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 #include <linux/kallsyms.h>
  26 #include <linux/uaccess.h>
  27
  28 #include <asm/page.h>           /* for PAGE_SIZE */
  29 #include <asm/div64.h>
  30 #include <asm/sections.h>       /* for dereference_function_descriptor() */
  31
  32 /* Works only for digits and letters, but small and fast */
  33 #define TOLOWER(x) ((x) | 0x20)
  34
  35 /**
  36  * simple_strtoul - convert a string to an unsigned long
  37  * @cp: The start of the string
  38  * @endp: A pointer to the end of the parsed string will be placed here
  39  * @base: The number base to use
  40  */
  41 unsigned long simple_strtoul(const char *cp,char **endp,unsigned int base)
  42 {
  43         unsigned long result = 0,value;
  44
  45         if (!base) {
  46                 base = 10;
  47                 if (*cp == '0') {
  48                         base = 8;
  49                         cp++;
  50                         if ((TOLOWER(*cp) == 'x') && isxdigit(cp[1])) {
  51                                 cp++;
  52                                 base = 16;
  53                         }
  54                 }
  55         } else if (base == 16) {
  56                 if (cp[0] == '0' && TOLOWER(cp[1]) == 'x')
  57                         cp += 2;
  58         }
  59         while (isxdigit(*cp) &&
  60                (value = isdigit(*cp) ? *cp-'0' : TOLOWER(*cp)-'a'+10) < base) {
  61                 result = result*base + value;
  62                 cp++;
  63         }
  64         if (endp)
  65                 *endp = (char *)cp;
  66         return result;
  67 }
  68
  69 EXPORT_SYMBOL(simple_strtoul);
  70
  71 /**
  72  * simple_strtol - convert a string to a signed long
  73  * @cp: The start of the string
  74  * @endp: A pointer to the end of the parsed string will be placed here
  75  * @base: The number base to use
  76  */
  77 long simple_strtol(const char *cp,char **endp,unsigned int base)
  78 {
  79         if(*cp=='-')
  80                 return -simple_strtoul(cp+1,endp,base);
  81         return simple_strtoul(cp,endp,base);
  82 }
  83
  84 EXPORT_SYMBOL(simple_strtol);
  85
  86 /**
  87  * simple_strtoull - convert a string to an unsigned long long
  88  * @cp: The start of the string
  89  * @endp: A pointer to the end of the parsed string will be placed here
  90  * @base: The number base to use
  91  */
  92 unsigned long long simple_strtoull(const char *cp,char **endp,unsigned int base)
  93 {
  94         unsigned long long result = 0,value;
  95
  96         if (!base) {
  97                 base = 10;
  98                 if (*cp == '0') {
  99                         base = 8;
 100                         cp++;
 101                         if ((TOLOWER(*cp) == 'x') && isxdigit(cp[1])) {
 102                                 cp++;
 103                                 base = 16;
 104                         }
 105                 }
 106         } else if (base == 16) {
 107                 if (cp[0] == '0' && TOLOWER(cp[1]) == 'x')
 108                         cp += 2;
 109         }
 110         while (isxdigit(*cp)
 111          && (value = isdigit(*cp) ? *cp-'0' : TOLOWER(*cp)-'a'+10) < base) {
 112                 result = result*base + value;
 113                 cp++;
 114         }
 115         if (endp)
 116                 *endp = (char *)cp;
 117         return result;
 118 }
 119
 120 EXPORT_SYMBOL(simple_strtoull);
 121
 122 /**
 123  * simple_strtoll - convert a string to a signed long long
 124  * @cp: The start of the string
 125  * @endp: A pointer to the end of the parsed string will be placed here
 126  * @base: The number base to use
 127  */
 128 long long simple_strtoll(const char *cp,char **endp,unsigned int base)
 129 {
 130         if(*cp=='-')
 131                 return -simple_strtoull(cp+1,endp,base);
 132         return simple_strtoull(cp,endp,base);
 133 }
 134
 135
 136 /**
 137  * strict_strtoul - convert a string to an unsigned long strictly
 138  * @cp: The string to be converted
 139  * @base: The number base to use
 140  * @res: The converted result value
 141  *
 142  * strict_strtoul converts a string to an unsigned long only if the
 143  * string is really an unsigned long string, any string containing
 144  * any invalid char at the tail will be rejected and -EINVAL is returned,
 145  * only a newline char at the tail is acceptible because people generally
 146  * change a module parameter in the following way:
 147  *
 148  *      echo 1024 > /sys/module/e1000/parameters/copybreak
 149  *
 150  * echo will append a newline to the tail.
 151  *
 152  * It returns 0 if conversion is successful and *res is set to the converted
 153  * value, otherwise it returns -EINVAL and *res is set to 0.
 154  *
 155  * simple_strtoul just ignores the successive invalid characters and
 156  * return the converted value of prefix part of the string.
 157  */
 158 int strict_strtoul(const char *cp, unsigned int base, unsigned long *res);
 159
 160 /**
 161  * strict_strtol - convert a string to a long strictly
 162  * @cp: The string to be converted
 163  * @base: The number base to use
 164  * @res: The converted result value
 165  *
 166  * strict_strtol is similiar to strict_strtoul, but it allows the first
 167  * character of a string is '-'.
