1 /* Top level stuff for GDB, the GNU debugger.
3 Copyright (C) 1999-2016 Free Software Foundation, Inc.
5 Written by Elena Zannoni <ezannoni@cygnus.com> of Cygnus Solutions.
7 This file is part of GDB.
9 This program is free software; you can redistribute it and/or modify
10 it under the terms of the GNU General Public License as published by
11 the Free Software Foundation; either version 3 of the License, or
12 (at your option) any later version.
14 This program is distributed in the hope that it will be useful,
15 but WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 GNU General Public License for more details.
19 You should have received a copy of the GNU General Public License
20 along with this program. If not, see <http://www.gnu.org/licenses/>. */
27 #include "terminal.h" /* for job_control */
28 #include "event-loop.h"
29 #include "event-top.h"
32 #include "cli/cli-script.h" /* for reset_command_nest_depth */
34 #include "gdbthread.h"
36 #include "continuations.h"
37 #include "gdbcmd.h" /* for dont_repeat() */
41 #include "ser-event.h"
42 #include "gdb_select.h"
44 /* readline include files. */
45 #include "readline/readline.h"
46 #include "readline/history.h"
48 /* readline defines this. */
51 static char *top_level_prompt (void);
53 /* Signal handlers. */
55 static void handle_sigquit (int sig);
58 static void handle_sighup (int sig);
60 static void handle_sigfpe (int sig);
62 /* Functions to be invoked by the event loop in response to
64 #if defined (SIGQUIT) || defined (SIGHUP)
65 static void async_do_nothing (gdb_client_data);
68 static void async_disconnect (gdb_client_data);
70 static void async_float_handler (gdb_client_data);
72 static void async_stop_sig (gdb_client_data);
74 static void async_sigterm_handler (gdb_client_data arg);
76 /* Instead of invoking (and waiting for) readline to read the command
77 line and pass it back for processing, we use readline's alternate
78 interface, via callback functions, so that the event loop can react
79 to other event sources while we wait for input. */
81 /* Important variables for the event loop. */
83 /* This is used to determine if GDB is using the readline library or
84 its own simplified form of readline. It is used by the asynchronous
85 form of the set editing command.
86 ezannoni: as of 1999-04-29 I expect that this
87 variable will not be used after gdb is changed to use the event
88 loop as default engine, and event-top.c is merged into top.c. */
89 int set_editing_cmd_var;
91 /* This is used to display the notification of the completion of an
92 asynchronous execution command. */
93 int exec_done_display_p = 0;
95 /* Used by the stdin event handler to compensate for missed stdin events.
96 Setting this to a non-zero value inside an stdin callback makes the callback
98 int call_stdin_event_handler_again_p;
100 /* Signal handling variables. */
101 /* Each of these is a pointer to a function that the event loop will
102 invoke if the corresponding signal has received. The real signal
103 handlers mark these functions as ready to be executed and the event
104 loop, in a later iteration, calls them. See the function
105 invoke_async_signal_handler. */
106 static struct async_signal_handler *sigint_token;
108 static struct async_signal_handler *sighup_token;
111 static struct async_signal_handler *sigquit_token;
113 static struct async_signal_handler *sigfpe_token;
115 static struct async_signal_handler *sigtstp_token;
117 static struct async_signal_handler *async_sigterm_token;
119 /* This hook is called by gdb_rl_callback_read_char_wrapper after each
120 character is processed. */
121 void (*after_char_processing_hook) (void);
124 /* Wrapper function for calling into the readline library. This takes
125 care of a couple things:
127 - The event loop expects the callback function to have a parameter,
128 while readline expects none.
130 - Propagation of GDB exceptions/errors thrown from INPUT_HANDLER
131 across readline requires special handling.
133 On the exceptions issue:
135 DWARF-based unwinding cannot cross code built without -fexceptions.
136 Any exception that tries to propagate through such code will fail
137 and the result is a call to std::terminate. While some ABIs, such
138 as x86-64, require all code to be built with exception tables,
141 This is a problem when GDB calls some non-EH-aware C library code,
142 that calls into GDB again through a callback, and that GDB callback
143 code throws a C++ exception. Turns out this is exactly what
144 happens with GDB's readline callback.
146 In such cases, we must catch and save any C++ exception that might
147 be thrown from the GDB callback before returning to the
148 non-EH-aware code. When the non-EH-aware function itself returns
149 back to GDB, we then rethrow the original C++ exception.
