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 1.18 2007/07/30 21:40:30 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/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  * Limited rate kprintf.  The passed rate structure must be initialized
 336  * with the desired reporting frequency.  A frequency of 0 will result in
 337  * no output.
 338  */
 339 void
 340 krateprintf(struct krate *rate, const char *fmt, ...)
 341 {
 342         __va_list ap;
 343
 344         if (rate->ticks != ticks) {
 345                 rate->ticks = ticks;
 346                 rate->count = 0;
 347         }
 348         if (rate->count < rate->freq) {
 349                 ++rate->count;
 350                 __va_start(ap, fmt);
 351                 kvprintf(fmt, ap);
 352                 __va_end(ap);
 353         }
 354 }
 355
 356 /*
 357  * Print a character on console or users terminal.  If destination is
 358  * the console then the last bunch of characters are saved in msgbuf for
 359  * inspection later.
 360  *
 361  * NOT YET ENTIRELY MPSAFE, EVEN WHEN LOGGING JUST TO THE SYSCONSOLE.
 362  */
 363 static void
 364 kputchar(int c, void *arg)
 365 {
 366         struct putchar_arg *ap = (struct putchar_arg*) arg;
 367         int flags = ap->flags;
 368         struct tty *tp = ap->tty;
 369         if (panicstr)
 370                 constty = NULL;
 371         if ((flags & TOCONS) && tp == NULL && constty) {
 372                 tp = constty;
 373                 flags |= TOTTY;
 374         }
 375         if ((flags & TOTTY) && tp && tputchar(c, tp) < 0 &&
 376             (flags & TOCONS) && tp == constty)
 377                 constty = NULL;
 378         if ((flags & TOLOG))
 379                 msglogchar(c, ap->pri);
 380         if ((flags & TOCONS) && constty == NULL && c != '\0')
 381                 (*v_putc)(c);
 382 }
 383
 384 /*
 385  * Scaled down version of sprintf(3).
 386  */
 387 int
 388 ksprintf(char *buf, const char *cfmt, ...)
 389 {
 390         int retval;
 391         __va_list ap;
 392
 393         __va_start(ap, cfmt);
 394         retval = kvcprintf(cfmt, NULL, (void *)buf, 10, ap);
 395         buf[retval] = '\0';
 396         __va_end(ap);
 397         return (retval);
 398 }
 399
 400 /*
 401  * Scaled down version of vsprintf(3).
 402  */
 403 int
 404 kvsprintf(char *buf, const char *cfmt, __va_list ap)
 405 {
 406         int retval;
 407
 408         retval = kvcprintf(cfmt, NULL, (void *)buf, 10, ap);
 409         buf[retval] = '\0';
 410         return (retval);
 411 }
 412
 413 /*
 414  * Scaled down version of snprintf(3).
 415  */
 416 int
 417 ksnprintf(char *str, size_t size, const char *format, ...)
 418 {
 419         int retval;
 420         __va_list ap;
 421
 422         __va_start(ap, format);
 423         retval = kvsnprintf(str, size, format, ap);
 424         __va_end(ap);
 425         return(retval);
 426 }
 427
 428 /*
 429  * Scaled down version of vsnprintf(3).
 430  */
 431 int
 432 kvsnprintf(char *str, size_t size, const char *format, __va_list ap)
 433 {
 434         struct snprintf_arg info;
 435         int retval;
 436
 437         info.str = str;
 438         info.remain = size;
 439         retval = kvcprintf(format, snprintf_func, &info, 10, ap);
 440         if (info.remain >= 1)
 441                 *info.str++ = '\0';
 442         return (retval);
 443 }
 444
 445 static void
 446 snprintf_func(int ch, void *arg)
 447 {
 448         struct snprintf_arg *const info = arg;
 449
 450         if (info->remain >= 2) {
 451                 *info->str++ = ch;
 452                 info->remain--;
 453         }
 454 }
 455
 456 /*
 457  * Put a NUL-terminated ASCII number (base <= 36) in a buffer in reverse
 458  * order; return an optional length and a pointer to the last character
 459  * written in the buffer (i.e., the first character of the string).
 460  * The buffer pointed to by `nbuf' must have length >= MAXNBUF.
 461  */
 462 static char *
 463 ksprintn(char *nbuf, uintmax_t num, int base, int *lenp, int upper)
 464 {
 465         char *p, c;
 466
 467         p = nbuf;
 468         *p = '\0';
 469         do {
 470                 c = hex2ascii(num % base);
 471                 *++p = upper ? toupper(c) : c;
 472         } while (num /= base);
 473         if (lenp)
 474                 *lenp = p - nbuf;
 475         return (p);
 476 }
 477
 478 /*
 479  * Scaled down version of printf(3).
