symbolit-ref: fix resolve_ref conversion.
[git/git.git] / refs.c
CommitLineData
95fc7512
DB
1#include "refs.h"
2#include "cache.h"
3
4#include <errno.h>
5
e1e22e37
LT
6struct ref_list {
7 struct ref_list *next;
8 unsigned char sha1[20];
9 char name[FLEX_ARRAY];
10};
11
12static 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;
434cd0cd
LT
31 if (isspace(*line))
32 return NULL;
e1e22e37
LT
33 if (line[len] != '\n')
34 return NULL;
35 line[len] = 0;
36 return line;
37}
38
39static 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
66static 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
91static 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);
ed378ec7 98 char *ref = xmalloc(baselen + 257);
e1e22e37 99
ed378ec7 100 memcpy(ref, base, baselen);
e1e22e37 101 if (baselen && base[baselen-1] != '/')
ed378ec7 102 ref[baselen++] = '/';
e1e22e37
LT
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;
ed378ec7
LT
116 memcpy(ref + baselen, de->d_name, namelen+1);
117 if (stat(git_path("%s", ref), &st) < 0)
e1e22e37
LT
118 continue;
119 if (S_ISDIR(st.st_mode)) {
ed378ec7 120 list = get_ref_dir(ref, list);
e1e22e37
LT
121 continue;
122 }
ed378ec7
LT
123 if (read_ref(ref, sha1) < 0) {
124 error("%s points nowhere!", ref);
e1e22e37
LT
125 continue;
126 }
ed378ec7 127 list = add_ref(ref, sha1, list);
e1e22e37 128 }
ed378ec7 129 free(ref);
e1e22e37
LT
130 closedir(dir);
131 }
132 return list;
133}
134
135static 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
ca8db142
LT
147/* We allow "recursive" symbolic refs. Only within reason, though */
148#define MAXDEPTH 5
149
ed378ec7 150const char *resolve_ref(const char *ref, unsigned char *sha1, int reading)
8a65ff76 151{
a876ed83
JH
152 int depth = MAXDEPTH, len;
153 char buffer[256];
ed378ec7 154 static char ref_buffer[256];
ca8db142 155
a876ed83 156 for (;;) {
ed378ec7 157 const char *path = git_path("%s", ref);
a876ed83
JH
158 struct stat st;
159 char *buf;
160 int fd;
8a65ff76 161
a876ed83
JH
162 if (--depth < 0)
163 return NULL;
ca8db142 164
a876ed83
JH
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) {
434cd0cd
LT
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 }
a876ed83
JH
181 if (reading || errno != ENOENT)
182 return NULL;
e702496e 183 hashclr(sha1);
ed378ec7 184 return ref;
a876ed83 185 }
ca8db142 186
a876ed83
JH
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)) {
ed378ec7
LT
191 buffer[len] = 0;
192 strcpy(ref_buffer, buffer);
193 ref = ref_buffer;
a876ed83
JH
194 continue;
195 }
ca8db142 196 }
a876ed83
JH
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]))
ed378ec7
LT
218 len--;
219 buf[len] = 0;
220 memcpy(ref_buffer, buf, len + 1);
221 ref = ref_buffer;
8a65ff76 222 }
a876ed83
JH
223 if (len < 40 || get_sha1_hex(buffer, sha1))
224 return NULL;
ed378ec7 225 return ref;
a876ed83
JH
226}
227
ed378ec7 228int create_symref(const char *ref_target, const char *refs_heads_master)
8098a178 229{
8098a178
JH
230 const char *lockpath;
231 char ref[1000];
232 int fd, len, written;
