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 */
string_get_size(u64 size,u64 blk_size,const enum string_size_units units,char * buf,int len)39 int 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 }
139 EXPORT_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 */
parse_int_array_user(const char __user * from,size_t count,int ** array)154 int 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
179 free_buf:
180 kfree(buf);
181 return ret;
182 }
183 EXPORT_SYMBOL(parse_int_array_user);
184
unescape_space(char ** src,char ** dst)185 static 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
unescape_octal(char ** src,char ** dst)213 static 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
unescape_hex(char ** src,char ** dst)232 static 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
unescape_special(char ** src,char ** dst)256 static 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 */
string_unescape(char * src,char * dst,size_t size,unsigned int flags)320 int string_unescape(char *src, char *dst, size_t size, unsigned int flags)
321 {
322 char *out = dst;
323
324 if (!size)
325 size = SIZE_MAX;
326
327 while (*src && --size) {
328 if (src[0] == '\\' && src[1] != '\0' && size > 1) {
329 src++;
330 size--;
331
332 if (flags & UNESCAPE_SPACE &&
333 unescape_space(&src, &out))
334 continue;
335
336 if (flags & UNESCAPE_OCTAL &&
337 unescape_octal(&src, &out))
338 continue;
339
340 if (flags & UNESCAPE_HEX &&
341 unescape_hex(&src, &out))
342 continue;
343
344 if (flags & UNESCAPE_SPECIAL &&
345 unescape_special(&src, &out))
346 continue;
347
348 *out++ = '\\';
349 }
350 *out++ = *src++;
351 }
352 *out = '\0';
353
354 return out - dst;
355 }
356 EXPORT_SYMBOL(string_unescape);
357
escape_passthrough(unsigned char c,char ** dst,char * end)358 static bool escape_passthrough(unsigned char c, char **dst, char *end)
359 {
360 char *out = *dst;
361
362 if (out < end)
363 *out = c;
364 *dst = out + 1;
365 return true;
366 }
367
escape_space(unsigned char c,char ** dst,char * end)368 static bool escape_space(unsigned char c, char **dst, char *end)
369 {
370 char *out = *dst;
371 unsigned char to;
372
373 switch (c) {
374 case '\n':
375 to = 'n';
376 break;
377 case '\r':
378 to = 'r';
379 break;
380 case '\t':
381 to = 't';
382 break;
383 case '\v':
384 to = 'v';
385 break;
386 case '\f':
387 to = 'f';
388 break;
389 default:
390 return false;
391 }
392
393 if (out < end)
394 *out = '\\';
395 ++out;
396 if (out < end)
397 *out = to;
398 ++out;
399
400 *dst = out;
401 return true;
402 }
403
escape_special(unsigned char c,char ** dst,char * end)404 static bool escape_special(unsigned char c, char **dst, char *end)
405 {
406 char *out = *dst;
407 unsigned char to;
408
409 switch (c) {
410 case '\\':
411 to = '\\';
412 break;
413 case '\a':
414 to = 'a';
415 break;
416 case '\e':
417 to = 'e';
418 break;
419 case '"':
420 to = '"';
421 break;
422 default:
423 return false;
424 }
425
426 if (out < end)
427 *out = '\\';
428 ++out;
429 if (out < end)
430 *out = to;
431 ++out;
432
433 *dst = out;
434 return true;
435 }
436
escape_null(unsigned char c,char ** dst,char * end)437 static bool escape_null(unsigned char c, char **dst, char *end)
438 {
439 char *out = *dst;
440
441 if (c)
442 return false;
443
444 if (out < end)
445 *out = '\\';
446 ++out;
447 if (out < end)
448 *out = '0';
449 ++out;
450
451 *dst = out;
452 return true;
453 }
454
escape_octal(unsigned char c,char ** dst,char * end)455 static bool escape_octal(unsigned char c, char **dst, char *end)
456 {
457 char *out = *dst;
458
459 if (out < end)
460 *out = '\\';
461 ++out;
462 if (out < end)
463 *out = ((c >> 6) & 0x07) + '0';
464 ++out;
465 if (out < end)
466 *out = ((c >> 3) & 0x07) + '0';
467 ++out;
468 if (out < end)
469 *out = ((c >> 0) & 0x07) + '0';
470 ++out;
471
472 *dst = out;
473 return true;
474 }
475
escape_hex(unsigned char c,char ** dst,char * end)476 static bool escape_hex(unsigned char c, char **dst, char *end)
477 {
478 char *out = *dst;
479
480 if (out < end)
481 *out = '\\';
482 ++out;
483 if (out < end)
484 *out = 'x';
485 ++out;
486 if (out < end)
487 *out = hex_asc_hi(c);
488 ++out;
489 if (out < end)
490 *out = hex_asc_lo(c);
491 ++out;
492
493 *dst = out;
494 return true;
495 }
496
497 /**
498 * string_escape_mem - quote characters in the given memory buffer
499 * @src: source buffer (unescaped)
500 * @isz: source buffer size
501 * @dst: destination buffer (escaped)
502 * @osz: destination buffer size
503 * @flags: combination of the flags
504 * @only: NULL-terminated string containing characters used to limit
505 * the selected escape class. If characters are included in @only
506 * that would not normally be escaped by the classes selected
507 * in @flags, they will be copied to @dst unescaped.
