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>       /* for KSYM_SYMBOL_LEN */
  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/math64.h>
  27 #include <linux/uaccess.h>
  28 #include <linux/ioport.h>
  29 #include <linux/dcache.h>
  30 #include <linux/cred.h>
  31 #include <net/addrconf.h>
  32
  33 #include <asm/page.h>           /* for PAGE_SIZE */
  34 #include <asm/sections.h>       /* for dereference_function_descriptor() */
  35
  36 #include "kstrtox.h"
  37
  38 /**
  39  * simple_strtoull - convert a string to an unsigned long long
  40  * @cp: The start of the string
  41  * @endp: A pointer to the end of the parsed string will be placed here
  42  * @base: The number base to use
  43  *
  44  * This function is obsolete. Please use kstrtoull instead.
  45  */
  46 unsigned long long simple_strtoull(const char *cp, char **endp, unsigned int base)
  47 {
  48         unsigned long long result;
  49         unsigned int rv;
  50
  51         cp = _parse_integer_fixup_radix(cp, &base);
  52         rv = _parse_integer(cp, base, &result);
  53         /* FIXME */
  54         cp += (rv & ~KSTRTOX_OVERFLOW);
  55
  56         if (endp)
  57                 *endp = (char *)cp;
  58
  59         return result;
  60 }
  61 EXPORT_SYMBOL(simple_strtoull);
  62
  63 /**
  64  * simple_strtoul - convert a string to an unsigned long
  65  * @cp: The start of the string
  66  * @endp: A pointer to the end of the parsed string will be placed here
  67  * @base: The number base to use
  68  *
  69  * This function is obsolete. Please use kstrtoul instead.
  70  */
  71 unsigned long simple_strtoul(const char *cp, char **endp, unsigned int base)
  72 {
  73         return simple_strtoull(cp, endp, base);
  74 }
  75 EXPORT_SYMBOL(simple_strtoul);
  76
  77 /**
  78  * simple_strtol - convert a string to a signed long
  79  * @cp: The start of the string
  80  * @endp: A pointer to the end of the parsed string will be placed here
  81  * @base: The number base to use
  82  *
  83  * This function is obsolete. Please use kstrtol instead.
  84  */
  85 long simple_strtol(const char *cp, char **endp, unsigned int base)
  86 {
  87         if (*cp == '-')
  88                 return -simple_strtoul(cp + 1, endp, base);
  89
  90         return simple_strtoul(cp, endp, base);
  91 }
  92 EXPORT_SYMBOL(simple_strtol);
  93
  94 /**
  95  * simple_strtoll - convert a string to a signed long long
  96  * @cp: The start of the string
  97  * @endp: A pointer to the end of the parsed string will be placed here
  98  * @base: The number base to use
  99  *
 100  * This function is obsolete. Please use kstrtoll instead.
 101  */
 102 long long simple_strtoll(const char *cp, char **endp, unsigned int base)
 103 {
 104         if (*cp == '-')
 105                 return -simple_strtoull(cp + 1, endp, base);
 106
 107         return simple_strtoull(cp, endp, base);
 108 }
 109 EXPORT_SYMBOL(simple_strtoll);
 110
 111 static noinline_for_stack
 112 int skip_atoi(const char **s)
 113 {
 114         int i = 0;
 115
 116         while (isdigit(**s))
 117                 i = i*10 + *((*s)++) - '0';
 118
 119         return i;
 120 }
 121
 122 /* Decimal conversion is by far the most typical, and is used
 123  * for /proc and /sys data. This directly impacts e.g. top performance
 124  * with many processes running. We optimize it for speed
 125  * using ideas described at <http://www.cs.uiowa.edu/~jones/bcd/divide.html>
 126  * (with permission from the author, Douglas W. Jones).
 127  */
 128
 129 #if BITS_PER_LONG != 32 || BITS_PER_LONG_LONG != 64
 130 /* Formats correctly any integer in [0, 999999999] */
 131 static noinline_for_stack
 132 char *put_dec_full9(char *buf, unsigned q)
 133 {
 134         unsigned r;
 135
 136         /*
 137          * Possible ways to approx. divide by 10
 138          * (x * 0x1999999a) >> 32 x < 1073741829 (multiply must be 64-bit)
 139          * (x * 0xcccd) >> 19     x <      81920 (x < 262149 when 64-bit mul)
 140          * (x * 0x6667) >> 18     x <      43699
 141          * (x * 0x3334) >> 17     x <      16389
 142          * (x * 0x199a) >> 16     x <      16389
 143          * (x * 0x0ccd) >> 15     x <      16389
 144          * (x * 0x0667) >> 14     x <       2739
 145          * (x * 0x0334) >> 13     x <       1029
 146          * (x * 0x019a) >> 12     x <       1029
 147          * (x * 0x00cd) >> 11     x <       1029 shorter code than * 0x67 (on i386)
 148          * (x * 0x0067) >> 10     x <        179
 149          * (x * 0x0034) >>  9     x <         69 same
 150          * (x * 0x001a) >>  8     x <         69 same
 151          * (x * 0x000d) >>  7     x <         69 same, shortest code (on i386)
 152          * (x * 0x0007) >>  6     x <         19
 153          * See <http://www.cs.uiowa.edu/~jones/bcd/divide.html>
 154          */
 155         r      = (q * (uint64_t)0x1999999a) >> 32;
 156         *buf++ = (q - 10 * r) + '0'; /* 1 */
 157         q      = (r * (uint64_t)0x1999999a) >> 32;
 158         *buf++ = (r - 10 * q) + '0'; /* 2 */
 159         r      = (q * (uint64_t)0x1999999a) >> 32;
 160         *buf++ = (q - 10 * r) + '0'; /* 3 */
 161         q      = (r * (uint64_t)0x1999999a) >> 32;
 162         *buf++ = (r - 10 * q) + '0'; /* 4 */
 163         r      = (q * (uint64_t)0x1999999a) >> 32;
 164         *buf++ = (q - 10 * r) + '0'; /* 5 */
 165         /* Now value is under 10000, can avoid 64-bit multiply */
 166         q      = (r * 0x199a) >> 16;
 167         *buf++ = (r - 10 * q)  + '0'; /* 6 */
 168         r      = (q * 0xcd) >> 11;
 169         *buf++ = (q - 10 * r)  + '0'; /* 7 */
 170         q      = (r * 0xcd) >> 11;
 171         *buf++ = (r - 10 * q) + '0'; /* 8 */
 172         *buf++ = q + '0'; /* 9 */
 173         return buf;
 174 }
 175 #endif
 176
 177 /* Similar to above but do not pad with zeros.
 178  * Code can be easily arranged to print 9 digits too, but our callers
 179  * always call put_dec_full9() instead when the number has 9 decimal digits.
 180  */
 181 static noinline_for_stack
 182 char *put_dec_trunc8(char *buf, unsigned r)
 183 {
 184         unsigned q;
 185
 186         /* Copy of previous function's body with added early returns */
 187         while (r >= 10000) {
 188                 q = r + '0';
 189                 r  = (r * (uint64_t)0x1999999a) >> 32;
 190                 *buf++ = q - 10*r;
 191         }
 192
 193         q      = (r * 0x199a) >> 16;    /* r <= 9999 */
 194         *buf++ = (r - 10 * q)  + '0';
 195         if (q == 0)
 196                 return buf;
 197         r      = (q * 0xcd) >> 11;      /* q <= 999 */
 198         *buf++ = (q - 10 * r)  + '0';
 199         if (r == 0)
 200                 return buf;
 201         q      = (r * 0xcd) >> 11;      /* r <= 99 */
 202         *buf++ = (r - 10 * q) + '0';
 203         if (q == 0)
 204                 return buf;
 205         *buf++ = q + '0';                /* q <= 9 */
 206         return buf;
 207 }
 208
 209 /* There are two algorithms to print larger numbers.
 210  * One is generic: divide by 1000000000 and repeatedly print
 211  * groups of (up to) 9 digits. It's conceptually simple,
 212  * but requires a (unsigned long long) / 1000000000 division.
 213  *
 214  * Second algorithm splits 64-bit unsigned long long into 16-bit chunks,
 215  * manipulates them cleverly and generates groups of 4 decimal digits.
 216  * It so happens that it does NOT require long long division.
 217  *
 218  * If long is > 32 bits, division of 64-bit values is relatively easy,
 219  * and we will use the first algorithm.
 220  * If long long is > 64 bits (strange architecture with VERY large long long),
 221  * second algorithm can't be used, and we again use the first one.
 222  *
 223  * Else (if long is 32 bits and long long is 64 bits) we use second one.
 224  */
 225
 226 #if BITS_PER_LONG != 32 || BITS_PER_LONG_LONG != 64
 227
 228 /* First algorithm: generic */
 229
 230 static
 231 char *put_dec(char *buf, unsigned long long n)
 232 {
 233         if (n >= 100*1000*1000) {
 234                 while (n >= 1000*1000*1000)
 235                         buf = put_dec_full9(buf, do_div(n, 1000*1000*1000));
 236                 if (n >= 100*1000*1000)
 237                         return put_dec_full9(buf, n);
 238         }
 239         return put_dec_trunc8(buf, n);
 240 }
 241
 242 #else
 243
 244 /* Second algorithm: valid only for 64-bit long longs */
 245
 246 /* See comment in put_dec_full9 for choice of constants */
 247 static noinline_for_stack
 248 void put_dec_full4(char *buf, unsigned q)
 249 {
 250         unsigned r;
 251         r      = (q * 0xccd) >> 15;
 252         buf[0] = (q - 10 * r) + '0';
 253         q      = (r * 0xcd) >> 11;
 254         buf[1] = (r - 10 * q)  + '0';
 255         r      = (q * 0xcd) >> 11;
 256         buf[2] = (q - 10 * r)  + '0';
 257         buf[3] = r + '0';
 258 }
 259
 260 /*
 261  * Call put_dec_full4 on x % 10000, return x / 10000.
 262  * The approximation x/10000 == (x * 0x346DC5D7) >> 43
 263  * holds for all x < 1,128,869,999.  The largest value this
 264  * helper will ever be asked to convert is 1,125,520,955.
 265  * (d1 in the put_dec code, assuming n is all-ones).
 266  */
 267 static
 268 unsigned put_dec_helper4(char *buf, unsigned x)
 269 {
 270         uint32_t q = (x * (uint64_t)0x346DC5D7) >> 43;
 271
 272         put_dec_full4(buf, x - q * 10000);
 273         return q;
 274 }
 275
 276 /* Based on code by Douglas W. Jones found at
 277  * <http://www.cs.uiowa.edu/~jones/bcd/decimal.html#sixtyfour>
 278  * (with permission from the author).
 279  * Performs no 64-bit division and hence should be fast on 32-bit machines.
