From 86fd2b88a37f29226a2e09f215373a04cc23c8c1 Mon Sep 17 00:00:00 2001
From: =?utf8?q?Eduard=20Vintil=C4=83?= <eduard.vintila47@gmail.com>
Date: Sat, 11 Mar 2023 20:29:59 +0200
Subject: [PATCH] lib/posix-event: Update `uio_offset` and `uio_resid` on
 successful reads
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This commit updates (on a sucessful read) the `uio_offset` and
`uio_resid` members of the `uio` structure passed to the
`eventfd_vfscore_read` function. Without updating those members, the
`read` function from the vfscore layer will always report that no bytes
have been read at all.

Signed-off-by: Eduard Vintilă <eduard.vintila47@gmail.com>
Reviewed-by: Cezar Craciunoiu <cezar.craciunoiu@unikraft.io>
Reviewed-by: Delia Pavel <delia_maria.pavel@stud.acs.upb.ro>
Reviewed-by: Razvan Deaconescu <razvand@unikraft.io>
Approved-by: Razvan Deaconescu <razvand@unikraft.io>
Tested-by: Unikraft CI <monkey@unikraft.io>
GitHub-Closes: #798
---
 lib/posix-event/eventfd.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/lib/posix-event/eventfd.c b/lib/posix-event/eventfd.c
index 916103aec..bb14bb7b6 100644
--- a/lib/posix-event/eventfd.c
+++ b/lib/posix-event/eventfd.c
@@ -173,6 +173,9 @@ static int eventfd_vfscore_read(struct vnode *vnode,
 
 	uk_mutex_unlock(&efd->lock);
 
+	buf->uio_resid = 0;
+	buf->uio_offset = sizeof(uint64_t);
+
 	return 0;
 }
 
-- 
2.39.5