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. All advertising materials mentioning features or use of this software
  17  *    must display the following acknowledgement:
  18  *      This product includes software developed by the University of
  19  *      California, Berkeley and its contributors.
  20  * 4. Neither the name of the University nor the names of its contributors
  21  *    may be used to endorse or promote products derived from this software
  22  *    without specific prior written permission.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  34  * SUCH DAMAGE.
  35  *
  36  * $FreeBSD: src/sys/kern/subr_scanf.c,v 1.13 1999/11/24 01:03:01 archie Exp $
  37  * From: Id: vfscanf.c,v 1.13 1998/09/25 12:20:27 obrien Exp
  38  * From: static char sccsid[] = "@(#)strtol.c   8.1 (Berkeley) 6/4/93";
  39  * From: static char sccsid[] = "@(#)strtoul.c  8.1 (Berkeley) 6/4/93";
  40  */
  41
  42 #include <sys/param.h>
  43 #include <sys/systm.h>
  44 #include <sys/ctype.h>
  45 #include <machine/limits.h>
  46
  47 /*
  48  * Note that stdarg.h and the ANSI style va_start macro is used for both
  49  * ANSI and traditional C compilers.
  50  */
  51 #include <machine/stdarg.h>
  52
  53 #define BUF             32      /* Maximum length of numeric string. */
  54
  55 /*
  56  * Flags used during conversion.
  57  */
  58 #define LONG            0x01    /* l: long or double */
  59 #define SHORT           0x04    /* h: short */
  60 #define SUPPRESS        0x08    /* suppress assignment */
  61 #define POINTER         0x10    /* weird %p pointer (`fake hex') */
  62 #define NOSKIP          0x20    /* do not skip blanks */
  63 #define QUAD            0x400
  64
  65 /*
  66  * The following are used in numeric conversions only:
  67  * SIGNOK, NDIGITS, DPTOK, and EXPOK are for floating point;
  68  * SIGNOK, NDIGITS, PFXOK, and NZDIGITS are for integral.
  69  */
  70 #define SIGNOK          0x40    /* +/- is (still) legal */
  71 #define NDIGITS         0x80    /* no digits detected */
  72
  73 #define DPTOK           0x100   /* (float) decimal point is still legal */
  74 #define EXPOK           0x200   /* (float) exponent (e+3, etc) still legal */
  75
  76 #define PFXOK           0x100   /* 0x prefix is (still) legal */
  77 #define NZDIGITS        0x200   /* no zero digits detected */
  78
  79 /*
  80  * Conversion types.
  81  */
  82 #define CT_CHAR         0       /* %c conversion */
  83 #define CT_CCL          1       /* %[...] conversion */
  84 #define CT_STRING       2       /* %s conversion */
  85 #define CT_INT          3       /* integer, i.e., strtoq or strtouq */
  86 typedef u_quad_t (*ccfntype)(const char *, char **, int);
  87
  88 static const u_char *__sccl(char *, const u_char *);
  89
  90 int
  91 sscanf(const char *ibuf, const char *fmt, ...)
  92 {
  93         va_list ap;
  94         int ret;
  95
  96         va_start(ap, fmt);
  97         ret = vsscanf(ibuf, fmt, ap);
  98         va_end(ap);
  99         return(ret);
 100 }
 101
 102 int
 103 vsscanf(const char *inp, char const *fmt0, va_list ap)
 104 {
 105         int inr;
 106         const u_char *fmt = (const u_char *)fmt0;
 107         int c;                  /* character from format, or conversion */
 108         size_t width;           /* field width, or 0 */
 109         char *p;                /* points into all kinds of strings */
 110         int n;                  /* handy integer */
 111         int flags;              /* flags as defined above */
 112         char *p0;               /* saves original value of p when necessary */
 113         int nassigned;          /* number of fields assigned */
 114         int nconversions;       /* number of conversions */
 115         int nread;              /* number of characters consumed from fp */
 116         int base;               /* base argument to strtoq/strtouq */
 117         ccfntype ccfn;          /* conversion function (strtoq/strtouq) */
 118         char ccltab[256];       /* character class table for %[...] */
 119         char buf[BUF];          /* buffer for numeric conversions */
 120
 121         /* `basefix' is used to avoid `if' tests in the integer scanner */
 122         static short basefix[17] =
 123                 { 10, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 };
 124
 125         inr = strlen(inp);
 126
 127         nassigned = 0;
 128         nconversions = 0;
 129         nread = 0;
 130         base = 0;               /* XXX just to keep gcc happy */
 131         ccfn = NULL;            /* XXX just to keep gcc happy */
 132         for (;;) {
 133                 c = *fmt++;
 134                 if (c == 0)
 135                         return (nassigned);
 136                 if (isspace(c)) {
 137                         while (inr > 0 && isspace(*inp))
 138                                 nread++, inr--, inp++;
 139                         continue;
 140                 }
 141                 if (c != '%')
 142                         goto literal;
 143                 width = 0;
 144                 flags = 0;
 145                 /*
 146                  * switch on the format.  continue if done;
 147                  * break once format type is derived.
