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