1// SPDX-License-Identifier: GPL-2.0-only 2/* 3 * Helpers for formatting and printing strings 4 * 5 * Copyright 31 August 2008 James Bottomley 6 * Copyright (C) 2013, Intel Corporation 7 */ 8#include <linux/bug.h> 9#include <linux/kernel.h> 10#include <linux/math64.h> 11#include <linux/export.h> 12#include <linux/ctype.h> 13#include <linux/device.h> 14#include <linux/errno.h> 15#include <linux/fs.h> 16#include <linux/limits.h> 17#include <linux/mm.h> 18#include <linux/slab.h> 19#include <linux/string.h> 20#include <linux/string_helpers.h> 21#include <kunit/test.h> 22#include <kunit/test-bug.h> 23 24/** 25 * string_get_size - get the size in the specified units 26 * @size: The size to be converted in blocks 27 * @blk_size: Size of the block (use 1 for size in bytes) 28 * @units: Units to use (powers of 1000 or 1024), whether to include space separator 29 * @buf: buffer to format to 30 * @len: length of buffer 31 * 32 * This function returns a string formatted to 3 significant figures 33 * giving the size in the required units. @buf should have room for 34 * at least 9 bytes and will always be zero terminated. 35 * 36 * Return value: number of characters of output that would have been written 37 * (which may be greater than len, if output was truncated). 38 */ 39int string_get_size(u64 size, u64 blk_size, const enum string_size_units units, 40 char *buf, int len) 41{ 42 enum string_size_units units_base = units & STRING_UNITS_MASK; 43 static const char *const units_10[] = { 44 "", "k", "M", "G", "T", "P", "E", "Z", "Y", 45 }; 46 static const char *const units_2[] = { 47 "", "Ki", "Mi", "Gi", "Ti", "Pi", "Ei", "Zi", "Yi", 48 }; 49 static const char *const *const units_str[] = { 50 [STRING_UNITS_10] = units_10, 51 [STRING_UNITS_2] = units_2, 52 }; 53 static const unsigned int divisor[] = { 54 [STRING_UNITS_10] = 1000, 55 [STRING_UNITS_2] = 1024, 56 }; 57 static const unsigned int rounding[] = { 500, 50, 5 }; 58 int i = 0, j; 59 u32 remainder = 0, sf_cap; 60 char tmp[8]; 61 const char *unit; 62 63 tmp[0] = '\0'; 64 65 if (blk_size == 0) 66 size = 0; 67 if (size == 0) 68 goto out; 69 70 /* This is Napier's algorithm. Reduce the original block size to 71 * 72 * coefficient * divisor[units_base]^i 73 * 74 * we do the reduction so both coefficients are just under 32 bits so 75 * that multiplying them together won't overflow 64 bits and we keep 76 * as much precision as possible in the numbers. 77 * 78 * Note: it's safe to throw away the remainders here because all the 79 * precision is in the coefficients. 80 */ 81 while (blk_size >> 32) { 82 do_div(blk_size, divisor[units_base]); 83 i++; 84 } 85 86 while (size >> 32) { 87 do_div(size, divisor[units_base]); 88 i++; 89 } 90 91 /* now perform the actual multiplication keeping i as the sum of the 92 * two logarithms */ 93 size *= blk_size; 94 95 /* and logarithmically reduce it until it's just under the divisor */ 96 while (size >= divisor[units_base]) { 97 remainder = do_div(size, divisor[units_base]); 98 i++; 99 } 100 101 /* work out in j how many digits of precision we need from the 102 * remainder */ 103 sf_cap = size; 104 for (j = 0; sf_cap*10 < 1000; j++) 105 sf_cap *= 10; 106 107 if (units_base == STRING_UNITS_2) { 108 /* express the remainder as a decimal. It's currently the 109 * numerator of a fraction whose denominator is 110 * divisor[units_base], which is 1 << 10 for STRING_UNITS_2 */ 111 remainder *= 1000; 112 remainder >>= 10; 113 } 114 115 /* add a 5 to the digit below what will be printed to ensure 116 * an arithmetical round up and carry it through to size */ 117 remainder += rounding[j]; 118 if (remainder >= 1000) { 119 remainder -= 1000; 120 size += 1; 121 } 122 123 if (j) { 124 snprintf(tmp, sizeof(tmp), ".