src/libudev/libudev-enumerate.c

   1 /***
   2   This file is part of systemd.
   3
   4   Copyright 2008-2012 Kay Sievers <kay@vrfy.org>
   5
   6   systemd is free software; you can redistribute it and/or modify it
   7   under the terms of the GNU Lesser General Public License as published by
   8   the Free Software Foundation; either version 2.1 of the License, or
   9   (at your option) any later version.
  10
  11   systemd is distributed in the hope that it will be useful, but
  12   WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  14   Lesser General Public License for more details.
  15
  16   You should have received a copy of the GNU Lesser General Public License
  17   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  18 ***/
  19
  20 #include <stdio.h>
  21 #include <stdlib.h>
  22 #include <stddef.h>
  23 #include <unistd.h>
  24 #include <errno.h>
  25 #include <string.h>
  26 #include <dirent.h>
  27 #include <fnmatch.h>
  28 #include <stdbool.h>
  29 #include <sys/stat.h>
  30 #include <sys/param.h>
  31
  32 #include "libudev.h"
  33 #include "libudev-private.h"
  34
  35 /**
  36  * SECTION:libudev-enumerate
  37  * @short_description: lookup and sort sys devices
  38  *
  39  * Lookup devices in the sys filesystem, filter devices by properties,
  40  * and return a sorted list of devices.
  41  */
  42
  43 struct syspath {
  44         char *syspath;
  45         size_t len;
  46 };
  47
  48 /**
  49  * udev_enumerate:
  50  *
  51  * Opaque object representing one device lookup/sort context.
  52  */
  53 struct udev_enumerate {
  54         struct udev *udev;
  55         int refcount;
  56         struct udev_list sysattr_match_list;
  57         struct udev_list sysattr_nomatch_list;
  58         struct udev_list subsystem_match_list;
  59         struct udev_list subsystem_nomatch_list;
  60         struct udev_list sysname_match_list;
  61         struct udev_list properties_match_list;
  62         struct udev_list tags_match_list;
  63         struct udev_device *parent_match;
  64         struct udev_list devices_list;
  65         struct syspath *devices;
  66         unsigned int devices_cur;
  67         unsigned int devices_max;
  68         bool devices_uptodate:1;
  69         bool match_is_initialized;
  70 };
  71
  72 /**
  73  * udev_enumerate_new:
  74  * @udev: udev library context
  75  *
  76  * Create an enumeration context to scan /sys.
  77  *
  78  * Returns: an enumeration context.
  79  **/
  80 _public_ struct udev_enumerate *udev_enumerate_new(struct udev *udev)
  81 {
  82         struct udev_enumerate *udev_enumerate;
  83
  84         if (udev == NULL)
  85                 return NULL;
  86         udev_enumerate = new0(struct udev_enumerate, 1);
  87         if (udev_enumerate == NULL)
  88                 return NULL;
  89         udev_enumerate->refcount = 1;
  90         udev_enumerate->udev = udev;
  91         udev_list_init(udev, &udev_enumerate->sysattr_match_list, false);
  92         udev_list_init(udev, &udev_enumerate->sysattr_nomatch_list, false);
  93         udev_list_init(udev, &udev_enumerate->subsystem_match_list, true);
  94         udev_list_init(udev, &udev_enumerate->subsystem_nomatch_list, true);
  95         udev_list_init(udev, &udev_enumerate->sysname_match_list, true);
  96         udev_list_init(udev, &udev_enumerate->properties_match_list, false);
  97         udev_list_init(udev, &udev_enumerate->tags_match_list, true);
  98         udev_list_init(udev, &udev_enumerate->devices_list, false);
  99         return udev_enumerate;
 100 }
 101
 102 /**
 103  * udev_enumerate_ref:
 104  * @udev_enumerate: context
 105  *
 106  * Take a reference of a enumeration context.
 107  *
 108  * Returns: the passed enumeration context
 109  **/
 110 _public_ struct udev_enumerate *udev_enumerate_ref(struct udev_enumerate *udev_enumerate)
 111 {
 112         if (udev_enumerate == NULL)
 113                 return NULL;
 114         udev_enumerate->refcount++;
 115         return udev_enumerate;
 116 }
 117
 118 /**
 119  * udev_enumerate_unref:
 120  * @udev_enumerate: context
 121  *
 122  * Drop a reference of an enumeration context. If the refcount reaches zero,
 123  * all resources of the enumeration context will be released.
