subr_prf.c

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/*-
 * Copyright (c) 1986, 1988, 1991, 1993
 *      The Regents of the University of California.  All rights reserved.
 * (c) UNIX System Laboratories, Inc.
 * All or some portions of this file are derived from material licensed
 * to the University of California by American Telephone and Telegraph
 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
 * the permission of UNIX System Laboratories, Inc.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *      @(#)subr_prf.c  8.3 (Berkeley) 1/21/94
 */

#include <sys/cdefs.h>
__FBSDID("$BSDSUniX$");

#include "opt_ddb.h"
#include "opt_printf.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/lock.h>
#include <sys/kdb.h>
#include <sys/mutex.h>
#include <sys/sx.h>
#include <sys/kernel.h>
#include <sys/msgbuf.h>
#include <sys/malloc.h>
#include <sys/priv.h>
#include <sys/proc.h>
#include <sys/stddef.h>
#include <sys/sysctl.h>
#include <sys/tty.h>
#include <sys/syslog.h>
#include <sys/cons.h>
#include <sys/uio.h>
#include <sys/ctype.h>

#ifdef DDB
#include <ddb/ddb.h>
#endif

/*
 * Note that stdarg.h and the ANSI style va_start macro is used for both
 * ANSI and traditional C compilers.
 */
#include <machine/stdarg.h>

#define TOCONS  0x01
#define TOTTY   0x02
#define TOLOG   0x04

/* Max number conversion buffer length: a u_quad_t in base 2, plus NUL byte. */
#define MAXNBUF (sizeof(intmax_t) * NBBY + 1)

struct putchar_arg {
        int     flags;
        int     pri;
        struct  tty *tty;
        char    *p_bufr;
        size_t  n_bufr;
        char    *p_next;
        size_t  remain;
};

struct snprintf_arg {
        char    *str;
        size_t  remain;
};

extern  int log_open;

static void  msglogchar(int c, int pri);
static void  msglogstr(char *str, int pri, int filter_cr);
static void  putchar(int ch, void *arg);
static char *ksprintn(char *nbuf, uintmax_t num, int base, int *len, int upper);
static void  snprintf_func(int ch, void *arg);

static int msgbufmapped;                /* Set when safe to use msgbuf */
int msgbuftrigger;

static int      log_console_output = 1;
TUNABLE_INT("kern.log_console_output", &log_console_output);
SYSCTL_INT(_kern, OID_AUTO, log_console_output, CTLFLAG_RW,
    &log_console_output, 0, "Duplicate console output to the syslog.");

/*
 * See the comment in log_console() below for more explanation of this.
 */
static int log_console_add_linefeed = 0;
TUNABLE_INT("kern.log_console_add_linefeed", &log_console_add_linefeed);
SYSCTL_INT(_kern, OID_AUTO, log_console_add_linefeed, CTLFLAG_RW,
    &log_console_add_linefeed, 0, "log_console() adds extra newlines.");

static int      always_console_output = 0;
TUNABLE_INT("kern.always_console_output", &always_console_output);
SYSCTL_INT(_kern, OID_AUTO, always_console_output, CTLFLAG_RW,
    &always_console_output, 0, "Always output to console despite TIOCCONS.");

/*
 * Warn that a system table is full.
 */
void
tablefull(const char *tab)
{

        log(LOG_ERR, "%s: table is full\n", tab);
}

/*
 * Uprintf prints to the controlling terminal for the current process.
 */
int
uprintf(const char *fmt, ...)
{
        va_list ap;
        struct putchar_arg pca;
        struct proc *p;
        struct thread *td;
        int retval;

        td = curthread;
        if (TD_IS_IDLETHREAD(td))
                return (0);

