Author: Lars Hjemli <hjemli@gmail.com>
Fix cache algorithm loophole This closes the door for unneccessary calls to cgit_fill_cache(). Noticed by Linus. Signed-off-by: Lars Hjemli <hjemli@gmail.com>
cache.c | 6 +++++- cgit.c | 18 +++++++++--------- cgit.h | 3 ++-
diff --git a/cache.c b/cache.c index b034c480e0d9866de93bfa3866abda0cb0bd7df5..0ffa502c119ae33deaac913eabb742679cf4fe18 100644 --- a/cache.c +++ b/cache.c @@ -10,7 +10,7 @@ #include "cgit.h" const int NOLOCK = -1; -int cache_lookup(struct cacheitem *item) +void cache_prepare(struct cacheitem *item) { if (!cgit_query_repo) { item->name = xstrdup(fmt("%s/index.html", cgit_cache_root)); @@ -30,6 +30,10 @@ item->ttl = cgit_cache_static_ttl; else item->ttl = cgit_cache_repo_ttl; } +} + +int cache_exist(struct cacheitem *item) +{ if (stat(item->name, &item->st)) { item->st.st_mtime = 0; return 0; diff --git a/cgit.c b/cgit.c index 110facec5867ad0912da6b41c24758a6c3f798cf..7f14016fb70ecb380ffafaa3e7f9f8d92fb362c5 100644 --- a/cgit.c +++ b/cgit.c @@ -465,20 +465,20 @@ } static void cgit_refresh_cache(struct cacheitem *item) { + cache_prepare(item); top: - if (!cache_lookup(item)) { - if (cache_lock(item)) { - cgit_fill_cache(item); - cache_unlock(item); - } else { + if (!cache_exist(item)) { + if (!cache_lock(item)) { sched_yield(); goto top; } - } else if (cache_expired(item)) { - if (cache_lock(item)) { + if (!cache_exist(item)) + cgit_fill_cache(item); + cache_unlock(item); + } else if (cache_expired(item) && cache_lock(item)) { + if (cache_expired(item)) cgit_fill_cache(item); - cache_unlock(item); - } + cache_unlock(item); } } diff --git a/cgit.h b/cgit.h index 1e084d4cb02f743d2b4c014ce69b9a8cacad491f..3b0994a775492f652359ff45f7342c7787f9dc44 100644 --- a/cgit.h +++ b/cgit.h @@ -56,9 +56,10 @@ extern int cgit_read_config(const char *filename, configfn fn); -extern int cache_lookup(struct cacheitem *item); +extern void cache_prepare(struct cacheitem *item); extern int cache_lock(struct cacheitem *item); extern int cache_unlock(struct cacheitem *item); +extern int cache_exist(struct cacheitem *item); extern int cache_expired(struct cacheitem *item); #endif /* CGIT_H */