sys/kern/subr_prf.c

   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 1.16 2006/12/24 00:47:54 swildner Exp $
  41  */
  42
  43 #include <sys/param.h>
  44 #include <sys/systm.h>
  45 #include <sys/kernel.h>
  46 #include <sys/msgbuf.h>
  47 #include <sys/malloc.h>
  48 #include <sys/proc.h>
  49 #include <sys/tty.h>
  50 #include <sys/tprintf.h>
  51 #include <sys/syslog.h>
  52 #include <sys/cons.h>
  53 #include <sys/uio.h>
  54 #include <sys/sysctl.h>
  55 #include <sys/lock.h>
  56
  57 /*
  58  * Note that stdarg.h and the ANSI style va_start macro is used for both
  59  * ANSI and traditional C compilers.  We use the __ machine version to stay
  60  * within the kernel header file set.
  61  */
  62 #include <machine/stdarg.h>
  63
  64 #define TOCONS  0x01
  65 #define TOTTY   0x02
  66 #define TOLOG   0x04
  67
  68 /* Max number conversion buffer length: a u_quad_t in base 2, plus NUL byte. */
  69 #define MAXNBUF (sizeof(quad_t) * NBBY + 1)
  70
  71 struct putchar_arg {
  72         int     flags;
  73         int     pri;
  74         struct  tty *tty;
  75 };
  76
  77 struct snprintf_arg {
  78         char    *str;
  79         size_t  remain;
  80 };
  81
  82 extern  int log_open;
  83
  84 struct  tty *constty;                   /* pointer to console "window" tty */
  85
  86 static void (*v_putc)(int) = cnputc;    /* routine to putc on virtual console */
  87 static void  msglogchar(int c, int pri);
  88 static void  msgaddchar(int c, void *dummy);
  89 static void  kputchar (int ch, void *arg);
  90 static char *ksprintn (char *nbuf, u_long num, int base, int *len);
  91 static char *ksprintqn (char *nbuf, u_quad_t num, int base, int *len);
  92 static void  snprintf_func (int ch, void *arg);
  93
  94 static int consintr = 1;                /* Ok to handle console interrupts? */
  95 static int msgbufmapped;                /* Set when safe to use msgbuf */
  96 int msgbuftrigger;
  97
  98 static int      log_console_output = 1;
  99 TUNABLE_INT("kern.log_console_output", &log_console_output);
 100 SYSCTL_INT(_kern, OID_AUTO, log_console_output, CTLFLAG_RW,
 101     &log_console_output, 0, "");
 102
 103 static int unprivileged_read_msgbuf = 1;
 104 SYSCTL_INT(_kern, OID_AUTO, unprivileged_read_msgbuf, CTLFLAG_RW,
 105     &unprivileged_read_msgbuf, 0,
 106     "Unprivileged processes may read the kernel message buffer");
 107
 108 /*
 109  * Warn that a system table is full.
 110  */
 111 void
 112 tablefull(const char *tab)
 113 {
 114
 115         log(LOG_ERR, "%s: table is full\n", tab);
 116 }
 117
 118 /*
 119  * Uprintf prints to the controlling terminal for the current process.
 120  * It may block if the tty queue is overfull.  No message is printed if
 121  * the queue does not clear in a reasonable time.
 122  */
 123 int
 124 uprintf(const char *fmt, ...)
 125 {
 126         struct proc *p = curproc;
 127         __va_list ap;
 128         struct putchar_arg pca;
 129         int retval = 0;
 130
 131         if (p && p->p_flag & P_CONTROLT &&
 132             p->p_session->s_ttyvp) {
 133                 __va_start(ap, fmt);
 134                 pca.tty = p->p_session->s_ttyp;
 135                 pca.flags = TOTTY;
 136
 137                 retval = kvcprintf(fmt, kputchar, &pca, 10, ap);
 138                 __va_end(ap);
 139         }
 140         return retval;
 141 }
 142
 143 tpr_t
 144 tprintf_open(struct proc *p)
 145 {
 146
 147         if ((p->p_flag & P_CONTROLT) && p->p_session->s_ttyvp) {
 148                 sess_hold(p->p_session);
 149                 return ((tpr_t) p->p_session);
 150         }
 151         return ((tpr_t) NULL);
 152 }
 153
 154 void
 155 tprintf_close(tpr_t sess)
 156 {
 157         if (sess)
 158                 sess_rele((struct session *) sess);
 159 }
 160
 161 /*
 162  * tprintf prints on the controlling terminal associated
 163  * with the given session.
