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 = malloc(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                                 fprintf(stderr, Name ": 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_path(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 nm[PATH_MAX];
 199         struct dirent *ent;
 200         int rv;
 201
 202         by_path = opendir(symlink);
 203         if (!by_path)
 204                 return NULL;
 205         prefix_len = strlen(symlink);
 206
 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                 closedir(by_path);
 220                 return strdup(ent->d_name);
 221         }
 222         closedir(by_path);
 223         /* A NULL path isn't really acceptable - use the devname.. */
 224         sprintf(symlink, "/sys/dev/block/%d:%d", disk->disk.major, disk->disk.minor);
 225         rv = readlink(symlink, nm, sizeof(nm)-1);
 226         if (rv > 0) {
 227                 char *dname;
 228                 nm[rv] = 0;
 229                 dname = strrchr(nm, '/');
 230                 if (dname)
 231                         return strdup(dname + 1);
 232         }
 233         return strdup("unknown");
 234 }
 235
 236 char type_part[] = "part";
 237 char type_disk[] = "disk";
 238 static char *disk_type(struct mdinfo *disk)
 239 {
 240         char buf[30+20+20];
 241         struct stat stb;
 242         sprintf(buf, "/sys/dev/block/%d:%d/partition",
 243                 disk->disk.major, disk->disk.minor);
 244         if (stat(buf, &stb) == 0)
 245                 return type_part;
 246         else
 247                 return type_disk;
 248 }
 249
 250 static int pol_match(struct rule *rule, char *path, char *type)
 251 {
 252         /* check if this rule matches on path and type */
 253         int pathok = 0; /* 0 == no path, 1 == match, -1 == no match yet */
 254         int typeok = 0;
 255
 256         while (rule) {
 257                 if (rule->name == rule_path) {
 258                         if (pathok == 0)
 259                                 pathok = -1;
 260                         if (path && fnmatch(rule->value, path, 0) == 0)
 261                                 pathok = 1;
 262                 }
 263                 if (rule->name == rule_type) {
 264                         if (typeok == 0)
 265                                 typeok = -1;
 266                         if (type && strcmp(rule->value, type) == 0)
 267                                 typeok = 1;
 268                 }
 269                 rule = rule->next;
 270         }
 271         return pathok >= 0 && typeok >= 0;
 272 }
 273
 274 static void pol_merge(struct dev_policy **pol, struct rule *rule)
 275 {
 276         /* copy any name assignments from rule into pol */
 277         struct rule *r;
 278         char *metadata = NULL;
 279         for (r = rule; r ; r = r->next)
 280                 if (r->name == pol_metadata)
 281                         metadata = r->value;
 282
 283         for (r = rule; r ; r = r->next)
 284                 if (r->name == pol_act ||
 285                     r->name == pol_domain ||
 286                     r->name == pol_auto)
 287                         pol_new(pol, r->name, r->value, metadata);
 288 }
 289
 290 static int path_has_part(char *path, char **part)
 291 {
 292         /* check if path ends with "-partNN" and
 293          * if it does, place a pointer to "-pathNN"
 294          * in 'part'.
 295          */
 296         int l;
 297         if (!path)
 298                 return 0;
 299         l = strlen(path);
 300         while (l > 1 && isdigit(path[l-1]))
 301                 l--;
 302         if (l < 5 || strncmp(path+l-5, "-part", 5) != 0)
 303                 return 0;
 304         *part = path+l-4;
 305         return 1;
 306 }
 307
 308 static void pol_merge_part(struct dev_policy **pol, struct rule *rule, char *part)
 309 {
 310         /* copy any name assignments from rule into pol, appending
 311          * -part to any domain.  The string with -part appended is
 312          * stored with the rule so it has a lifetime to match
 313          * the rule.
