1/* Fork a Unix child process, and set up to debug it, for GDBserver.
2   Copyright (C) 1989-2020 Free Software Foundation, Inc.
3
4   This file is part of GDB.
5
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.
10
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.
15
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/>.  */
18
19#include "server.h"
20#include "gdbsupport/job-control.h"
21#include "nat/fork-inferior.h"
22#ifdef HAVE_SIGNAL_H
23#include <signal.h>
24#endif
25
26#ifdef SIGTTOU
27/* A file descriptor for the controlling terminal.  */
28static int terminal_fd;
29
30/* TERMINAL_FD's original foreground group.  */
31static pid_t old_foreground_pgrp;
32
33/* Hand back terminal ownership to the original foreground group.  */
34
35static void
36restore_old_foreground_pgrp (void)
37{
38  tcsetpgrp (terminal_fd, old_foreground_pgrp);
39}
40#endif
41
42/* See nat/fork-inferior.h.  */
43
44void
45prefork_hook (const char *args)
46{
47  client_state &cs = get_client_state ();
48  if (debug_threads)
49    {
50      debug_printf ("args: %s\n", args);
51      debug_flush ();
52    }
53
54#ifdef SIGTTOU
55  signal (SIGTTOU, SIG_DFL);
56  signal (SIGTTIN, SIG_DFL);
57#endif
58
59  /* Clear this so the backend doesn't get confused, thinking
60     CONT_THREAD died, and it needs to resume all threads.  */
61  cs.cont_thread = null_ptid;
62}
63
64/* See nat/fork-inferior.h.  */
65
66void
67postfork_hook (pid_t pid)
68{
69}
70
71/* See nat/fork-inferior.h.  */
72
73void
74postfork_child_hook ()
75{
76  /* This is set to the result of setpgrp, which if vforked, will be
77     visible to you in the parent process.  It's only used by humans
78     for debugging.  */
79  static int debug_setpgrp = 657473;
80
81  debug_setpgrp = gdb_setpgid ();
82  if (debug_setpgrp == -1)
83    perror (_("setpgrp failed in child"));
84}
85
86/* See nat/fork-inferior.h.  */
87
88void
89gdb_flush_out_err ()
90{
91  fflush (stdout);
92  fflush (stderr);
93}
94
95/* See server.h.  */
96
97void
98post_fork_inferior (int pid, const char *program)
99{
100  client_state &cs = get_client_state ();
101#ifdef SIGTTOU
102  signal (SIGTTOU, SIG_IGN);
103  signal (SIGTTIN, SIG_IGN);
104  terminal_fd = fileno (stderr);
105  old_foreground_pgrp = tcgetpgrp (terminal_fd);
106  tcsetpgrp (terminal_fd, pid);
107  atexit (restore_old_foreground_pgrp);
108#endif
109
110  startup_inferior (the_target, pid,
111		    START_INFERIOR_TRAPS_EXPECTED,
112		    &cs.last_status, &cs.last_ptid);
113  current_thread->last_resume_kind = resume_stop;
114  current_thread->last_status = cs.last_status;
115  signal_pid = pid;
116  target_post_create_inferior ();
117  fprintf (stderr, "Process %s created; pid = %d\n", program, pid);
118  fflush (stderr);
119}
120