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 #include <linux/ioport.h>
  28
  29 #include <asm/page.h>           /* for PAGE_SIZE */
  30 #include <asm/div64.h>
  31 #include <asm/sections.h>       /* for dereference_function_descriptor() */
  32
  33 /* Works only for digits and letters, but small and fast */
  34 #define TOLOWER(x) ((x) | 0x20)
  35
  36 static unsigned int simple_guess_base(const char *cp)
  37 {
  38         if (cp[0] == '0') {
  39                 if (TOLOWER(cp[1]) == 'x' && isxdigit(cp[2]))
  40                         return 16;
  41                 else
  42                         return 8;
  43         } else {
  44                 return 10;
  45         }
  46 }
  47
  48 /**
  49  * simple_strtoul - convert a string to an unsigned long
  50  * @cp: The start of the string
  51  * @endp: A pointer to the end of the parsed string will be placed here
  52  * @base: The number base to use
  53  */
  54 unsigned long simple_strtoul(const char *cp, char **endp, unsigned int base)
  55 {
  56         unsigned long result = 0;
  57
  58         if (!base)
  59                 base = simple_guess_base(cp);
  60
  61         if (base == 16 && cp[0] == '0' && TOLOWER(cp[1]) == 'x')
  62                 cp += 2;
  63
  64         while (isxdigit(*cp)) {
  65                 unsigned int value;
  66
  67                 value = isdigit(*cp) ? *cp - '0' : TOLOWER(*cp) - 'a' + 10;
  68                 if (value >= base)
  69                         break;
  70                 result = result * base + value;
  71                 cp++;
  72         }
  73
  74         if (endp)
  75                 *endp = (char *)cp;
  76         return result;
  77 }
  78 EXPORT_SYMBOL(simple_strtoul);
  79
  80 /**
  81  * simple_strtol - convert a string to a signed 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 long simple_strtol(const char *cp, char **endp, unsigned int base)
  87 {
  88         if(*cp == '-')
  89                 return -simple_strtoul(cp + 1, endp, base);
  90         return simple_strtoul(cp, endp, base);
  91 }
  92 EXPORT_SYMBOL(simple_strtol);
  93
  94 /**
  95  * simple_strtoull - convert a string to an unsigned long long
  96  * @cp: The start of the string
  97  * @endp: A pointer to the end of the parsed string will be placed here
  98  * @base: The number base to use
  99  */
 100 unsigned long long simple_strtoull(const char *cp, char **endp, unsigned int base)
 101 {
 102         unsigned long long result = 0;
 103
 104         if (!base)
 105                 base = simple_guess_base(cp);
 106
 107         if (base == 16 && cp[0] == '0' && TOLOWER(cp[1]) == 'x')
 108                 cp += 2;
 109
 110         while (isxdigit(*cp)) {
 111                 unsigned int value;
 112
 113                 value = isdigit(*cp) ? *cp - '0' : TOLOWER(*cp) - 'a' + 10;
 114                 if (value >= base)
 115                         break;
 116                 result = result * base + value;
 117                 cp++;
 118         }
 119
 120         if (endp)
 121                 *endp = (char *)cp;
 122         return result;
 123 }
 124 EXPORT_SYMBOL(simple_strtoull);
 125
 126 /**
 127  * simple_strtoll - convert a string to a signed long long
 128  * @cp: The start of the string
 129  * @endp: A pointer to the end of the parsed string will be placed here
 130  * @base: The number base to use
 131  */
 132 long long simple_strtoll(const char *cp, char **endp, unsigned int base)
 133 {
 134         if(*cp=='-')
 135                 return -simple_strtoull(cp + 1, endp, base);
 136         return simple_strtoull(cp, endp, base);
 137 }
 138
 139 /**
 140  * strict_strtoul - convert a string to an unsigned long strictly
 141  * @cp: The string to be converted
 142  * @base: The number base to use
 143  * @res: The converted result value
 144  *
 145  * strict_strtoul converts a string to an unsigned long only if the
 146  * string is really an unsigned long string, any string containing
 147  * any invalid char at the tail will be rejected and -EINVAL is returned,
 148  * only a newline char at the tail is acceptible because people generally
 149  * change a module parameter in the following way:
 150  *
 151  *      echo 1024 > /sys/module/e1000/parameters/copybreak
 152  *
 153  * echo will append a newline to the tail.
 154  *
 155  * It returns 0 if conversion is successful and *res is set to the converted
 156  * value, otherwise it returns -EINVAL and *res is set to 0.
 157  *
 158  * simple_strtoul just ignores the successive invalid characters and
 159  * return the converted value of prefix part of the string.
 160  */
 161 int strict_strtoul(const char *cp, unsigned int base, unsigned long *res)
 162 {
 163         char *tail;
 164         unsigned long val;
 165         size_t len;
 166
 167         *res = 0;
 168         len = strlen(cp);
 169         if (len == 0)
 170                 return -EINVAL;
 171
 172         val = simple_strtoul(cp, &tail, base);
 173         if ((*tail == '\0') ||
 174                 ((len == (size_t)(tail - cp) + 1) && (*tail == '\n'))) {
 175                 *res = val;
 176                 return 0;
 177         }
 178
 179         return -EINVAL;
 180 }
 181 EXPORT_SYMBOL(strict_strtoul);
 182
 183 /**
 184  * strict_strtol - convert a string to a long strictly
 185  * @cp: The string to be converted
 186  * @base: The number base to use
 187  * @res: The converted result value
 188  *
 189  * strict_strtol is similiar to strict_strtoul, but it allows the first
 190  * character of a string is '-'.
 191  *
 192  * It returns 0 if conversion is successful and *res is set to the converted
 193  * value, otherwise it returns -EINVAL and *res is set to 0.
