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 * 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 case CT_CHAR: 313 /* scan arbitrary characters (sets NOSKIP) */ 314 if (width == 0) 315 width = 1; 316 if (flags & SUPPRESS) { 317 size_t sum = 0; 318 for (;;) { 319 if ((n = inr) < width) { 320 sum += n; 321 width -= n; 322 inp += n; 323 if (sum == 0) 324 goto input_failure; 325 break; 326 } else { 327 sum += width; 328 inr -= width; 329 inp += width; 330 break; 331 } 332 } 333 nread += sum; 334 } else { 335 bcopy(inp, va_arg(ap, char *), width); 336 inr -= width; 337 inp += width; 338 nread += width; 339 nassigned++; 340 } 341 nconversions++; 342 break; 343 344 case CT_CCL: 345 /* scan a (nonempty) character class (sets NOSKIP) */ 346 if (width == 0) 347 width = (size_t)~0; /* `infinity' */ 348 /* take only those things in the class */ 349 if (flags & SUPPRESS) { 350 n = 0; 351 while (ccltab[(unsigned char)*inp]) { 352 n++, inr--, inp++; 353 if (--width == 0) 354 break; 355 if (inr <= 0) { 356 if (n == 0) 357 goto input_failure; 358 break; 359 } 360 } 361 if (n == 0) 362 goto match_failure; 363 } else { 364 p0 = p = va_arg(ap, char *); 365 while (ccltab[(unsigned char)*inp]) { 366 inr--; 367 *p++ = *inp++; 368 if (--width == 0) 369 break; 370 if (inr <= 0) { 371 if (p == p0) 372 goto input_failure; 373 break; 374 } 375 } 376 n = p - p0; 377 if (n == 0) 378 goto match_failure; 379 *p = 0; 380 nassigned++; 381 } 382 nread += n; 383 nconversions++; 384 break; 385 386 case CT_STRING: 387 /* like CCL, but zero-length string OK, & no NOSKIP */ 388 if (width == 0) 389 width = (size_t)~0; 390 if (flags & SUPPRESS) { 391 n = 0; 392 while (!isspace(*inp)) { 393 n++, inr--, inp++; 394 if (--width == 0) 395 break; 396 if (inr <= 0) 397 break; 398 } 399 nread += n; 400 } else { 401 p0 = p = va_arg(ap, char *); 402 while (!isspace(*inp)) { 403 inr--; 404 *p++ = *inp++; 405 if (--width == 0) 406 break; 407 if (inr <= 0) 408 break; 409 } 410 *p = 0; 411 nread += p - p0; 412 nassigned++; 413 } 414 nconversions++; 415 continue; 416 417 case CT_INT: 418 /* scan an integer as if by strtoq/strtouq */ 419 #ifdef hardway 420 if (width == 0 || width > sizeof(buf) - 1) 421 width = sizeof(buf) - 1; 422 #else 423 /* size_t is unsigned, hence this optimisation */ 424 if (--width > sizeof(buf) - 2) 425 width = sizeof(buf) - 2; 426 width++; 427 #endif 428 flags |= SIGNOK | NDIGITS | NZDIGITS; 429 for (p = buf; width; width--) { 430 c = *inp; 431 /* 432 * Switch on the character; `goto ok' 433 * if we accept it as a part of number. 434 */ 435 switch (c) { 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 input_failure: 569 return (nconversions != 0 ? nassigned : -1); 570 match_failure: 571 return (nassigned); 572 } 573 574 /* 575 * Fill in the given table from the scanset at the given format 576 * (just after `['). Return a pointer to the character past the 577 * closing `]'. The table has a 1 wherever characters should be 578 * considered part of the scanset. 579 */ 580 static const u_char * 581 __sccl(char *tab, const u_char *fmt) 582 { 583 int c, n, v; 584 585 /* first `clear' the whole table */ 586 c = *fmt++; /* first char hat => negated scanset */ 587 if (c == '^') { 588 v = 1; /* default => accept */ 589 c = *fmt++; /* get new first char */ 590 } else 591 v = 0; /* default => reject */ 592 593 /* XXX: Will not work if sizeof(tab*) > sizeof(char) */ 594 for (n = 0; n < 256; n++) 595 tab[n] = v; /* memset(tab, v, 256) */ 596 597 if (c == 0) 598 return (fmt - 1);/* format ended before closing ] */ 599 600 /* 601 * Now set the entries corresponding to the actual scanset 602 * to the opposite of the above. 603 * 604 * The first character may be ']' (or '-') without being special; 605 * the last character may be '-'. 606 */ 607 v = 1 - v; 608 for (;;) { 609 tab[c] = v; /* take character c */ 610 doswitch: 611 n = *fmt++; /* and examine the next */ 612 switch (n) { 613 case 0: /* format ended too soon */ 614 return (fmt - 1); 615 616 case '-': 617 /* 618 * A scanset of the form 619 * [01+-] 620 * is defined as `the digit 0, the digit 1, 621 * the character +, the character -', but 622 * the effect of a scanset such as 623 * [a-zA-Z0-9] 624 * is implementation defined. The V7 Unix 625 * scanf treats `a-z' as `the letters a through 626 * z', but treats `a-a' as `the letter a, the 627 * character -, and the letter a'. 628 * 629 * For compatibility, the `-' is not considered 630 * to define a range if the character following 631 * it is either a close bracket (required by ANSI) 632 * or is not numerically greater than the character 633 * we just stored in the table (c). 634 */ 635 n = *fmt; 636 if (n == ']' || n < c) { 637 c = '-'; 638 break; /* resume the for(;;) */ 639 } 640 fmt++; 641 /* fill in the range */ 642 do { 643 tab[++c] = v; 644 } while (c < n); 645 c = n; 646 /* 647 * Alas, the V7 Unix scanf also treats formats 648 * such as [a-c-e] as `the letters a through e'. 649 * This too is permitted by the standard.... 650 */ 651 goto doswitch; 652 break; 653 654 case ']': /* end of scanset */ 655 return (fmt); 656 657 default: /* just another character */ 658 c = n; 659 break; 660 } 661 } 662 /* NOTREACHED */ 663 }
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