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 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;
125 process_group
= tcgetpgrp (0);
128 process_group
= getpgrp ();
131 ioctl (0, TIOCGPGRP
, &process_group
);
133 return process_group
;
139 yes
, no
, have_not_checked
141 gdb_has_a_terminal_flag
= have_not_checked
;
143 /* Does GDB have a terminal (on stdin)? */
145 gdb_has_a_terminal (void)
147 switch (gdb_has_a_terminal_flag
)
153 case have_not_checked
:
154 /* Get all the current tty settings (including whether we have a
155 tty at all!). Can't do this in _initialize_inflow because
156 serial_fdopen() won't work until the serial_ops_list is
160 our_terminal_info
.tflags
= fcntl (0, F_GETFL
, 0);
163 gdb_has_a_terminal_flag
= no
;
164 if (stdin_serial
!= NULL
)
166 our_terminal_info
.ttystate
= serial_get_tty_state (stdin_serial
);
168 if (our_terminal_info
.ttystate
!= NULL
)
170 gdb_has_a_terminal_flag
= yes
;
171 #ifdef PROCESS_GROUP_TYPE
172 our_terminal_info
.process_group
= gdb_getpgrp ();
177 return gdb_has_a_terminal_flag
== yes
;
179 /* "Can't happen". */
184 /* Macro for printing errors from ioctl operations */
186 #define OOPSY(what) \
188 fprintf_unfiltered(gdb_stderr, "[%s failed in terminal_inferior: %s]\n", \
189 what, safe_strerror (errno))
191 static void terminal_ours_1 (int);
193 /* Initialize the terminal settings we record for the inferior,
194 before we actually run the inferior. */
197 terminal_init_inferior_with_pgrp (int pgrp
)
199 if (gdb_has_a_terminal ())
201 struct inferior
*inf
= current_inferior ();
202 struct terminal_info
*tinfo
= get_inflow_inferior_data (inf
);
204 /* We could just as well copy our_ttystate (if we felt like
205 adding a new function serial_copy_tty_state()). */
206 xfree (tinfo
->ttystate
);
207 tinfo
->ttystate
= serial_get_tty_state (stdin_serial
);
209 #ifdef PROCESS_GROUP_TYPE
210 tinfo
->process_group
= pgrp
;
213 /* Make sure that next time we call terminal_inferior (which will be
214 before the program runs, as it needs to be), we install the new
216 terminal_is_ours
= 1;
220 /* Save the terminal settings again. This is necessary for the TUI
221 when it switches to TUI or non-TUI mode; curses changes the terminal
222 and gdb must be able to restore it correctly. */
225 terminal_save_ours (void)
227 if (gdb_has_a_terminal ())
229 /* We could just as well copy our_ttystate (if we felt like adding
230 a new function serial_copy_tty_state). */
231 xfree (our_terminal_info
.ttystate
);
232 our_terminal_info
.ttystate
= serial_get_tty_state (stdin_serial
);
237 terminal_init_inferior (void)
239 #ifdef PROCESS_GROUP_TYPE
240 /* This is for Lynx, and should be cleaned up by having Lynx be a separate
241 debugging target with a version of target_terminal_init_inferior which
242 passes in the process group to a generic routine which does all the work
243 (and the non-threaded child_terminal_init_inferior can just pass in
244 inferior_ptid to the same routine). */
245 /* We assume INFERIOR_PID is also the child's process group. */
246 terminal_init_inferior_with_pgrp (PIDGET (inferior_ptid
));
247 #endif /* PROCESS_GROUP_TYPE */
250 /* Put the inferior's terminal settings into effect.
