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vars.c revision 1.18 
      1 /*	$NetBSD: vars.c,v 1.18 2007/10/27 15:14:51 christos 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 1.18 2007/10/27 15:14:51 christos 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 	int h = 0;
     90 
     91 	while (*name) {
     92 		h <<= 2;
     93 		h += *name++;
     94 	}
     95 	if (h < 0 && (h = -h) < 0)
     96 		h = 0;
     97 	return h % HSHSIZE;
     98 }
     99 
    100 /*
    101  * Locate a variable and return its variable
    102  * node.
    103  */
    104 PUBLIC struct var *
    105 lookup(const char name[])
    106 {
    107 	struct var *vp;
    108 
    109 	for (vp = variables[hash(name)]; vp != NULL; vp = vp->v_link)
    110 		if (*vp->v_name == *name && equal(vp->v_name, name))
    111 			return vp;
    112 	return NULL;
    113 }
    114 
    115 /*
    116  * Assign a value to a variable.
    117  */
    118 PUBLIC void
    119 assign(const char name[], const char values[])
    120 {
    121 	struct var *vp;
    122 	int h;
    123 
    124 	h = hash(name);
    125 	vp = lookup(name);
    126 	if (vp == NULL) {
    127 		vp = ecalloc(1, sizeof(*vp));
    128 		vp->v_name = vcopy(name);
    129 		vp->v_link = variables[h];
    130 		variables[h] = vp;
    131 	}
    132 	else
    133                 v_free(vp->v_value);
    134 	vp->v_value = vcopy(values);
    135 }
    136 
    137 /*
    138  * Get the value of a variable and return it.
    139  * Look in the environment if its not available locally.
    140  */
    141 PUBLIC char *
    142 value(const char name[])
    143 {
    144 	struct var *vp;
    145 
    146 	if ((vp = lookup(name)) == NULL)
    147 		return getenv(name);
    148 	return vp->v_value;
    149 }
    150 
    151 /*
    152  * Locate a group name and return it.
    153  */
    154 PUBLIC struct grouphead *
    155 findgroup(const char name[])
    156 {
    157 	struct grouphead *gh;
    158 
    159 	for (gh = groups[hash(name)]; gh != NULL; gh = gh->g_link)
    160 		if (*gh->g_name == *name && equal(gh->g_name, name))
    161 			return gh;
    162 	return NULL;
    163 }
    164 
    165 /*
    166  * Print a group out on stdout
    167  */
    168 PUBLIC void
    169 printgroup(const char name[])
    170 {
    171 	struct grouphead *gh;
    172 	struct group *gp;
    173 
    174 	if ((gh = findgroup(name)) == NULL) {
    175 		(void)printf("\"%s\": not a group\n", name);
    176 		return;
    177 	}
    178 	(void)printf("%s\t", gh->g_name);
    179 	for (gp = gh->g_list; gp != NULL; gp = gp->ge_link)
    180 		(void)printf(" %s", gp->ge_name);
    181 	(void)putchar('\n');
    182 }
    183