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 <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/time.h>
  38 #include <linux/uuid.h>
  39 #include <linux/of.h>
  40 #include <net/addrconf.h>
  41 #include <linux/siphash.h>
  42 #include <linux/compiler.h>
  43 #include <linux/property.h>
  44 #ifdef CONFIG_BLOCK
  45 #include <linux/blkdev.h>
  46 #endif
  47
  48 #include "../mm/internal.h"     /* For the trace_print_flags arrays */
  49
  50 #include <asm/page.h>           /* for PAGE_SIZE */
  51 #include <asm/byteorder.h>      /* cpu_to_le16 */
  52
  53 #include <linux/string_helpers.h>
  54 #include "kstrtox.h"
  55
  56 /**
  57  * simple_strtoull - convert a string to an unsigned long long
  58  * @cp: The start of the string
  59  * @endp: A pointer to the end of the parsed string will be placed here
  60  * @base: The number base to use
  61  *
  62  * This function has caveats. Please use kstrtoull instead.
  63  */
  64 unsigned long long simple_strtoull(const char *cp, char **endp, unsigned int base)
  65 {
  66         unsigned long long result;
  67         unsigned int rv;
  68
  69         cp = _parse_integer_fixup_radix(cp, &base);
  70         rv = _parse_integer(cp, base, &result);
  71         /* FIXME */
  72         cp += (rv & ~KSTRTOX_OVERFLOW);
  73
  74         if (endp)
  75                 *endp = (char *)cp;
  76
  77         return result;
  78 }
  79 EXPORT_SYMBOL(simple_strtoull);
  80
  81 /**
  82  * simple_strtoul - convert a string to an unsigned long
  83  * @cp: The start of the string
  84  * @endp: A pointer to the end of the parsed string will be placed here
  85  * @base: The number base to use
  86  *
  87  * This function has caveats. Please use kstrtoul instead.
  88  */
  89 unsigned long simple_strtoul(const char *cp, char **endp, unsigned int base)
  90 {
  91         return simple_strtoull(cp, endp, base);
  92 }
  93 EXPORT_SYMBOL(simple_strtoul);
  94
  95 /**
  96  * simple_strtol - convert a string to a signed long
  97  * @cp: The start of the string
  98  * @endp: A pointer to the end of the parsed string will be placed here
  99  * @base: The number base to use
 100  *
 101  * This function has caveats. Please use kstrtol instead.
 102  */
 103 long simple_strtol(const char *cp, char **endp, unsigned int base)
 104 {
 105         if (*cp == '-')
 106                 return -simple_strtoul(cp + 1, endp, base);
 107
 108         return simple_strtoul(cp, endp, base);
 109 }
 110 EXPORT_SYMBOL(simple_strtol);
 111
 112 /**
 113  * simple_strtoll - convert a string to a signed long long
 114  * @cp: The start of the string
 115  * @endp: A pointer to the end of the parsed string will be placed here
 116  * @base: The number base to use
 117  *
 118  * This function has caveats. Please use kstrtoll instead.
 119  */
 120 long long simple_strtoll(const char *cp, char **endp, unsigned int base)
 121 {
 122         if (*cp == '-')
 123                 return -simple_strtoull(cp + 1, endp, base);
 124
 125         return simple_strtoull(cp, endp, base);
 126 }
 127 EXPORT_SYMBOL(simple_strtoll);
 128
 129 static noinline_for_stack
 130 int skip_atoi(const char **s)
 131 {
 132         int i = 0;
 133
 134         do {
 135                 i = i*10 + *((*s)++) - '0';
 136         } while (isdigit(**s));
 137
 138         return i;
 139 }
 140
 141 /*
 142  * Decimal conversion is by far the most typical, and is used for
 143  * /proc and /sys data. This directly impacts e.g. top performance
 144  * with many processes running. We optimize it for speed by emitting
 145  * two characters at a time, using a 200 byte lookup table. This
 146  * roughly halves the number of multiplications compared to computing
 147  * the digits one at a time. Implementation strongly inspired by the
 148  * previous version, which in turn used ideas described at
 149  * <http://www.cs.uiowa.edu/~jones/bcd/divide.html> (with permission
 150  * from the author, Douglas W. Jones).
 151  *
 152  * It turns out there is precisely one 26 bit fixed-point
 153  * approximation a of 64/100 for which x/100 == (x * (u64)a) >> 32
 154  * holds for all x in [0, 10^8-1], namely a = 0x28f5c29. The actual
 155  * range happens to be somewhat larger (x <= 1073741898), but that's
 156  * irrelevant for our purpose.
 157  *
 158  * For dividing a number in the range [10^4, 10^6-1] by 100, we still
 159  * need a 32x32->64 bit multiply, so we simply use the same constant.
 160  *
 161  * For dividing a number in the range [100, 10^4-1] by 100, there are
 162  * several options. The simplest is (x * 0x147b) >> 19, which is valid
 163  * for all x <= 43698.
 164  */
 165
 166 static const u16 decpair[100] = {
 167 #define _(x) (__force u16) cpu_to_le16(((x % 10) | ((x / 10) << 8)) + 0x3030)
 168         _( 0), _( 1), _( 2), _( 3), _( 4), _( 5), _( 6), _( 7), _( 8), _( 9),
 169         _(10), _(11), _(12), _(13), _(14), _(15), _(16), _(17), _(18), _(19),
 170         _(20), _(21), _(22), _(23), _(24), _(25), _(26), _(27), _(28), _(29),
 171         _(30), _(31), _(32), _(33), _(34), _(35), _(36), _(37), _(38), _(39),
 172         _(40), _(41), _(42), _(43), _(44), _(45), _(46), _(47), _(48), _(49),
 173         _(50), _(51), _(52), _(53), _(54), _(55), _(56), _(57), _(58), _(59),
 174         _(60), _(61), _(62), _(63), _(64), _(65), _(66), _(67), _(68), _(69),
 175         _(70), _(71), _(72), _(73), _(74), _(75), _(76), _(77), _(78), _(79),
 176         _(80), _(81), _(82), _(83), _(84), _(85), _(86), _(87), _(88), _(89),
 177         _(90), _(91), _(92), _(93), _(94), _(95), _(96), _(97), _(98), _(99),
 178 #undef _
 179 };
 180
 181 /*
 182  * This will print a single '0' even if r == 0, since we would
 183  * immediately jump to out_r where two 0s would be written but only
 184  * one of them accounted for in buf. This is needed by ip4_string
 185  * below. All other callers pass a non-zero value of r.
 186 */
 187 static noinline_for_stack
 188 char *put_dec_trunc8(char *buf, unsigned r)
 189 {
 190         unsigned q;
 191
 192         /* 1 <= r < 10^8 */
 193         if (r < 100)
 194                 goto out_r;
 195
 196         /* 100 <= r < 10^8 */
 197         q = (r * (u64)0x28f5c29) >> 32;
 198         *((u16 *)buf) = decpair[r - 100*q];
 199         buf += 2;
 200
 201         /* 1 <= q < 10^6 */
 202         if (q < 100)
 203                 goto out_q;
 204
 205         /*  100 <= q < 10^6 */
 206         r = (q * (u64)0x28f5c29) >> 32;
 207         *((u16 *)buf) = decpair[q - 100*r];
 208         buf += 2;
 209
 210         /* 1 <= r < 10^4 */
 211         if (r < 100)
 212                 goto out_r;
 213
 214         /* 100 <= r < 10^4 */
 215         q = (r * 0x147b) >> 19;
 216         *((u16 *)buf) = decpair[r - 100*q];
 217         buf += 2;
 218 out_q:
 219         /* 1 <= q < 100 */
 220         r = q;
 221 out_r:
 222         /* 1 <= r < 100 */
 223         *((u16 *)buf) = decpair[r];
 224         buf += r < 10 ? 1 : 2;
 225         return buf;
 226 }
 227
 228 #if BITS_PER_LONG == 64 && BITS_PER_LONG_LONG == 64
 229 static noinline_for_stack
 230 char *put_dec_full8(char *buf, unsigned r)
 231 {
 232         unsigned q;
 233
 234         /* 0 <= r < 10^8 */
 235         q = (r * (u64)0x28f5c29) >> 32;
 236         *((u16 *)buf) = decpair[r - 100*q];
 237         buf += 2;
 238
 239         /* 0 <= q < 10^6 */
 240         r = (q * (u64)0x28f5c29) >> 32;
 241         *((u16 *)buf) = decpair[q - 100*r];
 242         buf += 2;
 243
 244         /* 0 <= r < 10^4 */
 245         q = (r * 0x147b) >> 19;
 246         *((u16 *)buf) = decpair[r - 100*q];
 247         buf += 2;
 248
 249         /* 0 <= q < 100 */
 250         *((u16 *)buf) = decpair[q];
 251         buf += 2;
 252         return buf;
 253 }
 254
 255 static noinline_for_stack
 256 char *put_dec(char *buf, unsigned long long n)
 257 {
 258         if (n >= 100*1000*1000)
 259                 buf = put_dec_full8(buf, do_div(n, 100*1000*1000));
 260         /* 1 <= n <= 1.6e11 */
 261         if (n >= 100*1000*1000)
 262                 buf = put_dec_full8(buf, do_div(n, 100*1000*1000));
 263         /* 1 <= n < 1e8 */
 264         return put_dec_trunc8(buf, n);
 265 }
 266
 267 #elif BITS_PER_LONG == 32 && BITS_PER_LONG_LONG == 64
 268
 269 static void
 270 put_dec_full4(char *buf, unsigned r)
 271 {
 272         unsigned q;
 273
 274         /* 0 <= r < 10^4 */
 275         q = (r * 0x147b) >> 19;
 276         *((u16 *)buf) = decpair[r - 100*q];
 277         buf += 2;
 278         /* 0 <= q < 100 */
 279         *((u16 *)buf) = decpair[q];
 280 }
 281
 282 /*
 283  * Call put_dec_full4 on x % 10000, return x / 10000.
 284  * The approximation x/10000 == (x * 0x346DC5D7) >> 43
 285  * holds for all x < 1,128,869,999.  The largest value this
 286  * helper will ever be asked to convert is 1,125,520,955.
 287  * (second call in the put_dec code, assuming n is all-ones).
 288  */
 289 static noinline_for_stack
 290 unsigned put_dec_helper4(char *buf, unsigned x)
 291 {
 292         uint32_t q = (x * (uint64_t)0x346DC5D7) >> 43;
 293
 294         put_dec_full4(buf, x - q * 10000);
 295         return q;
 296 }
 297
 298 /* Based on code by Douglas W. Jones found at
 299  * <http://www.cs.uiowa.edu/~jones/bcd/decimal.html#sixtyfour>
 300  * (with permission from the author).
 301  * Performs no 64-bit division and hence should be fast on 32-bit machines.
 302  */
 303 static
 304 char *put_dec(char *buf, unsigned long long n)
 305 {
 306         uint32_t d3, d2, d1, q, h;
 307
 308         if (n < 100*1000*1000)
 309                 return put_dec_trunc8(buf, n);
 310
 311         d1  = ((uint32_t)n >> 16); /* implicit "& 0xffff" */
 312         h   = (n >> 32);
 313         d2  = (h      ) & 0xffff;
 314         d3  = (h >> 16); /* implicit "& 0xffff" */
 315
 316         /* n = 2^48 d3 + 2^32 d2 + 2^16 d1 + d0
 317              = 281_4749_7671_0656 d3 + 42_9496_7296 d2 + 6_5536 d1 + d0 */
 318         q   = 656 * d3 + 7296 * d2 + 5536 * d1 + ((uint32_t)n & 0xffff);
 319         q = put_dec_helper4(buf, q);
 320
 321         q += 7671 * d3 + 9496 * d2 + 6 * d1;
 322         q = put_dec_helper4(buf+4, q);
 323
 324         q += 4749 * d3 + 42 * d2;
 325         q = put_dec_helper4(buf+8, q);
 326
 327         q += 281 * d3;
 328         buf += 12;
 329         if (q)
 330                 buf = put_dec_trunc8(buf, q);
 331         else while (buf[-1] == '0')
 332                 --buf;
 333
 334         return buf;
 335 }
 336
 337 #endif
 338
 339 /*
 340  * Convert passed number to decimal string.
 341  * Returns the length of string.  On buffer overflow, returns 0.
 342  *
 343  * If speed is not important, use snprintf(). It's easy to read the code.
