1 /* $OpenBSD: subr_log.c,v 1.11 2003/09/23 16:51:12 millert Exp $ */ 2 /* $NetBSD: subr_log.c,v 1.11 1996/03/30 22:24:44 christos Exp $ */ 3 4 /* 5 * Copyright (c) 1982, 1986, 1993 6 * The Regents of the University of California. All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 * 32 * @(#)subr_log.c 8.1 (Berkeley) 6/10/93 33 */ 34 35 /* 36 * Error log buffer for kernel printf's. 37 */ 38 39 #include <sys/param.h> 40 #include <sys/systm.h> 41 #include <sys/proc.h> 42 #include <sys/vnode.h> 43 #include <sys/ioctl.h> 44 #include <sys/msgbuf.h> 45 #include <sys/file.h> 46 #include <sys/signalvar.h> 47 #include <sys/syslog.h> 48 #include <sys/conf.h> 49 #include <sys/poll.h> 50 51 #define LOG_RDPRI (PZERO + 1) 52 53 #define LOG_ASYNC 0x04 54 #define LOG_RDWAIT 0x08 55 56 struct logsoftc { 57 int sc_state; /* see above for possibilities */ 58 struct selinfo sc_selp; /* process waiting on select call */ 59 int sc_pgid; /* process/group for async I/O */ 60 uid_t sc_siguid; /* uid for process that set sc_pgid */ 61 uid_t sc_sigeuid; /* euid for process that set sc_pgid */ 62 } logsoftc; 63 64 int log_open; /* also used in log() */ 65 int msgbufmapped; /* is the message buffer mapped */ 66 int msgbufenabled; /* is logging to the buffer enabled */ 67 struct msgbuf *msgbufp; /* the mapped buffer, itself. */ 68 69 void filt_logrdetach(struct knote *kn); 70 int filt_logread(struct knote *kn, long hint); 71 72 struct filterops logread_filtops = 73 { 1, NULL, filt_logrdetach, filt_logread}; 74 75 void 76 initmsgbuf(buf, bufsize) 77 caddr_t buf; 78 size_t bufsize; 79 { 80 register struct msgbuf *mbp; 81 long new_bufs; 82 83 /* Sanity-check the given size. */ 84 if (bufsize < sizeof(struct msgbuf)) 85 return; 86 87 mbp = msgbufp = (struct msgbuf *)buf; 88 89 new_bufs = bufsize - offsetof(struct msgbuf, msg_bufc); 90 if ((mbp->msg_magic != MSG_MAGIC) || (mbp->msg_bufs != new_bufs) || 91 (mbp->msg_bufr < 0) || (mbp->msg_bufr >= mbp->msg_bufs) || 92 (mbp->msg_bufx < 0) || (mbp->msg_bufx >= mbp->msg_bufs)) { 93 /* 94 * If the buffer magic number is wrong, has changed 95 * size (which shouldn't happen often), or is 96 * internally inconsistent, initialize it. 97 */ 98 99 bzero(buf, bufsize); 100 mbp->msg_magic = MSG_MAGIC; 101 mbp->msg_bufs = new_bufs; 102 } 103 104 /* mark it as ready for use. */ 105 msgbufmapped = msgbufenabled = 1; 106 } 107 108 /*ARGSUSED*/ 109 int 110 logopen(dev, flags, mode, p) 111 dev_t dev; 112 int flags, mode; 113 struct proc *p; 114 { 115 if (log_open) 116 return (EBUSY); 117 log_open = 1; 118 return (0); 119 } 120 121 /*ARGSUSED*/ 122 int 123 logclose(dev, flag, mode, p) 124 dev_t dev; 125 int flag, mode; 126 struct proc *p; 127 { 128 129 log_open = 0; 130 logsoftc.sc_state = 0; 131 return (0); 132 } 133 134 /*ARGSUSED*/ 135 int 136 logread(dev, uio, flag) 137 dev_t dev; 138 struct uio *uio; 139 int flag; 140 { 141 register struct msgbuf *mbp = msgbufp; 142 register long l; 143 register int s; 144 int error = 0; 145 146 s = splhigh(); 147 while (mbp->msg_bufr == mbp->msg_bufx) { 148 if (flag & IO_NDELAY) { 149 splx(s); 150 return (EWOULDBLOCK); 151 } 