lib/vsprintf.c

   1 /*
   2  *  linux/lib/vsprintf.c
   3  *
   4  *  Copyright (C) 1991, 1992  Linus Torvalds
   5  */
   6
   7 /* vsprintf.c -- Lars Wirzenius & Linus Torvalds. */
   8 /*
   9  * Wirzenius wrote this portably, Torvalds fucked it up :-)
  10  */
  11
  12 /*
  13  * Fri Jul 13 2001 Crutcher Dunnavant <crutcher+kernel@datastacks.com>
  14  * - changed to provide snprintf and vsnprintf functions
  15  * So Feb  1 16:51:32 CET 2004 Juergen Quade <quade@hsnr.de>
  16  * - scnprintf and vscnprintf
  17  */
  18
  19 #include <stdarg.h>
  20 #include <linux/module.h>
  21 #include <linux/types.h>
  22 #include <linux/string.h>
  23 #include <linux/ctype.h>
  24 #include <linux/kernel.h>
  25
  26 #include <asm/page.h>           /* for PAGE_SIZE */
  27 #include <asm/div64.h>
  28
  29 /**
  30  * simple_strtoul - convert a string to an unsigned long
  31  * @cp: The start of the string
  32  * @endp: A pointer to the end of the parsed string will be placed here
  33  * @base: The number base to use
  34  */
  35 unsigned long simple_strtoul(const char *cp,char **endp,unsigned int base)
  36 {
  37         unsigned long result = 0,value;
  38
  39         if (!base) {
  40                 base = 10;
  41                 if (*cp == '0') {
  42                         base = 8;
  43                         cp++;
  44                         if ((toupper(*cp) == 'X') && isxdigit(cp[1])) {
  45                                 cp++;
  46                                 base = 16;
  47                         }
  48                 }
  49         } else if (base == 16) {
  50                 if (cp[0] == '0' && toupper(cp[1]) == 'X')
  51                         cp += 2;
  52         }
  53         while (isxdigit(*cp) &&
  54                (value = isdigit(*cp) ? *cp-'0' : toupper(*cp)-'A'+10) < base) {
  55                 result = result*base + value;
  56                 cp++;
  57         }
  58         if (endp)
  59                 *endp = (char *)cp;
  60         return result;
  61 }
  62
  63 EXPORT_SYMBOL(simple_strtoul);
  64
  65 /**
  66  * simple_strtol - convert a string to a signed long
  67  * @cp: The start of the string
  68  * @endp: A pointer to the end of the parsed string will be placed here
  69  * @base: The number base to use
  70  */
  71 long simple_strtol(const char *cp,char **endp,unsigned int base)
  72 {
  73         if(*cp=='-')
  74                 return -simple_strtoul(cp+1,endp,base);
  75         return simple_strtoul(cp,endp,base);
  76 }
  77
  78 EXPORT_SYMBOL(simple_strtol);
  79
  80 /**
  81  * simple_strtoull - convert a string to an unsigned long long
  82  * @cp: The start of the string
  83  * @endp: A pointer to the end of the parsed string will be placed here
  84  * @base: The number base to use
  85  */
  86 unsigned long long simple_strtoull(const char *cp,char **endp,unsigned int base)
  87 {
  88         unsigned long long result = 0,value;
  89
  90         if (!base) {
  91                 base = 10;
  92                 if (*cp == '0') {
  93                         base = 8;
  94                         cp++;
  95                         if ((toupper(*cp) == 'X') && isxdigit(cp[1])) {
  96                                 cp++;
  97                                 base = 16;
  98                         }
  99                 }
 100         } else if (base == 16) {
 101                 if (cp[0] == '0' && toupper(cp[1]) == 'X')
 102                         cp += 2;
 103         }
 104         while (isxdigit(*cp) && (value = isdigit(*cp) ? *cp-'0' : (islower(*cp)
 105             ? toupper(*cp) : *cp)-'A'+10) < base) {
 106                 result = result*base + value;
 107                 cp++;
 108         }
 109         if (endp)
 110                 *endp = (char *)cp;
 111         return result;
 112 }
 113
 114 EXPORT_SYMBOL(simple_strtoull);
 115
 116 /**
 117  * simple_strtoll - convert a string to a signed long long
 118  * @cp: The start of the string
 119  * @endp: A pointer to the end of the parsed string will be placed here
 120  * @base: The number base to use
 121  */
 122 long long simple_strtoll(const char *cp,char **endp,unsigned int base)
 123 {
 124         if(*cp=='-')
 125                 return -simple_strtoull(cp+1,endp,base);
 126         return simple_strtoull(cp,endp,base);
 127 }
 128
 129 static int skip_atoi(const char **s)
 130 {
 131         int i=0;
 132
 133         while (isdigit(**s))
 134                 i = i*10 + *((*s)++) - '0';
 135         return i;
 136 }
 137
 138 /* Decimal conversion is by far the most typical, and is used
 139  * for /proc and /sys data. This directly impacts e.g. top performance
 140  * with many processes running. We optimize it for speed
 141  * using code from
 142  * http://www.cs.uiowa.edu/~jones/bcd/decimal.html
 143  * (with permission from the author, Douglas W. Jones). */
 144
 145 /* Formats correctly any integer in [0,99999].
