1 /* Low level interface to ptrace, for GDB when running under Unix.
2 Copyright (C) 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995,
3 1996, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008,
4 2009, 2010, 2011 Free Software Foundation, Inc.
6 This file is part of GDB.
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 3 of the License, or
11 (at your option) any later version.
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.
18 You should have received a copy of the GNU General Public License
19 along with this program. If not, see <http://www.gnu.org/licenses/>. */
28 #include "gdbthread.h"
31 #include "gdb_string.h"
34 #include "gdb_select.h"
38 #ifdef HAVE_SYS_IOCTL_H
39 #include <sys/ioctl.h>
46 extern void _initialize_inflow (void);
48 static void pass_signal (int);
50 static void terminal_ours_1 (int);
52 /* Record terminal status separately for debugger and inferior. */
54 static struct serial
*stdin_serial
;
56 /* Terminal related info we need to keep track of. Each inferior
57 holds an instance of this structure --- we save it whenever the
58 corresponding inferior stops, and restore it to the foreground
59 inferior when it resumes. */
62 /* The name of the tty (from the `tty' command) that we gave to the
63 inferior when it was started. */
66 /* TTY state. We save it whenever the inferior stops, and restore
67 it when it resumes. */
68 serial_ttystate ttystate
;
70 #ifdef PROCESS_GROUP_TYPE
71 /* Process group. Saved and restored just like ttystate. */
72 PROCESS_GROUP_TYPE process_group
;
75 /* fcntl flags. Saved and restored just like ttystate. */
79 /* Our own tty state, which we restore every time we need to deal with
80 the terminal. This is only set once, when GDB first starts. The
81 settings of flags which readline saves and restores and
83 static struct terminal_info our_terminal_info
;
85 static struct terminal_info
*get_inflow_inferior_data (struct inferior
*);
87 #ifdef PROCESS_GROUP_TYPE
89 /* Return the process group of the current inferior. */
92 inferior_process_group (void)
94 return get_inflow_inferior_data (current_inferior ())->process_group
;
98 /* While the inferior is running, we want SIGINT and SIGQUIT to go to the
99 inferior only. If we have job control, that takes care of it. If not,
100 we save our handlers in these two variables and set SIGINT and SIGQUIT
103 static void (*sigint_ours
) ();
104 static void (*sigquit_ours
) ();
106 /* The name of the tty (from the `tty' command) that we're giving to
107 the inferior when starting it up. This is only (and should only
108 be) used as a transient global by new_tty_prefork,
109 create_tty_session, new_tty and new_tty_postfork, all called from
110 fork_inferior, while forking a new child. */
111 static const char *inferior_thisrun_terminal
;
113 /* Nonzero if our terminal settings are in effect. Zero if the
114 inferior's settings are in effect. Ignored if !gdb_has_a_terminal
117 int terminal_is_ours
;
119 #ifdef PROCESS_GROUP_TYPE
120 static PROCESS_GROUP_TYPE
123 int process_group
= -1;
126 process_group
= tcgetpgrp (0);
129 process_group
= getpgrp ();
132 ioctl (0, TIOCGPGRP
, &process_group
);
134 return process_group
;
140 yes
, no
, have_not_checked
142 gdb_has_a_terminal_flag
= have_not_checked
;
144 /* Does GDB have a terminal (on stdin)? */
146 gdb_has_a_terminal (void)
148 switch (gdb_has_a_terminal_flag
)
154 case have_not_checked
:
155 /* Get all the current tty settings (including whether we have a
156 tty at all!). Can't do this in _initialize_inflow because
157 serial_fdopen() won't work until the serial_ops_list is
161 our_terminal_info
.tflags
= fcntl (0, F_GETFL
, 0);
164 gdb_has_a_terminal_flag
= no
;
165 if (stdin_serial
!= NULL
)
167 our_terminal_info
.ttystate
= serial_get_tty_state (stdin_serial
);
169 if (our_terminal_info
.ttystate
!= NULL
)
171 gdb_has_a_terminal_flag
= yes
;
172 #ifdef PROCESS_GROUP_TYPE
173 our_terminal_info
.process_group
= gdb_getpgrp ();
178 return gdb_has_a_terminal_flag
== yes
;
180 /* "Can't happen". */
185 /* Macro for printing errors from ioctl operations */
187 #define OOPSY(what) \
189 fprintf_unfiltered(gdb_stderr, "[%s failed in terminal_inferior: %s]\n", \
190 what, safe_strerror (errno))
