1 /* Low level interface to ptrace, for GDB when running under Unix.
2 Copyright 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995,
3 1996, 1998, 1999, 2000, 2001, 2002, 2003, 2004
4 Free Software Foundation, Inc.
5
6 This file is part of GDB.
7
8 This program is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 2 of the License, or
11 (at your option) any later version.
12
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
17
18 You should have received a copy of the GNU General Public License
19 along with this program; if not, write to the Free Software
20 Foundation, Inc., 59 Temple Place - Suite 330,
21 Boston, MA 02111-1307, USA. */
22
23 #include "defs.h"
24 #include "frame.h"
25 #include "inferior.h"
26 #include "command.h"
27 #include "serial.h"
28 #include "terminal.h"
29 #include "target.h"
30 #include "gdbthread.h"
31
32 #include "gdb_string.h"
33 #include <signal.h>
34 #include <fcntl.h>
35 #ifdef HAVE_SYS_SELECT_H
36 #include <sys/select.h>
37 #endif
38
39 #include "inflow.h"
40
41 #ifdef HAVE_SYS_IOCTL_H
42 #include <sys/ioctl.h>
43 #endif
44
45 #ifndef O_NOCTTY
46 #define O_NOCTTY 0
47 #endif
48
49 #if defined (SIGIO) && defined (FASYNC) && defined (FD_SET) && defined (F_SETOWN)
50 static void handle_sigio (int);
51 #endif
52
53 extern void _initialize_inflow (void);
54
55 static void pass_signal (int);
56
57 static void kill_command (char *, int);
58
59 static void terminal_ours_1 (int);
60
61 /* Record terminal status separately for debugger and inferior. */
62
63 static struct serial *stdin_serial;
64
65 /* TTY state for the inferior. We save it whenever the inferior stops, and
66 restore it when it resumes. */
67 static serial_ttystate inferior_ttystate;
68
69 /* Our own tty state, which we restore every time we need to deal with the
70 terminal. We only set it once, when GDB first starts. The settings of
71 flags which readline saves and restores and unimportant. */
72 static serial_ttystate our_ttystate;
73
74 /* fcntl flags for us and the inferior. Saved and restored just like
75 {our,inferior}_ttystate. */
76 static int tflags_inferior;
77 static int tflags_ours;
78
79 #ifdef PROCESS_GROUP_TYPE
80 /* Process group for us and the inferior. Saved and restored just like
81 {our,inferior}_ttystate. */
82 PROCESS_GROUP_TYPE our_process_group;
83 PROCESS_GROUP_TYPE inferior_process_group;
84 #endif
85
86 /* While the inferior is running, we want SIGINT and SIGQUIT to go to the
87 inferior only. If we have job control, that takes care of it. If not,
88 we save our handlers in these two variables and set SIGINT and SIGQUIT
89 to SIG_IGN. */
90
91 static void (*sigint_ours) ();
92 static void (*sigquit_ours) ();
93
94 /* The name of the tty (from the `tty' command) that we gave to the inferior
95 when it was last started. */
96
97 static char *inferior_thisrun_terminal;
98
99 /* Nonzero if our terminal settings are in effect. Zero if the
100 inferior's settings are in effect. Ignored if !gdb_has_a_terminal
101 (). */
102
103 int terminal_is_ours;
104
105 enum
106 {
107 yes, no, have_not_checked
108 }
109 gdb_has_a_terminal_flag = have_not_checked;
110
111 /* Does GDB have a terminal (on stdin)? */
112 int
gdb_has_a_terminal(void)113 gdb_has_a_terminal (void)
114 {
115 switch (gdb_has_a_terminal_flag)
116 {
117 case yes:
118 return 1;
119 case no:
120 return 0;
121 case have_not_checked:
122 /* Get all the current tty settings (including whether we have a
123 tty at all!). Can't do this in _initialize_inflow because
124 serial_fdopen() won't work until the serial_ops_list is
125 initialized. */
126
127 #ifdef F_GETFL
128 tflags_ours = fcntl (0, F_GETFL, 0);
129 #endif
130
131 gdb_has_a_terminal_flag = no;
132 stdin_serial = serial_fdopen (0);
133 if (stdin_serial != NULL)
134 {
135 our_ttystate = serial_get_tty_state (stdin_serial);
136
137 if (our_ttystate != NULL)
138 {
139 gdb_has_a_terminal_flag = yes;
140 #ifdef HAVE_TERMIOS
141 our_process_group = tcgetpgrp (0);
142 #endif
143 #ifdef HAVE_TERMIO
144 our_process_group = getpgrp ();
145 #endif
146 #ifdef HAVE_SGTTY
147 ioctl (0, TIOCGPGRP, &our_process_group);
148 #endif
149 }
150 }
151
152 return gdb_has_a_terminal_flag == yes;
153 default:
154 /* "Can't happen". */
155 return 0;
156 }
157 }
158
159 /* Macro for printing errors from ioctl operations */
160
161 #define OOPSY(what) \
162 if (result == -1) \
163 fprintf_unfiltered(gdb_stderr, "[%s failed in terminal_inferior: %s]\n", \
