Function logread

freebsd/kern/subr_log.c:147–179

ARGSUSED*/

/*ARGSUSED*/
static	int
logread(struct cdev *dev, struct uio *uio, int flag)
{
	char buf[128];
	struct msgbuf *mbp = msgbufp;
	int error = 0, l;

	mtx_lock(&msgbuf_lock);
	while (msgbuf_getcount(mbp) == 0) {
		if (flag & IO_NDELAY) {
			mtx_unlock(&msgbuf_lock);
			return (EWOULDBLOCK);
		}
		if ((error = cv_wait_sig(&log_wakeup, &msgbuf_lock)) != 0) {
			mtx_unlock(&msgbuf_lock);
			return (error);
		}
	}

	while (uio->uio_resid > 0) {
		l = imin(sizeof(buf), uio->uio_resid);
		l = msgbuf_getbytes(mbp, buf, l);
		if (l == 0)
			break;
		mtx_unlock(&msgbuf_lock);
		error = uiomove(buf, l, uio);
		if (error || uio->uio_resid == 0)
			return (error);
		mtx_lock(&msgbuf_lock);
	}
	mtx_unlock(&msgbuf_lock);
	return (error);
}

/*ARGSUSED*/
static	int