author | Lars Hjemli <hjemli@gmail.com> | 2006-12-11 21:53:50 (UTC) |
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committer | Lars Hjemli <hjemli@gmail.com> | 2006-12-11 21:53:50 (UTC) |
commit | fbaf1171b4e343929dd43ecac7cd9d1c692b84ec (patch) (unidiff) | |
tree | 40b7007b2e1e85f2e91e052b33555df2e9fb5e14 | |
parent | 44923f8953c66dc9b852316b655ab3b5aec9478e (diff) | |
download | cgit-fbaf1171b4e343929dd43ecac7cd9d1c692b84ec.zip cgit-fbaf1171b4e343929dd43ecac7cd9d1c692b84ec.tar.gz cgit-fbaf1171b4e343929dd43ecac7cd9d1c692b84ec.tar.bz2 |
Don't truncate valid cachefiles
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>
-rw-r--r-- | cache.c | 5 | ||||
-rw-r--r-- | cgit.c | 10 | ||||
-rw-r--r-- | cgit.h | 1 |
3 files changed, 14 insertions, 2 deletions
@@ -98,8 +98,13 @@ int cache_unlock(struct cacheitem *item) | |||
98 | close(item->fd); | 98 | close(item->fd); |
99 | return (rename(fmt("%s.lock", item->name), item->name) == 0); | 99 | return (rename(fmt("%s.lock", item->name), item->name) == 0); |
100 | } | 100 | } |
101 | 101 | ||
102 | int cache_cancel_lock(struct cacheitem *item) | ||
103 | { | ||
104 | return (unlink(fmt("%s.lock", item->name)) == 0); | ||
105 | } | ||
106 | |||
102 | int cache_expired(struct cacheitem *item) | 107 | int cache_expired(struct cacheitem *item) |
103 | { | 108 | { |
104 | if (item->ttl < 0) | 109 | if (item->ttl < 0) |
105 | return 0; | 110 | return 0; |
@@ -60,15 +60,21 @@ static void cgit_check_cache(struct cacheitem *item) | |||
60 | if (!cache_lock(item)) { | 60 | if (!cache_lock(item)) { |
61 | sleep(1); | 61 | sleep(1); |
62 | goto top; | 62 | goto top; |
63 | } | 63 | } |
64 | if (!cache_exist(item)) | 64 | if (!cache_exist(item)) { |
65 | cgit_fill_cache(item); | 65 | cgit_fill_cache(item); |
66 | cache_unlock(item); | 66 | cache_unlock(item); |
67 | } else { | ||
68 | cache_cancel_lock(item); | ||
69 | } | ||
67 | } else if (cache_expired(item) && cache_lock(item)) { | 70 | } else if (cache_expired(item) && cache_lock(item)) { |
68 | if (cache_expired(item)) | 71 | if (cache_expired(item)) { |
69 | cgit_fill_cache(item); | 72 | cgit_fill_cache(item); |
70 | cache_unlock(item); | 73 | cache_unlock(item); |
74 | } else { | ||
75 | cache_cancel_lock(item); | ||
76 | } | ||
71 | } | 77 | } |
72 | } | 78 | } |
73 | 79 | ||
74 | static void cgit_print_cache(struct cacheitem *item) | 80 | static void cgit_print_cache(struct cacheitem *item) |
@@ -65,8 +65,9 @@ extern int cgit_parse_query(char *txt, configfn fn); | |||
65 | 65 | ||
66 | extern void cache_prepare(struct cacheitem *item); | 66 | extern void cache_prepare(struct cacheitem *item); |
67 | extern int cache_lock(struct cacheitem *item); | 67 | extern int cache_lock(struct cacheitem *item); |
68 | extern int cache_unlock(struct cacheitem *item); | 68 | extern int cache_unlock(struct cacheitem *item); |
69 | extern int cache_cancel_lock(struct cacheitem *item); | ||
69 | extern int cache_exist(struct cacheitem *item); | 70 | extern int cache_exist(struct cacheitem *item); |
70 | extern int cache_expired(struct cacheitem *item); | 71 | extern int cache_expired(struct cacheitem *item); |
71 | 72 | ||
72 | extern char *cgit_repourl(const char *reponame); | 73 | extern char *cgit_repourl(const char *reponame); |