subr_log.c revision 198860
1139804Simp/*- 21541Srgrimes * Copyright (c) 1982, 1986, 1993 31541Srgrimes * The Regents of the University of California. All rights reserved. 41541Srgrimes * 51541Srgrimes * Redistribution and use in source and binary forms, with or without 61541Srgrimes * modification, are permitted provided that the following conditions 71541Srgrimes * are met: 81541Srgrimes * 1. Redistributions of source code must retain the above copyright 91541Srgrimes * notice, this list of conditions and the following disclaimer. 101541Srgrimes * 2. Redistributions in binary form must reproduce the above copyright 111541Srgrimes * notice, this list of conditions and the following disclaimer in the 121541Srgrimes * documentation and/or other materials provided with the distribution. 131541Srgrimes * 4. Neither the name of the University nor the names of its contributors 141541Srgrimes * may be used to endorse or promote products derived from this software 151541Srgrimes * without specific prior written permission. 161541Srgrimes * 171541Srgrimes * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 181541Srgrimes * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 191541Srgrimes * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 201541Srgrimes * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 211541Srgrimes * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 221541Srgrimes * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 231541Srgrimes * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 241541Srgrimes * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 251541Srgrimes * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 261541Srgrimes * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 271541Srgrimes * SUCH DAMAGE. 281541Srgrimes * 291541Srgrimes * @(#)subr_log.c 8.1 (Berkeley) 6/10/93 301541Srgrimes */ 311541Srgrimes 321541Srgrimes/* 331541Srgrimes * Error log buffer for kernel printf's. 341541Srgrimes */ 351541Srgrimes 36116182Sobrien#include <sys/cdefs.h> 37116182Sobrien__FBSDID("$FreeBSD: head/sys/kern/subr_log.c 198860 2009-11-03 21:06:19Z ed $"); 38116182Sobrien 391541Srgrimes#include <sys/param.h> 401541Srgrimes#include <sys/systm.h> 4112577Sbde#include <sys/conf.h> 421541Srgrimes#include <sys/proc.h> 431541Srgrimes#include <sys/vnode.h> 4424206Sbde#include <sys/filio.h> 4524206Sbde#include <sys/ttycom.h> 461541Srgrimes#include <sys/msgbuf.h> 473308Sphk#include <sys/signalvar.h> 4812517Sjulian#include <sys/kernel.h> 4929357Speter#include <sys/poll.h> 5041086Struckman#include <sys/filedesc.h> 5170069Sjhb#include <sys/sysctl.h> 5212517Sjulian 531541Srgrimes#define LOG_RDPRI (PZERO + 1) 541541Srgrimes 551541Srgrimes#define LOG_ASYNC 0x04 561541Srgrimes 5712675Sjulianstatic d_open_t logopen; 5812675Sjulianstatic d_close_t logclose; 5912675Sjulianstatic d_read_t logread; 6012675Sjulianstatic d_ioctl_t logioctl; 6129357Speterstatic d_poll_t logpoll; 6212675Sjulian 6370069Sjhbstatic void logtimeout(void *arg); 6470069Sjhb 6547625Sphkstatic struct cdevsw log_cdevsw = { 66126080Sphk .d_version = D_VERSION, 67111815Sphk .d_open = logopen, 68111815Sphk .d_close = logclose, 69111815Sphk .d_read = logread, 70111815Sphk .d_ioctl = logioctl, 71111815Sphk .d_poll = logpoll, 72111815Sphk .d_name = "log", 7347625Sphk}; 7412675Sjulian 7512819Sphkstatic struct logsoftc { 761541Srgrimes int sc_state; /* see above for