1 /* Top level stuff for GDB, the GNU debugger.
3 Copyright (C) 1999-2019 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() */
40 #include "common/buffer.h"
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;
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;
209 struct ui *ui = current_ui;
213 ui->input_handler (gdb::unique_xmalloc_ptr<char> (rl));
215 catch (const gdb_exception &ex)
220 /* If we caught a GDB exception, longjmp out of the readline
221 callback. There's no other way for the callback to signal to
222 readline that an error happened. A normal return would have
223 readline potentially continue processing further input, redisplay
224 the prompt, etc. (This is what GDB historically did when it was
225 a C program.) Note that since we're long jumping, local variable
226 dtors are NOT run automatically. */
227 if (gdb_rl_expt.reason < 0)
228 throw_exception_sjlj (gdb_rl_expt);
231 /* Change the function to be invoked every time there is a character
232 ready on stdin. This is used when the user sets the editing off,
233 therefore bypassing readline, and letting gdb handle the input
234 itself, via gdb_readline_no_editing_callback. Also it is used in
235 the opposite case in which the user sets editing on again, by
236 restoring readline handling of the input.
238 NOTE: this operates on input_fd, not instream. If we are reading
239 commands from a file, instream will point to the file. However, we
240 always read commands from a file with editing off. This means that
241 the 'set editing on/off' will have effect only on the interactive
245 change_line_handler (int editing)
247 struct ui *ui = current_ui;
249 /* We can only have one instance of readline, so we only allow
250 editing on the main UI. */
254 /* Don't try enabling editing if the interpreter doesn't support it
256 if (!interp_supports_command_editing (top_level_interpreter ())
257 || !interp_supports_command_editing (command_interp ()))
262 gdb_assert (ui == main_ui);
264 /* Turn on editing by using readline. */
265 ui->call_readline = gdb_rl_callback_read_char_wrapper;
269 /* Turn off editing by using gdb_readline_no_editing_callback. */
270 if (ui->command_editing)
271 gdb_rl_callback_handler_remove ();
272 ui->call_readline = gdb_readline_no_editing_callback;
274 ui->command_editing = editing;
277 /* The functions below are wrappers for rl_callback_handler_remove and
278 rl_callback_handler_install that keep track of whether the callback
279 handler is installed in readline. This is necessary because after
280 handling a target event of a background execution command, we may
281 need to reinstall the callback handler if it was removed due to a
282 secondary prompt. See gdb_readline_wrapper_line. We don't
283 unconditionally install the handler for every target event because
284 that also clears the line buffer, thus installing it while the user
285 is typing would lose input. */
287 /* Whether we've registered a callback handler with readline. */
288 static int callback_handler_installed;
290 /* See event-top.h, and above. */
293 gdb_rl_callback_handler_remove (void)
295 gdb_assert (current_ui == main_ui);
297 rl_callback_handler_remove ();
298 callback_handler_installed = 0;
301 /* See event-top.h, and above. Note this wrapper doesn't have an
302 actual callback parameter because we always install
306 gdb_rl_callback_handler_install (const char *prompt)
308 gdb_assert (current_ui == main_ui);
310 /* Calling rl_callback_handler_install resets readline's input
311 buffer. Calling this when we were already processing input
312 therefore loses input. */
313 gdb_assert (!callback_handler_installed);
315 rl_callback_handler_install (prompt, gdb_rl_callback_handler);
316 callback_handler_installed = 1;
319 /* See event-top.h, and above. */
322 gdb_rl_callback_handler_reinstall (void)
324 gdb_assert (current_ui == main_ui);
326 if (!callback_handler_installed)
328 /* Passing NULL as prompt argument tells readline to not display
330 gdb_rl_callback_handler_install (NULL);
334 /* Displays the prompt. If the argument NEW_PROMPT is NULL, the
335 prompt that is displayed is the current top level prompt.
