text: /*-
   * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
   *
   * Copyright (c) 1999 Brian Somers <brian@Awfulhak.org>
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. 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 AUTHOR 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 AUTHOR 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.
   *
   * $FreeBSD$
   */
  
  #include <sys/param.h>
  #include <sys/un.h>
  #if defined(__OpenBSD__) || defined(__NetBSD__)
  #include <sys/ioctl.h>
  #endif
  
  #include <errno.h>
  #include <fcntl.h>
  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  #include <sysexits.h>
  #include <sys/uio.h>
  #include <termios.h>
  #include <ttyent.h>
  #include <unistd.h>
  #ifndef NONETGRAPH
  #include <netgraph.h>
  #include <netgraph/ng_async.h>
  #include <netgraph/ng_message.h>
  #include <netgraph/ng_ppp.h>
  #include <netgraph/ng_tty.h>
  #endif
  
  #include "layer.h"
  #include "defs.h"
  #include "mbuf.h"
  #include "log.h"
  #include "timer.h"
  #include "lqr.h"
  #include "hdlc.h"
  #include "throughput.h"
  #include "fsm.h"
  #include "lcp.h"
  #include "ccp.h"
  #include "link.h"
  #include "async.h"
  #include "descriptor.h"
  #include "physical.h"
  #include "mp.h"
  #include "chat.h"
  #include "auth.h"
  #include "chap.h"
  #include "cbcp.h"
  #include "datalink.h"
  #include "main.h"
  #include "id.h"
  #include "tty.h"
  
  #if defined(__mac68k__) || defined(__macppc__)
  #undef	CRTS_IFLOW
  #undef	CCTS_OFLOW
  #define	CRTS_IFLOW	CDTRCTS
  #define	CCTS_OFLOW	CDTRCTS
  #endif
  
  #define	Online(dev)	((dev)->mbits & TIOCM_CD)
  
  struct ttydevice {
    struct device dev;		/* What struct physical knows about */
    struct pppTimer Timer;	/* CD checks */
    int mbits;			/* Current DCD status */
    int carrier_seconds;		/* seconds before CD is *required* */
  #ifndef NONETGRAPH
    struct {
      unsigned speed;		/* Pre-line-discipline speed */
      int fd;			/* Pre-line-discipline fd */
      int disc;			/* Old line-discipline */
    } real;
    char hook[sizeof NG_ASYNC_HOOK_SYNC]; /* our ng_socket hook */
    int cs;			/* A netgraph control socket (maybe) */
  #endif
    struct termios ios;		/* To be able to reset from raw mode */
  };
  
  #define device2tty(d) ((d)->type == TTY_DEVICE ? (struct ttydevice *)d : NULL)
  
  unsigned
  tty_DeviceSize(void)
  {
    return sizeof(struct ttydevice);
  }
  
  /*
   * tty_Timeout() watches the DCD signal and mentions it if it's status
   * changes.
   */
  static void
  tty_Timeout(void *data)
  {
    struct physical *p = data;
    struct ttydevice *dev = device2tty(p->handler);
    int ombits, change;
  
    timer_Stop(&dev->Timer);
    dev->Timer.load = SECTICKS;		/* Once a second please */
    timer_Start(&dev->Timer);
    ombits = dev->mbits;
  
    if (p->fd >= 0) {
      if (ioctl(p->fd, TIOCMGET, &dev->mbits) < 0) {
        /* we must be a pty ? */
        if (p->cfg.cd.necessity != CD_DEFAULT)
          log_Printf(LogWARN, "%s: Carrier ioctl not supported, "
                     "using ``set cd off''\n", p->link.name);
        timer_Stop(&dev->Timer);
        dev->mbits = TIOCM_CD;
        return;
      }
    } else
      dev->mbits = 0;
  
