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c4563d2d | 1 | /* Copyright (C) 1997, 1999 Free Software Foundation, Inc. |
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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 | |
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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. | |
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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 | |
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14 | You should have received a copy of the GNU Lesser General Public |
15 | License along with the GNU C Library; if not, write to the Free | |
16 | Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA | |
17 | 02111-1307 USA. */ | |
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18 | |
19 | #include <errno.h> | |
20 | #include <termios.h> | |
21 | #include <sys/ioctl.h> | |
22 | #include <sys/types.h> | |
23 | #include <unistd.h> | |
24 | ||
25 | /* Return the session ID of FD. */ | |
26 | pid_t | |
27 | tcgetsid (fd) | |
28 | int fd; | |
29 | { | |
30 | pid_t pgrp; | |
31 | pid_t sid; | |
32 | #ifdef TIOCGSID | |
344c67b6 | 33 | static int tiocgsid_does_not_work; |
af6f3906 | 34 | |
344c67b6 | 35 | if (! tiocgsid_does_not_work) |
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36 | { |
37 | int serrno = errno; | |
38 | int sid; | |
39 | ||
40 | if (__ioctl (fd, TIOCGSID, &sid) < 0) | |
41 | { | |
42 | if (errno == EINVAL) | |
43 | { | |
344c67b6 | 44 | tiocgsid_does_not_work = 1; |
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45 | __set_errno (serrno); |
46 | } | |
47 | else | |
48 | return (pid_t) -1; | |
49 | } | |
50 | else | |
51 | return (pid_t) sid; | |
52 | } | |
53 | #endif | |
54 | ||
55 | pgrp = tcgetpgrp (fd); | |
56 | if (pgrp == -1) | |
57 | return (pid_t) -1; | |
58 | ||
59 | sid = getsid (pgrp); | |
60 | if (sid == -1 && errno == ESRCH) | |
61 | __set_errno (ENOTTY); | |
62 | ||
63 | return sid; | |
64 | } |