 164  */
 165 int
 166 tprintf(tpr_t tpr, const char *fmt, ...)
 167 {
 168         struct session *sess = (struct session *)tpr;
 169         struct tty *tp = NULL;
 170         int flags = TOLOG;
 171         __va_list ap;
 172         struct putchar_arg pca;
 173         int retval;
 174
 175         if (sess && sess->s_ttyvp && ttycheckoutq(sess->s_ttyp, 0)) {
 176                 flags |= TOTTY;
 177                 tp = sess->s_ttyp;
 178         }
 179         __va_start(ap, fmt);
 180         pca.tty = tp;
 181         pca.flags = flags;
 182         pca.pri = LOG_INFO;
 183         retval = kvcprintf(fmt, kputchar, &pca, 10, ap);
 184         __va_end(ap);
 185         msgbuftrigger = 1;
 186         return retval;
 187 }
 188
 189 /*
 190  * Ttyprintf displays a message on a tty; it should be used only by
 191  * the tty driver, or anything that knows the underlying tty will not
 192  * be revoke(2)'d away.  Other callers should use tprintf.
 193  */
 194 int
 195 ttyprintf(struct tty *tp, const char *fmt, ...)
 196 {
 197         __va_list ap;
 198         struct putchar_arg pca;
 199         int retval;
 200
 201         __va_start(ap, fmt);
 202         pca.tty = tp;
 203         pca.flags = TOTTY;
 204         retval = kvcprintf(fmt, kputchar, &pca, 10, ap);
 205         __va_end(ap);
 206         return retval;
 207 }
 208
 209 /*
 210  * Log writes to the log buffer, and guarantees not to sleep (so can be
 211  * called by interrupt routines).  If there is no process reading the
 212  * log yet, it writes to the console also.
 213  */
 214 int
 215 log(int level, const char *fmt, ...)
 216 {
 217         __va_list ap;
 218         int retval;
 219         struct putchar_arg pca;
 220
 221         pca.tty = NULL;
 222         pca.pri = level;
 223         pca.flags = log_open ? TOLOG : TOCONS;
 224
 225         __va_start(ap, fmt);
 226         retval = kvcprintf(fmt, kputchar, &pca, 10, ap);
 227         __va_end(ap);
 228
 229         msgbuftrigger = 1;
 230         return (retval);
 231 }
 232
 233 int
 234 addlog(const char *fmt, ...)
 235 {
 236         __va_list ap;
 237         int retval;
 238         struct putchar_arg pca;
 239
 240         pca.tty = NULL;
 241         pca.pri = -1;
 242         pca.flags = log_open ? TOLOG : TOCONS;
 243
 244         __va_start(ap, fmt);
 245         retval = kvcprintf(fmt, kputchar, &pca, 10, ap);
 246         __va_end(ap);
 247
 248         msgbuftrigger = 1;
 249         return (retval);
 250 }
 251
 252 #define CONSCHUNK 128
 253
 254 void
 255 log_console(struct uio *uio)
 256 {
 257         int c, i, error, iovlen, nl;
 258         struct uio muio;
 259         struct iovec *miov = NULL;
 260         char *consbuffer;
 261         int pri;
 262
 263         if (!log_console_output)
 264                 return;
 265
 266         pri = LOG_INFO | LOG_CONSOLE;
 267         muio = *uio;
 268         iovlen = uio->uio_iovcnt * sizeof (struct iovec);
 269         MALLOC(miov, struct iovec *, iovlen, M_TEMP, M_WAITOK);
 270         MALLOC(consbuffer, char *, CONSCHUNK, M_TEMP, M_WAITOK);
 271         bcopy((caddr_t)muio.uio_iov, (caddr_t)miov, iovlen);
 272         muio.uio_iov = miov;
 273         uio = &muio;
 274
 275         nl = 0;
 276         while (uio->uio_resid > 0) {
 277                 c = imin(uio->uio_resid, CONSCHUNK);
 278                 error = uiomove(consbuffer, c, uio);
 279                 if (error != 0)
 280                         return;
 281                 for (i = 0; i < c; i++) {
 282                         msglogchar(consbuffer[i], pri);
 283                         if (consbuffer[i] == '\n')
 284                                 nl = 1;
 285                         else
 286                                 nl = 0;
 287                 }
 288         }
 289         if (!nl)
 290                 msglogchar('\n', pri);
 291         msgbuftrigger = 1;
 292         FREE(miov, M_TEMP);
 293         FREE(consbuffer, M_TEMP);
 294         return;
 295 }
 296
 297 /*
 298  * Output to the console.
