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1479465f GJ |
1 | /* |
2 | * libdpkg - Debian packaging suite library routines | |
3 | * treewalk.c - directory tree walk support | |
4 | * | |
5 | * Copyright © 2013-2016 Guillem Jover <guillem@debian.org> | |
6 | * | |
7 | * This is free software; you can redistribute it and/or modify | |
8 | * it under the terms of the GNU General Public License as published by | |
9 | * the Free Software Foundation; either version 2 of the License, or | |
10 | * (at your option) any later version. | |
11 | * | |
12 | * This is distributed in the hope that it will be useful, | |
13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | * GNU General Public License for more details. | |
16 | * | |
17 | * You should have received a copy of the GNU General Public License | |
18 | * along with this program. If not, see <http://www.gnu.org/licenses/>. | |
19 | */ | |
20 | ||
21 | #include <config.h> | |
22 | #include <compat.h> | |
23 | ||
24 | #include <sys/stat.h> | |
25 | #include <sys/types.h> | |
26 | #include <dirent.h> | |
27 | #include <string.h> | |
28 | #include <stdbool.h> | |
29 | #include <stdio.h> | |
30 | #include <stdlib.h> | |
31 | ||
32 | #include <dpkg/dpkg.h> | |
33 | #include <dpkg/i18n.h> | |
34 | #include <dpkg/treewalk.h> | |
35 | ||
36 | /* treenode functions. */ | |
37 | ||
38 | typedef int treewalk_stat_func(const char *pathname, struct stat *st); | |
39 | ||
40 | struct treenode { | |
41 | struct treenode *up; /* Parent dir. */ | |
42 | struct treenode *next; /* Next node in dir. */ | |
43 | struct treenode **down; /* Dir contents. */ | |
44 | ||
45 | char *pathname; /* Node pathname. */ | |
46 | char *virtname; /* Node virtname. */ | |
47 | char *name; /* Node name. */ | |
48 | ||
49 | struct stat *stat; /* Node metadata. */ | |
50 | mode_t mode; | |
51 | ||
52 | size_t pathname_len; /* Node pathname length. */ | |
53 | ||
54 | size_t down_used; /* Number of used nodes in dir. */ | |
55 | size_t down_size; /* Number of allocated nodes in dir. */ | |
56 | }; | |
57 | ||
58 | static inline struct treenode * | |
59 | treenode_alloc(void) | |
60 | { | |
61 | return m_calloc(1, sizeof(struct treenode)); | |
62 | } | |
63 | ||
64 | static struct treenode * | |
65 | treenode_root_new(const char *rootdir) | |
66 | { | |
67 | struct treenode *node; | |
68 | ||
69 | node = treenode_alloc(); | |
70 | node->up = NULL; | |
71 | node->pathname = m_strdup(rootdir); | |
72 | node->pathname_len = strlen(node->pathname); | |
73 | node->virtname = node->pathname + node->pathname_len; | |
74 | node->name = strrchr(node->pathname, '/'); | |
75 | if (node->name == NULL) | |
76 | node->name = node->pathname; | |
77 | else | |
78 | node->name++; | |
79 | ||
80 | return node; | |
81 | } | |
82 | ||
83 | static struct treenode * | |
84 | treenode_node_new(struct treenode *root, struct treenode *dir, const char *name) | |
85 | { | |
86 | struct treenode *node; | |
87 | ||
88 | node = treenode_alloc(); | |
89 | node->up = dir; | |
90 | ||
91 | node->pathname = str_fmt("%s/%s", node->up->pathname, name); | |
92 | node->pathname_len = strlen(node->pathname); | |
93 | node->virtname = node->pathname + root->pathname_len + 1; | |
94 | node->name = node->pathname + node->up->pathname_len + 1; | |
95 | ||
96 | return node; | |
97 | } | |
98 | ||
99 | static void | |
100 | treenode_stat(struct treenode *node, treewalk_stat_func *stat_func) | |
101 | { | |
102 | if (node->stat) | |
103 | return; | |
104 | ||
105 | node->stat = m_malloc(sizeof(*node->stat)); | |
106 | ||
107 | if (stat_func(node->pathname, node->stat) < 0) | |
108 | ohshite(_("cannot stat pathname '%s'"), node->pathname); | |
109 | ||
110 | node->mode = node->stat->st_mode; | |
111 | } | |
112 | ||
113 | static mode_t | |
114 | dirent_to_mode_type(struct dirent *e) | |
115 | { | |
116 | #ifdef _DIRENT_HAVE_D_TYPE | |
117 | switch (e->d_type) { | |
118 | case DT_REG: | |
119 | return S_IFREG; | |
