FreeBSD/Linux Kernel Cross Reference
sys/kern/subr_scanf.c
1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1990, 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * This code is derived from software contributed to Berkeley by
8 * Chris Torek.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. Neither the name of the University nor the names of its contributors
19 * may be used to endorse or promote products derived from this software
20 * without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 *
34 * From: Id: vfscanf.c,v 1.13 1998/09/25 12:20:27 obrien Exp
35 * From: static char sccsid[] = "@(#)strtol.c 8.1 (Berkeley) 6/4/93";
36 * From: static char sccsid[] = "@(#)strtoul.c 8.1 (Berkeley) 6/4/93";
37 */
38
39 #include <sys/cdefs.h>
40 __FBSDID("$FreeBSD$");
41
42 #include <sys/param.h>
43 #include <sys/systm.h>
44 #include <sys/ctype.h>
45 #include <sys/limits.h>
46 #include <sys/stddef.h>
47
48 /*
49 * Note that stdarg.h and the ANSI style va_start macro is used for both
50 * ANSI and traditional C compilers.
51 */
52 #include <machine/stdarg.h>
53
54 #define BUF 32 /* Maximum length of numeric string. */
55
56 /*
57 * Flags used during conversion.
58 */
59 #define LONG 0x01 /* l: long or double */
60 #define SHORT 0x04 /* h: short */
61 #define SUPPRESS 0x08 /* suppress assignment */
62 #define POINTER 0x10 /* weird %p pointer (`fake hex') */
63 #define NOSKIP 0x20 /* do not skip blanks */
64 #define QUAD 0x400
65 #define INTMAXT 0x800 /* j: intmax_t */
66 #define PTRDIFFT 0x1000 /* t: ptrdiff_t */
67 #define SIZET 0x2000 /* z: size_t */
68 #define SHORTSHORT 0x4000 /** hh: char */
69
70 /*
71 * The following are used in numeric conversions only:
72 * SIGNOK, NDIGITS, DPTOK, and EXPOK are for floating point;
73 * SIGNOK, NDIGITS, PFXOK, and NZDIGITS are for integral.
74 */
75 #define SIGNOK 0x40 /* +/- is (still) legal */
76 #define NDIGITS 0x80 /* no digits detected */
77
78 #define DPTOK 0x100 /* (float) decimal point is still legal */
79 #define EXPOK 0x200 /* (float) exponent (e+3, etc) still legal */
80
81 #define PFXOK 0x100 /* 0x prefix is (still) legal */
82 #define NZDIGITS 0x200 /* no zero digits detected */
83
84 /*
85 * Conversion types.
86 */
87 #define CT_CHAR 0 /* %c conversion */
88 #define CT_CCL 1 /* %[...] conversion */
89 #define CT_STRING 2 /* %s conversion */
90 #define CT_INT 3 /* integer, i.e., strtoq or strtouq */
91 typedef u_quad_t (*ccfntype)(const char *, char **, int);
92
93 static const u_char *__sccl(char *, const u_char *);
94
95 int
96 sscanf(const char *ibuf, const char *fmt, ...)
97 {
98 va_list ap;
99 int ret;
100
101 va_start(ap, fmt);
102 ret = vsscanf(ibuf, fmt, ap);
103 va_end(ap);
104 return(ret);
105 }
106
107 int
108 vsscanf(const char *inp, char const *fmt0, va_list ap)
109 {
110 int inr;
111 const u_char *fmt = (const u_char *)fmt0;
112 int c; /* character from format, or conversion */
113 size_t width; /* field width, or 0 */
114 char *p; /* points into all kinds of strings */
115 int n; /* handy integer */
116 int flags; /* flags as defined above */
117 char *p0; /* saves original value of p when necessary */
118 int nassigned; /* number of fields assigned */
119 int nconversions; /* number of conversions */
120 int nread; /* number of characters consumed from fp */
121 int base; /* base argument to strtoq/strtouq */
122 ccfntype ccfn; /* conversion function (strtoq/strtouq) */
123 char ccltab[256]; /* character class table for %[...] */
124 char buf[BUF]; /* buffer for numeric conversions */
125
126 /* `basefix' is used to avoid `if' tests in the integer scanner */
127 static short basefix[17] =
128 { 10, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 };
129
130 inr = strlen(inp);
131
132 nassigned = 0;
133 nconversions = 0;
134 nread = 0;
135 base = 0; /* XXX just to keep gcc happy */
136 ccfn = NULL; /* XXX just to keep gcc happy */
137 for (;;) {
138 c = *fmt++;
139 if (c == 0)
140 return (nassigned);
141 if (isspace(c)) {
142 while (inr > 0 && isspace(*inp))
143 nread++, inr--, inp++;
144 continue;
145 }
146 if (c != '%')
147 goto literal;
148 width = 0;
149 flags = 0;
150 /*
151 * switch on the format. continue if done;
152 * break once format type is derived.