 299  *
 300  * NOT YET ENTIRELY MPSAFE
 301  */
 302 int
 303 kprintf(const char *fmt, ...)
 304 {
 305         __va_list ap;
 306         int savintr;
 307         struct putchar_arg pca;
 308         int retval;
 309
 310         savintr = consintr;             /* disable interrupts */
 311         consintr = 0;
 312         __va_start(ap, fmt);
 313         pca.tty = NULL;
 314         pca.flags = TOCONS | TOLOG;
 315         pca.pri = -1;
 316         cons_lock();
 317         retval = kvcprintf(fmt, kputchar, &pca, 10, ap);
 318         cons_unlock();
 319         __va_end(ap);
 320         if (!panicstr)
 321                 msgbuftrigger = 1;
 322         consintr = savintr;             /* reenable interrupts */
 323         return retval;
 324 }
 325
 326 int
 327 kvprintf(const char *fmt, __va_list ap)
 328 {
 329         int savintr;
 330         struct putchar_arg pca;
 331         int retval;
 332
 333         savintr = consintr;             /* disable interrupts */
 334         consintr = 0;
 335         pca.tty = NULL;
 336         pca.flags = TOCONS | TOLOG;
 337         pca.pri = -1;
 338         cons_lock();
 339         retval = kvcprintf(fmt, kputchar, &pca, 10, ap);
 340         cons_unlock();
 341         if (!panicstr)
 342                 msgbuftrigger = 1;
 343         consintr = savintr;             /* reenable interrupts */
 344         return retval;
 345 }
 346
 347 /*
 348  * Print a character on console or users terminal.  If destination is
 349  * the console then the last bunch of characters are saved in msgbuf for
 350  * inspection later.
 351  *
 352  * NOT YET ENTIRELY MPSAFE, EVEN WHEN LOGGING JUST TO THE SYSCONSOLE.
 353  */
 354 static void
 355 kputchar(int c, void *arg)
 356 {
 357         struct putchar_arg *ap = (struct putchar_arg*) arg;
 358         int flags = ap->flags;
 359         struct tty *tp = ap->tty;
 360         if (panicstr)
 361                 constty = NULL;
 362         if ((flags & TOCONS) && tp == NULL && constty) {
 363                 tp = constty;
 364                 flags |= TOTTY;
 365         }
 366         if ((flags & TOTTY) && tp && tputchar(c, tp) < 0 &&
 367             (flags & TOCONS) && tp == constty)
 368                 constty = NULL;
 369         if ((flags & TOLOG))
 370                 msglogchar(c, ap->pri);
 371         if ((flags & TOCONS) && constty == NULL && c != '\0')
 372                 (*v_putc)(c);
 373 }
 374
 375 /*
 376  * Scaled down version of sprintf(3).
 377  */
 378 int
 379 ksprintf(char *buf, const char *cfmt, ...)
 380 {
 381         int retval;
 382         __va_list ap;
 383
 384         __va_start(ap, cfmt);
 385         retval = kvcprintf(cfmt, NULL, (void *)buf, 10, ap);
 386         buf[retval] = '\0';
 387         __va_end(ap);
 388         return retval;
 389 }
 390
 391 /*
 392  * Scaled down version of vsprintf(3).
