lib/vsprintf.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *  linux/lib/vsprintf.c
   4  *
   5  *  Copyright (C) 1991, 1992  Linus Torvalds
   6  */
   7
   8 /* vsprintf.c -- Lars Wirzenius & Linus Torvalds. */
   9 /*
  10  * Wirzenius wrote this portably, Torvalds fucked it up :-)
  11  */
  12
  13 /*
  14  * Fri Jul 13 2001 Crutcher Dunnavant <crutcher+kernel@datastacks.com>
  15  * - changed to provide snprintf and vsnprintf functions
  16  * So Feb  1 16:51:32 CET 2004 Juergen Quade <quade@hsnr.de>
  17  * - scnprintf and vscnprintf
  18  */
  19
  20 #include <linux/stdarg.h>
  21 #include <linux/build_bug.h>
  22 #include <linux/clk.h>
  23 #include <linux/clk-provider.h>
  24 #include <linux/errname.h>
  25 #include <linux/module.h>       /* for KSYM_SYMBOL_LEN */
  26 #include <linux/types.h>
  27 #include <linux/string.h>
  28 #include <linux/ctype.h>
  29 #include <linux/kernel.h>
  30 #include <linux/kallsyms.h>
  31 #include <linux/math64.h>
  32 #include <linux/uaccess.h>
  33 #include <linux/ioport.h>
  34 #include <linux/dcache.h>
  35 #include <linux/cred.h>
  36 #include <linux/rtc.h>
  37 #include <linux/sprintf.h>
  38 #include <linux/time.h>
  39 #include <linux/uuid.h>
  40 #include <linux/of.h>
  41 #include <net/addrconf.h>
  42 #include <linux/siphash.h>
  43 #include <linux/compiler.h>
  44 #include <linux/property.h>
  45 #include <linux/notifier.h>
  46 #ifdef CONFIG_BLOCK
  47 #include <linux/blkdev.h>
  48 #endif
  49
  50 #include "../mm/internal.h"     /* For the trace_print_flags arrays */
  51
  52 #include <asm/page.h>           /* for PAGE_SIZE */
  53 #include <asm/byteorder.h>      /* cpu_to_le16 */
  54 #include <asm/unaligned.h>
  55
  56 #include <linux/string_helpers.h>
  57 #include "kstrtox.h"
  58
  59 /* Disable pointer hashing if requested */
  60 bool no_hash_pointers __ro_after_init;
  61 EXPORT_SYMBOL_GPL(no_hash_pointers);
  62
  63 noinline
  64 static unsigned long long simple_strntoull(const char *startp, char **endp, unsigned int base, size_t max_chars)
  65 {
  66         const char *cp;
  67         unsigned long long result = 0ULL;
  68         size_t prefix_chars;
  69         unsigned int rv;
  70
  71         cp = _parse_integer_fixup_radix(startp, &base);
  72         prefix_chars = cp - startp;
  73         if (prefix_chars < max_chars) {
  74                 rv = _parse_integer_limit(cp, base, &result, max_chars - prefix_chars);
  75                 /* FIXME */
  76                 cp += (rv & ~KSTRTOX_OVERFLOW);
  77         } else {
  78                 /* Field too short for prefix + digit, skip over without converting */
  79                 cp = startp + max_chars;
  80         }
  81
  82         if (endp)
  83                 *endp = (char *)cp;
  84
  85         return result;
  86 }
  87
  88 /**
  89  * simple_strtoull - convert a string to an unsigned long long
  90  * @cp: The start of the string
  91  * @endp: A pointer to the end of the parsed string will be placed here
  92  * @base: The number base to use
  93  *
  94  * This function has caveats. Please use kstrtoull instead.
  95  */
  96 noinline
  97 unsigned long long simple_strtoull(const char *cp, char **endp, unsigned int base)
  98 {
  99         return simple_strntoull(cp, endp, base, INT_MAX);
 100 }
 101 EXPORT_SYMBOL(simple_strtoull);
 102
 103 /**
 104  * simple_strtoul - convert a string to an unsigned long
 105  * @cp: The start of the string
 106  * @endp: A pointer to the end of the parsed string will be placed here
 107  * @base: The number base to use
 108  *
 109  * This function has caveats. Please use kstrtoul instead.
 110  */
 111 unsigned long simple_strtoul(const char *cp, char **endp, unsigned int base)
 112 {
 113         return simple_strtoull(cp, endp, base);
 114 }
 115 EXPORT_SYMBOL(simple_strtoul);
 116
 117 /**
 118  * simple_strtol - convert a string to a signed long
 119  * @cp: The start of the string
 120  * @endp: A pointer to the end of the parsed string will be placed here
 121  * @base: The number base to use
 122  *
 123  * This function has caveats. Please use kstrtol instead.
 124  */
 125 long simple_strtol(const char *cp, char **endp, unsigned int base)
 126 {
 127         if (*cp == '-')
 128                 return -simple_strtoul(cp + 1, endp, base);
 129
 130         return simple_strtoul(cp, endp, base);
 131 }
 132 EXPORT_SYMBOL(simple_strtol);
 133
 134 noinline
 135 static long long simple_strntoll(const char *cp, char **endp, unsigned int base, size_t max_chars)
 136 {
 137         /*
 138          * simple_strntoull() safely handles receiving max_chars==0 in the
 139          * case cp[0] == '-' && max_chars == 1.
 140          * If max_chars == 0 we can drop through and pass it to simple_strntoull()
 141          * and the content of *cp is irrelevant.
 142          */
 143         if (*cp == '-' && max_chars > 0)
 144                 return -simple_strntoull(cp + 1, endp, base, max_chars - 1);
 145
 146         return simple_strntoull(cp, endp, base, max_chars);
 147 }
 148
 149 /**
 150  * simple_strtoll - convert a string to a signed long long
 151  * @cp: The start of the string
 152  * @endp: A pointer to the end of the parsed string will be placed here
 153  * @base: The number base to use
 154  *
 155  * This function has caveats. Please use kstrtoll instead.
 156  */
 157 long long simple_strtoll(const char *cp, char **endp, unsigned int base)
 158 {
 159         return simple_strntoll(cp, endp, base, INT_MAX);
 160 }
 161 EXPORT_SYMBOL(simple_strtoll);
 162
 163 static noinline_for_stack
 164 int skip_atoi(const char **s)
 165 {
 166         int i = 0;
 167
 168         do {
 169                 i = i*10 + *((*s)++) - '0';
 170         } while (isdigit(**s));
 171
 172         return i;
 173 }
 174
 175 /*
 176  * Decimal conversion is by far the most typical, and is used for
 177  * /proc and /sys data. This directly impacts e.g. top performance
 178  * with many processes running. We optimize it for speed by emitting
 179  * two characters at a time, using a 200 byte lookup table. This
 180  * roughly halves the number of multiplications compared to computing
 181  * the digits one at a time. Implementation strongly inspired by the
 182  * previous version, which in turn used ideas described at
 183  * <http://www.cs.uiowa.edu/~jones/bcd/divide.html> (with permission
 184  * from the author, Douglas W. Jones).
 185  *
 186  * It turns out there is precisely one 26 bit fixed-point
 187  * approximation a of 64/100 for which x/100 == (x * (u64)a) >> 32
 188  * holds for all x in [0, 10^8-1], namely a = 0x28f5c29. The actual
 189  * range happens to be somewhat larger (x <= 1073741898), but that's
 190  * irrelevant for our purpose.
 191  *
 192  * For dividing a number in the range [10^4, 10^6-1] by 100, we still
 193  * need a 32x32->64 bit multiply, so we simply use the same constant.
 194  *
 195  * For dividing a number in the range [100, 10^4-1] by 100, there are
 196  * several options. The simplest is (x * 0x147b) >> 19, which is valid
 197  * for all x <= 43698.
 198  */
 199
 200 static const u16 decpair[100] = {
 201 #define _(x) (__force u16) cpu_to_le16(((x % 10) | ((x / 10) << 8)) + 0x3030)
 202         _( 0), _( 1), _( 2), _( 3), _( 4), _( 5), _( 6), _( 7), _( 8), _( 9),
 203         _(10), _(11), _(12), _(13), _(14), _(15), _(16), _(17), _(18), _(19),
 204         _(20), _(21), _(22), _(23), _(24), _(25), _(26), _(27), _(28), _(29),
 205         _(30), _(31), _(32), _(33), _(34), _(35), _(36), _(37), _(38), _(39),
 206         _(40), _(41), _(42), _(43), _(44), _(45), _(46), _(47), _(48), _(49),
 207         _(50), _(51), _(52), _(53), _(54), _(55), _(56), _(57), _(58), _(59),
 208         _(60), _(61), _(62), _(63), _(64), _(65), _(66), _(67), _(68), _(69),
 209         _(70), _(71), _(72), _(73), _(74), _(75), _(76), _(77), _(78), _(79),
 210         _(80), _(81), _(82), _(83), _(84), _(85), _(86), _(87), _(88), _(89),
 211         _(90), _(91), _(92), _(93), _(94), _(95), _(96), _(97), _(98), _(99),
 212 #undef _
 213 };
 214
 215 /*
 216  * This will print a single '0' even if r == 0, since we would
 217  * immediately jump to out_r where two 0s would be written but only
 218  * one of them accounted for in buf. This is needed by ip4_string
 219  * below. All other callers pass a non-zero value of r.
 220 */
 221 static noinline_for_stack
 222 char *put_dec_trunc8(char *buf, unsigned r)
 223 {
 224         unsigned q;
 225
 226         /* 1 <= r < 10^8 */
 227         if (r < 100)
 228                 goto out_r;
 229
 230         /* 100 <= r < 10^8 */
 231         q = (r * (u64)0x28f5c29) >> 32;
 232         *((u16 *)buf) = decpair[r - 100*q];
 233         buf += 2;
 234
 235         /* 1 <= q < 10^6 */
 236         if (q < 100)
 237                 goto out_q;
 238
 239         /*  100 <= q < 10^6 */
 240         r = (q * (u64)0x28f5c29) >> 32;
 241         *((u16 *)buf) = decpair[q - 100*r];
 242         buf += 2;
 243
 244         /* 1 <= r < 10^4 */
 245         if (r < 100)
 246                 goto out_r;
 247
 248         /* 100 <= r < 10^4 */
 249         q = (r * 0x147b) >> 19;
 250         *((u16 *)buf) = decpair[r - 100*q];
 251         buf += 2;
 252 out_q:
 253         /* 1 <= q < 100 */
 254         r = q;
 255 out_r:
 256         /* 1 <= r < 100 */
 257         *((u16 *)buf) = decpair[r];
 258         buf += r < 10 ? 1 : 2;
 259         return buf;
 260 }
 261
 262 #if BITS_PER_LONG == 64 && BITS_PER_LONG_LONG == 64
 263 static noinline_for_stack
 264 char *put_dec_full8(char *buf, unsigned r)
 265 {
 266         unsigned q;
 267
 268         /* 0 <= r < 10^8 */
 269         q = (r * (u64)0x28f5c29) >> 32;
 270         *((u16 *)buf) = decpair[r - 100*q];
 271         buf += 2;
 272
 273         /* 0 <= q < 10^6 */
 274         r = (q * (u64)0x28f5c29) >> 32;
 275         *((u16 *)buf) = decpair[q - 100*r];
 276         buf += 2;
 277
 278         /* 0 <= r < 10^4 */
 279         q = (r * 0x147b) >> 19;
 280         *((u16 *)buf) = decpair[r - 100*q];
 281         buf += 2;
 282
 283         /* 0 <= q < 100 */
 284         *((u16 *)buf) = decpair[q];
 285         buf += 2;
 286         return buf;
 287 }
 288
 289 static noinline_for_stack
 290 char *put_dec(char *buf, unsigned long long n)
 291 {
 292         if (n >= 100*1000*1000)
 293                 buf = put_dec_full8(buf, do_div(n, 100*1000*1000));
 294         /* 1 <= n <= 1.6e11 */
 295         if (n >= 100*1000*1000)
 296                 buf = put_dec_full8(buf, do_div(n, 100*1000*1000));
 297         /* 1 <= n < 1e8 */
 298         return put_dec_trunc8(buf, n);
 299 }
 300
 301 #elif BITS_PER_LONG == 32 && BITS_PER_LONG_LONG == 64
 302
 303 static void
 304 put_dec_full4(char *buf, unsigned r)
 305 {
 306         unsigned q;
 307
 308         /* 0 <= r < 10^4 */
 309         q = (r * 0x147b) >> 19;
 310         *((u16 *)buf) = decpair[r - 100*q];
 311         buf += 2;
 312         /* 0 <= q < 100 */
 313         *((u16 *)buf) = decpair[q];
 314 }
 315
 316 /*
 317  * Call put_dec_full4 on x % 10000, return x / 10000.
 318  * The approximation x/10000 == (x * 0x346DC5D7) >> 43
 319  * holds for all x < 1,128,869,999.  The largest value this
 320  * helper will ever be asked to convert is 1,125,520,955.
 321  * (second call in the put_dec code, assuming n is all-ones).
 322  */
 323 static noinline_for_stack
 324 unsigned put_dec_helper4(char *buf, unsigned x)
 325 {
 326         uint32_t q = (x * (uint64_t)0x346DC5D7) >> 43;
 327
 328         put_dec_full4(buf, x - q * 10000);
 329         return q;
 330 }
 331
 332 /* Based on code by Douglas W. Jones found at
 333  * <http://www.cs.uiowa.edu/~jones/bcd/decimal.html#sixtyfour>
 334  * (with permission from the author).
 335  * Performs no 64-bit division and hence should be fast on 32-bit machines.
 336  */
 337 static
 338 char *put_dec(char *buf, unsigned long long n)
 339 {
 340         uint32_t d3, d2, d1, q, h;
 341
 342         if (n < 100*1000*1000)
 343                 return put_dec_trunc8(buf, n);
 344
 345         d1  = ((uint32_t)n >> 16); /* implicit "& 0xffff" */
 346         h   = (n >> 32);
 347         d2  = (h      ) & 0xffff;
 348         d3  = (h >> 16); /* implicit "& 0xffff" */
 349
 350         /* n = 2^48 d3 + 2^32 d2 + 2^16 d1 + d0
 351              = 281_4749_7671_0656 d3 + 42_9496_7296 d2 + 6_5536 d1 + d0 */
 352         q   = 656 * d3 + 7296 * d2 + 5536 * d1 + ((uint32_t)n & 0xffff);
 353         q = put_dec_helper4(buf, q);
 354
 355         q += 7671 * d3 + 9496 * d2 + 6 * d1;
 356         q = put_dec_helper4(buf+4, q);
 357
 358         q += 4749 * d3 + 42 * d2;
 359         q = put_dec_helper4(buf+8, q);
 360
 361         q += 281 * d3;
 362         buf += 12;
 363         if (q)
 364                 buf = put_dec_trunc8(buf, q);
 365         else while (buf[-1] == '0')
 366                 --buf;
 367
 368         return buf;
 369 }
 370
 371 #endif
 372
 373 /*
 374  * Convert passed number to decimal string.
 375  * Returns the length of string.  On buffer overflow, returns 0.
 376  *
 377  * If speed is not important, use snprintf(). It's easy to read the code.