164 what, safe_strerror (errno))
165
166 static void terminal_ours_1 (int);
167
168 /* Initialize the terminal settings we record for the inferior,
169 before we actually run the inferior. */
170
171 void
terminal_init_inferior_with_pgrp(int pgrp)172 terminal_init_inferior_with_pgrp (int pgrp)
173 {
174 if (gdb_has_a_terminal ())
175 {
176 /* We could just as well copy our_ttystate (if we felt like
177 adding a new function serial_copy_tty_state()). */
178 if (inferior_ttystate)
179 xfree (inferior_ttystate);
180 inferior_ttystate = serial_get_tty_state (stdin_serial);
181
182 #ifdef PROCESS_GROUP_TYPE
183 inferior_process_group = pgrp;
184 #endif
185
186 /* Make sure that next time we call terminal_inferior (which will be
187 before the program runs, as it needs to be), we install the new
188 process group. */
189 terminal_is_ours = 1;
190 }
191 }
192
193 /* Save the terminal settings again. This is necessary for the TUI
194 when it switches to TUI or non-TUI mode; curses changes the terminal
195 and gdb must be able to restore it correctly. */
196
197 void
terminal_save_ours(void)198 terminal_save_ours (void)
199 {
200 if (gdb_has_a_terminal ())
201 {
202 /* We could just as well copy our_ttystate (if we felt like adding
203 a new function serial_copy_tty_state). */
204 if (our_ttystate)
205 xfree (our_ttystate);
206 our_ttystate = serial_get_tty_state (stdin_serial);
207 }
208 }
209
210 void
terminal_init_inferior(void)211 terminal_init_inferior (void)
212 {
213 #ifdef PROCESS_GROUP_TYPE
214 /* This is for Lynx, and should be cleaned up by having Lynx be a separate
215 debugging target with a version of target_terminal_init_inferior which
216 passes in the process group to a generic routine which does all the work
217 (and the non-threaded child_terminal_init_inferior can just pass in
218 inferior_ptid to the same routine). */
219 /* We assume INFERIOR_PID is also the child's process group. */
220 terminal_init_inferior_with_pgrp (PIDGET (inferior_ptid));
221 #endif /* PROCESS_GROUP_TYPE */
222 }
223
224 /* Put the inferior's terminal settings into effect.
225 This is preparation for starting or resuming the inferior. */
226
227 void
terminal_inferior(void)228 terminal_inferior (void)
229 {
230 if (gdb_has_a_terminal () && terminal_is_ours
231 && inferior_ttystate != NULL
232 && inferior_thisrun_terminal == 0)
233 {
234 int result;
235
236 #ifdef F_GETFL
237 /* Is there a reason this is being done twice? It happens both
238 places we use F_SETFL, so I'm inclined to think perhaps there
239 is some reason, however perverse. Perhaps not though... */
240 result = fcntl (0, F_SETFL, tflags_inferior);
241 result = fcntl (0, F_SETFL, tflags_inferior);
242 OOPSY ("fcntl F_SETFL");
243 #endif
244
245 /* Because we were careful to not change in or out of raw mode in
246 terminal_ours, we will not change in our out of raw mode with
247 this call, so we don't flush any input. */
248 result = serial_set_tty_state (stdin_serial, inferior_ttystate);
249 OOPSY ("setting tty state");
250
251 if (!job_control)
252 {
253 sigint_ours = (void (*)()) signal (SIGINT, SIG_IGN);
254 #ifdef SIGQUIT
255 sigquit_ours = (void (*)()) signal (SIGQUIT, SIG_IGN);
256 #endif
257 }
258
259 /* If attach_flag is set, we don't know whether we are sharing a
260 terminal with the inferior or not. (attaching a process
261 without a terminal is one case where we do not; attaching a
262 process which we ran from the same shell as GDB via `&' is
263 one case where we do, I think (but perhaps this is not
264 `sharing' in the sense that we need to save and restore tty
265 state)). I don't know if there is any way to tell whether we
266 are sharing a terminal. So what we do is to go through all
267 the saving and restoring of the tty state, but ignore errors
268 setting the process group, which will happen if we are not
269 sharing a terminal). */
270
271 if (job_control)
272 {
273 #ifdef HAVE_TERMIOS
274 result = tcsetpgrp (0, inferior_process_group);
275 if (!attach_flag)
276 OOPSY ("tcsetpgrp");
277 #endif
278
279 #ifdef HAVE_SGTTY
280 result = ioctl (0, TIOCSPGRP, &inferior_process_group);
281 if (!attach_flag)
282 OOPSY ("TIOCSPGRP");
283 #endif
284 }
285
286 }
287 terminal_is_ours = 0;
288 }
289
290 /* Put some of our terminal settings into effect,
291 enough to get proper results from our output,
292 but do not change into or out of RAW mode
293 so that no input is discarded.
