1 /* Top level stuff for GDB, the GNU debugger.
3 Copyright (C) 1999-2018 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"
35 #include "observable.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 std::string top_level_prompt ();
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_sigtstp_handler (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. This must be
161 noexcept in order to avoid problems with mixing sjlj and
162 (sjlj-based) C++ exceptions. */
164 static struct gdb_exception
165 gdb_rl_callback_read_char_wrapper_noexcept () noexcept
167 struct gdb_exception gdb_expt = exception_none;
169 /* C++ exceptions can't normally be thrown across readline (unless
170 it is built with -fexceptions, but it won't by default on many
171 ABIs). So we instead wrap the readline call with a sjlj-based
172 TRY/CATCH, and rethrow the GDB exception once back in GDB. */
175 rl_callback_read_char ();
176 if (after_char_processing_hook)
177 (*after_char_processing_hook) ();
179 CATCH_SJLJ (ex, RETURN_MASK_ALL)
189 gdb_rl_callback_read_char_wrapper (gdb_client_data client_data)
191 struct gdb_exception gdb_expt
192 = gdb_rl_callback_read_char_wrapper_noexcept ();
194 /* Rethrow using the normal EH mechanism. */
195 if (gdb_expt.reason < 0)
196 throw_exception (gdb_expt);
199 /* GDB's readline callback handler. Calls the current INPUT_HANDLER,
200 and propagates GDB exceptions/errors thrown from INPUT_HANDLER back
201 across readline. See gdb_rl_callback_read_char_wrapper. This must
202 be noexcept in order to avoid problems with mixing sjlj and
203 (sjlj-based) C++ exceptions. */
206 gdb_rl_callback_handler (char *rl) noexcept
208 struct gdb_exception gdb_rl_expt = exception_none;
209 struct ui *ui = current_ui;
213 ui->input_handler (gdb::unique_xmalloc_ptr<char> (rl));
215 CATCH (ex, RETURN_MASK_ALL)
221 /* If we caught a GDB exception, longjmp out of the readline
222 callback. There's no other way for the callback to signal to
223 readline that an error happened. A normal return would have
224 readline potentially continue processing further input, redisplay
225 the prompt, etc. (This is what GDB historically did when it was
226 a C program.) Note that since we're long jumping, local variable
227 dtors are NOT run automatically. */
228 if (gdb_rl_expt.reason < 0)
229 throw_exception_sjlj (gdb_rl_expt);
232 /* Change the function to be invoked every time there is a character
233 ready on stdin. This is used when the user sets the editing off,
234 therefore bypassing readline, and letting gdb handle the input
235 itself, via gdb_readline_no_editing_callback. Also it is used in
236 the opposite case in which the user sets editing on again, by
237 restoring readline handling of the input.
239 NOTE: this operates on input_fd, not instream. If we are reading
240 commands from a file, instream will point to the file. However, we
241 always read commands from a file with editing off. This means that
242 the 'set editing on/off' will have effect only on the interactive
246 change_line_handler (int editing)
248 struct ui *ui = current_ui;
250 /* We can only have one instance of readline, so we only allow
251 editing on the main UI. */
255 /* Don't try enabling editing if the interpreter doesn't support it
257 if (!interp_supports_command_editing (top_level_interpreter ())
258 || !interp_supports_command_editing (command_interp ()))
263 gdb_assert (ui == main_ui);
265 /* Turn on editing by using readline. */
266 ui->call_readline = gdb_rl_callback_read_char_wrapper;
270 /* Turn off editing by using gdb_readline_no_editing_callback. */
271 if (ui->command_editing)
272 gdb_rl_callback_handler_remove ();
273 ui->call_readline = gdb_readline_no_editing_callback;
275 ui->command_editing = editing;
278 /* The functions below are wrappers for rl_callback_handler_remove and
279 rl_callback_handler_install that keep track of whether the callback
280 handler is installed in readline. This is necessary because after
281 handling a target event of a background execution command, we may
282 need to reinstall the callback handler if it was removed due to a
283 secondary prompt. See gdb_readline_wrapper_line. We don't
