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          */
  59         while (*str != '\0') {
  60                 while (isspace(*str))
  61                         str++;
  62                 if (*str == '\0')
  63                         break;
  64                 if (*str == '+' || *str == '-') {
  65                         op = *str++;
  66                         if (!found)
  67                                 /* only if first token is relative */
  68                                 newmask = *oldmask;
  69                         while (isspace(*str))
  70                                 str++;
  71                         if (*str == '\0')  /* trailing op */
  72                                 return -EINVAL;
  73                 }
  74
  75                 /* find token length */
  76                 len = 0;
  77                 while (str[len] != '\0' && !isspace(str[len]) &&
  78                        str[len] != '+' && str[len] != '-')
  79                         len++;
  80
  81                 /* match token */
  82                 found = 0;
  83                 for (i = 0; i < 32; i++) {
  84                         debugstr = bit2str(i);
  85                         if (debugstr && 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)
 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) {
 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         int rc;
 233
 234         str = cfs_trimwhite(str);
 235         rc = kstrtouint(str, 10, num);
 236         if (rc)
 237                 return 0;
 238
 239         return (*num >= min && *num <= max);
 240 }
 241 EXPORT_SYMBOL(cfs_str2num_check);
 242
 243 /**
 244  * Parses \<range_expr\> token of the syntax. If \a bracketed is false,
 245  * \a src should only have a single token which can be \<number\> or  \*
 246  *
 247  * \retval pointer to allocated range_expr and initialized
 248  * range_expr::re_lo, range_expr::re_hi and range_expr:re_stride if \a
 249  `* src parses to
 250  * \<number\> |
 251  * \<number\> '-' \<number\> |
 252  * \<number\> '-' \<number\> '/' \<number\>
 253  * \retval 0 will be returned if it can be parsed, otherwise -EINVAL or
 254  * -ENOMEM will be returned.
 255  */
 256 static int
 257 cfs_range_expr_parse(struct cfs_lstr *src, unsigned min, unsigned max,
 258                      int bracketed, struct cfs_range_expr **expr)
 259 {
 260         struct cfs_range_expr   *re;
 261         struct cfs_lstr         tok;
 262
 263         LIBCFS_ALLOC(re, sizeof(*re));
 264         if (!re)
 265                 return -ENOMEM;
 266
 267         if (src->ls_len == 1 && src->ls_str[0] == '*') {
 268                 re->re_lo = min;
 269                 re->re_hi = max;
 270                 re->re_stride = 1;
 271                 goto out;
 272         }
 273
 274         if (cfs_str2num_check(src->ls_str, src->ls_len,
 275                               &re->re_lo, min, max)) {
 276                 /* <number> is parsed */
 277                 re->re_hi = re->re_lo;
 278                 re->re_stride = 1;
 279                 goto out;
 280         }
 281
 282         if (!bracketed || !cfs_gettok(src, '-', &tok))
 283                 goto failed;
 284
 285         if (!cfs_str2num_check(tok.ls_str, tok.ls_len,
 286                                &re->re_lo, min, max))
 287                 goto failed;
 288
 289         /* <number> - */
 290         if (cfs_str2num_check(src->ls_str, src->ls_len,
 291                               &re->re_hi, min, max)) {
 292                 /* <number> - <number> is parsed */
 293                 re->re_stride = 1;
 294                 goto out;
 295         }
 296
 297         /* go to check <number> '-' <number> '/' <number> */
 298         if (cfs_gettok(src, '/', &tok)) {
 299                 if (!cfs_str2num_check(tok.ls_str, tok.ls_len,
 300                                        &re->re_hi, min, max))
 301                         goto failed;
 302
 303                 /* <number> - <number> / ... */
 304                 if (cfs_str2num_check(src->ls_str, src->ls_len,
 305                                       &re->re_stride, min, max)) {
 306                         /* <number> - <number> / <number> is parsed */
 307                         goto out;
 308                 }
 309         }
 310
 311  out:
 312         *expr = re;
 313         return 0;
 314
 315  failed:
 316         LIBCFS_FREE(re, sizeof(*re));
 317         return -EINVAL;
 318 }
 319
 320 /**
 321  * Print the range expression \a re into specified \a buffer.