 344  */
 345 int num_to_str(char *buf, int size, unsigned long long num, unsigned int width)
 346 {
 347         /* put_dec requires 2-byte alignment of the buffer. */
 348         char tmp[sizeof(num) * 3] __aligned(2);
 349         int idx, len;
 350
 351         /* put_dec() may work incorrectly for num = 0 (generate "", not "0") */
 352         if (num <= 9) {
 353                 tmp[0] = '0' + num;
 354                 len = 1;
 355         } else {
 356                 len = put_dec(tmp, num) - tmp;
 357         }
 358
 359         if (len > size || width > size)
 360                 return 0;
 361
 362         if (width > len) {
 363                 width = width - len;
 364                 for (idx = 0; idx < width; idx++)
 365                         buf[idx] = ' ';
 366         } else {
 367                 width = 0;
 368         }
 369
 370         for (idx = 0; idx < len; ++idx)
 371                 buf[idx + width] = tmp[len - idx - 1];
 372
 373         return len + width;
 374 }
 375
 376 #define SIGN    1               /* unsigned/signed, must be 1 */
 377 #define LEFT    2               /* left justified */
 378 #define PLUS    4               /* show plus */
 379 #define SPACE   8               /* space if plus */
 380 #define ZEROPAD 16              /* pad with zero, must be 16 == '0' - ' ' */
 381 #define SMALL   32              /* use lowercase in hex (must be 32 == 0x20) */
 382 #define SPECIAL 64              /* prefix hex with "0x", octal with "0" */
 383
 384 static_assert(ZEROPAD == ('0' - ' '));
 385 static_assert(SMALL == ' ');
 386
 387 enum format_type {
 388         FORMAT_TYPE_NONE, /* Just a string part */
 389         FORMAT_TYPE_WIDTH,
 390         FORMAT_TYPE_PRECISION,
 391         FORMAT_TYPE_CHAR,
 392         FORMAT_TYPE_STR,
 393         FORMAT_TYPE_PTR,
 394         FORMAT_TYPE_PERCENT_CHAR,
 395         FORMAT_TYPE_INVALID,
 396         FORMAT_TYPE_LONG_LONG,
 397         FORMAT_TYPE_ULONG,
 398         FORMAT_TYPE_LONG,
 399         FORMAT_TYPE_UBYTE,
 400         FORMAT_TYPE_BYTE,
 401         FORMAT_TYPE_USHORT,
 402         FORMAT_TYPE_SHORT,
 403         FORMAT_TYPE_UINT,
 404         FORMAT_TYPE_INT,
 405         FORMAT_TYPE_SIZE_T,
 406         FORMAT_TYPE_PTRDIFF
 407 };
 408
 409 struct printf_spec {
 410         unsigned int    type:8;         /* format_type enum */
 411         signed int      field_width:24; /* width of output field */
 412         unsigned int    flags:8;        /* flags to number() */
 413         unsigned int    base:8;         /* number base, 8, 10 or 16 only */
 414         signed int      precision:16;   /* # of digits/chars */
 415 } __packed;
 416 static_assert(sizeof(struct printf_spec) == 8);
 417
 418 #define FIELD_WIDTH_MAX ((1 << 23) - 1)
 419 #define PRECISION_MAX ((1 << 15) - 1)
 420
 421 static noinline_for_stack
 422 char *number(char *buf, char *end, unsigned long long num,
 423              struct printf_spec spec)
 424 {
 425         /* put_dec requires 2-byte alignment of the buffer. */
 426         char tmp[3 * sizeof(num)] __aligned(2);
 427         char sign;
 428         char locase;
 429         int need_pfx = ((spec.flags & SPECIAL) && spec.base != 10);
 430         int i;
 431         bool is_zero = num == 0LL;
 432         int field_width = spec.field_width;
 433         int precision = spec.precision;
 434
 435         /* locase = 0 or 0x20. ORing digits or letters with 'locase'
 436          * produces same digits or (maybe lowercased) letters */
 437         locase = (spec.flags & SMALL);
 438         if (spec.flags & LEFT)
 439                 spec.flags &= ~ZEROPAD;
 440         sign = 0;
 441         if (spec.flags & SIGN) {
 442                 if ((signed long long)num < 0) {
 443                         sign = '-';
 444                         num = -(signed long long)num;
 445                         field_width--;
 446                 } else if (spec.flags & PLUS) {
 447                         sign = '+';
 448                         field_width--;
 449                 } else if (spec.flags & SPACE) {
 450                         sign = ' ';
 451                         field_width--;
 452                 }
 453         }
 454         if (need_pfx) {
 455                 if (spec.base == 16)
 456                         field_width -= 2;
 457                 else if (!is_zero)
 458                         field_width--;
 459         }
 460
 461         /* generate full string in tmp[], in reverse order */
 462         i = 0;
 463         if (num < spec.base)
 464                 tmp[i++] = hex_asc_upper[num] | locase;
 465         else if (spec.base != 10) { /* 8 or 16 */
 466                 int mask = spec.base - 1;
 467                 int shift = 3;
 468
 469                 if (spec.base == 16)
 470                         shift = 4;
 471                 do {
 472                         tmp[i++] = (hex_asc_upper[((unsigned char)num) & mask] | locase);
 473                         num >>= shift;
 474                 } while (num);
 475         } else { /* base 10 */
 476                 i = put_dec(tmp, num) - tmp;
 477         }
 478
 479         /* printing 100 using %2d gives "100", not "00" */
 480         if (i > precision)
 481                 precision = i;
 482         /* leading space padding */
 483         field_width -= precision;
 484         if (!(spec.flags & (ZEROPAD | LEFT))) {
 485                 while (--field_width >= 0) {
 486                         if (buf < end)
 487                                 *buf = ' ';
 488                         ++buf;
 489                 }
 490         }
 491         /* sign */
 492         if (sign) {
 493                 if (buf < end)
 494                         *buf = sign;
 495                 ++buf;
 496         }
 497         /* "0x" / "0" prefix */
 498         if (need_pfx) {
 499                 if (spec.base == 16 || !is_zero) {
 500                         if (buf < end)
 501                                 *buf = '0';
 502                         ++buf;
 503                 }
 504                 if (spec.base == 16) {
 505                         if (buf < end)
 506                                 *buf = ('X' | locase);
 507                         ++buf;
 508                 }
 509         }
 510         /* zero or space padding */
 511         if (!(spec.flags & LEFT)) {
 512                 char c = ' ' + (spec.flags & ZEROPAD);
 513
 514                 while (--field_width >= 0) {
 515                         if (buf < end)
 516                                 *buf = c;
 517                         ++buf;
 518                 }
 519         }
 520         /* hmm even more zero padding? */
 521         while (i <= --precision) {
 522                 if (buf < end)
 523                         *buf = '0';
 524                 ++buf;
 525         }
 526         /* actual digits of result */
 527         while (--i >= 0) {
 528                 if (buf < end)
 529                         *buf = tmp[i];
 530                 ++buf;
 531         }
 532         /* trailing space padding */
 533         while (--field_width >= 0) {
 534                 if (buf < end)
 535                         *buf = ' ';
 536                 ++buf;
 537         }
 538
 539         return buf;
 540 }
 541
 542 static noinline_for_stack
 543 char *special_hex_number(char *buf, char *end, unsigned long long num, int size)
 544 {
 545         struct printf_spec spec;
 546
 547         spec.type = FORMAT_TYPE_PTR;
 548         spec.field_width = 2 + 2 * size;        /* 0x + hex */
 549         spec.flags = SPECIAL | SMALL | ZEROPAD;
 550         spec.base = 16;
 551         spec.precision = -1;
 552
 553         return number(buf, end, num, spec);
 554 }
 555
 556 static void move_right(char *buf, char *end, unsigned len, unsigned spaces)
 557 {
 558         size_t size;
 559         if (buf >= end) /* nowhere to put anything */
 560                 return;
 561         size = end - buf;
 562         if (size <= spaces) {
 563                 memset(buf, ' ', size);
 564                 return;
 565         }
 566         if (len) {
 567                 if (len > size - spaces)
 568                         len = size - spaces;
 569                 memmove(buf + spaces, buf, len);
 570         }
 571         memset(buf, ' ', spaces);
 572 }
 573
 574 /*
 575  * Handle field width padding for a string.
 576  * @buf: current buffer position
 577  * @n: length of string
 578  * @end: end of output buffer
 579  * @spec: for field width and flags
 580  * Returns: new buffer position after padding.
 581  */
 582 static noinline_for_stack
 583 char *widen_string(char *buf, int n, char *end, struct printf_spec spec)
 584 {
 585         unsigned spaces;
 586
 587         if (likely(n >= spec.field_width))
 588                 return buf;
 589         /* we want to pad the sucker */
 590         spaces = spec.field_width - n;
 591         if (!(spec.flags & LEFT)) {
 592                 move_right(buf - n, end, n, spaces);
 593                 return buf + spaces;
 594         }
 595         while (spaces--) {
 596                 if (buf < end)
 597                         *buf = ' ';
 598                 ++buf;
 599         }
 600         return buf;
 601 }
 602
 603 /* Handle string from a well known address. */
 604 static char *string_nocheck(char *buf, char *end, const char *s,
 605                             struct printf_spec spec)
 606 {
 607         int len = 0;
 608         int lim = spec.precision;
 609
 610         while (lim--) {
 611                 char c = *s++;
 612                 if (!c)
 613                         break;
 614                 if (buf < end)
 615                         *buf = c;
 616                 ++buf;
 617                 ++len;
 618         }
 619         return widen_string(buf, len, end, spec);
 620 }
 621
 622 static char *err_ptr(char *buf, char *end, void *ptr,
 623                      struct printf_spec spec)
 624 {
 625         int err = PTR_ERR(ptr);
 626         const char *sym = errname(err);
 627
 628         if (sym)
 629                 return string_nocheck(buf, end, sym, spec);
 630
 631         /*
 632          * Somebody passed ERR_PTR(-1234) or some other non-existing
 633          * Efoo - or perhaps CONFIG_SYMBOLIC_ERRNAME=n. Fall back to
 634          * printing it as its decimal representation.
 635          */
 636         spec.flags |= SIGN;
 637         spec.base = 10;
 638         return number(buf, end, err, spec);
 639 }
 640
 641 /* Be careful: error messages must fit into the given buffer. */
 642 static char *error_string(char *buf, char *end, const char *s,
 643                           struct printf_spec spec)
 644 {
 645         /*
 646          * Hard limit to avoid a completely insane messages. It actually
 647          * works pretty well because most error messages are in
 648          * the many pointer format modifiers.
 649          */
 650         if (spec.precision == -1)
 651                 spec.precision = 2 * sizeof(void *);
 652
 653         return string_nocheck(buf, end, s, spec);
 654 }
 655
 656 /*
 657  * Do not call any complex external code here. Nested printk()/vsprintf()
 658  * might cause infinite loops. Failures might break printk() and would
 659  * be hard to debug.
 660  */
 661 static const char *check_pointer_msg(const void *ptr)
 662 {
 663         if (!ptr)
 664                 return "(null)";
 665
 666         if ((unsigned long)ptr < PAGE_SIZE || IS_ERR_VALUE(ptr))
 667                 return "(efault)";
 668
 669         return NULL;
 670 }
 671
 672 static int check_pointer(char **buf, char *end, const void *ptr,
 673                          struct printf_spec spec)
 674 {
 675         const char *err_msg;
 676
 677         err_msg = check_pointer_msg(ptr);
 678         if (err_msg) {
 679                 *buf = error_string(*buf, end, err_msg, spec);
 680                 return -EFAULT;
 681         }
 682
 683         return 0;
 684 }
 685
 686 static noinline_for_stack
 687 char *string(char *buf, char *end, const char *s,
 688              struct printf_spec spec)
 689 {
 690         if (check_pointer(&buf, end, s, spec))
 691                 return buf;
 692
 693         return string_nocheck(buf, end, s, spec);
 694 }
 695
 696 static char *pointer_string(char *buf, char *end,
 697                             const void *ptr,
 698                             struct printf_spec spec)
 699 {
 700         spec.base = 16;
 701         spec.flags |= SMALL;
 702         if (spec.field_width == -1) {
 703                 spec.field_width = 2 * sizeof(ptr);
 704                 spec.flags |= ZEROPAD;
 705         }
 706
 707         return number(buf, end, (unsigned long int)ptr, spec);
 708 }
 709
 710 /* Make pointers available for printing early in the boot sequence. */
 711 static int debug_boot_weak_hash __ro_after_init;
 712
 713 static int __init debug_boot_weak_hash_enable(char *str)
 714 {
 715         debug_boot_weak_hash = 1;
 716         pr_info("debug_boot_weak_hash enabled\n");
 717         return 0;
 718 }
 719 early_param("debug_boot_weak_hash", debug_boot_weak_hash_enable);
 720
 721 static DEFINE_STATIC_KEY_TRUE(not_filled_random_ptr_key);
 722 static siphash_key_t ptr_key __read_mostly;
 723
 724 static void enable_ptr_key_workfn(struct work_struct *work)
 725 {
 726         get_random_bytes(&ptr_key, sizeof(ptr_key));
 727         /* Needs to run from preemptible context */
 728         static_branch_disable(&not_filled_random_ptr_key);
 729 }
 730
 731 static DECLARE_WORK(enable_ptr_key_work, enable_ptr_key_workfn);
 732
 733 static void fill_random_ptr_key(struct random_ready_callback *unused)
 734 {
 735         /* This may be in an interrupt handler. */
 736         queue_work(system_unbound_wq, &enable_ptr_key_work);
 737 }
 738
 739 static struct random_ready_callback random_ready = {
 740         .func = fill_random_ptr_key
 741 };
 742
 743 static int __init initialize_ptr_random(void)
 744 {
 745         int key_size = sizeof(ptr_key);
 746         int ret;
 747
 748         /* Use hw RNG if available. */
 749         if (get_random_bytes_arch(&ptr_key, key_size) == key_size) {
 750                 static_branch_disable(&not_filled_random_ptr_key);
 751                 return 0;
 752         }
 753
 754         ret = add_random_ready_callback(&random_ready);
 755         if (!ret) {
 756                 return 0;
 757         } else if (ret == -EALREADY) {
 758                 /* This is in preemptible context */
 759                 enable_ptr_key_workfn(&enable_ptr_key_work);
 760                 return 0;
 761         }
 762
 763         return ret;
 764 }
 765 early_initcall(initialize_ptr_random);
 766
 767 /* Maps a pointer to a 32 bit unique identifier. */
 768 static inline int __ptr_to_hashval(const void *ptr, unsigned long *hashval_out)
 769 {
 770         unsigned long hashval;
 771
 772         if (static_branch_unlikely(&not_filled_random_ptr_key))
 773                 return -EAGAIN;
 774
 775 #ifdef CONFIG_64BIT
 776         hashval = (unsigned long)siphash_1u64((u64)ptr, &ptr_key);
 777         /*
 778          * Mask off the first 32 bits, this makes explicit that we have
 779          * modified the address (and 32 bits is plenty for a unique ID).
 780          */
 781         hashval = hashval & 0xffffffff;
 782 #else
 783         hashval = (unsigned long)siphash_1u32((u32)ptr, &ptr_key);
 784 #endif
 785         *hashval_out = hashval;
 786         return 0;
 787 }
 788
 789 int ptr_to_hashval(const void *ptr, unsigned long *hashval_out)
 790 {
 791         return __ptr_to_hashval(ptr, hashval_out);
 792 }
 793
 794 static char *ptr_to_id(char *buf, char *end, const void *ptr,
 795                        struct printf_spec spec)
 796 {
 797         const char *str = sizeof(ptr) == 8 ? "(____ptrval____)" : "(ptrval)";
 798         unsigned long hashval;
 799         int ret;
 800
 801         /*
 802          * Print the real pointer value for NULL and error pointers,
 803          * as they are not actual addresses.
 804          */
 805         if (IS_ERR_OR_NULL(ptr))
 806                 return pointer_string(buf, end, ptr, spec);
 807
 808         /* When debugging early boot use non-cryptographically secure hash. */
 809         if (unlikely(debug_boot_weak_hash)) {
 810                 hashval = hash_long((unsigned long)ptr, 32);
 811                 return pointer_string(buf, end, (const void *)hashval, spec);
 812         }
 813
 814         ret = __ptr_to_hashval(ptr, &hashval);
 815         if (ret) {
 816                 spec.field_width = 2 * sizeof(ptr);
 817                 /* string length must be less than default_width */
 818                 return error_string(buf, end, str, spec);
 819         }
 820
 821         return pointer_string(buf, end, (const void *)hashval, spec);
 822 }
 823
 824 int kptr_restrict __read_mostly;
 825
 826 static noinline_for_stack
 827 char *restricted_pointer(char *buf, char *end, const void *ptr,
 828                          struct printf_spec spec)
 829 {
 830         switch (kptr_restrict) {
 831         case 0:
 832                 /* Handle as %p, hash and do _not_ leak addresses. */
 833                 return ptr_to_id(buf, end, ptr, spec);
 834         case 1: {
 835                 const struct cred *cred;
 836
 837                 /*
 838                  * kptr_restrict==1 cannot be used in IRQ context
 839                  * because its test for CAP_SYSLOG would be meaningless.
 840                  */
 841                 if (in_irq() || in_serving_softirq() || in_nmi()) {
 842                         if (spec.field_width == -1)
 843                                 spec.field_width = 2 * sizeof(ptr);
 844                         return error_string(buf, end, "pK-error", spec);
 845                 }
 846
 847                 /*
 848                  * Only print the real pointer value if the current
 849                  * process has CAP_SYSLOG and is running with the
 850                  * same credentials it started with. This is because
 851                  * access to files is checked at open() time, but %pK
 852                  * checks permission at read() time. We don't want to
 853                  * leak pointer values if a binary opens a file using
 854                  * %pK and then elevates privileges before reading it.