120 | case DT_DIR: | |
121 | return S_IFDIR; | |
122 | case DT_LNK: | |
123 | return S_IFLNK; | |
124 | case DT_CHR: | |
125 | return S_IFCHR; | |
126 | case DT_BLK: | |
127 | return S_IFBLK; | |
128 | case DT_FIFO: | |
129 | return S_IFIFO; | |
130 | case DT_SOCK: | |
131 | return S_IFSOCK; | |
132 | case DT_UNKNOWN: | |
133 | default: | |
134 | return 0; | |
135 | } | |
136 | #else | |
137 | return 0; | |
138 | #endif | |
139 | } | |
140 | ||
141 | static void | |
142 | treenode_stat_shallow(struct treenode *node, struct dirent *e, | |
143 | treewalk_stat_func *stat_func) | |
144 | { | |
145 | mode_t mode; | |
146 | ||
147 | mode = dirent_to_mode_type(e); | |
148 | if (mode == 0 || S_ISDIR(mode) || S_ISLNK(mode)) | |
149 | treenode_stat(node, stat_func); | |
150 | else | |
151 | node->mode |= mode; | |
152 | } | |
153 | ||
154 | const char * | |
155 | treenode_get_name(struct treenode *node) | |
156 | { | |
157 | return node->name; | |
158 | } | |
159 | ||
160 | const char * | |
161 | treenode_get_pathname(struct treenode *node) | |
162 | { | |
163 | return node->pathname; | |
164 | } | |
165 | ||
166 | const char * | |
167 | treenode_get_virtname(struct treenode *node) | |
168 | { | |
169 | return node->virtname; | |
170 | } | |
171 | ||
172 | mode_t | |
173 | treenode_get_mode(struct treenode *node) | |
174 | { | |
175 | return node->mode; | |
176 | } | |
177 | ||
178 | struct stat * | |
179 | treenode_get_stat(struct treenode *node) | |
180 | { | |
181 | treenode_stat(node, lstat); | |
182 | return node->stat; | |
183 | } | |
184 | ||
185 | struct treenode * | |
186 | treenode_get_parent(struct treenode *node) | |
187 | { | |
188 | return node->up; | |
189 | } | |
190 | ||
191 | static inline bool | |
192 | treenode_is_dir(struct treenode *node) | |
193 | { | |
194 | return node && S_ISDIR(node->mode); | |
195 | } | |
196 | ||
197 | static void | |
198 | treenode_resize_down(struct treenode *node) | |
199 | { | |
200 | size_t new_size; | |
201 | ||
202 | if (node->down_size) | |
203 | node->down_size *= 2; | |
204 | else if (node->stat->st_nlink > 4) | |
205 | node->down_size = node->stat->st_nlink * 2; | |
206 | else | |
207 | node->down_size = 8; | |
208 | ||
209 | new_size = node->down_size * sizeof(struct treenode *); | |
210 | node->down = m_realloc(node->down, new_size); | |
211 | } | |
212 | ||
213 | static int | |
214 | treenode_cmp(const void *a, const void *b) | |
215 | { | |
216 | return strcmp((*(const struct treenode **)a)->name, | |
217 | (*(const struct treenode **)b)->name); | |
218 | } | |
219 | ||
220 | static void | |
221 | treenode_sort_down(struct treenode *dir) | |
222 | { | |
223 | size_t i; | |
224 | ||
225 | qsort(dir->down, dir->down_used, sizeof(struct treenode *), treenode_cmp); | |
226 | ||
227 | /* Relink the nodes. */ | |
228 | for (i = 0; i < dir->down_used - 1; i++) | |
229 | dir->down[i]->next = dir->down[i + 1]; | |
230 | dir->down[i]->next = NULL; | |
231 | } | |
232 | ||
233 | static void | |
234 | treenode_fill_down(struct treenode *root, struct treenode *dir, | |
235 | enum treewalk_options options) | |
236 | { | |
237 | DIR *d; | |
238 | struct dirent *e; | |
239 | treewalk_stat_func *stat_func; | |
240 | ||
241 | if (options & TREEWALK_FOLLOW_LINKS) | |
242 | stat_func = stat; | |
243 | else | |
244 | stat_func = lstat; | |
245 | ||
246 | d = opendir(dir->pathname); | |
247 | if (!d) | |
248 | ohshite(_("cannot open directory '%s'"), dir->pathname); | |
249 | ||
250 | while ((e = readdir(d)) != NULL) { | |
251 | struct treenode *node; | |
252 | ||
253 | if (strcmp(e->d_name, ".") == 0 || | |
254 | strcmp(e->d_name, "..") == 0) | |
255 | continue; | |
256 | ||
257 | if (dir->down_used >= dir->down_size) | |
258 | treenode_resize_down(dir); | |
259 | ||
260 | node = treenode_node_new(root, dir, e->d_name); | |
261 | if (options & TREEWALK_FORCE_STAT) | |
262 | treenode_stat(node, stat_func); | |
263 | else | |
