/*      $OpenBSD: subr_prf.c,v 1.106 2022/08/14 01:58:28 jsg Exp $      */
/*      $NetBSD: subr_prf.c,v 1.45 1997/10/24 18:14:25 chuck Exp $      */

/*-
 * 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.
 * 3. 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/param.h>
#include <sys/systm.h>
#include <sys/reboot.h>
#include <sys/msgbuf.h>
#include <sys/proc.h>
#include <sys/tty.h>
#include <sys/tprintf.h>
#include <sys/syslog.h>
#include <sys/pool.h>
#include <sys/mutex.h>

#include <dev/cons.h>

/*
 * note that stdarg.h and the ansi style va_start macro is used for both
 * ansi and traditional c compilers.
 */
#include <sys/stdarg.h>

#ifdef DDB
#include <ddb/db_output.h>      /* db_printf, db_putchar prototypes */
#include <ddb/db_var.h>         /* db_log, db_radix */
#endif


/*
 * defines
 */

/* flags for kprintf */
#define TOCONS          0x01    /* to the console */
#define TOTTY           0x02    /* to the process' tty */
#define TOLOG           0x04    /* to the kernel message buffer */
#define TOBUFONLY       0x08    /* to the buffer (only) [for snprintf] */
#define TODDB           0x10    /* to ddb console */
#define TOCOUNT         0x20    /* act like [v]snprintf */

/* max size buffer kprintf needs to print quad_t [size in base 8 + \0] */
#define KPRINTF_BUFSIZE         (sizeof(quad_t) * NBBY / 3 + 2)


/*
 * local prototypes
 */

int      kprintf(const char *, int, void *, char *, va_list);
void     kputchar(int, int, struct tty *);

struct mutex kprintf_mutex =
    MUTEX_INITIALIZER_FLAGS(IPL_HIGH, "kprintf", MTX_NOWITNESS);

/*
 * globals
 */

extern  int log_open;   /* subr_log: is /dev/klog open? */
const   char *panicstr; /* arg to first call to panic (used as a flag
                           to indicate that panic has already been called). */
#ifdef DDB
/*
 * Enter ddb on panic.
 */
int     db_panic = 1;

/*
 * db_console controls if we can be able to enter ddb by a special key
 * combination (machine dependent).
 * If DDB_SAFE_CONSOLE is defined in the kernel configuration it allows
 * to break into console during boot. It's _really_ useful when debugging
 * some things in the kernel that can cause init(8) to crash.
 */
#ifdef DDB_SAFE_CONSOLE
int     db_console = 1;
#else
int     db_console = 0;
#endif
#endif

/*
 * panic on spl assertion failure?
 */
#ifdef SPLASSERT_WATCH
int splassert_ctl = 3;
#else
int splassert_ctl = 1;
#endif

/*
 * v_putc: routine to putc on virtual console
 *
 * the v_putc pointer can be used to redirect the console cnputc elsewhere
 * [e.g. to a "virtual console"].
 */

void (*v_putc)(int) = cnputc;   /* start with cnputc (normal cons) */

/*
 * Silence kernel printf when masquerading as a bootloader.
 */
#ifdef BOOT_QUIET
int printf_flags = TOLOG;
#else
int printf_flags = TOCONS | TOLOG;
#endif

/*
 * functions
 */

/*
 *      Partial support (the failure case) of the assertion facility
 *      commonly found in userland.
 */
void
__assert(const char *t, const char *f, int l, const char *e)
{

        panic(__KASSERTSTR, t, e, f, l);
}

/*
 * tablefull: warn that a system table is full
 */

void
tablefull(const char *tab)
{
        log(LOG_ERR, "%s: table is full\n", tab);
}

/*
 * If we have panicked, prefer db_printf() and db_vprintf() where
 * available.
 */
#ifdef DDB
#define panic_printf(...)       db_printf(__VA_ARGS__)
#define panic_vprintf(...)      db_vprintf(__VA_ARGS__)
#else
#define panic_printf(...)       printf(__VA_ARGS__)
#define panic_vprintf(...)      vprintf(__VA_ARGS__)
#endif

