1 /* $OpenBSD: subr_log.c,v 1.77 2023/07/14 07:07:08 claudio 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/malloc.h> 50 #include <sys/filedesc.h> 51 #include <sys/socket.h> 52 #include <sys/socketvar.h> 53 #include <sys/fcntl.h> 54 #include <sys/mutex.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 /* 73 * Locking: 74 * L log_mtx 75 */ 76 struct logsoftc { 77 int sc_state; /* [L] see above for possibilities */ 78 struct selinfo sc_selp; /* process waiting on select call */ 79 struct sigio_ref sc_sigio; /* async I/O registration */ 80 int sc_need_wakeup; /* if set, wake up waiters */ 81 struct timeout sc_tick; /* wakeup poll timeout */ 82 } logsoftc; 83 84 int log_open; /* also used in log() */ 85 int msgbufmapped; /* is the message buffer mapped */ 86 struct msgbuf *msgbufp; /* the mapped buffer, itself. */ 87 struct msgbuf *consbufp; /* console message buffer. */ 88 89 struct file *syslogf; 90 struct rwlock syslogf_rwlock = RWLOCK_INITIALIZER("syslogf"); 91 92 /* 93 * Lock that serializes access to log message buffers. 94 * This should be kept as a leaf lock in order not to constrain where 95 * printf(9) can be used. 96 */ 97 struct mutex log_mtx = 98 MUTEX_INITIALIZER_FLAGS(IPL_HIGH, "logmtx", MTX_NOWITNESS); 99 100 void filt_logrdetach(struct knote *kn); 101 int filt_logread(struct knote *kn, long hint); 102 103 const struct filterops logread_filtops = { 104 .f_flags = FILTEROP_ISFD, 105 .f_attach = NULL, 106 .f_detach = filt_logrdetach, 107 .f_event = filt_logread, 108 }; 109 110 int dosendsyslog(struct proc *, const char *, size_t, int, enum uio_seg); 111 void logtick(void *); 112 size_t msgbuf_getlen(struct msgbuf *); 113 void msgbuf_putchar_locked(struct msgbuf *, const char); 114 115 void 116 initmsgbuf(caddr_t buf, size_t bufsize) 117 { 118 struct msgbuf *mbp; 119 long new_bufs; 120 121 /* Sanity-check the given size. */ 122 if (bufsize < sizeof(struct msgbuf)) 123 return; 124 125 mbp = msgbufp = (struct msgbuf *)buf; 126 127 new_bufs = bufsize - offsetof(struct msgbuf, msg_bufc); 128 if ((mbp->msg_magic != MSG_MAGIC) || (mbp->msg_bufs != new_bufs) || 129 (mbp->msg_bufr < 0) || (mbp->msg_bufr >= mbp->msg_bufs) || 130 (mbp->msg_bufx < 0) || (mbp->msg_bufx >= mbp->msg_bufs)) { 131 /* 132 * If the buffer magic number is wrong, has changed 133 * size (which shouldn't happen often), or is 134 * internally inconsistent, initialize it. 135 */ 136 137 memset(buf, 0, bufsize); 138 mbp->msg_magic = MSG_MAGIC; 139 mbp->msg_bufs = new_bufs; 140 } 141 142 /* 143 * Always start new buffer data on a new line. 144 * Avoid using log_mtx because mutexes do not work during early boot 145 * on some architectures. 