 194  */
 195 int strict_strtol(const char *cp, unsigned int base, long *res)
 196 {
 197         int ret;
 198         if (*cp == '-') {
 199                 ret = strict_strtoul(cp + 1, base, (unsigned long *)res);
 200                 if (!ret)
 201                         *res = -(*res);
 202         } else {
 203                 ret = strict_strtoul(cp, base, (unsigned long *)res);
 204         }
 205
 206         return ret;
 207 }
 208 EXPORT_SYMBOL(strict_strtol);
 209
 210 /**
 211  * strict_strtoull - convert a string to an unsigned long long strictly
 212  * @cp: The string to be converted
 213  * @base: The number base to use
 214  * @res: The converted result value
 215  *
 216  * strict_strtoull converts a string to an unsigned long long only if the
 217  * string is really an unsigned long long string, any string containing
 218  * any invalid char at the tail will be rejected and -EINVAL is returned,
 219  * only a newline char at the tail is acceptible because people generally
 220  * change a module parameter in the following way:
 221  *
 222  *      echo 1024 > /sys/module/e1000/parameters/copybreak
 223  *
 224  * echo will append a newline to the tail of the string.
 225  *
 226  * It returns 0 if conversion is successful and *res is set to the converted
 227  * value, otherwise it returns -EINVAL and *res is set to 0.
 228  *
 229  * simple_strtoull just ignores the successive invalid characters and
 230  * return the converted value of prefix part of the string.
 231  */
 232 int strict_strtoull(const char *cp, unsigned int base, unsigned long long *res)
 233 {
 234         char *tail;
 235         unsigned long long val;
 236         size_t len;
 237
 238         *res = 0;
 239         len = strlen(cp);
 240         if (len == 0)
 241                 return -EINVAL;
 242
 243         val = simple_strtoull(cp, &tail, base);
 244         if ((*tail == '\0') ||
 245                 ((len == (size_t)(tail - cp) + 1) && (*tail == '\n'))) {
 246                 *res = val;
 247                 return 0;
 248         }
 249
 250         return -EINVAL;
 251 }
 252 EXPORT_SYMBOL(strict_strtoull);
 253
 254 /**
 255  * strict_strtoll - convert a string to a long long strictly
 256  * @cp: The string to be converted
 257  * @base: The number base to use
 258  * @res: The converted result value
 259  *
 260  * strict_strtoll is similiar to strict_strtoull, but it allows the first
 261  * character of a string is '-'.
 262  *
 263  * It returns 0 if conversion is successful and *res is set to the converted
 264  * value, otherwise it returns -EINVAL and *res is set to 0.
 265  */
 266 int strict_strtoll(const char *cp, unsigned int base, long long *res)
 267 {
 268         int ret;
 269         if (*cp == '-') {
 270                 ret = strict_strtoull(cp + 1, base, (unsigned long long *)res);
 271                 if (!ret)
 272                         *res = -(*res);
 273         } else {
 274                 ret = strict_strtoull(cp, base, (unsigned long long *)res);
 275         }
 276
 277         return ret;
 278 }
 279 EXPORT_SYMBOL(strict_strtoll);
 280
 281 static int skip_atoi(const char **s)
 282 {
 283         int i=0;
 284
 285         while (isdigit(**s))
 286                 i = i*10 + *((*s)++) - '0';
 287         return i;
 288 }
 289
 290 /* Decimal conversion is by far the most typical, and is used
 291  * for /proc and /sys data. This directly impacts e.g. top performance
 292  * with many processes running. We optimize it for speed
 293  * using code from
 294  * http://www.cs.uiowa.edu/~jones/bcd/decimal.html
 295  * (with permission from the author, Douglas W. Jones). */
 296
 297 /* Formats correctly any integer in [0,99999].
 298  * Outputs from one to five digits depending on input.
 299  * On i386 gcc 4.1.2 -O2: ~250 bytes of code. */
 300 static char* put_dec_trunc(char *buf, unsigned q)
 301 {
 302         unsigned d3, d2, d1, d0;
 303         d1 = (q>>4) & 0xf;
 304         d2 = (q>>8) & 0xf;
 305         d3 = (q>>12);
 306
 307         d0 = 6*(d3 + d2 + d1) + (q & 0xf);
 308         q = (d0 * 0xcd) >> 11;
 309         d0 = d0 - 10*q;
 310         *buf++ = d0 + '0'; /* least significant digit */
 311         d1 = q + 9*d3 + 5*d2 + d1;
 312         if (d1 != 0) {
 313                 q = (d1 * 0xcd) >> 11;
 314                 d1 = d1 - 10*q;
 315                 *buf++ = d1 + '0'; /* next digit */
 316
 317                 d2 = q + 2*d2;
 318                 if ((d2 != 0) || (d3 != 0)) {
 319                         q = (d2 * 0xd) >> 7;
 320                         d2 = d2 - 10*q;
 321                         *buf++ = d2 + '0'; /* next digit */
 322
 323                         d3 = q + 4*d3;
 324                         if (d3 != 0) {
 325                                 q = (d3 * 0xcd) >> 11;
 326                                 d3 = d3 - 10*q;
 327                                 *buf++ = d3 + '0';  /* next digit */
 328                                 if (q != 0)
 329                                         *buf++ = q + '0';  /* most sign. digit */
 330                         }
 331                 }
 332         }
 333         return buf;
 334 }
 335 /* Same with if's removed. Always emits five digits */
 336 static char* put_dec_full(char *buf, unsigned q)
 337 {
 338         /* BTW, if q is in [0,9999], 8-bit ints will be enough, */
 339         /* but anyway, gcc produces better code with full-sized ints */
 340         unsigned d3, d2, d1, d0;
 341         d1 = (q>>4) & 0xf;
 342         d2 = (q>>8) & 0xf;
 343         d3 = (q>>12);
 344