/*
 * panic: handle an unresolvable fatal error
 *
 * prints "panic: <message>" and reboots.   if called twice (i.e. recursive
 * call) we avoid trying to sync the disk and just reboot (to avoid
 * recursive panics).
 */

void
panic(const char *fmt, ...)
{
        struct cpu_info *ci = curcpu();
        int bootopt;
        va_list ap;

        bootopt = RB_AUTOBOOT | RB_DUMP;
        if (atomic_cas_ptr(&panicstr, NULL, ci->ci_panicbuf) != NULL)
                bootopt |= RB_NOSYNC;

        /* do not trigger assertions, we know that we are inconsistent */
        splassert_ctl = 0;

#ifdef BOOT_QUIET
        printf_flags |= TOCONS; /* make sure we see kernel printf output */
#endif

        /*
         * All panic messages are printed, but only the first panic on a
         * given CPU is written to its panicbuf.
         */
        if (ci->ci_panicbuf[0] == '\0') {
                va_start(ap, fmt);
                vsnprintf(ci->ci_panicbuf, sizeof(ci->ci_panicbuf), fmt, ap);
                va_end(ap);
                panic_printf("panic: %s\n", ci->ci_panicbuf);
        } else {
                panic_printf("panic: ");
                va_start(ap, fmt);
                panic_vprintf(fmt, ap);
                va_end(ap);
                panic_printf("\n");
        }

#ifdef DDB
        if (db_panic)
                db_enter();
        else
                db_stack_dump();
#endif
        reboot(bootopt);
        /* NOTREACHED */
}

/*
 * We print only the function name. The file name is usually very long and
 * would eat tons of space in the kernel.
 */
void
splassert_fail(int wantipl, int haveipl, const char *func)
{
        if (panicstr || db_active)
                return;

        printf("splassert: %s: want %d have %d\n", func, wantipl, haveipl);
        switch (splassert_ctl) {
        case 1:
                break;
        case 2:
#ifdef DDB
                db_stack_dump();
#endif
                break;
        case 3:
#ifdef DDB
                db_stack_dump();
                db_enter();
#endif
                break;
        default:
                panic("spl assertion failure in %s", func);
        }
}

/*
 * kernel logging functions: log, logpri, addlog
 */

/*
 * log: write to the log buffer
 *
 * => will not sleep [so safe to call from interrupt]
 * => will log to console if /dev/klog isn't open
 */

void
log(int level, const char *fmt, ...)
{
        int s;
        va_list ap;

        s = splhigh();
        logpri(level);          /* log the level first */
        va_start(ap, fmt);
        kprintf(fmt, TOLOG, NULL, NULL, ap);
        va_end(ap);
        splx(s);
        if (!log_open) {
                va_start(ap, fmt);
                mtx_enter(&kprintf_mutex);
                kprintf(fmt, TOCONS, NULL, NULL, ap);
                mtx_leave(&kprintf_mutex);
                va_end(ap);
        }
        logwakeup();            /* wake up anyone waiting for log msgs */
}

/*
 * logpri: log the priority level to the klog
 */

void
logpri(int level)
{
        char *p;
        char snbuf[KPRINTF_BUFSIZE];

        kputchar('<', TOLOG, NULL);
        snprintf(snbuf, sizeof snbuf, "%d", level);
        for (p = snbuf ; *p ; p++)
                kputchar(*p, TOLOG, NULL);
        kputchar('>', TOLOG, NULL);
}

/*
 * addlog: add info to previous log message
 */

int
addlog(const char *fmt, ...)
{
        int s;
        va_list ap;

        s = splhigh();
        va_start(ap, fmt);
        kprintf(fmt, TOLOG, NULL, NULL, ap);
        va_end(ap);
        splx(s);
        if (!log_open) {
                va_start(ap, fmt);
                mtx_enter(&kprintf_mutex);
                kprintf(fmt, TOCONS, NULL, NULL, ap);
                mtx_leave(&kprintf_mutex);
                va_end(ap);
        }
        logwakeup();
        return(0);
}


