projects/linux·blob v5.16-rc5 · refs

913 lines · 21.3 KiB

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/errno.h>
14#include <linux/fs.h>
15#include <linux/limits.h>
16#include <linux/mm.h>
17#include <linux/slab.h>
18#include <linux/string.h>
19#include <linux/string_helpers.h>
20
21/**
22 * string_get_size - get the size in the specified units
23 * @size: The size to be converted in blocks
24 * @blk_size: Size of the block (use 1 for size in bytes)
25 * @units: units to use (powers of 1000 or 1024)
26 * @buf: buffer to format to
27 * @len: length of buffer
28 *
29 * This function returns a string formatted to 3 significant figures
30 * giving the size in the required units. @buf should have room for
31 * at least 9 bytes and will always be zero terminated.
32 *
33 */
34void string_get_size(u64 size, u64 blk_size, const enum string_size_units units,
35 char *buf, int len)
36{
37 static const char *const units_10[] = {
38 "B", "kB", "MB", "GB", "TB", "PB", "EB", "ZB", "YB"
39 };
40 static const char *const units_2[] = {
41 "B", "KiB", "MiB", "GiB", "TiB", "PiB", "EiB", "ZiB", "YiB"
42 };
43 static const char *const *const units_str[] = {
44 [STRING_UNITS_10] = units_10,
45 [STRING_UNITS_2] = units_2,
46 };
47 static const unsigned int divisor[] = {
48 [STRING_UNITS_10] = 1000,
49 [STRING_UNITS_2] = 1024,
50 };
51 static const unsigned int rounding[] = { 500, 50, 5 };
52 int i = 0, j;
53 u32 remainder = 0, sf_cap;
54 char tmp[8];
55 const char *unit;
56
57 tmp[0] = '\0';
58
59 if (blk_size == 0)
60 size = 0;
61 if (size == 0)
62 goto out;
63
64 /* This is Napier's algorithm. Reduce the original block size to
65 *
66 * coefficient * divisor[units]^i
67 *
68 * we do the reduction so both coefficients are just under 32 bits so
69 * that multiplying them together won't overflow 64 bits and we keep
70 * as much precision as possible in the numbers.
71 *
72 * Note: it's safe to throw away the remainders here because all the
73 * precision is in the coefficients.
74 */
75 while (blk_size >> 32) {
76 do_div(blk_size, divisor[units]);
77 i++;
78 }
79
80 while (size >> 32) {
81 do_div(size, divisor[units]);
82 i++;
83 }
84
85 /* now perform the actual multiplication keeping i as the sum of the
86 * two logarithms */
87 size *= blk_size;
88
89 /* and logarithmically reduce it until it's just under the divisor */
90 while (size >= divisor[units]) {
91 remainder = do_div(size, divisor[units]);
92 i++;
93 }
94
95 /* work out in j how many digits of precision we need from the
96 * remainder */
97 sf_cap = size;
98 for (j = 0; sf_cap*10 < 1000; j++)
99 sf_cap *= 10;
100
101 if (units == STRING_UNITS_2) {
102 /* express the remainder as a decimal. It's currently the
103 * numerator of a fraction whose denominator is
104 * divisor[units], which is 1 << 10 for STRING_UNITS_2 */
105 remainder *= 1000;
106 remainder >>= 10;
107 }
108
109 /* add a 5 to the digit below what will be printed to ensure
110 * an arithmetical round up and carry it through to size */
111 remainder += rounding[j];
112 if (remainder >= 1000) {
113 remainder -= 1000;
114 size += 1;
115 }
116
117 if (j) {
