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1 /*
2  * GPL HEADER START
3  *
4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License version 2 only,
8  * as published by the Free Software Foundation.
9  *
10  * This program is distributed in the hope that it will be useful, but
11  * WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13  * General Public License version 2 for more details (a copy is included
14  * in the LICENSE file that accompanied this code).
15  *
16  * You should have received a copy of the GNU General Public License
17  * version 2 along with this program; If not, see
18  * http://www.gnu.org/licenses/gpl-2.0.html
19  *
20  * GPL HEADER END
21  */
22 /*
23  * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
24  * Use is subject to license terms.
25  *
26  * Copyright (c) 2012, 2015 Intel Corporation.
27  */
28 /*
29  * This file is part of Lustre, http://www.lustre.org/
30  * Lustre is a trademark of Sun Microsystems, Inc.
31  *
32  * String manipulation functions.
33  *
34  * libcfs/libcfs/libcfs_string.c
35  *
36  * Author: Nathan Rutman <nathan.rutman@sun.com>
37  */
38 
39 #include "../../include/linux/libcfs/libcfs.h"
40 
41 /* Convert a text string to a bitmask */
cfs_str2mask(const char * str,const char * (* bit2str)(int bit),int * oldmask,int minmask,int allmask)42 int cfs_str2mask(const char *str, const char *(*bit2str)(int bit),
43 		 int *oldmask, int minmask, int allmask)
44 {
45 	const char *debugstr;
46 	char op = '\0';
47 	int newmask = minmask, i, len, found = 0;
48 
49 	/* <str> must be a list of tokens separated by whitespace
50 	 * and optionally an operator ('+' or '-').  If an operator
51 	 * appears first in <str>, '*oldmask' is used as the starting point
52 	 * (relative), otherwise minmask is used (absolute).  An operator
53 	 * applies to all following tokens up to the next operator.
54 	 */
55 	while (*str != '\0') {
56 		while (isspace(*str))
57 			str++;
58 		if (*str == '\0')
59 			break;
60 		if (*str == '+' || *str == '-') {
61 			op = *str++;
62 			if (!found)
63 				/* only if first token is relative */
64 				newmask = *oldmask;
65 			while (isspace(*str))
66 				str++;
67 			if (*str == '\0')  /* trailing op */
68 				return -EINVAL;
69 		}
70 
71 		/* find token length */
72 		len = 0;
73 		while (str[len] != '\0' && !isspace(str[len]) &&
74 		       str[len] != '+' && str[len] != '-')
75 			len++;
76 
77 		/* match token */
78 		found = 0;
79 		for (i = 0; i < 32; i++) {
80 			debugstr = bit2str(i);
81 			if (debugstr && strlen(debugstr) == len &&
82 			    strncasecmp(str, debugstr, len) == 0) {
83 				if (op == '-')
84 					newmask &= ~(1 << i);
85 				else
86 					newmask |= (1 << i);
87 				found = 1;
88 				break;
89 			}
90 		}
91 		if (!found && len == 3 &&
92 		    (strncasecmp(str, "ALL", len) == 0)) {
93 			if (op == '-')
94 				newmask = minmask;
95 			else
96 				newmask = allmask;
97 			found = 1;
98 		}
99 		if (!found) {
100 			CWARN("unknown mask '%.*s'.\n"
101 			      "mask usage: [+|-]<all|type> ...\n", len, str);
102 			return -EINVAL;
103 		}
104 		str += len;
105 	}
106 
107 	*oldmask = newmask;
108 	return 0;
109 }
110 
111 /* get the first string out of @str */
cfs_firststr(char * str,size_t size)112 char *cfs_firststr(char *str, size_t size)
113 {
114 	size_t i = 0;
115 	char  *end;
116 
117 	/* trim leading spaces */
118 	while (i < size && *str && isspace(*str)) {
119 		++i;
120 		++str;
121 	}
122 
123 	/* string with all spaces */
124 	if (*str == '\0')
125 		goto out;
126 
127 	end = str;
128 	while (i < size && *end != '\0' && !isspace(*end)) {
129 		++i;
130 		++end;
131 	}
132 
133 	*end = '\0';
134 out:
135 	return str;
136 }
137 EXPORT_SYMBOL(cfs_firststr);
138 
139 char *
cfs_trimwhite(char * str)140 cfs_trimwhite(char *str)
141 {
142 	char *end;
143 
144 	while (isspace(*str))
145 		str++;
146 
147 	end = str + strlen(str);
148 	while (end > str) {
149 		if (!isspace(end[-1]))
150 			break;
151 		end--;
152 	}
153 
154 	*end = 0;
155 	return str;
156 }
157 EXPORT_SYMBOL(cfs_trimwhite);
158 
159 /**
160  * Extracts tokens from strings.