294
295 After doing this, either terminal_ours or terminal_inferior
296 should be called to get back to a normal state of affairs. */
297
298 void
terminal_ours_for_output(void)299 terminal_ours_for_output (void)
300 {
301 terminal_ours_1 (1);
302 }
303
304 /* Put our terminal settings into effect.
305 First record the inferior's terminal settings
306 so they can be restored properly later. */
307
308 void
terminal_ours(void)309 terminal_ours (void)
310 {
311 terminal_ours_1 (0);
312 }
313
314 /* output_only is not used, and should not be used unless we introduce
315 separate terminal_is_ours and terminal_is_ours_for_output
316 flags. */
317
318 static void
terminal_ours_1(int output_only)319 terminal_ours_1 (int output_only)
320 {
321 /* Checking inferior_thisrun_terminal is necessary so that
322 if GDB is running in the background, it won't block trying
323 to do the ioctl()'s below. Checking gdb_has_a_terminal
324 avoids attempting all the ioctl's when running in batch. */
325 if (inferior_thisrun_terminal != 0 || gdb_has_a_terminal () == 0)
326 return;
327
328 if (!terminal_is_ours)
329 {
330 #ifdef SIGTTOU
331 /* Ignore this signal since it will happen when we try to set the
332 pgrp. */
333 void (*osigttou) () = NULL;
334 #endif
335 int result;
336
337 terminal_is_ours = 1;
338
339 #ifdef SIGTTOU
340 if (job_control)
341 osigttou = (void (*)()) signal (SIGTTOU, SIG_IGN);
342 #endif
343
344 if (inferior_ttystate)
345 xfree (inferior_ttystate);
346 inferior_ttystate = serial_get_tty_state (stdin_serial);
347 #ifdef HAVE_TERMIOS
348 inferior_process_group = tcgetpgrp (0);
349 #endif
350 #ifdef HAVE_TERMIO
351 inferior_process_group = getpgrp ();
352 #endif
353 #ifdef HAVE_SGTTY
354 ioctl (0, TIOCGPGRP, &inferior_process_group);
355 #endif
356
357 /* Here we used to set ICANON in our ttystate, but I believe this
358 was an artifact from before when we used readline. Readline sets
359 the tty state when it needs to.
360 FIXME-maybe: However, query() expects non-raw mode and doesn't
361 use readline. Maybe query should use readline (on the other hand,
362 this only matters for HAVE_SGTTY, not termio or termios, I think). */
363
364 /* Set tty state to our_ttystate. We don't change in our out of raw
365 mode, to avoid flushing input. We need to do the same thing
366 regardless of output_only, because we don't have separate
367 terminal_is_ours and terminal_is_ours_for_output flags. It's OK,
368 though, since readline will deal with raw mode when/if it needs to.
