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 1.21 2008/07/17 23:56:23 dillon 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/priv.h>
  52 #include <sys/tty.h>
  53 #include <sys/tprintf.h>
  54 #include <sys/stdint.h>
  55 #include <sys/syslog.h>
  56 #include <sys/cons.h>
  57 #include <sys/uio.h>
  58 #include <sys/sysctl.h>
  59 #include <sys/lock.h>
  60 #include <sys/ctype.h>
  61
  62 #ifdef DDB
  63 #include <ddb/ddb.h>
  64 #endif
  65
  66 /*
  67  * Note that stdarg.h and the ANSI style va_start macro is used for both
  68  * ANSI and traditional C compilers.  We use the __ machine version to stay
  69  * within the kernel header file set.
  70  */
  71 #include <machine/stdarg.h>
  72
  73 #define TOCONS  0x01
  74 #define TOTTY   0x02
  75 #define TOLOG   0x04
  76
  77 /* Max number conversion buffer length: a u_quad_t in base 2, plus NUL byte. */
  78 #define MAXNBUF (sizeof(intmax_t) * NBBY + 1)
  79
  80 struct putchar_arg {
  81         int     flags;
  82         int     pri;
  83         struct  tty *tty;
  84 };
  85
  86 struct snprintf_arg {
  87         char    *str;
  88         size_t  remain;
  89 };
  90
  91 extern  int log_open;
  92
  93 struct  tty *constty;                   /* pointer to console "window" tty */
  94
  95 static void (*v_putc)(int) = cnputc;    /* routine to putc on virtual console */
  96 static void  msglogchar(int c, int pri);
  97 static void  msgaddchar(int c, void *dummy);
  98 static void  kputchar (int ch, void *arg);
  99 static char *ksprintn (char *nbuf, uintmax_t num, int base, int *lenp,
 100                        int upper);
 101 static void  snprintf_func (int ch, void *arg);
 102
 103 static int consintr = 1;                /* Ok to handle console interrupts? */
 104 static int msgbufmapped;                /* Set when safe to use msgbuf */
 105 int msgbuftrigger;
 106
 107 static int      log_console_output = 1;
 108 TUNABLE_INT("kern.log_console_output", &log_console_output);
 109 SYSCTL_INT(_kern, OID_AUTO, log_console_output, CTLFLAG_RW,
 110     &log_console_output, 0, "");
 111
 112 static int unprivileged_read_msgbuf = 1;
 113 SYSCTL_INT(_security, OID_AUTO, unprivileged_read_msgbuf, CTLFLAG_RW,
 114     &unprivileged_read_msgbuf, 0,
 115     "Unprivileged processes may read the kernel message buffer");
 116
 117 /*
 118  * Warn that a system table is full.
 119  */
 120 void
 121 tablefull(const char *tab)
 122 {
 123
 124         log(LOG_ERR, "%s: table is full\n", tab);
 125 }
 126
 127 /*
 128  * Uprintf prints to the controlling terminal for the current process.
 129  */
 130 int
 131 uprintf(const char *fmt, ...)
 132 {
 133         struct proc *p = curproc;
 134         __va_list ap;
 135         struct putchar_arg pca;
 136         int retval = 0;
 137
 138         if (p && p->p_flag & P_CONTROLT &&
 139             p->p_session->s_ttyvp) {
 140                 __va_start(ap, fmt);
 141                 pca.tty = p->p_session->s_ttyp;
 142                 pca.flags = TOTTY;
 143
 144                 retval = kvcprintf(fmt, kputchar, &pca, 10, ap);
 145                 __va_end(ap);
 146         }
 147         return (retval);
 148 }
 149
 150 tpr_t
 151 tprintf_open(struct proc *p)
 152 {
 153
 154         if ((p->p_flag & P_CONTROLT) && p->p_session->s_ttyvp) {
 155                 sess_hold(p->p_session);
 156                 return ((tpr_t) p->p_session);
 157         }
 158         return ((tpr_t) NULL);
 159 }
 160
 161 void
 162 tprintf_close(tpr_t sess)
 163 {
 164         if (sess)
 165                 sess_rele((struct session *) sess);
 166 }
 167
 168 /*
 169  * tprintf prints on the controlling terminal associated
 170  * with the given session.
