1 /*- 2 * Copyright (c) 1986, 1988, 1991, 1993 3 * The Regents of the University of California. All rights reserved. 4 * (c) UNIX System Laboratories, Inc. 5 * All or some portions of this file are derived from material licensed 6 * to the University of California by American Telephone and Telegraph 7 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 8 * the permission of UNIX System Laboratories, Inc. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the University of 21 * California, Berkeley and its contributors. 22 * 4. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 * 38 * @(#)subr_prf.c 8.3 (Berkeley) 1/21/94 39 * $FreeBSD: src/sys/kern/subr_prf.c,v 1.61.2.5 2002/08/31 18:22:08 dwmalone Exp $ 40 * $DragonFly: src/sys/kern/subr_prf.c,v 1.17 2006/12/26 11:01:07 swildner Exp $ 41 */ 42 43 #include "opt_ddb.h" 44 45 #include <sys/param.h> 46 #include <sys/systm.h> 47 #include <sys/kernel.h> 48 #include <sys/msgbuf.h> 49 #include <sys/malloc.h> 50 #include <sys/proc.h> 51 #include <sys/tty.h> 52 #include <sys/tprintf.h> 53 #include <sys/stdint.h> 54 #include <sys/syslog.h> 55 #include <sys/cons.h> 56 #include <sys/uio.h> 57 #include <sys/sysctl.h> 58 #include <sys/lock.h> 59 #include <sys/ctype.h> 60 61 #ifdef DDB 62 #include <ddb/ddb.h> 63 #endif 64 65 /* 66 * Note that stdarg.h and the ANSI style va_start macro is used for both 67 * ANSI and traditional C compilers. We use the __ machine version to stay 68 * within the kernel header file set. 69 */ 70 #include <machine/stdarg.h> 71 72 #define TOCONS 0x01 73 #define TOTTY 0x02 74 #define TOLOG 0x04 75 76 /* Max number conversion buffer length: a u_quad_t in base 2, plus NUL byte. */ 77 #define MAXNBUF (sizeof(intmax_t) * NBBY + 1) 78 79 struct putchar_arg { 80 int flags; 81 int pri; 82 struct tty *tty; 83 }; 84 85 struct snprintf_arg { 86 char *str; 87 size_t remain; 88 }; 89 90 extern int log_open; 91 92 struct tty *constty; /* pointer to console "window" tty */ 93 94 static void (*v_putc)(int) = cnputc; /* routine to putc on virtual console */ 95 static void msglogchar(int c, int pri); 96 static void msgaddchar(int c, void *dummy); 97 static void kputchar (int ch, void *arg); 98 static char *ksprintn (char *nbuf, uintmax_t num, int base, int *lenp, 99 int upper); 100 static void snprintf_func (int ch, void *arg); 101 102 static int consintr = 1; /* Ok to handle console interrupts? */ 103 static int msgbufmapped; /* Set when safe to use msgbuf */ 104 int msgbuftrigger; 105 106 static int log_console_output = 1; 107 TUNABLE_INT("kern.log_console_output", &log_console_output); 108 SYSCTL_INT(_kern, OID_AUTO, log_console_output, CTLFLAG_RW, 109 &log_console_output, 0, ""); 110 111 static int unprivileged_read_msgbuf = 1; 112 SYSCTL_INT(_kern, OID_AUTO, unprivileged_read_msgbuf, CTLFLAG_RW, 113 &unprivileged_read_msgbuf, 0, 114 "Unprivileged processes may read the kernel message buffer"); 115 116 /* 117 * Warn that a system table is full. 118 */ 119 void 120 tablefull(const char *tab) 121 { 122 123 log(LOG_ERR, "%s: table is full\n", tab); 124 } 125 126 /* 127 * Uprintf prints to the controlling terminal for the current process. 