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 #include <net/addrconf.h>
  29
  30 #include <asm/page.h>           /* for PAGE_SIZE */
  31 #include <asm/div64.h>
  32 #include <asm/sections.h>       /* for dereference_function_descriptor() */
  33
  34 /* Works only for digits and letters, but small and fast */
  35 #define TOLOWER(x) ((x) | 0x20)
  36
  37 static unsigned int simple_guess_base(const char *cp)
  38 {
  39         if (cp[0] == '0') {
  40                 if (TOLOWER(cp[1]) == 'x' && isxdigit(cp[2]))
  41                         return 16;
  42                 else
  43                         return 8;
  44         } else {
  45                 return 10;
  46         }
  47 }
  48
  49 /**
  50  * simple_strtoull - convert a string to an unsigned long long
  51  * @cp: The start of the string
  52  * @endp: A pointer to the end of the parsed string will be placed here
  53  * @base: The number base to use
  54  */
  55 unsigned long long simple_strtoull(const char *cp, char **endp, unsigned int base)
  56 {
  57         unsigned long long result = 0;
  58
  59         if (!base)
  60                 base = simple_guess_base(cp);
  61
  62         if (base == 16 && cp[0] == '0' && TOLOWER(cp[1]) == 'x')
  63                 cp += 2;
  64
  65         while (isxdigit(*cp)) {
  66                 unsigned int value;
  67
  68                 value = isdigit(*cp) ? *cp - '0' : TOLOWER(*cp) - 'a' + 10;
  69                 if (value >= base)
  70                         break;
  71                 result = result * base + value;
  72                 cp++;
  73         }
  74         if (endp)
  75                 *endp = (char *)cp;
  76
  77         return result;
  78 }
  79 EXPORT_SYMBOL(simple_strtoull);
  80
  81 /**
  82  * simple_strtoul - convert a string to an unsigned long
  83  * @cp: The start of the string
  84  * @endp: A pointer to the end of the parsed string will be placed here
  85  * @base: The number base to use
  86  */
  87 unsigned long simple_strtoul(const char *cp, char **endp, unsigned int base)
  88 {
  89         return simple_strtoull(cp, endp, base);
  90 }
  91 EXPORT_SYMBOL(simple_strtoul);
  92
  93 /**
  94  * simple_strtol - convert a string to a signed long
  95  * @cp: The start of the string
  96  * @endp: A pointer to the end of the parsed string will be placed here
  97  * @base: The number base to use
  98  */
  99 long simple_strtol(const char *cp, char **endp, unsigned int base)
 100 {
 101         if (*cp == '-')
 102                 return -simple_strtoul(cp + 1, endp, base);
 103
 104         return simple_strtoul(cp, endp, base);
 105 }
 106 EXPORT_SYMBOL(simple_strtol);
 107
 108 /**
 109  * simple_strtoll - convert a string to a signed long long
 110  * @cp: The start of the string
 111  * @endp: A pointer to the end of the parsed string will be placed here
 112  * @base: The number base to use
 113  */
 114 long long simple_strtoll(const char *cp, char **endp, unsigned int base)
 115 {
 116         if (*cp == '-')
 117                 return -simple_strtoull(cp + 1, endp, base);
 118
 119         return simple_strtoull(cp, endp, base);
 120 }
 121 EXPORT_SYMBOL(simple_strtoll);
 122
 123 static noinline_for_stack
 124 int skip_atoi(const char **s)
 125 {
 126         int i = 0;
 127
 128         while (isdigit(**s))
 129                 i = i*10 + *((*s)++) - '0';
 130
 131         return i;
 132 }
 133
 134 /* Decimal conversion is by far the most typical, and is used
 135  * for /proc and /sys data. This directly impacts e.g. top performance
 136  * with many processes running. We optimize it for speed
 137  * using code from
 138  * http://www.cs.uiowa.edu/~jones/bcd/decimal.html
 139  * (with permission from the author, Douglas W. Jones). */
 140
 141 /* Formats correctly any integer in [0,99999].
 142  * Outputs from one to five digits depending on input.
 143  * On i386 gcc 4.1.2 -O2: ~250 bytes of code. */
 144 static noinline_for_stack
 145 char *put_dec_trunc(char *buf, unsigned q)
 146 {
 147         unsigned d3, d2, d1, d0;
 148         d1 = (q>>4) & 0xf;
 149         d2 = (q>>8) & 0xf;
 150         d3 = (q>>12);
 151
 152         d0 = 6*(d3 + d2 + d1) + (q & 0xf);
 153         q = (d0 * 0xcd) >> 11;
 154         d0 = d0 - 10*q;
 155         *buf++ = d0 + '0'; /* least significant digit */
 156         d1 = q + 9*d3 + 5*d2 + d1;
 157         if (d1 != 0) {
 158                 q = (d1 * 0xcd) >> 11;
 159                 d1 = d1 - 10*q;
 160                 *buf++ = d1 + '0'; /* next digit */
 161
 162                 d2 = q + 2*d2;
 163                 if ((d2 != 0) || (d3 != 0)) {
 164                         q = (d2 * 0xd) >> 7;
 165                         d2 = d2 - 10*q;
 166                         *buf++ = d2 + '0'; /* next digit */
 167
 168                         d3 = q + 4*d3;
 169                         if (d3 != 0) {
 170                                 q = (d3 * 0xcd) >> 11;
 171                                 d3 = d3 - 10*q;
 172                                 *buf++ = d3 + '0';  /* next digit */
 173                                 if (q != 0)
 174                                         *buf++ = q + '0'; /* most sign. digit */
 175                         }
 176                 }
 177         }
 178
 179         return buf;
 180 }
 181 /* Same with if's removed. Always emits five digits */
 182 static noinline_for_stack
 183 char *put_dec_full(char *buf, unsigned q)
 184 {
 185         /* BTW, if q is in [0,9999], 8-bit ints will be enough, */
 186         /* but anyway, gcc produces better code with full-sized ints */
 187         unsigned d3, d2, d1, d0;
 188         d1 = (q>>4) & 0xf;
 189         d2 = (q>>8) & 0xf;
 190         d3 = (q>>12);
 191
 192         /*
 193          * Possible ways to approx. divide by 10
 194          * gcc -O2 replaces multiply with shifts and adds
 195          * (x * 0xcd) >> 11: 11001101 - shorter code than * 0x67 (on i386)
 196          * (x * 0x67) >> 10:  1100111
 197          * (x * 0x34) >> 9:    110100 - same
 198          * (x * 0x1a) >> 8:     11010 - same
 199          * (x * 0x0d) >> 7:      1101 - same, shortest code (on i386)
 200          */
 201         d0 = 6*(d3 + d2 + d1) + (q & 0xf);
 202         q = (d0 * 0xcd) >> 11;
 203         d0 = d0 - 10*q;
 204         *buf++ = d0 + '0';
 205         d1 = q + 9*d3 + 5*d2 + d1;
 206                 q = (d1 * 0xcd) >> 11;
 207                 d1 = d1 - 10*q;
 208                 *buf++ = d1 + '0';
 209
 210                 d2 = q + 2*d2;
 211                         q = (d2 * 0xd) >> 7;
 212                         d2 = d2 - 10*q;
 213                         *buf++ = d2 + '0';
 214
 215                         d3 = q + 4*d3;
 216                                 q = (d3 * 0xcd) >> 11; /* - shorter code */
 217                                 /* q = (d3 * 0x67) >> 10; - would also work */
 218                                 d3 = d3 - 10*q;
 219                                 *buf++ = d3 + '0';
 220                                         *buf++ = q + '0';
 221
 222         return buf;
 223 }
 224 /* No inlining helps gcc to use registers better */
 225 static noinline_for_stack
 226 char *put_dec(char *buf, unsigned long long num)
 227 {
 228         while (1) {
 229                 unsigned rem;
 230                 if (num < 100000)
 231                         return put_dec_trunc(buf, num);
 232                 rem = do_div(num, 100000);
 233                 buf = put_dec_full(buf, rem);
 234         }
 235 }
 236
 237 #define ZEROPAD 1               /* pad with zero */
 238 #define SIGN    2               /* unsigned/signed long */
 239 #define PLUS    4               /* show plus */
 240 #define SPACE   8               /* space if plus */
 241 #define LEFT    16              /* left justified */
 242 #define SMALL   32              /* use lowercase in hex (must be 32 == 0x20) */
 243 #define SPECIAL 64              /* prefix hex with "0x", octal with "0" */
 244
 245 enum format_type {
 246         FORMAT_TYPE_NONE, /* Just a string part */
 247         FORMAT_TYPE_WIDTH,
 248         FORMAT_TYPE_PRECISION,
 249         FORMAT_TYPE_CHAR,
 250         FORMAT_TYPE_STR,
 251         FORMAT_TYPE_PTR,
 252         FORMAT_TYPE_PERCENT_CHAR,
 253         FORMAT_TYPE_INVALID,
 254         FORMAT_TYPE_LONG_LONG,
 255         FORMAT_TYPE_ULONG,
 256         FORMAT_TYPE_LONG,
 257         FORMAT_TYPE_UBYTE,
 258         FORMAT_TYPE_BYTE,
 259         FORMAT_TYPE_USHORT,
 260         FORMAT_TYPE_SHORT,
 261         FORMAT_TYPE_UINT,
 262         FORMAT_TYPE_INT,
 263         FORMAT_TYPE_NRCHARS,
 264         FORMAT_TYPE_SIZE_T,
 265         FORMAT_TYPE_PTRDIFF
 266 };
 267
 268 struct printf_spec {
 269         u8      type;           /* format_type enum */
 270         u8      flags;          /* flags to number() */
 271         u8      base;           /* number base, 8, 10 or 16 only */
 272         u8      qualifier;      /* number qualifier, one of 'hHlLtzZ' */
 273         s16     field_width;    /* width of output field */
 274         s16     precision;      /* # of digits/chars */
 275 };
 276
 277 static noinline_for_stack
 278 char *number(char *buf, char *end, unsigned long long num,
 279              struct printf_spec spec)
 280 {
