sys/kern/subr_scanf.c

   1 /*-
   2  * SPDX-License-Identifier: BSD-3-Clause
   3  *
   4  * Copyright (c) 1990, 1993
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * This code is derived from software contributed to Berkeley by
   8  * Chris Torek.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  * 3. Neither the name of the University nor the names of its contributors
  19  *    may be used to endorse or promote products derived from this software
  20  *    without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  *
  34  * From: Id: vfscanf.c,v 1.13 1998/09/25 12:20:27 obrien Exp
  35  */
  36
  37 #include <sys/param.h>
  38 #include <sys/systm.h>
  39 #include <sys/ctype.h>
  40 #include <sys/limits.h>
  41 #include <sys/stddef.h>
  42
  43 /*
  44  * Note that stdarg.h and the ANSI style va_start macro is used for both
  45  * ANSI and traditional C compilers.
  46  */
  47 #include <machine/stdarg.h>
  48
  49 #define BUF             32      /* Maximum length of numeric string. */
  50
  51 /*
  52  * Flags used during conversion.
  53  */
  54 #define LONG            0x01    /* l: long or double */
  55 #define SHORT           0x04    /* h: short */
  56 #define SUPPRESS        0x08    /* suppress assignment */
  57 #define POINTER         0x10    /* weird %p pointer (`fake hex') */
  58 #define NOSKIP          0x20    /* do not skip blanks */
  59 #define QUAD            0x400
  60 #define INTMAXT         0x800   /* j: intmax_t */
  61 #define PTRDIFFT        0x1000  /* t: ptrdiff_t */
  62 #define SIZET           0x2000  /* z: size_t */
  63 #define SHORTSHORT      0x4000  /** hh: char */
  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 'j':
 165                         flags |= INTMAXT;
 166                         goto again;
 167                 case 'l':
 168                         if (flags & LONG){
 169                                 flags &= ~LONG;
 170                                 flags |= QUAD;
 171                         } else {
 172                                 flags |= LONG;
 173                         }
 174                         goto again;
 175                 case 'q':
 176                         flags |= QUAD;
 177                         goto again;
 178                 case 't':
 179                         flags |= PTRDIFFT;
 180                         goto again;
 181                 case 'z':
 182                         flags |= SIZET;
 183                         goto again;
 184                 case 'h':
 185                         if (flags & SHORT){
 186                                 flags &= ~SHORT;
 187                                 flags |= SHORTSHORT;
 188                         } else {
 189                                 flags |= SHORT;
 190                         }
 191                         goto again;
 192
 193                 case '0': case '1': case '2': case '3': case '4':
 194                 case '5': case '6': case '7': case '8': case '9':
 195                         width = width * 10 + c - '0';
 196                         goto again;
 197
 198                 /*
 199                  * Conversions.
 200                  *
 201                  */
 202                 case 'd':
 203                         c = CT_INT;
 204                         ccfn = (ccfntype)strtoq;
 205                         base = 10;
 206                         break;
 207
 208                 case 'i':
 209                         c = CT_INT;
 210                         ccfn = (ccfntype)strtoq;
 211                         base = 0;
 212                         break;
 213
 214                 case 'o':
 215                         c = CT_INT;
 216                         ccfn = strtouq;
 217                         base = 8;
 218                         break;
 219
 220                 case 'u':
 221                         c = CT_INT;
 222                         ccfn = strtouq;
 223                         base = 10;
 224                         break;
 225
 226                 case 'x':
 227                         flags |= PFXOK; /* enable 0x prefixing */
 228                         c = CT_INT;
 229                         ccfn = strtouq;
 230                         base = 16;
 231                         break;
 232
 233                 case 's':
 234                         c = CT_STRING;
 235                         break;
 236
 237                 case '[':
 238                         fmt = __sccl(ccltab, fmt);
 239                         flags |= NOSKIP;
 240                         c = CT_CCL;
 241                         break;
 242
 243                 case 'c':
 244                         flags |= NOSKIP;
 245                         c = CT_CHAR;
 246                         break;
 247
 248                 case 'p':       /* pointer format is like hex */
 249                         flags |= POINTER | PFXOK;
 250                         c = CT_INT;
 251                         ccfn = strtouq;
 252                         base = 16;
 253                         break;
 254
 255                 case 'n':
 256                         nconversions++;
 257                         if (flags & SUPPRESS)   /* ??? */
 258                                 continue;
 259                         if (flags & SHORTSHORT)
 260                                 *va_arg(ap, char *) = nread;
 261                         else if (flags & SHORT)
 262                                 *va_arg(ap, short *) = nread;
 263                         else if (flags & LONG)
 264                                 *va_arg(ap, long *) = nread;
 265                         else if (flags & QUAD)
 266                                 *va_arg(ap, quad_t *) = nread;
 267                         else if (flags & INTMAXT)
 268                                 *va_arg(ap, intmax_t *) = nread;
 269                         else if (flags & SIZET)
 270                                 *va_arg(ap, size_t *) = nread;
 271                         else if (flags & PTRDIFFT)
 272                                 *va_arg(ap, ptrdiff_t *) = nread;
 273                         else
 274                                 *va_arg(ap, int *) = nread;
 275                         continue;
 276                 }
 277
 278                 /*
 279                  * We have a conversion that requires input.
