subr_scanf.c revision 127911 
1/*-
2 * Copyright (c) 1990, 1993
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * Chris Torek.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 * 4. Neither the name of the University nor the names of its contributors
17 *    may be used to endorse or promote products derived from this software
18 *    without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 *
32 * From: Id: vfscanf.c,v 1.13 1998/09/25 12:20:27 obrien Exp
33 * From: static char sccsid[] = "@(#)strtol.c	8.1 (Berkeley) 6/4/93";
34 * From: static char sccsid[] = "@(#)strtoul.c	8.1 (Berkeley) 6/4/93";
35 */
36
37#include <sys/cdefs.h>
38__FBSDID("$FreeBSD: head/sys/kern/subr_scanf.c 127911 2004-04-05 21:03:37Z imp $");
39
40#include <sys/param.h>
41#include <sys/systm.h>
42#include <sys/ctype.h>
43#include <sys/limits.h>
44
45/*
46 * Note that stdarg.h and the ANSI style va_start macro is used for both
47 * ANSI and traditional C compilers.
48 */
49#include <machine/stdarg.h>
50
51#define	BUF		32 	/* Maximum length of numeric string. */
52
53/*
54 * Flags used during conversion.
55 */
56#define	LONG		0x01	/* l: long or double */
57#define	SHORT		0x04	/* h: short */
58#define	SUPPRESS	0x08	/* suppress assignment */
59#define	POINTER		0x10	/* weird %p pointer (`fake hex') */
60#define	NOSKIP		0x20	/* do not skip blanks */
61#define	QUAD		0x400
62
63/*
64 * The following are used in numeric conversions only:
65 * SIGNOK, NDIGITS, DPTOK, and EXPOK are for floating point;
66 * SIGNOK, NDIGITS, PFXOK, and NZDIGITS are for integral.
67 */
68#define	SIGNOK		0x40	/* +/- is (still) legal */
69#define	NDIGITS		0x80	/* no digits detected */
70
71#define	DPTOK		0x100	/* (float) decimal point is still legal */
72#define	EXPOK		0x200	/* (float) exponent (e+3, etc) still legal */
73
74#define	PFXOK		0x100	/* 0x prefix is (still) legal */
75#define	NZDIGITS	0x200	/* no zero digits detected */
76
77/*
78 * Conversion types.
79 */
80#define	CT_CHAR		0	/* %c conversion */
81#define	CT_CCL		1	/* %[...] conversion */
82#define	CT_STRING	2	/* %s conversion */
83#define	CT_INT		3	/* integer, i.e., strtoq or strtouq */
84typedef u_quad_t (*ccfntype)(const char *, char **, int);
85
86static const u_char *__sccl(char *, const u_char *);
87
88int
89sscanf(const char *ibuf, const char *fmt, ...)
90{
91	va_list ap;
92	int ret;
93
94	va_start(ap, fmt);
95	ret = vsscanf(ibuf, fmt, ap);
96	va_end(ap);
97	return(ret);
98}
99
100int
101vsscanf(const char *inp, char const *fmt0, va_list ap)
102{
103	int inr;
104	const u_char *fmt = (const u_char *)fmt0;
105	int c;			/* character from format, or conversion */
106	size_t width;		/* field width, or 0 */
107	char *p;		/* points into all kinds of strings */
108	int n;			/* handy integer */
109	int flags;		/* flags as defined above */
110	char *p0;		/* saves original value of p when necessary */
111	int nassigned;		/* number of fields assigned */
112	int nconversions;	/* number of conversions */
113	int nread;		/* number of characters consumed from fp */
114	int base;		/* base argument to strtoq/strtouq */
115	ccfntype ccfn;		/* conversion function (strtoq/strtouq) */
116	char ccltab[256];	/* character class table for %[...] */
117	char buf[BUF];		/* buffer for numeric conversions */
118
119	/* `basefix' is used to avoid `if' tests in the integer scanner */
120	static short basefix[17] =
121		{ 10, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 };
122
123	inr = strlen(inp);
124
125	nassigned = 0;
126	nconversions = 0;
127	nread = 0;
128	base = 0;		/* XXX just to keep gcc happy */
129	ccfn = NULL;		/* XXX just to keep gcc happy */
130	for (;;) {
131		c = *fmt++;
132		if (c == 0)
133			return (nassigned);
134		if (isspace(c)) {
135			while (inr > 0 && isspace(*inp))
136				nread++, inr--, inp++;
137			continue;
138		}
139		if (c != '%')
140			goto literal;
141		width = 0;
142		flags = 0;
143		/*
144		 * switch on the format.  continue if done;
145		 * break once format type is derived.