 171  */
 172 int
 173 tprintf(tpr_t tpr, const char *fmt, ...)
 174 {
 175         struct session *sess = (struct session *)tpr;
 176         struct tty *tp = NULL;
 177         int flags = TOLOG;
 178         __va_list ap;
 179         struct putchar_arg pca;
 180         int retval;
 181
 182         if (sess && sess->s_ttyvp && ttycheckoutq(sess->s_ttyp, 0)) {
 183                 flags |= TOTTY;
 184                 tp = sess->s_ttyp;
 185         }
 186         __va_start(ap, fmt);
 187         pca.tty = tp;
 188         pca.flags = flags;
 189         pca.pri = LOG_INFO;
 190         retval = kvcprintf(fmt, kputchar, &pca, 10, ap);
 191         __va_end(ap);
 192         msgbuftrigger = 1;
 193         return (retval);
 194 }
 195
 196 /*
 197  * Ttyprintf displays a message on a tty; it should be used only by
 198  * the tty driver, or anything that knows the underlying tty will not
 199  * be revoke(2)'d away.  Other callers should use tprintf.
 200  */
 201 int
 202 ttyprintf(struct tty *tp, const char *fmt, ...)
 203 {
 204         __va_list ap;
 205         struct putchar_arg pca;
 206         int retval;
 207
 208         __va_start(ap, fmt);
 209         pca.tty = tp;
 210         pca.flags = TOTTY;
 211         retval = kvcprintf(fmt, kputchar, &pca, 10, ap);
 212         __va_end(ap);
 213         return (retval);
 214 }
 215
 216 /*
 217  * Log writes to the log buffer, and guarantees not to sleep (so can be
 218  * called by interrupt routines).  If there is no process reading the
 219  * log yet, it writes to the console also.
 220  */
 221 int
 222 log(int level, const char *fmt, ...)
 223 {
 224         __va_list ap;
 225         int retval;
 226         struct putchar_arg pca;
 227
 228         pca.tty = NULL;
 229         pca.pri = level;
 230         pca.flags = log_open ? TOLOG : TOCONS;
 231
 232         __va_start(ap, fmt);
 233         retval = kvcprintf(fmt, kputchar, &pca, 10, ap);
 234         __va_end(ap);
 235
 236         msgbuftrigger = 1;
 237         return (retval);
 238 }
 239
 240 #define CONSCHUNK 128
 241
 242 void
 243 log_console(struct uio *uio)
 244 {
 245         int c, i, error, iovlen, nl;
 246         struct uio muio;
 247         struct iovec *miov = NULL;
 248         char *consbuffer;
 249         int pri;
 250
 251         if (!log_console_output)
 252                 return;
 253
 254         pri = LOG_INFO | LOG_CONSOLE;
 255         muio = *uio;
 256         iovlen = uio->uio_iovcnt * sizeof (struct iovec);
 257         MALLOC(miov, struct iovec *, iovlen, M_TEMP, M_WAITOK);
 258         MALLOC(consbuffer, char *, CONSCHUNK, M_TEMP, M_WAITOK);
 259         bcopy((caddr_t)muio.uio_iov, (caddr_t)miov, iovlen);
 260         muio.uio_iov = miov;
 261         uio = &muio;
 262
 263         nl = 0;
 264         while (uio->uio_resid > 0) {
 265                 c = imin(uio->uio_resid, CONSCHUNK);
 266                 error = uiomove(consbuffer, c, uio);
 267                 if (error != 0)
 268                         break;
 269                 for (i = 0; i < c; i++) {
 270                         msglogchar(consbuffer[i], pri);
 271                         if (consbuffer[i] == '\n')
 272                                 nl = 1;
 273                         else
 274                                 nl = 0;
 275                 }
 276         }
 277         if (!nl)
 278                 msglogchar('\n', pri);
 279         msgbuftrigger = 1;
 280         FREE(miov, M_TEMP);
 281         FREE(consbuffer, M_TEMP);
 282         return;
 283 }
 284
 285 /*
 286  * Output to the console.
 287  *
 288  * NOT YET ENTIRELY MPSAFE
 289  */
 290 int
 291 kprintf(const char *fmt, ...)