161  *
162  * Looks for \a delim in string \a next, sets \a res to point to
163  * substring before the delimiter, sets \a next right after the found
164  * delimiter.
165  *
166  * \retval 1 if \a res points to a string of non-whitespace characters
167  * \retval 0 otherwise
168  */
169 int
cfs_gettok(struct cfs_lstr * next,char delim,struct cfs_lstr * res)170 cfs_gettok(struct cfs_lstr *next, char delim, struct cfs_lstr *res)
171 {
172 	char *end;
173 
174 	if (!next->ls_str)
175 		return 0;
176 
177 	/* skip leading white spaces */
178 	while (next->ls_len) {
179 		if (!isspace(*next->ls_str))
180 			break;
181 		next->ls_str++;
182 		next->ls_len--;
183 	}
184 
185 	if (next->ls_len == 0) /* whitespaces only */
186 		return 0;
187 
188 	if (*next->ls_str == delim) {
189 		/* first non-writespace is the delimiter */
190 		return 0;
191 	}
192 
193 	res->ls_str = next->ls_str;
194 	end = memchr(next->ls_str, delim, next->ls_len);
195 	if (!end) {
196 		/* there is no the delimeter in the string */
197 		end = next->ls_str + next->ls_len;
198 		next->ls_str = NULL;
199 	} else {
200 		next->ls_str = end + 1;
201 		next->ls_len -= (end - res->ls_str + 1);
202 	}
203 
204 	/* skip ending whitespaces */
205 	while (--end != res->ls_str) {
206 		if (!isspace(*end))
207 			break;
208 	}
209 
210 	res->ls_len = end - res->ls_str + 1;
211 	return 1;
212 }
213 EXPORT_SYMBOL(cfs_gettok);
214 
215 /**
216  * Converts string to integer.
217  *
218  * Accepts decimal and hexadecimal number recordings.
219  *
220  * \retval 1 if first \a nob chars of \a str convert to decimal or
221  * hexadecimal integer in the range [\a min, \a max]
222  * \retval 0 otherwise
223  */
224 int
cfs_str2num_check(char * str,int nob,unsigned * num,unsigned min,unsigned max)225 cfs_str2num_check(char *str, int nob, unsigned *num,
226 		  unsigned min, unsigned max)
227 {
228 	bool all_numbers = true;
229 	char *endp, cache;
230 	int rc;
231 
232 	/**
233 	 * kstrouint can only handle strings composed
234 	 * of only numbers. We need to scan the string
235 	 * passed in for the first non-digit character
236 	 * and end the string at that location. If we
237 	 * don't find any non-digit character we still
238 	 * need to place a '\0' at position nob since
239 	 * we are not interested in the rest of the
240 	 * string which is longer than nob in size.
241 	 * After we are done the character at the
242 	 * position we placed '\0' must be restored.