 280                  */
 281                 if (inr <= 0)
 282                         goto input_failure;
 283
 284                 /*
 285                  * Consume leading white space, except for formats
 286                  * that suppress this.
 287                  */
 288                 if ((flags & NOSKIP) == 0) {
 289                         while (isspace(*inp)) {
 290                                 nread++;
 291                                 if (--inr > 0)
 292                                         inp++;
 293                                 else
 294                                         goto input_failure;
 295                         }
 296                         /*
 297                          * Note that there is at least one character in
 298                          * the buffer, so conversions that do not set NOSKIP
 299                          * can no longer result in an input failure.
 300                          */
 301                 }
 302
 303                 /*
 304                  * Do the conversion.
 305                  */
 306                 switch (c) {
 307                 case CT_CHAR:
 308                         /* scan arbitrary characters (sets NOSKIP) */
 309                         if (width == 0)
 310                                 width = 1;
 311                         if (flags & SUPPRESS) {
 312                                 size_t sum = 0;
 313                                 for (;;) {
 314                                         if ((n = inr) < width) {
 315                                                 sum += n;
 316                                                 width -= n;
 317                                                 inp += n;
 318                                                 if (sum == 0)
 319                                                         goto input_failure;
 320                                                 break;
 321                                         } else {
 322                                                 sum += width;
 323                                                 inr -= width;
 324                                                 inp += width;
 325                                                 break;
 326                                         }
 327                                 }
 328                                 nread += sum;
 329                         } else {
 330                                 bcopy(inp, va_arg(ap, char *), width);
 331                                 inr -= width;
 332                                 inp += width;
 333                                 nread += width;
 334                                 nassigned++;
 335                         }
 336                         nconversions++;
 337                         break;
 338
 339                 case CT_CCL:
 340                         /* scan a (nonempty) character class (sets NOSKIP) */
 341                         if (width == 0)
 342                                 width = (size_t)~0;     /* `infinity' */
 343                         /* take only those things in the class */
 344                         if (flags & SUPPRESS) {
 345                                 n = 0;
 346                                 while (ccltab[(unsigned char)*inp]) {
 347                                         n++, inr--, inp++;
 348                                         if (--width == 0)
 349                                                 break;
 350                                         if (inr <= 0) {
 351                                                 if (n == 0)
 352                                                         goto input_failure;
 353                                                 break;
 354                                         }
 355                                 }
 356                                 if (n == 0)
 357                                         goto match_failure;
 358                         } else {
 359                                 p0 = p = va_arg(ap, char *);
 360                                 while (ccltab[(unsigned char)*inp]) {
 361                                         inr--;
 362                                         *p++ = *inp++;
 363                                         if (--width == 0)
 364                                                 break;
 365                                         if (inr <= 0) {
 366                                                 if (p == p0)
 367                                                         goto input_failure;
 368                                                 break;
 369                                         }
 370                                 }
 371                                 n = p - p0;
 372                                 if (n == 0)
 373                                         goto match_failure;
 374                                 *p = 0;
 375                                 nassigned++;
 376                         }
 377                         nread += n;
 378                         nconversions++;
 379                         break;
 380
 381                 case CT_STRING:
 382                         /* like CCL, but zero-length string OK, & no NOSKIP */
 383                         if (width == 0)
 384                                 width = (size_t)~0;
 385                         if (flags & SUPPRESS) {
 386                                 n = 0;
 387                                 while (!isspace(*inp)) {
 388                                         n++, inr--, inp++;
 389                                         if (--width == 0)
 390                                                 break;
 391                                         if (inr <= 0)
 392                                                 break;
 393                                 }
 394                                 nread += n;
 395                         } else {
 396                                 p0 = p = va_arg(ap, char *);
 397                                 while (!isspace(*inp)) {
 398                                         inr--;
 399                                         *p++ = *inp++;
 400                                         if (--width == 0)
 401                                                 break;
 402                                         if (inr <= 0)
 403                                                 break;
 404                                 }
 405                                 *p = 0;
 406                                 nread += p - p0;
 407                                 nassigned++;
 408                         }
 409                         nconversions++;
 410                         continue;
 411
 412                 case CT_INT:
 413                         /* scan an integer as if by strtoq/strtouq */
 414 #ifdef hardway
 415                         if (width == 0 || width > sizeof(buf) - 1)
 416                                 width = sizeof(buf) - 1;
 417 #else
 418                         /* size_t is unsigned, hence this optimisation */
 419                         if (--width > sizeof(buf) - 2)
 420                                 width = sizeof(buf) - 2;
 421                         width++;
 422 #endif
 423                         flags |= SIGNOK | NDIGITS | NZDIGITS;
 424                         for (p = buf; width; width--) {
 425                                 c = *inp;
 426                                 /*
 427                                  * Switch on the character; `goto ok'
 428                                  * if we accept it as a part of number.
