1 /*
2 * Copyright (C) 2008 The Android Open Source Project
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * * Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * * Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in
12 * the documentation and/or other materials provided with the
13 * distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
18 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
19 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
22 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
25 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29 #include <errno.h>
30 #include <fcntl.h>
31 #include <pty.h>
32 #include <stdio.h>
33 #include <stdlib.h>
34 #include <sys/ioctl.h>
35 #include <termios.h>
36 #include <unistd.h>
37 #include <utmp.h>
38
39 #include "bionic/pthread_internal.h"
40
getpt()41 int getpt() {
42 return posix_openpt(O_RDWR|O_NOCTTY);
43 }
44
grantpt(int)45 int grantpt(int) {
46 return 0;
47 }
48
posix_openpt(int flags)49 int posix_openpt(int flags) {
50 return open("/dev/ptmx", flags);
51 }
52
ptsname(int fd)53 char* ptsname(int fd) {
54 bionic_tls& tls = __get_bionic_tls();
55 char* buf = tls.ptsname_buf;
56 int error = ptsname_r(fd, buf, sizeof(tls.ptsname_buf));
57 return (error == 0) ? buf : NULL;
58 }
59
ptsname_r(int fd,char * buf,size_t len)60 int ptsname_r(int fd, char* buf, size_t len) {
61 if (buf == NULL) {
62 errno = EINVAL;
63 return errno;
64 }
65
66 unsigned int pty_num;
67 if (ioctl(fd, TIOCGPTN, &pty_num) != 0) {
68 errno = ENOTTY;
69 return errno;
70 }
71
72 if (snprintf(buf, len, "/dev/pts/%u", pty_num) >= static_cast<int>(len)) {
73 errno = ERANGE;
74 return errno;
75 }
76
77 return 0;
78 }
79
ttyname(int fd)80 char* ttyname(int fd) {
81 bionic_tls& tls = __get_bionic_tls();
82 char* buf = tls.ttyname_buf;
83 int error = ttyname_r(fd, buf, sizeof(tls.ttyname_buf));
84 return (error == 0) ? buf : NULL;
85 }
86
ttyname_r(int fd,char * buf,size_t len)87 int ttyname_r(int fd, char* buf, size_t len) {
88 if (buf == NULL) {
89 errno = EINVAL;
90 return errno;
91 }
92
93 if (!isatty(fd)) {
94 return errno;
95 }
96
97 char path[64];
98 snprintf(path, sizeof(path), "/proc/self/fd/%d", fd);
99
100 ssize_t count = readlink(path, buf, len);
101 if (count == -1) {
102 return errno;
103 }
104 if (static_cast<size_t>(count) == len) {
105 errno = ERANGE;
106 return errno;
107 }
108 buf[count] = '\0';
109 return 0;
110 }
111
unlockpt(int fd)112 int unlockpt(int fd) {
113 int unlock = 0;
114 return ioctl(fd, TIOCSPTLCK, &unlock);
115 }
116
openpty(int * master,int * slave,char * name,const termios * t,const winsize * ws)117 int openpty(int* master, int* slave, char* name, const termios* t, const winsize* ws) {
118 *master = getpt();
119 if (*master == -1) {
120 return -1;
121 }
122
123 if (grantpt(*master) == -1 || unlockpt(*master) == -1) {
124 close(*master);
125 return -1;
126 }
127
128 char buf[32];
129 if (name == NULL) {
130 name = buf;
131 }
132 if (ptsname_r(*master, name, sizeof(buf)) != 0) {
133 close(*master);
134 return -1;
135 }
136
137 *slave = open(name, O_RDWR|O_NOCTTY);
138 if (*slave == -1) {
139 close(*master);
140 return -1;
141 }
142
143 if (t != NULL) {
144 tcsetattr(*slave, TCSAFLUSH, t);
145 }
146 if (ws != NULL) {
147 ioctl(*slave, TIOCSWINSZ, ws);
148 }
149
150 return 0;
151 }
152
forkpty(int * amaster,char * name,const termios * t,const winsize * ws)153 int forkpty(int* amaster, char* name, const termios* t, const winsize* ws) {
154 int master;
155 int slave;
156 if (openpty(&master, &slave, name, t, ws) == -1) {
157 return -1;
158 }
159
160 pid_t pid = fork();
161 if (pid == -1) {
162 close(master);
163 close(slave);
164 return -1;
165 }
166
167 if (pid == 0) {
168 // Child.
169 *amaster = -1;
170 close(master);
171 if (login_tty(slave) == -1) {
172 _exit(1);
173 }
174 return 0;
175 }
176
177 // Parent.
178 *amaster = master;
179 close(slave);
180 return pid;
181 }
182
login_tty(int fd)183 int login_tty(int fd) {
184 setsid();
185
186 if (ioctl(fd, TIOCSCTTY, NULL) == -1) {
187 return -1;
188 }
189
190 dup2(fd, STDIN_FILENO);
191 dup2(fd, STDOUT_FILENO);
192 dup2(fd, STDERR_FILENO);
193 if (fd > STDERR_FILENO) {
194 close(fd);
195 }
196
197 return 0;
198 }
199