ed378ec7 233 const char *git_HEAD = git_path("%s", ref_target);
8098a178 234
9f0bb90d
JH
235#ifndef NO_SYMLINK_HEAD
236 if (prefer_symlink_refs) {
f8348be3
JS
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 }
303958dc
JS
242#endif
243
8098a178
JH
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 }
138086a7
JH
263 if (adjust_shared_perm(git_HEAD)) {
264 unlink(lockpath);
265 error("Unable to fix permissions on %s", lockpath);
266 return -4;
267 }
8098a178 268 return 0;
8098a178
JH
269}
270
ed378ec7 271int read_ref(const char *ref, unsigned char *sha1)
a876ed83 272{
ed378ec7 273 if (resolve_ref(ref, sha1, 1))
a876ed83
JH
274 return 0;
275 return -1;
8a65ff76
LT
276}
277
a62be77f 278static int do_for_each_ref(const char *base, int (*fn)(const char *path, const unsigned char *sha1), int trim)
8a65ff76 279{
e1e22e37
LT
280 int retval;
281 struct ref_list *packed = get_packed_refs();
282 struct ref_list *loose = get_loose_refs();
8a65ff76 283
e1e22e37
LT
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;
6cada6a9 290 }
e1e22e37
LT
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;
b37a562a
LT
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 }
e1e22e37
LT
306 retval = fn(entry->name + trim, entry->sha1);
307 if (retval)
308 return retval;
309 }
8a65ff76 310
e1e22e37
LT
311 packed = packed ? packed : loose;
312 while (packed) {
313 if (!strncmp(base, packed->name, trim)) {
314 retval = fn(packed->name + trim, packed->sha1);
8a65ff76 315 if (retval)
e1e22e37 316 return retval;
8a65ff76 317 }
e1e22e37 318 packed = packed->next;
8a65ff76 319 }
e1e22e37 320 return 0;
8a65ff76
LT
321}
322
723c31fe
LT
323int head_ref(int (*fn)(const char *path, const unsigned char *sha1))
324{
325 unsigned char sha1[20];
ed378ec7 326 if (!read_ref("HEAD", sha1))
99a0a6e0 327 return fn("HEAD", sha1);
2f34ba32 328 return 0;
723c31fe
LT
329}
330
944d8589 331int for_each_ref(int (*fn)(const char *path, const unsigned char *sha1))
8a65ff76 332{
e1e22e37 333 return do_for_each_ref("refs/", fn, 0);
a62be77f
SE
334}
335
336int for_each_tag_ref(int (*fn)(const char *path, const unsigned char *sha1))
337{
e1e22e37 338 return do_for_each_ref("refs/tags/", fn, 10);
a62be77f
SE
339}
340
341int for_each_branch_ref(int (*fn)(const char *path, const unsigned char *sha1))
342{
e1e22e37 343 return do_for_each_ref("refs/heads/", fn, 11);
a62be77f
SE
344}
345
346int for_each_remote_ref(int (*fn)(const char *path, const unsigned char *sha1))
347{
e1e22e37 348 return do_for_each_ref("refs/remotes/", fn, 13);
8a65ff76
LT
349}
350
95fc7512
DB
351int get_ref_sha1(const char *ref, unsigned char *sha1)
352{
95fc7512
DB
353 if (check_ref_format(ref))
354 return -1;
ed378ec7 355 return read_ref(mkpath("refs/%s", ref), sha1);
95fc7512
DB
356}
357
03feddd6
JH
358/*
359 * Make sure "ref" is something reasonable to have under ".git/refs/";
360 * We do not like it if:
361 *
362 * - any path component of it begins with ".", or
363 * - it has double dots "..", or
364 * - it has ASCII control character, "~", "^", ":" or SP, anywhere, or
365 * - it ends with a "/".