 168  *
 169  * It returns 0 if conversion is successful and *res is set to the converted
 170  * value, otherwise it returns -EINVAL and *res is set to 0.
 171  */
 172 int strict_strtol(const char *cp, unsigned int base, long *res);
 173
 174 /**
 175  * strict_strtoull - convert a string to an unsigned long long strictly
 176  * @cp: The string to be converted
 177  * @base: The number base to use
 178  * @res: The converted result value
 179  *
 180  * strict_strtoull converts a string to an unsigned long long only if the
 181  * string is really an unsigned long long string, any string containing
 182  * any invalid char at the tail will be rejected and -EINVAL is returned,
 183  * only a newline char at the tail is acceptible because people generally
 184  * change a module parameter in the following way:
 185  *
 186  *      echo 1024 > /sys/module/e1000/parameters/copybreak
 187  *
 188  * echo will append a newline to the tail of the string.
 189  *
 190  * It returns 0 if conversion is successful and *res is set to the converted
 191  * value, otherwise it returns -EINVAL and *res is set to 0.
 192  *
 193  * simple_strtoull just ignores the successive invalid characters and
 194  * return the converted value of prefix part of the string.
 195  */
 196 int strict_strtoull(const char *cp, unsigned int base, unsigned long long *res);
 197
 198 /**
 199  * strict_strtoll - convert a string to a long long strictly
 200  * @cp: The string to be converted
 201  * @base: The number base to use
 202  * @res: The converted result value
 203  *
 204  * strict_strtoll is similiar to strict_strtoull, but it allows the first
 205  * character of a string is '-'.
 206  *
 207  * It returns 0 if conversion is successful and *res is set to the converted
 208  * value, otherwise it returns -EINVAL and *res is set to 0.
 209  */
 210 int strict_strtoll(const char *cp, unsigned int base, long long *res);
 211
 212 #define define_strict_strtoux(type, valtype)                            \
 213 int strict_strtou##type(const char *cp, unsigned int base, valtype *res)\
 214 {                                                                       \
 215         char *tail;                                                     \
 216         valtype val;                                                    \
 217         size_t len;                                                     \
 218                                                                         \
 219         *res = 0;                                                       \
 220         len = strlen(cp);                                               \
 221         if (len == 0)                                                   \
 222                 return -EINVAL;                                         \
 223                                                                         \
 224         val = simple_strtou##type(cp, &tail, base);                     \
 225         if ((*tail == '\0') ||                                          \
 226                 ((len == (size_t)(tail - cp) + 1) && (*tail == '\n'))) {\
 227                 *res = val;                                             \
 228                 return 0;                                               \
 229         }                                                               \
 230                                                                         \
 231         return -EINVAL;                                                 \
 232 }                                                                       \
 233
 234 #define define_strict_strtox(type, valtype)                             \
 235 int strict_strto##type(const char *cp, unsigned int base, valtype *res) \
 236 {                                                                       \
 237         int ret;                                                        \
 238         if (*cp == '-') {                                               \
 239                 ret = strict_strtou##type(cp+1, base, res);             \
 240                 if (!ret)                                               \
 241                         *res = -(*res);                                 \
 242         } else                                                          \
 243                 ret = strict_strtou##type(cp, base, res);               \
 244                                                                         \
 245         return ret;                                                     \
 246 }                                                                       \
 247
 248 define_strict_strtoux(l, unsigned long)
 249 define_strict_strtox(l, long)
 250 define_strict_strtoux(ll, unsigned long long)
 251 define_strict_strtox(ll, long long)
 252
 253 EXPORT_SYMBOL(strict_strtoul);
 254 EXPORT_SYMBOL(strict_strtol);
 255 EXPORT_SYMBOL(strict_strtoll);
 256 EXPORT_SYMBOL(strict_strtoull);
 257
 258 static int skip_atoi(const char **s)
 259 {
 260         int i=0;
 261
 262         while (isdigit(**s))
 263                 i = i*10 + *((*s)++) - '0';
 264         return i;
 265 }
 266
 267 /* Decimal conversion is by far the most typical, and is used
 268  * for /proc and /sys data. This directly impacts e.g. top performance
 269  * with many processes running. We optimize it for speed
 270  * using code from
 271  * http://www.cs.uiowa.edu/~jones/bcd/decimal.html
 272  * (with permission from the author, Douglas W. Jones). */
 273
 274 /* Formats correctly any integer in [0,99999].
 275  * Outputs from one to five digits depending on input.
