| -rw-r--r-- | cache.c | 16 |
1 files changed, 13 insertions, 3 deletions
@@ -207,134 +207,144 @@ unsigned long hash_str(const char *str) { unsigned long h = FNV_OFFSET; unsigned char *s = (unsigned char *)str; if (!s) return h; while(*s) { h *= FNV_PRIME; h ^= *s++; } return h; } static int process_slot(struct cache_slot *slot) { int err; err = open_slot(slot); if (!err && slot->match) { if (is_expired(slot)) { if (!lock_slot(slot)) { /* If the cachefile has been replaced between * `open_slot` and `lock_slot`, we'll just * serve the stale content from the original * cachefile. This way we avoid pruning the * newly generated slot. The same code-path * is chosen if fill_slot() fails for some * reason. * * TODO? check if the new slot contains the * same key as the old one, since we would * prefer to serve the newest content. * This will require us to open yet another * file-descriptor and read and compare the * key from the new file, so for now we're * lazy and just ignore the new file. */ if (is_modified(slot) || fill_slot(slot)) { unlock_slot(slot, 0); close_lock(slot); } else { close_slot(slot); unlock_slot(slot, 1); slot->cache_fd = slot->lock_fd; } } } - print_slot(slot); + if ((err = print_slot(slot)) != 0) { + cache_log("[cgit] error printing cache %s: %s (%d)\n", + slot->cache_name, + strerror(err), + err); + } close_slot(slot); - return 0; + return err; } /* If the cache slot does not exist (or its key doesn't match the * current key), lets try to create a new cache slot for this * request. If this fails (for whatever reason), lets just generate * the content without caching it and fool the caller to belive * everything worked out (but print a warning on stdout). */ close_slot(slot); if ((err = lock_slot(slot)) != 0) { cache_log("[cgit] Unable to lock slot %s: %s (%d)\n", slot->lock_name, strerror(err), err); slot->fn(slot->cbdata); return 0; } if ((err = fill_slot(slot)) != 0) { cache_log("[cgit] Unable to fill slot %s: %s (%d)\n", slot->lock_name, strerror(err), err); unlock_slot(slot, 0); close_lock(slot); slot->fn(slot->cbdata); return 0; } // We've got a valid cache slot in the lock file, which // is about to replace the old cache slot. But if we // release the lockfile and then try to open the new cache // slot, we might get a race condition with a concurrent // writer for the same cache slot (with a different key). // Lets avoid such a race by just printing the content of // the lock file. slot->cache_fd = slot->lock_fd; unlock_slot(slot, 1); - err = print_slot(slot); + if ((err = print_slot(slot)) != 0) { + cache_log("[cgit] error printing cache %s: %s (%d)\n", + slot->cache_name, + strerror(err), + err); + } close_slot(slot); return err; } /* Print cached content to stdout, generate the content if necessary. */ int cache_process(int size, const char *path, const char *key, int ttl, cache_fill_fn fn, void *cbdata) { unsigned long hash; int len, i; char filename[1024]; char lockname[1024 + 5]; /* 5 = ".lock" */ struct cache_slot slot; /* If the cache is disabled, just generate the content */ if (size <= 0) { fn(cbdata); return 0; } /* Verify input, calculate filenames */ if (!path) { cache_log("[cgit] Cache path not specified, caching is disabled\n"); fn(cbdata); return 0; } len = strlen(path); if (len > sizeof(filename) - 10) { /* 10 = "/01234567\0" */ cache_log("[cgit] Cache path too long, caching is disabled: %s\n", path); fn(cbdata); return 0; } if (!key) key = ""; hash = hash_str(key) % size; strcpy(filename, path); if (filename[len - 1] != '/') filename[len++] = '/'; for(i = 0; i < 8; i++) { sprintf(filename + len++, "%x", (unsigned char)(hash & 0xf)); hash >>= 4; } filename[len] = '\0'; strcpy(lockname, filename); strcpy(lockname + len, ".lock"); slot.fn = fn; |