lib/sscanf.c

   1 // SPDX-License-Identifier: BSD-3-Clause
   2 /*
   3  * Copyright (c) 1990, 1993
   4  * The Regents of the University of California. All rights reserved.
   5  *
   6  * This code is derived from software contributed to Berkeley by
   7  * Chris Torek.
   8  *
   9  * Copyright (c) 2011 The FreeBSD Foundation
  10  * All rights reserved.
  11  * Portions of this software were developed by David Chisnall
  12  * under sponsorship from the FreeBSD Foundation.
  13  *
  14  * Author: Juergen Gross <[email protected]>
  15  * Date: Jun 2016
  16  */
  17
  18 #if !defined HAVE_LIBC
  19
  20 #include <os.h>
  21 #include <linux/kernel.h>
  22 #include <linux/ctype.h>
  23 #include <vsprintf.h>
  24 #include <linux/string.h>
  25 #include <malloc.h>
  26 #define __DECONST(type, var)    ((type)(uintptr_t)(const void *)(var))
  27
  28 /**
  29  * struct str_info - Input string parameters
  30  * @neg: negative number or not
  31  *       0 - not negative
  32  *       1 - negative
  33  * @any: set any if any `digits' consumed; make it negative to indicate
  34  *       overflow
  35  * @acc: accumulated value
  36  */
  37 struct str_info {
  38         int neg, any;
  39         u64 acc;
  40 };
  41
  42 /**
  43  * str_to_int_convert() - Write string data to structure
  44  * @nptr: pointer to string
  45  * @base: number's base
  46  * @unsign: describes what integer is expected
  47  *          0 - not unsigned
  48  *          1 - unsigned
  49  *
  50  * Ignores `locale' stuff.  Assumes that the upper and lower case
  51  * alphabets and digits are each contiguous.
  52  *
  53  * Return: struct str_info *, which contains string data to future process
  54  */
  55 static struct str_info *
  56 str_to_int_convert(const char **nptr, int base, unsigned int unsign)
  57 {
  58         const char *s = *nptr;
  59         u64 acc;
  60         unsigned char c;
  61         u64 cutoff;
  62         int neg, any, cutlim;
  63         u64 qbase;
  64         struct str_info *info;
  65
  66         /*
  67          * Skip white space and pick up leading +/- sign if any.
  68          * If base is 0, allow 0x for hex and 0 for octal, else
  69          * assume decimal; if base is already 16, allow 0x.
  70          */
  71         info = (struct str_info *)malloc(sizeof(struct str_info));
  72         if (!info)
  73                 return NULL;
  74
  75         do {
  76                 c = *s++;
  77         } while (isspace(c));
  78         if (c == '-') {
  79                 neg = 1;
  80                 c = *s++;
  81         } else {
  82                 neg = 0;
  83                 if (c == '+')
  84                         c = *s++;
  85         }
  86         if ((base == 0 || base == 16) &&
  87             c == '0' && (*s == 'x' || *s == 'X')) {
  88                 c = s[1];
  89                 s += 2;
  90                 base = 16;
  91         }
  92         if (base == 0)
  93                 base = c == '0' ? 8 : 10;
  94
  95         /*
  96          * Compute the cutoff value between legal numbers and illegal
  97          * numbers.  That is the largest legal value, divided by the
  98          * base.  An input number that is greater than this value, if
  99          * followed by a legal input character, is too big.  One that
 100          * is equal to this value may be valid or not; the limit
 101          * between valid and invalid numbers is then based on the last
 102          * digit.  For instance, if the range for quads is
 103          * [-9223372036854775808..9223372036854775807] and the input base
 104          * is 10, cutoff will be set to 922337203685477580 and cutlim to
 105          * either 7 (neg==0) or 8 (neg==1), meaning that if we have
 106          * accumulated a value > 922337203685477580, or equal but the
 107          * next digit is > 7 (or 8), the number is too big, and we will
 108          * return a range error.
 109          *
 110          * Set any if any `digits' consumed; make it negative to indicate
 111          * overflow.
