1 /* Low level interface to ptrace, for GDB when running under Unix.
2 Copyright (C) 1986-2017 Free Software Foundation, Inc.
4 This file is part of GDB.
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 3 of the License, or
9 (at your option) any later version.
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program. If not, see <http://www.gnu.org/licenses/>. */
26 #include "gdbthread.h"
30 #include "gdb_select.h"
37 #include "job-control.h"
39 #ifdef HAVE_SYS_IOCTL_H
40 #include <sys/ioctl.h>
47 static void pass_signal (int);
49 static void child_terminal_ours_1 (int);
51 /* Record terminal status separately for debugger and inferior. */
53 static struct serial
*stdin_serial
;
55 /* Terminal related info we need to keep track of. Each inferior
56 holds an instance of this structure --- we save it whenever the
57 corresponding inferior stops, and restore it to the foreground
58 inferior when it resumes. */
61 /* The name of the tty (from the `tty' command) that we gave to the
62 inferior when it was started. */
65 /* TTY state. We save it whenever the inferior stops, and restore
66 it when it resumes. */
67 serial_ttystate ttystate
;
70 /* Process group. Saved and restored just like ttystate. */
74 /* fcntl flags. Saved and restored just like ttystate. */
78 /* Our own tty state, which we restore every time we need to deal with
79 the terminal. This is set once, when GDB first starts, and then
80 whenever we enter/leave TUI mode (gdb_save_tty_state). The
81 settings of flags which readline saves and restores are
83 static struct terminal_info our_terminal_info
;
85 /* Snapshot of the initial tty state taken during initialization of
86 GDB, before readline/ncurses have had a chance to change it. This
87 is used as the initial tty state given to each new spawned
88 inferior. Unlike our_terminal_info, this is only ever set
90 static serial_ttystate initial_gdb_ttystate
;
92 static struct terminal_info
*get_inflow_inferior_data (struct inferior
*);
96 /* Return the process group of the current inferior. */
99 inferior_process_group (void)
101 return get_inflow_inferior_data (current_inferior ())->process_group
;
105 /* While the inferior is running, we want SIGINT and SIGQUIT to go to the
106 inferior only. If we have job control, that takes care of it. If not,
107 we save our handlers in these two variables and set SIGINT and SIGQUIT
110 static sighandler_t sigint_ours
;
111 static sighandler_t sigquit_ours
;
113 /* The name of the tty (from the `tty' command) that we're giving to
114 the inferior when starting it up. This is only (and should only
115 be) used as a transient global by new_tty_prefork,
116 create_tty_session, new_tty and new_tty_postfork, all called from
117 fork_inferior, while forking a new child. */
118 static const char *inferior_thisrun_terminal
;
120 /* Nonzero if our terminal settings are in effect. Zero if the
121 inferior's settings are in effect. Ignored if !gdb_has_a_terminal
124 int terminal_is_ours
;
126 /* See terminal.h. */
129 set_initial_gdb_ttystate (void)
131 /* Note we can't do any of this in _initialize_inflow because at
132 that point stdin_serial has not been created yet. */
134 initial_gdb_ttystate
= serial_get_tty_state (stdin_serial
);
136 if (initial_gdb_ttystate
!= NULL
)
138 our_terminal_info
.ttystate
139 = serial_copy_tty_state (stdin_serial
, initial_gdb_ttystate
);
141 our_terminal_info
.tflags
= fcntl (0, F_GETFL
, 0);
143 #ifdef HAVE_TERMIOS_H
144 our_terminal_info
.process_group
= tcgetpgrp (0);
149 /* Does GDB have a terminal (on stdin)? */
152 gdb_has_a_terminal (void)
154 return initial_gdb_ttystate
!= NULL
;
157 /* Macro for printing errors from ioctl operations */
159 #define OOPSY(what) \
161 fprintf_unfiltered(gdb_stderr, "[%s failed in terminal_inferior: %s]\n", \
162 what, safe_strerror (errno))
164 /* Initialize the terminal settings we record for the inferior,
