1 files changed, 310 insertions, 0 deletions

diff --git a/sys/kern/subr_log.c b/sys/kern/subr_log.c
new file mode 100644
index 0000000..1e61274
--- /dev/null
+++ b/sys/kern/subr_log.c
@@ -0,0 +1,310 @@
+/*-
+ * Copyright (c) 1982, 1986, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)subr_log.c	8.1 (Berkeley) 6/10/93
+ */
+
+/*
+ * Error log buffer for kernel printf's.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/conf.h>
+#include <sys/proc.h>
+#include <sys/vnode.h>
+#include <sys/filio.h>
+#include <sys/ttycom.h>
+#include <sys/msgbuf.h>
+#include <sys/signalvar.h>
+#include <sys/kernel.h>
+#include <sys/poll.h>
+#include <sys/filedesc.h>
+#include <sys/sysctl.h>
+
+#define LOG_RDPRI	(PZERO + 1)
+
+#define LOG_ASYNC	0x04
+
+static	d_open_t	logopen;
+static	d_close_t	logclose;
+static	d_read_t	logread;
+static	d_ioctl_t	logioctl;
+static	d_poll_t	logpoll;
+static	d_kqfilter_t	logkqfilter;
+
+static	void logtimeout(void *arg);
+
+static struct cdevsw log_cdevsw = {
+	.d_version =	D_VERSION,
+	.d_open =	logopen,
+	.d_close =	logclose,
+	.d_read =	logread,
+	.d_ioctl =	logioctl,
+	.d_poll =	logpoll,
+	.d_kqfilter =	logkqfilter,
+	.d_name =	"log",
+};
+
+static int	logkqread(struct knote *note, long hint);
+static void	logkqdetach(struct knote *note);
+
+static struct filterops log_read_filterops = {
+	.f_isfd =	1,
+	.f_attach =	NULL,
+	.f_detach =	logkqdetach,
+	.f_event =	logkqread,
+};
+
+static struct logsoftc {
+	int	sc_state;		/* see above for possibilities */
+	struct	selinfo sc_selp;	/* process waiting on select call */
+	struct  sigio *sc_sigio;	/* information for async I/O */
+	struct	callout sc_callout;	/* callout to wakeup syslog  */
+} logsoftc;
+
+int			log_open;	/* also used in log() */
+static struct cv	log_wakeup;
+struct mtx		msgbuf_lock;
+MTX_SYSINIT(msgbuf_lock, &msgbuf_lock, "msgbuf lock", MTX_DEF);
+
+/* Times per second to check for a pending syslog wakeup. */
+static int	log_wakeups_per_second = 5;
+SYSCTL_INT(_kern, OID_AUTO, log_wakeups_per_second, CTLFLAG_RW,
+    &log_wakeups_per_second, 0, "");
+
+/*ARGSUSED*/
+static	int
+logopen(struct cdev *dev, int flags, int mode, struct thread *td)
+{
+
+	if (log_wakeups_per_second < 1) {
+		printf("syslog wakeup is less than one.  Adjusting to 1.\n");
+		log_wakeups_per_second = 1;
+	}
+
+	mtx_lock(&msgbuf_lock);
+	if (log_open) {
+		mtx_unlock(&msgbuf_lock);
+		return (EBUSY);
+	}
+	log_open = 1;
+	callout_reset_sbt(&logsoftc.sc_callout,
+	    SBT_1S / log_wakeups_per_second, 0, logtimeout, NULL, C_PREL(1));
+	mtx_unlock(&msgbuf_lock);
+
+	fsetown(td->td_proc->p_pid, &logsoftc.sc_sigio);	/* signal process only */
+	return (0);
+}
+
+/*ARGSUSED*/
+static	int
+logclose(struct cdev *dev, int flag, int mode, struct thread *td)
+{
+
+	funsetown(&logsoftc.sc_sigio);
+
+	mtx_lock(&msgbuf_lock);
+	callout_stop(&logsoftc.sc_callout);
+	logsoftc.sc_state = 0;
+	log_open = 0;
+	mtx_unlock(&msgbuf_lock);
+
+	return (0);
+}
+
+/*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