 124  *
 125  * Returns: #NULL
 126  **/
 127 _public_ struct udev_enumerate *udev_enumerate_unref(struct udev_enumerate *udev_enumerate)
 128 {
 129         unsigned int i;
 130
 131         if (udev_enumerate == NULL)
 132                 return NULL;
 133         udev_enumerate->refcount--;
 134         if (udev_enumerate->refcount > 0)
 135                 return NULL;
 136         udev_list_cleanup(&udev_enumerate->sysattr_match_list);
 137         udev_list_cleanup(&udev_enumerate->sysattr_nomatch_list);
 138         udev_list_cleanup(&udev_enumerate->subsystem_match_list);
 139         udev_list_cleanup(&udev_enumerate->subsystem_nomatch_list);
 140         udev_list_cleanup(&udev_enumerate->sysname_match_list);
 141         udev_list_cleanup(&udev_enumerate->properties_match_list);
 142         udev_list_cleanup(&udev_enumerate->tags_match_list);
 143         udev_device_unref(udev_enumerate->parent_match);
 144         udev_list_cleanup(&udev_enumerate->devices_list);
 145         for (i = 0; i < udev_enumerate->devices_cur; i++)
 146                 free(udev_enumerate->devices[i].syspath);
 147         free(udev_enumerate->devices);
 148         free(udev_enumerate);
 149         return NULL;
 150 }
 151
 152 /**
 153  * udev_enumerate_get_udev:
 154  * @udev_enumerate: context
 155  *
 156  * Get the udev library context.
 157  *
 158  * Returns: a pointer to the context.
 159  */
 160 _public_ struct udev *udev_enumerate_get_udev(struct udev_enumerate *udev_enumerate)
 161 {
 162         if (udev_enumerate == NULL)
 163                 return NULL;
 164         return udev_enumerate->udev;
 165 }
 166
 167 static int syspath_add(struct udev_enumerate *udev_enumerate, const char *syspath)
 168 {
 169         char *path;
 170         struct syspath *entry;
 171
 172         /* double array size if needed */
 173         if (udev_enumerate->devices_cur >= udev_enumerate->devices_max) {
 174                 struct syspath *buf;
 175                 unsigned int add;
 176
 177                 add = udev_enumerate->devices_max;
 178                 if (add < 1024)
 179                         add = 1024;
 180                 buf = realloc(udev_enumerate->devices, (udev_enumerate->devices_max + add) * sizeof(struct syspath));
 181                 if (buf == NULL)
 182                         return -ENOMEM;
 183                 udev_enumerate->devices = buf;
 184                 udev_enumerate->devices_max += add;
 185         }
 186
 187         path = strdup(syspath);
 188         if (path == NULL)
 189                 return -ENOMEM;
 190         entry = &udev_enumerate->devices[udev_enumerate->devices_cur];
 191         entry->syspath = path;
 192         entry->len = strlen(path);
 193         udev_enumerate->devices_cur++;
 194         udev_enumerate->devices_uptodate = false;
 195         return 0;
 196 }
 197
 198 static int syspath_cmp(const void *p1, const void *p2)
 199 {
 200         const struct syspath *path1 = p1;
 201         const struct syspath *path2 = p2;
 202         size_t len;
 203         int ret;
 204
 205         len = MIN(path1->len, path2->len);
 206         ret = memcmp(path1->syspath, path2->syspath, len);
 207         if (ret == 0) {
 208                 if (path1->len < path2->len)
 209                         ret = -1;
 210                 else if (path1->len > path2->len)
 211                         ret = 1;
 212         }
 213         return ret;
 214 }
 215
 216 /* For devices that should be moved to the absolute end of the list */
 217 static bool devices_delay_end(struct udev *udev, const char *syspath)
 218 {
 219         static const char *delay_device_list[] = {
 220                 "/block/md",
 221                 "/block/dm-",
 222                 NULL
 223         };
 224         int i;
 225
 226         for (i = 0; delay_device_list[i] != NULL; i++) {
 227                 if (strstr(syspath + strlen("/sys"), delay_device_list[i]) != NULL)
 228                         return true;
 229         }
 230         return false;
 231 }
 232
 233 /* For devices that should just be moved a little bit later, just
 234  * before the point where some common path prefix changes. Returns the
 235  * number of characters that make up that common prefix */
 236 static size_t devices_delay_later(struct udev *udev, const char *syspath)
 237 {
 238         const char *c;
 239
 240         /* For sound cards the control device must be enumerated last
 241          * to make sure it's the final device node that gets ACLs
 242          * applied. Applications rely on this fact and use ACL changes
 243          * on the control node as an indicator that the ACL change of
 244          * the entire sound card completed. The kernel makes this
 245          * guarantee when creating those devices, and hence we should
 246          * too when enumerating them. */
 247
 248         if ((c = strstr(syspath, "/sound/card"))) {
 249                 c += 11;
 250                 c += strcspn(c, "/");
 251
 252                 if (startswith(c, "/controlC"))
 253                         return c - syspath + 1;
 254         }
 255
 256         return 0;
 257 }
 258
 259 /**
 260  * udev_enumerate_get_list_entry:
 261  * @udev_enumerate: context
 262  *
 263  * Get the first entry of the sorted list of device paths.