508 *
509 * Description:
510 * The process of escaping byte buffer includes several parts. They are applied
511 * in the following sequence.
512 *
513 * 1. The character is not matched to the one from @only string and thus
514 * must go as-is to the output.
515 * 2. The character is matched to the printable and ASCII classes, if asked,
516 * and in case of match it passes through to the output.
517 * 3. The character is matched to the printable or ASCII class, if asked,
518 * and in case of match it passes through to the output.
519 * 4. The character is checked if it falls into the class given by @flags.
520 * %ESCAPE_OCTAL and %ESCAPE_HEX are going last since they cover any
521 * character. Note that they actually can't go together, otherwise
522 * %ESCAPE_HEX will be ignored.
523 *
524 * Caller must provide valid source and destination pointers. Be aware that
525 * destination buffer will not be NULL-terminated, thus caller have to append
526 * it if needs. The supported flags are::
527 *
528 * %ESCAPE_SPACE: (special white space, not space itself)
529 * '\f' - form feed
530 * '\n' - new line
531 * '\r' - carriage return
532 * '\t' - horizontal tab
533 * '\v' - vertical tab
534 * %ESCAPE_SPECIAL:
535 * '\"' - double quote
536 * '\\' - backslash
537 * '\a' - alert (BEL)
538 * '\e' - escape
539 * %ESCAPE_NULL:
540 * '\0' - null
541 * %ESCAPE_OCTAL:
542 * '\NNN' - byte with octal value NNN (3 digits)
543 * %ESCAPE_ANY:
544 * all previous together
545 * %ESCAPE_NP:
546 * escape only non-printable characters, checked by isprint()
547 * %ESCAPE_ANY_NP:
548 * all previous together
549 * %ESCAPE_HEX:
550 * '\xHH' - byte with hexadecimal value HH (2 digits)
551 * %ESCAPE_NA:
552 * escape only non-ascii characters, checked by isascii()
553 * %ESCAPE_NAP:
554 * escape only non-printable or non-ascii characters
555 * %ESCAPE_APPEND:
556 * append characters from @only to be escaped by the given classes
557 *
558 * %ESCAPE_APPEND would help to pass additional characters to the escaped, when
559 * one of %ESCAPE_NP, %ESCAPE_NA, or %ESCAPE_NAP is provided.
560 *
561 * One notable caveat, the %ESCAPE_NAP, %ESCAPE_NP and %ESCAPE_NA have the
562 * higher priority than the rest of the flags (%ESCAPE_NAP is the highest).
563 * It doesn't make much sense to use either of them without %ESCAPE_OCTAL
564 * or %ESCAPE_HEX, because they cover most of the other character classes.
565 * %ESCAPE_NAP can utilize %ESCAPE_SPACE or %ESCAPE_SPECIAL in addition to
566 * the above.
567 *
568 * Return:
569 * The total size of the escaped output that would be generated for
570 * the given input and flags. To check whether the output was
571 * truncated, compare the return value to osz. There is room left in
572 * dst for a '\0' terminator if and only if ret < osz.
