Add callback data to for_each_ref() family.
[gitweb.git] / refs.c
diff --git a/refs.c b/refs.c
index 0f3491f871bd692151b42307b833e633b041e948..85564f0dc70ffd298daf3a9f2bb84801b6564911 100644 (file)
--- a/refs.c
+++ b/refs.c
 
 #include <errno.h>
 
+struct ref_list {
+       struct ref_list *next;
+       unsigned char sha1[20];
+       char name[FLEX_ARRAY];
+};
+
+static const char *parse_ref_line(char *line, unsigned char *sha1)
+{
+       /*
+        * 42: the answer to everything.
+        *
+        * In this case, it happens to be the answer to
+        *  40 (length of sha1 hex representation)
+        *  +1 (space in between hex and name)
+        *  +1 (newline at the end of the line)
+        */
+       int len = strlen(line) - 42;
+
+       if (len <= 0)
+               return NULL;
+       if (get_sha1_hex(line, sha1) < 0)
+               return NULL;
+       if (!isspace(line[40]))
+               return NULL;
+       line += 41;
+       if (isspace(*line))
+               return NULL;
+       if (line[len] != '\n')
+               return NULL;
+       line[len] = 0;
+       return line;
+}
+
+static struct ref_list *add_ref(const char *name, const unsigned char *sha1, struct ref_list *list)
+{
+       int len;
+       struct ref_list **p = &list, *entry;
+
+       /* Find the place to insert the ref into.. */
+       while ((entry = *p) != NULL) {
+               int cmp = strcmp(entry->name, name);
+               if (cmp > 0)
+                       break;
+
+               /* Same as existing entry? */
+               if (!cmp)
+                       return list;
+               p = &entry->next;
+       }
+
+       /* Allocate it and add it in.. */
+       len = strlen(name) + 1;
+       entry = xmalloc(sizeof(struct ref_list) + len);
+       hashcpy(entry->sha1, sha1);
+       memcpy(entry->name, name, len);
+       entry->next = *p;
+       *p = entry;
+       return list;
+}
+
+static struct ref_list *get_packed_refs(void)
+{
+       static int did_refs = 0;
+       static struct ref_list *refs = NULL;
+
+       if (!did_refs) {
+               FILE *f = fopen(git_path("packed-refs"), "r");
+               if (f) {
+                       struct ref_list *list = NULL;
+                       char refline[PATH_MAX];
+                       while (fgets(refline, sizeof(refline), f)) {
+                               unsigned char sha1[20];
+                               const char *name = parse_ref_line(refline, sha1);
+                               if (!name)
+                                       continue;
+                               list = add_ref(name, sha1, list);
+                       }
+                       fclose(f);
+                       refs = list;
+               }
+               did_refs = 1;
+       }
+       return refs;
+}
+
+static struct ref_list *get_ref_dir(const char *base, struct ref_list *list)
+{
+       DIR *dir = opendir(git_path("%s", base));
+
+       if (dir) {
+               struct dirent *de;
+               int baselen = strlen(base);
+               char *ref = xmalloc(baselen + 257);
+
+               memcpy(ref, base, baselen);
+               if (baselen && base[baselen-1] != '/')
+                       ref[baselen++] = '/';
+
+               while ((de = readdir(dir)) != NULL) {
+                       unsigned char sha1[20];
+                       struct stat st;
+                       int namelen;
+
+                       if (de->d_name[0] == '.')
+                               continue;
+                       namelen = strlen(de->d_name);
+                       if (namelen > 255)
+                               continue;
+                       if (has_extension(de->d_name, ".lock"))
+                               continue;
+                       memcpy(ref + baselen, de->d_name, namelen+1);
+                       if (stat(git_path("%s", ref), &st) < 0)
+                               continue;
+                       if (S_ISDIR(st.st_mode)) {
+                               list = get_ref_dir(ref, list);
+                               continue;
+                       }
+                       if (read_ref(ref, sha1) < 0) {
+                               error("%s points nowhere!", ref);
+                               continue;
+                       }
+                       list = add_ref(ref, sha1, list);
+               }
+               free(ref);
+               closedir(dir);
+       }
+       return list;
+}
+
+static struct ref_list *get_loose_refs(void)
+{
+       static int did_refs = 0;
+       static struct ref_list *refs = NULL;
+
+       if (!did_refs) {
+               refs = get_ref_dir("refs", NULL);
+               did_refs = 1;
+       }
+       return refs;
+}
+
 /* We allow "recursive" symbolic refs. Only within reason, though */
 #define MAXDEPTH 5
 
