Got Mirror

Blob

Date:: Sun Mar 10 15:19:34 2019 UTC
Message:: introduce got_ref_alloc()
Actions:: History | Blame | Raw File
1 /*
2  * Copyright (c) 2018, 2019 Stefan Sperling <stsp@openbsd.org>
3  *
4  * Permission to use, copy, modify, and distribute this software for any
5  * purpose with or without fee is hereby granted, provided that the above
6  * copyright notice and this permission notice appear in all copies.
7  *
8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15  */
16 
17 #include <sys/types.h>
18 #include <sys/queue.h>
19 
20 #include <dirent.h>
21 #include <sha1.h>
22 #include <stdio.h>
23 #include <stdlib.h>
24 #include <string.h>
25 #include <util.h>
26 #include <zlib.h>
27 #include <time.h>
28 
29 #include "got_error.h"
30 #include "got_object.h"
31 #include "got_repository.h"
32 #include "got_reference.h"
33 
34 #include "got_lib_sha1.h"
35 #include "got_lib_path.h"
36 #include "got_lib_delta.h"
37 #include "got_lib_inflate.h"
38 #include "got_lib_object.h"
39 
40 #ifndef nitems
41 #define nitems(_a) (sizeof(_a) / sizeof((_a)[0]))
42 #endif
43 
44 #define GOT_REF_HEADS	"heads"
45 #define GOT_REF_TAGS	"tags"
46 #define GOT_REF_REMOTES	"remotes"
47 
48 /* A symbolic reference. */
49 struct got_symref {
50 	char *name;
51 	char *ref;
52 };
53 
54 /* A non-symbolic reference (there is no better designation). */
55 struct got_ref {
56 	char *name;
57 	u_int8_t sha1[SHA1_DIGEST_LENGTH];
58 };
59 
60 /* A reference which points to an arbitrary object. */
61 struct got_reference {
62 	unsigned int flags;
63 #define GOT_REF_IS_SYMBOLIC	0x01
64 
65 	union {
66 		struct got_ref ref;
67 		struct got_symref symref;
68 	} ref;
69 };
70 
71 static const struct got_error *
72 parse_symref(struct got_reference **ref, const char *name, const char *line)
73 {
74 	struct got_symref *symref;
75 	char *symref_name;
76 	char *symref_ref;
77 
78 	if (line[0] == '\0')
79 		return got_error(GOT_ERR_BAD_REF_DATA);
80 
81 	symref_name = strdup(name);
82 	if (symref_name == NULL)
83 		return got_error_from_errno();
84 	symref_ref = strdup(line);
85 	if (symref_ref == NULL) {
86 		const struct got_error *err = got_error_from_errno();
87 		free(symref_name);
88 		return err;
89 	}
90 
91 	*ref = calloc(1, sizeof(**ref));
92 	if (*ref == NULL)
93 		return got_error_from_errno();
94 	(*ref)->flags |= GOT_REF_IS_SYMBOLIC;
95 	symref = &((*ref)->ref.symref);
96 	symref->name = symref_name;
97 	symref->ref = symref_ref;
98 	return NULL;
99 }
100 
101 static const struct got_error *
102 parse_ref_line(struct got_reference **ref, const char *name, const char *line)
103 {
104 	struct got_object_id id;
105 
106 	if (strncmp(line, "ref: ", 5) == 0) {
107 		line += 5;
108 		return parse_symref(ref, name, line);
109 	}
110 
111 	if (!got_parse_sha1_digest(id.sha1, line))
112 		return got_error(GOT_ERR_BAD_REF_DATA);
113 
114 	return got_ref_alloc(ref, name, &id);
115 }
116 
117 static const struct got_error *
118 parse_ref_file(struct got_reference **ref, const char *name,
119     const char *abspath)
120 {
121 	const struct got_error *err = NULL;
122 	FILE *f = fopen(abspath, "rb");
123 	char *line;
124 	size_t len;
125 	const char delim[3] = {'\0', '\0', '\0'};
126 
