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