%03u", remainder); 125 tmp[j+1] = '\0'; 126 } 127 128 out: 129 if (i >= ARRAY_SIZE(units_2)) 130 unit = "UNK"; 131 else 132 unit = units_str[units_base][i]; 133 134 return snprintf(buf, len, "%u%s%s%s%s", (u32)size, tmp, 135 (units & STRING_UNITS_NO_SPACE) ? "" : " ", 136 unit, 137 (units & STRING_UNITS_NO_BYTES) ? "" : "B"); 138} 139EXPORT_SYMBOL(string_get_size); 140 141/** 142 * parse_int_array_user - Split string into a sequence of integers 143 * @from: The user space buffer to read from 144 * @count: The maximum number of bytes to read 145 * @array: Returned pointer to sequence of integers 146 * 147 * On success @array is allocated and initialized with a sequence of 148 * integers extracted from the @from plus an additional element that 149 * begins the sequence and specifies the integers count. 150 * 151 * Caller takes responsibility for freeing @array when it is no longer 152 * needed. 153 */ 154int parse_int_array_user(const char __user *from, size_t count, int **array) 155{ 156 int *ints, nints; 157 char *buf; 158 int ret = 0; 159 160 buf = memdup_user_nul(from, count); 161 if (IS_ERR(buf)) 162 return PTR_ERR(buf); 163 164 get_options(buf, 0, &nints); 165 if (!nints) { 166 ret = -ENOENT; 167 goto free_buf; 168 } 169 170 ints = kcalloc(nints + 1, sizeof(*ints), GFP_KERNEL); 171 if (!ints) { 172 ret = -ENOMEM; 173 goto free_buf; 174 } 175 176 get_options(buf, nints + 1, ints); 177 *array = ints; 178 179free_buf: 180 kfree(buf); 181 return ret; 182} 183EXPORT_SYMBOL(parse_int_array_user); 184 185static bool unescape_space(char **src, char **dst) 186{ 187 char *p = *dst, *q = *src; 188 189 switch (*q) { 190 case 'n': 191 *p = '\n'; 192 break; 193 case 'r': 194 *p = '\r'; 195 break; 196 case 't': 197 *p = '\t'; 198 break; 199 case 'v': 200 *p = '\v'; 201 break; 202 case 'f': 203 *p = '\f'; 204 break; 205 default: 206 return false; 207 } 208 *dst += 1; 209 *src += 1; 210 return true; 211} 212 213static bool unescape_octal(char **src, char **dst) 214{ 215 char *p = *dst, *q = *src; 216 u8 num; 217 218 if (isodigit(*q) == 0) 219 return false; 220 221 num = (*q++) & 7; 222 while (num < 32 && isodigit(*q) && (q - *src < 3)) { 223 num <<= 3; 224 num += (*q++) & 7; 225 } 226 *p = num; 227 *dst += 1; 228 *src = q; 229 return true; 230} 231 232static bool unescape_hex(char **src, char **dst) 233{ 234 char *p = *dst, *q = *src; 235 int digit; 236 u8 num; 237 238 if (*q++ != 'x') 239 return false; 240 241 num = digit = hex_to_bin(*q++); 242 if (digit < 0) 243 return false; 244 245 digit = hex_to_bin(*q); 246 if (digit >= 0) { 247 q++; 248 num = (num << 4) | digit; 249 } 250 *p = num; 251 *dst += 1; 252 *src = q; 253 return true; 254} 255 256static bool unescape_special(char **src, char **dst) 257{ 258 char *p = *dst, *q = *src; 259 260 switch (*q) { 261 case '\"': 262 *p = '\"'; 263 break; 264 case '\\': 265 *p = '\\'; 266 break; 267 case 'a': 268 *p = '\a'; 269 break; 270 case 'e': 271 *p = '\e'; 272 break; 273 default: 274 return false; 275 } 276 *dst += 1; 277 *src += 1; 278 return true; 279} 280 281/** 282 * string_unescape - unquote characters in the given string 283 * @src: source buffer (escaped) 284 * @dst: destination buffer (unescaped) 285 * @size: size of the destination buffer (0 to unlimit) 286 * @flags: combination of the flags. 