1#include "refs.h"
2#include "cache.h"
3#include <errno.h>
5struct ref_list {
7 struct ref_list *next;
8 unsigned char flag; /* ISSYMREF? ISPACKED? */
9 unsigned char sha1[20];
10 char name[FLEX_ARRAY];
11};
12static const char *parse_ref_line(char *line, unsigned char *sha1)
14{
15 /*
16 * 42: the answer to everything.
17 *
18 * In this case, it happens to be the answer to
19 * 40 (length of sha1 hex representation)
20 * +1 (space in between hex and name)
21 * +1 (newline at the end of the line)
22 */
23 int len = strlen(line) - 42;
24 if (len <= 0)
26 return NULL;
27 if (get_sha1_hex(line, sha1) < 0)
28 return NULL;
29 if (!isspace(line[40]))
30 return NULL;
31 line += 41;
32 if (isspace(*line))
33 return NULL;
34 if (line[len] != '\n')
35 return NULL;
36 line[len] = 0;
37 return line;
38}
39static struct ref_list *add_ref(const char *name, const unsigned char *sha1,
41 int flag, struct ref_list *list)
42{
43 int len;
44 struct ref_list **p = &list, *entry;
45 /* Find the place to insert the ref into.. */
47 while ((entry = *p) != NULL) {
48 int cmp = strcmp(entry->name, name);
49 if (cmp > 0)
50 break;
51 /* Same as existing entry? */
53 if (!cmp)
54 return list;
55 p = &entry->next;
56 }
57 /* Allocate it and add it in.. */
59 len = strlen(name) + 1;
60 entry = xmalloc(sizeof(struct ref_list) + len);
61 hashcpy(entry->sha1, sha1);
62 memcpy(entry->name, name, len);
63 entry->flag = flag;
64 entry->next = *p;
65 *p = entry;
66 return list;
67}
68/*
70 * Future: need to be in "struct repository"
71 * when doing a full libification.
72 */
73struct cached_refs {
74 char did_loose;
75 char did_packed;
76 struct ref_list *loose;
77 struct ref_list *packed;
78} cached_refs;
79static void free_ref_list(struct ref_list *list)
81{
82 struct ref_list *next;
83 for ( ; list; list = next) {
84 next = list->next;
85 free(list);
86 }
87}
88static void invalidate_cached_refs(void)
90{
91 struct cached_refs *ca = &cached_refs;
92 if (ca->did_loose && ca->loose)
94 free_ref_list(ca->loose);
95 if (ca->did_packed && ca->packed)
96 free_ref_list(ca->packed);
97 ca->loose = ca->packed = NULL;
98 ca->did_loose = ca->did_packed = 0;
99}
100static struct ref_list *get_packed_refs(void)
102{
103 if (!cached_refs.did_packed) {
104 struct ref_list *refs = NULL;
105 FILE *f = fopen(git_path("packed-refs"), "r");
106 if (f) {
107 struct ref_list *list = NULL;
108 char refline[PATH_MAX];
109 while (fgets(refline, sizeof(refline), f)) {
110 unsigned char sha1[20];
111 const char *name = parse_ref_line(refline, sha1);
112 if (!name)
113 continue;
114 list = add_ref(name, sha1, REF_ISPACKED, list);
115 }
116 fclose(f);
117 refs = list;
118 }
119 cached_refs.packed = refs;
120 cached_refs.did_packed = 1;
121 }
122 return cached_refs.packed;
123}
124static struct ref_list *get_ref_dir(const char *base, struct ref_list *list)
126{
127 DIR *dir = opendir(git_path("%s", base));
128 if (dir) {
130 struct dirent *de;
131 int baselen = strlen(base);
132 char *ref = xmalloc(baselen + 257);
133 memcpy(ref, base, baselen);
135 if (baselen && base[baselen-1] != '/')
136 ref[baselen++] = '/';
137 while ((de = readdir(dir)) != NULL) {
139 unsigned char sha1[20];
140 struct stat st;
141 int flag;
142 int namelen;
143 if (de->d_name[0] == '.')