/*
 * kputchar: print a single character on console or user terminal.
 *
 * => if console, then the last MSGBUFS chars are saved in msgbuf
 *      for inspection later (e.g. dmesg/syslog)
 */
void
kputchar(int c, int flags, struct tty *tp)
{
        extern int msgbufmapped;

        if (panicstr)
                constty = NULL;

        if ((flags & TOCONS) && tp == NULL && constty != NULL && !db_active) {
                tp = constty;
                flags |= TOTTY;
        }
        if ((flags & TOTTY) && tp && tputchar(c, tp) < 0 &&
            (flags & TOCONS) && tp == constty)
                constty = NULL;
        if ((flags & TOLOG) &&
            c != '\0' && c != '\r' && c != 0177 && msgbufmapped)
                msgbuf_putchar(msgbufp, c);
        if ((flags & TOCONS) && (constty == NULL || db_active) && c != '\0')
                (*v_putc)(c);
#ifdef DDB
        if (flags & TODDB)
                db_putchar(c);
#endif
}


/*
 * uprintf: print to the controlling tty of the current process
 *
 * => we may block if the tty queue is full
 * => no message is printed if the queue doesn't clear in a reasonable
 *      time
 */

void
uprintf(const char *fmt, ...)
{
        struct process *pr = curproc->p_p;
        va_list ap;

        if (pr->ps_flags & PS_CONTROLT && pr->ps_session->s_ttyvp) {
                va_start(ap, fmt);
                kprintf(fmt, TOTTY, pr->ps_session->s_ttyp, NULL, ap);
                va_end(ap);
        }
}

#if defined(NFSSERVER) || defined(NFSCLIENT)

/*
 * tprintf functions: used to send messages to a specific process
 *
 * usage:
 *   get a tpr_t handle on a process "p" by using "tprintf_open(p)"
 *   use the handle when calling "tprintf"
 *   when done, do a "tprintf_close" to drop the handle
 */

/*
 * tprintf_open: get a tprintf handle on a process "p"
 * XXX change s/proc/process
 *
 * => returns NULL if process can't be printed to
 */

tpr_t
tprintf_open(struct proc *p)
{
        struct process *pr = p->p_p;

        if (pr->ps_flags & PS_CONTROLT && pr->ps_session->s_ttyvp) {
                SESSHOLD(pr->ps_session);
                return ((tpr_t)pr->ps_session);
        }
        return ((tpr_t) NULL);
}

/*
 * tprintf_close: dispose of a tprintf handle obtained with tprintf_open
 */

void
tprintf_close(tpr_t sess)
{

        if (sess)
                SESSRELE((struct session *) sess);
}

/*
 * tprintf: given tprintf handle to a process [obtained with tprintf_open],
 * send a message to the controlling tty for that process.
 *
 * => also sends message to /dev/klog
 */
void
tprintf(tpr_t tpr, const char *fmt, ...)
{
        struct session *sess = (struct session *)tpr;
        struct tty *tp = NULL;
        int flags = TOLOG;
        va_list ap;

        logpri(LOG_INFO);
        if (sess && sess->s_ttyvp && ttycheckoutq(sess->s_ttyp, 0)) {
                flags |= TOTTY;
                tp = sess->s_ttyp;
        }
        va_start(ap, fmt);
        kprintf(fmt, flags, tp, NULL, ap);
        va_end(ap);
        logwakeup();
}

#endif  /* NFSSERVER || NFSCLIENT */


/*
 * ttyprintf: send a message to a specific tty
 *
 * => should be used only by tty driver or anything that knows the
 *      underlying tty will not be revoked(2)'d away.  [otherwise,
 *      use tprintf]
 */
void
ttyprintf(struct tty *tp, const char *fmt, ...)
{
        va_list ap;

        va_start(ap, fmt);
        kprintf(fmt, TOTTY, tp, NULL, ap);
        va_end(ap);
}

#ifdef DDB

/*
 * db_printf: printf for DDB (via db_putchar)
 */

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

        va_start(ap, fmt);
        retval = db_vprintf(fmt, ap);
        va_end(ap);
        return(retval);
}

int
db_vprintf(const char *fmt, va_list ap)
{
        int flags;

        flags = TODDB;
        if (db_log)
                flags |= TOLOG;
        return (kprintf(fmt, flags, NULL, NULL, ap));
}
#endif /* DDB */


/*
 * normal kernel printf functions: printf, vprintf, snprintf
 */

/*
 * printf: print a message to the console and the log
 */
int
printf(const char *fmt, ...)
{
        va_list ap;
        int retval;

        va_start(ap, fmt);
        mtx_enter(&kprintf_mutex);
        retval = kprintf(fmt, printf_flags, NULL, NULL, ap);
        mtx_leave(&kprintf_mutex);
        va_end(ap);
        if (!panicstr)
                logwakeup();


        return(retval);
}

/*
 * vprintf: print a message to the console and the log [already have a
 *      va_list]
 */