243 	 */
244 	for (endp = str; endp < str + nob; endp++) {
245 		if (!isdigit(*endp)) {
246 			all_numbers = false;
247 			break;
248 		}
249 	}
250 	cache = *endp;
251 	*endp = '\0';
252 
253 	rc = kstrtouint(str, 10, num);
254 	*endp = cache;
255 	if (rc || !all_numbers)
256 		return 0;
257 
258 	return (*num >= min && *num <= max);
259 }
260 EXPORT_SYMBOL(cfs_str2num_check);
261 
262 /**
263  * Parses \<range_expr\> token of the syntax. If \a bracketed is false,
264  * \a src should only have a single token which can be \<number\> or  \*
265  *
266  * \retval pointer to allocated range_expr and initialized
267  * range_expr::re_lo, range_expr::re_hi and range_expr:re_stride if \a
268  `* src parses to
269  * \<number\> |
270  * \<number\> '-' \<number\> |
271  * \<number\> '-' \<number\> '/' \<number\>
272  * \retval 0 will be returned if it can be parsed, otherwise -EINVAL or
273  * -ENOMEM will be returned.
274  */
275 static int
cfs_range_expr_parse(struct cfs_lstr * src,unsigned min,unsigned max,int bracketed,struct cfs_range_expr ** expr)276 cfs_range_expr_parse(struct cfs_lstr *src, unsigned min, unsigned max,
277 		     int bracketed, struct cfs_range_expr **expr)
278 {
279 	struct cfs_range_expr	*re;
280 	struct cfs_lstr		tok;
281 
282 	LIBCFS_ALLOC(re, sizeof(*re));
283 	if (!re)
284 		return -ENOMEM;
285 
286 	if (src->ls_len == 1 && src->ls_str[0] == '*') {
287 		re->re_lo = min;
288 		re->re_hi = max;
289 		re->re_stride = 1;
290 		goto out;
291 	}
292 
293 	if (cfs_str2num_check(src->ls_str, src->ls_len,
294 			      &re->re_lo, min, max)) {
295 		/* <number> is parsed */
296 		re->re_hi = re->re_lo;
297 		re->re_stride = 1;
298 		goto out;
299 	}
300 
301 	if (!bracketed || !cfs_gettok(src, '-', &tok))
302 		goto failed;
303 
304 	if (!cfs_str2num_check(tok.ls_str, tok.ls_len,
305 			       &re->re_lo, min, max))
306 		goto failed;
307 
308 	/* <number> - */
309 	if (cfs_str2num_check(src->ls_str, src->ls_len,
310 			      &re->re_hi, min, max)) {
311 		/* <number> - <number> is parsed */
312 		re->re_stride = 1;
313 		goto out;
314 	}
315 
316 	/* go to check <number> '-' <number> '/' <number> */
317 	if (cfs_gettok(src, '/', &tok)) {
318 		if (!cfs_str2num_check(tok.ls_str, tok.ls_len,
319 				       &re->re_hi, min, max))
320 			goto failed;
321 
322 		/* <number> - <number> / ... */
323 		if (cfs_str2num_check(src->ls_str, src->ls_len,
324 				      &re->re_stride, min, max)) {
325 			/* <number> - <number> / <number> is parsed */
326 			goto out;
327 		}
328 	}
329 
330  out:
331 	*expr = re;
332 	return 0;
333 
334  failed:
335 	LIBCFS_FREE(re, sizeof(*re));
336 	return -EINVAL;
337 }
338 
339 /**
340  * Print the range expression \a re into specified \a buffer.
341  * If \a bracketed is true, expression does not need additional
342  * brackets.
343  *
344  * \retval number of characters written
345  */
346 static int
cfs_range_expr_print(char * buffer,int count,struct cfs_range_expr * expr,bool bracketed)347 cfs_range_expr_print(char *buffer, int count, struct cfs_range_expr *expr,
348 		     bool bracketed)
349 {
350 	int i;
351 	char s[] = "[";
352 	char e[] = "]";
353 
354 	if (bracketed) {
355 		s[0] = '\0';
356 		e[0] = '\0';
357 	}
358 
359 	if (expr->re_lo == expr->re_hi)
360 		i = scnprintf(buffer, count, "%u", expr->re_lo);
361 	else if (expr->re_stride == 1)
362 		i = scnprintf(buffer, count, "%s%u-%u%s",
363 			      s, expr->re_lo, expr->re_hi, e);
364 	else
365 		i = scnprintf(buffer, count, "%s%u-%u/%u%s",
366 			      s, expr->re_lo, expr->re_hi, expr->re_stride, e);
367 	return i;
368 }
369 
370 /**
371  * Print a list of range expressions (\a expr_list) into specified \a buffer.