366 */
367
368static inline int bad_ref_char(int ch)
369{
370 return (((unsigned) ch) <= ' ' ||
68283999
JH
371 ch == '~' || ch == '^' || ch == ':' ||
372 /* 2.13 Pattern Matching Notation */
373 ch == '?' || ch == '*' || ch == '[');
03feddd6
JH
374}
375
95fc7512
DB
376int check_ref_format(const char *ref)
377{
03feddd6
JH
378 int ch, level;
379 const char *cp = ref;
380
381 level = 0;
382 while (1) {
383 while ((ch = *cp++) == '/')
384 ; /* tolerate duplicated slashes */
385 if (!ch)
386 return -1; /* should not end with slashes */
387
388 /* we are at the beginning of the path component */
389 if (ch == '.' || bad_ref_char(ch))
390 return -1;
391
392 /* scan the rest of the path component */
393 while ((ch = *cp++) != 0) {
394 if (bad_ref_char(ch))
395 return -1;
396 if (ch == '/')
397 break;
398 if (ch == '.' && *cp == '.')
399 return -1;
400 }
401 level++;
402 if (!ch) {
403 if (level < 2)
404 return -1; /* at least of form "heads/blah" */
405 return 0;
406 }
407 }
95fc7512
DB
408}
409
e5f38ec3 410static struct ref_lock *verify_lock(struct ref_lock *lock,
4bd18c43
SP
411 const unsigned char *old_sha1, int mustexist)
412{
434cd0cd
LT
413 if (!resolve_ref(lock->ref_name, lock->old_sha1, mustexist)) {
414 error("Can't verify ref %s", lock->ref_name);
4bd18c43
SP
415 unlock_ref(lock);
416 return NULL;
417 }
a89fccd2 418 if (hashcmp(lock->old_sha1, old_sha1)) {
434cd0cd 419 error("Ref %s is at %s but expected %s", lock->ref_name,
4bd18c43
SP
420 sha1_to_hex(lock->old_sha1), sha1_to_hex(old_sha1));
421 unlock_ref(lock);
422 return NULL;
423 }
424 return lock;
425}
426
ed378ec7 427static struct ref_lock *lock_ref_sha1_basic(const char *ref,
4bd18c43
SP
428 int plen,
429 const unsigned char *old_sha1, int mustexist)
430{
434cd0cd 431 char *ref_file;
ed378ec7 432 const char *orig_ref = ref;
4bd18c43 433 struct ref_lock *lock;
732232a1 434 struct stat st;
4bd18c43
SP
435
436 lock = xcalloc(1, sizeof(struct ref_lock));
437 lock->lock_fd = -1;
438
ed378ec7
LT
439 ref = resolve_ref(ref, lock->old_sha1, mustexist);
440 if (!ref) {
818f477c
SP
441 int last_errno = errno;
442 error("unable to resolve reference %s: %s",
ed378ec7 443 orig_ref, strerror(errno));
4bd18c43 444 unlock_ref(lock);
818f477c 445 errno = last_errno;
4bd18c43
SP
446 return NULL;
447 }
c33d5174 448 lock->lk = xcalloc(1, sizeof(struct lock_file));
4bd18c43 449
434cd0cd 450 lock->ref_name = xstrdup(ref);
ed378ec7 451 lock->log_file = xstrdup(git_path("logs/%s", ref));
434cd0cd
LT
452 ref_file = git_path(ref);
453 lock->force_write = lstat(ref_file, &st) && errno == ENOENT;
4bd18c43 454
434cd0cd
LT
455 if (safe_create_leading_directories(ref_file))
456 die("unable to create directory for %s", ref_file);
457 lock->lock_fd = hold_lock_file_for_update(lock->lk, ref_file, 1);
4bd18c43
SP
458
459 return old_sha1 ? verify_lock(lock, old_sha1, mustexist) : lock;
460}
461
e5f38ec3 462struct ref_lock *lock_ref_sha1(const char *ref,
4bd18c43 463 const unsigned char *old_sha1, int mustexist)
95fc7512 464{
53cce84c 465 char refpath[PATH_MAX];
