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  * $DragonFly: src/sys/kern/subr_scanf.c,v 1.4 2006/12/13 21:58:50 dillon Exp $
  38  * From: Id: vfscanf.c,v 1.13 1998/09/25 12:20:27 obrien Exp
  39  * From: static char sccsid[] = "@(#)strtol.c   8.1 (Berkeley) 6/4/93";
  40  * From: static char sccsid[] = "@(#)strtoul.c  8.1 (Berkeley) 6/4/93";
  41  */
  42
  43 #include <sys/param.h>
  44 #include <sys/systm.h>
  45 #include <sys/ctype.h>
  46 #include <machine/limits.h>
  47
  48 /*
  49  * Note that stdarg.h and the ANSI style va_start macro is used for both
  50  * ANSI and traditional C compilers.
  51  */
  52 #include <machine/stdarg.h>
  53
  54 #define BUF             32      /* Maximum length of numeric string. */
  55
  56 /*
  57  * Flags used during conversion.
  58  */
  59 #define LONG            0x01    /* l: long or double */
  60 #define SHORT           0x04    /* h: short */
  61 #define SUPPRESS        0x08    /* suppress assignment */
  62 #define POINTER         0x10    /* weird %p pointer (`fake hex') */
  63 #define NOSKIP          0x20    /* do not skip blanks */
  64 #define QUAD            0x400
  65
  66 /*
  67  * The following are used in numeric conversions only:
  68  * SIGNOK, NDIGITS, DPTOK, and EXPOK are for floating point;
  69  * SIGNOK, NDIGITS, PFXOK, and NZDIGITS are for integral.
  70  */
  71 #define SIGNOK          0x40    /* +/- is (still) legal */
  72 #define NDIGITS         0x80    /* no digits detected */
  73
  74 #define DPTOK           0x100   /* (float) decimal point is still legal */
  75 #define EXPOK           0x200   /* (float) exponent (e+3, etc) still legal */
  76
  77 #define PFXOK           0x100   /* 0x prefix is (still) legal */
  78 #define NZDIGITS        0x200   /* no zero digits detected */
  79
  80 /*
  81  * Conversion types.
  82  */
  83 #define CT_CHAR         0       /* %c conversion */
  84 #define CT_CCL          1       /* %[...] conversion */
  85 #define CT_STRING       2       /* %s conversion */
  86 #define CT_INT          3       /* integer, i.e., strtoq or strtouq */
  87 typedef u_quad_t (*ccfntype)(const char *, char **, int);
  88
  89 static const u_char *__sccl(char *, const u_char *);
  90
  91 int
  92 ksscanf(const char *ibuf, const char *fmt, ...)
  93 {
  94         __va_list ap;
  95         int ret;
  96
  97         __va_start(ap, fmt);
  98         ret = kvsscanf(ibuf, fmt, ap);
  99         __va_end(ap);
 100         return(ret);
 101 }
 102
 103 int
 104 kvsscanf(const char *inp, char const *fmt0, __va_list ap)
 105 {
 106         int inr;
 107         const u_char *fmt = (const u_char *)fmt0;
 108         int c;                  /* character from format, or conversion */
 109         size_t width;           /* field width, or 0 */
 110         char *p;                /* points into all kinds of strings */
 111         int n;                  /* handy integer */
 112         int flags;              /* flags as defined above */
 113         char *p0;               /* saves original value of p when necessary */
 114         int nassigned;          /* number of fields assigned */
 115         int nconversions;       /* number of conversions */
 116         int nread;              /* number of characters consumed from fp */
 117         int base;               /* base argument to strtoq/strtouq */
 118         ccfntype ccfn;          /* conversion function (strtoq/strtouq) */
 119         char ccltab[256];       /* character class table for %[...] */
 120         char buf[BUF];          /* buffer for numeric conversions */
 121
 122         /* `basefix' is used to avoid `if' tests in the integer scanner */
 123         static short basefix[17] =
 124                 { 10, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 };
 125
 126         inr = strlen(inp);
 127
 128         nassigned = 0;
 129         nconversions = 0;
 130         nread = 0;
 131         base = 0;               /* XXX just to keep gcc happy */
 132         ccfn = NULL;            /* XXX just to keep gcc happy */
 133         for (;;) {
 134                 c = *fmt++;
 135                 if (c == 0)
 136                         return (nassigned);
 137                 if (isspace(c)) {
 138                         while (inr > 0 && isspace(*inp))
 139                                 nread++, inr--, inp++;
 140                         continue;
 141                 }
 142                 if (c != '%')
 143                         goto literal;
 144                 width = 0;
 145                 flags = 0;
 146                 /*
 147                  * switch on the format.  continue if done;
 148                  * break once format type is derived.
