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 #include "kstrtox.h"
  35
  36 /**
  37  * simple_strtoull - convert a string to an unsigned long long
  38  * @cp: The start of the string
  39  * @endp: A pointer to the end of the parsed string will be placed here
  40  * @base: The number base to use
  41  */
  42 unsigned long long simple_strtoull(const char *cp, char **endp, unsigned int base)
  43 {
  44         unsigned long long result;
  45         unsigned int rv;
  46
  47         cp = _parse_integer_fixup_radix(cp, &base);
  48         rv = _parse_integer(cp, base, &result);
  49         /* FIXME */
  50         cp += (rv & ~KSTRTOX_OVERFLOW);
  51
  52         if (endp)
  53                 *endp = (char *)cp;
  54
  55         return result;
  56 }
  57 EXPORT_SYMBOL(simple_strtoull);
  58
  59 /**
  60  * simple_strtoul - convert a string to an unsigned long
  61  * @cp: The start of the string
  62  * @endp: A pointer to the end of the parsed string will be placed here
  63  * @base: The number base to use
  64  */
  65 unsigned long simple_strtoul(const char *cp, char **endp, unsigned int base)
  66 {
  67         return simple_strtoull(cp, endp, base);
  68 }
  69 EXPORT_SYMBOL(simple_strtoul);
  70
  71 /**
  72  * simple_strtol - convert a string to a signed long
  73  * @cp: The start of the string
  74  * @endp: A pointer to the end of the parsed string will be placed here
  75  * @base: The number base to use
  76  */
  77 long simple_strtol(const char *cp, char **endp, unsigned int base)
  78 {
  79         if (*cp == '-')
  80                 return -simple_strtoul(cp + 1, endp, base);
  81
  82         return simple_strtoul(cp, endp, base);
  83 }
  84 EXPORT_SYMBOL(simple_strtol);
  85
  86 /**
  87  * simple_strtoll - convert a string to a signed long long
  88  * @cp: The start of the string
  89  * @endp: A pointer to the end of the parsed string will be placed here
  90  * @base: The number base to use
  91  */
  92 long long simple_strtoll(const char *cp, char **endp, unsigned int base)
  93 {
  94         if (*cp == '-')
  95                 return -simple_strtoull(cp + 1, endp, base);
  96
  97         return simple_strtoull(cp, endp, base);
  98 }
  99 EXPORT_SYMBOL(simple_strtoll);
 100
 101 static noinline_for_stack
 102 int skip_atoi(const char **s)
 103 {
 104         int i = 0;
 105
 106         while (isdigit(**s))
 107                 i = i*10 + *((*s)++) - '0';
 108
 109         return i;
 110 }
 111
 112 /* Decimal conversion is by far the most typical, and is used
 113  * for /proc and /sys data. This directly impacts e.g. top performance
 114  * with many processes running. We optimize it for speed
 115  * using code from
 116  * http://www.cs.uiowa.edu/~jones/bcd/decimal.html
 117  * (with permission from the author, Douglas W. Jones). */
 118
 119 /* Formats correctly any integer in [0,99999].
 120  * Outputs from one to five digits depending on input.
 121  * On i386 gcc 4.1.2 -O2: ~250 bytes of code. */
 122 static noinline_for_stack
 123 char *put_dec_trunc(char *buf, unsigned q)
 124 {
 125         unsigned d3, d2, d1, d0;
 126         d1 = (q>>4) & 0xf;
 127         d2 = (q>>8) & 0xf;
 128         d3 = (q>>12);
 129
 130         d0 = 6*(d3 + d2 + d1) + (q & 0xf);
 131         q = (d0 * 0xcd) >> 11;
 132         d0 = d0 - 10*q;
 133         *buf++ = d0 + '0'; /* least significant digit */
 134         d1 = q + 9*d3 + 5*d2 + d1;
 135         if (d1 != 0) {
 136                 q = (d1 * 0xcd) >> 11;
 137                 d1 = d1 - 10*q;
 138                 *buf++ = d1 + '0'; /* next digit */
 139
 140                 d2 = q + 2*d2;
 141                 if ((d2 != 0) || (d3 != 0)) {
 142                         q = (d2 * 0xd) >> 7;
 143                         d2 = d2 - 10*q;
 144                         *buf++ = d2 + '0'; /* next digit */
 145
 146                         d3 = q + 4*d3;
 147                         if (d3 != 0) {
 148                                 q = (d3 * 0xcd) >> 11;
 149                                 d3 = d3 - 10*q;
 150                                 *buf++ = d3 + '0';  /* next digit */
 151                                 if (q != 0)
 152                                         *buf++ = q + '0'; /* most sign. digit */
 153                         }
 154                 }
 155         }
 156
 157         return buf;
 158 }
 159 /* Same with if's removed. Always emits five digits */
 160 static noinline_for_stack
 161 char *put_dec_full(char *buf, unsigned q)
 162 {
 163         /* BTW, if q is in [0,9999], 8-bit ints will be enough, */
 164         /* but anyway, gcc produces better code with full-sized ints */
 165         unsigned d3, d2, d1, d0;
 166         d1 = (q>>4) & 0xf;
 167         d2 = (q>>8) & 0xf;
 168         d3 = (q>>12);
 169
 170         /*
 171          * Possible ways to approx. divide by 10
 172          * gcc -O2 replaces multiply with shifts and adds
 173          * (x * 0xcd) >> 11: 11001101 - shorter code than * 0x67 (on i386)
 174          * (x * 0x67) >> 10:  1100111
 175          * (x * 0x34) >> 9:    110100 - same
 176          * (x * 0x1a) >> 8:     11010 - same
 177          * (x * 0x0d) >> 7:      1101 - same, shortest code (on i386)
 178          */
 179         d0 = 6*(d3 + d2 + d1) + (q & 0xf);
 180         q = (d0 * 0xcd) >> 11;
 181         d0 = d0 - 10*q;
 182         *buf++ = d0 + '0';
 183         d1 = q + 9*d3 + 5*d2 + d1;
 184                 q = (d1 * 0xcd) >> 11;
 185                 d1 = d1 - 10*q;
 186                 *buf++ = d1 + '0';
 187
 188                 d2 = q + 2*d2;
 189                         q = (d2 * 0xd) >> 7;
 190                         d2 = d2 - 10*q;
 191                         *buf++ = d2 + '0';
 192
 193                         d3 = q + 4*d3;
 194                                 q = (d3 * 0xcd) >> 11; /* - shorter code */
 195                                 /* q = (d3 * 0x67) >> 10; - would also work */
 196                                 d3 = d3 - 10*q;
 197                                 *buf++ = d3 + '0';
 198                                         *buf++ = q + '0';
 199
 200         return buf;
 201 }
 202 /* No inlining helps gcc to use registers better */
 203 static noinline_for_stack
 204 char *put_dec(char *buf, unsigned long long num)
 205 {
 206         while (1) {
 207                 unsigned rem;
 208                 if (num < 100000)
 209                         return put_dec_trunc(buf, num);
 210                 rem = do_div(num, 100000);
 211                 buf = put_dec_full(buf, rem);
 212         }
 213 }
 214
 215 #define ZEROPAD 1               /* pad with zero */
 216 #define SIGN    2               /* unsigned/signed long */
 217 #define PLUS    4               /* show plus */
 218 #define SPACE   8               /* space if plus */
 219 #define LEFT    16              /* left justified */
 220 #define SMALL   32              /* use lowercase in hex (must be 32 == 0x20) */
 221 #define SPECIAL 64              /* prefix hex with "0x", octal with "0" */
 222
 223 enum format_type {
 224         FORMAT_TYPE_NONE, /* Just a string part */
 225         FORMAT_TYPE_WIDTH,
 226         FORMAT_TYPE_PRECISION,
 227         FORMAT_TYPE_CHAR,
 228         FORMAT_TYPE_STR,
 229         FORMAT_TYPE_PTR,
 230         FORMAT_TYPE_PERCENT_CHAR,
 231         FORMAT_TYPE_INVALID,
 232         FORMAT_TYPE_LONG_LONG,
 233         FORMAT_TYPE_ULONG,
 234         FORMAT_TYPE_LONG,
 235         FORMAT_TYPE_UBYTE,
 236         FORMAT_TYPE_BYTE,
 237         FORMAT_TYPE_USHORT,
 238         FORMAT_TYPE_SHORT,
 239         FORMAT_TYPE_UINT,
 240         FORMAT_TYPE_INT,
 241         FORMAT_TYPE_NRCHARS,
 242         FORMAT_TYPE_SIZE_T,
 243         FORMAT_TYPE_PTRDIFF
 244 };
 245
 246 struct printf_spec {
 247         u8      type;           /* format_type enum */
 248         u8      flags;          /* flags to number() */
 249         u8      base;           /* number base, 8, 10 or 16 only */
 250         u8      qualifier;      /* number qualifier, one of 'hHlLtzZ' */
 251         s16     field_width;    /* width of output field */
 252         s16     precision;      /* # of digits/chars */
 253 };
 254
 255 static noinline_for_stack
 256 char *number(char *buf, char *end, unsigned long long num,
 257              struct printf_spec spec)
 258 {
 259         /* we are called with base 8, 10 or 16, only, thus don't need "G..."  */
 260         static const char digits[16] = "0123456789ABCDEF"; /* "GHIJKLMNOPQRSTUVWXYZ"; */
 261
 262         char tmp[66];
 263         char sign;
 264         char locase;
 265         int need_pfx = ((spec.flags & SPECIAL) && spec.base != 10);
 266         int i;
 267
 268         /* locase = 0 or 0x20. ORing digits or letters with 'locase'
 269          * produces same digits or (maybe lowercased) letters */
 270         locase = (spec.flags & SMALL);
 271         if (spec.flags & LEFT)
 272                 spec.flags &= ~ZEROPAD;
 273         sign = 0;
 274         if (spec.flags & SIGN) {
 275                 if ((signed long long)num < 0) {
 276                         sign = '-';
 277                         num = -(signed long long)num;
