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: src/sys/kern/subr_log.c,v 1.39.2.2 2001/06/02 08:11:25 phk Exp $ 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/device.h> 45 #include <sys/proc.h> 46 #include <sys/vnode.h> 47 #include <sys/filio.h> 48 #include <sys/ttycom.h> 49 #include <sys/msgbuf.h> 50 #include <sys/signalvar.h> 51 #include <sys/kernel.h> 52 #include <sys/event.h> 53 #include <sys/filedesc.h> 54 #include <sys/sysctl.h> 55 #include <sys/thread2.h> 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_kqfilter_t logkqfilter; 65 66 static void logtimeout(void *arg); 67 static void logfiltdetach(struct knote *kn); 68 static int logfiltread(struct knote *kn, long hint); 69 70 #define CDEV_MAJOR 7 71 static struct dev_ops log_ops = { 72 { "log", 0, 0 }, 73 .d_open = logopen, 74 .d_close = logclose, 75 .d_read = logread, 76 .d_ioctl = logioctl, 77 .d_kqfilter = logkqfilter 78 }; 79 80 static struct logsoftc { 81 int sc_state; /* see above for possibilities */ 82 struct kqinfo sc_kqp; /* processes waiting on I/O */ 83 struct sigio *sc_sigio; /* information for async I/O */ 84 struct callout sc_callout; /* callout to wakeup syslog */ 85 } logsoftc; 86 87 int log_open; /* also used in log() */ 88 89 /* Times per second to check for a pending syslog wakeup. */ 90 static int log_wakeups_per_second = 5; 91 SYSCTL_INT(_kern, OID_AUTO, log_wakeups_per_second, CTLFLAG_RW, 92 &log_wakeups_per_second, 0, ""); 93 94 /*ARGSUSED*/ 95 static int 96 logopen(struct dev_open_args *ap) 97 { 98 struct proc *p = curproc; 99 100 KKASSERT(p != NULL); 101 if (log_open) 102 return (EBUSY); 103 log_open = 1; 104 callout_init_mp(&logsoftc.sc_callout); 105 fsetown(p->p_pid, &logsoftc.sc_sigio); /* signal process only */ 106 callout_reset(&logsoftc.sc_callout, hz / log_wakeups_per_second, 107 logtimeout, NULL); 108 return (0); 109 } 110 111 /*ARGSUSED*/ 112 static int 113 logclose(struct dev_close_args *ap) 114 { 115 log_open = 0; 116 callout_stop(&logsoftc.sc_callout); 117 logsoftc.sc_state = 0; 118 funsetown(&logsoftc.sc_sigio); 119 return (0); 120 } 121 122 /*ARGSUSED*/ 123 static int 124 logread(struct dev_read_args *ap) 125 { 126 struct uio *uio = ap->a_uio; 127 struct msgbuf *mbp = msgbufp; 128 long l; 129 int error = 0; 130 131 crit_enter(); 132 while (mbp->msg_bufr == mbp->msg_bufx) { 133 if (ap->a_ioflag & IO_NDELAY) { 134 crit_exit(); 135 return (EWOULDBLOCK); 136 } 137 logsoftc.sc_state |= LOG_RDWAIT; 138 if ((error = tsleep((caddr_t)mbp, PCATCH, "klog", 0))) { 139 crit_exit(); 140 return (error); 141 } 142 } 143 crit_exit(); 144 logsoftc.sc_state &= ~LOG_RDWAIT; 145 146 while (uio->uio_resid > 0) { 147 l = (long)mbp->msg_bufx - (long)mbp->msg_bufr; 148 if (l < 0) 149 l = mbp->msg_size - mbp->msg_bufr; 150 l = (long)szmin(l, uio->uio_resid); 151 if (l == 0) 152 break; 153 error = uiomove((caddr_t)msgbufp->msg_ptr + mbp->msg_bufr, 154 (size_t)l, uio); 