 378  */
 379 int num_to_str(char *buf, int size, unsigned long long num, unsigned int width)
 380 {
 381         /* put_dec requires 2-byte alignment of the buffer. */
 382         char tmp[sizeof(num) * 3] __aligned(2);
 383         int idx, len;
 384
 385         /* put_dec() may work incorrectly for num = 0 (generate "", not "0") */
 386         if (num <= 9) {
 387                 tmp[0] = '0' + num;
 388                 len = 1;
 389         } else {
 390                 len = put_dec(tmp, num) - tmp;
 391         }
 392
 393         if (len > size || width > size)
 394                 return 0;
 395
 396         if (width > len) {
 397                 width = width - len;
 398                 for (idx = 0; idx < width; idx++)
 399                         buf[idx] = ' ';
 400         } else {
 401                 width = 0;
 402         }
 403
 404         for (idx = 0; idx < len; ++idx)
 405                 buf[idx + width] = tmp[len - idx - 1];
 406
 407         return len + width;
 408 }
 409
 410 #define SIGN    1               /* unsigned/signed, must be 1 */
 411 #define LEFT    2               /* left justified */
 412 #define PLUS    4               /* show plus */
 413 #define SPACE   8               /* space if plus */
 414 #define ZEROPAD 16              /* pad with zero, must be 16 == '0' - ' ' */
 415 #define SMALL   32              /* use lowercase in hex (must be 32 == 0x20) */
 416 #define SPECIAL 64              /* prefix hex with "0x", octal with "0" */
 417
 418 static_assert(SIGN == 1);
 419 static_assert(ZEROPAD == ('0' - ' '));
 420 static_assert(SMALL == ('a' ^ 'A'));
 421
 422 enum format_type {
 423         FORMAT_TYPE_NONE, /* Just a string part */
 424         FORMAT_TYPE_WIDTH,
 425         FORMAT_TYPE_PRECISION,
 426         FORMAT_TYPE_CHAR,
 427         FORMAT_TYPE_STR,
 428         FORMAT_TYPE_PTR,
 429         FORMAT_TYPE_PERCENT_CHAR,
 430         FORMAT_TYPE_INVALID,
 431         FORMAT_TYPE_LONG_LONG,
 432         FORMAT_TYPE_ULONG,
 433         FORMAT_TYPE_LONG,
 434         FORMAT_TYPE_UBYTE,
 435         FORMAT_TYPE_BYTE,
 436         FORMAT_TYPE_USHORT,
 437         FORMAT_TYPE_SHORT,
 438         FORMAT_TYPE_UINT,
 439         FORMAT_TYPE_INT,
 440         FORMAT_TYPE_SIZE_T,
 441         FORMAT_TYPE_PTRDIFF
 442 };
 443
 444 struct printf_spec {
 445         unsigned int    type:8;         /* format_type enum */
 446         signed int      field_width:24; /* width of output field */
 447         unsigned int    flags:8;        /* flags to number() */
 448         unsigned int    base:8;         /* number base, 8, 10 or 16 only */
 449         signed int      precision:16;   /* # of digits/chars */
 450 } __packed;
 451 static_assert(sizeof(struct printf_spec) == 8);
 452
 453 #define FIELD_WIDTH_MAX ((1 << 23) - 1)
 454 #define PRECISION_MAX ((1 << 15) - 1)
 455
 456 static noinline_for_stack
 457 char *number(char *buf, char *end, unsigned long long num,
 458              struct printf_spec spec)
 459 {
 460         /* put_dec requires 2-byte alignment of the buffer. */
 461         char tmp[3 * sizeof(num)] __aligned(2);
 462         char sign;
 463         char locase;
 464         int need_pfx = ((spec.flags & SPECIAL) && spec.base != 10);
 465         int i;
 466         bool is_zero = num == 0LL;
 467         int field_width = spec.field_width;
 468         int precision = spec.precision;
 469
 470         /* locase = 0 or 0x20. ORing digits or letters with 'locase'
 471          * produces same digits or (maybe lowercased) letters */
 472         locase = (spec.flags & SMALL);
 473         if (spec.flags & LEFT)
 474                 spec.flags &= ~ZEROPAD;
 475         sign = 0;
 476         if (spec.flags & SIGN) {
 477                 if ((signed long long)num < 0) {
 478                         sign = '-';
 479                         num = -(signed long long)num;
 480                         field_width--;
 481                 } else if (spec.flags & PLUS) {
 482                         sign = '+';
 483                         field_width--;
 484                 } else if (spec.flags & SPACE) {
 485                         sign = ' ';
 486                         field_width--;
 487                 }
 488         }
 489         if (need_pfx) {
 490                 if (spec.base == 16)
 491                         field_width -= 2;
 492                 else if (!is_zero)
 493                         field_width--;
 494         }
 495
 496         /* generate full string in tmp[], in reverse order */
 497         i = 0;
 498         if (num < spec.base)
 499                 tmp[i++] = hex_asc_upper[num] | locase;
 500         else if (spec.base != 10) { /* 8 or 16 */
 501                 int mask = spec.base - 1;
 502                 int shift = 3;
 503
 504                 if (spec.base == 16)
 505                         shift = 4;
 506                 do {
 507                         tmp[i++] = (hex_asc_upper[((unsigned char)num) & mask] | locase);
 508                         num >>= shift;
 509                 } while (num);
 510         } else { /* base 10 */
 511                 i = put_dec(tmp, num) - tmp;
 512         }
 513
 514         /* printing 100 using %2d gives "100", not "00" */
 515         if (i > precision)
 516                 precision = i;
 517         /* leading space padding */
 518         field_width -= precision;
 519         if (!(spec.flags & (ZEROPAD | LEFT))) {
 520                 while (--field_width >= 0) {
 521                         if (buf < end)
 522                                 *buf = ' ';
 523                         ++buf;
 524                 }
 525         }
 526         /* sign */
 527         if (sign) {
 528                 if (buf < end)
 529                         *buf = sign;
 530                 ++buf;
 531         }
 532         /* "0x" / "0" prefix */
 533         if (need_pfx) {
 534                 if (spec.base == 16 || !is_zero) {
 535                         if (buf < end)
 536                                 *buf = '0';
 537                         ++buf;
 538                 }
 539                 if (spec.base == 16) {
 540                         if (buf < end)
 541                                 *buf = ('X' | locase);
 542                         ++buf;
 543                 }
 544         }
 545         /* zero or space padding */
 546         if (!(spec.flags & LEFT)) {
 547                 char c = ' ' + (spec.flags & ZEROPAD);
 548
 549                 while (--field_width >= 0) {
 550                         if (buf < end)
 551                                 *buf = c;
 552                         ++buf;
 553                 }
 554         }
 555         /* hmm even more zero padding? */
 556         while (i <= --precision) {
 557                 if (buf < end)
 558                         *buf = '0';
 559                 ++buf;
 560         }
 561         /* actual digits of result */
 562         while (--i >= 0) {
 563                 if (buf < end)
 564                         *buf = tmp[i];
 565                 ++buf;
 566         }
 567         /* trailing space padding */
 568         while (--field_width >= 0) {
 569                 if (buf < end)
 570                         *buf = ' ';
 571                 ++buf;
 572         }
 573
 574         return buf;
 575 }
 576
 577 static noinline_for_stack
 578 char *special_hex_number(char *buf, char *end, unsigned long long num, int size)
 579 {
 580         struct printf_spec spec;
 581
 582         spec.type = FORMAT_TYPE_PTR;
 583         spec.field_width = 2 + 2 * size;        /* 0x + hex */
 584         spec.flags = SPECIAL | SMALL | ZEROPAD;
 585         spec.base = 16;
 586         spec.precision = -1;
 587
 588         return number(buf, end, num, spec);
 589 }
 590
 591 static void move_right(char *buf, char *end, unsigned len, unsigned spaces)
 592 {
 593         size_t size;
 594         if (buf >= end) /* nowhere to put anything */
 595                 return;
 596         size = end - buf;
 597         if (size <= spaces) {
 598                 memset(buf, ' ', size);
 599                 return;
 600         }
 601         if (len) {
 602                 if (len > size - spaces)
 603                         len = size - spaces;
 604                 memmove(buf + spaces, buf, len);
 605         }
 606         memset(buf, ' ', spaces);
 607 }
 608
 609 /*
 610  * Handle field width padding for a string.
 611  * @buf: current buffer position
 612  * @n: length of string
 613  * @end: end of output buffer
 614  * @spec: for field width and flags
 615  * Returns: new buffer position after padding.
 616  */
 617 static noinline_for_stack
 618 char *widen_string(char *buf, int n, char *end, struct printf_spec spec)
 619 {
 620         unsigned spaces;
 621
 622         if (likely(n >= spec.field_width))
 623                 return buf;
 624         /* we want to pad the sucker */
 625         spaces = spec.field_width - n;
 626         if (!(spec.flags & LEFT)) {
 627                 move_right(buf - n, end, n, spaces);
 628                 return buf + spaces;
 629         }
 630         while (spaces--) {
 631                 if (buf < end)
 632                         *buf = ' ';
 633                 ++buf;
 634         }
 635         return buf;
 636 }
 637
 638 /* Handle string from a well known address. */
 639 static char *string_nocheck(char *buf, char *end, const char *s,
 640                             struct printf_spec spec)
 641 {
 642         int len = 0;
 643         int lim = spec.precision;
 644
 645         while (lim--) {
 646                 char c = *s++;
 647                 if (!c)
 648                         break;
 649                 if (buf < end)
 650                         *buf = c;
 651                 ++buf;
 652                 ++len;
 653         }
 654         return widen_string(buf, len, end, spec);
 655 }
 656
 657 static char *err_ptr(char *buf, char *end, void *ptr,
 658                      struct printf_spec spec)
 659 {
 660         int err = PTR_ERR(ptr);
 661         const char *sym = errname(err);
 662
 663         if (sym)
 664                 return string_nocheck(buf, end, sym, spec);
 665
 666         /*
 667          * Somebody passed ERR_PTR(-1234) or some other non-existing
 668          * Efoo - or perhaps CONFIG_SYMBOLIC_ERRNAME=n. Fall back to
 669          * printing it as its decimal representation.
 670          */
 671         spec.flags |= SIGN;
 672         spec.base = 10;
 673         return number(buf, end, err, spec);
 674 }
 675
 676 /* Be careful: error messages must fit into the given buffer. */
 677 static char *error_string(char *buf, char *end, const char *s,
 678                           struct printf_spec spec)
 679 {
 680         /*
 681          * Hard limit to avoid a completely insane messages. It actually
 682          * works pretty well because most error messages are in
 683          * the many pointer format modifiers.
 684          */
 685         if (spec.precision == -1)
 686                 spec.precision = 2 * sizeof(void *);
 687
 688         return string_nocheck(buf, end, s, spec);
 689 }
 690
 691 /*
 692  * Do not call any complex external code here. Nested printk()/vsprintf()
 693  * might cause infinite loops. Failures might break printk() and would
 694  * be hard to debug.
 695  */
 696 static const char *check_pointer_msg(const void *ptr)
 697 {
 698         if (!ptr)
 699                 return "(null)";
 700
 701         if ((unsigned long)ptr < PAGE_SIZE || IS_ERR_VALUE(ptr))
 702                 return "(efault)";
 703
 704         return NULL;
 705 }
 706
 707 static int check_pointer(char **buf, char *end, const void *ptr,
 708                          struct printf_spec spec)
 709 {
 710         const char *err_msg;
 711
 712         err_msg = check_pointer_msg(ptr);
 713         if (err_msg) {
 714                 *buf = error_string(*buf, end, err_msg, spec);
 715                 return -EFAULT;
 716         }
 717
 718         return 0;
 719 }
 720
 721 static noinline_for_stack
 722 char *string(char *buf, char *end, const char *s,
 723              struct printf_spec spec)
 724 {
 725         if (check_pointer(&buf, end, s, spec))
 726                 return buf;
 727
 728         return string_nocheck(buf, end, s, spec);
 729 }
 730
 731 static char *pointer_string(char *buf, char *end,
 732                             const void *ptr,
 733                             struct printf_spec spec)
 734 {
 735         spec.base = 16;
 736         spec.flags |= SMALL;
 737         if (spec.field_width == -1) {
 738                 spec.field_width = 2 * sizeof(ptr);
 739                 spec.flags |= ZEROPAD;
 740         }
 741
 742         return number(buf, end, (unsigned long int)ptr, spec);
 743 }
 744
 745 /* Make pointers available for printing early in the boot sequence. */
 746 static int debug_boot_weak_hash __ro_after_init;
 747
 748 static int __init debug_boot_weak_hash_enable(char *str)
 749 {
 750         debug_boot_weak_hash = 1;
 751         pr_info("debug_boot_weak_hash enabled\n");
 752         return 0;
 753 }
 754 early_param("debug_boot_weak_hash", debug_boot_weak_hash_enable);
 755
 756 static bool filled_random_ptr_key __read_mostly;
 757 static siphash_key_t ptr_key __read_mostly;
 758
 759 static int fill_ptr_key(struct notifier_block *nb, unsigned long action, void *data)
 760 {
 761         get_random_bytes(&ptr_key, sizeof(ptr_key));
 762
 763         /* Pairs with smp_rmb() before reading ptr_key. */
 764         smp_wmb();
 765         WRITE_ONCE(filled_random_ptr_key, true);
 766         return NOTIFY_DONE;
 767 }
 768
 769 static int __init vsprintf_init_hashval(void)
 770 {
 771         static struct notifier_block fill_ptr_key_nb = { .notifier_call = fill_ptr_key };
 772         execute_with_initialized_rng(&fill_ptr_key_nb);
 773         return 0;
 774 }
 775 subsys_initcall(vsprintf_init_hashval)
 776
 777 /* Maps a pointer to a 32 bit unique identifier. */
 778 static inline int __ptr_to_hashval(const void *ptr, unsigned long *hashval_out)
 779 {
 780         unsigned long hashval;
 781
 782         if (!READ_ONCE(filled_random_ptr_key))
 783                 return -EBUSY;
 784
 785         /* Pairs with smp_wmb() after writing ptr_key. */
 786         smp_rmb();
 787
 788 #ifdef CONFIG_64BIT
 789         hashval = (unsigned long)siphash_1u64((u64)ptr, &ptr_key);
 790         /*
 791          * Mask off the first 32 bits, this makes explicit that we have
 792          * modified the address (and 32 bits is plenty for a unique ID).
 793          */
 794         hashval = hashval & 0xffffffff;
 795 #else
 796         hashval = (unsigned long)siphash_1u32((u32)ptr, &ptr_key);
 797 #endif
 798         *hashval_out = hashval;
 799         return 0;
 800 }
 801
 802 int ptr_to_hashval(const void *ptr, unsigned long *hashval_out)
 803 {
 804         return __ptr_to_hashval(ptr, hashval_out);
 805 }
 806
 807 static char *ptr_to_id(char *buf, char *end, const void *ptr,
 808                        struct printf_spec spec)
 809 {
 810         const char *str = sizeof(ptr) == 8 ? "(____ptrval____)" : "(ptrval)";
 811         unsigned long hashval;
 812         int ret;
 813
 814         /*
 815          * Print the real pointer value for NULL and error pointers,
 816          * as they are not actual addresses.
 817          */
 818         if (IS_ERR_OR_NULL(ptr))
 819                 return pointer_string(buf, end, ptr, spec);
 820
 821         /* When debugging early boot use non-cryptographically secure hash. */
 822         if (unlikely(debug_boot_weak_hash)) {
 823                 hashval = hash_long((unsigned long)ptr, 32);
 824                 return pointer_string(buf, end, (const void *)hashval, spec);
 825         }
 826
 827         ret = __ptr_to_hashval(ptr, &hashval);
 828         if (ret) {
 829                 spec.field_width = 2 * sizeof(ptr);
 830                 /* string length must be less than default_width */
 831                 return error_string(buf, end, str, spec);
 832         }
 833
 834         return pointer_string(buf, end, (const void *)hashval, spec);
 835 }
 836
 837 static char *default_pointer(char *buf, char *end, const void *ptr,
 838                              struct printf_spec spec)
 839 {
 840         /*
 841          * default is to _not_ leak addresses, so hash before printing,
 842          * unless no_hash_pointers is specified on the command line.
 843          */
 844         if (unlikely(no_hash_pointers))
 845                 return pointer_string(buf, end, ptr, spec);
 846
 847         return ptr_to_id(buf, end, ptr, spec);
 848 }
 849
 850 int kptr_restrict __read_mostly;
 851
 852 static noinline_for_stack
 853 char *restricted_pointer(char *buf, char *end, const void *ptr,
 854                          struct printf_spec spec)
 855 {
 856         switch (kptr_restrict) {
 857         case 0:
 858                 /* Handle as %p, hash and do _not_ leak addresses. */
 859                 return default_pointer(buf, end, ptr, spec);
 860         case 1: {
 861                 const struct cred *cred;
 862
 863                 /*
 864                  * kptr_restrict==1 cannot be used in IRQ context
 865                  * because its test for CAP_SYSLOG would be meaningless.
 866                  */
 867                 if (in_hardirq() || in_serving_softirq() || in_nmi()) {
 868                         if (spec.field_width == -1)
 869                                 spec.field_width = 2 * sizeof(ptr);
 870                         return error_string(buf, end, "pK-error", spec);
 871                 }
 872
 873                 /*
 874                  * Only print the real pointer value if the current
 875                  * process has CAP_SYSLOG and is running with the
 876                  * same credentials it started with. This is because
 877                  * access to files is checked at open() time, but %pK
 878                  * checks permission at read() time. We don't want to
 879                  * leak pointer values if a binary opens a file using
 880                  * %pK and then elevates privileges before reading it.
