glibc/login/openpty.c

140 lines
3.4 KiB
C

/* Copyright (C) 1998, 1999, 2004 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Zack Weinberg <zack@rabi.phys.columbia.edu>, 1998.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <pty.h>
#include <stdlib.h>
#include <string.h>
#include <termios.h>
#include <unistd.h>
#include <sys/types.h>
/* Return the result of ptsname_r in the buffer pointed to by PTS,
which should be of length BUF_LEN. If it is too long to fit in
this buffer, a sufficiently long buffer is allocated using malloc,
and returned in PTS. 0 is returned upon success, -1 otherwise. */
static int
pts_name (int fd, char **pts, size_t buf_len)
{
int rv;
char *buf = *pts;
for (;;)
{
char *new_buf;
if (buf_len)
{
rv = ptsname_r (fd, buf, buf_len);
if (rv != 0 || memchr (buf, '\0', buf_len))
/* We either got an error, or we succeeded and the
returned name fit in the buffer. */
break;
/* Try again with a longer buffer. */
buf_len += buf_len; /* Double it */
}
else
/* No initial buffer; start out by mallocing one. */
buf_len = 128; /* First time guess. */
if (buf != *pts)
/* We've already malloced another buffer at least once. */
new_buf = realloc (buf, buf_len);
else
new_buf = malloc (buf_len);
if (! new_buf)
{
rv = -1;
__set_errno (ENOMEM);
break;
}
buf = new_buf;
}
if (rv == 0)
*pts = buf; /* Return buffer to the user. */
else if (buf != *pts)
free (buf); /* Free what we malloced when returning an error. */
return rv;
}
/* Create pseudo tty master slave pair and set terminal attributes
according to TERMP and WINP. Return handles for both ends in
AMASTER and ASLAVE, and return the name of the slave end in NAME. */
int
openpty (int *amaster, int *aslave, char *name, struct termios *termp,
struct winsize *winp)
{
#ifdef PATH_MAX
char _buf[PATH_MAX];
#else
char _buf[512];
#endif
char *buf = _buf;
int master, slave;
master = getpt ();
if (master == -1)
return -1;
if (grantpt (master))
goto fail;
if (unlockpt (master))
goto fail;
if (pts_name (master, &buf, sizeof (_buf)))
goto fail;
slave = open (buf, O_RDWR | O_NOCTTY);
if (slave == -1)
{
if (buf != _buf)
free (buf);
goto fail;
}
/* XXX Should we ignore errors here? */
if(termp)
tcsetattr (slave, TCSAFLUSH, termp);
if (winp)
ioctl (slave, TIOCSWINSZ, winp);
*amaster = master;
*aslave = slave;
if (name != NULL)
strcpy (name, buf);
if (buf != _buf)
free (buf);
return 0;
fail:
close (master);
return -1;
}
libutil_hidden_def (openpty)