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