118 snprintf(tmp, sizeof(tmp), ".%03u", remainder);
119 tmp[j+1] = '\0';
120 }
121
122 out:
123 if (i >= ARRAY_SIZE(units_2))
124 unit = "UNK";
125 else
126 unit = units_str[units][i];
127
128 snprintf(buf, len, "%u%s %s", (u32)size,
129 tmp, unit);
130}
131EXPORT_SYMBOL(string_get_size);
132
133static bool unescape_space(char **src, char **dst)
134{
135 char *p = *dst, *q = *src;
136
137 switch (*q) {
138 case 'n':
139 *p = '\n';
140 break;
141 case 'r':
142 *p = '\r';
143 break;
144 case 't':
145 *p = '\t';
146 break;
147 case 'v':
148 *p = '\v';
149 break;
150 case 'f':
151 *p = '\f';
152 break;
153 default:
154 return false;
155 }
156 *dst += 1;
157 *src += 1;
158 return true;
159}
160
161static bool unescape_octal(char **src, char **dst)
162{
163 char *p = *dst, *q = *src;
164 u8 num;
165
166 if (isodigit(*q) == 0)
167 return false;
168
169 num = (*q++) & 7;
170 while (num < 32 && isodigit(*q) && (q - *src < 3)) {
171 num <<= 3;
172 num += (*q++) & 7;
173 }
174 *p = num;
175 *dst += 1;
176 *src = q;
177 return true;
178}
179
180static bool unescape_hex(char **src, char **dst)
181{
182 char *p = *dst, *q = *src;
183 int digit;
184 u8 num;
185
186 if (*q++ != 'x')
187 return false;
188
189 num = digit = hex_to_bin(*q++);
190 if (digit < 0)
191 return false;
192
193 digit = hex_to_bin(*q);
194 if (digit >= 0) {
195 q++;
196 num = (num << 4) | digit;
197 }
198 *p = num;
199 *dst += 1;
200 *src = q;
201 return true;
202}
203
204static bool unescape_special(char **src, char **dst)
205{
206 char *p = *dst, *q = *src;
207
208 switch (*q) {
209 case '\"':
210 *p = '\"';
211 break;
212 case '\\':
213 *p = '\\';
214 break;
215 case 'a':
216 *p = '\a';
217 break;
218 case 'e':
219 *p = '\e';
220 break;
221 default:
222 return false;
223 }
224 *dst += 1;
225 *src += 1;
226 return true;
227}
228
229/**
230 * string_unescape - unquote characters in the given string
231 * @src: source buffer (escaped)
232 * @dst: destination buffer (unescaped)
233 * @size: size of the destination buffer (0 to unlimit)
234 * @flags: combination of the flags.
235 *
236 * Description:
237 * The function unquotes characters in the given string.
238 *
239 * Because the size of the output will be the same as or less than the size of
240 * the input, the transformation may be performed in place.
241 *
242 * Caller must provide valid source and destination pointers. Be aware that
243 * destination buffer will always be NULL-terminated. Source string must be
244 * NULL-terminated as well. The supported flags are::
245 *
246 * UNESCAPE_SPACE:
247 * '\f' - form feed
248 * '\n' - new line
249 * '\r' - carriage return
250 * '\t' - horizontal tab
251 * '\v' - vertical tab
252 * UNESCAPE_OCTAL:
253 * '\NNN' - byte with octal value NNN (1 to 3 digits)
254 * UNESCAPE_HEX:
255 * '\xHH' - byte with hexadecimal value HH (1 to 2 digits)
256 * UNESCAPE_SPECIAL:
257 * '\"' - double quote
258 * '\\' - backslash
259 * '\a' - alert (BEL)
260 * '\e' - escape
261 * UNESCAPE_ANY:
262 * all previous together
263 *
264 * Return:
265 * The amount of the characters processed to the destination buffer excluding
266 * trailing '\0' is returned.