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

        mtx_enter(&kprintf_mutex);
        retval = kprintf(fmt, TOCONS | TOLOG, NULL, NULL, ap);
        mtx_leave(&kprintf_mutex);
        if (!panicstr)
                logwakeup();


        return (retval);
}

/*
 * snprintf: print a message to a buffer
 */
int
snprintf(char *buf, size_t size, const char *fmt, ...)
{
        int retval;
        va_list ap;
        char *p;

        p = buf;
        if (size > 0)
                p += size - 1;
        va_start(ap, fmt);
        retval = kprintf(fmt, TOBUFONLY | TOCOUNT, &p, buf, ap);
        va_end(ap);
        if (size > 0)
                *p = '\0';      /* null terminate */
        return(retval);
}

/*
 * vsnprintf: print a message to a buffer [already have va_alist]
 */
int
vsnprintf(char *buf, size_t size, const char *fmt, va_list ap)
{
        int retval;
        char *p;

        p = buf + size - 1;
        if (size < 1)
                p = buf;
        retval = kprintf(fmt, TOBUFONLY | TOCOUNT, &p, buf, ap);
        if (size > 0)
                *(p) = 0;       /* null terminate */
        return(retval);
}

/*
 * kprintf: scaled down version of printf(3).
 *
 * this version based on vfprintf() from libc which was derived from
 * software contributed to Berkeley by Chris Torek.
 *
 * The additional 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:
 *
 *      kprintf("reg=%b\n", 3, "\10\2BITTWO\1BITONE\n");
 *
 * would produce output:
 *
 *      reg=3<BITTWO,BITONE>
 *
 * To support larger integers (> 32 bits), %b formatting will also accept
 * control characters in the region 0x80 - 0xff.  0x80 refers to bit 0,
 * 0x81 refers to bit 1, and so on.  The equivalent string to the above is:
 *
 *      kprintf("reg=%b\n", 3, "\10\201BITTWO\200BITONE\n");
 *
 * and would produce the same output.
 *
 * Like the rest of printf, %b can be prefixed to handle various size
 * modifiers, eg. %b is for "int", %lb is for "long", and %llb supports
 * "long long".
 *
 * This code is large and complicated...
 */

/*
 * macros for converting digits to letters and vice versa
 */
#define to_digit(c)     ((c) - '0')
#define is_digit(c)     ((unsigned)to_digit(c) <= 9)
#define to_char(n)      ((n) + '0')

/*
 * flags used during conversion.
 */
#define ALT             0x001           /* alternate form */
#define HEXPREFIX       0x002           /* add 0x or 0X prefix */
#define LADJUST         0x004           /* left adjustment */
#define LONGDBL         0x008           /* long double; unimplemented */
#define LONGINT         0x010           /* long integer */
#define QUADINT         0x020           /* quad integer */
#define SHORTINT        0x040           /* short integer */
#define ZEROPAD         0x080           /* zero (as opposed to blank) pad */
#define FPT             0x100           /* Floating point number */
#define SIZEINT         0x200           /* (signed) size_t */

        /*
         * To extend shorts properly, we need both signed and unsigned
         * argument extraction methods.
         */
#define SARG() \
        (flags&QUADINT ? va_arg(ap, quad_t) : \
            flags&LONGINT ? va_arg(ap, long) : \
            flags&SIZEINT ? va_arg(ap, ssize_t) : \
            flags&SHORTINT ? (long)(short)va_arg(ap, int) : \
            (long)va_arg(ap, int))
#define UARG() \
        (flags&QUADINT ? va_arg(ap, u_quad_t) : \
            flags&LONGINT ? va_arg(ap, u_long) : \
            flags&SIZEINT ? va_arg(ap, size_t) : \
            flags&SHORTINT ? (u_long)(u_short)va_arg(ap, int) : \
            (u_long)va_arg(ap, u_int))