284 unconditionally install the handler for every target event because
285 that also clears the line buffer, thus installing it while the user
286 is typing would lose input. */
288 /* Whether we've registered a callback handler with readline. */
289 static int callback_handler_installed;
291 /* See event-top.h, and above. */
294 gdb_rl_callback_handler_remove (void)
296 gdb_assert (current_ui == main_ui);
298 rl_callback_handler_remove ();
299 callback_handler_installed = 0;
302 /* See event-top.h, and above. Note this wrapper doesn't have an
303 actual callback parameter because we always install
307 gdb_rl_callback_handler_install (const char *prompt)
309 gdb_assert (current_ui == main_ui);
311 /* Calling rl_callback_handler_install resets readline's input
312 buffer. Calling this when we were already processing input
313 therefore loses input. */
314 gdb_assert (!callback_handler_installed);
316 rl_callback_handler_install (prompt, gdb_rl_callback_handler);
317 callback_handler_installed = 1;
320 /* See event-top.h, and above. */
323 gdb_rl_callback_handler_reinstall (void)
325 gdb_assert (current_ui == main_ui);
327 if (!callback_handler_installed)
329 /* Passing NULL as prompt argument tells readline to not display
331 gdb_rl_callback_handler_install (NULL);
335 /* Displays the prompt. If the argument NEW_PROMPT is NULL, the
336 prompt that is displayed is the current top level prompt.
337 Otherwise, it displays whatever NEW_PROMPT is as a local/secondary
340 This is used after each gdb command has completed, and in the
343 1. When the user enters a command line which is ended by '\'
344 indicating that the command will continue on the next line. In
345 that case the prompt that is displayed is the empty string.
347 2. When the user is entering 'commands' for a breakpoint, or
348 actions for a tracepoint. In this case the prompt will be '>'
350 3. On prompting for pagination. */
353 display_gdb_prompt (const char *new_prompt)
355 std::string actual_gdb_prompt;
357 annotate_display_prompt ();
359 /* Reset the nesting depth used when trace-commands is set. */
360 reset_command_nest_depth ();
362 /* Do not call the python hook on an explicit prompt change as
363 passed to this function, as this forms a secondary/local prompt,
364 IE, displayed but not set. */
367 struct ui *ui = current_ui;
369 if (ui->prompt_state == PROMPTED)
370 internal_error (__FILE__, __LINE__, _("double prompt"));
371 else if (ui->prompt_state == PROMPT_BLOCKED)
373 /* This is to trick readline into not trying to display the
374 prompt. Even though we display the prompt using this
375 function, readline still tries to do its own display if
376 we don't call rl_callback_handler_install and
377 rl_callback_handler_remove (which readline detects
378 because a global variable is not set). If readline did
379 that, it could mess up gdb signal handlers for SIGINT.
380 Readline assumes that between calls to rl_set_signals and
381 rl_clear_signals gdb doesn't do anything with the signal
382 handlers. Well, that's not the case, because when the
383 target executes we change the SIGINT signal handler. If
384 we allowed readline to display the prompt, the signal
385 handler change would happen exactly between the calls to
386 the above two functions. Calling
387 rl_callback_handler_remove(), does the job. */
389 if (current_ui->command_editing)
390 gdb_rl_callback_handler_remove ();
393 else if (ui->prompt_state == PROMPT_NEEDED)
395 /* Display the top level prompt. */
396 actual_gdb_prompt = top_level_prompt ();
397 ui->prompt_state = PROMPTED;
401 actual_gdb_prompt = new_prompt;
403 if (current_ui->command_editing)
405 gdb_rl_callback_handler_remove ();
406 gdb_rl_callback_handler_install (actual_gdb_prompt.c_str ());
408 /* new_prompt at this point can be the top of the stack or the one
409 passed in. It can't be NULL. */
412 /* Don't use a _filtered function here. It causes the assumed
413 character position to be off, since the newline we read from
414 the user is not accounted for. */
415 fputs_unfiltered (actual_gdb_prompt.c_str (), gdb_stdout);
416 gdb_flush (gdb_stdout);
420 /* Return the top level prompt, as specified by "set prompt", possibly