128 */ 129 int 130 uprintf(const char *fmt, ...) 131 { 132 struct proc *p = curproc; 133 __va_list ap; 134 struct putchar_arg pca; 135 int retval = 0; 136 137 if (p && p->p_flag & P_CONTROLT && 138 p->p_session->s_ttyvp) { 139 __va_start(ap, fmt); 140 pca.tty = p->p_session->s_ttyp; 141 pca.flags = TOTTY; 142 143 retval = kvcprintf(fmt, kputchar, &pca, 10, ap); 144 __va_end(ap); 145 } 146 return (retval); 147 } 148 149 tpr_t 150 tprintf_open(struct proc *p) 151 { 152 153 if ((p->p_flag & P_CONTROLT) && p->p_session->s_ttyvp) { 154 sess_hold(p->p_session); 155 return ((tpr_t) p->p_session); 156 } 157 return ((tpr_t) NULL); 158 } 159 160 void 161 tprintf_close(tpr_t sess) 162 { 163 if (sess) 164 sess_rele((struct session *) sess); 165 } 166 167 /* 168 * tprintf prints on the controlling terminal associated 169 * with the given session. 170 */ 171 int 172 tprintf(tpr_t tpr, const char *fmt, ...) 173 { 174 struct session *sess = (struct session *)tpr; 175 struct tty *tp = NULL; 176 int flags = TOLOG; 177 __va_list ap; 178 struct putchar_arg pca; 179 int retval; 180 181 if (sess && sess->s_ttyvp && ttycheckoutq(sess->s_ttyp, 0)) { 182 flags |= TOTTY; 183 tp = sess->s_ttyp; 184 } 185 __va_start(ap, fmt); 186 pca.tty = tp; 187 pca.flags = flags; 188 pca.pri = LOG_INFO; 189 retval = kvcprintf(fmt, kputchar, &pca, 10, ap); 190 __va_end(ap); 191 msgbuftrigger = 1; 192 return (retval); 193 } 194 195 /* 196 * Ttyprintf displays a message on a tty; it should be used only by 197 * the tty driver, or anything that knows the underlying tty will not 198 * be revoke(2)'d away. Other callers should use tprintf. 199 */ 200 int 201 ttyprintf(struct tty *tp, const char *fmt, ...) 202 { 203 __va_list ap; 204 struct putchar_arg pca; 205 int retval; 206 207 __va_start(ap, fmt); 208 pca.tty = tp; 209 pca.flags = TOTTY; 210 retval = kvcprintf(fmt, kputchar, &pca, 10, ap); 211 __va_end(ap); 212 return (retval); 213 } 214 215 /* 216 * Log writes to the log buffer, and guarantees not to sleep (so can be 217 * called by interrupt routines). If there is no process reading the 218 * log yet, it writes to the console also. 219 */ 220 int 221 log(int level, const char *fmt, ...) 222 { 223 __va_list ap; 224 int retval; 225 struct putchar_arg pca; 226 227 pca.tty = NULL; 228 pca.pri = level; 229 pca.flags = log_open ? TOLOG : TOCONS; 230 231 __va_start(ap, fmt); 232 retval = kvcprintf(fmt, kputchar, &pca, 10, ap); 233 __va_end(ap); 234 235 msgbuftrigger = 1; 236 return (retval); 237 } 238 239 #define CONSCHUNK 128 240 241 void 242 log_console(struct uio *uio) 243 { 244 int c, i, error, iovlen, nl; 245 struct uio muio; 246 struct iovec *miov = NULL; 247 char *consbuffer; 248 int pri; 249 250 if (!log_console_output) 251 return; 252 253 pri = LOG_INFO | LOG_CONSOLE; 254 muio = *uio; 255 iovlen = uio->uio_iovcnt * sizeof (struct iovec); 256 MALLOC(miov, struct iovec *, iovlen, M_TEMP, M_WAITOK); 257 MALLOC(consbuffer, char *, CONSCHUNK, M_TEMP, M_WAITOK); 258 bcopy((caddr_t)muio.uio_iov, (caddr_t)miov, iovlen); 259 muio.uio_iov = miov; 260 uio = &muio; 261 262 nl = 0; 263 while (uio->uio_resid > 0) { 264 c = imin(uio->uio_resid, CONSCHUNK); 265 error = uiomove(consbuffer, c, uio); 266 if (error != 0) 267 break; 268 for (i = 0; i < c; i++) { 269 msglogchar(consbuffer[i], pri); 270 if (consbuffer[i] == '\n') 271 nl = 1; 272 else 273 nl = 0; 274 } 275 } 276 if (!nl) 277 msglogchar('\n', pri); 278 msgbuftrigger = 1; 279 FREE(miov, M_TEMP); 280 FREE(consbuffer, M_TEMP); 281 return; 282 } 283 284 /* 285 * Output to the console. 286 * 287 * NOT YET ENTIRELY MPSAFE 288 */ 289 int 290 kprintf(const char *fmt, ...) 291 { 292 __va_list ap; 293 int savintr; 294 struct putchar_arg pca; 295 int retval; 296 297 savintr = consintr; /* disable interrupts */ 298 consintr = 0; 299 __va_start(ap, fmt); 300 pca.tty = NULL; 301 pca.flags = TOCONS | TOLOG; 302 pca.pri = -1; 303 cons_lock(); 304 retval = kvcprintf(fmt, kputchar, &pca, 10, ap); 305 cons_unlock(); 306 __va_end(ap); 307 if (!panicstr) 308 msgbuftrigger = 1; 309 consintr = savintr; /* reenable interrupts */ 310 return (retval); 311 } 312 313 int 314 kvprintf(const char *fmt, __va_list ap) 315 { 316 int savintr; 317 struct putchar_arg pca; 318 int retval; 319 320 savintr = consintr; /* disable interrupts */ 321 consintr = 0; 322 pca.tty = NULL; 323 pca.flags = TOCONS | TOLOG; 324 pca.pri = -1; 325 cons_lock(); 326 retval = kvcprintf(fmt, kputchar, &pca, 10, ap); 327 cons_unlock(); 328 if (!panicstr) 329 msgbuftrigger = 1; 330 consintr = savintr; /* reenable interrupts */ 331 return (retval); 332 } 333 334 /* 335 * Print a character on console or users terminal. If destination is 336 * the console then the last bunch of characters are saved in msgbuf for 337 * inspection later. 338 * 339 * NOT YET ENTIRELY MPSAFE, EVEN WHEN LOGGING JUST TO THE SYSCONSOLE. 340 */ 341 static void 342 kputchar(int c, void *arg) 343 { 344 struct putchar_arg *ap = (struct putchar_arg*) arg; 345 int flags = ap->flags; 346 struct tty *tp = ap->tty; 347 if (panicstr) 348 constty = NULL; 349 if ((flags & TOCONS) && tp == NULL && constty) { 350 tp = constty; 351 flags |= TOTTY; 352 } 353 if ((flags & TOTTY) && tp && tputchar(c, tp) < 0 && 354 (flags & TOCONS) && tp == constty) 355 constty = NULL; 356 if ((flags & TOLOG)) 357 msglogchar(c, ap->pri); 358 if ((flags & TOCONS) && constty == NULL && c != '\0') 359 (*v_putc)(c); 360 } 361 362 /* 363 * Scaled down version of sprintf(3). 364 */ 365 int 366 ksprintf(char *buf, const char *cfmt, ...) 367 { 368 int retval; 369 __va_list ap; 370 371 __va_start(ap, cfmt); 372 retval = kvcprintf(cfmt, NULL, (void *)buf, 10, ap); 373 buf[retval] = '\0'; 374 __va_end(ap); 375 return (retval); 376 } 377 378 /* 379 * Scaled down version of vsprintf(3). 380 */ 381 int 382 kvsprintf(char *buf, const char *cfmt, __va_list ap) 383 { 384 int retval; 385 386 retval = kvcprintf(cfmt, NULL, (void *)buf, 10, ap); 387 buf[retval] = '\0'; 388 return (retval); 389 } 390 391 /* 392 * Scaled down version of snprintf(3). 393 */ 394 int 395 ksnprintf(char *str, size_t size, const char *format, ...) 