 149                  */
 150 again:          c = *fmt++;
 151                 switch (c) {
 152                 case '%':
 153 literal:
 154                         if (inr <= 0)
 155                                 goto input_failure;
 156                         if (*inp != c)
 157                                 goto match_failure;
 158                         inr--, inp++;
 159                         nread++;
 160                         continue;
 161
 162                 case '*':
 163                         flags |= SUPPRESS;
 164                         goto again;
 165                 case 'l':
 166                         flags |= LONG;
 167                         goto again;
 168                 case 'q':
 169                         flags |= QUAD;
 170                         goto again;
 171                 case 'h':
 172                         flags |= SHORT;
 173                         goto again;
 174
 175                 case '0': case '1': case '2': case '3': case '4':
 176                 case '5': case '6': case '7': case '8': case '9':
 177                         width = width * 10 + c - '0';
 178                         goto again;
 179
 180                 /*
 181                  * Conversions.
 182                  *
 183                  */
 184                 case 'd':
 185                         c = CT_INT;
 186                         ccfn = (ccfntype)strtoq;
 187                         base = 10;
 188                         break;
 189
 190                 case 'i':
 191                         c = CT_INT;
 192                         ccfn = (ccfntype)strtoq;
 193                         base = 0;
 194                         break;
 195
 196                 case 'o':
 197                         c = CT_INT;
 198                         ccfn = strtouq;
 199                         base = 8;
 200                         break;
 201
 202                 case 'u':
 203                         c = CT_INT;
 204                         ccfn = strtouq;
 205                         base = 10;
 206                         break;
 207
 208                 case 'x':
 209                         flags |= PFXOK; /* enable 0x prefixing */
 210                         c = CT_INT;
 211                         ccfn = strtouq;
 212                         base = 16;
 213                         break;
 214
 215                 case 's':
 216                         c = CT_STRING;
 217                         break;
 218
 219                 case '[':
 220                         fmt = __sccl(ccltab, fmt);
 221                         flags |= NOSKIP;
 222                         c = CT_CCL;
 223                         break;
 224
 225                 case 'c':
 226                         flags |= NOSKIP;
 227                         c = CT_CHAR;
 228                         break;
 229
 230                 case 'p':       /* pointer format is like hex */
 231                         flags |= POINTER | PFXOK;
 232                         c = CT_INT;
 233                         ccfn = strtouq;
 234                         base = 16;
 235                         break;
 236
 237                 case 'n':
 238                         nconversions++;
 239                         if (flags & SUPPRESS)   /* ??? */
 240                                 continue;
 241                         if (flags & SHORT)
 242                                 *__va_arg(ap, short *) = nread;
 243                         else if (flags & LONG)
 244                                 *__va_arg(ap, long *) = nread;
 245                         else if (flags & QUAD)
 246                                 *__va_arg(ap, quad_t *) = nread;
 247                         else
 248                                 *__va_arg(ap, int *) = nread;
 249                         continue;
 250                 }
 251
 252                 /*
 253                  * We have a conversion that requires input.
 254                  */
 255                 if (inr <= 0)
 256                         goto input_failure;
 257
 258                 /*
 259                  * Consume leading white space, except for formats
 260                  * that suppress this.
 261                  */
 262                 if ((flags & NOSKIP) == 0) {
 263                         while (isspace(*inp)) {
 264                                 nread++;
 265                                 if (--inr > 0)
 266                                         inp++;
 267                                 else
 268                                         goto input_failure;
 269                         }
 270                         /*
 271                          * Note that there is at least one character in
 272                          * the buffer, so conversions that do not set NOSKIP
 273                          * can no longer result in an input failure.
