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vars.c revision 1.13 
      1 /*	$NetBSD: vars.c,v 1.13 2005/07/19 01:38:38 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 1.13 2005/07/19 01:38:38 christos Exp $");
     38 #endif
     39 #endif /* not lint */
     40 
     41 #include "rcv.h"
     42 #include "extern.h"
     43 
     44 /*
     45  * Mail -- a mail program
     46  *
     47  * Variable handling stuff.
     48  */
     49 
     50 /*
     51  * Assign a value to a variable.
     52  */
     53 void
     54 assign(const char name[], const char values[])
     55 {
     56 	struct var *vp;
     57 	int h;
     58 
     59 	h = hash(name);
     60 	vp = lookup(name);
     61 	if (vp == NULL) {
     62 		vp = (struct var *) calloc(1, sizeof *vp);
     63 		if (vp == NULL)
     64 			errx(1, "Out of memory");
     65 		vp->v_name = vcopy(name);
     66 		vp->v_link = variables[h];
     67 		variables[h] = vp;
     68 	}
     69 	else
     70                 v_free(vp->v_value);
     71 	vp->v_value = vcopy(values);
     72 }
     73 
     74 /*
     75  * Free up a variable string.  We do not bother to allocate
     76  * strings whose value is "" since they are expected to be frequent.
     77  * Thus, we cannot free same!
     78  */
     79 void
     80 v_free(char *cp)
     81 {
     82 	if (*cp)
     83 		free(cp);
     84 }
     85 
     86 /*
     87  * Copy a variable value into permanent (ie, not collected after each
     88  * command) space.  Do not bother to alloc space for ""
     89  */
     90 
     91 char *
     92 vcopy(const char str[])
     93 {
     94 	char *new;
     95 	unsigned len;
     96 
     97 	if (*str == '\0')
     98 		return strdup("");
     99 	len = strlen(str) + 1;
    100 	if ((new = malloc(len)) == NULL)
    101 		errx(1, "Out of memory");
    102 	memmove(new, str, (int) len);
    103 	return new;
    104 }
    105 
    106 /*
    107  * Get the value of a variable and return it.
    108  * Look in the environment if its not available locally.
    109  */
    110 
    111 char *
    112 value(const char name[])
    113 {
    114 	struct var *vp;
    115 
    116 	if ((vp = lookup(name)) == NULL)
    117 		return(getenv(name));
    118 	return(vp->v_value);
    119 }
    120 
    121 /*
    122  * Locate a variable and return its variable
    123  * node.
    124  */
    125 
    126 struct var *
    127 lookup(const char name[])
    128 {
    129 	struct var *vp;
    130 
    131 	for (vp = variables[hash(name)]; vp != NULL; vp = vp->v_link)
    132 		if (*vp->v_name == *name && equal(vp->v_name, name))
    133 			return(vp);
    134 	return(NULL);
    135 }
    136 
    137 /*
    138  * Locate a group name and return it.
    139  */
    140 
    141 struct grouphead *
    142 findgroup(char name[])
    143 {
    144 	struct grouphead *gh;
    145 
    146 	for (gh = groups[hash(name)]; gh != NULL; gh = gh->g_link)
    147 		if (*gh->g_name == *name && equal(gh->g_name, name))
    148 			return(gh);
    149 	return(NULL);
    150 }
    151 
    152 /*
    153  * Print a group out on stdout
    154  */
    155 void
    156 printgroup(char name[])
    157 {
    158 	struct grouphead *gh;
    159 	struct group *gp;
    160 
    161 	if ((gh = findgroup(name)) == NULL) {
    162 		printf("\"%s\": not a group\n", name);
    163 		return;
    164 	}
    165 	printf("%s\t", gh->g_name);
    166 	for (gp = gh->g_list; gp != NULL; gp = gp->ge_link)
    167 		printf(" %s", gp->ge_name);
    168 	putchar('\n');
    169 }
    170 
    171 /*
    172  * Hash the passed string and return an index into
    173  * the variable or group hash table.
    174  */
    175 int
    176 hash(const char *name)
    177 {
    178 	int h = 0;
    179 
    180 	while (*name) {
    181 		h <<= 2;
    182 		h += *name++;
    183 	}
    184 	if (h < 0 && (h = -h) < 0)
    185 		h = 0;
    186 	return (h % HSHSIZE);
    187 }
    188