 278                         spec.field_width--;
 279                 } else if (spec.flags & PLUS) {
 280                         sign = '+';
 281                         spec.field_width--;
 282                 } else if (spec.flags & SPACE) {
 283                         sign = ' ';
 284                         spec.field_width--;
 285                 }
 286         }
 287         if (need_pfx) {
 288                 spec.field_width--;
 289                 if (spec.base == 16)
 290                         spec.field_width--;
 291         }
 292
 293         /* generate full string in tmp[], in reverse order */
 294         i = 0;
 295         if (num == 0)
 296                 tmp[i++] = '0';
 297         /* Generic code, for any base:
 298         else do {
 299                 tmp[i++] = (digits[do_div(num,base)] | locase);
 300         } while (num != 0);
 301         */
 302         else if (spec.base != 10) { /* 8 or 16 */
 303                 int mask = spec.base - 1;
 304                 int shift = 3;
 305
 306                 if (spec.base == 16)
 307                         shift = 4;
 308                 do {
 309                         tmp[i++] = (digits[((unsigned char)num) & mask] | locase);
 310                         num >>= shift;
 311                 } while (num);
 312         } else { /* base 10 */
 313                 i = put_dec(tmp, num) - tmp;
 314         }
 315
 316         /* printing 100 using %2d gives "100", not "00" */
 317         if (i > spec.precision)
 318                 spec.precision = i;
 319         /* leading space padding */
 320         spec.field_width -= spec.precision;
 321         if (!(spec.flags & (ZEROPAD+LEFT))) {
 322                 while (--spec.field_width >= 0) {
 323                         if (buf < end)
 324                                 *buf = ' ';
 325                         ++buf;
 326                 }
 327         }
 328         /* sign */
 329         if (sign) {
 330                 if (buf < end)
 331                         *buf = sign;
 332                 ++buf;
 333         }
 334         /* "0x" / "0" prefix */
 335         if (need_pfx) {
 336                 if (buf < end)
 337                         *buf = '0';
 338                 ++buf;
 339                 if (spec.base == 16) {
 340                         if (buf < end)
 341                                 *buf = ('X' | locase);
 342                         ++buf;
 343                 }
 344         }
 345         /* zero or space padding */
 346         if (!(spec.flags & LEFT)) {
 347                 char c = (spec.flags & ZEROPAD) ? '0' : ' ';
 348                 while (--spec.field_width >= 0) {
 349                         if (buf < end)
 350                                 *buf = c;
 351                         ++buf;
 352                 }
 353         }
 354         /* hmm even more zero padding? */
 355         while (i <= --spec.precision) {
 356                 if (buf < end)
 357                         *buf = '0';
 358                 ++buf;
 359         }
 360         /* actual digits of result */
 361         while (--i >= 0) {
 362                 if (buf < end)
 363                         *buf = tmp[i];
 364                 ++buf;
 365         }
 366         /* trailing space padding */
 367         while (--spec.field_width >= 0) {
 368                 if (buf < end)
 369                         *buf = ' ';
 370                 ++buf;
 371         }
 372
 373         return buf;
 374 }
 375
 376 static noinline_for_stack
 377 char *string(char *buf, char *end, const char *s, struct printf_spec spec)
 378 {
 379         int len, i;
 380
 381         if ((unsigned long)s < PAGE_SIZE)
 382                 s = "(null)";
 383
 384         len = strnlen(s, spec.precision);
 385
 386         if (!(spec.flags & LEFT)) {
 387                 while (len < spec.field_width--) {
 388                         if (buf < end)
 389                                 *buf = ' ';
 390                         ++buf;
 391                 }
 392         }
 393         for (i = 0; i < len; ++i) {
 394                 if (buf < end)
 395                         *buf = *s;
 396                 ++buf; ++s;
 397         }
 398         while (len < spec.field_width--) {
 399                 if (buf < end)
 400                         *buf = ' ';
 401                 ++buf;
 402         }
 403
 404         return buf;
 405 }
 406
 407 static noinline_for_stack
 408 char *symbol_string(char *buf, char *end, void *ptr,
 409                     struct printf_spec spec, char ext)
 410 {
 411         unsigned long value = (unsigned long) ptr;
 412 #ifdef CONFIG_KALLSYMS
 413         char sym[KSYM_SYMBOL_LEN];
 414         if (ext == 'B')
 415                 sprint_backtrace(sym, value);
 416         else if (ext != 'f' && ext != 's')
 417                 sprint_symbol(sym, value);
 418         else
 419                 kallsyms_lookup(value, NULL, NULL, NULL, sym);
 420
 421         return string(buf, end, sym, spec);
 422 #else
 423         spec.field_width = 2 * sizeof(void *);
 424         spec.flags |= SPECIAL | SMALL | ZEROPAD;
 425         spec.base = 16;
 426
 427         return number(buf, end, value, spec);
 428 #endif
 429 }
 430
 431 static noinline_for_stack
 432 char *resource_string(char *buf, char *end, struct resource *res,
 433                       struct printf_spec spec, const char *fmt)
 434 {
 435 #ifndef IO_RSRC_PRINTK_SIZE
 436 #define IO_RSRC_PRINTK_SIZE     6
 437 #endif
 438
 439 #ifndef MEM_RSRC_PRINTK_SIZE
 440 #define MEM_RSRC_PRINTK_SIZE    10
 441 #endif
 442         static const struct printf_spec io_spec = {
 443                 .base = 16,
 444                 .field_width = IO_RSRC_PRINTK_SIZE,
 445                 .precision = -1,
 446                 .flags = SPECIAL | SMALL | ZEROPAD,
 447         };
 448         static const struct printf_spec mem_spec = {
 449                 .base = 16,
 450                 .field_width = MEM_RSRC_PRINTK_SIZE,
 451                 .precision = -1,
 452                 .flags = SPECIAL | SMALL | ZEROPAD,
 453         };
 454         static const struct printf_spec bus_spec = {
 455                 .base = 16,
 456                 .field_width = 2,
 457                 .precision = -1,
 458                 .flags = SMALL | ZEROPAD,
 459         };
 460         static const struct printf_spec dec_spec = {
 461                 .base = 10,
 462                 .precision = -1,
 463                 .flags = 0,
 464         };
 465         static const struct printf_spec str_spec = {
 466                 .field_width = -1,
 467                 .precision = 10,
 468                 .flags = LEFT,
 469         };
 470         static const struct printf_spec flag_spec = {
 471                 .base = 16,
 472                 .precision = -1,
 473                 .flags = SPECIAL | SMALL,
 474         };
 475
 476         /* 32-bit res (sizeof==4): 10 chars in dec, 10 in hex ("0x" + 8)
 477          * 64-bit res (sizeof==8): 20 chars in dec, 18 in hex ("0x" + 16) */
 478 #define RSRC_BUF_SIZE           ((2 * sizeof(resource_size_t)) + 4)
 479 #define FLAG_BUF_SIZE           (2 * sizeof(res->flags))
 480 #define DECODED_BUF_SIZE        sizeof("[mem - 64bit pref window disabled]")
 481 #define RAW_BUF_SIZE            sizeof("[mem - flags 0x]")
 482         char sym[max(2*RSRC_BUF_SIZE + DECODED_BUF_SIZE,
 483                      2*RSRC_BUF_SIZE + FLAG_BUF_SIZE + RAW_BUF_SIZE)];
 484
 485         char *p = sym, *pend = sym + sizeof(sym);
 486         int decode = (fmt[0] == 'R') ? 1 : 0;
 487         const struct printf_spec *specp;
 488
 489         *p++ = '[';
 490         if (res->flags & IORESOURCE_IO) {
 491                 p = string(p, pend, "io  ", str_spec);
 492                 specp = &io_spec;
 493         } else if (res->flags & IORESOURCE_MEM) {
 494                 p = string(p, pend, "mem ", str_spec);
 495                 specp = &mem_spec;
 496         } else if (res->flags & IORESOURCE_IRQ) {
 497                 p = string(p, pend, "irq ", str_spec);
 498                 specp = &dec_spec;
 499         } else if (res->flags & IORESOURCE_DMA) {
 500                 p = string(p, pend, "dma ", str_spec);
 501                 specp = &dec_spec;
 502         } else if (res->flags & IORESOURCE_BUS) {
 503                 p = string(p, pend, "bus ", str_spec);
 504                 specp = &bus_spec;
 505         } else {
 506                 p = string(p, pend, "??? ", str_spec);
 507                 specp = &mem_spec;
 508                 decode = 0;
 509         }
 510         p = number(p, pend, res->start, *specp);
 511         if (res->start != res->end) {
 512                 *p++ = '-';
 513                 p = number(p, pend, res->end, *specp);
 514         }
 515         if (decode) {
 516                 if (res->flags & IORESOURCE_MEM_64)
 517                         p = string(p, pend, " 64bit", str_spec);
 518                 if (res->flags & IORESOURCE_PREFETCH)
 519                         p = string(p, pend, " pref", str_spec);
 520                 if (res->flags & IORESOURCE_WINDOW)
 521                         p = string(p, pend, " window", str_spec);