336 Otherwise, it displays whatever NEW_PROMPT is as a local/secondary
339 This is used after each gdb command has completed, and in the
342 1. When the user enters a command line which is ended by '\'
343 indicating that the command will continue on the next line. In
344 that case the prompt that is displayed is the empty string.
346 2. When the user is entering 'commands' for a breakpoint, or
347 actions for a tracepoint. In this case the prompt will be '>'
349 3. On prompting for pagination. */
352 display_gdb_prompt (const char *new_prompt)
354 std::string actual_gdb_prompt;
356 annotate_display_prompt ();
358 /* Reset the nesting depth used when trace-commands is set. */
359 reset_command_nest_depth ();
361 /* Do not call the python hook on an explicit prompt change as
362 passed to this function, as this forms a secondary/local prompt,
363 IE, displayed but not set. */
366 struct ui *ui = current_ui;
368 if (ui->prompt_state == PROMPTED)
369 internal_error (__FILE__, __LINE__, _("double prompt"));
370 else if (ui->prompt_state == PROMPT_BLOCKED)
372 /* This is to trick readline into not trying to display the
373 prompt. Even though we display the prompt using this
374 function, readline still tries to do its own display if
375 we don't call rl_callback_handler_install and
376 rl_callback_handler_remove (which readline detects
377 because a global variable is not set). If readline did
378 that, it could mess up gdb signal handlers for SIGINT.
379 Readline assumes that between calls to rl_set_signals and
380 rl_clear_signals gdb doesn't do anything with the signal
381 handlers. Well, that's not the case, because when the
382 target executes we change the SIGINT signal handler. If
383 we allowed readline to display the prompt, the signal
384 handler change would happen exactly between the calls to
385 the above two functions. Calling
386 rl_callback_handler_remove(), does the job. */
388 if (current_ui->command_editing)
389 gdb_rl_callback_handler_remove ();
392 else if (ui->prompt_state == PROMPT_NEEDED)
394 /* Display the top level prompt. */
395 actual_gdb_prompt = top_level_prompt ();
396 ui->prompt_state = PROMPTED;
400 actual_gdb_prompt = new_prompt;
402 if (current_ui->command_editing)
404 gdb_rl_callback_handler_remove ();
405 gdb_rl_callback_handler_install (actual_gdb_prompt.c_str ());
407 /* new_prompt at this point can be the top of the stack or the one
408 passed in. It can't be NULL. */
411 /* Don't use a _filtered function here. It causes the assumed
412 character position to be off, since the newline we read from
413 the user is not accounted for. */
414 fputs_unfiltered (actual_gdb_prompt.c_str (), gdb_stdout);
415 gdb_flush (gdb_stdout);
419 /* Return the top level prompt, as specified by "set prompt", possibly
420 overriden by the python gdb.prompt_hook hook, and then composed
421 with the prompt prefix and suffix (annotations). */
424 top_level_prompt (void)
428 /* Give observers a chance of changing the prompt. E.g., the python
429 `gdb.prompt_hook' is installed as an observer. */
430 gdb::observers::before_prompt.notify (get_prompt ());
432 prompt = get_prompt ();
434 if (annotation_level >= 2)
436 /* Prefix needs to have new line at end. */
437 const char prefix[] = "\n\032\032pre-prompt\n";
439 /* Suffix needs to have a new line at end and \032 \032 at
441 const char suffix[] = "\n\032\032prompt\n";
443 return std::string (prefix) + prompt + suffix;
452 struct ui *current_ui;
455 /* Get a pointer to the current UI's line buffer. This is used to
456 construct a whole line of input from partial input. */
458 static struct buffer *
459 get_command_line_buffer (void)
461 return ¤t_ui->line_buffer;
464 /* When there is an event ready on the stdin file descriptor, instead
465 of calling readline directly throught the callback function, or