 146  * Outputs from one to five digits depending on input.
 147  * On i386 gcc 4.1.2 -O2: ~250 bytes of code. */
 148 static char* put_dec_trunc(char *buf, unsigned q)
 149 {
 150         unsigned d3, d2, d1, d0;
 151         d1 = (q>>4) & 0xf;
 152         d2 = (q>>8) & 0xf;
 153         d3 = (q>>12);
 154
 155         d0 = 6*(d3 + d2 + d1) + (q & 0xf);
 156         q = (d0 * 0xcd) >> 11;
 157         d0 = d0 - 10*q;
 158         *buf++ = d0 + '0'; /* least significant digit */
 159         d1 = q + 9*d3 + 5*d2 + d1;
 160         if (d1 != 0) {
 161                 q = (d1 * 0xcd) >> 11;
 162                 d1 = d1 - 10*q;
 163                 *buf++ = d1 + '0'; /* next digit */
 164
 165                 d2 = q + 2*d2;
 166                 if ((d2 != 0) || (d3 != 0)) {
 167                         q = (d2 * 0xd) >> 7;
 168                         d2 = d2 - 10*q;
 169                         *buf++ = d2 + '0'; /* next digit */
 170
 171                         d3 = q + 4*d3;
 172                         if (d3 != 0) {
 173                                 q = (d3 * 0xcd) >> 11;
 174                                 d3 = d3 - 10*q;
 175                                 *buf++ = d3 + '0';  /* next digit */
 176                                 if (q != 0)
 177                                         *buf++ = q + '0';  /* most sign. digit */
 178                         }
 179                 }
 180         }
 181         return buf;
 182 }
 183 /* Same with if's removed. Always emits five digits */
 184 static char* put_dec_full(char *buf, unsigned q)
 185 {
 186         /* BTW, if q is in [0,9999], 8-bit ints will be enough, */
 187         /* but anyway, gcc produces better code with full-sized ints */
 188         unsigned d3, d2, d1, d0;
 189         d1 = (q>>4) & 0xf;
 190         d2 = (q>>8) & 0xf;
 191         d3 = (q>>12);
 192
 193         /* Possible ways to approx. divide by 10 */
 194         /* gcc -O2 replaces multiply with shifts and adds */
 195         // (x * 0xcd) >> 11: 11001101 - shorter code than * 0x67 (on i386)
 196         // (x * 0x67) >> 10:  1100111
 197         // (x * 0x34) >> 9:    110100 - same
 198         // (x * 0x1a) >> 8:     11010 - same
 199         // (x * 0x0d) >> 7:      1101 - same, shortest code (on i386)
 200
 201         d0 = 6*(d3 + d2 + d1) + (q & 0xf);
 202         q = (d0 * 0xcd) >> 11;
 203         d0 = d0 - 10*q;
 204         *buf++ = d0 + '0';
 205         d1 = q + 9*d3 + 5*d2 + d1;
 206                 q = (d1 * 0xcd) >> 11;
 207                 d1 = d1 - 10*q;
 208                 *buf++ = d1 + '0';
 209
 210                 d2 = q + 2*d2;
 211                         q = (d2 * 0xd) >> 7;
 212                         d2 = d2 - 10*q;
 213                         *buf++ = d2 + '0';
 214
 215                         d3 = q + 4*d3;
 216                                 q = (d3 * 0xcd) >> 11; /* - shorter code */
 217                                 /* q = (d3 * 0x67) >> 10; - would also work */
 218                                 d3 = d3 - 10*q;
 219                                 *buf++ = d3 + '0';
 220                                         *buf++ = q + '0';
 221         return buf;
 222 }
 223 /* No inlining helps gcc to use registers better */
 224 static noinline char* put_dec(char *buf, unsigned long long num)
 225 {
 226         while (1) {
 227                 unsigned rem;
 228                 if (num < 100000)
 229                         return put_dec_trunc(buf, num);
 230                 rem = do_div(num, 100000);
 231                 buf = put_dec_full(buf, rem);
 232         }
 233 }
 234
 235 #define ZEROPAD 1               /* pad with zero */
 236 #define SIGN    2               /* unsigned/signed long */
 237 #define PLUS    4               /* show plus */
 238 #define SPACE   8               /* space if plus */
 239 #define LEFT    16              /* left justified */
 240 #define SPECIAL 32              /* 0x */
 241 #define LARGE   64              /* use 'ABCDEF' instead of 'abcdef' */
 242
 243 static char *number(char *buf, char *end, unsigned long long num, int base, int size, int precision, int type)
 244 {
 245         char sign,tmp[66];
 246         const char *digits;
 247         /* we are called with base 8, 10 or 16, only, thus don't need "g..."  */
 248         static const char small_digits[] = "0123456789abcdefx"; /* "ghijklmnopqrstuvwxyz"; */
 249         static const char large_digits[] = "0123456789ABCDEFX"; /* "GHIJKLMNOPQRSTUVWXYZ"; */