 281         /* we are called with base 8, 10 or 16, only, thus don't need "G..."  */
 282         static const char digits[16] = "0123456789ABCDEF"; /* "GHIJKLMNOPQRSTUVWXYZ"; */
 283
 284         char tmp[66];
 285         char sign;
 286         char locase;
 287         int need_pfx = ((spec.flags & SPECIAL) && spec.base != 10);
 288         int i;
 289
 290         /* locase = 0 or 0x20. ORing digits or letters with 'locase'
 291          * produces same digits or (maybe lowercased) letters */
 292         locase = (spec.flags & SMALL);
 293         if (spec.flags & LEFT)
 294                 spec.flags &= ~ZEROPAD;
 295         sign = 0;
 296         if (spec.flags & SIGN) {
 297                 if ((signed long long)num < 0) {
 298                         sign = '-';
 299                         num = -(signed long long)num;
 300                         spec.field_width--;
 301                 } else if (spec.flags & PLUS) {
 302                         sign = '+';
 303                         spec.field_width--;
 304                 } else if (spec.flags & SPACE) {
 305                         sign = ' ';
 306                         spec.field_width--;
 307                 }
 308         }
 309         if (need_pfx) {
 310                 spec.field_width--;
 311                 if (spec.base == 16)
 312                         spec.field_width--;
 313         }
 314
 315         /* generate full string in tmp[], in reverse order */
 316         i = 0;
 317         if (num == 0)
 318                 tmp[i++] = '0';
 319         /* Generic code, for any base:
 320         else do {
 321                 tmp[i++] = (digits[do_div(num,base)] | locase);
 322         } while (num != 0);
 323         */
 324         else if (spec.base != 10) { /* 8 or 16 */
 325                 int mask = spec.base - 1;
 326                 int shift = 3;
 327
 328                 if (spec.base == 16)
 329                         shift = 4;
 330                 do {
 331                         tmp[i++] = (digits[((unsigned char)num) & mask] | locase);
 332                         num >>= shift;
 333                 } while (num);
 334         } else { /* base 10 */
 335                 i = put_dec(tmp, num) - tmp;
 336         }
 337
 338         /* printing 100 using %2d gives "100", not "00" */
 339         if (i > spec.precision)
 340                 spec.precision = i;
 341         /* leading space padding */
 342         spec.field_width -= spec.precision;
 343         if (!(spec.flags & (ZEROPAD+LEFT))) {
 344                 while (--spec.field_width >= 0) {
 345                         if (buf < end)
 346                                 *buf = ' ';
 347                         ++buf;
 348                 }
 349         }
 350         /* sign */
 351         if (sign) {
 352                 if (buf < end)
 353                         *buf = sign;
 354                 ++buf;
 355         }
 356         /* "0x" / "0" prefix */
 357         if (need_pfx) {
 358                 if (buf < end)
 359                         *buf = '0';
 360                 ++buf;
 361                 if (spec.base == 16) {
 362                         if (buf < end)
 363                                 *buf = ('X' | locase);
 364                         ++buf;
 365                 }
 366         }
 367         /* zero or space padding */
 368         if (!(spec.flags & LEFT)) {
 369                 char c = (spec.flags & ZEROPAD) ? '0' : ' ';
 370                 while (--spec.field_width >= 0) {
 371                         if (buf < end)
 372                                 *buf = c;
 373                         ++buf;
 374                 }
 375         }
 376         /* hmm even more zero padding? */
 377         while (i <= --spec.precision) {
 378                 if (buf < end)
 379                         *buf = '0';
 380                 ++buf;
 381         }
 382         /* actual digits of result */
 383         while (--i >= 0) {
 384                 if (buf < end)
 385                         *buf = tmp[i];
 386                 ++buf;
 387         }
 388         /* trailing space padding */
 389         while (--spec.field_width >= 0) {
 390                 if (buf < end)
 391                         *buf = ' ';
 392                 ++buf;
 393         }
 394
 395         return buf;
 396 }
 397
 398 static noinline_for_stack
 399 char *string(char *buf, char *end, const char *s, struct printf_spec spec)
 400 {
 401         int len, i;
 402
 403         if ((unsigned long)s < PAGE_SIZE)
 404                 s = "(null)";
 405
 406         len = strnlen(s, spec.precision);
 407
 408         if (!(spec.flags & LEFT)) {
 409                 while (len < spec.field_width--) {
 410                         if (buf < end)
 411                                 *buf = ' ';
 412                         ++buf;
 413                 }
 414         }
 415         for (i = 0; i < len; ++i) {
 416                 if (buf < end)
 417                         *buf = *s;
 418                 ++buf; ++s;
 419         }
 420         while (len < spec.field_width--) {
 421                 if (buf < end)
 422                         *buf = ' ';
 423                 ++buf;
 424         }
 425
 426         return buf;
 427 }
 428
 429 static noinline_for_stack
 430 char *symbol_string(char *buf, char *end, void *ptr,
 431                     struct printf_spec spec, char ext)
 432 {
 433         unsigned long value = (unsigned long) ptr;
 434 #ifdef CONFIG_KALLSYMS
 435         char sym[KSYM_SYMBOL_LEN];
 436         if (ext == 'B')
 437                 sprint_backtrace(sym, value);
 438         else if (ext != 'f' && ext != 's')
 439                 sprint_symbol(sym, value);
 440         else
 441                 kallsyms_lookup(value, NULL, NULL, NULL, sym);
 442
 443         return string(buf, end, sym, spec);
 444 #else
 445         spec.field_width = 2 * sizeof(void *);
 446         spec.flags |= SPECIAL | SMALL | ZEROPAD;
 447         spec.base = 16;
 448
 449         return number(buf, end, value, spec);
 450 #endif
 451 }
 452
 453 static noinline_for_stack
 454 char *resource_string(char *buf, char *end, struct resource *res,
 455                       struct printf_spec spec, const char *fmt)
 456 {
 457 #ifndef IO_RSRC_PRINTK_SIZE
 458 #define IO_RSRC_PRINTK_SIZE     6
 459 #endif
 460
 461 #ifndef MEM_RSRC_PRINTK_SIZE
 462 #define MEM_RSRC_PRINTK_SIZE    10
 463 #endif
 464         static const struct printf_spec io_spec = {
 465                 .base = 16,
 466                 .field_width = IO_RSRC_PRINTK_SIZE,
 467                 .precision = -1,
 468                 .flags = SPECIAL | SMALL | ZEROPAD,
 469         };
 470         static const struct printf_spec mem_spec = {
 471                 .base = 16,
 472                 .field_width = MEM_RSRC_PRINTK_SIZE,
 473                 .precision = -1,
 474                 .flags = SPECIAL | SMALL | ZEROPAD,
 475         };
 476         static const struct printf_spec bus_spec = {
 477                 .base = 16,
 478                 .field_width = 2,
 479                 .precision = -1,
 480                 .flags = SMALL | ZEROPAD,
 481         };
 482         static const struct printf_spec dec_spec = {
 483                 .base = 10,
 484                 .precision = -1,
 485                 .flags = 0,
 486         };
 487         static const struct printf_spec str_spec = {
 488                 .field_width = -1,
 489                 .precision = 10,
 490                 .flags = LEFT,
 491         };
 492         static const struct printf_spec flag_spec = {
 493                 .base = 16,
 494                 .precision = -1,
 495                 .flags = SPECIAL | SMALL,
 496         };
 497
 498         /* 32-bit res (sizeof==4): 10 chars in dec, 10 in hex ("0x" + 8)
 499          * 64-bit res (sizeof==8): 20 chars in dec, 18 in hex ("0x" + 16) */
 500 #define RSRC_BUF_SIZE           ((2 * sizeof(resource_size_t)) + 4)
 501 #define FLAG_BUF_SIZE           (2 * sizeof(res->flags))
 502 #define DECODED_BUF_SIZE        sizeof("[mem - 64bit pref window disabled]")
 503 #define RAW_BUF_SIZE            sizeof("[mem - flags 0x]")
 504         char sym[max(2*RSRC_BUF_SIZE + DECODED_BUF_SIZE,
 505                      2*RSRC_BUF_SIZE + FLAG_BUF_SIZE + RAW_BUF_SIZE)];
 506
 507         char *p = sym, *pend = sym + sizeof(sym);
 508         int decode = (fmt[0] == 'R') ? 1 : 0;
 509         const struct printf_spec *specp;
 510
 511         *p++ = '[';
 512         if (res->flags & IORESOURCE_IO) {
 513                 p = string(p, pend, "io  ", str_spec);
 514                 specp = &io_spec;
 515         } else if (res->flags & IORESOURCE_MEM) {
 516                 p = string(p, pend, "mem ", str_spec);
 517                 specp = &mem_spec;
 518         } else if (res->flags & IORESOURCE_IRQ) {
 519                 p = string(p, pend, "irq ", str_spec);
 520                 specp = &dec_spec;
 521         } else if (res->flags & IORESOURCE_DMA) {
 522                 p = string(p, pend, "dma ", str_spec);
 523                 specp = &dec_spec;
 524         } else if (res->flags & IORESOURCE_BUS) {
 525                 p = string(p, pend, "bus ", str_spec);
 526                 specp = &bus_spec;
 527         } else {
 528                 p = string(p, pend, "??? ", str_spec);
