text: /* Copyright (C) 1991,92,93,96,97,98,2000,2002 Free Software Foundation, Inc.
     This file is part of the GNU C Library.
  
     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 <limits.h>
  #include <stddef.h>
  #include <dirent.h>
  #include <sys/types.h>
  #include <sys/stat.h>
  #include <unistd.h>
  #include <string.h>
  #include <stdlib.h>
  
  char *__ttyname;
  
  static char *getttyname (int fd, dev_t mydev, ino_t myino,
  			 int save, int *dostat) internal_function;
  
  
  libc_freeres_ptr (static char *getttyname_name);
  
  static char *
  internal_function
  getttyname (fd, mydev, myino, save, dostat)
       int fd;
       dev_t mydev;
       ino_t myino;
       int save;
       int *dostat;
  {
    static const char dev[] = "/dev";
    static size_t namelen;
    struct stat st;
    DIR *dirstream;
    struct dirent *d;
  
    dirstream = __opendir (dev);
    if (dirstream == NULL)
      {
        *dostat = -1;
        return NULL;
      }
  
    while ((d = __readdir (dirstream)) != NULL)
      if (((ino_t) d->d_fileno == myino || *dostat)
  	&& strcmp (d->d_name, "stdin")
  	&& strcmp (d->d_name, "stdout")
  	&& strcmp (d->d_name, "stderr"))
        {
  	size_t dlen = _D_ALLOC_NAMLEN (d);
  	if (sizeof (dev) + dlen > namelen)
  	  {
  	    free (getttyname_name);
  	    namelen = 2 * (sizeof (dev) + dlen); /* Big enough.  */
  	    getttyname_name = malloc (namelen);
  	    if (! getttyname_name)
  	      {
  		*dostat = -1;
  		/* Perhaps it helps to free the directory stream buffer.  */
  		(void) __closedir (dirstream);
  		return NULL;
  	      }
  	    *((char *) __mempcpy (getttyname_name, dev, sizeof (dev) - 1))
  	      = '/';
  	  }
  	(void) __mempcpy (&getttyname_name[sizeof (dev)], d->d_name, dlen);
  	if (stat (getttyname_name, &st) == 0
  #ifdef _STATBUF_ST_RDEV
  	    && S_ISCHR (st.st_mode) && st.st_rdev == mydev
  #else
  	    && (ino_t) d->d_fileno == myino && st.st_dev == mydev
  #endif
  	   )
  	  {
  	    (void) __closedir (dirstream);
  	    __ttyname = getttyname_name;
  	    __set_errno (save);
  	    return getttyname_name;
  	  }
        }
  
    (void) __closedir (dirstream);
    __set_errno (save);
    return NULL;
  }
  
  /* Return the pathname of the terminal FD is open on, or NULL on errors.
     The returned storage is good only until the next call to this function.  */
  char *
  ttyname (fd)
       int fd;
  {
    struct stat st;
    int dostat = 0;
    char *name;
    int save = errno;
  
    if (!__isatty (fd))
      return NULL;
  
    if (fstat (fd, &st) < 0)
      return NULL;
  
  #ifdef _STATBUF_ST_RDEV
    name = getttyname (fd, st.st_rdev, st.st_ino, save, &dostat);
  #else
    name = getttyname (fd, st.st_dev, st.st_ino, save, &dostat);
  #endif
  
    if (!name && dostat != -1)
      {
        dostat = 1;
  #ifdef _STATBUF_ST_RDEV
        name = getttyname (fd, st.st_rdev, st.st_ino, save, &dostat);
  #else
        name = getttyname (fd, st.st_dev, st.st_ino, save, &dostat);
  #endif
      }
  
    return name;
  }
  