 274                          */
 275                 }
 276
 277                 /*
 278                  * Do the conversion.
 279                  */
 280                 switch (c) {
 281
 282                 case CT_CHAR:
 283                         /* scan arbitrary characters (sets NOSKIP) */
 284                         if (width == 0)
 285                                 width = 1;
 286                         if (flags & SUPPRESS) {
 287                                 size_t sum = 0;
 288                                 for (;;) {
 289                                         if ((n = inr) < width) {
 290                                                 sum += n;
 291                                                 width -= n;
 292                                                 inp += n;
 293                                                 if (sum == 0)
 294                                                         goto input_failure;
 295                                                 break;
 296                                         } else {
 297                                                 sum += width;
 298                                                 inr -= width;
 299                                                 inp += width;
 300                                                 break;
 301                                         }
 302                                 }
 303                                 nread += sum;
 304                         } else {
 305                                 bcopy(inp, __va_arg(ap, char *), width);
 306                                 inr -= width;
 307                                 inp += width;
 308                                 nread += width;
 309                                 nassigned++;
 310                         }
 311                         nconversions++;
 312                         break;
 313
 314                 case CT_CCL:
 315                         /* scan a (nonempty) character class (sets NOSKIP) */
 316                         if (width == 0)
 317                                 width = (size_t)~0;     /* `infinity' */
 318                         /* take only those things in the class */
 319                         if (flags & SUPPRESS) {
 320                                 n = 0;
 321                                 while (ccltab[(unsigned char)*inp]) {
 322                                         n++, inr--, inp++;
 323                                         if (--width == 0)
 324                                                 break;
 325                                         if (inr <= 0) {
 326                                                 if (n == 0)
 327                                                         goto input_failure;
 328                                                 break;
 329                                         }
 330                                 }
 331                                 if (n == 0)
 332                                         goto match_failure;
 333                         } else {
 334                                 p0 = p = __va_arg(ap, char *);
 335                                 while (ccltab[(unsigned char)*inp]) {
 336                                         inr--;
 337                                         *p++ = *inp++;
 338                                         if (--width == 0)
 339                                                 break;
 340                                         if (inr <= 0) {
 341                                                 if (p == p0)
 342                                                         goto input_failure;
 343                                                 break;
 344                                         }
 345                                 }
 346                                 n = p - p0;
 347                                 if (n == 0)
 348                                         goto match_failure;
 349                                 *p = 0;
 350                                 nassigned++;
 351                         }
 352                         nread += n;
 353                         nconversions++;
 354                         break;
 355
 356                 case CT_STRING:
 357                         /* like CCL, but zero-length string OK, & no NOSKIP */
 358                         if (width == 0)
 359                                 width = (size_t)~0;
 360                         if (flags & SUPPRESS) {
 361                                 n = 0;
 362                                 while (!isspace(*inp)) {
 363                                         n++, inr--, inp++;
 364                                         if (--width == 0)
 365                                                 break;
 366                                         if (inr <= 0)
 367                                                 break;
 368                                 }
 369                                 nread += n;
 370                         } else {
 371                                 p0 = p = __va_arg(ap, char *);
 372                                 while (!isspace(*inp)) {
 373                                         inr--;
 374                                         *p++ = *inp++;
 375                                         if (--width == 0)
 376                                                 break;
 377                                         if (inr <= 0)
 378                                                 break;
 379                                 }
 380                                 *p = 0;
 381                                 nread += p - p0;
 382                                 nassigned++;
 383                         }
 384                         nconversions++;
 385                         continue;
 386
 387                 case CT_INT:
 388                         /* scan an integer as if by strtoq/strtouq */
 389 #ifdef hardway
 390                         if (width == 0 || width > sizeof(buf) - 1)
 391                                 width = sizeof(buf) - 1;
 392 #else
 393                         /* size_t is unsigned, hence this optimisation */
 394                         if (--width > sizeof(buf) - 2)
 395                                 width = sizeof(buf) - 2;
 396                         width++;
 397 #endif
 398                         flags |= SIGNOK | NDIGITS | NZDIGITS;
 399                         for (p = buf; width; width--) {
 400                                 c = *inp;
 401                                 /*
 402                                  * Switch on the character; `goto ok'
 403                                  * if we accept it as a part of number.