 264  *
 265  * Returns: a udev_list_entry.
 266  */
 267 _public_ struct udev_list_entry *udev_enumerate_get_list_entry(struct udev_enumerate *udev_enumerate)
 268 {
 269         if (udev_enumerate == NULL)
 270                 return NULL;
 271         if (!udev_enumerate->devices_uptodate) {
 272                 unsigned int i;
 273                 int move_later = -1;
 274                 unsigned int max;
 275                 struct syspath *prev = NULL;
 276                 size_t move_later_prefix = 0;
 277
 278                 udev_list_cleanup(&udev_enumerate->devices_list);
 279                 qsort_safe(udev_enumerate->devices, udev_enumerate->devices_cur, sizeof(struct syspath), syspath_cmp);
 280
 281                 max = udev_enumerate->devices_cur;
 282                 for (i = 0; i < max; i++) {
 283                         struct syspath *entry = &udev_enumerate->devices[i];
 284
 285                         /* skip duplicated entries */
 286                         if (prev != NULL &&
 287                             entry->len == prev->len &&
 288                             memcmp(entry->syspath, prev->syspath, entry->len) == 0)
 289                                 continue;
 290                         prev = entry;
 291
 292                         /* skip to be delayed devices, and add them to the end of the list */
 293                         if (devices_delay_end(udev_enumerate->udev, entry->syspath)) {
 294                                 syspath_add(udev_enumerate, entry->syspath);
 295                                 /* need to update prev here for the case realloc() gives a different address */
 296                                 prev = &udev_enumerate->devices[i];
 297                                 continue;
 298                         }
 299
 300                         /* skip to be delayed devices, and move the to
 301                          * the point where the prefix changes. We can
 302                          * only move one item at a time. */
 303                         if (move_later == -1) {
 304                                 move_later_prefix = devices_delay_later(udev_enumerate->udev, entry->syspath);
 305
 306                                 if (move_later_prefix > 0) {
 307                                         move_later = i;
 308                                         continue;
 309                                 }
 310                         }
 311
 312                         if ((move_later >= 0) &&
 313                              !strneq(entry->syspath, udev_enumerate->devices[move_later].syspath, move_later_prefix)) {
 314
 315                                 udev_list_entry_add(&udev_enumerate->devices_list,
 316                                                     udev_enumerate->devices[move_later].syspath, NULL);
 317                                 move_later = -1;
 318                         }
 319
 320                         udev_list_entry_add(&udev_enumerate->devices_list, entry->syspath, NULL);
 321                 }
 322
 323                 if (move_later >= 0)
 324                         udev_list_entry_add(&udev_enumerate->devices_list,
 325                                             udev_enumerate->devices[move_later].syspath, NULL);
 326
 327                 /* add and cleanup delayed devices from end of list */
 328                 for (i = max; i < udev_enumerate->devices_cur; i++) {
 329                         struct syspath *entry = &udev_enumerate->devices[i];
 330
 331                         udev_list_entry_add(&udev_enumerate->devices_list, entry->syspath, NULL);
 332                         free(entry->syspath);
 333                 }
 334                 udev_enumerate->devices_cur = max;
 335
 336                 udev_enumerate->devices_uptodate = true;
 337         }
 338         return udev_list_get_entry(&udev_enumerate->devices_list);
 339 }
 340
 341 /**
 342  * udev_enumerate_add_match_subsystem:
 343  * @udev_enumerate: context
 344  * @subsystem: filter for a subsystem of the device to include in the list
 345  *
 346  * Match only devices belonging to a certain kernel subsystem.
 347  *
 348  * Returns: 0 on success, otherwise a negative error value.
 349  */
 350 _public_ int udev_enumerate_add_match_subsystem(struct udev_enumerate *udev_enumerate, const char *subsystem)
 351 {
 352         if (udev_enumerate == NULL)
 353                 return -EINVAL;
 354         if (subsystem == NULL)
 355                 return 0;
 356         if (udev_list_entry_add(&udev_enumerate->subsystem_match_list, subsystem, NULL) == NULL)
 357                 return -ENOMEM;
 358         return 0;
 359 }
 360
 361 /**
 362  * udev_enumerate_add_nomatch_subsystem:
 363  * @udev_enumerate: context
 364  * @subsystem: filter for a subsystem of the device to exclude from the list
 365  *
 366  * Match only devices not belonging to a certain kernel subsystem.