421 overriden by the python gdb.prompt_hook hook, and then composed
422 with the prompt prefix and suffix (annotations). */
425 top_level_prompt (void)
429 /* Give observers a chance of changing the prompt. E.g., the python
430 `gdb.prompt_hook' is installed as an observer. */
431 gdb::observers::before_prompt.notify (get_prompt ());
433 prompt = get_prompt ();
435 if (annotation_level >= 2)
437 /* Prefix needs to have new line at end. */
438 const char prefix[] = "\n\032\032pre-prompt\n";
440 /* Suffix needs to have a new line at end and \032 \032 at
442 const char suffix[] = "\n\032\032prompt\n";
444 return std::string (prefix) + prompt + suffix;
453 struct ui *current_ui;
456 /* Get a pointer to the current UI's line buffer. This is used to
457 construct a whole line of input from partial input. */
459 static struct buffer *
460 get_command_line_buffer (void)
462 return ¤t_ui->line_buffer;
465 /* When there is an event ready on the stdin file descriptor, instead
466 of calling readline directly throught the callback function, or
467 instead of calling gdb_readline_no_editing_callback, give gdb a
468 chance to detect errors and do something. */
471 stdin_event_handler (int error, gdb_client_data client_data)
473 struct ui *ui = (struct ui *) client_data;
477 /* Switch to the main UI, so diagnostics always go there. */
478 current_ui = main_ui;
480 delete_file_handler (ui->input_fd);
483 /* If stdin died, we may as well kill gdb. */
484 printf_unfiltered (_("error detected on stdin\n"));
485 quit_command ((char *) 0, 0);
489 /* Simply delete the UI. */
495 /* Switch to the UI whose input descriptor woke up the event
499 /* This makes sure a ^C immediately followed by further input is
500 always processed in that order. E.g,. with input like
501 "^Cprint 1\n", the SIGINT handler runs, marks the async
502 signal handler, and then select/poll may return with stdin
503 ready, instead of -1/EINTR. The
504 gdb.base/double-prompt-target-event-error.exp test exercises
510 call_stdin_event_handler_again_p = 0;
511 ui->call_readline (client_data);
513 while (call_stdin_event_handler_again_p != 0);
520 ui_register_input_event_handler (struct ui *ui)
522 add_file_handler (ui->input_fd, stdin_event_handler, ui);
528 ui_unregister_input_event_handler (struct ui *ui)
530 delete_file_handler (ui->input_fd);
533 /* Re-enable stdin after the end of an execution command in
534 synchronous mode, or after an error from the target, and we aborted
535 the exec operation. */
538 async_enable_stdin (void)
540 struct ui *ui = current_ui;
542 if (ui->prompt_state == PROMPT_BLOCKED)
544 target_terminal::ours ();
545 ui_register_input_event_handler (ui);
546 ui->prompt_state = PROMPT_NEEDED;
550 /* Disable reads from stdin (the console) marking the command as
554 async_disable_stdin (void)
556 struct ui *ui = current_ui;
558 ui->prompt_state = PROMPT_BLOCKED;
559 delete_file_handler (ui->input_fd);
563 /* Handle a gdb command line. This function is called when
564 handle_line_of_input has concatenated one or more input lines into
568 command_handler (const char *command)
570 struct ui *ui = current_ui;
573 if (ui->instream == ui->stdin_stream)
574 reinitialize_more_filter ();
576 scoped_command_stats stat_reporter (true);
578 /* Do not execute commented lines. */
579 for (c = command; *c == ' ' || *c == '\t'; c++)
583 execute_command (command, ui->instream == ui->stdin_stream);
585 /* Do any commands attached to breakpoint we stopped at. */
586 bpstat_do_actions ();
590 /* Append RL, an input line returned by readline or one of its
591 emulations, to CMD_LINE_BUFFER. Returns the command line if we
592 have a whole command line ready to be processed by the command
593 interpreter or NULL if the command line isn't complete yet (input
594 line ends in a backslash). */
597 command_line_append_input_line (struct buffer *cmd_line_buffer, const char *rl)
604 if (len > 0 && rl[len - 1] == '\\')
606 /* Don't copy the backslash and wait for more. */
607 buffer_grow (cmd_line_buffer, rl, len - 1);
612 /* Copy whole line including terminating null, and we're
614 buffer_grow (cmd_line_buffer, rl, len + 1);
615 cmd = cmd_line_buffer->buffer;
621 /* Handle a line of input coming from readline.