possibilities */ 771541Srgrimes struct selinfo sc_selp; /* process waiting on select call */ 7841087Struckman struct sigio *sc_sigio; /* information for async I/O */ 7970069Sjhb struct callout sc_callout; /* callout to wakeup syslog */ 801541Srgrimes} logsoftc; 811541Srgrimes 82198860Sedint log_open; /* also used in log() */ 83198860Sedstatic struct cv log_wakeup; 84198860Sedstruct mtx msgbuf_lock; 85198860SedMTX_SYSINIT(msgbuf_lock, &msgbuf_lock, "msgbuf lock", MTX_DEF); 861541Srgrimes 8770069Sjhb/* Times per second to check for a pending syslog wakeup. */ 8870069Sjhbstatic int log_wakeups_per_second = 5; 8970069SjhbSYSCTL_INT(_kern, OID_AUTO, log_wakeups_per_second, CTLFLAG_RW, 9070069Sjhb &log_wakeups_per_second, 0, ""); 9170069Sjhb 921541Srgrimes/*ARGSUSED*/ 9312675Sjulianstatic int 94130585Sphklogopen(struct cdev *dev, int flags, int mode, struct thread *td) 951541Srgrimes{ 96198860Sed 97116634Sbmilekic if (log_wakeups_per_second < 1) { 98116634Sbmilekic printf("syslog wakeup is less than one. Adjusting to 1.\n"); 99116634Sbmilekic log_wakeups_per_second = 1; 100116634Sbmilekic } 101198860Sed 102198860Sed mtx_lock(&msgbuf_lock); 103198860Sed if (log_open) { 104198860Sed mtx_unlock(&msgbuf_lock); 105198860Sed return (EBUSY); 106198860Sed } 107198860Sed log_open = 1; 10870069Sjhb callout_reset(&logsoftc.sc_callout, hz / log_wakeups_per_second, 10970069Sjhb logtimeout, NULL); 110198860Sed mtx_unlock(&msgbuf_lock); 111198860Sed 112198860Sed fsetown(td->td_proc->p_pid, &logsoftc.sc_sigio); /* signal process only */ 1131541Srgrimes return (0); 1141541Srgrimes} 1151541Srgrimes 1161541Srgrimes/*ARGSUSED*/ 11712675Sjulianstatic int 118130585Sphklogclose(struct cdev *dev, int flag, int mode, struct thread *td) 1191541Srgrimes{ 1201541Srgrimes 121198860Sed funsetown(&logsoftc.sc_sigio); 122198860Sed 123198860Sed mtx_lock(&msgbuf_lock); 12470069Sjhb callout_stop(&logsoftc.sc_callout); 1251541Srgrimes logsoftc.sc_state = 0; 126198860Sed log_open = 0; 127198860Sed mtx_unlock(&msgbuf_lock); 128198860Sed 1291541Srgrimes return (0); 1301541Srgrimes} 1311541Srgrimes 1321541Srgrimes/*ARGSUSED*/ 13312675Sjulianstatic int 134130585Sphklogread(struct cdev *dev, struct uio *uio, int flag) 1351541Srgrimes{ 136116660Siedowse char buf[128]; 13769741Sphk struct msgbuf *mbp = msgbufp; 138198860Sed int error = 0, l; 1391541Srgrimes 140198860Sed mtx_lock(&msgbuf_lock); 141116660Siedowse while (msgbuf_getcount(mbp) == 0) { 1421541Srgrimes if (flag & IO_NDELAY) { 143198860Sed mtx_unlock(&msgbuf_lock); 1441541Srgrimes return (EWOULDBLOCK); 1451541Srgrimes } 146198860Sed if ((error = cv_wait_sig(&log_wakeup, &msgbuf_lock)) != 0) { 147198860Sed mtx_unlock(&msgbuf_lock); 1481541Srgrimes return (error); 1491541Srgrimes } 1501541Srgrimes } 1511541Srgrimes 1521541Srgrimes while (uio->uio_resid > 0) { 153116660Siedowse l = imin(sizeof(buf), uio->uio_resid); 154116660Siedowse l = msgbuf_getbytes(mbp, buf, l); 1551541Srgrimes if (l == 0) 1561541Srgrimes break; 157198860Sed mtx_unlock(&msgbuf_lock); 158116660Siedowse error = uiomove(buf, l, uio); 159198860Sed if (error || uio->uio_resid == 0) 160198860Sed return (error); 161198860Sed mtx_lock(&msgbuf_lock); 1621541Srgrimes } 163198860Sed mtx_unlock(&msgbuf_lock); 1641541Srgrimes return (error); 1651541Srgrimes} 1661541Srgrimes 1671541Srgrimes/*ARGSUSED*/ 16812675Sjulianstatic int 169130585Sphklogpoll(struct cdev *dev, int events, struct