event-top.c revision 1.5
1/* Top level stuff for GDB, the GNU debugger. 2 3 Copyright (C) 1999-2015 Free Software Foundation, Inc. 4 5 Written by Elena Zannoni <ezannoni@cygnus.com> of Cygnus Solutions. 6 7 This file is part of GDB. 8 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. 13 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. 18 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/>. */ 21 22#include "defs.h" 23#include "top.h" 24#include "inferior.h" 25#include "infrun.h" 26#include "target.h" 27#include "terminal.h" /* for job_control */ 28#include "event-loop.h" 29#include "event-top.h" 30#include "interps.h" 31#include <signal.h> 32#include "cli/cli-script.h" /* for reset_command_nest_depth */ 33#include "main.h" 34#include "gdbthread.h" 35#include "observer.h" 36#include "continuations.h" 37#include "gdbcmd.h" /* for dont_repeat() */ 38#include "annotate.h" 39#include "maint.h" 40 41/* readline include files. */ 42#include "readline/readline.h" 43#include "readline/history.h" 44 45/* readline defines this. */ 46#undef savestring 47 48static void rl_callback_read_char_wrapper (gdb_client_data client_data); 49static void command_line_handler (char *rl); 50static void change_line_handler (void); 51static void command_handler (char *command); 52static char *top_level_prompt (void); 53 54/* Signal handlers. */ 55#ifdef SIGQUIT 56static void handle_sigquit (int sig); 57#endif 58#ifdef SIGHUP 59static void handle_sighup (int sig); 60#endif 61static void handle_sigfpe (int sig); 62 63/* Functions to be invoked by the event loop in response to 64 signals. */ 65#if defined (SIGQUIT) || defined (SIGHUP) 66static void async_do_nothing (gdb_client_data); 67#endif 68#ifdef SIGHUP 69static void async_disconnect (gdb_client_data); 70#endif 71static void async_float_handler (gdb_client_data); 72#ifdef STOP_SIGNAL 73static void async_stop_sig (gdb_client_data); 74#endif 75static void async_sigterm_handler (gdb_client_data arg); 76 77/* Readline offers an alternate interface, via callback 78 functions. These are all included in the file callback.c in the 79 readline distribution. This file provides (mainly) a function, which 80 the event loop uses as callback (i.e. event handler) whenever an event 81 is detected on the standard input file descriptor. 82 readline_callback_read_char is called (by the GDB event loop) whenever 83 there is a new character ready on the input stream. This function 84 incrementally builds a buffer internal to readline where it 85 accumulates the line read up to the point of invocation. In the 86 special case in which the character read is newline, the function 87 invokes a GDB supplied callback routine, which does the processing of 88 a full command line. This latter routine is the asynchronous analog 89 of the old command_line_input in gdb. Instead of invoking (and waiting 90 for) readline to read the command line and pass it back to 91 command_loop for processing, the new command_line_handler function has 92 the command line already available as its parameter. INPUT_HANDLER is 93 to be set to the function that readline will invoke when a complete 94 line of input is ready. CALL_READLINE is to be set to the function 95 that readline offers as callback to the event_loop. */ 96 97void (*input_handler) (char *); 98void (*call_readline) (gdb_client_data); 99 100/* Important variables for the event loop. */ 101 102/* This is used to determine if GDB is using the readline library or 103 its own simplified form of readline. It is used by the asynchronous 104 form of the set editing command. 105 ezannoni: as of 1999-04-29 I expect that this 106 variable will not be used after gdb is changed to use the event 107 loop as default engine, and event-top.c is merged into top.c. */ 108int async_command_editing_p; 109 110/* This is the annotation suffix that will be used when the 111 annotation_level is 2. */ 112char *async_annotation_suffix; 113 114/* This is used to display the notification of the completion of an 115 asynchronous execution command. */ 116int exec_done_display_p = 0; 117 118/* This is the file descriptor for the input stream that GDB uses to 119 read commands from. */ 120int input_fd; 121 122/* Used by the stdin event handler to compensate for missed stdin events. 