1 /* $OpenBSD: subr_log.c,v 1.63 2020/01/08 16:27:41 visa 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/tty.h> 47 #include <sys/signalvar.h> 48 #include <sys/syslog.h> 49 #include <sys/poll.h> 50 #include <sys/malloc.h> 51 #include <sys/filedesc.h> 52 #include <sys/socket.h> 53 #include <sys/socketvar.h> 54 #include <sys/fcntl.h> 55 #include <sys/timeout.h> 56 57 #ifdef KTRACE 58 #include <sys/ktrace.h> 59 #endif 60 61 #include <sys/mount.h> 62 #include <sys/syscallargs.h> 63 64 #include <dev/cons.h> 65 66 #define LOG_RDPRI (PZERO + 1) 67 #define LOG_TICK 50 /* log tick interval in msec */ 68 69 #define LOG_ASYNC 0x04 70 #define LOG_RDWAIT 0x08 71 72 struct logsoftc { 73 int sc_state; /* see above for possibilities */ 74 struct selinfo sc_selp; /* process waiting on select call */ 75 struct sigio_ref sc_sigio; /* async I/O registration */ 76 int sc_need_wakeup; /* if set, wake up waiters */ 77 struct timeout sc_tick; /* wakeup poll timeout */ 78 } logsoftc; 79 80 int log_open; /* also used in log() */ 81 int msgbufmapped; /* is the message buffer mapped */ 82 struct msgbuf *msgbufp; /* the mapped buffer, itself. */ 83 struct msgbuf *consbufp; /* console message buffer. */ 84 struct file *syslogf; 85 86 void filt_logrdetach(struct knote *kn); 87 int filt_logread(struct knote *kn, long hint); 88 89 const struct filterops logread_filtops = { 90 .f_isfd = 1, 91 .f_attach = NULL, 92 .f_detach = filt_logrdetach, 93 .f_event = filt_logread, 94 }; 95 96 int dosendsyslog(struct proc *, const char *, size_t, int, enum uio_seg); 97 void logtick(void *); 98 99 void 100 initmsgbuf(caddr_t buf, size_t bufsize) 101 { 102 struct msgbuf *mbp; 103 long new_bufs; 104 105 /* Sanity-check the given size. */ 106 if (bufsize < sizeof(struct msgbuf)) 107 return; 108 109 mbp = msgbufp = (struct msgbuf *)buf; 110 111 new_bufs = bufsize - offsetof(struct msgbuf, msg_bufc); 112 if ((mbp->msg_magic != MSG_MAGIC) || (mbp->msg_bufs != new_bufs) || 113 (mbp->msg_bufr < 0) || (mbp->msg_bufr >= mbp->msg_bufs) || 114 (mbp->msg_bufx < 0) || (mbp->msg_bufx >= mbp->msg_bufs)) { 115 /* 116 * If the buffer magic number is wrong, has changed 117 * size (which shouldn't happen often), or is 118 * internally inconsistent, initialize it. 119 */ 120 121 memset(buf, 0, bufsize); 122 mbp->msg_magic = MSG_MAGIC; 123 mbp->msg_bufs = new_bufs; 124 } 125 126 /* Always start new buffer data on a new line. */ 127 if (mbp->msg_bufx > 0 && mbp->msg_bufc[mbp->msg_bufx - 1] != '\n') 128 msgbuf_putchar(msgbufp, '\n'); 129 130 /* mark it as ready for use. */ 131 msgbufmapped = 1; 132 } 133 134 void 135 initconsbuf(void) 136 { 137 /* Set up a buffer to collect /dev/console output */ 138 consbufp = malloc(CONSBUFSIZE, M_TTYS, M_WAITOK | M_ZERO); 139 consbufp->msg_magic = MSG_MAGIC; 140 consbufp->msg_bufs = CONSBUFSIZE - offsetof(struct msgbuf, msg_bufc); 141 } 142 143 void 144 msgbuf_putchar(struct msgbuf *mbp, const char c) 145 { 146 int s; 147 148 if (mbp->msg_magic != MSG_MAGIC) 149 /* Nothing we can do */ 150 return; 151 152 s = splhigh(); 153 mbp->msg_bufc[mbp->msg_bufx++] = c; 154 mbp->msg_bufl = lmin(mbp->msg_bufl+1, mbp->msg_bufs); 