1/* Fork a Unix child process, and set up to debug it, for GDBserver. 2 Copyright (C) 1989-2023 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 "gdbsupport/scoped_restore.h" 22#include "nat/fork-inferior.h" 23#ifdef HAVE_SIGNAL_H 24#include <signal.h> 25#endif 26 27#ifdef SIGTTOU 28/* A file descriptor for the controlling terminal. */ 29static int terminal_fd; 30 31/* TERMINAL_FD's original foreground group. */ 32static pid_t old_foreground_pgrp; 33 34/* Hand back terminal ownership to the original foreground group. */ 35 36static void 37restore_old_foreground_pgrp (void) 38{ 39 tcsetpgrp (terminal_fd, old_foreground_pgrp); 40} 41#endif 42 43/* See nat/fork-inferior.h. */ 44 45void 46prefork_hook (const char *args) 47{ 48 client_state &cs = get_client_state (); 49 threads_debug_printf ("args: %s", args); 50 51#ifdef SIGTTOU 52 signal (SIGTTOU, SIG_DFL); 53 signal (SIGTTIN, SIG_DFL); 54#endif 55 56 /* Clear this so the backend doesn't get confused, thinking 57 CONT_THREAD died, and it needs to resume all threads. */ 58 cs.cont_thread = null_ptid; 59} 60 61/* See nat/fork-inferior.h. */ 62 63void 64postfork_hook (pid_t pid) 65{ 66} 67 68/* See nat/fork-inferior.h. */ 69 70void 71postfork_child_hook () 72{ 73 /* This is set to the result of setpgrp, which if vforked, will be 74 visible to you in the parent process. It's only used by humans 75 for debugging. */ 76 static int debug_setpgrp = 657473; 77 78 debug_setpgrp = gdb_setpgid (); 79 if (debug_setpgrp == -1) 80 perror (_("setpgrp failed in child")); 81} 82 83/* See nat/fork-inferior.h. */ 84 85void 86gdb_flush_out_err () 87{ 88 fflush (stdout); 89 fflush (stderr); 90} 91 92/* See server.h. */ 93 94void 95post_fork_inferior (int pid, const char *program) 96{ 97 client_state &cs = get_client_state (); 98#ifdef SIGTTOU 99 signal (SIGTTOU, SIG_IGN); 100 signal (SIGTTIN, SIG_IGN); 101 terminal_fd = fileno (stderr); 102 old_foreground_pgrp = tcgetpgrp (terminal_fd); 103 tcsetpgrp (terminal_fd, pid); 104 atexit (restore_old_foreground_pgrp); 105#endif 106 107 process_info *proc = find_process_pid (pid); 108 109 /* If the inferior fails to start, startup_inferior mourns the 110 process (which deletes it), and then throws an error. This means 111 that on exception return, we don't need or want to clear this 112 flag back, as PROC won't exist anymore. Thus, we don't use a 113 scoped_restore. */ 114 proc->starting_up = true; 115 116 startup_inferior (the_target, pid, 117 START_INFERIOR_TRAPS_EXPECTED, 118 &cs.last_status, &cs.last_ptid); 119 120 /* If we get here, the process was successfully started. */ 121 proc->starting_up = false; 122 123 current_thread->last_resume_kind = resume_stop; 124 current_thread->last_status = cs.last_status; 125 signal_pid = pid; 126 target_post_create_inferior (); 127 fprintf (stderr, "Process %s created; pid = %d\n", program, pid); 128 fflush (stderr); 129} 130