text: /*
   * Copyright (c) 1988 The Regents of the University of California.
   * 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.
   * 3. All advertising materials mentioning features or use of this software
   *    must display the following acknowledgement:
   *	This product includes software developed by the University of
   *	California, Berkeley and its contributors.
   * 4. Neither the name of the University nor the names of its contributors
   *    may be used to endorse or promote products derived from this software
   *    without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
   */
  
  #if defined(LIBC_SCCS) && !defined(lint)
  static char sccsid[] = "@(#)ttyname.c	5.10 (Berkeley) 5/6/91";
  #endif /* LIBC_SCCS and not lint */
  
  #include "config.h"
  #include <pthread.h>
  #include <sys/types.h>
  #include <sys/stat.h>
  #include <fcntl.h>
  #include <dirent.h>
  #include <unistd.h>
  #include <string.h>
  #include <stdlib.h>
  
  static pthread_mutex_t ttyname_lock = PTHREAD_MUTEX_INITIALIZER;
  static pthread_key_t ttyname_key;
  static int ttyname_init = 0;
  extern void free();
  
  char * __ttyname_r_basic(int fd, char * buf, size_t len)
  {
  	register struct dirent *dirp;
  	register DIR *dp;
  	struct stat dsb;
  	struct stat sb;
  	char * rval;
  	int minlen;
  
      rval = NULL;
  
  	/* Must be a terminal. */
  	if (! isatty_basic(fd))
  		return(rval);
  	/* Must be a character device. */
  	if (machdep_sys_fstat(fd, &sb) || !S_ISCHR(sb.st_mode))
  		return(rval);
  	/* Must have enough room */
      if (len <= sizeof(_PATH_PTY)) 
  		return(rval);
  
  	if ((dp = opendir(_PATH_PTY)) != NULL) {
  		memcpy(buf, _PATH_PTY, sizeof(_PATH_PTY));
  		for (rval = NULL; dirp = readdir(dp);) {
  			if (dirp->d_fileno != sb.st_ino)
  				continue;
  			minlen = (len - (sizeof(_PATH_PTY) - 1)) < (dirp->d_namlen + 1) ?
  			  (len - (sizeof(_PATH_PTY) - 1)) : (dirp->d_namlen + 1);
  			memcpy (buf + sizeof(_PATH_PTY) - 1, dirp->d_name, minlen);
  			if (stat(buf, &dsb) || sb.st_dev != dsb.st_dev ||
  	    		sb.st_ino != dsb.st_ino)
  				continue;
  			rval = buf;
  			break;
  		}
  		(void)closedir(dp);
  	}
  	return(rval);
  }
  
  char * __ttyname_basic(int fd)
  {
  	char *buf;
  
  	pthread_mutex_lock (&ttyname_lock);
  	if (ttyname_init == 0) {
  		if (pthread_key_create(&ttyname_key, free)) {
  			pthread_mutex_unlock (&ttyname_lock);
  			return(NULL);
  		}
  		ttyname_init = 1;
  	}
  	pthread_mutex_unlock (&ttyname_lock);
  
  	/* Must have thread specific data field to put data */
      if ((buf = pthread_getspecific(ttyname_key)) == NULL) {
  		if (buf = malloc(sizeof(_PATH_PTY) + MAXNAMLEN)) {
  			if (pthread_setspecific(ttyname_key, buf) != OK) {
  				free(buf);
  				return(NULL);
  			}
  		} else {
  			return(NULL);
  		}
  	}
  	return(__ttyname_r_basic(fd, buf, sizeof(_PATH_PTY) + MAXNAMLEN));
  }
  
  char * ttyname_r(int fd, char * buf, size_t len)
  {
  	char * ret;
  
  	if (fd_lock(fd, FD_READ) == OK) {
       	ret = __ttyname_r_basic(fd_table[fd]->fd.i, buf, len);
  		fd_unlock(fd, FD_READ);
  	} else {
  		ret = NULL;
  	}
  	return(ret);
  }
  
  char * ttyname(int fd)
  {
  	char * ret;
  
  	if (fd_lock(fd, FD_READ) == OK) {
       	ret = __ttyname_basic(fd_table[fd]->fd.i);
  		fd_unlock(fd, FD_READ);
  	} else {
  		ret = NULL;
  	}
  	return(ret);
  }
  
  
  