151 In the readline case however, the right thing to do is to longjmp
152 out of the callback, rather than do a normal return -- there's no
153 way for the callback to return to readline an indication that an
154 error happened, so a normal return would have rl_callback_read_char
155 potentially continue processing further input, redisplay the
156 prompt, etc. Instead of raw setjmp/longjmp however, we use our
157 sjlj-based TRY/CATCH mechanism, which knows to handle multiple
158 levels of active setjmp/longjmp frames, needed in order to handle
159 the readline callback recursing, as happens with e.g., secondary
160 prompts / queries, through gdb_readline_wrapper. */
163 gdb_rl_callback_read_char_wrapper (gdb_client_data client_data)
165 struct gdb_exception gdb_expt = exception_none;
167 /* C++ exceptions can't normally be thrown across readline (unless
168 it is built with -fexceptions, but it won't by default on many
169 ABIs). So we instead wrap the readline call with a sjlj-based
170 TRY/CATCH, and rethrow the GDB exception once back in GDB. */
173 rl_callback_read_char ();
174 if (after_char_processing_hook)
175 (*after_char_processing_hook) ();
177 CATCH_SJLJ (ex, RETURN_MASK_ALL)
183 /* Rethrow using the normal EH mechanism. */
184 if (gdb_expt.reason < 0)
185 throw_exception (gdb_expt);
188 /* GDB's readline callback handler. Calls the current INPUT_HANDLER,
189 and propagates GDB exceptions/errors thrown from INPUT_HANDLER back
190 across readline. See gdb_rl_callback_read_char_wrapper. */
193 gdb_rl_callback_handler (char *rl)
195 struct gdb_exception gdb_rl_expt = exception_none;
196 struct ui *ui = current_ui;
200 ui->input_handler (rl);
202 CATCH (ex, RETURN_MASK_ALL)
208 /* If we caught a GDB exception, longjmp out of the readline
209 callback. There's no other way for the callback to signal to
210 readline that an error happened. A normal return would have
211 readline potentially continue processing further input, redisplay
212 the prompt, etc. (This is what GDB historically did when it was
213 a C program.) Note that since we're long jumping, local variable
214 dtors are NOT run automatically. */
215 if (gdb_rl_expt.reason < 0)
216 throw_exception_sjlj (gdb_rl_expt);
219 /* Change the function to be invoked every time there is a character
220 ready on stdin. This is used when the user sets the editing off,
221 therefore bypassing readline, and letting gdb handle the input
222 itself, via gdb_readline_no_editing_callback. Also it is used in
223 the opposite case in which the user sets editing on again, by
224 restoring readline handling of the input.
226 NOTE: this operates on input_fd, not instream. If we are reading
227 commands from a file, instream will point to the file. However, we
228 always read commands from a file with editing off. This means that
229 the 'set editing on/off' will have effect only on the interactive
233 change_line_handler (int editing)
235 struct ui *ui = current_ui;
237 /* We can only have one instance of readline, so we only allow
238 editing on the main UI. */
242 /* Don't try enabling editing if the interpreter doesn't support it
244 if (!interp_supports_command_editing (top_level_interpreter ())
245 || !interp_supports_command_editing (command_interp ()))
250 gdb_assert (ui == main_ui);
252 /* Turn on editing by using readline. */
253 ui->call_readline = gdb_rl_callback_read_char_wrapper;
257 /* Turn off editing by using gdb_readline_no_editing_callback. */
258 if (ui->command_editing)
259 gdb_rl_callback_handler_remove ();
260 ui->call_readline = gdb_readline_no_editing_callback;
262 ui->command_editing = editing;
265 /* The functions below are wrappers for rl_callback_handler_remove and
266 rl_callback_handler_install that keep track of whether the callback
267 handler is installed in readline. This is necessary because after
268 handling a target event of a background execution command, we may
269 need to reinstall the callback handler if it was removed due to a
270 secondary prompt. See gdb_readline_wrapper_line. We don't
271 unconditionally install the handler for every target event because
272 that also clears the line buffer, thus installing it while the user
273 is typing would lose input. */
275 /* Whether we've registered a callback handler with readline. */
276 static int callback_handler_installed;
278 /* See event-top.h, and above. */
281 gdb_rl_callback_handler_remove (void)
283 gdb_assert (current_ui == main_ui);
285 rl_callback_handler_remove ();
286 callback_handler_installed = 0;
289 /* See event-top.h, and above. Note this wrapper doesn't have an
290 actual callback parameter because we always install
294 gdb_rl_callback_handler_install (const char *prompt)
296 gdb_assert (current_ui == main_ui);
298 /* Calling rl_callback_handler_install resets readline's input
299 buffer. Calling this when we were already processing input
300 therefore loses input. */
301 gdb_assert (!callback_handler_installed);
303 rl_callback_handler_install (prompt, gdb_rl_callback_handler);
304 callback_handler_installed = 1;
307 /* See event-top.h, and above. */
310 gdb_rl_callback_handler_reinstall (void)
312 gdb_assert (current_ui == main_ui);
314 if (!callback_handler_installed)
316 /* Passing NULL as prompt argument tells readline to not display
318 gdb_rl_callback_handler_install (NULL);
322 /* Displays the prompt. If the argument NEW_PROMPT is NULL, the
323 prompt that is displayed is the current top level prompt.