 148                  */
 149 again:          c = *fmt++;
 150                 switch (c) {
 151                 case '%':
 152 literal:
 153                         if (inr <= 0)
 154                                 goto input_failure;
 155                         if (*inp != c)
 156                                 goto match_failure;
 157                         inr--, inp++;
 158                         nread++;
 159                         continue;
 160
 161                 case '*':
 162                         flags |= SUPPRESS;
 163                         goto again;
 164                 case 'l':
 165                         flags |= LONG;
 166                         goto again;
 167                 case 'q':
 168                         flags |= QUAD;
 169                         goto again;
 170                 case 'h':
 171                         flags |= SHORT;
 172                         goto again;
 173
 174                 case '0': case '1': case '2': case '3': case '4':
 175                 case '5': case '6': case '7': case '8': case '9':
 176                         width = width * 10 + c - '0';
 177                         goto again;
 178
 179                 /*
 180                  * Conversions.
 181                  *
 182                  */
 183                 case 'd':
 184                         c = CT_INT;
 185                         ccfn = (ccfntype)strtoq;
 186                         base = 10;
 187                         break;
 188
 189                 case 'i':
 190                         c = CT_INT;
 191                         ccfn = (ccfntype)strtoq;
 192                         base = 0;
 193                         break;
 194
 195                 case 'o':
 196                         c = CT_INT;
 197                         ccfn = strtouq;
 198                         base = 8;
 199                         break;
 200
 201                 case 'u':
 202                         c = CT_INT;
 203                         ccfn = strtouq;
 204                         base = 10;
 205                         break;
 206
 207                 case 'x':
 208                         flags |= PFXOK; /* enable 0x prefixing */
 209                         c = CT_INT;
 210                         ccfn = strtouq;
 211                         base = 16;
 212                         break;
 213
 214                 case 's':
 215                         c = CT_STRING;
 216                         break;
 217
 218                 case '[':
 219                         fmt = __sccl(ccltab, fmt);
 220                         flags |= NOSKIP;
 221                         c = CT_CCL;
 222                         break;
 223
 224                 case 'c':
 225                         flags |= NOSKIP;
 226                         c = CT_CHAR;
 227                         break;
 228
 229                 case 'p':       /* pointer format is like hex */
 230                         flags |= POINTER | PFXOK;
 231                         c = CT_INT;
 232                         ccfn = strtouq;
 233                         base = 16;
 234                         break;
 235
 236                 case 'n':
 237                         nconversions++;
 238                         if (flags & SUPPRESS)   /* ??? */
 239                                 continue;
 240                         if (flags & SHORT)
 241                                 *va_arg(ap, short *) = nread;
 242                         else if (flags & LONG)
 243                                 *va_arg(ap, long *) = nread;
 244                         else if (flags & QUAD)
 245                                 *va_arg(ap, quad_t *) = nread;
 246                         else
 247                                 *va_arg(ap, int *) = nread;
 248                         continue;
 249                 }
 250
 251                 /*
 252                  * We have a conversion that requires input.
 253                  */
 254                 if (inr <= 0)
 255                         goto input_failure;
 256
 257                 /*
 258                  * Consume leading white space, except for formats
 259                  * that suppress this.
