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