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1#include "util.h"
2#include "string.h"
3#include "strfilter.h"
4
5/* Operators */
6static const char *OP_and = "&"; /* Logical AND */
7static const char *OP_or = "|"; /* Logical OR */
8static const char *OP_not = "!"; /* Logical NOT */
9
10#define is_operator(c) ((c) == '|' || (c) == '&' || (c) == '!')
11#define is_separator(c) (is_operator(c) || (c) == '(' || (c) == ')')
12
13static void strfilter_node__delete(struct strfilter_node *node)
14{
15 if (node) {
16 if (node->p && !is_operator(*node->p))
17 zfree((char **)&node->p);
18 strfilter_node__delete(node->l);
19 strfilter_node__delete(node->r);
20 free(node);
21 }
22}
23
24void strfilter__delete(struct strfilter *filter)
25{
26 if (filter) {
27 strfilter_node__delete(filter->root);
28 free(filter);
29 }
30}
31
32static const char *get_token(const char *s, const char **e)
33{
34 const char *p;
35
36 while (isspace(*s)) /* Skip spaces */
37 s++;
38
39 if (*s == '\0') {
40 p = s;
41 goto end;
42 }
43
44 p = s + 1;
45 if (!is_separator(*s)) {
46 /* End search */
47retry:
48 while (*p && !is_separator(*p) && !isspace(*p))
49 p++;
50 /* Escape and special case: '!' is also used in glob pattern */
51 if (*(p - 1) == '\\' || (*p == '!' && *(p - 1) == '[')) {
52 p++;
53 goto retry;
54 }
55 }
56end:
57 *e = p;
58 return s;
59}
60
61static struct strfilter_node *strfilter_node__alloc(const char *op,
62 struct strfilter_node *l,
63 struct strfilter_node *r)
64{
65 struct strfilter_node *node = zalloc(sizeof(*node));
66
67 if (node) {
68 node->p = op;
69 node->l = l;
70 node->r = r;
71 }
72
73 return node;
74}
75
76static struct strfilter_node *strfilter_node__new(const char *s,
77 const char **ep)
78{
79 struct strfilter_node root, *cur, *last_op;
80 const char *e;
81
82 if (!s)
83 return NULL;
84
85 memset(&root, 0, sizeof(root));
86 last_op = cur = &root;
87
88 s = get_token(s, &e);
89 while (*s != '\0' && *s != ')') {
90 switch (*s) {
91 case '&': /* Exchg last OP->r with AND */
92 if (!cur->r || !last_op->r)
93 goto error;
94 cur = strfilter_node__alloc(OP_and, last_op->r, NULL);
95 if (!cur)
96 goto nomem;
97 last_op->r = cur;
98 last_op = cur;
99 break;
100 case '|': /* Exchg the root with OR */
101 if (!cur->r || !root.r)
102 goto error;
103 cur = strfilter_node__alloc(OP_or, root.r, NULL);
104 if (!cur)
105 goto nomem;
106 root.r = cur;
107 last_op = cur;
108 break;
109 case '!': /* Add NOT as a leaf node */
110 if (cur->r)
111 goto error;
112 cur->r = strfilter_node__alloc(OP_not, NULL, NULL);
113 if (!cur->r)
114 goto nomem;
115 cur = cur->r;
116 break;
117 case '(': /* Recursively parses inside the parenthesis */
118 if (cur->r)
119 goto error;
120 cur->r = strfilter_node__new(s + 1, &s);
121 if (!s)
122 goto nomem;
123 if (!cur->r || *s != ')')
124 goto error;
125 e = s + 1;
126 break;
127 default:
128 if (cur->r)
129 goto error;
130 cur->r = strfilter_node__alloc(NULL, NULL, NULL);
131 if (!cur->r)
132 goto nomem;
133 cur->r->p = strndup(s, e - s);
134 if (!cur->r->p)
135 goto nomem;
136 }
137 s = get_token(e, &e);
138 }
139 if (!cur->r)
140 goto error;
141 *ep = s;
142 return root.r;
143nomem:
144 s = NULL;
145error:
146 *ep = s;
147 strfilter_node__delete(root.r);
148 return NULL;
149}
150
151/*
152 * Parse filter rule and return new strfilter.
153 * Return NULL if fail, and *ep == NULL if memory allocation failed.