466 instead of calling gdb_readline_no_editing_callback, give gdb a
467 chance to detect errors and do something. */
470 stdin_event_handler (int error, gdb_client_data client_data)
472 struct ui *ui = (struct ui *) client_data;
476 /* Switch to the main UI, so diagnostics always go there. */
477 current_ui = main_ui;
479 delete_file_handler (ui->input_fd);
482 /* If stdin died, we may as well kill gdb. */
483 printf_unfiltered (_("error detected on stdin\n"));
484 quit_command ((char *) 0, 0);
488 /* Simply delete the UI. */
494 /* Switch to the UI whose input descriptor woke up the event
498 /* This makes sure a ^C immediately followed by further input is
499 always processed in that order. E.g,. with input like
500 "^Cprint 1\n", the SIGINT handler runs, marks the async
501 signal handler, and then select/poll may return with stdin
502 ready, instead of -1/EINTR. The
503 gdb.base/double-prompt-target-event-error.exp test exercises
509 call_stdin_event_handler_again_p = 0;
510 ui->call_readline (client_data);
512 while (call_stdin_event_handler_again_p != 0);
519 ui_register_input_event_handler (struct ui *ui)
521 add_file_handler (ui->input_fd, stdin_event_handler, ui);
527 ui_unregister_input_event_handler (struct ui *ui)
529 delete_file_handler (ui->input_fd);
532 /* Re-enable stdin after the end of an execution command in
533 synchronous mode, or after an error from the target, and we aborted
534 the exec operation. */
537 async_enable_stdin (void)
539 struct ui *ui = current_ui;
541 if (ui->prompt_state == PROMPT_BLOCKED)
543 target_terminal::ours ();
544 ui_register_input_event_handler (ui);
545 ui->prompt_state = PROMPT_NEEDED;
549 /* Disable reads from stdin (the console) marking the command as
553 async_disable_stdin (void)
555 struct ui *ui = current_ui;
557 ui->prompt_state = PROMPT_BLOCKED;
558 delete_file_handler (ui->input_fd);
562 /* Handle a gdb command line. This function is called when
563 handle_line_of_input has concatenated one or more input lines into
567 command_handler (const char *command)
569 struct ui *ui = current_ui;
572 if (ui->instream == ui->stdin_stream)
573 reinitialize_more_filter ();
575 scoped_command_stats stat_reporter (true);
577 /* Do not execute commented lines. */
578 for (c = command; *c == ' ' || *c == '\t'; c++)
582 execute_command (command, ui->instream == ui->stdin_stream);
584 /* Do any commands attached to breakpoint we stopped at. */
585 bpstat_do_actions ();
589 /* Append RL, an input line returned by readline or one of its
590 emulations, to CMD_LINE_BUFFER. Returns the command line if we
591 have a whole command line ready to be processed by the command
592 interpreter or NULL if the command line isn't complete yet (input
593 line ends in a backslash). */
596 command_line_append_input_line (struct buffer *cmd_line_buffer, const char *rl)
603 if (len > 0 && rl[len - 1] == '\\')
605 /* Don't copy the backslash and wait for more. */
606 buffer_grow (cmd_line_buffer, rl, len - 1);
611 /* Copy whole line including terminating null, and we're
613 buffer_grow (cmd_line_buffer, rl, len + 1);
614 cmd = cmd_line_buffer->buffer;
620 /* Handle a line of input coming from readline.
622 If the read line ends with a continuation character (backslash),
623 save the partial input in CMD_LINE_BUFFER (except the backslash),
624 and return NULL. Otherwise, save the partial input and return a
625 pointer to CMD_LINE_BUFFER's buffer (null terminated), indicating a
626 whole command line is ready to be executed.
628 Returns EOF on end of file.
630 If REPEAT, handle command repetitions:
632 - If the input command line is NOT empty, the command returned is
633 copied into the global 'saved_command_line' var so that it can
636 - OTOH, if the input command line IS empty, return the previously
637 saved command instead of the empty input line.
