3 files changed, 5 insertions, 3 deletions
diff --git a/src/libstore/build.cc b/src/libstore/build.cc
index 5bdd49bac067..467f16597440 100644
--- a/src/libstore/build.cc
+++ b/src/libstore/build.cc
@@ -492,6 +492,7 @@ void UserLock::acquire()
         AutoCloseFD fd = open(fnUserLock.c_str(), O_RDWR | O_CREAT, 0600);
         if (fd == -1)
             throw SysError(format("opening user lock `%1%'") % fnUserLock);
+        closeOnExec(fd);
 
         if (lockFile(fd, ltWrite, false)) {
             fdUserLock = fd.borrow();
@@ -1792,9 +1793,6 @@ void DerivationGoal::startBuilder()
             if (chdir(tmpDir.c_str()) == -1)
                 throw SysError(format("changing into `%1%'") % tmpDir);
 
-            /* Close all other file descriptors. */
-            closeMostFDs(set<int>());
-
 #ifdef CAN_DO_LINUX32_BUILDS
             if (drv.platform == "i686-linux" && thisSystem == "x86_64-linux") {
                 if (personality(0x0008 | 0x8000000 /* == PER_LINUX32_3GB */) == -1)
@@ -2026,6 +2024,7 @@ Path DerivationGoal::openLogFile()
         O_CREAT | O_WRONLY | O_TRUNC, 0666);
     if (fdLogFile == -1)
         throw SysError(format("creating log file `%1%'") % logFileName);
+    closeOnExec(fdLogFile);
 
     return logFileName;
 }
diff --git a/src/libstore/gc.cc b/src/libstore/gc.cc
index e1e7b4c1c54f..e27c63de26ae 100644
--- a/src/libstore/gc.cc
+++ b/src/libstore/gc.cc
@@ -40,6 +40,7 @@ int LocalStore::openGCLock(LockType lockType)
     AutoCloseFD fdGCLock = open(fnGCLock.c_str(), O_RDWR | O_CREAT, 0600);
     if (fdGCLock == -1)
         throw SysError(format("opening global GC lock `%1%'") % fnGCLock);
+    closeOnExec(fdGCLock);
 
     if (!lockFile(fdGCLock, lockType, false)) {
         printMsg(lvlError, format("waiting for the big garbage collector lock..."));
diff --git a/src/libstore/pathlocks.cc b/src/libstore/pathlocks.cc
index 645f4cd67e7e..b858ed238de0 100644
--- a/src/libstore/pathlocks.cc
+++ b/src/libstore/pathlocks.cc
@@ -20,6 +20,8 @@ int openLockFile(const Path & path, bool create)
     if (fd == -1 && (create || errno != ENOENT))
         throw SysError(format("opening lock file `%1%'") % path);
 
+    closeOnExec(fd);
+
     return fd.borrow();
 }