 112          */
 113         qbase = (unsigned int)base;
 114
 115         if (!unsign) {
 116                 cutoff = neg ? (u64)-(LLONG_MIN + LLONG_MAX) + LLONG_MAX : LLONG_MAX;
 117                 cutlim = cutoff % qbase;
 118                 cutoff /= qbase;
 119         } else {
 120                 cutoff = (u64)ULLONG_MAX / qbase;
 121                 cutlim = (u64)ULLONG_MAX % qbase;
 122         }
 123
 124         for (acc = 0, any = 0;; c = *s++) {
 125                 if (!isascii(c))
 126                         break;
 127                 if (isdigit(c))
 128                         c -= '0';
 129                 else if (isalpha(c))
 130                         c -= isupper(c) ? 'A' - 10 : 'a' - 10;
 131                 else
 132                         break;
 133                 if (c >= base)
 134                         break;
 135                 if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim)) {
 136                         any = -1;
 137                 } else {
 138                         any = 1;
 139                         acc *= qbase;
 140                         acc += c;
 141                 }
 142         }
 143
 144         info->any = any;
 145         info->neg = neg;
 146         info->acc = acc;
 147
 148         *nptr = s;
 149
 150         return info;
 151 }
 152
 153 /**
 154  * strtoq() - Convert a string to a quad integer
 155  * @nptr: pointer to string
 156  * @endptr: pointer to number's end in the string
 157  * @base: number's base
 158  *
 159  * Return: s64 quad integer number converted from input string
 160  */
 161 static s64
 162 strtoq(const char *nptr, char **endptr, int base)
 163 {
 164         const char *s = nptr;
 165         u64 acc;
 166         int unsign = 0;
 167         struct str_info *info;
 168
 169         info = str_to_int_convert(&s, base, unsign);
 170         if (!info)
 171                 return -1;
 172
 173         acc = info->acc;
 174
 175         if (info->any < 0)
 176                 acc = info->neg ? LLONG_MIN : LLONG_MAX;
 177         else if (info->neg)
 178                 acc = -acc;
 179         if (endptr != 0)
 180                 *endptr = __DECONST(char *, info->any ? s - 1 : nptr);
 181
 182         free(info);
 183
 184         return acc;
 185 }
 186
 187 /**
 188  * strtouq() - Convert a string to an unsigned quad integer
 189  * @nptr: pointer to string
 190  * @endptr: pointer to number's end in the string
 191  * @base: number's base
 192  *
 193  * Return: s64 unsigned quad integer number converted from
 194  *         input string
 195  */
 196 u64
 197 strtouq(const char *nptr, char **endptr, int base)
 198 {
 199                 const char *s = nptr;
 200         u64 acc;
 201         int unsign = 1;
 202         struct str_info *info;
 203
 204         info = str_to_int_convert(&s, base, unsign);
 205         if (!info)
 206                 return -1;
 207
 208         acc = info->acc;
 209
 210         if (info->any < 0)
 211                 acc = ULLONG_MAX;
 212         else if (info->neg)
 213                 acc = -acc;
 214         if (endptr != 0)
 215                 *endptr = __DECONST(char *, info->any ? s - 1 : nptr);
 216
 217         free(info);
 218
 219         return acc;
 220 }
 221
 222 /**
 223  * __sccl() - Fill in the given table from the scanset at the given format
 224  * (just after `[')
 225  * @tab: table to fill in
 226  * @fmt: format of buffer
 227  *
 228  * The table has a 1 wherever characters should be considered part of the
 229  * scanset.
