Add callback data to for_each_ref() family.
[git/git.git] / refs.c
1 #include "refs.h"
2 #include "cache.h"
3
4 #include <errno.h>
5
6 struct ref_list {
7 struct ref_list *next;
8 unsigned char sha1[20];
9 char name[FLEX_ARRAY];
10 };
11
12 static const char *parse_ref_line(char *line, unsigned char *sha1)
13 {
14 /*
15 * 42: the answer to everything.
16 *
17 * In this case, it happens to be the answer to
18 * 40 (length of sha1 hex representation)
19 * +1 (space in between hex and name)
20 * +1 (newline at the end of the line)
21 */
22 int len = strlen(line) - 42;
23
24 if (len <= 0)
25 return NULL;
26 if (get_sha1_hex(line, sha1) < 0)
27 return NULL;
28 if (!isspace(line[40]))
29 return NULL;
30 line += 41;
31 if (isspace(*line))
32 return NULL;
33 if (line[len] != '\n')
34 return NULL;
35 line[len] = 0;
36 return line;
37 }
38
39 static struct ref_list *add_ref(const char *name, const unsigned char *sha1, struct ref_list *list)
40 {
41 int len;
42 struct ref_list **p = &list, *entry;
43
44 /* Find the place to insert the ref into.. */
45 while ((entry = *p) != NULL) {
46 int cmp = strcmp(entry->name, name);
47 if (cmp > 0)
48 break;
49
50 /* Same as existing entry? */
51 if (!cmp)
52 return list;
53 p = &entry->next;
54 }
55
56 /* Allocate it and add it in.. */
57 len = strlen(name) + 1;
58 entry = xmalloc(sizeof(struct ref_list) + len);
59 hashcpy(entry->sha1, sha1);
60 memcpy(entry->name, name, len);
61 entry->next = *p;
62 *p = entry;
63 return list;
64 }
65
66 static struct ref_list *get_packed_refs(void)
67 {
68 static int did_refs = 0;
69 static struct ref_list *refs = NULL;
70
71 if (!did_refs) {
72 FILE *f = fopen(git_path("packed-refs"), "r");
73 if (f) {
74 struct ref_list *list = NULL;
75 char refline[PATH_MAX];
76 while (fgets(refline, sizeof(refline), f)) {
77 unsigned char sha1[20];
78 const char *name = parse_ref_line(refline, sha1);
79 if (!name)
80 continue;
81 list = add_ref(name, sha1, list);
82 }
83 fclose(f);
84 refs = list;
85 }
86 did_refs = 1;
87 }
88 return refs;
89 }
90
91 static struct ref_list *get_ref_dir(const char *base, struct ref_list *list)
92 {
93 DIR *dir = opendir(git_path("%s", base));
94
95 if (dir) {
96 struct dirent *de;
97 int baselen = strlen(base);
98 char *ref = xmalloc(baselen + 257);
99
100 memcpy(ref, base, baselen);
101 if (baselen && base[baselen-1] != '/')
102 ref[baselen++] = '/';
103
104 while ((de = readdir(dir)) != NULL) {
105 unsigned char sha1[20];
106 struct stat st;
107 int namelen;
108
109 if (de->d_name[0] == '.')
110 continue;
111 namelen = strlen(de->d_name);
112 if (namelen > 255)
113 continue;
114 if (has_extension(de->d_name, ".lock"))
115 continue;
116 memcpy(ref + baselen, de->d_name, namelen+1);
117 if (stat(git_path("%s", ref), &st) < 0)
118 continue;
119 if (S_ISDIR(st.st_mode)) {
120 list = get_ref_dir(ref, list);
121 continue;
122 }
123 if (read_ref(ref, sha1) < 0) {
124 error("%s points nowhere!", ref);
125 continue;
126 }
127 list = add_ref(ref, sha1, list);
128 }
129 free(ref);
130 closedir(dir);
131 }
132 return list;
133 }
134
135 static struct ref_list *get_loose_refs(void)
136 {
137 static int did_refs = 0;
138 static struct ref_list *refs = NULL;
139
140 if (!did_refs) {
141 refs = get_ref_dir("refs", NULL);
142 did_refs = 1;
143 }
144 return refs;
145 }
146
147 /* We allow "recursive" symbolic refs. Only within reason, though */
148 #define MAXDEPTH 5
149
150 const char *resolve_ref(const char *ref, unsigned char *sha1, int reading)
151 {
152 int depth = MAXDEPTH, len;
153 char buffer[256];
154 static char ref_buffer[256];
155
156 for (;;) {
157 const char *path = git_path("%s", ref);
158 struct stat st;
159 char *buf;
160 int fd;
161
162 if (--depth < 0)
163 return NULL;
164
165 /* Special case: non-existing file.
