src/libudev/libudev-enumerate.c

   1 /*
   2  * libudev - interface to udev device information
   3  *
   4  * Copyright (C) 2008-2010 Kay Sievers <kay.sievers@vrfy.org>
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  */
  11
  12 #include <stdio.h>
  13 #include <stdlib.h>
  14 #include <stddef.h>
  15 #include <unistd.h>
  16 #include <errno.h>
  17 #include <string.h>
  18 #include <dirent.h>
  19 #include <fnmatch.h>
  20 #include <stdbool.h>
  21 #include <sys/stat.h>
  22 #include <sys/param.h>
  23
  24 #include "libudev.h"
  25 #include "libudev-private.h"
  26
  27 /**
  28  * SECTION:libudev-enumerate
  29  * @short_description: lookup and sort sys devices
  30  *
  31  * Lookup devices in the sys filesystem, filter devices by properties,
  32  * and return a sorted list of devices.
  33  */
  34
  35 struct syspath {
  36         char *syspath;
  37         size_t len;
  38 };
  39
  40 /**
  41  * udev_enumerate:
  42  *
  43  * Opaque object representing one device lookup/sort context.
  44  */
  45 struct udev_enumerate {
  46         struct udev *udev;
  47         int refcount;
  48         struct udev_list sysattr_match_list;
  49         struct udev_list sysattr_nomatch_list;
  50         struct udev_list subsystem_match_list;
  51         struct udev_list subsystem_nomatch_list;
  52         struct udev_list sysname_match_list;
  53         struct udev_list properties_match_list;
  54         struct udev_list tags_match_list;
  55         struct udev_device *parent_match;
  56         struct udev_list devices_list;
  57         struct syspath *devices;
  58         unsigned int devices_cur;
  59         unsigned int devices_max;
  60         bool devices_uptodate:1;
  61         bool match_is_initialized;
  62 };
  63
  64 /**
  65  * udev_enumerate_new:
  66  * @udev: udev library context
  67  *
  68  * Create an enumeration context to scan /sys.
  69  *
  70  * Returns: an enumeration context.
  71  **/
  72 _public_ struct udev_enumerate *udev_enumerate_new(struct udev *udev)
  73 {
  74         struct udev_enumerate *udev_enumerate;
  75
  76         udev_enumerate = calloc(1, sizeof(struct udev_enumerate));
  77         if (udev_enumerate == NULL)
  78                 return NULL;
  79         udev_enumerate->refcount = 1;
  80         udev_enumerate->udev = udev;
  81         udev_list_init(udev, &udev_enumerate->sysattr_match_list, false);
  82         udev_list_init(udev, &udev_enumerate->sysattr_nomatch_list, false);
  83         udev_list_init(udev, &udev_enumerate->subsystem_match_list, true);
  84         udev_list_init(udev, &udev_enumerate->subsystem_nomatch_list, true);
  85         udev_list_init(udev, &udev_enumerate->sysname_match_list, true);
  86         udev_list_init(udev, &udev_enumerate->properties_match_list, false);
  87         udev_list_init(udev, &udev_enumerate->tags_match_list, true);
  88         udev_list_init(udev, &udev_enumerate->devices_list, false);
  89         return udev_enumerate;
  90 }
  91
  92 /**
  93  * udev_enumerate_ref:
  94  * @udev_enumerate: context
  95  *
  96  * Take a reference of a enumeration context.
  97  *
  98  * Returns: the passed enumeration context
  99  **/
 100 _public_ struct udev_enumerate *udev_enumerate_ref(struct udev_enumerate *udev_enumerate)
 101 {
 102         if (udev_enumerate == NULL)
 103                 return NULL;
 104         udev_enumerate->refcount++;
 105         return udev_enumerate;
 106 }
 107
 108 /**
 109  * udev_enumerate_unref:
 110  * @udev_enumerate: context
 111  *
 112  * Drop a reference of an enumeration context. If the refcount reaches zero,
 113  * all resources of the enumeration context will be released.
 114  *
 115  * Returns: the passed enumeration context if it has still an active reference, or #NULL otherwise.