 276  * On i386 gcc 4.1.2 -O2: ~250 bytes of code. */
 277 static char* put_dec_trunc(char *buf, unsigned q)
 278 {
 279         unsigned d3, d2, d1, d0;
 280         d1 = (q>>4) & 0xf;
 281         d2 = (q>>8) & 0xf;
 282         d3 = (q>>12);
 283
 284         d0 = 6*(d3 + d2 + d1) + (q & 0xf);
 285         q = (d0 * 0xcd) >> 11;
 286         d0 = d0 - 10*q;
 287         *buf++ = d0 + '0'; /* least significant digit */
 288         d1 = q + 9*d3 + 5*d2 + d1;
 289         if (d1 != 0) {
 290                 q = (d1 * 0xcd) >> 11;
 291                 d1 = d1 - 10*q;
 292                 *buf++ = d1 + '0'; /* next digit */
 293
 294                 d2 = q + 2*d2;
 295                 if ((d2 != 0) || (d3 != 0)) {
 296                         q = (d2 * 0xd) >> 7;
 297                         d2 = d2 - 10*q;
 298                         *buf++ = d2 + '0'; /* next digit */
 299
 300                         d3 = q + 4*d3;
 301                         if (d3 != 0) {
 302                                 q = (d3 * 0xcd) >> 11;
 303                                 d3 = d3 - 10*q;
 304                                 *buf++ = d3 + '0';  /* next digit */
 305                                 if (q != 0)
 306                                         *buf++ = q + '0';  /* most sign. digit */
 307                         }
 308                 }
 309         }
 310         return buf;
 311 }
 312 /* Same with if's removed. Always emits five digits */
 313 static char* put_dec_full(char *buf, unsigned q)
 314 {
 315         /* BTW, if q is in [0,9999], 8-bit ints will be enough, */
 316         /* but anyway, gcc produces better code with full-sized ints */
 317         unsigned d3, d2, d1, d0;
 318         d1 = (q>>4) & 0xf;
 319         d2 = (q>>8) & 0xf;
 320         d3 = (q>>12);
 321
 322         /* Possible ways to approx. divide by 10 */
 323         /* gcc -O2 replaces multiply with shifts and adds */
 324         // (x * 0xcd) >> 11: 11001101 - shorter code than * 0x67 (on i386)
 325         // (x * 0x67) >> 10:  1100111
 326         // (x * 0x34) >> 9:    110100 - same
 327         // (x * 0x1a) >> 8:     11010 - same
 328         // (x * 0x0d) >> 7:      1101 - same, shortest code (on i386)
 329
 330         d0 = 6*(d3 + d2 + d1) + (q & 0xf);
 331         q = (d0 * 0xcd) >> 11;
 332         d0 = d0 - 10*q;
 333         *buf++ = d0 + '0';
 334         d1 = q + 9*d3 + 5*d2 + d1;
 335                 q = (d1 * 0xcd) >> 11;
 336                 d1 = d1 - 10*q;
 337                 *buf++ = d1 + '0';
 338
 339                 d2 = q + 2*d2;
 340                         q = (d2 * 0xd) >> 7;
 341                         d2 = d2 - 10*q;
 342                         *buf++ = d2 + '0';
 343
 344                         d3 = q + 4*d3;
 345                                 q = (d3 * 0xcd) >> 11; /* - shorter code */
 346                                 /* q = (d3 * 0x67) >> 10; - would also work */
 347                                 d3 = d3 - 10*q;
 348                                 *buf++ = d3 + '0';
 349                                         *buf++ = q + '0';
 350         return buf;
 351 }
 352 /* No inlining helps gcc to use registers better */
 353 static noinline char* put_dec(char *buf, unsigned long long num)
 354 {
 355         while (1) {
 356                 unsigned rem;
 357                 if (num < 100000)
 358                         return put_dec_trunc(buf, num);
 359                 rem = do_div(num, 100000);
 360                 buf = put_dec_full(buf, rem);
 361         }
 362 }
 363
 364 #define ZEROPAD 1               /* pad with zero */
 365 #define SIGN    2               /* unsigned/signed long */
 366 #define PLUS    4               /* show plus */
 367 #define SPACE   8               /* space if plus */
 368 #define LEFT    16              /* left justified */
 369 #define SMALL   32              /* Must be 32 == 0x20 */
 370 #define SPECIAL 64              /* 0x */
 371
 372 static char *number(char *buf, char *end, unsigned long long num, int base, int size, int precision, int type)
 373 {
 374         /* we are called with base 8, 10 or 16, only, thus don't need "G..."  */
 375         static const char digits[16] = "0123456789ABCDEF"; /* "GHIJKLMNOPQRSTUVWXYZ"; */
 376
 377         char tmp[66];
 378         char sign;
 379         char locase;
 380         int need_pfx = ((type & SPECIAL) && base != 10);
 381         int i;
 382
 383         /* locase = 0 or 0x20. ORing digits or letters with 'locase'
 384          * produces same digits or (maybe lowercased) letters */
 385         locase = (type & SMALL);
 386         if (type & LEFT)
 387                 type &= ~ZEROPAD;
 388         sign = 0;
 389         if (type & SIGN) {
 390                 if ((signed long long) num < 0) {
 391                         sign = '-';
 392                         num = - (signed long long) num;
 393                         size--;
 394                 } else if (type & PLUS) {
 395                         sign = '+';
 396                         size--;
 397                 } else if (type & SPACE) {
