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 __FBSDID("$FreeBSD$");
  41
  42 #include <sys/param.h>
  43 #include <sys/systm.h>
  44 #include <sys/ctype.h>
  45 #include <sys/limits.h>
  46 #include <sys/stddef.h>
  47
  48 /*
  49  * Note that stdarg.h and the ANSI style va_start macro is used for both
  50  * ANSI and traditional C compilers.
  51  */
  52 #include <machine/stdarg.h>
  53
  54 #define BUF             32      /* Maximum length of numeric string. */
  55
  56 /*
  57  * Flags used during conversion.
  58  */
  59 #define LONG            0x01    /* l: long or double */
  60 #define SHORT           0x04    /* h: short */
  61 #define SUPPRESS        0x08    /* suppress assignment */
  62 #define POINTER         0x10    /* weird %p pointer (`fake hex') */
  63 #define NOSKIP          0x20    /* do not skip blanks */
  64 #define QUAD            0x400
  65 #define INTMAXT         0x800   /* j: intmax_t */
  66 #define PTRDIFFT        0x1000  /* t: ptrdiff_t */
  67 #define SIZET           0x2000  /* z: size_t */
  68 #define SHORTSHORT      0x4000  /** hh: char */
  69
  70 /*
  71  * The following are used in numeric conversions only:
  72  * SIGNOK, NDIGITS, DPTOK, and EXPOK are for floating point;
  73  * SIGNOK, NDIGITS, PFXOK, and NZDIGITS are for integral.
  74  */
  75 #define SIGNOK          0x40    /* +/- is (still) legal */
  76 #define NDIGITS         0x80    /* no digits detected */
  77
  78 #define DPTOK           0x100   /* (float) decimal point is still legal */
  79 #define EXPOK           0x200   /* (float) exponent (e+3, etc) still legal */
  80
  81 #define PFXOK           0x100   /* 0x prefix is (still) legal */
  82 #define NZDIGITS        0x200   /* no zero digits detected */
  83
  84 /*
  85  * Conversion types.
  86  */
  87 #define CT_CHAR         0       /* %c conversion */
  88 #define CT_CCL          1       /* %[...] conversion */
  89 #define CT_STRING       2       /* %s conversion */
  90 #define CT_INT          3       /* integer, i.e., strtoq or strtouq */
  91 typedef u_quad_t (*ccfntype)(const char *, char **, int);
  92
  93 static const u_char *__sccl(char *, const u_char *);
  94
  95 int
  96 sscanf(const char *ibuf, const char *fmt, ...)
  97 {
  98         va_list ap;
  99         int ret;
 100
 101         va_start(ap, fmt);
 102         ret = vsscanf(ibuf, fmt, ap);
 103         va_end(ap);
 104         return(ret);
 105 }
 106
 107 int
 108 vsscanf(const char *inp, char const *fmt0, va_list ap)
 109 {
 110         int inr;
 111         const u_char *fmt = (const u_char *)fmt0;
 112         int c;                  /* character from format, or conversion */
 113         size_t width;           /* field width, or 0 */
 114         char *p;                /* points into all kinds of strings */
 115         int n;                  /* handy integer */
 116         int flags;              /* flags as defined above */
 117         char *p0;               /* saves original value of p when necessary */
 118         int nassigned;          /* number of fields assigned */
 119         int nconversions;       /* number of conversions */
 120         int nread;              /* number of characters consumed from fp */
 121         int base;               /* base argument to strtoq/strtouq */
 122         ccfntype ccfn;          /* conversion function (strtoq/strtouq) */
 123         char ccltab[256];       /* character class table for %[...] */
 124         char buf[BUF];          /* buffer for numeric conversions */
 125
 126         /* `basefix' is used to avoid `if' tests in the integer scanner */
 127         static short basefix[17] =
 128                 { 10, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 };
 129
 130         inr = strlen(inp);
 131
 132         nassigned = 0;
 133         nconversions = 0;
 134         nread = 0;
 135         base = 0;               /* XXX just to keep gcc happy */
 136         ccfn = NULL;            /* XXX just to keep gcc happy */
 137         for (;;) {
 138                 c = *fmt++;
 139                 if (c == 0)
 140                         return (nassigned);
 141                 if (isspace(c)) {
 142                         while (inr > 0 && isspace(*inp))
 143                                 nread++, inr--, inp++;
 144                         continue;
 145                 }
 146                 if (c != '%')
 147                         goto literal;
 148                 width = 0;
 149                 flags = 0;
 150                 /*
 151                  * switch on the format.  continue if done;
 152                  * break once format type is derived.
