try to get rid of races in hostfs open()
In case of mode mismatch, do *not* blindly close the descriptor
another openers might be using right now. Open the underlying
file with currently sufficient mode, then
* if current mode has grown so that it's sufficient for
us now, just close our new fd
* if current mode has grown and our fd is *not* enough
to cover it, close and repeat.
* otherwise, install our fd if the file hadn't been
opened at all or dup2() our fd over the current one (and close
our fd).
Critical section is protected by mutex; yes, system-wide. All
we do under it is a bunch of comparison and maybe an overwriting
dup2() on host.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/hostfs/hostfs_user.c b/fs/hostfs/hostfs_user.c
index 91ebfce..6777aa0 100644
--- a/fs/hostfs/hostfs_user.c
+++ b/fs/hostfs/hostfs_user.c
@@ -160,6 +160,11 @@
return 0;
}
+int replace_file(int oldfd, int fd)
+{
+ return dup2(oldfd, fd);
+}
+
void close_file(void *stream)
{
close(*((int *) stream));