 398                         sign = ' ';
 399                         size--;
 400                 }
 401         }
 402         if (need_pfx) {
 403                 size--;
 404                 if (base == 16)
 405                         size--;
 406         }
 407
 408         /* generate full string in tmp[], in reverse order */
 409         i = 0;
 410         if (num == 0)
 411                 tmp[i++] = '0';
 412         /* Generic code, for any base:
 413         else do {
 414                 tmp[i++] = (digits[do_div(num,base)] | locase);
 415         } while (num != 0);
 416         */
 417         else if (base != 10) { /* 8 or 16 */
 418                 int mask = base - 1;
 419                 int shift = 3;
 420                 if (base == 16) shift = 4;
 421                 do {
 422                         tmp[i++] = (digits[((unsigned char)num) & mask] | locase);
 423                         num >>= shift;
 424                 } while (num);
 425         } else { /* base 10 */
 426                 i = put_dec(tmp, num) - tmp;
 427         }
 428
 429         /* printing 100 using %2d gives "100", not "00" */
 430         if (i > precision)
 431                 precision = i;
 432         /* leading space padding */
 433         size -= precision;
 434         if (!(type & (ZEROPAD+LEFT))) {
 435                 while(--size >= 0) {
 436                         if (buf < end)
 437                                 *buf = ' ';
 438                         ++buf;
 439                 }
 440         }
 441         /* sign */
 442         if (sign) {
 443                 if (buf < end)
 444                         *buf = sign;
 445                 ++buf;
 446         }
 447         /* "0x" / "0" prefix */
 448         if (need_pfx) {
 449                 if (buf < end)
 450                         *buf = '0';
 451                 ++buf;
 452                 if (base == 16) {
 453                         if (buf < end)
 454                                 *buf = ('X' | locase);
 455                         ++buf;
 456                 }
 457         }
 458         /* zero or space padding */
 459         if (!(type & LEFT)) {
 460                 char c = (type & ZEROPAD) ? '0' : ' ';
 461                 while (--size >= 0) {
 462                         if (buf < end)
 463                                 *buf = c;
 464                         ++buf;
 465                 }
 466         }
 467         /* hmm even more zero padding? */
 468         while (i <= --precision) {
 469                 if (buf < end)
 470                         *buf = '0';
 471                 ++buf;
 472         }
 473         /* actual digits of result */
 474         while (--i >= 0) {
 475                 if (buf < end)
 476                         *buf = tmp[i];
 477                 ++buf;
 478         }
 479         /* trailing space padding */
 480         while (--size >= 0) {
 481                 if (buf < end)
 482                         *buf = ' ';
 483                 ++buf;
 484         }
 485         return buf;
 486 }
 487
 488 static char *string(char *buf, char *end, char *s, int field_width, int precision, int flags)
 489 {
 490         int len, i;
 491
 492         if ((unsigned long)s < PAGE_SIZE)
 493                 s = "<NULL>";
 494
 495         len = strnlen(s, precision);
 496
 497         if (!(flags & LEFT)) {
 498                 while (len < field_width--) {
 499                         if (buf < end)
 500                                 *buf = ' ';
 501                         ++buf;
 502                 }
 503         }
 504         for (i = 0; i < len; ++i) {
 505                 if (buf < end)
 506                         *buf = *s;
 507                 ++buf; ++s;
 508         }
 509         while (len < field_width--) {
 510                 if (buf < end)
 511                         *buf = ' ';
 512                 ++buf;
 513         }
 514         return buf;
 515 }
 516
 517 static char *symbol_string(char *buf, char *end, void *ptr, int field_width, int precision, int flags)
 518 {
 519         unsigned long value = (unsigned long) ptr;
 520 #ifdef CONFIG_KALLSYMS
 521         char sym[KSYM_SYMBOL_LEN];
 522         sprint_symbol(sym, value);
 523         return string(buf, end, sym, field_width, precision, flags);
 524 #else
 525         field_width = 2*sizeof(void *);
 526         flags |= SPECIAL | SMALL | ZEROPAD;
 527         return number(buf, end, value, 16, field_width, precision, flags);
 528 #endif
 529 }
 530
 531 /*
 532  * Show a '%p' thing.  A kernel extension is that the '%p' is followed
 533  * by an extra set of alphanumeric characters that are extended format
 534  * specifiers.
 535  *
 536  * Right now we just handle 'F' (for symbolic Function descriptor pointers)
 537  * and 'S' (for Symbolic direct pointers), but this can easily be
 538  * extended in the future (network address types etc).
 539  *
 540  * The difference between 'S' and 'F' is that on ia64 and ppc64 function
 541  * pointers are really function descriptors, which contain a pointer the
 542  * real address.