 393  */
 394 int
 395 kvsprintf(char *buf, const char *cfmt, __va_list ap)
 396 {
 397         int retval;
 398
 399         retval = kvcprintf(cfmt, NULL, (void *)buf, 10, ap);
 400         buf[retval] = '\0';
 401         return retval;
 402 }
 403
 404 /*
 405  * Scaled down version of snprintf(3).
 406  */
 407 int
 408 ksnprintf(char *str, size_t size, const char *format, ...)
 409 {
 410         int retval;
 411         __va_list ap;
 412
 413         __va_start(ap, format);
 414         retval = kvsnprintf(str, size, format, ap);
 415         __va_end(ap);
 416         return(retval);
 417 }
 418
 419 /*
 420  * Scaled down version of vsnprintf(3).
 421  */
 422 int
 423 kvsnprintf(char *str, size_t size, const char *format, __va_list ap)
 424 {
 425         struct snprintf_arg info;
 426         int retval;
 427
 428         info.str = str;
 429         info.remain = size;
 430         retval = kvcprintf(format, snprintf_func, &info, 10, ap);
 431         if (info.remain >= 1)
 432                 *info.str++ = '\0';
 433         return retval;
 434 }
 435
 436 static void
 437 snprintf_func(int ch, void *arg)
 438 {
 439         struct snprintf_arg *const info = arg;
 440
 441         if (info->remain >= 2) {
 442                 *info->str++ = ch;
 443                 info->remain--;
 444         }
 445 }
 446
 447 /*
 448  * Put a NUL-terminated ASCII number (base <= 36) in a buffer in reverse
 449  * order; return an optional length and a pointer to the last character
 450  * written in the buffer (i.e., the first character of the string).
 451  * The buffer pointed to by `nbuf' must have length >= MAXNBUF.
 452  */
 453 static char *
 454 ksprintn(char *nbuf, u_long ul, int base, int *lenp)
 455 {
 456         char *p;
 457
 458         p = nbuf;
 459         *p = '\0';
 460         do {
 461                 *++p = hex2ascii(ul % base);
 462         } while (ul /= base);
 463         if (lenp)
 464                 *lenp = p - nbuf;
 465         return (p);
 466 }
 467 /* ksprintn, but for a quad_t. */
 468 static char *
 469 ksprintqn(char *nbuf, u_quad_t uq, int base, int *lenp)
 470 {
 471         char *p;
 472
 473         p = nbuf;
 474         *p = '\0';
 475         do {
 476                 *++p = hex2ascii(uq % base);
 477         } while (uq /= base);
 478         if (lenp)
 479                 *lenp = p - nbuf;
 480         return (p);
 481 }
 482
 483 /*
 484  * Scaled down version of printf(3).
 485  *
 486  * Two additional formats:
 487  *
 488  * The format %b is supported to decode error registers.
 489  * Its usage is:
 490  *
 491  *      kprintf("reg=%b\n", regval, "<base><arg>*");
 492  *
 493  * where <base> is the output base expressed as a control character, e.g.
 494  * \10 gives octal; \20 gives hex.  Each arg is a sequence of characters,
 495  * the first of which gives the bit number to be inspected (origin 1), and
 496  * the next characters (up to a control character, i.e. a character <= 32),
 497  * give the name of the register.  Thus:
 498  *
 499  *      kvcprintf("reg=%b\n", 3, "\10\2BITTWO\1BITONE\n");
 500  *
 501  * would produce output:
 502  *
 503  *      reg=3<BITTWO,BITONE>
 504  *
 505  * XXX:  %D  -- Hexdump, takes pointer and separator string:
 506  *              ("%6D", ptr, ":")   -> XX:XX:XX:XX:XX:XX
 507  *              ("%*D", len, ptr, " " -> XX XX XX XX ...