127 	if (f == NULL)
128 		return NULL;
129 
130 	line = fparseln(f, &len, NULL, delim, 0);
131 	if (line == NULL) {
132 		err = got_error(GOT_ERR_BAD_REF_DATA);
133 		goto done;
134 	}
135 
136 	err = parse_ref_line(ref, name, line);
137 done:
138 	free(line);
139 	if (fclose(f) != 0 && err == NULL)
140 		err = got_error_from_errno();
141 	return err;
142 }
143 
144 static int
145 is_well_known_ref(const char *refname)
146 {
147 	return (strcmp(refname, GOT_REF_HEAD) == 0 ||
148 	    strcmp(refname, GOT_REF_ORIG_HEAD) == 0 ||
149 	    strcmp(refname, GOT_REF_MERGE_HEAD) == 0 ||
150 	    strcmp(refname, GOT_REF_FETCH_HEAD) == 0);
151 }
152 
153 static char *
154 get_refs_dir_path(struct got_repository *repo, const char *refname)
155 {
156 	if (is_well_known_ref(refname) || strncmp(refname, "refs/", 5) == 0)
157 		return strdup(got_repo_get_path_git_dir(repo));
158 
159 	return got_repo_get_path_refs(repo);
160 }
161 
162 const struct got_error *
163 got_ref_alloc(struct got_reference **ref, const char *name,
164     struct got_object_id *id)
165 {
166 	const struct got_error *err = NULL;
167 
168 	*ref = calloc(1, sizeof(**ref));
169 	if (*ref == NULL)
170 		return got_error_from_errno();
171 
172 	memcpy(&(*ref)->ref.ref.sha1, id->sha1, SHA1_DIGEST_LENGTH);
173 	(*ref)->ref.ref.name = strdup(name);
174 	if ((*ref)->ref.ref.name == NULL) {
175 		err = got_error_from_errno();
176 		free(*ref);
177 		*ref = NULL;
178 	}
179 	return err;
180 }
181 
182 static const struct got_error *
183 parse_packed_ref_line(struct got_reference **ref, const char *abs_refname,
184     const char *line)
185 {
186 	struct got_object_id id;
187 	const char *name;
188 
189 	*ref = NULL;
190 
191 	if (line[0] == '#' || line[0] == '^')
192 		return NULL;
193 
194 	if (!got_parse_sha1_digest(id.sha1, line))
195 		return got_error(GOT_ERR_BAD_REF_DATA);
196 
197 	if (abs_refname) {
198 		if (strcmp(line + SHA1_DIGEST_STRING_LENGTH, abs_refname) != 0)
199 			return NULL;
200 		name = abs_refname;
201 	} else
202 		name = line + SHA1_DIGEST_STRING_LENGTH;
203 
204 	return got_ref_alloc(ref, name, &id);
205 }
206 
207 static const struct got_error *
208 open_packed_ref(struct got_reference **ref, FILE *f, const char **subdirs,
209     int nsubdirs, const char *refname)
210 {
211 	const struct got_error *err = NULL;
212 	char *abs_refname;
213 	char *line;
214 	size_t len;
215 	const char delim[3] = {'\0', '\0', '\0'};
216 	int i, ref_is_absolute = (strncmp(refname, "refs/", 5) == 0);
217 
218 	*ref = NULL;
219 
220 	if (ref_is_absolute)
221 		abs_refname = (char *)refname;
222 	do {
223 		line = fparseln(f, &len, NULL, delim, 0);
224 		if (line == NULL)
225 			break;
226 		for (i = 0; i < nsubdirs; i++) {
227 			if (!ref_is_absolute &&
228 			    asprintf(&abs_refname, "refs/%s/%s", subdirs[i],
229 			    refname) == -1)
230 				return got_error_from_errno();
231 			err = parse_packed_ref_line(ref, abs_refname, line);
232 			if (!ref_is_absolute)
233 				free(abs_refname);
234 			if (err || *ref != NULL)
235 				break;
236 		}
237 		free(line);
238 		if (err)
239 			break;
240 	} while (*ref == NULL);
241 
242 	return err;
243 }
244 
245 static const struct got_error *
