1 /* Determine the session ID of the controlling terminal of the current process. 2 Copyright (C) 2010-2021 Free Software Foundation, Inc. 3 4 This file is free software: you can redistribute it and/or modify 5 it under the terms of the GNU Lesser General Public License as 6 published by the Free Software Foundation; either version 3 of the 7 License, or (at your option) any later version. 8 9 This file is distributed in the hope that it will be useful, 10 but WITHOUT ANY WARRANTY; without even the implied warranty of 11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12 GNU Lesser General Public License for more details. 13 14 You should have received a copy of the GNU Lesser General Public License 15 along with this program. If not, see <https://www.gnu.org/licenses/>. */ 16 17 #include <config.h> 18 19 #define USE_OLD_TTY /* needed on OpenBSD 4.5, so that TIOCGSID gets defined */ 20 21 /* Specification. */ 22 #include <termios.h> 23 24 #include <errno.h> 25 #include <sys/ioctl.h> 26 27 pid_t 28 tcgetsid (int fd) /* */ 29 { 30 #ifdef TIOCGSID /* Mac OS X, OpenBSD */ 31 int sid; 32 33 if (ioctl (fd, TIOCGSID, &sid) < 0) 34 return -1; /* errno is set here */ 35 36 return sid; 37 #else /* FreeBSD, Cygwin, mingw */ 38 errno = ENOSYS; 39 return -1; 40 #endif 41 }