166 * Not having the refs/heads/new-branch is OK
167 * if we are writing into it, so is .git/HEAD
168 * that points at refs/heads/master still to be
169 * born. It is NOT OK if we are resolving for
170 * reading.
171 */
172 if (lstat(path, &st) < 0) {
173 struct ref_list *list = get_packed_refs();
174 while (list) {
175 if (!strcmp(ref, list->name)) {
176 hashcpy(sha1, list->sha1);
177 return ref;
178 }
179 list = list->next;
180 }
181 if (reading || errno != ENOENT)
182 return NULL;
183 hashclr(sha1);
184 return ref;
185 }
186
187 /* Follow "normalized" - ie "refs/.." symlinks by hand */
188 if (S_ISLNK(st.st_mode)) {
189 len = readlink(path, buffer, sizeof(buffer)-1);
190 if (len >= 5 && !memcmp("refs/", buffer, 5)) {
191 buffer[len] = 0;
192 strcpy(ref_buffer, buffer);
193 ref = ref_buffer;
194 continue;
195 }
196 }
197
198 /*
199 * Anything else, just open it and try to use it as
200 * a ref
201 */
202 fd = open(path, O_RDONLY);
203 if (fd < 0)
204 return NULL;
205 len = read(fd, buffer, sizeof(buffer)-1);
206 close(fd);
207
208 /*
209 * Is it a symbolic ref?
210 */
211 if (len < 4 || memcmp("ref:", buffer, 4))
212 break;
213 buf = buffer + 4;
214 len -= 4;
215 while (len && isspace(*buf))
216 buf++, len--;
217 while (len && isspace(buf[len-1]))
218 len--;
219 buf[len] = 0;
220 memcpy(ref_buffer, buf, len + 1);
221 ref = ref_buffer;
222 }
223 if (len < 40 || get_sha1_hex(buffer, sha1))
224 return NULL;
225 return ref;
226 }
227
228 int create_symref(const char *ref_target, const char *refs_heads_master)
229 {
230 const char *lockpath;
231 char ref[1000];
232 int fd, len, written;
233 const char *git_HEAD = git_path("%s", ref_target);
234
235 #ifndef NO_SYMLINK_HEAD
236 if (prefer_symlink_refs) {
237 unlink(git_HEAD);
238 if (!symlink(refs_heads_master, git_HEAD))
239 return 0;
240 fprintf(stderr, "no symlink - falling back to symbolic ref\n");
241 }
242 #endif
243
244 len = snprintf(ref, sizeof(ref), "ref: %s\n", refs_heads_master);
245 if (sizeof(ref) <= len) {
246 error("refname too long: %s", refs_heads_master);
247 return -1;
248 }
249 lockpath = mkpath("%s.lock", git_HEAD);
250 fd = open(lockpath, O_CREAT | O_EXCL | O_WRONLY, 0666);
251 written = write(fd, ref, len);
252 close(fd);
253 if (written != len) {
254 unlink(lockpath);
255 error("Unable to write to %s", lockpath);
256 return -2;
257 }
258 if (rename(lockpath, git_HEAD) < 0) {
259 unlink(lockpath);
260 error("Unable to create %s", git_HEAD);
261 return -3;
262 }
263 if (adjust_shared_perm(git_HEAD)) {
264 unlink(lockpath);
265 error("Unable to fix permissions on %s", lockpath);
266 return -4;
267 }
268 return 0;
269 }
270
271 int read_ref(const char *ref, unsigned char *sha1)
272 {
273 if (resolve_ref(ref, sha1, 1))
274 return 0;
275 return -1;
276 }
277
278 static int do_for_each_ref(const char *base, each_ref_fn fn, int trim, void *cb_data)
279 {
280 int retval;
281 struct ref_list *packed = get_packed_refs();
282 struct ref_list *loose = get_loose_refs();
283
284 while (packed && loose) {
285 struct ref_list *entry;