 522                 if (res->flags & IORESOURCE_DISABLED)
 523                         p = string(p, pend, " disabled", str_spec);
 524         } else {
 525                 p = string(p, pend, " flags ", str_spec);
 526                 p = number(p, pend, res->flags, flag_spec);
 527         }
 528         *p++ = ']';
 529         *p = '\0';
 530
 531         return string(buf, end, sym, spec);
 532 }
 533
 534 static noinline_for_stack
 535 char *mac_address_string(char *buf, char *end, u8 *addr,
 536                          struct printf_spec spec, const char *fmt)
 537 {
 538         char mac_addr[sizeof("xx:xx:xx:xx:xx:xx")];
 539         char *p = mac_addr;
 540         int i;
 541         char separator;
 542
 543         if (fmt[1] == 'F') {            /* FDDI canonical format */
 544                 separator = '-';
 545         } else {
 546                 separator = ':';
 547         }
 548
 549         for (i = 0; i < 6; i++) {
 550                 p = hex_byte_pack(p, addr[i]);
 551                 if (fmt[0] == 'M' && i != 5)
 552                         *p++ = separator;
 553         }
 554         *p = '\0';
 555
 556         return string(buf, end, mac_addr, spec);
 557 }
 558
 559 static noinline_for_stack
 560 char *ip4_string(char *p, const u8 *addr, const char *fmt)
 561 {
 562         int i;
 563         bool leading_zeros = (fmt[0] == 'i');
 564         int index;
 565         int step;
 566
 567         switch (fmt[2]) {
 568         case 'h':
 569 #ifdef __BIG_ENDIAN
 570                 index = 0;
 571                 step = 1;
 572 #else
 573                 index = 3;
 574                 step = -1;
 575 #endif
 576                 break;
 577         case 'l':
 578                 index = 3;
 579                 step = -1;
 580                 break;
 581         case 'n':
 582         case 'b':
 583         default:
 584                 index = 0;
 585                 step = 1;
 586                 break;
 587         }
 588         for (i = 0; i < 4; i++) {
 589                 char temp[3];   /* hold each IP quad in reverse order */
 590                 int digits = put_dec_trunc(temp, addr[index]) - temp;
 591                 if (leading_zeros) {
 592                         if (digits < 3)
 593                                 *p++ = '0';
 594                         if (digits < 2)
 595                                 *p++ = '0';
 596                 }
 597                 /* reverse the digits in the quad */
 598                 while (digits--)
 599                         *p++ = temp[digits];
 600                 if (i < 3)
 601                         *p++ = '.';
 602                 index += step;
 603         }
 604         *p = '\0';
 605
 606         return p;
 607 }
 608
 609 static noinline_for_stack
 610 char *ip6_compressed_string(char *p, const char *addr)
 611 {
 612         int i, j, range;
 613         unsigned char zerolength[8];
 614         int longest = 1;
 615         int colonpos = -1;
 616         u16 word;
 617         u8 hi, lo;
 618         bool needcolon = false;
 619         bool useIPv4;
 620         struct in6_addr in6;
 621
 622         memcpy(&in6, addr, sizeof(struct in6_addr));
 623
 624         useIPv4 = ipv6_addr_v4mapped(&in6) || ipv6_addr_is_isatap(&in6);
 625
 626         memset(zerolength, 0, sizeof(zerolength));
 627
 628         if (useIPv4)
 629                 range = 6;
 630         else
 631                 range = 8;
 632
 633         /* find position of longest 0 run */
 634         for (i = 0; i < range; i++) {
 635                 for (j = i; j < range; j++) {
 636                         if (in6.s6_addr16[j] != 0)
 637                                 break;
 638                         zerolength[i]++;
 639                 }
 640         }
 641         for (i = 0; i < range; i++) {
 642                 if (zerolength[i] > longest) {
 643                         longest = zerolength[i];
 644                         colonpos = i;
 645                 }
 646         }
 647         if (longest == 1)               /* don't compress a single 0 */
 648                 colonpos = -1;
 649
 650         /* emit address */
 651         for (i = 0; i < range; i++) {
 652                 if (i == colonpos) {
 653                         if (needcolon || i == 0)
 654                                 *p++ = ':';
 655                         *p++ = ':';
 656                         needcolon = false;
 657                         i += longest - 1;
 658                         continue;
 659                 }
 660                 if (needcolon) {
 661                         *p++ = ':';
 662                         needcolon = false;
 663                 }
 664                 /* hex u16 without leading 0s */
 665                 word = ntohs(in6.s6_addr16[i]);
 666                 hi = word >> 8;
 667                 lo = word & 0xff;
 668                 if (hi) {
 669                         if (hi > 0x0f)
 670                                 p = hex_byte_pack(p, hi);
 671                         else
 672                                 *p++ = hex_asc_lo(hi);
 673                         p = hex_byte_pack(p, lo);
 674                 }
 675                 else if (lo > 0x0f)
 676                         p = hex_byte_pack(p, lo);
 677                 else
 678                         *p++ = hex_asc_lo(lo);
 679                 needcolon = true;
 680         }
 681
 682         if (useIPv4) {
 683                 if (needcolon)
 684                         *p++ = ':';
 685                 p = ip4_string(p, &in6.s6_addr[12], "I4");
 686         }
 687         *p = '\0';
 688
 689         return p;
 690 }
 691
 692 static noinline_for_stack
 693 char *ip6_string(char *p, const char *addr, const char *fmt)
 694 {
 695         int i;
 696
 697         for (i = 0; i < 8; i++) {
 698                 p = hex_byte_pack(p, *addr++);
 699                 p = hex_byte_pack(p, *addr++);
 700                 if (fmt[0] == 'I' && i != 7)
 701                         *p++ = ':';
 702         }
 703         *p = '\0';
 704
 705         return p;
 706 }
 707
 708 static noinline_for_stack
 709 char *ip6_addr_string(char *buf, char *end, const u8 *addr,
 710                       struct printf_spec spec, const char *fmt)
 711 {
 712         char ip6_addr[sizeof("xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:255.255.255.255")];
 713
 714         if (fmt[0] == 'I' && fmt[2] == 'c')
 715                 ip6_compressed_string(ip6_addr, addr);
 716         else
 717                 ip6_string(ip6_addr, addr, fmt);
 718
 719         return string(buf, end, ip6_addr, spec);
 720 }
 721
 722 static noinline_for_stack
 723 char *ip4_addr_string(char *buf, char *end, const u8 *addr,
 724                       struct printf_spec spec, const char *fmt)
 725 {
 726         char ip4_addr[sizeof("255.255.255.255")];
 727
 728         ip4_string(ip4_addr, addr, fmt);
 729
 730         return string(buf, end, ip4_addr, spec);
 731 }
 732
 733 static noinline_for_stack
 734 char *uuid_string(char *buf, char *end, const u8 *addr,
 735                   struct printf_spec spec, const char *fmt)
 736 {
 737         char uuid[sizeof("xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx")];
 738         char *p = uuid;
 739         int i;
 740         static const u8 be[16] = {0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15};
 741         static const u8 le[16] = {3,2,1,0,5,4,7,6,8,9,10,11,12,13,14,15};
 742         const u8 *index = be;
 743         bool uc = false;
 744
 745         switch (*(++fmt)) {
 746         case 'L':
 747                 uc = true;              /* fall-through */
 748         case 'l':
 749                 index = le;
 750                 break;
 751         case 'B':
 752                 uc = true;
 753                 break;
 754         }
 755
 756         for (i = 0; i < 16; i++) {
 757                 p = hex_byte_pack(p, addr[index[i]]);
 758                 switch (i) {
 759                 case 3:
 760                 case 5:
 761                 case 7:
 762                 case 9:
 763                         *p++ = '-';
 764                         break;
 765                 }
 766         }
 767
 768         *p = 0;
 769
 770         if (uc) {
 771                 p = uuid;
 772                 do {
 773                         *p = toupper(*p);
 774                 } while (*(++p));
 775         }
 776
 777         return string(buf, end, uuid, spec);
 778 }
 779
 780 static
 781 char *netdev_feature_string(char *buf, char *end, const u8 *addr,
 782                       struct printf_spec spec)
 783 {
 784         spec.flags |= SPECIAL | SMALL | ZEROPAD;
 785         if (spec.field_width == -1)
 786                 spec.field_width = 2 + 2 * sizeof(netdev_features_t);
 787         spec.base = 16;
 788
 789         return number(buf, end, *(const netdev_features_t *)addr, spec);
 790 }
 791
 792 int kptr_restrict __read_mostly;
 793
 794 /*
 795  * Show a '%p' thing.  A kernel extension is that the '%p' is followed
 796  * by an extra set of alphanumeric characters that are extended format
 797  * specifiers.