 855                  */
 856                 cred = current_cred();
 857                 if (!has_capability_noaudit(current, CAP_SYSLOG) ||
 858                     !uid_eq(cred->euid, cred->uid) ||
 859                     !gid_eq(cred->egid, cred->gid))
 860                         ptr = NULL;
 861                 break;
 862         }
 863         case 2:
 864         default:
 865                 /* Always print 0's for %pK */
 866                 ptr = NULL;
 867                 break;
 868         }
 869
 870         return pointer_string(buf, end, ptr, spec);
 871 }
 872
 873 static noinline_for_stack
 874 char *dentry_name(char *buf, char *end, const struct dentry *d, struct printf_spec spec,
 875                   const char *fmt)
 876 {
 877         const char *array[4], *s;
 878         const struct dentry *p;
 879         int depth;
 880         int i, n;
 881
 882         switch (fmt[1]) {
 883                 case '2': case '3': case '4':
 884                         depth = fmt[1] - '0';
 885                         break;
 886                 default:
 887                         depth = 1;
 888         }
 889
 890         rcu_read_lock();
 891         for (i = 0; i < depth; i++, d = p) {
 892                 if (check_pointer(&buf, end, d, spec)) {
 893                         rcu_read_unlock();
 894                         return buf;
 895                 }
 896
 897                 p = READ_ONCE(d->d_parent);
 898                 array[i] = READ_ONCE(d->d_name.name);
 899                 if (p == d) {
 900                         if (i)
 901                                 array[i] = "";
 902                         i++;
 903                         break;
 904                 }
 905         }
 906         s = array[--i];
 907         for (n = 0; n != spec.precision; n++, buf++) {
 908                 char c = *s++;
 909                 if (!c) {
 910                         if (!i)
 911                                 break;
 912                         c = '/';
 913                         s = array[--i];
 914                 }
 915                 if (buf < end)
 916                         *buf = c;
 917         }
 918         rcu_read_unlock();
 919         return widen_string(buf, n, end, spec);
 920 }
 921
 922 static noinline_for_stack
 923 char *file_dentry_name(char *buf, char *end, const struct file *f,
 924                         struct printf_spec spec, const char *fmt)
 925 {
 926         if (check_pointer(&buf, end, f, spec))
 927                 return buf;
 928
 929         return dentry_name(buf, end, f->f_path.dentry, spec, fmt);
 930 }
 931 #ifdef CONFIG_BLOCK
 932 static noinline_for_stack
 933 char *bdev_name(char *buf, char *end, struct block_device *bdev,
 934                 struct printf_spec spec, const char *fmt)
 935 {
 936         struct gendisk *hd;
 937
 938         if (check_pointer(&buf, end, bdev, spec))
 939                 return buf;
 940
 941         hd = bdev->bd_disk;
 942         buf = string(buf, end, hd->disk_name, spec);
 943         if (bdev->bd_partno) {
 944                 if (isdigit(hd->disk_name[strlen(hd->disk_name)-1])) {
 945                         if (buf < end)
 946                                 *buf = 'p';
 947                         buf++;
 948                 }
 949                 buf = number(buf, end, bdev->bd_partno, spec);
 950         }
 951         return buf;
 952 }
 953 #endif
 954
 955 static noinline_for_stack
 956 char *symbol_string(char *buf, char *end, void *ptr,
 957                     struct printf_spec spec, const char *fmt)
 958 {
 959         unsigned long value;
 960 #ifdef CONFIG_KALLSYMS
 961         char sym[KSYM_SYMBOL_LEN];
 962 #endif
 963
 964         if (fmt[1] == 'R')
 965                 ptr = __builtin_extract_return_addr(ptr);
 966         value = (unsigned long)ptr;
 967
 968 #ifdef CONFIG_KALLSYMS
 969         if (*fmt == 'B')
 970                 sprint_backtrace(sym, value);
 971         else if (*fmt != 's')
 972                 sprint_symbol(sym, value);
 973         else
 974                 sprint_symbol_no_offset(sym, value);
 975
 976         return string_nocheck(buf, end, sym, spec);
 977 #else
 978         return special_hex_number(buf, end, value, sizeof(void *));
 979 #endif
 980 }
 981
 982 static const struct printf_spec default_str_spec = {
 983         .field_width = -1,
 984         .precision = -1,
 985 };
 986
 987 static const struct printf_spec default_flag_spec = {
 988         .base = 16,
 989         .precision = -1,
 990         .flags = SPECIAL | SMALL,
 991 };
 992
 993 static const struct printf_spec default_dec_spec = {
 994         .base = 10,
 995         .precision = -1,
 996 };
 997
 998 static const struct printf_spec default_dec02_spec = {
 999         .base = 10,
1000         .field_width = 2,
1001         .precision = -1,
1002         .flags = ZEROPAD,
1003 };
1004
1005 static const struct printf_spec default_dec04_spec = {
1006         .base = 10,
1007         .field_width = 4,
1008         .precision = -1,
1009         .flags = ZEROPAD,
1010 };
1011
1012 static noinline_for_stack
1013 char *resource_string(char *buf, char *end, struct resource *res,
1014                       struct printf_spec spec, const char *fmt)
1015 {
1016 #ifndef IO_RSRC_PRINTK_SIZE
1017 #define IO_RSRC_PRINTK_SIZE     6
1018 #endif
1019
1020 #ifndef MEM_RSRC_PRINTK_SIZE
1021 #define MEM_RSRC_PRINTK_SIZE    10
1022 #endif
1023         static const struct printf_spec io_spec = {
1024                 .base = 16,
1025                 .field_width = IO_RSRC_PRINTK_SIZE,
1026                 .precision = -1,
1027                 .flags = SPECIAL | SMALL | ZEROPAD,
1028         };
1029         static const struct printf_spec mem_spec = {
1030                 .base = 16,
1031                 .field_width = MEM_RSRC_PRINTK_SIZE,
1032                 .precision = -1,
1033                 .flags = SPECIAL | SMALL | ZEROPAD,
1034         };
1035         static const struct printf_spec bus_spec = {
1036                 .base = 16,
1037                 .field_width = 2,
1038                 .precision = -1,
1039                 .flags = SMALL | ZEROPAD,
1040         };
1041         static const struct printf_spec str_spec = {
1042                 .field_width = -1,
1043                 .precision = 10,
1044                 .flags = LEFT,
1045         };
1046
1047         /* 32-bit res (sizeof==4): 10 chars in dec, 10 in hex ("0x" + 8)
1048          * 64-bit res (sizeof==8): 20 chars in dec, 18 in hex ("0x" + 16) */
1049 #define RSRC_BUF_SIZE           ((2 * sizeof(resource_size_t)) + 4)
1050 #define FLAG_BUF_SIZE           (2 * sizeof(res->flags))
1051 #define DECODED_BUF_SIZE        sizeof("[mem - 64bit pref window disabled]")
1052 #define RAW_BUF_SIZE            sizeof("[mem - flags 0x]")
1053         char sym[max(2*RSRC_BUF_SIZE + DECODED_BUF_SIZE,
1054                      2*RSRC_BUF_SIZE + FLAG_BUF_SIZE + RAW_BUF_SIZE)];
1055
1056         char *p = sym, *pend = sym + sizeof(sym);
1057         int decode = (fmt[0] == 'R') ? 1 : 0;
1058         const struct printf_spec *specp;
1059
1060         if (check_pointer(&buf, end, res, spec))
1061                 return buf;
1062
1063         *p++ = '[';
1064         if (res->flags & IORESOURCE_IO) {
1065                 p = string_nocheck(p, pend, "io  ", str_spec);
1066                 specp = &io_spec;
1067         } else if (res->flags & IORESOURCE_MEM) {
1068                 p = string_nocheck(p, pend, "mem ", str_spec);
1069                 specp = &mem_spec;
1070         } else if (res->flags & IORESOURCE_IRQ) {
1071                 p = string_nocheck(p, pend, "irq ", str_spec);
1072                 specp = &default_dec_spec;
1073         } else if (res->flags & IORESOURCE_DMA) {
1074                 p = string_nocheck(p, pend, "dma ", str_spec);
1075                 specp = &default_dec_spec;
1076         } else if (res->flags & IORESOURCE_BUS) {
1077                 p = string_nocheck(p, pend, "bus ", str_spec);
1078                 specp = &bus_spec;
1079         } else {
1080                 p = string_nocheck(p, pend, "??? ", str_spec);
1081                 specp = &mem_spec;
1082                 decode = 0;
1083         }
1084         if (decode && res->flags & IORESOURCE_UNSET) {
1085                 p = string_nocheck(p, pend, "size ", str_spec);
1086                 p = number(p, pend, resource_size(res), *specp);
1087         } else {
1088                 p = number(p, pend, res->start, *specp);
1089                 if (res->start != res->end) {
1090                         *p++ = '-';
1091                         p = number(p, pend, res->end, *specp);
1092                 }
1093         }
1094         if (decode) {
1095                 if (res->flags & IORESOURCE_MEM_64)
1096                         p = string_nocheck(p, pend, " 64bit", str_spec);
1097                 if (res->flags & IORESOURCE_PREFETCH)
1098                         p = string_nocheck(p, pend, " pref", str_spec);
1099                 if (res->flags & IORESOURCE_WINDOW)
1100                         p = string_nocheck(p, pend, " window", str_spec);
1101                 if (res->flags & IORESOURCE_DISABLED)
1102                         p = string_nocheck(p, pend, " disabled", str_spec);
1103         } else {
1104                 p = string_nocheck(p, pend, " flags ", str_spec);
1105                 p = number(p, pend, res->flags, default_flag_spec);
1106         }
1107         *p++ = ']';
1108         *p = '\0';
1109
1110         return string_nocheck(buf, end, sym, spec);
1111 }
1112
1113 static noinline_for_stack
1114 char *hex_string(char *buf, char *end, u8 *addr, struct printf_spec spec,
1115                  const char *fmt)
1116 {
1117         int i, len = 1;         /* if we pass '%ph[CDN]', field width remains
1118                                    negative value, fallback to the default */
1119         char separator;
1120
1121         if (spec.field_width == 0)
1122                 /* nothing to print */
1123                 return buf;
1124
1125         if (check_pointer(&buf, end, addr, spec))
1126                 return buf;
1127
1128         switch (fmt[1]) {
1129         case 'C':
1130                 separator = ':';
1131                 break;
1132         case 'D':
1133                 separator = '-';
1134                 break;
1135         case 'N':
1136                 separator = 0;
1137                 break;
1138         default:
1139                 separator = ' ';
1140                 break;
1141         }
1142
1143         if (spec.field_width > 0)
1144                 len = min_t(int, spec.field_width, 64);
1145
1146         for (i = 0; i < len; ++i) {
1147                 if (buf < end)
1148                         *buf = hex_asc_hi(addr[i]);
1149                 ++buf;
1150                 if (buf < end)
1151                         *buf = hex_asc_lo(addr[i]);
1152                 ++buf;
1153
1154                 if (separator && i != len - 1) {
1155                         if (buf < end)
1156                                 *buf = separator;
1157                         ++buf;
1158                 }
1159         }
1160
1161         return buf;
1162 }
1163
1164 static noinline_for_stack
1165 char *bitmap_string(char *buf, char *end, unsigned long *bitmap,
1166                     struct printf_spec spec, const char *fmt)
1167 {
1168         const int CHUNKSZ = 32;
1169         int nr_bits = max_t(int, spec.field_width, 0);
1170         int i, chunksz;
1171         bool first = true;
1172
1173         if (check_pointer(&buf, end, bitmap, spec))
1174                 return buf;
1175
1176         /* reused to print numbers */
1177         spec = (struct printf_spec){ .flags = SMALL | ZEROPAD, .base = 16 };
1178
1179         chunksz = nr_bits & (CHUNKSZ - 1);
1180         if (chunksz == 0)
1181                 chunksz = CHUNKSZ;
1182
1183         i = ALIGN(nr_bits, CHUNKSZ) - CHUNKSZ;
1184         for (; i >= 0; i -= CHUNKSZ) {
1185                 u32 chunkmask, val;
1186                 int word, bit;
1187
1188                 chunkmask = ((1ULL << chunksz) - 1);
1189                 word = i / BITS_PER_LONG;
1190                 bit = i % BITS_PER_LONG;
1191                 val = (bitmap[word] >> bit) & chunkmask;
1192
1193                 if (!first) {
1194                         if (buf < end)
1195                                 *buf = ',';
1196                         buf++;
1197                 }
1198                 first = false;
1199
1200                 spec.field_width = DIV_ROUND_UP(chunksz, 4);
1201                 buf = number(buf, end, val, spec);
1202
1203                 chunksz = CHUNKSZ;
1204         }
1205         return buf;
1206 }
1207
1208 static noinline_for_stack
1209 char *bitmap_list_string(char *buf, char *end, unsigned long *bitmap,
1210                          struct printf_spec spec, const char *fmt)
1211 {
1212         int nr_bits = max_t(int, spec.field_width, 0);
1213         /* current bit is 'cur', most recently seen range is [rbot, rtop] */
1214         int cur, rbot, rtop;
1215         bool first = true;
1216
1217         if (check_pointer(&buf, end, bitmap, spec))
1218                 return buf;
1219
1220         rbot = cur = find_first_bit(bitmap, nr_bits);
1221         while (cur < nr_bits) {
1222                 rtop = cur;
1223                 cur = find_next_bit(bitmap, nr_bits, cur + 1);
1224                 if (cur < nr_bits && cur <= rtop + 1)
1225                         continue;
1226
1227                 if (!first) {
1228                         if (buf < end)
1229                                 *buf = ',';
1230                         buf++;
1231                 }
1232                 first = false;
1233
1234                 buf = number(buf, end, rbot, default_dec_spec);
1235                 if (rbot < rtop) {
1236                         if (buf < end)
1237                                 *buf = '-';
1238                         buf++;
1239
