| 1 | /* |
| 2 | * Copyright (C) 2017 Philippe Proulx <pproulx@efficios.com> |
| 3 | * |
| 4 | * This library is free software; you can redistribute it and/or |
| 5 | * modify it under the terms of the GNU Lesser General Public |
| 6 | * License as published by the Free Software Foundation; only |
| 7 | * version 2.1 of the License. |
| 8 | * |
| 9 | * This library is distributed in the hope that it will be useful, |
| 10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 12 | * Lesser General Public License for more details. |
| 13 | * |
| 14 | * You should have received a copy of the GNU Lesser General Public |
| 15 | * License along with this library; if not, write to the Free Software |
| 16 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| 17 | */ |
| 18 | |
| 19 | #include <linux/types.h> |
| 20 | |
| 21 | #include <lttng-string-utils.h> |
| 22 | |
| 23 | enum star_glob_pattern_type_flags { |
| 24 | STAR_GLOB_PATTERN_TYPE_FLAG_NONE = 0, |
| 25 | STAR_GLOB_PATTERN_TYPE_FLAG_PATTERN = (1U << 0), |
| 26 | STAR_GLOB_PATTERN_TYPE_FLAG_END_ONLY = (1U << 1), |
| 27 | }; |
| 28 | |
| 29 | static |
| 30 | enum star_glob_pattern_type_flags strutils_test_glob_pattern(const char *pattern) |
| 31 | { |
| 32 | enum star_glob_pattern_type_flags ret = |
| 33 | STAR_GLOB_PATTERN_TYPE_FLAG_NONE; |
| 34 | const char *p; |
| 35 | |
| 36 | for (p = pattern; *p != '\0'; p++) { |
| 37 | switch (*p) { |
| 38 | case '*': |
| 39 | ret = STAR_GLOB_PATTERN_TYPE_FLAG_PATTERN; |
| 40 | |
| 41 | if (p[1] == '\0') { |
| 42 | ret |= STAR_GLOB_PATTERN_TYPE_FLAG_END_ONLY; |
| 43 | } |
| 44 | goto end; |
| 45 | case '\\': |
| 46 | p++; |
| 47 | |
| 48 | if (*p == '\0') { |
| 49 | goto end; |
| 50 | } |
| 51 | break; |
| 52 | default: |
| 53 | break; |
| 54 | } |
| 55 | } |
| 56 | |
| 57 | end: |
| 58 | return ret; |
| 59 | } |
| 60 | |
| 61 | /* |
| 62 | * Returns true if `pattern` is a star-only globbing pattern, that is, |
| 63 | * it contains at least one non-escaped `*`. |
| 64 | */ |
| 65 | bool strutils_is_star_glob_pattern(const char *pattern) |
| 66 | { |
| 67 | return strutils_test_glob_pattern(pattern) & |
| 68 | STAR_GLOB_PATTERN_TYPE_FLAG_PATTERN; |
| 69 | } |
| 70 | |
| 71 | /* |
| 72 | * Returns true if `pattern` is a globbing pattern with a globbing, |
| 73 | * non-escaped star only at its very end. |
| 74 | */ |
| 75 | bool strutils_is_star_at_the_end_only_glob_pattern(const char *pattern) |
| 76 | { |
| 77 | return strutils_test_glob_pattern(pattern) & |
| 78 | STAR_GLOB_PATTERN_TYPE_FLAG_END_ONLY; |
| 79 | } |
| 80 | |
| 81 | struct string_with_len { |
| 82 | const char *str; |
| 83 | size_t len; |
| 84 | }; |
| 85 | |
| 86 | static |
| 87 | char string_get_char_at_cb(size_t at, void *data) |
| 88 | { |
| 89 | struct string_with_len *string_with_len = data; |
| 90 | |
| 91 | if (at >= string_with_len->len) { |
| 92 | return '\0'; |
| 93 | } |
| 94 | |
| 95 | return string_with_len->str[at]; |
| 96 | } |
| 97 | |
| 98 | /* |
| 99 | * Globbing matching function with the star feature only (`?` and |
| 100 | * character sets are not supported). This matches `candidate` (plain |
| 101 | * string) against `pattern`. A literal star can be escaped with `\` in |
| 102 | * `pattern`. |
| 103 | * |
| 104 | * `pattern_len` or `candidate_len` can be greater than the actual |
| 105 | * string length of `pattern` or `candidate` if the string is |
| 106 | * null-terminated. |
| 107 | */ |
| 108 | bool strutils_star_glob_match(const char *pattern, size_t pattern_len, |
| 109 | const char *candidate, size_t candidate_len) { |