251 This is preparation for starting or resuming the inferior. */
254 terminal_inferior (void)
256 struct inferior
*inf
;
257 struct terminal_info
*tinfo
;
259 if (!terminal_is_ours
)
262 inf
= current_inferior ();
263 tinfo
= get_inflow_inferior_data (inf
);
265 if (gdb_has_a_terminal ()
266 && tinfo
->ttystate
!= NULL
267 && tinfo
->run_terminal
== NULL
)
272 /* Is there a reason this is being done twice? It happens both
273 places we use F_SETFL, so I'm inclined to think perhaps there
274 is some reason, however perverse. Perhaps not though... */
275 result
= fcntl (0, F_SETFL
, tinfo
->tflags
);
276 result
= fcntl (0, F_SETFL
, tinfo
->tflags
);
277 OOPSY ("fcntl F_SETFL");
280 /* Because we were careful to not change in or out of raw mode in
281 terminal_ours, we will not change in our out of raw mode with
282 this call, so we don't flush any input. */
283 result
= serial_set_tty_state (stdin_serial
,
285 OOPSY ("setting tty state");
289 sigint_ours
= (void (*)()) signal (SIGINT
, SIG_IGN
);
291 sigquit_ours
= (void (*)()) signal (SIGQUIT
, SIG_IGN
);
295 /* If attach_flag is set, we don't know whether we are sharing a
296 terminal with the inferior or not. (attaching a process
297 without a terminal is one case where we do not; attaching a
298 process which we ran from the same shell as GDB via `&' is
299 one case where we do, I think (but perhaps this is not
300 `sharing' in the sense that we need to save and restore tty
301 state)). I don't know if there is any way to tell whether we
302 are sharing a terminal. So what we do is to go through all
303 the saving and restoring of the tty state, but ignore errors
304 setting the process group, which will happen if we are not
305 sharing a terminal). */
310 result
= tcsetpgrp (0, tinfo
->process_group
);
311 if (!inf
->attach_flag
)
316 result
= ioctl (0, TIOCSPGRP
, &tinfo
->process_group
);
317 if (!inf
->attach_flag
)
323 terminal_is_ours
= 0;
326 /* Put some of our terminal settings into effect,
327 enough to get proper results from our output,
328 but do not change into or out of RAW mode
329 so that no input is discarded.
331 After doing this, either terminal_ours or terminal_inferior
332 should be called to get back to a normal state of affairs. */
335 terminal_ours_for_output (void)
340 /* Put our terminal settings into effect.
341 First record the inferior's terminal settings
342 so they can be restored properly later. */
350 /* output_only is not used, and should not be used unless we introduce
351 separate terminal_is_ours and terminal_is_ours_for_output
355 terminal_ours_1 (int output_only
)
357 struct inferior
*inf
;
358 struct terminal_info
*tinfo
;
360 if (terminal_is_ours
)
363 terminal_is_ours
= 1;
365 /* Checking inferior->run_terminal is necessary so that
366 if GDB is running in the background, it won't block trying
367 to do the ioctl()'s below. Checking gdb_has_a_terminal
368 avoids attempting all the ioctl's when running in batch. */
370 inf
= current_inferior ();
371 tinfo
= get_inflow_inferior_data (inf
);
373 if (tinfo
->run_terminal
!= NULL
|| gdb_has_a_terminal () == 0)
378 /* Ignore this signal since it will happen when we try to set the
380 void (*osigttou
) () = NULL
;
386 osigttou
= (void (*)()) signal (SIGTTOU
, SIG_IGN
);
389 xfree (tinfo
->ttystate
);
390 tinfo
->ttystate
= serial_get_tty_state (stdin_serial
);
392 #ifdef PROCESS_GROUP_TYPE
393 if (!inf
->attach_flag
)
394 /* If setpgrp failed in terminal_inferior, this would give us
395 our process group instead of the inferior's. See
396 terminal_inferior for details. */
397 tinfo
->process_group
= gdb_getpgrp ();
400 /* Here we used to set ICANON in our ttystate, but I believe this
401 was an artifact from before when we used readline. Readline sets
402 the tty state when it needs to.
403 FIXME-maybe: However, query() expects non-raw mode and doesn't
404 use readline. Maybe query should use readline (on the other hand,
405 this only matters for HAVE_SGTTY, not termio or termios, I think). */
407 /* Set tty state to our_ttystate. We don't change in our out of raw
408 mode, to avoid flushing input. We need to do the same thing
409 regardless of output_only, because we don't have separate
410 terminal_is_ours and terminal_is_ours_for_output flags. It's OK,
411 though, since readline will deal with raw mode when/if it needs to.
