1 /* $OpenBSD: subr_log.c,v 1.3 1996/04/21 22:27:17 deraadt Exp $ */ 2 /* $NetBSD: subr_log.c,v 1.11 1996/03/30 22:24:44 christos Exp $ */ 3 4 /* 5 * Copyright (c) 1982, 1986, 1993 6 * The Regents of the University of California. All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * @(#)subr_log.c 8.1 (Berkeley) 6/10/93 37 */ 38 39 /* 40 * Error log buffer for kernel printf's. 41 */ 42 43 #include <sys/param.h> 44 #include <sys/systm.h> 45 #include <sys/proc.h> 46 #include <sys/vnode.h> 47 #include <sys/ioctl.h> 48 #include <sys/msgbuf.h> 49 #include <sys/file.h> 50 #include <sys/signalvar.h> 51 #include <sys/syslog.h> 52 #include <sys/conf.h> 53 54 #define LOG_RDPRI (PZERO + 1) 55 56 #define LOG_ASYNC 0x04 57 #define LOG_RDWAIT 0x08 58 59 struct logsoftc { 60 int sc_state; /* see above for possibilities */ 61 struct selinfo sc_selp; /* process waiting on select call */ 62 int sc_pgid; /* process/group for async I/O */ 63 } logsoftc; 64 65 int log_open; /* also used in log() */ 66 67 /*ARGSUSED*/ 68 int 69 logopen(dev, flags, mode, p) 70 dev_t dev; 71 int flags, mode; 72 struct proc *p; 73 { 74 register struct msgbuf *mbp = msgbufp; 75 76 if (log_open) 77 return (EBUSY); 78 log_open = 1; 79 logsoftc.sc_pgid = p->p_pid; /* signal process only */ 80 /* 81 * Potential race here with putchar() but since putchar should be 82 * called by autoconf, msg_magic should be initialized by the time 83 * we get here. 84 */ 85 if (mbp->msg_magic != MSG_MAGIC) { 86 register int i; 87 88 mbp->msg_magic = MSG_MAGIC; 89 mbp->msg_bufx = mbp->msg_bufr = 0; 90 for (i=0; i < MSG_BSIZE; i++) 91 mbp->msg_bufc[i] = 0; 92 } 93 return (0); 94 } 95 96 /*ARGSUSED*/ 97 int 98 logclose(dev, flag, mode, p) 99 dev_t dev; 100 int flag, mode; 101 struct proc *p; 102 { 103 104 log_open = 0; 105 logsoftc.sc_state = 0; 106 return (0); 107 } 108 109 /*ARGSUSED*/ 110 int 111 logread(dev, uio, flag) 112 dev_t dev; 113 struct uio *uio; 114 int flag; 115 { 116 register struct msgbuf *mbp = msgbufp; 117 register long l; 118 register int s; 119 int error = 0; 120 121 s = splhigh(); 122 while (mbp->msg_bufr == mbp->msg_bufx) { 123 if (flag & IO_NDELAY) { 124 splx(s); 125 return (EWOULDBLOCK); 126 } 127 logsoftc.sc_state |= LOG_RDWAIT; 128 error = tsleep((caddr_t)mbp, LOG_RDPRI | PCATCH, 129 "klog", 0); 130 if (error) { 131 splx(s); 132 return (error); 133 } 134 } 135 splx(s); 136 logsoftc.sc_state &= ~LOG_RDWAIT; 137 138 while (uio->uio_resid > 0) { 139 l = mbp->msg_bufx - mbp->msg_bufr; 140 if (l < 0) 141 l = MSG_BSIZE - mbp->msg_bufr; 142 l = min(l, uio->uio_resid); 143 if (l == 0) 144 break; 145 error = uiomove((caddr_t)&mbp->msg_bufc[mbp->msg_bufr], 146 (int)l, uio); 147 if (error) 148 break; 149 mbp->msg_bufr += l; 150 if (mbp->msg_bufr < 0 || mbp->msg_bufr >= MSG_BSIZE) 151 mbp->msg_bufr = 0; 152 } 153 return (error); 154 } 155 156 /*ARGSUSED*/ 157 int 158 logselect(dev, rw, p) 159 dev_t dev; 160 int rw; 161 struct proc *p; 162 { 163 int s = splhigh(); 164 165 switch (rw) { 166 167 case FREAD: 168 if (msgbufp->msg_bufr != msgbufp->msg_bufx) { 169 splx(s); 170 return (1); 171 } 172 selrecord(p, &logsoftc.sc_selp); 173 break; 174 } 175 splx(s); 176 return (0); 177 } 178 179 void 180 logwakeup() 181 { 182 struct proc *p; 183 184 if (!log_open) 185 return; 186 selwakeup(&logsoftc.sc_selp); 187 if (logsoftc.sc_state & LOG_ASYNC) { 188 if (logsoftc.sc_pgid < 0) 189 gsignal(-logsoftc.sc_pgid, SIGIO); 190 else if ((p = pfind(logsoftc.sc_pgid)) != NULL) 191 psignal(p, SIGIO); 192 } 193 if (logsoftc.sc_state & LOG_RDWAIT) { 194 wakeup((caddr_t)msgbufp); 195 logsoftc.sc_state &= ~LOG_RDWAIT; 196 } 197 } 198 199 /*ARGSUSED*/ 200 int 201 logioctl(dev, com, data, flag, p) 202 dev_t dev; 203 u_long com; 204 caddr_t data; 205 int flag; 206 struct proc *p; 207 { 208 long l; 209 int s; 210 211 switch (com) { 212 213 /* return number of characters immediately available */ 214 case FIONREAD: 215 s = splhigh(); 216 l = msgbufp->msg_bufx - msgbufp->msg_bufr; 217 splx(s); 218 if (l < 0) 219 l += MSG_BSIZE; 220 *(int *)data = l; 221 break; 222 223 case FIONBIO: 224 break; 225 226 case FIOASYNC: 227 if (*(int *)data) 228 logsoftc.sc_state |= LOG_ASYNC; 229 else 230 logsoftc.sc_state &= ~LOG_ASYNC; 231 break; 232 233 case TIOCSPGRP: 234 logsoftc.sc_pgid = *(int *)data; 235 break; 236 237 case TIOCGPGRP: 238 *(int *)data = logsoftc.sc_pgid; 239 break; 240 241 default: 242 return (-1); 243 } 244 return (0); 245 } 246