        sx_slock(&proctree_lock);
        p = td->td_proc;
        PROC_LOCK(p);
        if ((p->p_flag & P_CONTROLT) == 0) {
                PROC_UNLOCK(p);
                sx_sunlock(&proctree_lock);
                return (0);
        }
        SESS_LOCK(p->p_session);
        pca.tty = p->p_session->s_ttyp;
        SESS_UNLOCK(p->p_session);
        PROC_UNLOCK(p);
        if (pca.tty == NULL) {
                sx_sunlock(&proctree_lock);
                return (0);
        }
        pca.flags = TOTTY;
        pca.p_bufr = NULL;
        va_start(ap, fmt);
        tty_lock(pca.tty);
        sx_sunlock(&proctree_lock);
        retval = kvprintf(fmt, putchar, &pca, 10, ap);
        tty_unlock(pca.tty);
        va_end(ap);
        return (retval);
}

/*
 * tprintf prints on the controlling terminal associated with the given
 * session, possibly to the log as well.
 */
void
tprintf(struct proc *p, int pri, const char *fmt, ...)
{
        struct tty *tp = NULL;
        int flags = 0;
        va_list ap;
        struct putchar_arg pca;
        struct session *sess = NULL;

        sx_slock(&proctree_lock);
        if (pri != -1)
                flags |= TOLOG;
        if (p != NULL) {
                PROC_LOCK(p);
                if (p->p_flag & P_CONTROLT && p->p_session->s_ttyvp) {
                        sess = p->p_session;
                        sess_hold(sess);
                        PROC_UNLOCK(p);
                        tp = sess->s_ttyp;
                        if (tp != NULL && tty_checkoutq(tp))
                                flags |= TOTTY;
                        else
                                tp = NULL;
                } else
                        PROC_UNLOCK(p);
        }
        pca.pri = pri;
        pca.tty = tp;
        pca.flags = flags;
        pca.p_bufr = NULL;
        va_start(ap, fmt);
        if (pca.tty != NULL)
                tty_lock(pca.tty);
        sx_sunlock(&proctree_lock);
        kvprintf(fmt, putchar, &pca, 10, ap);
        if (pca.tty != NULL)
                tty_unlock(pca.tty);
        va_end(ap);
        if (sess != NULL)
                sess_release(sess);
        msgbuftrigger = 1;
}

/*
 * Ttyprintf displays a message on a tty; it should be used only by
 * the tty driver, or anything that knows the underlying tty will not
 * be revoke(2)'d away.  Other callers should use tprintf.
 */
int
ttyprintf(struct tty *tp, const char *fmt, ...)
{
        va_list ap;
        struct putchar_arg pca;
        int retval;

        va_start(ap, fmt);
        pca.tty = tp;
        pca.flags = TOTTY;
        pca.p_bufr = NULL;
        retval = kvprintf(fmt, putchar, &pca, 10, ap);
        va_end(ap);
        return (retval);
}

static int
_vprintf(int level, int flags, const char *fmt, va_list ap)
{
        struct putchar_arg pca;
        int retval;
#ifdef PRINTF_BUFR_SIZE
        char bufr[PRINTF_BUFR_SIZE];
#endif

        pca.tty = NULL;
        pca.pri = level;
        pca.flags = flags;
#ifdef PRINTF_BUFR_SIZE
        pca.p_bufr = bufr;
        pca.p_next = pca.p_bufr;
        pca.n_bufr = sizeof(bufr);
        pca.remain = sizeof(bufr);
        *pca.p_next = '\0';
#else
        /* Don't buffer console output. */
        pca.p_bufr = NULL;
#endif

        retval = kvprintf(fmt, putchar, &pca, 10, ap);

