Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/kern/subr_scanf.c
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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: releng/10.3/sys/kern/subr_scanf.c 230587 2012-01-26 16:35:09Z ken $"); 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 #define SHORTSHORT 0x4000 /** hh: char */ 63 64 /* 65 * The following are used in numeric conversions only: 66 * SIGNOK, NDIGITS, DPTOK, and EXPOK are for floating point; 67 * SIGNOK, NDIGITS, PFXOK, and NZDIGITS are for integral. 68 */ 69 #define SIGNOK 0x40 /* +/- is (still) legal */ 70 #define NDIGITS 0x80 /* no digits detected */ 71 72 #define DPTOK 0x100 /* (float) decimal point is still legal */ 73 #define EXPOK 0x200 /* (float) exponent (e+3, etc) still legal */ 74 75 #define PFXOK 0x100 /* 0x prefix is (still) legal */ 76 #define NZDIGITS 0x200 /* no zero digits detected */ 77 78 /* 79 * Conversion types. 80 */ 81 #define CT_CHAR 0 /* %c conversion */ 82 #define CT_CCL 1 /* %[...] conversion */ 83 #define CT_STRING 2 /* %s conversion */ 84 #define CT_INT 3 /* integer, i.e., strtoq or strtouq */ 85 typedef u_quad_t (*ccfntype)(const char *, char **, int); 86 87 static const u_char *__sccl(char *, const u_char *); 88 89 int 90 sscanf(const char *ibuf, const char *fmt, ...) 91 { 92 va_list ap; 93 int ret; 94 95 va_start(ap, fmt); 96 ret = vsscanf(ibuf, fmt, ap); 97 va_end(ap); 98 return(ret); 99 } 100 101 int 102 vsscanf(const char *inp, char const *fmt0, va_list ap) 103 { 104 int inr; 105 const u_char *fmt = (const u_char *)fmt0; 106 int c; /* character from format, or conversion */ 107 size_t width; /* field width, or 0 */ 108 char *p; /* points into all kinds of strings */ 109 int n; /* handy integer */ 110 int flags; /* flags as defined above */ 111 char *p0; /* saves original value of p when necessary */ 112 int nassigned; /* number of fields assigned */ 113 int nconversions; /* number of conversions */ 114 int nread; /* number of characters consumed from fp */ 115 int base; /* base argument to strtoq/strtouq */ 116 ccfntype ccfn; /* conversion function (strtoq/strtouq) */ 117 char ccltab[256]; /* character class table for %[...] */ 118 char buf[BUF]; /* buffer for numeric conversions */ 119 120 /* `basefix' is used to avoid `if' tests in the integer scanner */ 121 static short basefix[17] = 122 { 10, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 }; 123 124 inr = strlen(inp); 125 126 nassigned = 0; 127 nconversions = 0; 128 nread = 0; 129 base = 0; /* XXX just to keep gcc happy */ 130 ccfn = NULL; /* XXX just to keep gcc happy */ 131 for (;;) { 132 c = *fmt++; 133 if (c == 0) 134 return (nassigned); 135 if (isspace(c)) { 136 while (inr > 0 && isspace(*inp)) 137 nread++, inr--, inp++; 138 continue; 139 } 140 if (c != '%') 141 goto literal; 142 width = 0; 143 flags = 0; 144 /* 145 * switch on the format. continue if done; 146 * break once format type is derived. 147 */ 148 again: c = *fmt++; 149 switch (c) { 150 case '%': 151 literal: 152 if (inr <= 0) 153 goto input_failure; 154 if (*inp != c) 155 goto match_failure; 156 inr--, inp++; 157 nread++; 158 continue; 159 160 case '*': 161 flags |= SUPPRESS; 162 goto again; 163 case 'l': 164 if (flags & LONG){ 165 flags &= ~LONG; 166 flags |= QUAD; 167 } else { 168 flags |= LONG; 169 } 170 goto again; 171 case 'q': 172 flags |= QUAD; 173 goto again; 174 case 'h': 175 if (flags & SHORT){ 176 flags &= ~SHORT; 177 flags |= SHORTSHORT; 178 } else { 179 flags |= SHORT; 180 } 181 goto again; 182 183 case '': case '1': case '2': case '3': case '4': 184 case '5': case '6': case '7': case '8': case '9': 185 width = width * 10 + c - ''; 186 goto again; 187 188 /* 189 * Conversions. 