123 Setting this to a non-zero value inside an stdin callback makes the callback 124 run again. */ 125int call_stdin_event_handler_again_p; 126 127/* Signal handling variables. */ 128/* Each of these is a pointer to a function that the event loop will 129 invoke if the corresponding signal has received. The real signal 130 handlers mark these functions as ready to be executed and the event 131 loop, in a later iteration, calls them. See the function 132 invoke_async_signal_handler. */ 133static struct async_signal_handler *sigint_token; 134#ifdef SIGHUP 135static struct async_signal_handler *sighup_token; 136#endif 137#ifdef SIGQUIT 138static struct async_signal_handler *sigquit_token; 139#endif 140static struct async_signal_handler *sigfpe_token; 141#ifdef STOP_SIGNAL 142static struct async_signal_handler *sigtstp_token; 143#endif 144static struct async_signal_handler *async_sigterm_token; 145 146/* Structure to save a partially entered command. This is used when 147 the user types '\' at the end of a command line. This is necessary 148 because each line of input is handled by a different call to 149 command_line_handler, and normally there is no state retained 150 between different calls. */ 151static int more_to_come = 0; 152 153struct readline_input_state 154 { 155 char *linebuffer; 156 char *linebuffer_ptr; 157 } 158readline_input_state; 159 160/* This hook is called by rl_callback_read_char_wrapper after each 161 character is processed. */ 162void (*after_char_processing_hook) (void); 163 164 165/* Wrapper function for calling into the readline library. The event 166 loop expects the callback function to have a paramter, while 167 readline expects none. */ 168static void 169rl_callback_read_char_wrapper (gdb_client_data client_data) 170{ 171 rl_callback_read_char (); 172 if (after_char_processing_hook) 173 (*after_char_processing_hook) (); 174} 175 176/* Initialize all the necessary variables, start the event loop, 177 register readline, and stdin, start the loop. The DATA is the 178 interpreter data cookie, ignored for now. */ 179 180void 181cli_command_loop (void *data) 182{ 183 display_gdb_prompt (0); 184 185 /* Now it's time to start the event loop. */ 186 start_event_loop (); 187} 188 189/* Change the function to be invoked every time there is a character 190 ready on stdin. This is used when the user sets the editing off, 191 therefore bypassing readline, and letting gdb handle the input 192 itself, via gdb_readline2. Also it is used in the opposite case in 193 which the user sets editing on again, by restoring readline 194 handling of the input. */ 195static void 196change_line_handler (void) 197{ 198 /* NOTE: this operates on input_fd, not instream. If we are reading 199 commands from a file, instream will point to the file. However in 200 async mode, we always read commands from a file with editing 201 off. This means that the 'set editing on/off' will have effect 202 only on the interactive session. */ 203 204 if (async_command_editing_p) 205 { 206 /* Turn on editing by using readline. */ 207 call_readline = rl_callback_read_char_wrapper; 208 input_handler = command_line_handler; 209 } 210 else 211 { 212 /* Turn off editing by using gdb_readline2. */ 213 gdb_rl_callback_handler_remove (); 214 call_readline = gdb_readline2; 215 216 /* Set up the command handler as well, in case we are called as 217 first thing from .gdbinit. */ 218 input_handler = command_line_handler; 219 } 220} 221 222/* The functions below are wrappers for rl_callback_handler_remove and 223 rl_callback_handler_install that keep track of whether the callback 224 handler is installed in readline. This is necessary because after 225 handling a target event of a background execution command, we may 226 need to reinstall the callback handler if it was removed due to a 227 secondary prompt. See gdb_readline_wrapper_line. We don't 228 unconditionally install the handler for every target event because 229 that also clears the line buffer, thus installing it while the user 230 is typing would lose input. */ 231 232/* Whether we've registered a callback handler with readline. */ 233static int callback_handler_installed; 234 235/* See event-top.h, and above. */ 236 237void 238gdb_rl_callback_handler_remove (void) 239{ 240 rl_callback_handler_remove (); 241 callback_handler_installed = 0; 242} 243 244/* See event-top.h, and above. Note this wrapper doesn't have an 245 actual callback parameter because we