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  * 3. 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  * $FreeBSD: src/sys/kern/subr_scanf.c,v 1.13 1999/11/24 01:03:01 archie Exp $
  33  * $DragonFly: src/sys/kern/subr_scanf.c,v 1.4 2006/12/13 21:58:50 dillon Exp $
  34  * From: Id: vfscanf.c,v 1.13 1998/09/25 12:20:27 obrien Exp
  35  * From: static char sccsid[] = "@(#)strtol.c   8.1 (Berkeley) 6/4/93";
  36  * From: static char sccsid[] = "@(#)strtoul.c  8.1 (Berkeley) 6/4/93";
  37  */
  38
  39 #include <sys/param.h>
  40 #include <sys/systm.h>
  41 #include <sys/ctype.h>
  42 #include <machine/limits.h>
  43
  44 /*
  45  * Note that stdarg.h and the ANSI style va_start macro is used for both
  46  * ANSI and traditional C compilers.
  47  */
  48 #include <machine/stdarg.h>
  49
  50 #define BUF             32      /* Maximum length of numeric string. */
  51
  52 /*
  53  * Flags used during conversion.
  54  */
  55 #define LONG            0x01    /* l: long or double */
  56 #define SHORT           0x04    /* h: short */
  57 #define SUPPRESS        0x08    /* suppress assignment */
  58 #define POINTER         0x10    /* weird %p pointer (`fake hex') */
  59 #define NOSKIP          0x20    /* do not skip blanks */
  60 #define QUAD            0x400
  61 #define SHORTSHORT      0x4000  /* hh: char */
  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 ksscanf(const char *ibuf, const char *fmt, ...)
  90 {
  91         __va_list ap;
  92         int ret;
  93
  94         __va_start(ap, fmt);
  95         ret = kvsscanf(ibuf, fmt, ap);
  96         __va_end(ap);
  97         return(ret);
  98 }
  99
 100 int
 101 kvsscanf(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                         if (flags & SHORT) {
 170                                 flags &= ~SHORT;
 171                                 flags |= SHORTSHORT;
 172                         } else
 173                                 flags |= SHORT;
 174                         goto again;
 175
 176                 case '0': case '1': case '2': case '3': case '4':
 177                 case '5': case '6': case '7': case '8': case '9':
 178                         width = width * 10 + c - '0';
 179                         goto again;
 180
 181                 /*
 182                  * Conversions.
 183                  *
 184                  */
 185                 case 'd':
 186                         c = CT_INT;
 187                         ccfn = (ccfntype)strtoq;
 188                         base = 10;
 189                         break;
 190
 191                 case 'i':
 192                         c = CT_INT;
 193                         ccfn = (ccfntype)strtoq;
 194                         base = 0;
 195                         break;
 196
 197                 case 'o':
 198                         c = CT_INT;
 199                         ccfn = strtouq;
 200                         base = 8;
 201                         break;
 202
 203                 case 'u':
 204                         c = CT_INT;
 205                         ccfn = strtouq;
 206                         base = 10;
 207                         break;
 208
 209                 case 'x':
 210                         flags |= PFXOK; /* enable 0x prefixing */
 211                         c = CT_INT;
 212                         ccfn = strtouq;
 213                         base = 16;
 214                         break;
 215
 216                 case 's':
 217                         c = CT_STRING;
 218                         break;
 219
 220                 case '[':
 221                         fmt = __sccl(ccltab, fmt);
 222                         flags |= NOSKIP;
 223                         c = CT_CCL;
 224                         break;
 225
 226                 case 'c':
 227                         flags |= NOSKIP;
 228                         c = CT_CHAR;
 229                         break;
 230
 231                 case 'p':       /* pointer format is like hex */
 232                         flags |= POINTER | PFXOK;
 233                         c = CT_INT;
 234                         ccfn = strtouq;
 235                         base = 16;
 236                         break;
 237
 238                 case 'n':
 239                         nconversions++;
 240                         if (flags & SUPPRESS)   /* ??? */
 241                                 continue;
 242                         if (flags & SHORTSHORT)
 243                                 *__va_arg(ap, char *) = nread;
 244                         else if (flags & SHORT)
 245                                 *__va_arg(ap, short *) = nread;
 246                         else if (flags & LONG)
 247                                 *__va_arg(ap, long *) = nread;
 248                         else if (flags & QUAD)
 249                                 *__va_arg(ap, quad_t *) = nread;
 250                         else
 251                                 *__va_arg(ap, int *) = nread;
 252                         continue;
 253                 }
 254
 255                 /*
 256                  * We have a conversion that requires input.
