filter.c revision 391318fb9b1f0f0f67b642309f5c9e94557f8568 
1/*
2 * This file is part of ltrace.
3 * Copyright (C) 2012 Petr Machata, Red Hat Inc.
4 *
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU General Public License as
7 * published by the Free Software Foundation; either version 2 of the
8 * License, or (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful, but
11 * WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13 * General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
18 * 02110-1301 USA
19 */
20
21#include <stdlib.h>
22#include <error.h>
23#include <assert.h>
24
25#include "filter.h"
26#include "library.h"
27
28void
29filter_init(struct filter *filt)
30{
31	filt->rules = NULL;
32	filt->next = NULL;
33}
34
35void
36filter_destroy(struct filter *filt)
37{
38	struct filter_rule *it;
39	for (it = filt->rules; it != NULL; ) {
40		struct filter_rule *next = it->next;
41		filter_rule_destroy(it);
42		it = next;
43	}
44}
45
46void
47filter_rule_init(struct filter_rule *rule, enum filter_rule_type type,
48		 struct filter_lib_matcher *matcher,
49		 regex_t symbol_re)
50{
51	rule->type = type;
52	rule->lib_matcher = matcher;
53	rule->symbol_re = symbol_re;
54	rule->next = NULL;
55}
56
57void
58filter_rule_destroy(struct filter_rule *rule)
59{
60	filter_lib_matcher_destroy(rule->lib_matcher);
61	regfree(&rule->symbol_re);
62}
63
64void
65filter_add_rule(struct filter *filt, struct filter_rule *rule)
66{
67	rule->next = filt->rules;
68	filt->rules = rule;
69}
70
71void
72filter_lib_matcher_name_init(struct filter_lib_matcher *matcher,
73			     enum filter_lib_matcher_type type,
74			     regex_t libname_re)
75{
76	switch (type) {
77	case FLM_MAIN:
78		assert(type != type);
79		abort();
80
81	case FLM_SONAME:
82	case FLM_PATHNAME:
83		matcher->type = type;
84		matcher->libname_re = libname_re;
85	}
86}
87
88void
89filter_lib_matcher_main_init(struct filter_lib_matcher *matcher)
90{
91	matcher->type = FLM_MAIN;
92}
93
94void
95filter_lib_matcher_destroy(struct filter_lib_matcher *matcher)
96{
97	switch (matcher->type) {
98	case FLM_SONAME:
99	case FLM_PATHNAME:
100		regfree(&matcher->libname_re);
101		break;
102	case FLM_MAIN:
103		break;
104	}
105}
106
107static int
108re_match_or_error(regex_t *re, const char *name, const char *what)
109{
110	int status = regexec(re, name, 0, NULL, 0);
111	if (status == 0)
112		return 1;
113	if (status == REG_NOMATCH)
114		return 0;
115
116	char buf[200];
117	regerror(status, re, buf, sizeof buf);
118	error(0, 0, "Error when matching %s: %s", name, buf);
119
120	return 0;
121}
122
123static int
124matcher_matches_library(struct filter_lib_matcher *matcher, struct library *lib)
125{
126	switch (matcher->type) {
127	case FLM_SONAME:
128		return re_match_or_error(&matcher->libname_re, lib->soname,
129					 "library soname");
130	case FLM_PATHNAME:
131		return re_match_or_error(&matcher->libname_re, lib->pathname,
132					 "library pathname");
133	case FLM_MAIN:
134		return lib->type == LT_LIBTYPE_MAIN;
135	}
136	assert(matcher->type != matcher->type);
137	abort();
138}
139
140int
141filter_matches_library(struct filter *filt, struct library *lib)
142{
143	if (filt == NULL)
144		return 0;
145
146	struct filter_rule *it;
147	for (it = filt->rules; it != NULL; it = it->next)
148		switch (it->type) {
149		case FR_ADD:
150			if (matcher_matches_library(it->lib_matcher, lib))
151				return 1;
152		case FR_SUBTRACT:
153			continue;
154		};
155	return 0;
156}
157
158int
159filter_matches_symbol(struct filter *filt,
160		      const char *sym_name, struct library *lib)
161{
162	int matches = 0;
163	for (; filt != NULL; filt = filt->next) {
164		struct filter_rule *it;
165		for (it = filt->rules; it != NULL; it = it->next) {
166			switch (it->type) {
167			case FR_ADD:
168				if (matches)
169					continue;
170				break;
171			case FR_SUBTRACT:
172				if (!matches)
173					continue;
174			}
175
176			if (matcher_matches_library(it->lib_matcher, lib)
177			    && re_match_or_error(&it->symbol_re, sym_name,
178						 "symbol name"))
179				matches = !matches;
180		}
181	}
182	return matches;
183}
184