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 #include <stdarg.h>
  13 #include <linux/types.h>
  14 #include <linux/string.h>
  15 #include <linux/ctype.h>
  16 #include <errno.h>
  17
  18 #include <common.h>
  19 #if !defined (CONFIG_PANIC_HANG)
  20 #include <command.h>
  21 #endif
  22
  23 #include <div64.h>
  24 # define NUM_TYPE long long
  25 #define noinline __attribute__((noinline))
  26
  27 const char hex_asc[] = "0123456789abcdef";
  28 #define hex_asc_lo(x)   hex_asc[((x) & 0x0f)]
  29 #define hex_asc_hi(x)   hex_asc[((x) & 0xf0) >> 4]
  30
  31 static inline char *pack_hex_byte(char *buf, u8 byte)
  32 {
  33         *buf++ = hex_asc_hi(byte);
  34         *buf++ = hex_asc_lo(byte);
  35         return buf;
  36 }
  37
  38 unsigned long simple_strtoul(const char *cp,char **endp,unsigned int base)
  39 {
  40         unsigned long result = 0,value;
  41
  42         if (*cp == '0') {
  43                 cp++;
  44                 if ((*cp == 'x') && isxdigit(cp[1])) {
  45                         base = 16;
  46                         cp++;
  47                 }
  48                 if (!base) {
  49                         base = 8;
  50                 }
  51         }
  52         if (!base) {
  53                 base = 10;
  54         }
  55         while (isxdigit(*cp) && (value = isdigit(*cp) ? *cp-'0' : (islower(*cp)
  56             ? toupper(*cp) : *cp)-'A'+10) < base) {
  57                 result = result*base + value;
  58                 cp++;
  59         }
  60         if (endp)
  61                 *endp = (char *)cp;
  62         return result;
  63 }
  64
  65 /**
  66  * strict_strtoul - convert a string to an unsigned long strictly
  67  * @cp: The string to be converted
  68  * @base: The number base to use
  69  * @res: The converted result value
  70  *
  71  * strict_strtoul converts a string to an unsigned long only if the
  72  * string is really an unsigned long string, any string containing
  73  * any invalid char at the tail will be rejected and -EINVAL is returned,
  74  * only a newline char at the tail is acceptible because people generally
  75  * change a module parameter in the following way:
  76  *
  77  *      echo 1024 > /sys/module/e1000/parameters/copybreak
  78  *
  79  * echo will append a newline to the tail.
  80  *
  81  * It returns 0 if conversion is successful and *res is set to the converted
  82  * value, otherwise it returns -EINVAL and *res is set to 0.
  83  *
  84  * simple_strtoul just ignores the successive invalid characters and
  85  * return the converted value of prefix part of the string.
  86  *
  87  * Copied this function from Linux 2.6.38 commit ID:
  88  * 521cb40b0c44418a4fd36dc633f575813d59a43d
  89  *
  90  */
  91 int strict_strtoul(const char *cp, unsigned int base, unsigned long *res)
  92 {
  93         char *tail;
  94         unsigned long val;
  95         size_t len;
  96
  97         *res = 0;
  98         len = strlen(cp);
  99         if (len == 0)
 100                 return -EINVAL;
 101
 102         val = simple_strtoul(cp, &tail, base);
 103         if (tail == cp)
 104                 return -EINVAL;
 105
 106         if ((*tail == '\0') ||
 107                 ((len == (size_t)(tail - cp) + 1) && (*tail == '\n'))) {
 108                 *res = val;
 109                 return 0;
 110         }
 111
 112         return -EINVAL;
 113 }
 114
 115 long simple_strtol(const char *cp,char **endp,unsigned int base)
 116 {
 117         if(*cp=='-')
 118                 return -simple_strtoul(cp+1,endp,base);
 119         return simple_strtoul(cp,endp,base);
 120 }
 121
 122 int ustrtoul(const char *cp, char **endp, unsigned int base)
 123 {
 124         unsigned long result = simple_strtoul(cp, endp, base);
 125         switch (**endp) {
 126         case 'G' :
 127                 result *= 1024;
 128                 /* fall through */
 129         case 'M':
 130                 result *= 1024;
 131                 /* fall through */
 132         case 'K':
 133         case 'k':
 134                 result *= 1024;
 135                 if ((*endp)[1] == 'i') {
 136                         if ((*endp)[2] == 'B')
 137                                 (*endp) += 3;
 138                         else