 116  **/
 117 _public_ struct udev_enumerate *udev_enumerate_unref(struct udev_enumerate *udev_enumerate)
 118 {
 119         unsigned int i;
 120
 121         if (udev_enumerate == NULL)
 122                 return NULL;
 123         udev_enumerate->refcount--;
 124         if (udev_enumerate->refcount > 0)
 125                 return udev_enumerate;
 126         udev_list_cleanup(&udev_enumerate->sysattr_match_list);
 127         udev_list_cleanup(&udev_enumerate->sysattr_nomatch_list);
 128         udev_list_cleanup(&udev_enumerate->subsystem_match_list);
 129         udev_list_cleanup(&udev_enumerate->subsystem_nomatch_list);
 130         udev_list_cleanup(&udev_enumerate->sysname_match_list);
 131         udev_list_cleanup(&udev_enumerate->properties_match_list);
 132         udev_list_cleanup(&udev_enumerate->tags_match_list);
 133         udev_device_unref(udev_enumerate->parent_match);
 134         udev_list_cleanup(&udev_enumerate->devices_list);
 135         for (i = 0; i < udev_enumerate->devices_cur; i++)
 136                 free(udev_enumerate->devices[i].syspath);
 137         free(udev_enumerate->devices);
 138         free(udev_enumerate);
 139         return NULL;
 140 }
 141
 142 /**
 143  * udev_enumerate_get_udev:
 144  * @udev_enumerate: context
 145  *
 146  * Get the udev library context.
 147  *
 148  * Returns: a pointer to the context.
 149  */
 150 _public_ struct udev *udev_enumerate_get_udev(struct udev_enumerate *udev_enumerate)
 151 {
 152         if (udev_enumerate == NULL)
 153                 return NULL;
 154         return udev_enumerate->udev;
 155 }
 156
 157 static int syspath_add(struct udev_enumerate *udev_enumerate, const char *syspath)
 158 {
 159         char *path;
 160         struct syspath *entry;
 161
 162         /* double array size if needed */
 163         if (udev_enumerate->devices_cur >= udev_enumerate->devices_max) {
 164                 struct syspath *buf;
 165                 unsigned int add;
 166
 167                 add = udev_enumerate->devices_max;
 168                 if (add < 1024)
 169                         add = 1024;
 170                 buf = realloc(udev_enumerate->devices, (udev_enumerate->devices_max + add) * sizeof(struct syspath));
 171                 if (buf == NULL)
 172                         return -ENOMEM;
 173                 udev_enumerate->devices = buf;
 174                 udev_enumerate->devices_max += add;
 175         }
 176
 177         path = strdup(syspath);
 178         if (path == NULL)
 179                 return -ENOMEM;
 180         entry = &udev_enumerate->devices[udev_enumerate->devices_cur];
 181         entry->syspath = path;
 182         entry->len = strlen(path);
 183         udev_enumerate->devices_cur++;
 184         udev_enumerate->devices_uptodate = false;
 185         return 0;
 186 }
 187
 188 static int syspath_cmp(const void *p1, const void *p2)
 189 {
 190         const struct syspath *path1 = p1;
 191         const struct syspath *path2 = p2;
 192         size_t len;
 193         int ret;
 194
 195         len = MIN(path1->len, path2->len);
 196         ret = memcmp(path1->syspath, path2->syspath, len);
 197         if (ret == 0) {
 198                 if (path1->len < path2->len)
 199                         ret = -1;
 200                 else if (path1->len > path2->len)
 201                         ret = 1;
 202         }
 203         return ret;
 204 }
 205
 206 /* For devices that should be moved to the absolute end of the list */
 207 static bool devices_delay_end(struct udev *udev, const char *syspath)
 208 {
 209         static const char *delay_device_list[] = {
 210                 "/block/md",
 211                 "/block/dm-",
 212                 NULL
 213         };
 214         int i;
 215
 216         for (i = 0; delay_device_list[i] != NULL; i++) {
 217                 if (strstr(syspath + strlen("/sys"), delay_device_list[i]) != NULL)
 218                         return true;
 219         }
 220         return false;
 221 }
 222
 223 /* For devices that should just be moved a little bit later, just
 224  * before the point where some common path prefix changes. Returns the
 225  * number of characters that make up that common prefix */
 226 static size_t devices_delay_later(struct udev *udev, const char *syspath)
 227 {
 228         const char *c;
 229
 230         /* For sound cards the control device must be enumerated last
 231          * to make sure it's the final device node that gets ACLs
 232          * applied. Applications rely on this fact and use ACL changes
 233          * on the control node as an indicator that the ACL change of
 234          * the entire sound card completed. The kernel makes this
 235          * guarantee when creating those devices, and hence we should
 236          * too when enumerating them. */
 237
 238         if ((c = strstr(syspath, "/sound/card"))) {
 239                 c += 11;
 240                 c += strcspn(c, "/");
 241
 242                 if (startswith(c, "/controlC"))
 243                         return c - syspath + 1;
 244         }
 245
 246         return 0;
 247 }
 248
 249 /**
 250  * udev_enumerate_get_list_entry:
 251  * @udev_enumerate: context
 252  *
 253  * Get the first entry of the sorted list of device paths.
