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2006-12-12cache_lock: do xstrdup/free on lockfileLars Hjemli1-1/+2
Since fmt() uses 8 alternating static buffers, and cache_lock might call cache_create_dirs() multiple times, which in turn might call fmt() twice, after four iterations lockfile would be overwritten by a cachedirectory path. In worst case, this could cause the cachedirectory to be unlinked and replaced by a cachefile. Fix: use xstrdup() on the result from fmt() before assigning to lockfile, and call free(lockfile) before exit. Signed-off-by: Lars Hjemli <hjemli@gmail.com>
2006-12-11Don't truncate valid cachefilesLars Hjemli1-0/+5
An embarrassing thinko in cgit_check_cache() would truncate valid cachefiles in the following situation: 1) process A notices a missing/expired cachefile 2) process B gets scheduled, locks, fills and unlocks the cachefile 3) process A gets scheduled, locks the cachefile, notices that the cachefile now exist/is not expired anymore, and continues to overwrite it with an empty lockfile. Thanks to Linus for noticing (again). Signed-off-by: Lars Hjemli <hjemli@gmail.com>
2006-12-11Avoid infinite loops in caching layerLars Hjemli1-13/+22
Add a global variable, cgit_max_lock_attemps, to avoid the possibility of infinite loops when failing to acquire a lockfile. This could happen on broken setups or under crazy server load. Incidentally, this also fixes a lurking bug in cache_lock() where an uninitialized returnvalue was used. Signed-off-by: Lars Hjemli <hjemli@gmail.com>
2006-12-11Fix cache algorithm loopholeLars Hjemli1-1/+5
This closes the door for unneccessary calls to cgit_fill_cache(). Noticed by Linus. Signed-off-by: Lars Hjemli <hjemli@gmail.com>
2006-12-10Add license file and copyright noticesLars Hjemli1-0/+8
Signed-off-by: Lars Hjemli <hjemli@gmail.com>
2006-12-10Add caching infrastructureLars Hjemli1-0/+86
This enables internal caching of page output. Page requests are split into four groups: 1) repo listing (front page) 2) repo summary 3) repo pages w/symbolic references in query string 4) repo pages w/constant sha1's in query string Each group has a TTL specified in minutes. When a page is requested, a cached filename is stat(2)'ed and st_mtime is compared to time(2). If TTL has expired (or the file didn't exist), the cached file is regenerated. When generating a cached file, locking is used to avoid parallell processing of the request. If multiple processes tries to aquire the same lock, the ones who fail to get the lock serves the (expired) cached file. If the cached file don't exist, the process instead calls sched_yield(2) before restarting the request processing. Signed-off-by: Lars Hjemli <hjemli@gmail.com>