 543  */
 544 static char *pointer(const char *fmt, char *buf, char *end, void *ptr, int field_width, int precision, int flags)
 545 {
 546         switch (*fmt) {
 547         case 'F':
 548                 ptr = dereference_function_descriptor(ptr);
 549                 /* Fallthrough */
 550         case 'S':
 551                 return symbol_string(buf, end, ptr, field_width, precision, flags);
 552         }
 553         flags |= SMALL;
 554         if (field_width == -1) {
 555                 field_width = 2*sizeof(void *);
 556                 flags |= ZEROPAD;
 557         }
 558         return number(buf, end, (unsigned long) ptr, 16, field_width, precision, flags);
 559 }
 560
 561 /**
 562  * vsnprintf - Format a string and place it in a buffer
 563  * @buf: The buffer to place the result into
 564  * @size: The size of the buffer, including the trailing null space
 565  * @fmt: The format string to use
 566  * @args: Arguments for the format string
 567  *
 568  * The return value is the number of characters which would
 569  * be generated for the given input, excluding the trailing
 570  * '\0', as per ISO C99. If you want to have the exact
 571  * number of characters written into @buf as return value
 572  * (not including the trailing '\0'), use vscnprintf(). If the
 573  * return is greater than or equal to @size, the resulting
 574  * string is truncated.
 575  *
 576  * Call this function if you are already dealing with a va_list.
 577  * You probably want snprintf() instead.
 578  */
 579 int vsnprintf(char *buf, size_t size, const char *fmt, va_list args)
 580 {
 581         unsigned long long num;
 582         int base;
 583         char *str, *end, c;
 584
 585         int flags;              /* flags to number() */
 586
 587         int field_width;        /* width of output field */
 588         int precision;          /* min. # of digits for integers; max
 589                                    number of chars for from string */
 590         int qualifier;          /* 'h', 'l', or 'L' for integer fields */
 591                                 /* 'z' support added 23/7/1999 S.H.    */
 592                                 /* 'z' changed to 'Z' --davidm 1/25/99 */
 593                                 /* 't' added for ptrdiff_t */
 594
 595         /* Reject out-of-range values early.  Large positive sizes are
 596            used for unknown buffer sizes. */
 597         if (unlikely((int) size < 0)) {
 598                 /* There can be only one.. */
 599                 static char warn = 1;
 600                 WARN_ON(warn);
 601                 warn = 0;
 602                 return 0;
 603         }
 604
 605         str = buf;
 606         end = buf + size;
 607
 608         /* Make sure end is always >= buf */
 609         if (end < buf) {
 610                 end = ((void *)-1);
 611                 size = end - buf;
 612         }
 613
 614         for (; *fmt ; ++fmt) {
 615                 if (*fmt != '%') {
 616                         if (str < end)
 617                                 *str = *fmt;
 618                         ++str;
 619                         continue;
 620                 }
 621
 622                 /* process flags */
 623                 flags = 0;
 624                 repeat:
 625                         ++fmt;          /* this also skips first '%' */
 626                         switch (*fmt) {
 627                                 case '-': flags |= LEFT; goto repeat;
 628                                 case '+': flags |= PLUS; goto repeat;
 629                                 case ' ': flags |= SPACE; goto repeat;
 630                                 case '#': flags |= SPECIAL; goto repeat;
 631                                 case '0': flags |= ZEROPAD; goto repeat;
 632                         }
 633
 634                 /* get field width */
 635                 field_width = -1;
 636                 if (isdigit(*fmt))
 637                         field_width = skip_atoi(&fmt);
 638                 else if (*fmt == '*') {
 639                         ++fmt;
 640                         /* it's the next argument */
 641                         field_width = va_arg(args, int);
 642                         if (field_width < 0) {
 643                                 field_width = -field_width;
 644                                 flags |= LEFT;
 645                         }
 646                 }
 647
 648                 /* get the precision */
 649                 precision = -1;
 650                 if (*fmt == '.') {
 651                         ++fmt;
 652                         if (isdigit(*fmt))
 653                                 precision = skip_atoi(&fmt);
 654                         else if (*fmt == '*') {
 655                                 ++fmt;
 656                                 /* it's the next argument */
 657                                 precision = va_arg(args, int);
 658                         }
 659                         if (precision < 0)
 660                                 precision = 0;
 661                 }
 662
 663                 /* get the conversion qualifier */
 664                 qualifier = -1;
 665                 if (*fmt == 'h' || *fmt == 'l' || *fmt == 'L' ||
 666                     *fmt =='Z' || *fmt == 'z' || *fmt == 't') {
 667                         qualifier = *fmt;
 668                         ++fmt;
 669                         if (qualifier == 'l' && *fmt == 'l') {
 670                                 qualifier = 'L';
 671                                 ++fmt;
 672                         }
 673                 }
 674
 675                 /* default base */
 676                 base = 10;
 677
 678                 switch (*fmt) {
 679                         case 'c':
 680                                 if (!(flags & LEFT)) {
 681                                         while (--field_width > 0) {
 682                                                 if (str < end)
 683                                                         *str = ' ';
 684                                                 ++str;
 685                                         }
 686                                 }
 687                                 c = (unsigned char) va_arg(args, int);
 688                                 if (str < end)
 689                                         *str = c;
 690                                 ++str;
 691                                 while (--field_width > 0) {
 692                                         if (str < end)
 693                                                 *str = ' ';
 694                                         ++str;
 695                                 }
 696                                 continue;
 697
