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 * @(#)subr_log.c 8.1 (Berkeley) 6/10/93 34 * $Id$ 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, mode; 96 struct proc *p; 97 { 98 99 log_open = 0; 100 logsoftc.sc_state = 0; 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, p) 196 dev_t dev; 197 int com; 198 caddr_t data; 199 int flag; 200 struct proc *p; 201 { 202 long l; 203 int s; 204 205 switch (com) { 206 207 /* return number of characters immediately available */ 208 case FIONREAD: 209 s = splhigh(); 210 l = msgbufp->msg_bufx - msgbufp->msg_bufr; 211 splx(s); 212 if (l < 0) 213 l += MSG_BSIZE; 214 *(int *)data = l; 215 break; 216 217 case FIONBIO: 218 break; 219 220 case FIOASYNC: 221 if (*(int *)data) 222 logsoftc.sc_state |= LOG_ASYNC; 223 else 224 logsoftc.sc_state &= ~LOG_ASYNC; 225 break; 226 227 case TIOCSPGRP: 228 logsoftc.sc_pgid = *(int *)data; 229 break; 230 231 case TIOCGPGRP: 232 *(int *)data = logsoftc.sc_pgid; 233 break; 234 235 default: 236 return (-1); 237 } 238 return (0); 239 } 240