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 1.35 1999/05/30 16:52:56 phk Exp $ 35 */ 36 37 /* 38 * Error log buffer for kernel printf's. 39 */ 40 41 #include "opt_devfs.h" 42 43 #include <sys/param.h> 44 #include <sys/systm.h> 45 #include <sys/conf.h> 46 #include <sys/proc.h> 47 #include <sys/vnode.h> 48 #include <sys/filio.h> 49 #include <sys/ttycom.h> 50 #include <sys/msgbuf.h> 51 #include <sys/signalvar.h> 52 #include <sys/kernel.h> 53 #include <sys/poll.h> 54 #include <sys/filedesc.h> 55 #ifdef DEVFS 56 #include <sys/devfsext.h> 57 #endif /*DEVFS*/ 58 59 #define LOG_RDPRI (PZERO + 1) 60 61 #define LOG_ASYNC 0x04 62 #define LOG_RDWAIT 0x08 63 64 static d_open_t logopen; 65 static d_close_t logclose; 66 static d_read_t logread; 67 static d_ioctl_t logioctl; 68 static d_poll_t logpoll; 69 70 #define CDEV_MAJOR 7 71 static struct cdevsw log_cdevsw = { 72 /* open */ logopen, 73 /* close */ logclose, 74 /* read */ logread, 75 /* write */ nowrite, 76 /* ioctl */ logioctl, 77 /* stop */ nostop, 78 /* reset */ noreset, 79 /* devtotty */ nodevtotty, 80 /* poll */ logpoll, 81 /* mmap */ nommap, 82 /* strategy */ nostrategy, 83 /* name */ "log", 84 /* parms */ noparms, 85 /* maj */ CDEV_MAJOR, 86 /* dump */ nodump, 87 /* psize */ nopsize, 88 /* flags */ 0, 89 /* maxio */ 0, 90 /* bmaj */ -1 91 }; 92 93 static struct logsoftc { 94 int sc_state; /* see above for possibilities */ 95 struct selinfo sc_selp; /* process waiting on select call */ 96 struct sigio *sc_sigio; /* information for async I/O */ 97 } logsoftc; 98 99 int log_open; /* also used in log() */ 100 101 /*ARGSUSED*/ 102 static int 103 logopen(dev, flags, mode, p) 104 dev_t dev; 105 int flags, mode; 106 struct proc *p; 107 { 108 if (log_open) 109 return (EBUSY); 110 log_open = 1; 111 fsetown(p->p_pid, &logsoftc.sc_sigio); /* signal process only */ 112 return (0); 113 } 114 115 /*ARGSUSED*/ 116 static int 117 logclose(dev, flag, mode, p) 118 dev_t dev; 119 int flag, mode; 120 struct proc *p; 121 { 122 123 log_open = 0; 124 logsoftc.sc_state = 0; 125 funsetown(logsoftc.sc_sigio); 126 return (0); 127 } 128 129 /*ARGSUSED*/ 130 static int 131 logread(dev, uio, flag) 132 dev_t dev; 133 struct uio *uio; 134 int flag; 135 { 136 register struct msgbuf *mbp = msgbufp; 137 register long l; 138 register int s; 139 int error = 0; 140 141 s = splhigh(); 142 while (mbp->msg_bufr == mbp->msg_bufx) { 143 if (flag & IO_NDELAY) { 144 splx(s); 145 return (EWOULDBLOCK); 146 } 147 logsoftc.sc_state |= LOG_RDWAIT; 148 if ((error = tsleep((caddr_t)mbp, LOG_RDPRI | PCATCH, 149 "klog", 0))) { 150 splx(s); 151 return (error); 152 } 153 } 154 splx(s); 155 logsoftc.sc_state &= ~LOG_RDWAIT; 156 157 while (uio->uio_resid > 0) { 158 l = mbp->msg_bufx - mbp->msg_bufr; 159 if (l < 0) 