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 1.36 1999/05/31 11:27:35 phk 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/signalvar.h> 50 #include <sys/kernel.h> 51 #include <sys/poll.h> 52 #include <sys/filedesc.h> 53 54 #define LOG_RDPRI (PZERO + 1) 55 56 #define LOG_ASYNC 0x04 57 #define LOG_RDWAIT 0x08 58 59 static d_open_t logopen; 60 static d_close_t logclose; 61 static d_read_t logread; 62 static d_ioctl_t logioctl; 63 static d_poll_t logpoll; 64 65 #define CDEV_MAJOR 7 66 static struct cdevsw log_cdevsw = { 67 /* open */ logopen, 68 /* close */ logclose, 69 /* read */ logread, 70 /* write */ nowrite, 71 /* ioctl */ logioctl, 72 /* stop */ nostop, 73 /* reset */ noreset, 74 /* devtotty */ nodevtotty, 75 /* poll */ logpoll, 76 /* mmap */ nommap, 77 /* strategy */ nostrategy, 78 /* name */ "log", 79 /* parms */ noparms, 80 /* maj */ CDEV_MAJOR, 81 /* dump */ nodump, 82 /* psize */ nopsize, 83 /* flags */ 0, 84 /* maxio */ 0, 85 /* bmaj */ -1 86 }; 87 88 static struct logsoftc { 89 int sc_state; /* see above for possibilities */ 90 struct selinfo sc_selp; /* process waiting on select call */ 91 struct sigio *sc_sigio; /* information for async I/O */ 92 } logsoftc; 93 94 int log_open; /* also used in log() */ 95 96 /*ARGSUSED*/ 97 static int 98 logopen(dev, flags, mode, p) 99 dev_t dev; 100 int flags, mode; 101 struct proc *p; 102 { 103 if (log_open) 104 return (EBUSY); 105 log_open = 1; 106 fsetown(p->p_pid, &logsoftc.sc_sigio); /* signal process only */ 107 return (0); 108 } 109 110 /*ARGSUSED*/ 111 static int 112 logclose(dev, flag, mode, p) 113 dev_t dev; 114 int flag, mode; 115 struct proc *p; 116 { 117 118 log_open = 0; 119 logsoftc.sc_state = 0; 120 funsetown(logsoftc.sc_sigio); 121 return (0); 122 } 123 124 /*ARGSUSED*/ 125 static int 126 logread(dev, uio, flag) 127 dev_t dev; 128 struct uio *uio; 129 int flag; 130 { 131 register struct msgbuf *mbp = msgbufp; 132 register long l; 133 register int s; 134 int error = 0; 135 136 s = splhigh(); 137 while (mbp->msg_bufr == mbp->msg_bufx) { 138 if (flag & IO_NDELAY) { 139 splx(s); 140 return (EWOULDBLOCK); 141 } 142 logsoftc.sc_state |= LOG_RDWAIT; 143 if ((error = tsleep((caddr_t)mbp, LOG_RDPRI | PCATCH, 144 "klog", 0))) { 145 splx(s); 146 return (error); 147 } 148 } 149 splx(s); 150 logsoftc.sc_state &= ~LOG_RDWAIT; 151 152 while (uio->uio_resid > 0) { 153 l = mbp->msg_bufx - mbp->msg_bufr; 154 if (l < 0) 155 l = mbp->msg_size - mbp->msg_bufr; 156 l = min(l, uio->uio_resid); 157 if (l == 0) 158 break; 159 error = uiomove((caddr_t)msgbufp->msg_ptr + mbp->msg_bufr, 160 (int)l, uio); 161 if (error) 162 break; 163 mbp->msg_bufr += l; 164 if (mbp->msg_bufr >= mbp->msg_size) 165 mbp->msg_bufr = 0; 166 } 167 return (error); 168 } 169 170 /*ARGSUSED*/ 171 static int 172 logpoll(dev, events, p) 173 dev_t dev; 174 int events; 175 struct proc *p; 176 { 177 int s; 178 int revents = 0; 179 180 s = splhigh(); 181 182 if (events & (POLLIN | POLLRDNORM)) { 183 if (msgbufp->msg_bufr != msgbufp->msg_bufx) 184 revents |= events & (POLLIN | POLLRDNORM); 185 else 186 selrecord(p, &logsoftc.sc_selp); 187 } 188 splx(s); 189 return (revents); 190 } 191 192 void 193 logwakeup() 194 { 195 if (!log_open) 196 return; 197 selwakeup(&logsoftc.sc_selp); 198 if ((logsoftc.sc_state & LOG_ASYNC) && logsoftc.sc_sigio != NULL) 199 pgsigio(logsoftc.sc_sigio, SIGIO, 0); 200 if (logsoftc.sc_state & LOG_RDWAIT) { 201 wakeup((caddr_t)msgbufp); 202 logsoftc.sc_state &= ~LOG_RDWAIT; 203 } 204 } 205 206 /*ARGSUSED*/ 207 static int 208 logioctl(dev, com, data, flag, p) 209 dev_t dev; 210 u_long com; 211 caddr_t data; 212 int flag; 213 struct proc *p; 214 { 215 long l; 216 int s; 217 218 switch (com) { 219 220 /* return number of characters immediately available */ 221 case FIONREAD: 222 s = splhigh(); 223 l = msgbufp->msg_bufx - msgbufp->msg_bufr; 224 splx(s); 225 if (l < 0) 226 l += msgbufp->msg_size; 227 *(int *)data = l; 228 break; 229 230 case FIONBIO: 231 break; 232 233 case FIOASYNC: 234 if (*(int *)data) 235 logsoftc.sc_state |= LOG_ASYNC; 236 else 237 logsoftc.sc_state &= ~LOG_ASYNC; 238 break; 239 240 case FIOSETOWN: 241 return (fsetown(*(int *)data, &logsoftc.sc_sigio)); 242 243 case FIOGETOWN: 244 *(int *)data = fgetown(logsoftc.sc_sigio); 245 break; 246 247 /* This is deprecated, FIOSETOWN should be used instead. */ 248 case TIOCSPGRP: 249 return (fsetown(-(*(int *)data), &logsoftc.sc_sigio)); 250 251 /* This is deprecated, FIOGETOWN should be used instead */ 252 case TIOCGPGRP: 253 *(int *)data = -fgetown(logsoftc.sc_sigio); 254 break; 255 256 default: 257 return (ENOTTY); 258 } 259 return (0); 260 } 261 262 263 static void log_drvinit __P((void *unused)); 264 265 static void 266 log_drvinit(unused) 267 void *unused; 268 { 269 make_dev(&log_cdevsw, 0, UID_ROOT, GID_WHEEL, 0600, "klog"); 270 } 271 272 SYSINIT(logdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,log_drvinit,NULL) 273