286 int cmp = strcmp(packed->name, loose->name);
287 if (!cmp) {
288 packed = packed->next;
289 continue;
290 }
291 if (cmp > 0) {
292 entry = loose;
293 loose = loose->next;
294 } else {
295 entry = packed;
296 packed = packed->next;
297 }
298 if (strncmp(base, entry->name, trim))
299 continue;
300 if (is_null_sha1(entry->sha1))
301 continue;
302 if (!has_sha1_file(entry->sha1)) {
303 error("%s does not point to a valid object!", entry->name);
304 continue;
305 }
306 retval = fn(entry->name + trim, entry->sha1, cb_data);
307 if (retval)
308 return retval;
309 }
310
311 packed = packed ? packed : loose;
312 while (packed) {
313 if (!strncmp(base, packed->name, trim)) {
314 retval = fn(packed->name + trim, packed->sha1, cb_data);
315 if (retval)
316 return retval;
317 }
318 packed = packed->next;
319 }
320 return 0;
321 }
322
323 int head_ref(each_ref_fn fn, void *cb_data)
324 {
325 unsigned char sha1[20];
326 if (!read_ref("HEAD", sha1))
327 return fn("HEAD", sha1, cb_data);
328 return 0;
329 }
330
331 int for_each_ref(each_ref_fn fn, void *cb_data)
332 {
333 return do_for_each_ref("refs/", fn, 0, cb_data);
334 }
335
336 int for_each_tag_ref(each_ref_fn fn, void *cb_data)
337 {
338 return do_for_each_ref("refs/tags/", fn, 10, cb_data);
339 }
340
341 int for_each_branch_ref(each_ref_fn fn, void *cb_data)
342 {
343 return do_for_each_ref("refs/heads/", fn, 11, cb_data);
344 }
345
346 int for_each_remote_ref(each_ref_fn fn, void *cb_data)
347 {
348 return do_for_each_ref("refs/remotes/", fn, 13, cb_data);
349 }
350
351 /* NEEDSWORK: This is only used by ssh-upload and it should go; the
352 * caller should do resolve_ref or read_ref like everybody else. Or
353 * maybe everybody else should use get_ref_sha1() instead of doing
354 * read_ref().
355 */
356 int get_ref_sha1(const char *ref, unsigned char *sha1)
357 {
358 if (check_ref_format(ref))
359 return -1;
360 return read_ref(mkpath("refs/%s", ref), sha1);
361 }
362
363 /*
364 * Make sure "ref" is something reasonable to have under ".git/refs/";
365 * We do not like it if:
366 *
367 * - any path component of it begins with ".", or
368 * - it has double dots "..", or
369 * - it has ASCII control character, "~", "^", ":" or SP, anywhere, or
370 * - it ends with a "/".
371 */
372
373 static inline int bad_ref_char(int ch)
374 {
375 return (((unsigned) ch) <= ' ' ||
376 ch == '~' || ch == '^' || ch == ':' ||
377 /* 2.13 Pattern Matching Notation */
378 ch == '?' || ch == '*' || ch == '[');
379 }
380
381 int check_ref_format(const char *ref)
382 {
383 int ch, level;
384 const char *cp = ref;
385
386 level = 0;
387 while (1) {
388 while ((ch = *cp++) == '/')
389 ; /* tolerate duplicated slashes */
390 if (!ch)
391 return -1; /* should not end with slashes */
392
393 /* we are at the beginning of the path component */
394 if (ch == '.' || bad_ref_char(ch))
395 return -1;
396
397 /* scan the rest of the path component */
398 while ((ch = *cp++) != 0) {
399 if (bad_ref_char(ch))
400 return -1;
401 if (ch == '/')
402 break;
403 if (ch == '.' && *cp == '.')