 250         int need_pfx = ((type & SPECIAL) && base != 10);
 251         int i;
 252
 253         digits = (type & LARGE) ? large_digits : small_digits;
 254         if (type & LEFT)
 255                 type &= ~ZEROPAD;
 256         if (base < 2 || base > 36)
 257                 return NULL;
 258         sign = 0;
 259         if (type & SIGN) {
 260                 if ((signed long long) num < 0) {
 261                         sign = '-';
 262                         num = - (signed long long) num;
 263                         size--;
 264                 } else if (type & PLUS) {
 265                         sign = '+';
 266                         size--;
 267                 } else if (type & SPACE) {
 268                         sign = ' ';
 269                         size--;
 270                 }
 271         }
 272         if (need_pfx) {
 273                 size--;
 274                 if (base == 16)
 275                         size--;
 276         }
 277
 278         /* generate full string in tmp[], in reverse order */
 279         i = 0;
 280         if (num == 0)
 281                 tmp[i++] = '0';
 282         /* Generic code, for any base:
 283         else do {
 284                 tmp[i++] = digits[do_div(num,base)];
 285         } while (num != 0);
 286         */
 287         else if (base != 10) { /* 8 or 16 */
 288                 int mask = base - 1;
 289                 int shift = 3;
 290                 if (base == 16) shift = 4;
 291                 do {
 292                         tmp[i++] = digits[((unsigned char)num) & mask];
 293                         num >>= shift;
 294                 } while (num);
 295         } else { /* base 10 */
 296                 i = put_dec(tmp, num) - tmp;
 297         }
 298
 299         /* printing 100 using %2d gives "100", not "00" */
 300         if (i > precision)
 301                 precision = i;
 302         /* leading space padding */
 303         size -= precision;
 304         if (!(type & (ZEROPAD+LEFT))) {
 305                 while(--size >= 0) {
 306                         if (buf < end)
 307                                 *buf = ' ';
 308                         ++buf;
 309                 }
 310         }
 311         /* sign */
 312         if (sign) {
 313                 if (buf < end)
 314                         *buf = sign;
 315                 ++buf;
 316         }
 317         /* "0x" / "0" prefix */
 318         if (need_pfx) {
 319                 if (buf < end)
 320                         *buf = '0';
 321                 ++buf;
 322                 if (base == 16) {
 323                         if (buf < end)
 324                                 *buf = digits[16]; /* for arbitrary base: digits[33]; */
 325                         ++buf;
 326                 }
 327         }
 328         /* zero or space padding */
 329         if (!(type & LEFT)) {
 330                 char c = (type & ZEROPAD) ? '0' : ' ';
 331                 while (--size >= 0) {
 332                         if (buf < end)
 333                                 *buf = c;
 334                         ++buf;
 335                 }
 336         }
 337         /* hmm even more zero padding? */
 338         while (i <= --precision) {
 339                 if (buf < end)
 340                         *buf = '0';
 341                 ++buf;
 342         }
 343         /* actual digits of result */
 344         while (--i >= 0) {
 345                 if (buf < end)
 346                         *buf = tmp[i];
 347                 ++buf;
 348         }
 349         /* trailing space padding */
 350         while (--size >= 0) {
 351                 if (buf < end)
 352                         *buf = ' ';
 353                 ++buf;
 354         }
 355         return buf;
 356 }
 357
 358 /**
 359  * vsnprintf - Format a string and place it in a buffer
 360  * @buf: The buffer to place the result into
 361  * @size: The size of the buffer, including the trailing null space
 362  * @fmt: The format string to use
 363  * @args: Arguments for the format string
 364  *
 365  * The return value is the number of characters which would
 366  * be generated for the given input, excluding the trailing
 367  * '\0', as per ISO C99. If you want to have the exact
 368  * number of characters written into @buf as return value
 369  * (not including the trailing '\0'), use vscnprintf(). If the
 370  * return is greater than or equal to @size, the resulting
 371  * string is truncated.
