binutils-gdb/gdb/inflow.c

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/* Low level interface to ptrace, for GDB when running under Unix.
Copyright (C) 1986-2018 Free Software Foundation, Inc.
This file is part of GDB.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
#include "defs.h"
#include "frame.h"
#include "inferior.h"
#include "command.h"
#include "serial.h"
#include "terminal.h"
#include "target.h"
#include "gdbthread.h"
#include "observer.h"
#include <signal.h>
#include <fcntl.h>
#include "gdb_select.h"
#include "inflow.h"
#include "gdbcmd.h"
#ifdef HAVE_TERMIOS_H
#include <termios.h>
#endif
#include "job-control.h"
#ifdef HAVE_SYS_IOCTL_H
#include <sys/ioctl.h>
#endif
#ifndef O_NOCTTY
#define O_NOCTTY 0
#endif
static void pass_signal (int);
static void child_terminal_ours_1 (target_terminal_state);
/* Record terminal status separately for debugger and inferior. */
static struct serial *stdin_serial;
/* Terminal related info we need to keep track of. Each inferior
holds an instance of this structure --- we save it whenever the
corresponding inferior stops, and restore it to the terminal when
the inferior is resumed in the foreground. */
struct terminal_info
{
/* The name of the tty (from the `tty' command) that we gave to the
inferior when it was started. */
char *run_terminal;
/* TTY state. We save it whenever the inferior stops, and restore
it when it resumes in the foreground. */
serial_ttystate ttystate;
#ifdef HAVE_TERMIOS_H
/* The terminal's foreground process group. Saved whenever the
inferior stops. This is the pgrp displayed by "info terminal".
Note that this may be not the inferior's actual process group,
since each inferior that we spawn has its own process group, and
only one can be in the foreground at a time. When the inferior
resumes, if we can determine the inferior's actual pgrp, then we
make that the foreground pgrp instead of what was saved here.
While it's a bit arbitrary which inferior's pgrp ends up in the
foreground when we resume several inferiors, this at least makes
'resume inf1+inf2' + 'stop all' + 'resume inf2' end up with
inf2's pgrp in the foreground instead of inf1's (which would be
problematic since it would be left stopped: Ctrl-C wouldn't work,
for example). */
pid_t process_group;
#endif
/* fcntl flags. Saved and restored just like ttystate. */
int tflags;
};
/* Our own tty state, which we restore every time we need to deal with
the terminal. This is set once, when GDB first starts, and then
whenever we enter/leave TUI mode (gdb_save_tty_state). The
settings of flags which readline saves and restores are
unimportant. */
static struct terminal_info our_terminal_info;
/* Snapshot of the initial tty state taken during initialization of
GDB, before readline/ncurses have had a chance to change it. This
is used as the initial tty state given to each new spawned
inferior. Unlike our_terminal_info, this is only ever set
once. */
static serial_ttystate initial_gdb_ttystate;
static struct terminal_info *get_inflow_inferior_data (struct inferior *);
/* RAII class used to ignore SIGTTOU in a scope. */
class scoped_ignore_sigttou
{
public:
scoped_ignore_sigttou ()
{
#ifdef SIGTTOU
if (job_control)
m_osigttou = signal (SIGTTOU, SIG_IGN);
#endif
}
~scoped_ignore_sigttou ()
{
#ifdef SIGTTOU
if (job_control)
signal (SIGTTOU, m_osigttou);
#endif
}
DISABLE_COPY_AND_ASSIGN (scoped_ignore_sigttou);
private:
#ifdef SIGTTOU
sighandler_t m_osigttou = NULL;
#endif
};
/* While the inferior is running, we want SIGINT and SIGQUIT to go to the
inferior only. If we have job control, that takes care of it. If not,
we save our handlers in these two variables and set SIGINT and SIGQUIT
to SIG_IGN. */
static sighandler_t sigint_ours;
static sighandler_t sigquit_ours;
