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. */
28 static int terminal_fd;
29
30 /* TERMINAL_FD's original foreground group. */
31 static pid_t old_foreground_pgrp;
32
33 /* Hand back terminal ownership to the original foreground group. */
34
35 static void
restore_old_foreground_pgrp(void)36 restore_old_foreground_pgrp (void)
37 {
38 tcsetpgrp (terminal_fd, old_foreground_pgrp);
39 }
40 #endif
41
42 /* See nat/fork-inferior.h. */
43
44 void
prefork_hook(const char * args)45 prefork_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
66 void
postfork_hook(pid_t pid)67 postfork_hook (pid_t pid)
68 {
69 }
70
71 /* See nat/fork-inferior.h. */
72
73 void
postfork_child_hook()74 postfork_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
88 void
gdb_flush_out_err()89 gdb_flush_out_err ()
90 {
91 fflush (stdout);
92 fflush (stderr);
93 }
94
95 /* See server.h. */
96
97 void
post_fork_inferior(int pid,const char * program)98 post_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