153 */
154 again: c = *fmt++;
155 switch (c) {
156 case '%':
157 literal:
158 if (inr <= 0)
159 goto input_failure;
160 if (*inp != c)
161 goto match_failure;
162 inr--, inp++;
163 nread++;
164 continue;
165
166 case '*':
167 flags |= SUPPRESS;
168 goto again;
169 case 'j':
170 flags |= INTMAXT;
171 goto again;
172 case 'l':
173 if (flags & LONG){
174 flags &= ~LONG;
175 flags |= QUAD;
176 } else {
177 flags |= LONG;
178 }
179 goto again;
180 case 'q':
181 flags |= QUAD;
182 goto again;
183 case 't':
184 flags |= PTRDIFFT;
185 goto again;
186 case 'z':
187 flags |= SIZET;
188 goto again;
189 case 'h':
190 if (flags & SHORT){
191 flags &= ~SHORT;
192 flags |= SHORTSHORT;
193 } else {
194 flags |= SHORT;
195 }
196 goto again;
197
198 case '': case '1': case '2': case '3': case '4':
199 case '5': case '6': case '7': case '8': case '9':
200 width = width * 10 + c - '';
201 goto again;
202
203 /*
204 * Conversions.
205 *
206 */
207 case 'd':
208 c = CT_INT;
209 ccfn = (ccfntype)strtoq;
210 base = 10;
211 break;
212
213 case 'i':
214 c = CT_INT;
215 ccfn = (ccfntype)strtoq;
216 base = 0;
217 break;
218
219 case 'o':
220 c = CT_INT;
221 ccfn = strtouq;
222 base = 8;
223 break;
224
225 case 'u':
226 c = CT_INT;
227 ccfn = strtouq;
228 base = 10;
229 break;
230
231 case 'x':
232 flags |= PFXOK; /* enable 0x prefixing */
233 c = CT_INT;
234 ccfn = strtouq;
235 base = 16;
236 break;
237
238 case 's':
239 c = CT_STRING;
240 break;
241
242 case '[':
243 fmt = __sccl(ccltab, fmt);
244 flags |= NOSKIP;
245 c = CT_CCL;
246 break;
247
248 case 'c':
249 flags |= NOSKIP;
250 c = CT_CHAR;
251 break;
252
253 case 'p': /* pointer format is like hex */
254 flags |= POINTER | PFXOK;
255 c = CT_INT;
256 ccfn = strtouq;
257 base = 16;
258 break;
259
260 case 'n':
261 nconversions++;
262 if (flags & SUPPRESS) /* ??? */
263 continue;
264 if (flags & SHORTSHORT)
265 *va_arg(ap, char *) = nread;
266 else if (flags & SHORT)
267 *va_arg(ap, short *) = nread;
268 else if (flags & LONG)
269 *va_arg(ap, long *) = nread;
270 else if (flags & QUAD)
271 *va_arg(ap, quad_t *) = nread;
272 else if (flags & INTMAXT)
273 *va_arg(ap, intmax_t *) = nread;
274 else if (flags & SIZET)
275 *va_arg(ap, size_t *) = nread;
276 else if (flags & PTRDIFFT)
277 *va_arg(ap, ptrdiff_t *) = nread;
278 else
279 *va_arg(ap, int *) = nread;
280 continue;
281 }
282
283 /*
284 * We have a conversion that requires input.
285 */
286 if (inr <= 0)
287 goto input_failure;
288
289 /*
290 * Consume leading white space, except for formats
291 * that suppress this.
292 */
293 if ((flags & NOSKIP) == 0) {
294 while (isspace(*inp)) {
295 nread++;
296 if (--inr > 0)
297 inp++;
298 else
299 goto input_failure;
300 }
301 /*
302 * Note that there is at least one character in
303 * the buffer, so conversions that do not set NOSKIP
304 * can no longer result in an input failure.
305 */
306 }
307
308 /*
309 * Do the conversion.