287 * 288 * Description: 289 * The function unquotes characters in the given string. 290 * 291 * Because the size of the output will be the same as or less than the size of 292 * the input, the transformation may be performed in place. 293 * 294 * Caller must provide valid source and destination pointers. Be aware that 295 * destination buffer will always be NULL-terminated. Source string must be 296 * NULL-terminated as well. The supported flags are:: 297 * 298 * UNESCAPE_SPACE: 299 * '\f' - form feed 300 * '\n' - new line 301 * '\r' - carriage return 302 * '\t' - horizontal tab 303 * '\v' - vertical tab 304 * UNESCAPE_OCTAL: 305 * '\NNN' - byte with octal value NNN (1 to 3 digits) 306 * UNESCAPE_HEX: 307 * '\xHH' - byte with hexadecimal value HH (1 to 2 digits) 308 * UNESCAPE_SPECIAL: 309 * '\"' - double quote 310 * '\\' - backslash 311 * '\a' - alert (BEL) 312 * '\e' - escape 313 * UNESCAPE_ANY: 314 * all previous together 315 * 316 * Return: 317 * The amount of the characters processed to the destination buffer excluding 318 * trailing '\0' is returned. 319 */ 320int string_unescape(char *src, char *dst, size_t size, unsigned int flags) 321{ 322 char *out = dst; 323 324 while (*src && --size) { 325 if (src[0] == '\\' && src[1] != '\0' && size > 1) { 326 src++; 327 size--; 328 329 if (flags & UNESCAPE_SPACE && 330 unescape_space(&src, &out)) 331 continue; 332 333 if (flags & UNESCAPE_OCTAL && 334 unescape_octal(&src, &out)) 335 continue; 336 337 if (flags & UNESCAPE_HEX && 338 unescape_hex(&src, &out)) 339 continue; 340 341 if (flags & UNESCAPE_SPECIAL && 342 unescape_special(&src, &out)) 343 continue; 344 345 *out++ = '\\'; 346 } 347 *out++ = *src++; 348 } 349 *out = '\0'; 350 351 return out - dst; 352} 353EXPORT_SYMBOL(string_unescape); 354 355static bool escape_passthrough(unsigned char c, char **dst, char *end) 356{ 357 char *out = *dst; 358 359 if (out < end) 360 *out = c; 361 *dst = out + 1; 362 return true; 363} 364 365static bool escape_space(unsigned char c, char **dst, char *end) 366{ 367 char *out = *dst; 368 unsigned char to; 369 370 switch (c) { 371 case '\n': 372 to = 'n'; 373 break; 374 case '\r': 375 to = 'r'; 376 break; 377 case '\t': 378 to = 't'; 379 break; 380 case '\v': 381 to = 'v'; 382 break; 383 case '\f': 384 to = 'f'; 385 break; 386 default: 387 return false; 388 } 389 390 if (out < end) 391 *out = '\\'; 392 ++out; 393 if (out < end) 394 *out = to; 395 ++out; 396 397 *dst = out; 398 return true; 399} 400 401static bool escape_special(unsigned char c, char **dst, char *end) 402{ 403 char *out = *dst; 404 unsigned char to; 405 406 switch (c) { 407 case '\\': 408 to = '\\'; 409 break; 410 case '\a': 411 to = 'a'; 412 break; 413 case '\e': 414 to = 'e'; 415 break; 416 case '"': 417 to = '"'; 418 break; 419 default: 420 return false; 421 } 422 423 if (out < end) 424 *out = '\\'; 425 ++out; 426 if (out < end) 427 *out = to; 428 ++out; 429 430 *dst = out; 431 return true; 432} 433 434static bool escape_null(unsigned char c, char **dst, char *end) 435{ 436 char *out = *dst; 437 438 if (c) 439 return false; 440 441 if (out < end) 442 *out = '\\'; 443 ++out; 444 if (out < end) 445 *out = '0'; 446 ++out; 447 448 *dst = out; 449 return true; 450} 451 452static bool escape_octal(unsigned char c, char **dst, char *end) 453{ 454 char *out = *dst; 455 456 if (out < end) 457 *out = '\\'; 458 ++out; 459 if (out < end) 460 *out = ((c >> 6) & 0x07) + '0'; 461 ++out; 462 if (out < end) 463 *out = ((c >> 3) & 0x07) + '0'; 464 ++out; 465 if (out < end) 466 *out = ((c >> 0) & 0x07) + '0'; 467 ++out; 468 469 *dst = out; 470 return true; 471} 472 473static bool escape_hex(unsigned char c, char **dst, char *end) 474{ 475 char *out = *dst; 476 477 if (out < end) 478 *out = '\\'; 479 ++out; 480 if (out < end) 481 *out = 'x'; 482 ++out; 483 if (out < end) 484 *out = hex_asc_hi(c); 485 ++out; 486 if (out < end) 487 *out = hex_asc_lo(c); 488 ++out; 489 490 *dst = out; 491 return true; 492} 493 494/** 495 * string_escape_mem - quote characters in the given memory buffer 496 * @src: source buffer (unescaped) 497 * @isz: source buffer size 498 * @dst: destination buffer (escaped) 499 * @osz: destination buffer size 500 * @flags: combination of the flags 501 * @only: NULL-terminated string containing characters used to limit 502 * the selected escape class. If characters are included in @only 503 * that would not normally be escaped by the classes selected 504 * in @flags, they will be copied to @dst unescaped. 505 * 506 * Description: 507 * The process of escaping byte buffer includes several parts. They are applied 508 * in the following sequence. 509 * 510 * 1. The character is not matched to the one from @only string and thus 511 * must go as-is to the output. 512 * 2. The character is matched to the printable and ASCII classes, if asked, 513 * and in case of match it passes through to the output. 514 * 3. The character is matched to the printable or ASCII class, if asked, 515 * and in case of match it passes through to the output. 516 * 4. The character is checked if it falls into the class given by @flags. 517 * %ESCAPE_OCTAL and %ESCAPE_HEX are going last since they cover any 518 * character. Note that they actually can't go together, otherwise 519 * %ESCAPE_HEX will be ignored. 520 * 521 * Caller must provide valid source and destination pointers. Be aware that 522 * destination buffer will not be NULL-terminated, thus caller have to append 523 * it if needs. The supported flags are:: 524 * 525 * %ESCAPE_SPACE: (special white space, not space itself) 526 * '\f' - form feed 527 * '\n' - new line 528 * '\r' - carriage return 529 * '\t' - horizontal tab 530 * '\v' - vertical tab 531 * %ESCAPE_SPECIAL: 532 * '\"' - double quote 533 * '\\' - backslash 534 * '\a' - alert (BEL) 535 * '\e' - escape 536 * %ESCAPE_NULL: 537 * '\0' - null 538 * %ESCAPE_OCTAL: 539 * '\NNN' - byte with octal value NNN (3 digits) 540 * %ESCAPE_ANY: 541 * all previous together 542 * %ESCAPE_NP: 543 * escape only non-printable characters, checked by isprint() 544 * %ESCAPE_ANY_NP: 545 * all previous together 546 * %ESCAPE_HEX: 547 * '\xHH' - byte with hexadecimal value HH (2 digits) 548 * %ESCAPE_NA: 549 * escape only non-ascii characters, checked by isascii() 550 * %ESCAPE_NAP: 551 * escape only non-printable or non-ascii characters 552 * %ESCAPE_APPEND: 553 * append characters from @only to be escaped by the given classes 554 * 555 * %ESCAPE_APPEND would help to pass additional characters to the escaped, when 556 * one of %ESCAPE_NP, %ESCAPE_NA, or %ESCAPE_NAP is provided. 557 * 558 * One notable caveat, the %ESCAPE_NAP, %ESCAPE_NP and %ESCAPE_NA have the 559 * higher priority than the rest of the flags (%ESCAPE_NAP is the highest). 