 153                  */
 154 again:          c = *fmt++;
 155                 switch (c) {
 156                 case '%':
 157 literal:
 158                         if (inr <= 0)
 159                                 goto input_failure;
 160                         if (*inp != c)
 161                                 goto match_failure;
 162                         inr--, inp++;
 163                         nread++;
 164                         continue;
 165
 166                 case '*':
 167                         flags |= SUPPRESS;
 168                         goto again;
 169                 case 'j':
 170                         flags |= INTMAXT;
 171                         goto again;
 172                 case 'l':
 173                         if (flags & LONG){
 174                                 flags &= ~LONG;
 175                                 flags |= QUAD;
 176                         } else {
 177                                 flags |= LONG;
 178                         }
 179                         goto again;
 180                 case 'q':
 181                         flags |= QUAD;
 182                         goto again;
 183                 case 't':
 184                         flags |= PTRDIFFT;
 185                         goto again;
 186                 case 'z':
 187                         flags |= SIZET;
 188                         goto again;
 189                 case 'h':
 190                         if (flags & SHORT){
 191                                 flags &= ~SHORT;
 192                                 flags |= SHORTSHORT;
 193                         } else {
 194                                 flags |= SHORT;
 195                         }
 196                         goto again;
 197
 198                 case '0': case '1': case '2': case '3': case '4':
 199                 case '5': case '6': case '7': case '8': case '9':
 200                         width = width * 10 + c - '0';
 201                         goto again;
 202
 203                 /*
 204                  * Conversions.
 205                  *
 206                  */
 207                 case 'd':
 208                         c = CT_INT;
 209                         ccfn = (ccfntype)strtoq;
 210                         base = 10;
 211                         break;
 212
 213                 case 'i':
 214                         c = CT_INT;
 215                         ccfn = (ccfntype)strtoq;
 216                         base = 0;
 217                         break;
 218
 219                 case 'o':
 220                         c = CT_INT;
 221                         ccfn = strtouq;
 222                         base = 8;
 223                         break;
 224
 225                 case 'u':
 226                         c = CT_INT;
 227                         ccfn = strtouq;
 228                         base = 10;
 229                         break;
 230
 231                 case 'x':
 232                         flags |= PFXOK; /* enable 0x prefixing */
 233                         c = CT_INT;
 234                         ccfn = strtouq;
 235                         base = 16;
 236                         break;
 237
 238                 case 's':
 239                         c = CT_STRING;
 240                         break;
 241
 242                 case '[':
 243                         fmt = __sccl(ccltab, fmt);
 244                         flags |= NOSKIP;
 245                         c = CT_CCL;
 246                         break;
 247
 248                 case 'c':
 249                         flags |= NOSKIP;
 250                         c = CT_CHAR;
 251                         break;
 252
 253                 case 'p':       /* pointer format is like hex */
 254                         flags |= POINTER | PFXOK;
 255                         c = CT_INT;
 256                         ccfn = strtouq;
 257                         base = 16;
 258                         break;
 259
 260                 case 'n':
 261                         nconversions++;
 262                         if (flags & SUPPRESS)   /* ??? */
 263                                 continue;
 264                         if (flags & SHORTSHORT)
 265                                 *va_arg(ap, char *) = nread;
 266                         else if (flags & SHORT)
 267                                 *va_arg(ap, short *) = nread;
 268                         else if (flags & LONG)
 269                                 *va_arg(ap, long *) = nread;
 270                         else if (flags & QUAD)
 271                                 *va_arg(ap, quad_t *) = nread;
 272                         else if (flags & INTMAXT)
 273                                 *va_arg(ap, intmax_t *) = nread;
 274                         else if (flags & SIZET)
 275                                 *va_arg(ap, size_t *) = nread;
 276                         else if (flags & PTRDIFFT)
 277                                 *va_arg(ap, ptrdiff_t *) = nread;
 278                         else
 279                                 *va_arg(ap, int *) = nread;
 280                         continue;
 281                 }
 282
 283                 /*
 284                  * We have a conversion that requires input.
 285                  */
 286                 if (inr <= 0)
 287                         goto input_failure;
 288
 289                 /*
 290                  * Consume leading white space, except for formats
 291                  * that suppress this.
