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 struct msgbuf *mbp = msgbufp; 130 int error = 0, l, s; 131 132 s = splhigh(); 133 while (mbp->msg_bufr == mbp->msg_bufx) { 134 if (flag & IO_NDELAY) { 135 splx(s); 136 return (EWOULDBLOCK); 137 } 138 logsoftc.sc_state |= LOG_RDWAIT; 139 if ((error = tsleep(mbp, LOG_RDPRI | PCATCH, "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 = imin(l, uio->uio_resid); 152 if (l == 0) 153 break; 154 error = uiomove((char *)msgbufp->msg_ptr + mbp->msg_bufr, 155 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_t dev, int events, struct thread *td) 168 { 169 int s; 170 int revents = 0; 171 172 s = splhigh(); 173 174 if (events & (POLLIN | POLLRDNORM)) { 175 if (msgbufp->msg_bufr != msgbufp->msg_bufx) 176 revents |= events & (POLLIN | POLLRDNORM); 177 else 178 selrecord(td, &logsoftc.sc_selp); 179 } 180 splx(s); 181 return (revents); 182 } 183 184 static void 185 logtimeout(void *arg) 186 { 187 188 if (!log_open) 189 return; 190 if (log_wakeups_per_second < 1) { 191 printf("syslog wakeup is less than one. Adjusting to 1.\n"); 192 log_wakeups_per_second = 1; 193 } 194 if (msgbuftrigger == 0) { 195 callout_reset(&logsoftc.sc_callout, 196 hz / log_wakeups_per_second, logtimeout, NULL); 197 return; 198 } 199 msgbuftrigger = 0; 200 selwakeup(&logsoftc.sc_selp); 201 if ((logsoftc.sc_state & LOG_ASYNC) && logsoftc.sc_sigio != NULL) 202 pgsigio(&logsoftc.sc_sigio, SIGIO, 0); 203 if (logsoftc.sc_state & LOG_RDWAIT) { 204 wakeup(msgbufp); 205 logsoftc.sc_state &= ~LOG_RDWAIT; 206 } 207 callout_reset(&logsoftc.sc_callout, hz / log_wakeups_per_second, 208 logtimeout, NULL); 209 } 210 211 /*ARGSUSED*/ 212 static int 213 logioctl(dev_t dev, u_long com, caddr_t data, int flag, struct thread *td) 214 { 215 int l, s; 216 217 switch (com) { 218 219 /* return number of characters immediately available */ 220 case FIONREAD: 221 s = splhigh(); 222 l = msgbufp->msg_bufx - msgbufp->msg_bufr; 223 splx(s); 224 if (l < 0) 225 l += msgbufp->msg_size; 226 *(int *)data = l; 227 break; 228 229 case FIONBIO: 230 break; 231 232 case FIOASYNC: 233 if (*(int *)data) 234 logsoftc.sc_state |= LOG_ASYNC; 235 else 236 logsoftc.sc_state &= ~LOG_ASYNC; 237 break; 238 239 case FIOSETOWN: 240 return (fsetown(*(int *)data, &logsoftc.sc_sigio)); 241 242 case FIOGETOWN: 243 *(int *)data = fgetown(&logsoftc.sc_sigio); 244 break; 245 246 /* This is deprecated, FIOSETOWN should be used instead. */ 247 case TIOCSPGRP: 248 return (fsetown(-(*(int *)data), &logsoftc.sc_sigio)); 249 250 /* This is deprecated, FIOGETOWN should be used instead */ 251 case TIOCGPGRP: 252 *(int *)data = -fgetown(&logsoftc.sc_sigio); 253 break; 254 255 default: 256 return (ENOTTY); 257 } 258 return (0); 259 } 260 261 static void 262 log_drvinit(void *unused) 263 { 264 265 make_dev(&log_cdevsw, 0, UID_ROOT, GID_WHEEL, 0600, "klog"); 266 } 267 268 SYSINIT(logdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,log_drvinit,NULL) 269