573 */
string_escape_mem(const char * src,size_t isz,char * dst,size_t osz,unsigned int flags,const char * only)574 int string_escape_mem(const char *src, size_t isz, char *dst, size_t osz,
575 unsigned int flags, const char *only)
576 {
577 char *p = dst;
578 char *end = p + osz;
579 bool is_dict = only && *only;
580 bool is_append = flags & ESCAPE_APPEND;
581
582 while (isz--) {
583 unsigned char c = *src++;
584 bool in_dict = is_dict && strchr(only, c);
585
586 /*
587 * Apply rules in the following sequence:
588 * - the @only string is supplied and does not contain a
589 * character under question
590 * - the character is printable and ASCII, when @flags has
591 * %ESCAPE_NAP bit set
592 * - the character is printable, when @flags has
593 * %ESCAPE_NP bit set
594 * - the character is ASCII, when @flags has
595 * %ESCAPE_NA bit set
596 * - the character doesn't fall into a class of symbols
597 * defined by given @flags
598 * In these cases we just pass through a character to the
599 * output buffer.
600 *
601 * When %ESCAPE_APPEND is passed, the characters from @only
602 * have been excluded from the %ESCAPE_NAP, %ESCAPE_NP, and
603 * %ESCAPE_NA cases.
604 */
605 if (!(is_append || in_dict) && is_dict &&
606 escape_passthrough(c, &p, end))
607 continue;
608
609 if (!(is_append && in_dict) && isascii(c) && isprint(c) &&
610 flags & ESCAPE_NAP && escape_passthrough(c, &p, end))
611 continue;
612
613 if (!(is_append && in_dict) && isprint(c) &&
614 flags & ESCAPE_NP && escape_passthrough(c, &p, end))
615 continue;
616
617 if (!(is_append && in_dict) && isascii(c) &&
618 flags & ESCAPE_NA && escape_passthrough(c, &p, end))
619 continue;
620
621 if (flags & ESCAPE_SPACE && escape_space(c, &p, end))
622 continue;
623
624 if (flags & ESCAPE_SPECIAL && escape_special(c, &p, end))
625 continue;
626
627 if (flags & ESCAPE_NULL && escape_null(c, &p, end))
628 continue;
629
630 /* ESCAPE_OCTAL and ESCAPE_HEX always go last */
631 if (flags & ESCAPE_OCTAL && escape_octal(c, &p, end))
632 continue;
633
634 if (flags & ESCAPE_HEX && escape_hex(c, &p, end))
635 continue;
636
637 escape_passthrough(c, &p, end);
638 }
639
640 return p - dst;
641 }
642 EXPORT_SYMBOL(string_escape_mem);
643
644 /*
645 * Return an allocated string that has been escaped of special characters
646 * and double quotes, making it safe to log in quotes.
647 */
kstrdup_quotable(const char * src,gfp_t gfp)648 char *kstrdup_quotable(const char *src, gfp_t gfp)
649 {
650 size_t slen, dlen;
651 char *dst;
652 const int flags = ESCAPE_HEX;
653 const char esc[] = "\f\n\r\t\v\a\e\\\"";
654
655 if (!src)
656 return NULL;
657 slen = strlen(src);
658
659 dlen = string_escape_mem(src, slen, NULL, 0, flags, esc);
660 dst = kmalloc(dlen + 1, gfp);
661 if (!dst)
662 return NULL;
663
664 WARN_ON(string_escape_mem(src, slen, dst, dlen, flags, esc) != dlen);
665 dst[dlen] = '\0';
666
667 return dst;
668 }
669 EXPORT_SYMBOL_GPL(kstrdup_quotable);
670
671 /*
672 * Returns allocated NULL-terminated string containing process
673 * command line, with inter-argument NULLs replaced with spaces,
674 * and other special characters escaped.
