[PATCHv2 1/2] xread: retry after poll on EAGAIN/EWOULDBLOCK

[Eric Wong <e@80x24.org>]

Jeff King <peff@peff.net> wrote:
> On Sun, Jun 26, 2016 at 11:21:11PM +0000, Eric Wong wrote:
> 
> > We should continue to loop after EAGAIN/EWOULDBLOCK as the
> > intent of xread is to read as much as possible until an
> > EOF or real error occurs.
> 
> BTW, a minor nit here. xread() does _not_ read as much as possible until
> EOF. It tries until it gets a real error or at least one byte.
> 
> I know you inherited this mistaken text from 1079c4be0b, but we should
> probably not repeat it.

Good catch, here's v2 of PATCH 1/2 reworded:

----------8<----------
Subject: [PATCH] xread: retry after poll on EAGAIN/EWOULDBLOCK

We should continue to loop after EAGAIN/EWOULDBLOCK as the
intent of xread is to try until there is available data,
EOF, or an unrecoverable error.

Fixes: 1079c4be0b720 ("xread: poll on non blocking fds")

Signed-off-by: Eric Wong <e@80x24.org>
---
 wrapper.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/wrapper.c b/wrapper.c
index 5dc4e15..f1155d0 100644
--- a/wrapper.c
+++ b/wrapper.c
@@ -255,6 +255,7 @@ ssize_t xread(int fd, void *buf, size_t len)
 				 * call to read(2).
 				 */
 				poll(&pfd, 1, -1);
+				continue;
 			}
 		}
 		return nr;
-- 
EW