 480  *
 481  * Two additional formats:
 482  *
 483  * The format %b is supported to decode error registers.
 484  * Its usage is:
 485  *
 486  *      kprintf("reg=%b\n", regval, "<base><arg>*");
 487  *
 488  * where <base> is the output base expressed as a control character, e.g.
 489  * \10 gives octal; \20 gives hex.  Each arg is a sequence of characters,
 490  * the first of which gives the bit number to be inspected (origin 1), and
 491  * the next characters (up to a control character, i.e. a character <= 32),
 492  * give the name of the register.  Thus:
 493  *
 494  *      kvcprintf("reg=%b\n", 3, "\10\2BITTWO\1BITONE\n");
 495  *
 496  * would produce output:
 497  *
 498  *      reg=3<BITTWO,BITONE>
 499  *
 500  * XXX:  %D  -- Hexdump, takes pointer and separator string:
 501  *              ("%6D", ptr, ":")   -> XX:XX:XX:XX:XX:XX
 502  *              ("%*D", len, ptr, " " -> XX XX XX XX ...
 503  */
 504 int
 505 kvcprintf(char const *fmt, void (*func)(int, void*), void *arg, int radix, __va_list ap)
 506 {
 507 #define PCHAR(c) {int cc=(c); if (func) (*func)(cc,arg); else *d++ = cc; retval++; }
 508         char nbuf[MAXNBUF];
 509         char *d;
 510         const char *p, *percent, *q;
 511         u_char *up;
 512         int ch, n;
 513         uintmax_t num;
 514         int base, tmp, width, ladjust, sharpflag, neg, sign, dot;
 515         int jflag, lflag, qflag, tflag;
 516         int dwidth, upper;
 517         char padc;
 518         int retval = 0, stop = 0;
 519
 520         num = 0;
 521         if (!func)
 522                 d = (char *) arg;
 523         else
 524                 d = NULL;
 525
 526         if (fmt == NULL)
 527                 fmt = "(fmt null)\n";
 528
 529         if (radix < 2 || radix > 36)
 530                 radix = 10;
 531
 532         for (;;) {
 533                 padc = ' ';
 534                 width = 0;
 535                 while ((ch = (u_char)*fmt++) != '%' || stop) {
 536                         if (ch == '\0')
 537                                 return (retval);
 538                         PCHAR(ch);
 539                 }
 540                 percent = fmt - 1;
 541                 dot = dwidth = ladjust = neg = sharpflag = sign = upper = 0;
 542                 jflag = lflag = qflag = tflag = 0;
 543
 544 reswitch:
 545                 switch (ch = (u_char)*fmt++) {
 546                 case '.':
 547                         dot = 1;
 548                         goto reswitch;
 549                 case '#':
 550                         sharpflag = 1;
 551                         goto reswitch;
 552                 case '+':
 553                         sign = 1;
 554                         goto reswitch;
 555                 case '-':
 556                         ladjust = 1;
 557                         goto reswitch;
 558                 case '%':
 559                         PCHAR(ch);
 560                         break;
 561                 case '*':
 562                         if (!dot) {
 563                                 width = __va_arg(ap, int);
 564                                 if (width < 0) {
 565                                         ladjust = !ladjust;
 566                                         width = -width;
 567                                 }
 568                         } else {
 569                                 dwidth = __va_arg(ap, int);
 570                         }
 571                         goto reswitch;
 572                 case '0':
 573                         if (!dot) {
 574                                 padc = '0';
 575                                 goto reswitch;
 576                         }
 577                 case '1': case '2': case '3': case '4':
 578                 case '5': case '6': case '7': case '8': case '9':
 579                                 for (n = 0;; ++fmt) {
 580                                         n = n * 10 + ch - '0';
 581                                         ch = *fmt;
 582                                         if (ch < '0' || ch > '9')
 583                                                 break;
 584                                 }
 585                         if (dot)
 586                                 dwidth = n;
 587                         else
 588                                 width = n;
 589                         goto reswitch;
 590                 case 'b':
 591                         num = (u_int)__va_arg(ap, int);
 592                         p = __va_arg(ap, char *);
 593                         for (q = ksprintn(nbuf, num, *p++, NULL, 0); *q;)
 594                                 PCHAR(*q--);
 595
 596                         if (num == 0)
 597                                 break;
 598
 599                         for (tmp = 0; *p;) {
 600                                 n = *p++;
 601                                 if (num & (1 << (n - 1))) {