 292 {
 293         __va_list ap;
 294         int savintr;
 295         struct putchar_arg pca;
 296         int retval;
 297
 298         savintr = consintr;             /* disable interrupts */
 299         consintr = 0;
 300         __va_start(ap, fmt);
 301         pca.tty = NULL;
 302         pca.flags = TOCONS | TOLOG;
 303         pca.pri = -1;
 304         cons_lock();
 305         retval = kvcprintf(fmt, kputchar, &pca, 10, ap);
 306         cons_unlock();
 307         __va_end(ap);
 308         if (!panicstr)
 309                 msgbuftrigger = 1;
 310         consintr = savintr;             /* reenable interrupts */
 311         return (retval);
 312 }
 313
 314 int
 315 kvprintf(const char *fmt, __va_list ap)
 316 {
 317         int savintr;
 318         struct putchar_arg pca;
 319         int retval;
 320
 321         savintr = consintr;             /* disable interrupts */
 322         consintr = 0;
 323         pca.tty = NULL;
 324         pca.flags = TOCONS | TOLOG;
 325         pca.pri = -1;
 326         cons_lock();
 327         retval = kvcprintf(fmt, kputchar, &pca, 10, ap);
 328         cons_unlock();
 329         if (!panicstr)
 330                 msgbuftrigger = 1;
 331         consintr = savintr;             /* reenable interrupts */
 332         return (retval);
 333 }
 334
 335 /*
 336  * Limited rate kprintf.  The passed rate structure must be initialized
 337  * with the desired reporting frequency.  A frequency of 0 will result in
 338  * no output.
 339  *
 340  * count may be initialized to a negative number to allow an initial
 341  * burst.
 342  */
 343 void
 344 krateprintf(struct krate *rate, const char *fmt, ...)
 345 {
 346         __va_list ap;
 347
 348         if (rate->ticks != (int)time_second) {
 349                 rate->ticks = (int)time_second;
 350                 if (rate->count > 0)
 351                         rate->count = 0;
 352         }
 353         if (rate->count < rate->freq) {
 354                 ++rate->count;
 355                 __va_start(ap, fmt);
 356                 kvprintf(fmt, ap);
 357                 __va_end(ap);
 358         }
 359 }
 360
 361 /*
 362  * Print a character on console or users terminal.  If destination is
 363  * the console then the last bunch of characters are saved in msgbuf for
 364  * inspection later.
 365  *
 366  * NOT YET ENTIRELY MPSAFE, EVEN WHEN LOGGING JUST TO THE SYSCONSOLE.
 367  */
 368 static void
 369 kputchar(int c, void *arg)
 370 {
 371         struct putchar_arg *ap = (struct putchar_arg*) arg;
 372         int flags = ap->flags;
 373         struct tty *tp = ap->tty;
 374         if (panicstr)
 375                 constty = NULL;
 376         if ((flags & TOCONS) && tp == NULL && constty) {
 377                 tp = constty;
 378                 flags |= TOTTY;
 379         }
 380         if ((flags & TOTTY) && tp && tputchar(c, tp) < 0 &&
 381             (flags & TOCONS) && tp == constty)
 382                 constty = NULL;
 383         if ((flags & TOLOG))
 384                 msglogchar(c, ap->pri);
 385         if ((flags & TOCONS) && constty == NULL && c != '\0')
 386                 (*v_putc)(c);
 387 }
 388
 389 /*
 390  * Scaled down version of sprintf(3).
 391  */
 392 int
 393 ksprintf(char *buf, const char *cfmt, ...)
 394 {
 395         int retval;
 396         __va_list ap;
 397
 398         __va_start(ap, cfmt);
 399         retval = kvcprintf(cfmt, NULL, (void *)buf, 10, ap);
 400         buf[retval] = '\0';
 401         __va_end(ap);
 402         return (retval);
 403 }
 404
 405 /*
 406  * Scaled down version of vsprintf(3).
 407  */
 408 int
 409 kvsprintf(char *buf, const char *cfmt, __va_list ap)
 410 {
 411         int retval;
 412
 413         retval = kvcprintf(cfmt, NULL, (void *)buf, 10, ap);
 414         buf[retval] = '\0';
 415         return (retval);
 416 }
 417
 418 /*
 419  * Scaled down version of snprintf(3).