192 static void terminal_ours_1 (int);
194 /* Initialize the terminal settings we record for the inferior,
195 before we actually run the inferior. */
198 terminal_init_inferior_with_pgrp (int pgrp
)
200 if (gdb_has_a_terminal ())
202 struct inferior
*inf
= current_inferior ();
203 struct terminal_info
*tinfo
= get_inflow_inferior_data (inf
);
205 /* We could just as well copy our_ttystate (if we felt like
206 adding a new function serial_copy_tty_state()). */
207 xfree (tinfo
->ttystate
);
208 tinfo
->ttystate
= serial_get_tty_state (stdin_serial
);
210 #ifdef PROCESS_GROUP_TYPE
211 tinfo
->process_group
= pgrp
;
214 /* Make sure that next time we call terminal_inferior (which will be
215 before the program runs, as it needs to be), we install the new
217 terminal_is_ours
= 1;
221 /* Save the terminal settings again. This is necessary for the TUI
222 when it switches to TUI or non-TUI mode; curses changes the terminal
223 and gdb must be able to restore it correctly. */
226 terminal_save_ours (void)
228 if (gdb_has_a_terminal ())
230 /* We could just as well copy our_ttystate (if we felt like adding
231 a new function serial_copy_tty_state). */
232 xfree (our_terminal_info
.ttystate
);
233 our_terminal_info
.ttystate
= serial_get_tty_state (stdin_serial
);
238 terminal_init_inferior (void)
240 #ifdef PROCESS_GROUP_TYPE
241 /* This is for Lynx, and should be cleaned up by having Lynx be a separate
242 debugging target with a version of target_terminal_init_inferior which
243 passes in the process group to a generic routine which does all the work
244 (and the non-threaded child_terminal_init_inferior can just pass in
245 inferior_ptid to the same routine). */
246 /* We assume INFERIOR_PID is also the child's process group. */
247 terminal_init_inferior_with_pgrp (PIDGET (inferior_ptid
));
248 #endif /* PROCESS_GROUP_TYPE */
251 /* Put the inferior's terminal settings into effect.
252 This is preparation for starting or resuming the inferior. */
255 terminal_inferior (void)
257 struct inferior
*inf
;
258 struct terminal_info
*tinfo
;
260 if (!terminal_is_ours
)
263 inf
= current_inferior ();
264 tinfo
= get_inflow_inferior_data (inf
);
266 if (gdb_has_a_terminal ()
267 && tinfo
->ttystate
!= NULL
268 && tinfo
->run_terminal
== NULL
)
273 /* Is there a reason this is being done twice? It happens both
274 places we use F_SETFL, so I'm inclined to think perhaps there
275 is some reason, however perverse. Perhaps not though... */
276 result
= fcntl (0, F_SETFL
, tinfo
->tflags
);
277 result
= fcntl (0, F_SETFL
, tinfo
->tflags
);
278 OOPSY ("fcntl F_SETFL");
281 /* Because we were careful to not change in or out of raw mode in
282 terminal_ours, we will not change in our out of raw mode with
283 this call, so we don't flush any input. */
284 result
= serial_set_tty_state (stdin_serial
,
286 OOPSY ("setting tty state");
290 sigint_ours
= (void (*)()) signal (SIGINT
, SIG_IGN
);
292 sigquit_ours
= (void (*)()) signal (SIGQUIT
, SIG_IGN
);
296 /* If attach_flag is set, we don't know whether we are sharing a
297 terminal with the inferior or not. (attaching a process
298 without a terminal is one case where we do not; attaching a
299 process which we ran from the same shell as GDB via `&' is
300 one case where we do, I think (but perhaps this is not
301 `sharing' in the sense that we need to save and restore tty
302 state)). I don't know if there is any way to tell whether we
303 are sharing a terminal. So what we do is to go through all
304 the saving and restoring of the tty state, but ignore errors
305 setting the process group, which will happen if we are not
306 sharing a terminal). */
311 result
= tcsetpgrp (0, tinfo
->process_group
);
312 if (!inf
->attach_flag
)
317 result
= ioctl (0, TIOCSPGRP
, &tinfo
->process_group
);
318 if (!inf
->attach_flag
)
324 terminal_is_ours
= 0;
327 /* Put some of our terminal settings into effect,
328 enough to get proper results from our output,
329 but do not change into or out of RAW mode
330 so that no input is discarded.
332 After doing this, either terminal_ours or terminal_inferior
333 should be called to get back to a normal state of affairs. */
336 terminal_ours_for_output (void)
341 /* Put our terminal settings into effect.