 314          */
 315         struct rule *r;
 316         char *metadata = NULL;
 317         for (r = rule; r ; r = r->next)
 318                 if (r->name == pol_metadata)
 319                         metadata = r->value;
 320
 321         for (r = rule; r ; r = r->next) {
 322                 if (r->name == pol_act)
 323                         pol_new(pol, r->name, r->value, metadata);
 324                 else if (r->name == pol_domain) {
 325                         char *dom;
 326                         int len;
 327                         if (r->dups == NULL)
 328                                 r->dups = dl_head();
 329                         len = strlen(r->value);
 330                         for (dom = dl_next(r->dups); dom != r->dups;
 331                              dom = dl_next(dom))
 332                                 if (strcmp(dom+len+1, part)== 0)
 333                                         break;
 334                         if (dom == r->dups) {
 335                                 char *newdom = dl_strndup(
 336                                         r->value, len + 1 + strlen(part));
 337                                 strcat(strcat(newdom, "-"), part);
 338                                 dl_add(r->dups, newdom);
 339                                 dom = newdom;
 340                         }
 341                         pol_new(pol, r->name, dom, metadata);
 342                 }
 343         }
 344 }
 345
 346 static struct pol_rule *config_rules = NULL;
 347 static struct pol_rule **config_rules_end = NULL;
 348 static int config_rules_has_path = 0;
 349
 350 /*
 351  * most policy comes from a set policy rules that are
 352  * read from the config file.
 353  * path_policy() gathers policy information for the
 354  * disk described in the given a 'path' and a 'type'.
 355  */
 356 struct dev_policy *path_policy(char *path, char *type)
 357 {
 358         struct pol_rule *rules;
 359         struct dev_policy *pol = NULL;
 360         int i;
 361
 362         rules = config_rules;
 363
 364         while (rules) {
 365                 char *part;
 366                 if (rules->type == rule_policy)
 367                         if (pol_match(rules->rule, path, type))
 368                                 pol_merge(&pol, rules->rule);
 369                 if (rules->type == rule_part && strcmp(type, type_part) == 0)
 370                         if (path_has_part(path, &part)) {
 371                                 *part = 0;
 372                                 if (pol_match(rules->rule, path, type_disk))
 373                                         pol_merge_part(&pol, rules->rule, part+1);
 374                                 *part = '-';
 375                         }
 376                 rules = rules->next;
 377         }
 378
 379         /* Now add any metadata-specific internal knowledge
 380          * about this path
 381          */
 382         for (i=0; path && superlist[i]; i++)
 383                 if (superlist[i]->get_disk_controller_domain) {
 384                         const char *d =
 385                                 superlist[i]->get_disk_controller_domain(path);
 386                         if (d)
 387                                 pol_new(&pol, pol_domain, d, superlist[i]->name);
 388                 }
 389
 390         pol_sort(&pol);
 391         pol_dedup(pol);
 392         return pol;
 393 }
 394
 395 void pol_add(struct dev_policy **pol,
 396                     char *name, char *val,
 397                     char *metadata)
 398 {
 399         pol_new(pol, name, val, metadata);
 400         pol_sort(pol);
 401         pol_dedup(*pol);
 402 }
 403
 404
 405 /*
 406  * disk_policy() gathers policy information for the
 407  * disk described in the given mdinfo (disk.{major,minor}).
 408  */
 409 struct dev_policy *disk_policy(struct mdinfo *disk)
 410 {
 411         char *path = NULL;
 412         char *type = disk_type(disk);
 413         struct dev_policy *pol = NULL;
 414
 415         if (config_rules_has_path)
 416                 path = disk_path(disk);
 417
 418         pol = path_policy(path, type);
 419
 420         free(path);
 421         return pol;
 422 }
 423
 424 struct dev_policy *devnum_policy(int dev)
 425 {
 426         struct mdinfo disk;
 427         disk.disk.major = major(dev);
 428         disk.disk.minor = minor(dev);
 429         return disk_policy(&disk);
 430 }
 431
 432 /*
 433  * process policy rules read from config file.
