sudo/compat/snprintf.c

/*
 * Copyright (c) 1999-2005, 2008, 2010
 *	Todd C. Miller <Todd.Miller@courtesan.com>
 * Copyright (c) 1990, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Chris Torek.
 *
 * 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.
 *
 * From: @(#)vfprintf.c	8.1 (Berkeley) 6/4/93
 */

/*
 * v?snprintf/v?asprintf based on 4.4BSD stdio.
 * NOTE: does not support floating point.
 */

#include <config.h>

#include <sys/types.h>
#include <sys/param.h>

#include <stdio.h>
#ifdef STDC_HEADERS
# include <stdlib.h>
# include <stddef.h>
#else
# ifdef HAVE_STDLIB_H
#  include <stdlib.h>
# endif
#endif /* STDC_HEADERS */
#ifdef HAVE_STDINT_H
# include <stdint.h>
#endif
#ifdef HAVE_STRING_H
# if defined(HAVE_MEMORY_H) && !defined(STDC_HEADERS)
#  include <memory.h>
# endif
# include <string.h>
#endif /* HAVE_STRING_H */
#ifdef HAVE_STRINGS_H
# include <strings.h>
#endif /* HAVE_STRINGS_H */
#if defined(HAVE_MALLOC_H) && !defined(STDC_HEADERS)
# include <malloc.h>
#endif /* HAVE_MALLOC_H && !STDC_HEADERS */
#include <limits.h>
#include <stdarg.h>

#include "missing.h"

static int xxxprintf(char **, size_t, int, const char *, va_list);

/*
 * Some systems may not have these defined in <limits.h>
 */
#ifndef ULONG_MAX
# define ULONG_MAX	((unsigned long)-1)
#endif
#ifndef LONG_MAX
# define LONG_MAX	(ULONG_MAX / 2)
#endif
#ifdef HAVE_LONG_LONG_INT
# ifndef ULLONG_MAX
#  ifdef UQUAD_MAX
#   define ULLONG_MAX	UQUAD_MAX
#  else
#   define ULLONG_MAX	((unsigned long long)-1)
#  endif
# endif
# ifndef LLONG_MAX
#  ifdef QUAD_MAX
#   define LLONG_MAX	QUAD_MAX
#  else
#   define LLONG_MAX	(ULLONG_MAX / 2)
#  endif
# endif
#endif /* HAVE_LONG_LONG_INT */

/*
 * Macros for converting digits to letters and vice versa
 */
#define	to_digit(c)	((c) - '0')
#define is_digit(c)	((unsigned int)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 BUF		68

/*
 * Convert an unsigned long to ASCII for printf purposes, returning
 * a pointer to the first character of the string representation.
 * Octal numbers can be forced to have a leading zero; hex numbers
 * use the given digits.
 */
static char *
__ultoa(unsigned long val, char *endp, int base, int octzero, char *xdigs)
{
	char *cp = endp;
	long sval;

	/*
	 * Handle the three cases separately, in the hope of getting
	 * better/faster code.
	 */
	switch (base) {
	case 10:
		if (val < 10) {	/* many numbers are 1 digit */
			*--cp = to_char(val);
			return (cp);
		}
		/*
		 * On many machines, unsigned arithmetic is harder than
		 * signed arithmetic, so we do at most one unsigned mod and
		 * divide; this is sufficient to reduce the range of
		 * the incoming value to where signed arithmetic works.
		 */
		if (val > LONG_MAX) {
			*--cp = to_char(val % 10);
			sval = val / 10;
		} else
			sval = val;
		do {
			*--cp = to_char(sval % 10);
			sval /= 10;
		} while (sval != 0);
		break;

	case 8:
		do {
			*--cp = to_char(val & 7);
			val >>= 3;
		} while (val);
		if (octzero && *cp != '0')
			*--cp = '0';
		break;

	case 16:
		do {
			*--cp = xdigs[val & 15];
			val >>= 4;
		} while (val);
		break;

	default:			/* oops */
		abort();
	}
	return (cp);
}

/* Identical to __ultoa, but for quads. */
#ifdef HAVE_LONG_LONG_INT
# if SIZEOF_LONG_INT == 8
#  define __uqtoa(v, e, b, o, x) __ultoa((unsigned long)(v), (e), (b), (o), (x))
# else
static char *
__uqtoa(unsigned long long val, char *endp, int base, int octzero, char *xdigs)
{
	char *cp = endp;
	long long sval;

	/* quick test for small values; __ultoa is typically much faster */
	/* (perhaps instead we should run until small, then call __ultoa?) */
	if (val <= (unsigned long long)ULONG_MAX)
		return (__ultoa((unsigned long)val, endp, base, octzero, xdigs));
	switch (base) {
	case 10:
		if (val < 10) {
			*--cp = to_char(val % 10);
			return (cp);
		}
		if (val > LLONG_MAX) {
			*--cp = to_char(val % 10);
			sval = val / 10;
		} else
			sval = val;
		do {
			*--cp = to_char(sval % 10);
			sval /= 10;
		} while (sval != 0);
		break;

	case 8:
		do {
			*--cp = to_char(val & 7);
			val >>= 3;
		} while (val);
		if (octzero && *cp != '0')
			*--cp = '0';
		break;

	case 16:
		do {
			*--cp = xdigs[val & 15];
			val >>= 4;
		} while (val);
		break;

	default:			/* oops */
		abort();
	}
	return (cp);
}
# endif /* !SIZEOF_LONG_INT */
#endif /* HAVE_LONG_LONG_INT */