 602                                         PCHAR(tmp ? ',' : '<');
 603                                         for (; (n = *p) > ' '; ++p)
 604                                                 PCHAR(n);
 605                                         tmp = 1;
 606                                 } else
 607                                         for (; *p > ' '; ++p)
 608                                                 continue;
 609                         }
 610                         if (tmp)
 611                                 PCHAR('>');
 612                         break;
 613                 case 'c':
 614                         PCHAR(__va_arg(ap, int));
 615                         break;
 616                 case 'D':
 617                         up = __va_arg(ap, u_char *);
 618                         p = __va_arg(ap, char *);
 619                         if (!width)
 620                                 width = 16;
 621                         while(width--) {
 622                                 PCHAR(hex2ascii(*up >> 4));
 623                                 PCHAR(hex2ascii(*up & 0x0f));
 624                                 up++;
 625                                 if (width)
 626                                         for (q=p;*q;q++)
 627                                                 PCHAR(*q);
 628                         }
 629                         break;
 630                 case 'd':
 631                 case 'i':
 632                         base = 10;
 633                         sign = 1;
 634                         goto handle_sign;
 635                 case 'j':
 636                         jflag = 1;
 637                         goto reswitch;
 638                 case 'l':
 639                         if (lflag) {
 640                                 lflag = 0;
 641                                 qflag = 1;
 642                         } else
 643                                 lflag = 1;
 644                         goto reswitch;
 645                 case 'n':
 646                         if (jflag)
 647                                 *(__va_arg(ap, intmax_t *)) = retval;
 648                         else if (lflag)
 649                                 *(__va_arg(ap, long *)) = retval;
 650                         else if (qflag)
 651                                 *(__va_arg(ap, quad_t *)) = retval;
 652                         else
 653                                 *(__va_arg(ap, int *)) = retval;
 654                         break;
 655                 case 'o':
 656                         base = 8;
 657                         goto handle_nosign;
 658                 case 'p':
 659                         base = 16;
 660                         sharpflag = (width == 0);
 661                         sign = 0;
 662                         num = (uintptr_t)__va_arg(ap, void *);
 663                         goto number;
 664                 case 'q':
 665                         qflag = 1;
 666                         goto reswitch;
 667                 case 'r':
 668                         base = radix;
 669                         if (sign)
 670                                 goto handle_sign;
 671                         goto handle_nosign;
 672                 case 's':
 673                         p = __va_arg(ap, char *);
 674                         if (p == NULL)
 675                                 p = "(null)";
 676                         if (!dot)
 677                                 n = strlen (p);
 678                         else
 679                                 for (n = 0; n < dwidth && p[n]; n++)
 680                                         continue;
 681
 682                         width -= n;
 683
 684                         if (!ladjust && width > 0)
 685                                 while (width--)
 686                                         PCHAR(padc);
 687                         while (n--)
 688                                 PCHAR(*p++);
 689                         if (ladjust && width > 0)
 690                                 while (width--)
 691                                         PCHAR(padc);
 692                         break;
 693                 case 't':
 694                         tflag = 1;
 695                         goto reswitch;
 696                 case 'u':
 697                         base = 10;
 698                         goto handle_nosign;
 699                 case 'X':
 700                         upper = 1;
 701                         /* FALLTHROUGH */
 702                 case 'x':
 703                         base = 16;
 704                         goto handle_nosign;
 705                 case 'z':
 706                         base = 16;
 707                         sign = 1;
 708                         goto handle_sign;
 709 handle_nosign:
 710                         sign = 0;
 711                         if (jflag)