145 continue;
146 namelen = strlen(de->d_name);
147 if (namelen > 255)
148 continue;
149 if (has_extension(de->d_name, ".lock"))
150 continue;
151 memcpy(ref + baselen, de->d_name, namelen+1);
152 if (stat(git_path("%s", ref), &st) < 0)
153 continue;
154 if (S_ISDIR(st.st_mode)) {
155 list = get_ref_dir(ref, list);
156 continue;
157 }
158 if (!resolve_ref(ref, sha1, 1, &flag)) {
159 error("%s points nowhere!", ref);
160 continue;
161 }
162 list = add_ref(ref, sha1, flag, list);
163 }
164 free(ref);
165 closedir(dir);
166 }
167 return list;
168}
169static struct ref_list *get_loose_refs(void)
171{
172 if (!cached_refs.did_loose) {
173 cached_refs.loose = get_ref_dir("refs", NULL);
174 cached_refs.did_loose = 1;
175 }
176 return cached_refs.loose;
177}
178/* We allow "recursive" symbolic refs. Only within reason, though */
180#define MAXDEPTH 5
181const char *resolve_ref(const char *ref, unsigned char *sha1, int reading, int *flag)
183{
184 int depth = MAXDEPTH, len;
185 char buffer[256];
186 static char ref_buffer[256];
187 if (flag)
189 *flag = 0;
190 for (;;) {
192 const char *path = git_path("%s", ref);
193 struct stat st;
194 char *buf;
195 int fd;
196 if (--depth < 0)
198 return NULL;
199 /* Special case: non-existing file.
201 * Not having the refs/heads/new-branch is OK
202 * if we are writing into it, so is .git/HEAD
203 * that points at refs/heads/master still to be
204 * born. It is NOT OK if we are resolving for
205 * reading.
206 */
207 if (lstat(path, &st) < 0) {
208 struct ref_list *list = get_packed_refs();
209 while (list) {
210 if (!strcmp(ref, list->name)) {
211 hashcpy(sha1, list->sha1);
212 if (flag)
213 *flag |= REF_ISPACKED;
214 return ref;
215 }
216 list = list->next;
217 }
218 if (reading || errno != ENOENT)
219 return NULL;
220 hashclr(sha1);
221 return ref;
222 }
223 /* Follow "normalized" - ie "refs/.." symlinks by hand */
225 if (S_ISLNK(st.st_mode)) {
226 len = readlink(path, buffer, sizeof(buffer)-1);
227 if (len >= 5 && !memcmp("refs/", buffer, 5)) {
228 buffer[len] = 0;
229 strcpy(ref_buffer, buffer);
230 ref = ref_buffer;
231 if (flag)
232 *flag |= REF_ISSYMREF;
233 continue;
234 }
235 }
236 /* Is it a directory? */
238 if (S_ISDIR(st.st_mode)) {
239 errno = EISDIR;
240 return NULL;
241 }
242 /*
244 * Anything else, just open it and try to use it as
245 * a ref
246 */
247 fd = open(path, O_RDONLY);
248 if (fd < 0)
249 return NULL;
250 len = read(fd, buffer, sizeof(buffer)-1);
251 close(fd);
252 /*
254 * Is it a symbolic ref?