264 | treenode_stat_shallow(node, e, stat_func); | |
265 | ||
266 | dir->down[dir->down_used] = node; | |
267 | dir->down_used++; | |
268 | } | |
269 | ||
270 | closedir(d); | |
271 | } | |
272 | ||
273 | static void | |
274 | treenode_free_node(struct treenode *node) | |
275 | { | |
276 | free(node->pathname); | |
277 | free(node); | |
278 | } | |
279 | ||
280 | static void | |
281 | treenode_free_down(struct treenode *node) | |
282 | { | |
283 | size_t i; | |
284 | ||
285 | if (!node->down_size) | |
286 | return; | |
287 | ||
288 | for (i = 0; i < node->down_used; i++) | |
289 | treenode_free_node(node->down[i]); | |
290 | free(node->down); | |
291 | } | |
292 | ||
293 | ||
294 | /* treeroot functions. */ | |
295 | ||
296 | struct treeroot { | |
297 | struct treenode *rootnode; | |
298 | ||
299 | struct treenode *curdir; | |
300 | struct treenode *curnode; | |
301 | ||
302 | enum treewalk_options options; | |
303 | struct treewalk_funcs func; | |
304 | }; | |
305 | ||
306 | static inline void | |
307 | treeroot_set_curdir(struct treeroot *tree, struct treenode *node) | |
308 | { | |
309 | tree->curdir = node; | |
310 | } | |
311 | ||
312 | static inline void | |
313 | treeroot_set_curnode(struct treeroot *tree, struct treenode *node) | |
314 | { | |
315 | tree->curnode = node; | |
316 | } | |
317 | ||
318 | static bool | |
319 | treeroot_skip_node(struct treeroot *tree, struct treenode *node) | |
320 | { | |
321 | if (tree->func.skip) | |
322 | return tree->func.skip(node); | |
323 | ||
324 | return false; | |
325 | } | |
326 | ||
327 | static void | |
328 | treeroot_fill_node(struct treeroot *tree, struct treenode *dir) | |
329 | { | |
330 | treenode_fill_down(tree->rootnode, dir, tree->options); | |
331 | } | |
332 | ||
333 | static void | |
334 | treeroot_sort_node(struct treeroot *tree, struct treenode *dir) | |
335 | { | |
336 | static struct treenode *down_empty[] = { NULL, NULL }; | |
337 | ||
338 | if (dir->down_used == 0) | |
339 | dir->down = down_empty; | |
340 | else if (tree->func.sort) | |
341 | tree->func.sort(dir); | |
342 | else | |
343 | treenode_sort_down(dir); | |
344 | } | |
345 | ||
346 | static void | |
347 | treeroot_visit_node(struct treeroot *tree, struct treenode *node) | |
348 | { | |
349 | if (tree->func.visit == NULL) | |
350 | return; | |
351 | ||
352 | if (!treeroot_skip_node(tree, node)) | |
353 | tree->func.visit(node); | |
354 | } | |
355 | ||
356 | /** | |
357 | * Open a new tree to be walked. | |
358 | * | |
359 | * @param rootdir The root directory to start walking the tree. | |
360 | * @param options The options specifying how to walk the tree. | |
361 | * @param func The functions callbacks. | |
362 | */ | |
363 | struct treeroot * | |
364 | treewalk_open(const char *rootdir, enum treewalk_options options, | |
365 | struct treewalk_funcs *func) | |
366 | { | |
367 | struct treeroot *tree; | |
368 | struct treenode *root; | |
369 | ||
370 | tree = m_malloc(sizeof(struct treeroot)); | |
371 | ||
372 | tree->options = options; | |
373 | if (func) | |
374 | tree->func = *func; | |
375 | else | |
376 | tree->func = (struct treewalk_funcs){ }; | |
377 | ||
378 | root = treenode_root_new(rootdir); | |
379 | treenode_stat(root, lstat); | |
380 | ||
381 | if (!treenode_is_dir(root)) | |
382 | ohshit(_("treewalk root %s is not a directory"), rootdir); | |
383 | ||
384 | treeroot_set_curnode(tree, root); | |
385 | tree->rootnode = tree->curdir = root; | |
386 | ||
387 | return tree; | |
388 | } | |
389 | ||
390 | /** | |
391 | * Return the current node. | |
392 | * | |
393 | * This function is only needed if you want to start walking the tree from | |
394 | * the root node. With something like: | |
395 | * | |
396 | * @code | |
397 | * struct treeroot *tree; | |
398 | * struct treenode *node; | |
399 | * | |
400 | * tree = treewalk_open(...); | |
401 | * for (node = treewalk_node(tree); node; node = treewalk_next(tree)) | |
402 | * visitor(node); | |
403 | * treewalk_close(tree); | |