#define KPRINTF_PUTCHAR(C) do {                                 \
        int chr = (C);                                          \
        ret += 1;                                               \
        if (oflags & TOBUFONLY) {                               \
                if ((vp != NULL) && (sbuf == tailp)) {          \
                        if (!(oflags & TOCOUNT))                \
                                goto overflow;                  \
                } else                                          \
                        *sbuf++ = chr;                          \
        } else {                                                \
                kputchar(chr, oflags, (struct tty *)vp);        \
        }                                                       \
} while(0)

int
kprintf(const char *fmt0, int oflags, void *vp, char *sbuf, va_list ap)
{
        char *fmt;              /* format string */
        int ch;                 /* character from fmt */
        int n;                  /* handy integer (short term usage) */
        char *cp = NULL;        /* handy char pointer (short term usage) */
        int flags;              /* flags as above */
        int ret;                /* return value accumulator */
        int width;              /* width from format (%8d), or 0 */
        int prec;               /* precision from format (%.3d), or -1 */
        char sign;              /* sign prefix (' ', '+', '-', or \0) */

        u_quad_t _uquad;        /* integer arguments %[diouxX] */
        enum { OCT, DEC, HEX } base;/* base for [diouxX] conversion */
        int dprec;              /* a copy of prec if [diouxX], 0 otherwise */
        int realsz;             /* field size expanded by dprec */
        int size = 0;           /* size of converted field or string */
        char *xdigs = NULL;     /* digits for [xX] conversion */
        char buf[KPRINTF_BUFSIZE]; /* space for %c, %[diouxX] */
        char *tailp = NULL;     /* tail pointer for snprintf */

        if (oflags & TOCONS)
                MUTEX_ASSERT_LOCKED(&kprintf_mutex);

        if ((oflags & TOBUFONLY) && (vp != NULL))
                tailp = *(char **)vp;

        fmt = (char *)fmt0;
        ret = 0;

        /*
         * Scan the format for conversions (`%' character).
         */
        for (;;) {
                while (*fmt != '%' && *fmt) {
                        KPRINTF_PUTCHAR(*fmt++);
                }
                if (*fmt == 0)
                        goto done;

                fmt++;          /* skip over '%' */

                flags = 0;
                dprec = 0;
                width = 0;
                prec = -1;
                sign = '\0';

rflag:          ch = *fmt++;
reswitch:       switch (ch) {
                /* XXX: non-standard '%b' format */
                case 'b': {
                        char *b, *z;
                        int tmp;
                        _uquad = UARG();
                        b = va_arg(ap, char *);
                        if (*b == 8)
                                snprintf(buf, sizeof buf, "%llo", _uquad);
                        else if (*b == 10)
                                snprintf(buf, sizeof buf, "%lld", _uquad);
                        else if (*b == 16)
                                snprintf(buf, sizeof buf, "%llx", _uquad);
                        else
                                break;
                        b++;

                        z = buf;
                        while (*z) {
                                KPRINTF_PUTCHAR(*z++);
                        }

                        if (_uquad) {
                                tmp = 0;
                                while ((n = *b++) != 0) {
                                        if (n & 0x80)
                                                n &= 0x7f;
                                        else if (n <= ' ')
                                                n = n - 1;
                                        if (_uquad & (1LL << n)) {
                                                KPRINTF_PUTCHAR(tmp ? ',':'<');
                                                while (*b > ' ' &&
                                                    (*b & 0x80) == 0) {
                                                        KPRINTF_PUTCHAR(*b);
                                                        b++;
                                                }
                                                tmp = 1;
                                        } else {
                                                while (*b > ' ' &&
                                                    (*b & 0x80) == 0)
                                                        b++;
                                        }
                                }
                                if (tmp) {
                                        KPRINTF_PUTCHAR('>');
                                }
                        }
                        continue;       /* no output */
                }