-const char *resolve_ref(const char *path, unsigned char *sha1, int reading)
+const char *resolve_ref(const char *ref, unsigned char *sha1, int reading)
 {
        int depth = MAXDEPTH, len;
        char buffer[256];
+       static char ref_buffer[256];
 
        for (;;) {
+               const char *path = git_path("%s", ref);
                struct stat st;
                char *buf;
                int fd;
@@ -27,17 +170,27 @@ const char *resolve_ref(const char *path, unsigned char *sha1, int reading)
                 * reading.
                 */
                if (lstat(path, &st) < 0) {
+                       struct ref_list *list = get_packed_refs();
+                       while (list) {
+                               if (!strcmp(ref, list->name)) {
+                                       hashcpy(sha1, list->sha1);
+                                       return ref;
+                               }
+                               list = list->next;
+                       }
                        if (reading || errno != ENOENT)
                                return NULL;
-                       memset(sha1, 0, 20);
-                       return path;
+                       hashclr(sha1);
+                       return ref;
                }
 
                /* Follow "normalized" - ie "refs/.." symlinks by hand */
                if (S_ISLNK(st.st_mode)) {
                        len = readlink(path, buffer, sizeof(buffer)-1);
                        if (len >= 5 && !memcmp("refs/", buffer, 5)) {
-                               path = git_path("%.*s", len, buffer);
+                               buffer[len] = 0;
+                               strcpy(ref_buffer, buffer);
+                               ref = ref_buffer;
                                continue;
                        }
                }
@@ -62,19 +215,22 @@ const char *resolve_ref(const char *path, unsigned char *sha1, int reading)
                while (len && isspace(*buf))
                        buf++, len--;
                while (len && isspace(buf[len-1]))
-                       buf[--len] = 0;
-               path = git_path("%.*s", len, buf);
+                       len--;
+               buf[len] = 0;
+               memcpy(ref_buffer, buf, len + 1);
+               ref = ref_buffer;
        }
        if (len < 40 || get_sha1_hex(buffer, sha1))
                return NULL;
-       return path;
+       return ref;
 }
 
-int create_symref(const char *git_HEAD, const char *refs_heads_master)
+int create_symref(const char *ref_target, const char *refs_heads_master)
 {
        const char *lockpath;
        char ref[1000];
        int fd, len, written;
+       const char *git_HEAD = git_path("%s", ref_target);
 
 #ifndef NO_SYMLINK_HEAD
        if (prefer_symlink_refs) {
@@ -104,213 +260,104 @@ int create_symref(const char *git_HEAD, const char *refs_heads_master)
                error("Unable to create %s", git_HEAD);
                return -3;
        }
+       if (adjust_shared_perm(git_HEAD)) {
+               unlink(lockpath);
+               error("Unable to fix permissions on %s", lockpath);
+               return -4;
+       }
        return 0;
 }
 
-int read_ref(const char *filename, unsigned char *sha1)
+int read_ref(const char *ref, unsigned char *sha1)
 {
-       if (resolve_ref(filename, sha1, 1))
+       if (resolve_ref(ref, sha1, 1))
                return 0;
        return -1;
 }
 
-static int do_for_each_ref(const char *base, int (*fn)(const char *path, const unsigned char *sha1), int trim)
+static int do_for_each_ref(const char *base, each_ref_fn fn, int trim, void *cb_data)
 {
-       int retval = 0;
-       DIR *dir = opendir(git_path("%s", base));
-
-       if (dir) {
-               struct dirent *de;
-               int baselen = strlen(base);
-               char *path = xmalloc(baselen + 257);
-
-               if (!strncmp(base, "./", 2)) {
-                       base += 2;
-                       baselen -= 2;
+       int retval;
+       struct ref_list *packed = get_packed_refs();
+       struct ref_list *loose = get_loose_refs();
+
+       while (packed && loose) {
+               struct ref_list *entry;
+               int cmp = strcmp(packed->name, loose->name);
+               if (!cmp) {
+                       packed = packed->next;
+                       continue;
                }
-               memcpy(path, base, baselen);
-               if (baselen && base[baselen-1] != '/')
-                       path[baselen++] = '/';
-
-               while ((de = readdir(dir)) != NULL) {
-                       unsigned char sha1[20];
-                       struct stat st;
-                       int namelen;
+               if (cmp > 0) {
+                       entry = loose;
+                       loose = loose->next;
+               } else {
+                       entry = packed;
+                       packed = packed->next;
+               }
+               if (strncmp(base, entry->name, trim))
+                       continue;
+               if (is_null_sha1(entry->sha1))
+                       continue;
+               if (!has_sha1_file(entry->sha1)) {
+                       error("%s does not point to a valid object!", entry->name);
+                       continue;
+               }
+               retval = fn(entry->name + trim, entry->sha1, cb_data);
+               if (retval)
+                       return retval;
+       }
 