190 * 191 */ 192 case 'd': 193 c = CT_INT; 194 ccfn = (ccfntype)strtoq; 195 base = 10; 196 break; 197 198 case 'i': 199 c = CT_INT; 200 ccfn = (ccfntype)strtoq; 201 base = 0; 202 break; 203 204 case 'o': 205 c = CT_INT; 206 ccfn = strtouq; 207 base = 8; 208 break; 209 210 case 'u': 211 c = CT_INT; 212 ccfn = strtouq; 213 base = 10; 214 break; 215 216 case 'x': 217 flags |= PFXOK; /* enable 0x prefixing */ 218 c = CT_INT; 219 ccfn = strtouq; 220 base = 16; 221 break; 222 223 case 's': 224 c = CT_STRING; 225 break; 226 227 case '[': 228 fmt = __sccl(ccltab, fmt); 229 flags |= NOSKIP; 230 c = CT_CCL; 231 break; 232 233 case 'c': 234 flags |= NOSKIP; 235 c = CT_CHAR; 236 break; 237 238 case 'p': /* pointer format is like hex */ 239 flags |= POINTER | PFXOK; 240 c = CT_INT; 241 ccfn = strtouq; 242 base = 16; 243 break; 244 245 case 'n': 246 nconversions++; 247 if (flags & SUPPRESS) /* ??? */ 248 continue; 249 if (flags & SHORTSHORT) 250 *va_arg(ap, char *) = nread; 251 else if (flags & SHORT) 252 *va_arg(ap, short *) = nread; 253 else if (flags & LONG) 254 *va_arg(ap, long *) = nread; 255 else if (flags & QUAD) 256 *va_arg(ap, quad_t *) = nread; 257 else 258 *va_arg(ap, int *) = nread; 259 continue; 260 } 261 262 /* 263 * We have a conversion that requires input. 264 */ 265 if (inr <= 0) 266 goto input_failure; 267 268 /* 269 * Consume leading white space, except for formats 270 * that suppress this. 271 */ 272 if ((flags & NOSKIP) == 0) { 273 while (isspace(*inp)) { 274 nread++; 275 if (--inr > 0) 276 inp++; 277 else 278 goto input_failure; 279 } 280 /* 281 * Note that there is at least one character in 282 * the buffer, so conversions that do not set NOSKIP 283 * can no longer result in an input failure. 284 */ 285 } 286 287 /* 288 * Do the conversion. 289 */ 290 switch (c) { 291 292 case CT_CHAR: 293 /* scan arbitrary characters (sets NOSKIP) */ 294 if (width == 0) 295 width = 1; 296 if (flags & SUPPRESS) { 297 size_t sum = 0; 298 for (;;) { 299 if ((n = inr) < width) { 300 sum += n; 301 width -= n; 302 inp += n; 303 if (sum == 0) 304 goto input_failure; 305 break; 306 } else { 307 sum += width; 308 inr -= width; 309 inp += width; 310 break; 311 } 312 } 313 nread += sum; 314 } else { 315 bcopy(inp, va_arg(ap, char *), width); 316 inr -= width; 317 inp += width; 318 nread += width; 319 nassigned++; 320 } 321 nconversions++; 322 break; 323 324 case CT_CCL: 325 /* scan a (nonempty) character class (sets NOSKIP) */ 326 if (width == 0) 327 width = (size_t)~0; /* `infinity' */ 328 /* take only those things in the class */ 329 if (flags & SUPPRESS) { 330 n = 0; 331 while (ccltab[(unsigned char)*inp]) { 332 n++, inr--, inp++; 333 if (--width == 0) 334 break; 335 if (inr <= 0) { 336 if (n == 0) 337 goto input_failure; 338 break; 339 } 340 } 341 if (n == 0) 342 goto match_failure; 343 } else { 344 p0 = p = va_arg(ap, char *); 345 while (ccltab[(unsigned char)*inp]) { 346 inr--; 347 *p++ = *inp++; 348 if (--width == 0) 349 break; 350 if (inr <= 0) { 351 if (p == p0) 352 goto input_failure; 353 break; 354 } 355 } 356 n = p - p0; 357 if (n == 0) 358 goto match_failure; 359 *p = 0; 360 nassigned++; 361 } 362 nread += n; 363 nconversions++; 364 break; 365 366 case CT_STRING: 367 /* like CCL, but zero-length string OK, & no NOSKIP */ 368 if (width == 0) 369 width = (size_t)~0; 370 if (flags & SUPPRESS) { 371 n = 0; 372 while (!isspace(*inp)) { 373 n++, inr--, inp++; 374 if (--width == 0) 375 break; 376 if (inr <= 0) 377 break; 378 } 379 nread += n; 380 } else { 381 p0 = p = va_arg(ap, char *); 382 while (!isspace(*inp)) { 383 inr--; 384 *p++ = *inp++; 385 if (--width == 0) 386 break; 387 if (inr <= 0) 388 break; 389 } 390 *p = 0; 391 nread += p - p0; 392 nassigned++; 393 } 394 nconversions++; 395 continue; 396 397 case CT_INT: 398 /* scan an integer as if by strtoq/strtouq */ 399 #ifdef hardway 400 if (width == 0 || width > sizeof(buf) - 1) 401 width = sizeof(buf) - 1; 402 #else 403 /* size_t is unsigned, hence this optimisation */ 404 if (--width > sizeof(buf) - 2) 405 width = sizeof(buf) - 2; 406 width++; 407 #endif 408 flags |= SIGNOK | NDIGITS | NZDIGITS; 409 for (p = buf; width; width--) { 410 c = *inp; 411 /* 412 * Switch on the character; `goto ok' 413 * if we accept it as a part of number. 414 */ 415 switch (c) { 416 417 /* 418 * The digit 0 is always legal, but is 419 * special. For %i conversions, if no 420 * digits (zero or nonzero) have been 421 * scanned (only signs), we will have 422 * base==0. In that case, we should set 423 * it to 8 and enable 0x prefixing. 424 * Also, if we have not scanned zero digits 425 * before this, do not turn off prefixing 426 * (someone else will turn it off if we 427 * have scanned any nonzero digits). 428 */ 429 case '': 430 if (base == 0) { 431 base = 8; 432 flags |= PFXOK; 433 } 434 if (flags & NZDIGITS) 435 flags &= ~(SIGNOK|NZDIGITS|NDIGITS); 436 else 437 flags &= ~(SIGNOK|PFXOK|NDIGITS); 438 goto ok; 439 440 /* 1 through 7 always legal */ 441 case '1': case '2': case '3': 442 case '4': case '5': case '6': case '7': 443 base = basefix[base]; 444 flags &= ~(SIGNOK | PFXOK | NDIGITS); 445 goto ok; 446 447 /* digits 8 and 9 ok iff decimal or hex */ 448 case '8': case '9': 449 base = basefix[base]; 450 if (base <= 8) 451 break; /* not legal here */ 452 flags &= ~(SIGNOK | PFXOK | NDIGITS); 453 goto ok; 454 455 /* letters ok iff hex */ 456 case 'A': case 'B': case 'C': 457 case 'D': case 'E': case 'F': 458 case 'a': case 'b': case 'c': 459 case 'd': case 'e': case 'f': 460 /* no need to fix base here */ 461 if (base <= 10) 462 break; /* not legal here */ 463 flags &= ~(SIGNOK | PFXOK | NDIGITS); 464 goto ok; 465 466 /* sign ok only as first character */ 467 case '+': case '-': 468 if (flags & SIGNOK) { 469 flags &= ~SIGNOK; 470 goto ok; 471 } 472 break; 473 474 /* x ok iff flag still set & 2nd char */ 475 case 'x': case 'X': 476 if (flags & PFXOK && p == buf + 1) { 477 base = 16; /* if %i */ 478 flags &= ~PFXOK; 479 goto ok; 480 } 481 break; 482 } 483 484 /* 485 * If we got here, c is not a legal character 486 * for a number. Stop accumulating digits. 487 */ 488 break; 489 ok: 490 /* 491 * c is legal: store it and look at the next. 492 */ 493 *p++ = c; 494 if (--inr > 0) 495 inp++; 496 else 497 break; /* end of input */ 498 } 499 /* 500 * If we had only a sign, it is no good; push 501 * back the sign. If the number ends in `x', 502 * it was [sign] '' 'x', so push back the x 503 * and treat it as [sign] ''. 