/*
 * Actual printf innards.
 */
static int
xxxprintf(char **strp, size_t strsize, int alloc, const char *fmt0, va_list ap)
{
	char *fmt;		/* format string */
	int ch;			/* character from fmt */
	int n;			/* handy integer (short term usage) */
	char *cp;		/* 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) */
	unsigned long ulval;	/* integer arguments %[diouxX] */
#ifdef HAVE_LONG_LONG_INT
	unsigned long long uqval; /* %q (quad) integers */
#endif
	int base;		/* base for [diouxX] conversion */
	int dprec;		/* a copy of prec if [diouxX], 0 otherwise */
	int fieldsz;		/* field size expanded by sign, etc */
	int realsz;		/* field size expanded by dprec */
	int size;		/* size of converted field or string */
	char *xdigs;		/* digits for [xX] conversion */
	char buf[BUF];		/* space for %c, %[diouxX], %[eEfgG] */
	char ox[2];		/* space for 0x hex-prefix */
	char *str;		/* pointer to string to fill */
	char *estr;		/* pointer to last char in str */

	/*
	 * Choose PADSIZE to trade efficiency vs. size.  If larger printf
	 * fields occur frequently, increase PADSIZE and make the initialisers
	 * below longer.
	 */
#define	PADSIZE	16		/* pad chunk size */
	static char blanks[PADSIZE] =
	 {' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' '};
	static char zeroes[PADSIZE] =
	 {'0','0','0','0','0','0','0','0','0','0','0','0','0','0','0','0'};

	/* Print chars to "str", (allocate as needed if alloc is set). */
#define	PRINT(ptr, len) do { \
	const char *p = ptr; \
	const char *endp = ptr + len; \
	while (p < endp && (str < estr || alloc)) { \
		if (alloc && str >= estr) { \
			char *t; \
			strsize = (strsize << 1) + 1; \
			if (!(t = (char *)realloc(*strp, strsize))) { \
				free(str); \
				*strp = NULL; \
				ret = -1; \
				goto done; \
			} \
			str = t + (str - *strp); \
			estr = t + strsize - 1; \
			*strp = t; \
		} \
		*str++ = *p++; \
	} \
} while (0)

	/* BEWARE, PAD uses `n'. */
#define	PAD(howmany, with) do { \
	if ((n = (howmany)) > 0) { \
		while (n > PADSIZE) { \
			PRINT(with, PADSIZE); \
			n -= PADSIZE; \
		} \
		PRINT(with, n); \
	} \
} while (0)

	/*
	 * To extend shorts properly, we need both signed and unsigned
	 * argument extraction methods.
	 */
#define	SARG() \
	(flags&LONGINT ? va_arg(ap, long) : \
	    flags&SHORTINT ? (long)(short)va_arg(ap, int) : \
	    (long)va_arg(ap, int))
#define	UARG() \
	(flags&LONGINT ? va_arg(ap, unsigned long) : \
	    flags&SHORTINT ? (unsigned long)(unsigned short)va_arg(ap, int) : \
	    (unsigned long)va_arg(ap, unsigned int))

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

	if (alloc) {
		strsize = 128;
		*strp = str = (char *)malloc(strsize);
		if (str == NULL) {
			ret = -1;
			goto done;
		}
		estr = str + 127;
	} else {
		str = *strp;
		if (strsize)
			estr = str + strsize - 1;
		else
			estr = NULL;
	}

	/*
	 * Scan the format for conversions (`%' character).
	 */
	for (;;) {
		for (cp = fmt; (ch = *fmt) != '\0' && ch != '%'; fmt++)
			/* void */;
		if ((n = fmt - cp) != 0) {
			PRINT(cp, n);
			ret += n;
		}
		if (ch == '\0')
			goto done;
		fmt++;		/* skip over '%' */