342 First record the inferior's terminal settings
343 so they can be restored properly later. */
351 /* output_only is not used, and should not be used unless we introduce
352 separate terminal_is_ours and terminal_is_ours_for_output
356 terminal_ours_1 (int output_only
)
358 struct inferior
*inf
;
359 struct terminal_info
*tinfo
;
361 if (terminal_is_ours
)
364 terminal_is_ours
= 1;
366 /* Checking inferior->run_terminal is necessary so that
367 if GDB is running in the background, it won't block trying
368 to do the ioctl()'s below. Checking gdb_has_a_terminal
369 avoids attempting all the ioctl's when running in batch. */
371 inf
= current_inferior ();
372 tinfo
= get_inflow_inferior_data (inf
);
374 if (tinfo
->run_terminal
!= NULL
|| gdb_has_a_terminal () == 0)
379 /* Ignore this signal since it will happen when we try to set the
381 void (*osigttou
) () = NULL
;
387 osigttou
= (void (*)()) signal (SIGTTOU
, SIG_IGN
);
390 xfree (tinfo
->ttystate
);
391 tinfo
->ttystate
= serial_get_tty_state (stdin_serial
);
393 #ifdef PROCESS_GROUP_TYPE
394 if (!inf
->attach_flag
)
395 /* If setpgrp failed in terminal_inferior, this would give us
396 our process group instead of the inferior's. See
397 terminal_inferior for details. */
398 tinfo
->process_group
= gdb_getpgrp ();
401 /* Here we used to set ICANON in our ttystate, but I believe this
402 was an artifact from before when we used readline. Readline sets
403 the tty state when it needs to.
404 FIXME-maybe: However, query() expects non-raw mode and doesn't
405 use readline. Maybe query should use readline (on the other hand,
406 this only matters for HAVE_SGTTY, not termio or termios, I think). */
408 /* Set tty state to our_ttystate. We don't change in our out of raw
409 mode, to avoid flushing input. We need to do the same thing
410 regardless of output_only, because we don't have separate
411 terminal_is_ours and terminal_is_ours_for_output flags. It's OK,
412 though, since readline will deal with raw mode when/if it needs to.
415 serial_noflush_set_tty_state (stdin_serial
, our_terminal_info
.ttystate
,
421 result
= tcsetpgrp (0, our_terminal_info
.process_group
);
423 /* This fails on Ultrix with EINVAL if you run the testsuite
424 in the background with nohup, and then log out. GDB never
425 used to check for an error here, so perhaps there are other
426 such situations as well. */
428 fprintf_unfiltered (gdb_stderr
,
429 "[tcsetpgrp failed in terminal_ours: %s]\n",
430 safe_strerror (errno
));
435 result
= ioctl (0, TIOCSPGRP
, &our_terminal_info
.process_group
);
441 signal (SIGTTOU
, osigttou
);
446 signal (SIGINT
, sigint_ours
);
448 signal (SIGQUIT
, sigquit_ours
);
453 tinfo
->tflags
= fcntl (0, F_GETFL
, 0);
455 /* Is there a reason this is being done twice? It happens both
456 places we use F_SETFL, so I'm inclined to think perhaps there
457 is some reason, however perverse. Perhaps not though... */
458 result
= fcntl (0, F_SETFL
, our_terminal_info
.tflags
);
459 result
= fcntl (0, F_SETFL
, our_terminal_info
.tflags
);
464 /* Per-inferior data key. */
465 static const struct inferior_data
*inflow_inferior_data
;
468 inflow_inferior_data_cleanup (struct inferior
*inf
, void *arg
)
470 struct terminal_info
*info
;
472 info
= inferior_data (inf
, inflow_inferior_data
);
475 xfree (info
->run_terminal
);
480 /* Get the current svr4 data. If none is found yet, add it now. This
481 function always returns a valid object. */
483 static struct terminal_info
*
484 get_inflow_inferior_data (struct inferior
*inf
)
486 struct terminal_info
*info
