xref: /openbsd/gnu/usr.bin/binutils/gdb/event-top.c (revision 11efff7f)
1 /* Top level stuff for GDB, the GNU debugger.
2    Copyright 1999, 2000, 2001, 2002, 2004 Free Software Foundation, Inc.
3    Written by Elena Zannoni <ezannoni@cygnus.com> of Cygnus Solutions.
4 
5    This file is part of GDB.
6 
7    This program is free software; you can redistribute it and/or modify
8    it under the terms of the GNU General Public License as published by
9    the Free Software Foundation; either version 2 of the License, or
10    (at your option) any later version.
11 
12    This program is distributed in the hope that it will be useful,
13    but WITHOUT ANY WARRANTY; without even the implied warranty of
14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15    GNU General Public License for more details.
16 
17    You should have received a copy of the GNU General Public License
18    along with this program; if not, write to the Free Software
19    Foundation, Inc., 59 Temple Place - Suite 330,
20    Boston, MA 02111-1307, USA. */
21 
22 #include "defs.h"
23 #include "top.h"
24 #include "inferior.h"
25 #include "target.h"
26 #include "terminal.h"		/* for job_control */
27 #include "event-loop.h"
28 #include "event-top.h"
29 #include "interps.h"
30 #include <signal.h>
31 
32 /* For dont_repeat() */
33 #include "gdbcmd.h"
34 
35 /* readline include files */
36 #include "readline/readline.h"
37 #include "readline/history.h"
38 
39 /* readline defines this.  */
40 #undef savestring
41 
42 static void rl_callback_read_char_wrapper (gdb_client_data client_data);
43 static void command_line_handler (char *rl);
44 static void command_line_handler_continuation (struct continuation_arg *arg);
45 static void change_line_handler (void);
46 static void change_annotation_level (void);
47 static void command_handler (char *command);
48 static void async_do_nothing (gdb_client_data arg);
49 static void async_disconnect (gdb_client_data arg);
50 static void async_stop_sig (gdb_client_data arg);
51 static void async_float_handler (gdb_client_data arg);
52 
53 /* Signal handlers. */
54 static void handle_sigquit (int sig);
55 static void handle_sighup (int sig);
56 static void handle_sigfpe (int sig);
57 #if defined(SIGWINCH) && defined(SIGWINCH_HANDLER)
58 static void handle_sigwinch (int sig);
59 #endif
60 
61 /* Functions to be invoked by the event loop in response to
62    signals. */
63 static void async_do_nothing (gdb_client_data);
64 static void async_disconnect (gdb_client_data);
65 static void async_float_handler (gdb_client_data);
66 static void async_stop_sig (gdb_client_data);
67 
68 /* Readline offers an alternate interface, via callback
69    functions. These are all included in the file callback.c in the
70    readline distribution.  This file provides (mainly) a function, which
71    the event loop uses as callback (i.e. event handler) whenever an event
72    is detected on the standard input file descriptor.
73    readline_callback_read_char is called (by the GDB event loop) whenever
74    there is a new character ready on the input stream. This function
75    incrementally builds a buffer internal to readline where it
76    accumulates the line read up to the point of invocation.  In the
77    special case in which the character read is newline, the function
78    invokes a GDB supplied callback routine, which does the processing of
79    a full command line.  This latter routine is the asynchronous analog
80    of the old command_line_input in gdb. Instead of invoking (and waiting
81    for) readline to read the command line and pass it back to
82    command_loop for processing, the new command_line_handler function has
83    the command line already available as its parameter.  INPUT_HANDLER is
84    to be set to the function that readline will invoke when a complete
85    line of input is ready.  CALL_READLINE is to be set to the function
86    that readline offers as callback to the event_loop. */
87 
88 void (*input_handler) (char *);
89 void (*call_readline) (gdb_client_data);
90 
91 /* Important variables for the event loop. */
92 
93 /* This is used to determine if GDB is using the readline library or
94    its own simplified form of readline. It is used by the asynchronous
95    form of the set editing command.
