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 #include <sys/sysctl.h> 54 55 #define LOG_RDPRI (PZERO + 1) 56 57 #define LOG_ASYNC 0x04 58 #define LOG_RDWAIT 0x08 59 60 static d_open_t logopen; 61 static d_close_t logclose; 62 static d_read_t logread; 63 static d_ioctl_t logioctl; 64 static d_poll_t logpoll; 65 66 static void logtimeout(void *arg); 67 68 #define CDEV_MAJOR 7 69 static struct cdevsw log_cdevsw = { 70 /* open */ logopen, 71 /* close */ logclose, 72 /* read */ logread, 73 /* write */ nowrite, 74 /* ioctl */ logioctl, 75 /* poll */ logpoll, 76 /* mmap */ nommap, 77 /* strategy */ nostrategy, 78 /* name */ "log", 79 /* maj */ CDEV_MAJOR, 80 /* dump */ nodump, 81 /* psize */ nopsize, 82 /* flags */ 0, 83 /* bmaj */ -1 84 }; 85 86 static struct logsoftc { 87 int sc_state; /* see above for possibilities */ 88 struct selinfo sc_selp; /* process waiting on select call */ 89 struct sigio *sc_sigio; /* information for async I/O */ 90 struct callout sc_callout; /* callout to wakeup syslog */ 91 } logsoftc; 92 93 int log_open; /* also used in log() */ 94 95 /* Times per second to check for a pending syslog wakeup. */ 96 static int log_wakeups_per_second = 5; 97 SYSCTL_INT(_kern, OID_AUTO, log_wakeups_per_second, CTLFLAG_RW, 98 &log_wakeups_per_second, 0, ""); 99 100 /*ARGSUSED*/ 101 static int 102 logopen(dev_t dev, int flags, int mode, struct proc *p) 103 { 104 if (log_open) 105 return (EBUSY); 106 log_open = 1; 107 callout_init(&logsoftc.sc_callout, 0); 108 fsetown(p->p_pid, &logsoftc.sc_sigio); /* signal process only */ 109 callout_reset(&logsoftc.sc_callout, hz / log_wakeups_per_second, 110 logtimeout, NULL); 111 return (0); 112 } 113 114 /*ARGSUSED*/ 115 static int 116 logclose(dev_t dev, int flag, int mode, struct proc *p) 117 { 118 119 callout_stop(&logsoftc.sc_callout); 120 log_open = 0; 121 logsoftc.sc_state = 0; 122 funsetown(logsoftc.sc_sigio); 123 return (0); 124 } 125 126 /*ARGSUSED*/ 127 static int 128 logread(dev_t dev, struct uio *uio, int flag) 129 { 130 struct msgbuf *mbp = msgbufp; 131 long l; 132 int s; 133 int error = 0; 134 135 s = splhigh(); 136 while (mbp->msg_bufr == mbp->msg_bufx) { 137 if (flag & IO_NDELAY) { 138 splx(s); 139 return (EWOULDBLOCK); 140 } 141 logsoftc.sc_state |= LOG_RDWAIT; 142 if ((error = tsleep((caddr_t)mbp, LOG_RDPRI | PCATCH, 143 "klog", 0))) { 144 splx(s); 145 return (error); 146 } 147 } 148 splx(s); 149 logsoftc.sc_state &= ~LOG_RDWAIT; 150 151 while (uio->uio_resid > 0) { 152 l = mbp->msg_bufx - mbp->msg_bufr; 153 if (l < 0) 154 l = mbp->msg_size - mbp->msg_bufr; 155 l = min(l, uio->uio_resid); 156 if (l == 0) 157 break; 158 error = uiomove((caddr_t)msgbufp->msg_ptr + mbp->msg_bufr, 159 (int)l, uio); 160 if (error) 161 break; 162 mbp->msg_bufr += l; 163 if (mbp->msg_bufr >= mbp->msg_size) 164 mbp->msg_bufr = 0; 165 } 166 return (error); 167 } 168 169 /*ARGSUSED*/ 170 static int 171 logpoll(dev_t dev, int events, struct proc *p) 172 { 173 int s; 174 int revents = 0; 175 176 s = splhigh(); 177 178 if (events & (POLLIN | POLLRDNORM)) { 179 if (msgbufp->msg_bufr != msgbufp->msg_bufx) 180 revents |= events & (POLLIN | POLLRDNORM); 181 else 182 selrecord(p, &logsoftc.sc_selp); 183 } 184 splx(s); 185 return (revents); 186 } 187 188 static void 189 logtimeout(void *arg) 190 { 191 192 if (msgbuftrigger == 0) 193 return; 194 msgbuftrigger = 0; 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 callout_reset(&logsoftc.sc_callout, hz / log_wakeups_per_second, 205 logtimeout, NULL); 206 } 207 208 /*ARGSUSED*/ 209 static int 210 logioctl(dev_t dev, u_long com, caddr_t data, int flag, struct proc *p) 211 { 212 long l; 213 int s; 214 215 switch (com) { 216 217 /* return number of characters immediately available */ 218 case FIONREAD: 219 s = splhigh(); 220 l = msgbufp->msg_bufx - msgbufp->msg_bufr; 221 splx(s); 222 if (l < 0) 223 l += msgbufp->msg_size; 224 *(int *)data = l; 225 break; 226 227 case FIONBIO: 228 break; 229 230 case FIOASYNC: 231 if (*(int *)data) 232 logsoftc.sc_state |= LOG_ASYNC; 233 else 234 logsoftc.sc_state &= ~LOG_ASYNC; 235 break; 236 237 case FIOSETOWN: 238 return (fsetown(*(int *)data, &logsoftc.sc_sigio)); 239 240 case FIOGETOWN: 241 *(int *)data = fgetown(logsoftc.sc_sigio); 242 break; 243 244 /* This is deprecated, FIOSETOWN should be used instead. */ 245 case TIOCSPGRP: 246 return (fsetown(-(*(int *)data), &logsoftc.sc_sigio)); 247 248 /* This is deprecated, FIOGETOWN should be used instead */ 249 case TIOCGPGRP: 250 *(int *)data = -fgetown(logsoftc.sc_sigio); 251 break; 252 253 default: 254 return (ENOTTY); 255 } 256 return (0); 257 } 258 259 static void 260 log_drvinit(void *unused) 261 { 262 263 make_dev(&log_cdevsw, 0, UID_ROOT, GID_WHEEL, 0600, "klog"); 264 } 265 266 SYSINIT(logdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,log_drvinit,NULL) 267