DB::fake>, we've gone through the
69893cff
RGS
1980C<END> block at least once. We set up everything so that we can continue
1981to enter commands and have a valid context to be in.
1982
1983=cut
1984
e22ea7cc 1985 elsif ( $package eq 'DB::fake' ) {
69893cff 1986
69893cff 1987 # Fallen off the end already.
e22ea7cc
RF
1988 $term || &setterm;
1989 print_help(<<EOP);
405ff068 1990Debugged program terminated. Use B<q> to quit or B<R> to restart,
6b27b0a0 1991 use B<o> I<inhibit_exit> to avoid stopping after program termination,
b570d64b 1992 B<h q>, B<h R> or B<h o> to get additional info.
405ff068 1993EOP
e22ea7cc 1994
69893cff 1995 # Set the DB::eval context appropriately.
e22ea7cc 1996 $package = 'main';
6b24a4b7 1997 $usercontext = _calc_usercontext($package);
69893cff 1998 } ## end elsif ($package eq 'DB::fake')
e219e2fb 1999
69893cff 2000=pod
e219e2fb 2001
69893cff
RGS
2002If the program hasn't finished executing, we scan forward to the
2003next executable line, print that out, build the prompt from the file and line
b570d64b 2004number information, and print that.
e219e2fb 2005
69893cff
RGS
2006=cut
2007
e22ea7cc
RF
2008 else {
2009
8dc67a69 2010
69893cff
RGS
2011 # Still somewhere in the midst of execution. Set up the
2012 # debugger prompt.
2013 $sub =~ s/\'/::/; # Swap Perl 4 package separators (') to
e22ea7cc 2014 # Perl 5 ones (sorry, we don't print Klingon
69893cff
RGS
2015 #module names)
2016
6b24a4b7 2017 $prefix = $sub =~ /::/ ? "" : ($package . '::');
e22ea7cc
RF
2018 $prefix .= "$sub($filename:";
2019 $after = ( $dbline[$line] =~ /\n$/ ? '' : "\n" );
69893cff
RGS
2020
2021 # Break up the prompt if it's really long.
e22ea7cc
RF
2022 if ( length($prefix) > 30 ) {
2023 $position = "$prefix$line):\n$line:\t$dbline[$line]$after";
2024 $prefix = "";
2025 $infix = ":\t";
2026 }
2027 else {
2028 $infix = "):\t";
2029 $position = "$prefix$line$infix$dbline[$line]$after";
2030 }
69893cff
RGS
2031
2032 # Print current line info, indenting if necessary.
e22ea7cc
RF
2033 if ($frame) {
2034 print_lineinfo( ' ' x $stack_depth,
2035 "$line:\t$dbline[$line]$after" );
2036 }
2037 else {
8dc67a69 2038 depth_print_lineinfo($explicit_stop, $position);
e22ea7cc 2039 }
69893cff
RGS
2040
2041 # Scan forward, stopping at either the end or the next
2042 # unbreakable line.
72d7d80d 2043 for ( my $i = $line + 1 ; $i <= $max && $dbline[$i] == 0 ; ++$i )
e22ea7cc 2044 { #{ vi
69893cff
RGS
2045
2046 # Drop out on null statements, block closers, and comments.
2047 last if $dbline[$i] =~ /^\s*[\;\}\#\n]/;
2048
2049 # Drop out if the user interrupted us.
2050 last if $signal;
2051
2052 # Append a newline if the line doesn't have one. Can happen
2053 # in eval'ed text, for instance.
e22ea7cc 2054 $after = ( $dbline[$i] =~ /\n$/ ? '' : "\n" );
69893cff
RGS
2055
2056 # Next executable line.
6b24a4b7 2057 my $incr_pos = "$prefix$i$infix$dbline[$i]$after";
69893cff
RGS
2058 $position .= $incr_pos;
2059 if ($frame) {
e22ea7cc 2060
69893cff 2061 # Print it indented if tracing is on.
e22ea7cc
RF
2062 print_lineinfo( ' ' x $stack_depth,
2063 "$i:\t$dbline[$i]$after" );
69893cff
RGS
2064 }
2065 else {
8dc67a69 2066 depth_print_lineinfo($explicit_stop, $incr_pos);
69893cff 2067 }
72d7d80d 2068 } ## end for ($i = $line + 1 ; $i...
69893cff
RGS
2069 } ## end else [ if ($slave_editor)
2070 } ## end if ($single || ($trace...
2071
2072=pod
2073
2074If there's an action to be executed for the line we stopped at, execute it.
b570d64b 2075If there are any preprompt actions, execute those as well.
e219e2fb
RF
2076
2077=cut
2078
69893cff
RGS
2079 # If there's an action, do it now.
2080 $evalarg = $action, &eval if $action;
e219e2fb 2081
69893cff
RGS
2082 # Are we nested another level (e.g., did we evaluate a function
2083 # that had a breakpoint in it at the debugger prompt)?
e22ea7cc
RF
2084 if ( $single || $was_signal ) {
2085
69893cff 2086 # Yes, go down a level.
e22ea7cc 2087 local $level = $level + 1;
69893cff
RGS
2088
2089 # Do any pre-prompt actions.
e22ea7cc
RF
2090 foreach $evalarg (@$pre) {
2091 &eval;
2092 }
69893cff
RGS
2093
2094 # Complain about too much recursion if we passed the limit.
e22ea7cc 2095 print $OUT $stack_depth . " levels deep in subroutine calls!\n"
69893cff
RGS
2096 if $single & 4;
2097
2098 # The line we're currently on. Set $incr to -1 to stay here
2099 # until we get a command that tells us to advance.
e22ea7cc
RF
2100 $start = $line;
2101 $incr = -1; # for backward motion.
69893cff
RGS
2102
2103 # Tack preprompt debugger actions ahead of any actual input.
e22ea7cc 2104 @typeahead = ( @$pretype, @typeahead );
69893cff
RGS
2105
2106=head2 WHERE ARE WE?
2107
2108XXX Relocate this section?
2109
2110The debugger normally shows the line corresponding to the current line of
2111execution. Sometimes, though, we want to see the next line, or to move elsewhere
2112in the file. This is done via the C<$incr>, C<$start>, and C<$max> variables.
2113
be9a9b1d
AT
2114C<$incr> controls by how many lines the I<current> line should move forward
2115after a command is executed. If set to -1, this indicates that the I<current>
69893cff
RGS
2116line shouldn't change.
2117
be9a9b1d 2118C<$start> is the I<current> line. It is used for things like knowing where to
69893cff
RGS
2119move forwards or backwards from when doing an C<L> or C<-> command.
2120
2121C<$max> tells the debugger where the last line of the current file is. It's
2122used to terminate loops most often.
2123
2124=head2 THE COMMAND LOOP
2125
2126Most of C<DB::DB> is actually a command parsing and dispatch loop. It comes
2127in two parts:
2128
2129=over 4
2130
be9a9b1d
AT
2131=item *
2132
2133The outer part of the loop, starting at the C<CMD> label. This loop
69893cff
RGS
2134reads a command and then executes it.
2135
be9a9b1d
AT
2136=item *
2137
2138The inner part of the loop, starting at the C<PIPE> label. This part
69893cff
RGS
2139is wholly contained inside the C<CMD> block and only executes a command.
2140Used to handle commands running inside a pager.
2141
2142=back
2143
2144So why have two labels to restart the loop? Because sometimes, it's easier to
2145have a command I<generate> another command and then re-execute the loop to do
2146the new command. This is faster, but perhaps a bit more convoluted.
2147
2148=cut
2149
2150 # The big command dispatch loop. It keeps running until the
2151 # user yields up control again.
2152 #
2153 # If we have a terminal for input, and we get something back
2154 # from readline(), keep on processing.
6b24a4b7
SF
2155 my $piped;
2156 my $selected;
2157
e22ea7cc
RF
2158 CMD:
2159 while (
2160
69893cff 2161 # We have a terminal, or can get one ...
e22ea7cc
RF
2162 ( $term || &setterm ),
2163
69893cff 2164 # ... and it belogs to this PID or we get one for this PID ...
e22ea7cc
RF
2165 ( $term_pid == $$ or resetterm(1) ),
2166
69893cff 2167 # ... and we got a line of command input ...
e22ea7cc
RF
2168 defined(
2169 $cmd = &readline(
2cbb2ee1 2170 "$pidprompt $tid DB"
e22ea7cc
RF
2171 . ( '<' x $level )
2172 . ( $#hist + 1 )
2173 . ( '>' x $level ) . " "
69893cff
RGS
2174 )
2175 )
2176 )
2177 {
e22ea7cc 2178
2cbb2ee1 2179 share($cmd);
69893cff
RGS
2180 # ... try to execute the input as debugger commands.