 372  *
 373  * Call this function if you are already dealing with a va_list.
 374  * You probably want snprintf() instead.
 375  */
 376 int vsnprintf(char *buf, size_t size, const char *fmt, va_list args)
 377 {
 378         int len;
 379         unsigned long long num;
 380         int i, base;
 381         char *str, *end, c;
 382         const char *s;
 383
 384         int flags;              /* flags to number() */
 385
 386         int field_width;        /* width of output field */
 387         int precision;          /* min. # of digits for integers; max
 388                                    number of chars for from string */
 389         int qualifier;          /* 'h', 'l', or 'L' for integer fields */
 390                                 /* 'z' support added 23/7/1999 S.H.    */
 391                                 /* 'z' changed to 'Z' --davidm 1/25/99 */
 392                                 /* 't' added for ptrdiff_t */
 393
 394         /* Reject out-of-range values early.  Large positive sizes are
 395            used for unknown buffer sizes. */
 396         if (unlikely((int) size < 0)) {
 397                 /* There can be only one.. */
 398                 static char warn = 1;
 399                 WARN_ON(warn);
 400                 warn = 0;
 401                 return 0;
 402         }
 403
 404         str = buf;
 405         end = buf + size;
 406
 407         /* Make sure end is always >= buf */
 408         if (end < buf) {
 409                 end = ((void *)-1);
 410                 size = end - buf;
 411         }
 412
 413         for (; *fmt ; ++fmt) {
 414                 if (*fmt != '%') {
 415                         if (str < end)
 416                                 *str = *fmt;
 417                         ++str;
 418                         continue;
 419                 }
 420
 421                 /* process flags */
 422                 flags = 0;
 423                 repeat:
 424                         ++fmt;          /* this also skips first '%' */
 425                         switch (*fmt) {
 426                                 case '-': flags |= LEFT; goto repeat;
 427                                 case '+': flags |= PLUS; goto repeat;
 428                                 case ' ': flags |= SPACE; goto repeat;
 429                                 case '#': flags |= SPECIAL; goto repeat;
 430                                 case '0': flags |= ZEROPAD; goto repeat;
 431                         }
 432
 433                 /* get field width */
 434                 field_width = -1;
 435                 if (isdigit(*fmt))
 436                         field_width = skip_atoi(&fmt);
 437                 else if (*fmt == '*') {
 438                         ++fmt;
 439                         /* it's the next argument */
 440                         field_width = va_arg(args, int);
 441                         if (field_width < 0) {
 442                                 field_width = -field_width;
 443                                 flags |= LEFT;
 444                         }
 445                 }
 446
 447                 /* get the precision */
 448                 precision = -1;
 449                 if (*fmt == '.') {
 450                         ++fmt;
 451                         if (isdigit(*fmt))
 452                                 precision = skip_atoi(&fmt);
 453                         else if (*fmt == '*') {
 454                                 ++fmt;
 455                                 /* it's the next argument */
 456                                 precision = va_arg(args, int);
 457                         }
 458                         if (precision < 0)
 459                                 precision = 0;
 460                 }
 461
 462                 /* get the conversion qualifier */
 463                 qualifier = -1;
 464                 if (*fmt == 'h' || *fmt == 'l' || *fmt == 'L' ||
 465                     *fmt =='Z' || *fmt == 'z' || *fmt == 't') {
 466                         qualifier = *fmt;
 467                         ++fmt;
 468                         if (qualifier == 'l' && *fmt == 'l') {
 469                                 qualifier = 'L';
 470                                 ++fmt;
 471                         }
 472                 }
 473
 474                 /* default base */
 475                 base = 10;
 476
 477                 switch (*fmt) {
 478                         case 'c':
 479                                 if (!(flags & LEFT)) {
 480                                         while (--field_width > 0) {
 481                                                 if (str < end)
 482                                                         *str = ' ';
 483                                                 ++str;
 484                                         }
 485                                 }
 486                                 c = (unsigned char) va_arg(args, int);
 487                                 if (str < end)
 488                                         *str = c;
 489                                 ++str;
 490                                 while (--field_width > 0) {
 491                                         if (str < end)
 492                                                 *str = ' ';
 493                                         ++str;
 494                                 }
 495                                 continue;
 496
 497                         case 's':
 498                                 s = va_arg(args, char *);
 499                                 if ((unsigned long)s < PAGE_SIZE)
 500                                         s = "<NULL>";
 501
 502                                 len = strnlen(s, precision);
 503
 504                                 if (!(flags & LEFT)) {
 505                                         while (len < field_width--) {