| 110 | struct string_with_len pattern_with_len = { |
| 111 | pattern, pattern_len |
| 112 | }; |
| 113 | struct string_with_len candidate_with_len = { |
| 114 | candidate, candidate_len |
| 115 | }; |
| 116 | |
| 117 | return strutils_star_glob_match_char_cb(string_get_char_at_cb, |
| 118 | &pattern_with_len, string_get_char_at_cb, |
| 119 | &candidate_with_len); |
| 120 | } |
| 121 | |
| 122 | bool strutils_star_glob_match_char_cb( |
| 123 | strutils_get_char_at_cb pattern_get_char_at_cb, |
| 124 | void *pattern_get_char_at_cb_data, |
| 125 | strutils_get_char_at_cb candidate_get_char_at_cb, |
| 126 | void *candidate_get_char_at_cb_data) |
| 127 | { |
| 128 | size_t retry_p_at = 0, retry_c_at = 0, c_at, p_at; |
| 129 | char c, p, prev_p; |
| 130 | bool got_a_star = false; |
| 131 | |
| 132 | retry: |
| 133 | c_at = retry_c_at; |
| 134 | c = candidate_get_char_at_cb(c_at, candidate_get_char_at_cb_data); |
| 135 | p_at = retry_p_at; |
| 136 | p = pattern_get_char_at_cb(p_at, pattern_get_char_at_cb_data); |
| 137 | |
| 138 | /* |
| 139 | * The concept here is to retry a match in the specific case |
| 140 | * where we already got a star. The retry position for the |
| 141 | * pattern is just after the most recent star, and the retry |
| 142 | * position for the candidate is the character following the |
| 143 | * last try's first character. |
| 144 | * |
| 145 | * Example: |
| 146 | * |
| 147 | * candidate: hi ev every onyx one |
| 148 | * ^ |
| 149 | * pattern: hi*every*one |
| 150 | * ^ |
| 151 | * |
| 152 | * candidate: hi ev every onyx one |
| 153 | * ^ |
| 154 | * pattern: hi*every*one |
| 155 | * ^ |
| 156 | * |
| 157 | * candidate: hi ev every onyx one |
| 158 | * ^ |
| 159 | * pattern: hi*every*one |
| 160 | * ^ |
| 161 | * |
| 162 | * candidate: hi ev every onyx one |
| 163 | * ^ |
| 164 | * pattern: hi*every*one |
| 165 | * ^ MISMATCH |
| 166 | * |
| 167 | * candidate: hi ev every onyx one |
| 168 | * ^ |
| 169 | * pattern: hi*every*one |
| 170 | * ^ |
| 171 | * |
| 172 | * candidate: hi ev every onyx one |
| 173 | * ^^ |
| 174 | * pattern: hi*every*one |
| 175 | * ^^ |
| 176 | * |
| 177 | * candidate: hi ev every onyx one |
| 178 | * ^ ^ |
| 179 | * pattern: hi*every*one |
| 180 | * ^ ^ MISMATCH |
| 181 | * |
| 182 | * candidate: hi ev every onyx one |
| 183 | * ^ |
| 184 | * pattern: hi*every*one |
| 185 | * ^ MISMATCH |
| 186 | * |
| 187 | * candidate: hi ev every onyx one |
| 188 | * ^ |
| 189 | * pattern: hi*every*one |
| 190 | * ^ MISMATCH |
| 191 | * |
| 192 | * candidate: hi ev every onyx one |
| 193 | * ^ |
| 194 | * pattern: hi*every*one |
| 195 | * ^ |
| 196 | * |
| 197 | * candidate: hi ev every onyx one |
| 198 | * ^^ |
| 199 | * pattern: hi*every*one |
| 200 | * ^^ |
| 201 | * |
| 202 | * candidate: hi ev every onyx one |
| 203 | * ^ ^ |
| 204 | * pattern: hi*every*one |
| 205 | * ^ ^ |
| 206 | * |
| 207 | * candidate: hi ev every onyx one |
| 208 | * ^ ^ |
| 209 | * pattern: hi*every*one |
| 210 | * ^ ^ |
| 211 | * |
| 212 | * candidate: hi ev every onyx one |
| 213 | * ^ ^ |
| 214 | * pattern: hi*every*one |
| 215 | * ^ ^ |
| 216 | * |
| 217 | * candidate: hi ev every onyx one |
| 218 | * ^ |
| 219 | * pattern: hi*every*one |
| 220 | * ^ |
| 221 | * |
| 222 | * candidate: hi ev every onyx one |
| 223 | * ^ |
| 224 | * pattern: hi*every*one |
| 225 | * ^ MISMATCH |
| 226 | * |
| 227 | * candidate: hi ev every onyx one |
| 228 | * ^ |
| 229 | * pattern: hi*every*one |
| 230 | * ^ |
| 231 | * |
| 232 | * candidate: hi ev every onyx one |
| 233 | * ^^ |
| 234 | * pattern: hi*every*one |