 881                  */
 882                 cred = current_cred();
 883                 if (!has_capability_noaudit(current, CAP_SYSLOG) ||
 884                     !uid_eq(cred->euid, cred->uid) ||
 885                     !gid_eq(cred->egid, cred->gid))
 886                         ptr = NULL;
 887                 break;
 888         }
 889         case 2:
 890         default:
 891                 /* Always print 0's for %pK */
 892                 ptr = NULL;
 893                 break;
 894         }
 895
 896         return pointer_string(buf, end, ptr, spec);
 897 }
 898
 899 static noinline_for_stack
 900 char *dentry_name(char *buf, char *end, const struct dentry *d, struct printf_spec spec,
 901                   const char *fmt)
 902 {
 903         const char *array[4], *s;
 904         const struct dentry *p;
 905         int depth;
 906         int i, n;
 907
 908         switch (fmt[1]) {
 909                 case '2': case '3': case '4':
 910                         depth = fmt[1] - '0';
 911                         break;
 912                 default:
 913                         depth = 1;
 914         }
 915
 916         rcu_read_lock();
 917         for (i = 0; i < depth; i++, d = p) {
 918                 if (check_pointer(&buf, end, d, spec)) {
 919                         rcu_read_unlock();
 920                         return buf;
 921                 }
 922
 923                 p = READ_ONCE(d->d_parent);
 924                 array[i] = READ_ONCE(d->d_name.name);
 925                 if (p == d) {
 926                         if (i)
 927                                 array[i] = "";
 928                         i++;
 929                         break;
 930                 }
 931         }
 932         s = array[--i];
 933         for (n = 0; n != spec.precision; n++, buf++) {
 934                 char c = *s++;
 935                 if (!c) {
 936                         if (!i)
 937                                 break;
 938                         c = '/';
 939                         s = array[--i];
 940                 }
 941                 if (buf < end)
 942                         *buf = c;
 943         }
 944         rcu_read_unlock();
 945         return widen_string(buf, n, end, spec);
 946 }
 947
 948 static noinline_for_stack
 949 char *file_dentry_name(char *buf, char *end, const struct file *f,
 950                         struct printf_spec spec, const char *fmt)
 951 {
 952         if (check_pointer(&buf, end, f, spec))
 953                 return buf;
 954
 955         return dentry_name(buf, end, f->f_path.dentry, spec, fmt);
 956 }
 957 #ifdef CONFIG_BLOCK
 958 static noinline_for_stack
 959 char *bdev_name(char *buf, char *end, struct block_device *bdev,
 960                 struct printf_spec spec, const char *fmt)
 961 {
 962         struct gendisk *hd;
 963
 964         if (check_pointer(&buf, end, bdev, spec))
 965                 return buf;
 966
 967         hd = bdev->bd_disk;
 968         buf = string(buf, end, hd->disk_name, spec);
 969         if (bdev_is_partition(bdev)) {
 970                 if (isdigit(hd->disk_name[strlen(hd->disk_name)-1])) {
 971                         if (buf < end)
 972                                 *buf = 'p';
 973                         buf++;
 974                 }
 975                 buf = number(buf, end, bdev_partno(bdev), spec);
 976         }
 977         return buf;
 978 }
 979 #endif
 980
 981 static noinline_for_stack
 982 char *symbol_string(char *buf, char *end, void *ptr,
 983                     struct printf_spec spec, const char *fmt)
 984 {
 985         unsigned long value;
 986 #ifdef CONFIG_KALLSYMS
 987         char sym[KSYM_SYMBOL_LEN];
 988 #endif
 989
 990         if (fmt[1] == 'R')
 991                 ptr = __builtin_extract_return_addr(ptr);
 992         value = (unsigned long)ptr;
 993
 994 #ifdef CONFIG_KALLSYMS
 995         if (*fmt == 'B' && fmt[1] == 'b')
 996                 sprint_backtrace_build_id(sym, value);
 997         else if (*fmt == 'B')
 998                 sprint_backtrace(sym, value);
 999         else if (*fmt == 'S' && (fmt[1] == 'b' || (fmt[1] == 'R' && fmt[2] == 'b')))
1000                 sprint_symbol_build_id(sym, value);
1001         else if (*fmt != 's')
1002                 sprint_symbol(sym, value);
1003         else
1004                 sprint_symbol_no_offset(sym, value);
1005
1006         return string_nocheck(buf, end, sym, spec);
1007 #else
1008         return special_hex_number(buf, end, value, sizeof(void *));
1009 #endif
1010 }
1011
1012 static const struct printf_spec default_str_spec = {
1013         .field_width = -1,
1014         .precision = -1,
1015 };
1016
1017 static const struct printf_spec default_flag_spec = {
1018         .base = 16,
1019         .precision = -1,
1020         .flags = SPECIAL | SMALL,
1021 };
1022
1023 static const struct printf_spec default_dec_spec = {
1024         .base = 10,
1025         .precision = -1,
1026 };
1027
1028 static const struct printf_spec default_dec02_spec = {
1029         .base = 10,
1030         .field_width = 2,
1031         .precision = -1,
1032         .flags = ZEROPAD,
1033 };
1034
1035 static const struct printf_spec default_dec04_spec = {
1036         .base = 10,
1037         .field_width = 4,
1038         .precision = -1,
1039         .flags = ZEROPAD,
1040 };
1041
1042 static noinline_for_stack
1043 char *resource_string(char *buf, char *end, struct resource *res,
1044                       struct printf_spec spec, const char *fmt)
1045 {
1046 #ifndef IO_RSRC_PRINTK_SIZE
1047 #define IO_RSRC_PRINTK_SIZE     6
1048 #endif
1049
1050 #ifndef MEM_RSRC_PRINTK_SIZE
1051 #define MEM_RSRC_PRINTK_SIZE    10
1052 #endif
1053         static const struct printf_spec io_spec = {
1054                 .base = 16,
1055                 .field_width = IO_RSRC_PRINTK_SIZE,
1056                 .precision = -1,
1057                 .flags = SPECIAL | SMALL | ZEROPAD,
1058         };
1059         static const struct printf_spec mem_spec = {
1060                 .base = 16,
1061                 .field_width = MEM_RSRC_PRINTK_SIZE,
1062                 .precision = -1,
1063                 .flags = SPECIAL | SMALL | ZEROPAD,
1064         };
1065         static const struct printf_spec bus_spec = {
1066                 .base = 16,
1067                 .field_width = 2,
1068                 .precision = -1,
1069                 .flags = SMALL | ZEROPAD,
1070         };
1071         static const struct printf_spec str_spec = {
1072                 .field_width = -1,
1073                 .precision = 10,
1074                 .flags = LEFT,
1075         };
1076
1077         /* 32-bit res (sizeof==4): 10 chars in dec, 10 in hex ("0x" + 8)
1078          * 64-bit res (sizeof==8): 20 chars in dec, 18 in hex ("0x" + 16) */
1079 #define RSRC_BUF_SIZE           ((2 * sizeof(resource_size_t)) + 4)
1080 #define FLAG_BUF_SIZE           (2 * sizeof(res->flags))
1081 #define DECODED_BUF_SIZE        sizeof("[mem - 64bit pref window disabled]")
1082 #define RAW_BUF_SIZE            sizeof("[mem - flags 0x]")
1083         char sym[MAX(2*RSRC_BUF_SIZE + DECODED_BUF_SIZE,
1084                      2*RSRC_BUF_SIZE + FLAG_BUF_SIZE + RAW_BUF_SIZE)];
1085
1086         char *p = sym, *pend = sym + sizeof(sym);
1087         int decode = (fmt[0] == 'R') ? 1 : 0;
1088         const struct printf_spec *specp;
1089
1090         if (check_pointer(&buf, end, res, spec))
1091                 return buf;
1092
1093         *p++ = '[';
1094         if (res->flags & IORESOURCE_IO) {
1095                 p = string_nocheck(p, pend, "io  ", str_spec);
1096                 specp = &io_spec;
1097         } else if (res->flags & IORESOURCE_MEM) {
1098                 p = string_nocheck(p, pend, "mem ", str_spec);
1099                 specp = &mem_spec;
1100         } else if (res->flags & IORESOURCE_IRQ) {
1101                 p = string_nocheck(p, pend, "irq ", str_spec);
1102                 specp = &default_dec_spec;
1103         } else if (res->flags & IORESOURCE_DMA) {
1104                 p = string_nocheck(p, pend, "dma ", str_spec);
1105                 specp = &default_dec_spec;
1106         } else if (res->flags & IORESOURCE_BUS) {
1107                 p = string_nocheck(p, pend, "bus ", str_spec);
1108                 specp = &bus_spec;
1109         } else {
1110                 p = string_nocheck(p, pend, "??? ", str_spec);
1111                 specp = &mem_spec;
1112                 decode = 0;
1113         }
1114         if (decode && res->flags & IORESOURCE_UNSET) {
1115                 p = string_nocheck(p, pend, "size ", str_spec);
1116                 p = number(p, pend, resource_size(res), *specp);
1117         } else {
1118                 p = number(p, pend, res->start, *specp);
1119                 if (res->start != res->end) {
1120                         *p++ = '-';
1121                         p = number(p, pend, res->end, *specp);
1122                 }
1123         }
1124         if (decode) {
1125                 if (res->flags & IORESOURCE_MEM_64)
1126                         p = string_nocheck(p, pend, " 64bit", str_spec);
1127                 if (res->flags & IORESOURCE_PREFETCH)
1128                         p = string_nocheck(p, pend, " pref", str_spec);
1129                 if (res->flags & IORESOURCE_WINDOW)
1130                         p = string_nocheck(p, pend, " window", str_spec);
1131                 if (res->flags & IORESOURCE_DISABLED)
1132                         p = string_nocheck(p, pend, " disabled", str_spec);
1133         } else {
1134                 p = string_nocheck(p, pend, " flags ", str_spec);
1135                 p = number(p, pend, res->flags, default_flag_spec);
1136         }
1137         *p++ = ']';
1138         *p = '\0';
1139
1140         return string_nocheck(buf, end, sym, spec);
1141 }
1142
1143 static noinline_for_stack
1144 char *hex_string(char *buf, char *end, u8 *addr, struct printf_spec spec,
1145                  const char *fmt)
1146 {
1147         int i, len = 1;         /* if we pass '%ph[CDN]', field width remains
1148                                    negative value, fallback to the default */
1149         char separator;
1150
1151         if (spec.field_width == 0)
1152                 /* nothing to print */
1153                 return buf;
1154
1155         if (check_pointer(&buf, end, addr, spec))
1156                 return buf;
1157
1158         switch (fmt[1]) {
1159         case 'C':
1160                 separator = ':';
1161                 break;
1162         case 'D':
1163                 separator = '-';
1164                 break;
1165         case 'N':
1166                 separator = 0;
1167                 break;
1168         default:
1169                 separator = ' ';
1170                 break;
1171         }
1172
1173         if (spec.field_width > 0)
1174                 len = min_t(int, spec.field_width, 64);
1175
1176         for (i = 0; i < len; ++i) {
1177                 if (buf < end)
1178                         *buf = hex_asc_hi(addr[i]);
1179                 ++buf;
1180                 if (buf < end)
1181                         *buf = hex_asc_lo(addr[i]);
1182                 ++buf;
1183
1184                 if (separator && i != len - 1) {
1185                         if (buf < end)
1186                                 *buf = separator;
1187                         ++buf;
1188                 }
1189         }
1190
1191         return buf;
1192 }
1193
1194 static noinline_for_stack
1195 char *bitmap_string(char *buf, char *end, const unsigned long *bitmap,
1196                     struct printf_spec spec, const char *fmt)
1197 {
1198         const int CHUNKSZ = 32;
1199         int nr_bits = max_t(int, spec.field_width, 0);
1200         int i, chunksz;
1201         bool first = true;
1202
1203         if (check_pointer(&buf, end, bitmap, spec))
1204                 return buf;
1205
1206         /* reused to print numbers */
1207         spec = (struct printf_spec){ .flags = SMALL | ZEROPAD, .base = 16 };
1208
1209         chunksz = nr_bits & (CHUNKSZ - 1);
1210         if (chunksz == 0)
1211                 chunksz = CHUNKSZ;
1212
1213         i = ALIGN(nr_bits, CHUNKSZ) - CHUNKSZ;
1214         for (; i >= 0; i -= CHUNKSZ) {
1215                 u32 chunkmask, val;
1216                 int word, bit;
1217
1218                 chunkmask = ((1ULL << chunksz) - 1);
1219                 word = i / BITS_PER_LONG;
1220                 bit = i % BITS_PER_LONG;
1221                 val = (bitmap[word] >> bit) & chunkmask;
1222
1223                 if (!first) {
1224                         if (buf < end)
1225                                 *buf = ',';
1226                         buf++;
1227                 }
1228                 first = false;
1229
1230                 spec.field_width = DIV_ROUND_UP(chunksz, 4);
1231                 buf = number(buf, end, val, spec);
1232
1233                 chunksz = CHUNKSZ;
1234         }
1235         return buf;
1236 }
1237
1238 static noinline_for_stack
1239 char *bitmap_list_string(char *buf, char *end, const unsigned long *bitmap,
1240                          struct printf_spec spec, const char *fmt)
1241 {
1242         int nr_bits = max_t(int, spec.field_width, 0);
1243         bool first = true;
1244         int rbot, rtop;
1245
1246         if (check_pointer(&buf, end, bitmap, spec))
1247                 return buf;
1248
1249         for_each_set_bitrange(rbot, rtop, bitmap, nr_bits) {
1250                 if (!first) {
1251                         if (buf < end)
1252                                 *buf = ',';
1253                         buf++;
1254                 }
1255                 first = false;
1256
1257                 buf = number(buf, end, rbot, default_dec_spec);
1258                 if (rtop == rbot + 1)
1259                         continue;
1260
1261                 if (buf < end)
1262                         *buf = '-';
1263                 buf = number(++buf, end, rtop - 1, default_dec_spec);
1264         }
1265         return buf;
1266 }
1267
1268 static noinline_for_stack
1269 char *mac_address_string(char *buf, char *end, u8 *addr,
1270                          struct printf_spec spec, const char *fmt)
1271 {
1272         char mac_addr[sizeof("xx:xx:xx:xx:xx:xx")];
1273         char *p = mac_addr;
1274         int i;
1275         char separator;
1276         bool reversed = false;
1277
1278         if (check_pointer(&buf, end, addr, spec))
1279                 return buf;
1280
1281         switch (fmt[1]) {
1282         case 'F':
1283                 separator = '-';
1284                 break;
1285
1286         case 'R':
1287                 reversed = true;
1288                 fallthrough;
1289
1290         default:
1291                 separator = ':';
1292                 break;
1293         }
1294
1295         for (i = 0; i < 6; i++) {
1296                 if (reversed)
1297                         p = hex_byte_pack(p, addr[5 - i]);
1298                 else
1299                         p = hex_byte_pack(p, addr[i]);
1300
1301                 if (fmt[0] == 'M' && i != 5)
1302                         *p++ = separator;
1303         }
1304         *p = '\0';
1305
1306         return string_nocheck(buf, end, mac_addr, spec);
1307 }
1308
1309 static noinline_for_stack
1310 char *ip4_string(char *p, const u8 *addr, const char *fmt)
1311 {
1312         int i;
1313         bool leading_zeros = (fmt[0] == 'i');
1314         int index;
1315         int step;
1316
1317         switch (fmt[2]) {
1318         case 'h':
1319 #ifdef __BIG_ENDIAN
1320                 index = 0;
1321                 step = 1;
1322 #else
1323                 index = 3;
1324                 step = -1;
1325 #endif
1326                 break;
1327         case 'l':
1328                 index = 3;
1329                 step = -1;
1330                 break;
1331         case 'n':
1332         case 'b':
1333         default:
1334                 index = 0;
1335                 step = 1;
1336                 break;
1337         }
1338         for (i = 0; i < 4; i++) {
1339                 char temp[4] __aligned(2);      /* hold each IP quad in reverse order */
1340                 int digits = put_dec_trunc8(temp, addr[index]) - temp;
1341                 if (leading_zeros) {
1342                         if (digits < 3)
1343                                 *p++ = '0';
1344                         if (digits < 2)
1345                                 *p++ = '0';
1346                 }
1347                 /* reverse the digits in the quad */
1348                 while (digits--)
1349                         *p++ = temp[digits];
1350                 if (i < 3)
1351                         *p++ = '.';
1352                 index += step;
1353         }
1354         *p = '\0';
1355
1356         return p;
1357 }
1358
1359 static noinline_for_stack
1360 char *ip6_compressed_string(char *p, const char *addr)
1361 {
1362         int i, j, range;
1363         unsigned char zerolength[8];
1364         int longest = 1;
1365         int colonpos = -1;
1366         u16 word;
1367         u8 hi, lo;
1368         bool needcolon = false;
1369         bool useIPv4;
1370         struct in6_addr in6;
1371
1372         memcpy(&in6, addr, sizeof(struct in6_addr));
1373
1374         useIPv4 = ipv6_addr_v4mapped(&in6) || ipv6_addr_is_isatap(&in6);
1375
1376         memset(zerolength, 0, sizeof(zerolength));
1377
1378         if (useIPv4)
1379                 range = 6;
1380         else
