misc/ttyslot.c

   1 /*
   2  * Copyright (c) 1988, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgement:
  15  *      This product includes software developed by the University of
  16  *      California, Berkeley and its contributors.
  17  * 4. Neither the name of the University nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 #if defined(LIBC_SCCS) && !defined(lint)
  35 static char sccsid[] = "@(#)ttyslot.c   8.1 (Berkeley) 6/4/93";
  36 #endif /* LIBC_SCCS and not lint */
  37
  38 #include <ttyent.h>
  39 #include <alloca.h>
  40 #include <stdio.h>
  41 #include <string.h>
  42 #include <unistd.h>
  43
  44 int
  45 ttyslot()
  46 {
  47         register struct ttyent *ttyp;
  48         register int slot;
  49         register char *p;
  50         int cnt;
  51         size_t buflen = __sysconf (_SC_TTY_NAME_MAX) + 1;
  52         char *name;
  53
  54         if (buflen == 0)
  55           /* This should be enough if no fixed value is given.  */
  56           buflen = 32;
  57
  58         name = __alloca (buflen);
  59
  60         setttyent();
  61         for (cnt = 0; cnt < 3; ++cnt)
  62                 if (__ttyname_r (cnt, name, buflen) == 0) {
  63                         if (p = rindex(name, '/'))
  64                                 ++p;
  65                         else
  66                                 p = name;
  67                         for (slot = 1; ttyp = getttyent(); ++slot)
  68                                 if (!strcmp(ttyp->ty_name, p)) {
  69                                         endttyent();
  70                                         return(slot);
  71                                 }
  72                         break;
  73                 }
  74         endttyent();
  75         return(0);
  76 }