146 */ 147 if (mbp->msg_bufx > 0 && mbp->msg_bufc[mbp->msg_bufx - 1] != '\n') 148 msgbuf_putchar_locked(mbp, '\n'); 149 150 /* mark it as ready for use. */ 151 msgbufmapped = 1; 152 } 153 154 void 155 initconsbuf(void) 156 { 157 /* Set up a buffer to collect /dev/console output */ 158 consbufp = malloc(CONSBUFSIZE, M_TTYS, M_WAITOK | M_ZERO); 159 consbufp->msg_magic = MSG_MAGIC; 160 consbufp->msg_bufs = CONSBUFSIZE - offsetof(struct msgbuf, msg_bufc); 161 } 162 163 void 164 msgbuf_putchar(struct msgbuf *mbp, const char c) 165 { 166 if (mbp->msg_magic != MSG_MAGIC) 167 /* Nothing we can do */ 168 return; 169 170 mtx_enter(&log_mtx); 171 msgbuf_putchar_locked(mbp, c); 172 mtx_leave(&log_mtx); 173 } 174 175 void 176 msgbuf_putchar_locked(struct msgbuf *mbp, const char c) 177 { 178 mbp->msg_bufc[mbp->msg_bufx++] = c; 179 if (mbp->msg_bufx < 0 || mbp->msg_bufx >= mbp->msg_bufs) 180 mbp->msg_bufx = 0; 181 /* If the buffer is full, keep the most recent data. */ 182 if (mbp->msg_bufr == mbp->msg_bufx) { 183 if (++mbp->msg_bufr >= mbp->msg_bufs) 184 mbp->msg_bufr = 0; 185 mbp->msg_bufd++; 186 } 187 } 188 189 size_t 190 msgbuf_getlen(struct msgbuf *mbp) 191 { 192 long len; 193 194 mtx_enter(&log_mtx); 195 len = mbp->msg_bufx - mbp->msg_bufr; 196 if (len < 0) 197 len += mbp->msg_bufs; 198 mtx_leave(&log_mtx); 199 return (len); 200 } 201 202 int 203 logopen(dev_t dev, int flags, int mode, struct proc *p) 204 { 205 if (log_open) 206 return (EBUSY); 207 log_open = 1; 208 sigio_init(&logsoftc.sc_sigio); 209 timeout_set(&logsoftc.sc_tick, logtick, NULL); 210 timeout_add_msec(&logsoftc.sc_tick, LOG_TICK); 211 return (0); 212 } 213 214 int 215 logclose(dev_t dev, int flag, int mode, struct proc *p) 216 { 217 struct file *fp; 218 219 rw_enter_write(&syslogf_rwlock); 220 fp = syslogf; 221 syslogf = NULL; 222 rw_exit(&syslogf_rwlock); 223 224 if (fp) 225 FRELE(fp, p); 226 log_open = 0; 227 timeout_del(&logsoftc.sc_tick); 228 logsoftc.sc_state = 0; 229 sigio_free(&logsoftc.sc_sigio); 230 return (0); 231 } 232 233 int 234 logread(dev_t dev, struct uio *uio, int flag) 235 { 236 struct msgbuf *mbp = msgbufp; 237 size_t l, rpos; 238 int error = 0; 239 240 mtx_enter(&log_mtx); 241 while (mbp->msg_bufr == mbp->msg_bufx) { 242 if (flag & IO_NDELAY) { 243 error = EWOULDBLOCK; 244 goto out; 245 } 246 logsoftc.sc_state |= LOG_RDWAIT; 247 mtx_leave(&log_mtx); 248 /* 249 * Set up and enter sleep manually instead of using msleep() 250 * to keep log_mtx as a leaf lock. 251 */ 252 sleep_setup(mbp, LOG_RDPRI | PCATCH, "klog"); 253 error = sleep_finish(0, logsoftc.sc_state & LOG_RDWAIT); 254 mtx_enter(&log_mtx); 255 if (error) 256 goto out; 257 } 258 259 if (mbp->msg_bufd > 0) { 260 char buf[64]; 261 long ndropped; 262 263 ndropped = mbp->msg_bufd; 264 mtx_leave(&log_mtx); 265 l = snprintf(buf, sizeof(buf), 266 "<%d>klog: dropped %ld byte%s, message buffer full\n", 267 LOG_KERN|LOG_WARNING, ndropped, 268 ndropped == 1 ? "" : "s"); 269 error = uiomove(buf, ulmin(l, sizeof(buf) - 