1381                 range = 8;
1382
1383         /* find position of longest 0 run */
1384         for (i = 0; i < range; i++) {
1385                 for (j = i; j < range; j++) {
1386                         if (in6.s6_addr16[j] != 0)
1387                                 break;
1388                         zerolength[i]++;
1389                 }
1390         }
1391         for (i = 0; i < range; i++) {
1392                 if (zerolength[i] > longest) {
1393                         longest = zerolength[i];
1394                         colonpos = i;
1395                 }
1396         }
1397         if (longest == 1)               /* don't compress a single 0 */
1398                 colonpos = -1;
1399
1400         /* emit address */
1401         for (i = 0; i < range; i++) {
1402                 if (i == colonpos) {
1403                         if (needcolon || i == 0)
1404                                 *p++ = ':';
1405                         *p++ = ':';
1406                         needcolon = false;
1407                         i += longest - 1;
1408                         continue;
1409                 }
1410                 if (needcolon) {
1411                         *p++ = ':';
1412                         needcolon = false;
1413                 }
1414                 /* hex u16 without leading 0s */
1415                 word = ntohs(in6.s6_addr16[i]);
1416                 hi = word >> 8;
1417                 lo = word & 0xff;
1418                 if (hi) {
1419                         if (hi > 0x0f)
1420                                 p = hex_byte_pack(p, hi);
1421                         else
1422                                 *p++ = hex_asc_lo(hi);
1423                         p = hex_byte_pack(p, lo);
1424                 }
1425                 else if (lo > 0x0f)
1426                         p = hex_byte_pack(p, lo);
1427                 else
1428                         *p++ = hex_asc_lo(lo);
1429                 needcolon = true;
1430         }
1431
1432         if (useIPv4) {
1433                 if (needcolon)
1434                         *p++ = ':';
1435                 p = ip4_string(p, &in6.s6_addr[12], "I4");
1436         }
1437         *p = '\0';
1438
1439         return p;
1440 }
1441
1442 static noinline_for_stack
1443 char *ip6_string(char *p, const char *addr, const char *fmt)
1444 {
1445         int i;
1446
1447         for (i = 0; i < 8; i++) {
1448                 p = hex_byte_pack(p, *addr++);
1449                 p = hex_byte_pack(p, *addr++);
1450                 if (fmt[0] == 'I' && i != 7)
1451                         *p++ = ':';
1452         }
1453         *p = '\0';
1454
1455         return p;
1456 }
1457
1458 static noinline_for_stack
1459 char *ip6_addr_string(char *buf, char *end, const u8 *addr,
1460                       struct printf_spec spec, const char *fmt)
1461 {
1462         char ip6_addr[sizeof("xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:255.255.255.255")];
1463
1464         if (fmt[0] == 'I' && fmt[2] == 'c')
1465                 ip6_compressed_string(ip6_addr, addr);
1466         else
1467                 ip6_string(ip6_addr, addr, fmt);
1468
1469         return string_nocheck(buf, end, ip6_addr, spec);
1470 }
1471
1472 static noinline_for_stack
1473 char *ip4_addr_string(char *buf, char *end, const u8 *addr,
1474                       struct printf_spec spec, const char *fmt)
1475 {
1476         char ip4_addr[sizeof("255.255.255.255")];
1477
1478         ip4_string(ip4_addr, addr, fmt);
1479
1480         return string_nocheck(buf, end, ip4_addr, spec);
1481 }
1482
1483 static noinline_for_stack
1484 char *ip6_addr_string_sa(char *buf, char *end, const struct sockaddr_in6 *sa,
1485                          struct printf_spec spec, const char *fmt)
1486 {
1487         bool have_p = false, have_s = false, have_f = false, have_c = false;
1488         char ip6_addr[sizeof("[xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:255.255.255.255]") +
1489                       sizeof(":12345") + sizeof("/123456789") +
1490                       sizeof("%1234567890")];
1491         char *p = ip6_addr, *pend = ip6_addr + sizeof(ip6_addr);
1492         const u8 *addr = (const u8 *) &sa->sin6_addr;
1493         char fmt6[2] = { fmt[0], '6' };
1494         u8 off = 0;
1495
1496         fmt++;
1497         while (isalpha(*++fmt)) {
1498                 switch (*fmt) {
1499                 case 'p':
1500                         have_p = true;
1501                         break;
1502                 case 'f':
1503                         have_f = true;
1504                         break;
1505                 case 's':
1506                         have_s = true;
1507                         break;
1508                 case 'c':
1509                         have_c = true;
1510                         break;
1511                 }
1512         }
1513
1514         if (have_p || have_s || have_f) {
1515                 *p = '[';
1516                 off = 1;
1517         }
1518
1519         if (fmt6[0] == 'I' && have_c)
1520                 p = ip6_compressed_string(ip6_addr + off, addr);
1521         else
1522                 p = ip6_string(ip6_addr + off, addr, fmt6);
1523
1524         if (have_p || have_s || have_f)
1525                 *p++ = ']';
1526
1527         if (have_p) {
1528                 *p++ = ':';
1529                 p = number(p, pend, ntohs(sa->sin6_port), spec);
1530         }
1531         if (have_f) {
1532                 *p++ = '/';
1533                 p = number(p, pend, ntohl(sa->sin6_flowinfo &
1534                                           IPV6_FLOWINFO_MASK), spec);
1535         }
1536         if (have_s) {
1537                 *p++ = '%';
1538                 p = number(p, pend, sa->sin6_scope_id, spec);
1539         }
1540         *p = '\0';
1541
1542         return string_nocheck(buf, end, ip6_addr, spec);
1543 }
1544
1545 static noinline_for_stack
1546 char *ip4_addr_string_sa(char *buf, char *end, const struct sockaddr_in *sa,
1547                          struct printf_spec spec, const char *fmt)
1548 {
1549         bool have_p = false;
1550         char *p, ip4_addr[sizeof("255.255.255.255") + sizeof(":12345")];
1551         char *pend = ip4_addr + sizeof(ip4_addr);
1552         const u8 *addr = (const u8 *) &sa->sin_addr.s_addr;
1553         char fmt4[3] = { fmt[0], '4', 0 };
1554
1555         fmt++;
1556         while (isalpha(*++fmt)) {
1557                 switch (*fmt) {
1558                 case 'p':
1559                         have_p = true;
1560                         break;
1561                 case 'h':
1562                 case 'l':
1563                 case 'n':
1564                 case 'b':
1565                         fmt4[2] = *fmt;
1566                         break;
1567                 }
1568         }
1569
1570         p = ip4_string(ip4_addr, addr, fmt4);
1571         if (have_p) {
1572                 *p++ = ':';
1573                 p = number(p, pend, ntohs(sa->sin_port), spec);
1574         }
1575         *p = '\0';
1576
1577         return string_nocheck(buf, end, ip4_addr, spec);
1578 }
1579
1580 static noinline_for_stack
1581 char *ip_addr_string(char *buf, char *end, const void *ptr,
1582                      struct printf_spec spec, const char *fmt)
1583 {
1584         char *err_fmt_msg;
1585
1586         if (check_pointer(&buf, end, ptr, spec))
1587                 return buf;
1588
1589         switch (fmt[1]) {
1590         case '6':
1591                 return ip6_addr_string(buf, end, ptr, spec, fmt);
1592         case '4':
1593                 return ip4_addr_string(buf, end, ptr, spec, fmt);
1594         case 'S': {
1595                 const union {
1596                         struct sockaddr         raw;
1597                         struct sockaddr_in      v4;
1598                         struct sockaddr_in6     v6;
1599                 } *sa = ptr;
1600
1601                 switch (sa->raw.sa_family) {
1602                 case AF_INET:
1603                         return ip4_addr_string_sa(buf, end, &sa->v4, spec, fmt);
1604                 case AF_INET6:
1605                         return ip6_addr_string_sa(buf, end, &sa->v6, spec, fmt);
1606                 default:
1607                         return error_string(buf, end, "(einval)", spec);
1608                 }}
1609         }
1610
1611         err_fmt_msg = fmt[0] == 'i' ? "(%pi?)" : "(%pI?)";
1612         return error_string(buf, end, err_fmt_msg, spec);
1613 }
1614
1615 static noinline_for_stack
1616 char *escaped_string(char *buf, char *end, u8 *addr, struct printf_spec spec,
1617                      const char *fmt)
1618 {
1619         bool found = true;
1620         int count = 1;
1621         unsigned int flags = 0;
1622         int len;
1623
1624         if (spec.field_width == 0)
1625                 return buf;                             /* nothing to print */
1626
1627         if (check_pointer(&buf, end, addr, spec))
1628                 return buf;
1629
1630         do {
1631                 switch (fmt[count++]) {
1632                 case 'a':
1633                         flags |= ESCAPE_ANY;
1634                         break;
1635                 case 'c':
1636                         flags |= ESCAPE_SPECIAL;
1637                         break;
1638                 case 'h':
1639                         flags |= ESCAPE_HEX;
1640                         break;
1641                 case 'n':
1642                         flags |= ESCAPE_NULL;
1643                         break;
1644                 case 'o':
1645                         flags |= ESCAPE_OCTAL;
1646                         break;
1647                 case 'p':
1648                         flags |= ESCAPE_NP;
1649                         break;
1650                 case 's':
1651                         flags |= ESCAPE_SPACE;
1652                         break;
1653                 default:
1654                         found = false;
1655                         break;
1656                 }
1657         } while (found);
1658
1659         if (!flags)
1660                 flags = ESCAPE_ANY_NP;
1661
1662         len = spec.field_width < 0 ? 1 : spec.field_width;
1663
1664         /*
1665          * string_escape_mem() writes as many characters as it can to
1666          * the given buffer, and returns the total size of the output
1667          * had the buffer been big enough.
1668          */
1669         buf += string_escape_mem(addr, len, buf, buf < end ? end - buf : 0, flags, NULL);
1670
1671         return buf;
1672 }
1673
1674 static char *va_format(char *buf, char *end, struct va_format *va_fmt,
1675                        struct printf_spec spec, const char *fmt)
1676 {
1677         va_list va;
1678
1679         if (check_pointer(&buf, end, va_fmt, spec))
1680                 return buf;
1681
1682         va_copy(va, *va_fmt->va);
1683         buf += vsnprintf(buf, end > buf ? end - buf : 0, va_fmt->fmt, va);
1684         va_end(va);
1685
1686         return buf;
1687 }
1688
1689 static noinline_for_stack
1690 char *uuid_string(char *buf, char *end, const u8 *addr,
1691                   struct printf_spec spec, const char *fmt)
1692 {
1693         char uuid[UUID_STRING_LEN + 1];
1694         char *p = uuid;
1695         int i;
1696         const u8 *index = uuid_index;
1697         bool uc = false;
1698
1699         if (check_pointer(&buf, end, addr, spec))
1700                 return buf;
1701
1702         switch (*(++fmt)) {
1703         case 'L':
1704                 uc = true;
1705                 fallthrough;
1706         case 'l':
1707                 index = guid_index;
1708                 break;
1709         case 'B':
1710                 uc = true;
1711                 break;
1712         }
1713
1714         for (i = 0; i < 16; i++) {
1715                 if (uc)
1716                         p = hex_byte_pack_upper(p, addr[index[i]]);
1717                 else
1718                         p = hex_byte_pack(p, addr[index[i]]);
1719                 switch (i) {
1720                 case 3:
1721                 case 5:
1722                 case 7:
1723                 case 9:
1724                         *p++ = '-';
1725                         break;
1726                 }
1727         }
1728
1729         *p = 0;
1730
1731         return string_nocheck(buf, end, uuid, spec);
1732 }
1733
1734 static noinline_for_stack
1735 char *netdev_bits(char *buf, char *end, const void *addr,
1736                   struct printf_spec spec,  const char *fmt)
1737 {
1738         unsigned long long num;
1739         int size;
1740
1741         if (check_pointer(&buf, end, addr, spec))
1742                 return buf;
1743
1744         switch (fmt[1]) {
1745         case 'F':
1746                 num = *(const netdev_features_t *)addr;
1747                 size = sizeof(netdev_features_t);
1748                 break;
1749         default:
1750                 return error_string(buf, end, "(%pN?)", spec);
1751         }
1752
1753         return special_hex_number(buf, end, num, size);
1754 }
1755
1756 static noinline_for_stack
1757 char *fourcc_string(char *buf, char *end, const u32 *fourcc,
1758                     struct printf_spec spec, const char *fmt)
1759 {
1760         char output[sizeof("0123 little-endian (0x01234567)")];
1761         char *p = output;
1762         unsigned int i;
1763         u32 orig, val;
1764
1765         if (fmt[1] != 'c' || fmt[2] != 'c')
1766                 return error_string(buf, end, "(%p4?)", spec);
1767
1768         if (check_pointer(&buf, end, fourcc, spec))
1769                 return buf;
1770
1771         orig = get_unaligned(fourcc);
1772         val = orig & ~BIT(31);
1773
1774         for (i = 0; i < sizeof(u32); i++) {
1775                 unsigned char c = val >> (i * 8);
1776
1777                 /* Print non-control ASCII characters as-is, dot otherwise */
1778                 *p++ = isascii(c) && isprint(c) ? c : '.';
1779         }
1780
1781         *p++ = ' ';
1782         strcpy(p, orig & BIT(31) ? "big-endian" : "little-endian");
1783         p += strlen(p);
1784
1785         *p++ = ' ';
1786         *p++ = '(';
1787         p = special_hex_number(p, output + sizeof(output) - 2, orig, sizeof(u32));
1788         *p++ = ')';
1789         *p = '\0';
1790
1791         return string(buf, end, output, spec);
1792 }
1793
1794 static noinline_for_stack
1795 char *address_val(char *buf, char *end, const void *addr,
1796                   struct printf_spec spec, const char *fmt)
1797 {
1798         unsigned long long num;
1799         int size;
1800
1801         if (check_pointer(&buf, end, addr, spec))
1802                 return buf;
1803
1804         switch (fmt[1]) {
1805         case 'd':
1806                 num = *(const dma_addr_t *)addr;
1807                 size = sizeof(dma_addr_t);
1808                 break;
1809         case 'p':
1810         default:
1811                 num = *(const phys_addr_t *)addr;
1812                 size = sizeof(phys_addr_t);
1813                 break;
1814         }
1815
1816         return special_hex_number(buf, end, num, size);
1817 }
1818
1819 static noinline_for_stack
1820 char *date_str(char *buf, char *end, const struct rtc_time *tm, bool r)
1821 {
1822         int year = tm->tm_year + (r ? 0 : 1900);
1823         int mon = tm->tm_mon + (r ? 0 : 1);
1824
1825         buf = number(buf, end, year, default_dec04_spec);
1826         if (buf < end)
1827                 *buf = '-';
1828         buf++;
1829
1830         buf = number(buf, end, mon, default_dec02_spec);
1831         if (buf < end)
1832                 *buf = '-';
1833         buf++;
1834
1835         return number(buf, end, tm->tm_mday, default_dec02_spec);
1836 }
1837
1838 static noinline_for_stack
1839 char *time_str(char *buf, char *end, const struct rtc_time *tm, bool r)
1840 {
1841         buf = number(buf, end, tm->tm_hour, default_dec02_spec);
1842         if (buf < end)
1843                 *buf = ':';
1844         buf++;
1845
1846         buf = number(buf, end, tm->tm_min, default_dec02_spec);
1847         if (buf < end)
1848                 *buf = ':';
1849         buf++;
1850
1851         return number(buf, end, tm->tm_sec, default_dec02_spec);
1852 }
1853
1854 static noinline_for_stack
1855 char *rtc_str(char *buf, char *end, const struct rtc_time *tm,
1856               struct printf_spec spec, const char *fmt)
1857 {
1858         bool have_t = true, have_d = true;
1859         bool raw = false, iso8601_separator = true;
1860         bool found = true;
1861         int count = 2;
1862
1863         if (check_pointer(&buf, end, tm, spec))
1864                 return buf;
1865
1866         switch (fmt[count]) {
1867         case 'd':
1868                 have_t = false;
1869                 count++;
1870                 break;
1871         case 't':
1872                 have_d = false;
1873                 count++;
1874                 break;
1875         }
1876
1877         do {
1878                 switch (fmt[count++]) {
1879                 case 'r':
1880                         raw = true;
1881                         break;
1882                 case 's':
1883                         iso8601_separator = false;
1884                         break;
1885                 default:
1886                         found = false;
1887                         break;
1888                 }
1889         } while (found);
1890
1891         if (have_d)
1892                 buf = date_str(buf, end, tm, raw);
