subr_log.c revision 1.4
1 /* 2 * Copyright (c) 1982, 1986 Regents of the University of California. 3 * 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 * from: @(#)subr_log.c 7.11 (Berkeley) 3/17/91 34 * $Id: subr_log.c,v 1.4 1993/12/18 04:21:25 mycroft 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/select.h> 49 50 #define LOG_RDPRI (PZERO + 1) 51 52 #define LOG_ASYNC 0x04 53 #define LOG_RDWAIT 0x08 54 55 struct 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 61 int log_open; /* also used in log() */ 62 63 /*ARGSUSED*/ 64 int 65 logopen(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 /* 77 * Potential race here with putchar() but since putchar should be 78 * called by autoconf, msg_magic should be initialized by the time 79 * we get here. 80 */ 81 if (mbp->msg_magic != MSG_MAGIC) { 82 register int i; 83 84 mbp->msg_magic = MSG_MAGIC; 85 mbp->msg_bufx = mbp->msg_bufr = 0; 86 for (i=0; i < MSG_BSIZE; i++) 87 mbp->msg_bufc[i] = 0; 88 } 89 return (0); 90 } 91 92 /*ARGSUSED*/ 93 int 94 logclose(dev, flag) 95 dev_t dev; 96 int flag; 97 { 98 log_open = 0; 99 logsoftc.sc_state = 0; 100 bzero(&logsoftc.sc_selp, sizeof(logsoftc.sc_selp)); 101 return 0; 102 } 103 104 /*ARGSUSED*/ 105 int 106 logread(dev, uio, flag) 107 dev_t dev; 108 struct uio *uio; 109 int flag; 110 { 111 register struct msgbuf *mbp = msgbufp; 112 register long l; 113 register int s; 114 int error = 0; 115 116 s = splhigh(); 117 while (mbp->msg_bufr == mbp->msg_bufx) { 118 if (flag & IO_NDELAY) { 119 splx(s); 120 return (EWOULDBLOCK); 121 } 122 logsoftc.sc_state |= LOG_RDWAIT; 123 if (error = tsleep((caddr_t)mbp, LOG_RDPRI | PCATCH, 124 "klog", 0)) { 125 splx(s); 126 return (error); 127 } 128 } 129 splx(s); 130 logsoftc.sc_state &= ~LOG_RDWAIT; 131 132 while (uio->uio_resid > 0) { 133 l = mbp->msg_bufx - mbp->msg_bufr; 134 if (l < 0) 135 l = MSG_BSIZE - mbp->msg_bufr; 136 l = MIN(l, uio->uio_resid); 137 if (l == 0) 138 break; 139 error = uiomove((caddr_t)&mbp->msg_bufc[mbp->msg_bufr], 140 (int)l, uio); 141 if (error) 142 break; 143 mbp->msg_bufr += l; 144 if (mbp->msg_bufr < 0 || mbp->msg_bufr >= MSG_BSIZE) 145 mbp->msg_bufr = 0; 146 } 147 return (error); 148 } 149 150 /*ARGSUSED*/ 151 int 152 logselect(dev, rw, p) 153 dev_t dev; 154 int rw; 155 struct proc *p; 156 { 157 int s = splhigh(); 158 159 switch (rw) { 160 161 case FREAD: 162 if (msgbufp->msg_bufr != msgbufp->msg_bufx) { 163 splx(s); 164 return (1); 165 } 166 selrecord(p, &logsoftc.sc_selp); 167 break; 168 } 169 splx(s); 170 return (0); 171 } 172 173 void 174 logwakeup() 175 { 176 struct proc *p; 177 178 if (!log_open) 179 return; 180 selwakeup(&logsoftc.sc_selp); 181 if (logsoftc.sc_state & LOG_ASYNC) { 182 if (logsoftc.sc_pgid < 0) 183 gsignal(-logsoftc.sc_pgid, SIGIO); 184 else if (p = pfind(logsoftc.sc_pgid)) 185 psignal(p, SIGIO); 186 } 187 if (logsoftc.sc_state & LOG_RDWAIT) { 188 wakeup((caddr_t)msgbufp); 189 logsoftc.sc_state &= ~LOG_RDWAIT; 190 } 191 } 192 193 /*ARGSUSED*/ 194 int 195 logioctl(dev, com, data, flag) 196 dev_t dev; 197 int com; 198 caddr_t data; 199 int flag; 200 { 201 long l; 202 int s; 203 204 switch (com) { 205 206 /* return number of characters immediately available */ 207 case FIONREAD: 208 s = splhigh(); 209 l = msgbufp->msg_bufx - msgbufp->msg_bufr; 210 splx(s); 211 if (l < 0) 212 l += MSG_BSIZE; 213 *(off_t *)data = l; 214 break; 215 216 case FIONBIO: 217 break; 218 219 case FIOASYNC: 220 if (*(int *)data) 221 logsoftc.sc_state |= LOG_ASYNC; 222 else 223 logsoftc.sc_state &= ~LOG_ASYNC; 224 break; 225 226 case TIOCSPGRP: 227 logsoftc.sc_pgid = *(int *)data; 228 break; 229 230 case TIOCGPGRP: 231 *(int *)data = logsoftc.sc_pgid; 232 break; 233 234 default: 235 return (-1); 236 } 237 return (0); 238 } 239
Indexes created Mon Sep 22 10:09:38 GMT 2025