396 { 397 int retval; 398 __va_list ap; 399 400 __va_start(ap, format); 401 retval = kvsnprintf(str, size, format, ap); 402 __va_end(ap); 403 return(retval); 404 } 405 406 /* 407 * Scaled down version of vsnprintf(3). 408 */ 409 int 410 kvsnprintf(char *str, size_t size, const char *format, __va_list ap) 411 { 412 struct snprintf_arg info; 413 int retval; 414 415 info.str = str; 416 info.remain = size; 417 retval = kvcprintf(format, snprintf_func, &info, 10, ap); 418 if (info.remain >= 1) 419 *info.str++ = '\0'; 420 return (retval); 421 } 422 423 static void 424 snprintf_func(int ch, void *arg) 425 { 426 struct snprintf_arg *const info = arg; 427 428 if (info->remain >= 2) { 429 *info->str++ = ch; 430 info->remain--; 431 } 432 } 433 434 /* 435 * Put a NUL-terminated ASCII number (base <= 36) in a buffer in reverse 436 * order; return an optional length and a pointer to the last character 437 * written in the buffer (i.e., the first character of the string). 438 * The buffer pointed to by `nbuf' must have length >= MAXNBUF. 439 */ 440 static char * 441 ksprintn(char *nbuf, uintmax_t num, int base, int *lenp, int upper) 442 { 443 char *p, c; 444 445 p = nbuf; 446 *p = '\0'; 447 do { 448 c = hex2ascii(num % base); 449 *++p = upper ? toupper(c) : c; 450 } while (num /= base); 451 if (lenp) 452 *lenp = p - nbuf; 453 return (p); 454 } 455 456 /* 457 * Scaled down version of printf(3). 458 * 459 * Two additional formats: 460 * 461 * The format %b is supported to decode error registers. 462 * Its usage is: 463 * 464 * kprintf("reg=%b\n", regval, "<base><arg>*"); 465 * 466 * where <base> is the output base expressed as a control character, e.g. 467 * \10 gives octal; \20 gives hex. Each arg is a sequence of characters, 468 * the first of which gives the bit number to be inspected (origin 1), and 469 * the next characters (up to a control character, i.e. a character <= 32), 470 * give the name of the register. Thus: 471 * 472 * kvcprintf("reg=%b\n", 3, "\10\2BITTWO\1BITONE\n"); 473 * 474 * would produce output: 475 * 476 * reg=3<BITTWO,BITONE> 477 * 478 * XXX: %D -- Hexdump, takes pointer and separator string: 479 * ("%6D", ptr, ":") -> XX:XX:XX:XX:XX:XX 480 * ("%*D", len, ptr, " " -> XX XX XX XX ... 481 */ 482 int 483 kvcprintf(char const *fmt, void (*func)(int, void*), void *arg, int radix, __va_list ap) 484 { 485 #define PCHAR(c) {int cc=(c); if (func) (*func)(cc,arg); else *d++ = cc; retval++; } 486 char nbuf[MAXNBUF]; 487 char *d; 488 const char *p, *percent, *q; 489 u_char *up; 490 int ch, n; 491 uintmax_t num; 492 int base, tmp, width, ladjust, sharpflag, neg, sign, dot; 493 int jflag, lflag, qflag, tflag; 494 int dwidth, upper; 495 char padc; 496 int retval = 0, stop = 0; 497 498 num = 0; 499 if (!func) 500 d = (char *) arg; 501 else 502 d = NULL; 503 504 if (fmt == NULL) 505 fmt = "(fmt null)\n"; 506 507 if (radix < 2 || radix > 36) 508 radix = 10; 509 510 for (;;) { 511 padc = ' '; 512 width = 0; 513 while ((ch = (u_char)*fmt++) != '%' || stop) { 514 if (ch == '\0') 515 return (retval); 516 PCHAR(ch); 517 } 518 percent = fmt - 1; 519 dot = dwidth = ladjust = neg = sharpflag = sign = upper = 0; 520 jflag = lflag = qflag = tflag = 0; 521 522 reswitch: 523 switch (ch = (u_char)*fmt++) { 524 case '.': 525 dot = 1; 526 goto reswitch; 527 case '#': 528 sharpflag = 1; 529 goto reswitch; 530 case '+': 531 sign = 1; 532 goto reswitch; 533 case '-': 534 ladjust = 1; 535 goto reswitch; 536 case '%': 537 PCHAR(ch); 538 break; 539 case '*': 540 if (!dot) { 541 width = __va_arg(ap, int); 542 if (width < 0) { 543 ladjust = !ladjust; 544 width = -width; 545 } 546 } else { 547 dwidth = __va_arg(ap, int); 548 } 549 goto reswitch; 550 case '0': 551 if (!dot) { 552 padc = '0'; 553 goto reswitch; 554 } 555 case '1': case '2': case '3': case '4': 556 case '5': case '6': case '7': case '8': case '9': 557 for (n = 0;; ++fmt) { 558 n = n * 10 + ch - '0'; 559 ch = *fmt; 560 if (ch < '0' || ch > '9') 561 break; 562 } 563 if (dot) 564 dwidth = n; 565 else 566 width = n; 567 goto reswitch; 568 case 'b': 569 num = (u_int)__va_arg(ap, int); 570 p = __va_arg(ap, char *); 571 for (q = ksprintn(nbuf, num, *p++, NULL, 0); *q;) 572 PCHAR(*q--); 573 574 if (num == 0) 575 break; 576 577 for (tmp = 0; *p;) { 578 n = *p++; 579 if (num & (1 << (n - 1))) { 580 PCHAR(tmp ? ',' : '<'); 581 for (; (n = *p) > ' '; ++p) 582 PCHAR(n); 583 tmp = 1; 584 } else 585 for (; *p > ' '; ++p) 586 continue; 587 } 588 if (tmp) 589 PCHAR('>'); 590 break; 591 case 'c': 592 PCHAR(__va_arg(ap, int)); 593 break; 594 case 'D': 595 up = __va_arg(ap, u_char *); 596 p = __va_arg(ap, char *); 597 if (!width) 598 width = 16; 599 while(width--) { 600 PCHAR(hex2ascii(*up >> 4)); 601 PCHAR(hex2ascii(*up & 0x0f)); 602 up++; 603 if (width) 604 for (q=p;*q;q++) 605 PCHAR(*q); 606 } 607 break; 608 case 'd': 609 case 'i': 610 base = 10; 611 sign = 1; 612 goto handle_sign; 613 case 'j': 614 jflag = 1; 615 goto reswitch; 616 case 'l': 617 if (lflag) { 618 lflag = 0; 619 qflag = 1; 620 } else 621 lflag = 1; 622 goto reswitch; 623 case 'n': 624 if (jflag) 625 *(__va_arg(ap, intmax_t *)) = retval; 626 else if (lflag) 627 *(__va_arg(ap, long *)) = retval; 628 else if (qflag) 629 *(__va_arg(ap, quad_t *)) = retval; 630 else 631 *(__va_arg(ap, int *)) = retval; 632 break; 633 case 'o': 634 base = 8; 635 goto handle_nosign; 636 case 'p': 637 base = 16; 638 sharpflag = (width == 0); 639 sign = 0; 640 num = (uintptr_t)__va_arg(ap, void *); 641 goto number; 642 case 'q': 643 qflag = 1; 644 goto reswitch; 645 case 'r': 646 base = radix; 647 if (sign) 648 goto handle_sign; 649 goto handle_nosign; 650 case 's': 651 p = __va_arg(ap, char *); 652 if (p == NULL) 653 p = "(null)"; 654 if (!dot) 655 n = strlen (p); 656 else 657 for (n = 0; n < dwidth && p[n]; n++) 658 continue; 659 660 width -= n; 661 662 if (!ladjust && width > 0) 663 while (width--) 664 PCHAR(padc); 665 while (n--) 666 PCHAR(*p++); 667 if (ladjust && width > 0) 668 while (width--) 669 PCHAR(padc); 670 break; 671 case 't': 672 tflag = 1; 673 goto reswitch; 674 case 'u': 675 base = 10; 676 goto handle_nosign; 677 case 'X': 678 upper = 1; 679 /* FALLTHROUGH */ 680 case 'x': 681 base = 16; 682 goto handle_nosign; 683 case 'z': 684 base = 16; 685 