1893         if (have_d && have_t) {
1894                 if (buf < end)
1895                         *buf = iso8601_separator ? 'T' : ' ';
1896                 buf++;
1897         }
1898         if (have_t)
1899                 buf = time_str(buf, end, tm, raw);
1900
1901         return buf;
1902 }
1903
1904 static noinline_for_stack
1905 char *time64_str(char *buf, char *end, const time64_t time,
1906                  struct printf_spec spec, const char *fmt)
1907 {
1908         struct rtc_time rtc_time;
1909         struct tm tm;
1910
1911         time64_to_tm(time, 0, &tm);
1912
1913         rtc_time.tm_sec = tm.tm_sec;
1914         rtc_time.tm_min = tm.tm_min;
1915         rtc_time.tm_hour = tm.tm_hour;
1916         rtc_time.tm_mday = tm.tm_mday;
1917         rtc_time.tm_mon = tm.tm_mon;
1918         rtc_time.tm_year = tm.tm_year;
1919         rtc_time.tm_wday = tm.tm_wday;
1920         rtc_time.tm_yday = tm.tm_yday;
1921
1922         rtc_time.tm_isdst = 0;
1923
1924         return rtc_str(buf, end, &rtc_time, spec, fmt);
1925 }
1926
1927 static noinline_for_stack
1928 char *time_and_date(char *buf, char *end, void *ptr, struct printf_spec spec,
1929                     const char *fmt)
1930 {
1931         switch (fmt[1]) {
1932         case 'R':
1933                 return rtc_str(buf, end, (const struct rtc_time *)ptr, spec, fmt);
1934         case 'T':
1935                 return time64_str(buf, end, *(const time64_t *)ptr, spec, fmt);
1936         default:
1937                 return error_string(buf, end, "(%pt?)", spec);
1938         }
1939 }
1940
1941 static noinline_for_stack
1942 char *clock(char *buf, char *end, struct clk *clk, struct printf_spec spec,
1943             const char *fmt)
1944 {
1945         if (!IS_ENABLED(CONFIG_HAVE_CLK))
1946                 return error_string(buf, end, "(%pC?)", spec);
1947
1948         if (check_pointer(&buf, end, clk, spec))
1949                 return buf;
1950
1951         switch (fmt[1]) {
1952         case 'n':
1953         default:
1954 #ifdef CONFIG_COMMON_CLK
1955                 return string(buf, end, __clk_get_name(clk), spec);
1956 #else
1957                 return ptr_to_id(buf, end, clk, spec);
1958 #endif
1959         }
1960 }
1961
1962 static
1963 char *format_flags(char *buf, char *end, unsigned long flags,
1964                                         const struct trace_print_flags *names)
1965 {
1966         unsigned long mask;
1967
1968         for ( ; flags && names->name; names++) {
1969                 mask = names->mask;
1970                 if ((flags & mask) != mask)
1971                         continue;
1972
1973                 buf = string(buf, end, names->name, default_str_spec);
1974
1975                 flags &= ~mask;
1976                 if (flags) {
1977                         if (buf < end)
1978                                 *buf = '|';
1979                         buf++;
1980                 }
1981         }
1982
1983         if (flags)
1984                 buf = number(buf, end, flags, default_flag_spec);
1985
1986         return buf;
1987 }
1988
1989 struct page_flags_fields {
1990         int width;
1991         int shift;
1992         int mask;
1993         const struct printf_spec *spec;
1994         const char *name;
1995 };
1996
1997 static const struct page_flags_fields pff[] = {
1998         {SECTIONS_WIDTH, SECTIONS_PGSHIFT, SECTIONS_MASK,
1999          &default_dec_spec, "section"},
2000         {NODES_WIDTH, NODES_PGSHIFT, NODES_MASK,
2001          &default_dec_spec, "node"},
2002         {ZONES_WIDTH, ZONES_PGSHIFT, ZONES_MASK,
2003          &default_dec_spec, "zone"},
2004         {LAST_CPUPID_WIDTH, LAST_CPUPID_PGSHIFT, LAST_CPUPID_MASK,
2005          &default_flag_spec, "lastcpupid"},
2006         {KASAN_TAG_WIDTH, KASAN_TAG_PGSHIFT, KASAN_TAG_MASK,
2007          &default_flag_spec, "kasantag"},
2008 };
2009
2010 static
2011 char *format_page_flags(char *buf, char *end, unsigned long flags)
2012 {
2013         unsigned long main_flags = flags & PAGEFLAGS_MASK;
2014         bool append = false;
2015         int i;
2016
2017         buf = number(buf, end, flags, default_flag_spec);
2018         if (buf < end)
2019                 *buf = '(';
2020         buf++;
2021
2022         /* Page flags from the main area. */
2023         if (main_flags) {
2024                 buf = format_flags(buf, end, main_flags, pageflag_names);
2025                 append = true;
2026         }
2027
2028         /* Page flags from the fields area */
2029         for (i = 0; i < ARRAY_SIZE(pff); i++) {
2030                 /* Skip undefined fields. */
2031                 if (!pff[i].width)
2032                         continue;
2033
2034                 /* Format: Flag Name + '=' (equals sign) + Number + '|' (separator) */
2035                 if (append) {
2036                         if (buf < end)
2037                                 *buf = '|';
2038                         buf++;
2039                 }
2040
2041                 buf = string(buf, end, pff[i].name, default_str_spec);
2042                 if (buf < end)
2043                         *buf = '=';
2044                 buf++;
2045                 buf = number(buf, end, (flags >> pff[i].shift) & pff[i].mask,
2046                              *pff[i].spec);
2047
2048                 append = true;
2049         }
2050         if (buf < end)
2051                 *buf = ')';
2052         buf++;
2053
2054         return buf;
2055 }
2056
2057 static noinline_for_stack
2058 char *flags_string(char *buf, char *end, void *flags_ptr,
2059                    struct printf_spec spec, const char *fmt)
2060 {
2061         unsigned long flags;
2062         const struct trace_print_flags *names;
2063
2064         if (check_pointer(&buf, end, flags_ptr, spec))
2065                 return buf;
2066
2067         switch (fmt[1]) {
2068         case 'p':
2069                 return format_page_flags(buf, end, *(unsigned long *)flags_ptr);
2070         case 'v':
2071                 flags = *(unsigned long *)flags_ptr;
2072                 names = vmaflag_names;
2073                 break;
2074         case 'g':
2075                 flags = (__force unsigned long)(*(gfp_t *)flags_ptr);
2076                 names = gfpflag_names;
2077                 break;
2078         default:
2079                 return error_string(buf, end, "(%pG?)", spec);
2080         }
2081
2082         return format_flags(buf, end, flags, names);
2083 }
2084
2085 static noinline_for_stack
2086 char *fwnode_full_name_string(struct fwnode_handle *fwnode, char *buf,
2087                               char *end)
2088 {
2089         int depth;
2090
2091         /* Loop starting from the root node to the current node. */
2092         for (depth = fwnode_count_parents(fwnode); depth >= 0; depth--) {
2093                 /*
2094                  * Only get a reference for other nodes (i.e. parent nodes).
2095                  * fwnode refcount may be 0 here.
2096                  */
2097                 struct fwnode_handle *__fwnode = depth ?
2098                         fwnode_get_nth_parent(fwnode, depth) : fwnode;
2099
2100                 buf = string(buf, end, fwnode_get_name_prefix(__fwnode),
2101                              default_str_spec);
2102                 buf = string(buf, end, fwnode_get_name(__fwnode),
2103                              default_str_spec);
2104
2105                 if (depth)
2106                         fwnode_handle_put(__fwnode);
2107         }
2108
2109         return buf;
2110 }
2111
2112 static noinline_for_stack
2113 char *device_node_string(char *buf, char *end, struct device_node *dn,
2114                          struct printf_spec spec, const char *fmt)
2115 {
2116         char tbuf[sizeof("xxxx") + 1];
2117         const char *p;
2118         int ret;
2119         char *buf_start = buf;
2120         struct property *prop;
2121         bool has_mult, pass;
2122
2123         struct printf_spec str_spec = spec;
2124         str_spec.field_width = -1;
2125
2126         if (fmt[0] != 'F')
2127                 return error_string(buf, end, "(%pO?)", spec);
2128
2129         if (!IS_ENABLED(CONFIG_OF))
2130                 return error_string(buf, end, "(%pOF?)", spec);
2131
2132         if (check_pointer(&buf, end, dn, spec))
2133                 return buf;
2134
2135         /* simple case without anything any more format specifiers */
2136         fmt++;
2137         if (fmt[0] == '\0' || strcspn(fmt,"fnpPFcC") > 0)
2138                 fmt = "f";
2139
2140         for (pass = false; strspn(fmt,"fnpPFcC"); fmt++, pass = true) {
2141                 int precision;
2142                 if (pass) {
2143                         if (buf < end)
2144                                 *buf = ':';
2145                         buf++;
2146                 }
2147
2148                 switch (*fmt) {
2149                 case 'f':       /* full_name */
2150                         buf = fwnode_full_name_string(of_fwnode_handle(dn), buf,
2151                                                       end);
2152                         break;
2153                 case 'n':       /* name */
2154                         p = fwnode_get_name(of_fwnode_handle(dn));
2155                         precision = str_spec.precision;
2156                         str_spec.precision = strchrnul(p, '@') - p;
2157                         buf = string(buf, end, p, str_spec);
2158                         str_spec.precision = precision;
2159                         break;
2160                 case 'p':       /* phandle */
2161                         buf = number(buf, end, (unsigned int)dn->phandle, default_dec_spec);
2162                         break;
2163                 case 'P':       /* path-spec */
2164                         p = fwnode_get_name(of_fwnode_handle(dn));
2165                         if (!p[1])
2166                                 p = "/";
2167                         buf = string(buf, end, p, str_spec);
2168                         break;
2169                 case 'F':       /* flags */
2170                         tbuf[0] = of_node_check_flag(dn, OF_DYNAMIC) ? 'D' : '-';
2171                         tbuf[1] = of_node_check_flag(dn, OF_DETACHED) ? 'd' : '-';
2172                         tbuf[2] = of_node_check_flag(dn, OF_POPULATED) ? 'P' : '-';
2173                         tbuf[3] = of_node_check_flag(dn, OF_POPULATED_BUS) ? 'B' : '-';
2174                         tbuf[4] = 0;
2175                         buf = string_nocheck(buf, end, tbuf, str_spec);
2176                         break;
2177                 case 'c':       /* major compatible string */
2178                         ret = of_property_read_string(dn, "compatible", &p);
2179                         if (!ret)
2180                                 buf = string(buf, end, p, str_spec);
2181                         break;
2182                 case 'C':       /* full compatible string */
2183                         has_mult = false;
2184                         of_property_for_each_string(dn, "compatible", prop, p) {
2185                                 if (has_mult)
2186                                         buf = string_nocheck(buf, end, ",", str_spec);
2187                                 buf = string_nocheck(buf, end, "\"", str_spec);
2188                                 buf = string(buf, end, p, str_spec);
2189                                 buf = string_nocheck(buf, end, "\"", str_spec);
2190
2191                                 has_mult = true;
2192                         }
2193                         break;
2194                 default:
2195                         break;
2196                 }
2197         }
2198
2199         return widen_string(buf, buf - buf_start, end, spec);
2200 }
2201
2202 static noinline_for_stack
2203 char *fwnode_string(char *buf, char *end, struct fwnode_handle *fwnode,
2204                     struct printf_spec spec, const char *fmt)
2205 {
2206         struct printf_spec str_spec = spec;
2207         char *buf_start = buf;
2208
2209         str_spec.field_width = -1;
2210
2211         if (*fmt != 'w')
2212                 return error_string(buf, end, "(%pf?)", spec);
2213
2214         if (check_pointer(&buf, end, fwnode, spec))
2215                 return buf;
2216
2217         fmt++;
2218
2219         switch (*fmt) {
2220         case 'P':       /* name */
2221                 buf = string(buf, end, fwnode_get_name(fwnode), str_spec);
2222                 break;
2223         case 'f':       /* full_name */
2224         default:
2225                 buf = fwnode_full_name_string(fwnode, buf, end);
2226                 break;
2227         }
2228
2229         return widen_string(buf, buf - buf_start, end, spec);
2230 }
2231
2232 int __init no_hash_pointers_enable(char *str)
2233 {
2234         if (no_hash_pointers)
2235                 return 0;
2236
2237         no_hash_pointers = true;
2238
2239         pr_warn("**********************************************************\n");
2240         pr_warn("**   NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE   **\n");
2241         pr_warn("**                                                      **\n");
2242         pr_warn("** This system shows unhashed kernel memory addresses   **\n");
2243         pr_warn("** via the console, logs, and other interfaces. This    **\n");
2244         pr_warn("** might reduce the security of your system.            **\n");
2245         pr_warn("**                                                      **\n");
2246         pr_warn("** If you see this message and you are not debugging    **\n");
2247         pr_warn("** the kernel, report this immediately to your system   **\n");
2248         pr_warn("** administrator!                                       **\n");
2249         pr_warn("**                                                      **\n");
2250         pr_warn("**   NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE   **\n");
2251         pr_warn("**********************************************************\n");
2252
2253         return 0;
2254 }
2255 early_param("no_hash_pointers", no_hash_pointers_enable);
2256
2257 /* Used for Rust formatting ('%pA'). */
2258 char *rust_fmt_argument(char *buf, char *end, void *ptr);
2259
2260 /*
2261  * Show a '%p' thing.  A kernel extension is that the '%p' is followed
2262  * by an extra set of alphanumeric characters that are extended format
2263  * specifiers.
2264  *
2265  * Please update scripts/checkpatch.pl when adding/removing conversion
2266  * characters.  (Search for "check for vsprintf extension").
2267  *
2268  * Right now we handle:
2269  *
2270  * - 'S' For symbolic direct pointers (or function descriptors) with offset
2271  * - 's' For symbolic direct pointers (or function descriptors) without offset
2272  * - '[Ss]R' as above with __builtin_extract_return_addr() translation
2273  * - 'S[R]b' as above with module build ID (for use in backtraces)
2274  * - '[Ff]' %pf and %pF were obsoleted and later removed in favor of
2275  *          %ps and %pS. Be careful when re-using these specifiers.
2276  * - 'B' For backtraced symbolic direct pointers with offset
2277  * - 'Bb' as above with module build ID (for use in backtraces)
2278  * - 'R' For decoded struct resource, e.g., [mem 0x0-0x1f 64bit pref]
2279  * - 'r' For raw struct resource, e.g., [mem 0x0-0x1f flags 0x201]
2280  * - 'b[l]' For a bitmap, the number of bits is determined by the field
2281  *       width which must be explicitly specified either as part of the
2282  *       format string '%32b[l]' or through '%*b[l]', [l] selects
2283  *       range-list format instead of hex format
2284  * - 'M' For a 6-byte MAC address, it prints the address in the
2285  *       usual colon-separated hex notation
2286  * - 'm' For a 6-byte MAC address, it prints the hex address without colons
2287  * - 'MF' For a 6-byte MAC FDDI address, it prints the address
2288  *       with a dash-separated hex notation
2289  * - '[mM]R' For a 6-byte MAC address, Reverse order (Bluetooth)
2290  * - 'I' [46] for IPv4/IPv6 addresses printed in the usual way
2291  *       IPv4 uses dot-separated decimal without leading 0's (1.2.3.4)
2292  *       IPv6 uses colon separated network-order 16 bit hex with leading 0's
2293  *       [S][pfs]
2294  *       Generic IPv4/IPv6 address (struct sockaddr *) that falls back to
2295  *       [4] or [6] and is able to print port [p], flowinfo [f], scope [s]
2296  * - 'i' [46] for 'raw' IPv4/IPv6 addresses
2297  *       IPv6 omits the colons (01020304...0f)
2298  *       IPv4 uses dot-separated decimal with leading 0's (010.123.045.006)
2299  *       [S][pfs]
2300  *       Generic IPv4/IPv6 address (struct sockaddr *) that falls back to
2301  *       [4] or [6] and is able to print port [p], flowinfo [f], scope [s]
2302  * - '[Ii][4S][hnbl]' IPv4 addresses in host, network, big or little endian order
2303  * - 'I[6S]c' for IPv6 addresses printed as specified by
2304  *       https://tools.ietf.org/html/rfc5952
2305  * - 'E[achnops]' For an escaped buffer, where rules are defined by combination
2306  *                of the following flags (see string_escape_mem() for the
2307  *                details):
2308  *                  a - ESCAPE_ANY
2309  *                  c - ESCAPE_SPECIAL
2310  *                  h - ESCAPE_HEX
2311  *                  n - ESCAPE_NULL
2312  *                  o - ESCAPE_OCTAL
2313  *                  p - ESCAPE_NP
2314  *                  s - ESCAPE_SPACE
2315  *                By default ESCAPE_ANY_NP is used.
