policy.c

   1 /*
   2  * mdadm - manage Linux "md" devices aka RAID arrays.
   3  *
   4  * Copyright (C) 2001-2009 Neil Brown <neilb@suse.de>
   5  *
   6  *
   7  *    This program is free software; you can redistribute it and/or modify
   8  *    it under the terms of the GNU General Public License as published by
   9  *    the Free Software Foundation; either version 2 of the License, or
  10  *    (at your option) any later version.
  11  *
  12  *    This program is distributed in the hope that it will be useful,
  13  *    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  *    GNU General Public License for more details.
  16  *
  17  *    You should have received a copy of the GNU General Public License
  18  *    along with this program; if not, write to the Free Software
  19  *    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  20  *
  21  *    Author: Neil Brown
  22  *    Email: <neilb@suse.de>
  23  */
  24
  25 #include "mdadm.h"
  26 #include <dirent.h>
  27 #include <fnmatch.h>
  28 #include <ctype.h>
  29 #include "dlink.h"
  30 /*
  31  * Policy module for mdadm.
  32  * A policy statement about a device lists a set of values for each
  33  * of a set of names.  Each value can have a metadata type as context.
  34  *
  35  * names include:
  36  *   action - the actions that can be taken on hot-plug
  37  *   domain - the domain(s) that the device is part of
  38  *
  39  * Policy information is extracted from various sources, but
  40  * particularly from a set of policy rules in mdadm.conf
  41  */
  42
  43 static void pol_new(struct dev_policy **pol, char *name, const char *val,
  44                     const char *metadata)
  45 {
  46         struct dev_policy *n = xmalloc(sizeof(*n));
  47         const char *real_metadata = NULL;
  48         int i;
  49
  50         n->name = name;
  51         n->value = val;
  52
  53         /* We need to normalise the metadata name */
  54         if (metadata) {
  55                 for (i = 0; superlist[i] ; i++)
  56                         if (strcmp(metadata, superlist[i]->name) == 0) {
  57                                 real_metadata = superlist[i]->name;
  58                                 break;
  59                         }
  60                 if (!real_metadata) {
  61                         if (strcmp(metadata, "1") == 0 ||
  62                             strcmp(metadata, "1.0") == 0 ||
  63                             strcmp(metadata, "1.1") == 0 ||
  64                             strcmp(metadata, "1.2") == 0)
  65                                 real_metadata = super1.name;
  66                 }
  67                 if (!real_metadata) {
  68                         static const char *prev = NULL;
  69                         if (prev != metadata) {
  70                                 pr_err("metadata=%s unrecognised - ignoring rule\n",
  71                                         metadata);
  72                                 prev = metadata;
  73                         }
  74                         real_metadata = "unknown";
  75                 }
  76         }
  77
  78         n->metadata = real_metadata;
  79         n->next = *pol;
  80         *pol = n;
  81 }
  82
  83 static int pol_lesseq(struct dev_policy *a, struct dev_policy *b)
  84 {
  85         int cmp;
  86
  87         if (a->name < b->name)
  88                 return 1;
  89         if (a->name > b->name)
  90                 return 0;
  91
  92         cmp = strcmp(a->value, b->value);
  93         if (cmp < 0)
  94                 return 1;
  95         if (cmp > 0)
  96                 return 0;
  97
  98         return (a->metadata <= b->metadata);
  99 }
 100
 101 static void pol_sort(struct dev_policy **pol)
 102 {
 103         /* sort policy list in *pol by name/metadata/value
 104          * using merge sort
 105          */
 106
 107         struct dev_policy *pl[2];
 108         pl[0] = *pol;
 109         pl[1] = NULL;
 110
 111         do {
 112                 struct dev_policy **plp[2], *p[2];
 113                 int curr = 0;
 114                 struct dev_policy nul = { NULL, NULL, NULL, NULL };
 115                 struct dev_policy *prev = &nul;
 116                 int next = 0;
 117
 118                 /* p[] are the two lists that we are merging.
 119                  * plp[] are the ends of the two lists we create
 120                  * from the merge.
