subr_log.c revision 1.21
1 /* $NetBSD: subr_log.c,v 1.21 2001/11/12 15:25:19 lukem Exp $ */ 2 3 /* 4 * Copyright (c) 1982, 1986, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by the University of 18 * California, Berkeley and its contributors. 19 * 4. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 * 35 * @(#)subr_log.c 8.3 (Berkeley) 2/14/95 36 */ 37 38 /* 39 * Error log buffer for kernel printf's. 40 */ 41 42 #include <sys/cdefs.h> 43 __KERNEL_RCSID(0, "$NetBSD: subr_log.c,v 1.21 2001/11/12 15:25:19 lukem Exp $"); 44 45 #include <sys/param.h> 46 #include <sys/systm.h> 47 #include <sys/proc.h> 48 #include <sys/vnode.h> 49 #include <sys/ioctl.h> 50 #include <sys/msgbuf.h> 51 #include <sys/file.h> 52 #include <sys/signalvar.h> 53 #include <sys/syslog.h> 54 #include <sys/conf.h> 55 #include <sys/select.h> 56 #include <sys/poll.h> 57 58 #define LOG_RDPRI (PZERO + 1) 59 60 #define LOG_ASYNC 0x04 61 #define LOG_RDWAIT 0x08 62 63 struct logsoftc { 64 int sc_state; /* see above for possibilities */ 65 struct selinfo sc_selp; /* process waiting on select call */ 66 int sc_pgid; /* process/group for async I/O */ 67 } logsoftc; 68 69 int log_open; /* also used in log() */ 70 int msgbufmapped; /* is the message buffer mapped */ 71 int msgbufenabled; /* is logging to the buffer enabled */ 72 struct kern_msgbuf *msgbufp; /* the mapped buffer, itself. */ 73 74 void 75 initmsgbuf(buf, bufsize) 76 caddr_t buf; 77 size_t bufsize; 78 { 79 struct kern_msgbuf *mbp; 80 long new_bufs; 81 82 /* Sanity-check the given size. */ 83 if (bufsize < sizeof(struct kern_msgbuf)) 84 return; 85 86 mbp = msgbufp = (struct kern_msgbuf *)buf; 87 88 new_bufs = bufsize - offsetof(struct kern_msgbuf, msg_bufc); 89 if ((mbp->msg_magic != MSG_MAGIC) || (mbp->msg_bufs != new_bufs) || 90 (mbp->msg_bufr < 0) || (mbp->msg_bufr >= mbp->msg_bufs) || 91 (mbp->msg_bufx < 0) || (mbp->msg_bufx >= mbp->msg_bufs)) { 92 /* 93 * If the buffer magic number is wrong, has changed 94 * size (which shouldn't happen often), or is 95 * internally inconsistent, initialize it. 96 */ 97 98 memset(buf, 0, bufsize); 99 mbp->msg_magic = MSG_MAGIC; 100 mbp->msg_bufs = new_bufs; 101 } 102 103 /* mark it as ready for use. */ 104 msgbufmapped = msgbufenabled = 1; 105 } 106 107 /*ARGSUSED*/ 108 int 109 logopen(dev, flags, mode, p) 110 dev_t dev; 111 int flags, mode; 112 struct proc *p; 113 { 114 struct kern_msgbuf *mbp = msgbufp; 115 116 if (log_open) 117 return (EBUSY); 118 log_open = 1; 119 logsoftc.sc_pgid = p->p_pid; /* signal process only */ 120 /* 121 * The message buffer is initialized during system configuration. 