 254  *
 255  * Returns: a udev_list_entry.
 256  */
 257 _public_ struct udev_list_entry *udev_enumerate_get_list_entry(struct udev_enumerate *udev_enumerate)
 258 {
 259         if (udev_enumerate == NULL)
 260                 return NULL;
 261         if (!udev_enumerate->devices_uptodate) {
 262                 unsigned int i;
 263                 unsigned int max;
 264                 struct syspath *prev = NULL, *move_later = NULL;
 265                 size_t move_later_prefix = 0;
 266
 267                 udev_list_cleanup(&udev_enumerate->devices_list);
 268                 qsort(udev_enumerate->devices, udev_enumerate->devices_cur, sizeof(struct syspath), syspath_cmp);
 269
 270                 max = udev_enumerate->devices_cur;
 271                 for (i = 0; i < max; i++) {
 272                         struct syspath *entry = &udev_enumerate->devices[i];
 273
 274                         /* skip duplicated entries */
 275                         if (prev != NULL &&
 276                             entry->len == prev->len &&
 277                             memcmp(entry->syspath, prev->syspath, entry->len) == 0)
 278                                 continue;
 279                         prev = entry;
 280
 281                         /* skip to be delayed devices, and add them to the end of the list */
 282                         if (devices_delay_end(udev_enumerate->udev, entry->syspath)) {
 283                                 syspath_add(udev_enumerate, entry->syspath);
 284                                 /* need to update prev here for the case realloc() gives a different address */
 285                                 prev = &udev_enumerate->devices[i];
 286                                 continue;
 287                         }
 288
 289                         /* skip to be delayed devices, and move the to
 290                          * the point where the prefix changes. We can
 291                          * only move one item at a time. */
 292                         if (!move_later) {
 293                                 move_later_prefix = devices_delay_later(udev_enumerate->udev, entry->syspath);
 294
 295                                 if (move_later_prefix > 0) {
 296                                         move_later = entry;
 297                                         continue;
 298                                 }
 299                         }
 300
 301                         if (move_later &&
 302                             strncmp(entry->syspath, move_later->syspath, move_later_prefix) != 0) {
 303
 304                                 udev_list_entry_add(&udev_enumerate->devices_list, move_later->syspath, NULL);
 305                                 move_later = NULL;
 306                         }
 307
 308                         udev_list_entry_add(&udev_enumerate->devices_list, entry->syspath, NULL);
 309                 }
 310
 311                 if (move_later)
 312                         udev_list_entry_add(&udev_enumerate->devices_list, move_later->syspath, NULL);
 313
 314                 /* add and cleanup delayed devices from end of list */
 315                 for (i = max; i < udev_enumerate->devices_cur; i++) {
 316                         struct syspath *entry = &udev_enumerate->devices[i];
 317
 318                         udev_list_entry_add(&udev_enumerate->devices_list, entry->syspath, NULL);
 319                         free(entry->syspath);
 320                 }
 321                 udev_enumerate->devices_cur = max;
 322
 323                 udev_enumerate->devices_uptodate = true;
 324         }
 325         return udev_list_get_entry(&udev_enumerate->devices_list);
 326 }
 327
 328 /**
 329  * udev_enumerate_add_match_subsystem:
 330  * @udev_enumerate: context
 331  * @subsystem: filter for a subsystem of the device to include in the list
 332  *
 333  * Match only devices belonging to a certain kernel subsystem.
 334  *
 335  * Returns: 0 on success, otherwise a negative error value.
 336  */
 337 _public_ int udev_enumerate_add_match_subsystem(struct udev_enumerate *udev_enumerate, const char *subsystem)
 338 {
 339         if (udev_enumerate == NULL)
 340                 return -EINVAL;
 341         if (subsystem == NULL)
 342                 return 0;
 343         if (udev_list_entry_add(&udev_enumerate->subsystem_match_list, subsystem, NULL) == NULL)
 344                 return -ENOMEM;
 345         return 0;
 346 }
 347
 348 /**
 349  * udev_enumerate_add_nomatch_subsystem:
 350  * @udev_enumerate: context
 351  * @subsystem: filter for a subsystem of the device to exclude from the list
 352  *
 353  * Match only devices not belonging to a certain kernel subsystem.
 354  *
 355  * Returns: 0 on success, otherwise a negative error value.