                case ' ':
                        /*
                         * ``If the space and + flags both appear, the space
                         * flag will be ignored.''
                         *      -- ANSI X3J11
                         */
                        if (!sign)
                                sign = ' ';
                        goto rflag;
                case '#':
                        flags |= ALT;
                        goto rflag;
                case '*':
                        /*
                         * ``A negative field width argument is taken as a
                         * - flag followed by a positive field width.''
                         *      -- ANSI X3J11
                         * They don't exclude field widths read from args.
                         */
                        if ((width = va_arg(ap, int)) >= 0)
                                goto rflag;
                        width = -width;
                        /* FALLTHROUGH */
                case '-':
                        flags |= LADJUST;
                        goto rflag;
                case '+':
                        sign = '+';
                        goto rflag;
                case '.':
                        if ((ch = *fmt++) == '*') {
                                n = va_arg(ap, int);
                                prec = n < 0 ? -1 : n;
                                goto rflag;
                        }
                        n = 0;
                        while (is_digit(ch)) {
                                n = 10 * n + to_digit(ch);
                                ch = *fmt++;
                        }
                        prec = n < 0 ? -1 : n;
                        goto reswitch;
                case '0':
                        /*
                         * ``Note that 0 is taken as a flag, not as the
                         * beginning of a field width.''
                         *      -- ANSI X3J11
                         */
                        flags |= ZEROPAD;
                        goto rflag;
                case '1': case '2': case '3': case '4':
                case '5': case '6': case '7': case '8': case '9':
                        n = 0;
                        do {
                                n = 10 * n + to_digit(ch);
                                ch = *fmt++;
                        } while (is_digit(ch));
                        width = n;
                        goto reswitch;
                case 'h':
                        flags |= SHORTINT;
                        goto rflag;
                case 'l':
                        if (*fmt == 'l') {
                                fmt++;
                                flags |= QUADINT;
                        } else {
                                flags |= LONGINT;
                        }
                        goto rflag;
                case 'q':
                        flags |= QUADINT;
                        goto rflag;
                case 'z':
                        flags |= SIZEINT;
                        goto rflag;
                case 'c':
                        *(cp = buf) = va_arg(ap, int);
                        size = 1;
                        sign = '\0';
                        break;
                case 't':
                        /* ptrdiff_t */
                        /* FALLTHROUGH */
                case 'D':
                        flags |= LONGINT;
                        /*FALLTHROUGH*/
                case 'd':
                case 'i':
                        _uquad = SARG();
                        if ((quad_t)_uquad < 0) {
                                _uquad = -_uquad;
                                sign = '-';
                        }
                        base = DEC;
                        goto number;
                case 'n':
                        panic("no %%n support");
                        break;
                case 'O':
                        flags |= LONGINT;
                        /*FALLTHROUGH*/
                case 'o':
                        _uquad = UARG();
                        base = OCT;
                        goto nosign;
                case 'p':
                        /*
                         * ``The argument shall be a pointer to void.  The
                         * value of the pointer is converted to a sequence
                         * of printable characters, in an implementation-
                         * defined manner.''
                         *      -- ANSI X3J11
                         */
                        _uquad = (u_long)va_arg(ap, void *);
                        base = HEX;
                        xdigs = "0123456789abcdef";
                        flags |= HEXPREFIX;
                        ch = 'x';
                        goto nosign;
                case 's':
                        if ((cp = va_arg(ap, char *)) == NULL)
                                cp = "(null)";
                        if (prec >= 0) {
                                /*
                                 * can't use strlen; can only look for the
                                 * NUL in the first `prec' characters, and
                                 * strlen() will go further.
                                 */
                                char *p = memchr(cp, 0, prec);

                                if (p != NULL) {
                                        size = p - cp;
                                        if (size > prec)
                                                size = prec;
                                } else
                                        size = prec;
                        } else
                                size = strlen(cp);
                        sign = '\0';
                        break;
                case 'U':
                        flags |= LONGINT;
                        /*FALLTHROUGH*/
                case 'u':
                        _uquad = UARG();
                        base = DEC;
                        goto nosign;
                case 'X':
                        xdigs = "0123456789ABCDEF";
                        goto hex;
                case 'x':
                        xdigs = "0123456789abcdef";
hex:                    _uquad = UARG();
                        base = HEX;
                        /* leading 0x/X only if non-zero */
                        if (flags & ALT && _uquad != 0)
                                flags |= HEXPREFIX;

                        /* unsigned conversions */
nosign:                 sign = '\0';
                        /*
                         * ``... diouXx conversions ... if a precision is
                         * specified, the 0 flag will be ignored.''
                         *      -- ANSI X3J11
                         */
number:                 if ((dprec = prec) >= 0)
                                flags &= ~ZEROPAD;