 322  * If \a bracketed is true, expression does not need additional
 323  * brackets.
 324  *
 325  * \retval number of characters written
 326  */
 327 static int
 328 cfs_range_expr_print(char *buffer, int count, struct cfs_range_expr *expr,
 329                      bool bracketed)
 330 {
 331         int i;
 332         char s[] = "[";
 333         char e[] = "]";
 334
 335         if (bracketed) {
 336                 s[0] = '\0';
 337                 e[0] = '\0';
 338         }
 339
 340         if (expr->re_lo == expr->re_hi)
 341                 i = scnprintf(buffer, count, "%u", expr->re_lo);
 342         else if (expr->re_stride == 1)
 343                 i = scnprintf(buffer, count, "%s%u-%u%s",
 344                               s, expr->re_lo, expr->re_hi, e);
 345         else
 346                 i = scnprintf(buffer, count, "%s%u-%u/%u%s",
 347                               s, expr->re_lo, expr->re_hi, expr->re_stride, e);
 348         return i;
 349 }
 350
 351 /**
 352  * Print a list of range expressions (\a expr_list) into specified \a buffer.
 353  * If the list contains several expressions, separate them with comma
 354  * and surround the list with brackets.
 355  *
 356  * \retval number of characters written
 357  */
 358 int
 359 cfs_expr_list_print(char *buffer, int count, struct cfs_expr_list *expr_list)
 360 {
 361         struct cfs_range_expr *expr;
 362         int i = 0, j = 0;
 363         int numexprs = 0;
 364
 365         if (count <= 0)
 366                 return 0;
 367
 368         list_for_each_entry(expr, &expr_list->el_exprs, re_link)
 369                 numexprs++;
 370
 371         if (numexprs > 1)
 372                 i += scnprintf(buffer + i, count - i, "[");
 373
 374         list_for_each_entry(expr, &expr_list->el_exprs, re_link) {
 375                 if (j++ != 0)
 376                         i += scnprintf(buffer + i, count - i, ",");
 377                 i += cfs_range_expr_print(buffer + i, count - i, expr,
 378                                           numexprs > 1);
 379         }
 380
 381         if (numexprs > 1)
 382                 i += scnprintf(buffer + i, count - i, "]");
 383
 384         return i;
 385 }
 386 EXPORT_SYMBOL(cfs_expr_list_print);
 387
 388 /**
 389  * Matches value (\a value) against ranges expression list \a expr_list.
 390  *
 391  * \retval 1 if \a value matches
 392  * \retval 0 otherwise
 393  */
 394 int
 395 cfs_expr_list_match(__u32 value, struct cfs_expr_list *expr_list)
 396 {
 397         struct cfs_range_expr   *expr;
 398
 399         list_for_each_entry(expr, &expr_list->el_exprs, re_link) {
 400                 if (value >= expr->re_lo && value <= expr->re_hi &&
 401                     ((value - expr->re_lo) % expr->re_stride) == 0)
 402                         return 1;
 403         }
 404
 405         return 0;
 406 }
 407 EXPORT_SYMBOL(cfs_expr_list_match);
 408
 409 /**
 410  * Convert express list (\a expr_list) to an array of all matched values
 411  *
 412  * \retval N N is total number of all matched values
 413  * \retval 0 if expression list is empty
 414  * \retval < 0 for failure
 415  */
 416 int
 417 cfs_expr_list_values(struct cfs_expr_list *expr_list, int max, __u32 **valpp)
 418 {
 419         struct cfs_range_expr   *expr;
 420         __u32                   *val;
 421         int                     count = 0;
 422         int                     i;
 423
 424         list_for_each_entry(expr, &expr_list->el_exprs, re_link) {
 425                 for (i = expr->re_lo; i <= expr->re_hi; i++) {
 426                         if (((i - expr->re_lo) % expr->re_stride) == 0)
 427                                 count++;
 428                 }
 429         }
 430
 431         if (count == 0) /* empty expression list */
 432                 return 0;
 433
 434         if (count > max) {
 435                 CERROR("Number of values %d exceeds max allowed %d\n",
 436                        max, count);
 437                 return -EINVAL;
 438         }
 439
 440         LIBCFS_ALLOC(val, sizeof(val[0]) * count);
 441         if (!val)
 442                 return -ENOMEM;
 443
 444         count = 0;
 445         list_for_each_entry(expr, &expr_list->el_exprs, re_link) {
 446                 for (i = expr->re_lo; i <= expr->re_hi; i++) {
 447                         if (((i - expr->re_lo) % expr->re_stride) == 0)
 448                                 val[count++] = i;
 449                 }
 450         }
 451
 452         *valpp = val;
 453         return count;
 454 }
 455 EXPORT_SYMBOL(cfs_expr_list_values);
 456
 457 /**
 458  * Frees cfs_range_expr structures of \a expr_list.