 345         /* Possible ways to approx. divide by 10 */
 346         /* gcc -O2 replaces multiply with shifts and adds */
 347         // (x * 0xcd) >> 11: 11001101 - shorter code than * 0x67 (on i386)
 348         // (x * 0x67) >> 10:  1100111
 349         // (x * 0x34) >> 9:    110100 - same
 350         // (x * 0x1a) >> 8:     11010 - same
 351         // (x * 0x0d) >> 7:      1101 - same, shortest code (on i386)
 352
 353         d0 = 6*(d3 + d2 + d1) + (q & 0xf);
 354         q = (d0 * 0xcd) >> 11;
 355         d0 = d0 - 10*q;
 356         *buf++ = d0 + '0';
 357         d1 = q + 9*d3 + 5*d2 + d1;
 358                 q = (d1 * 0xcd) >> 11;
 359                 d1 = d1 - 10*q;
 360                 *buf++ = d1 + '0';
 361
 362                 d2 = q + 2*d2;
 363                         q = (d2 * 0xd) >> 7;
 364                         d2 = d2 - 10*q;
 365                         *buf++ = d2 + '0';
 366
 367                         d3 = q + 4*d3;
 368                                 q = (d3 * 0xcd) >> 11; /* - shorter code */
 369                                 /* q = (d3 * 0x67) >> 10; - would also work */
 370                                 d3 = d3 - 10*q;
 371                                 *buf++ = d3 + '0';
 372                                         *buf++ = q + '0';
 373         return buf;
 374 }
 375 /* No inlining helps gcc to use registers better */
 376 static noinline char* put_dec(char *buf, unsigned long long num)
 377 {
 378         while (1) {
 379                 unsigned rem;
 380                 if (num < 100000)
 381                         return put_dec_trunc(buf, num);
 382                 rem = do_div(num, 100000);
 383                 buf = put_dec_full(buf, rem);
 384         }
 385 }
 386
 387 #define ZEROPAD 1               /* pad with zero */
 388 #define SIGN    2               /* unsigned/signed long */
 389 #define PLUS    4               /* show plus */
 390 #define SPACE   8               /* space if plus */
 391 #define LEFT    16              /* left justified */
 392 #define SMALL   32              /* Must be 32 == 0x20 */
 393 #define SPECIAL 64              /* 0x */
 394
 395 static char *number(char *buf, char *end, unsigned long long num, int base, int size, int precision, int type)
 396 {
 397         /* we are called with base 8, 10 or 16, only, thus don't need "G..."  */
 398         static const char digits[16] = "0123456789ABCDEF"; /* "GHIJKLMNOPQRSTUVWXYZ"; */
 399
 400         char tmp[66];
 401         char sign;
 402         char locase;
 403         int need_pfx = ((type & SPECIAL) && base != 10);
 404         int i;
 405
 406         /* locase = 0 or 0x20. ORing digits or letters with 'locase'
 407          * produces same digits or (maybe lowercased) letters */
 408         locase = (type & SMALL);
 409         if (type & LEFT)
 410                 type &= ~ZEROPAD;
 411         sign = 0;
 412         if (type & SIGN) {
 413                 if ((signed long long) num < 0) {
 414                         sign = '-';
 415                         num = - (signed long long) num;
 416                         size--;
 417                 } else if (type & PLUS) {
 418                         sign = '+';
 419                         size--;
 420                 } else if (type & SPACE) {
 421                         sign = ' ';
 422                         size--;
 423                 }
 424         }
 425         if (need_pfx) {
 426                 size--;
 427                 if (base == 16)
 428                         size--;
 429         }
 430
 431         /* generate full string in tmp[], in reverse order */
 432         i = 0;
 433         if (num == 0)
 434                 tmp[i++] = '0';
 435         /* Generic code, for any base:
 436         else do {
 437                 tmp[i++] = (digits[do_div(num,base)] | locase);
 438         } while (num != 0);
 439         */
 440         else if (base != 10) { /* 8 or 16 */
 441                 int mask = base - 1;
 442                 int shift = 3;
 443                 if (base == 16) shift = 4;
 444                 do {
 445                         tmp[i++] = (digits[((unsigned char)num) & mask] | locase);
 446                         num >>= shift;
 447                 } while (num);
 448         } else { /* base 10 */
 449                 i = put_dec(tmp, num) - tmp;
 450         }
 451
 452         /* printing 100 using %2d gives "100", not "00" */
 453         if (i > precision)
 454                 precision = i;
 455         /* leading space padding */
 456         size -= precision;
 457         if (!(type & (ZEROPAD+LEFT))) {
 458                 while(--size >= 0) {
 459                         if (buf < end)
 460                                 *buf = ' ';
 461                         ++buf;
 462                 }
 463         }
 464         /* sign */
 465         if (sign) {
 466                 if (buf < end)
 467                         *buf = sign;
 468                 ++buf;
 469         }
 470         /* "0x" / "0" prefix */
 471         if (need_pfx) {
 472                 if (buf < end)
 473                         *buf = '0';
 474                 ++buf;
 475                 if (base == 16) {
 476                         if (buf < end)
 477                                 *buf = ('X' | locase);
 478                         ++buf;
 479                 }
 480         }
 481         /* zero or space padding */
 482         if (!(type & LEFT)) {
 483                 char c = (type & ZEROPAD) ? '0' : ' ';
 484                 while (--size >= 0) {
 485                         if (buf < end)
 486                                 *buf = c;