154 */
155struct strfilter *strfilter__new(const char *rules, const char **err)
156{
157 struct strfilter *filter = zalloc(sizeof(*filter));
158 const char *ep = NULL;
159
160 if (filter)
161 filter->root = strfilter_node__new(rules, &ep);
162
163 if (!filter || !filter->root || *ep != '\0') {
164 if (err)
165 *err = ep;
166 strfilter__delete(filter);
167 filter = NULL;
168 }
169
170 return filter;
171}
172
173static int strfilter__append(struct strfilter *filter, bool _or,
174 const char *rules, const char **err)
175{
176 struct strfilter_node *right, *root;
177 const char *ep = NULL;
178
179 if (!filter || !rules)
180 return -EINVAL;
181
182 right = strfilter_node__new(rules, &ep);
183 if (!right || *ep != '\0') {
184 if (err)
185 *err = ep;
186 goto error;
187 }
188 root = strfilter_node__alloc(_or ? OP_or : OP_and, filter->root, right);
189 if (!root) {
190 ep = NULL;
191 goto error;
192 }
193
194 filter->root = root;
195 return 0;
196
197error:
198 strfilter_node__delete(right);
199 return ep ? -EINVAL : -ENOMEM;
200}
201
202int strfilter__or(struct strfilter *filter, const char *rules, const char **err)
203{
204 return strfilter__append(filter, true, rules, err);
205}
206
207int strfilter__and(struct strfilter *filter, const char *rules,
208 const char **err)
209{
210 return strfilter__append(filter, false, rules, err);
211}
212
213static bool strfilter_node__compare(struct strfilter_node *node,
214 const char *str)
215{
216 if (!node || !node->p)
217 return false;
218
219 switch (*node->p) {
220 case '|': /* OR */
221 return strfilter_node__compare(node->l, str) ||
222 strfilter_node__compare(node->r, str);
223 case '&': /* AND */
224 return strfilter_node__compare(node->l, str) &&
225 strfilter_node__compare(node->r, str);
226 case '!': /* NOT */
227 return !strfilter_node__compare(node->r, str);
228 default:
229 return strglobmatch(str, node->p);
230 }
231}
232
233/* Return true if STR matches the filter rules */
234bool strfilter__compare(struct strfilter *filter, const char *str)
235{
236 if (!filter)
237 return false;
238 return strfilter_node__compare(filter->root, str);
239}
240
241static int strfilter_node__sprint(struct strfilter_node *node, char *buf);
242
243/* sprint node in parenthesis if needed */
244static int strfilter_node__sprint_pt(struct strfilter_node *node, char *buf)
245{
246 int len;
247 int pt = node->r ? 2 : 0; /* don't need to check node->l */
248
249 if (buf && pt)
250 *buf++ = '(';
251 len = strfilter_node__sprint(node, buf);
252 if (len < 0)
253 return len;
254 if (buf && pt)
255 *(buf + len) = ')';
256 return len + pt;
257}
258
259static int strfilter_node__sprint(struct strfilter_node *node, char *buf)
260{
261 int len = 0, rlen;
262
263 if (!node || !node->p)
264 return -EINVAL;
265
266 switch (*node->p) {
267 case '|':
268 case '&':
269 len = strfilter_node__sprint_pt(node->l, buf);
270 if (len < 0)
271 return len;
272 case '!':
273 if (buf) {
274 *(buf + len++) = *node->p;
275 buf += len;
276 } else
277 len++;
278 rlen = strfilter_node__sprint_pt(node->r, buf);
279 if (rlen < 0)
280 return rlen;
281 len += rlen;
282 break;
283 default:
284 len = strlen(node->p);
285 if (buf)
286 strcpy(buf, node->p);
287 }
288
289 return len;
290}
291
292char *strfilter__string(struct strfilter *filter)
293{
294 int len;
295 char *ret = NULL;
296
297 len = strfilter_node__sprint(filter->root, NULL);
298 if (len < 0)
299 return NULL;
300
301 ret = malloc(len + 1);
302 if (ret)
303 strfilter_node__sprint(filter->root, ret);
304
305 return ret;
306}
1#include "util.h"
2#include "string.h"
3#include "strfilter.h"
4
5/* Operators */
6static const char *OP_and = "&"; /* Logical AND */
7static const char *OP_or = "|"; /* Logical OR */
8static const char *OP_not = "!"; /* Logical NOT */
9
10#define is_operator(c) ((c) == '|' || (c) == '&' || (c) == '!')