#ifdef PRINTF_BUFR_SIZE
        /* Write any buffered console/log output: */
        if (*pca.p_bufr != '\0') {
                if (pca.flags & TOLOG)
                        msglogstr(pca.p_bufr, level, /*filter_cr*/1);

                if (pca.flags & TOCONS)
                        cnputs(pca.p_bufr);
        }
#endif

        return (retval);
}

/*
 * Log writes to the log buffer, and guarantees not to sleep (so can be
 * called by interrupt routines).  If there is no process reading the
 * log yet, it writes to the console also.
 */
void
log(int level, const char *fmt, ...)
{
        va_list ap;

        va_start(ap, fmt);
        (void)_vprintf(level, log_open ? TOLOG : TOCONS, fmt, ap);
        va_end(ap);

        msgbuftrigger = 1;
}

#define CONSCHUNK 128

void
log_console(struct uio *uio)
{
        int c, error, nl;
        char *consbuffer;
        int pri;

        if (!log_console_output)
                return;

        pri = LOG_INFO | LOG_CONSOLE;
        uio = cloneuio(uio);
        consbuffer = malloc(CONSCHUNK, M_TEMP, M_WAITOK);

        nl = 0;
        while (uio->uio_resid > 0) {
                c = imin(uio->uio_resid, CONSCHUNK - 1);
                error = uiomove(consbuffer, c, uio);
                if (error != 0)
                        break;
                /* Make sure we're NUL-terminated */
                consbuffer[c] = '\0';
                if (consbuffer[c - 1] == '\n')
                        nl = 1;
                else
                        nl = 0;
                msglogstr(consbuffer, pri, /*filter_cr*/ 1);
        }
        /*
         * The previous behavior in log_console() is preserved when
         * log_console_add_linefeed is non-zero.  For that behavior, if an
         * individual console write came in that was not terminated with a
         * line feed, it would add a line feed.
         *
         * This results in different data in the message buffer than
         * appears on the system console (which doesn't add extra line feed
         * characters).
         *
         * A number of programs and rc scripts write a line feed, or a period
         * and a line feed when they have completed their operation.  On
         * the console, this looks seamless, but when displayed with
         * 'dmesg -a', you wind up with output that looks like this:
         *
         * Updating motd:
         * .
         *
         * On the console, it looks like this:
         * Updating motd:.
         *
         * We could add logic to detect that situation, or just not insert
         * the extra newlines.  Set the kern.log_console_add_linefeed
         * sysctl/tunable variable to get the old behavior.
         */
        if (!nl && log_console_add_linefeed) {
                consbuffer[0] = '\n';
                consbuffer[1] = '\0';
                msglogstr(consbuffer, pri, /*filter_cr*/ 1);
        }
        msgbuftrigger = 1;
        free(uio, M_IOV);
        free(consbuffer, M_TEMP);
        return;
}

int
printf(const char *fmt, ...)
{
        va_list ap;
        int retval;

        va_start(ap, fmt);
        retval = vprintf(fmt, ap);
        va_end(ap);

        return (retval);
}

int
vprintf(const char *fmt, va_list ap)
{
        int retval;

        retval = _vprintf(-1, TOCONS | TOLOG, fmt, ap);

        if (!panicstr)
                msgbuftrigger = 1;

        return (retval);
}

static void
putbuf(int c, struct putchar_arg *ap)
{
        /* Check if no console output buffer was provided. */
        if (ap->p_bufr == NULL) {
                /* Output direct to the console. */
                if (ap->flags & TOCONS)
                        cnputc(c);

                if (ap->flags & TOLOG)
                        msglogchar(c, ap->pri);
        } else {
                /* Buffer the character: */
                *ap->p_next++ = c;
                ap->remain--;

                /* Always leave the buffer zero terminated. */
                *ap->p_next = '\0';

                /* Check if the buffer needs to be flushed. */
                if (ap->remain == 2 || c == '\n') {

                        if (ap->flags & TOLOG)
                                msglogstr(ap->p_bufr, ap->pri, /*filter_cr*/1);

                        if (ap->flags & TOCONS) {
                                if ((panicstr == NULL) && (constty != NULL))
                                        msgbuf_addstr(&consmsgbuf, -1,
                                            ap->p_bufr, /*filter_cr*/ 0);

                                if ((constty == NULL) ||(always_console_output))
                                        cnputs(ap->p_bufr);
                        }

                        ap->p_next = ap->p_bufr;
                        ap->remain = ap->n_bufr;
                        *ap->p_next = '\0';
                }