/* The name of the tty (from the `tty' command) that we're giving to
the inferior when starting it up. This is only (and should only
be) used as a transient global by new_tty_prefork,
create_tty_session, new_tty and new_tty_postfork, all called from
fork_inferior, while forking a new child. */
static const char *inferior_thisrun_terminal;
/* Track who owns GDB's terminal (is it GDB or some inferior?). While
target_terminal::is_ours() etc. tracks the core's intention and is
independent of the target backend, this tracks the actual state of
GDB's own tty. So for example,
(target_terminal::is_inferior () && gdb_tty_state == terminal_is_ours)
is true when the (native) inferior is not sharing a terminal with
GDB (e.g., because we attached to an inferior that is running on a
different terminal). */
static target_terminal_state gdb_tty_state = target_terminal_state::is_ours;
/* See terminal.h. */
void
set_initial_gdb_ttystate (void)
{
/* Note we can't do any of this in _initialize_inflow because at
that point stdin_serial has not been created yet. */
initial_gdb_ttystate = serial_get_tty_state (stdin_serial);
if (initial_gdb_ttystate != NULL)
{
our_terminal_info.ttystate
= serial_copy_tty_state (stdin_serial, initial_gdb_ttystate);
#ifdef F_GETFL
our_terminal_info.tflags = fcntl (0, F_GETFL, 0);
#endif
#ifdef HAVE_TERMIOS_H
our_terminal_info.process_group = tcgetpgrp (0);
#endif
}
}
/* Does GDB have a terminal (on stdin)? */
static int
gdb_has_a_terminal (void)
{
return initial_gdb_ttystate != NULL;
}
/* Macro for printing errors from ioctl operations */
#define OOPSY(what) \
if (result == -1) \
fprintf_unfiltered(gdb_stderr, "[%s failed in terminal_inferior: %s]\n", \
what, safe_strerror (errno))
/* Initialize the terminal settings we record for the inferior,
before we actually run the inferior. */
void
child_terminal_init (struct target_ops *self)
{
if (!gdb_has_a_terminal ())
return;
inferior *inf = current_inferior ();
terminal_info *tinfo = get_inflow_inferior_data (inf);
#ifdef HAVE_TERMIOS_H
/* A child we spawn should be a process group leader (PGID==PID) at
this point, though that may not be true if we're attaching to an
existing process. */
tinfo->process_group = inf->pid;
#endif
xfree (tinfo->ttystate);
tinfo->ttystate = serial_copy_tty_state (stdin_serial, initial_gdb_ttystate);
}
/* Save the terminal settings again. This is necessary for the TUI
when it switches to TUI or non-TUI mode; curses changes the terminal
and gdb must be able to restore it correctly. */
void
gdb_save_tty_state (void)
{
if (gdb_has_a_terminal ())
{
xfree (our_terminal_info.ttystate);
our_terminal_info.ttystate = serial_get_tty_state (stdin_serial);
}
}
/* Try to determine whether TTY is GDB's input terminal. Returns
TRIBOOL_UNKNOWN if we can't tell. */
static tribool
is_gdb_terminal (const char *tty)
{
struct stat gdb_tty;
struct stat other_tty;
int res;
res = stat (tty, &other_tty);
if (res == -1)
return TRIBOOL_UNKNOWN;
res = fstat (STDIN_FILENO, &gdb_tty);
if (res == -1)
return TRIBOOL_UNKNOWN;
return ((gdb_tty.st_dev == other_tty.st_dev
&& gdb_tty.st_ino == other_tty.st_ino)
? TRIBOOL_TRUE
: TRIBOOL_FALSE);
}
/* Helper for sharing_input_terminal. Try to determine whether
inferior INF is using the same TTY for input as GDB is. Returns
TRIBOOL_UNKNOWN if we can't tell. */
static tribool
sharing_input_terminal_1 (inferior *inf)
{
/* Using host-dependent code here is fine, because the
child_terminal_foo functions are meant to be used by child/native
targets. */
#if defined (__linux__) || defined (__sun__)
char buf[100];
xsnprintf (buf, sizeof (buf), "/proc/%d/fd/0", inf->pid);
return is_gdb_terminal (buf);
#else
return TRIBOOL_UNKNOWN;
#endif
}
/* Return true if the inferior is using the same TTY for input as GDB
is. If this is true, then we save/restore terminal flags/state.