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

rflag:		ch = *fmt++;
reswitch:	switch (ch) {
		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':
			flags |= LONGINT;
			goto rflag;
#ifdef HAVE_LONG_LONG_INT
		case 'q':
			flags |= QUADINT;
			goto rflag;
#endif /* HAVE_LONG_LONG_INT */
		case 'c':
			*(cp = buf) = va_arg(ap, int);
			size = 1;
			sign = '\0';
			break;
		case 'D':
			flags |= LONGINT;
			/*FALLTHROUGH*/
		case 'd':
		case 'i':
#ifdef HAVE_LONG_LONG_INT
			if (flags & QUADINT) {
				uqval = va_arg(ap, long long);
				if ((long long)uqval < 0) {
					uqval = -uqval;
					sign = '-';
				}
			}
			else
#endif /* HAVE_LONG_LONG_INT */
			{
				ulval = SARG();
				if ((long)ulval < 0) {
					ulval = -ulval;
					sign = '-';
				}
			}
			base = 10;
			goto number;
		case 'n':
#ifdef HAVE_LONG_LONG_INT
			if (flags & QUADINT)
				*va_arg(ap, long long *) = ret;
			else
#endif /* HAVE_LONG_LONG_INT */
			if (flags & LONGINT)
				*va_arg(ap, long *) = ret;
			else if (flags & SHORTINT)
				*va_arg(ap, short *) = ret;
			else
				*va_arg(ap, int *) = ret;
			continue;	/* no output */
		case 'O':
			flags |= LONGINT;
			/*FALLTHROUGH*/
		case 'o':
#ifdef HAVE_LONG_LONG_INT
			if (flags & QUADINT)
				uqval = va_arg(ap, unsigned long long);
			else
#endif /* HAVE_LONG_LONG_INT */
				ulval = UARG();
			base = 8;
			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
			 */
			ulval = (unsigned long)va_arg(ap, void *);
			base = 16;
			xdigs = "0123456789abcdef";
			flags = (flags & ~QUADINT) | 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':
#ifdef HAVE_LONG_LONG_INT
			if (flags & QUADINT)
				uqval = va_arg(ap, unsigned long long);
			else
#endif /* HAVE_LONG_LONG_INT */
				ulval = UARG();
			base = 10;
			goto nosign;
		case 'X':
			xdigs = "0123456789ABCDEF";
			goto hex;
		case 'x':
			xdigs = "0123456789abcdef";
hex:
#ifdef HAVE_LONG_LONG_INT
			if (flags & QUADINT)
				uqval = va_arg(ap, unsigned long long);
			else
#endif /* HAVE_LONG_LONG_INT */
				ulval = UARG();
			base = 16;
			/* leading 0x/X only if non-zero */
			if (flags & ALT &&
#ifdef HAVE_LONG_LONG_INT
			    (flags & QUADINT ? uqval != 0 : ulval != 0))
#else
			    ulval != 0)
#endif /* HAVE_LONG_LONG_INT */
				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 + BUF;
#ifdef HAVE_LONG_LONG_INT
			if (flags & QUADINT) {
				if (uqval != 0 || prec != 0)
					cp = __uqtoa(uqval, cp, base,
					    flags & ALT, xdigs);
			}
			else
#endif /* HAVE_LONG_LONG_INT */
			{
				if (ulval != 0 || prec != 0)
					cp = __ultoa(ulval, cp, base,
					    flags & ALT, xdigs);
			}
			size = buf + BUF - cp;
			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.
		 * fieldsz excludes decimal prec; realsz includes it.
		 */
		fieldsz = size;
		if (sign)
			fieldsz++;
		else if (flags & HEXPREFIX)
			fieldsz += 2;
		realsz = dprec > fieldsz ? dprec : fieldsz;

		/* right-adjusting blank padding */
		if ((flags & (LADJUST|ZEROPAD)) == 0)
			PAD(width - realsz, blanks);

		/* prefix */
		if (sign) {
			PRINT(&sign, 1);
		} else if (flags & HEXPREFIX) {
			ox[0] = '0';
			ox[1] = ch;
			PRINT(ox, 2);
		}

		/* right-adjusting zero padding */
		if ((flags & (LADJUST|ZEROPAD)) == ZEROPAD)
			PAD(width - realsz, zeroes);

		/* leading zeroes from decimal precision */
		PAD(dprec - fieldsz, zeroes);

		/* the string or number proper */
		PRINT(cp, size);

		/* left-adjusting padding (always blank) */
		if (flags & LADJUST)
			PAD(width - realsz, blanks);

		/* finally, adjust ret */
		ret += width > realsz ? width : realsz;
	}
done:
	if (strsize)
		*str = '\0';
	return (ret);
	/* NOTREACHED */
}

#ifndef HAVE_VSNPRINTF
int
vsnprintf(char *str, size_t n, const char *fmt, va_list ap)
{

	return (xxxprintf(&str, n, 0, fmt, ap));
}
#endif /* HAVE_VSNPRINTF */

#ifndef HAVE_SNPRINTF
int
snprintf(char *str, size_t n, char const *fmt, ...)
{
	int ret;
	va_list ap;

	va_start(ap, fmt);
	ret = xxxprintf(&str, n, 0, fmt, ap);
	va_end(ap);
	return (ret);
}
#endif /* HAVE_SNPRINTF */

#ifndef HAVE_VASPRINTF
int
vasprintf(char **str, const char *fmt, va_list ap)
{

	return (xxxprintf(str, 0, 1, fmt, ap));
}
#endif /* HAVE_VASPRINTF */

#ifndef HAVE_ASPRINTF
int
asprintf(char **str, char const *fmt, ...)
{
	int ret;
	va_list ap;

	va_start(ap, fmt);
	ret = xxxprintf(str, 0, 1, fmt, ap);
	va_end(ap);
	return (ret);
}
#endif /* HAVE_ASPRINTF */