    if (ombits == -1) {
      /* First time looking for carrier */
      if (Online(dev))
        log_Printf(LogPHASE, "%s: %s: CD detected\n", p->link.name, p->name.full);
      else if (++dev->carrier_seconds >= dev->dev.cd.delay) {
        if (dev->dev.cd.necessity == CD_REQUIRED)
          log_Printf(LogPHASE, "%s: %s: Required CD not detected\n",
                     p->link.name, p->name.full);
        else {
          log_Printf(LogPHASE, "%s: %s doesn't support CD\n",
                     p->link.name, p->name.full);
          dev->mbits = TIOCM_CD;		/* Dodgy null-modem cable ? */
        }
        timer_Stop(&dev->Timer);
        /* tty_AwaitCarrier() will notice */
      } else {
        /* Keep waiting */
        log_Printf(LogDEBUG, "%s: %s: Still no carrier (%d/%d)\n",
                   p->link.name, p->name.full, dev->carrier_seconds,
                   dev->dev.cd.delay);
        dev->mbits = -1;
      }
    } else {
      change = ombits ^ dev->mbits;
      if (change & TIOCM_CD) {
        if (dev->mbits & TIOCM_CD)
          log_Printf(LogDEBUG, "%s: offline -> online\n", p->link.name);
        else {
          log_Printf(LogDEBUG, "%s: online -> offline\n", p->link.name);
          log_Printf(LogPHASE, "%s: Carrier lost\n", p->link.name);
          datalink_Down(p->dl, CLOSE_NORMAL);
          timer_Stop(&dev->Timer);
        }
      } else
        log_Printf(LogDEBUG, "%s: Still %sline\n", p->link.name,
                   Online(dev) ? "on" : "off");
    }
  }
  
  static void
  tty_StartTimer(struct physical *p)
  {
    struct ttydevice *dev = device2tty(p->handler);
  
    timer_Stop(&dev->Timer);
    dev->Timer.load = SECTICKS;
    dev->Timer.func = tty_Timeout;
    dev->Timer.name = "tty CD";
    dev->Timer.arg = p;
    log_Printf(LogDEBUG, "%s: Using tty_Timeout [%p]\n",
               p->link.name, tty_Timeout);
    timer_Start(&dev->Timer);
  }
  
  static int
  tty_AwaitCarrier(struct physical *p)
  {
    struct ttydevice *dev = device2tty(p->handler);
  
    if (dev->dev.cd.necessity == CD_NOTREQUIRED || physical_IsSync(p))
      return CARRIER_OK;
  
    if (dev->mbits == -1) {
      if (dev->Timer.state == TIMER_STOPPED) {
        dev->carrier_seconds = 0;
        tty_StartTimer(p);
      }
      return CARRIER_PENDING;			/* Not yet ! */
    }
  
    return Online(dev) ? CARRIER_OK : CARRIER_LOST;
  }
  
  #ifdef NONETGRAPH
  #define tty_SetAsyncParams	NULL
  #define tty_Write		NULL
  #define tty_Read		NULL
  #else
  
  static int
  isngtty(struct ttydevice *dev)
  {
    return dev->real.fd != -1;
  }
  
  static void
  tty_SetAsyncParams(struct physical *p, u_int32_t mymap, u_int32_t hismap)
  {
    struct ttydevice *dev = device2tty(p->handler);
    char asyncpath[NG_PATHSIZ];
    struct ng_async_cfg cfg;
  
    if (isngtty(dev)) {
      /* Configure the async converter node */
  
      snprintf(asyncpath, sizeof asyncpath, ".:%s", dev->hook);
      memset(&cfg, 0, sizeof cfg);
      cfg.enabled = 1;
      cfg.accm = mymap | hismap;
      cfg.amru = MAX_MTU;
      cfg.smru = MAX_MRU;
      log_Printf(LogDEBUG, "Configure async node at %s\n", asyncpath);
      if (NgSendMsg(dev->cs, asyncpath, NGM_ASYNC_COOKIE,
                    NGM_ASYNC_CMD_SET_CONFIG, &cfg, sizeof cfg) < 0)
        log_Printf(LogWARN, "%s: Can't configure async node at %s\n",
                   p->link.name, asyncpath);
    } else
      /* No netgraph node, just config the async layer */
      async_SetLinkParams(&p->async, mymap, hismap);
  }
  