+logpoll(struct cdev *dev, int events, struct thread *td)
+{
+	int revents = 0;
+
+	if (events & (POLLIN | POLLRDNORM)) {
+		mtx_lock(&msgbuf_lock);
+		if (msgbuf_getcount(msgbufp) > 0)
+			revents |= events & (POLLIN | POLLRDNORM);
+		else
+			selrecord(td, &logsoftc.sc_selp);
+		mtx_unlock(&msgbuf_lock);
+	}
+	return (revents);
+}
+
+static int
+logkqfilter(struct cdev *dev, struct knote *kn)
+{
+
+	if (kn->kn_filter != EVFILT_READ)
+		return (EINVAL);
+
+	kn->kn_fop = &log_read_filterops;
+	kn->kn_hook = NULL;
+
+	mtx_lock(&msgbuf_lock);
+	knlist_add(&logsoftc.sc_selp.si_note, kn, 1);
+	mtx_unlock(&msgbuf_lock);
+	return (0);
+}
+
+static int
+logkqread(struct knote *kn, long hint)
+{
+
+	mtx_assert(&msgbuf_lock, MA_OWNED);
+	kn->kn_data = msgbuf_getcount(msgbufp);
+	return (kn->kn_data != 0);
+}
+
+static void
+logkqdetach(struct knote *kn)
+{
+
+	mtx_lock(&msgbuf_lock);
+	knlist_remove(&logsoftc.sc_selp.si_note, kn, 1);
+	mtx_unlock(&msgbuf_lock);
+}
+
+static void
+logtimeout(void *arg)
+{
+
+	if (!log_open)
+		return;
+	if (msgbuftrigger == 0)
+		goto done;
+	msgbuftrigger = 0;
+	selwakeuppri(&logsoftc.sc_selp, LOG_RDPRI);
+	KNOTE_LOCKED(&logsoftc.sc_selp.si_note, 0);
+	if ((logsoftc.sc_state & LOG_ASYNC) && logsoftc.sc_sigio != NULL)
+		pgsigio(&logsoftc.sc_sigio, SIGIO, 0);
+	cv_broadcastpri(&log_wakeup, LOG_RDPRI);
+done:
+	if (log_wakeups_per_second < 1) {
+		printf("syslog wakeup is less than one.  Adjusting to 1.\n");
+		log_wakeups_per_second = 1;
+	}
+	callout_reset_sbt(&logsoftc.sc_callout,
+	    SBT_1S / log_wakeups_per_second, 0, logtimeout, NULL, C_PREL(1));
+}
+
+/*ARGSUSED*/
+static	int
+logioctl(struct cdev *dev, u_long com, caddr_t data, int flag, struct thread *td)
+{
+
+	switch (com) {
+
+	/* return number of characters immediately available */
+	case FIONREAD:
+		*(int *)data = msgbuf_getcount(msgbufp);
+		break;
+
+	case FIONBIO:
+		break;
+
+	case FIOASYNC:
+		mtx_lock(&msgbuf_lock);
+		if (*(int *)data)
+			logsoftc.sc_state |= LOG_ASYNC;
+		else
+			logsoftc.sc_state &= ~LOG_ASYNC;
+		mtx_unlock(&msgbuf_lock);
+		break;
+
+	case FIOSETOWN:
+		return (fsetown(*(int *)data, &logsoftc.sc_sigio));
+
+	case FIOGETOWN:
+		*(int *)data = fgetown(&logsoftc.sc_sigio);
+		break;
+
+	/* This is deprecated, FIOSETOWN should be used instead. */
+	case TIOCSPGRP:
+		return (fsetown(-(*(int *)data), &logsoftc.sc_sigio));
+
+	/* This is deprecated, FIOGETOWN should be used instead */
+	case TIOCGPGRP:
+		*(int *)data = -fgetown(&logsoftc.sc_sigio);
+		break;
+
+	default:
+		return (ENOTTY);
+	}
+	return (0);
+}
+
+static void
+log_drvinit(void *unused)
+{
+
+	cv_init(&log_wakeup, "klog");
+	callout_init_mtx(&logsoftc.sc_callout, &msgbuf_lock, 0);
+	knlist_init_mtx(&logsoftc.sc_selp.si_note, &msgbuf_lock);
+	make_dev_credf(MAKEDEV_ETERNAL, &log_cdevsw, 0, NULL, UID_ROOT,
+	    GID_WHEEL, 0600, "klog");
+}
+
+SYSINIT(logdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE,log_drvinit,NULL);