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