623 If the read line ends with a continuation character (backslash),
624 save the partial input in CMD_LINE_BUFFER (except the backslash),
625 and return NULL. Otherwise, save the partial input and return a
626 pointer to CMD_LINE_BUFFER's buffer (null terminated), indicating a
627 whole command line is ready to be executed.
629 Returns EOF on end of file.
631 If REPEAT, handle command repetitions:
633 - If the input command line is NOT empty, the command returned is
634 copied into the global 'saved_command_line' var so that it can
637 - OTOH, if the input command line IS empty, return the previously
638 saved command instead of the empty input line.
642 handle_line_of_input (struct buffer *cmd_line_buffer,
643 const char *rl, int repeat,
644 const char *annotation_suffix)
646 struct ui *ui = current_ui;
647 int from_tty = ui->instream == ui->stdin_stream;
654 cmd = command_line_append_input_line (cmd_line_buffer, rl);
658 /* We have a complete command line now. Prepare for the next
659 command, but leave ownership of memory to the buffer . */
660 cmd_line_buffer->used_size = 0;
662 if (from_tty && annotation_level > 1)
664 printf_unfiltered (("\n\032\032post-"));
665 puts_unfiltered (annotation_suffix);
666 printf_unfiltered (("\n"));
669 #define SERVER_COMMAND_PREFIX "server "
670 server_command = startswith (cmd, SERVER_COMMAND_PREFIX);
673 /* Note that we don't set `saved_command_line'. Between this
674 and the check in dont_repeat, this insures that repeating
675 will still do the right thing. */
676 return cmd + strlen (SERVER_COMMAND_PREFIX);
679 /* Do history expansion if that is wished. */
680 if (history_expansion_p && from_tty && input_interactive_p (current_ui))
685 expanded = history_expand (cmd, &history_value);
690 /* Print the changes. */
691 printf_unfiltered ("%s\n", history_value);
693 /* If there was an error, call this function again. */
696 xfree (history_value);
700 /* history_expand returns an allocated string. Just replace
701 our buffer with it. */
702 len = strlen (history_value);
703 xfree (buffer_finish (cmd_line_buffer));
704 cmd_line_buffer->buffer = history_value;
705 cmd_line_buffer->buffer_size = len + 1;
710 /* If we just got an empty line, and that is supposed to repeat the
711 previous command, return the previously saved command. */
712 for (p1 = cmd; *p1 == ' ' || *p1 == '\t'; p1++)
714 if (repeat && *p1 == '\0')
715 return saved_command_line;
717 /* Add command to history if appropriate. Note: lines consisting
718 solely of comments are also added to the command history. This
719 is useful when you type a command, and then realize you don't
720 want to execute it quite yet. You can comment out the command
721 and then later fetch it from the value history and remove the
722 '#'. The kill ring is probably better, but some people are in
723 the habit of commenting things out. */
724 if (*cmd != '\0' && from_tty && input_interactive_p (current_ui))
725 gdb_add_history (cmd);
727 /* Save into global buffer if appropriate. */
730 xfree (saved_command_line);
731 saved_command_line = xstrdup (cmd);
732 return saved_command_line;
738 /* Handle a complete line of input. This is called by the callback
739 mechanism within the readline library. Deal with incomplete
740 commands as well, by saving the partial input in a global
743 NOTE: This is the asynchronous version of the command_line_input
747 command_line_handler (gdb::unique_xmalloc_ptr<char> &&rl)
749 struct buffer *line_buffer = get_command_line_buffer ();
750 struct ui *ui = current_ui;
753 cmd = handle_line_of_input (line_buffer, rl.get (), 1, "prompt");
754 if (cmd == (char *) EOF)
756 /* stdin closed. The connection with the terminal is gone.
