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: subr_log.c,v 1.9 1995/08/07 07:58:17 davidg 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/signalvar.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 if (log_open) 71 return (EBUSY); 72 log_open = 1; 73 logsoftc.sc_pgid = p->p_pid; /* signal process only */ 74 return (0); 75 } 76 77 /*ARGSUSED*/ 78 int 79 logclose(dev, flag, mode, p) 80 dev_t dev; 81 int flag, mode; 82 struct proc *p; 83 { 84 85 log_open = 0; 86 logsoftc.sc_state = 0; 87 return (0); 88 } 89 90 /*ARGSUSED*/ 91 int 92 logread(dev, uio, flag) 93 dev_t dev; 94 struct uio *uio; 95 int flag; 96 { 97 register struct msgbuf *mbp = msgbufp; 98 register long l; 99 register int s; 100 int error = 0; 101 102 s = splhigh(); 103 while (mbp->msg_bufr == mbp->msg_bufx) { 104 if (flag & IO_NDELAY) { 105 splx(s); 106 return (EWOULDBLOCK); 107 } 108 logsoftc.sc_state |= LOG_RDWAIT; 109 if ((error = tsleep((caddr_t)mbp, LOG_RDPRI | PCATCH, 110 "klog", 0))) { 111 splx(s); 112 return (error); 113 } 114 } 115 splx(s); 116 logsoftc.sc_state &= ~LOG_RDWAIT; 117 118 while (uio->uio_resid > 0) { 119 l = mbp->msg_bufx - mbp->msg_bufr; 120 if (l < 0) 121 l = MSG_BSIZE - mbp->msg_bufr; 122 l = min(l, uio->uio_resid); 123 if (l == 0) 124 break; 125 error = uiomove((caddr_t)&mbp->msg_bufc[mbp->msg_bufr], 126 (int)l, uio); 127 if (error) 128 break; 129 mbp->msg_bufr += l; 130 if (mbp->msg_bufr >= MSG_BSIZE) 131 mbp->msg_bufr = 0; 132 } 133 return (error); 134 } 135 136 /*ARGSUSED*/ 137 int 138 logselect(dev, rw, p) 139 dev_t dev; 140 int rw; 141 struct proc *p; 142 { 143 int s = splhigh(); 144 145 switch (rw) { 146 147 case FREAD: 148 if (msgbufp->msg_bufr != msgbufp->msg_bufx) { 149 splx(s); 150 return (1); 151 } 152 selrecord(p, &logsoftc.sc_selp); 153 break; 154 } 155 splx(s); 156 return (0); 157 } 158 159 void 160 logwakeup() 161 { 162 struct proc *p; 163 164 if (!log_open) 165 return; 166 selwakeup(&logsoftc.sc_selp); 167 if (logsoftc.sc_state & LOG_ASYNC) { 168 if (logsoftc.sc_pgid < 0) 169 gsignal(-logsoftc.sc_pgid, SIGIO); 170 else if ((p = pfind(logsoftc.sc_pgid))) 171 psignal(p, SIGIO); 172 } 173 if (logsoftc.sc_state & LOG_RDWAIT) { 174 wakeup((caddr_t)msgbufp); 175 logsoftc.sc_state &= ~LOG_RDWAIT; 176 } 177 } 178 179 /*ARGSUSED*/ 180 int 181 logioctl(dev, com, data, flag, p) 182 dev_t dev; 183 int com; 184 caddr_t data; 185 int flag; 186 struct proc *p; 187 { 188 long l; 189 int s; 190 191 switch (com) { 192 193 /* return number of characters immediately available */ 194 case FIONREAD: 195 s = splhigh(); 196 l = msgbufp->msg_bufx - msgbufp->msg_bufr; 197 splx(s); 198 if (l < 0) 199 l += MSG_BSIZE; 200 *(int *)data = l; 201 break; 202 203 case FIONBIO: 204 break; 205 206 case FIOASYNC: 207 if (*(int *)data) 208 logsoftc.sc_state |= LOG_ASYNC; 209 else 210 logsoftc.sc_state &= ~LOG_ASYNC; 211 break; 212 213 case TIOCSPGRP: 214 logsoftc.sc_pgid = *(int *)data; 215 break; 216 217 case TIOCGPGRP: 218 *(int *)data = logsoftc.sc_pgid; 219 break; 220 221 default: 222 return (ENOTTY); 223 } 224 return (0); 225 } 226