 139                                 (*endp) += 2;
 140                 }
 141         }
 142         return result;
 143 }
 144
 145 unsigned long long simple_strtoull (const char *cp, char **endp, unsigned int base)
 146 {
 147         unsigned long long result = 0, value;
 148
 149         if (*cp == '0') {
 150                 cp++;
 151                 if ((*cp == 'x') && isxdigit (cp[1])) {
 152                         base = 16;
 153                         cp++;
 154                 }
 155                 if (!base) {
 156                         base = 8;
 157                 }
 158         }
 159         if (!base) {
 160                 base = 10;
 161         }
 162         while (isxdigit (*cp) && (value = isdigit (*cp)
 163                                 ? *cp - '0'
 164                                 : (islower (*cp) ? toupper (*cp) : *cp) - 'A' + 10) < base) {
 165                 result = result * base + value;
 166                 cp++;
 167         }
 168         if (endp)
 169                 *endp = (char *) cp;
 170         return result;
 171 }
 172
 173 /* we use this so that we can do without the ctype library */
 174 #define is_digit(c)     ((c) >= '0' && (c) <= '9')
 175
 176 static int skip_atoi(const char **s)
 177 {
 178         int i=0;
 179
 180         while (is_digit(**s))
 181                 i = i*10 + *((*s)++) - '0';
 182         return i;
 183 }
 184
 185 /* Decimal conversion is by far the most typical, and is used
 186  * for /proc and /sys data. This directly impacts e.g. top performance
 187  * with many processes running. We optimize it for speed
 188  * using code from
 189  * http://www.cs.uiowa.edu/~jones/bcd/decimal.html
 190  * (with permission from the author, Douglas W. Jones). */
 191
 192 /* Formats correctly any integer in [0,99999].
 193  * Outputs from one to five digits depending on input.
 194  * On i386 gcc 4.1.2 -O2: ~250 bytes of code. */
 195 static char* put_dec_trunc(char *buf, unsigned q)
 196 {
 197         unsigned d3, d2, d1, d0;
 198         d1 = (q>>4) & 0xf;
 199         d2 = (q>>8) & 0xf;
 200         d3 = (q>>12);
 201
 202         d0 = 6*(d3 + d2 + d1) + (q & 0xf);
 203         q = (d0 * 0xcd) >> 11;
 204         d0 = d0 - 10*q;
 205         *buf++ = d0 + '0'; /* least significant digit */
 206         d1 = q + 9*d3 + 5*d2 + d1;
 207         if (d1 != 0) {
 208                 q = (d1 * 0xcd) >> 11;
 209                 d1 = d1 - 10*q;
 210                 *buf++ = d1 + '0'; /* next digit */
 211
 212                 d2 = q + 2*d2;
 213                 if ((d2 != 0) || (d3 != 0)) {
 214                         q = (d2 * 0xd) >> 7;
 215                         d2 = d2 - 10*q;
 216                         *buf++ = d2 + '0'; /* next digit */
 217
 218                         d3 = q + 4*d3;
 219                         if (d3 != 0) {
 220                                 q = (d3 * 0xcd) >> 11;
 221                                 d3 = d3 - 10*q;
 222                                 *buf++ = d3 + '0';  /* next digit */
 223                                 if (q != 0)
 224                                         *buf++ = q + '0';  /* most sign. digit */
 225                         }
 226                 }
 227         }
 228         return buf;
 229 }
 230 /* Same with if's removed. Always emits five digits */
 231 static char* put_dec_full(char *buf, unsigned q)
 232 {
 233         /* BTW, if q is in [0,9999], 8-bit ints will be enough, */
 234         /* but anyway, gcc produces better code with full-sized ints */
 235         unsigned d3, d2, d1, d0;
 236         d1 = (q>>4) & 0xf;
 237         d2 = (q>>8) & 0xf;
 238         d3 = (q>>12);
 239
 240         /*
 241          * Possible ways to approx. divide by 10
 242          * gcc -O2 replaces multiply with shifts and adds
 243          * (x * 0xcd) >> 11: 11001101 - shorter code than * 0x67 (on i386)
 244          * (x * 0x67) >> 10:  1100111
 245          * (x * 0x34) >> 9:    110100 - same
 246          * (x * 0x1a) >> 8:     11010 - same
 247          * (x * 0x0d) >> 7:      1101 - same, shortest code (on i386)
 248          */
 249
 250         d0 = 6*(d3 + d2 + d1) + (q & 0xf);
 251         q = (d0 * 0xcd) >> 11;
 252         d0 = d0 - 10*q;
 253         *buf++ = d0 + '0';