                /*
                 * Since we fill the buffer up one character at a time,
                 * this should not happen.  We should always catch it when
                 * ap->remain == 2 (if not sooner due to a newline), flush
                 * the buffer and move on.  One way this could happen is
                 * if someone sets PRINTF_BUFR_SIZE to 1 or something
                 * similarly silly.
                 */
                KASSERT(ap->remain > 2, ("Bad buffer logic, remain = %zd",
                    ap->remain));
        }
}

/*
 * Print a character on console or users terminal.  If destination is
 * the console then the last bunch of characters are saved in msgbuf for
 * inspection later.
 */
static void
putchar(int c, void *arg)
{
        struct putchar_arg *ap = (struct putchar_arg*) arg;
        struct tty *tp = ap->tty;
        int flags = ap->flags;
        int putbuf_done = 0;

        /* Don't use the tty code after a panic or while in ddb. */
        if (kdb_active) {
                if (c != '\0')
                        cnputc(c);
        } else {
                if ((panicstr == NULL) && (flags & TOTTY) && (tp != NULL))
                        tty_putchar(tp, c);

                if (flags & TOCONS) {
                        putbuf(c, ap);
                        putbuf_done = 1;
                }
        }
        if ((flags & TOLOG) && (putbuf_done == 0)) {
                if (c != '\0')
                        putbuf(c, ap);
        }
}

/*
 * Scaled down version of sprintf(3).
 */
int
sprintf(char *buf, const char *cfmt, ...)
{
        int retval;
        va_list ap;

        va_start(ap, cfmt);
        retval = kvprintf(cfmt, NULL, (void *)buf, 10, ap);
        buf[retval] = '\0';
        va_end(ap);
        return (retval);
}

/*
 * Scaled down version of vsprintf(3).
 */
int
vsprintf(char *buf, const char *cfmt, va_list ap)
{
        int retval;

        retval = kvprintf(cfmt, NULL, (void *)buf, 10, ap);
        buf[retval] = '\0';
        return (retval);
}

/*
 * Scaled down version of snprintf(3).
 */
int
snprintf(char *str, size_t size, const char *format, ...)
{
        int retval;
        va_list ap;

        va_start(ap, format);
        retval = vsnprintf(str, size, format, ap);
        va_end(ap);
        return(retval);
}

/*
 * Scaled down version of vsnprintf(3).
 */
int
vsnprintf(char *str, size_t size, const char *format, va_list ap)
{
        struct snprintf_arg info;
        int retval;

        info.str = str;
        info.remain = size;
        retval = kvprintf(format, snprintf_func, &info, 10, ap);
        if (info.remain >= 1)
                *info.str++ = '\0';
        return (retval);
}

/*
 * Kernel version which takes radix argument vsnprintf(3).
 */
int
vsnrprintf(char *str, size_t size, int radix, const char *format, va_list ap)
{
        struct snprintf_arg info;
        int retval;

        info.str = str;
        info.remain = size;
        retval = kvprintf(format, snprintf_func, &info, radix, ap);
        if (info.remain >= 1)
                *info.str++ = '\0';
        return (retval);
}

static void
snprintf_func(int ch, void *arg)
{
        struct snprintf_arg *const info = arg;

        if (info->remain >= 2) {
                *info->str++ = ch;
                info->remain--;
        }
}

/*
 * Put a NUL-terminated ASCII number (base <= 36) in a buffer in reverse
 * order; return an optional length and a pointer to the last character
 * written in the buffer (i.e., the first character of the string).
 * The buffer pointed to by `nbuf' must have length >= MAXNBUF.
 */
static char *
ksprintn(char *nbuf, uintmax_t num, int base, int *lenp, int upper)
{
        char *p, c;

        p = nbuf;
        *p = '\0';
        do {
                c = hex2ascii(num % base);
                *++p = upper ? toupper(c) : c;
        } while (num /= base);
        if (lenp)
                *lenp = p - nbuf;
        return (p);
}