255 */
256 if (len < 4 || memcmp("ref:", buffer, 4))
257 break;
258 buf = buffer + 4;
259 len -= 4;
260 while (len && isspace(*buf))
261 buf++, len--;
262 while (len && isspace(buf[len-1]))
263 len--;
264 buf[len] = 0;
265 memcpy(ref_buffer, buf, len + 1);
266 ref = ref_buffer;
267 if (flag)
268 *flag |= REF_ISSYMREF;
269 }
270 if (len < 40 || get_sha1_hex(buffer, sha1))
271 return NULL;
272 return ref;
273}
274int create_symref(const char *ref_target, const char *refs_heads_master)
276{
277 const char *lockpath;
278 char ref[1000];
279 int fd, len, written;
280 const char *git_HEAD = git_path("%s", ref_target);
281#ifndef NO_SYMLINK_HEAD
283 if (prefer_symlink_refs) {
284 unlink(git_HEAD);
285 if (!symlink(refs_heads_master, git_HEAD))
286 return 0;
287 fprintf(stderr, "no symlink - falling back to symbolic ref\n");
288 }
289#endif
290 len = snprintf(ref, sizeof(ref), "ref: %s\n", refs_heads_master);
292 if (sizeof(ref) <= len) {
293 error("refname too long: %s", refs_heads_master);
294 return -1;
295 }
296 lockpath = mkpath("%s.lock", git_HEAD);
297 fd = open(lockpath, O_CREAT | O_EXCL | O_WRONLY, 0666);
298 written = write(fd, ref, len);
299 close(fd);
300 if (written != len) {
301 unlink(lockpath);
302 error("Unable to write to %s", lockpath);
303 return -2;
304 }
305 if (rename(lockpath, git_HEAD) < 0) {
306 unlink(lockpath);
307 error("Unable to create %s", git_HEAD);
308 return -3;
309 }
310 if (adjust_shared_perm(git_HEAD)) {
311 unlink(lockpath);
312 error("Unable to fix permissions on %s", lockpath);
313 return -4;
314 }
315 return 0;
316}
317int read_ref(const char *ref, unsigned char *sha1)
319{
320 if (resolve_ref(ref, sha1, 1, NULL))
321 return 0;
322 return -1;
323}
324static int do_for_each_ref(const char *base, each_ref_fn fn, int trim,
326 void *cb_data)
327{
328 int retval;
329 struct ref_list *packed = get_packed_refs();
330 struct ref_list *loose = get_loose_refs();
331 while (packed && loose) {
333 struct ref_list *entry;
334 int cmp = strcmp(packed->name, loose->name);
335 if (!cmp) {
336 packed = packed->next;
337 continue;
338 }
339 if (cmp > 0) {
340 entry = loose;
341 loose = loose->next;
342 } else {
343 entry = packed;
344 packed = packed->next;
345 }
346 if (strncmp(base, entry->name, trim))
347 continue;
348 if (is_null_sha1(entry->sha1))
349 continue;
350 if (!has_sha1_file(entry->sha1)) {
351 error("%s does not point to a valid object!", entry->name);
352 continue;
353 }
354 retval = fn(entry->name + trim, entry->sha1,
355 entry->flag, cb_data);
356 if (retval)
357 return retval;
358 }
359 packed = packed ? packed : loose;
361 while (packed) {
362 if (!strncmp(base, packed->name, trim)) {
363 retval = fn(packed->name + trim, packed->sha1,
364 packed->flag, cb_data);
365 if (retval)
366 return retval;
367 }
368 packed = packed->next;
369 }
370 return 0;
371}
372int head_ref(each_ref_fn fn, void *cb_data)
374{
375 unsigned char sha1[20];
376 int flag;
377 if (resolve_ref("HEAD", sha1, 1, &flag))
379 return fn("HEAD", sha1, flag, cb_data);
380 return 0;
381}
382int for_each_ref(each_ref_fn fn, void *cb_data)
384{
385 return do_for_each_ref("refs/", fn, 0, cb_data);
386}
387int for_each_tag_ref(each_ref_fn fn, void *cb_data)
389{
390 return do_for_each_ref("refs/tags/", fn, 10, cb_data);
391}
392int for_each_branch_ref(each_ref_fn fn, void *cb_data)
394{
395 return do_for_each_ref("refs/heads/", fn, 11, cb_data);
396}
397int for_each_remote_ref(each_ref_fn fn, void *cb_data)
399{
400 return do_for_each_ref("refs/remotes/", fn, 13, cb_data);
401}
402/* NEEDSWORK: This is only used by ssh-upload and it should go; the
404 * caller should do resolve_ref or read_ref like everybody else. Or
405 * maybe everybody else should use get_ref_sha1() instead of doing
406 * read_ref().