404 return -1;
405 }
406 level++;
407 if (!ch) {
408 if (level < 2)
409 return -1; /* at least of form "heads/blah" */
410 return 0;
411 }
412 }
413 }
414
415 static struct ref_lock *verify_lock(struct ref_lock *lock,
416 const unsigned char *old_sha1, int mustexist)
417 {
418 if (!resolve_ref(lock->ref_name, lock->old_sha1, mustexist)) {
419 error("Can't verify ref %s", lock->ref_name);
420 unlock_ref(lock);
421 return NULL;
422 }
423 if (hashcmp(lock->old_sha1, old_sha1)) {
424 error("Ref %s is at %s but expected %s", lock->ref_name,
425 sha1_to_hex(lock->old_sha1), sha1_to_hex(old_sha1));
426 unlock_ref(lock);
427 return NULL;
428 }
429 return lock;
430 }
431
432 static struct ref_lock *lock_ref_sha1_basic(const char *ref,
433 int plen,
434 const unsigned char *old_sha1, int mustexist)
435 {
436 char *ref_file;
437 const char *orig_ref = ref;
438 struct ref_lock *lock;
439 struct stat st;
440
441 lock = xcalloc(1, sizeof(struct ref_lock));
442 lock->lock_fd = -1;
443
444 ref = resolve_ref(ref, lock->old_sha1, mustexist);
445 if (!ref) {
446 int last_errno = errno;
447 error("unable to resolve reference %s: %s",
448 orig_ref, strerror(errno));
449 unlock_ref(lock);
450 errno = last_errno;
451 return NULL;
452 }
453 lock->lk = xcalloc(1, sizeof(struct lock_file));
454
455 lock->ref_name = xstrdup(ref);
456 lock->log_file = xstrdup(git_path("logs/%s", ref));
457 ref_file = git_path(ref);
458 lock->force_write = lstat(ref_file, &st) && errno == ENOENT;
459
460 if (safe_create_leading_directories(ref_file))
461 die("unable to create directory for %s", ref_file);
462 lock->lock_fd = hold_lock_file_for_update(lock->lk, ref_file, 1);
463
464 return old_sha1 ? verify_lock(lock, old_sha1, mustexist) : lock;
465 }
466
467 struct ref_lock *lock_ref_sha1(const char *ref,
468 const unsigned char *old_sha1, int mustexist)
469 {
470 char refpath[PATH_MAX];
471 if (check_ref_format(ref))
472 return NULL;
473 strcpy(refpath, mkpath("refs/%s", ref));
474 return lock_ref_sha1_basic(refpath, strlen(refpath),
475 old_sha1, mustexist);
476 }
477
478 struct ref_lock *lock_any_ref_for_update(const char *ref,
479 const unsigned char *old_sha1, int mustexist)
480 {
481 return lock_ref_sha1_basic(ref, strlen(ref), old_sha1, mustexist);
482 }
483
484 void unlock_ref(struct ref_lock *lock)
485 {
486 if (lock->lock_fd >= 0) {
487 close(lock->lock_fd);
488 /* Do not free lock->lk -- atexit() still looks at them */
489 if (lock->lk)
490 rollback_lock_file(lock->lk);
491 }
492 free(lock->ref_name);
493 free(lock->log_file);
494 free(lock);
495 }
496
497 static int log_ref_write(struct ref_lock *lock,
498 const unsigned char *sha1, const char *msg)
499 {
500 int logfd, written, oflags = O_APPEND | O_WRONLY;
501 unsigned maxlen, len;
502 char *logrec;
503 const char *committer;
504
505 if (log_all_ref_updates) {
506 if (safe_create_leading_directories(lock->log_file) < 0)
507 return error("unable to create directory for %s",
508 lock->log_file);
509 oflags |= O_CREAT;
510 }
511
512 logfd = open(lock->log_file, oflags, 0666);
513 if (logfd < 0) {
514 if (!log_all_ref_updates && errno == ENOENT)
515 return 0;
516 return error("Unable to append to %s: %s",
517 lock->log_file, strerror(errno));
518 }
519
520 committer = git_committer_info(1);
521 if (msg) {
522 maxlen = strlen(committer) + strlen(msg) + 2*40 + 5;
523 logrec = xmalloc(maxlen);
524 len = snprintf(logrec, maxlen, "%s %s %s\t%s\n",
525 sha1_to_hex(lock->old_sha1),
526 sha1_to_hex(sha1),
527 committer,
528 msg);
529 }
530 else {