 367  *
 368  * Returns: 0 on success, otherwise a negative error value.
 369  */
 370 _public_ int udev_enumerate_add_nomatch_subsystem(struct udev_enumerate *udev_enumerate, const char *subsystem)
 371 {
 372         if (udev_enumerate == NULL)
 373                 return -EINVAL;
 374         if (subsystem == NULL)
 375                 return 0;
 376         if (udev_list_entry_add(&udev_enumerate->subsystem_nomatch_list, subsystem, NULL) == NULL)
 377                 return -ENOMEM;
 378         return 0;
 379 }
 380
 381 /**
 382  * udev_enumerate_add_match_sysattr:
 383  * @udev_enumerate: context
 384  * @sysattr: filter for a sys attribute at the device to include in the list
 385  * @value: optional value of the sys attribute
 386  *
 387  * Match only devices with a certain /sys device attribute.
 388  *
 389  * Returns: 0 on success, otherwise a negative error value.
 390  */
 391 _public_ int udev_enumerate_add_match_sysattr(struct udev_enumerate *udev_enumerate, const char *sysattr, const char *value)
 392 {
 393         if (udev_enumerate == NULL)
 394                 return -EINVAL;
 395         if (sysattr == NULL)
 396                 return 0;
 397         if (udev_list_entry_add(&udev_enumerate->sysattr_match_list, sysattr, value) == NULL)
 398                 return -ENOMEM;
 399         return 0;
 400 }
 401
 402 /**
 403  * udev_enumerate_add_nomatch_sysattr:
 404  * @udev_enumerate: context
 405  * @sysattr: filter for a sys attribute at the device to exclude from the list
 406  * @value: optional value of the sys attribute
 407  *
 408  * Match only devices not having a certain /sys device attribute.
 409  *
 410  * Returns: 0 on success, otherwise a negative error value.
 411  */
 412 _public_ int udev_enumerate_add_nomatch_sysattr(struct udev_enumerate *udev_enumerate, const char *sysattr, const char *value)
 413 {
 414         if (udev_enumerate == NULL)
 415                 return -EINVAL;
 416         if (sysattr == NULL)
 417                 return 0;
 418         if (udev_list_entry_add(&udev_enumerate->sysattr_nomatch_list, sysattr, value) == NULL)
 419                 return -ENOMEM;
 420         return 0;
 421 }
 422
 423 static int match_sysattr_value(struct udev_device *dev, const char *sysattr, const char *match_val)
 424 {
 425         const char *val = NULL;
 426         bool match = false;
 427
 428         val = udev_device_get_sysattr_value(dev, sysattr);
 429         if (val == NULL)
 430                 goto exit;
 431         if (match_val == NULL) {
 432                 match = true;
 433                 goto exit;
 434         }
 435         if (fnmatch(match_val, val, 0) == 0) {
 436                 match = true;
 437                 goto exit;
 438         }
 439 exit:
 440         return match;
 441 }
 442
 443 /**
 444  * udev_enumerate_add_match_property:
 445  * @udev_enumerate: context
 446  * @property: filter for a property of the device to include in the list
 447  * @value: value of the property
 448  *
 449  * Match only devices with a certain property.
 450  *
 451  * Returns: 0 on success, otherwise a negative error value.
 452  */
 453 _public_ int udev_enumerate_add_match_property(struct udev_enumerate *udev_enumerate, const char *property, const char *value)
 454 {
 455         if (udev_enumerate == NULL)
 456                 return -EINVAL;
 457         if (property == NULL)
 458                 return 0;
 459         if (udev_list_entry_add(&udev_enumerate->properties_match_list, property, value) == NULL)
 460                 return -ENOMEM;
 461         return 0;
 462 }
 463
 464 /**
 465  * udev_enumerate_add_match_tag:
 466  * @udev_enumerate: context
 467  * @tag: filter for a tag of the device to include in the list
 468  *
 469  * Match only devices with a certain tag.
 470  *
 471  * Returns: 0 on success, otherwise a negative error value.
 472  */
 473 _public_ int udev_enumerate_add_match_tag(struct udev_enumerate *udev_enumerate, const char *tag)
 474 {
 475         if (udev_enumerate == NULL)
 476                 return -EINVAL;
 477         if (tag == NULL)
 478                 return 0;
 479         if (udev_list_entry_add(&udev_enumerate->tags_match_list, tag, NULL) == NULL)
 480                 return -ENOMEM;
 481         return 0;
 482 }
 483
 484 /**
 485  * udev_enumerate_add_match_parent:
 486  * @udev_enumerate: context
 487  * @parent: parent device where to start searching
 488  *
 489  * Return the devices on the subtree of one given device. The parent
 490  * itself is included in the list.