560 * It doesn't make much sense to use either of them without %ESCAPE_OCTAL 561 * or %ESCAPE_HEX, because they cover most of the other character classes. 562 * %ESCAPE_NAP can utilize %ESCAPE_SPACE or %ESCAPE_SPECIAL in addition to 563 * the above. 564 * 565 * Return: 566 * The total size of the escaped output that would be generated for 567 * the given input and flags. To check whether the output was 568 * truncated, compare the return value to osz. There is room left in 569 * dst for a '\0' terminator if and only if ret < osz. 570 */ 571int string_escape_mem(const char *src, size_t isz, char *dst, size_t osz, 572 unsigned int flags, const char *only) 573{ 574 char *p = dst; 575 char *end = p + osz; 576 bool is_dict = only && *only; 577 bool is_append = flags & ESCAPE_APPEND; 578 579 while (isz--) { 580 unsigned char c = *src++; 581 bool in_dict = is_dict && strchr(only, c); 582 583 /* 584 * Apply rules in the following sequence: 585 * - the @only string is supplied and does not contain a 586 * character under question 587 * - the character is printable and ASCII, when @flags has 588 * %ESCAPE_NAP bit set 589 * - the character is printable, when @flags has 590 * %ESCAPE_NP bit set 591 * - the character is ASCII, when @flags has 592 * %ESCAPE_NA bit set 593 * - the character doesn't fall into a class of symbols 594 * defined by given @flags 595 * In these cases we just pass through a character to the 596 * output buffer. 597 * 598 * When %ESCAPE_APPEND is passed, the characters from @only 599 * have been excluded from the %ESCAPE_NAP, %ESCAPE_NP, and 600 * %ESCAPE_NA cases. 601 */ 602 if (!(is_append || in_dict) && is_dict && 603 escape_passthrough(c, &p, end)) 604 continue; 605 606 if (!(is_append && in_dict) && isascii(c) && isprint(c) && 607 flags & ESCAPE_NAP && escape_passthrough(c, &p, end)) 608 continue; 609 610 if (!(is_append && in_dict) && isprint(c) && 611 flags & ESCAPE_NP && escape_passthrough(c, &p, end)) 612 continue; 613 614 if (!(is_append && in_dict) && isascii(c) && 615 flags & ESCAPE_NA && escape_passthrough(c, &p, end)) 616 continue; 617 618 if (flags & ESCAPE_SPACE && escape_space(c, &p, end)) 619 continue; 620 621 if (flags & ESCAPE_SPECIAL && escape_special(c, &p, end)) 622 continue; 623 624 if (flags & ESCAPE_NULL && escape_null(c, &p, end)) 625 continue; 626 627 /* ESCAPE_OCTAL and ESCAPE_HEX always go last */ 628 if (flags & ESCAPE_OCTAL && escape_octal(c, &p, end)) 629 continue; 630 631 if (flags & ESCAPE_HEX && escape_hex(c, &p, end)) 632 continue; 633 634 escape_passthrough(c, &p, end); 635 } 636 637 return p - dst; 638} 639EXPORT_SYMBOL(string_escape_mem); 640 641/* 642 * Return an allocated string that has been escaped of special characters 643 * and double quotes, making it safe to log in quotes. 644 */ 645char *kstrdup_quotable(const char *src, gfp_t gfp) 646{ 647 size_t slen, dlen; 648 char *dst; 649 const int flags = ESCAPE_HEX; 650 const char esc[] = "\f\n\r\t\v\a\e\\\""; 651 652 if (!src) 653 return NULL; 654 slen = strlen(src); 655 656 dlen = string_escape_mem(src, slen, NULL, 0, flags, esc); 657 dst = kmalloc(dlen + 1, gfp); 658 if (!dst) 659 return NULL; 660 661 WARN_ON(string_escape_mem(src, slen, dst, dlen, flags, esc) != dlen); 662 dst[dlen] = '\0'; 663 664 return dst; 665} 666EXPORT_SYMBOL_GPL(kstrdup_quotable); 667 668/* 669 * Returns allocated NULL-terminated string containing process 670 * command line, with inter-argument NULLs replaced with spaces, 671 * and other special characters escaped. 