 292                  */
 293                 if ((flags & NOSKIP) == 0) {
 294                         while (isspace(*inp)) {
 295                                 nread++;
 296                                 if (--inr > 0)
 297                                         inp++;
 298                                 else
 299                                         goto input_failure;
 300                         }
 301                         /*
 302                          * Note that there is at least one character in
 303                          * the buffer, so conversions that do not set NOSKIP
 304                          * can no longer result in an input failure.
 305                          */
 306                 }
 307
 308                 /*
 309                  * Do the conversion.
 310                  */
 311                 switch (c) {
 312
 313                 case CT_CHAR:
 314                         /* scan arbitrary characters (sets NOSKIP) */
 315                         if (width == 0)
 316                                 width = 1;
 317                         if (flags & SUPPRESS) {
 318                                 size_t sum = 0;
 319                                 for (;;) {
 320                                         if ((n = inr) < width) {
 321                                                 sum += n;
 322                                                 width -= n;
 323                                                 inp += n;
 324                                                 if (sum == 0)
 325                                                         goto input_failure;
 326                                                 break;
 327                                         } else {
 328                                                 sum += width;
 329                                                 inr -= width;
 330                                                 inp += width;
 331                                                 break;
 332                                         }
 333                                 }
 334                                 nread += sum;
 335                         } else {
 336                                 bcopy(inp, va_arg(ap, char *), width);
 337                                 inr -= width;
 338                                 inp += width;
 339                                 nread += width;
 340                                 nassigned++;
 341                         }
 342                         nconversions++;
 343                         break;
 344
 345                 case CT_CCL:
 346                         /* scan a (nonempty) character class (sets NOSKIP) */
 347                         if (width == 0)
 348                                 width = (size_t)~0;     /* `infinity' */
 349                         /* take only those things in the class */
 350                         if (flags & SUPPRESS) {
 351                                 n = 0;
 352                                 while (ccltab[(unsigned char)*inp]) {
 353                                         n++, inr--, inp++;
 354                                         if (--width == 0)
 355                                                 break;
 356                                         if (inr <= 0) {
 357                                                 if (n == 0)
 358                                                         goto input_failure;
 359                                                 break;
 360                                         }
 361                                 }
 362                                 if (n == 0)
 363                                         goto match_failure;
 364                         } else {
 365                                 p0 = p = va_arg(ap, char *);
 366                                 while (ccltab[(unsigned char)*inp]) {
 367                                         inr--;
 368                                         *p++ = *inp++;
 369                                         if (--width == 0)
 370                                                 break;
 371                                         if (inr <= 0) {
 372                                                 if (p == p0)
 373                                                         goto input_failure;
 374                                                 break;
 375                                         }
 376                                 }
 377                                 n = p - p0;
 378                                 if (n == 0)
 379                                         goto match_failure;
 380                                 *p = 0;
 381                                 nassigned++;
 382                         }
 383                         nread += n;
 384                         nconversions++;
 385                         break;
 386
 387                 case CT_STRING:
 388                         /* like CCL, but zero-length string OK, & no NOSKIP */
 389                         if (width == 0)
 390                                 width = (size_t)~0;
 391                         if (flags & SUPPRESS) {
 392                                 n = 0;
 393                                 while (!isspace(*inp)) {
 394                                         n++, inr--, inp++;
 395                                         if (--width == 0)
 396                                                 break;
 397                                         if (inr <= 0)
 398                                                 break;
 399                                 }
 400                                 nread += n;
 401                         } else {
 402                                 p0 = p = va_arg(ap, char *);
 403                                 while (!isspace(*inp)) {
 404                                         inr--;
 405                                         *p++ = *inp++;
 406                                         if (--width == 0)
 407                                                 break;
 408                                         if (inr <= 0)
 409                                                 break;
 410                                 }
 411                                 *p = 0;
 412                                 nread += p - p0;
 413                                 nassigned++;
 414                         }
 415                         nconversions++;
 416                         continue;
 417
 418                 case CT_INT:
 419                         /* scan an integer as if by strtoq/strtouq */
 420 #ifdef hardway
 421                         if (width == 0 || width > sizeof(buf) - 1)
 422                                 width = sizeof(buf) - 1;
 423 #else
 424                         /* size_t is unsigned, hence this optimisation */
 425                         if (--width > sizeof(buf) - 2)
 426                                 width = sizeof(buf) - 2;
 427                         width++;
 428 #endif
 429                         flags |= SIGNOK | NDIGITS | NZDIGITS;
 430                         for (p = buf; width; width--) {
 431                                 c = *inp;
 432                                 /*
 433                                  * Switch on the character; `goto ok'
 434                                  * if we accept it as a part of number.