This is necessary because if inf->attach_flag is set, we don't
offhand know whether we are sharing a terminal with the inferior or
not. Attaching a process without a terminal is one case where we
do not; attaching a process which we ran from the same shell as GDB
via `&' is one case where we do.
If we can't determine, we assume the TTY is being shared. This
works OK if you're only debugging one inferior. However, if you're
debugging more than one inferior, and e.g., one is spawned by GDB
with "run" (sharing terminal with GDB), and another is attached to
(and running on a different terminal, as is most common), then it
matters, because we can only restore the terminal settings of one
of the inferiors, and in that scenario, we want to restore the
settings of the "run"'ed inferior.
Note, this is not the same as determining whether GDB and the
inferior are in the same session / connected to the same
controlling tty. An inferior (fork child) may call setsid,
disconnecting itself from the ctty, while still leaving
stdin/stdout/stderr associated with the original terminal. If
we're debugging that process, we should also save/restore terminal
settings. */
static bool
sharing_input_terminal (inferior *inf)
{
terminal_info *tinfo = get_inflow_inferior_data (inf);
tribool res = sharing_input_terminal_1 (inf);
if (res == TRIBOOL_UNKNOWN)
{
/* As fallback, if we can't determine by stat'ing the inferior's
tty directly (because it's not supported on this host) and
the child was spawned, check whether run_terminal is our tty.
This isn't ideal, since this is checking the child's
controlling terminal, not the input terminal (which may have
been redirected), but is still better than nothing. A false
positive ("set inferior-tty" points to our terminal, but I/O
was redirected) is much more likely than a false negative
("set inferior-tty" points to some other terminal, and then
output was redirected to our terminal), and with a false
positive we just end up trying to save/restore terminal
settings when we didn't need to or we actually can't. */
if (tinfo->run_terminal != NULL)
res = is_gdb_terminal (tinfo->run_terminal);
/* If we still can't determine, assume yes. */
if (res == TRIBOOL_UNKNOWN)
return true;
}
return res == TRIBOOL_TRUE;
}
/* Put the inferior's terminal settings into effect. This is
preparation for starting or resuming the inferior. */
void
child_terminal_inferior (struct target_ops *self)
{
/* If we resume more than one inferior in the foreground on GDB's
terminal, then the first inferior's terminal settings "win".
Note that every child process is put in its own process group, so
the first process that ends up resumed ends up determining which
process group the kernel forwards Ctrl-C/Ctrl-Z (SIGINT/SIGTTOU)
to. */
if (gdb_tty_state == target_terminal_state::is_inferior)
return;
inferior *inf = current_inferior ();
terminal_info *tinfo = get_inflow_inferior_data (inf);
if (gdb_has_a_terminal ()
&& tinfo->ttystate != NULL
&& sharing_input_terminal (inf))
{
int result;
/* Ignore SIGTTOU since it will happen when we try to set the
terminal's state (if gdb_tty_state is currently
ours_for_output). */
scoped_ignore_sigttou ignore_sigttou;
#ifdef F_GETFL
result = fcntl (0, F_SETFL, tinfo->tflags);
OOPSY ("fcntl F_SETFL");
#endif
result = serial_set_tty_state (stdin_serial, tinfo->ttystate);
OOPSY ("setting tty state");
if (!job_control)
{
sigint_ours = signal (SIGINT, SIG_IGN);
#ifdef SIGQUIT
sigquit_ours = signal (SIGQUIT, SIG_IGN);
#endif
}
if (job_control)
{
#ifdef HAVE_TERMIOS_H
/* If we can't tell the inferior's actual process group,
then restore whatever was the foreground pgrp the last
time the inferior was running. See also comments
describing terminal_state::process_group. */
#ifdef HAVE_GETPGID
result = tcsetpgrp (0, getpgid (inf->pid));
#else
result = tcsetpgrp (0, tinfo->process_group);
#endif
if (result == -1)
{
#if 0
/* This fails if either GDB has no controlling terminal,
e.g., running under 'setsid(1)', or if the inferior
is not attached to GDB's controlling terminal. E.g.,
if it called setsid to create a new session or used
the TIOCNOTTY ioctl, or simply if we've attached to a
process running on another terminal and we couldn't
tell whether it was sharing GDB's terminal (and so
assumed yes). */
fprintf_unfiltered
(gdb_stderr,
"[tcsetpgrp failed in child_terminal_inferior: %s]\n",
safe_strerror (errno));
#endif
}
#endif
}
gdb_tty_state = target_terminal_state::is_inferior;
}
}
/* Put some of our terminal settings into effect,
enough to get proper results from our output,
but do not change into or out of RAW mode
so that no input is discarded.