 280  */
 281 static
 282 char *put_dec(char *buf, unsigned long long n)
 283 {
 284         uint32_t d3, d2, d1, q, h;
 285
 286         if (n < 100*1000*1000)
 287                 return put_dec_trunc8(buf, n);
 288
 289         d1  = ((uint32_t)n >> 16); /* implicit "& 0xffff" */
 290         h   = (n >> 32);
 291         d2  = (h      ) & 0xffff;
 292         d3  = (h >> 16); /* implicit "& 0xffff" */
 293
 294         q   = 656 * d3 + 7296 * d2 + 5536 * d1 + ((uint32_t)n & 0xffff);
 295         q = put_dec_helper4(buf, q);
 296
 297         q += 7671 * d3 + 9496 * d2 + 6 * d1;
 298         q = put_dec_helper4(buf+4, q);
 299
 300         q += 4749 * d3 + 42 * d2;
 301         q = put_dec_helper4(buf+8, q);
 302
 303         q += 281 * d3;
 304         buf += 12;
 305         if (q)
 306                 buf = put_dec_trunc8(buf, q);
 307         else while (buf[-1] == '0')
 308                 --buf;
 309
 310         return buf;
 311 }
 312
 313 #endif
 314
 315 /*
 316  * Convert passed number to decimal string.
 317  * Returns the length of string.  On buffer overflow, returns 0.
 318  *
 319  * If speed is not important, use snprintf(). It's easy to read the code.
 320  */
 321 int num_to_str(char *buf, int size, unsigned long long num)
 322 {
 323         char tmp[sizeof(num) * 3];
 324         int idx, len;
 325
 326         /* put_dec() may work incorrectly for num = 0 (generate "", not "0") */
 327         if (num <= 9) {
 328                 tmp[0] = '0' + num;
 329                 len = 1;
 330         } else {
 331                 len = put_dec(tmp, num) - tmp;
 332         }
 333
 334         if (len > size)
 335                 return 0;
 336         for (idx = 0; idx < len; ++idx)
 337                 buf[idx] = tmp[len - idx - 1];
 338         return len;
 339 }
 340
 341 #define ZEROPAD 1               /* pad with zero */
 342 #define SIGN    2               /* unsigned/signed long */
 343 #define PLUS    4               /* show plus */
 344 #define SPACE   8               /* space if plus */
 345 #define LEFT    16              /* left justified */
 346 #define SMALL   32              /* use lowercase in hex (must be 32 == 0x20) */
 347 #define SPECIAL 64              /* prefix hex with "0x", octal with "0" */
 348
 349 enum format_type {
 350         FORMAT_TYPE_NONE, /* Just a string part */
 351         FORMAT_TYPE_WIDTH,
 352         FORMAT_TYPE_PRECISION,
 353         FORMAT_TYPE_CHAR,
 354         FORMAT_TYPE_STR,
 355         FORMAT_TYPE_PTR,
 356         FORMAT_TYPE_PERCENT_CHAR,
 357         FORMAT_TYPE_INVALID,
 358         FORMAT_TYPE_LONG_LONG,
 359         FORMAT_TYPE_ULONG,
 360         FORMAT_TYPE_LONG,
 361         FORMAT_TYPE_UBYTE,
 362         FORMAT_TYPE_BYTE,
 363         FORMAT_TYPE_USHORT,
 364         FORMAT_TYPE_SHORT,
 365         FORMAT_TYPE_UINT,
 366         FORMAT_TYPE_INT,
 367         FORMAT_TYPE_NRCHARS,
 368         FORMAT_TYPE_SIZE_T,
 369         FORMAT_TYPE_PTRDIFF
 370 };
 371
 372 struct printf_spec {
 373         u8      type;           /* format_type enum */
 374         u8      flags;          /* flags to number() */
 375         u8      base;           /* number base, 8, 10 or 16 only */
 376         u8      qualifier;      /* number qualifier, one of 'hHlLtzZ' */
 377         s16     field_width;    /* width of output field */
 378         s16     precision;      /* # of digits/chars */
 379 };
 380
 381 static noinline_for_stack
 382 char *number(char *buf, char *end, unsigned long long num,
 383              struct printf_spec spec)
 384 {
 385         /* we are called with base 8, 10 or 16, only, thus don't need "G..."  */
 386         static const char digits[16] = "0123456789ABCDEF"; /* "GHIJKLMNOPQRSTUVWXYZ"; */
 387
 388         char tmp[66];
 389         char sign;
 390         char locase;
 391         int need_pfx = ((spec.flags & SPECIAL) && spec.base != 10);
 392         int i;
 393         bool is_zero = num == 0LL;
 394
 395         /* locase = 0 or 0x20. ORing digits or letters with 'locase'
 396          * produces same digits or (maybe lowercased) letters */
 397         locase = (spec.flags & SMALL);
 398         if (spec.flags & LEFT)
 399                 spec.flags &= ~ZEROPAD;
 400         sign = 0;
 401         if (spec.flags & SIGN) {
 402                 if ((signed long long)num < 0) {
 403                         sign = '-';
 404                         num = -(signed long long)num;
 405                         spec.field_width--;
 406                 } else if (spec.flags & PLUS) {
 407                         sign = '+';
 408                         spec.field_width--;
 409                 } else if (spec.flags & SPACE) {
 410                         sign = ' ';
 411                         spec.field_width--;
 412                 }
 413         }
 414         if (need_pfx) {
 415                 if (spec.base == 16)
 416                         spec.field_width -= 2;
 417                 else if (!is_zero)
 418                         spec.field_width--;
 419         }
 420
 421         /* generate full string in tmp[], in reverse order */
 422         i = 0;
 423         if (num < spec.base)
 424                 tmp[i++] = digits[num] | locase;
 425         /* Generic code, for any base:
 426         else do {
 427                 tmp[i++] = (digits[do_div(num,base)] | locase);
 428         } while (num != 0);
 429         */
 430         else if (spec.base != 10) { /* 8 or 16 */
 431                 int mask = spec.base - 1;
 432                 int shift = 3;
 433
 434                 if (spec.base == 16)
 435                         shift = 4;
 436                 do {
 437                         tmp[i++] = (digits[((unsigned char)num) & mask] | locase);
 438                         num >>= shift;
 439                 } while (num);
 440         } else { /* base 10 */
 441                 i = put_dec(tmp, num) - tmp;
 442         }
 443
 444         /* printing 100 using %2d gives "100", not "00" */
 445         if (i > spec.precision)
 446                 spec.precision = i;
 447         /* leading space padding */
 448         spec.field_width -= spec.precision;
 449         if (!(spec.flags & (ZEROPAD+LEFT))) {
 450                 while (--spec.field_width >= 0) {
 451                         if (buf < end)
 452                                 *buf = ' ';
 453                         ++buf;
 454                 }
 455         }
 456         /* sign */
 457         if (sign) {
 458                 if (buf < end)
 459                         *buf = sign;
 460                 ++buf;
 461         }
 462         /* "0x" / "0" prefix */
 463         if (need_pfx) {
 464                 if (spec.base == 16 || !is_zero) {
 465                         if (buf < end)
 466                                 *buf = '0';
 467                         ++buf;
 468                 }
 469                 if (spec.base == 16) {
 470                         if (buf < end)
 471                                 *buf = ('X' | locase);
 472                         ++buf;
 473                 }
 474         }
 475         /* zero or space padding */
 476         if (!(spec.flags & LEFT)) {
 477                 char c = (spec.flags & ZEROPAD) ? '0' : ' ';
 478                 while (--spec.field_width >= 0) {
 479                         if (buf < end)
 480                                 *buf = c;
 481                         ++buf;
 482                 }
 483         }
 484         /* hmm even more zero padding? */
 485         while (i <= --spec.precision) {
 486                 if (buf < end)
 487                         *buf = '0';
 488                 ++buf;
 489         }
 490         /* actual digits of result */
 491         while (--i >= 0) {
 492                 if (buf < end)
 493                         *buf = tmp[i];
 494                 ++buf;
 495         }
 496         /* trailing space padding */
 497         while (--spec.field_width >= 0) {
 498                 if (buf < end)
 499                         *buf = ' ';
 500                 ++buf;
 501         }
 502
 503         return buf;
 504 }
 505
 506 static noinline_for_stack
 507 char *string(char *buf, char *end, const char *s, struct printf_spec spec)
 508 {
 509         int len, i;
 510
 511         if ((unsigned long)s < PAGE_SIZE)
 512                 s = "(null)";
 513
 514         len = strnlen(s, spec.precision);
 515
 516         if (!(spec.flags & LEFT)) {
 517                 while (len < spec.field_width--) {
 518                         if (buf < end)
 519                                 *buf = ' ';
 520                         ++buf;
 521                 }
 522         }
 523         for (i = 0; i < len; ++i) {
 524                 if (buf < end)
 525                         *buf = *s;
 526                 ++buf; ++s;
 527         }
 528         while (len < spec.field_width--) {
 529                 if (buf < end)
 530                         *buf = ' ';
 531                 ++buf;
 532         }
 533
 534         return buf;
 535 }
 536
 537 static void widen(char *buf, char *end, unsigned len, unsigned spaces)
 538 {
 539         size_t size;
 540         if (buf >= end) /* nowhere to put anything */
 541                 return;
 542         size = end - buf;
 543         if (size <= spaces) {
 544                 memset(buf, ' ', size);
 545                 return;
 546         }
 547         if (len) {
 548                 if (len > size - spaces)
 549                         len = size - spaces;
 550                 memmove(buf + spaces, buf, len);
 551         }
 552         memset(buf, ' ', spaces);
 553 }
 554
 555 static noinline_for_stack
 556 char *dentry_name(char *buf, char *end, const struct dentry *d, struct printf_spec spec,
 557                   const char *fmt)
 558 {
 559         const char *array[4], *s;
 560         const struct dentry *p;
 561         int depth;
 562         int i, n;
 563
 564         switch (fmt[1]) {
 565                 case '2': case '3': case '4':
 566                         depth = fmt[1] - '0';
 567                         break;
 568                 default:
 569                         depth = 1;
 570         }
 571
 572         rcu_read_lock();
 573         for (i = 0; i < depth; i++, d = p) {
 574                 p = ACCESS_ONCE(d->d_parent);
 575                 array[i] = ACCESS_ONCE(d->d_name.name);
 576                 if (p == d) {
 577                         if (i)
 578                                 array[i] = "";
 579                         i++;
 580                         break;
 581                 }
 582         }
 583         s = array[--i];
 584         for (n = 0; n != spec.precision; n++, buf++) {
 585                 char c = *s++;
 586                 if (!c) {
 587                         if (!i)
 588                                 break;
 589                         c = '/';
 590                         s = array[--i];
 591                 }
 592                 if (buf < end)
 593                         *buf = c;
 594         }
 595         rcu_read_unlock();
 596         if (n < spec.field_width) {
 597                 /* we want to pad the sucker */
 598                 unsigned spaces = spec.field_width - n;
 599                 if (!(spec.flags & LEFT)) {
 600                         widen(buf - n, end, n, spaces);
 601                         return buf + spaces;
 602                 }
 603                 while (spaces--) {