407 */
408int get_ref_sha1(const char *ref, unsigned char *sha1)
409{
410 if (check_ref_format(ref))
411 return -1;
412 return read_ref(mkpath("refs/%s", ref), sha1);
413}
414/*
416 * Make sure "ref" is something reasonable to have under ".git/refs/";
417 * We do not like it if:
418 *
419 * - any path component of it begins with ".", or
420 * - it has double dots "..", or
421 * - it has ASCII control character, "~", "^", ":" or SP, anywhere, or
422 * - it ends with a "/".
423 */
424static inline int bad_ref_char(int ch)
426{
427 return (((unsigned) ch) <= ' ' ||
428 ch == '~' || ch == '^' || ch == ':' ||
429 /* 2.13 Pattern Matching Notation */
430 ch == '?' || ch == '*' || ch == '[');
431}
432int check_ref_format(const char *ref)
434{
435 int ch, level;
436 const char *cp = ref;
437 level = 0;
439 while (1) {
440 while ((ch = *cp++) == '/')
441 ; /* tolerate duplicated slashes */
442 if (!ch)
443 return -1; /* should not end with slashes */
444 /* we are at the beginning of the path component */
446 if (ch == '.' || bad_ref_char(ch))
447 return -1;
448 /* scan the rest of the path component */
450 while ((ch = *cp++) != 0) {
451 if (bad_ref_char(ch))
452 return -1;
453 if (ch == '/')
454 break;
455 if (ch == '.' && *cp == '.')
456 return -1;
457 }
458 level++;
459 if (!ch) {
460 if (level < 2)
461 return -1; /* at least of form "heads/blah" */
462 return 0;
463 }
464 }
465}
466static struct ref_lock *verify_lock(struct ref_lock *lock,
468 const unsigned char *old_sha1, int mustexist)
469{
470 if (!resolve_ref(lock->ref_name, lock->old_sha1, mustexist, NULL)) {
471 error("Can't verify ref %s", lock->ref_name);
472 unlock_ref(lock);
473 return NULL;
474 }
475 if (hashcmp(lock->old_sha1, old_sha1)) {
476 error("Ref %s is at %s but expected %s", lock->ref_name,
477 sha1_to_hex(lock->old_sha1), sha1_to_hex(old_sha1));
478 unlock_ref(lock);
479 return NULL;
480 }
481 return lock;
482}
483static int remove_empty_dir_recursive(char *path, int len)
485{
486 DIR *dir = opendir(path);
487 struct dirent *e;
488 int ret = 0;
489 if (!dir)
491 return -1;
492 if (path[len-1] != '/')
493 path[len++] = '/';
494 while ((e = readdir(dir)) != NULL) {
495 struct stat st;
496 int namlen;
497 if ((e->d_name[0] == '.') &&
498 ((e->d_name[1] == 0) ||
499 ((e->d_name[1] == '.') && e->d_name[2] == 0)))
500 continue; /* "." and ".." */
501 namlen = strlen(e->d_name);
503 if ((len + namlen < PATH_MAX) &&
504 strcpy(path + len, e->d_name) &&
505 !lstat(path, &st) &&
506 S_ISDIR(st.st_mode) &&
507 !remove_empty_dir_recursive(path, len + namlen))
508 continue; /* happy */
509 /* path too long, stat fails, or non-directory still exists */
511 ret = -1;
512 break;
513 }
514 closedir(dir);
515 if (!ret) {
516 path[len] = 0;
517 ret = rmdir(path);
518 }
519 return ret;
520}
521static int remove_empty_directories(char *file)
523{
524 /* we want to create a file but there is a directory there;
525 * if that is an empty directory (or a directory that contains
526 * only empty directories), remove them.
527 */
528 char path[PATH_MAX];
529 int len = strlen(file);
530 if (len >= PATH_MAX) /* path too long ;-) */
532 return -1;
533 strcpy(path, file);
534 return remove_empty_dir_recursive(path, len);
535}
536static struct ref_lock *lock_ref_sha1_basic(const char *ref, const unsigned char *old_sha1, int *flag)
538{
539 char *ref_file;
540 const char *orig_ref = ref;
541 struct ref_lock *lock;
542 struct stat st;
543 int last_errno = 0;
544 int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
545 lock = xcalloc(1, sizeof(struct ref_lock));
547 lock->lock_fd = -1;
548 ref = resolve_ref(ref, lock->old_sha1, mustexist, flag);
550 if (!ref && errno == EISDIR) {
551 /* we are trying to lock foo but we used to
552 * have foo/bar which now does not exist;
553 * it is normal for the empty directory 'foo'
554 * to remain.