2181
2182 # Don't stop running.
2183 $single = 0;
2184
2185 # No signal is active.
2186 $signal = 0;
2187
2188 # Handle continued commands (ending with \):
3d7a2a93 2189 if ($cmd =~ s/\\\z/\n/) {
e22ea7cc
RF
2190 $cmd .= &readline(" cont: ");
2191 redo CMD;
3d7a2a93 2192 }
69893cff
RGS
2193
2194=head4 The null command
2195
be9a9b1d 2196A newline entered by itself means I<re-execute the last command>. We grab the
69893cff
RGS
2197command out of C<$laststep> (where it was recorded previously), and copy it
2198back into C<$cmd> to be executed below. If there wasn't any previous command,
2199we'll do nothing below (no command will match). If there was, we also save it
2200in the command history and fall through to allow the command parsing to pick
2201it up.
2202
2203=cut
2204
2205 # Empty input means repeat the last command.
e22ea7cc
RF
2206 $cmd =~ /^$/ && ( $cmd = $laststep );
2207 chomp($cmd); # get rid of the annoying extra newline
2208 push( @hist, $cmd ) if length($cmd) > 1;
2209 push( @truehist, $cmd );
2cbb2ee1
RGS
2210 share(@hist);
2211 share(@truehist);
e22ea7cc
RF
2212
2213 # This is a restart point for commands that didn't arrive
2214 # via direct user input. It allows us to 'redo PIPE' to
2215 # re-execute command processing without reading a new command.
69893cff 2216 PIPE: {
e22ea7cc
RF
2217 $cmd =~ s/^\s+//s; # trim annoying leading whitespace
2218 $cmd =~ s/\s+$//s; # trim annoying trailing whitespace
6b24a4b7 2219 my ($i) = split( /\s+/, $cmd );
69893cff
RGS
2220
2221=head3 COMMAND ALIASES
2222
2223The debugger can create aliases for commands (these are stored in the
2224C<%alias> hash). Before a command is executed, the command loop looks it up
2225in the alias hash and substitutes the contents of the alias for the command,
2226completely replacing it.
2227
2228=cut
2229
2230 # See if there's an alias for the command, and set it up if so.
e22ea7cc
RF
2231 if ( $alias{$i} ) {
2232
69893cff
RGS
2233 # Squelch signal handling; we want to keep control here
2234 # if something goes loco during the alias eval.
2235 local $SIG{__DIE__};
2236 local $SIG{__WARN__};
2237
2238 # This is a command, so we eval it in the DEBUGGER's
2239 # scope! Otherwise, we can't see the special debugger
2240 # variables, or get to the debugger's subs. (Well, we
2241 # _could_, but why make it even more complicated?)
2242 eval "\$cmd =~ $alias{$i}";
2243 if ($@) {
2244 local $\ = '';
1f874cb6 2245 print $OUT "Couldn't evaluate '$i' alias: $@";
69893cff
RGS
2246 next CMD;
2247 }
2248 } ## end if ($alias{$i})
2249
2250=head3 MAIN-LINE COMMANDS
2251
2252All of these commands work up to and after the program being debugged has
b570d64b 2253terminated.
69893cff
RGS
2254
2255=head4 C<q> - quit
2256
b570d64b 2257Quit the debugger. This entails setting the C<$fall_off_end> flag, so we don't
69893cff
RGS
2258try to execute further, cleaning any restart-related stuff out of the
2259environment, and executing with the last value of C<$?>.
2260
2261=cut
2262
3d7a2a93 2263 if ($cmd eq 'q') {
69893cff
RGS
2264 $fall_off_end = 1;
2265 clean_ENV();
2266 exit $?;
3d7a2a93 2267 }
69893cff 2268
611272bb 2269=head4 C<t> - trace [n]
69893cff
RGS
2270
2271Turn tracing on or off. Inverts the appropriate bit in C<$trace> (q.v.).
611272bb 2272If level is specified, set C<$trace_to_depth>.
69893cff
RGS
2273
2274=cut
2275
3d7a2a93 2276 if (my ($levels) = $cmd =~ /\At(?:\s+(\d+))?\z/) {
e22ea7cc
RF
2277 $trace ^= 1;
2278 local $\ = '';
611272bb 2279 $trace_to_depth = $levels ? $stack_depth + $levels : 1E9;
e22ea7cc 2280 print $OUT "Trace = "
611272bb
PS
2281 . ( ( $trace & 1 )
2282 ? ( $levels ? "on (to level $trace_to_depth)" : "on" )
2283 : "off" ) . "\n";
e22ea7cc 2284 next CMD;
3d7a2a93 2285 }
69893cff
RGS
2286
2287=head4 C<S> - list subroutines matching/not matching a pattern
2288
2289Walks through C<%sub>, checking to see whether or not to print the name.
2290
2291=cut
2292
826b9a2e
SF
2293 if (my ($print_all_subs, $should_reverse, $Spatt)
2294 = $cmd =~ /\AS(\s+(!)?(.+))?\z/) {
2295 # $Spatt is the pattern (if any) to use.
2296 # Reverse scan?
2297 my $Srev = defined $should_reverse;
2298 # No args - print all subs.
2299 my $Snocheck = !defined $print_all_subs;
69893cff
RGS
2300
2301 # Need to make these sane here.
e22ea7cc
RF
2302 local $\ = '';
2303 local $, = '';
69893cff
RGS
2304
2305 # Search through the debugger's magical hash of subs.
2306 # If $nocheck is true, just print the sub name.
2307 # Otherwise, check it against the pattern. We then use
2308 # the XOR trick to reverse the condition as required.
e22ea7cc
RF
2309 foreach $subname ( sort( keys %sub ) ) {
2310 if ( $Snocheck or $Srev ^ ( $subname =~ /$Spatt/ ) ) {
2311 print $OUT $subname, "\n";
2312 }
2313 }
2314 next CMD;
826b9a2e 2315 }
69893cff
RGS
2316
2317=head4 C<X> - list variables in current package
2318
b570d64b 2319Since the C<V> command actually processes this, just change this to the
69893cff
RGS
2320appropriate C<V> command and fall through.
2321
2322=cut
2323
e22ea7cc 2324 $cmd =~ s/^X\b/V $package/;
69893cff
RGS
2325
2326=head4 C<V> - list variables
2327
b570d64b 2328Uses C<dumpvar.pl> to dump out the current values for selected variables.
69893cff
RGS
2329
2330=cut
2331
2332 # Bare V commands get the currently-being-debugged package
2333 # added.
826b9a2e 2334 if ($cmd eq "V") {
e22ea7cc 2335 $cmd = "V $package";
826b9a2e 2336 }
69893cff
RGS
2337
2338 # V - show variables in package.
826b9a2e
SF
2339 if (my ($new_packname, $new_vars_str) =
2340 $cmd =~ /\AV\b\s*(\S+)\s*(.*)/) {
e22ea7cc 2341
69893cff
RGS
2342 # Save the currently selected filehandle and
2343 # force output to debugger's filehandle (dumpvar
2344 # just does "print" for output).
6b24a4b7 2345 my $savout = select($OUT);
69893cff
RGS
2346
2347 # Grab package name and variables to dump.
826b9a2e
SF
2348 $packname = $new_packname;
2349 my @vars = split( ' ', $new_vars_str );
69893cff
RGS
2350
2351 # If main::dumpvar isn't here, get it.
e81465be 2352 do 'dumpvar.pl' || die $@ unless defined &main::dumpvar;
e22ea7cc
RF
2353 if ( defined &main::dumpvar ) {
2354
69893cff
RGS
2355 # We got it. Turn off subroutine entry/exit messages
2356 # for the moment, along with return values.
e22ea7cc
RF
2357 local $frame = 0;
2358 local $doret = -2;
69893cff
RGS
2359
2360 # must detect sigpipe failures - not catching
2361 # then will cause the debugger to die.
2362 eval {
2363 &main::dumpvar(
2364 $packname,
2365 defined $option{dumpDepth}
e22ea7cc
RF
2366 ? $option{dumpDepth}
2367 : -1, # assume -1 unless specified
69893cff 2368 @vars
e22ea7cc
RF
2369 );
2370 };
2371
2372 # The die doesn't need to include the $@, because
2373 # it will automatically get propagated for us.
2374 if ($@) {
2375 die unless $@ =~ /dumpvar print failed/;
2376 }
2377 } ## end if (defined &main::dumpvar)
2378 else {
2379
2380 # Couldn't load dumpvar.