246 open_ref(struct got_reference **ref, const char *path_refs, const char *subdir,
247     const char *name)
248 {
249 	const struct got_error *err = NULL;
250 	char *path = NULL;
251 	char *normpath = NULL;
252 	char *absname = NULL;
253 	int ref_is_absolute = (strncmp(name, "refs/", 5) == 0);
254 	int ref_is_well_known = is_well_known_ref(name);
255 
256 	*ref = NULL;
257 
258 	if (ref_is_absolute || ref_is_well_known) {
259 		if (asprintf(&path, "%s/%s", path_refs, name) == -1)
260 			return got_error_from_errno();
261 		absname = (char *)name;
262 	} else {
263 		if (asprintf(&path, "%s/%s/%s", path_refs, subdir, name) == -1)
264 			return got_error_from_errno();
265 
266 		if (asprintf(&absname, "refs/%s/%s", subdir, name) == -1) {
267 			err = got_error_from_errno();
268 			goto done;
269 		}
270 	}
271 
272 	normpath = got_path_normalize(path);
273 	if (normpath == NULL) {
274 		err = got_error_from_errno();
275 		goto done;
276 	}
277 
278 	err = parse_ref_file(ref, absname, normpath);
279 done:
280 	if (!ref_is_absolute && !ref_is_well_known)
281 		free(absname);
282 	free(path);
283 	free(normpath);
284 	return err;
285 }
286 
287 const struct got_error *
288 got_ref_open(struct got_reference **ref, struct got_repository *repo,
289    const char *refname)
290 {
291 	const struct got_error *err = NULL;
292 	char *path_refs = NULL;
293 	const char *subdirs[] = {
294 	    GOT_REF_HEADS, GOT_REF_TAGS, GOT_REF_REMOTES
295 	};
296 	int i, well_known = is_well_known_ref(refname);
297 
298 	*ref = NULL;
299 
300 	path_refs = get_refs_dir_path(repo, refname);
301 	if (path_refs == NULL) {
302 		err = got_error_from_errno();
303 		goto done;
304 	}
305 
306 	if (!well_known) {
307 		char *packed_refs_path;
308 		FILE *f;
309 
310 		/* Search on-disk refs before packed refs! */
311 		for (i = 0; i < nitems(subdirs); i++) {
312 			err = open_ref(ref, path_refs, subdirs[i], refname);
313 			if (err || *ref)
314 				goto done;
315 		}
316 
317 		packed_refs_path = got_repo_get_path_packed_refs(repo);
318 		if (packed_refs_path == NULL) {
319 			err = got_error_from_errno();
320 			goto done;
321 		}
322 
323 		f = fopen(packed_refs_path, "rb");
324 		free(packed_refs_path);
325 		if (f != NULL) {
326 			err = open_packed_ref(ref, f, subdirs, nitems(subdirs),
327 			    refname);
328 			if (fclose(f) != 0 && err == NULL)
329 				err = got_error_from_errno();
330 			if (err || *ref)
331 				goto done;
332 		}
333 	}
334 
335 	err = open_ref(ref, path_refs, "", refname);
336 	if (err)
337 		goto done;
338 done:
339 	if (*ref == NULL)
340 		err = got_error_not_ref(refname);
341 	free(path_refs);
342 	return err;
343 }
344 
345 void
346 got_ref_close(struct got_reference *ref)
347 {
348 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
349 		free(ref->ref.symref.name);
350 	else
351 		free(ref->ref.ref.name);
352 	free(ref);
353 }
354 
355 struct got_reference *
356 got_ref_dup(struct got_reference *ref)
357 {
358 	struct got_reference *ret;
359 
360 	ret = calloc(1, sizeof(*ret));
361 	if (ret == NULL)
362 		return NULL;
363 
364 	ret->flags = ref->flags;
365 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
366 		ret->ref.symref.name = strdup(ref->ref.symref.name);
367 		if (ret->ref.symref.name == NULL) {