 434  */
 435
 436 char rule_path[] = "path";
 437 char rule_type[] = "type";
 438
 439 char rule_policy[] = "policy";
 440 char rule_part[] = "part-policy";
 441
 442 char pol_metadata[] = "metadata";
 443 char pol_act[] = "action";
 444 char pol_domain[] = "domain";
 445 char pol_auto[] = "auto";
 446
 447 static int try_rule(char *w, char *name, struct rule **rp)
 448 {
 449         struct rule *r;
 450         int len = strlen(name);
 451         if (strncmp(w, name, len) != 0 ||
 452             w[len] != '=')
 453                 return 0;
 454         r = malloc(sizeof(*r));
 455         r->next = *rp;
 456         r->name = name;
 457         r->value = strdup(w+len+1);
 458         r->dups = NULL;
 459         *rp = r;
 460         return 1;
 461 }
 462
 463 void policyline(char *line, char *type)
 464 {
 465         struct pol_rule *pr;
 466         char *w;
 467
 468         if (config_rules_end == NULL)
 469                 config_rules_end = &config_rules;
 470
 471         pr = malloc(sizeof(*pr));
 472         pr->type = type;
 473         pr->rule = NULL;
 474         for (w = dl_next(line); w != line ; w = dl_next(w)) {
 475                 if (try_rule(w, rule_path, &pr->rule))
 476                         config_rules_has_path = 1;
 477                 else if (! try_rule(w, rule_type, &pr->rule) &&
 478                          ! try_rule(w, pol_metadata, &pr->rule) &&
 479                          ! try_rule(w, pol_act, &pr->rule) &&
 480                          ! try_rule(w, pol_domain, &pr->rule) &&
 481                          ! try_rule(w, pol_auto, &pr->rule))
 482                         fprintf(stderr, Name ": policy rule %s unrecognised and ignored\n",
 483                                 w);
 484         }
 485         pr->next = config_rules;
 486         config_rules = pr;
 487 }
 488
 489 void policy_add(char *type, ...)
 490 {
 491         va_list ap;
 492         struct pol_rule *pr;
 493         char *name, *val;
 494
 495         pr = malloc(sizeof(*pr));
 496         pr->type = type;
 497         pr->rule = NULL;
 498
 499         va_start(ap, type);
 500         while ((name = va_arg(ap, char*)) != NULL) {
 501                 struct rule *r;
 502
 503                 val = va_arg(ap, char*);
 504                 r = malloc(sizeof(*r));
 505                 r->next = pr->rule;
 506                 r->name = name;
 507                 r->value = strdup(val);
 508                 r->dups = NULL;
 509                 pr->rule = r;
 510         }
 511         pr->next = config_rules;
 512         config_rules = pr;
 513 }
 514
 515 void policy_free(void)
 516 {
 517         while (config_rules) {
 518                 struct pol_rule *pr = config_rules;
 519                 struct rule *r;
 520
 521                 config_rules = config_rules->next;
 522
 523                 for (r = pr->rule; r; ) {
 524                         struct rule *next = r->next;
 525                         free(r->value);
 526                         if (r->dups)
 527                                 free_line(r->dups);
 528                         free(r);
 529                         r = next;
 530                 }
 531                 free(pr);
 532         }
 533         config_rules_end = NULL;
 534         config_rules_has_path = 0;
 535 }
 536
 537 void dev_policy_free(struct dev_policy *p)
 538 {
 539         struct dev_policy *t;
 540         while (p) {
 541                 t = p;
 542                 p = p->next;
 543                 free(t);
 544         }
 545 }
 546
 547 static enum policy_action map_act(const char *act)
 548 {
 549         if (strcmp(act, "include") == 0)
 550                 return act_include;
 551         if (strcmp(act, "re-add") == 0)
 552                 return act_re_add;
 553         if (strcmp(act, "spare") == 0)
 554                 return act_spare;
 555         if (strcmp(act, "spare-same-slot") == 0)
 556                 return act_spare_same_slot;
 557         if (strcmp(act, "force-spare") == 0)
 558                 return act_force_spare;
 559         return act_err;
 560 }
 561
 562 static enum policy_action policy_action(struct dev_policy *plist, const char *metadata)
 563 {
 564         enum policy_action rv = act_default;
 565         struct dev_policy *p;
 566
 567         plist = pol_find(plist, pol_act);
 568         pol_for_each(p, plist, metadata) {
 569                 enum policy_action a = map_act(p->value);
 570                 if (a > rv)
 571                         rv = a;
 572         }
 573         return rv;
 574 }
 575
 576 int policy_action_allows(struct dev_policy *plist, const char *metadata, enum policy_action want)
 577 {
 578         enum policy_action act = policy_action(plist, metadata);
 579
 580         if (act == act_err)
 581                 return 0;
 582         return (act >= want);
 583 }
 584
 585 int disk_action_allows(struct mdinfo *disk, const char *metadata, enum policy_action want)
 586 {
 587         struct dev_policy *pol = disk_policy(disk);
 588         int rv = policy_action_allows(pol, metadata, want);
 589
 590         dev_policy_free(pol);
 591         return rv;
 592 }
 593
 594
 595 /* Domain policy:
 596  * Any device can have a list of domains asserted by different policy
 597  * statements.
