1 /* $OpenBSD: subr_log.c,v 1.31 2015/09/02 13:21:37 bluhm 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/poll.h> 49 #include <sys/malloc.h> 50 #include <sys/filedesc.h> 51 #include <sys/socket.h> 52 #include <sys/socketvar.h> 53 54 #ifdef KTRACE 55 #include <sys/ktrace.h> 56 #endif 57 58 #include <sys/mount.h> 59 #include <sys/syscallargs.h> 60 61 #define LOG_RDPRI (PZERO + 1) 62 63 #define LOG_ASYNC 0x04 64 #define LOG_RDWAIT 0x08 65 66 struct logsoftc { 67 int sc_state; /* see above for possibilities */ 68 struct selinfo sc_selp; /* process waiting on select call */ 69 int sc_pgid; /* process/group for async I/O */ 70 uid_t sc_siguid; /* uid for process that set sc_pgid */ 71 uid_t sc_sigeuid; /* euid for process that set sc_pgid */ 72 } logsoftc; 73 74 int log_open; /* also used in log() */ 75 int msgbufmapped; /* is the message buffer mapped */ 76 struct msgbuf *msgbufp; /* the mapped buffer, itself. */ 77 struct msgbuf *consbufp; /* console message buffer. */ 78 struct file *syslogf; 79 80 void filt_logrdetach(struct knote *kn); 81 int filt_logread(struct knote *kn, long hint); 82 83 struct filterops logread_filtops = 84 { 1, NULL, filt_logrdetach, filt_logread}; 85 86 int dosendsyslog(struct proc *, const char *, size_t, enum uio_seg); 87 88 void 89 initmsgbuf(caddr_t buf, size_t bufsize) 90 { 91 struct msgbuf *mbp; 92 long new_bufs; 93 94 /* Sanity-check the given size. */ 95 if (bufsize < sizeof(struct msgbuf)) 96 return; 97 98 mbp = msgbufp = (struct msgbuf *)buf; 99 100 new_bufs = bufsize - offsetof(struct msgbuf, msg_bufc); 101 if ((mbp->msg_magic != MSG_MAGIC) || (mbp->msg_bufs != new_bufs) || 102 (mbp->msg_bufr < 0) || (mbp->msg_bufr >= mbp->msg_bufs) || 103 (mbp->msg_bufx < 0) || (mbp->msg_bufx >= mbp->msg_bufs)) { 104 /* 105 * If the buffer magic number is wrong, has changed 106 * size (which shouldn't happen often), or is 107 * internally inconsistent, initialize it. 108 */ 109 110 memset(buf, 0, bufsize); 111 mbp->msg_magic = MSG_MAGIC; 112 mbp->msg_bufs = new_bufs; 113 } 114 115 /* Always start new buffer data on a new line. */ 116 if (mbp->msg_bufx > 0 && mbp->msg_bufc[mbp->msg_bufx - 1] != '\n') 117 msgbuf_putchar(msgbufp, '\n'); 118 119 /* mark it as ready for use. */ 120 msgbufmapped = 1; 121 } 122 123 void 124 initconsbuf(void) 125 { 126 long new_bufs; 127 128 /* Set up a buffer to collect /dev/console output */ 129 consbufp = malloc(CONSBUFSIZE, M_TEMP, M_NOWAIT|M_ZERO); 130 if (consbufp) { 131 new_bufs = CONSBUFSIZE - offsetof(struct msgbuf, msg_bufc); 132 consbufp->msg_magic = MSG_MAGIC; 133 consbufp->msg_bufs = new_bufs; 134 } 135 } 136 137 void 138 msgbuf_putchar(struct msgbuf *mbp, const char c) 139 { 140 if (mbp->msg_magic != MSG_MAGIC) 141 /* Nothing we can do */ 142 return; 143 144 mbp->msg_bufc[mbp->msg_bufx++] = c; 145 mbp->msg_bufl = min(mbp->msg_bufl+1, mbp->msg_bufs); 146 if (mbp->msg_bufx < 0 || mbp->msg_bufx >= mbp->msg_bufs) 147 mbp->msg_bufx = 0; 148 /* If the buffer is full, keep the most recent data. */ 149 if (mbp->msg_bufr == mbp->msg_bufx) { 150 if (++mbp->msg_bufr >= mbp->msg_bufs) 151 mbp->msg_bufr = 0; 152 } 153 } 154 155 /*ARGSUSED*/ 156 int 157 logopen(dev_t dev, int flags, int mode, struct proc *p) 158 { 159 if (log_open) 160 return (EBUSY); 161 log_open = 1; 162 return (0); 163 } 164 165 /*ARGSUSED*/ 166 int 167 logclose(dev_t dev, int flag, int mode, struct proc *p) 168 { 169 170 if (syslogf) 171 FRELE(syslogf, p); 172 syslogf = NULL; 173 log_open = 0; 174 logsoftc.sc_state = 0; 175 return (0); 176 } 177 178 /*ARGSUSED*/ 179 int 180 logread(dev_t dev, struct uio *uio, int flag) 181 { 182 struct msgbuf *mbp = msgbufp; 183 long l; 184 int s; 185 int error = 0; 186 187 s = splhigh(); 188 while (mbp->msg_bufr == mbp->msg_bufx) { 189 if (flag & IO_NDELAY) { 190 splx(s); 191 return (EWOULDBLOCK); 192 } 193 logsoftc.sc_state |= LOG_RDWAIT; 194 error = tsleep(mbp, LOG_RDPRI | PCATCH, 195 "klog", 0); 196 if (error) { 197 splx(s); 198 return (error); 199 } 200 } 201 splx(s); 202 logsoftc.sc_state &= ~LOG_RDWAIT; 203 204 while (uio->uio_resid > 0) { 205 l = mbp->msg_bufx - mbp->msg_bufr; 206 if (l < 0) 207 l = mbp->msg_bufs - mbp->msg_bufr; 208 l = min(l, uio->uio_resid); 209 if (l == 0) 210 break; 211 error = uiomovei(&mbp->msg_bufc[mbp->msg_bufr], (int)l, uio); 212 if (error) 213 break; 214 mbp->msg_bufr += l; 215 if (mbp->msg_bufr < 0 || mbp->msg_bufr >= mbp->msg_bufs) 216 mbp->msg_bufr = 0; 217 } 218 return (error); 219 } 220 221 /*ARGSUSED*/ 222 int 223 logpoll(dev_t dev, int events, struct proc *p) 224 { 225 int revents = 0; 226 int s = splhigh(); 227 228 if (events & (POLLIN | POLLRDNORM)) { 229 if (msgbufp->msg_bufr != msgbufp->msg_bufx) 230 revents |= events & (POLLIN | POLLRDNORM); 231 else 232 selrecord(p, &logsoftc.sc_selp); 233 } 234 splx(s); 235 return (revents); 236 } 237 238 int 239 logkqfilter(dev_t dev, struct knote *kn) 240 { 241 struct klist *klist; 242 int s; 243 244 switch (kn->kn_filter) { 245 case EVFILT_READ: 246 klist = &logsoftc.sc_selp.si_note; 247 kn->kn_fop = &logread_filtops; 248 break; 249 default: 250 return (EINVAL); 251 } 252 253 kn->kn_hook = (void *)msgbufp; 254 255 s = splhigh(); 256 SLIST_INSERT_HEAD(klist, kn, kn_selnext); 257 splx(s); 258 259 return (0); 260 } 261 262 void 263 filt_logrdetach(struct knote *kn) 264 { 265 int s = splhigh(); 266 267 SLIST_REMOVE(&logsoftc.sc_selp.si_note, kn, knote, kn_selnext); 268 splx(s); 269 } 270 271 int 272 filt_logread(struct knote *kn, long hint) 273 { 274 struct msgbuf *p = (struct msgbuf *)kn->kn_hook; 275 276 kn->kn_data = (int)(p->msg_bufx - p->msg_bufr); 277 278 return (p->msg_bufx != p->msg_bufr); 279 } 280 281 void 282 logwakeup(void) 283 { 284 if (!log_open) 285 return; 286 selwakeup(&logsoftc.sc_selp); 287 if (logsoftc.sc_state & LOG_ASYNC) 288 csignal(logsoftc.sc_pgid, SIGIO, 289 logsoftc.sc_siguid, logsoftc.sc_sigeuid); 290 if (logsoftc.sc_state & LOG_RDWAIT) { 291 wakeup(msgbufp); 292 logsoftc.sc_state &= ~LOG_RDWAIT; 293 } 294 } 295 296 /*ARGSUSED*/ 297 int 298 logioctl(dev_t dev, u_long com, caddr_t data, int flag, struct proc *p) 299 { 300 struct file *fp; 301 long l; 302 int error, s; 303 304 switch (com) { 305 306 /* return number of characters immediately available */ 307 case FIONREAD: 308 s = splhigh(); 309 l = msgbufp->msg_bufx - msgbufp->msg_bufr; 310 splx(s); 311 if (l < 0) 312 l += msgbufp->msg_bufs; 313 *(int *)data = l; 314 break; 315 316 case FIONBIO: 317 break; 318 319 case FIOASYNC: 320 if (*(int *)data) 321 logsoftc.sc_state |= LOG_ASYNC; 322 else 323 logsoftc.sc_state &= ~LOG_ASYNC; 324 break; 325 326 case TIOCSPGRP: 327 logsoftc.sc_pgid = *(int *)data; 328 logsoftc.sc_siguid = p->p_ucred->cr_ruid; 329 logsoftc.sc_sigeuid = p->p_ucred->cr_uid; 330 break; 331 332 case TIOCGPGRP: 333 *(int *)data = logsoftc.sc_pgid; 334 break; 335 336 case LIOCSFD: 337 if ((error = suser(p, 0)) != 0) 338 return (error); 339 if ((error = getsock(p, *(int *)data, &fp)) != 0) 340 return (error); 341 if (syslogf) 342 FRELE(syslogf, p); 343 syslogf = fp; 344 break; 345 346 default: 347 return (ENOTTY); 348 } 349 return (0); 350 } 351 352 int 353 sys_sendsyslog(struct proc *p, void *v, register_t *retval) 354 { 355 struct sys_sendsyslog_args /* { 356 syscallarg(const void *) buf; 357 syscallarg(size_t) nbyte; 358 } */ *uap = v; 359 int error; 360 #ifndef SMALL_KERNEL 361 static int dropped_count, orig_error; 362 int len; 363 char buf[64]; 364 365 if (dropped_count) { 366 len = snprintf(buf, sizeof(buf), 367 "<%d> sendsyslog: dropped %d message%s, error %d", 368 LOG_KERN|LOG_WARNING, dropped_count, 369 dropped_count == 1 ? "" : "s", orig_error); 370 error = dosendsyslog(p, buf, MIN((size_t)len, sizeof(buf) - 1), 371 UIO_SYSSPACE); 372 if (error) { 373 dropped_count++; 374 return (error); 375 } 376 dropped_count = 0; 377 } 378 #endif 379 error = dosendsyslog(p, SCARG(uap, buf), SCARG(uap, nbyte), 380 UIO_USERSPACE); 381 #ifndef SMALL_KERNEL 382 if (error) { 383 dropped_count++; 384 orig_error = error; 385 } 386 #endif 387 return (error); 388 } 389 390 int 391 dosendsyslog(struct proc *p, const char *buf, size_t nbyte, enum uio_seg sflg) 392 { 393 #ifdef KTRACE 394 struct iovec *ktriov = NULL; 395 int iovlen; 396 #endif 397 struct iovec aiov; 398 struct uio auio; 399 struct file *f; 400 size_t len; 401 int error; 402 403 if (syslogf == NULL) 404 return (ENOTCONN); 405 f = syslogf; 406 FREF(f); 407 408 aiov.iov_base = (char *)buf; 409 aiov.iov_len = nbyte; 410 auio.uio_iov = &aiov; 411 auio.uio_iovcnt = 1; 412 auio.uio_segflg = sflg; 413 auio.uio_rw = UIO_WRITE; 414 auio.uio_procp = p; 415 auio.uio_offset = 0; 416 auio.uio_resid = aiov.iov_len; 417 #ifdef KTRACE 418 if (KTRPOINT(p, KTR_GENIO)) { 419 ktriov = mallocarray(auio.uio_iovcnt, sizeof(struct iovec), 420 M_TEMP, M_WAITOK); 421 iovlen = auio.uio_iovcnt * sizeof (struct iovec); 422 423 memcpy(ktriov, auio.uio_iov, iovlen); 424 } 425 #endif 426 427 len = auio.uio_resid; 428 error = sosend(f->f_data, NULL, &auio, NULL, NULL, 0); 429 if (error == 0) 430 len -= auio.uio_resid; 431 432 #ifdef KTRACE 433 if (ktriov != NULL) { 434 if (error == 0) 435 ktrgenio(p, -1, UIO_WRITE, ktriov, len); 436 free(ktriov, M_TEMP, iovlen); 437 } 438 #endif 439 FRELE(f, p); 440 return error; 441 } 442