 491  *
 492  * A reference for the device is held until the udev_enumerate context
 493  * is cleaned up.
 494  *
 495  * Returns: 0 on success, otherwise a negative error value.
 496  */
 497 _public_ int udev_enumerate_add_match_parent(struct udev_enumerate *udev_enumerate, struct udev_device *parent)
 498 {
 499         if (udev_enumerate == NULL)
 500                 return -EINVAL;
 501         if (parent == NULL)
 502                 return 0;
 503         if (udev_enumerate->parent_match != NULL)
 504                 udev_device_unref(udev_enumerate->parent_match);
 505         udev_enumerate->parent_match = udev_device_ref(parent);
 506         return 0;
 507 }
 508
 509 /**
 510  * udev_enumerate_add_match_is_initialized:
 511  * @udev_enumerate: context
 512  *
 513  * Match only devices which udev has set up already. This makes
 514  * sure, that the device node permissions and context are properly set
 515  * and that network devices are fully renamed.
 516  *
 517  * Usually, devices which are found in the kernel but not already
 518  * handled by udev, have still pending events. Services should subscribe
 519  * to monitor events and wait for these devices to become ready, instead
 520  * of using uninitialized devices.
 521  *
 522  * For now, this will not affect devices which do not have a device node
 523  * and are not network interfaces.
 524  *
 525  * Returns: 0 on success, otherwise a negative error value.
 526  */
 527 _public_ int udev_enumerate_add_match_is_initialized(struct udev_enumerate *udev_enumerate)
 528 {
 529         if (udev_enumerate == NULL)
 530                 return -EINVAL;
 531         udev_enumerate->match_is_initialized = true;
 532         return 0;
 533 }
 534
 535 /**
 536  * udev_enumerate_add_match_sysname:
 537  * @udev_enumerate: context
 538  * @sysname: filter for the name of the device to include in the list
 539  *
 540  * Match only devices with a given /sys device name.
 541  *
 542  * Returns: 0 on success, otherwise a negative error value.
 543  */
 544 _public_ int udev_enumerate_add_match_sysname(struct udev_enumerate *udev_enumerate, const char *sysname)
 545 {
 546         if (udev_enumerate == NULL)
 547                 return -EINVAL;
 548         if (sysname == NULL)
 549                 return 0;
 550         if (udev_list_entry_add(&udev_enumerate->sysname_match_list, sysname, NULL) == NULL)
 551                 return -ENOMEM;
 552         return 0;
 553 }
 554
 555 static bool match_sysattr(struct udev_enumerate *udev_enumerate, struct udev_device *dev)
 556 {
 557         struct udev_list_entry *list_entry;
 558
 559         /* skip list */
 560         udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_enumerate->sysattr_nomatch_list)) {
 561                 if (match_sysattr_value(dev, udev_list_entry_get_name(list_entry),
 562                                         udev_list_entry_get_value(list_entry)))
 563                         return false;
 564         }
 565         /* include list */
 566         if (udev_list_get_entry(&udev_enumerate->sysattr_match_list) != NULL) {
 567                 udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_enumerate->sysattr_match_list)) {
 568                         /* anything that does not match, will make it FALSE */
 569                         if (!match_sysattr_value(dev, udev_list_entry_get_name(list_entry),
 570                                                  udev_list_entry_get_value(list_entry)))
 571                                 return false;
 572                 }
 573                 return true;
 574         }
 575         return true;
 576 }
 577
 578 static bool match_property(struct udev_enumerate *udev_enumerate, struct udev_device *dev)
 579 {
 580         struct udev_list_entry *list_entry;
 581         bool match = false;
 582
 583         /* no match always matches */
 584         if (udev_list_get_entry(&udev_enumerate->properties_match_list) == NULL)
 585                 return true;
 586
 587         /* loop over matches */
 588         udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_enumerate->properties_match_list)) {
 589                 const char *match_key = udev_list_entry_get_name(list_entry);
 590                 const char *match_value = udev_list_entry_get_value(list_entry);
 591                 struct udev_list_entry *property_entry;
 592
 593                 /* loop over device properties */
 594                 udev_list_entry_foreach(property_entry, udev_device_get_properties_list_entry(dev)) {
 595                         const char *dev_key = udev_list_entry_get_name(property_entry);
 596                         const char *dev_value = udev_list_entry_get_value(property_entry);
 597
 598                         if (fnmatch(match_key, dev_key, 0) != 0)
 599                                 continue;
 600                         if (match_value == NULL && dev_value == NULL) {
 601                                 match = true;
 602                                 goto out;
 603                         }
 604                         if (match_value == NULL || dev_value == NULL)
 605                                 continue;
 606                         if (fnmatch(match_value, dev_value, 0) == 0) {
 607                                 match = true;
 608                                 goto out;
 609                         }
 610                 }
 611         }
 612 out:
 613         return match;
 614 }
 615
 616 static bool match_tag(struct udev_enumerate *udev_enumerate, struct udev_device *dev)
 617 {
 618         struct udev_list_entry *list_entry;
 619
 620         /* no match always matches */
 621         if (udev_list_get_entry(&udev_enumerate->tags_match_list) == NULL)