 698                         case 's':
 699                                 str = string(str, end, va_arg(args, char *), field_width, precision, flags);
 700                                 continue;
 701
 702                         case 'p':
 703                                 str = pointer(fmt+1, str, end,
 704                                                 va_arg(args, void *),
 705                                                 field_width, precision, flags);
 706                                 /* Skip all alphanumeric pointer suffixes */
 707                                 while (isalnum(fmt[1]))
 708                                         fmt++;
 709                                 continue;
 710
 711                         case 'n':
 712                                 /* FIXME:
 713                                 * What does C99 say about the overflow case here? */
 714                                 if (qualifier == 'l') {
 715                                         long * ip = va_arg(args, long *);
 716                                         *ip = (str - buf);
 717                                 } else if (qualifier == 'Z' || qualifier == 'z') {
 718                                         size_t * ip = va_arg(args, size_t *);
 719                                         *ip = (str - buf);
 720                                 } else {
 721                                         int * ip = va_arg(args, int *);
 722                                         *ip = (str - buf);
 723                                 }
 724                                 continue;
 725
 726                         case '%':
 727                                 if (str < end)
 728                                         *str = '%';
 729                                 ++str;
 730                                 continue;
 731
 732                                 /* integer number formats - set up the flags and "break" */
 733                         case 'o':
 734                                 base = 8;
 735                                 break;
 736
 737                         case 'x':
 738                                 flags |= SMALL;
 739                         case 'X':
 740                                 base = 16;
 741                                 break;
 742
 743                         case 'd':
 744                         case 'i':
 745                                 flags |= SIGN;
 746                         case 'u':
 747                                 break;
 748
 749                         default:
 750                                 if (str < end)
 751                                         *str = '%';
 752                                 ++str;
 753                                 if (*fmt) {
 754                                         if (str < end)
 755                                                 *str = *fmt;
 756                                         ++str;
 757                                 } else {
 758                                         --fmt;
 759                                 }
 760                                 continue;
 761                 }
 762                 if (qualifier == 'L')
 763                         num = va_arg(args, long long);
 764                 else if (qualifier == 'l') {
 765                         num = va_arg(args, unsigned long);
 766                         if (flags & SIGN)
 767                                 num = (signed long) num;
 768                 } else if (qualifier == 'Z' || qualifier == 'z') {
 769                         num = va_arg(args, size_t);
 770                 } else if (qualifier == 't') {
 771                         num = va_arg(args, ptrdiff_t);
 772                 } else if (qualifier == 'h') {
 773                         num = (unsigned short) va_arg(args, int);
 774                         if (flags & SIGN)
 775                                 num = (signed short) num;
 776                 } else {
 777                         num = va_arg(args, unsigned int);
 778                         if (flags & SIGN)
 779                                 num = (signed int) num;
 780                 }
 781                 str = number(str, end, num, base,
 782                                 field_width, precision, flags);
 783         }
 784         if (size > 0) {
 785                 if (str < end)
 786                         *str = '\0';
 787                 else
 788                         end[-1] = '\0';
 789         }
 790         /* the trailing null byte doesn't count towards the total */
 791         return str-buf;
 792 }
 793
 794 EXPORT_SYMBOL(vsnprintf);
 795
 796 /**
 797  * vscnprintf - Format a string and place it in a buffer
 798  * @buf: The buffer to place the result into
 799  * @size: The size of the buffer, including the trailing null space
 800  * @fmt: The format string to use
 801  * @args: Arguments for the format string
 802  *
 803  * The return value is the number of characters which have been written into
 804  * the @buf not including the trailing '\0'. If @size is <= 0 the function
 805  * returns 0.
 806  *
 807  * Call this function if you are already dealing with a va_list.
 808  * You probably want scnprintf() instead.
 809  */
 810 int vscnprintf(char *buf, size_t size, const char *fmt, va_list args)
 811 {
 812         int i;
 813
 814         i=vsnprintf(buf,size,fmt,args);
 815         return (i >= size) ? (size - 1) : i;
 816 }
 817
 818 EXPORT_SYMBOL(vscnprintf);
 819
 820 /**
 821  * snprintf - Format a string and place it in a buffer
 822  * @buf: The buffer to place the result into
 823  * @size: The size of the buffer, including the trailing null space
 824  * @fmt: The format string to use
 825  * @...: Arguments for the format string
 826  *
 827  * The return value is the number of characters which would be
 828  * generated for the given input, excluding the trailing null,
 829  * as per ISO C99.  If the return is greater than or equal to
 830  * @size, the resulting string is truncated.
 831  */
 832 int snprintf(char * buf, size_t size, const char *fmt, ...)
 833 {
 834         va_list args;
 835         int i;
 836
 837         va_start(args, fmt);
 838         i=vsnprintf(buf,size,fmt,args);
 839         va_end(args);
 840         return i;
 841 }
 842
 843 EXPORT_SYMBOL(snprintf);
 844
 845 /**
 846  * scnprintf - Format a string and place it in a buffer
 847  * @buf: The buffer to place the result into
 848  * @size: The size of the buffer, including the trailing null space
 849  * @fmt: The format string to use
 850  * @...: Arguments for the format string
 851  *
 852  * The return value is the number of characters written into @buf not including
 853  * the trailing '\0'. If @size is <= 0 the function returns 0.
