1 /* This testcase is part of GDB, the GNU debugger. 2 3 Copyright 2017-2020 Free Software Foundation, Inc. 4 5 This program is free software; you can redistribute it and/or modify 6 it under the terms of the GNU General Public License as published by 7 the Free Software Foundation; either version 3 of the License, or 8 (at your option) any later version. 9 10 This program is distributed in the hope that it will be useful, 11 but WITHOUT ANY WARRANTY; without even the implied warranty of 12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 GNU General Public License for more details. 14 15 You should have received a copy of the GNU General Public License 16 along with this program. If not, see <http://www.gnu.org/licenses/>. */ 17 18 #include <unistd.h> 19 #include <stdlib.h> 20 #include <assert.h> 21 22 static void 23 daemon_main (void) 24 { 25 } 26 27 int 28 main () 29 { 30 pid_t child; 31 32 alarm (60); 33 34 /* Normally we're a progress group leader at this point, so can't 35 create a session. Fork so the child can create a new 36 session. */ 37 child = fork (); 38 if (child == -1) 39 return 1; 40 else if (child != 0) 41 return 0; 42 else 43 { 44 /* In child. Switch to a new session. */ 45 pid_t session = setsid (); 46 if (session == -1) 47 return 1; 48 49 /* Fork again, so that the grand child (what we want to debug) 50 can't accidentally acquire a controlling terminal, because 51 it's not a session leader. We're not opening any file here, 52 but this is representative of what daemons do. */ 53 child = fork (); 54 if (child == -1) 55 return 1; 56 else if (child != 0) 57 return 0; 58 59 /* In grandchild. */ 60 daemon_main (); 61 62 while (1) 63 sleep (1); 64 } 65 66 return 0; 67 } 68