 508  */
 509 int
 510 kvcprintf(char const *fmt, void (*func)(int, void*), void *arg, int radix, __va_list ap)
 511 {
 512 #define PCHAR(c) {int cc=(c); if (func) (*func)(cc,arg); else *d++ = cc; retval++; }
 513         char nbuf[MAXNBUF];
 514         char *p, *q, *d;
 515         u_char *up;
 516         int ch, n;
 517         u_long ul;
 518         u_quad_t uq;
 519         int base, lflag, qflag, tmp, width, ladjust, sharpflag, neg, sign, dot;
 520         int dwidth;
 521         char padc;
 522         int retval = 0;
 523
 524         ul = 0;
 525         uq = 0;
 526         if (!func)
 527                 d = (char *) arg;
 528         else
 529                 d = NULL;
 530
 531         if (fmt == NULL)
 532                 fmt = "(fmt null)\n";
 533
 534         if (radix < 2 || radix > 36)
 535                 radix = 10;
 536
 537         for (;;) {
 538                 padc = ' ';
 539                 width = 0;
 540                 while ((ch = (u_char)*fmt++) != '%') {
 541                         if (ch == '\0')
 542                                 return retval;
 543                         PCHAR(ch);
 544                 }
 545                 qflag = 0; lflag = 0; ladjust = 0; sharpflag = 0; neg = 0;
 546                 sign = 0; dot = 0; dwidth = 0;
 547 reswitch:       switch (ch = (u_char)*fmt++) {
 548                 case '.':
 549                         dot = 1;
 550                         goto reswitch;
 551                 case '#':
 552                         sharpflag = 1;
 553                         goto reswitch;
 554                 case '+':
 555                         sign = 1;
 556                         goto reswitch;
 557                 case '-':
 558                         ladjust = 1;
 559                         goto reswitch;
 560                 case '%':
 561                         PCHAR(ch);
 562                         break;
 563                 case '*':
 564                         if (!dot) {
 565                                 width = __va_arg(ap, int);
 566                                 if (width < 0) {
 567                                         ladjust = !ladjust;
 568                                         width = -width;
 569                                 }
 570                         } else {
 571                                 dwidth = __va_arg(ap, int);
 572                         }
 573                         goto reswitch;
 574                 case '0':
 575                         if (!dot) {
 576                                 padc = '0';
 577                                 goto reswitch;
 578                         }
 579                 case '1': case '2': case '3': case '4':
 580                 case '5': case '6': case '7': case '8': case '9':
 581                                 for (n = 0;; ++fmt) {
 582                                         n = n * 10 + ch - '0';
 583                                         ch = *fmt;
 584                                         if (ch < '0' || ch > '9')
 585                                                 break;
 586                                 }
 587                         if (dot)
 588                                 dwidth = n;
 589                         else
 590                                 width = n;
 591                         goto reswitch;
 592                 case 'b':
 593                         ul = __va_arg(ap, int);
 594                         p = __va_arg(ap, char *);
 595                         for (q = ksprintn(nbuf, ul, *p++, NULL); *q;)
 596                                 PCHAR(*q--);
 597
 598                         if (!ul)
 599                                 break;
 600
 601                         for (tmp = 0; *p;) {
 602                                 n = *p++;
 603                                 if (ul & (1 << (n - 1))) {
 604                                         PCHAR(tmp ? ',' : '<');
 605                                         for (; (n = *p) > ' '; ++p)
 606                                                 PCHAR(n);
 607                                         tmp = 1;
 608                                 } else
 609                                         for (; *p > ' '; ++p)
 610                                                 continue;
 611                         }
 612                         if (tmp)
 613                                 PCHAR('>');
 614                         break;
 615                 case 'c':
 616                         PCHAR(__va_arg(ap, int));
 617                         break;
 618                 case 'D':
 619                         up = __va_arg(ap, u_char *);
 620                         p = __va_arg(ap, char *);
 621                         if (!width)