;
488 info
= inferior_data (inf
, inflow_inferior_data
);
491 info
= XZALLOC (struct terminal_info
);
492 set_inferior_data (inf
, inflow_inferior_data
, info
);
498 /* This is a "inferior_exit" observer. Releases the TERMINAL_INFO member
499 of the inferior structure. This field is private to inflow.c, and
500 its type is opaque to the rest of GDB. PID is the target pid of
501 the inferior that is about to be removed from the inferior
505 inflow_inferior_exit (struct inferior
*inf
)
507 struct terminal_info
*info
;
509 info
= inferior_data (inf
, inflow_inferior_data
);
512 xfree (info
->run_terminal
);
514 set_inferior_data (inf
, inflow_inferior_data
, NULL
);
519 copy_terminal_info (struct inferior
*to
, struct inferior
*from
)
521 struct terminal_info
*tinfo_to
, *tinfo_from
;
523 tinfo_to
= get_inflow_inferior_data (to
);
524 tinfo_from
= get_inflow_inferior_data (from
);
525 *tinfo_to
= *tinfo_from
;
526 if (tinfo_from
->run_terminal
)
527 tinfo_to
->run_terminal
528 = xstrdup (tinfo_from
->run_terminal
);
532 term_info (char *arg
, int from_tty
)
534 target_terminal_info (arg
, from_tty
);
538 child_terminal_info (char *args
, int from_tty
)
540 struct inferior
*inf
;
541 struct terminal_info
*tinfo
;
543 if (!gdb_has_a_terminal ())
545 printf_filtered (_("This GDB does not control a terminal.\n"));
549 if (ptid_equal (inferior_ptid
, null_ptid
))
552 inf
= current_inferior ();
553 tinfo
= get_inflow_inferior_data (inf
);
555 printf_filtered (_("Inferior's terminal status "
556 "(currently saved by GDB):\n"));
558 /* First the fcntl flags. */
562 flags
= tinfo
->tflags
;
564 printf_filtered ("File descriptor flags = ");
567 #define O_ACCMODE (O_RDONLY | O_WRONLY | O_RDWR)
569 /* (O_ACCMODE) parens are to avoid Ultrix header file bug */
570 switch (flags
& (O_ACCMODE
))
573 printf_filtered ("O_RDONLY");
576 printf_filtered ("O_WRONLY");
579 printf_filtered ("O_RDWR");
582 flags
&= ~(O_ACCMODE
);
585 if (flags
& O_NONBLOCK
)
586 printf_filtered (" | O_NONBLOCK");
587 flags
&= ~O_NONBLOCK
;
590 #if defined (O_NDELAY)
591 /* If O_NDELAY and O_NONBLOCK are defined to the same thing, we will
592 print it as O_NONBLOCK, which is good cause that is what POSIX
593 has, and the flag will already be cleared by the time we get here. */
594 if (flags
& O_NDELAY
)
595 printf_filtered (" | O_NDELAY");
599 if (flags
& O_APPEND
)
600 printf_filtered (" | O_APPEND");
603 #if defined (O_BINARY)
604 if (flags
& O_BINARY
)
605 printf_filtered (" | O_BINARY");
610 printf_filtered (" | 0x%x", flags
);
611 printf_filtered ("\n");
614 #ifdef PROCESS_GROUP_TYPE
615 printf_filtered ("Process group = %d\n", (int) tinfo
->process_group
);
618 serial_print_tty_state (stdin_serial
, tinfo
->ttystate
, gdb_stdout
);
621 /* NEW_TTY_PREFORK is called before forking a new child process,
622 so we can record the state of ttys in the child to be formed.
623 TTYNAME is null if we are to share the terminal with gdb;
624 or points to a string containing the name of the desired tty.
626 NEW_TTY is called in new child processes under Unix, which will
627 become debugger target processes. This actually switches to
628 the terminal specified in the NEW_TTY_PREFORK call. */
631 new_tty_prefork (const char *ttyname
)
633 /* Save the name for later, for determining whether we and the child
634 are sharing a tty. */
635 inferior_thisrun_terminal
= ttyname
;
638 #if !defined(__GO32__) && !defined(_WIN32)
639 /* If RESULT, assumed to be the return value from a system call, is
640 negative, print the error message indicated by errno and exit.