 798  *
 799  * Right now we handle:
 800  *
 801  * - 'F' For symbolic function descriptor pointers with offset
 802  * - 'f' For simple symbolic function names without offset
 803  * - 'S' For symbolic direct pointers with offset
 804  * - 's' For symbolic direct pointers without offset
 805  * - 'B' For backtraced symbolic direct pointers with offset
 806  * - 'R' For decoded struct resource, e.g., [mem 0x0-0x1f 64bit pref]
 807  * - 'r' For raw struct resource, e.g., [mem 0x0-0x1f flags 0x201]
 808  * - 'M' For a 6-byte MAC address, it prints the address in the
 809  *       usual colon-separated hex notation
 810  * - 'm' For a 6-byte MAC address, it prints the hex address without colons
 811  * - 'MF' For a 6-byte MAC FDDI address, it prints the address
 812  *       with a dash-separated hex notation
 813  * - 'I' [46] for IPv4/IPv6 addresses printed in the usual way
 814  *       IPv4 uses dot-separated decimal without leading 0's (1.2.3.4)
 815  *       IPv6 uses colon separated network-order 16 bit hex with leading 0's
 816  * - 'i' [46] for 'raw' IPv4/IPv6 addresses
 817  *       IPv6 omits the colons (01020304...0f)
 818  *       IPv4 uses dot-separated decimal with leading 0's (010.123.045.006)
 819  * - '[Ii]4[hnbl]' IPv4 addresses in host, network, big or little endian order
 820  * - 'I6c' for IPv6 addresses printed as specified by
 821  *       http://tools.ietf.org/html/rfc5952
 822  * - 'U' For a 16 byte UUID/GUID, it prints the UUID/GUID in the form
 823  *       "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx"
 824  *       Options for %pU are:
 825  *         b big endian lower case hex (default)
 826  *         B big endian UPPER case hex
 827  *         l little endian lower case hex
 828  *         L little endian UPPER case hex
 829  *           big endian output byte order is:
 830  *             [0][1][2][3]-[4][5]-[6][7]-[8][9]-[10][11][12][13][14][15]
 831  *           little endian output byte order is:
 832  *             [3][2][1][0]-[5][4]-[7][6]-[8][9]-[10][11][12][13][14][15]
 833  * - 'V' For a struct va_format which contains a format string * and va_list *,
 834  *       call vsnprintf(->format, *->va_list).
 835  *       Implements a "recursive vsnprintf".
 836  *       Do not use this feature without some mechanism to verify the
 837  *       correctness of the format string and va_list arguments.
 838  * - 'K' For a kernel pointer that should be hidden from unprivileged users
 839  * - 'NF' For a netdev_features_t
 840  *
 841  * Note: The difference between 'S' and 'F' is that on ia64 and ppc64
 842  * function pointers are really function descriptors, which contain a
 843  * pointer to the real address.
 844  */
 845 static noinline_for_stack
 846 char *pointer(const char *fmt, char *buf, char *end, void *ptr,
 847               struct printf_spec spec)
 848 {
 849         if (!ptr && *fmt != 'K') {
 850                 /*
 851                  * Print (null) with the same width as a pointer so it makes
 852                  * tabular output look nice.
 853                  */
 854                 if (spec.field_width == -1)
 855                         spec.field_width = 2 * sizeof(void *);
 856                 return string(buf, end, "(null)", spec);
 857         }
 858
 859         switch (*fmt) {
 860         case 'F':
 861         case 'f':
 862                 ptr = dereference_function_descriptor(ptr);
 863                 /* Fallthrough */
 864         case 'S':
 865         case 's':
 866         case 'B':
 867                 return symbol_string(buf, end, ptr, spec, *fmt);
 868         case 'R':
 869         case 'r':
 870                 return resource_string(buf, end, ptr, spec, fmt);
 871         case 'M':                       /* Colon separated: 00:01:02:03:04:05 */
 872         case 'm':                       /* Contiguous: 000102030405 */
 873                                         /* [mM]F (FDDI, bit reversed) */
 874                 return mac_address_string(buf, end, ptr, spec, fmt);
 875         case 'I':                       /* Formatted IP supported
 876                                          * 4:   1.2.3.4
 877                                          * 6:   0001:0203:...:0708
 878                                          * 6c:  1::708 or 1::1.2.3.4
 879                                          */
 880         case 'i':                       /* Contiguous:
 881                                          * 4:   001.002.003.004
 882                                          * 6:   000102...0f
 883                                          */
 884                 switch (fmt[1]) {
 885                 case '6':
 886                         return ip6_addr_string(buf, end, ptr, spec, fmt);
 887                 case '4':
 888                         return ip4_addr_string(buf, end, ptr, spec, fmt);
 889                 }
 890                 break;
 891         case 'U':
 892                 return uuid_string(buf, end, ptr, spec, fmt);
 893         case 'V':
 894                 return buf + vsnprintf(buf, end > buf ? end - buf : 0,
 895                                        ((struct va_format *)ptr)->fmt,
 896                                        *(((struct va_format *)ptr)->va));
 897         case 'K':
 898                 /*
 899                  * %pK cannot be used in IRQ context because its test
 900                  * for CAP_SYSLOG would be meaningless.
 901                  */
 902                 if (in_irq() || in_serving_softirq() || in_nmi()) {
 903                         if (spec.field_width == -1)
 904                                 spec.field_width = 2 * sizeof(void *);
 905                         return string(buf, end, "pK-error", spec);
 906                 }
 907                 if (!((kptr_restrict == 0) ||
 908                       (kptr_restrict == 1 &&
 909                        has_capability_noaudit(current, CAP_SYSLOG))))
 910                         ptr = NULL;
 911                 break;
 912         case 'N':
 913                 switch (fmt[1]) {
 914                 case 'F':
 915                         return netdev_feature_string(buf, end, ptr, spec);
 916                 }
 917                 break;
 918         }
 919         spec.flags |= SMALL;
 920         if (spec.field_width == -1) {
 921                 spec.field_width = 2 * sizeof(void *);
 922                 spec.flags |= ZEROPAD;
 923         }
 924         spec.base = 16;
 925
 926         return number(buf, end, (unsigned long) ptr, spec);
 927 }
 928
 929 /*
 930  * Helper function to decode printf style format.
 931  * Each call decode a token from the format and return the
 932  * number of characters read (or likely the delta where it wants
 933  * to go on the next call).
 934  * The decoded token is returned through the parameters
 935  *
 936  * 'h', 'l', or 'L' for integer fields
 937  * 'z' support added 23/7/1999 S.H.
 938  * 'z' changed to 'Z' --davidm 1/25/99
 939  * 't' added for ptrdiff_t
 940  *
 941  * @fmt: the format string
 942  * @type of the token returned
 943  * @flags: various flags such as +, -, # tokens..
 944  * @field_width: overwritten width
 945  * @base: base of the number (octal, hex, ...)
 946  * @precision: precision of a number
 947  * @qualifier: qualifier of a number (long, size_t, ...)