  static int
  LoadLineDiscipline(struct physical *p)
  {
    struct ttydevice *dev = device2tty(p->handler);
    u_char rbuf[sizeof(struct ng_mesg) + sizeof(struct nodeinfo)];
    struct ng_mesg *reply;
    struct nodeinfo *info;
    char ttypath[NG_NODESIZ];
    struct ngm_mkpeer ngm;
    struct ngm_connect ngc;
    int ldisc, cs, ds, hot;
    unsigned speed;
  
    /*
     * Don't use the netgraph line discipline for now.  Using it works, but
     * carrier cannot be detected via TIOCMGET and the device doesn't become
     * selectable with 0 bytes to read when carrier is lost :(
     */
    return 0;
  
    reply = (struct ng_mesg *)rbuf;
    info = (struct nodeinfo *)reply->data;
  
    loadmodules(LOAD_VERBOSLY, "netgraph", "ng_tty", "ng_async", "ng_socket",
                NULL);
  
    /* Get the speed before loading the line discipline */
    speed = physical_GetSpeed(p);
  
    if (ioctl(p->fd, TIOCGETD, &dev->real.disc) < 0) {
      log_Printf(LogDEBUG, "%s: Couldn't get tty line discipline\n",
                 p->link.name);
      return 0;
    }
    ldisc = NETGRAPHDISC;
    if (ID0ioctl(p->fd, TIOCSETD, &ldisc) < 0) {
      log_Printf(LogDEBUG, "%s: Couldn't set NETGRAPHDISC line discipline\n",
                 p->link.name);
      return 0;
    }
  
    /* Get the name of the tty node */
    if (ioctl(p->fd, NGIOCGINFO, info) < 0) {
      log_Printf(LogWARN, "%s: ioctl(NGIOCGINFO): %s\n", p->link.name,
                 strerror(errno));
      ID0ioctl(p->fd, TIOCSETD, &dev->real.disc);
      return 0;
    }
    snprintf(ttypath, sizeof ttypath, "%s:", info->name);
  
    /* Create a socket node for our endpoint (and to send messages via) */
    if (ID0NgMkSockNode(NULL, &cs, &ds) == -1) {
      log_Printf(LogWARN, "%s: NgMkSockNode: %s\n", p->link.name,
                 strerror(errno));
      ID0ioctl(p->fd, TIOCSETD, &dev->real.disc);
      return 0;
    }
  
    /* Set the ``hot char'' on the TTY node */
    hot = HDLC_SYN;
    log_Printf(LogDEBUG, "%s: Set tty hotchar to 0x%02x\n", p->link.name, hot);
    if (NgSendMsg(cs, ttypath, NGM_TTY_COOKIE,
        NGM_TTY_SET_HOTCHAR, &hot, sizeof hot) < 0) {
      log_Printf(LogWARN, "%s: Can't set hot char\n", p->link.name);
      goto failed;
    }
  
    /* Attach an async converter node */
    snprintf(ngm.type, sizeof ngm.type, "%s", NG_ASYNC_NODE_TYPE);
    snprintf(ngm.ourhook, sizeof ngm.ourhook, "%s", NG_TTY_HOOK);
    snprintf(ngm.peerhook, sizeof ngm.peerhook, "%s", NG_ASYNC_HOOK_ASYNC);
    log_Printf(LogDEBUG, "%s: Send mkpeer async:%s to %s:%s\n", p->link.name,
               ngm.peerhook, ttypath, ngm.ourhook);
    if (NgSendMsg(cs, ttypath, NGM_GENERIC_COOKIE,
        NGM_MKPEER, &ngm, sizeof ngm) < 0) {
      log_Printf(LogWARN, "%s: Can't create %s node\n", p->link.name,
                 NG_ASYNC_NODE_TYPE);
      goto failed;
    }
  
