Rev 2752 | Rev 2763 | Go to most recent revision | Show entire file | Ignore whitespace | Details | Blame | Last modification | View Log | RSS feed
Rev 2752 | Rev 2753 | ||
---|---|---|---|
Line 33... | Line 33... | ||
33 | /** |
33 | /** |
34 | * @file vfs_lookup.c |
34 | * @file vfs_lookup.c |
35 | * @brief |
35 | * @brief |
36 | */ |
36 | */ |
37 | 37 | ||
- | 38 | #include "vfs.h" |
|
38 | #include <ipc/ipc.h> |
39 | #include <ipc/ipc.h> |
39 | #include <async.h> |
40 | #include <async.h> |
40 | #include <errno.h> |
41 | #include <errno.h> |
41 | #include <string.h> |
42 | #include <string.h> |
42 | #include <stdlib.h> |
- | |
43 | #include <bool.h> |
43 | #include <bool.h> |
44 | #include <futex.h> |
44 | #include <futex.h> |
45 | #include <libadt/list.h> |
45 | #include <libadt/list.h> |
46 | #include <atomic.h> |
46 | #include <atomic.h> |
47 | #include "vfs.h" |
47 | #include <vfs/canonify.h> |
48 | 48 | ||
49 | #define min(a, b) ((a) < (b) ? (a) : (b)) |
49 | #define min(a, b) ((a) < (b) ? (a) : (b)) |
50 | 50 | ||
51 | /* Forward static declarations. */ |
- | |
52 | static char *canonify(char *path, size_t *lenp); |
- | |
53 | - | ||
54 | atomic_t plb_futex = FUTEX_INITIALIZER; |
51 | atomic_t plb_futex = FUTEX_INITIALIZER; |
55 | link_t plb_head; /**< PLB entry ring buffer. */ |
52 | link_t plb_head; /**< PLB entry ring buffer. */ |
56 | uint8_t *plb = NULL; |
53 | uint8_t *plb = NULL; |
57 | 54 | ||
58 | /** Perform a path lookup. |
55 | /** Perform a path lookup. |
Line 178... | Line 175... | ||
178 | } |
175 | } |
179 | 176 | ||
180 | return rc; |
177 | return rc; |
181 | } |
178 | } |
182 | 179 | ||
183 | /** Token types used for tokenization of path. */ |
- | |
184 | typedef enum { |
- | |
185 | TK_INVALID, |
- | |
186 | TK_SLASH, |
- | |
187 | TK_DOT, |
- | |
188 | TK_DOTDOT, |
- | |
189 | TK_COMP, |
- | |
190 | TK_NUL |
- | |
191 | } tokval_t; |
- | |
192 | - | ||
193 | typedef struct { |
- | |
194 | tokval_t kind; |
- | |
195 | char *start; |
- | |
196 | char *stop; |
- | |
197 | } token_t; |
- | |
198 | - | ||
199 | /** Fake up the TK_SLASH token. */ |
- | |
200 | static token_t slash_token(char *start) |
- | |
201 | { |
- | |
202 | token_t ret; |
- | |
203 | ret.kind = TK_SLASH; |
- | |
204 | ret.start = start; |
- | |
205 | ret.stop = start; |
- | |
206 | return ret; |
- | |
207 | } |
- | |
208 | - | ||
209 | /** Given a token, return the next token. */ |
- | |
210 | static token_t next_token(token_t *cur) |
- | |
211 | { |
- | |
212 | token_t ret; |
- | |
213 | - | ||
214 | if (cur->stop[1] == '\0') { |
- | |
215 | ret.kind = TK_NUL; |
- | |
216 | ret.start = cur->stop + 1; |
- | |
217 | ret.stop = ret.start; |
- | |
218 | return ret; |
- | |
219 | } |
- | |
220 | if (cur->stop[1] == '/') { |
- | |