369 */
370
371 serial_noflush_set_tty_state (stdin_serial, our_ttystate,
372 inferior_ttystate);
373
374 if (job_control)
375 {
376 #ifdef HAVE_TERMIOS
377 result = tcsetpgrp (0, our_process_group);
378 #if 0
379 /* This fails on Ultrix with EINVAL if you run the testsuite
380 in the background with nohup, and then log out. GDB never
381 used to check for an error here, so perhaps there are other
382 such situations as well. */
383 if (result == -1)
384 fprintf_unfiltered (gdb_stderr, "[tcsetpgrp failed in terminal_ours: %s]\n",
385 safe_strerror (errno));
386 #endif
387 #endif /* termios */
388
389 #ifdef HAVE_SGTTY
390 result = ioctl (0, TIOCSPGRP, &our_process_group);
391 #endif
392 }
393
394 #ifdef SIGTTOU
395 if (job_control)
396 signal (SIGTTOU, osigttou);
397 #endif
398
399 if (!job_control)
400 {
401 signal (SIGINT, sigint_ours);
402 #ifdef SIGQUIT
403 signal (SIGQUIT, sigquit_ours);
404 #endif
405 }
406
407 #ifdef F_GETFL
408 tflags_inferior = fcntl (0, F_GETFL, 0);
409
410 /* Is there a reason this is being done twice? It happens both
411 places we use F_SETFL, so I'm inclined to think perhaps there
412 is some reason, however perverse. Perhaps not though... */
413 result = fcntl (0, F_SETFL, tflags_ours);
414 result = fcntl (0, F_SETFL, tflags_ours);
415 #endif
416
417 result = result; /* lint */
418 }
419 }
420
421 void
term_info(char * arg,int from_tty)422 term_info (char *arg, int from_tty)
423 {
424 target_terminal_info (arg, from_tty);
425 }
426
427 void
child_terminal_info(char * args,int from_tty)428 child_terminal_info (char *args, int from_tty)
429 {
430 if (!gdb_has_a_terminal ())
431 {
432 printf_filtered ("This GDB does not control a terminal.\n");
433 return;
434 }
435
436 printf_filtered ("Inferior's terminal status (currently saved by GDB):\n");
437
438 /* First the fcntl flags. */
439 {
440 int flags;
441
442 flags = tflags_inferior;
443
444 printf_filtered ("File descriptor flags = ");
445
446 #ifndef O_ACCMODE
447 #define O_ACCMODE (O_RDONLY | O_WRONLY | O_RDWR)
448 #endif
449 /* (O_ACCMODE) parens are to avoid Ultrix header file bug */
450 switch (flags & (O_ACCMODE))
451 {
452 case O_RDONLY:
453 printf_filtered ("O_RDONLY");
454 break;
455 case O_WRONLY:
456 printf_filtered ("O_WRONLY");
457 break;
458 case O_RDWR:
459 printf_filtered ("O_RDWR");
460 break;
461 }
462 flags &= ~(O_ACCMODE);
463
464 #ifdef O_NONBLOCK
465 if (flags & O_NONBLOCK)
466 printf_filtered (" | O_NONBLOCK");
467 flags &= ~O_NONBLOCK;
468 #endif
469
470 #if defined (O_NDELAY)
471 /* If O_NDELAY and O_NONBLOCK are defined to the same thing, we will
472 print it as O_NONBLOCK, which is good cause that is what POSIX
473 has, and the flag will already be cleared by the time we get here. */
474 if (flags & O_NDELAY)
475 printf_filtered (" | O_NDELAY");
476 flags &= ~O_NDELAY;
477 #endif
478
479 if (flags & O_APPEND)
480 printf_filtered (" | O_APPEND");
481 flags &= ~O_APPEND;
482
483 #if defined (O_BINARY)
484 if (flags & O_BINARY)
485 printf_filtered (" | O_BINARY");
486 flags &= ~O_BINARY;
487 #endif
488
489 if (flags)
490 printf_filtered (" | 0x%x", flags);
491 printf_filtered ("\n");
492 }
493
494 #ifdef PROCESS_GROUP_TYPE
495 printf_filtered ("Process group = %d\n",
496 (int) inferior_process_group);
497 #endif
498
499 serial_print_tty_state (stdin_serial, inferior_ttystate, gdb_stdout);
500 }
501
502 /* NEW_TTY_PREFORK is called before forking a new child process,
503 so we can record the state of ttys in the child to be formed.
504 TTYNAME is null if we are to share the terminal with gdb;
505 or points to a string containing the name of the desired tty.