122 * If it's been clobbered, note that and return an error. (This 123 * allows a user to potentially read the buffer via /dev/kmem, 124 * and try to figure out what clobbered it. 125 */ 126 if (mbp->msg_magic != MSG_MAGIC) { 127 msgbufenabled = 0; 128 return (ENXIO); 129 } 130 131 return (0); 132 } 133 134 /*ARGSUSED*/ 135 int 136 logclose(dev, flag, mode, p) 137 dev_t dev; 138 int flag, mode; 139 struct proc *p; 140 { 141 142 log_open = 0; 143 logsoftc.sc_state = 0; 144 return (0); 145 } 146 147 /*ARGSUSED*/ 148 int 149 logread(dev, uio, flag) 150 dev_t dev; 151 struct uio *uio; 152 int flag; 153 { 154 struct kern_msgbuf *mbp = msgbufp; 155 long l; 156 int s; 157 int error = 0; 158 159 s = splhigh(); 160 while (mbp->msg_bufr == mbp->msg_bufx) { 161 if (flag & IO_NDELAY) { 162 splx(s); 163 return (EWOULDBLOCK); 164 } 165 logsoftc.sc_state |= LOG_RDWAIT; 166 error = tsleep((caddr_t)mbp, LOG_RDPRI | PCATCH, 167 "klog", 0); 168 if (error) { 169 splx(s); 170 return (error); 171 } 172 } 173 splx(s); 174 logsoftc.sc_state &= ~LOG_RDWAIT; 175 176 while (uio->uio_resid > 0) { 177 l = mbp->msg_bufx - mbp->msg_bufr; 178 if (l < 0) 179 l = mbp->msg_bufs - mbp->msg_bufr; 180 l = min(l, uio->uio_resid); 181 if (l == 0) 182 break; 183 error = uiomove((caddr_t)&mbp->msg_bufc[mbp->msg_bufr], 184 (int)l, uio); 185 if (error) 186 break; 187 mbp->msg_bufr += l; 188 if (mbp->msg_bufr < 0 || mbp->msg_bufr >= mbp->msg_bufs) 189 mbp->msg_bufr = 0; 190 } 191 return (error); 192 } 193 194 /*ARGSUSED*/ 195 int 196 logpoll(dev, events, p) 197 dev_t dev; 198 int events; 199 struct proc *p; 200 { 201 int revents = 0; 202 int s = splhigh(); 203 204 if (events & (POLLIN | POLLRDNORM)) { 205 if (msgbufp->msg_bufr != msgbufp->msg_bufx) 206 revents |= events & (POLLIN | POLLRDNORM); 207 else 208 selrecord(p, &logsoftc.sc_selp); 209 } 210 211 splx(s); 212 return (revents); 213 } 214 215 void 216 logwakeup() 217 { 218 struct proc *p; 219 220 if (!log_open) 221 return; 222 selwakeup(&logsoftc.sc_selp); 223 if (logsoftc.sc_state & LOG_ASYNC) { 224 if (logsoftc.sc_pgid < 0) 225 gsignal(-logsoftc.sc_pgid, SIGIO); 226 else if (logsoftc.sc_pgid > 0 && 227 (p = pfind(logsoftc.sc_pgid)) != NULL) 228 psignal(p, SIGIO); 229 } 230 if (logsoftc.sc_state & LOG_RDWAIT) { 231 wakeup((caddr_t)msgbufp); 232 logsoftc.sc_state &= ~LOG_RDWAIT; 233 } 234 } 235 236 /*ARGSUSED*/ 237 int 238 logioctl(dev, com, data, flag, p) 239 dev_t dev; 240 u_long com; 241 caddr_t data; 242 int flag; 243 struct proc *p; 244 { 245 long l; 246 int s; 247 248 switch (com) { 249 250 /* return number of characters immediately available */ 251 case FIONREAD: 252 s = splhigh(); 253 l = msgbufp->msg_bufx - msgbufp->msg_bufr; 254 splx(s); 255 if (l < 0) 256 l += msgbufp->msg_bufs; 257 *(int *)data = l; 258 break; 259 260 case FIONBIO: 261 break; 262 263 case FIOASYNC: 264 if (*(int *)data) 265 logsoftc.sc_state |= LOG_ASYNC; 266 else 267 logsoftc.sc_state &= ~LOG_ASYNC; 268 break; 269 270 case TIOCSPGRP: 271 logsoftc.sc_pgid = *(int *)data; 272 break; 273 274 case TIOCGPGRP: 275 *(int *)data = logsoftc.sc_pgid; 276 break; 277 278 default: 279 return (-1); 280 } 281 return (0); 282 } 283
Indexes created Tue Sep 23 02:09:52 GMT 2025