/*
 * Scaled down version of printf(3).
 *
 * Two additional formats:
 *
 * The format %b is supported to decode error registers.
 * Its usage is:
 *
 *      printf("reg=%b\n", regval, "<base><arg>*");
 *
 * where <base> is the output base expressed as a control character, e.g.
 * \10 gives octal; \20 gives hex.  Each arg is a sequence of characters,
 * the first of which gives the bit number to be inspected (origin 1), and
 * the next characters (up to a control character, i.e. a character <= 32),
 * give the name of the register.  Thus:
 *
 *      kvprintf("reg=%b\n", 3, "\10\2BITTWO\1BITONE\n");
 *
 * would produce output:
 *
 *      reg=3<BITTWO,BITONE>
 *
 * XXX:  %D  -- Hexdump, takes pointer and separator string:
 *              ("%6D", ptr, ":")   -> XX:XX:XX:XX:XX:XX
 *              ("%*D", len, ptr, " " -> XX XX XX XX ...
 */
int
kvprintf(char const *fmt, void (*func)(int, void*), void *arg, int radix, va_list ap)
{
#define PCHAR(c) {int cc=(c); if (func) (*func)(cc,arg); else *d++ = cc; retval++; }
        char nbuf[MAXNBUF];
        char *d;
        const char *p, *percent, *q;
        u_char *up;
        int ch, n;
        uintmax_t num;
        int base, lflag, qflag, tmp, width, ladjust, sharpflag, neg, sign, dot;
        int cflag, hflag, jflag, tflag, zflag;
        int dwidth, upper;
        char padc;
        int stop = 0, retval = 0;

        num = 0;
        if (!func)
                d = (char *) arg;
        else
                d = NULL;

        if (fmt == NULL)
                fmt = "(fmt null)\n";

        if (radix < 2 || radix > 36)
                radix = 10;

        for (;;) {
                padc = ' ';
                width = 0;
                while ((ch = (u_char)*fmt++) != '%' || stop) {
                        if (ch == '\0')
                                return (retval);
                        PCHAR(ch);
                }
                percent = fmt - 1;
                qflag = 0; lflag = 0; ladjust = 0; sharpflag = 0; neg = 0;
                sign = 0; dot = 0; dwidth = 0; upper = 0;
                cflag = 0; hflag = 0; jflag = 0; tflag = 0; zflag = 0;
reswitch:       switch (ch = (u_char)*fmt++) {
                case '.':
                        dot = 1;
                        goto reswitch;
                case '#':
                        sharpflag = 1;
                        goto reswitch;
                case '+':
                        sign = 1;
                        goto reswitch;
                case '-':
                        ladjust = 1;
                        goto reswitch;
                case '%':
                        PCHAR(ch);
                        break;
                case '*':
                        if (!dot) {
                                width = va_arg(ap, int);
                                if (width < 0) {
                                        ladjust = !ladjust;
                                        width = -width;
                                }
                        } else {
                                dwidth = va_arg(ap, int);
                        }
                        goto reswitch;
                case '0':
                        if (!dot) {
                                padc = '0';
                                goto reswitch;
                        }
                case '1': case '2': case '3': case '4':
                case '5': case '6': case '7': case '8': case '9':
                                for (n = 0;; ++fmt) {
                                        n = n * 10 + ch - '0';
                                        ch = *fmt;
                                        if (ch < '0' || ch > '9')
                                                break;
                                }
                        if (dot)
                                dwidth = n;
                        else
                                width = n;
                        goto reswitch;
                case 'b':
                        num = (u_int)va_arg(ap, int);
                        p = va_arg(ap, char *);
                        for (q = ksprintn(nbuf, num, *p++, NULL, 0); *q;)
                                PCHAR(*q--);

                        if (num == 0)
                                break;