 622                 return true;
 623
 624         /* loop over matches */
 625         udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_enumerate->tags_match_list))
 626                 if (!udev_device_has_tag(dev, udev_list_entry_get_name(list_entry)))
 627                         return false;
 628
 629         return true;
 630 }
 631
 632 static bool match_parent(struct udev_enumerate *udev_enumerate, struct udev_device *dev)
 633 {
 634         if (udev_enumerate->parent_match == NULL)
 635                 return true;
 636
 637         return startswith(udev_device_get_devpath(dev), udev_device_get_devpath(udev_enumerate->parent_match));
 638 }
 639
 640 static bool match_sysname(struct udev_enumerate *udev_enumerate, const char *sysname)
 641 {
 642         struct udev_list_entry *list_entry;
 643
 644         if (udev_list_get_entry(&udev_enumerate->sysname_match_list) == NULL)
 645                 return true;
 646
 647         udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_enumerate->sysname_match_list)) {
 648                 if (fnmatch(udev_list_entry_get_name(list_entry), sysname, 0) != 0)
 649                         continue;
 650                 return true;
 651         }
 652         return false;
 653 }
 654
 655 static int scan_dir_and_add_devices(struct udev_enumerate *udev_enumerate,
 656                                     const char *basedir, const char *subdir1, const char *subdir2)
 657 {
 658         char path[UTIL_PATH_SIZE];
 659         size_t l;
 660         char *s;
 661         DIR *dir;
 662         struct dirent *dent;
 663
 664         s = path;
 665         l = strpcpyl(&s, sizeof(path), "/sys/", basedir, NULL);
 666         if (subdir1 != NULL)
 667                 l = strpcpyl(&s, l, "/", subdir1, NULL);
 668         if (subdir2 != NULL)
 669                 strpcpyl(&s, l, "/", subdir2, NULL);
 670         dir = opendir(path);
 671         if (dir == NULL)
 672                 return -ENOENT;
 673         for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
 674                 char syspath[UTIL_PATH_SIZE];
 675                 struct udev_device *dev;
 676
 677                 if (dent->d_name[0] == '.')
 678                         continue;
 679
 680                 if (!match_sysname(udev_enumerate, dent->d_name))
 681                         continue;
 682
 683                 strscpyl(syspath, sizeof(syspath), path, "/", dent->d_name, NULL);
 684                 dev = udev_device_new_from_syspath(udev_enumerate->udev, syspath);
 685                 if (dev == NULL)
 686                         continue;
 687
 688                 if (udev_enumerate->match_is_initialized) {
 689                         /*
 690                          * All devices with a device node or network interfaces
 691                          * possibly need udev to adjust the device node permission
 692                          * or context, or rename the interface before it can be
 693                          * reliably used from other processes.
 694                          *
 695                          * For now, we can only check these types of devices, we
 696                          * might not store a database, and have no way to find out
 697                          * for all other types of devices.
 698                          */
 699                         if (!udev_device_get_is_initialized(dev) &&
 700                             (major(udev_device_get_devnum(dev)) > 0 || udev_device_get_ifindex(dev) > 0))
 701                                 goto nomatch;
 702                 }
 703                 if (!match_parent(udev_enumerate, dev))
 704                         goto nomatch;
 705                 if (!match_tag(udev_enumerate, dev))
 706                         goto nomatch;
 707                 if (!match_property(udev_enumerate, dev))
 708                         goto nomatch;
 709                 if (!match_sysattr(udev_enumerate, dev))
 710                         goto nomatch;
 711
 712                 syspath_add(udev_enumerate, udev_device_get_syspath(dev));
 713 nomatch:
 714                 udev_device_unref(dev);
 715         }
 716         closedir(dir);
 717         return 0;
 718 }
 719
 720 static bool match_subsystem(struct udev_enumerate *udev_enumerate, const char *subsystem)
 721 {
 722         struct udev_list_entry *list_entry;
 723
 724         if (!subsystem)
 725                 return false;
 726
 727         udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_enumerate->subsystem_nomatch_list)) {
 728                 if (fnmatch(udev_list_entry_get_name(list_entry), subsystem, 0) == 0)
 729                         return false;
 730         }
 731
 732         if (udev_list_get_entry(&udev_enumerate->subsystem_match_list) != NULL) {
 733                 udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_enumerate->subsystem_match_list)) {
 734                         if (fnmatch(udev_list_entry_get_name(list_entry), subsystem, 0) == 0)
 735                                 return true;
 736                 }
 737                 return false;
 738         }
 739
 740         return true;
 741 }
 742
 743 static int scan_dir(struct udev_enumerate *udev_enumerate, const char *basedir, const char *subdir, const char *subsystem)
 744 {
 745         char path[UTIL_PATH_SIZE];
 746         DIR *dir;
 747         struct dirent *dent;
 748
 749         strscpyl(path, sizeof(path), "/sys/", basedir, NULL);
 750         dir = opendir(path);
 751         if (dir == NULL)
 752                 return -1;
 753         for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
 754                 if (dent->d_name[0] == '.')