 529                 specp = &mem_spec;
 530                 decode = 0;
 531         }
 532         p = number(p, pend, res->start, *specp);
 533         if (res->start != res->end) {
 534                 *p++ = '-';
 535                 p = number(p, pend, res->end, *specp);
 536         }
 537         if (decode) {
 538                 if (res->flags & IORESOURCE_MEM_64)
 539                         p = string(p, pend, " 64bit", str_spec);
 540                 if (res->flags & IORESOURCE_PREFETCH)
 541                         p = string(p, pend, " pref", str_spec);
 542                 if (res->flags & IORESOURCE_WINDOW)
 543                         p = string(p, pend, " window", str_spec);
 544                 if (res->flags & IORESOURCE_DISABLED)
 545                         p = string(p, pend, " disabled", str_spec);
 546         } else {
 547                 p = string(p, pend, " flags ", str_spec);
 548                 p = number(p, pend, res->flags, flag_spec);
 549         }
 550         *p++ = ']';
 551         *p = '\0';
 552
 553         return string(buf, end, sym, spec);
 554 }
 555
 556 static noinline_for_stack
 557 char *mac_address_string(char *buf, char *end, u8 *addr,
 558                          struct printf_spec spec, const char *fmt)
 559 {
 560         char mac_addr[sizeof("xx:xx:xx:xx:xx:xx")];
 561         char *p = mac_addr;
 562         int i;
 563         char separator;
 564
 565         if (fmt[1] == 'F') {            /* FDDI canonical format */
 566                 separator = '-';
 567         } else {
 568                 separator = ':';
 569         }
 570
 571         for (i = 0; i < 6; i++) {
 572                 p = pack_hex_byte(p, addr[i]);
 573                 if (fmt[0] == 'M' && i != 5)
 574                         *p++ = separator;
 575         }
 576         *p = '\0';
 577
 578         return string(buf, end, mac_addr, spec);
 579 }
 580
 581 static noinline_for_stack
 582 char *ip4_string(char *p, const u8 *addr, const char *fmt)
 583 {
 584         int i;
 585         bool leading_zeros = (fmt[0] == 'i');
 586         int index;
 587         int step;
 588
 589         switch (fmt[2]) {
 590         case 'h':
 591 #ifdef __BIG_ENDIAN
 592                 index = 0;
 593                 step = 1;
 594 #else
 595                 index = 3;
 596                 step = -1;
 597 #endif
 598                 break;
 599         case 'l':
 600                 index = 3;
 601                 step = -1;
 602                 break;
 603         case 'n':
 604         case 'b':
 605         default:
 606                 index = 0;
 607                 step = 1;
 608                 break;
 609         }
 610         for (i = 0; i < 4; i++) {
 611                 char temp[3];   /* hold each IP quad in reverse order */
 612                 int digits = put_dec_trunc(temp, addr[index]) - temp;
 613                 if (leading_zeros) {
 614                         if (digits < 3)
 615                                 *p++ = '0';
 616                         if (digits < 2)
 617                                 *p++ = '0';
 618                 }
 619                 /* reverse the digits in the quad */
 620                 while (digits--)
 621                         *p++ = temp[digits];
 622                 if (i < 3)
 623                         *p++ = '.';
 624                 index += step;
 625         }
 626         *p = '\0';
 627
 628         return p;
 629 }
 630
 631 static noinline_for_stack
 632 char *ip6_compressed_string(char *p, const char *addr)
 633 {
 634         int i, j, range;
 635         unsigned char zerolength[8];
 636         int longest = 1;
 637         int colonpos = -1;
 638         u16 word;
 639         u8 hi, lo;
 640         bool needcolon = false;
 641         bool useIPv4;
 642         struct in6_addr in6;
 643
 644         memcpy(&in6, addr, sizeof(struct in6_addr));
 645
 646         useIPv4 = ipv6_addr_v4mapped(&in6) || ipv6_addr_is_isatap(&in6);
 647
 648         memset(zerolength, 0, sizeof(zerolength));
 649
 650         if (useIPv4)
 651                 range = 6;
 652         else
 653                 range = 8;
 654
 655         /* find position of longest 0 run */
 656         for (i = 0; i < range; i++) {
 657                 for (j = i; j < range; j++) {
 658                         if (in6.s6_addr16[j] != 0)
 659                                 break;
 660                         zerolength[i]++;
 661                 }
 662         }
 663         for (i = 0; i < range; i++) {
 664                 if (zerolength[i] > longest) {
 665                         longest = zerolength[i];
 666                         colonpos = i;
 667                 }
 668         }
 669
 670         /* emit address */
 671         for (i = 0; i < range; i++) {
 672                 if (i == colonpos) {
 673                         if (needcolon || i == 0)
 674                                 *p++ = ':';
 675                         *p++ = ':';
 676                         needcolon = false;
 677                         i += longest - 1;
 678                         continue;
 679                 }
 680                 if (needcolon) {
 681                         *p++ = ':';
 682                         needcolon = false;
 683                 }
 684                 /* hex u16 without leading 0s */
 685                 word = ntohs(in6.s6_addr16[i]);
 686                 hi = word >> 8;
 687                 lo = word & 0xff;
 688                 if (hi) {
 689                         if (hi > 0x0f)
 690                                 p = pack_hex_byte(p, hi);
 691                         else
 692                                 *p++ = hex_asc_lo(hi);
 693                         p = pack_hex_byte(p, lo);
 694                 }
 695                 else if (lo > 0x0f)
 696                         p = pack_hex_byte(p, lo);
 697                 else
 698                         *p++ = hex_asc_lo(lo);
 699                 needcolon = true;
 700         }
 701
 702         if (useIPv4) {
 703                 if (needcolon)
 704                         *p++ = ':';
 705                 p = ip4_string(p, &in6.s6_addr[12], "I4");
 706         }
 707         *p = '\0';
 708
 709         return p;
 710 }
 711
 712 static noinline_for_stack
 713 char *ip6_string(char *p, const char *addr, const char *fmt)
 714 {
 715         int i;
 716
 717         for (i = 0; i < 8; i++) {
 718                 p = pack_hex_byte(p, *addr++);
 719                 p = pack_hex_byte(p, *addr++);
 720                 if (fmt[0] == 'I' && i != 7)
 721                         *p++ = ':';
 722         }
 723         *p = '\0';
 724
 725         return p;
 726 }
 727
 728 static noinline_for_stack
 729 char *ip6_addr_string(char *buf, char *end, const u8 *addr,
 730                       struct printf_spec spec, const char *fmt)
 731 {
 732         char ip6_addr[sizeof("xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:255.255.255.255")];
 733
 734         if (fmt[0] == 'I' && fmt[2] == 'c')
 735                 ip6_compressed_string(ip6_addr, addr);
 736         else
 737                 ip6_string(ip6_addr, addr, fmt);
 738
 739         return string(buf, end, ip6_addr, spec);
 740 }
 741
 742 static noinline_for_stack
 743 char *ip4_addr_string(char *buf, char *end, const u8 *addr,
 744                       struct printf_spec spec, const char *fmt)
 745 {
 746         char ip4_addr[sizeof("255.255.255.255")];
 747
 748         ip4_string(ip4_addr, addr, fmt);
 749
 750         return string(buf, end, ip4_addr, spec);
 751 }
 752
 753 static noinline_for_stack
 754 char *uuid_string(char *buf, char *end, const u8 *addr,
 755                   struct printf_spec spec, const char *fmt)
 756 {
 757         char uuid[sizeof("xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx")];
 758         char *p = uuid;
 759         int i;
 760         static const u8 be[16] = {0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15};
 761         static const u8 le[16] = {3,2,1,0,5,4,7,6,8,9,10,11,12,13,14,15};
 762         const u8 *index = be;
 763         bool uc = false;
 764
 765         switch (*(++fmt)) {
 766         case 'L':
 767                 uc = true;              /* fall-through */
 768         case 'l':
 769                 index = le;
 770                 break;
 771         case 'B':
 772                 uc = true;
 773                 break;
 774         }
 775
 776         for (i = 0; i < 16; i++) {
 777                 p = pack_hex_byte(p, addr[index[i]]);
 778                 switch (i) {
 779                 case 3:
 780                 case 5:
 781                 case 7:
 782                 case 9:
 783                         *p++ = '-';
 784                         break;
 785                 }
 786         }
 787
 788         *p = 0;
 789
 790         if (uc) {
 791                 p = uuid;
 792                 do {
 793                         *p = toupper(*p);
 794                 } while (*(++p));
 795         }
 796
 797         return string(buf, end, uuid, spec);
 798 }
 799
 800 int kptr_restrict __read_mostly;
 801
 802 /*
 803  * Show a '%p' thing.  A kernel extension is that the '%p' is followed
 804  * by an extra set of alphanumeric characters that are extended format
 805  * specifiers.