 622                                 width = 16;
 623                         while(width--) {
 624                                 PCHAR(hex2ascii(*up >> 4));
 625                                 PCHAR(hex2ascii(*up & 0x0f));
 626                                 up++;
 627                                 if (width)
 628                                         for (q=p;*q;q++)
 629                                                 PCHAR(*q);
 630                         }
 631                         break;
 632                 case 'd':
 633                         if (qflag)
 634                                 uq = __va_arg(ap, quad_t);
 635                         else if (lflag)
 636                                 ul = __va_arg(ap, long);
 637                         else
 638                                 ul = __va_arg(ap, int);
 639                         sign = 1;
 640                         base = 10;
 641                         goto number;
 642                 case 'l':
 643                         if (lflag) {
 644                                 lflag = 0;
 645                                 qflag = 1;
 646                         } else
 647                                 lflag = 1;
 648                         goto reswitch;
 649                 case 'o':
 650                         if (qflag)
 651                                 uq = __va_arg(ap, u_quad_t);
 652                         else if (lflag)
 653                                 ul = __va_arg(ap, u_long);
 654                         else
 655                                 ul = __va_arg(ap, u_int);
 656                         base = 8;
 657                         goto nosign;
 658                 case 'p':
 659                         ul = (uintptr_t)__va_arg(ap, void *);
 660                         base = 16;
 661                         sharpflag = (width == 0);
 662                         goto nosign;
 663                 case 'q':
 664                         qflag = 1;
 665                         goto reswitch;
 666                 case 'n':
 667                 case 'r':
 668                         if (qflag)
 669                                 uq = __va_arg(ap, u_quad_t);
 670                         else if (lflag)
 671                                 ul = __va_arg(ap, u_long);
 672                         else
 673                                 ul = sign ?
 674                                     (u_long)__va_arg(ap, int) : __va_arg(ap, u_int);
 675                         base = radix;
 676                         goto number;
 677                 case 's':
 678                         p = __va_arg(ap, char *);
 679                         if (p == NULL)
 680                                 p = "(null)";
 681                         if (!dot)
 682                                 n = strlen (p);
 683                         else
 684                                 for (n = 0; n < dwidth && p[n]; n++)
 685                                         continue;
 686
 687                         width -= n;
 688
 689                         if (!ladjust && width > 0)
 690                                 while (width--)
 691                                         PCHAR(padc);
 692                         while (n--)
 693                                 PCHAR(*p++);
 694                         if (ladjust && width > 0)
 695                                 while (width--)
 696                                         PCHAR(padc);
 697                         break;
 698                 case 'u':
 699                         if (qflag)
 700                                 uq = __va_arg(ap, u_quad_t);
 701                         else if (lflag)
 702                                 ul = __va_arg(ap, u_long);
 703                         else
 704                                 ul = __va_arg(ap, u_int);
 705                         base = 10;
 706                         goto nosign;
 707                 case 'x':
 708                 case 'X':
 709                         if (qflag)
 710                                 uq = __va_arg(ap, u_quad_t);
 711                         else if (lflag)
 712                                 ul = __va_arg(ap, u_long);
 713                         else
 714                                 ul = __va_arg(ap, u_int);
 715                         base = 16;
 716                         goto nosign;
 717                 case 'z':
 718                         if (qflag)
 719                                 uq = __va_arg(ap, u_quad_t);
 720                         else if (lflag)
 721                                 ul = __va_arg(ap, u_long);
 722                         else
 723                                 ul = sign ?