160 l = mbp->msg_size - mbp->msg_bufr; 161 l = min(l, uio->uio_resid); 162 if (l == 0) 163 break; 164 error = uiomove((caddr_t)msgbufp->msg_ptr + mbp->msg_bufr, 165 (int)l, uio); 166 if (error) 167 break; 168 mbp->msg_bufr += l; 169 if (mbp->msg_bufr >= mbp->msg_size) 170 mbp->msg_bufr = 0; 171 } 172 return (error); 173 } 174 175 /*ARGSUSED*/ 176 static int 177 logpoll(dev, events, p) 178 dev_t dev; 179 int events; 180 struct proc *p; 181 { 182 int s; 183 int revents = 0; 184 185 s = splhigh(); 186 187 if (events & (POLLIN | POLLRDNORM)) { 188 if (msgbufp->msg_bufr != msgbufp->msg_bufx) 189 revents |= events & (POLLIN | POLLRDNORM); 190 else 191 selrecord(p, &logsoftc.sc_selp); 192 } 193 splx(s); 194 return (revents); 195 } 196 197 void 198 logwakeup() 199 { 200 if (!log_open) 201 return; 202 selwakeup(&logsoftc.sc_selp); 203 if ((logsoftc.sc_state & LOG_ASYNC) && logsoftc.sc_sigio != NULL) 204 pgsigio(logsoftc.sc_sigio, SIGIO, 0); 205 if (logsoftc.sc_state & LOG_RDWAIT) { 206 wakeup((caddr_t)msgbufp); 207 logsoftc.sc_state &= ~LOG_RDWAIT; 208 } 209 } 210 211 /*ARGSUSED*/ 212 static int 213 logioctl(dev, com, data, flag, p) 214 dev_t dev; 215 u_long com; 216 caddr_t data; 217 int flag; 218 struct proc *p; 219 { 220 long l; 221 int s; 222 223 switch (com) { 224 225 /* return number of characters immediately available */ 226 case FIONREAD: 227 s = splhigh(); 228 l = msgbufp->msg_bufx - msgbufp->msg_bufr; 229 splx(s); 230 if (l < 0) 231 l += msgbufp->msg_size; 232 *(int *)data = l; 233 break; 234 235 case FIONBIO: 236 break; 237 238 case FIOASYNC: 239 if (*(int *)data) 240 logsoftc.sc_state |= LOG_ASYNC; 241 else 242 logsoftc.sc_state &= ~LOG_ASYNC; 243 break; 244 245 case FIOSETOWN: 246 return (fsetown(*(int *)data, &logsoftc.sc_sigio)); 247 248 case FIOGETOWN: 249 *(int *)data = fgetown(logsoftc.sc_sigio); 250 break; 251 252 /* This is deprecated, FIOSETOWN should be used instead. */ 253 case TIOCSPGRP: 254 return (fsetown(-(*(int *)data), &logsoftc.sc_sigio)); 255 256 /* This is deprecated, FIOGETOWN should be used instead */ 257 case TIOCGPGRP: 258 *(int *)data = -fgetown(logsoftc.sc_sigio); 259 break; 260 261 default: 262 return (ENOTTY); 263 } 264 return (0); 265 } 266 267 static int log_devsw_installed; 268 #ifdef DEVFS 269 static void *log_devfs_token; 270 #endif 271 272 static void log_drvinit __P((void *unused)); 273 static void 274 log_drvinit(unused) 275 void *unused; 276 { 277 278 if( ! log_devsw_installed ) { 279 cdevsw_add(&log_cdevsw); 280 log_devsw_installed = 1; 281 #ifdef DEVFS 282 log_devfs_token = devfs_add_devswf(&log_cdevsw, 0, DV_CHR, 283 UID_ROOT, GID_WHEEL, 0600, 284 "klog"); 285 #endif 286 } 287 } 288 289 SYSINIT(logdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,log_drvinit,NULL) 290