 948  */
 949 static noinline_for_stack
 950 int format_decode(const char *fmt, struct printf_spec *spec)
 951 {
 952         const char *start = fmt;
 953
 954         /* we finished early by reading the field width */
 955         if (spec->type == FORMAT_TYPE_WIDTH) {
 956                 if (spec->field_width < 0) {
 957                         spec->field_width = -spec->field_width;
 958                         spec->flags |= LEFT;
 959                 }
 960                 spec->type = FORMAT_TYPE_NONE;
 961                 goto precision;
 962         }
 963
 964         /* we finished early by reading the precision */
 965         if (spec->type == FORMAT_TYPE_PRECISION) {
 966                 if (spec->precision < 0)
 967                         spec->precision = 0;
 968
 969                 spec->type = FORMAT_TYPE_NONE;
 970                 goto qualifier;
 971         }
 972
 973         /* By default */
 974         spec->type = FORMAT_TYPE_NONE;
 975
 976         for (; *fmt ; ++fmt) {
 977                 if (*fmt == '%')
 978                         break;
 979         }
 980
 981         /* Return the current non-format string */
 982         if (fmt != start || !*fmt)
 983                 return fmt - start;
 984
 985         /* Process flags */
 986         spec->flags = 0;
 987
 988         while (1) { /* this also skips first '%' */
 989                 bool found = true;
 990
 991                 ++fmt;
 992
 993                 switch (*fmt) {
 994                 case '-': spec->flags |= LEFT;    break;
 995                 case '+': spec->flags |= PLUS;    break;
 996                 case ' ': spec->flags |= SPACE;   break;
 997                 case '#': spec->flags |= SPECIAL; break;
 998                 case '0': spec->flags |= ZEROPAD; break;
 999                 default:  found = false;
1000                 }
1001
1002                 if (!found)
1003                         break;
1004         }
1005
1006         /* get field width */
1007         spec->field_width = -1;
1008
1009         if (isdigit(*fmt))
1010                 spec->field_width = skip_atoi(&fmt);
1011         else if (*fmt == '*') {
1012                 /* it's the next argument */
1013                 spec->type = FORMAT_TYPE_WIDTH;
1014                 return ++fmt - start;
1015         }
1016
1017 precision:
1018         /* get the precision */
1019         spec->precision = -1;
1020         if (*fmt == '.') {
1021                 ++fmt;
1022                 if (isdigit(*fmt)) {
1023                         spec->precision = skip_atoi(&fmt);
1024                         if (spec->precision < 0)
1025                                 spec->precision = 0;
1026                 } else if (*fmt == '*') {
1027                         /* it's the next argument */
1028                         spec->type = FORMAT_TYPE_PRECISION;
1029                         return ++fmt - start;
1030                 }
1031         }
1032
1033 qualifier:
1034         /* get the conversion qualifier */
1035         spec->qualifier = -1;
1036         if (*fmt == 'h' || _tolower(*fmt) == 'l' ||
1037             _tolower(*fmt) == 'z' || *fmt == 't') {
1038                 spec->qualifier = *fmt++;
1039                 if (unlikely(spec->qualifier == *fmt)) {
1040                         if (spec->qualifier == 'l') {
1041                                 spec->qualifier = 'L';
1042                                 ++fmt;
1043                         } else if (spec->qualifier == 'h') {
1044                                 spec->qualifier = 'H';
1045                                 ++fmt;
1046                         }
1047                 }
1048         }
1049
1050         /* default base */
1051         spec->base = 10;
1052         switch (*fmt) {
1053         case 'c':
1054                 spec->type = FORMAT_TYPE_CHAR;
1055                 return ++fmt - start;
1056
1057         case 's':
1058                 spec->type = FORMAT_TYPE_STR;
1059                 return ++fmt - start;
1060
1061         case 'p':
1062                 spec->type = FORMAT_TYPE_PTR;
1063                 return fmt - start;
1064                 /* skip alnum */
1065
1066         case 'n':
1067                 spec->type = FORMAT_TYPE_NRCHARS;
1068                 return ++fmt - start;
1069
1070         case '%':
1071                 spec->type = FORMAT_TYPE_PERCENT_CHAR;
1072                 return ++fmt - start;
1073
1074         /* integer number formats - set up the flags and "break" */
1075         case 'o':
1076                 spec->base = 8;
1077                 break;
1078
1079         case 'x':
1080                 spec->flags |= SMALL;
1081
1082         case 'X':
1083                 spec->base = 16;
1084                 break;
1085
1086         case 'd':
1087         case 'i':
1088                 spec->flags |= SIGN;
1089         case 'u':
1090                 break;
1091
1092         default:
1093                 spec->type = FORMAT_TYPE_INVALID;
1094                 return fmt - start;
1095         }
1096
1097         if (spec->qualifier == 'L')
1098                 spec->type = FORMAT_TYPE_LONG_LONG;
1099         else if (spec->qualifier == 'l') {
1100                 if (spec->flags & SIGN)
1101                         spec->type = FORMAT_TYPE_LONG;
1102                 else
1103                         spec->type = FORMAT_TYPE_ULONG;
1104         } else if (_tolower(spec->qualifier) == 'z') {
1105                 spec->type = FORMAT_TYPE_SIZE_T;
1106         } else if (spec->qualifier == 't') {
1107                 spec->type = FORMAT_TYPE_PTRDIFF;
1108         } else if (spec->qualifier == 'H') {
1109                 if (spec->flags & SIGN)
1110                         spec->type = FORMAT_TYPE_BYTE;
1111                 else
1112                         spec->type = FORMAT_TYPE_UBYTE;
1113         } else if (spec->qualifier == 'h') {
1114                 if (spec->flags & SIGN)
1115                         spec->type = FORMAT_TYPE_SHORT;
1116                 else
1117                         spec->type = FORMAT_TYPE_USHORT;
1118         } else {
1119                 if (spec->flags & SIGN)
1120                         spec->type = FORMAT_TYPE_INT;
1121                 else
1122                         spec->type = FORMAT_TYPE_UINT;
1123         }
1124
1125         return ++fmt - start;
1126 }
1127
1128 /**
1129  * vsnprintf - Format a string and place it in a buffer
1130  * @buf: The buffer to place the result into
1131  * @size: The size of the buffer, including the trailing null space
1132  * @fmt: The format string to use
1133  * @args: Arguments for the format string
1134  *
1135  * This function follows C99 vsnprintf, but has some extensions:
1136  * %pS output the name of a text symbol with offset
1137  * %ps output the name of a text symbol without offset
1138  * %pF output the name of a function pointer with its offset
1139  * %pf output the name of a function pointer without its offset
1140  * %pB output the name of a backtrace symbol with its offset
1141  * %pR output the address range in a struct resource with decoded flags
1142  * %pr output the address range in a struct resource with raw flags
1143  * %pM output a 6-byte MAC address with colons
1144  * %pm output a 6-byte MAC address without colons
1145  * %pI4 print an IPv4 address without leading zeros
1146  * %pi4 print an IPv4 address with leading zeros
1147  * %pI6 print an IPv6 address with colons
1148  * %pi6 print an IPv6 address without colons
1149  * %pI6c print an IPv6 address as specified by RFC 5952
1150  * %pU[bBlL] print a UUID/GUID in big or little endian using lower or upper
1151  *   case.
1152  * %n is ignored
1153  *
1154  * The return value is the number of characters which would
1155  * be generated for the given input, excluding the trailing
1156  * '\0', as per ISO C99. If you want to have the exact
1157  * number of characters written into @buf as return value
1158  * (not including the trailing '\0'), use vscnprintf(). If the
1159  * return is greater than or equal to @size, the resulting
1160  * string is truncated.
1161  *
1162  * If you're not already dealing with a va_list consider using snprintf().
