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  * 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/cdefs.h>
  40 #include <sys/param.h>
  41 #include <sys/systm.h>
  42 #include <sys/ctype.h>
  43 #include <sys/limits.h>
  44 #include <sys/stddef.h>
  45
  46 /*
  47  * Note that stdarg.h and the ANSI style va_start macro is used for both
  48  * ANSI and traditional C compilers.
  49  */
  50 #include <machine/stdarg.h>
  51
  52 #define BUF             32      /* Maximum length of numeric string. */
  53
  54 /*
  55  * Flags used during conversion.
  56  */
  57 #define LONG            0x01    /* l: long or double */
  58 #define SHORT           0x04    /* h: short */
  59 #define SUPPRESS        0x08    /* suppress assignment */
  60 #define POINTER         0x10    /* weird %p pointer (`fake hex') */
  61 #define NOSKIP          0x20    /* do not skip blanks */
  62 #define QUAD            0x400
  63 #define INTMAXT         0x800   /* j: intmax_t */
  64 #define PTRDIFFT        0x1000  /* t: ptrdiff_t */
  65 #define SIZET           0x2000  /* z: size_t */
  66 #define SHORTSHORT      0x4000  /** hh: char */
  67
  68 /*
  69  * The following are used in numeric conversions only:
  70  * SIGNOK, NDIGITS, DPTOK, and EXPOK are for floating point;
  71  * SIGNOK, NDIGITS, PFXOK, and NZDIGITS are for integral.
  72  */
  73 #define SIGNOK          0x40    /* +/- is (still) legal */
  74 #define NDIGITS         0x80    /* no digits detected */
  75
  76 #define DPTOK           0x100   /* (float) decimal point is still legal */
  77 #define EXPOK           0x200   /* (float) exponent (e+3, etc) still legal */
  78
  79 #define PFXOK           0x100   /* 0x prefix is (still) legal */
  80 #define NZDIGITS        0x200   /* no zero digits detected */
  81
  82 /*
  83  * Conversion types.
  84  */
  85 #define CT_CHAR         0       /* %c conversion */
  86 #define CT_CCL          1       /* %[...] conversion */
  87 #define CT_STRING       2       /* %s conversion */
  88 #define CT_INT          3       /* integer, i.e., strtoq or strtouq */
  89 typedef u_quad_t (*ccfntype)(const char *, char **, int);
  90
  91 static const u_char *__sccl(char *, const u_char *);
  92
  93 int
  94 sscanf(const char *ibuf, const char *fmt, ...)
  95 {
  96         va_list ap;
  97         int ret;
  98
  99         va_start(ap, fmt);
 100         ret = vsscanf(ibuf, fmt, ap);
 101         va_end(ap);
 102         return(ret);
 103 }
 104
 105 int
 106 vsscanf(const char *inp, char const *fmt0, va_list ap)
 107 {
 108         int inr;
 109         const u_char *fmt = (const u_char *)fmt0;
 110         int c;                  /* character from format, or conversion */
 111         size_t width;           /* field width, or 0 */
 112         char *p;                /* points into all kinds of strings */
 113         int n;                  /* handy integer */
 114         int flags;              /* flags as defined above */
 115         char *p0;               /* saves original value of p when necessary */
 116         int nassigned;          /* number of fields assigned */
 117         int nconversions;       /* number of conversions */
 118         int nread;              /* number of characters consumed from fp */
 119         int base;               /* base argument to strtoq/strtouq */
 120         ccfntype ccfn;          /* conversion function (strtoq/strtouq) */
 121         char ccltab[256];       /* character class table for %[...] */
 122         char buf[BUF];          /* buffer for numeric conversions */
 123
 124         /* `basefix' is used to avoid `if' tests in the integer scanner */
 125         static short basefix[17] =
 126                 { 10, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 };
 127
 128         inr = strlen(inp);
 129
 130         nassigned = 0;
 131         nconversions = 0;
 132         nread = 0;
 133         base = 0;               /* XXX just to keep gcc happy */
 134         ccfn = NULL;            /* XXX just to keep gcc happy */
 135         for (;;) {
 136                 c = *fmt++;
 137                 if (c == 0)
 138                         return (nassigned);
 139                 if (isspace(c)) {
 140                         while (inr > 0 && isspace(*inp))
 141                                 nread++, inr--, inp++;
 142                         continue;
 143                 }
 144                 if (c != '%')
 145                         goto literal;
 146                 width = 0;
 147                 flags = 0;
 148                 /*
 149                  * switch on the format.  continue if done;
 150                  * break once format type is derived.