324 Otherwise, it displays whatever NEW_PROMPT is as a local/secondary
327 This is used after each gdb command has completed, and in the
330 1. When the user enters a command line which is ended by '\'
331 indicating that the command will continue on the next line. In
332 that case the prompt that is displayed is the empty string.
334 2. When the user is entering 'commands' for a breakpoint, or
335 actions for a tracepoint. In this case the prompt will be '>'
337 3. On prompting for pagination. */
340 display_gdb_prompt (const char *new_prompt)
342 char *actual_gdb_prompt = NULL;
343 struct cleanup *old_chain;
345 annotate_display_prompt ();
347 /* Reset the nesting depth used when trace-commands is set. */
348 reset_command_nest_depth ();
350 old_chain = make_cleanup (free_current_contents, &actual_gdb_prompt);
352 /* Do not call the python hook on an explicit prompt change as
353 passed to this function, as this forms a secondary/local prompt,
354 IE, displayed but not set. */
357 struct ui *ui = current_ui;
359 if (ui->prompt_state == PROMPTED)
360 internal_error (__FILE__, __LINE__, _("double prompt"));
361 else if (ui->prompt_state == PROMPT_BLOCKED)
363 /* This is to trick readline into not trying to display the
364 prompt. Even though we display the prompt using this
365 function, readline still tries to do its own display if
366 we don't call rl_callback_handler_install and
367 rl_callback_handler_remove (which readline detects
368 because a global variable is not set). If readline did
369 that, it could mess up gdb signal handlers for SIGINT.
370 Readline assumes that between calls to rl_set_signals and
371 rl_clear_signals gdb doesn't do anything with the signal
372 handlers. Well, that's not the case, because when the
373 target executes we change the SIGINT signal handler. If
374 we allowed readline to display the prompt, the signal
375 handler change would happen exactly between the calls to
376 the above two functions. Calling
377 rl_callback_handler_remove(), does the job. */
379 if (current_ui->command_editing)
380 gdb_rl_callback_handler_remove ();
381 do_cleanups (old_chain);
384 else if (ui->prompt_state == PROMPT_NEEDED)
386 /* Display the top level prompt. */
387 actual_gdb_prompt = top_level_prompt ();
388 ui->prompt_state = PROMPTED;
392 actual_gdb_prompt = xstrdup (new_prompt);
394 if (current_ui->command_editing)
396 gdb_rl_callback_handler_remove ();
397 gdb_rl_callback_handler_install (actual_gdb_prompt);
399 /* new_prompt at this point can be the top of the stack or the one
400 passed in. It can't be NULL. */
403 /* Don't use a _filtered function here. It causes the assumed
404 character position to be off, since the newline we read from
405 the user is not accounted for. */
406 fputs_unfiltered (actual_gdb_prompt, gdb_stdout);
407 gdb_flush (gdb_stdout);
410 do_cleanups (old_chain);
413 /* Return the top level prompt, as specified by "set prompt", possibly
414 overriden by the python gdb.prompt_hook hook, and then composed
415 with the prompt prefix and suffix (annotations). The caller is
416 responsible for freeing the returned string. */
419 top_level_prompt (void)
423 /* Give observers a chance of changing the prompt. E.g., the python
424 `gdb.prompt_hook' is installed as an observer. */
425 observer_notify_before_prompt (get_prompt ());
427 prompt = get_prompt ();
429 if (annotation_level >= 2)
431 /* Prefix needs to have new line at end. */
432 const char prefix[] = "\n\032\032pre-prompt\n";
434 /* Suffix needs to have a new line at end and \032 \032 at
436 const char suffix[] = "\n\032\032prompt\n";
438 return concat (prefix, prompt, suffix, (char *) NULL);
441 return xstrdup (prompt);
447 struct ui *current_ui;
453 restore_ui_cleanup (void *data)
455 current_ui = (struct ui *) data;
461 switch_thru_all_uis_init (struct switch_thru_all_uis *state)
463 state->iter = ui_list;
464 state->old_chain = make_cleanup (restore_ui_cleanup, current_ui);
