cgit

commit f5069d88dff7a7ed2f4665904b03e906cca75a7c

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 */