From: Roman Kagan <rvka...@yandex-team.ru> 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 <rvka...@yandex-team.ru> Message-Id: <20211111153354.18807-4-rvka...@yandex-team.ru> Reviewed-by: Michael S. Tsirkin <m...@redhat.com> Signed-off-by: Michael S. Tsirkin <m...@redhat.com> Reviewed-by: Marc-André Lureau <marcandre.lur...@redhat.com> --- chardev/char-socket.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/chardev/char-socket.c b/chardev/char-socket.c index 3ddd98ed49..fab2d791d4 100644 --- a/chardev/char-socket.c +++ b/chardev/char-socket.c @@ -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; } -- MST