2381 print $OUT "dumpvar.pl not available.\n";
2382 }
69893cff 2383
69893cff 2384 # Restore the output filehandle, and go round again.
e22ea7cc
RF
2385 select($savout);
2386 next CMD;
826b9a2e 2387 }
69893cff
RGS
2388
2389=head4 C<x> - evaluate and print an expression
2390
2391Hands the expression off to C<DB::eval>, setting it up to print the value
2392via C<dumpvar.pl> instead of just printing it directly.
2393
2394=cut
2395
826b9a2e 2396 if ($cmd =~ s#\Ax\b# #) { # Remainder gets done by DB::eval()
e22ea7cc 2397 $onetimeDump = 'dump'; # main::dumpvar shows the output
69893cff
RGS
2398
2399 # handle special "x 3 blah" syntax XXX propagate
2400 # doc back to special variables.
826b9a2e 2401 if ( $cmd =~ s#\A\s*(\d+)(?=\s)# #) {
e22ea7cc
RF
2402 $onetimedumpDepth = $1;
2403 }
826b9a2e 2404 }
69893cff
RGS
2405
2406=head4 C<m> - print methods
2407
2408Just uses C<DB::methods> to determine what methods are available.
2409
2410=cut
2411
826b9a2e 2412 if ($cmd =~ s#\Am\s+([\w:]+)\s*\z# #) {
e22ea7cc
RF
2413 methods($1);
2414 next CMD;
826b9a2e 2415 }
69893cff
RGS
2416
2417 # m expr - set up DB::eval to do the work
826b9a2e 2418 if ($cmd =~ s#\Am\b# #) { # Rest gets done by DB::eval()
e22ea7cc 2419 $onetimeDump = 'methods'; # method output gets used there
826b9a2e 2420 }
69893cff
RGS
2421
2422=head4 C<f> - switch files
2423
2424=cut
2425
826b9a2e 2426 if (($file) = $cmd =~ /\Af\b\s*(.*)/) {
e22ea7cc 2427 $file =~ s/\s+$//;
69893cff
RGS
2428
2429 # help for no arguments (old-style was return from sub).
e22ea7cc
RF
2430 if ( !$file ) {
2431 print $OUT
2432 "The old f command is now the r command.\n"; # hint
2433 print $OUT "The new f command switches filenames.\n";
2434 next CMD;
2435 } ## end if (!$file)
69893cff
RGS
2436
2437 # if not in magic file list, try a close match.
e22ea7cc
RF
2438 if ( !defined $main::{ '_<' . $file } ) {
2439 if ( ($try) = grep( m#^_<.*$file#, keys %main:: ) ) {
2440 {
2441 $try = substr( $try, 2 );
1f874cb6 2442 print $OUT "Choosing $try matching '$file':\n";
e22ea7cc
RF
2443 $file = $try;
2444 }
2445 } ## end if (($try) = grep(m#^_<.*$file#...
2446 } ## end if (!defined $main::{ ...
69893cff
RGS
2447
2448 # If not successfully switched now, we failed.
e22ea7cc 2449 if ( !defined $main::{ '_<' . $file } ) {
1f874cb6 2450 print $OUT "No file matching '$file' is loaded.\n";
e22ea7cc
RF
2451 next CMD;
2452 }
69893cff 2453
e22ea7cc
RF
2454 # We switched, so switch the debugger internals around.
2455 elsif ( $file ne $filename ) {
2456 *dbline = $main::{ '_<' . $file };
2457 $max = $#dbline;
2458 $filename = $file;
2459 $start = 1;
2460 $cmd = "l";
2461 } ## end elsif ($file ne $filename)
2462
2463 # We didn't switch; say we didn't.
2464 else {
2465 print $OUT "Already in $file.\n";
2466 next CMD;
2467 }
826b9a2e 2468 }
69893cff
RGS
2469
2470=head4 C<.> - return to last-executed line.
2471
2472We set C<$incr> to -1 to indicate that the debugger shouldn't move ahead,
2473and then we look up the line in the magical C<%dbline> hash.
2474
2475=cut
2476
2477 # . command.
826b9a2e 2478 if ($cmd eq '.') {
e22ea7cc 2479 $incr = -1; # stay at current line
69893cff
RGS
2480
2481 # Reset everything to the old location.
e22ea7cc
RF
2482 $start = $line;
2483 $filename = $filename_ini;
2484 *dbline = $main::{ '_<' . $filename };
2485 $max = $#dbline;
69893cff
RGS
2486
2487 # Now where are we?
e22ea7cc
RF
2488 print_lineinfo($position);
2489 next CMD;
826b9a2e 2490 }
69893cff
RGS
2491
2492=head4 C<-> - back one window
2493
2494We change C<$start> to be one window back; if we go back past the first line,
2495we set it to be the first line. We ser C<$incr> to put us back at the
2496currently-executing line, and then put a C<l $start +> (list one window from
2497C<$start>) in C<$cmd> to be executed later.
2498
2499=cut
2500
2501 # - - back a window.
826b9a2e 2502 if ($cmd eq '-') {
e22ea7cc 2503
69893cff 2504 # back up by a window; go to 1 if back too far.
e22ea7cc
RF
2505 $start -= $incr + $window + 1;
2506 $start = 1 if $start <= 0;
2507 $incr = $window - 1;
69893cff
RGS
2508
2509 # Generate and execute a "l +" command (handled below).
e22ea7cc 2510 $cmd = 'l ' . ($start) . '+';
826b9a2e 2511 }
69893cff
RGS
2512
2513=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>, {, {{>
2514
2515In Perl 5.8.0, a realignment of the commands was done to fix up a number of
2516problems, most notably that the default case of several commands destroying
2517the user's work in setting watchpoints, actions, etc. We wanted, however, to
2518retain the old commands for those who were used to using them or who preferred
2519them. At this point, we check for the new commands and call C<cmd_wrapper> to
2520deal with them instead of processing them in-line.
2521
2522=cut
2523
2524 # All of these commands were remapped in perl 5.8.0;
e22ea7cc 2525 # we send them off to the secondary dispatcher (see below).
826b9a2e
SF
2526 if (my ($cmd_letter, $my_arg) = $cmd =~ /\A([aAbBeEhilLMoOPvwW]\b|[<>\{]{1,2})\s*(.*)/so) {
2527 &cmd_wrapper( $cmd_letter, $my_arg, $line );
e22ea7cc 2528 next CMD;
826b9a2e 2529 }
69893cff
RGS
2530
2531=head4 C<y> - List lexicals in higher scope
2532
826b9a2e 2533Uses C<PadWalker> to find the lexicals supplied as arguments in a scope
69893cff
RGS
2534above the current one and then displays then using C<dumpvar.pl>.
2535
2536=cut
2537
826b9a2e
SF
2538 if (my ($match_level, $match_vars)
2539 = $cmd =~ /^y(?:\s+(\d*)\s*(.*))?$/) {
69893cff
RGS
2540
2541 # See if we've got the necessary support.
2542 eval { require PadWalker; PadWalker->VERSION(0.08) }
2543 or &warn(
2544 $@ =~ /locate/
2545 ? "PadWalker module not found - please install\n"
2546 : $@
2547 )
2548 and next CMD;
2549
2550 # Load up dumpvar if we don't have it. If we can, that is.
e81465be 2551 do 'dumpvar.pl' || die $@ unless defined &main::dumpvar;
69893cff
RGS
2552 defined &main::dumpvar
2553 or print $OUT "dumpvar.pl not available.\n"
2554 and next CMD;
2555
2556 # Got all the modules we need. Find them and print them.
826b9a2e 2557 my @vars = split( ' ', $match_vars || '' );
69893cff
RGS
2558
2559 # Find the pad.
826b9a2e 2560 my $h = eval { PadWalker::peek_my( ( $match_level || 0 ) + 1 ) };
69893cff
RGS
2561
2562 # Oops. Can't find it.
2563 $@ and $@ =~ s/ at .*//, &warn($@), next CMD;
2564
2565 # Show the desired vars with dumplex().
2566 my $savout = select($OUT);
2567
2568 # Have dumplex dump the lexicals.
e22ea7cc 2569 dumpvar::dumplex( $_, $h->{$_},
69893cff 2570 defined $option{dumpDepth} ? $option{dumpDepth} : -1,
e22ea7cc
RF
2571 @vars )
2572 for sort keys %$h;
69893cff
RGS
2573 select($savout);
2574 next CMD;
826b9a2e 2575 }
69893cff
RGS
2576
2577=head3 COMMANDS NOT WORKING AFTER PROGRAM ENDS
2578
2579All of the commands below this point don't work after the program being
2580debugged has ended. All of them check to see if the program has ended; this
2581allows the commands to be relocated without worrying about a 'line of
2582demarcation' above which commands can be entered anytime, and below which
2583they can't.