368 			free(ret);
369 			return NULL;
370 		}
371 		ret->ref.symref.ref = strdup(ref->ref.symref.ref);
372 		if (ret->ref.symref.ref == NULL) {
373 			free(ret->ref.symref.name);
374 			free(ret);
375 			return NULL;
376 		}
377 	} else {
378 		ref->ref.ref.name = strdup(ref->ref.ref.name);
379 		if (ref->ref.ref.name == NULL) {
380 			free(ret);
381 			return NULL;
382 		}
383 		memcpy(ret->ref.ref.sha1, ref->ref.ref.sha1,
384 		    SHA1_DIGEST_LENGTH);
385 	}
386 
387 	return ret;
388 }
389 
390 static const struct got_error *
391 resolve_symbolic_ref(struct got_reference **resolved,
392     struct got_repository *repo, struct got_reference *ref)
393 {
394 	struct got_reference *nextref;
395 	const struct got_error *err;
396 
397 	err = got_ref_open(&nextref, repo, ref->ref.symref.ref);
398 	if (err)
399 		return err;
400 
401 	if (nextref->flags & GOT_REF_IS_SYMBOLIC)
402 		err = resolve_symbolic_ref(resolved, repo, nextref);
403 	else
404 		*resolved = got_ref_dup(nextref);
405 
406 	got_ref_close(nextref);
407 	return err;
408 }
409 
410 const struct got_error *
411 got_ref_resolve(struct got_object_id **id, struct got_repository *repo,
412     struct got_reference *ref)
413 {
414 	const struct got_error *err;
415 
416 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
417 		struct got_reference *resolved = NULL;
418 		err = resolve_symbolic_ref(&resolved, repo, ref);
419 		if (err == NULL)
420 			err = got_ref_resolve(id, repo, resolved);
421 		free(resolved);
422 		return err;
423 	}
424 
425 	*id = calloc(1, sizeof(**id));
426 	if (*id == NULL)
427 		return got_error_from_errno();
428 	memcpy((*id)->sha1, ref->ref.ref.sha1, SHA1_DIGEST_LENGTH);
429 	return NULL;
430 }
431 
432 char *
433 got_ref_to_str(struct got_reference *ref)
434 {
435 	char *str;
436 
437 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
438 		return strdup(ref->ref.symref.ref);
439 
440 	str = malloc(SHA1_DIGEST_STRING_LENGTH);
441 	if (str == NULL)
442 		return NULL;
443 
444 	if (got_sha1_digest_to_str(ref->ref.ref.sha1, str,
445 	    SHA1_DIGEST_STRING_LENGTH) == NULL) {
446 		free(str);
447 		return NULL;
448 	}
449 
450 	return str;
451 }
452 
453 const char *
454 got_ref_get_name(struct got_reference *ref)
455 {
456 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
457 		return ref->ref.symref.name;
458 
459 	return ref->ref.ref.name;
460 }
461 
462 static const struct got_error *
463 insert_ref(struct got_reflist_head *refs, struct got_reference *ref,
464     struct got_repository *repo)
465 {
466 	const struct got_error *err;
467 	struct got_object_id *id;
468 	struct got_reflist_entry *new, *re, *prev;
469 	int cmp;
470 
471 	err = got_ref_resolve(&id, repo, ref);
472 	if (err)
473 		return err;
474 
475 	new = malloc(sizeof(*re));
476 	if (new == NULL) {
477 		free(id);
478 		return got_error_from_errno();
479 	}
480 	new->ref = ref;
481 	new->id = id;
482 
483 	/*
484 	 * We must de-duplicate entries on insert because packed-refs may
485 	 * contain redundant entries. On-disk refs take precedence.
486 	 * This code assumes that on-disk revs are read before packed-refs.
487 	 * We're iterating the list anyway, so insert elements sorted by name.