 487                         ++buf;
 488                 }
 489         }
 490         /* hmm even more zero padding? */
 491         while (i <= --precision) {
 492                 if (buf < end)
 493                         *buf = '0';
 494                 ++buf;
 495         }
 496         /* actual digits of result */
 497         while (--i >= 0) {
 498                 if (buf < end)
 499                         *buf = tmp[i];
 500                 ++buf;
 501         }
 502         /* trailing space padding */
 503         while (--size >= 0) {
 504                 if (buf < end)
 505                         *buf = ' ';
 506                 ++buf;
 507         }
 508         return buf;
 509 }
 510
 511 static char *string(char *buf, char *end, char *s, int field_width, int precision, int flags)
 512 {
 513         int len, i;
 514
 515         if ((unsigned long)s < PAGE_SIZE)
 516                 s = "<NULL>";
 517
 518         len = strnlen(s, precision);
 519
 520         if (!(flags & LEFT)) {
 521                 while (len < field_width--) {
 522                         if (buf < end)
 523                                 *buf = ' ';
 524                         ++buf;
 525                 }
 526         }
 527         for (i = 0; i < len; ++i) {
 528                 if (buf < end)
 529                         *buf = *s;
 530                 ++buf; ++s;
 531         }
 532         while (len < field_width--) {
 533                 if (buf < end)
 534                         *buf = ' ';
 535                 ++buf;
 536         }
 537         return buf;
 538 }
 539
 540 static char *symbol_string(char *buf, char *end, void *ptr, int field_width, int precision, int flags)
 541 {
 542         unsigned long value = (unsigned long) ptr;
 543 #ifdef CONFIG_KALLSYMS
 544         char sym[KSYM_SYMBOL_LEN];
 545         sprint_symbol(sym, value);
 546         return string(buf, end, sym, field_width, precision, flags);
 547 #else
 548         field_width = 2*sizeof(void *);
 549         flags |= SPECIAL | SMALL | ZEROPAD;
 550         return number(buf, end, value, 16, field_width, precision, flags);
 551 #endif
 552 }
 553
 554 static char *resource_string(char *buf, char *end, struct resource *res, int field_width, int precision, int flags)
 555 {
 556 #ifndef IO_RSRC_PRINTK_SIZE
 557 #define IO_RSRC_PRINTK_SIZE     4
 558 #endif
 559
 560 #ifndef MEM_RSRC_PRINTK_SIZE
 561 #define MEM_RSRC_PRINTK_SIZE    8
 562 #endif
 563
 564         /* room for the actual numbers, the two "0x", -, [, ] and the final zero */
 565         char sym[4*sizeof(resource_size_t) + 8];
 566         char *p = sym, *pend = sym + sizeof(sym);
 567         int size = -1;
 568
 569         if (res->flags & IORESOURCE_IO)
 570                 size = IO_RSRC_PRINTK_SIZE;
 571         else if (res->flags & IORESOURCE_MEM)
 572                 size = MEM_RSRC_PRINTK_SIZE;
 573
 574         *p++ = '[';
 575         p = number(p, pend, res->start, 16, size, -1, SPECIAL | SMALL | ZEROPAD);
 576         *p++ = '-';
 577         p = number(p, pend, res->end, 16, size, -1, SPECIAL | SMALL | ZEROPAD);
 578         *p++ = ']';
 579         *p = 0;
 580
 581         return string(buf, end, sym, field_width, precision, flags);
 582 }
 583
 584 static char *mac_address_string(char *buf, char *end, u8 *addr, int field_width,
 585                                 int precision, int flags)
 586 {
 587         char mac_addr[6 * 3]; /* (6 * 2 hex digits), 5 colons and trailing zero */
 588         char *p = mac_addr;
 589         int i;
 590
 591         for (i = 0; i < 6; i++) {
 592                 p = pack_hex_byte(p, addr[i]);
 593                 if (!(flags & SPECIAL) && i != 5)
 594                         *p++ = ':';
 595         }
 596         *p = '\0';
 597
 598         return string(buf, end, mac_addr, field_width, precision, flags & ~SPECIAL);
 599 }
 600
 601 static char *ip6_addr_string(char *buf, char *end, u8 *addr, int field_width,
 602                          int precision, int flags)
 603 {
 604         char ip6_addr[8 * 5]; /* (8 * 4 hex digits), 7 colons and trailing zero */
 605         char *p = ip6_addr;
 606         int i;
 607
 608         for (i = 0; i < 8; i++) {
 609                 p = pack_hex_byte(p, addr[2 * i]);
 610                 p = pack_hex_byte(p, addr[2 * i + 1]);
 611                 if (!(flags & SPECIAL) && i != 7)
 612                         *p++ = ':';
 613         }
 614         *p = '\0';
 615
 616         return string(buf, end, ip6_addr, field_width, precision, flags & ~SPECIAL);
 617 }
 618
 619 static char *ip4_addr_string(char *buf, char *end, u8 *addr, int field_width,
 620                          int precision, int flags)
 621 {
 622         char ip4_addr[4 * 4]; /* (4 * 3 decimal digits), 3 dots and trailing zero */
 623         char temp[3];   /* hold each IP quad in reverse order */
 624         char *p = ip4_addr;
 625         int i, digits;
 626
 627         for (i = 0; i < 4; i++) {
 628                 digits = put_dec_trunc(temp, addr[i]) - temp;
 629                 /* reverse the digits in the quad */
 630                 while (digits--)
 631                         *p++ = temp[digits];
 632                 if (i != 3)
 633                         *p++ = '.';
 634         }
 635         *p = '\0';
 636
 637         return string(buf, end, ip4_addr, field_width, precision, flags & ~SPECIAL);
 638 }
 639
 640 /*
 641  * Show a '%p' thing.  A kernel extension is that the '%p' is followed
 642  * by an extra set of alphanumeric characters that are extended format
 643  * specifiers.