470 switch_thru_all_uis_cond (struct switch_thru_all_uis *state)
472 if (state->iter != NULL)
474 current_ui = state->iter;
479 do_cleanups (state->old_chain);
487 switch_thru_all_uis_next (struct switch_thru_all_uis *state)
489 state->iter = state->iter->next;
492 /* Get a pointer to the current UI's line buffer. This is used to
493 construct a whole line of input from partial input. */
495 static struct buffer *
496 get_command_line_buffer (void)
498 return ¤t_ui->line_buffer;
501 /* When there is an event ready on the stdin file descriptor, instead
502 of calling readline directly throught the callback function, or
503 instead of calling gdb_readline_no_editing_callback, give gdb a
504 chance to detect errors and do something. */
507 stdin_event_handler (int error, gdb_client_data client_data)
509 struct ui *ui = (struct ui *) client_data;
513 /* Switch to the main UI, so diagnostics always go there. */
514 current_ui = main_ui;
516 delete_file_handler (ui->input_fd);
519 /* If stdin died, we may as well kill gdb. */
520 printf_unfiltered (_("error detected on stdin\n"));
521 quit_command ((char *) 0, 0);
525 /* Simply delete the UI. */
531 /* Switch to the UI whose input descriptor woke up the event
535 /* This makes sure a ^C immediately followed by further input is
536 always processed in that order. E.g,. with input like
537 "^Cprint 1\n", the SIGINT handler runs, marks the async
538 signal handler, and then select/poll may return with stdin
539 ready, instead of -1/EINTR. The
540 gdb.base/double-prompt-target-event-error.exp test exercises
546 call_stdin_event_handler_again_p = 0;
547 ui->call_readline (client_data);
549 while (call_stdin_event_handler_again_p != 0);
556 ui_register_input_event_handler (struct ui *ui)
558 add_file_handler (ui->input_fd, stdin_event_handler, ui);
564 ui_unregister_input_event_handler (struct ui *ui)
566 delete_file_handler (ui->input_fd);
569 /* Re-enable stdin after the end of an execution command in
570 synchronous mode, or after an error from the target, and we aborted
571 the exec operation. */
574 async_enable_stdin (void)
576 struct ui *ui = current_ui;
578 if (ui->prompt_state == PROMPT_BLOCKED)
580 target_terminal_ours ();
581 ui_register_input_event_handler (ui);
582 ui->prompt_state = PROMPT_NEEDED;
586 /* Disable reads from stdin (the console) marking the command as
590 async_disable_stdin (void)
592 struct ui *ui = current_ui;
594 ui->prompt_state = PROMPT_BLOCKED;
595 delete_file_handler (ui->input_fd);
599 /* Handle a gdb command line. This function is called when
600 handle_line_of_input has concatenated one or more input lines into
604 command_handler (char *command)
606 struct ui *ui = current_ui;
607 struct cleanup *stat_chain;
610 if (ui->instream == ui->stdin_stream)
611 reinitialize_more_filter ();
613 stat_chain = make_command_stats_cleanup (1);
615 /* Do not execute commented lines. */
616 for (c = command; *c == ' ' || *c == '\t'; c++)
620 execute_command (command, ui->instream == ui->stdin_stream);
622 /* Do any commands attached to breakpoint we stopped at. */
623 bpstat_do_actions ();
626 do_cleanups (stat_chain);
629 /* Append RL, an input line returned by readline or one of its
630 emulations, to CMD_LINE_BUFFER. Returns the command line if we
631 have a whole command line ready to be processed by the command
632 interpreter or NULL if the command line isn't complete yet (input
633 line ends in a backslash). Takes ownership of RL. */
636 command_line_append_input_line (struct buffer *cmd_line_buffer, char *rl)
643 if (len > 0 && rl[len - 1] == '\\')
645 /* Don't copy the backslash and wait for more. */
646 buffer_grow (cmd_line_buffer, rl, len - 1);
651 /* Copy whole line including terminating null, and we're
653 buffer_grow (cmd_line_buffer, rl, len + 1);
654 cmd = cmd_line_buffer->buffer;
657 /* Allocated in readline. */
663 /* Handle a line of input coming from readline.