1240                         buf = number(buf, end, rtop, default_dec_spec);
1241                 }
1242
1243                 rbot = cur;
1244         }
1245         return buf;
1246 }
1247
1248 static noinline_for_stack
1249 char *mac_address_string(char *buf, char *end, u8 *addr,
1250                          struct printf_spec spec, const char *fmt)
1251 {
1252         char mac_addr[sizeof("xx:xx:xx:xx:xx:xx")];
1253         char *p = mac_addr;
1254         int i;
1255         char separator;
1256         bool reversed = false;
1257
1258         if (check_pointer(&buf, end, addr, spec))
1259                 return buf;
1260
1261         switch (fmt[1]) {
1262         case 'F':
1263                 separator = '-';
1264                 break;
1265
1266         case 'R':
1267                 reversed = true;
1268                 fallthrough;
1269
1270         default:
1271                 separator = ':';
1272                 break;
1273         }
1274
1275         for (i = 0; i < 6; i++) {
1276                 if (reversed)
1277                         p = hex_byte_pack(p, addr[5 - i]);
1278                 else
1279                         p = hex_byte_pack(p, addr[i]);
1280
1281                 if (fmt[0] == 'M' && i != 5)
1282                         *p++ = separator;
1283         }
1284         *p = '\0';
1285
1286         return string_nocheck(buf, end, mac_addr, spec);
1287 }
1288
1289 static noinline_for_stack
1290 char *ip4_string(char *p, const u8 *addr, const char *fmt)
1291 {
1292         int i;
1293         bool leading_zeros = (fmt[0] == 'i');
1294         int index;
1295         int step;
1296
1297         switch (fmt[2]) {
1298         case 'h':
1299 #ifdef __BIG_ENDIAN
1300                 index = 0;
1301                 step = 1;
1302 #else
1303                 index = 3;
1304                 step = -1;
1305 #endif
1306                 break;
1307         case 'l':
1308                 index = 3;
1309                 step = -1;
1310                 break;
1311         case 'n':
1312         case 'b':
1313         default:
1314                 index = 0;
1315                 step = 1;
1316                 break;
1317         }
1318         for (i = 0; i < 4; i++) {
1319                 char temp[4] __aligned(2);      /* hold each IP quad in reverse order */
1320                 int digits = put_dec_trunc8(temp, addr[index]) - temp;
1321                 if (leading_zeros) {
1322                         if (digits < 3)
1323                                 *p++ = '0';
1324                         if (digits < 2)
1325                                 *p++ = '0';
1326                 }
1327                 /* reverse the digits in the quad */
1328                 while (digits--)
1329                         *p++ = temp[digits];
1330                 if (i < 3)
1331                         *p++ = '.';
1332                 index += step;
1333         }
1334         *p = '\0';
1335
1336         return p;
1337 }
1338
1339 static noinline_for_stack
1340 char *ip6_compressed_string(char *p, const char *addr)
1341 {
1342         int i, j, range;
1343         unsigned char zerolength[8];
1344         int longest = 1;
1345         int colonpos = -1;
1346         u16 word;
1347         u8 hi, lo;
1348         bool needcolon = false;
1349         bool useIPv4;
1350         struct in6_addr in6;
1351
1352         memcpy(&in6, addr, sizeof(struct in6_addr));
1353
1354         useIPv4 = ipv6_addr_v4mapped(&in6) || ipv6_addr_is_isatap(&in6);
1355
1356         memset(zerolength, 0, sizeof(zerolength));
1357
1358         if (useIPv4)
1359                 range = 6;
1360         else
1361                 range = 8;
1362
1363         /* find position of longest 0 run */
1364         for (i = 0; i < range; i++) {
1365                 for (j = i; j < range; j++) {
1366                         if (in6.s6_addr16[j] != 0)
1367                                 break;
1368                         zerolength[i]++;
1369                 }
1370         }
1371         for (i = 0; i < range; i++) {
1372                 if (zerolength[i] > longest) {
1373                         longest = zerolength[i];
1374                         colonpos = i;
1375                 }
1376         }
1377         if (longest == 1)               /* don't compress a single 0 */
1378                 colonpos = -1;
1379
1380         /* emit address */
1381         for (i = 0; i < range; i++) {
1382                 if (i == colonpos) {
1383                         if (needcolon || i == 0)
1384                                 *p++ = ':';
1385                         *p++ = ':';
1386                         needcolon = false;
1387                         i += longest - 1;
1388                         continue;
1389                 }
1390                 if (needcolon) {
1391                         *p++ = ':';
1392                         needcolon = false;
1393                 }
1394                 /* hex u16 without leading 0s */
1395                 word = ntohs(in6.s6_addr16[i]);
1396                 hi = word >> 8;
1397                 lo = word & 0xff;
1398                 if (hi) {
1399                         if (hi > 0x0f)
1400                                 p = hex_byte_pack(p, hi);
1401                         else
1402                                 *p++ = hex_asc_lo(hi);
1403                         p = hex_byte_pack(p, lo);
1404                 }
1405                 else if (lo > 0x0f)
1406                         p = hex_byte_pack(p, lo);
1407                 else
1408                         *p++ = hex_asc_lo(lo);
1409                 needcolon = true;
1410         }
1411
1412         if (useIPv4) {
1413                 if (needcolon)
1414                         *p++ = ':';
1415                 p = ip4_string(p, &in6.s6_addr[12], "I4");
1416         }
1417         *p = '\0';
1418
1419         return p;
1420 }
1421
1422 static noinline_for_stack
1423 char *ip6_string(char *p, const char *addr, const char *fmt)
1424 {
1425         int i;
1426
1427         for (i = 0; i < 8; i++) {
1428                 p = hex_byte_pack(p, *addr++);
1429                 p = hex_byte_pack(p, *addr++);
1430                 if (fmt[0] == 'I' && i != 7)
1431                         *p++ = ':';
1432         }
1433         *p = '\0';
1434
1435         return p;
1436 }
1437
1438 static noinline_for_stack
1439 char *ip6_addr_string(char *buf, char *end, const u8 *addr,
1440                       struct printf_spec spec, const char *fmt)
1441 {
1442         char ip6_addr[sizeof("xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:255.255.255.255")];
1443
1444         if (fmt[0] == 'I' && fmt[2] == 'c')
1445                 ip6_compressed_string(ip6_addr, addr);
1446         else
1447                 ip6_string(ip6_addr, addr, fmt);
1448
1449         return string_nocheck(buf, end, ip6_addr, spec);
1450 }
1451
1452 static noinline_for_stack
1453 char *ip4_addr_string(char *buf, char *end, const u8 *addr,
1454                       struct printf_spec spec, const char *fmt)
1455 {
1456         char ip4_addr[sizeof("255.255.255.255")];
1457
1458         ip4_string(ip4_addr, addr, fmt);
1459
1460         return string_nocheck(buf, end, ip4_addr, spec);
1461 }
1462
1463 static noinline_for_stack
1464 char *ip6_addr_string_sa(char *buf, char *end, const struct sockaddr_in6 *sa,
1465                          struct printf_spec spec, const char *fmt)
1466 {
1467         bool have_p = false, have_s = false, have_f = false, have_c = false;
1468         char ip6_addr[sizeof("[xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:255.255.255.255]") +
1469                       sizeof(":12345") + sizeof("/123456789") +
1470                       sizeof("%1234567890")];
1471         char *p = ip6_addr, *pend = ip6_addr + sizeof(ip6_addr);
1472         const u8 *addr = (const u8 *) &sa->sin6_addr;
1473         char fmt6[2] = { fmt[0], '6' };
1474         u8 off = 0;
1475
1476         fmt++;
1477         while (isalpha(*++fmt)) {
1478                 switch (*fmt) {
1479                 case 'p':
1480                         have_p = true;
1481                         break;
1482                 case 'f':
1483                         have_f = true;
1484                         break;
1485                 case 's':
1486                         have_s = true;
1487                         break;
1488                 case 'c':
1489                         have_c = true;
1490                         break;
1491                 }
1492         }
1493
1494         if (have_p || have_s || have_f) {
1495                 *p = '[';
1496                 off = 1;
1497         }
1498
1499         if (fmt6[0] == 'I' && have_c)
1500                 p = ip6_compressed_string(ip6_addr + off, addr);
1501         else
1502                 p = ip6_string(ip6_addr + off, addr, fmt6);
1503
1504         if (have_p || have_s || have_f)
1505                 *p++ = ']';
1506
1507         if (have_p) {
1508                 *p++ = ':';
1509                 p = number(p, pend, ntohs(sa->sin6_port), spec);
1510         }
1511         if (have_f) {
1512                 *p++ = '/';
1513                 p = number(p, pend, ntohl(sa->sin6_flowinfo &
1514                                           IPV6_FLOWINFO_MASK), spec);
1515         }
1516         if (have_s) {
1517                 *p++ = '%';
1518                 p = number(p, pend, sa->sin6_scope_id, spec);
1519         }
1520         *p = '\0';
1521
1522         return string_nocheck(buf, end, ip6_addr, spec);
1523 }
1524
1525 static noinline_for_stack
1526 char *ip4_addr_string_sa(char *buf, char *end, const struct sockaddr_in *sa,
1527                          struct printf_spec spec, const char *fmt)
1528 {
1529         bool have_p = false;
1530         char *p, ip4_addr[sizeof("255.255.255.255") + sizeof(":12345")];
1531         char *pend = ip4_addr + sizeof(ip4_addr);
1532         const u8 *addr = (const u8 *) &sa->sin_addr.s_addr;
1533         char fmt4[3] = { fmt[0], '4', 0 };
1534
1535         fmt++;
1536         while (isalpha(*++fmt)) {
1537                 switch (*fmt) {
1538                 case 'p':
1539                         have_p = true;
1540                         break;
1541                 case 'h':
1542                 case 'l':
1543                 case 'n':
1544                 case 'b':
1545                         fmt4[2] = *fmt;
1546                         break;
1547                 }
1548         }
1549
1550         p = ip4_string(ip4_addr, addr, fmt4);
1551         if (have_p) {
1552                 *p++ = ':';
1553                 p = number(p, pend, ntohs(sa->sin_port), spec);
1554         }
1555         *p = '\0';
1556
1557         return string_nocheck(buf, end, ip4_addr, spec);
1558 }
1559
1560 static noinline_for_stack
1561 char *ip_addr_string(char *buf, char *end, const void *ptr,
1562                      struct printf_spec spec, const char *fmt)
1563 {
1564         char *err_fmt_msg;
1565
1566         if (check_pointer(&buf, end, ptr, spec))
1567                 return buf;
1568
1569         switch (fmt[1]) {
1570         case '6':
1571                 return ip6_addr_string(buf, end, ptr, spec, fmt);
1572         case '4':
1573                 return ip4_addr_string(buf, end, ptr, spec, fmt);
1574         case 'S': {
1575                 const union {
1576                         struct sockaddr         raw;
1577                         struct sockaddr_in      v4;
1578                         struct sockaddr_in6     v6;
1579                 } *sa = ptr;
1580
1581                 switch (sa->raw.sa_family) {
1582                 case AF_INET:
1583                         return ip4_addr_string_sa(buf, end, &sa->v4, spec, fmt);
1584                 case AF_INET6:
1585                         return ip6_addr_string_sa(buf, end, &sa->v6, spec, fmt);
1586                 default:
1587                         return error_string(buf, end, "(einval)", spec);
1588                 }}
1589         }
1590
1591         err_fmt_msg = fmt[0] == 'i' ? "(%pi?)" : "(%pI?)";
1592         return error_string(buf, end, err_fmt_msg, spec);
1593 }
1594
1595 static noinline_for_stack
1596 char *escaped_string(char *buf, char *end, u8 *addr, struct printf_spec spec,
1597                      const char *fmt)
1598 {
1599         bool found = true;
1600         int count = 1;
1601         unsigned int flags = 0;
1602         int len;
1603
1604         if (spec.field_width == 0)
1605                 return buf;                             /* nothing to print */
1606
1607         if (check_pointer(&buf, end, addr, spec))
1608                 return buf;
1609
1610         do {
1611                 switch (fmt[count++]) {
1612                 case 'a':
1613                         flags |= ESCAPE_ANY;
1614                         break;
1615                 case 'c':
1616                         flags |= ESCAPE_SPECIAL;
1617                         break;
1618                 case 'h':
1619                         flags |= ESCAPE_HEX;
1620                         break;
1621                 case 'n':
1622                         flags |= ESCAPE_NULL;
1623                         break;
1624                 case 'o':
1625                         flags |= ESCAPE_OCTAL;
1626                         break;
1627                 case 'p':
1628                         flags |= ESCAPE_NP;
1629                         break;
1630                 case 's':
1631                         flags |= ESCAPE_SPACE;
1632                         break;
1633                 default:
1634                         found = false;
1635                         break;
1636                 }
1637         } while (found);
1638
1639         if (!flags)
1640                 flags = ESCAPE_ANY_NP;
1641
1642         len = spec.field_width < 0 ? 1 : spec.field_width;
1643
1644         /*
1645          * string_escape_mem() writes as many characters as it can to
1646          * the given buffer, and returns the total size of the output
1647          * had the buffer been big enough.