 121                  * 'curr' is which of plp[] that we are currently
 122                  *   adding items to.
 123                  * 'next' is which if p[] we will take the next
 124                  *   item from.
 125                  * 'prev' is that last value, which was placed in
 126                  * plp[curr].
 127                  */
 128                 plp[0] = &pl[0];
 129                 plp[1] = &pl[1];
 130                 p[0] = pl[0];
 131                 p[1] = pl[1];
 132
 133                 /* take least of p[0] and p[1]
 134                  * if it is larger than prev, add to
 135                  * plp[curr], else swap curr then add
 136                  */
 137                 while (p[0] || p[1]) {
 138                         if (p[next] == NULL ||
 139                             (p[1-next] != NULL &&
 140                              !(pol_lesseq(prev, p[1-next])
 141                                ^pol_lesseq(prev, p[next])
 142                                ^pol_lesseq(p[next], p[1-next])))
 143                                 )
 144                                 next = 1 - next;
 145
 146                         if (!pol_lesseq(prev, p[next]))
 147                                 curr = 1 - curr;
 148
 149                         *plp[curr] = prev = p[next];
 150                         plp[curr] = &p[next]->next;
 151                         p[next] = p[next]->next;
 152                 }
 153                 *plp[0] = NULL;
 154                 *plp[1] = NULL;
 155         } while (pl[0] && pl[1]);
 156         if (pl[0])
 157                 *pol = pl[0];
 158         else
 159                 *pol = pl[1];
 160 }
 161
 162 static void pol_dedup(struct dev_policy *pol)
 163 {
 164         /* This is a sorted list - remove duplicates. */
 165         while (pol && pol->next) {
 166                 if (pol_lesseq(pol->next, pol)) {
 167                         struct dev_policy *tmp = pol->next;
 168                         pol->next = tmp->next;
 169                         free(tmp);
 170                 } else
 171                         pol = pol->next;
 172         }
 173 }
 174
 175 /*
 176  * pol_find finds the first entry in the policy
 177  * list to match name.
 178  * If it returns non-NULL there is at least one
 179  * value, but how many can only be found by
 180  * iterating through the list.
 181  */
 182 struct dev_policy *pol_find(struct dev_policy *pol, char *name)
 183 {
 184         while (pol && pol->name < name)
 185                 pol = pol->next;
 186
 187         if (!pol || pol->name != name)
 188                 return NULL;
 189         return pol;
 190 }
 191
 192 static char **disk_paths(struct mdinfo *disk)
 193 {
 194         struct stat stb;
 195         int prefix_len;
 196         DIR *by_path;
 197         char symlink[PATH_MAX] = "/dev/disk/by-path/";
 198         char **paths;
 199         int cnt = 0;
 200         struct dirent *ent;
 201
 202         paths = xmalloc(sizeof(*paths) * (cnt+1));
 203
 204         by_path = opendir(symlink);
 205         if (by_path) {
 206                 prefix_len = strlen(symlink);
 207                 while ((ent = readdir(by_path)) != NULL) {
 208                         if (ent->d_type != DT_LNK)
 209                                 continue;
 210                         strncpy(symlink + prefix_len,
 211                                         ent->d_name,
 212                                         sizeof(symlink) - prefix_len);
 213                         if (stat(symlink, &stb) < 0)
 214                                 continue;
 215                         if ((stb.st_mode & S_IFMT) != S_IFBLK)
 216                                 continue;
 217                         if (stb.st_rdev != makedev(disk->disk.major, disk->disk.minor))
 218                                 continue;
 219                         paths[cnt++] = xstrdup(ent->d_name);
 220                         paths = xrealloc(paths, sizeof(*paths) * (cnt+1));
 221                 }
 222                 closedir(by_path);
 223         }
 224         paths[cnt] = NULL;
 225         return paths;
 226 }
 227
 228 char type_part[] = "part";
 229 char type_disk[] = "disk";
 230 static char *disk_type(struct mdinfo *disk)
 231 {
 232         char buf[30+20+20];
 233         struct stat stb;
 234         sprintf(buf, "/sys/dev/block/%d:%d/partition",
 235                 disk->disk.major, disk->disk.minor);
 236         if (stat(buf, &stb) == 0)
 237                 return type_part;
 238         else
 239                 return type_disk;
 240 }
 241
 242 static int path_has_part(char *path, char **part)
 243 {
 244         /* check if path ends with "-partNN" and
 245          * if it does, place a pointer to "-pathNN"
 246          * in 'part'.