 420  */
 421 int
 422 ksnprintf(char *str, size_t size, const char *format, ...)
 423 {
 424         int retval;
 425         __va_list ap;
 426
 427         __va_start(ap, format);
 428         retval = kvsnprintf(str, size, format, ap);
 429         __va_end(ap);
 430         return(retval);
 431 }
 432
 433 /*
 434  * Scaled down version of vsnprintf(3).
 435  */
 436 int
 437 kvsnprintf(char *str, size_t size, const char *format, __va_list ap)
 438 {
 439         struct snprintf_arg info;
 440         int retval;
 441
 442         info.str = str;
 443         info.remain = size;
 444         retval = kvcprintf(format, snprintf_func, &info, 10, ap);
 445         if (info.remain >= 1)
 446                 *info.str++ = '\0';
 447         return (retval);
 448 }
 449
 450 static void
 451 snprintf_func(int ch, void *arg)
 452 {
 453         struct snprintf_arg *const info = arg;
 454
 455         if (info->remain >= 2) {
 456                 *info->str++ = ch;
 457                 info->remain--;
 458         }
 459 }
 460
 461 /*
 462  * Put a NUL-terminated ASCII number (base <= 36) in a buffer in reverse
 463  * order; return an optional length and a pointer to the last character
 464  * written in the buffer (i.e., the first character of the string).
 465  * The buffer pointed to by `nbuf' must have length >= MAXNBUF.
 466  */
 467 static char *
 468 ksprintn(char *nbuf, uintmax_t num, int base, int *lenp, int upper)
 469 {
 470         char *p, c;
 471
 472         p = nbuf;
 473         *p = '\0';
 474         do {
 475                 c = hex2ascii(num % base);
 476                 *++p = upper ? toupper(c) : c;
 477         } while (num /= 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 *d;
 515         const char *p, *percent, *q;
 516         u_char *up;
 517         int ch, n;
 518         uintmax_t num;
 519         int base, tmp, width, ladjust, sharpflag, neg, sign, dot;
 520         int jflag, lflag, qflag, tflag;
 521         int dwidth, upper;
 522         char padc;
 523         int retval = 0, stop = 0;
 524
 525         num = 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++) != '%' || stop) {
 541                         if (ch == '\0')
 542                                 return (retval);
 543                         PCHAR(ch);
 544                 }
 545                 percent = fmt - 1;
 546                 dot = dwidth = ladjust = neg = sharpflag = sign = upper = 0;
 547                 jflag = lflag = qflag = tflag = 0;
 548
 549 reswitch:
 550                 switch (ch = (u_char)*fmt++) {
 551                 case '.':
 552                         dot = 1;
 553                         goto reswitch;
 554                 case '#':
 555                         sharpflag = 1;
 556                         goto reswitch;
 557                 case '+':
 558                         sign = 1;
 559                         goto reswitch;
 560                 case '-':
 561                         ladjust = 1;
 562                         goto reswitch;
 563                 case '%':
 564                         PCHAR(ch);
 565                         break;
 566                 case '*':
 567                         if (!dot) {
 568                                 width = __va_arg(ap, int);
 569                                 if (width < 0) {
 570                                         ladjust = !ladjust;
 571                                         width = -width;
 572                                 }
 573                         } else {
 574                                 dwidth = __va_arg(ap, int);
 575                         }
 576                         goto reswitch;
 577                 case '0':
 578                         if (!dot) {
 579                                 padc = '0';
 580                                 goto reswitch;
 581                         }
 582                 case '1': case '2': case '3': case '4':
 583                 case '5': case '6': case '7': case '8': case '9':
 584                                 for (n = 0;; ++fmt) {
 585                                         n = n * 10 + ch - '0';
 586                                         ch = *fmt;
 587                                         if (ch < '0' || ch > '9')
 588                                                 break;
 589                                 }
 590                         if (dot)
 591                                 dwidth = n;
 592                         else
 593                                 width = n;
 594                         goto reswitch;
 595                 case 'b':
 596                         num = (u_int)__va_arg(ap, int);
 597                         p = __va_arg(ap, char *);
 598                         for (q = ksprintn(nbuf, num, *p++, NULL, 0); *q;)
 599                                 PCHAR(*q--);
 600
 601                         if (num == 0)
 602                                 break;
 603
 604                         for (tmp = 0; *p;) {
 605                                 n = *p++;
 606                                 if (num & (1 << (n - 1))) {
 607                                         PCHAR(tmp ? ',' : '<');
 608                                         for (; (n = *p) > ' '; ++p)
 609                                                 PCHAR(n);
 610                                         tmp = 1;
 611                                 } else
