drivers/staging/lustre/lustre/libcfs/libcfs_string.c

   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.sun.com/software/products/lustre/docs/GPLv2.pdf
  19  *
  20  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
  21  * CA 95054 USA or visit www.sun.com if you need additional information or
  22  * have any questions.
  23  *
  24  * GPL HEADER END
  25  */
  26 /*
  27  * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
  28  * Use is subject to license terms.
  29  *
  30  * Copyright (c) 2012, 2015 Intel Corporation.
  31  */
  32 /*
  33  * This file is part of Lustre, http://www.lustre.org/
  34  * Lustre is a trademark of Sun Microsystems, Inc.
  35  *
  36  * String manipulation functions.
  37  *
  38  * libcfs/libcfs/libcfs_string.c
  39  *
  40  * Author: Nathan Rutman <nathan.rutman@sun.com>
  41  */
  42
  43 #include "../../include/linux/libcfs/libcfs.h"
  44
  45 /* Convert a text string to a bitmask */
  46 int cfs_str2mask(const char *str, const char *(*bit2str)(int bit),
  47                  int *oldmask, int minmask, int allmask)
  48 {
  49         const char *debugstr;
  50         char op = '\0';
  51         int newmask = minmask, i, len, found = 0;
  52
  53         /* <str> must be a list of tokens separated by whitespace
  54          * and optionally an operator ('+' or '-').  If an operator
  55          * appears first in <str>, '*oldmask' is used as the starting point
  56          * (relative), otherwise minmask is used (absolute).  An operator
  57          * applies to all following tokens up to the next operator. */
  58         while (*str != '\0') {
  59                 while (isspace(*str))
  60                         str++;
  61                 if (*str == '\0')
  62                         break;
  63                 if (*str == '+' || *str == '-') {
  64                         op = *str++;
  65                         if (!found)
  66                                 /* only if first token is relative */
  67                                 newmask = *oldmask;
  68                         while (isspace(*str))
  69                                 str++;
  70                         if (*str == '\0')  /* trailing op */
  71                                 return -EINVAL;
  72                 }
  73
  74                 /* find token length */
  75                 len = 0;
  76                 while (str[len] != '\0' && !isspace(str[len]) &&
  77                        str[len] != '+' && str[len] != '-')
  78                         len++;
  79
  80                 /* match token */
  81                 found = 0;
  82                 for (i = 0; i < 32; i++) {
  83                         debugstr = bit2str(i);
  84                         if (debugstr != NULL &&
  85                             strlen(debugstr) == len &&
  86                             strncasecmp(str, debugstr, len) == 0) {
  87                                 if (op == '-')
  88                                         newmask &= ~(1 << i);
  89                                 else
  90                                         newmask |= (1 << i);
  91                                 found = 1;
  92                                 break;
  93                         }
  94                 }
  95                 if (!found && len == 3 &&
  96                     (strncasecmp(str, "ALL", len) == 0)) {
  97                         if (op == '-')
  98                                 newmask = minmask;
  99                         else
 100                                 newmask = allmask;
 101                         found = 1;
 102                 }
 103                 if (!found) {
 104                         CWARN("unknown mask '%.*s'.\n"
 105                               "mask usage: [+|-]<all|type> ...\n", len, str);
 106                         return -EINVAL;
 107                 }
 108                 str += len;
 109         }
 110
 111         *oldmask = newmask;
 112         return 0;
 113 }
 114
 115 /* get the first string out of @str */
 116 char *cfs_firststr(char *str, size_t size)
 117 {
 118         size_t i = 0;
 119         char  *end;
 120
 121         /* trim leading spaces */
 122         while (i < size && *str && isspace(*str)) {
 123                 ++i;
 124                 ++str;
 125         }
 126
 127         /* string with all spaces */
 128         if (*str == '\0')
 129                 goto out;
 130
 131         end = str;
 132         while (i < size && *end != '\0' && !isspace(*end)) {
 133                 ++i;
 134                 ++end;
 135         }
 136
 137         *end = '\0';
 138 out:
 139         return str;
 140 }
 141 EXPORT_SYMBOL(cfs_firststr);
 142
 143 char *
 144 cfs_trimwhite(char *str)
 145 {
 146         char *end;
 147
 148         while (isspace(*str))
 149                 str++;
 150
 151         end = str + strlen(str);
 152         while (end > str) {
 153                 if (!isspace(end[-1]))
 154                         break;
 155                 end--;
 156         }
 157
 158         *end = 0;
 159         return str;
 160 }
 161 EXPORT_SYMBOL(cfs_trimwhite);
 162
 163 /**
 164  * Extracts tokens from strings.