665 If the read line ends with a continuation character (backslash),
666 save the partial input in CMD_LINE_BUFFER (except the backslash),
667 and return NULL. Otherwise, save the partial input and return a
668 pointer to CMD_LINE_BUFFER's buffer (null terminated), indicating a
669 whole command line is ready to be executed.
671 Returns EOF on end of file.
673 If REPEAT, handle command repetitions:
675 - If the input command line is NOT empty, the command returned is
676 copied into the global 'saved_command_line' var so that it can
679 - OTOH, if the input command line IS empty, return the previously
680 saved command instead of the empty input line.
684 handle_line_of_input (struct buffer *cmd_line_buffer,
685 char *rl, int repeat, char *annotation_suffix)
687 struct ui *ui = current_ui;
688 int from_tty = ui->instream == ui->stdin_stream;
695 cmd = command_line_append_input_line (cmd_line_buffer, rl);
699 /* We have a complete command line now. Prepare for the next
700 command, but leave ownership of memory to the buffer . */
701 cmd_line_buffer->used_size = 0;
703 if (from_tty && annotation_level > 1)
705 printf_unfiltered (("\n\032\032post-"));
706 puts_unfiltered (annotation_suffix);
707 printf_unfiltered (("\n"));
710 #define SERVER_COMMAND_PREFIX "server "
711 if (startswith (cmd, SERVER_COMMAND_PREFIX))
713 /* Note that we don't set `saved_command_line'. Between this
714 and the check in dont_repeat, this insures that repeating
715 will still do the right thing. */
716 return cmd + strlen (SERVER_COMMAND_PREFIX);
719 /* Do history expansion if that is wished. */
720 if (history_expansion_p && from_tty && input_interactive_p (current_ui))
725 expanded = history_expand (cmd, &history_value);
730 /* Print the changes. */
731 printf_unfiltered ("%s\n", history_value);
733 /* If there was an error, call this function again. */
736 xfree (history_value);
740 /* history_expand returns an allocated string. Just replace
741 our buffer with it. */
742 len = strlen (history_value);
743 xfree (buffer_finish (cmd_line_buffer));
744 cmd_line_buffer->buffer = history_value;
745 cmd_line_buffer->buffer_size = len + 1;
750 /* If we just got an empty line, and that is supposed to repeat the
751 previous command, return the previously saved command. */
752 for (p1 = cmd; *p1 == ' ' || *p1 == '\t'; p1++)
754 if (repeat && *p1 == '\0')
755 return saved_command_line;
757 /* Add command to history if appropriate. Note: lines consisting
758 solely of comments are also added to the command history. This
759 is useful when you type a command, and then realize you don't
760 want to execute it quite yet. You can comment out the command
761 and then later fetch it from the value history and remove the
762 '#'. The kill ring is probably better, but some people are in
763 the habit of commenting things out. */
764 if (*cmd != '\0' && from_tty && input_interactive_p (current_ui))
765 gdb_add_history (cmd);
767 /* Save into global buffer if appropriate. */
770 xfree (saved_command_line);
771 saved_command_line = xstrdup (cmd);
772 return saved_command_line;
778 /* Handle a complete line of input. This is called by the callback
779 mechanism within the readline library. Deal with incomplete
780 commands as well, by saving the partial input in a global
783 NOTE: This is the asynchronous version of the command_line_input
787 command_line_handler (char *rl)
789 struct buffer *line_buffer = get_command_line_buffer ();
790 struct ui *ui = current_ui;
793 cmd = handle_line_of_input (line_buffer, rl, 1, "prompt");
794 if (cmd == (char *) EOF)
796 /* stdin closed. The connection with the terminal is gone.
