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 * 4. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * 29 * @(#)subr_log.c 8.1 (Berkeley) 6/10/93 30 */ 31 32 /* 33 * Error log buffer for kernel printf's. 34 */ 35 36 #include <sys/cdefs.h> 37 __FBSDID("$FreeBSD$"); 38 39 #include <sys/param.h> 40 #include <sys/systm.h> 41 #include <sys/conf.h> 42 #include <sys/proc.h> 43 #include <sys/vnode.h> 44 #include <sys/filio.h> 45 #include <sys/ttycom.h> 46 #include <sys/msgbuf.h> 47 #include <sys/signalvar.h> 48 #include <sys/kernel.h> 49 #include <sys/poll.h> 50 #include <sys/filedesc.h> 51 #include <sys/sysctl.h> 52 53 #define LOG_RDPRI (PZERO + 1) 54 55 #define LOG_ASYNC 0x04 56 #define LOG_RDWAIT 0x08 57 58 static d_open_t logopen; 59 static d_close_t logclose; 60 static d_read_t logread; 61 static d_ioctl_t logioctl; 62 static d_poll_t logpoll; 63 64 static void logtimeout(void *arg); 65 66 static struct cdevsw log_cdevsw = { 67 .d_version = D_VERSION, 68 .d_flags = D_NEEDGIANT, 69 .d_open = logopen, 70 .d_close = logclose, 71 .d_read = logread, 72 .d_ioctl = logioctl, 73 .d_poll = logpoll, 74 .d_name = "log", 75 }; 76 77 static struct logsoftc { 78 int sc_state; /* see above for possibilities */ 79 struct selinfo sc_selp; /* process waiting on select call */ 80 struct sigio *sc_sigio; /* information for async I/O */ 81 struct callout sc_callout; /* callout to wakeup syslog */ 82 } logsoftc; 83 84 int log_open; /* also used in log() */ 85 86 /* Times per second to check for a pending syslog wakeup. */ 87 static int log_wakeups_per_second = 5; 88 SYSCTL_INT(_kern, OID_AUTO, log_wakeups_per_second, CTLFLAG_RW, 89 &log_wakeups_per_second, 0, ""); 90 91 /*ARGSUSED*/ 92 static int 93 logopen(struct cdev *dev, int flags, int mode, struct thread *td) 94 { 95 if (log_open) 96 return (EBUSY); 97 log_open = 1; 98 callout_init(&logsoftc.sc_callout, 0); 99 fsetown(td->td_proc->p_pid, &logsoftc.sc_sigio); /* signal process only */ 100 if (log_wakeups_per_second < 1) { 101 printf("syslog wakeup is less than one. Adjusting to 1.\n"); 102 log_wakeups_per_second = 1; 103 } 104 callout_reset(&logsoftc.sc_callout, hz / log_wakeups_per_second, 105 logtimeout, NULL); 106 return (0); 107 } 108 109 /*ARGSUSED*/ 110 static int 111 logclose(struct cdev *dev, int flag, int mode, struct thread *td) 112 { 113 114 log_open = 0; 115 callout_stop(&logsoftc.sc_callout); 116 logsoftc.sc_state = 0; 117 funsetown(&logsoftc.sc_sigio); 118 return (0); 119 } 120 121 /*ARGSUSED*/ 122 static int 123 logread(struct cdev *dev, struct uio *uio, int flag) 124 { 125 char buf[128]; 126 struct msgbuf *mbp = msgbufp; 127 int error = 0, l, s; 128 129 s = splhigh(); 130 while (msgbuf_getcount(mbp) == 0) { 131 if (flag & IO_NDELAY) { 132 splx(s); 133 return (EWOULDBLOCK); 134 } 135 logsoftc.sc_state |= LOG_RDWAIT; 136 if ((error = tsleep(mbp, LOG_RDPRI | PCATCH, "klog", 0))) { 137 splx(s); 138 return (error); 139 } 140 } 141 splx(s); 142 logsoftc.sc_state &= ~LOG_RDWAIT; 143 144 while (uio->uio_resid > 0) { 145 l = imin(sizeof(buf), uio->uio_resid); 146 l = msgbuf_getbytes(mbp, buf, l); 147 if (l == 0) 148 break; 149 error = uiomove(buf, l, uio); 150 if (error) 151 break; 152 } 153 return (error); 154 } 155 156 /*ARGSUSED*/ 157 static int 158 logpoll(struct cdev *dev, int events, struct thread *td) 159 { 160 int s; 161 int revents = 0; 162 163 s = splhigh(); 164 165 if (events & (POLLIN | POLLRDNORM)) { 166 if (msgbuf_getcount(msgbufp) > 0) 167 revents |= events & (POLLIN | POLLRDNORM); 168 else 169 selrecord(td, &logsoftc.sc_selp); 170 } 171 splx(s); 172 return (revents); 173 } 174 175 static void 176 logtimeout(void *arg) 177 { 178 179 if (!log_open) 180 return; 181 if (log_wakeups_per_second < 1) { 182 printf("syslog wakeup is less than one. Adjusting to 1.\n"); 183 log_wakeups_per_second = 1; 184 } 185 if (msgbuftrigger == 0) { 186 callout_reset(&logsoftc.sc_callout, 187 hz / log_wakeups_per_second, logtimeout, NULL); 188 return; 189 } 190 msgbuftrigger = 0; 191 selwakeuppri(&logsoftc.sc_selp, LOG_RDPRI); 192 if ((logsoftc.sc_state & LOG_ASYNC) && logsoftc.sc_sigio != NULL) 193 pgsigio(&logsoftc.sc_sigio, SIGIO, 0); 194 if (logsoftc.sc_state & LOG_RDWAIT) { 195 wakeup(msgbufp); 196 logsoftc.sc_state &= ~LOG_RDWAIT; 197 } 198 callout_reset(&logsoftc.sc_callout, hz / log_wakeups_per_second, 199 logtimeout, NULL); 200 } 201 202 /*ARGSUSED*/ 203 static int 204 logioctl(struct cdev *dev, u_long com, caddr_t data, int flag, struct thread *td) 205 { 206 207 switch (com) { 208 209 /* return number of characters immediately available */ 210 case FIONREAD: 211 *(int *)data = msgbuf_getcount(msgbufp); 212 break; 213 214 case FIONBIO: 215 break; 216 217 case FIOASYNC: 218 if (*(int *)data) 219 logsoftc.sc_state |= LOG_ASYNC; 220 else 221 logsoftc.sc_state &= ~LOG_ASYNC; 222 break; 223 224 case FIOSETOWN: 225 return (fsetown(*(int *)data, &logsoftc.sc_sigio)); 226 227 case FIOGETOWN: 228 *(int *)data = fgetown(&logsoftc.sc_sigio); 229 break; 230 231 /* This is deprecated, FIOSETOWN should be used instead. */ 232 case TIOCSPGRP: 233 return (fsetown(-(*(int *)data), &logsoftc.sc_sigio)); 234 235 /* This is deprecated, FIOGETOWN should be used instead */ 236 case TIOCGPGRP: 237 *(int *)data = -fgetown(&logsoftc.sc_sigio); 238 break; 239 240 default: 241 return (ENOTTY); 242 } 243 return (0); 244 } 245 246 static void 247 log_drvinit(void *unused) 248 { 249 250 make_dev(&log_cdevsw, 0, UID_ROOT, GID_WHEEL, 0600, "klog"); 251 } 252 253 SYSINIT(logdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE,log_drvinit,NULL) 254