 165  *
 166  * Looks for \a delim in string \a next, sets \a res to point to
 167  * substring before the delimiter, sets \a next right after the found
 168  * delimiter.
 169  *
 170  * \retval 1 if \a res points to a string of non-whitespace characters
 171  * \retval 0 otherwise
 172  */
 173 int
 174 cfs_gettok(struct cfs_lstr *next, char delim, struct cfs_lstr *res)
 175 {
 176         char *end;
 177
 178         if (next->ls_str == NULL)
 179                 return 0;
 180
 181         /* skip leading white spaces */
 182         while (next->ls_len) {
 183                 if (!isspace(*next->ls_str))
 184                         break;
 185                 next->ls_str++;
 186                 next->ls_len--;
 187         }
 188
 189         if (next->ls_len == 0) /* whitespaces only */
 190                 return 0;
 191
 192         if (*next->ls_str == delim) {
 193                 /* first non-writespace is the delimiter */
 194                 return 0;
 195         }
 196
 197         res->ls_str = next->ls_str;
 198         end = memchr(next->ls_str, delim, next->ls_len);
 199         if (end == NULL) {
 200                 /* there is no the delimeter in the string */
 201                 end = next->ls_str + next->ls_len;
 202                 next->ls_str = NULL;
 203         } else {
 204                 next->ls_str = end + 1;
 205                 next->ls_len -= (end - res->ls_str + 1);
 206         }
 207
 208         /* skip ending whitespaces */
 209         while (--end != res->ls_str) {
 210                 if (!isspace(*end))
 211                         break;
 212         }
 213
 214         res->ls_len = end - res->ls_str + 1;
 215         return 1;
 216 }
 217 EXPORT_SYMBOL(cfs_gettok);
 218
 219 /**
 220  * Converts string to integer.
 221  *
 222  * Accepts decimal and hexadecimal number recordings.
 223  *
 224  * \retval 1 if first \a nob chars of \a str convert to decimal or
 225  * hexadecimal integer in the range [\a min, \a max]
 226  * \retval 0 otherwise
 227  */
 228 int
 229 cfs_str2num_check(char *str, int nob, unsigned *num,
 230                   unsigned min, unsigned max)
 231 {
 232         char    *endp;
 233
 234         str = cfs_trimwhite(str);
 235         *num = simple_strtoul(str, &endp, 0);
 236         if (endp == str)
 237                 return 0;
 238
 239         for (; endp < str + nob; endp++) {
 240                 if (!isspace(*endp))
 241                         return 0;
 242         }
 243
 244         return (*num >= min && *num <= max);
 245 }
 246 EXPORT_SYMBOL(cfs_str2num_check);
 247
 248 /**
 249  * Parses \<range_expr\> token of the syntax. If \a bracketed is false,
 250  * \a src should only have a single token which can be \<number\> or  \*
 251  *
 252  * \retval pointer to allocated range_expr and initialized
 253  * range_expr::re_lo, range_expr::re_hi and range_expr:re_stride if \a
 254  `* src parses to
 255  * \<number\> |
 256  * \<number\> '-' \<number\> |
 257  * \<number\> '-' \<number\> '/' \<number\>
 258  * \retval 0 will be returned if it can be parsed, otherwise -EINVAL or
 259  * -ENOMEM will be returned.
 260  */
 261 static int
 262 cfs_range_expr_parse(struct cfs_lstr *src, unsigned min, unsigned max,
 263                      int bracketed, struct cfs_range_expr **expr)
 264 {
 265         struct cfs_range_expr   *re;
 266         struct cfs_lstr         tok;
 267
 268         LIBCFS_ALLOC(re, sizeof(*re));
 269         if (re == NULL)
 270                 return -ENOMEM;
 271
 272         if (src->ls_len == 1 && src->ls_str[0] == '*') {
 273                 re->re_lo = min;
 274                 re->re_hi = max;
 275                 re->re_stride = 1;
 276                 goto out;
 277         }
 278
 279         if (cfs_str2num_check(src->ls_str, src->ls_len,
 280                               &re->re_lo, min, max)) {
 281                 /* <number> is parsed */
 282                 re->re_hi = re->re_lo;
 283                 re->re_stride = 1;
 284                 goto out;
 285         }
 286
 287         if (!bracketed || !cfs_gettok(src, '-', &tok))
 288                 goto failed;
 289
 290         if (!cfs_str2num_check(tok.ls_str, tok.ls_len,
 291                                &re->re_lo, min, max))
 292                 goto failed;
 293
 294         /* <number> - */
 295         if (cfs_str2num_check(src->ls_str, src->ls_len,
 296                               &re->re_hi, min, max)) {
 297                 /* <number> - <number> is parsed */
 298                 re->re_stride = 1;
 299                 goto out;
 300         }
 301
 302         /* go to check <number> '-' <number> '/' <number> */
 303         if (cfs_gettok(src, '/', &tok)) {
 304                 if (!cfs_str2num_check(tok.ls_str, tok.ls_len,
 305                                        &re->re_hi, min, max))
 306                         goto failed;
 307
 308                 /* <number> - <number> / ... */
 309                 if (cfs_str2num_check(src->ls_str, src->ls_len,
 310                                       &re->re_stride, min, max)) {
 311                         /* <number> - <number> / <number> is parsed */
 312                         goto out;
 313                 }
 314         }
 315
 316  out:
 317         *expr = re;
 318         return 0;
 319
 320  failed:
 321         LIBCFS_FREE(re, sizeof(*re));
 322         return -EINVAL;
 323 }
 324
 325 /**
 326  * Print the range expression \a re into specified \a buffer.
