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 "private/ThreadLocalBuffer.h" 40 41 static ThreadLocalBuffer<char, 32> g_ptsname_tls_buffer; 42 static ThreadLocalBuffer<char, 64> g_ttyname_tls_buffer; 43 44 int getpt() { 45 return posix_openpt(O_RDWR|O_NOCTTY); 46 } 47 48 int grantpt(int) { 49 return 0; 50 } 51 52 int posix_openpt(int flags) { 53 return open("/dev/ptmx", flags); 54 } 55 56 char* ptsname(int fd) { 57 char* buf = g_ptsname_tls_buffer.get(); 58 int error = ptsname_r(fd, buf, g_ptsname_tls_buffer.size()); 59 return (error == 0) ? buf : NULL; 60 } 61 62 int ptsname_r(int fd, char* buf, size_t len) { 63 if (buf == NULL) { 64 errno = EINVAL; 65 return errno; 66 } 67 68 unsigned int pty_num; 69 if (ioctl(fd, TIOCGPTN, &pty_num) != 0) { 70 errno = ENOTTY; 71 return errno; 72 } 73 74 if (snprintf(buf, len, "/dev/pts/%u", pty_num) >= static_cast<int>(len)) { 75 errno = ERANGE; 76 return errno; 77 } 78 79 return 0; 80 } 81 82 char* ttyname(int fd) { 83 char* buf = g_ttyname_tls_buffer.get(); 84 int error = ttyname_r(fd, buf, g_ttyname_tls_buffer.size()); 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 char path[64]; 99 snprintf(path, sizeof(path), "/proc/self/fd/%d", fd); 100 101 ssize_t count = readlink(path, buf, len); 102 if (count == -1) { 103 return errno; 104 } 105 if (static_cast<size_t>(count) == len) { 106 errno = ERANGE; 107 return errno; 108 } 109 buf[count] = '\0'; 110 return 0; 111 } 112 113 int unlockpt(int fd) { 114 int unlock = 0; 115 return ioctl(fd, TIOCSPTLCK, &unlock); 116 } 117 118 int openpty(int* master, int* slave, char* name, const termios* t, const winsize* ws) { 119 *master = getpt(); 120 if (*master == -1) { 121 return -1; 122 } 123 124 if (grantpt(*master) == -1 || unlockpt(*master) == -1) { 125 close(*master); 126 return -1; 127 } 128 129 char buf[32]; 130 if (name == NULL) { 131 name = buf; 132 } 133 if (ptsname_r(*master, name, sizeof(buf)) != 0) { 134 close(*master); 135 return -1; 136 } 137 138 *slave = open(name, O_RDWR|O_NOCTTY); 139 if (*slave == -1) { 140 close(*master); 141 return -1; 142 } 143 144 if (t != NULL) { 145 tcsetattr(*slave, TCSAFLUSH, t); 146 } 147 if (ws != NULL) { 148 ioctl(*slave, TIOCSWINSZ, ws); 149 } 150 151 return 0; 152 } 153 154 int forkpty(int* amaster, char* name, const termios* t, const winsize* ws) { 155 int master; 156 int slave; 157 if (openpty(&master, &slave, name, t, ws) == -1) { 158 return -1; 159 } 160 161 pid_t pid = fork(); 162 if (pid == -1) { 163 close(master); 164 close(slave); 165 return -1; 166 } 167 168 if (pid == 0) { 169 // Child. 170 *amaster = -1; 171 close(master); 172 if (login_tty(slave) == -1) { 173 _exit(1); 174 } 175 return 0; 176 } 177 178 // Parent. 179 *amaster = master; 180 close(slave); 181 return pid; 182 } 183 184 int login_tty(int fd) { 185 setsid(); 186 187 if (ioctl(fd, TIOCSCTTY, NULL) == -1) { 188 return -1; 189 } 190 191 dup2(fd, STDIN_FILENO); 192 dup2(fd, STDOUT_FILENO); 193 dup2(fd, STDERR_FILENO); 194 if (fd > STDERR_FILENO) { 195 close(fd); 196 } 197 198 return 0; 199 } 200
