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term.c revision 1.4 
      1 /*-
      2  * Copyright (c) 1991 The Regents of the University of California.
      3  * 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 #ifndef lint
     35 static char sccsid[] = "@(#)term.c	5.5 (Berkeley) 5/11/92";
     36 #endif /* not lint */
     37 
     38 #include <sys/types.h>
     39 #include <errno.h>
     40 #include <ttyent.h>
     41 #include <unistd.h>
     42 #include <stdio.h>
     43 #include <stdlib.h>
     44 #include <string.h>
     45 #include "extern.h"
     46 
     47 char    tbuf[1024];      		/* Termcap entry. */
     48 
     49 char	*askuser __P((char *));
     50 char	*ttys __P((char *));
     51 
     52 /*
     53  * Figure out what kind of terminal we're dealing with, and then read in
     54  * its termcap entry.
     55  */
     56 char *
     57 get_termcap_entry(userarg, tcapbufp)
     58 	char *userarg, **tcapbufp;
     59 {
     60 	struct ttyent *t;
     61 	int rval;
     62 	char *p, *ttype, *ttypath;
     63 
     64 	if (userarg) {
     65 		ttype = userarg;
     66 		goto found;
     67 	}
     68 
     69 	/* Try the environment. */
     70 	if (ttype = getenv("TERM"))
     71 		goto map;
     72 
     73 	/* Try ttyname(3); check for dialup or other mapping. */
     74 	if (ttypath = ttyname(STDERR_FILENO)) {
     75 		if (p = rindex(ttypath, '/'))
     76 			++p;
     77 		else
     78 			p = ttypath;
     79 		if ((t = getttynam(p))) {
     80 			ttype = t->ty_type;
     81 			goto map;
     82 		}
     83 	}
     84 
     85 	/* If still undefined, use "unknown". */
     86 	ttype = "unknown";
     87 
     88 map:	ttype = mapped(ttype);
     89 
     90 	/*
     91 	 * If not a path, remove TERMCAP from the environment so we get a
     92 	 * real entry from /etc/termcap.  This prevents us from being fooled
     93 	 * by out of date stuff in the environment.
     94 	 */
     95 found:	if ((p = getenv("TERMCAP")) != NULL && *p != '/')
     96 		unsetenv("TERMCAP");
     97 
     98 	/*
     99 	 * ttype now contains a pointer to the type of the terminal.
    100 	 * If the first character is '?', ask the user.
    101 	 */
    102 	if (ttype[0] == '?')
    103 		if (ttype[1] != '\0')
    104 			ttype = askuser(ttype + 1);
    105 		else
    106 			ttype = askuser(NULL);
    107 
    108 	/* Find the termcap entry.  If it doesn't exist, ask the user. */
    109 	while ((rval = tgetent(tbuf, ttype)) == 0) {
    110 		(void)fprintf(stderr,
    111 		    "tset: terminal type %s is unknown\n", ttype);
    112 		ttype = askuser(NULL);
    113 	}
    114 	if (rval == -1)
    115 		err("termcap: %s", strerror(errno ? errno : ENOENT));
    116 	*tcapbufp = tbuf;
    117 	return (ttype);
    118 }
    119 
    120 /* Prompt the user for a terminal type. */
    121 char *
    122 askuser(dflt)
    123 	char *dflt;
    124 {
    125 	static char answer[256];
    126 	char *p;
    127 
    128 	/* We can get recalled; if so, don't continue uselessly. */
    129 	if (feof(stdin) || ferror(stdin)) {
    130 		(void)fprintf(stderr, "\n");
    131 		exit(1);
    132 	}
    133 	for (;;) {
    134 		if (dflt)
    135 			(void)fprintf(stderr, "Terminal type? [%s] ", dflt);
    136 		else
    137 			(void)fprintf(stderr, "Terminal type? ");
    138 		(void)fflush(stderr);
    139 
    140 		if (fgets(answer, sizeof(answer), stdin) == NULL) {
    141 			if (dflt == NULL) {
    142 				(void)fprintf(stderr, "\n");
    143 				exit(1);
    144 			}
    145 			return (dflt);
    146 		}
    147 
    148 		if (p = index(answer, '\n'))
    149 			*p = '\0';
    150 		if (answer[0])
    151 			return (answer);
    152 		if (dflt != NULL)
    153 			return (dflt);
    154 	}
    155 }
    156