libkern/stdio/scanf.c

   1 /*
   2  * Copyright (c) 2004-2016 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28 /*-
  29  * Copyright (c) 1990, 1993
  30  *      The Regents of the University of California.  All rights reserved.
  31  *
  32  * This code is derived from software contributed to Berkeley by
  33  * Chris Torek.
  34  *
  35  * Redistribution and use in source and binary forms, with or without
  36  * modification, are permitted provided that the following conditions
  37  * are met:
  38  * 1. Redistributions of source code must retain the above copyright
  39  *    notice, this list of conditions and the following disclaimer.
  40  * 2. Redistributions in binary form must reproduce the above copyright
  41  *    notice, this list of conditions and the following disclaimer in the
  42  *    documentation and/or other materials provided with the distribution.
  43  * 3. All advertising materials mentioning features or use of this software
  44  *    must display the following acknowledgement:
  45  *      This product includes software developed by the University of
  46  *      California, Berkeley and its contributors.
  47  * 4. Neither the name of the University nor the names of its contributors
  48  *    may be used to endorse or promote products derived from this software
  49  *    without specific prior written permission.
  50  *
  51  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  52  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  53  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  54  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  55  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  56  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  57  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  58  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  59  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  60  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  61  * SUCH DAMAGE.
  62  */
  63
  64 #include <sys/cdefs.h>
  65
  66 #if 0 /* XXX coming soon */
  67 #include <ctype.h>
  68 #else
  69 static inline int
  70 isspace(char c)
  71 {
  72         return c == ' ' || c == '\t' || c == '\n' || c == '\12';
  73 }
  74 #endif
  75 #include <stdarg.h>
  76 #include <string.h>
  77 #include <sys/param.h>
  78 #include <sys/systm.h>
  79
  80 #define BUF             32      /* Maximum length of numeric string. */
  81
  82 /*
  83  * Flags used during conversion.
  84  */
  85 #define LONG            0x01    /* l: long or double */
  86 #define SHORT           0x04    /* h: short */
  87 #define SUPPRESS        0x08    /* *: suppress assignment */
  88 #define POINTER         0x10    /* p: void * (as hex) */
  89 #define NOSKIP          0x20    /* [ or c: do not skip blanks */
  90 #define LONGLONG        0x400   /* ll: long long (+ deprecated q: quad) */
  91 #define SHORTSHORT      0x4000  /* hh: char */
  92 #define UNSIGNED        0x8000  /* %[oupxX] conversions */
  93
  94 /*
  95  * The following are used in numeric conversions only:
  96  * SIGNOK, NDIGITS, DPTOK, and EXPOK are for floating point;
  97  * SIGNOK, NDIGITS, PFXOK, and NZDIGITS are for integral.
  98  */
  99 #define SIGNOK          0x40    /* +/- is (still) legal */
 100 #define NDIGITS         0x80    /* no digits detected */
 101
 102 #define DPTOK           0x100   /* (float) decimal point is still legal */
 103 #define EXPOK           0x200   /* (float) exponent (e+3, etc) still legal */
 104
 105 #define PFXOK           0x100   /* 0x prefix is (still) legal */
 106 #define NZDIGITS        0x200   /* no zero digits detected */
 107
 108 /*
 109  * Conversion types.
 110  */
 111 #define CT_CHAR         0       /* %c conversion */
 112 #define CT_CCL          1       /* %[...] conversion */
 113 #define CT_STRING       2       /* %s conversion */
 114 #define CT_INT          3       /* %[dioupxX] conversion */
 115
 116 static const u_char *__sccl(char *, const u_char *);
 117
 118 int
 119 sscanf(const char *ibuf, const char *fmt, ...)