 260                  */
 261                 if ((flags & NOSKIP) == 0) {
 262                         while (isspace(*inp)) {
 263                                 nread++;
 264                                 if (--inr > 0)
 265                                         inp++;
 266                                 else
 267                                         goto input_failure;
 268                         }
 269                         /*
 270                          * Note that there is at least one character in
 271                          * the buffer, so conversions that do not set NOSKIP
 272                          * can no longer result in an input failure.
 273                          */
 274                 }
 275
 276                 /*
 277                  * Do the conversion.
 278                  */
 279                 switch (c) {
 280
 281                 case CT_CHAR:
 282                         /* scan arbitrary characters (sets NOSKIP) */
 283                         if (width == 0)
 284                                 width = 1;
 285                         if (flags & SUPPRESS) {
 286                                 size_t sum = 0;
 287                                 for (;;) {
 288                                         if ((n = inr) < width) {
 289                                                 sum += n;
 290                                                 width -= n;
 291                                                 inp += n;
 292                                                 if (sum == 0)
 293                                                         goto input_failure;
 294                                                         break;
 295                                         } else {
 296                                                 sum += width;
 297                                                 inr -= width;
 298                                                 inp += width;
 299                                                 break;
 300                                         }
 301                                 }
 302                                 nread += sum;
 303                         } else {
 304                                 bcopy(inp, va_arg(ap, char *), width);
 305                                 inr -= width;
 306                                 inp += width;
 307                                 nread += width;
 308                                 nassigned++;
 309                         }
 310                         nconversions++;
 311                         break;
 312
 313                 case CT_CCL:
 314                         /* scan a (nonempty) character class (sets NOSKIP) */
 315                         if (width == 0)
 316                                 width = (size_t)~0;     /* `infinity' */
 317                         /* take only those things in the class */
 318                         if (flags & SUPPRESS) {
 319                                 n = 0;
 320                                 while (ccltab[(unsigned char)*inp]) {
 321                                         n++, inr--, inp++;
 322                                         if (--width == 0)
 323                                                 break;
 324                                         if (inr <= 0) {
 325                                                 if (n == 0)
 326                                                         goto input_failure;
 327                                                 break;
 328                                         }
 329                                 }
 330                                 if (n == 0)
 331                                         goto match_failure;
 332                         } else {
 333                                 p0 = p = va_arg(ap, char *);
 334                                 while (ccltab[(unsigned char)*inp]) {
 335                                         inr--;
 336                                         *p++ = *inp++;
 337                                         if (--width == 0)
 338                                                 break;
 339                                         if (inr <= 0) {
 340                                                 if (p == p0)
 341                                                         goto input_failure;
 342                                                 break;
 343                                         }
 344                                 }
 345                                 n = p - p0;
 346                                 if (n == 0)
 347                                         goto match_failure;
 348                                 *p = 0;
 349                                 nassigned++;
 350                         }
 351                         nread += n;
 352                         nconversions++;
 353                         break;
 354
 355                 case CT_STRING:
 356                         /* like CCL, but zero-length string OK, & no NOSKIP */
 357                         if (width == 0)
 358                                 width = (size_t)~0;
 359                         if (flags & SUPPRESS) {
 360                                 n = 0;
 361                                 while (!isspace(*inp)) {
 362                                         n++, inr--, inp++;
 363                                         if (--width == 0)
 364                                                 break;
 365                                         if (inr <= 0)
 366                                                 break;
 367                                 }
 368                                 nread += n;
 369                         } else {
 370                                 p0 = p = va_arg(ap, char *);
 371                                 while (!isspace(*inp)) {
 372                                         inr--;
 373                                         *p++ = *inp++;
 374                                         if (--width == 0)
 375                                                 break;
 376                                         if (inr <= 0)
 377                                                 break;
 378                                 }
 379                                 *p = 0;
 380                                 nread += p - p0;
 381                                 nassigned++;
 382                         }
 383                         nconversions++;
 384                         continue;
 385
 386                 case CT_INT:
 387                         /* scan an integer as if by strtoq/strtouq */
 388 #ifdef hardway
 389                         if (width == 0 || width > sizeof(buf) - 1)
 390                                 width = sizeof(buf) - 1;
 391 #else
 392                         /* size_t is unsigned, hence this optimisation */
 393                         if (--width > sizeof(buf) - 2)
 394                                 width = sizeof(buf) - 2;
 395                         width++;
 396 #endif
 397                         flags |= SIGNOK | NDIGITS | NZDIGITS;
 398                         for (p = buf; width; width--) {
 399                                 c = *inp;
 400                                 /*
 401                                  * Switch on the character; `goto ok'
 402                                  * if we accept it as a part of number.