 459  *
 460  * \retval none
 461  */
 462 void
 463 cfs_expr_list_free(struct cfs_expr_list *expr_list)
 464 {
 465         while (!list_empty(&expr_list->el_exprs)) {
 466                 struct cfs_range_expr *expr;
 467
 468                 expr = list_entry(expr_list->el_exprs.next,
 469                                   struct cfs_range_expr, re_link);
 470                 list_del(&expr->re_link);
 471                 LIBCFS_FREE(expr, sizeof(*expr));
 472         }
 473
 474         LIBCFS_FREE(expr_list, sizeof(*expr_list));
 475 }
 476 EXPORT_SYMBOL(cfs_expr_list_free);
 477
 478 /**
 479  * Parses \<cfs_expr_list\> token of the syntax.
 480  *
 481  * \retval 0 if \a str parses to \<number\> | \<expr_list\>
 482  * \retval -errno otherwise
 483  */
 484 int
 485 cfs_expr_list_parse(char *str, int len, unsigned min, unsigned max,
 486                     struct cfs_expr_list **elpp)
 487 {
 488         struct cfs_expr_list    *expr_list;
 489         struct cfs_range_expr   *expr;
 490         struct cfs_lstr         src;
 491         int                     rc;
 492
 493         LIBCFS_ALLOC(expr_list, sizeof(*expr_list));
 494         if (!expr_list)
 495                 return -ENOMEM;
 496
 497         src.ls_str = str;
 498         src.ls_len = len;
 499
 500         INIT_LIST_HEAD(&expr_list->el_exprs);
 501
 502         if (src.ls_str[0] == '[' &&
 503             src.ls_str[src.ls_len - 1] == ']') {
 504                 src.ls_str++;
 505                 src.ls_len -= 2;
 506
 507                 rc = -EINVAL;
 508                 while (src.ls_str) {
 509                         struct cfs_lstr tok;
 510
 511                         if (!cfs_gettok(&src, ',', &tok)) {
 512                                 rc = -EINVAL;
 513                                 break;
 514                         }
 515
 516                         rc = cfs_range_expr_parse(&tok, min, max, 1, &expr);
 517                         if (rc != 0)
 518                                 break;
 519
 520                         list_add_tail(&expr->re_link, &expr_list->el_exprs);
 521                 }
 522         } else {
 523                 rc = cfs_range_expr_parse(&src, min, max, 0, &expr);
 524                 if (rc == 0)
 525                         list_add_tail(&expr->re_link, &expr_list->el_exprs);
 526         }
 527
 528         if (rc != 0)
 529                 cfs_expr_list_free(expr_list);
 530         else
 531                 *elpp = expr_list;
 532
 533         return rc;
 534 }
 535 EXPORT_SYMBOL(cfs_expr_list_parse);
 536
 537 /**
 538  * Frees cfs_expr_list structures of \a list.
 539  *
 540  * For each struct cfs_expr_list structure found on \a list it frees
 541  * range_expr list attached to it and frees the cfs_expr_list itself.
 542  *
 543  * \retval none
 544  */
 545 void
 546 cfs_expr_list_free_list(struct list_head *list)
 547 {
 548         struct cfs_expr_list *el;
 549
 550         while (!list_empty(list)) {
 551                 el = list_entry(list->next, struct cfs_expr_list, el_link);
 552                 list_del(&el->el_link);
 553                 cfs_expr_list_free(el);
 554         }
 555 }
 556 EXPORT_SYMBOL(cfs_expr_list_free_list);