 120 {
 121         va_list ap;
 122         int ret;
 123
 124         va_start(ap, fmt);
 125         ret = vsscanf(ibuf, fmt, ap);
 126         va_end(ap);
 127         return ret;
 128 }
 129
 130 int
 131 vsscanf(const char *inp, char const *fmt0, va_list ap)
 132 {
 133         int inr;
 134         const u_char *fmt = (const u_char *)fmt0;
 135         int c;                  /* character from format, or conversion */
 136         size_t width;           /* field width, or 0 */
 137         char *p;                /* points into all kinds of strings */
 138         int n;                  /* handy integer */
 139         int flags;              /* flags as defined above */
 140         char *p0;               /* saves original value of p when necessary */
 141         int nassigned;          /* number of fields assigned */
 142         int nconversions;       /* number of conversions */
 143         int nread;              /* number of characters consumed from fp */
 144         int base;               /* base argument to conversion function */
 145         char ccltab[256];       /* character class table for %[...] */
 146         char buf[BUF];          /* buffer for numeric conversions */
 147
 148         /* `basefix' is used to avoid `if' tests in the integer scanner */
 149         static short basefix[17] =
 150         { 10, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 };
 151
 152         inr = strlen(inp);
 153
 154         nassigned = 0;
 155         nconversions = 0;
 156         nread = 0;
 157         base = 0;               /* XXX just to keep gcc happy */
 158         for (;;) {
 159                 c = *fmt++;
 160                 if (c == 0) {
 161                         return nassigned;
 162                 }
 163                 if (isspace(c)) {
 164                         while (inr > 0 && isspace(*inp)) {
 165                                 nread++;
 166                                 inr--;
 167                                 inp++;
 168                         }
 169                         continue;
 170                 }
 171                 if (c != '%') {
 172                         goto literal;
 173                 }
 174                 width = 0;
 175                 flags = 0;
 176                 /*
 177                  * switch on the format.  continue if done;
 178                  * break once format type is derived.
 179                  */
 180 again:          c = *fmt++;
 181                 switch (c) {
 182                 case '%':
 183 literal:
 184                         if (inr <= 0) {
 185                                 goto input_failure;
 186                         }
 187                         if (*inp != c) {
 188                                 goto match_failure;
 189                         }
 190                         inr--;
 191                         inp++;
 192                         nread++;
 193                         continue;
 194
 195                 case '*':
 196                         flags |= SUPPRESS;
 197                         goto again;
 198                 case 'l':
 199                         if (flags & LONG) {
 200                                 flags &= ~LONG;
 201                                 flags |= LONGLONG;
 202                         } else {
 203                                 flags |= LONG;
 204                         }
 205                         goto again;
 206                 case 'q':
 207                         flags |= LONGLONG;      /* not quite */
 208                         goto again;
 209                 case 'h':
 210                         if (flags & SHORT) {
 211                                 flags &= ~SHORT;
 212                                 flags |= SHORTSHORT;
 213                         } else {
 214                                 flags |= SHORT;
 215                         }
 216                         goto again;
 217
 218                 case '0': case '1': case '2': case '3': case '4':
 219                 case '5': case '6': case '7': case '8': case '9':
 220                         width = width * 10 + c - '0';
 221                         goto again;
 222
 223                 /*
 224                  * Conversions.
 225                  */
 226                 case 'd':
 227                         c = CT_INT;
 228                         base = 10;
 229                         break;
 230
 231                 case 'i':
 232                         c = CT_INT;
 233                         base = 0;
 234                         break;
 235
 236                 case 'o':
 237                         c = CT_INT;
 238                         flags |= UNSIGNED;
 239                         base = 8;
 240                         break;
 241
 242                 case 'u':
 243                         c = CT_INT;
 244                         flags |= UNSIGNED;
 245                         base = 10;
 246                         break;
 247
 248                 case 'X':
 249                 case 'x':
 250                         flags |= PFXOK; /* enable 0x prefixing */
 251                         c = CT_INT;
 252                         flags |= UNSIGNED;
 253                         base = 16;
 254                         break;
 255
 256                 case 's':
 257                         c = CT_STRING;
 258                         break;
 259
 260                 case '[':
 261                         fmt = __sccl(ccltab, fmt);
 262                         flags |= NOSKIP;
 263                         c = CT_CCL;
 264                         break;
 265
 266                 case 'c':
 267                         flags |= NOSKIP;
 268                         c = CT_CHAR;
 269                         break;
 270
 271                 case 'p':       /* pointer format is like hex */
 272                         flags |= POINTER | PFXOK;
 273                         c = CT_INT;
 274                         flags |= UNSIGNED;
 275                         base = 16;
 276                         break;
 277
 278                 case 'n':
 279                         nconversions++;
 280                         if (flags & SUPPRESS) { /* ??? */
 281                                 continue;
 282                         }
 283                         if (flags & SHORTSHORT) {
 284                                 *va_arg(ap, char *) = nread;
 285                         } else if (flags & SHORT) {
 286                                 *va_arg(ap, short *) = nread;
 287                         } else if (flags & LONG) {
 288                                 *va_arg(ap, long *) = nread;
 289                         } else if (flags & LONGLONG) {
 290                                 *va_arg(ap, long long *) = nread;
 291                         } else {
 292                                 *va_arg(ap, int *) = nread;
 293                         }
 294                         continue;
 295                 }
 296
 297                 /*
 298                  * We have a conversion that requires input.
