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chardev/char-socket: tcp_chr_sync_read: don't clobber errno 

After the return from tcp_chr_recv, tcp_chr_sync_read calls into a
function which eventually makes a system call and may clobber errno.

Make a copy of errno right after tcp_chr_recv and restore the errno on
return from tcp_chr_sync_read.

Signed-off-by: Roman Kagan <rvkagan@yandex-team.ru>
Message-Id: <20211111153354.18807-4-rvkagan@yandex-team.ru>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
This commit is contained in:
Roman Kagan 2021-11-11 18:33:47 +03:00 committed by Michael S. Tsirkin
parent e87975051e
commit 666265036f
1 changed files with 3 additions and 0 deletions
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3
chardev/char-socket.c
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@ -525,6 +525,7 @@ static int tcp_chr_sync_read(Chardev *chr, const uint8_t *buf, int len)
{
SocketChardev *s = SOCKET_CHARDEV(chr);
int size;
int saved_errno;
if (s->state != TCP_CHARDEV_STATE_CONNECTED) {
return 0;
@ -532,6 +533,7 @@ static int tcp_chr_sync_read(Chardev *chr, const uint8_t *buf, int len)
qio_channel_set_blocking(s->ioc, true, NULL);
size = tcp_chr_recv(chr, (void *) buf, len);
saved_errno = errno;
if (s->state != TCP_CHARDEV_STATE_DISCONNECTED) {
qio_channel_set_blocking(s->ioc, false, NULL);
}
@ -540,6 +542,7 @@ static int tcp_chr_sync_read(Chardev *chr, const uint8_t *buf, int len)
tcp_chr_disconnect(chr);
}
errno = saved_errno;
return size;
}