-                       if (de->d_name[0] == '.')
-                               continue;
-                       namelen = strlen(de->d_name);
-                       if (namelen > 255)
-                               continue;
-                       memcpy(path + baselen, de->d_name, namelen+1);
-                       if (stat(git_path("%s", path), &st) < 0)
-                               continue;
-                       if (S_ISDIR(st.st_mode)) {
-                               retval = do_for_each_ref(path, fn, trim);
-                               if (retval)
-                                       break;
-                               continue;
-                       }
-                       if (read_ref(git_path("%s", path), sha1) < 0) {
-                               error("%s points nowhere!", path);
-                               continue;
-                       }
-                       if (!has_sha1_file(sha1)) {
-                               error("%s does not point to a valid "
-                                     "commit object!", path);
-                               continue;
-                       }
-                       retval = fn(path + trim, sha1);
+       packed = packed ? packed : loose;
+       while (packed) {
+               if (!strncmp(base, packed->name, trim)) {
+                       retval = fn(packed->name + trim, packed->sha1, cb_data);
                        if (retval)
-                               break;
+                               return retval;
                }
-               free(path);
-               closedir(dir);
+               packed = packed->next;
        }
-       return retval;
+       return 0;
 }
 
-int head_ref(int (*fn)(const char *path, const unsigned char *sha1))
+int head_ref(each_ref_fn fn, void *cb_data)
 {
        unsigned char sha1[20];
-       if (!read_ref(git_path("HEAD"), sha1))
-               return fn("HEAD", sha1);
+       if (!read_ref("HEAD", sha1))
+               return fn("HEAD", sha1, cb_data);
        return 0;
 }
 
-int for_each_ref(int (*fn)(const char *path, const unsigned char *sha1))
+int for_each_ref(each_ref_fn fn, void *cb_data)
 {
-       return do_for_each_ref("refs", fn, 0);
+       return do_for_each_ref("refs/", fn, 0, cb_data);
 }
 
-int for_each_tag_ref(int (*fn)(const char *path, const unsigned char *sha1))
+int for_each_tag_ref(each_ref_fn fn, void *cb_data)
 {
-       return do_for_each_ref("refs/tags", fn, 10);
+       return do_for_each_ref("refs/tags/", fn, 10, cb_data);
 }
 
-int for_each_branch_ref(int (*fn)(const char *path, const unsigned char *sha1))
+int for_each_branch_ref(each_ref_fn fn, void *cb_data)
 {
-       return do_for_each_ref("refs/heads", fn, 11);
+       return do_for_each_ref("refs/heads/", fn, 11, cb_data);
 }
 
-int for_each_remote_ref(int (*fn)(const char *path, const unsigned char *sha1))
+int for_each_remote_ref(each_ref_fn fn, void *cb_data)
 {
-       return do_for_each_ref("refs/remotes", fn, 13);
-}
-
-static char *ref_file_name(const char *ref)
-{
-       char *base = get_refs_directory();
-       int baselen = strlen(base);
-       int reflen = strlen(ref);
-       char *ret = xmalloc(baselen + 2 + reflen);
-       sprintf(ret, "%s/%s", base, ref);
-       return ret;
-}
-
-static char *ref_lock_file_name(const char *ref)
-{
-       char *base = get_refs_directory();
-       int baselen = strlen(base);
-       int reflen = strlen(ref);
-       char *ret = xmalloc(baselen + 7 + reflen);
-       sprintf(ret, "%s/%s.lock", base, ref);
-       return ret;
+       return do_for_each_ref("refs/remotes/", fn, 13, cb_data);
 }
 
