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getttyent.c revision 1.4 
      1 /*
      2  * Copyright (c) 1989 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 #if defined(LIBC_SCCS) && !defined(lint)
     35 /*static char *sccsid = "from: @(#)getttyent.c	5.10 (Berkeley) 3/23/91";*/
     36 static char *rcsid = "$Id: getttyent.c,v 1.4 1993/11/24 19:43:56 jtc Exp $";
     37 #endif /* LIBC_SCCS and not lint */
     38 
     39 #include <ttyent.h>
     40 #include <stdio.h>
     41 #include <ctype.h>
     42 #include <string.h>
     43 
     44 static char zapchar;
     45 static FILE *tf;
     46 
     47 struct ttyent *
     48 getttynam(tty)
     49 	const char *tty;
     50 {
     51 	register struct ttyent *t;
     52 
     53 	setttyent();
     54 	while (t = getttyent())
     55 		if (!strcmp(tty, t->ty_name))
     56 			break;
     57 	endttyent();
     58 	return (t);
     59 }
     60 
     61 struct ttyent *
     62 getttyent()
     63 {
     64 	static struct ttyent tty;
     65 	register int c;
     66 	register char *p;
     67 #define	MAXLINELENGTH	100
     68 	static char line[MAXLINELENGTH];
     69 	static char *skip(), *value();
     70 
     71 	if (!tf && !setttyent())
     72 		return (NULL);
     73 	for (;;) {
     74 		if (!fgets(p = line, sizeof(line), tf))
     75 			return (NULL);
     76 		/* skip lines that are too big */
     77 		if (!strchr(p, '\n')) {
     78 			while ((c = getc(tf)) != '\n' && c != EOF)
     79 				;
     80 			continue;
     81 		}
     82 		while (isspace(*p))
     83 			++p;
     84 		if (*p && *p != '#')
     85 			break;
     86 	}
     87 
     88 	zapchar = 0;
     89 	tty.ty_name = p;
     90 	p = skip(p);
     91 	if (!*(tty.ty_getty = p))
     92 		tty.ty_getty = tty.ty_type = NULL;
     93 	else {
     94 		p = skip(p);
     95 		if (!*(tty.ty_type = p))
     96 			tty.ty_type = NULL;
     97 		else
     98 			p = skip(p);
     99 	}
    100 	tty.ty_status = 0;
    101 	tty.ty_window = NULL;
    102 
    103 #define	scmp(e)	!strncmp(p, e, sizeof(e) - 1) && isspace(p[sizeof(e) - 1])
    104 #define	vcmp(e)	!strncmp(p, e, sizeof(e) - 1) && p[sizeof(e) - 1] == '='
    105 	for (; *p; p = skip(p)) {
    106 		if (scmp(_TTYS_OFF))
    107 			tty.ty_status &= ~TTY_ON;
    108 		else if (scmp(_TTYS_ON))
    109 			tty.ty_status |= TTY_ON;
    110 		else if (scmp(_TTYS_SECURE))
    111 			tty.ty_status |= TTY_SECURE;
    112 		else if (vcmp(_TTYS_WINDOW))
    113 			tty.ty_window = value(p);
    114 		else
    115 			break;
    116 	}
    117 
    118 	if (zapchar == '#' || *p == '#')
    119 		while ((c = *++p) == ' ' || c == '\t')
    120 			;
    121 	tty.ty_comment = p;
    122 	if (*p == 0)
    123 		tty.ty_comment = 0;
    124 	if (p = strchr(p, '\n'))
    125 		*p = '\0';
    126 	return (&tty);
    127 }
    128 
    129 #define	QUOTED	1
    130 
    131 /*
    132  * Skip over the current field, removing quotes, and return a pointer to
    133  * the next field.
    134  */
    135 static char *
    136 skip(p)
    137 	register char *p;
    138 {
    139 	register char *t;
    140 	register int c, q;
    141 
    142 	for (q = 0, t = p; (c = *p) != '\0'; p++) {
    143 		if (c == '"') {
    144 			q ^= QUOTED;	/* obscure, but nice */
    145 			continue;
    146 		}
    147 		if (q == QUOTED && *p == '\\' && *(p+1) == '"')
    148 			p++;
    149 		*t++ = *p;
    150 		if (q == QUOTED)
    151 			continue;
    152 		if (c == '#') {
    153 			zapchar = c;
    154 			*p = 0;
    155 			break;
    156 		}
    157 		if (c == '\t' || c == ' ' || c == '\n') {
    158 			zapchar = c;
    159 			*p++ = 0;
    160 			while ((c = *p) == '\t' || c == ' ' || c == '\n')
    161 				p++;
    162 			break;
    163 		}
    164 	}
    165 	*--t = '\0';
    166 	return (p);
    167 }
    168 
    169 static char *
    170 value(p)
    171 	register char *p;
    172 {
    173 
    174 	return ((p = strchr(p, '=')) ? ++p : NULL);
    175 }
    176 
    177 int
    178 setttyent()
    179 {
    180 
    181 	if (tf) {
    182 		(void)rewind(tf);
    183 		return (1);
    184 	} else if (tf = fopen(_PATH_TTYS, "r"))
    185 		return (1);
    186 	return (0);
    187 }
    188 
    189 int
    190 endttyent()
    191 {
    192 	int rval;
    193 
    194 	if (tf) {
    195 		rval = !(fclose(tf) == EOF);
    196 		tf = NULL;
    197 		return (rval);
    198 	}
    199 	return (1);
    200 }
    201