Use O_CLOEXEC in most places

src/libstore/build.cc

@@ -509,10 +509,9 @@ void UserLock::acquire()
             /* We already have a lock on this one. */
             continue;
 
-        AutoCloseFD fd = open(fnUserLock.c_str(), O_RDWR | O_CREAT, 0600);
+        AutoCloseFD fd = open(fnUserLock.c_str(), O_RDWR | O_CREAT | O_CLOEXEC, 0600);
         if (fd == -1)
             throw SysError(format("opening user lock ‘%1%’") % fnUserLock);
-        closeOnExec(fd);
 
         if (lockFile(fd, ltWrite, false)) {
             fdUserLock = fd.borrow();

src/libstore/gc.cc

@@ -33,10 +33,9 @@ int LocalStore::openGCLock(LockType lockType)
 
     debug(format("acquiring global GC lock ‘%1%’") % fnGCLock);
 
-    AutoCloseFD fdGCLock = open(fnGCLock.c_str(), O_RDWR | O_CREAT, 0600);
+    AutoCloseFD fdGCLock = open(fnGCLock.c_str(), O_RDWR | O_CREAT | O_CLOEXEC, 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..."));
@@ -211,7 +210,7 @@ void LocalStore::readTempRoots(PathSet & tempRoots, FDs & fds)
         Path path = (format("%1%/%2%/%3%") % stateDir % tempRootsDir % i.name).str();
 
         debug(format("reading temporary root file ‘%1%’") % path);
-        FDPtr fd(new AutoCloseFD(open(path.c_str(), O_RDWR, 0666)));
+        FDPtr fd(new AutoCloseFD(open(path.c_str(), O_CLOEXEC | O_RDWR, 0666)));
         if (*fd == -1) {
             /* It's okay if the file has disappeared. */
             if (errno == ENOENT) continue;

src/libstore/local-store.cc

@@ -117,7 +117,7 @@ LocalStore::LocalStore(const Params & params)
         if (stat(reservedPath.c_str(), &st) == -1 ||
             st.st_size != settings.reservedSize)
         {
-            AutoCloseFD fd = open(reservedPath.c_str(), O_WRONLY | O_CREAT, 0600);
+            AutoCloseFD fd = open(reservedPath.c_str(), O_WRONLY | O_CREAT | O_CLOEXEC, 0600);
             int res = -1;
 #if HAVE_POSIX_FALLOCATE
             res = posix_fallocate(fd, 0, settings.reservedSize);
@@ -1245,7 +1245,7 @@ static void makeMutable(const Path & path)
     /* The O_NOFOLLOW is important to prevent us from changing the
        mutable bit on the target of a symlink (which would be a
        security hole). */
-    AutoCloseFD fd = open(path.c_str(), O_RDONLY | O_NOFOLLOW);
+    AutoCloseFD fd = open(path.c_str(), O_RDONLY | O_NOFOLLOW | O_CLOEXEC);
     if (fd == -1) {
         if (errno == ELOOP) return; // it's a symlink
         throw SysError(format("opening file ‘%1%’") % path);

src/libstore/pathlocks.cc

@@ -16,12 +16,10 @@ int openLockFile(const Path & path, bool create)
 {
     AutoCloseFD fd;
 
-    fd = open(path.c_str(), O_RDWR | (create ? O_CREAT : 0), 0600);
+    fd = open(path.c_str(), O_CLOEXEC | O_RDWR | (create ? O_CREAT : 0), 0600);
     if (fd == -1 && (create || errno != ENOENT))
         throw SysError(format("opening lock file ‘%1%’") % path);
 
-    closeOnExec(fd);
-
     return fd.borrow();
 }
 

src/libstore/remote-store.cc

@@ -61,7 +61,11 @@ ref<RemoteStore::Connection> RemoteStore::openConnection()
     auto conn = make_ref<Connection>();
 
     /* Connect to a daemon that does the privileged work for us. */
-    conn->fd = socket(PF_UNIX, SOCK_STREAM, 0);
+    conn->fd = socket(PF_UNIX, SOCK_STREAM
+        #ifdef SOCK_CLOEXEC
+        | SOCK_CLOEXEC
+        #endif
+        , 0);
     if (conn->fd == -1)
         throw SysError("cannot create Unix domain socket");
     closeOnExec(conn->fd);