/* $OpenBSD: subr_log.c,v 1.15 2007/09/03 17:51:03 thib Exp $ */ /* $NetBSD: subr_log.c,v 1.11 1996/03/30 22:24:44 christos Exp $ */ /* * 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. 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 #include #include #include #include #include #include #include #include #include #include #define LOG_RDPRI (PZERO + 1) #define LOG_ASYNC 0x04 #define LOG_RDWAIT 0x08 struct logsoftc { int sc_state; /* see above for possibilities */ struct selinfo sc_selp; /* process waiting on select call */ int sc_pgid; /* process/group for async I/O */ uid_t sc_siguid; /* uid for process that set sc_pgid */ uid_t sc_sigeuid; /* euid for process that set sc_pgid */ } logsoftc; int log_open; /* also used in log() */ int msgbufmapped; /* is the message buffer mapped */ int msgbufenabled; /* is logging to the buffer enabled */ struct msgbuf *msgbufp; /* the mapped buffer, itself. */ void filt_logrdetach(struct knote *kn); int filt_logread(struct knote *kn, long hint); struct filterops logread_filtops = { 1, NULL, filt_logrdetach, filt_logread}; void initmsgbuf(caddr_t buf, size_t bufsize) { struct msgbuf *mbp; long new_bufs; /* Sanity-check the given size. */ if (bufsize < sizeof(struct msgbuf)) return; mbp = msgbufp = (struct msgbuf *)buf; new_bufs = bufsize - offsetof(struct msgbuf, msg_bufc); if ((mbp->msg_magic != MSG_MAGIC) || (mbp->msg_bufs != new_bufs) || (mbp->msg_bufr < 0) || (mbp->msg_bufr >= mbp->msg_bufs) || (mbp->msg_bufx < 0) || (mbp->msg_bufx >= mbp->msg_bufs)) { /* * If the buffer magic number is wrong, has changed * size (which shouldn't happen often), or is * internally inconsistent, initialize it. */ bzero(buf, bufsize); mbp->msg_magic = MSG_MAGIC; mbp->msg_bufs = new_bufs; } /* Always start new buffer data on a new line. */ if (mbp->msg_bufx > 0 && mbp->msg_bufc[mbp->msg_bufx - 1] != '\n') msgbuf_putchar('\n'); /* mark it as ready for use. */ msgbufmapped = msgbufenabled = 1; } void msgbuf_putchar(const char c) { struct msgbuf *mbp = msgbufp; if (mbp->msg_magic != MSG_MAGIC) /* Nothing we can do */ return; mbp->msg_bufc[mbp->msg_bufx++] = c; mbp->msg_bufl = min(mbp->msg_bufl+1, mbp->msg_bufs); if (mbp->msg_bufx < 0 || mbp->msg_bufx >= mbp->msg_bufs) mbp->msg_bufx = 0; /* If the buffer is full, keep the most recent data. */ if (mbp->msg_bufr == mbp->msg_bufx) { if (++mbp->msg_bufr >= mbp->msg_bufs) mbp->msg_bufr = 0; } } /*ARGSUSED*/ int logopen(dev_t dev, int flags, int mode, struct proc *p) { if (log_open) return (EBUSY); log_open = 1; return (0); } /*ARGSUSED*/ int logclose(dev_t dev, int flag, int mode, struct proc *p) { log_open = 0; logsoftc.sc_state = 0; return (0); } /*ARGSUSED*/ int logread(dev_t dev, struct uio *uio, int flag) { struct msgbuf *mbp = msgbufp; long l; 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; error = tsleep(mbp, LOG_RDPRI | PCATCH, "klog", 0); if (error) { 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 = mbp->msg_bufs - mbp->msg_bufr; l = min(l, uio->uio_resid); if (l == 0) break; error = uiomove(&mbp->msg_bufc[mbp->msg_bufr], (int)l, uio); if (error) break; mbp->msg_bufr += l; if (mbp->msg_bufr < 0 || mbp->msg_bufr >= mbp->msg_bufs) mbp->msg_bufr = 0; } return (error); } /*ARGSUSED*/ int logpoll(dev_t dev, int events, struct proc *p) { int revents = 0; int s = splhigh(); if (events & (POLLIN | POLLRDNORM)) { if (msgbufp->msg_bufr != msgbufp->msg_bufx) revents |= events & (POLLIN | POLLRDNORM); else selrecord(p, &logsoftc.sc_selp); } splx(s); return (revents); } int logkqfilter(dev_t dev, struct knote *kn) { struct klist *klist; int s; switch (kn->kn_filter) { case EVFILT_READ: klist = &logsoftc.sc_selp.si_note; kn->kn_fop = &logread_filtops; break; default: return (1); } kn->kn_hook = (void *)msgbufp; s = splhigh(); SLIST_INSERT_HEAD(klist, kn, kn_selnext); splx(s); return (0); } void filt_logrdetach(struct knote *kn) { int s = splhigh(); SLIST_REMOVE(&logsoftc.sc_selp.si_note, kn, knote, kn_selnext); splx(s); } int filt_logread(struct knote *kn, long hint) { struct msgbuf *p = (struct msgbuf *)kn->kn_hook; kn->kn_data = (int)(p->msg_bufx - p->msg_bufr); return (p->msg_bufx != p->msg_bufr); } void logwakeup(void) { if (!log_open) return; selwakeup(&logsoftc.sc_selp); if (logsoftc.sc_state & LOG_ASYNC) csignal(logsoftc.sc_pgid, SIGIO, logsoftc.sc_siguid, logsoftc.sc_sigeuid); if (logsoftc.sc_state & LOG_RDWAIT) { wakeup(msgbufp); logsoftc.sc_state &= ~LOG_RDWAIT; } KNOTE(&logsoftc.sc_selp.si_note, 0); } /*ARGSUSED*/ int logioctl(dev_t dev, u_long com, caddr_t data, int flag, struct proc *p) { 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 += msgbufp->msg_bufs; *(int *)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; logsoftc.sc_siguid = p->p_cred->p_ruid; logsoftc.sc_sigeuid = p->p_ucred->cr_uid; break; case TIOCGPGRP: *(int *)data = logsoftc.sc_pgid; break; default: return (ENOTTY); } return (0); }