146		 */
147again:		c = *fmt++;
148		switch (c) {
149		case '%':
150literal:
151			if (inr <= 0)
152				goto input_failure;
153			if (*inp != c)
154				goto match_failure;
155			inr--, inp++;
156			nread++;
157			continue;
158
159		case '*':
160			flags |= SUPPRESS;
161			goto again;
162		case 'l':
163			flags |= LONG;
164			goto again;
165		case 'q':
166			flags |= QUAD;
167			goto again;
168		case 'h':
169			flags |= SHORT;
170			goto again;
171
172		case '0': case '1': case '2': case '3': case '4':
173		case '5': case '6': case '7': case '8': case '9':
174			width = width * 10 + c - '0';
175			goto again;
176
177		/*
178		 * Conversions.
179		 *
180		 */
181		case 'd':
182			c = CT_INT;
183			ccfn = (ccfntype)strtoq;
184			base = 10;
185			break;
186
187		case 'i':
188			c = CT_INT;
189			ccfn = (ccfntype)strtoq;
190			base = 0;
191			break;
192
193		case 'o':
194			c = CT_INT;
195			ccfn = strtouq;
196			base = 8;
197			break;
198
199		case 'u':
200			c = CT_INT;
201			ccfn = strtouq;
202			base = 10;
203			break;
204
205		case 'x':
206			flags |= PFXOK;	/* enable 0x prefixing */
207			c = CT_INT;
208			ccfn = strtouq;
209			base = 16;
210			break;
211
212		case 's':
213			c = CT_STRING;
214			break;
215
216		case '[':
217			fmt = __sccl(ccltab, fmt);
218			flags |= NOSKIP;
219			c = CT_CCL;
220			break;
221
222		case 'c':
223			flags |= NOSKIP;
224			c = CT_CHAR;
225			break;
226
227		case 'p':	/* pointer format is like hex */
228			flags |= POINTER | PFXOK;
229			c = CT_INT;
230			ccfn = strtouq;
231			base = 16;
232			break;
233
234		case 'n':
235			nconversions++;
236			if (flags & SUPPRESS)	/* ??? */
237				continue;
238			if (flags & SHORT)
239				*va_arg(ap, short *) = nread;
240			else if (flags & LONG)
241				*va_arg(ap, long *) = nread;
242			else if (flags & QUAD)
243				*va_arg(ap, quad_t *) = nread;
244			else
245				*va_arg(ap, int *) = nread;
246			continue;
247		}
248
249		/*
250		 * We have a conversion that requires input.
251		 */
252		if (inr <= 0)
253			goto input_failure;
254
255		/*
256		 * Consume leading white space, except for formats
257		 * that suppress this.
258		 */
259		if ((flags & NOSKIP) == 0) {
260			while (isspace(*inp)) {
261				nread++;
262				if (--inr > 0)
263					inp++;
264				else
265					goto input_failure;
266			}
267			/*
268			 * Note that there is at least one character in
269			 * the buffer, so conversions that do not set NOSKIP
270			 * can no longer result in an input failure.
271			 */
272		}
273
274		/*
275		 * Do the conversion.