 247          */
 248         int l;
 249         if (!path)
 250                 return 0;
 251         l = strlen(path);
 252         while (l > 1 && isdigit(path[l-1]))
 253                 l--;
 254         if (l < 5 || strncmp(path+l-5, "-part", 5) != 0)
 255                 return 0;
 256         *part = path+l-5;
 257         return 1;
 258 }
 259
 260 static int pol_match(struct rule *rule, char **paths, char *type, char **part)
 261 {
 262         /* Check if this rule matches on any path and type.
 263          * If 'part' is not NULL, then 'path' must end in -partN, which
 264          * we ignore for matching, and return in *part on success.
 265          */
 266         int pathok = 0; /* 0 == no path, 1 == match, -1 == no match yet */
 267         int typeok = 0;
 268
 269         for (; rule; rule = rule->next) {
 270                 if (rule->name == rule_path) {
 271                         char *p = NULL;
 272                         int i;
 273                         if (pathok == 0)
 274                                 pathok = -1;
 275                         if (!paths)
 276                                 continue;
 277                         for (i = 0; paths[i]; i++) {
 278                                 if (part) {
 279                                         if (!path_has_part(paths[i], &p))
 280                                                 continue;
 281                                         *p = '\0';
 282                                         *part = p+1;
 283                                 }
 284                                 if (fnmatch(rule->value, paths[i], 0) == 0)
 285                                         pathok = 1;
 286                                 if (part)
 287                                         *p = '-';
 288                         }
 289                 }
 290                 if (rule->name == rule_type) {
 291                         if (typeok == 0)
 292                                 typeok = -1;
 293                         if (type && strcmp(rule->value, type) == 0)
 294                                 typeok = 1;
 295                 }
 296         }
 297         return pathok >= 0 && typeok >= 0;
 298 }
 299
 300 static void pol_merge(struct dev_policy **pol, struct rule *rule)
 301 {
 302         /* copy any name assignments from rule into pol */
 303         struct rule *r;
 304         char *metadata = NULL;
 305         for (r = rule; r ; r = r->next)
 306                 if (r->name == pol_metadata)
 307                         metadata = r->value;
 308
 309         for (r = rule; r ; r = r->next)
 310                 if (r->name == pol_act ||
 311                     r->name == pol_domain ||
 312                     r->name == pol_auto)
 313                         pol_new(pol, r->name, r->value, metadata);
 314 }
 315
 316 static void pol_merge_part(struct dev_policy **pol, struct rule *rule, char *part)
 317 {
 318         /* copy any name assignments from rule into pol, appending
 319          * -part to any domain.  The string with -part appended is
 320          * stored with the rule so it has a lifetime to match
 321          * the rule.
 322          */
 323         struct rule *r;
 324         char *metadata = NULL;
 325         for (r = rule; r ; r = r->next)
 326                 if (r->name == pol_metadata)
 327                         metadata = r->value;
 328
 329         for (r = rule; r ; r = r->next) {
 330                 if (r->name == pol_act)
 331                         pol_new(pol, r->name, r->value, metadata);
 332                 else if (r->name == pol_domain) {
 333                         char *dom;
 334                         int len;
 335                         if (r->dups == NULL)
 336                                 r->dups = dl_head();
 337                         len = strlen(r->value);
 338                         for (dom = dl_next(r->dups); dom != r->dups;
 339                              dom = dl_next(dom))
 340                                 if (strcmp(dom+len+1, part)== 0)
 341                                         break;
 342                         if (dom == r->dups) {
 343                                 char *newdom = dl_strndup(
 344                                         r->value, len + 1 + strlen(part));
 345                                 strcat(strcat(newdom, "-"), part);
 346                                 dl_add(r->dups, newdom);
 347                                 dom = newdom;
 348                         }
 349                         pol_new(pol, r->name, dom, metadata);
 350                 }
 351         }
 352 }
 353
 354 static struct pol_rule *config_rules = NULL;
 355 static struct pol_rule **config_rules_end = NULL;
 356 static int config_rules_has_path = 0;
 357
 358 /*
 359  * most policy comes from a set policy rules that are
 360  * read from the config file.
