Potentially fixes some FD leak if an action on an opened file handle fails
for some reason. There have been some hard to reproduce reports of
git-annex leaking FDs, and this may solve them.
If the file is > 8192 bytes, it's certianly not a symlink file.
And if it contains nuls or newlines or whitespace, it's certianly
not a link to annexed content. But it might be a tarball containing
a git-annex repo.
This hack is only needed on FAT filesystems, so there's no point in doing
it the rest of the time. And it's possible for there to be a false
positive, so it's best to avoid the hack when possible.
On Windows, that means the file could still be open when later code wants
to delete it, which fails. Since we're only reading 8k anyway, just read
it, strictly. However, avoid reading the whole file strictly, so no
getContentsStrict here.
On Windows with Cygwin, checking out a git-annex repo will create symlinks
on disk, so we need to always try to read the symlink, even when
core.symlinks says they're not supported.
This avoids commit churn by the assistant when eg,
replacing a file with a symlink.
But, just as importantly, it prevents the working tree being left with a
deleted file if git-annex, or perhaps the whole system, crashes at the
wrong time.
(It also probably avoids confusing displays in file managers.)
Refactored annex link code into nice clean new library.
Audited and dealt with calls to createSymbolicLink.
Remaining calls are all safe, because:
Annex/Link.hs: ( liftIO $ createSymbolicLink linktarget file
only when core.symlinks=true
Assistant/WebApp/Configurators/Local.hs: createSymbolicLink link link
test if symlinks can be made
Command/Fix.hs: liftIO $ createSymbolicLink link file
command only works in indirect mode
Command/FromKey.hs: liftIO $ createSymbolicLink link file
command only works in indirect mode
Command/Indirect.hs: liftIO $ createSymbolicLink l f
refuses to run if core.symlinks=false
Init.hs: createSymbolicLink f f2
test if symlinks can be made
Remote/Directory.hs: go [file] = catchBoolIO $ createSymbolicLink file f >> return True
fast key linking; catches failure to make symlink and falls back to copy
Remote/Git.hs: liftIO $ catchBoolIO $ createSymbolicLink loc file >> return True
ditto
Upgrade/V1.hs: liftIO $ createSymbolicLink link f
v1 repos could not be on a filesystem w/o symlinks
Audited and dealt with calls to readSymbolicLink.
Remaining calls are all safe, because:
Annex/Link.hs: ( liftIO $ catchMaybeIO $ readSymbolicLink file
only when core.symlinks=true
Assistant/Threads/Watcher.hs: ifM ((==) (Just link) <$> liftIO (catchMaybeIO $ readSymbolicLink file))
code that fixes real symlinks when inotify sees them
It's ok to not fix psdueo-symlinks.
Assistant/Threads/Watcher.hs: mlink <- liftIO (catchMaybeIO $ readSymbolicLink file)
ditto
Command/Fix.hs: stopUnless ((/=) (Just link) <$> liftIO (catchMaybeIO $ readSymbolicLink file)) $ do
command only works in indirect mode
Upgrade/V1.hs: getsymlink = takeFileName <$> readSymbolicLink file
v1 repos could not be on a filesystem w/o symlinks
Audited and dealt with calls to isSymbolicLink.
(Typically used with getSymbolicLinkStatus, but that is just used because
getFileStatus is not as robust; it also works on pseudolinks.)
Remaining calls are all safe, because:
Assistant/Threads/SanityChecker.hs: | isSymbolicLink s -> addsymlink file ms
only handles staging of symlinks that were somehow not staged
(might need to be updated to support pseudolinks, but this is
only a belt-and-suspenders check anyway, and I've never seen the code run)
Command/Add.hs: if isSymbolicLink s || not (isRegularFile s)
avoids adding symlinks to the annex, so not relevant
Command/Indirect.hs: | isSymbolicLink s -> void $ flip whenAnnexed f $
only allowed on systems that support symlinks
Command/Indirect.hs: whenM (liftIO $ not . isSymbolicLink <$> getSymbolicLinkStatus f) $ do
ditto
Seek.hs:notSymlink f = liftIO $ not . isSymbolicLink <$> getSymbolicLinkStatus f
used to find unlocked files, only relevant in indirect mode
Utility/FSEvents.hs: | Files.isSymbolicLink s = runhook addSymlinkHook $ Just s
Utility/FSEvents.hs: | Files.isSymbolicLink s ->
Utility/INotify.hs: | Files.isSymbolicLink s ->
Utility/INotify.hs: checkfiletype Files.isSymbolicLink addSymlinkHook f
Utility/Kqueue.hs: | Files.isSymbolicLink s = callhook addSymlinkHook (Just s) change
all above are lower-level, not relevant
Audited and dealt with calls to isSymLink.
Remaining calls are all safe, because:
Annex/Direct.hs: | isSymLink (getmode item) =
This is looking at git diff-tree objects, not files on disk
Command/Unused.hs: | isSymLink (LsTree.mode l) = do
This is looking at git ls-tree, not file on disk
Utility/FileMode.hs:isSymLink :: FileMode -> Bool
Utility/FileMode.hs:isSymLink = checkMode symbolicLinkMode
low-level
Done!!