 257                  */
 258                 if (inr <= 0)
 259                         goto input_failure;
 260
 261                 /*
 262                  * Consume leading white space, except for formats
 263                  * that suppress this.
 264                  */
 265                 if ((flags & NOSKIP) == 0) {
 266                         while (isspace(*inp)) {
 267                                 nread++;
 268                                 if (--inr > 0)
 269                                         inp++;
 270                                 else
 271                                         goto input_failure;
 272                         }
 273                         /*
 274                          * Note that there is at least one character in
 275                          * the buffer, so conversions that do not set NOSKIP
 276                          * can no longer result in an input failure.
 277                          */
 278                 }
 279
 280                 /*
 281                  * Do the conversion.
 282                  */
 283                 switch (c) {
 284
 285                 case CT_CHAR:
 286                         /* scan arbitrary characters (sets NOSKIP) */
 287                         if (width == 0)
 288                                 width = 1;
 289                         if (flags & SUPPRESS) {
 290                                 size_t sum = 0;
 291                                 for (;;) {
 292                                         if ((n = inr) < width) {
 293                                                 sum += n;
 294                                                 width -= n;
 295                                                 inp += n;
 296                                                 if (sum == 0)
 297                                                         goto input_failure;
 298                                                 break;
 299                                         } else {
 300                                                 sum += width;
 301                                                 inr -= width;
 302                                                 inp += width;
 303                                                 break;
 304                                         }
 305                                 }
 306                                 nread += sum;
 307                         } else {
 308                                 bcopy(inp, __va_arg(ap, char *), width);
 309                                 inr -= width;
 310                                 inp += width;
 311                                 nread += width;
 312                                 nassigned++;
 313                         }
 314                         nconversions++;
 315                         break;
 316
 317                 case CT_CCL:
 318                         /* scan a (nonempty) character class (sets NOSKIP) */
 319                         if (width == 0)
 320                                 width = (size_t)~0;     /* `infinity' */
 321                         /* take only those things in the class */
 322                         if (flags & SUPPRESS) {
 323                                 n = 0;
 324                                 while (ccltab[(unsigned char)*inp]) {
 325                                         n++, inr--, inp++;
 326                                         if (--width == 0)
 327                                                 break;
 328                                         if (inr <= 0) {
 329                                                 if (n == 0)
 330                                                         goto input_failure;
 331                                                 break;
 332                                         }
 333                                 }
 334                                 if (n == 0)
 335                                         goto match_failure;
 336                         } else {
 337                                 p0 = p = __va_arg(ap, char *);
 338                                 while (ccltab[(unsigned char)*inp]) {
 339                                         inr--;
 340                                         *p++ = *inp++;
 341                                         if (--width == 0)
 342                                                 break;
 343                                         if (inr <= 0) {
 344                                                 if (p == p0)
 345                                                         goto input_failure;
 346                                                 break;
 347                                         }
 348                                 }
 349                                 n = p - p0;
 350                                 if (n == 0)
 351                                         goto match_failure;
 352                                 *p = 0;
 353                                 nassigned++;
 354                         }
 355                         nread += n;
 356                         nconversions++;
 357                         break;
 358
 359                 case CT_STRING:
 360                         /* like CCL, but zero-length string OK, & no NOSKIP */
 361                         if (width == 0)
 362                                 width = (size_t)~0;
 363                         if (flags & SUPPRESS) {
 364                                 n = 0;
 365                                 while (!isspace(*inp)) {
 366                                         n++, inr--, inp++;
 367                                         if (--width == 0)
 368                                                 break;
 369                                         if (inr <= 0)
 370                                                 break;
 371                                 }
 372                                 nread += n;
 373                         } else {
 374                                 p0 = p = __va_arg(ap, char *);
 375                                 while (!isspace(*inp)) {
 376                                         inr--;
 377                                         *p++ = *inp++;
 378                                         if (--width == 0)
 379                                                 break;
 380                                         if (inr <= 0)
 381                                                 break;
 382                                 }
 383                                 *p = 0;
 384                                 nread += p - p0;
 385                                 nassigned++;
 386                         }
 387                         nconversions++;
 388                         continue;
 389
 390                 case CT_INT:
 391                         /* scan an integer as if by strtoq/strtouq */
 392 #ifdef hardway
 393                         if (width == 0 || width > sizeof(buf) - 1)
 394                                 width = sizeof(buf) - 1;
 395 #else
 396                         /* size_t is unsigned, hence this optimisation */
 397                         if (--width > sizeof(buf) - 2)
 398                                 width = sizeof(buf) - 2;
 399                         width++;
 400 #endif
 401                         flags |= SIGNOK | NDIGITS | NZDIGITS;
 402                         for (p = buf; width; width--) {
 403                                 c = *inp;
 404                                 /*
 405                                  * Switch on the character; `goto ok'
 406                                  * if we accept it as a part of number.