 644  *
 645  * Right now we handle:
 646  *
 647  * - 'F' For symbolic function descriptor pointers
 648  * - 'S' For symbolic direct pointers
 649  * - 'R' For a struct resource pointer, it prints the range of
 650  *       addresses (not the name nor the flags)
 651  * - 'M' For a 6-byte MAC address, it prints the address in the
 652  *       usual colon-separated hex notation
 653  * - 'I' [46] for IPv4/IPv6 addresses printed in the usual way (dot-separated
 654  *       decimal for v4 and colon separated network-order 16 bit hex for v6)
 655  * - 'i' [46] for 'raw' IPv4/IPv6 addresses, IPv6 omits the colons, IPv4 is
 656  *       currently the same
 657  *
 658  * Note: The difference between 'S' and 'F' is that on ia64 and ppc64
 659  * function pointers are really function descriptors, which contain a
 660  * pointer to the real address.
 661  */
 662 static char *pointer(const char *fmt, char *buf, char *end, void *ptr, int field_width, int precision, int flags)
 663 {
 664         switch (*fmt) {
 665         case 'F':
 666                 ptr = dereference_function_descriptor(ptr);
 667                 /* Fallthrough */
 668         case 'S':
 669                 return symbol_string(buf, end, ptr, field_width, precision, flags);
 670         case 'R':
 671                 return resource_string(buf, end, ptr, field_width, precision, flags);
 672         case 'M':
 673                 return mac_address_string(buf, end, ptr, field_width, precision, flags);
 674         case 'i':
 675                 flags |= SPECIAL;
 676                 /* Fallthrough */
 677         case 'I':
 678                 if (fmt[1] == '6')
 679                         return ip6_addr_string(buf, end, ptr, field_width, precision, flags);
 680                 if (fmt[1] == '4')
 681                         return ip4_addr_string(buf, end, ptr, field_width, precision, flags);
 682                 flags &= ~SPECIAL;
 683                 break;
 684         }
 685         flags |= SMALL;
 686         if (field_width == -1) {
 687                 field_width = 2*sizeof(void *);
 688                 flags |= ZEROPAD;
 689         }
 690         return number(buf, end, (unsigned long) ptr, 16, field_width, precision, flags);
 691 }
 692
 693 /**
 694  * vsnprintf - Format a string and place it in a buffer
 695  * @buf: The buffer to place the result into
 696  * @size: The size of the buffer, including the trailing null space
 697  * @fmt: The format string to use
 698  * @args: Arguments for the format string
 699  *
 700  * This function follows C99 vsnprintf, but has some extensions:
 701  * %pS output the name of a text symbol
 702  * %pF output the name of a function pointer
 703  * %pR output the address range in a struct resource
 704  *
 705  * The return value is the number of characters which would
 706  * be generated for the given input, excluding the trailing
 707  * '\0', as per ISO C99. If you want to have the exact
 708  * number of characters written into @buf as return value
 709  * (not including the trailing '\0'), use vscnprintf(). If the
 710  * return is greater than or equal to @size, the resulting
 711  * string is truncated.
 712  *
 713  * Call this function if you are already dealing with a va_list.
 714  * You probably want snprintf() instead.
 715  */
 716 int vsnprintf(char *buf, size_t size, const char *fmt, va_list args)
 717 {
 718         unsigned long long num;
 719         int base;
 720         char *str, *end, c;
 721
 722         int flags;              /* flags to number() */
 723
 724         int field_width;        /* width of output field */
 725         int precision;          /* min. # of digits for integers; max
 726                                    number of chars for from string */
 727         int qualifier;          /* 'h', 'l', or 'L' for integer fields */
 728                                 /* 'z' support added 23/7/1999 S.H.    */
 729                                 /* 'z' changed to 'Z' --davidm 1/25/99 */
 730                                 /* 't' added for ptrdiff_t */
 731
 732         /* Reject out-of-range values early.  Large positive sizes are
 733            used for unknown buffer sizes. */
 734         if (unlikely((int) size < 0)) {
 735                 /* There can be only one.. */
 736                 static char warn = 1;
 737                 WARN_ON(warn);
 738                 warn = 0;
 739                 return 0;
 740         }
 741
 742         str = buf;
 743         end = buf + size;
 744
 745         /* Make sure end is always >= buf */
 746         if (end < buf) {
 747                 end = ((void *)-1);
 748                 size = end - buf;
 749         }
 750
 751         for (; *fmt ; ++fmt) {
 752                 if (*fmt != '%') {
 753                         if (str < end)
 754                                 *str = *fmt;
 755                         ++str;
 756                         continue;
 757                 }
 758
 759                 /* process flags */
 760                 flags = 0;
 761                 repeat:
 762                         ++fmt;          /* this also skips first '%' */
 763                         switch (*fmt) {
 764                                 case '-': flags |= LEFT; goto repeat;
 765                                 case '+': flags |= PLUS; goto repeat;
 766                                 case ' ': flags |= SPACE; goto repeat;
 767                                 case '#': flags |= SPECIAL; goto repeat;
 768                                 case '0': flags |= ZEROPAD; goto repeat;
 769                         }
 770
 771                 /* get field width */
 772                 field_width = -1;
 773                 if (isdigit(*fmt))
 774                         field_width = skip_atoi(&fmt);
 775                 else if (*fmt == '*') {
 776                         ++fmt;
 777                         /* it's the next argument */
 778                         field_width = va_arg(args, int);
 779                         if (field_width < 0) {
 780                                 field_width = -field_width;
 781                                 flags |= LEFT;
 782                         }
 783                 }
 784
 785                 /* get the precision */
 786                 precision = -1;
 787                 if (*fmt == '.') {
 788                         ++fmt;
 789                         if (isdigit(*fmt))
 790                                 precision = skip_atoi(&fmt);
 791                         else if (*fmt == '*') {
 792                                 ++fmt;
 793                                 /* it's the next argument */
 794                                 precision = va_arg(args, int);
 795                         }
 796                         if (precision < 0)
 797                                 precision = 0;
 798                 }
 799
 800                 /* get the conversion qualifier */