+/* NEEDSWORK: This is only used by ssh-upload and it should go; the
+ * caller should do resolve_ref or read_ref like everybody else.  Or
+ * maybe everybody else should use get_ref_sha1() instead of doing
+ * read_ref().
+ */
 int get_ref_sha1(const char *ref, unsigned char *sha1)
 {
        if (check_ref_format(ref))
                return -1;
-       return read_ref(git_path("refs/%s", ref), sha1);
-}
-
-static int lock_ref_file(const char *filename, const char *lock_filename,
-                        const unsigned char *old_sha1)
-{
-       int fd = open(lock_filename, O_WRONLY | O_CREAT | O_EXCL, 0666);
-       unsigned char current_sha1[20];
-       int retval;
-       if (fd < 0) {
-               return error("Couldn't open lock file for %s: %s",
-                            filename, strerror(errno));
-       }
-       retval = read_ref(filename, current_sha1);
-       if (old_sha1) {
-               if (retval) {
-                       close(fd);
-                       unlink(lock_filename);
-                       return error("Could not read the current value of %s",
-                                    filename);
-               }
-               if (memcmp(current_sha1, old_sha1, 20)) {
-                       close(fd);
-                       unlink(lock_filename);
-                       error("The current value of %s is %s",
-                             filename, sha1_to_hex(current_sha1));
-                       return error("Expected %s",
-                                    sha1_to_hex(old_sha1));
-               }
-       } else {
-               if (!retval) {
-                       close(fd);
-                       unlink(lock_filename);
-                       return error("Unexpectedly found a value of %s for %s",
-                                    sha1_to_hex(current_sha1), filename);
-               }
-       }
-       return fd;
-}
-
-int lock_ref_sha1(const char *ref, const unsigned char *old_sha1)
-{
-       char *filename;
-       char *lock_filename;
-       int retval;
-       if (check_ref_format(ref))
-               return -1;
-       filename = ref_file_name(ref);
-       lock_filename = ref_lock_file_name(ref);
-       retval = lock_ref_file(filename, lock_filename, old_sha1);
-       free(filename);
-       free(lock_filename);
-       return retval;
-}
-
-static int write_ref_file(const char *filename,
-                         const char *lock_filename, int fd,
-                         const unsigned char *sha1)
-{
-       char *hex = sha1_to_hex(sha1);
-       char term = '\n';
-       if (write(fd, hex, 40) < 40 ||
-           write(fd, &term, 1) < 1) {
-               error("Couldn't write %s", filename);
-               close(fd);
-               return -1;
-       }
-       close(fd);
-       rename(lock_filename, filename);
-       return 0;
-}
-
-int write_ref_sha1(const char *ref, int fd, const unsigned char *sha1)
-{
-       char *filename;
-       char *lock_filename;
-       int retval;
-       if (fd < 0)
-               return -1;
-       if (check_ref_format(ref))
-               return -1;
-       filename = ref_file_name(ref);
-       lock_filename = ref_lock_file_name(ref);
-       if (safe_create_leading_directories(filename))
-               die("unable to create leading directory for %s", filename);
-       retval = write_ref_file(filename, lock_filename, fd, sha1);
-       free(filename);
-       free(lock_filename);
-       return retval;
+       return read_ref(mkpath("refs/%s", ref), sha1);
 }
 