 724                                     (u_long)__va_arg(ap, int) : __va_arg(ap, u_int);
 725                         base = 16;
 726                         goto number;
 727 nosign:                 sign = 0;
 728 number:
 729                         if (qflag) {
 730                                 if (sign && (quad_t)uq < 0) {
 731                                         neg = 1;
 732                                         uq = -(quad_t)uq;
 733                                 }
 734                                 p = ksprintqn(nbuf, uq, base, &tmp);
 735                         } else {
 736                                 if (sign && (long)ul < 0) {
 737                                         neg = 1;
 738                                         ul = -(long)ul;
 739                                 }
 740                                 p = ksprintn(nbuf, ul, base, &tmp);
 741                         }
 742                         if (sharpflag && (qflag ? uq != 0 : ul != 0)) {
 743                                 if (base == 8)
 744                                         tmp++;
 745                                 else if (base == 16)
 746                                         tmp += 2;
 747                         }
 748                         if (neg)
 749                                 tmp++;
 750
 751                         if (!ladjust && width && (width -= tmp) > 0)
 752                                 while (width--)
 753                                         PCHAR(padc);
 754                         if (neg)
 755                                 PCHAR('-');
 756                         if (sharpflag && (qflag ? uq != 0 : ul != 0)) {
 757                                 if (base == 8) {
 758                                         PCHAR('0');
 759                                 } else if (base == 16) {
 760                                         PCHAR('0');
 761                                         PCHAR('x');
 762                                 }
 763                         }
 764
 765                         while (*p)
 766                                 PCHAR(*p--);
 767
 768                         if (ladjust && width && (width -= tmp) > 0)
 769                                 while (width--)
 770                                         PCHAR(padc);
 771
 772                         break;
 773                 default:
 774                         PCHAR('%');
 775                         if (lflag)
 776                                 PCHAR('l');
 777                         PCHAR(ch);
 778                         break;
 779                 }
 780         }
 781 #undef PCHAR
 782 }
 783
 784 /*
 785  * Put character in log buffer with a particular priority.
 786  *
 787  * MPSAFE
 788  */
 789 static void
 790 msglogchar(int c, int pri)
 791 {
 792         static int lastpri = -1;
 793         static int dangling;
 794         char nbuf[MAXNBUF];
 795         char *p;
 796
 797         if (!msgbufmapped)
 798                 return;
 799         if (c == '\0' || c == '\r')
 800                 return;
 801         if (pri != -1 && pri != lastpri) {
 802                 if (dangling) {
 803                         msgaddchar('\n', NULL);
 804                         dangling = 0;
 805                 }
 806                 msgaddchar('<', NULL);
 807                 for (p = ksprintn(nbuf, (u_long)pri, 10, NULL); *p;)
 808                         msgaddchar(*p--, NULL);
 809                 msgaddchar('>', NULL);
 810                 lastpri = pri;
 811         }
 812         msgaddchar(c, NULL);
 813         if (c == '\n') {
 814                 dangling = 0;
 815                 lastpri = -1;
 816         } else {
 817                 dangling = 1;
 818         }
 819 }
 820
 821 /*
 822  * Put char in log buffer.   Make sure nothing blows up beyond repair if
 823  * we have an MP race.
 824  *
 825  * MPSAFE.
 826  */
 827 static void
 828 msgaddchar(int c, void *dummy)
 829 {
 830         struct msgbuf *mbp;
 831         int rindex;
 832         int windex;
 833
 834         if (!msgbufmapped)
 835                 return;
 836         mbp = msgbufp;
 837         windex = mbp->msg_bufx;
 838         mbp->msg_ptr[windex] = c;
 839         if (++windex >= mbp->msg_size)
 840                 windex = 0;
 841         rindex = mbp->msg_bufr;
 842         if (windex == rindex) {
 843                 rindex += 32;
 844                 if (rindex >= mbp->msg_size)
 845                         rindex -= mbp->msg_size;
 846                 mbp->msg_bufr = rindex;
 847         }
 848         mbp->msg_bufx = windex;
 849 }
 850
 851 static void
 852 msgbufcopy(struct msgbuf *oldp)
 853 {
 854         int pos;
 855
 856         pos = oldp->msg_bufr;
 857         while (pos != oldp->msg_bufx) {
 858                 msglogchar(oldp->msg_ptr[pos], -1);
 859                 if (++pos >= oldp->msg_size)
 860                         pos = 0;
 861         }
 862 }
 863
 864 void
 865 msgbufinit(void *ptr, size_t size)
 866 {
 867         char *cp;
 868         static struct msgbuf *oldp = NULL;
 869
 870         size -= sizeof(*msgbufp);
 871         cp = (char *)ptr;
 872         msgbufp = (struct msgbuf *) (cp + size);
 873         if (msgbufp->msg_magic != MSG_MAGIC || msgbufp->msg_size != size ||
 874             msgbufp->msg_bufx >= size || msgbufp->msg_bufr >= size) {
 875                 bzero(cp, size);
 876                 bzero(msgbufp, sizeof(*msgbufp));
 877                 msgbufp->msg_magic = MSG_MAGIC;
 878                 msgbufp->msg_size = (char *)msgbufp - cp;
 879         }
 880         msgbufp->msg_ptr = cp;
 881         if (msgbufmapped && oldp != msgbufp)
 882                 msgbufcopy(oldp);
 883         msgbufmapped = 1;
 884         oldp = msgbufp;
 885 }
 886
 887 /* Sysctls for accessing/clearing the msgbuf */
 888
 889 static int
 890 sysctl_kern_msgbuf(SYSCTL_HANDLER_ARGS)
 891 {
 892         struct ucred *cred;
 893         int error;
 894
 895         /*
 896          * Only wheel or root can access the message log.