 806  *
 807  * Right now we handle:
 808  *
 809  * - 'F' For symbolic function descriptor pointers with offset
 810  * - 'f' For simple symbolic function names without offset
 811  * - 'S' For symbolic direct pointers with offset
 812  * - 's' For symbolic direct pointers without offset
 813  * - 'B' For backtraced symbolic direct pointers with offset
 814  * - 'R' For decoded struct resource, e.g., [mem 0x0-0x1f 64bit pref]
 815  * - 'r' For raw struct resource, e.g., [mem 0x0-0x1f flags 0x201]
 816  * - 'M' For a 6-byte MAC address, it prints the address in the
 817  *       usual colon-separated hex notation
 818  * - 'm' For a 6-byte MAC address, it prints the hex address without colons
 819  * - 'MF' For a 6-byte MAC FDDI address, it prints the address
 820  *       with a dash-separated hex notation
 821  * - 'I' [46] for IPv4/IPv6 addresses printed in the usual way
 822  *       IPv4 uses dot-separated decimal without leading 0's (1.2.3.4)
 823  *       IPv6 uses colon separated network-order 16 bit hex with leading 0's
 824  * - 'i' [46] for 'raw' IPv4/IPv6 addresses
 825  *       IPv6 omits the colons (01020304...0f)
 826  *       IPv4 uses dot-separated decimal with leading 0's (010.123.045.006)
 827  * - '[Ii]4[hnbl]' IPv4 addresses in host, network, big or little endian order
 828  * - 'I6c' for IPv6 addresses printed as specified by
 829  *       http://tools.ietf.org/html/draft-ietf-6man-text-addr-representation-00
 830  * - 'U' For a 16 byte UUID/GUID, it prints the UUID/GUID in the form
 831  *       "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx"
 832  *       Options for %pU are:
 833  *         b big endian lower case hex (default)
 834  *         B big endian UPPER case hex
 835  *         l little endian lower case hex
 836  *         L little endian UPPER case hex
 837  *           big endian output byte order is:
 838  *             [0][1][2][3]-[4][5]-[6][7]-[8][9]-[10][11][12][13][14][15]
 839  *           little endian output byte order is:
 840  *             [3][2][1][0]-[5][4]-[7][6]-[8][9]-[10][11][12][13][14][15]
 841  * - 'V' For a struct va_format which contains a format string * and va_list *,
 842  *       call vsnprintf(->format, *->va_list).
 843  *       Implements a "recursive vsnprintf".
 844  *       Do not use this feature without some mechanism to verify the
 845  *       correctness of the format string and va_list arguments.
 846  * - 'K' For a kernel pointer that should be hidden from unprivileged users
 847  *
 848  * Note: The difference between 'S' and 'F' is that on ia64 and ppc64
 849  * function pointers are really function descriptors, which contain a
 850  * pointer to the real address.
 851  */
 852 static noinline_for_stack
 853 char *pointer(const char *fmt, char *buf, char *end, void *ptr,
 854               struct printf_spec spec)
 855 {
 856         if (!ptr && *fmt != 'K') {
 857                 /*
 858                  * Print (null) with the same width as a pointer so it makes
 859                  * tabular output look nice.
 860                  */
 861                 if (spec.field_width == -1)
 862                         spec.field_width = 2 * sizeof(void *);
 863                 return string(buf, end, "(null)", spec);
 864         }
 865
 866         switch (*fmt) {
 867         case 'F':
 868         case 'f':
 869                 ptr = dereference_function_descriptor(ptr);
 870                 /* Fallthrough */
 871         case 'S':
 872         case 's':
 873         case 'B':
 874                 return symbol_string(buf, end, ptr, spec, *fmt);
 875         case 'R':
 876         case 'r':
 877                 return resource_string(buf, end, ptr, spec, fmt);
 878         case 'M':                       /* Colon separated: 00:01:02:03:04:05 */
 879         case 'm':                       /* Contiguous: 000102030405 */
 880                                         /* [mM]F (FDDI, bit reversed) */
 881                 return mac_address_string(buf, end, ptr, spec, fmt);
 882         case 'I':                       /* Formatted IP supported
 883                                          * 4:   1.2.3.4
 884                                          * 6:   0001:0203:...:0708
 885                                          * 6c:  1::708 or 1::1.2.3.4
 886                                          */
 887         case 'i':                       /* Contiguous:
 888                                          * 4:   001.002.003.004
 889                                          * 6:   000102...0f
 890                                          */
 891                 switch (fmt[1]) {
 892                 case '6':
 893                         return ip6_addr_string(buf, end, ptr, spec, fmt);
 894                 case '4':
 895                         return ip4_addr_string(buf, end, ptr, spec, fmt);
 896                 }
 897                 break;
 898         case 'U':
 899                 return uuid_string(buf, end, ptr, spec, fmt);
 900         case 'V':
 901                 return buf + vsnprintf(buf, end - buf,
 902                                        ((struct va_format *)ptr)->fmt,
 903                                        *(((struct va_format *)ptr)->va));
 904         case 'K':
 905                 /*
 906                  * %pK cannot be used in IRQ context because its test
 907                  * for CAP_SYSLOG would be meaningless.
 908                  */
 909                 if (in_irq() || in_serving_softirq() || in_nmi()) {
 910                         if (spec.field_width == -1)
 911                                 spec.field_width = 2 * sizeof(void *);
 912                         return string(buf, end, "pK-error", spec);
 913                 }
 914                 if (!((kptr_restrict == 0) ||
 915                       (kptr_restrict == 1 &&
 916                        has_capability_noaudit(current, CAP_SYSLOG))))
 917                         ptr = NULL;
 918                 break;
 919         }
 920         spec.flags |= SMALL;
 921         if (spec.field_width == -1) {
 922                 spec.field_width = 2 * sizeof(void *);
 923                 spec.flags |= ZEROPAD;
 924         }
 925         spec.base = 16;
 926
 927         return number(buf, end, (unsigned long) ptr, spec);
 928 }
 929
 930 /*
 931  * Helper function to decode printf style format.
 932  * Each call decode a token from the format and return the
 933  * number of characters read (or likely the delta where it wants
 934  * to go on the next call).
 935  * The decoded token is returned through the parameters
 936  *
 937  * 'h', 'l', or 'L' for integer fields
 938  * 'z' support added 23/7/1999 S.H.
 939  * 'z' changed to 'Z' --davidm 1/25/99
 940  * 't' added for ptrdiff_t
 941  *
 942  * @fmt: the format string
 943  * @type of the token returned
 944  * @flags: various flags such as +, -, # tokens..
 945  * @field_width: overwritten width
 946  * @base: base of the number (octal, hex, ...)
 947  * @precision: precision of a number
 948  * @qualifier: qualifier of a number (long, size_t, ...)
