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_version = D_VERSION, 73 .d_flags = D_NEEDGIANT, 74 .d_open = logopen, 75 .d_close = logclose, 76 .d_read = logread, 77 .d_ioctl = logioctl, 78 .d_poll = logpoll, 79 .d_name = "log", 80 .d_maj = CDEV_MAJOR, 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 struct callout sc_callout; /* callout to wakeup syslog */ 88 } logsoftc; 89 90 int log_open; /* also used in log() */ 91 92 /* Times per second to check for a pending syslog wakeup. */ 93 static int log_wakeups_per_second = 5; 94 SYSCTL_INT(_kern, OID_AUTO, log_wakeups_per_second, CTLFLAG_RW, 95 &log_wakeups_per_second, 0, ""); 96 97 /*ARGSUSED*/ 98 static int 99 logopen(dev_t dev, int flags, int mode, struct thread *td) 100 { 101 if (log_open) 102 return (EBUSY); 103 log_open = 1; 104 callout_init(&logsoftc.sc_callout, 0); 105 fsetown(td->td_proc->p_pid, &logsoftc.sc_sigio); /* signal process only */ 106 if (log_wakeups_per_second < 1) { 107 printf("syslog wakeup is less than one. Adjusting to 1.\n"); 108 log_wakeups_per_second = 1; 109 } 110 callout_reset(&logsoftc.sc_callout, hz / log_wakeups_per_second, 111 logtimeout, NULL); 112 return (0); 113 } 114 115 /*ARGSUSED*/ 116 static int 117 logclose(dev_t dev, int flag, int mode, struct thread *td) 118 { 119 120 log_open = 0; 121 callout_stop(&logsoftc.sc_callout); 122 logsoftc.sc_state = 0; 123 funsetown(&logsoftc.sc_sigio); 124 return (0); 125 } 126 127 /*ARGSUSED*/ 128 static int 129 logread(dev_t dev, struct uio *uio, int flag) 130 { 131 char buf[128]; 132 struct msgbuf *mbp = msgbufp; 133 int error = 0, l, s; 134 135 s = splhigh(); 136 while (msgbuf_getcount(mbp) == 0) { 137 if (flag & IO_NDELAY) { 138 splx(s); 139 return (EWOULDBLOCK); 140 } 141 logsoftc.sc_state |= LOG_RDWAIT; 142 if ((error = tsleep(mbp, LOG_RDPRI | PCATCH, "klog", 0))) { 143 splx(s); 144 return (error); 145 } 146 } 147 splx(s); 148 logsoftc.sc_state &= ~LOG_RDWAIT; 149 150 while (uio->uio_resid > 0) { 151 l = imin(sizeof(buf), uio->uio_resid); 152 l = msgbuf_getbytes(mbp, buf, l); 153 if (l == 0) 154 break; 155 error = uiomove(buf, l, uio); 156 if (error) 157 break; 158 } 159 return (error); 160 } 161 162 /*ARGSUSED*/ 163 static int 164 logpoll(dev_t dev, int events, struct thread *td) 165 { 166 int s; 167 int revents = 0; 168 169 s = splhigh(); 170 171 if (events & (POLLIN | POLLRDNORM)) { 172 if (msgbuf_getcount(msgbufp) > 0) 173 revents |= events & (POLLIN | POLLRDNORM); 174 else 175 selrecord(td, &logsoftc.sc_selp); 176 } 177 splx(s); 178 return (revents); 179 } 180 181 static void 182 logtimeout(void *arg) 183 { 184 185 if (!log_open) 186 return; 187 if (log_wakeups_per_second < 1) { 188 printf("syslog wakeup is less than one. Adjusting to 1.\n"); 189 log_wakeups_per_second = 1; 190 } 191 if (msgbuftrigger == 0) { 192 callout_reset(&logsoftc.sc_callout, 193 hz / log_wakeups_per_second, logtimeout, NULL); 194 return; 195 } 196 msgbuftrigger = 0; 197 selwakeuppri(&logsoftc.sc_selp, LOG_RDPRI); 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(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 thread *td) 211 { 212 213 switch (com) { 214 215 /* return number of characters immediately available */ 216 case FIONREAD: 217 *(int *)data = msgbuf_getcount(msgbufp); 218 break; 219 220 case FIONBIO: 221 break; 222 223 case FIOASYNC: 224 if (*(int *)data) 225 logsoftc.sc_state |= LOG_ASYNC; 226 else 227 logsoftc.sc_state &= ~LOG_ASYNC; 228 break; 229 230 case FIOSETOWN: 231 return (fsetown(*(int *)data, &logsoftc.sc_sigio)); 232 233 case FIOGETOWN: 234 *(int *)data = fgetown(&logsoftc.sc_sigio); 235 break; 236 237 /* This is deprecated, FIOSETOWN should be used instead. */ 238 case TIOCSPGRP: 239 return (fsetown(-(*(int *)data), &logsoftc.sc_sigio)); 240 241 /* This is deprecated, FIOGETOWN should be used instead */ 242 case TIOCGPGRP: 243 *(int *)data = -fgetown(&logsoftc.sc_sigio); 244 break; 245 246 default: 247 return (ENOTTY); 248 } 249 return (0); 250 } 251 252 static void 253 log_drvinit(void *unused) 254 { 255 256 make_dev(&log_cdevsw, 0, UID_ROOT, GID_WHEEL, 0600, "klog"); 257 } 258 259 SYSINIT(logdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,log_drvinit,NULL) 260