 361  * path_policy() gathers policy information for the
 362  * disk described in the given a 'path' and a 'type'.
 363  */
 364 struct dev_policy *path_policy(char **paths, char *type)
 365 {
 366         struct pol_rule *rules;
 367         struct dev_policy *pol = NULL;
 368         int i;
 369
 370         rules = config_rules;
 371
 372         while (rules) {
 373                 char *part = NULL;
 374                 if (rules->type == rule_policy)
 375                         if (pol_match(rules->rule, paths, type, NULL))
 376                                 pol_merge(&pol, rules->rule);
 377                 if (rules->type == rule_part && strcmp(type, type_part) == 0)
 378                         if (pol_match(rules->rule, paths, type_disk, &part))
 379                                         pol_merge_part(&pol, rules->rule, part);
 380                 rules = rules->next;
 381         }
 382
 383         /* Now add any metadata-specific internal knowledge
 384          * about this path
 385          */
 386         for (i=0; paths && paths[0] && superlist[i]; i++)
 387                 if (superlist[i]->get_disk_controller_domain) {
 388                         const char *d =
 389                                 superlist[i]->get_disk_controller_domain(
 390                                         paths[0]);
 391                         if (d)
 392                                 pol_new(&pol, pol_domain, d, superlist[i]->name);
 393                 }
 394
 395         pol_sort(&pol);
 396         pol_dedup(pol);
 397         return pol;
 398 }
 399
 400 void pol_add(struct dev_policy **pol,
 401                     char *name, char *val,
 402                     char *metadata)
 403 {
 404         pol_new(pol, name, val, metadata);
 405         pol_sort(pol);
 406         pol_dedup(*pol);
 407 }
 408
 409 static void free_paths(char **paths)
 410 {
 411         int i;
 412
 413         if (!paths)
 414                 return;
 415
 416         for (i = 0; paths[i]; i++)
 417                 free(paths[i]);
 418         free(paths);
 419 }
 420
 421 /*
 422  * disk_policy() gathers policy information for the
 423  * disk described in the given mdinfo (disk.{major,minor}).
 424  */
 425 struct dev_policy *disk_policy(struct mdinfo *disk)
 426 {
 427         char **paths = NULL;
 428         char *type = disk_type(disk);
 429         struct dev_policy *pol = NULL;
 430
 431         if (config_rules_has_path)
 432                 paths = disk_paths(disk);
 433
 434         pol = path_policy(paths, type);
 435
 436         free_paths(paths);
 437         return pol;
 438 }
 439
 440 struct dev_policy *devid_policy(int dev)
 441 {
 442         struct mdinfo disk;
 443         disk.disk.major = major(dev);
 444         disk.disk.minor = minor(dev);
 445         return disk_policy(&disk);
 446 }
 447
 448 /*
 449  * process policy rules read from config file.