 604                         if (buf < end)
 605                                 *buf = ' ';
 606                         ++buf;
 607                 }
 608         }
 609         return buf;
 610 }
 611
 612 static noinline_for_stack
 613 char *symbol_string(char *buf, char *end, void *ptr,
 614                     struct printf_spec spec, const char *fmt)
 615 {
 616         unsigned long value;
 617 #ifdef CONFIG_KALLSYMS
 618         char sym[KSYM_SYMBOL_LEN];
 619 #endif
 620
 621         if (fmt[1] == 'R')
 622                 ptr = __builtin_extract_return_addr(ptr);
 623         value = (unsigned long)ptr;
 624
 625 #ifdef CONFIG_KALLSYMS
 626         if (*fmt == 'B')
 627                 sprint_backtrace(sym, value);
 628         else if (*fmt != 'f' && *fmt != 's')
 629                 sprint_symbol(sym, value);
 630         else
 631                 sprint_symbol_no_offset(sym, value);
 632
 633         return string(buf, end, sym, spec);
 634 #else
 635         spec.field_width = 2 * sizeof(void *);
 636         spec.flags |= SPECIAL | SMALL | ZEROPAD;
 637         spec.base = 16;
 638
 639         return number(buf, end, value, spec);
 640 #endif
 641 }
 642
 643 static noinline_for_stack
 644 char *resource_string(char *buf, char *end, struct resource *res,
 645                       struct printf_spec spec, const char *fmt)
 646 {
 647 #ifndef IO_RSRC_PRINTK_SIZE
 648 #define IO_RSRC_PRINTK_SIZE     6
 649 #endif
 650
 651 #ifndef MEM_RSRC_PRINTK_SIZE
 652 #define MEM_RSRC_PRINTK_SIZE    10
 653 #endif
 654         static const struct printf_spec io_spec = {
 655                 .base = 16,
 656                 .field_width = IO_RSRC_PRINTK_SIZE,
 657                 .precision = -1,
 658                 .flags = SPECIAL | SMALL | ZEROPAD,
 659         };
 660         static const struct printf_spec mem_spec = {
 661                 .base = 16,
 662                 .field_width = MEM_RSRC_PRINTK_SIZE,
 663                 .precision = -1,
 664                 .flags = SPECIAL | SMALL | ZEROPAD,
 665         };
 666         static const struct printf_spec bus_spec = {
 667                 .base = 16,
 668                 .field_width = 2,
 669                 .precision = -1,
 670                 .flags = SMALL | ZEROPAD,
 671         };
 672         static const struct printf_spec dec_spec = {
 673                 .base = 10,
 674                 .precision = -1,
 675                 .flags = 0,
 676         };
 677         static const struct printf_spec str_spec = {
 678                 .field_width = -1,
 679                 .precision = 10,
 680                 .flags = LEFT,
 681         };
 682         static const struct printf_spec flag_spec = {
 683                 .base = 16,
 684                 .precision = -1,
 685                 .flags = SPECIAL | SMALL,
 686         };
 687
 688         /* 32-bit res (sizeof==4): 10 chars in dec, 10 in hex ("0x" + 8)
 689          * 64-bit res (sizeof==8): 20 chars in dec, 18 in hex ("0x" + 16) */
 690 #define RSRC_BUF_SIZE           ((2 * sizeof(resource_size_t)) + 4)
 691 #define FLAG_BUF_SIZE           (2 * sizeof(res->flags))
 692 #define DECODED_BUF_SIZE        sizeof("[mem - 64bit pref window disabled]")
 693 #define RAW_BUF_SIZE            sizeof("[mem - flags 0x]")
 694         char sym[max(2*RSRC_BUF_SIZE + DECODED_BUF_SIZE,
 695                      2*RSRC_BUF_SIZE + FLAG_BUF_SIZE + RAW_BUF_SIZE)];
 696
 697         char *p = sym, *pend = sym + sizeof(sym);
 698         int decode = (fmt[0] == 'R') ? 1 : 0;
 699         const struct printf_spec *specp;
 700
 701         *p++ = '[';
 702         if (res->flags & IORESOURCE_IO) {
 703                 p = string(p, pend, "io  ", str_spec);
 704                 specp = &io_spec;
 705         } else if (res->flags & IORESOURCE_MEM) {
 706                 p = string(p, pend, "mem ", str_spec);
 707                 specp = &mem_spec;
 708         } else if (res->flags & IORESOURCE_IRQ) {
 709                 p = string(p, pend, "irq ", str_spec);
 710                 specp = &dec_spec;
 711         } else if (res->flags & IORESOURCE_DMA) {
 712                 p = string(p, pend, "dma ", str_spec);
 713                 specp = &dec_spec;
 714         } else if (res->flags & IORESOURCE_BUS) {
 715                 p = string(p, pend, "bus ", str_spec);
 716                 specp = &bus_spec;
 717         } else {
 718                 p = string(p, pend, "??? ", str_spec);
 719                 specp = &mem_spec;
 720                 decode = 0;
 721         }
 722         p = number(p, pend, res->start, *specp);
 723         if (res->start != res->end) {
 724                 *p++ = '-';
 725                 p = number(p, pend, res->end, *specp);
 726         }
 727         if (decode) {
 728                 if (res->flags & IORESOURCE_MEM_64)
 729                         p = string(p, pend, " 64bit", str_spec);
 730                 if (res->flags & IORESOURCE_PREFETCH)
 731                         p = string(p, pend, " pref", str_spec);
 732                 if (res->flags & IORESOURCE_WINDOW)
 733                         p = string(p, pend, " window", str_spec);
 734                 if (res->flags & IORESOURCE_DISABLED)
 735                         p = string(p, pend, " disabled", str_spec);
 736         } else {
 737                 p = string(p, pend, " flags ", str_spec);
 738                 p = number(p, pend, res->flags, flag_spec);
 739         }
 740         *p++ = ']';
 741         *p = '\0';
 742
 743         return string(buf, end, sym, spec);
 744 }
 745
 746 static noinline_for_stack
 747 char *hex_string(char *buf, char *end, u8 *addr, struct printf_spec spec,
 748                  const char *fmt)
 749 {
 750         int i, len = 1;         /* if we pass '%ph[CDN]', field width remains
 751                                    negative value, fallback to the default */
 752         char separator;
 753
 754         if (spec.field_width == 0)
 755                 /* nothing to print */
 756                 return buf;
 757
 758         if (ZERO_OR_NULL_PTR(addr))
 759                 /* NULL pointer */
 760                 return string(buf, end, NULL, spec);
 761
 762         switch (fmt[1]) {
 763         case 'C':
 764                 separator = ':';
 765                 break;
 766         case 'D':
 767                 separator = '-';
 768                 break;
 769         case 'N':
 770                 separator = 0;
 771                 break;
 772         default:
 773                 separator = ' ';
 774                 break;
 775         }
 776
 777         if (spec.field_width > 0)
 778                 len = min_t(int, spec.field_width, 64);
 779
 780         for (i = 0; i < len && buf < end - 1; i++) {
 781                 buf = hex_byte_pack(buf, addr[i]);
 782
 783                 if (buf < end && separator && i != len - 1)
 784                         *buf++ = separator;
 785         }
 786
 787         return buf;
 788 }
 789
 790 static noinline_for_stack
 791 char *mac_address_string(char *buf, char *end, u8 *addr,
 792                          struct printf_spec spec, const char *fmt)
 793 {
 794         char mac_addr[sizeof("xx:xx:xx:xx:xx:xx")];
 795         char *p = mac_addr;
 796         int i;
 797         char separator;
 798         bool reversed = false;
 799
 800         switch (fmt[1]) {
 801         case 'F':
 802                 separator = '-';
 803                 break;
 804
 805         case 'R':
 806                 reversed = true;
 807                 /* fall through */
 808
 809         default:
 810                 separator = ':';
 811                 break;
 812         }
 813
 814         for (i = 0; i < 6; i++) {
 815                 if (reversed)
 816                         p = hex_byte_pack(p, addr[5 - i]);
 817                 else
 818                         p = hex_byte_pack(p, addr[i]);
 819
 820                 if (fmt[0] == 'M' && i != 5)
 821                         *p++ = separator;
 822         }
 823         *p = '\0';
 824
 825         return string(buf, end, mac_addr, spec);
 826 }
 827
 828 static noinline_for_stack
 829 char *ip4_string(char *p, const u8 *addr, const char *fmt)
 830 {
 831         int i;
 832         bool leading_zeros = (fmt[0] == 'i');
 833         int index;
 834         int step;
 835
 836         switch (fmt[2]) {
 837         case 'h':
 838 #ifdef __BIG_ENDIAN
 839                 index = 0;
 840                 step = 1;
 841 #else
 842                 index = 3;
 843                 step = -1;
 844 #endif
 845                 break;
 846         case 'l':
 847                 index = 3;
 848                 step = -1;
 849                 break;
 850         case 'n':
 851         case 'b':
 852         default:
 853                 index = 0;
 854                 step = 1;
 855                 break;
 856         }
 857         for (i = 0; i < 4; i++) {
 858                 char temp[3];   /* hold each IP quad in reverse order */
 859                 int digits = put_dec_trunc8(temp, addr[index]) - temp;
 860                 if (leading_zeros) {
 861                         if (digits < 3)
 862                                 *p++ = '0';
 863                         if (digits < 2)
 864                                 *p++ = '0';
 865                 }
 866                 /* reverse the digits in the quad */
 867                 while (digits--)
 868                         *p++ = temp[digits];
 869                 if (i < 3)
 870                         *p++ = '.';
 871                 index += step;
 872         }
 873         *p = '\0';
 874
 875         return p;
 876 }
 877
 878 static noinline_for_stack
 879 char *ip6_compressed_string(char *p, const char *addr)
 880 {
 881         int i, j, range;
 882         unsigned char zerolength[8];
 883         int longest = 1;
 884         int colonpos = -1;
 885         u16 word;
 886         u8 hi, lo;
 887         bool needcolon = false;
 888         bool useIPv4;
 889         struct in6_addr in6;
 890
 891         memcpy(&in6, addr, sizeof(struct in6_addr));
 892
 893         useIPv4 = ipv6_addr_v4mapped(&in6) || ipv6_addr_is_isatap(&in6);
 894
 895         memset(zerolength, 0, sizeof(zerolength));
 896
 897         if (useIPv4)
 898                 range = 6;
 899         else
 900                 range = 8;
 901
 902         /* find position of longest 0 run */
 903         for (i = 0; i < range; i++) {
 904                 for (j = i; j < range; j++) {
 905                         if (in6.s6_addr16[j] != 0)
 906                                 break;
 907                         zerolength[i]++;
 908                 }
 909         }
 910         for (i = 0; i < range; i++) {
 911                 if (zerolength[i] > longest) {
 912                         longest = zerolength[i];
 913                         colonpos = i;
 914                 }
 915         }
 916         if (longest == 1)               /* don't compress a single 0 */
 917                 colonpos = -1;
 918
 919         /* emit address */
 920         for (i = 0; i < range; i++) {
 921                 if (i == colonpos) {
 922                         if (needcolon || i == 0)
 923                                 *p++ = ':';
 924                         *p++ = ':';
 925                         needcolon = false;
 926                         i += longest - 1;
 927                         continue;
 928                 }
 929                 if (needcolon) {