After doing this, either terminal_ours or terminal_inferior
should be called to get back to a normal state of affairs.
N.B. The implementation is (currently) no different than
child_terminal_ours. See child_terminal_ours_1. */
void
child_terminal_ours_for_output (struct target_ops *self)
{
child_terminal_ours_1 (target_terminal_state::is_ours_for_output);
}
/* Put our terminal settings into effect.
First record the inferior's terminal settings
so they can be restored properly later.
N.B. Targets that want to use this with async support must build that
support on top of this (e.g., the caller still needs to add stdin to the
event loop). E.g., see linux_nat_terminal_ours. */
void
child_terminal_ours (struct target_ops *self)
{
child_terminal_ours_1 (target_terminal_state::is_ours);
}
/* Save the current terminal settings in the inferior's terminal_info
cache. */
void
child_terminal_save_inferior (struct target_ops *self)
{
/* Avoid attempting all the ioctl's when running in batch. */
if (!gdb_has_a_terminal ())
return;
inferior *inf = current_inferior ();
terminal_info *tinfo = get_inflow_inferior_data (inf);
/* No need to save/restore if the inferior is not sharing GDB's
tty. */
if (!sharing_input_terminal (inf))
return;
xfree (tinfo->ttystate);
tinfo->ttystate = serial_get_tty_state (stdin_serial);
tinfo->process_group = tcgetpgrp (0);
#ifdef F_GETFL
tinfo->tflags = fcntl (0, F_GETFL, 0);
#endif
}
/* Switch terminal state to DESIRED_STATE, either is_ours, or
is_ours_for_output. */
static void
child_terminal_ours_1 (target_terminal_state desired_state)
{
gdb_assert (desired_state != target_terminal_state::is_inferior);
/* Avoid attempting all the ioctl's when running in batch. */
if (!gdb_has_a_terminal ())
return;
if (gdb_tty_state != desired_state)
{
int result ATTRIBUTE_UNUSED;
/* Ignore SIGTTOU since it will happen when we try to set the
terminal's pgrp. */
scoped_ignore_sigttou ignore_sigttou;
/* Set tty state to our_ttystate. */
serial_set_tty_state (stdin_serial, our_terminal_info.ttystate);
/* If we only want output, then leave the inferior's pgrp in the
foreground, so that Ctrl-C/Ctrl-Z reach the inferior
directly. */
if (job_control && desired_state == target_terminal_state::is_ours)
{
#ifdef HAVE_TERMIOS_H
result = tcsetpgrp (0, our_terminal_info.process_group);
#if 0
/* This fails on Ultrix with EINVAL if you run the testsuite
in the background with nohup, and then log out. GDB never
used to check for an error here, so perhaps there are other
such situations as well. */
if (result == -1)
fprintf_unfiltered (gdb_stderr,
"[tcsetpgrp failed in child_terminal_ours: %s]\n",
safe_strerror (errno));
#endif
#endif /* termios */
}
if (!job_control && desired_state == target_terminal_state::is_ours)
{
signal (SIGINT, sigint_ours);
#ifdef SIGQUIT
signal (SIGQUIT, sigquit_ours);
#endif
}
#ifdef F_GETFL
result = fcntl (0, F_SETFL, our_terminal_info.tflags);
#endif
gdb_tty_state = desired_state;
}
}
/* Interrupt the inferior. Implementation of target_interrupt for
child/native targets. */
void
child_interrupt (struct target_ops *self)
{
/* Interrupt the first inferior that has a resumed thread. */