 407                                  */
 408                                 switch (c) {
 409
 410                                 /*
 411                                  * The digit 0 is always legal, but is
 412                                  * special.  For %i conversions, if no
 413                                  * digits (zero or nonzero) have been
 414                                  * scanned (only signs), we will have
 415                                  * base==0.  In that case, we should set
 416                                  * it to 8 and enable 0x prefixing.
 417                                  * Also, if we have not scanned zero digits
 418                                  * before this, do not turn off prefixing
 419                                  * (someone else will turn it off if we
 420                                  * have scanned any nonzero digits).
 421                                  */
 422                                 case '0':
 423                                         if (base == 0) {
 424                                                 base = 8;
 425                                                 flags |= PFXOK;
 426                                         }
 427                                         if (flags & NZDIGITS)
 428                                             flags &= ~(SIGNOK|NZDIGITS|NDIGITS);
 429                                         else
 430                                             flags &= ~(SIGNOK|PFXOK|NDIGITS);
 431                                         goto ok;
 432
 433                                 /* 1 through 7 always legal */
 434                                 case '1': case '2': case '3':
 435                                 case '4': case '5': case '6': case '7':
 436                                         base = basefix[base];
 437                                         flags &= ~(SIGNOK | PFXOK | NDIGITS);
 438                                         goto ok;
 439
 440                                 /* digits 8 and 9 ok iff decimal or hex */
 441                                 case '8': case '9':
 442                                         base = basefix[base];
 443                                         if (base <= 8)
 444                                                 break;  /* not legal here */
 445                                         flags &= ~(SIGNOK | PFXOK | NDIGITS);
 446                                         goto ok;
 447
 448                                 /* letters ok iff hex */
 449                                 case 'A': case 'B': case 'C':
 450                                 case 'D': case 'E': case 'F':
 451                                 case 'a': case 'b': case 'c':
 452                                 case 'd': case 'e': case 'f':
 453                                         /* no need to fix base here */
 454                                         if (base <= 10)
 455                                                 break;  /* not legal here */
 456                                         flags &= ~(SIGNOK | PFXOK | NDIGITS);
 457                                         goto ok;
 458
 459                                 /* sign ok only as first character */
 460                                 case '+': case '-':
 461                                         if (flags & SIGNOK) {
 462                                                 flags &= ~SIGNOK;
 463                                                 goto ok;
 464                                         }
 465                                         break;
 466
 467                                 /* x ok iff flag still set & 2nd char */
 468                                 case 'x': case 'X':
 469                                         if (flags & PFXOK && p == buf + 1) {
 470                                                 base = 16;      /* if %i */
 471                                                 flags &= ~PFXOK;
 472                                                 goto ok;
 473                                         }
 474                                         break;
 475                                 }
 476
 477                                 /*
 478                                  * If we got here, c is not a legal character
 479                                  * for a number.  Stop accumulating digits.
 480                                  */
 481                                 break;
 482                 ok:
 483                                 /*
 484                                  * c is legal: store it and look at the next.
 485                                  */
 486                                 *p++ = c;
 487                                 if (--inr > 0)
 488                                         inp++;
 489                                 else
 490                                         break;          /* end of input */
 491                         }
 492                         /*
 493                          * If we had only a sign, it is no good; push
 494                          * back the sign.  If the number ends in `x',
 495                          * it was [sign] '0' 'x', so push back the x
 496                          * and treat it as [sign] '0'.