152 logsoftc.sc_state |= LOG_RDWAIT; 153 error = tsleep(mbp, LOG_RDPRI | PCATCH, 154 "klog", 0); 155 if (error) { 156 splx(s); 157 return (error); 158 } 159 } 160 splx(s); 161 logsoftc.sc_state &= ~LOG_RDWAIT; 162 163 while (uio->uio_resid > 0) { 164 l = mbp->msg_bufx - mbp->msg_bufr; 165 if (l < 0) 166 l = mbp->msg_bufs - mbp->msg_bufr; 167 l = min(l, uio->uio_resid); 168 if (l == 0) 169 break; 170 error = uiomove(&mbp->msg_bufc[mbp->msg_bufr], (int)l, uio); 171 if (error) 172 break; 173 mbp->msg_bufr += l; 174 if (mbp->msg_bufr < 0 || mbp->msg_bufr >= mbp->msg_bufs) 175 mbp->msg_bufr = 0; 176 } 177 return (error); 178 } 179 180 /*ARGSUSED*/ 181 int 182 logpoll(dev, events, p) 183 dev_t dev; 184 int events; 185 struct proc *p; 186 { 187 int revents = 0; 188 int s = splhigh(); 189 190 if (events & (POLLIN | POLLRDNORM)) { 191 if (msgbufp->msg_bufr != msgbufp->msg_bufx) 192 revents |= events & (POLLIN | POLLRDNORM); 193 else 194 selrecord(p, &logsoftc.sc_selp); 195 } 196 splx(s); 197 return (revents); 198 } 199 200 int 201 logkqfilter(dev_t dev, struct knote *kn) 202 { 203 struct klist *klist; 204 int s; 205 206 switch (kn->kn_filter) { 207 case EVFILT_READ: 208 klist = &logsoftc.sc_selp.si_note; 209 kn->kn_fop = &logread_filtops; 210 break; 211 default: 212 return (1); 213 } 214 215 kn->kn_hook = (void *)msgbufp; 216 217 s = splhigh(); 218 SLIST_INSERT_HEAD(klist, kn, kn_selnext); 219 splx(s); 220 221 return (0); 222 } 223 224 void 225 filt_logrdetach(struct knote *kn) 226 { 227 int s = splhigh(); 228 229 SLIST_REMOVE(&logsoftc.sc_selp.si_note, kn, knote, kn_selnext); 230 splx(s); 231 } 232 233 int 234 filt_logread(struct knote *kn, long hint) 235 { 236 struct msgbuf *p = (struct msgbuf *)kn->kn_hook; 237 238 kn->kn_data = (int)(p->msg_bufx - p->msg_bufr); 239 240 return (p->msg_bufx != p->msg_bufr); 241 } 242 243 void 244 logwakeup() 245 { 246 if (!log_open) 247 return; 248 selwakeup(&logsoftc.sc_selp); 249 if (logsoftc.sc_state & LOG_ASYNC) 250 csignal(logsoftc.sc_pgid, SIGIO, 251 logsoftc.sc_siguid, logsoftc.sc_sigeuid); 252 if (logsoftc.sc_state & LOG_RDWAIT) { 253 wakeup(msgbufp); 254 logsoftc.sc_state &= ~LOG_RDWAIT; 255 } 256 KNOTE(&logsoftc.sc_selp.si_note, 0); 257 } 258 259 /*ARGSUSED*/ 260 int 261 logioctl(dev, com, data, flag, p) 262 dev_t dev; 263 u_long com; 264 caddr_t data; 265 int flag; 266 struct proc *p; 267 { 268 long l; 269 int s; 270 271 switch (com) { 272 273 /* return number of characters immediately available */ 274 case FIONREAD: 275 s = splhigh(); 276 l = msgbufp->msg_bufx - msgbufp->msg_bufr; 277 splx(s); 278 if (l < 0) 279 l += msgbufp->msg_bufs; 280 *(int *)data = l; 281 break; 282 283 case FIONBIO: 284 break; 285 286 case FIOASYNC: 287 if (*(int *)data) 288 logsoftc.sc_state |= LOG_ASYNC; 289 else 290 logsoftc.sc_state &= ~LOG_ASYNC; 291 break; 292 293 case TIOCSPGRP: 294 logsoftc.sc_pgid = *(int *)data; 295 logsoftc.sc_siguid = p->p_cred->p_ruid; 296 logsoftc.sc_sigeuid = p->p_ucred->cr_uid; 297 break; 298 299 case TIOCGPGRP: 300 *(int *)data = logsoftc.sc_pgid; 301 break; 302 303 default: 304 return (-1); 305 } 306 return (0); 307 } 308