 230  *
 231  * Return: pointer to the character past the closing `]'
 232  */
 233 static const u_char *
 234 __sccl(char *tab, const u_char *fmt)
 235 {
 236         int c, n, v;
 237
 238         /* first `clear' the whole table */
 239         c = *fmt++;             /* first char hat => negated scanset */
 240         if (c == '^') {
 241                 v = 1;          /* default => accept */
 242                 c = *fmt++;     /* get new first char */
 243         } else {
 244                 v = 0;          /* default => reject */
 245         }
 246
 247         /* XXX: Will not work if sizeof(tab*) > sizeof(char) */
 248         for (n = 0; n < 256; n++)
 249                 tab[n] = v;        /* memset(tab, v, 256) */
 250
 251         if (c == 0)
 252                 return (fmt - 1);/* format ended before closing ] */
 253
 254         /*
 255          * Now set the entries corresponding to the actual scanset
 256          * to the opposite of the above.
 257          *
 258          * The first character may be ']' (or '-') without being special;
 259          * the last character may be '-'.
 260          */
 261         v = 1 - v;
 262         for (;;) {
 263                 tab[c] = v;             /* take character c */
 264 doswitch:
 265                 n = *fmt++;             /* and examine the next */
 266                 switch (n) {
 267                 case 0:                 /* format ended too soon */
 268                         return (fmt - 1);
 269
 270                 case '-':
 271                         /*
 272                          * A scanset of the form
 273                          *      [01+-]
 274                          * is defined as `the digit 0, the digit 1,
 275                          * the character +, the character -', but
 276                          * the effect of a scanset such as
 277                          *      [a-zA-Z0-9]
 278                          * is implementation defined.  The V7 Unix
 279                          * scanf treats `a-z' as `the letters a through
 280                          * z', but treats `a-a' as `the letter a, the
 281                          * character -, and the letter a'.
 282                          *
 283                          * For compatibility, the `-' is not considerd
 284                          * to define a range if the character following
 285                          * it is either a close bracket (required by ANSI)
 286                          * or is not numerically greater than the character
 287                          * we just stored in the table (c).
 288                          */
 289                         n = *fmt;
 290                         if (n == ']' || n < c) {
 291                                 c = '-';
 292                                 break;  /* resume the for(;;) */
 293                         }
 294                         fmt++;
 295                         /* fill in the range */
 296                         do {
 297                                 tab[++c] = v;
 298                         } while (c < n);
 299                         c = n;
 300                         /*
 301                          * Alas, the V7 Unix scanf also treats formats
 302                          * such as [a-c-e] as `the letters a through e'.
 303                          * This too is permitted by the standard....
 304                          */
 305                         goto doswitch;
 306                         break;
 307
 308                 case ']':               /* end of scanset */
 309                         return (fmt);
 310
 311                 default:                /* just another character */
 312                         c = n;
 313                         break;
 314                 }
 315         }
 316         /* NOTREACHED */
 317 }
 318
 319 /**
 320  * vsscanf - Unformat a buffer into a list of arguments
 321  * @buf:        input buffer
 322  * @fmt:        format of buffer
 323  * @args:       arguments
 324  */
 325 #define BUF             32      /* Maximum length of numeric string. */
 326
 327 /*
 328  * Flags used during conversion.
 329  */
 330 #define LONG            0x01    /* l: long or double */
 331 #define SHORT           0x04    /* h: short */
 332 #define SUPPRESS        0x08    /* suppress assignment */
 333 #define POINTER         0x10    /* weird %p pointer (`fake hex') */
 334 #define NOSKIP          0x20    /* do not skip blanks */
 335 #define QUAD            0x400
 336 #define SHORTSHORT      0x4000  /** hh: char */
 337
 338 /*
 339  * The following are used in numeric conversions only:
 340  * SIGNOK, NDIGITS, DPTOK, and EXPOK are for floating point;
 341  * SIGNOK, NDIGITS, PFXOK, and NZDIGITS are for integral.
 342  */
 343 #define SIGNOK          0x40    /* +/- is (still) legal */
 344 #define NDIGITS         0x80    /* no digits detected */
 345
 346 #define DPTOK           0x100   /* (float) decimal point is still legal */
 347 #define EXPOK           0x200   /* (float) exponent (e+3, etc) still legal */
 348
 349 #define PFXOK           0x100   /* 0x prefix is (still) legal */
 350 #define NZDIGITS        0x200   /* no zero digits detected */
 351
 352 /*
 353  * Conversion types.
