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 * @(#)subr_log.c 7.11 (Berkeley) 3/17/91 34 */ 35 36 /* 37 * Error log buffer for kernel printf's. 38 */ 39 40 #include "param.h" 41 #include "proc.h" 42 #include "vnode.h" 43 #include "ioctl.h" 44 #include "msgbuf.h" 45 #include "file.h" 46 47 #define LOG_RDPRI (PZERO + 1) 48 49 #define LOG_ASYNC 0x04 50 #define LOG_RDWAIT 0x08 51 52 struct logsoftc { 53 int sc_state; /* see above for possibilities */ 54 struct proc *sc_selp; /* process waiting on select call */ 55 int sc_pgid; /* process/group for async I/O */ 56 } logsoftc; 57 58 int log_open; /* also used in log() */ 59 60 /*ARGSUSED*/ 61 logopen(dev, flags, mode, p) 62 dev_t dev; 63 int flags, mode; 64 struct proc *p; 65 { 66 register struct msgbuf *mbp = msgbufp; 67 68 if (log_open) 69 return (EBUSY); 70 log_open = 1; 71 logsoftc.sc_pgid = p->p_pid; /* signal process only */ 72 /* 73 * Potential race here with putchar() but since putchar should be 74 * called by autoconf, msg_magic should be initialized by the time 75 * we get here. 76 */ 77 if (mbp->msg_magic != MSG_MAGIC) { 78 register int i; 79 80 mbp->msg_magic = MSG_MAGIC; 81 mbp->msg_bufx = mbp->msg_bufr = 0; 82 for (i=0; i < MSG_BSIZE; i++) 83 mbp->msg_bufc[i] = 0; 84 } 85 return (0); 86 } 87 88 /*ARGSUSED*/ 89 logclose(dev, flag) 90 dev_t dev; 91 { 92 log_open = 0; 93 logsoftc.sc_state = 0; 94 logsoftc.sc_selp = 0; 95 } 96 97 /*ARGSUSED*/ 98 logread(dev, uio, flag) 99 dev_t dev; 100 struct uio *uio; 101 int flag; 102 { 103 register struct msgbuf *mbp = msgbufp; 104 register long l; 105 register int s; 106 int error = 0; 107 108 s = splhigh(); 109 while (mbp->msg_bufr == mbp->msg_bufx) { 110 if (flag & IO_NDELAY) { 111 splx(s); 112 return (EWOULDBLOCK); 113 } 114 logsoftc.sc_state |= LOG_RDWAIT; 115 if (error = tsleep((caddr_t)mbp, LOG_RDPRI | PCATCH, 116 "klog", 0)) { 117 splx(s); 118 return (error); 119 } 120 } 121 splx(s); 122 logsoftc.sc_state &= ~LOG_RDWAIT; 123 124 while (uio->uio_resid > 0) { 125 l = mbp->msg_bufx - mbp->msg_bufr; 126 if (l < 0) 127 l = MSG_BSIZE - mbp->msg_bufr; 128 l = MIN(l, uio->uio_resid); 129 if (l == 0) 130 break; 131 error = uiomove((caddr_t)&mbp->msg_bufc[mbp->msg_bufr], 132 (int)l, uio); 133 if (error) 134 break; 135 mbp->msg_bufr += l; 136 if (mbp->msg_bufr < 0 || mbp->msg_bufr >= MSG_BSIZE) 137 mbp->msg_bufr = 0; 138 } 139 return (error); 140 } 141 142 /*ARGSUSED*/ 143 logselect(dev, rw, p) 144 dev_t dev; 145 int rw; 146 struct proc *p; 147 { 148 int s = splhigh(); 149 150 switch (rw) { 151 152 case FREAD: 153 if (msgbufp->msg_bufr != msgbufp->msg_bufx) { 154 splx(s); 155 return (1); 156 } 157 logsoftc.sc_selp = p; 158 break; 159 } 160 splx(s); 161 return (0); 162 } 163 164 logwakeup() 165 { 166 struct proc *p; 167 168 if (!log_open) 169 return; 170 if (logsoftc.sc_selp) { 171 selwakeup(logsoftc.sc_selp, 0); 172 logsoftc.sc_selp = 0; 173 } 174 if (logsoftc.sc_state & LOG_ASYNC) { 175 if (logsoftc.sc_pgid < 0) 176 gsignal(-logsoftc.sc_pgid, SIGIO); 177 else if (p = pfind(logsoftc.sc_pgid)) 178 psignal(p, SIGIO); 179 } 180 if (logsoftc.sc_state & LOG_RDWAIT) { 181 wakeup((caddr_t)msgbufp); 182 logsoftc.sc_state &= ~LOG_RDWAIT; 183 } 184 } 185 186 /*ARGSUSED*/ 187 logioctl(dev, com, data, flag) 188 caddr_t data; 189 { 190 long l; 191 int s; 192 193 switch (com) { 194 195 /* return number of characters immediately available */ 196 case FIONREAD: 197 s = splhigh(); 198 l = msgbufp->msg_bufx - msgbufp->msg_bufr; 199 splx(s); 200 if (l < 0) 201 l += MSG_BSIZE; 202 *(off_t *)data = l; 203 break; 204 205 case FIONBIO: 206 break; 207 208 case FIOASYNC: 209 if (*(int *)data) 210 logsoftc.sc_state |= LOG_ASYNC; 211 else 212 logsoftc.sc_state &= ~LOG_ASYNC; 213 break; 214 215 case TIOCSPGRP: 216 logsoftc.sc_pgid = *(int *)data; 217 break; 218 219 case TIOCGPGRP: 220 *(int *)data = logsoftc.sc_pgid; 221 break; 222 223 default: 224 return (-1); 225 } 226 return (0); 227 } 228