 598  * An array also has a list of domains comprising all the domains of
 599  * all the devices in an array.
 600  * Where an array has a spare-group, that becomes an addition domain for
 601  * every device in the array and thus for the array.
 602  *
 603  * We keep the list of domains in a sorted linked list
 604  * As dev policies are already sorted, this is fairly easy to manage.
 605  */
 606
 607 static struct domainlist **domain_merge_one(struct domainlist **domp,
 608                                             const char *domain)
 609 {
 610         /* merge a domain name into a sorted list and return the
 611          * location of the insertion or match
 612          */
 613         struct domainlist *dom = *domp;
 614
 615         while (dom && strcmp(dom->dom, domain) < 0) {
 616                 domp = &dom->next;
 617                 dom = *domp;
 618         }
 619         if (dom == NULL || strcmp(dom->dom, domain) != 0) {
 620                 dom = malloc(sizeof(*dom));
 621                 dom->next = *domp;
 622                 dom->dom = domain;
 623                 *domp = dom;
 624         }
 625         return domp;
 626 }
 627
 628 #if (DEBUG)
 629 void dump_policy(struct dev_policy *policy)
 630 {
 631         while (policy) {
 632                 dprintf("policy: %p name: %s value: %s metadata: %s\n",
 633                         policy,
 634                         policy->name,
 635                         policy->value,
 636                         policy->metadata);
 637                 policy = policy->next;
 638         }
 639 }
 640 #endif
 641
 642 void domain_merge(struct domainlist **domp, struct dev_policy *pollist,
 643                          const char *metadata)
 644 {
 645         /* Add to 'domp' all the domains in pol that apply to 'metadata'
 646          * which are not already in domp
 647          */
 648         struct dev_policy *pol;
 649         pollist = pol_find(pollist, pol_domain);
 650         pol_for_each(pol, pollist, metadata)
 651                 domain_merge_one(domp, pol->value);
 652 }
 653
 654 int domain_test(struct domainlist *dom, struct dev_policy *pol,
 655                 const char *metadata)
 656 {
 657         /* Check that all domains in pol (for metadata) are also in
 658          * dom.  Both lists are sorted.
 659          * If pol has no domains, we don't really know about this device
 660          * so we allow caller to choose:
 661          * -1:  has no domains
 662          *  0:  has domains, not all match
 663          *  1:  has domains, all match
 664          */
 665         int found_any = -1;
 666         struct dev_policy *p;
 667
 668         pol = pol_find(pol, pol_domain);
 669         pol_for_each(p, pol, metadata) {
 670                 found_any = 1;
 671                 while (dom && strcmp(dom->dom, p->value) < 0)
 672                         dom = dom->next;
 673                 if (!dom || strcmp(dom->dom, p->value) != 0)
 674                         return 0;
 675         }
 676         return found_any;
 677 }
 678
 679 void domainlist_add_dev(struct domainlist **dom, int devnum, const char *metadata)
 680 {
 681         struct dev_policy *pol = devnum_policy(devnum);
 682         domain_merge(dom, pol, metadata);
 683         dev_policy_free(pol);
 684 }
 685
 686 struct domainlist *domain_from_array(struct mdinfo *mdi, const char *metadata)
 687 {
 688         struct domainlist *domlist = NULL;
 689
 690         if (!mdi)
 691                 return NULL;
 692         for (mdi = mdi->devs ; mdi ; mdi = mdi->next)
 693                 domainlist_add_dev(&domlist, makedev(mdi->disk.major,
 694                                                      mdi->disk.minor),
 695                                    metadata);
 696
 697         return domlist;
 698 }
 699
 700 void domain_add(struct domainlist **domp, char *domain)
 701 {
 702         domain_merge_one(domp, domain);
 703 }
 704
 705
 706 void domain_free(struct domainlist *dl)
 707 {
 708         while (dl) {
 709                 struct domainlist *head = dl;
 710                 dl = dl->next;
 711                 free(head);
 712         }
 713 }
 714
 715 /*
 716  * same-path policy.