95fc7512 466 if (check_ref_format(ref))
4bd18c43 467 return NULL;
53cce84c
PB
468 strcpy(refpath, mkpath("refs/%s", ref));
469 return lock_ref_sha1_basic(refpath, strlen(refpath),
470 old_sha1, mustexist);
4bd18c43
SP
471}
472
e5f38ec3 473struct ref_lock *lock_any_ref_for_update(const char *ref,
4bd18c43
SP
474 const unsigned char *old_sha1, int mustexist)
475{
ed378ec7 476 return lock_ref_sha1_basic(ref, strlen(ref), old_sha1, mustexist);
4bd18c43
SP
477}
478
e5f38ec3 479void unlock_ref(struct ref_lock *lock)
4bd18c43
SP
480{
481 if (lock->lock_fd >= 0) {
482 close(lock->lock_fd);
c33d5174
JH
483 /* Do not free lock->lk -- atexit() still looks at them */
484 if (lock->lk)
485 rollback_lock_file(lock->lk);
4bd18c43 486 }
434cd0cd 487 free(lock->ref_name);
4cac42b1 488 free(lock->log_file);
4bd18c43
SP
489 free(lock);
490}
491
6de08ae6
SP
492static int log_ref_write(struct ref_lock *lock,
493 const unsigned char *sha1, const char *msg)
494{
495 int logfd, written, oflags = O_APPEND | O_WRONLY;
496 unsigned maxlen, len;
497 char *logrec;
ff4c8485 498 const char *committer;
6de08ae6
SP
499
500 if (log_all_ref_updates) {
501 if (safe_create_leading_directories(lock->log_file) < 0)
502 return error("unable to create directory for %s",
503 lock->log_file);
504 oflags |= O_CREAT;
505 }
506
507 logfd = open(lock->log_file, oflags, 0666);
508 if (logfd < 0) {
509 if (!log_all_ref_updates && errno == ENOENT)
510 return 0;
511 return error("Unable to append to %s: %s",
512 lock->log_file, strerror(errno));
513 }
514
ff4c8485 515 committer = git_committer_info(1);
6de08ae6 516 if (msg) {
ff4c8485 517 maxlen = strlen(committer) + strlen(msg) + 2*40 + 5;
6de08ae6
SP
518 logrec = xmalloc(maxlen);
519 len = snprintf(logrec, maxlen, "%s %s %s\t%s\n",
520 sha1_to_hex(lock->old_sha1),
521 sha1_to_hex(sha1),
ff4c8485 522 committer,
6de08ae6 523 msg);
e5f38ec3
JH
524 }
525 else {
ff4c8485 526 maxlen = strlen(committer) + 2*40 + 4;
6de08ae6
SP
527 logrec = xmalloc(maxlen);
528 len = snprintf(logrec, maxlen, "%s %s %s\n",
529 sha1_to_hex(lock->old_sha1),
530 sha1_to_hex(sha1),
ff4c8485 531 committer);
6de08ae6
SP
532 }
533 written = len <= maxlen ? write(logfd, logrec, len) : -1;
534 free(logrec);
535 close(logfd);
536 if (written != len)
537 return error("Unable to append to %s", lock->log_file);
538 return 0;
539}
540
4bd18c43
SP
541int write_ref_sha1(struct ref_lock *lock,
542 const unsigned char *sha1, const char *logmsg)
543{
544 static char term = '\n';
545
546 if (!lock)
95fc7512 547 return -1;
a89fccd2 548 if (!lock->force_write && !hashcmp(lock->old_sha1, sha1)) {
4bd18c43
SP
549 unlock_ref(lock);
550 return 0;
95fc7512 551 }
4bd18c43
SP
552 if (write(lock->lock_fd, sha1_to_hex(sha1), 40) != 40 ||
553 write(lock->lock_fd, &term, 1) != 1
554 || close(lock->lock_fd) < 0) {
c33d5174 555 error("Couldn't write %s", lock->lk->filename);
4bd18c43
SP
556 unlock_ref(lock);
557 return -1;
558 }
6de08ae6
SP
559 if (log_ref_write(lock, sha1, logmsg) < 0) {
560 unlock_ref(lock);
561 return -1;
562 }