488 	 */
489 	re = SIMPLEQ_FIRST(refs);
490 	while (re) {
491 		cmp = got_path_cmp(got_ref_get_name(re->ref),
492 		    got_ref_get_name(ref));
493 		if (cmp == 0) {
494 			free(ref); /* duplicate */
495 			return NULL;
496 		} else if (cmp > 0) {
497 			if (prev)
498 				SIMPLEQ_INSERT_AFTER(refs, prev, new, entry);
499 			else
500 				SIMPLEQ_INSERT_HEAD(refs, new, entry);
501 			return NULL;
502 		} else {
503 			prev = re;
504 			re = SIMPLEQ_NEXT(re, entry);
505 		}
506 	}
507 
508 	SIMPLEQ_INSERT_TAIL(refs, new, entry);
509 	return NULL;
510 }
511 
512 static const struct got_error *
513 gather_on_disk_refs(struct got_reflist_head *refs, const char *path_refs,
514     const char *subdir, struct got_repository *repo)
515 {
516 	const struct got_error *err = NULL;
517 	DIR *d = NULL;
518 	char *path_subdir;
519 
520 	if (asprintf(&path_subdir, "%s/%s", path_refs, subdir) == -1)
521 		return got_error_from_errno();
522 
523 	d = opendir(path_subdir);
524 	if (d == NULL)
525 		goto done;
526 
527 	while (1) {
528 		struct dirent *dent;
529 		struct got_reference *ref;
530 		char *child;
531 
532 		dent = readdir(d);
533 		if (dent == NULL)
534 			break;
535 
536 		if (strcmp(dent->d_name, ".") == 0 ||
537 		    strcmp(dent->d_name, "..") == 0)
538 			continue;
539 
540 		switch (dent->d_type) {
541 		case DT_REG:
542 			err = open_ref(&ref, path_refs, subdir, dent->d_name);
543 			if (err)
544 				goto done;
545 			if (ref) {
546 				err = insert_ref(refs, ref, repo);
547 				if (err)
548 					goto done;
549 			}
550 			break;
551 		case DT_DIR:
552 			if (asprintf(&child, "%s%s%s", subdir,
553 			    subdir[0] == '\0' ? "" : "/", dent->d_name) == -1) {
554 				err = got_error_from_errno();
555 				break;
556 			}
557 			err = gather_on_disk_refs(refs, path_refs, child, repo);
558 			free(child);
559 			break;
560 		default:
561 			break;
562 		}
563 	}
564 done:
565 	if (d)
566 		closedir(d);
567 	free(path_subdir);
568 	return err;
569 }
570 
571 const struct got_error *
572 got_ref_list(struct got_reflist_head *refs, struct got_repository *repo)
573 {
574 	const struct got_error *err;
575 	char *packed_refs_path, *path_refs = NULL;
576 	FILE *f = NULL;
577 	struct got_reference *ref;
578 
579 	/* HEAD ref should always exist. */
580 	path_refs = get_refs_dir_path(repo, GOT_REF_HEAD);
581 	if (path_refs == NULL) {
582 		err = got_error_from_errno();
583 		goto done;
584 	}
585 	err = open_ref(&ref, path_refs, "", GOT_REF_HEAD);
586 	if (err)
587 		goto done;
588 	err = insert_ref(refs, ref, repo);
589 	if (err)
590 		goto done;
591 
592 	/* Gather on-disk refs before parsing packed-refs. */
593 	free(path_refs);
594 	path_refs = get_refs_dir_path(repo, "");
595 	if (path_refs == NULL) {
596 		err = got_error_from_errno();
597 		goto done;
598 	}
599 	err = gather_on_disk_refs(refs, path_refs, "", repo);
600 	if (err)
601 		goto done;
602 
603 	/*
604 	 * The packed-refs file may contain redundant entries, in which
605 	 * case on-disk refs take precedence.
606 	 */
607 	packed_refs_path = got_repo_get_path_packed_refs(repo);
608 	if (packed_refs_path == NULL) {
609 		err = got_error_from_errno();
610 		goto done;
611 	}
612 
613 	f = fopen(packed_refs_path, "r");
614 	free(packed_refs_path);
615 	if (f) {
616 		char *line;
617 		size_t len;
618 		const char delim[3] = {'\0', '\0', '\0'};
619 		while (1) {
620 			line = fparseln(f, &len, NULL, delim, 0);
621 			if (line == NULL)
622 				break;
623 			err = parse_packed_ref_line(&ref, NULL, line);
624 			if (err)
625 				goto done;
626 			if (ref) {
627 				err = insert_ref(refs, ref, repo);
628 				if (err)
629 					goto done;
630 			}
631 		}
632 	}
633 done:
634 	free(path_refs);
635 	if (f && fclose(f) != 0 && err == NULL)
636 		err = got_error_from_errno();
637 	return err;
638 }