506
507 NEW_TTY is called in new child processes under Unix, which will
508 become debugger target processes. This actually switches to
509 the terminal specified in the NEW_TTY_PREFORK call. */
510
511 void
new_tty_prefork(char * ttyname)512 new_tty_prefork (char *ttyname)
513 {
514 /* Save the name for later, for determining whether we and the child
515 are sharing a tty. */
516 inferior_thisrun_terminal = ttyname;
517 }
518
519 void
new_tty(void)520 new_tty (void)
521 {
522 int tty;
523
524 if (inferior_thisrun_terminal == 0)
525 return;
526 #if !defined(__GO32__) && !defined(_WIN32)
527 #ifdef TIOCNOTTY
528 /* Disconnect the child process from our controlling terminal. On some
529 systems (SVR4 for example), this may cause a SIGTTOU, so temporarily
530 ignore SIGTTOU. */
531 tty = open ("/dev/tty", O_RDWR);
532 if (tty > 0)
533 {
534 void (*osigttou) ();
535
536 osigttou = (void (*)()) signal (SIGTTOU, SIG_IGN);
537 ioctl (tty, TIOCNOTTY, 0);
538 close (tty);
539 signal (SIGTTOU, osigttou);
540 }
541 #endif
542
543 /* Now open the specified new terminal. */
544 tty = open (inferior_thisrun_terminal, O_RDWR | O_NOCTTY);
545 if (tty == -1)
546 {
547 print_sys_errmsg (inferior_thisrun_terminal, errno);
548 _exit (1);
549 }
550
551 /* Avoid use of dup2; doesn't exist on all systems. */
552 if (tty != 0)
553 {
554 close (0);
555 dup (tty);
556 }
557 if (tty != 1)
558 {
559 close (1);
560 dup (tty);
561 }
562 if (tty != 2)
563 {
564 close (2);
565 dup (tty);
566 }
567 if (tty > 2)
568 close (tty);
569 #endif /* !go32 && !win32 */
570 }
571
572 /* Kill the inferior process. Make us have no inferior. */
573
574 static void
kill_command(char * arg,int from_tty)575 kill_command (char *arg, int from_tty)
576 {
577 /* FIXME: This should not really be inferior_ptid (or target_has_execution).
578 It should be a distinct flag that indicates that a target is active, cuz
579 some targets don't have processes! */
580
581 if (ptid_equal (inferior_ptid, null_ptid))
582 error ("The program is not being run.");
583 if (!query ("Kill the program being debugged? "))
584 error ("Not confirmed.");
585 target_kill ();
586
587 init_thread_list (); /* Destroy thread info */
588
589 /* Killing off the inferior can leave us with a core file. If so,
590 print the state we are left in. */
591 if (target_has_stack)
592 {
593 printf_filtered ("In %s,\n", target_longname);
594 if (deprecated_selected_frame == NULL)
595 fputs_filtered ("No selected stack frame.\n", gdb_stdout);
596 else
597 print_stack_frame (get_selected_frame (), 1, SRC_AND_LOC);
598 }
599 bfd_cache_close_all ();
600 }
601
602 /* Call set_sigint_trap when you need to pass a signal on to an attached
603 process when handling SIGINT */
604
605 static void
pass_signal(int signo)606 pass_signal (int signo)
607 {
608 #ifndef _WIN32
609 kill (PIDGET (inferior_ptid), SIGINT);
610 #endif
611 }
612
613 static void (*osig) ();
614
615 void
set_sigint_trap(void)616 set_sigint_trap (void)
617 {
618 if (attach_flag || inferior_thisrun_terminal)
619 {
620 osig = (void (*)()) signal (SIGINT, pass_signal);
621 }
622 }
623
624 void
clear_sigint_trap(void)625 clear_sigint_trap (void)
626 {
627 if (attach_flag || inferior_thisrun_terminal)
628 {
629 signal (SIGINT, osig);
630 }
631 }
632
633 #if defined (SIGIO) && defined (FASYNC) && defined (FD_SET) && defined (F_SETOWN)
634 static void (*old_sigio) ();
635
636 static void
handle_sigio(int signo)637 handle_sigio (int signo)
638 {
639 int numfds;
640 fd_set readfds;
641
642 signal (SIGIO, handle_sigio);
643
644 FD_ZERO (&readfds);
645 FD_SET (target_activity_fd, &readfds);