 930                         *p++ = ':';
 931                         needcolon = false;
 932                 }
 933                 /* hex u16 without leading 0s */
 934                 word = ntohs(in6.s6_addr16[i]);
 935                 hi = word >> 8;
 936                 lo = word & 0xff;
 937                 if (hi) {
 938                         if (hi > 0x0f)
 939                                 p = hex_byte_pack(p, hi);
 940                         else
 941                                 *p++ = hex_asc_lo(hi);
 942                         p = hex_byte_pack(p, lo);
 943                 }
 944                 else if (lo > 0x0f)
 945                         p = hex_byte_pack(p, lo);
 946                 else
 947                         *p++ = hex_asc_lo(lo);
 948                 needcolon = true;
 949         }
 950
 951         if (useIPv4) {
 952                 if (needcolon)
 953                         *p++ = ':';
 954                 p = ip4_string(p, &in6.s6_addr[12], "I4");
 955         }
 956         *p = '\0';
 957
 958         return p;
 959 }
 960
 961 static noinline_for_stack
 962 char *ip6_string(char *p, const char *addr, const char *fmt)
 963 {
 964         int i;
 965
 966         for (i = 0; i < 8; i++) {
 967                 p = hex_byte_pack(p, *addr++);
 968                 p = hex_byte_pack(p, *addr++);
 969                 if (fmt[0] == 'I' && i != 7)
 970                         *p++ = ':';
 971         }
 972         *p = '\0';
 973
 974         return p;
 975 }
 976
 977 static noinline_for_stack
 978 char *ip6_addr_string(char *buf, char *end, const u8 *addr,
 979                       struct printf_spec spec, const char *fmt)
 980 {
 981         char ip6_addr[sizeof("xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:255.255.255.255")];
 982
 983         if (fmt[0] == 'I' && fmt[2] == 'c')
 984                 ip6_compressed_string(ip6_addr, addr);
 985         else
 986                 ip6_string(ip6_addr, addr, fmt);
 987
 988         return string(buf, end, ip6_addr, spec);
 989 }
 990
 991 static noinline_for_stack
 992 char *ip4_addr_string(char *buf, char *end, const u8 *addr,
 993                       struct printf_spec spec, const char *fmt)
 994 {
 995         char ip4_addr[sizeof("255.255.255.255")];
 996
 997         ip4_string(ip4_addr, addr, fmt);
 998
 999         return string(buf, end, ip4_addr, spec);
1000 }
1001
1002 static noinline_for_stack
1003 char *ip6_addr_string_sa(char *buf, char *end, const struct sockaddr_in6 *sa,
1004                          struct printf_spec spec, const char *fmt)
1005 {
1006         bool have_p = false, have_s = false, have_f = false, have_c = false;
1007         char ip6_addr[sizeof("[xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:255.255.255.255]") +
1008                       sizeof(":12345") + sizeof("/123456789") +
1009                       sizeof("%1234567890")];
1010         char *p = ip6_addr, *pend = ip6_addr + sizeof(ip6_addr);
1011         const u8 *addr = (const u8 *) &sa->sin6_addr;
1012         char fmt6[2] = { fmt[0], '6' };
1013         u8 off = 0;
1014
1015         fmt++;
1016         while (isalpha(*++fmt)) {
1017                 switch (*fmt) {
1018                 case 'p':
1019                         have_p = true;
1020                         break;
1021                 case 'f':
1022                         have_f = true;
1023                         break;
1024                 case 's':
1025                         have_s = true;
1026                         break;
1027                 case 'c':
1028                         have_c = true;
1029                         break;
1030                 }
1031         }
1032
1033         if (have_p || have_s || have_f) {
1034                 *p = '[';
1035                 off = 1;
1036         }
1037
1038         if (fmt6[0] == 'I' && have_c)
1039                 p = ip6_compressed_string(ip6_addr + off, addr);
1040         else
1041                 p = ip6_string(ip6_addr + off, addr, fmt6);
1042
1043         if (have_p || have_s || have_f)
1044                 *p++ = ']';
1045
1046         if (have_p) {
1047                 *p++ = ':';
1048                 p = number(p, pend, ntohs(sa->sin6_port), spec);
1049         }
1050         if (have_f) {
1051                 *p++ = '/';
1052                 p = number(p, pend, ntohl(sa->sin6_flowinfo &
1053                                           IPV6_FLOWINFO_MASK), spec);
1054         }
1055         if (have_s) {
1056                 *p++ = '%';
1057                 p = number(p, pend, sa->sin6_scope_id, spec);
1058         }
1059         *p = '\0';
1060
1061         return string(buf, end, ip6_addr, spec);
1062 }
1063
1064 static noinline_for_stack
1065 char *ip4_addr_string_sa(char *buf, char *end, const struct sockaddr_in *sa,
1066                          struct printf_spec spec, const char *fmt)
1067 {
1068         bool have_p = false;
1069         char *p, ip4_addr[sizeof("255.255.255.255") + sizeof(":12345")];
1070         char *pend = ip4_addr + sizeof(ip4_addr);
1071         const u8 *addr = (const u8 *) &sa->sin_addr.s_addr;
1072         char fmt4[3] = { fmt[0], '4', 0 };
1073
1074         fmt++;
1075         while (isalpha(*++fmt)) {
1076                 switch (*fmt) {
1077                 case 'p':
1078                         have_p = true;
1079                         break;
1080                 case 'h':
1081                 case 'l':
1082                 case 'n':
1083                 case 'b':
1084                         fmt4[2] = *fmt;
1085                         break;
1086                 }
1087         }
1088
1089         p = ip4_string(ip4_addr, addr, fmt4);
1090         if (have_p) {
1091                 *p++ = ':';
1092                 p = number(p, pend, ntohs(sa->sin_port), spec);
1093         }
1094         *p = '\0';
1095
1096         return string(buf, end, ip4_addr, spec);
1097 }
1098
1099 static noinline_for_stack
1100 char *uuid_string(char *buf, char *end, const u8 *addr,
1101                   struct printf_spec spec, const char *fmt)
1102 {
1103         char uuid[sizeof("xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx")];
1104         char *p = uuid;
1105         int i;
1106         static const u8 be[16] = {0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15};
1107         static const u8 le[16] = {3,2,1,0,5,4,7,6,8,9,10,11,12,13,14,15};
1108         const u8 *index = be;
1109         bool uc = false;
1110
1111         switch (*(++fmt)) {
1112         case 'L':
1113                 uc = true;              /* fall-through */
1114         case 'l':
1115                 index = le;
1116                 break;
1117         case 'B':
1118                 uc = true;
1119                 break;
1120         }
1121
1122         for (i = 0; i < 16; i++) {
1123                 p = hex_byte_pack(p, addr[index[i]]);
1124                 switch (i) {
1125                 case 3:
1126                 case 5:
1127                 case 7:
1128                 case 9:
1129                         *p++ = '-';
1130                         break;
1131                 }
1132         }
1133
1134         *p = 0;
1135
1136         if (uc) {
1137                 p = uuid;
1138                 do {
1139                         *p = toupper(*p);
1140                 } while (*(++p));
1141         }
1142
1143         return string(buf, end, uuid, spec);
1144 }
1145
1146 static
1147 char *netdev_feature_string(char *buf, char *end, const u8 *addr,
1148                       struct printf_spec spec)
1149 {
1150         spec.flags |= SPECIAL | SMALL | ZEROPAD;
1151         if (spec.field_width == -1)
1152                 spec.field_width = 2 + 2 * sizeof(netdev_features_t);
1153         spec.base = 16;
1154
1155         return number(buf, end, *(const netdev_features_t *)addr, spec);
1156 }
1157
1158 int kptr_restrict __read_mostly;
1159
1160 /*
1161  * Show a '%p' thing.  A kernel extension is that the '%p' is followed
1162  * by an extra set of alphanumeric characters that are extended format
1163  * specifiers.
1164  *
1165  * Right now we handle:
1166  *
1167  * - 'F' For symbolic function descriptor pointers with offset
1168  * - 'f' For simple symbolic function names without offset
1169  * - 'S' For symbolic direct pointers with offset
1170  * - 's' For symbolic direct pointers without offset
1171  * - '[FfSs]R' as above with __builtin_extract_return_addr() translation
1172  * - 'B' For backtraced symbolic direct pointers with offset
1173  * - 'R' For decoded struct resource, e.g., [mem 0x0-0x1f 64bit pref]
1174  * - 'r' For raw struct resource, e.g., [mem 0x0-0x1f flags 0x201]
1175  * - 'M' For a 6-byte MAC address, it prints the address in the
1176  *       usual colon-separated hex notation
1177  * - 'm' For a 6-byte MAC address, it prints the hex address without colons
1178  * - 'MF' For a 6-byte MAC FDDI address, it prints the address
1179  *       with a dash-separated hex notation
1180  * - '[mM]R' For a 6-byte MAC address, Reverse order (Bluetooth)
1181  * - 'I' [46] for IPv4/IPv6 addresses printed in the usual way
1182  *       IPv4 uses dot-separated decimal without leading 0's (1.2.3.4)
1183  *       IPv6 uses colon separated network-order 16 bit hex with leading 0's
1184  *       [S][pfs]
1185  *       Generic IPv4/IPv6 address (struct sockaddr *) that falls back to
1186  *       [4] or [6] and is able to print port [p], flowinfo [f], scope [s]
1187  * - 'i' [46] for 'raw' IPv4/IPv6 addresses
1188  *       IPv6 omits the colons (01020304...0f)
1189  *       IPv4 uses dot-separated decimal with leading 0's (010.123.045.006)
1190  *       [S][pfs]
1191  *       Generic IPv4/IPv6 address (struct sockaddr *) that falls back to
1192  *       [4] or [6] and is able to print port [p], flowinfo [f], scope [s]
1193  * - '[Ii][4S][hnbl]' IPv4 addresses in host, network, big or little endian order
1194  * - 'I[6S]c' for IPv6 addresses printed as specified by
1195  *       http://tools.ietf.org/html/rfc5952
1196  * - 'U' For a 16 byte UUID/GUID, it prints the UUID/GUID in the form
1197  *       "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx"
1198  *       Options for %pU are:
1199  *         b big endian lower case hex (default)
1200  *         B big endian UPPER case hex
1201  *         l little endian lower case hex
1202  *         L little endian UPPER case hex
1203  *           big endian output byte order is:
1204  *             [0][1][2][3]-[4][5]-[6][7]-[8][9]-[10][11][12][13][14][15]
1205  *           little endian output byte order is:
1206  *             [3][2][1][0]-[5][4]-[7][6]-[8][9]-[10][11][12][13][14][15]
1207  * - 'V' For a struct va_format which contains a format string * and va_list *,
1208  *       call vsnprintf(->format, *->va_list).
1209  *       Implements a "recursive vsnprintf".
1210  *       Do not use this feature without some mechanism to verify the
1211  *       correctness of the format string and va_list arguments.
1212  * - 'K' For a kernel pointer that should be hidden from unprivileged users
1213  * - 'NF' For a netdev_features_t
1214  * - 'h[CDN]' For a variable-length buffer, it prints it as a hex string with
1215  *            a certain separator (' ' by default):
1216  *              C colon
1217  *              D dash
1218  *              N no separator
1219  *            The maximum supported length is 64 bytes of the input. Consider
1220  *            to use print_hex_dump() for the larger input.