2584
2585=head4 C<n> - single step, but don't trace down into subs
2586
2587Done by setting C<$single> to 2, which forces subs to execute straight through
be9a9b1d 2588when entered (see C<DB::sub>). We also save the C<n> command in C<$laststep>,
826b9a2e 2589so a null command knows what to re-execute.
69893cff
RGS
2590
2591=cut
2592
e22ea7cc 2593 # n - next
826b9a2e 2594 if ($cmd eq 'n') {
69893cff 2595 end_report(), next CMD if $finished and $level <= 1;
e22ea7cc 2596
69893cff
RGS
2597 # Single step, but don't enter subs.
2598 $single = 2;
e22ea7cc 2599
69893cff 2600 # Save for empty command (repeat last).
e22ea7cc
RF
2601 $laststep = $cmd;
2602 last CMD;
826b9a2e 2603 }
69893cff
RGS
2604
2605=head4 C<s> - single-step, entering subs
2606
826b9a2e 2607Sets C<$single> to 1, which causes C<DB::sub> to continue tracing inside
69893cff
RGS
2608subs. Also saves C<s> as C<$lastcmd>.
2609
2610=cut
2611
2612 # s - single step.
826b9a2e 2613 if ($cmd eq 's') {
e22ea7cc 2614
69893cff
RGS
2615 # Get out and restart the command loop if program
2616 # has finished.
e22ea7cc
RF
2617 end_report(), next CMD if $finished and $level <= 1;
2618
69893cff 2619 # Single step should enter subs.
e22ea7cc
RF
2620 $single = 1;
2621
69893cff 2622 # Save for empty command (repeat last).
e22ea7cc
RF
2623 $laststep = $cmd;
2624 last CMD;
826b9a2e 2625 }
69893cff
RGS
2626
2627=head4 C<c> - run continuously, setting an optional breakpoint
2628
2629Most of the code for this command is taken up with locating the optional
2630breakpoint, which is either a subroutine name or a line number. We set
2631the appropriate one-time-break in C<@dbline> and then turn off single-stepping
2632in this and all call levels above this one.
2633
2634=cut
2635
2636 # c - start continuous execution.
ef18ae63 2637 if (($i) = $cmd =~ m#\Ac\b\s*([\w:]*)\s*\z#) {
e22ea7cc 2638
69893cff
RGS
2639 # Hey, show's over. The debugged program finished
2640 # executing already.
2641 end_report(), next CMD if $finished and $level <= 1;
2642
2643 # Capture the place to put a one-time break.
ef18ae63 2644 $subname = $i;
69893cff 2645
e22ea7cc
RF
2646 # Probably not needed, since we finish an interactive
2647 # sub-session anyway...
2648 # local $filename = $filename;
2649 # local *dbline = *dbline; # XXX Would this work?!
69893cff
RGS
2650 #
2651 # The above question wonders if localizing the alias
2652 # to the magic array works or not. Since it's commented
2653 # out, we'll just leave that to speculation for now.
2654
2655 # If the "subname" isn't all digits, we'll assume it
2656 # is a subroutine name, and try to find it.
e22ea7cc
RF
2657 if ( $subname =~ /\D/ ) { # subroutine name
2658 # Qualify it to the current package unless it's
2659 # already qualified.
69893cff
RGS
2660 $subname = $package . "::" . $subname
2661 unless $subname =~ /::/;
e22ea7cc 2662
69893cff
RGS
2663 # find_sub will return "file:line_number" corresponding
2664 # to where the subroutine is defined; we call find_sub,
e22ea7cc 2665 # break up the return value, and assign it in one
69893cff 2666 # operation.
e22ea7cc 2667 ( $file, $i ) = ( find_sub($subname) =~ /^(.*):(.*)$/ );
69893cff
RGS
2668
2669 # Force the line number to be numeric.
e22ea7cc 2670 $i += 0;
69893cff
RGS
2671
2672 # If we got a line number, we found the sub.
e22ea7cc
RF
2673 if ($i) {
2674
69893cff
RGS
2675 # Switch all the debugger's internals around so
2676 # we're actually working with that file.
e22ea7cc
RF
2677 $filename = $file;
2678 *dbline = $main::{ '_<' . $filename };
2679
69893cff 2680 # Mark that there's a breakpoint in this file.
e22ea7cc
RF
2681 $had_breakpoints{$filename} |= 1;
2682
69893cff
RGS
2683 # Scan forward to the first executable line
2684 # after the 'sub whatever' line.
e22ea7cc
RF
2685 $max = $#dbline;
2686 ++$i while $dbline[$i] == 0 && $i < $max;
2687 } ## end if ($i)
69893cff
RGS
2688
2689 # We didn't find a sub by that name.
e22ea7cc
RF
2690 else {
2691 print $OUT "Subroutine $subname not found.\n";
2692 next CMD;
2693 }
2694 } ## end if ($subname =~ /\D/)
69893cff
RGS
2695
2696 # At this point, either the subname was all digits (an
2697 # absolute line-break request) or we've scanned through
2698 # the code following the definition of the sub, looking
2699 # for an executable, which we may or may not have found.
2700 #
2701 # If $i (which we set $subname from) is non-zero, we
e22ea7cc
RF
2702 # got a request to break at some line somewhere. On
2703 # one hand, if there wasn't any real subroutine name
2704 # involved, this will be a request to break in the current
2705 # file at the specified line, so we have to check to make
69893cff
RGS
2706 # sure that the line specified really is breakable.
2707 #
2708 # On the other hand, if there was a subname supplied, the
3c4b39be 2709 # preceding block has moved us to the proper file and
69893cff
RGS
2710 # location within that file, and then scanned forward
2711 # looking for the next executable line. We have to make
2712 # sure that one was found.
2713 #
2714 # On the gripping hand, we can't do anything unless the
2715 # current value of $i points to a valid breakable line.
2716 # Check that.
e22ea7cc
RF
2717 if ($i) {
2718
69893cff 2719 # Breakable?
e22ea7cc
RF
2720 if ( $dbline[$i] == 0 ) {
2721 print $OUT "Line $i not breakable.\n";
2722 next CMD;
2723 }
2724
69893cff 2725 # Yes. Set up the one-time-break sigil.
e22ea7cc 2726 $dbline{$i} =~ s/($|\0)/;9$1/; # add one-time-only b.p.
5d5d9ea3 2727 _enable_breakpoint_temp_enabled_status($filename, $i);
e22ea7cc 2728 } ## end if ($i)
69893cff
RGS
2729
2730 # Turn off stack tracing from here up.
2c247e84
SF
2731 for my $i (0 .. $stack_depth) {
2732 $stack[ $i ] &= ~1;
e22ea7cc
RF
2733 }
2734 last CMD;
ef18ae63 2735 }
69893cff
RGS
2736
2737=head4 C<r> - return from a subroutine
2738
2739For C<r> to work properly, the debugger has to stop execution again
2740immediately after the return is executed. This is done by forcing
2741single-stepping to be on in the call level above the current one. If
2742we are printing return values when a C<r> is executed, set C<$doret>
2743appropriately, and force us out of the command loop.
2744
2745=cut
2746
2747 # r - return from the current subroutine.
ef18ae63 2748 if ($cmd eq 'r') {
e22ea7cc 2749
98dc9551 2750 # Can't do anything if the program's over.
e22ea7cc
RF
2751 end_report(), next CMD if $finished and $level <= 1;
2752
69893cff 2753 # Turn on stack trace.
e22ea7cc
RF
2754 $stack[$stack_depth] |= 1;
2755
69893cff 2756 # Print return value unless the stack is empty.
e22ea7cc
RF
2757 $doret = $option{PrintRet} ? $stack_depth - 1 : -2;
2758 last CMD;
ef18ae63 2759 }
69893cff 2760
69893cff
RGS
2761=head4 C<T> - stack trace
2762
2763Just calls C<DB::print_trace>.
2764
2765=cut
2766
ef18ae63 2767 if ($cmd eq 'T') {
e22ea7cc
RF
2768 print_trace( $OUT, 1 ); # skip DB
2769 next CMD;
ef18ae63 2770 }
69893cff
RGS
2771
2772=head4 C<w> - List window around current line.
2773
2774Just calls C<DB::cmd_w>.