 712                                 num = __va_arg(ap, uintmax_t);
 713                         else if (lflag)
 714                                 num = __va_arg(ap, u_long);
 715                         else if (qflag)
 716                                 num = __va_arg(ap, u_quad_t);
 717                         else if (tflag)
 718                                 num = __va_arg(ap, ptrdiff_t);
 719                         else
 720                                 num = __va_arg(ap, u_int);
 721                         goto number;
 722 handle_sign:
 723                         if (jflag)
 724                                 num = __va_arg(ap, intmax_t);
 725                         else if (lflag)
 726                                 num = __va_arg(ap, long);
 727                         else if (qflag)
 728                                 num = __va_arg(ap, quad_t);
 729                         else if (tflag)
 730                                 num = __va_arg(ap, ptrdiff_t);
 731                         else
 732                                 num = __va_arg(ap, int);
 733 number:
 734                         if (sign && (intmax_t)num < 0) {
 735                                 neg = 1;
 736                                 num = -(intmax_t)num;
 737                         }
 738                         p = ksprintn(nbuf, num, base, &tmp, upper);
 739                         if (sharpflag && num != 0) {
 740                                 if (base == 8)
 741                                         tmp++;
 742                                 else if (base == 16)
 743                                         tmp += 2;
 744                         }
 745                         if (neg)
 746                                 tmp++;
 747
 748                         if (!ladjust && padc != '0' && width &&
 749                             (width -= tmp) > 0) {
 750                                 while (width--)
 751                                         PCHAR(padc);
 752                         }
 753                         if (neg)
 754                                 PCHAR('-');
 755                         if (sharpflag && num != 0) {
 756                                 if (base == 8) {
 757                                         PCHAR('0');
 758                                 } else if (base == 16) {
 759                                         PCHAR('0');
 760                                         PCHAR('x');
 761                                 }
 762                         }
 763                         if (!ladjust && width && (width -= tmp) > 0)
 764                                 while (width--)
 765                                         PCHAR(padc);
 766
 767                         while (*p)
 768                                 PCHAR(*p--);
 769
 770                         if (ladjust && width && (width -= tmp) > 0)
 771                                 while (width--)
 772                                         PCHAR(padc);
 773
 774                         break;
 775                 default:
 776                         while (percent < fmt)
 777                                 PCHAR(*percent++);
 778                         /*
 779                          * Since we ignore an formatting argument it is no
 780                          * longer safe to obey the remaining formatting
 781                          * arguments as the arguments will no longer match
 782                          * the format specs.
 783                          */
 784                         stop = 1;
 785                         break;
 786                 }
 787         }
 788 #undef PCHAR
 789 }
 790
 791 /*
 792  * Put character in log buffer with a particular priority.
 793  *
 794  * MPSAFE
 795  */
 796 static void
 797 msglogchar(int c, int pri)
 798 {
 799         static int lastpri = -1;
 800         static int dangling;
 801         char nbuf[MAXNBUF];
 802         char *p;
 803
 804         if (!msgbufmapped)
 805                 return;
 806         if (c == '\0' || c == '\r')
 807                 return;
 808         if (pri != -1 && pri != lastpri) {
 809                 if (dangling) {
 810                         msgaddchar('\n', NULL);
 811                         dangling = 0;
 812                 }
 813                 msgaddchar('<', NULL);
 814                 for (p = ksprintn(nbuf, (uintmax_t)pri, 10, NULL, 0); *p;)
 815                         msgaddchar(*p--, NULL);
 816                 msgaddchar('>', NULL);
 817                 lastpri = pri;
 818         }
 819         msgaddchar(c, NULL);
 820         if (c == '\n') {
 821                 dangling = 0;
 822                 lastpri = -1;
 823         } else {
 824                 dangling = 1;
 825         }
 826 }
 827
 828 /*
 829  * Put char in log buffer.   Make sure nothing blows up beyond repair if
 830  * we have an MP race.
 831  *
 832  * MPSAFE.