96    ezannoni: as of 1999-04-29 I expect that this
97    variable will not be used after gdb is changed to use the event
98    loop as default engine, and event-top.c is merged into top.c. */
99 int async_command_editing_p;
100 
101 /* This variable contains the new prompt that the user sets with the
102    set prompt command. */
103 char *new_async_prompt;
104 
105 /* This is the annotation suffix that will be used when the
106    annotation_level is 2. */
107 char *async_annotation_suffix;
108 
109 /* This is used to display the notification of the completion of an
110    asynchronous execution command. */
111 int exec_done_display_p = 0;
112 
113 /* This is the file descriptor for the input stream that GDB uses to
114    read commands from. */
115 int input_fd;
116 
117 /* This is the prompt stack. Prompts will be pushed on the stack as
118    needed by the different 'kinds' of user inputs GDB is asking
119    for. See event-loop.h. */
120 struct prompts the_prompts;
121 
122 /* signal handling variables */
123 /* Each of these is a pointer to a function that the event loop will
124    invoke if the corresponding signal has received. The real signal
125    handlers mark these functions as ready to be executed and the event
126    loop, in a later iteration, calls them. See the function
127    invoke_async_signal_handler. */
128 void *sigint_token;
129 #ifdef SIGHUP
130 void *sighup_token;
131 #endif
132 void *sigquit_token;
133 void *sigfpe_token;
134 #if defined(SIGWINCH) && defined(SIGWINCH_HANDLER)
135 void *sigwinch_token;
136 #endif
137 #ifdef STOP_SIGNAL
138 void *sigtstp_token;
139 #endif
140 
141 /* Structure to save a partially entered command.  This is used when
142    the user types '\' at the end of a command line. This is necessary
143    because each line of input is handled by a different call to
144    command_line_handler, and normally there is no state retained
145    between different calls. */
146 int more_to_come = 0;
147 
148 struct readline_input_state
149   {
150     char *linebuffer;
151     char *linebuffer_ptr;
152   }
153 readline_input_state;
154 
155 /* This hook is called by rl_callback_read_char_wrapper after each
156    character is processed.  */
157 void (*after_char_processing_hook) ();
158 
159 
160 /* Wrapper function for calling into the readline library. The event
161    loop expects the callback function to have a paramter, while readline
162    expects none. */
163 static void
rl_callback_read_char_wrapper(gdb_client_data client_data)164 rl_callback_read_char_wrapper (gdb_client_data client_data)
165 {
166   rl_callback_read_char ();
167   if (after_char_processing_hook)
168     (*after_char_processing_hook) ();
169 }
170 
171 /* Initialize all the necessary variables, start the event loop,
172    register readline, and stdin, start the loop. */
173 void
cli_command_loop(void)174 cli_command_loop (void)
175 {
176   int length;
177   char *a_prompt;
178   char *gdb_prompt = get_prompt ();
179 
180   /* If we are using readline, set things up and display the first
181      prompt, otherwise just print the prompt. */
182   if (async_command_editing_p)
183     {
184       /* Tell readline what the prompt to display is and what function it
185          will need to call after a whole line is read. This also displays
186          the first prompt. */
187       length = strlen (PREFIX (0)) + strlen (gdb_prompt) + strlen (SUFFIX (0)) + 1;
188       a_prompt = (char *) xmalloc (length);
189       strcpy (a_prompt, PREFIX (0));
190       strcat (a_prompt, gdb_prompt);
191       strcat (a_prompt, SUFFIX (0));
192       rl_callback_handler_install (a_prompt, input_handler);
193     }
194   else
195     display_gdb_prompt (0);
196 
197   /* Now it's time to start the event loop. */
198   start_event_loop ();
199 }
200 
201 /* Change the function to be invoked every time there is a character
202    ready on stdin. This is used when the user sets the editing off,
203    therefore bypassing readline, and letting gdb handle the input
204    itself, via gdb_readline2. Also it is used in the opposite case in
205    which the user sets editing on again, by restoring readline
206    handling of the input. */
207 static void
change_line_handler(void)208 change_line_handler (void)
209 {
210   /* NOTE: this operates on input_fd, not instream. If we are reading
211      commands from a file, instream will point to the file. However in
212      async mode, we always read commands from a file with editing
213      off. This means that the 'set editing on/off' will have effect
214      only on the interactive session. */
215 
216   if (async_command_editing_p)
217     {
218       /* Turn on editing by using readline. */
219       call_readline = rl_callback_read_char_wrapper;
220       input_handler = command_line_handler;
221     }
222   else
223     {
224       /* Turn off editing by using gdb_readline2. */
225       rl_callback_handler_remove ();
226       call_readline = gdb_readline2;
227 
228       /* Set up the command handler as well, in case we are called as
229          first thing from .gdbinit. */
230       input_handler = command_line_handler;
231     }
232 }
233 
234 /* Displays the prompt. The prompt that is displayed is the current
235    top of the prompt stack, if the argument NEW_PROMPT is
236    0. Otherwise, it displays whatever NEW_PROMPT is. This is used
237    after each gdb command has completed, and in the following cases:
238    1. when the user enters a command line which is ended by '\'
239    indicating that the command will continue on the next line.
240    In that case the prompt that is displayed is the empty string.
241    2. When the user is entering 'commands' for a breakpoint, or
242    actions for a tracepoint. In this case the prompt will be '>'
243    3. Other????
244    FIXME: 2. & 3. not implemented yet for async. */
245 void
display_gdb_prompt(char * new_prompt)246 display_gdb_prompt (char *new_prompt)
247 {
248   int prompt_length = 0;
249   char *gdb_prompt = get_prompt ();
250 
251   /* Each interpreter has its own rules on displaying the command
252      prompt.  */
253   if (!current_interp_display_prompt_p ())
254     return;
255 
256   if (target_executing && sync_execution)
257     {
258       /* This is to trick readline into not trying to display the
259          prompt.  Even though we display the prompt using this
260          function, readline still tries to do its own display if we
261          don't call rl_callback_handler_install and
262          rl_callback_handler_remove (which readline detects because a
263          global variable is not set). If readline did that, it could
264          mess up gdb signal handlers for SIGINT.  Readline assumes
265          that between calls to rl_set_signals and rl_clear_signals gdb
266          doesn't do anything with the signal handlers. Well, that's
267          not the case, because when the target executes we change the
268          SIGINT signal handler. If we allowed readline to display the
269          prompt, the signal handler change would happen exactly
270          between the calls to the above two functions.