 327  * If \a bracketed is true, expression does not need additional
 328  * brackets.
 329  *
 330  * \retval number of characters written
 331  */
 332 static int
 333 cfs_range_expr_print(char *buffer, int count, struct cfs_range_expr *expr,
 334                      bool bracketed)
 335 {
 336         int i;
 337         char s[] = "[";
 338         char e[] = "]";
 339
 340         if (bracketed)
 341                 s[0] = e[0] = '\0';
 342
 343         if (expr->re_lo == expr->re_hi)
 344                 i = scnprintf(buffer, count, "%u", expr->re_lo);
 345         else if (expr->re_stride == 1)
 346                 i = scnprintf(buffer, count, "%s%u-%u%s",
 347                                 s, expr->re_lo, expr->re_hi, e);
 348         else
 349                 i = scnprintf(buffer, count, "%s%u-%u/%u%s",
 350                                 s, expr->re_lo, expr->re_hi,
 351                                 expr->re_stride, e);
 352         return i;
 353 }
 354
 355 /**
 356  * Print a list of range expressions (\a expr_list) into specified \a buffer.
 357  * If the list contains several expressions, separate them with comma
 358  * and surround the list with brackets.
 359  *
 360  * \retval number of characters written
 361  */
 362 int
 363 cfs_expr_list_print(char *buffer, int count, struct cfs_expr_list *expr_list)
 364 {
 365         struct cfs_range_expr *expr;
 366         int i = 0, j = 0;
 367         int numexprs = 0;
 368
 369         if (count <= 0)
 370                 return 0;
 371
 372         list_for_each_entry(expr, &expr_list->el_exprs, re_link)
 373                 numexprs++;
 374
 375         if (numexprs > 1)
 376                 i += scnprintf(buffer + i, count - i, "[");
 377
 378         list_for_each_entry(expr, &expr_list->el_exprs, re_link) {
 379                 if (j++ != 0)
 380                         i += scnprintf(buffer + i, count - i, ",");
 381                 i += cfs_range_expr_print(buffer + i, count - i, expr,
 382                                           numexprs > 1);
 383         }
 384
 385         if (numexprs > 1)
 386                 i += scnprintf(buffer + i, count - i, "]");
 387
 388         return i;
 389 }
 390 EXPORT_SYMBOL(cfs_expr_list_print);
 391
 392 /**
 393  * Matches value (\a value) against ranges expression list \a expr_list.
 394  *
 395  * \retval 1 if \a value matches
 396  * \retval 0 otherwise
 397  */
 398 int
 399 cfs_expr_list_match(__u32 value, struct cfs_expr_list *expr_list)
 400 {
 401         struct cfs_range_expr   *expr;
 402
 403         list_for_each_entry(expr, &expr_list->el_exprs, re_link) {
 404                 if (value >= expr->re_lo && value <= expr->re_hi &&
 405                     ((value - expr->re_lo) % expr->re_stride) == 0)
 406                         return 1;
 407         }
 408
 409         return 0;
 410 }
 411 EXPORT_SYMBOL(cfs_expr_list_match);
 412
 413 /**
 414  * Convert express list (\a expr_list) to an array of all matched values
 415  *
 416  * \retval N N is total number of all matched values
 417  * \retval 0 if expression list is empty
 418  * \retval < 0 for failure
 419  */
 420 int
 421 cfs_expr_list_values(struct cfs_expr_list *expr_list, int max, __u32 **valpp)
 422 {
 423         struct cfs_range_expr   *expr;
 424         __u32                   *val;
 425         int                     count = 0;
 426         int                     i;
 427
 428         list_for_each_entry(expr, &expr_list->el_exprs, re_link) {
 429                 for (i = expr->re_lo; i <= expr->re_hi; i++) {
 430                         if (((i - expr->re_lo) % expr->re_stride) == 0)
 431                                 count++;
 432                 }
 433         }
 434
 435         if (count == 0) /* empty expression list */
 436                 return 0;
 437
 438         if (count > max) {
 439                 CERROR("Number of values %d exceeds max allowed %d\n",
 440                        max, count);
 441                 return -EINVAL;
 442         }
 443
 444         LIBCFS_ALLOC(val, sizeof(val[0]) * count);
 445         if (val == NULL)
 446                 return -ENOMEM;
 447
 448         count = 0;
 449         list_for_each_entry(expr, &expr_list->el_exprs, re_link) {
 450                 for (i = expr->re_lo; i <= expr->re_hi; i++) {
 451                         if (((i - expr->re_lo) % expr->re_stride) == 0)
 452                                 val[count++] = i;
 453                 }
 454         }
 455
 456         *valpp = val;
 457         return count;
 458 }
 459 EXPORT_SYMBOL(cfs_expr_list_values);
 460
 461 /**
 462  * Frees cfs_range_expr structures of \a expr_list.