 450  */
 451
 452 char rule_path[] = "path";
 453 char rule_type[] = "type";
 454
 455 char rule_policy[] = "policy";
 456 char rule_part[] = "part-policy";
 457
 458 char pol_metadata[] = "metadata";
 459 char pol_act[] = "action";
 460 char pol_domain[] = "domain";
 461 char pol_auto[] = "auto";
 462
 463 static int try_rule(char *w, char *name, struct rule **rp)
 464 {
 465         struct rule *r;
 466         int len = strlen(name);
 467         if (strncmp(w, name, len) != 0 ||
 468             w[len] != '=')
 469                 return 0;
 470         r = xmalloc(sizeof(*r));
 471         r->next = *rp;
 472         r->name = name;
 473         r->value = xstrdup(w+len+1);
 474         r->dups = NULL;
 475         *rp = r;
 476         return 1;
 477 }
 478
 479 void policyline(char *line, char *type)
 480 {
 481         struct pol_rule *pr;
 482         char *w;
 483
 484         if (config_rules_end == NULL)
 485                 config_rules_end = &config_rules;
 486
 487         pr = xmalloc(sizeof(*pr));
 488         pr->type = type;
 489         pr->rule = NULL;
 490         for (w = dl_next(line); w != line ; w = dl_next(w)) {
 491                 if (try_rule(w, rule_path, &pr->rule))
 492                         config_rules_has_path = 1;
 493                 else if (! try_rule(w, rule_type, &pr->rule) &&
 494                          ! try_rule(w, pol_metadata, &pr->rule) &&
 495                          ! try_rule(w, pol_act, &pr->rule) &&
 496                          ! try_rule(w, pol_domain, &pr->rule) &&
 497                          ! try_rule(w, pol_auto, &pr->rule))
 498                         pr_err("policy rule %s unrecognised and ignored\n",
 499                                 w);
 500         }
 501         pr->next = config_rules;
 502         config_rules = pr;
 503 }
 504
 505 void policy_add(char *type, ...)
 506 {
 507         va_list ap;
 508         struct pol_rule *pr;
 509         char *name, *val;
 510
 511         pr = xmalloc(sizeof(*pr));
 512         pr->type = type;
 513         pr->rule = NULL;
 514
 515         va_start(ap, type);
 516         while ((name = va_arg(ap, char*)) != NULL) {
 517                 struct rule *r;
 518
 519                 val = va_arg(ap, char*);
 520                 r = xmalloc(sizeof(*r));
 521                 r->next = pr->rule;
 522                 r->name = name;
 523                 r->value = xstrdup(val);
 524                 r->dups = NULL;
 525                 pr->rule = r;
 526         }
 527         pr->next = config_rules;
 528         config_rules = pr;
 529         va_end(ap);
 530 }
 531
 532 void policy_free(void)
 533 {
 534         while (config_rules) {
 535                 struct pol_rule *pr = config_rules;
 536                 struct rule *r;
 537
 538                 config_rules = config_rules->next;
 539
 540                 for (r = pr->rule; r; ) {
 541                         struct rule *next = r->next;
 542                         free(r->value);
 543                         if (r->dups)
 544                                 free_line(r->dups);
 545                         free(r);
 546                         r = next;
 547                 }
 548                 free(pr);
 549         }
 550         config_rules_end = NULL;
 551         config_rules_has_path = 0;
 552 }
 553
 554 void dev_policy_free(struct dev_policy *p)
 555 {
 556         struct dev_policy *t;
 557         while (p) {
 558                 t = p;
 559                 p = p->next;
 560                 free(t);
 561         }
 562 }
 563
 564 static enum policy_action map_act(const char *act)
 565 {
 566         if (strcmp(act, "include") == 0)
 567                 return act_include;
 568         if (strcmp(act, "re-add") == 0)
 569                 return act_re_add;
 570         if (strcmp(act, "spare") == 0)
 571                 return act_spare;
 572         if (strcmp(act, "spare-same-slot") == 0)
 573                 return act_spare_same_slot;
 574         if (strcmp(act, "force-spare") == 0)
 575                 return act_force_spare;
 576         return act_err;
 577 }
 578
 579 static enum policy_action policy_action(struct dev_policy *plist, const char *metadata)
 580 {
 581         enum policy_action rv = act_default;
 582         struct dev_policy *p;
 583
 584         plist = pol_find(plist, pol_act);
 585         pol_for_each(p, plist, metadata) {
 586                 enum policy_action a = map_act(p->value);
 587                 if (a > rv)
 588                         rv = a;
 589         }
 590         return rv;
 591 }
 592
 593 int policy_action_allows(struct dev_policy *plist, const char *metadata, enum policy_action want)
 594 {
 595         enum policy_action act = policy_action(plist, metadata);
 596
 597         if (act == act_err)
 598                 return 0;
 599         return (act >= want);
 600 }
 601
 602 int disk_action_allows(struct mdinfo *disk, const char *metadata, enum policy_action want)
 603 {
 604         struct dev_policy *pol = disk_policy(disk);
 605         int rv = policy_action_allows(pol, metadata, want);
 606
 607         dev_policy_free(pol);
 608         return rv;
 609 }
 610
 611 /* Domain policy:
 612  * Any device can have a list of domains asserted by different policy
 613  * statements.