414 serial_noflush_set_tty_state (stdin_serial
, our_terminal_info
.ttystate
,
420 result
= tcsetpgrp (0, our_terminal_info
.process_group
);
422 /* This fails on Ultrix with EINVAL if you run the testsuite
423 in the background with nohup, and then log out. GDB never
424 used to check for an error here, so perhaps there are other
425 such situations as well. */
427 fprintf_unfiltered (gdb_stderr
, "[tcsetpgrp failed in terminal_ours: %s]\n",
428 safe_strerror (errno
));
433 result
= ioctl (0, TIOCSPGRP
, &our_terminal_info
.process_group
);
439 signal (SIGTTOU
, osigttou
);
444 signal (SIGINT
, sigint_ours
);
446 signal (SIGQUIT
, sigquit_ours
);
451 tinfo
->tflags
= fcntl (0, F_GETFL
, 0);
453 /* Is there a reason this is being done twice? It happens both
454 places we use F_SETFL, so I'm inclined to think perhaps there
455 is some reason, however perverse. Perhaps not though... */
456 result
= fcntl (0, F_SETFL
, our_terminal_info
.tflags
);
457 result
= fcntl (0, F_SETFL
, our_terminal_info
.tflags
);
462 /* Per-inferior data key. */
463 static const struct inferior_data
*inflow_inferior_data
;
466 inflow_inferior_data_cleanup (struct inferior
*inf
, void *arg
)
468 struct terminal_info
*info
;
470 info
= inferior_data (inf
, inflow_inferior_data
);
473 xfree (info
->run_terminal
);
478 /* Get the current svr4 data. If none is found yet, add it now. This
479 function always returns a valid object. */
481 static struct terminal_info
*
482 get_inflow_inferior_data (struct inferior
*inf
)
484 struct terminal_info
*info
;
486 info
= inferior_data (inf
, inflow_inferior_data
);
489 info
= XZALLOC (struct terminal_info
);
490 set_inferior_data (inf
, inflow_inferior_data
, info
);
496 /* This is a "inferior_exit" observer. Releases the TERMINAL_INFO member
497 of the inferior structure. This field is private to inflow.c, and
498 its type is opaque to the rest of GDB. PID is the target pid of
499 the inferior that is about to be removed from the inferior
503 inflow_inferior_exit (int pid
)
505 struct inferior
*inf
= find_inferior_pid (pid
);
506 struct terminal_info
*info
;
508 info
= inferior_data (inf
, inflow_inferior_data
);
511 xfree (info
->run_terminal
);
513 set_inferior_data (inf
, inflow_inferior_data
, NULL
);
518 copy_terminal_info (struct inferior
*to
, struct inferior
*from
)
520 struct terminal_info
*tinfo_to
, *tinfo_from
;
522 tinfo_to
= get_inflow_inferior_data (to
);
523 tinfo_from
= get_inflow_inferior_data (from
);
524 *tinfo_to
= *tinfo_from
;
525 if (tinfo_from
->run_terminal
)
526 tinfo_to
->run_terminal
527 = xstrdup (tinfo_from
->run_terminal
);
531 term_info (char *arg
, int from_tty
)
533 target_terminal_info (arg
, from_tty
);
537 child_terminal_info (char *args
, int from_tty
)
539 struct inferior
*inf
;
540 struct terminal_info
*tinfo
;
542 if (!gdb_has_a_terminal ())
544 printf_filtered (_("This GDB does not control a terminal.\n"));
548 if (ptid_equal (inferior_ptid
, null_ptid
))
551 inf
= current_inferior ();
552 tinfo
= get_inflow_inferior_data (inf
);
554 printf_filtered (_("Inferior's terminal status (currently saved by GDB):\n"));
556 /* First the fcntl flags. */
560 flags
= tinfo
->tflags
;
562 printf_filtered ("File descriptor flags = ");
565 #define O_ACCMODE (O_RDONLY | O_WRONLY | O_RDWR)
567 /* (O_ACCMODE) parens are to avoid Ultrix header file bug */
568 switch (flags
& (O_ACCMODE
))
571 printf_filtered ("O_RDONLY");
574 printf_filtered ("O_WRONLY");
577 printf_filtered ("O_RDWR");
580 flags
&= ~(O_ACCMODE
);
583 if (flags
& O_NONBLOCK
)
584 printf_filtered (" | O_NONBLOCK");
585 flags
&= ~O_NONBLOCK
;
588 #if defined (O_NDELAY)
589 /* If O_NDELAY and O_NONBLOCK are defined to the same thing, we will
590 print it as O_NONBLOCK, which is good cause that is what POSIX