155 if (mbp->msg_bufx < 0 || mbp->msg_bufx >= mbp->msg_bufs) 156 mbp->msg_bufx = 0; 157 /* If the buffer is full, keep the most recent data. */ 158 if (mbp->msg_bufr == mbp->msg_bufx) { 159 if (++mbp->msg_bufr >= mbp->msg_bufs) 160 mbp->msg_bufr = 0; 161 mbp->msg_bufd++; 162 } 163 splx(s); 164 } 165 166 int 167 logopen(dev_t dev, int flags, int mode, struct proc *p) 168 { 169 if (log_open) 170 return (EBUSY); 171 log_open = 1; 172 sigio_init(&logsoftc.sc_sigio); 173 timeout_set(&logsoftc.sc_tick, logtick, NULL); 174 timeout_add_msec(&logsoftc.sc_tick, LOG_TICK); 175 return (0); 176 } 177 178 int 179 logclose(dev_t dev, int flag, int mode, struct proc *p) 180 { 181 struct file *fp; 182 183 fp = syslogf; 184 syslogf = NULL; 185 if (fp) 186 FRELE(fp, p); 187 log_open = 0; 188 timeout_del(&logsoftc.sc_tick); 189 logsoftc.sc_state = 0; 190 sigio_free(&logsoftc.sc_sigio); 191 return (0); 192 } 193 194 int 195 logread(dev_t dev, struct uio *uio, int flag) 196 { 197 struct msgbuf *mbp = msgbufp; 198 size_t l; 199 int s, error = 0; 200 201 s = splhigh(); 202 while (mbp->msg_bufr == mbp->msg_bufx) { 203 if (flag & IO_NDELAY) { 204 error = EWOULDBLOCK; 205 goto out; 206 } 207 logsoftc.sc_state |= LOG_RDWAIT; 208 error = tsleep(mbp, LOG_RDPRI | PCATCH, 209 "klog", 0); 210 if (error) 211 goto out; 212 } 213 logsoftc.sc_state &= ~LOG_RDWAIT; 214 215 if (mbp->msg_bufd > 0) { 216 char buf[64]; 217 218 l = snprintf(buf, sizeof(buf), 219 "<%d>klog: dropped %ld byte%s, message buffer full\n", 220 LOG_KERN|LOG_WARNING, mbp->msg_bufd, 221 mbp->msg_bufd == 1 ? "" : "s"); 222 error = uiomove(buf, ulmin(l, sizeof(buf) - 1), uio); 223 if (error) 224 goto out; 225 mbp->msg_bufd = 0; 226 } 227 228 while (uio->uio_resid > 0) { 229 if (mbp->msg_bufx >= mbp->msg_bufr) 230 l = mbp->msg_bufx - mbp->msg_bufr; 231 else 232 l = mbp->msg_bufs - mbp->msg_bufr; 233 l = ulmin(l, uio->uio_resid); 234 if (l == 0) 235 break; 236 error = uiomove(&mbp->msg_bufc[mbp->msg_bufr], l, uio); 237 if (error) 238 break; 239 mbp->msg_bufr += l; 240 if (mbp->msg_bufr < 0 || mbp->msg_bufr >= mbp->msg_bufs) 241 mbp->msg_bufr = 0; 242 } 243 out: 244 splx(s); 245 return (error); 246 } 247 248 int 249 logpoll(dev_t dev, int events, struct proc *p) 250 { 251 int s, revents = 0; 252 253 s = splhigh(); 254 if (events & (POLLIN | POLLRDNORM)) { 255 if (msgbufp->msg_bufr != msgbufp->msg_bufx) 256 revents |= events & (POLLIN | POLLRDNORM); 257 else 258 selrecord(p, &logsoftc.sc_selp); 259 } 260 splx(s); 261 return (revents); 262 } 263 264 int 265 logkqfilter(dev_t dev, struct knote *kn) 266 { 267 struct klist *klist; 268 int s; 269 270 switch (kn->kn_filter) { 271 case EVFILT_READ: 272 klist = &logsoftc.sc_selp.si_note; 273 kn->kn_fop = &logread_filtops; 274 break; 275 default: 276 return (EINVAL); 277 } 278 279 kn->kn_hook = (void *)msgbufp; 280 281 s = splhigh(); 282 SLIST_INSERT_HEAD(klist, kn, kn_selnext); 283 splx(s); 284 285 return (0); 286 } 287 288 void 289 filt_logrdetach(struct knote *kn) 290 { 291 int s; 292 293 s = splhigh(); 294 SLIST_REMOVE(&logsoftc.sc_selp.si_note, kn, knote, kn_selnext); 295 splx(s); 296 } 297 298 int 299 filt_logread(struct knote *kn, long hint) 300 { 301 struct msgbuf *p = (struct msgbuf *)kn->kn_hook; 302 int s, event = 0; 303 304 s = splhigh(); 305 kn->kn_data = (int)(p->msg_bufx - p->msg_bufr); 306 event = (p->msg_bufx != p->msg_bufr); 307 splx(s); 308 return (event); 309 } 310 311 void 312 logwakeup(void) 313 { 314 /* 315 * The actual wakeup has to be deferred because logwakeup() can be 316 * called in very varied contexts. 