int uv_tty_init(uv_loop_t* loop, uv_tty_t* tty, int fd, int readable) {
int flags;
int newfd;
int r;
flags = 0;
newfd = -1;
uv__stream_init(loop, (uv_stream_t*) tty, UV_TTY);
/* Reopen the file descriptor when it refers to a tty. This lets us put the
* tty in non-blocking mode without affecting other processes that share it
* with us.
*
* Example: `node | cat` - if we put our fd 0 in non-blocking mode, it also
* affects fd 1 of `cat` because both file descriptors refer to the same
* struct file in the kernel. When we reopen our fd 0, it points to a
* different struct file, hence changing its properties doesn't affect
* other processes.
*/
if (isatty(fd)) {
r = uv__open_cloexec("/dev/tty", O_RDWR);
if (r < 0) {
/* fallback to using blocking writes */
if (!readable)
flags |= UV_STREAM_BLOCKING;
goto skip;
}
newfd = r;
r = uv__dup2_cloexec(newfd, fd);
if (r < 0 && r != -EINVAL) {
/* EINVAL means newfd == fd which could conceivably happen if another
* thread called close(fd) between our calls to isatty() and open().
* That's a rather unlikely event but let's handle it anyway.
*/
uv__close(newfd);
return r;
}
fd = newfd;
}
skip:
#if defined(__APPLE__)
r = uv__stream_try_select((uv_stream_t*) tty, &fd);
if (r) {
if (newfd != -1)
uv__close(newfd);
return r;
}
#endif
if (readable)
flags |= UV_STREAM_READABLE;
else
flags |= UV_STREAM_WRITABLE;
if (!(flags & UV_STREAM_BLOCKING))
uv__nonblock(fd, 1);
uv__stream_open((uv_stream_t*) tty, fd, flags);
tty->mode = UV_TTY_MODE_NORMAL;
return 0;
}
int uv_tty_init(uv_loop_t* loop, uv_tty_t* tty, int fd, int readable) {
uv_handle_type type;
int flags;
int newfd;
int r;
int saved_flags;
char path[256];
/* File descriptors that refer to files cannot be monitored with epoll.
* That restriction also applies to character devices like /dev/random
* (but obviously not /dev/tty.)
*/
type = uv_guess_handle(fd);
if (type == UV_FILE || type == UV_UNKNOWN_HANDLE)
return UV_EINVAL;
flags = 0;
newfd = -1;
/* Reopen the file descriptor when it refers to a tty. This lets us put the
* tty in non-blocking mode without affecting other processes that share it
* with us.
*
* Example: `node | cat` - if we put our fd 0 in non-blocking mode, it also
* affects fd 1 of `cat` because both file descriptors refer to the same
* struct file in the kernel. When we reopen our fd 0, it points to a
* different struct file, hence changing its properties doesn't affect
* other processes.
*/
if (type == UV_TTY) {
/* Reopening a pty in master mode won't work either because the reopened
* pty will be in slave mode (*BSD) or reopening will allocate a new
* master/slave pair (Linux). Therefore check if the fd points to a
* slave device.
*/
if (uv__tty_is_slave(fd) && ttyname_r(fd, path, sizeof(path)) == 0)
r = uv__open_cloexec(path, O_RDWR);
else
r = -1;
if (r < 0) {
/* fallback to using blocking writes */
if (!readable)
flags |= UV_HANDLE_BLOCKING_WRITES;
goto skip;
}
newfd = r;
r = uv__dup2_cloexec(newfd, fd);
if (r < 0 && r != UV_EINVAL) {
/* EINVAL means newfd == fd which could conceivably happen if another
* thread called close(fd) between our calls to isatty() and open().
* That's a rather unlikely event but let's handle it anyway.
*/
uv__close(newfd);
return r;
}
fd = newfd;
}
#if defined(__APPLE__)
/* Save the fd flags in case we need to restore them due to an error. */
do
saved_flags = fcntl(fd, F_GETFL);
while (saved_flags == -1 && errno == EINTR);
if (saved_flags == -1) {
if (newfd != -1)
uv__close(newfd);
return UV__ERR(errno);
}
#endif
/* Pacify the compiler. */
(void) &saved_flags;
skip:
uv__stream_init(loop, (uv_stream_t*) tty, UV_TTY);
/* If anything fails beyond this point we need to remove the handle from
* the handle queue, since it was added by uv__handle_init in uv_stream_init.
*/
if (!(flags & UV_HANDLE_BLOCKING_WRITES))
uv__nonblock(fd, 1);
#if defined(__APPLE__)
r = uv__stream_try_select((uv_stream_t*) tty, &fd);
if (r) {
int rc = r;
if (newfd != -1)
uv__close(newfd);
QUEUE_REMOVE(&tty->handle_queue);
do
r = fcntl(fd, F_SETFL, saved_flags);
while (r == -1 && errno == EINTR);
return rc;
}
#endif
if (readable)
flags |= UV_HANDLE_READABLE;
else
flags |= UV_HANDLE_WRITABLE;
uv__stream_open((uv_stream_t*) tty, fd, flags);
tty->mode = UV_TTY_MODE_NORMAL;
return 0;
}
