subr_log.c revision 1.3.4.1
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 1.3.4.1 1993/09/24 08:51:24 mycroft Exp $ 35 */ 36 37 /* 38 * Error log buffer for kernel printf's. 39 */ 40 41 #include "param.h" 42 #include "systm.h" 43 #include "proc.h" 44 #include "vnode.h" 45 #include "ioctl.h" 46 #include "msgbuf.h" 47 #include "file.h" 48 #include "select.h" 49 50 #include "machine/cpu.h" 51 52 #define LOG_RDPRI (PZERO + 1) 53 54 #define LOG_ASYNC 0x04 55 #define LOG_RDWAIT 0x08 56 57 struct logsoftc { 58 int sc_state; /* see above for possibilities */ 59 struct selinfo sc_selp; /* process waiting on select call */ 60 int sc_pgid; /* process/group for async I/O */ 61 } logsoftc; 62 63 int log_open; /* also used in log() */ 64 65 /*ARGSUSED*/ 66 int 67 logopen(dev, flags, mode, p) 68 dev_t dev; 69 int flags, mode; 70 struct proc *p; 71 { 72 register struct msgbuf *mbp = msgbufp; 73 74 if (log_open) 75 return (EBUSY); 76 log_open = 1; 77 logsoftc.sc_pgid = p->p_pid; /* signal process only */ 78 /* 79 * Potential race here with putchar() but since putchar should be 80 * called by autoconf, msg_magic should be initialized by the time 81 * we get here. 82 */ 83 if (mbp->msg_magic != MSG_MAGIC) { 84 register int i; 85 86 mbp->msg_magic = MSG_MAGIC; 87 mbp->msg_bufx = mbp->msg_bufr = 0; 88 for (i=0; i < MSG_BSIZE; i++) 89 mbp->msg_bufc[i] = 0; 90 } 91 return (0); 92 } 93 94 /*ARGSUSED*/ 95 int 96 logclose(dev, flag) 97 dev_t dev; 98 int flag; 99 { 100 log_open = 0; 101 logsoftc.sc_state = 0; 102 bzero(&logsoftc.sc_selp, sizeof(logsoftc.sc_selp)); 103 return 0; 104 } 105 106 /*ARGSUSED*/ 107 int 108 logread(dev, uio, flag) 109 dev_t dev; 110 struct uio *uio; 111 int flag; 112 { 113 register struct msgbuf *mbp = msgbufp; 114 register long l; 115 register int s; 116 int error = 0; 117 118 s = splhigh(); 119 while (mbp->msg_bufr == mbp->msg_bufx) { 120 if (flag & IO_NDELAY) { 121 splx(s); 122 return (EWOULDBLOCK); 123 } 124 logsoftc.sc_state |= LOG_RDWAIT; 125 if (error = tsleep((caddr_t)mbp, LOG_RDPRI | PCATCH, 126 "klog", 0)) { 127 splx(s); 128 return (error); 129 } 130 } 131 splx(s); 132 logsoftc.sc_state &= ~LOG_RDWAIT; 133 134 while (uio->uio_resid > 0) { 135 l = mbp->msg_bufx - mbp->msg_bufr; 136 if (l < 0) 137 l = MSG_BSIZE - mbp->msg_bufr; 138 l = MIN(l, uio->uio_resid); 139 if (l == 0) 140 break; 141 error = uiomove((caddr_t)&mbp->msg_bufc[mbp->msg_bufr], 142 (int)l, uio); 143 if (error) 144 break; 145 mbp->msg_bufr += l; 146 if (mbp->msg_bufr < 0 || mbp->msg_bufr >= MSG_BSIZE) 147 mbp->msg_bufr = 0; 148 } 149 return (error); 150 } 151 152 /*ARGSUSED*/ 153 int 154 logselect(dev, rw, p) 155 dev_t dev; 156 int rw; 157 struct proc *p; 158 { 159 int s = splhigh(); 160 161 switch (rw) { 162 163 case FREAD: 164 if (msgbufp->msg_bufr != msgbufp->msg_bufx) { 165 splx(s); 166 return (1); 167 } 168 selrecord(p, &logsoftc.sc_selp); 169 break; 170 } 171 splx(s); 172 return (0); 173 } 174 175 void 176 logwakeup() 177 { 178 struct proc *p; 179 180 if (!log_open) 181 return; 182 selwakeup(&logsoftc.sc_selp); 183 if (logsoftc.sc_state & LOG_ASYNC) { 184 if (logsoftc.sc_pgid < 0) 185 gsignal(-logsoftc.sc_pgid, SIGIO); 186 else if (p = pfind(logsoftc.sc_pgid)) 187 psignal(p, SIGIO); 188 } 189 if (logsoftc.sc_state & LOG_RDWAIT) { 190 wakeup((caddr_t)msgbufp); 191 logsoftc.sc_state &= ~LOG_RDWAIT; 192 } 193 } 194 195 /*ARGSUSED*/ 196 int 197 logioctl(dev, com, data, flag) 198 dev_t dev; 199 int com; 200 caddr_t data; 201 int flag; 202 { 203 long l; 204 int s; 205 206 switch (com) { 207 208 /* return number of characters immediately available */ 209 case FIONREAD: 210 s = splhigh(); 211 l = msgbufp->msg_bufx - msgbufp->msg_bufr; 212 splx(s); 213 if (l < 0) 214 l += MSG_BSIZE; 215 *(off_t *)data = l; 216 break; 217 218 case FIONBIO: 219 break; 220 221 case FIOASYNC: 222 if (*(int *)data) 223 logsoftc.sc_state |= LOG_ASYNC; 224 else 225 logsoftc.sc_state &= ~LOG_ASYNC; 226 break; 227 228 case TIOCSPGRP: 229 logsoftc.sc_pgid = *(int *)data; 230 break; 231 232 case TIOCGPGRP: 233 *(int *)data = logsoftc.sc_pgid; 234 break; 235 236 default: 237 return (-1); 238 } 239 return (0); 240 } 241
Indexes created Sun Sep 28 16:09:52 GMT 2025