1/*
2 * Copyright (c) 2008 Kungliga Tekniska Högskolan
3 * (Royal Institute of Technology, Stockholm, Sweden).
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 *
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 *
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 *
17 * 3. Neither the name of the Institute 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 INSTITUTE 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 INSTITUTE 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#include "hx_locl.h"
35
36struct hx_expr *
37_hx509_make_expr(enum hx_expr_op op, void *arg1, void *arg2)
38{
39    struct hx_expr *expr;
40
41    expr = malloc(sizeof(*expr));
42    if (expr == NULL)
43	return NULL;
44    expr->op = op;
45    expr->arg1 = arg1;
46    expr->arg2 = arg2;
47
48    return expr;
49}
50
51static const char *
52eval_word(hx509_context context, hx509_env env, struct hx_expr *word)
53{
54    switch (word->op) {
55    case expr_STRING:
56	return word->arg1;
57    case expr_VAR:
58	if (word->arg2 == NULL)
59	    return hx509_env_find(context, env, word->arg1);
60
61	env = hx509_env_find_binding(context, env, word->arg1);
62	if (env == NULL)
63	    return NULL;
64
65	return eval_word(context, env, word->arg2);
66    default:
67	return NULL;
68    }
69}
70
71static hx509_env
72find_variable(hx509_context context, hx509_env env, struct hx_expr *word)
73{
74    assert(word->op == expr_VAR);
75
76    if (word->arg2 == NULL)
77	return hx509_env_find_binding(context, env, word->arg1);
78
79    env = hx509_env_find_binding(context, env, word->arg1);
80    if (env == NULL)
81	return NULL;
82    return find_variable(context, env, word->arg2);
83}
84
85static int
86eval_comp(hx509_context context, hx509_env env, struct hx_expr *expr)
87{
88    switch (expr->op) {
89    case comp_NE:
90    case comp_EQ:
91    case comp_TAILEQ: {
92	const char *s1, *s2;
93	int ret;
94
95	s1 = eval_word(context, env, expr->arg1);
96	s2 = eval_word(context, env, expr->arg2);
97
98	if (s1 == NULL || s2 == NULL)
99	    return FALSE;
100
101	if (expr->op == comp_TAILEQ) {
102	    size_t len1 = strlen(s1);
103	    size_t len2 = strlen(s2);
104
105	    if (len1 < len2)
106		return 0;
107	    ret = strcmp(s1 + (len1 - len2), s2) == 0;
108	} else {
109	    ret = strcmp(s1, s2) == 0;
110	    if (expr->op == comp_NE)
111		ret = !ret;
112	}
113	return ret;
114    }
115    case comp_IN: {
116	struct hx_expr *subexpr;
117	const char *w, *s1;
118
119	w = eval_word(context, env, expr->arg1);
120
121	subexpr = expr->arg2;
122
123	if (subexpr->op == expr_WORDS) {
124	    while (subexpr) {
125		s1 = eval_word(context, env, subexpr->arg1);
126		if (strcmp(w, s1) == 0)
127		    return TRUE;
128		subexpr = subexpr->arg2;
129	    }
130	} else if (subexpr->op == expr_VAR) {
131	    hx509_env subenv;
132
133	    subenv = find_variable(context, env, subexpr);
134	    if (subenv == NULL)
135		return FALSE;
136
137	    while (subenv) {
138		if (subenv->type != env_string)
139		    continue;
140		if (strcmp(w, subenv->name) == 0)
141		    return TRUE;
142		if (strcmp(w, subenv->u.string) == 0)
143		    return TRUE;
144		subenv = subenv->next;
145	    }
146
147	} else
148	    _hx509_abort("hx509 eval IN unknown op: %d", (int)subexpr->op);
149
150	return FALSE;
151    }
152    default:
153	_hx509_abort("hx509 eval expr with unknown op: %d", (int)expr->op);
154    }
155    return FALSE;
156}
157
158int
159_hx509_expr_eval(hx509_context context, hx509_env env, struct hx_expr *expr)
160{
161    switch (expr->op) {
162    case op_TRUE:
163	return 1;
164    case op_FALSE:
165	return 0;
166    case op_NOT:
167	return ! _hx509_expr_eval(context, env, expr->arg1);
168    case op_AND:
169	return _hx509_expr_eval(context, env, expr->arg1) &&
170	    _hx509_expr_eval(context, env, expr->arg2);
171    case op_OR:
172	return _hx509_expr_eval(context, env, expr->arg1) ||
173	    _hx509_expr_eval(context, env, expr->arg2);
174    case op_COMP:
175	return eval_comp(context, env, expr->arg1);
176    default:
177	_hx509_abort("hx509 eval expr with unknown op: %d", (int)expr->op);
178	UNREACHABLE(return 0);
179    }
180}
181
182void
183_hx509_expr_free(struct hx_expr *expr)
184{
185    switch (expr->op) {
186    case expr_STRING:
187    case expr_NUMBER:
188	free(expr->arg1);
189	break;
190    case expr_WORDS:
191    case expr_FUNCTION:
192    case expr_VAR:
193	free(expr->arg1);
194	if (expr->arg2)
195	    _hx509_expr_free(expr->arg2);
196	break;
197    default:
198	if (expr->arg1)
199	    _hx509_expr_free(expr->arg1);
200	if (expr->arg2)
201	    _hx509_expr_free(expr->arg2);
202	break;
203    }
204    free(expr);
205}
206
207struct hx_expr *
208_hx509_expr_parse(const char *buf)
209{
210    _hx509_expr_input.buf = buf;
211    _hx509_expr_input.length = strlen(buf);
212    _hx509_expr_input.offset = 0;
213    _hx509_expr_input.expr = NULL;
214
215    if (_hx509_expr_input.error) {
216	free(_hx509_expr_input.error);
217	_hx509_expr_input.error = NULL;
218    }
219
220    yyparse();
221
222    return _hx509_expr_input.expr;
223}
224
225void
226_hx509_sel_yyerror (const char *s)
227{
228     if (_hx509_expr_input.error)
229         free(_hx509_expr_input.error);
230
231     _hx509_expr_input.error = strdup(s);
232}
233
234