 614  * An array also has a list of domains comprising all the domains of
 615  * all the devices in an array.
 616  * Where an array has a spare-group, that becomes an addition domain for
 617  * every device in the array and thus for the array.
 618  *
 619  * We keep the list of domains in a sorted linked list
 620  * As dev policies are already sorted, this is fairly easy to manage.
 621  */
 622
 623 static struct domainlist **domain_merge_one(struct domainlist **domp,
 624                                             const char *domain)
 625 {
 626         /* merge a domain name into a sorted list and return the
 627          * location of the insertion or match
 628          */
 629         struct domainlist *dom = *domp;
 630
 631         while (dom && strcmp(dom->dom, domain) < 0) {
 632                 domp = &dom->next;
 633                 dom = *domp;
 634         }
 635         if (dom == NULL || strcmp(dom->dom, domain) != 0) {
 636                 dom = xmalloc(sizeof(*dom));
 637                 dom->next = *domp;
 638                 dom->dom = domain;
 639                 *domp = dom;
 640         }
 641         return domp;
 642 }
 643
 644 #if (DEBUG)
 645 void dump_policy(struct dev_policy *policy)
 646 {
 647         while (policy) {
 648                 dprintf("policy: %p name: %s value: %s metadata: %s\n",
 649                         policy,
 650                         policy->name,
 651                         policy->value,
 652                         policy->metadata);
 653                 policy = policy->next;
 654         }
 655 }
 656 #endif
 657
 658 void domain_merge(struct domainlist **domp, struct dev_policy *pollist,
 659                          const char *metadata)
 660 {
 661         /* Add to 'domp' all the domains in pol that apply to 'metadata'
 662          * which are not already in domp
 663          */
 664         struct dev_policy *pol;
 665         pollist = pol_find(pollist, pol_domain);
 666         pol_for_each(pol, pollist, metadata)
 667                 domain_merge_one(domp, pol->value);
 668 }
 669
 670 int domain_test(struct domainlist *dom, struct dev_policy *pol,
 671                 const char *metadata)
 672 {
 673         /* Check that all domains in pol (for metadata) are also in
 674          * dom.  Both lists are sorted.
 675          * If pol has no domains, we don't really know about this device
 676          * so we allow caller to choose:
 677          * -1:  has no domains
 678          *  0:  has domains, not all match
 679          *  1:  has domains, all match
 680          */
 681         int found_any = -1;
 682         int has_one_domain = 1;
 683         struct dev_policy *p;
 684
 685         pol = pol_find(pol, pol_domain);
 686         pol_for_each(p, pol, metadata) {
 687                 found_any = 1;
 688                 while (dom && strcmp(dom->dom, p->value) < 0)
 689                         dom = dom->next;
 690                 if (!dom || strcmp(dom->dom, p->value) != 0)
 691                         return 0;
 692                 if (has_one_domain && metadata && strcmp(metadata, "imsm") == 0)
 693                         found_any = -1;
 694                 has_one_domain = 0;
 695         }
 696         return found_any;
 697 }
 698
 699 void domainlist_add_dev(struct domainlist **dom, int devid, const char *metadata)
 700 {
 701         struct dev_policy *pol = devid_policy(devid);
 702         domain_merge(dom, pol, metadata);
 703         dev_policy_free(pol);
 704 }
 705
 706 struct domainlist *domain_from_array(struct mdinfo *mdi, const char *metadata)
 707 {
 708         struct domainlist *domlist = NULL;
 709
 710         if (!mdi)
 711                 return NULL;
 712         for (mdi = mdi->devs ; mdi ; mdi = mdi->next)
 713                 domainlist_add_dev(&domlist, makedev(mdi->disk.major,
 714                                                      mdi->disk.minor),
 715                                    metadata);
 716
 717         return domlist;
 718 }
 719
 720 void domain_add(struct domainlist **domp, char *domain)
 721 {
 722         domain_merge_one(domp, domain);
 723 }
 724
 725 void domain_free(struct domainlist *dl)
 726 {
 727         while (dl) {
 728                 struct domainlist *head = dl;
 729                 dl = dl->next;
 730                 free(head);
 731         }
 732 }
 733
 734 /*
 735  * same-path policy.