 354  */
 355 #define CT_CHAR         0       /* %c conversion */
 356 #define CT_CCL          1       /* %[...] conversion */
 357 #define CT_STRING       2       /* %s conversion */
 358 #define CT_INT          3       /* integer, i.e., strtoq or strtouq */
 359 typedef u64 (*ccfntype)(const char *, char **, int);
 360
 361 int
 362 vsscanf(const char *inp, char const *fmt0, va_list ap)
 363 {
 364         int inr;
 365         const u_char *fmt = (const u_char *)fmt0;
 366         int c;                  /* character from format, or conversion */
 367         size_t width;           /* field width, or 0 */
 368         char *p;                /* points into all kinds of strings */
 369         int n;                  /* handy integer */
 370         int flags;              /* flags as defined above */
 371         char *p0;               /* saves original value of p when necessary */
 372         int nassigned;          /* number of fields assigned */
 373         int nconversions;       /* number of conversions */
 374         int nread;              /* number of characters consumed from fp */
 375         int base;               /* base argument to strtoq/strtouq */
 376         ccfntype ccfn;          /* conversion function (strtoq/strtouq) */
 377         char ccltab[256];       /* character class table for %[...] */
 378         char buf[BUF];          /* buffer for numeric conversions */
 379
 380         /* `basefix' is used to avoid `if' tests in the integer scanner */
 381         static short basefix[17] = { 10, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11,
 382                                      12, 13, 14, 15, 16 };
 383
 384         inr = strlen(inp);
 385
 386         nassigned = 0;
 387         nconversions = 0;
 388         nread = 0;
 389         base = 0;               /* XXX just to keep gcc happy */
 390         ccfn = NULL;            /* XXX just to keep gcc happy */
 391         for (;;) {
 392                 c = *fmt++;
 393                 if (c == 0)
 394                         return (nassigned);
 395                 if (isspace(c)) {
 396                         while (inr > 0 && isspace(*inp))
 397                                 nread++, inr--, inp++;
 398                         continue;
 399                 }
 400                 if (c != '%')
 401                         goto literal;
 402                 width = 0;
 403                 flags = 0;
 404                 /*
 405                  * switch on the format.  continue if done;
 406                  * break once format type is derived.
 407                  */
 408 again:          c = *fmt++;
 409                 switch (c) {
 410                 case '%':
 411 literal:
 412                         if (inr <= 0)
 413                                 goto input_failure;
 414                         if (*inp != c)
 415                                 goto match_failure;
 416                         inr--, inp++;
 417                         nread++;
 418                         continue;
 419
 420                 case '*':
 421                         flags |= SUPPRESS;
 422                         goto again;
 423                 case 'l':
 424                         if (flags & LONG) {
 425                                 flags &= ~LONG;
 426                                 flags |= QUAD;
 427                         } else {
 428                                 flags |= LONG;
 429                         }
 430                         goto again;
 431                 case 'q':
 432                         flags |= QUAD;
 433                         goto again;
 434                 case 'h':
 435                         if (flags & SHORT) {
 436                                 flags &= ~SHORT;
 437                                 flags |= SHORTSHORT;
 438                         } else {
 439                                 flags |= SHORT;
 440                         }
 441                         goto again;
 442
 443                 case '0': case '1': case '2': case '3': case '4':
 444                 case '5': case '6': case '7': case '8': case '9':
 445                         width = width * 10 + c - '0';
 446                         goto again;
 447
 448                 /*
 449                  * Conversions.