 949  */
 950 static noinline_for_stack
 951 int format_decode(const char *fmt, struct printf_spec *spec)
 952 {
 953         const char *start = fmt;
 954
 955         /* we finished early by reading the field width */
 956         if (spec->type == FORMAT_TYPE_WIDTH) {
 957                 if (spec->field_width < 0) {
 958                         spec->field_width = -spec->field_width;
 959                         spec->flags |= LEFT;
 960                 }
 961                 spec->type = FORMAT_TYPE_NONE;
 962                 goto precision;
 963         }
 964
 965         /* we finished early by reading the precision */
 966         if (spec->type == FORMAT_TYPE_PRECISION) {
 967                 if (spec->precision < 0)
 968                         spec->precision = 0;
 969
 970                 spec->type = FORMAT_TYPE_NONE;
 971                 goto qualifier;
 972         }
 973
 974         /* By default */
 975         spec->type = FORMAT_TYPE_NONE;
 976
 977         for (; *fmt ; ++fmt) {
 978                 if (*fmt == '%')
 979                         break;
 980         }
 981
 982         /* Return the current non-format string */
 983         if (fmt != start || !*fmt)
 984                 return fmt - start;
 985
 986         /* Process flags */
 987         spec->flags = 0;
 988
 989         while (1) { /* this also skips first '%' */
 990                 bool found = true;
 991
 992                 ++fmt;
 993
 994                 switch (*fmt) {
 995                 case '-': spec->flags |= LEFT;    break;
 996                 case '+': spec->flags |= PLUS;    break;
 997                 case ' ': spec->flags |= SPACE;   break;
 998                 case '#': spec->flags |= SPECIAL; break;
 999                 case '0': spec->flags |= ZEROPAD; break;
1000                 default:  found = false;
1001                 }
1002
1003                 if (!found)
1004                         break;
1005         }
1006
1007         /* get field width */
1008         spec->field_width = -1;
1009
1010         if (isdigit(*fmt))
1011                 spec->field_width = skip_atoi(&fmt);
1012         else if (*fmt == '*') {
1013                 /* it's the next argument */
1014                 spec->type = FORMAT_TYPE_WIDTH;
1015                 return ++fmt - start;
1016         }
1017
1018 precision:
1019         /* get the precision */
1020         spec->precision = -1;
1021         if (*fmt == '.') {
1022                 ++fmt;
1023                 if (isdigit(*fmt)) {
1024                         spec->precision = skip_atoi(&fmt);
1025                         if (spec->precision < 0)
1026                                 spec->precision = 0;
1027                 } else if (*fmt == '*') {
1028                         /* it's the next argument */
1029                         spec->type = FORMAT_TYPE_PRECISION;
1030                         return ++fmt - start;
1031                 }
1032         }
1033
1034 qualifier:
1035         /* get the conversion qualifier */
1036         spec->qualifier = -1;
1037         if (*fmt == 'h' || TOLOWER(*fmt) == 'l' ||
1038             TOLOWER(*fmt) == 'z' || *fmt == 't') {
1039                 spec->qualifier = *fmt++;
1040                 if (unlikely(spec->qualifier == *fmt)) {
1041                         if (spec->qualifier == 'l') {
1042                                 spec->qualifier = 'L';
1043                                 ++fmt;
1044                         } else if (spec->qualifier == 'h') {
1045                                 spec->qualifier = 'H';
1046                                 ++fmt;
1047                         }
1048                 }
1049         }
1050
1051         /* default base */
1052         spec->base = 10;
1053         switch (*fmt) {
1054         case 'c':
1055                 spec->type = FORMAT_TYPE_CHAR;
1056                 return ++fmt - start;
1057
1058         case 's':
1059                 spec->type = FORMAT_TYPE_STR;
1060                 return ++fmt - start;
1061
1062         case 'p':
1063                 spec->type = FORMAT_TYPE_PTR;
1064                 return fmt - start;
1065                 /* skip alnum */
1066
1067         case 'n':
1068                 spec->type = FORMAT_TYPE_NRCHARS;
1069                 return ++fmt - start;
1070
1071         case '%':
1072                 spec->type = FORMAT_TYPE_PERCENT_CHAR;
1073                 return ++fmt - start;
1074
1075         /* integer number formats - set up the flags and "break" */
1076         case 'o':
1077                 spec->base = 8;
1078                 break;
1079
1080         case 'x':
1081                 spec->flags |= SMALL;
1082
1083         case 'X':
1084                 spec->base = 16;
1085                 break;
1086
1087         case 'd':
1088         case 'i':
1089                 spec->flags |= SIGN;
1090         case 'u':
1091                 break;
1092
1093         default:
1094                 spec->type = FORMAT_TYPE_INVALID;
1095                 return fmt - start;
1096         }
1097
1098         if (spec->qualifier == 'L')
1099                 spec->type = FORMAT_TYPE_LONG_LONG;
1100         else if (spec->qualifier == 'l') {
1101                 if (spec->flags & SIGN)
1102                         spec->type = FORMAT_TYPE_LONG;
1103                 else
1104                         spec->type = FORMAT_TYPE_ULONG;
1105         } else if (TOLOWER(spec->qualifier) == 'z') {
1106                 spec->type = FORMAT_TYPE_SIZE_T;
1107         } else if (spec->qualifier == 't') {
1108                 spec->type = FORMAT_TYPE_PTRDIFF;
1109         } else if (spec->qualifier == 'H') {
1110                 if (spec->flags & SIGN)
1111                         spec->type = FORMAT_TYPE_BYTE;
1112                 else
1113                         spec->type = FORMAT_TYPE_UBYTE;
1114         } else if (spec->qualifier == 'h') {
1115                 if (spec->flags & SIGN)
1116                         spec->type = FORMAT_TYPE_SHORT;
1117                 else
1118                         spec->type = FORMAT_TYPE_USHORT;
1119         } else {
1120                 if (spec->flags & SIGN)
1121                         spec->type = FORMAT_TYPE_INT;
1122                 else
1123                         spec->type = FORMAT_TYPE_UINT;
1124         }
1125
1126         return ++fmt - start;
1127 }
1128
1129 /**
1130  * vsnprintf - Format a string and place it in a buffer
1131  * @buf: The buffer to place the result into
1132  * @size: The size of the buffer, including the trailing null space
1133  * @fmt: The format string to use
1134  * @args: Arguments for the format string
1135  *
1136  * This function follows C99 vsnprintf, but has some extensions:
1137  * %pS output the name of a text symbol with offset
1138  * %ps output the name of a text symbol without offset
1139  * %pF output the name of a function pointer with its offset
1140  * %pf output the name of a function pointer without its offset
1141  * %pB output the name of a backtrace symbol with its offset
1142  * %pR output the address range in a struct resource with decoded flags
1143  * %pr output the address range in a struct resource with raw flags
1144  * %pM output a 6-byte MAC address with colons
1145  * %pm output a 6-byte MAC address without colons
1146  * %pI4 print an IPv4 address without leading zeros
1147  * %pi4 print an IPv4 address with leading zeros
1148  * %pI6 print an IPv6 address with colons
1149  * %pi6 print an IPv6 address without colons
1150  * %pI6c print an IPv6 address as specified by
1151  *   http://tools.ietf.org/html/draft-ietf-6man-text-addr-representation-00
1152  * %pU[bBlL] print a UUID/GUID in big or little endian using lower or upper
1153  *   case.
1154  * %n is ignored
1155  *
1156  * The return value is the number of characters which would
1157  * be generated for the given input, excluding the trailing
1158  * '\0', as per ISO C99. If you want to have the exact
1159  * number of characters written into @buf as return value
1160  * (not including the trailing '\0'), use vscnprintf(). If the
1161  * return is greater than or equal to @size, the resulting
1162  * string is truncated.
1163  *
1164  * Call this function if you are already dealing with a va_list.
1165  * You probably want snprintf() instead.
