1 /* $OpenBSD: subr_log.c,v 1.10 2003/07/21 22:44:50 tedu 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 50 #define LOG_RDPRI (PZERO + 1) 51 52 #define LOG_ASYNC 0x04 53 #define LOG_RDWAIT 0x08 54 55 struct logsoftc { 56 int sc_state; /* see above for possibilities */ 57 struct selinfo sc_selp; /* process waiting on select call */ 58 int sc_pgid; /* process/group for async I/O */ 59 uid_t sc_siguid; /* uid for process that set sc_pgid */ 60 uid_t sc_sigeuid; /* euid for process that set sc_pgid */ 61 } logsoftc; 62 63 int log_open; /* also used in log() */ 64 int msgbufmapped; /* is the message buffer mapped */ 65 int msgbufenabled; /* is logging to the buffer enabled */ 66 struct msgbuf *msgbufp; /* the mapped buffer, itself. */ 67 68 void filt_logrdetach(struct knote *kn); 69 int filt_logread(struct knote *kn, long hint); 70 71 struct filterops logread_filtops = 72 { 1, NULL, filt_logrdetach, filt_logread}; 73 74 void 75 initmsgbuf(buf, bufsize) 76 caddr_t buf; 77 size_t bufsize; 78 { 79 register struct msgbuf *mbp; 80 long new_bufs; 81 82 /* Sanity-check the given size. */ 83 if (bufsize < sizeof(struct msgbuf)) 84 return; 85 86 mbp = msgbufp = (struct msgbuf *)buf; 87 88 new_bufs = bufsize - offsetof(struct 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 bzero(buf, 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 if (log_open) 115 return (EBUSY); 116 log_open = 1; 117 return (0); 118 } 119 120 /*ARGSUSED*/ 121 int 122 logclose(dev, flag, mode, p) 123 dev_t dev; 124 int flag, mode; 125 struct proc *p; 126 { 127 128 log_open = 0; 129 logsoftc.sc_state = 0; 130 return (0); 131 } 132 133 /*ARGSUSED*/ 134 int 135 logread(dev, uio, flag) 136 dev_t dev; 137 struct uio *uio; 138 int flag; 139 { 140 register struct msgbuf *mbp = msgbufp; 141 register long l; 142 register int s; 143 int error = 0; 144 145 s = splhigh(); 146 while (mbp->msg_bufr == mbp->msg_bufx) { 147 if (flag & IO_NDELAY) { 148 splx(s); 149 return (EWOULDBLOCK); 150 } 151 logsoftc.sc_state |= LOG_RDWAIT; 152 error = tsleep(mbp, LOG_RDPRI | PCATCH, 153 "klog", 0); 154 if (error) { 155 splx(s); 156 return (error); 157 } 158 } 159 splx(s); 160 logsoftc.sc_state &= ~LOG_RDWAIT; 161 162 while (uio->uio_resid > 0) { 163 l = mbp->msg_bufx - mbp->msg_bufr; 164 if (l < 0) 165 l = mbp->msg_bufs - mbp->msg_bufr; 166 l = min(l, uio->uio_resid); 167 if (l == 0) 168 break; 169 error = uiomove(&mbp->msg_bufc[mbp->msg_bufr], (int)l, uio); 170 if (error) 171 break; 172 mbp->msg_bufr += l; 173 if (mbp->msg_bufr < 0 || mbp->msg_bufr >= mbp->msg_bufs) 174 mbp->msg_bufr = 0; 175 } 176 return (error); 177 } 178 179 /*ARGSUSED*/ 180 int 181 logselect(dev, rw, p) 182 dev_t dev; 183 int rw; 184 struct proc *p; 185 { 186 int s = splhigh(); 187 188 switch (rw) { 189 190 case FREAD: 191 if (msgbufp->msg_bufr != msgbufp->msg_bufx) { 192 splx(s); 193 return (1); 194 } 195 selrecord(p, &logsoftc.sc_selp); 196 break; 197 } 198 splx(s); 199 return (0); 200 } 201 202 int 203 logkqfilter(dev_t dev, struct knote *kn) 204 { 205 struct klist *klist; 206 int s; 207 208 switch (kn->kn_filter) { 209 case EVFILT_READ: 210 klist = &logsoftc.sc_selp.si_note; 211 kn->kn_fop = &logread_filtops; 212 break; 213 default: 214 return (1); 215 } 216 217 kn->kn_hook = (void *)msgbufp; 218 219 s = splhigh(); 220 SLIST_INSERT_HEAD(klist, kn, kn_selnext); 221 splx(s); 222 223 return (0); 224 } 225 226 void 227 filt_logrdetach(struct knote *kn) 228 { 229 int s = splhigh(); 230 231 SLIST_REMOVE(&logsoftc.sc_selp.si_note, kn, knote, kn_selnext); 232 splx(s); 233 } 234 235 int 236 filt_logread(struct knote *kn, long hint) 237 { 238 struct msgbuf *p = (struct msgbuf *)kn->kn_hook; 239 240 kn->kn_data = (int)(p->msg_bufx - p->msg_bufr); 241 242 return (p->msg_bufx != p->msg_bufr); 243 } 244 245 void 246 logwakeup() 247 { 248 if (!log_open) 249 return; 250 selwakeup(&logsoftc.sc_selp); 251 if (logsoftc.sc_state & LOG_ASYNC) 252 csignal(logsoftc.sc_pgid, SIGIO, 253 logsoftc.sc_siguid, logsoftc.sc_sigeuid); 254 if (logsoftc.sc_state & LOG_RDWAIT) { 255 wakeup(msgbufp); 256 logsoftc.sc_state &= ~LOG_RDWAIT; 257 } 258 KNOTE(&logsoftc.sc_selp.si_note, 0); 259 } 260 261 /*ARGSUSED*/ 262 int 263 logioctl(dev, com, data, flag, p) 264 dev_t dev; 265 u_long com; 266 caddr_t data; 267 int flag; 268 struct proc *p; 269 { 270 long l; 271 int s; 272 273 switch (com) { 274 275 /* return number of characters immediately available */ 276 case FIONREAD: 277 s = splhigh(); 278 l = msgbufp->msg_bufx - msgbufp->msg_bufr; 279 splx(s); 280 if (l < 0) 281 l += msgbufp->msg_bufs; 282 *(int *)data = l; 283 break; 284 285 case FIONBIO: 286 break; 287 288 case FIOASYNC: 289 if (*(int *)data) 290 logsoftc.sc_state |= LOG_ASYNC; 291 else 292 logsoftc.sc_state &= ~LOG_ASYNC; 293 break; 294 295 case TIOCSPGRP: 296 logsoftc.sc_pgid = *(int *)data; 297 logsoftc.sc_siguid = p->p_cred->p_ruid; 298 logsoftc.sc_sigeuid = p->p_ucred->cr_uid; 299 break; 300 301 case TIOCGPGRP: 302 *(int *)data = logsoftc.sc_pgid; 303 break; 304 305 default: 306 return (-1); 307 } 308 return (0); 309 } 310