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vars.c revision 1.1 
      1 /*
      2  * Copyright (c) 1980 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[] = "@(#)vars.c	5.6 (Berkeley) 6/1/90";
     36 #endif /* not lint */
     37 
     38 #include "rcv.h"
     39 
     40 /*
     41  * Mail -- a mail program
     42  *
     43  * Variable handling stuff.
     44  */
     45 
     46 /*
     47  * Assign a value to a variable.
     48  */
     49 
     50 assign(name, value)
     51 	char name[], value[];
     52 {
     53 	register struct var *vp;
     54 	register int h;
     55 
     56 	h = hash(name);
     57 	vp = lookup(name);
     58 	if (vp == NOVAR) {
     59 		vp = (struct var *) calloc(sizeof *vp, 1);
     60 		vp->v_name = vcopy(name);
     61 		vp->v_link = variables[h];
     62 		variables[h] = vp;
     63 	}
     64 	else
     65 		vfree(vp->v_value);
     66 	vp->v_value = vcopy(value);
     67 }
     68 
     69 /*
     70  * Free up a variable string.  We do not bother to allocate
     71  * strings whose value is "" since they are expected to be frequent.
     72  * Thus, we cannot free same!
     73  */
     74 
     75 vfree(cp)
     76 	char *cp;
     77 {
     78 	if (*cp)
     79 		free(cp);
     80 }
     81 
     82 /*
     83  * Copy a variable value into permanent (ie, not collected after each
     84  * command) space.  Do not bother to alloc space for ""
     85  */
     86 
     87 char *
     88 vcopy(str)
     89 	char str[];
     90 {
     91 	char *new;
     92 	unsigned len;
     93 
     94 	if (*str == '\0')
     95 		return "";
     96 	len = strlen(str) + 1;
     97 	if ((new = malloc(len)) == NULL)
     98 		panic("Out of memory");
     99 	bcopy(str, new, (int) len);
    100 	return new;
    101 }
    102 
    103 /*
    104  * Get the value of a variable and return it.
    105  * Look in the environment if its not available locally.
    106  */
    107 
    108 char *
    109 value(name)
    110 	char name[];
    111 {
    112 	register struct var *vp;
    113 
    114 	if ((vp = lookup(name)) == NOVAR)
    115 		return(getenv(name));
    116 	return(vp->v_value);
    117 }
    118 
    119 /*
    120  * Locate a variable and return its variable
    121  * node.
    122  */
    123 
    124 struct var *
    125 lookup(name)
    126 	register char name[];
    127 {
    128 	register struct var *vp;
    129 
    130 	for (vp = variables[hash(name)]; vp != NOVAR; vp = vp->v_link)
    131 		if (*vp->v_name == *name && equal(vp->v_name, name))
    132 			return(vp);
    133 	return(NOVAR);
    134 }
    135 
    136 /*
    137  * Locate a group name and return it.
    138  */
    139 
    140 struct grouphead *
    141 findgroup(name)
    142 	register char name[];
    143 {
    144 	register struct grouphead *gh;
    145 
    146 	for (gh = groups[hash(name)]; gh != NOGRP; gh = gh->g_link)
    147 		if (*gh->g_name == *name && equal(gh->g_name, name))
    148 			return(gh);
    149 	return(NOGRP);
    150 }
    151 
    152 /*
    153  * Print a group out on stdout
    154  */
    155 
    156 printgroup(name)
    157 	char name[];
    158 {
    159 	register struct grouphead *gh;
    160 	register struct group *gp;
    161 
    162 	if ((gh = findgroup(name)) == NOGRP) {
    163 		printf("\"%s\": not a group\n", name);
    164 		return;
    165 	}
    166 	printf("%s\t", gh->g_name);
    167 	for (gp = gh->g_list; gp != NOGE; gp = gp->ge_link)
    168 		printf(" %s", gp->ge_name);
    169 	putchar('\n');
    170 }
    171 
    172 /*
    173  * Hash the passed string and return an index into
    174  * the variable or group hash table.
    175  */
    176 
    177 hash(name)
    178 	register char *name;
    179 {
    180 	register h = 0;
    181 
    182 	while (*name) {
    183 		h <<= 2;
    184 		h += *name++;
    185 	}
    186 	if (h < 0 && (h = -h) < 0)
    187 		h = 0;
    188 	return (h % HSHSIZE);
    189 }
    190