267 */
268int string_unescape(char *src, char *dst, size_t size, unsigned int flags)
269{
270 char *out = dst;
271
272 while (*src && --size) {
273 if (src[0] == '\\' && src[1] != '\0' && size > 1) {
274 src++;
275 size--;
276
277 if (flags & UNESCAPE_SPACE &&
278 unescape_space(&src, &out))
279 continue;
280
281 if (flags & UNESCAPE_OCTAL &&
282 unescape_octal(&src, &out))
283 continue;
284
285 if (flags & UNESCAPE_HEX &&
286 unescape_hex(&src, &out))
287 continue;
288
289 if (flags & UNESCAPE_SPECIAL &&
290 unescape_special(&src, &out))
291 continue;
292
293 *out++ = '\\';
294 }
295 *out++ = *src++;
296 }
297 *out = '\0';
298
299 return out - dst;
300}
301EXPORT_SYMBOL(string_unescape);
302
303static bool escape_passthrough(unsigned char c, char **dst, char *end)
304{
305 char *out = *dst;
306
307 if (out < end)
308 *out = c;
309 *dst = out + 1;
310 return true;
311}
312
313static bool escape_space(unsigned char c, char **dst, char *end)
314{
315 char *out = *dst;
316 unsigned char to;
317
318 switch (c) {
319 case '\n':
320 to = 'n';
321 break;
322 case '\r':
323 to = 'r';
324 break;
325 case '\t':
326 to = 't';
327 break;
328 case '\v':
329 to = 'v';
330 break;
331 case '\f':
332 to = 'f';
333 break;
334 default:
335 return false;
336 }
337
338 if (out < end)
339 *out = '\\';
340 ++out;
341 if (out < end)
342 *out = to;
343 ++out;
344
345 *dst = out;
346 return true;
347}
348
349static bool escape_special(unsigned char c, char **dst, char *end)
350{
351 char *out = *dst;
352 unsigned char to;
353
354 switch (c) {
355 case '\\':
356 to = '\\';
357 break;
358 case '\a':
359 to = 'a';
360 break;
361 case '\e':
362 to = 'e';
363 break;
364 case '"':
365 to = '"';
366 break;
367 default:
368 return false;
369 }
370
371 if (out < end)
372 *out = '\\';
373 ++out;
374 if (out < end)
375 *out = to;
376 ++out;
377
378 *dst = out;
379 return true;
380}
381
382static bool escape_null(unsigned char c, char **dst, char *end)
383{
384 char *out = *dst;
385
386 if (c)
387 return false;
388
389 if (out < end)
390 *out = '\\';
391 ++out;
392 if (out < end)
393 *out = '0';
394 ++out;
395
396 *dst = out;
397 return true;
398}
399
400static bool escape_octal(unsigned char c, char **dst, char *end)
401{
402 char *out = *dst;
403
404 if (out < end)
405 *out = '\\';
406 ++out;
407 if (out < end)
408 *out = ((c >> 6) & 0x07) + '0';
409 ++out;
410 if (out < end)
411 *out = ((c >> 3) & 0x07) + '0';
412 ++out;
413 if (out < end)
414 *out = ((c >> 0) & 0x07) + '0';
415 ++out;
416
417 *dst = out;
418 return true;
419}
420
421static bool escape_hex(unsigned char c, char **dst, char *end)
422{
423 char *out = *dst;
424
425 if (out < end)
426 *out = '\\';
427 ++out;
428 if (out < end)
429 *out = 'x';
430 ++out;
431 if (out < end)
432 *out = hex_asc_hi(c);
433 ++out;
434 if (out < end)
435 *out = hex_asc_lo(c);
436 ++out;
437
438 *dst = out;
439 return true;
440}
441
442/**
443 * string_escape_mem - quote characters in the given memory buffer
444 * @src: source buffer (unescaped)
445 * @isz: source buffer size
446 * @dst: destination buffer (escaped)
447 * @osz: destination buffer size
448 * @flags: combination of the flags
449 * @only: NULL-terminated string containing characters used to limit
450 * the selected escape class. If characters are included in @only
451 * that would not normally be escaped by the classes selected
452 * in @flags, they will be copied to @dst unescaped.
453 *
454 * Description:
455 * The process of escaping byte buffer includes several parts. They are applied
456 * in the following sequence.
457 *
458 * 1. The character is not matched to the one from @only string and thus
459 * must go as-is to the output.