                        for (tmp = 0; *p;) {
                                n = *p++;
                                if (num & (1 << (n - 1))) {
                                        PCHAR(tmp ? ',' : '<');
                                        for (; (n = *p) > ' '; ++p)
                                                PCHAR(n);
                                        tmp = 1;
                                } else
                                        for (; *p > ' '; ++p)
                                                continue;
                        }
                        if (tmp)
                                PCHAR('>');
                        break;
                case 'c':
                        PCHAR(va_arg(ap, int));
                        break;
                case 'D':
                        up = va_arg(ap, u_char *);
                        p = va_arg(ap, char *);
                        if (!width)
                                width = 16;
                        while(width--) {
                                PCHAR(hex2ascii(*up >> 4));
                                PCHAR(hex2ascii(*up & 0x0f));
                                up++;
                                if (width)
                                        for (q=p;*q;q++)
                                                PCHAR(*q);
                        }
                        break;
                case 'd':
                case 'i':
                        base = 10;
                        sign = 1;
                        goto handle_sign;
                case 'h':
                        if (hflag) {
                                hflag = 0;
                                cflag = 1;
                        } else
                                hflag = 1;
                        goto reswitch;
                case 'j':
                        jflag = 1;
                        goto reswitch;
                case 'l':
                        if (lflag) {
                                lflag = 0;
                                qflag = 1;
                        } else
                                lflag = 1;
                        goto reswitch;
                case 'n':
                        if (jflag)
                                *(va_arg(ap, intmax_t *)) = retval;
                        else if (qflag)
                                *(va_arg(ap, quad_t *)) = retval;
                        else if (lflag)
                                *(va_arg(ap, long *)) = retval;
                        else if (zflag)
                                *(va_arg(ap, size_t *)) = retval;
                        else if (hflag)
                                *(va_arg(ap, short *)) = retval;
                        else if (cflag)
                                *(va_arg(ap, char *)) = retval;
                        else
                                *(va_arg(ap, int *)) = retval;
                        break;
                case 'o':
                        base = 8;
                        goto handle_nosign;
                case 'p':
                        base = 16;
                        sharpflag = (width == 0);
                        sign = 0;
                        num = (uintptr_t)va_arg(ap, void *);
                        goto number;
                case 'q':
                        qflag = 1;
                        goto reswitch;
                case 'r':
                        base = radix;
                        if (sign)
                                goto handle_sign;
                        goto handle_nosign;
                case 's':
                        p = va_arg(ap, char *);
                        if (p == NULL)
                                p = "(null)";
                        if (!dot)
                                n = strlen (p);
                        else
                                for (n = 0; n < dwidth && p[n]; n++)
                                        continue;

                        width -= n;

                        if (!ladjust && width > 0)
                                while (width--)
                                        PCHAR(padc);
                        while (n--)
                                PCHAR(*p++);
                        if (ladjust && width > 0)
                                while (width--)
                                        PCHAR(padc);
                        break;
                case 't':
                        tflag = 1;
                        goto reswitch;
                case 'u':
                        base = 10;
                        goto handle_nosign;
                case 'X':
                        upper = 1;
                case 'x':
                        base = 16;
                        goto handle_nosign;
                case 'y':
                        base = 16;
                        sign = 1;
                        goto handle_sign;
                case 'z':
                        zflag = 1;
                        goto reswitch;
handle_nosign:
                        sign = 0;
                        if (jflag)
                                num = va_arg(ap, uintmax_t);
                        else if (qflag)
                                num = va_arg(ap, u_quad_t);
                        else if (tflag)
                                num = va_arg(ap, ptrdiff_t);
                        else if (lflag)
                                num = va_arg(ap, u_long);
                        else if (zflag)
                                num = va_arg(ap, size_t);
                        else if (hflag)
                                num = (u_short)va_arg(ap, int);
                        else if (cflag)
                                num = (u_char)va_arg(ap, int);
                        else
                                num = va_arg(ap, u_int);
                        goto number;
handle_sign:
                        if (jflag)
                                num = va_arg(ap, intmax_t);
                        else if (qflag)
                                num = va_arg(ap, quad_t);
                        else if (tflag)
                                num = va_arg(ap, ptrdiff_t);
                        else if (lflag)
                                num = va_arg(ap, long);
                        else if (zflag)
                                num = va_arg(ap, ssize_t);
                        else if (hflag)
                                num = (short)va_arg(ap, int);
                        else if (cflag)
                                num = (char)va_arg(ap, int);
                        else
                                num = va_arg(ap, int);
number:
                        if (sign && (intmax_t)num < 0) {
                                neg = 1;
                                num = -(intmax_t)num;
                        }
                        p = ksprintn(nbuf, num, base, &n, upper);
                        tmp = 0;
                        if (sharpflag && num != 0) {
                                if (base == 8)
                                        tmp++;
                                else if (base == 16)
                                        tmp += 2;
                        }
                        if (neg)
                                tmp++;