 299                  */
 300                 if (inr <= 0) {
 301                         goto input_failure;
 302                 }
 303
 304                 /*
 305                  * Consume leading white space, except for formats
 306                  * that suppress this.
 307                  */
 308                 if ((flags & NOSKIP) == 0) {
 309                         while (isspace(*inp)) {
 310                                 nread++;
 311                                 if (--inr > 0) {
 312                                         inp++;
 313                                 } else {
 314                                         goto input_failure;
 315                                 }
 316                         }
 317                         /*
 318                          * Note that there is at least one character in
 319                          * the buffer, so conversions that do not set NOSKIP
 320                          * can no longer result in an input failure.
 321                          */
 322                 }
 323
 324                 /*
 325                  * Do the conversion.
 326                  */
 327                 switch (c) {
 328                 case CT_CHAR:
 329                         /* scan arbitrary characters (sets NOSKIP) */
 330                         if (width == 0) {
 331                                 width = 1;
 332                         }
 333                         if (flags & SUPPRESS) {
 334                                 size_t sum = 0;
 335                                 for (;;) {
 336                                         if ((n = inr) < (int)width) {
 337                                                 sum += n;
 338                                                 width -= n;
 339                                                 inp += n;
 340                                                 if (sum == 0) {
 341                                                         goto input_failure;
 342                                                 }
 343                                                 break;
 344                                         } else {
 345                                                 sum += width;
 346                                                 inr -= width;
 347                                                 inp += width;
 348                                                 break;
 349                                         }
 350                                 }
 351                                 nread += sum;
 352                         } else {
 353                                 bcopy(inp, va_arg(ap, char *), width);
 354                                 inr -= width;
 355                                 inp += width;
 356                                 nread += width;
 357                                 nassigned++;
 358                         }
 359                         nconversions++;
 360                         break;
 361
 362                 case CT_CCL:
 363                         /* scan a (nonempty) character class (sets NOSKIP) */
 364                         if (width == 0) {
 365                                 width = (size_t)~0;     /* `infinity' */
 366                         }
 367                         /* take only those things in the class */
 368                         if (flags & SUPPRESS) {
 369                                 n = 0;
 370                                 while (ccltab[(unsigned char)*inp]) {
 371                                         n++;
 372                                         inr--;
 373                                         inp++;
 374                                         if (--width == 0) {
 375                                                 break;
 376                                         }
 377                                         if (inr <= 0) {
 378                                                 if (n == 0) {
 379                                                         goto input_failure;
 380                                                 }
 381                                                 break;
 382                                         }
 383                                 }
 384                                 if (n == 0) {
 385                                         goto match_failure;
 386                                 }
 387                         } else {
 388                                 p0 = p = va_arg(ap, char *);
 389                                 while (ccltab[(unsigned char)*inp]) {
 390                                         inr--;
 391                                         *p++ = *inp++;
 392                                         if (--width == 0) {
 393                                                 break;
 394                                         }
 395                                         if (inr <= 0) {
 396                                                 if (p == p0) {
 397                                                         goto input_failure;
 398                                                 }
 399                                                 break;
 400                                         }
 401                                 }
 402                                 n = p - p0;
 403                                 if (n == 0) {
 404                                         goto match_failure;
 405                                 }
 406                                 *p = 0;
 407                                 nassigned++;
 408                         }
 409                         nread += n;
 410                         nconversions++;
 411                         break;
 412
 413                 case CT_STRING:
 414                         /* like CCL, but zero-length string OK, & no NOSKIP */
 415                         if (width == 0) {
 416                                 width = (size_t)~0;
 417                         }
 418                         if (flags & SUPPRESS) {
 419                                 n = 0;
 420                                 while (!isspace(*inp)) {
 421                                         n++;
 422                                         inr--;
 423                                         inp++;
 424                                         if (--width == 0) {
 425                                                 break;
 426                                         }
 427                                         if (inr <= 0) {
 428                                                 break;
 429                                         }
 430                                 }
 431                                 nread += n;
 432                         } else {
 433                                 p0 = p = va_arg(ap, char *);
 434                                 while (!isspace(*inp)) {
 435                                         inr--;
 436                                         *p++ = *inp++;
 437                                         if (--width == 0) {
 438                                                 break;
 439                                         }
 440                                         if (inr <= 0) {
 441                                                 break;
 442                                         }
 443                                 }
 444                                 *p = 0;
 445                                 nread += p - p0;
 446                                 nassigned++;
 447                         }
 448                         nconversions++;
 449                         continue;
 450
 451                 case CT_INT:
 452                         /* scan an integer as if by the conversion function */
 453 #ifdef hardway
 454                         if (width == 0 || width > sizeof(buf) - 1) {
 455                                 width = sizeof(buf) - 1;
 456                         }
 457 #else
 458                         /* size_t is unsigned, hence this optimisation */
 459                         if (--width > sizeof(buf) - 2) {
 460                                 width = sizeof(buf) - 2;
 461                         }
 462                         width++;
 463 #endif
 464                         flags |= SIGNOK | NDIGITS | NZDIGITS;
 465                         for (p = buf; width; width--) {
 466                                 c = *inp;
 467                                 /*
 468                                  * Switch on the character; `goto ok'
 469                                  * if we accept it as a part of number.