641 handle_line_of_input (struct buffer *cmd_line_buffer,
642 const char *rl, int repeat,
643 const char *annotation_suffix)
645 struct ui *ui = current_ui;
646 int from_tty = ui->instream == ui->stdin_stream;
653 cmd = command_line_append_input_line (cmd_line_buffer, rl);
657 /* We have a complete command line now. Prepare for the next
658 command, but leave ownership of memory to the buffer . */
659 cmd_line_buffer->used_size = 0;
661 if (from_tty && annotation_level > 1)
663 printf_unfiltered (("\n\032\032post-"));
664 puts_unfiltered (annotation_suffix);
665 printf_unfiltered (("\n"));
668 #define SERVER_COMMAND_PREFIX "server "
669 server_command = startswith (cmd, SERVER_COMMAND_PREFIX);
672 /* Note that we don't set `saved_command_line'. Between this
673 and the check in dont_repeat, this insures that repeating
674 will still do the right thing. */
675 return cmd + strlen (SERVER_COMMAND_PREFIX);
678 /* Do history expansion if that is wished. */
679 if (history_expansion_p && from_tty && input_interactive_p (current_ui))
684 expanded = history_expand (cmd, &cmd_expansion);
685 gdb::unique_xmalloc_ptr<char> history_value (cmd_expansion);
690 /* Print the changes. */
691 printf_unfiltered ("%s\n", history_value.get ());
693 /* If there was an error, call this function again. */
697 /* history_expand returns an allocated string. Just replace
698 our buffer with it. */
699 len = strlen (history_value.get ());
700 xfree (buffer_finish (cmd_line_buffer));
701 cmd_line_buffer->buffer = history_value.get ();
702 cmd_line_buffer->buffer_size = len + 1;
703 cmd = history_value.release ();
707 /* If we just got an empty line, and that is supposed to repeat the
708 previous command, return the previously saved command. */
709 for (p1 = cmd; *p1 == ' ' || *p1 == '\t'; p1++)
711 if (repeat && *p1 == '\0')
712 return saved_command_line;
714 /* Add command to history if appropriate. Note: lines consisting
715 solely of comments are also added to the command history. This
716 is useful when you type a command, and then realize you don't
717 want to execute it quite yet. You can comment out the command
718 and then later fetch it from the value history and remove the
719 '#'. The kill ring is probably better, but some people are in
720 the habit of commenting things out. */
721 if (*cmd != '\0' && from_tty && input_interactive_p (current_ui))
722 gdb_add_history (cmd);
724 /* Save into global buffer if appropriate. */
727 xfree (saved_command_line);
728 saved_command_line = xstrdup (cmd);
729 return saved_command_line;
735 /* Handle a complete line of input. This is called by the callback
736 mechanism within the readline library. Deal with incomplete
737 commands as well, by saving the partial input in a global
740 NOTE: This is the asynchronous version of the command_line_input
744 command_line_handler (gdb::unique_xmalloc_ptr<char> &&rl)
746 struct buffer *line_buffer = get_command_line_buffer ();
747 struct ui *ui = current_ui;
750 cmd = handle_line_of_input (line_buffer, rl.get (), 1, "prompt");
751 if (cmd == (char *) EOF)
753 /* stdin closed. The connection with the terminal is gone.