sign = 1; 686 goto handle_sign; 687 handle_nosign: 688 sign = 0; 689 if (jflag) 690 num = __va_arg(ap, uintmax_t); 691 else if (lflag) 692 num = __va_arg(ap, u_long); 693 else if (qflag) 694 num = __va_arg(ap, u_quad_t); 695 else if (tflag) 696 num = __va_arg(ap, ptrdiff_t); 697 else 698 num = __va_arg(ap, u_int); 699 goto number; 700 handle_sign: 701 if (jflag) 702 num = __va_arg(ap, intmax_t); 703 else if (lflag) 704 num = __va_arg(ap, long); 705 else if (qflag) 706 num = __va_arg(ap, quad_t); 707 else if (tflag) 708 num = __va_arg(ap, ptrdiff_t); 709 else 710 num = __va_arg(ap, int); 711 number: 712 if (sign && (intmax_t)num < 0) { 713 neg = 1; 714 num = -(intmax_t)num; 715 } 716 p = ksprintn(nbuf, num, base, &tmp, upper); 717 if (sharpflag && num != 0) { 718 if (base == 8) 719 tmp++; 720 else if (base == 16) 721 tmp += 2; 722 } 723 if (neg) 724 tmp++; 725 726 if (!ladjust && padc != '0' && width && 727 (width -= tmp) > 0) { 728 while (width--) 729 PCHAR(padc); 730 } 731 if (neg) 732 PCHAR('-'); 733 if (sharpflag && num != 0) { 734 if (base == 8) { 735 PCHAR('0'); 736 } else if (base == 16) { 737 PCHAR('0'); 738 PCHAR('x'); 739 } 740 } 741 if (!ladjust && width && (width -= tmp) > 0) 742 while (width--) 743 PCHAR(padc); 744 745 while (*p) 746 PCHAR(*p--); 747 748 if (ladjust && width && (width -= tmp) > 0) 749 while (width--) 750 PCHAR(padc); 751 752 break; 753 default: 754 while (percent < fmt) 755 PCHAR(*percent++); 756 /* 757 * Since we ignore an formatting argument it is no 758 * longer safe to obey the remaining formatting 759 * arguments as the arguments will no longer match 760 * the format specs. 761 */ 762 stop = 1; 763 break; 764 } 765 } 766 #undef PCHAR 767 } 768 769 /* 770 * Put character in log buffer with a particular priority. 771 * 772 * MPSAFE 773 */ 774 static void 775 msglogchar(int c, int pri) 776 { 777 static int lastpri = -1; 778 static int dangling; 779 char nbuf[MAXNBUF]; 780 char *p; 781 782 if (!msgbufmapped) 783 return; 784 if (c == '\0' || c == '\r') 785 return; 786 if (pri != -1 && pri != lastpri) { 787 if (dangling) { 788 msgaddchar('\n', NULL); 789 dangling = 0; 790 } 791 msgaddchar('<', NULL); 792 for (p = ksprintn(nbuf, (uintmax_t)pri, 10, NULL, 0); *p;) 793 msgaddchar(*p--, NULL); 794 msgaddchar('>', NULL); 795 lastpri = pri; 796 } 797 msgaddchar(c, NULL); 798 if (c == '\n') { 799 dangling = 0; 800 lastpri = -1; 801 } else { 802 dangling = 1; 803 } 804 } 805 806 /* 807 * Put char in log buffer. Make sure nothing blows up beyond repair if 808 * we have an MP race. 809 * 810 * MPSAFE. 811 */ 812 static void 813 msgaddchar(int c, void *dummy) 814 { 815 struct msgbuf *mbp; 816 int rindex; 817 int windex; 818 819 if (!msgbufmapped) 820 return; 821 mbp = msgbufp; 822 windex = mbp->msg_bufx; 823 mbp->msg_ptr[windex] = c; 824 if (++windex >= mbp->msg_size) 825 windex = 0; 826 rindex = mbp->msg_bufr; 827 if (windex == rindex) { 828 rindex += 32; 829 if (rindex >= mbp->msg_size) 830 rindex -= mbp->msg_size; 831 mbp->msg_bufr = rindex; 832 } 833 mbp->msg_bufx = windex; 834 } 835 836 static void 837 msgbufcopy(struct