 470                                  */
 471                                 switch (c) {
 472                                 /*
 473                                  * The digit 0 is always legal, but is
 474                                  * special.  For %i conversions, if no
 475                                  * digits (zero or nonzero) have been
 476                                  * scanned (only signs), we will have
 477                                  * base==0.  In that case, we should set
 478                                  * it to 8 and enable 0x prefixing.
 479                                  * Also, if we have not scanned zero digits
 480                                  * before this, do not turn off prefixing
 481                                  * (someone else will turn it off if we
 482                                  * have scanned any nonzero digits).
 483                                  */
 484                                 case '0':
 485                                         if (base == 0) {
 486                                                 base = 8;
 487                                                 flags |= PFXOK;
 488                                         }
 489                                         if (flags & NZDIGITS) {
 490                                                 flags &= ~(SIGNOK | NZDIGITS | NDIGITS);
 491                                         } else {
 492                                                 flags &= ~(SIGNOK | PFXOK | NDIGITS);
 493                                         }
 494                                         goto ok;
 495
 496                                 /* 1 through 7 always legal */
 497                                 case '1': case '2': case '3':
 498                                 case '4': case '5': case '6': case '7':
 499                                         base = basefix[base];
 500                                         flags &= ~(SIGNOK | PFXOK | NDIGITS);
 501                                         goto ok;
 502
 503                                 /* digits 8 and 9 ok iff decimal or hex */
 504                                 case '8': case '9':
 505                                         base = basefix[base];
 506                                         if (base <= 8) {
 507                                                 break;  /* not legal here */
 508                                         }
 509                                         flags &= ~(SIGNOK | PFXOK | NDIGITS);
 510                                         goto ok;
 511
 512                                 /* letters ok iff hex */
 513                                 case 'A': case 'B': case 'C':
 514                                 case 'D': case 'E': case 'F':
 515                                 case 'a': case 'b': case 'c':
 516                                 case 'd': case 'e': case 'f':
 517                                         /* no need to fix base here */
 518                                         if (base <= 10) {
 519                                                 break;  /* not legal here */
 520                                         }
 521                                         flags &= ~(SIGNOK | PFXOK | NDIGITS);
 522                                         goto ok;
 523
 524                                 /* sign ok only as first character */
 525                                 case '+': case '-':
 526                                         if (flags & SIGNOK) {
 527                                                 flags &= ~SIGNOK;
 528                                                 goto ok;
 529                                         }
 530                                         break;
 531
 532                                 /* x ok iff flag still set & 2nd char */
 533                                 case 'x': case 'X':
 534                                         if (flags & PFXOK && p == buf + 1) {
 535                                                 base = 16;      /* if %i */
 536                                                 flags &= ~PFXOK;
 537                                                 goto ok;
 538                                         }
 539                                         break;
 540                                 }
 541
 542                                 /*
 543                                  * If we got here, c is not a legal character
 544                                  * for a number.  Stop accumulating digits.
 545                                  */
 546                                 break;
 547 ok:
 548                                 /*
 549                                  * c is legal: store it and look at the next.
 550                                  */
 551                                 *p++ = c;
 552                                 if (--inr > 0) {
 553                                         inp++;
 554                                 } else {
 555                                         break;          /* end of input */
 556                                 }
 557                         }
 558                         /*
 559                          * If we had only a sign, it is no good; push
 560                          * back the sign.  If the number ends in `x',
 561                          * it was [sign] '0' 'x', so push back the x
 562                          * and treat it as [sign] '0'.