 404                                  */
 405                                 switch (c) {
 406
 407                                 /*
 408                                  * The digit 0 is always legal, but is
 409                                  * special.  For %i conversions, if no
 410                                  * digits (zero or nonzero) have been
 411                                  * scanned (only signs), we will have
 412                                  * base==0.  In that case, we should set
 413                                  * it to 8 and enable 0x prefixing.
 414                                  * Also, if we have not scanned zero digits
 415                                  * before this, do not turn off prefixing
 416                                  * (someone else will turn it off if we
 417                                  * have scanned any nonzero digits).
 418                                  */
 419                                 case '0':
 420                                         if (base == 0) {
 421                                                 base = 8;
 422                                                 flags |= PFXOK;
 423                                         }
 424                                         if (flags & NZDIGITS)
 425                                             flags &= ~(SIGNOK|NZDIGITS|NDIGITS);
 426                                         else
 427                                             flags &= ~(SIGNOK|PFXOK|NDIGITS);
 428                                         goto ok;
 429
 430                                 /* 1 through 7 always legal */
 431                                 case '1': case '2': case '3':
 432                                 case '4': case '5': case '6': case '7':
 433                                         base = basefix[base];
 434                                         flags &= ~(SIGNOK | PFXOK | NDIGITS);
 435                                         goto ok;
 436
 437                                 /* digits 8 and 9 ok iff decimal or hex */
 438                                 case '8': case '9':
 439                                         base = basefix[base];
 440                                         if (base <= 8)
 441                                                 break;  /* not legal here */
 442                                         flags &= ~(SIGNOK | PFXOK | NDIGITS);
 443                                         goto ok;
 444
 445                                 /* letters ok iff hex */
 446                                 case 'A': case 'B': case 'C':
 447                                 case 'D': case 'E': case 'F':
 448                                 case 'a': case 'b': case 'c':
 449                                 case 'd': case 'e': case 'f':
 450                                         /* no need to fix base here */
 451                                         if (base <= 10)
 452                                                 break;  /* not legal here */
 453                                         flags &= ~(SIGNOK | PFXOK | NDIGITS);
 454                                         goto ok;
 455
 456                                 /* sign ok only as first character */
 457                                 case '+': case '-':
 458                                         if (flags & SIGNOK) {
 459                                                 flags &= ~SIGNOK;
 460                                                 goto ok;
 461                                         }
 462                                         break;
 463
 464                                 /* x ok iff flag still set & 2nd char */
 465                                 case 'x': case 'X':
 466                                         if (flags & PFXOK && p == buf + 1) {
 467                                                 base = 16;      /* if %i */
 468                                                 flags &= ~PFXOK;
 469                                                 goto ok;
 470                                         }
 471                                         break;
 472                                 }
 473
 474                                 /*
 475                                  * If we got here, c is not a legal character
 476                                  * for a number.  Stop accumulating digits.
 477                                  */
 478                                 break;
 479                 ok:
 480                                 /*
 481                                  * c is legal: store it and look at the next.
 482                                  */
 483                                 *p++ = c;
 484                                 if (--inr > 0)
 485                                         inp++;
 486                                 else
 487                                         break;          /* end of input */
 488                         }
 489                         /*
 490                          * If we had only a sign, it is no good; push
 491                          * back the sign.  If the number ends in `x',
 492                          * it was [sign] '0' 'x', so push back the x
 493                          * and treat it as [sign] '0'.