 356  */
 357 _public_ int udev_enumerate_add_nomatch_subsystem(struct udev_enumerate *udev_enumerate, const char *subsystem)
 358 {
 359         if (udev_enumerate == NULL)
 360                 return -EINVAL;
 361         if (subsystem == NULL)
 362                 return 0;
 363         if (udev_list_entry_add(&udev_enumerate->subsystem_nomatch_list, subsystem, NULL) == NULL)
 364                 return -ENOMEM;
 365         return 0;
 366 }
 367
 368 /**
 369  * udev_enumerate_add_match_sysattr:
 370  * @udev_enumerate: context
 371  * @sysattr: filter for a sys attribute at the device to include in the list
 372  * @value: optional value of the sys attribute
 373  *
 374  * Match only devices with a certain /sys device attribute.
 375  *
 376  * Returns: 0 on success, otherwise a negative error value.
 377  */
 378 _public_ int udev_enumerate_add_match_sysattr(struct udev_enumerate *udev_enumerate, const char *sysattr, const char *value)
 379 {
 380         if (udev_enumerate == NULL)
 381                 return -EINVAL;
 382         if (sysattr == NULL)
 383                 return 0;
 384         if (udev_list_entry_add(&udev_enumerate->sysattr_match_list, sysattr, value) == NULL)
 385                 return -ENOMEM;
 386         return 0;
 387 }
 388
 389 /**
 390  * udev_enumerate_add_nomatch_sysattr:
 391  * @udev_enumerate: context
 392  * @sysattr: filter for a sys attribute at the device to exclude from the list
 393  * @value: optional value of the sys attribute
 394  *
 395  * Match only devices not having a certain /sys device attribute.
 396  *
 397  * Returns: 0 on success, otherwise a negative error value.
 398  */
 399 _public_ int udev_enumerate_add_nomatch_sysattr(struct udev_enumerate *udev_enumerate, const char *sysattr, const char *value)
 400 {
 401         if (udev_enumerate == NULL)
 402                 return -EINVAL;
 403         if (sysattr == NULL)
 404                 return 0;
 405         if (udev_list_entry_add(&udev_enumerate->sysattr_nomatch_list, sysattr, value) == NULL)
 406                 return -ENOMEM;
 407         return 0;
 408 }
 409
 410 static int match_sysattr_value(struct udev_device *dev, const char *sysattr, const char *match_val)
 411 {
 412         const char *val = NULL;
 413         bool match = false;
 414
 415         val = udev_device_get_sysattr_value(dev, sysattr);
 416         if (val == NULL)
 417                 goto exit;
 418         if (match_val == NULL) {
 419                 match = true;
 420                 goto exit;
 421         }
 422         if (fnmatch(match_val, val, 0) == 0) {
 423                 match = true;
 424                 goto exit;
 425         }
 426 exit:
 427         return match;
 428 }
 429
 430 /**
 431  * udev_enumerate_add_match_property:
 432  * @udev_enumerate: context
 433  * @property: filter for a property of the device to include in the list
 434  * @value: value of the property
 435  *
 436  * Match only devices with a certain property.
 437  *
 438  * Returns: 0 on success, otherwise a negative error value.
 439  */
 440 _public_ int udev_enumerate_add_match_property(struct udev_enumerate *udev_enumerate, const char *property, const char *value)
 441 {
 442         if (udev_enumerate == NULL)
 443                 return -EINVAL;
 444         if (property == NULL)
 445                 return 0;
 446         if (udev_list_entry_add(&udev_enumerate->properties_match_list, property, value) == NULL)
 447                 return -ENOMEM;
 448         return 0;
 449 }
 450
 451 /**
 452  * udev_enumerate_add_match_tag:
 453  * @udev_enumerate: context
 454  * @tag: filter for a tag of the device to include in the list
 455  *
 456  * Match only devices with a certain tag.
 457  *
 458  * Returns: 0 on success, otherwise a negative error value.
 459  */
 460 _public_ int udev_enumerate_add_match_tag(struct udev_enumerate *udev_enumerate, const char *tag)
 461 {
 462         if (udev_enumerate == NULL)
 463                 return -EINVAL;
 464         if (tag == NULL)
 465                 return 0;
 466         if (udev_list_entry_add(&udev_enumerate->tags_match_list, tag, NULL) == NULL)
 467                 return -ENOMEM;
 468         return 0;
 469 }
 470
 471 /**
 472  * udev_enumerate_add_match_parent:
 473  * @udev_enumerate: context
 474  * @parent: parent device where to start searching
 475  *
 476  * Return the devices on the subtree of one given device. The parent
 477  * itself is included in the list.