 450                  *
 451                  */
 452                 case 'd':
 453                         c = CT_INT;
 454                         ccfn = (ccfntype)strtoq;
 455                         base = 10;
 456                         break;
 457
 458                 case 'i':
 459                         c = CT_INT;
 460                         ccfn = (ccfntype)strtoq;
 461                         base = 0;
 462                         break;
 463
 464                 case 'o':
 465                         c = CT_INT;
 466                         ccfn = strtouq;
 467                         base = 8;
 468                         break;
 469
 470                 case 'u':
 471                         c = CT_INT;
 472                         ccfn = strtouq;
 473                         base = 10;
 474                         break;
 475
 476                 case 'x':
 477                         flags |= PFXOK; /* enable 0x prefixing */
 478                         c = CT_INT;
 479                         ccfn = strtouq;
 480                         base = 16;
 481                         break;
 482
 483                 case 's':
 484                         c = CT_STRING;
 485                         break;
 486
 487                 case '[':
 488                         fmt = __sccl(ccltab, fmt);
 489                         flags |= NOSKIP;
 490                         c = CT_CCL;
 491                         break;
 492
 493                 case 'c':
 494                         flags |= NOSKIP;
 495                         c = CT_CHAR;
 496                         break;
 497
 498                 case 'p':       /* pointer format is like hex */
 499                         flags |= POINTER | PFXOK;
 500                         c = CT_INT;
 501                         ccfn = strtouq;
 502                         base = 16;
 503                         break;
 504
 505                 case 'n':
 506                         nconversions++;
 507                         if (flags & SUPPRESS)   /* ??? */
 508                                 continue;
 509                         if (flags & SHORTSHORT)
 510                                 *va_arg(ap, char *) = nread;
 511                         else if (flags & SHORT)
 512                                 *va_arg(ap, short *) = nread;
 513                         else if (flags & LONG)
 514                                 *va_arg(ap, long *) = nread;
 515                         else if (flags & QUAD)
 516                                 *va_arg(ap, s64 *) = nread;
 517                         else
 518                                 *va_arg(ap, int *) = nread;
 519                         continue;
 520                 }
 521
 522                 /*
 523                  * We have a conversion that requires input.
 524                  */
 525                 if (inr <= 0)
 526                         goto input_failure;
 527
 528                 /*
 529                  * Consume leading white space, except for formats
 530                  * that suppress this.
 531                  */
 532                 if ((flags & NOSKIP) == 0) {
 533                         while (isspace(*inp)) {
 534                                 nread++;
 535                                 if (--inr > 0)
 536                                         inp++;
 537                                 else
 538                                         goto input_failure;
 539                         }
 540                         /*
 541                          * Note that there is at least one character in
 542                          * the buffer, so conversions that do not set NOSKIP
 543                          * can no longer result in an input failure.
 544                          */
 545                 }
 546
 547                 /*
 548                  * Do the conversion.
 549                  */
 550                 switch (c) {
 551                 case CT_CHAR:
 552                         /* scan arbitrary characters (sets NOSKIP) */
 553                         if (width == 0)
 554                                 width = 1;
 555                         if (flags & SUPPRESS) {
 556                                 size_t sum = 0;
 557
 558                                 if ((n = inr) < width) {
 559                                         sum += n;
 560                                         width -= n;
 561                                         inp += n;
 562                                         if (sum == 0)
 563                                                 goto input_failure;
 564                                 } else {
 565                                         sum += width;
 566                                         inr -= width;
 567                                         inp += width;
 568                                 }
 569                                 nread += sum;
 570                         } else {
 571                                 memcpy(va_arg(ap, char *), inp, width);
 572                                 inr -= width;
 573                                 inp += width;
 574                                 nread += width;
 575                                 nassigned++;
 576                         }
 577                         nconversions++;
 578                         break;
 579
 580                 case CT_CCL:
 581                         /* scan a (nonempty) character class (sets NOSKIP) */
 582                         if (width == 0)
 583                                 width = (size_t)~0;     /* `infinity' */