555 */
556 ref_file = git_path("%s", orig_ref);
557 if (remove_empty_directories(ref_file)) {
558 last_errno = errno;
559 error("there are still refs under '%s'", orig_ref);
560 goto error_return;
561 }
562 ref = resolve_ref(orig_ref, lock->old_sha1, mustexist, flag);
563 }
564 if (!ref) {
565 last_errno = errno;
566 error("unable to resolve reference %s: %s",
567 orig_ref, strerror(errno));
568 goto error_return;
569 }
570 if (is_null_sha1(lock->old_sha1)) {
571 /* The ref did not exist and we are creating it.
572 * Make sure there is no existing ref that is packed
573 * whose name begins with our refname, nor a ref whose
574 * name is a proper prefix of our refname.
575 */
576 int namlen = strlen(ref); /* e.g. 'foo/bar' */
577 struct ref_list *list = get_packed_refs();
578 while (list) {
579 /* list->name could be 'foo' or 'foo/bar/baz' */
580 int len = strlen(list->name);
581 int cmplen = (namlen < len) ? namlen : len;
582 const char *lead = (namlen < len) ? list->name : ref;
583 if (!strncmp(ref, list->name, cmplen) &&
585 lead[cmplen] == '/') {
586 error("'%s' exists; cannot create '%s'",
587 list->name, ref);
588 goto error_return;
589 }
590 list = list->next;
591 }
592 }
593 lock->lk = xcalloc(1, sizeof(struct lock_file));
595 lock->ref_name = xstrdup(ref);
597 lock->log_file = xstrdup(git_path("logs/%s", ref));
598 ref_file = git_path("%s", ref);
599 lock->force_write = lstat(ref_file, &st) && errno == ENOENT;
600 if (safe_create_leading_directories(ref_file)) {
602 last_errno = errno;
603 error("unable to create directory for %s", ref_file);
604 goto error_return;
605 }
606 lock->lock_fd = hold_lock_file_for_update(lock->lk, ref_file, 1);
607 return old_sha1 ? verify_lock(lock, old_sha1, mustexist) : lock;
609 error_return:
611 unlock_ref(lock);
612 errno = last_errno;
613 return NULL;
614}
615struct ref_lock *lock_ref_sha1(const char *ref, const unsigned char *old_sha1)
617{
618 char refpath[PATH_MAX];
619 if (check_ref_format(ref))
620 return NULL;
621 strcpy(refpath, mkpath("refs/%s", ref));
622 return lock_ref_sha1_basic(refpath, old_sha1, NULL);
623}
624struct ref_lock *lock_any_ref_for_update(const char *ref, const unsigned char *old_sha1)
626{
627 return lock_ref_sha1_basic(ref, old_sha1, NULL);
628}
629static struct lock_file packlock;
631static int repack_without_ref(const char *refname)
633{
634 struct ref_list *list, *packed_ref_list;
635 int fd;
636 int found = 0;
637 packed_ref_list = get_packed_refs();
639 for (list = packed_ref_list; list; list = list->next) {
640 if (!strcmp(refname, list->name)) {
641 found = 1;
642 break;
643 }
644 }
645 if (!found)
646 return 0;
647 memset(&packlock, 0, sizeof(packlock));
648 fd = hold_lock_file_for_update(&packlock, git_path("packed-refs"), 0);
649 if (fd < 0)
650 return error("cannot delete '%s' from packed refs", refname);
651 for (list = packed_ref_list; list; list = list->next) {
653 char line[PATH_MAX + 100];
654 int len;
655 if (!strcmp(refname, list->name))
657 continue;
658 len = snprintf(line, sizeof(line), "%s %s\n",
659 sha1_to_hex(list->sha1), list->name);
660 /* this should not happen but just being defensive */
661 if (len > sizeof(line))
662 die("too long a refname '%s'", list->name);
663 write_or_die(fd, line, len);
664 }
665 return commit_lock_file(&packlock);
666}
667int delete_ref(const char *refname, unsigned char *sha1)
669{
670 struct ref_lock *lock;
671 int err, i, ret = 0, flag = 0;
672 lock = lock_ref_sha1_basic(refname, sha1, &flag);
674 if (!lock)
675 return 1;
676 if (!(flag & REF_ISPACKED)) {
677 /* loose */
678 i = strlen(lock->lk->filename) - 5; /* .lock */
679 lock->lk->filename[i] = 0;
680 err = unlink(lock->lk->filename);
681 if (err) {
682 ret = 1;
683 error("unlink(%s) failed: %s",
684 lock->lk->filename, strerror(errno));
685 }
686 lock->lk->filename[i] = '.';
687 }
688 /* removing the loose one could have resurrected an earlier
689 * packed one. Also, if it was not loose we need to repack
690 * without it.