276		 */
277		switch (c) {
278
279		case CT_CHAR:
280			/* scan arbitrary characters (sets NOSKIP) */
281			if (width == 0)
282				width = 1;
283			if (flags & SUPPRESS) {
284				size_t sum = 0;
285				for (;;) {
286					if ((n = inr) < width) {
287						sum += n;
288						width -= n;
289						inp += n;
290						if (sum == 0)
291							goto input_failure;
292						break;
293					} else {
294						sum += width;
295						inr -= width;
296						inp += width;
297						break;
298					}
299				}
300				nread += sum;
301			} else {
302				bcopy(inp, va_arg(ap, char *), width);
303				inr -= width;
304				inp += width;
305				nread += width;
306				nassigned++;
307			}
308			nconversions++;
309			break;
310
311		case CT_CCL:
312			/* scan a (nonempty) character class (sets NOSKIP) */
313			if (width == 0)
314				width = (size_t)~0;	/* `infinity' */
315			/* take only those things in the class */
316			if (flags & SUPPRESS) {
317				n = 0;
318				while (ccltab[(unsigned char)*inp]) {
319					n++, inr--, inp++;
320					if (--width == 0)
321						break;
322					if (inr <= 0) {
323						if (n == 0)
324							goto input_failure;
325						break;
326					}
327				}
328				if (n == 0)
329					goto match_failure;
330			} else {
331				p0 = p = va_arg(ap, char *);
332				while (ccltab[(unsigned char)*inp]) {
333					inr--;
334					*p++ = *inp++;
335					if (--width == 0)
336						break;
337					if (inr <= 0) {
338						if (p == p0)
339							goto input_failure;
340						break;
341					}
342				}
343				n = p - p0;
344				if (n == 0)
345					goto match_failure;
346				*p = 0;
347				nassigned++;
348			}
349			nread += n;
350			nconversions++;
351			break;
352
353		case CT_STRING:
354			/* like CCL, but zero-length string OK, & no NOSKIP */
355			if (width == 0)
356				width = (size_t)~0;
357			if (flags & SUPPRESS) {
358				n = 0;
359				while (!isspace(*inp)) {
360					n++, inr--, inp++;
361					if (--width == 0)
362						break;
363					if (inr <= 0)
364						break;
365				}
366				nread += n;
367			} else {
368				p0 = p = va_arg(ap, char *);
369				while (!isspace(*inp)) {
370					inr--;
371					*p++ = *inp++;
372					if (--width == 0)
373						break;
374					if (inr <= 0)
375						break;
376				}
377				*p = 0;
378				nread += p - p0;
379				nassigned++;
380			}
381			nconversions++;
382			continue;
383
384		case CT_INT:
385			/* scan an integer as if by strtoq/strtouq */
386#ifdef hardway
387			if (width == 0 || width > sizeof(buf) - 1)
388				width = sizeof(buf) - 1;
389#else
390			/* size_t is unsigned, hence this optimisation */
391			if (--width > sizeof(buf) - 2)
392				width = sizeof(buf) - 2;
393			width++;
394#endif
395			flags |= SIGNOK | NDIGITS | NZDIGITS;
396			for (p = buf; width; width--) {
397				c = *inp;
398				/*
399				 * Switch on the character; `goto ok'
400				 * if we accept it as a part of number.
401				 */
402				switch (c) {
403
404				/*
405				 * The digit 0 is always legal, but is
406				 * special.  For %i conversions, if no
407				 * digits (zero or nonzero) have been
408				 * scanned (only signs), we will have
409				 * base==0.  In that case, we should set
410				 * it to 8 and enable 0x prefixing.
411				 * Also, if we have not scanned zero digits
412				 * before this, do not turn off prefixing
413				 * (someone else will turn it off if we
414				 * have scanned any nonzero digits).
415				 */
416				case '0':
417					if (base == 0) {
418						base = 8;
419						flags |= PFXOK;
420					}
421					if (flags & NZDIGITS)
422					    flags &= ~(SIGNOK|NZDIGITS|NDIGITS);
423					else
424					    flags &= ~(SIGNOK|PFXOK|NDIGITS);
425					goto ok;
426
427				/* 1 through 7 always legal */
428				case '1': case '2': case '3':
429				case '4': case '5': case '6': case '7':
430					base = basefix[base];
431					flags &= ~(SIGNOK | PFXOK | NDIGITS);
432					goto ok;
433
434				/* digits 8 and 9 ok iff decimal or hex */
435				case '8': case '9':
436					base = basefix[base];
437					if (base <= 8)
438						break;	/* not legal here */
439					flags &= ~(SIGNOK | PFXOK | NDIGITS);
440					goto ok;
441
442				/* letters ok iff hex */
443				case 'A': case 'B': case 'C':
444				case 'D': case 'E': case 'F':
445				case 'a': case 'b': case 'c':
446				case 'd': case 'e': case 'f':
447					/* no need to fix base here */
448					if (base <= 10)
449						break;	/* not legal here */
450					flags &= ~(SIGNOK | PFXOK | NDIGITS);
451					goto ok;
452
453				/* sign ok only as first character */
454				case '+': case '-':
455					if (flags & SIGNOK) {
456						flags &= ~SIGNOK;
457						goto ok;
458					}
459					break;
460
461				/* x ok iff flag still set & 2nd char */
462				case 'x': case 'X':
463					if (flags & PFXOK && p == buf + 1) {
464						base = 16;	/* if %i */
465						flags &= ~PFXOK;
466						goto ok;
467					}
468					break;
469				}
470
471				/*
472				 * If we got here, c is not a legal character
473				 * for a number.  Stop accumulating digits.