 403                                  */
 404                                 switch (c) {
 405
 406                                 /*
 407                                  * The digit 0 is always legal, but is
 408                                  * special.  For %i conversions, if no
 409                                  * digits (zero or nonzero) have been
 410                                  * scanned (only signs), we will have
 411                                  * base==0.  In that case, we should set
 412                                  * it to 8 and enable 0x prefixing.
 413                                  * Also, if we have not scanned zero digits
 414                                  * before this, do not turn off prefixing
 415                                  * (someone else will turn it off if we
 416                                  * have scanned any nonzero digits).
 417                                  */
 418                                 case '0':
 419                                         if (base == 0) {
 420                                                 base = 8;
 421                                                 flags |= PFXOK;
 422                                         }
 423                                         if (flags & NZDIGITS)
 424                                             flags &= ~(SIGNOK|NZDIGITS|NDIGITS);
 425                                         else
 426                                             flags &= ~(SIGNOK|PFXOK|NDIGITS);
 427                                         goto ok;
 428
 429                                 /* 1 through 7 always legal */
 430                                 case '1': case '2': case '3':
 431                                 case '4': case '5': case '6': case '7':
 432                                         base = basefix[base];
 433                                         flags &= ~(SIGNOK | PFXOK | NDIGITS);
 434                                         goto ok;
 435
 436                                 /* digits 8 and 9 ok iff decimal or hex */
 437                                 case '8': case '9':
 438                                         base = basefix[base];
 439                                         if (base <= 8)
 440                                                 break;  /* not legal here */
 441                                         flags &= ~(SIGNOK | PFXOK | NDIGITS);
 442                                         goto ok;
 443
 444                                 /* letters ok iff hex */
 445                                 case 'A': case 'B': case 'C':
 446                                 case 'D': case 'E': case 'F':
 447                                 case 'a': case 'b': case 'c':
 448                                 case 'd': case 'e': case 'f':
 449                                         /* no need to fix base here */
 450                                         if (base <= 10)
 451                                                 break;  /* not legal here */
 452                                         flags &= ~(SIGNOK | PFXOK | NDIGITS);
 453                                         goto ok;
 454
 455                                 /* sign ok only as first character */
 456                                 case '+': case '-':
 457                                         if (flags & SIGNOK) {
 458                                                 flags &= ~SIGNOK;
 459                                                 goto ok;
 460                                         }
 461                                         break;
 462
 463                                 /* x ok iff flag still set & 2nd char */
 464                                 case 'x': case 'X':
 465                                         if (flags & PFXOK && p == buf + 1) {
 466                                                 base = 16;      /* if %i */
 467                                                 flags &= ~PFXOK;
 468                                                 goto ok;
 469                                         }
 470                                         break;
 471                                 }
 472
 473                                 /*
 474                                  * If we got here, c is not a legal character
 475                                  * for a number.  Stop accumulating digits.
 476                                  */
 477                                 break;
 478                 ok:
 479                                 /*
 480                                  * c is legal: store it and look at the next.
 481                                  */
 482                                 *p++ = c;
 483                                 if (--inr > 0)
 484                                         inp++;
 485                                 else
 486                                         break;          /* end of input */
 487                         }
 488                         /*
 489                          * If we had only a sign, it is no good; push
 490                          * back the sign.  If the number ends in `x',
 491                          * it was [sign] '0' 'x', so push back the x
 492                          * and treat it as [sign] '0'.