 854  */
 855
 856 int scnprintf(char * buf, size_t size, const char *fmt, ...)
 857 {
 858         va_list args;
 859         int i;
 860
 861         va_start(args, fmt);
 862         i = vsnprintf(buf, size, fmt, args);
 863         va_end(args);
 864         return (i >= size) ? (size - 1) : i;
 865 }
 866 EXPORT_SYMBOL(scnprintf);
 867
 868 /**
 869  * vsprintf - Format a string and place it in a buffer
 870  * @buf: The buffer to place the result into
 871  * @fmt: The format string to use
 872  * @args: Arguments for the format string
 873  *
 874  * The function returns the number of characters written
 875  * into @buf. Use vsnprintf() or vscnprintf() in order to avoid
 876  * buffer overflows.
 877  *
 878  * Call this function if you are already dealing with a va_list.
 879  * You probably want sprintf() instead.
 880  */
 881 int vsprintf(char *buf, const char *fmt, va_list args)
 882 {
 883         return vsnprintf(buf, INT_MAX, fmt, args);
 884 }
 885
 886 EXPORT_SYMBOL(vsprintf);
 887
 888 /**
 889  * sprintf - Format a string and place it in a buffer
 890  * @buf: The buffer to place the result into
 891  * @fmt: The format string to use
 892  * @...: Arguments for the format string
 893  *
 894  * The function returns the number of characters written
 895  * into @buf. Use snprintf() or scnprintf() in order to avoid
 896  * buffer overflows.
 897  */
 898 int sprintf(char * buf, const char *fmt, ...)
 899 {
 900         va_list args;
 901         int i;
 902
 903         va_start(args, fmt);
 904         i=vsnprintf(buf, INT_MAX, fmt, args);
 905         va_end(args);
 906         return i;
 907 }
 908
 909 EXPORT_SYMBOL(sprintf);
 910
 911 /**
 912  * vsscanf - Unformat a buffer into a list of arguments
 913  * @buf:        input buffer
 914  * @fmt:        format of buffer
 915  * @args:       arguments
 916  */
 917 int vsscanf(const char * buf, const char * fmt, va_list args)
 918 {
 919         const char *str = buf;
 920         char *next;
 921         char digit;
 922         int num = 0;
 923         int qualifier;
 924         int base;
 925         int field_width;
 926         int is_sign = 0;
 927
 928         while(*fmt && *str) {
 929                 /* skip any white space in format */
 930                 /* white space in format matchs any amount of
 931                  * white space, including none, in the input.
 932                  */
 933                 if (isspace(*fmt)) {
 934                         while (isspace(*fmt))
 935                                 ++fmt;
 936                         while (isspace(*str))
 937                                 ++str;
 938                 }
 939
 940                 /* anything that is not a conversion must match exactly */
 941                 if (*fmt != '%' && *fmt) {
 942                         if (*fmt++ != *str++)
 943                                 break;
 944                         continue;
 945                 }
 946
 947                 if (!*fmt)
 948                         break;
 949                 ++fmt;
 950
 951                 /* skip this conversion.
 952                  * advance both strings to next white space
 953                  */
 954                 if (*fmt == '*') {
 955                         while (!isspace(*fmt) && *fmt)
 956                                 fmt++;
 957                         while (!isspace(*str) && *str)
 958                                 str++;
 959                         continue;
 960                 }
 961
 962                 /* get field width */
 963                 field_width = -1;
 964                 if (isdigit(*fmt))
 965                         field_width = skip_atoi(&fmt);
 966
 967                 /* get conversion qualifier */
 968                 qualifier = -1;
 969                 if (*fmt == 'h' || *fmt == 'l' || *fmt == 'L' ||
 970                     *fmt == 'Z' || *fmt == 'z') {
 971                         qualifier = *fmt++;
 972                         if (unlikely(qualifier == *fmt)) {
 973                                 if (qualifier == 'h') {
 974                                         qualifier = 'H';
 975                                         fmt++;
 976                                 } else if (qualifier == 'l') {
 977                                         qualifier = 'L';
 978                                         fmt++;
 979                                 }
 980                         }
 981                 }
 982                 base = 10;
 983                 is_sign = 0;
 984
 985                 if (!*fmt || !*str)
 986                         break;
 987
 988                 switch(*fmt++) {
 989                 case 'c':
 990                 {
 991                         char *s = (char *) va_arg(args,char*);
 992                         if (field_width == -1)
 993                                 field_width = 1;
 994                         do {
 995                                 *s++ = *str++;
 996                         } while (--field_width > 0 && *str);
 997                         num++;
 998                 }
 999                 continue;
1000                 case 's':
1001                 {
1002                         char *s = (char *) va_arg(args, char *);
1003                         if(field_width == -1)
1004                                 field_width = INT_MAX;
1005                         /* first, skip leading white space in buffer */
1006                         while (isspace(*str))
1007                                 str++;
1008
1009                         /* now copy until next white space */
1010                         while (*str && !isspace(*str) && field_width--) {
1011                                 *s++ = *str++;
1012                         }
1013                         *s = '\0';
1014                         num++;
1015                 }
1016                 continue;
1017                 case 'n':
1018                         /* return number of characters read so far */
1019                 {
1020                         int *i = (int *)va_arg(args,int*);
1021                         *i = str - buf;
1022                 }
1023                 continue;
1024                 case 'o':
1025                         base = 8;
1026                         break;
1027                 case 'x':
1028                 case 'X':
1029                         base = 16;
1030                         break;
1031                 case 'i':
1032                         base = 0;
1033                 case 'd':
1034                         is_sign = 1;
1035                 case 'u':
1036                         break;
1037                 case '%':
1038                         /* looking for '%' in str */
1039                         if (*str++ != '%')
1040                                 return num;
1041                         continue;
1042                 default:
1043                         /* invalid format; stop here */
1044                         return num;
1045                 }
1046
1047                 /* have some sort of integer conversion.