 584                         /* take only those things in the class */
 585                         if (flags & SUPPRESS) {
 586                                 n = 0;
 587                                 while (ccltab[(unsigned char)*inp]) {
 588                                         n++, inr--, inp++;
 589                                         if (--width == 0)
 590                                                 break;
 591                                         if (inr <= 0) {
 592                                                 if (n == 0)
 593                                                         goto input_failure;
 594                                                 break;
 595                                         }
 596                                 }
 597                                 if (n == 0)
 598                                         goto match_failure;
 599                         } else {
 600                                 p = va_arg(ap, char *);
 601                                 p0 = p;
 602                                 while (ccltab[(unsigned char)*inp]) {
 603                                         inr--;
 604                                         *p++ = *inp++;
 605                                         if (--width == 0)
 606                                                 break;
 607                                         if (inr <= 0) {
 608                                                 if (p == p0)
 609                                                         goto input_failure;
 610                                                 break;
 611                                         }
 612                                 }
 613                                 n = p - p0;
 614                                 if (n == 0)
 615                                         goto match_failure;
 616                                 *p = 0;
 617                                 nassigned++;
 618                         }
 619                         nread += n;
 620                         nconversions++;
 621                         break;
 622
 623                 case CT_STRING:
 624                         /* like CCL, but zero-length string OK, & no NOSKIP */
 625                         if (width == 0)
 626                                 width = (size_t)~0;
 627                         if (flags & SUPPRESS) {
 628                                 n = 0;
 629                                 while (!isspace(*inp)) {
 630                                         n++, inr--, inp++;
 631                                         if (--width == 0)
 632                                                 break;
 633                                         if (inr <= 0)
 634                                                 break;
 635                                 }
 636                                 nread += n;
 637                         } else {
 638                                 p = va_arg(ap, char *);
 639                                 p0 = p;
 640                                 while (!isspace(*inp)) {
 641                                         inr--;
 642                                         *p++ = *inp++;
 643                                         if (--width == 0)
 644                                                 break;
 645                                         if (inr <= 0)
 646                                                 break;
 647                                 }
 648                                 *p = 0;
 649                                 nread += p - p0;
 650                                 nassigned++;
 651                         }
 652                         nconversions++;
 653                         continue;
 654
 655                 case CT_INT:
 656                         /* scan an integer as if by strtoq/strtouq */
 657 #ifdef hardway
 658                         if (width == 0 || width > sizeof(buf) - 1)
 659                                 width = sizeof(buf) - 1;
 660 #else
 661                         /* size_t is unsigned, hence this optimisation */
 662                         if (--width > sizeof(buf) - 2)
 663                                 width = sizeof(buf) - 2;
 664                         width++;
 665 #endif
 666                         flags |= SIGNOK | NDIGITS | NZDIGITS;
 667                         for (p = buf; width; width--) {
 668                                 c = *inp;
 669                                 /*
 670                                  * Switch on the character; `goto ok'
 671                                  * if we accept it as a part of number.
 672                                  */
 673                                 switch (c) {
 674                                 /*
 675                                  * The digit 0 is always legal, but is
 676                                  * special.  For %i conversions, if no
 677                                  * digits (zero or nonzero) have been
 678                                  * scanned (only signs), we will have
 679                                  * base==0.  In that case, we should set
 680                                  * it to 8 and enable 0x prefixing.
 681                                  * Also, if we have not scanned zero digits
 682                                  * before this, do not turn off prefixing
 683                                  * (someone else will turn it off if we
 684                                  * have scanned any nonzero digits).