372  * If the list contains several expressions, separate them with comma
373  * and surround the list with brackets.
374  *
375  * \retval number of characters written
376  */
377 int
cfs_expr_list_print(char * buffer,int count,struct cfs_expr_list * expr_list)378 cfs_expr_list_print(char *buffer, int count, struct cfs_expr_list *expr_list)
379 {
380 	struct cfs_range_expr *expr;
381 	int i = 0, j = 0;
382 	int numexprs = 0;
383 
384 	if (count <= 0)
385 		return 0;
386 
387 	list_for_each_entry(expr, &expr_list->el_exprs, re_link)
388 		numexprs++;
389 
390 	if (numexprs > 1)
391 		i += scnprintf(buffer + i, count - i, "[");
392 
393 	list_for_each_entry(expr, &expr_list->el_exprs, re_link) {
394 		if (j++ != 0)
395 			i += scnprintf(buffer + i, count - i, ",");
396 		i += cfs_range_expr_print(buffer + i, count - i, expr,
397 					  numexprs > 1);
398 	}
399 
400 	if (numexprs > 1)
401 		i += scnprintf(buffer + i, count - i, "]");
402 
403 	return i;
404 }
405 EXPORT_SYMBOL(cfs_expr_list_print);
406 
407 /**
408  * Matches value (\a value) against ranges expression list \a expr_list.
409  *
410  * \retval 1 if \a value matches
411  * \retval 0 otherwise
412  */
413 int
cfs_expr_list_match(__u32 value,struct cfs_expr_list * expr_list)414 cfs_expr_list_match(__u32 value, struct cfs_expr_list *expr_list)
415 {
416 	struct cfs_range_expr	*expr;
417 
418 	list_for_each_entry(expr, &expr_list->el_exprs, re_link) {
419 		if (value >= expr->re_lo && value <= expr->re_hi &&
420 		    ((value - expr->re_lo) % expr->re_stride) == 0)
421 			return 1;
422 	}
423 
424 	return 0;
425 }
426 EXPORT_SYMBOL(cfs_expr_list_match);
427 
428 /**
429  * Convert express list (\a expr_list) to an array of all matched values
430  *
431  * \retval N N is total number of all matched values
432  * \retval 0 if expression list is empty
433  * \retval < 0 for failure
434  */
435 int
cfs_expr_list_values(struct cfs_expr_list * expr_list,int max,__u32 ** valpp)436 cfs_expr_list_values(struct cfs_expr_list *expr_list, int max, __u32 **valpp)
437 {
438 	struct cfs_range_expr	*expr;
439 	__u32			*val;
440 	int			count = 0;
441 	int			i;
442 
443 	list_for_each_entry(expr, &expr_list->el_exprs, re_link) {
444 		for (i = expr->re_lo; i <= expr->re_hi; i++) {
445 			if (((i - expr->re_lo) % expr->re_stride) == 0)
446 				count++;
447 		}
448 	}
449 
450 	if (count == 0) /* empty expression list */
451 		return 0;
452 
453 	if (count > max) {
454 		CERROR("Number of values %d exceeds max allowed %d\n",
455 		       max, count);
456 		return -EINVAL;
457 	}
458 
459 	LIBCFS_ALLOC(val, sizeof(val[0]) * count);
460 	if (!val)
461 		return -ENOMEM;
462 
463 	count = 0;
464 	list_for_each_entry(expr, &expr_list->el_exprs, re_link) {
465 		for (i = expr->re_lo; i <= expr->re_hi; i++) {
466 			if (((i - expr->re_lo) % expr->re_stride) == 0)
467 				val[count++] = i;
468 		}
469 	}
470 
471 	*valpp = val;
472 	return count;
473 }
474 EXPORT_SYMBOL(cfs_expr_list_values);
475 
476 /**
477  * Frees cfs_range_expr structures of \a expr_list.