1), uio); 270 mtx_enter(&log_mtx); 271 if (error) 272 goto out; 273 mbp->msg_bufd -= ndropped; 274 } 275 276 while (uio->uio_resid > 0) { 277 if (mbp->msg_bufx >= mbp->msg_bufr) 278 l = mbp->msg_bufx - mbp->msg_bufr; 279 else 280 l = mbp->msg_bufs - mbp->msg_bufr; 281 l = ulmin(l, uio->uio_resid); 282 if (l == 0) 283 break; 284 rpos = mbp->msg_bufr; 285 mtx_leave(&log_mtx); 286 /* Ignore that concurrent readers may consume the same data. */ 287 error = uiomove(&mbp->msg_bufc[rpos], l, uio); 288 mtx_enter(&log_mtx); 289 if (error) 290 break; 291 mbp->msg_bufr += l; 292 if (mbp->msg_bufr < 0 || mbp->msg_bufr >= mbp->msg_bufs) 293 mbp->msg_bufr = 0; 294 } 295 out: 296 mtx_leave(&log_mtx); 297 return (error); 298 } 299 300 int 301 logkqfilter(dev_t dev, struct knote *kn) 302 { 303 struct klist *klist; 304 int s; 305 306 switch (kn->kn_filter) { 307 case EVFILT_READ: 308 klist = &logsoftc.sc_selp.si_note; 309 kn->kn_fop = &logread_filtops; 310 break; 311 default: 312 return (EINVAL); 313 } 314 315 kn->kn_hook = (void *)msgbufp; 316 317 s = splhigh(); 318 klist_insert_locked(klist, kn); 319 splx(s); 320 321 return (0); 322 } 323 324 void 325 filt_logrdetach(struct knote *kn) 326 { 327 int s; 328 329 s = splhigh(); 330 klist_remove_locked(&logsoftc.sc_selp.si_note, kn); 331 splx(s); 332 } 333 334 int 335 filt_logread(struct knote *kn, long hint) 336 { 337 struct msgbuf *mbp = kn->kn_hook; 338 339 kn->kn_data = msgbuf_getlen(mbp); 340 return (kn->kn_data != 0); 341 } 342 343 void 344 logwakeup(void) 345 { 346 /* 347 * The actual wakeup has to be deferred because logwakeup() can be 348 * called in very varied contexts. 349 * Keep the print routines usable in as many situations as possible 350 * by not using locking here. 351 */ 352 353 /* 354 * Ensure that preceding stores become visible to other CPUs 355 * before the flag. 356 */ 357 membar_producer(); 358 359 logsoftc.sc_need_wakeup = 1; 360 } 361 362 void 363 logtick(void *arg) 364 { 365 int state; 366 367 if (!log_open) 368 return; 369 370 if (!logsoftc.sc_need_wakeup) 371 goto out; 372 logsoftc.sc_need_wakeup = 0; 373 374 /* 375 * sc_need_wakeup has to be cleared before handling the wakeup. 376 * Visiting log_mtx ensures the proper order. 377 */ 378 379 mtx_enter(&log_mtx); 380 state = logsoftc.sc_state; 381 if (logsoftc.sc_state & LOG_RDWAIT) 382 logsoftc.sc_state &= ~LOG_RDWAIT; 383 mtx_leave(&log_mtx); 384 385 selwakeup(&logsoftc.sc_selp); 386 if (state & LOG_ASYNC) 387 pgsigio(&logsoftc.sc_sigio, SIGIO, 0); 388 if (state & LOG_RDWAIT) 389 wakeup(msgbufp); 390 out: 391 timeout_add_msec(&logsoftc.sc_tick, LOG_TICK); 392 } 393 394 int 395 logioctl(dev_t dev, u_long com, caddr_t data, int flag, struct proc *p) 396 { 397 struct file *fp, *newfp; 398 int error; 399 400 switch (com) { 401 402 /* return number of characters immediately available */ 403 case FIONREAD: 404 *(int *)data = (int)msgbuf_getlen(msgbufp); 405 break; 406 407 case FIONBIO: 408 break; 409 410 case FIOASYNC: 411 mtx_enter(&log_mtx); 412 if (*(int *)data) 413 logsoftc.sc_state |= LOG_ASYNC; 414 else 415 logsoftc.sc_state &= ~LOG_ASYNC; 416 mtx_leave(&log_mtx); 417 break; 418 419 case FIOSETOWN: 420 case TIOCSPGRP: 421 return (sigio_setown(&logsoftc.sc_sigio, com, data)); 422 423 case FIOGETOWN: 424 case TIOCGPGRP: 425 sigio_getown(&logsoftc.sc_sigio, com, data); 426 break; 427 428 case LIOCSFD: 429 if ((error = suser(p)) != 0) 430 return (error); 431 if ((error = getsock(p, *(int *)data, &newfp)) != 0) 432 return (error); 433 434 rw_enter_write(&syslogf_rwlock); 435 fp = syslogf; 436 syslogf = newfp; 437 rw_exit(&syslogf_rwlock); 438 439 if (fp) 440 FRELE(fp, p); 441 break; 442 443 default: 444 return (ENOTTY); 445 } 446 return (0); 447 } 448 449 /* 450 * If syslogd is not running, temporarily store a limited amount of messages 451 * in kernel. After log stash is full, drop messages and count them. When 452 * syslogd is available again, next log message will flush the stashed 453 * messages and insert a message with drop count. Calls to malloc(9) and 454 * copyin(9) may sleep, protect data structures with rwlock. 455 */ 456 457 #define LOGSTASH_SIZE 100 458 struct logstash_message { 459 char *lgs_buffer; 460 size_t lgs_size; 461 } logstash_messages[LOGSTASH_SIZE]; 462 463 struct logstash_message *logstash_in = &logstash_messages[0]; 464 struct logstash_message *logstash_out = &logstash_messages[0]; 465 466 struct rwlock logstash_rwlock = RWLOCK_INITIALIZER("logstash"); 467 468 int logstash_dropped, logstash_error, logstash_pid; 469 470 int logstash_insert(const char *, size_t, int, pid_t); 471 void logstash_remove(void); 472 int logstash_sendsyslog(struct proc *); 473 474 static inline int 475 logstash_full(void) 476 { 477 rw_assert_anylock(&logstash_rwlock); 478 479 return logstash_out->lgs_buffer != NULL && 480 logstash_in == logstash_out; 481 } 482 483 static inline void 484 logstash_increment(struct logstash_message **msg) 485 { 486 rw_assert_wrlock(&logstash_rwlock); 487 488 KASSERT((*msg) >= &logstash_messages[0]); 489 KASSERT((*msg) < &logstash_messages[LOGSTASH_SIZE]); 490 if ((*msg) == &logstash_messages[LOGSTASH_SIZE - 1]) 491 (*msg) = &logstash_messages[0]; 492 else 493 (*msg)++; 494 } 495 496 int 497 logstash_insert(const char *buf, size_t nbyte, int logerror, pid_t pid) 498 { 499 int error; 500 501 rw_enter_write(&logstash_rwlock); 502 503 if (logstash_full()) { 504 if (logstash_dropped == 0) { 505 logstash_error = logerror; 506 logstash_pid = pid; 507 } 508 logstash_dropped++; 509 510 rw_exit(&logstash_rwlock); 511 return (0); 512 } 513 514 logstash_in->lgs_buffer = malloc(nbyte, M_LOG, M_WAITOK); 515 error = copyin(buf, logstash_in->lgs_buffer, nbyte); 