 801                 qualifier = -1;
 802                 if (*fmt == 'h' || *fmt == 'l' || *fmt == 'L' ||
 803                     *fmt =='Z' || *fmt == 'z' || *fmt == 't') {
 804                         qualifier = *fmt;
 805                         ++fmt;
 806                         if (qualifier == 'l' && *fmt == 'l') {
 807                                 qualifier = 'L';
 808                                 ++fmt;
 809                         }
 810                 }
 811
 812                 /* default base */
 813                 base = 10;
 814
 815                 switch (*fmt) {
 816                         case 'c':
 817                                 if (!(flags & LEFT)) {
 818                                         while (--field_width > 0) {
 819                                                 if (str < end)
 820                                                         *str = ' ';
 821                                                 ++str;
 822                                         }
 823                                 }
 824                                 c = (unsigned char) va_arg(args, int);
 825                                 if (str < end)
 826                                         *str = c;
 827                                 ++str;
 828                                 while (--field_width > 0) {
 829                                         if (str < end)
 830                                                 *str = ' ';
 831                                         ++str;
 832                                 }
 833                                 continue;
 834
 835                         case 's':
 836                                 str = string(str, end, va_arg(args, char *), field_width, precision, flags);
 837                                 continue;
 838
 839                         case 'p':
 840                                 str = pointer(fmt+1, str, end,
 841                                                 va_arg(args, void *),
 842                                                 field_width, precision, flags);
 843                                 /* Skip all alphanumeric pointer suffixes */
 844                                 while (isalnum(fmt[1]))
 845                                         fmt++;
 846                                 continue;
 847
 848                         case 'n':
 849                                 /* FIXME:
 850                                 * What does C99 say about the overflow case here? */
 851                                 if (qualifier == 'l') {
 852                                         long * ip = va_arg(args, long *);
 853                                         *ip = (str - buf);
 854                                 } else if (qualifier == 'Z' || qualifier == 'z') {
 855                                         size_t * ip = va_arg(args, size_t *);
 856                                         *ip = (str - buf);
 857                                 } else {
 858                                         int * ip = va_arg(args, int *);
 859                                         *ip = (str - buf);
 860                                 }
 861                                 continue;
 862
 863                         case '%':
 864                                 if (str < end)
 865                                         *str = '%';
 866                                 ++str;
 867                                 continue;
 868
 869                                 /* integer number formats - set up the flags and "break" */
 870                         case 'o':
 871                                 base = 8;
 872                                 break;
 873
 874                         case 'x':
 875                                 flags |= SMALL;
 876                         case 'X':
 877                                 base = 16;
 878                                 break;
 879
 880                         case 'd':
 881                         case 'i':
 882                                 flags |= SIGN;
 883                         case 'u':
 884                                 break;
 885
 886                         default:
 887                                 if (str < end)
 888                                         *str = '%';
 889                                 ++str;
 890                                 if (*fmt) {
 891                                         if (str < end)
 892                                                 *str = *fmt;
 893                                         ++str;
 894                                 } else {
 895                                         --fmt;
 896                                 }
 897                                 continue;
 898                 }
 899                 if (qualifier == 'L')
 900                         num = va_arg(args, long long);
 901                 else if (qualifier == 'l') {
 902                         num = va_arg(args, unsigned long);
 903                         if (flags & SIGN)
 904                                 num = (signed long) num;
 905                 } else if (qualifier == 'Z' || qualifier == 'z') {
 906                         num = va_arg(args, size_t);
 907                 } else if (qualifier == 't') {
 908                         num = va_arg(args, ptrdiff_t);
 909                 } else if (qualifier == 'h') {
 910                         num = (unsigned short) va_arg(args, int);
 911                         if (flags & SIGN)
 912                                 num = (signed short) num;
 913                 } else {
 914                         num = va_arg(args, unsigned int);
 915                         if (flags & SIGN)
 916                                 num = (signed int) num;
 917                 }
 918                 str = number(str, end, num, base,
 919                                 field_width, precision, flags);
 920         }
 921         if (size > 0) {
 922                 if (str < end)
 923                         *str = '\0';
 924                 else
 925                         end[-1] = '\0';
 926         }
 927         /* the trailing null byte doesn't count towards the total */
 928         return str-buf;
 929 }
 930 EXPORT_SYMBOL(vsnprintf);
 931
 932 /**
 933  * vscnprintf - Format a string and place it in a buffer
 934  * @buf: The buffer to place the result into
 935  * @size: The size of the buffer, including the trailing null space
 936  * @fmt: The format string to use
 937  * @args: Arguments for the format string
 938  *
 939  * The return value is the number of characters which have been written into
 940  * the @buf not including the trailing '\0'. If @size is <= 0 the function
 941  * returns 0.
 942  *
 943  * Call this function if you are already dealing with a va_list.
 944  * You probably want scnprintf() instead.
 945  *
 946  * See the vsnprintf() documentation for format string extensions over C99.
