1 /* Copyright (C) 1998, 1999, 2000, 2001, 2002 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3 Contributed by Zack Weinberg <zack@rabi.phys.columbia.edu>, 1998.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library 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 GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <http://www.gnu.org/licenses/>. */
18
19 #include <errno.h>
20 #include <fcntl.h>
21 #include <string.h>
22 #include <unistd.h>
23
24 #if defined __USE_BSD
25
26 /* Prefix for master pseudo terminal nodes. */
27 #define _PATH_PTY "/dev/pty"
28
29 /* Letters indicating a series of pseudo terminals. */
30 #ifndef PTYNAME1
31 #define PTYNAME1 "pqrsPQRS"
32 #endif
33 const char __libc_ptyname1[] attribute_hidden = PTYNAME1;
34
35 /* Letters indicating the position within a series. */
36 #ifndef PTYNAME2
37 #define PTYNAME2 "0123456789abcdefghijklmnopqrstuv";
38 #endif
39 const char __libc_ptyname2[] attribute_hidden = PTYNAME2;
40
41 /* Open a master pseudo terminal and return its file descriptor. */
42 static __inline__ int
__getpt(void)43 __getpt (void)
44 {
45 char buf[sizeof (_PATH_PTY) + 2];
46 const char *p, *q;
47 char *s;
48
49 s = mempcpy (buf, _PATH_PTY, sizeof (_PATH_PTY) - 1);
50 /* s[0] and s[1] will be filled in the loop. */
51 s[2] = '\0';
52
53 for (p = __libc_ptyname1; *p != '\0'; ++p)
54 {
55 s[0] = *p;
56
57 for (q = __libc_ptyname2; *q != '\0'; ++q)
58 {
59 int fd;
60
61 s[1] = *q;
62
63 fd = open (buf, O_RDWR);
64 if (fd != -1)
65 return fd;
66
67 if (errno == ENOENT)
68 return -1;
69 }
70 }
71
72 __set_errno (ENOENT);
73 return -1;
74 }
75 #endif /* __USE_BSD */
76