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 1.21 1997/03/23 03:36:22 bde 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/conf.h> 44 #include <sys/proc.h> 45 #include <sys/vnode.h> 46 #include <sys/filio.h> 47 #include <sys/ttycom.h> 48 #include <sys/msgbuf.h> 49 #include <sys/fcntl.h> 50 #include <sys/signalvar.h> 51 #include <sys/kernel.h> 52 #ifdef DEVFS 53 #include <sys/devfsext.h> 54 #endif /*DEVFS*/ 55 56 #define LOG_RDPRI (PZERO + 1) 57 58 #define LOG_ASYNC 0x04 59 #define LOG_RDWAIT 0x08 60 61 static d_open_t logopen; 62 static d_close_t logclose; 63 static d_read_t logread; 64 static d_ioctl_t logioctl; 65 static d_select_t logselect; 66 67 #define CDEV_MAJOR 7 68 static struct cdevsw log_cdevsw = 69 { logopen, logclose, logread, nowrite, /*7*/ 70 logioctl, nostop, nullreset, nodevtotty,/* klog */ 71 logselect, nommap, NULL, "log", NULL, -1 }; 72 73 static struct logsoftc { 74 int sc_state; /* see above for possibilities */ 75 struct selinfo sc_selp; /* process waiting on select call */ 76 int sc_pgid; /* process/group for async I/O */ 77 } logsoftc; 78 79 int log_open; /* also used in log() */ 80 81 /*ARGSUSED*/ 82 static int 83 logopen(dev, flags, mode, p) 84 dev_t dev; 85 int flags, mode; 86 struct proc *p; 87 { 88 if (log_open) 89 return (EBUSY); 90 log_open = 1; 91 logsoftc.sc_pgid = p->p_pid; /* signal process only */ 92 return (0); 93 } 94 95 /*ARGSUSED*/ 96 static int 97 logclose(dev, flag, mode, p) 98 dev_t dev; 99 int flag, mode; 100 struct proc *p; 101 { 102 103 log_open = 0; 104 logsoftc.sc_state = 0; 105 return (0); 106 } 107 108 /*ARGSUSED*/ 109 static int 110 logread(dev, uio, flag) 111 dev_t dev; 112 struct uio *uio; 113 int flag; 114 { 115 register struct msgbuf *mbp = msgbufp; 116 register long l; 117 register int s; 118 int error = 0; 119 120 s = splhigh(); 121 while (mbp->msg_bufr == mbp->msg_bufx) { 122 if (flag & IO_NDELAY) { 123 splx(s); 124 return (EWOULDBLOCK); 125 } 126 logsoftc.sc_state |= LOG_RDWAIT; 127 if ((error = tsleep((caddr_t)mbp, LOG_RDPRI | PCATCH, 128 "klog", 0))) { 129 splx(s); 130 return (error); 131 } 132 } 133 splx(s); 134 logsoftc.sc_state &= ~LOG_RDWAIT; 135 136 while (uio->uio_resid > 0) { 137 l = mbp->msg_bufx - mbp->msg_bufr; 138 if (l < 0) 139 l = MSG_BSIZE - mbp->msg_bufr; 140 l = min(l, uio->uio_resid); 141 if (l == 0) 142 break; 143 error = uiomove((caddr_t)&mbp->msg_bufc[mbp->msg_bufr], 144 (int)l, uio); 145 if (error) 146 break; 147 mbp->msg_bufr += l; 148 if (mbp->msg_bufr >= MSG_BSIZE) 149 mbp->msg_bufr = 0; 150 } 151 return (error); 152 } 153 154 /*ARGSUSED*/ 155 static int 156 logselect(dev, rw, p) 157 dev_t dev; 158 int rw; 159 struct proc *p; 160 { 161 int s = splhigh(); 162 163 switch (rw) { 164 165 case FREAD: 166 if (msgbufp->msg_bufr != msgbufp->msg_bufx) { 167 splx(s); 168 return (1); 169 } 170 selrecord(p, &logsoftc.sc_selp); 171 break; 172 } 173 splx(s); 174 return (0); 175 } 176 177 void 178 logwakeup() 179 { 180 struct proc *p; 181 182 if (!log_open) 183 return; 184 selwakeup(&logsoftc.sc_selp); 185 if (logsoftc.sc_state & LOG_ASYNC) { 186 if (logsoftc.sc_pgid < 0) 187 gsignal(-logsoftc.sc_pgid, SIGIO); 188 else if ((p = pfind(logsoftc.sc_pgid))) 189 psignal(p, SIGIO); 190 } 191 if (logsoftc.sc_state & LOG_RDWAIT) { 192 wakeup((caddr_t)msgbufp); 193 logsoftc.sc_state &= ~LOG_RDWAIT; 194 } 195 } 196 197 /*ARGSUSED*/ 198 static int 199 logioctl(dev, com, data, flag, p) 200 dev_t dev; 201 int com; 202 caddr_t data; 203 int flag; 204 struct proc *p; 205 { 206 long l; 207 int s; 208 209 switch (com) { 210 211 /* return number of characters immediately available */ 212 case FIONREAD: 213 s = splhigh(); 214 l = msgbufp->msg_bufx - msgbufp->msg_bufr; 215 splx(s); 216 if (l < 0) 217 l += MSG_BSIZE; 218 *(int *)data = l; 219 break; 220 221 case FIONBIO: 222 break; 223 224 case FIOASYNC: 225 if (*(int *)data) 226 logsoftc.sc_state |= LOG_ASYNC; 227 else 228 logsoftc.sc_state &= ~LOG_ASYNC; 229 break; 230 231 case TIOCSPGRP: 232 logsoftc.sc_pgid = *(int *)data; 233 break; 234 235 case TIOCGPGRP: 236 *(int *)data = logsoftc.sc_pgid; 237 break; 238 239 default: 240 return (ENOTTY); 241 } 242 return (0); 243 } 244 245 static log_devsw_installed = 0; 246 #ifdef DEVFS 247 static void *log_devfs_token; 248 #endif 249 250 static void 251 log_drvinit(void *unused) 252 { 253 dev_t dev; 254 255 if( ! log_devsw_installed ) { 256 dev = makedev(CDEV_MAJOR,0); 257 cdevsw_add(&dev,&log_cdevsw,NULL); 258 log_devsw_installed = 1; 259 #ifdef DEVFS 260 log_devfs_token = devfs_add_devswf(&log_cdevsw, 0, DV_CHR, 261 UID_ROOT, GID_WHEEL, 0600, 262 "klog"); 263 #endif 264 } 265 } 266 267 SYSINIT(logdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,log_drvinit,NULL) 268 269 270