 612                                         for (; *p > ' '; ++p)
 613                                                 continue;
 614                         }
 615                         if (tmp)
 616                                 PCHAR('>');
 617                         break;
 618                 case 'c':
 619                         PCHAR(__va_arg(ap, int));
 620                         break;
 621                 case 'D':
 622                         up = __va_arg(ap, u_char *);
 623                         p = __va_arg(ap, char *);
 624                         if (!width)
 625                                 width = 16;
 626                         while(width--) {
 627                                 PCHAR(hex2ascii(*up >> 4));
 628                                 PCHAR(hex2ascii(*up & 0x0f));
 629                                 up++;
 630                                 if (width)
 631                                         for (q=p;*q;q++)
 632                                                 PCHAR(*q);
 633                         }
 634                         break;
 635                 case 'd':
 636                 case 'i':
 637                         base = 10;
 638                         sign = 1;
 639                         goto handle_sign;
 640                 case 'j':
 641                         jflag = 1;
 642                         goto reswitch;
 643                 case 'l':
 644                         if (lflag) {
 645                                 lflag = 0;
 646                                 qflag = 1;
 647                         } else
 648                                 lflag = 1;
 649                         goto reswitch;
 650                 case 'n':
 651                         if (jflag)
 652                                 *(__va_arg(ap, intmax_t *)) = retval;
 653                         else if (lflag)
 654                                 *(__va_arg(ap, long *)) = retval;
 655                         else if (qflag)
 656                                 *(__va_arg(ap, quad_t *)) = retval;
 657                         else
 658                                 *(__va_arg(ap, int *)) = retval;
 659                         break;
 660                 case 'o':
 661                         base = 8;
 662                         goto handle_nosign;
 663                 case 'p':
 664                         base = 16;
 665                         sharpflag = (width == 0);
 666                         sign = 0;
 667                         num = (uintptr_t)__va_arg(ap, void *);
 668                         goto number;
 669                 case 'q':
 670                         qflag = 1;
 671                         goto reswitch;
 672                 case 'r':
 673                         base = radix;
 674                         if (sign)
 675                                 goto handle_sign;
 676                         goto handle_nosign;
 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 't':
 699                         tflag = 1;
 700                         goto reswitch;
 701                 case 'u':
 702                         base = 10;
 703                         goto handle_nosign;
 704                 case 'X':
 705                         upper = 1;
 706                         /* FALLTHROUGH */
 707                 case 'x':
 708                         base = 16;
 709                         goto handle_nosign;
 710                 case 'z':
 711                         base = 16;
 712                         sign = 1;
 713                         goto handle_sign;
 714 handle_nosign:
 715                         sign = 0;
 716                         if (jflag)
 717                                 num = __va_arg(ap, uintmax_t);
 718                         else if (lflag)
 719                                 num = __va_arg(ap, u_long);
 720                         else if (qflag)
 721                                 num = __va_arg(ap, u_quad_t);
 722                         else if (tflag)
 723                                 num = __va_arg(ap, ptrdiff_t);
 724                         else
 725                                 num = __va_arg(ap, u_int);
 726                         goto number;
 727 handle_sign:
 728                         if (jflag)
 729                                 num = __va_arg(ap, intmax_t);
 730                         else if (lflag)
 731                                 num = __va_arg(ap, long);
 732                         else if (qflag)
 733                                 num = __va_arg(ap, quad_t);
 734                         else if (tflag)
 735                                 num = __va_arg(ap, ptrdiff_t);
 736                         else
 737                                 num = __va_arg(ap, int);
 738 number:
 739                         if (sign && (intmax_t)num < 0) {
 740                                 neg = 1;
 741                                 num = -(intmax_t)num;
 742                         }
 743                         p = ksprintn(nbuf, num, base, &tmp, upper);
 744                         if (sharpflag && num != 0) {
 745                                 if (base == 8)
 746                                         tmp++;
 747                                 else if (base == 16)
 748                                         tmp += 2;
 749                         }