531 maxlen = strlen(committer) + 2*40 + 4;
532 logrec = xmalloc(maxlen);
533 len = snprintf(logrec, maxlen, "%s %s %s\n",
534 sha1_to_hex(lock->old_sha1),
535 sha1_to_hex(sha1),
536 committer);
537 }
538 written = len <= maxlen ? write(logfd, logrec, len) : -1;
539 free(logrec);
540 close(logfd);
541 if (written != len)
542 return error("Unable to append to %s", lock->log_file);
543 return 0;
544 }
545
546 int write_ref_sha1(struct ref_lock *lock,
547 const unsigned char *sha1, const char *logmsg)
548 {
549 static char term = '\n';
550
551 if (!lock)
552 return -1;
553 if (!lock->force_write && !hashcmp(lock->old_sha1, sha1)) {
554 unlock_ref(lock);
555 return 0;
556 }
557 if (write(lock->lock_fd, sha1_to_hex(sha1), 40) != 40 ||
558 write(lock->lock_fd, &term, 1) != 1
559 || close(lock->lock_fd) < 0) {
560 error("Couldn't write %s", lock->lk->filename);
561 unlock_ref(lock);
562 return -1;
563 }
564 if (log_ref_write(lock, sha1, logmsg) < 0) {
565 unlock_ref(lock);
566 return -1;
567 }
568 if (commit_lock_file(lock->lk)) {
569 error("Couldn't set %s", lock->ref_name);
570 unlock_ref(lock);
571 return -1;
572 }
573 lock->lock_fd = -1;
574 unlock_ref(lock);
575 return 0;
576 }
577
578 int read_ref_at(const char *ref, unsigned long at_time, unsigned char *sha1)
579 {
580 const char *logfile, *logdata, *logend, *rec, *lastgt, *lastrec;
581 char *tz_c;
582 int logfd, tz;
583 struct stat st;
584 unsigned long date;
585 unsigned char logged_sha1[20];
586
587 logfile = git_path("logs/%s", ref);
588 logfd = open(logfile, O_RDONLY, 0);
589 if (logfd < 0)
590 die("Unable to read log %s: %s", logfile, strerror(errno));
591 fstat(logfd, &st);
592 if (!st.st_size)
593 die("Log %s is empty.", logfile);
594 logdata = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, logfd, 0);
595 close(logfd);
596
597 lastrec = NULL;
598 rec = logend = logdata + st.st_size;
599 while (logdata < rec) {
600 if (logdata < rec && *(rec-1) == '\n')
601 rec--;
602 lastgt = NULL;
603 while (logdata < rec && *(rec-1) != '\n') {
604 rec--;
605 if (*rec == '>')
606 lastgt = rec;
607 }
608 if (!lastgt)
609 die("Log %s is corrupt.", logfile);
610 date = strtoul(lastgt + 1, &tz_c, 10);
611 if (date <= at_time) {
612 if (lastrec) {
613 if (get_sha1_hex(lastrec, logged_sha1))
614 die("Log %s is corrupt.", logfile);
615 if (get_sha1_hex(rec + 41, sha1))
616 die("Log %s is corrupt.", logfile);
617 if (hashcmp(logged_sha1, sha1)) {
618 tz = strtoul(tz_c, NULL, 10);
619 fprintf(stderr,
620 "warning: Log %s has gap after %s.\n",
621 logfile, show_rfc2822_date(date, tz));
622 }
623 }
624 else if (date == at_time) {
625 if (get_sha1_hex(rec + 41, sha1))
626 die("Log %s is corrupt.", logfile);
627 }
628 else {
629 if (get_sha1_hex(rec + 41, logged_sha1))
630 die("Log %s is corrupt.", logfile);
631 if (hashcmp(logged_sha1, sha1)) {
632 tz = strtoul(tz_c, NULL, 10);
633 fprintf(stderr,
634 "warning: Log %s unexpectedly ended on %s.\n",
635 logfile, show_rfc2822_date(date, tz));
636 }
637 }
638 munmap((void*)logdata, st.st_size);
639 return 0;
640 }
641 lastrec = rec;
642 }
643
644 rec = logdata;
645 while (rec < logend && *rec != '>' && *rec != '\n')
646 rec++;
647 if (rec == logend || *rec == '\n')
648 die("Log %s is corrupt.", logfile);
649 date = strtoul(rec + 1, &tz_c, 10);
650 tz = strtoul(tz_c, NULL, 10);
651 if (get_sha1_hex(logdata, sha1))
652 die("Log %s is corrupt.", logfile);
653 munmap((void*)logdata, st.st_size);
654 fprintf(stderr, "warning: Log %s only goes back to %s.\n",
655 logfile, show_rfc2822_date(date, tz));
656 return 0;
657 }