vfscanf.c

在x86平台上运行不可信任代码的sandbox。

/*-
 * 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 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.
 */

#define FLOATING_POINT 1

#if defined(LIBC_SCCS) && !defined(lint)
static char rcsid[] = "$OpenBSD: vfscanf.c,v 1.6 1998/01/20 21:25:39 millert Exp $";
#endif /* LIBC_SCCS and not lint */

#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#ifdef __STDC__
#include <stdarg.h>
#else
#include <varargs.h>
#endif
#include "local.h"

#define FLOATING_POINT 1

#ifdef FLOATING_POINT
#include "floatio.h"
#endif

#define	BUF		513	/* Maximum length of numeric string. */

/*
 * Flags used during conversion.
 */
#define	LONG		0x01	/* l: long or double */
#define	LONGDBL		0x02	/* L: long double; unimplemented */
#define	SHORT		0x04	/* h: short */
#define QUAD		0x08	/* q: quad */
#define	SUPPRESS	0x10	/* suppress assignment */
#define	POINTER		0x20	/* weird %p pointer (`fake hex') */
#define	NOSKIP		0x40	/* do not skip blanks */

/*
 * The following are used in numeric conversions only:
 * SIGNOK, NDIGITS, DPTOK, and EXPOK are for floating point;
 * SIGNOK, NDIGITS, PFXOK, and NZDIGITS are for integral.
 */
#define	SIGNOK		0x080	/* +/- is (still) legal */
#define	NDIGITS		0x100	/* no digits detected */

#define	DPTOK		0x200	/* (float) decimal point is still legal */
#define	EXPOK		0x400	/* (float) exponent (e+3, etc) still legal */

#define	PFXOK		0x200	/* 0x prefix is (still) legal */
#define	NZDIGITS	0x400	/* no zero digits detected */

/*
 * Conversion types.
 */
#define	CT_CHAR		0	/* %c conversion */
#define	CT_CCL		1	/* %[...] conversion */
#define	CT_STRING	2	/* %s conversion */
#define	CT_INT		3	/* integer, i.e., strtoq or strtouq */
#define	CT_FLOAT	4	/* floating, i.e., strtod */

#define u_char unsigned char
#define u_long unsigned long

static u_char *__sccl();

/*
 * vfscanf
 */
int
__svfscanf(fp, fmt0, ap)
	register FILE *fp;
	char const *fmt0;
	_BSD_VA_LIST_ ap;
{
	register u_char *fmt = (u_char *)fmt0;
	register int c;		/* character from format, or conversion */
	register size_t width;	/* field width, or 0 */
	register char *p;	/* points into all kinds of strings */
	register int n;		/* handy integer */
	register int flags;	/* flags as defined above */
	register char *p0;	/* saves original value of p when necessary */
	int nassigned;		/* number of fields assigned */
	int nread;		/* number of characters consumed from fp */
	int base;		/* base argument to strtoq/strtouq */
	u_quad_t (*ccfn)();	/* conversion function (strtoq/strtouq) */
	char ccltab[256];	/* character class table for %[...] */
	char buf[BUF];		/* buffer for numeric conversions */

	/* `basefix' is used to avoid `if' tests in the integer scanner */
	static short basefix[17] =
		{ 10, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 };

	nassigned = 0;
	nread = 0;
	base = 0;		/* XXX just to keep gcc happy */
	ccfn = NULL;		/* XXX just to keep gcc happy */
	for (;;) {
		c = *fmt++;
		if (c == 0)
			return (nassigned);
		if (isspace(c)) {
			while ((fp->_r > 0 || __srefill(fp) == 0) &&
			    isspace(*fp->_p))
				nread++, fp->_r--, fp->_p++;
			continue;
		}
		if (c != '%')
			goto literal;
		width = 0;
		flags = 0;
		/*
		 * switch on the format.  continue if done;
		 * break once format type is derived.
		 */
again:		c = *fmt++;
		switch (c) {
		case '%':
literal:
			if (fp->_r <= 0 && __srefill(fp))
				goto input_failure;
			if (*fp->_p != c)
				goto match_failure;
			fp->_r--, fp->_p++;
			nread++;
			continue;

		case '*':
			flags |= SUPPRESS;
			goto again;
		case 'L':
			flags |= LONGDBL;
			goto again;
		case 'h':
			flags |= SHORT;
			goto again;
		case 'l':
			if (*fmt == 'l') {
				fmt++;
				flags |= QUAD;
			} else {
				flags |= LONG;
			}
			goto again;
		case 'q':
			flags |= QUAD;
			goto again;

		case '0': case '1': case '2': case '3': case '4':
		case '5': case '6': case '7': case '8': case '9':
			width = width * 10 + c - '0';
			goto again;