271          Calling rl_callback_handler_remove(), does the job. */
272 
273       rl_callback_handler_remove ();
274       return;
275     }
276 
277   if (!new_prompt)
278     {
279       /* Just use the top of the prompt stack. */
280       prompt_length = strlen (PREFIX (0)) +
281 	strlen (SUFFIX (0)) +
282 	strlen (gdb_prompt) + 1;
283 
284       new_prompt = (char *) alloca (prompt_length);
285 
286       /* Prefix needs to have new line at end. */
287       strcpy (new_prompt, PREFIX (0));
288       strcat (new_prompt, gdb_prompt);
289       /* Suffix needs to have a new line at end and \032 \032 at
290          beginning. */
291       strcat (new_prompt, SUFFIX (0));
292     }
293 
294   if (async_command_editing_p)
295     {
296       rl_callback_handler_remove ();
297       rl_callback_handler_install (new_prompt, input_handler);
298     }
299   /* new_prompt at this point can be the top of the stack or the one passed in */
300   else if (new_prompt)
301     {
302       /* Don't use a _filtered function here.  It causes the assumed
303          character position to be off, since the newline we read from
304          the user is not accounted for.  */
305       fputs_unfiltered (new_prompt, gdb_stdout);
306       gdb_flush (gdb_stdout);
307     }
308 }
309 
310 /* Used when the user requests a different annotation level, with
311    'set annotate'. It pushes a new prompt (with prefix and suffix) on top
312    of the prompt stack, if the annotation level desired is 2, otherwise
313    it pops the top of the prompt stack when we want the annotation level
314    to be the normal ones (1 or 0). */
315 static void
change_annotation_level(void)316 change_annotation_level (void)
317 {
318   char *prefix, *suffix;
319 
320   if (!PREFIX (0) || !PROMPT (0) || !SUFFIX (0))
321     {
322       /* The prompt stack has not been initialized to "", we are
323          using gdb w/o the --async switch */
324       warning ("Command has same effect as set annotate");
325       return;
326     }
327 
328   if (annotation_level > 1)
329     {
330       if (!strcmp (PREFIX (0), "") && !strcmp (SUFFIX (0), ""))
331 	{
332 	  /* Push a new prompt if the previous annotation_level was not >1. */
333 	  prefix = (char *) alloca (strlen (async_annotation_suffix) + 10);
334 	  strcpy (prefix, "\n\032\032pre-");
335 	  strcat (prefix, async_annotation_suffix);
336 	  strcat (prefix, "\n");
337 
338 	  suffix = (char *) alloca (strlen (async_annotation_suffix) + 6);
339 	  strcpy (suffix, "\n\032\032");
340 	  strcat (suffix, async_annotation_suffix);
341 	  strcat (suffix, "\n");
342 
343 	  push_prompt (prefix, (char *) 0, suffix);
344 	}
345     }
346   else
347     {
348       if (strcmp (PREFIX (0), "") && strcmp (SUFFIX (0), ""))
349 	{
350 	  /* Pop the top of the stack, we are going back to annotation < 1. */
351 	  pop_prompt ();
352 	}
353     }
354 }
355 
356 /* Pushes a new prompt on the prompt stack. Each prompt has three
357    parts: prefix, prompt, suffix. Usually prefix and suffix are empty
358    strings, except when the annotation level is 2. Memory is allocated
359    within savestring for the new prompt. */
360 void
push_prompt(char * prefix,char * prompt,char * suffix)361 push_prompt (char *prefix, char *prompt, char *suffix)
362 {
363   the_prompts.top++;
364   PREFIX (0) = savestring (prefix, strlen (prefix));
365 
366   /* Note that this function is used by the set annotate 2
367      command. This is why we take care of saving the old prompt
368      in case a new one is not specified. */
369   if (prompt)
370     PROMPT (0) = savestring (prompt, strlen (prompt));
371   else
372     PROMPT (0) = savestring (PROMPT (-1), strlen (PROMPT (-1)));
373 
374   SUFFIX (0) = savestring (suffix, strlen (suffix));
375 }
376 
377 /* Pops the top of the prompt stack, and frees the memory allocated for it. */
378 void
pop_prompt(void)379 pop_prompt (void)
380 {
381   /* If we are not during a 'synchronous' execution command, in which
382      case, the top prompt would be empty. */
383   if (strcmp (PROMPT (0), ""))
384     /* This is for the case in which the prompt is set while the
385        annotation level is 2. The top prompt will be changed, but when
386        we return to annotation level < 2, we want that new prompt to be
387        in effect, until the user does another 'set prompt'. */
388     if (strcmp (PROMPT (0), PROMPT (-1)))
389       {
390 	xfree (PROMPT (-1));
391 	PROMPT (-1) = savestring (PROMPT (0), strlen (PROMPT (0)));
392       }
393 
394   xfree (PREFIX (0));
395   xfree (PROMPT (0));
396   xfree (SUFFIX (0));
397   the_prompts.top--;
398 }
399 
400 /* When there is an event ready on the stdin file desriptor, instead
401    of calling readline directly throught the callback function, or
402    instead of calling gdb_readline2, give gdb a chance to detect
403    errors and do something. */
404 void
stdin_event_handler(int error,gdb_client_data client_data)405 stdin_event_handler (int error, gdb_client_data client_data)
406 {
407   if (error)
408     {
409       printf_unfiltered ("error detected on stdin\n");
410       delete_file_handler (input_fd);
411       discard_all_continuations ();
412       /* If stdin died, we may as well kill gdb. */
413       quit_command ((char *) 0, stdin == instream);
