subr_log.c revision 1.6
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 * from: @(#)subr_log.c 8.1 (Berkeley) 6/10/93 34 * $Id: subr_log.c,v 1.6 1994/05/19 08:13:44 cgd 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 49 #define LOG_RDPRI (PZERO + 1) 50 51 #define LOG_ASYNC 0x04 52 #define LOG_RDWAIT 0x08 53 54 struct logsoftc { 55 int sc_state; /* see above for possibilities */ 56 struct selinfo sc_selp; /* process waiting on select call */ 57 int sc_pgid; /* process/group for async I/O */ 58 } logsoftc; 59 60 int log_open; /* also used in log() */ 61 62 /*ARGSUSED*/ 63 int 64 logopen(dev, flags, mode, p) 65 dev_t dev; 66 int flags, mode; 67 struct proc *p; 68 { 69 register struct msgbuf *mbp = msgbufp; 70 71 if (log_open) 72 return (EBUSY); 73 log_open = 1; 74 logsoftc.sc_pgid = p->p_pid; /* signal process only */ 75 /* 76 * Potential race here with putchar() but since putchar should be 77 * called by autoconf, msg_magic should be initialized by the time 78 * we get here. 79 */ 80 if (mbp->msg_magic != MSG_MAGIC) { 81 register int i; 82 83 mbp->msg_magic = MSG_MAGIC; 84 mbp->msg_bufx = mbp->msg_bufr = 0; 85 for (i=0; i < MSG_BSIZE; i++) 86 mbp->msg_bufc[i] = 0; 87 } 88 return (0); 89 } 90 91 /*ARGSUSED*/ 92 int 93 logclose(dev, flag, mode, p) 94 dev_t dev; 95 int flag; 96 { 97 98 log_open = 0; 99 logsoftc.sc_state = 0; 100 return (0); 101 } 102 103 /*ARGSUSED*/ 104 int 105 logread(dev, uio, flag) 106 dev_t dev; 107 struct uio *uio; 108 int flag; 109 { 110 register struct msgbuf *mbp = msgbufp; 111 register long l; 112 register int s; 113 int error = 0; 114 115 s = splhigh(); 116 while (mbp->msg_bufr == mbp->msg_bufx) { 117 if (flag & IO_NDELAY) { 118 splx(s); 119 return (EWOULDBLOCK); 120 } 121 logsoftc.sc_state |= LOG_RDWAIT; 122 if (error = tsleep((caddr_t)mbp, LOG_RDPRI | PCATCH, 123 "klog", 0)) { 124 splx(s); 125 return (error); 126 } 127 } 128 splx(s); 129 logsoftc.sc_state &= ~LOG_RDWAIT; 130 131 while (uio->uio_resid > 0) { 132 l = mbp->msg_bufx - mbp->msg_bufr; 133 if (l < 0) 134 l = MSG_BSIZE - mbp->msg_bufr; 135 l = min(l, uio->uio_resid); 136 if (l == 0) 137 break; 138 error = uiomove((caddr_t)&mbp->msg_bufc[mbp->msg_bufr], 139 (int)l, uio); 140 if (error) 141 break; 142 mbp->msg_bufr += l; 143 if (mbp->msg_bufr < 0 || mbp->msg_bufr >= MSG_BSIZE) 144 mbp->msg_bufr = 0; 145 } 146 return (error); 147 } 148 149 /*ARGSUSED*/ 150 int 151 logselect(dev, rw, p) 152 dev_t dev; 153 int rw; 154 struct proc *p; 155 { 156 int s = splhigh(); 157 158 switch (rw) { 159 160 case FREAD: 161 if (msgbufp->msg_bufr != msgbufp->msg_bufx) { 162 splx(s); 163 return (1); 164 } 165 selrecord(p, &logsoftc.sc_selp); 166 break; 167 } 168 splx(s); 169 return (0); 170 } 171 172 void 173 logwakeup() 174 { 175 struct proc *p; 176 177 if (!log_open) 178 return; 179 selwakeup(&logsoftc.sc_selp); 180 if (logsoftc.sc_state & LOG_ASYNC) { 181 if (logsoftc.sc_pgid < 0) 182 gsignal(-logsoftc.sc_pgid, SIGIO); 183 else if (p = pfind(logsoftc.sc_pgid)) 184 psignal(p, SIGIO); 185 } 186 if (logsoftc.sc_state & LOG_RDWAIT) { 187 wakeup((caddr_t)msgbufp); 188 logsoftc.sc_state &= ~LOG_RDWAIT; 189 } 190 } 191 192 /*ARGSUSED*/ 193 int 194 logioctl(dev, com, data, flag) 195 dev_t dev; 196 int com; 197 caddr_t data; 198 int flag; 199 { 200 long l; 201 int s; 202 203 switch (com) { 204 205 /* return number of characters immediately available */ 206 case FIONREAD: 207 s = splhigh(); 208 l = msgbufp->msg_bufx - msgbufp->msg_bufr; 209 splx(s); 210 if (l < 0) 211 l += MSG_BSIZE; 212 *(int *)data = l; 213 break; 214 215 case FIONBIO: 216 break; 217 218 case FIOASYNC: 219 if (*(int *)data) 220 logsoftc.sc_state |= LOG_ASYNC; 221 else 222 logsoftc.sc_state &= ~LOG_ASYNC; 223 break; 224 225 case TIOCSPGRP: 226 logsoftc.sc_pgid = *(int *)data; 227 break; 228 229 case TIOCGPGRP: 230 *(int *)data = logsoftc.sc_pgid; 231 break; 232 233 default: 234 return (-1); 235 } 236 return (0); 237 } 238
Indexes created Tue Sep 23 14:10:03 GMT 2025