 947  */
 948 int vscnprintf(char *buf, size_t size, const char *fmt, va_list args)
 949 {
 950         int i;
 951
 952         i=vsnprintf(buf,size,fmt,args);
 953         return (i >= size) ? (size - 1) : i;
 954 }
 955 EXPORT_SYMBOL(vscnprintf);
 956
 957 /**
 958  * snprintf - Format a string and place it in a buffer
 959  * @buf: The buffer to place the result into
 960  * @size: The size of the buffer, including the trailing null space
 961  * @fmt: The format string to use
 962  * @...: Arguments for the format string
 963  *
 964  * The return value is the number of characters which would be
 965  * generated for the given input, excluding the trailing null,
 966  * as per ISO C99.  If the return is greater than or equal to
 967  * @size, the resulting string is truncated.
 968  *
 969  * See the vsnprintf() documentation for format string extensions over C99.
 970  */
 971 int snprintf(char * buf, size_t size, const char *fmt, ...)
 972 {
 973         va_list args;
 974         int i;
 975
 976         va_start(args, fmt);
 977         i=vsnprintf(buf,size,fmt,args);
 978         va_end(args);
 979         return i;
 980 }
 981 EXPORT_SYMBOL(snprintf);
 982
 983 /**
 984  * scnprintf - Format a string and place it in a buffer
 985  * @buf: The buffer to place the result into
 986  * @size: The size of the buffer, including the trailing null space
 987  * @fmt: The format string to use
 988  * @...: Arguments for the format string
 989  *
 990  * The return value is the number of characters written into @buf not including
 991  * the trailing '\0'. If @size is <= 0 the function returns 0.
 992  */
 993
 994 int scnprintf(char * buf, size_t size, const char *fmt, ...)
 995 {
 996         va_list args;
 997         int i;
 998
 999         va_start(args, fmt);
1000         i = vsnprintf(buf, size, fmt, args);
1001         va_end(args);
1002         return (i >= size) ? (size - 1) : i;
1003 }
1004 EXPORT_SYMBOL(scnprintf);
1005
1006 /**
1007  * vsprintf - Format a string and place it in a buffer
1008  * @buf: The buffer to place the result into
1009  * @fmt: The format string to use
1010  * @args: Arguments for the format string
1011  *
1012  * The function returns the number of characters written
1013  * into @buf. Use vsnprintf() or vscnprintf() in order to avoid
1014  * buffer overflows.
1015  *
1016  * Call this function if you are already dealing with a va_list.
1017  * You probably want sprintf() instead.
1018  *
1019  * See the vsnprintf() documentation for format string extensions over C99.
1020  */
1021 int vsprintf(char *buf, const char *fmt, va_list args)
1022 {
1023         return vsnprintf(buf, INT_MAX, fmt, args);
1024 }
1025 EXPORT_SYMBOL(vsprintf);
1026
1027 /**
1028  * sprintf - Format a string and place it in a buffer
1029  * @buf: The buffer to place the result into
1030  * @fmt: The format string to use
1031  * @...: Arguments for the format string
1032  *
1033  * The function returns the number of characters written
1034  * into @buf. Use snprintf() or scnprintf() in order to avoid
1035  * buffer overflows.
1036  *
1037  * See the vsnprintf() documentation for format string extensions over C99.
1038  */
1039 int sprintf(char * buf, const char *fmt, ...)
1040 {
1041         va_list args;
1042         int i;
1043
1044         va_start(args, fmt);
1045         i=vsnprintf(buf, INT_MAX, fmt, args);
1046         va_end(args);
1047         return i;
1048 }
1049 EXPORT_SYMBOL(sprintf);
1050
1051 /**
1052  * vsscanf - Unformat a buffer into a list of arguments
1053  * @buf:        input buffer
1054  * @fmt:        format of buffer
1055  * @args:       arguments
1056  */
1057 int vsscanf(const char * buf, const char * fmt, va_list args)
1058 {
1059         const char *str = buf;
1060         char *next;
1061         char digit;
1062         int num = 0;
1063         int qualifier;
1064         int base;
1065         int field_width;
1066         int is_sign = 0;
1067
1068         while(*fmt && *str) {
1069                 /* skip any white space in format */
1070                 /* white space in format matchs any amount of
1071                  * white space, including none, in the input.
1072                  */
1073                 if (isspace(*fmt)) {
1074                         while (isspace(*fmt))
1075                                 ++fmt;
1076                         while (isspace(*str))
1077                                 ++str;
1078                 }
1079
1080                 /* anything that is not a conversion must match exactly */
1081                 if (*fmt != '%' && *fmt) {
1082                         if (*fmt++ != *str++)
1083                                 break;
1084                         continue;
1085                 }
1086
1087                 if (!*fmt)
1088                         break;
1089                 ++fmt;
1090
1091                 /* skip this conversion.