 254         d1 = q + 9*d3 + 5*d2 + d1;
 255                 q = (d1 * 0xcd) >> 11;
 256                 d1 = d1 - 10*q;
 257                 *buf++ = d1 + '0';
 258
 259                 d2 = q + 2*d2;
 260                         q = (d2 * 0xd) >> 7;
 261                         d2 = d2 - 10*q;
 262                         *buf++ = d2 + '0';
 263
 264                         d3 = q + 4*d3;
 265                                 q = (d3 * 0xcd) >> 11; /* - shorter code */
 266                                 /* q = (d3 * 0x67) >> 10; - would also work */
 267                                 d3 = d3 - 10*q;
 268                                 *buf++ = d3 + '0';
 269                                         *buf++ = q + '0';
 270         return buf;
 271 }
 272 /* No inlining helps gcc to use registers better */
 273 static noinline char* put_dec(char *buf, unsigned NUM_TYPE num)
 274 {
 275         while (1) {
 276                 unsigned rem;
 277                 if (num < 100000)
 278                         return put_dec_trunc(buf, num);
 279                 rem = do_div(num, 100000);
 280                 buf = put_dec_full(buf, rem);
 281         }
 282 }
 283
 284 #define ZEROPAD 1               /* pad with zero */
 285 #define SIGN    2               /* unsigned/signed long */
 286 #define PLUS    4               /* show plus */
 287 #define SPACE   8               /* space if plus */
 288 #define LEFT    16              /* left justified */
 289 #define SMALL   32              /* Must be 32 == 0x20 */
 290 #define SPECIAL 64              /* 0x */
 291
 292 static char *number(char *buf, unsigned NUM_TYPE num, int base, int size, int precision, int type)
 293 {
 294         /* we are called with base 8, 10 or 16, only, thus don't need "G..."  */
 295         static const char digits[16] = "0123456789ABCDEF"; /* "GHIJKLMNOPQRSTUVWXYZ"; */
 296
 297         char tmp[66];
 298         char sign;
 299         char locase;
 300         int need_pfx = ((type & SPECIAL) && base != 10);
 301         int i;
 302
 303         /* locase = 0 or 0x20. ORing digits or letters with 'locase'
 304          * produces same digits or (maybe lowercased) letters */
 305         locase = (type & SMALL);
 306         if (type & LEFT)
 307                 type &= ~ZEROPAD;
 308         sign = 0;
 309         if (type & SIGN) {
 310                 if ((signed NUM_TYPE) num < 0) {
 311                         sign = '-';
 312                         num = - (signed NUM_TYPE) num;
 313                         size--;
 314                 } else if (type & PLUS) {
 315                         sign = '+';
 316                         size--;
 317                 } else if (type & SPACE) {
 318                         sign = ' ';
 319                         size--;
 320                 }
 321         }
 322         if (need_pfx) {
 323                 size--;
 324                 if (base == 16)
 325                         size--;
 326         }
 327
 328         /* generate full string in tmp[], in reverse order */
 329         i = 0;
 330         if (num == 0)
 331                 tmp[i++] = '0';
 332         /* Generic code, for any base:
 333         else do {
 334                 tmp[i++] = (digits[do_div(num,base)] | locase);
 335         } while (num != 0);
 336         */
 337         else if (base != 10) { /* 8 or 16 */
 338                 int mask = base - 1;
 339                 int shift = 3;
 340                 if (base == 16) shift = 4;
 341                 do {
 342                         tmp[i++] = (digits[((unsigned char)num) & mask] | locase);
 343                         num >>= shift;
 344                 } while (num);
 345         } else { /* base 10 */
 346                 i = put_dec(tmp, num) - tmp;
 347         }
 348
 349         /* printing 100 using %2d gives "100", not "00" */
 350         if (i > precision)
 351                 precision = i;
 352         /* leading space padding */
 353         size -= precision;
 354         if (!(type & (ZEROPAD+LEFT)))
 355                 while(--size >= 0)
 356                         *buf++ = ' ';
 357         /* sign */
 358         if (sign)
 359                 *buf++ = sign;
 360         /* "0x" / "0" prefix */
 361         if (need_pfx) {