646 numfds = select (target_activity_fd + 1, &readfds, NULL, NULL, NULL);
647 if (numfds >= 0 && FD_ISSET (target_activity_fd, &readfds))
648 {
649 #ifndef _WIN32
650 if ((*target_activity_function) ())
651 kill (PIDGET (inferior_ptid), SIGINT);
652 #endif
653 }
654 }
655
656 static int old_fcntl_flags;
657
658 void
set_sigio_trap(void)659 set_sigio_trap (void)
660 {
661 if (target_activity_function)
662 {
663 old_sigio = (void (*)()) signal (SIGIO, handle_sigio);
664 fcntl (target_activity_fd, F_SETOWN, getpid ());
665 old_fcntl_flags = fcntl (target_activity_fd, F_GETFL, 0);
666 fcntl (target_activity_fd, F_SETFL, old_fcntl_flags | FASYNC);
667 }
668 }
669
670 void
clear_sigio_trap(void)671 clear_sigio_trap (void)
672 {
673 if (target_activity_function)
674 {
675 signal (SIGIO, old_sigio);
676 fcntl (target_activity_fd, F_SETFL, old_fcntl_flags);
677 }
678 }
679 #else /* No SIGIO. */
680 void
set_sigio_trap(void)681 set_sigio_trap (void)
682 {
683 if (target_activity_function)
684 internal_error (__FILE__, __LINE__, "failed internal consistency check");
685 }
686
687 void
clear_sigio_trap(void)688 clear_sigio_trap (void)
689 {
690 if (target_activity_function)
691 internal_error (__FILE__, __LINE__, "failed internal consistency check");
692 }
693 #endif /* No SIGIO. */
694
695
696 /* This is here because this is where we figure out whether we (probably)
697 have job control. Just using job_control only does part of it because
698 setpgid or setpgrp might not exist on a system without job control.
699 It might be considered misplaced (on the other hand, process groups and
700 job control are closely related to ttys).
701
702 For a more clean implementation, in libiberty, put a setpgid which merely
703 calls setpgrp and a setpgrp which does nothing (any system with job control
704 will have one or the other). */
705 int
gdb_setpgid(void)706 gdb_setpgid (void)
707 {
708 int retval = 0;
709
710 if (job_control)
711 {
712 #if defined (HAVE_TERMIOS) || defined (TIOCGPGRP)
713 #ifdef HAVE_SETPGID
714 /* The call setpgid (0, 0) is supposed to work and mean the same
715 thing as this, but on Ultrix 4.2A it fails with EPERM (and
716 setpgid (getpid (), getpid ()) succeeds). */
717 retval = setpgid (getpid (), getpid ());
718 #else
719 #ifdef HAVE_SETPGRP
720 #ifdef SETPGRP_VOID
721 retval = setpgrp ();
722 #else
723 retval = setpgrp (getpid (), getpid ());
724 #endif
725 #endif /* HAVE_SETPGRP */
726 #endif /* HAVE_SETPGID */
727 #endif /* defined (HAVE_TERMIOS) || defined (TIOCGPGRP) */
728 }
729
730 return retval;
731 }
732
733 void
_initialize_inflow(void)734 _initialize_inflow (void)
735 {
736 add_info ("terminal", term_info,
737 "Print inferior's saved terminal status.");
738
739 add_com ("kill", class_run, kill_command,
740 "Kill execution of program being debugged.");
741
742 inferior_ptid = null_ptid;
743
744 terminal_is_ours = 1;
745
746 /* OK, figure out whether we have job control. If neither termios nor
747 sgtty (i.e. termio or go32), leave job_control 0. */
748
749 #if defined (HAVE_TERMIOS)
750 /* Do all systems with termios have the POSIX way of identifying job
751 control? I hope so. */
752 #ifdef _POSIX_JOB_CONTROL
753 job_control = 1;
754 #else
755 #ifdef _SC_JOB_CONTROL
756 job_control = sysconf (_SC_JOB_CONTROL);
757 #else
758 job_control = 0; /* have to assume the worst */
759 #endif /* _SC_JOB_CONTROL */
760 #endif /* _POSIX_JOB_CONTROL */
761 #endif /* HAVE_TERMIOS */
762
763 #ifdef HAVE_SGTTY
764 #ifdef TIOCGPGRP
765 job_control = 1;
766 #else
767 job_control = 0;
768 #endif /* TIOCGPGRP */
769 #endif /* sgtty */
770 }
771