 506                                                 if (str < end)
 507                                                         *str = ' ';
 508                                                 ++str;
 509                                         }
 510                                 }
 511                                 for (i = 0; i < len; ++i) {
 512                                         if (str < end)
 513                                                 *str = *s;
 514                                         ++str; ++s;
 515                                 }
 516                                 while (len < field_width--) {
 517                                         if (str < end)
 518                                                 *str = ' ';
 519                                         ++str;
 520                                 }
 521                                 continue;
 522
 523                         case 'p':
 524                                 if (field_width == -1) {
 525                                         field_width = 2*sizeof(void *);
 526                                         flags |= ZEROPAD;
 527                                 }
 528                                 str = number(str, end,
 529                                                 (unsigned long) va_arg(args, void *),
 530                                                 16, field_width, precision, flags);
 531                                 continue;
 532
 533
 534                         case 'n':
 535                                 /* FIXME:
 536                                 * What does C99 say about the overflow case here? */
 537                                 if (qualifier == 'l') {
 538                                         long * ip = va_arg(args, long *);
 539                                         *ip = (str - buf);
 540                                 } else if (qualifier == 'Z' || qualifier == 'z') {
 541                                         size_t * ip = va_arg(args, size_t *);
 542                                         *ip = (str - buf);
 543                                 } else {
 544                                         int * ip = va_arg(args, int *);
 545                                         *ip = (str - buf);
 546                                 }
 547                                 continue;
 548
 549                         case '%':
 550                                 if (str < end)
 551                                         *str = '%';
 552                                 ++str;
 553                                 continue;
 554
 555                                 /* integer number formats - set up the flags and "break" */
 556                         case 'o':
 557                                 base = 8;
 558                                 break;
 559
 560                         case 'X':
 561                                 flags |= LARGE;
 562                         case 'x':
 563                                 base = 16;
 564                                 break;
 565
 566                         case 'd':
 567                         case 'i':
 568                                 flags |= SIGN;
 569                         case 'u':
 570                                 break;
 571
 572                         default:
 573                                 if (str < end)
 574                                         *str = '%';
 575                                 ++str;
 576                                 if (*fmt) {
 577                                         if (str < end)
 578                                                 *str = *fmt;
 579                                         ++str;
 580                                 } else {
 581                                         --fmt;
 582                                 }
 583                                 continue;
 584                 }
 585                 if (qualifier == 'L')
 586                         num = va_arg(args, long long);
 587                 else if (qualifier == 'l') {
 588                         num = va_arg(args, unsigned long);
 589                         if (flags & SIGN)
 590                                 num = (signed long) num;
 591                 } else if (qualifier == 'Z' || qualifier == 'z') {
 592                         num = va_arg(args, size_t);
 593                 } else if (qualifier == 't') {
 594                         num = va_arg(args, ptrdiff_t);
 595                 } else if (qualifier == 'h') {
 596                         num = (unsigned short) va_arg(args, int);
 597                         if (flags & SIGN)
 598                                 num = (signed short) num;
 599                 } else {
 600                         num = va_arg(args, unsigned int);
 601                         if (flags & SIGN)
 602                                 num = (signed int) num;
 603                 }
 604                 str = number(str, end, num, base,
 605                                 field_width, precision, flags);
 606         }
 607         if (size > 0) {
 608                 if (str < end)
 609                         *str = '\0';
 610                 else
 611                         end[-1] = '\0';
 612         }
 613         /* the trailing null byte doesn't count towards the total */
 614         return str-buf;
 615 }
 616
 617 EXPORT_SYMBOL(vsnprintf);
 618
 619 /**
 620  * vscnprintf - Format a string and place it in a buffer
 621  * @buf: The buffer to place the result into
 622  * @size: The size of the buffer, including the trailing null space
 623  * @fmt: The format string to use
 624  * @args: Arguments for the format string
 625  *
 626  * The return value is the number of characters which have been written into
 627  * the @buf not including the trailing '\0'. If @size is <= 0 the function
 628  * returns 0.