591 has, and the flag will already be cleared by the time we get here. */
592 if (flags
& O_NDELAY
)
593 printf_filtered (" | O_NDELAY");
597 if (flags
& O_APPEND
)
598 printf_filtered (" | O_APPEND");
601 #if defined (O_BINARY)
602 if (flags
& O_BINARY
)
603 printf_filtered (" | O_BINARY");
608 printf_filtered (" | 0x%x", flags
);
609 printf_filtered ("\n");
612 #ifdef PROCESS_GROUP_TYPE
613 printf_filtered ("Process group = %d\n", (int) tinfo
->process_group
);
616 serial_print_tty_state (stdin_serial
, tinfo
->ttystate
, gdb_stdout
);
619 /* NEW_TTY_PREFORK is called before forking a new child process,
620 so we can record the state of ttys in the child to be formed.
621 TTYNAME is null if we are to share the terminal with gdb;
622 or points to a string containing the name of the desired tty.
624 NEW_TTY is called in new child processes under Unix, which will
625 become debugger target processes. This actually switches to
626 the terminal specified in the NEW_TTY_PREFORK call. */
629 new_tty_prefork (const char *ttyname
)
631 /* Save the name for later, for determining whether we and the child
632 are sharing a tty. */
633 inferior_thisrun_terminal
= ttyname
;
636 #if !defined(__GO32__) && !defined(_WIN32)
637 /* If RESULT, assumed to be the return value from a system call, is
638 negative, print the error message indicated by errno and exit.
639 MSG should identify the operation that failed. */
641 check_syscall (const char *msg
, int result
)
645 print_sys_errmsg (msg
, errno
);
656 if (inferior_thisrun_terminal
== 0)
658 #if !defined(__GO32__) && !defined(_WIN32)
660 /* Disconnect the child process from our controlling terminal. On some
661 systems (SVR4 for example), this may cause a SIGTTOU, so temporarily
663 tty
= open ("/dev/tty", O_RDWR
);
668 osigttou
= (void (*)()) signal (SIGTTOU
, SIG_IGN
);
669 ioctl (tty
, TIOCNOTTY
, 0);
671 signal (SIGTTOU
, osigttou
);
675 /* Now open the specified new terminal. */
676 tty
= open (inferior_thisrun_terminal
, O_RDWR
| O_NOCTTY
);
677 check_syscall (inferior_thisrun_terminal
, tty
);
679 /* Avoid use of dup2; doesn't exist on all systems. */
683 check_syscall ("dup'ing tty into fd 0", dup (tty
));
688 check_syscall ("dup'ing tty into fd 1", dup (tty
));
693 check_syscall ("dup'ing tty into fd 2", dup (tty
));
697 /* Make tty our new controlling terminal. */
698 if (ioctl (tty
, TIOCSCTTY
, 0) == -1)
699 /* Mention GDB in warning because it will appear in the inferior's
700 terminal instead of GDB's. */
701 warning ("GDB: Failed to set controlling terminal: %s",
702 safe_strerror (errno
));
707 #endif /* !go32 && !win32 */
710 /* NEW_TTY_POSTFORK is called after forking a new child process, and
711 adding it to the inferior table, to store the TTYNAME being used by
712 the child, or null if it sharing the terminal with gdb. */
715 new_tty_postfork (void)
717 /* Save the name for later, for determining whether we and the child
718 are sharing a tty. */
720 if (inferior_thisrun_terminal
)
722 struct inferior
*inf
= current_inferior ();
723 struct terminal_info
*tinfo
= get_inflow_inferior_data (inf
);
725 tinfo
->run_terminal
= xstrdup (inferior_thisrun_terminal
);
728 inferior_thisrun_terminal
= NULL
;
732 /* Call set_sigint_trap when you need to pass a signal on to an attached
733 process when handling SIGINT */
736 pass_signal (int signo
)
739 kill (PIDGET (inferior_ptid
), SIGINT
);
743 static void (*osig
) ();
747 set_sigint_trap (void)
749 struct inferior
*inf
= current_inferior ();
750 struct terminal_info
*tinfo
= get_inflow_inferior_data (inf
);
752 if (inf
->attach_flag
|| tinfo
->run_terminal
)
754 osig
= (void (*)()) signal (SIGINT
, pass_signal
);
762 clear_sigint_trap (void)
766 signal (SIGINT
, osig
);
772 /* Create a new session if the inferior will run in a different tty.