 478  *
 479  * A reference for the device is held until the udev_enumerate context
 480  * is cleaned up.
 481  *
 482  * Returns: 0 on success, otherwise a negative error value.
 483  */
 484 _public_ int udev_enumerate_add_match_parent(struct udev_enumerate *udev_enumerate, struct udev_device *parent)
 485 {
 486         if (udev_enumerate == NULL)
 487                 return -EINVAL;
 488         if (parent == NULL)
 489                 return 0;
 490         if (udev_enumerate->parent_match != NULL)
 491                 udev_device_unref(udev_enumerate->parent_match);
 492         udev_enumerate->parent_match = udev_device_ref(parent);
 493         return 0;
 494 }
 495
 496 /**
 497  * udev_enumerate_add_match_is_initialized:
 498  * @udev_enumerate: context
 499  *
 500  * Match only devices which udev has set up already. This makes
 501  * sure, that the device node permissions and context are properly set
 502  * and that network devices are fully renamed.
 503  *
 504  * Usually, devices which are found in the kernel but not already
 505  * handled by udev, have still pending events. Services should subscribe
 506  * to monitor events and wait for these devices to become ready, instead
 507  * of using uninitialized devices.
 508  *
 509  * For now, this will not affect devices which do not have a device node
 510  * and are not network interfaces.
 511  *
 512  * Returns: 0 on success, otherwise a negative error value.
 513  */
 514 _public_ int udev_enumerate_add_match_is_initialized(struct udev_enumerate *udev_enumerate)
 515 {
 516         if (udev_enumerate == NULL)
 517                 return -EINVAL;
 518         udev_enumerate->match_is_initialized = true;
 519         return 0;
 520 }
 521
 522 /**
 523  * udev_enumerate_add_match_sysname:
 524  * @udev_enumerate: context
 525  * @sysname: filter for the name of the device to include in the list
 526  *
 527  * Match only devices with a given /sys device name.
 528  *
 529  * Returns: 0 on success, otherwise a negative error value.
 530  */
 531 _public_ int udev_enumerate_add_match_sysname(struct udev_enumerate *udev_enumerate, const char *sysname)
 532 {
 533         if (udev_enumerate == NULL)
 534                 return -EINVAL;
 535         if (sysname == NULL)
 536                 return 0;
 537         if (udev_list_entry_add(&udev_enumerate->sysname_match_list, sysname, NULL) == NULL)
 538                 return -ENOMEM;
 539         return 0;
 540 }
 541
 542 static bool match_sysattr(struct udev_enumerate *udev_enumerate, struct udev_device *dev)
 543 {
 544         struct udev_list_entry *list_entry;
 545
 546         /* skip list */
 547         udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_enumerate->sysattr_nomatch_list)) {
 548                 if (match_sysattr_value(dev, udev_list_entry_get_name(list_entry),
 549                                         udev_list_entry_get_value(list_entry)))
 550                         return false;
 551         }
 552         /* include list */
 553         if (udev_list_get_entry(&udev_enumerate->sysattr_match_list) != NULL) {
 554                 udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_enumerate->sysattr_match_list)) {
 555                         /* anything that does not match, will make it FALSE */
 556                         if (!match_sysattr_value(dev, udev_list_entry_get_name(list_entry),
 557                                                  udev_list_entry_get_value(list_entry)))
 558                                 return false;
 559                 }
 560                 return true;
 561         }
 562         return true;
 563 }
 564
 565 static bool match_property(struct udev_enumerate *udev_enumerate, struct udev_device *dev)
 566 {
 567         struct udev_list_entry *list_entry;
 568         bool match = false;
 569
 570         /* no match always matches */
 571         if (udev_list_get_entry(&udev_enumerate->properties_match_list) == NULL)
 572                 return true;
 573
 574         /* loop over matches */
 575         udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_enumerate->properties_match_list)) {
 576                 const char *match_key = udev_list_entry_get_name(list_entry);
 577                 const char *match_value = udev_list_entry_get_value(list_entry);
 578                 struct udev_list_entry *property_entry;
 579
 580                 /* loop over device properties */
 581                 udev_list_entry_foreach(property_entry, udev_device_get_properties_list_entry(dev)) {
 582                         const char *dev_key = udev_list_entry_get_name(property_entry);
 583                         const char *dev_value = udev_list_entry_get_value(property_entry);
 584
 585                         if (fnmatch(match_key, dev_key, 0) != 0)
 586                                 continue;
 587                         if (match_value == NULL && dev_value == NULL) {
 588                                 match = true;
 589                                 goto out;
 590                         }
 591                         if (match_value == NULL || dev_value == NULL)
 592                                 continue;
 593                         if (fnmatch(match_value, dev_value, 0) == 0) {
 594                                 match = true;
 595                                 goto out;
 596                         }
 597                 }
 598         }
 599 out:
 600         return match;
 601 }
 602
 603 static bool match_tag(struct udev_enumerate *udev_enumerate, struct udev_device *dev)
 604 {
 605         struct udev_list_entry *list_entry;
 606
 607         /* no match always matches */