 435                                  */
 436                                 switch (c) {
 437
 438                                 /*
 439                                  * The digit 0 is always legal, but is
 440                                  * special.  For %i conversions, if no
 441                                  * digits (zero or nonzero) have been
 442                                  * scanned (only signs), we will have
 443                                  * base==0.  In that case, we should set
 444                                  * it to 8 and enable 0x prefixing.
 445                                  * Also, if we have not scanned zero digits
 446                                  * before this, do not turn off prefixing
 447                                  * (someone else will turn it off if we
 448                                  * have scanned any nonzero digits).
 449                                  */
 450                                 case '0':
 451                                         if (base == 0) {
 452                                                 base = 8;
 453                                                 flags |= PFXOK;
 454                                         }
 455                                         if (flags & NZDIGITS)
 456                                             flags &= ~(SIGNOK|NZDIGITS|NDIGITS);
 457                                         else
 458                                             flags &= ~(SIGNOK|PFXOK|NDIGITS);
 459                                         goto ok;
 460
 461                                 /* 1 through 7 always legal */
 462                                 case '1': case '2': case '3':
 463                                 case '4': case '5': case '6': case '7':
 464                                         base = basefix[base];
 465                                         flags &= ~(SIGNOK | PFXOK | NDIGITS);
 466                                         goto ok;
 467
 468                                 /* digits 8 and 9 ok iff decimal or hex */
 469                                 case '8': case '9':
 470                                         base = basefix[base];
 471                                         if (base <= 8)
 472                                                 break;  /* not legal here */
 473                                         flags &= ~(SIGNOK | PFXOK | NDIGITS);
 474                                         goto ok;
 475
 476                                 /* letters ok iff hex */
 477                                 case 'A': case 'B': case 'C':
 478                                 case 'D': case 'E': case 'F':
 479                                 case 'a': case 'b': case 'c':
 480                                 case 'd': case 'e': case 'f':
 481                                         /* no need to fix base here */
 482                                         if (base <= 10)
 483                                                 break;  /* not legal here */
 484                                         flags &= ~(SIGNOK | PFXOK | NDIGITS);
 485                                         goto ok;
 486
 487                                 /* sign ok only as first character */
 488                                 case '+': case '-':
 489                                         if (flags & SIGNOK) {
 490                                                 flags &= ~SIGNOK;
 491                                                 goto ok;
 492                                         }
 493                                         break;
 494
 495                                 /* x ok iff flag still set & 2nd char */
 496                                 case 'x': case 'X':
 497                                         if (flags & PFXOK && p == buf + 1) {
 498                                                 base = 16;      /* if %i */
 499                                                 flags &= ~PFXOK;
 500                                                 goto ok;
 501                                         }
 502                                         break;
 503                                 }
 504
 505                                 /*
 506                                  * If we got here, c is not a legal character
 507                                  * for a number.  Stop accumulating digits.
 508                                  */
 509                                 break;
 510                 ok:
 511                                 /*
 512                                  * c is legal: store it and look at the next.
 513                                  */
 514                                 *p++ = c;
 515                                 if (--inr > 0)
 516                                         inp++;
 517                                 else
 518                                         break;          /* end of input */
 519                         }
 520                         /*
 521                          * If we had only a sign, it is no good; push
 522                          * back the sign.  If the number ends in `x',
 523                          * it was [sign] '0' 'x', so push back the x
 524                          * and treat it as [sign] '0'.