 736  * Some policy decisions are guided by knowledge of which
 737  * array previously owned the device at a given physical location (path).
 738  * When removing a device from an array we might record the array against
 739  * the path, and when finding a new device, we might look for which
 740  * array previously used that path.
 741  *
 742  * The 'array' is described by a map_ent, and the path by a the disk in an
 743  * mdinfo, or a string.
 744  */
 745
 746 void policy_save_path(char *id_path, struct map_ent *array)
 747 {
 748         char path[PATH_MAX];
 749         FILE *f = NULL;
 750
 751         if (mkdir(FAILED_SLOTS_DIR, S_IRWXU) < 0 && errno != EEXIST) {
 752                 pr_err("can't create file to save path to old disk: %s\n", strerror(errno));
 753                 return;
 754         }
 755
 756         snprintf(path, PATH_MAX, FAILED_SLOTS_DIR "/%s", id_path);
 757         f = fopen(path, "w");
 758         if (!f) {
 759                 pr_err("can't create file to save path to old disk: %s\n",
 760                         strerror(errno));
 761                 return;
 762         }
 763
 764         if (fprintf(f, "%s %08x:%08x:%08x:%08x\n",
 765                     array->metadata,
 766                     array->uuid[0], array->uuid[1],
 767                     array->uuid[2], array->uuid[3]) <= 0)
 768                 pr_err("Failed to write to <id_path> cookie\n");
 769
 770         fclose(f);
 771 }
 772
 773 int policy_check_path(struct mdinfo *disk, struct map_ent *array)
 774 {
 775         char path[PATH_MAX];
 776         FILE *f = NULL;
 777         char **id_paths = disk_paths(disk);
 778         int i;
 779         int rv = 0;
 780
 781         for (i = 0; id_paths[i]; i++) {
 782                 snprintf(path, PATH_MAX, FAILED_SLOTS_DIR "/%s", id_paths[i]);
 783                 f = fopen(path, "r");
 784                 if (!f)
 785                         continue;
 786
 787                 rv = fscanf(f, " %s %x:%x:%x:%x\n",
 788                             array->metadata,
 789                             array->uuid,
 790                             array->uuid+1,
 791                             array->uuid+2,
 792                             array->uuid+3);
 793                 fclose(f);
 794                 break;
 795         }
 796         free_paths(id_paths);
 797         return rv == 5;
 798 }
 799
 800 /* invocation of udev rule file */
 801 char udev_template_start[] =
 802 "# do not edit this file, it is automatically generated by mdadm\n"
 803 "\n";
 804
 805 /* find rule named rule_type and return its value */
 806 char *find_rule(struct rule *rule, char *rule_type)
 807 {
 808         while (rule) {
 809                 if (rule->name == rule_type)
 810                         return rule->value;
 811
 812                 rule = rule->next;
 813         }
 814         return NULL;
 815 }
 816
 817 #define UDEV_RULE_FORMAT \
 818 "ACTION==\"add\", SUBSYSTEM==\"block\", " \
 819 "ENV{DEVTYPE}==\"%s\", ENV{ID_PATH}==\"%s\", " \
 820 "RUN+=\"" BINDIR "/mdadm --incremental $env{DEVNAME}\"\n"
 821
 822 #define UDEV_RULE_FORMAT_NOTYPE \
 823 "ACTION==\"add\", SUBSYSTEM==\"block\", " \
 824 "ENV{ID_PATH}==\"%s\", " \
 825 "RUN+=\"" BINDIR "/mdadm --incremental $env{DEVNAME}\"\n"
 826
 827 /* Write rule in the rule file. Use format from UDEV_RULE_FORMAT */
 828 int write_rule(struct rule *rule, int fd, int force_part)
 829 {
 830         char line[1024];
 831         char *pth = find_rule(rule, rule_path);
 832         char *typ = find_rule(rule, rule_type);
 833         if (!pth)
 834                 return -1;
 835
 836         if (force_part)
 837                 typ = type_part;
 838         if (typ)
 839                 snprintf(line, sizeof(line) - 1, UDEV_RULE_FORMAT, typ, pth);
 840         else