 362                 *buf++ = '0';
 363                 if (base == 16)
 364                         *buf++ = ('X' | locase);
 365         }
 366         /* zero or space padding */
 367         if (!(type & LEFT)) {
 368                 char c = (type & ZEROPAD) ? '0' : ' ';
 369                 while (--size >= 0)
 370                         *buf++ = c;
 371         }
 372         /* hmm even more zero padding? */
 373         while (i <= --precision)
 374                 *buf++ = '0';
 375         /* actual digits of result */
 376         while (--i >= 0)
 377                 *buf++ = tmp[i];
 378         /* trailing space padding */
 379         while (--size >= 0)
 380                 *buf++ = ' ';
 381         return buf;
 382 }
 383
 384 static char *string(char *buf, char *s, int field_width, int precision, int flags)
 385 {
 386         int len, i;
 387
 388         if (s == 0)
 389                 s = "<NULL>";
 390
 391         len = strnlen(s, precision);
 392
 393         if (!(flags & LEFT))
 394                 while (len < field_width--)
 395                         *buf++ = ' ';
 396         for (i = 0; i < len; ++i)
 397                 *buf++ = *s++;
 398         while (len < field_width--)
 399                 *buf++ = ' ';
 400         return buf;
 401 }
 402
 403 #ifdef CONFIG_CMD_NET
 404 static char *mac_address_string(char *buf, u8 *addr, int field_width,
 405                                 int precision, int flags)
 406 {
 407         char mac_addr[6 * 3]; /* (6 * 2 hex digits), 5 colons and trailing zero */
 408         char *p = mac_addr;
 409         int i;
 410
 411         for (i = 0; i < 6; i++) {
 412                 p = pack_hex_byte(p, addr[i]);
 413                 if (!(flags & SPECIAL) && i != 5)
 414                         *p++ = ':';
 415         }
 416         *p = '\0';
 417
 418         return string(buf, mac_addr, field_width, precision, flags & ~SPECIAL);
 419 }
 420
 421 static char *ip6_addr_string(char *buf, u8 *addr, int field_width,
 422                          int precision, int flags)
 423 {
 424         char ip6_addr[8 * 5]; /* (8 * 4 hex digits), 7 colons and trailing zero */
 425         char *p = ip6_addr;
 426         int i;
 427
 428         for (i = 0; i < 8; i++) {
 429                 p = pack_hex_byte(p, addr[2 * i]);
 430                 p = pack_hex_byte(p, addr[2 * i + 1]);
 431                 if (!(flags & SPECIAL) && i != 7)
 432                         *p++ = ':';
 433         }
 434         *p = '\0';
 435
 436         return string(buf, ip6_addr, field_width, precision, flags & ~SPECIAL);
 437 }
 438
 439 static char *ip4_addr_string(char *buf, u8 *addr, int field_width,
 440                          int precision, int flags)
 441 {
 442         char ip4_addr[4 * 4]; /* (4 * 3 decimal digits), 3 dots and trailing zero */
 443         char temp[3];   /* hold each IP quad in reverse order */
 444         char *p = ip4_addr;
 445         int i, digits;
 446
 447         for (i = 0; i < 4; i++) {
 448                 digits = put_dec_trunc(temp, addr[i]) - temp;
 449                 /* reverse the digits in the quad */
 450                 while (digits--)
 451                         *p++ = temp[digits];
 452                 if (i != 3)
 453                         *p++ = '.';
 454         }
 455         *p = '\0';
 456
 457         return string(buf, ip4_addr, field_width, precision, flags & ~SPECIAL);
 458 }
 459 #endif
 460
 461 /*
 462  * Show a '%p' thing.  A kernel extension is that the '%p' is followed
 463  * by an extra set of alphanumeric characters that are extended format
 464  * specifiers.
 465  *
 466  * Right now we handle:
 467  *
 468  * - 'M' For a 6-byte MAC address, it prints the address in the
 469  *       usual colon-separated hex notation
 470  * - 'I' [46] for IPv4/IPv6 addresses printed in the usual way (dot-separated
 471  *       decimal for v4 and colon separated network-order 16 bit hex for v6)
 472  * - 'i' [46] for 'raw' IPv4/IPv6 addresses, IPv6 omits the colons, IPv4 is
 473  *       currently the same
 474  *
 475  * Note: The difference between 'S' and 'F' is that on ia64 and ppc64
 476  * function pointers are really function descriptors, which contain a
 477  * pointer to the real address.