414     }
415   else
416     (*call_readline) (client_data);
417 }
418 
419 /* Re-enable stdin after the end of an execution command in
420    synchronous mode, or after an error from the target, and we aborted
421    the exec operation. */
422 
423 void
async_enable_stdin(void * dummy)424 async_enable_stdin (void *dummy)
425 {
426   /* See NOTE in async_disable_stdin() */
427   /* FIXME: cagney/1999-09-27: Call this before clearing
428      sync_execution.  Current target_terminal_ours() implementations
429      check for sync_execution before switching the terminal. */
430   target_terminal_ours ();
431   pop_prompt ();
432   sync_execution = 0;
433 }
434 
435 /* Disable reads from stdin (the console) marking the command as
436    synchronous. */
437 
438 void
async_disable_stdin(void)439 async_disable_stdin (void)
440 {
441   sync_execution = 1;
442   push_prompt ("", "", "");
443   /* FIXME: cagney/1999-09-27: At present this call is technically
444      redundant since infcmd.c and infrun.c both already call
445      target_terminal_inferior().  As the terminal handling (in
446      sync/async mode) is refined, the duplicate calls can be
447      eliminated (Here or in infcmd.c/infrun.c). */
448   target_terminal_inferior ();
449   /* Add the reinstate of stdin to the list of cleanups to be done
450      in case the target errors out and dies. These cleanups are also
451      done in case of normal successful termination of the execution
452      command, by complete_execution(). */
453   make_exec_error_cleanup (async_enable_stdin, NULL);
454 }
455 
456 
457 /* Handles a gdb command. This function is called by
458    command_line_handler, which has processed one or more input lines
459    into COMMAND. */
460 /* NOTE: 1999-04-30 This is the asynchronous version of the command_loop
461    function.  The command_loop function will be obsolete when we
462    switch to use the event loop at every execution of gdb. */
463 static void
command_handler(char * command)464 command_handler (char *command)
465 {
466   struct cleanup *old_chain;
467   int stdin_is_tty = ISATTY (stdin);
468   struct continuation_arg *arg1;
469   struct continuation_arg *arg2;
470   long time_at_cmd_start;
471 #ifdef HAVE_SBRK
472   long space_at_cmd_start = 0;
473 #endif
474   extern int display_time;
475   extern int display_space;
476 
477   quit_flag = 0;
478   if (instream == stdin && stdin_is_tty)
479     reinitialize_more_filter ();
480   old_chain = make_cleanup (null_cleanup, 0);
481 
482   /* If readline returned a NULL command, it means that the
483      connection with the terminal is gone. This happens at the
484      end of a testsuite run, after Expect has hung up
485      but GDB is still alive. In such a case, we just quit gdb
486      killing the inferior program too. */
487   if (command == 0)
488     quit_command ((char *) 0, stdin == instream);
489 
490   time_at_cmd_start = get_run_time ();
491 
492   if (display_space)
493     {
494 #ifdef HAVE_SBRK
495       char *lim = (char *) sbrk (0);
496       space_at_cmd_start = lim - lim_at_start;
497 #endif
498     }
499 
500   execute_command (command, instream == stdin);
501 
502   /* Set things up for this function to be compete later, once the
503      execution has completed, if we are doing an execution command,
504      otherwise, just go ahead and finish. */
505   if (target_can_async_p () && target_executing)
506     {
507       arg1 =
508 	(struct continuation_arg *) xmalloc (sizeof (struct continuation_arg));
509       arg2 =
510 	(struct continuation_arg *) xmalloc (sizeof (struct continuation_arg));
511       arg1->next = arg2;
512       arg2->next = NULL;
513       arg1->data.longint = time_at_cmd_start;
514 #ifdef HAVE_SBRK
515       arg2->data.longint = space_at_cmd_start;
516 #endif
517       add_continuation (command_line_handler_continuation, arg1);
518     }
519 
520   /* Do any commands attached to breakpoint we stopped at. Only if we
521      are always running synchronously. Or if we have just executed a
522      command that doesn't start the target. */
523   if (!target_can_async_p () || !target_executing)
524     {
525       bpstat_do_actions (&stop_bpstat);
526       do_cleanups (old_chain);
527 
528       if (display_time)
529 	{
530 	  long cmd_time = get_run_time () - time_at_cmd_start;
531 
532 	  printf_unfiltered ("Command execution time: %ld.%06ld\n",
533 			     cmd_time / 1000000, cmd_time % 1000000);
534 	}
535 
536       if (display_space)
537 	{
538 #ifdef HAVE_SBRK
539 	  char *lim = (char *) sbrk (0);
540 	  long space_now = lim - lim_at_start;
541 	  long space_diff = space_now - space_at_cmd_start;
542 
543 	  printf_unfiltered ("Space used: %ld (%c%ld for this command)\n",
544 			     space_now,
545 			     (space_diff >= 0 ? '+' : '-'),
546 			     space_diff);
547 #endif
548 	}
549     }
550 }
551 
552 /* Do any commands attached to breakpoint we stopped at. Only if we
553    are always running synchronously. Or if we have just executed a
554    command that doesn't start the target. */
555 void
command_line_handler_continuation(struct continuation_arg * arg)556 command_line_handler_continuation (struct continuation_arg *arg)
557 {
558   extern int display_time;
559   extern int display_space;
560 