460 * 2. The character is matched to the printable and ASCII classes, if asked,
461 * and in case of match it passes through to the output.
462 * 3. The character is matched to the printable or ASCII class, if asked,
463 * and in case of match it passes through to the output.
464 * 4. The character is checked if it falls into the class given by @flags.
465 * %ESCAPE_OCTAL and %ESCAPE_HEX are going last since they cover any
466 * character. Note that they actually can't go together, otherwise
467 * %ESCAPE_HEX will be ignored.
468 *
469 * Caller must provide valid source and destination pointers. Be aware that
470 * destination buffer will not be NULL-terminated, thus caller have to append
471 * it if needs. The supported flags are::
472 *
473 * %ESCAPE_SPACE: (special white space, not space itself)
474 * '\f' - form feed
475 * '\n' - new line
476 * '\r' - carriage return
477 * '\t' - horizontal tab
478 * '\v' - vertical tab
479 * %ESCAPE_SPECIAL:
480 * '\"' - double quote
481 * '\\' - backslash
482 * '\a' - alert (BEL)
483 * '\e' - escape
484 * %ESCAPE_NULL:
485 * '\0' - null
486 * %ESCAPE_OCTAL:
487 * '\NNN' - byte with octal value NNN (3 digits)
488 * %ESCAPE_ANY:
489 * all previous together
490 * %ESCAPE_NP:
491 * escape only non-printable characters, checked by isprint()
492 * %ESCAPE_ANY_NP:
493 * all previous together
494 * %ESCAPE_HEX:
495 * '\xHH' - byte with hexadecimal value HH (2 digits)
496 * %ESCAPE_NA:
497 * escape only non-ascii characters, checked by isascii()
498 * %ESCAPE_NAP:
499 * escape only non-printable or non-ascii characters
500 * %ESCAPE_APPEND:
501 * append characters from @only to be escaped by the given classes
502 *
503 * %ESCAPE_APPEND would help to pass additional characters to the escaped, when
504 * one of %ESCAPE_NP, %ESCAPE_NA, or %ESCAPE_NAP is provided.
505 *
506 * One notable caveat, the %ESCAPE_NAP, %ESCAPE_NP and %ESCAPE_NA have the
507 * higher priority than the rest of the flags (%ESCAPE_NAP is the highest).
508 * It doesn't make much sense to use either of them without %ESCAPE_OCTAL
509 * or %ESCAPE_HEX, because they cover most of the other character classes.
510 * %ESCAPE_NAP can utilize %ESCAPE_SPACE or %ESCAPE_SPECIAL in addition to
511 * the above.
512 *
513 * Return:
514 * The total size of the escaped output that would be generated for
515 * the given input and flags. To check whether the output was
516 * truncated, compare the return value to osz. There is room left in
517 * dst for a '\0' terminator if and only if ret < osz.
518 */
519int string_escape_mem(const char *src, size_t isz, char *dst, size_t osz,
520 unsigned int flags, const char *only)
521{
522 char *p = dst;
523 char *end = p + osz;
524 bool is_dict = only && *only;
525 bool is_append = flags & ESCAPE_APPEND;
526
527 while (isz--) {
528 unsigned char c = *src++;
529 bool in_dict = is_dict && strchr(only, c);
530
531 /*
532 * Apply rules in the following sequence:
533 * - the @only string is supplied and does not contain a
534 * character under question
535 * - the character is printable and ASCII, when @flags has
536 * %ESCAPE_NAP bit set
537 * - the character is printable, when @flags has
538 * %ESCAPE_NP bit set
539 * - the character is ASCII, when @flags has
540 * %ESCAPE_NA bit set
541 * - the character doesn't fall into a class of symbols
542 * defined by given @flags
543 * In these cases we just pass through a character to the
544 * output buffer.
545 *
546 * When %ESCAPE_APPEND is passed, the characters from @only
547 * have been excluded from the %ESCAPE_NAP, %ESCAPE_NP, and
548 * %ESCAPE_NA cases.