 151                  */
 152 again:          c = *fmt++;
 153                 switch (c) {
 154                 case '%':
 155 literal:
 156                         if (inr <= 0)
 157                                 goto input_failure;
 158                         if (*inp != c)
 159                                 goto match_failure;
 160                         inr--, inp++;
 161                         nread++;
 162                         continue;
 163
 164                 case '*':
 165                         flags |= SUPPRESS;
 166                         goto again;
 167                 case 'j':
 168                         flags |= INTMAXT;
 169                         goto again;
 170                 case 'l':
 171                         if (flags & LONG){
 172                                 flags &= ~LONG;
 173                                 flags |= QUAD;
 174                         } else {
 175                                 flags |= LONG;
 176                         }
 177                         goto again;
 178                 case 'q':
 179                         flags |= QUAD;
 180                         goto again;
 181                 case 't':
 182                         flags |= PTRDIFFT;
 183                         goto again;
 184                 case 'z':
 185                         flags |= SIZET;
 186                         goto again;
 187                 case 'h':
 188                         if (flags & SHORT){
 189                                 flags &= ~SHORT;
 190                                 flags |= SHORTSHORT;
 191                         } else {
 192                                 flags |= SHORT;
 193                         }
 194                         goto again;
 195
 196                 case '0': case '1': case '2': case '3': case '4':
 197                 case '5': case '6': case '7': case '8': case '9':
 198                         width = width * 10 + c - '0';
 199                         goto again;
 200
 201                 /*
 202                  * Conversions.
 203                  *
 204                  */
 205                 case 'd':
 206                         c = CT_INT;
 207                         ccfn = (ccfntype)strtoq;
 208                         base = 10;
 209                         break;
 210
 211                 case 'i':
 212                         c = CT_INT;
 213                         ccfn = (ccfntype)strtoq;
 214                         base = 0;
 215                         break;
 216
 217                 case 'o':
 218                         c = CT_INT;
 219                         ccfn = strtouq;
 220                         base = 8;
 221                         break;
 222
 223                 case 'u':
 224                         c = CT_INT;
 225                         ccfn = strtouq;
 226                         base = 10;
 227                         break;
 228
 229                 case 'x':
 230                         flags |= PFXOK; /* enable 0x prefixing */
 231                         c = CT_INT;
 232                         ccfn = strtouq;
 233                         base = 16;
 234                         break;
 235
 236                 case 's':
 237                         c = CT_STRING;
 238                         break;
 239
 240                 case '[':
 241                         fmt = __sccl(ccltab, fmt);
 242                         flags |= NOSKIP;
 243                         c = CT_CCL;
 244                         break;
 245
 246                 case 'c':
 247                         flags |= NOSKIP;
 248                         c = CT_CHAR;
 249                         break;
 250
 251                 case 'p':       /* pointer format is like hex */
 252                         flags |= POINTER | PFXOK;
 253                         c = CT_INT;
 254                         ccfn = strtouq;
 255                         base = 16;
 256                         break;
 257
 258                 case 'n':
 259                         nconversions++;
 260                         if (flags & SUPPRESS)   /* ??? */
 261                                 continue;
 262                         if (flags & SHORTSHORT)
 263                                 *va_arg(ap, char *) = nread;
 264                         else if (flags & SHORT)
 265                                 *va_arg(ap, short *) = nread;
 266                         else if (flags & LONG)
 267                                 *va_arg(ap, long *) = nread;
 268                         else if (flags & QUAD)
 269                                 *va_arg(ap, quad_t *) = nread;
 270                         else if (flags & INTMAXT)
 271                                 *va_arg(ap, intmax_t *) = nread;
 272                         else if (flags & SIZET)
 273                                 *va_arg(ap, size_t *) = nread;
 274                         else if (flags & PTRDIFFT)
 275                                 *va_arg(ap, ptrdiff_t *) = nread;
 276                         else
 277                                 *va_arg(ap, int *) = nread;
 278                         continue;
 279                 }
 280
 281                 /*
 282                  * We have a conversion that requires input.
 283                  */
 284                 if (inr <= 0)
 285                         goto input_failure;
 286
 287                 /*
 288                  * Consume leading white space, except for formats
 289                  * that suppress this.