2775
2776=cut
2777
ef18ae63
SF
2778 if (my ($arg) = $cmd =~ /\Aw\b\s*(.*)/s) {
2779 &cmd_w( 'w', $arg );
2780 next CMD;
2781 }
69893cff
RGS
2782
2783=head4 C<W> - watch-expression processing.
2784
b570d64b 2785Just calls C<DB::cmd_W>.
69893cff
RGS
2786
2787=cut
2788
ef18ae63
SF
2789 if (my ($arg) = $cmd =~ /\AW\b\s*(.*)/s) {
2790 &cmd_W( 'W', $arg );
2791 next CMD;
2792 }
69893cff
RGS
2793
2794=head4 C</> - search forward for a string in the source
2795
ef18ae63 2796We take the argument and treat it as a pattern. If it turns out to be a
69893cff 2797bad one, we return the error we got from trying to C<eval> it and exit.
ef18ae63 2798If not, we create some code to do the search and C<eval> it so it can't
69893cff
RGS
2799mess us up.
2800
2801=cut
2802
ef18ae63
SF
2803 # The pattern as a string.
2804 use vars qw($inpat);
69893cff 2805
ef18ae63 2806 if (($inpat) = $cmd =~ m#\A/(.*)\z#) {
69893cff
RGS
2807
2808 # Remove the final slash.
e22ea7cc 2809 $inpat =~ s:([^\\])/$:$1:;
69893cff
RGS
2810
2811 # If the pattern isn't null ...
e22ea7cc 2812 if ( $inpat ne "" ) {
69893cff
RGS
2813
2814 # Turn of warn and die procesing for a bit.
e22ea7cc
RF
2815 local $SIG{__DIE__};
2816 local $SIG{__WARN__};
69893cff
RGS
2817
2818 # Create the pattern.
e22ea7cc
RF
2819 eval '$inpat =~ m' . "\a$inpat\a";
2820 if ( $@ ne "" ) {
2821
69893cff 2822 # Oops. Bad pattern. No biscuit.
e22ea7cc 2823 # Print the eval error and go back for more
69893cff 2824 # commands.
e22ea7cc
RF
2825 print $OUT "$@";
2826 next CMD;
2827 }
2828 $pat = $inpat;
2829 } ## end if ($inpat ne "")
69893cff
RGS
2830
2831 # Set up to stop on wrap-around.
e22ea7cc 2832 $end = $start;
69893cff
RGS
2833
2834 # Don't move off the current line.
e22ea7cc 2835 $incr = -1;
69893cff
RGS
2836
2837 # Done in eval so nothing breaks if the pattern
2838 # does something weird.
e22ea7cc
RF
2839 eval '
2840 for (;;) {
69893cff 2841 # Move ahead one line.
e22ea7cc 2842 ++$start;
69893cff
RGS
2843
2844 # Wrap if we pass the last line.
e22ea7cc 2845 $start = 1 if ($start > $max);
69893cff
RGS
2846
2847 # Stop if we have gotten back to this line again,
e22ea7cc 2848 last if ($start == $end);
69893cff
RGS
2849
2850 # A hit! (Note, though, that we are doing
2851 # case-insensitive matching. Maybe a qr//
2852 # expression would be better, so the user could
2853 # do case-sensitive matching if desired.
e22ea7cc
RF
2854 if ($dbline[$start] =~ m' . "\a$pat\a" . 'i) {
2855 if ($slave_editor) {
69893cff 2856 # Handle proper escaping in the slave.
e22ea7cc 2857 print $OUT "\032\032$filename:$start:0\n";
b570d64b 2858 }
e22ea7cc 2859 else {
69893cff 2860 # Just print the line normally.
e22ea7cc
RF
2861 print $OUT "$start:\t",$dbline[$start],"\n";
2862 }
69893cff 2863 # And quit since we found something.
e22ea7cc
RF
2864 last;
2865 }
2866 } ';
2867
69893cff 2868 # If we wrapped, there never was a match.
e22ea7cc
RF
2869 print $OUT "/$pat/: not found\n" if ( $start == $end );
2870 next CMD;
ef18ae63 2871 }
69893cff
RGS
2872
2873=head4 C<?> - search backward for a string in the source
2874
2875Same as for C</>, except the loop runs backwards.
2876
2877=cut
2878
2879 # ? - backward pattern search.
ef18ae63 2880 if (my ($inpat) = $cmd =~ m#\A\?(.*)\z#) {
69893cff
RGS
2881
2882 # Get the pattern, remove trailing question mark.
e22ea7cc 2883 $inpat =~ s:([^\\])\?$:$1:;
69893cff
RGS
2884
2885 # If we've got one ...
e22ea7cc 2886 if ( $inpat ne "" ) {
69893cff
RGS
2887
2888 # Turn off die & warn handlers.
e22ea7cc
RF
2889 local $SIG{__DIE__};
2890 local $SIG{__WARN__};
2891 eval '$inpat =~ m' . "\a$inpat\a";
2892
2893 if ( $@ ne "" ) {
2894
69893cff 2895 # Ouch. Not good. Print the error.
e22ea7cc
RF
2896 print $OUT $@;
2897 next CMD;
2898 }
2899 $pat = $inpat;
69893cff 2900 } ## end if ($inpat ne "")
e22ea7cc 2901
69893cff 2902 # Where we are now is where to stop after wraparound.
e22ea7cc 2903 $end = $start;
69893cff
RGS
2904
2905 # Don't move away from this line.
e22ea7cc 2906 $incr = -1;
69893cff
RGS
2907
2908 # Search inside the eval to prevent pattern badness
2909 # from killing us.
e22ea7cc
RF
2910 eval '
2911 for (;;) {
69893cff 2912 # Back up a line.
e22ea7cc 2913 --$start;
69893cff
RGS
2914
2915 # Wrap if we pass the first line.
e22ea7cc
RF
2916
2917 $start = $max if ($start <= 0);
69893cff
RGS
2918
2919 # Quit if we get back where we started,
e22ea7cc 2920 last if ($start == $end);
69893cff
RGS
2921
2922 # Match?
e22ea7cc
RF
2923 if ($dbline[$start] =~ m' . "\a$pat\a" . 'i) {
2924 if ($slave_editor) {
69893cff 2925 # Yep, follow slave editor requirements.
e22ea7cc 2926 print $OUT "\032\032$filename:$start:0\n";
b570d64b 2927 }
e22ea7cc 2928 else {
69893cff 2929 # Yep, just print normally.
e22ea7cc
RF
2930 print $OUT "$start:\t",$dbline[$start],"\n";
2931 }
69893cff
RGS
2932
2933 # Found, so done.
e22ea7cc
RF
2934 last;
2935 }
2936 } ';
2937
2938 # Say we failed if the loop never found anything,
2939 print $OUT "?$pat?: not found\n" if ( $start == $end );
2940 next CMD;
ef18ae63 2941 }
69893cff
RGS
2942
2943=head4 C<$rc> - Recall command
2944
2945Manages the commands in C<@hist> (which is created if C<Term::ReadLine> reports
2946that the terminal supports history). It find the the command required, puts it
2947into C<$cmd>, and redoes the loop to execute it.
2948
2949=cut
2950
e22ea7cc 2951 # $rc - recall command.
ef18ae63 2952 if (my ($minus, $arg) = $cmd =~ m#\A$rc+\s*(-)?(\d+)?\z#) {
69893cff
RGS
2953
2954 # No arguments, take one thing off history.
e22ea7cc 2955 pop(@hist) if length($cmd) > 1;
69893cff 2956
e22ea7cc 2957 # Relative (- found)?
69893cff 2958 # Y - index back from most recent (by 1 if bare minus)
e22ea7cc 2959 # N - go to that particular command slot or the last
69893cff 2960 # thing if nothing following.
ef18ae63 2961 $i = $minus ? ( $#hist - ( $arg || 1 ) ) : ( $arg || $#hist );
69893cff
RGS
2962
2963 # Pick out the command desired.
e22ea7cc 2964 $cmd = $hist[$i];
69893cff
RGS
2965
2966 # Print the command to be executed and restart the loop
2967 # with that command in the buffer.
e22ea7cc
RF
2968 print $OUT $cmd, "\n";
2969 redo CMD;
ef18ae63 2970 }
69893cff
RGS
2971
2972=head4 C<$sh$sh> - C<system()> command
2973
2974Calls the C<DB::system()> to handle the command. This keeps the C<STDIN> and
2975C<STDOUT> from getting messed up.
2976
2977=cut
2978
2979 # $sh$sh - run a shell command (if it's all ASCII).
