vars.c revision 1590 
1/*
2 * Copyright (c) 1980, 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#ifndef lint
35static char sccsid[] = "@(#)vars.c	8.1 (Berkeley) 6/6/93";
36#endif /* not lint */
37
38#include "rcv.h"
39#include "extern.h"
40
41/*
42 * Mail -- a mail program
43 *
44 * Variable handling stuff.
45 */
46
47/*
48 * Assign a value to a variable.
49 */
50void
51assign(name, value)
52	char name[], value[];
53{
54	register struct var *vp;
55	register int h;
56
57	h = hash(name);
58	vp = lookup(name);
59	if (vp == NOVAR) {
60		vp = (struct var *) calloc(sizeof *vp, 1);
61		vp->v_name = vcopy(name);
62		vp->v_link = variables[h];
63		variables[h] = vp;
64	}
65	else
66		vfree(vp->v_value);
67	vp->v_value = vcopy(value);
68}
69
70/*
71 * Free up a variable string.  We do not bother to allocate
72 * strings whose value is "" since they are expected to be frequent.
73 * Thus, we cannot free same!
74 */
75void
76vfree(cp)
77	char *cp;
78{
79	if (*cp)
80		free(cp);
81}
82
83/*
84 * Copy a variable value into permanent (ie, not collected after each
85 * command) space.  Do not bother to alloc space for ""
86 */
87
88char *
89vcopy(str)
90	char str[];
91{
92	char *new;
93	unsigned len;
94
95	if (*str == '\0')
96		return "";
97	len = strlen(str) + 1;
98	if ((new = malloc(len)) == NULL)
99		panic("Out of memory");
100	bcopy(str, new, (int) len);
101	return new;
102}
103
104/*
105 * Get the value of a variable and return it.
106 * Look in the environment if its not available locally.
107 */
108
109char *
110value(name)
111	char name[];
112{
113	register struct var *vp;
114
115	if ((vp = lookup(name)) == NOVAR)
116		return(getenv(name));
117	return(vp->v_value);
118}
119
120/*
121 * Locate a variable and return its variable
122 * node.
123 */
124
125struct var *
126lookup(name)
127	register char name[];
128{
129	register struct var *vp;
130
131	for (vp = variables[hash(name)]; vp != NOVAR; vp = vp->v_link)
132		if (*vp->v_name == *name && equal(vp->v_name, name))
133			return(vp);
134	return(NOVAR);
135}
136
137/*
138 * Locate a group name and return it.
139 */
140
141struct grouphead *
142findgroup(name)
143	register char name[];
144{
145	register struct grouphead *gh;
146
147	for (gh = groups[hash(name)]; gh != NOGRP; gh = gh->g_link)
148		if (*gh->g_name == *name && equal(gh->g_name, name))
149			return(gh);
150	return(NOGRP);
151}
152
153/*
154 * Print a group out on stdout
155 */
156void
157printgroup(name)
158	char name[];
159{
160	register struct grouphead *gh;
161	register struct group *gp;
162
163	if ((gh = findgroup(name)) == NOGRP) {
164		printf("\"%s\": not a group\n", name);
165		return;
166	}
167	printf("%s\t", gh->g_name);
168	for (gp = gh->g_list; gp != NOGE; gp = gp->ge_link)
169		printf(" %s", gp->ge_name);
170	putchar('\n');
171}
172
173/*
174 * Hash the passed string and return an index into
175 * the variable or group hash table.
176 */
177int
178hash(name)
179	register char *name;
180{
181	register h = 0;
182
183	while (*name) {
184		h <<= 2;
185		h += *name++;
186	}
187	if (h < 0 && (h = -h) < 0)
188		h = 0;
189	return (h % HSHSIZE);
190}
191