]>
Commit | Line | Data |
---|---|---|
dff8da6b | 1 | /* Copyright (C) 1997-2024 Free Software Foundation, Inc. |
af6f3906 UD |
2 | This file is part of the GNU C Library. |
3 | ||
4 | The GNU C Library is free software; you can redistribute it and/or | |
41bdb6e2 AJ |
5 | modify it under the terms of the GNU Lesser General Public |
6 | License as published by the Free Software Foundation; either | |
7 | version 2.1 of the License, or (at your option) any later version. | |
af6f3906 UD |
8 | |
9 | The GNU C Library 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 GNU | |
41bdb6e2 | 12 | Lesser General Public License for more details. |
af6f3906 | 13 | |
41bdb6e2 | 14 | You should have received a copy of the GNU Lesser General Public |
59ba27a6 | 15 | License along with the GNU C Library; if not, see |
5a82c748 | 16 | <https://www.gnu.org/licenses/>. */ |
af6f3906 UD |
17 | |
18 | #include <errno.h> | |
19 | #include <termios.h> | |
20 | #include <sys/ioctl.h> | |
21 | #include <sys/types.h> | |
22 | #include <unistd.h> | |
23 | ||
24 | /* Return the session ID of FD. */ | |
25 | pid_t | |
9d46370c | 26 | tcgetsid (int fd) |
af6f3906 UD |
27 | { |
28 | pid_t pgrp; | |
29 | pid_t sid; | |
30 | #ifdef TIOCGSID | |
344c67b6 | 31 | static int tiocgsid_does_not_work; |
af6f3906 | 32 | |
344c67b6 | 33 | if (! tiocgsid_does_not_work) |
af6f3906 UD |
34 | { |
35 | int serrno = errno; | |
36 | int sid; | |
37 | ||
38 | if (__ioctl (fd, TIOCGSID, &sid) < 0) | |
39 | { | |
40 | if (errno == EINVAL) | |
41 | { | |
344c67b6 | 42 | tiocgsid_does_not_work = 1; |
af6f3906 UD |
43 | __set_errno (serrno); |
44 | } | |
45 | else | |
46 | return (pid_t) -1; | |
47 | } | |
48 | else | |
49 | return (pid_t) sid; | |
50 | } | |
51 | #endif | |
52 | ||
53 | pgrp = tcgetpgrp (fd); | |
54 | if (pgrp == -1) | |
55 | return (pid_t) -1; | |
56 | ||
57 | sid = getsid (pgrp); | |
58 | if (sid == -1 && errno == ESRCH) | |
59 | __set_errno (ENOTTY); | |
60 | ||
61 | return sid; | |
62 | } |