549 */
550 if (!(is_append || in_dict) && is_dict &&
551 escape_passthrough(c, &p, end))
552 continue;
553
554 if (!(is_append && in_dict) && isascii(c) && isprint(c) &&
555 flags & ESCAPE_NAP && escape_passthrough(c, &p, end))
556 continue;
557
558 if (!(is_append && in_dict) && isprint(c) &&
559 flags & ESCAPE_NP && escape_passthrough(c, &p, end))
560 continue;
561
562 if (!(is_append && in_dict) && isascii(c) &&
563 flags & ESCAPE_NA && escape_passthrough(c, &p, end))
564 continue;
565
566 if (flags & ESCAPE_SPACE && escape_space(c, &p, end))
567 continue;
568
569 if (flags & ESCAPE_SPECIAL && escape_special(c, &p, end))
570 continue;
571
572 if (flags & ESCAPE_NULL && escape_null(c, &p, end))
573 continue;
574
575 /* ESCAPE_OCTAL and ESCAPE_HEX always go last */
576 if (flags & ESCAPE_OCTAL && escape_octal(c, &p, end))
577 continue;
578
579 if (flags & ESCAPE_HEX && escape_hex(c, &p, end))
580 continue;
581
582 escape_passthrough(c, &p, end);
583 }
584
585 return p - dst;
586}
587EXPORT_SYMBOL(string_escape_mem);
588
589/*
590 * Return an allocated string that has been escaped of special characters
591 * and double quotes, making it safe to log in quotes.
592 */
593char *kstrdup_quotable(const char *src, gfp_t gfp)
594{
595 size_t slen, dlen;
596 char *dst;
597 const int flags = ESCAPE_HEX;
598 const char esc[] = "\f\n\r\t\v\a\e\\\"";
599
600 if (!src)
601 return NULL;
602 slen = strlen(src);
603
604 dlen = string_escape_mem(src, slen, NULL, 0, flags, esc);
605 dst = kmalloc(dlen + 1, gfp);
606 if (!dst)
607 return NULL;
608
609 WARN_ON(string_escape_mem(src, slen, dst, dlen, flags, esc) != dlen);
610 dst[dlen] = '\0';
611
612 return dst;
613}
614EXPORT_SYMBOL_GPL(kstrdup_quotable);
615
616/*
617 * Returns allocated NULL-terminated string containing process
618 * command line, with inter-argument NULLs replaced with spaces,
619 * and other special characters escaped.
620 */
621char *kstrdup_quotable_cmdline(struct task_struct *task, gfp_t gfp)
622{
623 char *buffer, *quoted;
624 int i, res;
625
626 buffer = kmalloc(PAGE_SIZE, GFP_KERNEL);
627 if (!buffer)
628 return NULL;
629
630 res = get_cmdline(task, buffer, PAGE_SIZE - 1);
631 buffer[res] = '\0';
632
633 /* Collapse trailing NULLs, leave res pointing to last non-NULL. */
634 while (--res >= 0 && buffer[res] == '\0')
635 ;
636
637 /* Replace inter-argument NULLs. */
638 for (i = 0; i <= res; i++)
639 if (buffer[i] == '\0')
640 buffer[i] = ' ';
641
642 /* Make sure result is printable. */
643 quoted = kstrdup_quotable(buffer, gfp);
644 kfree(buffer);
645 return quoted;
646}
647EXPORT_SYMBOL_GPL(kstrdup_quotable_cmdline);
648
649/*
650 * Returns allocated NULL-terminated string containing pathname,
651 * with special characters escaped, able to be safely logged. If
652 * there is an error, the leading character will be "<".
