Re: [Libguestfs] [PATCH 4/5] fuse: Fix read for empty files.

> From 3c5d63be17d281634f036f53aa32103ad4ab1c41 Mon Sep 17 00:00:00 2001 From: Richard Jones<rjones(a)redhat.com> Date: Tue, 17 Nov 2009 17:02:45 +0000 Subject: [PATCH 4/5] fuse: Fix read for empty files. Error handling for the guestfs_pread call was incorrect, which meant that empty files could produce spurious error messages. --- fuse/guestmount.c | 8 +++++++- 1 files changed, 7 insertions(+), 1 deletions(-) diff --git a/fuse/guestmount.c b/fuse/guestmount.c index 9d16cef..669bf80 100644 --- a/fuse/guestmount.c +++ b/fuse/guestmount.c @@ -621,8 +621,14 @@ fg_read (const char *path, char *buf, size_t size, off_t offset, if (size> limit) size = limit; + /* Note the correct error handling here is tricky, because in the + * case where the call returns a zero-length buffer, it might return + * NULL. However it won't adjust rsize along the error path, so we + * can set rsize to something beforehand and use that as a flag. + */ + rsize = 1; r = guestfs_pread (g, path, size, offset,&rsize); - if (r == NULL) + if (rsize == 1&& r == NULL) return error (); /* This should never happen, but at least it stops us overflowing -- 1.6.5.2