		/*
		 * Conversions.
		 * Those marked `compat' are for 4.[123]BSD compatibility.
		 *
		 * (According to ANSI, E and X formats are supposed
		 * to the same as e and x.  Sorry about that.)
		 */
		case 'D':	/* compat */
			flags |= LONG;
			/* FALLTHROUGH */
		case 'd':
			c = CT_INT;
			ccfn = (u_quad_t (*)())strtoq;
			base = 10;
			break;

		case 'i':
			c = CT_INT;
			ccfn = (u_quad_t (*)())strtoq;
			base = 0;
			break;

		case 'O':	/* compat */
			flags |= LONG;
			/* FALLTHROUGH */
		case 'o':
			c = CT_INT;
			ccfn = strtouq;
			base = 8;
			break;

		case 'u':
			c = CT_INT;
			ccfn = strtouq;
			base = 10;
			break;

		case 'X':
		case 'x':
			flags |= PFXOK;	/* enable 0x prefixing */
			c = CT_INT;
			ccfn = strtouq;
			base = 16;
			break;

#ifdef FLOATING_POINT
		case 'E':
		case 'G':
		case 'e': 
		case 'f': 
		case 'g':
			c = CT_FLOAT;
			break;
#endif

		case 's':
			c = CT_STRING;
			break;

		case '[':
			fmt = __sccl(ccltab, fmt);
			flags |= NOSKIP;
			c = CT_CCL;
			break;

		case 'c':
			flags |= NOSKIP;
			c = CT_CHAR;
			break;

		case 'p':	/* pointer format is like hex */
			flags |= POINTER | PFXOK;
			c = CT_INT;
			ccfn = strtouq;
			base = 16;
			break;

		case 'n':
			if (flags & SUPPRESS)	/* ??? */
				continue;
			if (flags & SHORT)
				*va_arg(ap, short *) = nread;
			else if (flags & LONG)
				*va_arg(ap, long *) = nread;
			else
				*va_arg(ap, int *) = nread;
			continue;

		/*
		 * Disgusting backwards compatibility hacks.	XXX
		 */
		case '\0':	/* compat */
			return (EOF);

		default:	/* compat */
			if (isupper(c))
				flags |= LONG;
			c = CT_INT;
			ccfn = (u_quad_t (*)())strtoq;
			base = 10;
			break;
		}

		/*
		 * We have a conversion that requires input.
		 */
		if (fp->_r <= 0 && __srefill(fp))
			goto input_failure;

		/*
		 * Consume leading white space, except for formats
		 * that suppress this.
		 */
		if ((flags & NOSKIP) == 0) {
			while (isspace(*fp->_p)) {
				nread++;
				if (--fp->_r > 0)
					fp->_p++;
				else if (__srefill(fp))
					goto input_failure;
			}
			/*
			 * Note that there is at least one character in
			 * the buffer, so conversions that do not set NOSKIP
			 * ca no longer result in an input failure.
			 */
		}

		/*
		 * Do the conversion.
		 */
		switch (c) {

		case CT_CHAR:
			/* scan arbitrary characters (sets NOSKIP) */
			if (width == 0)
				width = 1;
			if (flags & SUPPRESS) {
				size_t sum = 0;
				for (;;) {
					if ((n = fp->_r) < width) {
						sum += n;
						width -= n;
						fp->_p += n;
						if (__srefill(fp)) {
							if (sum == 0)
							    goto input_failure;
							break;
						}
					} else {
						sum += width;
						fp->_r -= width;
						fp->_p += width;
						break;
					}
				}
				nread += sum;
			} else {
				size_t r = fread((void *)va_arg(ap, char *), 1,
				    width, fp);

				if (r == 0)
					goto input_failure;
				nread += r;
				nassigned++;
			}
			break;

		case CT_CCL:
			/* scan a (nonempty) character class (sets NOSKIP) */
			if (width == 0)
				width = (size_t)~0;	/* `infinity' */
			/* take only those things in the class */
			if (flags & SUPPRESS) {
				n = 0;
				while (ccltab[*fp->_p]) {
					n++, fp->_r--, fp->_p++;
					if (--width == 0)
						break;
					if (fp->_r <= 0 && __srefill(fp)) {
						if (n == 0)
							goto input_failure;
						break;
					}
				}
				if (n == 0)
					goto match_failure;
			} else {
				p0 = p = va_arg(ap, char *);
				while (ccltab[*fp->_p]) {
					fp->_r--;
					*p++ = *fp->_p++;
					if (--width == 0)
						break;
					if (fp->_r <= 0 && __srefill(fp)) {
						if (p == p0)