1648          */
1649         buf += string_escape_mem(addr, len, buf, buf < end ? end - buf : 0, flags, NULL);
1650
1651         return buf;
1652 }
1653
1654 static char *va_format(char *buf, char *end, struct va_format *va_fmt,
1655                        struct printf_spec spec, const char *fmt)
1656 {
1657         va_list va;
1658
1659         if (check_pointer(&buf, end, va_fmt, spec))
1660                 return buf;
1661
1662         va_copy(va, *va_fmt->va);
1663         buf += vsnprintf(buf, end > buf ? end - buf : 0, va_fmt->fmt, va);
1664         va_end(va);
1665
1666         return buf;
1667 }
1668
1669 static noinline_for_stack
1670 char *uuid_string(char *buf, char *end, const u8 *addr,
1671                   struct printf_spec spec, const char *fmt)
1672 {
1673         char uuid[UUID_STRING_LEN + 1];
1674         char *p = uuid;
1675         int i;
1676         const u8 *index = uuid_index;
1677         bool uc = false;
1678
1679         if (check_pointer(&buf, end, addr, spec))
1680                 return buf;
1681
1682         switch (*(++fmt)) {
1683         case 'L':
1684                 uc = true;
1685                 fallthrough;
1686         case 'l':
1687                 index = guid_index;
1688                 break;
1689         case 'B':
1690                 uc = true;
1691                 break;
1692         }
1693
1694         for (i = 0; i < 16; i++) {
1695                 if (uc)
1696                         p = hex_byte_pack_upper(p, addr[index[i]]);
1697                 else
1698                         p = hex_byte_pack(p, addr[index[i]]);
1699                 switch (i) {
1700                 case 3:
1701                 case 5:
1702                 case 7:
1703                 case 9:
1704                         *p++ = '-';
1705                         break;
1706                 }
1707         }
1708
1709         *p = 0;
1710
1711         return string_nocheck(buf, end, uuid, spec);
1712 }
1713
1714 static noinline_for_stack
1715 char *netdev_bits(char *buf, char *end, const void *addr,
1716                   struct printf_spec spec,  const char *fmt)
1717 {
1718         unsigned long long num;
1719         int size;
1720
1721         if (check_pointer(&buf, end, addr, spec))
1722                 return buf;
1723
1724         switch (fmt[1]) {
1725         case 'F':
1726                 num = *(const netdev_features_t *)addr;
1727                 size = sizeof(netdev_features_t);
1728                 break;
1729         default:
1730                 return error_string(buf, end, "(%pN?)", spec);
1731         }
1732
1733         return special_hex_number(buf, end, num, size);
1734 }
1735
1736 static noinline_for_stack
1737 char *address_val(char *buf, char *end, const void *addr,
1738                   struct printf_spec spec, const char *fmt)
1739 {
1740         unsigned long long num;
1741         int size;
1742
1743         if (check_pointer(&buf, end, addr, spec))
1744                 return buf;
1745
1746         switch (fmt[1]) {
1747         case 'd':
1748                 num = *(const dma_addr_t *)addr;
1749                 size = sizeof(dma_addr_t);
1750                 break;
1751         case 'p':
1752         default:
1753                 num = *(const phys_addr_t *)addr;
1754                 size = sizeof(phys_addr_t);
1755                 break;
1756         }
1757
1758         return special_hex_number(buf, end, num, size);
1759 }
1760
1761 static noinline_for_stack
1762 char *date_str(char *buf, char *end, const struct rtc_time *tm, bool r)
1763 {
1764         int year = tm->tm_year + (r ? 0 : 1900);
1765         int mon = tm->tm_mon + (r ? 0 : 1);
1766
1767         buf = number(buf, end, year, default_dec04_spec);
1768         if (buf < end)
1769                 *buf = '-';
1770         buf++;
1771
1772         buf = number(buf, end, mon, default_dec02_spec);
1773         if (buf < end)
1774                 *buf = '-';
1775         buf++;
1776
1777         return number(buf, end, tm->tm_mday, default_dec02_spec);
1778 }
1779
1780 static noinline_for_stack
1781 char *time_str(char *buf, char *end, const struct rtc_time *tm, bool r)
1782 {
1783         buf = number(buf, end, tm->tm_hour, default_dec02_spec);
1784         if (buf < end)
1785                 *buf = ':';
1786         buf++;
1787
1788         buf = number(buf, end, tm->tm_min, default_dec02_spec);
1789         if (buf < end)
1790                 *buf = ':';
1791         buf++;
1792
1793         return number(buf, end, tm->tm_sec, default_dec02_spec);
1794 }
1795
1796 static noinline_for_stack
1797 char *rtc_str(char *buf, char *end, const struct rtc_time *tm,
1798               struct printf_spec spec, const char *fmt)
1799 {
1800         bool have_t = true, have_d = true;
1801         bool raw = false;
1802         int count = 2;
1803
1804         if (check_pointer(&buf, end, tm, spec))
1805                 return buf;
1806
1807         switch (fmt[count]) {
1808         case 'd':
1809                 have_t = false;
1810                 count++;
1811                 break;
1812         case 't':
1813                 have_d = false;
1814                 count++;
1815                 break;
1816         }
1817
1818         raw = fmt[count] == 'r';
1819
1820         if (have_d)
1821                 buf = date_str(buf, end, tm, raw);
1822         if (have_d && have_t) {
1823                 /* Respect ISO 8601 */
1824                 if (buf < end)
1825                         *buf = 'T';
1826                 buf++;
1827         }
1828         if (have_t)
1829                 buf = time_str(buf, end, tm, raw);
1830
1831         return buf;
1832 }
1833
1834 static noinline_for_stack
1835 char *time64_str(char *buf, char *end, const time64_t time,
1836                  struct printf_spec spec, const char *fmt)
1837 {
1838         struct rtc_time rtc_time;
1839         struct tm tm;
1840
1841         time64_to_tm(time, 0, &tm);
1842
1843         rtc_time.tm_sec = tm.tm_sec;
1844         rtc_time.tm_min = tm.tm_min;
1845         rtc_time.tm_hour = tm.tm_hour;
1846         rtc_time.tm_mday = tm.tm_mday;
1847         rtc_time.tm_mon = tm.tm_mon;
1848         rtc_time.tm_year = tm.tm_year;
1849         rtc_time.tm_wday = tm.tm_wday;
1850         rtc_time.tm_yday = tm.tm_yday;
1851
1852         rtc_time.tm_isdst = 0;
1853
1854         return rtc_str(buf, end, &rtc_time, spec, fmt);
1855 }
1856
1857 static noinline_for_stack
1858 char *time_and_date(char *buf, char *end, void *ptr, struct printf_spec spec,
1859                     const char *fmt)
1860 {
1861         switch (fmt[1]) {
1862         case 'R':
1863                 return rtc_str(buf, end, (const struct rtc_time *)ptr, spec, fmt);
1864         case 'T':
1865                 return time64_str(buf, end, *(const time64_t *)ptr, spec, fmt);
1866         default:
1867                 return error_string(buf, end, "(%pt?)", spec);
1868         }
1869 }
1870
1871 static noinline_for_stack
1872 char *clock(char *buf, char *end, struct clk *clk, struct printf_spec spec,
1873             const char *fmt)
1874 {
1875         if (!IS_ENABLED(CONFIG_HAVE_CLK))
1876                 return error_string(buf, end, "(%pC?)", spec);
1877
1878         if (check_pointer(&buf, end, clk, spec))
1879                 return buf;
1880
1881         switch (fmt[1]) {
1882         case 'n':
1883         default:
1884 #ifdef CONFIG_COMMON_CLK
1885                 return string(buf, end, __clk_get_name(clk), spec);
1886 #else
1887                 return ptr_to_id(buf, end, clk, spec);
1888 #endif
1889         }
1890 }
1891
1892 static
1893 char *format_flags(char *buf, char *end, unsigned long flags,
1894                                         const struct trace_print_flags *names)
1895 {
1896         unsigned long mask;
1897
1898         for ( ; flags && names->name; names++) {
1899                 mask = names->mask;
1900                 if ((flags & mask) != mask)
1901                         continue;
1902
1903                 buf = string(buf, end, names->name, default_str_spec);
1904
1905                 flags &= ~mask;
1906                 if (flags) {
1907                         if (buf < end)
1908                                 *buf = '|';
1909                         buf++;
1910                 }
1911         }
1912
1913         if (flags)
1914                 buf = number(buf, end, flags, default_flag_spec);
1915
1916         return buf;
1917 }
1918
1919 static noinline_for_stack
1920 char *flags_string(char *buf, char *end, void *flags_ptr,
1921                    struct printf_spec spec, const char *fmt)
1922 {
1923         unsigned long flags;
1924         const struct trace_print_flags *names;
1925
1926         if (check_pointer(&buf, end, flags_ptr, spec))
1927                 return buf;
1928
1929         switch (fmt[1]) {
1930         case 'p':
1931                 flags = *(unsigned long *)flags_ptr;
1932                 /* Remove zone id */
1933                 flags &= (1UL << NR_PAGEFLAGS) - 1;
1934                 names = pageflag_names;
1935                 break;
1936         case 'v':
1937                 flags = *(unsigned long *)flags_ptr;
1938                 names = vmaflag_names;
1939                 break;
1940         case 'g':
1941                 flags = (__force unsigned long)(*(gfp_t *)flags_ptr);
1942                 names = gfpflag_names;
1943                 break;
1944         default:
1945                 return error_string(buf, end, "(%pG?)", spec);
1946         }
1947
1948         return format_flags(buf, end, flags, names);
1949 }
1950
1951 static noinline_for_stack
1952 char *fwnode_full_name_string(struct fwnode_handle *fwnode, char *buf,
1953                               char *end)
1954 {
1955         int depth;
1956
1957         /* Loop starting from the root node to the current node. */
1958         for (depth = fwnode_count_parents(fwnode); depth >= 0; depth--) {
1959                 struct fwnode_handle *__fwnode =
1960                         fwnode_get_nth_parent(fwnode, depth);
1961
1962                 buf = string(buf, end, fwnode_get_name_prefix(__fwnode),
1963                              default_str_spec);
1964                 buf = string(buf, end, fwnode_get_name(__fwnode),
1965                              default_str_spec);
1966
1967                 fwnode_handle_put(__fwnode);
1968         }
1969
1970         return buf;
1971 }
1972
1973 static noinline_for_stack
1974 char *device_node_string(char *buf, char *end, struct device_node *dn,
1975                          struct printf_spec spec, const char *fmt)
1976 {
1977         char tbuf[sizeof("xxxx") + 1];
1978         const char *p;
1979         int ret;
1980         char *buf_start = buf;
1981         struct property *prop;
1982         bool has_mult, pass;
1983
1984         struct printf_spec str_spec = spec;
1985         str_spec.field_width = -1;
1986
1987         if (fmt[0] != 'F')
1988                 return error_string(buf, end, "(%pO?)", spec);
1989
1990         if (!IS_ENABLED(CONFIG_OF))
1991                 return error_string(buf, end, "(%pOF?)", spec);
1992
1993         if (check_pointer(&buf, end, dn, spec))
1994                 return buf;
1995
1996         /* simple case without anything any more format specifiers */
1997         fmt++;
1998         if (fmt[0] == '\0' || strcspn(fmt,"fnpPFcC") > 0)
1999                 fmt = "f";
2000
2001         for (pass = false; strspn(fmt,"fnpPFcC"); fmt++, pass = true) {
2002                 int precision;
2003                 if (pass) {
2004                         if (buf < end)
2005                                 *buf = ':';
2006                         buf++;
2007                 }
2008
2009                 switch (*fmt) {
2010                 case 'f':       /* full_name */
2011                         buf = fwnode_full_name_string(of_fwnode_handle(dn), buf,
2012                                                       end);
2013                         break;
2014                 case 'n':       /* name */
2015                         p = fwnode_get_name(of_fwnode_handle(dn));
2016                         precision = str_spec.precision;
2017                         str_spec.precision = strchrnul(p, '@') - p;
2018                         buf = string(buf, end, p, str_spec);
2019                         str_spec.precision = precision;
2020                         break;
2021                 case 'p':       /* phandle */
2022                         buf = number(buf, end, (unsigned int)dn->phandle, default_dec_spec);
2023                         break;
2024                 case 'P':       /* path-spec */
2025                         p = fwnode_get_name(of_fwnode_handle(dn));
2026                         if (!p[1])
2027                                 p = "/";
2028                         buf = string(buf, end, p, str_spec);
2029                         break;
2030                 case 'F':       /* flags */
2031                         tbuf[0] = of_node_check_flag(dn, OF_DYNAMIC) ? 'D' : '-';
2032                         tbuf[1] = of_node_check_flag(dn, OF_DETACHED) ? 'd' : '-';
2033                         tbuf[2] = of_node_check_flag(dn, OF_POPULATED) ? 'P' : '-';
2034                         tbuf[3] = of_node_check_flag(dn, OF_POPULATED_BUS) ? 'B' : '-';
2035                         tbuf[4] = 0;
2036                         buf = string_nocheck(buf, end, tbuf, str_spec);
2037                         break;
2038                 case 'c':       /* major compatible string */
2039                         ret = of_property_read_string(dn, "compatible", &p);
2040                         if (!ret)
2041                                 buf = string(buf, end, p, str_spec);
2042                         break;
2043                 case 'C':       /* full compatible string */
2044                         has_mult = false;
2045                         of_property_for_each_string(dn, "compatible", prop, p) {
2046                                 if (has_mult)
2047                                         buf = string_nocheck(buf, end, ",", str_spec);
2048                                 buf = string_nocheck(buf, end, "\"", str_spec);
2049                                 buf = string(buf, end, p, str_spec);
2050                                 buf = string_nocheck(buf, end, "\"", str_spec);
2051
2052                                 has_mult = true;
2053                         }
2054                         break;
2055                 default:
2056                         break;
2057                 }
2058         }
2059
2060         return widen_string(buf, buf - buf_start, end, spec);
2061 }
2062
2063 static noinline_for_stack
2064 char *fwnode_string(char *buf, char *end, struct fwnode_handle *fwnode,
2065                     struct printf_spec spec, const char *fmt)
2066 {
2067         struct printf_spec str_spec = spec;
2068         char *buf_start = buf;
2069
2070         str_spec.field_width = -1;
2071
2072         if (*fmt != 'w')
2073                 return error_string(buf, end, "(%pf?)", spec);
2074
2075         if (check_pointer(&buf, end, fwnode, spec))
2076                 return buf;
2077
2078         fmt++;
2079
2080         switch (*fmt) {
2081         case 'P':       /* name */
2082                 buf = string(buf, end, fwnode_get_name(fwnode), str_spec);
2083                 break;
2084         case 'f':       /* full_name */
2085         default:
2086                 buf = fwnode_full_name_string(fwnode, buf, end);
2087                 break;
2088         }
2089
2090         return widen_string(buf, buf - buf_start, end, spec);
2091 }
2092
2093 /*
2094  * Show a '%p' thing.  A kernel extension is that the '%p' is followed
2095  * by an extra set of alphanumeric characters that are extended format
2096  * specifiers.
2097  *
2098  * Please update scripts/checkpatch.pl when adding/removing conversion
2099  * characters.  (Search for "check for vsprintf extension").
2100  *
2101  * Right now we handle:
2102  *
2103  * - 'S' For symbolic direct pointers (or function descriptors) with offset
2104  * - 's' For symbolic direct pointers (or function descriptors) without offset
2105  * - '[Ss]R' as above with __builtin_extract_return_addr() translation
2106  * - '[Ff]' %pf and %pF were obsoleted and later removed in favor of
2107  *          %ps and %pS. Be careful when re-using these specifiers.
2108  * - 'B' For backtraced symbolic direct pointers with offset
2109  * - 'R' For decoded struct resource, e.g., [mem 0x0-0x1f 64bit pref]
2110  * - 'r' For raw struct resource, e.g., [mem 0x0-0x1f flags 0x201]
2111  * - 'b[l]' For a bitmap, the number of bits is determined by the field
2112  *       width which must be explicitly specified either as part of the
2113  *       format string '%32b[l]' or through '%*b[l]', [l] selects
2114  *       range-list format instead of hex format
2115  * - 'M' For a 6-byte MAC address, it prints the address in the
2116  *       usual colon-separated hex notation
2117  * - 'm' For a 6-byte MAC address, it prints the hex address without colons
2118  * - 'MF' For a 6-byte MAC FDDI address, it prints the address
2119  *       with a dash-separated hex notation
2120  * - '[mM]R' For a 6-byte MAC address, Reverse order (Bluetooth)
2121  * - 'I' [46] for IPv4/IPv6 addresses printed in the usual way
2122  *       IPv4 uses dot-separated decimal without leading 0's (1.2.3.4)
2123  *       IPv6 uses colon separated network-order 16 bit hex with leading 0's
2124  *       [S][pfs]
2125  *       Generic IPv4/IPv6 address (struct sockaddr *) that falls back to
2126  *       [4] or [6] and is able to print port [p], flowinfo [f], scope [s]
2127  * - 'i' [46] for 'raw' IPv4/IPv6 addresses
2128  *       IPv6 omits the colons (01020304...0f)
2129  *       IPv4 uses dot-separated decimal with leading 0's (010.123.045.006)
2130  *       [S][pfs]
2131  *       Generic IPv4/IPv6 address (struct sockaddr *) that falls back to
2132  *       [4] or [6] and is able to print port [p], flowinfo [f], scope [s]
2133  * - '[Ii][4S][hnbl]' IPv4 addresses in host, network, big or little endian order
2134  * - 'I[6S]c' for IPv6 addresses printed as specified by
2135  *       https://tools.ietf.org/html/rfc5952
2136  * - 'E[achnops]' For an escaped buffer, where rules are defined by combination
2137  *                of the following flags (see string_escape_mem() for the
2138  *                details):
2139  *                  a - ESCAPE_ANY
2140  *                  c - ESCAPE_SPECIAL
2141  *                  h - ESCAPE_HEX
2142  *                  n - ESCAPE_NULL
2143  *                  o - ESCAPE_OCTAL
2144  *                  p - ESCAPE_NP
2145  *                  s - ESCAPE_SPACE
2146  *                By default ESCAPE_ANY_NP is used.
2147  * - 'U' For a 16 byte UUID/GUID, it prints the UUID/GUID in the form
2148  *       "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx"
2149  *       Options for %pU are:
2150  *         b big endian lower case hex (default)
2151  *         B big endian UPPER case hex
2152  *         l little endian lower case hex
2153  *         L little endian UPPER case hex
2154  *           big endian output byte order is:
2155  *             [0][1][2][3]-[4][5]-[6][7]-[8][9]-[10][11][12][13][14][15]
2156  *           little endian output byte order is:
2157  *             [3][2][1][0]-[5][4]-[7][6]-[8][9]-[10][11][12][13][14][15]
2158  * - 'V' For a struct va_format which contains a format string * and va_list *,
2159  *       call vsnprintf(->format, *->va_list).
2160  *       Implements a "recursive vsnprintf".
2161  *       Do not use this feature without some mechanism to verify the
2162  *       correctness of the format string and va_list arguments.
2163  * - 'K' For a kernel pointer that should be hidden from unprivileged users
2164  * - 'NF' For a netdev_features_t
2165  * - 'h[CDN]' For a variable-length buffer, it prints it as a hex string with
2166  *            a certain separator (' ' by default):
2167  *              C colon
2168  *              D dash
2169  *              N no separator
2170  *            The maximum supported length is 64 bytes of the input. Consider
2171  *            to use print_hex_dump() for the larger input.