561   long time_at_cmd_start  = arg->data.longint;
562   long space_at_cmd_start = arg->next->data.longint;
563 
564   bpstat_do_actions (&stop_bpstat);
565   /*do_cleanups (old_chain); *//*?????FIXME????? */
566 
567   if (display_time)
568     {
569       long cmd_time = get_run_time () - time_at_cmd_start;
570 
571       printf_unfiltered ("Command execution time: %ld.%06ld\n",
572 			 cmd_time / 1000000, cmd_time % 1000000);
573     }
574   if (display_space)
575     {
576 #ifdef HAVE_SBRK
577       char *lim = (char *) sbrk (0);
578       long space_now = lim - lim_at_start;
579       long space_diff = space_now - space_at_cmd_start;
580 
581       printf_unfiltered ("Space used: %ld (%c%ld for this command)\n",
582 			 space_now,
583 			 (space_diff >= 0 ? '+' : '-'),
584 			 space_diff);
585 #endif
586     }
587 }
588 
589 /* Handle a complete line of input. This is called by the callback
590    mechanism within the readline library.  Deal with incomplete commands
591    as well, by saving the partial input in a global buffer.  */
592 
593 /* NOTE: 1999-04-30 This is the asynchronous version of the
594    command_line_input function. command_line_input will become
595    obsolete once we use the event loop as the default mechanism in
596    GDB. */
597 static void
command_line_handler(char * rl)598 command_line_handler (char *rl)
599 {
600   static char *linebuffer = 0;
601   static unsigned linelength = 0;
602   char *p;
603   char *p1;
604   extern char *line;
605   extern int linesize;
606   char *nline;
607   char got_eof = 0;
608 
609 
610   int repeat = (instream == stdin);
611 
612   if (annotation_level > 1 && instream == stdin)
613     {
614       printf_unfiltered ("\n\032\032post-");
615       puts_unfiltered (async_annotation_suffix);
616       printf_unfiltered ("\n");
617     }
618 
619   if (linebuffer == 0)
620     {
621       linelength = 80;
622       linebuffer = (char *) xmalloc (linelength);
623     }
624 
625   p = linebuffer;
626 
627   if (more_to_come)
628     {
629       strcpy (linebuffer, readline_input_state.linebuffer);
630       p = readline_input_state.linebuffer_ptr;
631       xfree (readline_input_state.linebuffer);
632       more_to_come = 0;
633       pop_prompt ();
634     }
635 
636 #ifdef STOP_SIGNAL
637   if (job_control)
638     signal (STOP_SIGNAL, handle_stop_sig);
639 #endif
640 
641   /* Make sure that all output has been output.  Some machines may let
642      you get away with leaving out some of the gdb_flush, but not all.  */
643   wrap_here ("");
644   gdb_flush (gdb_stdout);
645   gdb_flush (gdb_stderr);
646 
647   if (source_file_name != NULL)
648     {
649       ++source_line_number;
650       sprintf (source_error,
651 	       "%s%s:%d: Error in sourced command file:\n",
652 	       source_pre_error,
653 	       source_file_name,
654 	       source_line_number);
655       error_pre_print = source_error;
656     }
657 
658   /* If we are in this case, then command_handler will call quit
659      and exit from gdb. */
660   if (!rl || rl == (char *) EOF)
661     {
662       got_eof = 1;
663       command_handler (0);
664     }
665   if (strlen (rl) + 1 + (p - linebuffer) > linelength)
666     {
667       linelength = strlen (rl) + 1 + (p - linebuffer);
668       nline = (char *) xrealloc (linebuffer, linelength);
669       p += nline - linebuffer;
670       linebuffer = nline;
671     }
672   p1 = rl;
673   /* Copy line.  Don't copy null at end.  (Leaves line alone
674      if this was just a newline)  */
675   while (*p1)
676     *p++ = *p1++;
677 
678   xfree (rl);			/* Allocated in readline.  */
679 
680   if (p > linebuffer && *(p - 1) == '\\')
681     {
682       p--;			/* Put on top of '\'.  */
683 
684       readline_input_state.linebuffer = savestring (linebuffer,
685 						    strlen (linebuffer));
686       readline_input_state.linebuffer_ptr = p;
687 
688       /* We will not invoke a execute_command if there is more
689 	 input expected to complete the command. So, we need to
690 	 print an empty prompt here. */
691       more_to_come = 1;
692       push_prompt ("", "", "");
693       display_gdb_prompt (0);
694       return;
695     }
696 
697 #ifdef STOP_SIGNAL
698   if (job_control)
699     signal (STOP_SIGNAL, SIG_DFL);
700 #endif
701 
702 #define SERVER_COMMAND_LENGTH 7
703   server_command =
704     (p - linebuffer > SERVER_COMMAND_LENGTH)
705     && strncmp (linebuffer, "server ", SERVER_COMMAND_LENGTH) == 0;
706   if (server_command)
707     {
708       /* Note that we don't set `line'.  Between this and the check in
709          dont_repeat, this insures that repeating will still do the
710          right thing.  */
711       *p = '\0';
712       command_handler (linebuffer + SERVER_COMMAND_LENGTH);
713       display_gdb_prompt (0);
714       return;
715     }
716 
717   /* Do history expansion if that is wished.  */
718   if (history_expansion_p && instream == stdin
719       && ISATTY (instream))
720     {
721       char *history_value;
722       int expanded;
723 
724       *p = '\0';		/* Insert null now.  */
725       expanded = history_expand (linebuffer, &history_value);
726       if (expanded)
727 	{
728 	  /* Print the changes.  */
729 	  printf_unfiltered ("%s\n", history_value);
730 
731 	  /* If there was an error, call this function again.  */