11#define is_separator(c) (is_operator(c) || (c) == '(' || (c) == ')')
12
13static void strfilter_node__delete(struct strfilter_node *node)
14{
15 if (node) {
16 if (node->p && !is_operator(*node->p))
17 zfree((char **)&node->p);
18 strfilter_node__delete(node->l);
19 strfilter_node__delete(node->r);
20 free(node);
21 }
22}
23
24void strfilter__delete(struct strfilter *filter)
25{
26 if (filter) {
27 strfilter_node__delete(filter->root);
28 free(filter);
29 }
30}
31
32static const char *get_token(const char *s, const char **e)
33{
34 const char *p;
35
36 while (isspace(*s)) /* Skip spaces */
37 s++;
38
39 if (*s == '\0') {
40 p = s;
41 goto end;
42 }
43
44 p = s + 1;
45 if (!is_separator(*s)) {
46 /* End search */
47retry:
48 while (*p && !is_separator(*p) && !isspace(*p))
49 p++;
50 /* Escape and special case: '!' is also used in glob pattern */
51 if (*(p - 1) == '\\' || (*p == '!' && *(p - 1) == '[')) {
52 p++;
53 goto retry;
54 }
55 }
56end:
57 *e = p;
58 return s;
59}
60
61static struct strfilter_node *strfilter_node__alloc(const char *op,
62 struct strfilter_node *l,
63 struct strfilter_node *r)
64{
65 struct strfilter_node *node = zalloc(sizeof(*node));
66
67 if (node) {
68 node->p = op;
69 node->l = l;
70 node->r = r;
71 }
72
73 return node;
74}
75
76static struct strfilter_node *strfilter_node__new(const char *s,
77 const char **ep)
78{
79 struct strfilter_node root, *cur, *last_op;
80 const char *e;
81
82 if (!s)
83 return NULL;
84
85 memset(&root, 0, sizeof(root));
86 last_op = cur = &root;
87
88 s = get_token(s, &e);
89 while (*s != '\0' && *s != ')') {
90 switch (*s) {
91 case '&': /* Exchg last OP->r with AND */
92 if (!cur->r || !last_op->r)
93 goto error;
94 cur = strfilter_node__alloc(OP_and, last_op->r, NULL);
95 if (!cur)
96 goto nomem;
97 last_op->r = cur;
98 last_op = cur;
99 break;
100 case '|': /* Exchg the root with OR */
101 if (!cur->r || !root.r)
102 goto error;
103 cur = strfilter_node__alloc(OP_or, root.r, NULL);
104 if (!cur)
105 goto nomem;
106 root.r = cur;
107 last_op = cur;
108 break;
109 case '!': /* Add NOT as a leaf node */
110 if (cur->r)
111 goto error;
112 cur->r = strfilter_node__alloc(OP_not, NULL, NULL);
113 if (!cur->r)
114 goto nomem;
115 cur = cur->r;
116 break;
117 case '(': /* Recursively parses inside the parenthesis */
118 if (cur->r)
119 goto error;
120 cur->r = strfilter_node__new(s + 1, &s);
121 if (!s)
122 goto nomem;
123 if (!cur->r || *s != ')')
124 goto error;
125 e = s + 1;
126 break;
127 default:
128 if (cur->r)
129 goto error;
130 cur->r = strfilter_node__alloc(NULL, NULL, NULL);
131 if (!cur->r)
132 goto nomem;
133 cur->r->p = strndup(s, e - s);
134 if (!cur->r->p)
135 goto nomem;
136 }
137 s = get_token(e, &e);
138 }
139 if (!cur->r)
140 goto error;
141 *ep = s;
142 return root.r;
143nomem:
144 s = NULL;
145error:
146 *ep = s;
147 strfilter_node__delete(root.r);
148 return NULL;
149}
150
151/*
152 * Parse filter rule and return new strfilter.
153 * Return NULL if fail, and *ep == NULL if memory allocation failed.
154 */
155struct strfilter *strfilter__new(const char *rules, const char **err)
156{
157 struct strfilter *filter = zalloc(sizeof(*filter));
158 const char *ep = NULL;
159
160 if (filter)
161 filter->root = strfilter_node__new(rules, &ep);
162
163 if (!filter || !filter->root || *ep != '\0') {
164 if (err)
165 *err = ep;
166 strfilter__delete(filter);
167 filter = NULL;
168 }
169
170 return filter;
171}
172
173static bool strfilter_node__compare(struct strfilter_node *node,
174 const char *str)
175{
176 if (!node || !node->p)
177 return false;
178
179 switch (*node->p) {
180 case '|': /* OR */
181 return strfilter_node__compare(node->l, str) ||
182 strfilter_node__compare(node->r, str);
183 case '&': /* AND */
184 return strfilter_node__compare(node->l, str) &&
185 strfilter_node__compare(node->r, str);
186 case '!': /* NOT */
187 return !strfilter_node__compare(node->r, str);
188 default:
189 return strglobmatch(str, node->p);
190 }
191}
192
193/* Return true if STR matches the filter rules */
194bool strfilter__compare(struct strfilter *filter, const char *str)
195{
196 if (!filter)
197 return false;
198 return strfilter_node__compare(filter->root, str);
199}