 717  * Some policy decisions are guided by knowledge of which
 718  * array previously owned the device at a given physical location (path).
 719  * When removing a device from an array we might record the array against
 720  * the path, and when finding a new device, we might look for which
 721  * array previously used that path.
 722  *
 723  * The 'array' is described by a map_ent, and the path by a the disk in an
 724  * mdinfo, or a string.
 725  */
 726
 727 void policy_save_path(char *id_path, struct map_ent *array)
 728 {
 729         char path[PATH_MAX];
 730         FILE *f = NULL;
 731
 732         if (mkdir(FAILED_SLOTS_DIR, S_IRWXU) < 0 && errno != EEXIST) {
 733                 fprintf(stderr, Name ": can't create file to save path "
 734                         "to old disk: %s\n", strerror(errno));
 735                 return;
 736         }
 737
 738         snprintf(path, PATH_MAX, FAILED_SLOTS_DIR "/%s", id_path);
 739         f = fopen(path, "w");
 740         if (!f) {
 741                 fprintf(stderr, Name ": can't create file to"
 742                         " save path to old disk: %s\n",
 743                         strerror(errno));
 744                 return;
 745         }
 746
 747         if (fprintf(f, "%s %08x:%08x:%08x:%08x\n",
 748                     array->metadata,
 749                     array->uuid[0], array->uuid[1],
 750                     array->uuid[2], array->uuid[3]) <= 0)
 751                 fprintf(stderr, Name ": Failed to write to "
 752                         "<id_path> cookie\n");
 753
 754         fclose(f);
 755 }
 756
 757 int policy_check_path(struct mdinfo *disk, struct map_ent *array)
 758 {
 759         char path[PATH_MAX];
 760         FILE *f = NULL;
 761         char *id_path = disk_path(disk);
 762         int rv;
 763
 764         if (!id_path)
 765                 return 0;
 766
 767         snprintf(path, PATH_MAX, FAILED_SLOTS_DIR "/%s", id_path);
 768         f = fopen(path, "r");
 769         if (!f) {
 770                 free(id_path);
 771                 return 0;
 772         }
 773
 774         rv = fscanf(f, " %s %x:%x:%x:%x\n",
 775                     array->metadata,
 776                     array->uuid,
 777                     array->uuid+1,
 778                     array->uuid+2,
 779                     array->uuid+3);
 780         fclose(f);
 781         free(id_path);
 782         return rv == 5;
 783 }
 784
 785 /* invocation of udev rule file */
 786 char udev_template_start[] =
 787 "# do not edit this file, it is automatically generated by mdadm\n"
 788 "\n";
 789
 790 /* find rule named rule_type and return its value */
 791 char *find_rule(struct rule *rule, char *rule_type)
 792 {
 793        while (rule) {
 794                if (rule->name == rule_type)
 795                        return rule->value;
 796
 797                rule = rule->next;
 798        }
 799        return NULL;
 800 }
 801
 802 #define UDEV_RULE_FORMAT \
 803 "ACTION==\"add\", SUBSYSTEM==\"block\", " \
 804 "ENV{DEVTYPE}==\"%s\", ENV{ID_PATH}==\"%s\", " \
 805 "RUN+=\"/sbin/mdadm --incremental $env{DEVNAME}\"\n"
 806
 807 #define UDEV_RULE_FORMAT_NOTYPE \
 808 "ACTION==\"add\", SUBSYSTEM==\"block\", " \
 809 "ENV{ID_PATH}==\"%s\", " \
 810 "RUN+=\"/sbin/mdadm --incremental $env{DEVNAME}\"\n"
 811
 812 /* Write rule in the rule file. Use format from UDEV_RULE_FORMAT */
 813 int write_rule(struct rule *rule, int fd, int force_part)
 814 {
 815         char line[1024];
 816         char *pth = find_rule(rule, rule_path);
 817         char *typ = find_rule(rule, rule_type);
 818         if (!pth)
 819                 return -1;
 820
 821         if (force_part)
 822                 typ = type_part;
 823         if (typ)