msgbuf *oldp) 838 { 839 int pos; 840 841 pos = oldp->msg_bufr; 842 while (pos != oldp->msg_bufx) { 843 msglogchar(oldp->msg_ptr[pos], -1); 844 if (++pos >= oldp->msg_size) 845 pos = 0; 846 } 847 } 848 849 void 850 msgbufinit(void *ptr, size_t size) 851 { 852 char *cp; 853 static struct msgbuf *oldp = NULL; 854 855 size -= sizeof(*msgbufp); 856 cp = (char *)ptr; 857 msgbufp = (struct msgbuf *) (cp + size); 858 if (msgbufp->msg_magic != MSG_MAGIC || msgbufp->msg_size != size || 859 msgbufp->msg_bufx >= size || msgbufp->msg_bufr >= size) { 860 bzero(cp, size); 861 bzero(msgbufp, sizeof(*msgbufp)); 862 msgbufp->msg_magic = MSG_MAGIC; 863 msgbufp->msg_size = (char *)msgbufp - cp; 864 } 865 msgbufp->msg_ptr = cp; 866 if (msgbufmapped && oldp != msgbufp) 867 msgbufcopy(oldp); 868 msgbufmapped = 1; 869 oldp = msgbufp; 870 } 871 872 /* Sysctls for accessing/clearing the msgbuf */ 873 874 static int 875 sysctl_kern_msgbuf(SYSCTL_HANDLER_ARGS) 876 { 877 struct ucred *cred; 878 int error; 879 880 /* 881 * Only wheel or root can access the message log. 882 */ 883 if (unprivileged_read_msgbuf == 0) { 884 KKASSERT(req->td->td_proc); 885 cred = req->td->td_proc->p_ucred; 886 887 if ((cred->cr_prison || groupmember(0, cred) == 0) && 888 suser(req->td) != 0 889 ) { 890 return (EPERM); 891 } 892 } 893 894 /* 895 * Unwind the buffer, so that it's linear (possibly starting with 896 * some initial nulls). 897 */ 898 error = sysctl_handle_opaque(oidp, msgbufp->msg_ptr + msgbufp->msg_bufx, 899 msgbufp->msg_size - msgbufp->msg_bufx, req); 900 if (error) 901 return (error); 902 if (msgbufp->msg_bufx > 0) { 903 error = sysctl_handle_opaque(oidp, msgbufp->msg_ptr, 904 msgbufp->msg_bufx, req); 905 } 906 return (error); 907 } 908 909 SYSCTL_PROC(_kern, OID_AUTO, msgbuf, CTLTYPE_STRING | CTLFLAG_RD, 910 0, 0, sysctl_kern_msgbuf, "A", "Contents of kernel message buffer"); 911 912 static int msgbuf_clear; 913 914 static int 915 sysctl_kern_msgbuf_clear(SYSCTL_HANDLER_ARGS) 916 { 917 int error; 918 error = sysctl_handle_int(oidp, oidp->oid_arg1, oidp->oid_arg2, req); 919 if (!error && req->newptr) { 920 /* Clear the buffer and reset write pointer */ 921 bzero(msgbufp->msg_ptr, msgbufp->msg_size); 922 msgbufp->msg_bufr = msgbufp->msg_bufx = 0; 923 msgbuf_clear = 0; 924 } 925 return (error); 926 } 927 928 SYSCTL_PROC(_kern, OID_AUTO, msgbuf_clear, 929 CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_SECURE, &msgbuf_clear, 0, 930 sysctl_kern_msgbuf_clear, "I", "Clear kernel message buffer"); 931 932 #ifdef DDB 933 934 DB_SHOW_COMMAND(msgbuf, db_show_msgbuf) 935 { 936 int i, j; 937 938 if (!msgbufmapped) { 939 db_printf("msgbuf not mapped yet\n"); 940 return; 941 } 942 db_printf("msgbufp = %p\n", msgbufp); 943 db_printf("magic = %x, size = %d, r= %d, w = %d, ptr = %p\n", 944 msgbufp->msg_magic, msgbufp->msg_size, msgbufp->msg_bufr, 945 msgbufp->msg_bufx, msgbufp->msg_ptr); 946 for (i = 0; i < msgbufp->msg_size; i++) { 947 j = (i + msgbufp->msg_bufr) % msgbufp->msg_size; 948 db_printf("%c", msgbufp->msg_ptr[j]); 949 } 950 db_printf("\n"); 951 } 952 953 #endif /* DDB */ 954