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 */ 35 36 /* 37 * Error log buffer for kernel printf's. 38 */ 39 40 #include <sys/cdefs.h> 41 __FBSDID("$FreeBSD$"); 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 #include <sys/sysctl.h> 56 57 #define LOG_RDPRI (PZERO + 1) 58 59 #define LOG_ASYNC 0x04 60 #define LOG_RDWAIT 0x08 61 62 static d_open_t logopen; 63 static d_close_t logclose; 64 static d_read_t logread; 65 static d_ioctl_t logioctl; 66 static d_poll_t logpoll; 67 68 static void logtimeout(void *arg); 69 70 #define CDEV_MAJOR 7 71 static struct cdevsw log_cdevsw = { 72 .d_open = logopen, 73 .d_close = logclose, 74 .d_read = logread, 75 .d_ioctl = logioctl, 76 .d_poll = logpoll, 77 .d_name = "log", 78 .d_maj = CDEV_MAJOR, 79 }; 80 81 static struct logsoftc { 82 int sc_state; /* see above for possibilities */ 83 struct selinfo sc_selp; /* process waiting on select call */ 84 struct sigio *sc_sigio; /* information for async I/O */ 85 struct callout sc_callout; /* callout to wakeup syslog */ 86 } logsoftc; 87 88 int log_open; /* also used in log() */ 89 90 /* Times per second to check for a pending syslog wakeup. */ 91 static int log_wakeups_per_second = 5; 92 SYSCTL_INT(_kern, OID_AUTO, log_wakeups_per_second, CTLFLAG_RW, 93 &log_wakeups_per_second, 0, ""); 94 95 /*ARGSUSED*/ 96 static int 97 logopen(dev_t dev, int flags, int mode, struct thread *td) 98 { 99 if (log_open) 100 return (EBUSY); 101 log_open = 1; 102 callout_init(&logsoftc.sc_callout, 0); 103 fsetown(td->td_proc->p_pid, &logsoftc.sc_sigio); /* signal process only */ 104 if (log_wakeups_per_second < 1) { 105 printf("syslog wakeup is less than one. Adjusting to 1.\n"); 106 log_wakeups_per_second = 1; 107 } 108 callout_reset(&logsoftc.sc_callout, hz / log_wakeups_per_second, 109 logtimeout, NULL); 110 return (0); 111 } 112 113 /*ARGSUSED*/ 114 static int 115 logclose(dev_t dev, int flag, int mode, struct thread *td) 116 { 117 118 log_open = 0; 119 callout_stop(&logsoftc.sc_callout); 120 logsoftc.sc_state = 0; 121 funsetown(&logsoftc.sc_sigio); 122 return (0); 123 } 124 125 /*ARGSUSED*/ 126 static int 127 logread(dev_t dev, struct uio *uio, int flag) 128 { 129 char buf[128]; 130 struct msgbuf *mbp = msgbufp; 131 int error = 0, l, s; 132 133 s = splhigh(); 134 while (msgbuf_getcount(mbp) == 0) { 135 if (flag & IO_NDELAY) { 136 splx(s); 137 return (EWOULDBLOCK); 138 } 139 logsoftc.sc_state |= LOG_RDWAIT; 140 if ((error = tsleep(mbp, LOG_RDPRI | PCATCH, "klog", 0))) { 141 splx(s); 142 return (error); 143 } 144 } 145 splx(s); 146 logsoftc.sc_state &= ~LOG_RDWAIT; 147 148 while (uio->uio_resid > 0) { 149 l = imin(sizeof(buf), uio->uio_resid); 150 l = msgbuf_getbytes(mbp, buf, l); 151 if (l == 0) 152 break; 153 error = uiomove(buf, l, uio); 154 if (error) 155 break; 156 } 157 return (error); 158 } 159 160 /*ARGSUSED*/ 161 static int 162 logpoll(dev_t dev, int events, struct thread *td) 163 { 164 int s; 165 int revents = 0; 166 167 s = splhigh(); 168 169 if (events & (POLLIN | POLLRDNORM)) { 170 if (msgbuf_getcount(msgbufp) > 0) 171 revents |= events & (POLLIN | POLLRDNORM); 172 else 173 selrecord(td, &logsoftc.sc_selp); 174 } 175 splx(s); 176 return (revents); 177 } 178 179 static void 180 logtimeout(void *arg) 181 { 182 183 if (!log_open) 184 return; 185 if (log_wakeups_per_second < 1) { 186 printf("syslog wakeup is less than one. Adjusting to 1.\n"); 187 log_wakeups_per_second = 1; 188 } 189 if (msgbuftrigger == 0) { 190 callout_reset(&logsoftc.sc_callout, 191 hz / log_wakeups_per_second, logtimeout, NULL); 192 return; 193 } 194 msgbuftrigger = 0; 195 selwakeup(&logsoftc.sc_selp); 196 if ((logsoftc.sc_state & LOG_ASYNC) && logsoftc.sc_sigio != NULL) 197 pgsigio(&logsoftc.sc_sigio, SIGIO, 0); 198 if (logsoftc.sc_state & LOG_RDWAIT) { 199 wakeup(msgbufp); 200 logsoftc.sc_state &= ~LOG_RDWAIT; 201 } 202 callout_reset(&logsoftc.sc_callout, hz / log_wakeups_per_second, 203 logtimeout, NULL); 204 } 205 206 /*ARGSUSED*/ 207 static int 208 logioctl(dev_t dev, u_long com, caddr_t data, int flag, struct thread *td) 209 { 210 211 switch (com) { 212 213 /* return number of characters immediately available */ 214 case FIONREAD: 215 *(int *)data = msgbuf_getcount(msgbufp); 216 break; 217 218 case FIONBIO: 219 break; 220 221 case FIOASYNC: 222 if (*(int *)data) 223 logsoftc.sc_state |= LOG_ASYNC; 224 else 225 logsoftc.sc_state &= ~LOG_ASYNC; 226 break; 227 228 case FIOSETOWN: 229 return (fsetown(*(int *)data, &logsoftc.sc_sigio)); 230 231 case FIOGETOWN: 232 *(int *)data = fgetown(&logsoftc.sc_sigio); 233 break; 234 235 /* This is deprecated, FIOSETOWN should be used instead. */ 236 case TIOCSPGRP: 237 return (fsetown(-(*(int *)data), &logsoftc.sc_sigio)); 238 239 /* This is deprecated, FIOGETOWN should be used instead */ 240 case TIOCGPGRP: 241 *(int *)data = -fgetown(&logsoftc.sc_sigio); 242 break; 243 244 default: 245 return (ENOTTY); 246 } 247 return (0); 248 } 249 250 static void 251 log_drvinit(void *unused) 252 { 253 254 make_dev(&log_cdevsw, 0, UID_ROOT, GID_WHEEL, 0600, "klog"); 255 } 256 257 SYSINIT(logdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,log_drvinit,NULL) 258