 685                                  */
 686                                 case '0':
 687                                         if (base == 0) {
 688                                                 base = 8;
 689                                                 flags |= PFXOK;
 690                                         }
 691                                         if (flags & NZDIGITS)
 692                                                 flags &= ~(SIGNOK | NZDIGITS | NDIGITS);
 693                                         else
 694                                                 flags &= ~(SIGNOK | PFXOK | NDIGITS);
 695                                         goto ok;
 696
 697                                 /* 1 through 7 always legal */
 698                                 case '1': case '2': case '3':
 699                                 case '4': case '5': case '6': case '7':
 700                                         base = basefix[base];
 701                                         flags &= ~(SIGNOK | PFXOK | NDIGITS);
 702                                         goto ok;
 703
 704                                 /* digits 8 and 9 ok iff decimal or hex */
 705                                 case '8': case '9':
 706                                         base = basefix[base];
 707                                         if (base <= 8)
 708                                                 break;  /* not legal here */
 709                                         flags &= ~(SIGNOK | PFXOK | NDIGITS);
 710                                         goto ok;
 711
 712                                 /* letters ok iff hex */
 713                                 case 'A': case 'B': case 'C':
 714                                 case 'D': case 'E': case 'F':
 715                                 case 'a': case 'b': case 'c':
 716                                 case 'd': case 'e': case 'f':
 717                                         /* no need to fix base here */
 718                                         if (base <= 10)
 719                                                 break;  /* not legal here */
 720                                         flags &= ~(SIGNOK | PFXOK | NDIGITS);
 721                                         goto ok;
 722
 723                                 /* sign ok only as first character */
 724                                 case '+': case '-':
 725                                         if (flags & SIGNOK) {
 726                                                 flags &= ~SIGNOK;
 727                                                 goto ok;
 728                                                 }
 729                                         break;
 730
 731                                 /* x ok iff flag still set & 2nd char */
 732                                 case 'x': case 'X':
 733                                         if (flags & PFXOK && p == buf + 1) {
 734                                                 base = 16;      /* if %i */
 735                                                 flags &= ~PFXOK;
 736                                                 goto ok;
 737                                         }
 738                                         break;
 739                                 }
 740
 741                                 /*
 742                                  * If we got here, c is not a legal character
 743                                  * for a number.  Stop accumulating digits.
 744                                  */
 745                                 break;
 746 ok:
 747                                 /*
 748                                  * c is legal: store it and look at the next.
 749                                  */
 750                                 *p++ = c;
 751                                 if (--inr > 0)
 752                                         inp++;
 753                                 else
 754                                         break;          /* end of input */
 755                         }
 756                         /*
 757                          * If we had only a sign, it is no good; push
 758                          * back the sign.  If the number ends in `x',
 759                          * it was [sign] '' 'x', so push back the x
 760                          * and treat it as [sign] ''.
 761                          */
 762                         if (flags & NDIGITS) {
 763                                 if (p > buf) {
 764                                         inp--;
 765                                         inr++;
 766                                 }
 767                                 goto match_failure;
 768                         }
 769                         c = ((u_char *)p)[-1];
 770                         if (c == 'x' || c == 'X') {
 771                                 --p;
 772                                 inp--;
 773                                 inr++;
 774                         }
 775                         if ((flags & SUPPRESS) == 0) {
 776                                 u64 res;
 777
 778                                 *p = 0;
 779                                 res = (*ccfn)(buf, (char **)NULL, base);
 780                                 if (flags & POINTER)
 781                                         *va_arg(ap, void **) =
 782                                         (void *)(uintptr_t)res;
 783                                 else if (flags & SHORTSHORT)
 784                                         *va_arg(ap, char *) = res;
 785                                 else if (flags & SHORT)
 786                                         *va_arg(ap, short *) = res;
 787                                 else if (flags & LONG)
 788                                         *va_arg(ap, long *) = res;
 789                                 else if (flags & QUAD)
 790                                         *va_arg(ap, s64 *) = res;
 791                                 else
 792                                         *va_arg(ap, int *) = res;
 793                                 nassigned++;
 794                         }
 795                         nread += p - buf;
 796                         nconversions++;
 797                         break;
 798                 }
 799         }
 800 input_failure:
 801                 return (nconversions != 0 ? nassigned : -1);
 802 match_failure:
 803                 return (nassigned);
 804 }
 805
 806 /**
 807  * sscanf - Unformat a buffer into a list of arguments
 808  * @buf:        input buffer
 809  * @fmt:        formatting of buffer
 810  * @...:        resulting arguments
 811  */
 812 int sscanf(const char *buf, const char *fmt, ...)
 813 {
 814         va_list args;
 815         int i;
 816
 817         va_start(args, fmt);
 818         i = vsscanf(buf, fmt, args);
 819         va_end(args);
 820         return i;
 821 }
 822
 823 #endif