summaryrefslogtreecommitdiff
path: root/src/Propellor/Bootstrap.hs
diff options
context:
space:
mode:
authorJoey Hess2015-09-25 09:24:16 -0400
committerJoey Hess2015-09-25 09:24:16 -0400
commit39a89b0827fca8a62bb80cf12a5abc75661bdaf9 (patch)
treeedc6bd924160a63778c2444729e33e52e5a4497a /src/Propellor/Bootstrap.hs
parentb424c3da63bdb9897123b4481a02e087590bcc03 (diff)
Guard against power loss etc when building propellor, by updating the executable atomically.
Diffstat (limited to 'src/Propellor/Bootstrap.hs')
-rw-r--r--src/Propellor/Bootstrap.hs17
1 files changed, 15 insertions, 2 deletions
diff --git a/src/Propellor/Bootstrap.hs b/src/Propellor/Bootstrap.hs
index 6812b4ab..b2cf5609 100644
--- a/src/Propellor/Bootstrap.hs
+++ b/src/Propellor/Bootstrap.hs
@@ -104,9 +104,22 @@ build = catchBoolIO $ do
void $ cabal ["configure"]
unlessM (cabal ["build"]) $
error "cabal build failed"
- nukeFile "propellor"
- createSymbolicLink "dist/build/propellor-config/propellor-config" "propellor"
+ -- For safety against eg power loss in the middle of the build,
+ -- make a copy of the binary, and move it into place atomically.
+ -- This ensures that the propellor symlink only ever points at
+ -- a binary that is fully built. Also, avoid ever removing
+ -- or breaking the symlink.
+ unlessM (boolSystem "cp" [Param cabalbuiltbin, Param (tmpfor safetycopy)]) $
+ error "cp of binary failed"
+ rename (tmpfor safetycopy) safetycopy
+ createSymbolicLink safetycopy (tmpfor dest)
+ rename (tmpfor dest) dest
return True
+ where
+ dest = "propellor"
+ cabalbuiltbin = "dist/build/propellor-config/propellor-config"
+ safetycopy = cabalbuiltbin ++ ".built"
+ tmpfor f = f ++ ".propellortmp"
make :: FilePath -> [FilePath] -> IO Bool -> IO ()
make dest srcs builder = do