qemu-char: retry g_poll on EINTR

This is a case where pty_chr_update_read_handler_locked's lack
of error checking can produce incorrect values.  We are not using
SIGUSR1 anymore, so this is quite theoretical, but easy to fix.

Reported-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 6 insertions, 1 deletions

diff --git a/qemu-char.c b/qemu-char.c
index 5448b0f..2969c44 100644
--- a/qemu-char.c
+++ b/qemu-char.c
@@ -1241,11 +1241,16 @@ static void pty_chr_update_read_handler_locked(CharDriverState *chr)
 {
     PtyCharDriver *s = chr->opaque;
     GPollFD pfd;
+    int rc;
 
     pfd.fd = g_io_channel_unix_get_fd(s->fd);
     pfd.events = G_IO_OUT;
     pfd.revents = 0;
-    g_poll(&pfd, 1, 0);
+    do {
+        rc = g_poll(&pfd, 1, 0);
+    } while (rc == -1 && errno == EINTR);
+    assert(rc >= 0);
+
     if (pfd.revents & G_IO_HUP) {
         pty_chr_state(chr, 0);
     } else {