1163  */
1164 int vsnprintf(char *buf, size_t size, const char *fmt, va_list args)
1165 {
1166         unsigned long long num;
1167         char *str, *end;
1168         struct printf_spec spec = {0};
1169
1170         /* Reject out-of-range values early.  Large positive sizes are
1171            used for unknown buffer sizes. */
1172         if (WARN_ON_ONCE((int) size < 0))
1173                 return 0;
1174
1175         str = buf;
1176         end = buf + size;
1177
1178         /* Make sure end is always >= buf */
1179         if (end < buf) {
1180                 end = ((void *)-1);
1181                 size = end - buf;
1182         }
1183
1184         while (*fmt) {
1185                 const char *old_fmt = fmt;
1186                 int read = format_decode(fmt, &spec);
1187
1188                 fmt += read;
1189
1190                 switch (spec.type) {
1191                 case FORMAT_TYPE_NONE: {
1192                         int copy = read;
1193                         if (str < end) {
1194                                 if (copy > end - str)
1195                                         copy = end - str;
1196                                 memcpy(str, old_fmt, copy);
1197                         }
1198                         str += read;
1199                         break;
1200                 }
1201
1202                 case FORMAT_TYPE_WIDTH:
1203                         spec.field_width = va_arg(args, int);
1204                         break;
1205
1206                 case FORMAT_TYPE_PRECISION:
1207                         spec.precision = va_arg(args, int);
1208                         break;
1209
1210                 case FORMAT_TYPE_CHAR: {
1211                         char c;
1212
1213                         if (!(spec.flags & LEFT)) {
1214                                 while (--spec.field_width > 0) {
1215                                         if (str < end)
1216                                                 *str = ' ';
1217                                         ++str;
1218
1219                                 }
1220                         }
1221                         c = (unsigned char) va_arg(args, int);
1222                         if (str < end)
1223                                 *str = c;
1224                         ++str;
1225                         while (--spec.field_width > 0) {
1226                                 if (str < end)
1227                                         *str = ' ';
1228                                 ++str;
1229                         }
1230                         break;
1231                 }
1232
1233                 case FORMAT_TYPE_STR:
1234                         str = string(str, end, va_arg(args, char *), spec);
1235                         break;
1236
1237                 case FORMAT_TYPE_PTR:
1238                         str = pointer(fmt+1, str, end, va_arg(args, void *),
1239                                       spec);
1240                         while (isalnum(*fmt))
1241                                 fmt++;
1242                         break;
1243
1244                 case FORMAT_TYPE_PERCENT_CHAR:
1245                         if (str < end)
1246                                 *str = '%';
1247                         ++str;
1248                         break;
1249
1250                 case FORMAT_TYPE_INVALID:
1251                         if (str < end)
1252                                 *str = '%';
1253                         ++str;
1254                         break;
1255
1256                 case FORMAT_TYPE_NRCHARS: {
1257                         u8 qualifier = spec.qualifier;
1258
1259                         if (qualifier == 'l') {
1260                                 long *ip = va_arg(args, long *);
1261                                 *ip = (str - buf);
1262                         } else if (_tolower(qualifier) == 'z') {
1263                                 size_t *ip = va_arg(args, size_t *);
1264                                 *ip = (str - buf);
1265                         } else {
1266                                 int *ip = va_arg(args, int *);
1267                                 *ip = (str - buf);
1268                         }
1269                         break;
1270                 }
1271
1272                 default:
1273                         switch (spec.type) {
1274                         case FORMAT_TYPE_LONG_LONG:
1275                                 num = va_arg(args, long long);
1276                                 break;
1277                         case FORMAT_TYPE_ULONG:
1278                                 num = va_arg(args, unsigned long);
1279                                 break;
1280                         case FORMAT_TYPE_LONG:
1281                                 num = va_arg(args, long);
1282                                 break;
1283                         case FORMAT_TYPE_SIZE_T:
1284                                 num = va_arg(args, size_t);
1285                                 break;
1286                         case FORMAT_TYPE_PTRDIFF:
1287                                 num = va_arg(args, ptrdiff_t);
1288                                 break;
1289                         case FORMAT_TYPE_UBYTE:
1290                                 num = (unsigned char) va_arg(args, int);
1291                                 break;
1292                         case FORMAT_TYPE_BYTE:
1293                                 num = (signed char) va_arg(args, int);
1294                                 break;
1295                         case FORMAT_TYPE_USHORT:
1296                                 num = (unsigned short) va_arg(args, int);
1297                                 break;
1298                         case FORMAT_TYPE_SHORT:
1299                                 num = (short) va_arg(args, int);
1300                                 break;
1301                         case FORMAT_TYPE_INT:
1302                                 num = (int) va_arg(args, int);
1303                                 break;
1304                         default:
1305                                 num = va_arg(args, unsigned int);
1306                         }
1307
1308                         str = number(str, end, num, spec);
1309                 }
1310         }
1311
1312         if (size > 0) {
1313                 if (str < end)
1314                         *str = '\0';
1315                 else
1316                         end[-1] = '\0';
1317         }
1318
1319         /* the trailing null byte doesn't count towards the total */
1320         return str-buf;
1321
1322 }
1323 EXPORT_SYMBOL(vsnprintf);
1324
1325 /**
1326  * vscnprintf - Format a string and place it in a buffer
1327  * @buf: The buffer to place the result into
1328  * @size: The size of the buffer, including the trailing null space
1329  * @fmt: The format string to use
1330  * @args: Arguments for the format string
1331  *
1332  * The return value is the number of characters which have been written into
1333  * the @buf not including the trailing '\0'. If @size is == 0 the function
1334  * returns 0.
1335  *
1336  * If you're not already dealing with a va_list consider using scnprintf().
1337  *
1338  * See the vsnprintf() documentation for format string extensions over C99.
1339  */
1340 int vscnprintf(char *buf, size_t size, const char *fmt, va_list args)
1341 {
1342         int i;
1343
1344         i = vsnprintf(buf, size, fmt, args);
1345
1346         if (likely(i < size))
1347                 return i;
1348         if (size != 0)
1349                 return size - 1;
1350         return 0;
1351 }
1352 EXPORT_SYMBOL(vscnprintf);
1353
1354 /**
1355  * snprintf - Format a string and place it in a buffer
1356  * @buf: The buffer to place the result into
1357  * @size: The size of the buffer, including the trailing null space
1358  * @fmt: The format string to use
1359  * @...: Arguments for the format string
1360  *
1361  * The return value is the number of characters which would be
1362  * generated for the given input, excluding the trailing null,
1363  * as per ISO C99.  If the return is greater than or equal to
1364  * @size, the resulting string is truncated.
1365  *
1366  * See the vsnprintf() documentation for format string extensions over C99.
1367  */
1368 int snprintf(char *buf, size_t size, const char *fmt, ...)
1369 {
1370         va_list args;
1371         int i;
1372
1373         va_start(args, fmt);
1374         i = vsnprintf(buf, size, fmt, args);
1375         va_end(args);
1376
1377         return i;
1378 }
1379 EXPORT_SYMBOL(snprintf);
1380
1381 /**
1382  * scnprintf - Format a string and place it in a buffer
1383  * @buf: The buffer to place the result into
1384  * @size: The size of the buffer, including the trailing null space
1385  * @fmt: The format string to use
1386  * @...: Arguments for the format string
1387  *
1388  * The return value is the number of characters written into @buf not including
1389  * the trailing '\0'. If @size is == 0 the function returns 0.
1390  */
1391
1392 int scnprintf(char *buf, size_t size, const char *fmt, ...)
1393 {
1394         va_list args;
1395         int i;
1396
1397         va_start(args, fmt);
1398         i = vscnprintf(buf, size, fmt, args);
1399         va_end(args);
1400
1401         return i;
1402 }
1403 EXPORT_SYMBOL(scnprintf);
1404
1405 /**
1406  * vsprintf - Format a string and place it in a buffer
1407  * @buf: The buffer to place the result into
1408  * @fmt: The format string to use
1409  * @args: Arguments for the format string
1410  *
1411  * The function returns the number of characters written
1412  * into @buf. Use vsnprintf() or vscnprintf() in order to avoid
1413  * buffer overflows.
1414  *
1415  * If you're not already dealing with a va_list consider using sprintf().
1416  *
1417  * See the vsnprintf() documentation for format string extensions over C99.
1418  */
1419 int vsprintf(char *buf, const char *fmt, va_list args)
1420 {
1421         return vsnprintf(buf, INT_MAX, fmt, args);
1422 }
1423 EXPORT_SYMBOL(vsprintf);
1424
1425 /**
1426  * sprintf - Format a string and place it in a buffer
1427  * @buf: The buffer to place the result into
1428  * @fmt: The format string to use
1429  * @...: Arguments for the format string
1430  *
1431  * The function returns the number of characters written
1432  * into @buf. Use snprintf() or scnprintf() in order to avoid
1433  * buffer overflows.
1434  *
1435  * See the vsnprintf() documentation for format string extensions over C99.
1436  */
1437 int sprintf(char *buf, const char *fmt, ...)
1438 {
1439         va_list args;
1440         int i;
1441
1442         va_start(args, fmt);
1443         i = vsnprintf(buf, INT_MAX, fmt, args);
1444         va_end(args);
1445
1446         return i;
1447 }
1448 EXPORT_SYMBOL(sprintf);
1449
1450 #ifdef CONFIG_BINARY_PRINTF
1451 /*
1452  * bprintf service:
1453  * vbin_printf() - VA arguments to binary data
1454  * bstr_printf() - Binary data to text string
1455  */
1456
1457 /**
1458  * vbin_printf - Parse a format string and place args' binary value in a buffer
1459  * @bin_buf: The buffer to place args' binary value
1460  * @size: The size of the buffer(by words(32bits), not characters)
1461  * @fmt: The format string to use
1462  * @args: Arguments for the format string
1463  *
1464  * The format follows C99 vsnprintf, except %n is ignored, and its argument
1465  * is skiped.
1466  *
1467  * The return value is the number of words(32bits) which would be generated for
1468  * the given input.
1469  *
1470  * NOTE:
1471  * If the return value is greater than @size, the resulting bin_buf is NOT
1472  * valid for bstr_printf().