 497                          */
 498                         if (flags & NDIGITS) {
 499                                 if (p > buf) {
 500                                         inp--;
 501                                         inr++;
 502                                 }
 503                                 goto match_failure;
 504                         }
 505                         c = ((u_char *)p)[-1];
 506                         if (c == 'x' || c == 'X') {
 507                                 --p;
 508                                 inp--;
 509                                 inr++;
 510                         }
 511                         if ((flags & SUPPRESS) == 0) {
 512                                 u_quad_t res;
 513
 514                                 *p = 0;
 515                                 res = (*ccfn)(buf, NULL, base);
 516                                 if (flags & POINTER)
 517                                         *__va_arg(ap, void **) =
 518                                                 (void *)(uintptr_t)res;
 519                                 else if (flags & SHORTSHORT)
 520                                         *__va_arg(ap, char *) = res;
 521                                 else if (flags & SHORT)
 522                                         *__va_arg(ap, short *) = res;
 523                                 else if (flags & LONG)
 524                                         *__va_arg(ap, long *) = res;
 525                                 else if (flags & QUAD)
 526                                         *__va_arg(ap, quad_t *) = res;
 527                                 else
 528                                         *__va_arg(ap, int *) = res;
 529                                 nassigned++;
 530                         }
 531                         nread += p - buf;
 532                         nconversions++;
 533                         break;
 534
 535                 }
 536         }
 537 input_failure:
 538         return (nconversions != 0 ? nassigned : -1);
 539 match_failure:
 540         return (nassigned);
 541 }
 542
 543 /*
 544  * Fill in the given table from the scanset at the given format
 545  * (just after `[').  Return a pointer to the character past the
 546  * closing `]'.  The table has a 1 wherever characters should be
 547  * considered part of the scanset.
 548  */
 549 static const u_char *
 550 __sccl(char *tab, const u_char *fmt)
 551 {
 552         int c, n, v;
 553
 554         /* first `clear' the whole table */
 555         c = *fmt++;             /* first char hat => negated scanset */
 556         if (c == '^') {
 557                 v = 1;          /* default => accept */
 558                 c = *fmt++;     /* get new first char */
 559         } else
 560                 v = 0;          /* default => reject */
 561
 562         /* XXX: Will not work if sizeof(tab*) > sizeof(char) */
 563         for (n = 0; n < 256; n++)
 564                      tab[n] = v;        /* memset(tab, v, 256) */
 565
 566         if (c == 0)
 567                 return (fmt - 1);/* format ended before closing ] */
 568
 569         /*
 570          * Now set the entries corresponding to the actual scanset
 571          * to the opposite of the above.
 572          *
 573          * The first character may be ']' (or '-') without being special;
 574          * the last character may be '-'.
 575          */
 576         v = 1 - v;
 577         for (;;) {
 578                 tab[c] = v;             /* take character c */
 579 doswitch:
 580                 n = *fmt++;             /* and examine the next */
 581                 switch (n) {
 582
 583                 case 0:                 /* format ended too soon */
 584                         return (fmt - 1);
 585
 586                 case '-':
 587                         /*
 588                          * A scanset of the form
 589                          *      [01+-]
 590                          * is defined as `the digit 0, the digit 1,
 591                          * the character +, the character -', but
 592                          * the effect of a scanset such as
 593                          *      [a-zA-Z0-9]
 594                          * is implementation defined.  The V7 Unix
 595                          * scanf treats `a-z' as `the letters a through
 596                          * z', but treats `a-a' as `the letter a, the
 597                          * character -, and the letter a'.
 598                          *
 599                          * For compatibility, the `-' is not considerd
 600                          * to define a range if the character following
 601                          * it is either a close bracket (required by ANSI)
 602                          * or is not numerically greater than the character
 603                          * we just stored in the table (c).
 604                          */
 605                         n = *fmt;
 606                         if (n == ']' || n < c) {
 607                                 c = '-';
 608                                 break;  /* resume the for(;;) */
 609                         }
 610                         fmt++;
 611                         /* fill in the range */
 612                         do {
 613                             tab[++c] = v;
 614                         } while (c < n);
 615                         c = n;
 616                         /*
 617                          * Alas, the V7 Unix scanf also treats formats
 618                          * such as [a-c-e] as `the letters a through e'.
 619                          * This too is permitted by the standard....
 620                          */
 621                         goto doswitch;
 622                         break;
 623
 624                 case ']':               /* end of scanset */
 625                         return (fmt);
 626
 627                 default:                /* just another character */
 628                         c = n;
 629                         break;
 630                 }
 631         }
 632         /* NOTREACHED */
 633 }
 634