 478  */
 479 static char *pointer(const char *fmt, char *buf, void *ptr, int field_width, int precision, int flags)
 480 {
 481         if (!ptr)
 482                 return string(buf, "(null)", field_width, precision, flags);
 483
 484 #ifdef CONFIG_CMD_NET
 485         switch (*fmt) {
 486         case 'm':
 487                 flags |= SPECIAL;
 488                 /* Fallthrough */
 489         case 'M':
 490                 return mac_address_string(buf, ptr, field_width, precision, flags);
 491         case 'i':
 492                 flags |= SPECIAL;
 493                 /* Fallthrough */
 494         case 'I':
 495                 if (fmt[1] == '6')
 496                         return ip6_addr_string(buf, ptr, field_width, precision, flags);
 497                 if (fmt[1] == '4')
 498                         return ip4_addr_string(buf, ptr, field_width, precision, flags);
 499                 flags &= ~SPECIAL;
 500                 break;
 501         }
 502 #endif
 503         flags |= SMALL;
 504         if (field_width == -1) {
 505                 field_width = 2*sizeof(void *);
 506                 flags |= ZEROPAD;
 507         }
 508         return number(buf, (unsigned long) ptr, 16, field_width, precision, flags);
 509 }
 510
 511 /**
 512  * vsprintf - Format a string and place it in a buffer
 513  * @buf: The buffer to place the result into
 514  * @fmt: The format string to use
 515  * @args: Arguments for the format string
 516  *
 517  * This function follows C99 vsprintf, but has some extensions:
 518  * %pS output the name of a text symbol
 519  * %pF output the name of a function pointer
 520  * %pR output the address range in a struct resource
 521  *
 522  * The function returns the number of characters written
 523  * into @buf.
 524  *
 525  * Call this function if you are already dealing with a va_list.
 526  * You probably want sprintf() instead.
 527  */
 528 int vsprintf(char *buf, const char *fmt, va_list args)
 529 {
 530         unsigned NUM_TYPE num;
 531         int base;
 532         char *str;
 533
 534         int flags;              /* flags to number() */
 535
 536         int field_width;        /* width of output field */
 537         int precision;          /* min. # of digits for integers; max
 538                                    number of chars for from string */
 539         int qualifier;          /* 'h', 'l', or 'L' for integer fields */
 540                                 /* 'z' support added 23/7/1999 S.H.    */
 541                                 /* 'z' changed to 'Z' --davidm 1/25/99 */
 542                                 /* 't' added for ptrdiff_t */
 543
 544         str = buf;
 545
 546         for (; *fmt ; ++fmt) {
 547                 if (*fmt != '%') {
 548                         *str++ = *fmt;
 549                         continue;
 550                 }
 551
 552                 /* process flags */
 553                 flags = 0;
 554                 repeat:
 555                         ++fmt;          /* this also skips first '%' */
 556                         switch (*fmt) {
 557                                 case '-': flags |= LEFT; goto repeat;
 558                                 case '+': flags |= PLUS; goto repeat;
 559                                 case ' ': flags |= SPACE; goto repeat;
 560                                 case '#': flags |= SPECIAL; goto repeat;
 561                                 case '0': flags |= ZEROPAD; goto repeat;
 562                         }
 563
 564                 /* get field width */
 565                 field_width = -1;
 566                 if (is_digit(*fmt))
 567                         field_width = skip_atoi(&fmt);
 568                 else if (*fmt == '*') {
 569                         ++fmt;
 570                         /* it's the next argument */
 571                         field_width = va_arg(args, int);
 572                         if (field_width < 0) {
 573                                 field_width = -field_width;
 574                                 flags |= LEFT;
 575                         }
 576                 }
 577
 578                 /* get the precision */
 579                 precision = -1;
 580                 if (*fmt == '.') {
 581                         ++fmt;
 582                         if (is_digit(*fmt))
 583                                 precision = skip_atoi(&fmt);
 584                         else if (*fmt == '*') {
 585                                 ++fmt;
 586                                 /* it's the next argument */
 587                                 precision = va_arg(args, int);
 588                         }
 589                         if (precision < 0)
 590                                 precision = 0;
 591                 }
 592
 593                 /* get the conversion qualifier */
 594                 qualifier = -1;
 595                 if (*fmt == 'h' || *fmt == 'l' || *fmt == 'L' ||
 596                     *fmt == 'Z' || *fmt == 'z' || *fmt == 't') {
 597                         qualifier = *fmt;
 598                         ++fmt;
 599                         if (qualifier == 'l' && *fmt == 'l') {
 600                                 qualifier = 'L';
 601                                 ++fmt;