 841                 snprintf(line, sizeof(line) - 1, UDEV_RULE_FORMAT_NOTYPE, pth);
 842         return write(fd, line, strlen(line)) == (int)strlen(line);
 843 }
 844
 845 /* Generate single entry in udev rule basing on POLICY line found in config
 846  * file. Take only those with paths, only first occurrence if paths are equal
 847  * and if actions supports handling of spares (>=act_spare_same_slot)
 848  */
 849 int generate_entries(int fd)
 850 {
 851         struct pol_rule *loop, *dup;
 852         char *loop_value, *dup_value;
 853         int duplicate;
 854
 855         for (loop = config_rules; loop; loop = loop->next) {
 856                 if (loop->type != rule_policy && loop->type != rule_part)
 857                         continue;
 858                 duplicate = 0;
 859
 860                 /* only policies with paths and with actions supporting
 861                  * bare disks are considered */
 862                 loop_value = find_rule(loop->rule, pol_act);
 863                 if (!loop_value || map_act(loop_value) < act_spare_same_slot)
 864                         continue;
 865                 loop_value = find_rule(loop->rule, rule_path);
 866                 if (!loop_value)
 867                         continue;
 868                 for (dup = config_rules; dup != loop; dup = dup->next) {
 869                         if (dup->type != rule_policy && loop->type != rule_part)
 870                                 continue;
 871                         dup_value = find_rule(dup->rule, pol_act);
 872                         if (!dup_value || map_act(dup_value) < act_spare_same_slot)
 873                                 continue;
 874                         dup_value = find_rule(dup->rule, rule_path);
 875                         if (!dup_value)
 876                                 continue;
 877                         if (strcmp(loop_value, dup_value) == 0) {
 878                                 duplicate = 1;
 879                                 break;
 880                         }
 881                 }
 882
 883                 /* not a dup or first occurrence */
 884                 if (!duplicate)
 885                         if (!write_rule(loop->rule, fd, loop->type == rule_part) )
 886                                 return 0;
 887         }
 888         return 1;
 889 }
 890
 891 /* Write_rules routine creates dynamic udev rules used to handle
 892  * hot-plug events for bare devices (and making them spares)
 893  */
 894 int Write_rules(char *rule_name)
 895 {
 896         int fd;
 897         char udev_rule_file[PATH_MAX];
 898
 899         if (rule_name) {
 900                 strncpy(udev_rule_file, rule_name, sizeof(udev_rule_file) - 6);
 901                 udev_rule_file[sizeof(udev_rule_file) - 6] = '\0';
 902                 strcat(udev_rule_file, ".temp");
 903                 fd = creat(udev_rule_file,
 904                            S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
 905                 if (fd == -1)
 906                         return 1;
 907         } else
 908                 fd = 1;
 909
 910         /* write static invocation */
 911         if (write(fd, udev_template_start, sizeof(udev_template_start) - 1) !=
 912             (int)sizeof(udev_template_start) - 1)
 913                 goto abort;
 914
 915         /* iterate, if none created or error occurred, remove file */
 916         if (generate_entries(fd) < 0)
 917                 goto abort;
 918
 919         fsync(fd);
 920         if (rule_name) {
 921                 close(fd);
 922                 rename(udev_rule_file, rule_name);
 923         }
 924         return 0;
 925 abort:
 926         if (rule_name) {
 927                 close(fd);
 928                 unlink(udev_rule_file);
 929         }
 930         return 1;
 931 }