653 */
654char *kstrdup_quotable_file(struct file *file, gfp_t gfp)
655{
656 char *temp, *pathname;
657
658 if (!file)
659 return kstrdup("<unknown>", gfp);
660
661 /* We add 11 spaces for ' (deleted)' to be appended */
662 temp = kmalloc(PATH_MAX + 11, GFP_KERNEL);
663 if (!temp)
664 return kstrdup("<no_memory>", gfp);
665
666 pathname = file_path(file, temp, PATH_MAX + 11);
667 if (IS_ERR(pathname))
668 pathname = kstrdup("<too_long>", gfp);
669 else
670 pathname = kstrdup_quotable(pathname, gfp);
671
672 kfree(temp);
673 return pathname;
674}
675EXPORT_SYMBOL_GPL(kstrdup_quotable_file);
676
677/**
678 * kfree_strarray - free a number of dynamically allocated strings contained
679 * in an array and the array itself
680 *
681 * @array: Dynamically allocated array of strings to free.
682 * @n: Number of strings (starting from the beginning of the array) to free.
683 *
684 * Passing a non-NULL @array and @n == 0 as well as NULL @array are valid
685 * use-cases. If @array is NULL, the function does nothing.
686 */
687void kfree_strarray(char **array, size_t n)
688{
689 unsigned int i;
690
691 if (!array)
692 return;
693
694 for (i = 0; i < n; i++)
695 kfree(array[i]);
696 kfree(array);
697}
698EXPORT_SYMBOL_GPL(kfree_strarray);
699
700/**
701 * strscpy_pad() - Copy a C-string into a sized buffer
702 * @dest: Where to copy the string to
703 * @src: Where to copy the string from
704 * @count: Size of destination buffer
705 *
706 * Copy the string, or as much of it as fits, into the dest buffer. The
707 * behavior is undefined if the string buffers overlap. The destination
708 * buffer is always %NUL terminated, unless it's zero-sized.
709 *
710 * If the source string is shorter than the destination buffer, zeros
711 * the tail of the destination buffer.
712 *
713 * For full explanation of why you may want to consider using the
714 * 'strscpy' functions please see the function docstring for strscpy().
715 *
716 * Returns:
717 * * The number of characters copied (not including the trailing %NUL)
718 * * -E2BIG if count is 0 or @src was truncated.
719 */
720ssize_t strscpy_pad(char *dest, const char *src, size_t count)
721{
722 ssize_t written;
723
724 written = strscpy(dest, src, count);
725 if (written < 0 || written == count - 1)
726 return written;
727
728 memset(dest + written + 1, 0, count - written - 1);
729
730 return written;
731}
732EXPORT_SYMBOL(strscpy_pad);
733
734/**
735 * skip_spaces - Removes leading whitespace from @str.
736 * @str: The string to be stripped.
737 *
738 * Returns a pointer to the first non-whitespace character in @str.
739 */
740char *skip_spaces(const char *str)
741{
742 while (isspace(*str))
743 ++str;
744 return (char *)str;
745}
746EXPORT_SYMBOL(skip_spaces);
747
748/**
749 * strim - Removes leading and trailing whitespace from @s.
750 * @s: The string to be stripped.
751 *
752 * Note that the first trailing whitespace is replaced with a %NUL-terminator
753 * in the given string @s. Returns a pointer to the first non-whitespace
754 * character in @s.
755 */
756char *strim(char *s)
757{
758 size_t size;
759 char *end;
760
761 size = strlen(s);
762 if (!size)
763 return s;
764
765 end = s + size - 1;
766 while (end >= s && isspace(*end))
767 end--;
768 *(end + 1) = '\0';
769
770 return skip_spaces(s);
771}
772EXPORT_SYMBOL(strim);
773
774/**
775 * sysfs_streq - return true if strings are equal, modulo trailing newline
776 * @s1: one string
777 * @s2: another string
778 *
779 * This routine returns true iff two strings are equal, treating both
780 * NUL and newline-then-NUL as equivalent string terminations. It's
781 * geared for use with sysfs input strings, which generally terminate
782 * with newlines but are compared against values without newlines.