 /*
@@ -365,25 +412,246 @@ int check_ref_format(const char *ref)
        }
 }
 
-int write_ref_sha1_unlocked(const char *ref, const unsigned char *sha1)
+static struct ref_lock *verify_lock(struct ref_lock *lock,
+       const unsigned char *old_sha1, int mustexist)
 {
-       char *filename;
-       char *lock_filename;
-       int fd;
-       int retval;
+       if (!resolve_ref(lock->ref_name, lock->old_sha1, mustexist)) {
+               error("Can't verify ref %s", lock->ref_name);
+               unlock_ref(lock);
+               return NULL;
+       }
+       if (hashcmp(lock->old_sha1, old_sha1)) {
+               error("Ref %s is at %s but expected %s", lock->ref_name,
+                       sha1_to_hex(lock->old_sha1), sha1_to_hex(old_sha1));
+               unlock_ref(lock);
+               return NULL;
+       }
+       return lock;
+}
+
+static struct ref_lock *lock_ref_sha1_basic(const char *ref,
+       int plen,
+       const unsigned char *old_sha1, int mustexist)
+{
+       char *ref_file;
+       const char *orig_ref = ref;
+       struct ref_lock *lock;
+       struct stat st;
+
+       lock = xcalloc(1, sizeof(struct ref_lock));
+       lock->lock_fd = -1;
+
+       ref = resolve_ref(ref, lock->old_sha1, mustexist);
+       if (!ref) {
+               int last_errno = errno;
+               error("unable to resolve reference %s: %s",
+                       orig_ref, strerror(errno));
+               unlock_ref(lock);
+               errno = last_errno;
+               return NULL;
+       }
+       lock->lk = xcalloc(1, sizeof(struct lock_file));
+
+       lock->ref_name = xstrdup(ref);
+       lock->log_file = xstrdup(git_path("logs/%s", ref));
+       ref_file = git_path(ref);
+       lock->force_write = lstat(ref_file, &st) && errno == ENOENT;
+
+       if (safe_create_leading_directories(ref_file))
+               die("unable to create directory for %s", ref_file);
+       lock->lock_fd = hold_lock_file_for_update(lock->lk, ref_file, 1);
+
+       return old_sha1 ? verify_lock(lock, old_sha1, mustexist) : lock;
+}
+
+struct ref_lock *lock_ref_sha1(const char *ref,
+       const unsigned char *old_sha1, int mustexist)
+{
+       char refpath[PATH_MAX];
        if (check_ref_format(ref))
+               return NULL;
+       strcpy(refpath, mkpath("refs/%s", ref));
+       return lock_ref_sha1_basic(refpath, strlen(refpath),
+               old_sha1, mustexist);
+}
+
+struct ref_lock *lock_any_ref_for_update(const char *ref,
+       const unsigned char *old_sha1, int mustexist)
+{
+       return lock_ref_sha1_basic(ref, strlen(ref), old_sha1, mustexist);
+}
+
+void unlock_ref(struct ref_lock *lock)
+{
+       if (lock->lock_fd >= 0) {
+               close(lock->lock_fd);
+               /* Do not free lock->lk -- atexit() still looks at them */
+               if (lock->lk)
+                       rollback_lock_file(lock->lk);
+       }
+       free(lock->ref_name);
+       free(lock->log_file);
+       free(lock);
+}
+
+static int log_ref_write(struct ref_lock *lock,
+       const unsigned char *sha1, const char *msg)
+{
+       int logfd, written, oflags = O_APPEND | O_WRONLY;
+       unsigned maxlen, len;
+       char *logrec;
+       const char *committer;
+
+       if (log_all_ref_updates) {
+               if (safe_create_leading_directories(lock->log_file) < 0)
+                       return error("unable to create directory for %s",
+                               lock->log_file);
+               oflags |= O_CREAT;
+       }
+
+       logfd = open(lock->log_file, oflags, 0666);
+       if (logfd < 0) {
+               if (!log_all_ref_updates && errno == ENOENT)
+                       return 0;
+               return error("Unable to append to %s: %s",
+                       lock->log_file, strerror(errno));
+       }
+
+       committer = git_committer_info(1);
+       if (msg) {
+               maxlen = strlen(committer) + strlen(msg) + 2*40 + 5;
+               logrec = xmalloc(maxlen);
+               len = snprintf(logrec, maxlen, "%s %s %s\t%s\n",
+                       sha1_to_hex(lock->old_sha1),
+                       sha1_to_hex(sha1),
+                       committer,
+                       msg);
+       }
+       else {
+               maxlen = strlen(committer) + 2*40 + 4;
+               logrec = xmalloc(maxlen);
+               len = snprintf(logrec, maxlen, "%s %s %s\n",
+                       sha1_to_hex(lock->old_sha1),
+                       sha1_to_hex(sha1),
+                       committer);
+       }
+       written = len <= maxlen ? write(logfd, logrec, len) : -1;
+       free(logrec);
+       close(logfd);
+       if (written != len)
+               return error("Unable to append to %s", lock->log_file);
+       return 0;
+}
+
+int write_ref_sha1(struct ref_lock *lock,
+       const unsigned char *sha1, const char *logmsg)
+{
+       static char term = '\n';
+
+       if (!lock)