always install 246 INPUT_HANDLER. */ 247 248void 249gdb_rl_callback_handler_install (const char *prompt) 250{ 251 /* Calling rl_callback_handler_install resets readline's input 252 buffer. Calling this when we were already processing input 253 therefore loses input. */ 254 gdb_assert (!callback_handler_installed); 255 256 rl_callback_handler_install (prompt, input_handler); 257 callback_handler_installed = 1; 258} 259 260/* See event-top.h, and above. */ 261 262void 263gdb_rl_callback_handler_reinstall (void) 264{ 265 if (!callback_handler_installed) 266 { 267 /* Passing NULL as prompt argument tells readline to not display 268 a prompt. */ 269 gdb_rl_callback_handler_install (NULL); 270 } 271} 272 273/* Displays the prompt. If the argument NEW_PROMPT is NULL, the 274 prompt that is displayed is the current top level prompt. 275 Otherwise, it displays whatever NEW_PROMPT is as a local/secondary 276 prompt. 277 278 This is used after each gdb command has completed, and in the 279 following cases: 280 281 1. When the user enters a command line which is ended by '\' 282 indicating that the command will continue on the next line. In 283 that case the prompt that is displayed is the empty string. 284 285 2. When the user is entering 'commands' for a breakpoint, or 286 actions for a tracepoint. In this case the prompt will be '>' 287 288 3. On prompting for pagination. */ 289 290void 291display_gdb_prompt (const char *new_prompt) 292{ 293 char *actual_gdb_prompt = NULL; 294 struct cleanup *old_chain; 295 296 annotate_display_prompt (); 297 298 /* Reset the nesting depth used when trace-commands is set. */ 299 reset_command_nest_depth (); 300 301 old_chain = make_cleanup (free_current_contents, &actual_gdb_prompt); 302 303 /* Do not call the python hook on an explicit prompt change as 304 passed to this function, as this forms a secondary/local prompt, 305 IE, displayed but not set. */ 306 if (! new_prompt) 307 { 308 if (sync_execution) 309 { 310 /* This is to trick readline into not trying to display the 311 prompt. Even though we display the prompt using this 312 function, readline still tries to do its own display if 313 we don't call rl_callback_handler_install and 314 rl_callback_handler_remove (which readline detects 315 because a global variable is not set). If readline did 316 that, it could mess up gdb signal handlers for SIGINT. 317 Readline assumes that between calls to rl_set_signals and 318 rl_clear_signals gdb doesn't do anything with the signal 319 handlers. Well, that's not the case, because when the 320 target executes we change the SIGINT signal handler. If 321 we allowed readline to display the prompt, the signal 322 handler change would happen exactly between the calls to 323 the above two functions. Calling 324 rl_callback_handler_remove(), does the job. */ 325 326 gdb_rl_callback_handler_remove (); 327 do_cleanups (old_chain); 328 return; 329 } 330 else 331 { 332 /* Display the top level prompt. */ 333 actual_gdb_prompt = top_level_prompt (); 334 } 335 } 336 else 337 actual_gdb_prompt = xstrdup (new_prompt); 338 339 if (async_command_editing_p) 340 { 341 gdb_rl_callback_handler_remove (); 342 gdb_rl_callback_handler_install (actual_gdb_prompt); 343 } 344 /* new_prompt at this point can be the top of the stack or the one 345 passed in. It can't be NULL. */ 346 else 347 { 348 /* Don't use a _filtered function here. It causes the assumed 349 character position to be off, since the newline we read from 350 the user is not accounted for. */ 351 fputs_unfiltered (actual_gdb_prompt, gdb_stdout); 352 gdb_flush (gdb_stdout); 353 } 354 355 do_cleanups (old_chain); 356} 357 358/* Return the top level prompt, as specified by "set prompt", possibly 359 overriden by the python gdb.prompt_hook hook, and then composed 360 with the prompt prefix and suffix (annotations). The caller is 361 responsible for freeing the returned string. */ 362 363static char * 364top_level_prompt (void) 365{ 366 char *prefix; 367 char *prompt = NULL; 368 char *suffix; 369 char *composed_prompt; 370 size_t prompt_length; 371 372 /* Give observers a chance of changing the prompt. E.g., the python 373 `gdb.prompt_hook' is installed as an observer. */ 374 observer_notify_before_prompt (get_prompt ()); 375 376 prompt = xstrdup (get_prompt ()); 377 378 if (annotation_level >= 2) 379 { 380 /* Prefix needs to have new