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      1 /*	$NetBSD: vars.c,v 1.19 2023/09/08 14:22:04 shm Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1980, 1993
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  * 3. Neither the name of the University nor the names of its contributors
     16  *    may be used to endorse or promote products derived from this software
     17  *    without specific prior written permission.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     29  * SUCH DAMAGE.
     30  */
     31 
     32 #include <sys/cdefs.h>
     33 #ifndef lint
     34 #if 0
     35 static char sccsid[] = "@(#)vars.c	8.1 (Berkeley) 6/6/93";
     36 #else
     37 __RCSID("$NetBSD: vars.c,v 1.19 2023/09/08 14:22:04 shm Exp $");
     38 #endif
     39 #endif /* not lint */
     40 
     41 #include "rcv.h"
     42 #include <util.h>
     43 
     44 #include "extern.h"
     45 
     46 /*
     47  * Mail -- a mail program
     48  *
     49  * Variable handling stuff.
     50  */
     51 
     52 /*
     53  * Free up a variable string.  We do not bother to allocate
     54  * strings whose value is "" since they are expected to be frequent.
     55  * Thus, we cannot free same!
     56  */
     57 PUBLIC void
     58 v_free(char *cp)
     59 {
     60 	if (*cp)
     61 		free(cp);
     62 }
     63 
     64 /*
     65  * Copy a variable value into permanent (ie, not collected after each
     66  * command) space.  Do not bother to alloc space for ""
     67  */
     68 PUBLIC char *
     69 vcopy(const char str[])
     70 {
     71 	char *new;
     72 	size_t len;
     73 
     74 	if (*str == '\0')
     75 		return estrdup("");
     76 	len = strlen(str) + 1;
     77 	new = emalloc(len);
     78 	(void)memmove(new, str, len);
     79 	return new;
     80 }
     81 
     82 /*
     83  * Hash the passed string and return an index into
     84  * the variable or group hash table.
     85  */
     86 PUBLIC int
     87 hash(const char *name)
     88 {
     89 	unsigned int h = 0;
     90 
     91 	while (*name) {
     92 		h <<= 2;
     93 		h += *name++;
     94 	}
     95 	return h % HSHSIZE;
     96 }
     97 
     98 /*
     99  * Locate a variable and return its variable
    100  * node.
    101  */
    102 PUBLIC struct var *
    103 lookup(const char name[])
    104 {
    105 	struct var *vp;
    106 
    107 	for (vp = variables[hash(name)]; vp != NULL; vp = vp->v_link)
    108 		if (*vp->v_name == *name && equal(vp->v_name, name))
    109 			return vp;
    110 	return NULL;
    111 }
    112 
    113 /*
    114  * Assign a value to a variable.
    115  */
    116 PUBLIC void
    117 assign(const char name[], const char values[])
    118 {
    119 	struct var *vp;
    120 	int h;
    121 
    122 	h = hash(name);
    123 	vp = lookup(name);
    124 	if (vp == NULL) {
    125 		vp = ecalloc(1, sizeof(*vp));
    126 		vp->v_name = vcopy(name);
    127 		vp->v_link = variables[h];
    128 		variables[h] = vp;
    129 	}
    130 	else
    131                 v_free(vp->v_value);
    132 	vp->v_value = vcopy(values);
    133 }
    134 
    135 /*
    136  * Get the value of a variable and return it.
    137  * Look in the environment if its not available locally.
    138  */
    139 PUBLIC char *
    140 value(const char name[])
    141 {
    142 	struct var *vp;
    143 
    144 	if ((vp = lookup(name)) == NULL)
    145 		return getenv(name);
    146 	return vp->v_value;
    147 }
    148 
    149 /*
    150  * Locate a group name and return it.
    151  */
    152 PUBLIC struct grouphead *
    153 findgroup(const char name[])
    154 {
    155 	struct grouphead *gh;
    156 
    157 	for (gh = groups[hash(name)]; gh != NULL; gh = gh->g_link)
    158 		if (*gh->g_name == *name && equal(gh->g_name, name))
    159 			return gh;
    160 	return NULL;
    161 }
    162 
    163 /*
    164  * Print a group out on stdout
    165  */
    166 PUBLIC void
    167 printgroup(const char name[])
    168 {
    169 	struct grouphead *gh;
    170 	struct group *gp;
    171 
    172 	if ((gh = findgroup(name)) == NULL) {
    173 		(void)printf("\"%s\": not a group\n", name);
    174 		return;
    175 	}
    176 	(void)printf("%s\t", gh->g_name);
    177 	for (gp = gh->g_list; gp != NULL; gp = gp->ge_link)
    178 		(void)printf(" %s", gp->ge_name);
    179 	(void)putchar('\n');
    180 }
    181