754 This happens at the end of a testsuite run, after Expect has
755 hung up but GDB is still alive. In such a case, we just quit
756 gdb killing the inferior program too. */
757 printf_unfiltered ("quit\n");
758 execute_command ("quit", 1);
760 else if (cmd == NULL)
762 /* We don't have a full line yet. Print an empty prompt. */
763 display_gdb_prompt ("");
767 ui->prompt_state = PROMPT_NEEDED;
769 command_handler (cmd);
771 if (ui->prompt_state != PROMPTED)
772 display_gdb_prompt (0);
776 /* Does reading of input from terminal w/o the editing features
777 provided by the readline library. Calls the line input handler
778 once we have a whole input line. */
781 gdb_readline_no_editing_callback (gdb_client_data client_data)
785 struct buffer line_buffer;
786 static int done_once = 0;
787 struct ui *ui = current_ui;
789 buffer_init (&line_buffer);
791 /* Unbuffer the input stream, so that, later on, the calls to fgetc
792 fetch only one char at the time from the stream. The fgetc's will
793 get up to the first newline, but there may be more chars in the
794 stream after '\n'. If we buffer the input and fgetc drains the
795 stream, getting stuff beyond the newline as well, a select, done
796 afterwards will not trigger. */
797 if (!done_once && !ISATTY (ui->instream))
799 setbuf (ui->instream, NULL);
803 /* We still need the while loop here, even though it would seem
804 obvious to invoke gdb_readline_no_editing_callback at every
805 character entered. If not using the readline library, the
806 terminal is in cooked mode, which sends the characters all at
807 once. Poll will notice that the input fd has changed state only
808 after enter is pressed. At this point we still need to fetch all
809 the chars entered. */
813 /* Read from stdin if we are executing a user defined command.
814 This is the right thing for prompt_for_continue, at least. */
815 c = fgetc (ui->instream != NULL ? ui->instream : ui->stdin_stream);
819 if (line_buffer.used_size > 0)
821 /* The last line does not end with a newline. Return it, and
822 if we are called again fgetc will still return EOF and
823 we'll return NULL then. */
826 xfree (buffer_finish (&line_buffer));
827 ui->input_handler (NULL);
833 if (line_buffer.used_size > 0
834 && line_buffer.buffer[line_buffer.used_size - 1] == '\r')
835 line_buffer.used_size--;
839 buffer_grow_char (&line_buffer, c);
842 buffer_grow_char (&line_buffer, '\0');
843 result = buffer_finish (&line_buffer);
844 ui->input_handler (gdb::unique_xmalloc_ptr<char> (result));
848 /* The serial event associated with the QUIT flag. set_quit_flag sets
849 this, and check_quit_flag clears it. Used by interruptible_select
850 to be able to do interruptible I/O with no race with the SIGINT
852 static struct serial_event *quit_serial_event;
854 /* Initialization of signal handlers and tokens. There is a function
855 handle_sig* for each of the signals GDB cares about. Specifically:
856 SIGINT, SIGFPE, SIGQUIT, SIGTSTP, SIGHUP, SIGWINCH. These
857 functions are the actual signal handlers associated to the signals
858 via calls to signal(). The only job for these functions is to
859 enqueue the appropriate event/procedure with the event loop. Such
860 procedures are the old signal handlers. The event loop will take
861 care of invoking the queued procedures to perform the usual tasks
862 associated with the reception of the signal. */
863 /* NOTE: 1999-04-30 This is the asynchronous version of init_signals.
864 init_signals will become obsolete as we move to have to event loop
865 as the default for gdb. */
867 async_init_signals (void)
869 initialize_async_signal_handlers ();
871 quit_serial_event = make_serial_event ();
873 signal (SIGINT, handle_sigint);
875 create_async_signal_handler (async_request_quit, NULL);
876 signal (SIGTERM, handle_sigterm);