757 This happens at the end of a testsuite run, after Expect has
758 hung up but GDB is still alive. In such a case, we just quit
759 gdb killing the inferior program too. */
760 printf_unfiltered ("quit\n");
761 execute_command ("quit", 1);
763 else if (cmd == NULL)
765 /* We don't have a full line yet. Print an empty prompt. */
766 display_gdb_prompt ("");
770 ui->prompt_state = PROMPT_NEEDED;
772 command_handler (cmd);
774 if (ui->prompt_state != PROMPTED)
775 display_gdb_prompt (0);
779 /* Does reading of input from terminal w/o the editing features
780 provided by the readline library. Calls the line input handler
781 once we have a whole input line. */
784 gdb_readline_no_editing_callback (gdb_client_data client_data)
788 struct buffer line_buffer;
789 static int done_once = 0;
790 struct ui *ui = current_ui;
792 buffer_init (&line_buffer);
794 /* Unbuffer the input stream, so that, later on, the calls to fgetc
795 fetch only one char at the time from the stream. The fgetc's will
796 get up to the first newline, but there may be more chars in the
797 stream after '\n'. If we buffer the input and fgetc drains the
798 stream, getting stuff beyond the newline as well, a select, done
799 afterwards will not trigger. */
800 if (!done_once && !ISATTY (ui->instream))
802 setbuf (ui->instream, NULL);
806 /* We still need the while loop here, even though it would seem
807 obvious to invoke gdb_readline_no_editing_callback at every
808 character entered. If not using the readline library, the
809 terminal is in cooked mode, which sends the characters all at
810 once. Poll will notice that the input fd has changed state only
811 after enter is pressed. At this point we still need to fetch all
812 the chars entered. */
816 /* Read from stdin if we are executing a user defined command.
817 This is the right thing for prompt_for_continue, at least. */
818 c = fgetc (ui->instream != NULL ? ui->instream : ui->stdin_stream);
822 if (line_buffer.used_size > 0)
824 /* The last line does not end with a newline. Return it, and
825 if we are called again fgetc will still return EOF and
826 we'll return NULL then. */
829 xfree (buffer_finish (&line_buffer));
830 ui->input_handler (NULL);
836 if (line_buffer.used_size > 0
837 && line_buffer.buffer[line_buffer.used_size - 1] == '\r')
838 line_buffer.used_size--;
842 buffer_grow_char (&line_buffer, c);
845 buffer_grow_char (&line_buffer, '\0');
846 result = buffer_finish (&line_buffer);
847 ui->input_handler (gdb::unique_xmalloc_ptr<char> (result));
851 /* The serial event associated with the QUIT flag. set_quit_flag sets
852 this, and check_quit_flag clears it. Used by interruptible_select
853 to be able to do interruptible I/O with no race with the SIGINT
855 static struct serial_event *quit_serial_event;
857 /* Initialization of signal handlers and tokens. There is a function
858 handle_sig* for each of the signals GDB cares about. Specifically:
859 SIGINT, SIGFPE, SIGQUIT, SIGTSTP, SIGHUP, SIGWINCH. These
860 functions are the actual signal handlers associated to the signals
861 via calls to signal(). The only job for these functions is to
862 enqueue the appropriate event/procedure with the event loop. Such
863 procedures are the old signal handlers. The event loop will take
864 care of invoking the queued procedures to perform the usual tasks
865 associated with the reception of the signal. */
866 /* NOTE: 1999-04-30 This is the asynchronous version of init_signals.