 750                         if (neg)
 751                                 tmp++;
 752
 753                         if (!ladjust && padc != '0' && width &&
 754                             (width -= tmp) > 0) {
 755                                 while (width--)
 756                                         PCHAR(padc);
 757                         }
 758                         if (neg)
 759                                 PCHAR('-');
 760                         if (sharpflag && num != 0) {
 761                                 if (base == 8) {
 762                                         PCHAR('0');
 763                                 } else if (base == 16) {
 764                                         PCHAR('0');
 765                                         PCHAR('x');
 766                                 }
 767                         }
 768                         if (!ladjust && width && (width -= tmp) > 0)
 769                                 while (width--)
 770                                         PCHAR(padc);
 771
 772                         while (*p)
 773                                 PCHAR(*p--);
 774
 775                         if (ladjust && width && (width -= tmp) > 0)
 776                                 while (width--)
 777                                         PCHAR(padc);
 778
 779                         break;
 780                 default:
 781                         while (percent < fmt)
 782                                 PCHAR(*percent++);
 783                         /*
 784                          * Since we ignore an formatting argument it is no
 785                          * longer safe to obey the remaining formatting
 786                          * arguments as the arguments will no longer match
 787                          * the format specs.
 788                          */
 789                         stop = 1;
 790                         break;
 791                 }
 792         }
 793 #undef PCHAR
 794 }
 795
 796 /*
 797  * Put character in log buffer with a particular priority.
 798  *
 799  * MPSAFE
 800  */
 801 static void
 802 msglogchar(int c, int pri)
 803 {
 804         static int lastpri = -1;
 805         static int dangling;
 806         char nbuf[MAXNBUF];
 807         char *p;
 808
 809         if (!msgbufmapped)
 810                 return;
 811         if (c == '\0' || c == '\r')
 812                 return;
 813         if (pri != -1 && pri != lastpri) {
 814                 if (dangling) {
 815                         msgaddchar('\n', NULL);
 816                         dangling = 0;
 817                 }
 818                 msgaddchar('<', NULL);
 819                 for (p = ksprintn(nbuf, (uintmax_t)pri, 10, NULL, 0); *p;)
 820                         msgaddchar(*p--, NULL);
 821                 msgaddchar('>', NULL);
 822                 lastpri = pri;
 823         }
 824         msgaddchar(c, NULL);
 825         if (c == '\n') {
 826                 dangling = 0;
 827                 lastpri = -1;
 828         } else {
 829                 dangling = 1;
 830         }
 831 }
 832
 833 /*
 834  * Put char in log buffer.   Make sure nothing blows up beyond repair if
 835  * we have an MP race.
 836  *
 837  * MPSAFE.
 838  */
 839 static void
 840 msgaddchar(int c, void *dummy)
 841 {
 842         struct msgbuf *mbp;
 843         int rindex;
 844         int windex;
 845
 846         if (!msgbufmapped)
 847                 return;
 848         mbp = msgbufp;
 849         windex = mbp->msg_bufx;
 850         mbp->msg_ptr[windex] = c;
 851         if (++windex >= mbp->msg_size)
 852                 windex = 0;
 853         rindex = mbp->msg_bufr;
 854         if (windex == rindex) {
 855                 rindex += 32;
 856                 if (rindex >= mbp->msg_size)
 857                         rindex -= mbp->msg_size;
 858                 mbp->msg_bufr = rindex;
 859         }
 860         mbp->msg_bufx = windex;
 861 }
 862
 863 static void
 864 msgbufcopy(struct msgbuf *oldp)
 865 {
 866         int pos;
 867
 868         pos = oldp->msg_bufr;
 869         while (pos != oldp->msg_bufx) {
 870                 msglogchar(oldp->msg_ptr[pos], -1);
 871                 if (++pos >= oldp->msg_size)
 872                         pos = 0;
 873         }
 874 }
 875
 876 void
 877 msgbufinit(void *ptr, size_t size)
 878 {
 879         char *cp;
 880         static struct msgbuf *oldp = NULL;
 881
 882         size -= sizeof(*msgbufp);
 883         cp = (char *)ptr;
 884         msgbufp = (struct msgbuf *) (cp + size);
 885         if (msgbufp->msg_magic != MSG_MAGIC || msgbufp->msg_size != size ||
 886             msgbufp->msg_bufx >= size || msgbufp->msg_bufr >= size) {
 887                 bzero(cp, size);
 888                 bzero(msgbufp, sizeof(*msgbufp));
 889                 msgbufp->msg_magic = MSG_MAGIC;
 890                 msgbufp->msg_size = (char *)msgbufp - cp;
 891         }
 892         msgbufp->msg_ptr = cp;
 893         if (msgbufmapped && oldp != msgbufp)
 894                 msgbufcopy(oldp);
 895         msgbufmapped = 1;
 896         oldp = msgbufp;
 897 }
 898
 899 /* Sysctls for accessing/clearing the msgbuf */
 900
 901 static int
 902 sysctl_kern_msgbuf(SYSCTL_HANDLER_ARGS)
 903 {
 904         struct ucred *cred;
 905         int error;
 906
 907         /*
 908          * Only wheel or root can access the message log.