878 = create_async_signal_handler (async_sigterm_handler, NULL);
880 /* If SIGTRAP was set to SIG_IGN, then the SIG_IGN will get passed
881 to the inferior and breakpoints will be ignored. */
883 signal (SIGTRAP, SIG_DFL);
887 /* If we initialize SIGQUIT to SIG_IGN, then the SIG_IGN will get
888 passed to the inferior, which we don't want. It would be
889 possible to do a "signal (SIGQUIT, SIG_DFL)" after we fork, but
890 on BSD4.3 systems using vfork, that can affect the
891 GDB process as well as the inferior (the signal handling tables
892 might be in memory, shared between the two). Since we establish
893 a handler for SIGQUIT, when we call exec it will set the signal
894 to SIG_DFL for us. */
895 signal (SIGQUIT, handle_sigquit);
897 create_async_signal_handler (async_do_nothing, NULL);
900 if (signal (SIGHUP, handle_sighup) != SIG_IGN)
902 create_async_signal_handler (async_disconnect, NULL);
905 create_async_signal_handler (async_do_nothing, NULL);
907 signal (SIGFPE, handle_sigfpe);
909 create_async_signal_handler (async_float_handler, NULL);
913 create_async_signal_handler (async_sigtstp_handler, NULL);
920 quit_serial_event_set (void)
922 serial_event_set (quit_serial_event);
928 quit_serial_event_clear (void)
930 serial_event_clear (quit_serial_event);
933 /* Return the selectable file descriptor of the serial event
934 associated with the quit flag. */
937 quit_serial_event_fd (void)
939 return serial_event_fd (quit_serial_event);
945 default_quit_handler (void)
947 if (check_quit_flag ())
949 if (target_terminal::is_ours ())
952 target_pass_ctrlc ();
957 quit_handler_ftype *quit_handler = default_quit_handler;
959 /* Handle a SIGINT. */
962 handle_sigint (int sig)
964 signal (sig, handle_sigint);
966 /* We could be running in a loop reading in symfiles or something so
967 it may be quite a while before we get back to the event loop. So
968 set quit_flag to 1 here. Then if QUIT is called before we get to
969 the event loop, we will unwind as expected. */
972 /* In case nothing calls QUIT before the event loop is reached, the
973 event loop handles it. */
974 mark_async_signal_handler (sigint_token);
977 /* See gdb_select.h. */
980 interruptible_select (int n,
981 fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
982 struct timeval *timeout)
990 readfds = &my_readfds;
991 FD_ZERO (&my_readfds);
994 fd = quit_serial_event_fd ();
995 FD_SET (fd, readfds);
1001 res = gdb_select (n, readfds, writefds, exceptfds, timeout);
1003 while (res == -1 && errno == EINTR);
1005 if (res == 1 && FD_ISSET (fd, readfds))
1013 /* Handle GDB exit upon receiving SIGTERM if target_can_async_p (). */
1016 async_sigterm_handler (gdb_client_data arg)
1018 quit_force (NULL, 0);
1022 volatile int sync_quit_force_run;
1024 /* Quit GDB if SIGTERM is received.
1025 GDB would quit anyway, but this way it will clean up properly. */
1027 handle_sigterm (int sig)
1029 signal (sig, handle_sigterm);
1031 sync_quit_force_run = 1;
1034 mark_async_signal_handler (async_sigterm_token);
1037 /* Do the quit. All the checks have been done by the caller. */
1039 async_request_quit (gdb_client_data arg)
1041 /* If the quit_flag has gotten reset back to 0 by the time we get
1042 back here, that means that an exception was thrown to unwind the
1043 current command before we got back to the event loop. So there
1044 is no reason to call quit again here. */
1049 /* Tell the event loop what to do if SIGQUIT is received.
1050 See event-signal.c. */
1052 handle_sigquit (int sig)
1054 mark_async_signal_handler (sigquit_token);
1055 signal (sig, handle_sigquit);
1059 #if defined (SIGQUIT) || defined (SIGHUP)
1060 /* Called by the event loop in response to a SIGQUIT or an
1063 async_do_nothing (gdb_client_data arg)
1065 /* Empty function body. */
1070 /* Tell the event loop what to do if SIGHUP is received.