    /* Connect the async node to our socket */
    snprintf(ngc.path, sizeof ngc.path, "%s%s", ttypath, NG_TTY_HOOK);
    snprintf(ngc.peerhook, sizeof ngc.peerhook, "%s", NG_ASYNC_HOOK_SYNC);
    memcpy(ngc.ourhook, ngc.peerhook, sizeof ngc.ourhook);
    log_Printf(LogDEBUG, "%s: Send connect %s:%s to .:%s\n", p->link.name,
               ngc.path, ngc.peerhook, ngc.ourhook);
    if (NgSendMsg(cs, ".:", NGM_GENERIC_COOKIE, NGM_CONNECT,
        &ngc, sizeof ngc) < 0) {
      log_Printf(LogWARN, "%s: Can't connect .:%s -> %s.%s: %s\n",
                 p->link.name, ngc.ourhook, ngc.path, ngc.peerhook,
                 strerror(errno));
      goto failed;
    }
  
    /* Get the async node id */
    if (NgSendMsg(cs, ngc.path, NGM_GENERIC_COOKIE, NGM_NODEINFO, NULL, 0) < 0) {
      log_Printf(LogWARN, "%s: Can't request async node info at %s: %s\n",
                 p->link.name, ngc.path, strerror(errno));
      goto failed;
    }
    if (NgRecvMsg(cs, reply, sizeof rbuf, NULL) < 0) {
      log_Printf(LogWARN, "%s: Can't obtain async node info at %s: %s\n",
                 p->link.name, ngc.path, strerror(errno));
      goto failed;
    }
  
    /* All done, set up our device state */
    snprintf(dev->hook, sizeof dev->hook, "%s", ngc.ourhook);
    dev->cs = cs;
    dev->real.fd = p->fd;
    p->fd = ds;
    dev->real.speed = speed;
    physical_SetSync(p);
  
    tty_SetAsyncParams(p, 0xffffffff, 0xffffffff);
    physical_SetupStack(p, dev->dev.name, PHYSICAL_NOFORCE);
    log_Printf(LogPHASE, "%s: Loaded netgraph tty line discipline\n",
               p->link.name);
  
    return 1;
  
  failed:
    ID0ioctl(p->fd, TIOCSETD, &dev->real.disc);
    close(ds);
    close(cs);
  
    return 0;
  }
  
  static void
  UnloadLineDiscipline(struct physical *p)
  {
    struct ttydevice *dev = device2tty(p->handler);
  
    if (isngtty(dev)) {
      if (!physical_SetSpeed(p, dev->real.speed))
        log_Printf(LogWARN, "Couldn't reset tty speed to %d\n", dev->real.speed);
      dev->real.speed = 0;
      close(p->fd);
      p->fd = dev->real.fd;
      dev->real.fd = -1;
      close(dev->cs);
      dev->cs = -1;
      *dev->hook = '\0';
      if (ID0ioctl(p->fd, TIOCSETD, &dev->real.disc) == 0) {
        physical_SetupStack(p, dev->dev.name, PHYSICAL_NOFORCE);
        log_Printf(LogPHASE, "%s: Unloaded netgraph tty line discipline\n",
                   p->link.name);
      } else
        log_Printf(LogWARN, "%s: Failed to unload netgraph tty line discipline\n",
                   p->link.name);
    }
  }
  
  static ssize_t
  tty_Write(struct physical *p, const void *v, size_t n)
  {
    struct ttydevice *dev = device2tty(p->handler);
  
    if (isngtty(dev))
      return NgSendData(p->fd, dev->hook, v, n) == -1 ? -1 : (ssize_t)n;
    else
      return write(p->fd, v, n);
  }
  
  static ssize_t
  tty_Read(struct physical *p, void *v, size_t n)
  {
    struct ttydevice *dev = device2tty(p->handler);
    char hook[sizeof NG_ASYNC_HOOK_SYNC];
  
    if (isngtty(dev))
      return NgRecvData(p->fd, v, n, hook);
    else
      return read(p->fd, v, n);
  }
  