c33d5174 563 if (commit_lock_file(lock->lk)) {
434cd0cd 564 error("Couldn't set %s", lock->ref_name);
4bd18c43
SP
565 unlock_ref(lock);
566 return -1;
567 }
568 lock->lock_fd = -1;
569 unlock_ref(lock);
570 return 0;
95fc7512 571}
d556fae2
SP
572
573int read_ref_at(const char *ref, unsigned long at_time, unsigned char *sha1)
574{
e5229042 575 const char *logfile, *logdata, *logend, *rec, *lastgt, *lastrec;
d556fae2
SP
576 char *tz_c;
577 int logfd, tz;
578 struct stat st;
579 unsigned long date;
e5229042 580 unsigned char logged_sha1[20];
d556fae2
SP
581
582 logfile = git_path("logs/%s", ref);
583 logfd = open(logfile, O_RDONLY, 0);
584 if (logfd < 0)
585 die("Unable to read log %s: %s", logfile, strerror(errno));
586 fstat(logfd, &st);
587 if (!st.st_size)
588 die("Log %s is empty.", logfile);
589 logdata = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, logfd, 0);
590 close(logfd);
591
e5229042 592 lastrec = NULL;
d556fae2
SP
593 rec = logend = logdata + st.st_size;
594 while (logdata < rec) {
595 if (logdata < rec && *(rec-1) == '\n')
596 rec--;
e5229042
SP
597 lastgt = NULL;
598 while (logdata < rec && *(rec-1) != '\n') {
d556fae2 599 rec--;
e5229042
SP
600 if (*rec == '>')
601 lastgt = rec;
602 }
603 if (!lastgt)
d556fae2 604 die("Log %s is corrupt.", logfile);
e5229042 605 date = strtoul(lastgt + 1, &tz_c, 10);
d556fae2 606 if (date <= at_time) {
e5229042
SP
607 if (lastrec) {
608 if (get_sha1_hex(lastrec, logged_sha1))
609 die("Log %s is corrupt.", logfile);
610 if (get_sha1_hex(rec + 41, sha1))
611 die("Log %s is corrupt.", logfile);
a89fccd2 612 if (hashcmp(logged_sha1, sha1)) {
e5229042
SP
613 tz = strtoul(tz_c, NULL, 10);
614 fprintf(stderr,
615 "warning: Log %s has gap after %s.\n",
616 logfile, show_rfc2822_date(date, tz));
617 }
e5f38ec3
JH
618 }
619 else if (date == at_time) {
e5229042
SP
620 if (get_sha1_hex(rec + 41, sha1))
621 die("Log %s is corrupt.", logfile);
e5f38ec3
JH
622 }
623 else {
e5229042
SP
624 if (get_sha1_hex(rec + 41, logged_sha1))
625 die("Log %s is corrupt.", logfile);
a89fccd2 626 if (hashcmp(logged_sha1, sha1)) {
e5229042
SP
627 tz = strtoul(tz_c, NULL, 10);
628 fprintf(stderr,
629 "warning: Log %s unexpectedly ended on %s.\n",
630 logfile, show_rfc2822_date(date, tz));
631 }
632 }
d556fae2
SP
633 munmap((void*)logdata, st.st_size);
634 return 0;
635 }
e5229042 636 lastrec = rec;
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637 }
638
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639 rec = logdata;
640 while (rec < logend && *rec != '>' && *rec != '\n')
641 rec++;
642 if (rec == logend || *rec == '\n')
d556fae2 643 die("Log %s is corrupt.", logfile);
e5229042 644 date = strtoul(rec + 1, &tz_c, 10);
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645 tz = strtoul(tz_c, NULL, 10);
646 if (get_sha1_hex(logdata, sha1))
647 die("Log %s is corrupt.", logfile);
648 munmap((void*)logdata, st.st_size);
649 fprintf(stderr, "warning: Log %s only goes back to %s.\n",
650 logfile, show_rfc2822_date(date, tz));
651 return 0;
652}