675 */
kstrdup_quotable_cmdline(struct task_struct * task,gfp_t gfp)676 char *kstrdup_quotable_cmdline(struct task_struct *task, gfp_t gfp)
677 {
678 char *buffer, *quoted;
679 int i, res;
680
681 buffer = kmalloc(PAGE_SIZE, GFP_KERNEL);
682 if (!buffer)
683 return NULL;
684
685 res = get_cmdline(task, buffer, PAGE_SIZE - 1);
686 buffer[res] = '\0';
687
688 /* Collapse trailing NULLs, leave res pointing to last non-NULL. */
689 while (--res >= 0 && buffer[res] == '\0')
690 ;
691
692 /* Replace inter-argument NULLs. */
693 for (i = 0; i <= res; i++)
694 if (buffer[i] == '\0')
695 buffer[i] = ' ';
696
697 /* Make sure result is printable. */
698 quoted = kstrdup_quotable(buffer, gfp);
699 kfree(buffer);
700 return quoted;
701 }
702 EXPORT_SYMBOL_GPL(kstrdup_quotable_cmdline);
703
704 /*
705 * Returns allocated NULL-terminated string containing pathname,
706 * with special characters escaped, able to be safely logged. If
707 * there is an error, the leading character will be "<".
708 */
kstrdup_quotable_file(struct file * file,gfp_t gfp)709 char *kstrdup_quotable_file(struct file *file, gfp_t gfp)
710 {
711 char *temp, *pathname;
712
713 if (!file)
714 return kstrdup("<unknown>", gfp);
715
716 /* We add 11 spaces for ' (deleted)' to be appended */
717 temp = kmalloc(PATH_MAX + 11, GFP_KERNEL);
718 if (!temp)
719 return kstrdup("<no_memory>", gfp);
720
721 pathname = file_path(file, temp, PATH_MAX + 11);
722 if (IS_ERR(pathname))
723 pathname = kstrdup("<too_long>", gfp);
724 else
725 pathname = kstrdup_quotable(pathname, gfp);
726
727 kfree(temp);
728 return pathname;
729 }
730 EXPORT_SYMBOL_GPL(kstrdup_quotable_file);
731
732 /*
733 * Returns duplicate string in which the @old characters are replaced by @new.
734 */
kstrdup_and_replace(const char * src,char old,char new,gfp_t gfp)735 char *kstrdup_and_replace(const char *src, char old, char new, gfp_t gfp)
736 {
737 char *dst;
738
739 dst = kstrdup(src, gfp);
740 if (!dst)
741 return NULL;
742
743 return strreplace(dst, old, new);
744 }
745 EXPORT_SYMBOL_GPL(kstrdup_and_replace);
746
747 /**
748 * kasprintf_strarray - allocate and fill array of sequential strings
749 * @gfp: flags for the slab allocator
750 * @prefix: prefix to be used
751 * @n: amount of lines to be allocated and filled
752 *
753 * Allocates and fills @n strings using pattern "%s-%zu", where prefix
754 * is provided by caller. The caller is responsible to free them with
755 * kfree_strarray() after use.
756 *
757 * Returns array of strings or NULL when memory can't be allocated.
758 */
kasprintf_strarray(gfp_t gfp,const char * prefix,size_t n)759 char **kasprintf_strarray(gfp_t gfp, const char *prefix, size_t n)
760 {
761 char **names;
762 size_t i;
763
764 names = kcalloc(n + 1, sizeof(char *), gfp);
765 if (!names)
766 return NULL;
767
768 for (i = 0; i < n; i++) {
769 names[i] = kasprintf(gfp, "%s-%zu", prefix, i);
770 if (!names[i]) {
771 kfree_strarray(names, i);
772 return NULL;
773 }
774 }
775
776 return names;
777 }
778 EXPORT_SYMBOL_GPL(kasprintf_strarray);
779
780 /**
781 * kfree_strarray - free a number of dynamically allocated strings contained
782 * in an array and the array itself
783 *
784 * @array: Dynamically allocated array of strings to free.
785 * @n: Number of strings (starting from the beginning of the array) to free.
786 *
787 * Passing a non-NULL @array and @n == 0 as well as NULL @array are valid
788 * use-cases. If @array is NULL, the function does nothing.