1166  */
1167 int vsnprintf(char *buf, size_t size, const char *fmt, va_list args)
1168 {
1169         unsigned long long num;
1170         char *str, *end;
1171         struct printf_spec spec = {0};
1172
1173         /* Reject out-of-range values early.  Large positive sizes are
1174            used for unknown buffer sizes. */
1175         if (WARN_ON_ONCE((int) size < 0))
1176                 return 0;
1177
1178         str = buf;
1179         end = buf + size;
1180
1181         /* Make sure end is always >= buf */
1182         if (end < buf) {
1183                 end = ((void *)-1);
1184                 size = end - buf;
1185         }
1186
1187         while (*fmt) {
1188                 const char *old_fmt = fmt;
1189                 int read = format_decode(fmt, &spec);
1190
1191                 fmt += read;
1192
1193                 switch (spec.type) {
1194                 case FORMAT_TYPE_NONE: {
1195                         int copy = read;
1196                         if (str < end) {
1197                                 if (copy > end - str)
1198                                         copy = end - str;
1199                                 memcpy(str, old_fmt, copy);
1200                         }
1201                         str += read;
1202                         break;
1203                 }
1204
1205                 case FORMAT_TYPE_WIDTH:
1206                         spec.field_width = va_arg(args, int);
1207                         break;
1208
1209                 case FORMAT_TYPE_PRECISION:
1210                         spec.precision = va_arg(args, int);
1211                         break;
1212
1213                 case FORMAT_TYPE_CHAR: {
1214                         char c;
1215
1216                         if (!(spec.flags & LEFT)) {
1217                                 while (--spec.field_width > 0) {
1218                                         if (str < end)
1219                                                 *str = ' ';
1220                                         ++str;
1221
1222                                 }
1223                         }
1224                         c = (unsigned char) va_arg(args, int);
1225                         if (str < end)
1226                                 *str = c;
1227                         ++str;
1228                         while (--spec.field_width > 0) {
1229                                 if (str < end)
1230                                         *str = ' ';
1231                                 ++str;
1232                         }
1233                         break;
1234                 }
1235
1236                 case FORMAT_TYPE_STR:
1237                         str = string(str, end, va_arg(args, char *), spec);
1238                         break;
1239
1240                 case FORMAT_TYPE_PTR:
1241                         str = pointer(fmt+1, str, end, va_arg(args, void *),
1242                                       spec);
1243                         while (isalnum(*fmt))
1244                                 fmt++;
1245                         break;
1246
1247                 case FORMAT_TYPE_PERCENT_CHAR:
1248                         if (str < end)
1249                                 *str = '%';
1250                         ++str;
1251                         break;
1252
1253                 case FORMAT_TYPE_INVALID:
1254                         if (str < end)
1255                                 *str = '%';
1256                         ++str;
1257                         break;
1258
1259                 case FORMAT_TYPE_NRCHARS: {
1260                         u8 qualifier = spec.qualifier;
1261
1262                         if (qualifier == 'l') {
1263                                 long *ip = va_arg(args, long *);
1264                                 *ip = (str - buf);
1265                         } else if (TOLOWER(qualifier) == 'z') {
1266                                 size_t *ip = va_arg(args, size_t *);
1267                                 *ip = (str - buf);
1268                         } else {
1269                                 int *ip = va_arg(args, int *);
1270                                 *ip = (str - buf);
1271                         }
1272                         break;
1273                 }
1274
1275                 default:
1276                         switch (spec.type) {
1277                         case FORMAT_TYPE_LONG_LONG:
1278                                 num = va_arg(args, long long);
1279                                 break;
1280                         case FORMAT_TYPE_ULONG:
1281                                 num = va_arg(args, unsigned long);
1282                                 break;
1283                         case FORMAT_TYPE_LONG:
1284                                 num = va_arg(args, long);
1285                                 break;
1286                         case FORMAT_TYPE_SIZE_T:
1287                                 num = va_arg(args, size_t);
1288                                 break;
1289                         case FORMAT_TYPE_PTRDIFF:
1290                                 num = va_arg(args, ptrdiff_t);
1291                                 break;
1292                         case FORMAT_TYPE_UBYTE:
1293                                 num = (unsigned char) va_arg(args, int);
1294                                 break;
1295                         case FORMAT_TYPE_BYTE:
1296                                 num = (signed char) va_arg(args, int);
1297                                 break;
1298                         case FORMAT_TYPE_USHORT:
1299                                 num = (unsigned short) va_arg(args, int);
1300                                 break;
1301                         case FORMAT_TYPE_SHORT:
1302                                 num = (short) va_arg(args, int);
1303                                 break;
1304                         case FORMAT_TYPE_INT:
1305                                 num = (int) va_arg(args, int);
1306                                 break;
1307                         default:
1308                                 num = va_arg(args, unsigned int);
1309                         }
1310
1311                         str = number(str, end, num, spec);
1312                 }
1313         }
1314
1315         if (size > 0) {
1316                 if (str < end)
1317                         *str = '\0';
1318                 else
1319                         end[-1] = '\0';
1320         }
1321
1322         /* the trailing null byte doesn't count towards the total */
1323         return str-buf;
1324
1325 }
1326 EXPORT_SYMBOL(vsnprintf);
1327
1328 /**
1329  * vscnprintf - Format a string and place it in a buffer
1330  * @buf: The buffer to place the result into
1331  * @size: The size of the buffer, including the trailing null space
1332  * @fmt: The format string to use
1333  * @args: Arguments for the format string
1334  *
1335  * The return value is the number of characters which have been written into
1336  * the @buf not including the trailing '\0'. If @size is == 0 the function
1337  * returns 0.
1338  *
1339  * Call this function if you are already dealing with a va_list.
1340  * You probably want scnprintf() instead.
1341  *
1342  * See the vsnprintf() documentation for format string extensions over C99.
1343  */
1344 int vscnprintf(char *buf, size_t size, const char *fmt, va_list args)
1345 {
1346         int i;
1347
1348         i = vsnprintf(buf, size, fmt, args);
1349
1350         if (likely(i < size))
1351                 return i;
1352         if (size != 0)
1353                 return size - 1;
1354         return 0;
1355 }
1356 EXPORT_SYMBOL(vscnprintf);
1357
1358 /**
1359  * snprintf - Format a string and place it in a buffer
1360  * @buf: The buffer to place the result into
1361  * @size: The size of the buffer, including the trailing null space
1362  * @fmt: The format string to use
1363  * @...: Arguments for the format string
1364  *
1365  * The return value is the number of characters which would be
1366  * generated for the given input, excluding the trailing null,
1367  * as per ISO C99.  If the return is greater than or equal to
1368  * @size, the resulting string is truncated.
1369  *
1370  * See the vsnprintf() documentation for format string extensions over C99.
1371  */
1372 int snprintf(char *buf, size_t size, const char *fmt, ...)
1373 {
1374         va_list args;
1375         int i;
1376
1377         va_start(args, fmt);
1378         i = vsnprintf(buf, size, fmt, args);
1379         va_end(args);
1380
1381         return i;
1382 }
1383 EXPORT_SYMBOL(snprintf);
1384
1385 /**
1386  * scnprintf - Format a string and place it in a buffer
1387  * @buf: The buffer to place the result into
1388  * @size: The size of the buffer, including the trailing null space
1389  * @fmt: The format string to use
1390  * @...: Arguments for the format string
1391  *
1392  * The return value is the number of characters written into @buf not including
1393  * the trailing '\0'. If @size is == 0 the function returns 0.
1394  */
1395
1396 int scnprintf(char *buf, size_t size, const char *fmt, ...)
1397 {
1398         va_list args;
1399         int i;
1400
1401         va_start(args, fmt);
1402         i = vscnprintf(buf, size, fmt, args);
1403         va_end(args);
1404
1405         return i;
1406 }
1407 EXPORT_SYMBOL(scnprintf);
1408
1409 /**
1410  * vsprintf - Format a string and place it in a buffer
1411  * @buf: The buffer to place the result into
1412  * @fmt: The format string to use
1413  * @args: Arguments for the format string
1414  *
1415  * The function returns the number of characters written
1416  * into @buf. Use vsnprintf() or vscnprintf() in order to avoid
1417  * buffer overflows.
1418  *
1419  * Call this function if you are already dealing with a va_list.
1420  * You probably want sprintf() instead.
1421  *
1422  * See the vsnprintf() documentation for format string extensions over C99.
1423  */
1424 int vsprintf(char *buf, const char *fmt, va_list args)
1425 {
1426         return vsnprintf(buf, INT_MAX, fmt, args);
1427 }
1428 EXPORT_SYMBOL(vsprintf);
1429
1430 /**
1431  * sprintf - Format a string and place it in a buffer
1432  * @buf: The buffer to place the result into
1433  * @fmt: The format string to use
1434  * @...: Arguments for the format string
1435  *
1436  * The function returns the number of characters written
1437  * into @buf. Use snprintf() or scnprintf() in order to avoid
1438  * buffer overflows.
1439  *
1440  * See the vsnprintf() documentation for format string extensions over C99.
1441  */
1442 int sprintf(char *buf, const char *fmt, ...)
1443 {
1444         va_list args;
1445         int i;
1446
1447         va_start(args, fmt);
1448         i = vsnprintf(buf, INT_MAX, fmt, args);
1449         va_end(args);
1450
1451         return i;
1452 }
1453 EXPORT_SYMBOL(sprintf);
1454
1455 #ifdef CONFIG_BINARY_PRINTF
1456 /*
1457  * bprintf service:
1458  * vbin_printf() - VA arguments to binary data
1459  * bstr_printf() - Binary data to text string
1460  */
1461
1462 /**
1463  * vbin_printf - Parse a format string and place args' binary value in a buffer
1464  * @bin_buf: The buffer to place args' binary value
1465  * @size: The size of the buffer(by words(32bits), not characters)
1466  * @fmt: The format string to use
1467  * @args: Arguments for the format string
1468  *
1469  * The format follows C99 vsnprintf, except %n is ignored, and its argument
1470  * is skiped.
1471  *
1472  * The return value is the number of words(32bits) which would be generated for
1473  * the given input.
1474  *
1475  * NOTE:
1476  * If the return value is greater than @size, the resulting bin_buf is NOT
1477  * valid for bstr_printf().