155 if (error) 156 break; 157 mbp->msg_bufr += l; 158 if (mbp->msg_bufr >= mbp->msg_size) 159 mbp->msg_bufr = 0; 160 } 161 return (error); 162 } 163 164 static struct filterops logread_filtops = 165 { FILTEROP_ISFD, NULL, logfiltdetach, logfiltread }; 166 167 static int 168 logkqfilter(struct dev_kqfilter_args *ap) 169 { 170 struct knote *kn = ap->a_kn; 171 struct klist *klist = &logsoftc.sc_kqp.ki_note; 172 173 ap->a_result = 0; 174 switch (kn->kn_filter) { 175 case EVFILT_READ: 176 kn->kn_fop = &logread_filtops; 177 break; 178 default: 179 ap->a_result = EOPNOTSUPP; 180 return (0); 181 } 182 183 knote_insert(klist, kn); 184 185 return (0); 186 } 187 188 static void 189 logfiltdetach(struct knote *kn) 190 { 191 struct klist *klist = &logsoftc.sc_kqp.ki_note; 192 193 knote_remove(klist, kn); 194 } 195 196 static int 197 logfiltread(struct knote *kn, long hint) 198 { 199 int ret = 0; 200 201 crit_enter(); 202 if (msgbufp->msg_bufr != msgbufp->msg_bufx) 203 ret = 1; 204 crit_exit(); 205 206 return (ret); 207 } 208 209 static void 210 logtimeout(void *arg) 211 { 212 if (!log_open) 213 return; 214 if (msgbuftrigger == 0) { 215 callout_reset(&logsoftc.sc_callout, 216 hz / log_wakeups_per_second, logtimeout, NULL); 217 return; 218 } 219 msgbuftrigger = 0; 220 KNOTE(&logsoftc.sc_kqp.ki_note, 0); 221 if ((logsoftc.sc_state & LOG_ASYNC) && logsoftc.sc_sigio != NULL) 222 pgsigio(logsoftc.sc_sigio, SIGIO, 0); 223 if (logsoftc.sc_state & LOG_RDWAIT) { 224 wakeup((caddr_t)msgbufp); 225 logsoftc.sc_state &= ~LOG_RDWAIT; 226 } 227 callout_reset(&logsoftc.sc_callout, hz / log_wakeups_per_second, 228 logtimeout, NULL); 229 } 230 231 /*ARGSUSED*/ 232 static int 233 logioctl(struct dev_ioctl_args *ap) 234 { 235 long l; 236 237 switch (ap->a_cmd) { 238 case FIONREAD: 239 /* return number of characters immediately available */ 240 crit_enter(); 241 l = msgbufp->msg_bufx - msgbufp->msg_bufr; 242 crit_exit(); 243 if (l < 0) 244 l += msgbufp->msg_size; 245 *(int *)ap->a_data = l; 246 break; 247 248 case FIOASYNC: 249 if (*(int *)ap->a_data) 250 logsoftc.sc_state |= LOG_ASYNC; 251 else 252 logsoftc.sc_state &= ~LOG_ASYNC; 253 break; 254 255 case FIOSETOWN: 256 return (fsetown(*(int *)ap->a_data, &logsoftc.sc_sigio)); 257 258 case FIOGETOWN: 259 *(int *)ap->a_data = fgetown(&logsoftc.sc_sigio); 260 break; 261 262 /* This is deprecated, FIOSETOWN should be used instead. */ 263 case TIOCSPGRP: 264 return (fsetown(-(*(int *)ap->a_data), &logsoftc.sc_sigio)); 265 266 /* This is deprecated, FIOGETOWN should be used instead */ 267 case TIOCGPGRP: 268 *(int *)ap->a_data = -fgetown(&logsoftc.sc_sigio); 269 break; 270 271 default: 272 return (ENOTTY); 273 } 274 return (0); 275 } 276 277 static void 278 log_drvinit(void *unused) 279 { 280 make_dev(&log_ops, 0, UID_ROOT, GID_WHEEL, 0600, "klog"); 281 } 282 283 SYSINIT(logdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,log_drvinit,NULL) 284