1221  * - 'a' For a phys_addr_t type and its derivative types (passed by reference)
1222  * - 'd[234]' For a dentry name (optionally 2-4 last components)
1223  * - 'D[234]' Same as 'd' but for a struct file
1224  *
1225  * Note: The difference between 'S' and 'F' is that on ia64 and ppc64
1226  * function pointers are really function descriptors, which contain a
1227  * pointer to the real address.
1228  */
1229 static noinline_for_stack
1230 char *pointer(const char *fmt, char *buf, char *end, void *ptr,
1231               struct printf_spec spec)
1232 {
1233         int default_width = 2 * sizeof(void *) + (spec.flags & SPECIAL ? 2 : 0);
1234
1235         if (!ptr && *fmt != 'K') {
1236                 /*
1237                  * Print (null) with the same width as a pointer so it makes
1238                  * tabular output look nice.
1239                  */
1240                 if (spec.field_width == -1)
1241                         spec.field_width = default_width;
1242                 return string(buf, end, "(null)", spec);
1243         }
1244
1245         switch (*fmt) {
1246         case 'F':
1247         case 'f':
1248                 ptr = dereference_function_descriptor(ptr);
1249                 /* Fallthrough */
1250         case 'S':
1251         case 's':
1252         case 'B':
1253                 return symbol_string(buf, end, ptr, spec, fmt);
1254         case 'R':
1255         case 'r':
1256                 return resource_string(buf, end, ptr, spec, fmt);
1257         case 'h':
1258                 return hex_string(buf, end, ptr, spec, fmt);
1259         case 'M':                       /* Colon separated: 00:01:02:03:04:05 */
1260         case 'm':                       /* Contiguous: 000102030405 */
1261                                         /* [mM]F (FDDI) */
1262                                         /* [mM]R (Reverse order; Bluetooth) */
1263                 return mac_address_string(buf, end, ptr, spec, fmt);
1264         case 'I':                       /* Formatted IP supported
1265                                          * 4:   1.2.3.4
1266                                          * 6:   0001:0203:...:0708
1267                                          * 6c:  1::708 or 1::1.2.3.4
1268                                          */
1269         case 'i':                       /* Contiguous:
1270                                          * 4:   001.002.003.004
1271                                          * 6:   000102...0f
1272                                          */
1273                 switch (fmt[1]) {
1274                 case '6':
1275                         return ip6_addr_string(buf, end, ptr, spec, fmt);
1276                 case '4':
1277                         return ip4_addr_string(buf, end, ptr, spec, fmt);
1278                 case 'S': {
1279                         const union {
1280                                 struct sockaddr         raw;
1281                                 struct sockaddr_in      v4;
1282                                 struct sockaddr_in6     v6;
1283                         } *sa = ptr;
1284
1285                         switch (sa->raw.sa_family) {
1286                         case AF_INET:
1287                                 return ip4_addr_string_sa(buf, end, &sa->v4, spec, fmt);
1288                         case AF_INET6:
1289                                 return ip6_addr_string_sa(buf, end, &sa->v6, spec, fmt);
1290                         default:
1291                                 return string(buf, end, "(invalid address)", spec);
1292                         }}
1293                 }
1294                 break;
1295         case 'U':
1296                 return uuid_string(buf, end, ptr, spec, fmt);
1297         case 'V':
1298                 {
1299                         va_list va;
1300
1301                         va_copy(va, *((struct va_format *)ptr)->va);
1302                         buf += vsnprintf(buf, end > buf ? end - buf : 0,
1303                                          ((struct va_format *)ptr)->fmt, va);
1304                         va_end(va);
1305                         return buf;
1306                 }
1307         case 'K':
1308                 /*
1309                  * %pK cannot be used in IRQ context because its test
1310                  * for CAP_SYSLOG would be meaningless.
1311                  */
1312                 if (kptr_restrict && (in_irq() || in_serving_softirq() ||
1313                                       in_nmi())) {
1314                         if (spec.field_width == -1)
1315                                 spec.field_width = default_width;
1316                         return string(buf, end, "pK-error", spec);
1317                 }
1318
1319                 switch (kptr_restrict) {
1320                 case 0:
1321                         /* Always print %pK values */
1322                         break;
1323                 case 1: {
1324                         /*
1325                          * Only print the real pointer value if the current
1326                          * process has CAP_SYSLOG and is running with the
1327                          * same credentials it started with. This is because
1328                          * access to files is checked at open() time, but %pK
1329                          * checks permission at read() time. We don't want to
1330                          * leak pointer values if a binary opens a file using
1331                          * %pK and then elevates privileges before reading it.
1332                          */
1333                         const struct cred *cred = current_cred();
1334
1335                         if (!has_capability_noaudit(current, CAP_SYSLOG) ||
1336                             !uid_eq(cred->euid, cred->uid) ||
1337                             !gid_eq(cred->egid, cred->gid))
1338                                 ptr = NULL;
1339                         break;
1340                 }
1341                 case 2:
1342                 default:
1343                         /* Always print 0's for %pK */
1344                         ptr = NULL;
1345                         break;
1346                 }
1347                 break;
1348
1349         case 'N':
1350                 switch (fmt[1]) {
1351                 case 'F':
1352                         return netdev_feature_string(buf, end, ptr, spec);
1353                 }
1354                 break;
1355         case 'a':
1356                 spec.flags |= SPECIAL | SMALL | ZEROPAD;
1357                 spec.field_width = sizeof(phys_addr_t) * 2 + 2;
1358                 spec.base = 16;
1359                 return number(buf, end,
1360                               (unsigned long long) *((phys_addr_t *)ptr), spec);
1361         case 'd':
1362                 return dentry_name(buf, end, ptr, spec, fmt);
1363         case 'D':
1364                 return dentry_name(buf, end,
1365                                    ((const struct file *)ptr)->f_path.dentry,
1366                                    spec, fmt);
1367         }
1368         spec.flags |= SMALL;
1369         if (spec.field_width == -1) {
1370                 spec.field_width = default_width;
1371                 spec.flags |= ZEROPAD;
1372         }
1373         spec.base = 16;
1374
1375         return number(buf, end, (unsigned long) ptr, spec);
1376 }
1377
1378 /*
1379  * Helper function to decode printf style format.
1380  * Each call decode a token from the format and return the
1381  * number of characters read (or likely the delta where it wants
1382  * to go on the next call).
1383  * The decoded token is returned through the parameters
1384  *
1385  * 'h', 'l', or 'L' for integer fields
1386  * 'z' support added 23/7/1999 S.H.
1387  * 'z' changed to 'Z' --davidm 1/25/99
1388  * 't' added for ptrdiff_t
1389  *
1390  * @fmt: the format string
1391  * @type of the token returned
1392  * @flags: various flags such as +, -, # tokens..
1393  * @field_width: overwritten width
1394  * @base: base of the number (octal, hex, ...)
1395  * @precision: precision of a number
1396  * @qualifier: qualifier of a number (long, size_t, ...)
1397  */
1398 static noinline_for_stack
1399 int format_decode(const char *fmt, struct printf_spec *spec)
1400 {
1401         const char *start = fmt;
1402
1403         /* we finished early by reading the field width */
1404         if (spec->type == FORMAT_TYPE_WIDTH) {
1405                 if (spec->field_width < 0) {
1406                         spec->field_width = -spec->field_width;
1407                         spec->flags |= LEFT;
1408                 }
1409                 spec->type = FORMAT_TYPE_NONE;
1410                 goto precision;
1411         }
1412
1413         /* we finished early by reading the precision */
1414         if (spec->type == FORMAT_TYPE_PRECISION) {
1415                 if (spec->precision < 0)
1416                         spec->precision = 0;
1417
1418                 spec->type = FORMAT_TYPE_NONE;
1419                 goto qualifier;
1420         }
1421
1422         /* By default */
1423         spec->type = FORMAT_TYPE_NONE;
1424
1425         for (; *fmt ; ++fmt) {
1426                 if (*fmt == '%')
1427                         break;
1428         }
1429
1430         /* Return the current non-format string */
1431         if (fmt != start || !*fmt)
1432                 return fmt - start;
1433
1434         /* Process flags */
1435         spec->flags = 0;
1436
1437         while (1) { /* this also skips first '%' */
1438                 bool found = true;
1439
1440                 ++fmt;
1441
1442                 switch (*fmt) {
1443                 case '-': spec->flags |= LEFT;    break;
1444                 case '+': spec->flags |= PLUS;    break;
1445                 case ' ': spec->flags |= SPACE;   break;
1446                 case '#': spec->flags |= SPECIAL; break;
1447                 case '0': spec->flags |= ZEROPAD; break;
1448                 default:  found = false;
1449                 }
1450
1451                 if (!found)
1452                         break;
1453         }
1454
1455         /* get field width */
1456         spec->field_width = -1;
1457
1458         if (isdigit(*fmt))
1459                 spec->field_width = skip_atoi(&fmt);
1460         else if (*fmt == '*') {
1461                 /* it's the next argument */
1462                 spec->type = FORMAT_TYPE_WIDTH;
1463                 return ++fmt - start;
1464         }
1465
1466 precision:
1467         /* get the precision */
1468         spec->precision = -1;
1469         if (*fmt == '.') {
1470                 ++fmt;
1471                 if (isdigit(*fmt)) {
1472                         spec->precision = skip_atoi(&fmt);
1473                         if (spec->precision < 0)
1474                                 spec->precision = 0;
1475                 } else if (*fmt == '*') {
1476                         /* it's the next argument */
1477                         spec->type = FORMAT_TYPE_PRECISION;
1478                         return ++fmt - start;
1479                 }
1480         }
1481
1482 qualifier:
1483         /* get the conversion qualifier */
1484         spec->qualifier = -1;
1485         if (*fmt == 'h' || _tolower(*fmt) == 'l' ||
1486             _tolower(*fmt) == 'z' || *fmt == 't') {
1487                 spec->qualifier = *fmt++;
1488                 if (unlikely(spec->qualifier == *fmt)) {
1489                         if (spec->qualifier == 'l') {
1490                                 spec->qualifier = 'L';
1491                                 ++fmt;
1492                         } else if (spec->qualifier == 'h') {
1493                                 spec->qualifier = 'H';
1494                                 ++fmt;
1495                         }
1496                 }
1497         }
1498
1499         /* default base */
1500         spec->base = 10;
1501         switch (*fmt) {
1502         case 'c':
1503                 spec->type = FORMAT_TYPE_CHAR;
1504                 return ++fmt - start;
1505
1506         case 's':
1507                 spec->type = FORMAT_TYPE_STR;
1508                 return ++fmt - start;
1509
1510         case 'p':
1511                 spec->type = FORMAT_TYPE_PTR;
1512                 return fmt - start;
1513                 /* skip alnum */
1514
1515         case 'n':
1516                 spec->type = FORMAT_TYPE_NRCHARS;
1517                 return ++fmt - start;
1518
1519         case '%':
1520                 spec->type = FORMAT_TYPE_PERCENT_CHAR;
1521                 return ++fmt - start;
1522
1523         /* integer number formats - set up the flags and "break" */