 290                  */
 291                 if ((flags & NOSKIP) == 0) {
 292                         while (isspace(*inp)) {
 293                                 nread++;
 294                                 if (--inr > 0)
 295                                         inp++;
 296                                 else
 297                                         goto input_failure;
 298                         }
 299                         /*
 300                          * Note that there is at least one character in
 301                          * the buffer, so conversions that do not set NOSKIP
 302                          * can no longer result in an input failure.
 303                          */
 304                 }
 305
 306                 /*
 307                  * Do the conversion.
 308                  */
 309                 switch (c) {
 310                 case CT_CHAR:
 311                         /* scan arbitrary characters (sets NOSKIP) */
 312                         if (width == 0)
 313                                 width = 1;
 314                         if (flags & SUPPRESS) {
 315                                 size_t sum = 0;
 316                                 for (;;) {
 317                                         if ((n = inr) < width) {
 318                                                 sum += n;
 319                                                 width -= n;
 320                                                 inp += n;
 321                                                 if (sum == 0)
 322                                                         goto input_failure;
 323                                                 break;
 324                                         } else {
 325                                                 sum += width;
 326                                                 inr -= width;
 327                                                 inp += width;
 328                                                 break;
 329                                         }
 330                                 }
 331                                 nread += sum;
 332                         } else {
 333                                 bcopy(inp, va_arg(ap, char *), width);
 334                                 inr -= width;
 335                                 inp += width;
 336                                 nread += width;
 337                                 nassigned++;
 338                         }
 339                         nconversions++;
 340                         break;
 341
 342                 case CT_CCL:
 343                         /* scan a (nonempty) character class (sets NOSKIP) */
 344                         if (width == 0)
 345                                 width = (size_t)~0;     /* `infinity' */
 346                         /* take only those things in the class */
 347                         if (flags & SUPPRESS) {
 348                                 n = 0;
 349                                 while (ccltab[(unsigned char)*inp]) {
 350                                         n++, inr--, inp++;
 351                                         if (--width == 0)
 352                                                 break;
 353                                         if (inr <= 0) {
 354                                                 if (n == 0)
 355                                                         goto input_failure;
 356                                                 break;
 357                                         }
 358                                 }
 359                                 if (n == 0)
 360                                         goto match_failure;
 361                         } else {
 362                                 p0 = p = va_arg(ap, char *);
 363                                 while (ccltab[(unsigned char)*inp]) {
 364                                         inr--;
 365                                         *p++ = *inp++;
 366                                         if (--width == 0)
 367                                                 break;
 368                                         if (inr <= 0) {
 369                                                 if (p == p0)
 370                                                         goto input_failure;
 371                                                 break;
 372                                         }
 373                                 }
 374                                 n = p - p0;
 375                                 if (n == 0)
 376                                         goto match_failure;
 377                                 *p = 0;
 378                                 nassigned++;
 379                         }
 380                         nread += n;
 381                         nconversions++;
 382                         break;
 383
 384                 case CT_STRING:
 385                         /* like CCL, but zero-length string OK, & no NOSKIP */
 386                         if (width == 0)
 387                                 width = (size_t)~0;
 388                         if (flags & SUPPRESS) {
 389                                 n = 0;
 390                                 while (!isspace(*inp)) {
 391                                         n++, inr--, inp++;
 392                                         if (--width == 0)
 393                                                 break;
 394                                         if (inr <= 0)
 395                                                 break;
 396                                 }
 397                                 nread += n;
 398                         } else {
 399                                 p0 = p = va_arg(ap, char *);
 400                                 while (!isspace(*inp)) {
 401                                         inr--;
 402                                         *p++ = *inp++;
 403                                         if (--width == 0)
 404                                                 break;
 405                                         if (inr <= 0)
 406                                                 break;
 407                                 }
 408                                 *p = 0;
 409                                 nread += p - p0;
 410                                 nassigned++;
 411                         }
 412                         nconversions++;
 413                         continue;
 414
 415                 case CT_INT:
 416                         /* scan an integer as if by strtoq/strtouq */
 417 #ifdef hardway
 418                         if (width == 0 || width > sizeof(buf) - 1)
 419                                 width = sizeof(buf) - 1;
 420 #else
 421                         /* size_t is unsigned, hence this optimisation */
 422                         if (--width > sizeof(buf) - 2)
 423                                 width = sizeof(buf) - 2;
 424                         width++;
 425 #endif
 426                         flags |= SIGNOK | NDIGITS | NZDIGITS;
 427                         for (p = buf; width; width--) {
 428                                 c = *inp;
 429                                 /*
 430                                  * Switch on the character; `goto ok'
 431                                  * if we accept it as a part of number.
