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