sys/kern/subr_scanf.c

   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
  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 '0': case '1': case '2': case '3': case '4':
 184                 case '5': case '6': case '7': case '8': case '9':
 185                         width = width * 10 + c - '0';
 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 '0':
 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] '0' 'x', so push back the x
 503                          * and treat it as [sign] '0'.
 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