1 /* $NetBSD: subr_log.c,v 1.12 1996/09/07 12:40:58 mycroft Exp $ */ 2 3 /* 4 * Copyright (c) 1982, 1986, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by the University of 18 * California, Berkeley and its contributors. 19 * 4. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 * 35 * @(#)subr_log.c 8.1 (Berkeley) 6/10/93 36 */ 37 38 /* 39 * Error log buffer for kernel printf's. 40 */ 41 42 #include <sys/param.h> 43 #include <sys/systm.h> 44 #include <sys/proc.h> 45 #include <sys/vnode.h> 46 #include <sys/ioctl.h> 47 #include <sys/msgbuf.h> 48 #include <sys/file.h> 49 #include <sys/signalvar.h> 50 #include <sys/syslog.h> 51 #include <sys/conf.h> 52 #include <sys/select.h> 53 #include <sys/poll.h> 54 55 #define LOG_RDPRI (PZERO + 1) 56 57 #define LOG_ASYNC 0x04 58 #define LOG_RDWAIT 0x08 59 60 struct logsoftc { 61 int sc_state; /* see above for possibilities */ 62 struct selinfo sc_selp; /* process waiting on select call */ 63 int sc_pgid; /* process/group for async I/O */ 64 } logsoftc; 65 66 int log_open; /* also used in log() */ 67 68 /*ARGSUSED*/ 69 int 70 logopen(dev, flags, mode, p) 71 dev_t dev; 72 int flags, mode; 73 struct proc *p; 74 { 75 register struct msgbuf *mbp = msgbufp; 76 77 if (log_open) 78 return (EBUSY); 79 log_open = 1; 80 logsoftc.sc_pgid = p->p_pid; /* signal process only */ 81 /* 82 * Potential race here with putchar() but since putchar should be 83 * called by autoconf, msg_magic should be initialized by the time 84 * we get here. 85 */ 86 if (mbp->msg_magic != MSG_MAGIC) { 87 register int i; 88 89 mbp->msg_magic = MSG_MAGIC; 90 mbp->msg_bufx = mbp->msg_bufr = 0; 91 for (i=0; i < MSG_BSIZE; i++) 92 mbp->msg_bufc[i] = 0; 93 } 94 return (0); 95 } 96 97 /*ARGSUSED*/ 98 int 99 logclose(dev, flag, mode, p) 100 dev_t dev; 101 int flag, mode; 102 struct proc *p; 103 { 104 105 log_open = 0; 106 logsoftc.sc_state = 0; 107 return (0); 108 } 109 110 /*ARGSUSED*/ 111 int 112 logread(dev, uio, flag) 113 dev_t dev; 114 struct uio *uio; 115 int flag; 116 { 117 register struct msgbuf *mbp = msgbufp; 118 register long l; 119 register int s; 120 int error = 0; 121 122 s = splhigh(); 123 while (mbp->msg_bufr == mbp->msg_bufx) { 124 if (flag & IO_NDELAY) { 125 splx(s); 126 return (EWOULDBLOCK); 127 } 128 logsoftc.sc_state |= LOG_RDWAIT; 129 error = tsleep((caddr_t)mbp, LOG_RDPRI | PCATCH, 130 "klog", 0); 131 if (error) { 132 splx(s); 133 return (error); 134 } 135 } 136 splx(s); 137 logsoftc.sc_state &= ~LOG_RDWAIT; 138 139 while (uio->uio_resid > 0) { 140 l = mbp->msg_bufx - mbp->msg_bufr; 141 if (l < 0) 142 l = MSG_BSIZE - mbp->msg_bufr; 143 l = min(l, uio->uio_resid); 144 if (l == 0) 145 break; 146 error = uiomove((caddr_t)&mbp->msg_bufc[mbp->msg_bufr], 147 (int)l, uio); 148 if (error) 149 break; 150 mbp->msg_bufr += l; 151 if (mbp->msg_bufr < 0 || mbp->msg_bufr >= MSG_BSIZE) 152 mbp->msg_bufr = 0; 153 } 154 return (error); 155 } 156 157 /*ARGSUSED*/ 158 int 159 logpoll(dev, events, p) 160 dev_t dev; 161 int events; 162 struct proc *p; 163 { 164 int revents = 0; 165 int s = splhigh(); 166 167 if (events & (POLLIN | POLLRDNORM)) 168 if (msgbufp->msg_bufr != msgbufp->msg_bufx) 169 revents |= events & (POLLIN | POLLRDNORM); 170 else 171 selrecord(p, &logsoftc.sc_selp); 172 173 splx(s); 174 return (revents); 175 } 176 177 void 178 logwakeup() 179 { 180 struct proc *p; 181 182 if (!log_open) 183 return; 184 selwakeup(&logsoftc.sc_selp); 185 if (logsoftc.sc_state & LOG_ASYNC) { 186 if (logsoftc.sc_pgid < 0) 187 gsignal(-logsoftc.sc_pgid, SIGIO); 188 else if ((p = pfind(logsoftc.sc_pgid)) != NULL) 189 psignal(p, SIGIO); 190 } 191 if (logsoftc.sc_state & LOG_RDWAIT) { 192 wakeup((caddr_t)msgbufp); 193 logsoftc.sc_state &= ~LOG_RDWAIT; 194 } 195 } 196 197 /*ARGSUSED*/ 198 int 199 logioctl(dev, com, data, flag, p) 200 dev_t dev; 201 u_long com; 202 caddr_t data; 203 int flag; 204 struct proc *p; 205 { 206 long l; 207 int s; 208 209 switch (com) { 210 211 /* return number of characters immediately available */ 212 case FIONREAD: 213 s = splhigh(); 214 l = msgbufp->msg_bufx - msgbufp->msg_bufr; 215 splx(s); 216 if (l < 0) 217 l += MSG_BSIZE; 218 *(int *)data = l; 219 break; 220 221 case FIONBIO: 222 break; 223 224 case FIOASYNC: 225 if (*(int *)data) 226 logsoftc.sc_state |= LOG_ASYNC; 227 else 228 logsoftc.sc_state &= ~LOG_ASYNC; 229 break; 230 231 case TIOCSPGRP: 232 logsoftc.sc_pgid = *(int *)data; 233 break; 234 235 case TIOCGPGRP: 236 *(int *)data = logsoftc.sc_pgid; 237 break; 238 239 default: 240 return (-1); 241 } 242 return (0); 243 } 244