  #endif /* NETGRAPH */
  
  static int
  tty_Raw(struct physical *p)
  {
    struct ttydevice *dev = device2tty(p->handler);
    struct termios ios;
    int oldflag;
  
    log_Printf(LogDEBUG, "%s: Entering tty_Raw\n", p->link.name);
  
    if (p->type != PHYS_DIRECT && p->fd >= 0 && !Online(dev))
      log_Printf(LogDEBUG, "%s: Raw: descriptor = %d, mbits = %x\n",
                p->link.name, p->fd, dev->mbits);
  
    if (!physical_IsSync(p)) {
  #ifndef NONETGRAPH
      if (!LoadLineDiscipline(p))
  #endif
      {
        tcgetattr(p->fd, &ios);
        cfmakeraw(&ios);
        if (p->cfg.rts_cts)
          ios.c_cflag |= CLOCAL | CCTS_OFLOW | CRTS_IFLOW;
        else
          ios.c_cflag |= CLOCAL;
  
        if (p->type != PHYS_DEDICATED)
          ios.c_cflag |= HUPCL;
  
        if (tcsetattr(p->fd, TCSANOW, &ios) == -1)
          log_Printf(LogWARN, "%s: tcsetattr: Failed configuring device\n",
                     p->link.name);
      }
    }
  
    oldflag = fcntl(p->fd, F_GETFL, 0);
    if (oldflag < 0)
      return 0;
    fcntl(p->fd, F_SETFL, oldflag | O_NONBLOCK);
  
    return 1;
  }
  
  static void
  tty_Offline(struct physical *p)
  {
    struct ttydevice *dev = device2tty(p->handler);
  
    if (p->fd >= 0) {
      timer_Stop(&dev->Timer);
      dev->mbits &= ~TIOCM_DTR;	/* XXX: Hmm, what's this supposed to do ? */
      if (Online(dev)) {
        struct termios tio;
  
        tcgetattr(p->fd, &tio);
        if (cfsetspeed(&tio, B0) == -1 || tcsetattr(p->fd, TCSANOW, &tio) == -1)
          log_Printf(LogWARN, "%s: Unable to set physical to speed 0\n",
                     p->link.name);
      }
    }
  }
  
  static void
  tty_Cooked(struct physical *p)
  {
    struct ttydevice *dev = device2tty(p->handler);
    int oldflag;
  
    tty_Offline(p);	/* In case of emergency close()s */
  
    tcflush(p->fd, TCIOFLUSH);
  
    if (!physical_IsSync(p) && tcsetattr(p->fd, TCSAFLUSH, &dev->ios) == -1)
      log_Printf(LogWARN, "%s: tcsetattr: Unable to restore device settings\n",
                 p->link.name);
  
  #ifndef NONETGRAPH
    UnloadLineDiscipline(p);
  #endif
  
    if ((oldflag = fcntl(p->fd, F_GETFL, 0)) != -1)
      fcntl(p->fd, F_SETFL, oldflag & ~O_NONBLOCK);
  }
  
  static void
  tty_StopTimer(struct physical *p)
  {
    struct ttydevice *dev = device2tty(p->handler);
  
    timer_Stop(&dev->Timer);
  }
  
  static void
  tty_Free(struct physical *p)
  {
    struct ttydevice *dev = device2tty(p->handler);
  
    tty_Offline(p);	/* In case of emergency close()s */
    free(dev);
  }
  
  static unsigned
  tty_Speed(struct physical *p)
  {
    struct termios ios;
  
    if (tcgetattr(p->fd, &ios) == -1)
      return 0;
  
