/* This is the routine which handles console output (ie. stdout). */
static void console_output(struct virtqueue *vq)
{
unsigned int head, out, in;
struct iovec iov[vq->vring.num];
/* We usually wait in here, for the Guest to give us something. */
head = wait_for_vq_desc(vq, iov, &out, &in);
if (in)
errx(1, "Input buffers in console output queue?");
/* writev can return a partial write, so we loop here. */
while (!iov_empty(iov, out)) {
int len = writev(STDOUT_FILENO, iov, out);
if (len <= 0) {
warn("Write to stdout gave %i (%d)", len, errno);
break;
}
iov_consume(iov, out, len);
}
/*
* We're finished with that buffer: if we're going to sleep,
* wait_for_vq_desc() will prod the Guest with an interrupt.
*/
add_used(vq, head, 0);
}
static void console_output(struct virtqueue *vq)
{
unsigned int head, out, in;
struct iovec iov[vq->vring.num];
head = wait_for_vq_desc(vq, iov, &out, &in);
if (in)
errx(1, "Input buffers in console output queue?");
while (!iov_empty(iov, out)) {
int len = writev(STDOUT_FILENO, iov, out);
if (len <= 0) {
warn("Write to stdout gave %i (%d)", len, errno);
break;
}
iov_consume(iov, out, len);
}
add_used(vq, head, 0);
}