783 */
784bool sysfs_streq(const char *s1, const char *s2)
785{
786 while (*s1 && *s1 == *s2) {
787 s1++;
788 s2++;
789 }
790
791 if (*s1 == *s2)
792 return true;
793 if (!*s1 && *s2 == '\n' && !s2[1])
794 return true;
795 if (*s1 == '\n' && !s1[1] && !*s2)
796 return true;
797 return false;
798}
799EXPORT_SYMBOL(sysfs_streq);
800
801/**
802 * match_string - matches given string in an array
803 * @array: array of strings
804 * @n: number of strings in the array or -1 for NULL terminated arrays
805 * @string: string to match with
806 *
807 * This routine will look for a string in an array of strings up to the
808 * n-th element in the array or until the first NULL element.
809 *
810 * Historically the value of -1 for @n, was used to search in arrays that
811 * are NULL terminated. However, the function does not make a distinction
812 * when finishing the search: either @n elements have been compared OR
813 * the first NULL element was found.
814 *
815 * Return:
816 * index of a @string in the @array if matches, or %-EINVAL otherwise.
817 */
818int match_string(const char * const *array, size_t n, const char *string)
819{
820 int index;
821 const char *item;
822
823 for (index = 0; index < n; index++) {
824 item = array[index];
825 if (!item)
826 break;
827 if (!strcmp(item, string))
828 return index;
829 }
830
831 return -EINVAL;
832}
833EXPORT_SYMBOL(match_string);
834
835/**
836 * __sysfs_match_string - matches given string in an array
837 * @array: array of strings
838 * @n: number of strings in the array or -1 for NULL terminated arrays
839 * @str: string to match with
840 *
841 * Returns index of @str in the @array or -EINVAL, just like match_string().
842 * Uses sysfs_streq instead of strcmp for matching.
843 *
844 * This routine will look for a string in an array of strings up to the
845 * n-th element in the array or until the first NULL element.
846 *
847 * Historically the value of -1 for @n, was used to search in arrays that
848 * are NULL terminated. However, the function does not make a distinction
849 * when finishing the search: either @n elements have been compared OR
850 * the first NULL element was found.
851 */
852int __sysfs_match_string(const char * const *array, size_t n, const char *str)
853{
854 const char *item;
855 int index;
856
857 for (index = 0; index < n; index++) {
858 item = array[index];
859 if (!item)
860 break;
861 if (sysfs_streq(item, str))
862 return index;
863 }
864
865 return -EINVAL;
866}
867EXPORT_SYMBOL(__sysfs_match_string);
868
869/**
870 * strreplace - Replace all occurrences of character in string.
871 * @s: The string to operate on.
872 * @old: The character being replaced.
873 * @new: The character @old is replaced with.
874 *
875 * Returns pointer to the nul byte at the end of @s.
876 */
877char *strreplace(char *s, char old, char new)
878{
879 for (; *s; ++s)
880 if (*s == old)
881 *s = new;
882 return s;
883}
884EXPORT_SYMBOL(strreplace);
885
886/**
887 * memcpy_and_pad - Copy one buffer to another with padding
888 * @dest: Where to copy to
889 * @dest_len: The destination buffer size
890 * @src: Where to copy from
891 * @count: The number of bytes to copy
892 * @pad: Character to use for padding if space is left in destination.
893 */
894void memcpy_and_pad(void *dest, size_t dest_len, const void *src, size_t count,
895 int pad)
896{
897 if (dest_len > count) {
898 memcpy(dest, src, count);
899 memset(dest + count, pad, dest_len - count);
900 } else {
901 memcpy(dest, src, dest_len);
902 }
903}
904EXPORT_SYMBOL(memcpy_and_pad);
905
906#ifdef CONFIG_FORTIFY_SOURCE
907void fortify_panic(const char *name)
908{
909 pr_emerg("detected buffer overflow in %s\n", name);
910 BUG();
911}
912EXPORT_SYMBOL(fortify_panic);
913#endif /* CONFIG_FORTIFY_SOURCE */