 432                                  */
 433                                 switch (c) {
 434                                 /*
 435                                  * The digit 0 is always legal, but is
 436                                  * special.  For %i conversions, if no
 437                                  * digits (zero or nonzero) have been
 438                                  * scanned (only signs), we will have
 439                                  * base==0.  In that case, we should set
 440                                  * it to 8 and enable 0x prefixing.
 441                                  * Also, if we have not scanned zero digits
 442                                  * before this, do not turn off prefixing
 443                                  * (someone else will turn it off if we
 444                                  * have scanned any nonzero digits).
 445                                  */
 446                                 case '0':
 447                                         if (base == 0) {
 448                                                 base = 8;
 449                                                 flags |= PFXOK;
 450                                         }
 451                                         if (flags & NZDIGITS)
 452                                             flags &= ~(SIGNOK|NZDIGITS|NDIGITS);
 453                                         else
 454                                             flags &= ~(SIGNOK|PFXOK|NDIGITS);
 455                                         goto ok;
 456
 457                                 /* 1 through 7 always legal */
 458                                 case '1': case '2': case '3':
 459                                 case '4': case '5': case '6': case '7':
 460                                         base = basefix[base];
 461                                         flags &= ~(SIGNOK | PFXOK | NDIGITS);
 462                                         goto ok;
 463
 464                                 /* digits 8 and 9 ok iff decimal or hex */
 465                                 case '8': case '9':
 466                                         base = basefix[base];
 467                                         if (base <= 8)
 468                                                 break;  /* not legal here */
 469                                         flags &= ~(SIGNOK | PFXOK | NDIGITS);
 470                                         goto ok;
 471
 472                                 /* letters ok iff hex */
 473                                 case 'A': case 'B': case 'C':
 474                                 case 'D': case 'E': case 'F':
 475                                 case 'a': case 'b': case 'c':
 476                                 case 'd': case 'e': case 'f':
 477                                         /* no need to fix base here */
 478                                         if (base <= 10)
 479                                                 break;  /* not legal here */
 480                                         flags &= ~(SIGNOK | PFXOK | NDIGITS);
 481                                         goto ok;
 482
 483                                 /* sign ok only as first character */
 484                                 case '+': case '-':
 485                                         if (flags & SIGNOK) {
 486                                                 flags &= ~SIGNOK;
 487                                                 goto ok;
 488                                         }
 489                                         break;
 490
 491                                 /* x ok iff flag still set & 2nd char */
 492                                 case 'x': case 'X':
 493                                         if (flags & PFXOK && p == buf + 1) {
 494                                                 base = 16;      /* if %i */
 495                                                 flags &= ~PFXOK;
 496                                                 goto ok;
 497                                         }
 498                                         break;
 499                                 }
 500
 501                                 /*
 502                                  * If we got here, c is not a legal character
 503                                  * for a number.  Stop accumulating digits.
 504                                  */
 505                                 break;
 506                 ok:
 507                                 /*
 508                                  * c is legal: store it and look at the next.
 509                                  */
 510                                 *p++ = c;
 511                                 if (--inr > 0)
 512                                         inp++;
 513                                 else
 514                                         break;          /* end of input */
 515                         }
 516                         /*
 517                          * If we had only a sign, it is no good; push
 518                          * back the sign.  If the number ends in `x',
 519                          * it was [sign] '0' 'x', so push back the x
 520                          * and treat it as [sign] '0'.