 629  *
 630  * Call this function if you are already dealing with a va_list.
 631  * You probably want scnprintf() instead.
 632  */
 633 int vscnprintf(char *buf, size_t size, const char *fmt, va_list args)
 634 {
 635         int i;
 636
 637         i=vsnprintf(buf,size,fmt,args);
 638         return (i >= size) ? (size - 1) : i;
 639 }
 640
 641 EXPORT_SYMBOL(vscnprintf);
 642
 643 /**
 644  * snprintf - Format a string and place it in a buffer
 645  * @buf: The buffer to place the result into
 646  * @size: The size of the buffer, including the trailing null space
 647  * @fmt: The format string to use
 648  * @...: Arguments for the format string
 649  *
 650  * The return value is the number of characters which would be
 651  * generated for the given input, excluding the trailing null,
 652  * as per ISO C99.  If the return is greater than or equal to
 653  * @size, the resulting string is truncated.
 654  */
 655 int snprintf(char * buf, size_t size, const char *fmt, ...)
 656 {
 657         va_list args;
 658         int i;
 659
 660         va_start(args, fmt);
 661         i=vsnprintf(buf,size,fmt,args);
 662         va_end(args);
 663         return i;
 664 }
 665
 666 EXPORT_SYMBOL(snprintf);
 667
 668 /**
 669  * scnprintf - Format a string and place it in a buffer
 670  * @buf: The buffer to place the result into
 671  * @size: The size of the buffer, including the trailing null space
 672  * @fmt: The format string to use
 673  * @...: Arguments for the format string
 674  *
 675  * The return value is the number of characters written into @buf not including
 676  * the trailing '\0'. If @size is <= 0 the function returns 0.
 677  */
 678
 679 int scnprintf(char * buf, size_t size, const char *fmt, ...)
 680 {
 681         va_list args;
 682         int i;
 683
 684         va_start(args, fmt);
 685         i = vsnprintf(buf, size, fmt, args);
 686         va_end(args);
 687         return (i >= size) ? (size - 1) : i;
 688 }
 689 EXPORT_SYMBOL(scnprintf);
 690
 691 /**
 692  * vsprintf - Format a string and place it in a buffer
 693  * @buf: The buffer to place the result into
 694  * @fmt: The format string to use
 695  * @args: Arguments for the format string
 696  *
 697  * The function returns the number of characters written
 698  * into @buf. Use vsnprintf() or vscnprintf() in order to avoid
 699  * buffer overflows.
 700  *
 701  * Call this function if you are already dealing with a va_list.
 702  * You probably want sprintf() instead.
 703  */
 704 int vsprintf(char *buf, const char *fmt, va_list args)
 705 {
 706         return vsnprintf(buf, INT_MAX, fmt, args);
 707 }
 708
 709 EXPORT_SYMBOL(vsprintf);
 710
 711 /**
 712  * sprintf - Format a string and place it in a buffer
 713  * @buf: The buffer to place the result into
 714  * @fmt: The format string to use
 715  * @...: Arguments for the format string
 716  *
 717  * The function returns the number of characters written
 718  * into @buf. Use snprintf() or scnprintf() in order to avoid
 719  * buffer overflows.