317 * Keep the print routines usable in as many situations as possible 318 * by not using locking here. 319 */ 320 321 /* 322 * Ensure that preceding stores become visible to other CPUs 323 * before the flag. 324 */ 325 membar_producer(); 326 327 logsoftc.sc_need_wakeup = 1; 328 } 329 330 void 331 logtick(void *arg) 332 { 333 if (!log_open) 334 return; 335 336 if (!logsoftc.sc_need_wakeup) 337 goto out; 338 logsoftc.sc_need_wakeup = 0; 339 340 /* 341 * sc_need_wakeup has to be cleared before handling the wakeup. 342 * This ensures that no wakeup is lost. 343 */ 344 membar_enter(); 345 346 selwakeup(&logsoftc.sc_selp); 347 if (logsoftc.sc_state & LOG_ASYNC) 348 pgsigio(&logsoftc.sc_sigio, SIGIO, 0); 349 if (logsoftc.sc_state & LOG_RDWAIT) { 350 wakeup(msgbufp); 351 logsoftc.sc_state &= ~LOG_RDWAIT; 352 } 353 out: 354 timeout_add_msec(&logsoftc.sc_tick, LOG_TICK); 355 } 356 357 int 358 logioctl(dev_t dev, u_long com, caddr_t data, int flag, struct proc *p) 359 { 360 struct file *fp; 361 long l; 362 int error, s; 363 364 switch (com) { 365 366 /* return number of characters immediately available */ 367 case FIONREAD: 368 s = splhigh(); 369 l = msgbufp->msg_bufx - msgbufp->msg_bufr; 370 splx(s); 371 if (l < 0) 372 l += msgbufp->msg_bufs; 373 *(int *)data = l; 374 break; 375 376 case FIONBIO: 377 break; 378 379 case FIOASYNC: 380 if (*(int *)data) 381 logsoftc.sc_state |= LOG_ASYNC; 382 else 383 logsoftc.sc_state &= ~LOG_ASYNC; 384 break; 385 386 case FIOSETOWN: 387 case TIOCSPGRP: 388 return (sigio_setown(&logsoftc.sc_sigio, com, data)); 389 390 case FIOGETOWN: 391 case TIOCGPGRP: 392 sigio_getown(&logsoftc.sc_sigio, com, data); 393 break; 394 395 case LIOCSFD: 396 if ((error = suser(p)) != 0) 397 return (error); 398 fp = syslogf; 399 if ((error = getsock(p, *(int *)data, &syslogf)) != 0) 400 return (error); 401 if (fp) 402 FRELE(fp, p); 403 break; 404 405 default: 406 return (ENOTTY); 407 } 408 return (0); 409 } 410 411 int 412 sys_sendsyslog(struct proc *p, void *v, register_t *retval) 413 { 414 struct sys_sendsyslog_args /* { 415 syscallarg(const char *) buf; 416 syscallarg(size_t) nbyte; 417 syscallarg(int) flags; 418 } */ *uap = v; 419 int error; 420 static int dropped_count, orig_error, orig_pid; 421 422 if (dropped_count) { 423 size_t l; 424 char buf[80]; 425 426 l = snprintf(buf, sizeof(buf), 427 "<%d>sendsyslog: dropped %d message%s, error %d, pid %d", 428 LOG_KERN|LOG_WARNING, dropped_count, 429 dropped_count == 1 ? "" : "s", orig_error, orig_pid); 430 error = dosendsyslog(p, buf, ulmin(l, sizeof(buf) - 1), 431 0, UIO_SYSSPACE); 432 if (error == 0) { 433 dropped_count = 0; 434 orig_error = 0; 435 orig_pid = 0; 436 } 437 } 438 error = dosendsyslog(p, SCARG(uap, buf), SCARG(uap, nbyte), 439 SCARG(uap, flags), UIO_USERSPACE); 440 if (error) { 441 dropped_count++; 442 orig_error = error; 443 orig_pid = p->p_p->ps_pid; 444 } 445 return (error); 446 } 447 448 int 449 dosendsyslog(struct proc *p, const char *buf, size_t nbyte, int flags, 450 enum uio_seg sflg) 451 { 452 #ifdef KTRACE 453 struct iovec ktriov; 454 #endif 455 struct file *fp; 456 char pri[6], *kbuf; 457 struct iovec aiov; 458 struct uio auio; 459 size_t i, len; 460 int error; 461 462 if (nbyte > LOG_MAXLINE) 463 nbyte = LOG_MAXLINE; 464 465 /* Global variable syslogf may change during sleep, use local copy. */ 466 fp = syslogf; 467 if (fp) 468 FREF(fp); 469 else if (!ISSET(flags, LOG_CONS)) 470 return (ENOTCONN); 471 else { 472 /* 473 * Strip off syslog priority when logging to console. 474 * LOG_PRIMASK | LOG_FACMASK is 0x03ff, so at most 4 475 * decimal digits may appear in priority as <1023>. 476 */ 477 len = MIN(nbyte, sizeof(pri)); 478 if (sflg == UIO_USERSPACE) { 479 if ((error = copyin(buf, pri, len))) 480 return (error); 481 } else 482 memcpy(pri, buf, len); 483 if (0 < len && pri[0] == '<') { 484 for (i = 1; i < len; i++) { 485 if (pri[i] < '0' || pri[i] > '9') 486 break; 487 } 488 if (i < len && pri[i] == '>') { 489 i++; 490 /* There must be at least one digit <0>. */ 491 if (i >= 3) { 492 buf += i; 493 nbyte -= i; 494 } 495 } 496 } 497 } 498 499 aiov.iov_base = (char *)buf; 500 aiov.iov_len = nbyte; 501 auio.uio_iov = &aiov; 502 auio.uio_iovcnt = 1; 503 auio.uio_segflg = sflg; 504 auio.uio_rw = UIO_WRITE; 505 auio.uio_procp = p; 506 auio.uio_offset = 0; 507 auio.uio_resid = aiov.iov_len; 508 #ifdef KTRACE 509 if (sflg == UIO_USERSPACE && KTRPOINT(p, KTR_GENIO)) 510 ktriov = aiov; 511 else 512 ktriov.iov_len = 0; 513 #endif 514 515 len = auio.uio_resid; 516 if (fp) { 517 int flags = (fp->f_flag & FNONBLOCK) ? MSG_DONTWAIT : 0; 518 error = sosend(fp->f_data, NULL, &auio, NULL, NULL, flags); 519 if (error == 0) 520 len -= auio.uio_resid; 521 } else if (constty || cn_devvp) { 522 error = cnwrite(0, &auio, 0); 523 if (error == 0) 524 len -= auio.uio_resid; 525 aiov.iov_base = "\r\n"; 526 aiov.iov_len = 2; 527 auio.uio_iov = &aiov; 528 auio.uio_iovcnt = 1; 529 auio.uio_segflg = UIO_SYSSPACE; 530 auio.uio_rw = UIO_WRITE; 531 auio.uio_procp = p; 532 auio.uio_offset = 0; 533 auio.uio_resid = aiov.iov_len; 534 cnwrite(0, &auio, 0); 535 } else { 536 /* XXX console redirection breaks down... */ 537 if (sflg == UIO_USERSPACE) { 538 kbuf = malloc(len, M_TEMP, M_WAITOK); 539 error = copyin(aiov.iov_base, kbuf, len); 540 } else { 541 kbuf = aiov.iov_base; 542 error = 0; 543 } 544 if (error == 0) 545 for (i = 0; i < len; i++) { 546 if (kbuf[i] == '\0') 547 break; 548 cnputc(kbuf[i]); 549 auio.uio_resid--; 550 } 551 if (sflg == UIO_USERSPACE) 552 free(kbuf, M_TEMP, len); 553 if (error == 0) 554 len -= auio.uio_resid; 555 cnputc('\n'); 556 } 557 558 #ifdef KTRACE 559 if (error == 0 && ktriov.iov_len != 0) 560 ktrgenio(p, -1, UIO_WRITE, &ktriov, len); 561 #endif 562 if (fp) 563 FRELE(fp, p); 564 else 565 error = ENOTCONN; 566 return (error); 567 } 568