thread *td) 1701541Srgrimes{ 17129357Speter int revents = 0; 1721541Srgrimes 17346568Speter if (events & (POLLIN | POLLRDNORM)) { 174198860Sed mtx_lock(&msgbuf_lock); 175116660Siedowse if (msgbuf_getcount(msgbufp) > 0) 17629357Speter revents |= events & (POLLIN | POLLRDNORM); 17729357Speter else 17883805Sjhb selrecord(td, &logsoftc.sc_selp); 179198860Sed mtx_unlock(&msgbuf_lock); 18046568Speter } 18129357Speter return (revents); 1821541Srgrimes} 1831541Srgrimes 18470069Sjhbstatic void 18570069Sjhblogtimeout(void *arg) 18670069Sjhb{ 18770069Sjhb 18877057Sphk if (!log_open) 18970069Sjhb return; 190116634Sbmilekic if (log_wakeups_per_second < 1) { 191116634Sbmilekic printf("syslog wakeup is less than one. Adjusting to 1.\n"); 192116634Sbmilekic log_wakeups_per_second = 1; 193116634Sbmilekic } 19477057Sphk if (msgbuftrigger == 0) { 195198860Sed callout_schedule(&logsoftc.sc_callout, 196198860Sed hz / log_wakeups_per_second); 19777057Sphk return; 19877057Sphk } 19970239Sphk msgbuftrigger = 0; 200122352Stanimura selwakeuppri(&logsoftc.sc_selp, LOG_RDPRI); 20141086Struckman if ((logsoftc.sc_state & LOG_ASYNC) && logsoftc.sc_sigio != NULL) 20295883Salfred pgsigio(&logsoftc.sc_sigio, SIGIO, 0); 203198860Sed cv_broadcastpri(&log_wakeup, LOG_RDPRI); 204198860Sed callout_schedule(&logsoftc.sc_callout, hz / log_wakeups_per_second); 2051541Srgrimes} 2061541Srgrimes 2071541Srgrimes/*ARGSUSED*/ 20812675Sjulianstatic int 209130585Sphklogioctl(struct cdev *dev, u_long com, caddr_t data, int flag, struct thread *td) 2101541Srgrimes{ 2111541Srgrimes 2121541Srgrimes switch (com) { 2131541Srgrimes 2141541Srgrimes /* return number of characters immediately available */ 2151541Srgrimes case FIONREAD: 216116660Siedowse *(int *)data = msgbuf_getcount(msgbufp); 2171541Srgrimes break; 2181541Srgrimes 2191541Srgrimes case FIONBIO: 2201541Srgrimes break; 2211541Srgrimes 2221541Srgrimes case FIOASYNC: 223198860Sed mtx_lock(&msgbuf_lock); 2241541Srgrimes if (*(int *)data) 2251541Srgrimes logsoftc.sc_state |= LOG_ASYNC; 2261541Srgrimes else 2271541Srgrimes logsoftc.sc_state &= ~LOG_ASYNC; 228198860Sed mtx_unlock(&msgbuf_lock); 2291541Srgrimes break; 2301541Srgrimes 23141086Struckman case FIOSETOWN: 23241086Struckman return (fsetown(*(int *)data, &logsoftc.sc_sigio)); 23341086Struckman 23441086Struckman case FIOGETOWN: 235104393Struckman *(int *)data = fgetown(&logsoftc.sc_sigio); 2361541Srgrimes break; 2371541Srgrimes 23841086Struckman /* This is deprecated, FIOSETOWN should be used instead. */ 23941086Struckman case TIOCSPGRP: 24041086Struckman return (fsetown(-(*(int *)data), &logsoftc.sc_sigio)); 24141086Struckman 24241086Struckman /* This is deprecated, FIOGETOWN should be used instead */ 2431541Srgrimes case TIOCGPGRP: 244104393Struckman *(int *)data = -fgetown(&logsoftc.sc_sigio); 2451541Srgrimes break; 2461541Srgrimes 2471541Srgrimes default: 2488161Sjkh return (ENOTTY); 2491541Srgrimes } 2501541Srgrimes return (0); 2511541Srgrimes} 25212517Sjulian 25312675Sjulianstatic void 25469741Sphklog_drvinit(void *unused) 25512517Sjulian{ 25669741Sphk 257198860Sed cv_init(&log_wakeup, "klog"); 258198860Sed callout_init_mtx(&logsoftc.sc_callout, &msgbuf_lock, 0); 25950254Sphk make_dev(&log_cdevsw, 0, UID_ROOT, GID_WHEEL, 0600, "klog"); 26012517Sjulian} 26112517Sjulian 262177253SrwatsonSYSINIT(logdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE,log_drvinit,NULL); 263