691 */
692 ret |= repack_without_ref(refname);
693 err = unlink(lock->log_file);
695 if (err && errno != ENOENT)
696 fprintf(stderr, "warning: unlink(%s) failed: %s",
697 lock->log_file, strerror(errno));
698 invalidate_cached_refs();
699 unlock_ref(lock);
700 return ret;
701}
702void unlock_ref(struct ref_lock *lock)
704{
705 if (lock->lock_fd >= 0) {
706 close(lock->lock_fd);
707 /* Do not free lock->lk -- atexit() still looks at them */
708 if (lock->lk)
709 rollback_lock_file(lock->lk);
710 }
711 free(lock->ref_name);
712 free(lock->log_file);
713 free(lock);
714}
715static int log_ref_write(struct ref_lock *lock,
717 const unsigned char *sha1, const char *msg)
718{
719 int logfd, written, oflags = O_APPEND | O_WRONLY;
720 unsigned maxlen, len;
721 char *logrec;
722 const char *committer;
723 if (log_all_ref_updates &&
725 !strncmp(lock->ref_name, "refs/heads/", 11)) {
726 if (safe_create_leading_directories(lock->log_file) < 0)
727 return error("unable to create directory for %s",
728 lock->log_file);
729 oflags |= O_CREAT;
730 }
731 logfd = open(lock->log_file, oflags, 0666);
733 if (logfd < 0) {
734 if (!(oflags & O_CREAT) && errno == ENOENT)
735 return 0;
736 if ((oflags & O_CREAT) && errno == EISDIR) {
738 if (remove_empty_directories(lock->log_file)) {
739 return error("There are still logs under '%s'",
740 lock->log_file);
741 }
742 logfd = open(lock->log_file, oflags, 0666);
743 }
744 if (logfd < 0)
746 return error("Unable to append to %s: %s",
747 lock->log_file, strerror(errno));
748 }
749 committer = git_committer_info(1);
751 if (msg) {
752 maxlen = strlen(committer) + strlen(msg) + 2*40 + 5;
753 logrec = xmalloc(maxlen);
754 len = snprintf(logrec, maxlen, "%s %s %s\t%s\n",
755 sha1_to_hex(lock->old_sha1),
756 sha1_to_hex(sha1),
757 committer,
758 msg);
759 }
760 else {
761 maxlen = strlen(committer) + 2*40 + 4;
762 logrec = xmalloc(maxlen);
763 len = snprintf(logrec, maxlen, "%s %s %s\n",
764 sha1_to_hex(lock->old_sha1),
765 sha1_to_hex(sha1),
766 committer);
767 }
768 written = len <= maxlen ? write(logfd, logrec, len) : -1;
769 free(logrec);
770 close(logfd);
771 if (written != len)
772 return error("Unable to append to %s", lock->log_file);
773 return 0;
774}
775int write_ref_sha1(struct ref_lock *lock,
777 const unsigned char *sha1, const char *logmsg)
778{
779 static char term = '\n';
780 if (!lock)
782 return -1;
783 if (!lock->force_write && !hashcmp(lock->old_sha1, sha1)) {
784 unlock_ref(lock);
785 return 0;
786 }
787 if (write(lock->lock_fd, sha1_to_hex(sha1), 40) != 40 ||
788 write(lock->lock_fd, &term, 1) != 1
789 || close(lock->lock_fd) < 0) {
790 error("Couldn't write %s", lock->lk->filename);
791 unlock_ref(lock);
792 return -1;
793 }