 429                                  */
 430                                 switch (c) {
 431                                 /*
 432                                  * The digit 0 is always legal, but is
 433                                  * special.  For %i conversions, if no
 434                                  * digits (zero or nonzero) have been
 435                                  * scanned (only signs), we will have
 436                                  * base==0.  In that case, we should set
 437                                  * it to 8 and enable 0x prefixing.
 438                                  * Also, if we have not scanned zero digits
 439                                  * before this, do not turn off prefixing
 440                                  * (someone else will turn it off if we
 441                                  * have scanned any nonzero digits).
 442                                  */
 443                                 case '0':
 444                                         if (base == 0) {
 445                                                 base = 8;
 446                                                 flags |= PFXOK;
 447                                         }
 448                                         if (flags & NZDIGITS)
 449                                             flags &= ~(SIGNOK|NZDIGITS|NDIGITS);
 450                                         else
 451                                             flags &= ~(SIGNOK|PFXOK|NDIGITS);
 452                                         goto ok;
 453
 454                                 /* 1 through 7 always legal */
 455                                 case '1': case '2': case '3':
 456                                 case '4': case '5': case '6': case '7':
 457                                         base = basefix[base];
 458                                         flags &= ~(SIGNOK | PFXOK | NDIGITS);
 459                                         goto ok;
 460
 461                                 /* digits 8 and 9 ok iff decimal or hex */
 462                                 case '8': case '9':
 463                                         base = basefix[base];
 464                                         if (base <= 8)
 465                                                 break;  /* not legal here */
 466                                         flags &= ~(SIGNOK | PFXOK | NDIGITS);
 467                                         goto ok;
 468
 469                                 /* letters ok iff hex */
 470                                 case 'A': case 'B': case 'C':
 471                                 case 'D': case 'E': case 'F':
 472                                 case 'a': case 'b': case 'c':
 473                                 case 'd': case 'e': case 'f':
 474                                         /* no need to fix base here */
 475                                         if (base <= 10)
 476                                                 break;  /* not legal here */
 477                                         flags &= ~(SIGNOK | PFXOK | NDIGITS);
 478                                         goto ok;
 479
 480                                 /* sign ok only as first character */
 481                                 case '+': case '-':
 482                                         if (flags & SIGNOK) {
 483                                                 flags &= ~SIGNOK;
 484                                                 goto ok;
 485                                         }
 486                                         break;
 487
 488                                 /* x ok iff flag still set & 2nd char */
 489                                 case 'x': case 'X':
 490                                         if (flags & PFXOK && p == buf + 1) {
 491                                                 base = 16;      /* if %i */
 492                                                 flags &= ~PFXOK;
 493                                                 goto ok;
 494                                         }
 495                                         break;
 496                                 }
 497
 498                                 /*
 499                                  * If we got here, c is not a legal character
 500                                  * for a number.  Stop accumulating digits.
 501                                  */
 502                                 break;
 503                 ok:
 504                                 /*
 505                                  * c is legal: store it and look at the next.
 506                                  */
 507                                 *p++ = c;
 508                                 if (--inr > 0)
 509                                         inp++;
 510                                 else
 511                                         break;          /* end of input */
 512                         }
 513                         /*
 514                          * If we had only a sign, it is no good; push
 515                          * back the sign.  If the number ends in `x',
 516                          * it was [sign] '0' 'x', so push back the x
 517                          * and treat it as [sign] '0'.