2172  * - 'a[pd]' For address types [p] phys_addr_t, [d] dma_addr_t and derivatives
2173  *           (default assumed to be phys_addr_t, passed by reference)
2174  * - 'd[234]' For a dentry name (optionally 2-4 last components)
2175  * - 'D[234]' Same as 'd' but for a struct file
2176  * - 'g' For block_device name (gendisk + partition number)
2177  * - 't[RT][dt][r]' For time and date as represented by:
2178  *      R    struct rtc_time
2179  *      T    time64_t
2180  * - 'C' For a clock, it prints the name (Common Clock Framework) or address
2181  *       (legacy clock framework) of the clock
2182  * - 'Cn' For a clock, it prints the name (Common Clock Framework) or address
2183  *        (legacy clock framework) of the clock
2184  * - 'G' For flags to be printed as a collection of symbolic strings that would
2185  *       construct the specific value. Supported flags given by option:
2186  *       p page flags (see struct page) given as pointer to unsigned long
2187  *       g gfp flags (GFP_* and __GFP_*) given as pointer to gfp_t
2188  *       v vma flags (VM_*) given as pointer to unsigned long
2189  * - 'OF[fnpPcCF]'  For a device tree object
2190  *                  Without any optional arguments prints the full_name
2191  *                  f device node full_name
2192  *                  n device node name
2193  *                  p device node phandle
2194  *                  P device node path spec (name + @unit)
2195  *                  F device node flags
2196  *                  c major compatible string
2197  *                  C full compatible string
2198  * - 'fw[fP]'   For a firmware node (struct fwnode_handle) pointer
2199  *              Without an option prints the full name of the node
2200  *              f full name
2201  *              P node name, including a possible unit address
2202  * - 'x' For printing the address. Equivalent to "%lx".
2203  * - '[ku]s' For a BPF/tracing related format specifier, e.g. used out of
2204  *           bpf_trace_printk() where [ku] prefix specifies either kernel (k)
2205  *           or user (u) memory to probe, and:
2206  *              s a string, equivalent to "%s" on direct vsnprintf() use
2207  *
2208  * ** When making changes please also update:
2209  *      Documentation/core-api/printk-formats.rst
2210  *
2211  * Note: The default behaviour (unadorned %p) is to hash the address,
2212  * rendering it useful as a unique identifier.
2213  */
2214 static noinline_for_stack
2215 char *pointer(const char *fmt, char *buf, char *end, void *ptr,
2216               struct printf_spec spec)
2217 {
2218         switch (*fmt) {
2219         case 'S':
2220         case 's':
2221                 ptr = dereference_symbol_descriptor(ptr);
2222                 fallthrough;
2223         case 'B':
2224                 return symbol_string(buf, end, ptr, spec, fmt);
2225         case 'R':
2226         case 'r':
2227                 return resource_string(buf, end, ptr, spec, fmt);
2228         case 'h':
2229                 return hex_string(buf, end, ptr, spec, fmt);
2230         case 'b':
2231                 switch (fmt[1]) {
2232                 case 'l':
2233                         return bitmap_list_string(buf, end, ptr, spec, fmt);
2234                 default:
2235                         return bitmap_string(buf, end, ptr, spec, fmt);
2236                 }
2237         case 'M':                       /* Colon separated: 00:01:02:03:04:05 */
2238         case 'm':                       /* Contiguous: 000102030405 */
2239                                         /* [mM]F (FDDI) */
2240                                         /* [mM]R (Reverse order; Bluetooth) */
2241                 return mac_address_string(buf, end, ptr, spec, fmt);
2242         case 'I':                       /* Formatted IP supported
2243                                          * 4:   1.2.3.4
2244                                          * 6:   0001:0203:...:0708
2245                                          * 6c:  1::708 or 1::1.2.3.4
2246                                          */
2247         case 'i':                       /* Contiguous:
2248                                          * 4:   001.002.003.004
2249                                          * 6:   000102...0f
2250                                          */
2251                 return ip_addr_string(buf, end, ptr, spec, fmt);
2252         case 'E':
2253                 return escaped_string(buf, end, ptr, spec, fmt);
2254         case 'U':
2255                 return uuid_string(buf, end, ptr, spec, fmt);
2256         case 'V':
2257                 return va_format(buf, end, ptr, spec, fmt);
2258         case 'K':
2259                 return restricted_pointer(buf, end, ptr, spec);
2260         case 'N':
2261                 return netdev_bits(buf, end, ptr, spec, fmt);
2262         case 'a':
2263                 return address_val(buf, end, ptr, spec, fmt);
2264         case 'd':
2265                 return dentry_name(buf, end, ptr, spec, fmt);
2266         case 't':
2267                 return time_and_date(buf, end, ptr, spec, fmt);
2268         case 'C':
2269                 return clock(buf, end, ptr, spec, fmt);
2270         case 'D':
2271                 return file_dentry_name(buf, end, ptr, spec, fmt);
2272 #ifdef CONFIG_BLOCK
2273         case 'g':
2274                 return bdev_name(buf, end, ptr, spec, fmt);
2275 #endif
2276
2277         case 'G':
2278                 return flags_string(buf, end, ptr, spec, fmt);
2279         case 'O':
2280                 return device_node_string(buf, end, ptr, spec, fmt + 1);
2281         case 'f':
2282                 return fwnode_string(buf, end, ptr, spec, fmt + 1);
2283         case 'x':
2284                 return pointer_string(buf, end, ptr, spec);
2285         case 'e':
2286                 /* %pe with a non-ERR_PTR gets treated as plain %p */
2287                 if (!IS_ERR(ptr))
2288                         break;
2289                 return err_ptr(buf, end, ptr, spec);
2290         case 'u':
2291         case 'k':
2292                 switch (fmt[1]) {
2293                 case 's':
2294                         return string(buf, end, ptr, spec);
2295                 default:
2296                         return error_string(buf, end, "(einval)", spec);
2297                 }
2298         }
2299
2300         /* default is to _not_ leak addresses, hash before printing */
2301         return ptr_to_id(buf, end, ptr, spec);
2302 }
2303
2304 /*
2305  * Helper function to decode printf style format.
2306  * Each call decode a token from the format and return the
2307  * number of characters read (or likely the delta where it wants
2308  * to go on the next call).
2309  * The decoded token is returned through the parameters
2310  *
2311  * 'h', 'l', or 'L' for integer fields
2312  * 'z' support added 23/7/1999 S.H.
2313  * 'z' changed to 'Z' --davidm 1/25/99
2314  * 'Z' changed to 'z' --adobriyan 2017-01-25
2315  * 't' added for ptrdiff_t
2316  *
2317  * @fmt: the format string
2318  * @type of the token returned
2319  * @flags: various flags such as +, -, # tokens..
2320  * @field_width: overwritten width
2321  * @base: base of the number (octal, hex, ...)
2322  * @precision: precision of a number
2323  * @qualifier: qualifier of a number (long, size_t, ...)
2324  */
2325 static noinline_for_stack
2326 int format_decode(const char *fmt, struct printf_spec *spec)
2327 {
2328         const char *start = fmt;
2329         char qualifier;
2330
2331         /* we finished early by reading the field width */
2332         if (spec->type == FORMAT_TYPE_WIDTH) {
2333                 if (spec->field_width < 0) {
2334                         spec->field_width = -spec->field_width;
2335                         spec->flags |= LEFT;
2336                 }
2337                 spec->type = FORMAT_TYPE_NONE;
2338                 goto precision;
2339         }
2340
2341         /* we finished early by reading the precision */
2342         if (spec->type == FORMAT_TYPE_PRECISION) {
2343                 if (spec->precision < 0)
2344                         spec->precision = 0;
2345
2346                 spec->type = FORMAT_TYPE_NONE;
2347                 goto qualifier;
2348         }
2349
2350         /* By default */
2351         spec->type = FORMAT_TYPE_NONE;
2352
2353         for (; *fmt ; ++fmt) {
2354                 if (*fmt == '%')
2355                         break;
2356         }
2357
2358         /* Return the current non-format string */
2359         if (fmt != start || !*fmt)
2360                 return fmt - start;
2361
2362         /* Process flags */
2363         spec->flags = 0;
2364
2365         while (1) { /* this also skips first '%' */
2366                 bool found = true;
2367
2368                 ++fmt;
2369
2370                 switch (*fmt) {
2371                 case '-': spec->flags |= LEFT;    break;
2372                 case '+': spec->flags |= PLUS;    break;
2373                 case ' ': spec->flags |= SPACE;   break;
2374                 case '#': spec->flags |= SPECIAL; break;
2375                 case '0': spec->flags |= ZEROPAD; break;
2376                 default:  found = false;
2377                 }
2378
2379                 if (!found)
2380                         break;
2381         }
2382
2383         /* get field width */
2384         spec->field_width = -1;
2385
2386         if (isdigit(*fmt))
2387                 spec->field_width = skip_atoi(&fmt);
2388         else if (*fmt == '*') {
2389                 /* it's the next argument */
2390                 spec->type = FORMAT_TYPE_WIDTH;
2391                 return ++fmt - start;
2392         }
2393
2394 precision:
2395         /* get the precision */
2396         spec->precision = -1;
2397         if (*fmt == '.') {
2398                 ++fmt;
2399                 if (isdigit(*fmt)) {
2400                         spec->precision = skip_atoi(&fmt);
2401                         if (spec->precision < 0)
2402                                 spec->precision = 0;
2403                 } else if (*fmt == '*') {
2404                         /* it's the next argument */
2405                         spec->type = FORMAT_TYPE_PRECISION;
2406                         return ++fmt - start;
2407                 }
2408         }
2409
2410 qualifier:
2411         /* get the conversion qualifier */
2412         qualifier = 0;
2413         if (*fmt == 'h' || _tolower(*fmt) == 'l' ||
2414             *fmt == 'z' || *fmt == 't') {
2415                 qualifier = *fmt++;
2416                 if (unlikely(qualifier == *fmt)) {
2417                         if (qualifier == 'l') {
2418                                 qualifier = 'L';
2419                                 ++fmt;
2420                         } else if (qualifier == 'h') {
2421                                 qualifier = 'H';
2422                                 ++fmt;
2423                         }
2424                 }
2425         }
2426
2427         /* default base */
2428         spec->base = 10;
2429         switch (*fmt) {
2430         case 'c':
2431                 spec->type = FORMAT_TYPE_CHAR;
2432                 return ++fmt - start;
2433
2434         case 's':
2435                 spec->type = FORMAT_TYPE_STR;
2436                 return ++fmt - start;
2437
2438         case 'p':
2439                 spec->type = FORMAT_TYPE_PTR;
2440                 return ++fmt - start;
2441
2442         case '%':
2443                 spec->type = FORMAT_TYPE_PERCENT_CHAR;
2444                 return ++fmt - start;
2445
2446         /* integer number formats - set up the flags and "break" */
2447         case 'o':
2448                 spec->base = 8;
2449                 break;
2450
2451         case 'x':
2452                 spec->flags |= SMALL;
2453                 fallthrough;
2454
2455         case 'X':
2456                 spec->base = 16;
2457                 break;
2458
2459         case 'd':
2460         case 'i':
2461                 spec->flags |= SIGN;
2462                 break;
2463         case 'u':
2464                 break;
2465
2466         case 'n':
2467                 /*
2468                  * Since %n poses a greater security risk than
2469                  * utility, treat it as any other invalid or
2470                  * unsupported format specifier.
2471                  */
2472                 fallthrough;
2473
2474         default:
2475                 WARN_ONCE(1, "Please remove unsupported %%%c in format string\n", *fmt);
2476                 spec->type = FORMAT_TYPE_INVALID;
2477                 return fmt - start;
2478         }
2479
2480         if (qualifier == 'L')
2481                 spec->type = FORMAT_TYPE_LONG_LONG;
2482         else if (qualifier == 'l') {
2483                 BUILD_BUG_ON(FORMAT_TYPE_ULONG + SIGN != FORMAT_TYPE_LONG);
2484                 spec->type = FORMAT_TYPE_ULONG + (spec->flags & SIGN);
2485         } else if (qualifier == 'z') {
2486                 spec->type = FORMAT_TYPE_SIZE_T;
2487         } else if (qualifier == 't') {
2488                 spec->type = FORMAT_TYPE_PTRDIFF;
2489         } else if (qualifier == 'H') {
2490                 BUILD_BUG_ON(FORMAT_TYPE_UBYTE + SIGN != FORMAT_TYPE_BYTE);
2491                 spec->type = FORMAT_TYPE_UBYTE + (spec->flags & SIGN);
2492         } else if (qualifier == 'h') {
2493                 BUILD_BUG_ON(FORMAT_TYPE_USHORT + SIGN != FORMAT_TYPE_SHORT);
2494                 spec->type = FORMAT_TYPE_USHORT + (spec->flags & SIGN);
2495         } else {
2496                 BUILD_BUG_ON(FORMAT_TYPE_UINT + SIGN != FORMAT_TYPE_INT);
2497                 spec->type = FORMAT_TYPE_UINT + (spec->flags & SIGN);
2498         }
2499
2500         return ++fmt - start;
2501 }
2502
2503 static void
2504 set_field_width(struct printf_spec *spec, int width)
2505 {
2506         spec->field_width = width;
2507         if (WARN_ONCE(spec->field_width != width, "field width %d too large", width)) {
2508                 spec->field_width = clamp(width, -FIELD_WIDTH_MAX, FIELD_WIDTH_MAX);
2509         }
2510 }
2511
2512 static void
2513 set_precision(struct printf_spec *spec, int prec)
2514 {
2515         spec->precision = prec;
2516         if (WARN_ONCE(spec->precision != prec, "precision %d too large", prec)) {
2517                 spec->precision = clamp(prec, 0, PRECISION_MAX);
2518         }
2519 }
2520
2521 /**
2522  * vsnprintf - Format a string and place it in a buffer
2523  * @buf: The buffer to place the result into
2524  * @size: The size of the buffer, including the trailing null space
2525  * @fmt: The format string to use
2526  * @args: Arguments for the format string
2527  *
2528  * This function generally follows C99 vsnprintf, but has some
2529  * extensions and a few limitations:
2530  *
2531  *  - ``%n`` is unsupported
2532  *  - ``%p*`` is handled by pointer()
2533  *
2534  * See pointer() or Documentation/core-api/printk-formats.rst for more
2535  * extensive description.
2536  *
2537  * **Please update the documentation in both places when making changes**
2538  *
2539  * The return value is the number of characters which would
2540  * be generated for the given input, excluding the trailing
2541  * '\0', as per ISO C99. If you want to have the exact
2542  * number of characters written into @buf as return value
2543  * (not including the trailing '\0'), use vscnprintf(). If the
2544  * return is greater than or equal to @size, the resulting
2545  * string is truncated.
2546  *
2547  * If you're not already dealing with a va_list consider using snprintf().