+               return -1;
+       if (!lock->force_write && !hashcmp(lock->old_sha1, sha1)) {
+               unlock_ref(lock);
+               return 0;
+       }
+       if (write(lock->lock_fd, sha1_to_hex(sha1), 40) != 40 ||
+           write(lock->lock_fd, &term, 1) != 1
+               || close(lock->lock_fd) < 0) {
+               error("Couldn't write %s", lock->lk->filename);
+               unlock_ref(lock);
                return -1;
-       filename = ref_file_name(ref);
-       lock_filename = ref_lock_file_name(ref);
-       if (safe_create_leading_directories(filename))
-               die("unable to create leading directory for %s", filename);
-       fd = open(lock_filename, O_WRONLY | O_CREAT | O_EXCL, 0666);
-       if (fd < 0) {
-               error("Writing %s", lock_filename);
-               perror("Open");
        }
-       retval = write_ref_file(filename, lock_filename, fd, sha1);
-       free(filename);
-       free(lock_filename);
-       return retval;
+       if (log_ref_write(lock, sha1, logmsg) < 0) {
+               unlock_ref(lock);
+               return -1;
+       }
+       if (commit_lock_file(lock->lk)) {
+               error("Couldn't set %s", lock->ref_name);
+               unlock_ref(lock);
+               return -1;
+       }
+       lock->lock_fd = -1;
+       unlock_ref(lock);
+       return 0;
+}
+
+int read_ref_at(const char *ref, unsigned long at_time, unsigned char *sha1)
+{
+       const char *logfile, *logdata, *logend, *rec, *lastgt, *lastrec;
+       char *tz_c;
+       int logfd, tz;
+       struct stat st;
+       unsigned long date;
+       unsigned char logged_sha1[20];
+
+       logfile = git_path("logs/%s", ref);
+       logfd = open(logfile, O_RDONLY, 0);
+       if (logfd < 0)
+               die("Unable to read log %s: %s", logfile, strerror(errno));
+       fstat(logfd, &st);
+       if (!st.st_size)
+               die("Log %s is empty.", logfile);
+       logdata = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, logfd, 0);
+       close(logfd);
+
+       lastrec = NULL;
+       rec = logend = logdata + st.st_size;
+       while (logdata < rec) {
+               if (logdata < rec && *(rec-1) == '\n')
+                       rec--;
+               lastgt = NULL;
+               while (logdata < rec && *(rec-1) != '\n') {
+                       rec--;
+                       if (*rec == '>')
+                               lastgt = rec;
+               }
+               if (!lastgt)
+                       die("Log %s is corrupt.", logfile);
+               date = strtoul(lastgt + 1, &tz_c, 10);
+               if (date <= at_time) {
+                       if (lastrec) {
+                               if (get_sha1_hex(lastrec, logged_sha1))
+                                       die("Log %s is corrupt.", logfile);
+                               if (get_sha1_hex(rec + 41, sha1))
+                                       die("Log %s is corrupt.", logfile);
+                               if (hashcmp(logged_sha1, sha1)) {
+                                       tz = strtoul(tz_c, NULL, 10);
+                                       fprintf(stderr,
+                                               "warning: Log %s has gap after %s.\n",
+                                               logfile, show_rfc2822_date(date, tz));
+                               }
+                       }
+                       else if (date == at_time) {
+                               if (get_sha1_hex(rec + 41, sha1))
+                                       die("Log %s is corrupt.", logfile);
+                       }
+                       else {
+                               if (get_sha1_hex(rec + 41, logged_sha1))
+                                       die("Log %s is corrupt.", logfile);
+                               if (hashcmp(logged_sha1, sha1)) {
+                                       tz = strtoul(tz_c, NULL, 10);
+                                       fprintf(stderr,
+                                               "warning: Log %s unexpectedly ended on %s.\n",
+                                               logfile, show_rfc2822_date(date, tz));
+                               }
+                       }
+                       munmap((void*)logdata, st.st_size);
+                       return 0;
+               }
+               lastrec = rec;
+       }
+
+       rec = logdata;
+       while (rec < logend && *rec != '>' && *rec != '\n')
+               rec++;
+       if (rec == logend || *rec == '\n')
+               die("Log %s is corrupt.", logfile);
+       date = strtoul(rec + 1, &tz_c, 10);
+       tz = strtoul(tz_c, NULL, 10);
+       if (get_sha1_hex(logdata, sha1))
+               die("Log %s is corrupt.", logfile);
+       munmap((void*)logdata, st.st_size);
+       fprintf(stderr, "warning: Log %s only goes back to %s.\n",
+               logfile, show_rfc2822_date(date, tz));
+       return 0;
 }