change backup log format so it can also log when backup of a key was skipped

This will be used later when keysafe --autostart prompts if the user wants
to back up their gpg key. Making the change now before the backup log
format gets frozen.

This commit was sponsored by Josh Taylor on Patreon.

3 files changed, 40 insertions, 30 deletions

diff --git a/BackupRecord.hs b/BackupLog.hs
index 88a9b68..8e48bcd 100644
--- a/BackupRecord.hs
+++ b/BackupLog.hs
@@ -5,11 +5,11 @@
 
 {-# LANGUAGE DeriveGeneric, BangPatterns #-}
 
-module BackupRecord where
+module BackupLog where
 
 import Types
-import Types.Cost
 import Types.Server
+import Types.Cost
 import Utility.UserInfo
 import GHC.Generics
 import Data.Time.Clock.POSIX
@@ -20,7 +20,13 @@ import System.Directory
 import System.Posix.Files
 import qualified Data.ByteString.Lazy as B
 
--- | Record of a backup.
+data BackupLog = BackupLog POSIXTime BackupEvent
+	deriving (Show, Generic)
+
+instance ToJSON BackupLog
+instance FromJSON BackupLog
+
+-- | Log of a backup.
 --
 -- If an attacker cracks the user's system and finds this stored
 -- on it, it should not help them recover keys from keysafe.
@@ -31,41 +37,45 @@ import qualified Data.ByteString.Lazy as B
 -- Including the password entropy does let an attacker avoid trying
 -- weak passwords and go right to passwords that are strong enough, but
 -- this should only half the password crack time at worst.
-data BackupRecord = BackupRecord
-	{ backupDate :: POSIXTime
-	, backupServers :: [ServerName]
-	, secretKeySource :: SecretKeySource
-	, passwordEntropy :: Int
-	} deriving (Show, Generic)
+data BackupEvent = BackupSkipped SecretKeySource | BackupMade
+	{ backupServers :: [ServerName]
+	, backupSecretKeySource :: SecretKeySource
+	, backupPasswordEntropy :: Int
+	}
+	deriving (Show, Generic)
 
--- BackupRecord is serialized as JSON.
-instance ToJSON BackupRecord
-instance FromJSON BackupRecord
+instance ToJSON BackupEvent
+instance FromJSON BackupEvent
 
-mkBackupRecord :: [Server] -> SecretKeySource -> Entropy UnknownPassword -> IO BackupRecord
-mkBackupRecord servers sks (Entropy n) = BackupRecord
+mkBackupLog :: BackupEvent -> IO BackupLog
+mkBackupLog evt = BackupLog
 	<$> getPOSIXTime
-	<*> pure (map serverName servers)
-	<*> pure sks
-	<*> pure n
+	<*> pure evt
+
+backupMade :: [Server] -> SecretKeySource -> Entropy UnknownPassword -> BackupEvent
+backupMade servers sks (Entropy n) = BackupMade
+	{ backupServers = map serverName servers
+	, backupSecretKeySource = sks
+	, backupPasswordEntropy = n
+	}
 
-backupRecordFile :: IO FilePath
-backupRecordFile = do
+backupLogFile :: IO FilePath
+backupLogFile = do
 	home <- myHomeDir
 	return $ home </> ".keysafe/backup.log"
 
-readBackupRecords :: IO [BackupRecord]
-readBackupRecords = do
-	f <- backupRecordFile
+readBackupLogs :: IO [BackupLog]
+readBackupLogs = do
+	f <- backupLogFile
 	e <- doesFileExist f
 	if e
 		then fromMaybe [] . decode <$> B.readFile f
 		else return []
 
-storeBackupRecord :: BackupRecord -> IO ()
-storeBackupRecord r = do
-	!rs <- readBackupRecords
-	f <- backupRecordFile
+storeBackupLog :: BackupLog -> IO ()
+storeBackupLog r = do
+	!rs <- readBackupLogs
+	f <- backupLogFile
 	let d = takeDirectory f
 	createDirectoryIfMissing True d
 	setFileMode d $
diff --git a/keysafe.cabal b/keysafe.cabal
index dc90e3c..02622b7 100644
--- a/keysafe.cabal
+++ b/keysafe.cabal
@@ -78,7 +78,7 @@ Executable keysafe
   Extra-Libraries: argon2
   Other-Modules:
     AutoStart
-    BackupRecord
+    BackupLog
     Benchmark
     ByteStrings
     Crypto.Argon2.FFI
diff --git a/keysafe.hs b/keysafe.hs
index 6d5186a..7fe27cf 100644
--- a/keysafe.hs
+++ b/keysafe.hs
@@ -19,7 +19,7 @@ import Cost
 import SecretKey
 import Share
 import Storage
-import BackupRecord
+import BackupLog
 import AutoStart
 import HTTP.Server
 import ServerBackup
@@ -114,10 +114,10 @@ backup cmdline storagelocations ui tunables secretkeysource secretkey = do
 				_ <- sis `seq` addpercent 25
 				let step = 50 `div` sum (map S.size shares)
 				storeShares storagelocations sis shares (addpercent step)
-		backuprecord <- mkBackupRecord (mapMaybe getServer locs) secretkeysource passwordentropy
+		backuplog <- mkBackupLog $ backupMade (mapMaybe getServer locs) secretkeysource passwordentropy
 		case r of
 			StoreSuccess -> do
-				storeBackupRecord backuprecord
+				storeBackupLog backuplog
 				if queued
 					then do
 						willautostart <- isAutoStartFileInstalled