 608         if (udev_list_get_entry(&udev_enumerate->tags_match_list) == NULL)
 609                 return true;
 610
 611         /* loop over matches */
 612         udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_enumerate->tags_match_list))
 613                 if (!udev_device_has_tag(dev, udev_list_entry_get_name(list_entry)))
 614                         return false;
 615
 616         return true;
 617 }
 618
 619 static bool match_parent(struct udev_enumerate *udev_enumerate, struct udev_device *dev)
 620 {
 621         if (udev_enumerate->parent_match == NULL)
 622                 return true;
 623
 624         return startswith(udev_device_get_devpath(dev), udev_device_get_devpath(udev_enumerate->parent_match));
 625 }
 626
 627 static bool match_sysname(struct udev_enumerate *udev_enumerate, const char *sysname)
 628 {
 629         struct udev_list_entry *list_entry;
 630
 631         if (udev_list_get_entry(&udev_enumerate->sysname_match_list) == NULL)
 632                 return true;
 633
 634         udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_enumerate->sysname_match_list)) {
 635                 if (fnmatch(udev_list_entry_get_name(list_entry), sysname, 0) != 0)
 636                         continue;
 637                 return true;
 638         }
 639         return false;
 640 }
 641
 642 static int scan_dir_and_add_devices(struct udev_enumerate *udev_enumerate,
 643                                     const char *basedir, const char *subdir1, const char *subdir2)
 644 {
 645         char path[UTIL_PATH_SIZE];
 646         size_t l;
 647         char *s;
 648         DIR *dir;
 649         struct dirent *dent;
 650
 651         s = path;
 652         l = util_strpcpyl(&s, sizeof(path), "/sys/", basedir, NULL);
 653         if (subdir1 != NULL)
 654                 l = util_strpcpyl(&s, l, "/", subdir1, NULL);
 655         if (subdir2 != NULL)
 656                 util_strpcpyl(&s, l, "/", subdir2, NULL);
 657         dir = opendir(path);
 658         if (dir == NULL)
 659                 return -ENOENT;
 660         for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
 661                 char syspath[UTIL_PATH_SIZE];
 662                 struct udev_device *dev;
 663
 664                 if (dent->d_name[0] == '.')
 665                         continue;
 666
 667                 if (!match_sysname(udev_enumerate, dent->d_name))
 668                         continue;
 669
 670                 util_strscpyl(syspath, sizeof(syspath), path, "/", dent->d_name, NULL);
 671                 dev = udev_device_new_from_syspath(udev_enumerate->udev, syspath);
 672                 if (dev == NULL)
 673                         continue;
 674
 675                 if (udev_enumerate->match_is_initialized) {
 676                         /*
 677                          * All devices with a device node or network interfaces
 678                          * possibly need udev to adjust the device node permission
 679                          * or context, or rename the interface before it can be
 680                          * reliably used from other processes.
 681                          *
 682                          * For now, we can only check these types of devices, we
 683                          * might not store a database, and have no way to find out
 684                          * for all other types of devices.
 685                          */
 686                         if (!udev_device_get_is_initialized(dev) &&
 687                             (major(udev_device_get_devnum(dev)) > 0 || udev_device_get_ifindex(dev) > 0))
 688                                 goto nomatch;
 689                 }
 690                 if (!match_parent(udev_enumerate, dev))
 691                         goto nomatch;
 692                 if (!match_tag(udev_enumerate, dev))
 693                         goto nomatch;
 694                 if (!match_property(udev_enumerate, dev))
 695                         goto nomatch;
 696                 if (!match_sysattr(udev_enumerate, dev))
 697                         goto nomatch;
 698
 699                 syspath_add(udev_enumerate, udev_device_get_syspath(dev));
 700 nomatch:
 701                 udev_device_unref(dev);
 702         }
 703         closedir(dir);
 704         return 0;
 705 }
 706
 707 static bool match_subsystem(struct udev_enumerate *udev_enumerate, const char *subsystem)
 708 {
 709         struct udev_list_entry *list_entry;
 710
 711         udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_enumerate->subsystem_nomatch_list)) {
 712                 if (fnmatch(udev_list_entry_get_name(list_entry), subsystem, 0) == 0)
 713                         return false;
 714         }
 715         if (udev_list_get_entry(&udev_enumerate->subsystem_match_list) != NULL) {
 716                 udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_enumerate->subsystem_match_list)) {
 717                         if (fnmatch(udev_list_entry_get_name(list_entry), subsystem, 0) == 0)
 718                                 return true;
 719                 }
 720                 return false;
 721         }
 722         return true;
 723 }
 724
 725 static int scan_dir(struct udev_enumerate *udev_enumerate, const char *basedir, const char *subdir, const char *subsystem)
 726 {
 727         char path[UTIL_PATH_SIZE];
 728         DIR *dir;
 729         struct dirent *dent;
 730
 731         util_strscpyl(path, sizeof(path), "/sys/", basedir, NULL);
 732         dir = opendir(path);
 733         if (dir == NULL)
 734                 return -1;
 735         for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
 736                 if (dent->d_name[0] == '.')