2316  * - 'U' For a 16 byte UUID/GUID, it prints the UUID/GUID in the form
2317  *       "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx"
2318  *       Options for %pU are:
2319  *         b big endian lower case hex (default)
2320  *         B big endian UPPER case hex
2321  *         l little endian lower case hex
2322  *         L little endian UPPER case hex
2323  *           big endian output byte order is:
2324  *             [0][1][2][3]-[4][5]-[6][7]-[8][9]-[10][11][12][13][14][15]
2325  *           little endian output byte order is:
2326  *             [3][2][1][0]-[5][4]-[7][6]-[8][9]-[10][11][12][13][14][15]
2327  * - 'V' For a struct va_format which contains a format string * and va_list *,
2328  *       call vsnprintf(->format, *->va_list).
2329  *       Implements a "recursive vsnprintf".
2330  *       Do not use this feature without some mechanism to verify the
2331  *       correctness of the format string and va_list arguments.
2332  * - 'K' For a kernel pointer that should be hidden from unprivileged users.
2333  *       Use only for procfs, sysfs and similar files, not printk(); please
2334  *       read the documentation (path below) first.
2335  * - 'NF' For a netdev_features_t
2336  * - '4cc' V4L2 or DRM FourCC code, with endianness and raw numerical value.
2337  * - 'h[CDN]' For a variable-length buffer, it prints it as a hex string with
2338  *            a certain separator (' ' by default):
2339  *              C colon
2340  *              D dash
2341  *              N no separator
2342  *            The maximum supported length is 64 bytes of the input. Consider
2343  *            to use print_hex_dump() for the larger input.
2344  * - 'a[pd]' For address types [p] phys_addr_t, [d] dma_addr_t and derivatives
2345  *           (default assumed to be phys_addr_t, passed by reference)
2346  * - 'd[234]' For a dentry name (optionally 2-4 last components)
2347  * - 'D[234]' Same as 'd' but for a struct file
2348  * - 'g' For block_device name (gendisk + partition number)
2349  * - 't[RT][dt][r][s]' For time and date as represented by:
2350  *      R    struct rtc_time
2351  *      T    time64_t
2352  * - 'C' For a clock, it prints the name (Common Clock Framework) or address
2353  *       (legacy clock framework) of the clock
2354  * - 'Cn' For a clock, it prints the name (Common Clock Framework) or address
2355  *        (legacy clock framework) of the clock
2356  * - 'G' For flags to be printed as a collection of symbolic strings that would
2357  *       construct the specific value. Supported flags given by option:
2358  *       p page flags (see struct page) given as pointer to unsigned long
2359  *       g gfp flags (GFP_* and __GFP_*) given as pointer to gfp_t
2360  *       v vma flags (VM_*) given as pointer to unsigned long
2361  * - 'OF[fnpPcCF]'  For a device tree object
2362  *                  Without any optional arguments prints the full_name
2363  *                  f device node full_name
2364  *                  n device node name
2365  *                  p device node phandle
2366  *                  P device node path spec (name + @unit)
2367  *                  F device node flags
2368  *                  c major compatible string
2369  *                  C full compatible string
2370  * - 'fw[fP]'   For a firmware node (struct fwnode_handle) pointer
2371  *              Without an option prints the full name of the node
2372  *              f full name
2373  *              P node name, including a possible unit address
2374  * - 'x' For printing the address unmodified. Equivalent to "%lx".
2375  *       Please read the documentation (path below) before using!
2376  * - '[ku]s' For a BPF/tracing related format specifier, e.g. used out of
2377  *           bpf_trace_printk() where [ku] prefix specifies either kernel (k)
2378  *           or user (u) memory to probe, and:
2379  *              s a string, equivalent to "%s" on direct vsnprintf() use
2380  *
2381  * ** When making changes please also update:
2382  *      Documentation/core-api/printk-formats.rst
2383  *
2384  * Note: The default behaviour (unadorned %p) is to hash the address,
2385  * rendering it useful as a unique identifier.
2386  *
2387  * There is also a '%pA' format specifier, but it is only intended to be used
2388  * from Rust code to format core::fmt::Arguments. Do *not* use it from C.
2389  * See rust/kernel/print.rs for details.
2390  */
2391 static noinline_for_stack
2392 char *pointer(const char *fmt, char *buf, char *end, void *ptr,
2393               struct printf_spec spec)
2394 {
2395         switch (*fmt) {
2396         case 'S':
2397         case 's':
2398                 ptr = dereference_symbol_descriptor(ptr);
2399                 fallthrough;
2400         case 'B':
2401                 return symbol_string(buf, end, ptr, spec, fmt);
2402         case 'R':
2403         case 'r':
2404                 return resource_string(buf, end, ptr, spec, fmt);
2405         case 'h':
2406                 return hex_string(buf, end, ptr, spec, fmt);
2407         case 'b':
2408                 switch (fmt[1]) {
2409                 case 'l':
2410                         return bitmap_list_string(buf, end, ptr, spec, fmt);
2411                 default:
2412                         return bitmap_string(buf, end, ptr, spec, fmt);
2413                 }
2414         case 'M':                       /* Colon separated: 00:01:02:03:04:05 */
2415         case 'm':                       /* Contiguous: 000102030405 */
2416                                         /* [mM]F (FDDI) */
2417                                         /* [mM]R (Reverse order; Bluetooth) */
2418                 return mac_address_string(buf, end, ptr, spec, fmt);
2419         case 'I':                       /* Formatted IP supported
2420                                          * 4:   1.2.3.4
2421                                          * 6:   0001:0203:...:0708
2422                                          * 6c:  1::708 or 1::1.2.3.4
2423                                          */
2424         case 'i':                       /* Contiguous:
2425                                          * 4:   001.002.003.004
2426                                          * 6:   000102...0f
2427                                          */
2428                 return ip_addr_string(buf, end, ptr, spec, fmt);
2429         case 'E':
2430                 return escaped_string(buf, end, ptr, spec, fmt);
2431         case 'U':
2432                 return uuid_string(buf, end, ptr, spec, fmt);
2433         case 'V':
2434                 return va_format(buf, end, ptr, spec, fmt);
2435         case 'K':
2436                 return restricted_pointer(buf, end, ptr, spec);
2437         case 'N':
2438                 return netdev_bits(buf, end, ptr, spec, fmt);
2439         case '4':
2440                 return fourcc_string(buf, end, ptr, spec, fmt);
2441         case 'a':
2442                 return address_val(buf, end, ptr, spec, fmt);
2443         case 'd':
2444                 return dentry_name(buf, end, ptr, spec, fmt);
2445         case 't':
2446                 return time_and_date(buf, end, ptr, spec, fmt);
2447         case 'C':
2448                 return clock(buf, end, ptr, spec, fmt);
2449         case 'D':
2450                 return file_dentry_name(buf, end, ptr, spec, fmt);
2451 #ifdef CONFIG_BLOCK
2452         case 'g':
2453                 return bdev_name(buf, end, ptr, spec, fmt);
2454 #endif
2455
2456         case 'G':
2457                 return flags_string(buf, end, ptr, spec, fmt);
2458         case 'O':
2459                 return device_node_string(buf, end, ptr, spec, fmt + 1);
2460         case 'f':
2461                 return fwnode_string(buf, end, ptr, spec, fmt + 1);
2462         case 'A':
2463                 if (!IS_ENABLED(CONFIG_RUST)) {
2464                         WARN_ONCE(1, "Please remove %%pA from non-Rust code\n");
2465                         return error_string(buf, end, "(%pA?)", spec);
2466                 }
2467                 return rust_fmt_argument(buf, end, ptr);
2468         case 'x':
2469                 return pointer_string(buf, end, ptr, spec);
2470         case 'e':
2471                 /* %pe with a non-ERR_PTR gets treated as plain %p */
2472                 if (!IS_ERR(ptr))
2473                         return default_pointer(buf, end, ptr, spec);
2474                 return err_ptr(buf, end, ptr, spec);
2475         case 'u':
2476         case 'k':
2477                 switch (fmt[1]) {
2478                 case 's':
2479                         return string(buf, end, ptr, spec);
2480                 default:
2481                         return error_string(buf, end, "(einval)", spec);
2482                 }
2483         default:
2484                 return default_pointer(buf, end, ptr, spec);
2485         }
2486 }
2487
2488 /*
2489  * Helper function to decode printf style format.
2490  * Each call decode a token from the format and return the
2491  * number of characters read (or likely the delta where it wants
2492  * to go on the next call).
2493  * The decoded token is returned through the parameters
2494  *
2495  * 'h', 'l', or 'L' for integer fields
2496  * 'z' support added 23/7/1999 S.H.
2497  * 'z' changed to 'Z' --davidm 1/25/99
2498  * 'Z' changed to 'z' --adobriyan 2017-01-25
2499  * 't' added for ptrdiff_t
2500  *
2501  * @fmt: the format string
2502  * @type of the token returned
2503  * @flags: various flags such as +, -, # tokens..
2504  * @field_width: overwritten width
2505  * @base: base of the number (octal, hex, ...)
2506  * @precision: precision of a number
2507  * @qualifier: qualifier of a number (long, size_t, ...)
2508  */
2509 static noinline_for_stack
2510 int format_decode(const char *fmt, struct printf_spec *spec)
2511 {
2512         const char *start = fmt;
2513         char qualifier;
2514
2515         /* we finished early by reading the field width */
2516         if (spec->type == FORMAT_TYPE_WIDTH) {
2517                 if (spec->field_width < 0) {
2518                         spec->field_width = -spec->field_width;
2519                         spec->flags |= LEFT;
2520                 }
2521                 spec->type = FORMAT_TYPE_NONE;
2522                 goto precision;
2523         }
2524
2525         /* we finished early by reading the precision */
2526         if (spec->type == FORMAT_TYPE_PRECISION) {
2527                 if (spec->precision < 0)
2528                         spec->precision = 0;
2529
2530                 spec->type = FORMAT_TYPE_NONE;
2531                 goto qualifier;
2532         }
2533
2534         /* By default */
2535         spec->type = FORMAT_TYPE_NONE;
2536
2537         for (; *fmt ; ++fmt) {
2538                 if (*fmt == '%')
2539                         break;
2540         }
2541
2542         /* Return the current non-format string */
2543         if (fmt != start || !*fmt)
2544                 return fmt - start;
2545
2546         /* Process flags */
2547         spec->flags = 0;
2548
2549         while (1) { /* this also skips first '%' */
2550                 bool found = true;
2551
2552                 ++fmt;
2553
2554                 switch (*fmt) {
2555                 case '-': spec->flags |= LEFT;    break;
2556                 case '+': spec->flags |= PLUS;    break;
2557                 case ' ': spec->flags |= SPACE;   break;
2558                 case '#': spec->flags |= SPECIAL; break;
2559                 case '0': spec->flags |= ZEROPAD; break;
2560                 default:  found = false;
2561                 }
2562
2563                 if (!found)
2564                         break;
2565         }
2566
2567         /* get field width */
2568         spec->field_width = -1;
2569
2570         if (isdigit(*fmt))
2571                 spec->field_width = skip_atoi(&fmt);
2572         else if (*fmt == '*') {
2573                 /* it's the next argument */
2574                 spec->type = FORMAT_TYPE_WIDTH;
2575                 return ++fmt - start;
2576         }
2577
2578 precision:
2579         /* get the precision */
2580         spec->precision = -1;
2581         if (*fmt == '.') {
2582                 ++fmt;
2583                 if (isdigit(*fmt)) {
2584                         spec->precision = skip_atoi(&fmt);
2585                         if (spec->precision < 0)
2586                                 spec->precision = 0;
2587                 } else if (*fmt == '*') {
2588                         /* it's the next argument */
2589                         spec->type = FORMAT_TYPE_PRECISION;
2590                         return ++fmt - start;
2591                 }
2592         }
2593
2594 qualifier:
2595         /* get the conversion qualifier */
2596         qualifier = 0;
2597         if (*fmt == 'h' || _tolower(*fmt) == 'l' ||
2598             *fmt == 'z' || *fmt == 't') {
2599                 qualifier = *fmt++;
2600                 if (unlikely(qualifier == *fmt)) {
2601                         if (qualifier == 'l') {
2602                                 qualifier = 'L';
2603                                 ++fmt;
2604                         } else if (qualifier == 'h') {
2605                                 qualifier = 'H';
2606                                 ++fmt;
2607                         }
2608                 }
2609         }
2610
2611         /* default base */
2612         spec->base = 10;
2613         switch (*fmt) {
2614         case 'c':
2615                 spec->type = FORMAT_TYPE_CHAR;
2616                 return ++fmt - start;
2617
2618         case 's':
2619                 spec->type = FORMAT_TYPE_STR;
2620                 return ++fmt - start;
2621
2622         case 'p':
2623                 spec->type = FORMAT_TYPE_PTR;
2624                 return ++fmt - start;
2625
2626         case '%':
2627                 spec->type = FORMAT_TYPE_PERCENT_CHAR;
2628                 return ++fmt - start;
2629
2630         /* integer number formats - set up the flags and "break" */
2631         case 'o':
2632                 spec->base = 8;
2633                 break;
2634
2635         case 'x':
2636                 spec->flags |= SMALL;
2637                 fallthrough;
2638
2639         case 'X':
2640                 spec->base = 16;
2641                 break;
2642
2643         case 'd':
2644         case 'i':
2645                 spec->flags |= SIGN;
2646                 break;
2647         case 'u':
2648                 break;
2649
2650         case 'n':
2651                 /*
2652                  * Since %n poses a greater security risk than
2653                  * utility, treat it as any other invalid or
2654                  * unsupported format specifier.
2655                  */
2656                 fallthrough;
2657
2658         default:
2659                 WARN_ONCE(1, "Please remove unsupported %%%c in format string\n", *fmt);
2660                 spec->type = FORMAT_TYPE_INVALID;
2661                 return fmt - start;
2662         }
2663
2664         if (qualifier == 'L')
2665                 spec->type = FORMAT_TYPE_LONG_LONG;
2666         else if (qualifier == 'l') {
2667                 BUILD_BUG_ON(FORMAT_TYPE_ULONG + SIGN != FORMAT_TYPE_LONG);
2668                 spec->type = FORMAT_TYPE_ULONG + (spec->flags & SIGN);
2669         } else if (qualifier == 'z') {
2670                 spec->type = FORMAT_TYPE_SIZE_T;
2671         } else if (qualifier == 't') {
2672                 spec->type = FORMAT_TYPE_PTRDIFF;
2673         } else if (qualifier == 'H') {
2674                 BUILD_BUG_ON(FORMAT_TYPE_UBYTE + SIGN != FORMAT_TYPE_BYTE);
2675                 spec->type = FORMAT_TYPE_UBYTE + (spec->flags & SIGN);
2676         } else if (qualifier == 'h') {
2677                 BUILD_BUG_ON(FORMAT_TYPE_USHORT + SIGN != FORMAT_TYPE_SHORT);
2678                 spec->type = FORMAT_TYPE_USHORT + (spec->flags & SIGN);
2679         } else {
2680                 BUILD_BUG_ON(FORMAT_TYPE_UINT + SIGN != FORMAT_TYPE_INT);
2681                 spec->type = FORMAT_TYPE_UINT + (spec->flags & SIGN);
2682         }
2683
2684         return ++fmt - start;
2685 }
2686
2687 static void
2688 set_field_width(struct printf_spec *spec, int width)
2689 {
2690         spec->field_width = width;
2691         if (WARN_ONCE(spec->field_width != width, "field width %d too large", width)) {
2692                 spec->field_width = clamp(width, -FIELD_WIDTH_MAX, FIELD_WIDTH_MAX);
2693         }
2694 }
2695
2696 static void
2697 set_precision(struct printf_spec *spec, int prec)
2698 {
2699         spec->precision = prec;
2700         if (WARN_ONCE(spec->precision != prec, "precision %d too large", prec)) {
2701                 spec->precision = clamp(prec, 0, PRECISION_MAX);
2702         }
2703 }
2704
2705 /**
2706  * vsnprintf - Format a string and place it in a buffer
2707  * @buf: The buffer to place the result into
2708  * @size: The size of the buffer, including the trailing null space
2709  * @fmt: The format string to use
2710  * @args: Arguments for the format string
2711  *
2712  * This function generally follows C99 vsnprintf, but has some
2713  * extensions and a few limitations:
2714  *
2715  *  - ``%n`` is unsupported
2716  *  - ``%p*`` is handled by pointer()
2717  *
2718  * See pointer() or Documentation/core-api/printk-formats.rst for more
2719  * extensive description.