504 */ 505 if (flags & NDIGITS) { 506 if (p > buf) { 507 inp--; 508 inr++; 509 } 510 goto match_failure; 511 } 512 c = ((u_char *)p)[-1]; 513 if (c == 'x' || c == 'X') { 514 --p; 515 inp--; 516 inr++; 517 } 518 if ((flags & SUPPRESS) == 0) { 519 u_quad_t res; 520 521 *p = 0; 522 res = (*ccfn)(buf, (char **)NULL, base); 523 if (flags & POINTER) 524 *va_arg(ap, void **) = 525 (void *)(uintptr_t)res; 526 else if (flags & SHORTSHORT) 527 *va_arg(ap, char *) = res; 528 else if (flags & SHORT) 529 *va_arg(ap, short *) = res; 530 else if (flags & LONG) 531 *va_arg(ap, long *) = res; 532 else if (flags & QUAD) 533 *va_arg(ap, quad_t *) = res; 534 else 535 *va_arg(ap, int *) = res; 536 nassigned++; 537 } 538 nread += p - buf; 539 nconversions++; 540 break; 541 542 } 543 } 544 input_failure: 545 return (nconversions != 0 ? nassigned : -1); 546 match_failure: 547 return (nassigned); 548 } 549 550 /* 551 * Fill in the given table from the scanset at the given format 552 * (just after `['). Return a pointer to the character past the 553 * closing `]'. The table has a 1 wherever characters should be 554 * considered part of the scanset. 555 */ 556 static const u_char * 557 __sccl(char *tab, const u_char *fmt) 558 { 559 int c, n, v; 560 561 /* first `clear' the whole table */ 562 c = *fmt++; /* first char hat => negated scanset */ 563 if (c == '^') { 564 v = 1; /* default => accept */ 565 c = *fmt++; /* get new first char */ 566 } else 567 v = 0; /* default => reject */ 568 569 /* XXX: Will not work if sizeof(tab*) > sizeof(char) */ 570 for (n = 0; n < 256; n++) 571 tab[n] = v; /* memset(tab, v, 256) */ 572 573 if (c == 0) 574 return (fmt - 1);/* format ended before closing ] */ 575 576 /* 577 * Now set the entries corresponding to the actual scanset 578 * to the opposite of the above. 579 * 580 * The first character may be ']' (or '-') without being special; 581 * the last character may be '-'. 582 */ 583 v = 1 - v; 584 for (;;) { 585 tab[c] = v; /* take character c */ 586 doswitch: 587 n = *fmt++; /* and examine the next */ 588 switch (n) { 589 590 case 0: /* format ended too soon */ 591 return (fmt - 1); 592 593 case '-': 594 /* 595 * A scanset of the form 596 * [01+-] 597 * is defined as `the digit 0, the digit 1, 598 * the character +, the character -', but 599 * the effect of a scanset such as 600 * [a-zA-Z0-9] 601 * is implementation defined. The V7 Unix 602 * scanf treats `a-z' as `the letters a through 603 * z', but treats `a-a' as `the letter a, the 604 * character -, and the letter a'. 605 * 606 * For compatibility, the `-' is not considerd 607 * to define a range if the character following 608 * it is either a close bracket (required by ANSI) 609 * or is not numerically greater than the character 610 * we just stored in the table (c). 611 */ 612 n = *fmt; 613 if (n == ']' || n < c) { 614 c = '-'; 615 break; /* resume the for(;;) */ 616 } 617 fmt++; 618 /* fill in the range */ 619 do { 620 tab[++c] = v; 621 } while (c < n); 622 c = n; 623 /* 624 * Alas, the V7 Unix scanf also treats formats 625 * such as [a-c-e] as `the letters a through e'. 626 * This too is permitted by the standard.... 627 */ 628 goto doswitch; 629 break; 630 631 case ']': /* end of scanset */ 632 return (fmt); 633 634 default: /* just another character */ 635 c = n; 636 break; 637 } 638 } 639 /* NOTREACHED */ 640 } 641
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