thread_info *thr;
thread_info *resumed = NULL;
ALL_NON_EXITED_THREADS (thr)
{
if (thr->executing)
{
resumed = thr;
break;
}
if (thr->suspend.waitstatus_pending_p)
resumed = thr;
}
if (resumed != NULL)
{
/* Note that unlike pressing Ctrl-C on the controlling terminal,
here we only interrupt one process, not the whole process
group. This is because interrupting a process group (with
either Ctrl-C or with kill(3) with negative PID) sends a
SIGINT to each process in the process group, and we may not
be debugging all processes in the process group. */
kill (resumed->inf->pid, SIGINT);
}
}
/* Pass a Ctrl-C to the inferior as-if a Ctrl-C was pressed while the
inferior was in the foreground. Implementation of
target_pass_ctrlc for child/native targets. */
void
child_pass_ctrlc (struct target_ops *self)
{
gdb_assert (!target_terminal::is_ours ());
#ifdef HAVE_TERMIOS_H
if (job_control)
{
pid_t term_pgrp = tcgetpgrp (0);
/* If there's any inferior sharing our terminal, pass the SIGINT
to the terminal's foreground process group. This acts just
like the user typed a ^C on the terminal while the inferior
was in the foreground. Note that using a negative process
number in kill() is a System V-ism. The proper BSD interface
is killpg(). However, all modern BSDs support the System V
interface too. */
if (term_pgrp != -1 && term_pgrp != our_terminal_info.process_group)
{
kill (-term_pgrp, SIGINT);
return;
}
}
#endif
/* Otherwise, pass the Ctrl-C to the first inferior that was resumed
in the foreground. */
inferior *inf;
ALL_INFERIORS (inf)
{
if (inf->terminal_state != target_terminal_state::is_ours)
{
gdb_assert (inf->pid != 0);
kill (inf->pid, SIGINT);
return;
}
}
/* If no inferior was resumed in the foreground, then how did the
!is_ours assert above pass? */
gdb_assert_not_reached ("no inferior resumed in the fg found");
}
/* Per-inferior data key. */
static const struct inferior_data *inflow_inferior_data;
static void
inflow_inferior_data_cleanup (struct inferior *inf, void *arg)
{
struct terminal_info *info = (struct terminal_info *) arg;
xfree (info->run_terminal);
xfree (info->ttystate);
xfree (info);
}
/* Get the current svr4 data. If none is found yet, add it now. This
function always returns a valid object. */
static struct terminal_info *
get_inflow_inferior_data (struct inferior *inf)
{
struct terminal_info *info;
info = (struct terminal_info *) inferior_data (inf, inflow_inferior_data);
if (info == NULL)
{
info = XCNEW (struct terminal_info);
set_inferior_data (inf, inflow_inferior_data, info);
}
return info;
}
/* This is a "inferior_exit" observer. Releases the TERMINAL_INFO member
of the inferior structure. This field is private to inflow.c, and
its type is opaque to the rest of GDB. PID is the target pid of
the inferior that is about to be removed from the inferior
list. */
static void
inflow_inferior_exit (struct inferior *inf)
{
struct terminal_info *info;
inf->terminal_state = target_terminal_state::is_ours;
info = (struct terminal_info *) inferior_data (inf, inflow_inferior_data);
if (info != NULL)
{
xfree (info->run_terminal);
xfree (info->ttystate);
xfree (info);
set_inferior_data (inf, inflow_inferior_data, NULL);