221 | ret.kind = TK_SLASH; |
- | |
222 | ret.start = cur->stop + 1; |
- | |
223 | ret.stop = ret.start; |
- | |
224 | return ret; |
- | |
225 | } |
- | |
226 | if (cur->stop[1] == '.' && (!cur->stop[2] || cur->stop[2] == '/')) { |
- | |
227 | ret.kind = TK_DOT; |
- | |
228 | ret.start = cur->stop + 1; |
- | |
229 | ret.stop = ret.start; |
- | |
230 | return ret; |
- | |
231 | } |
- | |
232 | if (cur->stop[1] == '.' && cur->stop[2] == '.' && |
- | |
233 | (!cur->stop[3] || cur->stop[3] == '/')) { |
- | |
234 | ret.kind = TK_DOTDOT; |
- | |
235 | ret.start = cur->stop + 1; |
- | |
236 | ret.stop = cur->stop + 2; |
- | |
237 | return ret; |
- | |
238 | } |
- | |
239 | unsigned i; |
- | |
240 | for (i = 1; cur->stop[i] && cur->stop[i] != '/'; i++) |
- | |
241 | ; |
- | |
242 | ret.kind = TK_COMP; |
- | |
243 | ret.start = &cur->stop[1]; |
- | |
244 | ret.stop = &cur->stop[i - 1]; |
- | |
245 | return ret; |
- | |
246 | } |
- | |
247 | - | ||
248 | /** States used by canonify(). */ |
- | |
249 | typedef enum { |
- | |
250 | S_INI, |
- | |
251 | S_A, |
- | |
252 | S_B, |
- | |
253 | S_C, |
- | |
254 | S_ACCEPT, |
- | |
255 | S_RESTART, |
- | |
256 | S_REJECT |
- | |
257 | } state_t; |
- | |
258 | - | ||
259 | typedef struct { |
- | |
260 | state_t s; |
- | |
261 | void (* f)(token_t *, token_t *, token_t *); |
- | |
262 | } change_state_t; |
- | |
263 | - | ||
264 | /* |
- | |
265 | * Actions that can be performed when transitioning from one |
- | |
266 | * state of canonify() to another. |
- | |
267 | */ |
- | |
268 | static void set_first_slash(token_t *t, token_t *tfsl, token_t *tlcomp) |
- | |
269 | { |
- | |
270 | *tfsl = *t; |
- | |
271 | } |
- | |
272 | static void save_component(token_t *t, token_t *tfsl, token_t *tlcomp) |
- | |
273 | { |
- | |
274 | *tlcomp = *t; |
- | |
275 | } |
- | |
276 | static void terminate_slash(token_t *t, token_t *tfsl, token_t *tlcomp) |
- | |
277 | { |
- | |
278 | if (tfsl->stop[1]) /* avoid writing to a well-formatted path */ |
- | |
279 | tfsl->stop[1] = '\0'; |
- | |
280 | } |
- | |
281 | static void remove_trailing_slash(token_t *t, token_t *tfsl, token_t *tlcomp) |
- | |
282 | { |
- | |
283 | t->start[-1] = '\0'; |
- | |
284 | } |
- | |
285 | /** Eat the extra '/'.. |
- | |
286 | * |
- | |
287 | * @param t The current TK_SLASH token. |
- | |
288 | */ |
- | |
289 | static void shift_slash(token_t *t, token_t *tfsl, token_t *tlcomp) |
- | |
290 | { |
- | |
291 | char *p = t->start; |
- | |
292 | char *q = t->stop + 1; |
- | |
293 | while ((*p++ = *q++)) |
- | |
294 | ; |
- | |
295 | } |
- | |
296 | /** Eat the extra '.'. |
- | |
297 | * |
- | |
298 | * @param t The current TK_DOT token. |
- | |
299 | */ |
- | |
300 | static void shift_dot(token_t *t, token_t *tfsl, token_t *tlcomp) |
- | |
301 | { |
- | |