1473  */
1474 int vbin_printf(u32 *bin_buf, size_t size, const char *fmt, va_list args)
1475 {
1476         struct printf_spec spec = {0};
1477         char *str, *end;
1478
1479         str = (char *)bin_buf;
1480         end = (char *)(bin_buf + size);
1481
1482 #define save_arg(type)                                                  \
1483 do {                                                                    \
1484         if (sizeof(type) == 8) {                                        \
1485                 unsigned long long value;                               \
1486                 str = PTR_ALIGN(str, sizeof(u32));                      \
1487                 value = va_arg(args, unsigned long long);               \
1488                 if (str + sizeof(type) <= end) {                        \
1489                         *(u32 *)str = *(u32 *)&value;                   \
1490                         *(u32 *)(str + 4) = *((u32 *)&value + 1);       \
1491                 }                                                       \
1492         } else {                                                        \
1493                 unsigned long value;                                    \
1494                 str = PTR_ALIGN(str, sizeof(type));                     \
1495                 value = va_arg(args, int);                              \
1496                 if (str + sizeof(type) <= end)                          \
1497                         *(typeof(type) *)str = (type)value;             \
1498         }                                                               \
1499         str += sizeof(type);                                            \
1500 } while (0)
1501
1502         while (*fmt) {
1503                 int read = format_decode(fmt, &spec);
1504
1505                 fmt += read;
1506
1507                 switch (spec.type) {
1508                 case FORMAT_TYPE_NONE:
1509                 case FORMAT_TYPE_INVALID:
1510                 case FORMAT_TYPE_PERCENT_CHAR:
1511                         break;
1512
1513                 case FORMAT_TYPE_WIDTH:
1514                 case FORMAT_TYPE_PRECISION:
1515                         save_arg(int);
1516                         break;
1517
1518                 case FORMAT_TYPE_CHAR:
1519                         save_arg(char);
1520                         break;
1521
1522                 case FORMAT_TYPE_STR: {
1523                         const char *save_str = va_arg(args, char *);
1524                         size_t len;
1525
1526                         if ((unsigned long)save_str > (unsigned long)-PAGE_SIZE
1527                                         || (unsigned long)save_str < PAGE_SIZE)
1528                                 save_str = "(null)";
1529                         len = strlen(save_str) + 1;
1530                         if (str + len < end)
1531                                 memcpy(str, save_str, len);
1532                         str += len;
1533                         break;
1534                 }
1535
1536                 case FORMAT_TYPE_PTR:
1537                         save_arg(void *);
1538                         /* skip all alphanumeric pointer suffixes */
1539                         while (isalnum(*fmt))
1540                                 fmt++;
1541                         break;
1542
1543                 case FORMAT_TYPE_NRCHARS: {
1544                         /* skip %n 's argument */
1545                         u8 qualifier = spec.qualifier;
1546                         void *skip_arg;
1547                         if (qualifier == 'l')
1548                                 skip_arg = va_arg(args, long *);
1549                         else if (_tolower(qualifier) == 'z')
1550                                 skip_arg = va_arg(args, size_t *);
1551                         else
1552                                 skip_arg = va_arg(args, int *);
1553                         break;
1554                 }
1555
1556                 default:
1557                         switch (spec.type) {
1558
1559                         case FORMAT_TYPE_LONG_LONG:
1560                                 save_arg(long long);
1561                                 break;
1562                         case FORMAT_TYPE_ULONG:
1563                         case FORMAT_TYPE_LONG:
1564                                 save_arg(unsigned long);
1565                                 break;
1566                         case FORMAT_TYPE_SIZE_T:
1567                                 save_arg(size_t);
1568                                 break;
1569                         case FORMAT_TYPE_PTRDIFF:
1570                                 save_arg(ptrdiff_t);
1571                                 break;
1572                         case FORMAT_TYPE_UBYTE:
1573                         case FORMAT_TYPE_BYTE:
1574                                 save_arg(char);
1575                                 break;
1576                         case FORMAT_TYPE_USHORT:
1577                         case FORMAT_TYPE_SHORT:
1578                                 save_arg(short);
1579                                 break;
1580                         default:
1581                                 save_arg(int);
1582                         }
1583                 }
1584         }
1585
1586         return (u32 *)(PTR_ALIGN(str, sizeof(u32))) - bin_buf;
1587 #undef save_arg
1588 }
1589 EXPORT_SYMBOL_GPL(vbin_printf);
1590
1591 /**
1592  * bstr_printf - Format a string from binary arguments and place it in a buffer
1593  * @buf: The buffer to place the result into
1594  * @size: The size of the buffer, including the trailing null space
1595  * @fmt: The format string to use
1596  * @bin_buf: Binary arguments for the format string
1597  *
1598  * This function like C99 vsnprintf, but the difference is that vsnprintf gets
1599  * arguments from stack, and bstr_printf gets arguments from @bin_buf which is
1600  * a binary buffer that generated by vbin_printf.
1601  *
1602  * The format follows C99 vsnprintf, but has some extensions:
1603  *  see vsnprintf comment for details.
1604  *
1605  * The return value is the number of characters which would
1606  * be generated for the given input, excluding the trailing
1607  * '\0', as per ISO C99. If you want to have the exact
1608  * number of characters written into @buf as return value
1609  * (not including the trailing '\0'), use vscnprintf(). If the
1610  * return is greater than or equal to @size, the resulting
1611  * string is truncated.
1612  */
1613 int bstr_printf(char *buf, size_t size, const char *fmt, const u32 *bin_buf)
1614 {
1615         struct printf_spec spec = {0};
1616         char *str, *end;
1617         const char *args = (const char *)bin_buf;
1618
1619         if (WARN_ON_ONCE((int) size < 0))
1620                 return 0;
1621
1622         str = buf;
1623         end = buf + size;
1624
1625 #define get_arg(type)                                                   \
1626 ({                                                                      \
1627         typeof(type) value;                                             \
1628         if (sizeof(type) == 8) {                                        \
1629                 args = PTR_ALIGN(args, sizeof(u32));                    \
1630                 *(u32 *)&value = *(u32 *)args;                          \
1631                 *((u32 *)&value + 1) = *(u32 *)(args + 4);              \
1632         } else {                                                        \
1633                 args = PTR_ALIGN(args, sizeof(type));                   \
1634                 value = *(typeof(type) *)args;                          \
1635         }                                                               \
1636         args += sizeof(type);                                           \
1637         value;                                                          \
1638 })
1639
1640         /* Make sure end is always >= buf */
1641         if (end < buf) {
1642                 end = ((void *)-1);
1643                 size = end - buf;
1644         }
1645
1646         while (*fmt) {
1647                 const char *old_fmt = fmt;
1648                 int read = format_decode(fmt, &spec);
1649
1650                 fmt += read;
1651
1652                 switch (spec.type) {
1653                 case FORMAT_TYPE_NONE: {
1654                         int copy = read;
1655                         if (str < end) {
1656                                 if (copy > end - str)
1657                                         copy = end - str;
1658                                 memcpy(str, old_fmt, copy);
1659                         }
1660                         str += read;
1661                         break;
1662                 }
1663
1664                 case FORMAT_TYPE_WIDTH:
1665                         spec.field_width = get_arg(int);
1666                         break;
1667
1668                 case FORMAT_TYPE_PRECISION:
1669                         spec.precision = get_arg(int);
1670                         break;
1671
1672                 case FORMAT_TYPE_CHAR: {
1673                         char c;
1674
1675                         if (!(spec.flags & LEFT)) {
1676                                 while (--spec.field_width > 0) {
1677                                         if (str < end)
1678                                                 *str = ' ';
1679                                         ++str;
1680                                 }
1681                         }
1682                         c = (unsigned char) get_arg(char);
1683                         if (str < end)
1684                                 *str = c;
1685                         ++str;
1686                         while (--spec.field_width > 0) {
1687                                 if (str < end)
1688                                         *str = ' ';
1689                                 ++str;
1690                         }
1691                         break;
1692                 }
1693
1694                 case FORMAT_TYPE_STR: {
1695                         const char *str_arg = args;
1696                         args += strlen(str_arg) + 1;
1697                         str = string(str, end, (char *)str_arg, spec);
1698                         break;
1699                 }
1700
1701                 case FORMAT_TYPE_PTR:
1702                         str = pointer(fmt+1, str, end, get_arg(void *), spec);
1703                         while (isalnum(*fmt))
1704                                 fmt++;
1705                         break;
1706
1707                 case FORMAT_TYPE_PERCENT_CHAR:
1708                 case FORMAT_TYPE_INVALID:
1709                         if (str < end)
1710                                 *str = '%';
1711                         ++str;
1712                         break;
1713
1714                 case FORMAT_TYPE_NRCHARS:
1715                         /* skip */
1716                         break;
1717
1718                 default: {
1719                         unsigned long long num;
1720
1721                         switch (spec.type) {
1722
1723                         case FORMAT_TYPE_LONG_LONG:
1724                                 num = get_arg(long long);
1725                                 break;
1726                         case FORMAT_TYPE_ULONG:
1727                         case FORMAT_TYPE_LONG:
1728                                 num = get_arg(unsigned long);
1729                                 break;
1730                         case FORMAT_TYPE_SIZE_T:
1731                                 num = get_arg(size_t);
1732                                 break;
1733                         case FORMAT_TYPE_PTRDIFF:
1734                                 num = get_arg(ptrdiff_t);
1735                                 break;
1736                         case FORMAT_TYPE_UBYTE:
1737                                 num = get_arg(unsigned char);
1738                                 break;
1739                         case FORMAT_TYPE_BYTE:
1740                                 num = get_arg(signed char);
1741                                 break;
1742                         case FORMAT_TYPE_USHORT:
1743                                 num = get_arg(unsigned short);
1744                                 break;
1745                         case FORMAT_TYPE_SHORT:
1746                                 num = get_arg(short);
1747                                 break;
1748                         case FORMAT_TYPE_UINT:
1749                                 num = get_arg(unsigned int);
1750                                 break;
1751                         default:
1752                                 num = get_arg(int);
1753                         }
1754
1755                         str = number(str, end, num, spec);
1756                 } /* default: */
1757                 } /* switch(spec.type) */
1758         } /* while(*fmt) */
1759
1760         if (size > 0) {
1761                 if (str < end)
1762                         *str = '\0';
1763                 else
1764                         end[-1] = '\0';
1765         }
1766
1767 #undef get_arg
1768
1769         /* the trailing null byte doesn't count towards the total */
1770         return str - buf;
1771 }
1772 EXPORT_SYMBOL_GPL(bstr_printf);
1773
1774 /**
1775  * bprintf - Parse a format string and place args' binary value in a buffer
1776  * @bin_buf: The buffer to place args' binary value
1777  * @size: The size of the buffer(by words(32bits), not characters)
1778  * @fmt: The format string to use
1779  * @...: Arguments for the format string
1780  *
1781  * The function returns the number of words(u32) written
1782  * into @bin_buf.