2980 # Can't run shell commands with Unicode in the debugger, hmm.
ef18ae63 2981 if (my ($arg) = $cmd =~ m#\A$sh$sh\s*(.*)#ms) {
e22ea7cc 2982
69893cff 2983 # System it.
ef18ae63 2984 &system($arg);
e22ea7cc 2985 next CMD;
ef18ae63 2986 }
69893cff
RGS
2987
2988=head4 C<$rc I<pattern> $rc> - Search command history
2989
2990Another command to manipulate C<@hist>: this one searches it with a pattern.
be9a9b1d 2991If a command is found, it is placed in C<$cmd> and executed via C<redo>.
69893cff
RGS
2992
2993=cut
2994
e22ea7cc 2995 # $rc pattern $rc - find a command in the history.
ef18ae63 2996 if (my ($arg) = $cmd =~ /\A$rc([^$rc].*)\z/) {
e22ea7cc 2997
69893cff 2998 # Create the pattern to use.
ef18ae63 2999 $pat = "^$arg";
69893cff
RGS
3000
3001 # Toss off last entry if length is >1 (and it always is).
e22ea7cc 3002 pop(@hist) if length($cmd) > 1;
69893cff
RGS
3003
3004 # Look backward through the history.
72d7d80d 3005 for ( $i = $#hist ; $i ; --$i ) {
69893cff 3006 # Stop if we find it.
e22ea7cc
RF
3007 last if $hist[$i] =~ /$pat/;
3008 }
3009
3010 if ( !$i ) {
69893cff 3011
69893cff 3012 # Never found it.
e22ea7cc
RF
3013 print $OUT "No such command!\n\n";
3014 next CMD;
3015 }
69893cff
RGS
3016
3017 # Found it. Put it in the buffer, print it, and process it.
e22ea7cc
RF
3018 $cmd = $hist[$i];
3019 print $OUT $cmd, "\n";
3020 redo CMD;
ef18ae63 3021 }
69893cff 3022
ef18ae63 3023=head4 C<$sh> - Invoke a shell
69893cff
RGS
3024
3025Uses C<DB::system> to invoke a shell.
3026
3027=cut
3028
3029 # $sh - start a shell.
ef18ae63 3030 if ($cmd =~ /\A$sh\z/) {
e22ea7cc 3031
69893cff
RGS
3032 # Run the user's shell. If none defined, run Bourne.
3033 # We resume execution when the shell terminates.
e22ea7cc
RF
3034 &system( $ENV{SHELL} || "/bin/sh" );
3035 next CMD;
ef18ae63 3036 }
69893cff
RGS
3037
3038=head4 C<$sh I<command>> - Force execution of a command in a shell
3039
3040Like the above, but the command is passed to the shell. Again, we use
3041C<DB::system> to avoid problems with C<STDIN> and C<STDOUT>.
3042
3043=cut
3044
3045 # $sh command - start a shell and run a command in it.
ef18ae63 3046 if (my ($arg) = $cmd =~ m#\A$sh\s*(.*)#ms) {
e22ea7cc
RF
3047
3048 # XXX: using csh or tcsh destroys sigint retvals!
3049 #&system($1); # use this instead
69893cff
RGS
3050
3051 # use the user's shell, or Bourne if none defined.
ef18ae63 3052 &system( $ENV{SHELL} || "/bin/sh", "-c", $arg );
e22ea7cc 3053 next CMD;
ef18ae63 3054 }
69893cff
RGS
3055
3056=head4 C<H> - display commands in history
3057
3058Prints the contents of C<@hist> (if any).
3059
3060=cut
3061
ef18ae63 3062 if ($cmd =~ /\AH\b\s*\*/) {
7fddc82f
RF
3063 @hist = @truehist = ();
3064 print $OUT "History cleansed\n";
3065 next CMD;
ef18ae63 3066 }
e22ea7cc 3067
ef18ae63
SF
3068 if (my ($num)
3069 = $cmd =~ /\AH\b\s*(?:-(\d+))?/) {
e22ea7cc
RF
3070
3071 # Anything other than negative numbers is ignored by
69893cff 3072 # the (incorrect) pattern, so this test does nothing.
ef18ae63 3073 $end = $num ? ( $#hist - $num ) : 0;
69893cff
RGS
3074
3075 # Set to the minimum if less than zero.
e22ea7cc 3076 $hist = 0 if $hist < 0;
69893cff 3077
e22ea7cc 3078 # Start at the end of the array.
69893cff
RGS
3079 # Stay in while we're still above the ending value.
3080 # Tick back by one each time around the loop.
72d7d80d 3081 for ( $i = $#hist ; $i > $end ; $i-- ) {
69893cff
RGS
3082
3083 # Print the command unless it has no arguments.
e22ea7cc
RF
3084 print $OUT "$i: ", $hist[$i], "\n"
3085 unless $hist[$i] =~ /^.?$/;
3086 }
3087 next CMD;
ef18ae63 3088 }
69893cff
RGS
3089
3090=head4 C<man, doc, perldoc> - look up documentation
3091
3092Just calls C<runman()> to print the appropriate document.
3093
3094=cut
3095
e22ea7cc 3096 # man, perldoc, doc - show manual pages.
ef18ae63
SF
3097 if (my ($man_page)
3098 = $cmd =~ /\A(?:man|(?:perl)?doc)\b(?:\s+([^(]*))?\z/) {
3099 runman($man_page);
e22ea7cc 3100 next CMD;
ef18ae63 3101 }
69893cff
RGS
3102
3103=head4 C<p> - print
3104
3105Builds a C<print EXPR> expression in the C<$cmd>; this will get executed at
3106the bottom of the loop.
3107
3108=cut
3109
ef18ae63 3110 my $print_cmd = 'print {$DB::OUT} ';
69893cff 3111 # p - print (no args): print $_.
ef18ae63
SF
3112 if ($cmd eq 'p') {
3113 $cmd = $print_cmd . '$_';
3114 }
69893cff
RGS
3115
3116 # p - print the given expression.
ef18ae63 3117 $cmd =~ s/\Ap\b/$print_cmd /;
69893cff
RGS
3118
3119=head4 C<=> - define command alias
3120
3121Manipulates C<%alias> to add or list command aliases.
3122
3123=cut
3124
e22ea7cc 3125 # = - set up a command alias.
ef18ae63 3126 if ($cmd =~ s/\A=\s*//) {
e22ea7cc
RF
3127 my @keys;
3128 if ( length $cmd == 0 ) {
3129
69893cff 3130 # No args, get current aliases.
e22ea7cc
RF
3131 @keys = sort keys %alias;
3132 }
3133 elsif ( my ( $k, $v ) = ( $cmd =~ /^(\S+)\s+(\S.*)/ ) ) {
3134
69893cff
RGS
3135 # Creating a new alias. $k is alias name, $v is
3136 # alias value.
3137
e22ea7cc
RF
3138 # can't use $_ or kill //g state
3139 for my $x ( $k, $v ) {
3140
3141 # Escape "alarm" characters.
3142 $x =~ s/\a/\\a/g;
3143 }
69893cff
RGS
3144
3145 # Substitute key for value, using alarm chars
e22ea7cc 3146 # as separators (which is why we escaped them in
69893cff 3147 # the command).
e22ea7cc 3148 $alias{$k} = "s\a$k\a$v\a";
69893cff
RGS
3149
3150 # Turn off standard warn and die behavior.
e22ea7cc
RF
3151 local $SIG{__DIE__};
3152 local $SIG{__WARN__};
69893cff
RGS
3153
3154 # Is it valid Perl?
e22ea7cc
RF
3155 unless ( eval "sub { s\a$k\a$v\a }; 1" ) {
3156
69893cff 3157 # Nope. Bad alias. Say so and get out.
e22ea7cc
RF
3158 print $OUT "Can't alias $k to $v: $@\n";
3159 delete $alias{$k};
3160 next CMD;
3161 }
3162
69893cff 3163 # We'll only list the new one.
e22ea7cc 3164 @keys = ($k);
69893cff
RGS
3165 } ## end elsif (my ($k, $v) = ($cmd...
3166
3167 # The argument is the alias to list.
e22ea7cc
RF
3168 else {
3169 @keys = ($cmd);
3170 }
69893cff
RGS
3171
3172 # List aliases.
e22ea7cc
RF
3173 for my $k (@keys) {
3174
98dc9551 3175 # Messy metaquoting: Trim the substitution code off.