516 if (error) { 517 free(logstash_in->lgs_buffer, M_LOG, nbyte); 518 logstash_in->lgs_buffer = NULL; 519 520 rw_exit(&logstash_rwlock); 521 return (error); 522 } 523 logstash_in->lgs_size = nbyte; 524 logstash_increment(&logstash_in); 525 526 rw_exit(&logstash_rwlock); 527 return (0); 528 } 529 530 void 531 logstash_remove(void) 532 { 533 rw_assert_wrlock(&logstash_rwlock); 534 535 KASSERT(logstash_out->lgs_buffer != NULL); 536 free(logstash_out->lgs_buffer, M_LOG, logstash_out->lgs_size); 537 logstash_out->lgs_buffer = NULL; 538 logstash_increment(&logstash_out); 539 540 /* Insert dropped message in sequence where messages were dropped. */ 541 if (logstash_dropped) { 542 size_t l, nbyte; 543 char buf[80]; 544 545 l = snprintf(buf, sizeof(buf), 546 "<%d>sendsyslog: dropped %d message%s, error %d, pid %d", 547 LOG_KERN|LOG_WARNING, logstash_dropped, 548 logstash_dropped == 1 ? "" : "s", 549 logstash_error, logstash_pid); 550 logstash_dropped = 0; 551 logstash_error = 0; 552 logstash_pid = 0; 553 554 /* Cannot fail, we have just freed a slot. */ 555 KASSERT(!logstash_full()); 556 nbyte = ulmin(l, sizeof(buf) - 1); 557 logstash_in->lgs_buffer = malloc(nbyte, M_LOG, M_WAITOK); 558 memcpy(logstash_in->lgs_buffer, buf, nbyte); 559 logstash_in->lgs_size = nbyte; 560 logstash_increment(&logstash_in); 561 } 562 } 563 564 int 565 logstash_sendsyslog(struct proc *p) 566 { 567 int error; 568 569 rw_enter_write(&logstash_rwlock); 570 571 while (logstash_out->lgs_buffer != NULL) { 572 error = dosendsyslog(p, logstash_out->lgs_buffer, 573 logstash_out->lgs_size, 0, UIO_SYSSPACE); 574 if (error) { 575 rw_exit(&logstash_rwlock); 576 return (error); 577 } 578 logstash_remove(); 579 } 580 581 rw_exit(&logstash_rwlock); 582 return (0); 583 } 584 585 /* 586 * Send syslog(3) message from userland to socketpair(2) created by syslogd(8). 587 * Store message in kernel log stash for later if syslogd(8) is not available 588 * or sending fails. Send to console if LOG_CONS is set and syslogd(8) socket 589 * does not exist. 590 */ 591 592 int 593 sys_sendsyslog(struct proc *p, void *v, register_t *retval) 594 { 595 struct sys_sendsyslog_args /* { 596 syscallarg(const char *) buf; 597 syscallarg(size_t) nbyte; 598 syscallarg(int) flags; 599 } */ *uap = v; 600 size_t nbyte; 601 int error; 602 603 nbyte = SCARG(uap, nbyte); 604 if (nbyte > LOG_MAXLINE) 605 nbyte = LOG_MAXLINE; 606 607 logstash_sendsyslog(p); 608 error = dosendsyslog(p, SCARG(uap, buf), nbyte, SCARG(uap, flags), 609 UIO_USERSPACE); 610 if (error && error != EFAULT) 611 logstash_insert(SCARG(uap, buf), nbyte, error, p->p_p->ps_pid); 612 return (error); 613 } 614 615 int 616 dosendsyslog(struct proc *p, const char *buf, size_t nbyte, int flags, 617 enum uio_seg sflg) 618 { 619 #ifdef KTRACE 620 struct iovec ktriov; 621 #endif 