1478  */
1479 int vbin_printf(u32 *bin_buf, size_t size, const char *fmt, va_list args)
1480 {
1481         struct printf_spec spec = {0};
1482         char *str, *end;
1483
1484         str = (char *)bin_buf;
1485         end = (char *)(bin_buf + size);
1486
1487 #define save_arg(type)                                                  \
1488 do {                                                                    \
1489         if (sizeof(type) == 8) {                                        \
1490                 unsigned long long value;                               \
1491                 str = PTR_ALIGN(str, sizeof(u32));                      \
1492                 value = va_arg(args, unsigned long long);               \
1493                 if (str + sizeof(type) <= end) {                        \
1494                         *(u32 *)str = *(u32 *)&value;                   \
1495                         *(u32 *)(str + 4) = *((u32 *)&value + 1);       \
1496                 }                                                       \
1497         } else {                                                        \
1498                 unsigned long value;                                    \
1499                 str = PTR_ALIGN(str, sizeof(type));                     \
1500                 value = va_arg(args, int);                              \
1501                 if (str + sizeof(type) <= end)                          \
1502                         *(typeof(type) *)str = (type)value;             \
1503         }                                                               \
1504         str += sizeof(type);                                            \
1505 } while (0)
1506
1507         while (*fmt) {
1508                 int read = format_decode(fmt, &spec);
1509
1510                 fmt += read;
1511
1512                 switch (spec.type) {
1513                 case FORMAT_TYPE_NONE:
1514                 case FORMAT_TYPE_INVALID:
1515                 case FORMAT_TYPE_PERCENT_CHAR:
1516                         break;
1517
1518                 case FORMAT_TYPE_WIDTH:
1519                 case FORMAT_TYPE_PRECISION:
1520                         save_arg(int);
1521                         break;
1522
1523                 case FORMAT_TYPE_CHAR:
1524                         save_arg(char);
1525                         break;
1526
1527                 case FORMAT_TYPE_STR: {
1528                         const char *save_str = va_arg(args, char *);
1529                         size_t len;
1530
1531                         if ((unsigned long)save_str > (unsigned long)-PAGE_SIZE
1532                                         || (unsigned long)save_str < PAGE_SIZE)
1533                                 save_str = "(null)";
1534                         len = strlen(save_str) + 1;
1535                         if (str + len < end)
1536                                 memcpy(str, save_str, len);
1537                         str += len;
1538                         break;
1539                 }
1540
1541                 case FORMAT_TYPE_PTR:
1542                         save_arg(void *);
1543                         /* skip all alphanumeric pointer suffixes */
1544                         while (isalnum(*fmt))
1545                                 fmt++;
1546                         break;
1547
1548                 case FORMAT_TYPE_NRCHARS: {
1549                         /* skip %n 's argument */
1550                         u8 qualifier = spec.qualifier;
1551                         void *skip_arg;
1552                         if (qualifier == 'l')
1553                                 skip_arg = va_arg(args, long *);
1554                         else if (TOLOWER(qualifier) == 'z')
1555                                 skip_arg = va_arg(args, size_t *);
1556                         else
1557                                 skip_arg = va_arg(args, int *);
1558                         break;
1559                 }
1560
1561                 default:
1562                         switch (spec.type) {
1563
1564                         case FORMAT_TYPE_LONG_LONG:
1565                                 save_arg(long long);
1566                                 break;
1567                         case FORMAT_TYPE_ULONG:
1568                         case FORMAT_TYPE_LONG:
1569                                 save_arg(unsigned long);
1570                                 break;
1571                         case FORMAT_TYPE_SIZE_T:
1572                                 save_arg(size_t);
1573                                 break;
1574                         case FORMAT_TYPE_PTRDIFF:
1575                                 save_arg(ptrdiff_t);
1576                                 break;
1577                         case FORMAT_TYPE_UBYTE:
1578                         case FORMAT_TYPE_BYTE:
1579                                 save_arg(char);
1580                                 break;
1581                         case FORMAT_TYPE_USHORT:
1582                         case FORMAT_TYPE_SHORT:
1583                                 save_arg(short);
1584                                 break;
1585                         default:
1586                                 save_arg(int);
1587                         }
1588                 }
1589         }
1590
1591         return (u32 *)(PTR_ALIGN(str, sizeof(u32))) - bin_buf;
1592 #undef save_arg
1593 }
1594 EXPORT_SYMBOL_GPL(vbin_printf);
1595
1596 /**
1597  * bstr_printf - Format a string from binary arguments and place it in a buffer
1598  * @buf: The buffer to place the result into
1599  * @size: The size of the buffer, including the trailing null space
1600  * @fmt: The format string to use
1601  * @bin_buf: Binary arguments for the format string
1602  *
1603  * This function like C99 vsnprintf, but the difference is that vsnprintf gets
1604  * arguments from stack, and bstr_printf gets arguments from @bin_buf which is
1605  * a binary buffer that generated by vbin_printf.
1606  *
1607  * The format follows C99 vsnprintf, but has some extensions:
1608  *  see vsnprintf comment for details.
1609  *
1610  * The return value is the number of characters which would
1611  * be generated for the given input, excluding the trailing
1612  * '\0', as per ISO C99. If you want to have the exact
1613  * number of characters written into @buf as return value
1614  * (not including the trailing '\0'), use vscnprintf(). If the
1615  * return is greater than or equal to @size, the resulting
1616  * string is truncated.
1617  */
1618 int bstr_printf(char *buf, size_t size, const char *fmt, const u32 *bin_buf)
1619 {
1620         struct printf_spec spec = {0};
1621         char *str, *end;
1622         const char *args = (const char *)bin_buf;
1623
1624         if (WARN_ON_ONCE((int) size < 0))
1625                 return 0;
1626
1627         str = buf;
1628         end = buf + size;
1629
1630 #define get_arg(type)                                                   \
1631 ({                                                                      \
1632         typeof(type) value;                                             \
1633         if (sizeof(type) == 8) {                                        \
1634                 args = PTR_ALIGN(args, sizeof(u32));                    \
1635                 *(u32 *)&value = *(u32 *)args;                          \
1636                 *((u32 *)&value + 1) = *(u32 *)(args + 4);              \
1637         } else {                                                        \
1638                 args = PTR_ALIGN(args, sizeof(type));                   \
1639                 value = *(typeof(type) *)args;                          \
1640         }                                                               \
1641         args += sizeof(type);                                           \
1642         value;                                                          \
1643 })
1644
1645         /* Make sure end is always >= buf */
1646         if (end < buf) {
1647                 end = ((void *)-1);
1648                 size = end - buf;
1649         }
1650
1651         while (*fmt) {
1652                 const char *old_fmt = fmt;
1653                 int read = format_decode(fmt, &spec);
1654
1655                 fmt += read;
1656
1657                 switch (spec.type) {
1658                 case FORMAT_TYPE_NONE: {
1659                         int copy = read;
1660                         if (str < end) {
1661                                 if (copy > end - str)
1662                                         copy = end - str;
1663                                 memcpy(str, old_fmt, copy);
1664                         }
1665                         str += read;
1666                         break;
1667                 }
1668
1669                 case FORMAT_TYPE_WIDTH:
1670                         spec.field_width = get_arg(int);
1671                         break;
1672
1673                 case FORMAT_TYPE_PRECISION:
1674                         spec.precision = get_arg(int);
1675                         break;
1676
1677                 case FORMAT_TYPE_CHAR: {
1678                         char c;
1679
1680                         if (!(spec.flags & LEFT)) {
1681                                 while (--spec.field_width > 0) {
1682                                         if (str < end)
1683                                                 *str = ' ';
1684                                         ++str;
1685                                 }
1686                         }
1687                         c = (unsigned char) get_arg(char);
1688                         if (str < end)
1689                                 *str = c;
1690                         ++str;
1691                         while (--spec.field_width > 0) {
1692                                 if (str < end)
1693                                         *str = ' ';
1694                                 ++str;
1695                         }
1696                         break;
1697                 }
1698
1699                 case FORMAT_TYPE_STR: {
1700                         const char *str_arg = args;
1701                         args += strlen(str_arg) + 1;
1702                         str = string(str, end, (char *)str_arg, spec);
1703                         break;
1704                 }
1705
1706                 case FORMAT_TYPE_PTR:
1707                         str = pointer(fmt+1, str, end, get_arg(void *), spec);
1708                         while (isalnum(*fmt))
1709                                 fmt++;
1710                         break;
1711
1712                 case FORMAT_TYPE_PERCENT_CHAR:
1713                 case FORMAT_TYPE_INVALID:
1714                         if (str < end)
1715                                 *str = '%';
1716                         ++str;
1717                         break;
1718
1719                 case FORMAT_TYPE_NRCHARS:
1720                         /* skip */
1721                         break;
1722
1723                 default: {
1724                         unsigned long long num;
1725
1726                         switch (spec.type) {
1727
1728                         case FORMAT_TYPE_LONG_LONG:
1729                                 num = get_arg(long long);
1730                                 break;
1731                         case FORMAT_TYPE_ULONG:
1732                         case FORMAT_TYPE_LONG:
1733                                 num = get_arg(unsigned long);
1734                                 break;
1735                         case FORMAT_TYPE_SIZE_T:
1736                                 num = get_arg(size_t);
1737                                 break;
1738                         case FORMAT_TYPE_PTRDIFF:
1739                                 num = get_arg(ptrdiff_t);
1740                                 break;
1741                         case FORMAT_TYPE_UBYTE:
1742                                 num = get_arg(unsigned char);
1743                                 break;
1744                         case FORMAT_TYPE_BYTE:
1745                                 num = get_arg(signed char);
1746                                 break;
1747                         case FORMAT_TYPE_USHORT:
1748                                 num = get_arg(unsigned short);
1749                                 break;
1750                         case FORMAT_TYPE_SHORT:
1751                                 num = get_arg(short);
1752                                 break;
1753                         case FORMAT_TYPE_UINT:
1754                                 num = get_arg(unsigned int);
1755                                 break;
1756                         default:
1757                                 num = get_arg(int);
1758                         }
1759
1760                         str = number(str, end, num, spec);
1761                 } /* default: */
1762                 } /* switch(spec.type) */
1763         } /* while(*fmt) */
1764
1765         if (size > 0) {
1766                 if (str < end)
1767                         *str = '\0';
1768                 else
1769                         end[-1] = '\0';
1770         }
1771
1772 #undef get_arg
1773
1774         /* the trailing null byte doesn't count towards the total */
1775         return str - buf;
1776 }
1777 EXPORT_SYMBOL_GPL(bstr_printf);
1778
1779 /**
1780  * bprintf - Parse a format string and place args' binary value in a buffer
1781  * @bin_buf: The buffer to place args' binary value
1782  * @size: The size of the buffer(by words(32bits), not characters)
1783  * @fmt: The format string to use
1784  * @...: Arguments for the format string
1785  *
1786  * The function returns the number of words(u32) written
1787  * into @bin_buf.