1071 See event-signal.c. */
1073 handle_sighup (int sig)
1075 mark_async_signal_handler (sighup_token);
1076 signal (sig, handle_sighup);
1079 /* Called by the event loop to process a SIGHUP. */
1081 async_disconnect (gdb_client_data arg)
1089 catch (const gdb_exception &exception)
1091 fputs_filtered ("Could not kill the program being debugged",
1093 exception_print (gdb_stderr, exception);
1100 catch (const gdb_exception &exception)
1104 signal (SIGHUP, SIG_DFL); /*FIXME: ??????????? */
1111 handle_sigtstp (int sig)
1113 mark_async_signal_handler (sigtstp_token);
1114 signal (sig, handle_sigtstp);
1118 async_sigtstp_handler (gdb_client_data arg)
1120 char *prompt = get_prompt ();
1122 signal (SIGTSTP, SIG_DFL);
1123 #if HAVE_SIGPROCMASK
1127 sigemptyset (&zero);
1128 sigprocmask (SIG_SETMASK, &zero, 0);
1130 #elif HAVE_SIGSETMASK
1134 signal (SIGTSTP, handle_sigtstp);
1135 printf_unfiltered ("%s", prompt);
1136 gdb_flush (gdb_stdout);
1138 /* Forget about any previous command -- null line now will do
1142 #endif /* SIGTSTP */
1144 /* Tell the event loop what to do if SIGFPE is received.
1145 See event-signal.c. */
1147 handle_sigfpe (int sig)
1149 mark_async_signal_handler (sigfpe_token);
1150 signal (sig, handle_sigfpe);
1153 /* Event loop will call this functin to process a SIGFPE. */
1155 async_float_handler (gdb_client_data arg)
1157 /* This message is based on ANSI C, section 4.7. Note that integer
1158 divide by zero causes this, so "float" is a misnomer. */
1159 error (_("Erroneous arithmetic operation."));
1163 /* Set things up for readline to be invoked via the alternate
1164 interface, i.e. via a callback function
1165 (gdb_rl_callback_read_char), and hook up instream to the event
1169 gdb_setup_readline (int editing)
1171 struct ui *ui = current_ui;
1173 /* This function is a noop for the sync case. The assumption is
1174 that the sync setup is ALL done in gdb_init, and we would only
1175 mess it up here. The sync stuff should really go away over
1178 gdb_stdout = new stdio_file (ui->outstream);
1179 gdb_stderr = new stderr_file (ui->errstream);
1180 gdb_stdlog = gdb_stderr; /* for moment */
1181 gdb_stdtarg = gdb_stderr; /* for moment */
1182 gdb_stdtargerr = gdb_stderr; /* for moment */
1184 /* If the input stream is connected to a terminal, turn on editing.
1185 However, that is only allowed on the main UI, as we can only have
1186 one instance of readline. */
1187 if (ISATTY (ui->instream) && editing && ui == main_ui)
1189 /* Tell gdb that we will be using the readline library. This
1190 could be overwritten by a command in .gdbinit like 'set
1191 editing on' or 'off'. */
1192 ui->command_editing = 1;
1194 /* When a character is detected on instream by select or poll,
1195 readline will be invoked via this callback function. */
1196 ui->call_readline = gdb_rl_callback_read_char_wrapper;
1198 /* Tell readline to use the same input stream that gdb uses. */
1199 rl_instream = ui->instream;
1203 ui->command_editing = 0;
1204 ui->call_readline = gdb_readline_no_editing_callback;
1207 /* Now create the event source for this UI's input file descriptor.
1208 Another source is going to be the target program (inferior), but
1209 that must be registered only when it actually exists (I.e. after
1210 we say 'run' or after we connect to a remote target. */
1211 ui_register_input_event_handler (ui);
1214 /* Disable command input through the standard CLI channels. Used in
1215 the suspend proc for interpreters that use the standard gdb readline
1216 interface, like the cli & the mi. */
1219 gdb_disable_readline (void)
1221 struct ui *ui = current_ui;
1223 /* FIXME - It is too heavyweight to delete and remake these every
1224 time you run an interpreter that needs readline. It is probably
1225 better to have the interpreters cache these, which in turn means
1226 that this needs to be moved into interpreter specific code. */
1229 ui_file_delete (gdb_stdout);
1230 ui_file_delete (gdb_stderr);
1233 gdb_stdtargerr = NULL;
1236 if (ui->command_editing)
1237 gdb_rl_callback_handler_remove ();
1238 delete_file_handler (ui->input_fd);