1092                  * advance both strings to next white space
1093                  */
1094                 if (*fmt == '*') {
1095                         while (!isspace(*fmt) && *fmt)
1096                                 fmt++;
1097                         while (!isspace(*str) && *str)
1098                                 str++;
1099                         continue;
1100                 }
1101
1102                 /* get field width */
1103                 field_width = -1;
1104                 if (isdigit(*fmt))
1105                         field_width = skip_atoi(&fmt);
1106
1107                 /* get conversion qualifier */
1108                 qualifier = -1;
1109                 if (*fmt == 'h' || *fmt == 'l' || *fmt == 'L' ||
1110                     *fmt == 'Z' || *fmt == 'z') {
1111                         qualifier = *fmt++;
1112                         if (unlikely(qualifier == *fmt)) {
1113                                 if (qualifier == 'h') {
1114                                         qualifier = 'H';
1115                                         fmt++;
1116                                 } else if (qualifier == 'l') {
1117                                         qualifier = 'L';
1118                                         fmt++;
1119                                 }
1120                         }
1121                 }
1122                 base = 10;
1123                 is_sign = 0;
1124
1125                 if (!*fmt || !*str)
1126                         break;
1127
1128                 switch(*fmt++) {
1129                 case 'c':
1130                 {
1131                         char *s = (char *) va_arg(args,char*);
1132                         if (field_width == -1)
1133                                 field_width = 1;
1134                         do {
1135                                 *s++ = *str++;
1136                         } while (--field_width > 0 && *str);
1137                         num++;
1138                 }
1139                 continue;
1140                 case 's':
1141                 {
1142                         char *s = (char *) va_arg(args, char *);
1143                         if(field_width == -1)
1144                                 field_width = INT_MAX;
1145                         /* first, skip leading white space in buffer */
1146                         while (isspace(*str))
1147                                 str++;
1148
1149                         /* now copy until next white space */
1150                         while (*str && !isspace(*str) && field_width--) {
1151                                 *s++ = *str++;
1152                         }
1153                         *s = '\0';
1154                         num++;
1155                 }
1156                 continue;
1157                 case 'n':
1158                         /* return number of characters read so far */
1159                 {
1160                         int *i = (int *)va_arg(args,int*);
1161                         *i = str - buf;
1162                 }
1163                 continue;
1164                 case 'o':
1165                         base = 8;
1166                         break;
1167                 case 'x':
1168                 case 'X':
1169                         base = 16;
1170                         break;
1171                 case 'i':
1172                         base = 0;
1173                 case 'd':
1174                         is_sign = 1;
1175                 case 'u':
1176                         break;
1177                 case '%':
1178                         /* looking for '%' in str */
1179                         if (*str++ != '%')
1180                                 return num;
1181                         continue;
1182                 default:
1183                         /* invalid format; stop here */
1184                         return num;
1185                 }
1186
1187                 /* have some sort of integer conversion.
1188                  * first, skip white space in buffer.
1189                  */
1190                 while (isspace(*str))
1191                         str++;
1192
1193                 digit = *str;
1194                 if (is_sign && digit == '-')
1195                         digit = *(str + 1);
1196
1197                 if (!digit
1198                     || (base == 16 && !isxdigit(digit))
1199                     || (base == 10 && !isdigit(digit))
1200                     || (base == 8 && (!isdigit(digit) || digit > '7'))
1201                     || (base == 0 && !isdigit(digit)))
1202                                 break;
1203
1204                 switch(qualifier) {
1205                 case 'H':       /* that's 'hh' in format */
1206                         if (is_sign) {
1207                                 signed char *s = (signed char *) va_arg(args,signed char *);
1208                                 *s = (signed char) simple_strtol(str,&next,base);
1209                         } else {
1210                                 unsigned char *s = (unsigned char *) va_arg(args, unsigned char *);
1211                                 *s = (unsigned char) simple_strtoul(str, &next, base);
1212                         }
1213                         break;
1214                 case 'h':
1215                         if (is_sign) {
1216                                 short *s = (short *) va_arg(args,short *);
1217                                 *s = (short) simple_strtol(str,&next,base);
1218                         } else {
1219                                 unsigned short *s = (unsigned short *) va_arg(args, unsigned short *);
1220                                 *s = (unsigned short) simple_strtoul(str, &next, base);
1221                         }
1222                         break;
1223                 case 'l':
1224                         if (is_sign) {
1225                                 long *l = (long *) va_arg(args,long *);
1226                                 *l = simple_strtol(str,&next,base);
1227                         } else {
1228                                 unsigned long *l = (unsigned long*) va_arg(args,unsigned long*);
1229                                 *l = simple_strtoul(str,&next,base);
1230                         }
1231                         break;
1232                 case 'L':
1233                         if (is_sign) {
1234                                 long long *l = (long long*) va_arg(args,long long *);
1235                                 *l = simple_strtoll(str,&next,base);
1236                         } else {
1237                                 unsigned long long *l = (unsigned long long*) va_arg(args,unsigned long long*);
1238                                 *l = simple_strtoull(str,&next,base);
1239                         }
1240                         break;
1241                 case 'Z':
1242                 case 'z':
1243                 {
1244                         size_t *s = (size_t*) va_arg(args,size_t*);
1245                         *s = (size_t) simple_strtoul(str,&next,base);
1246                 }
1247                 break;
1248                 default:
1249                         if (is_sign) {
1250                                 int *i = (int *) va_arg(args, int*);
1251                                 *i = (int) simple_strtol(str,&next,base);
1252                         } else {
1253                                 unsigned int *i = (unsigned int*) va_arg(args, unsigned int*);
1254                                 *i = (unsigned int) simple_strtoul(str,&next,base);
1255                         }
1256                         break;
1257                 }
1258                 num++;
1259
1260                 if (!next)
1261                         break;
1262                 str = next;
1263         }
1264
1265         /*
1266          * Now we've come all the way through so either the input string or the
1267          * format ended. In the former case, there can be a %n at the current
1268          * position in the format that needs to be filled.
1269          */
1270         if (*fmt == '%' && *(fmt + 1) == 'n') {
1271                 int *p = (int *)va_arg(args, int *);
1272                 *p = str - buf;
1273         }
1274
1275         return num;
1276 }
1277 EXPORT_SYMBOL(vsscanf);
1278
1279 /**
1280  * sscanf - Unformat a buffer into a list of arguments
1281  * @buf:        input buffer
1282  * @fmt:        formatting of buffer
1283  * @...:        resulting arguments
1284  */
1285 int sscanf(const char * buf, const char * fmt, ...)
1286 {
1287         va_list args;
1288         int i;
1289
1290         va_start(args,fmt);
1291         i = vsscanf(buf,fmt,args);
1292         va_end(args);
1293         return i;
1294 }
1295 EXPORT_SYMBOL(sscanf);