2720  *
2721  * **Please update the documentation in both places when making changes**
2722  *
2723  * The return value is the number of characters which would
2724  * be generated for the given input, excluding the trailing
2725  * '\0', as per ISO C99. If you want to have the exact
2726  * number of characters written into @buf as return value
2727  * (not including the trailing '\0'), use vscnprintf(). If the
2728  * return is greater than or equal to @size, the resulting
2729  * string is truncated.
2730  *
2731  * If you're not already dealing with a va_list consider using snprintf().
2732  */
2733 int vsnprintf(char *buf, size_t size, const char *fmt, va_list args)
2734 {
2735         unsigned long long num;
2736         char *str, *end;
2737         struct printf_spec spec = {0};
2738
2739         /* Reject out-of-range values early.  Large positive sizes are
2740            used for unknown buffer sizes. */
2741         if (WARN_ON_ONCE(size > INT_MAX))
2742                 return 0;
2743
2744         str = buf;
2745         end = buf + size;
2746
2747         /* Make sure end is always >= buf */
2748         if (end < buf) {
2749                 end = ((void *)-1);
2750                 size = end - buf;
2751         }
2752
2753         while (*fmt) {
2754                 const char *old_fmt = fmt;
2755                 int read = format_decode(fmt, &spec);
2756
2757                 fmt += read;
2758
2759                 switch (spec.type) {
2760                 case FORMAT_TYPE_NONE: {
2761                         int copy = read;
2762                         if (str < end) {
2763                                 if (copy > end - str)
2764                                         copy = end - str;
2765                                 memcpy(str, old_fmt, copy);
2766                         }
2767                         str += read;
2768                         break;
2769                 }
2770
2771                 case FORMAT_TYPE_WIDTH:
2772                         set_field_width(&spec, va_arg(args, int));
2773                         break;
2774
2775                 case FORMAT_TYPE_PRECISION:
2776                         set_precision(&spec, va_arg(args, int));
2777                         break;
2778
2779                 case FORMAT_TYPE_CHAR: {
2780                         char c;
2781
2782                         if (!(spec.flags & LEFT)) {
2783                                 while (--spec.field_width > 0) {
2784                                         if (str < end)
2785                                                 *str = ' ';
2786                                         ++str;
2787
2788                                 }
2789                         }
2790                         c = (unsigned char) va_arg(args, int);
2791                         if (str < end)
2792                                 *str = c;
2793                         ++str;
2794                         while (--spec.field_width > 0) {
2795                                 if (str < end)
2796                                         *str = ' ';
2797                                 ++str;
2798                         }
2799                         break;
2800                 }
2801
2802                 case FORMAT_TYPE_STR:
2803                         str = string(str, end, va_arg(args, char *), spec);
2804                         break;
2805
2806                 case FORMAT_TYPE_PTR:
2807                         str = pointer(fmt, str, end, va_arg(args, void *),
2808                                       spec);
2809                         while (isalnum(*fmt))
2810                                 fmt++;
2811                         break;
2812
2813                 case FORMAT_TYPE_PERCENT_CHAR:
2814                         if (str < end)
2815                                 *str = '%';
2816                         ++str;
2817                         break;
2818
2819                 case FORMAT_TYPE_INVALID:
2820                         /*
2821                          * Presumably the arguments passed gcc's type
2822                          * checking, but there is no safe or sane way
2823                          * for us to continue parsing the format and
2824                          * fetching from the va_list; the remaining
2825                          * specifiers and arguments would be out of
2826                          * sync.
2827                          */
2828                         goto out;
2829
2830                 default:
2831                         switch (spec.type) {
2832                         case FORMAT_TYPE_LONG_LONG:
2833                                 num = va_arg(args, long long);
2834                                 break;
2835                         case FORMAT_TYPE_ULONG:
2836                                 num = va_arg(args, unsigned long);
2837                                 break;
2838                         case FORMAT_TYPE_LONG:
2839                                 num = va_arg(args, long);
2840                                 break;
2841                         case FORMAT_TYPE_SIZE_T:
2842                                 if (spec.flags & SIGN)
2843                                         num = va_arg(args, ssize_t);
2844                                 else
2845                                         num = va_arg(args, size_t);
2846                                 break;
2847                         case FORMAT_TYPE_PTRDIFF:
2848                                 num = va_arg(args, ptrdiff_t);
2849                                 break;
2850                         case FORMAT_TYPE_UBYTE:
2851                                 num = (unsigned char) va_arg(args, int);
2852                                 break;
2853                         case FORMAT_TYPE_BYTE:
2854                                 num = (signed char) va_arg(args, int);
2855                                 break;
2856                         case FORMAT_TYPE_USHORT:
2857                                 num = (unsigned short) va_arg(args, int);
2858                                 break;
2859                         case FORMAT_TYPE_SHORT:
2860                                 num = (short) va_arg(args, int);
2861                                 break;
2862                         case FORMAT_TYPE_INT:
2863                                 num = (int) va_arg(args, int);
2864                                 break;
2865                         default:
2866                                 num = va_arg(args, unsigned int);
2867                         }
2868
2869                         str = number(str, end, num, spec);
2870                 }
2871         }
2872
2873 out:
2874         if (size > 0) {
2875                 if (str < end)
2876                         *str = '\0';
2877                 else
2878                         end[-1] = '\0';
2879         }
2880
2881         /* the trailing null byte doesn't count towards the total */
2882         return str-buf;
2883
2884 }
2885 EXPORT_SYMBOL(vsnprintf);
2886
2887 /**
2888  * vscnprintf - Format a string and place it in a buffer
2889  * @buf: The buffer to place the result into
2890  * @size: The size of the buffer, including the trailing null space
2891  * @fmt: The format string to use
2892  * @args: Arguments for the format string
2893  *
2894  * The return value is the number of characters which have been written into
2895  * the @buf not including the trailing '\0'. If @size is == 0 the function
2896  * returns 0.
2897  *
2898  * If you're not already dealing with a va_list consider using scnprintf().
2899  *
2900  * See the vsnprintf() documentation for format string extensions over C99.
2901  */
2902 int vscnprintf(char *buf, size_t size, const char *fmt, va_list args)
2903 {
2904         int i;
2905
2906         if (unlikely(!size))
2907                 return 0;
2908
2909         i = vsnprintf(buf, size, fmt, args);
2910
2911         if (likely(i < size))
2912                 return i;
2913
2914         return size - 1;
2915 }
2916 EXPORT_SYMBOL(vscnprintf);
2917
2918 /**
2919  * snprintf - Format a string and place it in a buffer
2920  * @buf: The buffer to place the result into
2921  * @size: The size of the buffer, including the trailing null space
2922  * @fmt: The format string to use
2923  * @...: Arguments for the format string
2924  *
2925  * The return value is the number of characters which would be
2926  * generated for the given input, excluding the trailing null,
2927  * as per ISO C99.  If the return is greater than or equal to
2928  * @size, the resulting string is truncated.
2929  *
2930  * See the vsnprintf() documentation for format string extensions over C99.
2931  */
2932 int snprintf(char *buf, size_t size, const char *fmt, ...)
2933 {
2934         va_list args;
2935         int i;
2936
2937         va_start(args, fmt);
2938         i = vsnprintf(buf, size, fmt, args);
2939         va_end(args);
2940
2941         return i;
2942 }
2943 EXPORT_SYMBOL(snprintf);
2944
2945 /**
2946  * scnprintf - Format a string and place it in a buffer
2947  * @buf: The buffer to place the result into
2948  * @size: The size of the buffer, including the trailing null space
2949  * @fmt: The format string to use
2950  * @...: Arguments for the format string
2951  *
2952  * The return value is the number of characters written into @buf not including
2953  * the trailing '\0'. If @size is == 0 the function returns 0.
2954  */
2955
2956 int scnprintf(char *buf, size_t size, const char *fmt, ...)
2957 {
2958         va_list args;
2959         int i;
2960
2961         va_start(args, fmt);
2962         i = vscnprintf(buf, size, fmt, args);
2963         va_end(args);
2964
2965         return i;
2966 }
2967 EXPORT_SYMBOL(scnprintf);
2968
2969 /**
2970  * vsprintf - Format a string and place it in a buffer
2971  * @buf: The buffer to place the result into
2972  * @fmt: The format string to use
2973  * @args: Arguments for the format string
2974  *
2975  * The function returns the number of characters written
2976  * into @buf. Use vsnprintf() or vscnprintf() in order to avoid
2977  * buffer overflows.
2978  *
2979  * If you're not already dealing with a va_list consider using sprintf().
2980  *
2981  * See the vsnprintf() documentation for format string extensions over C99.
2982  */
2983 int vsprintf(char *buf, const char *fmt, va_list args)
2984 {
2985         return vsnprintf(buf, INT_MAX, fmt, args);
2986 }
2987 EXPORT_SYMBOL(vsprintf);
2988
2989 /**
2990  * sprintf - Format a string and place it in a buffer
2991  * @buf: The buffer to place the result into
2992  * @fmt: The format string to use
2993  * @...: Arguments for the format string
2994  *
2995  * The function returns the number of characters written
2996  * into @buf. Use snprintf() or scnprintf() in order to avoid
2997  * buffer overflows.
2998  *
2999  * See the vsnprintf() documentation for format string extensions over C99.
3000  */
3001 int sprintf(char *buf, const char *fmt, ...)
3002 {
3003         va_list args;
3004         int i;
3005
3006         va_start(args, fmt);
3007         i = vsnprintf(buf, INT_MAX, fmt, args);
3008         va_end(args);
3009
3010         return i;
3011 }
3012 EXPORT_SYMBOL(sprintf);
3013
3014 #ifdef CONFIG_BINARY_PRINTF
3015 /*
3016  * bprintf service:
3017  * vbin_printf() - VA arguments to binary data
3018  * bstr_printf() - Binary data to text string
3019  */
3020
3021 /**
3022  * vbin_printf - Parse a format string and place args' binary value in a buffer
3023  * @bin_buf: The buffer to place args' binary value
3024  * @size: The size of the buffer(by words(32bits), not characters)
3025  * @fmt: The format string to use
3026  * @args: Arguments for the format string
3027  *
3028  * The format follows C99 vsnprintf, except %n is ignored, and its argument
3029  * is skipped.
3030  *
3031  * The return value is the number of words(32bits) which would be generated for
3032  * the given input.
3033  *
3034  * NOTE:
3035  * If the return value is greater than @size, the resulting bin_buf is NOT
3036  * valid for bstr_printf().
3037  */
3038 int vbin_printf(u32 *bin_buf, size_t size, const char *fmt, va_list args)
3039 {
3040         struct printf_spec spec = {0};
3041         char *str, *end;
3042         int width;
3043
3044         str = (char *)bin_buf;
3045         end = (char *)(bin_buf + size);
3046
3047 #define save_arg(type)                                                  \
3048 ({                                                                      \
3049         unsigned long long value;                                       \
3050         if (sizeof(type) == 8) {                                        \
3051                 unsigned long long val8;                                \
3052                 str = PTR_ALIGN(str, sizeof(u32));                      \
3053                 val8 = va_arg(args, unsigned long long);                \
3054                 if (str + sizeof(type) <= end) {                        \
3055                         *(u32 *)str = *(u32 *)&val8;                    \
3056                         *(u32 *)(str + 4) = *((u32 *)&val8 + 1);        \
3057                 }                                                       \
3058                 value = val8;                                           \
3059         } else {                                                        \
3060                 unsigned int val4;                                      \
3061                 str = PTR_ALIGN(str, sizeof(type));                     \
3062                 val4 = va_arg(args, int);                               \
3063                 if (str + sizeof(type) <= end)                          \
3064                         *(typeof(type) *)str = (type)(long)val4;        \
3065                 value = (unsigned long long)val4;                       \
3066         }                                                               \
3067         str += sizeof(type);                                            \
3068         value;                                                          \
3069 })
3070
3071         while (*fmt) {
3072                 int read = format_decode(fmt, &spec);
3073
3074                 fmt += read;
3075
3076                 switch (spec.type) {
3077                 case FORMAT_TYPE_NONE:
3078                 case FORMAT_TYPE_PERCENT_CHAR:
3079                         break;
3080                 case FORMAT_TYPE_INVALID:
3081                         goto out;
3082
3083                 case FORMAT_TYPE_WIDTH:
3084                 case FORMAT_TYPE_PRECISION:
3085                         width = (int)save_arg(int);
3086                         /* Pointers may require the width */
3087                         if (*fmt == 'p')
3088                                 set_field_width(&spec, width);
3089                         break;
3090
3091                 case FORMAT_TYPE_CHAR:
3092                         save_arg(char);
3093                         break;
3094
3095                 case FORMAT_TYPE_STR: {
3096                         const char *save_str = va_arg(args, char *);
3097                         const char *err_msg;
3098                         size_t len;
3099
3100                         err_msg = check_pointer_msg(save_str);
3101                         if (err_msg)
3102                                 save_str = err_msg;
3103
3104                         len = strlen(save_str) + 1;
3105                         if (str + len < end)
3106                                 memcpy(str, save_str, len);
3107                         str += len;
3108                         break;
3109                 }
3110
3111                 case FORMAT_TYPE_PTR:
3112                         /* Dereferenced pointers must be done now */
3113                         switch (*fmt) {
3114                         /* Dereference of functions is still OK */
3115                         case 'S':
3116                         case 's':
3117                         case 'x':
3118                         case 'K':
3119                         case 'e':
3120                                 save_arg(void *);
3121                                 break;
3122                         default:
3123                                 if (!isalnum(*fmt)) {
3124                                         save_arg(void *);
3125                                         break;
3126                                 }
3127                                 str = pointer(fmt, str, end, va_arg(args, void *),
3128                                               spec);
3129                                 if (str + 1 < end)
3130                                         *str++ = '\0';
3131                                 else
3132                                         end[-1] = '\0'; /* Must be nul terminated */
3133                         }
3134                         /* skip all alphanumeric pointer suffixes */
3135                         while (isalnum(*fmt))
3136                                 fmt++;
3137                         break;
3138
3139                 default:
3140                         switch (spec.type) {
3141
3142                         case FORMAT_TYPE_LONG_LONG:
3143                                 save_arg(long long);
3144                                 break;
3145                         case FORMAT_TYPE_ULONG:
3146                         case FORMAT_TYPE_LONG:
3147                                 save_arg(unsigned long);
3148                                 break;
3149                         case FORMAT_TYPE_SIZE_T:
3150                                 save_arg(size_t);
3151                                 break;
3152                         case FORMAT_TYPE_PTRDIFF:
3153                                 save_arg(ptrdiff_t);
3154                                 break;
3155                         case FORMAT_TYPE_UBYTE:
3156                         case FORMAT_TYPE_BYTE:
3157                                 save_arg(char);
3158                                 break;
3159                         case FORMAT_TYPE_USHORT:
3160                         case FORMAT_TYPE_SHORT:
3161                                 save_arg(short);
3162                                 break;
3163                         default:
3164                                 save_arg(int);
3165                         }
3166                 }
3167         }
3168
3169 out:
3170         return (u32 *)(PTR_ALIGN(str, sizeof(u32))) - bin_buf;
3171 #undef save_arg
3172 }
3173 EXPORT_SYMBOL_GPL(vbin_printf);
3174
3175 /**
3176  * bstr_printf - Format a string from binary arguments and place it in a buffer
3177  * @buf: The buffer to place the result into
3178  * @size: The size of the buffer, including the trailing null space
3179  * @fmt: The format string to use
3180  * @bin_buf: Binary arguments for the format string
3181  *
3182  * This function like C99 vsnprintf, but the difference is that vsnprintf gets
3183  * arguments from stack, and bstr_printf gets arguments from @bin_buf which is
3184  * a binary buffer that generated by vbin_printf.
