subr_log.c revision 9979
1/* 2 * Copyright (c) 1982, 1986, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * @(#)subr_log.c 8.1 (Berkeley) 6/10/93 34 * $Id: subr_log.c,v 1.8 1995/05/30 08:05:52 rgrimes Exp $ 35 */ 36 37/* 38 * Error log buffer for kernel printf's. 39 */ 40 41#include <sys/param.h> 42#include <sys/systm.h> 43#include <sys/proc.h> 44#include <sys/vnode.h> 45#include <sys/ioctl.h> 46#include <sys/msgbuf.h> 47#include <sys/file.h> 48#include <sys/signalvar.h> 49 50#define LOG_RDPRI (PZERO + 1) 51 52#define LOG_ASYNC 0x04 53#define LOG_RDWAIT 0x08 54 55struct logsoftc { 56 int sc_state; /* see above for possibilities */ 57 struct selinfo sc_selp; /* process waiting on select call */ 58 int sc_pgid; /* process/group for async I/O */ 59} logsoftc; 60 61int log_open; /* also used in log() */ 62 63/*ARGSUSED*/ 64int 65logopen(dev, flags, mode, p) 66 dev_t dev; 67 int flags, mode; 68 struct proc *p; 69{ 70 register struct msgbuf *mbp = msgbufp; 71 72 if (log_open) 73 return (EBUSY); 74 log_open = 1; 75 logsoftc.sc_pgid = p->p_pid; /* signal process only */ 76 return (0); 77} 78 79/*ARGSUSED*/ 80int 81logclose(dev, flag, mode, p) 82 dev_t dev; 83 int flag, mode; 84 struct proc *p; 85{ 86 87 log_open = 0; 88 logsoftc.sc_state = 0; 89 return (0); 90} 91 92/*ARGSUSED*/ 93int 94logread(dev, uio, flag) 95 dev_t dev; 96 struct uio *uio; 97 int flag; 98{ 99 register struct msgbuf *mbp = msgbufp; 100 register long l; 101 register int s; 102 int error = 0; 103 104 s = splhigh(); 105 while (mbp->msg_bufr == mbp->msg_bufx) { 106 if (flag & IO_NDELAY) { 107 splx(s); 108 return (EWOULDBLOCK); 109 } 110 logsoftc.sc_state |= LOG_RDWAIT; 111 if ((error = tsleep((caddr_t)mbp, LOG_RDPRI | PCATCH, 112 "klog", 0))) { 113 splx(s); 114 return (error); 115 } 116 } 117 splx(s); 118 logsoftc.sc_state &= ~LOG_RDWAIT; 119 120 while (uio->uio_resid > 0) { 121 l = mbp->msg_bufx - mbp->msg_bufr; 122 if (l < 0) 123 l = MSG_BSIZE - mbp->msg_bufr; 124 l = min(l, uio->uio_resid); 125 if (l == 0) 126 break; 127 error = uiomove((caddr_t)&mbp->msg_bufc[mbp->msg_bufr], 128 (int)l, uio); 129 if (error) 130 break; 131 mbp->msg_bufr += l; 132 if (mbp->msg_bufr >= MSG_BSIZE) 133 mbp->msg_bufr = 0; 134 } 135 return (error); 136} 137 138/*ARGSUSED*/ 139int 140logselect(dev, rw, p) 141 dev_t dev; 142 int rw; 143 struct proc *p; 144{ 145 int s = splhigh(); 146 147 switch (rw) { 148 149 case FREAD: 150 if (msgbufp->msg_bufr != msgbufp->msg_bufx) { 151 splx(s); 152 return (1); 153 } 154 selrecord(p, &logsoftc.sc_selp); 155 break; 156 } 157 splx(s); 158 return (0); 159} 160 161void 162logwakeup() 163{ 164 struct proc *p; 165 166 if (!log_open) 167 return; 168 selwakeup(&logsoftc.sc_selp); 169 if (logsoftc.sc_state & LOG_ASYNC) { 170 if (logsoftc.sc_pgid < 0) 171 gsignal(-logsoftc.sc_pgid, SIGIO); 172 else if ((p = pfind(logsoftc.sc_pgid))) 173 psignal(p, SIGIO); 174 } 175 if (logsoftc.sc_state & LOG_RDWAIT) { 176 wakeup((caddr_t)msgbufp); 177 logsoftc.sc_state &= ~LOG_RDWAIT; 178 } 179} 180 181/*ARGSUSED*/ 182int 183logioctl(dev, com, data, flag, p) 184 dev_t dev; 185 int com; 186 caddr_t data; 187 int flag; 188 struct proc *p; 189{ 190 long l; 191 int s; 192 193 switch (com) { 194 195 /* return number of characters immediately available */ 196 case FIONREAD: 197 s = splhigh(); 198 l = msgbufp->msg_bufx - msgbufp->msg_bufr; 199 splx(s); 200 if (l < 0) 201 l += MSG_BSIZE; 202 *(int *)data = l; 203 break; 204 205 case FIONBIO: 206 break; 207 208 case FIOASYNC: 209 if (*(int *)data) 210 logsoftc.sc_state |= LOG_ASYNC; 211 else 212 logsoftc.sc_state &= ~LOG_ASYNC; 213 break; 214 215 case TIOCSPGRP: 216 logsoftc.sc_pgid = *(int *)data; 217 break; 218 219 case TIOCGPGRP: 220 *(int *)data = logsoftc.sc_pgid; 221 break; 222 223 default: 224 return (ENOTTY); 225 } 226 return (0); 227} 228