69893cff
RGS
3176 # We use control-G as the delimiter because it's not
3177 # likely to appear in the alias.
e22ea7cc
RF
3178 if ( ( my $v = $alias{$k} ) =~ s\as\a$k\a(.*)\a$\a1\a ) {
3179
69893cff 3180 # Print the alias.
e22ea7cc
RF
3181 print $OUT "$k\t= $1\n";
3182 }
3183 elsif ( defined $alias{$k} ) {
3184
69893cff 3185 # Couldn't trim it off; just print the alias code.
e22ea7cc
RF
3186 print $OUT "$k\t$alias{$k}\n";
3187 }
3188 else {
3189
69893cff 3190 # No such, dude.
e22ea7cc
RF
3191 print "No alias for $k\n";
3192 }
69893cff 3193 } ## end for my $k (@keys)
e22ea7cc 3194 next CMD;
ef18ae63 3195 }
69893cff
RGS
3196
3197=head4 C<source> - read commands from a file.
3198
3199Opens a lexical filehandle and stacks it on C<@cmdfhs>; C<DB::readline> will
3200pick it up.
3201
3202=cut
3203
e22ea7cc 3204 # source - read commands from a file (or pipe!) and execute.
ef18ae63
SF
3205 if (my ($sourced_fn) = $cmd =~ /\Asource\s+(.*\S)/) {
3206 if ( open my $fh, $sourced_fn ) {
e22ea7cc 3207
69893cff 3208 # Opened OK; stick it in the list of file handles.
e22ea7cc
RF
3209 push @cmdfhs, $fh;
3210 }
3211 else {
3212
3213 # Couldn't open it.
ef18ae63 3214 &warn("Can't execute '$sourced_fn': $!\n");
e22ea7cc
RF
3215 }
3216 next CMD;
ef18ae63 3217 }
69893cff 3218
ef18ae63
SF
3219 if (my ($which_cmd, $position)
3220 = $cmd =~ /^(enable|disable)\s+(\S+)\s*$/) {
e09195af
SF
3221
3222 my ($fn, $line_num);
3223 if ($position =~ m{\A\d+\z})
3224 {
3225 $fn = $filename;
3226 $line_num = $position;
3227 }
ef18ae63
SF
3228 elsif (my ($new_fn, $new_line_num)
3229 = $position =~ m{\A(.*):(\d+)\z}) {
3230 ($fn, $line_num) = ($new_fn, $new_line_num);
e09195af
SF
3231 }
3232 else
3233 {
3234 &warn("Wrong spec for enable/disable argument.\n");
3235 }
3236
3237 if (defined($fn)) {
3238 if (_has_breakpoint_data_ref($fn, $line_num)) {
3239 _set_breakpoint_enabled_status($fn, $line_num,
ef18ae63 3240 ($which_cmd eq 'enable' ? 1 : '')
e09195af
SF
3241 );
3242 }
3243 else {
3244 &warn("No breakpoint set at ${fn}:${line_num}\n");
3245 }
3246 }
3247
3248 next CMD;
ef18ae63 3249 }
e09195af 3250
69893cff
RGS
3251=head4 C<save> - send current history to a file
3252
3253Takes the complete history, (not the shrunken version you see with C<H>),
3254and saves it to the given filename, so it can be replayed using C<source>.
3255
3256Note that all C<^(save|source)>'s are commented out with a view to minimise recursion.
3257
3258=cut
3259
3260 # save source - write commands to a file for later use
ef18ae63
SF
3261 if (my ($new_fn) = $cmd =~ /\Asave\s*(.*)\z/) {
3262 my $filename = $new_fn || '.perl5dbrc'; # default?
3263 if ( open my $fh, '>', $filename ) {
e22ea7cc
RF
3264
3265 # chomp to remove extraneous newlines from source'd files
3266 chomp( my @truelist =
3267 map { m/^\s*(save|source)/ ? "#$_" : $_ }
3268 @truehist );
3269 print $fh join( "\n", @truelist );
69893cff 3270 print "commands saved in $file\n";
e22ea7cc
RF
3271 }
3272 else {
ef18ae63 3273 &warn("Can't save debugger commands in '$new_fn': $!\n");
69893cff
RGS
3274 }
3275 next CMD;
ef18ae63 3276 }
69893cff 3277
7fddc82f
RF
3278=head4 C<R> - restart
3279
ef18ae63 3280Restart the debugger session.
7fddc82f
RF
3281
3282=head4 C<rerun> - rerun the current session
3283
3284Return to any given position in the B<true>-history list
3285
3286=cut
3287
3288 # R - restart execution.
3289 # rerun - controlled restart execution.
ff41e38d
SF
3290 if (my ($cmd_cmd, $cmd_params) =
3291 $cmd =~ /\A((?:R)|(?:rerun\s*(.*)))\z/) {
3292 my @args = ($cmd_cmd eq 'R' ? restart() : rerun($cmd_params));
7fddc82f 3293
ca28b541
AP
3294 # Close all non-system fds for a clean restart. A more
3295 # correct method would be to close all fds that were not
3296 # open when the process started, but this seems to be
3297 # hard. See "debugger 'R'estart and open database
3298 # connections" on p5p.
3299
47d3bbda 3300 my $max_fd = 1024; # default if POSIX can't be loaded
ca28b541 3301 if (eval { require POSIX }) {
5332cc68 3302 eval { $max_fd = POSIX::sysconf(POSIX::_SC_OPEN_MAX()) };
ca28b541
AP
3303 }
3304
3305 if (defined $max_fd) {
3306 foreach ($^F+1 .. $max_fd-1) {
3307 next unless open FD_TO_CLOSE, "<&=$_";
3308 close(FD_TO_CLOSE);
3309 }
3310 }
3311
7fddc82f
RF
3312 # And run Perl again. We use exec() to keep the
3313 # PID stable (and that way $ini_pids is still valid).
3314 exec(@args) || print $OUT "exec failed: $!\n";
3315
3316 last CMD;
ff41e38d 3317 }
7fddc82f 3318
69893cff
RGS
3319=head4 C<|, ||> - pipe output through the pager.
3320
be9a9b1d 3321For C<|>, we save C<OUT> (the debugger's output filehandle) and C<STDOUT>
69893cff
RGS
3322(the program's standard output). For C<||>, we only save C<OUT>. We open a
3323pipe to the pager (restoring the output filehandles if this fails). If this
b570d64b 3324is the C<|> command, we also set up a C<SIGPIPE> handler which will simply
69893cff
RGS
3325set C<$signal>, sending us back into the debugger.
3326
3327We then trim off the pipe symbols and C<redo> the command loop at the
3328C<PIPE> label, causing us to evaluate the command in C<$cmd> without
3329reading another.
3330
3331=cut
3332
3333 # || - run command in the pager, with output to DB::OUT.
ff41e38d 3334 if ($cmd =~ m#\A\|\|?\s*[^|]#) {
e22ea7cc
RF
3335 if ( $pager =~ /^\|/ ) {
3336
69893cff 3337 # Default pager is into a pipe. Redirect I/O.
e22ea7cc
RF
3338 open( SAVEOUT, ">&STDOUT" )
3339 || &warn("Can't save STDOUT");
3340 open( STDOUT, ">&OUT" )
3341 || &warn("Can't redirect STDOUT");
69893cff 3342 } ## end if ($pager =~ /^\|/)
e22ea7cc
RF
3343 else {
3344
69893cff 3345 # Not into a pipe. STDOUT is safe.
e22ea7cc
RF
3346 open( SAVEOUT, ">&OUT" ) || &warn("Can't save DB::OUT");
3347 }
69893cff
RGS
3348
3349 # Fix up environment to record we have less if so.
e22ea7cc
RF
3350 fix_less();
3351
3352 unless ( $piped = open( OUT, $pager ) ) {
69893cff 3353
69893cff 3354 # Couldn't open pipe to pager.
1f874cb6 3355 &warn("Can't pipe output to '$pager'");
e22ea7cc
RF
3356 if ( $pager =~ /^\|/ ) {
3357
69893cff 3358 # Redirect I/O back again.
e22ea7cc
RF
3359 open( OUT, ">&STDOUT" ) # XXX: lost message
3360 || &warn("Can't restore DB::OUT");
3361 open( STDOUT, ">&SAVEOUT" )
3362 || &warn("Can't restore STDOUT");
3363 close(SAVEOUT);
69893cff 3364 } ## end if ($pager =~ /^\|/)
e22ea7cc
RF
3365 else {
3366
69893cff 3367 # Redirect I/O. STDOUT already safe.
e22ea7cc
RF
3368 open( OUT, ">&STDOUT" ) # XXX: lost message
3369 || &warn("Can't restore DB::OUT");
3370 }
3371 next CMD;
69893cff
RGS
3372 } ## end unless ($piped = open(OUT,...