line at end. */ 381 prefix = (char *) alloca (strlen (async_annotation_suffix) + 10); 382 strcpy (prefix, "\n\032\032pre-"); 383 strcat (prefix, async_annotation_suffix); 384 strcat (prefix, "\n"); 385 386 /* Suffix needs to have a new line at end and \032 \032 at 387 beginning. */ 388 suffix = (char *) alloca (strlen (async_annotation_suffix) + 6); 389 strcpy (suffix, "\n\032\032"); 390 strcat (suffix, async_annotation_suffix); 391 strcat (suffix, "\n"); 392 } 393 else 394 { 395 prefix = ""; 396 suffix = ""; 397 } 398 399 prompt_length = strlen (prefix) + strlen (prompt) + strlen (suffix); 400 composed_prompt = xmalloc (prompt_length + 1); 401 402 strcpy (composed_prompt, prefix); 403 strcat (composed_prompt, prompt); 404 strcat (composed_prompt, suffix); 405 406 xfree (prompt); 407 408 return composed_prompt; 409} 410 411/* When there is an event ready on the stdin file desriptor, instead 412 of calling readline directly throught the callback function, or 413 instead of calling gdb_readline2, give gdb a chance to detect 414 errors and do something. */ 415void 416stdin_event_handler (int error, gdb_client_data client_data) 417{ 418 if (error) 419 { 420 printf_unfiltered (_("error detected on stdin\n")); 421 delete_file_handler (input_fd); 422 discard_all_continuations (); 423 discard_all_intermediate_continuations (); 424 /* If stdin died, we may as well kill gdb. */ 425 quit_command ((char *) 0, stdin == instream); 426 } 427 else 428 { 429 do 430 { 431 call_stdin_event_handler_again_p = 0; 432 (*call_readline) (client_data); 433 } while (call_stdin_event_handler_again_p != 0); 434 } 435} 436 437/* Re-enable stdin after the end of an execution command in 438 synchronous mode, or after an error from the target, and we aborted 439 the exec operation. */ 440 441void 442async_enable_stdin (void) 443{ 444 if (sync_execution) 445 { 446 /* See NOTE in async_disable_stdin(). */ 447 /* FIXME: cagney/1999-09-27: Call this before clearing 448 sync_execution. Current target_terminal_ours() implementations 449 check for sync_execution before switching the terminal. */ 450 target_terminal_ours (); 451 sync_execution = 0; 452 } 453} 454 455/* Disable reads from stdin (the console) marking the command as 456 synchronous. */ 457 458void 459async_disable_stdin (void) 460{ 461 sync_execution = 1; 462} 463 464 465/* Handles a gdb command. This function is called by 466 command_line_handler, which has processed one or more input lines 467 into COMMAND. */ 468/* NOTE: 1999-04-30 This is the asynchronous version of the command_loop 469 function. The command_loop function will be obsolete when we 470 switch to use the event loop at every execution of gdb. */ 471static void 472command_handler (char *command) 473{ 474 int stdin_is_tty = ISATTY (stdin); 475 struct cleanup *stat_chain; 476 477 clear_quit_flag (); 478 if (instream == stdin && stdin_is_tty) 479 reinitialize_more_filter (); 480 481 /* If readline returned a NULL command, it means that the connection 482 with the terminal is gone. This happens at the end of a 483 testsuite run, after Expect has hung up but GDB is still alive. 484 In such a case, we just quit gdb killing the inferior program 485 too. */ 486 if (command == 0) 487 { 488 printf_unfiltered ("quit\n"); 489 execute_command ("quit", stdin == instream); 490 } 491 492 stat_chain = make_command_stats_cleanup (1); 493 494 execute_command (command, instream == stdin); 495 496 /* Do any commands attached to breakpoint we stopped at. */ 497 bpstat_do_actions (); 498 499 do_cleanups (stat_chain); 500} 501 502/* Handle a complete line of input. This is called by the callback 503 mechanism within the readline library. Deal with incomplete 504 commands as well, by saving the partial input in a global 505 buffer. */ 506 507/* NOTE: 1999-04-30 This is the asynchronous version of the 508 command_line_input function; command_line_input will become 509 obsolete once we use the event loop as the default mechanism in 510 GDB. */ 511static void 512command_line_handler (char *rl) 513{ 514 static char *linebuffer = 0; 515 static unsigned linelength = 0; 516 char *p; 517 char *p1; 518 char *nline; 519 int repeat = (instream == stdin); 520 521 if (annotation_level > 1 && instream == stdin) 522 { 523 printf_unfiltered (("\n\032\032post-")); 524 puts_unfiltered (async_annotation_suffix); 525 printf_unfiltered (("\n")); 