 897          */
 898         if (unprivileged_read_msgbuf == 0) {
 899                 KKASSERT(req->td->td_proc);
 900                 cred = req->td->td_proc->p_ucred;
 901
 902                 if ((cred->cr_prison || groupmember(0, cred) == 0) &&
 903                     suser(req->td) != 0
 904                 ) {
 905                         return (EPERM);
 906                 }
 907         }
 908
 909         /*
 910          * Unwind the buffer, so that it's linear (possibly starting with
 911          * some initial nulls).
 912          */
 913         error = sysctl_handle_opaque(oidp, msgbufp->msg_ptr + msgbufp->msg_bufx,
 914             msgbufp->msg_size - msgbufp->msg_bufx, req);
 915         if (error)
 916                 return (error);
 917         if (msgbufp->msg_bufx > 0) {
 918                 error = sysctl_handle_opaque(oidp, msgbufp->msg_ptr,
 919                     msgbufp->msg_bufx, req);
 920         }
 921         return (error);
 922 }
 923
 924 SYSCTL_PROC(_kern, OID_AUTO, msgbuf, CTLTYPE_STRING | CTLFLAG_RD,
 925     0, 0, sysctl_kern_msgbuf, "A", "Contents of kernel message buffer");
 926
 927 static int msgbuf_clear;
 928
 929 static int
 930 sysctl_kern_msgbuf_clear(SYSCTL_HANDLER_ARGS)
 931 {
 932         int error;
 933         error = sysctl_handle_int(oidp, oidp->oid_arg1, oidp->oid_arg2, req);
 934         if (!error && req->newptr) {
 935                 /* Clear the buffer and reset write pointer */
 936                 bzero(msgbufp->msg_ptr, msgbufp->msg_size);
 937                 msgbufp->msg_bufr = msgbufp->msg_bufx = 0;
 938                 msgbuf_clear = 0;
 939         }
 940         return (error);
 941 }
 942
 943 SYSCTL_PROC(_kern, OID_AUTO, msgbuf_clear,
 944     CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_SECURE, &msgbuf_clear, 0,
 945     sysctl_kern_msgbuf_clear, "I", "Clear kernel message buffer");
 946
 947 #include "opt_ddb.h"
 948 #ifdef DDB
 949 #include <ddb/ddb.h>
 950
 951 DB_SHOW_COMMAND(msgbuf, db_show_msgbuf)
 952 {
 953         int i, j;
 954
 955         if (!msgbufmapped) {
 956                 db_printf("msgbuf not mapped yet\n");
 957                 return;
 958         }
 959         db_printf("msgbufp = %p\n", msgbufp);
 960         db_printf("magic = %x, size = %d, r= %d, w = %d, ptr = %p\n",
 961             msgbufp->msg_magic, msgbufp->msg_size, msgbufp->msg_bufr,
 962             msgbufp->msg_bufx, msgbufp->msg_ptr);
 963         for (i = 0; i < msgbufp->msg_size; i++) {
 964                 j = (i + msgbufp->msg_bufr) % msgbufp->msg_size;
 965                 db_printf("%c", msgbufp->msg_ptr[j]);
 966         }
 967         db_printf("\n");
 968 }
 969
 970 #endif /* DDB */