165 before we actually run the inferior. */
168 child_terminal_init_with_pgrp (int pgrp
)
170 struct inferior
*inf
= current_inferior ();
171 struct terminal_info
*tinfo
= get_inflow_inferior_data (inf
);
173 #ifdef HAVE_TERMIOS_H
174 /* Store the process group even without a terminal as it is used not
175 only to reset the tty foreground process group, but also to
176 interrupt the inferior. */
177 tinfo
->process_group
= pgrp
;
180 if (gdb_has_a_terminal ())
182 xfree (tinfo
->ttystate
);
183 tinfo
->ttystate
= serial_copy_tty_state (stdin_serial
,
184 initial_gdb_ttystate
);
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
189 terminal_is_ours
= 1;
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. */
198 gdb_save_tty_state (void)
200 if (gdb_has_a_terminal ())
202 xfree (our_terminal_info
.ttystate
);
203 our_terminal_info
.ttystate
= serial_get_tty_state (stdin_serial
);
208 child_terminal_init (struct target_ops
*self
)
210 #ifdef HAVE_TERMIOS_H
211 /* This is for Lynx, and should be cleaned up by having Lynx be a
212 separate debugging target with a version of target_terminal::init
213 which passes in the process group to a generic routine which does
214 all the work (and the non-threaded child_terminal_init can just
215 pass in inferior_ptid to the same routine). */
216 /* We assume INFERIOR_PID is also the child's process group. */
217 child_terminal_init_with_pgrp (ptid_get_pid (inferior_ptid
));
218 #endif /* HAVE_TERMIOS_H */
221 /* Put the inferior's terminal settings into effect.
222 This is preparation for starting or resuming the inferior.
224 N.B. Targets that want to use this with async support must build that
225 support on top of this (e.g., the caller still needs to remove stdin
226 from the event loop). E.g., see linux_nat_terminal_inferior. */
229 child_terminal_inferior (struct target_ops
*self
)
231 struct inferior
*inf
;
232 struct terminal_info
*tinfo
;
234 if (!terminal_is_ours
)
237 inf
= current_inferior ();
238 tinfo
= get_inflow_inferior_data (inf
);
240 if (gdb_has_a_terminal ()
241 && tinfo
->ttystate
!= NULL
242 && tinfo
->run_terminal
== NULL
)
247 result
= fcntl (0, F_SETFL
, tinfo
->tflags
);
248 OOPSY ("fcntl F_SETFL");
251 result
= serial_set_tty_state (stdin_serial
, tinfo
->ttystate
);
252 OOPSY ("setting tty state");
256 sigint_ours
= signal (SIGINT
, SIG_IGN
);
258 sigquit_ours
= signal (SIGQUIT
, SIG_IGN
);
262 /* If attach_flag is set, we don't know whether we are sharing a
263 terminal with the inferior or not. (attaching a process
264 without a terminal is one case where we do not; attaching a
265 process which we ran from the same shell as GDB via `&' is
266 one case where we do, I think (but perhaps this is not
267 `sharing' in the sense that we need to save and restore tty
268 state)). I don't know if there is any way to tell whether we
269 are sharing a terminal. So what we do is to go through all
270 the saving and restoring of the tty state, but ignore errors
271 setting the process group, which will happen if we are not
272 sharing a terminal). */
276 #ifdef HAVE_TERMIOS_H
277 result
= tcsetpgrp (0, tinfo
->process_group
);
278 if (!inf
->attach_flag
)
283 terminal_is_ours
= 0;
286 /* Put some of our terminal settings into effect,
287 enough to get proper results from our output,
288 but do not change into or out of RAW mode
289 so that no input is discarded.
291 After doing this, either terminal_ours or terminal_inferior
292 should be called to get back to a normal state of affairs.
294 N.B. The implementation is (currently) no different than
295 child_terminal_ours. See child_terminal_ours_1. */
298 child_terminal_ours_for_output (struct target_ops
*self
)
300 child_terminal_ours_1 (1);
303 /* Put our terminal settings into effect.
304 First record the inferior's terminal settings
305 so they can be restored properly later.