 833  */
 834 static void
 835 msgaddchar(int c, void *dummy)
 836 {
 837         struct msgbuf *mbp;
 838         int rindex;
 839         int windex;
 840
 841         if (!msgbufmapped)
 842                 return;
 843         mbp = msgbufp;
 844         windex = mbp->msg_bufx;
 845         mbp->msg_ptr[windex] = c;
 846         if (++windex >= mbp->msg_size)
 847                 windex = 0;
 848         rindex = mbp->msg_bufr;
 849         if (windex == rindex) {
 850                 rindex += 32;
 851                 if (rindex >= mbp->msg_size)
 852                         rindex -= mbp->msg_size;
 853                 mbp->msg_bufr = rindex;
 854         }
 855         mbp->msg_bufx = windex;
 856 }
 857
 858 static void
 859 msgbufcopy(struct msgbuf *oldp)
 860 {
 861         int pos;
 862
 863         pos = oldp->msg_bufr;
 864         while (pos != oldp->msg_bufx) {
 865                 msglogchar(oldp->msg_ptr[pos], -1);
 866                 if (++pos >= oldp->msg_size)
 867                         pos = 0;
 868         }
 869 }
 870
 871 void
 872 msgbufinit(void *ptr, size_t size)
 873 {
 874         char *cp;
 875         static struct msgbuf *oldp = NULL;
 876
 877         size -= sizeof(*msgbufp);
 878         cp = (char *)ptr;
 879         msgbufp = (struct msgbuf *) (cp + size);
 880         if (msgbufp->msg_magic != MSG_MAGIC || msgbufp->msg_size != size ||
 881             msgbufp->msg_bufx >= size || msgbufp->msg_bufr >= size) {
 882                 bzero(cp, size);
 883                 bzero(msgbufp, sizeof(*msgbufp));
 884                 msgbufp->msg_magic = MSG_MAGIC;
 885                 msgbufp->msg_size = (char *)msgbufp - cp;
 886         }
 887         msgbufp->msg_ptr = cp;
 888         if (msgbufmapped && oldp != msgbufp)
 889                 msgbufcopy(oldp);
 890         msgbufmapped = 1;
 891         oldp = msgbufp;
 892 }
 893
 894 /* Sysctls for accessing/clearing the msgbuf */
 895
 896 static int
 897 sysctl_kern_msgbuf(SYSCTL_HANDLER_ARGS)
 898 {
 899         struct ucred *cred;
 900         int error;
 901
 902         /*
 903          * Only wheel or root can access the message log.
 904          */
 905         if (unprivileged_read_msgbuf == 0) {
 906                 KKASSERT(req->td->td_proc);
 907                 cred = req->td->td_proc->p_ucred;
 908
 909                 if ((cred->cr_prison || groupmember(0, cred) == 0) &&
 910                     suser(req->td) != 0
 911                 ) {
 912                         return (EPERM);
 913                 }
 914         }
 915
 916         /*
 917          * Unwind the buffer, so that it's linear (possibly starting with
 918          * some initial nulls).
 919          */
 920         error = sysctl_handle_opaque(oidp, msgbufp->msg_ptr + msgbufp->msg_bufx,
 921             msgbufp->msg_size - msgbufp->msg_bufx, req);
 922         if (error)
 923                 return (error);
 924         if (msgbufp->msg_bufx > 0) {
 925                 error = sysctl_handle_opaque(oidp, msgbufp->msg_ptr,
 926                     msgbufp->msg_bufx, req);
 927         }
 928         return (error);
 929 }
 930
 931 SYSCTL_PROC(_kern, OID_AUTO, msgbuf, CTLTYPE_STRING | CTLFLAG_RD,
 932     0, 0, sysctl_kern_msgbuf, "A", "Contents of kernel message buffer");
 933
 934 static int msgbuf_clear;
 935
 936 static int
 937 sysctl_kern_msgbuf_clear(SYSCTL_HANDLER_ARGS)
 938 {
 939         int error;
 940         error = sysctl_handle_int(oidp, oidp->oid_arg1, oidp->oid_arg2, req);
 941         if (!error && req->newptr) {
 942                 /* Clear the buffer and reset write pointer */
 943                 bzero(msgbufp->msg_ptr, msgbufp->msg_size);
 944                 msgbufp->msg_bufr = msgbufp->msg_bufx = 0;
 945                 msgbuf_clear = 0;
 946         }
 947         return (error);
 948 }
 949
 950 SYSCTL_PROC(_kern, OID_AUTO, msgbuf_clear,
 951     CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_SECURE, &msgbuf_clear, 0,
 952     sysctl_kern_msgbuf_clear, "I", "Clear kernel message buffer");
 953
 954 #ifdef DDB
 955
 956 DB_SHOW_COMMAND(msgbuf, db_show_msgbuf)
 957 {
 958         int i, j;
 959
 960         if (!msgbufmapped) {
 961                 db_printf("msgbuf not mapped yet\n");
 962                 return;
 963         }
 964         db_printf("msgbufp = %p\n", msgbufp);
 965         db_printf("magic = %x, size = %d, r= %d, w = %d, ptr = %p\n",
 966             msgbufp->msg_magic, msgbufp->msg_size, msgbufp->msg_bufr,
 967             msgbufp->msg_bufx, msgbufp->msg_ptr);
 968         for (i = 0; i < msgbufp->msg_size; i++) {
 969                 j = (i + msgbufp->msg_bufr) % msgbufp->msg_size;
 970                 db_printf("%c", msgbufp->msg_ptr[j]);
 971         }
 972         db_printf("\n");
 973 }
 974
 975 #endif /* DDB */