 602                         }
 603                 }
 604
 605                 /* default base */
 606                 base = 10;
 607
 608                 switch (*fmt) {
 609                 case 'c':
 610                         if (!(flags & LEFT))
 611                                 while (--field_width > 0)
 612                                         *str++ = ' ';
 613                         *str++ = (unsigned char) va_arg(args, int);
 614                         while (--field_width > 0)
 615                                 *str++ = ' ';
 616                         continue;
 617
 618                 case 's':
 619                         str = string(str, va_arg(args, char *), field_width, precision, flags);
 620                         continue;
 621
 622                 case 'p':
 623                         str = pointer(fmt+1, str,
 624                                         va_arg(args, void *),
 625                                         field_width, precision, flags);
 626                         /* Skip all alphanumeric pointer suffixes */
 627                         while (isalnum(fmt[1]))
 628                                 fmt++;
 629                         continue;
 630
 631                 case 'n':
 632                         if (qualifier == 'l') {
 633                                 long * ip = va_arg(args, long *);
 634                                 *ip = (str - buf);
 635                         } else {
 636                                 int * ip = va_arg(args, int *);
 637                                 *ip = (str - buf);
 638                         }
 639                         continue;
 640
 641                 case '%':
 642                         *str++ = '%';
 643                         continue;
 644
 645                 /* integer number formats - set up the flags and "break" */
 646                 case 'o':
 647                         base = 8;
 648                         break;
 649
 650                 case 'x':
 651                         flags |= SMALL;
 652                 case 'X':
 653                         base = 16;
 654                         break;
 655
 656                 case 'd':
 657                 case 'i':
 658                         flags |= SIGN;
 659                 case 'u':
 660                         break;
 661
 662                 default:
 663                         *str++ = '%';
 664                         if (*fmt)
 665                                 *str++ = *fmt;
 666                         else
 667                                 --fmt;
 668                         continue;
 669                 }
 670                 if (qualifier == 'L')  /* "quad" for 64 bit variables */
 671                         num = va_arg(args, unsigned long long);
 672                 else if (qualifier == 'l') {
 673                         num = va_arg(args, unsigned long);
 674                         if (flags & SIGN)
 675                                 num = (signed long) num;
 676                 } else if (qualifier == 'Z' || qualifier == 'z') {
 677                         num = va_arg(args, size_t);
 678                 } else if (qualifier == 't') {
 679                         num = va_arg(args, ptrdiff_t);
 680                 } else if (qualifier == 'h') {
 681                         num = (unsigned short) va_arg(args, int);
 682                         if (flags & SIGN)
 683                                 num = (signed short) num;
 684                 } else {
 685                         num = va_arg(args, unsigned int);
 686                         if (flags & SIGN)
 687                                 num = (signed int) num;
 688                 }
 689                 str = number(str, num, base, field_width, precision, flags);
 690         }
 691         *str = '\0';
 692         return str-buf;
 693 }
 694
 695 /**
 696  * sprintf - Format a string and place it in a buffer
 697  * @buf: The buffer to place the result into
 698  * @fmt: The format string to use
 699  * @...: Arguments for the format string
 700  *
 701  * The function returns the number of characters written
 702  * into @buf.
 703  *
 704  * See the vsprintf() documentation for format string extensions over C99.
 705  */
 706 int sprintf(char * buf, const char *fmt, ...)
 707 {
 708         va_list args;
 709         int i;
 710
 711         va_start(args, fmt);
 712         i=vsprintf(buf,fmt,args);
 713         va_end(args);
 714         return i;
 715 }
 716
 717 void panic(const char *fmt, ...)
 718 {
 719         va_list args;
 720         va_start(args, fmt);
 721         vprintf(fmt, args);
 722         putc('\n');
 723         va_end(args);
 724 #if defined (CONFIG_PANIC_HANG)
 725         hang();
 726 #else
 727         udelay (100000);        /* allow messages to go out */
 728         do_reset (NULL, 0, 0, NULL);
 729 #endif
 730         while (1)
 731                 ;
 732 }
 733
 734 void __assert_fail(const char *assertion, const char *file, unsigned line,
 735                    const char *function)
 736 {
 737         /* This will not return */
 738         panic("%s:%u: %s: Assertion `%s' failed.", file, line, function,
 739               assertion);
 740 }