307 N.B. Targets that want to use this with async support must build that
308 support on top of this (e.g., the caller still needs to add stdin to the
309 event loop). E.g., see linux_nat_terminal_ours. */
312 child_terminal_ours (struct target_ops
*self
)
314 child_terminal_ours_1 (0);
317 /* output_only is not used, and should not be used unless we introduce
318 separate terminal_is_ours and terminal_is_ours_for_output
322 child_terminal_ours_1 (int output_only
)
324 struct inferior
*inf
;
325 struct terminal_info
*tinfo
;
327 if (terminal_is_ours
)
330 terminal_is_ours
= 1;
332 /* Checking inferior->run_terminal is necessary so that
333 if GDB is running in the background, it won't block trying
334 to do the ioctl()'s below. Checking gdb_has_a_terminal
335 avoids attempting all the ioctl's when running in batch. */
337 inf
= current_inferior ();
338 tinfo
= get_inflow_inferior_data (inf
);
340 if (tinfo
->run_terminal
!= NULL
|| gdb_has_a_terminal () == 0)
345 /* Ignore this signal since it will happen when we try to set the
347 sighandler_t osigttou
= NULL
;
349 int result ATTRIBUTE_UNUSED
;
353 osigttou
= signal (SIGTTOU
, SIG_IGN
);
356 xfree (tinfo
->ttystate
);
357 tinfo
->ttystate
= serial_get_tty_state (stdin_serial
);
359 #ifdef HAVE_TERMIOS_H
360 if (!inf
->attach_flag
)
361 /* If tcsetpgrp failed in terminal_inferior, this would give us
362 our process group instead of the inferior's. See
363 terminal_inferior for details. */
364 tinfo
->process_group
= tcgetpgrp (0);
367 /* Set tty state to our_ttystate. */
368 serial_set_tty_state (stdin_serial
, our_terminal_info
.ttystate
);
372 #ifdef HAVE_TERMIOS_H
373 result
= tcsetpgrp (0, our_terminal_info
.process_group
);
375 /* This fails on Ultrix with EINVAL if you run the testsuite
376 in the background with nohup, and then log out. GDB never
377 used to check for an error here, so perhaps there are other
378 such situations as well. */
380 fprintf_unfiltered (gdb_stderr
,
381 "[tcsetpgrp failed in child_terminal_ours: %s]\n",
382 safe_strerror (errno
));
389 signal (SIGTTOU
, osigttou
);
394 signal (SIGINT
, sigint_ours
);
396 signal (SIGQUIT
, sigquit_ours
);
401 tinfo
->tflags
= fcntl (0, F_GETFL
, 0);
402 result
= fcntl (0, F_SETFL
, our_terminal_info
.tflags
);
407 /* Per-inferior data key. */
408 static const struct inferior_data
*inflow_inferior_data
;
411 inflow_inferior_data_cleanup (struct inferior
*inf
, void *arg
)
413 struct terminal_info
*info
= (struct terminal_info
*) arg
;
415 xfree (info
->run_terminal
);
416 xfree (info
->ttystate
);
420 /* Get the current svr4 data. If none is found yet, add it now. This
421 function always returns a valid object. */
423 static struct terminal_info
*
424 get_inflow_inferior_data (struct inferior
*inf
)
426 struct terminal_info
*info
;
428 info
= (struct terminal_info
*) inferior_data (inf
, inflow_inferior_data
);
431 info
= XCNEW (struct terminal_info
);
432 set_inferior_data (inf
, inflow_inferior_data
, info
);
438 /* This is a "inferior_exit" observer. Releases the TERMINAL_INFO member
439 of the inferior structure. This field is private to inflow.c, and
440 its type is opaque to the rest of GDB. PID is the target pid of
441 the inferior that is about to be removed from the inferior
445 inflow_inferior_exit (struct inferior
*inf
)
447 struct terminal_info