 518                          */
 519                         if (flags & NDIGITS) {
 520                                 if (p > buf) {
 521                                         inp--;
 522                                         inr++;
 523                                 }
 524                                 goto match_failure;
 525                         }
 526                         c = ((u_char *)p)[-1];
 527                         if (c == 'x' || c == 'X') {
 528                                 --p;
 529                                 inp--;
 530                                 inr++;
 531                         }
 532                         if ((flags & SUPPRESS) == 0) {
 533                                 u_quad_t res;
 534
 535                                 *p = 0;
 536                                 res = (*ccfn)(buf, (char **)NULL, base);
 537                                 if (flags & POINTER)
 538                                         *va_arg(ap, void **) =
 539                                                 (void *)(uintptr_t)res;
 540                                 else if (flags & SHORTSHORT)
 541                                         *va_arg(ap, char *) = res;
 542                                 else if (flags & SHORT)
 543                                         *va_arg(ap, short *) = res;
 544                                 else if (flags & LONG)
 545                                         *va_arg(ap, long *) = res;
 546                                 else if (flags & QUAD)
 547                                         *va_arg(ap, quad_t *) = res;
 548                                 else if (flags & INTMAXT)
 549                                         *va_arg(ap, intmax_t *) = res;
 550                                 else if (flags & PTRDIFFT)
 551                                         *va_arg(ap, ptrdiff_t *) = res;
 552                                 else if (flags & SIZET)
 553                                         *va_arg(ap, size_t *) = res;
 554                                 else
 555                                         *va_arg(ap, int *) = res;
 556                                 nassigned++;
 557                         }
 558                         nread += p - buf;
 559                         nconversions++;
 560                         break;
 561                 }
 562         }
 563 input_failure:
 564         return (nconversions != 0 ? nassigned : -1);
 565 match_failure:
 566         return (nassigned);
 567 }
 568
 569 /*
 570  * Fill in the given table from the scanset at the given format
 571  * (just after `[').  Return a pointer to the character past the
 572  * closing `]'.  The table has a 1 wherever characters should be
 573  * considered part of the scanset.
 574  */
 575 static const u_char *
 576 __sccl(char *tab, const u_char *fmt)
 577 {
 578         int c, n, v;
 579
 580         /* first `clear' the whole table */
 581         c = *fmt++;             /* first char hat => negated scanset */
 582         if (c == '^') {
 583                 v = 1;          /* default => accept */
 584                 c = *fmt++;     /* get new first char */
 585         } else
 586                 v = 0;          /* default => reject */
 587
 588         /* XXX: Will not work if sizeof(tab*) > sizeof(char) */
 589         for (n = 0; n < 256; n++)
 590                      tab[n] = v;        /* memset(tab, v, 256) */
 591
 592         if (c == 0)
 593                 return (fmt - 1);/* format ended before closing ] */
 594
 595         /*
 596          * Now set the entries corresponding to the actual scanset
 597          * to the opposite of the above.
 598          *
 599          * The first character may be ']' (or '-') without being special;
 600          * the last character may be '-'.
 601          */
 602         v = 1 - v;
 603         for (;;) {
 604                 tab[c] = v;             /* take character c */
 605 doswitch:
 606                 n = *fmt++;             /* and examine the next */
 607                 switch (n) {
 608                 case 0:                 /* format ended too soon */
 609                         return (fmt - 1);
 610
 611                 case '-':
 612                         /*
 613                          * A scanset of the form
 614                          *      [01+-]
 615                          * is defined as `the digit 0, the digit 1,
 616                          * the character +, the character -', but
 617                          * the effect of a scanset such as
 618                          *      [a-zA-Z0-9]
 619                          * is implementation defined.  The V7 Unix
 620                          * scanf treats `a-z' as `the letters a through
 621                          * z', but treats `a-a' as `the letter a, the
 622                          * character -, and the letter a'.
 623                          *
 624                          * For compatibility, the `-' is not considered
 625                          * to define a range if the character following
 626                          * it is either a close bracket (required by ANSI)
 627                          * or is not numerically greater than the character
 628                          * we just stored in the table (c).
 629                          */
 630                         n = *fmt;
 631                         if (n == ']' || n < c) {
 632                                 c = '-';
 633                                 break;  /* resume the for(;;) */
 634                         }
 635                         fmt++;
 636                         /* fill in the range */
 637                         do {
 638                             tab[++c] = v;
 639                         } while (c < n);
 640                         c = n;
 641                         /*
 642                          * Alas, the V7 Unix scanf also treats formats
 643                          * such as [a-c-e] as `the letters a through e'.
 644                          * This too is permitted by the standard....
 645                          */
 646                         goto doswitch;
 647                         break;
 648
 649                 case ']':               /* end of scanset */
 650                         return (fmt);
 651
 652                 default:                /* just another character */
 653                         c = n;
 654                         break;
 655                 }
 656         }
 657         /* NOTREACHED */
 658 }