622 struct file *fp; 623 char pri[6], *kbuf; 624 struct iovec aiov; 625 struct uio auio; 626 size_t i, len; 627 int error; 628 629 /* Global variable syslogf may change during sleep, use local copy. */ 630 rw_enter_read(&syslogf_rwlock); 631 fp = syslogf; 632 if (fp) 633 FREF(fp); 634 rw_exit(&syslogf_rwlock); 635 636 if (fp == NULL) { 637 if (!ISSET(flags, LOG_CONS)) 638 return (ENOTCONN); 639 /* 640 * Strip off syslog priority when logging to console. 641 * LOG_PRIMASK | LOG_FACMASK is 0x03ff, so at most 4 642 * decimal digits may appear in priority as <1023>. 643 */ 644 len = MIN(nbyte, sizeof(pri)); 645 if (sflg == UIO_USERSPACE) { 646 if ((error = copyin(buf, pri, len))) 647 return (error); 648 } else 649 memcpy(pri, buf, len); 650 if (0 < len && pri[0] == '<') { 651 for (i = 1; i < len; i++) { 652 if (pri[i] < '0' || pri[i] > '9') 653 break; 654 } 655 if (i < len && pri[i] == '>') { 656 i++; 657 /* There must be at least one digit <0>. */ 658 if (i >= 3) { 659 buf += i; 660 nbyte -= i; 661 } 662 } 663 } 664 } 665 666 aiov.iov_base = (char *)buf; 667 aiov.iov_len = nbyte; 668 auio.uio_iov = &aiov; 669 auio.uio_iovcnt = 1; 670 auio.uio_segflg = sflg; 671 auio.uio_rw = UIO_WRITE; 672 auio.uio_procp = p; 673 auio.uio_offset = 0; 674 auio.uio_resid = aiov.iov_len; 675 #ifdef KTRACE 676 if (sflg == UIO_USERSPACE && KTRPOINT(p, KTR_GENIO)) 677 ktriov = aiov; 678 else 679 ktriov.iov_len = 0; 680 #endif 681 682 len = auio.uio_resid; 683 if (fp) { 684 int flags = (fp->f_flag & FNONBLOCK) ? MSG_DONTWAIT : 0; 685 error = sosend(fp->f_data, NULL, &auio, NULL, NULL, flags); 686 if (error == 0) 687 len -= auio.uio_resid; 688 } else { 689 KERNEL_LOCK(); 690 if (constty || cn_devvp) { 691 error = cnwrite(0, &auio, 0); 692 if (error == 0) 693 len -= auio.uio_resid; 694 aiov.iov_base = "\r\n"; 695 aiov.iov_len = 2; 696 auio.uio_iov = &aiov; 697 auio.uio_iovcnt = 1; 698 auio.uio_segflg = UIO_SYSSPACE; 699 auio.uio_rw = UIO_WRITE; 700 auio.uio_procp = p; 701 auio.uio_offset = 0; 702 auio.uio_resid = aiov.iov_len; 703 cnwrite(0, &auio, 0); 704 } else { 705 /* XXX console redirection breaks down... */ 706 if (sflg == UIO_USERSPACE) { 707 kbuf = malloc(len, M_TEMP, M_WAITOK); 708 error = copyin(aiov.iov_base, kbuf, len); 709 } else { 710 kbuf = aiov.iov_base; 711 error = 0; 712 } 713 if (error == 0) 714 for (i = 0; i < len; i++) { 715 if (kbuf[i] == '\0') 716 break; 717 cnputc(kbuf[i]); 718 auio.uio_resid--; 719 } 720 if (sflg == UIO_USERSPACE) 721 free(kbuf, M_TEMP, len); 722 if (error == 0) 723 len -= auio.uio_resid; 724 cnputc('\n'); 725 } 726 KERNEL_UNLOCK(); 727 } 728 729 #ifdef KTRACE 730 if (error == 0 && ktriov.iov_len != 0) 731 ktrgenio(p, -1, UIO_WRITE, &ktriov, len); 732 #endif 733 if (fp) 734 FRELE(fp, p); 735 else if (error != EFAULT) 736 error = ENOTCONN; 737 return (error); 738 } 739