*info
;
449 info
= (struct terminal_info
*) inferior_data (inf
, inflow_inferior_data
);
452 xfree (info
->run_terminal
);
453 xfree (info
->ttystate
);
455 set_inferior_data (inf
, inflow_inferior_data
, NULL
);
460 copy_terminal_info (struct inferior
*to
, struct inferior
*from
)
462 struct terminal_info
*tinfo_to
, *tinfo_from
;
464 tinfo_to
= get_inflow_inferior_data (to
);
465 tinfo_from
= get_inflow_inferior_data (from
);
467 xfree (tinfo_to
->run_terminal
);
468 xfree (tinfo_to
->ttystate
);
470 *tinfo_to
= *tinfo_from
;
472 if (tinfo_from
->run_terminal
)
473 tinfo_to
->run_terminal
474 = xstrdup (tinfo_from
->run_terminal
);
476 if (tinfo_from
->ttystate
)
478 = serial_copy_tty_state (stdin_serial
, tinfo_from
->ttystate
);
482 info_terminal_command (char *arg
, int from_tty
)
484 target_terminal::info (arg
, from_tty
);
488 child_terminal_info (struct target_ops
*self
, const char *args
, int from_tty
)
490 struct inferior
*inf
;
491 struct terminal_info
*tinfo
;
493 if (!gdb_has_a_terminal ())
495 printf_filtered (_("This GDB does not control a terminal.\n"));
499 if (ptid_equal (inferior_ptid
, null_ptid
))
502 inf
= current_inferior ();
503 tinfo
= get_inflow_inferior_data (inf
);
505 printf_filtered (_("Inferior's terminal status "
506 "(currently saved by GDB):\n"));
508 /* First the fcntl flags. */
512 flags
= tinfo
->tflags
;
514 printf_filtered ("File descriptor flags = ");
517 #define O_ACCMODE (O_RDONLY | O_WRONLY | O_RDWR)
519 /* (O_ACCMODE) parens are to avoid Ultrix header file bug. */
520 switch (flags
& (O_ACCMODE
))
523 printf_filtered ("O_RDONLY");
526 printf_filtered ("O_WRONLY");
529 printf_filtered ("O_RDWR");
532 flags
&= ~(O_ACCMODE
);
535 if (flags
& O_NONBLOCK
)
536 printf_filtered (" | O_NONBLOCK");
537 flags
&= ~O_NONBLOCK
;
540 #if defined (O_NDELAY)
541 /* If O_NDELAY and O_NONBLOCK are defined to the same thing, we will
542 print it as O_NONBLOCK, which is good cause that is what POSIX
543 has, and the flag will already be cleared by the time we get here. */
544 if (flags
& O_NDELAY
)
545 printf_filtered (" | O_NDELAY");
549 if (flags
& O_APPEND
)
550 printf_filtered (" | O_APPEND");
553 #if defined (O_BINARY)
554 if (flags
& O_BINARY
)
555 printf_filtered (" | O_BINARY");
560 printf_filtered (" | 0x%x", flags
);
561 printf_filtered ("\n");
564 #ifdef HAVE_TERMIOS_H
565 printf_filtered ("Process group = %d\n", (int) tinfo
->process_group
);
568 serial_print_tty_state (stdin_serial
, tinfo
->ttystate
, gdb_stdout
);
571 /* NEW_TTY_PREFORK is called before forking a new child process,
572 so we can record the state of ttys in the child to be formed.
573 TTYNAME is null if we are to share the terminal with gdb;
574 or points to a string containing the name of the desired tty.
576 NEW_TTY is called in new child processes under Unix, which will
577 become debugger target processes. This actually switches to
578 the terminal specified in the NEW_TTY_PREFORK call. */
581 new_tty_prefork (const char *ttyname
)
583 /* Save the name for later, for determining whether we and the child
584 are sharing a tty. */
585 inferior_thisrun_terminal
= ttyname
;
588 #if !defined(__GO32__) && !defined(_WIN32)
589 /* If RESULT, assumed to be the return value from a system call, is
590 negative, print the error message indicated by errno and exit.