1524         case 'o':
1525                 spec->base = 8;
1526                 break;
1527
1528         case 'x':
1529                 spec->flags |= SMALL;
1530
1531         case 'X':
1532                 spec->base = 16;
1533                 break;
1534
1535         case 'd':
1536         case 'i':
1537                 spec->flags |= SIGN;
1538         case 'u':
1539                 break;
1540
1541         default:
1542                 spec->type = FORMAT_TYPE_INVALID;
1543                 return fmt - start;
1544         }
1545
1546         if (spec->qualifier == 'L')
1547                 spec->type = FORMAT_TYPE_LONG_LONG;
1548         else if (spec->qualifier == 'l') {
1549                 if (spec->flags & SIGN)
1550                         spec->type = FORMAT_TYPE_LONG;
1551                 else
1552                         spec->type = FORMAT_TYPE_ULONG;
1553         } else if (_tolower(spec->qualifier) == 'z') {
1554                 spec->type = FORMAT_TYPE_SIZE_T;
1555         } else if (spec->qualifier == 't') {
1556                 spec->type = FORMAT_TYPE_PTRDIFF;
1557         } else if (spec->qualifier == 'H') {
1558                 if (spec->flags & SIGN)
1559                         spec->type = FORMAT_TYPE_BYTE;
1560                 else
1561                         spec->type = FORMAT_TYPE_UBYTE;
1562         } else if (spec->qualifier == 'h') {
1563                 if (spec->flags & SIGN)
1564                         spec->type = FORMAT_TYPE_SHORT;
1565                 else
1566                         spec->type = FORMAT_TYPE_USHORT;
1567         } else {
1568                 if (spec->flags & SIGN)
1569                         spec->type = FORMAT_TYPE_INT;
1570                 else
1571                         spec->type = FORMAT_TYPE_UINT;
1572         }
1573
1574         return ++fmt - start;
1575 }
1576
1577 /**
1578  * vsnprintf - Format a string and place it in a buffer
1579  * @buf: The buffer to place the result into
1580  * @size: The size of the buffer, including the trailing null space
1581  * @fmt: The format string to use
1582  * @args: Arguments for the format string
1583  *
1584  * This function follows C99 vsnprintf, but has some extensions:
1585  * %pS output the name of a text symbol with offset
1586  * %ps output the name of a text symbol without offset
1587  * %pF output the name of a function pointer with its offset
1588  * %pf output the name of a function pointer without its offset
1589  * %pB output the name of a backtrace symbol with its offset
1590  * %pR output the address range in a struct resource with decoded flags
1591  * %pr output the address range in a struct resource with raw flags
1592  * %pM output a 6-byte MAC address with colons
1593  * %pMR output a 6-byte MAC address with colons in reversed order
1594  * %pMF output a 6-byte MAC address with dashes
1595  * %pm output a 6-byte MAC address without colons
1596  * %pmR output a 6-byte MAC address without colons in reversed order
1597  * %pI4 print an IPv4 address without leading zeros
1598  * %pi4 print an IPv4 address with leading zeros
1599  * %pI6 print an IPv6 address with colons
1600  * %pi6 print an IPv6 address without colons
1601  * %pI6c print an IPv6 address as specified by RFC 5952
1602  * %pIS depending on sa_family of 'struct sockaddr *' print IPv4/IPv6 address
1603  * %piS depending on sa_family of 'struct sockaddr *' print IPv4/IPv6 address
1604  * %pU[bBlL] print a UUID/GUID in big or little endian using lower or upper
1605  *   case.
1606  * %*ph[CDN] a variable-length hex string with a separator (supports up to 64
1607  *           bytes of the input)
1608  * %n is ignored
1609  *
1610  * ** Please update Documentation/printk-formats.txt when making changes **
1611  *
1612  * The return value is the number of characters which would
1613  * be generated for the given input, excluding the trailing
1614  * '\0', as per ISO C99. If you want to have the exact
1615  * number of characters written into @buf as return value
1616  * (not including the trailing '\0'), use vscnprintf(). If the
1617  * return is greater than or equal to @size, the resulting
1618  * string is truncated.
1619  *
1620  * If you're not already dealing with a va_list consider using snprintf().
1621  */
1622 int vsnprintf(char *buf, size_t size, const char *fmt, va_list args)
1623 {
1624         unsigned long long num;
1625         char *str, *end;
1626         struct printf_spec spec = {0};
1627
1628         /* Reject out-of-range values early.  Large positive sizes are
1629            used for unknown buffer sizes. */
1630         if (WARN_ON_ONCE((int) size < 0))
1631                 return 0;
1632
1633         str = buf;
1634         end = buf + size;
1635
1636         /* Make sure end is always >= buf */
1637         if (end < buf) {
1638                 end = ((void *)-1);
1639                 size = end - buf;
1640         }
1641
1642         while (*fmt) {
1643                 const char *old_fmt = fmt;
1644                 int read = format_decode(fmt, &spec);
1645
1646                 fmt += read;
1647
1648                 switch (spec.type) {
1649                 case FORMAT_TYPE_NONE: {
1650                         int copy = read;
1651                         if (str < end) {
1652                                 if (copy > end - str)
1653                                         copy = end - str;
1654                                 memcpy(str, old_fmt, copy);
1655                         }
1656                         str += read;
1657                         break;
1658                 }
1659
1660                 case FORMAT_TYPE_WIDTH:
1661                         spec.field_width = va_arg(args, int);
1662                         break;
1663
1664                 case FORMAT_TYPE_PRECISION:
1665                         spec.precision = va_arg(args, int);
1666                         break;
1667
1668                 case FORMAT_TYPE_CHAR: {
1669                         char c;
1670
1671                         if (!(spec.flags & LEFT)) {
1672                                 while (--spec.field_width > 0) {
1673                                         if (str < end)
1674                                                 *str = ' ';
1675                                         ++str;
1676
1677                                 }
1678                         }
1679                         c = (unsigned char) va_arg(args, int);
1680                         if (str < end)
1681                                 *str = c;
1682                         ++str;
1683                         while (--spec.field_width > 0) {
1684                                 if (str < end)
1685                                         *str = ' ';
1686                                 ++str;
1687                         }
1688                         break;
1689                 }
1690
1691                 case FORMAT_TYPE_STR:
1692                         str = string(str, end, va_arg(args, char *), spec);
1693                         break;
1694
1695                 case FORMAT_TYPE_PTR:
1696                         str = pointer(fmt+1, str, end, va_arg(args, void *),
1697                                       spec);
1698                         while (isalnum(*fmt))
1699                                 fmt++;
1700                         break;
1701
1702                 case FORMAT_TYPE_PERCENT_CHAR:
1703                         if (str < end)
1704                                 *str = '%';
1705                         ++str;
1706                         break;
1707
1708                 case FORMAT_TYPE_INVALID:
1709                         if (str < end)
1710                                 *str = '%';
1711                         ++str;
1712                         break;
1713
1714                 case FORMAT_TYPE_NRCHARS: {
1715                         /*
1716                          * Since %n poses a greater security risk than
1717                          * utility, ignore %n and skip its argument.
1718                          */
1719                         void *skip_arg;
1720
1721                         WARN_ONCE(1, "Please remove ignored %%n in '%s'\n",
1722                                         old_fmt);
1723
1724                         skip_arg = va_arg(args, void *);
1725                         break;
1726                 }
1727
1728                 default:
1729                         switch (spec.type) {
1730                         case FORMAT_TYPE_LONG_LONG:
1731                                 num = va_arg(args, long long);
1732                                 break;
1733                         case FORMAT_TYPE_ULONG:
1734                                 num = va_arg(args, unsigned long);
1735                                 break;
1736                         case FORMAT_TYPE_LONG:
1737                                 num = va_arg(args, long);
1738                                 break;
1739                         case FORMAT_TYPE_SIZE_T:
1740                                 if (spec.flags & SIGN)
1741                                         num = va_arg(args, ssize_t);
1742                                 else
1743                                         num = va_arg(args, size_t);
1744                                 break;
1745                         case FORMAT_TYPE_PTRDIFF:
1746                                 num = va_arg(args, ptrdiff_t);
1747                                 break;
1748                         case FORMAT_TYPE_UBYTE:
1749                                 num = (unsigned char) va_arg(args, int);
1750                                 break;
1751                         case FORMAT_TYPE_BYTE:
1752                                 num = (signed char) va_arg(args, int);
1753                                 break;
1754                         case FORMAT_TYPE_USHORT:
1755                                 num = (unsigned short) va_arg(args, int);
1756                                 break;
1757                         case FORMAT_TYPE_SHORT:
1758                                 num = (short) va_arg(args, int);
1759                                 break;
1760                         case FORMAT_TYPE_INT:
1761                                 num = (int) va_arg(args, int);
1762                                 break;
1763                         default:
1764                                 num = va_arg(args, unsigned int);
1765                         }
1766
1767                         str = number(str, end, num, spec);
1768                 }
1769         }
1770
1771         if (size > 0) {
1772                 if (str < end)
1773                         *str = '\0';
1774                 else
1775                         end[-1] = '\0';
1776         }
1777
1778         /* the trailing null byte doesn't count towards the total */
1779         return str-buf;
1780
1781 }
1782 EXPORT_SYMBOL(vsnprintf);
1783
1784 /**
1785  * vscnprintf - Format a string and place it in a buffer
1786  * @buf: The buffer to place the result into
1787  * @size: The size of the buffer, including the trailing null space
1788  * @fmt: The format string to use
1789  * @args: Arguments for the format string
1790  *
1791  * The return value is the number of characters which have been written into
1792  * the @buf not including the trailing '\0'. If @size is == 0 the function
1793  * returns 0.
1794  *
1795  * If you're not already dealing with a va_list consider using scnprintf().
1796  *
1797  * See the vsnprintf() documentation for format string extensions over C99.
1798  */
1799 int vscnprintf(char *buf, size_t size, const char *fmt, va_list args)
1800 {
1801         int i;
1802
1803         i = vsnprintf(buf, size, fmt, args);
1804
1805         if (likely(i < size))
1806                 return i;
1807         if (size != 0)
1808                 return size - 1;
1809         return 0;
1810 }
1811 EXPORT_SYMBOL(vscnprintf);
1812
1813 /**
1814  * snprintf - Format a string and place it in a buffer
1815  * @buf: The buffer to place the result into
1816  * @size: The size of the buffer, including the trailing null space
1817  * @fmt: The format string to use
1818  * @...: Arguments for the format string
1819  *
1820  * The return value is the number of characters which would be
1821  * generated for the given input, excluding the trailing null,
1822  * as per ISO C99.  If the return is greater than or equal to
1823  * @size, the resulting string is truncated.
1824  *
1825  * See the vsnprintf() documentation for format string extensions over C99.
1826  */
1827 int snprintf(char *buf, size_t size, const char *fmt, ...)
