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 #include "private/FdPath.h" 41 42 int getpt() { 43 return posix_openpt(O_RDWR|O_NOCTTY); 44 } 45 46 int grantpt(int) { 47 return 0; 48 } 49 50 int posix_openpt(int flags) { 51 return open("/dev/ptmx", flags); 52 } 53 54 char* ptsname(int fd) { 55 bionic_tls& tls = __get_bionic_tls(); 56 char* buf = tls.ptsname_buf; 57 int error = ptsname_r(fd, buf, sizeof(tls.ptsname_buf)); 58 return (error == 0) ? buf : NULL; 59 } 60 61 int ptsname_r(int fd, char* buf, size_t len) { 62 if (buf == NULL) { 63 errno = EINVAL; 64 return errno; 65 } 66 67 unsigned int pty_num; 68 if (ioctl(fd, TIOCGPTN, &pty_num) != 0) { 69 errno = ENOTTY; 70 return errno; 71 } 72 73 if (snprintf(buf, len, "/dev/pts/%u", pty_num) >= static_cast<int>(len)) { 74 errno = ERANGE; 75 return errno; 76 } 77 78 return 0; 79 } 80 81 char* ttyname(int fd) { 82 bionic_tls& tls = __get_bionic_tls(); 83 char* buf = tls.ttyname_buf; 84 int error = ttyname_r(fd, buf, sizeof(tls.ttyname_buf)); 85 return (error == 0) ? buf : NULL; 86 } 87 88 int ttyname_r(int fd, char* buf, size_t len) { 89 if (buf == NULL) { 90 errno = EINVAL; 91 return errno; 92 } 93 94 if (!isatty(fd)) { 95 return errno; 96 } 97 98 ssize_t count = readlink(FdPath(fd).c_str(), buf, len); 99 if (count == -1) { 100 return errno; 101 } 102 if (static_cast<size_t>(count) == len) { 103 errno = ERANGE; 104 return errno; 105 } 106 buf[count] = '\0'; 107 return 0; 108 } 109 110 int unlockpt(int fd) { 111 int unlock = 0; 112 return ioctl(fd, TIOCSPTLCK, &unlock); 113 } 114 115 int openpty(int* master, int* slave, char* name, const termios* t, const winsize* ws) { 116 *master = getpt(); 117 if (*master == -1) { 118 return -1; 119 } 120 121 if (grantpt(*master) == -1 || unlockpt(*master) == -1) { 122 close(*master); 123 return -1; 124 } 125 126 char buf[32]; 127 if (name == NULL) { 128 name = buf; 129 } 130 if (ptsname_r(*master, name, sizeof(buf)) != 0) { 131 close(*master); 132 return -1; 133 } 134 135 *slave = open(name, O_RDWR|O_NOCTTY); 136 if (*slave == -1) { 137 close(*master); 138 return -1; 139 } 140 141 if (t != NULL) { 142 tcsetattr(*slave, TCSAFLUSH, t); 143 } 144 if (ws != NULL) { 145 ioctl(*slave, TIOCSWINSZ, ws); 146 } 147 148 return 0; 149 } 150 151 int forkpty(int* amaster, char* name, const termios* t, const winsize* ws) { 152 int master; 153 int slave; 154 if (openpty(&master, &slave, name, t, ws) == -1) { 155 return -1; 156 } 157 158 pid_t pid = fork(); 159 if (pid == -1) { 160 close(master); 161 close(slave); 162 return -1; 163 } 164 165 if (pid == 0) { 166 // Child. 167 *amaster = -1; 168 close(master); 169 if (login_tty(slave) == -1) { 170 _exit(1); 171 } 172 return 0; 173 } 174 175 // Parent. 176 *amaster = master; 177 close(slave); 178 return pid; 179 } 180 181 int login_tty(int fd) { 182 setsid(); 183 184 if (ioctl(fd, TIOCSCTTY, NULL) == -1) { 185 return -1; 186 } 187 188 dup2(fd, STDIN_FILENO); 189 dup2(fd, STDOUT_FILENO); 190 dup2(fd, STDERR_FILENO); 191 if (fd > STDERR_FILENO) { 192 close(fd); 193 } 194 195 return 0; 196 } 197
