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glibc  2.9
ttyslot.c
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00001 /*
00002  * Copyright (c) 1988, 1993
00003  *     The Regents of the University of California.  All rights reserved.
00004  *
00005  * Redistribution and use in source and binary forms, with or without
00006  * modification, are permitted provided that the following conditions
00007  * are met:
00008  * 1. Redistributions of source code must retain the above copyright
00009  *    notice, this list of conditions and the following disclaimer.
00010  * 2. Redistributions in binary form must reproduce the above copyright
00011  *    notice, this list of conditions and the following disclaimer in the
00012  *    documentation and/or other materials provided with the distribution.
00013  * 4. Neither the name of the University nor the names of its contributors
00014  *    may be used to endorse or promote products derived from this software
00015  *    without specific prior written permission.
00016  *
00017  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
00018  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
00019  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
00020  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
00021  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
00022  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
00023  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
00024  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
00025  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
00026  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
00027  * SUCH DAMAGE.
00028  */
00029 
00030 #if defined(LIBC_SCCS) && !defined(lint)
00031 static char sccsid[] = "@(#)ttyslot.c     8.1 (Berkeley) 6/4/93";
00032 #endif /* LIBC_SCCS and not lint */
00033 
00034 #include <ttyent.h>
00035 #include <alloca.h>
00036 #include <stdio.h>
00037 #include <string.h>
00038 #include <unistd.h>
00039 
00040 int
00041 ttyslot()
00042 {
00043        register struct ttyent *ttyp;
00044        register int slot;
00045        register char *p;
00046        int cnt;
00047        size_t buflen = __sysconf (_SC_TTY_NAME_MAX) + 1;
00048        char *name;
00049 
00050        if (buflen == 0)
00051          /* This should be enough if no fixed value is given.  */
00052          buflen = 32;
00053 
00054        name = __alloca (buflen);
00055 
00056        setttyent();
00057        for (cnt = 0; cnt < 3; ++cnt)
00058               if (__ttyname_r (cnt, name, buflen) == 0) {
00059                      if ((p = rindex(name, '/')))
00060                             ++p;
00061                      else
00062                             p = name;
00063                      for (slot = 1; (ttyp = getttyent()); ++slot)
00064                             if (!strcmp(ttyp->ty_name, p)) {
00065                                    endttyent();
00066                                    return(slot);
00067                             }
00068                      break;
00069               }
00070        endttyent();
00071        return(0);
00072 }