672 */ 673char *kstrdup_quotable_cmdline(struct task_struct *task, gfp_t gfp) 674{ 675 char *buffer, *quoted; 676 int i, res; 677 678 buffer = kmalloc(PAGE_SIZE, GFP_KERNEL); 679 if (!buffer) 680 return NULL; 681 682 res = get_cmdline(task, buffer, PAGE_SIZE - 1); 683 buffer[res] = '\0'; 684 685 /* Collapse trailing NULLs, leave res pointing to last non-NULL. */ 686 while (--res >= 0 && buffer[res] == '\0') 687 ; 688 689 /* Replace inter-argument NULLs. */ 690 for (i = 0; i <= res; i++) 691 if (buffer[i] == '\0') 692 buffer[i] = ' '; 693 694 /* Make sure result is printable. */ 695 quoted = kstrdup_quotable(buffer, gfp); 696 kfree(buffer); 697 return quoted; 698} 699EXPORT_SYMBOL_GPL(kstrdup_quotable_cmdline); 700 701/* 702 * Returns allocated NULL-terminated string containing pathname, 703 * with special characters escaped, able to be safely logged. If 704 * there is an error, the leading character will be "<". 705 */ 706char *kstrdup_quotable_file(struct file *file, gfp_t gfp) 707{ 708 char *temp, *pathname; 709 710 if (!file) 711 return kstrdup("<unknown>", gfp); 712 713 /* We add 11 spaces for ' (deleted)' to be appended */ 714 temp = kmalloc(PATH_MAX + 11, GFP_KERNEL); 715 if (!temp) 716 return kstrdup("<no_memory>", gfp); 717 718 pathname = file_path(file, temp, PATH_MAX + 11); 719 if (IS_ERR(pathname)) 720 pathname = kstrdup("<too_long>", gfp); 721 else 722 pathname = kstrdup_quotable(pathname, gfp); 723 724 kfree(temp); 725 return pathname; 726} 727EXPORT_SYMBOL_GPL(kstrdup_quotable_file); 728 729/* 730 * Returns duplicate string in which the @old characters are replaced by @new. 731 */ 732char *kstrdup_and_replace(const char *src, char old, char new, gfp_t gfp) 733{ 734 char *dst; 735 736 dst = kstrdup(src, gfp); 737 if (!dst) 738 return NULL; 739 740 return strreplace(dst, old, new); 741} 742EXPORT_SYMBOL_GPL(kstrdup_and_replace); 743 744/** 745 * kasprintf_strarray - allocate and fill array of sequential strings 746 * @gfp: flags for the slab allocator 747 * @prefix: prefix to be used 748 * @n: amount of lines to be allocated and filled 749 * 750 * Allocates and fills @n strings using pattern "%s-%zu", where prefix 751 * is provided by caller. The caller is responsible to free them with 752 * kfree_strarray() after use. 753 * 754 * Returns array of strings or NULL when memory can't be allocated. 755 */ 756char **kasprintf_strarray(gfp_t gfp, const char *prefix, size_t n) 757{ 758 char **names; 759 size_t i; 760 761 names = kcalloc(n + 1, sizeof(char *), gfp); 762 if (!names) 763 return NULL; 764 765 for (i = 0; i < n; i++) { 766 names[i] = kasprintf(gfp, "%s-%zu", prefix, i); 767 if (!names[i]) { 768 kfree_strarray(names, i); 769 return NULL; 770 } 771 } 772 773 return names; 774} 775EXPORT_SYMBOL_GPL(kasprintf_strarray); 776 777/** 778 * kfree_strarray - free a number of dynamically allocated strings contained 779 * in an array and the array itself 780 * 781 * @array: Dynamically allocated array of strings to free. 782 * @n: Number of strings (starting from the beginning of the array) to free. 783 * 784 * Passing a non-NULL @array and @n == 0 as well as NULL @array are valid 785 * use-cases. If @array is NULL, the function does nothing. 