1048                  * first, skip white space in buffer.
1049                  */
1050                 while (isspace(*str))
1051                         str++;
1052
1053                 digit = *str;
1054                 if (is_sign && digit == '-')
1055                         digit = *(str + 1);
1056
1057                 if (!digit
1058                     || (base == 16 && !isxdigit(digit))
1059                     || (base == 10 && !isdigit(digit))
1060                     || (base == 8 && (!isdigit(digit) || digit > '7'))
1061                     || (base == 0 && !isdigit(digit)))
1062                                 break;
1063
1064                 switch(qualifier) {
1065                 case 'H':       /* that's 'hh' in format */
1066                         if (is_sign) {
1067                                 signed char *s = (signed char *) va_arg(args,signed char *);
1068                                 *s = (signed char) simple_strtol(str,&next,base);
1069                         } else {
1070                                 unsigned char *s = (unsigned char *) va_arg(args, unsigned char *);
1071                                 *s = (unsigned char) simple_strtoul(str, &next, base);
1072                         }
1073                         break;
1074                 case 'h':
1075                         if (is_sign) {
1076                                 short *s = (short *) va_arg(args,short *);
1077                                 *s = (short) simple_strtol(str,&next,base);
1078                         } else {
1079                                 unsigned short *s = (unsigned short *) va_arg(args, unsigned short *);
1080                                 *s = (unsigned short) simple_strtoul(str, &next, base);
1081                         }
1082                         break;
1083                 case 'l':
1084                         if (is_sign) {
1085                                 long *l = (long *) va_arg(args,long *);
1086                                 *l = simple_strtol(str,&next,base);
1087                         } else {
1088                                 unsigned long *l = (unsigned long*) va_arg(args,unsigned long*);
1089                                 *l = simple_strtoul(str,&next,base);
1090                         }
1091                         break;
1092                 case 'L':
1093                         if (is_sign) {
1094                                 long long *l = (long long*) va_arg(args,long long *);
1095                                 *l = simple_strtoll(str,&next,base);
1096                         } else {
1097                                 unsigned long long *l = (unsigned long long*) va_arg(args,unsigned long long*);
1098                                 *l = simple_strtoull(str,&next,base);
1099                         }
1100                         break;
1101                 case 'Z':
1102                 case 'z':
1103                 {
1104                         size_t *s = (size_t*) va_arg(args,size_t*);
1105                         *s = (size_t) simple_strtoul(str,&next,base);
1106                 }
1107                 break;
1108                 default:
1109                         if (is_sign) {
1110                                 int *i = (int *) va_arg(args, int*);
1111                                 *i = (int) simple_strtol(str,&next,base);
1112                         } else {
1113                                 unsigned int *i = (unsigned int*) va_arg(args, unsigned int*);
1114                                 *i = (unsigned int) simple_strtoul(str,&next,base);
1115                         }
1116                         break;
1117                 }
1118                 num++;
1119
1120                 if (!next)
1121                         break;
1122                 str = next;
1123         }
1124
1125         /*
1126          * Now we've come all the way through so either the input string or the
1127          * format ended. In the former case, there can be a %n at the current
1128          * position in the format that needs to be filled.
1129          */
1130         if (*fmt == '%' && *(fmt + 1) == 'n') {
1131                 int *p = (int *)va_arg(args, int *);
1132                 *p = str - buf;
1133         }
1134
1135         return num;
1136 }
1137
1138 EXPORT_SYMBOL(vsscanf);
1139
1140 /**
1141  * sscanf - Unformat a buffer into a list of arguments
1142  * @buf:        input buffer
1143  * @fmt:        formatting of buffer
1144  * @...:        resulting arguments
1145  */
1146 int sscanf(const char * buf, const char * fmt, ...)
1147 {
1148         va_list args;
1149         int i;
1150
1151         va_start(args,fmt);
1152         i = vsscanf(buf,fmt,args);
1153         va_end(args);
1154         return i;
1155 }
1156
1157 EXPORT_SYMBOL(sscanf);