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 .d_open = logopen, 71 .d_close = logclose, 72 .d_read = logread, 73 .d_ioctl = logioctl, 74 .d_poll = logpoll, 75 .d_name = "log", 76 .d_maj = CDEV_MAJOR, 77 }; 78 79 static struct logsoftc { 80 int sc_state; /* see above for possibilities */ 81 struct selinfo sc_selp; /* process waiting on select call */ 82 struct sigio *sc_sigio; /* information for async I/O */ 83 struct callout sc_callout; /* callout to wakeup syslog */ 84 } logsoftc; 85 86 int log_open; /* also used in log() */ 87 88 /* Times per second to check for a pending syslog wakeup. */ 89 static int log_wakeups_per_second = 5; 90 SYSCTL_INT(_kern, OID_AUTO, log_wakeups_per_second, CTLFLAG_RW, 91 &log_wakeups_per_second, 0, ""); 92 93 /*ARGSUSED*/ 94 static int 95 logopen(dev_t dev, int flags, int mode, struct thread *td) 96 { 97 if (log_open) 98 return (EBUSY); 99 log_open = 1; 100 callout_init(&logsoftc.sc_callout, 0); 101 fsetown(td->td_proc->p_pid, &logsoftc.sc_sigio); /* signal process only */ 102 callout_reset(&logsoftc.sc_callout, hz / log_wakeups_per_second, 103 logtimeout, NULL); 104 return (0); 105 } 106 107 /*ARGSUSED*/ 108 static int 109 logclose(dev_t dev, int flag, int mode, struct thread *td) 110 { 111 112 log_open = 0; 113 callout_stop(&logsoftc.sc_callout); 114 logsoftc.sc_state = 0; 115 funsetown(&logsoftc.sc_sigio); 116 return (0); 117 } 118 119 /*ARGSUSED*/ 120 static int 121 logread(dev_t dev, struct uio *uio, int flag) 122 { 123 struct msgbuf *mbp = msgbufp; 124 int error = 0, l, s; 125 126 s = splhigh(); 127 while (mbp->msg_bufr == mbp->msg_bufx) { 128 if (flag & IO_NDELAY) { 129 splx(s); 130 return (EWOULDBLOCK); 131 } 132 logsoftc.sc_state |= LOG_RDWAIT; 133 if ((error = tsleep(mbp, LOG_RDPRI | PCATCH, "klog", 0))) { 134 splx(s); 135 return (error); 136 } 137 } 138 splx(s); 139 logsoftc.sc_state &= ~LOG_RDWAIT; 140 141 while (uio->uio_resid > 0) { 142 l = mbp->msg_bufx - mbp->msg_bufr; 143 if (l < 0) 144 l = mbp->msg_size - mbp->msg_bufr; 145 l = imin(l, uio->uio_resid); 146 if (l == 0) 147 break; 148 error = uiomove((char *)msgbufp->msg_ptr + mbp->msg_bufr, 149 l, uio); 150 if (error) 151 break; 152 mbp->msg_bufr += l; 153 if (mbp->msg_bufr >= mbp->msg_size) 154 mbp->msg_bufr = 0; 155 } 156 return (error); 157 } 158 159 /*ARGSUSED*/ 160 static int 161 logpoll(dev_t dev, int events, struct thread *td) 162 { 163 int s; 164 int revents = 0; 165 166 s = splhigh(); 167 168 if (events & (POLLIN | POLLRDNORM)) { 169 if (msgbufp->msg_bufr != msgbufp->msg_bufx) 170 revents |= events & (POLLIN | POLLRDNORM); 171 else 172 selrecord(td, &logsoftc.sc_selp); 173 } 174 splx(s); 175 return (revents); 176 } 177 178 static void 179 logtimeout(void *arg) 180 { 181 182 if (!log_open) 183 return; 184 if (msgbuftrigger == 0) { 185 callout_reset(&logsoftc.sc_callout, 186 hz / log_wakeups_per_second, logtimeout, NULL); 187 return; 188 } 189 msgbuftrigger = 0; 190 selwakeup(&logsoftc.sc_selp); 191 if ((logsoftc.sc_state & LOG_ASYNC) && logsoftc.sc_sigio != NULL) 192 pgsigio(&logsoftc.sc_sigio, SIGIO, 0); 193 if (logsoftc.sc_state & LOG_RDWAIT) { 194 wakeup(msgbufp); 195 logsoftc.sc_state &= ~LOG_RDWAIT; 196 } 197 callout_reset(&logsoftc.sc_callout, hz / log_wakeups_per_second, 198 logtimeout, NULL); 199 } 200 201 /*ARGSUSED*/ 202 static int 203 logioctl(dev_t dev, u_long com, caddr_t data, int flag, struct thread *td) 204 { 205 int l, s; 206 207 switch (com) { 208 209 /* return number of characters immediately available */ 210 case FIONREAD: 211 s = splhigh(); 212 l = msgbufp->msg_bufx - msgbufp->msg_bufr; 213 splx(s); 214 if (l < 0) 215 l += msgbufp->msg_size; 216 *(int *)data = l; 217 break; 218 219 case FIONBIO: 220 break; 221 222 case FIOASYNC: 223 if (*(int *)data) 224 logsoftc.sc_state |= LOG_ASYNC; 225 else 226 logsoftc.sc_state &= ~LOG_ASYNC; 227 break; 228 229 case FIOSETOWN: 230 return (fsetown(*(int *)data, &logsoftc.sc_sigio)); 231 232 case FIOGETOWN: 233 *(int *)data = fgetown(&logsoftc.sc_sigio); 234 break; 235 236 /* This is deprecated, FIOSETOWN should be used instead. */ 237 case TIOCSPGRP: 238 return (fsetown(-(*(int *)data), &logsoftc.sc_sigio)); 239 240 /* This is deprecated, FIOGETOWN should be used instead */ 241 case TIOCGPGRP: 242 *(int *)data = -fgetown(&logsoftc.sc_sigio); 243 break; 244 245 default: 246 return (ENOTTY); 247 } 248 return (0); 249 } 250 251 static void 252 log_drvinit(void *unused) 253 { 254 255 make_dev(&log_cdevsw, 0, UID_ROOT, GID_WHEEL, 0600, "klog"); 256 } 257 258 SYSINIT(logdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,log_drvinit,NULL) 259