786 */ 787void kfree_strarray(char **array, size_t n) 788{ 789 unsigned int i; 790 791 if (!array) 792 return; 793 794 for (i = 0; i < n; i++) 795 kfree(array[i]); 796 kfree(array); 797} 798EXPORT_SYMBOL_GPL(kfree_strarray); 799 800struct strarray { 801 char **array; 802 size_t n; 803}; 804 805static void devm_kfree_strarray(struct device *dev, void *res) 806{ 807 struct strarray *array = res; 808 809 kfree_strarray(array->array, array->n); 810} 811 812char **devm_kasprintf_strarray(struct device *dev, const char *prefix, size_t n) 813{ 814 struct strarray *ptr; 815 816 ptr = devres_alloc(devm_kfree_strarray, sizeof(*ptr), GFP_KERNEL); 817 if (!ptr) 818 return ERR_PTR(-ENOMEM); 819 820 ptr->array = kasprintf_strarray(GFP_KERNEL, prefix, n); 821 if (!ptr->array) { 822 devres_free(ptr); 823 return ERR_PTR(-ENOMEM); 824 } 825 826 ptr->n = n; 827 devres_add(dev, ptr); 828 829 return ptr->array; 830} 831EXPORT_SYMBOL_GPL(devm_kasprintf_strarray); 832 833/** 834 * skip_spaces - Removes leading whitespace from @str. 835 * @str: The string to be stripped. 836 * 837 * Returns a pointer to the first non-whitespace character in @str. 838 */ 839char *skip_spaces(const char *str) 840{ 841 while (isspace(*str)) 842 ++str; 843 return (char *)str; 844} 845EXPORT_SYMBOL(skip_spaces); 846 847/** 848 * strim - Removes leading and trailing whitespace from @s. 849 * @s: The string to be stripped. 850 * 851 * Note that the first trailing whitespace is replaced with a %NUL-terminator 852 * in the given string @s. Returns a pointer to the first non-whitespace 853 * character in @s. 854 */ 855char *strim(char *s) 856{ 857 size_t size; 858 char *end; 859 860 size = strlen(s); 861 if (!size) 862 return s; 863 864 end = s + size - 1; 865 while (end >= s && isspace(*end)) 866 end--; 867 *(end + 1) = '\0'; 868 869 return skip_spaces(s); 870} 871EXPORT_SYMBOL(strim); 872 873/** 874 * sysfs_streq - return true if strings are equal, modulo trailing newline 875 * @s1: one string 876 * @s2: another string 877 * 878 * This routine returns true iff two strings are equal, treating both 879 * NUL and newline-then-NUL as equivalent string terminations. It's 880 * geared for use with sysfs input strings, which generally terminate 881 * with newlines but are compared against values without newlines. 882 */ 883bool sysfs_streq(const char *s1, const char *s2) 884{ 885 while (*s1 && *s1 == *s2) { 886 s1++; 887 s2++; 888 } 889 890 if (*s1 == *s2) 891 return true; 892 if (!*s1 && *s2 == '\n' && !s2[1]) 893 return true; 894 if (*s1 == '\n' && !s1[1] && !*s2) 895 return true; 896 return false; 897} 898EXPORT_SYMBOL(sysfs_streq); 899 900/** 901 * match_string - matches given string in an array 902 * @array: array of strings 903 * @n: number of strings in the array or -1 for NULL terminated arrays 904 * @string: string to match with 905 * 906 * This routine will look for a string in an array of strings up to the 907 * n-th element in the array or until the first NULL element. 908 * 909 * Historically the value of -1 for @n, was used to search in arrays that 910 * are NULL terminated. However, the function does not make a distinction 911 * when finishing the search: either @n elements have been compared OR 912 * the first NULL element was found. 913 * 914 * Return: 915 * index of a @string in the @array if matches, or %-EINVAL otherwise. 916 */ 917int match_string(const char * const *array, size_t n, const char *string) 918{ 919 int index; 920 const char *item; 921 922 for (index = 0; index < n; index++) { 923 item = array[index]; 924 if (!item) 925 break; 926 if (!strcmp(item, string)) 927 return index; 928 } 929 930 return -EINVAL; 931} 932EXPORT_SYMBOL(match_string); 933 934/** 935 * __sysfs_match_string - matches given string in an array 936 * @array: array of strings 937 * @n: number of strings in the array or -1 for NULL terminated arrays 938 * @str: string to match with 939 * 940 * Returns index of @str in the @array or -EINVAL, just like match_string(). 