797 This happens at the end of a testsuite run, after Expect has
798 hung up but GDB is still alive. In such a case, we just quit
799 gdb killing the inferior program too. */
800 printf_unfiltered ("quit\n");
801 execute_command ("quit", 1);
803 else if (cmd == NULL)
805 /* We don't have a full line yet. Print an empty prompt. */
806 display_gdb_prompt ("");
810 ui->prompt_state = PROMPT_NEEDED;
812 command_handler (cmd);
814 if (ui->prompt_state != PROMPTED)
815 display_gdb_prompt (0);
819 /* Does reading of input from terminal w/o the editing features
820 provided by the readline library. Calls the line input handler
821 once we have a whole input line. */
824 gdb_readline_no_editing_callback (gdb_client_data client_data)
828 struct buffer line_buffer;
829 static int done_once = 0;
830 struct ui *ui = current_ui;
832 buffer_init (&line_buffer);
834 /* Unbuffer the input stream, so that, later on, the calls to fgetc
835 fetch only one char at the time from the stream. The fgetc's will
836 get up to the first newline, but there may be more chars in the
837 stream after '\n'. If we buffer the input and fgetc drains the
838 stream, getting stuff beyond the newline as well, a select, done
839 afterwards will not trigger. */
840 if (!done_once && !ISATTY (ui->instream))
842 setbuf (ui->instream, NULL);
846 /* We still need the while loop here, even though it would seem
847 obvious to invoke gdb_readline_no_editing_callback at every
848 character entered. If not using the readline library, the
849 terminal is in cooked mode, which sends the characters all at
850 once. Poll will notice that the input fd has changed state only
851 after enter is pressed. At this point we still need to fetch all
852 the chars entered. */
856 /* Read from stdin if we are executing a user defined command.
857 This is the right thing for prompt_for_continue, at least. */
858 c = fgetc (ui->instream != NULL ? ui->instream : ui->stdin_stream);
862 if (line_buffer.used_size > 0)
864 /* The last line does not end with a newline. Return it, and
865 if we are called again fgetc will still return EOF and
866 we'll return NULL then. */
869 xfree (buffer_finish (&line_buffer));
870 ui->input_handler (NULL);
876 if (line_buffer.used_size > 0
877 && line_buffer.buffer[line_buffer.used_size - 1] == '\r')
878 line_buffer.used_size--;
882 buffer_grow_char (&line_buffer, c);
885 buffer_grow_char (&line_buffer, '\0');
886 result = buffer_finish (&line_buffer);
887 ui->input_handler (result);
891 /* The serial event associated with the QUIT flag. set_quit_flag sets
892 this, and check_quit_flag clears it. Used by interruptible_select
893 to be able to do interruptible I/O with no race with the SIGINT
895 static struct serial_event *quit_serial_event;
897 /* Initialization of signal handlers and tokens. There is a function
898 handle_sig* for each of the signals GDB cares about. Specifically:
899 SIGINT, SIGFPE, SIGQUIT, SIGTSTP, SIGHUP, SIGWINCH. These
900 functions are the actual signal handlers associated to the signals
901 via calls to signal(). The only job for these functions is to
902 enqueue the appropriate event/procedure with the event loop. Such
903 procedures are the old signal handlers. The event loop will take
904 care of invoking the queued procedures to perform the usual tasks
905 associated with the reception of the signal. */
906 /* NOTE: 1999-04-30 This is the asynchronous version of init_signals.
907 init_signals will become obsolete as we move to have to event loop
908 as the default for gdb. */
910 async_init_signals (void)
912 initialize_async_signal_handlers ();
914 quit_serial_event = make_serial_event ();
916 signal (SIGINT, handle_sigint);
918 create_async_signal_handler (async_request_quit, NULL);
919 signal (SIGTERM, handle_sigterm);
921 = create_async_signal_handler (async_sigterm_handler, NULL);
923 /* If SIGTRAP was set to SIG_IGN, then the SIG_IGN will get passed
924 to the inferior and breakpoints will be ignored. */
926 signal (SIGTRAP, SIG_DFL);
930 /* If we initialize SIGQUIT to SIG_IGN, then the SIG_IGN will get
931 passed to the inferior, which we don't want. It would be
932 possible to do a "signal (SIGQUIT, SIG_DFL)" after we fork, but
933 on BSD4.3 systems using vfork, that can affect the
934 GDB process as well as the inferior (the signal handling tables