789 */
kfree_strarray(char ** array,size_t n)790 void kfree_strarray(char **array, size_t n)
791 {
792 unsigned int i;
793
794 if (!array)
795 return;
796
797 for (i = 0; i < n; i++)
798 kfree(array[i]);
799 kfree(array);
800 }
801 EXPORT_SYMBOL_GPL(kfree_strarray);
802
803 struct strarray {
804 char **array;
805 size_t n;
806 };
807
devm_kfree_strarray(struct device * dev,void * res)808 static void devm_kfree_strarray(struct device *dev, void *res)
809 {
810 struct strarray *array = res;
811
812 kfree_strarray(array->array, array->n);
813 }
814
devm_kasprintf_strarray(struct device * dev,const char * prefix,size_t n)815 char **devm_kasprintf_strarray(struct device *dev, const char *prefix, size_t n)
816 {
817 struct strarray *ptr;
818
819 ptr = devres_alloc(devm_kfree_strarray, sizeof(*ptr), GFP_KERNEL);
820 if (!ptr)
821 return ERR_PTR(-ENOMEM);
822
823 ptr->array = kasprintf_strarray(GFP_KERNEL, prefix, n);
824 if (!ptr->array) {
825 devres_free(ptr);
826 return ERR_PTR(-ENOMEM);
827 }
828
829 ptr->n = n;
830 devres_add(dev, ptr);
831
832 return ptr->array;
833 }
834 EXPORT_SYMBOL_GPL(devm_kasprintf_strarray);
835
836 /**
837 * skip_spaces - Removes leading whitespace from @str.
838 * @str: The string to be stripped.
839 *
840 * Returns a pointer to the first non-whitespace character in @str.
841 */
skip_spaces(const char * str)842 char *skip_spaces(const char *str)
843 {
844 while (isspace(*str))
845 ++str;
846 return (char *)str;
847 }
848 EXPORT_SYMBOL(skip_spaces);
849
850 /**
851 * strim - Removes leading and trailing whitespace from @s.
852 * @s: The string to be stripped.
853 *
854 * Note that the first trailing whitespace is replaced with a %NUL-terminator
855 * in the given string @s. Returns a pointer to the first non-whitespace
856 * character in @s.
857 */
strim(char * s)858 char *strim(char *s)
859 {
860 size_t size;
861 char *end;
862
863 size = strlen(s);
864 if (!size)
865 return s;
866
867 end = s + size - 1;
868 while (end >= s && isspace(*end))
869 end--;
870 *(end + 1) = '\0';
871
872 return skip_spaces(s);
873 }
874 EXPORT_SYMBOL(strim);
875
876 /**
877 * sysfs_streq - return true if strings are equal, modulo trailing newline
878 * @s1: one string
879 * @s2: another string
880 *
881 * This routine returns true iff two strings are equal, treating both
882 * NUL and newline-then-NUL as equivalent string terminations. It's
883 * geared for use with sysfs input strings, which generally terminate
884 * with newlines but are compared against values without newlines.
885 */
sysfs_streq(const char * s1,const char * s2)886 bool sysfs_streq(const char *s1, const char *s2)
887 {
888 while (*s1 && *s1 == *s2) {
889 s1++;
890 s2++;
891 }
892
893 if (*s1 == *s2)
894 return true;
895 if (!*s1 && *s2 == '\n' && !s2[1])
896 return true;
897 if (*s1 == '\n' && !s1[1] && !*s2)
898 return true;
899 return false;
900 }
901 EXPORT_SYMBOL(sysfs_streq);
902
903 /**
904 * match_string - matches given string in an array
905 * @array: array of strings
906 * @n: number of strings in the array or -1 for NULL terminated arrays
907 * @string: string to match with
908 *
909 * This routine will look for a string in an array of strings up to the
910 * n-th element in the array or until the first NULL element.
911 *
912 * Historically the value of -1 for @n, was used to search in arrays that
913 * are NULL terminated. However, the function does not make a distinction
914 * when finishing the search: either @n elements have been compared OR
915 * the first NULL element was found.
916 *
917 * Return:
918 * index of a @string in the @array if matches, or %-EINVAL otherwise.
919 */
match_string(const char * const * array,size_t n,const char * string)920 int match_string(const char * const *array, size_t n, const char *string)
921 {
922 int index;
923 const char *item;
924
925 for (index = 0; index < n; index++) {
926 item = array[index];
927 if (!item)
928 break;
929 if (!strcmp(item, string))
930 return index;
931 }
932
933 return -EINVAL;
934 }
935 EXPORT_SYMBOL(match_string);
936
937 /**
938 * __sysfs_match_string - matches given string in an array
939 * @array: array of strings
940 * @n: number of strings in the array or -1 for NULL terminated arrays
941 * @str: string to match with
942 *
943 * Returns index of @str in the @array or -EINVAL, just like match_string().