3185  *
3186  * The format follows C99 vsnprintf, but has some extensions:
3187  *  see vsnprintf comment for details.
3188  *
3189  * The return value is the number of characters which would
3190  * be generated for the given input, excluding the trailing
3191  * '\0', as per ISO C99. If you want to have the exact
3192  * number of characters written into @buf as return value
3193  * (not including the trailing '\0'), use vscnprintf(). If the
3194  * return is greater than or equal to @size, the resulting
3195  * string is truncated.
3196  */
3197 int bstr_printf(char *buf, size_t size, const char *fmt, const u32 *bin_buf)
3198 {
3199         struct printf_spec spec = {0};
3200         char *str, *end;
3201         const char *args = (const char *)bin_buf;
3202
3203         if (WARN_ON_ONCE(size > INT_MAX))
3204                 return 0;
3205
3206         str = buf;
3207         end = buf + size;
3208
3209 #define get_arg(type)                                                   \
3210 ({                                                                      \
3211         typeof(type) value;                                             \
3212         if (sizeof(type) == 8) {                                        \
3213                 args = PTR_ALIGN(args, sizeof(u32));                    \
3214                 *(u32 *)&value = *(u32 *)args;                          \
3215                 *((u32 *)&value + 1) = *(u32 *)(args + 4);              \
3216         } else {                                                        \
3217                 args = PTR_ALIGN(args, sizeof(type));                   \
3218                 value = *(typeof(type) *)args;                          \
3219         }                                                               \
3220         args += sizeof(type);                                           \
3221         value;                                                          \
3222 })
3223
3224         /* Make sure end is always >= buf */
3225         if (end < buf) {
3226                 end = ((void *)-1);
3227                 size = end - buf;
3228         }
3229
3230         while (*fmt) {
3231                 const char *old_fmt = fmt;
3232                 int read = format_decode(fmt, &spec);
3233
3234                 fmt += read;
3235
3236                 switch (spec.type) {
3237                 case FORMAT_TYPE_NONE: {
3238                         int copy = read;
3239                         if (str < end) {
3240                                 if (copy > end - str)
3241                                         copy = end - str;
3242                                 memcpy(str, old_fmt, copy);
3243                         }
3244                         str += read;
3245                         break;
3246                 }
3247
3248                 case FORMAT_TYPE_WIDTH:
3249                         set_field_width(&spec, get_arg(int));
3250                         break;
3251
3252                 case FORMAT_TYPE_PRECISION:
3253                         set_precision(&spec, get_arg(int));
3254                         break;
3255
3256                 case FORMAT_TYPE_CHAR: {
3257                         char c;
3258
3259                         if (!(spec.flags & LEFT)) {
3260                                 while (--spec.field_width > 0) {
3261                                         if (str < end)
3262                                                 *str = ' ';
3263                                         ++str;
3264                                 }
3265                         }
3266                         c = (unsigned char) get_arg(char);
3267                         if (str < end)
3268                                 *str = c;
3269                         ++str;
3270                         while (--spec.field_width > 0) {
3271                                 if (str < end)
3272                                         *str = ' ';
3273                                 ++str;
3274                         }
3275                         break;
3276                 }
3277
3278                 case FORMAT_TYPE_STR: {
3279                         const char *str_arg = args;
3280                         args += strlen(str_arg) + 1;
3281                         str = string(str, end, (char *)str_arg, spec);
3282                         break;
3283                 }
3284
3285                 case FORMAT_TYPE_PTR: {
3286                         bool process = false;
3287                         int copy, len;
3288                         /* Non function dereferences were already done */
3289                         switch (*fmt) {
3290                         case 'S':
3291                         case 's':
3292                         case 'x':
3293                         case 'K':
3294                         case 'e':
3295                                 process = true;
3296                                 break;
3297                         default:
3298                                 if (!isalnum(*fmt)) {
3299                                         process = true;
3300                                         break;
3301                                 }
3302                                 /* Pointer dereference was already processed */
3303                                 if (str < end) {
3304                                         len = copy = strlen(args);
3305                                         if (copy > end - str)
3306                                                 copy = end - str;
3307                                         memcpy(str, args, copy);
3308                                         str += len;
3309                                         args += len + 1;
3310                                 }
3311                         }
3312                         if (process)
3313                                 str = pointer(fmt, str, end, get_arg(void *), spec);
3314
3315                         while (isalnum(*fmt))
3316                                 fmt++;
3317                         break;
3318                 }
3319
3320                 case FORMAT_TYPE_PERCENT_CHAR:
3321                         if (str < end)
3322                                 *str = '%';
3323                         ++str;
3324                         break;
3325
3326                 case FORMAT_TYPE_INVALID:
3327                         goto out;
3328
3329                 default: {
3330                         unsigned long long num;
3331
3332                         switch (spec.type) {
3333
3334                         case FORMAT_TYPE_LONG_LONG:
3335                                 num = get_arg(long long);
3336                                 break;
3337                         case FORMAT_TYPE_ULONG:
3338                         case FORMAT_TYPE_LONG:
3339                                 num = get_arg(unsigned long);
3340                                 break;
3341                         case FORMAT_TYPE_SIZE_T:
3342                                 num = get_arg(size_t);
3343                                 break;
3344                         case FORMAT_TYPE_PTRDIFF:
3345                                 num = get_arg(ptrdiff_t);
3346                                 break;
3347                         case FORMAT_TYPE_UBYTE:
3348                                 num = get_arg(unsigned char);
3349                                 break;
3350                         case FORMAT_TYPE_BYTE:
3351                                 num = get_arg(signed char);
3352                                 break;
3353                         case FORMAT_TYPE_USHORT:
3354                                 num = get_arg(unsigned short);
3355                                 break;
3356                         case FORMAT_TYPE_SHORT:
3357                                 num = get_arg(short);
3358                                 break;
3359                         case FORMAT_TYPE_UINT:
3360                                 num = get_arg(unsigned int);
3361                                 break;
3362                         default:
3363                                 num = get_arg(int);
3364                         }
3365
3366                         str = number(str, end, num, spec);
3367                 } /* default: */
3368                 } /* switch(spec.type) */
3369         } /* while(*fmt) */
3370
3371 out:
3372         if (size > 0) {
3373                 if (str < end)
3374                         *str = '\0';
3375                 else
3376                         end[-1] = '\0';
3377         }
3378
3379 #undef get_arg
3380
3381         /* the trailing null byte doesn't count towards the total */
3382         return str - buf;
3383 }
3384 EXPORT_SYMBOL_GPL(bstr_printf);
3385
3386 /**
3387  * bprintf - Parse a format string and place args' binary value in a buffer
3388  * @bin_buf: The buffer to place args' binary value
3389  * @size: The size of the buffer(by words(32bits), not characters)
3390  * @fmt: The format string to use
3391  * @...: Arguments for the format string
3392  *
3393  * The function returns the number of words(u32) written
3394  * into @bin_buf.
3395  */
3396 int bprintf(u32 *bin_buf, size_t size, const char *fmt, ...)
3397 {
3398         va_list args;
3399         int ret;
3400
3401         va_start(args, fmt);
3402         ret = vbin_printf(bin_buf, size, fmt, args);
3403         va_end(args);
3404
3405         return ret;
3406 }
3407 EXPORT_SYMBOL_GPL(bprintf);
3408
3409 #endif /* CONFIG_BINARY_PRINTF */
3410
3411 /**
3412  * vsscanf - Unformat a buffer into a list of arguments
3413  * @buf:        input buffer
3414  * @fmt:        format of buffer
3415  * @args:       arguments
3416  */
3417 int vsscanf(const char *buf, const char *fmt, va_list args)
3418 {
3419         const char *str = buf;
3420         char *next;
3421         char digit;
3422         int num = 0;
3423         u8 qualifier;
3424         unsigned int base;
3425         union {
3426                 long long s;
3427                 unsigned long long u;
3428         } val;
3429         s16 field_width;
3430         bool is_sign;
3431
3432         while (*fmt) {
3433                 /* skip any white space in format */
3434                 /* white space in format matches any amount of
3435                  * white space, including none, in the input.
3436                  */
3437                 if (isspace(*fmt)) {
3438                         fmt = skip_spaces(++fmt);
3439                         str = skip_spaces(str);
3440                 }
3441
3442                 /* anything that is not a conversion must match exactly */
3443                 if (*fmt != '%' && *fmt) {
3444                         if (*fmt++ != *str++)
3445                                 break;
3446                         continue;
3447                 }
3448
3449                 if (!*fmt)
3450                         break;
3451                 ++fmt;
3452
3453                 /* skip this conversion.
3454                  * advance both strings to next white space
3455                  */
3456                 if (*fmt == '*') {
3457                         if (!*str)
3458                                 break;
3459                         while (!isspace(*fmt) && *fmt != '%' && *fmt) {
3460                                 /* '%*[' not yet supported, invalid format */
3461                                 if (*fmt == '[')
3462                                         return num;
3463                                 fmt++;
3464                         }
3465                         while (!isspace(*str) && *str)
3466                                 str++;
3467                         continue;
3468                 }
3469
3470                 /* get field width */
3471                 field_width = -1;
3472                 if (isdigit(*fmt)) {
3473                         field_width = skip_atoi(&fmt);
3474                         if (field_width <= 0)
3475                                 break;
3476                 }
3477
3478                 /* get conversion qualifier */
3479                 qualifier = -1;
3480                 if (*fmt == 'h' || _tolower(*fmt) == 'l' ||
3481                     *fmt == 'z') {
3482                         qualifier = *fmt++;
3483                         if (unlikely(qualifier == *fmt)) {
3484                                 if (qualifier == 'h') {
3485                                         qualifier = 'H';
3486                                         fmt++;
3487                                 } else if (qualifier == 'l') {
3488                                         qualifier = 'L';
3489                                         fmt++;
3490                                 }
3491                         }
3492                 }
3493
3494                 if (!*fmt)
3495                         break;
3496
3497                 if (*fmt == 'n') {
3498                         /* return number of characters read so far */
3499                         *va_arg(args, int *) = str - buf;
3500                         ++fmt;
3501                         continue;
3502                 }
3503
3504                 if (!*str)
3505                         break;
3506
3507                 base = 10;
3508                 is_sign = false;
3509
3510                 switch (*fmt++) {
3511                 case 'c':
3512                 {
3513                         char *s = (char *)va_arg(args, char*);
3514                         if (field_width == -1)
3515                                 field_width = 1;
3516                         do {
3517                                 *s++ = *str++;
3518                         } while (--field_width > 0 && *str);
3519                         num++;
3520                 }
3521                 continue;
3522                 case 's':
3523                 {
3524                         char *s = (char *)va_arg(args, char *);
3525                         if (field_width == -1)
3526                                 field_width = SHRT_MAX;
3527                         /* first, skip leading white space in buffer */
3528                         str = skip_spaces(str);
3529
3530                         /* now copy until next white space */
3531                         while (*str && !isspace(*str) && field_width--)
3532                                 *s++ = *str++;
3533                         *s = '\0';
3534                         num++;
3535                 }
3536                 continue;
3537                 /*
3538                  * Warning: This implementation of the '[' conversion specifier
3539                  * deviates from its glibc counterpart in the following ways:
3540                  * (1) It does NOT support ranges i.e. '-' is NOT a special
3541                  *     character
3542                  * (2) It cannot match the closing bracket ']' itself
3543                  * (3) A field width is required
3544                  * (4) '%*[' (discard matching input) is currently not supported
3545                  *
3546                  * Example usage:
3547                  * ret = sscanf("00:0a:95","%2[^:]:%2[^:]:%2[^:]",
3548                  *              buf1, buf2, buf3);
3549                  * if (ret < 3)
3550                  *    // etc..
3551                  */
3552                 case '[':
3553                 {
3554                         char *s = (char *)va_arg(args, char *);
3555                         DECLARE_BITMAP(set, 256) = {0};
3556                         unsigned int len = 0;
3557                         bool negate = (*fmt == '^');
3558
3559                         /* field width is required */
3560                         if (field_width == -1)
3561                                 return num;
3562
3563                         if (negate)
3564                                 ++fmt;
3565
3566                         for ( ; *fmt && *fmt != ']'; ++fmt, ++len)
3567                                 __set_bit((u8)*fmt, set);
3568
3569                         /* no ']' or no character set found */
3570                         if (!*fmt || !len)
3571                                 return num;
3572                         ++fmt;
3573
3574                         if (negate) {
3575                                 bitmap_complement(set, set, 256);
3576                                 /* exclude null '\0' byte */
3577                                 __clear_bit(0, set);
3578                         }
3579
3580                         /* match must be non-empty */
3581                         if (!test_bit((u8)*str, set))
3582                                 return num;
3583
3584                         while (test_bit((u8)*str, set) && field_width--)
3585                                 *s++ = *str++;
3586                         *s = '\0';
3587                         ++num;
3588                 }
3589                 continue;
3590                 case 'o':
3591                         base = 8;
3592                         break;
3593                 case 'x':
3594                 case 'X':
3595                         base = 16;
3596                         break;
3597                 case 'i':
3598                         base = 0;
3599                         fallthrough;
3600                 case 'd':
3601                         is_sign = true;
3602                         fallthrough;
3603                 case 'u':
3604                         break;
3605                 case '%':
3606                         /* looking for '%' in str */
3607                         if (*str++ != '%')
3608                                 return num;
3609                         continue;
3610                 default:
3611                         /* invalid format; stop here */
3612                         return num;
3613                 }
3614
3615                 /* have some sort of integer conversion.
3616                  * first, skip white space in buffer.
3617                  */
3618                 str = skip_spaces(str);
3619
3620                 digit = *str;
3621                 if (is_sign && digit == '-') {
3622                         if (field_width == 1)
3623                                 break;
3624
3625                         digit = *(str + 1);
3626                 }
3627
3628                 if (!digit
3629                     || (base == 16 && !isxdigit(digit))
3630                     || (base == 10 && !isdigit(digit))
3631                     || (base == 8 && !isodigit(digit))
3632                     || (base == 0 && !isdigit(digit)))
3633                         break;
3634
3635                 if (is_sign)
3636                         val.s = simple_strntoll(str, &next, base,
3637                                                 field_width >= 0 ? field_width : INT_MAX);
3638                 else
3639                         val.u = simple_strntoull(str, &next, base,
3640                                                  field_width >= 0 ? field_width : INT_MAX);
3641
3642                 switch (qualifier) {
3643                 case 'H':       /* that's 'hh' in format */
3644                         if (is_sign)
3645                                 *va_arg(args, signed char *) = val.s;
3646                         else
3647                                 *va_arg(args, unsigned char *) = val.u;
3648                         break;
3649                 case 'h':
3650                         if (is_sign)
3651                                 *va_arg(args, short *) = val.s;
3652                         else
3653                                 *va_arg(args, unsigned short *) = val.u;
3654                         break;
3655                 case 'l':
3656                         if (is_sign)
3657                                 *va_arg(args, long *) = val.s;
3658                         else
3659                                 *va_arg(args, unsigned long *) = val.u;
3660                         break;
3661                 case 'L':
3662                         if (is_sign)
3663                                 *va_arg(args, long long *) = val.s;
3664                         else
3665                                 *va_arg(args, unsigned long long *) = val.u;
3666                         break;
3667                 case 'z':
3668                         *va_arg(args, size_t *) = val.u;
3669                         break;
3670                 default:
3671                         if (is_sign)
3672                                 *va_arg(args, int *) = val.s;
3673                         else
3674                                 *va_arg(args, unsigned int *) = val.u;
3675                         break;
3676                 }
3677                 num++;
3678
3679                 if (!next)
3680                         break;
3681                 str = next;
3682         }
3683
3684         return num;
3685 }
3686 EXPORT_SYMBOL(vsscanf);
3687
3688 /**
3689  * sscanf - Unformat a buffer into a list of arguments
3690  * @buf:        input buffer
3691  * @fmt:        formatting of buffer
3692  * @...:        resulting arguments
3693  */
3694 int sscanf(const char *buf, const char *fmt, ...)
3695 {
3696         va_list args;
3697         int i;
3698
3699         va_start(args, fmt);
3700         i = vsscanf(buf, fmt, args);
3701         va_end(args);
3702
3703         return i;
3704 }
3705 EXPORT_SYMBOL(sscanf);