 909          */
 910         if (unprivileged_read_msgbuf == 0) {
 911                 KKASSERT(req->td->td_proc);
 912                 cred = req->td->td_proc->p_ucred;
 913
 914                 if ((cred->cr_prison || groupmember(0, cred) == 0) &&
 915                     priv_check(req->td, PRIV_ROOT) != 0
 916                 ) {
 917                         return (EPERM);
 918                 }
 919         }
 920
 921         /*
 922          * Unwind the buffer, so that it's linear (possibly starting with
 923          * some initial nulls).
 924          */
 925         error = sysctl_handle_opaque(oidp, msgbufp->msg_ptr + msgbufp->msg_bufx,
 926             msgbufp->msg_size - msgbufp->msg_bufx, req);
 927         if (error)
 928                 return (error);
 929         if (msgbufp->msg_bufx > 0) {
 930                 error = sysctl_handle_opaque(oidp, msgbufp->msg_ptr,
 931                     msgbufp->msg_bufx, req);
 932         }
 933         return (error);
 934 }
 935
 936 SYSCTL_PROC(_kern, OID_AUTO, msgbuf, CTLTYPE_STRING | CTLFLAG_RD,
 937     0, 0, sysctl_kern_msgbuf, "A", "Contents of kernel message buffer");
 938
 939 static int msgbuf_clear;
 940
 941 static int
 942 sysctl_kern_msgbuf_clear(SYSCTL_HANDLER_ARGS)
 943 {
 944         int error;
 945         error = sysctl_handle_int(oidp, oidp->oid_arg1, oidp->oid_arg2, req);
 946         if (!error && req->newptr) {
 947                 /* Clear the buffer and reset write pointer */
 948                 bzero(msgbufp->msg_ptr, msgbufp->msg_size);
 949                 msgbufp->msg_bufr = msgbufp->msg_bufx = 0;
 950                 msgbuf_clear = 0;
 951         }
 952         return (error);
 953 }
 954
 955 SYSCTL_PROC(_kern, OID_AUTO, msgbuf_clear,
 956     CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_SECURE, &msgbuf_clear, 0,
 957     sysctl_kern_msgbuf_clear, "I", "Clear kernel message buffer");
 958
 959 #ifdef DDB
 960
 961 DB_SHOW_COMMAND(msgbuf, db_show_msgbuf)
 962 {
 963         int i, j;
 964
 965         if (!msgbufmapped) {
 966                 db_printf("msgbuf not mapped yet\n");
 967                 return;
 968         }
 969         db_printf("msgbufp = %p\n", msgbufp);
 970         db_printf("magic = %x, size = %d, r= %d, w = %d, ptr = %p\n",
 971             msgbufp->msg_magic, msgbufp->msg_size, msgbufp->msg_bufr,
 972             msgbufp->msg_bufx, msgbufp->msg_ptr);
 973         for (i = 0; i < msgbufp->msg_size; i++) {
 974                 j = (i + msgbufp->msg_bufr) % msgbufp->msg_size;
 975                 db_printf("%c", msgbufp->msg_ptr[j]);
 976         }
 977         db_printf("\n");
 978 }
 979
 980 #endif /* DDB */