302 | char *p = t->start; |
- | |
303 | char *q = t->stop + 1; |
- | |
304 | while ((*p++ = *q++)) |
- | |
305 | ; |
- | |
306 | } |
- | |
307 | /** Collapse the TK_COMP TK_SLASH TK_DOTDOT pattern. |
- | |
308 | * |
- | |
309 | * @param t The current TK_DOTDOT token. |
- | |
310 | * @param tlcomp The last TK_COMP token. |
- | |
311 | */ |
- | |
312 | static void shift_dotdot(token_t *t, token_t *tfsl, token_t *tlcomp) |
- | |
313 | { |
- | |
314 | char *p = tlcomp->start; |
- | |
315 | char *q = t->stop + 1; |
- | |
316 | while ((*p++ = *q++)) |
- | |
317 | ; |
- | |
318 | } |
- | |
319 | - | ||
320 | /** Transition function for canonify(). */ |
- | |
321 | static change_state_t trans[4][6] = { |
- | |
322 | [S_INI] = { |
- | |
323 | [TK_SLASH] = { |
- | |
324 | .s = S_A, |
- | |
325 | .f = set_first_slash, |
- | |
326 | }, |
- | |
327 | [TK_DOT] = { |
- | |
328 | .s = S_REJECT, |
- | |
329 | .f = NULL, |
- | |
330 | }, |
- | |
331 | [TK_DOTDOT] = { |
- | |
332 | .s = S_REJECT, |
- | |
333 | .f = NULL, |
- | |
334 | }, |
- | |
335 | [TK_COMP] = { |
- | |
336 | .s = S_REJECT, |
- | |
337 | .f = NULL, |
- | |
338 | }, |
- | |
339 | [TK_NUL] = { |
- | |
340 | .s = S_REJECT, |
- | |
341 | .f = NULL, |
- | |
342 | }, |
- | |
343 | [TK_INVALID] = { |
- | |
344 | .s = S_REJECT, |
- | |
345 | .f = NULL, |
- | |
346 | }, |
- | |
347 | }, |
- | |
348 | [S_A] = { |
- | |
349 | [TK_SLASH] = { |
- | |
350 | .s = S_A, |
- | |
351 | .f = set_first_slash, |
- | |
352 | }, |
- | |
353 | [TK_DOT] = { |
- | |
354 | .s = S_A, |
- | |
355 | .f = NULL, |
- | |
356 | }, |
- | |
357 | [TK_DOTDOT] = { |
- | |
358 | .s = S_A, |
- | |
359 | .f = NULL, |
- | |
360 | }, |
- | |
361 | [TK_COMP] = { |
- | |
362 | .s = S_B, |
- | |
363 | .f = save_component, |
- | |
364 | }, |
- | |
365 | [TK_NUL] = { |
- | |
366 | .s = S_ACCEPT, |
- | |
367 | .f = terminate_slash, |
- | |
368 | }, |
- | |
369 | [TK_INVALID] = { |
- | |
370 | .s = S_REJECT, |
- | |
371 | .f = NULL, |
- | |
372 | }, |
- | |
373 | }, |
- | |
374 | [S_B] = { |
- | |
375 | [TK_SLASH] = { |
- | |
376 | .s = S_C, |
- | |
377 | .f = NULL, |
- | |
378 | }, |
- | |
379 | [TK_DOT] = { |
- | |
380 | .s = S_REJECT, |
- | |
381 | .f = NULL, |
- | |
382 | }, |
- | |
383 | [TK_DOTDOT] = { |
- | |
384 | .s = S_REJECT, |
- | |
385 | .f = NULL, |
- | |
386 | }, |
- | |
387 | [TK_COMP] = { |
- | |
388 | .s = S_REJECT, |
- | |
389 | .f = NULL, |
- | |
390 | }, |
- | |
391 | [TK_NUL] = { |
- | |
392 | .s = S_ACCEPT, |
- | |
393 | .f = NULL, |
- | |
394 | }, |
- | |
395 | [TK_INVALID] = { |
- | |
396 | .s = S_REJECT, |
- | |
397 | .f = NULL, |
- | |
398 | }, |
- | |
399 | }, |
- | |
400 | [S_C] = { |
- | |
401 | [TK_SLASH] = { |
- | |
402 | .s = S_RESTART, |
- | |
403 | .f = shift_slash, |
- | |
404 | }, |
- | |