1828 {
1829         va_list args;
1830         int i;
1831
1832         va_start(args, fmt);
1833         i = vsnprintf(buf, size, fmt, args);
1834         va_end(args);
1835
1836         return i;
1837 }
1838 EXPORT_SYMBOL(snprintf);
1839
1840 /**
1841  * scnprintf - Format a string and place it in a buffer
1842  * @buf: The buffer to place the result into
1843  * @size: The size of the buffer, including the trailing null space
1844  * @fmt: The format string to use
1845  * @...: Arguments for the format string
1846  *
1847  * The return value is the number of characters written into @buf not including
1848  * the trailing '\0'. If @size is == 0 the function returns 0.
1849  */
1850
1851 int scnprintf(char *buf, size_t size, const char *fmt, ...)
1852 {
1853         va_list args;
1854         int i;
1855
1856         va_start(args, fmt);
1857         i = vscnprintf(buf, size, fmt, args);
1858         va_end(args);
1859
1860         return i;
1861 }
1862 EXPORT_SYMBOL(scnprintf);
1863
1864 /**
1865  * vsprintf - Format a string and place it in a buffer
1866  * @buf: The buffer to place the result into
1867  * @fmt: The format string to use
1868  * @args: Arguments for the format string
1869  *
1870  * The function returns the number of characters written
1871  * into @buf. Use vsnprintf() or vscnprintf() in order to avoid
1872  * buffer overflows.
1873  *
1874  * If you're not already dealing with a va_list consider using sprintf().
1875  *
1876  * See the vsnprintf() documentation for format string extensions over C99.
1877  */
1878 int vsprintf(char *buf, const char *fmt, va_list args)
1879 {
1880         return vsnprintf(buf, INT_MAX, fmt, args);
1881 }
1882 EXPORT_SYMBOL(vsprintf);
1883
1884 /**
1885  * sprintf - Format a string and place it in a buffer
1886  * @buf: The buffer to place the result into
1887  * @fmt: The format string to use
1888  * @...: Arguments for the format string
1889  *
1890  * The function returns the number of characters written
1891  * into @buf. Use snprintf() or scnprintf() in order to avoid
1892  * buffer overflows.
1893  *
1894  * See the vsnprintf() documentation for format string extensions over C99.
1895  */
1896 int sprintf(char *buf, const char *fmt, ...)
1897 {
1898         va_list args;
1899         int i;
1900
1901         va_start(args, fmt);
1902         i = vsnprintf(buf, INT_MAX, fmt, args);
1903         va_end(args);
1904
1905         return i;
1906 }
1907 EXPORT_SYMBOL(sprintf);
1908
1909 #ifdef CONFIG_BINARY_PRINTF
1910 /*
1911  * bprintf service:
1912  * vbin_printf() - VA arguments to binary data
1913  * bstr_printf() - Binary data to text string
1914  */
1915
1916 /**
1917  * vbin_printf - Parse a format string and place args' binary value in a buffer
1918  * @bin_buf: The buffer to place args' binary value
1919  * @size: The size of the buffer(by words(32bits), not characters)
1920  * @fmt: The format string to use
1921  * @args: Arguments for the format string
1922  *
1923  * The format follows C99 vsnprintf, except %n is ignored, and its argument
1924  * is skiped.
1925  *
1926  * The return value is the number of words(32bits) which would be generated for
1927  * the given input.
1928  *
1929  * NOTE:
1930  * If the return value is greater than @size, the resulting bin_buf is NOT
1931  * valid for bstr_printf().
1932  */
1933 int vbin_printf(u32 *bin_buf, size_t size, const char *fmt, va_list args)
1934 {
1935         struct printf_spec spec = {0};
1936         char *str, *end;
1937
1938         str = (char *)bin_buf;
1939         end = (char *)(bin_buf + size);
1940
1941 #define save_arg(type)                                                  \
1942 do {                                                                    \
1943         if (sizeof(type) == 8) {                                        \
1944                 unsigned long long value;                               \
1945                 str = PTR_ALIGN(str, sizeof(u32));                      \
1946                 value = va_arg(args, unsigned long long);               \
1947                 if (str + sizeof(type) <= end) {                        \
1948                         *(u32 *)str = *(u32 *)&value;                   \
1949                         *(u32 *)(str + 4) = *((u32 *)&value + 1);       \
1950                 }                                                       \
1951         } else {                                                        \
1952                 unsigned long value;                                    \
1953                 str = PTR_ALIGN(str, sizeof(type));                     \
1954                 value = va_arg(args, int);                              \
1955                 if (str + sizeof(type) <= end)                          \
1956                         *(typeof(type) *)str = (type)value;             \
1957         }                                                               \
1958         str += sizeof(type);                                            \
1959 } while (0)
1960
1961         while (*fmt) {
1962                 int read = format_decode(fmt, &spec);
1963
1964                 fmt += read;
1965
1966                 switch (spec.type) {
1967                 case FORMAT_TYPE_NONE:
1968                 case FORMAT_TYPE_INVALID:
1969                 case FORMAT_TYPE_PERCENT_CHAR:
1970                         break;
1971
1972                 case FORMAT_TYPE_WIDTH:
1973                 case FORMAT_TYPE_PRECISION:
1974                         save_arg(int);
1975                         break;
1976
1977                 case FORMAT_TYPE_CHAR:
1978                         save_arg(char);
1979                         break;
1980
1981                 case FORMAT_TYPE_STR: {
1982                         const char *save_str = va_arg(args, char *);
1983                         size_t len;
1984
1985                         if ((unsigned long)save_str > (unsigned long)-PAGE_SIZE
1986                                         || (unsigned long)save_str < PAGE_SIZE)
1987                                 save_str = "(null)";
1988                         len = strlen(save_str) + 1;
1989                         if (str + len < end)
1990                                 memcpy(str, save_str, len);
1991                         str += len;
1992                         break;
1993                 }
1994
1995                 case FORMAT_TYPE_PTR:
1996                         save_arg(void *);
1997                         /* skip all alphanumeric pointer suffixes */
1998                         while (isalnum(*fmt))
1999                                 fmt++;
2000                         break;
2001
2002                 case FORMAT_TYPE_NRCHARS: {
2003                         /* skip %n 's argument */
2004                         u8 qualifier = spec.qualifier;
2005                         void *skip_arg;
2006                         if (qualifier == 'l')
2007                                 skip_arg = va_arg(args, long *);
2008                         else if (_tolower(qualifier) == 'z')
2009                                 skip_arg = va_arg(args, size_t *);
2010                         else
2011                                 skip_arg = va_arg(args, int *);
2012                         break;
2013                 }
2014
2015                 default:
2016                         switch (spec.type) {
2017
2018                         case FORMAT_TYPE_LONG_LONG:
2019                                 save_arg(long long);
2020                                 break;
2021                         case FORMAT_TYPE_ULONG:
2022                         case FORMAT_TYPE_LONG:
2023                                 save_arg(unsigned long);
2024                                 break;
2025                         case FORMAT_TYPE_SIZE_T:
2026                                 save_arg(size_t);
2027                                 break;
2028                         case FORMAT_TYPE_PTRDIFF:
2029                                 save_arg(ptrdiff_t);
2030                                 break;
2031                         case FORMAT_TYPE_UBYTE:
2032                         case FORMAT_TYPE_BYTE:
2033                                 save_arg(char);
2034                                 break;
2035                         case FORMAT_TYPE_USHORT:
2036                         case FORMAT_TYPE_SHORT:
2037                                 save_arg(short);
2038                                 break;
2039                         default:
2040                                 save_arg(int);
2041                         }
2042                 }
2043         }
2044
2045         return (u32 *)(PTR_ALIGN(str, sizeof(u32))) - bin_buf;
2046 #undef save_arg
2047 }
2048 EXPORT_SYMBOL_GPL(vbin_printf);
2049
2050 /**
2051  * bstr_printf - Format a string from binary arguments and place it in a buffer
2052  * @buf: The buffer to place the result into
2053  * @size: The size of the buffer, including the trailing null space
2054  * @fmt: The format string to use
2055  * @bin_buf: Binary arguments for the format string
2056  *
2057  * This function like C99 vsnprintf, but the difference is that vsnprintf gets
2058  * arguments from stack, and bstr_printf gets arguments from @bin_buf which is
2059  * a binary buffer that generated by vbin_printf.
2060  *
2061  * The format follows C99 vsnprintf, but has some extensions:
2062  *  see vsnprintf comment for details.
2063  *
2064  * The return value is the number of characters which would
2065  * be generated for the given input, excluding the trailing
2066  * '\0', as per ISO C99. If you want to have the exact
2067  * number of characters written into @buf as return value
2068  * (not including the trailing '\0'), use vscnprintf(). If the
2069  * return is greater than or equal to @size, the resulting
2070  * string is truncated.