 525                          */
 526                         if (flags & NDIGITS) {
 527                                 if (p > buf) {
 528                                         inp--;
 529                                         inr++;
 530                                 }
 531                                 goto match_failure;
 532                         }
 533                         c = ((u_char *)p)[-1];
 534                         if (c == 'x' || c == 'X') {
 535                                 --p;
 536                                 inp--;
 537                                 inr++;
 538                         }
 539                         if ((flags & SUPPRESS) == 0) {
 540                                 u_quad_t res;
 541
 542                                 *p = 0;
 543                                 res = (*ccfn)(buf, (char **)NULL, base);
 544                                 if (flags & POINTER)
 545                                         *va_arg(ap, void **) =
 546                                                 (void *)(uintptr_t)res;
 547                                 else if (flags & SHORTSHORT)
 548                                         *va_arg(ap, char *) = res;
 549                                 else if (flags & SHORT)
 550                                         *va_arg(ap, short *) = res;
 551                                 else if (flags & LONG)
 552                                         *va_arg(ap, long *) = res;
 553                                 else if (flags & QUAD)
 554                                         *va_arg(ap, quad_t *) = res;
 555                                 else if (flags & INTMAXT)
 556                                         *va_arg(ap, intmax_t *) = res;
 557                                 else if (flags & PTRDIFFT)
 558                                         *va_arg(ap, ptrdiff_t *) = res;
 559                                 else if (flags & SIZET)
 560                                         *va_arg(ap, size_t *) = res;
 561                                 else
 562                                         *va_arg(ap, int *) = res;
 563                                 nassigned++;
 564                         }
 565                         nread += p - buf;
 566                         nconversions++;
 567                         break;
 568
 569                 }
 570         }
 571 input_failure:
 572         return (nconversions != 0 ? nassigned : -1);
 573 match_failure:
 574         return (nassigned);
 575 }
 576
 577 /*
 578  * Fill in the given table from the scanset at the given format
 579  * (just after `[').  Return a pointer to the character past the
 580  * closing `]'.  The table has a 1 wherever characters should be
 581  * considered part of the scanset.
 582  */
 583 static const u_char *
 584 __sccl(char *tab, const u_char *fmt)
 585 {
 586         int c, n, v;
 587
 588         /* first `clear' the whole table */
 589         c = *fmt++;             /* first char hat => negated scanset */
 590         if (c == '^') {
 591                 v = 1;          /* default => accept */
 592                 c = *fmt++;     /* get new first char */
 593         } else
 594                 v = 0;          /* default => reject */
 595
 596         /* XXX: Will not work if sizeof(tab*) > sizeof(char) */
 597         for (n = 0; n < 256; n++)
 598                      tab[n] = v;        /* memset(tab, v, 256) */
 599
 600         if (c == 0)
 601                 return (fmt - 1);/* format ended before closing ] */
 602
 603         /*
 604          * Now set the entries corresponding to the actual scanset
 605          * to the opposite of the above.
 606          *
 607          * The first character may be ']' (or '-') without being special;
 608          * the last character may be '-'.
 609          */
 610         v = 1 - v;
 611         for (;;) {
 612                 tab[c] = v;             /* take character c */
 613 doswitch:
 614                 n = *fmt++;             /* and examine the next */
 615                 switch (n) {
 616
 617                 case 0:                 /* format ended too soon */
 618                         return (fmt - 1);
 619
 620                 case '-':
 621                         /*
 622                          * A scanset of the form
 623                          *      [01+-]
 624                          * is defined as `the digit 0, the digit 1,
 625                          * the character +, the character -', but
 626                          * the effect of a scanset such as
 627                          *      [a-zA-Z0-9]
 628                          * is implementation defined.  The V7 Unix
 629                          * scanf treats `a-z' as `the letters a through
 630                          * z', but treats `a-a' as `the letter a, the
 631                          * character -, and the letter a'.
 632                          *
 633                          * For compatibility, the `-' is not considered
 634                          * to define a range if the character following
 635                          * it is either a close bracket (required by ANSI)
 636                          * or is not numerically greater than the character
 637                          * we just stored in the table (c).
 638                          */
 639                         n = *fmt;
 640                         if (n == ']' || n < c) {
 641                                 c = '-';
 642                                 break;  /* resume the for(;;) */
 643                         }
 644                         fmt++;
 645                         /* fill in the range */
 646                         do {
 647                             tab[++c] = v;
 648                         } while (c < n);
 649                         c = n;
 650                         /*
 651                          * Alas, the V7 Unix scanf also treats formats
 652                          * such as [a-c-e] as `the letters a through e'.
 653                          * This too is permitted by the standard....
 654                          */
 655                         goto doswitch;
 656                         break;
 657
 658                 case ']':               /* end of scanset */
 659                         return (fmt);
 660
 661                 default:                /* just another character */
 662                         c = n;
 663                         break;
 664                 }
 665         }
 666         /* NOTREACHED */
 667 }
 668