310 */
311 switch (c) {
312
313 case CT_CHAR:
314 /* scan arbitrary characters (sets NOSKIP) */
315 if (width == 0)
316 width = 1;
317 if (flags & SUPPRESS) {
318 size_t sum = 0;
319 for (;;) {
320 if ((n = inr) < width) {
321 sum += n;
322 width -= n;
323 inp += n;
324 if (sum == 0)
325 goto input_failure;
326 break;
327 } else {
328 sum += width;
329 inr -= width;
330 inp += width;
331 break;
332 }
333 }
334 nread += sum;
335 } else {
336 bcopy(inp, va_arg(ap, char *), width);
337 inr -= width;
338 inp += width;
339 nread += width;
340 nassigned++;
341 }
342 nconversions++;
343 break;
344
345 case CT_CCL:
346 /* scan a (nonempty) character class (sets NOSKIP) */
347 if (width == 0)
348 width = (size_t)~0; /* `infinity' */
349 /* take only those things in the class */
350 if (flags & SUPPRESS) {
351 n = 0;
352 while (ccltab[(unsigned char)*inp]) {
353 n++, inr--, inp++;
354 if (--width == 0)
355 break;
356 if (inr <= 0) {
357 if (n == 0)
358 goto input_failure;
359 break;
360 }
361 }
362 if (n == 0)
363 goto match_failure;
364 } else {
365 p0 = p = va_arg(ap, char *);
366 while (ccltab[(unsigned char)*inp]) {
367 inr--;
368 *p++ = *inp++;
369 if (--width == 0)
370 break;
371 if (inr <= 0) {
372 if (p == p0)
373 goto input_failure;
374 break;
375 }
376 }
377 n = p - p0;
378 if (n == 0)
379 goto match_failure;
380 *p = 0;
381 nassigned++;
382 }
383 nread += n;
384 nconversions++;
385 break;
386
387 case CT_STRING:
388 /* like CCL, but zero-length string OK, & no NOSKIP */
389 if (width == 0)
390 width = (size_t)~0;
391 if (flags & SUPPRESS) {
392 n = 0;
393 while (!isspace(*inp)) {
394 n++, inr--, inp++;
395 if (--width == 0)
396 break;
397 if (inr <= 0)
398 break;
399 }
400 nread += n;
401 } else {
402 p0 = p = va_arg(ap, char *);
403 while (!isspace(*inp)) {
404 inr--;
405 *p++ = *inp++;
406 if (--width == 0)
407 break;
408 if (inr <= 0)
409 break;
410 }
411 *p = 0;
412 nread += p - p0;
413 nassigned++;
414 }
415 nconversions++;
416 continue;
417
418 case CT_INT:
419 /* scan an integer as if by strtoq/strtouq */
420 #ifdef hardway
421 if (width == 0 || width > sizeof(buf) - 1)
422 width = sizeof(buf) - 1;
423 #else
424 /* size_t is unsigned, hence this optimisation */
425 if (--width > sizeof(buf) - 2)
426 width = sizeof(buf) - 2;
427 width++;
428 #endif
429 flags |= SIGNOK | NDIGITS | NZDIGITS;
430 for (p = buf; width; width--) {
431 c = *inp;
432 /*
433 * Switch on the character; `goto ok'
434 * if we accept it as a part of number.
435 */
436 switch (c) {
437
438 /*
439 * The digit 0 is always legal, but is
440 * special. For %i conversions, if no
441 * digits (zero or nonzero) have been
442 * scanned (only signs), we will have
443 * base==0. In that case, we should set
444 * it to 8 and enable 0x prefixing.
445 * Also, if we have not scanned zero digits
446 * before this, do not turn off prefixing
447 * (someone else will turn it off if we
448 * have scanned any nonzero digits).
449 */
450 case '':
451 if (base == 0) {
452 base = 8;
453 flags |= PFXOK;
454 }
455 if (flags & NZDIGITS)
456 flags &= ~(SIGNOK|NZDIGITS|NDIGITS);
457 else
458 flags &= ~(SIGNOK|PFXOK|NDIGITS);
459 goto ok;
460
461 /* 1 through 7 always legal */
462 case '1': case '2': case '3':
463 case '4': case '5': case '6': case '7':
464 base = basefix[base];
465 flags &= ~(SIGNOK | PFXOK | NDIGITS);
466 goto ok;
467
468 /* digits 8 and 9 ok iff decimal or hex */
469 case '8': case '9':
470 base = basefix[base];
471 if (base <= 8)
472 break; /* not legal here */
473 flags &= ~(SIGNOK | PFXOK | NDIGITS);
474 goto ok;
475
476 /* letters ok iff hex */
477 case 'A': case 'B': case 'C':
478 case 'D': case 'E': case 'F':
479 case 'a': case 'b': case 'c':
480 case 'd': case 'e': case 'f':
481 /* no need to fix base here */
482 if (base <= 10)
483 break; /* not legal here */
484 flags &= ~(SIGNOK | PFXOK | NDIGITS);
485 goto ok;
486
487 /* sign ok only as first character */
488 case '+': case '-':
489 if (flags & SIGNOK) {
490 flags &= ~SIGNOK;
491 goto ok;
492 }
493 break;
494
495 /* x ok iff flag still set & 2nd char */
496 case 'x': case 'X':
497 if (flags & PFXOK && p == buf + 1) {
498 base = 16; /* if %i */
499 flags &= ~PFXOK;
500 goto ok;
501 }
502 break;
503 }
504
505 /*
506 * If we got here, c is not a legal character
507 * for a number. Stop accumulating digits.