773 A session is UNIX's way of grouping processes that share a controlling
774 terminal, so a new one is needed if the inferior terminal will be
775 different from GDB's.
777 Returns the session id of the new session, 0 if no session was created
778 or -1 if an error occurred. */
780 create_tty_session (void)
785 if (!job_control
|| inferior_thisrun_terminal
== 0)
790 warning ("Failed to create new terminal session: setsid: %s",
791 safe_strerror (errno
));
796 #endif /* HAVE_SETSID */
799 /* This is here because this is where we figure out whether we (probably)
800 have job control. Just using job_control only does part of it because
801 setpgid or setpgrp might not exist on a system without job control.
802 It might be considered misplaced (on the other hand, process groups and
803 job control are closely related to ttys).
805 For a more clean implementation, in libiberty, put a setpgid which merely
806 calls setpgrp and a setpgrp which does nothing (any system with job control
807 will have one or the other). */
815 #if defined (HAVE_TERMIOS) || defined (TIOCGPGRP)
817 /* The call setpgid (0, 0) is supposed to work and mean the same
818 thing as this, but on Ultrix 4.2A it fails with EPERM (and
819 setpgid (getpid (), getpid ()) succeeds). */
820 retval
= setpgid (getpid (), getpid ());
826 retval
= setpgrp (getpid (), getpid ());
828 #endif /* HAVE_SETPGRP */
829 #endif /* HAVE_SETPGID */
830 #endif /* defined (HAVE_TERMIOS) || defined (TIOCGPGRP) */
836 /* Get all the current tty settings (including whether we have a
837 tty at all!). We can't do this in _initialize_inflow because
838 serial_fdopen() won't work until the serial_ops_list is
839 initialized, but we don't want to do it lazily either, so
840 that we can guarantee stdin_serial is opened if there is
843 initialize_stdin_serial (void)
845 stdin_serial
= serial_fdopen (0);
849 _initialize_inflow (void)
851 add_info ("terminal", term_info
,
852 _("Print inferior's saved terminal status."));
854 terminal_is_ours
= 1;
856 /* OK, figure out whether we have job control. If neither termios nor
857 sgtty (i.e. termio or go32), leave job_control 0. */
859 #if defined (HAVE_TERMIOS)
860 /* Do all systems with termios have the POSIX way of identifying job
861 control? I hope so. */
862 #ifdef _POSIX_JOB_CONTROL
865 #ifdef _SC_JOB_CONTROL
866 job_control
= sysconf (_SC_JOB_CONTROL
);
868 job_control
= 0; /* have to assume the worst */
869 #endif /* _SC_JOB_CONTROL */
870 #endif /* _POSIX_JOB_CONTROL */
871 #endif /* HAVE_TERMIOS */
878 #endif /* TIOCGPGRP */
881 observer_attach_inferior_exit (inflow_inferior_exit
);
884 = register_inferior_data_with_cleanup (inflow_inferior_data_cleanup
);