526 } 527 528 if (linebuffer == 0) 529 { 530 linelength = 80; 531 linebuffer = (char *) xmalloc (linelength); 532 linebuffer[0] = '\0'; 533 } 534 535 p = linebuffer; 536 537 if (more_to_come) 538 { 539 strcpy (linebuffer, readline_input_state.linebuffer); 540 p = readline_input_state.linebuffer_ptr; 541 xfree (readline_input_state.linebuffer); 542 more_to_come = 0; 543 } 544 545#ifdef STOP_SIGNAL 546 if (job_control) 547 signal (STOP_SIGNAL, handle_stop_sig); 548#endif 549 550 /* Make sure that all output has been output. Some machines may let 551 you get away with leaving out some of the gdb_flush, but not 552 all. */ 553 wrap_here (""); 554 gdb_flush (gdb_stdout); 555 gdb_flush (gdb_stderr); 556 557 if (source_file_name != NULL) 558 ++source_line_number; 559 560 /* If we are in this case, then command_handler will call quit 561 and exit from gdb. */ 562 if (!rl || rl == (char *) EOF) 563 { 564 command_handler (0); 565 return; /* Lint. */ 566 } 567 if (strlen (rl) + 1 + (p - linebuffer) > linelength) 568 { 569 linelength = strlen (rl) + 1 + (p - linebuffer); 570 nline = (char *) xrealloc (linebuffer, linelength); 571 p += nline - linebuffer; 572 linebuffer = nline; 573 } 574 p1 = rl; 575 /* Copy line. Don't copy null at end. (Leaves line alone 576 if this was just a newline). */ 577 while (*p1) 578 *p++ = *p1++; 579 580 xfree (rl); /* Allocated in readline. */ 581 582 if (p > linebuffer && *(p - 1) == '\\') 583 { 584 *p = '\0'; 585 p--; /* Put on top of '\'. */ 586 587 readline_input_state.linebuffer = xstrdup (linebuffer); 588 readline_input_state.linebuffer_ptr = p; 589 590 /* We will not invoke a execute_command if there is more 591 input expected to complete the command. So, we need to 592 print an empty prompt here. */ 593 more_to_come = 1; 594 display_gdb_prompt (""); 595 return; 596 } 597 598#ifdef STOP_SIGNAL 599 if (job_control) 600 signal (STOP_SIGNAL, SIG_DFL); 601#endif 602 603#define SERVER_COMMAND_LENGTH 7 604 server_command = 605 (p - linebuffer > SERVER_COMMAND_LENGTH) 606 && strncmp (linebuffer, "server ", SERVER_COMMAND_LENGTH) == 0; 607 if (server_command) 608 { 609 /* Note that we don't set `line'. Between this and the check in 610 dont_repeat, this insures that repeating will still do the 611 right thing. */ 612 *p = '\0'; 613 command_handler (linebuffer + SERVER_COMMAND_LENGTH); 614 display_gdb_prompt (0); 615 return; 616 } 617 618 /* Do history expansion if that is wished. */ 619 if (history_expansion_p && instream == stdin 620 && ISATTY (instream)) 621 { 622 char *history_value; 623 int expanded; 624 625 *p = '\0'; /* Insert null now. */ 626 expanded = history_expand (linebuffer, &history_value); 627 if (expanded) 628 { 629 /* Print the changes. */ 630 printf_unfiltered ("%s\n", history_value); 631 632 /* If there was an error, call this function again. */ 633 if (expanded < 0) 634 { 635 xfree (history_value); 636 return; 637 } 638 if (strlen (history_value) > linelength) 639 { 640 linelength = strlen (history_value) + 1; 641 linebuffer = (char *) xrealloc (linebuffer, linelength); 642 } 643 strcpy (linebuffer, history_value); 644 p = linebuffer + strlen (linebuffer); 645 } 646 xfree (history_value); 647 } 648 649 /* If we just got an empty line, and that is supposed to repeat the 650 previous command, return the value in the global buffer. */ 651 if (repeat && p == linebuffer && *p != '\\') 652 { 653 command_handler (saved_command_line); 654 display_gdb_prompt (0); 655 return; 656 } 657 658 for (p1 = linebuffer; *p1 == ' ' || *p1 == '\t'; p1++); 659 if (repeat && !*p1) 660 { 661 command_handler (saved_command_line); 662 display_gdb_prompt (0); 663 return; 664 } 665 666 *p = 0; 667 668 /* Add line to history if appropriate. */ 669 if (*linebuffer && input_from_terminal_p ()) 670 gdb_add_history (linebuffer); 671 672 /* Note: lines consisting solely of comments are added to the command 673 history. This is useful when you type a command, and then 674 realize you don't want to execute it quite yet. You can comment 675 out the command and then later fetch it from the value history 676 and remove the '#'. The kill ring is probably better, but some 677 people are in the habit of commenting things out. */ 678 if (*p1 == '#') 679 *p1 = '\0'; /* Found a comment. */ 680 681 /* Save into global buffer if appropriate. */ 682 if (repeat) 683 { 684 if (linelength > saved_command_line_size) 685 { 686 saved_command_line = xrealloc (saved_command_line, linelength); 687 saved_command_line_size = linelength; 688 } 689 strcpy (saved_command_line, linebuffer); 690 if (!more_to_come) 691 { 692 command_handler (saved_command_line); 693 display_gdb_prompt (0); 694 } 695 return; 696 } 697 698 command_handler (linebuffer); 699 display_gdb_prompt (0); 700 return; 701} 702 703/* Does reading of input from terminal w/o the editing features 704 provided by the readline library. */ 705 706/* NOTE: 1999-04-30 Asynchronous version of gdb_readline; gdb_readline 707 will become obsolete when the event loop is made the default 708 execution for gdb. */ 709void 710gdb_readline2 (gdb_client_data client_data) 711{ 712 int c; 713 char *result; 714 int input_index = 0; 715 int result_size = 80; 716 static int done_once = 0; 717 718 /* Unbuffer the input stream, so that, later on, the calls to fgetc 719 fetch only one char at the time from the stream. The fgetc's will 720 get up to the first newline, but there may be more chars in the 721 stream after '\n'. If we buffer the input and fgetc drains the 722 stream, getting stuff beyond the newline as well, a select, done 723 afterwards will not trigger. */ 724 if (!done_once && !ISATTY (instream)) 725 { 726 setbuf (instream, NULL); 727 done_once = 1; 728 } 729 730 result = (char *) xmalloc (result_size); 731 732 /* We still need the while loop here, even though it would seem 733 obvious to invoke gdb_readline2 at every character entered. If 734 not using the readline library, the terminal is in cooked mode, 735 which sends the characters all at once. Poll will notice that the 736 input fd has changed state only after enter is pressed. At this 737 point we still need to fetch all the chars entered. */ 738 739 while (1) 740 { 741 /* Read from stdin if we are executing a user defined command. 742 This is the right thing for prompt_for_continue, at least. */ 743 c = fgetc (instream ? instream : stdin); 744 745 if (c == EOF) 746 { 747 if (input_index > 0) 748 /* The last line does not end with a newline. Return it, 749 and if we are called again fgetc will still return EOF 750 and we'll return NULL then. */ 751 break; 752 xfree (result); 753 (*input_handler) (0); 754 return; 755 } 756 757 if (c == '\n') 758 { 759 if (input_index > 0 && result[input_index - 1] == '\r') 760 input_index--; 761 break; 762 } 763 764 result[input_index++] = c; 765 while (input_index >= result_size) 766 { 767 result_size *= 2; 768 result = (char *) xrealloc (result, result_size); 769 } 770 } 771 772 result[input_index++] = '\0'; 773 (*input_handler) (result); 774} 775 776 777/* Initialization of signal handlers and tokens. There is a function 778 handle_sig* for each of the signals GDB cares about. Specifically: 779 SIGINT, SIGFPE, SIGQUIT, SIGTSTP, SIGHUP, SIGWINCH. These 780 functions are the actual signal handlers associated to the signals 781 via calls to signal(). The only job for these functions is to 782 enqueue the appropriate event/procedure with the event loop. Such 783 procedures are the old signal handlers. The event loop will take 784 care of invoking the queued procedures to perform the usual tasks 785 associated with the reception of the signal. */ 786/* NOTE: 1999-04-30 This is the asynchronous version of init_signals. 787 init_signals will become obsolete as we move to have to event loop 788 as the default for gdb. */ 789void 790async_init_signals (void) 791{ 792 signal (SIGINT, handle_sigint); 793 sigint_token = 794 create_async_signal_handler (async_request_quit, NULL); 795 signal (SIGTERM, handle_sigterm); 796 async_sigterm_token 797 = create_async_signal_handler (async_sigterm_handler, NULL); 798 799 /* If SIGTRAP was set to SIG_IGN, then the SIG_IGN will get passed 800 to the inferior and breakpoints will be ignored. */ 801#ifdef SIGTRAP 802 signal (SIGTRAP, SIG_DFL); 803#endif 804 805#ifdef SIGQUIT 806 /* If we initialize SIGQUIT to SIG_IGN, then the SIG_IGN will get 807 passed to the inferior, which we don't want. It would be 808 possible to do a "signal (SIGQUIT, SIG_DFL)" after we fork, but 809 on BSD4.3 systems using vfork, that can affect the 810 GDB process as well as the inferior (the signal handling tables 811 might be in memory, shared between the two). Since we establish 812 a handler for SIGQUIT, when we call exec it will set the signal 