 737                         continue;
 738                 if (!match_subsystem(udev_enumerate, subsystem != NULL ? subsystem : dent->d_name))
 739                         continue;
 740                 scan_dir_and_add_devices(udev_enumerate, basedir, dent->d_name, subdir);
 741         }
 742         closedir(dir);
 743         return 0;
 744 }
 745
 746 /**
 747  * udev_enumerate_add_syspath:
 748  * @udev_enumerate: context
 749  * @syspath: path of a device
 750  *
 751  * Add a device to the list of devices, to retrieve it back sorted in dependency order.
 752  *
 753  * Returns: 0 on success, otherwise a negative error value.
 754  */
 755 _public_ int udev_enumerate_add_syspath(struct udev_enumerate *udev_enumerate, const char *syspath)
 756 {
 757         struct udev_device *udev_device;
 758
 759         if (udev_enumerate == NULL)
 760                 return -EINVAL;
 761         if (syspath == NULL)
 762                 return 0;
 763         /* resolve to real syspath */
 764         udev_device = udev_device_new_from_syspath(udev_enumerate->udev, syspath);
 765         if (udev_device == NULL)
 766                 return -EINVAL;
 767         syspath_add(udev_enumerate, udev_device_get_syspath(udev_device));
 768         udev_device_unref(udev_device);
 769         return 0;
 770 }
 771
 772 static int scan_devices_tags(struct udev_enumerate *udev_enumerate)
 773 {
 774         struct udev_list_entry *list_entry;
 775
 776         /* scan only tagged devices, use tags reverse-index, instead of searching all devices in /sys */
 777         udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_enumerate->tags_match_list)) {
 778                 DIR *dir;
 779                 struct dirent *dent;
 780                 char path[UTIL_PATH_SIZE];
 781
 782                 util_strscpyl(path, sizeof(path), "/run/udev/tags/", udev_list_entry_get_name(list_entry), NULL);
 783                 dir = opendir(path);
 784                 if (dir == NULL)
 785                         continue;
 786                 for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
 787                         struct udev_device *dev;
 788
 789                         if (dent->d_name[0] == '.')
 790                                 continue;
 791
 792                         dev = udev_device_new_from_id_filename(udev_enumerate->udev, dent->d_name);
 793                         if (dev == NULL)
 794                                 continue;
 795
 796                         if (!match_subsystem(udev_enumerate, udev_device_get_subsystem(dev)))
 797                                 goto nomatch;
 798                         if (!match_sysname(udev_enumerate, udev_device_get_sysname(dev)))
 799                                 goto nomatch;
 800                         if (!match_parent(udev_enumerate, dev))
 801                                 goto nomatch;
 802                         if (!match_property(udev_enumerate, dev))
 803                                 goto nomatch;
 804                         if (!match_sysattr(udev_enumerate, dev))
 805                                 goto nomatch;
 806
 807                         syspath_add(udev_enumerate, udev_device_get_syspath(dev));
 808 nomatch:
 809                         udev_device_unref(dev);
 810                 }
 811                 closedir(dir);
 812         }
 813         return 0;
 814 }
 815
 816 static int parent_add_child(struct udev_enumerate *enumerate, const char *path)
 817 {
 818         struct udev_device *dev;
 819
 820         dev = udev_device_new_from_syspath(enumerate->udev, path);
 821         if (dev == NULL)
 822                 return -ENODEV;
 823
 824         if (!match_subsystem(enumerate, udev_device_get_subsystem(dev)))
 825                 return 0;
 826         if (!match_sysname(enumerate, udev_device_get_sysname(dev)))
 827                 return 0;
 828         if (!match_property(enumerate, dev))
 829                 return 0;
 830         if (!match_sysattr(enumerate, dev))
 831                 return 0;
 832
 833         syspath_add(enumerate, udev_device_get_syspath(dev));
 834         udev_device_unref(dev);
 835         return 1;
 836 }
 837
 838 static int parent_crawl_children(struct udev_enumerate *enumerate, const char *path, int maxdepth)
 839 {
 840         DIR *d;
 841         struct dirent *dent;
 842
 843         d = opendir(path);
 844         if (d == NULL)
 845                 return -errno;
 846
 847         for (dent = readdir(d); dent != NULL; dent = readdir(d)) {
 848                 char *child;
 849
 850                 if (dent->d_name[0] == '.')
