/* * 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. * 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 8.1 (Berkeley) 6/10/93 * $FreeBSD: src/sys/kern/subr_log.c,v 1.39.2.2 2001/06/02 08:11:25 phk Exp $ * $DragonFly: src/sys/kern/subr_log.c,v 1.10 2006/07/28 02:17:40 dillon Exp $ */ /* * Error log buffer for kernel printf's. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define LOG_ASYNC 0x04 #define LOG_RDWAIT 0x08 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 void logtimeout(void *arg); #define CDEV_MAJOR 7 static struct dev_ops log_ops = { { "log", CDEV_MAJOR, 0 }, .d_open = logopen, .d_close = logclose, .d_read = logread, .d_ioctl = logioctl, .d_poll = logpoll, }; 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() */ /* 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 dev_open_args *ap) { struct proc *p = curproc; KKASSERT(p != NULL); if (log_open) return (EBUSY); log_open = 1; callout_init(&logsoftc.sc_callout); fsetown(p->p_pid, &logsoftc.sc_sigio); /* signal process only */ callout_reset(&logsoftc.sc_callout, hz / log_wakeups_per_second, logtimeout, NULL); return (0); } /*ARGSUSED*/ static int logclose(struct dev_close_args *ap) { log_open = 0; callout_stop(&logsoftc.sc_callout); logsoftc.sc_state = 0; funsetown(logsoftc.sc_sigio); return (0); } /*ARGSUSED*/ static int logread(struct dev_read_args *ap) { struct uio *uio = ap->a_uio; struct msgbuf *mbp = msgbufp; long l; int error = 0; crit_enter(); while (mbp->msg_bufr == mbp->msg_bufx) { if (ap->a_ioflag & IO_NDELAY) { crit_exit(); return (EWOULDBLOCK); } logsoftc.sc_state |= LOG_RDWAIT; if ((error = tsleep((caddr_t)mbp, PCATCH, "klog", 0))) { crit_exit(); return (error); } } crit_exit(); logsoftc.sc_state &= ~LOG_RDWAIT; while (uio->uio_resid > 0) { l = mbp->msg_bufx - mbp->msg_bufr; if (l < 0) l = mbp->msg_size - mbp->msg_bufr; l = (long)szmin(l, uio->uio_resid); if (l == 0) break; error = uiomove((caddr_t)msgbufp->msg_ptr + mbp->msg_bufr, (size_t)l, uio); if (error) break; mbp->msg_bufr += l; if (mbp->msg_bufr >= mbp->msg_size) mbp->msg_bufr = 0; } return (error); } /*ARGSUSED*/ static int logpoll(struct dev_poll_args *ap) { int revents = 0; crit_enter(); if (ap->a_events & (POLLIN | POLLRDNORM)) { if (msgbufp->msg_bufr != msgbufp->msg_bufx) revents |= ap->a_events & (POLLIN | POLLRDNORM); else selrecord(curthread, &logsoftc.sc_selp); } crit_exit(); ap->a_events = revents; return (0); } static void logtimeout(void *arg) { if (!log_open) return; if (msgbuftrigger == 0) { callout_reset(&logsoftc.sc_callout, hz / log_wakeups_per_second, logtimeout, NULL); return; } msgbuftrigger = 0; selwakeup(&logsoftc.sc_selp); if ((logsoftc.sc_state & LOG_ASYNC) && logsoftc.sc_sigio != NULL) pgsigio(logsoftc.sc_sigio, SIGIO, 0); if (logsoftc.sc_state & LOG_RDWAIT) { wakeup((caddr_t)msgbufp); logsoftc.sc_state &= ~LOG_RDWAIT; } callout_reset(&logsoftc.sc_callout, hz / log_wakeups_per_second, logtimeout, NULL); } /*ARGSUSED*/ static int logioctl(struct dev_ioctl_args *ap) { long l; switch (ap->a_cmd) { case FIONREAD: /* return number of characters immediately available */ crit_enter(); l = msgbufp->msg_bufx - msgbufp->msg_bufr; crit_exit(); if (l < 0) l += msgbufp->msg_size; *(int *)ap->a_data = l; break; case FIOASYNC: if (*(int *)ap->a_data) logsoftc.sc_state |= LOG_ASYNC; else logsoftc.sc_state &= ~LOG_ASYNC; break; case FIOSETOWN: return (fsetown(*(int *)ap->a_data, &logsoftc.sc_sigio)); case FIOGETOWN: *(int *)ap->a_data = fgetown(logsoftc.sc_sigio); break; /* This is deprecated, FIOSETOWN should be used instead. */ case TIOCSPGRP: return (fsetown(-(*(int *)ap->a_data), &logsoftc.sc_sigio)); /* This is deprecated, FIOGETOWN should be used instead */ case TIOCGPGRP: *(int *)ap->a_data = -fgetown(logsoftc.sc_sigio); break; default: return (ENOTTY); } return (0); } static void log_drvinit(void *unused) { make_dev(&log_ops, 0, UID_ROOT, GID_WHEEL, 0600, "klog"); } SYSINIT(logdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,log_drvinit,NULL)