732 	  if (expanded < 0)
733 	    {
734 	      xfree (history_value);
735 	      return;
736 	    }
737 	  if (strlen (history_value) > linelength)
738 	    {
739 	      linelength = strlen (history_value) + 1;
740 	      linebuffer = (char *) xrealloc (linebuffer, linelength);
741 	    }
742 	  strcpy (linebuffer, history_value);
743 	  p = linebuffer + strlen (linebuffer);
744 	  xfree (history_value);
745 	}
746     }
747 
748   /* If we just got an empty line, and that is supposed
749      to repeat the previous command, return the value in the
750      global buffer.  */
751   if (repeat && p == linebuffer && *p != '\\')
752     {
753       command_handler (line);
754       display_gdb_prompt (0);
755       return;
756     }
757 
758   for (p1 = linebuffer; *p1 == ' ' || *p1 == '\t'; p1++);
759   if (repeat && !*p1)
760     {
761       command_handler (line);
762       display_gdb_prompt (0);
763       return;
764     }
765 
766   *p = 0;
767 
768   /* Add line to history if appropriate.  */
769   if (instream == stdin
770       && ISATTY (stdin) && *linebuffer)
771     add_history (linebuffer);
772 
773   /* Note: lines consisting solely of comments are added to the command
774      history.  This is useful when you type a command, and then
775      realize you don't want to execute it quite yet.  You can comment
776      out the command and then later fetch it from the value history
777      and remove the '#'.  The kill ring is probably better, but some
778      people are in the habit of commenting things out.  */
779   if (*p1 == '#')
780     *p1 = '\0';			/* Found a comment. */
781 
782   /* Save into global buffer if appropriate.  */
783   if (repeat)
784     {
785       if (linelength > linesize)
786 	{
787 	  line = xrealloc (line, linelength);
788 	  linesize = linelength;
789 	}
790       strcpy (line, linebuffer);
791       if (!more_to_come)
792 	{
793 	  command_handler (line);
794 	  display_gdb_prompt (0);
795 	}
796       return;
797     }
798 
799   command_handler (linebuffer);
800   display_gdb_prompt (0);
801   return;
802 }
803 
804 /* Does reading of input from terminal w/o the editing features
805    provided by the readline library. */
806 
807 /* NOTE: 1999-04-30 Asynchronous version of gdb_readline. gdb_readline
808    will become obsolete when the event loop is made the default
809    execution for gdb. */
810 void
gdb_readline2(gdb_client_data client_data)811 gdb_readline2 (gdb_client_data client_data)
812 {
813   int c;
814   char *result;
815   int input_index = 0;
816   int result_size = 80;
817   static int done_once = 0;
818 
819   /* Unbuffer the input stream, so that, later on, the calls to fgetc
820      fetch only one char at the time from the stream. The fgetc's will
821      get up to the first newline, but there may be more chars in the
822      stream after '\n'. If we buffer the input and fgetc drains the
823      stream, getting stuff beyond the newline as well, a select, done
824      afterwards will not trigger. */
825   if (!done_once && !ISATTY (instream))
826     {
827       setbuf (instream, NULL);
828       done_once = 1;
829     }
830 
831   result = (char *) xmalloc (result_size);
832 
833   /* We still need the while loop here, even though it would seem
834      obvious to invoke gdb_readline2 at every character entered.  If
835      not using the readline library, the terminal is in cooked mode,
836      which sends the characters all at once. Poll will notice that the
837      input fd has changed state only after enter is pressed. At this
838      point we still need to fetch all the chars entered. */
839 
840   while (1)
841     {
842       /* Read from stdin if we are executing a user defined command.
843          This is the right thing for prompt_for_continue, at least.  */
844       c = fgetc (instream ? instream : stdin);
845 
846       if (c == EOF)
847 	{
848 	  if (input_index > 0)
849 	    /* The last line does not end with a newline.  Return it, and
850 	       if we are called again fgetc will still return EOF and
851 	       we'll return NULL then.  */
852 	    break;
853 	  xfree (result);
854 	  (*input_handler) (0);
855 	}
856 
857       if (c == '\n')
858 	{
859 	  if (input_index > 0 && result[input_index - 1] == '\r')
860 	    input_index--;
861 	  break;
862 	}
863 
864       result[input_index++] = c;
865       while (input_index >= result_size)
866 	{
867 	  result_size *= 2;
868 	  result = (char *) xrealloc (result, result_size);
869 	}
870     }
871 
872   result[input_index++] = '\0';
873   (*input_handler) (result);
874 }
875 
876 
877 /* Initialization of signal handlers and tokens.  There is a function
878    handle_sig* for each of the signals GDB cares about. Specifically:
879    SIGINT, SIGFPE, SIGQUIT, SIGTSTP, SIGHUP, SIGWINCH.  These
880    functions are the actual signal handlers associated to the signals
881    via calls to signal().  The only job for these functions is to
882    enqueue the appropriate event/procedure with the event loop.  Such
883    procedures are the old signal handlers. The event loop will take
884    care of invoking the queued procedures to perform the usual tasks
885    associated with the reception of the signal. */
886 /* NOTE: 1999-04-30 This is the asynchronous version of init_signals.