867 init_signals will become obsolete as we move to have to event loop
868 as the default for gdb. */
870 async_init_signals (void)
872 initialize_async_signal_handlers ();
874 quit_serial_event = make_serial_event ();
876 signal (SIGINT, handle_sigint);
878 create_async_signal_handler (async_request_quit, NULL);
879 signal (SIGTERM, handle_sigterm);
881 = create_async_signal_handler (async_sigterm_handler, NULL);
883 /* If SIGTRAP was set to SIG_IGN, then the SIG_IGN will get passed
884 to the inferior and breakpoints will be ignored. */
886 signal (SIGTRAP, SIG_DFL);
890 /* If we initialize SIGQUIT to SIG_IGN, then the SIG_IGN will get
891 passed to the inferior, which we don't want. It would be
892 possible to do a "signal (SIGQUIT, SIG_DFL)" after we fork, but
893 on BSD4.3 systems using vfork, that can affect the
894 GDB process as well as the inferior (the signal handling tables
895 might be in memory, shared between the two). Since we establish
896 a handler for SIGQUIT, when we call exec it will set the signal
897 to SIG_DFL for us. */
898 signal (SIGQUIT, handle_sigquit);
900 create_async_signal_handler (async_do_nothing, NULL);
903 if (signal (SIGHUP, handle_sighup) != SIG_IGN)
905 create_async_signal_handler (async_disconnect, NULL);
908 create_async_signal_handler (async_do_nothing, NULL);
910 signal (SIGFPE, handle_sigfpe);
912 create_async_signal_handler (async_float_handler, NULL);
916 create_async_signal_handler (async_sigtstp_handler, NULL);
923 quit_serial_event_set (void)
925 serial_event_set (quit_serial_event);
931 quit_serial_event_clear (void)
933 serial_event_clear (quit_serial_event);
936 /* Return the selectable file descriptor of the serial event
937 associated with the quit flag. */
940 quit_serial_event_fd (void)
942 return serial_event_fd (quit_serial_event);
948 default_quit_handler (void)
950 if (check_quit_flag ())
952 if (target_terminal::is_ours ())
955 target_pass_ctrlc ();
960 quit_handler_ftype *quit_handler = default_quit_handler;
962 /* Handle a SIGINT. */
965 handle_sigint (int sig)
967 signal (sig, handle_sigint);
969 /* We could be running in a loop reading in symfiles or something so
970 it may be quite a while before we get back to the event loop. So
971 set quit_flag to 1 here. Then if QUIT is called before we get to
972 the event loop, we will unwind as expected. */
975 /* In case nothing calls QUIT before the event loop is reached, the
976 event loop handles it. */
977 mark_async_signal_handler (sigint_token);
980 /* See gdb_select.h. */
983 interruptible_select (int n,
984 fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
985 struct timeval *timeout)
993 readfds = &my_readfds;
994 FD_ZERO (&my_readfds);
997 fd = quit_serial_event_fd ();
998 FD_SET (fd, readfds);
1004 res = gdb_select (n, readfds, writefds, exceptfds, timeout);
1006 while (res == -1 && errno == EINTR);
1008 if (res == 1 && FD_ISSET (fd, readfds))
1016 /* Handle GDB exit upon receiving SIGTERM if target_can_async_p (). */
1019 async_sigterm_handler (gdb_client_data arg)
1021 quit_force (NULL, 0);
1025 volatile int sync_quit_force_run;
1027 /* Quit GDB if SIGTERM is received.
1028 GDB would quit anyway, but this way it will clean up properly. */
1030 handle_sigterm (int sig)
1032 signal (sig, handle_sigterm);
1034 sync_quit_force_run = 1;
1037 mark_async_signal_handler (async_sigterm_token);
1040 /* Do the quit. All the checks have been done by the caller. */
1042 async_request_quit (gdb_client_data arg)
1044 /* If the quit_flag has gotten reset back to 0 by the time we get
1045 back here, that means that an exception was thrown to unwind the
1046 current command before we got back to the event loop. So there
1047 is no reason to call quit again here. */
1052 /* Tell the event loop what to do if SIGQUIT is received.
1053 See event-signal.c. */
1055 handle_sigquit (int sig)
1057 mark_async_signal_handler (sigquit_token);
1058 signal (sig, handle_sigquit);
1062 #if defined (SIGQUIT) || defined (SIGHUP)
1063 /* Called by the event loop in response to a SIGQUIT or an
1066 async_do_nothing (gdb_client_data arg)
1068 /* Empty function body. */
1073 /* Tell the event loop what to do if SIGHUP is received.
