+/*
+ * Copyright (c) 1982, 1986 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.
+ * 3. All advertising materials mentioning features or use of this software
+ * must display the following acknowledgement:
+ * This product includes software developed by the University of
+ * California, Berkeley and its contributors.
+ * 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 7.11 (Berkeley) 3/17/91
+ */
+
+/*
+ * Error log buffer for kernel printf's.
+ */
+
+#include "param.h"
+#include "proc.h"
+#include "vnode.h"
+#include "ioctl.h"
+#include "msgbuf.h"
+#include "file.h"
+
+#define LOG_RDPRI (PZERO + 1)
+
+#define LOG_ASYNC 0x04
+#define LOG_RDWAIT 0x08
+
+struct logsoftc {
+ int sc_state; /* see above for possibilities */
+ struct proc *sc_selp; /* process waiting on select call */
+ int sc_pgid; /* process/group for async I/O */
+} logsoftc;
+
+int log_open; /* also used in log() */
+
+/*ARGSUSED*/
+logopen(dev, flags, mode, p)
+ dev_t dev;
+ int flags, mode;
+ struct proc *p;
+{
+ register struct msgbuf *mbp = msgbufp;
+
+ if (log_open)
+ return (EBUSY);
+ log_open = 1;
+ logsoftc.sc_pgid = p->p_pid; /* signal process only */
+ /*
+ * Potential race here with putchar() but since putchar should be
+ * called by autoconf, msg_magic should be initialized by the time
+ * we get here.
+ */
+ if (mbp->msg_magic != MSG_MAGIC) {
+ register int i;
+
+ mbp->msg_magic = MSG_MAGIC;
+ mbp->msg_bufx = mbp->msg_bufr = 0;
+ for (i=0; i < MSG_BSIZE; i++)
+ mbp->msg_bufc[i] = 0;
+ }
+ return (0);
+}
+
+/*ARGSUSED*/
+logclose(dev, flag)
+ dev_t dev;
+{
+ log_open = 0;
+ logsoftc.sc_state = 0;
+ logsoftc.sc_selp = 0;
+}
+
+/*ARGSUSED*/
+logread(dev, uio, flag)
+ dev_t dev;
+ struct uio *uio;
+ int flag;
+{
+ register struct msgbuf *mbp = msgbufp;
+ register long l;
+ register int s;
+ int error = 0;
+
+ s = splhigh();
+ while (mbp->msg_bufr == mbp->msg_bufx) {
+ if (flag & IO_NDELAY) {
+ splx(s);
+ return (EWOULDBLOCK);
+ }
+ logsoftc.sc_state |= LOG_RDWAIT;
+ if (error = tsleep((caddr_t)mbp, LOG_RDPRI | PCATCH,
+ "klog", 0)) {
+ splx(s);
+ return (error);
+ }
+ }
+ splx(s);
+ logsoftc.sc_state &= ~LOG_RDWAIT;
+
+ while (uio->uio_resid > 0) {
+ l = mbp->msg_bufx - mbp->msg_bufr;
+ if (l < 0)
+ l = MSG_BSIZE - mbp->msg_bufr;
+ l = MIN(l, uio->uio_resid);
+ if (l == 0)
+ break;
+ error = uiomove((caddr_t)&mbp->msg_bufc[mbp->msg_bufr],
+ (int)l, uio);
+ if (error)
+ break;
+ mbp->msg_bufr += l;
+ if (mbp->msg_bufr < 0 || mbp->msg_bufr >= MSG_BSIZE)
+ mbp->msg_bufr = 0;
+ }
+ return (error);
+}
+
+/*ARGSUSED*/
+logselect(dev, rw, p)
+ dev_t dev;
+ int rw;
+ struct proc *p;
+{
+ int s = splhigh();
+
+ switch (rw) {
+
+ case FREAD:
+ if (msgbufp->msg_bufr != msgbufp->msg_bufx) {
+ splx(s);
+ return (1);
+ }
+ logsoftc.sc_selp = p;
+ break;
+ }
+ splx(s);
+ return (0);
+}
+
+logwakeup()
+{
+ struct proc *p;
+
+ if (!log_open)
+ return;
+ if (logsoftc.sc_selp) {
+ selwakeup(logsoftc.sc_selp, 0);
+ logsoftc.sc_selp = 0;
+ }
+ if (logsoftc.sc_state & LOG_ASYNC) {
+ if (logsoftc.sc_pgid < 0)
+ gsignal(-logsoftc.sc_pgid, SIGIO);
+ else if (p = pfind(logsoftc.sc_pgid))
+ psignal(p, SIGIO);
+ }
+ if (logsoftc.sc_state & LOG_RDWAIT) {
+ wakeup((caddr_t)msgbufp);
+ logsoftc.sc_state &= ~LOG_RDWAIT;
+ }
+}
+
+/*ARGSUSED*/
+logioctl(dev, com, data, flag)
+ caddr_t data;
+{
+ long l;
+ int s;
+
+ switch (com) {
+
+ /* return number of characters immediately available */
+ case FIONREAD:
+ s = splhigh();
+ l = msgbufp->msg_bufx - msgbufp->msg_bufr;
+ splx(s);
+ if (l < 0)
+ l += MSG_BSIZE;
+ *(off_t *)data = l;
+ break;
+
+ case FIONBIO:
+ break;
+
+ case FIOASYNC:
+ if (*(int *)data)
+ logsoftc.sc_state |= LOG_ASYNC;
+ else
+ logsoftc.sc_state &= ~LOG_ASYNC;
+ break;
+
+ case TIOCSPGRP:
+ logsoftc.sc_pgid = *(int *)data;
+ break;
+
+ case TIOCGPGRP:
+ *(int *)data = logsoftc.sc_pgid;
+ break;
+
+ default:
+ return (-1);
+ }
+ return (0);
+}
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