 521                          */
 522                         if (flags & NDIGITS) {
 523                                 if (p > buf) {
 524                                         inp--;
 525                                         inr++;
 526                                 }
 527                                 goto match_failure;
 528                         }
 529                         c = ((u_char *)p)[-1];
 530                         if (c == 'x' || c == 'X') {
 531                                 --p;
 532                                 inp--;
 533                                 inr++;
 534                         }
 535                         if ((flags & SUPPRESS) == 0) {
 536                                 u_quad_t res;
 537
 538                                 *p = 0;
 539                                 res = (*ccfn)(buf, (char **)NULL, base);
 540                                 if (flags & POINTER)
 541                                         *va_arg(ap, void **) =
 542                                                 (void *)(uintptr_t)res;
 543                                 else if (flags & SHORTSHORT)
 544                                         *va_arg(ap, char *) = res;
 545                                 else if (flags & SHORT)
 546                                         *va_arg(ap, short *) = res;
 547                                 else if (flags & LONG)
 548                                         *va_arg(ap, long *) = res;
 549                                 else if (flags & QUAD)
 550                                         *va_arg(ap, quad_t *) = res;
 551                                 else if (flags & INTMAXT)
 552                                         *va_arg(ap, intmax_t *) = res;
 553                                 else if (flags & PTRDIFFT)
 554                                         *va_arg(ap, ptrdiff_t *) = res;
 555                                 else if (flags & SIZET)
 556                                         *va_arg(ap, size_t *) = res;
 557                                 else
 558                                         *va_arg(ap, int *) = res;
 559                                 nassigned++;
 560                         }
 561                         nread += p - buf;
 562                         nconversions++;
 563                         break;
 564                 }
 565         }
 566 input_failure:
 567         return (nconversions != 0 ? nassigned : -1);
 568 match_failure:
 569         return (nassigned);
 570 }
 571
 572 /*
 573  * Fill in the given table from the scanset at the given format
 574  * (just after `[').  Return a pointer to the character past the
 575  * closing `]'.  The table has a 1 wherever characters should be
 576  * considered part of the scanset.
 577  */
 578 static const u_char *
 579 __sccl(char *tab, const u_char *fmt)
 580 {
 581         int c, n, v;
 582
 583         /* first `clear' the whole table */
 584         c = *fmt++;             /* first char hat => negated scanset */
 585         if (c == '^') {
 586                 v = 1;          /* default => accept */
 587                 c = *fmt++;     /* get new first char */
 588         } else
 589                 v = 0;          /* default => reject */
 590
 591         /* XXX: Will not work if sizeof(tab*) > sizeof(char) */
 592         for (n = 0; n < 256; n++)
 593                      tab[n] = v;        /* memset(tab, v, 256) */
 594
 595         if (c == 0)
 596                 return (fmt - 1);/* format ended before closing ] */
 597
 598         /*
 599          * Now set the entries corresponding to the actual scanset
 600          * to the opposite of the above.
 601          *
 602          * The first character may be ']' (or '-') without being special;
 603          * the last character may be '-'.
 604          */
 605         v = 1 - v;
 606         for (;;) {
 607                 tab[c] = v;             /* take character c */
 608 doswitch:
 609                 n = *fmt++;             /* and examine the next */
 610                 switch (n) {
 611                 case 0:                 /* format ended too soon */
 612                         return (fmt - 1);
 613
 614                 case '-':
 615                         /*
 616                          * A scanset of the form
 617                          *      [01+-]
 618                          * is defined as `the digit 0, the digit 1,
 619                          * the character +, the character -', but
 620                          * the effect of a scanset such as
 621                          *      [a-zA-Z0-9]
 622                          * is implementation defined.  The V7 Unix
 623                          * scanf treats `a-z' as `the letters a through
 624                          * z', but treats `a-a' as `the letter a, the
 625                          * character -, and the letter a'.
 626                          *
 627                          * For compatibility, the `-' is not considered
 628                          * to define a range if the character following
 629                          * it is either a close bracket (required by ANSI)
 630                          * or is not numerically greater than the character
 631                          * we just stored in the table (c).
 632                          */
 633                         n = *fmt;
 634                         if (n == ']' || n < c) {
 635                                 c = '-';
 636                                 break;  /* resume the for(;;) */
 637                         }
 638                         fmt++;
 639                         /* fill in the range */
 640                         do {
 641                             tab[++c] = v;
 642                         } while (c < n);
 643                         c = n;
 644                         /*
 645                          * Alas, the V7 Unix scanf also treats formats
 646                          * such as [a-c-e] as `the letters a through e'.
 647                          * This too is permitted by the standard....
 648                          */
 649                         goto doswitch;
 650                         break;
 651
 652                 case ']':               /* end of scanset */
 653                         return (fmt);
 654
 655                 default:                /* just another character */
 656                         c = n;
 657                         break;
 658                 }
 659         }
 660         /* NOTREACHED */
 661 }