508 */
509 break;
510 ok:
511 /*
512 * c is legal: store it and look at the next.
513 */
514 *p++ = c;
515 if (--inr > 0)
516 inp++;
517 else
518 break; /* end of input */
519 }
520 /*
521 * If we had only a sign, it is no good; push
522 * back the sign. If the number ends in `x',
523 * it was [sign] '' 'x', so push back the x
524 * and treat it as [sign] ''.
525 */
526 if (flags & NDIGITS) {
527 if (p > buf) {
528 inp--;
529 inr++;
530 }
531 goto match_failure;
532 }
533 c = ((u_char *)p)[-1];
534 if (c == 'x' || c == 'X') {
535 --p;
536 inp--;
537 inr++;
538 }
539 if ((flags & SUPPRESS) == 0) {
540 u_quad_t res;
541
542 *p = 0;
543 res = (*ccfn)(buf, (char **)NULL, base);
544 if (flags & POINTER)
545 *va_arg(ap, void **) =
546 (void *)(uintptr_t)res;
547 else if (flags & SHORTSHORT)
548 *va_arg(ap, char *) = res;
549 else if (flags & SHORT)
550 *va_arg(ap, short *) = res;
551 else if (flags & LONG)
552 *va_arg(ap, long *) = res;
553 else if (flags & QUAD)
554 *va_arg(ap, quad_t *) = res;
555 else if (flags & INTMAXT)
556 *va_arg(ap, intmax_t *) = res;
557 else if (flags & PTRDIFFT)
558 *va_arg(ap, ptrdiff_t *) = res;
559 else if (flags & SIZET)
560 *va_arg(ap, size_t *) = res;
561 else
562 *va_arg(ap, int *) = res;
563 nassigned++;
564 }
565 nread += p - buf;
566 nconversions++;
567 break;
568
569 }
570 }
571 input_failure:
572 return (nconversions != 0 ? nassigned : -1);
573 match_failure:
574 return (nassigned);
575 }
576
577 /*
578 * Fill in the given table from the scanset at the given format
579 * (just after `['). Return a pointer to the character past the
580 * closing `]'. The table has a 1 wherever characters should be
581 * considered part of the scanset.
582 */
583 static const u_char *
584 __sccl(char *tab, const u_char *fmt)
585 {
586 int c, n, v;
587
588 /* first `clear' the whole table */
589 c = *fmt++; /* first char hat => negated scanset */
590 if (c == '^') {
591 v = 1; /* default => accept */
592 c = *fmt++; /* get new first char */
593 } else
594 v = 0; /* default => reject */
595
596 /* XXX: Will not work if sizeof(tab*) > sizeof(char) */
597 for (n = 0; n < 256; n++)
598 tab[n] = v; /* memset(tab, v, 256) */
599
600 if (c == 0)
601 return (fmt - 1);/* format ended before closing ] */
602
603 /*
604 * Now set the entries corresponding to the actual scanset
605 * to the opposite of the above.
606 *
607 * The first character may be ']' (or '-') without being special;
608 * the last character may be '-'.
609 */
610 v = 1 - v;
611 for (;;) {
612 tab[c] = v; /* take character c */
613 doswitch:
614 n = *fmt++; /* and examine the next */
615 switch (n) {
616
617 case 0: /* format ended too soon */
618 return (fmt - 1);
619
620 case '-':
621 /*
622 * A scanset of the form
623 * [01+-]
624 * is defined as `the digit 0, the digit 1,
625 * the character +, the character -', but
626 * the effect of a scanset such as
627 * [a-zA-Z0-9]
628 * is implementation defined. The V7 Unix
629 * scanf treats `a-z' as `the letters a through
630 * z', but treats `a-a' as `the letter a, the
631 * character -, and the letter a'.
632 *
633 * For compatibility, the `-' is not considered
634 * to define a range if the character following
635 * it is either a close bracket (required by ANSI)
636 * or is not numerically greater than the character
637 * we just stored in the table (c).
638 */
639 n = *fmt;
640 if (n == ']' || n < c) {
641 c = '-';
642 break; /* resume the for(;;) */
643 }
644 fmt++;
645 /* fill in the range */
646 do {
647 tab[++c] = v;
648 } while (c < n);
649 c = n;
650 /*
651 * Alas, the V7 Unix scanf also treats formats
652 * such as [a-c-e] as `the letters a through e'.
653 * This too is permitted by the standard....
654 */
655 goto doswitch;
656 break;
657
658 case ']': /* end of scanset */
659 return (fmt);
660
661 default: /* just another character */
662 c = n;
663 break;
664 }
665 }
666 /* NOTREACHED */
667 }
668
Cache object: 1c69608fbc1752b28b7f368396000111
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