release/src/router/rp-l2tp/handlers/pty.c

   1 /***********************************************************************
   2 *
   3 * pty.c
   4 *
   5 * Code for dealing with pseudo-tty's for running pppd.
   6 *
   7 * Copyright (C) 2002 Roaring Penguin Software Inc.
   8 *
   9 * This software may be distributed under the terms of the GNU General
  10 * Public License, Version 2, or (at your option) any later version.
  11 *
  12 * LIC: GPL
  13 *
  14 ***********************************************************************/
  15
  16 static char const RCSID[] =
  17 "$Id: pty.c,v 1.1.48.1 2005/08/08 12:05:25 honor Exp $";
  18
  19 #include "../l2tp.h"
  20 #include <sys/ioctl.h>
  21 #include <termios.h>
  22 #include <fcntl.h>
  23 #include <stdio.h>
  24 #ifndef N_HDLC
  25 #include <linux/termios.h>
  26 #endif
  27
  28 /**********************************************************************
  29 * %FUNCTION: pty_get
  30 * %ARGUMENTS:
  31 *  mfp -- pointer to master file descriptor
  32 *  sfp -- pointer to slave file descriptor
  33 * %RETURNS:
  34 *  0 on success, -1 on failure
  35 * %DESCRIPTION:
  36 *  Opens a PTY and sets line discipline to N_HDLC for ppp.
  37 *  Taken almost verbatim from Linux pppd code.
  38 ***********************************************************************/
  39 int
  40 pty_get(int *mfp, int *sfp)
  41 {
  42     char pty_name[24];
  43     struct termios tios;
  44     int mfd, sfd;
  45     int disc = N_HDLC;
  46
  47     mfd = -1;
  48     sfd = -1;
  49
  50     mfd = open("/dev/ptmx", O_RDWR);
  51     if (mfd >= 0) {
  52         int ptn;
  53         if (ioctl(mfd, TIOCGPTN, &ptn) >= 0) {
  54             snprintf(pty_name, sizeof(pty_name), "/dev/pts/%d", ptn);
  55             ptn = 0;
  56             if (ioctl(mfd, TIOCSPTLCK, &ptn) < 0) {
  57                 /* warn("Couldn't unlock pty slave %s: %m", pty_name); */
  58             }
  59             if ((sfd = open(pty_name, O_RDWR | O_NOCTTY)) < 0) {
  60                 /* warn("Couldn't open pty slave %s: %m", pty_name); */
  61             }
  62         }
  63     }
  64
  65     if (sfd < 0 || mfd < 0) {
  66         if (sfd >= 0) close(sfd);
  67         if (mfd >= 0) close(mfd);
  68         return -1;
  69     }
  70
  71     *mfp = mfd;
  72     *sfp = sfd;
  73     if (tcgetattr(sfd, &tios) == 0) {
  74         tios.c_cflag &= ~(CSIZE | CSTOPB | PARENB);
  75         tios.c_cflag |= CS8 | CREAD | CLOCAL;
  76         tios.c_iflag  = IGNPAR;
  77         tios.c_oflag  = 0;
  78         tios.c_lflag  = 0;
  79         tcsetattr(sfd, TCSAFLUSH, &tios);
  80     }
  81     if (ioctl(sfd, TIOCSETD, &disc) < 0) {
  82         l2tp_set_errmsg("Unable to set line discipline to N_HDLC");
  83         close(mfd);
  84         close(sfd);
  85         return -1;
  86     }
  87     disc = N_HDLC;
  88     if (ioctl(mfd, TIOCSETD, &disc) < 0) {
  89         l2tp_set_errmsg("Unable to set line discipline to N_HDLC");
  90         close(mfd);
  91         close(sfd);
  92         return -1;
  93     }
  94     return 0;
  95 }
  96