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authorGravatar Joey Hess <joey@kitenet.net>2013-10-05 15:01:49 -0400
committerGravatar Joey Hess <joey@kitenet.net>2013-10-05 15:01:49 -0400
commit9f1e2760c60294311c08b5fb8e3a49c773ad89aa (patch)
treec9640e4dece4f84cfec669bfc8035a3c63b7e9bc /Backend
parentf9c3d7562f1ddda3adb8aa892fd40584e9b48ac0 (diff)
Better sanitization of problem characters when generating URL and WORM keys.
FAT has a lot of characters it does not allow in filenames, like ? and * It's probably the worst offender, but other filesystems also have limitiations. In 2011, I made keyFile escape : to handle FAT, but missed the other characters. It also turns out that when I did that, I was also living dangerously; any existing keys that contained a : had their object location change. Oops. So, adding new characters to escape to keyFile is out. Well, it would be possible to make keyFile behave differently on a per-filesystem basis, but this would be a real nightmare to get right. Consider that a rsync special remote uses keyFile to determine the filenames to use, and we don't know the underlying filesystem on the rsync server.. Instead, I have gone for a solution that is backwards compatable and simple. Its only downside is that already generated URL and WORM keys might not be able to be stored on FAT or some other filesystem that dislikes a character used in the key. (In this case, the user can just migrate the problem keys to a checksumming backend. If this became a big problem, fsck could be made to detect these and suggest a migration.) Going forward, new keys that are created will escape all characters that are likely to cause problems. And if some filesystem comes along that's even worse than FAT (seems unlikely, but here it is 2013, and people are still using FAT!), additional characters can be added to the set that are escaped without difficulty. (Also, made WORM limit the part of the filename that is embedded in the key, to deal with filesystem filename length limits. This could have already been a problem, but is more likely now, since the escaping of the filename can make it longer.) This commit was sponsored by Ian Downes
Diffstat (limited to 'Backend')
-rw-r--r--Backend/URL.hs17
-rw-r--r--Backend/Utilities.hs25
-rw-r--r--Backend/WORM.hs14
3 files changed, 38 insertions, 18 deletions
diff --git a/Backend/URL.hs b/Backend/URL.hs
index ace578a24..a8161c98d 100644
--- a/Backend/URL.hs
+++ b/Backend/URL.hs
@@ -10,11 +10,10 @@ module Backend.URL (
fromUrl
) where
-import Data.Hash.MD5
-
import Common.Annex
import Types.Backend
import Types.Key
+import Backend.Utilities
backends :: [Backend]
backends = [backend]
@@ -27,18 +26,12 @@ backend = Backend
, canUpgradeKey = Nothing
}
-{- When it's not too long, use the full url as the key name.
- - If the url is too long, it's truncated at half the filename length
- - limit, and the md5 of the url is prepended to ensure a unique key. -}
+{- Every unique url has a corresponding key. -}
fromUrl :: String -> Maybe Integer -> Annex Key
fromUrl url size = do
- limit <- liftIO . fileNameLengthLimit =<< fromRepo gitAnnexDir
- let truncurl = truncateFilePath (limit `div` 2) url
- let key = if url == truncurl
- then url
- else truncurl ++ "-" ++ md5s (Str url)
+ n <- genKeyName url
return $ stubKey
- { keyName = key
+ { keyName = n
, keyBackendName = "URL"
, keySize = size
- }
+ }
diff --git a/Backend/Utilities.hs b/Backend/Utilities.hs
new file mode 100644
index 000000000..24dbfd6d9
--- /dev/null
+++ b/Backend/Utilities.hs
@@ -0,0 +1,25 @@
+{- git-annex backend utilities
+ -
+ - Copyright 2012 Joey Hess <joey@kitenet.net>
+ -
+ - Licensed under the GNU GPL version 3 or higher.
+ -}
+
+module Backend.Utilities where
+
+import Data.Hash.MD5
+
+import Common.Annex
+
+{- Generates a keyName from an input string. Takes care of sanitizing it.
+ - If it's not too long, the full string is used as the keyName.
+ - Otherwise, it's truncated at half the filename length limit, and its
+ - md5 is prepended to ensure a unique key. -}
+genKeyName :: String -> Annex String
+genKeyName s = do
+ limit <- liftIO . fileNameLengthLimit =<< fromRepo gitAnnexDir
+ let s' = preSanitizeKeyName s
+ let truncs = truncateFilePath (limit `div` 2) s'
+ return $ if s' == truncs
+ then s'
+ else truncs ++ "-" ++ md5s (Str s)
diff --git a/Backend/WORM.hs b/Backend/WORM.hs
index 3471eedc1..60db42f56 100644
--- a/Backend/WORM.hs
+++ b/Backend/WORM.hs
@@ -11,6 +11,7 @@ import Common.Annex
import Types.Backend
import Types.Key
import Types.KeySource
+import Backend.Utilities
backends :: [Backend]
backends = [backend]
@@ -33,9 +34,10 @@ backend = Backend
keyValue :: KeySource -> Annex (Maybe Key)
keyValue source = do
stat <- liftIO $ getFileStatus $ contentLocation source
- return $ Just Key {
- keyName = takeFileName $ keyFilename source,
- keyBackendName = name backend,
- keySize = Just $ fromIntegral $ fileSize stat,
- keyMtime = Just $ modificationTime stat
- }
+ n <- genKeyName $ keyFilename source
+ return $ Just Key
+ { keyName = n
+ , keyBackendName = name backend
+ , keySize = Just $ fromIntegral $ fileSize stat
+ , keyMtime = Just $ modificationTime stat
+ }