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04277e02 | 1 | /* Copyright (C) 1998-2019 Free Software Foundation, Inc. |
6591c335 UD |
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 | |
41bdb6e2 AJ |
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. | |
6591c335 UD |
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 | |
41bdb6e2 | 13 | Lesser General Public License for more details. |
6591c335 | 14 | |
41bdb6e2 | 15 | You should have received a copy of the GNU Lesser General Public |
59ba27a6 PE |
16 | License along with the GNU C Library; if not, see |
17 | <http://www.gnu.org/licenses/>. */ | |
6591c335 | 18 | |
00bc5db0 | 19 | #include <errno.h> |
6591c335 | 20 | #include <fcntl.h> |
00bc5db0 | 21 | #include <limits.h> |
6591c335 UD |
22 | #include <pty.h> |
23 | #include <stdlib.h> | |
24 | #include <string.h> | |
25 | #include <termios.h> | |
26 | #include <unistd.h> | |
27 | #include <sys/types.h> | |
28 | ||
6591c335 | 29 | |
00bc5db0 UD |
30 | /* Return the result of ptsname_r in the buffer pointed to by PTS, |
31 | which should be of length BUF_LEN. If it is too long to fit in | |
32 | this buffer, a sufficiently long buffer is allocated using malloc, | |
33 | and returned in PTS. 0 is returned upon success, -1 otherwise. */ | |
34 | static int | |
35 | pts_name (int fd, char **pts, size_t buf_len) | |
36 | { | |
37 | int rv; | |
38 | char *buf = *pts; | |
39 | ||
40 | for (;;) | |
41 | { | |
42 | char *new_buf; | |
43 | ||
44 | if (buf_len) | |
45 | { | |
46 | rv = ptsname_r (fd, buf, buf_len); | |
47 | ||
48 | if (rv != 0 || memchr (buf, '\0', buf_len)) | |
49 | /* We either got an error, or we succeeded and the | |
50 | returned name fit in the buffer. */ | |
51 | break; | |
52 | ||
53 | /* Try again with a longer buffer. */ | |
54 | buf_len += buf_len; /* Double it */ | |
55 | } | |
56 | else | |
57 | /* No initial buffer; start out by mallocing one. */ | |
58 | buf_len = 128; /* First time guess. */ | |
59 | ||
60 | if (buf != *pts) | |
61 | /* We've already malloced another buffer at least once. */ | |
62 | new_buf = realloc (buf, buf_len); | |
63 | else | |
64 | new_buf = malloc (buf_len); | |
65 | if (! new_buf) | |
66 | { | |
67 | rv = -1; | |
68 | __set_errno (ENOMEM); | |
69 | break; | |
70 | } | |
71 | buf = new_buf; | |
72 | } | |
73 | ||
74 | if (rv == 0) | |
75 | *pts = buf; /* Return buffer to the user. */ | |
76 | else if (buf != *pts) | |
77 | free (buf); /* Free what we malloced when returning an error. */ | |
78 | ||
79 | return rv; | |
80 | } | |
81 | ||
82 | /* Create pseudo tty master slave pair and set terminal attributes | |
83 | according to TERMP and WINP. Return handles for both ends in | |
84 | AMASTER and ASLAVE, and return the name of the slave end in NAME. */ | |
6591c335 | 85 | int |
4bcecfb7 RM |
86 | openpty (int *amaster, int *aslave, char *name, |
87 | const struct termios *termp, const struct winsize *winp) | |
6591c335 | 88 | { |
00bc5db0 UD |
89 | #ifdef PATH_MAX |
90 | char _buf[PATH_MAX]; | |
91 | #else | |
92 | char _buf[512]; | |
93 | #endif | |
94 | char *buf = _buf; | |
98e07420 | 95 | int master, ret = -1, slave = -1; |
6591c335 | 96 | |
645ac9aa CB |
97 | *buf = '\0'; |
98 | ||
00bc5db0 UD |
99 | master = getpt (); |
100 | if (master == -1) | |
6591c335 UD |
101 | return -1; |
102 | ||
00bc5db0 | 103 | if (grantpt (master)) |
98e07420 | 104 | goto on_error; |
00bc5db0 UD |
105 | |
106 | if (unlockpt (master)) | |
98e07420 | 107 | goto on_error; |
6591c335 | 108 | |
645ac9aa CB |
109 | #ifdef TIOCGPTPEER |
110 | /* Try to allocate slave fd solely based on master fd first. */ | |
111 | slave = ioctl (master, TIOCGPTPEER, O_RDWR | O_NOCTTY); | |
112 | #endif | |
00bc5db0 | 113 | if (slave == -1) |
645ac9aa CB |
114 | { |
115 | /* Fallback to path-based slave fd allocation in case kernel doesn't | |
116 | * support TIOCGPTPEER. | |
117 | */ | |
118 | if (pts_name (master, &buf, sizeof (_buf))) | |
119 | goto on_error; | |
120 | ||
121 | slave = open (buf, O_RDWR | O_NOCTTY); | |
122 | if (slave == -1) | |
123 | goto on_error; | |
124 | } | |
6591c335 UD |
125 | |
126 | /* XXX Should we ignore errors here? */ | |
b301e68e | 127 | if (termp) |
00bc5db0 | 128 | tcsetattr (slave, TCSAFLUSH, termp); |
b301e68e | 129 | #ifdef TIOCSWINSZ |
00bc5db0 UD |
130 | if (winp) |
131 | ioctl (slave, TIOCSWINSZ, winp); | |
b301e68e | 132 | #endif |
00bc5db0 UD |
133 | |
134 | *amaster = master; | |
135 | *aslave = slave; | |
136 | if (name != NULL) | |
645ac9aa CB |
137 | { |
138 | if (*buf == '\0') | |
139 | if (pts_name (master, &buf, sizeof (_buf))) | |
140 | goto on_error; | |
141 | ||
142 | strcpy (name, buf); | |
143 | } | |
6591c335 | 144 | |
98e07420 CB |
145 | ret = 0; |
146 | ||
147 | on_error: | |
148 | if (ret == -1) { | |
149 | close (master); | |
150 | ||
151 | if (slave != -1) | |
152 | close (slave); | |
153 | } | |
154 | ||
00bc5db0 UD |
155 | if (buf != _buf) |
156 | free (buf); | |
6d8ec2b1 | 157 | |
98e07420 | 158 | return ret; |
6591c335 | 159 | } |
e8210ece | 160 | libutil_hidden_def (openpty) |