 755                         continue;
 756                 if (!match_subsystem(udev_enumerate, subsystem != NULL ? subsystem : dent->d_name))
 757                         continue;
 758                 scan_dir_and_add_devices(udev_enumerate, basedir, dent->d_name, subdir);
 759         }
 760         closedir(dir);
 761         return 0;
 762 }
 763
 764 /**
 765  * udev_enumerate_add_syspath:
 766  * @udev_enumerate: context
 767  * @syspath: path of a device
 768  *
 769  * Add a device to the list of devices, to retrieve it back sorted in dependency order.
 770  *
 771  * Returns: 0 on success, otherwise a negative error value.
 772  */
 773 _public_ int udev_enumerate_add_syspath(struct udev_enumerate *udev_enumerate, const char *syspath)
 774 {
 775         struct udev_device *udev_device;
 776
 777         if (udev_enumerate == NULL)
 778                 return -EINVAL;
 779         if (syspath == NULL)
 780                 return 0;
 781         /* resolve to real syspath */
 782         udev_device = udev_device_new_from_syspath(udev_enumerate->udev, syspath);
 783         if (udev_device == NULL)
 784                 return -EINVAL;
 785         syspath_add(udev_enumerate, udev_device_get_syspath(udev_device));
 786         udev_device_unref(udev_device);
 787         return 0;
 788 }
 789
 790 static int scan_devices_tags(struct udev_enumerate *udev_enumerate)
 791 {
 792         struct udev_list_entry *list_entry;
 793
 794         /* scan only tagged devices, use tags reverse-index, instead of searching all devices in /sys */
 795         udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_enumerate->tags_match_list)) {
 796                 DIR *dir;
 797                 struct dirent *dent;
 798                 char path[UTIL_PATH_SIZE];
 799
 800                 strscpyl(path, sizeof(path), "/run/udev/tags/", udev_list_entry_get_name(list_entry), NULL);
 801                 dir = opendir(path);
 802                 if (dir == NULL)
 803                         continue;
 804                 for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
 805                         struct udev_device *dev;
 806
 807                         if (dent->d_name[0] == '.')
 808                                 continue;
 809
 810                         dev = udev_device_new_from_device_id(udev_enumerate->udev, dent->d_name);
 811                         if (dev == NULL)
 812                                 continue;
 813
 814                         if (!match_subsystem(udev_enumerate, udev_device_get_subsystem(dev)))
 815                                 goto nomatch;
 816                         if (!match_sysname(udev_enumerate, udev_device_get_sysname(dev)))
 817                                 goto nomatch;
 818                         if (!match_parent(udev_enumerate, dev))
 819                                 goto nomatch;
 820                         if (!match_property(udev_enumerate, dev))
 821                                 goto nomatch;
 822                         if (!match_sysattr(udev_enumerate, dev))
 823                                 goto nomatch;
 824
 825                         syspath_add(udev_enumerate, udev_device_get_syspath(dev));
 826 nomatch:
 827                         udev_device_unref(dev);
 828                 }
 829                 closedir(dir);
 830         }
 831         return 0;
 832 }
 833
 834 static int parent_add_child(struct udev_enumerate *enumerate, const char *path)
 835 {
 836         struct udev_device *dev;
 837         int r = 0;
 838
 839         dev = udev_device_new_from_syspath(enumerate->udev, path);
 840         if (dev == NULL)
 841                 return -ENODEV;
 842
 843         if (!match_subsystem(enumerate, udev_device_get_subsystem(dev)))
 844                 goto nomatch;
 845         if (!match_sysname(enumerate, udev_device_get_sysname(dev)))
 846                 goto nomatch;
 847         if (!match_property(enumerate, dev))
 848                 goto nomatch;
 849         if (!match_sysattr(enumerate, dev))
 850                 goto nomatch;
 851
 852         syspath_add(enumerate, udev_device_get_syspath(dev));
 853         r = 1;
 854
 855 nomatch:
 856         udev_device_unref(dev);
 857         return r;
 858 }
 859
 860 static int parent_crawl_children(struct udev_enumerate *enumerate, const char *path, int maxdepth)
 861 {
 862         DIR *d;
 863         struct dirent *dent;
 864
 865         d = opendir(path);
 866         if (d == NULL)
 867                 return -errno;
 868
 869         for (dent = readdir(d); dent != NULL; dent = readdir(d)) {
 870                 char *child;
 871
 872                 if (dent->d_name[0] == '.')