 493                          */
 494                         if (flags & NDIGITS) {
 495                                 if (p > buf) {
 496                                         inp--;
 497                                         inr++;
 498                                 }
 499                                 goto match_failure;
 500                         }
 501                         c = ((u_char *)p)[-1];
 502                         if (c == 'x' || c == 'X') {
 503                                 --p;
 504                                 inp--;
 505                                 inr++;
 506                         }
 507                         if ((flags & SUPPRESS) == 0) {
 508                                 u_quad_t res;
 509
 510                                 *p = 0;
 511                                 res = (*ccfn)(buf, (char **)NULL, base);
 512                                 if (flags & POINTER)
 513                                         *va_arg(ap, void **) =
 514                                                 (void *)(uintptr_t)res;
 515                                 else if (flags & SHORT)
 516                                         *va_arg(ap, short *) = res;
 517                                 else if (flags & LONG)
 518                                         *va_arg(ap, long *) = res;
 519                                 else if (flags & QUAD)
 520                                         *va_arg(ap, quad_t *) = res;
 521                                 else
 522                                         *va_arg(ap, int *) = res;
 523                                 nassigned++;
 524                         }
 525                         nread += p - buf;
 526                         nconversions++;
 527                         break;
 528
 529                 }
 530         }
 531 input_failure:
 532         return (nconversions != 0 ? nassigned : -1);
 533 match_failure:
 534         return (nassigned);
 535 }
 536
 537 /*
 538  * Fill in the given table from the scanset at the given format
 539  * (just after `[').  Return a pointer to the character past the
 540  * closing `]'.  The table has a 1 wherever characters should be
 541  * considered part of the scanset.
 542  */
 543 static const u_char *
 544 __sccl(char *tab, const u_char *fmt)
 545 {
 546         int c, n, v;
 547
 548         /* first `clear' the whole table */
 549         c = *fmt++;             /* first char hat => negated scanset */
 550         if (c == '^') {
 551                 v = 1;          /* default => accept */
 552                 c = *fmt++;     /* get new first char */
 553         } else
 554                 v = 0;          /* default => reject */
 555
 556         /* XXX: Will not work if sizeof(tab*) > sizeof(char) */
 557         for (n = 0; n < 256; n++)
 558                      tab[n] = v;        /* memset(tab, v, 256) */
 559
 560         if (c == 0)
 561                 return (fmt - 1);/* format ended before closing ] */
 562
 563         /*
 564          * Now set the entries corresponding to the actual scanset
 565          * to the opposite of the above.
 566          *
 567          * The first character may be ']' (or '-') without being special;
 568          * the last character may be '-'.
 569          */
 570         v = 1 - v;
 571         for (;;) {
 572                 tab[c] = v;             /* take character c */
 573 doswitch:
 574                 n = *fmt++;             /* and examine the next */
 575                 switch (n) {
 576
 577                 case 0:                 /* format ended too soon */
 578                         return (fmt - 1);
 579
 580                 case '-':
 581                         /*
 582                          * A scanset of the form
 583                          *      [01+-]
 584                          * is defined as `the digit 0, the digit 1,
 585                          * the character +, the character -', but
 586                          * the effect of a scanset such as
 587                          *      [a-zA-Z0-9]
 588                          * is implementation defined.  The V7 Unix
 589                          * scanf treats `a-z' as `the letters a through
 590                          * z', but treats `a-a' as `the letter a, the
 591                          * character -, and the letter a'.
 592                          *
 593                          * For compatibility, the `-' is not considerd
 594                          * to define a range if the character following
 595                          * it is either a close bracket (required by ANSI)
 596                          * or is not numerically greater than the character
 597                          * we just stored in the table (c).
 598                          */
 599                         n = *fmt;
 600                         if (n == ']' || n < c) {
 601                                 c = '-';
 602                                 break;  /* resume the for(;;) */
 603                         }
 604                         fmt++;
 605                         /* fill in the range */
 606                         do {
 607                             tab[++c] = v;
 608                         } while (c < n);
 609                         c = n;
 610                         /*
 611                          * Alas, the V7 Unix scanf also treats formats
 612                          * such as [a-c-e] as `the letters a through e'.
 613                          * This too is permitted by the standard....
 614                          */
 615                         goto doswitch;
 616                         break;
 617
 618                 case ']':               /* end of scanset */
 619                         return (fmt);
 620
 621                 default:                /* just another character */
 622                         c = n;
 623                         break;
 624                 }
 625         }
 626         /* NOTREACHED */
 627 }
 628