941 * Uses sysfs_streq instead of strcmp for matching. 942 * 943 * This routine will look for a string in an array of strings up to the 944 * n-th element in the array or until the first NULL element. 945 * 946 * Historically the value of -1 for @n, was used to search in arrays that 947 * are NULL terminated. However, the function does not make a distinction 948 * when finishing the search: either @n elements have been compared OR 949 * the first NULL element was found. 950 */ 951int __sysfs_match_string(const char * const *array, size_t n, const char *str) 952{ 953 const char *item; 954 int index; 955 956 for (index = 0; index < n; index++) { 957 item = array[index]; 958 if (!item) 959 break; 960 if (sysfs_streq(item, str)) 961 return index; 962 } 963 964 return -EINVAL; 965} 966EXPORT_SYMBOL(__sysfs_match_string); 967 968/** 969 * strreplace - Replace all occurrences of character in string. 970 * @str: The string to operate on. 971 * @old: The character being replaced. 972 * @new: The character @old is replaced with. 973 * 974 * Replaces the each @old character with a @new one in the given string @str. 975 * 976 * Return: pointer to the string @str itself. 977 */ 978char *strreplace(char *str, char old, char new) 979{ 980 char *s = str; 981 982 for (; *s; ++s) 983 if (*s == old) 984 *s = new; 985 return str; 986} 987EXPORT_SYMBOL(strreplace); 988 989/** 990 * memcpy_and_pad - Copy one buffer to another with padding 991 * @dest: Where to copy to 992 * @dest_len: The destination buffer size 993 * @src: Where to copy from 994 * @count: The number of bytes to copy 995 * @pad: Character to use for padding if space is left in destination. 996 */ 997void memcpy_and_pad(void *dest, size_t dest_len, const void *src, size_t count, 998 int pad) 999{ 1000 if (dest_len > count) { 1001 memcpy(dest, src, count); 1002 memset(dest + count, pad, dest_len - count); 1003 } else { 1004 memcpy(dest, src, dest_len); 1005 } 1006} 1007EXPORT_SYMBOL(memcpy_and_pad); 1008 1009#ifdef CONFIG_FORTIFY_SOURCE 1010/* These are placeholders for fortify compile-time warnings. */ 1011void __read_overflow2_field(size_t avail, size_t wanted) { } 1012EXPORT_SYMBOL(__read_overflow2_field); 1013void __write_overflow_field(size_t avail, size_t wanted) { } 1014EXPORT_SYMBOL(__write_overflow_field); 1015 1016static const char * const fortify_func_name[] = { 1017#define MAKE_FORTIFY_FUNC_NAME(func) [MAKE_FORTIFY_FUNC(func)] = #func 1018 EACH_FORTIFY_FUNC(MAKE_FORTIFY_FUNC_NAME) 1019#undef MAKE_FORTIFY_FUNC_NAME 1020}; 1021 1022void __fortify_report(const u8 reason, const size_t avail, const size_t size) 1023{ 1024 const u8 func = FORTIFY_REASON_FUNC(reason); 1025 const bool write = FORTIFY_REASON_DIR(reason); 1026 const char *name; 1027 1028 name = fortify_func_name[umin(func, FORTIFY_FUNC_UNKNOWN)]; 1029 WARN(1, "%s: detected buffer overflow: %zu byte %s of buffer size %zu\n", 1030 name, size, str_read_write(!write), avail); 1031} 1032EXPORT_SYMBOL(__fortify_report); 1033 1034void __fortify_panic(const u8 reason, const size_t avail, const size_t size) 1035{ 1036 __fortify_report(reason, avail, size); 1037 BUG(); 1038} 1039EXPORT_SYMBOL(__fortify_panic); 1040#endif /* CONFIG_FORTIFY_SOURCE */ 1041