3373
3374 # Set up broken-pipe handler if necessary.
e22ea7cc
RF
3375 $SIG{PIPE} = \&DB::catch
3376 if $pager =~ /^\|/
3377 && ( "" eq $SIG{PIPE} || "DEFAULT" eq $SIG{PIPE} );
69893cff 3378
70c9432b
SF
3379 OUT->autoflush(1);
3380 # Save current filehandle, and put it back.
e22ea7cc 3381 $selected = select(OUT);
69893cff 3382 # Don't put it back if pager was a pipe.
e22ea7cc 3383 select($selected), $selected = "" unless $cmd =~ /^\|\|/;
69893cff
RGS
3384
3385 # Trim off the pipe symbols and run the command now.
ff41e38d 3386 $cmd =~ s#\A\|+\s*##;
e22ea7cc 3387 redo PIPE;
ff41e38d 3388 }
69893cff
RGS
3389
3390=head3 END OF COMMAND PARSING
3391
ff41e38d
SF
3392Anything left in C<$cmd> at this point is a Perl expression that we want to
3393evaluate. We'll always evaluate in the user's context, and fully qualify
69893cff
RGS
3394any variables we might want to address in the C<DB> package.
3395
3396=cut
3397
3398 # t - turn trace on.
ff41e38d
SF
3399 if ($cmd =~ s#\At\s+(\d+)?#\$DB::trace |= 1;\n#) {
3400 my $trace_arg = $1;
3401 $trace_to_depth = $trace_arg ? $stack_depth||0 + $1 : 1E9;
3402 }
69893cff
RGS
3403
3404 # s - single-step. Remember the last command was 's'.
ff41e38d
SF
3405 if ($cmd =~ s/\As\s/\$DB::single = 1;\n/) {
3406 $laststep = 's';
3407 }
69893cff
RGS
3408
3409 # n - single-step, but not into subs. Remember last command
e22ea7cc 3410 # was 'n'.
ff41e38d
SF
3411 if ($cmd =~ s#\An\s#\$DB::single = 2;\n#) {
3412 $laststep = 'n';
3413 }
69893cff 3414
e22ea7cc 3415 } # PIPE:
69893cff 3416
e22ea7cc 3417 # Make sure the flag that says "the debugger's running" is
69893cff 3418 # still on, to make sure we get control again.
e22ea7cc 3419 $evalarg = "\$^D = \$^D | \$DB::db_stop;\n$cmd";
69893cff
RGS
3420
3421 # Run *our* eval that executes in the caller's context.
e22ea7cc 3422 &eval;
69893cff
RGS
3423
3424 # Turn off the one-time-dump stuff now.
e22ea7cc
RF
3425 if ($onetimeDump) {
3426 $onetimeDump = undef;
69893cff 3427 $onetimedumpDepth = undef;
e22ea7cc
RF
3428 }
3429 elsif ( $term_pid == $$ ) {
c7e68384
IZ
3430 eval { # May run under miniperl, when not available...
3431 STDOUT->flush();
3432 STDERR->flush();
3433 };
e22ea7cc 3434
69893cff 3435 # XXX If this is the master pid, print a newline.
e22ea7cc
RF
3436 print $OUT "\n";
3437 }
3438 } ## end while (($term || &setterm...
69893cff
RGS
3439
3440=head3 POST-COMMAND PROCESSING
3441
3442After each command, we check to see if the command output was piped anywhere.
3443If so, we go through the necessary code to unhook the pipe and go back to
3444our standard filehandles for input and output.
3445
3446=cut
3447
e22ea7cc 3448 continue { # CMD:
69893cff
RGS
3449
3450 # At the end of every command:
e22ea7cc
RF
3451 if ($piped) {
3452
69893cff 3453 # Unhook the pipe mechanism now.
e22ea7cc
RF
3454 if ( $pager =~ /^\|/ ) {
3455
69893cff 3456 # No error from the child.
e22ea7cc 3457 $? = 0;
69893cff 3458
e22ea7cc
RF
3459 # we cannot warn here: the handle is missing --tchrist
3460 close(OUT) || print SAVEOUT "\nCan't close DB::OUT\n";
69893cff 3461
e22ea7cc 3462 # most of the $? crud was coping with broken cshisms
69893cff 3463 # $? is explicitly set to 0, so this never runs.
e22ea7cc 3464 if ($?) {
1f874cb6 3465 print SAVEOUT "Pager '$pager' failed: ";
e22ea7cc
RF
3466 if ( $? == -1 ) {
3467 print SAVEOUT "shell returned -1\n";
3468 }
3469 elsif ( $? >> 8 ) {
3470 print SAVEOUT ( $? & 127 )
3471 ? " (SIG#" . ( $? & 127 ) . ")"
3472 : "", ( $? & 128 ) ? " -- core dumped" : "", "\n";
3473 }
3474 else {
3475 print SAVEOUT "status ", ( $? >> 8 ), "\n";
3476 }
69893cff
RGS
3477 } ## end if ($?)
3478
e22ea7cc 3479 # Reopen filehandle for our output (if we can) and
69893cff 3480 # restore STDOUT (if we can).
e22ea7cc
RF
3481 open( OUT, ">&STDOUT" ) || &warn("Can't restore DB::OUT");
3482 open( STDOUT, ">&SAVEOUT" )
3483 || &warn("Can't restore STDOUT");
69893cff
RGS
3484
3485 # Turn off pipe exception handler if necessary.
e22ea7cc 3486 $SIG{PIPE} = "DEFAULT" if $SIG{PIPE} eq \&DB::catch;
69893cff 3487
e22ea7cc
RF
3488 # Will stop ignoring SIGPIPE if done like nohup(1)
3489 # does SIGINT but Perl doesn't give us a choice.
69893cff 3490 } ## end if ($pager =~ /^\|/)
e22ea7cc
RF
3491 else {
3492
69893cff 3493 # Non-piped "pager". Just restore STDOUT.
e22ea7cc
RF
3494 open( OUT, ">&SAVEOUT" ) || &warn("Can't restore DB::OUT");
3495 }
69893cff
RGS
3496
3497 # Close filehandle pager was using, restore the normal one
3498 # if necessary,
3499 close(SAVEOUT);
e22ea7cc 3500 select($selected), $selected = "" unless $selected eq "";
69893cff
RGS
3501
3502 # No pipes now.
e22ea7cc 3503 $piped = "";
69893cff 3504 } ## end if ($piped)
e22ea7cc 3505 } # CMD:
69893cff
RGS
3506
3507=head3 COMMAND LOOP TERMINATION
3508
3509When commands have finished executing, we come here. If the user closed the
3510input filehandle, we turn on C<$fall_off_end> to emulate a C<q> command. We
3511evaluate any post-prompt items. We restore C<$@>, C<$!>, C<$^E>, C<$,>, C<$/>,
3512C<$\>, and C<$^W>, and return a null list as expected by the Perl interpreter.
3513The interpreter will then execute the next line and then return control to us
3514again.
3515
3516=cut
3517
3518 # No more commands? Quit.
1f874cb6 3519 $fall_off_end = 1 unless defined $cmd; # Emulate 'q' on EOF
69893cff
RGS
3520
3521 # Evaluate post-prompt commands.
e22ea7cc
RF
3522 foreach $evalarg (@$post) {
3523 &eval;
3524 }
3525 } # if ($single || $signal)
69893cff
RGS
3526
3527 # Put the user's globals back where you found them.
e22ea7cc 3528 ( $@, $!, $^E, $,, $/, $\, $^W ) = @saved;
69893cff
RGS
3529 ();
3530} ## end sub DB
3531
3532# The following code may be executed now:
3533# BEGIN {warn 4}
3534
3535=head2 sub
3536
b570d64b 3537C<sub> is called whenever a subroutine call happens in the program being
69893cff
RGS
3538debugged. The variable C<$DB::sub> contains the name of the subroutine
3539being called.
3540
3541The core function of this subroutine is to actually call the sub in the proper
3542context, capturing its output. This of course causes C<DB::DB> to get called
3543again, repeating until the subroutine ends and returns control to C<DB::sub>
3544again. Once control returns, C<DB::sub> figures out whether or not to dump the
3545return value, and returns its captured copy of the return value as its own
3546return value. The value then feeds back into the program being debugged as if
3547C<DB::sub> hadn't been there at all.
3548
3549C<sub> does all the work of printing the subroutine entry and exit messages
3550enabled by setting C<$frame>. It notes what sub the autoloader got called for,
b570d64b 3551and also prints the return value if needed (for the C<r> command and if
69893cff
RGS
3552the 16 bit is set in C<$frame>).