474				 */
475				break;
476		ok:
477				/*
478				 * c is legal: store it and look at the next.
479				 */
480				*p++ = c;
481				if (--inr > 0)
482					inp++;
483				else
484					break;		/* end of input */
485			}
486			/*
487			 * If we had only a sign, it is no good; push
488			 * back the sign.  If the number ends in `x',
489			 * it was [sign] '0' 'x', so push back the x
490			 * and treat it as [sign] '0'.
491			 */
492			if (flags & NDIGITS) {
493				if (p > buf) {
494					inp--;
495					inr++;
496				}
497				goto match_failure;
498			}
499			c = ((u_char *)p)[-1];
500			if (c == 'x' || c == 'X') {
501				--p;
502				inp--;
503				inr++;
504			}
505			if ((flags & SUPPRESS) == 0) {
506				u_quad_t res;
507
508				*p = 0;
509				res = (*ccfn)(buf, (char **)NULL, base);
510				if (flags & POINTER)
511					*va_arg(ap, void **) =
512						(void *)(uintptr_t)res;
513				else if (flags & SHORT)
514					*va_arg(ap, short *) = res;
515				else if (flags & LONG)
516					*va_arg(ap, long *) = res;
517				else if (flags & QUAD)
518					*va_arg(ap, quad_t *) = res;
519				else
520					*va_arg(ap, int *) = res;
521				nassigned++;
522			}
523			nread += p - buf;
524			nconversions++;
525			break;
526
527		}
528	}
529input_failure:
530	return (nconversions != 0 ? nassigned : -1);
531match_failure:
532	return (nassigned);
533}
534
535/*
536 * Fill in the given table from the scanset at the given format
537 * (just after `[').  Return a pointer to the character past the
538 * closing `]'.  The table has a 1 wherever characters should be
539 * considered part of the scanset.
540 */
541static const u_char *
542__sccl(char *tab, const u_char *fmt)
543{
544	int c, n, v;
545
546	/* first `clear' the whole table */
547	c = *fmt++;		/* first char hat => negated scanset */
548	if (c == '^') {
549		v = 1;		/* default => accept */
550		c = *fmt++;	/* get new first char */
551	} else
552		v = 0;		/* default => reject */
553
554	/* XXX: Will not work if sizeof(tab*) > sizeof(char) */
555	for (n = 0; n < 256; n++)
556		     tab[n] = v;	/* memset(tab, v, 256) */
557
558	if (c == 0)
559		return (fmt - 1);/* format ended before closing ] */
560
561	/*
562	 * Now set the entries corresponding to the actual scanset
563	 * to the opposite of the above.
564	 *
565	 * The first character may be ']' (or '-') without being special;
566	 * the last character may be '-'.
567	 */
568	v = 1 - v;
569	for (;;) {
570		tab[c] = v;		/* take character c */
571doswitch:
572		n = *fmt++;		/* and examine the next */
573		switch (n) {
574
575		case 0:			/* format ended too soon */
576			return (fmt - 1);
577
578		case '-':
579			/*
580			 * A scanset of the form
581			 *	[01+-]
582			 * is defined as `the digit 0, the digit 1,
583			 * the character +, the character -', but
584			 * the effect of a scanset such as
585			 *	[a-zA-Z0-9]
586			 * is implementation defined.  The V7 Unix
587			 * scanf treats `a-z' as `the letters a through
588			 * z', but treats `a-a' as `the letter a, the
589			 * character -, and the letter a'.
590			 *
591			 * For compatibility, the `-' is not considerd
592			 * to define a range if the character following
593			 * it is either a close bracket (required by ANSI)
594			 * or is not numerically greater than the character
595			 * we just stored in the table (c).
596			 */
597			n = *fmt;
598			if (n == ']' || n < c) {
599				c = '-';
600				break;	/* resume the for(;;) */
601			}
602			fmt++;
603			/* fill in the range */
604			do {
605			    tab[++c] = v;
606			} while (c < n);
607			c = n;
608			/*
609			 * Alas, the V7 Unix scanf also treats formats
610			 * such as [a-c-e] as `the letters a through e'.
611			 * This too is permitted by the standard....
612			 */
613			goto doswitch;
614			break;
615
616		case ']':		/* end of scanset */
617			return (fmt);
618
619		default:		/* just another character */
620			c = n;
621			break;
622		}
623	}
624	/* NOTREACHED */
625}
626
627