From 3e5e0faf9cf93c01fb621774c0c3c50ce51bdd91 Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <e.dolstra@tudelft.nl>
Date: Mon, 21 Jun 2010 11:08:09 +0000
Subject: [PATCH] * Okay, putting a lock on the temporary directory used by
 importPath()   doesn't work because the garbage collector doesn't actually
 look at   locks.  So r22253 was stupid.  Use addTempRoot() instead.  Also,  
 locking the temporary directory in exportPath() was silly because it   isn't
 even in the store.

---
 src/libstore/local-store.cc | 24 ++++++++++++++++++------
 src/libstore/local-store.hh |  2 ++
 2 files changed, 20 insertions(+), 6 deletions(-)

diff --git a/src/libstore/local-store.cc b/src/libstore/local-store.cc
index c7530f1b1..6f3d9efa8 100644
--- a/src/libstore/local-store.cc
+++ b/src/libstore/local-store.cc
@@ -1036,8 +1036,6 @@ void LocalStore::exportPath(const Path & path, bool sign,
         writeInt(1, hashAndWriteSink);
         
         Path tmpDir = createTempDir();
-        PathLocks tmpDirLock(singleton<PathSet, Path>(tmpDir));
-        tmpDirLock.setDeletion(true);
         AutoDelete delTmp(tmpDir);
         Path hashFile = tmpDir + "/hash";
         writeFile(hashFile, printHash(hash));
@@ -1079,6 +1077,22 @@ struct HashAndReadSource : Source
 };
 
 
+/* Create a temporary directory in the store that won't be
+   garbage-collected. */
+Path LocalStore::createTempDirInStore()
+{
+    Path tmpDir;
+    do {
+        /* There is a slight possibility that `tmpDir' gets deleted by
+           the GC between createTempDir() and addTempRoot(), so repeat
+           until `tmpDir' exists. */
+        tmpDir = createTempDir(nixStore);
+        addTempRoot(tmpDir);
+    } while (!pathExists(tmpDir));
+    return tmpDir;
+}
+
+
 Path LocalStore::importPath(bool requireSignature, Source & source)
 {
     HashAndReadSource hashAndReadSource(source);
@@ -1086,10 +1100,8 @@ Path LocalStore::importPath(bool requireSignature, Source & source)
     /* We don't yet know what store path this archive contains (the
        store path follows the archive data proper), and besides, we
        don't know yet whether the signature is valid. */
-    Path tmpDir = createTempDir(nixStore);
-    PathLocks tmpDirLock(singleton<PathSet, Path>(tmpDir));
-    tmpDirLock.setDeletion(true);
-    AutoDelete delTmp(tmpDir); /* !!! could be GC'ed! */
+    Path tmpDir = createTempDirInStore();
+    AutoDelete delTmp(tmpDir);
     Path unpacked = tmpDir + "/unpacked";
 
     restorePath(unpacked, hashAndReadSource);
diff --git a/src/libstore/local-store.hh b/src/libstore/local-store.hh
index c1e0e335f..3ae964f05 100644
--- a/src/libstore/local-store.hh
+++ b/src/libstore/local-store.hh
@@ -246,6 +246,8 @@ private:
         
     void startSubstituter(const Path & substituter,
         RunningSubstituter & runningSubstituter);
+
+    Path createTempDirInStore();
 };