 824                 snprintf(line, sizeof(line) - 1, UDEV_RULE_FORMAT, typ, pth);
 825         else
 826                 snprintf(line, sizeof(line) - 1, UDEV_RULE_FORMAT_NOTYPE, pth);
 827         return write(fd, line, strlen(line)) == (int)strlen(line);
 828 }
 829
 830 /* Generate single entry in udev rule basing on POLICY line found in config
 831  * file. Take only those with paths, only first occurrence if paths are equal
 832  * and if actions supports handling of spares (>=act_spare_same_slot)
 833  */
 834 int generate_entries(int fd)
 835 {
 836        struct pol_rule *loop, *dup;
 837        char *loop_value, *dup_value;
 838        int duplicate;
 839
 840        for (loop = config_rules; loop; loop = loop->next) {
 841                if (loop->type != rule_policy && loop->type != rule_part)
 842                        continue;
 843                duplicate = 0;
 844
 845                /* only policies with paths and with actions supporting
 846                 * bare disks are considered */
 847                loop_value = find_rule(loop->rule, pol_act);
 848                if (!loop_value || map_act(loop_value) < act_spare_same_slot)
 849                        continue;
 850                loop_value = find_rule(loop->rule, rule_path);
 851                if (!loop_value)
 852                        continue;
 853                for (dup = config_rules; dup != loop; dup = dup->next) {
 854                        if (dup->type != rule_policy && loop->type != rule_part)
 855                                continue;
 856                        dup_value = find_rule(dup->rule, pol_act);
 857                        if (!dup_value || map_act(dup_value) < act_spare_same_slot)
 858                                continue;
 859                        dup_value = find_rule(dup->rule, rule_path);
 860                        if (!dup_value)
 861                                continue;
 862                        if (strcmp(loop_value, dup_value) == 0) {
 863                                duplicate = 1;
 864                                break;
 865                        }
 866                }
 867
 868                /* not a dup or first occurrence */
 869                if (!duplicate)
 870                        if (!write_rule(loop->rule, fd, loop->type == rule_part) )
 871                                return 0;
 872        }
 873        return 1;
 874 }
 875
 876 /* Write_rules routine creates dynamic udev rules used to handle
 877  * hot-plug events for bare devices (and making them spares)
 878  */
 879 int Write_rules(char *rule_name)
 880 {
 881        int fd;
 882        char udev_rule_file[PATH_MAX];
 883
 884        if (rule_name) {
 885                strcpy(udev_rule_file, rule_name);
 886                strcat(udev_rule_file, ".temp");
 887                fd = creat(udev_rule_file,
 888                           S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
 889                if (fd == -1)
 890                        return 1;
 891        } else
 892                fd = 1;
 893
 894        /* write static invocation */
 895        if (write(fd, udev_template_start,
 896                  sizeof(udev_template_start) - 1)
 897            != (int)sizeof(udev_template_start)-1)
 898                goto abort;
 899
 900        /* iterate, if none created or error occurred, remove file */
 901        if (generate_entries(fd) < 0)
 902                goto abort;
 903
 904        fsync(fd);
 905        if (rule_name) {
 906                close(fd);
 907                rename(udev_rule_file, rule_name);
 908        }
 909        return 0;
 910 abort:
 911        if (rule_name) {
 912                close(fd);
 913                unlink(udev_rule_file);
 914        }
 915        return 1;
 916 }