 463  *
 464  * \retval none
 465  */
 466 void
 467 cfs_expr_list_free(struct cfs_expr_list *expr_list)
 468 {
 469         while (!list_empty(&expr_list->el_exprs)) {
 470                 struct cfs_range_expr *expr;
 471
 472                 expr = list_entry(expr_list->el_exprs.next,
 473                                       struct cfs_range_expr, re_link);
 474                 list_del(&expr->re_link);
 475                 LIBCFS_FREE(expr, sizeof(*expr));
 476         }
 477
 478         LIBCFS_FREE(expr_list, sizeof(*expr_list));
 479 }
 480 EXPORT_SYMBOL(cfs_expr_list_free);
 481
 482 /**
 483  * Parses \<cfs_expr_list\> token of the syntax.
 484  *
 485  * \retval 0 if \a str parses to \<number\> | \<expr_list\>
 486  * \retval -errno otherwise
 487  */
 488 int
 489 cfs_expr_list_parse(char *str, int len, unsigned min, unsigned max,
 490                     struct cfs_expr_list **elpp)
 491 {
 492         struct cfs_expr_list    *expr_list;
 493         struct cfs_range_expr   *expr;
 494         struct cfs_lstr         src;
 495         int                     rc;
 496
 497         LIBCFS_ALLOC(expr_list, sizeof(*expr_list));
 498         if (expr_list == NULL)
 499                 return -ENOMEM;
 500
 501         src.ls_str = str;
 502         src.ls_len = len;
 503
 504         INIT_LIST_HEAD(&expr_list->el_exprs);
 505
 506         if (src.ls_str[0] == '[' &&
 507             src.ls_str[src.ls_len - 1] == ']') {
 508                 src.ls_str++;
 509                 src.ls_len -= 2;
 510
 511                 rc = -EINVAL;
 512                 while (src.ls_str != NULL) {
 513                         struct cfs_lstr tok;
 514
 515                         if (!cfs_gettok(&src, ',', &tok)) {
 516                                 rc = -EINVAL;
 517                                 break;
 518                         }
 519
 520                         rc = cfs_range_expr_parse(&tok, min, max, 1, &expr);
 521                         if (rc != 0)
 522                                 break;
 523
 524                         list_add_tail(&expr->re_link,
 525                                           &expr_list->el_exprs);
 526                 }
 527         } else {
 528                 rc = cfs_range_expr_parse(&src, min, max, 0, &expr);
 529                 if (rc == 0) {
 530                         list_add_tail(&expr->re_link,
 531                                           &expr_list->el_exprs);
 532                 }
 533         }
 534
 535         if (rc != 0)
 536                 cfs_expr_list_free(expr_list);
 537         else
 538                 *elpp = expr_list;
 539
 540         return rc;
 541 }
 542 EXPORT_SYMBOL(cfs_expr_list_parse);
 543
 544 /**
 545  * Frees cfs_expr_list structures of \a list.
 546  *
 547  * For each struct cfs_expr_list structure found on \a list it frees
 548  * range_expr list attached to it and frees the cfs_expr_list itself.
 549  *
 550  * \retval none
 551  */
 552 void
 553 cfs_expr_list_free_list(struct list_head *list)
 554 {
 555         struct cfs_expr_list *el;
 556
 557         while (!list_empty(list)) {
 558                 el = list_entry(list->next,
 559                                     struct cfs_expr_list, el_link);
 560                 list_del(&el->el_link);
 561                 cfs_expr_list_free(el);
 562         }
 563 }
 564 EXPORT_SYMBOL(cfs_expr_list_free_list);