1788  */
1789 int bprintf(u32 *bin_buf, size_t size, const char *fmt, ...)
1790 {
1791         va_list args;
1792         int ret;
1793
1794         va_start(args, fmt);
1795         ret = vbin_printf(bin_buf, size, fmt, args);
1796         va_end(args);
1797
1798         return ret;
1799 }
1800 EXPORT_SYMBOL_GPL(bprintf);
1801
1802 #endif /* CONFIG_BINARY_PRINTF */
1803
1804 /**
1805  * vsscanf - Unformat a buffer into a list of arguments
1806  * @buf:        input buffer
1807  * @fmt:        format of buffer
1808  * @args:       arguments
1809  */
1810 int vsscanf(const char *buf, const char *fmt, va_list args)
1811 {
1812         const char *str = buf;
1813         char *next;
1814         char digit;
1815         int num = 0;
1816         u8 qualifier;
1817         u8 base;
1818         s16 field_width;
1819         bool is_sign;
1820
1821         while (*fmt && *str) {
1822                 /* skip any white space in format */
1823                 /* white space in format matchs any amount of
1824                  * white space, including none, in the input.
1825                  */
1826                 if (isspace(*fmt)) {
1827                         fmt = skip_spaces(++fmt);
1828                         str = skip_spaces(str);
1829                 }
1830
1831                 /* anything that is not a conversion must match exactly */
1832                 if (*fmt != '%' && *fmt) {
1833                         if (*fmt++ != *str++)
1834                                 break;
1835                         continue;
1836                 }
1837
1838                 if (!*fmt)
1839                         break;
1840                 ++fmt;
1841
1842                 /* skip this conversion.
1843                  * advance both strings to next white space
1844                  */
1845                 if (*fmt == '*') {
1846                         while (!isspace(*fmt) && *fmt != '%' && *fmt)
1847                                 fmt++;
1848                         while (!isspace(*str) && *str)
1849                                 str++;
1850                         continue;
1851                 }
1852
1853                 /* get field width */
1854                 field_width = -1;
1855                 if (isdigit(*fmt))
1856                         field_width = skip_atoi(&fmt);
1857
1858                 /* get conversion qualifier */
1859                 qualifier = -1;
1860                 if (*fmt == 'h' || TOLOWER(*fmt) == 'l' ||
1861                     TOLOWER(*fmt) == 'z') {
1862                         qualifier = *fmt++;
1863                         if (unlikely(qualifier == *fmt)) {
1864                                 if (qualifier == 'h') {
1865                                         qualifier = 'H';
1866                                         fmt++;
1867                                 } else if (qualifier == 'l') {
1868                                         qualifier = 'L';
1869                                         fmt++;
1870                                 }
1871                         }
1872                 }
1873
1874                 if (!*fmt || !*str)
1875                         break;
1876
1877                 base = 10;
1878                 is_sign = 0;
1879
1880                 switch (*fmt++) {
1881                 case 'c':
1882                 {
1883                         char *s = (char *)va_arg(args, char*);
1884                         if (field_width == -1)
1885                                 field_width = 1;
1886                         do {
1887                                 *s++ = *str++;
1888                         } while (--field_width > 0 && *str);
1889                         num++;
1890                 }
1891                 continue;
1892                 case 's':
1893                 {
1894                         char *s = (char *)va_arg(args, char *);
1895                         if (field_width == -1)
1896                                 field_width = SHRT_MAX;
1897                         /* first, skip leading white space in buffer */
1898                         str = skip_spaces(str);
1899
1900                         /* now copy until next white space */
1901                         while (*str && !isspace(*str) && field_width--)
1902                                 *s++ = *str++;
1903                         *s = '\0';
1904                         num++;
1905                 }
1906                 continue;
1907                 case 'n':
1908                         /* return number of characters read so far */
1909                 {
1910                         int *i = (int *)va_arg(args, int*);
1911                         *i = str - buf;
1912                 }
1913                 continue;
1914                 case 'o':
1915                         base = 8;
1916                         break;
1917                 case 'x':
1918                 case 'X':
1919                         base = 16;
1920                         break;
1921                 case 'i':
1922                         base = 0;
1923                 case 'd':
1924                         is_sign = 1;
1925                 case 'u':
1926                         break;
1927                 case '%':
1928                         /* looking for '%' in str */
1929                         if (*str++ != '%')
1930                                 return num;
1931                         continue;
1932                 default:
1933                         /* invalid format; stop here */
1934                         return num;
1935                 }
1936
1937                 /* have some sort of integer conversion.
1938                  * first, skip white space in buffer.
1939                  */
1940                 str = skip_spaces(str);
1941
1942                 digit = *str;
1943                 if (is_sign && digit == '-')
1944                         digit = *(str + 1);
1945
1946                 if (!digit
1947                     || (base == 16 && !isxdigit(digit))
1948                     || (base == 10 && !isdigit(digit))
1949                     || (base == 8 && (!isdigit(digit) || digit > '7'))
1950                     || (base == 0 && !isdigit(digit)))
1951                         break;
1952
1953                 switch (qualifier) {
1954                 case 'H':       /* that's 'hh' in format */
1955                         if (is_sign) {
1956                                 signed char *s = (signed char *)va_arg(args, signed char *);
1957                                 *s = (signed char)simple_strtol(str, &next, base);
1958                         } else {
1959                                 unsigned char *s = (unsigned char *)va_arg(args, unsigned char *);
1960                                 *s = (unsigned char)simple_strtoul(str, &next, base);
1961                         }
1962                         break;
1963                 case 'h':
1964                         if (is_sign) {
1965                                 short *s = (short *)va_arg(args, short *);
1966                                 *s = (short)simple_strtol(str, &next, base);
1967                         } else {
1968                                 unsigned short *s = (unsigned short *)va_arg(args, unsigned short *);
1969                                 *s = (unsigned short)simple_strtoul(str, &next, base);
1970                         }
1971                         break;
1972                 case 'l':
1973                         if (is_sign) {
1974                                 long *l = (long *)va_arg(args, long *);
1975                                 *l = simple_strtol(str, &next, base);
1976                         } else {
1977                                 unsigned long *l = (unsigned long *)va_arg(args, unsigned long *);
1978                                 *l = simple_strtoul(str, &next, base);
1979                         }
1980                         break;
1981                 case 'L':
1982                         if (is_sign) {
1983                                 long long *l = (long long *)va_arg(args, long long *);
1984                                 *l = simple_strtoll(str, &next, base);
1985                         } else {
1986                                 unsigned long long *l = (unsigned long long *)va_arg(args, unsigned long long *);
1987                                 *l = simple_strtoull(str, &next, base);
1988                         }
1989                         break;
1990                 case 'Z':
1991                 case 'z':
1992                 {
1993                         size_t *s = (size_t *)va_arg(args, size_t *);
1994                         *s = (size_t)simple_strtoul(str, &next, base);
1995                 }
1996                 break;
1997                 default:
1998                         if (is_sign) {
1999                                 int *i = (int *)va_arg(args, int *);
2000                                 *i = (int)simple_strtol(str, &next, base);
2001                         } else {
2002                                 unsigned int *i = (unsigned int *)va_arg(args, unsigned int*);
2003                                 *i = (unsigned int)simple_strtoul(str, &next, base);
2004                         }
2005                         break;
2006                 }
2007                 num++;
2008
2009                 if (!next)
2010                         break;
2011                 str = next;
2012         }
2013
2014         /*
2015          * Now we've come all the way through so either the input string or the
2016          * format ended. In the former case, there can be a %n at the current
2017          * position in the format that needs to be filled.
2018          */
2019         if (*fmt == '%' && *(fmt + 1) == 'n') {
2020                 int *p = (int *)va_arg(args, int *);
2021                 *p = str - buf;
2022         }
2023
2024         return num;
2025 }
2026 EXPORT_SYMBOL(vsscanf);
2027
2028 /**
2029  * sscanf - Unformat a buffer into a list of arguments
2030  * @buf:        input buffer
2031  * @fmt:        formatting of buffer
2032  * @...:        resulting arguments
2033  */
2034 int sscanf(const char *buf, const char *fmt, ...)
2035 {
2036         va_list args;
2037         int i;
2038
2039         va_start(args, fmt);
2040         i = vsscanf(buf, fmt, args);
2041         va_end(args);
2042
2043         return i;
2044 }
2045 EXPORT_SYMBOL(sscanf);