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 1.17 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 */