 851                         continue;
 852                 if (dent->d_type != DT_DIR)
 853                         continue;
 854                 if (asprintf(&child, "%s/%s", path, dent->d_name) < 0)
 855                         continue;
 856                 parent_add_child(enumerate, child);
 857                 if (maxdepth > 0)
 858                         parent_crawl_children(enumerate, child, maxdepth-1);
 859                 free(child);
 860         }
 861
 862         closedir(d);
 863         return 0;
 864 }
 865
 866 static int scan_devices_children(struct udev_enumerate *enumerate)
 867 {
 868         const char *path;
 869
 870         path = udev_device_get_syspath(enumerate->parent_match);
 871         parent_add_child(enumerate, path);
 872         return parent_crawl_children(enumerate, path, 256);
 873 }
 874
 875 static int scan_devices_all(struct udev_enumerate *udev_enumerate)
 876 {
 877         struct stat statbuf;
 878
 879         if (stat("/sys/subsystem", &statbuf) == 0) {
 880                 /* we have /subsystem/, forget all the old stuff */
 881                 scan_dir(udev_enumerate, "subsystem", "devices", NULL);
 882         } else {
 883                 scan_dir(udev_enumerate, "bus", "devices", NULL);
 884                 scan_dir(udev_enumerate, "class", NULL, NULL);
 885         }
 886         return 0;
 887 }
 888
 889 /**
 890  * udev_enumerate_scan_devices:
 891  * @udev_enumerate: udev enumeration context
 892  *
 893  * Scan /sys for all devices which match the given filters. No matches
 894  * will return all currently available devices.
 895  *
 896  * Returns: 0 on success, otherwise a negative error value.
 897  **/
 898 _public_ int udev_enumerate_scan_devices(struct udev_enumerate *udev_enumerate)
 899 {
 900         if (udev_enumerate == NULL)
 901                 return -EINVAL;
 902
 903         /* efficiently lookup tags only, we maintain a reverse-index */
 904         if (udev_list_get_entry(&udev_enumerate->tags_match_list) != NULL)
 905                 return scan_devices_tags(udev_enumerate);
 906
 907         /* walk the subtree of one parent device only */
 908         if (udev_enumerate->parent_match != NULL)
 909                 return scan_devices_children(udev_enumerate);
 910
 911         /* scan devices of all subsystems */
 912         return scan_devices_all(udev_enumerate);
 913 }
 914
 915 /**
 916  * udev_enumerate_scan_subsystems:
 917  * @udev_enumerate: udev enumeration context
 918  *
 919  * Scan /sys for all kernel subsystems, including buses, classes, drivers.
 920  *
 921  * Returns: 0 on success, otherwise a negative error value.
 922  **/
 923 _public_ int udev_enumerate_scan_subsystems(struct udev_enumerate *udev_enumerate)
 924 {
 925         struct stat statbuf;
 926         const char *subsysdir;
 927
 928         if (udev_enumerate == NULL)
 929                 return -EINVAL;
 930
 931         /* all kernel modules */
 932         if (match_subsystem(udev_enumerate, "module"))
 933                 scan_dir_and_add_devices(udev_enumerate, "module", NULL, NULL);
 934
 935         if (stat("/sys/subsystem", &statbuf) == 0)
 936                 subsysdir = "subsystem";
 937         else
 938                 subsysdir = "bus";
 939
 940         /* all subsystems (only buses support coldplug) */
 941         if (match_subsystem(udev_enumerate, "subsystem"))
 942                 scan_dir_and_add_devices(udev_enumerate, subsysdir, NULL, NULL);
 943
 944         /* all subsystem drivers */
 945         if (match_subsystem(udev_enumerate, "drivers"))
 946                 scan_dir(udev_enumerate, subsysdir, "drivers", "drivers");
 947         return 0;
 948 }