1783  */
1784 int bprintf(u32 *bin_buf, size_t size, const char *fmt, ...)
1785 {
1786         va_list args;
1787         int ret;
1788
1789         va_start(args, fmt);
1790         ret = vbin_printf(bin_buf, size, fmt, args);
1791         va_end(args);
1792
1793         return ret;
1794 }
1795 EXPORT_SYMBOL_GPL(bprintf);
1796
1797 #endif /* CONFIG_BINARY_PRINTF */
1798
1799 /**
1800  * vsscanf - Unformat a buffer into a list of arguments
1801  * @buf:        input buffer
1802  * @fmt:        format of buffer
1803  * @args:       arguments
1804  */
1805 int vsscanf(const char *buf, const char *fmt, va_list args)
1806 {
1807         const char *str = buf;
1808         char *next;
1809         char digit;
1810         int num = 0;
1811         u8 qualifier;
1812         u8 base;
1813         s16 field_width;
1814         bool is_sign;
1815
1816         while (*fmt && *str) {
1817                 /* skip any white space in format */
1818                 /* white space in format matchs any amount of
1819                  * white space, including none, in the input.
1820                  */
1821                 if (isspace(*fmt)) {
1822                         fmt = skip_spaces(++fmt);
1823                         str = skip_spaces(str);
1824                 }
1825
1826                 /* anything that is not a conversion must match exactly */
1827                 if (*fmt != '%' && *fmt) {
1828                         if (*fmt++ != *str++)
1829                                 break;
1830                         continue;
1831                 }
1832
1833                 if (!*fmt)
1834                         break;
1835                 ++fmt;
1836
1837                 /* skip this conversion.
1838                  * advance both strings to next white space
1839                  */
1840                 if (*fmt == '*') {
1841                         while (!isspace(*fmt) && *fmt != '%' && *fmt)
1842                                 fmt++;
1843                         while (!isspace(*str) && *str)
1844                                 str++;
1845                         continue;
1846                 }
1847
1848                 /* get field width */
1849                 field_width = -1;
1850                 if (isdigit(*fmt))
1851                         field_width = skip_atoi(&fmt);
1852
1853                 /* get conversion qualifier */
1854                 qualifier = -1;
1855                 if (*fmt == 'h' || _tolower(*fmt) == 'l' ||
1856                     _tolower(*fmt) == 'z') {
1857                         qualifier = *fmt++;
1858                         if (unlikely(qualifier == *fmt)) {
1859                                 if (qualifier == 'h') {
1860                                         qualifier = 'H';
1861                                         fmt++;
1862                                 } else if (qualifier == 'l') {
1863                                         qualifier = 'L';
1864                                         fmt++;
1865                                 }
1866                         }
1867                 }
1868
1869                 if (!*fmt || !*str)
1870                         break;
1871
1872                 base = 10;
1873                 is_sign = 0;
1874
1875                 switch (*fmt++) {
1876                 case 'c':
1877                 {
1878                         char *s = (char *)va_arg(args, char*);
1879                         if (field_width == -1)
1880                                 field_width = 1;
1881                         do {
1882                                 *s++ = *str++;
1883                         } while (--field_width > 0 && *str);
1884                         num++;
1885                 }
1886                 continue;
1887                 case 's':
1888                 {
1889                         char *s = (char *)va_arg(args, char *);
1890                         if (field_width == -1)
1891                                 field_width = SHRT_MAX;
1892                         /* first, skip leading white space in buffer */
1893                         str = skip_spaces(str);
1894
1895                         /* now copy until next white space */
1896                         while (*str && !isspace(*str) && field_width--)
1897                                 *s++ = *str++;
1898                         *s = '\0';
1899                         num++;
1900                 }
1901                 continue;
1902                 case 'n':
1903                         /* return number of characters read so far */
1904                 {
1905                         int *i = (int *)va_arg(args, int*);
1906                         *i = str - buf;
1907                 }
1908                 continue;
1909                 case 'o':
1910                         base = 8;
1911                         break;
1912                 case 'x':
1913                 case 'X':
1914                         base = 16;
1915                         break;
1916                 case 'i':
1917                         base = 0;
1918                 case 'd':
1919                         is_sign = 1;
1920                 case 'u':
1921                         break;
1922                 case '%':
1923                         /* looking for '%' in str */
1924                         if (*str++ != '%')
1925                                 return num;
1926                         continue;
1927                 default:
1928                         /* invalid format; stop here */
1929                         return num;
1930                 }
1931
1932                 /* have some sort of integer conversion.
1933                  * first, skip white space in buffer.
1934                  */
1935                 str = skip_spaces(str);
1936
1937                 digit = *str;
1938                 if (is_sign && digit == '-')
1939                         digit = *(str + 1);
1940
1941                 if (!digit
1942                     || (base == 16 && !isxdigit(digit))
1943                     || (base == 10 && !isdigit(digit))
1944                     || (base == 8 && (!isdigit(digit) || digit > '7'))
1945                     || (base == 0 && !isdigit(digit)))
1946                         break;
1947
1948                 switch (qualifier) {
1949                 case 'H':       /* that's 'hh' in format */
1950                         if (is_sign) {
1951                                 signed char *s = (signed char *)va_arg(args, signed char *);
1952                                 *s = (signed char)simple_strtol(str, &next, base);
1953                         } else {
1954                                 unsigned char *s = (unsigned char *)va_arg(args, unsigned char *);
1955                                 *s = (unsigned char)simple_strtoul(str, &next, base);
1956                         }
1957                         break;
1958                 case 'h':
1959                         if (is_sign) {
1960                                 short *s = (short *)va_arg(args, short *);
1961                                 *s = (short)simple_strtol(str, &next, base);
1962                         } else {
1963                                 unsigned short *s = (unsigned short *)va_arg(args, unsigned short *);
1964                                 *s = (unsigned short)simple_strtoul(str, &next, base);
1965                         }
1966                         break;
1967                 case 'l':
1968                         if (is_sign) {
1969                                 long *l = (long *)va_arg(args, long *);
1970                                 *l = simple_strtol(str, &next, base);
1971                         } else {
1972                                 unsigned long *l = (unsigned long *)va_arg(args, unsigned long *);
1973                                 *l = simple_strtoul(str, &next, base);
1974                         }
1975                         break;
1976                 case 'L':
1977                         if (is_sign) {
1978                                 long long *l = (long long *)va_arg(args, long long *);
1979                                 *l = simple_strtoll(str, &next, base);
1980                         } else {
1981                                 unsigned long long *l = (unsigned long long *)va_arg(args, unsigned long long *);
1982                                 *l = simple_strtoull(str, &next, base);
1983                         }
1984                         break;
1985                 case 'Z':
1986                 case 'z':
1987                 {
1988                         size_t *s = (size_t *)va_arg(args, size_t *);
1989                         *s = (size_t)simple_strtoul(str, &next, base);
1990                 }
1991                 break;
1992                 default:
1993                         if (is_sign) {
1994                                 int *i = (int *)va_arg(args, int *);
1995                                 *i = (int)simple_strtol(str, &next, base);
1996                         } else {
1997                                 unsigned int *i = (unsigned int *)va_arg(args, unsigned int*);
1998                                 *i = (unsigned int)simple_strtoul(str, &next, base);
1999                         }
2000                         break;
2001                 }
2002                 num++;
2003
2004                 if (!next)
2005                         break;
2006                 str = next;
2007         }
2008
2009         /*
2010          * Now we've come all the way through so either the input string or the
2011          * format ended. In the former case, there can be a %n at the current
2012          * position in the format that needs to be filled.
2013          */
2014         if (*fmt == '%' && *(fmt + 1) == 'n') {
2015                 int *p = (int *)va_arg(args, int *);
2016                 *p = str - buf;
2017         }
2018
2019         return num;
2020 }
2021 EXPORT_SYMBOL(vsscanf);
2022
2023 /**
2024  * sscanf - Unformat a buffer into a list of arguments
2025  * @buf:        input buffer
2026  * @fmt:        formatting of buffer
2027  * @...:        resulting arguments
2028  */
2029 int sscanf(const char *buf, const char *fmt, ...)
2030 {
2031         va_list args;
2032         int i;
2033
2034         va_start(args, fmt);
2035         i = vsscanf(buf, fmt, args);
2036         va_end(args);
2037
2038         return i;
2039 }
2040 EXPORT_SYMBOL(sscanf);