 494                          */
 495                         if (flags & NDIGITS) {
 496                                 if (p > buf) {
 497                                         inp--;
 498                                         inr++;
 499                                 }
 500                                 goto match_failure;
 501                         }
 502                         c = ((u_char *)p)[-1];
 503                         if (c == 'x' || c == 'X') {
 504                                 --p;
 505                                 inp--;
 506                                 inr++;
 507                         }
 508                         if ((flags & SUPPRESS) == 0) {
 509                                 u_quad_t res;
 510
 511                                 *p = 0;
 512                                 res = (*ccfn)(buf, NULL, base);
 513                                 if (flags & POINTER)
 514                                         *__va_arg(ap, void **) =
 515                                                 (void *)(uintptr_t)res;
 516                                 else if (flags & SHORT)
 517                                         *__va_arg(ap, short *) = res;
 518                                 else if (flags & LONG)
 519                                         *__va_arg(ap, long *) = res;
 520                                 else if (flags & QUAD)
 521                                         *__va_arg(ap, quad_t *) = res;
 522                                 else
 523                                         *__va_arg(ap, int *) = res;
 524                                 nassigned++;
 525                         }
 526                         nread += p - buf;
 527                         nconversions++;
 528                         break;
 529
 530                 }
 531         }
 532 input_failure:
 533         return (nconversions != 0 ? nassigned : -1);
 534 match_failure:
 535         return (nassigned);
 536 }
 537
 538 /*
 539  * Fill in the given table from the scanset at the given format
 540  * (just after `[').  Return a pointer to the character past the
 541  * closing `]'.  The table has a 1 wherever characters should be
 542  * considered part of the scanset.
 543  */
 544 static const u_char *
 545 __sccl(char *tab, const u_char *fmt)
 546 {
 547         int c, n, v;
 548
 549         /* first `clear' the whole table */
 550         c = *fmt++;             /* first char hat => negated scanset */
 551         if (c == '^') {
 552                 v = 1;          /* default => accept */
 553                 c = *fmt++;     /* get new first char */
 554         } else
 555                 v = 0;          /* default => reject */
 556
 557         /* XXX: Will not work if sizeof(tab*) > sizeof(char) */
 558         for (n = 0; n < 256; n++)
 559                      tab[n] = v;        /* memset(tab, v, 256) */
 560
 561         if (c == 0)
 562                 return (fmt - 1);/* format ended before closing ] */
 563
 564         /*
 565          * Now set the entries corresponding to the actual scanset
 566          * to the opposite of the above.
 567          *
 568          * The first character may be ']' (or '-') without being special;
 569          * the last character may be '-'.
 570          */
 571         v = 1 - v;
 572         for (;;) {
 573                 tab[c] = v;             /* take character c */
 574 doswitch:
 575                 n = *fmt++;             /* and examine the next */
 576                 switch (n) {
 577
 578                 case 0:                 /* format ended too soon */
 579                         return (fmt - 1);
 580
 581                 case '-':
 582                         /*
 583                          * A scanset of the form
 584                          *      [01+-]
 585                          * is defined as `the digit 0, the digit 1,
 586                          * the character +, the character -', but
 587                          * the effect of a scanset such as
 588                          *      [a-zA-Z0-9]
 589                          * is implementation defined.  The V7 Unix
 590                          * scanf treats `a-z' as `the letters a through
 591                          * z', but treats `a-a' as `the letter a, the
 592                          * character -, and the letter a'.
 593                          *
 594                          * For compatibility, the `-' is not considerd
 595                          * to define a range if the character following
 596                          * it is either a close bracket (required by ANSI)
 597                          * or is not numerically greater than the character
 598                          * we just stored in the table (c).
 599                          */
 600                         n = *fmt;
 601                         if (n == ']' || n < c) {
 602                                 c = '-';
 603                                 break;  /* resume the for(;;) */
 604                         }
 605                         fmt++;
 606                         /* fill in the range */
 607                         do {
 608                             tab[++c] = v;
 609                         } while (c < n);
 610                         c = n;
 611                         /*
 612                          * Alas, the V7 Unix scanf also treats formats
 613                          * such as [a-c-e] as `the letters a through e'.
 614                          * This too is permitted by the standard....
 615                          */
 616                         goto doswitch;
 617                         break;
 618
 619                 case ']':               /* end of scanset */
 620                         return (fmt);
 621
 622                 default:                /* just another character */
 623                         c = n;
 624                         break;
 625                 }
 626         }
 627         /* NOTREACHED */
 628 }
 629