813 to SIG_DFL for us. */ 814 signal (SIGQUIT, handle_sigquit); 815 sigquit_token = 816 create_async_signal_handler (async_do_nothing, NULL); 817#endif 818#ifdef SIGHUP 819 if (signal (SIGHUP, handle_sighup) != SIG_IGN) 820 sighup_token = 821 create_async_signal_handler (async_disconnect, NULL); 822 else 823 sighup_token = 824 create_async_signal_handler (async_do_nothing, NULL); 825#endif 826 signal (SIGFPE, handle_sigfpe); 827 sigfpe_token = 828 create_async_signal_handler (async_float_handler, NULL); 829 830#ifdef STOP_SIGNAL 831 sigtstp_token = 832 create_async_signal_handler (async_stop_sig, NULL); 833#endif 834} 835 836/* Tell the event loop what to do if SIGINT is received. 837 See event-signal.c. */ 838void 839handle_sigint (int sig) 840{ 841 signal (sig, handle_sigint); 842 843 /* We could be running in a loop reading in symfiles or something so 844 it may be quite a while before we get back to the event loop. So 845 set quit_flag to 1 here. Then if QUIT is called before we get to 846 the event loop, we will unwind as expected. */ 847 848 set_quit_flag (); 849 850 /* If immediate_quit is set, we go ahead and process the SIGINT right 851 away, even if we usually would defer this to the event loop. The 852 assumption here is that it is safe to process ^C immediately if 853 immediate_quit is set. If we didn't, SIGINT would be really 854 processed only the next time through the event loop. To get to 855 that point, though, the command that we want to interrupt needs to 856 finish first, which is unacceptable. If immediate quit is not set, 857 we process SIGINT the next time through the loop, which is fine. */ 858 gdb_call_async_signal_handler (sigint_token, immediate_quit); 859} 860 861/* Handle GDB exit upon receiving SIGTERM if target_can_async_p (). */ 862 863static void 864async_sigterm_handler (gdb_client_data arg) 865{ 866 quit_force (NULL, stdin == instream); 867} 868 869/* See defs.h. */ 870volatile int sync_quit_force_run; 871 872/* Quit GDB if SIGTERM is received. 873 GDB would quit anyway, but this way it will clean up properly. */ 874void 875handle_sigterm (int sig) 876{ 877 signal (sig, handle_sigterm); 878 879 /* Call quit_force in a signal safe way. 880 quit_force itself is not signal safe. */ 881 if (target_can_async_p ()) 882 mark_async_signal_handler (async_sigterm_token); 883 else 884 { 885 sync_quit_force_run = 1; 886 set_quit_flag (); 887 } 888} 889 890/* Do the quit. All the checks have been done by the caller. */ 891void 892async_request_quit (gdb_client_data arg) 893{ 894 /* If the quit_flag has gotten reset back to 0 by the time we get 895 back here, that means that an exception was thrown to unwind the 896 current command before we got back to the event loop. So there 897 is no reason to call quit again here. */ 898 899 if (check_quit_flag ()) 900 quit (); 901} 902 903#ifdef SIGQUIT 904/* Tell the event loop what to do if SIGQUIT is received. 905 See event-signal.c. */ 906static void 907handle_sigquit (int sig) 908{ 909 mark_async_signal_handler (sigquit_token); 910 signal (sig, handle_sigquit); 911} 912#endif 913 914#if defined (SIGQUIT) || defined (SIGHUP) 915/* Called by the event loop in response to a SIGQUIT or an 916 ignored SIGHUP. */ 917static void 918async_do_nothing (gdb_client_data arg) 919{ 920 /* Empty function body. */ 921} 922#endif 923 924#ifdef SIGHUP 925/* Tell the event loop what to do if SIGHUP is received. 926 See event-signal.c. */ 927static void 928handle_sighup (int sig) 929{ 930 mark_async_signal_handler (sighup_token); 931 signal (sig, handle_sighup); 932} 933 934/* Called by the event loop to process a SIGHUP. */ 935static void 936async_disconnect (gdb_client_data arg) 937{ 938 939 TRY 940 { 941 quit_cover (); 942 } 943 944 CATCH (exception, RETURN_MASK_ALL) 945 { 946 fputs_filtered ("Could not kill the program being debugged", 947 gdb_stderr); 948 exception_print (gdb_stderr, exception); 949 } 950 END_CATCH 951 952 TRY 953 { 954 pop_all_targets (); 955 } 956 CATCH (exception, RETURN_MASK_ALL) 957 { 958 } 959 END_CATCH 960 961 signal (SIGHUP, SIG_DFL); /*FIXME: ??????????? */ 962 raise (SIGHUP); 963} 964#endif 965 966#ifdef STOP_SIGNAL 967void 968handle_stop_sig (int sig) 969{ 970 mark_async_signal_handler (sigtstp_token); 971 signal (sig, handle_stop_sig); 972} 973 974static void 975async_stop_sig (gdb_client_data arg) 976{ 977 