 563                          */
 564                         if (flags & NDIGITS) {
 565                                 if (p > buf) {
 566                                         inp--;
 567                                         inr++;
 568                                 }
 569                                 goto match_failure;
 570                         }
 571                         c = ((u_char *)p)[-1];
 572                         if (c == 'x' || c == 'X') {
 573                                 --p;
 574                                 inp--;
 575                                 inr++;
 576                         }
 577                         if ((flags & SUPPRESS) == 0) {
 578                                 u_quad_t res;
 579
 580                                 *p = 0;
 581                                 if ((flags & UNSIGNED) == 0) {
 582                                         res = strtoq(buf, (char **)NULL, base);
 583                                 } else {
 584                                         res = strtouq(buf, (char **)NULL, base);
 585                                 }
 586                                 if (flags & POINTER) {
 587                                         *va_arg(ap, void **) =
 588                                             (void *)(uintptr_t)res;
 589                                 } else if (flags & SHORTSHORT) {
 590                                         *va_arg(ap, char *) = res;
 591                                 } else if (flags & SHORT) {
 592                                         *va_arg(ap, short *) = res;
 593                                 } else if (flags & LONG) {
 594                                         *va_arg(ap, long *) = res;
 595                                 } else if (flags & LONGLONG) {
 596                                         *va_arg(ap, long long *) = res;
 597                                 } else {
 598                                         *va_arg(ap, int *) = res;
 599                                 }
 600                                 nassigned++;
 601                         }
 602                         nread += p - buf;
 603                         nconversions++;
 604                         break;
 605                 }
 606         }
 607 input_failure:
 608         return nconversions != 0 ? nassigned : -1;
 609 match_failure:
 610         return nassigned;
 611 }
 612
 613 /*
 614  * Fill in the given table from the scanset at the given format
 615  * (just after `[').  Return a pointer to the character past the
 616  * closing `]'.  The table has a 1 wherever characters should be
 617  * considered part of the scanset.
 618  */
 619 static const u_char *
 620 __sccl(char *tab, const u_char *fmt)
 621 {
 622         int c, n, v;
 623
 624         /* first `clear' the whole table */
 625         c = *fmt++;             /* first char hat => negated scanset */
 626         if (c == '^') {
 627                 v = 1;          /* default => accept */
 628                 c = *fmt++;     /* get new first char */
 629         } else {
 630                 v = 0;          /* default => reject */
 631         }
 632         /* XXX: Will not work if sizeof(tab*) > sizeof(char) */
 633         (void) memset(tab, v, 256);
 634
 635         if (c == 0) {
 636                 return fmt - 1;/* format ended before closing ] */
 637         }
 638         /*
 639          * Now set the entries corresponding to the actual scanset
 640          * to the opposite of the above.
 641          *
 642          * The first character may be ']' (or '-') without being special;
 643          * the last character may be '-'.
 644          */
 645         v = 1 - v;
 646         for (;;) {
 647                 tab[c] = v;             /* take character c */
 648 doswitch:
 649                 n = *fmt++;             /* and examine the next */
 650                 switch (n) {
 651                 case 0:                 /* format ended too soon */
 652                         return fmt - 1;
 653
 654                 case '-':
 655                         /*
 656                          * A scanset of the form
 657                          *      [01+-]
 658                          * is defined as `the digit 0, the digit 1,
 659                          * the character +, the character -', but
 660                          * the effect of a scanset such as
 661                          *      [a-zA-Z0-9]
 662                          * is implementation defined.  The V7 Unix
 663                          * scanf treats `a-z' as `the letters a through
 664                          * z', but treats `a-a' as `the letter a, the
 665                          * character -, and the letter a'.
 666                          *
 667                          * For compatibility, the `-' is not considerd
 668                          * to define a range if the character following
 669                          * it is either a close bracket (required by ANSI)
 670                          * or is not numerically greater than the character
 671                          * we just stored in the table (c).
 672                          */
 673                         n = *fmt;
 674                         if (n == ']' || n < c) {
 675                                 c = '-';
 676                                 break;  /* resume the for(;;) */
 677                         }
 678                         fmt++;
 679                         /* fill in the range */
 680                         do {
 681                                 tab[++c] = v;
 682                         } while (c < n);
 683                         c = n;
 684                         /*
 685                          * Alas, the V7 Unix scanf also treats formats
 686                          * such as [a-c-e] as `the letters a through e'.
 687                          * This too is permitted by the standard....
 688                          */
 689                         goto doswitch;
 690
 691                 case ']':               /* end of scanset */
 692                         return fmt;
 693
 694                 default:                /* just another character */
 695                         c = n;
 696                         break;
 697                 }
 698         }
 699         /* NOTREACHED */
 700 }