 720  */
 721 int sprintf(char * buf, const char *fmt, ...)
 722 {
 723         va_list args;
 724         int i;
 725
 726         va_start(args, fmt);
 727         i=vsnprintf(buf, INT_MAX, fmt, args);
 728         va_end(args);
 729         return i;
 730 }
 731
 732 EXPORT_SYMBOL(sprintf);
 733
 734 /**
 735  * vsscanf - Unformat a buffer into a list of arguments
 736  * @buf:        input buffer
 737  * @fmt:        format of buffer
 738  * @args:       arguments
 739  */
 740 int vsscanf(const char * buf, const char * fmt, va_list args)
 741 {
 742         const char *str = buf;
 743         char *next;
 744         char digit;
 745         int num = 0;
 746         int qualifier;
 747         int base;
 748         int field_width;
 749         int is_sign = 0;
 750
 751         while(*fmt && *str) {
 752                 /* skip any white space in format */
 753                 /* white space in format matchs any amount of
 754                  * white space, including none, in the input.
 755                  */
 756                 if (isspace(*fmt)) {
 757                         while (isspace(*fmt))
 758                                 ++fmt;
 759                         while (isspace(*str))
 760                                 ++str;
 761                 }
 762
 763                 /* anything that is not a conversion must match exactly */
 764                 if (*fmt != '%' && *fmt) {
 765                         if (*fmt++ != *str++)
 766                                 break;
 767                         continue;
 768                 }
 769
 770                 if (!*fmt)
 771                         break;
 772                 ++fmt;
 773
 774                 /* skip this conversion.
 775                  * advance both strings to next white space
 776                  */
 777                 if (*fmt == '*') {
 778                         while (!isspace(*fmt) && *fmt)
 779                                 fmt++;
 780                         while (!isspace(*str) && *str)
 781                                 str++;
 782                         continue;
 783                 }
 784
 785                 /* get field width */
 786                 field_width = -1;
 787                 if (isdigit(*fmt))
 788                         field_width = skip_atoi(&fmt);
 789
 790                 /* get conversion qualifier */
 791                 qualifier = -1;
 792                 if (*fmt == 'h' || *fmt == 'l' || *fmt == 'L' ||
 793                     *fmt == 'Z' || *fmt == 'z') {
 794                         qualifier = *fmt++;
 795                         if (unlikely(qualifier == *fmt)) {
 796                                 if (qualifier == 'h') {
 797                                         qualifier = 'H';
 798                                         fmt++;
 799                                 } else if (qualifier == 'l') {
 800                                         qualifier = 'L';
 801                                         fmt++;
 802                                 }
 803                         }
 804                 }
 805                 base = 10;
 806                 is_sign = 0;
 807
 808                 if (!*fmt || !*str)
 809                         break;
 810
 811                 switch(*fmt++) {
 812                 case 'c':
 813                 {
 814                         char *s = (char *) va_arg(args,char*);
 815                         if (field_width == -1)
 816                                 field_width = 1;
 817                         do {
 818                                 *s++ = *str++;
 819                         } while (--field_width > 0 && *str);
 820                         num++;
 821                 }
 822                 continue;
 823                 case 's':
 824                 {
 825                         char *s = (char *) va_arg(args, char *);
 826                         if(field_width == -1)
 827                                 field_width = INT_MAX;
 828                         /* first, skip leading white space in buffer */
 829                         while (isspace(*str))
 830                                 str++;
 831
 832                         /* now copy until next white space */
 833                         while (*str && !isspace(*str) && field_width--) {
 834                                 *s++ = *str++;
 835                         }
 836                         *s = '\0';
 837                         num++;
 838                 }
 839                 continue;
 840                 case 'n':
 841                         /* return number of characters read so far */
 842                 {
 843                         int *i = (int *)va_arg(args,int*);
 844                         *i = str - buf;
 845                 }
 846                 continue;
 847                 case 'o':
 848                         base = 8;
 849                         break;
 850                 case 'x':
 851                 case 'X':
 852                         base = 16;
 853                         break;
 854                 case 'i':
 855                         base = 0;
 856                 case 'd':
 857                         is_sign = 1;
 858                 case 'u':
 859                         break;
 860                 case '%':
 861                         /* looking for '%' in str */
 862                         if (*str++ != '%')
 863                                 return num;
 864                         continue;
 865                 default:
 866                         /* invalid format; stop here */
 867                         return num;
 868                 }
 869
 870                 /* have some sort of integer conversion.
