1 /* $OpenBSD: subr_log.c,v 1.8 2002/06/29 02:58:14 mickey 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. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * @(#)subr_log.c 8.1 (Berkeley) 6/10/93 37 */ 38 39 /* 40 * Error log buffer for kernel printf's. 41 */ 42 43 #include <sys/param.h> 44 #include <sys/systm.h> 45 #include <sys/proc.h> 46 #include <sys/vnode.h> 47 #include <sys/ioctl.h> 48 #include <sys/msgbuf.h> 49 #include <sys/file.h> 50 #include <sys/signalvar.h> 51 #include <sys/syslog.h> 52 #include <sys/conf.h> 53 54 #define LOG_RDPRI (PZERO + 1) 55 56 #define LOG_ASYNC 0x04 57 #define LOG_RDWAIT 0x08 58 59 struct logsoftc { 60 int sc_state; /* see above for possibilities */ 61 struct selinfo sc_selp; /* process waiting on select call */ 62 int sc_pgid; /* process/group for async I/O */ 63 uid_t sc_siguid; /* uid for process that set sc_pgid */ 64 uid_t sc_sigeuid; /* euid for process that set sc_pgid */ 65 } logsoftc; 66 67 int log_open; /* also used in log() */ 68 int msgbufmapped; /* is the message buffer mapped */ 69 int msgbufenabled; /* is logging to the buffer enabled */ 70 struct msgbuf *msgbufp; /* the mapped buffer, itself. */ 71 72 void filt_logrdetach(struct knote *kn); 73 int filt_logread(struct knote *kn, long hint); 74 75 struct filterops logread_filtops = 76 { 1, NULL, filt_logrdetach, filt_logread}; 77 78 void 79 initmsgbuf(buf, bufsize) 80 caddr_t buf; 81 size_t bufsize; 82 { 83 register struct msgbuf *mbp; 84 long new_bufs; 85 86 /* Sanity-check the given size. */ 87 if (bufsize < sizeof(struct msgbuf)) 88 return; 89 90 mbp = msgbufp = (struct msgbuf *)buf; 91 92 new_bufs = bufsize - offsetof(struct msgbuf, msg_bufc); 93 if ((mbp->msg_magic != MSG_MAGIC) || (mbp->msg_bufs != new_bufs) || 94 (mbp->msg_bufr < 0) || (mbp->msg_bufr >= mbp->msg_bufs) || 95 (mbp->msg_bufx < 0) || (mbp->msg_bufx >= mbp->msg_bufs)) { 96 /* 97 * If the buffer magic number is wrong, has changed 98 * size (which shouldn't happen often), or is 99 * internally inconsistent, initialize it. 100 */ 101 102 bzero(buf, bufsize); 103 mbp->msg_magic = MSG_MAGIC; 104 mbp->msg_bufs = new_bufs; 105 } 106 107 /* mark it as ready for use. */ 108 msgbufmapped = msgbufenabled = 1; 109 } 110 111 /*ARGSUSED*/ 112 int 113 logopen(dev, flags, mode, p) 114 dev_t dev; 115 int flags, mode; 116 struct proc *p; 117 { 118 if (log_open) 119 return (EBUSY); 120 log_open = 1; 121 return (0); 122 } 123 124 /*ARGSUSED*/ 125 int 126 logclose(dev, flag, mode, p) 127 dev_t dev; 128 int flag, mode; 129 struct proc *p; 130 { 131 132 log_open = 0; 133 logsoftc.sc_state = 0; 134 return (0); 135 } 136 137 /*ARGSUSED*/ 138 int 139 logread(dev, uio, flag) 140 dev_t dev; 141 struct uio *uio; 142 int flag; 143 { 144 register struct msgbuf *mbp = msgbufp; 145 register long l; 146 register int s; 147 int error = 0; 148 149 s = splhigh(); 150 while (mbp->msg_bufr == mbp->msg_bufx) { 151 if (flag & IO_NDELAY) { 152 splx(s); 153 return (EWOULDBLOCK); 154 } 155 logsoftc.sc_state |= LOG_RDWAIT; 156 error = tsleep((caddr_t)mbp, LOG_RDPRI | PCATCH, 157 "klog", 0); 158 if (error) { 159 splx(s); 160 return (error); 161 } 162 } 163 splx(s); 164 logsoftc.sc_state &= ~LOG_RDWAIT; 165 166 while (uio->uio_resid > 0) { 167 l = mbp->msg_bufx - mbp->msg_bufr; 168 if (l < 0) 169 l = mbp->msg_bufs - mbp->msg_bufr; 170 l = min(l, uio->uio_resid); 171 if (l == 0) 172 break; 173 error = uiomove((caddr_t)&mbp->msg_bufc[mbp->msg_bufr], 174 (int)l, uio); 175 if (error) 176 break; 177 mbp->msg_bufr += l; 178 if (mbp->msg_bufr < 0 || mbp->msg_bufr >= mbp->msg_bufs) 179 mbp->msg_bufr = 0; 180 } 181 return (error); 182 } 183 184 /*ARGSUSED*/ 185 int 186 logselect(dev, rw, p) 187 dev_t dev; 188 int rw; 189 struct proc *p; 190 { 191 int s = splhigh(); 192 193 switch (rw) { 194 195 case FREAD: 196 if (msgbufp->msg_bufr != msgbufp->msg_bufx) { 197 splx(s); 198 return (1); 199 } 200 selrecord(p, &logsoftc.sc_selp); 201 break; 202 } 203 splx(s); 204 return (0); 205 } 206 207 int 208 logkqfilter(dev_t dev, struct knote *kn) 209 { 210 struct klist *klist; 211 int s; 212 213 switch (kn->kn_filter) { 214 case EVFILT_READ: 215 klist = &logsoftc.sc_selp.si_note; 216 kn->kn_fop = &logread_filtops; 217 break; 218 default: 219 return (1); 220 } 221 222 kn->kn_hook = (void *)msgbufp; 223 224 s = splhigh(); 225 SLIST_INSERT_HEAD(klist, kn, kn_selnext); 226 splx(s); 227 228 return (0); 229 } 230 231 void 232 filt_logrdetach(struct knote *kn) 233 { 234 int s = splhigh(); 235 236 SLIST_REMOVE(&logsoftc.sc_selp.si_note, kn, knote, kn_selnext); 237 splx(s); 238 } 239 240 int 241 filt_logread(struct knote *kn, long hint) 242 { 243 struct msgbuf *p = (struct msgbuf *)kn->kn_hook; 244 245 kn->kn_data = (int)(p->msg_bufx - p->msg_bufr); 246 247 return (p->msg_bufx != p->msg_bufr); 248 } 249 250 void 251 logwakeup() 252 { 253 if (!log_open) 254 return; 255 selwakeup(&logsoftc.sc_selp); 256 if (logsoftc.sc_state & LOG_ASYNC) 257 csignal(logsoftc.sc_pgid, SIGIO, 258 logsoftc.sc_siguid, logsoftc.sc_sigeuid); 259 if (logsoftc.sc_state & LOG_RDWAIT) { 260 wakeup((caddr_t)msgbufp); 261 logsoftc.sc_state &= ~LOG_RDWAIT; 262 } 263 KNOTE(&logsoftc.sc_selp.si_note, 0); 264 } 265 266 /*ARGSUSED*/ 267 int 268 logioctl(dev, com, data, flag, p) 269 dev_t dev; 270 u_long com; 271 caddr_t data; 272 int flag; 273 struct proc *p; 274 { 275 long l; 276 int s; 277 278 switch (com) { 279 280 /* return number of characters immediately available */ 281 case FIONREAD: 282 s = splhigh(); 283 l = msgbufp->msg_bufx - msgbufp->msg_bufr; 284 splx(s); 285 if (l < 0) 286 l += msgbufp->msg_bufs; 287 *(int *)data = l; 288 break; 289 290 case FIONBIO: 291 break; 292 293 case FIOASYNC: 294 if (*(int *)data) 295 logsoftc.sc_state |= LOG_ASYNC; 296 else 297 logsoftc.sc_state &= ~LOG_ASYNC; 298 break; 299 300 case TIOCSPGRP: 301 logsoftc.sc_pgid = *(int *)data; 302 logsoftc.sc_siguid = p->p_cred->p_ruid; 303 logsoftc.sc_sigeuid = p->p_ucred->cr_uid; 304 break; 305 306 case TIOCGPGRP: 307 *(int *)data = logsoftc.sc_pgid; 308 break; 309 310 default: 311 return (-1); 312 } 313 return (0); 314 } 315