char *prompt = get_prompt (); 978 979#if STOP_SIGNAL == SIGTSTP 980 signal (SIGTSTP, SIG_DFL); 981#if HAVE_SIGPROCMASK 982 { 983 sigset_t zero; 984 985 sigemptyset (&zero); 986 sigprocmask (SIG_SETMASK, &zero, 0); 987 } 988#elif HAVE_SIGSETMASK 989 sigsetmask (0); 990#endif 991 raise (SIGTSTP); 992 signal (SIGTSTP, handle_stop_sig); 993#else 994 signal (STOP_SIGNAL, handle_stop_sig); 995#endif 996 printf_unfiltered ("%s", prompt); 997 gdb_flush (gdb_stdout); 998 999 /* Forget about any previous command -- null line now will do 1000 nothing. */ 1001 dont_repeat (); 1002} 1003#endif /* STOP_SIGNAL */ 1004 1005/* Tell the event loop what to do if SIGFPE is received. 1006 See event-signal.c. */ 1007static void 1008handle_sigfpe (int sig) 1009{ 1010 mark_async_signal_handler (sigfpe_token); 1011 signal (sig, handle_sigfpe); 1012} 1013 1014/* Event loop will call this functin to process a SIGFPE. */ 1015static void 1016async_float_handler (gdb_client_data arg) 1017{ 1018 /* This message is based on ANSI C, section 4.7. Note that integer 1019 divide by zero causes this, so "float" is a misnomer. */ 1020 error (_("Erroneous arithmetic operation.")); 1021} 1022 1023 1024/* Called by do_setshow_command. */ 1025void 1026set_async_editing_command (char *args, int from_tty, 1027 struct cmd_list_element *c) 1028{ 1029 change_line_handler (); 1030} 1031 1032/* Set things up for readline to be invoked via the alternate 1033 interface, i.e. via a callback function (rl_callback_read_char), 1034 and hook up instream to the event loop. */ 1035void 1036gdb_setup_readline (void) 1037{ 1038 /* This function is a noop for the sync case. The assumption is 1039 that the sync setup is ALL done in gdb_init, and we would only 1040 mess it up here. The sync stuff should really go away over 1041 time. */ 1042 if (!batch_silent) 1043 gdb_stdout = stdio_fileopen (stdout); 1044 gdb_stderr = stderr_fileopen (); 1045 gdb_stdlog = gdb_stderr; /* for moment */ 1046 gdb_stdtarg = gdb_stderr; /* for moment */ 1047 gdb_stdtargerr = gdb_stderr; /* for moment */ 1048 1049 /* If the input stream is connected to a terminal, turn on 1050 editing. */ 1051 if (ISATTY (instream)) 1052 { 1053 /* Tell gdb that we will be using the readline library. This 1054 could be overwritten by a command in .gdbinit like 'set 1055 editing on' or 'off'. */ 1056 async_command_editing_p = 1; 1057 1058 /* When a character is detected on instream by select or poll, 1059 readline will be invoked via this callback function. */ 1060 call_readline = rl_callback_read_char_wrapper; 1061 } 1062 else 1063 { 1064 async_command_editing_p = 0; 1065 call_readline = gdb_readline2; 1066 } 1067 1068 /* When readline has read an end-of-line character, it passes the 1069 complete line to gdb for processing; command_line_handler is the 1070 function that does this. */ 1071 input_handler = command_line_handler; 1072 1073 /* Tell readline to use the same input stream that gdb uses. */ 1074 rl_instream = instream; 1075 1076 /* Get a file descriptor for the input stream, so that we can 1077 register it with the event loop. */ 1078 input_fd = fileno (instream); 1079 1080 /* Now we need to create the event sources for the input file 1081 descriptor. */ 1082 /* At this point in time, this is the only event source that we 1083 register with the even loop. Another source is going to be the 1084 target program (inferior), but that must be registered only when 1085 it actually exists (I.e. after we say 'run' or after we connect 1086 to a remote target. */ 1087 add_file_handler (input_fd, stdin_event_handler, 0); 1088} 1089 1090/* Disable command input through the standard CLI channels. Used in 1091 the suspend proc for interpreters that use the standard gdb readline 1092 interface, like the cli & the mi. */ 1093void 1094gdb_disable_readline (void) 1095{ 1096 /* FIXME - It is too heavyweight to delete and remake these every 1097 time you run an interpreter that needs readline. It is probably 1098 better to have the interpreters cache these, which in turn means 1099 that this needs to be moved into interpreter specific code. */ 1100 1101#if 0 1102 ui_file_delete (gdb_stdout); 1103 ui_file_delete (gdb_stderr); 1104 gdb_stdlog = NULL; 1105 gdb_stdtarg = NULL; 1106 gdb_stdtargerr = NULL; 1107#endif 1108 1109 gdb_rl_callback_handler_remove (); 1110 delete_file_handler (input_fd); 1111} 1112