                        /*
                         * ``The result of converting a zero value with an
                         * explicit precision of zero is no characters.''
                         *      -- ANSI X3J11
                         */
                        cp = buf + KPRINTF_BUFSIZE;
                        if (_uquad != 0 || prec != 0) {
                                /*
                                 * Unsigned mod is hard, and unsigned mod
                                 * by a constant is easier than that by
                                 * a variable; hence this switch.
                                 */
                                switch (base) {
                                case OCT:
                                        do {
                                                *--cp = to_char(_uquad & 7);
                                                _uquad >>= 3;
                                        } while (_uquad);
                                        /* handle octal leading 0 */
                                        if (flags & ALT && *cp != '0')
                                                *--cp = '0';
                                        break;

                                case DEC:
                                        /* many numbers are 1 digit */
                                        while (_uquad >= 10) {
                                                *--cp = to_char(_uquad % 10);
                                                _uquad /= 10;
                                        }
                                        *--cp = to_char(_uquad);
                                        break;

                                case HEX:
                                        do {
                                                *--cp = xdigs[_uquad & 15];
                                                _uquad >>= 4;
                                        } while (_uquad);
                                        break;

                                default:
                                        cp = "bug in kprintf: bad base";
                                        size = strlen(cp);
                                        goto skipsize;
                                }
                        }
                        size = buf + KPRINTF_BUFSIZE - cp;
                skipsize:
                        break;
                default:        /* "%?" prints ?, unless ? is NUL */
                        if (ch == '\0')
                                goto done;
                        /* pretend it was %c with argument ch */
                        cp = buf;
                        *cp = ch;
                        size = 1;
                        sign = '\0';
                        break;
                }

                /*
                 * All reasonable formats wind up here.  At this point, `cp'
                 * points to a string which (if not flags&LADJUST) should be
                 * padded out to `width' places.  If flags&ZEROPAD, it should
                 * first be prefixed by any sign or other prefix; otherwise,
                 * it should be blank padded before the prefix is emitted.
                 * After any left-hand padding and prefixing, emit zeroes
                 * required by a decimal [diouxX] precision, then print the
                 * string proper, then emit zeroes required by any leftover
                 * floating precision; finally, if LADJUST, pad with blanks.
                 *
                 * Compute actual size, so we know how much to pad.
                 * size excludes decimal prec; realsz includes it.
                 */
                realsz = dprec > size ? dprec : size;
                if (sign)
                        realsz++;
                else if (flags & HEXPREFIX)
                        realsz+= 2;

                /* right-adjusting blank padding */
                if ((flags & (LADJUST|ZEROPAD)) == 0) {
                        n = width - realsz;
                        while (n-- > 0)
                                KPRINTF_PUTCHAR(' ');
                }

                /* prefix */
                if (sign) {
                        KPRINTF_PUTCHAR(sign);
                } else if (flags & HEXPREFIX) {
                        KPRINTF_PUTCHAR('0');
                        KPRINTF_PUTCHAR(ch);
                }

                /* right-adjusting zero padding */
                if ((flags & (LADJUST|ZEROPAD)) == ZEROPAD) {
                        n = width - realsz;
                        while (n-- > 0)
                                KPRINTF_PUTCHAR('0');
                }

                /* leading zeroes from decimal precision */
                n = dprec - size;
                while (n-- > 0)
                        KPRINTF_PUTCHAR('0');

                /* the string or number proper */
                while (size--)
                        KPRINTF_PUTCHAR(*cp++);
                /* left-adjusting padding (always blank) */
                if (flags & LADJUST) {
                        n = width - realsz;
                        while (n-- > 0)
                                KPRINTF_PUTCHAR(' ');
                }
        }

done:
        if ((oflags & TOBUFONLY) && (vp != NULL))
                *(char **)vp = sbuf;
overflow:
        return (ret);
        /* NOTREACHED */
}

#if __GNUC_PREREQ__(2,96)
/*
 * XXX - these functions shouldn't be in the kernel, but gcc 3.X feels like
 *       translating some printf calls to puts and since it doesn't seem
 *       possible to just turn off parts of those optimizations (some of
 *       them are really useful), we have to provide a dummy puts and putchar
 *       that are wrappers around printf.
 */
int     puts(const char *);
int     putchar(int c);

int
puts(const char *str)
{
        printf("%s\n", str);

        return (0);
}

int
putchar(int c)
{
        printf("%c", c);

        return (c);
}


#endif