                        if (!ladjust && padc == '0')
                                dwidth = width - tmp;
                        width -= tmp + imax(dwidth, n);
                        dwidth -= n;
                        if (!ladjust)
                                while (width-- > 0)
                                        PCHAR(' ');
                        if (neg)
                                PCHAR('-');
                        if (sharpflag && num != 0) {
                                if (base == 8) {
                                        PCHAR('0');
                                } else if (base == 16) {
                                        PCHAR('0');
                                        PCHAR('x');
                                }
                        }
                        while (dwidth-- > 0)
                                PCHAR('0');

                        while (*p)
                                PCHAR(*p--);

                        if (ladjust)
                                while (width-- > 0)
                                        PCHAR(' ');

                        break;
                default:
                        while (percent < fmt)
                                PCHAR(*percent++);
                        /*
                         * Since we ignore an formatting argument it is no 
                         * longer safe to obey the remaining formatting
                         * arguments as the arguments will no longer match
                         * the format specs.
                         */
                        stop = 1;
                        break;
                }
        }
#undef PCHAR
}

/*
 * Put character in log buffer with a particular priority.
 */
static void
msglogchar(int c, int pri)
{
        static int lastpri = -1;
        static int dangling;
        char nbuf[MAXNBUF];
        char *p;

        if (!msgbufmapped)
                return;
        if (c == '\0' || c == '\r')
                return;
        if (pri != -1 && pri != lastpri) {
                if (dangling) {
                        msgbuf_addchar(msgbufp, '\n');
                        dangling = 0;
                }
                msgbuf_addchar(msgbufp, '<');
                for (p = ksprintn(nbuf, (uintmax_t)pri, 10, NULL, 0); *p;)
                        msgbuf_addchar(msgbufp, *p--);
                msgbuf_addchar(msgbufp, '>');
                lastpri = pri;
        }
        msgbuf_addchar(msgbufp, c);
        if (c == '\n') {
                dangling = 0;
                lastpri = -1;
        } else {
                dangling = 1;
        }
}

static void
msglogstr(char *str, int pri, int filter_cr)
{
        if (!msgbufmapped)
                return;

        msgbuf_addstr(msgbufp, pri, str, filter_cr);
}

void
msgbufinit(void *ptr, int size)
{
        char *cp;
        static struct msgbuf *oldp = NULL;

        size -= sizeof(*msgbufp);
        cp = (char *)ptr;
        msgbufp = (struct msgbuf *)(cp + size);
        msgbuf_reinit(msgbufp, cp, size);
        if (msgbufmapped && oldp != msgbufp)
                msgbuf_copy(oldp, msgbufp);
        msgbufmapped = 1;
        oldp = msgbufp;
}

static int unprivileged_read_msgbuf = 1;
SYSCTL_INT(_security_bsd, OID_AUTO, unprivileged_read_msgbuf,
    CTLFLAG_RW, &unprivileged_read_msgbuf, 0,
    "Unprivileged processes may read the kernel message buffer");

/* Sysctls for accessing/clearing the msgbuf */
static int
sysctl_kern_msgbuf(SYSCTL_HANDLER_ARGS)
{
        char buf[128];
        u_int seq;
        int error, len;

        if (!unprivileged_read_msgbuf) {
                error = priv_check(req->td, PRIV_MSGBUF);
                if (error)
                        return (error);
        }

