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/*
* Copyright (C) 2008 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <errno.h>
#include <fcntl.h>
#include <pty.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/ioctl.h>
#include <termios.h>
#include <unistd.h>
#include <utmp.h>
#include "private/ThreadLocalBuffer.h"
static ThreadLocalBuffer<char, 32> g_ptsname_tls_buffer;
static ThreadLocalBuffer<char, 64> g_ttyname_tls_buffer;
int getpt() {
return posix_openpt(O_RDWR|O_NOCTTY);
}
int grantpt(int) {
return 0;
}
int posix_openpt(int flags) {
return open("/dev/ptmx", flags);
}
char* ptsname(int fd) {
char* buf = g_ptsname_tls_buffer.get();
int error = ptsname_r(fd, buf, g_ptsname_tls_buffer.size());
return (error == 0) ? buf : NULL;
}
int ptsname_r(int fd, char* buf, size_t len) {
if (buf == NULL) {
errno = EINVAL;
return errno;
}
unsigned int pty_num;
if (ioctl(fd, TIOCGPTN, &pty_num) != 0) {
errno = ENOTTY;
return errno;
}
if (snprintf(buf, len, "/dev/pts/%u", pty_num) >= static_cast<int>(len)) {
errno = ERANGE;
return errno;
}
return 0;
}
char* ttyname(int fd) {
char* buf = g_ttyname_tls_buffer.get();
int error = ttyname_r(fd, buf, g_ttyname_tls_buffer.size());
return (error == 0) ? buf : NULL;
}
int ttyname_r(int fd, char* buf, size_t len) {
if (buf == NULL) {
errno = EINVAL;
return errno;
}
if (!isatty(fd)) {
return errno;
}
char path[64];
snprintf(path, sizeof(path), "/proc/self/fd/%d", fd);
ssize_t count = readlink(path, buf, len);
if (count == -1) {
return errno;
}
if (static_cast<size_t>(count) == len) {
errno = ERANGE;
return errno;
}
buf[count] = '\0';
return 0;
}
int unlockpt(int fd) {
int unlock = 0;
return ioctl(fd, TIOCSPTLCK, &unlock);
}
int openpty(int* master, int* slave, char* name, const termios* t, const winsize* ws) {
*master = getpt();
if (*master == -1) {
return -1;
}
if (grantpt(*master) == -1 || unlockpt(*master) == -1) {
close(*master);
return -1;
}
char buf[32];
if (name == NULL) {
name = buf;
}
if (ptsname_r(*master, name, sizeof(buf)) != 0) {
close(*master);
return -1;
}
*slave = open(name, O_RDWR|O_NOCTTY);
if (*slave == -1) {
close(*master);
return -1;
}
if (t != NULL) {
tcsetattr(*slave, TCSAFLUSH, t);
}
if (ws != NULL) {
ioctl(*slave, TIOCSWINSZ, ws);
}
return 0;
}
int forkpty(int* master, char* name, const termios* t, const winsize* ws) {
int slave;
if (openpty(master, &slave, name, t, ws) == -1) {
return -1;
}
pid_t pid = fork();
if (pid == -1) {
close(*master);
close(slave);
return -1;
}
if (pid == 0) {
// Child.
close(*master);
if (login_tty(slave) == -1) {
_exit(1);
}
return 0;
}
// Parent.
close(slave);
return pid;
}
int login_tty(int fd) {
setsid();
if (ioctl(fd, TIOCSCTTY, NULL) == -1) {
return -1;
}
dup2(fd, STDIN_FILENO);
dup2(fd, STDOUT_FILENO);
dup2(fd, STDERR_FILENO);
if (fd > STDERR_FILENO) {
close(fd);
}
return 0;
}
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