 873                         continue;
 874                 if (dent->d_type != DT_DIR)
 875                         continue;
 876                 if (asprintf(&child, "%s/%s", path, dent->d_name) < 0)
 877                         continue;
 878                 parent_add_child(enumerate, child);
 879                 if (maxdepth > 0)
 880                         parent_crawl_children(enumerate, child, maxdepth-1);
 881                 free(child);
 882         }
 883
 884         closedir(d);
 885         return 0;
 886 }
 887
 888 static int scan_devices_children(struct udev_enumerate *enumerate)
 889 {
 890         const char *path;
 891
 892         path = udev_device_get_syspath(enumerate->parent_match);
 893         parent_add_child(enumerate, path);
 894         return parent_crawl_children(enumerate, path, 256);
 895 }
 896
 897 static int scan_devices_all(struct udev_enumerate *udev_enumerate)
 898 {
 899         struct stat statbuf;
 900
 901         if (stat("/sys/subsystem", &statbuf) == 0) {
 902                 /* we have /subsystem/, forget all the old stuff */
 903                 scan_dir(udev_enumerate, "subsystem", "devices", NULL);
 904         } else {
 905                 scan_dir(udev_enumerate, "bus", "devices", NULL);
 906                 scan_dir(udev_enumerate, "class", NULL, NULL);
 907         }
 908         return 0;
 909 }
 910
 911 /**
 912  * udev_enumerate_scan_devices:
 913  * @udev_enumerate: udev enumeration context
 914  *
 915  * Scan /sys for all devices which match the given filters. No matches
 916  * will return all currently available devices.
 917  *
 918  * Returns: 0 on success, otherwise a negative error value.
 919  **/
 920 _public_ int udev_enumerate_scan_devices(struct udev_enumerate *udev_enumerate)
 921 {
 922         if (udev_enumerate == NULL)
 923                 return -EINVAL;
 924
 925         /* efficiently lookup tags only, we maintain a reverse-index */
 926         if (udev_list_get_entry(&udev_enumerate->tags_match_list) != NULL)
 927                 return scan_devices_tags(udev_enumerate);
 928
 929         /* walk the subtree of one parent device only */
 930         if (udev_enumerate->parent_match != NULL)
 931                 return scan_devices_children(udev_enumerate);
 932
 933         /* scan devices of all subsystems */
 934         return scan_devices_all(udev_enumerate);
 935 }
 936
 937 /**
 938  * udev_enumerate_scan_subsystems:
 939  * @udev_enumerate: udev enumeration context
 940  *
 941  * Scan /sys for all kernel subsystems, including buses, classes, drivers.
 942  *
 943  * Returns: 0 on success, otherwise a negative error value.
 944  **/
 945 _public_ int udev_enumerate_scan_subsystems(struct udev_enumerate *udev_enumerate)
 946 {
 947         struct stat statbuf;
 948         const char *subsysdir;
 949
 950         if (udev_enumerate == NULL)
 951                 return -EINVAL;
 952
 953         /* all kernel modules */
 954         if (match_subsystem(udev_enumerate, "module"))
 955                 scan_dir_and_add_devices(udev_enumerate, "module", NULL, NULL);
 956
 957         if (stat("/sys/subsystem", &statbuf) == 0)
 958                 subsysdir = "subsystem";
 959         else
 960                 subsysdir = "bus";
 961
 962         /* all subsystems (only buses support coldplug) */
 963         if (match_subsystem(udev_enumerate, "subsystem"))
 964                 scan_dir_and_add_devices(udev_enumerate, subsysdir, NULL, NULL);
 965
 966         /* all subsystem drivers */
 967         if (match_subsystem(udev_enumerate, "drivers"))
 968                 scan_dir(udev_enumerate, subsysdir, "drivers", "drivers");
 969         return 0;
 970 }