944 * Uses sysfs_streq instead of strcmp for matching.
945 *
946 * This routine will look for a string in an array of strings up to the
947 * n-th element in the array or until the first NULL element.
948 *
949 * Historically the value of -1 for @n, was used to search in arrays that
950 * are NULL terminated. However, the function does not make a distinction
951 * when finishing the search: either @n elements have been compared OR
952 * the first NULL element was found.
953 */
__sysfs_match_string(const char * const * array,size_t n,const char * str)954 int __sysfs_match_string(const char * const *array, size_t n, const char *str)
955 {
956 const char *item;
957 int index;
958
959 for (index = 0; index < n; index++) {
960 item = array[index];
961 if (!item)
962 break;
963 if (sysfs_streq(item, str))
964 return index;
965 }
966
967 return -EINVAL;
968 }
969 EXPORT_SYMBOL(__sysfs_match_string);
970
971 /**
972 * strreplace - Replace all occurrences of character in string.
973 * @str: The string to operate on.
974 * @old: The character being replaced.
975 * @new: The character @old is replaced with.
976 *
977 * Replaces the each @old character with a @new one in the given string @str.
978 *
979 * Return: pointer to the string @str itself.
980 */
strreplace(char * str,char old,char new)981 char *strreplace(char *str, char old, char new)
982 {
983 char *s = str;
984
985 for (; *s; ++s)
986 if (*s == old)
987 *s = new;
988 return str;
989 }
990 EXPORT_SYMBOL(strreplace);
991
992 /**
993 * memcpy_and_pad - Copy one buffer to another with padding
994 * @dest: Where to copy to
995 * @dest_len: The destination buffer size
996 * @src: Where to copy from
997 * @count: The number of bytes to copy
998 * @pad: Character to use for padding if space is left in destination.
999 */
memcpy_and_pad(void * dest,size_t dest_len,const void * src,size_t count,int pad)1000 void memcpy_and_pad(void *dest, size_t dest_len, const void *src, size_t count,
1001 int pad)
1002 {
1003 if (dest_len > count) {
1004 memcpy(dest, src, count);
1005 memset(dest + count, pad, dest_len - count);
1006 } else {
1007 memcpy(dest, src, dest_len);
1008 }
1009 }
1010 EXPORT_SYMBOL(memcpy_and_pad);
1011
1012 #ifdef CONFIG_FORTIFY_SOURCE
1013 /* These are placeholders for fortify compile-time warnings. */
__read_overflow2_field(size_t avail,size_t wanted)1014 void __read_overflow2_field(size_t avail, size_t wanted) { }
1015 EXPORT_SYMBOL(__read_overflow2_field);
__write_overflow_field(size_t avail,size_t wanted)1016 void __write_overflow_field(size_t avail, size_t wanted) { }
1017 EXPORT_SYMBOL(__write_overflow_field);
1018
1019 static const char * const fortify_func_name[] = {
1020 #define MAKE_FORTIFY_FUNC_NAME(func) [MAKE_FORTIFY_FUNC(func)] = #func
1021 EACH_FORTIFY_FUNC(MAKE_FORTIFY_FUNC_NAME)
1022 #undef MAKE_FORTIFY_FUNC_NAME
1023 };
1024
__fortify_report(const u8 reason,const size_t avail,const size_t size)1025 void __fortify_report(const u8 reason, const size_t avail, const size_t size)
1026 {
1027 const u8 func = FORTIFY_REASON_FUNC(reason);
1028 const bool write = FORTIFY_REASON_DIR(reason);
1029 const char *name;
1030
1031 name = fortify_func_name[umin(func, FORTIFY_FUNC_UNKNOWN)];
1032 WARN(1, "%s: detected buffer overflow: %zu byte %s of buffer size %zu\n",
1033 name, size, str_read_write(!write), avail);
1034 }
1035 EXPORT_SYMBOL(__fortify_report);
1036
__fortify_panic(const u8 reason,const size_t avail,const size_t size)1037 void __fortify_panic(const u8 reason, const size_t avail, const size_t size)
1038 {
1039 __fortify_report(reason, avail, size);
1040 BUG();
1041 }
1042 EXPORT_SYMBOL(__fortify_panic);
1043 #endif /* CONFIG_FORTIFY_SOURCE */
1044