641 MSG should identify the operation that failed. */
643 check_syscall (const char *msg
, int result
)
647 print_sys_errmsg (msg
, errno
);
658 if (inferior_thisrun_terminal
== 0)
660 #if !defined(__GO32__) && !defined(_WIN32)
662 /* Disconnect the child process from our controlling terminal. On some
663 systems (SVR4 for example), this may cause a SIGTTOU, so temporarily
665 tty
= open ("/dev/tty", O_RDWR
);
670 osigttou
= (void (*)()) signal (SIGTTOU
, SIG_IGN
);
671 ioctl (tty
, TIOCNOTTY
, 0);
673 signal (SIGTTOU
, osigttou
);
677 /* Now open the specified new terminal. */
678 tty
= open (inferior_thisrun_terminal
, O_RDWR
| O_NOCTTY
);
679 check_syscall (inferior_thisrun_terminal
, tty
);
681 /* Avoid use of dup2; doesn't exist on all systems. */
685 check_syscall ("dup'ing tty into fd 0", dup (tty
));
690 check_syscall ("dup'ing tty into fd 1", dup (tty
));
695 check_syscall ("dup'ing tty into fd 2", dup (tty
));
699 /* Make tty our new controlling terminal. */
700 if (ioctl (tty
, TIOCSCTTY
, 0) == -1)
701 /* Mention GDB in warning because it will appear in the inferior's
702 terminal instead of GDB's. */
703 warning ("GDB: Failed to set controlling terminal: %s",
704 safe_strerror (errno
));
709 #endif /* !go32 && !win32 */
712 /* NEW_TTY_POSTFORK is called after forking a new child process, and
713 adding it to the inferior table, to store the TTYNAME being used by
714 the child, or null if it sharing the terminal with gdb. */
717 new_tty_postfork (void)
719 /* Save the name for later, for determining whether we and the child
720 are sharing a tty. */
722 if (inferior_thisrun_terminal
)
724 struct inferior
*inf
= current_inferior ();
725 struct terminal_info
*tinfo
= get_inflow_inferior_data (inf
);
727 tinfo
->run_terminal
= xstrdup (inferior_thisrun_terminal
);
730 inferior_thisrun_terminal
= NULL
;
734 /* Call set_sigint_trap when you need to pass a signal on to an attached
735 process when handling SIGINT */
738 pass_signal (int signo
)
741 kill (PIDGET (inferior_ptid
), SIGINT
);
745 static void (*osig
) ();
749 set_sigint_trap (void)
751 struct inferior
*inf
= current_inferior ();
752 struct terminal_info
*tinfo
= get_inflow_inferior_data (inf
);
754 if (inf
->attach_flag
|| tinfo
->run_terminal
)
756 osig
= (void (*)()) signal (SIGINT
, pass_signal
);
764 clear_sigint_trap (void)
768 signal (SIGINT
, osig
);
774 /* Create a new session if the inferior will run in a different tty.
775 A session is UNIX's way of grouping processes that share a controlling
776 terminal, so a new one is needed if the inferior terminal will be
777 different from GDB's.
779 Returns the session id of the new session, 0 if no session was created
780 or -1 if an error occurred. */
782 create_tty_session (void)
787 if (!job_control
|| inferior_thisrun_terminal
== 0)
792 warning ("Failed to create new terminal session: setsid: %s",
793 safe_strerror (errno
));
798 #endif /* HAVE_SETSID */
801 /* This is here because this is where we figure out whether we (probably)
802 have job control. Just using job_control only does part of it because
803 setpgid or setpgrp might not exist on a system without job control.
804 It might be considered misplaced (on the other hand, process groups and
805 job control are closely related to ttys).
807 For a more clean implementation, in libiberty, put a setpgid which merely
808 calls setpgrp and a setpgrp which does nothing (any system with job control
809 will have one or the other). */
817 #if defined (HAVE_TERMIOS) || defined (TIOCGPGRP)
819 /* The call setpgid (0, 0) is supposed to work and mean the same
820 thing as this, but on Ultrix 4.2A it fails with EPERM (and
821 setpgid (getpid (), getpid ()) succeeds). */
822 retval
= setpgid (getpid (), getpid ());
828 retval
= setpgrp (getpid (), getpid ());
830 #endif /* HAVE_SETPGRP */
831 #endif /* HAVE_SETPGID */
832 #endif /* defined (HAVE_TERMIOS) || defined (TIOCGPGRP) */
838 /* Get all the current tty settings (including whether we have a
839 tty at all!). We can't do this in _initialize_inflow because
840 serial_fdopen() won't work until the serial_ops_list is
841 initialized, but we don't want to do it lazily either, so
842 that we can guarantee stdin_serial is opened if there is
845 initialize_stdin_serial (void)
847 stdin_serial
= serial_fdopen (0);
851 _initialize_inflow (void)
853 add_info ("terminal", term_info
,
854 _("Print inferior's saved terminal status."));
856 terminal_is_ours
= 1;
858 /* OK, figure out whether we have job control. If neither termios nor
859 sgtty (i.e. termio or go32), leave job_control 0. */
861 #if defined (HAVE_TERMIOS)
862 /* Do all systems with termios have the POSIX way of identifying job
863 control? I hope so. */
864 #ifdef _POSIX_JOB_CONTROL
867 #ifdef _SC_JOB_CONTROL
868 job_control
= sysconf (_SC_JOB_CONTROL
);
870 job_control
= 0; /* have to assume the worst */
871 #endif /* _SC_JOB_CONTROL */
872 #endif /* _POSIX_JOB_CONTROL */
873 #endif /* HAVE_TERMIOS */
880 #endif /* TIOCGPGRP */
883 observer_attach_inferior_exit (inflow_inferior_exit
);
886 = register_inferior_data_with_cleanup (inflow_inferior_data_cleanup
);