887    init_signals will become obsolete as we move to have to event loop
888    as the default for gdb. */
889 void
async_init_signals(void)890 async_init_signals (void)
891 {
892   signal (SIGINT, handle_sigint);
893   sigint_token =
894     create_async_signal_handler (async_request_quit, NULL);
895 
896   /* If SIGTRAP was set to SIG_IGN, then the SIG_IGN will get passed
897      to the inferior and breakpoints will be ignored.  */
898 #ifdef SIGTRAP
899   signal (SIGTRAP, SIG_DFL);
900 #endif
901 
902   /* If we initialize SIGQUIT to SIG_IGN, then the SIG_IGN will get
903      passed to the inferior, which we don't want.  It would be
904      possible to do a "signal (SIGQUIT, SIG_DFL)" after we fork, but
905      on BSD4.3 systems using vfork, that can affect the
906      GDB process as well as the inferior (the signal handling tables
907      might be in memory, shared between the two).  Since we establish
908      a handler for SIGQUIT, when we call exec it will set the signal
909      to SIG_DFL for us.  */
910   signal (SIGQUIT, handle_sigquit);
911   sigquit_token =
912     create_async_signal_handler (async_do_nothing, NULL);
913 #ifdef SIGHUP
914   if (signal (SIGHUP, handle_sighup) != SIG_IGN)
915     sighup_token =
916       create_async_signal_handler (async_disconnect, NULL);
917   else
918     sighup_token =
919       create_async_signal_handler (async_do_nothing, NULL);
920 #endif
921   signal (SIGFPE, handle_sigfpe);
922   sigfpe_token =
923     create_async_signal_handler (async_float_handler, NULL);
924 
925 #if defined(SIGWINCH) && defined(SIGWINCH_HANDLER)
926   signal (SIGWINCH, handle_sigwinch);
927   sigwinch_token =
928     create_async_signal_handler (SIGWINCH_HANDLER, NULL);
929 #endif
930 #ifdef STOP_SIGNAL
931   sigtstp_token =
932     create_async_signal_handler (async_stop_sig, NULL);
933 #endif
934 
935 }
936 
937 void
mark_async_signal_handler_wrapper(void * token)938 mark_async_signal_handler_wrapper (void *token)
939 {
940   mark_async_signal_handler ((struct async_signal_handler *) token);
941 }
942 
943 /* Tell the event loop what to do if SIGINT is received.
944    See event-signal.c. */
945 void
handle_sigint(int sig)946 handle_sigint (int sig)
947 {
948   signal (sig, handle_sigint);
949 
950   /* If immediate_quit is set, we go ahead and process the SIGINT right
951      away, even if we usually would defer this to the event loop. The
952      assumption here is that it is safe to process ^C immediately if
953      immediate_quit is set. If we didn't, SIGINT would be really
954      processed only the next time through the event loop.  To get to
955      that point, though, the command that we want to interrupt needs to
956      finish first, which is unacceptable. */
957   if (immediate_quit)
958     async_request_quit (0);
959   else
960     /* If immediate quit is not set, we process SIGINT the next time
961        through the loop, which is fine. */
962     mark_async_signal_handler_wrapper (sigint_token);
963 }
964 
965 /* Do the quit. All the checks have been done by the caller. */
966 void
async_request_quit(gdb_client_data arg)967 async_request_quit (gdb_client_data arg)
968 {
969   quit_flag = 1;
970   quit ();
971 }
972 
973 /* Tell the event loop what to do if SIGQUIT is received.
974    See event-signal.c. */
975 static void
handle_sigquit(int sig)976 handle_sigquit (int sig)
977 {
978   mark_async_signal_handler_wrapper (sigquit_token);
979   signal (sig, handle_sigquit);
980 }
981 
982 /* Called by the event loop in response to a SIGQUIT. */
983 static void
async_do_nothing(gdb_client_data arg)984 async_do_nothing (gdb_client_data arg)
985 {
986   /* Empty function body. */
987 }
988 
989 #ifdef SIGHUP
990 /* Tell the event loop what to do if SIGHUP is received.
991    See event-signal.c. */
992 static void
handle_sighup(int sig)993 handle_sighup (int sig)
994 {
995   mark_async_signal_handler_wrapper (sighup_token);
996   signal (sig, handle_sighup);
997 }
998 
999 /* Called by the event loop to process a SIGHUP */
1000 static void
async_disconnect(gdb_client_data arg)1001 async_disconnect (gdb_client_data arg)
1002 {
1003   catch_errors (quit_cover, NULL,
1004 		"Could not kill the program being debugged",
1005 		RETURN_MASK_ALL);
1006   signal (SIGHUP, SIG_DFL);	/*FIXME: ??????????? */
1007   kill (getpid (), SIGHUP);
1008 }
1009 #endif
1010 
1011 #ifdef STOP_SIGNAL
1012 void
handle_stop_sig(int sig)1013 handle_stop_sig (int sig)
1014 {
1015   mark_async_signal_handler_wrapper (sigtstp_token);
1016   signal (sig, handle_stop_sig);
1017 }
1018 
1019 static void
async_stop_sig(gdb_client_data arg)1020 async_stop_sig (gdb_client_data arg)
1021 {
1022   char *prompt = get_prompt ();
1023 #if STOP_SIGNAL == SIGTSTP
1024   signal (SIGTSTP, SIG_DFL);
1025 #if HAVE_SIGPROCMASK
1026   {
1027     sigset_t zero;
1028 
1029     sigemptyset (&zero);
1030     sigprocmask (SIG_SETMASK, &zero, 0);
1031   }
1032 #elif HAVE_SIGSETMASK
1033   sigsetmask (0);
1034 #endif
1035   kill (getpid (), SIGTSTP);
1036   signal (SIGTSTP, handle_stop_sig);
1037 #else
1038   signal (STOP_SIGNAL, handle_stop_sig);
1039 #endif
1040   printf_unfiltered ("%s", prompt);
1041   gdb_flush (gdb_stdout);
1042 
1043   /* Forget about any previous command -- null line now will do nothing.  */
1044   dont_repeat ();
1045 }
1046 #endif /* STOP_SIGNAL */
1047 
1048 /* Tell the event loop what to do if SIGFPE is received.