1074 See event-signal.c. */
1076 handle_sighup (int sig)
1078 mark_async_signal_handler (sighup_token);
1079 signal (sig, handle_sighup);
1082 /* Called by the event loop to process a SIGHUP. */
1084 async_disconnect (gdb_client_data arg)
1092 CATCH (exception, RETURN_MASK_ALL)
1094 fputs_filtered ("Could not kill the program being debugged",
1096 exception_print (gdb_stderr, exception);
1104 CATCH (exception, RETURN_MASK_ALL)
1109 signal (SIGHUP, SIG_DFL); /*FIXME: ??????????? */
1116 handle_sigtstp (int sig)
1118 mark_async_signal_handler (sigtstp_token);
1119 signal (sig, handle_sigtstp);
1123 async_sigtstp_handler (gdb_client_data arg)
1125 char *prompt = get_prompt ();
1127 signal (SIGTSTP, SIG_DFL);
1128 #if HAVE_SIGPROCMASK
1132 sigemptyset (&zero);
1133 sigprocmask (SIG_SETMASK, &zero, 0);
1135 #elif HAVE_SIGSETMASK
1139 signal (SIGTSTP, handle_sigtstp);
1140 printf_unfiltered ("%s", prompt);
1141 gdb_flush (gdb_stdout);
1143 /* Forget about any previous command -- null line now will do
1147 #endif /* SIGTSTP */
1149 /* Tell the event loop what to do if SIGFPE is received.
1150 See event-signal.c. */
1152 handle_sigfpe (int sig)
1154 mark_async_signal_handler (sigfpe_token);
1155 signal (sig, handle_sigfpe);
1158 /* Event loop will call this functin to process a SIGFPE. */
1160 async_float_handler (gdb_client_data arg)
1162 /* This message is based on ANSI C, section 4.7. Note that integer
1163 divide by zero causes this, so "float" is a misnomer. */
1164 error (_("Erroneous arithmetic operation."));
1168 /* Set things up for readline to be invoked via the alternate
1169 interface, i.e. via a callback function
1170 (gdb_rl_callback_read_char), and hook up instream to the event
1174 gdb_setup_readline (int editing)
1176 struct ui *ui = current_ui;
1178 /* This function is a noop for the sync case. The assumption is
1179 that the sync setup is ALL done in gdb_init, and we would only
1180 mess it up here. The sync stuff should really go away over
1183 gdb_stdout = new stdio_file (ui->outstream);
1184 gdb_stderr = new stderr_file (ui->errstream);
1185 gdb_stdlog = gdb_stderr; /* for moment */
1186 gdb_stdtarg = gdb_stderr; /* for moment */
1187 gdb_stdtargerr = gdb_stderr; /* for moment */
1189 /* If the input stream is connected to a terminal, turn on editing.
1190 However, that is only allowed on the main UI, as we can only have
1191 one instance of readline. */
1192 if (ISATTY (ui->instream) && editing && ui == main_ui)
1194 /* Tell gdb that we will be using the readline library. This
1195 could be overwritten by a command in .gdbinit like 'set
1196 editing on' or 'off'. */
1197 ui->command_editing = 1;
1199 /* When a character is detected on instream by select or poll,
1200 readline will be invoked via this callback function. */
1201 ui->call_readline = gdb_rl_callback_read_char_wrapper;
1203 /* Tell readline to use the same input stream that gdb uses. */
1204 rl_instream = ui->instream;
1208 ui->command_editing = 0;
1209 ui->call_readline = gdb_readline_no_editing_callback;
1212 /* Now create the event source for this UI's input file descriptor.
1213 Another source is going to be the target program (inferior), but
1214 that must be registered only when it actually exists (I.e. after
1215 we say 'run' or after we connect to a remote target. */
1216 ui_register_input_event_handler (ui);
1219 /* Disable command input through the standard CLI channels. Used in
1220 the suspend proc for interpreters that use the standard gdb readline
1221 interface, like the cli & the mi. */
1224 gdb_disable_readline (void)
1226 struct ui *ui = current_ui;
1228 /* FIXME - It is too heavyweight to delete and remake these every
1229 time you run an interpreter that needs readline. It is probably
1230 better to have the interpreters cache these, which in turn means
1231 that this needs to be moved into interpreter specific code. */
1234 ui_file_delete (gdb_stdout);
1235 ui_file_delete (gdb_stderr);
1238 gdb_stdtargerr = NULL;
1241 if (ui->command_editing)
1242 gdb_rl_callback_handler_remove ();
1243 delete_file_handler (ui->input_fd);