    return SpeedToUnsigned(cfgetispeed(&ios));
  }
  
  static const char *
  tty_OpenInfo(struct physical *p)
  {
    struct ttydevice *dev = device2tty(p->handler);
    static char buf[13];
  
    if (Online(dev))
      strcpy(buf, "with");
    else
      strcpy(buf, "no");
    strcat(buf, " carrier");
  
    return buf;
  }
  
  static int
  tty_Slot(struct physical *p)
  {
    struct ttyent *ttyp;
    int slot;
  
    setttyent();
    for (slot = 1; (ttyp = getttyent()); ++slot)
      if (!strcmp(ttyp->ty_name, p->name.base)) {
        endttyent();
        return slot;
      }
  
    endttyent();
    return -1;
  }
  
  static void
  tty_device2iov(struct device *d, struct iovec *iov, int *niov,
                 int maxiov __unused,
  #ifndef NONETGRAPH
                 int *auxfd, int *nauxfd
  #else
                 int *auxfd __unused, int *nauxfd __unused
  #endif
                 )
  {
    struct ttydevice *dev;
    int sz = physical_MaxDeviceSize();
  
    iov[*niov].iov_base = d = realloc(d, sz);
    if (d == NULL) {
      log_Printf(LogALERT, "Failed to allocate memory: %d\n", sz);
      AbortProgram(EX_OSERR);
    }
    iov[*niov].iov_len = sz;
    (*niov)++;
  
    dev = device2tty(d);
  
  #ifndef NONETGRAPH
    if (dev->cs >= 0) {
      *auxfd = dev->cs;
      (*nauxfd)++;
    }
  #endif
  
    if (dev->Timer.state != TIMER_STOPPED) {
      timer_Stop(&dev->Timer);
      dev->Timer.state = TIMER_RUNNING;
    }
  }
  
  static struct device basettydevice = {
    TTY_DEVICE,
    "tty",
    0,
    { CD_VARIABLE, DEF_TTYCDDELAY },
    tty_AwaitCarrier,
    NULL,
    tty_Raw,
    tty_Offline,
    tty_Cooked,
    tty_SetAsyncParams,
    tty_StopTimer,
    tty_Free,
    tty_Read,
    tty_Write,
    tty_device2iov,
    tty_Speed,
    tty_OpenInfo,
    tty_Slot
  };
  
  struct device *
  tty_iov2device(int type, struct physical *p, struct iovec *iov, int *niov,
                 int maxiov __unused,
  #ifndef NONETGRAPH
                 int *auxfd, int *nauxfd
  #else
                 int *auxfd __unused, int *nauxfd __unused
  #endif
                 )
  {
    if (type == TTY_DEVICE) {
      struct ttydevice *dev = (struct ttydevice *)iov[(*niov)++].iov_base;
  
      dev = realloc(dev, sizeof *dev);	/* Reduce to the correct size */
      if (dev == NULL) {
        log_Printf(LogALERT, "Failed to allocate memory: %d\n",
                   (int)(sizeof *dev));
        AbortProgram(EX_OSERR);
      }
  
  #ifndef NONETGRAPH
      if (*nauxfd) {
        dev->cs = *auxfd;
        (*nauxfd)--;
      } else
        dev->cs = -1;
  #endif
  
      /* Refresh function pointers etc */
      memcpy(&dev->dev, &basettydevice, sizeof dev->dev);
  
      physical_SetupStack(p, dev->dev.name, PHYSICAL_NOFORCE);
      if (dev->Timer.state != TIMER_STOPPED) {
        dev->Timer.state = TIMER_STOPPED;
        p->handler = &dev->dev;		/* For the benefit of StartTimer */
        tty_StartTimer(p);
      }
      return &dev->dev;
    }
  
    return NULL;
  }
  
  struct device *
  tty_Create(struct physical *p)
  {
    struct ttydevice *dev;
    struct termios ios;
    int oldflag;
  
    if (p->fd < 0 || !isatty(p->fd))
      /* Don't want this */
      return NULL;
  
    if (*p->name.full == '\0') {
      physical_SetDevice(p, ttyname(p->fd));
      log_Printf(LogDEBUG, "%s: Input is a tty (%s)\n",
                 p->link.name, p->name.full);
    } else
      log_Printf(LogDEBUG, "%s: Opened %s\n", p->link.name, p->name.full);
  
