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/* Fork a Unix child process, and set up to debug it, for GDB.
Copyright (C) 1990-2021 Free Software Foundation, Inc.
Contributed by Cygnus Support.
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 "inferior.h"
#include "gdbcmd.h"
#include "terminal.h"
#include "gdbthread.h"
#include "top.h"
#include "gdbsupport/job-control.h"
#include "gdbsupport/filestuff.h"
#include "nat/fork-inferior.h"
#include "gdbsupport/common-inferior.h"
/* The exec-wrapper, if any, that will be used when starting the
inferior. */
static std::string exec_wrapper;
/* See gdbsupport/common-inferior.h. */
const char *
get_exec_wrapper ()
{
return !exec_wrapper.empty () ? exec_wrapper.c_str () : nullptr;
}
/* See nat/fork-inferior.h. */
void
gdb_flush_out_err ()
{
gdb_flush (main_ui->m_gdb_stdout);
gdb_flush (main_ui->m_gdb_stderr);
}
/* The ui structure that will be saved on 'prefork_hook' and
restored on 'postfork_hook'. */
static struct ui *saved_ui = NULL;
/* See nat/fork-inferior.h. */
void
prefork_hook (const char *args)
{
gdb_assert (saved_ui == NULL);
/* Retain a copy of our UI, since the child will replace this value
and if we're vforked, we have to restore it. */
saved_ui = current_ui;
/* Tell the terminal handling subsystem what tty we plan to run on;
it will just record the information for later. */
new_tty_prefork (current_inferior ()->tty ());
}
/* See nat/fork-inferior.h. */
void
postfork_hook (pid_t pid)
{
inferior *inf = current_inferior ();
inferior_appeared (inf, pid);
gdb_assert (saved_ui != NULL);
current_ui = saved_ui;
saved_ui = NULL;
new_tty_postfork ();
}
/* See nat/fork-inferior.h. */
void
postfork_child_hook ()
{
/* This is set to the result of setpgrp, which if vforked, will be
visible to you in the parent process. It's only used by humans
for debugging. */
static int debug_setpgrp = 657473;
/* Make sure we switch to main_ui here in order to be able to
use the fprintf_unfiltered/warning/error functions. */
current_ui = main_ui;
/* Create a new session for the inferior process, if necessary.
It will also place the inferior in a separate process group. */
if (create_tty_session () <= 0)
{
/* No session was created, but we still want to run the inferior
in a separate process group. */
debug_setpgrp = gdb_setpgid ();
if (debug_setpgrp == -1)
perror (_("setpgrp failed in child"));
}
/* Ask the tty subsystem to switch to the one we specified
earlier (or to share the current terminal, if none was
specified). */
new_tty ();
}
/* See inferior.h. */
ptid_t
gdb_startup_inferior (pid_t pid, int num_traps)
{
inferior *inf = current_inferior ();
process_stratum_target *proc_target = inf->process_target ();
ptid_t ptid = startup_inferior (proc_target, pid, num_traps, NULL, NULL);
/* Mark all threads non-executing. */
set_executing (proc_target, ptid, false);
return ptid;
}
/* Implement the "unset exec-wrapper" command. */
static void
unset_exec_wrapper_command (const char *args, int from_tty)
{
exec_wrapper.clear ();
}
static void
show_startup_with_shell (struct ui_file *file, int from_tty,
struct cmd_list_element *c, const char *value)
{
fprintf_filtered (file,
_("Use of shell to start subprocesses is %s.\n"),
value);
}
void _initialize_fork_child ();
void
_initialize_fork_child ()
{
add_setshow_filename_cmd ("exec-wrapper", class_run, &exec_wrapper, _("\
Set a wrapper for running programs.\n\
The wrapper prepares the system and environment for the new program."),
_("\
Show the wrapper for running programs."), NULL,
NULL, NULL,
&setlist, &showlist);
add_cmd ("exec-wrapper", class_run, unset_exec_wrapper_command,
_("Disable use of an execution wrapper."),
&unsetlist);
add_setshow_boolean_cmd ("startup-with-shell", class_support,
&startup_with_shell, _("\
Set use of shell to start subprocesses. The default is on."), _("\
Show use of shell to start subprocesses."), NULL,
NULL,
show_startup_with_shell,
&setlist, &showlist);
}
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