935 might be in memory, shared between the two). Since we establish
936 a handler for SIGQUIT, when we call exec it will set the signal
937 to SIG_DFL for us. */
938 signal (SIGQUIT, handle_sigquit);
940 create_async_signal_handler (async_do_nothing, NULL);
943 if (signal (SIGHUP, handle_sighup) != SIG_IGN)
945 create_async_signal_handler (async_disconnect, NULL);
948 create_async_signal_handler (async_do_nothing, NULL);
950 signal (SIGFPE, handle_sigfpe);
952 create_async_signal_handler (async_float_handler, NULL);
956 create_async_signal_handler (async_stop_sig, NULL);
963 quit_serial_event_set (void)
965 serial_event_set (quit_serial_event);
971 quit_serial_event_clear (void)
973 serial_event_clear (quit_serial_event);
976 /* Return the selectable file descriptor of the serial event
977 associated with the quit flag. */
980 quit_serial_event_fd (void)
982 return serial_event_fd (quit_serial_event);
988 default_quit_handler (void)
990 if (check_quit_flag ())
992 if (target_terminal_is_ours ())
995 target_pass_ctrlc ();
1000 quit_handler_ftype *quit_handler = default_quit_handler;
1002 /* Data for make_cleanup_override_quit_handler. Wrap the previous
1003 handler pointer in a data struct because it's not portable to cast
1004 a function pointer to a data pointer, which is what make_cleanup
1006 struct quit_handler_cleanup_data
1008 /* The previous quit handler. */
1009 quit_handler_ftype *prev_handler;
1012 /* Cleanup call that restores the previous quit handler. */
1015 restore_quit_handler (void *arg)
1017 struct quit_handler_cleanup_data *data
1018 = (struct quit_handler_cleanup_data *) arg;
1020 quit_handler = data->prev_handler;
1023 /* Destructor for the quit handler cleanup. */
1026 restore_quit_handler_dtor (void *arg)
1034 make_cleanup_override_quit_handler (quit_handler_ftype *new_quit_handler)
1036 struct cleanup *old_chain;
1037 struct quit_handler_cleanup_data *data;
1039 data = XNEW (struct quit_handler_cleanup_data);
1040 data->prev_handler = quit_handler;
1041 old_chain = make_cleanup_dtor (restore_quit_handler, data,
1042 restore_quit_handler_dtor);
1043 quit_handler = new_quit_handler;
1047 /* Handle a SIGINT. */
1050 handle_sigint (int sig)
1052 signal (sig, handle_sigint);
1054 /* We could be running in a loop reading in symfiles or something so
1055 it may be quite a while before we get back to the event loop. So
1056 set quit_flag to 1 here. Then if QUIT is called before we get to
1057 the event loop, we will unwind as expected. */
1060 /* In case nothing calls QUIT before the event loop is reached, the
1061 event loop handles it. */
1062 mark_async_signal_handler (sigint_token);
1065 /* See gdb_select.h. */
1068 interruptible_select (int n,
1069 fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
1070 struct timeval *timeout)
1076 if (readfds == NULL)
1078 readfds = &my_readfds;
1079 FD_ZERO (&my_readfds);
1082 fd = quit_serial_event_fd ();
1083 FD_SET (fd, readfds);
1089 res = gdb_select (n, readfds, writefds, exceptfds, timeout);
1091 while (res == -1 && errno == EINTR);
1093 if (res == 1 && FD_ISSET (fd, readfds))
1101 /* Handle GDB exit upon receiving SIGTERM if target_can_async_p (). */
1104 async_sigterm_handler (gdb_client_data arg)
1106 quit_force (NULL, 0);
1110 volatile int sync_quit_force_run;
1112 /* Quit GDB if SIGTERM is received.
1113 GDB would quit anyway, but this way it will clean up properly. */
1115 handle_sigterm (int sig)
1117 signal (sig, handle_sigterm);
1119 sync_quit_force_run = 1;
1122 mark_async_signal_handler (async_sigterm_token);
1125 /* Do the quit. All the checks have been done by the caller. */
1127 async_request_quit (gdb_client_data arg)
1129 /* If the quit_flag has gotten reset back to 0 by the time we get
1130 back here, that means that an exception was thrown to unwind the
1131 current command before we got back to the event loop. So there
1132 is no reason to call quit again here. */
1137 /* Tell the event loop what to do if SIGQUIT is received.
1138 See event-signal.c. */
1140 handle_sigquit (int sig)
1142 mark_async_signal_handler (sigquit_token);
1143 signal (sig, handle_sigquit);
1147 #if defined (SIGQUIT) || defined (SIGHUP)
1148 /* Called by the event loop in response to a SIGQUIT or an
1151 async_do_nothing (gdb_client_data arg)
1153 /* Empty function body. */
1158 /* Tell the event loop what to do if SIGHUP is received.