2071  */
2072 int bstr_printf(char *buf, size_t size, const char *fmt, const u32 *bin_buf)
2073 {
2074         struct printf_spec spec = {0};
2075         char *str, *end;
2076         const char *args = (const char *)bin_buf;
2077
2078         if (WARN_ON_ONCE((int) size < 0))
2079                 return 0;
2080
2081         str = buf;
2082         end = buf + size;
2083
2084 #define get_arg(type)                                                   \
2085 ({                                                                      \
2086         typeof(type) value;                                             \
2087         if (sizeof(type) == 8) {                                        \
2088                 args = PTR_ALIGN(args, sizeof(u32));                    \
2089                 *(u32 *)&value = *(u32 *)args;                          \
2090                 *((u32 *)&value + 1) = *(u32 *)(args + 4);              \
2091         } else {                                                        \
2092                 args = PTR_ALIGN(args, sizeof(type));                   \
2093                 value = *(typeof(type) *)args;                          \
2094         }                                                               \
2095         args += sizeof(type);                                           \
2096         value;                                                          \
2097 })
2098
2099         /* Make sure end is always >= buf */
2100         if (end < buf) {
2101                 end = ((void *)-1);
2102                 size = end - buf;
2103         }
2104
2105         while (*fmt) {
2106                 const char *old_fmt = fmt;
2107                 int read = format_decode(fmt, &spec);
2108
2109                 fmt += read;
2110
2111                 switch (spec.type) {
2112                 case FORMAT_TYPE_NONE: {
2113                         int copy = read;
2114                         if (str < end) {
2115                                 if (copy > end - str)
2116                                         copy = end - str;
2117                                 memcpy(str, old_fmt, copy);
2118                         }
2119                         str += read;
2120                         break;
2121                 }
2122
2123                 case FORMAT_TYPE_WIDTH:
2124                         spec.field_width = get_arg(int);
2125                         break;
2126
2127                 case FORMAT_TYPE_PRECISION:
2128                         spec.precision = get_arg(int);
2129                         break;
2130
2131                 case FORMAT_TYPE_CHAR: {
2132                         char c;
2133
2134                         if (!(spec.flags & LEFT)) {
2135                                 while (--spec.field_width > 0) {
2136                                         if (str < end)
2137                                                 *str = ' ';
2138                                         ++str;
2139                                 }
2140                         }
2141                         c = (unsigned char) get_arg(char);
2142                         if (str < end)
2143                                 *str = c;
2144                         ++str;
2145                         while (--spec.field_width > 0) {
2146                                 if (str < end)
2147                                         *str = ' ';
2148                                 ++str;
2149                         }
2150                         break;
2151                 }
2152
2153                 case FORMAT_TYPE_STR: {
2154                         const char *str_arg = args;
2155                         args += strlen(str_arg) + 1;
2156                         str = string(str, end, (char *)str_arg, spec);
2157                         break;
2158                 }
2159
2160                 case FORMAT_TYPE_PTR:
2161                         str = pointer(fmt+1, str, end, get_arg(void *), spec);
2162                         while (isalnum(*fmt))
2163                                 fmt++;
2164                         break;
2165
2166                 case FORMAT_TYPE_PERCENT_CHAR:
2167                 case FORMAT_TYPE_INVALID:
2168                         if (str < end)
2169                                 *str = '%';
2170                         ++str;
2171                         break;
2172
2173                 case FORMAT_TYPE_NRCHARS:
2174                         /* skip */
2175                         break;
2176
2177                 default: {
2178                         unsigned long long num;
2179
2180                         switch (spec.type) {
2181
2182                         case FORMAT_TYPE_LONG_LONG:
2183                                 num = get_arg(long long);
2184                                 break;
2185                         case FORMAT_TYPE_ULONG:
2186                         case FORMAT_TYPE_LONG:
2187                                 num = get_arg(unsigned long);
2188                                 break;
2189                         case FORMAT_TYPE_SIZE_T:
2190                                 num = get_arg(size_t);
2191                                 break;
2192                         case FORMAT_TYPE_PTRDIFF:
2193                                 num = get_arg(ptrdiff_t);
2194                                 break;
2195                         case FORMAT_TYPE_UBYTE:
2196                                 num = get_arg(unsigned char);
2197                                 break;
2198                         case FORMAT_TYPE_BYTE:
2199                                 num = get_arg(signed char);
2200                                 break;
2201                         case FORMAT_TYPE_USHORT:
2202                                 num = get_arg(unsigned short);
2203                                 break;
2204                         case FORMAT_TYPE_SHORT:
2205                                 num = get_arg(short);
2206                                 break;
2207                         case FORMAT_TYPE_UINT:
2208                                 num = get_arg(unsigned int);
2209                                 break;
2210                         default:
2211                                 num = get_arg(int);
2212                         }
2213
2214                         str = number(str, end, num, spec);
2215                 } /* default: */
2216                 } /* switch(spec.type) */
2217         } /* while(*fmt) */
2218
2219         if (size > 0) {
2220                 if (str < end)
2221                         *str = '\0';
2222                 else
2223                         end[-1] = '\0';
2224         }
2225
2226 #undef get_arg
2227
2228         /* the trailing null byte doesn't count towards the total */
2229         return str - buf;
2230 }
2231 EXPORT_SYMBOL_GPL(bstr_printf);
2232
2233 /**
2234  * bprintf - Parse a format string and place args' binary value in a buffer
2235  * @bin_buf: The buffer to place args' binary value
2236  * @size: The size of the buffer(by words(32bits), not characters)
2237  * @fmt: The format string to use
2238  * @...: Arguments for the format string
2239  *
2240  * The function returns the number of words(u32) written
2241  * into @bin_buf.
2242  */
2243 int bprintf(u32 *bin_buf, size_t size, const char *fmt, ...)
2244 {
2245         va_list args;
2246         int ret;
2247
2248         va_start(args, fmt);
2249         ret = vbin_printf(bin_buf, size, fmt, args);
2250         va_end(args);
2251
2252         return ret;
2253 }
2254 EXPORT_SYMBOL_GPL(bprintf);
2255
2256 #endif /* CONFIG_BINARY_PRINTF */
2257
2258 /**
2259  * vsscanf - Unformat a buffer into a list of arguments
2260  * @buf:        input buffer
2261  * @fmt:        format of buffer
2262  * @args:       arguments
2263  */
2264 int vsscanf(const char *buf, const char *fmt, va_list args)
2265 {
2266         const char *str = buf;
2267         char *next;
2268         char digit;
2269         int num = 0;
2270         u8 qualifier;
2271         unsigned int base;
2272         union {
2273                 long long s;
2274                 unsigned long long u;
2275         } val;
2276         s16 field_width;
2277         bool is_sign;
2278
2279         while (*fmt) {
2280                 /* skip any white space in format */
2281                 /* white space in format matchs any amount of
2282                  * white space, including none, in the input.
2283                  */
2284                 if (isspace(*fmt)) {
2285                         fmt = skip_spaces(++fmt);
2286                         str = skip_spaces(str);
2287                 }
2288
2289                 /* anything that is not a conversion must match exactly */
2290                 if (*fmt != '%' && *fmt) {
2291                         if (*fmt++ != *str++)
2292                                 break;
2293                         continue;
2294                 }
2295
2296                 if (!*fmt)
2297                         break;
2298                 ++fmt;
2299
2300                 /* skip this conversion.
2301                  * advance both strings to next white space
2302                  */
2303                 if (*fmt == '*') {
2304                         if (!*str)
2305                                 break;
2306                         while (!isspace(*fmt) && *fmt != '%' && *fmt)
2307                                 fmt++;
2308                         while (!isspace(*str) && *str)
2309                                 str++;
2310                         continue;
2311                 }
2312
2313                 /* get field width */
2314                 field_width = -1;
2315                 if (isdigit(*fmt)) {
2316                         field_width = skip_atoi(&fmt);
2317                         if (field_width <= 0)
2318                                 break;
2319                 }
2320
2321                 /* get conversion qualifier */
2322                 qualifier = -1;
2323                 if (*fmt == 'h' || _tolower(*fmt) == 'l' ||
2324                     _tolower(*fmt) == 'z') {
2325                         qualifier = *fmt++;
2326                         if (unlikely(qualifier == *fmt)) {
2327                                 if (qualifier == 'h') {
2328                                         qualifier = 'H';
2329                                         fmt++;
2330                                 } else if (qualifier == 'l') {
2331                                         qualifier = 'L';
2332                                         fmt++;
2333                                 }
2334                         }
2335                 }
2336
2337                 if (!*fmt)
2338                         break;
2339
2340                 if (*fmt == 'n') {
2341                         /* return number of characters read so far */
2342                         *va_arg(args, int *) = str - buf;
2343                         ++fmt;
2344                         continue;
2345                 }
2346
2347                 if (!*str)
2348                         break;
2349
2350                 base = 10;
2351                 is_sign = 0;
2352
2353                 switch (*fmt++) {
2354                 case 'c':
2355                 {
2356                         char *s = (char *)va_arg(args, char*);
2357                         if (field_width == -1)
2358                                 field_width = 1;
2359                         do {
2360                                 *s++ = *str++;
2361                         } while (--field_width > 0 && *str);
2362                         num++;
2363                 }
2364                 continue;
2365                 case 's':
2366                 {
2367                         char *s = (char *)va_arg(args, char *);
2368                         if (field_width == -1)
2369                                 field_width = SHRT_MAX;
2370                         /* first, skip leading white space in buffer */
2371                         str = skip_spaces(str);
2372
2373                         /* now copy until next white space */
2374                         while (*str && !isspace(*str) && field_width--)
2375                                 *s++ = *str++;
2376                         *s = '\0';
2377                         num++;
2378                 }
2379                 continue;
2380                 case 'o':
2381                         base = 8;
2382                         break;
2383                 case 'x':
2384                 case 'X':
2385                         base = 16;
2386                         break;
2387                 case 'i':
2388                         base = 0;
2389                 case 'd':
2390                         is_sign = 1;
2391                 case 'u':
2392                         break;
2393                 case '%':
2394                         /* looking for '%' in str */
2395                         if (*str++ != '%')
2396                                 return num;
2397                         continue;
2398                 default:
2399                         /* invalid format; stop here */
2400                         return num;
2401                 }
2402
2403                 /* have some sort of integer conversion.
2404                  * first, skip white space in buffer.
2405                  */
2406                 str = skip_spaces(str);
2407
2408                 digit = *str;
2409                 if (is_sign && digit == '-')
2410                         digit = *(str + 1);
2411
2412                 if (!digit
2413                     || (base == 16 && !isxdigit(digit))
2414                     || (base == 10 && !isdigit(digit))
2415                     || (base == 8 && (!isdigit(digit) || digit > '7'))
2416                     || (base == 0 && !isdigit(digit)))
2417                         break;
2418
2419                 if (is_sign)
2420                         val.s = qualifier != 'L' ?
2421                                 simple_strtol(str, &next, base) :
2422                                 simple_strtoll(str, &next, base);
2423                 else
2424                         val.u = qualifier != 'L' ?
2425                                 simple_strtoul(str, &next, base) :
2426                                 simple_strtoull(str, &next, base);
2427
2428                 if (field_width > 0 && next - str > field_width) {
2429                         if (base == 0)
2430                                 _parse_integer_fixup_radix(str, &base);
2431                         while (next - str > field_width) {
2432                                 if (is_sign)
2433                                         val.s = div_s64(val.s, base);
2434                                 else
2435                                         val.u = div_u64(val.u, base);
2436                                 --next;
2437                         }
2438                 }
2439
2440                 switch (qualifier) {
2441                 case 'H':       /* that's 'hh' in format */
2442                         if (is_sign)
2443                                 *va_arg(args, signed char *) = val.s;
2444                         else
2445                                 *va_arg(args, unsigned char *) = val.u;
2446                         break;
2447                 case 'h':
2448                         if (is_sign)
2449                                 *va_arg(args, short *) = val.s;
2450                         else
2451                                 *va_arg(args, unsigned short *) = val.u;
2452                         break;
2453                 case 'l':
2454                         if (is_sign)
2455                                 *va_arg(args, long *) = val.s;
2456                         else
2457                                 *va_arg(args, unsigned long *) = val.u;
2458                         break;
2459                 case 'L':
2460                         if (is_sign)
2461                                 *va_arg(args, long long *) = val.s;
2462                         else
2463                                 *va_arg(args, unsigned long long *) = val.u;
2464                         break;
2465                 case 'Z':
2466                 case 'z':
2467                         *va_arg(args, size_t *) = val.u;
2468                         break;
2469                 default:
2470                         if (is_sign)
2471                                 *va_arg(args, int *) = val.s;
2472                         else
2473                                 *va_arg(args, unsigned int *) = val.u;
2474                         break;
2475                 }
2476                 num++;
2477
2478                 if (!next)
2479                         break;
2480                 str = next;
2481         }
2482
2483         return num;
2484 }
2485 EXPORT_SYMBOL(vsscanf);
2486
2487 /**
2488  * sscanf - Unformat a buffer into a list of arguments
2489  * @buf:        input buffer
2490  * @fmt:        formatting of buffer
2491  * @...:        resulting arguments
2492  */
2493 int sscanf(const char *buf, const char *fmt, ...)
2494 {
2495         va_list args;
2496         int i;
2497
2498         va_start(args, fmt);
2499         i = vsscanf(buf, fmt, args);
2500         va_end(args);
2501
2502         return i;
2503 }
2504 EXPORT_SYMBOL(sscanf);