    /* We're gonna return a ttydevice (unless something goes horribly wrong) */
  
    if ((dev = malloc(sizeof *dev)) == NULL) {
      /* Complete failure - parent doesn't continue trying to ``create'' */
      close(p->fd);
      p->fd = -1;
      return NULL;
    }
  
    memcpy(&dev->dev, &basettydevice, sizeof dev->dev);
    memset(&dev->Timer, '\0', sizeof dev->Timer);
    dev->mbits = -1;
  #ifndef NONETGRAPH
    dev->real.speed = 0;
    dev->real.fd = -1;
    dev->real.disc = -1;
    *dev->hook = '\0';
  #endif
    tcgetattr(p->fd, &ios);
    dev->ios = ios;
  
    if (p->cfg.cd.necessity != CD_DEFAULT)
      /* Any override is ok for the tty device */
      dev->dev.cd = p->cfg.cd;
  
    log_Printf(LogDEBUG, "%s: tty_Create: physical (get): fd = %d,"
               " iflag = %lx, oflag = %lx, cflag = %lx\n", p->link.name, p->fd,
               (u_long)ios.c_iflag, (u_long)ios.c_oflag, (u_long)ios.c_cflag);
  
    cfmakeraw(&ios);
    if (p->cfg.rts_cts)
      ios.c_cflag |= CLOCAL | CCTS_OFLOW | CRTS_IFLOW;
    else {
      ios.c_cflag |= CLOCAL;
      ios.c_iflag |= IXOFF;
    }
    ios.c_iflag |= IXON;
    if (p->type != PHYS_DEDICATED)
      ios.c_cflag |= HUPCL;
  
    if (p->type != PHYS_DIRECT) {
        /* Change tty speed when we're not in -direct mode */
        ios.c_cflag &= ~(CSIZE | PARODD | PARENB);
        ios.c_cflag |= p->cfg.parity;
        if (cfsetspeed(&ios, UnsignedToSpeed(p->cfg.speed)) == -1)
  	log_Printf(LogWARN, "%s: %s: Unable to set speed to %d\n",
  		  p->link.name, p->name.full, p->cfg.speed);
    }
  
    if (tcsetattr(p->fd, TCSADRAIN, &ios) == -1) {
      log_Printf(LogWARN, "%s: tcsetattr: Failed configuring device\n",
                 p->link.name);
      if (p->type != PHYS_DIRECT && p->cfg.speed > 115200)
        log_Printf(LogWARN, "%.*s             Perhaps the speed is unsupported\n",
                   (int)strlen(p->link.name), "");
    }
  
    log_Printf(LogDEBUG, "%s: physical (put): iflag = %lx, oflag = %lx, "
              "cflag = %lx\n", p->link.name, (u_long)ios.c_iflag,
              (u_long)ios.c_oflag, (u_long)ios.c_cflag);
  
    oldflag = fcntl(p->fd, F_GETFL, 0);
    if (oldflag < 0) {
      /* Complete failure - parent doesn't continue trying to ``create'' */
  
      log_Printf(LogWARN, "%s: Open: Cannot get physical flags: %s\n",
                 p->link.name, strerror(errno));
      tty_Cooked(p);
      close(p->fd);
      p->fd = -1;
      free(dev);
      return NULL;
    } else
      fcntl(p->fd, F_SETFL, oldflag & ~O_NONBLOCK);
  
    physical_SetupStack(p, dev->dev.name, PHYSICAL_NOFORCE);
  
    return &dev->dev;
  }
  