478  *
479  * \retval none
480  */
481 void
cfs_expr_list_free(struct cfs_expr_list * expr_list)482 cfs_expr_list_free(struct cfs_expr_list *expr_list)
483 {
484 	while (!list_empty(&expr_list->el_exprs)) {
485 		struct cfs_range_expr *expr;
486 
487 		expr = list_entry(expr_list->el_exprs.next,
488 				  struct cfs_range_expr, re_link);
489 		list_del(&expr->re_link);
490 		LIBCFS_FREE(expr, sizeof(*expr));
491 	}
492 
493 	LIBCFS_FREE(expr_list, sizeof(*expr_list));
494 }
495 EXPORT_SYMBOL(cfs_expr_list_free);
496 
497 /**
498  * Parses \<cfs_expr_list\> token of the syntax.
499  *
500  * \retval 0 if \a str parses to \<number\> | \<expr_list\>
501  * \retval -errno otherwise
502  */
503 int
cfs_expr_list_parse(char * str,int len,unsigned min,unsigned max,struct cfs_expr_list ** elpp)504 cfs_expr_list_parse(char *str, int len, unsigned min, unsigned max,
505 		    struct cfs_expr_list **elpp)
506 {
507 	struct cfs_expr_list	*expr_list;
508 	struct cfs_range_expr	*expr;
509 	struct cfs_lstr		src;
510 	int			rc;
511 
512 	LIBCFS_ALLOC(expr_list, sizeof(*expr_list));
513 	if (!expr_list)
514 		return -ENOMEM;
515 
516 	src.ls_str = str;
517 	src.ls_len = len;
518 
519 	INIT_LIST_HEAD(&expr_list->el_exprs);
520 
521 	if (src.ls_str[0] == '[' &&
522 	    src.ls_str[src.ls_len - 1] == ']') {
523 		src.ls_str++;
524 		src.ls_len -= 2;
525 
526 		rc = -EINVAL;
527 		while (src.ls_str) {
528 			struct cfs_lstr tok;
529 
530 			if (!cfs_gettok(&src, ',', &tok)) {
531 				rc = -EINVAL;
532 				break;
533 			}
534 
535 			rc = cfs_range_expr_parse(&tok, min, max, 1, &expr);
536 			if (rc != 0)
537 				break;
538 
539 			list_add_tail(&expr->re_link, &expr_list->el_exprs);
540 		}
541 	} else {
542 		rc = cfs_range_expr_parse(&src, min, max, 0, &expr);
543 		if (rc == 0)
544 			list_add_tail(&expr->re_link, &expr_list->el_exprs);
545 	}
546 
547 	if (rc != 0)
548 		cfs_expr_list_free(expr_list);
549 	else
550 		*elpp = expr_list;
551 
552 	return rc;
553 }
554 EXPORT_SYMBOL(cfs_expr_list_parse);
555 
556 /**
557  * Frees cfs_expr_list structures of \a list.
558  *
559  * For each struct cfs_expr_list structure found on \a list it frees
560  * range_expr list attached to it and frees the cfs_expr_list itself.
561  *
562  * \retval none
563  */
564 void
cfs_expr_list_free_list(struct list_head * list)565 cfs_expr_list_free_list(struct list_head *list)
566 {
567 	struct cfs_expr_list *el;
568 
569 	while (!list_empty(list)) {
570 		el = list_entry(list->next, struct cfs_expr_list, el_link);
571 		list_del(&el->el_link);
572 		cfs_expr_list_free(el);
573 	}
574 }
575 EXPORT_SYMBOL(cfs_expr_list_free_list);
576