404 | * @endcode | |
405 | * | |
406 | * @param tree The tree structure. | |
407 | */ | |
408 | struct treenode * | |
409 | treewalk_node(struct treeroot *tree) | |
410 | { | |
411 | return tree->curnode; | |
412 | } | |
413 | ||
414 | /** | |
415 | * Return the next node. | |
416 | * | |
417 | * This function works basically as an iterator. And will return NULL when | |
418 | * the whole tree has been traversed. When starting it will skip the root | |
419 | * node, so you might want to use treewalk_node() to get that, otherwise | |
420 | * you could use it like this: | |
421 | * | |
422 | * @code | |
423 | * struct treeroot *tree; | |
424 | * struct treenode *node; | |
425 | * | |
426 | * tree = treewalk_open(...); | |
427 | * while ((node = treewalk_next(tree)) | |
428 | * visitor(node); | |
429 | * treewalk_close(tree); | |
430 | * @endcode | |
431 | * | |
432 | * @param tree The tree structure. | |
433 | */ | |
434 | struct treenode * | |
435 | treewalk_next(struct treeroot *tree) | |
436 | { | |
437 | struct treenode *node; | |
438 | ||
439 | node = tree->curnode; | |
440 | ||
441 | /* Handle end of tree. */ | |
442 | if (node == NULL) | |
443 | return NULL; | |
444 | ||
445 | /* Get next node, descending or sidewide. */ | |
446 | if (treenode_is_dir(node) && !treeroot_skip_node(tree, node)) { | |
447 | struct treenode *dir; | |
448 | ||
449 | treeroot_fill_node(tree, node); | |
450 | treeroot_sort_node(tree, node); | |
451 | treeroot_set_curdir(tree, node); | |
452 | ||
453 | /* Check for directory loops. */ | |
454 | for (dir = node->up; dir; dir = dir->up) { | |
455 | if (dir->stat->st_dev == node->stat->st_dev && | |
456 | dir->stat->st_ino == node->stat->st_ino) | |
457 | break; | |
458 | } | |
459 | ||
460 | /* Skip directory loops. */ | |
461 | if (dir) | |
462 | node = node->next; | |
463 | else | |
464 | node = node->down[0]; | |
465 | } else { | |
466 | node = node->next; | |
467 | } | |
468 | ||
469 | /* Back track node, ascending. */ | |
470 | while (node == NULL) { | |
471 | struct treenode *olddir = tree->curdir; | |
472 | ||
473 | if (tree->curdir->next) { | |
474 | /* Next entry in the parent directory. */ | |
475 | node = tree->curdir->next; | |
476 | treeroot_set_curdir(tree, olddir->up); | |
477 | treenode_free_down(olddir); | |
478 | } else if (tree->curdir->up) { | |
479 | /* Next entry in the grand-parent directory. */ | |
480 | node = tree->curdir->up->next; | |
481 | treeroot_set_curdir(tree, olddir->up->up); | |
482 | treenode_free_down(olddir); | |
483 | treenode_free_down(olddir->up); | |
484 | } else { | |
485 | /* Otherwise, we're in the rootnode. */ | |
486 | treenode_free_down(olddir); | |
487 | treenode_free_node(olddir); | |
488 | break; | |
489 | } | |
490 | ||
491 | if (tree->curdir == NULL) | |
492 | break; | |
493 | } | |
494 | ||
495 | treeroot_set_curnode(tree, node); | |
496 | ||
497 | return node; | |
498 | } | |
499 | ||
500 | /** | |
501 | * Closes the tree being walked. | |
502 | * | |
503 | * It will free any resources previously allocated. | |
504 | */ | |
505 | void | |
506 | treewalk_close(struct treeroot *tree) | |
507 | { | |
508 | free(tree); | |
509 | } | |
510 | ||
511 | /** | |
512 | * Tree walker. | |
513 | * | |
514 | * @param rootdir The root directory to start walking the tree. | |
515 | * @param options The options specifying how to walk the tree. | |
516 | * @param func The function callbacks. | |
517 | */ | |
518 | int | |
519 | treewalk(const char *rootdir, enum treewalk_options options, | |
520 | struct treewalk_funcs *func) | |
521 | { | |
522 | struct treeroot *tree; | |
523 | struct treenode *node; | |
524 | ||
525 | tree = treewalk_open(rootdir, options, func); | |
526 | ||
527 | /* Breath first visit. */ | |
528 | for (node = treewalk_node(tree); node; node = treewalk_next(tree)) | |
529 | treeroot_visit_node(tree, node); | |
530 | ||
531 | treewalk_close(tree); | |
532 | ||
533 | return 0; | |
534 | } |