794 invalidate_cached_refs();
795 if (log_ref_write(lock, sha1, logmsg) < 0) {
796 unlock_ref(lock);
797 return -1;
798 }
799 if (commit_lock_file(lock->lk)) {
800 error("Couldn't set %s", lock->ref_name);
801 unlock_ref(lock);
802 return -1;
803 }
804 lock->lock_fd = -1;
805 unlock_ref(lock);
806 return 0;
807}
808int read_ref_at(const char *ref, unsigned long at_time, int cnt, unsigned char *sha1)
810{
811 const char *logfile, *logdata, *logend, *rec, *lastgt, *lastrec;
812 char *tz_c;
813 int logfd, tz;
814 struct stat st;
815 unsigned long date;
816 unsigned char logged_sha1[20];
817 logfile = git_path("logs/%s", ref);
819 logfd = open(logfile, O_RDONLY, 0);
820 if (logfd < 0)
821 die("Unable to read log %s: %s", logfile, strerror(errno));
822 fstat(logfd, &st);
823 if (!st.st_size)
824 die("Log %s is empty.", logfile);
825 logdata = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, logfd, 0);
826 close(logfd);
827 lastrec = NULL;
829 rec = logend = logdata + st.st_size;
830 while (logdata < rec) {
831 if (logdata < rec && *(rec-1) == '\n')
832 rec--;
833 lastgt = NULL;
834 while (logdata < rec && *(rec-1) != '\n') {
835 rec--;
836 if (*rec == '>')
837 lastgt = rec;
838 }
839 if (!lastgt)
840 die("Log %s is corrupt.", logfile);
841 date = strtoul(lastgt + 1, &tz_c, 10);
842 if (date <= at_time || cnt == 0) {
843 if (lastrec) {
844 if (get_sha1_hex(lastrec, logged_sha1))
845 die("Log %s is corrupt.", logfile);
846 if (get_sha1_hex(rec + 41, sha1))
847 die("Log %s is corrupt.", logfile);
848 if (hashcmp(logged_sha1, sha1)) {
849 tz = strtoul(tz_c, NULL, 10);
850 fprintf(stderr,
851 "warning: Log %s has gap after %s.\n",
852 logfile, show_rfc2822_date(date, tz));
853 }
854 }
855 else if (date == at_time) {
856 if (get_sha1_hex(rec + 41, sha1))
857 die("Log %s is corrupt.", logfile);
858 }
859 else {
860 if (get_sha1_hex(rec + 41, logged_sha1))
861 die("Log %s is corrupt.", logfile);
862 if (hashcmp(logged_sha1, sha1)) {
863 tz = strtoul(tz_c, NULL, 10);
864 fprintf(stderr,
865 "warning: Log %s unexpectedly ended on %s.\n",
866 logfile, show_rfc2822_date(date, tz));
867 }
868 }
869 munmap((void*)logdata, st.st_size);
870 return 0;
871 }
872 lastrec = rec;
873 if (cnt > 0)
874 cnt--;
875 }
876 rec = logdata;
878 while (rec < logend && *rec != '>' && *rec != '\n')
879 rec++;
880 if (rec == logend || *rec == '\n')
881 die("Log %s is corrupt.", logfile);
882 date = strtoul(rec + 1, &tz_c, 10);
883 tz = strtoul(tz_c, NULL, 10);
884 if (get_sha1_hex(logdata, sha1))
885 die("Log %s is corrupt.", logfile);
886 munmap((void*)logdata, st.st_size);
887 fprintf(stderr, "warning: Log %s only goes back to %s.\n",
888 logfile, show_rfc2822_date(date, tz));
889 return 0;
890}