}
}
void
copy_terminal_info (struct inferior *to, struct inferior *from)
{
struct terminal_info *tinfo_to, *tinfo_from;
tinfo_to = get_inflow_inferior_data (to);
tinfo_from = get_inflow_inferior_data (from);
xfree (tinfo_to->run_terminal);
xfree (tinfo_to->ttystate);
*tinfo_to = *tinfo_from;
if (tinfo_from->run_terminal)
tinfo_to->run_terminal
= xstrdup (tinfo_from->run_terminal);
if (tinfo_from->ttystate)
tinfo_to->ttystate
= serial_copy_tty_state (stdin_serial, tinfo_from->ttystate);
to->terminal_state = from->terminal_state;
}
void
info_terminal_command (const char *arg, int from_tty)
{
target_terminal::info (arg, from_tty);
}
void
child_terminal_info (struct target_ops *self, const char *args, int from_tty)
{
struct inferior *inf;
struct terminal_info *tinfo;
if (!gdb_has_a_terminal ())
{
printf_filtered (_("This GDB does not control a terminal.\n"));
return;
}
if (ptid_equal (inferior_ptid, null_ptid))
return;
inf = current_inferior ();
tinfo = get_inflow_inferior_data (inf);
printf_filtered (_("Inferior's terminal status "
"(currently saved by GDB):\n"));
/* First the fcntl flags. */
{
int flags;
flags = tinfo->tflags;
printf_filtered ("File descriptor flags = ");
#ifndef O_ACCMODE
#define O_ACCMODE (O_RDONLY | O_WRONLY | O_RDWR)
#endif
/* (O_ACCMODE) parens are to avoid Ultrix header file bug. */
switch (flags & (O_ACCMODE))
{
case O_RDONLY:
printf_filtered ("O_RDONLY");
break;
case O_WRONLY:
printf_filtered ("O_WRONLY");
break;
case O_RDWR:
printf_filtered ("O_RDWR");
break;
}
flags &= ~(O_ACCMODE);
#ifdef O_NONBLOCK
if (flags & O_NONBLOCK)
printf_filtered (" | O_NONBLOCK");
flags &= ~O_NONBLOCK;
#endif
#if defined (O_NDELAY)
/* If O_NDELAY and O_NONBLOCK are defined to the same thing, we will
print it as O_NONBLOCK, which is good cause that is what POSIX
has, and the flag will already be cleared by the time we get here. */
if (flags & O_NDELAY)
printf_filtered (" | O_NDELAY");
flags &= ~O_NDELAY;
#endif
if (flags & O_APPEND)
printf_filtered (" | O_APPEND");
flags &= ~O_APPEND;
#if defined (O_BINARY)
if (flags & O_BINARY)
printf_filtered (" | O_BINARY");
flags &= ~O_BINARY;
#endif
if (flags)
printf_filtered (" | 0x%x", flags);
printf_filtered ("\n");
}
#ifdef HAVE_TERMIOS_H
printf_filtered ("Process group = %d\n", (int) tinfo->process_group);
#endif
serial_print_tty_state (stdin_serial, tinfo->ttystate, gdb_stdout);
}
/* NEW_TTY_PREFORK is called before forking a new child process,
so we can record the state of ttys in the child to be formed.
TTYNAME is null if we are to share the terminal with gdb;
or points to a string containing the name of the desired tty.
NEW_TTY is called in new child processes under Unix, which will
become debugger target processes. This actually switches to
the terminal specified in the NEW_TTY_PREFORK call. */
void
new_tty_prefork (const char *ttyname)
{
/* Save the name for later, for determining whether we and the child
are sharing a tty. */
inferior_thisrun_terminal = ttyname;
}
#if !defined(__GO32__) && !defined(_WIN32)
/* If RESULT, assumed to be the return value from a system call, is
negative, print the error message indicated by errno and exit.