2548  */
2549 int vsnprintf(char *buf, size_t size, const char *fmt, va_list args)
2550 {
2551         unsigned long long num;
2552         char *str, *end;
2553         struct printf_spec spec = {0};
2554
2555         /* Reject out-of-range values early.  Large positive sizes are
2556            used for unknown buffer sizes. */
2557         if (WARN_ON_ONCE(size > INT_MAX))
2558                 return 0;
2559
2560         str = buf;
2561         end = buf + size;
2562
2563         /* Make sure end is always >= buf */
2564         if (end < buf) {
2565                 end = ((void *)-1);
2566                 size = end - buf;
2567         }
2568
2569         while (*fmt) {
2570                 const char *old_fmt = fmt;
2571                 int read = format_decode(fmt, &spec);
2572
2573                 fmt += read;
2574
2575                 switch (spec.type) {
2576                 case FORMAT_TYPE_NONE: {
2577                         int copy = read;
2578                         if (str < end) {
2579                                 if (copy > end - str)
2580                                         copy = end - str;
2581                                 memcpy(str, old_fmt, copy);
2582                         }
2583                         str += read;
2584                         break;
2585                 }
2586
2587                 case FORMAT_TYPE_WIDTH:
2588                         set_field_width(&spec, va_arg(args, int));
2589                         break;
2590
2591                 case FORMAT_TYPE_PRECISION:
2592                         set_precision(&spec, va_arg(args, int));
2593                         break;
2594
2595                 case FORMAT_TYPE_CHAR: {
2596                         char c;
2597
2598                         if (!(spec.flags & LEFT)) {
2599                                 while (--spec.field_width > 0) {
2600                                         if (str < end)
2601                                                 *str = ' ';
2602                                         ++str;
2603
2604                                 }
2605                         }
2606                         c = (unsigned char) va_arg(args, int);
2607                         if (str < end)
2608                                 *str = c;
2609                         ++str;
2610                         while (--spec.field_width > 0) {
2611                                 if (str < end)
2612                                         *str = ' ';
2613                                 ++str;
2614                         }
2615                         break;
2616                 }
2617
2618                 case FORMAT_TYPE_STR:
2619                         str = string(str, end, va_arg(args, char *), spec);
2620                         break;
2621
2622                 case FORMAT_TYPE_PTR:
2623                         str = pointer(fmt, str, end, va_arg(args, void *),
2624                                       spec);
2625                         while (isalnum(*fmt))
2626                                 fmt++;
2627                         break;
2628
2629                 case FORMAT_TYPE_PERCENT_CHAR:
2630                         if (str < end)
2631                                 *str = '%';
2632                         ++str;
2633                         break;
2634
2635                 case FORMAT_TYPE_INVALID:
2636                         /*
2637                          * Presumably the arguments passed gcc's type
2638                          * checking, but there is no safe or sane way
2639                          * for us to continue parsing the format and
2640                          * fetching from the va_list; the remaining
2641                          * specifiers and arguments would be out of
2642                          * sync.
2643                          */
2644                         goto out;
2645
2646                 default:
2647                         switch (spec.type) {
2648                         case FORMAT_TYPE_LONG_LONG:
2649                                 num = va_arg(args, long long);
2650                                 break;
2651                         case FORMAT_TYPE_ULONG:
2652                                 num = va_arg(args, unsigned long);
2653                                 break;
2654                         case FORMAT_TYPE_LONG:
2655                                 num = va_arg(args, long);
2656                                 break;
2657                         case FORMAT_TYPE_SIZE_T:
2658                                 if (spec.flags & SIGN)
2659                                         num = va_arg(args, ssize_t);
2660                                 else
2661                                         num = va_arg(args, size_t);
2662                                 break;
2663                         case FORMAT_TYPE_PTRDIFF:
2664                                 num = va_arg(args, ptrdiff_t);
2665                                 break;
2666                         case FORMAT_TYPE_UBYTE:
2667                                 num = (unsigned char) va_arg(args, int);
2668                                 break;
2669                         case FORMAT_TYPE_BYTE:
2670                                 num = (signed char) va_arg(args, int);
2671                                 break;
2672                         case FORMAT_TYPE_USHORT:
2673                                 num = (unsigned short) va_arg(args, int);
2674                                 break;
2675                         case FORMAT_TYPE_SHORT:
2676                                 num = (short) va_arg(args, int);
2677                                 break;
2678                         case FORMAT_TYPE_INT:
2679                                 num = (int) va_arg(args, int);
2680                                 break;
2681                         default:
2682                                 num = va_arg(args, unsigned int);
2683                         }
2684
2685                         str = number(str, end, num, spec);
2686                 }
2687         }
2688
2689 out:
2690         if (size > 0) {
2691                 if (str < end)
2692                         *str = '\0';
2693                 else
2694                         end[-1] = '\0';
2695         }
2696
2697         /* the trailing null byte doesn't count towards the total */
2698         return str-buf;
2699
2700 }
2701 EXPORT_SYMBOL(vsnprintf);
2702
2703 /**
2704  * vscnprintf - Format a string and place it in a buffer
2705  * @buf: The buffer to place the result into
2706  * @size: The size of the buffer, including the trailing null space
2707  * @fmt: The format string to use
2708  * @args: Arguments for the format string
2709  *
2710  * The return value is the number of characters which have been written into
2711  * the @buf not including the trailing '\0'. If @size is == 0 the function
2712  * returns 0.
2713  *
2714  * If you're not already dealing with a va_list consider using scnprintf().
2715  *
2716  * See the vsnprintf() documentation for format string extensions over C99.
2717  */
2718 int vscnprintf(char *buf, size_t size, const char *fmt, va_list args)
2719 {
2720         int i;
2721
2722         i = vsnprintf(buf, size, fmt, args);
2723
2724         if (likely(i < size))
2725                 return i;
2726         if (size != 0)
2727                 return size - 1;
2728         return 0;
2729 }
2730 EXPORT_SYMBOL(vscnprintf);
2731
2732 /**
2733  * snprintf - Format a string and place it in a buffer
2734  * @buf: The buffer to place the result into
2735  * @size: The size of the buffer, including the trailing null space
2736  * @fmt: The format string to use
2737  * @...: Arguments for the format string
2738  *
2739  * The return value is the number of characters which would be
2740  * generated for the given input, excluding the trailing null,
2741  * as per ISO C99.  If the return is greater than or equal to
2742  * @size, the resulting string is truncated.
2743  *
2744  * See the vsnprintf() documentation for format string extensions over C99.
2745  */
2746 int snprintf(char *buf, size_t size, const char *fmt, ...)
2747 {
2748         va_list args;
2749         int i;
2750
2751         va_start(args, fmt);
2752         i = vsnprintf(buf, size, fmt, args);
2753         va_end(args);
2754
2755         return i;
2756 }
2757 EXPORT_SYMBOL(snprintf);
2758
2759 /**
2760  * scnprintf - Format a string and place it in a buffer
2761  * @buf: The buffer to place the result into
2762  * @size: The size of the buffer, including the trailing null space
2763  * @fmt: The format string to use
2764  * @...: Arguments for the format string
2765  *
2766  * The return value is the number of characters written into @buf not including
2767  * the trailing '\0'. If @size is == 0 the function returns 0.
2768  */
2769
2770 int scnprintf(char *buf, size_t size, const char *fmt, ...)
2771 {
2772         va_list args;
2773         int i;
2774
2775         va_start(args, fmt);
2776         i = vscnprintf(buf, size, fmt, args);
2777         va_end(args);
2778
2779         return i;
2780 }
2781 EXPORT_SYMBOL(scnprintf);
2782
2783 /**
2784  * vsprintf - Format a string and place it in a buffer
2785  * @buf: The buffer to place the result into
2786  * @fmt: The format string to use
2787  * @args: Arguments for the format string
2788  *
2789  * The function returns the number of characters written
2790  * into @buf. Use vsnprintf() or vscnprintf() in order to avoid
2791  * buffer overflows.
2792  *
2793  * If you're not already dealing with a va_list consider using sprintf().
2794  *
2795  * See the vsnprintf() documentation for format string extensions over C99.
2796  */
2797 int vsprintf(char *buf, const char *fmt, va_list args)
2798 {
2799         return vsnprintf(buf, INT_MAX, fmt, args);
2800 }
2801 EXPORT_SYMBOL(vsprintf);
2802
2803 /**
2804  * sprintf - Format a string and place it in a buffer
2805  * @buf: The buffer to place the result into
2806  * @fmt: The format string to use
2807  * @...: Arguments for the format string
2808  *
2809  * The function returns the number of characters written
2810  * into @buf. Use snprintf() or scnprintf() in order to avoid
2811  * buffer overflows.
2812  *
2813  * See the vsnprintf() documentation for format string extensions over C99.
2814  */
2815 int sprintf(char *buf, const char *fmt, ...)
2816 {
2817         va_list args;
2818         int i;
2819
2820         va_start(args, fmt);
2821         i = vsnprintf(buf, INT_MAX, fmt, args);
2822         va_end(args);
2823
2824         return i;
2825 }
2826 EXPORT_SYMBOL(sprintf);
2827
2828 #ifdef CONFIG_BINARY_PRINTF
2829 /*
2830  * bprintf service:
2831  * vbin_printf() - VA arguments to binary data
2832  * bstr_printf() - Binary data to text string
2833  */
2834
2835 /**
2836  * vbin_printf - Parse a format string and place args' binary value in a buffer
2837  * @bin_buf: The buffer to place args' binary value
2838  * @size: The size of the buffer(by words(32bits), not characters)
2839  * @fmt: The format string to use
2840  * @args: Arguments for the format string
2841  *
2842  * The format follows C99 vsnprintf, except %n is ignored, and its argument
2843  * is skipped.
2844  *
2845  * The return value is the number of words(32bits) which would be generated for
2846  * the given input.
2847  *
2848  * NOTE:
2849  * If the return value is greater than @size, the resulting bin_buf is NOT
2850  * valid for bstr_printf().
2851  */
2852 int vbin_printf(u32 *bin_buf, size_t size, const char *fmt, va_list args)
2853 {
2854         struct printf_spec spec = {0};
2855         char *str, *end;
2856         int width;
2857
2858         str = (char *)bin_buf;
2859         end = (char *)(bin_buf + size);
2860
2861 #define save_arg(type)                                                  \
2862 ({                                                                      \
2863         unsigned long long value;                                       \
2864         if (sizeof(type) == 8) {                                        \
2865                 unsigned long long val8;                                \
2866                 str = PTR_ALIGN(str, sizeof(u32));                      \
2867                 val8 = va_arg(args, unsigned long long);                \
2868                 if (str + sizeof(type) <= end) {                        \
2869                         *(u32 *)str = *(u32 *)&val8;                    \
2870                         *(u32 *)(str + 4) = *((u32 *)&val8 + 1);        \
2871                 }                                                       \
2872                 value = val8;                                           \
2873         } else {                                                        \
2874                 unsigned int val4;                                      \
2875                 str = PTR_ALIGN(str, sizeof(type));                     \
2876                 val4 = va_arg(args, int);                               \
2877                 if (str + sizeof(type) <= end)                          \
2878                         *(typeof(type) *)str = (type)(long)val4;        \
2879                 value = (unsigned long long)val4;                       \
2880         }                                                               \
2881         str += sizeof(type);                                            \
2882         value;                                                          \
2883 })
2884
2885         while (*fmt) {
2886                 int read = format_decode(fmt, &spec);
2887
2888                 fmt += read;
2889
2890                 switch (spec.type) {
2891                 case FORMAT_TYPE_NONE:
2892                 case FORMAT_TYPE_PERCENT_CHAR:
2893                         break;
2894                 case FORMAT_TYPE_INVALID:
2895                         goto out;
2896
2897                 case FORMAT_TYPE_WIDTH:
2898                 case FORMAT_TYPE_PRECISION:
2899                         width = (int)save_arg(int);
2900                         /* Pointers may require the width */
2901                         if (*fmt == 'p')
2902                                 set_field_width(&spec, width);
2903                         break;
2904
2905                 case FORMAT_TYPE_CHAR:
2906                         save_arg(char);
2907                         break;
2908
2909                 case FORMAT_TYPE_STR: {
2910                         const char *save_str = va_arg(args, char *);
2911                         const char *err_msg;
2912                         size_t len;
2913
2914                         err_msg = check_pointer_msg(save_str);
2915                         if (err_msg)
2916                                 save_str = err_msg;
2917
2918                         len = strlen(save_str) + 1;
2919                         if (str + len < end)
2920                                 memcpy(str, save_str, len);
2921                         str += len;
2922                         break;
2923                 }
2924
2925                 case FORMAT_TYPE_PTR:
2926                         /* Dereferenced pointers must be done now */
2927                         switch (*fmt) {
2928                         /* Dereference of functions is still OK */
2929                         case 'S':
2930                         case 's':
2931                         case 'x':
2932                         case 'K':
2933                         case 'e':
2934                                 save_arg(void *);
2935                                 break;
2936                         default:
2937                                 if (!isalnum(*fmt)) {
2938                                         save_arg(void *);
2939                                         break;
2940                                 }
2941                                 str = pointer(fmt, str, end, va_arg(args, void *),
2942                                               spec);
2943                                 if (str + 1 < end)
2944                                         *str++ = '\0';
2945                                 else
2946                                         end[-1] = '\0'; /* Must be nul terminated */
2947                         }
2948                         /* skip all alphanumeric pointer suffixes */
2949                         while (isalnum(*fmt))
2950                                 fmt++;
2951                         break;
2952
2953                 default:
2954                         switch (spec.type) {
2955
2956                         case FORMAT_TYPE_LONG_LONG:
2957                                 save_arg(long long);
2958                                 break;
2959                         case FORMAT_TYPE_ULONG:
2960                         case FORMAT_TYPE_LONG:
2961                                 save_arg(unsigned long);
2962                                 break;
2963                         case FORMAT_TYPE_SIZE_T:
2964                                 save_arg(size_t);
2965                                 break;
2966                         case FORMAT_TYPE_PTRDIFF:
2967                                 save_arg(ptrdiff_t);
2968                                 break;
2969                         case FORMAT_TYPE_UBYTE:
2970                         case FORMAT_TYPE_BYTE:
2971                                 save_arg(char);
2972                                 break;
2973                         case FORMAT_TYPE_USHORT:
2974                         case FORMAT_TYPE_SHORT:
2975                                 save_arg(short);
2976                                 break;
2977                         default:
2978                                 save_arg(int);
2979                         }
2980                 }
2981         }
2982
2983 out:
2984         return (u32 *)(PTR_ALIGN(str, sizeof(u32))) - bin_buf;
2985 #undef save_arg
2986 }
2987 EXPORT_SYMBOL_GPL(vbin_printf);
2988
2989 /**
2990  * bstr_printf - Format a string from binary arguments and place it in a buffer
2991  * @buf: The buffer to place the result into
2992  * @size: The size of the buffer, including the trailing null space
2993  * @fmt: The format string to use
2994  * @bin_buf: Binary arguments for the format string
2995  *
2996  * This function like C99 vsnprintf, but the difference is that vsnprintf gets
2997  * arguments from stack, and bstr_printf gets arguments from @bin_buf which is
2998  * a binary buffer that generated by vbin_printf.
2999  *
3000  * The format follows C99 vsnprintf, but has some extensions:
3001  *  see vsnprintf comment for details.
3002  *
3003  * The return value is the number of characters which would
3004  * be generated for the given input, excluding the trailing
3005  * '\0', as per ISO C99. If you want to have the exact
3006  * number of characters written into @buf as return value
3007  * (not including the trailing '\0'), use vscnprintf(). If the
3008  * return is greater than or equal to @size, the resulting
3009  * string is truncated.