405 | [TK_DOT] = { |
- | |
406 | .s = S_RESTART, |
- | |
407 | .f = shift_dot, |
- | |
408 | }, |
- | |
409 | [TK_DOTDOT] = { |
- | |
410 | .s = S_RESTART, |
- | |
411 | .f = shift_dotdot, |
- | |
412 | }, |
- | |
413 | [TK_COMP] = { |
- | |
414 | .s = S_B, |
- | |
415 | .f = save_component, |
- | |
416 | }, |
- | |
417 | [TK_NUL] = { |
- | |
418 | .s = S_ACCEPT, |
- | |
419 | .f = remove_trailing_slash, |
- | |
420 | }, |
- | |
421 | [TK_INVALID] = { |
- | |
422 | .s = S_REJECT, |
- | |
423 | .f = NULL, |
- | |
424 | }, |
- | |
425 | } |
- | |
426 | }; |
- | |
427 | - | ||
428 | /** Canonify a file system path. |
- | |
429 | * |
- | |
430 | * A file system path is canonical, if the following holds: |
- | |
431 | * 1) the path is absolute (i.e. a/b/c is not canonical) |
- | |
432 | * 2) there is no trailing slash in the path (i.e. /a/b/c is not canonical) |
- | |
433 | * 3) there is no extra slash in the path (i.e. /a//b/c is not canonical) |
- | |
434 | * 4) there is no '.' component in the path (i.e. /a/./b/c is not canonical) |
- | |
435 | * 5) there is no '..' component in the path (i.e. /a/b/../c is not canonical) |
- | |
436 | * |
- | |
437 | * This function makes a potentially non-canonical file system path canonical. |
- | |
438 | * It works in-place and requires a NULL-terminated input string. |
- | |
439 | * |
- | |
440 | * @param path Path to be canonified. |
- | |
441 | * @param lenp Pointer where the length of the final path will be |
- | |
442 | * stored. Can be NULL. |
- | |
443 | * |
- | |
444 | * @return Canonified path or NULL on failure. |
- | |
445 | */ |
- | |
446 | char *canonify(char *path, size_t *lenp) |
- | |
447 | { |
- | |
448 | state_t state; |
- | |
449 | token_t t; |
- | |
450 | token_t tfsl; /* first slash */ |
- | |
451 | token_t tlcomp; /* last component */ |
- | |
452 | if (*path != '/') |
- | |
453 | return NULL; |
- | |
454 | tfsl = slash_token(path); |
- | |
455 | restart: |
- | |
456 | state = S_INI; |
- | |
457 | t = tfsl; |
- | |
458 | tlcomp = tfsl; |
- | |
459 | while (state != S_ACCEPT && state != S_RESTART && state != S_REJECT) { |
- | |
460 | if (trans[state][t.kind].f) |
- | |
461 | trans[state][t.kind].f(&t, &tfsl, &tlcomp); |
- | |
462 | state = trans[state][t.kind].s; |
- | |
463 | t = next_token(&t); |
- | |
464 | } |
- | |
465 | - | ||
466 | switch (state) { |
- | |
467 | case S_RESTART: |
- | |
468 | goto restart; |
- | |
469 | case S_REJECT: |
- | |
470 | return NULL; |
- | |
471 | case S_ACCEPT: |
- | |
472 | if (lenp) |
- | |
473 | *lenp = (size_t)((tlcomp.stop - tfsl.start) + 1); |
- | |
474 | return tfsl.start; |
- | |
475 | default: |
- | |
476 | abort(); |
- | |
477 | } |
- | |
478 | } |
- | |
479 | - | ||
480 | /** |
180 | /** |
481 | * @} |
181 | * @} |
482 | */ |
182 | */ |