 871                  * first, skip white space in buffer.
 872                  */
 873                 while (isspace(*str))
 874                         str++;
 875
 876                 digit = *str;
 877                 if (is_sign && digit == '-')
 878                         digit = *(str + 1);
 879
 880                 if (!digit
 881                     || (base == 16 && !isxdigit(digit))
 882                     || (base == 10 && !isdigit(digit))
 883                     || (base == 8 && (!isdigit(digit) || digit > '7'))
 884                     || (base == 0 && !isdigit(digit)))
 885                                 break;
 886
 887                 switch(qualifier) {
 888                 case 'H':       /* that's 'hh' in format */
 889                         if (is_sign) {
 890                                 signed char *s = (signed char *) va_arg(args,signed char *);
 891                                 *s = (signed char) simple_strtol(str,&next,base);
 892                         } else {
 893                                 unsigned char *s = (unsigned char *) va_arg(args, unsigned char *);
 894                                 *s = (unsigned char) simple_strtoul(str, &next, base);
 895                         }
 896                         break;
 897                 case 'h':
 898                         if (is_sign) {
 899                                 short *s = (short *) va_arg(args,short *);
 900                                 *s = (short) simple_strtol(str,&next,base);
 901                         } else {
 902                                 unsigned short *s = (unsigned short *) va_arg(args, unsigned short *);
 903                                 *s = (unsigned short) simple_strtoul(str, &next, base);
 904                         }
 905                         break;
 906                 case 'l':
 907                         if (is_sign) {
 908                                 long *l = (long *) va_arg(args,long *);
 909                                 *l = simple_strtol(str,&next,base);
 910                         } else {
 911                                 unsigned long *l = (unsigned long*) va_arg(args,unsigned long*);
 912                                 *l = simple_strtoul(str,&next,base);
 913                         }
 914                         break;
 915                 case 'L':
 916                         if (is_sign) {
 917                                 long long *l = (long long*) va_arg(args,long long *);
 918                                 *l = simple_strtoll(str,&next,base);
 919                         } else {
 920                                 unsigned long long *l = (unsigned long long*) va_arg(args,unsigned long long*);
 921                                 *l = simple_strtoull(str,&next,base);
 922                         }
 923                         break;
 924                 case 'Z':
 925                 case 'z':
 926                 {
 927                         size_t *s = (size_t*) va_arg(args,size_t*);
 928                         *s = (size_t) simple_strtoul(str,&next,base);
 929                 }
 930                 break;
 931                 default:
 932                         if (is_sign) {
 933                                 int *i = (int *) va_arg(args, int*);
 934                                 *i = (int) simple_strtol(str,&next,base);
 935                         } else {
 936                                 unsigned int *i = (unsigned int*) va_arg(args, unsigned int*);
 937                                 *i = (unsigned int) simple_strtoul(str,&next,base);
 938                         }
 939                         break;
 940                 }
 941                 num++;
 942
 943                 if (!next)
 944                         break;
 945                 str = next;
 946         }
 947
 948         /*
 949          * Now we've come all the way through so either the input string or the
 950          * format ended. In the former case, there can be a %n at the current
 951          * position in the format that needs to be filled.
 952          */
 953         if (*fmt == '%' && *(fmt + 1) == 'n') {
 954                 int *p = (int *)va_arg(args, int *);
 955                 *p = str - buf;
 956         }
 957
 958         return num;
 959 }
 960
 961 EXPORT_SYMBOL(vsscanf);
 962
 963 /**
 964  * sscanf - Unformat a buffer into a list of arguments
 965  * @buf:        input buffer
 966  * @fmt:        formatting of buffer
 967  * @...:        resulting arguments
 968  */
 969 int sscanf(const char * buf, const char * fmt, ...)
 970 {
 971         va_list args;
 972         int i;
 973
 974         va_start(args,fmt);
 975         i = vsscanf(buf,fmt,args);
 976         va_end(args);
 977         return i;
 978 }
 979
 980 EXPORT_SYMBOL(sscanf);