git-annex/CmdLine/GitAnnexShell/Checks.hs
Joey Hess d2576e5f1a
git-annex-shell: accept uuid of remote that proxying is enabled for
For NotifyChanges and also for the fallthrough case where
git-annex-shell passes a command off to git-shell, proxying is currently
ignored. So every remote that is accessed via a proxy will be treated as
the same git repository.

Every other command listed in cmdsMap will need to check if
Annex.proxyremote is set, and if so handle the proxying appropriately.
Probably only P2PStdio will need to support proxying. For now,
everything else refuses to work when proxying.

The part of that I don't like is that there's the possibility a command
later gets added to the list that doesn't check proxying.

When proxying is not enabled, it's important that git-annex-shell not
leak information that it would not have exposed before. Such as the
names or uuids of remotes.

I decided that, in the case where a repository used to have proxying
enabled, but no longer supports any proxies, it's ok to give the user a
clear error message indicating that proxying is not configured, rather
than a confusing uuid mismatch message.

Similarly, if a repository has proxying enabled, but not for the
requested repository, give a clear error message.

A tricky thing here is how to handle the case where there is more than
one remote, with proxying enabled, with the specified uuid. One way to
handle that would be to plumb the proxyRemoteName all the way through
from the remote git-annex to git-annex-shell, eg as a field, and use
only a remote with the same name. That would be very intrusive though.

Instead, I decided to let the proxy pick which remote it uses to access
a given Remote. And so it picks the least expensive one.
The client after all doesn't necessarily know any details about the
proxy's configuration. This does mean though, that if the least
expensive remote is not accessible, but another remote would have
worked, an access via the proxy will fail.
2024-06-10 12:44:35 -04:00

93 lines
2.5 KiB
Haskell

{- git-annex-shell checks
-
- Copyright 2012-2024 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU AGPL version 3 or higher.
-}
module CmdLine.GitAnnexShell.Checks where
import Annex.Common
import Command
import qualified Annex
import Annex.Init
import Utility.UserInfo
import Utility.Env
limitedEnv :: String
limitedEnv = "GIT_ANNEX_SHELL_LIMITED"
checkNotLimited :: IO ()
checkNotLimited = checkEnv limitedEnv
readOnlyEnv :: String
readOnlyEnv = "GIT_ANNEX_SHELL_READONLY"
checkNotReadOnly :: IO ()
checkNotReadOnly = checkEnv readOnlyEnv
appendOnlyEnv :: String
appendOnlyEnv = "GIT_ANNEX_SHELL_APPENDONLY"
checkNotAppendOnly :: IO ()
checkNotAppendOnly = checkEnv appendOnlyEnv
checkEnv :: String -> IO ()
checkEnv var = checkEnvSet var >>= \case
False -> noop
True -> giveup $ "Action blocked by " ++ var
checkEnvSet :: String -> IO Bool
checkEnvSet var = getEnv var >>= return . \case
Nothing -> False
Just "" -> False
Just _ -> True
checkDirectory :: Maybe FilePath -> IO ()
checkDirectory mdir = do
v <- getEnv "GIT_ANNEX_SHELL_DIRECTORY"
case (v, mdir) of
(Nothing, _) -> noop
(Just d, Nothing) -> req d Nothing
(Just d, Just dir)
| d `equalFilePath` dir -> noop
| otherwise -> do
home <- myHomeDir
d' <- canondir home d
dir' <- canondir home dir
if d' `equalFilePath` dir'
then noop
else req d' (Just dir')
where
req d mdir' = giveup $ unwords
[ "Only allowed to access"
, d
, maybe "and could not determine directory from command line" ("not " ++) mdir'
]
{- A directory may start with ~/ or in some cases, even /~/,
- or could just be relative to home, or of course could
- be absolute. -}
canondir home d
| "~/" `isPrefixOf` d = return d
| "/~/" `isPrefixOf` d = return $ drop 1 d
| otherwise = relHome $ fromRawFilePath $ absPathFrom
(toRawFilePath home)
(toRawFilePath d)
{- Modifies a Command to check that it is run in either a git-annex
- repository, or a repository with a gcrypt-id set. -}
gitAnnexShellCheck :: Command -> Command
gitAnnexShellCheck = addCheck GitAnnexShellOk okforshell . dontCheck repoExists
where
okforshell = unlessM (isInitialized <||> isJust . gcryptId <$> Annex.getGitConfig) $
giveup "Not a git-annex or gcrypt repository."
{- Used for Commands that don't support proxying. -}
notProxyable :: Command -> Command
notProxyable c = addCheck GitAnnexShellNotProxyable checkok c
where
checkok = Annex.getState Annex.proxyremote >>= \case
Nothing -> return ()
Just _ -> giveup $ "Cannot proxy " ++ cmdname c ++ " command."