| 235 | * ^^ |
| 236 | * |
| 237 | * candidate: hi ev every onyx one |
| 238 | * ^ ^ |
| 239 | * pattern: hi*every*one |
| 240 | * ^ ^ MISMATCH |
| 241 | * |
| 242 | * candidate: hi ev every onyx one |
| 243 | * ^ |
| 244 | * pattern: hi*every*one |
| 245 | * ^ MISMATCH |
| 246 | * |
| 247 | * candidate: hi ev every onyx one |
| 248 | * ^ |
| 249 | * pattern: hi*every*one |
| 250 | * ^ MISMATCH |
| 251 | * |
| 252 | * candidate: hi ev every onyx one |
| 253 | * ^ |
| 254 | * pattern: hi*every*one |
| 255 | * ^ MISMATCH |
| 256 | * |
| 257 | * candidate: hi ev every onyx one |
| 258 | * ^ |
| 259 | * pattern: hi*every*one |
| 260 | * ^ MISMATCH |
| 261 | * |
| 262 | * candidate: hi ev every onyx one |
| 263 | * ^ |
| 264 | * pattern: hi*every*one |
| 265 | * ^ |
| 266 | * |
| 267 | * candidate: hi ev every onyx one |
| 268 | * ^^ |
| 269 | * pattern: hi*every*one |
| 270 | * ^^ |
| 271 | * |
| 272 | * candidate: hi ev every onyx one |
| 273 | * ^ ^ |
| 274 | * pattern: hi*every*one |
| 275 | * ^ ^ |
| 276 | * |
| 277 | * candidate: hi ev every onyx one |
| 278 | * ^ ^ |
| 279 | * pattern: hi*every*one |
| 280 | * ^ ^ SUCCESS |
| 281 | */ |
| 282 | while (c != '\0') { |
| 283 | if (p == '\0') { |
| 284 | goto end_of_pattern; |
| 285 | } |
| 286 | |
| 287 | switch (p) { |
| 288 | case '*': |
| 289 | { |
| 290 | char retry_p; |
| 291 | got_a_star = true; |
| 292 | |
| 293 | /* |
| 294 | * Our first try starts at the current candidate |
| 295 | * character and after the star in the pattern. |
| 296 | */ |
| 297 | retry_c_at = c_at; |
| 298 | retry_p_at = p_at + 1; |
| 299 | retry_p = pattern_get_char_at_cb(retry_p_at, |
| 300 | pattern_get_char_at_cb_data); |
| 301 | |
| 302 | if (retry_p == '\0') { |
| 303 | /* |
| 304 | * Star at the end of the pattern at |
| 305 | * this point: automatic match. |
| 306 | */ |
| 307 | return true; |
| 308 | } |
| 309 | |
| 310 | goto retry; |
| 311 | } |
| 312 | case '\\': |
| 313 | /* Go to escaped character. */ |
| 314 | p_at++; |
| 315 | p = pattern_get_char_at_cb(p_at, |
| 316 | pattern_get_char_at_cb_data); |
| 317 | |
| 318 | /* |
| 319 | * Fall through the default case which will |
| 320 | * compare the escaped character now. |
| 321 | */ |
| 322 | default: |
| 323 | if (p == '\0' || c != p) { |
| 324 | end_of_pattern: |
| 325 | /* Character mismatch OR end of pattern. */ |
| 326 | if (!got_a_star) { |
| 327 | /* |
| 328 | * We didn't get any star yet, |
| 329 | * so this first mismatch |
| 330 | * automatically makes the whole |
| 331 | * test fail. |
| 332 | */ |
| 333 | return false; |
| 334 | } |
| 335 | |
| 336 | /* |
| 337 | * Next try: next candidate character, |
| 338 | * original pattern character (following |
| 339 | * the most recent star). |
| 340 | */ |
| 341 | retry_c_at++; |
| 342 | goto retry; |
| 343 | } |
| 344 | break; |
| 345 | } |
| 346 | |
| 347 | /* Next pattern and candidate characters. */ |
| 348 | c_at++; |
| 349 | c = candidate_get_char_at_cb(c_at, |
| 350 | candidate_get_char_at_cb_data); |
| 351 | p_at++; |
| 352 | p = pattern_get_char_at_cb(p_at, pattern_get_char_at_cb_data); |
| 353 | } |
| 354 | |
| 355 | /* |
| 356 | * We checked every candidate character and we're still in a |
| 357 | * success state: the only pattern character allowed to remain |
| 358 | * is a star. |
| 359 | */ |
| 360 | if (p == '\0') { |
| 361 | return true; |
| 362 | } |
| 363 | |
| 364 | prev_p = p; |
| 365 | p_at++; |
| 366 | p = pattern_get_char_at_cb(p_at, pattern_get_char_at_cb_data); |
| 367 | return prev_p == '*' && p == '\0'; |
| 368 | } |