1159 See event-signal.c. */
1161 handle_sighup (int sig)
1163 mark_async_signal_handler (sighup_token);
1164 signal (sig, handle_sighup);
1167 /* Called by the event loop to process a SIGHUP. */
1169 async_disconnect (gdb_client_data arg)
1177 CATCH (exception, RETURN_MASK_ALL)
1179 fputs_filtered ("Could not kill the program being debugged",
1181 exception_print (gdb_stderr, exception);
1189 CATCH (exception, RETURN_MASK_ALL)
1194 signal (SIGHUP, SIG_DFL); /*FIXME: ??????????? */
1201 handle_stop_sig (int sig)
1203 mark_async_signal_handler (sigtstp_token);
1204 signal (sig, handle_stop_sig);
1208 async_stop_sig (gdb_client_data arg)
1210 char *prompt = get_prompt ();
1212 #if STOP_SIGNAL == SIGTSTP
1213 signal (SIGTSTP, SIG_DFL);
1214 #if HAVE_SIGPROCMASK
1218 sigemptyset (&zero);
1219 sigprocmask (SIG_SETMASK, &zero, 0);
1221 #elif HAVE_SIGSETMASK
1225 signal (SIGTSTP, handle_stop_sig);
1227 signal (STOP_SIGNAL, handle_stop_sig);
1229 printf_unfiltered ("%s", prompt);
1230 gdb_flush (gdb_stdout);
1232 /* Forget about any previous command -- null line now will do
1236 #endif /* STOP_SIGNAL */
1238 /* Tell the event loop what to do if SIGFPE is received.
1239 See event-signal.c. */
1241 handle_sigfpe (int sig)
1243 mark_async_signal_handler (sigfpe_token);
1244 signal (sig, handle_sigfpe);
1247 /* Event loop will call this functin to process a SIGFPE. */
1249 async_float_handler (gdb_client_data arg)
1251 /* This message is based on ANSI C, section 4.7. Note that integer
1252 divide by zero causes this, so "float" is a misnomer. */
1253 error (_("Erroneous arithmetic operation."));
1257 /* Set things up for readline to be invoked via the alternate
1258 interface, i.e. via a callback function
1259 (gdb_rl_callback_read_char), and hook up instream to the event
1263 gdb_setup_readline (int editing)
1265 struct ui *ui = current_ui;
1267 /* This function is a noop for the sync case. The assumption is
1268 that the sync setup is ALL done in gdb_init, and we would only
1269 mess it up here. The sync stuff should really go away over
1272 gdb_stdout = stdio_fileopen (ui->outstream);
1273 gdb_stderr = stderr_fileopen (ui->errstream);
1274 gdb_stdlog = gdb_stderr; /* for moment */
1275 gdb_stdtarg = gdb_stderr; /* for moment */
1276 gdb_stdtargerr = gdb_stderr; /* for moment */
1278 /* If the input stream is connected to a terminal, turn on editing.
1279 However, that is only allowed on the main UI, as we can only have
1280 one instance of readline. */
1281 if (ISATTY (ui->instream) && editing && ui == main_ui)
1283 /* Tell gdb that we will be using the readline library. This
1284 could be overwritten by a command in .gdbinit like 'set
1285 editing on' or 'off'. */
1286 ui->command_editing = 1;
1288 /* When a character is detected on instream by select or poll,
1289 readline will be invoked via this callback function. */
1290 ui->call_readline = gdb_rl_callback_read_char_wrapper;
1292 /* Tell readline to use the same input stream that gdb uses. */
1293 rl_instream = ui->instream;
1297 ui->command_editing = 0;
1298 ui->call_readline = gdb_readline_no_editing_callback;
1301 /* Now create the event source for this UI's input file descriptor.
1302 Another source is going to be the target program (inferior), but
1303 that must be registered only when it actually exists (I.e. after
1304 we say 'run' or after we connect to a remote target. */
1305 ui_register_input_event_handler (ui);
1308 /* Disable command input through the standard CLI channels. Used in
1309 the suspend proc for interpreters that use the standard gdb readline
1310 interface, like the cli & the mi. */
1313 gdb_disable_readline (void)
1315 struct ui *ui = current_ui;
1317 /* FIXME - It is too heavyweight to delete and remake these every
1318 time you run an interpreter that needs readline. It is probably
1319 better to have the interpreters cache these, which in turn means
1320 that this needs to be moved into interpreter specific code. */
1323 ui_file_delete (gdb_stdout);
1324 ui_file_delete (gdb_stderr);
1327 gdb_stdtargerr = NULL;
1330 if (ui->command_editing)
1331 gdb_rl_callback_handler_remove ();
1332 delete_file_handler (ui->input_fd);