591 MSG should identify the operation that failed. */
593 check_syscall (const char *msg
, int result
)
597 print_sys_errmsg (msg
, errno
);
608 if (inferior_thisrun_terminal
== 0)
610 #if !defined(__GO32__) && !defined(_WIN32)
612 /* Disconnect the child process from our controlling terminal. On some
613 systems (SVR4 for example), this may cause a SIGTTOU, so temporarily
615 tty
= open ("/dev/tty", O_RDWR
);
618 sighandler_t osigttou
;
620 osigttou
= signal (SIGTTOU
, SIG_IGN
);
621 ioctl (tty
, TIOCNOTTY
, 0);
623 signal (SIGTTOU
, osigttou
);
627 /* Now open the specified new terminal. */
628 tty
= open (inferior_thisrun_terminal
, O_RDWR
| O_NOCTTY
);
629 check_syscall (inferior_thisrun_terminal
, tty
);
631 /* Avoid use of dup2; doesn't exist on all systems. */
635 check_syscall ("dup'ing tty into fd 0", dup (tty
));
640 check_syscall ("dup'ing tty into fd 1", dup (tty
));
645 check_syscall ("dup'ing tty into fd 2", dup (tty
));
649 /* Make tty our new controlling terminal. */
650 if (ioctl (tty
, TIOCSCTTY
, 0) == -1)
651 /* Mention GDB in warning because it will appear in the inferior's
652 terminal instead of GDB's. */
653 warning (_("GDB: Failed to set controlling terminal: %s"),
654 safe_strerror (errno
));
659 #endif /* !go32 && !win32 */
662 /* NEW_TTY_POSTFORK is called after forking a new child process, and
663 adding it to the inferior table, to store the TTYNAME being used by
664 the child, or null if it sharing the terminal with gdb. */
667 new_tty_postfork (void)
669 /* Save the name for later, for determining whether we and the child
670 are sharing a tty. */
672 if (inferior_thisrun_terminal
)
674 struct inferior
*inf
= current_inferior ();
675 struct terminal_info
*tinfo
= get_inflow_inferior_data (inf
);
677 tinfo
->run_terminal
= xstrdup (inferior_thisrun_terminal
);
680 inferior_thisrun_terminal
= NULL
;
684 /* Call set_sigint_trap when you need to pass a signal on to an attached
685 process when handling SIGINT. */
688 pass_signal (int signo
)
691 kill (ptid_get_pid (inferior_ptid
), SIGINT
);
695 static sighandler_t osig
;
699 set_sigint_trap (void)
701 struct inferior
*inf
= current_inferior ();
702 struct terminal_info
*tinfo
= get_inflow_inferior_data (inf
);
704 if (inf
->attach_flag
|| tinfo
->run_terminal
)
706 osig
= signal (SIGINT
, pass_signal
);
714 clear_sigint_trap (void)
718 signal (SIGINT
, osig
);
724 /* Create a new session if the inferior will run in a different tty.
725 A session is UNIX's way of grouping processes that share a controlling
726 terminal, so a new one is needed if the inferior terminal will be
727 different from GDB's.
729 Returns the session id of the new session, 0 if no session was created
730 or -1 if an error occurred. */
732 create_tty_session (void)
737 if (!job_control
|| inferior_thisrun_terminal
== 0)
742 warning (_("Failed to create new terminal session: setsid: %s"),
743 safe_strerror (errno
));
748 #endif /* HAVE_SETSID */
751 /* Get all the current tty settings (including whether we have a
752 tty at all!). We can't do this in _initialize_inflow because
753 serial_fdopen() won't work until the serial_ops_list is
754 initialized, but we don't want to do it lazily either, so
755 that we can guarantee stdin_serial is opened if there is
758 initialize_stdin_serial (void)
760 stdin_serial
= serial_fdopen (0);
764 _initialize_inflow (void)
766 add_info ("terminal", info_terminal_command
,
767 _("Print inferior's saved terminal status."));
769 terminal_is_ours
= 1;
771 /* OK, figure out whether we have job control. */
774 observer_attach_inferior_exit (inflow_inferior_exit
);
777 = register_inferior_data_with_cleanup (NULL
, inflow_inferior_data_cleanup
);