        /* Read the whole buffer, one chunk at a time. */
        mtx_lock(&msgbuf_lock);
        msgbuf_peekbytes(msgbufp, NULL, 0, &seq);
        for (;;) {
                len = msgbuf_peekbytes(msgbufp, buf, sizeof(buf), &seq);
                mtx_unlock(&msgbuf_lock);
                if (len == 0)
                        return (0);

                error = sysctl_handle_opaque(oidp, buf, len, req);
                if (error)
                        return (error);

                mtx_lock(&msgbuf_lock);
        }
}

SYSCTL_PROC(_kern, OID_AUTO, msgbuf,
    CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE,
    NULL, 0, sysctl_kern_msgbuf, "A", "Contents of kernel message buffer");

static int msgbuf_clearflag;

static int
sysctl_kern_msgbuf_clear(SYSCTL_HANDLER_ARGS)
{
        int error;
        error = sysctl_handle_int(oidp, oidp->oid_arg1, oidp->oid_arg2, req);
        if (!error && req->newptr) {
                mtx_lock(&msgbuf_lock);
                msgbuf_clear(msgbufp);
                mtx_unlock(&msgbuf_lock);
                msgbuf_clearflag = 0;
        }
        return (error);
}

SYSCTL_PROC(_kern, OID_AUTO, msgbuf_clear,
    CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_SECURE | CTLFLAG_MPSAFE,
    &msgbuf_clearflag, 0, sysctl_kern_msgbuf_clear, "I",
    "Clear kernel message buffer");

#ifdef DDB

DB_SHOW_COMMAND(msgbuf, db_show_msgbuf)
{
        int i, j;

        if (!msgbufmapped) {
                db_printf("msgbuf not mapped yet\n");
                return;
        }
        db_printf("msgbufp = %p\n", msgbufp);
        db_printf("magic = %x, size = %d, r= %u, w = %u, ptr = %p, cksum= %u\n",
            msgbufp->msg_magic, msgbufp->msg_size, msgbufp->msg_rseq,
            msgbufp->msg_wseq, msgbufp->msg_ptr, msgbufp->msg_cksum);
        for (i = 0; i < msgbufp->msg_size && !db_pager_quit; i++) {
                j = MSGBUF_SEQ_TO_POS(msgbufp, i + msgbufp->msg_rseq);
                db_printf("%c", msgbufp->msg_ptr[j]);
        }
        db_printf("\n");
}

#endif /* DDB */

void
hexdump(const void *ptr, int length, const char *hdr, int flags)
{
        int i, j, k;
        int cols;
        const unsigned char *cp;
        char delim;

        if ((flags & HD_DELIM_MASK) != 0)
                delim = (flags & HD_DELIM_MASK) >> 8;
        else
                delim = ' ';

        if ((flags & HD_COLUMN_MASK) != 0)
                cols = flags & HD_COLUMN_MASK;
        else
                cols = 16;

        cp = ptr;
        for (i = 0; i < length; i+= cols) {
                if (hdr != NULL)
                        printf("%s", hdr);

                if ((flags & HD_OMIT_COUNT) == 0)
                        printf("%04x  ", i);

                if ((flags & HD_OMIT_HEX) == 0) {
                        for (j = 0; j < cols; j++) {
                                k = i + j;
                                if (k < length)
                                        printf("%c%02x", delim, cp[k]);
                                else
                                        printf("   ");
                        }
                }

                if ((flags & HD_OMIT_CHARS) == 0) {
                        printf("  |");
                        for (j = 0; j < cols; j++) {
                                k = i + j;
                                if (k >= length)
                                        printf(" ");
                                else if (cp[k] >= ' ' && cp[k] <= '~')
                                        printf("%c", cp[k]);
                                else
                                        printf(".");
                        }
                        printf("|");
                }
                printf("\n");
        }
}