1049    See event-signal.c. */
1050 static void
handle_sigfpe(int sig)1051 handle_sigfpe (int sig)
1052 {
1053   mark_async_signal_handler_wrapper (sigfpe_token);
1054   signal (sig, handle_sigfpe);
1055 }
1056 
1057 /* Event loop will call this functin to process a SIGFPE. */
1058 static void
async_float_handler(gdb_client_data arg)1059 async_float_handler (gdb_client_data arg)
1060 {
1061   /* This message is based on ANSI C, section 4.7. Note that integer
1062      divide by zero causes this, so "float" is a misnomer. */
1063   error ("Erroneous arithmetic operation.");
1064 }
1065 
1066 /* Tell the event loop what to do if SIGWINCH is received.
1067    See event-signal.c. */
1068 #if defined(SIGWINCH) && defined(SIGWINCH_HANDLER)
1069 static void
handle_sigwinch(int sig)1070 handle_sigwinch (int sig)
1071 {
1072   mark_async_signal_handler_wrapper (sigwinch_token);
1073   signal (sig, handle_sigwinch);
1074 }
1075 #endif
1076 
1077 
1078 /* Called by do_setshow_command.  */
1079 void
set_async_editing_command(char * args,int from_tty,struct cmd_list_element * c)1080 set_async_editing_command (char *args, int from_tty, struct cmd_list_element *c)
1081 {
1082   change_line_handler ();
1083 }
1084 
1085 /* Called by do_setshow_command.  */
1086 void
set_async_annotation_level(char * args,int from_tty,struct cmd_list_element * c)1087 set_async_annotation_level (char *args, int from_tty, struct cmd_list_element *c)
1088 {
1089   change_annotation_level ();
1090 }
1091 
1092 /* Called by do_setshow_command.  */
1093 void
set_async_prompt(char * args,int from_tty,struct cmd_list_element * c)1094 set_async_prompt (char *args, int from_tty, struct cmd_list_element *c)
1095 {
1096   PROMPT (0) = savestring (new_async_prompt, strlen (new_async_prompt));
1097 }
1098 
1099 /* Set things up for readline to be invoked via the alternate
1100    interface, i.e. via a callback function (rl_callback_read_char),
1101    and hook up instream to the event loop. */
1102 void
gdb_setup_readline(void)1103 gdb_setup_readline (void)
1104 {
1105   /* This function is a noop for the sync case.  The assumption is
1106      that the sync setup is ALL done in gdb_init, and we would only
1107      mess it up here.  The sync stuff should really go away over
1108      time.  */
1109 
1110   gdb_stdout = stdio_fileopen (stdout);
1111   gdb_stderr = stdio_fileopen (stderr);
1112   gdb_stdlog = gdb_stderr;  /* for moment */
1113   gdb_stdtarg = gdb_stderr; /* for moment */
1114 
1115   /* If the input stream is connected to a terminal, turn on
1116      editing.  */
1117   if (ISATTY (instream))
1118     {
1119       /* Tell gdb that we will be using the readline library. This
1120 	 could be overwritten by a command in .gdbinit like 'set
1121 	 editing on' or 'off'.  */
1122       async_command_editing_p = 1;
1123 
1124       /* When a character is detected on instream by select or poll,
1125 	 readline will be invoked via this callback function.  */
1126       call_readline = rl_callback_read_char_wrapper;
1127     }
1128   else
1129     {
1130       async_command_editing_p = 0;
1131       call_readline = gdb_readline2;
1132     }
1133 
1134   /* When readline has read an end-of-line character, it passes the
1135      complete line to gdb for processing. command_line_handler is the
1136      function that does this.  */
1137   input_handler = command_line_handler;
1138 
1139   /* Tell readline to use the same input stream that gdb uses. */
1140   rl_instream = instream;
1141 
1142   /* Get a file descriptor for the input stream, so that we can
1143      register it with the event loop.  */
1144   input_fd = fileno (instream);
1145 
1146   /* Now we need to create the event sources for the input file
1147      descriptor.  */
1148   /* At this point in time, this is the only event source that we
1149      register with the even loop. Another source is going to be the
1150      target program (inferior), but that must be registered only when
1151      it actually exists (I.e. after we say 'run' or after we connect
1152      to a remote target.  */
1153   add_file_handler (input_fd, stdin_event_handler, 0);
1154 }
1155 
1156 /* Disable command input through the standard CLI channels.  Used in
1157    the suspend proc for interpreters that use the standard gdb readline
1158    interface, like the cli & the mi.  */
1159 void
gdb_disable_readline(void)1160 gdb_disable_readline (void)
1161 {
1162   /* FIXME - It is too heavyweight to delete and remake these every
1163      time you run an interpreter that needs readline.  It is probably
1164      better to have the interpreters cache these, which in turn means
1165      that this needs to be moved into interpreter specific code.  */
1166 
1167 #if 0
1168   ui_file_delete (gdb_stdout);
1169   ui_file_delete (gdb_stderr);
1170   gdb_stdlog = NULL;
1171   gdb_stdtarg = NULL;
1172 #endif
1173 
1174   rl_callback_handler_remove ();
1175   delete_file_handler (input_fd);
1176 }
1177