MSG should identify the operation that failed. */
static void
check_syscall (const char *msg, int result)
{
if (result < 0)
{
print_sys_errmsg (msg, errno);
_exit (1);
}
}
#endif
void
new_tty (void)
{
int tty;
if (inferior_thisrun_terminal == 0)
return;
#if !defined(__GO32__) && !defined(_WIN32)
#ifdef TIOCNOTTY
/* Disconnect the child process from our controlling terminal. On some
systems (SVR4 for example), this may cause a SIGTTOU, so temporarily
ignore SIGTTOU. */
tty = open ("/dev/tty", O_RDWR);
if (tty > 0)
{
scoped_ignore_sigttou ignore_sigttou;
ioctl (tty, TIOCNOTTY, 0);
close (tty);
}
#endif
/* Now open the specified new terminal. */
tty = open (inferior_thisrun_terminal, O_RDWR | O_NOCTTY);
check_syscall (inferior_thisrun_terminal, tty);
/* Avoid use of dup2; doesn't exist on all systems. */
if (tty != 0)
{
close (0);
check_syscall ("dup'ing tty into fd 0", dup (tty));
}
if (tty != 1)
{
close (1);
check_syscall ("dup'ing tty into fd 1", dup (tty));
}
if (tty != 2)
{
close (2);
check_syscall ("dup'ing tty into fd 2", dup (tty));
}
#ifdef TIOCSCTTY
/* Make tty our new controlling terminal. */
if (ioctl (tty, TIOCSCTTY, 0) == -1)
/* Mention GDB in warning because it will appear in the inferior's
terminal instead of GDB's. */
warning (_("GDB: Failed to set controlling terminal: %s"),
safe_strerror (errno));
#endif
if (tty > 2)
close (tty);
#endif /* !go32 && !win32 */
}
/* NEW_TTY_POSTFORK is called after forking a new child process, and
adding it to the inferior table, to store the TTYNAME being used by
the child, or null if it sharing the terminal with gdb. */
void
new_tty_postfork (void)
{
/* Save the name for later, for determining whether we and the child
are sharing a tty. */
if (inferior_thisrun_terminal)
{
struct inferior *inf = current_inferior ();
struct terminal_info *tinfo = get_inflow_inferior_data (inf);
tinfo->run_terminal = xstrdup (inferior_thisrun_terminal);
}
inferior_thisrun_terminal = NULL;
}
/* Call set_sigint_trap when you need to pass a signal on to an attached
process when handling SIGINT. */
static void
pass_signal (int signo)
{
#ifndef _WIN32
kill (ptid_get_pid (inferior_ptid), SIGINT);
#endif
}
static sighandler_t osig;
static int osig_set;
void
set_sigint_trap (void)
{
struct inferior *inf = current_inferior ();
struct terminal_info *tinfo = get_inflow_inferior_data (inf);
if (inf->attach_flag || tinfo->run_terminal)
{
osig = signal (SIGINT, pass_signal);
osig_set = 1;
}
else
osig_set = 0;
}
void
clear_sigint_trap (void)
{
if (osig_set)
{
signal (SIGINT, osig);
osig_set = 0;
}
}
/* Create a new session if the inferior will run in a different tty.
A session is UNIX's way of grouping processes that share a controlling
terminal, so a new one is needed if the inferior terminal will be
different from GDB's.
Returns the session id of the new session, 0 if no session was created
or -1 if an error occurred. */
pid_t
create_tty_session (void)
{
#ifdef HAVE_SETSID
pid_t ret;
if (!job_control || inferior_thisrun_terminal == 0)
return 0;
ret = setsid ();
if (ret == -1)
warning (_("Failed to create new terminal session: setsid: %s"),
safe_strerror (errno));
return ret;
#else
return 0;
#endif /* HAVE_SETSID */
}
/* Get all the current tty settings (including whether we have a
tty at all!). We can't do this in _initialize_inflow because
serial_fdopen() won't work until the serial_ops_list is
initialized, but we don't want to do it lazily either, so
that we can guarantee stdin_serial is opened if there is
a terminal. */
void
initialize_stdin_serial (void)
{
stdin_serial = serial_fdopen (0);
}
void
_initialize_inflow (void)
{
add_info ("terminal", info_terminal_command,
_("Print inferior's saved terminal status."));
/* OK, figure out whether we have job control. */
have_job_control ();
observer_attach_inferior_exit (inflow_inferior_exit);
inflow_inferior_data
= register_inferior_data_with_cleanup (NULL, inflow_inferior_data_cleanup);
}