3010  */
3011 int bstr_printf(char *buf, size_t size, const char *fmt, const u32 *bin_buf)
3012 {
3013         struct printf_spec spec = {0};
3014         char *str, *end;
3015         const char *args = (const char *)bin_buf;
3016
3017         if (WARN_ON_ONCE(size > INT_MAX))
3018                 return 0;
3019
3020         str = buf;
3021         end = buf + size;
3022
3023 #define get_arg(type)                                                   \
3024 ({                                                                      \
3025         typeof(type) value;                                             \
3026         if (sizeof(type) == 8) {                                        \
3027                 args = PTR_ALIGN(args, sizeof(u32));                    \
3028                 *(u32 *)&value = *(u32 *)args;                          \
3029                 *((u32 *)&value + 1) = *(u32 *)(args + 4);              \
3030         } else {                                                        \
3031                 args = PTR_ALIGN(args, sizeof(type));                   \
3032                 value = *(typeof(type) *)args;                          \
3033         }                                                               \
3034         args += sizeof(type);                                           \
3035         value;                                                          \
3036 })
3037
3038         /* Make sure end is always >= buf */
3039         if (end < buf) {
3040                 end = ((void *)-1);
3041                 size = end - buf;
3042         }
3043
3044         while (*fmt) {
3045                 const char *old_fmt = fmt;
3046                 int read = format_decode(fmt, &spec);
3047
3048                 fmt += read;
3049
3050                 switch (spec.type) {
3051                 case FORMAT_TYPE_NONE: {
3052                         int copy = read;
3053                         if (str < end) {
3054                                 if (copy > end - str)
3055                                         copy = end - str;
3056                                 memcpy(str, old_fmt, copy);
3057                         }
3058                         str += read;
3059                         break;
3060                 }
3061
3062                 case FORMAT_TYPE_WIDTH:
3063                         set_field_width(&spec, get_arg(int));
3064                         break;
3065
3066                 case FORMAT_TYPE_PRECISION:
3067                         set_precision(&spec, get_arg(int));
3068                         break;
3069
3070                 case FORMAT_TYPE_CHAR: {
3071                         char c;
3072
3073                         if (!(spec.flags & LEFT)) {
3074                                 while (--spec.field_width > 0) {
3075                                         if (str < end)
3076                                                 *str = ' ';
3077                                         ++str;
3078                                 }
3079                         }
3080                         c = (unsigned char) get_arg(char);
3081                         if (str < end)
3082                                 *str = c;
3083                         ++str;
3084                         while (--spec.field_width > 0) {
3085                                 if (str < end)
3086                                         *str = ' ';
3087                                 ++str;
3088                         }
3089                         break;
3090                 }
3091
3092                 case FORMAT_TYPE_STR: {
3093                         const char *str_arg = args;
3094                         args += strlen(str_arg) + 1;
3095                         str = string(str, end, (char *)str_arg, spec);
3096                         break;
3097                 }
3098
3099                 case FORMAT_TYPE_PTR: {
3100                         bool process = false;
3101                         int copy, len;
3102                         /* Non function dereferences were already done */
3103                         switch (*fmt) {
3104                         case 'S':
3105                         case 's':
3106                         case 'F':
3107                         case 'f':
3108                         case 'x':
3109                         case 'K':
3110                         case 'e':
3111                                 process = true;
3112                                 break;
3113                         default:
3114                                 if (!isalnum(*fmt)) {
3115                                         process = true;
3116                                         break;
3117                                 }
3118                                 /* Pointer dereference was already processed */
3119                                 if (str < end) {
3120                                         len = copy = strlen(args);
3121                                         if (copy > end - str)
3122                                                 copy = end - str;
3123                                         memcpy(str, args, copy);
3124                                         str += len;
3125                                         args += len + 1;
3126                                 }
3127                         }
3128                         if (process)
3129                                 str = pointer(fmt, str, end, get_arg(void *), spec);
3130
3131                         while (isalnum(*fmt))
3132                                 fmt++;
3133                         break;
3134                 }
3135
3136                 case FORMAT_TYPE_PERCENT_CHAR:
3137                         if (str < end)
3138                                 *str = '%';
3139                         ++str;
3140                         break;
3141
3142                 case FORMAT_TYPE_INVALID:
3143                         goto out;
3144
3145                 default: {
3146                         unsigned long long num;
3147
3148                         switch (spec.type) {
3149
3150                         case FORMAT_TYPE_LONG_LONG:
3151                                 num = get_arg(long long);
3152                                 break;
3153                         case FORMAT_TYPE_ULONG:
3154                         case FORMAT_TYPE_LONG:
3155                                 num = get_arg(unsigned long);
3156                                 break;
3157                         case FORMAT_TYPE_SIZE_T:
3158                                 num = get_arg(size_t);
3159                                 break;
3160                         case FORMAT_TYPE_PTRDIFF:
3161                                 num = get_arg(ptrdiff_t);
3162                                 break;
3163                         case FORMAT_TYPE_UBYTE:
3164                                 num = get_arg(unsigned char);
3165                                 break;
3166                         case FORMAT_TYPE_BYTE:
3167                                 num = get_arg(signed char);
3168                                 break;
3169                         case FORMAT_TYPE_USHORT:
3170                                 num = get_arg(unsigned short);
3171                                 break;
3172                         case FORMAT_TYPE_SHORT:
3173                                 num = get_arg(short);
3174                                 break;
3175                         case FORMAT_TYPE_UINT:
3176                                 num = get_arg(unsigned int);
3177                                 break;
3178                         default:
3179                                 num = get_arg(int);
3180                         }
3181
3182                         str = number(str, end, num, spec);
3183                 } /* default: */
3184                 } /* switch(spec.type) */
3185         } /* while(*fmt) */
3186
3187 out:
3188         if (size > 0) {
3189                 if (str < end)
3190                         *str = '\0';
3191                 else
3192                         end[-1] = '\0';
3193         }
3194
3195 #undef get_arg
3196
3197         /* the trailing null byte doesn't count towards the total */
3198         return str - buf;
3199 }
3200 EXPORT_SYMBOL_GPL(bstr_printf);
3201
3202 /**
3203  * bprintf - Parse a format string and place args' binary value in a buffer
3204  * @bin_buf: The buffer to place args' binary value
3205  * @size: The size of the buffer(by words(32bits), not characters)
3206  * @fmt: The format string to use
3207  * @...: Arguments for the format string
3208  *
3209  * The function returns the number of words(u32) written
3210  * into @bin_buf.
3211  */
3212 int bprintf(u32 *bin_buf, size_t size, const char *fmt, ...)
3213 {
3214         va_list args;
3215         int ret;
3216
3217         va_start(args, fmt);
3218         ret = vbin_printf(bin_buf, size, fmt, args);
3219         va_end(args);
3220
3221         return ret;
3222 }
3223 EXPORT_SYMBOL_GPL(bprintf);
3224
3225 #endif /* CONFIG_BINARY_PRINTF */
3226
3227 /**
3228  * vsscanf - Unformat a buffer into a list of arguments
3229  * @buf:        input buffer
3230  * @fmt:        format of buffer
3231  * @args:       arguments
3232  */
3233 int vsscanf(const char *buf, const char *fmt, va_list args)
3234 {
3235         const char *str = buf;
3236         char *next;
3237         char digit;
3238         int num = 0;
3239         u8 qualifier;
3240         unsigned int base;
3241         union {
3242                 long long s;
3243                 unsigned long long u;
3244         } val;
3245         s16 field_width;
3246         bool is_sign;
3247
3248         while (*fmt) {
3249                 /* skip any white space in format */
3250                 /* white space in format matchs any amount of
3251                  * white space, including none, in the input.
3252                  */
3253                 if (isspace(*fmt)) {
3254                         fmt = skip_spaces(++fmt);
3255                         str = skip_spaces(str);
3256                 }
3257
3258                 /* anything that is not a conversion must match exactly */
3259                 if (*fmt != '%' && *fmt) {
3260                         if (*fmt++ != *str++)
3261                                 break;
3262                         continue;
3263                 }
3264
3265                 if (!*fmt)
3266                         break;
3267                 ++fmt;
3268
3269                 /* skip this conversion.
3270                  * advance both strings to next white space
3271                  */
3272                 if (*fmt == '*') {
3273                         if (!*str)
3274                                 break;
3275                         while (!isspace(*fmt) && *fmt != '%' && *fmt) {
3276                                 /* '%*[' not yet supported, invalid format */
3277                                 if (*fmt == '[')
3278                                         return num;
3279                                 fmt++;
3280                         }
3281                         while (!isspace(*str) && *str)
3282                                 str++;
3283                         continue;
3284                 }
3285
3286                 /* get field width */
3287                 field_width = -1;
3288                 if (isdigit(*fmt)) {
3289                         field_width = skip_atoi(&fmt);
3290                         if (field_width <= 0)
3291                                 break;
3292                 }
3293
3294                 /* get conversion qualifier */
3295                 qualifier = -1;
3296                 if (*fmt == 'h' || _tolower(*fmt) == 'l' ||
3297                     *fmt == 'z') {
3298                         qualifier = *fmt++;
3299                         if (unlikely(qualifier == *fmt)) {
3300                                 if (qualifier == 'h') {
3301                                         qualifier = 'H';
3302                                         fmt++;
3303                                 } else if (qualifier == 'l') {
3304                                         qualifier = 'L';
3305                                         fmt++;
3306                                 }
3307                         }
3308                 }
3309
3310                 if (!*fmt)
3311                         break;
3312
3313                 if (*fmt == 'n') {
3314                         /* return number of characters read so far */
3315                         *va_arg(args, int *) = str - buf;
3316                         ++fmt;
3317                         continue;
3318                 }
3319
3320                 if (!*str)
3321                         break;
3322
3323                 base = 10;
3324                 is_sign = false;
3325
3326                 switch (*fmt++) {
3327                 case 'c':
3328                 {
3329                         char *s = (char *)va_arg(args, char*);
3330                         if (field_width == -1)
3331                                 field_width = 1;
3332                         do {
3333                                 *s++ = *str++;
3334                         } while (--field_width > 0 && *str);
3335                         num++;
3336                 }
3337                 continue;
3338                 case 's':
3339                 {
3340                         char *s = (char *)va_arg(args, char *);
3341                         if (field_width == -1)
3342                                 field_width = SHRT_MAX;
3343                         /* first, skip leading white space in buffer */
3344                         str = skip_spaces(str);
3345
3346                         /* now copy until next white space */
3347                         while (*str && !isspace(*str) && field_width--)
3348                                 *s++ = *str++;
3349                         *s = '\0';
3350                         num++;
3351                 }
3352                 continue;
3353                 /*
3354                  * Warning: This implementation of the '[' conversion specifier
3355                  * deviates from its glibc counterpart in the following ways:
3356                  * (1) It does NOT support ranges i.e. '-' is NOT a special
3357                  *     character
3358                  * (2) It cannot match the closing bracket ']' itself
3359                  * (3) A field width is required
3360                  * (4) '%*[' (discard matching input) is currently not supported
3361                  *
3362                  * Example usage:
3363                  * ret = sscanf("00:0a:95","%2[^:]:%2[^:]:%2[^:]",
3364                  *              buf1, buf2, buf3);
3365                  * if (ret < 3)
3366                  *    // etc..
3367                  */
3368                 case '[':
3369                 {
3370                         char *s = (char *)va_arg(args, char *);
3371                         DECLARE_BITMAP(set, 256) = {0};
3372                         unsigned int len = 0;
3373                         bool negate = (*fmt == '^');
3374
3375                         /* field width is required */
3376                         if (field_width == -1)
3377                                 return num;
3378
3379                         if (negate)
3380                                 ++fmt;
3381
3382                         for ( ; *fmt && *fmt != ']'; ++fmt, ++len)
3383                                 set_bit((u8)*fmt, set);
3384
3385                         /* no ']' or no character set found */
3386                         if (!*fmt || !len)
3387                                 return num;
3388                         ++fmt;
3389
3390                         if (negate) {
3391                                 bitmap_complement(set, set, 256);
3392                                 /* exclude null '\0' byte */
3393                                 clear_bit(0, set);
3394                         }
3395
3396                         /* match must be non-empty */
3397                         if (!test_bit((u8)*str, set))
3398                                 return num;
3399
3400                         while (test_bit((u8)*str, set) && field_width--)
3401                                 *s++ = *str++;
3402                         *s = '\0';
3403                         ++num;
3404                 }
3405                 continue;
3406                 case 'o':
3407                         base = 8;
3408                         break;
3409                 case 'x':
3410                 case 'X':
3411                         base = 16;
3412                         break;
3413                 case 'i':
3414                         base = 0;
3415                         fallthrough;
3416                 case 'd':
3417                         is_sign = true;
3418                         fallthrough;
3419                 case 'u':
3420                         break;
3421                 case '%':
3422                         /* looking for '%' in str */
3423                         if (*str++ != '%')
3424                                 return num;
3425                         continue;
3426                 default:
3427                         /* invalid format; stop here */
3428                         return num;
3429                 }
3430
3431                 /* have some sort of integer conversion.
3432                  * first, skip white space in buffer.
3433                  */
3434                 str = skip_spaces(str);
3435
3436                 digit = *str;
3437                 if (is_sign && digit == '-')
3438                         digit = *(str + 1);
3439
3440                 if (!digit
3441                     || (base == 16 && !isxdigit(digit))
3442                     || (base == 10 && !isdigit(digit))
3443                     || (base == 8 && (!isdigit(digit) || digit > '7'))
3444                     || (base == 0 && !isdigit(digit)))
3445                         break;
3446
3447                 if (is_sign)
3448                         val.s = qualifier != 'L' ?
3449                                 simple_strtol(str, &next, base) :
3450                                 simple_strtoll(str, &next, base);
3451                 else
3452                         val.u = qualifier != 'L' ?
3453                                 simple_strtoul(str, &next, base) :
3454                                 simple_strtoull(str, &next, base);
3455
3456                 if (field_width > 0 && next - str > field_width) {
3457                         if (base == 0)
3458                                 _parse_integer_fixup_radix(str, &base);
3459                         while (next - str > field_width) {
3460                                 if (is_sign)
3461                                         val.s = div_s64(val.s, base);
3462                                 else
3463                                         val.u = div_u64(val.u, base);
3464                                 --next;
3465                         }
3466                 }
3467
3468                 switch (qualifier) {
3469                 case 'H':       /* that's 'hh' in format */
3470                         if (is_sign)
3471                                 *va_arg(args, signed char *) = val.s;
3472                         else
3473                                 *va_arg(args, unsigned char *) = val.u;
3474                         break;
3475                 case 'h':
3476                         if (is_sign)
3477                                 *va_arg(args, short *) = val.s;
3478                         else
3479                                 *va_arg(args, unsigned short *) = val.u;
3480                         break;
3481                 case 'l':
3482                         if (is_sign)
3483                                 *va_arg(args, long *) = val.s;
3484                         else
3485                                 *va_arg(args, unsigned long *) = val.u;
3486                         break;
3487                 case 'L':
3488                         if (is_sign)
3489                                 *va_arg(args, long long *) = val.s;
3490                         else
3491                                 *va_arg(args, unsigned long long *) = val.u;
3492                         break;
3493                 case 'z':
3494                         *va_arg(args, size_t *) = val.u;
3495                         break;
3496                 default:
3497                         if (is_sign)
3498                                 *va_arg(args, int *) = val.s;
3499                         else
3500                                 *va_arg(args, unsigned int *) = val.u;
3501                         break;
3502                 }
3503                 num++;
3504
3505                 if (!next)
3506                         break;
3507                 str = next;
3508         }
3509
3510         return num;
3511 }
3512 EXPORT_SYMBOL(vsscanf);
3513
3514 /**
3515  * sscanf - Unformat a buffer into a list of arguments
3516  * @buf:        input buffer
3517  * @fmt:        formatting of buffer
3518  * @...:        resulting arguments
3519  */
3520 int sscanf(const char *buf, const char *fmt, ...)
3521 {
3522         va_list args;
3523         int i;
3524
3525         va_start(args, fmt);
3526         i = vsscanf(buf, fmt, args);
3527         va_end(args);
3528
3529         return i;
3530 }
3531 EXPORT_SYMBOL(sscanf);